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authorBen Cheng <bccheng@google.com>2012-10-01 10:30:31 -0700
committerBen Cheng <bccheng@google.com>2012-10-01 10:30:31 -0700
commit82bcbebce43f0227f506d75a5b764b6847041bae (patch)
treefe9f8597b48a430c4daeb5123e3e8eb28e6f9da9 /gcc-4.7/gcc/regmove.c
parent3c052de3bb16ac53b6b6ed659ec7557eb84c7590 (diff)
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Initial check-in of gcc 4.7.2.
Change-Id: I4a2f5a921c21741a0e18bda986d77e5f1bef0365
Diffstat (limited to 'gcc-4.7/gcc/regmove.c')
-rw-r--r--gcc-4.7/gcc/regmove.c1386
1 files changed, 1386 insertions, 0 deletions
diff --git a/gcc-4.7/gcc/regmove.c b/gcc-4.7/gcc/regmove.c
new file mode 100644
index 000000000..454c97741
--- /dev/null
+++ b/gcc-4.7/gcc/regmove.c
@@ -0,0 +1,1386 @@
+/* Move registers around to reduce number of move instructions needed.
+ Copyright (C) 1987, 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
+ 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
+ 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/>. */
+
+
+/* This module makes some simple RTL code transformations which
+ improve the subsequent register allocation. */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "tm.h"
+#include "rtl.h"
+#include "tm_p.h"
+#include "insn-config.h"
+#include "recog.h"
+#include "target.h"
+#include "output.h"
+#include "regs.h"
+#include "hard-reg-set.h"
+#include "flags.h"
+#include "function.h"
+#include "expr.h"
+#include "basic-block.h"
+#include "except.h"
+#include "diagnostic-core.h"
+#include "reload.h"
+#include "timevar.h"
+#include "tree-pass.h"
+#include "df.h"
+#include "ira.h"
+
+static int optimize_reg_copy_1 (rtx, rtx, rtx);
+static void optimize_reg_copy_2 (rtx, rtx, rtx);
+static void optimize_reg_copy_3 (rtx, rtx, rtx);
+static void copy_src_to_dest (rtx, rtx, rtx);
+
+enum match_use
+{
+ READ,
+ WRITE,
+ READWRITE
+};
+
+struct match {
+ int with[MAX_RECOG_OPERANDS];
+ enum match_use use[MAX_RECOG_OPERANDS];
+ int commutative[MAX_RECOG_OPERANDS];
+ int early_clobber[MAX_RECOG_OPERANDS];
+};
+
+static int find_matches (rtx, struct match *);
+static int fixup_match_2 (rtx, rtx, rtx, rtx);
+
+/* Return nonzero if registers with CLASS1 and CLASS2 can be merged without
+ causing too much register allocation problems. */
+static int
+regclass_compatible_p (reg_class_t class0, reg_class_t class1)
+{
+ return (class0 == class1
+ || (reg_class_subset_p (class0, class1)
+ && ! targetm.class_likely_spilled_p (class0))
+ || (reg_class_subset_p (class1, class0)
+ && ! targetm.class_likely_spilled_p (class1)));
+}
+
+
+#ifdef AUTO_INC_DEC
+
+/* Find the place in the rtx X where REG is used as a memory address.
+ Return the MEM rtx that so uses it.
+ If PLUSCONST is nonzero, search instead for a memory address equivalent to
+ (plus REG (const_int PLUSCONST)).
+
+ If such an address does not appear, return 0.
+ If REG appears more than once, or is used other than in such an address,
+ return (rtx) 1. */
+
+static rtx
+find_use_as_address (rtx x, rtx reg, HOST_WIDE_INT plusconst)
+{
+ enum rtx_code code = GET_CODE (x);
+ const char * const fmt = GET_RTX_FORMAT (code);
+ int i;
+ rtx value = 0;
+ rtx tem;
+
+ if (code == MEM && XEXP (x, 0) == reg && plusconst == 0)
+ return x;
+
+ if (code == MEM && GET_CODE (XEXP (x, 0)) == PLUS
+ && XEXP (XEXP (x, 0), 0) == reg
+ && CONST_INT_P (XEXP (XEXP (x, 0), 1))
+ && INTVAL (XEXP (XEXP (x, 0), 1)) == plusconst)
+ return x;
+
+ if (code == SIGN_EXTRACT || code == ZERO_EXTRACT)
+ {
+ /* If REG occurs inside a MEM used in a bit-field reference,
+ that is unacceptable. */
+ if (find_use_as_address (XEXP (x, 0), reg, 0) != 0)
+ return (rtx) (size_t) 1;
+ }
+
+ if (x == reg)
+ return (rtx) (size_t) 1;
+
+ for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
+ {
+ if (fmt[i] == 'e')
+ {
+ tem = find_use_as_address (XEXP (x, i), reg, plusconst);
+ if (value == 0)
+ value = tem;
+ else if (tem != 0)
+ return (rtx) (size_t) 1;
+ }
+ else if (fmt[i] == 'E')
+ {
+ int j;
+ for (j = XVECLEN (x, i) - 1; j >= 0; j--)
+ {
+ tem = find_use_as_address (XVECEXP (x, i, j), reg, plusconst);
+ if (value == 0)
+ value = tem;
+ else if (tem != 0)
+ return (rtx) (size_t) 1;
+ }
+ }
+ }
+
+ return value;
+}
+
+
+/* INC_INSN is an instruction that adds INCREMENT to REG.
+ Try to fold INC_INSN as a post/pre in/decrement into INSN.
+ Iff INC_INSN_SET is nonzero, inc_insn has a destination different from src.
+ Return nonzero for success. */
+static int
+try_auto_increment (rtx insn, rtx inc_insn, rtx inc_insn_set, rtx reg,
+ HOST_WIDE_INT increment, int pre)
+{
+ enum rtx_code inc_code;
+
+ rtx pset = single_set (insn);
+ if (pset)
+ {
+ /* Can't use the size of SET_SRC, we might have something like
+ (sign_extend:SI (mem:QI ... */
+ rtx use = find_use_as_address (pset, reg, 0);
+ if (use != 0 && use != (rtx) (size_t) 1)
+ {
+ int size = GET_MODE_SIZE (GET_MODE (use));
+ if (0
+ || (HAVE_POST_INCREMENT
+ && pre == 0 && (inc_code = POST_INC, increment == size))
+ || (HAVE_PRE_INCREMENT
+ && pre == 1 && (inc_code = PRE_INC, increment == size))
+ || (HAVE_POST_DECREMENT
+ && pre == 0 && (inc_code = POST_DEC, increment == -size))
+ || (HAVE_PRE_DECREMENT
+ && pre == 1 && (inc_code = PRE_DEC, increment == -size))
+ )
+ {
+ if (inc_insn_set)
+ validate_change
+ (inc_insn,
+ &SET_SRC (inc_insn_set),
+ XEXP (SET_SRC (inc_insn_set), 0), 1);
+ validate_change (insn, &XEXP (use, 0),
+ gen_rtx_fmt_e (inc_code,
+ GET_MODE (XEXP (use, 0)), reg),
+ 1);
+ if (apply_change_group ())
+ {
+ /* If there is a REG_DEAD note on this insn, we must
+ change this not to REG_UNUSED meaning that the register
+ is set, but the value is dead. Failure to do so will
+ result in sched1 dying -- when it recomputes lifetime
+ information, the number of REG_DEAD notes will have
+ changed. */
+ rtx note = find_reg_note (insn, REG_DEAD, reg);
+ if (note)
+ PUT_REG_NOTE_KIND (note, REG_UNUSED);
+
+ add_reg_note (insn, REG_INC, reg);
+
+ if (! inc_insn_set)
+ delete_insn (inc_insn);
+ return 1;
+ }
+ }
+ }
+ }
+ return 0;
+}
+#endif
+
+
+static int *regno_src_regno;
+
+/* INSN is a copy from SRC to DEST, both registers, and SRC does not die
+ in INSN.
+
+ Search forward to see if SRC dies before either it or DEST is modified,
+ but don't scan past the end of a basic block. If so, we can replace SRC
+ with DEST and let SRC die in INSN.
+
+ This will reduce the number of registers live in that range and may enable
+ DEST to be tied to SRC, thus often saving one register in addition to a
+ register-register copy. */
+
+static int
+optimize_reg_copy_1 (rtx insn, rtx dest, rtx src)
+{
+ rtx p, q;
+ rtx note;
+ rtx dest_death = 0;
+ int sregno = REGNO (src);
+ int dregno = REGNO (dest);
+ basic_block bb = BLOCK_FOR_INSN (insn);
+
+ /* We don't want to mess with hard regs if register classes are small. */
+ if (sregno == dregno
+ || (targetm.small_register_classes_for_mode_p (GET_MODE (src))
+ && (sregno < FIRST_PSEUDO_REGISTER
+ || dregno < FIRST_PSEUDO_REGISTER))
+ /* We don't see all updates to SP if they are in an auto-inc memory
+ reference, so we must disallow this optimization on them. */
+ || sregno == STACK_POINTER_REGNUM || dregno == STACK_POINTER_REGNUM)
+ return 0;
+
+ for (p = NEXT_INSN (insn); p; p = NEXT_INSN (p))
+ {
+ if (! INSN_P (p))
+ continue;
+ if (BLOCK_FOR_INSN (p) != bb)
+ break;
+
+ if (reg_set_p (src, p) || reg_set_p (dest, p)
+ /* If SRC is an asm-declared register, it must not be replaced
+ in any asm. Unfortunately, the REG_EXPR tree for the asm
+ variable may be absent in the SRC rtx, so we can't check the
+ actual register declaration easily (the asm operand will have
+ it, though). To avoid complicating the test for a rare case,
+ we just don't perform register replacement for a hard reg
+ mentioned in an asm. */
+ || (sregno < FIRST_PSEUDO_REGISTER
+ && asm_noperands (PATTERN (p)) >= 0
+ && reg_overlap_mentioned_p (src, PATTERN (p)))
+ /* Don't change hard registers used by a call. */
+ || (CALL_P (p) && sregno < FIRST_PSEUDO_REGISTER
+ && find_reg_fusage (p, USE, src))
+ /* Don't change a USE of a register. */
+ || (GET_CODE (PATTERN (p)) == USE
+ && reg_overlap_mentioned_p (src, XEXP (PATTERN (p), 0))))
+ break;
+
+ /* See if all of SRC dies in P. This test is slightly more
+ conservative than it needs to be. */
+ if ((note = find_regno_note (p, REG_DEAD, sregno)) != 0
+ && GET_MODE (XEXP (note, 0)) == GET_MODE (src))
+ {
+ int failed = 0;
+ int d_length = 0;
+ int s_length = 0;
+ int d_n_calls = 0;
+ int s_n_calls = 0;
+ int s_freq_calls = 0;
+ int d_freq_calls = 0;
+
+ /* We can do the optimization. Scan forward from INSN again,
+ replacing regs as we go. Set FAILED if a replacement can't
+ be done. In that case, we can't move the death note for SRC.
+ This should be rare. */
+
+ /* Set to stop at next insn. */
+ for (q = next_real_insn (insn);
+ q != next_real_insn (p);
+ q = next_real_insn (q))
+ {
+ if (reg_overlap_mentioned_p (src, PATTERN (q)))
+ {
+ /* If SRC is a hard register, we might miss some
+ overlapping registers with validate_replace_rtx,
+ so we would have to undo it. We can't if DEST is
+ present in the insn, so fail in that combination
+ of cases. */
+ if (sregno < FIRST_PSEUDO_REGISTER
+ && reg_mentioned_p (dest, PATTERN (q)))
+ failed = 1;
+
+ /* Attempt to replace all uses. */
+ else if (!validate_replace_rtx (src, dest, q))
+ failed = 1;
+
+ /* If this succeeded, but some part of the register
+ is still present, undo the replacement. */
+ else if (sregno < FIRST_PSEUDO_REGISTER
+ && reg_overlap_mentioned_p (src, PATTERN (q)))
+ {
+ validate_replace_rtx (dest, src, q);
+ failed = 1;
+ }
+ }
+
+ /* For SREGNO, count the total number of insns scanned.
+ For DREGNO, count the total number of insns scanned after
+ passing the death note for DREGNO. */
+ if (!DEBUG_INSN_P (p))
+ {
+ s_length++;
+ if (dest_death)
+ d_length++;
+ }
+
+ /* If the insn in which SRC dies is a CALL_INSN, don't count it
+ as a call that has been crossed. Otherwise, count it. */
+ if (q != p && CALL_P (q))
+ {
+ /* Similarly, total calls for SREGNO, total calls beyond
+ the death note for DREGNO. */
+ s_n_calls++;
+ s_freq_calls += REG_FREQ_FROM_BB (BLOCK_FOR_INSN (q));
+ if (dest_death)
+ {
+ d_n_calls++;
+ d_freq_calls += REG_FREQ_FROM_BB (BLOCK_FOR_INSN (q));
+ }
+ }
+
+ /* If DEST dies here, remove the death note and save it for
+ later. Make sure ALL of DEST dies here; again, this is
+ overly conservative. */
+ if (dest_death == 0
+ && (dest_death = find_regno_note (q, REG_DEAD, dregno)) != 0)
+ {
+ if (GET_MODE (XEXP (dest_death, 0)) != GET_MODE (dest))
+ failed = 1, dest_death = 0;
+ else
+ remove_note (q, dest_death);
+ }
+ }
+
+ if (! failed)
+ {
+ /* These counters need to be updated if and only if we are
+ going to move the REG_DEAD note. */
+ if (sregno >= FIRST_PSEUDO_REGISTER)
+ {
+ if (REG_LIVE_LENGTH (sregno) >= 0)
+ {
+ REG_LIVE_LENGTH (sregno) -= s_length;
+ /* REG_LIVE_LENGTH is only an approximation after
+ combine if sched is not run, so make sure that we
+ still have a reasonable value. */
+ if (REG_LIVE_LENGTH (sregno) < 2)
+ REG_LIVE_LENGTH (sregno) = 2;
+ }
+
+ REG_N_CALLS_CROSSED (sregno) -= s_n_calls;
+ REG_FREQ_CALLS_CROSSED (sregno) -= s_freq_calls;
+ }
+
+ /* Move death note of SRC from P to INSN. */
+ remove_note (p, note);
+ XEXP (note, 1) = REG_NOTES (insn);
+ REG_NOTES (insn) = note;
+ }
+
+ /* DEST is also dead if INSN has a REG_UNUSED note for DEST. */
+ if (! dest_death
+ && (dest_death = find_regno_note (insn, REG_UNUSED, dregno)))
+ {
+ PUT_REG_NOTE_KIND (dest_death, REG_DEAD);
+ remove_note (insn, dest_death);
+ }
+
+ /* Put death note of DEST on P if we saw it die. */
+ if (dest_death)
+ {
+ XEXP (dest_death, 1) = REG_NOTES (p);
+ REG_NOTES (p) = dest_death;
+
+ if (dregno >= FIRST_PSEUDO_REGISTER)
+ {
+ /* If and only if we are moving the death note for DREGNO,
+ then we need to update its counters. */
+ if (REG_LIVE_LENGTH (dregno) >= 0)
+ REG_LIVE_LENGTH (dregno) += d_length;
+ REG_N_CALLS_CROSSED (dregno) += d_n_calls;
+ REG_FREQ_CALLS_CROSSED (dregno) += d_freq_calls;
+ }
+ }
+
+ return ! failed;
+ }
+
+ /* If SRC is a hard register which is set or killed in some other
+ way, we can't do this optimization. */
+ else if (sregno < FIRST_PSEUDO_REGISTER
+ && dead_or_set_p (p, src))
+ break;
+ }
+ return 0;
+}
+
+/* INSN is a copy of SRC to DEST, in which SRC dies. See if we now have
+ a sequence of insns that modify DEST followed by an insn that sets
+ SRC to DEST in which DEST dies, with no prior modification of DEST.
+ (There is no need to check if the insns in between actually modify
+ DEST. We should not have cases where DEST is not modified, but
+ the optimization is safe if no such modification is detected.)
+ In that case, we can replace all uses of DEST, starting with INSN and
+ ending with the set of SRC to DEST, with SRC. We do not do this
+ optimization if a CALL_INSN is crossed unless SRC already crosses a
+ call or if DEST dies before the copy back to SRC.
+
+ It is assumed that DEST and SRC are pseudos; it is too complicated to do
+ this for hard registers since the substitutions we may make might fail. */
+
+static void
+optimize_reg_copy_2 (rtx insn, rtx dest, rtx src)
+{
+ rtx p, q;
+ rtx set;
+ int sregno = REGNO (src);
+ int dregno = REGNO (dest);
+ basic_block bb = BLOCK_FOR_INSN (insn);
+
+ for (p = NEXT_INSN (insn); p; p = NEXT_INSN (p))
+ {
+ if (! INSN_P (p))
+ continue;
+ if (BLOCK_FOR_INSN (p) != bb)
+ break;
+
+ set = single_set (p);
+ if (set && SET_SRC (set) == dest && SET_DEST (set) == src
+ && find_reg_note (p, REG_DEAD, dest))
+ {
+ /* We can do the optimization. Scan forward from INSN again,
+ replacing regs as we go. */
+
+ /* Set to stop at next insn. */
+ for (q = insn; q != NEXT_INSN (p); q = NEXT_INSN (q))
+ if (INSN_P (q))
+ {
+ if (reg_mentioned_p (dest, PATTERN (q)))
+ {
+ rtx note;
+
+ PATTERN (q) = replace_rtx (PATTERN (q), dest, src);
+ note = FIND_REG_INC_NOTE (q, dest);
+ if (note)
+ {
+ remove_note (q, note);
+ add_reg_note (q, REG_INC, src);
+ }
+ df_insn_rescan (q);
+ }
+
+ if (CALL_P (q))
+ {
+ int freq = REG_FREQ_FROM_BB (BLOCK_FOR_INSN (q));
+ REG_N_CALLS_CROSSED (dregno)--;
+ REG_N_CALLS_CROSSED (sregno)++;
+ REG_FREQ_CALLS_CROSSED (dregno) -= freq;
+ REG_FREQ_CALLS_CROSSED (sregno) += freq;
+ }
+ }
+
+ remove_note (p, find_reg_note (p, REG_DEAD, dest));
+ REG_N_DEATHS (dregno)--;
+ remove_note (insn, find_reg_note (insn, REG_DEAD, src));
+ REG_N_DEATHS (sregno)--;
+ return;
+ }
+
+ if (reg_set_p (src, p)
+ || find_reg_note (p, REG_DEAD, dest)
+ || (CALL_P (p) && REG_N_CALLS_CROSSED (sregno) == 0))
+ break;
+ }
+}
+
+/* INSN is a ZERO_EXTEND or SIGN_EXTEND of SRC to DEST.
+ Look if SRC dies there, and if it is only set once, by loading
+ it from memory. If so, try to incorporate the zero/sign extension
+ into the memory read, change SRC to the mode of DEST, and alter
+ the remaining accesses to use the appropriate SUBREG. This allows
+ SRC and DEST to be tied later. */
+static void
+optimize_reg_copy_3 (rtx insn, rtx dest, rtx src)
+{
+ rtx src_reg = XEXP (src, 0);
+ int src_no = REGNO (src_reg);
+ int dst_no = REGNO (dest);
+ rtx p, set, set_insn;
+ enum machine_mode old_mode;
+ basic_block bb = BLOCK_FOR_INSN (insn);
+
+ if (src_no < FIRST_PSEUDO_REGISTER
+ || dst_no < FIRST_PSEUDO_REGISTER
+ || ! find_reg_note (insn, REG_DEAD, src_reg)
+ || REG_N_DEATHS (src_no) != 1
+ || REG_N_SETS (src_no) != 1)
+ return;
+
+ for (p = PREV_INSN (insn); p && ! reg_set_p (src_reg, p); p = PREV_INSN (p))
+ if (INSN_P (p) && BLOCK_FOR_INSN (p) != bb)
+ break;
+
+ if (! p || BLOCK_FOR_INSN (p) != bb)
+ return;
+
+ if (! (set = single_set (p))
+ || !MEM_P (SET_SRC (set))
+ /* If there's a REG_EQUIV note, this must be an insn that loads an
+ argument. Prefer keeping the note over doing this optimization. */
+ || find_reg_note (p, REG_EQUIV, NULL_RTX)
+ || SET_DEST (set) != src_reg)
+ return;
+
+ /* Be conservative: although this optimization is also valid for
+ volatile memory references, that could cause trouble in later passes. */
+ if (MEM_VOLATILE_P (SET_SRC (set)))
+ return;
+
+ /* Do not use a SUBREG to truncate from one mode to another if truncation
+ is not a nop. */
+ if (GET_MODE_BITSIZE (GET_MODE (src_reg)) <= GET_MODE_BITSIZE (GET_MODE (src))
+ && !TRULY_NOOP_TRUNCATION_MODES_P (GET_MODE (src), GET_MODE (src_reg)))
+ return;
+
+ set_insn = p;
+ old_mode = GET_MODE (src_reg);
+ PUT_MODE (src_reg, GET_MODE (src));
+ XEXP (src, 0) = SET_SRC (set);
+
+ /* Include this change in the group so that it's easily undone if
+ one of the changes in the group is invalid. */
+ validate_change (p, &SET_SRC (set), src, 1);
+
+ /* Now walk forward making additional replacements. We want to be able
+ to undo all the changes if a later substitution fails. */
+ while (p = NEXT_INSN (p), p != insn)
+ {
+ if (! INSN_P (p))
+ continue;
+
+ /* Make a tentative change. */
+ validate_replace_rtx_group (src_reg,
+ gen_lowpart_SUBREG (old_mode, src_reg),
+ p);
+ }
+
+ validate_replace_rtx_group (src, src_reg, insn);
+
+ /* Now see if all the changes are valid. */
+ if (! apply_change_group ())
+ {
+ /* One or more changes were no good. Back out everything. */
+ PUT_MODE (src_reg, old_mode);
+ XEXP (src, 0) = src_reg;
+ }
+ else
+ {
+ rtx note = find_reg_note (set_insn, REG_EQUAL, NULL_RTX);
+ if (note)
+ {
+ if (rtx_equal_p (XEXP (note, 0), XEXP (src, 0)))
+ {
+ XEXP (note, 0)
+ = gen_rtx_fmt_e (GET_CODE (src), GET_MODE (src),
+ XEXP (note, 0));
+ df_notes_rescan (set_insn);
+ }
+ else
+ remove_note (set_insn, note);
+ }
+ }
+}
+
+
+/* If we were not able to update the users of src to use dest directly, try
+ instead moving the value to dest directly before the operation. */
+
+static void
+copy_src_to_dest (rtx insn, rtx src, rtx dest)
+{
+ rtx seq;
+ rtx link;
+ rtx next;
+ rtx set;
+ rtx move_insn;
+ rtx *p_insn_notes;
+ rtx *p_move_notes;
+ int src_regno;
+ int dest_regno;
+
+ /* A REG_LIVE_LENGTH of -1 indicates the register is equivalent to a constant
+ or memory location and is used infrequently; a REG_LIVE_LENGTH of -2 is
+ parameter when there is no frame pointer that is not allocated a register.
+ For now, we just reject them, rather than incrementing the live length. */
+
+ if (REG_P (src)
+ && REG_LIVE_LENGTH (REGNO (src)) > 0
+ && REG_P (dest)
+ && REG_LIVE_LENGTH (REGNO (dest)) > 0
+ && (set = single_set (insn)) != NULL_RTX
+ && !reg_mentioned_p (dest, SET_SRC (set))
+ && GET_MODE (src) == GET_MODE (dest))
+ {
+ int old_num_regs = reg_rtx_no;
+
+ /* Generate the src->dest move. */
+ start_sequence ();
+ emit_move_insn (dest, src);
+ seq = get_insns ();
+ end_sequence ();
+ /* If this sequence uses new registers, we may not use it. */
+ if (old_num_regs != reg_rtx_no
+ || ! validate_replace_rtx (src, dest, insn))
+ {
+ /* We have to restore reg_rtx_no to its old value, lest
+ recompute_reg_usage will try to compute the usage of the
+ new regs, yet reg_n_info is not valid for them. */
+ reg_rtx_no = old_num_regs;
+ return;
+ }
+ emit_insn_before (seq, insn);
+ move_insn = PREV_INSN (insn);
+ p_move_notes = &REG_NOTES (move_insn);
+ p_insn_notes = &REG_NOTES (insn);
+
+ /* Move any notes mentioning src to the move instruction. */
+ for (link = REG_NOTES (insn); link != NULL_RTX; link = next)
+ {
+ next = XEXP (link, 1);
+ if (XEXP (link, 0) == src)
+ {
+ *p_move_notes = link;
+ p_move_notes = &XEXP (link, 1);
+ }
+ else
+ {
+ *p_insn_notes = link;
+ p_insn_notes = &XEXP (link, 1);
+ }
+ }
+
+ *p_move_notes = NULL_RTX;
+ *p_insn_notes = NULL_RTX;
+
+ /* Update the various register tables. */
+ dest_regno = REGNO (dest);
+ INC_REG_N_SETS (dest_regno, 1);
+ REG_LIVE_LENGTH (dest_regno)++;
+ src_regno = REGNO (src);
+ if (! find_reg_note (move_insn, REG_DEAD, src))
+ REG_LIVE_LENGTH (src_regno)++;
+ }
+}
+
+/* reg_set_in_bb[REGNO] points to basic block iff the register is set
+ only once in the given block and has REG_EQUAL note. */
+
+static basic_block *reg_set_in_bb;
+
+/* Size of reg_set_in_bb array. */
+static unsigned int max_reg_computed;
+
+
+/* Return whether REG is set in only one location, and is set to a
+ constant, but is set in a different basic block from INSN (an
+ instructions which uses REG). In this case REG is equivalent to a
+ constant, and we don't want to break that equivalence, because that
+ may increase register pressure and make reload harder. If REG is
+ set in the same basic block as INSN, we don't worry about it,
+ because we'll probably need a register anyhow (??? but what if REG
+ is used in a different basic block as well as this one?). */
+
+static bool
+reg_is_remote_constant_p (rtx reg, rtx insn)
+{
+ basic_block bb;
+ rtx p;
+ int max;
+
+ if (!reg_set_in_bb)
+ {
+ max_reg_computed = max = max_reg_num ();
+ reg_set_in_bb = XCNEWVEC (basic_block, max);
+
+ FOR_EACH_BB (bb)
+ FOR_BB_INSNS (bb, p)
+ {
+ rtx s;
+
+ if (!INSN_P (p))
+ continue;
+ s = single_set (p);
+ /* This is the instruction which sets REG. If there is a
+ REG_EQUAL note, then REG is equivalent to a constant. */
+ if (s != 0
+ && REG_P (SET_DEST (s))
+ && REG_N_SETS (REGNO (SET_DEST (s))) == 1
+ && find_reg_note (p, REG_EQUAL, NULL_RTX))
+ reg_set_in_bb[REGNO (SET_DEST (s))] = bb;
+ }
+ }
+
+ gcc_assert (REGNO (reg) < max_reg_computed);
+ if (reg_set_in_bb[REGNO (reg)] == NULL)
+ return false;
+ return (reg_set_in_bb[REGNO (reg)] != BLOCK_FOR_INSN (insn));
+}
+
+/* INSN is adding a CONST_INT to a REG. We search backwards looking for
+ another add immediate instruction with the same source and dest registers,
+ and if we find one, we change INSN to an increment, and return 1. If
+ no changes are made, we return 0.
+
+ This changes
+ (set (reg100) (plus reg1 offset1))
+ ...
+ (set (reg100) (plus reg1 offset2))
+ to
+ (set (reg100) (plus reg1 offset1))
+ ...
+ (set (reg100) (plus reg100 offset2-offset1)) */
+
+/* ??? What does this comment mean? */
+/* cse disrupts preincrement / postdecrement sequences when it finds a
+ hard register as ultimate source, like the frame pointer. */
+
+static int
+fixup_match_2 (rtx insn, rtx dst, rtx src, rtx offset)
+{
+ rtx p, dst_death = 0;
+ int length, num_calls = 0, freq_calls = 0;
+ basic_block bb = BLOCK_FOR_INSN (insn);
+
+ /* If SRC dies in INSN, we'd have to move the death note. This is
+ considered to be very unlikely, so we just skip the optimization
+ in this case. */
+ if (find_regno_note (insn, REG_DEAD, REGNO (src)))
+ return 0;
+
+ /* Scan backward to find the first instruction that sets DST. */
+
+ for (length = 0, p = PREV_INSN (insn); p; p = PREV_INSN (p))
+ {
+ rtx pset;
+
+ if (! INSN_P (p))
+ continue;
+ if (BLOCK_FOR_INSN (p) != bb)
+ break;
+
+ if (find_regno_note (p, REG_DEAD, REGNO (dst)))
+ dst_death = p;
+ if (! dst_death && !DEBUG_INSN_P (p))
+ length++;
+
+ pset = single_set (p);
+ if (pset && SET_DEST (pset) == dst
+ && GET_CODE (SET_SRC (pset)) == PLUS
+ && XEXP (SET_SRC (pset), 0) == src
+ && CONST_INT_P (XEXP (SET_SRC (pset), 1)))
+ {
+ HOST_WIDE_INT newconst
+ = INTVAL (offset) - INTVAL (XEXP (SET_SRC (pset), 1));
+ rtx add = gen_add3_insn (dst, dst, GEN_INT (newconst));
+
+ if (add && validate_change (insn, &PATTERN (insn), add, 0))
+ {
+ /* Remove the death note for DST from DST_DEATH. */
+ if (dst_death)
+ {
+ remove_death (REGNO (dst), dst_death);
+ REG_LIVE_LENGTH (REGNO (dst)) += length;
+ REG_N_CALLS_CROSSED (REGNO (dst)) += num_calls;
+ REG_FREQ_CALLS_CROSSED (REGNO (dst)) += freq_calls;
+ }
+
+ if (dump_file)
+ fprintf (dump_file,
+ "Fixed operand of insn %d.\n",
+ INSN_UID (insn));
+
+#ifdef AUTO_INC_DEC
+ for (p = PREV_INSN (insn); p; p = PREV_INSN (p))
+ {
+ if (! INSN_P (p))
+ continue;
+ if (BLOCK_FOR_INSN (p) != bb)
+ break;
+ if (reg_overlap_mentioned_p (dst, PATTERN (p)))
+ {
+ if (try_auto_increment (p, insn, 0, dst, newconst, 0))
+ return 1;
+ break;
+ }
+ }
+ for (p = NEXT_INSN (insn); p; p = NEXT_INSN (p))
+ {
+ if (! INSN_P (p))
+ continue;
+ if (BLOCK_FOR_INSN (p) != bb)
+ break;
+ if (reg_overlap_mentioned_p (dst, PATTERN (p)))
+ {
+ try_auto_increment (p, insn, 0, dst, newconst, 1);
+ break;
+ }
+ }
+#endif
+ return 1;
+ }
+ }
+
+ if (reg_set_p (dst, PATTERN (p)))
+ break;
+
+ /* If we have passed a call instruction, and the
+ pseudo-reg SRC is not already live across a call,
+ then don't perform the optimization. */
+ /* reg_set_p is overly conservative for CALL_INSNS, thinks that all
+ hard regs are clobbered. Thus, we only use it for src for
+ non-call insns. */
+ if (CALL_P (p))
+ {
+ if (! dst_death)
+ {
+ num_calls++;
+ freq_calls += REG_FREQ_FROM_BB (BLOCK_FOR_INSN (p));
+ }
+
+ if (REG_N_CALLS_CROSSED (REGNO (src)) == 0)
+ break;
+
+ if ((HARD_REGISTER_P (dst) && call_used_regs [REGNO (dst)])
+ || find_reg_fusage (p, CLOBBER, dst))
+ break;
+ }
+ else if (reg_set_p (src, PATTERN (p)))
+ break;
+ }
+
+ return 0;
+}
+
+/* A forward pass. Replace output operands with input operands. */
+
+static void
+regmove_forward_pass (void)
+{
+ basic_block bb;
+ rtx insn;
+
+ if (! flag_expensive_optimizations)
+ return;
+
+ if (dump_file)
+ fprintf (dump_file, "Starting forward pass...\n");
+
+ FOR_EACH_BB (bb)
+ {
+ FOR_BB_INSNS (bb, insn)
+ {
+ rtx set = single_set (insn);
+ if (! set)
+ continue;
+
+ if ((GET_CODE (SET_SRC (set)) == SIGN_EXTEND
+ || GET_CODE (SET_SRC (set)) == ZERO_EXTEND)
+ && REG_P (XEXP (SET_SRC (set), 0))
+ && REG_P (SET_DEST (set)))
+ optimize_reg_copy_3 (insn, SET_DEST (set), SET_SRC (set));
+
+ if (REG_P (SET_SRC (set))
+ && REG_P (SET_DEST (set)))
+ {
+ /* If this is a register-register copy where SRC is not dead,
+ see if we can optimize it. If this optimization succeeds,
+ it will become a copy where SRC is dead. */
+ if ((find_reg_note (insn, REG_DEAD, SET_SRC (set))
+ || optimize_reg_copy_1 (insn, SET_DEST (set), SET_SRC (set)))
+ && REGNO (SET_DEST (set)) >= FIRST_PSEUDO_REGISTER)
+ {
+ /* Similarly for a pseudo-pseudo copy when SRC is dead. */
+ if (REGNO (SET_SRC (set)) >= FIRST_PSEUDO_REGISTER)
+ optimize_reg_copy_2 (insn, SET_DEST (set), SET_SRC (set));
+ if (regno_src_regno[REGNO (SET_DEST (set))] < 0
+ && SET_SRC (set) != SET_DEST (set))
+ {
+ int srcregno = REGNO (SET_SRC (set));
+ if (regno_src_regno[srcregno] >= 0)
+ srcregno = regno_src_regno[srcregno];
+ regno_src_regno[REGNO (SET_DEST (set))] = srcregno;
+ }
+ }
+ }
+ }
+ }
+}
+
+/* A backward pass. Replace input operands with output operands. */
+
+static void
+regmove_backward_pass (void)
+{
+ basic_block bb;
+ rtx insn, prev;
+
+ if (dump_file)
+ fprintf (dump_file, "Starting backward pass...\n");
+
+ FOR_EACH_BB_REVERSE (bb)
+ {
+ /* ??? Use the safe iterator because fixup_match_2 can remove
+ insns via try_auto_increment. */
+ FOR_BB_INSNS_REVERSE_SAFE (bb, insn, prev)
+ {
+ struct match match;
+ rtx copy_src, copy_dst;
+ int op_no, match_no;
+ int success = 0;
+
+ if (! INSN_P (insn))
+ continue;
+
+ if (! find_matches (insn, &match))
+ continue;
+
+ /* Now scan through the operands looking for a destination operand
+ which is supposed to match a source operand.
+ Then scan backward for an instruction which sets the source
+ operand. If safe, then replace the source operand with the
+ dest operand in both instructions. */
+
+ copy_src = NULL_RTX;
+ copy_dst = NULL_RTX;
+ for (op_no = 0; op_no < recog_data.n_operands; op_no++)
+ {
+ rtx set, p, src, dst;
+ rtx src_note, dst_note;
+ int num_calls = 0, freq_calls = 0;
+ enum reg_class src_class, dst_class;
+ int length;
+
+ match_no = match.with[op_no];
+
+ /* Nothing to do if the two operands aren't supposed to match. */
+ if (match_no < 0)
+ continue;
+
+ dst = recog_data.operand[match_no];
+ src = recog_data.operand[op_no];
+
+ if (!REG_P (src))
+ continue;
+
+ if (!REG_P (dst)
+ || REGNO (dst) < FIRST_PSEUDO_REGISTER
+ || REG_LIVE_LENGTH (REGNO (dst)) < 0
+ || GET_MODE (src) != GET_MODE (dst))
+ continue;
+
+ /* If the operands already match, then there is nothing to do. */
+ if (operands_match_p (src, dst))
+ continue;
+
+ if (match.commutative[op_no] >= 0)
+ {
+ rtx comm = recog_data.operand[match.commutative[op_no]];
+ if (operands_match_p (comm, dst))
+ continue;
+ }
+
+ set = single_set (insn);
+ if (! set)
+ continue;
+
+ /* Note that single_set ignores parts of a parallel set for
+ which one of the destinations is REG_UNUSED. We can't
+ handle that here, since we can wind up rewriting things
+ such that a single register is set twice within a single
+ parallel. */
+ if (reg_set_p (src, insn))
+ continue;
+
+ /* match_no/dst must be a write-only operand, and
+ operand_operand/src must be a read-only operand. */
+ if (match.use[op_no] != READ
+ || match.use[match_no] != WRITE)
+ continue;
+
+ if (match.early_clobber[match_no]
+ && count_occurrences (PATTERN (insn), src, 0) > 1)
+ continue;
+
+ /* Make sure match_no is the destination. */
+ if (recog_data.operand[match_no] != SET_DEST (set))
+ continue;
+
+ if (REGNO (src) < FIRST_PSEUDO_REGISTER)
+ {
+ if (GET_CODE (SET_SRC (set)) == PLUS
+ && CONST_INT_P (XEXP (SET_SRC (set), 1))
+ && XEXP (SET_SRC (set), 0) == src
+ && fixup_match_2 (insn, dst, src,
+ XEXP (SET_SRC (set), 1)))
+ break;
+ continue;
+ }
+ src_class = reg_preferred_class (REGNO (src));
+ dst_class = reg_preferred_class (REGNO (dst));
+
+ if (! (src_note = find_reg_note (insn, REG_DEAD, src)))
+ {
+ /* We used to force the copy here like in other cases, but
+ it produces worse code, as it eliminates no copy
+ instructions and the copy emitted will be produced by
+ reload anyway. On patterns with multiple alternatives,
+ there may be better solution available.
+
+ In particular this change produced slower code for numeric
+ i387 programs. */
+
+ continue;
+ }
+
+ if (! regclass_compatible_p (src_class, dst_class))
+ {
+ if (!copy_src)
+ {
+ copy_src = src;
+ copy_dst = dst;
+ }
+ continue;
+ }
+
+ /* Can not modify an earlier insn to set dst if this insn
+ uses an old value in the source. */
+ if (reg_overlap_mentioned_p (dst, SET_SRC (set)))
+ {
+ if (!copy_src)
+ {
+ copy_src = src;
+ copy_dst = dst;
+ }
+ continue;
+ }
+
+ /* If src is set once in a different basic block,
+ and is set equal to a constant, then do not use
+ it for this optimization, as this would make it
+ no longer equivalent to a constant. */
+
+ if (reg_is_remote_constant_p (src, insn))
+ {
+ if (!copy_src)
+ {
+ copy_src = src;
+ copy_dst = dst;
+ }
+ continue;
+ }
+
+
+ if (dump_file)
+ fprintf (dump_file,
+ "Could fix operand %d of insn %d matching operand %d.\n",
+ op_no, INSN_UID (insn), match_no);
+
+ /* Scan backward to find the first instruction that uses
+ the input operand. If the operand is set here, then
+ replace it in both instructions with match_no. */
+
+ for (length = 0, p = PREV_INSN (insn); p; p = PREV_INSN (p))
+ {
+ rtx pset;
+
+ if (! INSN_P (p))
+ continue;
+ if (BLOCK_FOR_INSN (p) != bb)
+ break;
+
+ if (!DEBUG_INSN_P (p))
+ length++;
+
+ /* ??? See if all of SRC is set in P. This test is much
+ more conservative than it needs to be. */
+ pset = single_set (p);
+ if (pset && SET_DEST (pset) == src)
+ {
+ /* We use validate_replace_rtx, in case there
+ are multiple identical source operands. All
+ of them have to be changed at the same time:
+ when validate_replace_rtx() calls
+ apply_change_group(). */
+ validate_change (p, &SET_DEST (pset), dst, 1);
+ if (validate_replace_rtx (src, dst, insn))
+ success = 1;
+ break;
+ }
+
+ /* We can't make this change if DST is mentioned at
+ all in P, since we are going to change its value.
+ We can't make this change if SRC is read or
+ partially written in P, since we are going to
+ eliminate SRC. However, if it's a debug insn, we
+ can't refrain from making the change, for this
+ would cause codegen differences, so instead we
+ invalidate debug expressions that reference DST,
+ and adjust references to SRC in them so that they
+ become references to DST. */
+ if (reg_mentioned_p (dst, PATTERN (p)))
+ {
+ if (DEBUG_INSN_P (p))
+ validate_change (p, &INSN_VAR_LOCATION_LOC (p),
+ gen_rtx_UNKNOWN_VAR_LOC (), 1);
+ else
+ break;
+ }
+ if (reg_overlap_mentioned_p (src, PATTERN (p)))
+ {
+ if (DEBUG_INSN_P (p))
+ validate_replace_rtx_group (src, dst, p);
+ else
+ break;
+ }
+
+ /* If we have passed a call instruction, and the
+ pseudo-reg DST is not already live across a call,
+ then don't perform the optimization. */
+ if (CALL_P (p))
+ {
+ num_calls++;
+ freq_calls += REG_FREQ_FROM_BB (BLOCK_FOR_INSN (p));
+
+ if (REG_N_CALLS_CROSSED (REGNO (dst)) == 0)
+ break;
+ }
+ }
+
+ if (success)
+ {
+ int dstno, srcno;
+
+ /* Remove the death note for SRC from INSN. */
+ remove_note (insn, src_note);
+ /* Move the death note for SRC to P if it is used
+ there. */
+ if (reg_overlap_mentioned_p (src, PATTERN (p)))
+ {
+ XEXP (src_note, 1) = REG_NOTES (p);
+ REG_NOTES (p) = src_note;
+ }
+ /* If there is a REG_DEAD note for DST on P, then remove
+ it, because DST is now set there. */
+ if ((dst_note = find_reg_note (p, REG_DEAD, dst)))
+ remove_note (p, dst_note);
+
+ dstno = REGNO (dst);
+ srcno = REGNO (src);
+
+ INC_REG_N_SETS (dstno, 1);
+ INC_REG_N_SETS (srcno, -1);
+
+ REG_N_CALLS_CROSSED (dstno) += num_calls;
+ REG_N_CALLS_CROSSED (srcno) -= num_calls;
+ REG_FREQ_CALLS_CROSSED (dstno) += freq_calls;
+ REG_FREQ_CALLS_CROSSED (srcno) -= freq_calls;
+
+ REG_LIVE_LENGTH (dstno) += length;
+ if (REG_LIVE_LENGTH (srcno) >= 0)
+ {
+ REG_LIVE_LENGTH (srcno) -= length;
+ /* REG_LIVE_LENGTH is only an approximation after
+ combine if sched is not run, so make sure that we
+ still have a reasonable value. */
+ if (REG_LIVE_LENGTH (srcno) < 2)
+ REG_LIVE_LENGTH (srcno) = 2;
+ }
+
+ if (dump_file)
+ fprintf (dump_file,
+ "Fixed operand %d of insn %d matching operand %d.\n",
+ op_no, INSN_UID (insn), match_no);
+
+ break;
+ }
+ else if (num_changes_pending () > 0)
+ cancel_changes (0);
+ }
+
+ /* If we weren't able to replace any of the alternatives, try an
+ alternative approach of copying the source to the destination. */
+ if (!success && copy_src != NULL_RTX)
+ copy_src_to_dest (insn, copy_src, copy_dst);
+ }
+ }
+}
+
+/* Main entry for the register move optimization. */
+
+static unsigned int
+regmove_optimize (void)
+{
+ int i;
+ int nregs = max_reg_num ();
+
+ df_note_add_problem ();
+ df_analyze ();
+
+ regstat_init_n_sets_and_refs ();
+ regstat_compute_ri ();
+
+ if (flag_ira_loop_pressure)
+ ira_set_pseudo_classes (dump_file);
+
+ regno_src_regno = XNEWVEC (int, nregs);
+ for (i = nregs; --i >= 0; )
+ regno_src_regno[i] = -1;
+
+ /* A forward pass. Replace output operands with input operands. */
+ regmove_forward_pass ();
+
+ /* A backward pass. Replace input operands with output operands. */
+ regmove_backward_pass ();
+
+ /* Clean up. */
+ free (regno_src_regno);
+ if (reg_set_in_bb)
+ {
+ free (reg_set_in_bb);
+ reg_set_in_bb = NULL;
+ }
+ regstat_free_n_sets_and_refs ();
+ regstat_free_ri ();
+ if (flag_ira_loop_pressure)
+ free_reg_info ();
+ return 0;
+}
+
+/* Returns nonzero if INSN's pattern has matching constraints for any operand.
+ Returns 0 if INSN can't be recognized, or if the alternative can't be
+ determined.
+
+ Initialize the info in MATCHP based on the constraints. */
+
+static int
+find_matches (rtx insn, struct match *matchp)
+{
+ int likely_spilled[MAX_RECOG_OPERANDS];
+ int op_no;
+ int any_matches = 0;
+
+ extract_insn (insn);
+ if (! constrain_operands (0))
+ return 0;
+
+ /* Must initialize this before main loop, because the code for
+ the commutative case may set matches for operands other than
+ the current one. */
+ for (op_no = recog_data.n_operands; --op_no >= 0; )
+ matchp->with[op_no] = matchp->commutative[op_no] = -1;
+
+ for (op_no = 0; op_no < recog_data.n_operands; op_no++)
+ {
+ const char *p;
+ char c;
+ int i = 0;
+
+ p = recog_data.constraints[op_no];
+
+ likely_spilled[op_no] = 0;
+ matchp->use[op_no] = READ;
+ matchp->early_clobber[op_no] = 0;
+ if (*p == '=')
+ matchp->use[op_no] = WRITE;
+ else if (*p == '+')
+ matchp->use[op_no] = READWRITE;
+
+ for (;*p && i < which_alternative; p++)
+ if (*p == ',')
+ i++;
+
+ while ((c = *p) != '\0' && c != ',')
+ {
+ switch (c)
+ {
+ case '=':
+ break;
+ case '+':
+ break;
+ case '&':
+ matchp->early_clobber[op_no] = 1;
+ break;
+ case '%':
+ matchp->commutative[op_no] = op_no + 1;
+ matchp->commutative[op_no + 1] = op_no;
+ break;
+
+ case '0': case '1': case '2': case '3': case '4':
+ case '5': case '6': case '7': case '8': case '9':
+ {
+ char *end;
+ unsigned long match_ul = strtoul (p, &end, 10);
+ int match = match_ul;
+
+ p = end;
+
+ if (match < op_no && likely_spilled[match])
+ continue;
+ matchp->with[op_no] = match;
+ any_matches = 1;
+ if (matchp->commutative[op_no] >= 0)
+ matchp->with[matchp->commutative[op_no]] = match;
+ }
+ continue;
+
+ case 'a': case 'b': case 'c': case 'd': case 'e': case 'f': case 'h':
+ case 'j': case 'k': case 'l': case 'p': case 'q': case 't': case 'u':
+ case 'v': case 'w': case 'x': case 'y': case 'z': case 'A': case 'B':
+ case 'C': case 'D': case 'W': case 'Y': case 'Z':
+ if (targetm.class_likely_spilled_p (REG_CLASS_FROM_CONSTRAINT ((unsigned char) c, p)))
+ likely_spilled[op_no] = 1;
+ break;
+ }
+ p += CONSTRAINT_LEN (c, p);
+ }
+ }
+ return any_matches;
+}
+
+
+
+static bool
+gate_handle_regmove (void)
+{
+ return (optimize > 0 && flag_regmove);
+}
+
+
+struct rtl_opt_pass pass_regmove =
+{
+ {
+ RTL_PASS,
+ "regmove", /* name */
+ gate_handle_regmove, /* gate */
+ regmove_optimize, /* execute */
+ NULL, /* sub */
+ NULL, /* next */
+ 0, /* static_pass_number */
+ TV_REGMOVE, /* 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_flags_finish */
+ }
+};