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Diffstat (limited to 'gcc-4.8.1/gcc/cse.c')
| -rw-r--r-- | gcc-4.8.1/gcc/cse.c | 7596 |
1 files changed, 0 insertions, 7596 deletions
diff --git a/gcc-4.8.1/gcc/cse.c b/gcc-4.8.1/gcc/cse.c deleted file mode 100644 index b200fef4d..000000000 --- a/gcc-4.8.1/gcc/cse.c +++ /dev/null @@ -1,7596 +0,0 @@ -/* Common subexpression elimination for GNU compiler. - Copyright (C) 1987-2013 Free Software Foundation, Inc. - -This file is part of GCC. - -GCC is free software; you can redistribute it and/or modify it under -the terms of the GNU General Public License as published by the Free -Software Foundation; either version 3, or (at your option) any later -version. - -GCC is distributed in the hope that it will be useful, but WITHOUT ANY -WARRANTY; without even the implied warranty of MERCHANTABILITY or -FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -for more details. - -You should have received a copy of the GNU General Public License -along with GCC; see the file COPYING3. If not see -<http://www.gnu.org/licenses/>. */ - -#include "config.h" -#include "system.h" -#include "coretypes.h" -#include "tm.h" -#include "rtl.h" -#include "tm_p.h" -#include "hard-reg-set.h" -#include "regs.h" -#include "basic-block.h" -#include "flags.h" -#include "insn-config.h" -#include "recog.h" -#include "function.h" -#include "expr.h" -#include "diagnostic-core.h" -#include "toplev.h" -#include "ggc.h" -#include "except.h" -#include "target.h" -#include "params.h" -#include "rtlhooks-def.h" -#include "tree-pass.h" -#include "df.h" -#include "dbgcnt.h" -#include "pointer-set.h" - -/* The basic idea of common subexpression elimination is to go - through the code, keeping a record of expressions that would - have the same value at the current scan point, and replacing - expressions encountered with the cheapest equivalent expression. - - It is too complicated to keep track of the different possibilities - when control paths merge in this code; so, at each label, we forget all - that is known and start fresh. This can be described as processing each - extended basic block separately. We have a separate pass to perform - global CSE. - - Note CSE can turn a conditional or computed jump into a nop or - an unconditional jump. When this occurs we arrange to run the jump - optimizer after CSE to delete the unreachable code. - - We use two data structures to record the equivalent expressions: - a hash table for most expressions, and a vector of "quantity - numbers" to record equivalent (pseudo) registers. - - The use of the special data structure for registers is desirable - because it is faster. It is possible because registers references - contain a fairly small number, the register number, taken from - a contiguously allocated series, and two register references are - identical if they have the same number. General expressions - do not have any such thing, so the only way to retrieve the - information recorded on an expression other than a register - is to keep it in a hash table. - -Registers and "quantity numbers": - - At the start of each basic block, all of the (hardware and pseudo) - registers used in the function are given distinct quantity - numbers to indicate their contents. During scan, when the code - copies one register into another, we copy the quantity number. - When a register is loaded in any other way, we allocate a new - quantity number to describe the value generated by this operation. - `REG_QTY (N)' records what quantity register N is currently thought - of as containing. - - All real quantity numbers are greater than or equal to zero. - If register N has not been assigned a quantity, `REG_QTY (N)' will - equal -N - 1, which is always negative. - - Quantity numbers below zero do not exist and none of the `qty_table' - entries should be referenced with a negative index. - - We also maintain a bidirectional chain of registers for each - quantity number. The `qty_table` members `first_reg' and `last_reg', - and `reg_eqv_table' members `next' and `prev' hold these chains. - - The first register in a chain is the one whose lifespan is least local. - Among equals, it is the one that was seen first. - We replace any equivalent register with that one. - - If two registers have the same quantity number, it must be true that - REG expressions with qty_table `mode' must be in the hash table for both - registers and must be in the same class. - - The converse is not true. Since hard registers may be referenced in - any mode, two REG expressions might be equivalent in the hash table - but not have the same quantity number if the quantity number of one - of the registers is not the same mode as those expressions. - -Constants and quantity numbers - - When a quantity has a known constant value, that value is stored - in the appropriate qty_table `const_rtx'. This is in addition to - putting the constant in the hash table as is usual for non-regs. - - Whether a reg or a constant is preferred is determined by the configuration - macro CONST_COSTS and will often depend on the constant value. In any - event, expressions containing constants can be simplified, by fold_rtx. - - When a quantity has a known nearly constant value (such as an address - of a stack slot), that value is stored in the appropriate qty_table - `const_rtx'. - - Integer constants don't have a machine mode. However, cse - determines the intended machine mode from the destination - of the instruction that moves the constant. The machine mode - is recorded in the hash table along with the actual RTL - constant expression so that different modes are kept separate. - -Other expressions: - - To record known equivalences among expressions in general - we use a hash table called `table'. It has a fixed number of buckets - that contain chains of `struct table_elt' elements for expressions. - These chains connect the elements whose expressions have the same - hash codes. - - Other chains through the same elements connect the elements which - currently have equivalent values. - - Register references in an expression are canonicalized before hashing - the expression. This is done using `reg_qty' and qty_table `first_reg'. - The hash code of a register reference is computed using the quantity - number, not the register number. - - When the value of an expression changes, it is necessary to remove from the - hash table not just that expression but all expressions whose values - could be different as a result. - - 1. If the value changing is in memory, except in special cases - ANYTHING referring to memory could be changed. That is because - nobody knows where a pointer does not point. - The function `invalidate_memory' removes what is necessary. - - The special cases are when the address is constant or is - a constant plus a fixed register such as the frame pointer - or a static chain pointer. When such addresses are stored in, - we can tell exactly which other such addresses must be invalidated - due to overlap. `invalidate' does this. - All expressions that refer to non-constant - memory addresses are also invalidated. `invalidate_memory' does this. - - 2. If the value changing is a register, all expressions - containing references to that register, and only those, - must be removed. - - Because searching the entire hash table for expressions that contain - a register is very slow, we try to figure out when it isn't necessary. - Precisely, this is necessary only when expressions have been - entered in the hash table using this register, and then the value has - changed, and then another expression wants to be added to refer to - the register's new value. This sequence of circumstances is rare - within any one basic block. - - `REG_TICK' and `REG_IN_TABLE', accessors for members of - cse_reg_info, are used to detect this case. REG_TICK (i) is - incremented whenever a value is stored in register i. - REG_IN_TABLE (i) holds -1 if no references to register i have been - entered in the table; otherwise, it contains the value REG_TICK (i) - had when the references were entered. If we want to enter a - reference and REG_IN_TABLE (i) != REG_TICK (i), we must scan and - remove old references. Until we want to enter a new entry, the - mere fact that the two vectors don't match makes the entries be - ignored if anyone tries to match them. - - Registers themselves are entered in the hash table as well as in - the equivalent-register chains. However, `REG_TICK' and - `REG_IN_TABLE' do not apply to expressions which are simple - register references. These expressions are removed from the table - immediately when they become invalid, and this can be done even if - we do not immediately search for all the expressions that refer to - the register. - - A CLOBBER rtx in an instruction invalidates its operand for further - reuse. A CLOBBER or SET rtx whose operand is a MEM:BLK - invalidates everything that resides in memory. - -Related expressions: - - Constant expressions that differ only by an additive integer - are called related. When a constant expression is put in - the table, the related expression with no constant term - is also entered. These are made to point at each other - so that it is possible to find out if there exists any - register equivalent to an expression related to a given expression. */ - -/* Length of qty_table vector. We know in advance we will not need - a quantity number this big. */ - -static int max_qty; - -/* Next quantity number to be allocated. - This is 1 + the largest number needed so far. */ - -static int next_qty; - -/* Per-qty information tracking. - - `first_reg' and `last_reg' track the head and tail of the - chain of registers which currently contain this quantity. - - `mode' contains the machine mode of this quantity. - - `const_rtx' holds the rtx of the constant value of this - quantity, if known. A summations of the frame/arg pointer - and a constant can also be entered here. When this holds - a known value, `const_insn' is the insn which stored the - constant value. - - `comparison_{code,const,qty}' are used to track when a - comparison between a quantity and some constant or register has - been passed. In such a case, we know the results of the comparison - in case we see it again. These members record a comparison that - is known to be true. `comparison_code' holds the rtx code of such - a comparison, else it is set to UNKNOWN and the other two - comparison members are undefined. `comparison_const' holds - the constant being compared against, or zero if the comparison - is not against a constant. `comparison_qty' holds the quantity - being compared against when the result is known. If the comparison - is not with a register, `comparison_qty' is -1. */ - -struct qty_table_elem -{ - rtx const_rtx; - rtx const_insn; - rtx comparison_const; - int comparison_qty; - unsigned int first_reg, last_reg; - /* The sizes of these fields should match the sizes of the - code and mode fields of struct rtx_def (see rtl.h). */ - ENUM_BITFIELD(rtx_code) comparison_code : 16; - ENUM_BITFIELD(machine_mode) mode : 8; -}; - -/* The table of all qtys, indexed by qty number. */ -static struct qty_table_elem *qty_table; - -/* Structure used to pass arguments via for_each_rtx to function - cse_change_cc_mode. */ -struct change_cc_mode_args -{ - rtx insn; - rtx newreg; -}; - -#ifdef HAVE_cc0 -/* For machines that have a CC0, we do not record its value in the hash - table since its use is guaranteed to be the insn immediately following - its definition and any other insn is presumed to invalidate it. - - Instead, we store below the current and last value assigned to CC0. - If it should happen to be a constant, it is stored in preference - to the actual assigned value. In case it is a constant, we store - the mode in which the constant should be interpreted. */ - -static rtx this_insn_cc0, prev_insn_cc0; -static enum machine_mode this_insn_cc0_mode, prev_insn_cc0_mode; -#endif - -/* Insn being scanned. */ - -static rtx this_insn; -static bool optimize_this_for_speed_p; - -/* Index by register number, gives the number of the next (or - previous) register in the chain of registers sharing the same - value. - - Or -1 if this register is at the end of the chain. - - If REG_QTY (N) == -N - 1, reg_eqv_table[N].next is undefined. */ - -/* Per-register equivalence chain. */ -struct reg_eqv_elem -{ - int next, prev; -}; - -/* The table of all register equivalence chains. */ -static struct reg_eqv_elem *reg_eqv_table; - -struct cse_reg_info -{ - /* The timestamp at which this register is initialized. */ - unsigned int timestamp; - - /* The quantity number of the register's current contents. */ - int reg_qty; - - /* The number of times the register has been altered in the current - basic block. */ - int reg_tick; - - /* The REG_TICK value at which rtx's containing this register are - valid in the hash table. If this does not equal the current - reg_tick value, such expressions existing in the hash table are - invalid. */ - int reg_in_table; - - /* The SUBREG that was set when REG_TICK was last incremented. Set - to -1 if the last store was to the whole register, not a subreg. */ - unsigned int subreg_ticked; -}; - -/* A table of cse_reg_info indexed by register numbers. */ -static struct cse_reg_info *cse_reg_info_table; - -/* The size of the above table. */ -static unsigned int cse_reg_info_table_size; - -/* The index of the first entry that has not been initialized. */ -static unsigned int cse_reg_info_table_first_uninitialized; - -/* The timestamp at the beginning of the current run of - cse_extended_basic_block. We increment this variable at the beginning of - the current run of cse_extended_basic_block. The timestamp field of a - cse_reg_info entry matches the value of this variable if and only - if the entry has been initialized during the current run of - cse_extended_basic_block. */ -static unsigned int cse_reg_info_timestamp; - -/* A HARD_REG_SET containing all the hard registers for which there is - currently a REG expression in the hash table. Note the difference - from the above variables, which indicate if the REG is mentioned in some - expression in the table. */ - -static HARD_REG_SET hard_regs_in_table; - -/* True if CSE has altered the CFG. */ -static bool cse_cfg_altered; - -/* True if CSE has altered conditional jump insns in such a way - that jump optimization should be redone. */ -static bool cse_jumps_altered; - -/* True if we put a LABEL_REF into the hash table for an INSN - without a REG_LABEL_OPERAND, we have to rerun jump after CSE - to put in the note. */ -static bool recorded_label_ref; - -/* canon_hash stores 1 in do_not_record - if it notices a reference to CC0, PC, or some other volatile - subexpression. */ - -static int do_not_record; - -/* canon_hash stores 1 in hash_arg_in_memory - if it notices a reference to memory within the expression being hashed. */ - -static int hash_arg_in_memory; - -/* The hash table contains buckets which are chains of `struct table_elt's, - each recording one expression's information. - That expression is in the `exp' field. - - The canon_exp field contains a canonical (from the point of view of - alias analysis) version of the `exp' field. - - Those elements with the same hash code are chained in both directions - through the `next_same_hash' and `prev_same_hash' fields. - - Each set of expressions with equivalent values - are on a two-way chain through the `next_same_value' - and `prev_same_value' fields, and all point with - the `first_same_value' field at the first element in - that chain. The chain is in order of increasing cost. - Each element's cost value is in its `cost' field. - - The `in_memory' field is nonzero for elements that - involve any reference to memory. These elements are removed - whenever a write is done to an unidentified location in memory. - To be safe, we assume that a memory address is unidentified unless - the address is either a symbol constant or a constant plus - the frame pointer or argument pointer. - - The `related_value' field is used to connect related expressions - (that differ by adding an integer). - The related expressions are chained in a circular fashion. - `related_value' is zero for expressions for which this - chain is not useful. - - The `cost' field stores the cost of this element's expression. - The `regcost' field stores the value returned by approx_reg_cost for - this element's expression. - - The `is_const' flag is set if the element is a constant (including - a fixed address). - - The `flag' field is used as a temporary during some search routines. - - The `mode' field is usually the same as GET_MODE (`exp'), but - if `exp' is a CONST_INT and has no machine mode then the `mode' - field is the mode it was being used as. Each constant is - recorded separately for each mode it is used with. */ - -struct table_elt -{ - rtx exp; - rtx canon_exp; - struct table_elt *next_same_hash; - struct table_elt *prev_same_hash; - struct table_elt *next_same_value; - struct table_elt *prev_same_value; - struct table_elt *first_same_value; - struct table_elt *related_value; - int cost; - int regcost; - /* The size of this field should match the size - of the mode field of struct rtx_def (see rtl.h). */ - ENUM_BITFIELD(machine_mode) mode : 8; - char in_memory; - char is_const; - char flag; -}; - -/* We don't want a lot of buckets, because we rarely have very many - things stored in the hash table, and a lot of buckets slows - down a lot of loops that happen frequently. */ -#define HASH_SHIFT 5 -#define HASH_SIZE (1 << HASH_SHIFT) -#define HASH_MASK (HASH_SIZE - 1) - -/* Compute hash code of X in mode M. Special-case case where X is a pseudo - register (hard registers may require `do_not_record' to be set). */ - -#define HASH(X, M) \ - ((REG_P (X) && REGNO (X) >= FIRST_PSEUDO_REGISTER \ - ? (((unsigned) REG << 7) + (unsigned) REG_QTY (REGNO (X))) \ - : canon_hash (X, M)) & HASH_MASK) - -/* Like HASH, but without side-effects. */ -#define SAFE_HASH(X, M) \ - ((REG_P (X) && REGNO (X) >= FIRST_PSEUDO_REGISTER \ - ? (((unsigned) REG << 7) + (unsigned) REG_QTY (REGNO (X))) \ - : safe_hash (X, M)) & HASH_MASK) - -/* Determine whether register number N is considered a fixed register for the - purpose of approximating register costs. - It is desirable to replace other regs with fixed regs, to reduce need for - non-fixed hard regs. - A reg wins if it is either the frame pointer or designated as fixed. */ -#define FIXED_REGNO_P(N) \ - ((N) == FRAME_POINTER_REGNUM || (N) == HARD_FRAME_POINTER_REGNUM \ - || fixed_regs[N] || global_regs[N]) - -/* Compute cost of X, as stored in the `cost' field of a table_elt. Fixed - hard registers and pointers into the frame are the cheapest with a cost - of 0. Next come pseudos with a cost of one and other hard registers with - a cost of 2. Aside from these special cases, call `rtx_cost'. */ - -#define CHEAP_REGNO(N) \ - (REGNO_PTR_FRAME_P(N) \ - || (HARD_REGISTER_NUM_P (N) \ - && FIXED_REGNO_P (N) && REGNO_REG_CLASS (N) != NO_REGS)) - -#define COST(X) (REG_P (X) ? 0 : notreg_cost (X, SET, 1)) -#define COST_IN(X, OUTER, OPNO) (REG_P (X) ? 0 : notreg_cost (X, OUTER, OPNO)) - -/* Get the number of times this register has been updated in this - basic block. */ - -#define REG_TICK(N) (get_cse_reg_info (N)->reg_tick) - -/* Get the point at which REG was recorded in the table. */ - -#define REG_IN_TABLE(N) (get_cse_reg_info (N)->reg_in_table) - -/* Get the SUBREG set at the last increment to REG_TICK (-1 if not a - SUBREG). */ - -#define SUBREG_TICKED(N) (get_cse_reg_info (N)->subreg_ticked) - -/* Get the quantity number for REG. */ - -#define REG_QTY(N) (get_cse_reg_info (N)->reg_qty) - -/* Determine if the quantity number for register X represents a valid index - into the qty_table. */ - -#define REGNO_QTY_VALID_P(N) (REG_QTY (N) >= 0) - -/* Compare table_elt X and Y and return true iff X is cheaper than Y. */ - -#define CHEAPER(X, Y) \ - (preferable ((X)->cost, (X)->regcost, (Y)->cost, (Y)->regcost) < 0) - -static struct table_elt *table[HASH_SIZE]; - -/* Chain of `struct table_elt's made so far for this function - but currently removed from the table. */ - -static struct table_elt *free_element_chain; - -/* Set to the cost of a constant pool reference if one was found for a - symbolic constant. If this was found, it means we should try to - convert constants into constant pool entries if they don't fit in - the insn. */ - -static int constant_pool_entries_cost; -static int constant_pool_entries_regcost; - -/* Trace a patch through the CFG. */ - -struct branch_path -{ - /* The basic block for this path entry. */ - basic_block bb; -}; - -/* This data describes a block that will be processed by - cse_extended_basic_block. */ - -struct cse_basic_block_data -{ - /* Total number of SETs in block. */ - int nsets; - /* Size of current branch path, if any. */ - int path_size; - /* Current path, indicating which basic_blocks will be processed. */ - struct branch_path *path; -}; - - -/* Pointers to the live in/live out bitmaps for the boundaries of the - current EBB. */ -static bitmap cse_ebb_live_in, cse_ebb_live_out; - -/* A simple bitmap to track which basic blocks have been visited - already as part of an already processed extended basic block. */ -static sbitmap cse_visited_basic_blocks; - -static bool fixed_base_plus_p (rtx x); -static int notreg_cost (rtx, enum rtx_code, int); -static int approx_reg_cost_1 (rtx *, void *); -static int approx_reg_cost (rtx); -static int preferable (int, int, int, int); -static void new_basic_block (void); -static void make_new_qty (unsigned int, enum machine_mode); -static void make_regs_eqv (unsigned int, unsigned int); -static void delete_reg_equiv (unsigned int); -static int mention_regs (rtx); -static int insert_regs (rtx, struct table_elt *, int); -static void remove_from_table (struct table_elt *, unsigned); -static void remove_pseudo_from_table (rtx, unsigned); -static struct table_elt *lookup (rtx, unsigned, enum machine_mode); -static struct table_elt *lookup_for_remove (rtx, unsigned, enum machine_mode); -static rtx lookup_as_function (rtx, enum rtx_code); -static struct table_elt *insert_with_costs (rtx, struct table_elt *, unsigned, - enum machine_mode, int, int); -static struct table_elt *insert (rtx, struct table_elt *, unsigned, - enum machine_mode); -static void merge_equiv_classes (struct table_elt *, struct table_elt *); -static void invalidate (rtx, enum machine_mode); -static void remove_invalid_refs (unsigned int); -static void remove_invalid_subreg_refs (unsigned int, unsigned int, - enum machine_mode); -static void rehash_using_reg (rtx); -static void invalidate_memory (void); -static void invalidate_for_call (void); -static rtx use_related_value (rtx, struct table_elt *); - -static inline unsigned canon_hash (rtx, enum machine_mode); -static inline unsigned safe_hash (rtx, enum machine_mode); -static inline unsigned hash_rtx_string (const char *); - -static rtx canon_reg (rtx, rtx); -static enum rtx_code find_comparison_args (enum rtx_code, rtx *, rtx *, - enum machine_mode *, - enum machine_mode *); -static rtx fold_rtx (rtx, rtx); -static rtx equiv_constant (rtx); -static void record_jump_equiv (rtx, bool); -static void record_jump_cond (enum rtx_code, enum machine_mode, rtx, rtx, - int); -static void cse_insn (rtx); -static void cse_prescan_path (struct cse_basic_block_data *); -static void invalidate_from_clobbers (rtx); -static void invalidate_from_sets_and_clobbers (rtx); -static rtx cse_process_notes (rtx, rtx, bool *); -static void cse_extended_basic_block (struct cse_basic_block_data *); -static int check_for_label_ref (rtx *, void *); -extern void dump_class (struct table_elt*); -static void get_cse_reg_info_1 (unsigned int regno); -static struct cse_reg_info * get_cse_reg_info (unsigned int regno); -static int check_dependence (rtx *, void *); - -static void flush_hash_table (void); -static bool insn_live_p (rtx, int *); -static bool set_live_p (rtx, rtx, int *); -static int cse_change_cc_mode (rtx *, void *); -static void cse_change_cc_mode_insn (rtx, rtx); -static void cse_change_cc_mode_insns (rtx, rtx, rtx); -static enum machine_mode cse_cc_succs (basic_block, basic_block, rtx, rtx, - bool); - - -#undef RTL_HOOKS_GEN_LOWPART -#define RTL_HOOKS_GEN_LOWPART gen_lowpart_if_possible - -static const struct rtl_hooks cse_rtl_hooks = RTL_HOOKS_INITIALIZER; - -/* Nonzero if X has the form (PLUS frame-pointer integer). */ - -static bool -fixed_base_plus_p (rtx x) -{ - switch (GET_CODE (x)) - { - case REG: - if (x == frame_pointer_rtx || x == hard_frame_pointer_rtx) - return true; - if (x == arg_pointer_rtx && fixed_regs[ARG_POINTER_REGNUM]) - return true; - return false; - - case PLUS: - if (!CONST_INT_P (XEXP (x, 1))) - return false; - return fixed_base_plus_p (XEXP (x, 0)); - - default: - return false; - } -} - -/* Dump the expressions in the equivalence class indicated by CLASSP. - This function is used only for debugging. */ -DEBUG_FUNCTION void -dump_class (struct table_elt *classp) -{ - struct table_elt *elt; - - fprintf (stderr, "Equivalence chain for "); - print_rtl (stderr, classp->exp); - fprintf (stderr, ": \n"); - - for (elt = classp->first_same_value; elt; elt = elt->next_same_value) - { - print_rtl (stderr, elt->exp); - fprintf (stderr, "\n"); - } -} - -/* Subroutine of approx_reg_cost; called through for_each_rtx. */ - -static int -approx_reg_cost_1 (rtx *xp, void *data) -{ - rtx x = *xp; - int *cost_p = (int *) data; - - if (x && REG_P (x)) - { - unsigned int regno = REGNO (x); - - if (! CHEAP_REGNO (regno)) - { - if (regno < FIRST_PSEUDO_REGISTER) - { - if (targetm.small_register_classes_for_mode_p (GET_MODE (x))) - return 1; - *cost_p += 2; - } - else - *cost_p += 1; - } - } - - return 0; -} - -/* Return an estimate of the cost of the registers used in an rtx. - This is mostly the number of different REG expressions in the rtx; - however for some exceptions like fixed registers we use a cost of - 0. If any other hard register reference occurs, return MAX_COST. */ - -static int -approx_reg_cost (rtx x) -{ - int cost = 0; - - if (for_each_rtx (&x, approx_reg_cost_1, (void *) &cost)) - return MAX_COST; - - return cost; -} - -/* Return a negative value if an rtx A, whose costs are given by COST_A - and REGCOST_A, is more desirable than an rtx B. - Return a positive value if A is less desirable, or 0 if the two are - equally good. */ -static int -preferable (int cost_a, int regcost_a, int cost_b, int regcost_b) -{ - /* First, get rid of cases involving expressions that are entirely - unwanted. */ - if (cost_a != cost_b) - { - if (cost_a == MAX_COST) - return 1; - if (cost_b == MAX_COST) - return -1; - } - - /* Avoid extending lifetimes of hardregs. */ - if (regcost_a != regcost_b) - { - if (regcost_a == MAX_COST) - return 1; - if (regcost_b == MAX_COST) - return -1; - } - - /* Normal operation costs take precedence. */ - if (cost_a != cost_b) - return cost_a - cost_b; - /* Only if these are identical consider effects on register pressure. */ - if (regcost_a != regcost_b) - return regcost_a - regcost_b; - return 0; -} - -/* Internal function, to compute cost when X is not a register; called - from COST macro to keep it simple. */ - -static int -notreg_cost (rtx x, enum rtx_code outer, int opno) -{ - return ((GET_CODE (x) == SUBREG - && REG_P (SUBREG_REG (x)) - && GET_MODE_CLASS (GET_MODE (x)) == MODE_INT - && GET_MODE_CLASS (GET_MODE (SUBREG_REG (x))) == MODE_INT - && (GET_MODE_SIZE (GET_MODE (x)) - < GET_MODE_SIZE (GET_MODE (SUBREG_REG (x)))) - && subreg_lowpart_p (x) - && TRULY_NOOP_TRUNCATION_MODES_P (GET_MODE (x), - GET_MODE (SUBREG_REG (x)))) - ? 0 - : rtx_cost (x, outer, opno, optimize_this_for_speed_p) * 2); -} - - -/* Initialize CSE_REG_INFO_TABLE. */ - -static void -init_cse_reg_info (unsigned int nregs) -{ - /* Do we need to grow the table? */ - if (nregs > cse_reg_info_table_size) - { - unsigned int new_size; - - if (cse_reg_info_table_size < 2048) - { - /* Compute a new size that is a power of 2 and no smaller - than the large of NREGS and 64. */ - new_size = (cse_reg_info_table_size - ? cse_reg_info_table_size : 64); - - while (new_size < nregs) - new_size *= 2; - } - else - { - /* If we need a big table, allocate just enough to hold - NREGS registers. */ - new_size = nregs; - } - - /* Reallocate the table with NEW_SIZE entries. */ - free (cse_reg_info_table); - cse_reg_info_table = XNEWVEC (struct cse_reg_info, new_size); - cse_reg_info_table_size = new_size; - cse_reg_info_table_first_uninitialized = 0; - } - - /* Do we have all of the first NREGS entries initialized? */ - if (cse_reg_info_table_first_uninitialized < nregs) - { - unsigned int old_timestamp = cse_reg_info_timestamp - 1; - unsigned int i; - - /* Put the old timestamp on newly allocated entries so that they - will all be considered out of date. We do not touch those - entries beyond the first NREGS entries to be nice to the - virtual memory. */ - for (i = cse_reg_info_table_first_uninitialized; i < nregs; i++) - cse_reg_info_table[i].timestamp = old_timestamp; - - cse_reg_info_table_first_uninitialized = nregs; - } -} - -/* Given REGNO, initialize the cse_reg_info entry for REGNO. */ - -static void -get_cse_reg_info_1 (unsigned int regno) -{ - /* Set TIMESTAMP field to CSE_REG_INFO_TIMESTAMP so that this - entry will be considered to have been initialized. */ - cse_reg_info_table[regno].timestamp = cse_reg_info_timestamp; - - /* Initialize the rest of the entry. */ - cse_reg_info_table[regno].reg_tick = 1; - cse_reg_info_table[regno].reg_in_table = -1; - cse_reg_info_table[regno].subreg_ticked = -1; - cse_reg_info_table[regno].reg_qty = -regno - 1; -} - -/* Find a cse_reg_info entry for REGNO. */ - -static inline struct cse_reg_info * -get_cse_reg_info (unsigned int regno) -{ - struct cse_reg_info *p = &cse_reg_info_table[regno]; - - /* If this entry has not been initialized, go ahead and initialize - it. */ - if (p->timestamp != cse_reg_info_timestamp) - get_cse_reg_info_1 (regno); - - return p; -} - -/* Clear the hash table and initialize each register with its own quantity, - for a new basic block. */ - -static void -new_basic_block (void) -{ - int i; - - next_qty = 0; - - /* Invalidate cse_reg_info_table. */ - cse_reg_info_timestamp++; - - /* Clear out hash table state for this pass. */ - CLEAR_HARD_REG_SET (hard_regs_in_table); - - /* The per-quantity values used to be initialized here, but it is - much faster to initialize each as it is made in `make_new_qty'. */ - - for (i = 0; i < HASH_SIZE; i++) - { - struct table_elt *first; - - first = table[i]; - if (first != NULL) - { - struct table_elt *last = first; - - table[i] = NULL; - - while (last->next_same_hash != NULL) - last = last->next_same_hash; - - /* Now relink this hash entire chain into - the free element list. */ - - last->next_same_hash = free_element_chain; - free_element_chain = first; - } - } - -#ifdef HAVE_cc0 - prev_insn_cc0 = 0; -#endif -} - -/* Say that register REG contains a quantity in mode MODE not in any - register before and initialize that quantity. */ - -static void -make_new_qty (unsigned int reg, enum machine_mode mode) -{ - int q; - struct qty_table_elem *ent; - struct reg_eqv_elem *eqv; - - gcc_assert (next_qty < max_qty); - - q = REG_QTY (reg) = next_qty++; - ent = &qty_table[q]; - ent->first_reg = reg; - ent->last_reg = reg; - ent->mode = mode; - ent->const_rtx = ent->const_insn = NULL_RTX; - ent->comparison_code = UNKNOWN; - - eqv = ®_eqv_table[reg]; - eqv->next = eqv->prev = -1; -} - -/* Make reg NEW equivalent to reg OLD. - OLD is not changing; NEW is. */ - -static void -make_regs_eqv (unsigned int new_reg, unsigned int old_reg) -{ - unsigned int lastr, firstr; - int q = REG_QTY (old_reg); - struct qty_table_elem *ent; - - ent = &qty_table[q]; - - /* Nothing should become eqv until it has a "non-invalid" qty number. */ - gcc_assert (REGNO_QTY_VALID_P (old_reg)); - - REG_QTY (new_reg) = q; - firstr = ent->first_reg; - lastr = ent->last_reg; - - /* Prefer fixed hard registers to anything. Prefer pseudo regs to other - hard regs. Among pseudos, if NEW will live longer than any other reg - of the same qty, and that is beyond the current basic block, - make it the new canonical replacement for this qty. */ - if (! (firstr < FIRST_PSEUDO_REGISTER && FIXED_REGNO_P (firstr)) - /* Certain fixed registers might be of the class NO_REGS. This means - that not only can they not be allocated by the compiler, but - they cannot be used in substitutions or canonicalizations - either. */ - && (new_reg >= FIRST_PSEUDO_REGISTER || REGNO_REG_CLASS (new_reg) != NO_REGS) - && ((new_reg < FIRST_PSEUDO_REGISTER && FIXED_REGNO_P (new_reg)) - || (new_reg >= FIRST_PSEUDO_REGISTER - && (firstr < FIRST_PSEUDO_REGISTER - || (bitmap_bit_p (cse_ebb_live_out, new_reg) - && !bitmap_bit_p (cse_ebb_live_out, firstr)) - || (bitmap_bit_p (cse_ebb_live_in, new_reg) - && !bitmap_bit_p (cse_ebb_live_in, firstr)))))) - { - reg_eqv_table[firstr].prev = new_reg; - reg_eqv_table[new_reg].next = firstr; - reg_eqv_table[new_reg].prev = -1; - ent->first_reg = new_reg; - } - else - { - /* If NEW is a hard reg (known to be non-fixed), insert at end. - Otherwise, insert before any non-fixed hard regs that are at the - end. Registers of class NO_REGS cannot be used as an - equivalent for anything. */ - while (lastr < FIRST_PSEUDO_REGISTER && reg_eqv_table[lastr].prev >= 0 - && (REGNO_REG_CLASS (lastr) == NO_REGS || ! FIXED_REGNO_P (lastr)) - && new_reg >= FIRST_PSEUDO_REGISTER) - lastr = reg_eqv_table[lastr].prev; - reg_eqv_table[new_reg].next = reg_eqv_table[lastr].next; - if (reg_eqv_table[lastr].next >= 0) - reg_eqv_table[reg_eqv_table[lastr].next].prev = new_reg; - else - qty_table[q].last_reg = new_reg; - reg_eqv_table[lastr].next = new_reg; - reg_eqv_table[new_reg].prev = lastr; - } -} - -/* Remove REG from its equivalence class. */ - -static void -delete_reg_equiv (unsigned int reg) -{ - struct qty_table_elem *ent; - int q = REG_QTY (reg); - int p, n; - - /* If invalid, do nothing. */ - if (! REGNO_QTY_VALID_P (reg)) - return; - - ent = &qty_table[q]; - - p = reg_eqv_table[reg].prev; - n = reg_eqv_table[reg].next; - - if (n != -1) - reg_eqv_table[n].prev = p; - else - ent->last_reg = p; - if (p != -1) - reg_eqv_table[p].next = n; - else - ent->first_reg = n; - - REG_QTY (reg) = -reg - 1; -} - -/* Remove any invalid expressions from the hash table - that refer to any of the registers contained in expression X. - - Make sure that newly inserted references to those registers - as subexpressions will be considered valid. - - mention_regs is not called when a register itself - is being stored in the table. - - Return 1 if we have done something that may have changed the hash code - of X. */ - -static int -mention_regs (rtx x) -{ - enum rtx_code code; - int i, j; - const char *fmt; - int changed = 0; - - if (x == 0) - return 0; - - code = GET_CODE (x); - if (code == REG) - { - unsigned int regno = REGNO (x); - unsigned int endregno = END_REGNO (x); - unsigned int i; - - for (i = regno; i < endregno; i++) - { - if (REG_IN_TABLE (i) >= 0 && REG_IN_TABLE (i) != REG_TICK (i)) - remove_invalid_refs (i); - - REG_IN_TABLE (i) = REG_TICK (i); - SUBREG_TICKED (i) = -1; - } - - return 0; - } - - /* If this is a SUBREG, we don't want to discard other SUBREGs of the same - pseudo if they don't use overlapping words. We handle only pseudos - here for simplicity. */ - if (code == SUBREG && REG_P (SUBREG_REG (x)) - && REGNO (SUBREG_REG (x)) >= FIRST_PSEUDO_REGISTER) - { - unsigned int i = REGNO (SUBREG_REG (x)); - - if (REG_IN_TABLE (i) >= 0 && REG_IN_TABLE (i) != REG_TICK (i)) - { - /* If REG_IN_TABLE (i) differs from REG_TICK (i) by one, and - the last store to this register really stored into this - subreg, then remove the memory of this subreg. - Otherwise, remove any memory of the entire register and - all its subregs from the table. */ - if (REG_TICK (i) - REG_IN_TABLE (i) > 1 - || SUBREG_TICKED (i) != REGNO (SUBREG_REG (x))) - remove_invalid_refs (i); - else - remove_invalid_subreg_refs (i, SUBREG_BYTE (x), GET_MODE (x)); - } - - REG_IN_TABLE (i) = REG_TICK (i); - SUBREG_TICKED (i) = REGNO (SUBREG_REG (x)); - return 0; - } - - /* If X is a comparison or a COMPARE and either operand is a register - that does not have a quantity, give it one. This is so that a later - call to record_jump_equiv won't cause X to be assigned a different - hash code and not found in the table after that call. - - It is not necessary to do this here, since rehash_using_reg can - fix up the table later, but doing this here eliminates the need to - call that expensive function in the most common case where the only - use of the register is in the comparison. */ - - if (code == COMPARE || COMPARISON_P (x)) - { - if (REG_P (XEXP (x, 0)) - && ! REGNO_QTY_VALID_P (REGNO (XEXP (x, 0)))) - if (insert_regs (XEXP (x, 0), NULL, 0)) - { - rehash_using_reg (XEXP (x, 0)); - changed = 1; - } - - if (REG_P (XEXP (x, 1)) - && ! REGNO_QTY_VALID_P (REGNO (XEXP (x, 1)))) - if (insert_regs (XEXP (x, 1), NULL, 0)) - { - rehash_using_reg (XEXP (x, 1)); - changed = 1; - } - } - - fmt = GET_RTX_FORMAT (code); - for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) - if (fmt[i] == 'e') - changed |= mention_regs (XEXP (x, i)); - else if (fmt[i] == 'E') - for (j = 0; j < XVECLEN (x, i); j++) - changed |= mention_regs (XVECEXP (x, i, j)); - - return changed; -} - -/* Update the register quantities for inserting X into the hash table - with a value equivalent to CLASSP. - (If the class does not contain a REG, it is irrelevant.) - If MODIFIED is nonzero, X is a destination; it is being modified. - Note that delete_reg_equiv should be called on a register - before insert_regs is done on that register with MODIFIED != 0. - - Nonzero value means that elements of reg_qty have changed - so X's hash code may be different. */ - -static int -insert_regs (rtx x, struct table_elt *classp, int modified) -{ - if (REG_P (x)) - { - unsigned int regno = REGNO (x); - int qty_valid; - - /* If REGNO is in the equivalence table already but is of the - wrong mode for that equivalence, don't do anything here. */ - - qty_valid = REGNO_QTY_VALID_P (regno); - if (qty_valid) - { - struct qty_table_elem *ent = &qty_table[REG_QTY (regno)]; - - if (ent->mode != GET_MODE (x)) - return 0; - } - - if (modified || ! qty_valid) - { - if (classp) - for (classp = classp->first_same_value; - classp != 0; - classp = classp->next_same_value) - if (REG_P (classp->exp) - && GET_MODE (classp->exp) == GET_MODE (x)) - { - unsigned c_regno = REGNO (classp->exp); - - gcc_assert (REGNO_QTY_VALID_P (c_regno)); - - /* Suppose that 5 is hard reg and 100 and 101 are - pseudos. Consider - - (set (reg:si 100) (reg:si 5)) - (set (reg:si 5) (reg:si 100)) - (set (reg:di 101) (reg:di 5)) - - We would now set REG_QTY (101) = REG_QTY (5), but the - entry for 5 is in SImode. When we use this later in - copy propagation, we get the register in wrong mode. */ - if (qty_table[REG_QTY (c_regno)].mode != GET_MODE (x)) - continue; - - make_regs_eqv (regno, c_regno); - return 1; - } - - /* Mention_regs for a SUBREG checks if REG_TICK is exactly one larger - than REG_IN_TABLE to find out if there was only a single preceding - invalidation - for the SUBREG - or another one, which would be - for the full register. However, if we find here that REG_TICK - indicates that the register is invalid, it means that it has - been invalidated in a separate operation. The SUBREG might be used - now (then this is a recursive call), or we might use the full REG - now and a SUBREG of it later. So bump up REG_TICK so that - mention_regs will do the right thing. */ - if (! modified - && REG_IN_TABLE (regno) >= 0 - && REG_TICK (regno) == REG_IN_TABLE (regno) + 1) - REG_TICK (regno)++; - make_new_qty (regno, GET_MODE (x)); - return 1; - } - - return 0; - } - - /* If X is a SUBREG, we will likely be inserting the inner register in the - table. If that register doesn't have an assigned quantity number at - this point but does later, the insertion that we will be doing now will - not be accessible because its hash code will have changed. So assign - a quantity number now. */ - - else if (GET_CODE (x) == SUBREG && REG_P (SUBREG_REG (x)) - && ! REGNO_QTY_VALID_P (REGNO (SUBREG_REG (x)))) - { - insert_regs (SUBREG_REG (x), NULL, 0); - mention_regs (x); - return 1; - } - else - return mention_regs (x); -} - - -/* Compute upper and lower anchors for CST. Also compute the offset of CST - from these anchors/bases such that *_BASE + *_OFFS = CST. Return false iff - CST is equal to an anchor. */ - -static bool -compute_const_anchors (rtx cst, - HOST_WIDE_INT *lower_base, HOST_WIDE_INT *lower_offs, - HOST_WIDE_INT *upper_base, HOST_WIDE_INT *upper_offs) -{ - HOST_WIDE_INT n = INTVAL (cst); - - *lower_base = n & ~(targetm.const_anchor - 1); - if (*lower_base == n) - return false; - - *upper_base = - (n + (targetm.const_anchor - 1)) & ~(targetm.const_anchor - 1); - *upper_offs = n - *upper_base; - *lower_offs = n - *lower_base; - return true; -} - -/* Insert the equivalence between ANCHOR and (REG + OFF) in mode MODE. */ - -static void -insert_const_anchor (HOST_WIDE_INT anchor, rtx reg, HOST_WIDE_INT offs, - enum machine_mode mode) -{ - struct table_elt *elt; - unsigned hash; - rtx anchor_exp; - rtx exp; - - anchor_exp = GEN_INT (anchor); - hash = HASH (anchor_exp, mode); - elt = lookup (anchor_exp, hash, mode); - if (!elt) - elt = insert (anchor_exp, NULL, hash, mode); - - exp = plus_constant (mode, reg, offs); - /* REG has just been inserted and the hash codes recomputed. */ - mention_regs (exp); - hash = HASH (exp, mode); - - /* Use the cost of the register rather than the whole expression. When - looking up constant anchors we will further offset the corresponding - expression therefore it does not make sense to prefer REGs over - reg-immediate additions. Prefer instead the oldest expression. Also - don't prefer pseudos over hard regs so that we derive constants in - argument registers from other argument registers rather than from the - original pseudo that was used to synthesize the constant. */ - insert_with_costs (exp, elt, hash, mode, COST (reg), 1); -} - -/* The constant CST is equivalent to the register REG. Create - equivalences between the two anchors of CST and the corresponding - register-offset expressions using REG. */ - -static void -insert_const_anchors (rtx reg, rtx cst, enum machine_mode mode) -{ - HOST_WIDE_INT lower_base, lower_offs, upper_base, upper_offs; - - if (!compute_const_anchors (cst, &lower_base, &lower_offs, - &upper_base, &upper_offs)) - return; - - /* Ignore anchors of value 0. Constants accessible from zero are - simple. */ - if (lower_base != 0) - insert_const_anchor (lower_base, reg, -lower_offs, mode); - - if (upper_base != 0) - insert_const_anchor (upper_base, reg, -upper_offs, mode); -} - -/* We need to express ANCHOR_ELT->exp + OFFS. Walk the equivalence list of - ANCHOR_ELT and see if offsetting any of the entries by OFFS would create a - valid expression. Return the cheapest and oldest of such expressions. In - *OLD, return how old the resulting expression is compared to the other - equivalent expressions. */ - -static rtx -find_reg_offset_for_const (struct table_elt *anchor_elt, HOST_WIDE_INT offs, - unsigned *old) -{ - struct table_elt *elt; - unsigned idx; - struct table_elt *match_elt; - rtx match; - - /* Find the cheapest and *oldest* expression to maximize the chance of - reusing the same pseudo. */ - - match_elt = NULL; - match = NULL_RTX; - for (elt = anchor_elt->first_same_value, idx = 0; - elt; - elt = elt->next_same_value, idx++) - { - if (match_elt && CHEAPER (match_elt, elt)) - return match; - - if (REG_P (elt->exp) - || (GET_CODE (elt->exp) == PLUS - && REG_P (XEXP (elt->exp, 0)) - && GET_CODE (XEXP (elt->exp, 1)) == CONST_INT)) - { - rtx x; - - /* Ignore expressions that are no longer valid. */ - if (!REG_P (elt->exp) && !exp_equiv_p (elt->exp, elt->exp, 1, false)) - continue; - - x = plus_constant (GET_MODE (elt->exp), elt->exp, offs); - if (REG_P (x) - || (GET_CODE (x) == PLUS - && IN_RANGE (INTVAL (XEXP (x, 1)), - -targetm.const_anchor, - targetm.const_anchor - 1))) - { - match = x; - match_elt = elt; - *old = idx; - } - } - } - - return match; -} - -/* Try to express the constant SRC_CONST using a register+offset expression - derived from a constant anchor. Return it if successful or NULL_RTX, - otherwise. */ - -static rtx -try_const_anchors (rtx src_const, enum machine_mode mode) -{ - struct table_elt *lower_elt, *upper_elt; - HOST_WIDE_INT lower_base, lower_offs, upper_base, upper_offs; - rtx lower_anchor_rtx, upper_anchor_rtx; - rtx lower_exp = NULL_RTX, upper_exp = NULL_RTX; - unsigned lower_old, upper_old; - - if (!compute_const_anchors (src_const, &lower_base, &lower_offs, - &upper_base, &upper_offs)) - return NULL_RTX; - - lower_anchor_rtx = GEN_INT (lower_base); - upper_anchor_rtx = GEN_INT (upper_base); - lower_elt = lookup (lower_anchor_rtx, HASH (lower_anchor_rtx, mode), mode); - upper_elt = lookup (upper_anchor_rtx, HASH (upper_anchor_rtx, mode), mode); - - if (lower_elt) - lower_exp = find_reg_offset_for_const (lower_elt, lower_offs, &lower_old); - if (upper_elt) - upper_exp = find_reg_offset_for_const (upper_elt, upper_offs, &upper_old); - - if (!lower_exp) - return upper_exp; - if (!upper_exp) - return lower_exp; - - /* Return the older expression. */ - return (upper_old > lower_old ? upper_exp : lower_exp); -} - -/* Look in or update the hash table. */ - -/* Remove table element ELT from use in the table. - HASH is its hash code, made using the HASH macro. - It's an argument because often that is known in advance - and we save much time not recomputing it. */ - -static void -remove_from_table (struct table_elt *elt, unsigned int hash) -{ - if (elt == 0) - return; - - /* Mark this element as removed. See cse_insn. */ - elt->first_same_value = 0; - - /* Remove the table element from its equivalence class. */ - - { - struct table_elt *prev = elt->prev_same_value; - struct table_elt *next = elt->next_same_value; - - if (next) - next->prev_same_value = prev; - - if (prev) - prev->next_same_value = next; - else - { - struct table_elt *newfirst = next; - while (next) - { - next->first_same_value = newfirst; - next = next->next_same_value; - } - } - } - - /* Remove the table element from its hash bucket. */ - - { - struct table_elt *prev = elt->prev_same_hash; - struct table_elt *next = elt->next_same_hash; - - if (next) - next->prev_same_hash = prev; - - if (prev) - prev->next_same_hash = next; - else if (table[hash] == elt) - table[hash] = next; - else - { - /* This entry is not in the proper hash bucket. This can happen - when two classes were merged by `merge_equiv_classes'. Search - for the hash bucket that it heads. This happens only very - rarely, so the cost is acceptable. */ - for (hash = 0; hash < HASH_SIZE; hash++) - if (table[hash] == elt) - table[hash] = next; - } - } - - /* Remove the table element from its related-value circular chain. */ - - if (elt->related_value != 0 && elt->related_value != elt) - { - struct table_elt *p = elt->related_value; - - while (p->related_value != elt) - p = p->related_value; - p->related_value = elt->related_value; - if (p->related_value == p) - p->related_value = 0; - } - - /* Now add it to the free element chain. */ - elt->next_same_hash = free_element_chain; - free_element_chain = elt; -} - -/* Same as above, but X is a pseudo-register. */ - -static void -remove_pseudo_from_table (rtx x, unsigned int hash) -{ - struct table_elt *elt; - - /* Because a pseudo-register can be referenced in more than one - mode, we might have to remove more than one table entry. */ - while ((elt = lookup_for_remove (x, hash, VOIDmode))) - remove_from_table (elt, hash); -} - -/* Look up X in the hash table and return its table element, - or 0 if X is not in the table. - - MODE is the machine-mode of X, or if X is an integer constant - with VOIDmode then MODE is the mode with which X will be used. - - Here we are satisfied to find an expression whose tree structure - looks like X. */ - -static struct table_elt * -lookup (rtx x, unsigned int hash, enum machine_mode mode) -{ - struct table_elt *p; - - for (p = table[hash]; p; p = p->next_same_hash) - if (mode == p->mode && ((x == p->exp && REG_P (x)) - || exp_equiv_p (x, p->exp, !REG_P (x), false))) - return p; - - return 0; -} - -/* Like `lookup' but don't care whether the table element uses invalid regs. - Also ignore discrepancies in the machine mode of a register. */ - -static struct table_elt * -lookup_for_remove (rtx x, unsigned int hash, enum machine_mode mode) -{ - struct table_elt *p; - - if (REG_P (x)) - { - unsigned int regno = REGNO (x); - - /* Don't check the machine mode when comparing registers; - invalidating (REG:SI 0) also invalidates (REG:DF 0). */ - for (p = table[hash]; p; p = p->next_same_hash) - if (REG_P (p->exp) - && REGNO (p->exp) == regno) - return p; - } - else - { - for (p = table[hash]; p; p = p->next_same_hash) - if (mode == p->mode - && (x == p->exp || exp_equiv_p (x, p->exp, 0, false))) - return p; - } - - return 0; -} - -/* Look for an expression equivalent to X and with code CODE. - If one is found, return that expression. */ - -static rtx -lookup_as_function (rtx x, enum rtx_code code) -{ - struct table_elt *p - = lookup (x, SAFE_HASH (x, VOIDmode), GET_MODE (x)); - - if (p == 0) - return 0; - - for (p = p->first_same_value; p; p = p->next_same_value) - if (GET_CODE (p->exp) == code - /* Make sure this is a valid entry in the table. */ - && exp_equiv_p (p->exp, p->exp, 1, false)) - return p->exp; - - return 0; -} - -/* Insert X in the hash table, assuming HASH is its hash code and - CLASSP is an element of the class it should go in (or 0 if a new - class should be made). COST is the code of X and reg_cost is the - cost of registers in X. It is inserted at the proper position to - keep the class in the order cheapest first. - - MODE is the machine-mode of X, or if X is an integer constant - with VOIDmode then MODE is the mode with which X will be used. - - For elements of equal cheapness, the most recent one - goes in front, except that the first element in the list - remains first unless a cheaper element is added. The order of - pseudo-registers does not matter, as canon_reg will be called to - find the cheapest when a register is retrieved from the table. - - The in_memory field in the hash table element is set to 0. - The caller must set it nonzero if appropriate. - - You should call insert_regs (X, CLASSP, MODIFY) before calling here, - and if insert_regs returns a nonzero value - you must then recompute its hash code before calling here. - - If necessary, update table showing constant values of quantities. */ - -static struct table_elt * -insert_with_costs (rtx x, struct table_elt *classp, unsigned int hash, - enum machine_mode mode, int cost, int reg_cost) -{ - struct table_elt *elt; - - /* If X is a register and we haven't made a quantity for it, - something is wrong. */ - gcc_assert (!REG_P (x) || REGNO_QTY_VALID_P (REGNO (x))); - - /* If X is a hard register, show it is being put in the table. */ - if (REG_P (x) && REGNO (x) < FIRST_PSEUDO_REGISTER) - add_to_hard_reg_set (&hard_regs_in_table, GET_MODE (x), REGNO (x)); - - /* Put an element for X into the right hash bucket. */ - - elt = free_element_chain; - if (elt) - free_element_chain = elt->next_same_hash; - else - elt = XNEW (struct table_elt); - - elt->exp = x; - elt->canon_exp = NULL_RTX; - elt->cost = cost; - elt->regcost = reg_cost; - elt->next_same_value = 0; - elt->prev_same_value = 0; - elt->next_same_hash = table[hash]; - elt->prev_same_hash = 0; - elt->related_value = 0; - elt->in_memory = 0; - elt->mode = mode; - elt->is_const = (CONSTANT_P (x) || fixed_base_plus_p (x)); - - if (table[hash]) - table[hash]->prev_same_hash = elt; - table[hash] = elt; - - /* Put it into the proper value-class. */ - if (classp) - { - classp = classp->first_same_value; - if (CHEAPER (elt, classp)) - /* Insert at the head of the class. */ - { - struct table_elt *p; - elt->next_same_value = classp; - classp->prev_same_value = elt; - elt->first_same_value = elt; - - for (p = classp; p; p = p->next_same_value) - p->first_same_value = elt; - } - else - { - /* Insert not at head of the class. */ - /* Put it after the last element cheaper than X. */ - struct table_elt *p, *next; - - for (p = classp; - (next = p->next_same_value) && CHEAPER (next, elt); - p = next) - ; - - /* Put it after P and before NEXT. */ - elt->next_same_value = next; - if (next) - next->prev_same_value = elt; - - elt->prev_same_value = p; - p->next_same_value = elt; - elt->first_same_value = classp; - } - } - else - elt->first_same_value = elt; - - /* If this is a constant being set equivalent to a register or a register - being set equivalent to a constant, note the constant equivalence. - - If this is a constant, it cannot be equivalent to a different constant, - and a constant is the only thing that can be cheaper than a register. So - we know the register is the head of the class (before the constant was - inserted). - - If this is a register that is not already known equivalent to a - constant, we must check the entire class. - - If this is a register that is already known equivalent to an insn, - update the qtys `const_insn' to show that `this_insn' is the latest - insn making that quantity equivalent to the constant. */ - - if (elt->is_const && classp && REG_P (classp->exp) - && !REG_P (x)) - { - int exp_q = REG_QTY (REGNO (classp->exp)); - struct qty_table_elem *exp_ent = &qty_table[exp_q]; - - exp_ent->const_rtx = gen_lowpart (exp_ent->mode, x); - exp_ent->const_insn = this_insn; - } - - else if (REG_P (x) - && classp - && ! qty_table[REG_QTY (REGNO (x))].const_rtx - && ! elt->is_const) - { - struct table_elt *p; - - for (p = classp; p != 0; p = p->next_same_value) - { - if (p->is_const && !REG_P (p->exp)) - { - int x_q = REG_QTY (REGNO (x)); - struct qty_table_elem *x_ent = &qty_table[x_q]; - - x_ent->const_rtx - = gen_lowpart (GET_MODE (x), p->exp); - x_ent->const_insn = this_insn; - break; - } - } - } - - else if (REG_P (x) - && qty_table[REG_QTY (REGNO (x))].const_rtx - && GET_MODE (x) == qty_table[REG_QTY (REGNO (x))].mode) - qty_table[REG_QTY (REGNO (x))].const_insn = this_insn; - - /* If this is a constant with symbolic value, - and it has a term with an explicit integer value, - link it up with related expressions. */ - if (GET_CODE (x) == CONST) - { - rtx subexp = get_related_value (x); - unsigned subhash; - struct table_elt *subelt, *subelt_prev; - - if (subexp != 0) - { - /* Get the integer-free subexpression in the hash table. */ - subhash = SAFE_HASH (subexp, mode); - subelt = lookup (subexp, subhash, mode); - if (subelt == 0) - subelt = insert (subexp, NULL, subhash, mode); - /* Initialize SUBELT's circular chain if it has none. */ - if (subelt->related_value == 0) - subelt->related_value = subelt; - /* Find the element in the circular chain that precedes SUBELT. */ - subelt_prev = subelt; - while (subelt_prev->related_value != subelt) - subelt_prev = subelt_prev->related_value; - /* Put new ELT into SUBELT's circular chain just before SUBELT. - This way the element that follows SUBELT is the oldest one. */ - elt->related_value = subelt_prev->related_value; - subelt_prev->related_value = elt; - } - } - - return elt; -} - -/* Wrap insert_with_costs by passing the default costs. */ - -static struct table_elt * -insert (rtx x, struct table_elt *classp, unsigned int hash, - enum machine_mode mode) -{ - return - insert_with_costs (x, classp, hash, mode, COST (x), approx_reg_cost (x)); -} - - -/* Given two equivalence classes, CLASS1 and CLASS2, put all the entries from - CLASS2 into CLASS1. This is done when we have reached an insn which makes - the two classes equivalent. - - CLASS1 will be the surviving class; CLASS2 should not be used after this - call. - - Any invalid entries in CLASS2 will not be copied. */ - -static void -merge_equiv_classes (struct table_elt *class1, struct table_elt *class2) -{ - struct table_elt *elt, *next, *new_elt; - - /* Ensure we start with the head of the classes. */ - class1 = class1->first_same_value; - class2 = class2->first_same_value; - - /* If they were already equal, forget it. */ - if (class1 == class2) - return; - - for (elt = class2; elt; elt = next) - { - unsigned int hash; - rtx exp = elt->exp; - enum machine_mode mode = elt->mode; - - next = elt->next_same_value; - - /* Remove old entry, make a new one in CLASS1's class. - Don't do this for invalid entries as we cannot find their - hash code (it also isn't necessary). */ - if (REG_P (exp) || exp_equiv_p (exp, exp, 1, false)) - { - bool need_rehash = false; - - hash_arg_in_memory = 0; - hash = HASH (exp, mode); - - if (REG_P (exp)) - { - need_rehash = REGNO_QTY_VALID_P (REGNO (exp)); - delete_reg_equiv (REGNO (exp)); - } - - if (REG_P (exp) && REGNO (exp) >= FIRST_PSEUDO_REGISTER) - remove_pseudo_from_table (exp, hash); - else - remove_from_table (elt, hash); - - if (insert_regs (exp, class1, 0) || need_rehash) - { - rehash_using_reg (exp); - hash = HASH (exp, mode); - } - new_elt = insert (exp, class1, hash, mode); - new_elt->in_memory = hash_arg_in_memory; - } - } -} - -/* Flush the entire hash table. */ - -static void -flush_hash_table (void) -{ - int i; - struct table_elt *p; - - for (i = 0; i < HASH_SIZE; i++) - for (p = table[i]; p; p = table[i]) - { - /* Note that invalidate can remove elements - after P in the current hash chain. */ - if (REG_P (p->exp)) - invalidate (p->exp, VOIDmode); - else - remove_from_table (p, i); - } -} - -/* Function called for each rtx to check whether true dependence exist. */ -struct check_dependence_data -{ - enum machine_mode mode; - rtx exp; - rtx addr; -}; - -static int -check_dependence (rtx *x, void *data) -{ - struct check_dependence_data *d = (struct check_dependence_data *) data; - if (*x && MEM_P (*x)) - return canon_true_dependence (d->exp, d->mode, d->addr, *x, NULL_RTX); - else - return 0; -} - -/* Remove from the hash table, or mark as invalid, all expressions whose - values could be altered by storing in X. X is a register, a subreg, or - a memory reference with nonvarying address (because, when a memory - reference with a varying address is stored in, all memory references are - removed by invalidate_memory so specific invalidation is superfluous). - FULL_MODE, if not VOIDmode, indicates that this much should be - invalidated instead of just the amount indicated by the mode of X. This - is only used for bitfield stores into memory. - - A nonvarying address may be just a register or just a symbol reference, - or it may be either of those plus a numeric offset. */ - -static void -invalidate (rtx x, enum machine_mode full_mode) -{ - int i; - struct table_elt *p; - rtx addr; - - switch (GET_CODE (x)) - { - case REG: - { - /* If X is a register, dependencies on its contents are recorded - through the qty number mechanism. Just change the qty number of - the register, mark it as invalid for expressions that refer to it, - and remove it itself. */ - unsigned int regno = REGNO (x); - unsigned int hash = HASH (x, GET_MODE (x)); - - /* Remove REGNO from any quantity list it might be on and indicate - that its value might have changed. If it is a pseudo, remove its - entry from the hash table. - - For a hard register, we do the first two actions above for any - additional hard registers corresponding to X. Then, if any of these - registers are in the table, we must remove any REG entries that - overlap these registers. */ - - delete_reg_equiv (regno); - REG_TICK (regno)++; - SUBREG_TICKED (regno) = -1; - - if (regno >= FIRST_PSEUDO_REGISTER) - remove_pseudo_from_table (x, hash); - else - { - HOST_WIDE_INT in_table - = TEST_HARD_REG_BIT (hard_regs_in_table, regno); - unsigned int endregno = END_HARD_REGNO (x); - unsigned int tregno, tendregno, rn; - struct table_elt *p, *next; - - CLEAR_HARD_REG_BIT (hard_regs_in_table, regno); - - for (rn = regno + 1; rn < endregno; rn++) - { - in_table |= TEST_HARD_REG_BIT (hard_regs_in_table, rn); - CLEAR_HARD_REG_BIT (hard_regs_in_table, rn); - delete_reg_equiv (rn); - REG_TICK (rn)++; - SUBREG_TICKED (rn) = -1; - } - - if (in_table) - for (hash = 0; hash < HASH_SIZE; hash++) - for (p = table[hash]; p; p = next) - { - next = p->next_same_hash; - - if (!REG_P (p->exp) - || REGNO (p->exp) >= FIRST_PSEUDO_REGISTER) - continue; - - tregno = REGNO (p->exp); - tendregno = END_HARD_REGNO (p->exp); - if (tendregno > regno && tregno < endregno) - remove_from_table (p, hash); - } - } - } - return; - - case SUBREG: - invalidate (SUBREG_REG (x), VOIDmode); - return; - - case PARALLEL: - for (i = XVECLEN (x, 0) - 1; i >= 0; --i) - invalidate (XVECEXP (x, 0, i), VOIDmode); - return; - - case EXPR_LIST: - /* This is part of a disjoint return value; extract the location in - question ignoring the offset. */ - invalidate (XEXP (x, 0), VOIDmode); - return; - - case MEM: - addr = canon_rtx (get_addr (XEXP (x, 0))); - /* Calculate the canonical version of X here so that - true_dependence doesn't generate new RTL for X on each call. */ - x = canon_rtx (x); - - /* Remove all hash table elements that refer to overlapping pieces of - memory. */ - if (full_mode == VOIDmode) - full_mode = GET_MODE (x); - - for (i = 0; i < HASH_SIZE; i++) - { - struct table_elt *next; - - for (p = table[i]; p; p = next) - { - next = p->next_same_hash; - if (p->in_memory) - { - struct check_dependence_data d; - - /* Just canonicalize the expression once; - otherwise each time we call invalidate - true_dependence will canonicalize the - expression again. */ - if (!p->canon_exp) - p->canon_exp = canon_rtx (p->exp); - d.exp = x; - d.addr = addr; - d.mode = full_mode; - if (for_each_rtx (&p->canon_exp, check_dependence, &d)) - remove_from_table (p, i); - } - } - } - return; - - default: - gcc_unreachable (); - } -} - -/* Remove all expressions that refer to register REGNO, - since they are already invalid, and we are about to - mark that register valid again and don't want the old - expressions to reappear as valid. */ - -static void -remove_invalid_refs (unsigned int regno) -{ - unsigned int i; - struct table_elt *p, *next; - - for (i = 0; i < HASH_SIZE; i++) - for (p = table[i]; p; p = next) - { - next = p->next_same_hash; - if (!REG_P (p->exp) - && refers_to_regno_p (regno, regno + 1, p->exp, (rtx *) 0)) - remove_from_table (p, i); - } -} - -/* Likewise for a subreg with subreg_reg REGNO, subreg_byte OFFSET, - and mode MODE. */ -static void -remove_invalid_subreg_refs (unsigned int regno, unsigned int offset, - enum machine_mode mode) -{ - unsigned int i; - struct table_elt *p, *next; - unsigned int end = offset + (GET_MODE_SIZE (mode) - 1); - - for (i = 0; i < HASH_SIZE; i++) - for (p = table[i]; p; p = next) - { - rtx exp = p->exp; - next = p->next_same_hash; - - if (!REG_P (exp) - && (GET_CODE (exp) != SUBREG - || !REG_P (SUBREG_REG (exp)) - || REGNO (SUBREG_REG (exp)) != regno - || (((SUBREG_BYTE (exp) - + (GET_MODE_SIZE (GET_MODE (exp)) - 1)) >= offset) - && SUBREG_BYTE (exp) <= end)) - && refers_to_regno_p (regno, regno + 1, p->exp, (rtx *) 0)) - remove_from_table (p, i); - } -} - -/* Recompute the hash codes of any valid entries in the hash table that - reference X, if X is a register, or SUBREG_REG (X) if X is a SUBREG. - - This is called when we make a jump equivalence. */ - -static void -rehash_using_reg (rtx x) -{ - unsigned int i; - struct table_elt *p, *next; - unsigned hash; - - if (GET_CODE (x) == SUBREG) - x = SUBREG_REG (x); - - /* If X is not a register or if the register is known not to be in any - valid entries in the table, we have no work to do. */ - - if (!REG_P (x) - || REG_IN_TABLE (REGNO (x)) < 0 - || REG_IN_TABLE (REGNO (x)) != REG_TICK (REGNO (x))) - return; - - /* Scan all hash chains looking for valid entries that mention X. - If we find one and it is in the wrong hash chain, move it. */ - - for (i = 0; i < HASH_SIZE; i++) - for (p = table[i]; p; p = next) - { - next = p->next_same_hash; - if (reg_mentioned_p (x, p->exp) - && exp_equiv_p (p->exp, p->exp, 1, false) - && i != (hash = SAFE_HASH (p->exp, p->mode))) - { - if (p->next_same_hash) - p->next_same_hash->prev_same_hash = p->prev_same_hash; - - if (p->prev_same_hash) - p->prev_same_hash->next_same_hash = p->next_same_hash; - else - table[i] = p->next_same_hash; - - p->next_same_hash = table[hash]; - p->prev_same_hash = 0; - if (table[hash]) - table[hash]->prev_same_hash = p; - table[hash] = p; - } - } -} - -/* Remove from the hash table any expression that is a call-clobbered - register. Also update their TICK values. */ - -static void -invalidate_for_call (void) -{ - unsigned int regno, endregno; - unsigned int i; - unsigned hash; - struct table_elt *p, *next; - int in_table = 0; - hard_reg_set_iterator hrsi; - - /* Go through all the hard registers. For each that is clobbered in - a CALL_INSN, remove the register from quantity chains and update - reg_tick if defined. Also see if any of these registers is currently - in the table. */ - EXECUTE_IF_SET_IN_HARD_REG_SET (regs_invalidated_by_call, 0, regno, hrsi) - { - delete_reg_equiv (regno); - if (REG_TICK (regno) >= 0) - { - REG_TICK (regno)++; - SUBREG_TICKED (regno) = -1; - } - in_table |= (TEST_HARD_REG_BIT (hard_regs_in_table, regno) != 0); - } - - /* In the case where we have no call-clobbered hard registers in the - table, we are done. Otherwise, scan the table and remove any - entry that overlaps a call-clobbered register. */ - - if (in_table) - for (hash = 0; hash < HASH_SIZE; hash++) - for (p = table[hash]; p; p = next) - { - next = p->next_same_hash; - - if (!REG_P (p->exp) - || REGNO (p->exp) >= FIRST_PSEUDO_REGISTER) - continue; - - regno = REGNO (p->exp); - endregno = END_HARD_REGNO (p->exp); - - for (i = regno; i < endregno; i++) - if (TEST_HARD_REG_BIT (regs_invalidated_by_call, i)) - { - remove_from_table (p, hash); - break; - } - } -} - -/* Given an expression X of type CONST, - and ELT which is its table entry (or 0 if it - is not in the hash table), - return an alternate expression for X as a register plus integer. - If none can be found, return 0. */ - -static rtx -use_related_value (rtx x, struct table_elt *elt) -{ - struct table_elt *relt = 0; - struct table_elt *p, *q; - HOST_WIDE_INT offset; - - /* First, is there anything related known? - If we have a table element, we can tell from that. - Otherwise, must look it up. */ - - if (elt != 0 && elt->related_value != 0) - relt = elt; - else if (elt == 0 && GET_CODE (x) == CONST) - { - rtx subexp = get_related_value (x); - if (subexp != 0) - relt = lookup (subexp, - SAFE_HASH (subexp, GET_MODE (subexp)), - GET_MODE (subexp)); - } - - if (relt == 0) - return 0; - - /* Search all related table entries for one that has an - equivalent register. */ - - p = relt; - while (1) - { - /* This loop is strange in that it is executed in two different cases. - The first is when X is already in the table. Then it is searching - the RELATED_VALUE list of X's class (RELT). The second case is when - X is not in the table. Then RELT points to a class for the related - value. - - Ensure that, whatever case we are in, that we ignore classes that have - the same value as X. */ - - if (rtx_equal_p (x, p->exp)) - q = 0; - else - for (q = p->first_same_value; q; q = q->next_same_value) - if (REG_P (q->exp)) - break; - - if (q) - break; - - p = p->related_value; - - /* We went all the way around, so there is nothing to be found. - Alternatively, perhaps RELT was in the table for some other reason - and it has no related values recorded. */ - if (p == relt || p == 0) - break; - } - - if (q == 0) - return 0; - - offset = (get_integer_term (x) - get_integer_term (p->exp)); - /* Note: OFFSET may be 0 if P->xexp and X are related by commutativity. */ - return plus_constant (q->mode, q->exp, offset); -} - - -/* Hash a string. Just add its bytes up. */ -static inline unsigned -hash_rtx_string (const char *ps) -{ - unsigned hash = 0; - const unsigned char *p = (const unsigned char *) ps; - - if (p) - while (*p) - hash += *p++; - - return hash; -} - -/* Same as hash_rtx, but call CB on each rtx if it is not NULL. - When the callback returns true, we continue with the new rtx. */ - -unsigned -hash_rtx_cb (const_rtx x, enum machine_mode mode, - int *do_not_record_p, int *hash_arg_in_memory_p, - bool have_reg_qty, hash_rtx_callback_function cb) -{ - int i, j; - unsigned hash = 0; - enum rtx_code code; - const char *fmt; - enum machine_mode newmode; - rtx newx; - - /* Used to turn recursion into iteration. We can't rely on GCC's - tail-recursion elimination since we need to keep accumulating values - in HASH. */ - repeat: - if (x == 0) - return hash; - - /* Invoke the callback first. */ - if (cb != NULL - && ((*cb) (x, mode, &newx, &newmode))) - { - hash += hash_rtx_cb (newx, newmode, do_not_record_p, - hash_arg_in_memory_p, have_reg_qty, cb); - return hash; - } - - code = GET_CODE (x); - switch (code) - { - case REG: - { - unsigned int regno = REGNO (x); - - if (do_not_record_p && !reload_completed) - { - /* On some machines, we can't record any non-fixed hard register, - because extending its life will cause reload problems. We - consider ap, fp, sp, gp to be fixed for this purpose. - - We also consider CCmode registers to be fixed for this purpose; - failure to do so leads to failure to simplify 0<100 type of - conditionals. - - On all machines, we can't record any global registers. - Nor should we record any register that is in a small - class, as defined by TARGET_CLASS_LIKELY_SPILLED_P. */ - bool record; - - if (regno >= FIRST_PSEUDO_REGISTER) - record = true; - else if (x == frame_pointer_rtx - || x == hard_frame_pointer_rtx - || x == arg_pointer_rtx - || x == stack_pointer_rtx - || x == pic_offset_table_rtx) - record = true; - else if (global_regs[regno]) - record = false; - else if (fixed_regs[regno]) - record = true; - else if (GET_MODE_CLASS (GET_MODE (x)) == MODE_CC) - record = true; - else if (targetm.small_register_classes_for_mode_p (GET_MODE (x))) - record = false; - else if (targetm.class_likely_spilled_p (REGNO_REG_CLASS (regno))) - record = false; - else - record = true; - - if (!record) - { - *do_not_record_p = 1; - return 0; - } - } - - hash += ((unsigned int) REG << 7); - hash += (have_reg_qty ? (unsigned) REG_QTY (regno) : regno); - return hash; - } - - /* We handle SUBREG of a REG specially because the underlying - reg changes its hash value with every value change; we don't - want to have to forget unrelated subregs when one subreg changes. */ - case SUBREG: - { - if (REG_P (SUBREG_REG (x))) - { - hash += (((unsigned int) SUBREG << 7) - + REGNO (SUBREG_REG (x)) - + (SUBREG_BYTE (x) / UNITS_PER_WORD)); - return hash; - } - break; - } - - case CONST_INT: - hash += (((unsigned int) CONST_INT << 7) + (unsigned int) mode - + (unsigned int) INTVAL (x)); - return hash; - - case CONST_DOUBLE: - /* This is like the general case, except that it only counts - the integers representing the constant. */ - hash += (unsigned int) code + (unsigned int) GET_MODE (x); - if (GET_MODE (x) != VOIDmode) - hash += real_hash (CONST_DOUBLE_REAL_VALUE (x)); - else - hash += ((unsigned int) CONST_DOUBLE_LOW (x) - + (unsigned int) CONST_DOUBLE_HIGH (x)); - return hash; - - case CONST_FIXED: - hash += (unsigned int) code + (unsigned int) GET_MODE (x); - hash += fixed_hash (CONST_FIXED_VALUE (x)); - return hash; - - case CONST_VECTOR: - { - int units; - rtx elt; - - units = CONST_VECTOR_NUNITS (x); - - for (i = 0; i < units; ++i) - { - elt = CONST_VECTOR_ELT (x, i); - hash += hash_rtx_cb (elt, GET_MODE (elt), - do_not_record_p, hash_arg_in_memory_p, - have_reg_qty, cb); - } - - return hash; - } - - /* Assume there is only one rtx object for any given label. */ - case LABEL_REF: - /* We don't hash on the address of the CODE_LABEL to avoid bootstrap - differences and differences between each stage's debugging dumps. */ - hash += (((unsigned int) LABEL_REF << 7) - + CODE_LABEL_NUMBER (XEXP (x, 0))); - return hash; - - case SYMBOL_REF: - { - /* Don't hash on the symbol's address to avoid bootstrap differences. - Different hash values may cause expressions to be recorded in - different orders and thus different registers to be used in the - final assembler. This also avoids differences in the dump files - between various stages. */ - unsigned int h = 0; - const unsigned char *p = (const unsigned char *) XSTR (x, 0); - - while (*p) - h += (h << 7) + *p++; /* ??? revisit */ - - hash += ((unsigned int) SYMBOL_REF << 7) + h; - return hash; - } - - case MEM: - /* We don't record if marked volatile or if BLKmode since we don't - know the size of the move. */ - if (do_not_record_p && (MEM_VOLATILE_P (x) || GET_MODE (x) == BLKmode)) - { - *do_not_record_p = 1; - return 0; - } - if (hash_arg_in_memory_p && !MEM_READONLY_P (x)) - *hash_arg_in_memory_p = 1; - - /* Now that we have already found this special case, - might as well speed it up as much as possible. */ - hash += (unsigned) MEM; - x = XEXP (x, 0); - goto repeat; - - case USE: - /* A USE that mentions non-volatile memory needs special - handling since the MEM may be BLKmode which normally - prevents an entry from being made. Pure calls are - marked by a USE which mentions BLKmode memory. - See calls.c:emit_call_1. */ - if (MEM_P (XEXP (x, 0)) - && ! MEM_VOLATILE_P (XEXP (x, 0))) - { - hash += (unsigned) USE; - x = XEXP (x, 0); - - if (hash_arg_in_memory_p && !MEM_READONLY_P (x)) - *hash_arg_in_memory_p = 1; - - /* Now that we have already found this special case, - might as well speed it up as much as possible. */ - hash += (unsigned) MEM; - x = XEXP (x, 0); - goto repeat; - } - break; - - case PRE_DEC: - case PRE_INC: - case POST_DEC: - case POST_INC: - case PRE_MODIFY: - case POST_MODIFY: - case PC: - case CC0: - case CALL: - case UNSPEC_VOLATILE: - if (do_not_record_p) { - *do_not_record_p = 1; - return 0; - } - else - return hash; - break; - - case ASM_OPERANDS: - if (do_not_record_p && MEM_VOLATILE_P (x)) - { - *do_not_record_p = 1; - return 0; - } - else - { - /* We don't want to take the filename and line into account. */ - hash += (unsigned) code + (unsigned) GET_MODE (x) - + hash_rtx_string (ASM_OPERANDS_TEMPLATE (x)) - + hash_rtx_string (ASM_OPERANDS_OUTPUT_CONSTRAINT (x)) - + (unsigned) ASM_OPERANDS_OUTPUT_IDX (x); - - if (ASM_OPERANDS_INPUT_LENGTH (x)) - { - for (i = 1; i < ASM_OPERANDS_INPUT_LENGTH (x); i++) - { - hash += (hash_rtx_cb (ASM_OPERANDS_INPUT (x, i), - GET_MODE (ASM_OPERANDS_INPUT (x, i)), - do_not_record_p, hash_arg_in_memory_p, - have_reg_qty, cb) - + hash_rtx_string - (ASM_OPERANDS_INPUT_CONSTRAINT (x, i))); - } - - hash += hash_rtx_string (ASM_OPERANDS_INPUT_CONSTRAINT (x, 0)); - x = ASM_OPERANDS_INPUT (x, 0); - mode = GET_MODE (x); - goto repeat; - } - - return hash; - } - break; - - default: - break; - } - - i = GET_RTX_LENGTH (code) - 1; - hash += (unsigned) code + (unsigned) GET_MODE (x); - fmt = GET_RTX_FORMAT (code); - for (; i >= 0; i--) - { - switch (fmt[i]) - { - case 'e': - /* If we are about to do the last recursive call - needed at this level, change it into iteration. - This function is called enough to be worth it. */ - if (i == 0) - { - x = XEXP (x, i); - goto repeat; - } - - hash += hash_rtx_cb (XEXP (x, i), VOIDmode, do_not_record_p, - hash_arg_in_memory_p, - have_reg_qty, cb); - break; - - case 'E': - for (j = 0; j < XVECLEN (x, i); j++) - hash += hash_rtx_cb (XVECEXP (x, i, j), VOIDmode, do_not_record_p, - hash_arg_in_memory_p, - have_reg_qty, cb); - break; - - case 's': - hash += hash_rtx_string (XSTR (x, i)); - break; - - case 'i': - hash += (unsigned int) XINT (x, i); - break; - - case '0': case 't': - /* Unused. */ - break; - - default: - gcc_unreachable (); - } - } - - return hash; -} - -/* Hash an rtx. We are careful to make sure the value is never negative. - Equivalent registers hash identically. - MODE is used in hashing for CONST_INTs only; - otherwise the mode of X is used. - - Store 1 in DO_NOT_RECORD_P if any subexpression is volatile. - - If HASH_ARG_IN_MEMORY_P is not NULL, store 1 in it if X contains - a MEM rtx which does not have the MEM_READONLY_P flag set. - - Note that cse_insn knows that the hash code of a MEM expression - is just (int) MEM plus the hash code of the address. */ - -unsigned -hash_rtx (const_rtx x, enum machine_mode mode, int *do_not_record_p, - int *hash_arg_in_memory_p, bool have_reg_qty) -{ - return hash_rtx_cb (x, mode, do_not_record_p, - hash_arg_in_memory_p, have_reg_qty, NULL); -} - -/* Hash an rtx X for cse via hash_rtx. - Stores 1 in do_not_record if any subexpression is volatile. - Stores 1 in hash_arg_in_memory if X contains a mem rtx which - does not have the MEM_READONLY_P flag set. */ - -static inline unsigned -canon_hash (rtx x, enum machine_mode mode) -{ - return hash_rtx (x, mode, &do_not_record, &hash_arg_in_memory, true); -} - -/* Like canon_hash but with no side effects, i.e. do_not_record - and hash_arg_in_memory are not changed. */ - -static inline unsigned -safe_hash (rtx x, enum machine_mode mode) -{ - int dummy_do_not_record; - return hash_rtx (x, mode, &dummy_do_not_record, NULL, true); -} - -/* Return 1 iff X and Y would canonicalize into the same thing, - without actually constructing the canonicalization of either one. - If VALIDATE is nonzero, - we assume X is an expression being processed from the rtl - and Y was found in the hash table. We check register refs - in Y for being marked as valid. - - If FOR_GCSE is true, we compare X and Y for equivalence for GCSE. */ - -int -exp_equiv_p (const_rtx x, const_rtx y, int validate, bool for_gcse) -{ - int i, j; - enum rtx_code code; - const char *fmt; - - /* Note: it is incorrect to assume an expression is equivalent to itself - if VALIDATE is nonzero. */ - if (x == y && !validate) - return 1; - - if (x == 0 || y == 0) - return x == y; - - code = GET_CODE (x); - if (code != GET_CODE (y)) - return 0; - - /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. */ - if (GET_MODE (x) != GET_MODE (y)) - return 0; - - /* MEMs referring to different address space are not equivalent. */ - if (code == MEM && MEM_ADDR_SPACE (x) != MEM_ADDR_SPACE (y)) - return 0; - - switch (code) - { - case PC: - case CC0: - CASE_CONST_UNIQUE: - return x == y; - - case LABEL_REF: - return XEXP (x, 0) == XEXP (y, 0); - - case SYMBOL_REF: - return XSTR (x, 0) == XSTR (y, 0); - - case REG: - if (for_gcse) - return REGNO (x) == REGNO (y); - else - { - unsigned int regno = REGNO (y); - unsigned int i; - unsigned int endregno = END_REGNO (y); - - /* If the quantities are not the same, the expressions are not - equivalent. If there are and we are not to validate, they - are equivalent. Otherwise, ensure all regs are up-to-date. */ - - if (REG_QTY (REGNO (x)) != REG_QTY (regno)) - return 0; - - if (! validate) - return 1; - - for (i = regno; i < endregno; i++) - if (REG_IN_TABLE (i) != REG_TICK (i)) - return 0; - - return 1; - } - - case MEM: - if (for_gcse) - { - /* A volatile mem should not be considered equivalent to any - other. */ - if (MEM_VOLATILE_P (x) || MEM_VOLATILE_P (y)) - return 0; - - /* Can't merge two expressions in different alias sets, since we - can decide that the expression is transparent in a block when - it isn't, due to it being set with the different alias set. - - Also, can't merge two expressions with different MEM_ATTRS. - They could e.g. be two different entities allocated into the - same space on the stack (see e.g. PR25130). In that case, the - MEM addresses can be the same, even though the two MEMs are - absolutely not equivalent. - - But because really all MEM attributes should be the same for - equivalent MEMs, we just use the invariant that MEMs that have - the same attributes share the same mem_attrs data structure. */ - if (MEM_ATTRS (x) != MEM_ATTRS (y)) - return 0; - } - break; - - /* For commutative operations, check both orders. */ - case PLUS: - case MULT: - case AND: - case IOR: - case XOR: - case NE: - case EQ: - return ((exp_equiv_p (XEXP (x, 0), XEXP (y, 0), - validate, for_gcse) - && exp_equiv_p (XEXP (x, 1), XEXP (y, 1), - validate, for_gcse)) - || (exp_equiv_p (XEXP (x, 0), XEXP (y, 1), - validate, for_gcse) - && exp_equiv_p (XEXP (x, 1), XEXP (y, 0), - validate, for_gcse))); - - case ASM_OPERANDS: - /* We don't use the generic code below because we want to - disregard filename and line numbers. */ - - /* A volatile asm isn't equivalent to any other. */ - if (MEM_VOLATILE_P (x) || MEM_VOLATILE_P (y)) - return 0; - - if (GET_MODE (x) != GET_MODE (y) - || strcmp (ASM_OPERANDS_TEMPLATE (x), ASM_OPERANDS_TEMPLATE (y)) - || strcmp (ASM_OPERANDS_OUTPUT_CONSTRAINT (x), - ASM_OPERANDS_OUTPUT_CONSTRAINT (y)) - || ASM_OPERANDS_OUTPUT_IDX (x) != ASM_OPERANDS_OUTPUT_IDX (y) - || ASM_OPERANDS_INPUT_LENGTH (x) != ASM_OPERANDS_INPUT_LENGTH (y)) - return 0; - - if (ASM_OPERANDS_INPUT_LENGTH (x)) - { - for (i = ASM_OPERANDS_INPUT_LENGTH (x) - 1; i >= 0; i--) - if (! exp_equiv_p (ASM_OPERANDS_INPUT (x, i), - ASM_OPERANDS_INPUT (y, i), - validate, for_gcse) - || strcmp (ASM_OPERANDS_INPUT_CONSTRAINT (x, i), - ASM_OPERANDS_INPUT_CONSTRAINT (y, i))) - return 0; - } - - return 1; - - default: - break; - } - - /* Compare the elements. If any pair of corresponding elements - fail to match, return 0 for the whole thing. */ - - fmt = GET_RTX_FORMAT (code); - for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) - { - switch (fmt[i]) - { - case 'e': - if (! exp_equiv_p (XEXP (x, i), XEXP (y, i), - validate, for_gcse)) - return 0; - break; - - case 'E': - if (XVECLEN (x, i) != XVECLEN (y, i)) - return 0; - for (j = 0; j < XVECLEN (x, i); j++) - if (! exp_equiv_p (XVECEXP (x, i, j), XVECEXP (y, i, j), - validate, for_gcse)) - return 0; - break; - - case 's': - if (strcmp (XSTR (x, i), XSTR (y, i))) - return 0; - break; - - case 'i': - if (XINT (x, i) != XINT (y, i)) - return 0; - break; - - case 'w': - if (XWINT (x, i) != XWINT (y, i)) - return 0; - break; - - case '0': - case 't': - break; - - default: - gcc_unreachable (); - } - } - - return 1; -} - -/* Subroutine of canon_reg. Pass *XLOC through canon_reg, and validate - the result if necessary. INSN is as for canon_reg. */ - -static void -validate_canon_reg (rtx *xloc, rtx insn) -{ - if (*xloc) - { - rtx new_rtx = canon_reg (*xloc, insn); - - /* If replacing pseudo with hard reg or vice versa, ensure the - insn remains valid. Likewise if the insn has MATCH_DUPs. */ - gcc_assert (insn && new_rtx); - validate_change (insn, xloc, new_rtx, 1); - } -} - -/* Canonicalize an expression: - replace each register reference inside it - with the "oldest" equivalent register. - - If INSN is nonzero validate_change is used to ensure that INSN remains valid - after we make our substitution. The calls are made with IN_GROUP nonzero - so apply_change_group must be called upon the outermost return from this - function (unless INSN is zero). The result of apply_change_group can - generally be discarded since the changes we are making are optional. */ - -static rtx -canon_reg (rtx x, rtx insn) -{ - int i; - enum rtx_code code; - const char *fmt; - - if (x == 0) - return x; - - code = GET_CODE (x); - switch (code) - { - case PC: - case CC0: - case CONST: - CASE_CONST_ANY: - case SYMBOL_REF: - case LABEL_REF: - case ADDR_VEC: - case ADDR_DIFF_VEC: - return x; - - case REG: - { - int first; - int q; - struct qty_table_elem *ent; - - /* Never replace a hard reg, because hard regs can appear - in more than one machine mode, and we must preserve the mode - of each occurrence. Also, some hard regs appear in - MEMs that are shared and mustn't be altered. Don't try to - replace any reg that maps to a reg of class NO_REGS. */ - if (REGNO (x) < FIRST_PSEUDO_REGISTER - || ! REGNO_QTY_VALID_P (REGNO (x))) - return x; - - q = REG_QTY (REGNO (x)); - ent = &qty_table[q]; - first = ent->first_reg; - return (first >= FIRST_PSEUDO_REGISTER ? regno_reg_rtx[first] - : REGNO_REG_CLASS (first) == NO_REGS ? x - : gen_rtx_REG (ent->mode, first)); - } - - default: - break; - } - - fmt = GET_RTX_FORMAT (code); - for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) - { - int j; - - if (fmt[i] == 'e') - validate_canon_reg (&XEXP (x, i), insn); - else if (fmt[i] == 'E') - for (j = 0; j < XVECLEN (x, i); j++) - validate_canon_reg (&XVECEXP (x, i, j), insn); - } - - return x; -} - -/* Given an operation (CODE, *PARG1, *PARG2), where code is a comparison - operation (EQ, NE, GT, etc.), follow it back through the hash table and - what values are being compared. - - *PARG1 and *PARG2 are updated to contain the rtx representing the values - actually being compared. For example, if *PARG1 was (cc0) and *PARG2 - was (const_int 0), *PARG1 and *PARG2 will be set to the objects that were - compared to produce cc0. - - The return value is the comparison operator and is either the code of - A or the code corresponding to the inverse of the comparison. */ - -static enum rtx_code -find_comparison_args (enum rtx_code code, rtx *parg1, rtx *parg2, - enum machine_mode *pmode1, enum machine_mode *pmode2) -{ - rtx arg1, arg2; - struct pointer_set_t *visited = NULL; - /* Set nonzero when we find something of interest. */ - rtx x = NULL; - - arg1 = *parg1, arg2 = *parg2; - - /* If ARG2 is const0_rtx, see what ARG1 is equivalent to. */ - - while (arg2 == CONST0_RTX (GET_MODE (arg1))) - { - int reverse_code = 0; - struct table_elt *p = 0; - - /* Remember state from previous iteration. */ - if (x) - { - if (!visited) - visited = pointer_set_create (); - pointer_set_insert (visited, x); - x = 0; - } - - /* If arg1 is a COMPARE, extract the comparison arguments from it. - On machines with CC0, this is the only case that can occur, since - fold_rtx will return the COMPARE or item being compared with zero - when given CC0. */ - - if (GET_CODE (arg1) == COMPARE && arg2 == const0_rtx) - x = arg1; - - /* If ARG1 is a comparison operator and CODE is testing for - STORE_FLAG_VALUE, get the inner arguments. */ - - else if (COMPARISON_P (arg1)) - { -#ifdef FLOAT_STORE_FLAG_VALUE - REAL_VALUE_TYPE fsfv; -#endif - - if (code == NE - || (GET_MODE_CLASS (GET_MODE (arg1)) == MODE_INT - && code == LT && STORE_FLAG_VALUE == -1) -#ifdef FLOAT_STORE_FLAG_VALUE - || (SCALAR_FLOAT_MODE_P (GET_MODE (arg1)) - && (fsfv = FLOAT_STORE_FLAG_VALUE (GET_MODE (arg1)), - REAL_VALUE_NEGATIVE (fsfv))) -#endif - ) - x = arg1; - else if (code == EQ - || (GET_MODE_CLASS (GET_MODE (arg1)) == MODE_INT - && code == GE && STORE_FLAG_VALUE == -1) -#ifdef FLOAT_STORE_FLAG_VALUE - || (SCALAR_FLOAT_MODE_P (GET_MODE (arg1)) - && (fsfv = FLOAT_STORE_FLAG_VALUE (GET_MODE (arg1)), - REAL_VALUE_NEGATIVE (fsfv))) -#endif - ) - x = arg1, reverse_code = 1; - } - - /* ??? We could also check for - - (ne (and (eq (...) (const_int 1))) (const_int 0)) - - and related forms, but let's wait until we see them occurring. */ - - if (x == 0) - /* Look up ARG1 in the hash table and see if it has an equivalence - that lets us see what is being compared. */ - p = lookup (arg1, SAFE_HASH (arg1, GET_MODE (arg1)), GET_MODE (arg1)); - if (p) - { - p = p->first_same_value; - - /* If what we compare is already known to be constant, that is as - good as it gets. - We need to break the loop in this case, because otherwise we - can have an infinite loop when looking at a reg that is known - to be a constant which is the same as a comparison of a reg - against zero which appears later in the insn stream, which in - turn is constant and the same as the comparison of the first reg - against zero... */ - if (p->is_const) - break; - } - - for (; p; p = p->next_same_value) - { - enum machine_mode inner_mode = GET_MODE (p->exp); -#ifdef FLOAT_STORE_FLAG_VALUE - REAL_VALUE_TYPE fsfv; -#endif - - /* If the entry isn't valid, skip it. */ - if (! exp_equiv_p (p->exp, p->exp, 1, false)) - continue; - - /* If it's a comparison we've used before, skip it. */ - if (visited && pointer_set_contains (visited, p->exp)) - continue; - - if (GET_CODE (p->exp) == COMPARE - /* Another possibility is that this machine has a compare insn - that includes the comparison code. In that case, ARG1 would - be equivalent to a comparison operation that would set ARG1 to - either STORE_FLAG_VALUE or zero. If this is an NE operation, - ORIG_CODE is the actual comparison being done; if it is an EQ, - we must reverse ORIG_CODE. On machine with a negative value - for STORE_FLAG_VALUE, also look at LT and GE operations. */ - || ((code == NE - || (code == LT - && val_signbit_known_set_p (inner_mode, - STORE_FLAG_VALUE)) -#ifdef FLOAT_STORE_FLAG_VALUE - || (code == LT - && SCALAR_FLOAT_MODE_P (inner_mode) - && (fsfv = FLOAT_STORE_FLAG_VALUE (GET_MODE (arg1)), - REAL_VALUE_NEGATIVE (fsfv))) -#endif - ) - && COMPARISON_P (p->exp))) - { - x = p->exp; - break; - } - else if ((code == EQ - || (code == GE - && val_signbit_known_set_p (inner_mode, - STORE_FLAG_VALUE)) -#ifdef FLOAT_STORE_FLAG_VALUE - || (code == GE - && SCALAR_FLOAT_MODE_P (inner_mode) - && (fsfv = FLOAT_STORE_FLAG_VALUE (GET_MODE (arg1)), - REAL_VALUE_NEGATIVE (fsfv))) -#endif - ) - && COMPARISON_P (p->exp)) - { - reverse_code = 1; - x = p->exp; - break; - } - - /* If this non-trapping address, e.g. fp + constant, the - equivalent is a better operand since it may let us predict - the value of the comparison. */ - else if (!rtx_addr_can_trap_p (p->exp)) - { - arg1 = p->exp; - continue; - } - } - - /* If we didn't find a useful equivalence for ARG1, we are done. - Otherwise, set up for the next iteration. */ - if (x == 0) - break; - - /* If we need to reverse the comparison, make sure that that is - possible -- we can't necessarily infer the value of GE from LT - with floating-point operands. */ - if (reverse_code) - { - enum rtx_code reversed = reversed_comparison_code (x, NULL_RTX); - if (reversed == UNKNOWN) - break; - else - code = reversed; - } - else if (COMPARISON_P (x)) - code = GET_CODE (x); - arg1 = XEXP (x, 0), arg2 = XEXP (x, 1); - } - - /* Return our results. Return the modes from before fold_rtx - because fold_rtx might produce const_int, and then it's too late. */ - *pmode1 = GET_MODE (arg1), *pmode2 = GET_MODE (arg2); - *parg1 = fold_rtx (arg1, 0), *parg2 = fold_rtx (arg2, 0); - - if (visited) - pointer_set_destroy (visited); - return code; -} - -/* If X is a nontrivial arithmetic operation on an argument for which - a constant value can be determined, return the result of operating - on that value, as a constant. Otherwise, return X, possibly with - one or more operands changed to a forward-propagated constant. - - If X is a register whose contents are known, we do NOT return - those contents here; equiv_constant is called to perform that task. - For SUBREGs and MEMs, we do that both here and in equiv_constant. - - INSN is the insn that we may be modifying. If it is 0, make a copy - of X before modifying it. */ - -static rtx -fold_rtx (rtx x, rtx insn) -{ - enum rtx_code code; - enum machine_mode mode; - const char *fmt; - int i; - rtx new_rtx = 0; - int changed = 0; - - /* Operands of X. */ - rtx folded_arg0; - rtx folded_arg1; - - /* Constant equivalents of first three operands of X; - 0 when no such equivalent is known. */ - rtx const_arg0; - rtx const_arg1; - rtx const_arg2; - - /* The mode of the first operand of X. We need this for sign and zero - extends. */ - enum machine_mode mode_arg0; - - if (x == 0) - return x; - - /* Try to perform some initial simplifications on X. */ - code = GET_CODE (x); - switch (code) - { - case MEM: - case SUBREG: - if ((new_rtx = equiv_constant (x)) != NULL_RTX) - return new_rtx; - return x; - - case CONST: - CASE_CONST_ANY: - case SYMBOL_REF: - case LABEL_REF: - case REG: - case PC: - /* No use simplifying an EXPR_LIST - since they are used only for lists of args - in a function call's REG_EQUAL note. */ - case EXPR_LIST: - return x; - -#ifdef HAVE_cc0 - case CC0: - return prev_insn_cc0; -#endif - - case ASM_OPERANDS: - if (insn) - { - for (i = ASM_OPERANDS_INPUT_LENGTH (x) - 1; i >= 0; i--) - validate_change (insn, &ASM_OPERANDS_INPUT (x, i), - fold_rtx (ASM_OPERANDS_INPUT (x, i), insn), 0); - } - return x; - -#ifdef NO_FUNCTION_CSE - case CALL: - if (CONSTANT_P (XEXP (XEXP (x, 0), 0))) - return x; - break; -#endif - - /* Anything else goes through the loop below. */ - default: - break; - } - - mode = GET_MODE (x); - const_arg0 = 0; - const_arg1 = 0; - const_arg2 = 0; - mode_arg0 = VOIDmode; - - /* Try folding our operands. - Then see which ones have constant values known. */ - - fmt = GET_RTX_FORMAT (code); - for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) - if (fmt[i] == 'e') - { - rtx folded_arg = XEXP (x, i), const_arg; - enum machine_mode mode_arg = GET_MODE (folded_arg); - - switch (GET_CODE (folded_arg)) - { - case MEM: - case REG: - case SUBREG: - const_arg = equiv_constant (folded_arg); - break; - - case CONST: - CASE_CONST_ANY: - case SYMBOL_REF: - case LABEL_REF: - const_arg = folded_arg; - break; - -#ifdef HAVE_cc0 - case CC0: - folded_arg = prev_insn_cc0; - mode_arg = prev_insn_cc0_mode; - const_arg = equiv_constant (folded_arg); - break; -#endif - - default: - folded_arg = fold_rtx (folded_arg, insn); - const_arg = equiv_constant (folded_arg); - break; - } - - /* For the first three operands, see if the operand - is constant or equivalent to a constant. */ - switch (i) - { - case 0: - folded_arg0 = folded_arg; - const_arg0 = const_arg; - mode_arg0 = mode_arg; - break; - case 1: - folded_arg1 = folded_arg; - const_arg1 = const_arg; - break; - case 2: - const_arg2 = const_arg; - break; - } - - /* Pick the least expensive of the argument and an equivalent constant - argument. */ - if (const_arg != 0 - && const_arg != folded_arg - && COST_IN (const_arg, code, i) <= COST_IN (folded_arg, code, i) - - /* It's not safe to substitute the operand of a conversion - operator with a constant, as the conversion's identity - depends upon the mode of its operand. This optimization - is handled by the call to simplify_unary_operation. */ - && (GET_RTX_CLASS (code) != RTX_UNARY - || GET_MODE (const_arg) == mode_arg0 - || (code != ZERO_EXTEND - && code != SIGN_EXTEND - && code != TRUNCATE - && code != FLOAT_TRUNCATE - && code != FLOAT_EXTEND - && code != FLOAT - && code != FIX - && code != UNSIGNED_FLOAT - && code != UNSIGNED_FIX))) - folded_arg = const_arg; - - if (folded_arg == XEXP (x, i)) - continue; - - if (insn == NULL_RTX && !changed) - x = copy_rtx (x); - changed = 1; - validate_unshare_change (insn, &XEXP (x, i), folded_arg, 1); - } - - if (changed) - { - /* Canonicalize X if necessary, and keep const_argN and folded_argN - consistent with the order in X. */ - if (canonicalize_change_group (insn, x)) - { - rtx tem; - tem = const_arg0, const_arg0 = const_arg1, const_arg1 = tem; - tem = folded_arg0, folded_arg0 = folded_arg1, folded_arg1 = tem; - } - - apply_change_group (); - } - - /* If X is an arithmetic operation, see if we can simplify it. */ - - switch (GET_RTX_CLASS (code)) - { - case RTX_UNARY: - { - /* We can't simplify extension ops unless we know the - original mode. */ - if ((code == ZERO_EXTEND || code == SIGN_EXTEND) - && mode_arg0 == VOIDmode) - break; - - new_rtx = simplify_unary_operation (code, mode, - const_arg0 ? const_arg0 : folded_arg0, - mode_arg0); - } - break; - - case RTX_COMPARE: - case RTX_COMM_COMPARE: - /* See what items are actually being compared and set FOLDED_ARG[01] - to those values and CODE to the actual comparison code. If any are - constant, set CONST_ARG0 and CONST_ARG1 appropriately. We needn't - do anything if both operands are already known to be constant. */ - - /* ??? Vector mode comparisons are not supported yet. */ - if (VECTOR_MODE_P (mode)) - break; - - if (const_arg0 == 0 || const_arg1 == 0) - { - struct table_elt *p0, *p1; - rtx true_rtx, false_rtx; - enum machine_mode mode_arg1; - - if (SCALAR_FLOAT_MODE_P (mode)) - { -#ifdef FLOAT_STORE_FLAG_VALUE - true_rtx = (CONST_DOUBLE_FROM_REAL_VALUE - (FLOAT_STORE_FLAG_VALUE (mode), mode)); -#else - true_rtx = NULL_RTX; -#endif - false_rtx = CONST0_RTX (mode); - } - else - { - true_rtx = const_true_rtx; - false_rtx = const0_rtx; - } - - code = find_comparison_args (code, &folded_arg0, &folded_arg1, - &mode_arg0, &mode_arg1); - - /* If the mode is VOIDmode or a MODE_CC mode, we don't know - what kinds of things are being compared, so we can't do - anything with this comparison. */ - - if (mode_arg0 == VOIDmode || GET_MODE_CLASS (mode_arg0) == MODE_CC) - break; - - const_arg0 = equiv_constant (folded_arg0); - const_arg1 = equiv_constant (folded_arg1); - - /* If we do not now have two constants being compared, see - if we can nevertheless deduce some things about the - comparison. */ - if (const_arg0 == 0 || const_arg1 == 0) - { - if (const_arg1 != NULL) - { - rtx cheapest_simplification; - int cheapest_cost; - rtx simp_result; - struct table_elt *p; - - /* See if we can find an equivalent of folded_arg0 - that gets us a cheaper expression, possibly a - constant through simplifications. */ - p = lookup (folded_arg0, SAFE_HASH (folded_arg0, mode_arg0), - mode_arg0); - - if (p != NULL) - { - cheapest_simplification = x; - cheapest_cost = COST (x); - - for (p = p->first_same_value; p != NULL; p = p->next_same_value) - { - int cost; - - /* If the entry isn't valid, skip it. */ - if (! exp_equiv_p (p->exp, p->exp, 1, false)) - continue; - - /* Try to simplify using this equivalence. */ - simp_result - = simplify_relational_operation (code, mode, - mode_arg0, - p->exp, - const_arg1); - - if (simp_result == NULL) - continue; - - cost = COST (simp_result); - if (cost < cheapest_cost) - { - cheapest_cost = cost; - cheapest_simplification = simp_result; - } - } - - /* If we have a cheaper expression now, use that - and try folding it further, from the top. */ - if (cheapest_simplification != x) - return fold_rtx (copy_rtx (cheapest_simplification), - insn); - } - } - - /* See if the two operands are the same. */ - - if ((REG_P (folded_arg0) - && REG_P (folded_arg1) - && (REG_QTY (REGNO (folded_arg0)) - == REG_QTY (REGNO (folded_arg1)))) - || ((p0 = lookup (folded_arg0, - SAFE_HASH (folded_arg0, mode_arg0), - mode_arg0)) - && (p1 = lookup (folded_arg1, - SAFE_HASH (folded_arg1, mode_arg0), - mode_arg0)) - && p0->first_same_value == p1->first_same_value)) - folded_arg1 = folded_arg0; - - /* If FOLDED_ARG0 is a register, see if the comparison we are - doing now is either the same as we did before or the reverse - (we only check the reverse if not floating-point). */ - else if (REG_P (folded_arg0)) - { - int qty = REG_QTY (REGNO (folded_arg0)); - - if (REGNO_QTY_VALID_P (REGNO (folded_arg0))) - { - struct qty_table_elem *ent = &qty_table[qty]; - - if ((comparison_dominates_p (ent->comparison_code, code) - || (! FLOAT_MODE_P (mode_arg0) - && comparison_dominates_p (ent->comparison_code, - reverse_condition (code)))) - && (rtx_equal_p (ent->comparison_const, folded_arg1) - || (const_arg1 - && rtx_equal_p (ent->comparison_const, - const_arg1)) - || (REG_P (folded_arg1) - && (REG_QTY (REGNO (folded_arg1)) == ent->comparison_qty)))) - { - if (comparison_dominates_p (ent->comparison_code, code)) - { - if (true_rtx) - return true_rtx; - else - break; - } - else - return false_rtx; - } - } - } - } - } - - /* If we are comparing against zero, see if the first operand is - equivalent to an IOR with a constant. If so, we may be able to - determine the result of this comparison. */ - if (const_arg1 == const0_rtx && !const_arg0) - { - rtx y = lookup_as_function (folded_arg0, IOR); - rtx inner_const; - - if (y != 0 - && (inner_const = equiv_constant (XEXP (y, 1))) != 0 - && CONST_INT_P (inner_const) - && INTVAL (inner_const) != 0) - folded_arg0 = gen_rtx_IOR (mode_arg0, XEXP (y, 0), inner_const); - } - - { - rtx op0 = const_arg0 ? const_arg0 : copy_rtx (folded_arg0); - rtx op1 = const_arg1 ? const_arg1 : copy_rtx (folded_arg1); - new_rtx = simplify_relational_operation (code, mode, mode_arg0, - op0, op1); - } - break; - - case RTX_BIN_ARITH: - case RTX_COMM_ARITH: - switch (code) - { - case PLUS: - /* If the second operand is a LABEL_REF, see if the first is a MINUS - with that LABEL_REF as its second operand. If so, the result is - the first operand of that MINUS. This handles switches with an - ADDR_DIFF_VEC table. */ - if (const_arg1 && GET_CODE (const_arg1) == LABEL_REF) - { - rtx y - = GET_CODE (folded_arg0) == MINUS ? folded_arg0 - : lookup_as_function (folded_arg0, MINUS); - - if (y != 0 && GET_CODE (XEXP (y, 1)) == LABEL_REF - && XEXP (XEXP (y, 1), 0) == XEXP (const_arg1, 0)) - return XEXP (y, 0); - - /* Now try for a CONST of a MINUS like the above. */ - if ((y = (GET_CODE (folded_arg0) == CONST ? folded_arg0 - : lookup_as_function (folded_arg0, CONST))) != 0 - && GET_CODE (XEXP (y, 0)) == MINUS - && GET_CODE (XEXP (XEXP (y, 0), 1)) == LABEL_REF - && XEXP (XEXP (XEXP (y, 0), 1), 0) == XEXP (const_arg1, 0)) - return XEXP (XEXP (y, 0), 0); - } - - /* Likewise if the operands are in the other order. */ - if (const_arg0 && GET_CODE (const_arg0) == LABEL_REF) - { - rtx y - = GET_CODE (folded_arg1) == MINUS ? folded_arg1 - : lookup_as_function (folded_arg1, MINUS); - - if (y != 0 && GET_CODE (XEXP (y, 1)) == LABEL_REF - && XEXP (XEXP (y, 1), 0) == XEXP (const_arg0, 0)) - return XEXP (y, 0); - - /* Now try for a CONST of a MINUS like the above. */ - if ((y = (GET_CODE (folded_arg1) == CONST ? folded_arg1 - : lookup_as_function (folded_arg1, CONST))) != 0 - && GET_CODE (XEXP (y, 0)) == MINUS - && GET_CODE (XEXP (XEXP (y, 0), 1)) == LABEL_REF - && XEXP (XEXP (XEXP (y, 0), 1), 0) == XEXP (const_arg0, 0)) - return XEXP (XEXP (y, 0), 0); - } - - /* If second operand is a register equivalent to a negative - CONST_INT, see if we can find a register equivalent to the - positive constant. Make a MINUS if so. Don't do this for - a non-negative constant since we might then alternate between - choosing positive and negative constants. Having the positive - constant previously-used is the more common case. Be sure - the resulting constant is non-negative; if const_arg1 were - the smallest negative number this would overflow: depending - on the mode, this would either just be the same value (and - hence not save anything) or be incorrect. */ - if (const_arg1 != 0 && CONST_INT_P (const_arg1) - && INTVAL (const_arg1) < 0 - /* This used to test - - -INTVAL (const_arg1) >= 0 - - But The Sun V5.0 compilers mis-compiled that test. So - instead we test for the problematic value in a more direct - manner and hope the Sun compilers get it correct. */ - && INTVAL (const_arg1) != - ((HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT - 1)) - && REG_P (folded_arg1)) - { - rtx new_const = GEN_INT (-INTVAL (const_arg1)); - struct table_elt *p - = lookup (new_const, SAFE_HASH (new_const, mode), mode); - - if (p) - for (p = p->first_same_value; p; p = p->next_same_value) - if (REG_P (p->exp)) - return simplify_gen_binary (MINUS, mode, folded_arg0, - canon_reg (p->exp, NULL_RTX)); - } - goto from_plus; - - case MINUS: - /* If we have (MINUS Y C), see if Y is known to be (PLUS Z C2). - If so, produce (PLUS Z C2-C). */ - if (const_arg1 != 0 && CONST_INT_P (const_arg1)) - { - rtx y = lookup_as_function (XEXP (x, 0), PLUS); - if (y && CONST_INT_P (XEXP (y, 1))) - return fold_rtx (plus_constant (mode, copy_rtx (y), - -INTVAL (const_arg1)), - NULL_RTX); - } - - /* Fall through. */ - - from_plus: - case SMIN: case SMAX: case UMIN: case UMAX: - case IOR: case AND: case XOR: - case MULT: - case ASHIFT: case LSHIFTRT: case ASHIFTRT: - /* If we have (<op> <reg> <const_int>) for an associative OP and REG - is known to be of similar form, we may be able to replace the - operation with a combined operation. This may eliminate the - intermediate operation if every use is simplified in this way. - Note that the similar optimization done by combine.c only works - if the intermediate operation's result has only one reference. */ - - if (REG_P (folded_arg0) - && const_arg1 && CONST_INT_P (const_arg1)) - { - int is_shift - = (code == ASHIFT || code == ASHIFTRT || code == LSHIFTRT); - rtx y, inner_const, new_const; - rtx canon_const_arg1 = const_arg1; - enum rtx_code associate_code; - - if (is_shift - && (INTVAL (const_arg1) >= GET_MODE_PRECISION (mode) - || INTVAL (const_arg1) < 0)) - { - if (SHIFT_COUNT_TRUNCATED) - canon_const_arg1 = GEN_INT (INTVAL (const_arg1) - & (GET_MODE_BITSIZE (mode) - - 1)); - else - break; - } - - y = lookup_as_function (folded_arg0, code); - if (y == 0) - break; - - /* If we have compiled a statement like - "if (x == (x & mask1))", and now are looking at - "x & mask2", we will have a case where the first operand - of Y is the same as our first operand. Unless we detect - this case, an infinite loop will result. */ - if (XEXP (y, 0) == folded_arg0) - break; - - inner_const = equiv_constant (fold_rtx (XEXP (y, 1), 0)); - if (!inner_const || !CONST_INT_P (inner_const)) - break; - - /* Don't associate these operations if they are a PLUS with the - same constant and it is a power of two. These might be doable - with a pre- or post-increment. Similarly for two subtracts of - identical powers of two with post decrement. */ - - if (code == PLUS && const_arg1 == inner_const - && ((HAVE_PRE_INCREMENT - && exact_log2 (INTVAL (const_arg1)) >= 0) - || (HAVE_POST_INCREMENT - && exact_log2 (INTVAL (const_arg1)) >= 0) - || (HAVE_PRE_DECREMENT - && exact_log2 (- INTVAL (const_arg1)) >= 0) - || (HAVE_POST_DECREMENT - && exact_log2 (- INTVAL (const_arg1)) >= 0))) - break; - - /* ??? Vector mode shifts by scalar - shift operand are not supported yet. */ - if (is_shift && VECTOR_MODE_P (mode)) - break; - - if (is_shift - && (INTVAL (inner_const) >= GET_MODE_PRECISION (mode) - || INTVAL (inner_const) < 0)) - { - if (SHIFT_COUNT_TRUNCATED) - inner_const = GEN_INT (INTVAL (inner_const) - & (GET_MODE_BITSIZE (mode) - 1)); - else - break; - } - - /* Compute the code used to compose the constants. For example, - A-C1-C2 is A-(C1 + C2), so if CODE == MINUS, we want PLUS. */ - - associate_code = (is_shift || code == MINUS ? PLUS : code); - - new_const = simplify_binary_operation (associate_code, mode, - canon_const_arg1, - inner_const); - - if (new_const == 0) - break; - - /* If we are associating shift operations, don't let this - produce a shift of the size of the object or larger. - This could occur when we follow a sign-extend by a right - shift on a machine that does a sign-extend as a pair - of shifts. */ - - if (is_shift - && CONST_INT_P (new_const) - && INTVAL (new_const) >= GET_MODE_PRECISION (mode)) - { - /* As an exception, we can turn an ASHIFTRT of this - form into a shift of the number of bits - 1. */ - if (code == ASHIFTRT) - new_const = GEN_INT (GET_MODE_BITSIZE (mode) - 1); - else if (!side_effects_p (XEXP (y, 0))) - return CONST0_RTX (mode); - else - break; - } - - y = copy_rtx (XEXP (y, 0)); - - /* If Y contains our first operand (the most common way this - can happen is if Y is a MEM), we would do into an infinite - loop if we tried to fold it. So don't in that case. */ - - if (! reg_mentioned_p (folded_arg0, y)) - y = fold_rtx (y, insn); - - return simplify_gen_binary (code, mode, y, new_const); - } - break; - - case DIV: case UDIV: - /* ??? The associative optimization performed immediately above is - also possible for DIV and UDIV using associate_code of MULT. - However, we would need extra code to verify that the - multiplication does not overflow, that is, there is no overflow - in the calculation of new_const. */ - break; - - default: - break; - } - - new_rtx = simplify_binary_operation (code, mode, - const_arg0 ? const_arg0 : folded_arg0, - const_arg1 ? const_arg1 : folded_arg1); - break; - - case RTX_OBJ: - /* (lo_sum (high X) X) is simply X. */ - if (code == LO_SUM && const_arg0 != 0 - && GET_CODE (const_arg0) == HIGH - && rtx_equal_p (XEXP (const_arg0, 0), const_arg1)) - return const_arg1; - break; - - case RTX_TERNARY: - case RTX_BITFIELD_OPS: - new_rtx = simplify_ternary_operation (code, mode, mode_arg0, - const_arg0 ? const_arg0 : folded_arg0, - const_arg1 ? const_arg1 : folded_arg1, - const_arg2 ? const_arg2 : XEXP (x, 2)); - break; - - default: - break; - } - - return new_rtx ? new_rtx : x; -} - -/* Return a constant value currently equivalent to X. - Return 0 if we don't know one. */ - -static rtx -equiv_constant (rtx x) -{ - if (REG_P (x) - && REGNO_QTY_VALID_P (REGNO (x))) - { - int x_q = REG_QTY (REGNO (x)); - struct qty_table_elem *x_ent = &qty_table[x_q]; - - if (x_ent->const_rtx) - x = gen_lowpart (GET_MODE (x), x_ent->const_rtx); - } - - if (x == 0 || CONSTANT_P (x)) - return x; - - if (GET_CODE (x) == SUBREG) - { - enum machine_mode mode = GET_MODE (x); - enum machine_mode imode = GET_MODE (SUBREG_REG (x)); - rtx new_rtx; - - /* See if we previously assigned a constant value to this SUBREG. */ - if ((new_rtx = lookup_as_function (x, CONST_INT)) != 0 - || (new_rtx = lookup_as_function (x, CONST_DOUBLE)) != 0 - || (new_rtx = lookup_as_function (x, CONST_FIXED)) != 0) - return new_rtx; - - /* If we didn't and if doing so makes sense, see if we previously - assigned a constant value to the enclosing word mode SUBREG. */ - if (GET_MODE_SIZE (mode) < GET_MODE_SIZE (word_mode) - && GET_MODE_SIZE (word_mode) < GET_MODE_SIZE (imode)) - { - int byte = SUBREG_BYTE (x) - subreg_lowpart_offset (mode, word_mode); - if (byte >= 0 && (byte % UNITS_PER_WORD) == 0) - { - rtx y = gen_rtx_SUBREG (word_mode, SUBREG_REG (x), byte); - new_rtx = lookup_as_function (y, CONST_INT); - if (new_rtx) - return gen_lowpart (mode, new_rtx); - } - } - - /* Otherwise see if we already have a constant for the inner REG, - and if that is enough to calculate an equivalent constant for - the subreg. Note that the upper bits of paradoxical subregs - are undefined, so they cannot be said to equal anything. */ - if (REG_P (SUBREG_REG (x)) - && GET_MODE_SIZE (mode) <= GET_MODE_SIZE (imode) - && (new_rtx = equiv_constant (SUBREG_REG (x))) != 0) - return simplify_subreg (mode, new_rtx, imode, SUBREG_BYTE (x)); - - return 0; - } - - /* If X is a MEM, see if it is a constant-pool reference, or look it up in - the hash table in case its value was seen before. */ - - if (MEM_P (x)) - { - struct table_elt *elt; - - x = avoid_constant_pool_reference (x); - if (CONSTANT_P (x)) - return x; - - elt = lookup (x, SAFE_HASH (x, GET_MODE (x)), GET_MODE (x)); - if (elt == 0) - return 0; - - for (elt = elt->first_same_value; elt; elt = elt->next_same_value) - if (elt->is_const && CONSTANT_P (elt->exp)) - return elt->exp; - } - - return 0; -} - -/* Given INSN, a jump insn, TAKEN indicates if we are following the - "taken" branch. - - In certain cases, this can cause us to add an equivalence. For example, - if we are following the taken case of - if (i == 2) - we can add the fact that `i' and '2' are now equivalent. - - In any case, we can record that this comparison was passed. If the same - comparison is seen later, we will know its value. */ - -static void -record_jump_equiv (rtx insn, bool taken) -{ - int cond_known_true; - rtx op0, op1; - rtx set; - enum machine_mode mode, mode0, mode1; - int reversed_nonequality = 0; - enum rtx_code code; - - /* Ensure this is the right kind of insn. */ - gcc_assert (any_condjump_p (insn)); - - set = pc_set (insn); - - /* See if this jump condition is known true or false. */ - if (taken) - cond_known_true = (XEXP (SET_SRC (set), 2) == pc_rtx); - else - cond_known_true = (XEXP (SET_SRC (set), 1) == pc_rtx); - - /* Get the type of comparison being done and the operands being compared. - If we had to reverse a non-equality condition, record that fact so we - know that it isn't valid for floating-point. */ - code = GET_CODE (XEXP (SET_SRC (set), 0)); - op0 = fold_rtx (XEXP (XEXP (SET_SRC (set), 0), 0), insn); - op1 = fold_rtx (XEXP (XEXP (SET_SRC (set), 0), 1), insn); - - code = find_comparison_args (code, &op0, &op1, &mode0, &mode1); - if (! cond_known_true) - { - code = reversed_comparison_code_parts (code, op0, op1, insn); - - /* Don't remember if we can't find the inverse. */ - if (code == UNKNOWN) - return; - } - - /* The mode is the mode of the non-constant. */ - mode = mode0; - if (mode1 != VOIDmode) - mode = mode1; - - record_jump_cond (code, mode, op0, op1, reversed_nonequality); -} - -/* Yet another form of subreg creation. In this case, we want something in - MODE, and we should assume OP has MODE iff it is naturally modeless. */ - -static rtx -record_jump_cond_subreg (enum machine_mode mode, rtx op) -{ - enum machine_mode op_mode = GET_MODE (op); - if (op_mode == mode || op_mode == VOIDmode) - return op; - return lowpart_subreg (mode, op, op_mode); -} - -/* We know that comparison CODE applied to OP0 and OP1 in MODE is true. - REVERSED_NONEQUALITY is nonzero if CODE had to be swapped. - Make any useful entries we can with that information. Called from - above function and called recursively. */ - -static void -record_jump_cond (enum rtx_code code, enum machine_mode mode, rtx op0, - rtx op1, int reversed_nonequality) -{ - unsigned op0_hash, op1_hash; - int op0_in_memory, op1_in_memory; - struct table_elt *op0_elt, *op1_elt; - - /* If OP0 and OP1 are known equal, and either is a paradoxical SUBREG, - we know that they are also equal in the smaller mode (this is also - true for all smaller modes whether or not there is a SUBREG, but - is not worth testing for with no SUBREG). */ - - /* Note that GET_MODE (op0) may not equal MODE. */ - if (code == EQ && paradoxical_subreg_p (op0)) - { - enum machine_mode inner_mode = GET_MODE (SUBREG_REG (op0)); - rtx tem = record_jump_cond_subreg (inner_mode, op1); - if (tem) - record_jump_cond (code, mode, SUBREG_REG (op0), tem, - reversed_nonequality); - } - - if (code == EQ && paradoxical_subreg_p (op1)) - { - enum machine_mode inner_mode = GET_MODE (SUBREG_REG (op1)); - rtx tem = record_jump_cond_subreg (inner_mode, op0); - if (tem) - record_jump_cond (code, mode, SUBREG_REG (op1), tem, - reversed_nonequality); - } - - /* Similarly, if this is an NE comparison, and either is a SUBREG - making a smaller mode, we know the whole thing is also NE. */ - - /* Note that GET_MODE (op0) may not equal MODE; - if we test MODE instead, we can get an infinite recursion - alternating between two modes each wider than MODE. */ - - if (code == NE && GET_CODE (op0) == SUBREG - && subreg_lowpart_p (op0) - && (GET_MODE_SIZE (GET_MODE (op0)) - < GET_MODE_SIZE (GET_MODE (SUBREG_REG (op0))))) - { - enum machine_mode inner_mode = GET_MODE (SUBREG_REG (op0)); - rtx tem = record_jump_cond_subreg (inner_mode, op1); - if (tem) - record_jump_cond (code, mode, SUBREG_REG (op0), tem, - reversed_nonequality); - } - - if (code == NE && GET_CODE (op1) == SUBREG - && subreg_lowpart_p (op1) - && (GET_MODE_SIZE (GET_MODE (op1)) - < GET_MODE_SIZE (GET_MODE (SUBREG_REG (op1))))) - { - enum machine_mode inner_mode = GET_MODE (SUBREG_REG (op1)); - rtx tem = record_jump_cond_subreg (inner_mode, op0); - if (tem) - record_jump_cond (code, mode, SUBREG_REG (op1), tem, - reversed_nonequality); - } - - /* Hash both operands. */ - - do_not_record = 0; - hash_arg_in_memory = 0; - op0_hash = HASH (op0, mode); - op0_in_memory = hash_arg_in_memory; - - if (do_not_record) - return; - - do_not_record = 0; - hash_arg_in_memory = 0; - op1_hash = HASH (op1, mode); - op1_in_memory = hash_arg_in_memory; - - if (do_not_record) - return; - - /* Look up both operands. */ - op0_elt = lookup (op0, op0_hash, mode); - op1_elt = lookup (op1, op1_hash, mode); - - /* If both operands are already equivalent or if they are not in the - table but are identical, do nothing. */ - if ((op0_elt != 0 && op1_elt != 0 - && op0_elt->first_same_value == op1_elt->first_same_value) - || op0 == op1 || rtx_equal_p (op0, op1)) - return; - - /* If we aren't setting two things equal all we can do is save this - comparison. Similarly if this is floating-point. In the latter - case, OP1 might be zero and both -0.0 and 0.0 are equal to it. - If we record the equality, we might inadvertently delete code - whose intent was to change -0 to +0. */ - - if (code != EQ || FLOAT_MODE_P (GET_MODE (op0))) - { - struct qty_table_elem *ent; - int qty; - - /* If we reversed a floating-point comparison, if OP0 is not a - register, or if OP1 is neither a register or constant, we can't - do anything. */ - - if (!REG_P (op1)) - op1 = equiv_constant (op1); - - if ((reversed_nonequality && FLOAT_MODE_P (mode)) - || !REG_P (op0) || op1 == 0) - return; - - /* Put OP0 in the hash table if it isn't already. This gives it a - new quantity number. */ - if (op0_elt == 0) - { - if (insert_regs (op0, NULL, 0)) - { - rehash_using_reg (op0); - op0_hash = HASH (op0, mode); - - /* If OP0 is contained in OP1, this changes its hash code - as well. Faster to rehash than to check, except - for the simple case of a constant. */ - if (! CONSTANT_P (op1)) - op1_hash = HASH (op1,mode); - } - - op0_elt = insert (op0, NULL, op0_hash, mode); - op0_elt->in_memory = op0_in_memory; - } - - qty = REG_QTY (REGNO (op0)); - ent = &qty_table[qty]; - - ent->comparison_code = code; - if (REG_P (op1)) - { - /* Look it up again--in case op0 and op1 are the same. */ - op1_elt = lookup (op1, op1_hash, mode); - - /* Put OP1 in the hash table so it gets a new quantity number. */ - if (op1_elt == 0) - { - if (insert_regs (op1, NULL, 0)) - { - rehash_using_reg (op1); - op1_hash = HASH (op1, mode); - } - - op1_elt = insert (op1, NULL, op1_hash, mode); - op1_elt->in_memory = op1_in_memory; - } - - ent->comparison_const = NULL_RTX; - ent->comparison_qty = REG_QTY (REGNO (op1)); - } - else - { - ent->comparison_const = op1; - ent->comparison_qty = -1; - } - - return; - } - - /* If either side is still missing an equivalence, make it now, - then merge the equivalences. */ - - if (op0_elt == 0) - { - if (insert_regs (op0, NULL, 0)) - { - rehash_using_reg (op0); - op0_hash = HASH (op0, mode); - } - - op0_elt = insert (op0, NULL, op0_hash, mode); - op0_elt->in_memory = op0_in_memory; - } - - if (op1_elt == 0) - { - if (insert_regs (op1, NULL, 0)) - { - rehash_using_reg (op1); - op1_hash = HASH (op1, mode); - } - - op1_elt = insert (op1, NULL, op1_hash, mode); - op1_elt->in_memory = op1_in_memory; - } - - merge_equiv_classes (op0_elt, op1_elt); -} - -/* CSE processing for one instruction. - - Most "true" common subexpressions are mostly optimized away in GIMPLE, - but the few that "leak through" are cleaned up by cse_insn, and complex - addressing modes are often formed here. - - The main function is cse_insn, and between here and that function - a couple of helper functions is defined to keep the size of cse_insn - within reasonable proportions. - - Data is shared between the main and helper functions via STRUCT SET, - that contains all data related for every set in the instruction that - is being processed. - - Note that cse_main processes all sets in the instruction. Most - passes in GCC only process simple SET insns or single_set insns, but - CSE processes insns with multiple sets as well. */ - -/* Data on one SET contained in the instruction. */ - -struct set -{ - /* The SET rtx itself. */ - rtx rtl; - /* The SET_SRC of the rtx (the original value, if it is changing). */ - rtx src; - /* The hash-table element for the SET_SRC of the SET. */ - struct table_elt *src_elt; - /* Hash value for the SET_SRC. */ - unsigned src_hash; - /* Hash value for the SET_DEST. */ - unsigned dest_hash; - /* The SET_DEST, with SUBREG, etc., stripped. */ - rtx inner_dest; - /* Nonzero if the SET_SRC is in memory. */ - char src_in_memory; - /* Nonzero if the SET_SRC contains something - whose value cannot be predicted and understood. */ - char src_volatile; - /* Original machine mode, in case it becomes a CONST_INT. - The size of this field should match the size of the mode - field of struct rtx_def (see rtl.h). */ - ENUM_BITFIELD(machine_mode) mode : 8; - /* A constant equivalent for SET_SRC, if any. */ - rtx src_const; - /* Hash value of constant equivalent for SET_SRC. */ - unsigned src_const_hash; - /* Table entry for constant equivalent for SET_SRC, if any. */ - struct table_elt *src_const_elt; - /* Table entry for the destination address. */ - struct table_elt *dest_addr_elt; -}; - -/* Special handling for (set REG0 REG1) where REG0 is the - "cheapest", cheaper than REG1. After cse, REG1 will probably not - be used in the sequel, so (if easily done) change this insn to - (set REG1 REG0) and replace REG1 with REG0 in the previous insn - that computed their value. Then REG1 will become a dead store - and won't cloud the situation for later optimizations. - - Do not make this change if REG1 is a hard register, because it will - then be used in the sequel and we may be changing a two-operand insn - into a three-operand insn. - - This is the last transformation that cse_insn will try to do. */ - -static void -try_back_substitute_reg (rtx set, rtx insn) -{ - rtx dest = SET_DEST (set); - rtx src = SET_SRC (set); - - if (REG_P (dest) - && REG_P (src) && ! HARD_REGISTER_P (src) - && REGNO_QTY_VALID_P (REGNO (src))) - { - int src_q = REG_QTY (REGNO (src)); - struct qty_table_elem *src_ent = &qty_table[src_q]; - - if (src_ent->first_reg == REGNO (dest)) - { - /* Scan for the previous nonnote insn, but stop at a basic - block boundary. */ - rtx prev = insn; - rtx bb_head = BB_HEAD (BLOCK_FOR_INSN (insn)); - do - { - prev = PREV_INSN (prev); - } - while (prev != bb_head && (NOTE_P (prev) || DEBUG_INSN_P (prev))); - - /* Do not swap the registers around if the previous instruction - attaches a REG_EQUIV note to REG1. - - ??? It's not entirely clear whether we can transfer a REG_EQUIV - from the pseudo that originally shadowed an incoming argument - to another register. Some uses of REG_EQUIV might rely on it - being attached to REG1 rather than REG2. - - This section previously turned the REG_EQUIV into a REG_EQUAL - note. We cannot do that because REG_EQUIV may provide an - uninitialized stack slot when REG_PARM_STACK_SPACE is used. */ - if (NONJUMP_INSN_P (prev) - && GET_CODE (PATTERN (prev)) == SET - && SET_DEST (PATTERN (prev)) == src - && ! find_reg_note (prev, REG_EQUIV, NULL_RTX)) - { - rtx note; - - validate_change (prev, &SET_DEST (PATTERN (prev)), dest, 1); - validate_change (insn, &SET_DEST (set), src, 1); - validate_change (insn, &SET_SRC (set), dest, 1); - apply_change_group (); - - /* If INSN has a REG_EQUAL note, and this note mentions - REG0, then we must delete it, because the value in - REG0 has changed. If the note's value is REG1, we must - also delete it because that is now this insn's dest. */ - note = find_reg_note (insn, REG_EQUAL, NULL_RTX); - if (note != 0 - && (reg_mentioned_p (dest, XEXP (note, 0)) - || rtx_equal_p (src, XEXP (note, 0)))) - remove_note (insn, note); - } - } - } -} - -/* Record all the SETs in this instruction into SETS_PTR, - and return the number of recorded sets. */ -static int -find_sets_in_insn (rtx insn, struct set **psets) -{ - struct set *sets = *psets; - int n_sets = 0; - rtx x = PATTERN (insn); - - if (GET_CODE (x) == SET) - { - /* Ignore SETs that are unconditional jumps. - They never need cse processing, so this does not hurt. - The reason is not efficiency but rather - so that we can test at the end for instructions - that have been simplified to unconditional jumps - and not be misled by unchanged instructions - that were unconditional jumps to begin with. */ - if (SET_DEST (x) == pc_rtx - && GET_CODE (SET_SRC (x)) == LABEL_REF) - ; - /* Don't count call-insns, (set (reg 0) (call ...)), as a set. - The hard function value register is used only once, to copy to - someplace else, so it isn't worth cse'ing. */ - else if (GET_CODE (SET_SRC (x)) == CALL) - ; - else - sets[n_sets++].rtl = x; - } - else if (GET_CODE (x) == PARALLEL) - { - int i, lim = XVECLEN (x, 0); - - /* Go over the epressions of the PARALLEL in forward order, to - put them in the same order in the SETS array. */ - for (i = 0; i < lim; i++) - { - rtx y = XVECEXP (x, 0, i); - if (GET_CODE (y) == SET) - { - /* As above, we ignore unconditional jumps and call-insns and - ignore the result of apply_change_group. */ - if (SET_DEST (y) == pc_rtx - && GET_CODE (SET_SRC (y)) == LABEL_REF) - ; - else if (GET_CODE (SET_SRC (y)) == CALL) - ; - else - sets[n_sets++].rtl = y; - } - } - } - - return n_sets; -} - -/* Where possible, substitute every register reference in the N_SETS - number of SETS in INSN with the the canonical register. - - Register canonicalization propagatest the earliest register (i.e. - one that is set before INSN) with the same value. This is a very - useful, simple form of CSE, to clean up warts from expanding GIMPLE - to RTL. For instance, a CONST for an address is usually expanded - multiple times to loads into different registers, thus creating many - subexpressions of the form: - - (set (reg1) (some_const)) - (set (mem (... reg1 ...) (thing))) - (set (reg2) (some_const)) - (set (mem (... reg2 ...) (thing))) - - After canonicalizing, the code takes the following form: - - (set (reg1) (some_const)) - (set (mem (... reg1 ...) (thing))) - (set (reg2) (some_const)) - (set (mem (... reg1 ...) (thing))) - - The set to reg2 is now trivially dead, and the memory reference (or - address, or whatever) may be a candidate for further CSEing. - - In this function, the result of apply_change_group can be ignored; - see canon_reg. */ - -static void -canonicalize_insn (rtx insn, struct set **psets, int n_sets) -{ - struct set *sets = *psets; - rtx tem; - rtx x = PATTERN (insn); - int i; - - if (CALL_P (insn)) - { - for (tem = CALL_INSN_FUNCTION_USAGE (insn); tem; tem = XEXP (tem, 1)) - if (GET_CODE (XEXP (tem, 0)) != SET) - XEXP (tem, 0) = canon_reg (XEXP (tem, 0), insn); - } - - if (GET_CODE (x) == SET && GET_CODE (SET_SRC (x)) == CALL) - { - canon_reg (SET_SRC (x), insn); - apply_change_group (); - fold_rtx (SET_SRC (x), insn); - } - else if (GET_CODE (x) == CLOBBER) - { - /* If we clobber memory, canon the address. - This does nothing when a register is clobbered - because we have already invalidated the reg. */ - if (MEM_P (XEXP (x, 0))) - canon_reg (XEXP (x, 0), insn); - } - else if (GET_CODE (x) == USE - && ! (REG_P (XEXP (x, 0)) - && REGNO (XEXP (x, 0)) < FIRST_PSEUDO_REGISTER)) - /* Canonicalize a USE of a pseudo register or memory location. */ - canon_reg (x, insn); - else if (GET_CODE (x) == ASM_OPERANDS) - { - for (i = ASM_OPERANDS_INPUT_LENGTH (x) - 1; i >= 0; i--) - { - rtx input = ASM_OPERANDS_INPUT (x, i); - if (!(REG_P (input) && REGNO (input) < FIRST_PSEUDO_REGISTER)) - { - input = canon_reg (input, insn); - validate_change (insn, &ASM_OPERANDS_INPUT (x, i), input, 1); - } - } - } - else if (GET_CODE (x) == CALL) - { - canon_reg (x, insn); - apply_change_group (); - fold_rtx (x, insn); - } - else if (DEBUG_INSN_P (insn)) - canon_reg (PATTERN (insn), insn); - else if (GET_CODE (x) == PARALLEL) - { - for (i = XVECLEN (x, 0) - 1; i >= 0; i--) - { - rtx y = XVECEXP (x, 0, i); - if (GET_CODE (y) == SET && GET_CODE (SET_SRC (y)) == CALL) - { - canon_reg (SET_SRC (y), insn); - apply_change_group (); - fold_rtx (SET_SRC (y), insn); - } - else if (GET_CODE (y) == CLOBBER) - { - if (MEM_P (XEXP (y, 0))) - canon_reg (XEXP (y, 0), insn); - } - else if (GET_CODE (y) == USE - && ! (REG_P (XEXP (y, 0)) - && REGNO (XEXP (y, 0)) < FIRST_PSEUDO_REGISTER)) - canon_reg (y, insn); - else if (GET_CODE (y) == CALL) - { - canon_reg (y, insn); - apply_change_group (); - fold_rtx (y, insn); - } - } - } - - if (n_sets == 1 && REG_NOTES (insn) != 0 - && (tem = find_reg_note (insn, REG_EQUAL, NULL_RTX)) != 0) - { - /* We potentially will process this insn many times. Therefore, - drop the REG_EQUAL note if it is equal to the SET_SRC of the - unique set in INSN. - - Do not do so if the REG_EQUAL note is for a STRICT_LOW_PART, - because cse_insn handles those specially. */ - if (GET_CODE (SET_DEST (sets[0].rtl)) != STRICT_LOW_PART - && rtx_equal_p (XEXP (tem, 0), SET_SRC (sets[0].rtl))) - remove_note (insn, tem); - else - { - canon_reg (XEXP (tem, 0), insn); - apply_change_group (); - XEXP (tem, 0) = fold_rtx (XEXP (tem, 0), insn); - df_notes_rescan (insn); - } - } - - /* Canonicalize sources and addresses of destinations. - We do this in a separate pass to avoid problems when a MATCH_DUP is - present in the insn pattern. In that case, we want to ensure that - we don't break the duplicate nature of the pattern. So we will replace - both operands at the same time. Otherwise, we would fail to find an - equivalent substitution in the loop calling validate_change below. - - We used to suppress canonicalization of DEST if it appears in SRC, - but we don't do this any more. */ - - for (i = 0; i < n_sets; i++) - { - rtx dest = SET_DEST (sets[i].rtl); - rtx src = SET_SRC (sets[i].rtl); - rtx new_rtx = canon_reg (src, insn); - - validate_change (insn, &SET_SRC (sets[i].rtl), new_rtx, 1); - - if (GET_CODE (dest) == ZERO_EXTRACT) - { - validate_change (insn, &XEXP (dest, 1), - canon_reg (XEXP (dest, 1), insn), 1); - validate_change (insn, &XEXP (dest, 2), - canon_reg (XEXP (dest, 2), insn), 1); - } - - while (GET_CODE (dest) == SUBREG - || GET_CODE (dest) == ZERO_EXTRACT - || GET_CODE (dest) == STRICT_LOW_PART) - dest = XEXP (dest, 0); - - if (MEM_P (dest)) - canon_reg (dest, insn); - } - - /* Now that we have done all the replacements, we can apply the change - group and see if they all work. Note that this will cause some - canonicalizations that would have worked individually not to be applied - because some other canonicalization didn't work, but this should not - occur often. - - The result of apply_change_group can be ignored; see canon_reg. */ - - apply_change_group (); -} - -/* Main function of CSE. - First simplify sources and addresses of all assignments - in the instruction, using previously-computed equivalents values. - Then install the new sources and destinations in the table - of available values. */ - -static void -cse_insn (rtx insn) -{ - rtx x = PATTERN (insn); - int i; - rtx tem; - int n_sets = 0; - - rtx src_eqv = 0; - struct table_elt *src_eqv_elt = 0; - int src_eqv_volatile = 0; - int src_eqv_in_memory = 0; - unsigned src_eqv_hash = 0; - - struct set *sets = (struct set *) 0; - - if (GET_CODE (x) == SET) - sets = XALLOCA (struct set); - else if (GET_CODE (x) == PARALLEL) - sets = XALLOCAVEC (struct set, XVECLEN (x, 0)); - - this_insn = insn; -#ifdef HAVE_cc0 - /* Records what this insn does to set CC0. */ - this_insn_cc0 = 0; - this_insn_cc0_mode = VOIDmode; -#endif - - /* Find all regs explicitly clobbered in this insn, - to ensure they are not replaced with any other regs - elsewhere in this insn. */ - invalidate_from_sets_and_clobbers (insn); - - /* Record all the SETs in this instruction. */ - n_sets = find_sets_in_insn (insn, &sets); - - /* Substitute the canonical register where possible. */ - canonicalize_insn (insn, &sets, n_sets); - - /* If this insn has a REG_EQUAL note, store the equivalent value in SRC_EQV, - if different, or if the DEST is a STRICT_LOW_PART. The latter condition - is necessary because SRC_EQV is handled specially for this case, and if - it isn't set, then there will be no equivalence for the destination. */ - if (n_sets == 1 && REG_NOTES (insn) != 0 - && (tem = find_reg_note (insn, REG_EQUAL, NULL_RTX)) != 0 - && (! rtx_equal_p (XEXP (tem, 0), SET_SRC (sets[0].rtl)) - || GET_CODE (SET_DEST (sets[0].rtl)) == STRICT_LOW_PART)) - src_eqv = copy_rtx (XEXP (tem, 0)); - - /* Set sets[i].src_elt to the class each source belongs to. - Detect assignments from or to volatile things - and set set[i] to zero so they will be ignored - in the rest of this function. - - Nothing in this loop changes the hash table or the register chains. */ - - for (i = 0; i < n_sets; i++) - { - bool repeat = false; - rtx src, dest; - rtx src_folded; - struct table_elt *elt = 0, *p; - enum machine_mode mode; - rtx src_eqv_here; - rtx src_const = 0; - rtx src_related = 0; - bool src_related_is_const_anchor = false; - struct table_elt *src_const_elt = 0; - int src_cost = MAX_COST; - int src_eqv_cost = MAX_COST; - int src_folded_cost = MAX_COST; - int src_related_cost = MAX_COST; - int src_elt_cost = MAX_COST; - int src_regcost = MAX_COST; - int src_eqv_regcost = MAX_COST; - int src_folded_regcost = MAX_COST; - int src_related_regcost = MAX_COST; - int src_elt_regcost = MAX_COST; - /* Set nonzero if we need to call force_const_mem on with the - contents of src_folded before using it. */ - int src_folded_force_flag = 0; - - dest = SET_DEST (sets[i].rtl); - src = SET_SRC (sets[i].rtl); - - /* If SRC is a constant that has no machine mode, - hash it with the destination's machine mode. - This way we can keep different modes separate. */ - - mode = GET_MODE (src) == VOIDmode ? GET_MODE (dest) : GET_MODE (src); - sets[i].mode = mode; - - if (src_eqv) - { - enum machine_mode eqvmode = mode; - if (GET_CODE (dest) == STRICT_LOW_PART) - eqvmode = GET_MODE (SUBREG_REG (XEXP (dest, 0))); - do_not_record = 0; - hash_arg_in_memory = 0; - src_eqv_hash = HASH (src_eqv, eqvmode); - - /* Find the equivalence class for the equivalent expression. */ - - if (!do_not_record) - src_eqv_elt = lookup (src_eqv, src_eqv_hash, eqvmode); - - src_eqv_volatile = do_not_record; - src_eqv_in_memory = hash_arg_in_memory; - } - - /* If this is a STRICT_LOW_PART assignment, src_eqv corresponds to the - value of the INNER register, not the destination. So it is not - a valid substitution for the source. But save it for later. */ - if (GET_CODE (dest) == STRICT_LOW_PART) - src_eqv_here = 0; - else - src_eqv_here = src_eqv; - - /* Simplify and foldable subexpressions in SRC. Then get the fully- - simplified result, which may not necessarily be valid. */ - src_folded = fold_rtx (src, insn); - -#if 0 - /* ??? This caused bad code to be generated for the m68k port with -O2. - Suppose src is (CONST_INT -1), and that after truncation src_folded - is (CONST_INT 3). Suppose src_folded is then used for src_const. - At the end we will add src and src_const to the same equivalence - class. We now have 3 and -1 on the same equivalence class. This - causes later instructions to be mis-optimized. */ - /* If storing a constant in a bitfield, pre-truncate the constant - so we will be able to record it later. */ - if (GET_CODE (SET_DEST (sets[i].rtl)) == ZERO_EXTRACT) - { - rtx width = XEXP (SET_DEST (sets[i].rtl), 1); - - if (CONST_INT_P (src) - && CONST_INT_P (width) - && INTVAL (width) < HOST_BITS_PER_WIDE_INT - && (INTVAL (src) & ((HOST_WIDE_INT) (-1) << INTVAL (width)))) - src_folded - = GEN_INT (INTVAL (src) & (((HOST_WIDE_INT) 1 - << INTVAL (width)) - 1)); - } -#endif - - /* Compute SRC's hash code, and also notice if it - should not be recorded at all. In that case, - prevent any further processing of this assignment. */ - do_not_record = 0; - hash_arg_in_memory = 0; - - sets[i].src = src; - sets[i].src_hash = HASH (src, mode); - sets[i].src_volatile = do_not_record; - sets[i].src_in_memory = hash_arg_in_memory; - - /* If SRC is a MEM, there is a REG_EQUIV note for SRC, and DEST is - a pseudo, do not record SRC. Using SRC as a replacement for - anything else will be incorrect in that situation. Note that - this usually occurs only for stack slots, in which case all the - RTL would be referring to SRC, so we don't lose any optimization - opportunities by not having SRC in the hash table. */ - - if (MEM_P (src) - && find_reg_note (insn, REG_EQUIV, NULL_RTX) != 0 - && REG_P (dest) - && REGNO (dest) >= FIRST_PSEUDO_REGISTER) - sets[i].src_volatile = 1; - -#if 0 - /* It is no longer clear why we used to do this, but it doesn't - appear to still be needed. So let's try without it since this - code hurts cse'ing widened ops. */ - /* If source is a paradoxical subreg (such as QI treated as an SI), - treat it as volatile. It may do the work of an SI in one context - where the extra bits are not being used, but cannot replace an SI - in general. */ - if (paradoxical_subreg_p (src)) - sets[i].src_volatile = 1; -#endif - - /* Locate all possible equivalent forms for SRC. Try to replace - SRC in the insn with each cheaper equivalent. - - We have the following types of equivalents: SRC itself, a folded - version, a value given in a REG_EQUAL note, or a value related - to a constant. - - Each of these equivalents may be part of an additional class - of equivalents (if more than one is in the table, they must be in - the same class; we check for this). - - If the source is volatile, we don't do any table lookups. - - We note any constant equivalent for possible later use in a - REG_NOTE. */ - - if (!sets[i].src_volatile) - elt = lookup (src, sets[i].src_hash, mode); - - sets[i].src_elt = elt; - - if (elt && src_eqv_here && src_eqv_elt) - { - if (elt->first_same_value != src_eqv_elt->first_same_value) - { - /* The REG_EQUAL is indicating that two formerly distinct - classes are now equivalent. So merge them. */ - merge_equiv_classes (elt, src_eqv_elt); - src_eqv_hash = HASH (src_eqv, elt->mode); - src_eqv_elt = lookup (src_eqv, src_eqv_hash, elt->mode); - } - - src_eqv_here = 0; - } - - else if (src_eqv_elt) - elt = src_eqv_elt; - - /* Try to find a constant somewhere and record it in `src_const'. - Record its table element, if any, in `src_const_elt'. Look in - any known equivalences first. (If the constant is not in the - table, also set `sets[i].src_const_hash'). */ - if (elt) - for (p = elt->first_same_value; p; p = p->next_same_value) - if (p->is_const) - { - src_const = p->exp; - src_const_elt = elt; - break; - } - - if (src_const == 0 - && (CONSTANT_P (src_folded) - /* Consider (minus (label_ref L1) (label_ref L2)) as - "constant" here so we will record it. This allows us - to fold switch statements when an ADDR_DIFF_VEC is used. */ - || (GET_CODE (src_folded) == MINUS - && GET_CODE (XEXP (src_folded, 0)) == LABEL_REF - && GET_CODE (XEXP (src_folded, 1)) == LABEL_REF))) - src_const = src_folded, src_const_elt = elt; - else if (src_const == 0 && src_eqv_here && CONSTANT_P (src_eqv_here)) - src_const = src_eqv_here, src_const_elt = src_eqv_elt; - - /* If we don't know if the constant is in the table, get its - hash code and look it up. */ - if (src_const && src_const_elt == 0) - { - sets[i].src_const_hash = HASH (src_const, mode); - src_const_elt = lookup (src_const, sets[i].src_const_hash, mode); - } - - sets[i].src_const = src_const; - sets[i].src_const_elt = src_const_elt; - - /* If the constant and our source are both in the table, mark them as - equivalent. Otherwise, if a constant is in the table but the source - isn't, set ELT to it. */ - if (src_const_elt && elt - && src_const_elt->first_same_value != elt->first_same_value) - merge_equiv_classes (elt, src_const_elt); - else if (src_const_elt && elt == 0) - elt = src_const_elt; - - /* See if there is a register linearly related to a constant - equivalent of SRC. */ - if (src_const - && (GET_CODE (src_const) == CONST - || (src_const_elt && src_const_elt->related_value != 0))) - { - src_related = use_related_value (src_const, src_const_elt); - if (src_related) - { - struct table_elt *src_related_elt - = lookup (src_related, HASH (src_related, mode), mode); - if (src_related_elt && elt) - { - if (elt->first_same_value - != src_related_elt->first_same_value) - /* This can occur when we previously saw a CONST - involving a SYMBOL_REF and then see the SYMBOL_REF - twice. Merge the involved classes. */ - merge_equiv_classes (elt, src_related_elt); - - src_related = 0; - src_related_elt = 0; - } - else if (src_related_elt && elt == 0) - elt = src_related_elt; - } - } - - /* See if we have a CONST_INT that is already in a register in a - wider mode. */ - - if (src_const && src_related == 0 && CONST_INT_P (src_const) - && GET_MODE_CLASS (mode) == MODE_INT - && GET_MODE_PRECISION (mode) < BITS_PER_WORD) - { - enum machine_mode wider_mode; - - for (wider_mode = GET_MODE_WIDER_MODE (mode); - wider_mode != VOIDmode - && GET_MODE_PRECISION (wider_mode) <= BITS_PER_WORD - && src_related == 0; - wider_mode = GET_MODE_WIDER_MODE (wider_mode)) - { - struct table_elt *const_elt - = lookup (src_const, HASH (src_const, wider_mode), wider_mode); - - if (const_elt == 0) - continue; - - for (const_elt = const_elt->first_same_value; - const_elt; const_elt = const_elt->next_same_value) - if (REG_P (const_elt->exp)) - { - src_related = gen_lowpart (mode, const_elt->exp); - break; - } - } - } - - /* Another possibility is that we have an AND with a constant in - a mode narrower than a word. If so, it might have been generated - as part of an "if" which would narrow the AND. If we already - have done the AND in a wider mode, we can use a SUBREG of that - value. */ - - if (flag_expensive_optimizations && ! src_related - && GET_CODE (src) == AND && CONST_INT_P (XEXP (src, 1)) - && GET_MODE_SIZE (mode) < UNITS_PER_WORD) - { - enum machine_mode tmode; - rtx new_and = gen_rtx_AND (VOIDmode, NULL_RTX, XEXP (src, 1)); - - for (tmode = GET_MODE_WIDER_MODE (mode); - GET_MODE_SIZE (tmode) <= UNITS_PER_WORD; - tmode = GET_MODE_WIDER_MODE (tmode)) - { - rtx inner = gen_lowpart (tmode, XEXP (src, 0)); - struct table_elt *larger_elt; - - if (inner) - { - PUT_MODE (new_and, tmode); - XEXP (new_and, 0) = inner; - larger_elt = lookup (new_and, HASH (new_and, tmode), tmode); - if (larger_elt == 0) - continue; - - for (larger_elt = larger_elt->first_same_value; - larger_elt; larger_elt = larger_elt->next_same_value) - if (REG_P (larger_elt->exp)) - { - src_related - = gen_lowpart (mode, larger_elt->exp); - break; - } - - if (src_related) - break; - } - } - } - -#ifdef LOAD_EXTEND_OP - /* See if a MEM has already been loaded with a widening operation; - if it has, we can use a subreg of that. Many CISC machines - also have such operations, but this is only likely to be - beneficial on these machines. */ - - if (flag_expensive_optimizations && src_related == 0 - && (GET_MODE_SIZE (mode) < UNITS_PER_WORD) - && GET_MODE_CLASS (mode) == MODE_INT - && MEM_P (src) && ! do_not_record - && LOAD_EXTEND_OP (mode) != UNKNOWN) - { - struct rtx_def memory_extend_buf; - rtx memory_extend_rtx = &memory_extend_buf; - enum machine_mode tmode; - - /* Set what we are trying to extend and the operation it might - have been extended with. */ - memset (memory_extend_rtx, 0, sizeof(*memory_extend_rtx)); - PUT_CODE (memory_extend_rtx, LOAD_EXTEND_OP (mode)); - XEXP (memory_extend_rtx, 0) = src; - - for (tmode = GET_MODE_WIDER_MODE (mode); - GET_MODE_SIZE (tmode) <= UNITS_PER_WORD; - tmode = GET_MODE_WIDER_MODE (tmode)) - { - struct table_elt *larger_elt; - - PUT_MODE (memory_extend_rtx, tmode); - larger_elt = lookup (memory_extend_rtx, - HASH (memory_extend_rtx, tmode), tmode); - if (larger_elt == 0) - continue; - - for (larger_elt = larger_elt->first_same_value; - larger_elt; larger_elt = larger_elt->next_same_value) - if (REG_P (larger_elt->exp)) - { - src_related = gen_lowpart (mode, larger_elt->exp); - break; - } - - if (src_related) - break; - } - } -#endif /* LOAD_EXTEND_OP */ - - /* Try to express the constant using a register+offset expression - derived from a constant anchor. */ - - if (targetm.const_anchor - && !src_related - && src_const - && GET_CODE (src_const) == CONST_INT) - { - src_related = try_const_anchors (src_const, mode); - src_related_is_const_anchor = src_related != NULL_RTX; - } - - - if (src == src_folded) - src_folded = 0; - - /* At this point, ELT, if nonzero, points to a class of expressions - equivalent to the source of this SET and SRC, SRC_EQV, SRC_FOLDED, - and SRC_RELATED, if nonzero, each contain additional equivalent - expressions. Prune these latter expressions by deleting expressions - already in the equivalence class. - - Check for an equivalent identical to the destination. If found, - this is the preferred equivalent since it will likely lead to - elimination of the insn. Indicate this by placing it in - `src_related'. */ - - if (elt) - elt = elt->first_same_value; - for (p = elt; p; p = p->next_same_value) - { - enum rtx_code code = GET_CODE (p->exp); - - /* If the expression is not valid, ignore it. Then we do not - have to check for validity below. In most cases, we can use - `rtx_equal_p', since canonicalization has already been done. */ - if (code != REG && ! exp_equiv_p (p->exp, p->exp, 1, false)) - continue; - - /* Also skip paradoxical subregs, unless that's what we're - looking for. */ - if (paradoxical_subreg_p (p->exp) - && ! (src != 0 - && GET_CODE (src) == SUBREG - && GET_MODE (src) == GET_MODE (p->exp) - && (GET_MODE_SIZE (GET_MODE (SUBREG_REG (src))) - < GET_MODE_SIZE (GET_MODE (SUBREG_REG (p->exp)))))) - continue; - - if (src && GET_CODE (src) == code && rtx_equal_p (src, p->exp)) - src = 0; - else if (src_folded && GET_CODE (src_folded) == code - && rtx_equal_p (src_folded, p->exp)) - src_folded = 0; - else if (src_eqv_here && GET_CODE (src_eqv_here) == code - && rtx_equal_p (src_eqv_here, p->exp)) - src_eqv_here = 0; - else if (src_related && GET_CODE (src_related) == code - && rtx_equal_p (src_related, p->exp)) - src_related = 0; - - /* This is the same as the destination of the insns, we want - to prefer it. Copy it to src_related. The code below will - then give it a negative cost. */ - if (GET_CODE (dest) == code && rtx_equal_p (p->exp, dest)) - src_related = dest; - } - - /* Find the cheapest valid equivalent, trying all the available - possibilities. Prefer items not in the hash table to ones - that are when they are equal cost. Note that we can never - worsen an insn as the current contents will also succeed. - If we find an equivalent identical to the destination, use it as best, - since this insn will probably be eliminated in that case. */ - if (src) - { - if (rtx_equal_p (src, dest)) - src_cost = src_regcost = -1; - else - { - src_cost = COST (src); - src_regcost = approx_reg_cost (src); - } - } - - if (src_eqv_here) - { - if (rtx_equal_p (src_eqv_here, dest)) - src_eqv_cost = src_eqv_regcost = -1; - else - { - src_eqv_cost = COST (src_eqv_here); - src_eqv_regcost = approx_reg_cost (src_eqv_here); - } - } - - if (src_folded) - { - if (rtx_equal_p (src_folded, dest)) - src_folded_cost = src_folded_regcost = -1; - else - { - src_folded_cost = COST (src_folded); - src_folded_regcost = approx_reg_cost (src_folded); - } - } - - if (src_related) - { - if (rtx_equal_p (src_related, dest)) - src_related_cost = src_related_regcost = -1; - else - { - src_related_cost = COST (src_related); - src_related_regcost = approx_reg_cost (src_related); - - /* If a const-anchor is used to synthesize a constant that - normally requires multiple instructions then slightly prefer - it over the original sequence. These instructions are likely - to become redundant now. We can't compare against the cost - of src_eqv_here because, on MIPS for example, multi-insn - constants have zero cost; they are assumed to be hoisted from - loops. */ - if (src_related_is_const_anchor - && src_related_cost == src_cost - && src_eqv_here) - src_related_cost--; - } - } - - /* If this was an indirect jump insn, a known label will really be - cheaper even though it looks more expensive. */ - if (dest == pc_rtx && src_const && GET_CODE (src_const) == LABEL_REF) - src_folded = src_const, src_folded_cost = src_folded_regcost = -1; - - /* Terminate loop when replacement made. This must terminate since - the current contents will be tested and will always be valid. */ - while (1) - { - rtx trial; - - /* Skip invalid entries. */ - while (elt && !REG_P (elt->exp) - && ! exp_equiv_p (elt->exp, elt->exp, 1, false)) - elt = elt->next_same_value; - - /* A paradoxical subreg would be bad here: it'll be the right - size, but later may be adjusted so that the upper bits aren't - what we want. So reject it. */ - if (elt != 0 - && paradoxical_subreg_p (elt->exp) - /* It is okay, though, if the rtx we're trying to match - will ignore any of the bits we can't predict. */ - && ! (src != 0 - && GET_CODE (src) == SUBREG - && GET_MODE (src) == GET_MODE (elt->exp) - && (GET_MODE_SIZE (GET_MODE (SUBREG_REG (src))) - < GET_MODE_SIZE (GET_MODE (SUBREG_REG (elt->exp)))))) - { - elt = elt->next_same_value; - continue; - } - - if (elt) - { - src_elt_cost = elt->cost; - src_elt_regcost = elt->regcost; - } - - /* Find cheapest and skip it for the next time. For items - of equal cost, use this order: - src_folded, src, src_eqv, src_related and hash table entry. */ - if (src_folded - && preferable (src_folded_cost, src_folded_regcost, - src_cost, src_regcost) <= 0 - && preferable (src_folded_cost, src_folded_regcost, - src_eqv_cost, src_eqv_regcost) <= 0 - && preferable (src_folded_cost, src_folded_regcost, - src_related_cost, src_related_regcost) <= 0 - && preferable (src_folded_cost, src_folded_regcost, - src_elt_cost, src_elt_regcost) <= 0) - { - trial = src_folded, src_folded_cost = MAX_COST; - if (src_folded_force_flag) - { - rtx forced = force_const_mem (mode, trial); - if (forced) - trial = forced; - } - } - else if (src - && preferable (src_cost, src_regcost, - src_eqv_cost, src_eqv_regcost) <= 0 - && preferable (src_cost, src_regcost, - src_related_cost, src_related_regcost) <= 0 - && preferable (src_cost, src_regcost, - src_elt_cost, src_elt_regcost) <= 0) - trial = src, src_cost = MAX_COST; - else if (src_eqv_here - && preferable (src_eqv_cost, src_eqv_regcost, - src_related_cost, src_related_regcost) <= 0 - && preferable (src_eqv_cost, src_eqv_regcost, - src_elt_cost, src_elt_regcost) <= 0) - trial = src_eqv_here, src_eqv_cost = MAX_COST; - else if (src_related - && preferable (src_related_cost, src_related_regcost, - src_elt_cost, src_elt_regcost) <= 0) - trial = src_related, src_related_cost = MAX_COST; - else - { - trial = elt->exp; - elt = elt->next_same_value; - src_elt_cost = MAX_COST; - } - - /* Avoid creation of overlapping memory moves. */ - if (MEM_P (trial) && MEM_P (SET_DEST (sets[i].rtl))) - { - rtx src, dest; - - /* BLKmode moves are not handled by cse anyway. */ - if (GET_MODE (trial) == BLKmode) - break; - - src = canon_rtx (trial); - dest = canon_rtx (SET_DEST (sets[i].rtl)); - - if (!MEM_P (src) || !MEM_P (dest) - || !nonoverlapping_memrefs_p (src, dest, false)) - break; - } - - /* Try to optimize - (set (reg:M N) (const_int A)) - (set (reg:M2 O) (const_int B)) - (set (zero_extract:M2 (reg:M N) (const_int C) (const_int D)) - (reg:M2 O)). */ - if (GET_CODE (SET_DEST (sets[i].rtl)) == ZERO_EXTRACT - && CONST_INT_P (trial) - && CONST_INT_P (XEXP (SET_DEST (sets[i].rtl), 1)) - && CONST_INT_P (XEXP (SET_DEST (sets[i].rtl), 2)) - && REG_P (XEXP (SET_DEST (sets[i].rtl), 0)) - && (GET_MODE_PRECISION (GET_MODE (SET_DEST (sets[i].rtl))) - >= INTVAL (XEXP (SET_DEST (sets[i].rtl), 1))) - && ((unsigned) INTVAL (XEXP (SET_DEST (sets[i].rtl), 1)) - + (unsigned) INTVAL (XEXP (SET_DEST (sets[i].rtl), 2)) - <= HOST_BITS_PER_WIDE_INT)) - { - rtx dest_reg = XEXP (SET_DEST (sets[i].rtl), 0); - rtx width = XEXP (SET_DEST (sets[i].rtl), 1); - rtx pos = XEXP (SET_DEST (sets[i].rtl), 2); - unsigned int dest_hash = HASH (dest_reg, GET_MODE (dest_reg)); - struct table_elt *dest_elt - = lookup (dest_reg, dest_hash, GET_MODE (dest_reg)); - rtx dest_cst = NULL; - - if (dest_elt) - for (p = dest_elt->first_same_value; p; p = p->next_same_value) - if (p->is_const && CONST_INT_P (p->exp)) - { - dest_cst = p->exp; - break; - } - if (dest_cst) - { - HOST_WIDE_INT val = INTVAL (dest_cst); - HOST_WIDE_INT mask; - unsigned int shift; - if (BITS_BIG_ENDIAN) - shift = GET_MODE_PRECISION (GET_MODE (dest_reg)) - - INTVAL (pos) - INTVAL (width); - else - shift = INTVAL (pos); - if (INTVAL (width) == HOST_BITS_PER_WIDE_INT) - mask = ~(HOST_WIDE_INT) 0; - else - mask = ((HOST_WIDE_INT) 1 << INTVAL (width)) - 1; - val &= ~(mask << shift); - val |= (INTVAL (trial) & mask) << shift; - val = trunc_int_for_mode (val, GET_MODE (dest_reg)); - validate_unshare_change (insn, &SET_DEST (sets[i].rtl), - dest_reg, 1); - validate_unshare_change (insn, &SET_SRC (sets[i].rtl), - GEN_INT (val), 1); - if (apply_change_group ()) - { - rtx note = find_reg_note (insn, REG_EQUAL, NULL_RTX); - if (note) - { - remove_note (insn, note); - df_notes_rescan (insn); - } - src_eqv = NULL_RTX; - src_eqv_elt = NULL; - src_eqv_volatile = 0; - src_eqv_in_memory = 0; - src_eqv_hash = 0; - repeat = true; - break; - } - } - } - - /* We don't normally have an insn matching (set (pc) (pc)), so - check for this separately here. We will delete such an - insn below. - - For other cases such as a table jump or conditional jump - where we know the ultimate target, go ahead and replace the - operand. While that may not make a valid insn, we will - reemit the jump below (and also insert any necessary - barriers). */ - if (n_sets == 1 && dest == pc_rtx - && (trial == pc_rtx - || (GET_CODE (trial) == LABEL_REF - && ! condjump_p (insn)))) - { - /* Don't substitute non-local labels, this confuses CFG. */ - if (GET_CODE (trial) == LABEL_REF - && LABEL_REF_NONLOCAL_P (trial)) - continue; - - SET_SRC (sets[i].rtl) = trial; - cse_jumps_altered = true; - break; - } - - /* Reject certain invalid forms of CONST that we create. */ - else if (CONSTANT_P (trial) - && GET_CODE (trial) == CONST - /* Reject cases that will cause decode_rtx_const to - die. On the alpha when simplifying a switch, we - get (const (truncate (minus (label_ref) - (label_ref)))). */ - && (GET_CODE (XEXP (trial, 0)) == TRUNCATE - /* Likewise on IA-64, except without the - truncate. */ - || (GET_CODE (XEXP (trial, 0)) == MINUS - && GET_CODE (XEXP (XEXP (trial, 0), 0)) == LABEL_REF - && GET_CODE (XEXP (XEXP (trial, 0), 1)) == LABEL_REF))) - /* Do nothing for this case. */ - ; - - /* Look for a substitution that makes a valid insn. */ - else if (validate_unshare_change - (insn, &SET_SRC (sets[i].rtl), trial, 0)) - { - rtx new_rtx = canon_reg (SET_SRC (sets[i].rtl), insn); - - /* The result of apply_change_group can be ignored; see - canon_reg. */ - - validate_change (insn, &SET_SRC (sets[i].rtl), new_rtx, 1); - apply_change_group (); - - break; - } - - /* If we previously found constant pool entries for - constants and this is a constant, try making a - pool entry. Put it in src_folded unless we already have done - this since that is where it likely came from. */ - - else if (constant_pool_entries_cost - && CONSTANT_P (trial) - && (src_folded == 0 - || (!MEM_P (src_folded) - && ! src_folded_force_flag)) - && GET_MODE_CLASS (mode) != MODE_CC - && mode != VOIDmode) - { - src_folded_force_flag = 1; - src_folded = trial; - src_folded_cost = constant_pool_entries_cost; - src_folded_regcost = constant_pool_entries_regcost; - } - } - - /* If we changed the insn too much, handle this set from scratch. */ - if (repeat) - { - i--; - continue; - } - - src = SET_SRC (sets[i].rtl); - - /* In general, it is good to have a SET with SET_SRC == SET_DEST. - However, there is an important exception: If both are registers - that are not the head of their equivalence class, replace SET_SRC - with the head of the class. If we do not do this, we will have - both registers live over a portion of the basic block. This way, - their lifetimes will likely abut instead of overlapping. */ - if (REG_P (dest) - && REGNO_QTY_VALID_P (REGNO (dest))) - { - int dest_q = REG_QTY (REGNO (dest)); - struct qty_table_elem *dest_ent = &qty_table[dest_q]; - - if (dest_ent->mode == GET_MODE (dest) - && dest_ent->first_reg != REGNO (dest) - && REG_P (src) && REGNO (src) == REGNO (dest) - /* Don't do this if the original insn had a hard reg as - SET_SRC or SET_DEST. */ - && (!REG_P (sets[i].src) - || REGNO (sets[i].src) >= FIRST_PSEUDO_REGISTER) - && (!REG_P (dest) || REGNO (dest) >= FIRST_PSEUDO_REGISTER)) - /* We can't call canon_reg here because it won't do anything if - SRC is a hard register. */ - { - int src_q = REG_QTY (REGNO (src)); - struct qty_table_elem *src_ent = &qty_table[src_q]; - int first = src_ent->first_reg; - rtx new_src - = (first >= FIRST_PSEUDO_REGISTER - ? regno_reg_rtx[first] : gen_rtx_REG (GET_MODE (src), first)); - - /* We must use validate-change even for this, because this - might be a special no-op instruction, suitable only to - tag notes onto. */ - if (validate_change (insn, &SET_SRC (sets[i].rtl), new_src, 0)) - { - src = new_src; - /* If we had a constant that is cheaper than what we are now - setting SRC to, use that constant. We ignored it when we - thought we could make this into a no-op. */ - if (src_const && COST (src_const) < COST (src) - && validate_change (insn, &SET_SRC (sets[i].rtl), - src_const, 0)) - src = src_const; - } - } - } - - /* If we made a change, recompute SRC values. */ - if (src != sets[i].src) - { - do_not_record = 0; - hash_arg_in_memory = 0; - sets[i].src = src; - sets[i].src_hash = HASH (src, mode); - sets[i].src_volatile = do_not_record; - sets[i].src_in_memory = hash_arg_in_memory; - sets[i].src_elt = lookup (src, sets[i].src_hash, mode); - } - - /* If this is a single SET, we are setting a register, and we have an - equivalent constant, we want to add a REG_EQUAL note if the constant - is different from the source. We don't want to do it for a constant - pseudo since verifying that this pseudo hasn't been eliminated is a - pain; moreover such a note won't help anything. - - Avoid a REG_EQUAL note for (CONST (MINUS (LABEL_REF) (LABEL_REF))) - which can be created for a reference to a compile time computable - entry in a jump table. */ - if (n_sets == 1 - && REG_P (dest) - && src_const - && !REG_P (src_const) - && !(GET_CODE (src_const) == SUBREG - && REG_P (SUBREG_REG (src_const))) - && !(GET_CODE (src_const) == CONST - && GET_CODE (XEXP (src_const, 0)) == MINUS - && GET_CODE (XEXP (XEXP (src_const, 0), 0)) == LABEL_REF - && GET_CODE (XEXP (XEXP (src_const, 0), 1)) == LABEL_REF) - && !rtx_equal_p (src, src_const)) - { - /* Make sure that the rtx is not shared. */ - src_const = copy_rtx (src_const); - - /* Record the actual constant value in a REG_EQUAL note, - making a new one if one does not already exist. */ - set_unique_reg_note (insn, REG_EQUAL, src_const); - df_notes_rescan (insn); - } - - /* Now deal with the destination. */ - do_not_record = 0; - - /* Look within any ZERO_EXTRACT to the MEM or REG within it. */ - while (GET_CODE (dest) == SUBREG - || GET_CODE (dest) == ZERO_EXTRACT - || GET_CODE (dest) == STRICT_LOW_PART) - dest = XEXP (dest, 0); - - sets[i].inner_dest = dest; - - if (MEM_P (dest)) - { -#ifdef PUSH_ROUNDING - /* Stack pushes invalidate the stack pointer. */ - rtx addr = XEXP (dest, 0); - if (GET_RTX_CLASS (GET_CODE (addr)) == RTX_AUTOINC - && XEXP (addr, 0) == stack_pointer_rtx) - invalidate (stack_pointer_rtx, VOIDmode); -#endif - dest = fold_rtx (dest, insn); - } - - /* Compute the hash code of the destination now, - before the effects of this instruction are recorded, - since the register values used in the address computation - are those before this instruction. */ - sets[i].dest_hash = HASH (dest, mode); - - /* Don't enter a bit-field in the hash table - because the value in it after the store - may not equal what was stored, due to truncation. */ - - if (GET_CODE (SET_DEST (sets[i].rtl)) == ZERO_EXTRACT) - { - rtx width = XEXP (SET_DEST (sets[i].rtl), 1); - - if (src_const != 0 && CONST_INT_P (src_const) - && CONST_INT_P (width) - && INTVAL (width) < HOST_BITS_PER_WIDE_INT - && ! (INTVAL (src_const) - & ((HOST_WIDE_INT) (-1) << INTVAL (width)))) - /* Exception: if the value is constant, - and it won't be truncated, record it. */ - ; - else - { - /* This is chosen so that the destination will be invalidated - but no new value will be recorded. - We must invalidate because sometimes constant - values can be recorded for bitfields. */ - sets[i].src_elt = 0; - sets[i].src_volatile = 1; - src_eqv = 0; - src_eqv_elt = 0; - } - } - - /* If only one set in a JUMP_INSN and it is now a no-op, we can delete - the insn. */ - else if (n_sets == 1 && dest == pc_rtx && src == pc_rtx) - { - /* One less use of the label this insn used to jump to. */ - delete_insn_and_edges (insn); - cse_jumps_altered = true; - /* No more processing for this set. */ - sets[i].rtl = 0; - } - - /* If this SET is now setting PC to a label, we know it used to - be a conditional or computed branch. */ - else if (dest == pc_rtx && GET_CODE (src) == LABEL_REF - && !LABEL_REF_NONLOCAL_P (src)) - { - /* We reemit the jump in as many cases as possible just in - case the form of an unconditional jump is significantly - different than a computed jump or conditional jump. - - If this insn has multiple sets, then reemitting the - jump is nontrivial. So instead we just force rerecognition - and hope for the best. */ - if (n_sets == 1) - { - rtx new_rtx, note; - - new_rtx = emit_jump_insn_before (gen_jump (XEXP (src, 0)), insn); - JUMP_LABEL (new_rtx) = XEXP (src, 0); - LABEL_NUSES (XEXP (src, 0))++; - - /* Make sure to copy over REG_NON_LOCAL_GOTO. */ - note = find_reg_note (insn, REG_NON_LOCAL_GOTO, 0); - if (note) - { - XEXP (note, 1) = NULL_RTX; - REG_NOTES (new_rtx) = note; - } - - delete_insn_and_edges (insn); - insn = new_rtx; - } - else - INSN_CODE (insn) = -1; - - /* Do not bother deleting any unreachable code, let jump do it. */ - cse_jumps_altered = true; - sets[i].rtl = 0; - } - - /* If destination is volatile, invalidate it and then do no further - processing for this assignment. */ - - else if (do_not_record) - { - if (REG_P (dest) || GET_CODE (dest) == SUBREG) - invalidate (dest, VOIDmode); - else if (MEM_P (dest)) - invalidate (dest, VOIDmode); - else if (GET_CODE (dest) == STRICT_LOW_PART - || GET_CODE (dest) == ZERO_EXTRACT) - invalidate (XEXP (dest, 0), GET_MODE (dest)); - sets[i].rtl = 0; - } - - if (sets[i].rtl != 0 && dest != SET_DEST (sets[i].rtl)) - sets[i].dest_hash = HASH (SET_DEST (sets[i].rtl), mode); - -#ifdef HAVE_cc0 - /* If setting CC0, record what it was set to, or a constant, if it - is equivalent to a constant. If it is being set to a floating-point - value, make a COMPARE with the appropriate constant of 0. If we - don't do this, later code can interpret this as a test against - const0_rtx, which can cause problems if we try to put it into an - insn as a floating-point operand. */ - if (dest == cc0_rtx) - { - this_insn_cc0 = src_const && mode != VOIDmode ? src_const : src; - this_insn_cc0_mode = mode; - if (FLOAT_MODE_P (mode)) - this_insn_cc0 = gen_rtx_COMPARE (VOIDmode, this_insn_cc0, - CONST0_RTX (mode)); - } -#endif - } - - /* Now enter all non-volatile source expressions in the hash table - if they are not already present. - Record their equivalence classes in src_elt. - This way we can insert the corresponding destinations into - the same classes even if the actual sources are no longer in them - (having been invalidated). */ - - if (src_eqv && src_eqv_elt == 0 && sets[0].rtl != 0 && ! src_eqv_volatile - && ! rtx_equal_p (src_eqv, SET_DEST (sets[0].rtl))) - { - struct table_elt *elt; - struct table_elt *classp = sets[0].src_elt; - rtx dest = SET_DEST (sets[0].rtl); - enum machine_mode eqvmode = GET_MODE (dest); - - if (GET_CODE (dest) == STRICT_LOW_PART) - { - eqvmode = GET_MODE (SUBREG_REG (XEXP (dest, 0))); - classp = 0; - } - if (insert_regs (src_eqv, classp, 0)) - { - rehash_using_reg (src_eqv); - src_eqv_hash = HASH (src_eqv, eqvmode); - } - elt = insert (src_eqv, classp, src_eqv_hash, eqvmode); - elt->in_memory = src_eqv_in_memory; - src_eqv_elt = elt; - - /* Check to see if src_eqv_elt is the same as a set source which - does not yet have an elt, and if so set the elt of the set source - to src_eqv_elt. */ - for (i = 0; i < n_sets; i++) - if (sets[i].rtl && sets[i].src_elt == 0 - && rtx_equal_p (SET_SRC (sets[i].rtl), src_eqv)) - sets[i].src_elt = src_eqv_elt; - } - - for (i = 0; i < n_sets; i++) - if (sets[i].rtl && ! sets[i].src_volatile - && ! rtx_equal_p (SET_SRC (sets[i].rtl), SET_DEST (sets[i].rtl))) - { - if (GET_CODE (SET_DEST (sets[i].rtl)) == STRICT_LOW_PART) - { - /* REG_EQUAL in setting a STRICT_LOW_PART - gives an equivalent for the entire destination register, - not just for the subreg being stored in now. - This is a more interesting equivalence, so we arrange later - to treat the entire reg as the destination. */ - sets[i].src_elt = src_eqv_elt; - sets[i].src_hash = src_eqv_hash; - } - else - { - /* Insert source and constant equivalent into hash table, if not - already present. */ - struct table_elt *classp = src_eqv_elt; - rtx src = sets[i].src; - rtx dest = SET_DEST (sets[i].rtl); - enum machine_mode mode - = GET_MODE (src) == VOIDmode ? GET_MODE (dest) : GET_MODE (src); - - /* It's possible that we have a source value known to be - constant but don't have a REG_EQUAL note on the insn. - Lack of a note will mean src_eqv_elt will be NULL. This - can happen where we've generated a SUBREG to access a - CONST_INT that is already in a register in a wider mode. - Ensure that the source expression is put in the proper - constant class. */ - if (!classp) - classp = sets[i].src_const_elt; - - if (sets[i].src_elt == 0) - { - struct table_elt *elt; - - /* Note that these insert_regs calls cannot remove - any of the src_elt's, because they would have failed to - match if not still valid. */ - if (insert_regs (src, classp, 0)) - { - rehash_using_reg (src); - sets[i].src_hash = HASH (src, mode); - } - elt = insert (src, classp, sets[i].src_hash, mode); - elt->in_memory = sets[i].src_in_memory; - sets[i].src_elt = classp = elt; - } - if (sets[i].src_const && sets[i].src_const_elt == 0 - && src != sets[i].src_const - && ! rtx_equal_p (sets[i].src_const, src)) - sets[i].src_elt = insert (sets[i].src_const, classp, - sets[i].src_const_hash, mode); - } - } - else if (sets[i].src_elt == 0) - /* If we did not insert the source into the hash table (e.g., it was - volatile), note the equivalence class for the REG_EQUAL value, if any, - so that the destination goes into that class. */ - sets[i].src_elt = src_eqv_elt; - - /* Record destination addresses in the hash table. This allows us to - check if they are invalidated by other sets. */ - for (i = 0; i < n_sets; i++) - { - if (sets[i].rtl) - { - rtx x = sets[i].inner_dest; - struct table_elt *elt; - enum machine_mode mode; - unsigned hash; - - if (MEM_P (x)) - { - x = XEXP (x, 0); - mode = GET_MODE (x); - hash = HASH (x, mode); - elt = lookup (x, hash, mode); - if (!elt) - { - if (insert_regs (x, NULL, 0)) - { - rtx dest = SET_DEST (sets[i].rtl); - - rehash_using_reg (x); - hash = HASH (x, mode); - sets[i].dest_hash = HASH (dest, GET_MODE (dest)); - } - elt = insert (x, NULL, hash, mode); - } - - sets[i].dest_addr_elt = elt; - } - else - sets[i].dest_addr_elt = NULL; - } - } - - invalidate_from_clobbers (insn); - - /* Some registers are invalidated by subroutine calls. Memory is - invalidated by non-constant calls. */ - - if (CALL_P (insn)) - { - if (!(RTL_CONST_OR_PURE_CALL_P (insn))) - invalidate_memory (); - invalidate_for_call (); - } - - /* Now invalidate everything set by this instruction. - If a SUBREG or other funny destination is being set, - sets[i].rtl is still nonzero, so here we invalidate the reg - a part of which is being set. */ - - for (i = 0; i < n_sets; i++) - if (sets[i].rtl) - { - /* We can't use the inner dest, because the mode associated with - a ZERO_EXTRACT is significant. */ - rtx dest = SET_DEST (sets[i].rtl); - - /* Needed for registers to remove the register from its - previous quantity's chain. - Needed for memory if this is a nonvarying address, unless - we have just done an invalidate_memory that covers even those. */ - if (REG_P (dest) || GET_CODE (dest) == SUBREG) - invalidate (dest, VOIDmode); - else if (MEM_P (dest)) - invalidate (dest, VOIDmode); - else if (GET_CODE (dest) == STRICT_LOW_PART - || GET_CODE (dest) == ZERO_EXTRACT) - invalidate (XEXP (dest, 0), GET_MODE (dest)); - } - - /* A volatile ASM or an UNSPEC_VOLATILE invalidates everything. */ - if (NONJUMP_INSN_P (insn) - && volatile_insn_p (PATTERN (insn))) - flush_hash_table (); - - /* Don't cse over a call to setjmp; on some machines (eg VAX) - the regs restored by the longjmp come from a later time - than the setjmp. */ - if (CALL_P (insn) && find_reg_note (insn, REG_SETJMP, NULL)) - { - flush_hash_table (); - goto done; - } - - /* Make sure registers mentioned in destinations - are safe for use in an expression to be inserted. - This removes from the hash table - any invalid entry that refers to one of these registers. - - We don't care about the return value from mention_regs because - we are going to hash the SET_DEST values unconditionally. */ - - for (i = 0; i < n_sets; i++) - { - if (sets[i].rtl) - { - rtx x = SET_DEST (sets[i].rtl); - - if (!REG_P (x)) - mention_regs (x); - else - { - /* We used to rely on all references to a register becoming - inaccessible when a register changes to a new quantity, - since that changes the hash code. However, that is not - safe, since after HASH_SIZE new quantities we get a - hash 'collision' of a register with its own invalid - entries. And since SUBREGs have been changed not to - change their hash code with the hash code of the register, - it wouldn't work any longer at all. So we have to check - for any invalid references lying around now. - This code is similar to the REG case in mention_regs, - but it knows that reg_tick has been incremented, and - it leaves reg_in_table as -1 . */ - unsigned int regno = REGNO (x); - unsigned int endregno = END_REGNO (x); - unsigned int i; - - for (i = regno; i < endregno; i++) - { - if (REG_IN_TABLE (i) >= 0) - { - remove_invalid_refs (i); - REG_IN_TABLE (i) = -1; - } - } - } - } - } - - /* We may have just removed some of the src_elt's from the hash table. - So replace each one with the current head of the same class. - Also check if destination addresses have been removed. */ - - for (i = 0; i < n_sets; i++) - if (sets[i].rtl) - { - if (sets[i].dest_addr_elt - && sets[i].dest_addr_elt->first_same_value == 0) - { - /* The elt was removed, which means this destination is not - valid after this instruction. */ - sets[i].rtl = NULL_RTX; - } - else if (sets[i].src_elt && sets[i].src_elt->first_same_value == 0) - /* If elt was removed, find current head of same class, - or 0 if nothing remains of that class. */ - { - struct table_elt *elt = sets[i].src_elt; - - while (elt && elt->prev_same_value) - elt = elt->prev_same_value; - - while (elt && elt->first_same_value == 0) - elt = elt->next_same_value; - sets[i].src_elt = elt ? elt->first_same_value : 0; - } - } - - /* Now insert the destinations into their equivalence classes. */ - - for (i = 0; i < n_sets; i++) - if (sets[i].rtl) - { - rtx dest = SET_DEST (sets[i].rtl); - struct table_elt *elt; - - /* Don't record value if we are not supposed to risk allocating - floating-point values in registers that might be wider than - memory. */ - if ((flag_float_store - && MEM_P (dest) - && FLOAT_MODE_P (GET_MODE (dest))) - /* Don't record BLKmode values, because we don't know the - size of it, and can't be sure that other BLKmode values - have the same or smaller size. */ - || GET_MODE (dest) == BLKmode - /* If we didn't put a REG_EQUAL value or a source into the hash - table, there is no point is recording DEST. */ - || sets[i].src_elt == 0 - /* If DEST is a paradoxical SUBREG and SRC is a ZERO_EXTEND - or SIGN_EXTEND, don't record DEST since it can cause - some tracking to be wrong. - - ??? Think about this more later. */ - || (paradoxical_subreg_p (dest) - && (GET_CODE (sets[i].src) == SIGN_EXTEND - || GET_CODE (sets[i].src) == ZERO_EXTEND))) - continue; - - /* STRICT_LOW_PART isn't part of the value BEING set, - and neither is the SUBREG inside it. - Note that in this case SETS[I].SRC_ELT is really SRC_EQV_ELT. */ - if (GET_CODE (dest) == STRICT_LOW_PART) - dest = SUBREG_REG (XEXP (dest, 0)); - - if (REG_P (dest) || GET_CODE (dest) == SUBREG) - /* Registers must also be inserted into chains for quantities. */ - if (insert_regs (dest, sets[i].src_elt, 1)) - { - /* If `insert_regs' changes something, the hash code must be - recalculated. */ - rehash_using_reg (dest); - sets[i].dest_hash = HASH (dest, GET_MODE (dest)); - } - - elt = insert (dest, sets[i].src_elt, - sets[i].dest_hash, GET_MODE (dest)); - - /* If this is a constant, insert the constant anchors with the - equivalent register-offset expressions using register DEST. */ - if (targetm.const_anchor - && REG_P (dest) - && SCALAR_INT_MODE_P (GET_MODE (dest)) - && GET_CODE (sets[i].src_elt->exp) == CONST_INT) - insert_const_anchors (dest, sets[i].src_elt->exp, GET_MODE (dest)); - - elt->in_memory = (MEM_P (sets[i].inner_dest) - && !MEM_READONLY_P (sets[i].inner_dest)); - - /* If we have (set (subreg:m1 (reg:m2 foo) 0) (bar:m1)), M1 is no - narrower than M2, and both M1 and M2 are the same number of words, - we are also doing (set (reg:m2 foo) (subreg:m2 (bar:m1) 0)) so - make that equivalence as well. - - However, BAR may have equivalences for which gen_lowpart - will produce a simpler value than gen_lowpart applied to - BAR (e.g., if BAR was ZERO_EXTENDed from M2), so we will scan all - BAR's equivalences. If we don't get a simplified form, make - the SUBREG. It will not be used in an equivalence, but will - cause two similar assignments to be detected. - - Note the loop below will find SUBREG_REG (DEST) since we have - already entered SRC and DEST of the SET in the table. */ - - if (GET_CODE (dest) == SUBREG - && (((GET_MODE_SIZE (GET_MODE (SUBREG_REG (dest))) - 1) - / UNITS_PER_WORD) - == (GET_MODE_SIZE (GET_MODE (dest)) - 1) / UNITS_PER_WORD) - && (GET_MODE_SIZE (GET_MODE (dest)) - >= GET_MODE_SIZE (GET_MODE (SUBREG_REG (dest)))) - && sets[i].src_elt != 0) - { - enum machine_mode new_mode = GET_MODE (SUBREG_REG (dest)); - struct table_elt *elt, *classp = 0; - - for (elt = sets[i].src_elt->first_same_value; elt; - elt = elt->next_same_value) - { - rtx new_src = 0; - unsigned src_hash; - struct table_elt *src_elt; - int byte = 0; - - /* Ignore invalid entries. */ - if (!REG_P (elt->exp) - && ! exp_equiv_p (elt->exp, elt->exp, 1, false)) - continue; - - /* We may have already been playing subreg games. If the - mode is already correct for the destination, use it. */ - if (GET_MODE (elt->exp) == new_mode) - new_src = elt->exp; - else - { - /* Calculate big endian correction for the SUBREG_BYTE. - We have already checked that M1 (GET_MODE (dest)) - is not narrower than M2 (new_mode). */ - if (BYTES_BIG_ENDIAN) - byte = (GET_MODE_SIZE (GET_MODE (dest)) - - GET_MODE_SIZE (new_mode)); - - new_src = simplify_gen_subreg (new_mode, elt->exp, - GET_MODE (dest), byte); - } - - /* The call to simplify_gen_subreg fails if the value - is VOIDmode, yet we can't do any simplification, e.g. - for EXPR_LISTs denoting function call results. - It is invalid to construct a SUBREG with a VOIDmode - SUBREG_REG, hence a zero new_src means we can't do - this substitution. */ - if (! new_src) - continue; - - src_hash = HASH (new_src, new_mode); - src_elt = lookup (new_src, src_hash, new_mode); - - /* Put the new source in the hash table is if isn't - already. */ - if (src_elt == 0) - { - if (insert_regs (new_src, classp, 0)) - { - rehash_using_reg (new_src); - src_hash = HASH (new_src, new_mode); - } - src_elt = insert (new_src, classp, src_hash, new_mode); - src_elt->in_memory = elt->in_memory; - } - else if (classp && classp != src_elt->first_same_value) - /* Show that two things that we've seen before are - actually the same. */ - merge_equiv_classes (src_elt, classp); - - classp = src_elt->first_same_value; - /* Ignore invalid entries. */ - while (classp - && !REG_P (classp->exp) - && ! exp_equiv_p (classp->exp, classp->exp, 1, false)) - classp = classp->next_same_value; - } - } - } - - /* Special handling for (set REG0 REG1) where REG0 is the - "cheapest", cheaper than REG1. After cse, REG1 will probably not - be used in the sequel, so (if easily done) change this insn to - (set REG1 REG0) and replace REG1 with REG0 in the previous insn - that computed their value. Then REG1 will become a dead store - and won't cloud the situation for later optimizations. - - Do not make this change if REG1 is a hard register, because it will - then be used in the sequel and we may be changing a two-operand insn - into a three-operand insn. - - Also do not do this if we are operating on a copy of INSN. */ - - if (n_sets == 1 && sets[0].rtl) - try_back_substitute_reg (sets[0].rtl, insn); - -done:; -} - -/* Remove from the hash table all expressions that reference memory. */ - -static void -invalidate_memory (void) -{ - int i; - struct table_elt *p, *next; - - for (i = 0; i < HASH_SIZE; i++) - for (p = table[i]; p; p = next) - { - next = p->next_same_hash; - if (p->in_memory) - remove_from_table (p, i); - } -} - -/* Perform invalidation on the basis of everything about INSN, - except for invalidating the actual places that are SET in it. - This includes the places CLOBBERed, and anything that might - alias with something that is SET or CLOBBERed. */ - -static void -invalidate_from_clobbers (rtx insn) -{ - rtx x = PATTERN (insn); - - if (GET_CODE (x) == CLOBBER) - { - rtx ref = XEXP (x, 0); - if (ref) - { - if (REG_P (ref) || GET_CODE (ref) == SUBREG - || MEM_P (ref)) - invalidate (ref, VOIDmode); - else if (GET_CODE (ref) == STRICT_LOW_PART - || GET_CODE (ref) == ZERO_EXTRACT) - invalidate (XEXP (ref, 0), GET_MODE (ref)); - } - } - else if (GET_CODE (x) == PARALLEL) - { - int i; - for (i = XVECLEN (x, 0) - 1; i >= 0; i--) - { - rtx y = XVECEXP (x, 0, i); - if (GET_CODE (y) == CLOBBER) - { - rtx ref = XEXP (y, 0); - if (REG_P (ref) || GET_CODE (ref) == SUBREG - || MEM_P (ref)) - invalidate (ref, VOIDmode); - else if (GET_CODE (ref) == STRICT_LOW_PART - || GET_CODE (ref) == ZERO_EXTRACT) - invalidate (XEXP (ref, 0), GET_MODE (ref)); - } - } - } -} - -/* Perform invalidation on the basis of everything about INSN. - This includes the places CLOBBERed, and anything that might - alias with something that is SET or CLOBBERed. */ - -static void -invalidate_from_sets_and_clobbers (rtx insn) -{ - rtx tem; - rtx x = PATTERN (insn); - - if (CALL_P (insn)) - { - for (tem = CALL_INSN_FUNCTION_USAGE (insn); tem; tem = XEXP (tem, 1)) - if (GET_CODE (XEXP (tem, 0)) == CLOBBER) - invalidate (SET_DEST (XEXP (tem, 0)), VOIDmode); - } - - /* Ensure we invalidate the destination register of a CALL insn. - This is necessary for machines where this register is a fixed_reg, - because no other code would invalidate it. */ - if (GET_CODE (x) == SET && GET_CODE (SET_SRC (x)) == CALL) - invalidate (SET_DEST (x), VOIDmode); - - else if (GET_CODE (x) == PARALLEL) - { - int i; - - for (i = XVECLEN (x, 0) - 1; i >= 0; i--) - { - rtx y = XVECEXP (x, 0, i); - if (GET_CODE (y) == CLOBBER) - { - rtx clobbered = XEXP (y, 0); - - if (REG_P (clobbered) - || GET_CODE (clobbered) == SUBREG) - invalidate (clobbered, VOIDmode); - else if (GET_CODE (clobbered) == STRICT_LOW_PART - || GET_CODE (clobbered) == ZERO_EXTRACT) - invalidate (XEXP (clobbered, 0), GET_MODE (clobbered)); - } - else if (GET_CODE (y) == SET && GET_CODE (SET_SRC (y)) == CALL) - invalidate (SET_DEST (y), VOIDmode); - } - } -} - -/* Process X, part of the REG_NOTES of an insn. Look at any REG_EQUAL notes - and replace any registers in them with either an equivalent constant - or the canonical form of the register. If we are inside an address, - only do this if the address remains valid. - - OBJECT is 0 except when within a MEM in which case it is the MEM. - - Return the replacement for X. */ - -static rtx -cse_process_notes_1 (rtx x, rtx object, bool *changed) -{ - enum rtx_code code = GET_CODE (x); - const char *fmt = GET_RTX_FORMAT (code); - int i; - - switch (code) - { - case CONST: - case SYMBOL_REF: - case LABEL_REF: - CASE_CONST_ANY: - case PC: - case CC0: - case LO_SUM: - return x; - - case MEM: - validate_change (x, &XEXP (x, 0), - cse_process_notes (XEXP (x, 0), x, changed), 0); - return x; - - case EXPR_LIST: - case INSN_LIST: - if (REG_NOTE_KIND (x) == REG_EQUAL) - XEXP (x, 0) = cse_process_notes (XEXP (x, 0), NULL_RTX, changed); - if (XEXP (x, 1)) - XEXP (x, 1) = cse_process_notes (XEXP (x, 1), NULL_RTX, changed); - return x; - - case SIGN_EXTEND: - case ZERO_EXTEND: - case SUBREG: - { - rtx new_rtx = cse_process_notes (XEXP (x, 0), object, changed); - /* We don't substitute VOIDmode constants into these rtx, - since they would impede folding. */ - if (GET_MODE (new_rtx) != VOIDmode) - validate_change (object, &XEXP (x, 0), new_rtx, 0); - return x; - } - - case REG: - i = REG_QTY (REGNO (x)); - - /* Return a constant or a constant register. */ - if (REGNO_QTY_VALID_P (REGNO (x))) - { - struct qty_table_elem *ent = &qty_table[i]; - - if (ent->const_rtx != NULL_RTX - && (CONSTANT_P (ent->const_rtx) - || REG_P (ent->const_rtx))) - { - rtx new_rtx = gen_lowpart (GET_MODE (x), ent->const_rtx); - if (new_rtx) - return copy_rtx (new_rtx); - } - } - - /* Otherwise, canonicalize this register. */ - return canon_reg (x, NULL_RTX); - - default: - break; - } - - for (i = 0; i < GET_RTX_LENGTH (code); i++) - if (fmt[i] == 'e') - validate_change (object, &XEXP (x, i), - cse_process_notes (XEXP (x, i), object, changed), 0); - - return x; -} - -static rtx -cse_process_notes (rtx x, rtx object, bool *changed) -{ - rtx new_rtx = cse_process_notes_1 (x, object, changed); - if (new_rtx != x) - *changed = true; - return new_rtx; -} - - -/* Find a path in the CFG, starting with FIRST_BB to perform CSE on. - - DATA is a pointer to a struct cse_basic_block_data, that is used to - describe the path. - It is filled with a queue of basic blocks, starting with FIRST_BB - and following a trace through the CFG. - - If all paths starting at FIRST_BB have been followed, or no new path - starting at FIRST_BB can be constructed, this function returns FALSE. - Otherwise, DATA->path is filled and the function returns TRUE indicating - that a path to follow was found. - - If FOLLOW_JUMPS is false, the maximum path length is 1 and the only - block in the path will be FIRST_BB. */ - -static bool -cse_find_path (basic_block first_bb, struct cse_basic_block_data *data, - int follow_jumps) -{ - basic_block bb; - edge e; - int path_size; - - bitmap_set_bit (cse_visited_basic_blocks, first_bb->index); - - /* See if there is a previous path. */ - path_size = data->path_size; - - /* There is a previous path. Make sure it started with FIRST_BB. */ - if (path_size) - gcc_assert (data->path[0].bb == first_bb); - - /* There was only one basic block in the last path. Clear the path and - return, so that paths starting at another basic block can be tried. */ - if (path_size == 1) - { - path_size = 0; - goto done; - } - - /* If the path was empty from the beginning, construct a new path. */ - if (path_size == 0) - data->path[path_size++].bb = first_bb; - else - { - /* Otherwise, path_size must be equal to or greater than 2, because - a previous path exists that is at least two basic blocks long. - - Update the previous branch path, if any. If the last branch was - previously along the branch edge, take the fallthrough edge now. */ - while (path_size >= 2) - { - basic_block last_bb_in_path, previous_bb_in_path; - edge e; - - --path_size; - last_bb_in_path = data->path[path_size].bb; - previous_bb_in_path = data->path[path_size - 1].bb; - - /* If we previously followed a path along the branch edge, try - the fallthru edge now. */ - if (EDGE_COUNT (previous_bb_in_path->succs) == 2 - && any_condjump_p (BB_END (previous_bb_in_path)) - && (e = find_edge (previous_bb_in_path, last_bb_in_path)) - && e == BRANCH_EDGE (previous_bb_in_path)) - { - bb = FALLTHRU_EDGE (previous_bb_in_path)->dest; - if (bb != EXIT_BLOCK_PTR - && single_pred_p (bb) - /* We used to assert here that we would only see blocks - that we have not visited yet. But we may end up - visiting basic blocks twice if the CFG has changed - in this run of cse_main, because when the CFG changes - the topological sort of the CFG also changes. A basic - blocks that previously had more than two predecessors - may now have a single predecessor, and become part of - a path that starts at another basic block. - - We still want to visit each basic block only once, so - halt the path here if we have already visited BB. */ - && !bitmap_bit_p (cse_visited_basic_blocks, bb->index)) - { - bitmap_set_bit (cse_visited_basic_blocks, bb->index); - data->path[path_size++].bb = bb; - break; - } - } - - data->path[path_size].bb = NULL; - } - - /* If only one block remains in the path, bail. */ - if (path_size == 1) - { - path_size = 0; - goto done; - } - } - - /* Extend the path if possible. */ - if (follow_jumps) - { - bb = data->path[path_size - 1].bb; - while (bb && path_size < PARAM_VALUE (PARAM_MAX_CSE_PATH_LENGTH)) - { - if (single_succ_p (bb)) - e = single_succ_edge (bb); - else if (EDGE_COUNT (bb->succs) == 2 - && any_condjump_p (BB_END (bb))) - { - /* First try to follow the branch. If that doesn't lead - to a useful path, follow the fallthru edge. */ - e = BRANCH_EDGE (bb); - if (!single_pred_p (e->dest)) - e = FALLTHRU_EDGE (bb); - } - else - e = NULL; - - if (e - && !((e->flags & EDGE_ABNORMAL_CALL) && cfun->has_nonlocal_label) - && e->dest != EXIT_BLOCK_PTR - && single_pred_p (e->dest) - /* Avoid visiting basic blocks twice. The large comment - above explains why this can happen. */ - && !bitmap_bit_p (cse_visited_basic_blocks, e->dest->index)) - { - basic_block bb2 = e->dest; - bitmap_set_bit (cse_visited_basic_blocks, bb2->index); - data->path[path_size++].bb = bb2; - bb = bb2; - } - else - bb = NULL; - } - } - -done: - data->path_size = path_size; - return path_size != 0; -} - -/* Dump the path in DATA to file F. NSETS is the number of sets - in the path. */ - -static void -cse_dump_path (struct cse_basic_block_data *data, int nsets, FILE *f) -{ - int path_entry; - - fprintf (f, ";; Following path with %d sets: ", nsets); - for (path_entry = 0; path_entry < data->path_size; path_entry++) - fprintf (f, "%d ", (data->path[path_entry].bb)->index); - fputc ('\n', dump_file); - fflush (f); -} - - -/* Return true if BB has exception handling successor edges. */ - -static bool -have_eh_succ_edges (basic_block bb) -{ - edge e; - edge_iterator ei; - - FOR_EACH_EDGE (e, ei, bb->succs) - if (e->flags & EDGE_EH) - return true; - - return false; -} - - -/* Scan to the end of the path described by DATA. Return an estimate of - the total number of SETs of all insns in the path. */ - -static void -cse_prescan_path (struct cse_basic_block_data *data) -{ - int nsets = 0; - int path_size = data->path_size; - int path_entry; - - /* Scan to end of each basic block in the path. */ - for (path_entry = 0; path_entry < path_size; path_entry++) - { - basic_block bb; - rtx insn; - - bb = data->path[path_entry].bb; - - FOR_BB_INSNS (bb, insn) - { - if (!INSN_P (insn)) - continue; - - /* A PARALLEL can have lots of SETs in it, - especially if it is really an ASM_OPERANDS. */ - if (GET_CODE (PATTERN (insn)) == PARALLEL) - nsets += XVECLEN (PATTERN (insn), 0); - else - nsets += 1; - } - } - - data->nsets = nsets; -} - -/* Process a single extended basic block described by EBB_DATA. */ - -static void -cse_extended_basic_block (struct cse_basic_block_data *ebb_data) -{ - int path_size = ebb_data->path_size; - int path_entry; - int num_insns = 0; - - /* Allocate the space needed by qty_table. */ - qty_table = XNEWVEC (struct qty_table_elem, max_qty); - - new_basic_block (); - cse_ebb_live_in = df_get_live_in (ebb_data->path[0].bb); - cse_ebb_live_out = df_get_live_out (ebb_data->path[path_size - 1].bb); - for (path_entry = 0; path_entry < path_size; path_entry++) - { - basic_block bb; - rtx insn; - - bb = ebb_data->path[path_entry].bb; - - /* Invalidate recorded information for eh regs if there is an EH - edge pointing to that bb. */ - if (bb_has_eh_pred (bb)) - { - df_ref *def_rec; - - for (def_rec = df_get_artificial_defs (bb->index); *def_rec; def_rec++) - { - df_ref def = *def_rec; - if (DF_REF_FLAGS (def) & DF_REF_AT_TOP) - invalidate (DF_REF_REG (def), GET_MODE (DF_REF_REG (def))); - } - } - - optimize_this_for_speed_p = optimize_bb_for_speed_p (bb); - FOR_BB_INSNS (bb, insn) - { - /* If we have processed 1,000 insns, flush the hash table to - avoid extreme quadratic behavior. We must not include NOTEs - in the count since there may be more of them when generating - debugging information. If we clear the table at different - times, code generated with -g -O might be different than code - generated with -O but not -g. - - FIXME: This is a real kludge and needs to be done some other - way. */ - if (NONDEBUG_INSN_P (insn) - && num_insns++ > PARAM_VALUE (PARAM_MAX_CSE_INSNS)) - { - flush_hash_table (); - num_insns = 0; - } - - if (INSN_P (insn)) - { - /* Process notes first so we have all notes in canonical forms - when looking for duplicate operations. */ - if (REG_NOTES (insn)) - { - bool changed = false; - REG_NOTES (insn) = cse_process_notes (REG_NOTES (insn), - NULL_RTX, &changed); - if (changed) - df_notes_rescan (insn); - } - - cse_insn (insn); - - /* If we haven't already found an insn where we added a LABEL_REF, - check this one. */ - if (INSN_P (insn) && !recorded_label_ref - && for_each_rtx (&PATTERN (insn), check_for_label_ref, - (void *) insn)) - recorded_label_ref = true; - -#ifdef HAVE_cc0 - if (NONDEBUG_INSN_P (insn)) - { - /* If the previous insn sets CC0 and this insn no - longer references CC0, delete the previous insn. - Here we use fact that nothing expects CC0 to be - valid over an insn, which is true until the final - pass. */ - rtx prev_insn, tem; - - prev_insn = prev_nonnote_nondebug_insn (insn); - if (prev_insn && NONJUMP_INSN_P (prev_insn) - && (tem = single_set (prev_insn)) != NULL_RTX - && SET_DEST (tem) == cc0_rtx - && ! reg_mentioned_p (cc0_rtx, PATTERN (insn))) - delete_insn (prev_insn); - - /* If this insn is not the last insn in the basic - block, it will be PREV_INSN(insn) in the next - iteration. If we recorded any CC0-related - information for this insn, remember it. */ - if (insn != BB_END (bb)) - { - prev_insn_cc0 = this_insn_cc0; - prev_insn_cc0_mode = this_insn_cc0_mode; - } - } -#endif - } - } - - /* With non-call exceptions, we are not always able to update - the CFG properly inside cse_insn. So clean up possibly - redundant EH edges here. */ - if (cfun->can_throw_non_call_exceptions && have_eh_succ_edges (bb)) - cse_cfg_altered |= purge_dead_edges (bb); - - /* If we changed a conditional jump, we may have terminated - the path we are following. Check that by verifying that - the edge we would take still exists. If the edge does - not exist anymore, purge the remainder of the path. - Note that this will cause us to return to the caller. */ - if (path_entry < path_size - 1) - { - basic_block next_bb = ebb_data->path[path_entry + 1].bb; - if (!find_edge (bb, next_bb)) - { - do - { - path_size--; - - /* If we truncate the path, we must also reset the - visited bit on the remaining blocks in the path, - or we will never visit them at all. */ - bitmap_clear_bit (cse_visited_basic_blocks, - ebb_data->path[path_size].bb->index); - ebb_data->path[path_size].bb = NULL; - } - while (path_size - 1 != path_entry); - ebb_data->path_size = path_size; - } - } - - /* If this is a conditional jump insn, record any known - equivalences due to the condition being tested. */ - insn = BB_END (bb); - if (path_entry < path_size - 1 - && JUMP_P (insn) - && single_set (insn) - && any_condjump_p (insn)) - { - basic_block next_bb = ebb_data->path[path_entry + 1].bb; - bool taken = (next_bb == BRANCH_EDGE (bb)->dest); - record_jump_equiv (insn, taken); - } - -#ifdef HAVE_cc0 - /* Clear the CC0-tracking related insns, they can't provide - useful information across basic block boundaries. */ - prev_insn_cc0 = 0; -#endif - } - - gcc_assert (next_qty <= max_qty); - - free (qty_table); -} - - -/* Perform cse on the instructions of a function. - F is the first instruction. - NREGS is one plus the highest pseudo-reg number used in the instruction. - - Return 2 if jump optimizations should be redone due to simplifications - in conditional jump instructions. - Return 1 if the CFG should be cleaned up because it has been modified. - Return 0 otherwise. */ - -static int -cse_main (rtx f ATTRIBUTE_UNUSED, int nregs) -{ - struct cse_basic_block_data ebb_data; - basic_block bb; - int *rc_order = XNEWVEC (int, last_basic_block); - int i, n_blocks; - - df_set_flags (DF_LR_RUN_DCE); - df_note_add_problem (); - df_analyze (); - df_set_flags (DF_DEFER_INSN_RESCAN); - - reg_scan (get_insns (), max_reg_num ()); - init_cse_reg_info (nregs); - - ebb_data.path = XNEWVEC (struct branch_path, - PARAM_VALUE (PARAM_MAX_CSE_PATH_LENGTH)); - - cse_cfg_altered = false; - cse_jumps_altered = false; - recorded_label_ref = false; - constant_pool_entries_cost = 0; - constant_pool_entries_regcost = 0; - ebb_data.path_size = 0; - ebb_data.nsets = 0; - rtl_hooks = cse_rtl_hooks; - - init_recog (); - init_alias_analysis (); - - reg_eqv_table = XNEWVEC (struct reg_eqv_elem, nregs); - - /* Set up the table of already visited basic blocks. */ - cse_visited_basic_blocks = sbitmap_alloc (last_basic_block); - bitmap_clear (cse_visited_basic_blocks); - - /* Loop over basic blocks in reverse completion order (RPO), - excluding the ENTRY and EXIT blocks. */ - n_blocks = pre_and_rev_post_order_compute (NULL, rc_order, false); - i = 0; - while (i < n_blocks) - { - /* Find the first block in the RPO queue that we have not yet - processed before. */ - do - { - bb = BASIC_BLOCK (rc_order[i++]); - } - while (bitmap_bit_p (cse_visited_basic_blocks, bb->index) - && i < n_blocks); - - /* Find all paths starting with BB, and process them. */ - while (cse_find_path (bb, &ebb_data, flag_cse_follow_jumps)) - { - /* Pre-scan the path. */ - cse_prescan_path (&ebb_data); - - /* If this basic block has no sets, skip it. */ - if (ebb_data.nsets == 0) - continue; - - /* Get a reasonable estimate for the maximum number of qty's - needed for this path. For this, we take the number of sets - and multiply that by MAX_RECOG_OPERANDS. */ - max_qty = ebb_data.nsets * MAX_RECOG_OPERANDS; - - /* Dump the path we're about to process. */ - if (dump_file) - cse_dump_path (&ebb_data, ebb_data.nsets, dump_file); - - cse_extended_basic_block (&ebb_data); - } - } - - /* Clean up. */ - end_alias_analysis (); - free (reg_eqv_table); - free (ebb_data.path); - sbitmap_free (cse_visited_basic_blocks); - free (rc_order); - rtl_hooks = general_rtl_hooks; - - if (cse_jumps_altered || recorded_label_ref) - return 2; - else if (cse_cfg_altered) - return 1; - else - return 0; -} - -/* Called via for_each_rtx to see if an insn is using a LABEL_REF for - which there isn't a REG_LABEL_OPERAND note. - Return one if so. DATA is the insn. */ - -static int -check_for_label_ref (rtx *rtl, void *data) -{ - rtx insn = (rtx) data; - - /* If this insn uses a LABEL_REF and there isn't a REG_LABEL_OPERAND - note for it, we must rerun jump since it needs to place the note. If - this is a LABEL_REF for a CODE_LABEL that isn't in the insn chain, - don't do this since no REG_LABEL_OPERAND will be added. */ - return (GET_CODE (*rtl) == LABEL_REF - && ! LABEL_REF_NONLOCAL_P (*rtl) - && (!JUMP_P (insn) - || !label_is_jump_target_p (XEXP (*rtl, 0), insn)) - && LABEL_P (XEXP (*rtl, 0)) - && INSN_UID (XEXP (*rtl, 0)) != 0 - && ! find_reg_note (insn, REG_LABEL_OPERAND, XEXP (*rtl, 0))); -} - -/* Count the number of times registers are used (not set) in X. - COUNTS is an array in which we accumulate the count, INCR is how much - we count each register usage. - - Don't count a usage of DEST, which is the SET_DEST of a SET which - contains X in its SET_SRC. This is because such a SET does not - modify the liveness of DEST. - DEST is set to pc_rtx for a trapping insn, or for an insn with side effects. - We must then count uses of a SET_DEST regardless, because the insn can't be - deleted here. */ - -static void -count_reg_usage (rtx x, int *counts, rtx dest, int incr) -{ - enum rtx_code code; - rtx note; - const char *fmt; - int i, j; - - if (x == 0) - return; - - switch (code = GET_CODE (x)) - { - case REG: - if (x != dest) - counts[REGNO (x)] += incr; - return; - - case PC: - case CC0: - case CONST: - CASE_CONST_ANY: - case SYMBOL_REF: - case LABEL_REF: - return; - - case CLOBBER: - /* If we are clobbering a MEM, mark any registers inside the address - as being used. */ - if (MEM_P (XEXP (x, 0))) - count_reg_usage (XEXP (XEXP (x, 0), 0), counts, NULL_RTX, incr); - return; - - case SET: - /* Unless we are setting a REG, count everything in SET_DEST. */ - if (!REG_P (SET_DEST (x))) - count_reg_usage (SET_DEST (x), counts, NULL_RTX, incr); - count_reg_usage (SET_SRC (x), counts, - dest ? dest : SET_DEST (x), - incr); - return; - - case DEBUG_INSN: - return; - - case CALL_INSN: - case INSN: - case JUMP_INSN: - /* We expect dest to be NULL_RTX here. If the insn may throw, - or if it cannot be deleted due to side-effects, mark this fact - by setting DEST to pc_rtx. */ - if ((!cfun->can_delete_dead_exceptions && !insn_nothrow_p (x)) - || side_effects_p (PATTERN (x))) - dest = pc_rtx; - if (code == CALL_INSN) - count_reg_usage (CALL_INSN_FUNCTION_USAGE (x), counts, dest, incr); - count_reg_usage (PATTERN (x), counts, dest, incr); - - /* Things used in a REG_EQUAL note aren't dead since loop may try to - use them. */ - - note = find_reg_equal_equiv_note (x); - if (note) - { - rtx eqv = XEXP (note, 0); - - if (GET_CODE (eqv) == EXPR_LIST) - /* This REG_EQUAL note describes the result of a function call. - Process all the arguments. */ - do - { - count_reg_usage (XEXP (eqv, 0), counts, dest, incr); - eqv = XEXP (eqv, 1); - } - while (eqv && GET_CODE (eqv) == EXPR_LIST); - else - count_reg_usage (eqv, counts, dest, incr); - } - return; - - case EXPR_LIST: - if (REG_NOTE_KIND (x) == REG_EQUAL - || (REG_NOTE_KIND (x) != REG_NONNEG && GET_CODE (XEXP (x,0)) == USE) - /* FUNCTION_USAGE expression lists may include (CLOBBER (mem /u)), - involving registers in the address. */ - || GET_CODE (XEXP (x, 0)) == CLOBBER) - count_reg_usage (XEXP (x, 0), counts, NULL_RTX, incr); - - count_reg_usage (XEXP (x, 1), counts, NULL_RTX, incr); - return; - - case ASM_OPERANDS: - /* Iterate over just the inputs, not the constraints as well. */ - for (i = ASM_OPERANDS_INPUT_LENGTH (x) - 1; i >= 0; i--) - count_reg_usage (ASM_OPERANDS_INPUT (x, i), counts, dest, incr); - return; - - case INSN_LIST: - gcc_unreachable (); - - default: - break; - } - - fmt = GET_RTX_FORMAT (code); - for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) - { - if (fmt[i] == 'e') - count_reg_usage (XEXP (x, i), counts, dest, incr); - else if (fmt[i] == 'E') - for (j = XVECLEN (x, i) - 1; j >= 0; j--) - count_reg_usage (XVECEXP (x, i, j), counts, dest, incr); - } -} - -/* Return true if X is a dead register. */ - -static inline int -is_dead_reg (rtx x, int *counts) -{ - return (REG_P (x) - && REGNO (x) >= FIRST_PSEUDO_REGISTER - && counts[REGNO (x)] == 0); -} - -/* Return true if set is live. */ -static bool -set_live_p (rtx set, rtx insn ATTRIBUTE_UNUSED, /* Only used with HAVE_cc0. */ - int *counts) -{ -#ifdef HAVE_cc0 - rtx tem; -#endif - - if (set_noop_p (set)) - ; - -#ifdef HAVE_cc0 - else if (GET_CODE (SET_DEST (set)) == CC0 - && !side_effects_p (SET_SRC (set)) - && ((tem = next_nonnote_nondebug_insn (insn)) == NULL_RTX - || !INSN_P (tem) - || !reg_referenced_p (cc0_rtx, PATTERN (tem)))) - return false; -#endif - else if (!is_dead_reg (SET_DEST (set), counts) - || side_effects_p (SET_SRC (set))) - return true; - return false; -} - -/* Return true if insn is live. */ - -static bool -insn_live_p (rtx insn, int *counts) -{ - int i; - if (!cfun->can_delete_dead_exceptions && !insn_nothrow_p (insn)) - return true; - else if (GET_CODE (PATTERN (insn)) == SET) - return set_live_p (PATTERN (insn), insn, counts); - else if (GET_CODE (PATTERN (insn)) == PARALLEL) - { - for (i = XVECLEN (PATTERN (insn), 0) - 1; i >= 0; i--) - { - rtx elt = XVECEXP (PATTERN (insn), 0, i); - - if (GET_CODE (elt) == SET) - { - if (set_live_p (elt, insn, counts)) - return true; - } - else if (GET_CODE (elt) != CLOBBER && GET_CODE (elt) != USE) - return true; - } - return false; - } - else if (DEBUG_INSN_P (insn)) - { - rtx next; - - for (next = NEXT_INSN (insn); next; next = NEXT_INSN (next)) - if (NOTE_P (next)) - continue; - else if (!DEBUG_INSN_P (next)) - return true; - else if (INSN_VAR_LOCATION_DECL (insn) == INSN_VAR_LOCATION_DECL (next)) - return false; - - return true; - } - else - return true; -} - -/* Count the number of stores into pseudo. Callback for note_stores. */ - -static void -count_stores (rtx x, const_rtx set ATTRIBUTE_UNUSED, void *data) -{ - int *counts = (int *) data; - if (REG_P (x) && REGNO (x) >= FIRST_PSEUDO_REGISTER) - counts[REGNO (x)]++; -} - -struct dead_debug_insn_data -{ - int *counts; - rtx *replacements; - bool seen_repl; -}; - -/* Return if a DEBUG_INSN needs to be reset because some dead - pseudo doesn't have a replacement. Callback for for_each_rtx. */ - -static int -is_dead_debug_insn (rtx *loc, void *data) -{ - rtx x = *loc; - struct dead_debug_insn_data *ddid = (struct dead_debug_insn_data *) data; - - if (is_dead_reg (x, ddid->counts)) - { - if (ddid->replacements && ddid->replacements[REGNO (x)] != NULL_RTX) - ddid->seen_repl = true; - else - return 1; - } - return 0; -} - -/* Replace a dead pseudo in a DEBUG_INSN with replacement DEBUG_EXPR. - Callback for simplify_replace_fn_rtx. */ - -static rtx -replace_dead_reg (rtx x, const_rtx old_rtx ATTRIBUTE_UNUSED, void *data) -{ - rtx *replacements = (rtx *) data; - - if (REG_P (x) - && REGNO (x) >= FIRST_PSEUDO_REGISTER - && replacements[REGNO (x)] != NULL_RTX) - { - if (GET_MODE (x) == GET_MODE (replacements[REGNO (x)])) - return replacements[REGNO (x)]; - return lowpart_subreg (GET_MODE (x), replacements[REGNO (x)], - GET_MODE (replacements[REGNO (x)])); - } - return NULL_RTX; -} - -/* Scan all the insns and delete any that are dead; i.e., they store a register - that is never used or they copy a register to itself. - - This is used to remove insns made obviously dead by cse, loop or other - optimizations. It improves the heuristics in loop since it won't try to - move dead invariants out of loops or make givs for dead quantities. The - remaining passes of the compilation are also sped up. */ - -int -delete_trivially_dead_insns (rtx insns, int nreg) -{ - int *counts; - rtx insn, prev; - rtx *replacements = NULL; - int ndead = 0; - - timevar_push (TV_DELETE_TRIVIALLY_DEAD); - /* First count the number of times each register is used. */ - if (MAY_HAVE_DEBUG_INSNS) - { - counts = XCNEWVEC (int, nreg * 3); - for (insn = insns; insn; insn = NEXT_INSN (insn)) - if (DEBUG_INSN_P (insn)) - count_reg_usage (INSN_VAR_LOCATION_LOC (insn), counts + nreg, - NULL_RTX, 1); - else if (INSN_P (insn)) - { - count_reg_usage (insn, counts, NULL_RTX, 1); - note_stores (PATTERN (insn), count_stores, counts + nreg * 2); - } - /* If there can be debug insns, COUNTS are 3 consecutive arrays. - First one counts how many times each pseudo is used outside - of debug insns, second counts how many times each pseudo is - used in debug insns and third counts how many times a pseudo - is stored. */ - } - else - { - counts = XCNEWVEC (int, nreg); - for (insn = insns; insn; insn = NEXT_INSN (insn)) - if (INSN_P (insn)) - count_reg_usage (insn, counts, NULL_RTX, 1); - /* If no debug insns can be present, COUNTS is just an array - which counts how many times each pseudo is used. */ - } - /* Go from the last insn to the first and delete insns that only set unused - registers or copy a register to itself. As we delete an insn, remove - usage counts for registers it uses. - - The first jump optimization pass may leave a real insn as the last - insn in the function. We must not skip that insn or we may end - up deleting code that is not really dead. - - If some otherwise unused register is only used in DEBUG_INSNs, - try to create a DEBUG_EXPR temporary and emit a DEBUG_INSN before - the setter. Then go through DEBUG_INSNs and if a DEBUG_EXPR - has been created for the unused register, replace it with - the DEBUG_EXPR, otherwise reset the DEBUG_INSN. */ - for (insn = get_last_insn (); insn; insn = prev) - { - int live_insn = 0; - - prev = PREV_INSN (insn); - if (!INSN_P (insn)) - continue; - - live_insn = insn_live_p (insn, counts); - - /* If this is a dead insn, delete it and show registers in it aren't - being used. */ - - if (! live_insn && dbg_cnt (delete_trivial_dead)) - { - if (DEBUG_INSN_P (insn)) - count_reg_usage (INSN_VAR_LOCATION_LOC (insn), counts + nreg, - NULL_RTX, -1); - else - { - rtx set; - if (MAY_HAVE_DEBUG_INSNS - && (set = single_set (insn)) != NULL_RTX - && is_dead_reg (SET_DEST (set), counts) - /* Used at least once in some DEBUG_INSN. */ - && counts[REGNO (SET_DEST (set)) + nreg] > 0 - /* And set exactly once. */ - && counts[REGNO (SET_DEST (set)) + nreg * 2] == 1 - && !side_effects_p (SET_SRC (set)) - && asm_noperands (PATTERN (insn)) < 0) - { - rtx dval, bind; - - /* Create DEBUG_EXPR (and DEBUG_EXPR_DECL). */ - dval = make_debug_expr_from_rtl (SET_DEST (set)); - - /* Emit a debug bind insn before the insn in which - reg dies. */ - bind = gen_rtx_VAR_LOCATION (GET_MODE (SET_DEST (set)), - DEBUG_EXPR_TREE_DECL (dval), - SET_SRC (set), - VAR_INIT_STATUS_INITIALIZED); - count_reg_usage (bind, counts + nreg, NULL_RTX, 1); - - bind = emit_debug_insn_before (bind, insn); - df_insn_rescan (bind); - - if (replacements == NULL) - replacements = XCNEWVEC (rtx, nreg); - replacements[REGNO (SET_DEST (set))] = dval; - } - - count_reg_usage (insn, counts, NULL_RTX, -1); - ndead++; - } - delete_insn_and_edges (insn); - } - } - - if (MAY_HAVE_DEBUG_INSNS) - { - struct dead_debug_insn_data ddid; - ddid.counts = counts; - ddid.replacements = replacements; - for (insn = get_last_insn (); insn; insn = PREV_INSN (insn)) - if (DEBUG_INSN_P (insn)) - { - /* If this debug insn references a dead register that wasn't replaced - with an DEBUG_EXPR, reset the DEBUG_INSN. */ - ddid.seen_repl = false; - if (for_each_rtx (&INSN_VAR_LOCATION_LOC (insn), - is_dead_debug_insn, &ddid)) - { - INSN_VAR_LOCATION_LOC (insn) = gen_rtx_UNKNOWN_VAR_LOC (); - df_insn_rescan (insn); - } - else if (ddid.seen_repl) - { - INSN_VAR_LOCATION_LOC (insn) - = simplify_replace_fn_rtx (INSN_VAR_LOCATION_LOC (insn), - NULL_RTX, replace_dead_reg, - replacements); - df_insn_rescan (insn); - } - } - free (replacements); - } - - if (dump_file && ndead) - fprintf (dump_file, "Deleted %i trivially dead insns\n", - ndead); - /* Clean up. */ - free (counts); - timevar_pop (TV_DELETE_TRIVIALLY_DEAD); - return ndead; -} - -/* This function is called via for_each_rtx. The argument, NEWREG, is - a condition code register with the desired mode. If we are looking - at the same register in a different mode, replace it with - NEWREG. */ - -static int -cse_change_cc_mode (rtx *loc, void *data) -{ - struct change_cc_mode_args* args = (struct change_cc_mode_args*)data; - - if (*loc - && REG_P (*loc) - && REGNO (*loc) == REGNO (args->newreg) - && GET_MODE (*loc) != GET_MODE (args->newreg)) - { - validate_change (args->insn, loc, args->newreg, 1); - - return -1; - } - return 0; -} - -/* Change the mode of any reference to the register REGNO (NEWREG) to - GET_MODE (NEWREG) in INSN. */ - -static void -cse_change_cc_mode_insn (rtx insn, rtx newreg) -{ - struct change_cc_mode_args args; - int success; - - if (!INSN_P (insn)) - return; - - args.insn = insn; - args.newreg = newreg; - - for_each_rtx (&PATTERN (insn), cse_change_cc_mode, &args); - for_each_rtx (®_NOTES (insn), cse_change_cc_mode, &args); - - /* If the following assertion was triggered, there is most probably - something wrong with the cc_modes_compatible back end function. - CC modes only can be considered compatible if the insn - with the mode - replaced by any of the compatible modes - can still be recognized. */ - success = apply_change_group (); - gcc_assert (success); -} - -/* Change the mode of any reference to the register REGNO (NEWREG) to - GET_MODE (NEWREG), starting at START. Stop before END. Stop at - any instruction which modifies NEWREG. */ - -static void -cse_change_cc_mode_insns (rtx start, rtx end, rtx newreg) -{ - rtx insn; - - for (insn = start; insn != end; insn = NEXT_INSN (insn)) - { - if (! INSN_P (insn)) - continue; - - if (reg_set_p (newreg, insn)) - return; - - cse_change_cc_mode_insn (insn, newreg); - } -} - -/* BB is a basic block which finishes with CC_REG as a condition code - register which is set to CC_SRC. Look through the successors of BB - to find blocks which have a single predecessor (i.e., this one), - and look through those blocks for an assignment to CC_REG which is - equivalent to CC_SRC. CAN_CHANGE_MODE indicates whether we are - permitted to change the mode of CC_SRC to a compatible mode. This - returns VOIDmode if no equivalent assignments were found. - Otherwise it returns the mode which CC_SRC should wind up with. - ORIG_BB should be the same as BB in the outermost cse_cc_succs call, - but is passed unmodified down to recursive calls in order to prevent - endless recursion. - - The main complexity in this function is handling the mode issues. - We may have more than one duplicate which we can eliminate, and we - try to find a mode which will work for multiple duplicates. */ - -static enum machine_mode -cse_cc_succs (basic_block bb, basic_block orig_bb, rtx cc_reg, rtx cc_src, - bool can_change_mode) -{ - bool found_equiv; - enum machine_mode mode; - unsigned int insn_count; - edge e; - rtx insns[2]; - enum machine_mode modes[2]; - rtx last_insns[2]; - unsigned int i; - rtx newreg; - edge_iterator ei; - - /* We expect to have two successors. Look at both before picking - the final mode for the comparison. If we have more successors - (i.e., some sort of table jump, although that seems unlikely), - then we require all beyond the first two to use the same - mode. */ - - found_equiv = false; - mode = GET_MODE (cc_src); - insn_count = 0; - FOR_EACH_EDGE (e, ei, bb->succs) - { - rtx insn; - rtx end; - - if (e->flags & EDGE_COMPLEX) - continue; - - if (EDGE_COUNT (e->dest->preds) != 1 - || e->dest == EXIT_BLOCK_PTR - /* Avoid endless recursion on unreachable blocks. */ - || e->dest == orig_bb) - continue; - - end = NEXT_INSN (BB_END (e->dest)); - for (insn = BB_HEAD (e->dest); insn != end; insn = NEXT_INSN (insn)) - { - rtx set; - - if (! INSN_P (insn)) - continue; - - /* If CC_SRC is modified, we have to stop looking for - something which uses it. */ - if (modified_in_p (cc_src, insn)) - break; - - /* Check whether INSN sets CC_REG to CC_SRC. */ - set = single_set (insn); - if (set - && REG_P (SET_DEST (set)) - && REGNO (SET_DEST (set)) == REGNO (cc_reg)) - { - bool found; - enum machine_mode set_mode; - enum machine_mode comp_mode; - - found = false; - set_mode = GET_MODE (SET_SRC (set)); - comp_mode = set_mode; - if (rtx_equal_p (cc_src, SET_SRC (set))) - found = true; - else if (GET_CODE (cc_src) == COMPARE - && GET_CODE (SET_SRC (set)) == COMPARE - && mode != set_mode - && rtx_equal_p (XEXP (cc_src, 0), - XEXP (SET_SRC (set), 0)) - && rtx_equal_p (XEXP (cc_src, 1), - XEXP (SET_SRC (set), 1))) - - { - comp_mode = targetm.cc_modes_compatible (mode, set_mode); - if (comp_mode != VOIDmode - && (can_change_mode || comp_mode == mode)) - found = true; - } - - if (found) - { - found_equiv = true; - if (insn_count < ARRAY_SIZE (insns)) - { - insns[insn_count] = insn; - modes[insn_count] = set_mode; - last_insns[insn_count] = end; - ++insn_count; - - if (mode != comp_mode) - { - gcc_assert (can_change_mode); - mode = comp_mode; - - /* The modified insn will be re-recognized later. */ - PUT_MODE (cc_src, mode); - } - } - else - { - if (set_mode != mode) - { - /* We found a matching expression in the - wrong mode, but we don't have room to - store it in the array. Punt. This case - should be rare. */ - break; - } - /* INSN sets CC_REG to a value equal to CC_SRC - with the right mode. We can simply delete - it. */ - delete_insn (insn); - } - - /* We found an instruction to delete. Keep looking, - in the hopes of finding a three-way jump. */ - continue; - } - - /* We found an instruction which sets the condition - code, so don't look any farther. */ - break; - } - - /* If INSN sets CC_REG in some other way, don't look any - farther. */ - if (reg_set_p (cc_reg, insn)) - break; - } - - /* If we fell off the bottom of the block, we can keep looking - through successors. We pass CAN_CHANGE_MODE as false because - we aren't prepared to handle compatibility between the - further blocks and this block. */ - if (insn == end) - { - enum machine_mode submode; - - submode = cse_cc_succs (e->dest, orig_bb, cc_reg, cc_src, false); - if (submode != VOIDmode) - { - gcc_assert (submode == mode); - found_equiv = true; - can_change_mode = false; - } - } - } - - if (! found_equiv) - return VOIDmode; - - /* Now INSN_COUNT is the number of instructions we found which set - CC_REG to a value equivalent to CC_SRC. The instructions are in - INSNS. The modes used by those instructions are in MODES. */ - - newreg = NULL_RTX; - for (i = 0; i < insn_count; ++i) - { - if (modes[i] != mode) - { - /* We need to change the mode of CC_REG in INSNS[i] and - subsequent instructions. */ - if (! newreg) - { - if (GET_MODE (cc_reg) == mode) - newreg = cc_reg; - else - newreg = gen_rtx_REG (mode, REGNO (cc_reg)); - } - cse_change_cc_mode_insns (NEXT_INSN (insns[i]), last_insns[i], - newreg); - } - - delete_insn_and_edges (insns[i]); - } - - return mode; -} - -/* If we have a fixed condition code register (or two), walk through - the instructions and try to eliminate duplicate assignments. */ - -static void -cse_condition_code_reg (void) -{ - unsigned int cc_regno_1; - unsigned int cc_regno_2; - rtx cc_reg_1; - rtx cc_reg_2; - basic_block bb; - - if (! targetm.fixed_condition_code_regs (&cc_regno_1, &cc_regno_2)) - return; - - cc_reg_1 = gen_rtx_REG (CCmode, cc_regno_1); - if (cc_regno_2 != INVALID_REGNUM) - cc_reg_2 = gen_rtx_REG (CCmode, cc_regno_2); - else - cc_reg_2 = NULL_RTX; - - FOR_EACH_BB (bb) - { - rtx last_insn; - rtx cc_reg; - rtx insn; - rtx cc_src_insn; - rtx cc_src; - enum machine_mode mode; - enum machine_mode orig_mode; - - /* Look for blocks which end with a conditional jump based on a - condition code register. Then look for the instruction which - sets the condition code register. Then look through the - successor blocks for instructions which set the condition - code register to the same value. There are other possible - uses of the condition code register, but these are by far the - most common and the ones which we are most likely to be able - to optimize. */ - - last_insn = BB_END (bb); - if (!JUMP_P (last_insn)) - continue; - - if (reg_referenced_p (cc_reg_1, PATTERN (last_insn))) - cc_reg = cc_reg_1; - else if (cc_reg_2 && reg_referenced_p (cc_reg_2, PATTERN (last_insn))) - cc_reg = cc_reg_2; - else - continue; - - cc_src_insn = NULL_RTX; - cc_src = NULL_RTX; - for (insn = PREV_INSN (last_insn); - insn && insn != PREV_INSN (BB_HEAD (bb)); - insn = PREV_INSN (insn)) - { - rtx set; - - if (! INSN_P (insn)) - continue; - set = single_set (insn); - if (set - && REG_P (SET_DEST (set)) - && REGNO (SET_DEST (set)) == REGNO (cc_reg)) - { - cc_src_insn = insn; - cc_src = SET_SRC (set); - break; - } - else if (reg_set_p (cc_reg, insn)) - break; - } - - if (! cc_src_insn) - continue; - - if (modified_between_p (cc_src, cc_src_insn, NEXT_INSN (last_insn))) - continue; - - /* Now CC_REG is a condition code register used for a - conditional jump at the end of the block, and CC_SRC, in - CC_SRC_INSN, is the value to which that condition code - register is set, and CC_SRC is still meaningful at the end of - the basic block. */ - - orig_mode = GET_MODE (cc_src); - mode = cse_cc_succs (bb, bb, cc_reg, cc_src, true); - if (mode != VOIDmode) - { - gcc_assert (mode == GET_MODE (cc_src)); - if (mode != orig_mode) - { - rtx newreg = gen_rtx_REG (mode, REGNO (cc_reg)); - - cse_change_cc_mode_insn (cc_src_insn, newreg); - - /* Do the same in the following insns that use the - current value of CC_REG within BB. */ - cse_change_cc_mode_insns (NEXT_INSN (cc_src_insn), - NEXT_INSN (last_insn), - newreg); - } - } - } -} - - -/* Perform common subexpression elimination. Nonzero value from - `cse_main' means that jumps were simplified and some code may now - be unreachable, so do jump optimization again. */ -static bool -gate_handle_cse (void) -{ - return optimize > 0; -} - -static unsigned int -rest_of_handle_cse (void) -{ - int tem; - - if (dump_file) - dump_flow_info (dump_file, dump_flags); - - tem = cse_main (get_insns (), max_reg_num ()); - - /* If we are not running more CSE passes, then we are no longer - expecting CSE to be run. But always rerun it in a cheap mode. */ - cse_not_expected = !flag_rerun_cse_after_loop && !flag_gcse; - - if (tem == 2) - { - timevar_push (TV_JUMP); - rebuild_jump_labels (get_insns ()); - cleanup_cfg (CLEANUP_CFG_CHANGED); - timevar_pop (TV_JUMP); - } - else if (tem == 1 || optimize > 1) - cleanup_cfg (0); - - return 0; -} - -struct rtl_opt_pass pass_cse = -{ - { - RTL_PASS, - "cse1", /* name */ - OPTGROUP_NONE, /* optinfo_flags */ - gate_handle_cse, /* gate */ - rest_of_handle_cse, /* execute */ - NULL, /* sub */ - NULL, /* next */ - 0, /* static_pass_number */ - TV_CSE, /* tv_id */ - 0, /* properties_required */ - 0, /* properties_provided */ - 0, /* properties_destroyed */ - 0, /* todo_flags_start */ - TODO_df_finish | TODO_verify_rtl_sharing | - TODO_ggc_collect | - TODO_verify_flow, /* todo_flags_finish */ - } -}; - - -static bool -gate_handle_cse2 (void) -{ - return optimize > 0 && flag_rerun_cse_after_loop; -} - -/* Run second CSE pass after loop optimizations. */ -static unsigned int -rest_of_handle_cse2 (void) -{ - int tem; - - if (dump_file) - dump_flow_info (dump_file, dump_flags); - - tem = cse_main (get_insns (), max_reg_num ()); - - /* Run a pass to eliminate duplicated assignments to condition code - registers. We have to run this after bypass_jumps, because it - makes it harder for that pass to determine whether a jump can be - bypassed safely. */ - cse_condition_code_reg (); - - delete_trivially_dead_insns (get_insns (), max_reg_num ()); - - if (tem == 2) - { - timevar_push (TV_JUMP); - rebuild_jump_labels (get_insns ()); - cleanup_cfg (CLEANUP_CFG_CHANGED); - timevar_pop (TV_JUMP); - } - else if (tem == 1) - cleanup_cfg (0); - - cse_not_expected = 1; - return 0; -} - - -struct rtl_opt_pass pass_cse2 = -{ - { - RTL_PASS, - "cse2", /* name */ - OPTGROUP_NONE, /* optinfo_flags */ - gate_handle_cse2, /* gate */ - rest_of_handle_cse2, /* execute */ - NULL, /* sub */ - NULL, /* next */ - 0, /* static_pass_number */ - TV_CSE2, /* tv_id */ - 0, /* properties_required */ - 0, /* properties_provided */ - 0, /* properties_destroyed */ - 0, /* todo_flags_start */ - TODO_df_finish | TODO_verify_rtl_sharing | - TODO_ggc_collect | - TODO_verify_flow /* todo_flags_finish */ - } -}; - -static bool -gate_handle_cse_after_global_opts (void) -{ - return optimize > 0 && flag_rerun_cse_after_global_opts; -} - -/* Run second CSE pass after loop optimizations. */ -static unsigned int -rest_of_handle_cse_after_global_opts (void) -{ - int save_cfj; - int tem; - - /* We only want to do local CSE, so don't follow jumps. */ - save_cfj = flag_cse_follow_jumps; - flag_cse_follow_jumps = 0; - - rebuild_jump_labels (get_insns ()); - tem = cse_main (get_insns (), max_reg_num ()); - purge_all_dead_edges (); - delete_trivially_dead_insns (get_insns (), max_reg_num ()); - - cse_not_expected = !flag_rerun_cse_after_loop; - - /* If cse altered any jumps, rerun jump opts to clean things up. */ - if (tem == 2) - { - timevar_push (TV_JUMP); - rebuild_jump_labels (get_insns ()); - cleanup_cfg (CLEANUP_CFG_CHANGED); - timevar_pop (TV_JUMP); - } - else if (tem == 1) - cleanup_cfg (0); - - flag_cse_follow_jumps = save_cfj; - return 0; -} - -struct rtl_opt_pass pass_cse_after_global_opts = -{ - { - RTL_PASS, - "cse_local", /* name */ - OPTGROUP_NONE, /* optinfo_flags */ - gate_handle_cse_after_global_opts, /* gate */ - rest_of_handle_cse_after_global_opts, /* execute */ - NULL, /* sub */ - NULL, /* next */ - 0, /* static_pass_number */ - TV_CSE, /* tv_id */ - 0, /* properties_required */ - 0, /* properties_provided */ - 0, /* properties_destroyed */ - 0, /* todo_flags_start */ - TODO_df_finish | TODO_verify_rtl_sharing | - TODO_ggc_collect | - TODO_verify_flow /* todo_flags_finish */ - } -}; |