Update 4.8.1 to 4.8.3.

My previous drop was the wrong version. The platform mingw is
currently using 4.8.3, not 4.8.1 (not sure how I got that wrong).

From ftp://ftp.gnu.org/gnu/gcc/gcc-4.8.3/gcc-4.8.3.tar.bz2.

Bug: http://b/26523949
Change-Id: Id85f1bdcbbaf78c7d0b5a69e74c798a08f341c35

1 files changed, 21164 insertions, 0 deletions

diff --git a/gcc-4.8.3/gcc/doc/invoke.texi b/gcc-4.8.3/gcc/doc/invoke.texi
new file mode 100644
index 000000000..c39192b7f
--- /dev/null
+++ b/gcc-4.8.3/gcc/doc/invoke.texi
@@ -0,0 +1,21164 @@
+@c Copyright (C) 1988-2013 Free Software Foundation, Inc.
+@c This is part of the GCC manual.
+@c For copying conditions, see the file gcc.texi.
+
+@ignore
+@c man begin INCLUDE
+@include gcc-vers.texi
+@c man end
+
+@c man begin COPYRIGHT
+Copyright @copyright{} 1988-2013 Free Software Foundation, Inc.
+
+Permission is granted to copy, distribute and/or modify this document
+under the terms of the GNU Free Documentation License, Version 1.3 or
+any later version published by the Free Software Foundation; with the
+Invariant Sections being ``GNU General Public License'' and ``Funding
+Free Software'', the Front-Cover texts being (a) (see below), and with
+the Back-Cover Texts being (b) (see below).  A copy of the license is
+included in the gfdl(7) man page.
+
+(a) The FSF's Front-Cover Text is:
+
+     A GNU Manual
+
+(b) The FSF's Back-Cover Text is:
+
+     You have freedom to copy and modify this GNU Manual, like GNU
+     software.  Copies published by the Free Software Foundation raise
+     funds for GNU development.
+@c man end
+@c Set file name and title for the man page.
+@setfilename gcc
+@settitle GNU project C and C++ compiler
+@c man begin SYNOPSIS
+gcc [@option{-c}|@option{-S}|@option{-E}] [@option{-std=}@var{standard}]
+    [@option{-g}] [@option{-pg}] [@option{-O}@var{level}]
+    [@option{-W}@var{warn}@dots{}] [@option{-Wpedantic}]
+    [@option{-I}@var{dir}@dots{}] [@option{-L}@var{dir}@dots{}]
+    [@option{-D}@var{macro}[=@var{defn}]@dots{}] [@option{-U}@var{macro}]
+    [@option{-f}@var{option}@dots{}] [@option{-m}@var{machine-option}@dots{}]
+    [@option{-o} @var{outfile}] [@@@var{file}] @var{infile}@dots{}
+
+Only the most useful options are listed here; see below for the
+remainder.  @samp{g++} accepts mostly the same options as @samp{gcc}.
+@c man end
+@c man begin SEEALSO
+gpl(7), gfdl(7), fsf-funding(7),
+cpp(1), gcov(1), as(1), ld(1), gdb(1), adb(1), dbx(1), sdb(1)
+and the Info entries for @file{gcc}, @file{cpp}, @file{as},
+@file{ld}, @file{binutils} and @file{gdb}.
+@c man end
+@c man begin BUGS
+For instructions on reporting bugs, see
+@w{@value{BUGURL}}.
+@c man end
+@c man begin AUTHOR
+See the Info entry for @command{gcc}, or
+@w{@uref{http://gcc.gnu.org/onlinedocs/gcc/Contributors.html}},
+for contributors to GCC@.
+@c man end
+@end ignore
+
+@node Invoking GCC
+@chapter GCC Command Options
+@cindex GCC command options
+@cindex command options
+@cindex options, GCC command
+
+@c man begin DESCRIPTION
+When you invoke GCC, it normally does preprocessing, compilation,
+assembly and linking.  The ``overall options'' allow you to stop this
+process at an intermediate stage.  For example, the @option{-c} option
+says not to run the linker.  Then the output consists of object files
+output by the assembler.
+
+Other options are passed on to one stage of processing.  Some options
+control the preprocessor and others the compiler itself.  Yet other
+options control the assembler and linker; most of these are not
+documented here, since you rarely need to use any of them.
+
+@cindex C compilation options
+Most of the command-line options that you can use with GCC are useful
+for C programs; when an option is only useful with another language
+(usually C++), the explanation says so explicitly.  If the description
+for a particular option does not mention a source language, you can use
+that option with all supported languages.
+
+@cindex C++ compilation options
+@xref{Invoking G++,,Compiling C++ Programs}, for a summary of special
+options for compiling C++ programs.
+
+@cindex grouping options
+@cindex options, grouping
+The @command{gcc} program accepts options and file names as operands.  Many
+options have multi-letter names; therefore multiple single-letter options
+may @emph{not} be grouped: @option{-dv} is very different from @w{@samp{-d
+-v}}.
+
+@cindex order of options
+@cindex options, order
+You can mix options and other arguments.  For the most part, the order
+you use doesn't matter.  Order does matter when you use several
+options of the same kind; for example, if you specify @option{-L} more
+than once, the directories are searched in the order specified.  Also,
+the placement of the @option{-l} option is significant.
+
+Many options have long names starting with @samp{-f} or with
+@samp{-W}---for example,
+@option{-fmove-loop-invariants}, @option{-Wformat} and so on.  Most of
+these have both positive and negative forms; the negative form of
+@option{-ffoo} is @option{-fno-foo}.  This manual documents
+only one of these two forms, whichever one is not the default.
+
+@c man end
+
+@xref{Option Index}, for an index to GCC's options.
+
+@menu
+* Option Summary::      Brief list of all options, without explanations.
+* Overall Options::     Controlling the kind of output:
+                        an executable, object files, assembler files,
+                        or preprocessed source.
+* Invoking G++::        Compiling C++ programs.
+* C Dialect Options::   Controlling the variant of C language compiled.
+* C++ Dialect Options:: Variations on C++.
+* Objective-C and Objective-C++ Dialect Options:: Variations on Objective-C
+                        and Objective-C++.
+* Language Independent Options:: Controlling how diagnostics should be
+                        formatted.
+* Warning Options::     How picky should the compiler be?
+* Debugging Options::   Symbol tables, measurements, and debugging dumps.
+* Optimize Options::    How much optimization?
+* Preprocessor Options:: Controlling header files and macro definitions.
+                         Also, getting dependency information for Make.
+* Assembler Options::   Passing options to the assembler.
+* Link Options::        Specifying libraries and so on.
+* Directory Options::   Where to find header files and libraries.
+                        Where to find the compiler executable files.
+* Spec Files::          How to pass switches to sub-processes.
+* Target Options::      Running a cross-compiler, or an old version of GCC.
+* Submodel Options::    Specifying minor hardware or convention variations,
+                        such as 68010 vs 68020.
+* Code Gen Options::    Specifying conventions for function calls, data layout
+                        and register usage.
+* Environment Variables:: Env vars that affect GCC.
+* Precompiled Headers:: Compiling a header once, and using it many times.
+@end menu
+
+@c man begin OPTIONS
+
+@node Option Summary
+@section Option Summary
+
+Here is a summary of all the options, grouped by type.  Explanations are
+in the following sections.
+
+@table @emph
+@item Overall Options
+@xref{Overall Options,,Options Controlling the Kind of Output}.
+@gccoptlist{-c  -S  -E  -o @var{file}  -no-canonical-prefixes  @gol
+-pipe  -pass-exit-codes  @gol
+-x @var{language}  -v  -###  --help@r{[}=@var{class}@r{[},@dots{}@r{]]}  --target-help  @gol
+--version -wrapper @@@var{file} -fplugin=@var{file} -fplugin-arg-@var{name}=@var{arg}  @gol
+-fdump-ada-spec@r{[}-slim@r{]} -fada-spec-parent=@var{unit} -fdump-go-spec=@var{file}}
+
+@item C Language Options
+@xref{C Dialect Options,,Options Controlling C Dialect}.
+@gccoptlist{-ansi  -std=@var{standard}  -fgnu89-inline @gol
+-aux-info @var{filename} -fallow-parameterless-variadic-functions @gol
+-fno-asm  -fno-builtin  -fno-builtin-@var{function} @gol
+-fhosted  -ffreestanding -fopenmp -fms-extensions -fplan9-extensions @gol
+-trigraphs  -traditional  -traditional-cpp @gol
+-fallow-single-precision  -fcond-mismatch -flax-vector-conversions @gol
+-fsigned-bitfields  -fsigned-char @gol
+-funsigned-bitfields  -funsigned-char}
+
+@item C++ Language Options
+@xref{C++ Dialect Options,,Options Controlling C++ Dialect}.
+@gccoptlist{-fabi-version=@var{n}  -fno-access-control  -fcheck-new @gol
+-fconstexpr-depth=@var{n}  -ffriend-injection @gol
+-fno-elide-constructors @gol
+-fno-enforce-eh-specs @gol
+-ffor-scope  -fno-for-scope  -fno-gnu-keywords @gol
+-fno-implicit-templates @gol
+-fno-implicit-inline-templates @gol
+-fno-implement-inlines  -fms-extensions @gol
+-fno-nonansi-builtins  -fnothrow-opt  -fno-operator-names @gol
+-fno-optional-diags  -fpermissive @gol
+-fno-pretty-templates @gol
+-frepo  -fno-rtti  -fstats  -ftemplate-backtrace-limit=@var{n} @gol
+-ftemplate-depth=@var{n} @gol
+-fno-threadsafe-statics -fuse-cxa-atexit  -fno-weak  -nostdinc++ @gol
+-fno-default-inline  -fvisibility-inlines-hidden @gol
+-fvisibility-ms-compat @gol
+-fext-numeric-literals @gol
+-Wabi  -Wconversion-null  -Wctor-dtor-privacy @gol
+-Wdelete-non-virtual-dtor -Wliteral-suffix -Wnarrowing @gol
+-Wnoexcept -Wnon-virtual-dtor  -Wreorder @gol
+-Weffc++  -Wstrict-null-sentinel @gol
+-Wno-non-template-friend  -Wold-style-cast @gol
+-Woverloaded-virtual  -Wno-pmf-conversions @gol
+-Wsign-promo}
+
+@item Objective-C and Objective-C++ Language Options
+@xref{Objective-C and Objective-C++ Dialect Options,,Options Controlling
+Objective-C and Objective-C++ Dialects}.
+@gccoptlist{-fconstant-string-class=@var{class-name} @gol
+-fgnu-runtime  -fnext-runtime @gol
+-fno-nil-receivers @gol
+-fobjc-abi-version=@var{n} @gol
+-fobjc-call-cxx-cdtors @gol
+-fobjc-direct-dispatch @gol
+-fobjc-exceptions @gol
+-fobjc-gc @gol
+-fobjc-nilcheck @gol
+-fobjc-std=objc1 @gol
+-freplace-objc-classes @gol
+-fzero-link @gol
+-gen-decls @gol
+-Wassign-intercept @gol
+-Wno-protocol  -Wselector @gol
+-Wstrict-selector-match @gol
+-Wundeclared-selector}
+
+@item Language Independent Options
+@xref{Language Independent Options,,Options to Control Diagnostic Messages Formatting}.
+@gccoptlist{-fmessage-length=@var{n}  @gol
+-fdiagnostics-show-location=@r{[}once@r{|}every-line@r{]}  @gol
+-fno-diagnostics-show-option -fno-diagnostics-show-caret}
+
+@item Warning Options
+@xref{Warning Options,,Options to Request or Suppress Warnings}.
+@gccoptlist{-fsyntax-only  -fmax-errors=@var{n}  -Wpedantic @gol
+-pedantic-errors @gol
+-w  -Wextra  -Wall  -Waddress  -Waggregate-return  @gol
+-Waggressive-loop-optimizations -Warray-bounds @gol
+-Wno-attributes -Wno-builtin-macro-redefined @gol
+-Wc++-compat -Wc++11-compat -Wcast-align  -Wcast-qual  @gol
+-Wchar-subscripts -Wclobbered  -Wcomment @gol
+-Wconversion  -Wcoverage-mismatch  -Wno-cpp  -Wno-deprecated  @gol
+-Wno-deprecated-declarations -Wdisabled-optimization  @gol
+-Wno-div-by-zero -Wdouble-promotion -Wempty-body  -Wenum-compare @gol
+-Wno-endif-labels -Werror  -Werror=* @gol
+-Wfatal-errors  -Wfloat-equal  -Wformat  -Wformat=2 @gol
+-Wno-format-contains-nul -Wno-format-extra-args -Wformat-nonliteral @gol
+-Wformat-security  -Wformat-y2k @gol
+-Wframe-larger-than=@var{len} -Wno-free-nonheap-object -Wjump-misses-init @gol
+-Wignored-qualifiers @gol
+-Wimplicit  -Wimplicit-function-declaration  -Wimplicit-int @gol
+-Winit-self  -Winline -Wmaybe-uninitialized @gol
+-Wno-int-to-pointer-cast -Wno-invalid-offsetof @gol
+-Winvalid-pch -Wlarger-than=@var{len}  -Wunsafe-loop-optimizations @gol
+-Wlogical-op -Wlong-long @gol
+-Wmain -Wmaybe-uninitialized -Wmissing-braces  -Wmissing-field-initializers @gol
+-Wmissing-include-dirs @gol
+-Wno-mudflap @gol
+-Wno-multichar  -Wnonnull  -Wno-overflow @gol
+-Woverlength-strings  -Wpacked  -Wpacked-bitfield-compat  -Wpadded @gol
+-Wparentheses  -Wpedantic-ms-format -Wno-pedantic-ms-format @gol
+-Wpointer-arith  -Wno-pointer-to-int-cast @gol
+-Wredundant-decls  -Wno-return-local-addr @gol
+-Wreturn-type  -Wsequence-point  -Wshadow @gol
+-Wsign-compare  -Wsign-conversion  -Wsizeof-pointer-memaccess @gol
+-Wstack-protector -Wstack-usage=@var{len} -Wstrict-aliasing @gol
+-Wstrict-aliasing=n @gol -Wstrict-overflow -Wstrict-overflow=@var{n} @gol
+-Wsuggest-attribute=@r{[}pure@r{|}const@r{|}noreturn@r{|}format@r{]} @gol
+-Wmissing-format-attribute @gol
+-Wswitch  -Wswitch-default  -Wswitch-enum -Wsync-nand @gol
+-Wsystem-headers  -Wtrampolines  -Wtrigraphs  -Wtype-limits  -Wundef @gol
+-Wuninitialized  -Wunknown-pragmas  -Wno-pragmas @gol
+-Wunsuffixed-float-constants  -Wunused  -Wunused-function @gol
+-Wunused-label  -Wunused-local-typedefs -Wunused-parameter @gol
+-Wno-unused-result -Wunused-value @gol -Wunused-variable @gol
+-Wunused-but-set-parameter -Wunused-but-set-variable @gol
+-Wuseless-cast -Wvariadic-macros -Wvector-operation-performance @gol
+-Wvla -Wvolatile-register-var  -Wwrite-strings -Wzero-as-null-pointer-constant}
+
+@item C and Objective-C-only Warning Options
+@gccoptlist{-Wbad-function-cast  -Wmissing-declarations @gol
+-Wmissing-parameter-type  -Wmissing-prototypes  -Wnested-externs @gol
+-Wold-style-declaration  -Wold-style-definition @gol
+-Wstrict-prototypes  -Wtraditional  -Wtraditional-conversion @gol
+-Wdeclaration-after-statement -Wpointer-sign}
+
+@item Debugging Options
+@xref{Debugging Options,,Options for Debugging Your Program or GCC}.
+@gccoptlist{-d@var{letters}  -dumpspecs  -dumpmachine  -dumpversion @gol
+-fsanitize=@var{style} @gol
+-fdbg-cnt-list -fdbg-cnt=@var{counter-value-list} @gol
+-fdisable-ipa-@var{pass_name} @gol
+-fdisable-rtl-@var{pass_name} @gol
+-fdisable-rtl-@var{pass-name}=@var{range-list} @gol
+-fdisable-tree-@var{pass_name} @gol
+-fdisable-tree-@var{pass-name}=@var{range-list} @gol
+-fdump-noaddr -fdump-unnumbered -fdump-unnumbered-links @gol
+-fdump-translation-unit@r{[}-@var{n}@r{]} @gol
+-fdump-class-hierarchy@r{[}-@var{n}@r{]} @gol
+-fdump-ipa-all -fdump-ipa-cgraph -fdump-ipa-inline @gol
+-fdump-passes @gol
+-fdump-statistics @gol
+-fdump-tree-all @gol
+-fdump-tree-original@r{[}-@var{n}@r{]}  @gol
+-fdump-tree-optimized@r{[}-@var{n}@r{]} @gol
+-fdump-tree-cfg -fdump-tree-alias @gol
+-fdump-tree-ch @gol
+-fdump-tree-ssa@r{[}-@var{n}@r{]} -fdump-tree-pre@r{[}-@var{n}@r{]} @gol
+-fdump-tree-ccp@r{[}-@var{n}@r{]} -fdump-tree-dce@r{[}-@var{n}@r{]} @gol
+-fdump-tree-gimple@r{[}-raw@r{]} -fdump-tree-mudflap@r{[}-@var{n}@r{]} @gol
+-fdump-tree-dom@r{[}-@var{n}@r{]} @gol
+-fdump-tree-dse@r{[}-@var{n}@r{]} @gol
+-fdump-tree-phiprop@r{[}-@var{n}@r{]} @gol
+-fdump-tree-phiopt@r{[}-@var{n}@r{]} @gol
+-fdump-tree-forwprop@r{[}-@var{n}@r{]} @gol
+-fdump-tree-copyrename@r{[}-@var{n}@r{]} @gol
+-fdump-tree-nrv -fdump-tree-vect @gol
+-fdump-tree-sink @gol
+-fdump-tree-sra@r{[}-@var{n}@r{]} @gol
+-fdump-tree-forwprop@r{[}-@var{n}@r{]} @gol
+-fdump-tree-fre@r{[}-@var{n}@r{]} @gol
+-fdump-tree-vrp@r{[}-@var{n}@r{]} @gol
+-ftree-vectorizer-verbose=@var{n} @gol
+-fdump-tree-storeccp@r{[}-@var{n}@r{]} @gol
+-fdump-final-insns=@var{file} @gol
+-fcompare-debug@r{[}=@var{opts}@r{]}  -fcompare-debug-second @gol
+-feliminate-dwarf2-dups -fno-eliminate-unused-debug-types @gol
+-feliminate-unused-debug-symbols -femit-class-debug-always @gol
+-fenable-@var{kind}-@var{pass} @gol
+-fenable-@var{kind}-@var{pass}=@var{range-list} @gol
+-fdebug-types-section -fmem-report-wpa @gol
+-fmem-report -fpre-ipa-mem-report -fpost-ipa-mem-report -fprofile-arcs @gol
+-fopt-info @gol
+-fopt-info-@var{options}@r{[}=@var{file}@r{]} @gol
+-frandom-seed=@var{string} -fsched-verbose=@var{n} @gol
+-fsel-sched-verbose -fsel-sched-dump-cfg -fsel-sched-pipelining-verbose @gol
+-fstack-usage  -ftest-coverage  -ftime-report -fvar-tracking @gol
+-fvar-tracking-assignments  -fvar-tracking-assignments-toggle @gol
+-g  -g@var{level}  -gtoggle  -gcoff  -gdwarf-@var{version} @gol
+-ggdb  -grecord-gcc-switches  -gno-record-gcc-switches @gol
+-gstabs  -gstabs+  -gstrict-dwarf  -gno-strict-dwarf @gol
+-gvms  -gxcoff  -gxcoff+ @gol
+-fno-merge-debug-strings -fno-dwarf2-cfi-asm @gol
+-fdebug-prefix-map=@var{old}=@var{new} @gol
+-femit-struct-debug-baseonly -femit-struct-debug-reduced @gol
+-femit-struct-debug-detailed@r{[}=@var{spec-list}@r{]} @gol
+-p  -pg  -print-file-name=@var{library}  -print-libgcc-file-name @gol
+-print-multi-directory  -print-multi-lib  -print-multi-os-directory @gol
+-print-prog-name=@var{program}  -print-search-dirs  -Q @gol
+-print-sysroot -print-sysroot-headers-suffix @gol
+-save-temps -save-temps=cwd -save-temps=obj -time@r{[}=@var{file}@r{]}}
+
+@item Optimization Options
+@xref{Optimize Options,,Options that Control Optimization}.
+@gccoptlist{-faggressive-loop-optimizations -falign-functions[=@var{n}] @gol
+-falign-jumps[=@var{n}] @gol
+-falign-labels[=@var{n}] -falign-loops[=@var{n}] @gol
+-fassociative-math -fauto-inc-dec -fbranch-probabilities @gol
+-fbranch-target-load-optimize -fbranch-target-load-optimize2 @gol
+-fbtr-bb-exclusive -fcaller-saves @gol
+-fcheck-data-deps -fcombine-stack-adjustments -fconserve-stack @gol
+-fcompare-elim -fcprop-registers -fcrossjumping @gol
+-fcse-follow-jumps -fcse-skip-blocks -fcx-fortran-rules @gol
+-fcx-limited-range @gol
+-fdata-sections -fdce -fdelayed-branch @gol
+-fdelete-null-pointer-checks -fdevirtualize -fdse @gol
+-fearly-inlining -fipa-sra -fexpensive-optimizations -ffat-lto-objects @gol
+-ffast-math -ffinite-math-only -ffloat-store -fexcess-precision=@var{style} @gol
+-fforward-propagate -ffp-contract=@var{style} -ffunction-sections @gol
+-fgcse -fgcse-after-reload -fgcse-las -fgcse-lm -fgraphite-identity @gol
+-fgcse-sm -fhoist-adjacent-loads -fif-conversion @gol
+-fif-conversion2 -findirect-inlining @gol
+-finline-functions -finline-functions-called-once -finline-limit=@var{n} @gol
+-finline-small-functions -fipa-cp -fipa-cp-clone @gol
+-fipa-pta -fipa-profile -fipa-pure-const -fipa-reference @gol
+-fira-algorithm=@var{algorithm} @gol
+-fira-region=@var{region} -fira-hoist-pressure @gol
+-fira-loop-pressure -fno-ira-share-save-slots @gol
+-fno-ira-share-spill-slots -fira-verbose=@var{n} @gol
+-fivopts -fkeep-inline-functions -fkeep-static-consts @gol
+-floop-block -floop-interchange -floop-strip-mine -floop-nest-optimize @gol
+-floop-parallelize-all -flto -flto-compression-level @gol
+-flto-partition=@var{alg} -flto-report -fmerge-all-constants @gol
+-fmerge-constants -fmodulo-sched -fmodulo-sched-allow-regmoves @gol
+-fmove-loop-invariants fmudflap -fmudflapir -fmudflapth -fno-branch-count-reg @gol
+-fno-default-inline @gol
+-fno-defer-pop -fno-function-cse -fno-guess-branch-probability @gol
+-fno-inline -fno-math-errno -fno-peephole -fno-peephole2 @gol
+-fno-sched-interblock -fno-sched-spec -fno-signed-zeros @gol
+-fno-toplevel-reorder -fno-trapping-math -fno-zero-initialized-in-bss @gol
+-fomit-frame-pointer -foptimize-register-move -foptimize-sibling-calls @gol
+-fpartial-inlining -fpeel-loops -fpredictive-commoning @gol
+-fprefetch-loop-arrays -fprofile-report @gol
+-fprofile-correction -fprofile-dir=@var{path} -fprofile-generate @gol
+-fprofile-generate=@var{path} @gol
+-fprofile-use -fprofile-use=@var{path} -fprofile-values @gol
+-freciprocal-math -free -fregmove -frename-registers -freorder-blocks @gol
+-freorder-blocks-and-partition -freorder-functions @gol
+-frerun-cse-after-loop -freschedule-modulo-scheduled-loops @gol
+-frounding-math -fsched2-use-superblocks -fsched-pressure @gol
+-fsched-spec-load -fsched-spec-load-dangerous @gol
+-fsched-stalled-insns-dep[=@var{n}] -fsched-stalled-insns[=@var{n}] @gol
+-fsched-group-heuristic -fsched-critical-path-heuristic @gol
+-fsched-spec-insn-heuristic -fsched-rank-heuristic @gol
+-fsched-last-insn-heuristic -fsched-dep-count-heuristic @gol
+-fschedule-insns -fschedule-insns2 -fsection-anchors @gol
+-fselective-scheduling -fselective-scheduling2 @gol
+-fsel-sched-pipelining -fsel-sched-pipelining-outer-loops @gol
+-fshrink-wrap -fsignaling-nans -fsingle-precision-constant @gol
+-fsplit-ivs-in-unroller -fsplit-wide-types -fstack-protector @gol
+-fstack-protector-all -fstrict-aliasing -fstrict-overflow @gol
+-fthread-jumps -ftracer -ftree-bit-ccp @gol
+-ftree-builtin-call-dce -ftree-ccp -ftree-ch @gol
+-ftree-coalesce-inline-vars -ftree-coalesce-vars -ftree-copy-prop @gol
+-ftree-copyrename -ftree-dce -ftree-dominator-opts -ftree-dse @gol
+-ftree-forwprop -ftree-fre -ftree-loop-if-convert @gol
+-ftree-loop-if-convert-stores -ftree-loop-im @gol
+-ftree-phiprop -ftree-loop-distribution -ftree-loop-distribute-patterns @gol
+-ftree-loop-ivcanon -ftree-loop-linear -ftree-loop-optimize @gol
+-ftree-parallelize-loops=@var{n} -ftree-pre -ftree-partial-pre -ftree-pta @gol
+-ftree-reassoc -ftree-sink -ftree-slsr -ftree-sra @gol
+-ftree-switch-conversion -ftree-tail-merge @gol
+-ftree-ter -ftree-vect-loop-version -ftree-vectorize -ftree-vrp @gol
+-funit-at-a-time -funroll-all-loops -funroll-loops @gol
+-funsafe-loop-optimizations -funsafe-math-optimizations -funswitch-loops @gol
+-fvariable-expansion-in-unroller -fvect-cost-model -fvpt -fweb @gol
+-fwhole-program -fwpa -fuse-ld=@var{linker} -fuse-linker-plugin @gol
+--param @var{name}=@var{value}
+-O  -O0  -O1  -O2  -O3  -Os -Ofast -Og}
+
+@item Preprocessor Options
+@xref{Preprocessor Options,,Options Controlling the Preprocessor}.
+@gccoptlist{-A@var{question}=@var{answer} @gol
+-A-@var{question}@r{[}=@var{answer}@r{]} @gol
+-C  -dD  -dI  -dM  -dN @gol
+-D@var{macro}@r{[}=@var{defn}@r{]}  -E  -H @gol
+-idirafter @var{dir} @gol
+-include @var{file}  -imacros @var{file} @gol
+-iprefix @var{file}  -iwithprefix @var{dir} @gol
+-iwithprefixbefore @var{dir}  -isystem @var{dir} @gol
+-imultilib @var{dir} -isysroot @var{dir} @gol
+-M  -MM  -MF  -MG  -MP  -MQ  -MT  -nostdinc  @gol
+-P  -fdebug-cpp -ftrack-macro-expansion -fworking-directory @gol
+-remap -trigraphs  -undef  -U@var{macro}  @gol
+-Wp,@var{option} -Xpreprocessor @var{option} -no-integrated-cpp}
+
+@item Assembler Option
+@xref{Assembler Options,,Passing Options to the Assembler}.
+@gccoptlist{-Wa,@var{option}  -Xassembler @var{option}}
+
+@item Linker Options
+@xref{Link Options,,Options for Linking}.
+@gccoptlist{@var{object-file-name}  -l@var{library} @gol
+-nostartfiles  -nodefaultlibs  -nostdlib -pie -rdynamic @gol
+-s  -static -static-libgcc -static-libstdc++ @gol
+-static-libasan -static-libtsan @gol
+-shared -shared-libgcc  -symbolic @gol
+-T @var{script}  -Wl,@var{option}  -Xlinker @var{option} @gol
+-u @var{symbol}}
+
+@item Directory Options
+@xref{Directory Options,,Options for Directory Search}.
+@gccoptlist{-B@var{prefix} -I@var{dir} -iplugindir=@var{dir} @gol
+-iquote@var{dir} -L@var{dir} -specs=@var{file} -I- @gol
+--sysroot=@var{dir} --no-sysroot-suffix}
+
+@item Machine Dependent Options
+@xref{Submodel Options,,Hardware Models and Configurations}.
+@c This list is ordered alphanumerically by subsection name.
+@c Try and put the significant identifier (CPU or system) first,
+@c so users have a clue at guessing where the ones they want will be.
+
+@emph{AArch64 Options}
+@gccoptlist{-mbig-endian  -mlittle-endian @gol
+-mgeneral-regs-only @gol
+-mcmodel=tiny  -mcmodel=small  -mcmodel=large @gol
+-mstrict-align @gol
+-momit-leaf-frame-pointer  -mno-omit-leaf-frame-pointer @gol
+-mtls-dialect=desc  -mtls-dialect=traditional @gol
+-march=@var{name}  -mcpu=@var{name}  -mtune=@var{name}}
+
+@emph{Adapteva Epiphany Options}
+@gccoptlist{-mhalf-reg-file -mprefer-short-insn-regs @gol
+-mbranch-cost=@var{num} -mcmove -mnops=@var{num} -msoft-cmpsf @gol
+-msplit-lohi -mpost-inc -mpost-modify -mstack-offset=@var{num} @gol
+-mround-nearest -mlong-calls -mshort-calls -msmall16 @gol
+-mfp-mode=@var{mode} -mvect-double -max-vect-align=@var{num} @gol
+-msplit-vecmove-early -m1reg-@var{reg}}
+
+@emph{ARM Options}
+@gccoptlist{-mapcs-frame  -mno-apcs-frame @gol
+-mabi=@var{name} @gol
+-mapcs-stack-check  -mno-apcs-stack-check @gol
+-mapcs-float  -mno-apcs-float @gol
+-mapcs-reentrant  -mno-apcs-reentrant @gol
+-msched-prolog  -mno-sched-prolog @gol
+-mlittle-endian  -mbig-endian  -mwords-little-endian @gol
+-mfloat-abi=@var{name} @gol
+-mfp16-format=@var{name}
+-mthumb-interwork  -mno-thumb-interwork @gol
+-mcpu=@var{name}  -march=@var{name}  -mfpu=@var{name}  @gol
+-mstructure-size-boundary=@var{n} @gol
+-mabort-on-noreturn @gol
+-mlong-calls  -mno-long-calls @gol
+-msingle-pic-base  -mno-single-pic-base @gol
+-mpic-register=@var{reg} @gol
+-mnop-fun-dllimport @gol
+-mpoke-function-name @gol
+-mthumb  -marm @gol
+-mtpcs-frame  -mtpcs-leaf-frame @gol
+-mcaller-super-interworking  -mcallee-super-interworking @gol
+-mtp=@var{name} -mtls-dialect=@var{dialect} @gol
+-mword-relocations @gol
+-mfix-cortex-m3-ldrd @gol
+-munaligned-access}
+
+@emph{AVR Options}
+@gccoptlist{-mmcu=@var{mcu} -maccumulate-args -mbranch-cost=@var{cost} @gol
+-mcall-prologues -mint8 -mno-interrupts -mrelax @gol
+-mstrict-X -mtiny-stack -Waddr-space-convert}
+
+@emph{Blackfin Options}
+@gccoptlist{-mcpu=@var{cpu}@r{[}-@var{sirevision}@r{]} @gol
+-msim -momit-leaf-frame-pointer  -mno-omit-leaf-frame-pointer @gol
+-mspecld-anomaly  -mno-specld-anomaly  -mcsync-anomaly  -mno-csync-anomaly @gol
+-mlow-64k -mno-low64k  -mstack-check-l1  -mid-shared-library @gol
+-mno-id-shared-library  -mshared-library-id=@var{n} @gol
+-mleaf-id-shared-library  -mno-leaf-id-shared-library @gol
+-msep-data  -mno-sep-data  -mlong-calls  -mno-long-calls @gol
+-mfast-fp -minline-plt -mmulticore  -mcorea  -mcoreb  -msdram @gol
+-micplb}
+
+@emph{C6X Options}
+@gccoptlist{-mbig-endian  -mlittle-endian -march=@var{cpu} @gol
+-msim -msdata=@var{sdata-type}}
+
+@emph{CRIS Options}
+@gccoptlist{-mcpu=@var{cpu}  -march=@var{cpu}  -mtune=@var{cpu} @gol
+-mmax-stack-frame=@var{n}  -melinux-stacksize=@var{n} @gol
+-metrax4  -metrax100  -mpdebug  -mcc-init  -mno-side-effects @gol
+-mstack-align  -mdata-align  -mconst-align @gol
+-m32-bit  -m16-bit  -m8-bit  -mno-prologue-epilogue  -mno-gotplt @gol
+-melf  -maout  -melinux  -mlinux  -sim  -sim2 @gol
+-mmul-bug-workaround  -mno-mul-bug-workaround}
+
+@emph{CR16 Options}
+@gccoptlist{-mmac @gol
+-mcr16cplus -mcr16c @gol
+-msim -mint32 -mbit-ops
+-mdata-model=@var{model}}
+
+@emph{Darwin Options}
+@gccoptlist{-all_load  -allowable_client  -arch  -arch_errors_fatal @gol
+-arch_only  -bind_at_load  -bundle  -bundle_loader @gol
+-client_name  -compatibility_version  -current_version @gol
+-dead_strip @gol
+-dependency-file  -dylib_file  -dylinker_install_name @gol
+-dynamic  -dynamiclib  -exported_symbols_list @gol
+-filelist  -flat_namespace  -force_cpusubtype_ALL @gol
+-force_flat_namespace  -headerpad_max_install_names @gol
+-iframework @gol
+-image_base  -init  -install_name  -keep_private_externs @gol
+-multi_module  -multiply_defined  -multiply_defined_unused @gol
+-noall_load   -no_dead_strip_inits_and_terms @gol
+-nofixprebinding -nomultidefs  -noprebind  -noseglinkedit @gol
+-pagezero_size  -prebind  -prebind_all_twolevel_modules @gol
+-private_bundle  -read_only_relocs  -sectalign @gol
+-sectobjectsymbols  -whyload  -seg1addr @gol
+-sectcreate  -sectobjectsymbols  -sectorder @gol
+-segaddr -segs_read_only_addr -segs_read_write_addr @gol
+-seg_addr_table  -seg_addr_table_filename  -seglinkedit @gol
+-segprot  -segs_read_only_addr  -segs_read_write_addr @gol
+-single_module  -static  -sub_library  -sub_umbrella @gol
+-twolevel_namespace  -umbrella  -undefined @gol
+-unexported_symbols_list  -weak_reference_mismatches @gol
+-whatsloaded -F -gused -gfull -mmacosx-version-min=@var{version} @gol
+-mkernel -mone-byte-bool}
+
+@emph{DEC Alpha Options}
+@gccoptlist{-mno-fp-regs  -msoft-float @gol
+-mieee  -mieee-with-inexact  -mieee-conformant @gol
+-mfp-trap-mode=@var{mode}  -mfp-rounding-mode=@var{mode} @gol
+-mtrap-precision=@var{mode}  -mbuild-constants @gol
+-mcpu=@var{cpu-type}  -mtune=@var{cpu-type} @gol
+-mbwx  -mmax  -mfix  -mcix @gol
+-mfloat-vax  -mfloat-ieee @gol
+-mexplicit-relocs  -msmall-data  -mlarge-data @gol
+-msmall-text  -mlarge-text @gol
+-mmemory-latency=@var{time}}
+
+@emph{FR30 Options}
+@gccoptlist{-msmall-model -mno-lsim}
+
+@emph{FRV Options}
+@gccoptlist{-mgpr-32  -mgpr-64  -mfpr-32  -mfpr-64 @gol
+-mhard-float  -msoft-float @gol
+-malloc-cc  -mfixed-cc  -mdword  -mno-dword @gol
+-mdouble  -mno-double @gol
+-mmedia  -mno-media  -mmuladd  -mno-muladd @gol
+-mfdpic  -minline-plt -mgprel-ro  -multilib-library-pic @gol
+-mlinked-fp  -mlong-calls  -malign-labels @gol
+-mlibrary-pic  -macc-4  -macc-8 @gol
+-mpack  -mno-pack  -mno-eflags  -mcond-move  -mno-cond-move @gol
+-moptimize-membar -mno-optimize-membar @gol
+-mscc  -mno-scc  -mcond-exec  -mno-cond-exec @gol
+-mvliw-branch  -mno-vliw-branch @gol
+-mmulti-cond-exec  -mno-multi-cond-exec  -mnested-cond-exec @gol
+-mno-nested-cond-exec  -mtomcat-stats @gol
+-mTLS -mtls @gol
+-mcpu=@var{cpu}}
+
+@emph{GNU/Linux Options}
+@gccoptlist{-mglibc -muclibc -mbionic -mandroid @gol
+-tno-android-cc -tno-android-ld}
+
+@emph{H8/300 Options}
+@gccoptlist{-mrelax  -mh  -ms  -mn  -mexr -mno-exr  -mint32  -malign-300}
+
+@emph{HPPA Options}
+@gccoptlist{-march=@var{architecture-type} @gol
+-mbig-switch  -mdisable-fpregs  -mdisable-indexing @gol
+-mfast-indirect-calls  -mgas  -mgnu-ld   -mhp-ld @gol
+-mfixed-range=@var{register-range} @gol
+-mjump-in-delay -mlinker-opt -mlong-calls @gol
+-mlong-load-store  -mno-big-switch  -mno-disable-fpregs @gol
+-mno-disable-indexing  -mno-fast-indirect-calls  -mno-gas @gol
+-mno-jump-in-delay  -mno-long-load-store @gol
+-mno-portable-runtime  -mno-soft-float @gol
+-mno-space-regs  -msoft-float  -mpa-risc-1-0 @gol
+-mpa-risc-1-1  -mpa-risc-2-0  -mportable-runtime @gol
+-mschedule=@var{cpu-type}  -mspace-regs  -msio  -mwsio @gol
+-munix=@var{unix-std}  -nolibdld  -static  -threads}
+
+@emph{i386 and x86-64 Options}
+@gccoptlist{-mtune=@var{cpu-type}  -march=@var{cpu-type} @gol
+-mfpmath=@var{unit} @gol
+-masm=@var{dialect}  -mno-fancy-math-387 @gol
+-mno-fp-ret-in-387  -msoft-float @gol
+-mno-wide-multiply  -mrtd  -malign-double @gol
+-mpreferred-stack-boundary=@var{num} @gol
+-mincoming-stack-boundary=@var{num} @gol
+-mcld -mcx16 -msahf -mmovbe -mcrc32 @gol
+-mrecip -mrecip=@var{opt} @gol
+-mvzeroupper -mprefer-avx128 @gol
+-mmmx  -msse  -msse2 -msse3 -mssse3 -msse4.1 -msse4.2 -msse4 -mavx @gol
+-mavx2 -maes -mpclmul -mfsgsbase -mrdrnd -mf16c -mfma @gol
+-msse4a -m3dnow -mpopcnt -mabm -mbmi -mtbm -mfma4 -mxop -mlzcnt @gol
+-mbmi2 -mrtm -mlwp -mthreads @gol
+-mno-align-stringops  -minline-all-stringops @gol
+-minline-stringops-dynamically -mstringop-strategy=@var{alg} @gol
+-mpush-args  -maccumulate-outgoing-args  -m128bit-long-double @gol
+-m96bit-long-double -mlong-double-64 -mlong-double-80 @gol
+-mregparm=@var{num}  -msseregparm @gol
+-mveclibabi=@var{type} -mvect8-ret-in-mem @gol
+-mpc32 -mpc64 -mpc80 -mstackrealign @gol
+-momit-leaf-frame-pointer  -mno-red-zone -mno-tls-direct-seg-refs @gol
+-mcmodel=@var{code-model} -mabi=@var{name} -maddress-mode=@var{mode} @gol
+-m32 -m64 -mx32 -mlarge-data-threshold=@var{num} @gol
+-msse2avx -mfentry -m8bit-idiv @gol
+-mavx256-split-unaligned-load -mavx256-split-unaligned-store}
+
+@emph{i386 and x86-64 Windows Options}
+@gccoptlist{-mconsole -mcygwin -mno-cygwin -mdll @gol
+-mnop-fun-dllimport -mthread @gol
+-municode -mwin32 -mwindows -fno-set-stack-executable}
+
+@emph{IA-64 Options}
+@gccoptlist{-mbig-endian  -mlittle-endian  -mgnu-as  -mgnu-ld  -mno-pic @gol
+-mvolatile-asm-stop  -mregister-names  -msdata -mno-sdata @gol
+-mconstant-gp  -mauto-pic  -mfused-madd @gol
+-minline-float-divide-min-latency @gol
+-minline-float-divide-max-throughput @gol
+-mno-inline-float-divide @gol
+-minline-int-divide-min-latency @gol
+-minline-int-divide-max-throughput  @gol
+-mno-inline-int-divide @gol
+-minline-sqrt-min-latency -minline-sqrt-max-throughput @gol
+-mno-inline-sqrt @gol
+-mdwarf2-asm -mearly-stop-bits @gol
+-mfixed-range=@var{register-range} -mtls-size=@var{tls-size} @gol
+-mtune=@var{cpu-type} -milp32 -mlp64 @gol
+-msched-br-data-spec -msched-ar-data-spec -msched-control-spec @gol
+-msched-br-in-data-spec -msched-ar-in-data-spec -msched-in-control-spec @gol
+-msched-spec-ldc -msched-spec-control-ldc @gol
+-msched-prefer-non-data-spec-insns -msched-prefer-non-control-spec-insns @gol
+-msched-stop-bits-after-every-cycle -msched-count-spec-in-critical-path @gol
+-msel-sched-dont-check-control-spec -msched-fp-mem-deps-zero-cost @gol
+-msched-max-memory-insns-hard-limit -msched-max-memory-insns=@var{max-insns}}
+
+@emph{LM32 Options}
+@gccoptlist{-mbarrel-shift-enabled -mdivide-enabled -mmultiply-enabled @gol
+-msign-extend-enabled -muser-enabled}
+
+@emph{M32R/D Options}
+@gccoptlist{-m32r2 -m32rx -m32r @gol
+-mdebug @gol
+-malign-loops -mno-align-loops @gol
+-missue-rate=@var{number} @gol
+-mbranch-cost=@var{number} @gol
+-mmodel=@var{code-size-model-type} @gol
+-msdata=@var{sdata-type} @gol
+-mno-flush-func -mflush-func=@var{name} @gol
+-mno-flush-trap -mflush-trap=@var{number} @gol
+-G @var{num}}
+
+@emph{M32C Options}
+@gccoptlist{-mcpu=@var{cpu} -msim -memregs=@var{number}}
+
+@emph{M680x0 Options}
+@gccoptlist{-march=@var{arch}  -mcpu=@var{cpu}  -mtune=@var{tune}
+-m68000  -m68020  -m68020-40  -m68020-60  -m68030  -m68040 @gol
+-m68060  -mcpu32  -m5200  -m5206e  -m528x  -m5307  -m5407 @gol
+-mcfv4e  -mbitfield  -mno-bitfield  -mc68000  -mc68020 @gol
+-mnobitfield  -mrtd  -mno-rtd  -mdiv  -mno-div  -mshort @gol
+-mno-short  -mhard-float  -m68881  -msoft-float  -mpcrel @gol
+-malign-int  -mstrict-align  -msep-data  -mno-sep-data @gol
+-mshared-library-id=n  -mid-shared-library  -mno-id-shared-library @gol
+-mxgot -mno-xgot}
+
+@emph{MCore Options}
+@gccoptlist{-mhardlit  -mno-hardlit  -mdiv  -mno-div  -mrelax-immediates @gol
+-mno-relax-immediates  -mwide-bitfields  -mno-wide-bitfields @gol
+-m4byte-functions  -mno-4byte-functions  -mcallgraph-data @gol
+-mno-callgraph-data  -mslow-bytes  -mno-slow-bytes  -mno-lsim @gol
+-mlittle-endian  -mbig-endian  -m210  -m340  -mstack-increment}
+
+@emph{MeP Options}
+@gccoptlist{-mabsdiff -mall-opts -maverage -mbased=@var{n} -mbitops @gol
+-mc=@var{n} -mclip -mconfig=@var{name} -mcop -mcop32 -mcop64 -mivc2 @gol
+-mdc -mdiv -meb -mel -mio-volatile -ml -mleadz -mm -mminmax @gol
+-mmult -mno-opts -mrepeat -ms -msatur -msdram -msim -msimnovec -mtf @gol
+-mtiny=@var{n}}
+
+@emph{MicroBlaze Options}
+@gccoptlist{-msoft-float -mhard-float -msmall-divides -mcpu=@var{cpu} @gol
+-mmemcpy -mxl-soft-mul -mxl-soft-div -mxl-barrel-shift @gol
+-mxl-pattern-compare -mxl-stack-check -mxl-gp-opt -mno-clearbss @gol
+-mxl-multiply-high -mxl-float-convert -mxl-float-sqrt @gol
+-mbig-endian -mlittle-endian -mxl-reorder -mxl-mode-@var{app-model}}
+
+@emph{MIPS Options}
+@gccoptlist{-EL  -EB  -march=@var{arch}  -mtune=@var{arch} @gol
+-mips1  -mips2  -mips3  -mips4  -mips32  -mips32r2 @gol
+-mips64  -mips64r2 @gol
+-mips16  -mno-mips16  -mflip-mips16 @gol
+-minterlink-mips16  -mno-interlink-mips16 @gol
+-mabi=@var{abi}  -mabicalls  -mno-abicalls @gol
+-mshared  -mno-shared  -mplt  -mno-plt  -mxgot  -mno-xgot @gol
+-mgp32  -mgp64  -mfp32  -mfp64  -mhard-float  -msoft-float @gol
+-mno-float -msingle-float  -mdouble-float  @gol
+-mdsp  -mno-dsp  -mdspr2  -mno-dspr2 @gol
+-mmcu -mmno-mcu @gol
+-mfpu=@var{fpu-type} @gol
+-msmartmips  -mno-smartmips @gol
+-mpaired-single  -mno-paired-single  -mdmx  -mno-mdmx @gol
+-mips3d  -mno-mips3d  -mmt  -mno-mt  -mllsc  -mno-llsc @gol
+-mlong64  -mlong32  -msym32  -mno-sym32 @gol
+-G@var{num}  -mlocal-sdata  -mno-local-sdata @gol
+-mextern-sdata  -mno-extern-sdata  -mgpopt  -mno-gopt @gol
+-membedded-data  -mno-embedded-data @gol
+-muninit-const-in-rodata  -mno-uninit-const-in-rodata @gol
+-mcode-readable=@var{setting} @gol
+-msplit-addresses  -mno-split-addresses @gol
+-mexplicit-relocs  -mno-explicit-relocs @gol
+-mcheck-zero-division  -mno-check-zero-division @gol
+-mdivide-traps  -mdivide-breaks @gol
+-mmemcpy  -mno-memcpy  -mlong-calls  -mno-long-calls @gol
+-mmad  -mno-mad  -mfused-madd  -mno-fused-madd  -nocpp @gol
+-mfix-24k -mno-fix-24k @gol
+-mfix-r4000  -mno-fix-r4000  -mfix-r4400  -mno-fix-r4400 @gol
+-mfix-r10000 -mno-fix-r10000  -mfix-vr4120  -mno-fix-vr4120 @gol
+-mfix-vr4130  -mno-fix-vr4130  -mfix-sb1  -mno-fix-sb1 @gol
+-mflush-func=@var{func}  -mno-flush-func @gol
+-mbranch-cost=@var{num}  -mbranch-likely  -mno-branch-likely @gol
+-mfp-exceptions -mno-fp-exceptions @gol
+-mvr4130-align -mno-vr4130-align -msynci -mno-synci @gol
+-mrelax-pic-calls -mno-relax-pic-calls -mmcount-ra-address}
+
+@emph{MMIX Options}
+@gccoptlist{-mlibfuncs  -mno-libfuncs  -mepsilon  -mno-epsilon  -mabi=gnu @gol
+-mabi=mmixware  -mzero-extend  -mknuthdiv  -mtoplevel-symbols @gol
+-melf  -mbranch-predict  -mno-branch-predict  -mbase-addresses @gol
+-mno-base-addresses  -msingle-exit  -mno-single-exit}
+
+@emph{MN10300 Options}
+@gccoptlist{-mmult-bug  -mno-mult-bug @gol
+-mno-am33 -mam33 -mam33-2 -mam34 @gol
+-mtune=@var{cpu-type} @gol
+-mreturn-pointer-on-d0 @gol
+-mno-crt0  -mrelax -mliw -msetlb}
+
+@emph{Moxie Options}
+@gccoptlist{-meb -mel -mno-crt0}
+
+@emph{PDP-11 Options}
+@gccoptlist{-mfpu  -msoft-float  -mac0  -mno-ac0  -m40  -m45  -m10 @gol
+-mbcopy  -mbcopy-builtin  -mint32  -mno-int16 @gol
+-mint16  -mno-int32  -mfloat32  -mno-float64 @gol
+-mfloat64  -mno-float32  -mabshi  -mno-abshi @gol
+-mbranch-expensive  -mbranch-cheap @gol
+-munix-asm  -mdec-asm}
+
+@emph{picoChip Options}
+@gccoptlist{-mae=@var{ae_type} -mvliw-lookahead=@var{N} @gol
+-msymbol-as-address -mno-inefficient-warnings}
+
+@emph{PowerPC Options}
+See RS/6000 and PowerPC Options.
+
+@emph{RL78 Options}
+@gccoptlist{-msim -mmul=none -mmul=g13 -mmul=rl78}
+
+@emph{RS/6000 and PowerPC Options}
+@gccoptlist{-mcpu=@var{cpu-type} @gol
+-mtune=@var{cpu-type} @gol
+-mcmodel=@var{code-model} @gol
+-mpowerpc64 @gol
+-maltivec  -mno-altivec @gol
+-mpowerpc-gpopt  -mno-powerpc-gpopt @gol
+-mpowerpc-gfxopt  -mno-powerpc-gfxopt @gol
+-mmfcrf  -mno-mfcrf  -mpopcntb  -mno-popcntb -mpopcntd -mno-popcntd @gol
+-mfprnd  -mno-fprnd @gol
+-mcmpb -mno-cmpb -mmfpgpr -mno-mfpgpr -mhard-dfp -mno-hard-dfp @gol
+-mfull-toc   -mminimal-toc  -mno-fp-in-toc  -mno-sum-in-toc @gol
+-m64  -m32  -mxl-compat  -mno-xl-compat  -mpe @gol
+-malign-power  -malign-natural @gol
+-msoft-float  -mhard-float  -mmultiple  -mno-multiple @gol
+-msingle-float -mdouble-float -msimple-fpu @gol
+-mstring  -mno-string  -mupdate  -mno-update @gol
+-mavoid-indexed-addresses  -mno-avoid-indexed-addresses @gol
+-mfused-madd  -mno-fused-madd  -mbit-align  -mno-bit-align @gol
+-mstrict-align  -mno-strict-align  -mrelocatable @gol
+-mno-relocatable  -mrelocatable-lib  -mno-relocatable-lib @gol
+-mtoc  -mno-toc  -mlittle  -mlittle-endian  -mbig  -mbig-endian @gol
+-mdynamic-no-pic  -maltivec -mswdiv  -msingle-pic-base @gol
+-mprioritize-restricted-insns=@var{priority} @gol
+-msched-costly-dep=@var{dependence_type} @gol
+-minsert-sched-nops=@var{scheme} @gol
+-mcall-sysv  -mcall-netbsd @gol
+-maix-struct-return  -msvr4-struct-return @gol
+-mabi=@var{abi-type} -msecure-plt -mbss-plt @gol
+-mblock-move-inline-limit=@var{num} @gol
+-misel -mno-isel @gol
+-misel=yes  -misel=no @gol
+-mspe -mno-spe @gol
+-mspe=yes  -mspe=no @gol
+-mpaired @gol
+-mgen-cell-microcode -mwarn-cell-microcode @gol
+-mvrsave -mno-vrsave @gol
+-mmulhw -mno-mulhw @gol
+-mdlmzb -mno-dlmzb @gol
+-mfloat-gprs=yes  -mfloat-gprs=no -mfloat-gprs=single -mfloat-gprs=double @gol
+-mprototype  -mno-prototype @gol
+-msim  -mmvme  -mads  -myellowknife  -memb  -msdata @gol
+-msdata=@var{opt}  -mvxworks  -G @var{num}  -pthread @gol
+-mrecip -mrecip=@var{opt} -mno-recip -mrecip-precision @gol
+-mno-recip-precision @gol
+-mveclibabi=@var{type} -mfriz -mno-friz @gol
+-mpointers-to-nested-functions -mno-pointers-to-nested-functions @gol
+-msave-toc-indirect -mno-save-toc-indirect @gol
+-mpower8-fusion -mno-mpower8-fusion -mpower8-vector -mno-power8-vector @gol
+-mcrypto -mno-crypto -mdirect-move -mno-direct-move @gol
+-mquad-memory -mno-quad-memory @gol
+-mquad-memory-atomic -mno-quad-memory-atomic @gol
+-mcompat-align-parm -mno-compat-align-parm}
+
+@emph{RX Options}
+@gccoptlist{-m64bit-doubles  -m32bit-doubles  -fpu  -nofpu@gol
+-mcpu=@gol
+-mbig-endian-data -mlittle-endian-data @gol
+-msmall-data @gol
+-msim  -mno-sim@gol
+-mas100-syntax -mno-as100-syntax@gol
+-mrelax@gol
+-mmax-constant-size=@gol
+-mint-register=@gol
+-mpid@gol
+-mno-warn-multiple-fast-interrupts@gol
+-msave-acc-in-interrupts}
+
+@emph{S/390 and zSeries Options}
+@gccoptlist{-mtune=@var{cpu-type}  -march=@var{cpu-type} @gol
+-mhard-float  -msoft-float  -mhard-dfp -mno-hard-dfp @gol
+-mlong-double-64 -mlong-double-128 @gol
+-mbackchain  -mno-backchain -mpacked-stack  -mno-packed-stack @gol
+-msmall-exec  -mno-small-exec  -mmvcle -mno-mvcle @gol
+-m64  -m31  -mdebug  -mno-debug  -mesa  -mzarch @gol
+-mtpf-trace -mno-tpf-trace  -mfused-madd  -mno-fused-madd @gol
+-mwarn-framesize  -mwarn-dynamicstack  -mstack-size -mstack-guard @gol
+-mhotpatch[=@var{halfwords}] -mno-hotpatch}
+
+@emph{Score Options}
+@gccoptlist{-meb -mel @gol
+-mnhwloop @gol
+-muls @gol
+-mmac @gol
+-mscore5 -mscore5u -mscore7 -mscore7d}
+
+@emph{SH Options}
+@gccoptlist{-m1  -m2  -m2e @gol
+-m2a-nofpu -m2a-single-only -m2a-single -m2a @gol
+-m3  -m3e @gol
+-m4-nofpu  -m4-single-only  -m4-single  -m4 @gol
+-m4a-nofpu -m4a-single-only -m4a-single -m4a -m4al @gol
+-m5-64media  -m5-64media-nofpu @gol
+-m5-32media  -m5-32media-nofpu @gol
+-m5-compact  -m5-compact-nofpu @gol
+-mb  -ml  -mdalign  -mrelax @gol
+-mbigtable -mfmovd -mhitachi -mrenesas -mno-renesas -mnomacsave @gol
+-mieee -mno-ieee -mbitops  -misize  -minline-ic_invalidate -mpadstruct @gol
+-mspace -mprefergot  -musermode -multcost=@var{number} -mdiv=@var{strategy} @gol
+-mdivsi3_libfunc=@var{name} -mfixed-range=@var{register-range} @gol
+-mindexed-addressing -mgettrcost=@var{number} -mpt-fixed @gol
+-maccumulate-outgoing-args -minvalid-symbols @gol
+-matomic-model=@var{atomic-model} @gol
+-mbranch-cost=@var{num} -mzdcbranch -mno-zdcbranch -mcbranchdi -mcmpeqdi @gol
+-mfused-madd -mno-fused-madd -mfsca -mno-fsca -mfsrra -mno-fsrra @gol
+-mpretend-cmove -mtas}
+
+@emph{Solaris 2 Options}
+@gccoptlist{-mimpure-text  -mno-impure-text @gol
+-pthreads -pthread}
+
+@emph{SPARC Options}
+@gccoptlist{-mcpu=@var{cpu-type} @gol
+-mtune=@var{cpu-type} @gol
+-mcmodel=@var{code-model} @gol
+-mmemory-model=@var{mem-model} @gol
+-m32  -m64  -mapp-regs  -mno-app-regs @gol
+-mfaster-structs  -mno-faster-structs  -mflat  -mno-flat @gol
+-mfpu  -mno-fpu  -mhard-float  -msoft-float @gol
+-mhard-quad-float  -msoft-quad-float @gol
+-mstack-bias  -mno-stack-bias @gol
+-munaligned-doubles  -mno-unaligned-doubles @gol
+-muser-mode  -mno-user-mode @gol
+-mv8plus  -mno-v8plus  -mvis  -mno-vis @gol
+-mvis2  -mno-vis2  -mvis3  -mno-vis3 @gol
+-mcbcond -mno-cbcond @gol
+-mfmaf  -mno-fmaf  -mpopc  -mno-popc @gol
+-mfix-at697f -mfix-ut699}
+
+@emph{SPU Options}
+@gccoptlist{-mwarn-reloc -merror-reloc @gol
+-msafe-dma -munsafe-dma @gol
+-mbranch-hints @gol
+-msmall-mem -mlarge-mem -mstdmain @gol
+-mfixed-range=@var{register-range} @gol
+-mea32 -mea64 @gol
+-maddress-space-conversion -mno-address-space-conversion @gol
+-mcache-size=@var{cache-size} @gol
+-matomic-updates -mno-atomic-updates}
+
+@emph{System V Options}
+@gccoptlist{-Qy  -Qn  -YP,@var{paths}  -Ym,@var{dir}}
+
+@emph{TILE-Gx Options}
+@gccoptlist{-mcpu=@var{cpu} -m32 -m64 -mcmodel=@var{code-model}}
+
+@emph{TILEPro Options}
+@gccoptlist{-mcpu=@var{cpu} -m32}
+
+@emph{V850 Options}
+@gccoptlist{-mlong-calls  -mno-long-calls  -mep  -mno-ep @gol
+-mprolog-function  -mno-prolog-function  -mspace @gol
+-mtda=@var{n}  -msda=@var{n}  -mzda=@var{n} @gol
+-mapp-regs  -mno-app-regs @gol
+-mdisable-callt  -mno-disable-callt @gol
+-mv850e2v3 -mv850e2 -mv850e1 -mv850es @gol
+-mv850e -mv850 -mv850e3v5 @gol
+-mloop @gol
+-mrelax @gol
+-mlong-jumps @gol
+-msoft-float @gol
+-mhard-float @gol
+-mgcc-abi @gol
+-mrh850-abi @gol
+-mbig-switch}
+
+@emph{VAX Options}
+@gccoptlist{-mg  -mgnu  -munix}
+
+@emph{VMS Options}
+@gccoptlist{-mvms-return-codes -mdebug-main=@var{prefix} -mmalloc64 @gol
+-mpointer-size=@var{size}}
+
+@emph{VxWorks Options}
+@gccoptlist{-mrtp  -non-static  -Bstatic  -Bdynamic @gol
+-Xbind-lazy  -Xbind-now}
+
+@emph{x86-64 Options}
+See i386 and x86-64 Options.
+
+@emph{Xstormy16 Options}
+@gccoptlist{-msim}
+
+@emph{Xtensa Options}
+@gccoptlist{-mconst16 -mno-const16 @gol
+-mfused-madd  -mno-fused-madd @gol
+-mforce-no-pic @gol
+-mserialize-volatile  -mno-serialize-volatile @gol
+-mtext-section-literals  -mno-text-section-literals @gol
+-mtarget-align  -mno-target-align @gol
+-mlongcalls  -mno-longcalls}
+
+@emph{zSeries Options}
+See S/390 and zSeries Options.
+
+@item Code Generation Options
+@xref{Code Gen Options,,Options for Code Generation Conventions}.
+@gccoptlist{-fcall-saved-@var{reg}  -fcall-used-@var{reg} @gol
+-ffixed-@var{reg}  -fexceptions @gol
+-fnon-call-exceptions  -fdelete-dead-exceptions  -funwind-tables @gol
+-fasynchronous-unwind-tables @gol
+-finhibit-size-directive  -finstrument-functions @gol
+-finstrument-functions-exclude-function-list=@var{sym},@var{sym},@dots{} @gol
+-finstrument-functions-exclude-file-list=@var{file},@var{file},@dots{} @gol
+-fno-common  -fno-ident @gol
+-fpcc-struct-return  -fpic  -fPIC -fpie -fPIE @gol
+-fno-jump-tables @gol
+-frecord-gcc-switches @gol
+-freg-struct-return  -fshort-enums @gol
+-fshort-double  -fshort-wchar @gol
+-fverbose-asm  -fpack-struct[=@var{n}]  -fstack-check @gol
+-fstack-limit-register=@var{reg}  -fstack-limit-symbol=@var{sym} @gol
+-fno-stack-limit -fsplit-stack @gol
+-fleading-underscore  -ftls-model=@var{model} @gol
+-fstack-reuse=@var{reuse_level} @gol
+-ftrapv  -fwrapv  -fbounds-check @gol
+-fvisibility -fstrict-volatile-bitfields -fsync-libcalls}
+@end table
+
+@menu
+* Overall Options::     Controlling the kind of output:
+                        an executable, object files, assembler files,
+                        or preprocessed source.
+* C Dialect Options::   Controlling the variant of C language compiled.
+* C++ Dialect Options:: Variations on C++.
+* Objective-C and Objective-C++ Dialect Options:: Variations on Objective-C
+                        and Objective-C++.
+* Language Independent Options:: Controlling how diagnostics should be
+                        formatted.
+* Warning Options::     How picky should the compiler be?
+* Debugging Options::   Symbol tables, measurements, and debugging dumps.
+* Optimize Options::    How much optimization?
+* Preprocessor Options:: Controlling header files and macro definitions.
+                         Also, getting dependency information for Make.
+* Assembler Options::   Passing options to the assembler.
+* Link Options::        Specifying libraries and so on.
+* Directory Options::   Where to find header files and libraries.
+                        Where to find the compiler executable files.
+* Spec Files::          How to pass switches to sub-processes.
+* Target Options::      Running a cross-compiler, or an old version of GCC.
+@end menu
+
+@node Overall Options
+@section Options Controlling the Kind of Output
+
+Compilation can involve up to four stages: preprocessing, compilation
+proper, assembly and linking, always in that order.  GCC is capable of
+preprocessing and compiling several files either into several
+assembler input files, or into one assembler input file; then each
+assembler input file produces an object file, and linking combines all
+the object files (those newly compiled, and those specified as input)
+into an executable file.
+
+@cindex file name suffix
+For any given input file, the file name suffix determines what kind of
+compilation is done:
+
+@table @gcctabopt
+@item @var{file}.c
+C source code that must be preprocessed.
+
+@item @var{file}.i
+C source code that should not be preprocessed.
+
+@item @var{file}.ii
+C++ source code that should not be preprocessed.
+
+@item @var{file}.m
+Objective-C source code.  Note that you must link with the @file{libobjc}
+library to make an Objective-C program work.
+
+@item @var{file}.mi
+Objective-C source code that should not be preprocessed.
+
+@item @var{file}.mm
+@itemx @var{file}.M
+Objective-C++ source code.  Note that you must link with the @file{libobjc}
+library to make an Objective-C++ program work.  Note that @samp{.M} refers
+to a literal capital M@.
+
+@item @var{file}.mii
+Objective-C++ source code that should not be preprocessed.
+
+@item @var{file}.h
+C, C++, Objective-C or Objective-C++ header file to be turned into a
+precompiled header (default), or C, C++ header file to be turned into an
+Ada spec (via the @option{-fdump-ada-spec} switch).
+
+@item @var{file}.cc
+@itemx @var{file}.cp
+@itemx @var{file}.cxx
+@itemx @var{file}.cpp
+@itemx @var{file}.CPP
+@itemx @var{file}.c++
+@itemx @var{file}.C
+C++ source code that must be preprocessed.  Note that in @samp{.cxx},
+the last two letters must both be literally @samp{x}.  Likewise,
+@samp{.C} refers to a literal capital C@.
+
+@item @var{file}.mm
+@itemx @var{file}.M
+Objective-C++ source code that must be preprocessed.
+
+@item @var{file}.mii
+Objective-C++ source code that should not be preprocessed.
+
+@item @var{file}.hh
+@itemx @var{file}.H
+@itemx @var{file}.hp
+@itemx @var{file}.hxx
+@itemx @var{file}.hpp
+@itemx @var{file}.HPP
+@itemx @var{file}.h++
+@itemx @var{file}.tcc
+C++ header file to be turned into a precompiled header or Ada spec.
+
+@item @var{file}.f
+@itemx @var{file}.for
+@itemx @var{file}.ftn
+Fixed form Fortran source code that should not be preprocessed.
+
+@item @var{file}.F
+@itemx @var{file}.FOR
+@itemx @var{file}.fpp
+@itemx @var{file}.FPP
+@itemx @var{file}.FTN
+Fixed form Fortran source code that must be preprocessed (with the traditional
+preprocessor).
+
+@item @var{file}.f90
+@itemx @var{file}.f95
+@itemx @var{file}.f03
+@itemx @var{file}.f08
+Free form Fortran source code that should not be preprocessed.
+
+@item @var{file}.F90
+@itemx @var{file}.F95
+@itemx @var{file}.F03
+@itemx @var{file}.F08
+Free form Fortran source code that must be preprocessed (with the
+traditional preprocessor).
+
+@item @var{file}.go
+Go source code.
+
+@c FIXME: Descriptions of Java file types.
+@c @var{file}.java
+@c @var{file}.class
+@c @var{file}.zip
+@c @var{file}.jar
+
+@item @var{file}.ads
+Ada source code file that contains a library unit declaration (a
+declaration of a package, subprogram, or generic, or a generic
+instantiation), or a library unit renaming declaration (a package,
+generic, or subprogram renaming declaration).  Such files are also
+called @dfn{specs}.
+
+@item @var{file}.adb
+Ada source code file containing a library unit body (a subprogram or
+package body).  Such files are also called @dfn{bodies}.
+
+@c GCC also knows about some suffixes for languages not yet included:
+@c Pascal:
+@c @var{file}.p
+@c @var{file}.pas
+@c Ratfor:
+@c @var{file}.r
+
+@item @var{file}.s
+Assembler code.
+
+@item @var{file}.S
+@itemx @var{file}.sx
+Assembler code that must be preprocessed.
+
+@item @var{other}
+An object file to be fed straight into linking.
+Any file name with no recognized suffix is treated this way.
+@end table
+
+@opindex x
+You can specify the input language explicitly with the @option{-x} option:
+
+@table @gcctabopt
+@item -x @var{language}
+Specify explicitly the @var{language} for the following input files
+(rather than letting the compiler choose a default based on the file
+name suffix).  This option applies to all following input files until
+the next @option{-x} option.  Possible values for @var{language} are:
+@smallexample
+c  c-header  cpp-output
+c++  c++-header  c++-cpp-output
+objective-c  objective-c-header  objective-c-cpp-output
+objective-c++ objective-c++-header objective-c++-cpp-output
+assembler  assembler-with-cpp
+ada
+f77  f77-cpp-input f95  f95-cpp-input
+go
+java
+@end smallexample
+
+@item -x none
+Turn off any specification of a language, so that subsequent files are
+handled according to their file name suffixes (as they are if @option{-x}
+has not been used at all).
+
+@item -pass-exit-codes
+@opindex pass-exit-codes
+Normally the @command{gcc} program exits with the code of 1 if any
+phase of the compiler returns a non-success return code.  If you specify
+@option{-pass-exit-codes}, the @command{gcc} program instead returns with
+the numerically highest error produced by any phase returning an error
+indication.  The C, C++, and Fortran front ends return 4 if an internal
+compiler error is encountered.
+@end table
+
+If you only want some of the stages of compilation, you can use
+@option{-x} (or filename suffixes) to tell @command{gcc} where to start, and
+one of the options @option{-c}, @option{-S}, or @option{-E} to say where
+@command{gcc} is to stop.  Note that some combinations (for example,
+@samp{-x cpp-output -E}) instruct @command{gcc} to do nothing at all.
+
+@table @gcctabopt
+@item -c
+@opindex c
+Compile or assemble the source files, but do not link.  The linking
+stage simply is not done.  The ultimate output is in the form of an
+object file for each source file.
+
+By default, the object file name for a source file is made by replacing
+the suffix @samp{.c}, @samp{.i}, @samp{.s}, etc., with @samp{.o}.
+
+Unrecognized input files, not requiring compilation or assembly, are
+ignored.
+
+@item -S
+@opindex S
+Stop after the stage of compilation proper; do not assemble.  The output
+is in the form of an assembler code file for each non-assembler input
+file specified.
+
+By default, the assembler file name for a source file is made by
+replacing the suffix @samp{.c}, @samp{.i}, etc., with @samp{.s}.
+
+Input files that don't require compilation are ignored.
+
+@item -E
+@opindex E
+Stop after the preprocessing stage; do not run the compiler proper.  The
+output is in the form of preprocessed source code, which is sent to the
+standard output.
+
+Input files that don't require preprocessing are ignored.
+
+@cindex output file option
+@item -o @var{file}
+@opindex o
+Place output in file @var{file}.  This applies to whatever
+sort of output is being produced, whether it be an executable file,
+an object file, an assembler file or preprocessed C code.
+
+If @option{-o} is not specified, the default is to put an executable
+file in @file{a.out}, the object file for
+@file{@var{source}.@var{suffix}} in @file{@var{source}.o}, its
+assembler file in @file{@var{source}.s}, a precompiled header file in
+@file{@var{source}.@var{suffix}.gch}, and all preprocessed C source on
+standard output.
+
+@item -v
+@opindex v
+Print (on standard error output) the commands executed to run the stages
+of compilation.  Also print the version number of the compiler driver
+program and of the preprocessor and the compiler proper.
+
+@item -###
+@opindex ###
+Like @option{-v} except the commands are not executed and arguments
+are quoted unless they contain only alphanumeric characters or @code{./-_}.
+This is useful for shell scripts to capture the driver-generated command lines.
+
+@item -pipe
+@opindex pipe
+Use pipes rather than temporary files for communication between the
+various stages of compilation.  This fails to work on some systems where
+the assembler is unable to read from a pipe; but the GNU assembler has
+no trouble.
+
+@item --help
+@opindex help
+Print (on the standard output) a description of the command-line options
+understood by @command{gcc}.  If the @option{-v} option is also specified
+then @option{--help} is also passed on to the various processes
+invoked by @command{gcc}, so that they can display the command-line options
+they accept.  If the @option{-Wextra} option has also been specified
+(prior to the @option{--help} option), then command-line options that
+have no documentation associated with them are also displayed.
+
+@item --target-help
+@opindex target-help
+Print (on the standard output) a description of target-specific command-line
+options for each tool.  For some targets extra target-specific
+information may also be printed.
+
+@item --help=@{@var{class}@r{|[}^@r{]}@var{qualifier}@}@r{[},@dots{}@r{]}
+Print (on the standard output) a description of the command-line
+options understood by the compiler that fit into all specified classes
+and qualifiers.  These are the supported classes:
+
+@table @asis
+@item @samp{optimizers}
+Display all of the optimization options supported by the
+compiler.
+
+@item @samp{warnings}
+Display all of the options controlling warning messages
+produced by the compiler.
+
+@item @samp{target}
+Display target-specific options.  Unlike the
+@option{--target-help} option however, target-specific options of the
+linker and assembler are not displayed.  This is because those
+tools do not currently support the extended @option{--help=} syntax.
+
+@item @samp{params}
+Display the values recognized by the @option{--param}
+option.
+
+@item @var{language}
+Display the options supported for @var{language}, where
+@var{language} is the name of one of the languages supported in this
+version of GCC@.
+
+@item @samp{common}
+Display the options that are common to all languages.
+@end table
+
+These are the supported qualifiers:
+
+@table @asis
+@item @samp{undocumented}
+Display only those options that are undocumented.
+
+@item @samp{joined}
+Display options taking an argument that appears after an equal
+sign in the same continuous piece of text, such as:
+@samp{--help=target}.
+
+@item @samp{separate}
+Display options taking an argument that appears as a separate word
+following the original option, such as: @samp{-o output-file}.
+@end table
+
+Thus for example to display all the undocumented target-specific
+switches supported by the compiler, use:
+
+@smallexample
+--help=target,undocumented
+@end smallexample
+
+The sense of a qualifier can be inverted by prefixing it with the
+@samp{^} character, so for example to display all binary warning
+options (i.e., ones that are either on or off and that do not take an
+argument) that have a description, use:
+
+@smallexample
+--help=warnings,^joined,^undocumented
+@end smallexample
+
+The argument to @option{--help=} should not consist solely of inverted
+qualifiers.
+
+Combining several classes is possible, although this usually
+restricts the output so much that there is nothing to display.  One
+case where it does work, however, is when one of the classes is
+@var{target}.  For example, to display all the target-specific
+optimization options, use:
+
+@smallexample
+--help=target,optimizers
+@end smallexample
+
+The @option{--help=} option can be repeated on the command line.  Each
+successive use displays its requested class of options, skipping
+those that have already been displayed.
+
+If the @option{-Q} option appears on the command line before the
+@option{--help=} option, then the descriptive text displayed by
+@option{--help=} is changed.  Instead of describing the displayed
+options, an indication is given as to whether the option is enabled,
+disabled or set to a specific value (assuming that the compiler
+knows this at the point where the @option{--help=} option is used).
+
+Here is a truncated example from the ARM port of @command{gcc}:
+
+@smallexample
+  % gcc -Q -mabi=2 --help=target -c
+  The following options are target specific:
+  -mabi=                                2
+  -mabort-on-noreturn                   [disabled]
+  -mapcs                                [disabled]
+@end smallexample
+
+The output is sensitive to the effects of previous command-line
+options, so for example it is possible to find out which optimizations
+are enabled at @option{-O2} by using:
+
+@smallexample
+-Q -O2 --help=optimizers
+@end smallexample
+
+Alternatively you can discover which binary optimizations are enabled
+by @option{-O3} by using:
+
+@smallexample
+gcc -c -Q -O3 --help=optimizers > /tmp/O3-opts
+gcc -c -Q -O2 --help=optimizers > /tmp/O2-opts
+diff /tmp/O2-opts /tmp/O3-opts | grep enabled
+@end smallexample
+
+@item -no-canonical-prefixes
+@opindex no-canonical-prefixes
+Do not expand any symbolic links, resolve references to @samp{/../}
+or @samp{/./}, or make the path absolute when generating a relative
+prefix.
+
+@item --version
+@opindex version
+Display the version number and copyrights of the invoked GCC@.
+
+@item -wrapper
+@opindex wrapper
+Invoke all subcommands under a wrapper program.  The name of the
+wrapper program and its parameters are passed as a comma separated
+list.
+
+@smallexample
+gcc -c t.c -wrapper gdb,--args
+@end smallexample
+
+@noindent
+This invokes all subprograms of @command{gcc} under
+@samp{gdb --args}, thus the invocation of @command{cc1} is
+@samp{gdb --args cc1 @dots{}}.
+
+@item -fplugin=@var{name}.so
+Load the plugin code in file @var{name}.so, assumed to be a
+shared object to be dlopen'd by the compiler.  The base name of
+the shared object file is used to identify the plugin for the
+purposes of argument parsing (See
+@option{-fplugin-arg-@var{name}-@var{key}=@var{value}} below).
+Each plugin should define the callback functions specified in the
+Plugins API.
+
+@item -fplugin-arg-@var{name}-@var{key}=@var{value}
+Define an argument called @var{key} with a value of @var{value}
+for the plugin called @var{name}.
+
+@item -fdump-ada-spec@r{[}-slim@r{]}
+@opindex fdump-ada-spec
+For C and C++ source and include files, generate corresponding Ada specs.
+@xref{Generating Ada Bindings for C and C++ headers,,, gnat_ugn,
+GNAT User's Guide}, which provides detailed documentation on this feature.
+
+@item -fada-spec-parent=@var{unit}
+@opindex fada-spec-parent
+In conjunction with @option{-fdump-ada-spec@r{[}-slim@r{]}} above, generate
+Ada specs as child units of parent @var{unit}.
+
+@item -fdump-go-spec=@var{file}
+@opindex fdump-go-spec
+For input files in any language, generate corresponding Go
+declarations in @var{file}.  This generates Go @code{const},
+@code{type}, @code{var}, and @code{func} declarations which may be a
+useful way to start writing a Go interface to code written in some
+other language.
+
+@include @value{srcdir}/../libiberty/at-file.texi
+@end table
+
+@node Invoking G++
+@section Compiling C++ Programs
+
+@cindex suffixes for C++ source
+@cindex C++ source file suffixes
+C++ source files conventionally use one of the suffixes @samp{.C},
+@samp{.cc}, @samp{.cpp}, @samp{.CPP}, @samp{.c++}, @samp{.cp}, or
+@samp{.cxx}; C++ header files often use @samp{.hh}, @samp{.hpp},
+@samp{.H}, or (for shared template code) @samp{.tcc}; and
+preprocessed C++ files use the suffix @samp{.ii}.  GCC recognizes
+files with these names and compiles them as C++ programs even if you
+call the compiler the same way as for compiling C programs (usually
+with the name @command{gcc}).
+
+@findex g++
+@findex c++
+However, the use of @command{gcc} does not add the C++ library.
+@command{g++} is a program that calls GCC and automatically specifies linking
+against the C++ library.  It treats @samp{.c},
+@samp{.h} and @samp{.i} files as C++ source files instead of C source
+files unless @option{-x} is used.  This program is also useful when
+precompiling a C header file with a @samp{.h} extension for use in C++
+compilations.  On many systems, @command{g++} is also installed with
+the name @command{c++}.
+
+@cindex invoking @command{g++}
+When you compile C++ programs, you may specify many of the same
+command-line options that you use for compiling programs in any
+language; or command-line options meaningful for C and related
+languages; or options that are meaningful only for C++ programs.
+@xref{C Dialect Options,,Options Controlling C Dialect}, for
+explanations of options for languages related to C@.
+@xref{C++ Dialect Options,,Options Controlling C++ Dialect}, for
+explanations of options that are meaningful only for C++ programs.
+
+@node C Dialect Options
+@section Options Controlling C Dialect
+@cindex dialect options
+@cindex language dialect options
+@cindex options, dialect
+
+The following options control the dialect of C (or languages derived
+from C, such as C++, Objective-C and Objective-C++) that the compiler
+accepts:
+
+@table @gcctabopt
+@cindex ANSI support
+@cindex ISO support
+@item -ansi
+@opindex ansi
+In C mode, this is equivalent to @option{-std=c90}. In C++ mode, it is
+equivalent to @option{-std=c++98}.
+
+This turns off certain features of GCC that are incompatible with ISO
+C90 (when compiling C code), or of standard C++ (when compiling C++ code),
+such as the @code{asm} and @code{typeof} keywords, and
+predefined macros such as @code{unix} and @code{vax} that identify the
+type of system you are using.  It also enables the undesirable and
+rarely used ISO trigraph feature.  For the C compiler,
+it disables recognition of C++ style @samp{//} comments as well as
+the @code{inline} keyword.
+
+The alternate keywords @code{__asm__}, @code{__extension__},
+@code{__inline__} and @code{__typeof__} continue to work despite
+@option{-ansi}.  You would not want to use them in an ISO C program, of
+course, but it is useful to put them in header files that might be included
+in compilations done with @option{-ansi}.  Alternate predefined macros
+such as @code{__unix__} and @code{__vax__} are also available, with or
+without @option{-ansi}.
+
+The @option{-ansi} option does not cause non-ISO programs to be
+rejected gratuitously.  For that, @option{-Wpedantic} is required in
+addition to @option{-ansi}.  @xref{Warning Options}.
+
+The macro @code{__STRICT_ANSI__} is predefined when the @option{-ansi}
+option is used.  Some header files may notice this macro and refrain
+from declaring certain functions or defining certain macros that the
+ISO standard doesn't call for; this is to avoid interfering with any
+programs that might use these names for other things.
+
+Functions that are normally built in but do not have semantics
+defined by ISO C (such as @code{alloca} and @code{ffs}) are not built-in
+functions when @option{-ansi} is used.  @xref{Other Builtins,,Other
+built-in functions provided by GCC}, for details of the functions
+affected.
+
+@item -std=
+@opindex std
+Determine the language standard. @xref{Standards,,Language Standards
+Supported by GCC}, for details of these standard versions.  This option
+is currently only supported when compiling C or C++.
+
+The compiler can accept several base standards, such as @samp{c90} or
+@samp{c++98}, and GNU dialects of those standards, such as
+@samp{gnu90} or @samp{gnu++98}.  When a base standard is specified, the
+compiler accepts all programs following that standard plus those
+using GNU extensions that do not contradict it.  For example,
+@option{-std=c90} turns off certain features of GCC that are
+incompatible with ISO C90, such as the @code{asm} and @code{typeof}
+keywords, but not other GNU extensions that do not have a meaning in
+ISO C90, such as omitting the middle term of a @code{?:}
+expression. On the other hand, when a GNU dialect of a standard is
+specified, all features supported by the compiler are enabled, even when
+those features change the meaning of the base standard.  As a result, some
+strict-conforming programs may be rejected.  The particular standard
+is used by @option{-Wpedantic} to identify which features are GNU
+extensions given that version of the standard. For example
+@option{-std=gnu90 -Wpedantic} warns about C++ style @samp{//}
+comments, while @option{-std=gnu99 -Wpedantic} does not.
+
+A value for this option must be provided; possible values are
+
+@table @samp
+@item c90
+@itemx c89
+@itemx iso9899:1990
+Support all ISO C90 programs (certain GNU extensions that conflict
+with ISO C90 are disabled). Same as @option{-ansi} for C code.
+
+@item iso9899:199409
+ISO C90 as modified in amendment 1.
+
+@item c99
+@itemx c9x
+@itemx iso9899:1999
+@itemx iso9899:199x
+ISO C99.  Note that this standard is not yet fully supported; see
+@w{@uref{http://gcc.gnu.org/c99status.html}} for more information.  The
+names @samp{c9x} and @samp{iso9899:199x} are deprecated.
+
+@item c11
+@itemx c1x
+@itemx iso9899:2011
+ISO C11, the 2011 revision of the ISO C standard.
+Support is incomplete and experimental.  The name @samp{c1x} is
+deprecated.
+
+@item gnu90
+@itemx gnu89
+GNU dialect of ISO C90 (including some C99 features). This
+is the default for C code.
+
+@item gnu99
+@itemx gnu9x
+GNU dialect of ISO C99.  When ISO C99 is fully implemented in GCC,
+this will become the default.  The name @samp{gnu9x} is deprecated.
+
+@item gnu11
+@itemx gnu1x
+GNU dialect of ISO C11.  Support is incomplete and experimental.  The
+name @samp{gnu1x} is deprecated.
+
+@item c++98
+@itemx c++03
+The 1998 ISO C++ standard plus the 2003 technical corrigendum and some
+additional defect reports. Same as @option{-ansi} for C++ code.
+
+@item gnu++98
+@itemx gnu++03
+GNU dialect of @option{-std=c++98}.  This is the default for
+C++ code.
+
+@item c++11
+@itemx c++0x
+The 2011 ISO C++ standard plus amendments.  Support for C++11 is still
+experimental, and may change in incompatible ways in future releases.
+The name @samp{c++0x} is deprecated.
+
+@item gnu++11
+@itemx gnu++0x
+GNU dialect of @option{-std=c++11}. Support for C++11 is still
+experimental, and may change in incompatible ways in future releases.
+The name @samp{gnu++0x} is deprecated.
+
+@item c++1y
+The next revision of the ISO C++ standard, tentatively planned for
+2017.  Support is highly experimental, and will almost certainly
+change in incompatible ways in future releases.
+
+@item gnu++1y
+GNU dialect of @option{-std=c++1y}.  Support is highly experimental,
+and will almost certainly change in incompatible ways in future
+releases.
+@end table
+
+@item -fgnu89-inline
+@opindex fgnu89-inline
+The option @option{-fgnu89-inline} tells GCC to use the traditional
+GNU semantics for @code{inline} functions when in C99 mode.
+@xref{Inline,,An Inline Function is As Fast As a Macro}.  This option
+is accepted and ignored by GCC versions 4.1.3 up to but not including
+4.3.  In GCC versions 4.3 and later it changes the behavior of GCC in
+C99 mode.  Using this option is roughly equivalent to adding the
+@code{gnu_inline} function attribute to all inline functions
+(@pxref{Function Attributes}).
+
+The option @option{-fno-gnu89-inline} explicitly tells GCC to use the
+C99 semantics for @code{inline} when in C99 or gnu99 mode (i.e., it
+specifies the default behavior).  This option was first supported in
+GCC 4.3.  This option is not supported in @option{-std=c90} or
+@option{-std=gnu90} mode.
+
+The preprocessor macros @code{__GNUC_GNU_INLINE__} and
+@code{__GNUC_STDC_INLINE__} may be used to check which semantics are
+in effect for @code{inline} functions.  @xref{Common Predefined
+Macros,,,cpp,The C Preprocessor}.
+
+@item -aux-info @var{filename}
+@opindex aux-info
+Output to the given filename prototyped declarations for all functions
+declared and/or defined in a translation unit, including those in header
+files.  This option is silently ignored in any language other than C@.
+
+Besides declarations, the file indicates, in comments, the origin of
+each declaration (source file and line), whether the declaration was
+implicit, prototyped or unprototyped (@samp{I}, @samp{N} for new or
+@samp{O} for old, respectively, in the first character after the line
+number and the colon), and whether it came from a declaration or a
+definition (@samp{C} or @samp{F}, respectively, in the following
+character).  In the case of function definitions, a K&R-style list of
+arguments followed by their declarations is also provided, inside
+comments, after the declaration.
+
+@item -fallow-parameterless-variadic-functions
+Accept variadic functions without named parameters.
+
+Although it is possible to define such a function, this is not very
+useful as it is not possible to read the arguments.  This is only
+supported for C as this construct is allowed by C++.
+
+@item -fno-asm
+@opindex fno-asm
+Do not recognize @code{asm}, @code{inline} or @code{typeof} as a
+keyword, so that code can use these words as identifiers.  You can use
+the keywords @code{__asm__}, @code{__inline__} and @code{__typeof__}
+instead.  @option{-ansi} implies @option{-fno-asm}.
+
+In C++, this switch only affects the @code{typeof} keyword, since
+@code{asm} and @code{inline} are standard keywords.  You may want to
+use the @option{-fno-gnu-keywords} flag instead, which has the same
+effect.  In C99 mode (@option{-std=c99} or @option{-std=gnu99}), this
+switch only affects the @code{asm} and @code{typeof} keywords, since
+@code{inline} is a standard keyword in ISO C99.
+
+@item -fno-builtin
+@itemx -fno-builtin-@var{function}
+@opindex fno-builtin
+@cindex built-in functions
+Don't recognize built-in functions that do not begin with
+@samp{__builtin_} as prefix.  @xref{Other Builtins,,Other built-in
+functions provided by GCC}, for details of the functions affected,
+including those which are not built-in functions when @option{-ansi} or
+@option{-std} options for strict ISO C conformance are used because they
+do not have an ISO standard meaning.
+
+GCC normally generates special code to handle certain built-in functions
+more efficiently; for instance, calls to @code{alloca} may become single
+instructions which adjust the stack directly, and calls to @code{memcpy}
+may become inline copy loops.  The resulting code is often both smaller
+and faster, but since the function calls no longer appear as such, you
+cannot set a breakpoint on those calls, nor can you change the behavior
+of the functions by linking with a different library.  In addition,
+when a function is recognized as a built-in function, GCC may use
+information about that function to warn about problems with calls to
+that function, or to generate more efficient code, even if the
+resulting code still contains calls to that function.  For example,
+warnings are given with @option{-Wformat} for bad calls to
+@code{printf} when @code{printf} is built in and @code{strlen} is
+known not to modify global memory.
+
+With the @option{-fno-builtin-@var{function}} option
+only the built-in function @var{function} is
+disabled.  @var{function} must not begin with @samp{__builtin_}.  If a
+function is named that is not built-in in this version of GCC, this
+option is ignored.  There is no corresponding
+@option{-fbuiltin-@var{function}} option; if you wish to enable
+built-in functions selectively when using @option{-fno-builtin} or
+@option{-ffreestanding}, you may define macros such as:
+
+@smallexample
+#define abs(n)          __builtin_abs ((n))
+#define strcpy(d, s)    __builtin_strcpy ((d), (s))
+@end smallexample
+
+@item -fhosted
+@opindex fhosted
+@cindex hosted environment
+
+Assert that compilation targets a hosted environment.  This implies
+@option{-fbuiltin}.  A hosted environment is one in which the
+entire standard library is available, and in which @code{main} has a return
+type of @code{int}.  Examples are nearly everything except a kernel.
+This is equivalent to @option{-fno-freestanding}.
+
+@item -ffreestanding
+@opindex ffreestanding
+@cindex hosted environment
+
+Assert that compilation targets a freestanding environment.  This
+implies @option{-fno-builtin}.  A freestanding environment
+is one in which the standard library may not exist, and program startup may
+not necessarily be at @code{main}.  The most obvious example is an OS kernel.
+This is equivalent to @option{-fno-hosted}.
+
+@xref{Standards,,Language Standards Supported by GCC}, for details of
+freestanding and hosted environments.
+
+@item -fopenmp
+@opindex fopenmp
+@cindex OpenMP parallel
+Enable handling of OpenMP directives @code{#pragma omp} in C/C++ and
+@code{!$omp} in Fortran.  When @option{-fopenmp} is specified, the
+compiler generates parallel code according to the OpenMP Application
+Program Interface v3.0 @w{@uref{http://www.openmp.org/}}.  This option
+implies @option{-pthread}, and thus is only supported on targets that
+have support for @option{-pthread}.
+
+@item -fgnu-tm
+@opindex fgnu-tm
+When the option @option{-fgnu-tm} is specified, the compiler
+generates code for the Linux variant of Intel's current Transactional
+Memory ABI specification document (Revision 1.1, May 6 2009).  This is
+an experimental feature whose interface may change in future versions
+of GCC, as the official specification changes.  Please note that not
+all architectures are supported for this feature.
+
+For more information on GCC's support for transactional memory,
+@xref{Enabling libitm,,The GNU Transactional Memory Library,libitm,GNU
+Transactional Memory Library}.
+
+Note that the transactional memory feature is not supported with
+non-call exceptions (@option{-fnon-call-exceptions}).
+
+@item -fms-extensions
+@opindex fms-extensions
+Accept some non-standard constructs used in Microsoft header files.
+
+In C++ code, this allows member names in structures to be similar
+to previous types declarations.
+
+@smallexample
+typedef int UOW;
+struct ABC @{
+  UOW UOW;
+@};
+@end smallexample
+
+Some cases of unnamed fields in structures and unions are only
+accepted with this option.  @xref{Unnamed Fields,,Unnamed struct/union
+fields within structs/unions}, for details.
+
+@item -fplan9-extensions
+Accept some non-standard constructs used in Plan 9 code.
+
+This enables @option{-fms-extensions}, permits passing pointers to
+structures with anonymous fields to functions that expect pointers to
+elements of the type of the field, and permits referring to anonymous
+fields declared using a typedef.  @xref{Unnamed Fields,,Unnamed
+struct/union fields within structs/unions}, for details.  This is only
+supported for C, not C++.
+
+@item -trigraphs
+@opindex trigraphs
+Support ISO C trigraphs.  The @option{-ansi} option (and @option{-std}
+options for strict ISO C conformance) implies @option{-trigraphs}.
+
+@cindex traditional C language
+@cindex C language, traditional
+@item -traditional
+@itemx -traditional-cpp
+@opindex traditional-cpp
+@opindex traditional
+Formerly, these options caused GCC to attempt to emulate a pre-standard
+C compiler.  They are now only supported with the @option{-E} switch.
+The preprocessor continues to support a pre-standard mode.  See the GNU
+CPP manual for details.
+
+@item -fcond-mismatch
+@opindex fcond-mismatch
+Allow conditional expressions with mismatched types in the second and
+third arguments.  The value of such an expression is void.  This option
+is not supported for C++.
+
+@item -flax-vector-conversions
+@opindex flax-vector-conversions
+Allow implicit conversions between vectors with differing numbers of
+elements and/or incompatible element types.  This option should not be
+used for new code.
+
+@item -funsigned-char
+@opindex funsigned-char
+Let the type @code{char} be unsigned, like @code{unsigned char}.
+
+Each kind of machine has a default for what @code{char} should
+be.  It is either like @code{unsigned char} by default or like
+@code{signed char} by default.
+
+Ideally, a portable program should always use @code{signed char} or
+@code{unsigned char} when it depends on the signedness of an object.
+But many programs have been written to use plain @code{char} and
+expect it to be signed, or expect it to be unsigned, depending on the
+machines they were written for.  This option, and its inverse, let you
+make such a program work with the opposite default.
+
+The type @code{char} is always a distinct type from each of
+@code{signed char} or @code{unsigned char}, even though its behavior
+is always just like one of those two.
+
+@item -fsigned-char
+@opindex fsigned-char
+Let the type @code{char} be signed, like @code{signed char}.
+
+Note that this is equivalent to @option{-fno-unsigned-char}, which is
+the negative form of @option{-funsigned-char}.  Likewise, the option
+@option{-fno-signed-char} is equivalent to @option{-funsigned-char}.
+
+@item -fsigned-bitfields
+@itemx -funsigned-bitfields
+@itemx -fno-signed-bitfields
+@itemx -fno-unsigned-bitfields
+@opindex fsigned-bitfields
+@opindex funsigned-bitfields
+@opindex fno-signed-bitfields
+@opindex fno-unsigned-bitfields
+These options control whether a bit-field is signed or unsigned, when the
+declaration does not use either @code{signed} or @code{unsigned}.  By
+default, such a bit-field is signed, because this is consistent: the
+basic integer types such as @code{int} are signed types.
+@end table
+
+@node C++ Dialect Options
+@section Options Controlling C++ Dialect
+
+@cindex compiler options, C++
+@cindex C++ options, command-line
+@cindex options, C++
+This section describes the command-line options that are only meaningful
+for C++ programs.  You can also use most of the GNU compiler options
+regardless of what language your program is in.  For example, you
+might compile a file @code{firstClass.C} like this:
+
+@smallexample
+g++ -g -frepo -O -c firstClass.C
+@end smallexample
+
+@noindent
+In this example, only @option{-frepo} is an option meant
+only for C++ programs; you can use the other options with any
+language supported by GCC@.
+
+Here is a list of options that are @emph{only} for compiling C++ programs:
+
+@table @gcctabopt
+
+@item -fabi-version=@var{n}
+@opindex fabi-version
+Use version @var{n} of the C++ ABI@.  The default is version 2.
+
+Version 0 refers to the version conforming most closely to
+the C++ ABI specification.  Therefore, the ABI obtained using version 0
+will change in different versions of G++ as ABI bugs are fixed.
+
+Version 1 is the version of the C++ ABI that first appeared in G++ 3.2.  
+
+Version 2 is the version of the C++ ABI that first appeared in G++ 3.4.  
+
+Version 3 corrects an error in mangling a constant address as a
+template argument.
+
+Version 4, which first appeared in G++ 4.5, implements a standard
+mangling for vector types.
+
+Version 5, which first appeared in G++ 4.6, corrects the mangling of
+attribute const/volatile on function pointer types, decltype of a
+plain decl, and use of a function parameter in the declaration of
+another parameter.
+
+Version 6, which first appeared in G++ 4.7, corrects the promotion
+behavior of C++11 scoped enums and the mangling of template argument
+packs, const/static_cast, prefix ++ and --, and a class scope function
+used as a template argument.
+
+See also @option{-Wabi}.
+
+@item -fno-access-control
+@opindex fno-access-control
+Turn off all access checking.  This switch is mainly useful for working
+around bugs in the access control code.
+
+@item -fcheck-new
+@opindex fcheck-new
+Check that the pointer returned by @code{operator new} is non-null
+before attempting to modify the storage allocated.  This check is
+normally unnecessary because the C++ standard specifies that
+@code{operator new} only returns @code{0} if it is declared
+@samp{throw()}, in which case the compiler always checks the
+return value even without this option.  In all other cases, when
+@code{operator new} has a non-empty exception specification, memory
+exhaustion is signalled by throwing @code{std::bad_alloc}.  See also
+@samp{new (nothrow)}.
+
+@item -fconstexpr-depth=@var{n}
+@opindex fconstexpr-depth
+Set the maximum nested evaluation depth for C++11 constexpr functions
+to @var{n}.  A limit is needed to detect endless recursion during
+constant expression evaluation.  The minimum specified by the standard
+is 512.
+
+@item -fdeduce-init-list
+@opindex fdeduce-init-list
+Enable deduction of a template type parameter as
+@code{std::initializer_list} from a brace-enclosed initializer list, i.e.@:
+
+@smallexample
+template <class T> auto forward(T t) -> decltype (realfn (t))
+@{
+  return realfn (t);
+@}
+
+void f()
+@{
+  forward(@{1,2@}); // call forward<std::initializer_list<int>>
+@}
+@end smallexample
+
+This deduction was implemented as a possible extension to the
+originally proposed semantics for the C++11 standard, but was not part
+of the final standard, so it is disabled by default.  This option is
+deprecated, and may be removed in a future version of G++.
+
+@item -ffriend-injection
+@opindex ffriend-injection
+Inject friend functions into the enclosing namespace, so that they are
+visible outside the scope of the class in which they are declared.
+Friend functions were documented to work this way in the old Annotated
+C++ Reference Manual, and versions of G++ before 4.1 always worked
+that way.  However, in ISO C++ a friend function that is not declared
+in an enclosing scope can only be found using argument dependent
+lookup.  This option causes friends to be injected as they were in
+earlier releases.
+
+This option is for compatibility, and may be removed in a future
+release of G++.
+
+@item -fno-elide-constructors
+@opindex fno-elide-constructors
+The C++ standard allows an implementation to omit creating a temporary
+that is only used to initialize another object of the same type.
+Specifying this option disables that optimization, and forces G++ to
+call the copy constructor in all cases.
+
+@item -fno-enforce-eh-specs
+@opindex fno-enforce-eh-specs
+Don't generate code to check for violation of exception specifications
+at run time.  This option violates the C++ standard, but may be useful
+for reducing code size in production builds, much like defining
+@samp{NDEBUG}.  This does not give user code permission to throw
+exceptions in violation of the exception specifications; the compiler
+still optimizes based on the specifications, so throwing an
+unexpected exception results in undefined behavior at run time.
+
+@item -fextern-tls-init
+@itemx -fno-extern-tls-init
+@opindex fextern-tls-init
+@opindex fno-extern-tls-init
+The C++11 and OpenMP standards allow @samp{thread_local} and
+@samp{threadprivate} variables to have dynamic (runtime)
+initialization.  To support this, any use of such a variable goes
+through a wrapper function that performs any necessary initialization.
+When the use and definition of the variable are in the same
+translation unit, this overhead can be optimized away, but when the
+use is in a different translation unit there is significant overhead
+even if the variable doesn't actually need dynamic initialization.  If
+the programmer can be sure that no use of the variable in a
+non-defining TU needs to trigger dynamic initialization (either
+because the variable is statically initialized, or a use of the
+variable in the defining TU will be executed before any uses in
+another TU), they can avoid this overhead with the
+@option{-fno-extern-tls-init} option.
+
+On targets that support symbol aliases, the default is
+@option{-fextern-tls-init}.  On targets that do not support symbol
+aliases, the default is @option{-fno-extern-tls-init}.
+
+@item -ffor-scope
+@itemx -fno-for-scope
+@opindex ffor-scope
+@opindex fno-for-scope
+If @option{-ffor-scope} is specified, the scope of variables declared in
+a @i{for-init-statement} is limited to the @samp{for} loop itself,
+as specified by the C++ standard.
+If @option{-fno-for-scope} is specified, the scope of variables declared in
+a @i{for-init-statement} extends to the end of the enclosing scope,
+as was the case in old versions of G++, and other (traditional)
+implementations of C++.
+
+If neither flag is given, the default is to follow the standard,
+but to allow and give a warning for old-style code that would
+otherwise be invalid, or have different behavior.
+
+@item -fno-gnu-keywords
+@opindex fno-gnu-keywords
+Do not recognize @code{typeof} as a keyword, so that code can use this
+word as an identifier.  You can use the keyword @code{__typeof__} instead.
+@option{-ansi} implies @option{-fno-gnu-keywords}.
+
+@item -fno-implicit-templates
+@opindex fno-implicit-templates
+Never emit code for non-inline templates that are instantiated
+implicitly (i.e.@: by use); only emit code for explicit instantiations.
+@xref{Template Instantiation}, for more information.
+
+@item -fno-implicit-inline-templates
+@opindex fno-implicit-inline-templates
+Don't emit code for implicit instantiations of inline templates, either.
+The default is to handle inlines differently so that compiles with and
+without optimization need the same set of explicit instantiations.
+
+@item -fno-implement-inlines
+@opindex fno-implement-inlines
+To save space, do not emit out-of-line copies of inline functions
+controlled by @samp{#pragma implementation}.  This causes linker
+errors if these functions are not inlined everywhere they are called.
+
+@item -fms-extensions
+@opindex fms-extensions
+Disable Wpedantic warnings about constructs used in MFC, such as implicit
+int and getting a pointer to member function via non-standard syntax.
+
+@item -fno-nonansi-builtins
+@opindex fno-nonansi-builtins
+Disable built-in declarations of functions that are not mandated by
+ANSI/ISO C@.  These include @code{ffs}, @code{alloca}, @code{_exit},
+@code{index}, @code{bzero}, @code{conjf}, and other related functions.
+
+@item -fnothrow-opt
+@opindex fnothrow-opt
+Treat a @code{throw()} exception specification as if it were a
+@code{noexcept} specification to reduce or eliminate the text size
+overhead relative to a function with no exception specification.  If
+the function has local variables of types with non-trivial
+destructors, the exception specification actually makes the
+function smaller because the EH cleanups for those variables can be
+optimized away.  The semantic effect is that an exception thrown out of
+a function with such an exception specification results in a call
+to @code{terminate} rather than @code{unexpected}.
+
+@item -fno-operator-names
+@opindex fno-operator-names
+Do not treat the operator name keywords @code{and}, @code{bitand},
+@code{bitor}, @code{compl}, @code{not}, @code{or} and @code{xor} as
+synonyms as keywords.
+
+@item -fno-optional-diags
+@opindex fno-optional-diags
+Disable diagnostics that the standard says a compiler does not need to
+issue.  Currently, the only such diagnostic issued by G++ is the one for
+a name having multiple meanings within a class.
+
+@item -fpermissive
+@opindex fpermissive
+Downgrade some diagnostics about nonconformant code from errors to
+warnings.  Thus, using @option{-fpermissive} allows some
+nonconforming code to compile.
+
+@item -fno-pretty-templates
+@opindex fno-pretty-templates
+When an error message refers to a specialization of a function
+template, the compiler normally prints the signature of the
+template followed by the template arguments and any typedefs or
+typenames in the signature (e.g. @code{void f(T) [with T = int]}
+rather than @code{void f(int)}) so that it's clear which template is
+involved.  When an error message refers to a specialization of a class
+template, the compiler omits any template arguments that match
+the default template arguments for that template.  If either of these
+behaviors make it harder to understand the error message rather than
+easier, you can use @option{-fno-pretty-templates} to disable them.
+
+@item -frepo
+@opindex frepo
+Enable automatic template instantiation at link time.  This option also
+implies @option{-fno-implicit-templates}.  @xref{Template
+Instantiation}, for more information.
+
+@item -fno-rtti
+@opindex fno-rtti
+Disable generation of information about every class with virtual
+functions for use by the C++ run-time type identification features
+(@samp{dynamic_cast} and @samp{typeid}).  If you don't use those parts
+of the language, you can save some space by using this flag.  Note that
+exception handling uses the same information, but G++ generates it as
+needed. The @samp{dynamic_cast} operator can still be used for casts that
+do not require run-time type information, i.e.@: casts to @code{void *} or to
+unambiguous base classes.
+
+@item -fstats
+@opindex fstats
+Emit statistics about front-end processing at the end of the compilation.
+This information is generally only useful to the G++ development team.
+
+@item -fstrict-enums
+@opindex fstrict-enums
+Allow the compiler to optimize using the assumption that a value of
+enumerated type can only be one of the values of the enumeration (as
+defined in the C++ standard; basically, a value that can be
+represented in the minimum number of bits needed to represent all the
+enumerators).  This assumption may not be valid if the program uses a
+cast to convert an arbitrary integer value to the enumerated type.
+
+@item -ftemplate-backtrace-limit=@var{n}
+@opindex ftemplate-backtrace-limit
+Set the maximum number of template instantiation notes for a single
+warning or error to @var{n}.  The default value is 10.
+
+@item -ftemplate-depth=@var{n}
+@opindex ftemplate-depth
+Set the maximum instantiation depth for template classes to @var{n}.
+A limit on the template instantiation depth is needed to detect
+endless recursions during template class instantiation.  ANSI/ISO C++
+conforming programs must not rely on a maximum depth greater than 17
+(changed to 1024 in C++11).  The default value is 900, as the compiler
+can run out of stack space before hitting 1024 in some situations.
+
+@item -fno-threadsafe-statics
+@opindex fno-threadsafe-statics
+Do not emit the extra code to use the routines specified in the C++
+ABI for thread-safe initialization of local statics.  You can use this
+option to reduce code size slightly in code that doesn't need to be
+thread-safe.
+
+@item -fuse-cxa-atexit
+@opindex fuse-cxa-atexit
+Register destructors for objects with static storage duration with the
+@code{__cxa_atexit} function rather than the @code{atexit} function.
+This option is required for fully standards-compliant handling of static
+destructors, but only works if your C library supports
+@code{__cxa_atexit}.
+
+@item -fno-use-cxa-get-exception-ptr
+@opindex fno-use-cxa-get-exception-ptr
+Don't use the @code{__cxa_get_exception_ptr} runtime routine.  This
+causes @code{std::uncaught_exception} to be incorrect, but is necessary
+if the runtime routine is not available.
+
+@item -fvisibility-inlines-hidden
+@opindex fvisibility-inlines-hidden
+This switch declares that the user does not attempt to compare
+pointers to inline functions or methods where the addresses of the two functions
+are taken in different shared objects.
+
+The effect of this is that GCC may, effectively, mark inline methods with
+@code{__attribute__ ((visibility ("hidden")))} so that they do not
+appear in the export table of a DSO and do not require a PLT indirection
+when used within the DSO@.  Enabling this option can have a dramatic effect
+on load and link times of a DSO as it massively reduces the size of the
+dynamic export table when the library makes heavy use of templates.
+
+The behavior of this switch is not quite the same as marking the
+methods as hidden directly, because it does not affect static variables
+local to the function or cause the compiler to deduce that
+the function is defined in only one shared object.
+
+You may mark a method as having a visibility explicitly to negate the
+effect of the switch for that method.  For example, if you do want to
+compare pointers to a particular inline method, you might mark it as
+having default visibility.  Marking the enclosing class with explicit
+visibility has no effect.
+
+Explicitly instantiated inline methods are unaffected by this option
+as their linkage might otherwise cross a shared library boundary.
+@xref{Template Instantiation}.
+
+@item -fvisibility-ms-compat
+@opindex fvisibility-ms-compat
+This flag attempts to use visibility settings to make GCC's C++
+linkage model compatible with that of Microsoft Visual Studio.
+
+The flag makes these changes to GCC's linkage model:
+
+@enumerate
+@item
+It sets the default visibility to @code{hidden}, like
+@option{-fvisibility=hidden}.
+
+@item
+Types, but not their members, are not hidden by default.
+
+@item
+The One Definition Rule is relaxed for types without explicit
+visibility specifications that are defined in more than one
+shared object: those declarations are permitted if they are
+permitted when this option is not used.
+@end enumerate
+
+In new code it is better to use @option{-fvisibility=hidden} and
+export those classes that are intended to be externally visible.
+Unfortunately it is possible for code to rely, perhaps accidentally,
+on the Visual Studio behavior.
+
+Among the consequences of these changes are that static data members
+of the same type with the same name but defined in different shared
+objects are different, so changing one does not change the other;
+and that pointers to function members defined in different shared
+objects may not compare equal.  When this flag is given, it is a
+violation of the ODR to define types with the same name differently.
+
+@item -fno-weak
+@opindex fno-weak
+Do not use weak symbol support, even if it is provided by the linker.
+By default, G++ uses weak symbols if they are available.  This
+option exists only for testing, and should not be used by end-users;
+it results in inferior code and has no benefits.  This option may
+be removed in a future release of G++.
+
+@item -nostdinc++
+@opindex nostdinc++
+Do not search for header files in the standard directories specific to
+C++, but do still search the other standard directories.  (This option
+is used when building the C++ library.)
+@end table
+
+In addition, these optimization, warning, and code generation options
+have meanings only for C++ programs:
+
+@table @gcctabopt
+@item -fno-default-inline
+@opindex fno-default-inline
+Do not assume @samp{inline} for functions defined inside a class scope.
+@xref{Optimize Options,,Options That Control Optimization}.  Note that these
+functions have linkage like inline functions; they just aren't
+inlined by default.
+
+@item -Wabi @r{(C, Objective-C, C++ and Objective-C++ only)}
+@opindex Wabi
+@opindex Wno-abi
+Warn when G++ generates code that is probably not compatible with the
+vendor-neutral C++ ABI@.  Although an effort has been made to warn about
+all such cases, there are probably some cases that are not warned about,
+even though G++ is generating incompatible code.  There may also be
+cases where warnings are emitted even though the code that is generated
+is compatible.
+
+You should rewrite your code to avoid these warnings if you are
+concerned about the fact that code generated by G++ may not be binary
+compatible with code generated by other compilers.
+
+The known incompatibilities in @option{-fabi-version=2} (the default) include:
+
+@itemize @bullet
+
+@item
+A template with a non-type template parameter of reference type is
+mangled incorrectly:
+@smallexample
+extern int N;
+template <int &> struct S @{@};
+void n (S<N>) @{2@}
+@end smallexample
+
+This is fixed in @option{-fabi-version=3}.
+
+@item
+SIMD vector types declared using @code{__attribute ((vector_size))} are
+mangled in a non-standard way that does not allow for overloading of
+functions taking vectors of different sizes.
+
+The mangling is changed in @option{-fabi-version=4}.
+@end itemize
+
+The known incompatibilities in @option{-fabi-version=1} include:
+
+@itemize @bullet
+
+@item
+Incorrect handling of tail-padding for bit-fields.  G++ may attempt to
+pack data into the same byte as a base class.  For example:
+
+@smallexample
+struct A @{ virtual void f(); int f1 : 1; @};
+struct B : public A @{ int f2 : 1; @};
+@end smallexample
+
+@noindent
+In this case, G++ places @code{B::f2} into the same byte
+as @code{A::f1}; other compilers do not.  You can avoid this problem
+by explicitly padding @code{A} so that its size is a multiple of the
+byte size on your platform; that causes G++ and other compilers to
+lay out @code{B} identically.
+
+@item
+Incorrect handling of tail-padding for virtual bases.  G++ does not use
+tail padding when laying out virtual bases.  For example:
+
+@smallexample
+struct A @{ virtual void f(); char c1; @};
+struct B @{ B(); char c2; @};
+struct C : public A, public virtual B @{@};
+@end smallexample
+
+@noindent
+In this case, G++ does not place @code{B} into the tail-padding for
+@code{A}; other compilers do.  You can avoid this problem by
+explicitly padding @code{A} so that its size is a multiple of its
+alignment (ignoring virtual base classes); that causes G++ and other
+compilers to lay out @code{C} identically.
+
+@item
+Incorrect handling of bit-fields with declared widths greater than that
+of their underlying types, when the bit-fields appear in a union.  For
+example:
+
+@smallexample
+union U @{ int i : 4096; @};
+@end smallexample
+
+@noindent
+Assuming that an @code{int} does not have 4096 bits, G++ makes the
+union too small by the number of bits in an @code{int}.
+
+@item
+Empty classes can be placed at incorrect offsets.  For example:
+
+@smallexample
+struct A @{@};
+
+struct B @{
+  A a;
+  virtual void f ();
+@};
+
+struct C : public B, public A @{@};
+@end smallexample
+
+@noindent
+G++ places the @code{A} base class of @code{C} at a nonzero offset;
+it should be placed at offset zero.  G++ mistakenly believes that the
+@code{A} data member of @code{B} is already at offset zero.
+
+@item
+Names of template functions whose types involve @code{typename} or
+template template parameters can be mangled incorrectly.
+
+@smallexample
+template <typename Q>
+void f(typename Q::X) @{@}
+
+template <template <typename> class Q>
+void f(typename Q<int>::X) @{@}
+@end smallexample
+
+@noindent
+Instantiations of these templates may be mangled incorrectly.
+
+@end itemize
+
+It also warns about psABI-related changes.  The known psABI changes at this
+point include:
+
+@itemize @bullet
+
+@item
+For SysV/x86-64, unions with @code{long double} members are 
+passed in memory as specified in psABI.  For example:
+
+@smallexample
+union U @{
+  long double ld;
+  int i;
+@};
+@end smallexample
+
+@noindent
+@code{union U} is always passed in memory.
+
+@end itemize
+
+@item -Wctor-dtor-privacy @r{(C++ and Objective-C++ only)}
+@opindex Wctor-dtor-privacy
+@opindex Wno-ctor-dtor-privacy
+Warn when a class seems unusable because all the constructors or
+destructors in that class are private, and it has neither friends nor
+public static member functions.  Also warn if there are no non-private
+methods, and there's at least one private member function that isn't
+a constructor or destructor.
+
+@item -Wdelete-non-virtual-dtor @r{(C++ and Objective-C++ only)}
+@opindex Wdelete-non-virtual-dtor
+@opindex Wno-delete-non-virtual-dtor
+Warn when @samp{delete} is used to destroy an instance of a class that
+has virtual functions and non-virtual destructor. It is unsafe to delete
+an instance of a derived class through a pointer to a base class if the
+base class does not have a virtual destructor.  This warning is enabled
+by @option{-Wall}.
+
+@item -Wliteral-suffix @r{(C++ and Objective-C++ only)}
+@opindex Wliteral-suffix
+@opindex Wno-literal-suffix
+Warn when a string or character literal is followed by a ud-suffix which does
+not begin with an underscore.  As a conforming extension, GCC treats such
+suffixes as separate preprocessing tokens in order to maintain backwards
+compatibility with code that uses formatting macros from @code{<inttypes.h>}.
+For example:
+
+@smallexample
+#define __STDC_FORMAT_MACROS
+#include <inttypes.h>
+#include <stdio.h>
+
+int main() @{
+  int64_t i64 = 123;
+  printf("My int64: %"PRId64"\n", i64);
+@}
+@end smallexample
+
+In this case, @code{PRId64} is treated as a separate preprocessing token.
+
+This warning is enabled by default.
+
+@item -Wnarrowing @r{(C++ and Objective-C++ only)}
+@opindex Wnarrowing
+@opindex Wno-narrowing
+Warn when a narrowing conversion prohibited by C++11 occurs within
+@samp{@{ @}}, e.g.
+
+@smallexample
+int i = @{ 2.2 @}; // error: narrowing from double to int
+@end smallexample
+
+This flag is included in @option{-Wall} and @option{-Wc++11-compat}.
+
+With @option{-std=c++11}, @option{-Wno-narrowing} suppresses the diagnostic
+required by the standard.  Note that this does not affect the meaning
+of well-formed code; narrowing conversions are still considered
+ill-formed in SFINAE context.
+
+@item -Wnoexcept @r{(C++ and Objective-C++ only)}
+@opindex Wnoexcept
+@opindex Wno-noexcept
+Warn when a noexcept-expression evaluates to false because of a call
+to a function that does not have a non-throwing exception
+specification (i.e. @samp{throw()} or @samp{noexcept}) but is known by
+the compiler to never throw an exception.
+
+@item -Wnon-virtual-dtor @r{(C++ and Objective-C++ only)}
+@opindex Wnon-virtual-dtor
+@opindex Wno-non-virtual-dtor
+Warn when a class has virtual functions and an accessible non-virtual
+destructor, in which case it is possible but unsafe to delete
+an instance of a derived class through a pointer to the base class.
+This warning is also enabled if @option{-Weffc++} is specified.
+
+@item -Wreorder @r{(C++ and Objective-C++ only)}
+@opindex Wreorder
+@opindex Wno-reorder
+@cindex reordering, warning
+@cindex warning for reordering of member initializers
+Warn when the order of member initializers given in the code does not
+match the order in which they must be executed.  For instance:
+
+@smallexample
+struct A @{
+  int i;
+  int j;
+  A(): j (0), i (1) @{ @}
+@};
+@end smallexample
+
+@noindent
+The compiler rearranges the member initializers for @samp{i}
+and @samp{j} to match the declaration order of the members, emitting
+a warning to that effect.  This warning is enabled by @option{-Wall}.
+
+@item -fext-numeric-literals @r{(C++ and Objective-C++ only)}
+@opindex fext-numeric-literals
+@opindex fno-ext-numeric-literals
+Accept imaginary, fixed-point, or machine-defined
+literal number suffixes as GNU extensions.
+When this option is turned off these suffixes are treated
+as C++11 user-defined literal numeric suffixes.
+This is on by default for all pre-C++11 dialects and all GNU dialects:
+@option{-std=c++98}, @option{-std=gnu++98}, @option{-std=gnu++11},
+@option{-std=gnu++1y}.
+This option is off by default
+for ISO C++11 onwards (@option{-std=c++11}, ...).
+@end table
+
+The following @option{-W@dots{}} options are not affected by @option{-Wall}.
+
+@table @gcctabopt
+@item -Weffc++ @r{(C++ and Objective-C++ only)}
+@opindex Weffc++
+@opindex Wno-effc++
+Warn about violations of the following style guidelines from Scott Meyers'
+@cite{Effective C++, Second Edition} book:
+
+@itemize @bullet
+@item
+Item 11:  Define a copy constructor and an assignment operator for classes
+with dynamically-allocated memory.
+
+@item
+Item 12:  Prefer initialization to assignment in constructors.
+
+@item
+Item 14:  Make destructors virtual in base classes.
+
+@item
+Item 15:  Have @code{operator=} return a reference to @code{*this}.
+
+@item
+Item 23:  Don't try to return a reference when you must return an object.
+
+@end itemize
+
+Also warn about violations of the following style guidelines from
+Scott Meyers' @cite{More Effective C++} book:
+
+@itemize @bullet
+@item
+Item 6:  Distinguish between prefix and postfix forms of increment and
+decrement operators.
+
+@item
+Item 7:  Never overload @code{&&}, @code{||}, or @code{,}.
+
+@end itemize
+
+When selecting this option, be aware that the standard library
+headers do not obey all of these guidelines; use @samp{grep -v}
+to filter out those warnings.
+
+@item -Wstrict-null-sentinel @r{(C++ and Objective-C++ only)}
+@opindex Wstrict-null-sentinel
+@opindex Wno-strict-null-sentinel
+Warn about the use of an uncasted @code{NULL} as sentinel.  When
+compiling only with GCC this is a valid sentinel, as @code{NULL} is defined
+to @code{__null}.  Although it is a null pointer constant rather than a
+null pointer, it is guaranteed to be of the same size as a pointer.
+But this use is not portable across different compilers.
+
+@item -Wno-non-template-friend @r{(C++ and Objective-C++ only)}
+@opindex Wno-non-template-friend
+@opindex Wnon-template-friend
+Disable warnings when non-templatized friend functions are declared
+within a template.  Since the advent of explicit template specification
+support in G++, if the name of the friend is an unqualified-id (i.e.,
+@samp{friend foo(int)}), the C++ language specification demands that the
+friend declare or define an ordinary, nontemplate function.  (Section
+14.5.3).  Before G++ implemented explicit specification, unqualified-ids
+could be interpreted as a particular specialization of a templatized
+function.  Because this non-conforming behavior is no longer the default
+behavior for G++, @option{-Wnon-template-friend} allows the compiler to
+check existing code for potential trouble spots and is on by default.
+This new compiler behavior can be turned off with
+@option{-Wno-non-template-friend}, which keeps the conformant compiler code
+but disables the helpful warning.
+
+@item -Wold-style-cast @r{(C++ and Objective-C++ only)}
+@opindex Wold-style-cast
+@opindex Wno-old-style-cast
+Warn if an old-style (C-style) cast to a non-void type is used within
+a C++ program.  The new-style casts (@samp{dynamic_cast},
+@samp{static_cast}, @samp{reinterpret_cast}, and @samp{const_cast}) are
+less vulnerable to unintended effects and much easier to search for.
+
+@item -Woverloaded-virtual @r{(C++ and Objective-C++ only)}
+@opindex Woverloaded-virtual
+@opindex Wno-overloaded-virtual
+@cindex overloaded virtual function, warning
+@cindex warning for overloaded virtual function
+Warn when a function declaration hides virtual functions from a
+base class.  For example, in:
+
+@smallexample
+struct A @{
+  virtual void f();
+@};
+
+struct B: public A @{
+  void f(int);
+@};
+@end smallexample
+
+the @code{A} class version of @code{f} is hidden in @code{B}, and code
+like:
+
+@smallexample
+B* b;
+b->f();
+@end smallexample
+
+@noindent
+fails to compile.
+
+@item -Wno-pmf-conversions @r{(C++ and Objective-C++ only)}
+@opindex Wno-pmf-conversions
+@opindex Wpmf-conversions
+Disable the diagnostic for converting a bound pointer to member function
+to a plain pointer.
+
+@item -Wsign-promo @r{(C++ and Objective-C++ only)}
+@opindex Wsign-promo
+@opindex Wno-sign-promo
+Warn when overload resolution chooses a promotion from unsigned or
+enumerated type to a signed type, over a conversion to an unsigned type of
+the same size.  Previous versions of G++ tried to preserve
+unsignedness, but the standard mandates the current behavior.
+@end table
+
+@node Objective-C and Objective-C++ Dialect Options
+@section Options Controlling Objective-C and Objective-C++ Dialects
+
+@cindex compiler options, Objective-C and Objective-C++
+@cindex Objective-C and Objective-C++ options, command-line
+@cindex options, Objective-C and Objective-C++
+(NOTE: This manual does not describe the Objective-C and Objective-C++
+languages themselves.  @xref{Standards,,Language Standards
+Supported by GCC}, for references.)
+
+This section describes the command-line options that are only meaningful
+for Objective-C and Objective-C++ programs.  You can also use most of
+the language-independent GNU compiler options.
+For example, you might compile a file @code{some_class.m} like this:
+
+@smallexample
+gcc -g -fgnu-runtime -O -c some_class.m
+@end smallexample
+
+@noindent
+In this example, @option{-fgnu-runtime} is an option meant only for
+Objective-C and Objective-C++ programs; you can use the other options with
+any language supported by GCC@.
+
+Note that since Objective-C is an extension of the C language, Objective-C
+compilations may also use options specific to the C front-end (e.g.,
+@option{-Wtraditional}).  Similarly, Objective-C++ compilations may use
+C++-specific options (e.g., @option{-Wabi}).
+
+Here is a list of options that are @emph{only} for compiling Objective-C
+and Objective-C++ programs:
+
+@table @gcctabopt
+@item -fconstant-string-class=@var{class-name}
+@opindex fconstant-string-class
+Use @var{class-name} as the name of the class to instantiate for each
+literal string specified with the syntax @code{@@"@dots{}"}.  The default
+class name is @code{NXConstantString} if the GNU runtime is being used, and
+@code{NSConstantString} if the NeXT runtime is being used (see below).  The
+@option{-fconstant-cfstrings} option, if also present, overrides the
+@option{-fconstant-string-class} setting and cause @code{@@"@dots{}"} literals
+to be laid out as constant CoreFoundation strings.
+
+@item -fgnu-runtime
+@opindex fgnu-runtime
+Generate object code compatible with the standard GNU Objective-C
+runtime.  This is the default for most types of systems.
+
+@item -fnext-runtime
+@opindex fnext-runtime
+Generate output compatible with the NeXT runtime.  This is the default
+for NeXT-based systems, including Darwin and Mac OS X@.  The macro
+@code{__NEXT_RUNTIME__} is predefined if (and only if) this option is
+used.
+
+@item -fno-nil-receivers
+@opindex fno-nil-receivers
+Assume that all Objective-C message dispatches (@code{[receiver
+message:arg]}) in this translation unit ensure that the receiver is
+not @code{nil}.  This allows for more efficient entry points in the
+runtime to be used.  This option is only available in conjunction with
+the NeXT runtime and ABI version 0 or 1.
+
+@item -fobjc-abi-version=@var{n}
+@opindex fobjc-abi-version
+Use version @var{n} of the Objective-C ABI for the selected runtime.
+This option is currently supported only for the NeXT runtime.  In that
+case, Version 0 is the traditional (32-bit) ABI without support for
+properties and other Objective-C 2.0 additions.  Version 1 is the
+traditional (32-bit) ABI with support for properties and other
+Objective-C 2.0 additions.  Version 2 is the modern (64-bit) ABI.  If
+nothing is specified, the default is Version 0 on 32-bit target
+machines, and Version 2 on 64-bit target machines.
+
+@item -fobjc-call-cxx-cdtors
+@opindex fobjc-call-cxx-cdtors
+For each Objective-C class, check if any of its instance variables is a
+C++ object with a non-trivial default constructor.  If so, synthesize a
+special @code{- (id) .cxx_construct} instance method which runs
+non-trivial default constructors on any such instance variables, in order,
+and then return @code{self}.  Similarly, check if any instance variable
+is a C++ object with a non-trivial destructor, and if so, synthesize a
+special @code{- (void) .cxx_destruct} method which runs
+all such default destructors, in reverse order.
+
+The @code{- (id) .cxx_construct} and @code{- (void) .cxx_destruct}
+methods thusly generated only operate on instance variables
+declared in the current Objective-C class, and not those inherited
+from superclasses.  It is the responsibility of the Objective-C
+runtime to invoke all such methods in an object's inheritance
+hierarchy.  The @code{- (id) .cxx_construct} methods are invoked
+by the runtime immediately after a new object instance is allocated;
+the @code{- (void) .cxx_destruct} methods are invoked immediately
+before the runtime deallocates an object instance.
+
+As of this writing, only the NeXT runtime on Mac OS X 10.4 and later has
+support for invoking the @code{- (id) .cxx_construct} and
+@code{- (void) .cxx_destruct} methods.
+
+@item -fobjc-direct-dispatch
+@opindex fobjc-direct-dispatch
+Allow fast jumps to the message dispatcher.  On Darwin this is
+accomplished via the comm page.
+
+@item -fobjc-exceptions
+@opindex fobjc-exceptions
+Enable syntactic support for structured exception handling in
+Objective-C, similar to what is offered by C++ and Java.  This option
+is required to use the Objective-C keywords @code{@@try},
+@code{@@throw}, @code{@@catch}, @code{@@finally} and
+@code{@@synchronized}.  This option is available with both the GNU
+runtime and the NeXT runtime (but not available in conjunction with
+the NeXT runtime on Mac OS X 10.2 and earlier).
+
+@item -fobjc-gc
+@opindex fobjc-gc
+Enable garbage collection (GC) in Objective-C and Objective-C++
+programs.  This option is only available with the NeXT runtime; the
+GNU runtime has a different garbage collection implementation that
+does not require special compiler flags.
+
+@item -fobjc-nilcheck
+@opindex fobjc-nilcheck
+For the NeXT runtime with version 2 of the ABI, check for a nil
+receiver in method invocations before doing the actual method call.
+This is the default and can be disabled using
+@option{-fno-objc-nilcheck}.  Class methods and super calls are never
+checked for nil in this way no matter what this flag is set to.
+Currently this flag does nothing when the GNU runtime, or an older
+version of the NeXT runtime ABI, is used.
+
+@item -fobjc-std=objc1
+@opindex fobjc-std
+Conform to the language syntax of Objective-C 1.0, the language
+recognized by GCC 4.0.  This only affects the Objective-C additions to
+the C/C++ language; it does not affect conformance to C/C++ standards,
+which is controlled by the separate C/C++ dialect option flags.  When
+this option is used with the Objective-C or Objective-C++ compiler,
+any Objective-C syntax that is not recognized by GCC 4.0 is rejected.
+This is useful if you need to make sure that your Objective-C code can
+be compiled with older versions of GCC@.
+
+@item -freplace-objc-classes
+@opindex freplace-objc-classes
+Emit a special marker instructing @command{ld(1)} not to statically link in
+the resulting object file, and allow @command{dyld(1)} to load it in at
+run time instead.  This is used in conjunction with the Fix-and-Continue
+debugging mode, where the object file in question may be recompiled and
+dynamically reloaded in the course of program execution, without the need
+to restart the program itself.  Currently, Fix-and-Continue functionality
+is only available in conjunction with the NeXT runtime on Mac OS X 10.3
+and later.
+
+@item -fzero-link
+@opindex fzero-link
+When compiling for the NeXT runtime, the compiler ordinarily replaces calls
+to @code{objc_getClass("@dots{}")} (when the name of the class is known at
+compile time) with static class references that get initialized at load time,
+which improves run-time performance.  Specifying the @option{-fzero-link} flag
+suppresses this behavior and causes calls to @code{objc_getClass("@dots{}")}
+to be retained.  This is useful in Zero-Link debugging mode, since it allows
+for individual class implementations to be modified during program execution.
+The GNU runtime currently always retains calls to @code{objc_get_class("@dots{}")}
+regardless of command-line options.
+
+@item -gen-decls
+@opindex gen-decls
+Dump interface declarations for all classes seen in the source file to a
+file named @file{@var{sourcename}.decl}.
+
+@item -Wassign-intercept @r{(Objective-C and Objective-C++ only)}
+@opindex Wassign-intercept
+@opindex Wno-assign-intercept
+Warn whenever an Objective-C assignment is being intercepted by the
+garbage collector.
+
+@item -Wno-protocol @r{(Objective-C and Objective-C++ only)}
+@opindex Wno-protocol
+@opindex Wprotocol
+If a class is declared to implement a protocol, a warning is issued for
+every method in the protocol that is not implemented by the class.  The
+default behavior is to issue a warning for every method not explicitly
+implemented in the class, even if a method implementation is inherited
+from the superclass.  If you use the @option{-Wno-protocol} option, then
+methods inherited from the superclass are considered to be implemented,
+and no warning is issued for them.
+
+@item -Wselector @r{(Objective-C and Objective-C++ only)}
+@opindex Wselector
+@opindex Wno-selector
+Warn if multiple methods of different types for the same selector are
+found during compilation.  The check is performed on the list of methods
+in the final stage of compilation.  Additionally, a check is performed
+for each selector appearing in a @code{@@selector(@dots{})}
+expression, and a corresponding method for that selector has been found
+during compilation.  Because these checks scan the method table only at
+the end of compilation, these warnings are not produced if the final
+stage of compilation is not reached, for example because an error is
+found during compilation, or because the @option{-fsyntax-only} option is
+being used.
+
+@item -Wstrict-selector-match @r{(Objective-C and Objective-C++ only)}
+@opindex Wstrict-selector-match
+@opindex Wno-strict-selector-match
+Warn if multiple methods with differing argument and/or return types are
+found for a given selector when attempting to send a message using this
+selector to a receiver of type @code{id} or @code{Class}.  When this flag
+is off (which is the default behavior), the compiler omits such warnings
+if any differences found are confined to types that share the same size
+and alignment.
+
+@item -Wundeclared-selector @r{(Objective-C and Objective-C++ only)}
+@opindex Wundeclared-selector
+@opindex Wno-undeclared-selector
+Warn if a @code{@@selector(@dots{})} expression referring to an
+undeclared selector is found.  A selector is considered undeclared if no
+method with that name has been declared before the
+@code{@@selector(@dots{})} expression, either explicitly in an
+@code{@@interface} or @code{@@protocol} declaration, or implicitly in
+an @code{@@implementation} section.  This option always performs its
+checks as soon as a @code{@@selector(@dots{})} expression is found,
+while @option{-Wselector} only performs its checks in the final stage of
+compilation.  This also enforces the coding style convention
+that methods and selectors must be declared before being used.
+
+@item -print-objc-runtime-info
+@opindex print-objc-runtime-info
+Generate C header describing the largest structure that is passed by
+value, if any.
+
+@end table
+
+@node Language Independent Options
+@section Options to Control Diagnostic Messages Formatting
+@cindex options to control diagnostics formatting
+@cindex diagnostic messages
+@cindex message formatting
+
+Traditionally, diagnostic messages have been formatted irrespective of
+the output device's aspect (e.g.@: its width, @dots{}).  You can use the
+options described below
+to control the formatting algorithm for diagnostic messages, 
+e.g.@: how many characters per line, how often source location
+information should be reported.  Note that some language front ends may not
+honor these options.
+
+@table @gcctabopt
+@item -fmessage-length=@var{n}
+@opindex fmessage-length
+Try to format error messages so that they fit on lines of about @var{n}
+characters.  The default is 72 characters for @command{g++} and 0 for the rest of
+the front ends supported by GCC@.  If @var{n} is zero, then no
+line-wrapping is done; each error message appears on a single
+line.
+
+@item -fdiagnostics-show-location=once
+@opindex fdiagnostics-show-location
+Only meaningful in line-wrapping mode.  Instructs the diagnostic messages
+reporter to emit source location information @emph{once}; that is, in
+case the message is too long to fit on a single physical line and has to
+be wrapped, the source location won't be emitted (as prefix) again,
+over and over, in subsequent continuation lines.  This is the default
+behavior.
+
+@item -fdiagnostics-show-location=every-line
+Only meaningful in line-wrapping mode.  Instructs the diagnostic
+messages reporter to emit the same source location information (as
+prefix) for physical lines that result from the process of breaking
+a message which is too long to fit on a single line.
+
+@item -fno-diagnostics-show-option
+@opindex fno-diagnostics-show-option
+@opindex fdiagnostics-show-option
+By default, each diagnostic emitted includes text indicating the
+command-line option that directly controls the diagnostic (if such an
+option is known to the diagnostic machinery).  Specifying the
+@option{-fno-diagnostics-show-option} flag suppresses that behavior.
+
+@item -fno-diagnostics-show-caret
+@opindex fno-diagnostics-show-caret
+@opindex fdiagnostics-show-caret
+By default, each diagnostic emitted includes the original source line
+and a caret '^' indicating the column.  This option suppresses this
+information.
+
+@end table
+
+@node Warning Options
+@section Options to Request or Suppress Warnings
+@cindex options to control warnings
+@cindex warning messages
+@cindex messages, warning
+@cindex suppressing warnings
+
+Warnings are diagnostic messages that report constructions that
+are not inherently erroneous but that are risky or suggest there
+may have been an error.
+
+The following language-independent options do not enable specific
+warnings but control the kinds of diagnostics produced by GCC@.
+
+@table @gcctabopt
+@cindex syntax checking
+@item -fsyntax-only
+@opindex fsyntax-only
+Check the code for syntax errors, but don't do anything beyond that.
+
+@item -fmax-errors=@var{n}
+@opindex fmax-errors
+Limits the maximum number of error messages to @var{n}, at which point
+GCC bails out rather than attempting to continue processing the source
+code.  If @var{n} is 0 (the default), there is no limit on the number
+of error messages produced.  If @option{-Wfatal-errors} is also
+specified, then @option{-Wfatal-errors} takes precedence over this
+option.
+
+@item -w
+@opindex w
+Inhibit all warning messages.
+
+@item -Werror
+@opindex Werror
+@opindex Wno-error
+Make all warnings into errors.
+
+@item -Werror=
+@opindex Werror=
+@opindex Wno-error=
+Make the specified warning into an error.  The specifier for a warning
+is appended; for example @option{-Werror=switch} turns the warnings
+controlled by @option{-Wswitch} into errors.  This switch takes a
+negative form, to be used to negate @option{-Werror} for specific
+warnings; for example @option{-Wno-error=switch} makes
+@option{-Wswitch} warnings not be errors, even when @option{-Werror}
+is in effect.
+
+The warning message for each controllable warning includes the
+option that controls the warning.  That option can then be used with
+@option{-Werror=} and @option{-Wno-error=} as described above.
+(Printing of the option in the warning message can be disabled using the
+@option{-fno-diagnostics-show-option} flag.)
+
+Note that specifying @option{-Werror=}@var{foo} automatically implies
+@option{-W}@var{foo}.  However, @option{-Wno-error=}@var{foo} does not
+imply anything.
+
+@item -Wfatal-errors
+@opindex Wfatal-errors
+@opindex Wno-fatal-errors
+This option causes the compiler to abort compilation on the first error
+occurred rather than trying to keep going and printing further error
+messages.
+
+@end table
+
+You can request many specific warnings with options beginning with
+@samp{-W}, for example @option{-Wimplicit} to request warnings on
+implicit declarations.  Each of these specific warning options also
+has a negative form beginning @samp{-Wno-} to turn off warnings; for
+example, @option{-Wno-implicit}.  This manual lists only one of the
+two forms, whichever is not the default.  For further
+language-specific options also refer to @ref{C++ Dialect Options} and
+@ref{Objective-C and Objective-C++ Dialect Options}.
+
+When an unrecognized warning option is requested (e.g.,
+@option{-Wunknown-warning}), GCC emits a diagnostic stating
+that the option is not recognized.  However, if the @option{-Wno-} form
+is used, the behavior is slightly different: no diagnostic is
+produced for @option{-Wno-unknown-warning} unless other diagnostics
+are being produced.  This allows the use of new @option{-Wno-} options
+with old compilers, but if something goes wrong, the compiler
+warns that an unrecognized option is present.
+
+@table @gcctabopt
+@item -Wpedantic
+@itemx -pedantic
+@opindex pedantic
+@opindex Wpedantic
+Issue all the warnings demanded by strict ISO C and ISO C++;
+reject all programs that use forbidden extensions, and some other
+programs that do not follow ISO C and ISO C++.  For ISO C, follows the
+version of the ISO C standard specified by any @option{-std} option used.
+
+Valid ISO C and ISO C++ programs should compile properly with or without
+this option (though a rare few require @option{-ansi} or a
+@option{-std} option specifying the required version of ISO C)@.  However,
+without this option, certain GNU extensions and traditional C and C++
+features are supported as well.  With this option, they are rejected.
+
+@option{-Wpedantic} does not cause warning messages for use of the
+alternate keywords whose names begin and end with @samp{__}.  Pedantic
+warnings are also disabled in the expression that follows
+@code{__extension__}.  However, only system header files should use
+these escape routes; application programs should avoid them.
+@xref{Alternate Keywords}.
+
+Some users try to use @option{-Wpedantic} to check programs for strict ISO
+C conformance.  They soon find that it does not do quite what they want:
+it finds some non-ISO practices, but not all---only those for which
+ISO C @emph{requires} a diagnostic, and some others for which
+diagnostics have been added.
+
+A feature to report any failure to conform to ISO C might be useful in
+some instances, but would require considerable additional work and would
+be quite different from @option{-Wpedantic}.  We don't have plans to
+support such a feature in the near future.
+
+Where the standard specified with @option{-std} represents a GNU
+extended dialect of C, such as @samp{gnu90} or @samp{gnu99}, there is a
+corresponding @dfn{base standard}, the version of ISO C on which the GNU
+extended dialect is based.  Warnings from @option{-Wpedantic} are given
+where they are required by the base standard.  (It does not make sense
+for such warnings to be given only for features not in the specified GNU
+C dialect, since by definition the GNU dialects of C include all
+features the compiler supports with the given option, and there would be
+nothing to warn about.)
+
+@item -pedantic-errors
+@opindex pedantic-errors
+Like @option{-Wpedantic}, except that errors are produced rather than
+warnings.
+
+@item -Wall
+@opindex Wall
+@opindex Wno-all
+This enables all the warnings about constructions that some users
+consider questionable, and that are easy to avoid (or modify to
+prevent the warning), even in conjunction with macros.  This also
+enables some language-specific warnings described in @ref{C++ Dialect
+Options} and @ref{Objective-C and Objective-C++ Dialect Options}.
+
+@option{-Wall} turns on the following warning flags:
+
+@gccoptlist{-Waddress   @gol
+-Warray-bounds @r{(only with} @option{-O2}@r{)}  @gol
+-Wc++11-compat  @gol
+-Wchar-subscripts  @gol
+-Wenum-compare @r{(in C/ObjC; this is on by default in C++)} @gol
+-Wimplicit-int @r{(C and Objective-C only)} @gol
+-Wimplicit-function-declaration @r{(C and Objective-C only)} @gol
+-Wcomment  @gol
+-Wformat   @gol
+-Wmain @r{(only for C/ObjC and unless} @option{-ffreestanding}@r{)}  @gol
+-Wmaybe-uninitialized @gol
+-Wmissing-braces @r{(only for C/ObjC)} @gol
+-Wnonnull  @gol
+-Wparentheses  @gol
+-Wpointer-sign  @gol
+-Wreorder   @gol
+-Wreturn-type  @gol
+-Wsequence-point  @gol
+-Wsign-compare @r{(only in C++)}  @gol
+-Wstrict-aliasing  @gol
+-Wstrict-overflow=1  @gol
+-Wswitch  @gol
+-Wtrigraphs  @gol
+-Wuninitialized  @gol
+-Wunknown-pragmas  @gol
+-Wunused-function  @gol
+-Wunused-label     @gol
+-Wunused-value     @gol
+-Wunused-variable  @gol
+-Wvolatile-register-var @gol
+}
+
+Note that some warning flags are not implied by @option{-Wall}.  Some of
+them warn about constructions that users generally do not consider
+questionable, but which occasionally you might wish to check for;
+others warn about constructions that are necessary or hard to avoid in
+some cases, and there is no simple way to modify the code to suppress
+the warning. Some of them are enabled by @option{-Wextra} but many of
+them must be enabled individually.
+
+@item -Wextra
+@opindex W
+@opindex Wextra
+@opindex Wno-extra
+This enables some extra warning flags that are not enabled by
+@option{-Wall}. (This option used to be called @option{-W}.  The older
+name is still supported, but the newer name is more descriptive.)
+
+@gccoptlist{-Wclobbered  @gol
+-Wempty-body  @gol
+-Wignored-qualifiers @gol
+-Wmissing-field-initializers  @gol
+-Wmissing-parameter-type @r{(C only)}  @gol
+-Wold-style-declaration @r{(C only)}  @gol
+-Woverride-init  @gol
+-Wsign-compare  @gol
+-Wtype-limits  @gol
+-Wuninitialized  @gol
+-Wunused-parameter @r{(only with} @option{-Wunused} @r{or} @option{-Wall}@r{)} @gol
+-Wunused-but-set-parameter @r{(only with} @option{-Wunused} @r{or} @option{-Wall}@r{)}  @gol
+}
+
+The option @option{-Wextra} also prints warning messages for the
+following cases:
+
+@itemize @bullet
+
+@item
+A pointer is compared against integer zero with @samp{<}, @samp{<=},
+@samp{>}, or @samp{>=}.
+
+@item
+(C++ only) An enumerator and a non-enumerator both appear in a
+conditional expression.
+
+@item
+(C++ only) Ambiguous virtual bases.
+
+@item
+(C++ only) Subscripting an array that has been declared @samp{register}.
+
+@item
+(C++ only) Taking the address of a variable that has been declared
+@samp{register}.
+
+@item
+(C++ only) A base class is not initialized in a derived class's copy
+constructor.
+
+@end itemize
+
+@item -Wchar-subscripts
+@opindex Wchar-subscripts
+@opindex Wno-char-subscripts
+Warn if an array subscript has type @code{char}.  This is a common cause
+of error, as programmers often forget that this type is signed on some
+machines.
+This warning is enabled by @option{-Wall}.
+
+@item -Wcomment
+@opindex Wcomment
+@opindex Wno-comment
+Warn whenever a comment-start sequence @samp{/*} appears in a @samp{/*}
+comment, or whenever a Backslash-Newline appears in a @samp{//} comment.
+This warning is enabled by @option{-Wall}.
+
+@item -Wno-coverage-mismatch
+@opindex Wno-coverage-mismatch
+Warn if feedback profiles do not match when using the
+@option{-fprofile-use} option.
+If a source file is changed between compiling with @option{-fprofile-gen} and
+with @option{-fprofile-use}, the files with the profile feedback can fail
+to match the source file and GCC cannot use the profile feedback
+information.  By default, this warning is enabled and is treated as an
+error.  @option{-Wno-coverage-mismatch} can be used to disable the
+warning or @option{-Wno-error=coverage-mismatch} can be used to
+disable the error.  Disabling the error for this warning can result in
+poorly optimized code and is useful only in the
+case of very minor changes such as bug fixes to an existing code-base.
+Completely disabling the warning is not recommended.
+
+@item -Wno-cpp
+@r{(C, Objective-C, C++, Objective-C++ and Fortran only)}
+
+Suppress warning messages emitted by @code{#warning} directives.
+
+@item -Wdouble-promotion @r{(C, C++, Objective-C and Objective-C++ only)}
+@opindex Wdouble-promotion
+@opindex Wno-double-promotion
+Give a warning when a value of type @code{float} is implicitly
+promoted to @code{double}.  CPUs with a 32-bit ``single-precision''
+floating-point unit implement @code{float} in hardware, but emulate
+@code{double} in software.  On such a machine, doing computations
+using @code{double} values is much more expensive because of the
+overhead required for software emulation.
+
+It is easy to accidentally do computations with @code{double} because
+floating-point literals are implicitly of type @code{double}.  For
+example, in:
+@smallexample
+@group
+float area(float radius)
+@{
+   return 3.14159 * radius * radius;
+@}
+@end group
+@end smallexample
+the compiler performs the entire computation with @code{double}
+because the floating-point literal is a @code{double}.
+
+@item -Wformat
+@itemx -Wformat=@var{n}
+@opindex Wformat
+@opindex Wno-format
+@opindex ffreestanding
+@opindex fno-builtin
+@opindex Wformat=
+Check calls to @code{printf} and @code{scanf}, etc., to make sure that
+the arguments supplied have types appropriate to the format string
+specified, and that the conversions specified in the format string make
+sense.  This includes standard functions, and others specified by format
+attributes (@pxref{Function Attributes}), in the @code{printf},
+@code{scanf}, @code{strftime} and @code{strfmon} (an X/Open extension,
+not in the C standard) families (or other target-specific families).
+Which functions are checked without format attributes having been
+specified depends on the standard version selected, and such checks of
+functions without the attribute specified are disabled by
+@option{-ffreestanding} or @option{-fno-builtin}.
+
+The formats are checked against the format features supported by GNU
+libc version 2.2.  These include all ISO C90 and C99 features, as well
+as features from the Single Unix Specification and some BSD and GNU
+extensions.  Other library implementations may not support all these
+features; GCC does not support warning about features that go beyond a
+particular library's limitations.  However, if @option{-Wpedantic} is used
+with @option{-Wformat}, warnings are given about format features not
+in the selected standard version (but not for @code{strfmon} formats,
+since those are not in any version of the C standard).  @xref{C Dialect
+Options,,Options Controlling C Dialect}.
+
+@table @gcctabopt
+@item -Wformat=1
+@itemx -Wformat
+Option @option{-Wformat} is equivalent to @option{-Wformat=1}, and
+@option{-Wno-format} is equivalent to @option{-Wformat=0}.  Since
+@option{-Wformat} also checks for null format arguments for several
+functions, @option{-Wformat} also implies @option{-Wnonnull}.  Some
+aspects of this level of format checking can be disabled by the
+options: @option{-Wno-format-contains-nul},
+@option{-Wno-format-extra-args}, and @option{-Wno-format-zero-length}.
+@option{-Wformat} is enabled by @option{-Wall}.
+
+@item -Wno-format-contains-nul
+@opindex Wno-format-contains-nul
+@opindex Wformat-contains-nul
+If @option{-Wformat} is specified, do not warn about format strings that
+contain NUL bytes.
+
+@item -Wno-format-extra-args
+@opindex Wno-format-extra-args
+@opindex Wformat-extra-args
+If @option{-Wformat} is specified, do not warn about excess arguments to a
+@code{printf} or @code{scanf} format function.  The C standard specifies
+that such arguments are ignored.
+
+Where the unused arguments lie between used arguments that are
+specified with @samp{$} operand number specifications, normally
+warnings are still given, since the implementation could not know what
+type to pass to @code{va_arg} to skip the unused arguments.  However,
+in the case of @code{scanf} formats, this option suppresses the
+warning if the unused arguments are all pointers, since the Single
+Unix Specification says that such unused arguments are allowed.
+
+@item -Wno-format-zero-length
+@opindex Wno-format-zero-length
+@opindex Wformat-zero-length
+If @option{-Wformat} is specified, do not warn about zero-length formats.
+The C standard specifies that zero-length formats are allowed.
+
+
+@item -Wformat=2
+Enable @option{-Wformat} plus additional format checks.  Currently
+equivalent to @option{-Wformat -Wformat-nonliteral -Wformat-security
+-Wformat-y2k}.
+
+@item -Wformat-nonliteral
+@opindex Wformat-nonliteral
+@opindex Wno-format-nonliteral
+If @option{-Wformat} is specified, also warn if the format string is not a
+string literal and so cannot be checked, unless the format function
+takes its format arguments as a @code{va_list}.
+
+@item -Wformat-security
+@opindex Wformat-security
+@opindex Wno-format-security
+If @option{-Wformat} is specified, also warn about uses of format
+functions that represent possible security problems.  At present, this
+warns about calls to @code{printf} and @code{scanf} functions where the
+format string is not a string literal and there are no format arguments,
+as in @code{printf (foo);}.  This may be a security hole if the format
+string came from untrusted input and contains @samp{%n}.  (This is
+currently a subset of what @option{-Wformat-nonliteral} warns about, but
+in future warnings may be added to @option{-Wformat-security} that are not
+included in @option{-Wformat-nonliteral}.)
+
+@item -Wformat-y2k
+@opindex Wformat-y2k
+@opindex Wno-format-y2k
+If @option{-Wformat} is specified, also warn about @code{strftime}
+formats that may yield only a two-digit year.
+@end table
+
+@item -Wnonnull
+@opindex Wnonnull
+@opindex Wno-nonnull
+Warn about passing a null pointer for arguments marked as
+requiring a non-null value by the @code{nonnull} function attribute.
+
+@option{-Wnonnull} is included in @option{-Wall} and @option{-Wformat}.  It
+can be disabled with the @option{-Wno-nonnull} option.
+
+@item -Winit-self @r{(C, C++, Objective-C and Objective-C++ only)}
+@opindex Winit-self
+@opindex Wno-init-self
+Warn about uninitialized variables that are initialized with themselves.
+Note this option can only be used with the @option{-Wuninitialized} option.
+
+For example, GCC warns about @code{i} being uninitialized in the
+following snippet only when @option{-Winit-self} has been specified:
+@smallexample
+@group
+int f()
+@{
+  int i = i;
+  return i;
+@}
+@end group
+@end smallexample
+
+This warning is enabled by @option{-Wall} in C++.
+
+@item -Wimplicit-int @r{(C and Objective-C only)}
+@opindex Wimplicit-int
+@opindex Wno-implicit-int
+Warn when a declaration does not specify a type.
+This warning is enabled by @option{-Wall}.
+
+@item -Wimplicit-function-declaration @r{(C and Objective-C only)}
+@opindex Wimplicit-function-declaration
+@opindex Wno-implicit-function-declaration
+Give a warning whenever a function is used before being declared. In
+C99 mode (@option{-std=c99} or @option{-std=gnu99}), this warning is
+enabled by default and it is made into an error by
+@option{-pedantic-errors}. This warning is also enabled by
+@option{-Wall}.
+
+@item -Wimplicit @r{(C and Objective-C only)}
+@opindex Wimplicit
+@opindex Wno-implicit
+Same as @option{-Wimplicit-int} and @option{-Wimplicit-function-declaration}.
+This warning is enabled by @option{-Wall}.
+
+@item -Wignored-qualifiers @r{(C and C++ only)}
+@opindex Wignored-qualifiers
+@opindex Wno-ignored-qualifiers
+Warn if the return type of a function has a type qualifier
+such as @code{const}.  For ISO C such a type qualifier has no effect,
+since the value returned by a function is not an lvalue.
+For C++, the warning is only emitted for scalar types or @code{void}.
+ISO C prohibits qualified @code{void} return types on function
+definitions, so such return types always receive a warning
+even without this option.
+
+This warning is also enabled by @option{-Wextra}.
+
+@item -Wmain
+@opindex Wmain
+@opindex Wno-main
+Warn if the type of @samp{main} is suspicious.  @samp{main} should be
+a function with external linkage, returning int, taking either zero
+arguments, two, or three arguments of appropriate types.  This warning
+is enabled by default in C++ and is enabled by either @option{-Wall}
+or @option{-Wpedantic}.
+
+@item -Wmissing-braces
+@opindex Wmissing-braces
+@opindex Wno-missing-braces
+Warn if an aggregate or union initializer is not fully bracketed.  In
+the following example, the initializer for @samp{a} is not fully
+bracketed, but that for @samp{b} is fully bracketed.  This warning is
+enabled by @option{-Wall} in C.
+
+@smallexample
+int a[2][2] = @{ 0, 1, 2, 3 @};
+int b[2][2] = @{ @{ 0, 1 @}, @{ 2, 3 @} @};
+@end smallexample
+
+This warning is enabled by @option{-Wall}.
+
+@item -Wmissing-include-dirs @r{(C, C++, Objective-C and Objective-C++ only)}
+@opindex Wmissing-include-dirs
+@opindex Wno-missing-include-dirs
+Warn if a user-supplied include directory does not exist.
+
+@item -Wparentheses
+@opindex Wparentheses
+@opindex Wno-parentheses
+Warn if parentheses are omitted in certain contexts, such
+as when there is an assignment in a context where a truth value
+is expected, or when operators are nested whose precedence people
+often get confused about.
+
+Also warn if a comparison like @samp{x<=y<=z} appears; this is
+equivalent to @samp{(x<=y ? 1 : 0) <= z}, which is a different
+interpretation from that of ordinary mathematical notation.
+
+Also warn about constructions where there may be confusion to which
+@code{if} statement an @code{else} branch belongs.  Here is an example of
+such a case:
+
+@smallexample
+@group
+@{
+  if (a)
+    if (b)
+      foo ();
+  else
+    bar ();
+@}
+@end group
+@end smallexample
+
+In C/C++, every @code{else} branch belongs to the innermost possible
+@code{if} statement, which in this example is @code{if (b)}.  This is
+often not what the programmer expected, as illustrated in the above
+example by indentation the programmer chose.  When there is the
+potential for this confusion, GCC issues a warning when this flag
+is specified.  To eliminate the warning, add explicit braces around
+the innermost @code{if} statement so there is no way the @code{else}
+can belong to the enclosing @code{if}.  The resulting code
+looks like this:
+
+@smallexample
+@group
+@{
+  if (a)
+    @{
+      if (b)
+        foo ();
+      else
+        bar ();
+    @}
+@}
+@end group
+@end smallexample
+
+Also warn for dangerous uses of the GNU extension to
+@code{?:} with omitted middle operand. When the condition
+in the @code{?}: operator is a boolean expression, the omitted value is
+always 1.  Often programmers expect it to be a value computed
+inside the conditional expression instead.
+
+This warning is enabled by @option{-Wall}.
+
+@item -Wsequence-point
+@opindex Wsequence-point
+@opindex Wno-sequence-point
+Warn about code that may have undefined semantics because of violations
+of sequence point rules in the C and C++ standards.
+
+The C and C++ standards define the order in which expressions in a C/C++
+program are evaluated in terms of @dfn{sequence points}, which represent
+a partial ordering between the execution of parts of the program: those
+executed before the sequence point, and those executed after it.  These
+occur after the evaluation of a full expression (one which is not part
+of a larger expression), after the evaluation of the first operand of a
+@code{&&}, @code{||}, @code{? :} or @code{,} (comma) operator, before a
+function is called (but after the evaluation of its arguments and the
+expression denoting the called function), and in certain other places.
+Other than as expressed by the sequence point rules, the order of
+evaluation of subexpressions of an expression is not specified.  All
+these rules describe only a partial order rather than a total order,
+since, for example, if two functions are called within one expression
+with no sequence point between them, the order in which the functions
+are called is not specified.  However, the standards committee have
+ruled that function calls do not overlap.
+
+It is not specified when between sequence points modifications to the
+values of objects take effect.  Programs whose behavior depends on this
+have undefined behavior; the C and C++ standards specify that ``Between
+the previous and next sequence point an object shall have its stored
+value modified at most once by the evaluation of an expression.
+Furthermore, the prior value shall be read only to determine the value
+to be stored.''.  If a program breaks these rules, the results on any
+particular implementation are entirely unpredictable.
+
+Examples of code with undefined behavior are @code{a = a++;}, @code{a[n]
+= b[n++]} and @code{a[i++] = i;}.  Some more complicated cases are not
+diagnosed by this option, and it may give an occasional false positive
+result, but in general it has been found fairly effective at detecting
+this sort of problem in programs.
+
+The standard is worded confusingly, therefore there is some debate
+over the precise meaning of the sequence point rules in subtle cases.
+Links to discussions of the problem, including proposed formal
+definitions, may be found on the GCC readings page, at
+@uref{http://gcc.gnu.org/@/readings.html}.
+
+This warning is enabled by @option{-Wall} for C and C++.
+
+@item -Wno-return-local-addr
+@opindex Wno-return-local-addr
+@opindex Wreturn-local-addr
+Do not warn about returning a pointer (or in C++, a reference) to a
+variable that goes out of scope after the function returns.
+
+@item -Wreturn-type
+@opindex Wreturn-type
+@opindex Wno-return-type
+Warn whenever a function is defined with a return type that defaults
+to @code{int}.  Also warn about any @code{return} statement with no
+return value in a function whose return type is not @code{void}
+(falling off the end of the function body is considered returning
+without a value), and about a @code{return} statement with an
+expression in a function whose return type is @code{void}.
+
+For C++, a function without return type always produces a diagnostic
+message, even when @option{-Wno-return-type} is specified.  The only
+exceptions are @samp{main} and functions defined in system headers.
+
+This warning is enabled by @option{-Wall}.
+
+@item -Wswitch
+@opindex Wswitch
+@opindex Wno-switch
+Warn whenever a @code{switch} statement has an index of enumerated type
+and lacks a @code{case} for one or more of the named codes of that
+enumeration.  (The presence of a @code{default} label prevents this
+warning.)  @code{case} labels outside the enumeration range also
+provoke warnings when this option is used (even if there is a
+@code{default} label).
+This warning is enabled by @option{-Wall}.
+
+@item -Wswitch-default
+@opindex Wswitch-default
+@opindex Wno-switch-default
+Warn whenever a @code{switch} statement does not have a @code{default}
+case.
+
+@item -Wswitch-enum
+@opindex Wswitch-enum
+@opindex Wno-switch-enum
+Warn whenever a @code{switch} statement has an index of enumerated type
+and lacks a @code{case} for one or more of the named codes of that
+enumeration.  @code{case} labels outside the enumeration range also
+provoke warnings when this option is used.  The only difference
+between @option{-Wswitch} and this option is that this option gives a
+warning about an omitted enumeration code even if there is a
+@code{default} label.
+
+@item -Wsync-nand @r{(C and C++ only)}
+@opindex Wsync-nand
+@opindex Wno-sync-nand
+Warn when @code{__sync_fetch_and_nand} and @code{__sync_nand_and_fetch}
+built-in functions are used.  These functions changed semantics in GCC 4.4.
+
+@item -Wtrigraphs
+@opindex Wtrigraphs
+@opindex Wno-trigraphs
+Warn if any trigraphs are encountered that might change the meaning of
+the program (trigraphs within comments are not warned about).
+This warning is enabled by @option{-Wall}.
+
+@item -Wunused-but-set-parameter
+@opindex Wunused-but-set-parameter
+@opindex Wno-unused-but-set-parameter
+Warn whenever a function parameter is assigned to, but otherwise unused
+(aside from its declaration).
+
+To suppress this warning use the @samp{unused} attribute
+(@pxref{Variable Attributes}).
+
+This warning is also enabled by @option{-Wunused} together with
+@option{-Wextra}.
+
+@item -Wunused-but-set-variable
+@opindex Wunused-but-set-variable
+@opindex Wno-unused-but-set-variable
+Warn whenever a local variable is assigned to, but otherwise unused
+(aside from its declaration).
+This warning is enabled by @option{-Wall}.
+
+To suppress this warning use the @samp{unused} attribute
+(@pxref{Variable Attributes}).
+
+This warning is also enabled by @option{-Wunused}, which is enabled
+by @option{-Wall}.
+
+@item -Wunused-function
+@opindex Wunused-function
+@opindex Wno-unused-function
+Warn whenever a static function is declared but not defined or a
+non-inline static function is unused.
+This warning is enabled by @option{-Wall}.
+
+@item -Wunused-label
+@opindex Wunused-label
+@opindex Wno-unused-label
+Warn whenever a label is declared but not used.
+This warning is enabled by @option{-Wall}.
+
+To suppress this warning use the @samp{unused} attribute
+(@pxref{Variable Attributes}).
+
+@item -Wunused-local-typedefs @r{(C, Objective-C, C++ and Objective-C++ only)}
+@opindex Wunused-local-typedefs
+Warn when a typedef locally defined in a function is not used.
+This warning is enabled by @option{-Wall}.
+
+@item -Wunused-parameter
+@opindex Wunused-parameter
+@opindex Wno-unused-parameter
+Warn whenever a function parameter is unused aside from its declaration.
+
+To suppress this warning use the @samp{unused} attribute
+(@pxref{Variable Attributes}).
+
+@item -Wno-unused-result
+@opindex Wunused-result
+@opindex Wno-unused-result
+Do not warn if a caller of a function marked with attribute
+@code{warn_unused_result} (@pxref{Function Attributes}) does not use
+its return value. The default is @option{-Wunused-result}.
+
+@item -Wunused-variable
+@opindex Wunused-variable
+@opindex Wno-unused-variable
+Warn whenever a local variable or non-constant static variable is unused
+aside from its declaration.
+This warning is enabled by @option{-Wall}.
+
+To suppress this warning use the @samp{unused} attribute
+(@pxref{Variable Attributes}).
+
+@item -Wunused-value
+@opindex Wunused-value
+@opindex Wno-unused-value
+Warn whenever a statement computes a result that is explicitly not
+used. To suppress this warning cast the unused expression to
+@samp{void}. This includes an expression-statement or the left-hand
+side of a comma expression that contains no side effects. For example,
+an expression such as @samp{x[i,j]} causes a warning, while
+@samp{x[(void)i,j]} does not.
+
+This warning is enabled by @option{-Wall}.
+
+@item -Wunused
+@opindex Wunused
+@opindex Wno-unused
+All the above @option{-Wunused} options combined.
+
+In order to get a warning about an unused function parameter, you must
+either specify @option{-Wextra -Wunused} (note that @option{-Wall} implies
+@option{-Wunused}), or separately specify @option{-Wunused-parameter}.
+
+@item -Wuninitialized
+@opindex Wuninitialized
+@opindex Wno-uninitialized
+Warn if an automatic variable is used without first being initialized
+or if a variable may be clobbered by a @code{setjmp} call. In C++,
+warn if a non-static reference or non-static @samp{const} member
+appears in a class without constructors.
+
+If you want to warn about code that uses the uninitialized value of the
+variable in its own initializer, use the @option{-Winit-self} option.
+
+These warnings occur for individual uninitialized or clobbered
+elements of structure, union or array variables as well as for
+variables that are uninitialized or clobbered as a whole.  They do
+not occur for variables or elements declared @code{volatile}.  Because
+these warnings depend on optimization, the exact variables or elements
+for which there are warnings depends on the precise optimization
+options and version of GCC used.
+
+Note that there may be no warning about a variable that is used only
+to compute a value that itself is never used, because such
+computations may be deleted by data flow analysis before the warnings
+are printed.
+
+@item -Wmaybe-uninitialized
+@opindex Wmaybe-uninitialized
+@opindex Wno-maybe-uninitialized
+For an automatic variable, if there exists a path from the function
+entry to a use of the variable that is initialized, but there exist
+some other paths for which the variable is not initialized, the compiler
+emits a warning if it cannot prove the uninitialized paths are not
+executed at run time. These warnings are made optional because GCC is
+not smart enough to see all the reasons why the code might be correct
+in spite of appearing to have an error.  Here is one example of how
+this can happen:
+
+@smallexample
+@group
+@{
+  int x;
+  switch (y)
+    @{
+    case 1: x = 1;
+      break;
+    case 2: x = 4;
+      break;
+    case 3: x = 5;
+    @}
+  foo (x);
+@}
+@end group
+@end smallexample
+
+@noindent
+If the value of @code{y} is always 1, 2 or 3, then @code{x} is
+always initialized, but GCC doesn't know this. To suppress the
+warning, you need to provide a default case with assert(0) or
+similar code.
+
+@cindex @code{longjmp} warnings
+This option also warns when a non-volatile automatic variable might be
+changed by a call to @code{longjmp}.  These warnings as well are possible
+only in optimizing compilation.
+
+The compiler sees only the calls to @code{setjmp}.  It cannot know
+where @code{longjmp} will be called; in fact, a signal handler could
+call it at any point in the code.  As a result, you may get a warning
+even when there is in fact no problem because @code{longjmp} cannot
+in fact be called at the place that would cause a problem.
+
+Some spurious warnings can be avoided if you declare all the functions
+you use that never return as @code{noreturn}.  @xref{Function
+Attributes}.
+
+This warning is enabled by @option{-Wall} or @option{-Wextra}.
+
+@item -Wunknown-pragmas
+@opindex Wunknown-pragmas
+@opindex Wno-unknown-pragmas
+@cindex warning for unknown pragmas
+@cindex unknown pragmas, warning
+@cindex pragmas, warning of unknown
+Warn when a @code{#pragma} directive is encountered that is not understood by 
+GCC@.  If this command-line option is used, warnings are even issued
+for unknown pragmas in system header files.  This is not the case if
+the warnings are only enabled by the @option{-Wall} command-line option.
+
+@item -Wno-pragmas
+@opindex Wno-pragmas
+@opindex Wpragmas
+Do not warn about misuses of pragmas, such as incorrect parameters,
+invalid syntax, or conflicts between pragmas.  See also
+@option{-Wunknown-pragmas}.
+
+@item -Wstrict-aliasing
+@opindex Wstrict-aliasing
+@opindex Wno-strict-aliasing
+This option is only active when @option{-fstrict-aliasing} is active.
+It warns about code that might break the strict aliasing rules that the
+compiler is using for optimization.  The warning does not catch all
+cases, but does attempt to catch the more common pitfalls.  It is
+included in @option{-Wall}.
+It is equivalent to @option{-Wstrict-aliasing=3}
+
+@item -Wstrict-aliasing=n
+@opindex Wstrict-aliasing=n
+This option is only active when @option{-fstrict-aliasing} is active.
+It warns about code that might break the strict aliasing rules that the
+compiler is using for optimization.
+Higher levels correspond to higher accuracy (fewer false positives).
+Higher levels also correspond to more effort, similar to the way @option{-O} 
+works.
+@option{-Wstrict-aliasing} is equivalent to @option{-Wstrict-aliasing=3}.
+
+Level 1: Most aggressive, quick, least accurate.
+Possibly useful when higher levels
+do not warn but @option{-fstrict-aliasing} still breaks the code, as it has very few
+false negatives.  However, it has many false positives.
+Warns for all pointer conversions between possibly incompatible types,
+even if never dereferenced.  Runs in the front end only.
+
+Level 2: Aggressive, quick, not too precise.
+May still have many false positives (not as many as level 1 though),
+and few false negatives (but possibly more than level 1).
+Unlike level 1, it only warns when an address is taken.  Warns about
+incomplete types.  Runs in the front end only.
+
+Level 3 (default for @option{-Wstrict-aliasing}):
+Should have very few false positives and few false
+negatives.  Slightly slower than levels 1 or 2 when optimization is enabled.
+Takes care of the common pun+dereference pattern in the front end:
+@code{*(int*)&some_float}.
+If optimization is enabled, it also runs in the back end, where it deals
+with multiple statement cases using flow-sensitive points-to information.
+Only warns when the converted pointer is dereferenced.
+Does not warn about incomplete types.
+
+@item -Wstrict-overflow
+@itemx -Wstrict-overflow=@var{n}
+@opindex Wstrict-overflow
+@opindex Wno-strict-overflow
+This option is only active when @option{-fstrict-overflow} is active.
+It warns about cases where the compiler optimizes based on the
+assumption that signed overflow does not occur.  Note that it does not
+warn about all cases where the code might overflow: it only warns
+about cases where the compiler implements some optimization.  Thus
+this warning depends on the optimization level.
+
+An optimization that assumes that signed overflow does not occur is
+perfectly safe if the values of the variables involved are such that
+overflow never does, in fact, occur.  Therefore this warning can
+easily give a false positive: a warning about code that is not
+actually a problem.  To help focus on important issues, several
+warning levels are defined.  No warnings are issued for the use of
+undefined signed overflow when estimating how many iterations a loop
+requires, in particular when determining whether a loop will be
+executed at all.
+
+@table @gcctabopt
+@item -Wstrict-overflow=1
+Warn about cases that are both questionable and easy to avoid.  For
+example,  with @option{-fstrict-overflow}, the compiler simplifies
+@code{x + 1 > x} to @code{1}.  This level of
+@option{-Wstrict-overflow} is enabled by @option{-Wall}; higher levels
+are not, and must be explicitly requested.
+
+@item -Wstrict-overflow=2
+Also warn about other cases where a comparison is simplified to a
+constant.  For example: @code{abs (x) >= 0}.  This can only be
+simplified when @option{-fstrict-overflow} is in effect, because
+@code{abs (INT_MIN)} overflows to @code{INT_MIN}, which is less than
+zero.  @option{-Wstrict-overflow} (with no level) is the same as
+@option{-Wstrict-overflow=2}.
+
+@item -Wstrict-overflow=3
+Also warn about other cases where a comparison is simplified.  For
+example: @code{x + 1 > 1} is simplified to @code{x > 0}.
+
+@item -Wstrict-overflow=4
+Also warn about other simplifications not covered by the above cases.
+For example: @code{(x * 10) / 5} is simplified to @code{x * 2}.
+
+@item -Wstrict-overflow=5
+Also warn about cases where the compiler reduces the magnitude of a
+constant involved in a comparison.  For example: @code{x + 2 > y} is
+simplified to @code{x + 1 >= y}.  This is reported only at the
+highest warning level because this simplification applies to many
+comparisons, so this warning level gives a very large number of
+false positives.
+@end table
+
+@item -Wsuggest-attribute=@r{[}pure@r{|}const@r{|}noreturn@r{|}format@r{]}
+@opindex Wsuggest-attribute=
+@opindex Wno-suggest-attribute=
+Warn for cases where adding an attribute may be beneficial. The
+attributes currently supported are listed below.
+
+@table @gcctabopt
+@item -Wsuggest-attribute=pure
+@itemx -Wsuggest-attribute=const
+@itemx -Wsuggest-attribute=noreturn
+@opindex Wsuggest-attribute=pure
+@opindex Wno-suggest-attribute=pure
+@opindex Wsuggest-attribute=const
+@opindex Wno-suggest-attribute=const
+@opindex Wsuggest-attribute=noreturn
+@opindex Wno-suggest-attribute=noreturn
+
+Warn about functions that might be candidates for attributes
+@code{pure}, @code{const} or @code{noreturn}.  The compiler only warns for
+functions visible in other compilation units or (in the case of @code{pure} and
+@code{const}) if it cannot prove that the function returns normally. A function
+returns normally if it doesn't contain an infinite loop or return abnormally
+by throwing, calling @code{abort()} or trapping.  This analysis requires option
+@option{-fipa-pure-const}, which is enabled by default at @option{-O} and
+higher.  Higher optimization levels improve the accuracy of the analysis.
+
+@item -Wsuggest-attribute=format
+@itemx -Wmissing-format-attribute
+@opindex Wsuggest-attribute=format
+@opindex Wmissing-format-attribute
+@opindex Wno-suggest-attribute=format
+@opindex Wno-missing-format-attribute
+@opindex Wformat
+@opindex Wno-format
+
+Warn about function pointers that might be candidates for @code{format}
+attributes.  Note these are only possible candidates, not absolute ones.
+GCC guesses that function pointers with @code{format} attributes that
+are used in assignment, initialization, parameter passing or return
+statements should have a corresponding @code{format} attribute in the
+resulting type.  I.e.@: the left-hand side of the assignment or
+initialization, the type of the parameter variable, or the return type
+of the containing function respectively should also have a @code{format}
+attribute to avoid the warning.
+
+GCC also warns about function definitions that might be
+candidates for @code{format} attributes.  Again, these are only
+possible candidates.  GCC guesses that @code{format} attributes
+might be appropriate for any function that calls a function like
+@code{vprintf} or @code{vscanf}, but this might not always be the
+case, and some functions for which @code{format} attributes are
+appropriate may not be detected.
+@end table
+
+@item -Warray-bounds
+@opindex Wno-array-bounds
+@opindex Warray-bounds
+This option is only active when @option{-ftree-vrp} is active
+(default for @option{-O2} and above). It warns about subscripts to arrays
+that are always out of bounds. This warning is enabled by @option{-Wall}.
+
+@item -Wno-div-by-zero
+@opindex Wno-div-by-zero
+@opindex Wdiv-by-zero
+Do not warn about compile-time integer division by zero.  Floating-point
+division by zero is not warned about, as it can be a legitimate way of
+obtaining infinities and NaNs.
+
+@item -Wsystem-headers
+@opindex Wsystem-headers
+@opindex Wno-system-headers
+@cindex warnings from system headers
+@cindex system headers, warnings from
+Print warning messages for constructs found in system header files.
+Warnings from system headers are normally suppressed, on the assumption
+that they usually do not indicate real problems and would only make the
+compiler output harder to read.  Using this command-line option tells
+GCC to emit warnings from system headers as if they occurred in user
+code.  However, note that using @option{-Wall} in conjunction with this
+option does @emph{not} warn about unknown pragmas in system
+headers---for that, @option{-Wunknown-pragmas} must also be used.
+
+@item -Wtrampolines
+@opindex Wtrampolines
+@opindex Wno-trampolines
+ Warn about trampolines generated for pointers to nested functions.
+
+ A trampoline is a small piece of data or code that is created at run
+ time on the stack when the address of a nested function is taken, and
+ is used to call the nested function indirectly.  For some targets, it
+ is made up of data only and thus requires no special treatment.  But,
+ for most targets, it is made up of code and thus requires the stack
+ to be made executable in order for the program to work properly.
+
+@item -Wfloat-equal
+@opindex Wfloat-equal
+@opindex Wno-float-equal
+Warn if floating-point values are used in equality comparisons.
+
+The idea behind this is that sometimes it is convenient (for the
+programmer) to consider floating-point values as approximations to
+infinitely precise real numbers.  If you are doing this, then you need
+to compute (by analyzing the code, or in some other way) the maximum or
+likely maximum error that the computation introduces, and allow for it
+when performing comparisons (and when producing output, but that's a
+different problem).  In particular, instead of testing for equality, you
+should check to see whether the two values have ranges that overlap; and
+this is done with the relational operators, so equality comparisons are
+probably mistaken.
+
+@item -Wtraditional @r{(C and Objective-C only)}
+@opindex Wtraditional
+@opindex Wno-traditional
+Warn about certain constructs that behave differently in traditional and
+ISO C@.  Also warn about ISO C constructs that have no traditional C
+equivalent, and/or problematic constructs that should be avoided.
+
+@itemize @bullet
+@item
+Macro parameters that appear within string literals in the macro body.
+In traditional C macro replacement takes place within string literals,
+but in ISO C it does not.
+
+@item
+In traditional C, some preprocessor directives did not exist.
+Traditional preprocessors only considered a line to be a directive
+if the @samp{#} appeared in column 1 on the line.  Therefore
+@option{-Wtraditional} warns about directives that traditional C
+understands but ignores because the @samp{#} does not appear as the
+first character on the line.  It also suggests you hide directives like
+@samp{#pragma} not understood by traditional C by indenting them.  Some
+traditional implementations do not recognize @samp{#elif}, so this option
+suggests avoiding it altogether.
+
+@item
+A function-like macro that appears without arguments.
+
+@item
+The unary plus operator.
+
+@item
+The @samp{U} integer constant suffix, or the @samp{F} or @samp{L} floating-point
+constant suffixes.  (Traditional C does support the @samp{L} suffix on integer
+constants.)  Note, these suffixes appear in macros defined in the system
+headers of most modern systems, e.g.@: the @samp{_MIN}/@samp{_MAX} macros in @code{<limits.h>}.
+Use of these macros in user code might normally lead to spurious
+warnings, however GCC's integrated preprocessor has enough context to
+avoid warning in these cases.
+
+@item
+A function declared external in one block and then used after the end of
+the block.
+
+@item
+A @code{switch} statement has an operand of type @code{long}.
+
+@item
+A non-@code{static} function declaration follows a @code{static} one.
+This construct is not accepted by some traditional C compilers.
+
+@item
+The ISO type of an integer constant has a different width or
+signedness from its traditional type.  This warning is only issued if
+the base of the constant is ten.  I.e.@: hexadecimal or octal values, which
+typically represent bit patterns, are not warned about.
+
+@item
+Usage of ISO string concatenation is detected.
+
+@item
+Initialization of automatic aggregates.
+
+@item
+Identifier conflicts with labels.  Traditional C lacks a separate
+namespace for labels.
+
+@item
+Initialization of unions.  If the initializer is zero, the warning is
+omitted.  This is done under the assumption that the zero initializer in
+user code appears conditioned on e.g.@: @code{__STDC__} to avoid missing
+initializer warnings and relies on default initialization to zero in the
+traditional C case.
+
+@item
+Conversions by prototypes between fixed/floating-point values and vice
+versa.  The absence of these prototypes when compiling with traditional
+C causes serious problems.  This is a subset of the possible
+conversion warnings; for the full set use @option{-Wtraditional-conversion}.
+
+@item
+Use of ISO C style function definitions.  This warning intentionally is
+@emph{not} issued for prototype declarations or variadic functions
+because these ISO C features appear in your code when using
+libiberty's traditional C compatibility macros, @code{PARAMS} and
+@code{VPARAMS}.  This warning is also bypassed for nested functions
+because that feature is already a GCC extension and thus not relevant to
+traditional C compatibility.
+@end itemize
+
+@item -Wtraditional-conversion @r{(C and Objective-C only)}
+@opindex Wtraditional-conversion
+@opindex Wno-traditional-conversion
+Warn if a prototype causes a type conversion that is different from what
+would happen to the same argument in the absence of a prototype.  This
+includes conversions of fixed point to floating and vice versa, and
+conversions changing the width or signedness of a fixed-point argument
+except when the same as the default promotion.
+
+@item -Wdeclaration-after-statement @r{(C and Objective-C only)}
+@opindex Wdeclaration-after-statement
+@opindex Wno-declaration-after-statement
+Warn when a declaration is found after a statement in a block.  This
+construct, known from C++, was introduced with ISO C99 and is by default
+allowed in GCC@.  It is not supported by ISO C90 and was not supported by
+GCC versions before GCC 3.0.  @xref{Mixed Declarations}.
+
+@item -Wundef
+@opindex Wundef
+@opindex Wno-undef
+Warn if an undefined identifier is evaluated in an @samp{#if} directive.
+
+@item -Wno-endif-labels
+@opindex Wno-endif-labels
+@opindex Wendif-labels
+Do not warn whenever an @samp{#else} or an @samp{#endif} are followed by text.
+
+@item -Wshadow
+@opindex Wshadow
+@opindex Wno-shadow
+Warn whenever a local variable or type declaration shadows another variable,
+parameter, type, or class member (in C++), or whenever a built-in function
+is shadowed. Note that in C++, the compiler warns if a local variable
+shadows an explicit typedef, but not if it shadows a struct/class/enum.
+
+@item -Wlarger-than=@var{len}
+@opindex Wlarger-than=@var{len}
+@opindex Wlarger-than-@var{len}
+Warn whenever an object of larger than @var{len} bytes is defined.
+
+@item -Wframe-larger-than=@var{len}
+@opindex Wframe-larger-than
+Warn if the size of a function frame is larger than @var{len} bytes.
+The computation done to determine the stack frame size is approximate
+and not conservative.
+The actual requirements may be somewhat greater than @var{len}
+even if you do not get a warning.  In addition, any space allocated
+via @code{alloca}, variable-length arrays, or related constructs
+is not included by the compiler when determining
+whether or not to issue a warning.
+
+@item -Wno-free-nonheap-object
+@opindex Wno-free-nonheap-object
+@opindex Wfree-nonheap-object
+Do not warn when attempting to free an object that was not allocated
+on the heap.
+
+@item -Wstack-usage=@var{len}
+@opindex Wstack-usage
+Warn if the stack usage of a function might be larger than @var{len} bytes.
+The computation done to determine the stack usage is conservative.
+Any space allocated via @code{alloca}, variable-length arrays, or related
+constructs is included by the compiler when determining whether or not to
+issue a warning.
+
+The message is in keeping with the output of @option{-fstack-usage}.
+
+@itemize
+@item
+If the stack usage is fully static but exceeds the specified amount, it's:
+
+@smallexample
+  warning: stack usage is 1120 bytes
+@end smallexample
+@item
+If the stack usage is (partly) dynamic but bounded, it's:
+
+@smallexample
+  warning: stack usage might be 1648 bytes
+@end smallexample
+@item
+If the stack usage is (partly) dynamic and not bounded, it's:
+
+@smallexample
+  warning: stack usage might be unbounded
+@end smallexample
+@end itemize
+
+@item -Wunsafe-loop-optimizations
+@opindex Wunsafe-loop-optimizations
+@opindex Wno-unsafe-loop-optimizations
+Warn if the loop cannot be optimized because the compiler cannot
+assume anything on the bounds of the loop indices.  With
+@option{-funsafe-loop-optimizations} warn if the compiler makes
+such assumptions.
+
+@item -Wno-pedantic-ms-format @r{(MinGW targets only)}
+@opindex Wno-pedantic-ms-format
+@opindex Wpedantic-ms-format
+When used in combination with @option{-Wformat}
+and @option{-pedantic} without GNU extensions, this option
+disables the warnings about non-ISO @code{printf} / @code{scanf} format
+width specifiers @code{I32}, @code{I64}, and @code{I} used on Windows targets,
+which depend on the MS runtime.
+
+@item -Wpointer-arith
+@opindex Wpointer-arith
+@opindex Wno-pointer-arith
+Warn about anything that depends on the ``size of'' a function type or
+of @code{void}.  GNU C assigns these types a size of 1, for
+convenience in calculations with @code{void *} pointers and pointers
+to functions.  In C++, warn also when an arithmetic operation involves
+@code{NULL}.  This warning is also enabled by @option{-Wpedantic}.
+
+@item -Wtype-limits
+@opindex Wtype-limits
+@opindex Wno-type-limits
+Warn if a comparison is always true or always false due to the limited
+range of the data type, but do not warn for constant expressions.  For
+example, warn if an unsigned variable is compared against zero with
+@samp{<} or @samp{>=}.  This warning is also enabled by
+@option{-Wextra}.
+
+@item -Wbad-function-cast @r{(C and Objective-C only)}
+@opindex Wbad-function-cast
+@opindex Wno-bad-function-cast
+Warn whenever a function call is cast to a non-matching type.
+For example, warn if @code{int malloc()} is cast to @code{anything *}.
+
+@item -Wc++-compat @r{(C and Objective-C only)}
+Warn about ISO C constructs that are outside of the common subset of
+ISO C and ISO C++, e.g.@: request for implicit conversion from
+@code{void *} to a pointer to non-@code{void} type.
+
+@item -Wc++11-compat @r{(C++ and Objective-C++ only)}
+Warn about C++ constructs whose meaning differs between ISO C++ 1998
+and ISO C++ 2011, e.g., identifiers in ISO C++ 1998 that are keywords
+in ISO C++ 2011.  This warning turns on @option{-Wnarrowing} and is
+enabled by @option{-Wall}.
+
+@item -Wcast-qual
+@opindex Wcast-qual
+@opindex Wno-cast-qual
+Warn whenever a pointer is cast so as to remove a type qualifier from
+the target type.  For example, warn if a @code{const char *} is cast
+to an ordinary @code{char *}.
+
+Also warn when making a cast that introduces a type qualifier in an
+unsafe way.  For example, casting @code{char **} to @code{const char **}
+is unsafe, as in this example:
+
+@smallexample
+  /* p is char ** value.  */
+  const char **q = (const char **) p;
+  /* Assignment of readonly string to const char * is OK.  */
+  *q = "string";
+  /* Now char** pointer points to read-only memory.  */
+  **p = 'b';
+@end smallexample
+
+@item -Wcast-align
+@opindex Wcast-align
+@opindex Wno-cast-align
+Warn whenever a pointer is cast such that the required alignment of the
+target is increased.  For example, warn if a @code{char *} is cast to
+an @code{int *} on machines where integers can only be accessed at
+two- or four-byte boundaries.
+
+@item -Wwrite-strings
+@opindex Wwrite-strings
+@opindex Wno-write-strings
+When compiling C, give string constants the type @code{const
+char[@var{length}]} so that copying the address of one into a
+non-@code{const} @code{char *} pointer produces a warning.  These
+warnings help you find at compile time code that can try to write
+into a string constant, but only if you have been very careful about
+using @code{const} in declarations and prototypes.  Otherwise, it is
+just a nuisance. This is why we did not make @option{-Wall} request
+these warnings.
+
+When compiling C++, warn about the deprecated conversion from string
+literals to @code{char *}.  This warning is enabled by default for C++
+programs.
+
+@item -Wclobbered
+@opindex Wclobbered
+@opindex Wno-clobbered
+Warn for variables that might be changed by @samp{longjmp} or
+@samp{vfork}.  This warning is also enabled by @option{-Wextra}.
+
+@item -Wconversion
+@opindex Wconversion
+@opindex Wno-conversion
+Warn for implicit conversions that may alter a value. This includes
+conversions between real and integer, like @code{abs (x)} when
+@code{x} is @code{double}; conversions between signed and unsigned,
+like @code{unsigned ui = -1}; and conversions to smaller types, like
+@code{sqrtf (M_PI)}. Do not warn for explicit casts like @code{abs
+((int) x)} and @code{ui = (unsigned) -1}, or if the value is not
+changed by the conversion like in @code{abs (2.0)}.  Warnings about
+conversions between signed and unsigned integers can be disabled by
+using @option{-Wno-sign-conversion}.
+
+For C++, also warn for confusing overload resolution for user-defined
+conversions; and conversions that never use a type conversion
+operator: conversions to @code{void}, the same type, a base class or a
+reference to them. Warnings about conversions between signed and
+unsigned integers are disabled by default in C++ unless
+@option{-Wsign-conversion} is explicitly enabled.
+
+@item -Wno-conversion-null @r{(C++ and Objective-C++ only)}
+@opindex Wconversion-null
+@opindex Wno-conversion-null
+Do not warn for conversions between @code{NULL} and non-pointer
+types. @option{-Wconversion-null} is enabled by default.
+
+@item -Wzero-as-null-pointer-constant @r{(C++ and Objective-C++ only)}
+@opindex Wzero-as-null-pointer-constant
+@opindex Wno-zero-as-null-pointer-constant
+Warn when a literal '0' is used as null pointer constant.  This can
+be useful to facilitate the conversion to @code{nullptr} in C++11.
+
+@item -Wuseless-cast @r{(C++ and Objective-C++ only)}
+@opindex Wuseless-cast
+@opindex Wno-useless-cast
+Warn when an expression is casted to its own type.
+
+@item -Wempty-body
+@opindex Wempty-body
+@opindex Wno-empty-body
+Warn if an empty body occurs in an @samp{if}, @samp{else} or @samp{do
+while} statement.  This warning is also enabled by @option{-Wextra}.
+
+@item -Wenum-compare
+@opindex Wenum-compare
+@opindex Wno-enum-compare
+Warn about a comparison between values of different enumerated types.
+In C++ enumeral mismatches in conditional expressions are also
+diagnosed and the warning is enabled by default.  In C this warning is 
+enabled by @option{-Wall}.
+
+@item -Wjump-misses-init @r{(C, Objective-C only)}
+@opindex Wjump-misses-init
+@opindex Wno-jump-misses-init
+Warn if a @code{goto} statement or a @code{switch} statement jumps
+forward across the initialization of a variable, or jumps backward to a
+label after the variable has been initialized.  This only warns about
+variables that are initialized when they are declared.  This warning is
+only supported for C and Objective-C; in C++ this sort of branch is an
+error in any case.
+
+@option{-Wjump-misses-init} is included in @option{-Wc++-compat}.  It
+can be disabled with the @option{-Wno-jump-misses-init} option.
+
+@item -Wsign-compare
+@opindex Wsign-compare
+@opindex Wno-sign-compare
+@cindex warning for comparison of signed and unsigned values
+@cindex comparison of signed and unsigned values, warning
+@cindex signed and unsigned values, comparison warning
+Warn when a comparison between signed and unsigned values could produce
+an incorrect result when the signed value is converted to unsigned.
+This warning is also enabled by @option{-Wextra}; to get the other warnings
+of @option{-Wextra} without this warning, use @option{-Wextra -Wno-sign-compare}.
+
+@item -Wsign-conversion
+@opindex Wsign-conversion
+@opindex Wno-sign-conversion
+Warn for implicit conversions that may change the sign of an integer
+value, like assigning a signed integer expression to an unsigned
+integer variable. An explicit cast silences the warning. In C, this
+option is enabled also by @option{-Wconversion}.
+
+@item -Wsizeof-pointer-memaccess
+@opindex Wsizeof-pointer-memaccess
+@opindex Wno-sizeof-pointer-memaccess
+Warn for suspicious length parameters to certain string and memory built-in
+functions if the argument uses @code{sizeof}.  This warning warns e.g.@:
+about @code{memset (ptr, 0, sizeof (ptr));} if @code{ptr} is not an array,
+but a pointer, and suggests a possible fix, or about
+@code{memcpy (&foo, ptr, sizeof (&foo));}.  This warning is enabled by
+@option{-Wall}.
+
+@item -Waddress
+@opindex Waddress
+@opindex Wno-address
+Warn about suspicious uses of memory addresses. These include using
+the address of a function in a conditional expression, such as
+@code{void func(void); if (func)}, and comparisons against the memory
+address of a string literal, such as @code{if (x == "abc")}.  Such
+uses typically indicate a programmer error: the address of a function
+always evaluates to true, so their use in a conditional usually
+indicate that the programmer forgot the parentheses in a function
+call; and comparisons against string literals result in unspecified
+behavior and are not portable in C, so they usually indicate that the
+programmer intended to use @code{strcmp}.  This warning is enabled by
+@option{-Wall}.
+
+@item -Wlogical-op
+@opindex Wlogical-op
+@opindex Wno-logical-op
+Warn about suspicious uses of logical operators in expressions.
+This includes using logical operators in contexts where a
+bit-wise operator is likely to be expected.
+
+@item -Waggregate-return
+@opindex Waggregate-return
+@opindex Wno-aggregate-return
+Warn if any functions that return structures or unions are defined or
+called.  (In languages where you can return an array, this also elicits
+a warning.)
+
+@item -Wno-aggressive-loop-optimizations
+@opindex Wno-aggressive-loop-optimizations
+@opindex Waggressive-loop-optimizations
+Warn if in a loop with constant number of iterations the compiler detects
+undefined behavior in some statement during one or more of the iterations.
+
+@item -Wno-attributes
+@opindex Wno-attributes
+@opindex Wattributes
+Do not warn if an unexpected @code{__attribute__} is used, such as
+unrecognized attributes, function attributes applied to variables,
+etc.  This does not stop errors for incorrect use of supported
+attributes.
+
+@item -Wno-builtin-macro-redefined
+@opindex Wno-builtin-macro-redefined
+@opindex Wbuiltin-macro-redefined
+Do not warn if certain built-in macros are redefined.  This suppresses
+warnings for redefinition of @code{__TIMESTAMP__}, @code{__TIME__},
+@code{__DATE__}, @code{__FILE__}, and @code{__BASE_FILE__}.
+
+@item -Wstrict-prototypes @r{(C and Objective-C only)}
+@opindex Wstrict-prototypes
+@opindex Wno-strict-prototypes
+Warn if a function is declared or defined without specifying the
+argument types.  (An old-style function definition is permitted without
+a warning if preceded by a declaration that specifies the argument
+types.)
+
+@item -Wold-style-declaration @r{(C and Objective-C only)}
+@opindex Wold-style-declaration
+@opindex Wno-old-style-declaration
+Warn for obsolescent usages, according to the C Standard, in a
+declaration. For example, warn if storage-class specifiers like
+@code{static} are not the first things in a declaration.  This warning
+is also enabled by @option{-Wextra}.
+
+@item -Wold-style-definition @r{(C and Objective-C only)}
+@opindex Wold-style-definition
+@opindex Wno-old-style-definition
+Warn if an old-style function definition is used.  A warning is given
+even if there is a previous prototype.
+
+@item -Wmissing-parameter-type @r{(C and Objective-C only)}
+@opindex Wmissing-parameter-type
+@opindex Wno-missing-parameter-type
+A function parameter is declared without a type specifier in K&R-style
+functions:
+
+@smallexample
+void foo(bar) @{ @}
+@end smallexample
+
+This warning is also enabled by @option{-Wextra}.
+
+@item -Wmissing-prototypes @r{(C and Objective-C only)}
+@opindex Wmissing-prototypes
+@opindex Wno-missing-prototypes
+Warn if a global function is defined without a previous prototype
+declaration.  This warning is issued even if the definition itself
+provides a prototype.  Use this option to detect global functions
+that do not have a matching prototype declaration in a header file.
+This option is not valid for C++ because all function declarations
+provide prototypes and a non-matching declaration will declare an
+overload rather than conflict with an earlier declaration.
+Use @option{-Wmissing-declarations} to detect missing declarations in C++.
+
+@item -Wmissing-declarations
+@opindex Wmissing-declarations
+@opindex Wno-missing-declarations
+Warn if a global function is defined without a previous declaration.
+Do so even if the definition itself provides a prototype.
+Use this option to detect global functions that are not declared in
+header files.  In C, no warnings are issued for functions with previous
+non-prototype declarations; use @option{-Wmissing-prototype} to detect
+missing prototypes.  In C++, no warnings are issued for function templates,
+or for inline functions, or for functions in anonymous namespaces.
+
+@item -Wmissing-field-initializers
+@opindex Wmissing-field-initializers
+@opindex Wno-missing-field-initializers
+@opindex W
+@opindex Wextra
+@opindex Wno-extra
+Warn if a structure's initializer has some fields missing.  For
+example, the following code causes such a warning, because
+@code{x.h} is implicitly zero:
+
+@smallexample
+struct s @{ int f, g, h; @};
+struct s x = @{ 3, 4 @};
+@end smallexample
+
+This option does not warn about designated initializers, so the following
+modification does not trigger a warning:
+
+@smallexample
+struct s @{ int f, g, h; @};
+struct s x = @{ .f = 3, .g = 4 @};
+@end smallexample
+
+This warning is included in @option{-Wextra}.  To get other @option{-Wextra}
+warnings without this one, use @option{-Wextra -Wno-missing-field-initializers}.
+
+@item -Wno-multichar
+@opindex Wno-multichar
+@opindex Wmultichar
+Do not warn if a multicharacter constant (@samp{'FOOF'}) is used.
+Usually they indicate a typo in the user's code, as they have
+implementation-defined values, and should not be used in portable code.
+
+@item -Wnormalized=<none|id|nfc|nfkc>
+@opindex Wnormalized=
+@cindex NFC
+@cindex NFKC
+@cindex character set, input normalization
+In ISO C and ISO C++, two identifiers are different if they are
+different sequences of characters.  However, sometimes when characters
+outside the basic ASCII character set are used, you can have two
+different character sequences that look the same.  To avoid confusion,
+the ISO 10646 standard sets out some @dfn{normalization rules} which
+when applied ensure that two sequences that look the same are turned into
+the same sequence.  GCC can warn you if you are using identifiers that
+have not been normalized; this option controls that warning.
+
+There are four levels of warning supported by GCC@.  The default is
+@option{-Wnormalized=nfc}, which warns about any identifier that is
+not in the ISO 10646 ``C'' normalized form, @dfn{NFC}.  NFC is the
+recommended form for most uses.
+
+Unfortunately, there are some characters allowed in identifiers by
+ISO C and ISO C++ that, when turned into NFC, are not allowed in 
+identifiers.  That is, there's no way to use these symbols in portable
+ISO C or C++ and have all your identifiers in NFC@.
+@option{-Wnormalized=id} suppresses the warning for these characters.
+It is hoped that future versions of the standards involved will correct
+this, which is why this option is not the default.
+
+You can switch the warning off for all characters by writing
+@option{-Wnormalized=none}.  You should only do this if you
+are using some other normalization scheme (like ``D''), because
+otherwise you can easily create bugs that are literally impossible to see.
+
+Some characters in ISO 10646 have distinct meanings but look identical
+in some fonts or display methodologies, especially once formatting has
+been applied.  For instance @code{\u207F}, ``SUPERSCRIPT LATIN SMALL
+LETTER N'', displays just like a regular @code{n} that has been
+placed in a superscript.  ISO 10646 defines the @dfn{NFKC}
+normalization scheme to convert all these into a standard form as
+well, and GCC warns if your code is not in NFKC if you use
+@option{-Wnormalized=nfkc}.  This warning is comparable to warning
+about every identifier that contains the letter O because it might be
+confused with the digit 0, and so is not the default, but may be
+useful as a local coding convention if the programming environment 
+cannot be fixed to display these characters distinctly.
+
+@item -Wno-deprecated
+@opindex Wno-deprecated
+@opindex Wdeprecated
+Do not warn about usage of deprecated features.  @xref{Deprecated Features}.
+
+@item -Wno-deprecated-declarations
+@opindex Wno-deprecated-declarations
+@opindex Wdeprecated-declarations
+Do not warn about uses of functions (@pxref{Function Attributes}),
+variables (@pxref{Variable Attributes}), and types (@pxref{Type
+Attributes}) marked as deprecated by using the @code{deprecated}
+attribute.
+
+@item -Wno-overflow
+@opindex Wno-overflow
+@opindex Woverflow
+Do not warn about compile-time overflow in constant expressions.
+
+@item -Woverride-init @r{(C and Objective-C only)}
+@opindex Woverride-init
+@opindex Wno-override-init
+@opindex W
+@opindex Wextra
+@opindex Wno-extra
+Warn if an initialized field without side effects is overridden when
+using designated initializers (@pxref{Designated Inits, , Designated
+Initializers}).
+
+This warning is included in @option{-Wextra}.  To get other
+@option{-Wextra} warnings without this one, use @option{-Wextra
+-Wno-override-init}.
+
+@item -Wpacked
+@opindex Wpacked
+@opindex Wno-packed
+Warn if a structure is given the packed attribute, but the packed
+attribute has no effect on the layout or size of the structure.
+Such structures may be mis-aligned for little benefit.  For
+instance, in this code, the variable @code{f.x} in @code{struct bar}
+is misaligned even though @code{struct bar} does not itself
+have the packed attribute:
+
+@smallexample
+@group
+struct foo @{
+  int x;
+  char a, b, c, d;
+@} __attribute__((packed));
+struct bar @{
+  char z;
+  struct foo f;
+@};
+@end group
+@end smallexample
+
+@item -Wpacked-bitfield-compat
+@opindex Wpacked-bitfield-compat
+@opindex Wno-packed-bitfield-compat
+The 4.1, 4.2 and 4.3 series of GCC ignore the @code{packed} attribute
+on bit-fields of type @code{char}.  This has been fixed in GCC 4.4 but
+the change can lead to differences in the structure layout.  GCC
+informs you when the offset of such a field has changed in GCC 4.4.
+For example there is no longer a 4-bit padding between field @code{a}
+and @code{b} in this structure:
+
+@smallexample
+struct foo
+@{
+  char a:4;
+  char b:8;
+@} __attribute__ ((packed));
+@end smallexample
+
+This warning is enabled by default.  Use
+@option{-Wno-packed-bitfield-compat} to disable this warning.
+
+@item -Wpadded
+@opindex Wpadded
+@opindex Wno-padded
+Warn if padding is included in a structure, either to align an element
+of the structure or to align the whole structure.  Sometimes when this
+happens it is possible to rearrange the fields of the structure to
+reduce the padding and so make the structure smaller.
+
+@item -Wredundant-decls
+@opindex Wredundant-decls
+@opindex Wno-redundant-decls
+Warn if anything is declared more than once in the same scope, even in
+cases where multiple declaration is valid and changes nothing.
+
+@item -Wnested-externs @r{(C and Objective-C only)}
+@opindex Wnested-externs
+@opindex Wno-nested-externs
+Warn if an @code{extern} declaration is encountered within a function.
+
+@item -Wno-inherited-variadic-ctor
+@opindex Winherited-variadic-ctor
+@opindex Wno-inherited-variadic-ctor
+Suppress warnings about use of C++11 inheriting constructors when the
+base class inherited from has a C variadic constructor; the warning is
+on by default because the ellipsis is not inherited.
+
+@item -Winline
+@opindex Winline
+@opindex Wno-inline
+Warn if a function that is declared as inline cannot be inlined.
+Even with this option, the compiler does not warn about failures to
+inline functions declared in system headers.
+
+The compiler uses a variety of heuristics to determine whether or not
+to inline a function.  For example, the compiler takes into account
+the size of the function being inlined and the amount of inlining
+that has already been done in the current function.  Therefore,
+seemingly insignificant changes in the source program can cause the
+warnings produced by @option{-Winline} to appear or disappear.
+
+@item -Wno-invalid-offsetof @r{(C++ and Objective-C++ only)}
+@opindex Wno-invalid-offsetof
+@opindex Winvalid-offsetof
+Suppress warnings from applying the @samp{offsetof} macro to a non-POD
+type.  According to the 1998 ISO C++ standard, applying @samp{offsetof}
+to a non-POD type is undefined.  In existing C++ implementations,
+however, @samp{offsetof} typically gives meaningful results even when
+applied to certain kinds of non-POD types (such as a simple
+@samp{struct} that fails to be a POD type only by virtue of having a
+constructor).  This flag is for users who are aware that they are
+writing nonportable code and who have deliberately chosen to ignore the
+warning about it.
+
+The restrictions on @samp{offsetof} may be relaxed in a future version
+of the C++ standard.
+
+@item -Wno-int-to-pointer-cast
+@opindex Wno-int-to-pointer-cast
+@opindex Wint-to-pointer-cast
+Suppress warnings from casts to pointer type of an integer of a
+different size. In C++, casting to a pointer type of smaller size is
+an error. @option{Wint-to-pointer-cast} is enabled by default.
+
+
+@item -Wno-pointer-to-int-cast @r{(C and Objective-C only)}
+@opindex Wno-pointer-to-int-cast
+@opindex Wpointer-to-int-cast
+Suppress warnings from casts from a pointer to an integer type of a
+different size.
+
+@item -Winvalid-pch
+@opindex Winvalid-pch
+@opindex Wno-invalid-pch
+Warn if a precompiled header (@pxref{Precompiled Headers}) is found in
+the search path but can't be used.
+
+@item -Wlong-long
+@opindex Wlong-long
+@opindex Wno-long-long
+Warn if @samp{long long} type is used.  This is enabled by either
+@option{-Wpedantic} or @option{-Wtraditional} in ISO C90 and C++98
+modes.  To inhibit the warning messages, use @option{-Wno-long-long}.
+
+@item -Wvariadic-macros
+@opindex Wvariadic-macros
+@opindex Wno-variadic-macros
+Warn if variadic macros are used in pedantic ISO C90 mode, or the GNU
+alternate syntax when in pedantic ISO C99 mode.  This is default.
+To inhibit the warning messages, use @option{-Wno-variadic-macros}.
+
+@item -Wvarargs
+@opindex Wvarargs
+@opindex Wno-varargs
+Warn upon questionable usage of the macros used to handle variable
+arguments like @samp{va_start}.  This is default.  To inhibit the
+warning messages, use @option{-Wno-varargs}.
+
+@item -Wvector-operation-performance
+@opindex Wvector-operation-performance
+@opindex Wno-vector-operation-performance
+Warn if vector operation is not implemented via SIMD capabilities of the
+architecture.  Mainly useful for the performance tuning.
+Vector operation can be implemented @code{piecewise}, which means that the
+scalar operation is performed on every vector element; 
+@code{in parallel}, which means that the vector operation is implemented
+using scalars of wider type, which normally is more performance efficient;
+and @code{as a single scalar}, which means that vector fits into a
+scalar type.
+
+@item -Wno-virtual-move-assign
+@opindex Wvirtual-move-assign
+@opindex Wno-virtual-move-assign
+Suppress warnings about inheriting from a virtual base with a
+non-trivial C++11 move assignment operator.  This is dangerous because
+if the virtual base is reachable along more than one path, it will be
+moved multiple times, which can mean both objects end up in the
+moved-from state.  If the move assignment operator is written to avoid
+moving from a moved-from object, this warning can be disabled.
+
+@item -Wvla
+@opindex Wvla
+@opindex Wno-vla
+Warn if variable length array is used in the code.
+@option{-Wno-vla} prevents the @option{-Wpedantic} warning of
+the variable length array.
+
+@item -Wvolatile-register-var
+@opindex Wvolatile-register-var
+@opindex Wno-volatile-register-var
+Warn if a register variable is declared volatile.  The volatile
+modifier does not inhibit all optimizations that may eliminate reads
+and/or writes to register variables.  This warning is enabled by
+@option{-Wall}.
+
+@item -Wdisabled-optimization
+@opindex Wdisabled-optimization
+@opindex Wno-disabled-optimization
+Warn if a requested optimization pass is disabled.  This warning does
+not generally indicate that there is anything wrong with your code; it
+merely indicates that GCC's optimizers are unable to handle the code
+effectively.  Often, the problem is that your code is too big or too
+complex; GCC refuses to optimize programs when the optimization
+itself is likely to take inordinate amounts of time.
+
+@item -Wpointer-sign @r{(C and Objective-C only)}
+@opindex Wpointer-sign
+@opindex Wno-pointer-sign
+Warn for pointer argument passing or assignment with different signedness.
+This option is only supported for C and Objective-C@.  It is implied by
+@option{-Wall} and by @option{-Wpedantic}, which can be disabled with
+@option{-Wno-pointer-sign}.
+
+@item -Wstack-protector
+@opindex Wstack-protector
+@opindex Wno-stack-protector
+This option is only active when @option{-fstack-protector} is active.  It
+warns about functions that are not protected against stack smashing.
+
+@item -Wno-mudflap
+@opindex Wno-mudflap
+Suppress warnings about constructs that cannot be instrumented by
+@option{-fmudflap}.
+
+@item -Woverlength-strings
+@opindex Woverlength-strings
+@opindex Wno-overlength-strings
+Warn about string constants that are longer than the ``minimum
+maximum'' length specified in the C standard.  Modern compilers
+generally allow string constants that are much longer than the
+standard's minimum limit, but very portable programs should avoid
+using longer strings.
+
+The limit applies @emph{after} string constant concatenation, and does
+not count the trailing NUL@.  In C90, the limit was 509 characters; in
+C99, it was raised to 4095.  C++98 does not specify a normative
+minimum maximum, so we do not diagnose overlength strings in C++@.
+
+This option is implied by @option{-Wpedantic}, and can be disabled with
+@option{-Wno-overlength-strings}.
+
+@item -Wunsuffixed-float-constants @r{(C and Objective-C only)}
+@opindex Wunsuffixed-float-constants
+
+Issue a warning for any floating constant that does not have
+a suffix.  When used together with @option{-Wsystem-headers} it
+warns about such constants in system header files.  This can be useful
+when preparing code to use with the @code{FLOAT_CONST_DECIMAL64} pragma
+from the decimal floating-point extension to C99.
+@end table
+
+@node Debugging Options
+@section Options for Debugging Your Program or GCC
+@cindex options, debugging
+@cindex debugging information options
+
+GCC has various special options that are used for debugging
+either your program or GCC:
+
+@table @gcctabopt
+@item -g
+@opindex g
+Produce debugging information in the operating system's native format
+(stabs, COFF, XCOFF, or DWARF 2)@.  GDB can work with this debugging
+information.
+
+On most systems that use stabs format, @option{-g} enables use of extra
+debugging information that only GDB can use; this extra information
+makes debugging work better in GDB but probably makes other debuggers
+crash or
+refuse to read the program.  If you want to control for certain whether
+to generate the extra information, use @option{-gstabs+}, @option{-gstabs},
+@option{-gxcoff+}, @option{-gxcoff}, or @option{-gvms} (see below).
+
+GCC allows you to use @option{-g} with
+@option{-O}.  The shortcuts taken by optimized code may occasionally
+produce surprising results: some variables you declared may not exist
+at all; flow of control may briefly move where you did not expect it;
+some statements may not be executed because they compute constant
+results or their values are already at hand; some statements may
+execute in different places because they have been moved out of loops.
+
+Nevertheless it proves possible to debug optimized output.  This makes
+it reasonable to use the optimizer for programs that might have bugs.
+
+The following options are useful when GCC is generated with the
+capability for more than one debugging format.
+
+@item -gsplit-dwarf
+@opindex gsplit-dwarf
+Separate as much dwarf debugging information as possible into a
+separate output file with the extension .dwo.  This option allows
+the build system to avoid linking files with debug information.  To
+be useful, this option requires a debugger capable of reading .dwo
+files.
+
+@item -ggdb
+@opindex ggdb
+Produce debugging information for use by GDB@.  This means to use the
+most expressive format available (DWARF 2, stabs, or the native format
+if neither of those are supported), including GDB extensions if at all
+possible.
+
+@item -gpubnames
+@opindex gpubnames
+Generate dwarf .debug_pubnames and .debug_pubtypes sections.
+
+@item -gstabs
+@opindex gstabs
+Produce debugging information in stabs format (if that is supported),
+without GDB extensions.  This is the format used by DBX on most BSD
+systems.  On MIPS, Alpha and System V Release 4 systems this option
+produces stabs debugging output that is not understood by DBX or SDB@.
+On System V Release 4 systems this option requires the GNU assembler.
+
+@item -feliminate-unused-debug-symbols
+@opindex feliminate-unused-debug-symbols
+Produce debugging information in stabs format (if that is supported),
+for only symbols that are actually used.
+
+@item -femit-class-debug-always
+Instead of emitting debugging information for a C++ class in only one
+object file, emit it in all object files using the class.  This option
+should be used only with debuggers that are unable to handle the way GCC
+normally emits debugging information for classes because using this
+option increases the size of debugging information by as much as a
+factor of two.
+
+@item -fdebug-types-section
+@opindex fdebug-types-section
+@opindex fno-debug-types-section
+When using DWARF Version 4 or higher, type DIEs can be put into
+their own @code{.debug_types} section instead of making them part of the
+@code{.debug_info} section.  It is more efficient to put them in a separate
+comdat sections since the linker can then remove duplicates.
+But not all DWARF consumers support @code{.debug_types} sections yet
+and on some objects @code{.debug_types} produces larger instead of smaller
+debugging information.
+
+@item -gstabs+
+@opindex gstabs+
+Produce debugging information in stabs format (if that is supported),
+using GNU extensions understood only by the GNU debugger (GDB)@.  The
+use of these extensions is likely to make other debuggers crash or
+refuse to read the program.
+
+@item -gcoff
+@opindex gcoff
+Produce debugging information in COFF format (if that is supported).
+This is the format used by SDB on most System V systems prior to
+System V Release 4.
+
+@item -gxcoff
+@opindex gxcoff
+Produce debugging information in XCOFF format (if that is supported).
+This is the format used by the DBX debugger on IBM RS/6000 systems.
+
+@item -gxcoff+
+@opindex gxcoff+
+Produce debugging information in XCOFF format (if that is supported),
+using GNU extensions understood only by the GNU debugger (GDB)@.  The
+use of these extensions is likely to make other debuggers crash or
+refuse to read the program, and may cause assemblers other than the GNU
+assembler (GAS) to fail with an error.
+
+@item -gdwarf-@var{version}
+@opindex gdwarf-@var{version}
+Produce debugging information in DWARF format (if that is supported).
+The value of @var{version} may be either 2, 3 or 4; the default version
+for most targets is 4.
+
+Note that with DWARF Version 2, some ports require and always
+use some non-conflicting DWARF 3 extensions in the unwind tables.
+
+Version 4 may require GDB 7.0 and @option{-fvar-tracking-assignments}
+for maximum benefit.
+
+@item -grecord-gcc-switches
+@opindex grecord-gcc-switches
+This switch causes the command-line options used to invoke the
+compiler that may affect code generation to be appended to the
+DW_AT_producer attribute in DWARF debugging information.  The options
+are concatenated with spaces separating them from each other and from
+the compiler version.  See also @option{-frecord-gcc-switches} for another
+way of storing compiler options into the object file.  This is the default.
+
+@item -gno-record-gcc-switches
+@opindex gno-record-gcc-switches
+Disallow appending command-line options to the DW_AT_producer attribute
+in DWARF debugging information.
+
+@item -gstrict-dwarf
+@opindex gstrict-dwarf
+Disallow using extensions of later DWARF standard version than selected
+with @option{-gdwarf-@var{version}}.  On most targets using non-conflicting
+DWARF extensions from later standard versions is allowed.
+
+@item -gno-strict-dwarf
+@opindex gno-strict-dwarf
+Allow using extensions of later DWARF standard version than selected with
+@option{-gdwarf-@var{version}}.
+
+@item -gvms
+@opindex gvms
+Produce debugging information in Alpha/VMS debug format (if that is
+supported).  This is the format used by DEBUG on Alpha/VMS systems.
+
+@item -g@var{level}
+@itemx -ggdb@var{level}
+@itemx -gstabs@var{level}
+@itemx -gcoff@var{level}
+@itemx -gxcoff@var{level}
+@itemx -gvms@var{level}
+Request debugging information and also use @var{level} to specify how
+much information.  The default level is 2.
+
+Level 0 produces no debug information at all.  Thus, @option{-g0} negates
+@option{-g}.
+
+Level 1 produces minimal information, enough for making backtraces in
+parts of the program that you don't plan to debug.  This includes
+descriptions of functions and external variables, but no information
+about local variables and no line numbers.
+
+Level 3 includes extra information, such as all the macro definitions
+present in the program.  Some debuggers support macro expansion when
+you use @option{-g3}.
+
+@option{-gdwarf-2} does not accept a concatenated debug level, because
+GCC used to support an option @option{-gdwarf} that meant to generate
+debug information in version 1 of the DWARF format (which is very
+different from version 2), and it would have been too confusing.  That
+debug format is long obsolete, but the option cannot be changed now.
+Instead use an additional @option{-g@var{level}} option to change the
+debug level for DWARF.
+
+@item -gtoggle
+@opindex gtoggle
+Turn off generation of debug info, if leaving out this option
+generates it, or turn it on at level 2 otherwise.  The position of this
+argument in the command line does not matter; it takes effect after all
+other options are processed, and it does so only once, no matter how
+many times it is given.  This is mainly intended to be used with
+@option{-fcompare-debug}.
+
+@item -fsanitize=address
+Enable AddressSanitizer, a fast memory error detector.
+Memory access instructions will be instrumented to detect
+out-of-bounds and use-after-free bugs.
+See @uref{http://code.google.com/p/address-sanitizer/} for more details.
+
+@item -fsanitize=thread
+Enable ThreadSanitizer, a fast data race detector.
+Memory access instructions will be instrumented to detect
+data race bugs.
+See @uref{http://code.google.com/p/data-race-test/wiki/ThreadSanitizer} for more details.
+
+@item -fdump-final-insns@r{[}=@var{file}@r{]}
+@opindex fdump-final-insns
+Dump the final internal representation (RTL) to @var{file}.  If the
+optional argument is omitted (or if @var{file} is @code{.}), the name
+of the dump file is determined by appending @code{.gkd} to the
+compilation output file name.
+
+@item -fcompare-debug@r{[}=@var{opts}@r{]}
+@opindex fcompare-debug
+@opindex fno-compare-debug
+If no error occurs during compilation, run the compiler a second time,
+adding @var{opts} and @option{-fcompare-debug-second} to the arguments
+passed to the second compilation.  Dump the final internal
+representation in both compilations, and print an error if they differ.
+
+If the equal sign is omitted, the default @option{-gtoggle} is used.
+
+The environment variable @env{GCC_COMPARE_DEBUG}, if defined, non-empty
+and nonzero, implicitly enables @option{-fcompare-debug}.  If
+@env{GCC_COMPARE_DEBUG} is defined to a string starting with a dash,
+then it is used for @var{opts}, otherwise the default @option{-gtoggle}
+is used.
+
+@option{-fcompare-debug=}, with the equal sign but without @var{opts},
+is equivalent to @option{-fno-compare-debug}, which disables the dumping
+of the final representation and the second compilation, preventing even
+@env{GCC_COMPARE_DEBUG} from taking effect.
+
+To verify full coverage during @option{-fcompare-debug} testing, set
+@env{GCC_COMPARE_DEBUG} to say @samp{-fcompare-debug-not-overridden},
+which GCC rejects as an invalid option in any actual compilation
+(rather than preprocessing, assembly or linking).  To get just a
+warning, setting @env{GCC_COMPARE_DEBUG} to @samp{-w%n-fcompare-debug
+not overridden} will do.
+
+@item -fcompare-debug-second
+@opindex fcompare-debug-second
+This option is implicitly passed to the compiler for the second
+compilation requested by @option{-fcompare-debug}, along with options to
+silence warnings, and omitting other options that would cause
+side-effect compiler outputs to files or to the standard output.  Dump
+files and preserved temporary files are renamed so as to contain the
+@code{.gk} additional extension during the second compilation, to avoid
+overwriting those generated by the first.
+
+When this option is passed to the compiler driver, it causes the
+@emph{first} compilation to be skipped, which makes it useful for little
+other than debugging the compiler proper.
+
+@item -feliminate-dwarf2-dups
+@opindex feliminate-dwarf2-dups
+Compress DWARF 2 debugging information by eliminating duplicated
+information about each symbol.  This option only makes sense when
+generating DWARF 2 debugging information with @option{-gdwarf-2}.
+
+@item -femit-struct-debug-baseonly
+Emit debug information for struct-like types
+only when the base name of the compilation source file
+matches the base name of file in which the struct is defined.
+
+This option substantially reduces the size of debugging information,
+but at significant potential loss in type information to the debugger.
+See @option{-femit-struct-debug-reduced} for a less aggressive option.
+See @option{-femit-struct-debug-detailed} for more detailed control.
+
+This option works only with DWARF 2.
+
+@item -femit-struct-debug-reduced
+Emit debug information for struct-like types
+only when the base name of the compilation source file
+matches the base name of file in which the type is defined,
+unless the struct is a template or defined in a system header.
+
+This option significantly reduces the size of debugging information,
+with some potential loss in type information to the debugger.
+See @option{-femit-struct-debug-baseonly} for a more aggressive option.
+See @option{-femit-struct-debug-detailed} for more detailed control.
+
+This option works only with DWARF 2.
+
+@item -femit-struct-debug-detailed@r{[}=@var{spec-list}@r{]}
+Specify the struct-like types
+for which the compiler generates debug information.
+The intent is to reduce duplicate struct debug information
+between different object files within the same program.
+
+This option is a detailed version of
+@option{-femit-struct-debug-reduced} and @option{-femit-struct-debug-baseonly},
+which serves for most needs.
+
+A specification has the syntax@*
+[@samp{dir:}|@samp{ind:}][@samp{ord:}|@samp{gen:}](@samp{any}|@samp{sys}|@samp{base}|@samp{none})
+
+The optional first word limits the specification to
+structs that are used directly (@samp{dir:}) or used indirectly (@samp{ind:}).
+A struct type is used directly when it is the type of a variable, member.
+Indirect uses arise through pointers to structs.
+That is, when use of an incomplete struct is valid, the use is indirect.
+An example is
+@samp{struct one direct; struct two * indirect;}.
+
+The optional second word limits the specification to
+ordinary structs (@samp{ord:}) or generic structs (@samp{gen:}).
+Generic structs are a bit complicated to explain.
+For C++, these are non-explicit specializations of template classes,
+or non-template classes within the above.
+Other programming languages have generics,
+but @option{-femit-struct-debug-detailed} does not yet implement them.
+
+The third word specifies the source files for those
+structs for which the compiler should emit debug information.
+The values @samp{none} and @samp{any} have the normal meaning.
+The value @samp{base} means that
+the base of name of the file in which the type declaration appears
+must match the base of the name of the main compilation file.
+In practice, this means that when compiling @file{foo.c}, debug information
+is generated for types declared in that file and @file{foo.h},
+but not other header files.
+The value @samp{sys} means those types satisfying @samp{base}
+or declared in system or compiler headers.
+
+You may need to experiment to determine the best settings for your application.
+
+The default is @option{-femit-struct-debug-detailed=all}.
+
+This option works only with DWARF 2.
+
+@item -fno-merge-debug-strings
+@opindex fmerge-debug-strings
+@opindex fno-merge-debug-strings
+Direct the linker to not merge together strings in the debugging
+information that are identical in different object files.  Merging is
+not supported by all assemblers or linkers.  Merging decreases the size
+of the debug information in the output file at the cost of increasing
+link processing time.  Merging is enabled by default.
+
+@item -fdebug-prefix-map=@var{old}=@var{new}
+@opindex fdebug-prefix-map
+When compiling files in directory @file{@var{old}}, record debugging
+information describing them as in @file{@var{new}} instead.
+
+@item -fno-dwarf2-cfi-asm
+@opindex fdwarf2-cfi-asm
+@opindex fno-dwarf2-cfi-asm
+Emit DWARF 2 unwind info as compiler generated @code{.eh_frame} section
+instead of using GAS @code{.cfi_*} directives.
+
+@cindex @command{prof}
+@item -p
+@opindex p
+Generate extra code to write profile information suitable for the
+analysis program @command{prof}.  You must use this option when compiling
+the source files you want data about, and you must also use it when
+linking.
+
+@cindex @command{gprof}
+@item -pg
+@opindex pg
+Generate extra code to write profile information suitable for the
+analysis program @command{gprof}.  You must use this option when compiling
+the source files you want data about, and you must also use it when
+linking.
+
+@item -Q
+@opindex Q
+Makes the compiler print out each function name as it is compiled, and
+print some statistics about each pass when it finishes.
+
+@item -ftime-report
+@opindex ftime-report
+Makes the compiler print some statistics about the time consumed by each
+pass when it finishes.
+
+@item -fmem-report
+@opindex fmem-report
+Makes the compiler print some statistics about permanent memory
+allocation when it finishes.
+
+@item -fmem-report-wpa
+@opindex fmem-report-wpa
+Makes the compiler print some statistics about permanent memory
+allocation for the WPA phase only.
+
+@item -fpre-ipa-mem-report
+@opindex fpre-ipa-mem-report
+@item -fpost-ipa-mem-report
+@opindex fpost-ipa-mem-report
+Makes the compiler print some statistics about permanent memory
+allocation before or after interprocedural optimization.
+
+@item -fprofile-report
+@opindex fprofile-report
+Makes the compiler print some statistics about consistency of the
+(estimated) profile and effect of individual passes.
+
+@item -fstack-usage
+@opindex fstack-usage
+Makes the compiler output stack usage information for the program, on a
+per-function basis.  The filename for the dump is made by appending
+@file{.su} to the @var{auxname}.  @var{auxname} is generated from the name of
+the output file, if explicitly specified and it is not an executable,
+otherwise it is the basename of the source file.  An entry is made up
+of three fields:
+
+@itemize
+@item
+The name of the function.
+@item
+A number of bytes.
+@item
+One or more qualifiers: @code{static}, @code{dynamic}, @code{bounded}.
+@end itemize
+
+The qualifier @code{static} means that the function manipulates the stack
+statically: a fixed number of bytes are allocated for the frame on function
+entry and released on function exit; no stack adjustments are otherwise made
+in the function.  The second field is this fixed number of bytes.
+
+The qualifier @code{dynamic} means that the function manipulates the stack
+dynamically: in addition to the static allocation described above, stack
+adjustments are made in the body of the function, for example to push/pop
+arguments around function calls.  If the qualifier @code{bounded} is also
+present, the amount of these adjustments is bounded at compile time and
+the second field is an upper bound of the total amount of stack used by
+the function.  If it is not present, the amount of these adjustments is
+not bounded at compile time and the second field only represents the
+bounded part.
+
+@item -fprofile-arcs
+@opindex fprofile-arcs
+Add code so that program flow @dfn{arcs} are instrumented.  During
+execution the program records how many times each branch and call is
+executed and how many times it is taken or returns.  When the compiled
+program exits it saves this data to a file called
+@file{@var{auxname}.gcda} for each source file.  The data may be used for
+profile-directed optimizations (@option{-fbranch-probabilities}), or for
+test coverage analysis (@option{-ftest-coverage}).  Each object file's
+@var{auxname} is generated from the name of the output file, if
+explicitly specified and it is not the final executable, otherwise it is
+the basename of the source file.  In both cases any suffix is removed
+(e.g.@: @file{foo.gcda} for input file @file{dir/foo.c}, or
+@file{dir/foo.gcda} for output file specified as @option{-o dir/foo.o}).
+@xref{Cross-profiling}.
+
+@cindex @command{gcov}
+@item --coverage
+@opindex coverage
+
+This option is used to compile and link code instrumented for coverage
+analysis.  The option is a synonym for @option{-fprofile-arcs}
+@option{-ftest-coverage} (when compiling) and @option{-lgcov} (when
+linking).  See the documentation for those options for more details.
+
+@itemize
+
+@item
+Compile the source files with @option{-fprofile-arcs} plus optimization
+and code generation options.  For test coverage analysis, use the
+additional @option{-ftest-coverage} option.  You do not need to profile
+every source file in a program.
+
+@item
+Link your object files with @option{-lgcov} or @option{-fprofile-arcs}
+(the latter implies the former).
+
+@item
+Run the program on a representative workload to generate the arc profile
+information.  This may be repeated any number of times.  You can run
+concurrent instances of your program, and provided that the file system
+supports locking, the data files will be correctly updated.  Also
+@code{fork} calls are detected and correctly handled (double counting
+will not happen).
+
+@item
+For profile-directed optimizations, compile the source files again with
+the same optimization and code generation options plus
+@option{-fbranch-probabilities} (@pxref{Optimize Options,,Options that
+Control Optimization}).
+
+@item
+For test coverage analysis, use @command{gcov} to produce human readable
+information from the @file{.gcno} and @file{.gcda} files.  Refer to the
+@command{gcov} documentation for further information.
+
+@end itemize
+
+With @option{-fprofile-arcs}, for each function of your program GCC
+creates a program flow graph, then finds a spanning tree for the graph.
+Only arcs that are not on the spanning tree have to be instrumented: the
+compiler adds code to count the number of times that these arcs are
+executed.  When an arc is the only exit or only entrance to a block, the
+instrumentation code can be added to the block; otherwise, a new basic
+block must be created to hold the instrumentation code.
+
+@need 2000
+@item -ftest-coverage
+@opindex ftest-coverage
+Produce a notes file that the @command{gcov} code-coverage utility
+(@pxref{Gcov,, @command{gcov}---a Test Coverage Program}) can use to
+show program coverage.  Each source file's note file is called
+@file{@var{auxname}.gcno}.  Refer to the @option{-fprofile-arcs} option
+above for a description of @var{auxname} and instructions on how to
+generate test coverage data.  Coverage data matches the source files
+more closely if you do not optimize.
+
+@item -fdbg-cnt-list
+@opindex fdbg-cnt-list
+Print the name and the counter upper bound for all debug counters.
+
+
+@item -fdbg-cnt=@var{counter-value-list}
+@opindex fdbg-cnt
+Set the internal debug counter upper bound.  @var{counter-value-list}
+is a comma-separated list of @var{name}:@var{value} pairs
+which sets the upper bound of each debug counter @var{name} to @var{value}.
+All debug counters have the initial upper bound of @code{UINT_MAX};
+thus @code{dbg_cnt()} returns true always unless the upper bound
+is set by this option.
+For example, with @option{-fdbg-cnt=dce:10,tail_call:0},
+@code{dbg_cnt(dce)} returns true only for first 10 invocations.
+
+@item -fenable-@var{kind}-@var{pass}
+@itemx -fdisable-@var{kind}-@var{pass}=@var{range-list}
+@opindex fdisable-
+@opindex fenable-
+
+This is a set of options that are used to explicitly disable/enable
+optimization passes.  These options are intended for use for debugging GCC.
+Compiler users should use regular options for enabling/disabling
+passes instead.
+
+@table @gcctabopt
+
+@item -fdisable-ipa-@var{pass}
+Disable IPA pass @var{pass}. @var{pass} is the pass name.  If the same pass is
+statically invoked in the compiler multiple times, the pass name should be
+appended with a sequential number starting from 1.
+
+@item -fdisable-rtl-@var{pass}
+@itemx -fdisable-rtl-@var{pass}=@var{range-list}
+Disable RTL pass @var{pass}.  @var{pass} is the pass name.  If the same pass is
+statically invoked in the compiler multiple times, the pass name should be
+appended with a sequential number starting from 1.  @var{range-list} is a 
+comma-separated list of function ranges or assembler names.  Each range is a number
+pair separated by a colon.  The range is inclusive in both ends.  If the range
+is trivial, the number pair can be simplified as a single number.  If the
+function's call graph node's @var{uid} falls within one of the specified ranges,
+the @var{pass} is disabled for that function.  The @var{uid} is shown in the
+function header of a dump file, and the pass names can be dumped by using
+option @option{-fdump-passes}.
+
+@item -fdisable-tree-@var{pass}
+@itemx -fdisable-tree-@var{pass}=@var{range-list}
+Disable tree pass @var{pass}.  See @option{-fdisable-rtl} for the description of
+option arguments.
+
+@item -fenable-ipa-@var{pass}
+Enable IPA pass @var{pass}.  @var{pass} is the pass name.  If the same pass is
+statically invoked in the compiler multiple times, the pass name should be
+appended with a sequential number starting from 1.
+
+@item -fenable-rtl-@var{pass}
+@itemx -fenable-rtl-@var{pass}=@var{range-list}
+Enable RTL pass @var{pass}.  See @option{-fdisable-rtl} for option argument
+description and examples.
+
+@item -fenable-tree-@var{pass}
+@itemx -fenable-tree-@var{pass}=@var{range-list}
+Enable tree pass @var{pass}.  See @option{-fdisable-rtl} for the description
+of option arguments.
+
+@end table
+
+Here are some examples showing uses of these options.
+
+@smallexample
+
+# disable ccp1 for all functions
+   -fdisable-tree-ccp1
+# disable complete unroll for function whose cgraph node uid is 1
+   -fenable-tree-cunroll=1
+# disable gcse2 for functions at the following ranges [1,1],
+# [300,400], and [400,1000]
+# disable gcse2 for functions foo and foo2
+   -fdisable-rtl-gcse2=foo,foo2
+# disable early inlining
+   -fdisable-tree-einline
+# disable ipa inlining
+   -fdisable-ipa-inline
+# enable tree full unroll
+   -fenable-tree-unroll
+
+@end smallexample
+
+@item -d@var{letters}
+@itemx -fdump-rtl-@var{pass}
+@itemx -fdump-rtl-@var{pass}=@var{filename}
+@opindex d
+Says to make debugging dumps during compilation at times specified by
+@var{letters}.  This is used for debugging the RTL-based passes of the
+compiler.  The file names for most of the dumps are made by appending
+a pass number and a word to the @var{dumpname}, and the files are
+created in the directory of the output file. In case of
+@option{=@var{filename}} option, the dump is output on the given file
+instead of the pass numbered dump files. Note that the pass number is
+computed statically as passes get registered into the pass manager.
+Thus the numbering is not related to the dynamic order of execution of
+passes.  In particular, a pass installed by a plugin could have a
+number over 200 even if it executed quite early.  @var{dumpname} is
+generated from the name of the output file, if explicitly specified
+and it is not an executable, otherwise it is the basename of the
+source file. These switches may have different effects when
+@option{-E} is used for preprocessing.
+
+Debug dumps can be enabled with a @option{-fdump-rtl} switch or some
+@option{-d} option @var{letters}.  Here are the possible
+letters for use in @var{pass} and @var{letters}, and their meanings:
+
+@table @gcctabopt
+
+@item -fdump-rtl-alignments
+@opindex fdump-rtl-alignments
+Dump after branch alignments have been computed.
+
+@item -fdump-rtl-asmcons
+@opindex fdump-rtl-asmcons
+Dump after fixing rtl statements that have unsatisfied in/out constraints.
+
+@item -fdump-rtl-auto_inc_dec
+@opindex fdump-rtl-auto_inc_dec
+Dump after auto-inc-dec discovery.  This pass is only run on
+architectures that have auto inc or auto dec instructions.
+
+@item -fdump-rtl-barriers
+@opindex fdump-rtl-barriers
+Dump after cleaning up the barrier instructions.
+
+@item -fdump-rtl-bbpart
+@opindex fdump-rtl-bbpart
+Dump after partitioning hot and cold basic blocks.
+
+@item -fdump-rtl-bbro
+@opindex fdump-rtl-bbro
+Dump after block reordering.
+
+@item -fdump-rtl-btl1
+@itemx -fdump-rtl-btl2
+@opindex fdump-rtl-btl2
+@opindex fdump-rtl-btl2
+@option{-fdump-rtl-btl1} and @option{-fdump-rtl-btl2} enable dumping
+after the two branch
+target load optimization passes.
+
+@item -fdump-rtl-bypass
+@opindex fdump-rtl-bypass
+Dump after jump bypassing and control flow optimizations.
+
+@item -fdump-rtl-combine
+@opindex fdump-rtl-combine
+Dump after the RTL instruction combination pass.
+
+@item -fdump-rtl-compgotos
+@opindex fdump-rtl-compgotos
+Dump after duplicating the computed gotos.
+
+@item -fdump-rtl-ce1
+@itemx -fdump-rtl-ce2
+@itemx -fdump-rtl-ce3
+@opindex fdump-rtl-ce1
+@opindex fdump-rtl-ce2
+@opindex fdump-rtl-ce3
+@option{-fdump-rtl-ce1}, @option{-fdump-rtl-ce2}, and
+@option{-fdump-rtl-ce3} enable dumping after the three
+if conversion passes.
+
+@item -fdump-rtl-cprop_hardreg
+@opindex fdump-rtl-cprop_hardreg
+Dump after hard register copy propagation.
+
+@item -fdump-rtl-csa
+@opindex fdump-rtl-csa
+Dump after combining stack adjustments.
+
+@item -fdump-rtl-cse1
+@itemx -fdump-rtl-cse2
+@opindex fdump-rtl-cse1
+@opindex fdump-rtl-cse2
+@option{-fdump-rtl-cse1} and @option{-fdump-rtl-cse2} enable dumping after
+the two common subexpression elimination passes.
+
+@item -fdump-rtl-dce
+@opindex fdump-rtl-dce
+Dump after the standalone dead code elimination passes.
+
+@item -fdump-rtl-dbr
+@opindex fdump-rtl-dbr
+Dump after delayed branch scheduling.
+
+@item -fdump-rtl-dce1
+@itemx -fdump-rtl-dce2
+@opindex fdump-rtl-dce1
+@opindex fdump-rtl-dce2
+@option{-fdump-rtl-dce1} and @option{-fdump-rtl-dce2} enable dumping after
+the two dead store elimination passes.
+
+@item -fdump-rtl-eh
+@opindex fdump-rtl-eh
+Dump after finalization of EH handling code.
+
+@item -fdump-rtl-eh_ranges
+@opindex fdump-rtl-eh_ranges
+Dump after conversion of EH handling range regions.
+
+@item -fdump-rtl-expand
+@opindex fdump-rtl-expand
+Dump after RTL generation.
+
+@item -fdump-rtl-fwprop1
+@itemx -fdump-rtl-fwprop2
+@opindex fdump-rtl-fwprop1
+@opindex fdump-rtl-fwprop2
+@option{-fdump-rtl-fwprop1} and @option{-fdump-rtl-fwprop2} enable
+dumping after the two forward propagation passes.
+
+@item -fdump-rtl-gcse1
+@itemx -fdump-rtl-gcse2
+@opindex fdump-rtl-gcse1
+@opindex fdump-rtl-gcse2
+@option{-fdump-rtl-gcse1} and @option{-fdump-rtl-gcse2} enable dumping
+after global common subexpression elimination.
+
+@item -fdump-rtl-init-regs
+@opindex fdump-rtl-init-regs
+Dump after the initialization of the registers.
+
+@item -fdump-rtl-initvals
+@opindex fdump-rtl-initvals
+Dump after the computation of the initial value sets.
+
+@item -fdump-rtl-into_cfglayout
+@opindex fdump-rtl-into_cfglayout
+Dump after converting to cfglayout mode.
+
+@item -fdump-rtl-ira
+@opindex fdump-rtl-ira
+Dump after iterated register allocation.
+
+@item -fdump-rtl-jump
+@opindex fdump-rtl-jump
+Dump after the second jump optimization.
+
+@item -fdump-rtl-loop2
+@opindex fdump-rtl-loop2
+@option{-fdump-rtl-loop2} enables dumping after the rtl
+loop optimization passes.
+
+@item -fdump-rtl-mach
+@opindex fdump-rtl-mach
+Dump after performing the machine dependent reorganization pass, if that
+pass exists.
+
+@item -fdump-rtl-mode_sw
+@opindex fdump-rtl-mode_sw
+Dump after removing redundant mode switches.
+
+@item -fdump-rtl-rnreg
+@opindex fdump-rtl-rnreg
+Dump after register renumbering.
+
+@item -fdump-rtl-outof_cfglayout
+@opindex fdump-rtl-outof_cfglayout
+Dump after converting from cfglayout mode.
+
+@item -fdump-rtl-peephole2
+@opindex fdump-rtl-peephole2
+Dump after the peephole pass.
+
+@item -fdump-rtl-postreload
+@opindex fdump-rtl-postreload
+Dump after post-reload optimizations.
+
+@item -fdump-rtl-pro_and_epilogue
+@opindex fdump-rtl-pro_and_epilogue
+Dump after generating the function prologues and epilogues.
+
+@item -fdump-rtl-regmove
+@opindex fdump-rtl-regmove
+Dump after the register move pass.
+
+@item -fdump-rtl-sched1
+@itemx -fdump-rtl-sched2
+@opindex fdump-rtl-sched1
+@opindex fdump-rtl-sched2
+@option{-fdump-rtl-sched1} and @option{-fdump-rtl-sched2} enable dumping
+after the basic block scheduling passes.
+
+@item -fdump-rtl-see
+@opindex fdump-rtl-see
+Dump after sign extension elimination.
+
+@item -fdump-rtl-seqabstr
+@opindex fdump-rtl-seqabstr
+Dump after common sequence discovery.
+
+@item -fdump-rtl-shorten
+@opindex fdump-rtl-shorten
+Dump after shortening branches.
+
+@item -fdump-rtl-sibling
+@opindex fdump-rtl-sibling
+Dump after sibling call optimizations.
+
+@item -fdump-rtl-split1
+@itemx -fdump-rtl-split2
+@itemx -fdump-rtl-split3
+@itemx -fdump-rtl-split4
+@itemx -fdump-rtl-split5
+@opindex fdump-rtl-split1
+@opindex fdump-rtl-split2
+@opindex fdump-rtl-split3
+@opindex fdump-rtl-split4
+@opindex fdump-rtl-split5
+@option{-fdump-rtl-split1}, @option{-fdump-rtl-split2},
+@option{-fdump-rtl-split3}, @option{-fdump-rtl-split4} and
+@option{-fdump-rtl-split5} enable dumping after five rounds of
+instruction splitting.
+
+@item -fdump-rtl-sms
+@opindex fdump-rtl-sms
+Dump after modulo scheduling.  This pass is only run on some
+architectures.
+
+@item -fdump-rtl-stack
+@opindex fdump-rtl-stack
+Dump after conversion from GCC's ``flat register file'' registers to the
+x87's stack-like registers.  This pass is only run on x86 variants.
+
+@item -fdump-rtl-subreg1
+@itemx -fdump-rtl-subreg2
+@opindex fdump-rtl-subreg1
+@opindex fdump-rtl-subreg2
+@option{-fdump-rtl-subreg1} and @option{-fdump-rtl-subreg2} enable dumping after
+the two subreg expansion passes.
+
+@item -fdump-rtl-unshare
+@opindex fdump-rtl-unshare
+Dump after all rtl has been unshared.
+
+@item -fdump-rtl-vartrack
+@opindex fdump-rtl-vartrack
+Dump after variable tracking.
+
+@item -fdump-rtl-vregs
+@opindex fdump-rtl-vregs
+Dump after converting virtual registers to hard registers.
+
+@item -fdump-rtl-web
+@opindex fdump-rtl-web
+Dump after live range splitting.
+
+@item -fdump-rtl-regclass
+@itemx -fdump-rtl-subregs_of_mode_init
+@itemx -fdump-rtl-subregs_of_mode_finish
+@itemx -fdump-rtl-dfinit
+@itemx -fdump-rtl-dfinish
+@opindex fdump-rtl-regclass
+@opindex fdump-rtl-subregs_of_mode_init
+@opindex fdump-rtl-subregs_of_mode_finish
+@opindex fdump-rtl-dfinit
+@opindex fdump-rtl-dfinish
+These dumps are defined but always produce empty files.
+
+@item -da
+@itemx -fdump-rtl-all
+@opindex da
+@opindex fdump-rtl-all
+Produce all the dumps listed above.
+
+@item -dA
+@opindex dA
+Annotate the assembler output with miscellaneous debugging information.
+
+@item -dD
+@opindex dD
+Dump all macro definitions, at the end of preprocessing, in addition to
+normal output.
+
+@item -dH
+@opindex dH
+Produce a core dump whenever an error occurs.
+
+@item -dp
+@opindex dp
+Annotate the assembler output with a comment indicating which
+pattern and alternative is used.  The length of each instruction is
+also printed.
+
+@item -dP
+@opindex dP
+Dump the RTL in the assembler output as a comment before each instruction.
+Also turns on @option{-dp} annotation.
+
+@item -dx
+@opindex dx
+Just generate RTL for a function instead of compiling it.  Usually used
+with @option{-fdump-rtl-expand}.
+@end table
+
+@item -fdump-noaddr
+@opindex fdump-noaddr
+When doing debugging dumps, suppress address output.  This makes it more
+feasible to use diff on debugging dumps for compiler invocations with
+different compiler binaries and/or different
+text / bss / data / heap / stack / dso start locations.
+
+@item -fdump-unnumbered
+@opindex fdump-unnumbered
+When doing debugging dumps, suppress instruction numbers and address output.
+This makes it more feasible to use diff on debugging dumps for compiler
+invocations with different options, in particular with and without
+@option{-g}.
+
+@item -fdump-unnumbered-links
+@opindex fdump-unnumbered-links
+When doing debugging dumps (see @option{-d} option above), suppress
+instruction numbers for the links to the previous and next instructions
+in a sequence.
+
+@item -fdump-translation-unit @r{(C++ only)}
+@itemx -fdump-translation-unit-@var{options} @r{(C++ only)}
+@opindex fdump-translation-unit
+Dump a representation of the tree structure for the entire translation
+unit to a file.  The file name is made by appending @file{.tu} to the
+source file name, and the file is created in the same directory as the
+output file.  If the @samp{-@var{options}} form is used, @var{options}
+controls the details of the dump as described for the
+@option{-fdump-tree} options.
+
+@item -fdump-class-hierarchy @r{(C++ only)}
+@itemx -fdump-class-hierarchy-@var{options} @r{(C++ only)}
+@opindex fdump-class-hierarchy
+Dump a representation of each class's hierarchy and virtual function
+table layout to a file.  The file name is made by appending
+@file{.class} to the source file name, and the file is created in the
+same directory as the output file.  If the @samp{-@var{options}} form
+is used, @var{options} controls the details of the dump as described
+for the @option{-fdump-tree} options.
+
+@item -fdump-ipa-@var{switch}
+@opindex fdump-ipa
+Control the dumping at various stages of inter-procedural analysis
+language tree to a file.  The file name is generated by appending a
+switch specific suffix to the source file name, and the file is created
+in the same directory as the output file.  The following dumps are
+possible:
+
+@table @samp
+@item all
+Enables all inter-procedural analysis dumps.
+
+@item cgraph
+Dumps information about call-graph optimization, unused function removal,
+and inlining decisions.
+
+@item inline
+Dump after function inlining.
+
+@end table
+
+@item -fdump-passes
+@opindex fdump-passes
+Dump the list of optimization passes that are turned on and off by
+the current command-line options.
+
+@item -fdump-statistics-@var{option}
+@opindex fdump-statistics
+Enable and control dumping of pass statistics in a separate file.  The
+file name is generated by appending a suffix ending in
+@samp{.statistics} to the source file name, and the file is created in
+the same directory as the output file.  If the @samp{-@var{option}}
+form is used, @samp{-stats} causes counters to be summed over the
+whole compilation unit while @samp{-details} dumps every event as
+the passes generate them.  The default with no option is to sum
+counters for each function compiled.
+
+@item -fdump-tree-@var{switch}
+@itemx -fdump-tree-@var{switch}-@var{options}
+@itemx -fdump-tree-@var{switch}-@var{options}=@var{filename}
+@opindex fdump-tree
+Control the dumping at various stages of processing the intermediate
+language tree to a file.  The file name is generated by appending a
+switch-specific suffix to the source file name, and the file is
+created in the same directory as the output file. In case of
+@option{=@var{filename}} option, the dump is output on the given file
+instead of the auto named dump files.  If the @samp{-@var{options}}
+form is used, @var{options} is a list of @samp{-} separated options
+which control the details of the dump.  Not all options are applicable
+to all dumps; those that are not meaningful are ignored.  The
+following options are available
+
+@table @samp
+@item address
+Print the address of each node.  Usually this is not meaningful as it
+changes according to the environment and source file.  Its primary use
+is for tying up a dump file with a debug environment.
+@item asmname
+If @code{DECL_ASSEMBLER_NAME} has been set for a given decl, use that
+in the dump instead of @code{DECL_NAME}.  Its primary use is ease of
+use working backward from mangled names in the assembly file.
+@item slim
+When dumping front-end intermediate representations, inhibit dumping
+of members of a scope or body of a function merely because that scope
+has been reached.  Only dump such items when they are directly reachable
+by some other path.
+
+When dumping pretty-printed trees, this option inhibits dumping the
+bodies of control structures.
+
+When dumping RTL, print the RTL in slim (condensed) form instead of
+the default LISP-like representation.
+@item raw
+Print a raw representation of the tree.  By default, trees are
+pretty-printed into a C-like representation.
+@item details
+Enable more detailed dumps (not honored by every dump option). Also
+include information from the optimization passes.
+@item stats
+Enable dumping various statistics about the pass (not honored by every dump
+option).
+@item blocks
+Enable showing basic block boundaries (disabled in raw dumps).
+@item graph
+For each of the other indicated dump files (@option{-fdump-rtl-@var{pass}}),
+dump a representation of the control flow graph suitable for viewing with
+GraphViz to @file{@var{file}.@var{passid}.@var{pass}.dot}.  Each function in
+the file is pretty-printed as a subgraph, so that GraphViz can render them
+all in a single plot.
+
+This option currently only works for RTL dumps, and the RTL is always
+dumped in slim form.
+@item vops
+Enable showing virtual operands for every statement.
+@item lineno
+Enable showing line numbers for statements.
+@item uid
+Enable showing the unique ID (@code{DECL_UID}) for each variable.
+@item verbose
+Enable showing the tree dump for each statement.
+@item eh
+Enable showing the EH region number holding each statement.
+@item scev
+Enable showing scalar evolution analysis details.
+@item optimized
+Enable showing optimization information (only available in certain
+passes).
+@item missed
+Enable showing missed optimization information (only available in certain
+passes).
+@item notes
+Enable other detailed optimization information (only available in
+certain passes).
+@item =@var{filename}
+Instead of an auto named dump file, output into the given file
+name. The file names @file{stdout} and @file{stderr} are treated
+specially and are considered already open standard streams. For
+example,
+
+@smallexample
+gcc -O2 -ftree-vectorize -fdump-tree-vect-blocks=foo.dump
+     -fdump-tree-pre=stderr file.c
+@end smallexample
+
+outputs vectorizer dump into @file{foo.dump}, while the PRE dump is
+output on to @file{stderr}. If two conflicting dump filenames are
+given for the same pass, then the latter option overrides the earlier
+one.
+
+@item all
+Turn on all options, except @option{raw}, @option{slim}, @option{verbose}
+and @option{lineno}.
+
+@item optall
+Turn on all optimization options, i.e., @option{optimized},
+@option{missed}, and @option{note}.
+@end table
+
+The following tree dumps are possible:
+@table @samp
+
+@item original
+@opindex fdump-tree-original
+Dump before any tree based optimization, to @file{@var{file}.original}.
+
+@item optimized
+@opindex fdump-tree-optimized
+Dump after all tree based optimization, to @file{@var{file}.optimized}.
+
+@item gimple
+@opindex fdump-tree-gimple
+Dump each function before and after the gimplification pass to a file.  The
+file name is made by appending @file{.gimple} to the source file name.
+
+@item cfg
+@opindex fdump-tree-cfg
+Dump the control flow graph of each function to a file.  The file name is
+made by appending @file{.cfg} to the source file name.
+
+@item ch
+@opindex fdump-tree-ch
+Dump each function after copying loop headers.  The file name is made by
+appending @file{.ch} to the source file name.
+
+@item ssa
+@opindex fdump-tree-ssa
+Dump SSA related information to a file.  The file name is made by appending
+@file{.ssa} to the source file name.
+
+@item alias
+@opindex fdump-tree-alias
+Dump aliasing information for each function.  The file name is made by
+appending @file{.alias} to the source file name.
+
+@item ccp
+@opindex fdump-tree-ccp
+Dump each function after CCP@.  The file name is made by appending
+@file{.ccp} to the source file name.
+
+@item storeccp
+@opindex fdump-tree-storeccp
+Dump each function after STORE-CCP@.  The file name is made by appending
+@file{.storeccp} to the source file name.
+
+@item pre
+@opindex fdump-tree-pre
+Dump trees after partial redundancy elimination.  The file name is made
+by appending @file{.pre} to the source file name.
+
+@item fre
+@opindex fdump-tree-fre
+Dump trees after full redundancy elimination.  The file name is made
+by appending @file{.fre} to the source file name.
+
+@item copyprop
+@opindex fdump-tree-copyprop
+Dump trees after copy propagation.  The file name is made
+by appending @file{.copyprop} to the source file name.
+
+@item store_copyprop
+@opindex fdump-tree-store_copyprop
+Dump trees after store copy-propagation.  The file name is made
+by appending @file{.store_copyprop} to the source file name.
+
+@item dce
+@opindex fdump-tree-dce
+Dump each function after dead code elimination.  The file name is made by
+appending @file{.dce} to the source file name.
+
+@item mudflap
+@opindex fdump-tree-mudflap
+Dump each function after adding mudflap instrumentation.  The file name is
+made by appending @file{.mudflap} to the source file name.
+
+@item sra
+@opindex fdump-tree-sra
+Dump each function after performing scalar replacement of aggregates.  The
+file name is made by appending @file{.sra} to the source file name.
+
+@item sink
+@opindex fdump-tree-sink
+Dump each function after performing code sinking.  The file name is made
+by appending @file{.sink} to the source file name.
+
+@item dom
+@opindex fdump-tree-dom
+Dump each function after applying dominator tree optimizations.  The file
+name is made by appending @file{.dom} to the source file name.
+
+@item dse
+@opindex fdump-tree-dse
+Dump each function after applying dead store elimination.  The file
+name is made by appending @file{.dse} to the source file name.
+
+@item phiopt
+@opindex fdump-tree-phiopt
+Dump each function after optimizing PHI nodes into straightline code.  The file
+name is made by appending @file{.phiopt} to the source file name.
+
+@item forwprop
+@opindex fdump-tree-forwprop
+Dump each function after forward propagating single use variables.  The file
+name is made by appending @file{.forwprop} to the source file name.
+
+@item copyrename
+@opindex fdump-tree-copyrename
+Dump each function after applying the copy rename optimization.  The file
+name is made by appending @file{.copyrename} to the source file name.
+
+@item nrv
+@opindex fdump-tree-nrv
+Dump each function after applying the named return value optimization on
+generic trees.  The file name is made by appending @file{.nrv} to the source
+file name.
+
+@item vect
+@opindex fdump-tree-vect
+Dump each function after applying vectorization of loops.  The file name is
+made by appending @file{.vect} to the source file name.
+
+@item slp
+@opindex fdump-tree-slp
+Dump each function after applying vectorization of basic blocks.  The file name
+is made by appending @file{.slp} to the source file name.
+
+@item vrp
+@opindex fdump-tree-vrp
+Dump each function after Value Range Propagation (VRP).  The file name
+is made by appending @file{.vrp} to the source file name.
+
+@item all
+@opindex fdump-tree-all
+Enable all the available tree dumps with the flags provided in this option.
+@end table
+
+@item -fopt-info
+@itemx -fopt-info-@var{options}
+@itemx -fopt-info-@var{options}=@var{filename}
+@opindex fopt-info
+Controls optimization dumps from various optimization passes. If the
+@samp{-@var{options}} form is used, @var{options} is a list of
+@samp{-} separated options to select the dump details and
+optimizations.  If @var{options} is not specified, it defaults to
+@option{all} for details and @option{optall} for optimization
+groups. If the @var{filename} is not specified, it defaults to
+@file{stderr}. Note that the output @var{filename} will be overwritten
+in case of multiple translation units. If a combined output from
+multiple translation units is desired, @file{stderr} should be used
+instead.
+
+The options can be divided into two groups, 1) options describing the
+verbosity of the dump, and 2) options describing which optimizations
+should be included. The options from both the groups can be freely
+mixed as they are non-overlapping. However, in case of any conflicts,
+the latter options override the earlier options on the command
+line. Though multiple -fopt-info options are accepted, only one of
+them can have @option{=filename}. If other filenames are provided then
+all but the first one are ignored.
+
+The dump verbosity has the following options
+
+@table @samp
+@item optimized
+Print information when an optimization is successfully applied. It is
+up to a pass to decide which information is relevant. For example, the
+vectorizer passes print the source location of loops which got
+successfully vectorized.
+@item missed
+Print information about missed optimizations. Individual passes
+control which information to include in the output. For example,
+
+@smallexample
+gcc -O2 -ftree-vectorize -fopt-info-vec-missed
+@end smallexample
+
+will print information about missed optimization opportunities from
+vectorization passes on stderr.
+@item note
+Print verbose information about optimizations, such as certain
+transformations, more detailed messages about decisions etc.
+@item all
+Print detailed optimization information. This includes
+@var{optimized}, @var{missed}, and @var{note}.
+@end table
+
+The second set of options describes a group of optimizations and may
+include one or more of the following.
+
+@table @samp
+@item ipa
+Enable dumps from all interprocedural optimizations.
+@item loop
+Enable dumps from all loop optimizations.
+@item inline
+Enable dumps from all inlining optimizations.
+@item vec
+Enable dumps from all vectorization optimizations.
+@end table
+
+For example,
+@smallexample
+gcc -O3 -fopt-info-missed=missed.all
+@end smallexample
+
+outputs missed optimization report from all the passes into
+@file{missed.all}.
+
+As another example,
+@smallexample
+gcc -O3 -fopt-info-inline-optimized-missed=inline.txt
+@end smallexample
+
+will output information about missed optimizations as well as
+optimized locations from all the inlining passes into
+@file{inline.txt}.
+
+If the @var{filename} is provided, then the dumps from all the
+applicable optimizations are concatenated into the @file{filename}.
+Otherwise the dump is output onto @file{stderr}. If @var{options} is
+omitted, it defaults to @option{all-optall}, which means dump all
+available optimization info from all the passes. In the following
+example, all optimization info is output on to @file{stderr}.
+
+@smallexample
+gcc -O3 -fopt-info
+@end smallexample
+
+Note that @option{-fopt-info-vec-missed} behaves the same as
+@option{-fopt-info-missed-vec}.
+
+As another example, consider
+
+@smallexample
+gcc -fopt-info-vec-missed=vec.miss -fopt-info-loop-optimized=loop.opt
+@end smallexample
+
+Here the two output filenames @file{vec.miss} and @file{loop.opt} are
+in conflict since only one output file is allowed. In this case, only
+the first option takes effect and the subsequent options are
+ignored. Thus only the @file{vec.miss} is produced which cotaints
+dumps from the vectorizer about missed opportunities.
+
+@item -ftree-vectorizer-verbose=@var{n}
+@opindex ftree-vectorizer-verbose
+This option is deprecated and is implemented in terms of
+@option{-fopt-info}. Please use @option{-fopt-info-@var{kind}} form
+instead, where @var{kind} is one of the valid opt-info options. It
+prints additional optimization information.  For @var{n}=0 no
+diagnostic information is reported.  If @var{n}=1 the vectorizer
+reports each loop that got vectorized, and the total number of loops
+that got vectorized.  If @var{n}=2 the vectorizer reports locations
+which could not be vectorized and the reasons for those. For any
+higher verbosity levels all the analysis and transformation
+information from the vectorizer is reported.
+
+Note that the information output by @option{-ftree-vectorizer-verbose}
+option is sent to @file{stderr}. If the equivalent form
+@option{-fopt-info-@var{options}=@var{filename}} is used then the
+output is sent into @var{filename} instead.
+
+@item -frandom-seed=@var{string}
+@opindex frandom-seed
+This option provides a seed that GCC uses in place of
+random numbers in generating certain symbol names
+that have to be different in every compiled file.  It is also used to
+place unique stamps in coverage data files and the object files that
+produce them.  You can use the @option{-frandom-seed} option to produce
+reproducibly identical object files.
+
+The @var{string} should be different for every file you compile.
+
+@item -fsched-verbose=@var{n}
+@opindex fsched-verbose
+On targets that use instruction scheduling, this option controls the
+amount of debugging output the scheduler prints.  This information is
+written to standard error, unless @option{-fdump-rtl-sched1} or
+@option{-fdump-rtl-sched2} is specified, in which case it is output
+to the usual dump listing file, @file{.sched1} or @file{.sched2}
+respectively.  However for @var{n} greater than nine, the output is
+always printed to standard error.
+
+For @var{n} greater than zero, @option{-fsched-verbose} outputs the
+same information as @option{-fdump-rtl-sched1} and @option{-fdump-rtl-sched2}.
+For @var{n} greater than one, it also output basic block probabilities,
+detailed ready list information and unit/insn info.  For @var{n} greater
+than two, it includes RTL at abort point, control-flow and regions info.
+And for @var{n} over four, @option{-fsched-verbose} also includes
+dependence info.
+
+@item -save-temps
+@itemx -save-temps=cwd
+@opindex save-temps
+Store the usual ``temporary'' intermediate files permanently; place them
+in the current directory and name them based on the source file.  Thus,
+compiling @file{foo.c} with @option{-c -save-temps} produces files
+@file{foo.i} and @file{foo.s}, as well as @file{foo.o}.  This creates a
+preprocessed @file{foo.i} output file even though the compiler now
+normally uses an integrated preprocessor.
+
+When used in combination with the @option{-x} command-line option,
+@option{-save-temps} is sensible enough to avoid over writing an
+input source file with the same extension as an intermediate file.
+The corresponding intermediate file may be obtained by renaming the
+source file before using @option{-save-temps}.
+
+If you invoke GCC in parallel, compiling several different source
+files that share a common base name in different subdirectories or the
+same source file compiled for multiple output destinations, it is
+likely that the different parallel compilers will interfere with each
+other, and overwrite the temporary files.  For instance:
+
+@smallexample
+gcc -save-temps -o outdir1/foo.o indir1/foo.c&
+gcc -save-temps -o outdir2/foo.o indir2/foo.c&
+@end smallexample
+
+may result in @file{foo.i} and @file{foo.o} being written to
+simultaneously by both compilers.
+
+@item -save-temps=obj
+@opindex save-temps=obj
+Store the usual ``temporary'' intermediate files permanently.  If the
+@option{-o} option is used, the temporary files are based on the
+object file.  If the @option{-o} option is not used, the
+@option{-save-temps=obj} switch behaves like @option{-save-temps}.
+
+For example:
+
+@smallexample
+gcc -save-temps=obj -c foo.c
+gcc -save-temps=obj -c bar.c -o dir/xbar.o
+gcc -save-temps=obj foobar.c -o dir2/yfoobar
+@end smallexample
+
+@noindent
+creates @file{foo.i}, @file{foo.s}, @file{dir/xbar.i},
+@file{dir/xbar.s}, @file{dir2/yfoobar.i}, @file{dir2/yfoobar.s}, and
+@file{dir2/yfoobar.o}.
+
+@item -time@r{[}=@var{file}@r{]}
+@opindex time
+Report the CPU time taken by each subprocess in the compilation
+sequence.  For C source files, this is the compiler proper and assembler
+(plus the linker if linking is done).
+
+Without the specification of an output file, the output looks like this:
+
+@smallexample
+# cc1 0.12 0.01
+# as 0.00 0.01
+@end smallexample
+
+The first number on each line is the ``user time'', that is time spent
+executing the program itself.  The second number is ``system time'',
+time spent executing operating system routines on behalf of the program.
+Both numbers are in seconds.
+
+With the specification of an output file, the output is appended to the
+named file, and it looks like this:
+
+@smallexample
+0.12 0.01 cc1 @var{options}
+0.00 0.01 as @var{options}
+@end smallexample
+
+The ``user time'' and the ``system time'' are moved before the program
+name, and the options passed to the program are displayed, so that one
+can later tell what file was being compiled, and with which options.
+
+@item -fvar-tracking
+@opindex fvar-tracking
+Run variable tracking pass.  It computes where variables are stored at each
+position in code.  Better debugging information is then generated
+(if the debugging information format supports this information).
+
+It is enabled by default when compiling with optimization (@option{-Os},
+@option{-O}, @option{-O2}, @dots{}), debugging information (@option{-g}) and
+the debug info format supports it.
+
+@item -fvar-tracking-assignments
+@opindex fvar-tracking-assignments
+@opindex fno-var-tracking-assignments
+Annotate assignments to user variables early in the compilation and
+attempt to carry the annotations over throughout the compilation all the
+way to the end, in an attempt to improve debug information while
+optimizing.  Use of @option{-gdwarf-4} is recommended along with it.
+
+It can be enabled even if var-tracking is disabled, in which case
+annotations are created and maintained, but discarded at the end.
+
+@item -fvar-tracking-assignments-toggle
+@opindex fvar-tracking-assignments-toggle
+@opindex fno-var-tracking-assignments-toggle
+Toggle @option{-fvar-tracking-assignments}, in the same way that
+@option{-gtoggle} toggles @option{-g}.
+
+@item -print-file-name=@var{library}
+@opindex print-file-name
+Print the full absolute name of the library file @var{library} that
+would be used when linking---and don't do anything else.  With this
+option, GCC does not compile or link anything; it just prints the
+file name.
+
+@item -print-multi-directory
+@opindex print-multi-directory
+Print the directory name corresponding to the multilib selected by any
+other switches present in the command line.  This directory is supposed
+to exist in @env{GCC_EXEC_PREFIX}.
+
+@item -print-multi-lib
+@opindex print-multi-lib
+Print the mapping from multilib directory names to compiler switches
+that enable them.  The directory name is separated from the switches by
+@samp{;}, and each switch starts with an @samp{@@} instead of the
+@samp{-}, without spaces between multiple switches.  This is supposed to
+ease shell processing.
+
+@item -print-multi-os-directory
+@opindex print-multi-os-directory
+Print the path to OS libraries for the selected
+multilib, relative to some @file{lib} subdirectory.  If OS libraries are
+present in the @file{lib} subdirectory and no multilibs are used, this is
+usually just @file{.}, if OS libraries are present in @file{lib@var{suffix}}
+sibling directories this prints e.g.@: @file{../lib64}, @file{../lib} or
+@file{../lib32}, or if OS libraries are present in @file{lib/@var{subdir}}
+subdirectories it prints e.g.@: @file{amd64}, @file{sparcv9} or @file{ev6}.
+
+@item -print-multiarch
+@opindex print-multiarch
+Print the path to OS libraries for the selected multiarch,
+relative to some @file{lib} subdirectory.
+
+@item -print-prog-name=@var{program}
+@opindex print-prog-name
+Like @option{-print-file-name}, but searches for a program such as @samp{cpp}.
+
+@item -print-libgcc-file-name
+@opindex print-libgcc-file-name
+Same as @option{-print-file-name=libgcc.a}.
+
+This is useful when you use @option{-nostdlib} or @option{-nodefaultlibs}
+but you do want to link with @file{libgcc.a}.  You can do:
+
+@smallexample
+gcc -nostdlib @var{files}@dots{} `gcc -print-libgcc-file-name`
+@end smallexample
+
+@item -print-search-dirs
+@opindex print-search-dirs
+Print the name of the configured installation directory and a list of
+program and library directories @command{gcc} searches---and don't do anything else.
+
+This is useful when @command{gcc} prints the error message
+@samp{installation problem, cannot exec cpp0: No such file or directory}.
+To resolve this you either need to put @file{cpp0} and the other compiler
+components where @command{gcc} expects to find them, or you can set the environment
+variable @env{GCC_EXEC_PREFIX} to the directory where you installed them.
+Don't forget the trailing @samp{/}.
+@xref{Environment Variables}.
+
+@item -print-sysroot
+@opindex print-sysroot
+Print the target sysroot directory that is used during
+compilation.  This is the target sysroot specified either at configure
+time or using the @option{--sysroot} option, possibly with an extra
+suffix that depends on compilation options.  If no target sysroot is
+specified, the option prints nothing.
+
+@item -print-sysroot-headers-suffix
+@opindex print-sysroot-headers-suffix
+Print the suffix added to the target sysroot when searching for
+headers, or give an error if the compiler is not configured with such
+a suffix---and don't do anything else.
+
+@item -dumpmachine
+@opindex dumpmachine
+Print the compiler's target machine (for example,
+@samp{i686-pc-linux-gnu})---and don't do anything else.
+
+@item -dumpversion
+@opindex dumpversion
+Print the compiler version (for example, @samp{3.0})---and don't do
+anything else.
+
+@item -dumpspecs
+@opindex dumpspecs
+Print the compiler's built-in specs---and don't do anything else.  (This
+is used when GCC itself is being built.)  @xref{Spec Files}.
+
+@item -fno-eliminate-unused-debug-types
+@opindex feliminate-unused-debug-types
+@opindex fno-eliminate-unused-debug-types
+Normally, when producing DWARF 2 output, GCC avoids producing debug symbol 
+output for types that are nowhere used in the source file being compiled.
+Sometimes it is useful to have GCC emit debugging
+information for all types declared in a compilation
+unit, regardless of whether or not they are actually used
+in that compilation unit, for example 
+if, in the debugger, you want to cast a value to a type that is
+not actually used in your program (but is declared).  More often,
+however, this results in a significant amount of wasted space.
+@end table
+
+@node Optimize Options
+@section Options That Control Optimization
+@cindex optimize options
+@cindex options, optimization
+
+These options control various sorts of optimizations.
+
+Without any optimization option, the compiler's goal is to reduce the
+cost of compilation and to make debugging produce the expected
+results.  Statements are independent: if you stop the program with a
+breakpoint between statements, you can then assign a new value to any
+variable or change the program counter to any other statement in the
+function and get exactly the results you expect from the source
+code.
+
+Turning on optimization flags makes the compiler attempt to improve
+the performance and/or code size at the expense of compilation time
+and possibly the ability to debug the program.
+
+The compiler performs optimization based on the knowledge it has of the
+program.  Compiling multiple files at once to a single output file mode allows
+the compiler to use information gained from all of the files when compiling
+each of them.
+
+Not all optimizations are controlled directly by a flag.  Only
+optimizations that have a flag are listed in this section.
+
+Most optimizations are only enabled if an @option{-O} level is set on
+the command line.  Otherwise they are disabled, even if individual
+optimization flags are specified.
+
+Depending on the target and how GCC was configured, a slightly different
+set of optimizations may be enabled at each @option{-O} level than
+those listed here.  You can invoke GCC with @option{-Q --help=optimizers}
+to find out the exact set of optimizations that are enabled at each level.
+@xref{Overall Options}, for examples.
+
+@table @gcctabopt
+@item -O
+@itemx -O1
+@opindex O
+@opindex O1
+Optimize.  Optimizing compilation takes somewhat more time, and a lot
+more memory for a large function.
+
+With @option{-O}, the compiler tries to reduce code size and execution
+time, without performing any optimizations that take a great deal of
+compilation time.
+
+@option{-O} turns on the following optimization flags:
+@gccoptlist{
+-fauto-inc-dec @gol
+-fcompare-elim @gol
+-fcprop-registers @gol
+-fdce @gol
+-fdefer-pop @gol
+-fdelayed-branch @gol
+-fdse @gol
+-fguess-branch-probability @gol
+-fif-conversion2 @gol
+-fif-conversion @gol
+-fipa-pure-const @gol
+-fipa-profile @gol
+-fipa-reference @gol
+-fmerge-constants
+-fsplit-wide-types @gol
+-ftree-bit-ccp @gol
+-ftree-builtin-call-dce @gol
+-ftree-ccp @gol
+-ftree-ch @gol
+-ftree-copyrename @gol
+-ftree-dce @gol
+-ftree-dominator-opts @gol
+-ftree-dse @gol
+-ftree-forwprop @gol
+-ftree-fre @gol
+-ftree-phiprop @gol
+-ftree-slsr @gol
+-ftree-sra @gol
+-ftree-pta @gol
+-ftree-ter @gol
+-funit-at-a-time}
+
+@option{-O} also turns on @option{-fomit-frame-pointer} on machines
+where doing so does not interfere with debugging.
+
+@item -O2
+@opindex O2
+Optimize even more.  GCC performs nearly all supported optimizations
+that do not involve a space-speed tradeoff.
+As compared to @option{-O}, this option increases both compilation time
+and the performance of the generated code.
+
+@option{-O2} turns on all optimization flags specified by @option{-O}.  It
+also turns on the following optimization flags:
+@gccoptlist{-fthread-jumps @gol
+-falign-functions  -falign-jumps @gol
+-falign-loops  -falign-labels @gol
+-fcaller-saves @gol
+-fcrossjumping @gol
+-fcse-follow-jumps  -fcse-skip-blocks @gol
+-fdelete-null-pointer-checks @gol
+-fdevirtualize @gol
+-fexpensive-optimizations @gol
+-fgcse  -fgcse-lm  @gol
+-fhoist-adjacent-loads @gol
+-finline-small-functions @gol
+-findirect-inlining @gol
+-fipa-sra @gol
+-foptimize-sibling-calls @gol
+-fpartial-inlining @gol
+-fpeephole2 @gol
+-fregmove @gol
+-freorder-blocks  -freorder-functions @gol
+-frerun-cse-after-loop  @gol
+-fsched-interblock  -fsched-spec @gol
+-fschedule-insns  -fschedule-insns2 @gol
+-fstrict-aliasing -fstrict-overflow @gol
+-ftree-switch-conversion -ftree-tail-merge @gol
+-ftree-pre @gol
+-ftree-vrp}
+
+Please note the warning under @option{-fgcse} about
+invoking @option{-O2} on programs that use computed gotos.
+
+@item -O3
+@opindex O3
+Optimize yet more.  @option{-O3} turns on all optimizations specified
+by @option{-O2} and also turns on the @option{-finline-functions},
+@option{-funswitch-loops}, @option{-fpredictive-commoning},
+@option{-fgcse-after-reload}, @option{-ftree-vectorize},
+@option{-fvect-cost-model},
+@option{-ftree-partial-pre} and @option{-fipa-cp-clone} options.
+
+@item -O0
+@opindex O0
+Reduce compilation time and make debugging produce the expected
+results.  This is the default.
+
+@item -Os
+@opindex Os
+Optimize for size.  @option{-Os} enables all @option{-O2} optimizations that
+do not typically increase code size.  It also performs further
+optimizations designed to reduce code size.
+
+@option{-Os} disables the following optimization flags:
+@gccoptlist{-falign-functions  -falign-jumps  -falign-loops @gol
+-falign-labels  -freorder-blocks  -freorder-blocks-and-partition @gol
+-fprefetch-loop-arrays  -ftree-vect-loop-version}
+
+@item -Ofast
+@opindex Ofast
+Disregard strict standards compliance.  @option{-Ofast} enables all
+@option{-O3} optimizations.  It also enables optimizations that are not
+valid for all standard-compliant programs.
+It turns on @option{-ffast-math} and the Fortran-specific
+@option{-fno-protect-parens} and @option{-fstack-arrays}.
+
+@item -Og
+@opindex Og
+Optimize debugging experience.  @option{-Og} enables optimizations
+that do not interfere with debugging. It should be the optimization
+level of choice for the standard edit-compile-debug cycle, offering
+a reasonable level of optimization while maintaining fast compilation
+and a good debugging experience.
+
+If you use multiple @option{-O} options, with or without level numbers,
+the last such option is the one that is effective.
+@end table
+
+Options of the form @option{-f@var{flag}} specify machine-independent
+flags.  Most flags have both positive and negative forms; the negative
+form of @option{-ffoo} is @option{-fno-foo}.  In the table
+below, only one of the forms is listed---the one you typically 
+use.  You can figure out the other form by either removing @samp{no-}
+or adding it.
+
+The following options control specific optimizations.  They are either
+activated by @option{-O} options or are related to ones that are.  You
+can use the following flags in the rare cases when ``fine-tuning'' of
+optimizations to be performed is desired.
+
+@table @gcctabopt
+@item -fno-default-inline
+@opindex fno-default-inline
+Do not make member functions inline by default merely because they are
+defined inside the class scope (C++ only).  Otherwise, when you specify
+@w{@option{-O}}, member functions defined inside class scope are compiled
+inline by default; i.e., you don't need to add @samp{inline} in front of
+the member function name.
+
+@item -fno-defer-pop
+@opindex fno-defer-pop
+Always pop the arguments to each function call as soon as that function
+returns.  For machines that must pop arguments after a function call,
+the compiler normally lets arguments accumulate on the stack for several
+function calls and pops them all at once.
+
+Disabled at levels @option{-O}, @option{-O2}, @option{-O3}, @option{-Os}.
+
+@item -fforward-propagate
+@opindex fforward-propagate
+Perform a forward propagation pass on RTL@.  The pass tries to combine two
+instructions and checks if the result can be simplified.  If loop unrolling
+is active, two passes are performed and the second is scheduled after
+loop unrolling.
+
+This option is enabled by default at optimization levels @option{-O},
+@option{-O2}, @option{-O3}, @option{-Os}.
+
+@item -ffp-contract=@var{style}
+@opindex ffp-contract
+@option{-ffp-contract=off} disables floating-point expression contraction.
+@option{-ffp-contract=fast} enables floating-point expression contraction
+such as forming of fused multiply-add operations if the target has
+native support for them.
+@option{-ffp-contract=on} enables floating-point expression contraction
+if allowed by the language standard.  This is currently not implemented
+and treated equal to @option{-ffp-contract=off}.
+
+The default is @option{-ffp-contract=fast}.
+
+@item -fomit-frame-pointer
+@opindex fomit-frame-pointer
+Don't keep the frame pointer in a register for functions that
+don't need one.  This avoids the instructions to save, set up and
+restore frame pointers; it also makes an extra register available
+in many functions.  @strong{It also makes debugging impossible on
+some machines.}
+
+On some machines, such as the VAX, this flag has no effect, because
+the standard calling sequence automatically handles the frame pointer
+and nothing is saved by pretending it doesn't exist.  The
+machine-description macro @code{FRAME_POINTER_REQUIRED} controls
+whether a target machine supports this flag.  @xref{Registers,,Register
+Usage, gccint, GNU Compiler Collection (GCC) Internals}.
+
+Starting with GCC version 4.6, the default setting (when not optimizing for
+size) for 32-bit GNU/Linux x86 and 32-bit Darwin x86 targets has been changed to
+@option{-fomit-frame-pointer}.  The default can be reverted to
+@option{-fno-omit-frame-pointer} by configuring GCC with the
+@option{--enable-frame-pointer} configure option.
+
+Enabled at levels @option{-O}, @option{-O2}, @option{-O3}, @option{-Os}.
+
+@item -foptimize-sibling-calls
+@opindex foptimize-sibling-calls
+Optimize sibling and tail recursive calls.
+
+Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}.
+
+@item -fno-inline
+@opindex fno-inline
+Do not expand any functions inline apart from those marked with
+the @code{always_inline} attribute.  This is the default when not
+optimizing.
+
+Single functions can be exempted from inlining by marking them
+with the @code{noinline} attribute.
+
+@item -finline-small-functions
+@opindex finline-small-functions
+Integrate functions into their callers when their body is smaller than expected
+function call code (so overall size of program gets smaller).  The compiler
+heuristically decides which functions are simple enough to be worth integrating
+in this way.  This inlining applies to all functions, even those not declared
+inline.
+
+Enabled at level @option{-O2}.
+
+@item -findirect-inlining
+@opindex findirect-inlining
+Inline also indirect calls that are discovered to be known at compile
+time thanks to previous inlining.  This option has any effect only
+when inlining itself is turned on by the @option{-finline-functions}
+or @option{-finline-small-functions} options.
+
+Enabled at level @option{-O2}.
+
+@item -finline-functions
+@opindex finline-functions
+Consider all functions for inlining, even if they are not declared inline.
+The compiler heuristically decides which functions are worth integrating
+in this way.
+
+If all calls to a given function are integrated, and the function is
+declared @code{static}, then the function is normally not output as
+assembler code in its own right.
+
+Enabled at level @option{-O3}.
+
+@item -finline-functions-called-once
+@opindex finline-functions-called-once
+Consider all @code{static} functions called once for inlining into their
+caller even if they are not marked @code{inline}.  If a call to a given
+function is integrated, then the function is not output as assembler code
+in its own right.
+
+Enabled at levels @option{-O1}, @option{-O2}, @option{-O3} and @option{-Os}.
+
+@item -fearly-inlining
+@opindex fearly-inlining
+Inline functions marked by @code{always_inline} and functions whose body seems
+smaller than the function call overhead early before doing
+@option{-fprofile-generate} instrumentation and real inlining pass.  Doing so
+makes profiling significantly cheaper and usually inlining faster on programs
+having large chains of nested wrapper functions.
+
+Enabled by default.
+
+@item -fipa-sra
+@opindex fipa-sra
+Perform interprocedural scalar replacement of aggregates, removal of
+unused parameters and replacement of parameters passed by reference
+by parameters passed by value.
+
+Enabled at levels @option{-O2}, @option{-O3} and @option{-Os}.
+
+@item -finline-limit=@var{n}
+@opindex finline-limit
+By default, GCC limits the size of functions that can be inlined.  This flag
+allows coarse control of this limit.  @var{n} is the size of functions that
+can be inlined in number of pseudo instructions.
+
+Inlining is actually controlled by a number of parameters, which may be
+specified individually by using @option{--param @var{name}=@var{value}}.
+The @option{-finline-limit=@var{n}} option sets some of these parameters
+as follows:
+
+@table @gcctabopt
+@item max-inline-insns-single
+is set to @var{n}/2.
+@item max-inline-insns-auto
+is set to @var{n}/2.
+@end table
+
+See below for a documentation of the individual
+parameters controlling inlining and for the defaults of these parameters.
+
+@emph{Note:} there may be no value to @option{-finline-limit} that results
+in default behavior.
+
+@emph{Note:} pseudo instruction represents, in this particular context, an
+abstract measurement of function's size.  In no way does it represent a count
+of assembly instructions and as such its exact meaning might change from one
+release to an another.
+
+@item -fno-keep-inline-dllexport
+@opindex -fno-keep-inline-dllexport
+This is a more fine-grained version of @option{-fkeep-inline-functions},
+which applies only to functions that are declared using the @code{dllexport}
+attribute or declspec (@xref{Function Attributes,,Declaring Attributes of
+Functions}.)
+
+@item -fkeep-inline-functions
+@opindex fkeep-inline-functions
+In C, emit @code{static} functions that are declared @code{inline}
+into the object file, even if the function has been inlined into all
+of its callers.  This switch does not affect functions using the
+@code{extern inline} extension in GNU C90@.  In C++, emit any and all
+inline functions into the object file.
+
+@item -fkeep-static-consts
+@opindex fkeep-static-consts
+Emit variables declared @code{static const} when optimization isn't turned
+on, even if the variables aren't referenced.
+
+GCC enables this option by default.  If you want to force the compiler to
+check if a variable is referenced, regardless of whether or not
+optimization is turned on, use the @option{-fno-keep-static-consts} option.
+
+@item -fmerge-constants
+@opindex fmerge-constants
+Attempt to merge identical constants (string constants and floating-point
+constants) across compilation units.
+
+This option is the default for optimized compilation if the assembler and
+linker support it.  Use @option{-fno-merge-constants} to inhibit this
+behavior.
+
+Enabled at levels @option{-O}, @option{-O2}, @option{-O3}, @option{-Os}.
+
+@item -fmerge-all-constants
+@opindex fmerge-all-constants
+Attempt to merge identical constants and identical variables.
+
+This option implies @option{-fmerge-constants}.  In addition to
+@option{-fmerge-constants} this considers e.g.@: even constant initialized
+arrays or initialized constant variables with integral or floating-point
+types.  Languages like C or C++ require each variable, including multiple
+instances of the same variable in recursive calls, to have distinct locations,
+so using this option results in non-conforming
+behavior.
+
+@item -fmodulo-sched
+@opindex fmodulo-sched
+Perform swing modulo scheduling immediately before the first scheduling
+pass.  This pass looks at innermost loops and reorders their
+instructions by overlapping different iterations.
+
+@item -fmodulo-sched-allow-regmoves
+@opindex fmodulo-sched-allow-regmoves
+Perform more aggressive SMS-based modulo scheduling with register moves
+allowed.  By setting this flag certain anti-dependences edges are
+deleted, which triggers the generation of reg-moves based on the
+life-range analysis.  This option is effective only with
+@option{-fmodulo-sched} enabled.
+
+@item -fno-branch-count-reg
+@opindex fno-branch-count-reg
+Do not use ``decrement and branch'' instructions on a count register,
+but instead generate a sequence of instructions that decrement a
+register, compare it against zero, then branch based upon the result.
+This option is only meaningful on architectures that support such
+instructions, which include x86, PowerPC, IA-64 and S/390.
+
+The default is @option{-fbranch-count-reg}.
+
+@item -fno-function-cse
+@opindex fno-function-cse
+Do not put function addresses in registers; make each instruction that
+calls a constant function contain the function's address explicitly.
+
+This option results in less efficient code, but some strange hacks
+that alter the assembler output may be confused by the optimizations
+performed when this option is not used.
+
+The default is @option{-ffunction-cse}
+
+@item -fno-zero-initialized-in-bss
+@opindex fno-zero-initialized-in-bss
+If the target supports a BSS section, GCC by default puts variables that
+are initialized to zero into BSS@.  This can save space in the resulting
+code.
+
+This option turns off this behavior because some programs explicitly
+rely on variables going to the data section---e.g., so that the
+resulting executable can find the beginning of that section and/or make
+assumptions based on that.
+
+The default is @option{-fzero-initialized-in-bss}.
+
+@item -fmudflap -fmudflapth -fmudflapir
+@opindex fmudflap
+@opindex fmudflapth
+@opindex fmudflapir
+@cindex bounds checking
+@cindex mudflap
+For front-ends that support it (C and C++), instrument all risky
+pointer/array dereferencing operations, some standard library
+string/heap functions, and some other associated constructs with
+range/validity tests.  Modules so instrumented should be immune to
+buffer overflows, invalid heap use, and some other classes of C/C++
+programming errors.  The instrumentation relies on a separate runtime
+library (@file{libmudflap}), which is linked into a program if
+@option{-fmudflap} is given at link time.  Run-time behavior of the
+instrumented program is controlled by the @env{MUDFLAP_OPTIONS}
+environment variable.  See @code{env MUDFLAP_OPTIONS=-help a.out}
+for its options.
+
+Use @option{-fmudflapth} instead of @option{-fmudflap} to compile and to
+link if your program is multi-threaded.  Use @option{-fmudflapir}, in
+addition to @option{-fmudflap} or @option{-fmudflapth}, if
+instrumentation should ignore pointer reads.  This produces less
+instrumentation (and therefore faster execution) and still provides
+some protection against outright memory corrupting writes, but allows
+erroneously read data to propagate within a program.
+
+@item -fthread-jumps
+@opindex fthread-jumps
+Perform optimizations that check to see if a jump branches to a
+location where another comparison subsumed by the first is found.  If
+so, the first branch is redirected to either the destination of the
+second branch or a point immediately following it, depending on whether
+the condition is known to be true or false.
+
+Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}.
+
+@item -fsplit-wide-types
+@opindex fsplit-wide-types
+When using a type that occupies multiple registers, such as @code{long
+long} on a 32-bit system, split the registers apart and allocate them
+independently.  This normally generates better code for those types,
+but may make debugging more difficult.
+
+Enabled at levels @option{-O}, @option{-O2}, @option{-O3},
+@option{-Os}.
+
+@item -fcse-follow-jumps
+@opindex fcse-follow-jumps
+In common subexpression elimination (CSE), scan through jump instructions
+when the target of the jump is not reached by any other path.  For
+example, when CSE encounters an @code{if} statement with an
+@code{else} clause, CSE follows the jump when the condition
+tested is false.
+
+Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}.
+
+@item -fcse-skip-blocks
+@opindex fcse-skip-blocks
+This is similar to @option{-fcse-follow-jumps}, but causes CSE to
+follow jumps that conditionally skip over blocks.  When CSE
+encounters a simple @code{if} statement with no else clause,
+@option{-fcse-skip-blocks} causes CSE to follow the jump around the
+body of the @code{if}.
+
+Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}.
+
+@item -frerun-cse-after-loop
+@opindex frerun-cse-after-loop
+Re-run common subexpression elimination after loop optimizations are
+performed.
+
+Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}.
+
+@item -fgcse
+@opindex fgcse
+Perform a global common subexpression elimination pass.
+This pass also performs global constant and copy propagation.
+
+@emph{Note:} When compiling a program using computed gotos, a GCC
+extension, you may get better run-time performance if you disable
+the global common subexpression elimination pass by adding
+@option{-fno-gcse} to the command line.
+
+Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}.
+
+@item -fgcse-lm
+@opindex fgcse-lm
+When @option{-fgcse-lm} is enabled, global common subexpression elimination
+attempts to move loads that are only killed by stores into themselves.  This
+allows a loop containing a load/store sequence to be changed to a load outside
+the loop, and a copy/store within the loop.
+
+Enabled by default when @option{-fgcse} is enabled.
+
+@item -fgcse-sm
+@opindex fgcse-sm
+When @option{-fgcse-sm} is enabled, a store motion pass is run after
+global common subexpression elimination.  This pass attempts to move
+stores out of loops.  When used in conjunction with @option{-fgcse-lm},
+loops containing a load/store sequence can be changed to a load before
+the loop and a store after the loop.
+
+Not enabled at any optimization level.
+
+@item -fgcse-las
+@opindex fgcse-las
+When @option{-fgcse-las} is enabled, the global common subexpression
+elimination pass eliminates redundant loads that come after stores to the
+same memory location (both partial and full redundancies).
+
+Not enabled at any optimization level.
+
+@item -fgcse-after-reload
+@opindex fgcse-after-reload
+When @option{-fgcse-after-reload} is enabled, a redundant load elimination
+pass is performed after reload.  The purpose of this pass is to clean up
+redundant spilling.
+
+@item -faggressive-loop-optimizations
+@opindex faggressive-loop-optimizations
+This option tells the loop optimizer to use language constraints to
+derive bounds for the number of iterations of a loop.  This assumes that
+loop code does not invoke undefined behavior by for example causing signed
+integer overflows or out-of-bound array accesses.  The bounds for the
+number of iterations of a loop are used to guide loop unrolling and peeling
+and loop exit test optimizations.
+This option is enabled by default.
+
+@item -funsafe-loop-optimizations
+@opindex funsafe-loop-optimizations
+This option tells the loop optimizer to assume that loop indices do not
+overflow, and that loops with nontrivial exit condition are not
+infinite.  This enables a wider range of loop optimizations even if
+the loop optimizer itself cannot prove that these assumptions are valid.
+If you use @option{-Wunsafe-loop-optimizations}, the compiler warns you
+if it finds this kind of loop.
+
+@item -fcrossjumping
+@opindex fcrossjumping
+Perform cross-jumping transformation.
+This transformation unifies equivalent code and saves code size.  The
+resulting code may or may not perform better than without cross-jumping.
+
+Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}.
+
+@item -fauto-inc-dec
+@opindex fauto-inc-dec
+Combine increments or decrements of addresses with memory accesses.
+This pass is always skipped on architectures that do not have
+instructions to support this.  Enabled by default at @option{-O} and
+higher on architectures that support this.
+
+@item -fdce
+@opindex fdce
+Perform dead code elimination (DCE) on RTL@.
+Enabled by default at @option{-O} and higher.
+
+@item -fdse
+@opindex fdse
+Perform dead store elimination (DSE) on RTL@.
+Enabled by default at @option{-O} and higher.
+
+@item -fif-conversion
+@opindex fif-conversion
+Attempt to transform conditional jumps into branch-less equivalents.  This
+includes use of conditional moves, min, max, set flags and abs instructions, and
+some tricks doable by standard arithmetics.  The use of conditional execution
+on chips where it is available is controlled by @code{if-conversion2}.
+
+Enabled at levels @option{-O}, @option{-O2}, @option{-O3}, @option{-Os}.
+
+@item -fif-conversion2
+@opindex fif-conversion2
+Use conditional execution (where available) to transform conditional jumps into
+branch-less equivalents.
+
+Enabled at levels @option{-O}, @option{-O2}, @option{-O3}, @option{-Os}.
+
+@item -fdelete-null-pointer-checks
+@opindex fdelete-null-pointer-checks
+Assume that programs cannot safely dereference null pointers, and that
+no code or data element resides there.  This enables simple constant
+folding optimizations at all optimization levels.  In addition, other
+optimization passes in GCC use this flag to control global dataflow
+analyses that eliminate useless checks for null pointers; these assume
+that if a pointer is checked after it has already been dereferenced,
+it cannot be null.
+
+Note however that in some environments this assumption is not true.
+Use @option{-fno-delete-null-pointer-checks} to disable this optimization
+for programs that depend on that behavior.
+
+Some targets, especially embedded ones, disable this option at all levels.
+Otherwise it is enabled at all levels: @option{-O0}, @option{-O1},
+@option{-O2}, @option{-O3}, @option{-Os}.  Passes that use the information
+are enabled independently at different optimization levels.
+
+@item -fdevirtualize
+@opindex fdevirtualize
+Attempt to convert calls to virtual functions to direct calls.  This
+is done both within a procedure and interprocedurally as part of
+indirect inlining (@code{-findirect-inlining}) and interprocedural constant
+propagation (@option{-fipa-cp}).
+Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}.
+
+@item -fexpensive-optimizations
+@opindex fexpensive-optimizations
+Perform a number of minor optimizations that are relatively expensive.
+
+Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}.
+
+@item -free
+@opindex free
+Attempt to remove redundant extension instructions.  This is especially
+helpful for the x86-64 architecture, which implicitly zero-extends in 64-bit
+registers after writing to their lower 32-bit half.
+
+Enabled for x86 at levels @option{-O2}, @option{-O3}.
+
+@item -foptimize-register-move
+@itemx -fregmove
+@opindex foptimize-register-move
+@opindex fregmove
+Attempt to reassign register numbers in move instructions and as
+operands of other simple instructions in order to maximize the amount of
+register tying.  This is especially helpful on machines with two-operand
+instructions.
+
+Note @option{-fregmove} and @option{-foptimize-register-move} are the same
+optimization.
+
+Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}.
+
+@item -fira-algorithm=@var{algorithm}
+Use the specified coloring algorithm for the integrated register
+allocator.  The @var{algorithm} argument can be @samp{priority}, which
+specifies Chow's priority coloring, or @samp{CB}, which specifies
+Chaitin-Briggs coloring.  Chaitin-Briggs coloring is not implemented
+for all architectures, but for those targets that do support it, it is
+the default because it generates better code.
+
+@item -fira-region=@var{region}
+Use specified regions for the integrated register allocator.  The
+@var{region} argument should be one of the following:
+
+@table @samp
+
+@item all
+Use all loops as register allocation regions.
+This can give the best results for machines with a small and/or
+irregular register set.
+
+@item mixed
+Use all loops except for loops with small register pressure 
+as the regions.  This value usually gives
+the best results in most cases and for most architectures,
+and is enabled by default when compiling with optimization for speed
+(@option{-O}, @option{-O2}, @dots{}).
+
+@item one
+Use all functions as a single region.  
+This typically results in the smallest code size, and is enabled by default for
+@option{-Os} or @option{-O0}.
+
+@end table
+
+@item -fira-hoist-pressure
+@opindex fira-hoist-pressure
+Use IRA to evaluate register pressure in the code hoisting pass for
+decisions to hoist expressions.  This option usually results in smaller
+code, but it can slow the compiler down.
+
+This option is enabled at level @option{-Os} for all targets.
+
+@item -fira-loop-pressure
+@opindex fira-loop-pressure
+Use IRA to evaluate register pressure in loops for decisions to move
+loop invariants.  This option usually results in generation
+of faster and smaller code on machines with large register files (>= 32
+registers), but it can slow the compiler down.
+
+This option is enabled at level @option{-O3} for some targets.
+
+@item -fno-ira-share-save-slots
+@opindex fno-ira-share-save-slots
+Disable sharing of stack slots used for saving call-used hard
+registers living through a call.  Each hard register gets a
+separate stack slot, and as a result function stack frames are
+larger.
+
+@item -fno-ira-share-spill-slots
+@opindex fno-ira-share-spill-slots
+Disable sharing of stack slots allocated for pseudo-registers.  Each
+pseudo-register that does not get a hard register gets a separate
+stack slot, and as a result function stack frames are larger.
+
+@item -fira-verbose=@var{n}
+@opindex fira-verbose
+Control the verbosity of the dump file for the integrated register allocator.
+The default value is 5.  If the value @var{n} is greater or equal to 10,
+the dump output is sent to stderr using the same format as @var{n} minus 10.
+
+@item -fdelayed-branch
+@opindex fdelayed-branch
+If supported for the target machine, attempt to reorder instructions
+to exploit instruction slots available after delayed branch
+instructions.
+
+Enabled at levels @option{-O}, @option{-O2}, @option{-O3}, @option{-Os}.
+
+@item -fschedule-insns
+@opindex fschedule-insns
+If supported for the target machine, attempt to reorder instructions to
+eliminate execution stalls due to required data being unavailable.  This
+helps machines that have slow floating point or memory load instructions
+by allowing other instructions to be issued until the result of the load
+or floating-point instruction is required.
+
+Enabled at levels @option{-O2}, @option{-O3}.
+
+@item -fschedule-insns2
+@opindex fschedule-insns2
+Similar to @option{-fschedule-insns}, but requests an additional pass of
+instruction scheduling after register allocation has been done.  This is
+especially useful on machines with a relatively small number of
+registers and where memory load instructions take more than one cycle.
+
+Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}.
+
+@item -fno-sched-interblock
+@opindex fno-sched-interblock
+Don't schedule instructions across basic blocks.  This is normally
+enabled by default when scheduling before register allocation, i.e.@:
+with @option{-fschedule-insns} or at @option{-O2} or higher.
+
+@item -fno-sched-spec
+@opindex fno-sched-spec
+Don't allow speculative motion of non-load instructions.  This is normally
+enabled by default when scheduling before register allocation, i.e.@:
+with @option{-fschedule-insns} or at @option{-O2} or higher.
+
+@item -fsched-pressure
+@opindex fsched-pressure
+Enable register pressure sensitive insn scheduling before register
+allocation.  This only makes sense when scheduling before register
+allocation is enabled, i.e.@: with @option{-fschedule-insns} or at
+@option{-O2} or higher.  Usage of this option can improve the
+generated code and decrease its size by preventing register pressure
+increase above the number of available hard registers and subsequent
+spills in register allocation.
+
+@item -fsched-spec-load
+@opindex fsched-spec-load
+Allow speculative motion of some load instructions.  This only makes
+sense when scheduling before register allocation, i.e.@: with
+@option{-fschedule-insns} or at @option{-O2} or higher.
+
+@item -fsched-spec-load-dangerous
+@opindex fsched-spec-load-dangerous
+Allow speculative motion of more load instructions.  This only makes
+sense when scheduling before register allocation, i.e.@: with
+@option{-fschedule-insns} or at @option{-O2} or higher.
+
+@item -fsched-stalled-insns
+@itemx -fsched-stalled-insns=@var{n}
+@opindex fsched-stalled-insns
+Define how many insns (if any) can be moved prematurely from the queue
+of stalled insns into the ready list during the second scheduling pass.
+@option{-fno-sched-stalled-insns} means that no insns are moved
+prematurely, @option{-fsched-stalled-insns=0} means there is no limit
+on how many queued insns can be moved prematurely.
+@option{-fsched-stalled-insns} without a value is equivalent to
+@option{-fsched-stalled-insns=1}.
+
+@item -fsched-stalled-insns-dep
+@itemx -fsched-stalled-insns-dep=@var{n}
+@opindex fsched-stalled-insns-dep
+Define how many insn groups (cycles) are examined for a dependency
+on a stalled insn that is a candidate for premature removal from the queue
+of stalled insns.  This has an effect only during the second scheduling pass,
+and only if @option{-fsched-stalled-insns} is used.
+@option{-fno-sched-stalled-insns-dep} is equivalent to
+@option{-fsched-stalled-insns-dep=0}.
+@option{-fsched-stalled-insns-dep} without a value is equivalent to
+@option{-fsched-stalled-insns-dep=1}.
+
+@item -fsched2-use-superblocks
+@opindex fsched2-use-superblocks
+When scheduling after register allocation, use superblock scheduling.
+This allows motion across basic block boundaries,
+resulting in faster schedules.  This option is experimental, as not all machine
+descriptions used by GCC model the CPU closely enough to avoid unreliable
+results from the algorithm.
+
+This only makes sense when scheduling after register allocation, i.e.@: with
+@option{-fschedule-insns2} or at @option{-O2} or higher.
+
+@item -fsched-group-heuristic
+@opindex fsched-group-heuristic
+Enable the group heuristic in the scheduler.  This heuristic favors
+the instruction that belongs to a schedule group.  This is enabled
+by default when scheduling is enabled, i.e.@: with @option{-fschedule-insns}
+or @option{-fschedule-insns2} or at @option{-O2} or higher.
+
+@item -fsched-critical-path-heuristic
+@opindex fsched-critical-path-heuristic
+Enable the critical-path heuristic in the scheduler.  This heuristic favors
+instructions on the critical path.  This is enabled by default when
+scheduling is enabled, i.e.@: with @option{-fschedule-insns}
+or @option{-fschedule-insns2} or at @option{-O2} or higher.
+
+@item -fsched-spec-insn-heuristic
+@opindex fsched-spec-insn-heuristic
+Enable the speculative instruction heuristic in the scheduler.  This
+heuristic favors speculative instructions with greater dependency weakness.
+This is enabled by default when scheduling is enabled, i.e.@:
+with @option{-fschedule-insns} or @option{-fschedule-insns2}
+or at @option{-O2} or higher.
+
+@item -fsched-rank-heuristic
+@opindex fsched-rank-heuristic
+Enable the rank heuristic in the scheduler.  This heuristic favors
+the instruction belonging to a basic block with greater size or frequency.
+This is enabled by default when scheduling is enabled, i.e.@:
+with @option{-fschedule-insns} or @option{-fschedule-insns2} or
+at @option{-O2} or higher.
+
+@item -fsched-last-insn-heuristic
+@opindex fsched-last-insn-heuristic
+Enable the last-instruction heuristic in the scheduler.  This heuristic
+favors the instruction that is less dependent on the last instruction
+scheduled.  This is enabled by default when scheduling is enabled,
+i.e.@: with @option{-fschedule-insns} or @option{-fschedule-insns2} or
+at @option{-O2} or higher.
+
+@item -fsched-dep-count-heuristic
+@opindex fsched-dep-count-heuristic
+Enable the dependent-count heuristic in the scheduler.  This heuristic
+favors the instruction that has more instructions depending on it.
+This is enabled by default when scheduling is enabled, i.e.@:
+with @option{-fschedule-insns} or @option{-fschedule-insns2} or
+at @option{-O2} or higher.
+
+@item -freschedule-modulo-scheduled-loops
+@opindex freschedule-modulo-scheduled-loops
+Modulo scheduling is performed before traditional scheduling.  If a loop
+is modulo scheduled, later scheduling passes may change its schedule.  
+Use this option to control that behavior.
+
+@item -fselective-scheduling
+@opindex fselective-scheduling
+Schedule instructions using selective scheduling algorithm.  Selective
+scheduling runs instead of the first scheduler pass.
+
+@item -fselective-scheduling2
+@opindex fselective-scheduling2
+Schedule instructions using selective scheduling algorithm.  Selective
+scheduling runs instead of the second scheduler pass.
+
+@item -fsel-sched-pipelining
+@opindex fsel-sched-pipelining
+Enable software pipelining of innermost loops during selective scheduling.
+This option has no effect unless one of @option{-fselective-scheduling} or
+@option{-fselective-scheduling2} is turned on.
+
+@item -fsel-sched-pipelining-outer-loops
+@opindex fsel-sched-pipelining-outer-loops
+When pipelining loops during selective scheduling, also pipeline outer loops.
+This option has no effect unless @option{-fsel-sched-pipelining} is turned on.
+
+@item -fshrink-wrap
+@opindex fshrink-wrap
+Emit function prologues only before parts of the function that need it,
+rather than at the top of the function.  This flag is enabled by default at
+@option{-O} and higher.
+
+@item -fcaller-saves
+@opindex fcaller-saves
+Enable allocation of values to registers that are clobbered by
+function calls, by emitting extra instructions to save and restore the
+registers around such calls.  Such allocation is done only when it
+seems to result in better code.
+
+This option is always enabled by default on certain machines, usually
+those which have no call-preserved registers to use instead.
+
+Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}.
+
+@item -fcombine-stack-adjustments
+@opindex fcombine-stack-adjustments
+Tracks stack adjustments (pushes and pops) and stack memory references
+and then tries to find ways to combine them.
+
+Enabled by default at @option{-O1} and higher.
+
+@item -fconserve-stack
+@opindex fconserve-stack
+Attempt to minimize stack usage.  The compiler attempts to use less
+stack space, even if that makes the program slower.  This option
+implies setting the @option{large-stack-frame} parameter to 100
+and the @option{large-stack-frame-growth} parameter to 400.
+
+@item -ftree-reassoc
+@opindex ftree-reassoc
+Perform reassociation on trees.  This flag is enabled by default
+at @option{-O} and higher.
+
+@item -ftree-pre
+@opindex ftree-pre
+Perform partial redundancy elimination (PRE) on trees.  This flag is
+enabled by default at @option{-O2} and @option{-O3}.
+
+@item -ftree-partial-pre
+@opindex ftree-partial-pre
+Make partial redundancy elimination (PRE) more aggressive.  This flag is
+enabled by default at @option{-O3}.
+
+@item -ftree-forwprop
+@opindex ftree-forwprop
+Perform forward propagation on trees.  This flag is enabled by default
+at @option{-O} and higher.
+
+@item -ftree-fre
+@opindex ftree-fre
+Perform full redundancy elimination (FRE) on trees.  The difference
+between FRE and PRE is that FRE only considers expressions
+that are computed on all paths leading to the redundant computation.
+This analysis is faster than PRE, though it exposes fewer redundancies.
+This flag is enabled by default at @option{-O} and higher.
+
+@item -ftree-phiprop
+@opindex ftree-phiprop
+Perform hoisting of loads from conditional pointers on trees.  This
+pass is enabled by default at @option{-O} and higher.
+
+@item -fhoist-adjacent-loads
+@opindex hoist-adjacent-loads
+Speculatively hoist loads from both branches of an if-then-else if the
+loads are from adjacent locations in the same structure and the target
+architecture has a conditional move instruction.  This flag is enabled
+by default at @option{-O2} and higher.
+
+@item -ftree-copy-prop
+@opindex ftree-copy-prop
+Perform copy propagation on trees.  This pass eliminates unnecessary
+copy operations.  This flag is enabled by default at @option{-O} and
+higher.
+
+@item -fipa-pure-const
+@opindex fipa-pure-const
+Discover which functions are pure or constant.
+Enabled by default at @option{-O} and higher.
+
+@item -fipa-reference
+@opindex fipa-reference
+Discover which static variables do not escape the
+compilation unit.
+Enabled by default at @option{-O} and higher.
+
+@item -fipa-pta
+@opindex fipa-pta
+Perform interprocedural pointer analysis and interprocedural modification
+and reference analysis.  This option can cause excessive memory and
+compile-time usage on large compilation units.  It is not enabled by
+default at any optimization level.
+
+@item -fipa-profile
+@opindex fipa-profile
+Perform interprocedural profile propagation.  The functions called only from
+cold functions are marked as cold. Also functions executed once (such as
+@code{cold}, @code{noreturn}, static constructors or destructors) are identified. Cold
+functions and loop less parts of functions executed once are then optimized for
+size.
+Enabled by default at @option{-O} and higher.
+
+@item -fipa-cp
+@opindex fipa-cp
+Perform interprocedural constant propagation.
+This optimization analyzes the program to determine when values passed
+to functions are constants and then optimizes accordingly.
+This optimization can substantially increase performance
+if the application has constants passed to functions.
+This flag is enabled by default at @option{-O2}, @option{-Os} and @option{-O3}.
+
+@item -fipa-cp-clone
+@opindex fipa-cp-clone
+Perform function cloning to make interprocedural constant propagation stronger.
+When enabled, interprocedural constant propagation performs function cloning
+when externally visible function can be called with constant arguments.
+Because this optimization can create multiple copies of functions,
+it may significantly increase code size
+(see @option{--param ipcp-unit-growth=@var{value}}).
+This flag is enabled by default at @option{-O3}.
+
+@item -ftree-sink
+@opindex ftree-sink
+Perform forward store motion  on trees.  This flag is
+enabled by default at @option{-O} and higher.
+
+@item -ftree-bit-ccp
+@opindex ftree-bit-ccp
+Perform sparse conditional bit constant propagation on trees and propagate
+pointer alignment information.
+This pass only operates on local scalar variables and is enabled by default
+at @option{-O} and higher.  It requires that @option{-ftree-ccp} is enabled.
+
+@item -ftree-ccp
+@opindex ftree-ccp
+Perform sparse conditional constant propagation (CCP) on trees.  This
+pass only operates on local scalar variables and is enabled by default
+at @option{-O} and higher.
+
+@item -ftree-switch-conversion
+Perform conversion of simple initializations in a switch to
+initializations from a scalar array.  This flag is enabled by default
+at @option{-O2} and higher.
+
+@item -ftree-tail-merge
+Look for identical code sequences.  When found, replace one with a jump to the
+other.  This optimization is known as tail merging or cross jumping.  This flag
+is enabled by default at @option{-O2} and higher.  The compilation time
+in this pass can
+be limited using @option{max-tail-merge-comparisons} parameter and
+@option{max-tail-merge-iterations} parameter.
+
+@item -ftree-dce
+@opindex ftree-dce
+Perform dead code elimination (DCE) on trees.  This flag is enabled by
+default at @option{-O} and higher.
+
+@item -ftree-builtin-call-dce
+@opindex ftree-builtin-call-dce
+Perform conditional dead code elimination (DCE) for calls to built-in functions
+that may set @code{errno} but are otherwise side-effect free.  This flag is
+enabled by default at @option{-O2} and higher if @option{-Os} is not also
+specified.
+
+@item -ftree-dominator-opts
+@opindex ftree-dominator-opts
+Perform a variety of simple scalar cleanups (constant/copy
+propagation, redundancy elimination, range propagation and expression
+simplification) based on a dominator tree traversal.  This also
+performs jump threading (to reduce jumps to jumps). This flag is
+enabled by default at @option{-O} and higher.
+
+@item -ftree-dse
+@opindex ftree-dse
+Perform dead store elimination (DSE) on trees.  A dead store is a store into
+a memory location that is later overwritten by another store without
+any intervening loads.  In this case the earlier store can be deleted.  This
+flag is enabled by default at @option{-O} and higher.
+
+@item -ftree-ch
+@opindex ftree-ch
+Perform loop header copying on trees.  This is beneficial since it increases
+effectiveness of code motion optimizations.  It also saves one jump.  This flag
+is enabled by default at @option{-O} and higher.  It is not enabled
+for @option{-Os}, since it usually increases code size.
+
+@item -ftree-loop-optimize
+@opindex ftree-loop-optimize
+Perform loop optimizations on trees.  This flag is enabled by default
+at @option{-O} and higher.
+
+@item -ftree-loop-linear
+@opindex ftree-loop-linear
+Perform loop interchange transformations on tree.  Same as
+@option{-floop-interchange}.  To use this code transformation, GCC has
+to be configured with @option{--with-ppl} and @option{--with-cloog} to
+enable the Graphite loop transformation infrastructure.
+
+@item -floop-interchange
+@opindex floop-interchange
+Perform loop interchange transformations on loops.  Interchanging two
+nested loops switches the inner and outer loops.  For example, given a
+loop like:
+@smallexample
+DO J = 1, M
+  DO I = 1, N
+    A(J, I) = A(J, I) * C
+  ENDDO
+ENDDO
+@end smallexample
+loop interchange transforms the loop as if it were written:
+@smallexample
+DO I = 1, N
+  DO J = 1, M
+    A(J, I) = A(J, I) * C
+  ENDDO
+ENDDO
+@end smallexample
+which can be beneficial when @code{N} is larger than the caches,
+because in Fortran, the elements of an array are stored in memory
+contiguously by column, and the original loop iterates over rows,
+potentially creating at each access a cache miss.  This optimization
+applies to all the languages supported by GCC and is not limited to
+Fortran.  To use this code transformation, GCC has to be configured
+with @option{--with-ppl} and @option{--with-cloog} to enable the
+Graphite loop transformation infrastructure.
+
+@item -floop-strip-mine
+@opindex floop-strip-mine
+Perform loop strip mining transformations on loops.  Strip mining
+splits a loop into two nested loops.  The outer loop has strides
+equal to the strip size and the inner loop has strides of the
+original loop within a strip.  The strip length can be changed
+using the @option{loop-block-tile-size} parameter.  For example,
+given a loop like:
+@smallexample
+DO I = 1, N
+  A(I) = A(I) + C
+ENDDO
+@end smallexample
+loop strip mining transforms the loop as if it were written:
+@smallexample
+DO II = 1, N, 51
+  DO I = II, min (II + 50, N)
+    A(I) = A(I) + C
+  ENDDO
+ENDDO
+@end smallexample
+This optimization applies to all the languages supported by GCC and is
+not limited to Fortran.  To use this code transformation, GCC has to
+be configured with @option{--with-ppl} and @option{--with-cloog} to
+enable the Graphite loop transformation infrastructure.
+
+@item -floop-block
+@opindex floop-block
+Perform loop blocking transformations on loops.  Blocking strip mines
+each loop in the loop nest such that the memory accesses of the
+element loops fit inside caches.  The strip length can be changed
+using the @option{loop-block-tile-size} parameter.  For example, given
+a loop like:
+@smallexample
+DO I = 1, N
+  DO J = 1, M
+    A(J, I) = B(I) + C(J)
+  ENDDO
+ENDDO
+@end smallexample
+loop blocking transforms the loop as if it were written:
+@smallexample
+DO II = 1, N, 51
+  DO JJ = 1, M, 51
+    DO I = II, min (II + 50, N)
+      DO J = JJ, min (JJ + 50, M)
+        A(J, I) = B(I) + C(J)
+      ENDDO
+    ENDDO
+  ENDDO
+ENDDO
+@end smallexample
+which can be beneficial when @code{M} is larger than the caches,
+because the innermost loop iterates over a smaller amount of data
+which can be kept in the caches.  This optimization applies to all the
+languages supported by GCC and is not limited to Fortran.  To use this
+code transformation, GCC has to be configured with @option{--with-ppl}
+and @option{--with-cloog} to enable the Graphite loop transformation
+infrastructure.
+
+@item -fgraphite-identity
+@opindex fgraphite-identity
+Enable the identity transformation for graphite.  For every SCoP we generate
+the polyhedral representation and transform it back to gimple.  Using
+@option{-fgraphite-identity} we can check the costs or benefits of the
+GIMPLE -> GRAPHITE -> GIMPLE transformation.  Some minimal optimizations
+are also performed by the code generator CLooG, like index splitting and
+dead code elimination in loops.
+
+@item -floop-nest-optimize
+@opindex floop-nest-optimize
+Enable the ISL based loop nest optimizer.  This is a generic loop nest
+optimizer based on the Pluto optimization algorithms.  It calculates a loop
+structure optimized for data-locality and parallelism.  This option
+is experimental.
+
+@item -floop-parallelize-all
+@opindex floop-parallelize-all
+Use the Graphite data dependence analysis to identify loops that can
+be parallelized.  Parallelize all the loops that can be analyzed to
+not contain loop carried dependences without checking that it is
+profitable to parallelize the loops.
+
+@item -fcheck-data-deps
+@opindex fcheck-data-deps
+Compare the results of several data dependence analyzers.  This option
+is used for debugging the data dependence analyzers.
+
+@item -ftree-loop-if-convert
+Attempt to transform conditional jumps in the innermost loops to
+branch-less equivalents.  The intent is to remove control-flow from
+the innermost loops in order to improve the ability of the
+vectorization pass to handle these loops.  This is enabled by default
+if vectorization is enabled.
+
+@item -ftree-loop-if-convert-stores
+Attempt to also if-convert conditional jumps containing memory writes.
+This transformation can be unsafe for multi-threaded programs as it
+transforms conditional memory writes into unconditional memory writes.
+For example,
+@smallexample
+for (i = 0; i < N; i++)
+  if (cond)
+    A[i] = expr;
+@end smallexample
+is transformed to
+@smallexample
+for (i = 0; i < N; i++)
+  A[i] = cond ? expr : A[i];
+@end smallexample
+potentially producing data races.
+
+@item -ftree-loop-distribution
+Perform loop distribution.  This flag can improve cache performance on
+big loop bodies and allow further loop optimizations, like
+parallelization or vectorization, to take place.  For example, the loop
+@smallexample
+DO I = 1, N
+  A(I) = B(I) + C
+  D(I) = E(I) * F
+ENDDO
+@end smallexample
+is transformed to
+@smallexample
+DO I = 1, N
+   A(I) = B(I) + C
+ENDDO
+DO I = 1, N
+   D(I) = E(I) * F
+ENDDO
+@end smallexample
+
+@item -ftree-loop-distribute-patterns
+Perform loop distribution of patterns that can be code generated with
+calls to a library.  This flag is enabled by default at @option{-O3}.
+
+This pass distributes the initialization loops and generates a call to
+memset zero.  For example, the loop
+@smallexample
+DO I = 1, N
+  A(I) = 0
+  B(I) = A(I) + I
+ENDDO
+@end smallexample
+is transformed to
+@smallexample
+DO I = 1, N
+   A(I) = 0
+ENDDO
+DO I = 1, N
+   B(I) = A(I) + I
+ENDDO
+@end smallexample
+and the initialization loop is transformed into a call to memset zero.
+
+@item -ftree-loop-im
+@opindex ftree-loop-im
+Perform loop invariant motion on trees.  This pass moves only invariants that
+are hard to handle at RTL level (function calls, operations that expand to
+nontrivial sequences of insns).  With @option{-funswitch-loops} it also moves
+operands of conditions that are invariant out of the loop, so that we can use
+just trivial invariantness analysis in loop unswitching.  The pass also includes
+store motion.
+
+@item -ftree-loop-ivcanon
+@opindex ftree-loop-ivcanon
+Create a canonical counter for number of iterations in loops for which
+determining number of iterations requires complicated analysis.  Later
+optimizations then may determine the number easily.  Useful especially
+in connection with unrolling.
+
+@item -fivopts
+@opindex fivopts
+Perform induction variable optimizations (strength reduction, induction
+variable merging and induction variable elimination) on trees.
+
+@item -ftree-parallelize-loops=n
+@opindex ftree-parallelize-loops
+Parallelize loops, i.e., split their iteration space to run in n threads.
+This is only possible for loops whose iterations are independent
+and can be arbitrarily reordered.  The optimization is only
+profitable on multiprocessor machines, for loops that are CPU-intensive,
+rather than constrained e.g.@: by memory bandwidth.  This option
+implies @option{-pthread}, and thus is only supported on targets
+that have support for @option{-pthread}.
+
+@item -ftree-pta
+@opindex ftree-pta
+Perform function-local points-to analysis on trees.  This flag is
+enabled by default at @option{-O} and higher.
+
+@item -ftree-sra
+@opindex ftree-sra
+Perform scalar replacement of aggregates.  This pass replaces structure
+references with scalars to prevent committing structures to memory too
+early.  This flag is enabled by default at @option{-O} and higher.
+
+@item -ftree-copyrename
+@opindex ftree-copyrename
+Perform copy renaming on trees.  This pass attempts to rename compiler
+temporaries to other variables at copy locations, usually resulting in
+variable names which more closely resemble the original variables.  This flag
+is enabled by default at @option{-O} and higher.
+
+@item -ftree-coalesce-inlined-vars
+Tell the copyrename pass (see @option{-ftree-copyrename}) to attempt to
+combine small user-defined variables too, but only if they were inlined
+from other functions.  It is a more limited form of
+@option{-ftree-coalesce-vars}.  This may harm debug information of such
+inlined variables, but it will keep variables of the inlined-into
+function apart from each other, such that they are more likely to
+contain the expected values in a debugging session.  This was the
+default in GCC versions older than 4.7.
+
+@item -ftree-coalesce-vars
+Tell the copyrename pass (see @option{-ftree-copyrename}) to attempt to
+combine small user-defined variables too, instead of just compiler
+temporaries.  This may severely limit the ability to debug an optimized
+program compiled with @option{-fno-var-tracking-assignments}.  In the
+negated form, this flag prevents SSA coalescing of user variables,
+including inlined ones.  This option is enabled by default.
+
+@item -ftree-ter
+@opindex ftree-ter
+Perform temporary expression replacement during the SSA->normal phase.  Single
+use/single def temporaries are replaced at their use location with their
+defining expression.  This results in non-GIMPLE code, but gives the expanders
+much more complex trees to work on resulting in better RTL generation.  This is
+enabled by default at @option{-O} and higher.
+
+@item -ftree-slsr
+@opindex ftree-slsr
+Perform straight-line strength reduction on trees.  This recognizes related
+expressions involving multiplications and replaces them by less expensive
+calculations when possible.  This is enabled by default at @option{-O} and
+higher.
+
+@item -ftree-vectorize
+@opindex ftree-vectorize
+Perform loop vectorization on trees. This flag is enabled by default at
+@option{-O3}.
+
+@item -ftree-slp-vectorize
+@opindex ftree-slp-vectorize
+Perform basic block vectorization on trees. This flag is enabled by default at
+@option{-O3} and when @option{-ftree-vectorize} is enabled.
+
+@item -ftree-vect-loop-version
+@opindex ftree-vect-loop-version
+Perform loop versioning when doing loop vectorization on trees.  When a loop
+appears to be vectorizable except that data alignment or data dependence cannot
+be determined at compile time, then vectorized and non-vectorized versions of
+the loop are generated along with run-time checks for alignment or dependence
+to control which version is executed.  This option is enabled by default
+except at level @option{-Os} where it is disabled.
+
+@item -fvect-cost-model
+@opindex fvect-cost-model
+Enable cost model for vectorization.  This option is enabled by default at
+@option{-O3}.
+
+@item -ftree-vrp
+@opindex ftree-vrp
+Perform Value Range Propagation on trees.  This is similar to the
+constant propagation pass, but instead of values, ranges of values are
+propagated.  This allows the optimizers to remove unnecessary range
+checks like array bound checks and null pointer checks.  This is
+enabled by default at @option{-O2} and higher.  Null pointer check
+elimination is only done if @option{-fdelete-null-pointer-checks} is
+enabled.
+
+@item -ftracer
+@opindex ftracer
+Perform tail duplication to enlarge superblock size.  This transformation
+simplifies the control flow of the function allowing other optimizations to do
+a better job.
+
+@item -funroll-loops
+@opindex funroll-loops
+Unroll loops whose number of iterations can be determined at compile
+time or upon entry to the loop.  @option{-funroll-loops} implies
+@option{-frerun-cse-after-loop}.  This option makes code larger,
+and may or may not make it run faster.
+
+@item -funroll-all-loops
+@opindex funroll-all-loops
+Unroll all loops, even if their number of iterations is uncertain when
+the loop is entered.  This usually makes programs run more slowly.
+@option{-funroll-all-loops} implies the same options as
+@option{-funroll-loops},
+
+@item -fsplit-ivs-in-unroller
+@opindex fsplit-ivs-in-unroller
+Enables expression of values of induction variables in later iterations
+of the unrolled loop using the value in the first iteration.  This breaks
+long dependency chains, thus improving efficiency of the scheduling passes.
+
+A combination of @option{-fweb} and CSE is often sufficient to obtain the
+same effect.  However, that is not reliable in cases where the loop body
+is more complicated than a single basic block.  It also does not work at all
+on some architectures due to restrictions in the CSE pass.
+
+This optimization is enabled by default.
+
+@item -fvariable-expansion-in-unroller
+@opindex fvariable-expansion-in-unroller
+With this option, the compiler creates multiple copies of some
+local variables when unrolling a loop, which can result in superior code.
+
+@item -fpartial-inlining
+@opindex fpartial-inlining
+Inline parts of functions.  This option has any effect only
+when inlining itself is turned on by the @option{-finline-functions}
+or @option{-finline-small-functions} options.
+
+Enabled at level @option{-O2}.
+
+@item -fpredictive-commoning
+@opindex fpredictive-commoning
+Perform predictive commoning optimization, i.e., reusing computations
+(especially memory loads and stores) performed in previous
+iterations of loops.
+
+This option is enabled at level @option{-O3}.
+
+@item -fprefetch-loop-arrays
+@opindex fprefetch-loop-arrays
+If supported by the target machine, generate instructions to prefetch
+memory to improve the performance of loops that access large arrays.
+
+This option may generate better or worse code; results are highly
+dependent on the structure of loops within the source code.
+
+Disabled at level @option{-Os}.
+
+@item -fno-peephole
+@itemx -fno-peephole2
+@opindex fno-peephole
+@opindex fno-peephole2
+Disable any machine-specific peephole optimizations.  The difference
+between @option{-fno-peephole} and @option{-fno-peephole2} is in how they
+are implemented in the compiler; some targets use one, some use the
+other, a few use both.
+
+@option{-fpeephole} is enabled by default.
+@option{-fpeephole2} enabled at levels @option{-O2}, @option{-O3}, @option{-Os}.
+
+@item -fno-guess-branch-probability
+@opindex fno-guess-branch-probability
+Do not guess branch probabilities using heuristics.
+
+GCC uses heuristics to guess branch probabilities if they are
+not provided by profiling feedback (@option{-fprofile-arcs}).  These
+heuristics are based on the control flow graph.  If some branch probabilities
+are specified by @samp{__builtin_expect}, then the heuristics are
+used to guess branch probabilities for the rest of the control flow graph,
+taking the @samp{__builtin_expect} info into account.  The interactions
+between the heuristics and @samp{__builtin_expect} can be complex, and in
+some cases, it may be useful to disable the heuristics so that the effects
+of @samp{__builtin_expect} are easier to understand.
+
+The default is @option{-fguess-branch-probability} at levels
+@option{-O}, @option{-O2}, @option{-O3}, @option{-Os}.
+
+@item -freorder-blocks
+@opindex freorder-blocks
+Reorder basic blocks in the compiled function in order to reduce number of
+taken branches and improve code locality.
+
+Enabled at levels @option{-O2}, @option{-O3}.
+
+@item -freorder-blocks-and-partition
+@opindex freorder-blocks-and-partition
+In addition to reordering basic blocks in the compiled function, in order
+to reduce number of taken branches, partitions hot and cold basic blocks
+into separate sections of the assembly and .o files, to improve
+paging and cache locality performance.
+
+This optimization is automatically turned off in the presence of
+exception handling, for linkonce sections, for functions with a user-defined
+section attribute and on any architecture that does not support named
+sections.
+
+@item -freorder-functions
+@opindex freorder-functions
+Reorder functions in the object file in order to
+improve code locality.  This is implemented by using special
+subsections @code{.text.hot} for most frequently executed functions and
+@code{.text.unlikely} for unlikely executed functions.  Reordering is done by
+the linker so object file format must support named sections and linker must
+place them in a reasonable way.
+
+Also profile feedback must be available to make this option effective.  See
+@option{-fprofile-arcs} for details.
+
+Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}.
+
+@item -fstrict-aliasing
+@opindex fstrict-aliasing
+Allow the compiler to assume the strictest aliasing rules applicable to
+the language being compiled.  For C (and C++), this activates
+optimizations based on the type of expressions.  In particular, an
+object of one type is assumed never to reside at the same address as an
+object of a different type, unless the types are almost the same.  For
+example, an @code{unsigned int} can alias an @code{int}, but not a
+@code{void*} or a @code{double}.  A character type may alias any other
+type.
+
+@anchor{Type-punning}Pay special attention to code like this:
+@smallexample
+union a_union @{
+  int i;
+  double d;
+@};
+
+int f() @{
+  union a_union t;
+  t.d = 3.0;
+  return t.i;
+@}
+@end smallexample
+The practice of reading from a different union member than the one most
+recently written to (called ``type-punning'') is common.  Even with
+@option{-fstrict-aliasing}, type-punning is allowed, provided the memory
+is accessed through the union type.  So, the code above works as
+expected.  @xref{Structures unions enumerations and bit-fields
+implementation}.  However, this code might not:
+@smallexample
+int f() @{
+  union a_union t;
+  int* ip;
+  t.d = 3.0;
+  ip = &t.i;
+  return *ip;
+@}
+@end smallexample
+
+Similarly, access by taking the address, casting the resulting pointer
+and dereferencing the result has undefined behavior, even if the cast
+uses a union type, e.g.:
+@smallexample
+int f() @{
+  double d = 3.0;
+  return ((union a_union *) &d)->i;
+@}
+@end smallexample
+
+The @option{-fstrict-aliasing} option is enabled at levels
+@option{-O2}, @option{-O3}, @option{-Os}.
+
+@item -fstrict-overflow
+@opindex fstrict-overflow
+Allow the compiler to assume strict signed overflow rules, depending
+on the language being compiled.  For C (and C++) this means that
+overflow when doing arithmetic with signed numbers is undefined, which
+means that the compiler may assume that it does not happen.  This
+permits various optimizations.  For example, the compiler assumes
+that an expression like @code{i + 10 > i} is always true for
+signed @code{i}.  This assumption is only valid if signed overflow is
+undefined, as the expression is false if @code{i + 10} overflows when
+using twos complement arithmetic.  When this option is in effect any
+attempt to determine whether an operation on signed numbers 
+overflows must be written carefully to not actually involve overflow.
+
+This option also allows the compiler to assume strict pointer
+semantics: given a pointer to an object, if adding an offset to that
+pointer does not produce a pointer to the same object, the addition is
+undefined.  This permits the compiler to conclude that @code{p + u >
+p} is always true for a pointer @code{p} and unsigned integer
+@code{u}.  This assumption is only valid because pointer wraparound is
+undefined, as the expression is false if @code{p + u} overflows using
+twos complement arithmetic.
+
+See also the @option{-fwrapv} option.  Using @option{-fwrapv} means
+that integer signed overflow is fully defined: it wraps.  When
+@option{-fwrapv} is used, there is no difference between
+@option{-fstrict-overflow} and @option{-fno-strict-overflow} for
+integers.  With @option{-fwrapv} certain types of overflow are
+permitted.  For example, if the compiler gets an overflow when doing
+arithmetic on constants, the overflowed value can still be used with
+@option{-fwrapv}, but not otherwise.
+
+The @option{-fstrict-overflow} option is enabled at levels
+@option{-O2}, @option{-O3}, @option{-Os}.
+
+@item -falign-functions
+@itemx -falign-functions=@var{n}
+@opindex falign-functions
+Align the start of functions to the next power-of-two greater than
+@var{n}, skipping up to @var{n} bytes.  For instance,
+@option{-falign-functions=32} aligns functions to the next 32-byte
+boundary, but @option{-falign-functions=24} aligns to the next
+32-byte boundary only if this can be done by skipping 23 bytes or less.
+
+@option{-fno-align-functions} and @option{-falign-functions=1} are
+equivalent and mean that functions are not aligned.
+
+Some assemblers only support this flag when @var{n} is a power of two;
+in that case, it is rounded up.
+
+If @var{n} is not specified or is zero, use a machine-dependent default.
+
+Enabled at levels @option{-O2}, @option{-O3}.
+
+@item -falign-labels
+@itemx -falign-labels=@var{n}
+@opindex falign-labels
+Align all branch targets to a power-of-two boundary, skipping up to
+@var{n} bytes like @option{-falign-functions}.  This option can easily
+make code slower, because it must insert dummy operations for when the
+branch target is reached in the usual flow of the code.
+
+@option{-fno-align-labels} and @option{-falign-labels=1} are
+equivalent and mean that labels are not aligned.
+
+If @option{-falign-loops} or @option{-falign-jumps} are applicable and
+are greater than this value, then their values are used instead.
+
+If @var{n} is not specified or is zero, use a machine-dependent default
+which is very likely to be @samp{1}, meaning no alignment.
+
+Enabled at levels @option{-O2}, @option{-O3}.
+
+@item -falign-loops
+@itemx -falign-loops=@var{n}
+@opindex falign-loops
+Align loops to a power-of-two boundary, skipping up to @var{n} bytes
+like @option{-falign-functions}.  If the loops are
+executed many times, this makes up for any execution of the dummy
+operations.
+
+@option{-fno-align-loops} and @option{-falign-loops=1} are
+equivalent and mean that loops are not aligned.
+
+If @var{n} is not specified or is zero, use a machine-dependent default.
+
+Enabled at levels @option{-O2}, @option{-O3}.
+
+@item -falign-jumps
+@itemx -falign-jumps=@var{n}
+@opindex falign-jumps
+Align branch targets to a power-of-two boundary, for branch targets
+where the targets can only be reached by jumping, skipping up to @var{n}
+bytes like @option{-falign-functions}.  In this case, no dummy operations
+need be executed.
+
+@option{-fno-align-jumps} and @option{-falign-jumps=1} are
+equivalent and mean that loops are not aligned.
+
+If @var{n} is not specified or is zero, use a machine-dependent default.
+
+Enabled at levels @option{-O2}, @option{-O3}.
+
+@item -funit-at-a-time
+@opindex funit-at-a-time
+This option is left for compatibility reasons. @option{-funit-at-a-time}
+has no effect, while @option{-fno-unit-at-a-time} implies
+@option{-fno-toplevel-reorder} and @option{-fno-section-anchors}.
+
+Enabled by default.
+
+@item -fno-toplevel-reorder
+@opindex fno-toplevel-reorder
+Do not reorder top-level functions, variables, and @code{asm}
+statements.  Output them in the same order that they appear in the
+input file.  When this option is used, unreferenced static variables
+are not removed.  This option is intended to support existing code
+that relies on a particular ordering.  For new code, it is better to
+use attributes.
+
+Enabled at level @option{-O0}.  When disabled explicitly, it also implies
+@option{-fno-section-anchors}, which is otherwise enabled at @option{-O0} on some
+targets.
+
+@item -fweb
+@opindex fweb
+Constructs webs as commonly used for register allocation purposes and assign
+each web individual pseudo register.  This allows the register allocation pass
+to operate on pseudos directly, but also strengthens several other optimization
+passes, such as CSE, loop optimizer and trivial dead code remover.  It can,
+however, make debugging impossible, since variables no longer stay in a
+``home register''.
+
+Enabled by default with @option{-funroll-loops}.
+
+@item -fwhole-program
+@opindex fwhole-program
+Assume that the current compilation unit represents the whole program being
+compiled.  All public functions and variables with the exception of @code{main}
+and those merged by attribute @code{externally_visible} become static functions
+and in effect are optimized more aggressively by interprocedural optimizers.
+
+This option should not be used in combination with @code{-flto}.
+Instead relying on a linker plugin should provide safer and more precise
+information.
+
+@item -flto[=@var{n}]
+@opindex flto
+This option runs the standard link-time optimizer.  When invoked
+with source code, it generates GIMPLE (one of GCC's internal
+representations) and writes it to special ELF sections in the object
+file.  When the object files are linked together, all the function
+bodies are read from these ELF sections and instantiated as if they
+had been part of the same translation unit.
+
+To use the link-time optimizer, @option{-flto} needs to be specified at
+compile time and during the final link.  For example:
+
+@smallexample
+gcc -c -O2 -flto foo.c
+gcc -c -O2 -flto bar.c
+gcc -o myprog -flto -O2 foo.o bar.o
+@end smallexample
+
+The first two invocations to GCC save a bytecode representation
+of GIMPLE into special ELF sections inside @file{foo.o} and
+@file{bar.o}.  The final invocation reads the GIMPLE bytecode from
+@file{foo.o} and @file{bar.o}, merges the two files into a single
+internal image, and compiles the result as usual.  Since both
+@file{foo.o} and @file{bar.o} are merged into a single image, this
+causes all the interprocedural analyses and optimizations in GCC to
+work across the two files as if they were a single one.  This means,
+for example, that the inliner is able to inline functions in
+@file{bar.o} into functions in @file{foo.o} and vice-versa.
+
+Another (simpler) way to enable link-time optimization is:
+
+@smallexample
+gcc -o myprog -flto -O2 foo.c bar.c
+@end smallexample
+
+The above generates bytecode for @file{foo.c} and @file{bar.c},
+merges them together into a single GIMPLE representation and optimizes
+them as usual to produce @file{myprog}.
+
+The only important thing to keep in mind is that to enable link-time
+optimizations the @option{-flto} flag needs to be passed to both the
+compile and the link commands.
+
+To make whole program optimization effective, it is necessary to make
+certain whole program assumptions.  The compiler needs to know
+what functions and variables can be accessed by libraries and runtime
+outside of the link-time optimized unit.  When supported by the linker,
+the linker plugin (see @option{-fuse-linker-plugin}) passes information
+to the compiler about used and externally visible symbols.  When
+the linker plugin is not available, @option{-fwhole-program} should be
+used to allow the compiler to make these assumptions, which leads
+to more aggressive optimization decisions.
+
+Note that when a file is compiled with @option{-flto}, the generated
+object file is larger than a regular object file because it 
+contains GIMPLE bytecodes and the usual final code.  This means that
+object files with LTO information can be linked as normal object
+files; if @option{-flto} is not passed to the linker, no
+interprocedural optimizations are applied.
+
+Additionally, the optimization flags used to compile individual files
+are not necessarily related to those used at link time.  For instance,
+
+@smallexample
+gcc -c -O0 -flto foo.c
+gcc -c -O0 -flto bar.c
+gcc -o myprog -flto -O3 foo.o bar.o
+@end smallexample
+
+This produces individual object files with unoptimized assembler
+code, but the resulting binary @file{myprog} is optimized at
+@option{-O3}.  If, instead, the final binary is generated without
+@option{-flto}, then @file{myprog} is not optimized.
+
+When producing the final binary with @option{-flto}, GCC only
+applies link-time optimizations to those files that contain bytecode.
+Therefore, you can mix and match object files and libraries with
+GIMPLE bytecodes and final object code.  GCC automatically selects
+which files to optimize in LTO mode and which files to link without
+further processing.
+
+There are some code generation flags preserved by GCC when
+generating bytecodes, as they need to be used during the final link
+stage.  Currently, the following options are saved into the GIMPLE
+bytecode files: @option{-fPIC}, @option{-fcommon} and all the
+@option{-m} target flags.
+
+At link time, these options are read in and reapplied.  Note that the
+current implementation makes no attempt to recognize conflicting
+values for these options.  If different files have conflicting option
+values (e.g., one file is compiled with @option{-fPIC} and another
+isn't), the compiler simply uses the last value read from the
+bytecode files.  It is recommended, then, that you compile all the files
+participating in the same link with the same options.
+
+If LTO encounters objects with C linkage declared with incompatible
+types in separate translation units to be linked together (undefined
+behavior according to ISO C99 6.2.7), a non-fatal diagnostic may be
+issued.  The behavior is still undefined at run time.
+
+Another feature of LTO is that it is possible to apply interprocedural
+optimizations on files written in different languages.  This requires
+support in the language front end.  Currently, the C, C++ and
+Fortran front ends are capable of emitting GIMPLE bytecodes, so
+something like this should work:
+
+@smallexample
+gcc -c -flto foo.c
+g++ -c -flto bar.cc
+gfortran -c -flto baz.f90
+g++ -o myprog -flto -O3 foo.o bar.o baz.o -lgfortran
+@end smallexample
+
+Notice that the final link is done with @command{g++} to get the C++
+runtime libraries and @option{-lgfortran} is added to get the Fortran
+runtime libraries.  In general, when mixing languages in LTO mode, you
+should use the same link command options as when mixing languages in a
+regular (non-LTO) compilation; all you need to add is @option{-flto} to
+all the compile and link commands.
+
+If object files containing GIMPLE bytecode are stored in a library archive, say
+@file{libfoo.a}, it is possible to extract and use them in an LTO link if you
+are using a linker with plugin support.  To enable this feature, use
+the flag @option{-fuse-linker-plugin} at link time:
+
+@smallexample
+gcc -o myprog -O2 -flto -fuse-linker-plugin a.o b.o -lfoo
+@end smallexample
+
+With the linker plugin enabled, the linker extracts the needed
+GIMPLE files from @file{libfoo.a} and passes them on to the running GCC
+to make them part of the aggregated GIMPLE image to be optimized.
+
+If you are not using a linker with plugin support and/or do not
+enable the linker plugin, then the objects inside @file{libfoo.a}
+are extracted and linked as usual, but they do not participate
+in the LTO optimization process.
+
+Link-time optimizations do not require the presence of the whole program to
+operate.  If the program does not require any symbols to be exported, it is
+possible to combine @option{-flto} and @option{-fwhole-program} to allow
+the interprocedural optimizers to use more aggressive assumptions which may
+lead to improved optimization opportunities.
+Use of @option{-fwhole-program} is not needed when linker plugin is
+active (see @option{-fuse-linker-plugin}).
+
+The current implementation of LTO makes no
+attempt to generate bytecode that is portable between different
+types of hosts.  The bytecode files are versioned and there is a
+strict version check, so bytecode files generated in one version of
+GCC will not work with an older/newer version of GCC@.
+
+Link-time optimization does not work well with generation of debugging
+information.  Combining @option{-flto} with
+@option{-g} is currently experimental and expected to produce wrong
+results.
+
+If you specify the optional @var{n}, the optimization and code
+generation done at link time is executed in parallel using @var{n}
+parallel jobs by utilizing an installed @command{make} program.  The
+environment variable @env{MAKE} may be used to override the program
+used.  The default value for @var{n} is 1.
+
+You can also specify @option{-flto=jobserver} to use GNU make's
+job server mode to determine the number of parallel jobs. This
+is useful when the Makefile calling GCC is already executing in parallel.
+You must prepend a @samp{+} to the command recipe in the parent Makefile
+for this to work.  This option likely only works if @env{MAKE} is
+GNU make.
+
+This option is disabled by default.
+
+@item -flto-partition=@var{alg}
+@opindex flto-partition
+Specify the partitioning algorithm used by the link-time optimizer.
+The value is either @code{1to1} to specify a partitioning mirroring
+the original source files or @code{balanced} to specify partitioning
+into equally sized chunks (whenever possible) or @code{max} to create
+new partition for every symbol where possible.  Specifying @code{none}
+as an algorithm disables partitioning and streaming completely. 
+The default value is @code{balanced}. While @code{1to1} can be used
+as an workaround for various code ordering issues, the @code{max}
+partitioning is intended for internal testing only.
+
+@item -flto-compression-level=@var{n}
+This option specifies the level of compression used for intermediate
+language written to LTO object files, and is only meaningful in
+conjunction with LTO mode (@option{-flto}).  Valid
+values are 0 (no compression) to 9 (maximum compression).  Values
+outside this range are clamped to either 0 or 9.  If the option is not
+given, a default balanced compression setting is used.
+
+@item -flto-report
+Prints a report with internal details on the workings of the link-time
+optimizer.  The contents of this report vary from version to version.
+It is meant to be useful to GCC developers when processing object
+files in LTO mode (via @option{-flto}).
+
+Disabled by default.
+
+@item -fuse-linker-plugin
+Enables the use of a linker plugin during link-time optimization.  This
+option relies on plugin support in the linker, which is available in gold
+or in GNU ld 2.21 or newer.
+
+This option enables the extraction of object files with GIMPLE bytecode out
+of library archives. This improves the quality of optimization by exposing
+more code to the link-time optimizer.  This information specifies what
+symbols can be accessed externally (by non-LTO object or during dynamic
+linking).  Resulting code quality improvements on binaries (and shared
+libraries that use hidden visibility) are similar to @code{-fwhole-program}.
+See @option{-flto} for a description of the effect of this flag and how to
+use it.
+
+This option is enabled by default when LTO support in GCC is enabled
+and GCC was configured for use with
+a linker supporting plugins (GNU ld 2.21 or newer or gold).
+
+@item -ffat-lto-objects
+@opindex ffat-lto-objects
+Fat LTO objects are object files that contain both the intermediate language
+and the object code. This makes them usable for both LTO linking and normal
+linking. This option is effective only when compiling with @option{-flto}
+and is ignored at link time.
+
+@option{-fno-fat-lto-objects} improves compilation time over plain LTO, but
+requires the complete toolchain to be aware of LTO. It requires a linker with
+linker plugin support for basic functionality.  Additionally,
+@command{nm}, @command{ar} and @command{ranlib}
+need to support linker plugins to allow a full-featured build environment
+(capable of building static libraries etc).  GCC provides the @command{gcc-ar},
+@command{gcc-nm}, @command{gcc-ranlib} wrappers to pass the right options
+to these tools. With non fat LTO makefiles need to be modified to use them.
+
+The default is @option{-ffat-lto-objects} but this default is intended to
+change in future releases when linker plugin enabled environments become more
+common.
+
+@item -fcompare-elim
+@opindex fcompare-elim
+After register allocation and post-register allocation instruction splitting,
+identify arithmetic instructions that compute processor flags similar to a
+comparison operation based on that arithmetic.  If possible, eliminate the
+explicit comparison operation.
+
+This pass only applies to certain targets that cannot explicitly represent
+the comparison operation before register allocation is complete.
+
+Enabled at levels @option{-O}, @option{-O2}, @option{-O3}, @option{-Os}.
+
+@item -fuse-ld=bfd
+Use the @command{bfd} linker instead of the default linker.
+
+@item -fuse-ld=gold
+Use the @command{gold} linker instead of the default linker.
+
+@item -fcprop-registers
+@opindex fcprop-registers
+After register allocation and post-register allocation instruction splitting,
+perform a copy-propagation pass to try to reduce scheduling dependencies
+and occasionally eliminate the copy.
+
+Enabled at levels @option{-O}, @option{-O2}, @option{-O3}, @option{-Os}.
+
+@item -fprofile-correction
+@opindex fprofile-correction
+Profiles collected using an instrumented binary for multi-threaded programs may
+be inconsistent due to missed counter updates. When this option is specified,
+GCC uses heuristics to correct or smooth out such inconsistencies. By
+default, GCC emits an error message when an inconsistent profile is detected.
+
+@item -fprofile-dir=@var{path}
+@opindex fprofile-dir
+
+Set the directory to search for the profile data files in to @var{path}.
+This option affects only the profile data generated by
+@option{-fprofile-generate}, @option{-ftest-coverage}, @option{-fprofile-arcs}
+and used by @option{-fprofile-use} and @option{-fbranch-probabilities}
+and its related options.  Both absolute and relative paths can be used.
+By default, GCC uses the current directory as @var{path}, thus the
+profile data file appears in the same directory as the object file.
+
+@item -fprofile-generate
+@itemx -fprofile-generate=@var{path}
+@opindex fprofile-generate
+
+Enable options usually used for instrumenting application to produce
+profile useful for later recompilation with profile feedback based
+optimization.  You must use @option{-fprofile-generate} both when
+compiling and when linking your program.
+
+The following options are enabled: @code{-fprofile-arcs}, @code{-fprofile-values}, @code{-fvpt}.
+
+If @var{path} is specified, GCC looks at the @var{path} to find
+the profile feedback data files. See @option{-fprofile-dir}.
+
+@item -fprofile-use
+@itemx -fprofile-use=@var{path}
+@opindex fprofile-use
+Enable profile feedback directed optimizations, and optimizations
+generally profitable only with profile feedback available.
+
+The following options are enabled: @code{-fbranch-probabilities}, @code{-fvpt},
+@code{-funroll-loops}, @code{-fpeel-loops}, @code{-ftracer}, @code{-ftree-vectorize},
+@code{ftree-loop-distribute-patterns}
+
+By default, GCC emits an error message if the feedback profiles do not
+match the source code.  This error can be turned into a warning by using
+@option{-Wcoverage-mismatch}.  Note this may result in poorly optimized
+code.
+
+If @var{path} is specified, GCC looks at the @var{path} to find
+the profile feedback data files. See @option{-fprofile-dir}.
+@end table
+
+The following options control compiler behavior regarding floating-point 
+arithmetic.  These options trade off between speed and
+correctness.  All must be specifically enabled.
+
+@table @gcctabopt
+@item -ffloat-store
+@opindex ffloat-store
+Do not store floating-point variables in registers, and inhibit other
+options that might change whether a floating-point value is taken from a
+register or memory.
+
+@cindex floating-point precision
+This option prevents undesirable excess precision on machines such as
+the 68000 where the floating registers (of the 68881) keep more
+precision than a @code{double} is supposed to have.  Similarly for the
+x86 architecture.  For most programs, the excess precision does only
+good, but a few programs rely on the precise definition of IEEE floating
+point.  Use @option{-ffloat-store} for such programs, after modifying
+them to store all pertinent intermediate computations into variables.
+
+@item -fexcess-precision=@var{style}
+@opindex fexcess-precision
+This option allows further control over excess precision on machines
+where floating-point registers have more precision than the IEEE
+@code{float} and @code{double} types and the processor does not
+support operations rounding to those types.  By default,
+@option{-fexcess-precision=fast} is in effect; this means that
+operations are carried out in the precision of the registers and that
+it is unpredictable when rounding to the types specified in the source
+code takes place.  When compiling C, if
+@option{-fexcess-precision=standard} is specified then excess
+precision follows the rules specified in ISO C99; in particular,
+both casts and assignments cause values to be rounded to their
+semantic types (whereas @option{-ffloat-store} only affects
+assignments).  This option is enabled by default for C if a strict
+conformance option such as @option{-std=c99} is used.
+
+@opindex mfpmath
+@option{-fexcess-precision=standard} is not implemented for languages
+other than C, and has no effect if
+@option{-funsafe-math-optimizations} or @option{-ffast-math} is
+specified.  On the x86, it also has no effect if @option{-mfpmath=sse}
+or @option{-mfpmath=sse+387} is specified; in the former case, IEEE
+semantics apply without excess precision, and in the latter, rounding
+is unpredictable.
+
+@item -ffast-math
+@opindex ffast-math
+Sets @option{-fno-math-errno}, @option{-funsafe-math-optimizations},
+@option{-ffinite-math-only}, @option{-fno-rounding-math},
+@option{-fno-signaling-nans} and @option{-fcx-limited-range}.
+
+This option causes the preprocessor macro @code{__FAST_MATH__} to be defined.
+
+This option is not turned on by any @option{-O} option besides
+@option{-Ofast} since it can result in incorrect output for programs
+that depend on an exact implementation of IEEE or ISO rules/specifications
+for math functions. It may, however, yield faster code for programs
+that do not require the guarantees of these specifications.
+
+@item -fno-math-errno
+@opindex fno-math-errno
+Do not set @code{errno} after calling math functions that are executed
+with a single instruction, e.g., @code{sqrt}.  A program that relies on
+IEEE exceptions for math error handling may want to use this flag
+for speed while maintaining IEEE arithmetic compatibility.
+
+This option is not turned on by any @option{-O} option since
+it can result in incorrect output for programs that depend on
+an exact implementation of IEEE or ISO rules/specifications for
+math functions. It may, however, yield faster code for programs
+that do not require the guarantees of these specifications.
+
+The default is @option{-fmath-errno}.
+
+On Darwin systems, the math library never sets @code{errno}.  There is
+therefore no reason for the compiler to consider the possibility that
+it might, and @option{-fno-math-errno} is the default.
+
+@item -funsafe-math-optimizations
+@opindex funsafe-math-optimizations
+
+Allow optimizations for floating-point arithmetic that (a) assume
+that arguments and results are valid and (b) may violate IEEE or
+ANSI standards.  When used at link-time, it may include libraries
+or startup files that change the default FPU control word or other
+similar optimizations.
+
+This option is not turned on by any @option{-O} option since
+it can result in incorrect output for programs that depend on
+an exact implementation of IEEE or ISO rules/specifications for
+math functions. It may, however, yield faster code for programs
+that do not require the guarantees of these specifications.
+Enables @option{-fno-signed-zeros}, @option{-fno-trapping-math},
+@option{-fassociative-math} and @option{-freciprocal-math}.
+
+The default is @option{-fno-unsafe-math-optimizations}.
+
+@item -fassociative-math
+@opindex fassociative-math
+
+Allow re-association of operands in series of floating-point operations.
+This violates the ISO C and C++ language standard by possibly changing
+computation result.  NOTE: re-ordering may change the sign of zero as
+well as ignore NaNs and inhibit or create underflow or overflow (and
+thus cannot be used on code that relies on rounding behavior like
+@code{(x + 2**52) - 2**52}.  May also reorder floating-point comparisons
+and thus may not be used when ordered comparisons are required.
+This option requires that both @option{-fno-signed-zeros} and
+@option{-fno-trapping-math} be in effect.  Moreover, it doesn't make
+much sense with @option{-frounding-math}. For Fortran the option
+is automatically enabled when both @option{-fno-signed-zeros} and
+@option{-fno-trapping-math} are in effect.
+
+The default is @option{-fno-associative-math}.
+
+@item -freciprocal-math
+@opindex freciprocal-math
+
+Allow the reciprocal of a value to be used instead of dividing by
+the value if this enables optimizations.  For example @code{x / y}
+can be replaced with @code{x * (1/y)}, which is useful if @code{(1/y)}
+is subject to common subexpression elimination.  Note that this loses
+precision and increases the number of flops operating on the value.
+
+The default is @option{-fno-reciprocal-math}.
+
+@item -ffinite-math-only
+@opindex ffinite-math-only
+Allow optimizations for floating-point arithmetic that assume
+that arguments and results are not NaNs or +-Infs.
+
+This option is not turned on by any @option{-O} option since
+it can result in incorrect output for programs that depend on
+an exact implementation of IEEE or ISO rules/specifications for
+math functions. It may, however, yield faster code for programs
+that do not require the guarantees of these specifications.
+
+The default is @option{-fno-finite-math-only}.
+
+@item -fno-signed-zeros
+@opindex fno-signed-zeros
+Allow optimizations for floating-point arithmetic that ignore the
+signedness of zero.  IEEE arithmetic specifies the behavior of
+distinct +0.0 and @minus{}0.0 values, which then prohibits simplification
+of expressions such as x+0.0 or 0.0*x (even with @option{-ffinite-math-only}).
+This option implies that the sign of a zero result isn't significant.
+
+The default is @option{-fsigned-zeros}.
+
+@item -fno-trapping-math
+@opindex fno-trapping-math
+Compile code assuming that floating-point operations cannot generate
+user-visible traps.  These traps include division by zero, overflow,
+underflow, inexact result and invalid operation.  This option requires
+that @option{-fno-signaling-nans} be in effect.  Setting this option may
+allow faster code if one relies on ``non-stop'' IEEE arithmetic, for example.
+
+This option should never be turned on by any @option{-O} option since
+it can result in incorrect output for programs that depend on
+an exact implementation of IEEE or ISO rules/specifications for
+math functions.
+
+The default is @option{-ftrapping-math}.
+
+@item -frounding-math
+@opindex frounding-math
+Disable transformations and optimizations that assume default floating-point
+rounding behavior.  This is round-to-zero for all floating point
+to integer conversions, and round-to-nearest for all other arithmetic
+truncations.  This option should be specified for programs that change
+the FP rounding mode dynamically, or that may be executed with a
+non-default rounding mode.  This option disables constant folding of
+floating-point expressions at compile time (which may be affected by
+rounding mode) and arithmetic transformations that are unsafe in the
+presence of sign-dependent rounding modes.
+
+The default is @option{-fno-rounding-math}.
+
+This option is experimental and does not currently guarantee to
+disable all GCC optimizations that are affected by rounding mode.
+Future versions of GCC may provide finer control of this setting
+using C99's @code{FENV_ACCESS} pragma.  This command-line option
+will be used to specify the default state for @code{FENV_ACCESS}.
+
+@item -fsignaling-nans
+@opindex fsignaling-nans
+Compile code assuming that IEEE signaling NaNs may generate user-visible
+traps during floating-point operations.  Setting this option disables
+optimizations that may change the number of exceptions visible with
+signaling NaNs.  This option implies @option{-ftrapping-math}.
+
+This option causes the preprocessor macro @code{__SUPPORT_SNAN__} to
+be defined.
+
+The default is @option{-fno-signaling-nans}.
+
+This option is experimental and does not currently guarantee to
+disable all GCC optimizations that affect signaling NaN behavior.
+
+@item -fsingle-precision-constant
+@opindex fsingle-precision-constant
+Treat floating-point constants as single precision instead of
+implicitly converting them to double-precision constants.
+
+@item -fcx-limited-range
+@opindex fcx-limited-range
+When enabled, this option states that a range reduction step is not
+needed when performing complex division.  Also, there is no checking
+whether the result of a complex multiplication or division is @code{NaN
++ I*NaN}, with an attempt to rescue the situation in that case.  The
+default is @option{-fno-cx-limited-range}, but is enabled by
+@option{-ffast-math}.
+
+This option controls the default setting of the ISO C99
+@code{CX_LIMITED_RANGE} pragma.  Nevertheless, the option applies to
+all languages.
+
+@item -fcx-fortran-rules
+@opindex fcx-fortran-rules
+Complex multiplication and division follow Fortran rules.  Range
+reduction is done as part of complex division, but there is no checking
+whether the result of a complex multiplication or division is @code{NaN
++ I*NaN}, with an attempt to rescue the situation in that case.
+
+The default is @option{-fno-cx-fortran-rules}.
+
+@end table
+
+The following options control optimizations that may improve
+performance, but are not enabled by any @option{-O} options.  This
+section includes experimental options that may produce broken code.
+
+@table @gcctabopt
+@item -fbranch-probabilities
+@opindex fbranch-probabilities
+After running a program compiled with @option{-fprofile-arcs}
+(@pxref{Debugging Options,, Options for Debugging Your Program or
+@command{gcc}}), you can compile it a second time using
+@option{-fbranch-probabilities}, to improve optimizations based on
+the number of times each branch was taken.  When a program
+compiled with @option{-fprofile-arcs} exits, it saves arc execution
+counts to a file called @file{@var{sourcename}.gcda} for each source
+file.  The information in this data file is very dependent on the
+structure of the generated code, so you must use the same source code
+and the same optimization options for both compilations.
+
+With @option{-fbranch-probabilities}, GCC puts a
+@samp{REG_BR_PROB} note on each @samp{JUMP_INSN} and @samp{CALL_INSN}.
+These can be used to improve optimization.  Currently, they are only
+used in one place: in @file{reorg.c}, instead of guessing which path a
+branch is most likely to take, the @samp{REG_BR_PROB} values are used to
+exactly determine which path is taken more often.
+
+@item -fprofile-values
+@opindex fprofile-values
+If combined with @option{-fprofile-arcs}, it adds code so that some
+data about values of expressions in the program is gathered.
+
+With @option{-fbranch-probabilities}, it reads back the data gathered
+from profiling values of expressions for usage in optimizations.
+
+Enabled with @option{-fprofile-generate} and @option{-fprofile-use}.
+
+@item -fvpt
+@opindex fvpt
+If combined with @option{-fprofile-arcs}, this option instructs the compiler
+to add code to gather information about values of expressions.
+
+With @option{-fbranch-probabilities}, it reads back the data gathered
+and actually performs the optimizations based on them.
+Currently the optimizations include specialization of division operations
+using the knowledge about the value of the denominator.
+
+@item -frename-registers
+@opindex frename-registers
+Attempt to avoid false dependencies in scheduled code by making use
+of registers left over after register allocation.  This optimization
+most benefits processors with lots of registers.  Depending on the
+debug information format adopted by the target, however, it can
+make debugging impossible, since variables no longer stay in
+a ``home register''.
+
+Enabled by default with @option{-funroll-loops} and @option{-fpeel-loops}.
+
+@item -ftracer
+@opindex ftracer
+Perform tail duplication to enlarge superblock size.  This transformation
+simplifies the control flow of the function allowing other optimizations to do
+a better job.
+
+Enabled with @option{-fprofile-use}.
+
+@item -funroll-loops
+@opindex funroll-loops
+Unroll loops whose number of iterations can be determined at compile time or
+upon entry to the loop.  @option{-funroll-loops} implies
+@option{-frerun-cse-after-loop}, @option{-fweb} and @option{-frename-registers}.
+It also turns on complete loop peeling (i.e.@: complete removal of loops with
+a small constant number of iterations).  This option makes code larger, and may
+or may not make it run faster.
+
+Enabled with @option{-fprofile-use}.
+
+@item -funroll-all-loops
+@opindex funroll-all-loops
+Unroll all loops, even if their number of iterations is uncertain when
+the loop is entered.  This usually makes programs run more slowly.
+@option{-funroll-all-loops} implies the same options as
+@option{-funroll-loops}.
+
+@item -fpeel-loops
+@opindex fpeel-loops
+Peels loops for which there is enough information that they do not
+roll much (from profile feedback).  It also turns on complete loop peeling
+(i.e.@: complete removal of loops with small constant number of iterations).
+
+Enabled with @option{-fprofile-use}.
+
+@item -fmove-loop-invariants
+@opindex fmove-loop-invariants
+Enables the loop invariant motion pass in the RTL loop optimizer.  Enabled
+at level @option{-O1}
+
+@item -funswitch-loops
+@opindex funswitch-loops
+Move branches with loop invariant conditions out of the loop, with duplicates
+of the loop on both branches (modified according to result of the condition).
+
+@item -ffunction-sections
+@itemx -fdata-sections
+@opindex ffunction-sections
+@opindex fdata-sections
+Place each function or data item into its own section in the output
+file if the target supports arbitrary sections.  The name of the
+function or the name of the data item determines the section's name
+in the output file.
+
+Use these options on systems where the linker can perform optimizations
+to improve locality of reference in the instruction space.  Most systems
+using the ELF object format and SPARC processors running Solaris 2 have
+linkers with such optimizations.  AIX may have these optimizations in
+the future.
+
+Only use these options when there are significant benefits from doing
+so.  When you specify these options, the assembler and linker
+create larger object and executable files and are also slower.
+You cannot use @code{gprof} on all systems if you
+specify this option, and you may have problems with debugging if
+you specify both this option and @option{-g}.
+
+@item -fbranch-target-load-optimize
+@opindex fbranch-target-load-optimize
+Perform branch target register load optimization before prologue / epilogue
+threading.
+The use of target registers can typically be exposed only during reload,
+thus hoisting loads out of loops and doing inter-block scheduling needs
+a separate optimization pass.
+
+@item -fbranch-target-load-optimize2
+@opindex fbranch-target-load-optimize2
+Perform branch target register load optimization after prologue / epilogue
+threading.
+
+@item -fbtr-bb-exclusive
+@opindex fbtr-bb-exclusive
+When performing branch target register load optimization, don't reuse
+branch target registers within any basic block.
+
+@item -fstack-protector
+@opindex fstack-protector
+Emit extra code to check for buffer overflows, such as stack smashing
+attacks.  This is done by adding a guard variable to functions with
+vulnerable objects.  This includes functions that call @code{alloca}, and
+functions with buffers larger than 8 bytes.  The guards are initialized
+when a function is entered and then checked when the function exits.
+If a guard check fails, an error message is printed and the program exits.
+
+@item -fstack-protector-all
+@opindex fstack-protector-all
+Like @option{-fstack-protector} except that all functions are protected.
+
+@item -fsection-anchors
+@opindex fsection-anchors
+Try to reduce the number of symbolic address calculations by using
+shared ``anchor'' symbols to address nearby objects.  This transformation
+can help to reduce the number of GOT entries and GOT accesses on some
+targets.
+
+For example, the implementation of the following function @code{foo}:
+
+@smallexample
+static int a, b, c;
+int foo (void) @{ return a + b + c; @}
+@end smallexample
+
+@noindent
+usually calculates the addresses of all three variables, but if you
+compile it with @option{-fsection-anchors}, it accesses the variables
+from a common anchor point instead.  The effect is similar to the
+following pseudocode (which isn't valid C):
+
+@smallexample
+int foo (void)
+@{
+  register int *xr = &x;
+  return xr[&a - &x] + xr[&b - &x] + xr[&c - &x];
+@}
+@end smallexample
+
+Not all targets support this option.
+
+@item --param @var{name}=@var{value}
+@opindex param
+In some places, GCC uses various constants to control the amount of
+optimization that is done.  For example, GCC does not inline functions
+that contain more than a certain number of instructions.  You can
+control some of these constants on the command line using the
+@option{--param} option.
+
+The names of specific parameters, and the meaning of the values, are
+tied to the internals of the compiler, and are subject to change
+without notice in future releases.
+
+In each case, the @var{value} is an integer.  The allowable choices for
+@var{name} are:
+
+@table @gcctabopt
+@item predictable-branch-outcome
+When branch is predicted to be taken with probability lower than this threshold
+(in percent), then it is considered well predictable. The default is 10.
+
+@item max-crossjump-edges
+The maximum number of incoming edges to consider for cross-jumping.
+The algorithm used by @option{-fcrossjumping} is @math{O(N^2)} in
+the number of edges incoming to each block.  Increasing values mean
+more aggressive optimization, making the compilation time increase with
+probably small improvement in executable size.
+
+@item min-crossjump-insns
+The minimum number of instructions that must be matched at the end
+of two blocks before cross-jumping is performed on them.  This
+value is ignored in the case where all instructions in the block being
+cross-jumped from are matched.  The default value is 5.
+
+@item max-grow-copy-bb-insns
+The maximum code size expansion factor when copying basic blocks
+instead of jumping.  The expansion is relative to a jump instruction.
+The default value is 8.
+
+@item max-goto-duplication-insns
+The maximum number of instructions to duplicate to a block that jumps
+to a computed goto.  To avoid @math{O(N^2)} behavior in a number of
+passes, GCC factors computed gotos early in the compilation process,
+and unfactors them as late as possible.  Only computed jumps at the
+end of a basic blocks with no more than max-goto-duplication-insns are
+unfactored.  The default value is 8.
+
+@item max-delay-slot-insn-search
+The maximum number of instructions to consider when looking for an
+instruction to fill a delay slot.  If more than this arbitrary number of
+instructions are searched, the time savings from filling the delay slot
+are minimal, so stop searching.  Increasing values mean more
+aggressive optimization, making the compilation time increase with probably
+small improvement in execution time.
+
+@item max-delay-slot-live-search
+When trying to fill delay slots, the maximum number of instructions to
+consider when searching for a block with valid live register
+information.  Increasing this arbitrarily chosen value means more
+aggressive optimization, increasing the compilation time.  This parameter
+should be removed when the delay slot code is rewritten to maintain the
+control-flow graph.
+
+@item max-gcse-memory
+The approximate maximum amount of memory that can be allocated in
+order to perform the global common subexpression elimination
+optimization.  If more memory than specified is required, the
+optimization is not done.
+
+@item max-gcse-insertion-ratio
+If the ratio of expression insertions to deletions is larger than this value
+for any expression, then RTL PRE inserts or removes the expression and thus
+leaves partially redundant computations in the instruction stream.  The default value is 20.
+
+@item max-pending-list-length
+The maximum number of pending dependencies scheduling allows
+before flushing the current state and starting over.  Large functions
+with few branches or calls can create excessively large lists which
+needlessly consume memory and resources.
+
+@item max-modulo-backtrack-attempts
+The maximum number of backtrack attempts the scheduler should make
+when modulo scheduling a loop.  Larger values can exponentially increase
+compilation time.
+
+@item max-inline-insns-single
+Several parameters control the tree inliner used in GCC@.
+This number sets the maximum number of instructions (counted in GCC's
+internal representation) in a single function that the tree inliner
+considers for inlining.  This only affects functions declared
+inline and methods implemented in a class declaration (C++).
+The default value is 400.
+
+@item max-inline-insns-auto
+When you use @option{-finline-functions} (included in @option{-O3}),
+a lot of functions that would otherwise not be considered for inlining
+by the compiler are investigated.  To those functions, a different
+(more restrictive) limit compared to functions declared inline can
+be applied.
+The default value is 40.
+
+@item inline-min-speedup
+When estimated performance improvement of caller + callee runtime exceeds this
+threshold (in precent), the function can be inlined regardless the limit on
+@option{--param max-inline-insns-single} and @option{--param
+max-inline-insns-auto}.
+
+@item large-function-insns
+The limit specifying really large functions.  For functions larger than this
+limit after inlining, inlining is constrained by
+@option{--param large-function-growth}.  This parameter is useful primarily
+to avoid extreme compilation time caused by non-linear algorithms used by the
+back end.
+The default value is 2700.
+
+@item large-function-growth
+Specifies maximal growth of large function caused by inlining in percents.
+The default value is 100 which limits large function growth to 2.0 times
+the original size.
+
+@item large-unit-insns
+The limit specifying large translation unit.  Growth caused by inlining of
+units larger than this limit is limited by @option{--param inline-unit-growth}.
+For small units this might be too tight.
+For example, consider a unit consisting of function A
+that is inline and B that just calls A three times.  If B is small relative to
+A, the growth of unit is 300\% and yet such inlining is very sane.  For very
+large units consisting of small inlineable functions, however, the overall unit
+growth limit is needed to avoid exponential explosion of code size.  Thus for
+smaller units, the size is increased to @option{--param large-unit-insns}
+before applying @option{--param inline-unit-growth}.  The default is 10000.
+
+@item inline-unit-growth
+Specifies maximal overall growth of the compilation unit caused by inlining.
+The default value is 30 which limits unit growth to 1.3 times the original
+size.
+
+@item ipcp-unit-growth
+Specifies maximal overall growth of the compilation unit caused by
+interprocedural constant propagation.  The default value is 10 which limits
+unit growth to 1.1 times the original size.
+
+@item large-stack-frame
+The limit specifying large stack frames.  While inlining the algorithm is trying
+to not grow past this limit too much.  The default value is 256 bytes.
+
+@item large-stack-frame-growth
+Specifies maximal growth of large stack frames caused by inlining in percents.
+The default value is 1000 which limits large stack frame growth to 11 times
+the original size.
+
+@item max-inline-insns-recursive
+@itemx max-inline-insns-recursive-auto
+Specifies the maximum number of instructions an out-of-line copy of a
+self-recursive inline
+function can grow into by performing recursive inlining.
+
+For functions declared inline, @option{--param max-inline-insns-recursive} is
+taken into account.  For functions not declared inline, recursive inlining
+happens only when @option{-finline-functions} (included in @option{-O3}) is
+enabled and @option{--param max-inline-insns-recursive-auto} is used.  The
+default value is 450.
+
+@item max-inline-recursive-depth
+@itemx max-inline-recursive-depth-auto
+Specifies the maximum recursion depth used for recursive inlining.
+
+For functions declared inline, @option{--param max-inline-recursive-depth} is
+taken into account.  For functions not declared inline, recursive inlining
+happens only when @option{-finline-functions} (included in @option{-O3}) is
+enabled and @option{--param max-inline-recursive-depth-auto} is used.  The
+default value is 8.
+
+@item min-inline-recursive-probability
+Recursive inlining is profitable only for function having deep recursion
+in average and can hurt for function having little recursion depth by
+increasing the prologue size or complexity of function body to other
+optimizers.
+
+When profile feedback is available (see @option{-fprofile-generate}) the actual
+recursion depth can be guessed from probability that function recurses via a
+given call expression.  This parameter limits inlining only to call expressions
+whose probability exceeds the given threshold (in percents).
+The default value is 10.
+
+@item early-inlining-insns
+Specify growth that the early inliner can make.  In effect it increases
+the amount of inlining for code having a large abstraction penalty.
+The default value is 10.
+
+@item max-early-inliner-iterations
+@itemx max-early-inliner-iterations
+Limit of iterations of the early inliner.  This basically bounds
+the number of nested indirect calls the early inliner can resolve.
+Deeper chains are still handled by late inlining.
+
+@item comdat-sharing-probability
+@itemx comdat-sharing-probability
+Probability (in percent) that C++ inline function with comdat visibility
+are shared across multiple compilation units.  The default value is 20.
+
+@item min-vect-loop-bound
+The minimum number of iterations under which loops are not vectorized
+when @option{-ftree-vectorize} is used.  The number of iterations after
+vectorization needs to be greater than the value specified by this option
+to allow vectorization.  The default value is 0.
+
+@item gcse-cost-distance-ratio
+Scaling factor in calculation of maximum distance an expression
+can be moved by GCSE optimizations.  This is currently supported only in the
+code hoisting pass.  The bigger the ratio, the more aggressive code hoisting
+is with simple expressions, i.e., the expressions that have cost
+less than @option{gcse-unrestricted-cost}.  Specifying 0 disables
+hoisting of simple expressions.  The default value is 10.
+
+@item gcse-unrestricted-cost
+Cost, roughly measured as the cost of a single typical machine
+instruction, at which GCSE optimizations do not constrain
+the distance an expression can travel.  This is currently
+supported only in the code hoisting pass.  The lesser the cost,
+the more aggressive code hoisting is.  Specifying 0 
+allows all expressions to travel unrestricted distances.
+The default value is 3.
+
+@item max-hoist-depth
+The depth of search in the dominator tree for expressions to hoist.
+This is used to avoid quadratic behavior in hoisting algorithm.
+The value of 0 does not limit on the search, but may slow down compilation
+of huge functions.  The default value is 30.
+
+@item max-tail-merge-comparisons
+The maximum amount of similar bbs to compare a bb with.  This is used to
+avoid quadratic behavior in tree tail merging.  The default value is 10.
+
+@item max-tail-merge-iterations
+The maximum amount of iterations of the pass over the function.  This is used to
+limit compilation time in tree tail merging.  The default value is 2.
+
+@item max-unrolled-insns
+The maximum number of instructions that a loop may have to be unrolled.
+If a loop is unrolled, this parameter also determines how many times
+the loop code is unrolled.
+
+@item max-average-unrolled-insns
+The maximum number of instructions biased by probabilities of their execution
+that a loop may have to be unrolled.  If a loop is unrolled,
+this parameter also determines how many times the loop code is unrolled.
+
+@item max-unroll-times
+The maximum number of unrollings of a single loop.
+
+@item max-peeled-insns
+The maximum number of instructions that a loop may have to be peeled.
+If a loop is peeled, this parameter also determines how many times
+the loop code is peeled.
+
+@item max-peel-times
+The maximum number of peelings of a single loop.
+
+@item max-peel-branches
+The maximum number of branches on the hot path through the peeled sequence.
+
+@item max-completely-peeled-insns
+The maximum number of insns of a completely peeled loop.
+
+@item max-completely-peel-times
+The maximum number of iterations of a loop to be suitable for complete peeling.
+
+@item max-completely-peel-loop-nest-depth
+The maximum depth of a loop nest suitable for complete peeling.
+
+@item max-unswitch-insns
+The maximum number of insns of an unswitched loop.
+
+@item max-unswitch-level
+The maximum number of branches unswitched in a single loop.
+
+@item lim-expensive
+The minimum cost of an expensive expression in the loop invariant motion.
+
+@item iv-consider-all-candidates-bound
+Bound on number of candidates for induction variables, below which
+all candidates are considered for each use in induction variable
+optimizations.  If there are more candidates than this,
+only the most relevant ones are considered to avoid quadratic time complexity.
+
+@item iv-max-considered-uses
+The induction variable optimizations give up on loops that contain more
+induction variable uses.
+
+@item iv-always-prune-cand-set-bound
+If the number of candidates in the set is smaller than this value,
+always try to remove unnecessary ivs from the set
+when adding a new one.
+
+@item scev-max-expr-size
+Bound on size of expressions used in the scalar evolutions analyzer.
+Large expressions slow the analyzer.
+
+@item scev-max-expr-complexity
+Bound on the complexity of the expressions in the scalar evolutions analyzer.
+Complex expressions slow the analyzer.
+
+@item omega-max-vars
+The maximum number of variables in an Omega constraint system.
+The default value is 128.
+
+@item omega-max-geqs
+The maximum number of inequalities in an Omega constraint system.
+The default value is 256.
+
+@item omega-max-eqs
+The maximum number of equalities in an Omega constraint system.
+The default value is 128.
+
+@item omega-max-wild-cards
+The maximum number of wildcard variables that the Omega solver is
+able to insert.  The default value is 18.
+
+@item omega-hash-table-size
+The size of the hash table in the Omega solver.  The default value is
+550.
+
+@item omega-max-keys
+The maximal number of keys used by the Omega solver.  The default
+value is 500.
+
+@item omega-eliminate-redundant-constraints
+When set to 1, use expensive methods to eliminate all redundant
+constraints.  The default value is 0.
+
+@item vect-max-version-for-alignment-checks
+The maximum number of run-time checks that can be performed when
+doing loop versioning for alignment in the vectorizer.  See option
+@option{-ftree-vect-loop-version} for more information.
+
+@item vect-max-version-for-alias-checks
+The maximum number of run-time checks that can be performed when
+doing loop versioning for alias in the vectorizer.  See option
+@option{-ftree-vect-loop-version} for more information.
+
+@item max-iterations-to-track
+The maximum number of iterations of a loop the brute-force algorithm
+for analysis of the number of iterations of the loop tries to evaluate.
+
+@item hot-bb-count-ws-permille
+A basic block profile count is considered hot if it contributes to 
+the given permillage (i.e. 0...1000) of the entire profiled execution.
+
+@item hot-bb-frequency-fraction
+Select fraction of the entry block frequency of executions of basic block in
+function given basic block needs to have to be considered hot.
+
+@item max-predicted-iterations
+The maximum number of loop iterations we predict statically.  This is useful
+in cases where a function contains a single loop with known bound and
+another loop with unknown bound.
+The known number of iterations is predicted correctly, while
+the unknown number of iterations average to roughly 10.  This means that the
+loop without bounds appears artificially cold relative to the other one.
+
+@item align-threshold
+
+Select fraction of the maximal frequency of executions of a basic block in
+a function to align the basic block.
+
+@item align-loop-iterations
+
+A loop expected to iterate at least the selected number of iterations is
+aligned.
+
+@item tracer-dynamic-coverage
+@itemx tracer-dynamic-coverage-feedback
+
+This value is used to limit superblock formation once the given percentage of
+executed instructions is covered.  This limits unnecessary code size
+expansion.
+
+The @option{tracer-dynamic-coverage-feedback} is used only when profile
+feedback is available.  The real profiles (as opposed to statically estimated
+ones) are much less balanced allowing the threshold to be larger value.
+
+@item tracer-max-code-growth
+Stop tail duplication once code growth has reached given percentage.  This is
+a rather artificial limit, as most of the duplicates are eliminated later in
+cross jumping, so it may be set to much higher values than is the desired code
+growth.
+
+@item tracer-min-branch-ratio
+
+Stop reverse growth when the reverse probability of best edge is less than this
+threshold (in percent).
+
+@item tracer-min-branch-ratio
+@itemx tracer-min-branch-ratio-feedback
+
+Stop forward growth if the best edge has probability lower than this
+threshold.
+
+Similarly to @option{tracer-dynamic-coverage} two values are present, one for
+compilation for profile feedback and one for compilation without.  The value
+for compilation with profile feedback needs to be more conservative (higher) in
+order to make tracer effective.
+
+@item max-cse-path-length
+
+The maximum number of basic blocks on path that CSE considers.
+The default is 10.
+
+@item max-cse-insns
+The maximum number of instructions CSE processes before flushing.
+The default is 1000.
+
+@item ggc-min-expand
+
+GCC uses a garbage collector to manage its own memory allocation.  This
+parameter specifies the minimum percentage by which the garbage
+collector's heap should be allowed to expand between collections.
+Tuning this may improve compilation speed; it has no effect on code
+generation.
+
+The default is 30% + 70% * (RAM/1GB) with an upper bound of 100% when
+RAM >= 1GB@.  If @code{getrlimit} is available, the notion of ``RAM'' is
+the smallest of actual RAM and @code{RLIMIT_DATA} or @code{RLIMIT_AS}.  If
+GCC is not able to calculate RAM on a particular platform, the lower
+bound of 30% is used.  Setting this parameter and
+@option{ggc-min-heapsize} to zero causes a full collection to occur at
+every opportunity.  This is extremely slow, but can be useful for
+debugging.
+
+@item ggc-min-heapsize
+
+Minimum size of the garbage collector's heap before it begins bothering
+to collect garbage.  The first collection occurs after the heap expands
+by @option{ggc-min-expand}% beyond @option{ggc-min-heapsize}.  Again,
+tuning this may improve compilation speed, and has no effect on code
+generation.
+
+The default is the smaller of RAM/8, RLIMIT_RSS, or a limit that
+tries to ensure that RLIMIT_DATA or RLIMIT_AS are not exceeded, but
+with a lower bound of 4096 (four megabytes) and an upper bound of
+131072 (128 megabytes).  If GCC is not able to calculate RAM on a
+particular platform, the lower bound is used.  Setting this parameter
+very large effectively disables garbage collection.  Setting this
+parameter and @option{ggc-min-expand} to zero causes a full collection
+to occur at every opportunity.
+
+@item max-reload-search-insns
+The maximum number of instruction reload should look backward for equivalent
+register.  Increasing values mean more aggressive optimization, making the
+compilation time increase with probably slightly better performance.
+The default value is 100.
+
+@item max-cselib-memory-locations
+The maximum number of memory locations cselib should take into account.
+Increasing values mean more aggressive optimization, making the compilation time
+increase with probably slightly better performance.  The default value is 500.
+
+@item reorder-blocks-duplicate
+@itemx reorder-blocks-duplicate-feedback
+
+Used by the basic block reordering pass to decide whether to use unconditional
+branch or duplicate the code on its destination.  Code is duplicated when its
+estimated size is smaller than this value multiplied by the estimated size of
+unconditional jump in the hot spots of the program.
+
+The @option{reorder-block-duplicate-feedback} is used only when profile
+feedback is available.  It may be set to higher values than
+@option{reorder-block-duplicate} since information about the hot spots is more
+accurate.
+
+@item max-sched-ready-insns
+The maximum number of instructions ready to be issued the scheduler should
+consider at any given time during the first scheduling pass.  Increasing
+values mean more thorough searches, making the compilation time increase
+with probably little benefit.  The default value is 100.
+
+@item max-sched-region-blocks
+The maximum number of blocks in a region to be considered for
+interblock scheduling.  The default value is 10.
+
+@item max-pipeline-region-blocks
+The maximum number of blocks in a region to be considered for
+pipelining in the selective scheduler.  The default value is 15.
+
+@item max-sched-region-insns
+The maximum number of insns in a region to be considered for
+interblock scheduling.  The default value is 100.
+
+@item max-pipeline-region-insns
+The maximum number of insns in a region to be considered for
+pipelining in the selective scheduler.  The default value is 200.
+
+@item min-spec-prob
+The minimum probability (in percents) of reaching a source block
+for interblock speculative scheduling.  The default value is 40.
+
+@item max-sched-extend-regions-iters
+The maximum number of iterations through CFG to extend regions.
+A value of 0 (the default) disables region extensions.
+
+@item max-sched-insn-conflict-delay
+The maximum conflict delay for an insn to be considered for speculative motion.
+The default value is 3.
+
+@item sched-spec-prob-cutoff
+The minimal probability of speculation success (in percents), so that
+speculative insns are scheduled.
+The default value is 40.
+
+@item sched-spec-state-edge-prob-cutoff
+The minimum probability an edge must have for the scheduler to save its
+state across it.
+The default value is 10.
+
+@item sched-mem-true-dep-cost
+Minimal distance (in CPU cycles) between store and load targeting same
+memory locations.  The default value is 1.
+
+@item selsched-max-lookahead
+The maximum size of the lookahead window of selective scheduling.  It is a
+depth of search for available instructions.
+The default value is 50.
+
+@item selsched-max-sched-times
+The maximum number of times that an instruction is scheduled during
+selective scheduling.  This is the limit on the number of iterations
+through which the instruction may be pipelined.  The default value is 2.
+
+@item selsched-max-insns-to-rename
+The maximum number of best instructions in the ready list that are considered
+for renaming in the selective scheduler.  The default value is 2.
+
+@item sms-min-sc
+The minimum value of stage count that swing modulo scheduler
+generates.  The default value is 2.
+
+@item max-last-value-rtl
+The maximum size measured as number of RTLs that can be recorded in an expression
+in combiner for a pseudo register as last known value of that register.  The default
+is 10000.
+
+@item integer-share-limit
+Small integer constants can use a shared data structure, reducing the
+compiler's memory usage and increasing its speed.  This sets the maximum
+value of a shared integer constant.  The default value is 256.
+
+@item ssp-buffer-size
+The minimum size of buffers (i.e.@: arrays) that receive stack smashing
+protection when @option{-fstack-protection} is used.
+
+@item max-jump-thread-duplication-stmts
+Maximum number of statements allowed in a block that needs to be
+duplicated when threading jumps.
+
+@item max-fields-for-field-sensitive
+Maximum number of fields in a structure treated in
+a field sensitive manner during pointer analysis.  The default is zero
+for @option{-O0} and @option{-O1},
+and 100 for @option{-Os}, @option{-O2}, and @option{-O3}.
+
+@item prefetch-latency
+Estimate on average number of instructions that are executed before
+prefetch finishes.  The distance prefetched ahead is proportional
+to this constant.  Increasing this number may also lead to less
+streams being prefetched (see @option{simultaneous-prefetches}).
+
+@item simultaneous-prefetches
+Maximum number of prefetches that can run at the same time.
+
+@item l1-cache-line-size
+The size of cache line in L1 cache, in bytes.
+
+@item l1-cache-size
+The size of L1 cache, in kilobytes.
+
+@item l2-cache-size
+The size of L2 cache, in kilobytes.
+
+@item min-insn-to-prefetch-ratio
+The minimum ratio between the number of instructions and the
+number of prefetches to enable prefetching in a loop.
+
+@item prefetch-min-insn-to-mem-ratio
+The minimum ratio between the number of instructions and the
+number of memory references to enable prefetching in a loop.
+
+@item use-canonical-types
+Whether the compiler should use the ``canonical'' type system.  By
+default, this should always be 1, which uses a more efficient internal
+mechanism for comparing types in C++ and Objective-C++.  However, if
+bugs in the canonical type system are causing compilation failures,
+set this value to 0 to disable canonical types.
+
+@item switch-conversion-max-branch-ratio
+Switch initialization conversion refuses to create arrays that are
+bigger than @option{switch-conversion-max-branch-ratio} times the number of
+branches in the switch.
+
+@item max-partial-antic-length
+Maximum length of the partial antic set computed during the tree
+partial redundancy elimination optimization (@option{-ftree-pre}) when
+optimizing at @option{-O3} and above.  For some sorts of source code
+the enhanced partial redundancy elimination optimization can run away,
+consuming all of the memory available on the host machine.  This
+parameter sets a limit on the length of the sets that are computed,
+which prevents the runaway behavior.  Setting a value of 0 for
+this parameter allows an unlimited set length.
+
+@item sccvn-max-scc-size
+Maximum size of a strongly connected component (SCC) during SCCVN
+processing.  If this limit is hit, SCCVN processing for the whole
+function is not done and optimizations depending on it are
+disabled.  The default maximum SCC size is 10000.
+
+@item sccvn-max-alias-queries-per-access
+Maximum number of alias-oracle queries we perform when looking for
+redundancies for loads and stores.  If this limit is hit the search
+is aborted and the load or store is not considered redundant.  The
+number of queries is algorithmically limited to the number of
+stores on all paths from the load to the function entry.
+The default maxmimum number of queries is 1000.
+
+@item ira-max-loops-num
+IRA uses regional register allocation by default.  If a function
+contains more loops than the number given by this parameter, only at most
+the given number of the most frequently-executed loops form regions
+for regional register allocation.  The default value of the
+parameter is 100.
+
+@item ira-max-conflict-table-size 
+Although IRA uses a sophisticated algorithm to compress the conflict
+table, the table can still require excessive amounts of memory for
+huge functions.  If the conflict table for a function could be more
+than the size in MB given by this parameter, the register allocator
+instead uses a faster, simpler, and lower-quality
+algorithm that does not require building a pseudo-register conflict table.  
+The default value of the parameter is 2000.
+
+@item ira-loop-reserved-regs
+IRA can be used to evaluate more accurate register pressure in loops
+for decisions to move loop invariants (see @option{-O3}).  The number
+of available registers reserved for some other purposes is given
+by this parameter.  The default value of the parameter is 2, which is
+the minimal number of registers needed by typical instructions.
+This value is the best found from numerous experiments.
+
+@item loop-invariant-max-bbs-in-loop
+Loop invariant motion can be very expensive, both in compilation time and
+in amount of needed compile-time memory, with very large loops.  Loops
+with more basic blocks than this parameter won't have loop invariant
+motion optimization performed on them.  The default value of the
+parameter is 1000 for @option{-O1} and 10000 for @option{-O2} and above.
+
+@item loop-max-datarefs-for-datadeps
+Building data dapendencies is expensive for very large loops.  This
+parameter limits the number of data references in loops that are
+considered for data dependence analysis.  These large loops are no
+handled by the optimizations using loop data dependencies.
+The default value is 1000.
+
+@item max-vartrack-size
+Sets a maximum number of hash table slots to use during variable
+tracking dataflow analysis of any function.  If this limit is exceeded
+with variable tracking at assignments enabled, analysis for that
+function is retried without it, after removing all debug insns from
+the function.  If the limit is exceeded even without debug insns, var
+tracking analysis is completely disabled for the function.  Setting
+the parameter to zero makes it unlimited.
+
+@item max-vartrack-expr-depth
+Sets a maximum number of recursion levels when attempting to map
+variable names or debug temporaries to value expressions.  This trades
+compilation time for more complete debug information.  If this is set too
+low, value expressions that are available and could be represented in
+debug information may end up not being used; setting this higher may
+enable the compiler to find more complex debug expressions, but compile
+time and memory use may grow.  The default is 12.
+
+@item min-nondebug-insn-uid
+Use uids starting at this parameter for nondebug insns.  The range below
+the parameter is reserved exclusively for debug insns created by
+@option{-fvar-tracking-assignments}, but debug insns may get
+(non-overlapping) uids above it if the reserved range is exhausted.
+
+@item ipa-sra-ptr-growth-factor
+IPA-SRA replaces a pointer to an aggregate with one or more new
+parameters only when their cumulative size is less or equal to
+@option{ipa-sra-ptr-growth-factor} times the size of the original
+pointer parameter.
+
+@item tm-max-aggregate-size
+When making copies of thread-local variables in a transaction, this
+parameter specifies the size in bytes after which variables are
+saved with the logging functions as opposed to save/restore code
+sequence pairs.  This option only applies when using
+@option{-fgnu-tm}.
+
+@item graphite-max-nb-scop-params
+To avoid exponential effects in the Graphite loop transforms, the
+number of parameters in a Static Control Part (SCoP) is bounded.  The
+default value is 10 parameters.  A variable whose value is unknown at
+compilation time and defined outside a SCoP is a parameter of the SCoP.
+
+@item graphite-max-bbs-per-function
+To avoid exponential effects in the detection of SCoPs, the size of
+the functions analyzed by Graphite is bounded.  The default value is
+100 basic blocks.
+
+@item loop-block-tile-size
+Loop blocking or strip mining transforms, enabled with
+@option{-floop-block} or @option{-floop-strip-mine}, strip mine each
+loop in the loop nest by a given number of iterations.  The strip
+length can be changed using the @option{loop-block-tile-size}
+parameter.  The default value is 51 iterations.
+
+@item ipa-cp-value-list-size
+IPA-CP attempts to track all possible values and types passed to a function's
+parameter in order to propagate them and perform devirtualization.
+@option{ipa-cp-value-list-size} is the maximum number of values and types it
+stores per one formal parameter of a function.
+
+@item lto-partitions
+Specify desired number of partitions produced during WHOPR compilation.
+The number of partitions should exceed the number of CPUs used for compilation.
+The default value is 32.
+
+@item lto-minpartition
+Size of minimal partition for WHOPR (in estimated instructions).
+This prevents expenses of splitting very small programs into too many
+partitions.
+
+@item cxx-max-namespaces-for-diagnostic-help
+The maximum number of namespaces to consult for suggestions when C++
+name lookup fails for an identifier.  The default is 1000.
+
+@item sink-frequency-threshold
+The maximum relative execution frequency (in percents) of the target block
+relative to a statement's original block to allow statement sinking of a
+statement.  Larger numbers result in more aggressive statement sinking.
+The default value is 75.  A small positive adjustment is applied for
+statements with memory operands as those are even more profitable so sink.
+
+@item max-stores-to-sink
+The maximum number of conditional stores paires that can be sunk.  Set to 0
+if either vectorization (@option{-ftree-vectorize}) or if-conversion
+(@option{-ftree-loop-if-convert}) is disabled.  The default is 2.
+
+@item allow-load-data-races
+Allow optimizers to introduce new data races on loads.
+Set to 1 to allow, otherwise to 0.  This option is enabled by default
+unless implicitly set by the @option{-fmemory-model=} option.
+
+@item allow-store-data-races
+Allow optimizers to introduce new data races on stores.
+Set to 1 to allow, otherwise to 0.  This option is enabled by default
+unless implicitly set by the @option{-fmemory-model=} option.
+
+@item allow-packed-load-data-races
+Allow optimizers to introduce new data races on packed data loads.
+Set to 1 to allow, otherwise to 0.  This option is enabled by default
+unless implicitly set by the @option{-fmemory-model=} option.
+
+@item allow-packed-store-data-races
+Allow optimizers to introduce new data races on packed data stores.
+Set to 1 to allow, otherwise to 0.  This option is enabled by default
+unless implicitly set by the @option{-fmemory-model=} option.
+
+@item case-values-threshold
+The smallest number of different values for which it is best to use a
+jump-table instead of a tree of conditional branches.  If the value is
+0, use the default for the machine.  The default is 0.
+
+@item tree-reassoc-width
+Set the maximum number of instructions executed in parallel in
+reassociated tree. This parameter overrides target dependent
+heuristics used by default if has non zero value.
+
+@item sched-pressure-algorithm
+Choose between the two available implementations of
+@option{-fsched-pressure}.  Algorithm 1 is the original implementation
+and is the more likely to prevent instructions from being reordered.
+Algorithm 2 was designed to be a compromise between the relatively
+conservative approach taken by algorithm 1 and the rather aggressive
+approach taken by the default scheduler.  It relies more heavily on
+having a regular register file and accurate register pressure classes.
+See @file{haifa-sched.c} in the GCC sources for more details.
+
+The default choice depends on the target.
+
+@item max-slsr-cand-scan
+Set the maximum number of existing candidates that will be considered when
+seeking a basis for a new straight-line strength reduction candidate.
+
+@end table
+@end table
+
+@node Preprocessor Options
+@section Options Controlling the Preprocessor
+@cindex preprocessor options
+@cindex options, preprocessor
+
+These options control the C preprocessor, which is run on each C source
+file before actual compilation.
+
+If you use the @option{-E} option, nothing is done except preprocessing.
+Some of these options make sense only together with @option{-E} because
+they cause the preprocessor output to be unsuitable for actual
+compilation.
+
+@table @gcctabopt
+@item -Wp,@var{option}
+@opindex Wp
+You can use @option{-Wp,@var{option}} to bypass the compiler driver
+and pass @var{option} directly through to the preprocessor.  If
+@var{option} contains commas, it is split into multiple options at the
+commas.  However, many options are modified, translated or interpreted
+by the compiler driver before being passed to the preprocessor, and
+@option{-Wp} forcibly bypasses this phase.  The preprocessor's direct
+interface is undocumented and subject to change, so whenever possible
+you should avoid using @option{-Wp} and let the driver handle the
+options instead.
+
+@item -Xpreprocessor @var{option}
+@opindex Xpreprocessor
+Pass @var{option} as an option to the preprocessor.  You can use this to
+supply system-specific preprocessor options that GCC does not 
+recognize.
+
+If you want to pass an option that takes an argument, you must use
+@option{-Xpreprocessor} twice, once for the option and once for the argument.
+
+@item -no-integrated-cpp
+@opindex no-integrated-cpp
+Perform preprocessing as a separate pass before compilation.
+By default, GCC performs preprocessing as an integrated part of
+input tokenization and parsing.
+If this option is provided, the appropriate language front end
+(@command{cc1}, @command{cc1plus}, or @command{cc1obj} for C, C++,
+and Objective-C, respectively) is instead invoked twice,
+once for preprocessing only and once for actual compilation
+of the preprocessed input.
+This option may be useful in conjunction with the @option{-B} or
+@option{-wrapper} options to specify an alternate preprocessor or
+perform additional processing of the program source between
+normal preprocessing and compilation.
+@end table
+
+@include cppopts.texi
+
+@node Assembler Options
+@section Passing Options to the Assembler
+
+@c prevent bad page break with this line
+You can pass options to the assembler.
+
+@table @gcctabopt
+@item -Wa,@var{option}
+@opindex Wa
+Pass @var{option} as an option to the assembler.  If @var{option}
+contains commas, it is split into multiple options at the commas.
+
+@item -Xassembler @var{option}
+@opindex Xassembler
+Pass @var{option} as an option to the assembler.  You can use this to
+supply system-specific assembler options that GCC does not
+recognize.
+
+If you want to pass an option that takes an argument, you must use
+@option{-Xassembler} twice, once for the option and once for the argument.
+
+@end table
+
+@node Link Options
+@section Options for Linking
+@cindex link options
+@cindex options, linking
+
+These options come into play when the compiler links object files into
+an executable output file.  They are meaningless if the compiler is
+not doing a link step.
+
+@table @gcctabopt
+@cindex file names
+@item @var{object-file-name}
+A file name that does not end in a special recognized suffix is
+considered to name an object file or library.  (Object files are
+distinguished from libraries by the linker according to the file
+contents.)  If linking is done, these object files are used as input
+to the linker.
+
+@item -c
+@itemx -S
+@itemx -E
+@opindex c
+@opindex S
+@opindex E
+If any of these options is used, then the linker is not run, and
+object file names should not be used as arguments.  @xref{Overall
+Options}.
+
+@cindex Libraries
+@item -l@var{library}
+@itemx -l @var{library}
+@opindex l
+Search the library named @var{library} when linking.  (The second
+alternative with the library as a separate argument is only for
+POSIX compliance and is not recommended.)
+
+It makes a difference where in the command you write this option; the
+linker searches and processes libraries and object files in the order they
+are specified.  Thus, @samp{foo.o -lz bar.o} searches library @samp{z}
+after file @file{foo.o} but before @file{bar.o}.  If @file{bar.o} refers
+to functions in @samp{z}, those functions may not be loaded.
+
+The linker searches a standard list of directories for the library,
+which is actually a file named @file{lib@var{library}.a}.  The linker
+then uses this file as if it had been specified precisely by name.
+
+The directories searched include several standard system directories
+plus any that you specify with @option{-L}.
+
+Normally the files found this way are library files---archive files
+whose members are object files.  The linker handles an archive file by
+scanning through it for members which define symbols that have so far
+been referenced but not defined.  But if the file that is found is an
+ordinary object file, it is linked in the usual fashion.  The only
+difference between using an @option{-l} option and specifying a file name
+is that @option{-l} surrounds @var{library} with @samp{lib} and @samp{.a}
+and searches several directories.
+
+@item -lobjc
+@opindex lobjc
+You need this special case of the @option{-l} option in order to
+link an Objective-C or Objective-C++ program.
+
+@item -nostartfiles
+@opindex nostartfiles
+Do not use the standard system startup files when linking.
+The standard system libraries are used normally, unless @option{-nostdlib}
+or @option{-nodefaultlibs} is used.
+
+@item -nodefaultlibs
+@opindex nodefaultlibs
+Do not use the standard system libraries when linking.
+Only the libraries you specify are passed to the linker, and options
+specifying linkage of the system libraries, such as @code{-static-libgcc}
+or @code{-shared-libgcc}, are ignored.  
+The standard startup files are used normally, unless @option{-nostartfiles}
+is used.  
+
+The compiler may generate calls to @code{memcmp},
+@code{memset}, @code{memcpy} and @code{memmove}.
+These entries are usually resolved by entries in
+libc.  These entry points should be supplied through some other
+mechanism when this option is specified.
+
+@item -nostdlib
+@opindex nostdlib
+Do not use the standard system startup files or libraries when linking.
+No startup files and only the libraries you specify are passed to
+the linker, and options specifying linkage of the system libraries, such as
+@code{-static-libgcc} or @code{-shared-libgcc}, are ignored.
+
+The compiler may generate calls to @code{memcmp}, @code{memset},
+@code{memcpy} and @code{memmove}.
+These entries are usually resolved by entries in
+libc.  These entry points should be supplied through some other
+mechanism when this option is specified.
+
+@cindex @option{-lgcc}, use with @option{-nostdlib}
+@cindex @option{-nostdlib} and unresolved references
+@cindex unresolved references and @option{-nostdlib}
+@cindex @option{-lgcc}, use with @option{-nodefaultlibs}
+@cindex @option{-nodefaultlibs} and unresolved references
+@cindex unresolved references and @option{-nodefaultlibs}
+One of the standard libraries bypassed by @option{-nostdlib} and
+@option{-nodefaultlibs} is @file{libgcc.a}, a library of internal subroutines
+which GCC uses to overcome shortcomings of particular machines, or special
+needs for some languages.
+(@xref{Interface,,Interfacing to GCC Output,gccint,GNU Compiler
+Collection (GCC) Internals},
+for more discussion of @file{libgcc.a}.)
+In most cases, you need @file{libgcc.a} even when you want to avoid
+other standard libraries.  In other words, when you specify @option{-nostdlib}
+or @option{-nodefaultlibs} you should usually specify @option{-lgcc} as well.
+This ensures that you have no unresolved references to internal GCC
+library subroutines.
+(An example of such an internal subroutine is @samp{__main}, used to ensure C++
+constructors are called; @pxref{Collect2,,@code{collect2}, gccint,
+GNU Compiler Collection (GCC) Internals}.)
+
+@item -pie
+@opindex pie
+Produce a position independent executable on targets that support it.
+For predictable results, you must also specify the same set of options
+used for compilation (@option{-fpie}, @option{-fPIE},
+or model suboptions) when you specify this linker option.
+
+@item -rdynamic
+@opindex rdynamic
+Pass the flag @option{-export-dynamic} to the ELF linker, on targets
+that support it. This instructs the linker to add all symbols, not
+only used ones, to the dynamic symbol table. This option is needed
+for some uses of @code{dlopen} or to allow obtaining backtraces
+from within a program.
+
+@item -s
+@opindex s
+Remove all symbol table and relocation information from the executable.
+
+@item -static
+@opindex static
+On systems that support dynamic linking, this prevents linking with the shared
+libraries.  On other systems, this option has no effect.
+
+@item -shared
+@opindex shared
+Produce a shared object which can then be linked with other objects to
+form an executable.  Not all systems support this option.  For predictable
+results, you must also specify the same set of options used for compilation
+(@option{-fpic}, @option{-fPIC}, or model suboptions) when
+you specify this linker option.@footnote{On some systems, @samp{gcc -shared}
+needs to build supplementary stub code for constructors to work.  On
+multi-libbed systems, @samp{gcc -shared} must select the correct support
+libraries to link against.  Failing to supply the correct flags may lead
+to subtle defects.  Supplying them in cases where they are not necessary
+is innocuous.}
+
+@item -shared-libgcc
+@itemx -static-libgcc
+@opindex shared-libgcc
+@opindex static-libgcc
+On systems that provide @file{libgcc} as a shared library, these options
+force the use of either the shared or static version, respectively.
+If no shared version of @file{libgcc} was built when the compiler was
+configured, these options have no effect.
+
+There are several situations in which an application should use the
+shared @file{libgcc} instead of the static version.  The most common
+of these is when the application wishes to throw and catch exceptions
+across different shared libraries.  In that case, each of the libraries
+as well as the application itself should use the shared @file{libgcc}.
+
+Therefore, the G++ and GCJ drivers automatically add
+@option{-shared-libgcc} whenever you build a shared library or a main
+executable, because C++ and Java programs typically use exceptions, so
+this is the right thing to do.
+
+If, instead, you use the GCC driver to create shared libraries, you may
+find that they are not always linked with the shared @file{libgcc}.
+If GCC finds, at its configuration time, that you have a non-GNU linker
+or a GNU linker that does not support option @option{--eh-frame-hdr},
+it links the shared version of @file{libgcc} into shared libraries
+by default.  Otherwise, it takes advantage of the linker and optimizes
+away the linking with the shared version of @file{libgcc}, linking with
+the static version of libgcc by default.  This allows exceptions to
+propagate through such shared libraries, without incurring relocation
+costs at library load time.
+
+However, if a library or main executable is supposed to throw or catch
+exceptions, you must link it using the G++ or GCJ driver, as appropriate
+for the languages used in the program, or using the option
+@option{-shared-libgcc}, such that it is linked with the shared
+@file{libgcc}.
+
+@item -static-libasan
+When the @option{-fsanitize=address} option is used to link a program,
+the GCC driver automatically links against @option{libasan}.  If
+@file{libasan} is available as a shared library, and the @option{-static}
+option is not used, then this links against the shared version of
+@file{libasan}.  The @option{-static-libasan} option directs the GCC
+driver to link @file{libasan} statically, without necessarily linking
+other libraries statically.
+
+@item -static-libtsan
+When the @option{-fsanitize=thread} option is used to link a program,
+the GCC driver automatically links against @option{libtsan}.  If
+@file{libtsan} is available as a shared library, and the @option{-static}
+option is not used, then this links against the shared version of
+@file{libtsan}.  The @option{-static-libtsan} option directs the GCC
+driver to link @file{libtsan} statically, without necessarily linking
+other libraries statically.
+
+@item -static-libstdc++
+When the @command{g++} program is used to link a C++ program, it
+normally automatically links against @option{libstdc++}.  If
+@file{libstdc++} is available as a shared library, and the
+@option{-static} option is not used, then this links against the
+shared version of @file{libstdc++}.  That is normally fine.  However, it
+is sometimes useful to freeze the version of @file{libstdc++} used by
+the program without going all the way to a fully static link.  The
+@option{-static-libstdc++} option directs the @command{g++} driver to
+link @file{libstdc++} statically, without necessarily linking other
+libraries statically.
+
+@item -symbolic
+@opindex symbolic
+Bind references to global symbols when building a shared object.  Warn
+about any unresolved references (unless overridden by the link editor
+option @option{-Xlinker -z -Xlinker defs}).  Only a few systems support
+this option.
+
+@item -T @var{script}
+@opindex T
+@cindex linker script
+Use @var{script} as the linker script.  This option is supported by most
+systems using the GNU linker.  On some targets, such as bare-board
+targets without an operating system, the @option{-T} option may be required
+when linking to avoid references to undefined symbols.
+
+@item -Xlinker @var{option}
+@opindex Xlinker
+Pass @var{option} as an option to the linker.  You can use this to
+supply system-specific linker options that GCC does not recognize.
+
+If you want to pass an option that takes a separate argument, you must use
+@option{-Xlinker} twice, once for the option and once for the argument.
+For example, to pass @option{-assert definitions}, you must write
+@option{-Xlinker -assert -Xlinker definitions}.  It does not work to write
+@option{-Xlinker "-assert definitions"}, because this passes the entire
+string as a single argument, which is not what the linker expects.
+
+When using the GNU linker, it is usually more convenient to pass
+arguments to linker options using the @option{@var{option}=@var{value}}
+syntax than as separate arguments.  For example, you can specify
+@option{-Xlinker -Map=output.map} rather than
+@option{-Xlinker -Map -Xlinker output.map}.  Other linkers may not support
+this syntax for command-line options.
+
+@item -Wl,@var{option}
+@opindex Wl
+Pass @var{option} as an option to the linker.  If @var{option} contains
+commas, it is split into multiple options at the commas.  You can use this
+syntax to pass an argument to the option.
+For example, @option{-Wl,-Map,output.map} passes @option{-Map output.map} to the
+linker.  When using the GNU linker, you can also get the same effect with
+@option{-Wl,-Map=output.map}.
+
+@item -u @var{symbol}
+@opindex u
+Pretend the symbol @var{symbol} is undefined, to force linking of
+library modules to define it.  You can use @option{-u} multiple times with
+different symbols to force loading of additional library modules.
+@end table
+
+@node Directory Options
+@section Options for Directory Search
+@cindex directory options
+@cindex options, directory search
+@cindex search path
+
+These options specify directories to search for header files, for
+libraries and for parts of the compiler:
+
+@table @gcctabopt
+@item -I@var{dir}
+@opindex I
+Add the directory @var{dir} to the head of the list of directories to be
+searched for header files.  This can be used to override a system header
+file, substituting your own version, since these directories are
+searched before the system header file directories.  However, you should
+not use this option to add directories that contain vendor-supplied
+system header files (use @option{-isystem} for that).  If you use more than
+one @option{-I} option, the directories are scanned in left-to-right
+order; the standard system directories come after.
+
+If a standard system include directory, or a directory specified with
+@option{-isystem}, is also specified with @option{-I}, the @option{-I}
+option is ignored.  The directory is still searched but as a
+system directory at its normal position in the system include chain.
+This is to ensure that GCC's procedure to fix buggy system headers and
+the ordering for the @code{include_next} directive are not inadvertently changed.
+If you really need to change the search order for system directories,
+use the @option{-nostdinc} and/or @option{-isystem} options.
+
+@item -iplugindir=@var{dir}
+Set the directory to search for plugins that are passed
+by @option{-fplugin=@var{name}} instead of
+@option{-fplugin=@var{path}/@var{name}.so}.  This option is not meant
+to be used by the user, but only passed by the driver.
+
+@item -iquote@var{dir}
+@opindex iquote
+Add the directory @var{dir} to the head of the list of directories to
+be searched for header files only for the case of @samp{#include
+"@var{file}"}; they are not searched for @samp{#include <@var{file}>},
+otherwise just like @option{-I}.
+
+@item -L@var{dir}
+@opindex L
+Add directory @var{dir} to the list of directories to be searched
+for @option{-l}.
+
+@item -B@var{prefix}
+@opindex B
+This option specifies where to find the executables, libraries,
+include files, and data files of the compiler itself.
+
+The compiler driver program runs one or more of the subprograms
+@command{cpp}, @command{cc1}, @command{as} and @command{ld}.  It tries
+@var{prefix} as a prefix for each program it tries to run, both with and
+without @samp{@var{machine}/@var{version}/} (@pxref{Target Options}).
+
+For each subprogram to be run, the compiler driver first tries the
+@option{-B} prefix, if any.  If that name is not found, or if @option{-B}
+is not specified, the driver tries two standard prefixes, 
+@file{/usr/lib/gcc/} and @file{/usr/local/lib/gcc/}.  If neither of
+those results in a file name that is found, the unmodified program
+name is searched for using the directories specified in your
+@env{PATH} environment variable.
+
+The compiler checks to see if the path provided by the @option{-B}
+refers to a directory, and if necessary it adds a directory
+separator character at the end of the path.
+
+@option{-B} prefixes that effectively specify directory names also apply
+to libraries in the linker, because the compiler translates these
+options into @option{-L} options for the linker.  They also apply to
+includes files in the preprocessor, because the compiler translates these
+options into @option{-isystem} options for the preprocessor.  In this case,
+the compiler appends @samp{include} to the prefix.
+
+The runtime support file @file{libgcc.a} can also be searched for using
+the @option{-B} prefix, if needed.  If it is not found there, the two
+standard prefixes above are tried, and that is all.  The file is left
+out of the link if it is not found by those means.
+
+Another way to specify a prefix much like the @option{-B} prefix is to use
+the environment variable @env{GCC_EXEC_PREFIX}.  @xref{Environment
+Variables}.
+
+As a special kludge, if the path provided by @option{-B} is
+@file{[dir/]stage@var{N}/}, where @var{N} is a number in the range 0 to
+9, then it is replaced by @file{[dir/]include}.  This is to help
+with boot-strapping the compiler.
+
+@item -specs=@var{file}
+@opindex specs
+Process @var{file} after the compiler reads in the standard @file{specs}
+file, in order to override the defaults which the @command{gcc} driver
+program uses when determining what switches to pass to @command{cc1},
+@command{cc1plus}, @command{as}, @command{ld}, etc.  More than one
+@option{-specs=@var{file}} can be specified on the command line, and they
+are processed in order, from left to right.
+
+@item --sysroot=@var{dir}
+@opindex sysroot
+Use @var{dir} as the logical root directory for headers and libraries.
+For example, if the compiler normally searches for headers in
+@file{/usr/include} and libraries in @file{/usr/lib}, it instead
+searches @file{@var{dir}/usr/include} and @file{@var{dir}/usr/lib}.
+
+If you use both this option and the @option{-isysroot} option, then
+the @option{--sysroot} option applies to libraries, but the
+@option{-isysroot} option applies to header files.
+
+The GNU linker (beginning with version 2.16) has the necessary support
+for this option.  If your linker does not support this option, the
+header file aspect of @option{--sysroot} still works, but the
+library aspect does not.
+
+@item --no-sysroot-suffix
+@opindex no-sysroot-suffix
+For some targets, a suffix is added to the root directory specified
+with @option{--sysroot}, depending on the other options used, so that
+headers may for example be found in
+@file{@var{dir}/@var{suffix}/usr/include} instead of
+@file{@var{dir}/usr/include}.  This option disables the addition of
+such a suffix.
+
+@item -I-
+@opindex I-
+This option has been deprecated.  Please use @option{-iquote} instead for
+@option{-I} directories before the @option{-I-} and remove the @option{-I-}.
+Any directories you specify with @option{-I} options before the @option{-I-}
+option are searched only for the case of @samp{#include "@var{file}"};
+they are not searched for @samp{#include <@var{file}>}.
+
+If additional directories are specified with @option{-I} options after
+the @option{-I-}, these directories are searched for all @samp{#include}
+directives.  (Ordinarily @emph{all} @option{-I} directories are used
+this way.)
+
+In addition, the @option{-I-} option inhibits the use of the current
+directory (where the current input file came from) as the first search
+directory for @samp{#include "@var{file}"}.  There is no way to
+override this effect of @option{-I-}.  With @option{-I.} you can specify
+searching the directory that is current when the compiler is
+invoked.  That is not exactly the same as what the preprocessor does
+by default, but it is often satisfactory.
+
+@option{-I-} does not inhibit the use of the standard system directories
+for header files.  Thus, @option{-I-} and @option{-nostdinc} are
+independent.
+@end table
+
+@c man end
+
+@node Spec Files
+@section Specifying subprocesses and the switches to pass to them
+@cindex Spec Files
+
+@command{gcc} is a driver program.  It performs its job by invoking a
+sequence of other programs to do the work of compiling, assembling and
+linking.  GCC interprets its command-line parameters and uses these to
+deduce which programs it should invoke, and which command-line options
+it ought to place on their command lines.  This behavior is controlled
+by @dfn{spec strings}.  In most cases there is one spec string for each
+program that GCC can invoke, but a few programs have multiple spec
+strings to control their behavior.  The spec strings built into GCC can
+be overridden by using the @option{-specs=} command-line switch to specify
+a spec file.
+
+@dfn{Spec files} are plaintext files that are used to construct spec
+strings.  They consist of a sequence of directives separated by blank
+lines.  The type of directive is determined by the first non-whitespace
+character on the line, which can be one of the following:
+
+@table @code
+@item %@var{command}
+Issues a @var{command} to the spec file processor.  The commands that can
+appear here are:
+
+@table @code
+@item %include <@var{file}>
+@cindex @code{%include}
+Search for @var{file} and insert its text at the current point in the
+specs file.
+
+@item %include_noerr <@var{file}>
+@cindex @code{%include_noerr}
+Just like @samp{%include}, but do not generate an error message if the include
+file cannot be found.
+
+@item %rename @var{old_name} @var{new_name}
+@cindex @code{%rename}
+Rename the spec string @var{old_name} to @var{new_name}.
+
+@end table
+
+@item *[@var{spec_name}]:
+This tells the compiler to create, override or delete the named spec
+string.  All lines after this directive up to the next directive or
+blank line are considered to be the text for the spec string.  If this
+results in an empty string then the spec is deleted.  (Or, if the
+spec did not exist, then nothing happens.)  Otherwise, if the spec
+does not currently exist a new spec is created.  If the spec does
+exist then its contents are overridden by the text of this
+directive, unless the first character of that text is the @samp{+}
+character, in which case the text is appended to the spec.
+
+@item [@var{suffix}]:
+Creates a new @samp{[@var{suffix}] spec} pair.  All lines after this directive
+and up to the next directive or blank line are considered to make up the
+spec string for the indicated suffix.  When the compiler encounters an
+input file with the named suffix, it processes the spec string in
+order to work out how to compile that file.  For example:
+
+@smallexample
+.ZZ:
+z-compile -input %i
+@end smallexample
+
+This says that any input file whose name ends in @samp{.ZZ} should be
+passed to the program @samp{z-compile}, which should be invoked with the
+command-line switch @option{-input} and with the result of performing the
+@samp{%i} substitution.  (See below.)
+
+As an alternative to providing a spec string, the text following a
+suffix directive can be one of the following:
+
+@table @code
+@item @@@var{language}
+This says that the suffix is an alias for a known @var{language}.  This is
+similar to using the @option{-x} command-line switch to GCC to specify a
+language explicitly.  For example:
+
+@smallexample
+.ZZ:
+@@c++
+@end smallexample
+
+Says that .ZZ files are, in fact, C++ source files.
+
+@item #@var{name}
+This causes an error messages saying:
+
+@smallexample
+@var{name} compiler not installed on this system.
+@end smallexample
+@end table
+
+GCC already has an extensive list of suffixes built into it.
+This directive adds an entry to the end of the list of suffixes, but
+since the list is searched from the end backwards, it is effectively
+possible to override earlier entries using this technique.
+
+@end table
+
+GCC has the following spec strings built into it.  Spec files can
+override these strings or create their own.  Note that individual
+targets can also add their own spec strings to this list.
+
+@smallexample
+asm          Options to pass to the assembler
+asm_final    Options to pass to the assembler post-processor
+cpp          Options to pass to the C preprocessor
+cc1          Options to pass to the C compiler
+cc1plus      Options to pass to the C++ compiler
+endfile      Object files to include at the end of the link
+link         Options to pass to the linker
+lib          Libraries to include on the command line to the linker
+libgcc       Decides which GCC support library to pass to the linker
+linker       Sets the name of the linker
+predefines   Defines to be passed to the C preprocessor
+signed_char  Defines to pass to CPP to say whether @code{char} is signed
+             by default
+startfile    Object files to include at the start of the link
+@end smallexample
+
+Here is a small example of a spec file:
+
+@smallexample
+%rename lib                 old_lib
+
+*lib:
+--start-group -lgcc -lc -leval1 --end-group %(old_lib)
+@end smallexample
+
+This example renames the spec called @samp{lib} to @samp{old_lib} and
+then overrides the previous definition of @samp{lib} with a new one.
+The new definition adds in some extra command-line options before
+including the text of the old definition.
+
+@dfn{Spec strings} are a list of command-line options to be passed to their
+corresponding program.  In addition, the spec strings can contain
+@samp{%}-prefixed sequences to substitute variable text or to
+conditionally insert text into the command line.  Using these constructs
+it is possible to generate quite complex command lines.
+
+Here is a table of all defined @samp{%}-sequences for spec
+strings.  Note that spaces are not generated automatically around the
+results of expanding these sequences.  Therefore you can concatenate them
+together or combine them with constant text in a single argument.
+
+@table @code
+@item %%
+Substitute one @samp{%} into the program name or argument.
+
+@item %i
+Substitute the name of the input file being processed.
+
+@item %b
+Substitute the basename of the input file being processed.
+This is the substring up to (and not including) the last period
+and not including the directory.
+
+@item %B
+This is the same as @samp{%b}, but include the file suffix (text after
+the last period).
+
+@item %d
+Marks the argument containing or following the @samp{%d} as a
+temporary file name, so that that file is deleted if GCC exits
+successfully.  Unlike @samp{%g}, this contributes no text to the
+argument.
+
+@item %g@var{suffix}
+Substitute a file name that has suffix @var{suffix} and is chosen
+once per compilation, and mark the argument in the same way as
+@samp{%d}.  To reduce exposure to denial-of-service attacks, the file
+name is now chosen in a way that is hard to predict even when previously
+chosen file names are known.  For example, @samp{%g.s @dots{} %g.o @dots{} %g.s}
+might turn into @samp{ccUVUUAU.s ccXYAXZ12.o ccUVUUAU.s}.  @var{suffix} matches
+the regexp @samp{[.A-Za-z]*} or the special string @samp{%O}, which is
+treated exactly as if @samp{%O} had been preprocessed.  Previously, @samp{%g}
+was simply substituted with a file name chosen once per compilation,
+without regard to any appended suffix (which was therefore treated
+just like ordinary text), making such attacks more likely to succeed.
+
+@item %u@var{suffix}
+Like @samp{%g}, but generates a new temporary file name
+each time it appears instead of once per compilation.
+
+@item %U@var{suffix}
+Substitutes the last file name generated with @samp{%u@var{suffix}}, generating a
+new one if there is no such last file name.  In the absence of any
+@samp{%u@var{suffix}}, this is just like @samp{%g@var{suffix}}, except they don't share
+the same suffix @emph{space}, so @samp{%g.s @dots{} %U.s @dots{} %g.s @dots{} %U.s}
+involves the generation of two distinct file names, one
+for each @samp{%g.s} and another for each @samp{%U.s}.  Previously, @samp{%U} was
+simply substituted with a file name chosen for the previous @samp{%u},
+without regard to any appended suffix.
+
+@item %j@var{suffix}
+Substitutes the name of the @code{HOST_BIT_BUCKET}, if any, and if it is
+writable, and if @option{-save-temps} is not used; 
+otherwise, substitute the name
+of a temporary file, just like @samp{%u}.  This temporary file is not
+meant for communication between processes, but rather as a junk
+disposal mechanism.
+
+@item %|@var{suffix}
+@itemx %m@var{suffix}
+Like @samp{%g}, except if @option{-pipe} is in effect.  In that case
+@samp{%|} substitutes a single dash and @samp{%m} substitutes nothing at
+all.  These are the two most common ways to instruct a program that it
+should read from standard input or write to standard output.  If you
+need something more elaborate you can use an @samp{%@{pipe:@code{X}@}}
+construct: see for example @file{f/lang-specs.h}.
+
+@item %.@var{SUFFIX}
+Substitutes @var{.SUFFIX} for the suffixes of a matched switch's args
+when it is subsequently output with @samp{%*}.  @var{SUFFIX} is
+terminated by the next space or %.
+
+@item %w
+Marks the argument containing or following the @samp{%w} as the
+designated output file of this compilation.  This puts the argument
+into the sequence of arguments that @samp{%o} substitutes.
+
+@item %o
+Substitutes the names of all the output files, with spaces
+automatically placed around them.  You should write spaces
+around the @samp{%o} as well or the results are undefined.
+@samp{%o} is for use in the specs for running the linker.
+Input files whose names have no recognized suffix are not compiled
+at all, but they are included among the output files, so they are
+linked.
+
+@item %O
+Substitutes the suffix for object files.  Note that this is
+handled specially when it immediately follows @samp{%g, %u, or %U},
+because of the need for those to form complete file names.  The
+handling is such that @samp{%O} is treated exactly as if it had already
+been substituted, except that @samp{%g, %u, and %U} do not currently
+support additional @var{suffix} characters following @samp{%O} as they do
+following, for example, @samp{.o}.
+
+@item %p
+Substitutes the standard macro predefinitions for the
+current target machine.  Use this when running @code{cpp}.
+
+@item %P
+Like @samp{%p}, but puts @samp{__} before and after the name of each
+predefined macro, except for macros that start with @samp{__} or with
+@samp{_@var{L}}, where @var{L} is an uppercase letter.  This is for ISO
+C@.
+
+@item %I
+Substitute any of @option{-iprefix} (made from @env{GCC_EXEC_PREFIX}),
+@option{-isysroot} (made from @env{TARGET_SYSTEM_ROOT}),
+@option{-isystem} (made from @env{COMPILER_PATH} and @option{-B} options)
+and @option{-imultilib} as necessary.
+
+@item %s
+Current argument is the name of a library or startup file of some sort.
+Search for that file in a standard list of directories and substitute
+the full name found.  The current working directory is included in the
+list of directories scanned.
+
+@item %T
+Current argument is the name of a linker script.  Search for that file
+in the current list of directories to scan for libraries. If the file
+is located insert a @option{--script} option into the command line
+followed by the full path name found.  If the file is not found then
+generate an error message.  Note: the current working directory is not
+searched.
+
+@item %e@var{str}
+Print @var{str} as an error message.  @var{str} is terminated by a newline.
+Use this when inconsistent options are detected.
+
+@item %(@var{name})
+Substitute the contents of spec string @var{name} at this point.
+
+@item %x@{@var{option}@}
+Accumulate an option for @samp{%X}.
+
+@item %X
+Output the accumulated linker options specified by @option{-Wl} or a @samp{%x}
+spec string.
+
+@item %Y
+Output the accumulated assembler options specified by @option{-Wa}.
+
+@item %Z
+Output the accumulated preprocessor options specified by @option{-Wp}.
+
+@item %a
+Process the @code{asm} spec.  This is used to compute the
+switches to be passed to the assembler.
+
+@item %A
+Process the @code{asm_final} spec.  This is a spec string for
+passing switches to an assembler post-processor, if such a program is
+needed.
+
+@item %l
+Process the @code{link} spec.  This is the spec for computing the
+command line passed to the linker.  Typically it makes use of the
+@samp{%L %G %S %D and %E} sequences.
+
+@item %D
+Dump out a @option{-L} option for each directory that GCC believes might
+contain startup files.  If the target supports multilibs then the
+current multilib directory is prepended to each of these paths.
+
+@item %L
+Process the @code{lib} spec.  This is a spec string for deciding which
+libraries are included on the command line to the linker.
+
+@item %G
+Process the @code{libgcc} spec.  This is a spec string for deciding
+which GCC support library is included on the command line to the linker.
+
+@item %S
+Process the @code{startfile} spec.  This is a spec for deciding which
+object files are the first ones passed to the linker.  Typically
+this might be a file named @file{crt0.o}.
+
+@item %E
+Process the @code{endfile} spec.  This is a spec string that specifies
+the last object files that are passed to the linker.
+
+@item %C
+Process the @code{cpp} spec.  This is used to construct the arguments
+to be passed to the C preprocessor.
+
+@item %1
+Process the @code{cc1} spec.  This is used to construct the options to be
+passed to the actual C compiler (@samp{cc1}).
+
+@item %2
+Process the @code{cc1plus} spec.  This is used to construct the options to be
+passed to the actual C++ compiler (@samp{cc1plus}).
+
+@item %*
+Substitute the variable part of a matched option.  See below.
+Note that each comma in the substituted string is replaced by
+a single space.
+
+@item %<@code{S}
+Remove all occurrences of @code{-S} from the command line.  Note---this
+command is position dependent.  @samp{%} commands in the spec string
+before this one see @code{-S}, @samp{%} commands in the spec string
+after this one do not.
+
+@item %:@var{function}(@var{args})
+Call the named function @var{function}, passing it @var{args}.
+@var{args} is first processed as a nested spec string, then split
+into an argument vector in the usual fashion.  The function returns
+a string which is processed as if it had appeared literally as part
+of the current spec.
+
+The following built-in spec functions are provided:
+
+@table @code
+@item @code{getenv}
+The @code{getenv} spec function takes two arguments: an environment
+variable name and a string.  If the environment variable is not
+defined, a fatal error is issued.  Otherwise, the return value is the
+value of the environment variable concatenated with the string.  For
+example, if @env{TOPDIR} is defined as @file{/path/to/top}, then:
+
+@smallexample
+%:getenv(TOPDIR /include)
+@end smallexample
+
+expands to @file{/path/to/top/include}.
+
+@item @code{if-exists}
+The @code{if-exists} spec function takes one argument, an absolute
+pathname to a file.  If the file exists, @code{if-exists} returns the
+pathname.  Here is a small example of its usage:
+
+@smallexample
+*startfile:
+crt0%O%s %:if-exists(crti%O%s) crtbegin%O%s
+@end smallexample
+
+@item @code{if-exists-else}
+The @code{if-exists-else} spec function is similar to the @code{if-exists}
+spec function, except that it takes two arguments.  The first argument is
+an absolute pathname to a file.  If the file exists, @code{if-exists-else}
+returns the pathname.  If it does not exist, it returns the second argument.
+This way, @code{if-exists-else} can be used to select one file or another,
+based on the existence of the first.  Here is a small example of its usage:
+
+@smallexample
+*startfile:
+crt0%O%s %:if-exists(crti%O%s) \
+%:if-exists-else(crtbeginT%O%s crtbegin%O%s)
+@end smallexample
+
+@item @code{replace-outfile}
+The @code{replace-outfile} spec function takes two arguments.  It looks for the
+first argument in the outfiles array and replaces it with the second argument.  Here
+is a small example of its usage:
+
+@smallexample
+%@{fgnu-runtime:%:replace-outfile(-lobjc -lobjc-gnu)@}
+@end smallexample
+
+@item @code{remove-outfile}
+The @code{remove-outfile} spec function takes one argument.  It looks for the
+first argument in the outfiles array and removes it.  Here is a small example
+its usage:
+
+@smallexample
+%:remove-outfile(-lm)
+@end smallexample
+
+@item @code{pass-through-libs}
+The @code{pass-through-libs} spec function takes any number of arguments.  It
+finds any @option{-l} options and any non-options ending in @file{.a} (which it
+assumes are the names of linker input library archive files) and returns a
+result containing all the found arguments each prepended by
+@option{-plugin-opt=-pass-through=} and joined by spaces.  This list is
+intended to be passed to the LTO linker plugin.
+
+@smallexample
+%:pass-through-libs(%G %L %G)
+@end smallexample
+
+@item @code{print-asm-header}
+The @code{print-asm-header} function takes no arguments and simply
+prints a banner like:
+
+@smallexample
+Assembler options
+=================
+
+Use "-Wa,OPTION" to pass "OPTION" to the assembler.
+@end smallexample
+
+It is used to separate compiler options from assembler options
+in the @option{--target-help} output.
+@end table
+
+@item %@{@code{S}@}
+Substitutes the @code{-S} switch, if that switch is given to GCC@.
+If that switch is not specified, this substitutes nothing.  Note that
+the leading dash is omitted when specifying this option, and it is
+automatically inserted if the substitution is performed.  Thus the spec
+string @samp{%@{foo@}} matches the command-line option @option{-foo}
+and outputs the command-line option @option{-foo}.
+
+@item %W@{@code{S}@}
+Like %@{@code{S}@} but mark last argument supplied within as a file to be
+deleted on failure.
+
+@item %@{@code{S}*@}
+Substitutes all the switches specified to GCC whose names start
+with @code{-S}, but which also take an argument.  This is used for
+switches like @option{-o}, @option{-D}, @option{-I}, etc.
+GCC considers @option{-o foo} as being
+one switch whose name starts with @samp{o}.  %@{o*@} substitutes this
+text, including the space.  Thus two arguments are generated.
+
+@item %@{@code{S}*&@code{T}*@}
+Like %@{@code{S}*@}, but preserve order of @code{S} and @code{T} options
+(the order of @code{S} and @code{T} in the spec is not significant).
+There can be any number of ampersand-separated variables; for each the
+wild card is optional.  Useful for CPP as @samp{%@{D*&U*&A*@}}.
+
+@item %@{@code{S}:@code{X}@}
+Substitutes @code{X}, if the @option{-S} switch is given to GCC@.
+
+@item %@{!@code{S}:@code{X}@}
+Substitutes @code{X}, if the @option{-S} switch is @emph{not} given to GCC@.
+
+@item %@{@code{S}*:@code{X}@}
+Substitutes @code{X} if one or more switches whose names start with
+@code{-S} are specified to GCC@.  Normally @code{X} is substituted only
+once, no matter how many such switches appeared.  However, if @code{%*}
+appears somewhere in @code{X}, then @code{X} is substituted once
+for each matching switch, with the @code{%*} replaced by the part of
+that switch matching the @code{*}.
+
+@item %@{.@code{S}:@code{X}@}
+Substitutes @code{X}, if processing a file with suffix @code{S}.
+
+@item %@{!.@code{S}:@code{X}@}
+Substitutes @code{X}, if @emph{not} processing a file with suffix @code{S}.
+
+@item %@{,@code{S}:@code{X}@}
+Substitutes @code{X}, if processing a file for language @code{S}.
+
+@item %@{!,@code{S}:@code{X}@}
+Substitutes @code{X}, if not processing a file for language @code{S}.
+
+@item %@{@code{S}|@code{P}:@code{X}@}
+Substitutes @code{X} if either @code{-S} or @code{-P} is given to
+GCC@.  This may be combined with @samp{!}, @samp{.}, @samp{,}, and
+@code{*} sequences as well, although they have a stronger binding than
+the @samp{|}.  If @code{%*} appears in @code{X}, all of the
+alternatives must be starred, and only the first matching alternative
+is substituted.
+
+For example, a spec string like this:
+
+@smallexample
+%@{.c:-foo@} %@{!.c:-bar@} %@{.c|d:-baz@} %@{!.c|d:-boggle@}
+@end smallexample
+
+@noindent
+outputs the following command-line options from the following input
+command-line options:
+
+@smallexample
+fred.c        -foo -baz
+jim.d         -bar -boggle
+-d fred.c     -foo -baz -boggle
+-d jim.d      -bar -baz -boggle
+@end smallexample
+
+@item %@{S:X; T:Y; :D@}
+
+If @code{S} is given to GCC, substitutes @code{X}; else if @code{T} is
+given to GCC, substitutes @code{Y}; else substitutes @code{D}.  There can
+be as many clauses as you need.  This may be combined with @code{.},
+@code{,}, @code{!}, @code{|}, and @code{*} as needed.
+
+
+@end table
+
+The conditional text @code{X} in a %@{@code{S}:@code{X}@} or similar
+construct may contain other nested @samp{%} constructs or spaces, or
+even newlines.  They are processed as usual, as described above.
+Trailing white space in @code{X} is ignored.  White space may also
+appear anywhere on the left side of the colon in these constructs,
+except between @code{.} or @code{*} and the corresponding word.
+
+The @option{-O}, @option{-f}, @option{-m}, and @option{-W} switches are
+handled specifically in these constructs.  If another value of
+@option{-O} or the negated form of a @option{-f}, @option{-m}, or
+@option{-W} switch is found later in the command line, the earlier
+switch value is ignored, except with @{@code{S}*@} where @code{S} is
+just one letter, which passes all matching options.
+
+The character @samp{|} at the beginning of the predicate text is used to
+indicate that a command should be piped to the following command, but
+only if @option{-pipe} is specified.
+
+It is built into GCC which switches take arguments and which do not.
+(You might think it would be useful to generalize this to allow each
+compiler's spec to say which switches take arguments.  But this cannot
+be done in a consistent fashion.  GCC cannot even decide which input
+files have been specified without knowing which switches take arguments,
+and it must know which input files to compile in order to tell which
+compilers to run).
+
+GCC also knows implicitly that arguments starting in @option{-l} are to be
+treated as compiler output files, and passed to the linker in their
+proper position among the other output files.
+
+@c man begin OPTIONS
+
+@node Target Options
+@section Specifying Target Machine and Compiler Version
+@cindex target options
+@cindex cross compiling
+@cindex specifying machine version
+@cindex specifying compiler version and target machine
+@cindex compiler version, specifying
+@cindex target machine, specifying
+
+The usual way to run GCC is to run the executable called @command{gcc}, or
+@command{@var{machine}-gcc} when cross-compiling, or
+@command{@var{machine}-gcc-@var{version}} to run a version other than the
+one that was installed last.
+
+@node Submodel Options
+@section Hardware Models and Configurations
+@cindex submodel options
+@cindex specifying hardware config
+@cindex hardware models and configurations, specifying
+@cindex machine dependent options
+
+Each target machine types can have its own
+special options, starting with @samp{-m}, to choose among various
+hardware models or configurations---for example, 68010 vs 68020,
+floating coprocessor or none.  A single installed version of the
+compiler can compile for any model or configuration, according to the
+options specified.
+
+Some configurations of the compiler also support additional special
+options, usually for compatibility with other compilers on the same
+platform.
+
+@c This list is ordered alphanumerically by subsection name.
+@c It should be the same order and spelling as these options are listed
+@c in Machine Dependent Options
+
+@menu
+* AArch64 Options::
+* Adapteva Epiphany Options::
+* ARM Options::
+* AVR Options::
+* Blackfin Options::
+* C6X Options::
+* CRIS Options::
+* CR16 Options::
+* Darwin Options::
+* DEC Alpha Options::
+* FR30 Options::
+* FRV Options::
+* GNU/Linux Options::
+* H8/300 Options::
+* HPPA Options::
+* i386 and x86-64 Options::
+* i386 and x86-64 Windows Options::
+* IA-64 Options::
+* LM32 Options::
+* M32C Options::
+* M32R/D Options::
+* M680x0 Options::
+* MCore Options::
+* MeP Options::
+* MicroBlaze Options::
+* MIPS Options::
+* MMIX Options::
+* MN10300 Options::
+* Moxie Options::
+* PDP-11 Options::
+* picoChip Options::
+* PowerPC Options::
+* RL78 Options::
+* RS/6000 and PowerPC Options::
+* RX Options::
+* S/390 and zSeries Options::
+* Score Options::
+* SH Options::
+* Solaris 2 Options::
+* SPARC Options::
+* SPU Options::
+* System V Options::
+* TILE-Gx Options::
+* TILEPro Options::
+* V850 Options::
+* VAX Options::
+* VMS Options::
+* VxWorks Options::
+* x86-64 Options::
+* Xstormy16 Options::
+* Xtensa Options::
+* zSeries Options::
+@end menu
+
+@node AArch64 Options
+@subsection AArch64 Options
+@cindex AArch64 Options
+
+These options are defined for AArch64 implementations:
+
+@table @gcctabopt
+
+@item -mbig-endian
+@opindex mbig-endian
+Generate big-endian code.  This is the default when GCC is configured for an
+@samp{aarch64_be-*-*} target.
+
+@item -mgeneral-regs-only
+@opindex mgeneral-regs-only
+Generate code which uses only the general registers.
+
+@item -mlittle-endian
+@opindex mlittle-endian
+Generate little-endian code.  This is the default when GCC is configured for an
+@samp{aarch64-*-*} but not an @samp{aarch64_be-*-*} target.
+
+@item -mcmodel=tiny
+@opindex mcmodel=tiny
+Generate code for the tiny code model.  The program and its statically defined
+symbols must be within 1GB of each other.  Pointers are 64 bits.  Programs can
+be statically or dynamically linked.  This model is not fully implemented and
+mostly treated as @samp{small}.
+
+@item -mcmodel=small
+@opindex mcmodel=small
+Generate code for the small code model.  The program and its statically defined
+symbols must be within 4GB of each other.  Pointers are 64 bits.  Programs can
+be statically or dynamically linked.  This is the default code model.
+
+@item -mcmodel=large
+@opindex mcmodel=large
+Generate code for the large code model.  This makes no assumptions about
+addresses and sizes of sections.  Pointers are 64 bits.  Programs can be
+statically linked only.
+
+@item -mstrict-align
+@opindex mstrict-align
+Do not assume that unaligned memory references will be handled by the system.
+
+@item -momit-leaf-frame-pointer
+@itemx -mno-omit-leaf-frame-pointer
+@opindex momit-leaf-frame-pointer
+@opindex mno-omit-leaf-frame-pointer
+Omit or keep the frame pointer in leaf functions.  The former behaviour is the
+default.
+
+@item -mtls-dialect=desc
+@opindex mtls-dialect=desc
+Use TLS descriptors as the thread-local storage mechanism for dynamic accesses
+of TLS variables.  This is the default.
+
+@item -mtls-dialect=traditional
+@opindex mtls-dialect=traditional
+Use traditional TLS as the thread-local storage mechanism for dynamic accesses
+of TLS variables.
+
+@item -march=@var{name}
+@opindex march
+Specify the name of the target architecture, optionally suffixed by one or
+more feature modifiers.  This option has the form
+@option{-march=@var{arch}@r{@{}+@r{[}no@r{]}@var{feature}@r{@}*}}, where the
+only value for @var{arch} is @samp{armv8-a}.  The possible values for
+@var{feature} are documented in the sub-section below.
+
+Where conflicting feature modifiers are specified, the right-most feature is
+used.
+
+GCC uses this name to determine what kind of instructions it can emit when
+generating assembly code.  This option can be used in conjunction with or
+instead of the @option{-mcpu=} option.
+
+@item -mcpu=@var{name}
+@opindex mcpu
+Specify the name of the target processor, optionally suffixed by one or more
+feature modifiers.  This option has the form
+@option{-mcpu=@var{cpu}@r{@{}+@r{[}no@r{]}@var{feature}@r{@}*}}, where the
+possible values for @var{cpu} are @samp{generic}, @samp{large}.  The
+possible values for @var{feature} are documented in the sub-section
+below.
+
+Where conflicting feature modifiers are specified, the right-most feature is
+used.
+
+GCC uses this name to determine what kind of instructions it can emit when
+generating assembly code.
+
+@item -mtune=@var{name}
+@opindex mtune
+Specify the name of the processor to tune the performance for.  The code will
+be tuned as if the target processor were of the type specified in this option,
+but still using instructions compatible with the target processor specified
+by a @option{-mcpu=} option.  This option cannot be suffixed by feature
+modifiers.
+
+@end table
+
+@subsubsection @option{-march} and @option{-mcpu} feature modifiers
+@cindex @option{-march} feature modifiers
+@cindex @option{-mcpu} feature modifiers
+Feature modifiers used with @option{-march} and @option{-mcpu} can be one
+the following:
+
+@table @samp
+@item crypto
+Enable Crypto extension.  This implies Advanced SIMD is enabled.
+@item fp
+Enable floating-point instructions.
+@item simd
+Enable Advanced SIMD instructions.  This implies floating-point instructions
+are enabled.  This is the default for all current possible values for options
+@option{-march} and @option{-mcpu=}.
+@end table
+
+@node Adapteva Epiphany Options
+@subsection Adapteva Epiphany Options
+
+These @samp{-m} options are defined for Adapteva Epiphany:
+
+@table @gcctabopt
+@item -mhalf-reg-file
+@opindex mhalf-reg-file
+Don't allocate any register in the range @code{r32}@dots{}@code{r63}.
+That allows code to run on hardware variants that lack these registers.
+
+@item -mprefer-short-insn-regs
+@opindex mprefer-short-insn-regs
+Preferrentially allocate registers that allow short instruction generation.
+This can result in increased instruction count, so this may either reduce or
+increase overall code size.
+
+@item -mbranch-cost=@var{num}
+@opindex mbranch-cost
+Set the cost of branches to roughly @var{num} ``simple'' instructions.
+This cost is only a heuristic and is not guaranteed to produce
+consistent results across releases.
+
+@item -mcmove
+@opindex mcmove
+Enable the generation of conditional moves.
+
+@item -mnops=@var{num}
+@opindex mnops
+Emit @var{num} NOPs before every other generated instruction.
+
+@item -mno-soft-cmpsf
+@opindex mno-soft-cmpsf
+For single-precision floating-point comparisons, emit an @code{fsub} instruction
+and test the flags.  This is faster than a software comparison, but can
+get incorrect results in the presence of NaNs, or when two different small
+numbers are compared such that their difference is calculated as zero.
+The default is @option{-msoft-cmpsf}, which uses slower, but IEEE-compliant,
+software comparisons.
+
+@item -mstack-offset=@var{num}
+@opindex mstack-offset
+Set the offset between the top of the stack and the stack pointer.
+E.g., a value of 8 means that the eight bytes in the range @code{sp+0@dots{}sp+7}
+can be used by leaf functions without stack allocation.
+Values other than @samp{8} or @samp{16} are untested and unlikely to work.
+Note also that this option changes the ABI; compiling a program with a
+different stack offset than the libraries have been compiled with
+generally does not work.
+This option can be useful if you want to evaluate if a different stack
+offset would give you better code, but to actually use a different stack
+offset to build working programs, it is recommended to configure the
+toolchain with the appropriate @option{--with-stack-offset=@var{num}} option.
+
+@item -mno-round-nearest
+@opindex mno-round-nearest
+Make the scheduler assume that the rounding mode has been set to
+truncating.  The default is @option{-mround-nearest}.
+
+@item -mlong-calls
+@opindex mlong-calls
+If not otherwise specified by an attribute, assume all calls might be beyond
+the offset range of the @code{b} / @code{bl} instructions, and therefore load the
+function address into a register before performing a (otherwise direct) call.
+This is the default.
+
+@item -mshort-calls
+@opindex short-calls
+If not otherwise specified by an attribute, assume all direct calls are
+in the range of the @code{b} / @code{bl} instructions, so use these instructions
+for direct calls.  The default is @option{-mlong-calls}.
+
+@item -msmall16
+@opindex msmall16
+Assume addresses can be loaded as 16-bit unsigned values.  This does not
+apply to function addresses for which @option{-mlong-calls} semantics
+are in effect.
+
+@item -mfp-mode=@var{mode}
+@opindex mfp-mode
+Set the prevailing mode of the floating-point unit.
+This determines the floating-point mode that is provided and expected
+at function call and return time.  Making this mode match the mode you
+predominantly need at function start can make your programs smaller and
+faster by avoiding unnecessary mode switches.
+
+@var{mode} can be set to one the following values:
+
+@table @samp
+@item caller
+Any mode at function entry is valid, and retained or restored when
+the function returns, and when it calls other functions.
+This mode is useful for compiling libraries or other compilation units
+you might want to incorporate into different programs with different
+prevailing FPU modes, and the convenience of being able to use a single
+object file outweighs the size and speed overhead for any extra
+mode switching that might be needed, compared with what would be needed
+with a more specific choice of prevailing FPU mode.
+
+@item truncate
+This is the mode used for floating-point calculations with
+truncating (i.e.@: round towards zero) rounding mode.  That includes
+conversion from floating point to integer.
+
+@item round-nearest
+This is the mode used for floating-point calculations with
+round-to-nearest-or-even rounding mode.
+
+@item int
+This is the mode used to perform integer calculations in the FPU, e.g.@:
+integer multiply, or integer multiply-and-accumulate.
+@end table
+
+The default is @option{-mfp-mode=caller}
+
+@item -mnosplit-lohi
+@itemx -mno-postinc
+@itemx -mno-postmodify
+@opindex mnosplit-lohi
+@opindex mno-postinc
+@opindex mno-postmodify
+Code generation tweaks that disable, respectively, splitting of 32-bit
+loads, generation of post-increment addresses, and generation of
+post-modify addresses.  The defaults are @option{msplit-lohi},
+@option{-mpost-inc}, and @option{-mpost-modify}.
+
+@item -mnovect-double
+@opindex mno-vect-double
+Change the preferred SIMD mode to SImode.  The default is
+@option{-mvect-double}, which uses DImode as preferred SIMD mode.
+
+@item -max-vect-align=@var{num}
+@opindex max-vect-align
+The maximum alignment for SIMD vector mode types.
+@var{num} may be 4 or 8.  The default is 8.
+Note that this is an ABI change, even though many library function
+interfaces are unaffected if they don't use SIMD vector modes
+in places that affect size and/or alignment of relevant types.
+
+@item -msplit-vecmove-early
+@opindex msplit-vecmove-early
+Split vector moves into single word moves before reload.  In theory this
+can give better register allocation, but so far the reverse seems to be
+generally the case.
+
+@item -m1reg-@var{reg}
+@opindex m1reg-
+Specify a register to hold the constant @minus{}1, which makes loading small negative
+constants and certain bitmasks faster.
+Allowable values for @var{reg} are @samp{r43} and @samp{r63},
+which specify use of that register as a fixed register,
+and @samp{none}, which means that no register is used for this
+purpose.  The default is @option{-m1reg-none}.
+
+@end table
+
+@node ARM Options
+@subsection ARM Options
+@cindex ARM options
+
+These @samp{-m} options are defined for Advanced RISC Machines (ARM)
+architectures:
+
+@table @gcctabopt
+@item -mabi=@var{name}
+@opindex mabi
+Generate code for the specified ABI@.  Permissible values are: @samp{apcs-gnu},
+@samp{atpcs}, @samp{aapcs}, @samp{aapcs-linux} and @samp{iwmmxt}.
+
+@item -mapcs-frame
+@opindex mapcs-frame
+Generate a stack frame that is compliant with the ARM Procedure Call
+Standard for all functions, even if this is not strictly necessary for
+correct execution of the code.  Specifying @option{-fomit-frame-pointer}
+with this option causes the stack frames not to be generated for
+leaf functions.  The default is @option{-mno-apcs-frame}.
+
+@item -mapcs
+@opindex mapcs
+This is a synonym for @option{-mapcs-frame}.
+
+@ignore
+@c not currently implemented
+@item -mapcs-stack-check
+@opindex mapcs-stack-check
+Generate code to check the amount of stack space available upon entry to
+every function (that actually uses some stack space).  If there is
+insufficient space available then either the function
+@samp{__rt_stkovf_split_small} or @samp{__rt_stkovf_split_big} is
+called, depending upon the amount of stack space required.  The runtime
+system is required to provide these functions.  The default is
+@option{-mno-apcs-stack-check}, since this produces smaller code.
+
+@c not currently implemented
+@item -mapcs-float
+@opindex mapcs-float
+Pass floating-point arguments using the floating-point registers.  This is
+one of the variants of the APCS@.  This option is recommended if the
+target hardware has a floating-point unit or if a lot of floating-point
+arithmetic is going to be performed by the code.  The default is
+@option{-mno-apcs-float}, since the size of integer-only code is 
+slightly increased if @option{-mapcs-float} is used.
+
+@c not currently implemented
+@item -mapcs-reentrant
+@opindex mapcs-reentrant
+Generate reentrant, position-independent code.  The default is
+@option{-mno-apcs-reentrant}.
+@end ignore
+
+@item -mthumb-interwork
+@opindex mthumb-interwork
+Generate code that supports calling between the ARM and Thumb
+instruction sets.  Without this option, on pre-v5 architectures, the
+two instruction sets cannot be reliably used inside one program.  The
+default is @option{-mno-thumb-interwork}, since slightly larger code
+is generated when @option{-mthumb-interwork} is specified.  In AAPCS
+configurations this option is meaningless.
+
+@item -mno-sched-prolog
+@opindex mno-sched-prolog
+Prevent the reordering of instructions in the function prologue, or the
+merging of those instruction with the instructions in the function's
+body.  This means that all functions start with a recognizable set
+of instructions (or in fact one of a choice from a small set of
+different function prologues), and this information can be used to
+locate the start of functions inside an executable piece of code.  The
+default is @option{-msched-prolog}.
+
+@item -mfloat-abi=@var{name}
+@opindex mfloat-abi
+Specifies which floating-point ABI to use.  Permissible values
+are: @samp{soft}, @samp{softfp} and @samp{hard}.
+
+Specifying @samp{soft} causes GCC to generate output containing
+library calls for floating-point operations.
+@samp{softfp} allows the generation of code using hardware floating-point
+instructions, but still uses the soft-float calling conventions.
+@samp{hard} allows generation of floating-point instructions
+and uses FPU-specific calling conventions.
+
+The default depends on the specific target configuration.  Note that
+the hard-float and soft-float ABIs are not link-compatible; you must
+compile your entire program with the same ABI, and link with a
+compatible set of libraries.
+
+@item -mlittle-endian
+@opindex mlittle-endian
+Generate code for a processor running in little-endian mode.  This is
+the default for all standard configurations.
+
+@item -mbig-endian
+@opindex mbig-endian
+Generate code for a processor running in big-endian mode; the default is
+to compile code for a little-endian processor.
+
+@item -mwords-little-endian
+@opindex mwords-little-endian
+This option only applies when generating code for big-endian processors.
+Generate code for a little-endian word order but a big-endian byte
+order.  That is, a byte order of the form @samp{32107654}.  Note: this
+option should only be used if you require compatibility with code for
+big-endian ARM processors generated by versions of the compiler prior to
+2.8.  This option is now deprecated.
+
+@item -march=@var{name}
+@opindex march
+This specifies the name of the target ARM architecture.  GCC uses this
+name to determine what kind of instructions it can emit when generating
+assembly code.  This option can be used in conjunction with or instead
+of the @option{-mcpu=} option.  Permissible names are: @samp{armv2},
+@samp{armv2a}, @samp{armv3}, @samp{armv3m}, @samp{armv4}, @samp{armv4t},
+@samp{armv5}, @samp{armv5t}, @samp{armv5e}, @samp{armv5te},
+@samp{armv6}, @samp{armv6j},
+@samp{armv6t2}, @samp{armv6z}, @samp{armv6zk}, @samp{armv6-m},
+@samp{armv7}, @samp{armv7-a}, @samp{armv7-r}, @samp{armv7-m}, @samp{armv7e-m}
+@samp{armv8-a},
+@samp{iwmmxt}, @samp{iwmmxt2}, @samp{ep9312}.
+
+@option{-march=native} causes the compiler to auto-detect the architecture
+of the build computer.  At present, this feature is only supported on
+Linux, and not all architectures are recognized.  If the auto-detect is
+unsuccessful the option has no effect.
+
+@item -mtune=@var{name}
+@opindex mtune
+This option specifies the name of the target ARM processor for
+which GCC should tune the performance of the code.
+For some ARM implementations better performance can be obtained by using
+this option.
+Permissible names are: @samp{arm2}, @samp{arm250},
+@samp{arm3}, @samp{arm6}, @samp{arm60}, @samp{arm600}, @samp{arm610},
+@samp{arm620}, @samp{arm7}, @samp{arm7m}, @samp{arm7d}, @samp{arm7dm},
+@samp{arm7di}, @samp{arm7dmi}, @samp{arm70}, @samp{arm700},
+@samp{arm700i}, @samp{arm710}, @samp{arm710c}, @samp{arm7100},
+@samp{arm720},
+@samp{arm7500}, @samp{arm7500fe}, @samp{arm7tdmi}, @samp{arm7tdmi-s},
+@samp{arm710t}, @samp{arm720t}, @samp{arm740t},
+@samp{strongarm}, @samp{strongarm110}, @samp{strongarm1100},
+@samp{strongarm1110},
+@samp{arm8}, @samp{arm810}, @samp{arm9}, @samp{arm9e}, @samp{arm920},
+@samp{arm920t}, @samp{arm922t}, @samp{arm946e-s}, @samp{arm966e-s},
+@samp{arm968e-s}, @samp{arm926ej-s}, @samp{arm940t}, @samp{arm9tdmi},
+@samp{arm10tdmi}, @samp{arm1020t}, @samp{arm1026ej-s},
+@samp{arm10e}, @samp{arm1020e}, @samp{arm1022e},
+@samp{arm1136j-s}, @samp{arm1136jf-s}, @samp{mpcore}, @samp{mpcorenovfp},
+@samp{arm1156t2-s}, @samp{arm1156t2f-s}, @samp{arm1176jz-s}, @samp{arm1176jzf-s},
+@samp{cortex-a5}, @samp{cortex-a7}, @samp{cortex-a8}, @samp{cortex-a9}, 
+@samp{cortex-a15}, @samp{cortex-r4}, @samp{cortex-r4f}, @samp{cortex-r5},
+@samp{cortex-m4}, @samp{cortex-m3},
+@samp{cortex-m1},
+@samp{cortex-m0},
+@samp{cortex-m0plus},
+@samp{marvell-pj4},
+@samp{xscale}, @samp{iwmmxt}, @samp{iwmmxt2}, @samp{ep9312},
+@samp{fa526}, @samp{fa626},
+@samp{fa606te}, @samp{fa626te}, @samp{fmp626}, @samp{fa726te}.
+
+@option{-mtune=generic-@var{arch}} specifies that GCC should tune the
+performance for a blend of processors within architecture @var{arch}.
+The aim is to generate code that run well on the current most popular
+processors, balancing between optimizations that benefit some CPUs in the
+range, and avoiding performance pitfalls of other CPUs.  The effects of
+this option may change in future GCC versions as CPU models come and go.
+
+@option{-mtune=native} causes the compiler to auto-detect the CPU
+of the build computer.  At present, this feature is only supported on
+Linux, and not all architectures are recognized.  If the auto-detect is
+unsuccessful the option has no effect.
+
+@item -mcpu=@var{name}
+@opindex mcpu
+This specifies the name of the target ARM processor.  GCC uses this name
+to derive the name of the target ARM architecture (as if specified
+by @option{-march}) and the ARM processor type for which to tune for
+performance (as if specified by @option{-mtune}).  Where this option
+is used in conjunction with @option{-march} or @option{-mtune},
+those options take precedence over the appropriate part of this option.
+
+Permissible names for this option are the same as those for
+@option{-mtune}.
+
+@option{-mcpu=generic-@var{arch}} is also permissible, and is
+equivalent to @option{-march=@var{arch} -mtune=generic-@var{arch}}.
+See @option{-mtune} for more information.
+
+@option{-mcpu=native} causes the compiler to auto-detect the CPU
+of the build computer.  At present, this feature is only supported on
+Linux, and not all architectures are recognized.  If the auto-detect is
+unsuccessful the option has no effect.
+
+@item -mfpu=@var{name}
+@opindex mfpu
+This specifies what floating-point hardware (or hardware emulation) is
+available on the target.  Permissible names are: @samp{vfp}, @samp{vfpv3},
+@samp{vfpv3-fp16}, @samp{vfpv3-d16}, @samp{vfpv3-d16-fp16}, @samp{vfpv3xd},
+@samp{vfpv3xd-fp16}, @samp{neon}, @samp{neon-fp16}, @samp{vfpv4},
+@samp{vfpv4-d16}, @samp{fpv4-sp-d16}, @samp{neon-vfpv4},
+@samp{fp-armv8}, @samp{neon-fp-armv8}, and @samp{crypto-neon-fp-armv8}.
+
+If @option{-msoft-float} is specified this specifies the format of
+floating-point values.
+
+If the selected floating-point hardware includes the NEON extension
+(e.g. @option{-mfpu}=@samp{neon}), note that floating-point
+operations are not generated by GCC's auto-vectorization pass unless
+@option{-funsafe-math-optimizations} is also specified.  This is
+because NEON hardware does not fully implement the IEEE 754 standard for
+floating-point arithmetic (in particular denormal values are treated as
+zero), so the use of NEON instructions may lead to a loss of precision.
+
+@item -mfp16-format=@var{name}
+@opindex mfp16-format
+Specify the format of the @code{__fp16} half-precision floating-point type.
+Permissible names are @samp{none}, @samp{ieee}, and @samp{alternative};
+the default is @samp{none}, in which case the @code{__fp16} type is not
+defined.  @xref{Half-Precision}, for more information.
+
+@item -mstructure-size-boundary=@var{n}
+@opindex mstructure-size-boundary
+The sizes of all structures and unions are rounded up to a multiple
+of the number of bits set by this option.  Permissible values are 8, 32
+and 64.  The default value varies for different toolchains.  For the COFF
+targeted toolchain the default value is 8.  A value of 64 is only allowed
+if the underlying ABI supports it.
+
+Specifying a larger number can produce faster, more efficient code, but
+can also increase the size of the program.  Different values are potentially
+incompatible.  Code compiled with one value cannot necessarily expect to
+work with code or libraries compiled with another value, if they exchange
+information using structures or unions.
+
+@item -mabort-on-noreturn
+@opindex mabort-on-noreturn
+Generate a call to the function @code{abort} at the end of a
+@code{noreturn} function.  It is executed if the function tries to
+return.
+
+@item -mlong-calls
+@itemx -mno-long-calls
+@opindex mlong-calls
+@opindex mno-long-calls
+Tells the compiler to perform function calls by first loading the
+address of the function into a register and then performing a subroutine
+call on this register.  This switch is needed if the target function
+lies outside of the 64-megabyte addressing range of the offset-based
+version of subroutine call instruction.
+
+Even if this switch is enabled, not all function calls are turned
+into long calls.  The heuristic is that static functions, functions
+that have the @samp{short-call} attribute, functions that are inside
+the scope of a @samp{#pragma no_long_calls} directive, and functions whose
+definitions have already been compiled within the current compilation
+unit are not turned into long calls.  The exceptions to this rule are
+that weak function definitions, functions with the @samp{long-call}
+attribute or the @samp{section} attribute, and functions that are within
+the scope of a @samp{#pragma long_calls} directive are always
+turned into long calls.
+
+This feature is not enabled by default.  Specifying
+@option{-mno-long-calls} restores the default behavior, as does
+placing the function calls within the scope of a @samp{#pragma
+long_calls_off} directive.  Note these switches have no effect on how
+the compiler generates code to handle function calls via function
+pointers.
+
+@item -msingle-pic-base
+@opindex msingle-pic-base
+Treat the register used for PIC addressing as read-only, rather than
+loading it in the prologue for each function.  The runtime system is
+responsible for initializing this register with an appropriate value
+before execution begins.
+
+@item -mpic-register=@var{reg}
+@opindex mpic-register
+Specify the register to be used for PIC addressing.
+For standard PIC base case, the default will be any suitable register
+determined by compiler.  For single PIC base case, the default is
+@samp{R9} if target is EABI based or stack-checking is enabled,
+otherwise the default is @samp{R10}.
+
+@item -mpoke-function-name
+@opindex mpoke-function-name
+Write the name of each function into the text section, directly
+preceding the function prologue.  The generated code is similar to this:
+
+@smallexample
+     t0
+         .ascii "arm_poke_function_name", 0
+         .align
+     t1
+         .word 0xff000000 + (t1 - t0)
+     arm_poke_function_name
+         mov     ip, sp
+         stmfd   sp!, @{fp, ip, lr, pc@}
+         sub     fp, ip, #4
+@end smallexample
+
+When performing a stack backtrace, code can inspect the value of
+@code{pc} stored at @code{fp + 0}.  If the trace function then looks at
+location @code{pc - 12} and the top 8 bits are set, then we know that
+there is a function name embedded immediately preceding this location
+and has length @code{((pc[-3]) & 0xff000000)}.
+
+@item -mthumb
+@itemx -marm
+@opindex marm
+@opindex mthumb
+
+Select between generating code that executes in ARM and Thumb
+states.  The default for most configurations is to generate code
+that executes in ARM state, but the default can be changed by
+configuring GCC with the @option{--with-mode=}@var{state}
+configure option.
+
+@item -mtpcs-frame
+@opindex mtpcs-frame
+Generate a stack frame that is compliant with the Thumb Procedure Call
+Standard for all non-leaf functions.  (A leaf function is one that does
+not call any other functions.)  The default is @option{-mno-tpcs-frame}.
+
+@item -mtpcs-leaf-frame
+@opindex mtpcs-leaf-frame
+Generate a stack frame that is compliant with the Thumb Procedure Call
+Standard for all leaf functions.  (A leaf function is one that does
+not call any other functions.)  The default is @option{-mno-apcs-leaf-frame}.
+
+@item -mcallee-super-interworking
+@opindex mcallee-super-interworking
+Gives all externally visible functions in the file being compiled an ARM
+instruction set header which switches to Thumb mode before executing the
+rest of the function.  This allows these functions to be called from
+non-interworking code.  This option is not valid in AAPCS configurations
+because interworking is enabled by default.
+
+@item -mcaller-super-interworking
+@opindex mcaller-super-interworking
+Allows calls via function pointers (including virtual functions) to
+execute correctly regardless of whether the target code has been
+compiled for interworking or not.  There is a small overhead in the cost
+of executing a function pointer if this option is enabled.  This option
+is not valid in AAPCS configurations because interworking is enabled
+by default.
+
+@item -mtp=@var{name}
+@opindex mtp
+Specify the access model for the thread local storage pointer.  The valid
+models are @option{soft}, which generates calls to @code{__aeabi_read_tp},
+@option{cp15}, which fetches the thread pointer from @code{cp15} directly
+(supported in the arm6k architecture), and @option{auto}, which uses the
+best available method for the selected processor.  The default setting is
+@option{auto}.
+
+@item -mtls-dialect=@var{dialect}
+@opindex mtls-dialect
+Specify the dialect to use for accessing thread local storage.  Two
+@var{dialect}s are supported---@samp{gnu} and @samp{gnu2}.  The
+@samp{gnu} dialect selects the original GNU scheme for supporting
+local and global dynamic TLS models.  The @samp{gnu2} dialect
+selects the GNU descriptor scheme, which provides better performance
+for shared libraries.  The GNU descriptor scheme is compatible with
+the original scheme, but does require new assembler, linker and
+library support.  Initial and local exec TLS models are unaffected by
+this option and always use the original scheme.
+
+@item -mword-relocations
+@opindex mword-relocations
+Only generate absolute relocations on word-sized values (i.e. R_ARM_ABS32).
+This is enabled by default on targets (uClinux, SymbianOS) where the runtime
+loader imposes this restriction, and when @option{-fpic} or @option{-fPIC}
+is specified.
+
+@item -mfix-cortex-m3-ldrd
+@opindex mfix-cortex-m3-ldrd
+Some Cortex-M3 cores can cause data corruption when @code{ldrd} instructions
+with overlapping destination and base registers are used.  This option avoids
+generating these instructions.  This option is enabled by default when
+@option{-mcpu=cortex-m3} is specified.
+
+@item -munaligned-access
+@itemx -mno-unaligned-access
+@opindex munaligned-access
+@opindex mno-unaligned-access
+Enables (or disables) reading and writing of 16- and 32- bit values
+from addresses that are not 16- or 32- bit aligned.  By default
+unaligned access is disabled for all pre-ARMv6 and all ARMv6-M
+architectures, and enabled for all other architectures.  If unaligned
+access is not enabled then words in packed data structures will be
+accessed a byte at a time.
+
+The ARM attribute @code{Tag_CPU_unaligned_access} will be set in the
+generated object file to either true or false, depending upon the
+setting of this option.  If unaligned access is enabled then the
+preprocessor symbol @code{__ARM_FEATURE_UNALIGNED} will also be
+defined.
+
+@end table
+
+@node AVR Options
+@subsection AVR Options
+@cindex AVR Options
+
+These options are defined for AVR implementations:
+
+@table @gcctabopt
+@item -mmcu=@var{mcu}
+@opindex mmcu
+Specify Atmel AVR instruction set architectures (ISA) or MCU type.
+
+The default for this option is@tie{}@code{avr2}.
+
+GCC supports the following AVR devices and ISAs:
+
+@include avr-mmcu.texi
+
+@item -maccumulate-args
+@opindex maccumulate-args
+Accumulate outgoing function arguments and acquire/release the needed
+stack space for outgoing function arguments once in function
+prologue/epilogue.  Without this option, outgoing arguments are pushed
+before calling a function and popped afterwards.
+
+Popping the arguments after the function call can be expensive on
+AVR so that accumulating the stack space might lead to smaller
+executables because arguments need not to be removed from the
+stack after such a function call.
+
+This option can lead to reduced code size for functions that perform
+several calls to functions that get their arguments on the stack like
+calls to printf-like functions.
+
+@item -mbranch-cost=@var{cost}
+@opindex mbranch-cost
+Set the branch costs for conditional branch instructions to
+@var{cost}.  Reasonable values for @var{cost} are small, non-negative
+integers. The default branch cost is 0.
+
+@item -mcall-prologues
+@opindex mcall-prologues
+Functions prologues/epilogues are expanded as calls to appropriate
+subroutines.  Code size is smaller.
+
+@item -mint8
+@opindex mint8
+Assume @code{int} to be 8-bit integer.  This affects the sizes of all types: a
+@code{char} is 1 byte, an @code{int} is 1 byte, a @code{long} is 2 bytes,
+and @code{long long} is 4 bytes.  Please note that this option does not
+conform to the C standards, but it results in smaller code
+size.
+
+@item -mno-interrupts
+@opindex mno-interrupts
+Generated code is not compatible with hardware interrupts.
+Code size is smaller.
+
+@item -mrelax
+@opindex mrelax
+Try to replace @code{CALL} resp.@: @code{JMP} instruction by the shorter
+@code{RCALL} resp.@: @code{RJMP} instruction if applicable.
+Setting @code{-mrelax} just adds the @code{--relax} option to the
+linker command line when the linker is called.
+
+Jump relaxing is performed by the linker because jump offsets are not
+known before code is located. Therefore, the assembler code generated by the
+compiler is the same, but the instructions in the executable may
+differ from instructions in the assembler code.
+
+Relaxing must be turned on if linker stubs are needed, see the
+section on @code{EIND} and linker stubs below.
+
+@item -msp8
+@opindex msp8
+Treat the stack pointer register as an 8-bit register,
+i.e.@: assume the high byte of the stack pointer is zero.
+In general, you don't need to set this option by hand.
+
+This option is used internally by the compiler to select and
+build multilibs for architectures @code{avr2} and @code{avr25}.
+These architectures mix devices with and without @code{SPH}.
+For any setting other than @code{-mmcu=avr2} or @code{-mmcu=avr25}
+the compiler driver will add or remove this option from the compiler
+proper's command line, because the compiler then knows if the device
+or architecture has an 8-bit stack pointer and thus no @code{SPH}
+register or not.
+
+@item -mstrict-X
+@opindex mstrict-X
+Use address register @code{X} in a way proposed by the hardware.  This means
+that @code{X} is only used in indirect, post-increment or
+pre-decrement addressing.
+
+Without this option, the @code{X} register may be used in the same way
+as @code{Y} or @code{Z} which then is emulated by additional
+instructions.  
+For example, loading a value with @code{X+const} addressing with a
+small non-negative @code{const < 64} to a register @var{Rn} is
+performed as
+
+@example
+adiw r26, const   ; X += const
+ld   @var{Rn}, X        ; @var{Rn} = *X
+sbiw r26, const   ; X -= const
+@end example
+
+@item -mtiny-stack
+@opindex mtiny-stack
+Only change the lower 8@tie{}bits of the stack pointer.
+
+@item -Waddr-space-convert
+@opindex Waddr-space-convert
+Warn about conversions between address spaces in the case where the
+resulting address space is not contained in the incoming address space.
+@end table
+
+@subsubsection @code{EIND} and Devices with more than 128 Ki Bytes of Flash
+@cindex @code{EIND}
+Pointers in the implementation are 16@tie{}bits wide.
+The address of a function or label is represented as word address so
+that indirect jumps and calls can target any code address in the
+range of 64@tie{}Ki words.
+
+In order to facilitate indirect jump on devices with more than 128@tie{}Ki
+bytes of program memory space, there is a special function register called
+@code{EIND} that serves as most significant part of the target address
+when @code{EICALL} or @code{EIJMP} instructions are used.
+
+Indirect jumps and calls on these devices are handled as follows by
+the compiler and are subject to some limitations:
+
+@itemize @bullet
+
+@item
+The compiler never sets @code{EIND}.
+
+@item
+The compiler uses @code{EIND} implicitely in @code{EICALL}/@code{EIJMP}
+instructions or might read @code{EIND} directly in order to emulate an
+indirect call/jump by means of a @code{RET} instruction.
+
+@item
+The compiler assumes that @code{EIND} never changes during the startup
+code or during the application. In particular, @code{EIND} is not
+saved/restored in function or interrupt service routine
+prologue/epilogue.
+
+@item
+For indirect calls to functions and computed goto, the linker
+generates @emph{stubs}. Stubs are jump pads sometimes also called
+@emph{trampolines}. Thus, the indirect call/jump jumps to such a stub.
+The stub contains a direct jump to the desired address.
+
+@item
+Linker relaxation must be turned on so that the linker will generate
+the stubs correctly an all situaltion. See the compiler option
+@code{-mrelax} and the linler option @code{--relax}.
+There are corner cases where the linker is supposed to generate stubs
+but aborts without relaxation and without a helpful error message.
+
+@item
+The default linker script is arranged for code with @code{EIND = 0}.
+If code is supposed to work for a setup with @code{EIND != 0}, a custom
+linker script has to be used in order to place the sections whose
+name start with @code{.trampolines} into the segment where @code{EIND}
+points to.
+
+@item
+The startup code from libgcc never sets @code{EIND}.
+Notice that startup code is a blend of code from libgcc and AVR-LibC.
+For the impact of AVR-LibC on @code{EIND}, see the
+@w{@uref{http://nongnu.org/avr-libc/user-manual/,AVR-LibC user manual}}.
+
+@item
+It is legitimate for user-specific startup code to set up @code{EIND}
+early, for example by means of initialization code located in
+section @code{.init3}. Such code runs prior to general startup code
+that initializes RAM and calls constructors, but after the bit
+of startup code from AVR-LibC that sets @code{EIND} to the segment
+where the vector table is located.
+@example
+#include <avr/io.h>
+
+static void
+__attribute__((section(".init3"),naked,used,no_instrument_function))
+init3_set_eind (void)
+@{
+  __asm volatile ("ldi r24,pm_hh8(__trampolines_start)\n\t"
+                  "out %i0,r24" :: "n" (&EIND) : "r24","memory");
+@}
+@end example
+
+@noindent
+The @code{__trampolines_start} symbol is defined in the linker script.
+
+@item
+Stubs are generated automatically by the linker if
+the following two conditions are met:
+@itemize @minus
+
+@item The address of a label is taken by means of the @code{gs} modifier
+(short for @emph{generate stubs}) like so:
+@example
+LDI r24, lo8(gs(@var{func}))
+LDI r25, hi8(gs(@var{func}))
+@end example
+@item The final location of that label is in a code segment
+@emph{outside} the segment where the stubs are located.
+@end itemize
+
+@item
+The compiler emits such @code{gs} modifiers for code labels in the
+following situations:
+@itemize @minus
+@item Taking address of a function or code label.
+@item Computed goto.
+@item If prologue-save function is used, see @option{-mcall-prologues}
+command-line option.
+@item Switch/case dispatch tables. If you do not want such dispatch
+tables you can specify the @option{-fno-jump-tables} command-line option.
+@item C and C++ constructors/destructors called during startup/shutdown.
+@item If the tools hit a @code{gs()} modifier explained above.
+@end itemize
+
+@item
+Jumping to non-symbolic addresses like so is @emph{not} supported:
+
+@example
+int main (void)
+@{
+    /* Call function at word address 0x2 */
+    return ((int(*)(void)) 0x2)();
+@}
+@end example
+
+Instead, a stub has to be set up, i.e.@: the function has to be called
+through a symbol (@code{func_4} in the example):
+
+@example
+int main (void)
+@{
+    extern int func_4 (void);
+
+    /* Call function at byte address 0x4 */
+    return func_4();
+@}
+@end example
+
+and the application be linked with @code{-Wl,--defsym,func_4=0x4}.
+Alternatively, @code{func_4} can be defined in the linker script.
+@end itemize
+
+@subsubsection Handling of the @code{RAMPD}, @code{RAMPX}, @code{RAMPY} and @code{RAMPZ} Special Function Registers
+@cindex @code{RAMPD}
+@cindex @code{RAMPX}
+@cindex @code{RAMPY}
+@cindex @code{RAMPZ}
+Some AVR devices support memories larger than the 64@tie{}KiB range
+that can be accessed with 16-bit pointers.  To access memory locations
+outside this 64@tie{}KiB range, the contentent of a @code{RAMP}
+register is used as high part of the address:
+The @code{X}, @code{Y}, @code{Z} address register is concatenated
+with the @code{RAMPX}, @code{RAMPY}, @code{RAMPZ} special function
+register, respectively, to get a wide address. Similarly,
+@code{RAMPD} is used together with direct addressing.
+
+@itemize
+@item
+The startup code initializes the @code{RAMP} special function
+registers with zero.
+
+@item
+If a @ref{AVR Named Address Spaces,named address space} other than
+generic or @code{__flash} is used, then @code{RAMPZ} is set
+as needed before the operation.
+
+@item
+If the device supports RAM larger than 64@tie{KiB} and the compiler
+needs to change @code{RAMPZ} to accomplish an operation, @code{RAMPZ}
+is reset to zero after the operation.
+
+@item
+If the device comes with a specific @code{RAMP} register, the ISR
+prologue/epilogue saves/restores that SFR and initializes it with
+zero in case the ISR code might (implicitly) use it.
+
+@item
+RAM larger than 64@tie{KiB} is not supported by GCC for AVR targets.
+If you use inline assembler to read from locations outside the
+16-bit address range and change one of the @code{RAMP} registers,
+you must reset it to zero after the access.
+
+@end itemize
+
+@subsubsection AVR Built-in Macros
+
+GCC defines several built-in macros so that the user code can test
+for the presence or absence of features.  Almost any of the following
+built-in macros are deduced from device capabilities and thus
+triggered by the @code{-mmcu=} command-line option.
+
+For even more AVR-specific built-in macros see
+@ref{AVR Named Address Spaces} and @ref{AVR Built-in Functions}.
+
+@table @code
+
+@item __AVR_ARCH__
+Build-in macro that resolves to a decimal number that identifies the
+architecture and depends on the @code{-mmcu=@var{mcu}} option.
+Possible values are:
+
+@code{2}, @code{25}, @code{3}, @code{31}, @code{35},
+@code{4}, @code{5}, @code{51}, @code{6}, @code{102}, @code{104},
+@code{105}, @code{106}, @code{107}
+
+for @var{mcu}=@code{avr2}, @code{avr25}, @code{avr3},
+@code{avr31}, @code{avr35}, @code{avr4}, @code{avr5}, @code{avr51},
+@code{avr6}, @code{avrxmega2}, @code{avrxmega4}, @code{avrxmega5},
+@code{avrxmega6}, @code{avrxmega7}, respectively.
+If @var{mcu} specifies a device, this built-in macro is set
+accordingly. For example, with @code{-mmcu=atmega8} the macro will be
+defined to @code{4}.
+
+@item __AVR_@var{Device}__
+Setting @code{-mmcu=@var{device}} defines this built-in macro which reflects
+the device's name. For example, @code{-mmcu=atmega8} defines the
+built-in macro @code{__AVR_ATmega8__}, @code{-mmcu=attiny261a} defines
+@code{__AVR_ATtiny261A__}, etc.
+
+The built-in macros' names follow
+the scheme @code{__AVR_@var{Device}__} where @var{Device} is
+the device name as from the AVR user manual. The difference between
+@var{Device} in the built-in macro and @var{device} in
+@code{-mmcu=@var{device}} is that the latter is always lowercase.
+
+If @var{device} is not a device but only a core architecture like
+@code{avr51}, this macro will not be defined.
+
+@item __AVR_XMEGA__
+The device / architecture belongs to the XMEGA family of devices.
+
+@item __AVR_HAVE_ELPM__
+The device has the the @code{ELPM} instruction.
+
+@item __AVR_HAVE_ELPMX__
+The device has the @code{ELPM R@var{n},Z} and @code{ELPM
+R@var{n},Z+} instructions.
+
+@item __AVR_HAVE_MOVW__
+The device has the @code{MOVW} instruction to perform 16-bit
+register-register moves.
+
+@item __AVR_HAVE_LPMX__
+The device has the @code{LPM R@var{n},Z} and
+@code{LPM R@var{n},Z+} instructions.
+
+@item __AVR_HAVE_MUL__
+The device has a hardware multiplier. 
+
+@item __AVR_HAVE_JMP_CALL__
+The device has the @code{JMP} and @code{CALL} instructions.
+This is the case for devices with at least 16@tie{}KiB of program
+memory.
+
+@item __AVR_HAVE_EIJMP_EICALL__
+@itemx __AVR_3_BYTE_PC__
+The device has the @code{EIJMP} and @code{EICALL} instructions.
+This is the case for devices with more than 128@tie{}KiB of program memory.
+This also means that the program counter
+(PC) is 3@tie{}bytes wide.
+
+@item __AVR_2_BYTE_PC__
+The program counter (PC) is 2@tie{}bytes wide. This is the case for devices
+with up to 128@tie{}KiB of program memory.
+
+@item __AVR_HAVE_8BIT_SP__
+@itemx __AVR_HAVE_16BIT_SP__
+The stack pointer (SP) register is treated as 8-bit respectively
+16-bit register by the compiler.
+The definition of these macros is affected by @code{-mtiny-stack}.
+
+@item __AVR_HAVE_SPH__
+@itemx __AVR_SP8__
+The device has the SPH (high part of stack pointer) special function
+register or has an 8-bit stack pointer, respectively.
+The definition of these macros is affected by @code{-mmcu=} and
+in the cases of @code{-mmcu=avr2} and @code{-mmcu=avr25} also
+by @code{-msp8}.
+
+@item __AVR_HAVE_RAMPD__
+@itemx __AVR_HAVE_RAMPX__
+@itemx __AVR_HAVE_RAMPY__
+@itemx __AVR_HAVE_RAMPZ__
+The device has the @code{RAMPD}, @code{RAMPX}, @code{RAMPY},
+@code{RAMPZ} special function register, respectively.
+
+@item __NO_INTERRUPTS__
+This macro reflects the @code{-mno-interrupts} command line option.
+
+@item __AVR_ERRATA_SKIP__
+@itemx __AVR_ERRATA_SKIP_JMP_CALL__
+Some AVR devices (AT90S8515, ATmega103) must not skip 32-bit
+instructions because of a hardware erratum.  Skip instructions are
+@code{SBRS}, @code{SBRC}, @code{SBIS}, @code{SBIC} and @code{CPSE}.
+The second macro is only defined if @code{__AVR_HAVE_JMP_CALL__} is also
+set.
+
+@item __AVR_SFR_OFFSET__=@var{offset}
+Instructions that can address I/O special function registers directly
+like @code{IN}, @code{OUT}, @code{SBI}, etc.@: may use a different
+address as if addressed by an instruction to access RAM like @code{LD}
+or @code{STS}. This offset depends on the device architecture and has
+to be subtracted from the RAM address in order to get the
+respective I/O@tie{}address.
+
+@item __WITH_AVRLIBC__
+The compiler is configured to be used together with AVR-Libc.
+See the @code{--with-avrlibc} configure option.
+
+@end table
+
+@node Blackfin Options
+@subsection Blackfin Options
+@cindex Blackfin Options
+
+@table @gcctabopt
+@item -mcpu=@var{cpu}@r{[}-@var{sirevision}@r{]}
+@opindex mcpu=
+Specifies the name of the target Blackfin processor.  Currently, @var{cpu}
+can be one of @samp{bf512}, @samp{bf514}, @samp{bf516}, @samp{bf518},
+@samp{bf522}, @samp{bf523}, @samp{bf524}, @samp{bf525}, @samp{bf526},
+@samp{bf527}, @samp{bf531}, @samp{bf532}, @samp{bf533},
+@samp{bf534}, @samp{bf536}, @samp{bf537}, @samp{bf538}, @samp{bf539},
+@samp{bf542}, @samp{bf544}, @samp{bf547}, @samp{bf548}, @samp{bf549},
+@samp{bf542m}, @samp{bf544m}, @samp{bf547m}, @samp{bf548m}, @samp{bf549m},
+@samp{bf561}, @samp{bf592}.
+
+The optional @var{sirevision} specifies the silicon revision of the target
+Blackfin processor.  Any workarounds available for the targeted silicon revision
+are enabled.  If @var{sirevision} is @samp{none}, no workarounds are enabled.
+If @var{sirevision} is @samp{any}, all workarounds for the targeted processor
+are enabled.  The @code{__SILICON_REVISION__} macro is defined to two
+hexadecimal digits representing the major and minor numbers in the silicon
+revision.  If @var{sirevision} is @samp{none}, the @code{__SILICON_REVISION__}
+is not defined.  If @var{sirevision} is @samp{any}, the
+@code{__SILICON_REVISION__} is defined to be @code{0xffff}.
+If this optional @var{sirevision} is not used, GCC assumes the latest known
+silicon revision of the targeted Blackfin processor.
+
+GCC defines a preprocessor macro for the specified @var{cpu}.
+For the @samp{bfin-elf} toolchain, this option causes the hardware BSP
+provided by libgloss to be linked in if @option{-msim} is not given.
+
+Without this option, @samp{bf532} is used as the processor by default.
+
+Note that support for @samp{bf561} is incomplete.  For @samp{bf561},
+only the preprocessor macro is defined.
+
+@item -msim
+@opindex msim
+Specifies that the program will be run on the simulator.  This causes
+the simulator BSP provided by libgloss to be linked in.  This option
+has effect only for @samp{bfin-elf} toolchain.
+Certain other options, such as @option{-mid-shared-library} and
+@option{-mfdpic}, imply @option{-msim}.
+
+@item -momit-leaf-frame-pointer
+@opindex momit-leaf-frame-pointer
+Don't keep the frame pointer in a register for leaf functions.  This
+avoids the instructions to save, set up and restore frame pointers and
+makes an extra register available in leaf functions.  The option
+@option{-fomit-frame-pointer} removes the frame pointer for all functions,
+which might make debugging harder.
+
+@item -mspecld-anomaly
+@opindex mspecld-anomaly
+When enabled, the compiler ensures that the generated code does not
+contain speculative loads after jump instructions. If this option is used,
+@code{__WORKAROUND_SPECULATIVE_LOADS} is defined.
+
+@item -mno-specld-anomaly
+@opindex mno-specld-anomaly
+Don't generate extra code to prevent speculative loads from occurring.
+
+@item -mcsync-anomaly
+@opindex mcsync-anomaly
+When enabled, the compiler ensures that the generated code does not
+contain CSYNC or SSYNC instructions too soon after conditional branches.
+If this option is used, @code{__WORKAROUND_SPECULATIVE_SYNCS} is defined.
+
+@item -mno-csync-anomaly
+@opindex mno-csync-anomaly
+Don't generate extra code to prevent CSYNC or SSYNC instructions from
+occurring too soon after a conditional branch.
+
+@item -mlow-64k
+@opindex mlow-64k
+When enabled, the compiler is free to take advantage of the knowledge that
+the entire program fits into the low 64k of memory.
+
+@item -mno-low-64k
+@opindex mno-low-64k
+Assume that the program is arbitrarily large.  This is the default.
+
+@item -mstack-check-l1
+@opindex mstack-check-l1
+Do stack checking using information placed into L1 scratchpad memory by the
+uClinux kernel.
+
+@item -mid-shared-library
+@opindex mid-shared-library
+Generate code that supports shared libraries via the library ID method.
+This allows for execute in place and shared libraries in an environment
+without virtual memory management.  This option implies @option{-fPIC}.
+With a @samp{bfin-elf} target, this option implies @option{-msim}.
+
+@item -mno-id-shared-library
+@opindex mno-id-shared-library
+Generate code that doesn't assume ID-based shared libraries are being used.
+This is the default.
+
+@item -mleaf-id-shared-library
+@opindex mleaf-id-shared-library
+Generate code that supports shared libraries via the library ID method,
+but assumes that this library or executable won't link against any other
+ID shared libraries.  That allows the compiler to use faster code for jumps
+and calls.
+
+@item -mno-leaf-id-shared-library
+@opindex mno-leaf-id-shared-library
+Do not assume that the code being compiled won't link against any ID shared
+libraries.  Slower code is generated for jump and call insns.
+
+@item -mshared-library-id=n
+@opindex mshared-library-id
+Specifies the identification number of the ID-based shared library being
+compiled.  Specifying a value of 0 generates more compact code; specifying
+other values forces the allocation of that number to the current
+library but is no more space- or time-efficient than omitting this option.
+
+@item -msep-data
+@opindex msep-data
+Generate code that allows the data segment to be located in a different
+area of memory from the text segment.  This allows for execute in place in
+an environment without virtual memory management by eliminating relocations
+against the text section.
+
+@item -mno-sep-data
+@opindex mno-sep-data
+Generate code that assumes that the data segment follows the text segment.
+This is the default.
+
+@item -mlong-calls
+@itemx -mno-long-calls
+@opindex mlong-calls
+@opindex mno-long-calls
+Tells the compiler to perform function calls by first loading the
+address of the function into a register and then performing a subroutine
+call on this register.  This switch is needed if the target function
+lies outside of the 24-bit addressing range of the offset-based
+version of subroutine call instruction.
+
+This feature is not enabled by default.  Specifying
+@option{-mno-long-calls} restores the default behavior.  Note these
+switches have no effect on how the compiler generates code to handle
+function calls via function pointers.
+
+@item -mfast-fp
+@opindex mfast-fp
+Link with the fast floating-point library. This library relaxes some of
+the IEEE floating-point standard's rules for checking inputs against
+Not-a-Number (NAN), in the interest of performance.
+
+@item -minline-plt
+@opindex minline-plt
+Enable inlining of PLT entries in function calls to functions that are
+not known to bind locally.  It has no effect without @option{-mfdpic}.
+
+@item -mmulticore
+@opindex mmulticore
+Build a standalone application for multicore Blackfin processors. 
+This option causes proper start files and link scripts supporting 
+multicore to be used, and defines the macro @code{__BFIN_MULTICORE}. 
+It can only be used with @option{-mcpu=bf561@r{[}-@var{sirevision}@r{]}}. 
+
+This option can be used with @option{-mcorea} or @option{-mcoreb}, which
+selects the one-application-per-core programming model.  Without
+@option{-mcorea} or @option{-mcoreb}, the single-application/dual-core
+programming model is used. In this model, the main function of Core B
+should be named as @code{coreb_main}.
+
+If this option is not used, the single-core application programming
+model is used.
+
+@item -mcorea
+@opindex mcorea
+Build a standalone application for Core A of BF561 when using
+the one-application-per-core programming model. Proper start files
+and link scripts are used to support Core A, and the macro
+@code{__BFIN_COREA} is defined.
+This option can only be used in conjunction with @option{-mmulticore}.
+
+@item -mcoreb
+@opindex mcoreb
+Build a standalone application for Core B of BF561 when using
+the one-application-per-core programming model. Proper start files
+and link scripts are used to support Core B, and the macro
+@code{__BFIN_COREB} is defined. When this option is used, @code{coreb_main}
+should be used instead of @code{main}. 
+This option can only be used in conjunction with @option{-mmulticore}.
+
+@item -msdram
+@opindex msdram
+Build a standalone application for SDRAM. Proper start files and
+link scripts are used to put the application into SDRAM, and the macro
+@code{__BFIN_SDRAM} is defined.
+The loader should initialize SDRAM before loading the application.
+
+@item -micplb
+@opindex micplb
+Assume that ICPLBs are enabled at run time.  This has an effect on certain
+anomaly workarounds.  For Linux targets, the default is to assume ICPLBs
+are enabled; for standalone applications the default is off.
+@end table
+
+@node C6X Options
+@subsection C6X Options
+@cindex C6X Options
+
+@table @gcctabopt
+@item -march=@var{name}
+@opindex march
+This specifies the name of the target architecture.  GCC uses this
+name to determine what kind of instructions it can emit when generating
+assembly code.  Permissible names are: @samp{c62x},
+@samp{c64x}, @samp{c64x+}, @samp{c67x}, @samp{c67x+}, @samp{c674x}.
+
+@item -mbig-endian
+@opindex mbig-endian
+Generate code for a big-endian target.
+
+@item -mlittle-endian
+@opindex mlittle-endian
+Generate code for a little-endian target.  This is the default.
+
+@item -msim
+@opindex msim
+Choose startup files and linker script suitable for the simulator.
+
+@item -msdata=default
+@opindex msdata=default
+Put small global and static data in the @samp{.neardata} section,
+which is pointed to by register @code{B14}.  Put small uninitialized
+global and static data in the @samp{.bss} section, which is adjacent
+to the @samp{.neardata} section.  Put small read-only data into the
+@samp{.rodata} section.  The corresponding sections used for large
+pieces of data are @samp{.fardata}, @samp{.far} and @samp{.const}.
+
+@item -msdata=all
+@opindex msdata=all
+Put all data, not just small objects, into the sections reserved for
+small data, and use addressing relative to the @code{B14} register to
+access them.
+
+@item -msdata=none
+@opindex msdata=none
+Make no use of the sections reserved for small data, and use absolute
+addresses to access all data.  Put all initialized global and static
+data in the @samp{.fardata} section, and all uninitialized data in the
+@samp{.far} section.  Put all constant data into the @samp{.const}
+section.
+@end table
+
+@node CRIS Options
+@subsection CRIS Options
+@cindex CRIS Options
+
+These options are defined specifically for the CRIS ports.
+
+@table @gcctabopt
+@item -march=@var{architecture-type}
+@itemx -mcpu=@var{architecture-type}
+@opindex march
+@opindex mcpu
+Generate code for the specified architecture.  The choices for
+@var{architecture-type} are @samp{v3}, @samp{v8} and @samp{v10} for
+respectively ETRAX@w{ }4, ETRAX@w{ }100, and ETRAX@w{ }100@w{ }LX@.
+Default is @samp{v0} except for cris-axis-linux-gnu, where the default is
+@samp{v10}.
+
+@item -mtune=@var{architecture-type}
+@opindex mtune
+Tune to @var{architecture-type} everything applicable about the generated
+code, except for the ABI and the set of available instructions.  The
+choices for @var{architecture-type} are the same as for
+@option{-march=@var{architecture-type}}.
+
+@item -mmax-stack-frame=@var{n}
+@opindex mmax-stack-frame
+Warn when the stack frame of a function exceeds @var{n} bytes.
+
+@item -metrax4
+@itemx -metrax100
+@opindex metrax4
+@opindex metrax100
+The options @option{-metrax4} and @option{-metrax100} are synonyms for
+@option{-march=v3} and @option{-march=v8} respectively.
+
+@item -mmul-bug-workaround
+@itemx -mno-mul-bug-workaround
+@opindex mmul-bug-workaround
+@opindex mno-mul-bug-workaround
+Work around a bug in the @code{muls} and @code{mulu} instructions for CPU
+models where it applies.  This option is active by default.
+
+@item -mpdebug
+@opindex mpdebug
+Enable CRIS-specific verbose debug-related information in the assembly
+code.  This option also has the effect of turning off the @samp{#NO_APP}
+formatted-code indicator to the assembler at the beginning of the
+assembly file.
+
+@item -mcc-init
+@opindex mcc-init
+Do not use condition-code results from previous instruction; always emit
+compare and test instructions before use of condition codes.
+
+@item -mno-side-effects
+@opindex mno-side-effects
+Do not emit instructions with side effects in addressing modes other than
+post-increment.
+
+@item -mstack-align
+@itemx -mno-stack-align
+@itemx -mdata-align
+@itemx -mno-data-align
+@itemx -mconst-align
+@itemx -mno-const-align
+@opindex mstack-align
+@opindex mno-stack-align
+@opindex mdata-align
+@opindex mno-data-align
+@opindex mconst-align
+@opindex mno-const-align
+These options (@samp{no-} options) arrange (eliminate arrangements) for the
+stack frame, individual data and constants to be aligned for the maximum
+single data access size for the chosen CPU model.  The default is to
+arrange for 32-bit alignment.  ABI details such as structure layout are
+not affected by these options.
+
+@item -m32-bit
+@itemx -m16-bit
+@itemx -m8-bit
+@opindex m32-bit
+@opindex m16-bit
+@opindex m8-bit
+Similar to the stack- data- and const-align options above, these options
+arrange for stack frame, writable data and constants to all be 32-bit,
+16-bit or 8-bit aligned.  The default is 32-bit alignment.
+
+@item -mno-prologue-epilogue
+@itemx -mprologue-epilogue
+@opindex mno-prologue-epilogue
+@opindex mprologue-epilogue
+With @option{-mno-prologue-epilogue}, the normal function prologue and
+epilogue which set up the stack frame are omitted and no return
+instructions or return sequences are generated in the code.  Use this
+option only together with visual inspection of the compiled code: no
+warnings or errors are generated when call-saved registers must be saved,
+or storage for local variables needs to be allocated.
+
+@item -mno-gotplt
+@itemx -mgotplt
+@opindex mno-gotplt
+@opindex mgotplt
+With @option{-fpic} and @option{-fPIC}, don't generate (do generate)
+instruction sequences that load addresses for functions from the PLT part
+of the GOT rather than (traditional on other architectures) calls to the
+PLT@.  The default is @option{-mgotplt}.
+
+@item -melf
+@opindex melf
+Legacy no-op option only recognized with the cris-axis-elf and
+cris-axis-linux-gnu targets.
+
+@item -mlinux
+@opindex mlinux
+Legacy no-op option only recognized with the cris-axis-linux-gnu target.
+
+@item -sim
+@opindex sim
+This option, recognized for the cris-axis-elf, arranges
+to link with input-output functions from a simulator library.  Code,
+initialized data and zero-initialized data are allocated consecutively.
+
+@item -sim2
+@opindex sim2
+Like @option{-sim}, but pass linker options to locate initialized data at
+0x40000000 and zero-initialized data at 0x80000000.
+@end table
+
+@node CR16 Options
+@subsection CR16 Options
+@cindex CR16 Options
+
+These options are defined specifically for the CR16 ports.
+
+@table @gcctabopt
+
+@item -mmac
+@opindex mmac
+Enable the use of multiply-accumulate instructions. Disabled by default.
+
+@item -mcr16cplus
+@itemx -mcr16c
+@opindex mcr16cplus
+@opindex mcr16c
+Generate code for CR16C or CR16C+ architecture. CR16C+ architecture 
+is default.
+
+@item -msim
+@opindex msim
+Links the library libsim.a which is in compatible with simulator. Applicable
+to ELF compiler only.
+
+@item -mint32
+@opindex mint32
+Choose integer type as 32-bit wide.
+
+@item -mbit-ops
+@opindex mbit-ops
+Generates @code{sbit}/@code{cbit} instructions for bit manipulations.
+
+@item -mdata-model=@var{model}
+@opindex mdata-model
+Choose a data model. The choices for @var{model} are @samp{near},
+@samp{far} or @samp{medium}. @samp{medium} is default.
+However, @samp{far} is not valid with @option{-mcr16c}, as the
+CR16C architecture does not support the far data model.
+@end table
+
+@node Darwin Options
+@subsection Darwin Options
+@cindex Darwin options
+
+These options are defined for all architectures running the Darwin operating
+system.
+
+FSF GCC on Darwin does not create ``fat'' object files; it creates
+an object file for the single architecture that GCC was built to
+target.  Apple's GCC on Darwin does create ``fat'' files if multiple
+@option{-arch} options are used; it does so by running the compiler or
+linker multiple times and joining the results together with
+@file{lipo}.
+
+The subtype of the file created (like @samp{ppc7400} or @samp{ppc970} or
+@samp{i686}) is determined by the flags that specify the ISA
+that GCC is targeting, like @option{-mcpu} or @option{-march}.  The
+@option{-force_cpusubtype_ALL} option can be used to override this.
+
+The Darwin tools vary in their behavior when presented with an ISA
+mismatch.  The assembler, @file{as}, only permits instructions to
+be used that are valid for the subtype of the file it is generating,
+so you cannot put 64-bit instructions in a @samp{ppc750} object file.
+The linker for shared libraries, @file{/usr/bin/libtool}, fails
+and prints an error if asked to create a shared library with a less
+restrictive subtype than its input files (for instance, trying to put
+a @samp{ppc970} object file in a @samp{ppc7400} library).  The linker
+for executables, @command{ld}, quietly gives the executable the most
+restrictive subtype of any of its input files.
+
+@table @gcctabopt
+@item -F@var{dir}
+@opindex F
+Add the framework directory @var{dir} to the head of the list of
+directories to be searched for header files.  These directories are
+interleaved with those specified by @option{-I} options and are
+scanned in a left-to-right order.
+
+A framework directory is a directory with frameworks in it.  A
+framework is a directory with a @file{Headers} and/or
+@file{PrivateHeaders} directory contained directly in it that ends
+in @file{.framework}.  The name of a framework is the name of this
+directory excluding the @file{.framework}.  Headers associated with
+the framework are found in one of those two directories, with
+@file{Headers} being searched first.  A subframework is a framework
+directory that is in a framework's @file{Frameworks} directory.
+Includes of subframework headers can only appear in a header of a
+framework that contains the subframework, or in a sibling subframework
+header.  Two subframeworks are siblings if they occur in the same
+framework.  A subframework should not have the same name as a
+framework; a warning is issued if this is violated.  Currently a
+subframework cannot have subframeworks; in the future, the mechanism
+may be extended to support this.  The standard frameworks can be found
+in @file{/System/Library/Frameworks} and
+@file{/Library/Frameworks}.  An example include looks like
+@code{#include <Framework/header.h>}, where @file{Framework} denotes
+the name of the framework and @file{header.h} is found in the
+@file{PrivateHeaders} or @file{Headers} directory.
+
+@item -iframework@var{dir}
+@opindex iframework
+Like @option{-F} except the directory is a treated as a system
+directory.  The main difference between this @option{-iframework} and
+@option{-F} is that with @option{-iframework} the compiler does not
+warn about constructs contained within header files found via
+@var{dir}.  This option is valid only for the C family of languages.
+
+@item -gused
+@opindex gused
+Emit debugging information for symbols that are used.  For stabs
+debugging format, this enables @option{-feliminate-unused-debug-symbols}.
+This is by default ON@.
+
+@item -gfull
+@opindex gfull
+Emit debugging information for all symbols and types.
+
+@item -mmacosx-version-min=@var{version}
+The earliest version of MacOS X that this executable will run on
+is @var{version}.  Typical values of @var{version} include @code{10.1},
+@code{10.2}, and @code{10.3.9}.
+
+If the compiler was built to use the system's headers by default,
+then the default for this option is the system version on which the
+compiler is running, otherwise the default is to make choices that
+are compatible with as many systems and code bases as possible.
+
+@item -mkernel
+@opindex mkernel
+Enable kernel development mode.  The @option{-mkernel} option sets
+@option{-static}, @option{-fno-common}, @option{-fno-cxa-atexit},
+@option{-fno-exceptions}, @option{-fno-non-call-exceptions},
+@option{-fapple-kext}, @option{-fno-weak} and @option{-fno-rtti} where
+applicable.  This mode also sets @option{-mno-altivec},
+@option{-msoft-float}, @option{-fno-builtin} and
+@option{-mlong-branch} for PowerPC targets.
+
+@item -mone-byte-bool
+@opindex mone-byte-bool
+Override the defaults for @samp{bool} so that @samp{sizeof(bool)==1}.
+By default @samp{sizeof(bool)} is @samp{4} when compiling for
+Darwin/PowerPC and @samp{1} when compiling for Darwin/x86, so this
+option has no effect on x86.
+
+@strong{Warning:} The @option{-mone-byte-bool} switch causes GCC
+to generate code that is not binary compatible with code generated
+without that switch.  Using this switch may require recompiling all
+other modules in a program, including system libraries.  Use this
+switch to conform to a non-default data model.
+
+@item -mfix-and-continue
+@itemx -ffix-and-continue
+@itemx -findirect-data
+@opindex mfix-and-continue
+@opindex ffix-and-continue
+@opindex findirect-data
+Generate code suitable for fast turnaround development, such as to
+allow GDB to dynamically load @code{.o} files into already-running
+programs.  @option{-findirect-data} and @option{-ffix-and-continue}
+are provided for backwards compatibility.
+
+@item -all_load
+@opindex all_load
+Loads all members of static archive libraries.
+See man ld(1) for more information.
+
+@item -arch_errors_fatal
+@opindex arch_errors_fatal
+Cause the errors having to do with files that have the wrong architecture
+to be fatal.
+
+@item -bind_at_load
+@opindex bind_at_load
+Causes the output file to be marked such that the dynamic linker will
+bind all undefined references when the file is loaded or launched.
+
+@item -bundle
+@opindex bundle
+Produce a Mach-o bundle format file.
+See man ld(1) for more information.
+
+@item -bundle_loader @var{executable}
+@opindex bundle_loader
+This option specifies the @var{executable} that will load the build
+output file being linked.  See man ld(1) for more information.
+
+@item -dynamiclib
+@opindex dynamiclib
+When passed this option, GCC produces a dynamic library instead of
+an executable when linking, using the Darwin @file{libtool} command.
+
+@item -force_cpusubtype_ALL
+@opindex force_cpusubtype_ALL
+This causes GCC's output file to have the @var{ALL} subtype, instead of
+one controlled by the @option{-mcpu} or @option{-march} option.
+
+@item -allowable_client  @var{client_name}
+@itemx -client_name
+@itemx -compatibility_version
+@itemx -current_version
+@itemx -dead_strip
+@itemx -dependency-file
+@itemx -dylib_file
+@itemx -dylinker_install_name
+@itemx -dynamic
+@itemx -exported_symbols_list
+@itemx -filelist
+@need 800
+@itemx -flat_namespace
+@itemx -force_flat_namespace
+@itemx -headerpad_max_install_names
+@itemx -image_base
+@itemx -init
+@itemx -install_name
+@itemx -keep_private_externs
+@itemx -multi_module
+@itemx -multiply_defined
+@itemx -multiply_defined_unused
+@need 800
+@itemx -noall_load
+@itemx -no_dead_strip_inits_and_terms
+@itemx -nofixprebinding
+@itemx -nomultidefs
+@itemx -noprebind
+@itemx -noseglinkedit
+@itemx -pagezero_size
+@itemx -prebind
+@itemx -prebind_all_twolevel_modules
+@itemx -private_bundle
+@need 800
+@itemx -read_only_relocs
+@itemx -sectalign
+@itemx -sectobjectsymbols
+@itemx -whyload
+@itemx -seg1addr
+@itemx -sectcreate
+@itemx -sectobjectsymbols
+@itemx -sectorder
+@itemx -segaddr
+@itemx -segs_read_only_addr
+@need 800
+@itemx -segs_read_write_addr
+@itemx -seg_addr_table
+@itemx -seg_addr_table_filename
+@itemx -seglinkedit
+@itemx -segprot
+@itemx -segs_read_only_addr
+@itemx -segs_read_write_addr
+@itemx -single_module
+@itemx -static
+@itemx -sub_library
+@need 800
+@itemx -sub_umbrella
+@itemx -twolevel_namespace
+@itemx -umbrella
+@itemx -undefined
+@itemx -unexported_symbols_list
+@itemx -weak_reference_mismatches
+@itemx -whatsloaded
+@opindex allowable_client
+@opindex client_name
+@opindex compatibility_version
+@opindex current_version
+@opindex dead_strip
+@opindex dependency-file
+@opindex dylib_file
+@opindex dylinker_install_name
+@opindex dynamic
+@opindex exported_symbols_list
+@opindex filelist
+@opindex flat_namespace
+@opindex force_flat_namespace
+@opindex headerpad_max_install_names
+@opindex image_base
+@opindex init
+@opindex install_name
+@opindex keep_private_externs
+@opindex multi_module
+@opindex multiply_defined
+@opindex multiply_defined_unused
+@opindex noall_load
+@opindex no_dead_strip_inits_and_terms
+@opindex nofixprebinding
+@opindex nomultidefs
+@opindex noprebind
+@opindex noseglinkedit
+@opindex pagezero_size
+@opindex prebind
+@opindex prebind_all_twolevel_modules
+@opindex private_bundle
+@opindex read_only_relocs
+@opindex sectalign
+@opindex sectobjectsymbols
+@opindex whyload
+@opindex seg1addr
+@opindex sectcreate
+@opindex sectobjectsymbols
+@opindex sectorder
+@opindex segaddr
+@opindex segs_read_only_addr
+@opindex segs_read_write_addr
+@opindex seg_addr_table
+@opindex seg_addr_table_filename
+@opindex seglinkedit
+@opindex segprot
+@opindex segs_read_only_addr
+@opindex segs_read_write_addr
+@opindex single_module
+@opindex static
+@opindex sub_library
+@opindex sub_umbrella
+@opindex twolevel_namespace
+@opindex umbrella
+@opindex undefined
+@opindex unexported_symbols_list
+@opindex weak_reference_mismatches
+@opindex whatsloaded
+These options are passed to the Darwin linker.  The Darwin linker man page
+describes them in detail.
+@end table
+
+@node DEC Alpha Options
+@subsection DEC Alpha Options
+
+These @samp{-m} options are defined for the DEC Alpha implementations:
+
+@table @gcctabopt
+@item -mno-soft-float
+@itemx -msoft-float
+@opindex mno-soft-float
+@opindex msoft-float
+Use (do not use) the hardware floating-point instructions for
+floating-point operations.  When @option{-msoft-float} is specified,
+functions in @file{libgcc.a} are used to perform floating-point
+operations.  Unless they are replaced by routines that emulate the
+floating-point operations, or compiled in such a way as to call such
+emulations routines, these routines issue floating-point
+operations.   If you are compiling for an Alpha without floating-point
+operations, you must ensure that the library is built so as not to call
+them.
+
+Note that Alpha implementations without floating-point operations are
+required to have floating-point registers.
+
+@item -mfp-reg
+@itemx -mno-fp-regs
+@opindex mfp-reg
+@opindex mno-fp-regs
+Generate code that uses (does not use) the floating-point register set.
+@option{-mno-fp-regs} implies @option{-msoft-float}.  If the floating-point
+register set is not used, floating-point operands are passed in integer
+registers as if they were integers and floating-point results are passed
+in @code{$0} instead of @code{$f0}.  This is a non-standard calling sequence,
+so any function with a floating-point argument or return value called by code
+compiled with @option{-mno-fp-regs} must also be compiled with that
+option.
+
+A typical use of this option is building a kernel that does not use,
+and hence need not save and restore, any floating-point registers.
+
+@item -mieee
+@opindex mieee
+The Alpha architecture implements floating-point hardware optimized for
+maximum performance.  It is mostly compliant with the IEEE floating-point
+standard.  However, for full compliance, software assistance is
+required.  This option generates code fully IEEE-compliant code
+@emph{except} that the @var{inexact-flag} is not maintained (see below).
+If this option is turned on, the preprocessor macro @code{_IEEE_FP} is
+defined during compilation.  The resulting code is less efficient but is
+able to correctly support denormalized numbers and exceptional IEEE
+values such as not-a-number and plus/minus infinity.  Other Alpha
+compilers call this option @option{-ieee_with_no_inexact}.
+
+@item -mieee-with-inexact
+@opindex mieee-with-inexact
+This is like @option{-mieee} except the generated code also maintains
+the IEEE @var{inexact-flag}.  Turning on this option causes the
+generated code to implement fully-compliant IEEE math.  In addition to
+@code{_IEEE_FP}, @code{_IEEE_FP_EXACT} is defined as a preprocessor
+macro.  On some Alpha implementations the resulting code may execute
+significantly slower than the code generated by default.  Since there is
+very little code that depends on the @var{inexact-flag}, you should
+normally not specify this option.  Other Alpha compilers call this
+option @option{-ieee_with_inexact}.
+
+@item -mfp-trap-mode=@var{trap-mode}
+@opindex mfp-trap-mode
+This option controls what floating-point related traps are enabled.
+Other Alpha compilers call this option @option{-fptm @var{trap-mode}}.
+The trap mode can be set to one of four values:
+
+@table @samp
+@item n
+This is the default (normal) setting.  The only traps that are enabled
+are the ones that cannot be disabled in software (e.g., division by zero
+trap).
+
+@item u
+In addition to the traps enabled by @samp{n}, underflow traps are enabled
+as well.
+
+@item su
+Like @samp{u}, but the instructions are marked to be safe for software
+completion (see Alpha architecture manual for details).
+
+@item sui
+Like @samp{su}, but inexact traps are enabled as well.
+@end table
+
+@item -mfp-rounding-mode=@var{rounding-mode}
+@opindex mfp-rounding-mode
+Selects the IEEE rounding mode.  Other Alpha compilers call this option
+@option{-fprm @var{rounding-mode}}.  The @var{rounding-mode} can be one
+of:
+
+@table @samp
+@item n
+Normal IEEE rounding mode.  Floating-point numbers are rounded towards
+the nearest machine number or towards the even machine number in case
+of a tie.
+
+@item m
+Round towards minus infinity.
+
+@item c
+Chopped rounding mode.  Floating-point numbers are rounded towards zero.
+
+@item d
+Dynamic rounding mode.  A field in the floating-point control register
+(@var{fpcr}, see Alpha architecture reference manual) controls the
+rounding mode in effect.  The C library initializes this register for
+rounding towards plus infinity.  Thus, unless your program modifies the
+@var{fpcr}, @samp{d} corresponds to round towards plus infinity.
+@end table
+
+@item -mtrap-precision=@var{trap-precision}
+@opindex mtrap-precision
+In the Alpha architecture, floating-point traps are imprecise.  This
+means without software assistance it is impossible to recover from a
+floating trap and program execution normally needs to be terminated.
+GCC can generate code that can assist operating system trap handlers
+in determining the exact location that caused a floating-point trap.
+Depending on the requirements of an application, different levels of
+precisions can be selected:
+
+@table @samp
+@item p
+Program precision.  This option is the default and means a trap handler
+can only identify which program caused a floating-point exception.
+
+@item f
+Function precision.  The trap handler can determine the function that
+caused a floating-point exception.
+
+@item i
+Instruction precision.  The trap handler can determine the exact
+instruction that caused a floating-point exception.
+@end table
+
+Other Alpha compilers provide the equivalent options called
+@option{-scope_safe} and @option{-resumption_safe}.
+
+@item -mieee-conformant
+@opindex mieee-conformant
+This option marks the generated code as IEEE conformant.  You must not
+use this option unless you also specify @option{-mtrap-precision=i} and either
+@option{-mfp-trap-mode=su} or @option{-mfp-trap-mode=sui}.  Its only effect
+is to emit the line @samp{.eflag 48} in the function prologue of the
+generated assembly file.
+
+@item -mbuild-constants
+@opindex mbuild-constants
+Normally GCC examines a 32- or 64-bit integer constant to
+see if it can construct it from smaller constants in two or three
+instructions.  If it cannot, it outputs the constant as a literal and
+generates code to load it from the data segment at run time.
+
+Use this option to require GCC to construct @emph{all} integer constants
+using code, even if it takes more instructions (the maximum is six).
+
+You typically use this option to build a shared library dynamic
+loader.  Itself a shared library, it must relocate itself in memory
+before it can find the variables and constants in its own data segment.
+
+@item -mbwx
+@itemx -mno-bwx
+@itemx -mcix
+@itemx -mno-cix
+@itemx -mfix
+@itemx -mno-fix
+@itemx -mmax
+@itemx -mno-max
+@opindex mbwx
+@opindex mno-bwx
+@opindex mcix
+@opindex mno-cix
+@opindex mfix
+@opindex mno-fix
+@opindex mmax
+@opindex mno-max
+Indicate whether GCC should generate code to use the optional BWX,
+CIX, FIX and MAX instruction sets.  The default is to use the instruction
+sets supported by the CPU type specified via @option{-mcpu=} option or that
+of the CPU on which GCC was built if none is specified.
+
+@item -mfloat-vax
+@itemx -mfloat-ieee
+@opindex mfloat-vax
+@opindex mfloat-ieee
+Generate code that uses (does not use) VAX F and G floating-point
+arithmetic instead of IEEE single and double precision.
+
+@item -mexplicit-relocs
+@itemx -mno-explicit-relocs
+@opindex mexplicit-relocs
+@opindex mno-explicit-relocs
+Older Alpha assemblers provided no way to generate symbol relocations
+except via assembler macros.  Use of these macros does not allow
+optimal instruction scheduling.  GNU binutils as of version 2.12
+supports a new syntax that allows the compiler to explicitly mark
+which relocations should apply to which instructions.  This option
+is mostly useful for debugging, as GCC detects the capabilities of
+the assembler when it is built and sets the default accordingly.
+
+@item -msmall-data
+@itemx -mlarge-data
+@opindex msmall-data
+@opindex mlarge-data
+When @option{-mexplicit-relocs} is in effect, static data is
+accessed via @dfn{gp-relative} relocations.  When @option{-msmall-data}
+is used, objects 8 bytes long or smaller are placed in a @dfn{small data area}
+(the @code{.sdata} and @code{.sbss} sections) and are accessed via
+16-bit relocations off of the @code{$gp} register.  This limits the
+size of the small data area to 64KB, but allows the variables to be
+directly accessed via a single instruction.
+
+The default is @option{-mlarge-data}.  With this option the data area
+is limited to just below 2GB@.  Programs that require more than 2GB of
+data must use @code{malloc} or @code{mmap} to allocate the data in the
+heap instead of in the program's data segment.
+
+When generating code for shared libraries, @option{-fpic} implies
+@option{-msmall-data} and @option{-fPIC} implies @option{-mlarge-data}.
+
+@item -msmall-text
+@itemx -mlarge-text
+@opindex msmall-text
+@opindex mlarge-text
+When @option{-msmall-text} is used, the compiler assumes that the
+code of the entire program (or shared library) fits in 4MB, and is
+thus reachable with a branch instruction.  When @option{-msmall-data}
+is used, the compiler can assume that all local symbols share the
+same @code{$gp} value, and thus reduce the number of instructions
+required for a function call from 4 to 1.
+
+The default is @option{-mlarge-text}.
+
+@item -mcpu=@var{cpu_type}
+@opindex mcpu
+Set the instruction set and instruction scheduling parameters for
+machine type @var{cpu_type}.  You can specify either the @samp{EV}
+style name or the corresponding chip number.  GCC supports scheduling
+parameters for the EV4, EV5 and EV6 family of processors and
+chooses the default values for the instruction set from the processor
+you specify.  If you do not specify a processor type, GCC defaults
+to the processor on which the compiler was built.
+
+Supported values for @var{cpu_type} are
+
+@table @samp
+@item ev4
+@itemx ev45
+@itemx 21064
+Schedules as an EV4 and has no instruction set extensions.
+
+@item ev5
+@itemx 21164
+Schedules as an EV5 and has no instruction set extensions.
+
+@item ev56
+@itemx 21164a
+Schedules as an EV5 and supports the BWX extension.
+
+@item pca56
+@itemx 21164pc
+@itemx 21164PC
+Schedules as an EV5 and supports the BWX and MAX extensions.
+
+@item ev6
+@itemx 21264
+Schedules as an EV6 and supports the BWX, FIX, and MAX extensions.
+
+@item ev67
+@itemx 21264a
+Schedules as an EV6 and supports the BWX, CIX, FIX, and MAX extensions.
+@end table
+
+Native toolchains also support the value @samp{native},
+which selects the best architecture option for the host processor.
+@option{-mcpu=native} has no effect if GCC does not recognize
+the processor.
+
+@item -mtune=@var{cpu_type}
+@opindex mtune
+Set only the instruction scheduling parameters for machine type
+@var{cpu_type}.  The instruction set is not changed.
+
+Native toolchains also support the value @samp{native},
+which selects the best architecture option for the host processor.
+@option{-mtune=native} has no effect if GCC does not recognize
+the processor.
+
+@item -mmemory-latency=@var{time}
+@opindex mmemory-latency
+Sets the latency the scheduler should assume for typical memory
+references as seen by the application.  This number is highly
+dependent on the memory access patterns used by the application
+and the size of the external cache on the machine.
+
+Valid options for @var{time} are
+
+@table @samp
+@item @var{number}
+A decimal number representing clock cycles.
+
+@item L1
+@itemx L2
+@itemx L3
+@itemx main
+The compiler contains estimates of the number of clock cycles for
+``typical'' EV4 & EV5 hardware for the Level 1, 2 & 3 caches
+(also called Dcache, Scache, and Bcache), as well as to main memory.
+Note that L3 is only valid for EV5.
+
+@end table
+@end table
+
+@node FR30 Options
+@subsection FR30 Options
+@cindex FR30 Options
+
+These options are defined specifically for the FR30 port.
+
+@table @gcctabopt
+
+@item -msmall-model
+@opindex msmall-model
+Use the small address space model.  This can produce smaller code, but
+it does assume that all symbolic values and addresses fit into a
+20-bit range.
+
+@item -mno-lsim
+@opindex mno-lsim
+Assume that runtime support has been provided and so there is no need
+to include the simulator library (@file{libsim.a}) on the linker
+command line.
+
+@end table
+
+@node FRV Options
+@subsection FRV Options
+@cindex FRV Options
+
+@table @gcctabopt
+@item -mgpr-32
+@opindex mgpr-32
+
+Only use the first 32 general-purpose registers.
+
+@item -mgpr-64
+@opindex mgpr-64
+
+Use all 64 general-purpose registers.
+
+@item -mfpr-32
+@opindex mfpr-32
+
+Use only the first 32 floating-point registers.
+
+@item -mfpr-64
+@opindex mfpr-64
+
+Use all 64 floating-point registers.
+
+@item -mhard-float
+@opindex mhard-float
+
+Use hardware instructions for floating-point operations.
+
+@item -msoft-float
+@opindex msoft-float
+
+Use library routines for floating-point operations.
+
+@item -malloc-cc
+@opindex malloc-cc
+
+Dynamically allocate condition code registers.
+
+@item -mfixed-cc
+@opindex mfixed-cc
+
+Do not try to dynamically allocate condition code registers, only
+use @code{icc0} and @code{fcc0}.
+
+@item -mdword
+@opindex mdword
+
+Change ABI to use double word insns.
+
+@item -mno-dword
+@opindex mno-dword
+
+Do not use double word instructions.
+
+@item -mdouble
+@opindex mdouble
+
+Use floating-point double instructions.
+
+@item -mno-double
+@opindex mno-double
+
+Do not use floating-point double instructions.
+
+@item -mmedia
+@opindex mmedia
+
+Use media instructions.
+
+@item -mno-media
+@opindex mno-media
+
+Do not use media instructions.
+
+@item -mmuladd
+@opindex mmuladd
+
+Use multiply and add/subtract instructions.
+
+@item -mno-muladd
+@opindex mno-muladd
+
+Do not use multiply and add/subtract instructions.
+
+@item -mfdpic
+@opindex mfdpic
+
+Select the FDPIC ABI, which uses function descriptors to represent
+pointers to functions.  Without any PIC/PIE-related options, it
+implies @option{-fPIE}.  With @option{-fpic} or @option{-fpie}, it
+assumes GOT entries and small data are within a 12-bit range from the
+GOT base address; with @option{-fPIC} or @option{-fPIE}, GOT offsets
+are computed with 32 bits.
+With a @samp{bfin-elf} target, this option implies @option{-msim}.
+
+@item -minline-plt
+@opindex minline-plt
+
+Enable inlining of PLT entries in function calls to functions that are
+not known to bind locally.  It has no effect without @option{-mfdpic}.
+It's enabled by default if optimizing for speed and compiling for
+shared libraries (i.e., @option{-fPIC} or @option{-fpic}), or when an
+optimization option such as @option{-O3} or above is present in the
+command line.
+
+@item -mTLS
+@opindex mTLS
+
+Assume a large TLS segment when generating thread-local code.
+
+@item -mtls
+@opindex mtls
+
+Do not assume a large TLS segment when generating thread-local code.
+
+@item -mgprel-ro
+@opindex mgprel-ro
+
+Enable the use of @code{GPREL} relocations in the FDPIC ABI for data
+that is known to be in read-only sections.  It's enabled by default,
+except for @option{-fpic} or @option{-fpie}: even though it may help
+make the global offset table smaller, it trades 1 instruction for 4.
+With @option{-fPIC} or @option{-fPIE}, it trades 3 instructions for 4,
+one of which may be shared by multiple symbols, and it avoids the need
+for a GOT entry for the referenced symbol, so it's more likely to be a
+win.  If it is not, @option{-mno-gprel-ro} can be used to disable it.
+
+@item -multilib-library-pic
+@opindex multilib-library-pic
+
+Link with the (library, not FD) pic libraries.  It's implied by
+@option{-mlibrary-pic}, as well as by @option{-fPIC} and
+@option{-fpic} without @option{-mfdpic}.  You should never have to use
+it explicitly.
+
+@item -mlinked-fp
+@opindex mlinked-fp
+
+Follow the EABI requirement of always creating a frame pointer whenever
+a stack frame is allocated.  This option is enabled by default and can
+be disabled with @option{-mno-linked-fp}.
+
+@item -mlong-calls
+@opindex mlong-calls
+
+Use indirect addressing to call functions outside the current
+compilation unit.  This allows the functions to be placed anywhere
+within the 32-bit address space.
+
+@item -malign-labels
+@opindex malign-labels
+
+Try to align labels to an 8-byte boundary by inserting NOPs into the
+previous packet.  This option only has an effect when VLIW packing
+is enabled.  It doesn't create new packets; it merely adds NOPs to
+existing ones.
+
+@item -mlibrary-pic
+@opindex mlibrary-pic
+
+Generate position-independent EABI code.
+
+@item -macc-4
+@opindex macc-4
+
+Use only the first four media accumulator registers.
+
+@item -macc-8
+@opindex macc-8
+
+Use all eight media accumulator registers.
+
+@item -mpack
+@opindex mpack
+
+Pack VLIW instructions.
+
+@item -mno-pack
+@opindex mno-pack
+
+Do not pack VLIW instructions.
+
+@item -mno-eflags
+@opindex mno-eflags
+
+Do not mark ABI switches in e_flags.
+
+@item -mcond-move
+@opindex mcond-move
+
+Enable the use of conditional-move instructions (default).
+
+This switch is mainly for debugging the compiler and will likely be removed
+in a future version.
+
+@item -mno-cond-move
+@opindex mno-cond-move
+
+Disable the use of conditional-move instructions.
+
+This switch is mainly for debugging the compiler and will likely be removed
+in a future version.
+
+@item -mscc
+@opindex mscc
+
+Enable the use of conditional set instructions (default).
+
+This switch is mainly for debugging the compiler and will likely be removed
+in a future version.
+
+@item -mno-scc
+@opindex mno-scc
+
+Disable the use of conditional set instructions.
+
+This switch is mainly for debugging the compiler and will likely be removed
+in a future version.
+
+@item -mcond-exec
+@opindex mcond-exec
+
+Enable the use of conditional execution (default).
+
+This switch is mainly for debugging the compiler and will likely be removed
+in a future version.
+
+@item -mno-cond-exec
+@opindex mno-cond-exec
+
+Disable the use of conditional execution.
+
+This switch is mainly for debugging the compiler and will likely be removed
+in a future version.
+
+@item -mvliw-branch
+@opindex mvliw-branch
+
+Run a pass to pack branches into VLIW instructions (default).
+
+This switch is mainly for debugging the compiler and will likely be removed
+in a future version.
+
+@item -mno-vliw-branch
+@opindex mno-vliw-branch
+
+Do not run a pass to pack branches into VLIW instructions.
+
+This switch is mainly for debugging the compiler and will likely be removed
+in a future version.
+
+@item -mmulti-cond-exec
+@opindex mmulti-cond-exec
+
+Enable optimization of @code{&&} and @code{||} in conditional execution
+(default).
+
+This switch is mainly for debugging the compiler and will likely be removed
+in a future version.
+
+@item -mno-multi-cond-exec
+@opindex mno-multi-cond-exec
+
+Disable optimization of @code{&&} and @code{||} in conditional execution.
+
+This switch is mainly for debugging the compiler and will likely be removed
+in a future version.
+
+@item -mnested-cond-exec
+@opindex mnested-cond-exec
+
+Enable nested conditional execution optimizations (default).
+
+This switch is mainly for debugging the compiler and will likely be removed
+in a future version.
+
+@item -mno-nested-cond-exec
+@opindex mno-nested-cond-exec
+
+Disable nested conditional execution optimizations.
+
+This switch is mainly for debugging the compiler and will likely be removed
+in a future version.
+
+@item -moptimize-membar
+@opindex moptimize-membar
+
+This switch removes redundant @code{membar} instructions from the
+compiler-generated code.  It is enabled by default.
+
+@item -mno-optimize-membar
+@opindex mno-optimize-membar
+
+This switch disables the automatic removal of redundant @code{membar}
+instructions from the generated code.
+
+@item -mtomcat-stats
+@opindex mtomcat-stats
+
+Cause gas to print out tomcat statistics.
+
+@item -mcpu=@var{cpu}
+@opindex mcpu
+
+Select the processor type for which to generate code.  Possible values are
+@samp{frv}, @samp{fr550}, @samp{tomcat}, @samp{fr500}, @samp{fr450},
+@samp{fr405}, @samp{fr400}, @samp{fr300} and @samp{simple}.
+
+@end table
+
+@node GNU/Linux Options
+@subsection GNU/Linux Options
+
+These @samp{-m} options are defined for GNU/Linux targets:
+
+@table @gcctabopt
+@item -mglibc
+@opindex mglibc
+Use the GNU C library.  This is the default except
+on @samp{*-*-linux-*uclibc*} and @samp{*-*-linux-*android*} targets.
+
+@item -muclibc
+@opindex muclibc
+Use uClibc C library.  This is the default on
+@samp{*-*-linux-*uclibc*} targets.
+
+@item -mbionic
+@opindex mbionic
+Use Bionic C library.  This is the default on
+@samp{*-*-linux-*android*} targets.
+
+@item -mandroid
+@opindex mandroid
+Compile code compatible with Android platform.  This is the default on
+@samp{*-*-linux-*android*} targets.
+
+When compiling, this option enables @option{-mbionic}, @option{-fPIC},
+@option{-fno-exceptions} and @option{-fno-rtti} by default.  When linking,
+this option makes the GCC driver pass Android-specific options to the linker.
+Finally, this option causes the preprocessor macro @code{__ANDROID__}
+to be defined.
+
+@item -tno-android-cc
+@opindex tno-android-cc
+Disable compilation effects of @option{-mandroid}, i.e., do not enable
+@option{-mbionic}, @option{-fPIC}, @option{-fno-exceptions} and
+@option{-fno-rtti} by default.
+
+@item -tno-android-ld
+@opindex tno-android-ld
+Disable linking effects of @option{-mandroid}, i.e., pass standard Linux
+linking options to the linker.
+
+@end table
+
+@node H8/300 Options
+@subsection H8/300 Options
+
+These @samp{-m} options are defined for the H8/300 implementations:
+
+@table @gcctabopt
+@item -mrelax
+@opindex mrelax
+Shorten some address references at link time, when possible; uses the
+linker option @option{-relax}.  @xref{H8/300,, @code{ld} and the H8/300,
+ld, Using ld}, for a fuller description.
+
+@item -mh
+@opindex mh
+Generate code for the H8/300H@.
+
+@item -ms
+@opindex ms
+Generate code for the H8S@.
+
+@item -mn
+@opindex mn
+Generate code for the H8S and H8/300H in the normal mode.  This switch
+must be used either with @option{-mh} or @option{-ms}.
+
+@item -ms2600
+@opindex ms2600
+Generate code for the H8S/2600.  This switch must be used with @option{-ms}.
+
+@item -mexr
+@opindex mexr
+Extended registers are stored on stack before execution of function
+with monitor attribute. Default option is @option{-mexr}.
+This option is valid only for H8S targets.
+
+@item -mno-exr
+@opindex mno-exr
+Extended registers are not stored on stack before execution of function 
+with monitor attribute. Default option is @option{-mno-exr}. 
+This option is valid only for H8S targets.
+
+@item -mint32
+@opindex mint32
+Make @code{int} data 32 bits by default.
+
+@item -malign-300
+@opindex malign-300
+On the H8/300H and H8S, use the same alignment rules as for the H8/300.
+The default for the H8/300H and H8S is to align longs and floats on
+4-byte boundaries.
+@option{-malign-300} causes them to be aligned on 2-byte boundaries.
+This option has no effect on the H8/300.
+@end table
+
+@node HPPA Options
+@subsection HPPA Options
+@cindex HPPA Options
+
+These @samp{-m} options are defined for the HPPA family of computers:
+
+@table @gcctabopt
+@item -march=@var{architecture-type}
+@opindex march
+Generate code for the specified architecture.  The choices for
+@var{architecture-type} are @samp{1.0} for PA 1.0, @samp{1.1} for PA
+1.1, and @samp{2.0} for PA 2.0 processors.  Refer to
+@file{/usr/lib/sched.models} on an HP-UX system to determine the proper
+architecture option for your machine.  Code compiled for lower numbered
+architectures runs on higher numbered architectures, but not the
+other way around.
+
+@item -mpa-risc-1-0
+@itemx -mpa-risc-1-1
+@itemx -mpa-risc-2-0
+@opindex mpa-risc-1-0
+@opindex mpa-risc-1-1
+@opindex mpa-risc-2-0
+Synonyms for @option{-march=1.0}, @option{-march=1.1}, and @option{-march=2.0} respectively.
+
+@item -mbig-switch
+@opindex mbig-switch
+Generate code suitable for big switch tables.  Use this option only if
+the assembler/linker complain about out-of-range branches within a switch
+table.
+
+@item -mjump-in-delay
+@opindex mjump-in-delay
+Fill delay slots of function calls with unconditional jump instructions
+by modifying the return pointer for the function call to be the target
+of the conditional jump.
+
+@item -mdisable-fpregs
+@opindex mdisable-fpregs
+Prevent floating-point registers from being used in any manner.  This is
+necessary for compiling kernels that perform lazy context switching of
+floating-point registers.  If you use this option and attempt to perform
+floating-point operations, the compiler aborts.
+
+@item -mdisable-indexing
+@opindex mdisable-indexing
+Prevent the compiler from using indexing address modes.  This avoids some
+rather obscure problems when compiling MIG generated code under MACH@.
+
+@item -mno-space-regs
+@opindex mno-space-regs
+Generate code that assumes the target has no space registers.  This allows
+GCC to generate faster indirect calls and use unscaled index address modes.
+
+Such code is suitable for level 0 PA systems and kernels.
+
+@item -mfast-indirect-calls
+@opindex mfast-indirect-calls
+Generate code that assumes calls never cross space boundaries.  This
+allows GCC to emit code that performs faster indirect calls.
+
+This option does not work in the presence of shared libraries or nested
+functions.
+
+@item -mfixed-range=@var{register-range}
+@opindex mfixed-range
+Generate code treating the given register range as fixed registers.
+A fixed register is one that the register allocator cannot use.  This is
+useful when compiling kernel code.  A register range is specified as
+two registers separated by a dash.  Multiple register ranges can be
+specified separated by a comma.
+
+@item -mlong-load-store
+@opindex mlong-load-store
+Generate 3-instruction load and store sequences as sometimes required by
+the HP-UX 10 linker.  This is equivalent to the @samp{+k} option to
+the HP compilers.
+
+@item -mportable-runtime
+@opindex mportable-runtime
+Use the portable calling conventions proposed by HP for ELF systems.
+
+@item -mgas
+@opindex mgas
+Enable the use of assembler directives only GAS understands.
+
+@item -mschedule=@var{cpu-type}
+@opindex mschedule
+Schedule code according to the constraints for the machine type
+@var{cpu-type}.  The choices for @var{cpu-type} are @samp{700}
+@samp{7100}, @samp{7100LC}, @samp{7200}, @samp{7300} and @samp{8000}.  Refer
+to @file{/usr/lib/sched.models} on an HP-UX system to determine the
+proper scheduling option for your machine.  The default scheduling is
+@samp{8000}.
+
+@item -mlinker-opt
+@opindex mlinker-opt
+Enable the optimization pass in the HP-UX linker.  Note this makes symbolic
+debugging impossible.  It also triggers a bug in the HP-UX 8 and HP-UX 9
+linkers in which they give bogus error messages when linking some programs.
+
+@item -msoft-float
+@opindex msoft-float
+Generate output containing library calls for floating point.
+@strong{Warning:} the requisite libraries are not available for all HPPA
+targets.  Normally the facilities of the machine's usual C compiler are
+used, but this cannot be done directly in cross-compilation.  You must make
+your own arrangements to provide suitable library functions for
+cross-compilation.
+
+@option{-msoft-float} changes the calling convention in the output file;
+therefore, it is only useful if you compile @emph{all} of a program with
+this option.  In particular, you need to compile @file{libgcc.a}, the
+library that comes with GCC, with @option{-msoft-float} in order for
+this to work.
+
+@item -msio
+@opindex msio
+Generate the predefine, @code{_SIO}, for server IO@.  The default is
+@option{-mwsio}.  This generates the predefines, @code{__hp9000s700},
+@code{__hp9000s700__} and @code{_WSIO}, for workstation IO@.  These
+options are available under HP-UX and HI-UX@.
+
+@item -mgnu-ld
+@opindex mgnu-ld
+Use options specific to GNU @command{ld}.
+This passes @option{-shared} to @command{ld} when
+building a shared library.  It is the default when GCC is configured,
+explicitly or implicitly, with the GNU linker.  This option does not
+affect which @command{ld} is called; it only changes what parameters
+are passed to that @command{ld}.
+The @command{ld} that is called is determined by the
+@option{--with-ld} configure option, GCC's program search path, and
+finally by the user's @env{PATH}.  The linker used by GCC can be printed
+using @samp{which `gcc -print-prog-name=ld`}.  This option is only available
+on the 64-bit HP-UX GCC, i.e.@: configured with @samp{hppa*64*-*-hpux*}.
+
+@item -mhp-ld
+@opindex mhp-ld
+Use options specific to HP @command{ld}.
+This passes @option{-b} to @command{ld} when building
+a shared library and passes @option{+Accept TypeMismatch} to @command{ld} on all
+links.  It is the default when GCC is configured, explicitly or
+implicitly, with the HP linker.  This option does not affect
+which @command{ld} is called; it only changes what parameters are passed to that
+@command{ld}.
+The @command{ld} that is called is determined by the @option{--with-ld}
+configure option, GCC's program search path, and finally by the user's
+@env{PATH}.  The linker used by GCC can be printed using @samp{which
+`gcc -print-prog-name=ld`}.  This option is only available on the 64-bit
+HP-UX GCC, i.e.@: configured with @samp{hppa*64*-*-hpux*}.
+
+@item -mlong-calls
+@opindex mno-long-calls
+Generate code that uses long call sequences.  This ensures that a call
+is always able to reach linker generated stubs.  The default is to generate
+long calls only when the distance from the call site to the beginning
+of the function or translation unit, as the case may be, exceeds a
+predefined limit set by the branch type being used.  The limits for
+normal calls are 7,600,000 and 240,000 bytes, respectively for the
+PA 2.0 and PA 1.X architectures.  Sibcalls are always limited at
+240,000 bytes.
+
+Distances are measured from the beginning of functions when using the
+@option{-ffunction-sections} option, or when using the @option{-mgas}
+and @option{-mno-portable-runtime} options together under HP-UX with
+the SOM linker.
+
+It is normally not desirable to use this option as it degrades
+performance.  However, it may be useful in large applications,
+particularly when partial linking is used to build the application.
+
+The types of long calls used depends on the capabilities of the
+assembler and linker, and the type of code being generated.  The
+impact on systems that support long absolute calls, and long pic
+symbol-difference or pc-relative calls should be relatively small.
+However, an indirect call is used on 32-bit ELF systems in pic code
+and it is quite long.
+
+@item -munix=@var{unix-std}
+@opindex march
+Generate compiler predefines and select a startfile for the specified
+UNIX standard.  The choices for @var{unix-std} are @samp{93}, @samp{95}
+and @samp{98}.  @samp{93} is supported on all HP-UX versions.  @samp{95}
+is available on HP-UX 10.10 and later.  @samp{98} is available on HP-UX
+11.11 and later.  The default values are @samp{93} for HP-UX 10.00,
+@samp{95} for HP-UX 10.10 though to 11.00, and @samp{98} for HP-UX 11.11
+and later.
+
+@option{-munix=93} provides the same predefines as GCC 3.3 and 3.4.
+@option{-munix=95} provides additional predefines for @code{XOPEN_UNIX}
+and @code{_XOPEN_SOURCE_EXTENDED}, and the startfile @file{unix95.o}.
+@option{-munix=98} provides additional predefines for @code{_XOPEN_UNIX},
+@code{_XOPEN_SOURCE_EXTENDED}, @code{_INCLUDE__STDC_A1_SOURCE} and
+@code{_INCLUDE_XOPEN_SOURCE_500}, and the startfile @file{unix98.o}.
+
+It is @emph{important} to note that this option changes the interfaces
+for various library routines.  It also affects the operational behavior
+of the C library.  Thus, @emph{extreme} care is needed in using this
+option.
+
+Library code that is intended to operate with more than one UNIX
+standard must test, set and restore the variable @var{__xpg4_extended_mask}
+as appropriate.  Most GNU software doesn't provide this capability.
+
+@item -nolibdld
+@opindex nolibdld
+Suppress the generation of link options to search libdld.sl when the
+@option{-static} option is specified on HP-UX 10 and later.
+
+@item -static
+@opindex static
+The HP-UX implementation of setlocale in libc has a dependency on
+libdld.sl.  There isn't an archive version of libdld.sl.  Thus,
+when the @option{-static} option is specified, special link options
+are needed to resolve this dependency.
+
+On HP-UX 10 and later, the GCC driver adds the necessary options to
+link with libdld.sl when the @option{-static} option is specified.
+This causes the resulting binary to be dynamic.  On the 64-bit port,
+the linkers generate dynamic binaries by default in any case.  The
+@option{-nolibdld} option can be used to prevent the GCC driver from
+adding these link options.
+
+@item -threads
+@opindex threads
+Add support for multithreading with the @dfn{dce thread} library
+under HP-UX@.  This option sets flags for both the preprocessor and
+linker.
+@end table
+
+@node i386 and x86-64 Options
+@subsection Intel 386 and AMD x86-64 Options
+@cindex i386 Options
+@cindex x86-64 Options
+@cindex Intel 386 Options
+@cindex AMD x86-64 Options
+
+These @samp{-m} options are defined for the i386 and x86-64 family of
+computers:
+
+@table @gcctabopt
+
+@item -march=@var{cpu-type}
+@opindex march
+Generate instructions for the machine type @var{cpu-type}.  In contrast to
+@option{-mtune=@var{cpu-type}}, which merely tunes the generated code 
+for the specified @var{cpu-type}, @option{-march=@var{cpu-type}} allows GCC
+to generate code that may not run at all on processors other than the one
+indicated.  Specifying @option{-march=@var{cpu-type}} implies 
+@option{-mtune=@var{cpu-type}}.
+
+The choices for @var{cpu-type} are:
+
+@table @samp
+@item native
+This selects the CPU to generate code for at compilation time by determining
+the processor type of the compiling machine.  Using @option{-march=native}
+enables all instruction subsets supported by the local machine (hence
+the result might not run on different machines).  Using @option{-mtune=native}
+produces code optimized for the local machine under the constraints
+of the selected instruction set.  
+
+@item i386
+Original Intel i386 CPU@.
+
+@item i486
+Intel i486 CPU@.  (No scheduling is implemented for this chip.)
+
+@item i586
+@itemx pentium
+Intel Pentium CPU with no MMX support.
+
+@item pentium-mmx
+Intel Pentium MMX CPU, based on Pentium core with MMX instruction set support.
+
+@item pentiumpro
+Intel Pentium Pro CPU@.
+
+@item i686
+When used with @option{-march}, the Pentium Pro
+instruction set is used, so the code runs on all i686 family chips.
+When used with @option{-mtune}, it has the same meaning as @samp{generic}.
+
+@item pentium2
+Intel Pentium II CPU, based on Pentium Pro core with MMX instruction set
+support.
+
+@item pentium3
+@itemx pentium3m
+Intel Pentium III CPU, based on Pentium Pro core with MMX and SSE instruction
+set support.
+
+@item pentium-m
+Intel Pentium M; low-power version of Intel Pentium III CPU
+with MMX, SSE and SSE2 instruction set support.  Used by Centrino notebooks.
+
+@item pentium4
+@itemx pentium4m
+Intel Pentium 4 CPU with MMX, SSE and SSE2 instruction set support.
+
+@item prescott
+Improved version of Intel Pentium 4 CPU with MMX, SSE, SSE2 and SSE3 instruction
+set support.
+
+@item nocona
+Improved version of Intel Pentium 4 CPU with 64-bit extensions, MMX, SSE,
+SSE2 and SSE3 instruction set support.
+
+@item core2
+Intel Core 2 CPU with 64-bit extensions, MMX, SSE, SSE2, SSE3 and SSSE3
+instruction set support.
+
+@item corei7
+Intel Core i7 CPU with 64-bit extensions, MMX, SSE, SSE2, SSE3, SSSE3, SSE4.1
+and SSE4.2 instruction set support.
+
+@item corei7-avx
+Intel Core i7 CPU with 64-bit extensions, MMX, SSE, SSE2, SSE3, SSSE3,
+SSE4.1, SSE4.2, AVX, AES and PCLMUL instruction set support.
+
+@item core-avx-i
+Intel Core CPU with 64-bit extensions, MMX, SSE, SSE2, SSE3, SSSE3,
+SSE4.1, SSE4.2, AVX, AES, PCLMUL, FSGSBASE, RDRND and F16C instruction
+set support.
+
+@item core-avx2
+Intel Core CPU with 64-bit extensions, MOVBE, MMX, SSE, SSE2, SSE3, SSSE3,
+SSE4.1, SSE4.2, AVX, AVX2, AES, PCLMUL, FSGSBASE, RDRND, FMA, BMI, BMI2
+and F16C instruction set support.
+
+@item atom
+Intel Atom CPU with 64-bit extensions, MOVBE, MMX, SSE, SSE2, SSE3 and SSSE3
+instruction set support.
+
+@item k6
+AMD K6 CPU with MMX instruction set support.
+
+@item k6-2
+@itemx k6-3
+Improved versions of AMD K6 CPU with MMX and 3DNow!@: instruction set support.
+
+@item athlon
+@itemx athlon-tbird
+AMD Athlon CPU with MMX, 3dNOW!, enhanced 3DNow!@: and SSE prefetch instructions
+support.
+
+@item athlon-4
+@itemx athlon-xp
+@itemx athlon-mp
+Improved AMD Athlon CPU with MMX, 3DNow!, enhanced 3DNow!@: and full SSE
+instruction set support.
+
+@item k8
+@itemx opteron
+@itemx athlon64
+@itemx athlon-fx
+Processors based on the AMD K8 core with x86-64 instruction set support,
+including the AMD Opteron, Athlon 64, and Athlon 64 FX processors.
+(This supersets MMX, SSE, SSE2, 3DNow!, enhanced 3DNow!@: and 64-bit
+instruction set extensions.)
+
+@item k8-sse3
+@itemx opteron-sse3
+@itemx athlon64-sse3
+Improved versions of AMD K8 cores with SSE3 instruction set support.
+
+@item amdfam10
+@itemx barcelona
+CPUs based on AMD Family 10h cores with x86-64 instruction set support.  (This
+supersets MMX, SSE, SSE2, SSE3, SSE4A, 3DNow!, enhanced 3DNow!, ABM and 64-bit
+instruction set extensions.)
+
+@item bdver1
+CPUs based on AMD Family 15h cores with x86-64 instruction set support.  (This
+supersets FMA4, AVX, XOP, LWP, AES, PCL_MUL, CX16, MMX, SSE, SSE2, SSE3, SSE4A,
+SSSE3, SSE4.1, SSE4.2, ABM and 64-bit instruction set extensions.)
+@item bdver2
+AMD Family 15h core based CPUs with x86-64 instruction set support.  (This
+supersets BMI, TBM, F16C, FMA, AVX, XOP, LWP, AES, PCL_MUL, CX16, MMX, SSE,
+SSE2, SSE3, SSE4A, SSSE3, SSE4.1, SSE4.2, ABM and 64-bit instruction set 
+extensions.)
+@item bdver3
+AMD Family 15h core based CPUs with x86-64 instruction set support.  (This
+supersets BMI, TBM, F16C, FMA, AVX, XOP, LWP, AES, PCL_MUL, CX16, MMX, SSE,
+SSE2, SSE3, SSE4A, SSSE3, SSE4.1, SSE4.2, ABM and 64-bit instruction set 
+extensions.
+
+@item btver1
+CPUs based on AMD Family 14h cores with x86-64 instruction set support.  (This
+supersets MMX, SSE, SSE2, SSE3, SSSE3, SSE4A, CX16, ABM and 64-bit
+instruction set extensions.)
+
+@item btver2
+CPUs based on AMD Family 16h cores with x86-64 instruction set support. This
+includes MOVBE, F16C, BMI, AVX, PCL_MUL, AES, SSE4.2, SSE4.1, CX16, ABM,
+SSE4A, SSSE3, SSE3, SSE2, SSE, MMX and 64-bit instruction set extensions.
+
+@item winchip-c6
+IDT WinChip C6 CPU, dealt in same way as i486 with additional MMX instruction
+set support.
+
+@item winchip2
+IDT WinChip 2 CPU, dealt in same way as i486 with additional MMX and 3DNow!@:
+instruction set support.
+
+@item c3
+VIA C3 CPU with MMX and 3DNow!@: instruction set support.  (No scheduling is
+implemented for this chip.)
+
+@item c3-2
+VIA C3-2 (Nehemiah/C5XL) CPU with MMX and SSE instruction set support.
+(No scheduling is
+implemented for this chip.)
+
+@item geode
+AMD Geode embedded processor with MMX and 3DNow!@: instruction set support.
+@end table
+
+@item -mtune=@var{cpu-type}
+@opindex mtune
+Tune to @var{cpu-type} everything applicable about the generated code, except
+for the ABI and the set of available instructions.  
+While picking a specific @var{cpu-type} schedules things appropriately
+for that particular chip, the compiler does not generate any code that
+cannot run on the default machine type unless you use a
+@option{-march=@var{cpu-type}} option.
+For example, if GCC is configured for i686-pc-linux-gnu
+then @option{-mtune=pentium4} generates code that is tuned for Pentium 4
+but still runs on i686 machines.
+
+The choices for @var{cpu-type} are the same as for @option{-march}.
+In addition, @option{-mtune} supports an extra choice for @var{cpu-type}:
+
+@table @samp
+@item generic
+Produce code optimized for the most common IA32/@/AMD64/@/EM64T processors.
+If you know the CPU on which your code will run, then you should use
+the corresponding @option{-mtune} or @option{-march} option instead of
+@option{-mtune=generic}.  But, if you do not know exactly what CPU users
+of your application will have, then you should use this option.
+
+As new processors are deployed in the marketplace, the behavior of this
+option will change.  Therefore, if you upgrade to a newer version of
+GCC, code generation controlled by this option will change to reflect
+the processors
+that are most common at the time that version of GCC is released.
+
+There is no @option{-march=generic} option because @option{-march}
+indicates the instruction set the compiler can use, and there is no
+generic instruction set applicable to all processors.  In contrast,
+@option{-mtune} indicates the processor (or, in this case, collection of
+processors) for which the code is optimized.
+@end table
+
+@item -mcpu=@var{cpu-type}
+@opindex mcpu
+A deprecated synonym for @option{-mtune}.
+
+@item -mfpmath=@var{unit}
+@opindex mfpmath
+Generate floating-point arithmetic for selected unit @var{unit}.  The choices
+for @var{unit} are:
+
+@table @samp
+@item 387
+Use the standard 387 floating-point coprocessor present on the majority of chips and
+emulated otherwise.  Code compiled with this option runs almost everywhere.
+The temporary results are computed in 80-bit precision instead of the precision
+specified by the type, resulting in slightly different results compared to most
+of other chips.  See @option{-ffloat-store} for more detailed description.
+
+This is the default choice for i386 compiler.
+
+@item sse
+Use scalar floating-point instructions present in the SSE instruction set.
+This instruction set is supported by Pentium III and newer chips,
+and in the AMD line
+by Athlon-4, Athlon XP and Athlon MP chips.  The earlier version of the SSE
+instruction set supports only single-precision arithmetic, thus the double and
+extended-precision arithmetic are still done using 387.  A later version, present
+only in Pentium 4 and AMD x86-64 chips, supports double-precision
+arithmetic too.
+
+For the i386 compiler, you must use @option{-march=@var{cpu-type}}, @option{-msse}
+or @option{-msse2} switches to enable SSE extensions and make this option
+effective.  For the x86-64 compiler, these extensions are enabled by default.
+
+The resulting code should be considerably faster in the majority of cases and avoid
+the numerical instability problems of 387 code, but may break some existing
+code that expects temporaries to be 80 bits.
+
+This is the default choice for the x86-64 compiler.
+
+@item sse,387
+@itemx sse+387
+@itemx both
+Attempt to utilize both instruction sets at once.  This effectively doubles the
+amount of available registers, and on chips with separate execution units for
+387 and SSE the execution resources too.  Use this option with care, as it is
+still experimental, because the GCC register allocator does not model separate
+functional units well, resulting in unstable performance.
+@end table
+
+@item -masm=@var{dialect}
+@opindex masm=@var{dialect}
+Output assembly instructions using selected @var{dialect}.  Supported
+choices are @samp{intel} or @samp{att} (the default).  Darwin does
+not support @samp{intel}.
+
+@item -mieee-fp
+@itemx -mno-ieee-fp
+@opindex mieee-fp
+@opindex mno-ieee-fp
+Control whether or not the compiler uses IEEE floating-point
+comparisons.  These correctly handle the case where the result of a
+comparison is unordered.
+
+@item -msoft-float
+@opindex msoft-float
+Generate output containing library calls for floating point.
+
+@strong{Warning:} the requisite libraries are not part of GCC@.
+Normally the facilities of the machine's usual C compiler are used, but
+this can't be done directly in cross-compilation.  You must make your
+own arrangements to provide suitable library functions for
+cross-compilation.
+
+On machines where a function returns floating-point results in the 80387
+register stack, some floating-point opcodes may be emitted even if
+@option{-msoft-float} is used.
+
+@item -mno-fp-ret-in-387
+@opindex mno-fp-ret-in-387
+Do not use the FPU registers for return values of functions.
+
+The usual calling convention has functions return values of types
+@code{float} and @code{double} in an FPU register, even if there
+is no FPU@.  The idea is that the operating system should emulate
+an FPU@.
+
+The option @option{-mno-fp-ret-in-387} causes such values to be returned
+in ordinary CPU registers instead.
+
+@item -mno-fancy-math-387
+@opindex mno-fancy-math-387
+Some 387 emulators do not support the @code{sin}, @code{cos} and
+@code{sqrt} instructions for the 387.  Specify this option to avoid
+generating those instructions.  This option is the default on FreeBSD,
+OpenBSD and NetBSD@.  This option is overridden when @option{-march}
+indicates that the target CPU always has an FPU and so the
+instruction does not need emulation.  These
+instructions are not generated unless you also use the
+@option{-funsafe-math-optimizations} switch.
+
+@item -malign-double
+@itemx -mno-align-double
+@opindex malign-double
+@opindex mno-align-double
+Control whether GCC aligns @code{double}, @code{long double}, and
+@code{long long} variables on a two-word boundary or a one-word
+boundary.  Aligning @code{double} variables on a two-word boundary
+produces code that runs somewhat faster on a Pentium at the
+expense of more memory.
+
+On x86-64, @option{-malign-double} is enabled by default.
+
+@strong{Warning:} if you use the @option{-malign-double} switch,
+structures containing the above types are aligned differently than
+the published application binary interface specifications for the 386
+and are not binary compatible with structures in code compiled
+without that switch.
+
+@item -m96bit-long-double
+@itemx -m128bit-long-double
+@opindex m96bit-long-double
+@opindex m128bit-long-double
+These switches control the size of @code{long double} type.  The i386
+application binary interface specifies the size to be 96 bits,
+so @option{-m96bit-long-double} is the default in 32-bit mode.
+
+Modern architectures (Pentium and newer) prefer @code{long double}
+to be aligned to an 8- or 16-byte boundary.  In arrays or structures
+conforming to the ABI, this is not possible.  So specifying
+@option{-m128bit-long-double} aligns @code{long double}
+to a 16-byte boundary by padding the @code{long double} with an additional
+32-bit zero.
+
+In the x86-64 compiler, @option{-m128bit-long-double} is the default choice as
+its ABI specifies that @code{long double} is aligned on 16-byte boundary.
+
+Notice that neither of these options enable any extra precision over the x87
+standard of 80 bits for a @code{long double}.
+
+@strong{Warning:} if you override the default value for your target ABI, this
+changes the size of 
+structures and arrays containing @code{long double} variables,
+as well as modifying the function calling convention for functions taking
+@code{long double}.  Hence they are not binary-compatible
+with code compiled without that switch.
+
+@item -mlong-double-64
+@itemx -mlong-double-80
+@opindex mlong-double-64
+@opindex mlong-double-80
+These switches control the size of @code{long double} type. A size
+of 64 bits makes the @code{long double} type equivalent to the @code{double}
+type. This is the default for Bionic C library.
+
+@strong{Warning:} if you override the default value for your target ABI, this
+changes the size of
+structures and arrays containing @code{long double} variables,
+as well as modifying the function calling convention for functions taking
+@code{long double}.  Hence they are not binary-compatible
+with code compiled without that switch.
+
+@item -mlarge-data-threshold=@var{threshold}
+@opindex mlarge-data-threshold
+When @option{-mcmodel=medium} is specified, data objects larger than
+@var{threshold} are placed in the large data section.  This value must be the
+same across all objects linked into the binary, and defaults to 65535.
+
+@item -mrtd
+@opindex mrtd
+Use a different function-calling convention, in which functions that
+take a fixed number of arguments return with the @code{ret @var{num}}
+instruction, which pops their arguments while returning.  This saves one
+instruction in the caller since there is no need to pop the arguments
+there.
+
+You can specify that an individual function is called with this calling
+sequence with the function attribute @samp{stdcall}.  You can also
+override the @option{-mrtd} option by using the function attribute
+@samp{cdecl}.  @xref{Function Attributes}.
+
+@strong{Warning:} this calling convention is incompatible with the one
+normally used on Unix, so you cannot use it if you need to call
+libraries compiled with the Unix compiler.
+
+Also, you must provide function prototypes for all functions that
+take variable numbers of arguments (including @code{printf});
+otherwise incorrect code is generated for calls to those
+functions.
+
+In addition, seriously incorrect code results if you call a
+function with too many arguments.  (Normally, extra arguments are
+harmlessly ignored.)
+
+@item -mregparm=@var{num}
+@opindex mregparm
+Control how many registers are used to pass integer arguments.  By
+default, no registers are used to pass arguments, and at most 3
+registers can be used.  You can control this behavior for a specific
+function by using the function attribute @samp{regparm}.
+@xref{Function Attributes}.
+
+@strong{Warning:} if you use this switch, and
+@var{num} is nonzero, then you must build all modules with the same
+value, including any libraries.  This includes the system libraries and
+startup modules.
+
+@item -msseregparm
+@opindex msseregparm
+Use SSE register passing conventions for float and double arguments
+and return values.  You can control this behavior for a specific
+function by using the function attribute @samp{sseregparm}.
+@xref{Function Attributes}.
+
+@strong{Warning:} if you use this switch then you must build all
+modules with the same value, including any libraries.  This includes
+the system libraries and startup modules.
+
+@item -mvect8-ret-in-mem
+@opindex mvect8-ret-in-mem
+Return 8-byte vectors in memory instead of MMX registers.  This is the
+default on Solaris@tie{}8 and 9 and VxWorks to match the ABI of the Sun
+Studio compilers until version 12.  Later compiler versions (starting
+with Studio 12 Update@tie{}1) follow the ABI used by other x86 targets, which
+is the default on Solaris@tie{}10 and later.  @emph{Only} use this option if
+you need to remain compatible with existing code produced by those
+previous compiler versions or older versions of GCC@.
+
+@item -mpc32
+@itemx -mpc64
+@itemx -mpc80
+@opindex mpc32
+@opindex mpc64
+@opindex mpc80
+
+Set 80387 floating-point precision to 32, 64 or 80 bits.  When @option{-mpc32}
+is specified, the significands of results of floating-point operations are
+rounded to 24 bits (single precision); @option{-mpc64} rounds the
+significands of results of floating-point operations to 53 bits (double
+precision) and @option{-mpc80} rounds the significands of results of
+floating-point operations to 64 bits (extended double precision), which is
+the default.  When this option is used, floating-point operations in higher
+precisions are not available to the programmer without setting the FPU
+control word explicitly.
+
+Setting the rounding of floating-point operations to less than the default
+80 bits can speed some programs by 2% or more.  Note that some mathematical
+libraries assume that extended-precision (80-bit) floating-point operations
+are enabled by default; routines in such libraries could suffer significant
+loss of accuracy, typically through so-called ``catastrophic cancellation'',
+when this option is used to set the precision to less than extended precision.
+
+@item -mstackrealign
+@opindex mstackrealign
+Realign the stack at entry.  On the Intel x86, the @option{-mstackrealign}
+option generates an alternate prologue and epilogue that realigns the
+run-time stack if necessary.  This supports mixing legacy codes that keep
+4-byte stack alignment with modern codes that keep 16-byte stack alignment for
+SSE compatibility.  See also the attribute @code{force_align_arg_pointer},
+applicable to individual functions.
+
+@item -mpreferred-stack-boundary=@var{num}
+@opindex mpreferred-stack-boundary
+Attempt to keep the stack boundary aligned to a 2 raised to @var{num}
+byte boundary.  If @option{-mpreferred-stack-boundary} is not specified,
+the default is 4 (16 bytes or 128 bits).
+
+@strong{Warning:} When generating code for the x86-64 architecture with
+SSE extensions disabled, @option{-mpreferred-stack-boundary=3} can be
+used to keep the stack boundary aligned to 8 byte boundary.  Since
+x86-64 ABI require 16 byte stack alignment, this is ABI incompatible and
+intended to be used in controlled environment where stack space is
+important limitation.  This option will lead to wrong code when functions
+compiled with 16 byte stack alignment (such as functions from a standard
+library) are called with misaligned stack.  In this case, SSE
+instructions may lead to misaligned memory access traps.  In addition,
+variable arguments will be handled incorrectly for 16 byte aligned
+objects (including x87 long double and __int128), leading to wrong
+results.  You must build all modules with
+@option{-mpreferred-stack-boundary=3}, including any libraries.  This
+includes the system libraries and startup modules.
+
+@item -mincoming-stack-boundary=@var{num}
+@opindex mincoming-stack-boundary
+Assume the incoming stack is aligned to a 2 raised to @var{num} byte
+boundary.  If @option{-mincoming-stack-boundary} is not specified,
+the one specified by @option{-mpreferred-stack-boundary} is used.
+
+On Pentium and Pentium Pro, @code{double} and @code{long double} values
+should be aligned to an 8-byte boundary (see @option{-malign-double}) or
+suffer significant run time performance penalties.  On Pentium III, the
+Streaming SIMD Extension (SSE) data type @code{__m128} may not work
+properly if it is not 16-byte aligned.
+
+To ensure proper alignment of this values on the stack, the stack boundary
+must be as aligned as that required by any value stored on the stack.
+Further, every function must be generated such that it keeps the stack
+aligned.  Thus calling a function compiled with a higher preferred
+stack boundary from a function compiled with a lower preferred stack
+boundary most likely misaligns the stack.  It is recommended that
+libraries that use callbacks always use the default setting.
+
+This extra alignment does consume extra stack space, and generally
+increases code size.  Code that is sensitive to stack space usage, such
+as embedded systems and operating system kernels, may want to reduce the
+preferred alignment to @option{-mpreferred-stack-boundary=2}.
+
+@item -mmmx
+@itemx -mno-mmx
+@itemx -msse
+@itemx -mno-sse
+@itemx -msse2
+@itemx -mno-sse2
+@itemx -msse3
+@itemx -mno-sse3
+@itemx -mssse3
+@itemx -mno-ssse3
+@itemx -msse4.1
+@need 800
+@itemx -mno-sse4.1
+@itemx -msse4.2
+@itemx -mno-sse4.2
+@itemx -msse4
+@itemx -mno-sse4
+@itemx -mavx
+@itemx -mno-avx
+@itemx -mavx2
+@itemx -mno-avx2
+@itemx -maes
+@itemx -mno-aes
+@itemx -mpclmul
+@need 800
+@itemx -mno-pclmul
+@itemx -mfsgsbase
+@itemx -mno-fsgsbase
+@itemx -mrdrnd
+@itemx -mno-rdrnd
+@itemx -mf16c
+@itemx -mno-f16c
+@itemx -mfma
+@itemx -mno-fma
+@itemx -msse4a
+@itemx -mno-sse4a
+@itemx -mfma4
+@need 800
+@itemx -mno-fma4
+@itemx -mxop
+@itemx -mno-xop
+@itemx -mlwp
+@itemx -mno-lwp
+@itemx -m3dnow
+@itemx -mno-3dnow
+@itemx -mpopcnt
+@itemx -mno-popcnt
+@itemx -mabm
+@itemx -mno-abm
+@itemx -mbmi
+@itemx -mbmi2
+@itemx -mno-bmi
+@itemx -mno-bmi2
+@itemx -mlzcnt
+@itemx -mno-lzcnt
+@itemx -mrtm
+@itemx -mtbm
+@itemx -mno-tbm
+@opindex mmmx
+@opindex mno-mmx
+@opindex msse
+@opindex mno-sse
+@opindex m3dnow
+@opindex mno-3dnow
+These switches enable or disable the use of instructions in the MMX, SSE,
+SSE2, SSE3, SSSE3, SSE4.1, AVX, AVX2, AES, PCLMUL, FSGSBASE, RDRND, F16C,
+FMA, SSE4A, FMA4, XOP, LWP, ABM, BMI, BMI2, LZCNT, RTM or 3DNow!@:
+extended instruction sets.
+These extensions are also available as built-in functions: see
+@ref{X86 Built-in Functions}, for details of the functions enabled and
+disabled by these switches.
+
+To generate SSE/SSE2 instructions automatically from floating-point
+code (as opposed to 387 instructions), see @option{-mfpmath=sse}.
+
+GCC depresses SSEx instructions when @option{-mavx} is used. Instead, it
+generates new AVX instructions or AVX equivalence for all SSEx instructions
+when needed.
+
+These options enable GCC to use these extended instructions in
+generated code, even without @option{-mfpmath=sse}.  Applications that
+perform run-time CPU detection must compile separate files for each
+supported architecture, using the appropriate flags.  In particular,
+the file containing the CPU detection code should be compiled without
+these options.
+
+@item -mcld
+@opindex mcld
+This option instructs GCC to emit a @code{cld} instruction in the prologue
+of functions that use string instructions.  String instructions depend on
+the DF flag to select between autoincrement or autodecrement mode.  While the
+ABI specifies the DF flag to be cleared on function entry, some operating
+systems violate this specification by not clearing the DF flag in their
+exception dispatchers.  The exception handler can be invoked with the DF flag
+set, which leads to wrong direction mode when string instructions are used.
+This option can be enabled by default on 32-bit x86 targets by configuring
+GCC with the @option{--enable-cld} configure option.  Generation of @code{cld}
+instructions can be suppressed with the @option{-mno-cld} compiler option
+in this case.
+
+@item -mvzeroupper
+@opindex mvzeroupper
+This option instructs GCC to emit a @code{vzeroupper} instruction
+before a transfer of control flow out of the function to minimize
+the AVX to SSE transition penalty as well as remove unnecessary @code{zeroupper}
+intrinsics.
+
+@item -mprefer-avx128
+@opindex mprefer-avx128
+This option instructs GCC to use 128-bit AVX instructions instead of
+256-bit AVX instructions in the auto-vectorizer.
+
+@item -mcx16
+@opindex mcx16
+This option enables GCC to generate @code{CMPXCHG16B} instructions.
+@code{CMPXCHG16B} allows for atomic operations on 128-bit double quadword
+(or oword) data types.  
+This is useful for high-resolution counters that can be updated
+by multiple processors (or cores).  This instruction is generated as part of
+atomic built-in functions: see @ref{__sync Builtins} or
+@ref{__atomic Builtins} for details.
+
+@item -msahf
+@opindex msahf
+This option enables generation of @code{SAHF} instructions in 64-bit code.
+Early Intel Pentium 4 CPUs with Intel 64 support,
+prior to the introduction of Pentium 4 G1 step in December 2005,
+lacked the @code{LAHF} and @code{SAHF} instructions
+which were supported by AMD64.
+These are load and store instructions, respectively, for certain status flags.
+In 64-bit mode, the @code{SAHF} instruction is used to optimize @code{fmod},
+@code{drem}, and @code{remainder} built-in functions;
+see @ref{Other Builtins} for details.
+
+@item -mmovbe
+@opindex mmovbe
+This option enables use of the @code{movbe} instruction to implement
+@code{__builtin_bswap32} and @code{__builtin_bswap64}.
+
+@item -mcrc32
+@opindex mcrc32
+This option enables built-in functions @code{__builtin_ia32_crc32qi},
+@code{__builtin_ia32_crc32hi}, @code{__builtin_ia32_crc32si} and
+@code{__builtin_ia32_crc32di} to generate the @code{crc32} machine instruction.
+
+@item -mrecip
+@opindex mrecip
+This option enables use of @code{RCPSS} and @code{RSQRTSS} instructions
+(and their vectorized variants @code{RCPPS} and @code{RSQRTPS})
+with an additional Newton-Raphson step
+to increase precision instead of @code{DIVSS} and @code{SQRTSS}
+(and their vectorized
+variants) for single-precision floating-point arguments.  These instructions
+are generated only when @option{-funsafe-math-optimizations} is enabled
+together with @option{-finite-math-only} and @option{-fno-trapping-math}.
+Note that while the throughput of the sequence is higher than the throughput
+of the non-reciprocal instruction, the precision of the sequence can be
+decreased by up to 2 ulp (i.e. the inverse of 1.0 equals 0.99999994).
+
+Note that GCC implements @code{1.0f/sqrtf(@var{x})} in terms of @code{RSQRTSS}
+(or @code{RSQRTPS}) already with @option{-ffast-math} (or the above option
+combination), and doesn't need @option{-mrecip}.
+
+Also note that GCC emits the above sequence with additional Newton-Raphson step
+for vectorized single-float division and vectorized @code{sqrtf(@var{x})}
+already with @option{-ffast-math} (or the above option combination), and
+doesn't need @option{-mrecip}.
+
+@item -mrecip=@var{opt}
+@opindex mrecip=opt
+This option controls which reciprocal estimate instructions
+may be used.  @var{opt} is a comma-separated list of options, which may
+be preceded by a @samp{!} to invert the option:
+
+@table @samp
+@item all
+Enable all estimate instructions.
+
+@item default
+Enable the default instructions, equivalent to @option{-mrecip}.
+
+@item none
+Disable all estimate instructions, equivalent to @option{-mno-recip}.
+
+@item div
+Enable the approximation for scalar division.
+
+@item vec-div
+Enable the approximation for vectorized division.
+
+@item sqrt
+Enable the approximation for scalar square root.
+
+@item vec-sqrt
+Enable the approximation for vectorized square root.
+@end table
+
+So, for example, @option{-mrecip=all,!sqrt} enables
+all of the reciprocal approximations, except for square root.
+
+@item -mveclibabi=@var{type}
+@opindex mveclibabi
+Specifies the ABI type to use for vectorizing intrinsics using an
+external library.  Supported values for @var{type} are @samp{svml} 
+for the Intel short
+vector math library and @samp{acml} for the AMD math core library.
+To use this option, both @option{-ftree-vectorize} and
+@option{-funsafe-math-optimizations} have to be enabled, and an SVML or ACML 
+ABI-compatible library must be specified at link time.
+
+GCC currently emits calls to @code{vmldExp2},
+@code{vmldLn2}, @code{vmldLog102}, @code{vmldLog102}, @code{vmldPow2},
+@code{vmldTanh2}, @code{vmldTan2}, @code{vmldAtan2}, @code{vmldAtanh2},
+@code{vmldCbrt2}, @code{vmldSinh2}, @code{vmldSin2}, @code{vmldAsinh2},
+@code{vmldAsin2}, @code{vmldCosh2}, @code{vmldCos2}, @code{vmldAcosh2},
+@code{vmldAcos2}, @code{vmlsExp4}, @code{vmlsLn4}, @code{vmlsLog104},
+@code{vmlsLog104}, @code{vmlsPow4}, @code{vmlsTanh4}, @code{vmlsTan4},
+@code{vmlsAtan4}, @code{vmlsAtanh4}, @code{vmlsCbrt4}, @code{vmlsSinh4},
+@code{vmlsSin4}, @code{vmlsAsinh4}, @code{vmlsAsin4}, @code{vmlsCosh4},
+@code{vmlsCos4}, @code{vmlsAcosh4} and @code{vmlsAcos4} for corresponding
+function type when @option{-mveclibabi=svml} is used, and @code{__vrd2_sin},
+@code{__vrd2_cos}, @code{__vrd2_exp}, @code{__vrd2_log}, @code{__vrd2_log2},
+@code{__vrd2_log10}, @code{__vrs4_sinf}, @code{__vrs4_cosf},
+@code{__vrs4_expf}, @code{__vrs4_logf}, @code{__vrs4_log2f},
+@code{__vrs4_log10f} and @code{__vrs4_powf} for the corresponding function type
+when @option{-mveclibabi=acml} is used.  
+
+@item -mabi=@var{name}
+@opindex mabi
+Generate code for the specified calling convention.  Permissible values
+are @samp{sysv} for the ABI used on GNU/Linux and other systems, and
+@samp{ms} for the Microsoft ABI.  The default is to use the Microsoft
+ABI when targeting Microsoft Windows and the SysV ABI on all other systems.
+You can control this behavior for a specific function by
+using the function attribute @samp{ms_abi}/@samp{sysv_abi}.
+@xref{Function Attributes}.
+
+@item -mtls-dialect=@var{type}
+@opindex mtls-dialect
+Generate code to access thread-local storage using the @samp{gnu} or
+@samp{gnu2} conventions.  @samp{gnu} is the conservative default;
+@samp{gnu2} is more efficient, but it may add compile- and run-time
+requirements that cannot be satisfied on all systems.
+
+@item -mpush-args
+@itemx -mno-push-args
+@opindex mpush-args
+@opindex mno-push-args
+Use PUSH operations to store outgoing parameters.  This method is shorter
+and usually equally fast as method using SUB/MOV operations and is enabled
+by default.  In some cases disabling it may improve performance because of
+improved scheduling and reduced dependencies.
+
+@item -maccumulate-outgoing-args
+@opindex maccumulate-outgoing-args
+If enabled, the maximum amount of space required for outgoing arguments is
+computed in the function prologue.  This is faster on most modern CPUs
+because of reduced dependencies, improved scheduling and reduced stack usage
+when the preferred stack boundary is not equal to 2.  The drawback is a notable
+increase in code size.  This switch implies @option{-mno-push-args}.
+
+@item -mthreads
+@opindex mthreads
+Support thread-safe exception handling on MinGW.  Programs that rely
+on thread-safe exception handling must compile and link all code with the
+@option{-mthreads} option.  When compiling, @option{-mthreads} defines
+@code{-D_MT}; when linking, it links in a special thread helper library
+@option{-lmingwthrd} which cleans up per-thread exception-handling data.
+
+@item -mno-align-stringops
+@opindex mno-align-stringops
+Do not align the destination of inlined string operations.  This switch reduces
+code size and improves performance in case the destination is already aligned,
+but GCC doesn't know about it.
+
+@item -minline-all-stringops
+@opindex minline-all-stringops
+By default GCC inlines string operations only when the destination is 
+known to be aligned to least a 4-byte boundary.  
+This enables more inlining and increases code
+size, but may improve performance of code that depends on fast
+@code{memcpy}, @code{strlen},
+and @code{memset} for short lengths.
+
+@item -minline-stringops-dynamically
+@opindex minline-stringops-dynamically
+For string operations of unknown size, use run-time checks with
+inline code for small blocks and a library call for large blocks.
+
+@item -mstringop-strategy=@var{alg}
+@opindex mstringop-strategy=@var{alg}
+Override the internal decision heuristic for the particular algorithm to use
+for inlining string operations.  The allowed values for @var{alg} are:
+
+@table @samp
+@item rep_byte
+@itemx rep_4byte
+@itemx rep_8byte
+Expand using i386 @code{rep} prefix of the specified size.
+
+@item byte_loop
+@itemx loop
+@itemx unrolled_loop
+Expand into an inline loop.
+
+@item libcall
+Always use a library call.
+@end table
+
+@item -momit-leaf-frame-pointer
+@opindex momit-leaf-frame-pointer
+Don't keep the frame pointer in a register for leaf functions.  This
+avoids the instructions to save, set up, and restore frame pointers and
+makes an extra register available in leaf functions.  The option
+@option{-fomit-leaf-frame-pointer} removes the frame pointer for leaf functions,
+which might make debugging harder.
+
+@item -mtls-direct-seg-refs
+@itemx -mno-tls-direct-seg-refs
+@opindex mtls-direct-seg-refs
+Controls whether TLS variables may be accessed with offsets from the
+TLS segment register (@code{%gs} for 32-bit, @code{%fs} for 64-bit),
+or whether the thread base pointer must be added.  Whether or not this
+is valid depends on the operating system, and whether it maps the
+segment to cover the entire TLS area.
+
+For systems that use the GNU C Library, the default is on.
+
+@item -msse2avx
+@itemx -mno-sse2avx
+@opindex msse2avx
+Specify that the assembler should encode SSE instructions with VEX
+prefix.  The option @option{-mavx} turns this on by default.
+
+@item -mfentry
+@itemx -mno-fentry
+@opindex mfentry
+If profiling is active (@option{-pg}), put the profiling
+counter call before the prologue.
+Note: On x86 architectures the attribute @code{ms_hook_prologue}
+isn't possible at the moment for @option{-mfentry} and @option{-pg}.
+
+@item -m8bit-idiv
+@itemx -mno-8bit-idiv
+@opindex 8bit-idiv
+On some processors, like Intel Atom, 8-bit unsigned integer divide is
+much faster than 32-bit/64-bit integer divide.  This option generates a
+run-time check.  If both dividend and divisor are within range of 0
+to 255, 8-bit unsigned integer divide is used instead of
+32-bit/64-bit integer divide.
+
+@item -mavx256-split-unaligned-load
+@itemx -mavx256-split-unaligned-store
+@opindex avx256-split-unaligned-load
+@opindex avx256-split-unaligned-store
+Split 32-byte AVX unaligned load and store.
+
+@end table
+
+These @samp{-m} switches are supported in addition to the above
+on x86-64 processors in 64-bit environments.
+
+@table @gcctabopt
+@item -m32
+@itemx -m64
+@itemx -mx32
+@opindex m32
+@opindex m64
+@opindex mx32
+Generate code for a 32-bit or 64-bit environment.
+The @option{-m32} option sets @code{int}, @code{long}, and pointer types
+to 32 bits, and
+generates code that runs on any i386 system.
+
+The @option{-m64} option sets @code{int} to 32 bits and @code{long} and pointer
+types to 64 bits, and generates code for the x86-64 architecture.
+For Darwin only the @option{-m64} option also turns off the @option{-fno-pic}
+and @option{-mdynamic-no-pic} options.
+
+The @option{-mx32} option sets @code{int}, @code{long}, and pointer types
+to 32 bits, and
+generates code for the x86-64 architecture.
+
+@item -mno-red-zone
+@opindex mno-red-zone
+Do not use a so-called ``red zone'' for x86-64 code.  The red zone is mandated
+by the x86-64 ABI; it is a 128-byte area beyond the location of the
+stack pointer that is not modified by signal or interrupt handlers
+and therefore can be used for temporary data without adjusting the stack
+pointer.  The flag @option{-mno-red-zone} disables this red zone.
+
+@item -mcmodel=small
+@opindex mcmodel=small
+Generate code for the small code model: the program and its symbols must
+be linked in the lower 2 GB of the address space.  Pointers are 64 bits.
+Programs can be statically or dynamically linked.  This is the default
+code model.
+
+@item -mcmodel=kernel
+@opindex mcmodel=kernel
+Generate code for the kernel code model.  The kernel runs in the
+negative 2 GB of the address space.
+This model has to be used for Linux kernel code.
+
+@item -mcmodel=medium
+@opindex mcmodel=medium
+Generate code for the medium model: the program is linked in the lower 2
+GB of the address space.  Small symbols are also placed there.  Symbols
+with sizes larger than @option{-mlarge-data-threshold} are put into
+large data or BSS sections and can be located above 2GB.  Programs can
+be statically or dynamically linked.
+
+@item -mcmodel=large
+@opindex mcmodel=large
+Generate code for the large model.  This model makes no assumptions
+about addresses and sizes of sections.
+
+@item -maddress-mode=long
+@opindex maddress-mode=long
+Generate code for long address mode.  This is only supported for 64-bit
+and x32 environments.  It is the default address mode for 64-bit
+environments.
+
+@item -maddress-mode=short
+@opindex maddress-mode=short
+Generate code for short address mode.  This is only supported for 32-bit
+and x32 environments.  It is the default address mode for 32-bit and
+x32 environments.
+@end table
+
+@node i386 and x86-64 Windows Options
+@subsection i386 and x86-64 Windows Options
+@cindex i386 and x86-64 Windows Options
+
+These additional options are available for Microsoft Windows targets:
+
+@table @gcctabopt
+@item -mconsole
+@opindex mconsole
+This option
+specifies that a console application is to be generated, by
+instructing the linker to set the PE header subsystem type
+required for console applications.
+This option is available for Cygwin and MinGW targets and is
+enabled by default on those targets.
+
+@item -mdll
+@opindex mdll
+This option is available for Cygwin and MinGW targets.  It
+specifies that a DLL---a dynamic link library---is to be
+generated, enabling the selection of the required runtime
+startup object and entry point.
+
+@item -mnop-fun-dllimport
+@opindex mnop-fun-dllimport
+This option is available for Cygwin and MinGW targets.  It
+specifies that the @code{dllimport} attribute should be ignored.
+
+@item -mthread
+@opindex mthread
+This option is available for MinGW targets. It specifies
+that MinGW-specific thread support is to be used.
+
+@item -municode
+@opindex municode
+This option is available for MinGW-w64 targets.  It causes
+the @code{UNICODE} preprocessor macro to be predefined, and
+chooses Unicode-capable runtime startup code.
+
+@item -mwin32
+@opindex mwin32
+This option is available for Cygwin and MinGW targets.  It
+specifies that the typical Microsoft Windows predefined macros are to
+be set in the pre-processor, but does not influence the choice
+of runtime library/startup code.
+
+@item -mwindows
+@opindex mwindows
+This option is available for Cygwin and MinGW targets.  It
+specifies that a GUI application is to be generated by
+instructing the linker to set the PE header subsystem type
+appropriately.
+
+@item -fno-set-stack-executable
+@opindex fno-set-stack-executable
+This option is available for MinGW targets. It specifies that
+the executable flag for the stack used by nested functions isn't
+set. This is necessary for binaries running in kernel mode of
+Microsoft Windows, as there the User32 API, which is used to set executable
+privileges, isn't available.
+
+@item -fwritable-relocated-rdata
+@opindex fno-writable-relocated-rdata
+This option is available for MinGW and Cygwin targets.  It specifies
+that relocated-data in read-only section is put into .data
+section.  This is a necessary for older runtimes not supporting
+modification of .rdata sections for pseudo-relocation.
+
+@item -mpe-aligned-commons
+@opindex mpe-aligned-commons
+This option is available for Cygwin and MinGW targets.  It
+specifies that the GNU extension to the PE file format that
+permits the correct alignment of COMMON variables should be
+used when generating code.  It is enabled by default if
+GCC detects that the target assembler found during configuration
+supports the feature.
+@end table
+
+See also under @ref{i386 and x86-64 Options} for standard options.
+
+@node IA-64 Options
+@subsection IA-64 Options
+@cindex IA-64 Options
+
+These are the @samp{-m} options defined for the Intel IA-64 architecture.
+
+@table @gcctabopt
+@item -mbig-endian
+@opindex mbig-endian
+Generate code for a big-endian target.  This is the default for HP-UX@.
+
+@item -mlittle-endian
+@opindex mlittle-endian
+Generate code for a little-endian target.  This is the default for AIX5
+and GNU/Linux.
+
+@item -mgnu-as
+@itemx -mno-gnu-as
+@opindex mgnu-as
+@opindex mno-gnu-as
+Generate (or don't) code for the GNU assembler.  This is the default.
+@c Also, this is the default if the configure option @option{--with-gnu-as}
+@c is used.
+
+@item -mgnu-ld
+@itemx -mno-gnu-ld
+@opindex mgnu-ld
+@opindex mno-gnu-ld
+Generate (or don't) code for the GNU linker.  This is the default.
+@c Also, this is the default if the configure option @option{--with-gnu-ld}
+@c is used.
+
+@item -mno-pic
+@opindex mno-pic
+Generate code that does not use a global pointer register.  The result
+is not position independent code, and violates the IA-64 ABI@.
+
+@item -mvolatile-asm-stop
+@itemx -mno-volatile-asm-stop
+@opindex mvolatile-asm-stop
+@opindex mno-volatile-asm-stop
+Generate (or don't) a stop bit immediately before and after volatile asm
+statements.
+
+@item -mregister-names
+@itemx -mno-register-names
+@opindex mregister-names
+@opindex mno-register-names
+Generate (or don't) @samp{in}, @samp{loc}, and @samp{out} register names for
+the stacked registers.  This may make assembler output more readable.
+
+@item -mno-sdata
+@itemx -msdata
+@opindex mno-sdata
+@opindex msdata
+Disable (or enable) optimizations that use the small data section.  This may
+be useful for working around optimizer bugs.
+
+@item -mconstant-gp
+@opindex mconstant-gp
+Generate code that uses a single constant global pointer value.  This is
+useful when compiling kernel code.
+
+@item -mauto-pic
+@opindex mauto-pic
+Generate code that is self-relocatable.  This implies @option{-mconstant-gp}.
+This is useful when compiling firmware code.
+
+@item -minline-float-divide-min-latency
+@opindex minline-float-divide-min-latency
+Generate code for inline divides of floating-point values
+using the minimum latency algorithm.
+
+@item -minline-float-divide-max-throughput
+@opindex minline-float-divide-max-throughput
+Generate code for inline divides of floating-point values
+using the maximum throughput algorithm.
+
+@item -mno-inline-float-divide
+@opindex mno-inline-float-divide
+Do not generate inline code for divides of floating-point values.
+
+@item -minline-int-divide-min-latency
+@opindex minline-int-divide-min-latency
+Generate code for inline divides of integer values
+using the minimum latency algorithm.
+
+@item -minline-int-divide-max-throughput
+@opindex minline-int-divide-max-throughput
+Generate code for inline divides of integer values
+using the maximum throughput algorithm.
+
+@item -mno-inline-int-divide
+@opindex mno-inline-int-divide
+Do not generate inline code for divides of integer values.
+
+@item -minline-sqrt-min-latency
+@opindex minline-sqrt-min-latency
+Generate code for inline square roots
+using the minimum latency algorithm.
+
+@item -minline-sqrt-max-throughput
+@opindex minline-sqrt-max-throughput
+Generate code for inline square roots
+using the maximum throughput algorithm.
+
+@item -mno-inline-sqrt
+@opindex mno-inline-sqrt
+Do not generate inline code for @code{sqrt}.
+
+@item -mfused-madd
+@itemx -mno-fused-madd
+@opindex mfused-madd
+@opindex mno-fused-madd
+Do (don't) generate code that uses the fused multiply/add or multiply/subtract
+instructions.  The default is to use these instructions.
+
+@item -mno-dwarf2-asm
+@itemx -mdwarf2-asm
+@opindex mno-dwarf2-asm
+@opindex mdwarf2-asm
+Don't (or do) generate assembler code for the DWARF 2 line number debugging
+info.  This may be useful when not using the GNU assembler.
+
+@item -mearly-stop-bits
+@itemx -mno-early-stop-bits
+@opindex mearly-stop-bits
+@opindex mno-early-stop-bits
+Allow stop bits to be placed earlier than immediately preceding the
+instruction that triggered the stop bit.  This can improve instruction
+scheduling, but does not always do so.
+
+@item -mfixed-range=@var{register-range}
+@opindex mfixed-range
+Generate code treating the given register range as fixed registers.
+A fixed register is one that the register allocator cannot use.  This is
+useful when compiling kernel code.  A register range is specified as
+two registers separated by a dash.  Multiple register ranges can be
+specified separated by a comma.
+
+@item -mtls-size=@var{tls-size}
+@opindex mtls-size
+Specify bit size of immediate TLS offsets.  Valid values are 14, 22, and
+64.
+
+@item -mtune=@var{cpu-type}
+@opindex mtune
+Tune the instruction scheduling for a particular CPU, Valid values are
+@samp{itanium}, @samp{itanium1}, @samp{merced}, @samp{itanium2},
+and @samp{mckinley}.
+
+@item -milp32
+@itemx -mlp64
+@opindex milp32
+@opindex mlp64
+Generate code for a 32-bit or 64-bit environment.
+The 32-bit environment sets int, long and pointer to 32 bits.
+The 64-bit environment sets int to 32 bits and long and pointer
+to 64 bits.  These are HP-UX specific flags.
+
+@item -mno-sched-br-data-spec
+@itemx -msched-br-data-spec
+@opindex mno-sched-br-data-spec
+@opindex msched-br-data-spec
+(Dis/En)able data speculative scheduling before reload.
+This results in generation of @code{ld.a} instructions and
+the corresponding check instructions (@code{ld.c} / @code{chk.a}).
+The default is 'disable'.
+
+@item -msched-ar-data-spec
+@itemx -mno-sched-ar-data-spec
+@opindex msched-ar-data-spec
+@opindex mno-sched-ar-data-spec
+(En/Dis)able data speculative scheduling after reload.
+This results in generation of @code{ld.a} instructions and
+the corresponding check instructions (@code{ld.c} / @code{chk.a}).
+The default is 'enable'.
+
+@item -mno-sched-control-spec
+@itemx -msched-control-spec
+@opindex mno-sched-control-spec
+@opindex msched-control-spec
+(Dis/En)able control speculative scheduling.  This feature is
+available only during region scheduling (i.e.@: before reload).
+This results in generation of the @code{ld.s} instructions and
+the corresponding check instructions @code{chk.s}.
+The default is 'disable'.
+
+@item -msched-br-in-data-spec
+@itemx -mno-sched-br-in-data-spec
+@opindex msched-br-in-data-spec
+@opindex mno-sched-br-in-data-spec
+(En/Dis)able speculative scheduling of the instructions that
+are dependent on the data speculative loads before reload.
+This is effective only with @option{-msched-br-data-spec} enabled.
+The default is 'enable'.
+
+@item -msched-ar-in-data-spec
+@itemx -mno-sched-ar-in-data-spec
+@opindex msched-ar-in-data-spec
+@opindex mno-sched-ar-in-data-spec
+(En/Dis)able speculative scheduling of the instructions that
+are dependent on the data speculative loads after reload.
+This is effective only with @option{-msched-ar-data-spec} enabled.
+The default is 'enable'.
+
+@item -msched-in-control-spec
+@itemx -mno-sched-in-control-spec
+@opindex msched-in-control-spec
+@opindex mno-sched-in-control-spec
+(En/Dis)able speculative scheduling of the instructions that
+are dependent on the control speculative loads.
+This is effective only with @option{-msched-control-spec} enabled.
+The default is 'enable'.
+
+@item -mno-sched-prefer-non-data-spec-insns
+@itemx -msched-prefer-non-data-spec-insns
+@opindex mno-sched-prefer-non-data-spec-insns
+@opindex msched-prefer-non-data-spec-insns
+If enabled, data-speculative instructions are chosen for schedule
+only if there are no other choices at the moment.  This makes
+the use of the data speculation much more conservative.
+The default is 'disable'.
+
+@item -mno-sched-prefer-non-control-spec-insns
+@itemx -msched-prefer-non-control-spec-insns
+@opindex mno-sched-prefer-non-control-spec-insns
+@opindex msched-prefer-non-control-spec-insns
+If enabled, control-speculative instructions are chosen for schedule
+only if there are no other choices at the moment.  This makes
+the use of the control speculation much more conservative.
+The default is 'disable'.
+
+@item -mno-sched-count-spec-in-critical-path
+@itemx -msched-count-spec-in-critical-path
+@opindex mno-sched-count-spec-in-critical-path
+@opindex msched-count-spec-in-critical-path
+If enabled, speculative dependencies are considered during
+computation of the instructions priorities.  This makes the use of the
+speculation a bit more conservative.
+The default is 'disable'.
+
+@item -msched-spec-ldc
+@opindex msched-spec-ldc
+Use a simple data speculation check.  This option is on by default.
+
+@item -msched-control-spec-ldc
+@opindex msched-spec-ldc
+Use a simple check for control speculation.  This option is on by default.
+
+@item -msched-stop-bits-after-every-cycle
+@opindex msched-stop-bits-after-every-cycle
+Place a stop bit after every cycle when scheduling.  This option is on
+by default.
+
+@item -msched-fp-mem-deps-zero-cost
+@opindex msched-fp-mem-deps-zero-cost
+Assume that floating-point stores and loads are not likely to cause a conflict
+when placed into the same instruction group.  This option is disabled by
+default.
+
+@item -msel-sched-dont-check-control-spec
+@opindex msel-sched-dont-check-control-spec
+Generate checks for control speculation in selective scheduling.
+This flag is disabled by default.
+
+@item -msched-max-memory-insns=@var{max-insns}
+@opindex msched-max-memory-insns
+Limit on the number of memory insns per instruction group, giving lower
+priority to subsequent memory insns attempting to schedule in the same
+instruction group. Frequently useful to prevent cache bank conflicts.
+The default value is 1.
+
+@item -msched-max-memory-insns-hard-limit
+@opindex msched-max-memory-insns-hard-limit
+Makes the limit specified by @option{msched-max-memory-insns} a hard limit,
+disallowing more than that number in an instruction group.
+Otherwise, the limit is ``soft'', meaning that non-memory operations
+are preferred when the limit is reached, but memory operations may still
+be scheduled.
+
+@end table
+
+@node LM32 Options
+@subsection LM32 Options
+@cindex LM32 options
+
+These @option{-m} options are defined for the LatticeMico32 architecture:
+
+@table @gcctabopt
+@item -mbarrel-shift-enabled
+@opindex mbarrel-shift-enabled
+Enable barrel-shift instructions.
+
+@item -mdivide-enabled
+@opindex mdivide-enabled
+Enable divide and modulus instructions.
+
+@item -mmultiply-enabled
+@opindex multiply-enabled
+Enable multiply instructions.
+
+@item -msign-extend-enabled
+@opindex msign-extend-enabled
+Enable sign extend instructions.
+
+@item -muser-enabled
+@opindex muser-enabled
+Enable user-defined instructions.
+
+@end table
+
+@node M32C Options
+@subsection M32C Options
+@cindex M32C options
+
+@table @gcctabopt
+@item -mcpu=@var{name}
+@opindex mcpu=
+Select the CPU for which code is generated.  @var{name} may be one of
+@samp{r8c} for the R8C/Tiny series, @samp{m16c} for the M16C (up to
+/60) series, @samp{m32cm} for the M16C/80 series, or @samp{m32c} for
+the M32C/80 series.
+
+@item -msim
+@opindex msim
+Specifies that the program will be run on the simulator.  This causes
+an alternate runtime library to be linked in which supports, for
+example, file I/O@.  You must not use this option when generating
+programs that will run on real hardware; you must provide your own
+runtime library for whatever I/O functions are needed.
+
+@item -memregs=@var{number}
+@opindex memregs=
+Specifies the number of memory-based pseudo-registers GCC uses
+during code generation.  These pseudo-registers are used like real
+registers, so there is a tradeoff between GCC's ability to fit the
+code into available registers, and the performance penalty of using
+memory instead of registers.  Note that all modules in a program must
+be compiled with the same value for this option.  Because of that, you
+must not use this option with GCC's default runtime libraries.
+
+@end table
+
+@node M32R/D Options
+@subsection M32R/D Options
+@cindex M32R/D options
+
+These @option{-m} options are defined for Renesas M32R/D architectures:
+
+@table @gcctabopt
+@item -m32r2
+@opindex m32r2
+Generate code for the M32R/2@.
+
+@item -m32rx
+@opindex m32rx
+Generate code for the M32R/X@.
+
+@item -m32r
+@opindex m32r
+Generate code for the M32R@.  This is the default.
+
+@item -mmodel=small
+@opindex mmodel=small
+Assume all objects live in the lower 16MB of memory (so that their addresses
+can be loaded with the @code{ld24} instruction), and assume all subroutines
+are reachable with the @code{bl} instruction.
+This is the default.
+
+The addressability of a particular object can be set with the
+@code{model} attribute.
+
+@item -mmodel=medium
+@opindex mmodel=medium
+Assume objects may be anywhere in the 32-bit address space (the compiler
+generates @code{seth/add3} instructions to load their addresses), and
+assume all subroutines are reachable with the @code{bl} instruction.
+
+@item -mmodel=large
+@opindex mmodel=large
+Assume objects may be anywhere in the 32-bit address space (the compiler
+generates @code{seth/add3} instructions to load their addresses), and
+assume subroutines may not be reachable with the @code{bl} instruction
+(the compiler generates the much slower @code{seth/add3/jl}
+instruction sequence).
+
+@item -msdata=none
+@opindex msdata=none
+Disable use of the small data area.  Variables are put into
+one of @samp{.data}, @samp{.bss}, or @samp{.rodata} (unless the
+@code{section} attribute has been specified).
+This is the default.
+
+The small data area consists of sections @samp{.sdata} and @samp{.sbss}.
+Objects may be explicitly put in the small data area with the
+@code{section} attribute using one of these sections.
+
+@item -msdata=sdata
+@opindex msdata=sdata
+Put small global and static data in the small data area, but do not
+generate special code to reference them.
+
+@item -msdata=use
+@opindex msdata=use
+Put small global and static data in the small data area, and generate
+special instructions to reference them.
+
+@item -G @var{num}
+@opindex G
+@cindex smaller data references
+Put global and static objects less than or equal to @var{num} bytes
+into the small data or BSS sections instead of the normal data or BSS
+sections.  The default value of @var{num} is 8.
+The @option{-msdata} option must be set to one of @samp{sdata} or @samp{use}
+for this option to have any effect.
+
+All modules should be compiled with the same @option{-G @var{num}} value.
+Compiling with different values of @var{num} may or may not work; if it
+doesn't the linker gives an error message---incorrect code is not
+generated.
+
+@item -mdebug
+@opindex mdebug
+Makes the M32R-specific code in the compiler display some statistics
+that might help in debugging programs.
+
+@item -malign-loops
+@opindex malign-loops
+Align all loops to a 32-byte boundary.
+
+@item -mno-align-loops
+@opindex mno-align-loops
+Do not enforce a 32-byte alignment for loops.  This is the default.
+
+@item -missue-rate=@var{number}
+@opindex missue-rate=@var{number}
+Issue @var{number} instructions per cycle.  @var{number} can only be 1
+or 2.
+
+@item -mbranch-cost=@var{number}
+@opindex mbranch-cost=@var{number}
+@var{number} can only be 1 or 2.  If it is 1 then branches are
+preferred over conditional code, if it is 2, then the opposite applies.
+
+@item -mflush-trap=@var{number}
+@opindex mflush-trap=@var{number}
+Specifies the trap number to use to flush the cache.  The default is
+12.  Valid numbers are between 0 and 15 inclusive.
+
+@item -mno-flush-trap
+@opindex mno-flush-trap
+Specifies that the cache cannot be flushed by using a trap.
+
+@item -mflush-func=@var{name}
+@opindex mflush-func=@var{name}
+Specifies the name of the operating system function to call to flush
+the cache.  The default is @emph{_flush_cache}, but a function call
+is only used if a trap is not available.
+
+@item -mno-flush-func
+@opindex mno-flush-func
+Indicates that there is no OS function for flushing the cache.
+
+@end table
+
+@node M680x0 Options
+@subsection M680x0 Options
+@cindex M680x0 options
+
+These are the @samp{-m} options defined for M680x0 and ColdFire processors.
+The default settings depend on which architecture was selected when
+the compiler was configured; the defaults for the most common choices
+are given below.
+
+@table @gcctabopt
+@item -march=@var{arch}
+@opindex march
+Generate code for a specific M680x0 or ColdFire instruction set
+architecture.  Permissible values of @var{arch} for M680x0
+architectures are: @samp{68000}, @samp{68010}, @samp{68020},
+@samp{68030}, @samp{68040}, @samp{68060} and @samp{cpu32}.  ColdFire
+architectures are selected according to Freescale's ISA classification
+and the permissible values are: @samp{isaa}, @samp{isaaplus},
+@samp{isab} and @samp{isac}.
+
+GCC defines a macro @samp{__mcf@var{arch}__} whenever it is generating
+code for a ColdFire target.  The @var{arch} in this macro is one of the
+@option{-march} arguments given above.
+
+When used together, @option{-march} and @option{-mtune} select code
+that runs on a family of similar processors but that is optimized
+for a particular microarchitecture.
+
+@item -mcpu=@var{cpu}
+@opindex mcpu
+Generate code for a specific M680x0 or ColdFire processor.
+The M680x0 @var{cpu}s are: @samp{68000}, @samp{68010}, @samp{68020},
+@samp{68030}, @samp{68040}, @samp{68060}, @samp{68302}, @samp{68332}
+and @samp{cpu32}.  The ColdFire @var{cpu}s are given by the table
+below, which also classifies the CPUs into families:
+
+@multitable @columnfractions 0.20 0.80
+@item @strong{Family} @tab @strong{@samp{-mcpu} arguments}
+@item @samp{51} @tab @samp{51} @samp{51ac} @samp{51ag} @samp{51cn} @samp{51em} @samp{51je} @samp{51jf} @samp{51jg} @samp{51jm} @samp{51mm} @samp{51qe} @samp{51qm}
+@item @samp{5206} @tab @samp{5202} @samp{5204} @samp{5206}
+@item @samp{5206e} @tab @samp{5206e}
+@item @samp{5208} @tab @samp{5207} @samp{5208}
+@item @samp{5211a} @tab @samp{5210a} @samp{5211a}
+@item @samp{5213} @tab @samp{5211} @samp{5212} @samp{5213}
+@item @samp{5216} @tab @samp{5214} @samp{5216}
+@item @samp{52235} @tab @samp{52230} @samp{52231} @samp{52232} @samp{52233} @samp{52234} @samp{52235}
+@item @samp{5225} @tab @samp{5224} @samp{5225}
+@item @samp{52259} @tab @samp{52252} @samp{52254} @samp{52255} @samp{52256} @samp{52258} @samp{52259}
+@item @samp{5235} @tab @samp{5232} @samp{5233} @samp{5234} @samp{5235} @samp{523x}
+@item @samp{5249} @tab @samp{5249}
+@item @samp{5250} @tab @samp{5250}
+@item @samp{5271} @tab @samp{5270} @samp{5271}
+@item @samp{5272} @tab @samp{5272}
+@item @samp{5275} @tab @samp{5274} @samp{5275}
+@item @samp{5282} @tab @samp{5280} @samp{5281} @samp{5282} @samp{528x}
+@item @samp{53017} @tab @samp{53011} @samp{53012} @samp{53013} @samp{53014} @samp{53015} @samp{53016} @samp{53017}
+@item @samp{5307} @tab @samp{5307}
+@item @samp{5329} @tab @samp{5327} @samp{5328} @samp{5329} @samp{532x}
+@item @samp{5373} @tab @samp{5372} @samp{5373} @samp{537x}
+@item @samp{5407} @tab @samp{5407}
+@item @samp{5475} @tab @samp{5470} @samp{5471} @samp{5472} @samp{5473} @samp{5474} @samp{5475} @samp{547x} @samp{5480} @samp{5481} @samp{5482} @samp{5483} @samp{5484} @samp{5485}
+@end multitable
+
+@option{-mcpu=@var{cpu}} overrides @option{-march=@var{arch}} if
+@var{arch} is compatible with @var{cpu}.  Other combinations of
+@option{-mcpu} and @option{-march} are rejected.
+
+GCC defines the macro @samp{__mcf_cpu_@var{cpu}} when ColdFire target
+@var{cpu} is selected.  It also defines @samp{__mcf_family_@var{family}},
+where the value of @var{family} is given by the table above.
+
+@item -mtune=@var{tune}
+@opindex mtune
+Tune the code for a particular microarchitecture within the
+constraints set by @option{-march} and @option{-mcpu}.
+The M680x0 microarchitectures are: @samp{68000}, @samp{68010},
+@samp{68020}, @samp{68030}, @samp{68040}, @samp{68060}
+and @samp{cpu32}.  The ColdFire microarchitectures
+are: @samp{cfv1}, @samp{cfv2}, @samp{cfv3}, @samp{cfv4} and @samp{cfv4e}.
+
+You can also use @option{-mtune=68020-40} for code that needs
+to run relatively well on 68020, 68030 and 68040 targets.
+@option{-mtune=68020-60} is similar but includes 68060 targets
+as well.  These two options select the same tuning decisions as
+@option{-m68020-40} and @option{-m68020-60} respectively.
+
+GCC defines the macros @samp{__mc@var{arch}} and @samp{__mc@var{arch}__}
+when tuning for 680x0 architecture @var{arch}.  It also defines
+@samp{mc@var{arch}} unless either @option{-ansi} or a non-GNU @option{-std}
+option is used.  If GCC is tuning for a range of architectures,
+as selected by @option{-mtune=68020-40} or @option{-mtune=68020-60},
+it defines the macros for every architecture in the range.
+
+GCC also defines the macro @samp{__m@var{uarch}__} when tuning for
+ColdFire microarchitecture @var{uarch}, where @var{uarch} is one
+of the arguments given above.
+
+@item -m68000
+@itemx -mc68000
+@opindex m68000
+@opindex mc68000
+Generate output for a 68000.  This is the default
+when the compiler is configured for 68000-based systems.
+It is equivalent to @option{-march=68000}.
+
+Use this option for microcontrollers with a 68000 or EC000 core,
+including the 68008, 68302, 68306, 68307, 68322, 68328 and 68356.
+
+@item -m68010
+@opindex m68010
+Generate output for a 68010.  This is the default
+when the compiler is configured for 68010-based systems.
+It is equivalent to @option{-march=68010}.
+
+@item -m68020
+@itemx -mc68020
+@opindex m68020
+@opindex mc68020
+Generate output for a 68020.  This is the default
+when the compiler is configured for 68020-based systems.
+It is equivalent to @option{-march=68020}.
+
+@item -m68030
+@opindex m68030
+Generate output for a 68030.  This is the default when the compiler is
+configured for 68030-based systems.  It is equivalent to
+@option{-march=68030}.
+
+@item -m68040
+@opindex m68040
+Generate output for a 68040.  This is the default when the compiler is
+configured for 68040-based systems.  It is equivalent to
+@option{-march=68040}.
+
+This option inhibits the use of 68881/68882 instructions that have to be
+emulated by software on the 68040.  Use this option if your 68040 does not
+have code to emulate those instructions.
+
+@item -m68060
+@opindex m68060
+Generate output for a 68060.  This is the default when the compiler is
+configured for 68060-based systems.  It is equivalent to
+@option{-march=68060}.
+
+This option inhibits the use of 68020 and 68881/68882 instructions that
+have to be emulated by software on the 68060.  Use this option if your 68060
+does not have code to emulate those instructions.
+
+@item -mcpu32
+@opindex mcpu32
+Generate output for a CPU32.  This is the default
+when the compiler is configured for CPU32-based systems.
+It is equivalent to @option{-march=cpu32}.
+
+Use this option for microcontrollers with a
+CPU32 or CPU32+ core, including the 68330, 68331, 68332, 68333, 68334,
+68336, 68340, 68341, 68349 and 68360.
+
+@item -m5200
+@opindex m5200
+Generate output for a 520X ColdFire CPU@.  This is the default
+when the compiler is configured for 520X-based systems.
+It is equivalent to @option{-mcpu=5206}, and is now deprecated
+in favor of that option.
+
+Use this option for microcontroller with a 5200 core, including
+the MCF5202, MCF5203, MCF5204 and MCF5206.
+
+@item -m5206e
+@opindex m5206e
+Generate output for a 5206e ColdFire CPU@.  The option is now
+deprecated in favor of the equivalent @option{-mcpu=5206e}.
+
+@item -m528x
+@opindex m528x
+Generate output for a member of the ColdFire 528X family.
+The option is now deprecated in favor of the equivalent
+@option{-mcpu=528x}.
+
+@item -m5307
+@opindex m5307
+Generate output for a ColdFire 5307 CPU@.  The option is now deprecated
+in favor of the equivalent @option{-mcpu=5307}.
+
+@item -m5407
+@opindex m5407
+Generate output for a ColdFire 5407 CPU@.  The option is now deprecated
+in favor of the equivalent @option{-mcpu=5407}.
+
+@item -mcfv4e
+@opindex mcfv4e
+Generate output for a ColdFire V4e family CPU (e.g.@: 547x/548x).
+This includes use of hardware floating-point instructions.
+The option is equivalent to @option{-mcpu=547x}, and is now
+deprecated in favor of that option.
+
+@item -m68020-40
+@opindex m68020-40
+Generate output for a 68040, without using any of the new instructions.
+This results in code that can run relatively efficiently on either a
+68020/68881 or a 68030 or a 68040.  The generated code does use the
+68881 instructions that are emulated on the 68040.
+
+The option is equivalent to @option{-march=68020} @option{-mtune=68020-40}.
+
+@item -m68020-60
+@opindex m68020-60
+Generate output for a 68060, without using any of the new instructions.
+This results in code that can run relatively efficiently on either a
+68020/68881 or a 68030 or a 68040.  The generated code does use the
+68881 instructions that are emulated on the 68060.
+
+The option is equivalent to @option{-march=68020} @option{-mtune=68020-60}.
+
+@item -mhard-float
+@itemx -m68881
+@opindex mhard-float
+@opindex m68881
+Generate floating-point instructions.  This is the default for 68020
+and above, and for ColdFire devices that have an FPU@.  It defines the
+macro @samp{__HAVE_68881__} on M680x0 targets and @samp{__mcffpu__}
+on ColdFire targets.
+
+@item -msoft-float
+@opindex msoft-float
+Do not generate floating-point instructions; use library calls instead.
+This is the default for 68000, 68010, and 68832 targets.  It is also
+the default for ColdFire devices that have no FPU.
+
+@item -mdiv
+@itemx -mno-div
+@opindex mdiv
+@opindex mno-div
+Generate (do not generate) ColdFire hardware divide and remainder
+instructions.  If @option{-march} is used without @option{-mcpu},
+the default is ``on'' for ColdFire architectures and ``off'' for M680x0
+architectures.  Otherwise, the default is taken from the target CPU
+(either the default CPU, or the one specified by @option{-mcpu}).  For
+example, the default is ``off'' for @option{-mcpu=5206} and ``on'' for
+@option{-mcpu=5206e}.
+
+GCC defines the macro @samp{__mcfhwdiv__} when this option is enabled.
+
+@item -mshort
+@opindex mshort
+Consider type @code{int} to be 16 bits wide, like @code{short int}.
+Additionally, parameters passed on the stack are also aligned to a
+16-bit boundary even on targets whose API mandates promotion to 32-bit.
+
+@item -mno-short
+@opindex mno-short
+Do not consider type @code{int} to be 16 bits wide.  This is the default.
+
+@item -mnobitfield
+@itemx -mno-bitfield
+@opindex mnobitfield
+@opindex mno-bitfield
+Do not use the bit-field instructions.  The @option{-m68000}, @option{-mcpu32}
+and @option{-m5200} options imply @w{@option{-mnobitfield}}.
+
+@item -mbitfield
+@opindex mbitfield
+Do use the bit-field instructions.  The @option{-m68020} option implies
+@option{-mbitfield}.  This is the default if you use a configuration
+designed for a 68020.
+
+@item -mrtd
+@opindex mrtd
+Use a different function-calling convention, in which functions
+that take a fixed number of arguments return with the @code{rtd}
+instruction, which pops their arguments while returning.  This
+saves one instruction in the caller since there is no need to pop
+the arguments there.
+
+This calling convention is incompatible with the one normally
+used on Unix, so you cannot use it if you need to call libraries
+compiled with the Unix compiler.
+
+Also, you must provide function prototypes for all functions that
+take variable numbers of arguments (including @code{printf});
+otherwise incorrect code is generated for calls to those
+functions.
+
+In addition, seriously incorrect code results if you call a
+function with too many arguments.  (Normally, extra arguments are
+harmlessly ignored.)
+
+The @code{rtd} instruction is supported by the 68010, 68020, 68030,
+68040, 68060 and CPU32 processors, but not by the 68000 or 5200.
+
+@item -mno-rtd
+@opindex mno-rtd
+Do not use the calling conventions selected by @option{-mrtd}.
+This is the default.
+
+@item -malign-int
+@itemx -mno-align-int
+@opindex malign-int
+@opindex mno-align-int
+Control whether GCC aligns @code{int}, @code{long}, @code{long long},
+@code{float}, @code{double}, and @code{long double} variables on a 32-bit
+boundary (@option{-malign-int}) or a 16-bit boundary (@option{-mno-align-int}).
+Aligning variables on 32-bit boundaries produces code that runs somewhat
+faster on processors with 32-bit busses at the expense of more memory.
+
+@strong{Warning:} if you use the @option{-malign-int} switch, GCC
+aligns structures containing the above types differently than
+most published application binary interface specifications for the m68k.
+
+@item -mpcrel
+@opindex mpcrel
+Use the pc-relative addressing mode of the 68000 directly, instead of
+using a global offset table.  At present, this option implies @option{-fpic},
+allowing at most a 16-bit offset for pc-relative addressing.  @option{-fPIC} is
+not presently supported with @option{-mpcrel}, though this could be supported for
+68020 and higher processors.
+
+@item -mno-strict-align
+@itemx -mstrict-align
+@opindex mno-strict-align
+@opindex mstrict-align
+Do not (do) assume that unaligned memory references are handled by
+the system.
+
+@item -msep-data
+Generate code that allows the data segment to be located in a different
+area of memory from the text segment.  This allows for execute-in-place in
+an environment without virtual memory management.  This option implies
+@option{-fPIC}.
+
+@item -mno-sep-data
+Generate code that assumes that the data segment follows the text segment.
+This is the default.
+
+@item -mid-shared-library
+Generate code that supports shared libraries via the library ID method.
+This allows for execute-in-place and shared libraries in an environment
+without virtual memory management.  This option implies @option{-fPIC}.
+
+@item -mno-id-shared-library
+Generate code that doesn't assume ID-based shared libraries are being used.
+This is the default.
+
+@item -mshared-library-id=n
+Specifies the identification number of the ID-based shared library being
+compiled.  Specifying a value of 0 generates more compact code; specifying
+other values forces the allocation of that number to the current
+library, but is no more space- or time-efficient than omitting this option.
+
+@item -mxgot
+@itemx -mno-xgot
+@opindex mxgot
+@opindex mno-xgot
+When generating position-independent code for ColdFire, generate code
+that works if the GOT has more than 8192 entries.  This code is
+larger and slower than code generated without this option.  On M680x0
+processors, this option is not needed; @option{-fPIC} suffices.
+
+GCC normally uses a single instruction to load values from the GOT@.
+While this is relatively efficient, it only works if the GOT
+is smaller than about 64k.  Anything larger causes the linker
+to report an error such as:
+
+@cindex relocation truncated to fit (ColdFire)
+@smallexample
+relocation truncated to fit: R_68K_GOT16O foobar
+@end smallexample
+
+If this happens, you should recompile your code with @option{-mxgot}.
+It should then work with very large GOTs.  However, code generated with
+@option{-mxgot} is less efficient, since it takes 4 instructions to fetch
+the value of a global symbol.
+
+Note that some linkers, including newer versions of the GNU linker,
+can create multiple GOTs and sort GOT entries.  If you have such a linker,
+you should only need to use @option{-mxgot} when compiling a single
+object file that accesses more than 8192 GOT entries.  Very few do.
+
+These options have no effect unless GCC is generating
+position-independent code.
+
+@end table
+
+@node MCore Options
+@subsection MCore Options
+@cindex MCore options
+
+These are the @samp{-m} options defined for the Motorola M*Core
+processors.
+
+@table @gcctabopt
+
+@item -mhardlit
+@itemx -mno-hardlit
+@opindex mhardlit
+@opindex mno-hardlit
+Inline constants into the code stream if it can be done in two
+instructions or less.
+
+@item -mdiv
+@itemx -mno-div
+@opindex mdiv
+@opindex mno-div
+Use the divide instruction.  (Enabled by default).
+
+@item -mrelax-immediate
+@itemx -mno-relax-immediate
+@opindex mrelax-immediate
+@opindex mno-relax-immediate
+Allow arbitrary-sized immediates in bit operations.
+
+@item -mwide-bitfields
+@itemx -mno-wide-bitfields
+@opindex mwide-bitfields
+@opindex mno-wide-bitfields
+Always treat bit-fields as @code{int}-sized.
+
+@item -m4byte-functions
+@itemx -mno-4byte-functions
+@opindex m4byte-functions
+@opindex mno-4byte-functions
+Force all functions to be aligned to a 4-byte boundary.
+
+@item -mcallgraph-data
+@itemx -mno-callgraph-data
+@opindex mcallgraph-data
+@opindex mno-callgraph-data
+Emit callgraph information.
+
+@item -mslow-bytes
+@itemx -mno-slow-bytes
+@opindex mslow-bytes
+@opindex mno-slow-bytes
+Prefer word access when reading byte quantities.
+
+@item -mlittle-endian
+@itemx -mbig-endian
+@opindex mlittle-endian
+@opindex mbig-endian
+Generate code for a little-endian target.
+
+@item -m210
+@itemx -m340
+@opindex m210
+@opindex m340
+Generate code for the 210 processor.
+
+@item -mno-lsim
+@opindex mno-lsim
+Assume that runtime support has been provided and so omit the
+simulator library (@file{libsim.a)} from the linker command line.
+
+@item -mstack-increment=@var{size}
+@opindex mstack-increment
+Set the maximum amount for a single stack increment operation.  Large
+values can increase the speed of programs that contain functions
+that need a large amount of stack space, but they can also trigger a
+segmentation fault if the stack is extended too much.  The default
+value is 0x1000.
+
+@end table
+
+@node MeP Options
+@subsection MeP Options
+@cindex MeP options
+
+@table @gcctabopt
+
+@item -mabsdiff
+@opindex mabsdiff
+Enables the @code{abs} instruction, which is the absolute difference
+between two registers.
+
+@item -mall-opts
+@opindex mall-opts
+Enables all the optional instructions---average, multiply, divide, bit
+operations, leading zero, absolute difference, min/max, clip, and
+saturation.
+
+
+@item -maverage
+@opindex maverage
+Enables the @code{ave} instruction, which computes the average of two
+registers.
+
+@item -mbased=@var{n}
+@opindex mbased=
+Variables of size @var{n} bytes or smaller are placed in the
+@code{.based} section by default.  Based variables use the @code{$tp}
+register as a base register, and there is a 128-byte limit to the
+@code{.based} section.
+
+@item -mbitops
+@opindex mbitops
+Enables the bit operation instructions---bit test (@code{btstm}), set
+(@code{bsetm}), clear (@code{bclrm}), invert (@code{bnotm}), and
+test-and-set (@code{tas}).
+
+@item -mc=@var{name}
+@opindex mc=
+Selects which section constant data is placed in.  @var{name} may
+be @code{tiny}, @code{near}, or @code{far}.
+
+@item -mclip
+@opindex mclip
+Enables the @code{clip} instruction.  Note that @code{-mclip} is not
+useful unless you also provide @code{-mminmax}.
+
+@item -mconfig=@var{name}
+@opindex mconfig=
+Selects one of the built-in core configurations.  Each MeP chip has
+one or more modules in it; each module has a core CPU and a variety of
+coprocessors, optional instructions, and peripherals.  The
+@code{MeP-Integrator} tool, not part of GCC, provides these
+configurations through this option; using this option is the same as
+using all the corresponding command-line options.  The default
+configuration is @code{default}.
+
+@item -mcop
+@opindex mcop
+Enables the coprocessor instructions.  By default, this is a 32-bit
+coprocessor.  Note that the coprocessor is normally enabled via the
+@code{-mconfig=} option.
+
+@item -mcop32
+@opindex mcop32
+Enables the 32-bit coprocessor's instructions.
+
+@item -mcop64
+@opindex mcop64
+Enables the 64-bit coprocessor's instructions.
+
+@item -mivc2
+@opindex mivc2
+Enables IVC2 scheduling.  IVC2 is a 64-bit VLIW coprocessor.
+
+@item -mdc
+@opindex mdc
+Causes constant variables to be placed in the @code{.near} section.
+
+@item -mdiv
+@opindex mdiv
+Enables the @code{div} and @code{divu} instructions.
+
+@item -meb
+@opindex meb
+Generate big-endian code.
+
+@item -mel
+@opindex mel
+Generate little-endian code.
+
+@item -mio-volatile
+@opindex mio-volatile
+Tells the compiler that any variable marked with the @code{io}
+attribute is to be considered volatile.
+
+@item -ml
+@opindex ml
+Causes variables to be assigned to the @code{.far} section by default.
+
+@item -mleadz
+@opindex mleadz
+Enables the @code{leadz} (leading zero) instruction.
+
+@item -mm
+@opindex mm
+Causes variables to be assigned to the @code{.near} section by default.
+
+@item -mminmax
+@opindex mminmax
+Enables the @code{min} and @code{max} instructions.
+
+@item -mmult
+@opindex mmult
+Enables the multiplication and multiply-accumulate instructions.
+
+@item -mno-opts
+@opindex mno-opts
+Disables all the optional instructions enabled by @code{-mall-opts}.
+
+@item -mrepeat
+@opindex mrepeat
+Enables the @code{repeat} and @code{erepeat} instructions, used for
+low-overhead looping.
+
+@item -ms
+@opindex ms
+Causes all variables to default to the @code{.tiny} section.  Note
+that there is a 65536-byte limit to this section.  Accesses to these
+variables use the @code{%gp} base register.
+
+@item -msatur
+@opindex msatur
+Enables the saturation instructions.  Note that the compiler does not
+currently generate these itself, but this option is included for
+compatibility with other tools, like @code{as}.
+
+@item -msdram
+@opindex msdram
+Link the SDRAM-based runtime instead of the default ROM-based runtime.
+
+@item -msim
+@opindex msim
+Link the simulator runtime libraries.
+
+@item -msimnovec
+@opindex msimnovec
+Link the simulator runtime libraries, excluding built-in support
+for reset and exception vectors and tables.
+
+@item -mtf
+@opindex mtf
+Causes all functions to default to the @code{.far} section.  Without
+this option, functions default to the @code{.near} section.
+
+@item -mtiny=@var{n}
+@opindex mtiny=
+Variables that are @var{n} bytes or smaller are allocated to the
+@code{.tiny} section.  These variables use the @code{$gp} base
+register.  The default for this option is 4, but note that there's a
+65536-byte limit to the @code{.tiny} section.
+
+@end table
+
+@node MicroBlaze Options
+@subsection MicroBlaze Options
+@cindex MicroBlaze Options
+
+@table @gcctabopt
+
+@item -msoft-float
+@opindex msoft-float
+Use software emulation for floating point (default).
+
+@item -mhard-float
+@opindex mhard-float
+Use hardware floating-point instructions.
+
+@item -mmemcpy
+@opindex mmemcpy
+Do not optimize block moves, use @code{memcpy}.
+
+@item -mno-clearbss
+@opindex mno-clearbss
+This option is deprecated.  Use @option{-fno-zero-initialized-in-bss} instead.
+
+@item -mcpu=@var{cpu-type}
+@opindex mcpu=
+Use features of, and schedule code for, the given CPU.
+Supported values are in the format @samp{v@var{X}.@var{YY}.@var{Z}},
+where @var{X} is a major version, @var{YY} is the minor version, and
+@var{Z} is compatibility code.  Example values are @samp{v3.00.a},
+@samp{v4.00.b}, @samp{v5.00.a}, @samp{v5.00.b}, @samp{v5.00.b}, @samp{v6.00.a}.
+
+@item -mxl-soft-mul
+@opindex mxl-soft-mul
+Use software multiply emulation (default).
+
+@item -mxl-soft-div
+@opindex mxl-soft-div
+Use software emulation for divides (default).
+
+@item -mxl-barrel-shift
+@opindex mxl-barrel-shift
+Use the hardware barrel shifter.
+
+@item -mxl-pattern-compare
+@opindex mxl-pattern-compare
+Use pattern compare instructions.
+
+@item -msmall-divides
+@opindex msmall-divides
+Use table lookup optimization for small signed integer divisions.
+
+@item -mxl-stack-check
+@opindex mxl-stack-check
+This option is deprecated.  Use @option{-fstack-check} instead.
+
+@item -mxl-gp-opt
+@opindex mxl-gp-opt
+Use GP-relative @code{.sdata}/@code{.sbss} sections.
+
+@item -mxl-multiply-high
+@opindex mxl-multiply-high
+Use multiply high instructions for high part of 32x32 multiply.
+
+@item -mxl-float-convert
+@opindex mxl-float-convert
+Use hardware floating-point conversion instructions.
+
+@item -mxl-float-sqrt
+@opindex mxl-float-sqrt
+Use hardware floating-point square root instruction.
+
+@item -mbig-endian
+@opindex mbig-endian
+Generate code for a big-endian target.
+
+@item -mlittle-endian
+@opindex mlittle-endian
+Generate code for a little-endian target.
+
+@item -mxl-reorder
+@opindex mxl-reorder
+Use reorder instructions (swap and byte reversed load/store).
+
+@item -mxl-mode-@var{app-model}
+Select application model @var{app-model}.  Valid models are
+@table @samp
+@item executable
+normal executable (default), uses startup code @file{crt0.o}.
+
+@item xmdstub
+for use with Xilinx Microprocessor Debugger (XMD) based
+software intrusive debug agent called xmdstub. This uses startup file
+@file{crt1.o} and sets the start address of the program to 0x800.
+
+@item bootstrap
+for applications that are loaded using a bootloader.
+This model uses startup file @file{crt2.o} which does not contain a processor
+reset vector handler. This is suitable for transferring control on a
+processor reset to the bootloader rather than the application.
+
+@item novectors
+for applications that do not require any of the
+MicroBlaze vectors. This option may be useful for applications running
+within a monitoring application. This model uses @file{crt3.o} as a startup file.
+@end table
+
+Option @option{-xl-mode-@var{app-model}} is a deprecated alias for
+@option{-mxl-mode-@var{app-model}}.
+
+@end table
+
+@node MIPS Options
+@subsection MIPS Options
+@cindex MIPS options
+
+@table @gcctabopt
+
+@item -EB
+@opindex EB
+Generate big-endian code.
+
+@item -EL
+@opindex EL
+Generate little-endian code.  This is the default for @samp{mips*el-*-*}
+configurations.
+
+@item -march=@var{arch}
+@opindex march
+Generate code that runs on @var{arch}, which can be the name of a
+generic MIPS ISA, or the name of a particular processor.
+The ISA names are:
+@samp{mips1}, @samp{mips2}, @samp{mips3}, @samp{mips4},
+@samp{mips32}, @samp{mips32r2}, @samp{mips64} and @samp{mips64r2}.
+The processor names are:
+@samp{4kc}, @samp{4km}, @samp{4kp}, @samp{4ksc},
+@samp{4kec}, @samp{4kem}, @samp{4kep}, @samp{4ksd},
+@samp{5kc}, @samp{5kf},
+@samp{20kc},
+@samp{24kc}, @samp{24kf2_1}, @samp{24kf1_1},
+@samp{24kec}, @samp{24kef2_1}, @samp{24kef1_1},
+@samp{34kc}, @samp{34kf2_1}, @samp{34kf1_1}, @samp{34kn},
+@samp{74kc}, @samp{74kf2_1}, @samp{74kf1_1}, @samp{74kf3_2},
+@samp{1004kc}, @samp{1004kf2_1}, @samp{1004kf1_1},
+@samp{loongson2e}, @samp{loongson2f}, @samp{loongson3a},
+@samp{m4k},
+@samp{octeon}, @samp{octeon+}, @samp{octeon2},
+@samp{orion},
+@samp{r2000}, @samp{r3000}, @samp{r3900}, @samp{r4000}, @samp{r4400},
+@samp{r4600}, @samp{r4650}, @samp{r4700}, @samp{r6000}, @samp{r8000},
+@samp{rm7000}, @samp{rm9000},
+@samp{r10000}, @samp{r12000}, @samp{r14000}, @samp{r16000},
+@samp{sb1},
+@samp{sr71000},
+@samp{vr4100}, @samp{vr4111}, @samp{vr4120}, @samp{vr4130}, @samp{vr4300},
+@samp{vr5000}, @samp{vr5400}, @samp{vr5500},
+@samp{xlr} and @samp{xlp}.
+The special value @samp{from-abi} selects the
+most compatible architecture for the selected ABI (that is,
+@samp{mips1} for 32-bit ABIs and @samp{mips3} for 64-bit ABIs)@.
+
+The native Linux/GNU toolchain also supports the value @samp{native},
+which selects the best architecture option for the host processor.
+@option{-march=native} has no effect if GCC does not recognize
+the processor.
+
+In processor names, a final @samp{000} can be abbreviated as @samp{k}
+(for example, @option{-march=r2k}).  Prefixes are optional, and
+@samp{vr} may be written @samp{r}.
+
+Names of the form @samp{@var{n}f2_1} refer to processors with
+FPUs clocked at half the rate of the core, names of the form
+@samp{@var{n}f1_1} refer to processors with FPUs clocked at the same
+rate as the core, and names of the form @samp{@var{n}f3_2} refer to
+processors with FPUs clocked a ratio of 3:2 with respect to the core.
+For compatibility reasons, @samp{@var{n}f} is accepted as a synonym
+for @samp{@var{n}f2_1} while @samp{@var{n}x} and @samp{@var{b}fx} are
+accepted as synonyms for @samp{@var{n}f1_1}.
+
+GCC defines two macros based on the value of this option.  The first
+is @samp{_MIPS_ARCH}, which gives the name of target architecture, as
+a string.  The second has the form @samp{_MIPS_ARCH_@var{foo}},
+where @var{foo} is the capitalized value of @samp{_MIPS_ARCH}@.
+For example, @option{-march=r2000} sets @samp{_MIPS_ARCH}
+to @samp{"r2000"} and defines the macro @samp{_MIPS_ARCH_R2000}.
+
+Note that the @samp{_MIPS_ARCH} macro uses the processor names given
+above.  In other words, it has the full prefix and does not
+abbreviate @samp{000} as @samp{k}.  In the case of @samp{from-abi},
+the macro names the resolved architecture (either @samp{"mips1"} or
+@samp{"mips3"}).  It names the default architecture when no
+@option{-march} option is given.
+
+@item -mtune=@var{arch}
+@opindex mtune
+Optimize for @var{arch}.  Among other things, this option controls
+the way instructions are scheduled, and the perceived cost of arithmetic
+operations.  The list of @var{arch} values is the same as for
+@option{-march}.
+
+When this option is not used, GCC optimizes for the processor
+specified by @option{-march}.  By using @option{-march} and
+@option{-mtune} together, it is possible to generate code that
+runs on a family of processors, but optimize the code for one
+particular member of that family.
+
+@option{-mtune} defines the macros @samp{_MIPS_TUNE} and
+@samp{_MIPS_TUNE_@var{foo}}, which work in the same way as the
+@option{-march} ones described above.
+
+@item -mips1
+@opindex mips1
+Equivalent to @option{-march=mips1}.
+
+@item -mips2
+@opindex mips2
+Equivalent to @option{-march=mips2}.
+
+@item -mips3
+@opindex mips3
+Equivalent to @option{-march=mips3}.
+
+@item -mips4
+@opindex mips4
+Equivalent to @option{-march=mips4}.
+
+@item -mips32
+@opindex mips32
+Equivalent to @option{-march=mips32}.
+
+@item -mips32r2
+@opindex mips32r2
+Equivalent to @option{-march=mips32r2}.
+
+@item -mips64
+@opindex mips64
+Equivalent to @option{-march=mips64}.
+
+@item -mips64r2
+@opindex mips64r2
+Equivalent to @option{-march=mips64r2}.
+
+@item -mips16
+@itemx -mno-mips16
+@opindex mips16
+@opindex mno-mips16
+Generate (do not generate) MIPS16 code.  If GCC is targeting a
+MIPS32 or MIPS64 architecture, it makes use of the MIPS16e ASE@.
+
+MIPS16 code generation can also be controlled on a per-function basis
+by means of @code{mips16} and @code{nomips16} attributes.
+@xref{Function Attributes}, for more information.
+
+@item -mflip-mips16
+@opindex mflip-mips16
+Generate MIPS16 code on alternating functions.  This option is provided
+for regression testing of mixed MIPS16/non-MIPS16 code generation, and is
+not intended for ordinary use in compiling user code.
+
+@item -minterlink-mips16
+@itemx -mno-interlink-mips16
+@opindex minterlink-mips16
+@opindex mno-interlink-mips16
+Require (do not require) that non-MIPS16 code be link-compatible with
+MIPS16 code.
+
+For example, non-MIPS16 code cannot jump directly to MIPS16 code;
+it must either use a call or an indirect jump.  @option{-minterlink-mips16}
+therefore disables direct jumps unless GCC knows that the target of the
+jump is not MIPS16.
+
+@item -mabi=32
+@itemx -mabi=o64
+@itemx -mabi=n32
+@itemx -mabi=64
+@itemx -mabi=eabi
+@opindex mabi=32
+@opindex mabi=o64
+@opindex mabi=n32
+@opindex mabi=64
+@opindex mabi=eabi
+Generate code for the given ABI@.
+
+Note that the EABI has a 32-bit and a 64-bit variant.  GCC normally
+generates 64-bit code when you select a 64-bit architecture, but you
+can use @option{-mgp32} to get 32-bit code instead.
+
+For information about the O64 ABI, see
+@uref{http://gcc.gnu.org/@/projects/@/mipso64-abi.html}.
+
+GCC supports a variant of the o32 ABI in which floating-point registers
+are 64 rather than 32 bits wide.  You can select this combination with
+@option{-mabi=32} @option{-mfp64}.  This ABI relies on the @code{mthc1}
+and @code{mfhc1} instructions and is therefore only supported for
+MIPS32R2 processors.
+
+The register assignments for arguments and return values remain the
+same, but each scalar value is passed in a single 64-bit register
+rather than a pair of 32-bit registers.  For example, scalar
+floating-point values are returned in @samp{$f0} only, not a
+@samp{$f0}/@samp{$f1} pair.  The set of call-saved registers also
+remains the same, but all 64 bits are saved.
+
+@item -mabicalls
+@itemx -mno-abicalls
+@opindex mabicalls
+@opindex mno-abicalls
+Generate (do not generate) code that is suitable for SVR4-style
+dynamic objects.  @option{-mabicalls} is the default for SVR4-based
+systems.
+
+@item -mshared
+@itemx -mno-shared
+Generate (do not generate) code that is fully position-independent,
+and that can therefore be linked into shared libraries.  This option
+only affects @option{-mabicalls}.
+
+All @option{-mabicalls} code has traditionally been position-independent,
+regardless of options like @option{-fPIC} and @option{-fpic}.  However,
+as an extension, the GNU toolchain allows executables to use absolute
+accesses for locally-binding symbols.  It can also use shorter GP
+initialization sequences and generate direct calls to locally-defined
+functions.  This mode is selected by @option{-mno-shared}.
+
+@option{-mno-shared} depends on binutils 2.16 or higher and generates
+objects that can only be linked by the GNU linker.  However, the option
+does not affect the ABI of the final executable; it only affects the ABI
+of relocatable objects.  Using @option{-mno-shared} generally makes
+executables both smaller and quicker.
+
+@option{-mshared} is the default.
+
+@item -mplt
+@itemx -mno-plt
+@opindex mplt
+@opindex mno-plt
+Assume (do not assume) that the static and dynamic linkers
+support PLTs and copy relocations.  This option only affects
+@option{-mno-shared -mabicalls}.  For the n64 ABI, this option
+has no effect without @option{-msym32}.
+
+You can make @option{-mplt} the default by configuring
+GCC with @option{--with-mips-plt}.  The default is
+@option{-mno-plt} otherwise.
+
+@item -mxgot
+@itemx -mno-xgot
+@opindex mxgot
+@opindex mno-xgot
+Lift (do not lift) the usual restrictions on the size of the global
+offset table.
+
+GCC normally uses a single instruction to load values from the GOT@.
+While this is relatively efficient, it only works if the GOT
+is smaller than about 64k.  Anything larger causes the linker
+to report an error such as:
+
+@cindex relocation truncated to fit (MIPS)
+@smallexample
+relocation truncated to fit: R_MIPS_GOT16 foobar
+@end smallexample
+
+If this happens, you should recompile your code with @option{-mxgot}.
+This works with very large GOTs, although the code is also
+less efficient, since it takes three instructions to fetch the
+value of a global symbol.
+
+Note that some linkers can create multiple GOTs.  If you have such a
+linker, you should only need to use @option{-mxgot} when a single object
+file accesses more than 64k's worth of GOT entries.  Very few do.
+
+These options have no effect unless GCC is generating position
+independent code.
+
+@item -mgp32
+@opindex mgp32
+Assume that general-purpose registers are 32 bits wide.
+
+@item -mgp64
+@opindex mgp64
+Assume that general-purpose registers are 64 bits wide.
+
+@item -mfp32
+@opindex mfp32
+Assume that floating-point registers are 32 bits wide.
+
+@item -mfp64
+@opindex mfp64
+Assume that floating-point registers are 64 bits wide.
+
+@item -mhard-float
+@opindex mhard-float
+Use floating-point coprocessor instructions.
+
+@item -msoft-float
+@opindex msoft-float
+Do not use floating-point coprocessor instructions.  Implement
+floating-point calculations using library calls instead.
+
+@item -mno-float
+@opindex mno-float
+Equivalent to @option{-msoft-float}, but additionally asserts that the
+program being compiled does not perform any floating-point operations.
+This option is presently supported only by some bare-metal MIPS
+configurations, where it may select a special set of libraries
+that lack all floating-point support (including, for example, the
+floating-point @code{printf} formats).  
+If code compiled with @code{-mno-float} accidentally contains
+floating-point operations, it is likely to suffer a link-time
+or run-time failure.
+
+@item -msingle-float
+@opindex msingle-float
+Assume that the floating-point coprocessor only supports single-precision
+operations.
+
+@item -mdouble-float
+@opindex mdouble-float
+Assume that the floating-point coprocessor supports double-precision
+operations.  This is the default.
+
+@item -mllsc
+@itemx -mno-llsc
+@opindex mllsc
+@opindex mno-llsc
+Use (do not use) @samp{ll}, @samp{sc}, and @samp{sync} instructions to
+implement atomic memory built-in functions.  When neither option is
+specified, GCC uses the instructions if the target architecture
+supports them.
+
+@option{-mllsc} is useful if the runtime environment can emulate the
+instructions and @option{-mno-llsc} can be useful when compiling for
+nonstandard ISAs.  You can make either option the default by
+configuring GCC with @option{--with-llsc} and @option{--without-llsc}
+respectively.  @option{--with-llsc} is the default for some
+configurations; see the installation documentation for details.
+
+@item -mdsp
+@itemx -mno-dsp
+@opindex mdsp
+@opindex mno-dsp
+Use (do not use) revision 1 of the MIPS DSP ASE@.
+@xref{MIPS DSP Built-in Functions}.  This option defines the
+preprocessor macro @samp{__mips_dsp}.  It also defines
+@samp{__mips_dsp_rev} to 1.
+
+@item -mdspr2
+@itemx -mno-dspr2
+@opindex mdspr2
+@opindex mno-dspr2
+Use (do not use) revision 2 of the MIPS DSP ASE@.
+@xref{MIPS DSP Built-in Functions}.  This option defines the
+preprocessor macros @samp{__mips_dsp} and @samp{__mips_dspr2}.
+It also defines @samp{__mips_dsp_rev} to 2.
+
+@item -msmartmips
+@itemx -mno-smartmips
+@opindex msmartmips
+@opindex mno-smartmips
+Use (do not use) the MIPS SmartMIPS ASE.
+
+@item -mpaired-single
+@itemx -mno-paired-single
+@opindex mpaired-single
+@opindex mno-paired-single
+Use (do not use) paired-single floating-point instructions.
+@xref{MIPS Paired-Single Support}.  This option requires
+hardware floating-point support to be enabled.
+
+@item -mdmx
+@itemx -mno-mdmx
+@opindex mdmx
+@opindex mno-mdmx
+Use (do not use) MIPS Digital Media Extension instructions.
+This option can only be used when generating 64-bit code and requires
+hardware floating-point support to be enabled.
+
+@item -mips3d
+@itemx -mno-mips3d
+@opindex mips3d
+@opindex mno-mips3d
+Use (do not use) the MIPS-3D ASE@.  @xref{MIPS-3D Built-in Functions}.
+The option @option{-mips3d} implies @option{-mpaired-single}.
+
+@item -mmt
+@itemx -mno-mt
+@opindex mmt
+@opindex mno-mt
+Use (do not use) MT Multithreading instructions.
+
+@item -mmcu
+@itemx -mno-mcu
+@opindex mmcu
+@opindex mno-mcu
+Use (do not use) the MIPS MCU ASE instructions.
+
+@item -mlong64
+@opindex mlong64
+Force @code{long} types to be 64 bits wide.  See @option{-mlong32} for
+an explanation of the default and the way that the pointer size is
+determined.
+
+@item -mlong32
+@opindex mlong32
+Force @code{long}, @code{int}, and pointer types to be 32 bits wide.
+
+The default size of @code{int}s, @code{long}s and pointers depends on
+the ABI@.  All the supported ABIs use 32-bit @code{int}s.  The n64 ABI
+uses 64-bit @code{long}s, as does the 64-bit EABI; the others use
+32-bit @code{long}s.  Pointers are the same size as @code{long}s,
+or the same size as integer registers, whichever is smaller.
+
+@item -msym32
+@itemx -mno-sym32
+@opindex msym32
+@opindex mno-sym32
+Assume (do not assume) that all symbols have 32-bit values, regardless
+of the selected ABI@.  This option is useful in combination with
+@option{-mabi=64} and @option{-mno-abicalls} because it allows GCC
+to generate shorter and faster references to symbolic addresses.
+
+@item -G @var{num}
+@opindex G
+Put definitions of externally-visible data in a small data section
+if that data is no bigger than @var{num} bytes.  GCC can then generate
+more efficient accesses to the data; see @option{-mgpopt} for details.
+
+The default @option{-G} option depends on the configuration.
+
+@item -mlocal-sdata
+@itemx -mno-local-sdata
+@opindex mlocal-sdata
+@opindex mno-local-sdata
+Extend (do not extend) the @option{-G} behavior to local data too,
+such as to static variables in C@.  @option{-mlocal-sdata} is the
+default for all configurations.
+
+If the linker complains that an application is using too much small data,
+you might want to try rebuilding the less performance-critical parts with
+@option{-mno-local-sdata}.  You might also want to build large
+libraries with @option{-mno-local-sdata}, so that the libraries leave
+more room for the main program.
+
+@item -mextern-sdata
+@itemx -mno-extern-sdata
+@opindex mextern-sdata
+@opindex mno-extern-sdata
+Assume (do not assume) that externally-defined data is in
+a small data section if the size of that data is within the @option{-G} limit.
+@option{-mextern-sdata} is the default for all configurations.
+
+If you compile a module @var{Mod} with @option{-mextern-sdata} @option{-G
+@var{num}} @option{-mgpopt}, and @var{Mod} references a variable @var{Var}
+that is no bigger than @var{num} bytes, you must make sure that @var{Var}
+is placed in a small data section.  If @var{Var} is defined by another
+module, you must either compile that module with a high-enough
+@option{-G} setting or attach a @code{section} attribute to @var{Var}'s
+definition.  If @var{Var} is common, you must link the application
+with a high-enough @option{-G} setting.
+
+The easiest way of satisfying these restrictions is to compile
+and link every module with the same @option{-G} option.  However,
+you may wish to build a library that supports several different
+small data limits.  You can do this by compiling the library with
+the highest supported @option{-G} setting and additionally using
+@option{-mno-extern-sdata} to stop the library from making assumptions
+about externally-defined data.
+
+@item -mgpopt
+@itemx -mno-gpopt
+@opindex mgpopt
+@opindex mno-gpopt
+Use (do not use) GP-relative accesses for symbols that are known to be
+in a small data section; see @option{-G}, @option{-mlocal-sdata} and
+@option{-mextern-sdata}.  @option{-mgpopt} is the default for all
+configurations.
+
+@option{-mno-gpopt} is useful for cases where the @code{$gp} register
+might not hold the value of @code{_gp}.  For example, if the code is
+part of a library that might be used in a boot monitor, programs that
+call boot monitor routines pass an unknown value in @code{$gp}.
+(In such situations, the boot monitor itself is usually compiled
+with @option{-G0}.)
+
+@option{-mno-gpopt} implies @option{-mno-local-sdata} and
+@option{-mno-extern-sdata}.
+
+@item -membedded-data
+@itemx -mno-embedded-data
+@opindex membedded-data
+@opindex mno-embedded-data
+Allocate variables to the read-only data section first if possible, then
+next in the small data section if possible, otherwise in data.  This gives
+slightly slower code than the default, but reduces the amount of RAM required
+when executing, and thus may be preferred for some embedded systems.
+
+@item -muninit-const-in-rodata
+@itemx -mno-uninit-const-in-rodata
+@opindex muninit-const-in-rodata
+@opindex mno-uninit-const-in-rodata
+Put uninitialized @code{const} variables in the read-only data section.
+This option is only meaningful in conjunction with @option{-membedded-data}.
+
+@item -mcode-readable=@var{setting}
+@opindex mcode-readable
+Specify whether GCC may generate code that reads from executable sections.
+There are three possible settings:
+
+@table @gcctabopt
+@item -mcode-readable=yes
+Instructions may freely access executable sections.  This is the
+default setting.
+
+@item -mcode-readable=pcrel
+MIPS16 PC-relative load instructions can access executable sections,
+but other instructions must not do so.  This option is useful on 4KSc
+and 4KSd processors when the code TLBs have the Read Inhibit bit set.
+It is also useful on processors that can be configured to have a dual
+instruction/data SRAM interface and that, like the M4K, automatically
+redirect PC-relative loads to the instruction RAM.
+
+@item -mcode-readable=no
+Instructions must not access executable sections.  This option can be
+useful on targets that are configured to have a dual instruction/data
+SRAM interface but that (unlike the M4K) do not automatically redirect
+PC-relative loads to the instruction RAM.
+@end table
+
+@item -msplit-addresses
+@itemx -mno-split-addresses
+@opindex msplit-addresses
+@opindex mno-split-addresses
+Enable (disable) use of the @code{%hi()} and @code{%lo()} assembler
+relocation operators.  This option has been superseded by
+@option{-mexplicit-relocs} but is retained for backwards compatibility.
+
+@item -mexplicit-relocs
+@itemx -mno-explicit-relocs
+@opindex mexplicit-relocs
+@opindex mno-explicit-relocs
+Use (do not use) assembler relocation operators when dealing with symbolic
+addresses.  The alternative, selected by @option{-mno-explicit-relocs},
+is to use assembler macros instead.
+
+@option{-mexplicit-relocs} is the default if GCC was configured
+to use an assembler that supports relocation operators.
+
+@item -mcheck-zero-division
+@itemx -mno-check-zero-division
+@opindex mcheck-zero-division
+@opindex mno-check-zero-division
+Trap (do not trap) on integer division by zero.
+
+The default is @option{-mcheck-zero-division}.
+
+@item -mdivide-traps
+@itemx -mdivide-breaks
+@opindex mdivide-traps
+@opindex mdivide-breaks
+MIPS systems check for division by zero by generating either a
+conditional trap or a break instruction.  Using traps results in
+smaller code, but is only supported on MIPS II and later.  Also, some
+versions of the Linux kernel have a bug that prevents trap from
+generating the proper signal (@code{SIGFPE}).  Use @option{-mdivide-traps} to
+allow conditional traps on architectures that support them and
+@option{-mdivide-breaks} to force the use of breaks.
+
+The default is usually @option{-mdivide-traps}, but this can be
+overridden at configure time using @option{--with-divide=breaks}.
+Divide-by-zero checks can be completely disabled using
+@option{-mno-check-zero-division}.
+
+@item -mmemcpy
+@itemx -mno-memcpy
+@opindex mmemcpy
+@opindex mno-memcpy
+Force (do not force) the use of @code{memcpy()} for non-trivial block
+moves.  The default is @option{-mno-memcpy}, which allows GCC to inline
+most constant-sized copies.
+
+@item -mlong-calls
+@itemx -mno-long-calls
+@opindex mlong-calls
+@opindex mno-long-calls
+Disable (do not disable) use of the @code{jal} instruction.  Calling
+functions using @code{jal} is more efficient but requires the caller
+and callee to be in the same 256 megabyte segment.
+
+This option has no effect on abicalls code.  The default is
+@option{-mno-long-calls}.
+
+@item -mmad
+@itemx -mno-mad
+@opindex mmad
+@opindex mno-mad
+Enable (disable) use of the @code{mad}, @code{madu} and @code{mul}
+instructions, as provided by the R4650 ISA@.
+
+@item -mfused-madd
+@itemx -mno-fused-madd
+@opindex mfused-madd
+@opindex mno-fused-madd
+Enable (disable) use of the floating-point multiply-accumulate
+instructions, when they are available.  The default is
+@option{-mfused-madd}.
+
+On the R8000 CPU when multiply-accumulate instructions are used,
+the intermediate product is calculated to infinite precision
+and is not subject to the FCSR Flush to Zero bit.  This may be
+undesirable in some circumstances.  On other processors the result
+is numerically identical to the equivalent computation using
+separate multiply, add, subtract and negate instructions.
+
+@item -nocpp
+@opindex nocpp
+Tell the MIPS assembler to not run its preprocessor over user
+assembler files (with a @samp{.s} suffix) when assembling them.
+
+@item -mfix-24k
+@item -mno-fix-24k
+@opindex mfix-24k
+@opindex mno-fix-24k
+Work around the 24K E48 (lost data on stores during refill) errata.
+The workarounds are implemented by the assembler rather than by GCC@.
+
+@item -mfix-r4000
+@itemx -mno-fix-r4000
+@opindex mfix-r4000
+@opindex mno-fix-r4000
+Work around certain R4000 CPU errata:
+@itemize @minus
+@item
+A double-word or a variable shift may give an incorrect result if executed
+immediately after starting an integer division.
+@item
+A double-word or a variable shift may give an incorrect result if executed
+while an integer multiplication is in progress.
+@item
+An integer division may give an incorrect result if started in a delay slot
+of a taken branch or a jump.
+@end itemize
+
+@item -mfix-r4400
+@itemx -mno-fix-r4400
+@opindex mfix-r4400
+@opindex mno-fix-r4400
+Work around certain R4400 CPU errata:
+@itemize @minus
+@item
+A double-word or a variable shift may give an incorrect result if executed
+immediately after starting an integer division.
+@end itemize
+
+@item -mfix-r10000
+@itemx -mno-fix-r10000
+@opindex mfix-r10000
+@opindex mno-fix-r10000
+Work around certain R10000 errata:
+@itemize @minus
+@item
+@code{ll}/@code{sc} sequences may not behave atomically on revisions
+prior to 3.0.  They may deadlock on revisions 2.6 and earlier.
+@end itemize
+
+This option can only be used if the target architecture supports
+branch-likely instructions.  @option{-mfix-r10000} is the default when
+@option{-march=r10000} is used; @option{-mno-fix-r10000} is the default
+otherwise.
+
+@item -mfix-vr4120
+@itemx -mno-fix-vr4120
+@opindex mfix-vr4120
+Work around certain VR4120 errata:
+@itemize @minus
+@item
+@code{dmultu} does not always produce the correct result.
+@item
+@code{div} and @code{ddiv} do not always produce the correct result if one
+of the operands is negative.
+@end itemize
+The workarounds for the division errata rely on special functions in
+@file{libgcc.a}.  At present, these functions are only provided by
+the @code{mips64vr*-elf} configurations.
+
+Other VR4120 errata require a NOP to be inserted between certain pairs of
+instructions.  These errata are handled by the assembler, not by GCC itself.
+
+@item -mfix-vr4130
+@opindex mfix-vr4130
+Work around the VR4130 @code{mflo}/@code{mfhi} errata.  The
+workarounds are implemented by the assembler rather than by GCC,
+although GCC avoids using @code{mflo} and @code{mfhi} if the
+VR4130 @code{macc}, @code{macchi}, @code{dmacc} and @code{dmacchi}
+instructions are available instead.
+
+@item -mfix-sb1
+@itemx -mno-fix-sb1
+@opindex mfix-sb1
+Work around certain SB-1 CPU core errata.
+(This flag currently works around the SB-1 revision 2
+``F1'' and ``F2'' floating-point errata.)
+
+@item -mr10k-cache-barrier=@var{setting}
+@opindex mr10k-cache-barrier
+Specify whether GCC should insert cache barriers to avoid the
+side-effects of speculation on R10K processors.
+
+In common with many processors, the R10K tries to predict the outcome
+of a conditional branch and speculatively executes instructions from
+the ``taken'' branch.  It later aborts these instructions if the
+predicted outcome is wrong.  However, on the R10K, even aborted
+instructions can have side effects.
+
+This problem only affects kernel stores and, depending on the system,
+kernel loads.  As an example, a speculatively-executed store may load
+the target memory into cache and mark the cache line as dirty, even if
+the store itself is later aborted.  If a DMA operation writes to the
+same area of memory before the ``dirty'' line is flushed, the cached
+data overwrites the DMA-ed data.  See the R10K processor manual
+for a full description, including other potential problems.
+
+One workaround is to insert cache barrier instructions before every memory
+access that might be speculatively executed and that might have side
+effects even if aborted.  @option{-mr10k-cache-barrier=@var{setting}}
+controls GCC's implementation of this workaround.  It assumes that
+aborted accesses to any byte in the following regions does not have
+side effects:
+
+@enumerate
+@item
+the memory occupied by the current function's stack frame;
+
+@item
+the memory occupied by an incoming stack argument;
+
+@item
+the memory occupied by an object with a link-time-constant address.
+@end enumerate
+
+It is the kernel's responsibility to ensure that speculative
+accesses to these regions are indeed safe.
+
+If the input program contains a function declaration such as:
+
+@smallexample
+void foo (void);
+@end smallexample
+
+then the implementation of @code{foo} must allow @code{j foo} and
+@code{jal foo} to be executed speculatively.  GCC honors this
+restriction for functions it compiles itself.  It expects non-GCC
+functions (such as hand-written assembly code) to do the same.
+
+The option has three forms:
+
+@table @gcctabopt
+@item -mr10k-cache-barrier=load-store
+Insert a cache barrier before a load or store that might be
+speculatively executed and that might have side effects even
+if aborted.
+
+@item -mr10k-cache-barrier=store
+Insert a cache barrier before a store that might be speculatively
+executed and that might have side effects even if aborted.
+
+@item -mr10k-cache-barrier=none
+Disable the insertion of cache barriers.  This is the default setting.
+@end table
+
+@item -mflush-func=@var{func}
+@itemx -mno-flush-func
+@opindex mflush-func
+Specifies the function to call to flush the I and D caches, or to not
+call any such function.  If called, the function must take the same
+arguments as the common @code{_flush_func()}, that is, the address of the
+memory range for which the cache is being flushed, the size of the
+memory range, and the number 3 (to flush both caches).  The default
+depends on the target GCC was configured for, but commonly is either
+@samp{_flush_func} or @samp{__cpu_flush}.
+
+@item mbranch-cost=@var{num}
+@opindex mbranch-cost
+Set the cost of branches to roughly @var{num} ``simple'' instructions.
+This cost is only a heuristic and is not guaranteed to produce
+consistent results across releases.  A zero cost redundantly selects
+the default, which is based on the @option{-mtune} setting.
+
+@item -mbranch-likely
+@itemx -mno-branch-likely
+@opindex mbranch-likely
+@opindex mno-branch-likely
+Enable or disable use of Branch Likely instructions, regardless of the
+default for the selected architecture.  By default, Branch Likely
+instructions may be generated if they are supported by the selected
+architecture.  An exception is for the MIPS32 and MIPS64 architectures
+and processors that implement those architectures; for those, Branch
+Likely instructions are not be generated by default because the MIPS32
+and MIPS64 architectures specifically deprecate their use.
+
+@item -mfp-exceptions
+@itemx -mno-fp-exceptions
+@opindex mfp-exceptions
+Specifies whether FP exceptions are enabled.  This affects how
+FP instructions are scheduled for some processors.
+The default is that FP exceptions are
+enabled.
+
+For instance, on the SB-1, if FP exceptions are disabled, and we are emitting
+64-bit code, then we can use both FP pipes.  Otherwise, we can only use one
+FP pipe.
+
+@item -mvr4130-align
+@itemx -mno-vr4130-align
+@opindex mvr4130-align
+The VR4130 pipeline is two-way superscalar, but can only issue two
+instructions together if the first one is 8-byte aligned.  When this
+option is enabled, GCC aligns pairs of instructions that it
+thinks should execute in parallel.
+
+This option only has an effect when optimizing for the VR4130.
+It normally makes code faster, but at the expense of making it bigger.
+It is enabled by default at optimization level @option{-O3}.
+
+@item -msynci
+@itemx -mno-synci
+@opindex msynci
+Enable (disable) generation of @code{synci} instructions on
+architectures that support it.  The @code{synci} instructions (if
+enabled) are generated when @code{__builtin___clear_cache()} is
+compiled.
+
+This option defaults to @code{-mno-synci}, but the default can be
+overridden by configuring with @code{--with-synci}.
+
+When compiling code for single processor systems, it is generally safe
+to use @code{synci}.  However, on many multi-core (SMP) systems, it
+does not invalidate the instruction caches on all cores and may lead
+to undefined behavior.
+
+@item -mrelax-pic-calls
+@itemx -mno-relax-pic-calls
+@opindex mrelax-pic-calls
+Try to turn PIC calls that are normally dispatched via register
+@code{$25} into direct calls.  This is only possible if the linker can
+resolve the destination at link-time and if the destination is within
+range for a direct call.
+
+@option{-mrelax-pic-calls} is the default if GCC was configured to use
+an assembler and a linker that support the @code{.reloc} assembly
+directive and @code{-mexplicit-relocs} is in effect.  With
+@code{-mno-explicit-relocs}, this optimization can be performed by the
+assembler and the linker alone without help from the compiler.
+
+@item -mmcount-ra-address
+@itemx -mno-mcount-ra-address
+@opindex mmcount-ra-address
+@opindex mno-mcount-ra-address
+Emit (do not emit) code that allows @code{_mcount} to modify the
+calling function's return address.  When enabled, this option extends
+the usual @code{_mcount} interface with a new @var{ra-address}
+parameter, which has type @code{intptr_t *} and is passed in register
+@code{$12}.  @code{_mcount} can then modify the return address by
+doing both of the following:
+@itemize
+@item
+Returning the new address in register @code{$31}.
+@item
+Storing the new address in @code{*@var{ra-address}},
+if @var{ra-address} is nonnull.
+@end itemize
+
+The default is @option{-mno-mcount-ra-address}.
+
+@end table
+
+@node MMIX Options
+@subsection MMIX Options
+@cindex MMIX Options
+
+These options are defined for the MMIX:
+
+@table @gcctabopt
+@item -mlibfuncs
+@itemx -mno-libfuncs
+@opindex mlibfuncs
+@opindex mno-libfuncs
+Specify that intrinsic library functions are being compiled, passing all
+values in registers, no matter the size.
+
+@item -mepsilon
+@itemx -mno-epsilon
+@opindex mepsilon
+@opindex mno-epsilon
+Generate floating-point comparison instructions that compare with respect
+to the @code{rE} epsilon register.
+
+@item -mabi=mmixware
+@itemx -mabi=gnu
+@opindex mabi=mmixware
+@opindex mabi=gnu
+Generate code that passes function parameters and return values that (in
+the called function) are seen as registers @code{$0} and up, as opposed to
+the GNU ABI which uses global registers @code{$231} and up.
+
+@item -mzero-extend
+@itemx -mno-zero-extend
+@opindex mzero-extend
+@opindex mno-zero-extend
+When reading data from memory in sizes shorter than 64 bits, use (do not
+use) zero-extending load instructions by default, rather than
+sign-extending ones.
+
+@item -mknuthdiv
+@itemx -mno-knuthdiv
+@opindex mknuthdiv
+@opindex mno-knuthdiv
+Make the result of a division yielding a remainder have the same sign as
+the divisor.  With the default, @option{-mno-knuthdiv}, the sign of the
+remainder follows the sign of the dividend.  Both methods are
+arithmetically valid, the latter being almost exclusively used.
+
+@item -mtoplevel-symbols
+@itemx -mno-toplevel-symbols
+@opindex mtoplevel-symbols
+@opindex mno-toplevel-symbols
+Prepend (do not prepend) a @samp{:} to all global symbols, so the assembly
+code can be used with the @code{PREFIX} assembly directive.
+
+@item -melf
+@opindex melf
+Generate an executable in the ELF format, rather than the default
+@samp{mmo} format used by the @command{mmix} simulator.
+
+@item -mbranch-predict
+@itemx -mno-branch-predict
+@opindex mbranch-predict
+@opindex mno-branch-predict
+Use (do not use) the probable-branch instructions, when static branch
+prediction indicates a probable branch.
+
+@item -mbase-addresses
+@itemx -mno-base-addresses
+@opindex mbase-addresses
+@opindex mno-base-addresses
+Generate (do not generate) code that uses @emph{base addresses}.  Using a
+base address automatically generates a request (handled by the assembler
+and the linker) for a constant to be set up in a global register.  The
+register is used for one or more base address requests within the range 0
+to 255 from the value held in the register.  The generally leads to short
+and fast code, but the number of different data items that can be
+addressed is limited.  This means that a program that uses lots of static
+data may require @option{-mno-base-addresses}.
+
+@item -msingle-exit
+@itemx -mno-single-exit
+@opindex msingle-exit
+@opindex mno-single-exit
+Force (do not force) generated code to have a single exit point in each
+function.
+@end table
+
+@node MN10300 Options
+@subsection MN10300 Options
+@cindex MN10300 options
+
+These @option{-m} options are defined for Matsushita MN10300 architectures:
+
+@table @gcctabopt
+@item -mmult-bug
+@opindex mmult-bug
+Generate code to avoid bugs in the multiply instructions for the MN10300
+processors.  This is the default.
+
+@item -mno-mult-bug
+@opindex mno-mult-bug
+Do not generate code to avoid bugs in the multiply instructions for the
+MN10300 processors.
+
+@item -mam33
+@opindex mam33
+Generate code using features specific to the AM33 processor.
+
+@item -mno-am33
+@opindex mno-am33
+Do not generate code using features specific to the AM33 processor.  This
+is the default.
+
+@item -mam33-2
+@opindex mam33-2
+Generate code using features specific to the AM33/2.0 processor.
+
+@item -mam34
+@opindex mam34
+Generate code using features specific to the AM34 processor.
+
+@item -mtune=@var{cpu-type}
+@opindex mtune
+Use the timing characteristics of the indicated CPU type when
+scheduling instructions.  This does not change the targeted processor
+type.  The CPU type must be one of @samp{mn10300}, @samp{am33},
+@samp{am33-2} or @samp{am34}.
+
+@item -mreturn-pointer-on-d0
+@opindex mreturn-pointer-on-d0
+When generating a function that returns a pointer, return the pointer
+in both @code{a0} and @code{d0}.  Otherwise, the pointer is returned
+only in @code{a0}, and attempts to call such functions without a prototype
+result in errors.  Note that this option is on by default; use
+@option{-mno-return-pointer-on-d0} to disable it.
+
+@item -mno-crt0
+@opindex mno-crt0
+Do not link in the C run-time initialization object file.
+
+@item -mrelax
+@opindex mrelax
+Indicate to the linker that it should perform a relaxation optimization pass
+to shorten branches, calls and absolute memory addresses.  This option only
+has an effect when used on the command line for the final link step.
+
+This option makes symbolic debugging impossible.
+
+@item -mliw
+@opindex mliw
+Allow the compiler to generate @emph{Long Instruction Word}
+instructions if the target is the @samp{AM33} or later.  This is the
+default.  This option defines the preprocessor macro @samp{__LIW__}.
+
+@item -mnoliw
+@opindex mnoliw
+Do not allow the compiler to generate @emph{Long Instruction Word}
+instructions.  This option defines the preprocessor macro
+@samp{__NO_LIW__}.
+
+@item -msetlb
+@opindex msetlb
+Allow the compiler to generate the @emph{SETLB} and @emph{Lcc}
+instructions if the target is the @samp{AM33} or later.  This is the
+default.  This option defines the preprocessor macro @samp{__SETLB__}.
+
+@item -mnosetlb
+@opindex mnosetlb
+Do not allow the compiler to generate @emph{SETLB} or @emph{Lcc}
+instructions.  This option defines the preprocessor macro
+@samp{__NO_SETLB__}.
+
+@end table
+
+@node Moxie Options
+@subsection Moxie Options
+@cindex Moxie Options
+
+@table @gcctabopt
+
+@item -meb
+@opindex meb
+Generate big-endian code.  This is the default for @samp{moxie-*-*}
+configurations.
+
+@item -mel
+@opindex mel
+Generate little-endian code.
+
+@item -mno-crt0
+@opindex mno-crt0
+Do not link in the C run-time initialization object file.
+
+@end table
+
+@node PDP-11 Options
+@subsection PDP-11 Options
+@cindex PDP-11 Options
+
+These options are defined for the PDP-11:
+
+@table @gcctabopt
+@item -mfpu
+@opindex mfpu
+Use hardware FPP floating point.  This is the default.  (FIS floating
+point on the PDP-11/40 is not supported.)
+
+@item -msoft-float
+@opindex msoft-float
+Do not use hardware floating point.
+
+@item -mac0
+@opindex mac0
+Return floating-point results in ac0 (fr0 in Unix assembler syntax).
+
+@item -mno-ac0
+@opindex mno-ac0
+Return floating-point results in memory.  This is the default.
+
+@item -m40
+@opindex m40
+Generate code for a PDP-11/40.
+
+@item -m45
+@opindex m45
+Generate code for a PDP-11/45.  This is the default.
+
+@item -m10
+@opindex m10
+Generate code for a PDP-11/10.
+
+@item -mbcopy-builtin
+@opindex mbcopy-builtin
+Use inline @code{movmemhi} patterns for copying memory.  This is the
+default.
+
+@item -mbcopy
+@opindex mbcopy
+Do not use inline @code{movmemhi} patterns for copying memory.
+
+@item -mint16
+@itemx -mno-int32
+@opindex mint16
+@opindex mno-int32
+Use 16-bit @code{int}.  This is the default.
+
+@item -mint32
+@itemx -mno-int16
+@opindex mint32
+@opindex mno-int16
+Use 32-bit @code{int}.
+
+@item -mfloat64
+@itemx -mno-float32
+@opindex mfloat64
+@opindex mno-float32
+Use 64-bit @code{float}.  This is the default.
+
+@item -mfloat32
+@itemx -mno-float64
+@opindex mfloat32
+@opindex mno-float64
+Use 32-bit @code{float}.
+
+@item -mabshi
+@opindex mabshi
+Use @code{abshi2} pattern.  This is the default.
+
+@item -mno-abshi
+@opindex mno-abshi
+Do not use @code{abshi2} pattern.
+
+@item -mbranch-expensive
+@opindex mbranch-expensive
+Pretend that branches are expensive.  This is for experimenting with
+code generation only.
+
+@item -mbranch-cheap
+@opindex mbranch-cheap
+Do not pretend that branches are expensive.  This is the default.
+
+@item -munix-asm
+@opindex munix-asm
+Use Unix assembler syntax.  This is the default when configured for
+@samp{pdp11-*-bsd}.
+
+@item -mdec-asm
+@opindex mdec-asm
+Use DEC assembler syntax.  This is the default when configured for any
+PDP-11 target other than @samp{pdp11-*-bsd}.
+@end table
+
+@node picoChip Options
+@subsection picoChip Options
+@cindex picoChip options
+
+These @samp{-m} options are defined for picoChip implementations:
+
+@table @gcctabopt
+
+@item -mae=@var{ae_type}
+@opindex mcpu
+Set the instruction set, register set, and instruction scheduling
+parameters for array element type @var{ae_type}.  Supported values
+for @var{ae_type} are @samp{ANY}, @samp{MUL}, and @samp{MAC}.
+
+@option{-mae=ANY} selects a completely generic AE type.  Code
+generated with this option runs on any of the other AE types.  The
+code is not as efficient as it would be if compiled for a specific
+AE type, and some types of operation (e.g., multiplication) do not
+work properly on all types of AE.
+
+@option{-mae=MUL} selects a MUL AE type.  This is the most useful AE type
+for compiled code, and is the default.
+
+@option{-mae=MAC} selects a DSP-style MAC AE.  Code compiled with this
+option may suffer from poor performance of byte (char) manipulation,
+since the DSP AE does not provide hardware support for byte load/stores.
+
+@item -msymbol-as-address
+Enable the compiler to directly use a symbol name as an address in a
+load/store instruction, without first loading it into a
+register.  Typically, the use of this option generates larger
+programs, which run faster than when the option isn't used.  However, the
+results vary from program to program, so it is left as a user option,
+rather than being permanently enabled.
+
+@item -mno-inefficient-warnings
+Disables warnings about the generation of inefficient code.  These
+warnings can be generated, for example, when compiling code that
+performs byte-level memory operations on the MAC AE type.  The MAC AE has
+no hardware support for byte-level memory operations, so all byte
+load/stores must be synthesized from word load/store operations.  This is
+inefficient and a warning is generated to indicate
+that you should rewrite the code to avoid byte operations, or to target
+an AE type that has the necessary hardware support.  This option disables
+these warnings.
+
+@end table
+
+@node PowerPC Options
+@subsection PowerPC Options
+@cindex PowerPC options
+
+These are listed under @xref{RS/6000 and PowerPC Options}.
+
+@node RL78 Options
+@subsection RL78 Options
+@cindex RL78 Options
+
+@table @gcctabopt
+
+@item -msim
+@opindex msim
+Links in additional target libraries to support operation within a
+simulator.
+
+@item -mmul=none
+@itemx -mmul=g13
+@itemx -mmul=rl78
+@opindex mmul
+Specifies the type of hardware multiplication support to be used.  The
+default is @code{none}, which uses software multiplication functions.
+The @code{g13} option is for the hardware multiply/divide peripheral
+only on the RL78/G13 targets.  The @code{rl78} option is for the
+standard hardware multiplication defined in the RL78 software manual.
+
+@end table
+
+@node RS/6000 and PowerPC Options
+@subsection IBM RS/6000 and PowerPC Options
+@cindex RS/6000 and PowerPC Options
+@cindex IBM RS/6000 and PowerPC Options
+
+These @samp{-m} options are defined for the IBM RS/6000 and PowerPC:
+@table @gcctabopt
+@item -mpowerpc-gpopt
+@itemx -mno-powerpc-gpopt
+@itemx -mpowerpc-gfxopt
+@itemx -mno-powerpc-gfxopt
+@need 800
+@itemx -mpowerpc64
+@itemx -mno-powerpc64
+@itemx -mmfcrf
+@itemx -mno-mfcrf
+@itemx -mpopcntb
+@itemx -mno-popcntb
+@itemx -mpopcntd
+@itemx -mno-popcntd
+@itemx -mfprnd
+@itemx -mno-fprnd
+@need 800
+@itemx -mcmpb
+@itemx -mno-cmpb
+@itemx -mmfpgpr
+@itemx -mno-mfpgpr
+@itemx -mhard-dfp
+@itemx -mno-hard-dfp
+@opindex mpowerpc-gpopt
+@opindex mno-powerpc-gpopt
+@opindex mpowerpc-gfxopt
+@opindex mno-powerpc-gfxopt
+@opindex mpowerpc64
+@opindex mno-powerpc64
+@opindex mmfcrf
+@opindex mno-mfcrf
+@opindex mpopcntb
+@opindex mno-popcntb
+@opindex mpopcntd
+@opindex mno-popcntd
+@opindex mfprnd
+@opindex mno-fprnd
+@opindex mcmpb
+@opindex mno-cmpb
+@opindex mmfpgpr
+@opindex mno-mfpgpr
+@opindex mhard-dfp
+@opindex mno-hard-dfp
+You use these options to specify which instructions are available on the
+processor you are using.  The default value of these options is
+determined when configuring GCC@.  Specifying the
+@option{-mcpu=@var{cpu_type}} overrides the specification of these
+options.  We recommend you use the @option{-mcpu=@var{cpu_type}} option
+rather than the options listed above.
+
+Specifying @option{-mpowerpc-gpopt} allows
+GCC to use the optional PowerPC architecture instructions in the
+General Purpose group, including floating-point square root.  Specifying
+@option{-mpowerpc-gfxopt} allows GCC to
+use the optional PowerPC architecture instructions in the Graphics
+group, including floating-point select.
+
+The @option{-mmfcrf} option allows GCC to generate the move from
+condition register field instruction implemented on the POWER4
+processor and other processors that support the PowerPC V2.01
+architecture.
+The @option{-mpopcntb} option allows GCC to generate the popcount and
+double-precision FP reciprocal estimate instruction implemented on the
+POWER5 processor and other processors that support the PowerPC V2.02
+architecture.
+The @option{-mpopcntd} option allows GCC to generate the popcount
+instruction implemented on the POWER7 processor and other processors
+that support the PowerPC V2.06 architecture.
+The @option{-mfprnd} option allows GCC to generate the FP round to
+integer instructions implemented on the POWER5+ processor and other
+processors that support the PowerPC V2.03 architecture.
+The @option{-mcmpb} option allows GCC to generate the compare bytes
+instruction implemented on the POWER6 processor and other processors
+that support the PowerPC V2.05 architecture.
+The @option{-mmfpgpr} option allows GCC to generate the FP move to/from
+general-purpose register instructions implemented on the POWER6X
+processor and other processors that support the extended PowerPC V2.05
+architecture.
+The @option{-mhard-dfp} option allows GCC to generate the decimal
+floating-point instructions implemented on some POWER processors.
+
+The @option{-mpowerpc64} option allows GCC to generate the additional
+64-bit instructions that are found in the full PowerPC64 architecture
+and to treat GPRs as 64-bit, doubleword quantities.  GCC defaults to
+@option{-mno-powerpc64}.
+
+@item -mcpu=@var{cpu_type}
+@opindex mcpu
+Set architecture type, register usage, and
+instruction scheduling parameters for machine type @var{cpu_type}.
+Supported values for @var{cpu_type} are @samp{401}, @samp{403},
+@samp{405}, @samp{405fp}, @samp{440}, @samp{440fp}, @samp{464}, @samp{464fp},
+@samp{476}, @samp{476fp}, @samp{505}, @samp{601}, @samp{602}, @samp{603},
+@samp{603e}, @samp{604}, @samp{604e}, @samp{620}, @samp{630}, @samp{740},
+@samp{7400}, @samp{7450}, @samp{750}, @samp{801}, @samp{821}, @samp{823},
+@samp{860}, @samp{970}, @samp{8540}, @samp{a2}, @samp{e300c2},
+@samp{e300c3}, @samp{e500mc}, @samp{e500mc64}, @samp{e5500},
+@samp{e6500}, @samp{ec603e}, @samp{G3}, @samp{G4}, @samp{G5},
+@samp{titan}, @samp{power3}, @samp{power4}, @samp{power5}, @samp{power5+},
+@samp{power6}, @samp{power6x}, @samp{power7}, @samp{power8}, @samp{powerpc},
+@samp{powerpc64}, and @samp{rs64}.
+
+@option{-mcpu=powerpc}, and @option{-mcpu=powerpc64} specify pure 32-bit
+PowerPC and 64-bit PowerPC architecture machine
+types, with an appropriate, generic processor model assumed for
+scheduling purposes.
+
+The other options specify a specific processor.  Code generated under
+those options runs best on that processor, and may not run at all on
+others.
+
+The @option{-mcpu} options automatically enable or disable the
+following options:
+
+@gccoptlist{-maltivec  -mfprnd  -mhard-float  -mmfcrf  -mmultiple @gol
+-mpopcntb -mpopcntd  -mpowerpc64 @gol
+-mpowerpc-gpopt  -mpowerpc-gfxopt  -msingle-float -mdouble-float @gol
+-msimple-fpu -mstring  -mmulhw  -mdlmzb  -mmfpgpr -mvsx @gol
+-mcrypto -mdirect-move -mpower8-fusion -mpower8-vector @gol
+-mquad-memory -mquad-memory-atomic}
+
+The particular options set for any particular CPU varies between
+compiler versions, depending on what setting seems to produce optimal
+code for that CPU; it doesn't necessarily reflect the actual hardware's
+capabilities.  If you wish to set an individual option to a particular
+value, you may specify it after the @option{-mcpu} option, like
+@option{-mcpu=970 -mno-altivec}.
+
+On AIX, the @option{-maltivec} and @option{-mpowerpc64} options are
+not enabled or disabled by the @option{-mcpu} option at present because
+AIX does not have full support for these options.  You may still
+enable or disable them individually if you're sure it'll work in your
+environment.
+
+@item -mtune=@var{cpu_type}
+@opindex mtune
+Set the instruction scheduling parameters for machine type
+@var{cpu_type}, but do not set the architecture type or register usage,
+as @option{-mcpu=@var{cpu_type}} does.  The same
+values for @var{cpu_type} are used for @option{-mtune} as for
+@option{-mcpu}.  If both are specified, the code generated uses the
+architecture and registers set by @option{-mcpu}, but the
+scheduling parameters set by @option{-mtune}.
+
+@item -mcmodel=small
+@opindex mcmodel=small
+Generate PowerPC64 code for the small model: The TOC is limited to
+64k.
+
+@item -mcmodel=medium
+@opindex mcmodel=medium
+Generate PowerPC64 code for the medium model: The TOC and other static
+data may be up to a total of 4G in size.
+
+@item -mcmodel=large
+@opindex mcmodel=large
+Generate PowerPC64 code for the large model: The TOC may be up to 4G
+in size.  Other data and code is only limited by the 64-bit address
+space.
+
+@item -maltivec
+@itemx -mno-altivec
+@opindex maltivec
+@opindex mno-altivec
+Generate code that uses (does not use) AltiVec instructions, and also
+enable the use of built-in functions that allow more direct access to
+the AltiVec instruction set.  You may also need to set
+@option{-mabi=altivec} to adjust the current ABI with AltiVec ABI
+enhancements.
+
+When @option{-maltivec} is used, rather than @option{-maltivec=le} or
+@option{-maltivec=be}, the element order for Altivec intrinsics such
+as @code{vec_splat}, @code{vec_extract}, and @code{vec_insert} will
+match array element order corresponding to the endianness of the
+target.  That is, element zero identifies the leftmost element in a
+vector register when targeting a big-endian platform, and identifies
+the rightmost element in a vector register when targeting a
+little-endian platform.
+
+@item -maltivec=be
+@opindex maltivec=be
+Generate Altivec instructions using big-endian element order,
+regardless of whether the target is big- or little-endian.  This is
+the default when targeting a big-endian platform.
+
+The element order is used to interpret element numbers in Altivec
+intrinsics such as @code{vec_splat}, @code{vec_extract}, and
+@code{vec_insert}.  By default, these will match array element order
+corresponding to the endianness for the target.
+
+@item -maltivec=le
+@opindex maltivec=le
+Generate Altivec instructions using little-endian element order,
+regardless of whether the target is big- or little-endian.  This is
+the default when targeting a little-endian platform.  This option is
+currently ignored when targeting a big-endian platform.
+
+The element order is used to interpret element numbers in Altivec
+intrinsics such as @code{vec_splat}, @code{vec_extract}, and
+@code{vec_insert}.  By default, these will match array element order
+corresponding to the endianness for the target.
+
+@item -mvrsave
+@itemx -mno-vrsave
+@opindex mvrsave
+@opindex mno-vrsave
+Generate VRSAVE instructions when generating AltiVec code.
+
+@item -mgen-cell-microcode
+@opindex mgen-cell-microcode
+Generate Cell microcode instructions.
+
+@item -mwarn-cell-microcode
+@opindex mwarn-cell-microcode
+Warn when a Cell microcode instruction is emitted.  An example
+of a Cell microcode instruction is a variable shift.
+
+@item -msecure-plt
+@opindex msecure-plt
+Generate code that allows @command{ld} and @command{ld.so}
+to build executables and shared
+libraries with non-executable @code{.plt} and @code{.got} sections.
+This is a PowerPC
+32-bit SYSV ABI option.
+
+@item -mbss-plt
+@opindex mbss-plt
+Generate code that uses a BSS @code{.plt} section that @command{ld.so}
+fills in, and
+requires @code{.plt} and @code{.got}
+sections that are both writable and executable.
+This is a PowerPC 32-bit SYSV ABI option.
+
+@item -misel
+@itemx -mno-isel
+@opindex misel
+@opindex mno-isel
+This switch enables or disables the generation of ISEL instructions.
+
+@item -misel=@var{yes/no}
+This switch has been deprecated.  Use @option{-misel} and
+@option{-mno-isel} instead.
+
+@item -mspe
+@itemx -mno-spe
+@opindex mspe
+@opindex mno-spe
+This switch enables or disables the generation of SPE simd
+instructions.
+
+@item -mpaired
+@itemx -mno-paired
+@opindex mpaired
+@opindex mno-paired
+This switch enables or disables the generation of PAIRED simd
+instructions.
+
+@item -mspe=@var{yes/no}
+This option has been deprecated.  Use @option{-mspe} and
+@option{-mno-spe} instead.
+
+@item -mvsx
+@itemx -mno-vsx
+@opindex mvsx
+@opindex mno-vsx
+Generate code that uses (does not use) vector/scalar (VSX)
+instructions, and also enable the use of built-in functions that allow
+more direct access to the VSX instruction set.
+
+@item -mcrypto
+@itemx -mno-crypto
+@opindex mcrypto
+@opindex mno-crypto
+Enable the use (disable) of the built-in functions that allow direct
+access to the cryptographic instructions that were added in version
+2.07 of the PowerPC ISA.
+
+@item -mdirect-move
+@itemx -mno-direct-move
+@opindex mdirect-move
+@opindex mno-direct-move
+Generate code that uses (does not use) the instructions to move data
+between the general purpose registers and the vector/scalar (VSX)
+registers that were added in version 2.07 of the PowerPC ISA.
+
+@item -mpower8-fusion
+@itemx -mno-power8-fusion
+@opindex mpower8-fusion
+@opindex mno-power8-fusion
+Generate code that keeps (does not keeps) some integer operations
+adjacent so that the instructions can be fused together on power8 and
+later processors.
+
+@item -mpower8-vector
+@itemx -mno-power8-vector
+@opindex mpower8-vector
+@opindex mno-power8-vector
+Generate code that uses (does not use) the vector and scalar
+instructions that were added in version 2.07 of the PowerPC ISA.  Also
+enable the use of built-in functions that allow more direct access to
+the vector instructions.
+
+@item -mquad-memory
+@itemx -mno-quad-memory
+@opindex mquad-memory
+@opindex mno-quad-memory
+Generate code that uses (does not use) the non-atomic quad word memory
+instructions.  The @option{-mquad-memory} option requires use of
+64-bit mode.
+
+@item -mquad-memory-atomic
+@itemx -mno-quad-memory-atomic
+@opindex mquad-memory-atomic
+@opindex mno-quad-memory-atomic
+Generate code that uses (does not use) the atomic quad word memory
+instructions.  The @option{-mquad-memory-atomic} option requires use of
+64-bit mode.
+
+@item -mfloat-gprs=@var{yes/single/double/no}
+@itemx -mfloat-gprs
+@opindex mfloat-gprs
+This switch enables or disables the generation of floating-point
+operations on the general-purpose registers for architectures that
+support it.
+
+The argument @var{yes} or @var{single} enables the use of
+single-precision floating-point operations.
+
+The argument @var{double} enables the use of single and
+double-precision floating-point operations.
+
+The argument @var{no} disables floating-point operations on the
+general-purpose registers.
+
+This option is currently only available on the MPC854x.
+
+@item -m32
+@itemx -m64
+@opindex m32
+@opindex m64
+Generate code for 32-bit or 64-bit environments of Darwin and SVR4
+targets (including GNU/Linux).  The 32-bit environment sets int, long
+and pointer to 32 bits and generates code that runs on any PowerPC
+variant.  The 64-bit environment sets int to 32 bits and long and
+pointer to 64 bits, and generates code for PowerPC64, as for
+@option{-mpowerpc64}.
+
+@item -mfull-toc
+@itemx -mno-fp-in-toc
+@itemx -mno-sum-in-toc
+@itemx -mminimal-toc
+@opindex mfull-toc
+@opindex mno-fp-in-toc
+@opindex mno-sum-in-toc
+@opindex mminimal-toc
+Modify generation of the TOC (Table Of Contents), which is created for
+every executable file.  The @option{-mfull-toc} option is selected by
+default.  In that case, GCC allocates at least one TOC entry for
+each unique non-automatic variable reference in your program.  GCC
+also places floating-point constants in the TOC@.  However, only
+16,384 entries are available in the TOC@.
+
+If you receive a linker error message that saying you have overflowed
+the available TOC space, you can reduce the amount of TOC space used
+with the @option{-mno-fp-in-toc} and @option{-mno-sum-in-toc} options.
+@option{-mno-fp-in-toc} prevents GCC from putting floating-point
+constants in the TOC and @option{-mno-sum-in-toc} forces GCC to
+generate code to calculate the sum of an address and a constant at
+run time instead of putting that sum into the TOC@.  You may specify one
+or both of these options.  Each causes GCC to produce very slightly
+slower and larger code at the expense of conserving TOC space.
+
+If you still run out of space in the TOC even when you specify both of
+these options, specify @option{-mminimal-toc} instead.  This option causes
+GCC to make only one TOC entry for every file.  When you specify this
+option, GCC produces code that is slower and larger but which
+uses extremely little TOC space.  You may wish to use this option
+only on files that contain less frequently-executed code.
+
+@item -maix64
+@itemx -maix32
+@opindex maix64
+@opindex maix32
+Enable 64-bit AIX ABI and calling convention: 64-bit pointers, 64-bit
+@code{long} type, and the infrastructure needed to support them.
+Specifying @option{-maix64} implies @option{-mpowerpc64},
+while @option{-maix32} disables the 64-bit ABI and
+implies @option{-mno-powerpc64}.  GCC defaults to @option{-maix32}.
+
+@item -mxl-compat
+@itemx -mno-xl-compat
+@opindex mxl-compat
+@opindex mno-xl-compat
+Produce code that conforms more closely to IBM XL compiler semantics
+when using AIX-compatible ABI@.  Pass floating-point arguments to
+prototyped functions beyond the register save area (RSA) on the stack
+in addition to argument FPRs.  Do not assume that most significant
+double in 128-bit long double value is properly rounded when comparing
+values and converting to double.  Use XL symbol names for long double
+support routines.
+
+The AIX calling convention was extended but not initially documented to
+handle an obscure K&R C case of calling a function that takes the
+address of its arguments with fewer arguments than declared.  IBM XL
+compilers access floating-point arguments that do not fit in the
+RSA from the stack when a subroutine is compiled without
+optimization.  Because always storing floating-point arguments on the
+stack is inefficient and rarely needed, this option is not enabled by
+default and only is necessary when calling subroutines compiled by IBM
+XL compilers without optimization.
+
+@item -mpe
+@opindex mpe
+Support @dfn{IBM RS/6000 SP} @dfn{Parallel Environment} (PE)@.  Link an
+application written to use message passing with special startup code to
+enable the application to run.  The system must have PE installed in the
+standard location (@file{/usr/lpp/ppe.poe/}), or the @file{specs} file
+must be overridden with the @option{-specs=} option to specify the
+appropriate directory location.  The Parallel Environment does not
+support threads, so the @option{-mpe} option and the @option{-pthread}
+option are incompatible.
+
+@item -malign-natural
+@itemx -malign-power
+@opindex malign-natural
+@opindex malign-power
+On AIX, 32-bit Darwin, and 64-bit PowerPC GNU/Linux, the option
+@option{-malign-natural} overrides the ABI-defined alignment of larger
+types, such as floating-point doubles, on their natural size-based boundary.
+The option @option{-malign-power} instructs GCC to follow the ABI-specified
+alignment rules.  GCC defaults to the standard alignment defined in the ABI@.
+
+On 64-bit Darwin, natural alignment is the default, and @option{-malign-power}
+is not supported.
+
+@item -msoft-float
+@itemx -mhard-float
+@opindex msoft-float
+@opindex mhard-float
+Generate code that does not use (uses) the floating-point register set.
+Software floating-point emulation is provided if you use the
+@option{-msoft-float} option, and pass the option to GCC when linking.
+
+@item -msingle-float
+@itemx -mdouble-float
+@opindex msingle-float
+@opindex mdouble-float
+Generate code for single- or double-precision floating-point operations.
+@option{-mdouble-float} implies @option{-msingle-float}.
+
+@item -msimple-fpu
+@opindex msimple-fpu
+Do not generate @code{sqrt} and @code{div} instructions for hardware
+floating-point unit.
+
+@item -mfpu=@var{name}
+@opindex mfpu
+Specify type of floating-point unit.  Valid values for @var{name} are
+@samp{sp_lite} (equivalent to @option{-msingle-float -msimple-fpu}),
+@samp{dp_lite} (equivalent to @option{-mdouble-float -msimple-fpu}),
+@samp{sp_full} (equivalent to @option{-msingle-float}),
+and @samp{dp_full} (equivalent to @option{-mdouble-float}).
+
+@item -mxilinx-fpu
+@opindex mxilinx-fpu
+Perform optimizations for the floating-point unit on Xilinx PPC 405/440.
+
+@item -mmultiple
+@itemx -mno-multiple
+@opindex mmultiple
+@opindex mno-multiple
+Generate code that uses (does not use) the load multiple word
+instructions and the store multiple word instructions.  These
+instructions are generated by default on POWER systems, and not
+generated on PowerPC systems.  Do not use @option{-mmultiple} on little-endian
+PowerPC systems, since those instructions do not work when the
+processor is in little-endian mode.  The exceptions are PPC740 and
+PPC750 which permit these instructions in little-endian mode.
+
+@item -mstring
+@itemx -mno-string
+@opindex mstring
+@opindex mno-string
+Generate code that uses (does not use) the load string instructions
+and the store string word instructions to save multiple registers and
+do small block moves.  These instructions are generated by default on
+POWER systems, and not generated on PowerPC systems.  Do not use
+@option{-mstring} on little-endian PowerPC systems, since those
+instructions do not work when the processor is in little-endian mode.
+The exceptions are PPC740 and PPC750 which permit these instructions
+in little-endian mode.
+
+@item -mupdate
+@itemx -mno-update
+@opindex mupdate
+@opindex mno-update
+Generate code that uses (does not use) the load or store instructions
+that update the base register to the address of the calculated memory
+location.  These instructions are generated by default.  If you use
+@option{-mno-update}, there is a small window between the time that the
+stack pointer is updated and the address of the previous frame is
+stored, which means code that walks the stack frame across interrupts or
+signals may get corrupted data.
+
+@item -mavoid-indexed-addresses
+@itemx -mno-avoid-indexed-addresses
+@opindex mavoid-indexed-addresses
+@opindex mno-avoid-indexed-addresses
+Generate code that tries to avoid (not avoid) the use of indexed load
+or store instructions. These instructions can incur a performance
+penalty on Power6 processors in certain situations, such as when
+stepping through large arrays that cross a 16M boundary.  This option
+is enabled by default when targeting Power6 and disabled otherwise.
+
+@item -mfused-madd
+@itemx -mno-fused-madd
+@opindex mfused-madd
+@opindex mno-fused-madd
+Generate code that uses (does not use) the floating-point multiply and
+accumulate instructions.  These instructions are generated by default
+if hardware floating point is used.  The machine-dependent
+@option{-mfused-madd} option is now mapped to the machine-independent
+@option{-ffp-contract=fast} option, and @option{-mno-fused-madd} is
+mapped to @option{-ffp-contract=off}.
+
+@item -mmulhw
+@itemx -mno-mulhw
+@opindex mmulhw
+@opindex mno-mulhw
+Generate code that uses (does not use) the half-word multiply and
+multiply-accumulate instructions on the IBM 405, 440, 464 and 476 processors.
+These instructions are generated by default when targeting those
+processors.
+
+@item -mdlmzb
+@itemx -mno-dlmzb
+@opindex mdlmzb
+@opindex mno-dlmzb
+Generate code that uses (does not use) the string-search @samp{dlmzb}
+instruction on the IBM 405, 440, 464 and 476 processors.  This instruction is
+generated by default when targeting those processors.
+
+@item -mno-bit-align
+@itemx -mbit-align
+@opindex mno-bit-align
+@opindex mbit-align
+On System V.4 and embedded PowerPC systems do not (do) force structures
+and unions that contain bit-fields to be aligned to the base type of the
+bit-field.
+
+For example, by default a structure containing nothing but 8
+@code{unsigned} bit-fields of length 1 is aligned to a 4-byte
+boundary and has a size of 4 bytes.  By using @option{-mno-bit-align},
+the structure is aligned to a 1-byte boundary and is 1 byte in
+size.
+
+@item -mno-strict-align
+@itemx -mstrict-align
+@opindex mno-strict-align
+@opindex mstrict-align
+On System V.4 and embedded PowerPC systems do not (do) assume that
+unaligned memory references are handled by the system.
+
+@item -mrelocatable
+@itemx -mno-relocatable
+@opindex mrelocatable
+@opindex mno-relocatable
+Generate code that allows (does not allow) a static executable to be
+relocated to a different address at run time.  A simple embedded
+PowerPC system loader should relocate the entire contents of
+@code{.got2} and 4-byte locations listed in the @code{.fixup} section,
+a table of 32-bit addresses generated by this option.  For this to
+work, all objects linked together must be compiled with
+@option{-mrelocatable} or @option{-mrelocatable-lib}.
+@option{-mrelocatable} code aligns the stack to an 8-byte boundary.
+
+@item -mrelocatable-lib
+@itemx -mno-relocatable-lib
+@opindex mrelocatable-lib
+@opindex mno-relocatable-lib
+Like @option{-mrelocatable}, @option{-mrelocatable-lib} generates a
+@code{.fixup} section to allow static executables to be relocated at
+run time, but @option{-mrelocatable-lib} does not use the smaller stack
+alignment of @option{-mrelocatable}.  Objects compiled with
+@option{-mrelocatable-lib} may be linked with objects compiled with
+any combination of the @option{-mrelocatable} options.
+
+@item -mno-toc
+@itemx -mtoc
+@opindex mno-toc
+@opindex mtoc
+On System V.4 and embedded PowerPC systems do not (do) assume that
+register 2 contains a pointer to a global area pointing to the addresses
+used in the program.
+
+@item -mlittle
+@itemx -mlittle-endian
+@opindex mlittle
+@opindex mlittle-endian
+On System V.4 and embedded PowerPC systems compile code for the
+processor in little-endian mode.  The @option{-mlittle-endian} option is
+the same as @option{-mlittle}.
+
+@item -mbig
+@itemx -mbig-endian
+@opindex mbig
+@opindex mbig-endian
+On System V.4 and embedded PowerPC systems compile code for the
+processor in big-endian mode.  The @option{-mbig-endian} option is
+the same as @option{-mbig}.
+
+@item -mdynamic-no-pic
+@opindex mdynamic-no-pic
+On Darwin and Mac OS X systems, compile code so that it is not
+relocatable, but that its external references are relocatable.  The
+resulting code is suitable for applications, but not shared
+libraries.
+
+@item -msingle-pic-base
+@opindex msingle-pic-base
+Treat the register used for PIC addressing as read-only, rather than
+loading it in the prologue for each function.  The runtime system is
+responsible for initializing this register with an appropriate value
+before execution begins.
+
+@item -mprioritize-restricted-insns=@var{priority}
+@opindex mprioritize-restricted-insns
+This option controls the priority that is assigned to
+dispatch-slot restricted instructions during the second scheduling
+pass.  The argument @var{priority} takes the value @samp{0}, @samp{1},
+or @samp{2} to assign no, highest, or second-highest (respectively) 
+priority to dispatch-slot restricted
+instructions.
+
+@item -msched-costly-dep=@var{dependence_type}
+@opindex msched-costly-dep
+This option controls which dependences are considered costly
+by the target during instruction scheduling.  The argument
+@var{dependence_type} takes one of the following values:
+
+@table @asis
+@item @samp{no}
+No dependence is costly.
+
+@item @samp{all}
+All dependences are costly.
+
+@item @samp{true_store_to_load}
+A true dependence from store to load is costly.
+
+@item @samp{store_to_load}
+Any dependence from store to load is costly.
+
+@item @var{number}
+Any dependence for which the latency is greater than or equal to 
+@var{number} is costly.
+@end table
+
+@item -minsert-sched-nops=@var{scheme}
+@opindex minsert-sched-nops
+This option controls which NOP insertion scheme is used during
+the second scheduling pass.  The argument @var{scheme} takes one of the
+following values:
+
+@table @asis
+@item @samp{no}
+Don't insert NOPs.
+
+@item @samp{pad}
+Pad with NOPs any dispatch group that has vacant issue slots,
+according to the scheduler's grouping.
+
+@item @samp{regroup_exact}
+Insert NOPs to force costly dependent insns into
+separate groups.  Insert exactly as many NOPs as needed to force an insn
+to a new group, according to the estimated processor grouping.
+
+@item @var{number}
+Insert NOPs to force costly dependent insns into
+separate groups.  Insert @var{number} NOPs to force an insn to a new group.
+@end table
+
+@item -mcall-sysv
+@opindex mcall-sysv
+On System V.4 and embedded PowerPC systems compile code using calling
+conventions that adhere to the March 1995 draft of the System V
+Application Binary Interface, PowerPC processor supplement.  This is the
+default unless you configured GCC using @samp{powerpc-*-eabiaix}.
+
+@item -mcall-sysv-eabi
+@itemx -mcall-eabi
+@opindex mcall-sysv-eabi
+@opindex mcall-eabi
+Specify both @option{-mcall-sysv} and @option{-meabi} options.
+
+@item -mcall-sysv-noeabi
+@opindex mcall-sysv-noeabi
+Specify both @option{-mcall-sysv} and @option{-mno-eabi} options.
+
+@item -mcall-aixdesc
+@opindex m
+On System V.4 and embedded PowerPC systems compile code for the AIX
+operating system.
+
+@item -mcall-linux
+@opindex mcall-linux
+On System V.4 and embedded PowerPC systems compile code for the
+Linux-based GNU system.
+
+@item -mcall-freebsd
+@opindex mcall-freebsd
+On System V.4 and embedded PowerPC systems compile code for the
+FreeBSD operating system.
+
+@item -mcall-netbsd
+@opindex mcall-netbsd
+On System V.4 and embedded PowerPC systems compile code for the
+NetBSD operating system.
+
+@item -mcall-openbsd
+@opindex mcall-netbsd
+On System V.4 and embedded PowerPC systems compile code for the
+OpenBSD operating system.
+
+@item -maix-struct-return
+@opindex maix-struct-return
+Return all structures in memory (as specified by the AIX ABI)@.
+
+@item -msvr4-struct-return
+@opindex msvr4-struct-return
+Return structures smaller than 8 bytes in registers (as specified by the
+SVR4 ABI)@.
+
+@item -mabi=@var{abi-type}
+@opindex mabi
+Extend the current ABI with a particular extension, or remove such extension.
+Valid values are @var{altivec}, @var{no-altivec}, @var{spe},
+@var{no-spe}, @var{ibmlongdouble}, @var{ieeelongdouble},
+@var{elfv1}, @var{elfv2}@.
+
+@item -mabi=spe
+@opindex mabi=spe
+Extend the current ABI with SPE ABI extensions.  This does not change
+the default ABI, instead it adds the SPE ABI extensions to the current
+ABI@.
+
+@item -mabi=no-spe
+@opindex mabi=no-spe
+Disable Book-E SPE ABI extensions for the current ABI@.
+
+@item -mabi=ibmlongdouble
+@opindex mabi=ibmlongdouble
+Change the current ABI to use IBM extended-precision long double.
+This is a PowerPC 32-bit SYSV ABI option.
+
+@item -mabi=ieeelongdouble
+@opindex mabi=ieeelongdouble
+Change the current ABI to use IEEE extended-precision long double.
+This is a PowerPC 32-bit Linux ABI option.
+
+@item -mabi=elfv1
+@opindex mabi=elfv1
+Change the current ABI to use the ELFv1 ABI.
+This is the default ABI for big-endian PowerPC 64-bit Linux.
+Overriding the default ABI requires special system support and is
+likely to fail in spectacular ways.
+
+@item -mabi=elfv2
+@opindex mabi=elfv2
+Change the current ABI to use the ELFv2 ABI.
+This is the default ABI for little-endian PowerPC 64-bit Linux.
+Overriding the default ABI requires special system support and is
+likely to fail in spectacular ways.
+
+@item -mprototype
+@itemx -mno-prototype
+@opindex mprototype
+@opindex mno-prototype
+On System V.4 and embedded PowerPC systems assume that all calls to
+variable argument functions are properly prototyped.  Otherwise, the
+compiler must insert an instruction before every non-prototyped call to
+set or clear bit 6 of the condition code register (@var{CR}) to
+indicate whether floating-point values are passed in the floating-point
+registers in case the function takes variable arguments.  With
+@option{-mprototype}, only calls to prototyped variable argument functions
+set or clear the bit.
+
+@item -msim
+@opindex msim
+On embedded PowerPC systems, assume that the startup module is called
+@file{sim-crt0.o} and that the standard C libraries are @file{libsim.a} and
+@file{libc.a}.  This is the default for @samp{powerpc-*-eabisim}
+configurations.
+
+@item -mmvme
+@opindex mmvme
+On embedded PowerPC systems, assume that the startup module is called
+@file{crt0.o} and the standard C libraries are @file{libmvme.a} and
+@file{libc.a}.
+
+@item -mads
+@opindex mads
+On embedded PowerPC systems, assume that the startup module is called
+@file{crt0.o} and the standard C libraries are @file{libads.a} and
+@file{libc.a}.
+
+@item -myellowknife
+@opindex myellowknife
+On embedded PowerPC systems, assume that the startup module is called
+@file{crt0.o} and the standard C libraries are @file{libyk.a} and
+@file{libc.a}.
+
+@item -mvxworks
+@opindex mvxworks
+On System V.4 and embedded PowerPC systems, specify that you are
+compiling for a VxWorks system.
+
+@item -memb
+@opindex memb
+On embedded PowerPC systems, set the @var{PPC_EMB} bit in the ELF flags
+header to indicate that @samp{eabi} extended relocations are used.
+
+@item -meabi
+@itemx -mno-eabi
+@opindex meabi
+@opindex mno-eabi
+On System V.4 and embedded PowerPC systems do (do not) adhere to the
+Embedded Applications Binary Interface (EABI), which is a set of
+modifications to the System V.4 specifications.  Selecting @option{-meabi}
+means that the stack is aligned to an 8-byte boundary, a function
+@code{__eabi} is called from @code{main} to set up the EABI
+environment, and the @option{-msdata} option can use both @code{r2} and
+@code{r13} to point to two separate small data areas.  Selecting
+@option{-mno-eabi} means that the stack is aligned to a 16-byte boundary,
+no EABI initialization function is called from @code{main}, and the
+@option{-msdata} option only uses @code{r13} to point to a single
+small data area.  The @option{-meabi} option is on by default if you
+configured GCC using one of the @samp{powerpc*-*-eabi*} options.
+
+@item -msdata=eabi
+@opindex msdata=eabi
+On System V.4 and embedded PowerPC systems, put small initialized
+@code{const} global and static data in the @samp{.sdata2} section, which
+is pointed to by register @code{r2}.  Put small initialized
+non-@code{const} global and static data in the @samp{.sdata} section,
+which is pointed to by register @code{r13}.  Put small uninitialized
+global and static data in the @samp{.sbss} section, which is adjacent to
+the @samp{.sdata} section.  The @option{-msdata=eabi} option is
+incompatible with the @option{-mrelocatable} option.  The
+@option{-msdata=eabi} option also sets the @option{-memb} option.
+
+@item -msdata=sysv
+@opindex msdata=sysv
+On System V.4 and embedded PowerPC systems, put small global and static
+data in the @samp{.sdata} section, which is pointed to by register
+@code{r13}.  Put small uninitialized global and static data in the
+@samp{.sbss} section, which is adjacent to the @samp{.sdata} section.
+The @option{-msdata=sysv} option is incompatible with the
+@option{-mrelocatable} option.
+
+@item -msdata=default
+@itemx -msdata
+@opindex msdata=default
+@opindex msdata
+On System V.4 and embedded PowerPC systems, if @option{-meabi} is used,
+compile code the same as @option{-msdata=eabi}, otherwise compile code the
+same as @option{-msdata=sysv}.
+
+@item -msdata=data
+@opindex msdata=data
+On System V.4 and embedded PowerPC systems, put small global
+data in the @samp{.sdata} section.  Put small uninitialized global
+data in the @samp{.sbss} section.  Do not use register @code{r13}
+to address small data however.  This is the default behavior unless
+other @option{-msdata} options are used.
+
+@item -msdata=none
+@itemx -mno-sdata
+@opindex msdata=none
+@opindex mno-sdata
+On embedded PowerPC systems, put all initialized global and static data
+in the @samp{.data} section, and all uninitialized data in the
+@samp{.bss} section.
+
+@item -mblock-move-inline-limit=@var{num}
+@opindex mblock-move-inline-limit
+Inline all block moves (such as calls to @code{memcpy} or structure
+copies) less than or equal to @var{num} bytes.  The minimum value for
+@var{num} is 32 bytes on 32-bit targets and 64 bytes on 64-bit
+targets.  The default value is target-specific.
+
+@item -G @var{num}
+@opindex G
+@cindex smaller data references (PowerPC)
+@cindex .sdata/.sdata2 references (PowerPC)
+On embedded PowerPC systems, put global and static items less than or
+equal to @var{num} bytes into the small data or BSS sections instead of
+the normal data or BSS section.  By default, @var{num} is 8.  The
+@option{-G @var{num}} switch is also passed to the linker.
+All modules should be compiled with the same @option{-G @var{num}} value.
+
+@item -mregnames
+@itemx -mno-regnames
+@opindex mregnames
+@opindex mno-regnames
+On System V.4 and embedded PowerPC systems do (do not) emit register
+names in the assembly language output using symbolic forms.
+
+@item -mlongcall
+@itemx -mno-longcall
+@opindex mlongcall
+@opindex mno-longcall
+By default assume that all calls are far away so that a longer and more
+expensive calling sequence is required.  This is required for calls
+farther than 32 megabytes (33,554,432 bytes) from the current location.
+A short call is generated if the compiler knows
+the call cannot be that far away.  This setting can be overridden by
+the @code{shortcall} function attribute, or by @code{#pragma
+longcall(0)}.
+
+Some linkers are capable of detecting out-of-range calls and generating
+glue code on the fly.  On these systems, long calls are unnecessary and
+generate slower code.  As of this writing, the AIX linker can do this,
+as can the GNU linker for PowerPC/64.  It is planned to add this feature
+to the GNU linker for 32-bit PowerPC systems as well.
+
+On Darwin/PPC systems, @code{#pragma longcall} generates @code{jbsr
+callee, L42}, plus a @dfn{branch island} (glue code).  The two target
+addresses represent the callee and the branch island.  The
+Darwin/PPC linker prefers the first address and generates a @code{bl
+callee} if the PPC @code{bl} instruction reaches the callee directly;
+otherwise, the linker generates @code{bl L42} to call the branch
+island.  The branch island is appended to the body of the
+calling function; it computes the full 32-bit address of the callee
+and jumps to it.
+
+On Mach-O (Darwin) systems, this option directs the compiler emit to
+the glue for every direct call, and the Darwin linker decides whether
+to use or discard it.
+
+In the future, GCC may ignore all longcall specifications
+when the linker is known to generate glue.
+
+@item -mtls-markers
+@itemx -mno-tls-markers
+@opindex mtls-markers
+@opindex mno-tls-markers
+Mark (do not mark) calls to @code{__tls_get_addr} with a relocation
+specifying the function argument.  The relocation allows the linker to
+reliably associate function call with argument setup instructions for
+TLS optimization, which in turn allows GCC to better schedule the
+sequence.
+
+@item -pthread
+@opindex pthread
+Adds support for multithreading with the @dfn{pthreads} library.
+This option sets flags for both the preprocessor and linker.
+
+@item -mrecip
+@itemx -mno-recip
+@opindex mrecip
+This option enables use of the reciprocal estimate and
+reciprocal square root estimate instructions with additional
+Newton-Raphson steps to increase precision instead of doing a divide or
+square root and divide for floating-point arguments.  You should use
+the @option{-ffast-math} option when using @option{-mrecip} (or at
+least @option{-funsafe-math-optimizations},
+@option{-finite-math-only}, @option{-freciprocal-math} and
+@option{-fno-trapping-math}).  Note that while the throughput of the
+sequence is generally higher than the throughput of the non-reciprocal
+instruction, the precision of the sequence can be decreased by up to 2
+ulp (i.e.@: the inverse of 1.0 equals 0.99999994) for reciprocal square
+roots.
+
+@item -mrecip=@var{opt}
+@opindex mrecip=opt
+This option controls which reciprocal estimate instructions
+may be used.  @var{opt} is a comma-separated list of options, which may
+be preceded by a @code{!} to invert the option:
+@code{all}: enable all estimate instructions,
+@code{default}: enable the default instructions, equivalent to @option{-mrecip},
+@code{none}: disable all estimate instructions, equivalent to @option{-mno-recip};
+@code{div}: enable the reciprocal approximation instructions for both single and double precision;
+@code{divf}: enable the single-precision reciprocal approximation instructions;
+@code{divd}: enable the double-precision reciprocal approximation instructions;
+@code{rsqrt}: enable the reciprocal square root approximation instructions for both single and double precision;
+@code{rsqrtf}: enable the single-precision reciprocal square root approximation instructions;
+@code{rsqrtd}: enable the double-precision reciprocal square root approximation instructions;
+
+So, for example, @option{-mrecip=all,!rsqrtd} enables
+all of the reciprocal estimate instructions, except for the
+@code{FRSQRTE}, @code{XSRSQRTEDP}, and @code{XVRSQRTEDP} instructions
+which handle the double-precision reciprocal square root calculations.
+
+@item -mrecip-precision
+@itemx -mno-recip-precision
+@opindex mrecip-precision
+Assume (do not assume) that the reciprocal estimate instructions
+provide higher-precision estimates than is mandated by the PowerPC
+ABI.  Selecting @option{-mcpu=power6}, @option{-mcpu=power7} or
+@option{-mcpu=power8} automatically selects @option{-mrecip-precision}.
+The double-precision square root estimate instructions are not generated by
+default on low-precision machines, since they do not provide an
+estimate that converges after three steps.
+
+@item -mveclibabi=@var{type}
+@opindex mveclibabi
+Specifies the ABI type to use for vectorizing intrinsics using an
+external library.  The only type supported at present is @code{mass},
+which specifies to use IBM's Mathematical Acceleration Subsystem
+(MASS) libraries for vectorizing intrinsics using external libraries.
+GCC currently emits calls to @code{acosd2}, @code{acosf4},
+@code{acoshd2}, @code{acoshf4}, @code{asind2}, @code{asinf4},
+@code{asinhd2}, @code{asinhf4}, @code{atan2d2}, @code{atan2f4},
+@code{atand2}, @code{atanf4}, @code{atanhd2}, @code{atanhf4},
+@code{cbrtd2}, @code{cbrtf4}, @code{cosd2}, @code{cosf4},
+@code{coshd2}, @code{coshf4}, @code{erfcd2}, @code{erfcf4},
+@code{erfd2}, @code{erff4}, @code{exp2d2}, @code{exp2f4},
+@code{expd2}, @code{expf4}, @code{expm1d2}, @code{expm1f4},
+@code{hypotd2}, @code{hypotf4}, @code{lgammad2}, @code{lgammaf4},
+@code{log10d2}, @code{log10f4}, @code{log1pd2}, @code{log1pf4},
+@code{log2d2}, @code{log2f4}, @code{logd2}, @code{logf4},
+@code{powd2}, @code{powf4}, @code{sind2}, @code{sinf4}, @code{sinhd2},
+@code{sinhf4}, @code{sqrtd2}, @code{sqrtf4}, @code{tand2},
+@code{tanf4}, @code{tanhd2}, and @code{tanhf4} when generating code
+for power7.  Both @option{-ftree-vectorize} and
+@option{-funsafe-math-optimizations} must also be enabled.  The MASS
+libraries must be specified at link time.
+
+@item -mfriz
+@itemx -mno-friz
+@opindex mfriz
+Generate (do not generate) the @code{friz} instruction when the
+@option{-funsafe-math-optimizations} option is used to optimize
+rounding of floating-point values to 64-bit integer and back to floating
+point.  The @code{friz} instruction does not return the same value if
+the floating-point number is too large to fit in an integer.
+
+@item -mpointers-to-nested-functions
+@itemx -mno-pointers-to-nested-functions
+@opindex mpointers-to-nested-functions
+Generate (do not generate) code to load up the static chain register
+(@var{r11}) when calling through a pointer on AIX and 64-bit Linux
+systems where a function pointer points to a 3-word descriptor giving
+the function address, TOC value to be loaded in register @var{r2}, and
+static chain value to be loaded in register @var{r11}.  The
+@option{-mpointers-to-nested-functions} is on by default.  You cannot
+call through pointers to nested functions or pointers
+to functions compiled in other languages that use the static chain if
+you use the @option{-mno-pointers-to-nested-functions}.
+
+@item -msave-toc-indirect
+@itemx -mno-save-toc-indirect
+@opindex msave-toc-indirect
+Generate (do not generate) code to save the TOC value in the reserved
+stack location in the function prologue if the function calls through
+a pointer on AIX and 64-bit Linux systems.  If the TOC value is not
+saved in the prologue, it is saved just before the call through the
+pointer.  The @option{-mno-save-toc-indirect} option is the default.
+
+@item -mcompat-align-parm
+@itemx -mno-compat-align-parm
+@opindex mcompat-align-parm
+Generate (do not generate) code to pass structure parameters with a
+maximum alignment of 64 bits, for compatibility with older versions
+of GCC.
+
+Older versions of GCC (prior to 4.9.0) incorrectly did not align a
+structure parameter on a 128-bit boundary when that structure contained
+a member requiring 128-bit alignment.  This is corrected in more
+recent versions of GCC.  This option may be used to generate code
+that is compatible with functions compiled with older versions of
+GCC.
+
+In this version of the compiler, the @option{-mcompat-align-parm}
+is the default, except when using the Linux ELFv2 ABI.
+@end table
+
+@node RX Options
+@subsection RX Options
+@cindex RX Options
+
+These command-line options are defined for RX targets:
+
+@table @gcctabopt
+@item -m64bit-doubles
+@itemx -m32bit-doubles
+@opindex m64bit-doubles
+@opindex m32bit-doubles
+Make the @code{double} data type be 64 bits (@option{-m64bit-doubles})
+or 32 bits (@option{-m32bit-doubles}) in size.  The default is
+@option{-m32bit-doubles}.  @emph{Note} RX floating-point hardware only
+works on 32-bit values, which is why the default is
+@option{-m32bit-doubles}.
+
+@item -fpu
+@itemx -nofpu
+@opindex fpu
+@opindex nofpu
+Enables (@option{-fpu}) or disables (@option{-nofpu}) the use of RX
+floating-point hardware.  The default is enabled for the @var{RX600}
+series and disabled for the @var{RX200} series.
+
+Floating-point instructions are only generated for 32-bit floating-point 
+values, however, so the FPU hardware is not used for doubles if the
+@option{-m64bit-doubles} option is used.
+
+@emph{Note} If the @option{-fpu} option is enabled then
+@option{-funsafe-math-optimizations} is also enabled automatically.
+This is because the RX FPU instructions are themselves unsafe.
+
+@item -mcpu=@var{name}
+@opindex -mcpu
+Selects the type of RX CPU to be targeted.  Currently three types are
+supported, the generic @var{RX600} and @var{RX200} series hardware and
+the specific @var{RX610} CPU.  The default is @var{RX600}.
+
+The only difference between @var{RX600} and @var{RX610} is that the
+@var{RX610} does not support the @code{MVTIPL} instruction.
+
+The @var{RX200} series does not have a hardware floating-point unit
+and so @option{-nofpu} is enabled by default when this type is
+selected.
+
+@item -mbig-endian-data
+@itemx -mlittle-endian-data
+@opindex mbig-endian-data
+@opindex mlittle-endian-data
+Store data (but not code) in the big-endian format.  The default is
+@option{-mlittle-endian-data}, i.e.@: to store data in the little-endian
+format.
+
+@item -msmall-data-limit=@var{N}
+@opindex msmall-data-limit
+Specifies the maximum size in bytes of global and static variables
+which can be placed into the small data area.  Using the small data
+area can lead to smaller and faster code, but the size of area is
+limited and it is up to the programmer to ensure that the area does
+not overflow.  Also when the small data area is used one of the RX's
+registers (usually @code{r13}) is reserved for use pointing to this
+area, so it is no longer available for use by the compiler.  This
+could result in slower and/or larger code if variables are pushed onto
+the stack instead of being held in this register.
+
+Note, common variables (variables that have not been initialized) and
+constants are not placed into the small data area as they are assigned
+to other sections in the output executable.
+
+The default value is zero, which disables this feature.  Note, this
+feature is not enabled by default with higher optimization levels
+(@option{-O2} etc) because of the potentially detrimental effects of
+reserving a register.  It is up to the programmer to experiment and
+discover whether this feature is of benefit to their program.  See the
+description of the @option{-mpid} option for a description of how the
+actual register to hold the small data area pointer is chosen.
+
+@item -msim
+@itemx -mno-sim
+@opindex msim
+@opindex mno-sim
+Use the simulator runtime.  The default is to use the libgloss
+board-specific runtime.
+
+@item -mas100-syntax
+@itemx -mno-as100-syntax
+@opindex mas100-syntax
+@opindex mno-as100-syntax
+When generating assembler output use a syntax that is compatible with
+Renesas's AS100 assembler.  This syntax can also be handled by the GAS
+assembler, but it has some restrictions so it is not generated by default.
+
+@item -mmax-constant-size=@var{N}
+@opindex mmax-constant-size
+Specifies the maximum size, in bytes, of a constant that can be used as
+an operand in a RX instruction.  Although the RX instruction set does
+allow constants of up to 4 bytes in length to be used in instructions,
+a longer value equates to a longer instruction.  Thus in some
+circumstances it can be beneficial to restrict the size of constants
+that are used in instructions.  Constants that are too big are instead
+placed into a constant pool and referenced via register indirection.
+
+The value @var{N} can be between 0 and 4.  A value of 0 (the default)
+or 4 means that constants of any size are allowed.
+
+@item -mrelax
+@opindex mrelax
+Enable linker relaxation.  Linker relaxation is a process whereby the
+linker attempts to reduce the size of a program by finding shorter
+versions of various instructions.  Disabled by default.
+
+@item -mint-register=@var{N}
+@opindex mint-register
+Specify the number of registers to reserve for fast interrupt handler
+functions.  The value @var{N} can be between 0 and 4.  A value of 1
+means that register @code{r13} is reserved for the exclusive use
+of fast interrupt handlers.  A value of 2 reserves @code{r13} and
+@code{r12}.  A value of 3 reserves @code{r13}, @code{r12} and
+@code{r11}, and a value of 4 reserves @code{r13} through @code{r10}.
+A value of 0, the default, does not reserve any registers.
+
+@item -msave-acc-in-interrupts
+@opindex msave-acc-in-interrupts
+Specifies that interrupt handler functions should preserve the
+accumulator register.  This is only necessary if normal code might use
+the accumulator register, for example because it performs 64-bit
+multiplications.  The default is to ignore the accumulator as this
+makes the interrupt handlers faster.
+
+@item -mpid
+@itemx -mno-pid
+@opindex mpid
+@opindex mno-pid
+Enables the generation of position independent data.  When enabled any
+access to constant data is done via an offset from a base address
+held in a register.  This allows the location of constant data to be
+determined at run time without requiring the executable to be
+relocated, which is a benefit to embedded applications with tight
+memory constraints.  Data that can be modified is not affected by this
+option.
+
+Note, using this feature reserves a register, usually @code{r13}, for
+the constant data base address.  This can result in slower and/or
+larger code, especially in complicated functions.
+
+The actual register chosen to hold the constant data base address
+depends upon whether the @option{-msmall-data-limit} and/or the
+@option{-mint-register} command-line options are enabled.  Starting
+with register @code{r13} and proceeding downwards, registers are
+allocated first to satisfy the requirements of @option{-mint-register},
+then @option{-mpid} and finally @option{-msmall-data-limit}.  Thus it
+is possible for the small data area register to be @code{r8} if both
+@option{-mint-register=4} and @option{-mpid} are specified on the
+command line.
+
+By default this feature is not enabled.  The default can be restored
+via the @option{-mno-pid} command-line option.
+
+@item -mno-warn-multiple-fast-interrupts
+@itemx -mwarn-multiple-fast-interrupts
+@opindex mno-warn-multiple-fast-interrupts
+@opindex mwarn-multiple-fast-interrupts
+Prevents GCC from issuing a warning message if it finds more than one
+fast interrupt handler when it is compiling a file.  The default is to
+issue a warning for each extra fast interrupt handler found, as the RX
+only supports one such interrupt.
+
+@end table
+
+@emph{Note:} The generic GCC command-line option @option{-ffixed-@var{reg}}
+has special significance to the RX port when used with the
+@code{interrupt} function attribute.  This attribute indicates a
+function intended to process fast interrupts.  GCC ensures
+that it only uses the registers @code{r10}, @code{r11}, @code{r12}
+and/or @code{r13} and only provided that the normal use of the
+corresponding registers have been restricted via the
+@option{-ffixed-@var{reg}} or @option{-mint-register} command-line
+options.
+
+@node S/390 and zSeries Options
+@subsection S/390 and zSeries Options
+@cindex S/390 and zSeries Options
+
+These are the @samp{-m} options defined for the S/390 and zSeries architecture.
+
+@table @gcctabopt
+@item -mhard-float
+@itemx -msoft-float
+@opindex mhard-float
+@opindex msoft-float
+Use (do not use) the hardware floating-point instructions and registers
+for floating-point operations.  When @option{-msoft-float} is specified,
+functions in @file{libgcc.a} are used to perform floating-point
+operations.  When @option{-mhard-float} is specified, the compiler
+generates IEEE floating-point instructions.  This is the default.
+
+@item -mhard-dfp
+@itemx -mno-hard-dfp
+@opindex mhard-dfp
+@opindex mno-hard-dfp
+Use (do not use) the hardware decimal-floating-point instructions for
+decimal-floating-point operations.  When @option{-mno-hard-dfp} is
+specified, functions in @file{libgcc.a} are used to perform
+decimal-floating-point operations.  When @option{-mhard-dfp} is
+specified, the compiler generates decimal-floating-point hardware
+instructions.  This is the default for @option{-march=z9-ec} or higher.
+
+@item -mlong-double-64
+@itemx -mlong-double-128
+@opindex mlong-double-64
+@opindex mlong-double-128
+These switches control the size of @code{long double} type. A size
+of 64 bits makes the @code{long double} type equivalent to the @code{double}
+type. This is the default.
+
+@item -mbackchain
+@itemx -mno-backchain
+@opindex mbackchain
+@opindex mno-backchain
+Store (do not store) the address of the caller's frame as backchain pointer
+into the callee's stack frame.
+A backchain may be needed to allow debugging using tools that do not understand
+DWARF 2 call frame information.
+When @option{-mno-packed-stack} is in effect, the backchain pointer is stored
+at the bottom of the stack frame; when @option{-mpacked-stack} is in effect,
+the backchain is placed into the topmost word of the 96/160 byte register
+save area.
+
+In general, code compiled with @option{-mbackchain} is call-compatible with
+code compiled with @option{-mmo-backchain}; however, use of the backchain
+for debugging purposes usually requires that the whole binary is built with
+@option{-mbackchain}.  Note that the combination of @option{-mbackchain},
+@option{-mpacked-stack} and @option{-mhard-float} is not supported.  In order
+to build a linux kernel use @option{-msoft-float}.
+
+The default is to not maintain the backchain.
+
+@item -mpacked-stack
+@itemx -mno-packed-stack
+@opindex mpacked-stack
+@opindex mno-packed-stack
+Use (do not use) the packed stack layout.  When @option{-mno-packed-stack} is
+specified, the compiler uses the all fields of the 96/160 byte register save
+area only for their default purpose; unused fields still take up stack space.
+When @option{-mpacked-stack} is specified, register save slots are densely
+packed at the top of the register save area; unused space is reused for other
+purposes, allowing for more efficient use of the available stack space.
+However, when @option{-mbackchain} is also in effect, the topmost word of
+the save area is always used to store the backchain, and the return address
+register is always saved two words below the backchain.
+
+As long as the stack frame backchain is not used, code generated with
+@option{-mpacked-stack} is call-compatible with code generated with
+@option{-mno-packed-stack}.  Note that some non-FSF releases of GCC 2.95 for
+S/390 or zSeries generated code that uses the stack frame backchain at run
+time, not just for debugging purposes.  Such code is not call-compatible
+with code compiled with @option{-mpacked-stack}.  Also, note that the
+combination of @option{-mbackchain},
+@option{-mpacked-stack} and @option{-mhard-float} is not supported.  In order
+to build a linux kernel use @option{-msoft-float}.
+
+The default is to not use the packed stack layout.
+
+@item -msmall-exec
+@itemx -mno-small-exec
+@opindex msmall-exec
+@opindex mno-small-exec
+Generate (or do not generate) code using the @code{bras} instruction
+to do subroutine calls.
+This only works reliably if the total executable size does not
+exceed 64k.  The default is to use the @code{basr} instruction instead,
+which does not have this limitation.
+
+@item -m64
+@itemx -m31
+@opindex m64
+@opindex m31
+When @option{-m31} is specified, generate code compliant to the
+GNU/Linux for S/390 ABI@.  When @option{-m64} is specified, generate
+code compliant to the GNU/Linux for zSeries ABI@.  This allows GCC in
+particular to generate 64-bit instructions.  For the @samp{s390}
+targets, the default is @option{-m31}, while the @samp{s390x}
+targets default to @option{-m64}.
+
+@item -mzarch
+@itemx -mesa
+@opindex mzarch
+@opindex mesa
+When @option{-mzarch} is specified, generate code using the
+instructions available on z/Architecture.
+When @option{-mesa} is specified, generate code using the
+instructions available on ESA/390.  Note that @option{-mesa} is
+not possible with @option{-m64}.
+When generating code compliant to the GNU/Linux for S/390 ABI,
+the default is @option{-mesa}.  When generating code compliant
+to the GNU/Linux for zSeries ABI, the default is @option{-mzarch}.
+
+@item -mmvcle
+@itemx -mno-mvcle
+@opindex mmvcle
+@opindex mno-mvcle
+Generate (or do not generate) code using the @code{mvcle} instruction
+to perform block moves.  When @option{-mno-mvcle} is specified,
+use a @code{mvc} loop instead.  This is the default unless optimizing for
+size.
+
+@item -mdebug
+@itemx -mno-debug
+@opindex mdebug
+@opindex mno-debug
+Print (or do not print) additional debug information when compiling.
+The default is to not print debug information.
+
+@item -march=@var{cpu-type}
+@opindex march
+Generate code that runs on @var{cpu-type}, which is the name of a system
+representing a certain processor type.  Possible values for
+@var{cpu-type} are @samp{g5}, @samp{g6}, @samp{z900}, @samp{z990},
+@samp{z9-109}, @samp{z9-ec} and @samp{z10}.
+When generating code using the instructions available on z/Architecture,
+the default is @option{-march=z900}.  Otherwise, the default is
+@option{-march=g5}.
+
+@item -mtune=@var{cpu-type}
+@opindex mtune
+Tune to @var{cpu-type} everything applicable about the generated code,
+except for the ABI and the set of available instructions.
+The list of @var{cpu-type} values is the same as for @option{-march}.
+The default is the value used for @option{-march}.
+
+@item -mtpf-trace
+@itemx -mno-tpf-trace
+@opindex mtpf-trace
+@opindex mno-tpf-trace
+Generate code that adds (does not add) in TPF OS specific branches to trace
+routines in the operating system.  This option is off by default, even
+when compiling for the TPF OS@.
+
+@item -mfused-madd
+@itemx -mno-fused-madd
+@opindex mfused-madd
+@opindex mno-fused-madd
+Generate code that uses (does not use) the floating-point multiply and
+accumulate instructions.  These instructions are generated by default if
+hardware floating point is used.
+
+@item -mwarn-framesize=@var{framesize}
+@opindex mwarn-framesize
+Emit a warning if the current function exceeds the given frame size.  Because
+this is a compile-time check it doesn't need to be a real problem when the program
+runs.  It is intended to identify functions that most probably cause
+a stack overflow.  It is useful to be used in an environment with limited stack
+size e.g.@: the linux kernel.
+
+@item -mwarn-dynamicstack
+@opindex mwarn-dynamicstack
+Emit a warning if the function calls @code{alloca} or uses dynamically-sized
+arrays.  This is generally a bad idea with a limited stack size.
+
+@item -mstack-guard=@var{stack-guard}
+@itemx -mstack-size=@var{stack-size}
+@opindex mstack-guard
+@opindex mstack-size
+If these options are provided the S/390 back end emits additional instructions in
+the function prologue that trigger a trap if the stack size is @var{stack-guard}
+bytes above the @var{stack-size} (remember that the stack on S/390 grows downward).
+If the @var{stack-guard} option is omitted the smallest power of 2 larger than
+the frame size of the compiled function is chosen.
+These options are intended to be used to help debugging stack overflow problems.
+The additionally emitted code causes only little overhead and hence can also be
+used in production-like systems without greater performance degradation.  The given
+values have to be exact powers of 2 and @var{stack-size} has to be greater than
+@var{stack-guard} without exceeding 64k.
+In order to be efficient the extra code makes the assumption that the stack starts
+at an address aligned to the value given by @var{stack-size}.
+The @var{stack-guard} option can only be used in conjunction with @var{stack-size}.
+
+@item -mhotpatch[=@var{halfwords}]
+@itemx -mno-hotpatch
+@opindex mhotpatch
+If the hotpatch option is enabled, a ``hot-patching'' function
+prologue is generated for all functions in the compilation unit.
+The funtion label is prepended with the given number of two-byte
+Nop instructions (@var{halfwords}, maximum 1000000) or 12 Nop
+instructions if no argument is present.  Functions with a
+hot-patching prologue are never inlined automatically, and a
+hot-patching prologue is never generated for functions functions
+that are explicitly inline.
+
+This option can be overridden for individual functions with the
+@code{hotpatch} attribute.
+@end table
+
+@node Score Options
+@subsection Score Options
+@cindex Score Options
+
+These options are defined for Score implementations:
+
+@table @gcctabopt
+@item -meb
+@opindex meb
+Compile code for big-endian mode.  This is the default.
+
+@item -mel
+@opindex mel
+Compile code for little-endian mode.
+
+@item -mnhwloop
+@opindex mnhwloop
+Disable generation of @code{bcnz} instructions.
+
+@item -muls
+@opindex muls
+Enable generation of unaligned load and store instructions.
+
+@item -mmac
+@opindex mmac
+Enable the use of multiply-accumulate instructions. Disabled by default.
+
+@item -mscore5
+@opindex mscore5
+Specify the SCORE5 as the target architecture.
+
+@item -mscore5u
+@opindex mscore5u
+Specify the SCORE5U of the target architecture.
+
+@item -mscore7
+@opindex mscore7
+Specify the SCORE7 as the target architecture. This is the default.
+
+@item -mscore7d
+@opindex mscore7d
+Specify the SCORE7D as the target architecture.
+@end table
+
+@node SH Options
+@subsection SH Options
+
+These @samp{-m} options are defined for the SH implementations:
+
+@table @gcctabopt
+@item -m1
+@opindex m1
+Generate code for the SH1.
+
+@item -m2
+@opindex m2
+Generate code for the SH2.
+
+@item -m2e
+Generate code for the SH2e.
+
+@item -m2a-nofpu
+@opindex m2a-nofpu
+Generate code for the SH2a without FPU, or for a SH2a-FPU in such a way
+that the floating-point unit is not used.
+
+@item -m2a-single-only
+@opindex m2a-single-only
+Generate code for the SH2a-FPU, in such a way that no double-precision
+floating-point operations are used.
+
+@item -m2a-single
+@opindex m2a-single
+Generate code for the SH2a-FPU assuming the floating-point unit is in
+single-precision mode by default.
+
+@item -m2a
+@opindex m2a
+Generate code for the SH2a-FPU assuming the floating-point unit is in
+double-precision mode by default.
+
+@item -m3
+@opindex m3
+Generate code for the SH3.
+
+@item -m3e
+@opindex m3e
+Generate code for the SH3e.
+
+@item -m4-nofpu
+@opindex m4-nofpu
+Generate code for the SH4 without a floating-point unit.
+
+@item -m4-single-only
+@opindex m4-single-only
+Generate code for the SH4 with a floating-point unit that only
+supports single-precision arithmetic.
+
+@item -m4-single
+@opindex m4-single
+Generate code for the SH4 assuming the floating-point unit is in
+single-precision mode by default.
+
+@item -m4
+@opindex m4
+Generate code for the SH4.
+
+@item -m4a-nofpu
+@opindex m4a-nofpu
+Generate code for the SH4al-dsp, or for a SH4a in such a way that the
+floating-point unit is not used.
+
+@item -m4a-single-only
+@opindex m4a-single-only
+Generate code for the SH4a, in such a way that no double-precision
+floating-point operations are used.
+
+@item -m4a-single
+@opindex m4a-single
+Generate code for the SH4a assuming the floating-point unit is in
+single-precision mode by default.
+
+@item -m4a
+@opindex m4a
+Generate code for the SH4a.
+
+@item -m4al
+@opindex m4al
+Same as @option{-m4a-nofpu}, except that it implicitly passes
+@option{-dsp} to the assembler.  GCC doesn't generate any DSP
+instructions at the moment.
+
+@item -mb
+@opindex mb
+Compile code for the processor in big-endian mode.
+
+@item -ml
+@opindex ml
+Compile code for the processor in little-endian mode.
+
+@item -mdalign
+@opindex mdalign
+Align doubles at 64-bit boundaries.  Note that this changes the calling
+conventions, and thus some functions from the standard C library do
+not work unless you recompile it first with @option{-mdalign}.
+
+@item -mrelax
+@opindex mrelax
+Shorten some address references at link time, when possible; uses the
+linker option @option{-relax}.
+
+@item -mbigtable
+@opindex mbigtable
+Use 32-bit offsets in @code{switch} tables.  The default is to use
+16-bit offsets.
+
+@item -mbitops
+@opindex mbitops
+Enable the use of bit manipulation instructions on SH2A.
+
+@item -mfmovd
+@opindex mfmovd
+Enable the use of the instruction @code{fmovd}.  Check @option{-mdalign} for
+alignment constraints.
+
+@item -mhitachi
+@opindex mhitachi
+Comply with the calling conventions defined by Renesas.
+
+@item -mrenesas
+@opindex mhitachi
+Comply with the calling conventions defined by Renesas.
+
+@item -mno-renesas
+@opindex mhitachi
+Comply with the calling conventions defined for GCC before the Renesas
+conventions were available.  This option is the default for all
+targets of the SH toolchain.
+
+@item -mnomacsave
+@opindex mnomacsave
+Mark the @code{MAC} register as call-clobbered, even if
+@option{-mhitachi} is given.
+
+@item -mieee
+@itemx -mno-ieee
+@opindex mieee
+@opindex mnoieee
+Control the IEEE compliance of floating-point comparisons, which affects the
+handling of cases where the result of a comparison is unordered.  By default
+@option{-mieee} is implicitly enabled.  If @option{-ffinite-math-only} is
+enabled @option{-mno-ieee} is implicitly set, which results in faster
+floating-point greater-equal and less-equal comparisons.  The implcit settings
+can be overridden by specifying either @option{-mieee} or @option{-mno-ieee}.
+
+@item -minline-ic_invalidate
+@opindex minline-ic_invalidate
+Inline code to invalidate instruction cache entries after setting up
+nested function trampolines.
+This option has no effect if @option{-musermode} is in effect and the selected
+code generation option (e.g. @option{-m4}) does not allow the use of the @code{icbi}
+instruction.
+If the selected code generation option does not allow the use of the @code{icbi}
+instruction, and @option{-musermode} is not in effect, the inlined code
+manipulates the instruction cache address array directly with an associative
+write.  This not only requires privileged mode at run time, but it also
+fails if the cache line had been mapped via the TLB and has become unmapped.
+
+@item -misize
+@opindex misize
+Dump instruction size and location in the assembly code.
+
+@item -mpadstruct
+@opindex mpadstruct
+This option is deprecated.  It pads structures to multiple of 4 bytes,
+which is incompatible with the SH ABI@.
+
+@item -matomic-model=@var{model}
+@opindex matomic-model=@var{model}
+Sets the model of atomic operations and additional parameters as a comma
+separated list.  For details on the atomic built-in functions see
+@ref{__atomic Builtins}.  The following models and parameters are supported:
+
+@table @samp
+
+@item none
+Disable compiler generated atomic sequences and emit library calls for atomic
+operations.  This is the default if the target is not @code{sh-*-linux*}.
+
+@item soft-gusa
+Generate GNU/Linux compatible gUSA software atomic sequences for the atomic
+built-in functions.  The generated atomic sequences require additional support
+from the interrupt/exception handling code of the system and are only suitable
+for SH3* and SH4* single-core systems.  This option is enabled by default when
+the target is @code{sh-*-linux*} and SH3* or SH4*.  When the target is SH4A,
+this option will also partially utilize the hardware atomic instructions
+@code{movli.l} and @code{movco.l} to create more efficient code, unless
+@samp{strict} is specified.  
+
+@item soft-tcb
+Generate software atomic sequences that use a variable in the thread control
+block.  This is a variation of the gUSA sequences which can also be used on
+SH1* and SH2* targets.  The generated atomic sequences require additional
+support from the interrupt/exception handling code of the system and are only
+suitable for single-core systems.  When using this model, the @samp{gbr-offset=}
+parameter has to be specified as well.
+
+@item soft-imask
+Generate software atomic sequences that temporarily disable interrupts by
+setting @code{SR.IMASK = 1111}.  This model works only when the program runs
+in privileged mode and is only suitable for single-core systems.  Additional
+support from the interrupt/exception handling code of the system is not
+required.  This model is enabled by default when the target is
+@code{sh-*-linux*} and SH1* or SH2*.
+
+@item hard-llcs
+Generate hardware atomic sequences using the @code{movli.l} and @code{movco.l}
+instructions only.  This is only available on SH4A and is suitable for
+multi-core systems.  Since the hardware instructions support only 32 bit atomic
+variables access to 8 or 16 bit variables is emulated with 32 bit accesses.
+Code compiled with this option will also be compatible with other software
+atomic model interrupt/exception handling systems if executed on an SH4A
+system.  Additional support from the interrupt/exception handling code of the
+system is not required for this model.
+
+@item gbr-offset=
+This parameter specifies the offset in bytes of the variable in the thread
+control block structure that should be used by the generated atomic sequences
+when the @samp{soft-tcb} model has been selected.  For other models this
+parameter is ignored.  The specified value must be an integer multiple of four
+and in the range 0-1020.
+
+@item strict
+This parameter prevents mixed usage of multiple atomic models, even though they
+would be compatible, and will make the compiler generate atomic sequences of the
+specified model only.
+
+@end table
+
+@item -mtas
+@opindex mtas
+Generate the @code{tas.b} opcode for @code{__atomic_test_and_set}.
+Notice that depending on the particular hardware and software configuration
+this can degrade overall performance due to the operand cache line flushes
+that are implied by the @code{tas.b} instruction.  On multi-core SH4A
+processors the @code{tas.b} instruction must be used with caution since it
+can result in data corruption for certain cache configurations.
+
+@item -mspace
+@opindex mspace
+Optimize for space instead of speed.  Implied by @option{-Os}.
+
+@item -mprefergot
+@opindex mprefergot
+When generating position-independent code, emit function calls using
+the Global Offset Table instead of the Procedure Linkage Table.
+
+@item -musermode
+@opindex musermode
+Don't generate privileged mode only code.  This option
+implies @option{-mno-inline-ic_invalidate}
+if the inlined code would not work in user mode.
+This is the default when the target is @code{sh-*-linux*}.
+
+@item -multcost=@var{number}
+@opindex multcost=@var{number}
+Set the cost to assume for a multiply insn.
+
+@item -mdiv=@var{strategy}
+@opindex mdiv=@var{strategy}
+Set the division strategy to be used for integer division operations.
+For SHmedia @var{strategy} can be one of: 
+
+@table @samp
+
+@item fp 
+Performs the operation in floating point.  This has a very high latency,
+but needs only a few instructions, so it might be a good choice if
+your code has enough easily-exploitable ILP to allow the compiler to
+schedule the floating-point instructions together with other instructions.
+Division by zero causes a floating-point exception.
+
+@item inv
+Uses integer operations to calculate the inverse of the divisor,
+and then multiplies the dividend with the inverse.  This strategy allows
+CSE and hoisting of the inverse calculation.  Division by zero calculates
+an unspecified result, but does not trap.
+
+@item inv:minlat
+A variant of @samp{inv} where, if no CSE or hoisting opportunities
+have been found, or if the entire operation has been hoisted to the same
+place, the last stages of the inverse calculation are intertwined with the
+final multiply to reduce the overall latency, at the expense of using a few
+more instructions, and thus offering fewer scheduling opportunities with
+other code.
+
+@item call
+Calls a library function that usually implements the @samp{inv:minlat}
+strategy.
+This gives high code density for @code{m5-*media-nofpu} compilations.
+
+@item call2
+Uses a different entry point of the same library function, where it
+assumes that a pointer to a lookup table has already been set up, which
+exposes the pointer load to CSE and code hoisting optimizations.
+
+@item inv:call
+@itemx inv:call2
+@itemx inv:fp
+Use the @samp{inv} algorithm for initial
+code generation, but if the code stays unoptimized, revert to the @samp{call},
+@samp{call2}, or @samp{fp} strategies, respectively.  Note that the
+potentially-trapping side effect of division by zero is carried by a
+separate instruction, so it is possible that all the integer instructions
+are hoisted out, but the marker for the side effect stays where it is.
+A recombination to floating-point operations or a call is not possible
+in that case.
+
+@item inv20u
+@itemx inv20l
+Variants of the @samp{inv:minlat} strategy.  In the case
+that the inverse calculation is not separated from the multiply, they speed
+up division where the dividend fits into 20 bits (plus sign where applicable)
+by inserting a test to skip a number of operations in this case; this test
+slows down the case of larger dividends.  @samp{inv20u} assumes the case of a such
+a small dividend to be unlikely, and @samp{inv20l} assumes it to be likely.
+
+@end table
+
+For targets other than SHmedia @var{strategy} can be one of:
+
+@table @samp
+
+@item call-div1
+Calls a library function that uses the single-step division instruction
+@code{div1} to perform the operation.  Division by zero calculates an
+unspecified result and does not trap.  This is the default except for SH4,
+SH2A and SHcompact.
+
+@item call-fp
+Calls a library function that performs the operation in double precision
+floating point.  Division by zero causes a floating-point exception.  This is
+the default for SHcompact with FPU.  Specifying this for targets that do not
+have a double precision FPU will default to @code{call-div1}.
+
+@item call-table
+Calls a library function that uses a lookup table for small divisors and
+the @code{div1} instruction with case distinction for larger divisors.  Division
+by zero calculates an unspecified result and does not trap.  This is the default
+for SH4.  Specifying this for targets that do not have dynamic shift
+instructions will default to @code{call-div1}.
+
+@end table
+
+When a division strategy has not been specified the default strategy will be
+selected based on the current target.  For SH2A the default strategy is to
+use the @code{divs} and @code{divu} instructions instead of library function
+calls.
+
+@item -maccumulate-outgoing-args
+@opindex maccumulate-outgoing-args
+Reserve space once for outgoing arguments in the function prologue rather
+than around each call.  Generally beneficial for performance and size.  Also
+needed for unwinding to avoid changing the stack frame around conditional code.
+
+@item -mdivsi3_libfunc=@var{name}
+@opindex mdivsi3_libfunc=@var{name}
+Set the name of the library function used for 32-bit signed division to
+@var{name}.
+This only affects the name used in the @samp{call} and @samp{inv:call}
+division strategies, and the compiler still expects the same
+sets of input/output/clobbered registers as if this option were not present.
+
+@item -mfixed-range=@var{register-range}
+@opindex mfixed-range
+Generate code treating the given register range as fixed registers.
+A fixed register is one that the register allocator can not use.  This is
+useful when compiling kernel code.  A register range is specified as
+two registers separated by a dash.  Multiple register ranges can be
+specified separated by a comma.
+
+@item -mindexed-addressing
+@opindex mindexed-addressing
+Enable the use of the indexed addressing mode for SHmedia32/SHcompact.
+This is only safe if the hardware and/or OS implement 32-bit wrap-around
+semantics for the indexed addressing mode.  The architecture allows the
+implementation of processors with 64-bit MMU, which the OS could use to
+get 32-bit addressing, but since no current hardware implementation supports
+this or any other way to make the indexed addressing mode safe to use in
+the 32-bit ABI, the default is @option{-mno-indexed-addressing}.
+
+@item -mgettrcost=@var{number}
+@opindex mgettrcost=@var{number}
+Set the cost assumed for the @code{gettr} instruction to @var{number}.
+The default is 2 if @option{-mpt-fixed} is in effect, 100 otherwise.
+
+@item -mpt-fixed
+@opindex mpt-fixed
+Assume @code{pt*} instructions won't trap.  This generally generates
+better-scheduled code, but is unsafe on current hardware.
+The current architecture
+definition says that @code{ptabs} and @code{ptrel} trap when the target 
+anded with 3 is 3.
+This has the unintentional effect of making it unsafe to schedule these
+instructions before a branch, or hoist them out of a loop.  For example,
+@code{__do_global_ctors}, a part of @file{libgcc}
+that runs constructors at program
+startup, calls functions in a list which is delimited by @minus{}1.  With the
+@option{-mpt-fixed} option, the @code{ptabs} is done before testing against @minus{}1.
+That means that all the constructors run a bit more quickly, but when
+the loop comes to the end of the list, the program crashes because @code{ptabs}
+loads @minus{}1 into a target register.  
+
+Since this option is unsafe for any
+hardware implementing the current architecture specification, the default
+is @option{-mno-pt-fixed}.  Unless specified explicitly with 
+@option{-mgettrcost}, @option{-mno-pt-fixed} also implies @option{-mgettrcost=100};
+this deters register allocation from using target registers for storing
+ordinary integers.
+
+@item -minvalid-symbols
+@opindex minvalid-symbols
+Assume symbols might be invalid.  Ordinary function symbols generated by
+the compiler are always valid to load with
+@code{movi}/@code{shori}/@code{ptabs} or
+@code{movi}/@code{shori}/@code{ptrel},
+but with assembler and/or linker tricks it is possible
+to generate symbols that cause @code{ptabs} or @code{ptrel} to trap.
+This option is only meaningful when @option{-mno-pt-fixed} is in effect.
+It prevents cross-basic-block CSE, hoisting and most scheduling
+of symbol loads.  The default is @option{-mno-invalid-symbols}.
+
+@item -mbranch-cost=@var{num}
+@opindex mbranch-cost=@var{num}
+Assume @var{num} to be the cost for a branch instruction.  Higher numbers
+make the compiler try to generate more branch-free code if possible.  
+If not specified the value is selected depending on the processor type that
+is being compiled for.
+
+@item -mzdcbranch
+@itemx -mno-zdcbranch
+@opindex mzdcbranch
+@opindex mno-zdcbranch
+Assume (do not assume) that zero displacement conditional branch instructions
+@code{bt} and @code{bf} are fast.  If @option{-mzdcbranch} is specified, the
+compiler will try to prefer zero displacement branch code sequences.  This is
+enabled by default when generating code for SH4 and SH4A.  It can be explicitly
+disabled by specifying @option{-mno-zdcbranch}.
+
+@item -mcbranchdi
+@opindex mcbranchdi
+Enable the @code{cbranchdi4} instruction pattern.
+
+@item -mcmpeqdi
+@opindex mcmpeqdi
+Emit the @code{cmpeqdi_t} instruction pattern even when @option{-mcbranchdi}
+is in effect.
+
+@item -mfused-madd
+@itemx -mno-fused-madd
+@opindex mfused-madd
+@opindex mno-fused-madd
+Generate code that uses (does not use) the floating-point multiply and
+accumulate instructions.  These instructions are generated by default
+if hardware floating point is used.  The machine-dependent
+@option{-mfused-madd} option is now mapped to the machine-independent
+@option{-ffp-contract=fast} option, and @option{-mno-fused-madd} is
+mapped to @option{-ffp-contract=off}.
+
+@item -mfsca
+@itemx -mno-fsca
+@opindex mfsca
+@opindex mno-fsca
+Allow or disallow the compiler to emit the @code{fsca} instruction for sine
+and cosine approximations.  The option @code{-mfsca} must be used in
+combination with @code{-funsafe-math-optimizations}.  It is enabled by default
+when generating code for SH4A.  Using @code{-mno-fsca} disables sine and cosine
+approximations even if @code{-funsafe-math-optimizations} is in effect.
+
+@item -mfsrra
+@itemx -mno-fsrra
+@opindex mfsrra
+@opindex mno-fsrra
+Allow or disallow the compiler to emit the @code{fsrra} instruction for
+reciprocal square root approximations.  The option @code{-mfsrra} must be used
+in combination with @code{-funsafe-math-optimizations} and
+@code{-ffinite-math-only}.  It is enabled by default when generating code for
+SH4A.  Using @code{-mno-fsrra} disables reciprocal square root approximations
+even if @code{-funsafe-math-optimizations} and @code{-ffinite-math-only} are
+in effect.
+
+@item -mpretend-cmove
+@opindex mpretend-cmove
+Prefer zero-displacement conditional branches for conditional move instruction
+patterns.  This can result in faster code on the SH4 processor.
+
+@end table
+
+@node Solaris 2 Options
+@subsection Solaris 2 Options
+@cindex Solaris 2 options
+
+These @samp{-m} options are supported on Solaris 2:
+
+@table @gcctabopt
+@item -mimpure-text
+@opindex mimpure-text
+@option{-mimpure-text}, used in addition to @option{-shared}, tells
+the compiler to not pass @option{-z text} to the linker when linking a
+shared object.  Using this option, you can link position-dependent
+code into a shared object.
+
+@option{-mimpure-text} suppresses the ``relocations remain against
+allocatable but non-writable sections'' linker error message.
+However, the necessary relocations trigger copy-on-write, and the
+shared object is not actually shared across processes.  Instead of
+using @option{-mimpure-text}, you should compile all source code with
+@option{-fpic} or @option{-fPIC}.
+
+@end table
+
+These switches are supported in addition to the above on Solaris 2:
+
+@table @gcctabopt
+@item -pthreads
+@opindex pthreads
+Add support for multithreading using the POSIX threads library.  This
+option sets flags for both the preprocessor and linker.  This option does
+not affect the thread safety of object code produced  by the compiler or
+that of libraries supplied with it.
+
+@item -pthread
+@opindex pthread
+This is a synonym for @option{-pthreads}.
+@end table
+
+@node SPARC Options
+@subsection SPARC Options
+@cindex SPARC options
+
+These @samp{-m} options are supported on the SPARC:
+
+@table @gcctabopt
+@item -mno-app-regs
+@itemx -mapp-regs
+@opindex mno-app-regs
+@opindex mapp-regs
+Specify @option{-mapp-regs} to generate output using the global registers
+2 through 4, which the SPARC SVR4 ABI reserves for applications.  Like the
+global register 1, each global register 2 through 4 is then treated as an
+allocable register that is clobbered by function calls.  This is the default.
+
+To be fully SVR4 ABI-compliant at the cost of some performance loss,
+specify @option{-mno-app-regs}.  You should compile libraries and system
+software with this option.
+
+@item -mflat
+@itemx -mno-flat
+@opindex mflat
+@opindex mno-flat
+With @option{-mflat}, the compiler does not generate save/restore instructions
+and uses a ``flat'' or single register window model.  This model is compatible
+with the regular register window model.  The local registers and the input
+registers (0--5) are still treated as ``call-saved'' registers and are
+saved on the stack as needed.
+
+With @option{-mno-flat} (the default), the compiler generates save/restore
+instructions (except for leaf functions).  This is the normal operating mode.
+
+@item -mfpu
+@itemx -mhard-float
+@opindex mfpu
+@opindex mhard-float
+Generate output containing floating-point instructions.  This is the
+default.
+
+@item -mno-fpu
+@itemx -msoft-float
+@opindex mno-fpu
+@opindex msoft-float
+Generate output containing library calls for floating point.
+@strong{Warning:} the requisite libraries are not available for all SPARC
+targets.  Normally the facilities of the machine's usual C compiler are
+used, but this cannot be done directly in cross-compilation.  You must make
+your own arrangements to provide suitable library functions for
+cross-compilation.  The embedded targets @samp{sparc-*-aout} and
+@samp{sparclite-*-*} do provide software floating-point support.
+
+@option{-msoft-float} changes the calling convention in the output file;
+therefore, it is only useful if you compile @emph{all} of a program with
+this option.  In particular, you need to compile @file{libgcc.a}, the
+library that comes with GCC, with @option{-msoft-float} in order for
+this to work.
+
+@item -mhard-quad-float
+@opindex mhard-quad-float
+Generate output containing quad-word (long double) floating-point
+instructions.
+
+@item -msoft-quad-float
+@opindex msoft-quad-float
+Generate output containing library calls for quad-word (long double)
+floating-point instructions.  The functions called are those specified
+in the SPARC ABI@.  This is the default.
+
+As of this writing, there are no SPARC implementations that have hardware
+support for the quad-word floating-point instructions.  They all invoke
+a trap handler for one of these instructions, and then the trap handler
+emulates the effect of the instruction.  Because of the trap handler overhead,
+this is much slower than calling the ABI library routines.  Thus the
+@option{-msoft-quad-float} option is the default.
+
+@item -mno-unaligned-doubles
+@itemx -munaligned-doubles
+@opindex mno-unaligned-doubles
+@opindex munaligned-doubles
+Assume that doubles have 8-byte alignment.  This is the default.
+
+With @option{-munaligned-doubles}, GCC assumes that doubles have 8-byte
+alignment only if they are contained in another type, or if they have an
+absolute address.  Otherwise, it assumes they have 4-byte alignment.
+Specifying this option avoids some rare compatibility problems with code
+generated by other compilers.  It is not the default because it results
+in a performance loss, especially for floating-point code.
+
+@item -muser-mode
+@itemx -mno-user-mode
+@opindex muser-mode
+@opindex mno-user-mode
+Do not generate code that can only run in supervisor mode.  This is relevant
+only for the @code{casa} instruction emitted for the LEON3 processor.  The
+default is @option{-mno-user-mode}.
+
+@item -mno-faster-structs
+@itemx -mfaster-structs
+@opindex mno-faster-structs
+@opindex mfaster-structs
+With @option{-mfaster-structs}, the compiler assumes that structures
+should have 8-byte alignment.  This enables the use of pairs of
+@code{ldd} and @code{std} instructions for copies in structure
+assignment, in place of twice as many @code{ld} and @code{st} pairs.
+However, the use of this changed alignment directly violates the SPARC
+ABI@.  Thus, it's intended only for use on targets where the developer
+acknowledges that their resulting code is not directly in line with
+the rules of the ABI@.
+
+@item -mcpu=@var{cpu_type}
+@opindex mcpu
+Set the instruction set, register set, and instruction scheduling parameters
+for machine type @var{cpu_type}.  Supported values for @var{cpu_type} are
+@samp{v7}, @samp{cypress}, @samp{v8}, @samp{supersparc}, @samp{hypersparc},
+@samp{leon}, @samp{leon3}, @samp{sparclite}, @samp{f930}, @samp{f934},
+@samp{sparclite86x}, @samp{sparclet}, @samp{tsc701}, @samp{v9},
+@samp{ultrasparc}, @samp{ultrasparc3}, @samp{niagara}, @samp{niagara2},
+@samp{niagara3} and @samp{niagara4}.
+
+Native Solaris and GNU/Linux toolchains also support the value @samp{native},
+which selects the best architecture option for the host processor.
+@option{-mcpu=native} has no effect if GCC does not recognize
+the processor.
+
+Default instruction scheduling parameters are used for values that select
+an architecture and not an implementation.  These are @samp{v7}, @samp{v8},
+@samp{sparclite}, @samp{sparclet}, @samp{v9}.
+
+Here is a list of each supported architecture and their supported
+implementations.
+
+@table @asis
+@item v7
+cypress
+
+@item v8
+supersparc, hypersparc, leon, leon3
+
+@item sparclite
+f930, f934, sparclite86x
+
+@item sparclet
+tsc701
+
+@item v9
+ultrasparc, ultrasparc3, niagara, niagara2, niagara3, niagara4
+@end table
+
+By default (unless configured otherwise), GCC generates code for the V7
+variant of the SPARC architecture.  With @option{-mcpu=cypress}, the compiler
+additionally optimizes it for the Cypress CY7C602 chip, as used in the
+SPARCStation/SPARCServer 3xx series.  This is also appropriate for the older
+SPARCStation 1, 2, IPX etc.
+
+With @option{-mcpu=v8}, GCC generates code for the V8 variant of the SPARC
+architecture.  The only difference from V7 code is that the compiler emits
+the integer multiply and integer divide instructions which exist in SPARC-V8
+but not in SPARC-V7.  With @option{-mcpu=supersparc}, the compiler additionally
+optimizes it for the SuperSPARC chip, as used in the SPARCStation 10, 1000 and
+2000 series.
+
+With @option{-mcpu=sparclite}, GCC generates code for the SPARClite variant of
+the SPARC architecture.  This adds the integer multiply, integer divide step
+and scan (@code{ffs}) instructions which exist in SPARClite but not in SPARC-V7.
+With @option{-mcpu=f930}, the compiler additionally optimizes it for the
+Fujitsu MB86930 chip, which is the original SPARClite, with no FPU@.  With
+@option{-mcpu=f934}, the compiler additionally optimizes it for the Fujitsu
+MB86934 chip, which is the more recent SPARClite with FPU@.
+
+With @option{-mcpu=sparclet}, GCC generates code for the SPARClet variant of
+the SPARC architecture.  This adds the integer multiply, multiply/accumulate,
+integer divide step and scan (@code{ffs}) instructions which exist in SPARClet
+but not in SPARC-V7.  With @option{-mcpu=tsc701}, the compiler additionally
+optimizes it for the TEMIC SPARClet chip.
+
+With @option{-mcpu=v9}, GCC generates code for the V9 variant of the SPARC
+architecture.  This adds 64-bit integer and floating-point move instructions,
+3 additional floating-point condition code registers and conditional move
+instructions.  With @option{-mcpu=ultrasparc}, the compiler additionally
+optimizes it for the Sun UltraSPARC I/II/IIi chips.  With
+@option{-mcpu=ultrasparc3}, the compiler additionally optimizes it for the
+Sun UltraSPARC III/III+/IIIi/IIIi+/IV/IV+ chips.  With
+@option{-mcpu=niagara}, the compiler additionally optimizes it for
+Sun UltraSPARC T1 chips.  With @option{-mcpu=niagara2}, the compiler
+additionally optimizes it for Sun UltraSPARC T2 chips. With
+@option{-mcpu=niagara3}, the compiler additionally optimizes it for Sun
+UltraSPARC T3 chips.  With @option{-mcpu=niagara4}, the compiler
+additionally optimizes it for Sun UltraSPARC T4 chips.
+
+@item -mtune=@var{cpu_type}
+@opindex mtune
+Set the instruction scheduling parameters for machine type
+@var{cpu_type}, but do not set the instruction set or register set that the
+option @option{-mcpu=@var{cpu_type}} does.
+
+The same values for @option{-mcpu=@var{cpu_type}} can be used for
+@option{-mtune=@var{cpu_type}}, but the only useful values are those
+that select a particular CPU implementation.  Those are @samp{cypress},
+@samp{supersparc}, @samp{hypersparc}, @samp{leon}, @samp{leon3}, @samp{f930},
+@samp{f934}, @samp{sparclite86x}, @samp{tsc701}, @samp{ultrasparc},
+@samp{ultrasparc3}, @samp{niagara}, @samp{niagara2}, @samp{niagara3} and
+@samp{niagara4}.  With native Solaris and GNU/Linux toolchains, @samp{native}
+can also be used.
+
+@item -mv8plus
+@itemx -mno-v8plus
+@opindex mv8plus
+@opindex mno-v8plus
+With @option{-mv8plus}, GCC generates code for the SPARC-V8+ ABI@.  The
+difference from the V8 ABI is that the global and out registers are
+considered 64 bits wide.  This is enabled by default on Solaris in 32-bit
+mode for all SPARC-V9 processors.
+
+@item -mvis
+@itemx -mno-vis
+@opindex mvis
+@opindex mno-vis
+With @option{-mvis}, GCC generates code that takes advantage of the UltraSPARC
+Visual Instruction Set extensions.  The default is @option{-mno-vis}.
+
+@item -mvis2
+@itemx -mno-vis2
+@opindex mvis2
+@opindex mno-vis2
+With @option{-mvis2}, GCC generates code that takes advantage of
+version 2.0 of the UltraSPARC Visual Instruction Set extensions.  The
+default is @option{-mvis2} when targeting a cpu that supports such
+instructions, such as UltraSPARC-III and later.  Setting @option{-mvis2}
+also sets @option{-mvis}.
+
+@item -mvis3
+@itemx -mno-vis3
+@opindex mvis3
+@opindex mno-vis3
+With @option{-mvis3}, GCC generates code that takes advantage of
+version 3.0 of the UltraSPARC Visual Instruction Set extensions.  The
+default is @option{-mvis3} when targeting a cpu that supports such
+instructions, such as niagara-3 and later.  Setting @option{-mvis3}
+also sets @option{-mvis2} and @option{-mvis}.
+
+@item -mcbcond
+@itemx -mno-cbcond
+@opindex mcbcond
+@opindex mno-cbcond
+With @option{-mcbcond}, GCC generates code that takes advantage of
+compare-and-branch instructions, as defined in the Sparc Architecture 2011.
+The default is @option{-mcbcond} when targeting a cpu that supports such
+instructions, such as niagara-4 and later.
+
+@item -mpopc
+@itemx -mno-popc
+@opindex mpopc
+@opindex mno-popc
+With @option{-mpopc}, GCC generates code that takes advantage of the UltraSPARC
+population count instruction.  The default is @option{-mpopc}
+when targeting a cpu that supports such instructions, such as Niagara-2 and
+later.
+
+@item -mfmaf
+@itemx -mno-fmaf
+@opindex mfmaf
+@opindex mno-fmaf
+With @option{-mfmaf}, GCC generates code that takes advantage of the UltraSPARC
+Fused Multiply-Add Floating-point extensions.  The default is @option{-mfmaf}
+when targeting a cpu that supports such instructions, such as Niagara-3 and
+later.
+
+@item -mfix-at697f
+@opindex mfix-at697f
+Enable the documented workaround for the single erratum of the Atmel AT697F
+processor (which corresponds to erratum #13 of the AT697E processor).
+
+@item -mfix-ut699
+@opindex mfix-ut699
+Enable the documented workarounds for the floating-point errata and the data
+cache nullify errata of the UT699 processor.
+@end table
+
+These @samp{-m} options are supported in addition to the above
+on SPARC-V9 processors in 64-bit environments:
+
+@table @gcctabopt
+@item -m32
+@itemx -m64
+@opindex m32
+@opindex m64
+Generate code for a 32-bit or 64-bit environment.
+The 32-bit environment sets int, long and pointer to 32 bits.
+The 64-bit environment sets int to 32 bits and long and pointer
+to 64 bits.
+
+@item -mcmodel=@var{which}
+@opindex mcmodel
+Set the code model to one of
+
+@table @samp
+@item medlow
+The Medium/Low code model: 64-bit addresses, programs
+must be linked in the low 32 bits of memory.  Programs can be statically
+or dynamically linked.
+
+@item medmid
+The Medium/Middle code model: 64-bit addresses, programs
+must be linked in the low 44 bits of memory, the text and data segments must
+be less than 2GB in size and the data segment must be located within 2GB of
+the text segment.
+
+@item medany
+The Medium/Anywhere code model: 64-bit addresses, programs
+may be linked anywhere in memory, the text and data segments must be less
+than 2GB in size and the data segment must be located within 2GB of the
+text segment.
+
+@item embmedany
+The Medium/Anywhere code model for embedded systems:
+64-bit addresses, the text and data segments must be less than 2GB in
+size, both starting anywhere in memory (determined at link time).  The
+global register %g4 points to the base of the data segment.  Programs
+are statically linked and PIC is not supported.
+@end table
+
+@item -mmemory-model=@var{mem-model}
+@opindex mmemory-model
+Set the memory model in force on the processor to one of
+
+@table @samp
+@item default
+The default memory model for the processor and operating system.
+
+@item rmo
+Relaxed Memory Order
+
+@item pso
+Partial Store Order
+
+@item tso
+Total Store Order
+
+@item sc
+Sequential Consistency
+@end table
+
+These memory models are formally defined in Appendix D of the Sparc V9
+architecture manual, as set in the processor's @code{PSTATE.MM} field.
+
+@item -mstack-bias
+@itemx -mno-stack-bias
+@opindex mstack-bias
+@opindex mno-stack-bias
+With @option{-mstack-bias}, GCC assumes that the stack pointer, and
+frame pointer if present, are offset by @minus{}2047 which must be added back
+when making stack frame references.  This is the default in 64-bit mode.
+Otherwise, assume no such offset is present.
+@end table
+
+@node SPU Options
+@subsection SPU Options
+@cindex SPU options
+
+These @samp{-m} options are supported on the SPU:
+
+@table @gcctabopt
+@item -mwarn-reloc
+@itemx -merror-reloc
+@opindex mwarn-reloc
+@opindex merror-reloc
+
+The loader for SPU does not handle dynamic relocations.  By default, GCC
+gives an error when it generates code that requires a dynamic
+relocation.  @option{-mno-error-reloc} disables the error,
+@option{-mwarn-reloc} generates a warning instead.
+
+@item -msafe-dma
+@itemx -munsafe-dma
+@opindex msafe-dma
+@opindex munsafe-dma
+
+Instructions that initiate or test completion of DMA must not be
+reordered with respect to loads and stores of the memory that is being
+accessed.
+With @option{-munsafe-dma} you must use the @code{volatile} keyword to protect
+memory accesses, but that can lead to inefficient code in places where the
+memory is known to not change.  Rather than mark the memory as volatile,
+you can use @option{-msafe-dma} to tell the compiler to treat
+the DMA instructions as potentially affecting all memory.  
+
+@item -mbranch-hints
+@opindex mbranch-hints
+
+By default, GCC generates a branch hint instruction to avoid
+pipeline stalls for always-taken or probably-taken branches.  A hint
+is not generated closer than 8 instructions away from its branch.
+There is little reason to disable them, except for debugging purposes,
+or to make an object a little bit smaller.
+
+@item -msmall-mem
+@itemx -mlarge-mem
+@opindex msmall-mem
+@opindex mlarge-mem
+
+By default, GCC generates code assuming that addresses are never larger
+than 18 bits.  With @option{-mlarge-mem} code is generated that assumes
+a full 32-bit address.
+
+@item -mstdmain
+@opindex mstdmain
+
+By default, GCC links against startup code that assumes the SPU-style
+main function interface (which has an unconventional parameter list).
+With @option{-mstdmain}, GCC links your program against startup
+code that assumes a C99-style interface to @code{main}, including a
+local copy of @code{argv} strings.
+
+@item -mfixed-range=@var{register-range}
+@opindex mfixed-range
+Generate code treating the given register range as fixed registers.
+A fixed register is one that the register allocator cannot use.  This is
+useful when compiling kernel code.  A register range is specified as
+two registers separated by a dash.  Multiple register ranges can be
+specified separated by a comma.
+
+@item -mea32
+@itemx -mea64
+@opindex mea32
+@opindex mea64
+Compile code assuming that pointers to the PPU address space accessed
+via the @code{__ea} named address space qualifier are either 32 or 64
+bits wide.  The default is 32 bits.  As this is an ABI-changing option,
+all object code in an executable must be compiled with the same setting.
+
+@item -maddress-space-conversion
+@itemx -mno-address-space-conversion
+@opindex maddress-space-conversion
+@opindex mno-address-space-conversion
+Allow/disallow treating the @code{__ea} address space as superset
+of the generic address space.  This enables explicit type casts
+between @code{__ea} and generic pointer as well as implicit
+conversions of generic pointers to @code{__ea} pointers.  The
+default is to allow address space pointer conversions.
+
+@item -mcache-size=@var{cache-size}
+@opindex mcache-size
+This option controls the version of libgcc that the compiler links to an
+executable and selects a software-managed cache for accessing variables
+in the @code{__ea} address space with a particular cache size.  Possible
+options for @var{cache-size} are @samp{8}, @samp{16}, @samp{32}, @samp{64}
+and @samp{128}.  The default cache size is 64KB.
+
+@item -matomic-updates
+@itemx -mno-atomic-updates
+@opindex matomic-updates
+@opindex mno-atomic-updates
+This option controls the version of libgcc that the compiler links to an
+executable and selects whether atomic updates to the software-managed
+cache of PPU-side variables are used.  If you use atomic updates, changes
+to a PPU variable from SPU code using the @code{__ea} named address space
+qualifier do not interfere with changes to other PPU variables residing
+in the same cache line from PPU code.  If you do not use atomic updates,
+such interference may occur; however, writing back cache lines is
+more efficient.  The default behavior is to use atomic updates.
+
+@item -mdual-nops
+@itemx -mdual-nops=@var{n}
+@opindex mdual-nops
+By default, GCC inserts nops to increase dual issue when it expects
+it to increase performance.  @var{n} can be a value from 0 to 10.  A
+smaller @var{n} inserts fewer nops.  10 is the default, 0 is the
+same as @option{-mno-dual-nops}.  Disabled with @option{-Os}.
+
+@item -mhint-max-nops=@var{n}
+@opindex mhint-max-nops
+Maximum number of nops to insert for a branch hint.  A branch hint must
+be at least 8 instructions away from the branch it is affecting.  GCC
+inserts up to @var{n} nops to enforce this, otherwise it does not
+generate the branch hint.
+
+@item -mhint-max-distance=@var{n}
+@opindex mhint-max-distance
+The encoding of the branch hint instruction limits the hint to be within
+256 instructions of the branch it is affecting.  By default, GCC makes
+sure it is within 125.
+
+@item -msafe-hints
+@opindex msafe-hints
+Work around a hardware bug that causes the SPU to stall indefinitely.
+By default, GCC inserts the @code{hbrp} instruction to make sure
+this stall won't happen.
+
+@end table
+
+@node System V Options
+@subsection Options for System V
+
+These additional options are available on System V Release 4 for
+compatibility with other compilers on those systems:
+
+@table @gcctabopt
+@item -G
+@opindex G
+Create a shared object.
+It is recommended that @option{-symbolic} or @option{-shared} be used instead.
+
+@item -Qy
+@opindex Qy
+Identify the versions of each tool used by the compiler, in a
+@code{.ident} assembler directive in the output.
+
+@item -Qn
+@opindex Qn
+Refrain from adding @code{.ident} directives to the output file (this is
+the default).
+
+@item -YP,@var{dirs}
+@opindex YP
+Search the directories @var{dirs}, and no others, for libraries
+specified with @option{-l}.
+
+@item -Ym,@var{dir}
+@opindex Ym
+Look in the directory @var{dir} to find the M4 preprocessor.
+The assembler uses this option.
+@c This is supposed to go with a -Yd for predefined M4 macro files, but
+@c the generic assembler that comes with Solaris takes just -Ym.
+@end table
+
+@node TILE-Gx Options
+@subsection TILE-Gx Options
+@cindex TILE-Gx options
+
+These @samp{-m} options are supported on the TILE-Gx:
+
+@table @gcctabopt
+@item -mcmodel=small
+@opindex mcmodel=small
+Generate code for the small model.  The distance for direct calls is
+limited to 500M in either direction.  PC-relative addresses are 32
+bits.  Absolute addresses support the full address range.
+
+@item -mcmodel=large
+@opindex mcmodel=large
+Generate code for the large model.  There is no limitation on call
+distance, pc-relative addresses, or absolute addresses.
+
+@item -mcpu=@var{name}
+@opindex mcpu
+Selects the type of CPU to be targeted.  Currently the only supported
+type is @samp{tilegx}.
+
+@item -m32
+@itemx -m64
+@opindex m32
+@opindex m64
+Generate code for a 32-bit or 64-bit environment.  The 32-bit
+environment sets int, long, and pointer to 32 bits.  The 64-bit
+environment sets int to 32 bits and long and pointer to 64 bits.
+@end table
+
+@node TILEPro Options
+@subsection TILEPro Options
+@cindex TILEPro options
+
+These @samp{-m} options are supported on the TILEPro:
+
+@table @gcctabopt
+@item -mcpu=@var{name}
+@opindex mcpu
+Selects the type of CPU to be targeted.  Currently the only supported
+type is @samp{tilepro}.
+
+@item -m32
+@opindex m32
+Generate code for a 32-bit environment, which sets int, long, and
+pointer to 32 bits.  This is the only supported behavior so the flag
+is essentially ignored.
+@end table
+
+@node V850 Options
+@subsection V850 Options
+@cindex V850 Options
+
+These @samp{-m} options are defined for V850 implementations:
+
+@table @gcctabopt
+@item -mlong-calls
+@itemx -mno-long-calls
+@opindex mlong-calls
+@opindex mno-long-calls
+Treat all calls as being far away (near).  If calls are assumed to be
+far away, the compiler always loads the function's address into a
+register, and calls indirect through the pointer.
+
+@item -mno-ep
+@itemx -mep
+@opindex mno-ep
+@opindex mep
+Do not optimize (do optimize) basic blocks that use the same index
+pointer 4 or more times to copy pointer into the @code{ep} register, and
+use the shorter @code{sld} and @code{sst} instructions.  The @option{-mep}
+option is on by default if you optimize.
+
+@item -mno-prolog-function
+@itemx -mprolog-function
+@opindex mno-prolog-function
+@opindex mprolog-function
+Do not use (do use) external functions to save and restore registers
+at the prologue and epilogue of a function.  The external functions
+are slower, but use less code space if more than one function saves
+the same number of registers.  The @option{-mprolog-function} option
+is on by default if you optimize.
+
+@item -mspace
+@opindex mspace
+Try to make the code as small as possible.  At present, this just turns
+on the @option{-mep} and @option{-mprolog-function} options.
+
+@item -mtda=@var{n}
+@opindex mtda
+Put static or global variables whose size is @var{n} bytes or less into
+the tiny data area that register @code{ep} points to.  The tiny data
+area can hold up to 256 bytes in total (128 bytes for byte references).
+
+@item -msda=@var{n}
+@opindex msda
+Put static or global variables whose size is @var{n} bytes or less into
+the small data area that register @code{gp} points to.  The small data
+area can hold up to 64 kilobytes.
+
+@item -mzda=@var{n}
+@opindex mzda
+Put static or global variables whose size is @var{n} bytes or less into
+the first 32 kilobytes of memory.
+
+@item -mv850
+@opindex mv850
+Specify that the target processor is the V850.
+
+@item -mv850e3v5
+@opindex mv850e3v5
+Specify that the target processor is the V850E3V5.  The preprocessor
+constant @samp{__v850e3v5__} is defined if this option is used.
+
+@item -mv850e2v4
+@opindex mv850e2v4
+Specify that the target processor is the V850E3V5.  This is an alias for
+the @option{-mv850e3v5} option.
+
+@item -mv850e2v3
+@opindex mv850e2v3
+Specify that the target processor is the V850E2V3.  The preprocessor
+constant @samp{__v850e2v3__} is defined if this option is used.
+
+@item -mv850e2
+@opindex mv850e2
+Specify that the target processor is the V850E2.  The preprocessor
+constant @samp{__v850e2__} is defined if this option is used.
+
+@item -mv850e1
+@opindex mv850e1
+Specify that the target processor is the V850E1.  The preprocessor
+constants @samp{__v850e1__} and @samp{__v850e__} are defined if
+this option is used.
+
+@item -mv850es
+@opindex mv850es
+Specify that the target processor is the V850ES.  This is an alias for
+the @option{-mv850e1} option.
+
+@item -mv850e
+@opindex mv850e
+Specify that the target processor is the V850E@.  The preprocessor
+constant @samp{__v850e__} is defined if this option is used.
+
+If neither @option{-mv850} nor @option{-mv850e} nor @option{-mv850e1}
+nor @option{-mv850e2} nor @option{-mv850e2v3} nor @option{-mv850e3v5}
+are defined then a default target processor is chosen and the
+relevant @samp{__v850*__} preprocessor constant is defined.
+
+The preprocessor constants @samp{__v850} and @samp{__v851__} are always
+defined, regardless of which processor variant is the target.
+
+@item -mdisable-callt
+@itemx -mno-disable-callt
+@opindex mdisable-callt
+@opindex mno-disable-callt
+This option suppresses generation of the @code{CALLT} instruction for the
+v850e, v850e1, v850e2, v850e2v3 and v850e3v5 flavors of the v850
+architecture.
+
+This option is enabled by default when the RH850 ABI is
+in use (see @option{-mrh850-abi}), and disabled by default when the
+GCC ABI is in use.  If @code{CALLT} instructions are being generated
+then the C preprocessor symbol @code{__V850_CALLT__} will be defined.
+
+@item -mrelax
+@itemx -mno-relax
+@opindex mrelax
+@opindex mno-relax
+Pass on (or do not pass on) the @option{-mrelax} command line option
+to the assembler.
+
+@item -mlong-jumps
+@itemx -mno-long-jumps
+@opindex mlong-jumps
+@opindex mno-long-jumps
+Disable (or re-enable) the generation of PC-relative jump instructions.
+
+@item -msoft-float
+@itemx -mhard-float
+@opindex msoft-float
+@opindex mhard-float
+Disable (or re-enable) the generation of hardware floating point
+instructions.  This option is only significant when the target
+architecture is @samp{V850E2V3} or higher.  If hardware floating point
+instructions are being generated then the C preprocessor symbol
+@code{__FPU_OK__} will be defined, otherwise the symbol
+@code{__NO_FPU__} will be defined.
+
+@item -mloop
+@opindex mloop
+Enables the use of the e3v5 LOOP instruction.  The use of this
+instruction is not enabled by default when the e3v5 architecture is
+selected because its use is still experimental.
+
+@item -mrh850-abi
+@itemx -mghs
+@opindex mrh850-abi
+@opindex mghs
+Enables support for the RH850 version of the V850 ABI.  This is the
+default.  With this version of the ABI the following rules apply:
+
+@itemize
+@item
+Integer sized structures and unions are returned via a memory pointer
+rather than a register.
+
+@item
+Large structures and unions (more than 8 bytes in size) are passed by
+value.
+
+@item
+Functions are aligned to 16-bit boundaries.
+
+@item
+The @option{-m8byte-align} command line option is supported.
+
+@item
+The @option{-mdisable-callt} command line option is enabled by
+default.  The @option{-mno-disable-callt} command line option is not
+supported.
+@end itemize
+
+When this version of the ABI is enabled the C preprocessor symbol
+@code{__V850_RH850_ABI__} is defined.
+
+@item -mgcc-abi
+@opindex mgcc-abi
+Enables support for the old GCC version of the V850 ABI.  With this
+version of the ABI the following rules apply:
+
+@itemize
+@item
+Integer sized structures and unions are returned in register @code{r10}.
+
+@item
+Large structures and unions (more than 8 bytes in size) are passed by
+reference.
+
+@item
+Functions are aligned to 32-bit boundaries, unless optimizing for
+size.
+
+@item
+The @option{-m8byte-align} command line option is not supported.
+
+@item
+The @option{-mdisable-callt} command line option is supported but not
+enabled by default.
+@end itemize
+
+When this version of the ABI is enabled the C preprocessor symbol
+@code{__V850_GCC_ABI__} is defined.
+
+@item -m8byte-align
+@itemx -mno-8byte-align
+@opindex m8byte-align
+@opindex mno-8byte-align
+Enables support for @code{doubles} and @code{long long} types to be
+aligned on 8-byte boundaries.  The default is to restrict the
+alignment of all objects to at most 4-bytes.  When
+@option{-m8byte-align} is in effect the C preprocessor symbol
+@code{__V850_8BYTE_ALIGN__} will be defined.
+
+@item -mbig-switch
+@opindex mbig-switch
+Generate code suitable for big switch tables.  Use this option only if
+the assembler/linker complain about out of range branches within a switch
+table.
+
+@item -mapp-regs
+@opindex mapp-regs
+This option causes r2 and r5 to be used in the code generated by
+the compiler.  This setting is the default.
+
+@item -mno-app-regs
+@opindex mno-app-regs
+This option causes r2 and r5 to be treated as fixed registers.
+
+@end table
+
+@node VAX Options
+@subsection VAX Options
+@cindex VAX options
+
+These @samp{-m} options are defined for the VAX:
+
+@table @gcctabopt
+@item -munix
+@opindex munix
+Do not output certain jump instructions (@code{aobleq} and so on)
+that the Unix assembler for the VAX cannot handle across long
+ranges.
+
+@item -mgnu
+@opindex mgnu
+Do output those jump instructions, on the assumption that the
+GNU assembler is being used.
+
+@item -mg
+@opindex mg
+Output code for G-format floating-point numbers instead of D-format.
+@end table
+
+@node VMS Options
+@subsection VMS Options
+
+These @samp{-m} options are defined for the VMS implementations:
+
+@table @gcctabopt
+@item -mvms-return-codes
+@opindex mvms-return-codes
+Return VMS condition codes from @code{main}. The default is to return POSIX-style
+condition (e.g.@ error) codes.
+
+@item -mdebug-main=@var{prefix}
+@opindex mdebug-main=@var{prefix}
+Flag the first routine whose name starts with @var{prefix} as the main
+routine for the debugger.
+
+@item -mmalloc64
+@opindex mmalloc64
+Default to 64-bit memory allocation routines.
+
+@item -mpointer-size=@var{size}
+@opindex -mpointer-size=@var{size}
+Set the default size of pointers. Possible options for @var{size} are
+@samp{32} or @samp{short} for 32 bit pointers, @samp{64} or @samp{long}
+for 64 bit pointers, and @samp{no} for supporting only 32 bit pointers.
+The later option disables @code{pragma pointer_size}.
+@end table
+
+@node VxWorks Options
+@subsection VxWorks Options
+@cindex VxWorks Options
+
+The options in this section are defined for all VxWorks targets.
+Options specific to the target hardware are listed with the other
+options for that target.
+
+@table @gcctabopt
+@item -mrtp
+@opindex mrtp
+GCC can generate code for both VxWorks kernels and real time processes
+(RTPs).  This option switches from the former to the latter.  It also
+defines the preprocessor macro @code{__RTP__}.
+
+@item -non-static
+@opindex non-static
+Link an RTP executable against shared libraries rather than static
+libraries.  The options @option{-static} and @option{-shared} can
+also be used for RTPs (@pxref{Link Options}); @option{-static}
+is the default.
+
+@item -Bstatic
+@itemx -Bdynamic
+@opindex Bstatic
+@opindex Bdynamic
+These options are passed down to the linker.  They are defined for
+compatibility with Diab.
+
+@item -Xbind-lazy
+@opindex Xbind-lazy
+Enable lazy binding of function calls.  This option is equivalent to
+@option{-Wl,-z,now} and is defined for compatibility with Diab.
+
+@item -Xbind-now
+@opindex Xbind-now
+Disable lazy binding of function calls.  This option is the default and
+is defined for compatibility with Diab.
+@end table
+
+@node x86-64 Options
+@subsection x86-64 Options
+@cindex x86-64 options
+
+These are listed under @xref{i386 and x86-64 Options}.
+
+@node Xstormy16 Options
+@subsection Xstormy16 Options
+@cindex Xstormy16 Options
+
+These options are defined for Xstormy16:
+
+@table @gcctabopt
+@item -msim
+@opindex msim
+Choose startup files and linker script suitable for the simulator.
+@end table
+
+@node Xtensa Options
+@subsection Xtensa Options
+@cindex Xtensa Options
+
+These options are supported for Xtensa targets:
+
+@table @gcctabopt
+@item -mconst16
+@itemx -mno-const16
+@opindex mconst16
+@opindex mno-const16
+Enable or disable use of @code{CONST16} instructions for loading
+constant values.  The @code{CONST16} instruction is currently not a
+standard option from Tensilica.  When enabled, @code{CONST16}
+instructions are always used in place of the standard @code{L32R}
+instructions.  The use of @code{CONST16} is enabled by default only if
+the @code{L32R} instruction is not available.
+
+@item -mfused-madd
+@itemx -mno-fused-madd
+@opindex mfused-madd
+@opindex mno-fused-madd
+Enable or disable use of fused multiply/add and multiply/subtract
+instructions in the floating-point option.  This has no effect if the
+floating-point option is not also enabled.  Disabling fused multiply/add
+and multiply/subtract instructions forces the compiler to use separate
+instructions for the multiply and add/subtract operations.  This may be
+desirable in some cases where strict IEEE 754-compliant results are
+required: the fused multiply add/subtract instructions do not round the
+intermediate result, thereby producing results with @emph{more} bits of
+precision than specified by the IEEE standard.  Disabling fused multiply
+add/subtract instructions also ensures that the program output is not
+sensitive to the compiler's ability to combine multiply and add/subtract
+operations.
+
+@item -mserialize-volatile
+@itemx -mno-serialize-volatile
+@opindex mserialize-volatile
+@opindex mno-serialize-volatile
+When this option is enabled, GCC inserts @code{MEMW} instructions before
+@code{volatile} memory references to guarantee sequential consistency.
+The default is @option{-mserialize-volatile}.  Use
+@option{-mno-serialize-volatile} to omit the @code{MEMW} instructions.
+
+@item -mforce-no-pic
+@opindex mforce-no-pic
+For targets, like GNU/Linux, where all user-mode Xtensa code must be
+position-independent code (PIC), this option disables PIC for compiling
+kernel code.
+
+@item -mtext-section-literals
+@itemx -mno-text-section-literals
+@opindex mtext-section-literals
+@opindex mno-text-section-literals
+Control the treatment of literal pools.  The default is
+@option{-mno-text-section-literals}, which places literals in a separate
+section in the output file.  This allows the literal pool to be placed
+in a data RAM/ROM, and it also allows the linker to combine literal
+pools from separate object files to remove redundant literals and
+improve code size.  With @option{-mtext-section-literals}, the literals
+are interspersed in the text section in order to keep them as close as
+possible to their references.  This may be necessary for large assembly
+files.
+
+@item -mtarget-align
+@itemx -mno-target-align
+@opindex mtarget-align
+@opindex mno-target-align
+When this option is enabled, GCC instructs the assembler to
+automatically align instructions to reduce branch penalties at the
+expense of some code density.  The assembler attempts to widen density
+instructions to align branch targets and the instructions following call
+instructions.  If there are not enough preceding safe density
+instructions to align a target, no widening is performed.  The
+default is @option{-mtarget-align}.  These options do not affect the
+treatment of auto-aligned instructions like @code{LOOP}, which the
+assembler always aligns, either by widening density instructions or
+by inserting NOP instructions.
+
+@item -mlongcalls
+@itemx -mno-longcalls
+@opindex mlongcalls
+@opindex mno-longcalls
+When this option is enabled, GCC instructs the assembler to translate
+direct calls to indirect calls unless it can determine that the target
+of a direct call is in the range allowed by the call instruction.  This
+translation typically occurs for calls to functions in other source
+files.  Specifically, the assembler translates a direct @code{CALL}
+instruction into an @code{L32R} followed by a @code{CALLX} instruction.
+The default is @option{-mno-longcalls}.  This option should be used in
+programs where the call target can potentially be out of range.  This
+option is implemented in the assembler, not the compiler, so the
+assembly code generated by GCC still shows direct call
+instructions---look at the disassembled object code to see the actual
+instructions.  Note that the assembler uses an indirect call for
+every cross-file call, not just those that really are out of range.
+@end table
+
+@node zSeries Options
+@subsection zSeries Options
+@cindex zSeries options
+
+These are listed under @xref{S/390 and zSeries Options}.
+
+@node Code Gen Options
+@section Options for Code Generation Conventions
+@cindex code generation conventions
+@cindex options, code generation
+@cindex run-time options
+
+These machine-independent options control the interface conventions
+used in code generation.
+
+Most of them have both positive and negative forms; the negative form
+of @option{-ffoo} is @option{-fno-foo}.  In the table below, only
+one of the forms is listed---the one that is not the default.  You
+can figure out the other form by either removing @samp{no-} or adding
+it.
+
+@table @gcctabopt
+@item -fbounds-check
+@opindex fbounds-check
+For front ends that support it, generate additional code to check that
+indices used to access arrays are within the declared range.  This is
+currently only supported by the Java and Fortran front ends, where
+this option defaults to true and false respectively.
+
+@item -fstack-reuse=@var{reuse-level}
+@opindex fstack_reuse
+This option controls stack space reuse for user declared local/auto variables
+and compiler generated temporaries.  @var{reuse_level} can be @samp{all},
+@samp{named_vars}, or @samp{none}. @samp{all} enables stack reuse for all
+local variables and temporaries, @samp{named_vars} enables the reuse only for
+user defined local variables with names, and @samp{none} disables stack reuse
+completely. The default value is @samp{all}. The option is needed when the
+program extends the lifetime of a scoped local variable or a compiler generated
+temporary beyond the end point defined by the language.  When a lifetime of
+a variable ends, and if the variable lives in memory, the optimizing compiler
+has the freedom to reuse its stack space with other temporaries or scoped
+local variables whose live range does not overlap with it. Legacy code extending
+local lifetime will likely to break with the stack reuse optimization.
+
+For example,
+
+@smallexample
+   int *p;
+   @{
+     int local1;
+
+     p = &local1;
+     local1 = 10;
+     ....
+   @}
+   @{
+      int local2;
+      local2 = 20;
+      ...
+   @}
+
+   if (*p == 10)  // out of scope use of local1
+     @{
+
+     @}
+@end smallexample
+
+Another example:
+@smallexample
+
+   struct A
+   @{
+       A(int k) : i(k), j(k) @{ @}
+       int i;
+       int j;
+   @};
+
+   A *ap;
+
+   void foo(const A& ar)
+   @{
+      ap = &ar;
+   @}
+
+   void bar()
+   @{
+      foo(A(10)); // temp object's lifetime ends when foo returns
+
+      @{
+        A a(20);
+        ....
+      @}
+      ap->i+= 10;  // ap references out of scope temp whose space
+                   // is reused with a. What is the value of ap->i?
+   @}
+
+@end smallexample
+
+The lifetime of a compiler generated temporary is well defined by the C++
+standard. When a lifetime of a temporary ends, and if the temporary lives
+in memory, the optimizing compiler has the freedom to reuse its stack
+space with other temporaries or scoped local variables whose live range
+does not overlap with it. However some of the legacy code relies on
+the behavior of older compilers in which temporaries' stack space is
+not reused, the aggressive stack reuse can lead to runtime errors. This
+option is used to control the temporary stack reuse optimization.
+
+@item -ftrapv
+@opindex ftrapv
+This option generates traps for signed overflow on addition, subtraction,
+multiplication operations.
+
+@item -fwrapv
+@opindex fwrapv
+This option instructs the compiler to assume that signed arithmetic
+overflow of addition, subtraction and multiplication wraps around
+using twos-complement representation.  This flag enables some optimizations
+and disables others.  This option is enabled by default for the Java
+front end, as required by the Java language specification.
+
+@item -fexceptions
+@opindex fexceptions
+Enable exception handling.  Generates extra code needed to propagate
+exceptions.  For some targets, this implies GCC generates frame
+unwind information for all functions, which can produce significant data
+size overhead, although it does not affect execution.  If you do not
+specify this option, GCC enables it by default for languages like
+C++ that normally require exception handling, and disables it for
+languages like C that do not normally require it.  However, you may need
+to enable this option when compiling C code that needs to interoperate
+properly with exception handlers written in C++.  You may also wish to
+disable this option if you are compiling older C++ programs that don't
+use exception handling.
+
+@item -fnon-call-exceptions
+@opindex fnon-call-exceptions
+Generate code that allows trapping instructions to throw exceptions.
+Note that this requires platform-specific runtime support that does
+not exist everywhere.  Moreover, it only allows @emph{trapping}
+instructions to throw exceptions, i.e.@: memory references or floating-point
+instructions.  It does not allow exceptions to be thrown from
+arbitrary signal handlers such as @code{SIGALRM}.
+
+@item -fdelete-dead-exceptions
+@opindex fdelete-dead-exceptions
+Consider that instructions that may throw exceptions but don't otherwise
+contribute to the execution of the program can be optimized away.
+This option is enabled by default for the Ada front end, as permitted by
+the Ada language specification.
+Optimization passes that cause dead exceptions to be removed are enabled independently at different optimization levels.
+
+@item -funwind-tables
+@opindex funwind-tables
+Similar to @option{-fexceptions}, except that it just generates any needed
+static data, but does not affect the generated code in any other way.
+You normally do not need to enable this option; instead, a language processor
+that needs this handling enables it on your behalf.
+
+@item -fasynchronous-unwind-tables
+@opindex fasynchronous-unwind-tables
+Generate unwind table in DWARF 2 format, if supported by target machine.  The
+table is exact at each instruction boundary, so it can be used for stack
+unwinding from asynchronous events (such as debugger or garbage collector).
+
+@item -fpcc-struct-return
+@opindex fpcc-struct-return
+Return ``short'' @code{struct} and @code{union} values in memory like
+longer ones, rather than in registers.  This convention is less
+efficient, but it has the advantage of allowing intercallability between
+GCC-compiled files and files compiled with other compilers, particularly
+the Portable C Compiler (pcc).
+
+The precise convention for returning structures in memory depends
+on the target configuration macros.
+
+Short structures and unions are those whose size and alignment match
+that of some integer type.
+
+@strong{Warning:} code compiled with the @option{-fpcc-struct-return}
+switch is not binary compatible with code compiled with the
+@option{-freg-struct-return} switch.
+Use it to conform to a non-default application binary interface.
+
+@item -freg-struct-return
+@opindex freg-struct-return
+Return @code{struct} and @code{union} values in registers when possible.
+This is more efficient for small structures than
+@option{-fpcc-struct-return}.
+
+If you specify neither @option{-fpcc-struct-return} nor
+@option{-freg-struct-return}, GCC defaults to whichever convention is
+standard for the target.  If there is no standard convention, GCC
+defaults to @option{-fpcc-struct-return}, except on targets where GCC is
+the principal compiler.  In those cases, we can choose the standard, and
+we chose the more efficient register return alternative.
+
+@strong{Warning:} code compiled with the @option{-freg-struct-return}
+switch is not binary compatible with code compiled with the
+@option{-fpcc-struct-return} switch.
+Use it to conform to a non-default application binary interface.
+
+@item -fshort-enums
+@opindex fshort-enums
+Allocate to an @code{enum} type only as many bytes as it needs for the
+declared range of possible values.  Specifically, the @code{enum} type
+is equivalent to the smallest integer type that has enough room.
+
+@strong{Warning:} the @option{-fshort-enums} switch causes GCC to generate
+code that is not binary compatible with code generated without that switch.
+Use it to conform to a non-default application binary interface.
+
+@item -fshort-double
+@opindex fshort-double
+Use the same size for @code{double} as for @code{float}.
+
+@strong{Warning:} the @option{-fshort-double} switch causes GCC to generate
+code that is not binary compatible with code generated without that switch.
+Use it to conform to a non-default application binary interface.
+
+@item -fshort-wchar
+@opindex fshort-wchar
+Override the underlying type for @samp{wchar_t} to be @samp{short
+unsigned int} instead of the default for the target.  This option is
+useful for building programs to run under WINE@.
+
+@strong{Warning:} the @option{-fshort-wchar} switch causes GCC to generate
+code that is not binary compatible with code generated without that switch.
+Use it to conform to a non-default application binary interface.
+
+@item -fno-common
+@opindex fno-common
+In C code, controls the placement of uninitialized global variables.
+Unix C compilers have traditionally permitted multiple definitions of
+such variables in different compilation units by placing the variables
+in a common block.
+This is the behavior specified by @option{-fcommon}, and is the default
+for GCC on most targets.
+On the other hand, this behavior is not required by ISO C, and on some
+targets may carry a speed or code size penalty on variable references.
+The @option{-fno-common} option specifies that the compiler should place
+uninitialized global variables in the data section of the object file,
+rather than generating them as common blocks.
+This has the effect that if the same variable is declared
+(without @code{extern}) in two different compilations,
+you get a multiple-definition error when you link them.
+In this case, you must compile with @option{-fcommon} instead.
+Compiling with @option{-fno-common} is useful on targets for which
+it provides better performance, or if you wish to verify that the
+program will work on other systems that always treat uninitialized
+variable declarations this way.
+
+@item -fno-ident
+@opindex fno-ident
+Ignore the @samp{#ident} directive.
+
+@item -finhibit-size-directive
+@opindex finhibit-size-directive
+Don't output a @code{.size} assembler directive, or anything else that
+would cause trouble if the function is split in the middle, and the
+two halves are placed at locations far apart in memory.  This option is
+used when compiling @file{crtstuff.c}; you should not need to use it
+for anything else.
+
+@item -fverbose-asm
+@opindex fverbose-asm
+Put extra commentary information in the generated assembly code to
+make it more readable.  This option is generally only of use to those
+who actually need to read the generated assembly code (perhaps while
+debugging the compiler itself).
+
+@option{-fno-verbose-asm}, the default, causes the
+extra information to be omitted and is useful when comparing two assembler
+files.
+
+@item -frecord-gcc-switches
+@opindex frecord-gcc-switches
+This switch causes the command line used to invoke the
+compiler to be recorded into the object file that is being created.
+This switch is only implemented on some targets and the exact format
+of the recording is target and binary file format dependent, but it
+usually takes the form of a section containing ASCII text.  This
+switch is related to the @option{-fverbose-asm} switch, but that
+switch only records information in the assembler output file as
+comments, so it never reaches the object file.
+See also @option{-grecord-gcc-switches} for another
+way of storing compiler options into the object file.
+
+@item -fpic
+@opindex fpic
+@cindex global offset table
+@cindex PIC
+Generate position-independent code (PIC) suitable for use in a shared
+library, if supported for the target machine.  Such code accesses all
+constant addresses through a global offset table (GOT)@.  The dynamic
+loader resolves the GOT entries when the program starts (the dynamic
+loader is not part of GCC; it is part of the operating system).  If
+the GOT size for the linked executable exceeds a machine-specific
+maximum size, you get an error message from the linker indicating that
+@option{-fpic} does not work; in that case, recompile with @option{-fPIC}
+instead.  (These maximums are 8k on the SPARC and 32k
+on the m68k and RS/6000.  The 386 has no such limit.)
+
+Position-independent code requires special support, and therefore works
+only on certain machines.  For the 386, GCC supports PIC for System V
+but not for the Sun 386i.  Code generated for the IBM RS/6000 is always
+position-independent.
+
+When this flag is set, the macros @code{__pic__} and @code{__PIC__}
+are defined to 1.
+
+@item -fPIC
+@opindex fPIC
+If supported for the target machine, emit position-independent code,
+suitable for dynamic linking and avoiding any limit on the size of the
+global offset table.  This option makes a difference on the m68k,
+PowerPC and SPARC@.
+
+Position-independent code requires special support, and therefore works
+only on certain machines.
+
+When this flag is set, the macros @code{__pic__} and @code{__PIC__}
+are defined to 2.
+
+@item -fpie
+@itemx -fPIE
+@opindex fpie
+@opindex fPIE
+These options are similar to @option{-fpic} and @option{-fPIC}, but
+generated position independent code can be only linked into executables.
+Usually these options are used when @option{-pie} GCC option is
+used during linking.
+
+@option{-fpie} and @option{-fPIE} both define the macros
+@code{__pie__} and @code{__PIE__}.  The macros have the value 1
+for @option{-fpie} and 2 for @option{-fPIE}.
+
+@item -fno-jump-tables
+@opindex fno-jump-tables
+Do not use jump tables for switch statements even where it would be
+more efficient than other code generation strategies.  This option is
+of use in conjunction with @option{-fpic} or @option{-fPIC} for
+building code that forms part of a dynamic linker and cannot
+reference the address of a jump table.  On some targets, jump tables
+do not require a GOT and this option is not needed.
+
+@item -ffixed-@var{reg}
+@opindex ffixed
+Treat the register named @var{reg} as a fixed register; generated code
+should never refer to it (except perhaps as a stack pointer, frame
+pointer or in some other fixed role).
+
+@var{reg} must be the name of a register.  The register names accepted
+are machine-specific and are defined in the @code{REGISTER_NAMES}
+macro in the machine description macro file.
+
+This flag does not have a negative form, because it specifies a
+three-way choice.
+
+@item -fcall-used-@var{reg}
+@opindex fcall-used
+Treat the register named @var{reg} as an allocable register that is
+clobbered by function calls.  It may be allocated for temporaries or
+variables that do not live across a call.  Functions compiled this way
+do not save and restore the register @var{reg}.
+
+It is an error to use this flag with the frame pointer or stack pointer.
+Use of this flag for other registers that have fixed pervasive roles in
+the machine's execution model produces disastrous results.
+
+This flag does not have a negative form, because it specifies a
+three-way choice.
+
+@item -fcall-saved-@var{reg}
+@opindex fcall-saved
+Treat the register named @var{reg} as an allocable register saved by
+functions.  It may be allocated even for temporaries or variables that
+live across a call.  Functions compiled this way save and restore
+the register @var{reg} if they use it.
+
+It is an error to use this flag with the frame pointer or stack pointer.
+Use of this flag for other registers that have fixed pervasive roles in
+the machine's execution model produces disastrous results.
+
+A different sort of disaster results from the use of this flag for
+a register in which function values may be returned.
+
+This flag does not have a negative form, because it specifies a
+three-way choice.
+
+@item -fpack-struct[=@var{n}]
+@opindex fpack-struct
+Without a value specified, pack all structure members together without
+holes.  When a value is specified (which must be a small power of two), pack
+structure members according to this value, representing the maximum
+alignment (that is, objects with default alignment requirements larger than
+this are output potentially unaligned at the next fitting location.
+
+@strong{Warning:} the @option{-fpack-struct} switch causes GCC to generate
+code that is not binary compatible with code generated without that switch.
+Additionally, it makes the code suboptimal.
+Use it to conform to a non-default application binary interface.
+
+@item -finstrument-functions
+@opindex finstrument-functions
+Generate instrumentation calls for entry and exit to functions.  Just
+after function entry and just before function exit, the following
+profiling functions are called with the address of the current
+function and its call site.  (On some platforms,
+@code{__builtin_return_address} does not work beyond the current
+function, so the call site information may not be available to the
+profiling functions otherwise.)
+
+@smallexample
+void __cyg_profile_func_enter (void *this_fn,
+                               void *call_site);
+void __cyg_profile_func_exit  (void *this_fn,
+                               void *call_site);
+@end smallexample
+
+The first argument is the address of the start of the current function,
+which may be looked up exactly in the symbol table.
+
+This instrumentation is also done for functions expanded inline in other
+functions.  The profiling calls indicate where, conceptually, the
+inline function is entered and exited.  This means that addressable
+versions of such functions must be available.  If all your uses of a
+function are expanded inline, this may mean an additional expansion of
+code size.  If you use @samp{extern inline} in your C code, an
+addressable version of such functions must be provided.  (This is
+normally the case anyway, but if you get lucky and the optimizer always
+expands the functions inline, you might have gotten away without
+providing static copies.)
+
+A function may be given the attribute @code{no_instrument_function}, in
+which case this instrumentation is not done.  This can be used, for
+example, for the profiling functions listed above, high-priority
+interrupt routines, and any functions from which the profiling functions
+cannot safely be called (perhaps signal handlers, if the profiling
+routines generate output or allocate memory).
+
+@item -finstrument-functions-exclude-file-list=@var{file},@var{file},@dots{}
+@opindex finstrument-functions-exclude-file-list
+
+Set the list of functions that are excluded from instrumentation (see
+the description of @code{-finstrument-functions}).  If the file that
+contains a function definition matches with one of @var{file}, then
+that function is not instrumented.  The match is done on substrings:
+if the @var{file} parameter is a substring of the file name, it is
+considered to be a match.
+
+For example:
+
+@smallexample
+-finstrument-functions-exclude-file-list=/bits/stl,include/sys
+@end smallexample
+
+@noindent
+excludes any inline function defined in files whose pathnames
+contain @code{/bits/stl} or @code{include/sys}.
+
+If, for some reason, you want to include letter @code{','} in one of
+@var{sym}, write @code{'\,'}. For example,
+@code{-finstrument-functions-exclude-file-list='\,\,tmp'}
+(note the single quote surrounding the option).
+
+@item -finstrument-functions-exclude-function-list=@var{sym},@var{sym},@dots{}
+@opindex finstrument-functions-exclude-function-list
+
+This is similar to @code{-finstrument-functions-exclude-file-list},
+but this option sets the list of function names to be excluded from
+instrumentation.  The function name to be matched is its user-visible
+name, such as @code{vector<int> blah(const vector<int> &)}, not the
+internal mangled name (e.g., @code{_Z4blahRSt6vectorIiSaIiEE}).  The
+match is done on substrings: if the @var{sym} parameter is a substring
+of the function name, it is considered to be a match.  For C99 and C++
+extended identifiers, the function name must be given in UTF-8, not
+using universal character names.
+
+@item -fstack-check
+@opindex fstack-check
+Generate code to verify that you do not go beyond the boundary of the
+stack.  You should specify this flag if you are running in an
+environment with multiple threads, but you only rarely need to specify it in
+a single-threaded environment since stack overflow is automatically
+detected on nearly all systems if there is only one stack.
+
+Note that this switch does not actually cause checking to be done; the
+operating system or the language runtime must do that.  The switch causes
+generation of code to ensure that they see the stack being extended.
+
+You can additionally specify a string parameter: @code{no} means no
+checking, @code{generic} means force the use of old-style checking,
+@code{specific} means use the best checking method and is equivalent
+to bare @option{-fstack-check}.
+
+Old-style checking is a generic mechanism that requires no specific
+target support in the compiler but comes with the following drawbacks:
+
+@enumerate
+@item
+Modified allocation strategy for large objects: they are always
+allocated dynamically if their size exceeds a fixed threshold.
+
+@item
+Fixed limit on the size of the static frame of functions: when it is
+topped by a particular function, stack checking is not reliable and
+a warning is issued by the compiler.
+
+@item
+Inefficiency: because of both the modified allocation strategy and the
+generic implementation, code performance is hampered.
+@end enumerate
+
+Note that old-style stack checking is also the fallback method for
+@code{specific} if no target support has been added in the compiler.
+
+@item -fstack-limit-register=@var{reg}
+@itemx -fstack-limit-symbol=@var{sym}
+@itemx -fno-stack-limit
+@opindex fstack-limit-register
+@opindex fstack-limit-symbol
+@opindex fno-stack-limit
+Generate code to ensure that the stack does not grow beyond a certain value,
+either the value of a register or the address of a symbol.  If a larger
+stack is required, a signal is raised at run time.  For most targets,
+the signal is raised before the stack overruns the boundary, so
+it is possible to catch the signal without taking special precautions.
+
+For instance, if the stack starts at absolute address @samp{0x80000000}
+and grows downwards, you can use the flags
+@option{-fstack-limit-symbol=__stack_limit} and
+@option{-Wl,--defsym,__stack_limit=0x7ffe0000} to enforce a stack limit
+of 128KB@.  Note that this may only work with the GNU linker.
+
+@item -fsplit-stack
+@opindex fsplit-stack
+Generate code to automatically split the stack before it overflows.
+The resulting program has a discontiguous stack which can only
+overflow if the program is unable to allocate any more memory.  This
+is most useful when running threaded programs, as it is no longer
+necessary to calculate a good stack size to use for each thread.  This
+is currently only implemented for the i386 and x86_64 back ends running
+GNU/Linux.
+
+When code compiled with @option{-fsplit-stack} calls code compiled
+without @option{-fsplit-stack}, there may not be much stack space
+available for the latter code to run.  If compiling all code,
+including library code, with @option{-fsplit-stack} is not an option,
+then the linker can fix up these calls so that the code compiled
+without @option{-fsplit-stack} always has a large stack.  Support for
+this is implemented in the gold linker in GNU binutils release 2.21
+and later.
+
+@item -fleading-underscore
+@opindex fleading-underscore
+This option and its counterpart, @option{-fno-leading-underscore}, forcibly
+change the way C symbols are represented in the object file.  One use
+is to help link with legacy assembly code.
+
+@strong{Warning:} the @option{-fleading-underscore} switch causes GCC to
+generate code that is not binary compatible with code generated without that
+switch.  Use it to conform to a non-default application binary interface.
+Not all targets provide complete support for this switch.
+
+@item -ftls-model=@var{model}
+@opindex ftls-model
+Alter the thread-local storage model to be used (@pxref{Thread-Local}).
+The @var{model} argument should be one of @code{global-dynamic},
+@code{local-dynamic}, @code{initial-exec} or @code{local-exec}.
+
+The default without @option{-fpic} is @code{initial-exec}; with
+@option{-fpic} the default is @code{global-dynamic}.
+
+@item -fvisibility=@var{default|internal|hidden|protected}
+@opindex fvisibility
+Set the default ELF image symbol visibility to the specified option---all
+symbols are marked with this unless overridden within the code.
+Using this feature can very substantially improve linking and
+load times of shared object libraries, produce more optimized
+code, provide near-perfect API export and prevent symbol clashes.
+It is @strong{strongly} recommended that you use this in any shared objects
+you distribute.
+
+Despite the nomenclature, @code{default} always means public; i.e.,
+available to be linked against from outside the shared object.
+@code{protected} and @code{internal} are pretty useless in real-world
+usage so the only other commonly used option is @code{hidden}.
+The default if @option{-fvisibility} isn't specified is
+@code{default}, i.e., make every
+symbol public---this causes the same behavior as previous versions of
+GCC@.
+
+A good explanation of the benefits offered by ensuring ELF
+symbols have the correct visibility is given by ``How To Write
+Shared Libraries'' by Ulrich Drepper (which can be found at
+@w{@uref{http://people.redhat.com/~drepper/}})---however a superior
+solution made possible by this option to marking things hidden when
+the default is public is to make the default hidden and mark things
+public.  This is the norm with DLLs on Windows and with @option{-fvisibility=hidden}
+and @code{__attribute__ ((visibility("default")))} instead of
+@code{__declspec(dllexport)} you get almost identical semantics with
+identical syntax.  This is a great boon to those working with
+cross-platform projects.
+
+For those adding visibility support to existing code, you may find
+@samp{#pragma GCC visibility} of use.  This works by you enclosing
+the declarations you wish to set visibility for with (for example)
+@samp{#pragma GCC visibility push(hidden)} and
+@samp{#pragma GCC visibility pop}.
+Bear in mind that symbol visibility should be viewed @strong{as
+part of the API interface contract} and thus all new code should
+always specify visibility when it is not the default; i.e., declarations
+only for use within the local DSO should @strong{always} be marked explicitly
+as hidden as so to avoid PLT indirection overheads---making this
+abundantly clear also aids readability and self-documentation of the code.
+Note that due to ISO C++ specification requirements, @code{operator new} and
+@code{operator delete} must always be of default visibility.
+
+Be aware that headers from outside your project, in particular system
+headers and headers from any other library you use, may not be
+expecting to be compiled with visibility other than the default.  You
+may need to explicitly say @samp{#pragma GCC visibility push(default)}
+before including any such headers.
+
+@samp{extern} declarations are not affected by @option{-fvisibility}, so
+a lot of code can be recompiled with @option{-fvisibility=hidden} with
+no modifications.  However, this means that calls to @code{extern}
+functions with no explicit visibility use the PLT, so it is more
+effective to use @code{__attribute ((visibility))} and/or
+@code{#pragma GCC visibility} to tell the compiler which @code{extern}
+declarations should be treated as hidden.
+
+Note that @option{-fvisibility} does affect C++ vague linkage
+entities. This means that, for instance, an exception class that is
+be thrown between DSOs must be explicitly marked with default
+visibility so that the @samp{type_info} nodes are unified between
+the DSOs.
+
+An overview of these techniques, their benefits and how to use them
+is at @uref{http://gcc.gnu.org/@/wiki/@/Visibility}.
+
+@item -fstrict-volatile-bitfields
+@opindex fstrict-volatile-bitfields
+This option should be used if accesses to volatile bit-fields (or other
+structure fields, although the compiler usually honors those types
+anyway) should use a single access of the width of the
+field's type, aligned to a natural alignment if possible.  For
+example, targets with memory-mapped peripheral registers might require
+all such accesses to be 16 bits wide; with this flag you can
+declare all peripheral bit-fields as @code{unsigned short} (assuming short
+is 16 bits on these targets) to force GCC to use 16-bit accesses
+instead of, perhaps, a more efficient 32-bit access.
+
+If this option is disabled, the compiler uses the most efficient
+instruction.  In the previous example, that might be a 32-bit load
+instruction, even though that accesses bytes that do not contain
+any portion of the bit-field, or memory-mapped registers unrelated to
+the one being updated.
+
+If the target requires strict alignment, and honoring the field
+type would require violating this alignment, a warning is issued.
+If the field has @code{packed} attribute, the access is done without
+honoring the field type.  If the field doesn't have @code{packed}
+attribute, the access is done honoring the field type.  In both cases,
+GCC assumes that the user knows something about the target hardware
+that it is unaware of.
+
+The default value of this option is determined by the application binary
+interface for the target processor.
+
+@item -fsync-libcalls
+@opindex fsync-libcalls
+This option controls whether any out-of-line instance of the @code{__sync}
+family of functions may be used to implement the C++11 @code{__atomic}
+family of functions.
+
+The default value of this option is enabled, thus the only useful form
+of the option is @option{-fno-sync-libcalls}.  This option is used in
+the implementation of the @file{libatomic} runtime library.
+
+@end table
+
+@c man end
+
+@node Environment Variables
+@section Environment Variables Affecting GCC
+@cindex environment variables
+
+@c man begin ENVIRONMENT
+This section describes several environment variables that affect how GCC
+operates.  Some of them work by specifying directories or prefixes to use
+when searching for various kinds of files.  Some are used to specify other
+aspects of the compilation environment.
+
+Note that you can also specify places to search using options such as
+@option{-B}, @option{-I} and @option{-L} (@pxref{Directory Options}).  These
+take precedence over places specified using environment variables, which
+in turn take precedence over those specified by the configuration of GCC@.
+@xref{Driver,, Controlling the Compilation Driver @file{gcc}, gccint,
+GNU Compiler Collection (GCC) Internals}.
+
+@table @env
+@item LANG
+@itemx LC_CTYPE
+@c @itemx LC_COLLATE
+@itemx LC_MESSAGES
+@c @itemx LC_MONETARY
+@c @itemx LC_NUMERIC
+@c @itemx LC_TIME
+@itemx LC_ALL
+@findex LANG
+@findex LC_CTYPE
+@c @findex LC_COLLATE
+@findex LC_MESSAGES
+@c @findex LC_MONETARY
+@c @findex LC_NUMERIC
+@c @findex LC_TIME
+@findex LC_ALL
+@cindex locale
+These environment variables control the way that GCC uses
+localization information which allows GCC to work with different
+national conventions.  GCC inspects the locale categories
+@env{LC_CTYPE} and @env{LC_MESSAGES} if it has been configured to do
+so.  These locale categories can be set to any value supported by your
+installation.  A typical value is @samp{en_GB.UTF-8} for English in the United
+Kingdom encoded in UTF-8.
+
+The @env{LC_CTYPE} environment variable specifies character
+classification.  GCC uses it to determine the character boundaries in
+a string; this is needed for some multibyte encodings that contain quote
+and escape characters that are otherwise interpreted as a string
+end or escape.
+
+The @env{LC_MESSAGES} environment variable specifies the language to
+use in diagnostic messages.
+
+If the @env{LC_ALL} environment variable is set, it overrides the value
+of @env{LC_CTYPE} and @env{LC_MESSAGES}; otherwise, @env{LC_CTYPE}
+and @env{LC_MESSAGES} default to the value of the @env{LANG}
+environment variable.  If none of these variables are set, GCC
+defaults to traditional C English behavior.
+
+@item TMPDIR
+@findex TMPDIR
+If @env{TMPDIR} is set, it specifies the directory to use for temporary
+files.  GCC uses temporary files to hold the output of one stage of
+compilation which is to be used as input to the next stage: for example,
+the output of the preprocessor, which is the input to the compiler
+proper.
+
+@item GCC_COMPARE_DEBUG
+@findex GCC_COMPARE_DEBUG
+Setting @env{GCC_COMPARE_DEBUG} is nearly equivalent to passing
+@option{-fcompare-debug} to the compiler driver.  See the documentation
+of this option for more details.
+
+@item GCC_EXEC_PREFIX
+@findex GCC_EXEC_PREFIX
+If @env{GCC_EXEC_PREFIX} is set, it specifies a prefix to use in the
+names of the subprograms executed by the compiler.  No slash is added
+when this prefix is combined with the name of a subprogram, but you can
+specify a prefix that ends with a slash if you wish.
+
+If @env{GCC_EXEC_PREFIX} is not set, GCC attempts to figure out
+an appropriate prefix to use based on the pathname it is invoked with.
+
+If GCC cannot find the subprogram using the specified prefix, it
+tries looking in the usual places for the subprogram.
+
+The default value of @env{GCC_EXEC_PREFIX} is
+@file{@var{prefix}/lib/gcc/} where @var{prefix} is the prefix to
+the installed compiler. In many cases @var{prefix} is the value
+of @code{prefix} when you ran the @file{configure} script.
+
+Other prefixes specified with @option{-B} take precedence over this prefix.
+
+This prefix is also used for finding files such as @file{crt0.o} that are
+used for linking.
+
+In addition, the prefix is used in an unusual way in finding the
+directories to search for header files.  For each of the standard
+directories whose name normally begins with @samp{/usr/local/lib/gcc}
+(more precisely, with the value of @env{GCC_INCLUDE_DIR}), GCC tries
+replacing that beginning with the specified prefix to produce an
+alternate directory name.  Thus, with @option{-Bfoo/}, GCC searches
+@file{foo/bar} just before it searches the standard directory 
+@file{/usr/local/lib/bar}.
+If a standard directory begins with the configured
+@var{prefix} then the value of @var{prefix} is replaced by
+@env{GCC_EXEC_PREFIX} when looking for header files.
+
+@item COMPILER_PATH
+@findex COMPILER_PATH
+The value of @env{COMPILER_PATH} is a colon-separated list of
+directories, much like @env{PATH}.  GCC tries the directories thus
+specified when searching for subprograms, if it can't find the
+subprograms using @env{GCC_EXEC_PREFIX}.
+
+@item LIBRARY_PATH
+@findex LIBRARY_PATH
+The value of @env{LIBRARY_PATH} is a colon-separated list of
+directories, much like @env{PATH}.  When configured as a native compiler,
+GCC tries the directories thus specified when searching for special
+linker files, if it can't find them using @env{GCC_EXEC_PREFIX}.  Linking
+using GCC also uses these directories when searching for ordinary
+libraries for the @option{-l} option (but directories specified with
+@option{-L} come first).
+
+@item LANG
+@findex LANG
+@cindex locale definition
+This variable is used to pass locale information to the compiler.  One way in
+which this information is used is to determine the character set to be used
+when character literals, string literals and comments are parsed in C and C++.
+When the compiler is configured to allow multibyte characters,
+the following values for @env{LANG} are recognized:
+
+@table @samp
+@item C-JIS
+Recognize JIS characters.
+@item C-SJIS
+Recognize SJIS characters.
+@item C-EUCJP
+Recognize EUCJP characters.
+@end table
+
+If @env{LANG} is not defined, or if it has some other value, then the
+compiler uses @code{mblen} and @code{mbtowc} as defined by the default locale to
+recognize and translate multibyte characters.
+@end table
+
+@noindent
+Some additional environment variables affect the behavior of the
+preprocessor.
+
+@include cppenv.texi
+
+@c man end
+
+@node Precompiled Headers
+@section Using Precompiled Headers
+@cindex precompiled headers
+@cindex speed of compilation
+
+Often large projects have many header files that are included in every
+source file.  The time the compiler takes to process these header files
+over and over again can account for nearly all of the time required to
+build the project.  To make builds faster, GCC allows you to
+@dfn{precompile} a header file.
+
+To create a precompiled header file, simply compile it as you would any
+other file, if necessary using the @option{-x} option to make the driver
+treat it as a C or C++ header file.  You may want to use a
+tool like @command{make} to keep the precompiled header up-to-date when
+the headers it contains change.
+
+A precompiled header file is searched for when @code{#include} is
+seen in the compilation.  As it searches for the included file
+(@pxref{Search Path,,Search Path,cpp,The C Preprocessor}) the
+compiler looks for a precompiled header in each directory just before it
+looks for the include file in that directory.  The name searched for is
+the name specified in the @code{#include} with @samp{.gch} appended.  If
+the precompiled header file can't be used, it is ignored.
+
+For instance, if you have @code{#include "all.h"}, and you have
+@file{all.h.gch} in the same directory as @file{all.h}, then the
+precompiled header file is used if possible, and the original
+header is used otherwise.
+
+Alternatively, you might decide to put the precompiled header file in a
+directory and use @option{-I} to ensure that directory is searched
+before (or instead of) the directory containing the original header.
+Then, if you want to check that the precompiled header file is always
+used, you can put a file of the same name as the original header in this
+directory containing an @code{#error} command.
+
+This also works with @option{-include}.  So yet another way to use
+precompiled headers, good for projects not designed with precompiled
+header files in mind, is to simply take most of the header files used by
+a project, include them from another header file, precompile that header
+file, and @option{-include} the precompiled header.  If the header files
+have guards against multiple inclusion, they are skipped because
+they've already been included (in the precompiled header).
+
+If you need to precompile the same header file for different
+languages, targets, or compiler options, you can instead make a
+@emph{directory} named like @file{all.h.gch}, and put each precompiled
+header in the directory, perhaps using @option{-o}.  It doesn't matter
+what you call the files in the directory; every precompiled header in
+the directory is considered.  The first precompiled header
+encountered in the directory that is valid for this compilation is
+used; they're searched in no particular order.
+
+There are many other possibilities, limited only by your imagination,
+good sense, and the constraints of your build system.
+
+A precompiled header file can be used only when these conditions apply:
+
+@itemize
+@item
+Only one precompiled header can be used in a particular compilation.
+
+@item
+A precompiled header can't be used once the first C token is seen.  You
+can have preprocessor directives before a precompiled header; you cannot
+include a precompiled header from inside another header.
+
+@item
+The precompiled header file must be produced for the same language as
+the current compilation.  You can't use a C precompiled header for a C++
+compilation.
+
+@item
+The precompiled header file must have been produced by the same compiler
+binary as the current compilation is using.
+
+@item
+Any macros defined before the precompiled header is included must
+either be defined in the same way as when the precompiled header was
+generated, or must not affect the precompiled header, which usually
+means that they don't appear in the precompiled header at all.
+
+The @option{-D} option is one way to define a macro before a
+precompiled header is included; using a @code{#define} can also do it.
+There are also some options that define macros implicitly, like
+@option{-O} and @option{-Wdeprecated}; the same rule applies to macros
+defined this way.
+
+@item If debugging information is output when using the precompiled
+header, using @option{-g} or similar, the same kind of debugging information
+must have been output when building the precompiled header.  However,
+a precompiled header built using @option{-g} can be used in a compilation
+when no debugging information is being output.
+
+@item The same @option{-m} options must generally be used when building
+and using the precompiled header.  @xref{Submodel Options},
+for any cases where this rule is relaxed.
+
+@item Each of the following options must be the same when building and using
+the precompiled header:
+
+@gccoptlist{-fexceptions}
+
+@item
+Some other command-line options starting with @option{-f},
+@option{-p}, or @option{-O} must be defined in the same way as when
+the precompiled header was generated.  At present, it's not clear
+which options are safe to change and which are not; the safest choice
+is to use exactly the same options when generating and using the
+precompiled header.  The following are known to be safe:
+
+@gccoptlist{-fmessage-length=  -fpreprocessed  -fsched-interblock @gol
+-fsched-spec  -fsched-spec-load  -fsched-spec-load-dangerous @gol
+-fsched-verbose=@var{number}  -fschedule-insns  -fvisibility= @gol
+-pedantic-errors}
+
+@end itemize
+
+For all of these except the last, the compiler automatically
+ignores the precompiled header if the conditions aren't met.  If you
+find an option combination that doesn't work and doesn't cause the
+precompiled header to be ignored, please consider filing a bug report,
+see @ref{Bugs}.
+
+If you do use differing options when generating and using the
+precompiled header, the actual behavior is a mixture of the
+behavior for the options.  For instance, if you use @option{-g} to
+generate the precompiled header but not when using it, you may or may
+not get debugging information for routines in the precompiled header.