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Diffstat (limited to 'contrib/gcc/regmove.c')
| -rw-r--r-- | contrib/gcc/regmove.c | 2190 |
1 files changed, 0 insertions, 2190 deletions
diff --git a/contrib/gcc/regmove.c b/contrib/gcc/regmove.c deleted file mode 100644 index 800859582c75..000000000000 --- a/contrib/gcc/regmove.c +++ /dev/null @@ -1,2190 +0,0 @@ -/* Move registers around to reduce number of move instructions needed. - Copyright (C) 1987, 88, 89, 92-98, 1999 Free Software Foundation, Inc. - -This file is part of GNU CC. - -GNU CC 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 2, or (at your option) -any later version. - -GNU CC 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 GNU CC; see the file COPYING. If not, write to -the Free Software Foundation, 59 Temple Place - Suite 330, -Boston, MA 02111-1307, USA. */ - - -/* This module looks for cases where matching constraints would force - an instruction to need a reload, and this reload would be a register - to register move. It then attempts to change the registers used by the - instruction to avoid the move instruction. */ - -#include "config.h" -#include "system.h" -#include "rtl.h" /* stdio.h must precede rtl.h for FFS. */ -#include "insn-config.h" -#include "recog.h" -#include "output.h" -#include "reload.h" -#include "regs.h" -#include "hard-reg-set.h" -#include "flags.h" -#include "expr.h" -#include "insn-flags.h" -#include "basic-block.h" -#include "toplev.h" - -static int optimize_reg_copy_1 PROTO((rtx, rtx, rtx)); -static void optimize_reg_copy_2 PROTO((rtx, rtx, rtx)); -static void optimize_reg_copy_3 PROTO((rtx, rtx, rtx)); -static rtx gen_add3_insn PROTO((rtx, rtx, rtx)); -static void copy_src_to_dest PROTO((rtx, rtx, rtx, int, int)); -static int *regmove_bb_head; - -struct match { - int with[MAX_RECOG_OPERANDS]; - enum { READ, WRITE, READWRITE } use[MAX_RECOG_OPERANDS]; - int commutative[MAX_RECOG_OPERANDS]; - int early_clobber[MAX_RECOG_OPERANDS]; -}; - -static rtx discover_flags_reg PROTO((void)); -static void mark_flags_life_zones PROTO((rtx)); -static void flags_set_1 PROTO((rtx, rtx)); - -static int try_auto_increment PROTO((rtx, rtx, rtx, rtx, HOST_WIDE_INT, int)); -static int find_matches PROTO((rtx, struct match *)); -static int fixup_match_1 PROTO((rtx, rtx, rtx, rtx, rtx, int, int, int, FILE *)) -; -static int reg_is_remote_constant_p PROTO((rtx, rtx, rtx)); -static int stable_and_no_regs_but_for_p PROTO((rtx, rtx, rtx)); -static int regclass_compatible_p PROTO((int, int)); -static int loop_depth; - -/* Return non-zero if registers with CLASS1 and CLASS2 can be merged without - causing too much register allocation problems. */ -static int -regclass_compatible_p (class0, class1) - int class0, class1; -{ - return (class0 == class1 - || (reg_class_subset_p (class0, class1) - && ! CLASS_LIKELY_SPILLED_P (class0)) - || (reg_class_subset_p (class1, class0) - && ! CLASS_LIKELY_SPILLED_P (class1))); -} - -/* Generate and return an insn body to add r1 and c, - storing the result in r0. */ -static rtx -gen_add3_insn (r0, r1, c) - rtx r0, r1, c; -{ - int icode = (int) add_optab->handlers[(int) GET_MODE (r0)].insn_code; - - if (icode == CODE_FOR_nothing - || ! (*insn_operand_predicate[icode][0]) (r0, insn_operand_mode[icode][0]) - || ! (*insn_operand_predicate[icode][1]) (r1, insn_operand_mode[icode][1]) - || ! (*insn_operand_predicate[icode][2]) (c, insn_operand_mode[icode][2])) - return NULL_RTX; - - return (GEN_FCN (icode) (r0, r1, c)); -} - - -/* 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 (insn, inc_insn, inc_insn_set, reg, increment, pre) - rtx reg, insn, inc_insn ,inc_insn_set; - 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) 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, Pmode, reg), 1); - if (apply_change_group ()) - { - REG_NOTES (insn) - = gen_rtx_EXPR_LIST (REG_INC, - reg, REG_NOTES (insn)); - if (! inc_insn_set) - { - PUT_CODE (inc_insn, NOTE); - NOTE_LINE_NUMBER (inc_insn) = NOTE_INSN_DELETED; - NOTE_SOURCE_FILE (inc_insn) = 0; - } - return 1; - } - } - } - } - return 0; -} - -/* Determine if the pattern generated by add_optab has a clobber, - such as might be issued for a flags hard register. To make the - code elsewhere simpler, we handle cc0 in this same framework. - - Return the register if one was discovered. Return NULL_RTX if - if no flags were found. Return pc_rtx if we got confused. */ - -static rtx -discover_flags_reg () -{ - rtx tmp; - tmp = gen_rtx_REG (word_mode, 10000); - tmp = gen_add3_insn (tmp, tmp, GEN_INT (2)); - - /* If we get something that isn't a simple set, or a - [(set ..) (clobber ..)], this whole function will go wrong. */ - if (GET_CODE (tmp) == SET) - return NULL_RTX; - else if (GET_CODE (tmp) == PARALLEL) - { - int found; - - if (XVECLEN (tmp, 0) != 2) - return pc_rtx; - tmp = XVECEXP (tmp, 0, 1); - if (GET_CODE (tmp) != CLOBBER) - return pc_rtx; - tmp = XEXP (tmp, 0); - - /* Don't do anything foolish if the md wanted to clobber a - scratch or something. We only care about hard regs. - Moreover we don't like the notion of subregs of hard regs. */ - if (GET_CODE (tmp) == SUBREG - && GET_CODE (SUBREG_REG (tmp)) == REG - && REGNO (SUBREG_REG (tmp)) < FIRST_PSEUDO_REGISTER) - return pc_rtx; - found = (GET_CODE (tmp) == REG && REGNO (tmp) < FIRST_PSEUDO_REGISTER); - - return (found ? tmp : NULL_RTX); - } - - return pc_rtx; -} - -/* It is a tedious task identifying when the flags register is live and - when it is safe to optimize. Since we process the instruction stream - multiple times, locate and record these live zones by marking the - mode of the instructions -- - - QImode is used on the instruction at which the flags becomes live. - - HImode is used within the range (exclusive) that the flags are - live. Thus the user of the flags is not marked. - - All other instructions are cleared to VOIDmode. */ - -/* Used to communicate with flags_set_1. */ -static rtx flags_set_1_rtx; -static int flags_set_1_set; - -static void -mark_flags_life_zones (flags) - rtx flags; -{ - int flags_regno; - int flags_nregs; - int block; - -#ifdef HAVE_cc0 - /* If we found a flags register on a cc0 host, bail. */ - if (flags == NULL_RTX) - flags = cc0_rtx; - else if (flags != cc0_rtx) - flags = pc_rtx; -#endif - - /* Simple cases first: if no flags, clear all modes. If confusing, - mark the entire function as being in a flags shadow. */ - if (flags == NULL_RTX || flags == pc_rtx) - { - enum machine_mode mode = (flags ? HImode : VOIDmode); - rtx insn; - for (insn = get_insns(); insn; insn = NEXT_INSN (insn)) - PUT_MODE (insn, mode); - return; - } - -#ifdef HAVE_cc0 - flags_regno = -1; - flags_nregs = 1; -#else - flags_regno = REGNO (flags); - flags_nregs = HARD_REGNO_NREGS (flags_regno, GET_MODE (flags)); -#endif - flags_set_1_rtx = flags; - - /* Process each basic block. */ - for (block = n_basic_blocks - 1; block >= 0; block--) - { - rtx insn, end; - int live; - - insn = BLOCK_HEAD (block); - end = BLOCK_END (block); - - /* Look out for the (unlikely) case of flags being live across - basic block boundaries. */ - live = 0; -#ifndef HAVE_cc0 - { - int i; - for (i = 0; i < flags_nregs; ++i) - live |= REGNO_REG_SET_P (BASIC_BLOCK (block)->global_live_at_start, - flags_regno + i); - } -#endif - - while (1) - { - /* Process liveness in reverse order of importance -- - alive, death, birth. This lets more important info - overwrite the mode of lesser info. */ - - if (GET_RTX_CLASS (GET_CODE (insn)) == 'i') - { -#ifdef HAVE_cc0 - /* In the cc0 case, death is not marked in reg notes, - but is instead the mere use of cc0 when it is alive. */ - if (live && reg_mentioned_p (cc0_rtx, PATTERN (insn))) - live = 0; -#else - /* In the hard reg case, we watch death notes. */ - if (live && find_regno_note (insn, REG_DEAD, flags_regno)) - live = 0; -#endif - PUT_MODE (insn, (live ? HImode : VOIDmode)); - - /* In either case, birth is denoted simply by it's presence - as the destination of a set. */ - flags_set_1_set = 0; - note_stores (PATTERN (insn), flags_set_1); - if (flags_set_1_set) - { - live = 1; - PUT_MODE (insn, QImode); - } - } - else - PUT_MODE (insn, (live ? HImode : VOIDmode)); - - if (insn == end) - break; - insn = NEXT_INSN (insn); - } - } -} - -/* A subroutine of mark_flags_life_zones, called through note_stores. */ - -static void -flags_set_1 (x, pat) - rtx x, pat; -{ - if (GET_CODE (pat) == SET - && reg_overlap_mentioned_p (x, flags_set_1_rtx)) - flags_set_1_set = 1; -} - -static int *regno_src_regno; - -/* Indicate how good a choice REG (which appears as a source) is to replace - a destination register with. The higher the returned value, the better - the choice. The main objective is to avoid using a register that is - a candidate for tying to a hard register, since the output might in - turn be a candidate to be tied to a different hard register. */ -int -replacement_quality(reg) - rtx reg; -{ - int src_regno; - - /* Bad if this isn't a register at all. */ - if (GET_CODE (reg) != REG) - return 0; - - /* If this register is not meant to get a hard register, - it is a poor choice. */ - if (REG_LIVE_LENGTH (REGNO (reg)) < 0) - return 0; - - src_regno = regno_src_regno[REGNO (reg)]; - - /* If it was not copied from another register, it is fine. */ - if (src_regno < 0) - return 3; - - /* Copied from a hard register? */ - if (src_regno < FIRST_PSEUDO_REGISTER) - return 1; - - /* Copied from a pseudo register - not as bad as from a hard register, - yet still cumbersome, since the register live length will be lengthened - when the registers get tied. */ - return 2; -} - -/* 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 (insn, dest, src) - rtx insn; - rtx dest; - rtx src; -{ - rtx p, q; - rtx note; - rtx dest_death = 0; - int sregno = REGNO (src); - int dregno = REGNO (dest); - - /* We don't want to mess with hard regs if register classes are small. */ - if (sregno == dregno - || (SMALL_REGISTER_CLASSES - && (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 (GET_CODE (p) == CODE_LABEL || GET_CODE (p) == JUMP_INSN - || (GET_CODE (p) == NOTE - && (NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_BEG - || NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_END))) - break; - - /* ??? We can't scan past the end of a basic block without updating - the register lifetime info (REG_DEAD/basic_block_live_at_start). - A CALL_INSN might be the last insn of a basic block, if it is inside - an EH region. There is no easy way to tell, so we just always break - when we see a CALL_INSN if flag_exceptions is nonzero. */ - if (flag_exceptions && GET_CODE (p) == CALL_INSN) - break; - - if (GET_RTX_CLASS (GET_CODE (p)) != 'i') - continue; - - if (reg_set_p (src, p) || reg_set_p (dest, p) - /* 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; - - /* 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; - - /* Replace all uses and make sure that the register - isn't still present. */ - else if (validate_replace_rtx (src, dest, q) - && (sregno >= FIRST_PSEUDO_REGISTER - || ! reg_overlap_mentioned_p (src, - PATTERN (q)))) - { - /* We assume that a register is used exactly once per - insn in the REG_N_REFS updates below. If this is not - correct, no great harm is done. - - Since we do not know if we will change the lifetime of - SREGNO or DREGNO, we must not update REG_LIVE_LENGTH - or REG_N_CALLS_CROSSED at this time. */ - if (sregno >= FIRST_PSEUDO_REGISTER) - REG_N_REFS (sregno) -= loop_depth; - - if (dregno >= FIRST_PSEUDO_REGISTER) - REG_N_REFS (dregno) += loop_depth; - } - else - { - 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. */ - 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 && GET_CODE (q) == CALL_INSN) - { - /* Similarly, total calls for SREGNO, total calls beyond - the death note for DREGNO. */ - s_n_calls++; - if (dest_death) - d_n_calls++; - } - - /* 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; - } - - /* Move death note of SRC from P to INSN. */ - remove_note (p, note); - XEXP (note, 1) = REG_NOTES (insn); - REG_NOTES (insn) = note; - } - - /* 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; - } - } - - 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 (insn, dest, src) - rtx insn; - rtx dest; - rtx src; -{ - rtx p, q; - rtx set; - int sregno = REGNO (src); - int dregno = REGNO (dest); - - for (p = NEXT_INSN (insn); p; p = NEXT_INSN (p)) - { - if (GET_CODE (p) == CODE_LABEL || GET_CODE (p) == JUMP_INSN - || (GET_CODE (p) == NOTE - && (NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_BEG - || NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_END))) - break; - - /* ??? We can't scan past the end of a basic block without updating - the register lifetime info (REG_DEAD/basic_block_live_at_start). - A CALL_INSN might be the last insn of a basic block, if it is inside - an EH region. There is no easy way to tell, so we just always break - when we see a CALL_INSN if flag_exceptions is nonzero. */ - if (flag_exceptions && GET_CODE (p) == CALL_INSN) - break; - - if (GET_RTX_CLASS (GET_CODE (p)) != 'i') - continue; - - 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 (GET_RTX_CLASS (GET_CODE (q)) == 'i') - { - if (reg_mentioned_p (dest, PATTERN (q))) - { - PATTERN (q) = replace_rtx (PATTERN (q), dest, src); - - /* We assume that a register is used exactly once per - insn in the updates below. If this is not correct, - no great harm is done. */ - REG_N_REFS (dregno) -= loop_depth; - REG_N_REFS (sregno) += loop_depth; - } - - - if (GET_CODE (q) == CALL_INSN) - { - REG_N_CALLS_CROSSED (dregno)--; - REG_N_CALLS_CROSSED (sregno)++; - } - } - - 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) - || (GET_CODE (p) == CALL_INSN && 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 encorporate 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 (insn, dest, src) - 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, subreg; - enum machine_mode old_mode; - - if (src_no < FIRST_PSEUDO_REGISTER - || dst_no < FIRST_PSEUDO_REGISTER - || ! find_reg_note (insn, REG_DEAD, src_reg) - || REG_N_SETS (src_no) != 1) - return; - for (p = PREV_INSN (insn); ! reg_set_p (src_reg, p); p = PREV_INSN (p)) - { - if (GET_CODE (p) == CODE_LABEL || GET_CODE (p) == JUMP_INSN - || (GET_CODE (p) == NOTE - && (NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_BEG - || NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_END))) - return; - - /* ??? We can't scan past the end of a basic block without updating - the register lifetime info (REG_DEAD/basic_block_live_at_start). - A CALL_INSN might be the last insn of a basic block, if it is inside - an EH region. There is no easy way to tell, so we just always break - when we see a CALL_INSN if flag_exceptions is nonzero. */ - if (flag_exceptions && GET_CODE (p) == CALL_INSN) - return; - - if (GET_RTX_CLASS (GET_CODE (p)) != 'i') - continue; - } - if (! (set = single_set (p)) - || GET_CODE (SET_SRC (set)) != MEM - || SET_DEST (set) != src_reg) - return; - - /* Be conserative: 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 (GET_MODE_BITSIZE (GET_MODE (src)), - GET_MODE_BITSIZE (GET_MODE (src_reg)))) - return; - - 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. */ - subreg = gen_rtx_SUBREG (old_mode, src_reg, 0); - while (p = NEXT_INSN (p), p != insn) - { - if (GET_RTX_CLASS (GET_CODE (p)) != 'i') - continue; - - /* Make a tenative change. */ - validate_replace_rtx_group (src_reg, subreg, 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; - } -} - - -/* 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 (insn, src, dest, loop_depth, old_max_uid) - rtx insn; - rtx src; - rtx dest; - int loop_depth; - int old_max_uid; -{ - 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; - int bb; - int insn_uid; - int move_uid; - - /* 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 (GET_CODE (src) == REG - && REG_LIVE_LENGTH (REGNO (src)) > 0 - && GET_CODE (dest) == REG - && 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 = gen_sequence (); - 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 = ®_NOTES (move_insn); - p_insn_notes = ®_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; - - /* Is the insn the head of a basic block? If so extend it */ - insn_uid = INSN_UID (insn); - move_uid = INSN_UID (move_insn); - if (insn_uid < old_max_uid) - { - bb = regmove_bb_head[insn_uid]; - if (bb >= 0) - { - BLOCK_HEAD (bb) = move_insn; - regmove_bb_head[insn_uid] = -1; - } - } - - /* Update the various register tables. */ - dest_regno = REGNO (dest); - REG_N_SETS (dest_regno) += loop_depth; - REG_N_REFS (dest_regno) += loop_depth; - REG_LIVE_LENGTH (dest_regno)++; - if (REGNO_FIRST_UID (dest_regno) == insn_uid) - REGNO_FIRST_UID (dest_regno) = move_uid; - - src_regno = REGNO (src); - if (! find_reg_note (move_insn, REG_DEAD, src)) - REG_LIVE_LENGTH (src_regno)++; - - if (REGNO_FIRST_UID (src_regno) == insn_uid) - REGNO_FIRST_UID (src_regno) = move_uid; - - if (REGNO_LAST_UID (src_regno) == insn_uid) - REGNO_LAST_UID (src_regno) = move_uid; - - if (REGNO_LAST_NOTE_UID (src_regno) == insn_uid) - REGNO_LAST_NOTE_UID (src_regno) = move_uid; - } -} - - -/* 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?). FIRST is - the first insn in the function. */ - -static int -reg_is_remote_constant_p (reg, insn, first) - rtx reg; - rtx insn; - rtx first; -{ - register rtx p; - - if (REG_N_SETS (REGNO (reg)) != 1) - return 0; - - /* Look for the set. */ - for (p = LOG_LINKS (insn); p; p = XEXP (p, 1)) - { - rtx s; - - if (REG_NOTE_KIND (p) != 0) - continue; - s = single_set (XEXP (p, 0)); - if (s != 0 - && GET_CODE (SET_DEST (s)) == REG - && REGNO (SET_DEST (s)) == REGNO (reg)) - { - /* The register is set in the same basic block. */ - return 0; - } - } - - for (p = first; p && p != insn; p = NEXT_INSN (p)) - { - rtx s; - - if (GET_RTX_CLASS (GET_CODE (p)) != 'i') - continue; - s = single_set (p); - if (s != 0 - && GET_CODE (SET_DEST (s)) == REG - && REGNO (SET_DEST (s)) == REGNO (reg)) - { - /* This is the instruction which sets REG. If there is a - REG_EQUAL note, then REG is equivalent to a constant. */ - if (find_reg_note (p, REG_EQUAL, NULL_RTX)) - return 1; - return 0; - } - } - - return 0; -} - -/* 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 squences when it finds a - hard register as ultimate source, like the frame pointer. */ - -int -fixup_match_2 (insn, dst, src, offset, regmove_dump_file) - rtx insn, dst, src, offset; - FILE *regmove_dump_file; -{ - rtx p, dst_death = 0; - int length, num_calls = 0; - - /* 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 (GET_CODE (p) == CODE_LABEL - || GET_CODE (p) == JUMP_INSN - || (GET_CODE (p) == NOTE - && (NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_BEG - || NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_END))) - break; - - /* ??? We can't scan past the end of a basic block without updating - the register lifetime info (REG_DEAD/basic_block_live_at_start). - A CALL_INSN might be the last insn of a basic block, if it is inside - an EH region. There is no easy way to tell, so we just always break - when we see a CALL_INSN if flag_exceptions is nonzero. */ - if (flag_exceptions && GET_CODE (p) == CALL_INSN) - break; - - if (GET_RTX_CLASS (GET_CODE (p)) != 'i') - continue; - - if (find_regno_note (p, REG_DEAD, REGNO (dst))) - dst_death = p; - if (! dst_death) - length++; - - pset = single_set (p); - if (pset && SET_DEST (pset) == dst - && GET_CODE (SET_SRC (pset)) == PLUS - && XEXP (SET_SRC (pset), 0) == src - && GET_CODE (XEXP (SET_SRC (pset), 1)) == CONST_INT) - { - 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_N_REFS (REGNO (dst)) += loop_depth; - REG_N_REFS (REGNO (src)) -= loop_depth; - - if (regmove_dump_file) - fprintf (regmove_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 (GET_CODE (p) == CODE_LABEL - || GET_CODE (p) == JUMP_INSN - || (GET_CODE (p) == NOTE - && (NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_BEG - || NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_END))) - break; - if (GET_RTX_CLASS (GET_CODE (p)) != 'i') - continue; - 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 (GET_CODE (p) == CODE_LABEL - || GET_CODE (p) == JUMP_INSN - || (GET_CODE (p) == NOTE - && (NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_BEG - || NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_END))) - break; - if (GET_RTX_CLASS (GET_CODE (p)) != 'i') - continue; - 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 (GET_CODE (p) == CALL_INSN) - { - if (! dst_death) - num_calls++; - - if (REG_N_CALLS_CROSSED (REGNO (src)) == 0) - break; - - if (call_used_regs [REGNO (dst)] - || find_reg_fusage (p, CLOBBER, dst)) - break; - } - else if (reg_set_p (src, PATTERN (p))) - break; - } - - return 0; -} - -void -regmove_optimize (f, nregs, regmove_dump_file) - rtx f; - int nregs; - FILE *regmove_dump_file; -{ - int old_max_uid = get_max_uid (); - rtx insn; - struct match match; - int pass; - int i; - rtx copy_src, copy_dst; - - /* Find out where a potential flags register is live, and so that we - can supress some optimizations in those zones. */ - mark_flags_life_zones (discover_flags_reg ()); - - regno_src_regno = (int *)alloca (sizeof *regno_src_regno * nregs); - for (i = nregs; --i >= 0; ) regno_src_regno[i] = -1; - - regmove_bb_head = (int *)alloca (sizeof (int) * (old_max_uid + 1)); - for (i = old_max_uid; i >= 0; i--) regmove_bb_head[i] = -1; - for (i = 0; i < n_basic_blocks; i++) - regmove_bb_head[INSN_UID (BLOCK_HEAD (i))] = i; - - /* A forward/backward pass. Replace output operands with input operands. */ - - loop_depth = 1; - - for (pass = 0; pass <= 2; pass++) - { - if (! flag_regmove && pass >= flag_expensive_optimizations) - return; - - if (regmove_dump_file) - fprintf (regmove_dump_file, "Starting %s pass...\n", - pass ? "backward" : "forward"); - - for (insn = pass ? get_last_insn () : f; insn; - insn = pass ? PREV_INSN (insn) : NEXT_INSN (insn)) - { - rtx set; - int op_no, match_no; - - if (GET_CODE (insn) == NOTE) - { - if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG) - loop_depth++; - else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END) - loop_depth--; - } - - set = single_set (insn); - if (! set) - continue; - - if (flag_expensive_optimizations && ! pass - && (GET_CODE (SET_SRC (set)) == SIGN_EXTEND - || GET_CODE (SET_SRC (set)) == ZERO_EXTEND) - && GET_CODE (XEXP (SET_SRC (set), 0)) == REG - && GET_CODE (SET_DEST(set)) == REG) - optimize_reg_copy_3 (insn, SET_DEST (set), SET_SRC (set)); - - if (flag_expensive_optimizations && ! pass - && GET_CODE (SET_SRC (set)) == REG - && GET_CODE (SET_DEST(set)) == REG) - { - /* 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; - } - } - } - if (! flag_regmove) - continue; - -#ifdef REGISTER_CONSTRAINTS - if (! find_matches (insn, &match)) - continue; - - /* Now scan through the operands looking for a source operand - which is supposed to match the destination operand. - Then scan forward for an instruction which uses the dest - operand. - If it dies there, then replace the dest in both operands with - the source operand. */ - - for (op_no = 0; op_no < recog_n_operands; op_no++) - { - rtx src, dst, src_subreg; - enum reg_class src_class, dst_class; - - match_no = match.with[op_no]; - - /* Nothing to do if the two operands aren't supposed to match. */ - if (match_no < 0) - continue; - - src = recog_operand[op_no]; - dst = recog_operand[match_no]; - - if (GET_CODE (src) != REG) - continue; - - src_subreg = src; - if (GET_CODE (dst) == SUBREG - && GET_MODE_SIZE (GET_MODE (dst)) - >= GET_MODE_SIZE (GET_MODE (SUBREG_REG (dst)))) - { - src_subreg - = gen_rtx_SUBREG (GET_MODE (SUBREG_REG (dst)), - src, SUBREG_WORD (dst)); - dst = SUBREG_REG (dst); - } - if (GET_CODE (dst) != REG - || REGNO (dst) < FIRST_PSEUDO_REGISTER) - continue; - - if (REGNO (src) < FIRST_PSEUDO_REGISTER) - { - if (match.commutative[op_no] < op_no) - regno_src_regno[REGNO (dst)] = REGNO (src); - continue; - } - - if (REG_LIVE_LENGTH (REGNO (src)) < 0) - continue; - - /* op_no/src must be a read-only operand, and - match_operand/dst must be a write-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) > 1) - continue; - - /* Make sure match_operand is the destination. */ - if (recog_operand[match_no] != SET_DEST (set)) - continue; - - /* If the operands already match, then there is nothing to do. */ - /* But in the commutative case, we might find a better match. */ - if (operands_match_p (src, dst) - || (match.commutative[op_no] >= 0 - && operands_match_p (recog_operand[match.commutative - [op_no]], dst) - && (replacement_quality (recog_operand[match.commutative - [op_no]]) - >= replacement_quality (src)))) - continue; - - src_class = reg_preferred_class (REGNO (src)); - dst_class = reg_preferred_class (REGNO (dst)); - if (! regclass_compatible_p (src_class, dst_class)) - continue; - - if (fixup_match_1 (insn, set, src, src_subreg, dst, pass, - op_no, match_no, - regmove_dump_file)) - break; - } - } - } - - /* A backward pass. Replace input operands with output operands. */ - - if (regmove_dump_file) - fprintf (regmove_dump_file, "Starting backward pass...\n"); - - loop_depth = 1; - - for (insn = get_last_insn (); insn; insn = PREV_INSN (insn)) - { - if (GET_CODE (insn) == NOTE) - { - if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END) - loop_depth++; - else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG) - loop_depth--; - } - if (GET_RTX_CLASS (GET_CODE (insn)) == 'i') - { - int op_no, match_no; - int success = 0; - - 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_n_operands; op_no++) - { - rtx set, p, src, dst; - rtx src_note, dst_note; - int num_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_operand[match_no]; - src = recog_operand[op_no]; - - if (GET_CODE (src) != REG) - continue; - - if (GET_CODE (dst) != REG - || REGNO (dst) < FIRST_PSEUDO_REGISTER - || REG_LIVE_LENGTH (REGNO (dst)) < 0) - continue; - - /* If the operands already match, then there is nothing to do. */ - if (operands_match_p (src, dst) - || (match.commutative[op_no] >= 0 - && operands_match_p (recog_operand[match.commutative[op_no]], dst))) - continue; - - set = single_set (insn); - if (! set) - 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) > 1) - continue; - - /* Make sure match_no is the destination. */ - if (recog_operand[match_no] != SET_DEST (set)) - continue; - - if (REGNO (src) < FIRST_PSEUDO_REGISTER) - { - if (GET_CODE (SET_SRC (set)) == PLUS - && GET_CODE (XEXP (SET_SRC (set), 1)) == CONST_INT - && XEXP (SET_SRC (set), 0) == src - && fixup_match_2 (insn, dst, src, - XEXP (SET_SRC (set), 1), - regmove_dump_file)) - break; - continue; - } - src_class = reg_preferred_class (REGNO (src)); - dst_class = reg_preferred_class (REGNO (dst)); - 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_note = find_reg_note (insn, REG_DEAD, src))) - { - 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, f)) - { - if (!copy_src) - { - copy_src = src; - copy_dst = dst; - } - continue; - } - - - if (regmove_dump_file) - fprintf (regmove_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 (GET_CODE (p) == CODE_LABEL - || GET_CODE (p) == JUMP_INSN - || (GET_CODE (p) == NOTE - && (NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_BEG - || NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_END))) - break; - - /* ??? We can't scan past the end of a basic block without - updating the register lifetime info - (REG_DEAD/basic_block_live_at_start). - A CALL_INSN might be the last insn of a basic block, if - it is inside an EH region. There is no easy way to tell, - so we just always break when we see a CALL_INSN if - flag_exceptions is nonzero. */ - if (flag_exceptions && GET_CODE (p) == CALL_INSN) - break; - - if (GET_RTX_CLASS (GET_CODE (p)) != 'i') - continue; - - 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. */ - if (validate_replace_rtx (src, dst, insn)) - { - if (validate_change (p, &SET_DEST (pset), - dst, 0)) - success = 1; - else - { - /* Change all source operands back. - This modifies the dst as a side-effect. */ - validate_replace_rtx (dst, src, insn); - /* Now make sure the dst is right. */ - validate_change (insn, - recog_operand_loc[match_no], - dst, 0); - } - } - break; - } - - if (reg_overlap_mentioned_p (src, PATTERN (p)) - || reg_overlap_mentioned_p (dst, PATTERN (p))) - 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 (GET_CODE (p) == CALL_INSN) - { - num_calls++; - - 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); - - REG_N_SETS (dstno)++; - REG_N_SETS (srcno)--; - - REG_N_CALLS_CROSSED (dstno) += num_calls; - REG_N_CALLS_CROSSED (srcno) -= num_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; - } - - /* We assume that a register is used exactly once per - insn in the updates above. If this is not correct, - no great harm is done. */ - - REG_N_REFS (dstno) += 2 * loop_depth; - REG_N_REFS (srcno) -= 2 * loop_depth; - - /* If that was the only time src was set, - and src was not live at the start of the - function, we know that we have no more - references to src; clear REG_N_REFS so it - won't make reload do any work. */ - if (REG_N_SETS (REGNO (src)) == 0 - && ! regno_uninitialized (REGNO (src))) - REG_N_REFS (REGNO (src)) = 0; - - if (regmove_dump_file) - fprintf (regmove_dump_file, - "Fixed operand %d of insn %d matching operand %d.\n", - op_no, INSN_UID (insn), match_no); - - break; - } - } - - /* If we weren't able to replace any of the alternatives, try an - alternative appoach of copying the source to the destination. */ - if (!success && copy_src != NULL_RTX) - copy_src_to_dest (insn, copy_src, copy_dst, loop_depth, - old_max_uid); - - } - } -#endif /* REGISTER_CONSTRAINTS */ - - /* In fixup_match_1, some insns may have been inserted after basic block - ends. Fix that here. */ - for (i = 0; i < n_basic_blocks; i++) - { - rtx end = BLOCK_END (i); - rtx new = end; - rtx next = NEXT_INSN (new); - while (next != 0 && INSN_UID (next) >= old_max_uid - && (i == n_basic_blocks - 1 || BLOCK_HEAD (i + 1) != next)) - new = next, next = NEXT_INSN (new); - BLOCK_END (i) = new; - } -} - -/* 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 (insn, matchp) - 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_n_operands; --op_no >= 0; ) - matchp->with[op_no] = matchp->commutative[op_no] = -1; - - for (op_no = 0; op_no < recog_n_operands; op_no++) - { - const char *p; - char c; - int i = 0; - - p = recog_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': - c -= '0'; - if (c < op_no && likely_spilled[(unsigned char) c]) - break; - matchp->with[op_no] = c; - any_matches = 1; - if (matchp->commutative[op_no] >= 0) - matchp->with[matchp->commutative[op_no]] = c; - break; - 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 (CLASS_LIKELY_SPILLED_P (REG_CLASS_FROM_LETTER ((unsigned char)c))) - likely_spilled[op_no] = 1; - break; - } - } - return any_matches; -} - -/* Try to replace output operand DST in SET, with input operand SRC. SET is - the only set in INSN. INSN has just been recgnized and constrained. - SRC is operand number OPERAND_NUMBER in INSN. - DST is operand number MATCH_NUMBER in INSN. - If BACKWARD is nonzero, we have been called in a backward pass. - Return nonzero for success. */ -static int -fixup_match_1 (insn, set, src, src_subreg, dst, backward, operand_number, - match_number, regmove_dump_file) - rtx insn, set, src, src_subreg, dst; - int backward, operand_number, match_number; - FILE *regmove_dump_file; -{ - rtx p; - rtx post_inc = 0, post_inc_set = 0, search_end = 0; - int success = 0; - int num_calls = 0, s_num_calls = 0; - enum rtx_code code = NOTE; - HOST_WIDE_INT insn_const, newconst; - rtx overlap = 0; /* need to move insn ? */ - rtx src_note = find_reg_note (insn, REG_DEAD, src), dst_note; - int length, s_length, true_loop_depth; - - /* If SRC is marked as unchanging, we may not change it. - ??? Maybe we could get better code by removing the unchanging bit - instead, and changing it back if we don't succeed? */ - if (RTX_UNCHANGING_P (src)) - return 0; - - if (! src_note) - { - /* Look for (set (regX) (op regA constX)) - (set (regY) (op regA constY)) - and change that to - (set (regA) (op regA constX)). - (set (regY) (op regA constY-constX)). - This works for add and shift operations, if - regA is dead after or set by the second insn. */ - - code = GET_CODE (SET_SRC (set)); - if ((code == PLUS || code == LSHIFTRT - || code == ASHIFT || code == ASHIFTRT) - && XEXP (SET_SRC (set), 0) == src - && GET_CODE (XEXP (SET_SRC (set), 1)) == CONST_INT) - insn_const = INTVAL (XEXP (SET_SRC (set), 1)); - else if (! stable_and_no_regs_but_for_p (SET_SRC (set), src, dst)) - return 0; - else - /* We might find a src_note while scanning. */ - code = NOTE; - } - - if (regmove_dump_file) - fprintf (regmove_dump_file, - "Could fix operand %d of insn %d matching operand %d.\n", - operand_number, INSN_UID (insn), match_number); - - /* If SRC is equivalent to a constant set in a different basic block, - then do not use it for this optimization. We want the equivalence - so that if we have to reload this register, we can reload the - constant, rather than extending the lifespan of the register. */ - if (reg_is_remote_constant_p (src, insn, get_insns ())) - return 0; - - /* Scan forward to find the next instruction that - uses the output operand. If the operand dies here, - then replace it in both instructions with - operand_number. */ - - for (length = s_length = 0, p = NEXT_INSN (insn); p; p = NEXT_INSN (p)) - { - if (GET_CODE (p) == CODE_LABEL || GET_CODE (p) == JUMP_INSN - || (GET_CODE (p) == NOTE - && (NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_BEG - || NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_END))) - break; - - /* ??? We can't scan past the end of a basic block without updating - the register lifetime info (REG_DEAD/basic_block_live_at_start). - A CALL_INSN might be the last insn of a basic block, if it is - inside an EH region. There is no easy way to tell, so we just - always break when we see a CALL_INSN if flag_exceptions is nonzero. */ - if (flag_exceptions && GET_CODE (p) == CALL_INSN) - break; - - if (GET_RTX_CLASS (GET_CODE (p)) != 'i') - continue; - - length++; - if (src_note) - s_length++; - - if (reg_set_p (src, p) || reg_set_p (dst, p) - || (GET_CODE (PATTERN (p)) == USE - && reg_overlap_mentioned_p (src, XEXP (PATTERN (p), 0)))) - break; - - /* See if all of DST dies in P. This test is - slightly more conservative than it needs to be. */ - if ((dst_note = find_regno_note (p, REG_DEAD, REGNO (dst))) - && (GET_MODE (XEXP (dst_note, 0)) == GET_MODE (dst))) - { - if (! src_note) - { - rtx q; - rtx set2; - - /* If an optimization is done, the value of SRC while P - is executed will be changed. Check that this is OK. */ - if (reg_overlap_mentioned_p (src, PATTERN (p))) - break; - for (q = p; q; q = NEXT_INSN (q)) - { - if (GET_CODE (q) == CODE_LABEL || GET_CODE (q) == JUMP_INSN - || (GET_CODE (q) == NOTE - && (NOTE_LINE_NUMBER (q) == NOTE_INSN_LOOP_BEG - || NOTE_LINE_NUMBER (q) == NOTE_INSN_LOOP_END))) - { - q = 0; - break; - } - - /* ??? We can't scan past the end of a basic block without - updating the register lifetime info - (REG_DEAD/basic_block_live_at_start). - A CALL_INSN might be the last insn of a basic block, if - it is inside an EH region. There is no easy way to tell, - so we just always break when we see a CALL_INSN if - flag_exceptions is nonzero. */ - if (flag_exceptions && GET_CODE (q) == CALL_INSN) - { - q = 0; - break; - } - - if (GET_RTX_CLASS (GET_CODE (q)) != 'i') - continue; - if (reg_overlap_mentioned_p (src, PATTERN (q)) - || reg_set_p (src, q)) - break; - } - if (q) - set2 = single_set (q); - if (! q || ! set2 || GET_CODE (SET_SRC (set2)) != code - || XEXP (SET_SRC (set2), 0) != src - || GET_CODE (XEXP (SET_SRC (set2), 1)) != CONST_INT - || (SET_DEST (set2) != src - && ! find_reg_note (q, REG_DEAD, src))) - { - /* If this is a PLUS, we can still save a register by doing - src += insn_const; - P; - src -= insn_const; . - This also gives opportunities for subsequent - optimizations in the backward pass, so do it there. */ - if (code == PLUS && backward - /* Don't do this if we can likely tie DST to SET_DEST - of P later; we can't do this tying here if we got a - hard register. */ - && ! (dst_note && ! REG_N_CALLS_CROSSED (REGNO (dst)) - && single_set (p) - && GET_CODE (SET_DEST (single_set (p))) == REG - && (REGNO (SET_DEST (single_set (p))) - < FIRST_PSEUDO_REGISTER)) - /* We may only emit an insn directly after P if we - are not in the shadow of a live flags register. */ - && GET_MODE (p) == VOIDmode) - { - search_end = q; - q = insn; - set2 = set; - newconst = -insn_const; - code = MINUS; - } - else - break; - } - else - { - newconst = INTVAL (XEXP (SET_SRC (set2), 1)) - insn_const; - /* Reject out of range shifts. */ - if (code != PLUS - && (newconst < 0 - || (newconst - >= GET_MODE_BITSIZE (GET_MODE (SET_SRC (set2)))))) - break; - if (code == PLUS) - { - post_inc = q; - if (SET_DEST (set2) != src) - post_inc_set = set2; - } - } - /* We use 1 as last argument to validate_change so that all - changes are accepted or rejected together by apply_change_group - when it is called by validate_replace_rtx . */ - validate_change (q, &XEXP (SET_SRC (set2), 1), - GEN_INT (newconst), 1); - } - validate_change (insn, recog_operand_loc[match_number], src, 1); - if (validate_replace_rtx (dst, src_subreg, p)) - success = 1; - break; - } - - if (reg_overlap_mentioned_p (dst, PATTERN (p))) - break; - if (! src_note && reg_overlap_mentioned_p (src, PATTERN (p))) - { - /* INSN was already checked to be movable when - we found no REG_DEAD note for src on it. */ - overlap = p; - src_note = find_reg_note (p, REG_DEAD, src); - } - - /* 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. */ - if (GET_CODE (p) == CALL_INSN) - { - if (REG_N_CALLS_CROSSED (REGNO (src)) == 0) - break; - - num_calls++; - - if (src_note) - s_num_calls++; - - } - } - - if (! success) - return 0; - - true_loop_depth = backward ? 2 - loop_depth : loop_depth; - - /* Remove the death note for DST from P. */ - remove_note (p, dst_note); - if (code == MINUS) - { - post_inc = emit_insn_after (copy_rtx (PATTERN (insn)), p); - if ((HAVE_PRE_INCREMENT || HAVE_PRE_DECREMENT) - && search_end - && try_auto_increment (search_end, post_inc, 0, src, newconst, 1)) - post_inc = 0; - validate_change (insn, &XEXP (SET_SRC (set), 1), GEN_INT (insn_const), 0); - REG_N_SETS (REGNO (src))++; - REG_N_REFS (REGNO (src)) += true_loop_depth; - REG_LIVE_LENGTH (REGNO (src))++; - } - if (overlap) - { - /* The lifetime of src and dest overlap, - but we can change this by moving insn. */ - rtx pat = PATTERN (insn); - if (src_note) - remove_note (overlap, src_note); - if ((HAVE_POST_INCREMENT || HAVE_POST_DECREMENT) - && code == PLUS - && try_auto_increment (overlap, insn, 0, src, insn_const, 0)) - insn = overlap; - else - { - rtx notes = REG_NOTES (insn); - - emit_insn_after_with_line_notes (pat, PREV_INSN (p), insn); - PUT_CODE (insn, NOTE); - NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED; - NOTE_SOURCE_FILE (insn) = 0; - /* emit_insn_after_with_line_notes has no - return value, so search for the new insn. */ - for (insn = p; PATTERN (insn) != pat; ) - insn = PREV_INSN (insn); - - REG_NOTES (insn) = notes; - } - } - /* Sometimes we'd generate src = const; src += n; - if so, replace the instruction that set src - in the first place. */ - - if (! overlap && (code == PLUS || code == MINUS)) - { - rtx note = find_reg_note (insn, REG_EQUAL, NULL_RTX); - rtx q, set2; - int num_calls2 = 0, s_length2 = 0; - - if (note && CONSTANT_P (XEXP (note, 0))) - { - for (q = PREV_INSN (insn); q; q = PREV_INSN(q)) - { - if (GET_CODE (q) == CODE_LABEL || GET_CODE (q) == JUMP_INSN - || (GET_CODE (q) == NOTE - && (NOTE_LINE_NUMBER (q) == NOTE_INSN_LOOP_BEG - || NOTE_LINE_NUMBER (q) == NOTE_INSN_LOOP_END))) - { - q = 0; - break; - } - - /* ??? We can't scan past the end of a basic block without - updating the register lifetime info - (REG_DEAD/basic_block_live_at_start). - A CALL_INSN might be the last insn of a basic block, if - it is inside an EH region. There is no easy way to tell, - so we just always break when we see a CALL_INSN if - flag_exceptions is nonzero. */ - if (flag_exceptions && GET_CODE (q) == CALL_INSN) - { - q = 0; - break; - } - - if (GET_RTX_CLASS (GET_CODE (q)) != 'i') - continue; - s_length2++; - if (reg_set_p (src, q)) - { - set2 = single_set (q); - break; - } - if (reg_overlap_mentioned_p (src, PATTERN (q))) - { - q = 0; - break; - } - if (GET_CODE (p) == CALL_INSN) - num_calls2++; - } - if (q && set2 && SET_DEST (set2) == src && CONSTANT_P (SET_SRC (set2)) - && validate_change (insn, &SET_SRC (set), XEXP (note, 0), 0)) - { - PUT_CODE (q, NOTE); - NOTE_LINE_NUMBER (q) = NOTE_INSN_DELETED; - NOTE_SOURCE_FILE (q) = 0; - REG_N_SETS (REGNO (src))--; - REG_N_CALLS_CROSSED (REGNO (src)) -= num_calls2; - REG_N_REFS (REGNO (src)) -= true_loop_depth; - REG_LIVE_LENGTH (REGNO (src)) -= s_length2; - insn_const = 0; - } - } - } - - if ((HAVE_PRE_INCREMENT || HAVE_PRE_DECREMENT) - && (code == PLUS || code == MINUS) && insn_const - && try_auto_increment (p, insn, 0, src, insn_const, 1)) - insn = p; - else if ((HAVE_POST_INCREMENT || HAVE_POST_DECREMENT) - && post_inc - && try_auto_increment (p, post_inc, post_inc_set, src, newconst, 0)) - post_inc = 0; - /* If post_inc still prevails, try to find an - insn where it can be used as a pre-in/decrement. - If code is MINUS, this was already tried. */ - if (post_inc && code == PLUS - /* Check that newconst is likely to be usable - in a pre-in/decrement before starting the search. */ - && ((HAVE_PRE_INCREMENT && newconst > 0 && newconst <= MOVE_MAX) - || (HAVE_PRE_DECREMENT && newconst < 0 && newconst >= -MOVE_MAX)) - && exact_log2 (newconst)) - { - rtx q, inc_dest; - - inc_dest = post_inc_set ? SET_DEST (post_inc_set) : src; - for (q = post_inc; (q = NEXT_INSN (q)); ) - { - if (GET_CODE (q) == CODE_LABEL || GET_CODE (q) == JUMP_INSN - || (GET_CODE (q) == NOTE - && (NOTE_LINE_NUMBER (q) == NOTE_INSN_LOOP_BEG - || NOTE_LINE_NUMBER (q) == NOTE_INSN_LOOP_END))) - break; - - /* ??? We can't scan past the end of a basic block without updating - the register lifetime info (REG_DEAD/basic_block_live_at_start). - A CALL_INSN might be the last insn of a basic block, if it - is inside an EH region. There is no easy way to tell so we - just always break when we see a CALL_INSN if flag_exceptions - is nonzero. */ - if (flag_exceptions && GET_CODE (q) == CALL_INSN) - break; - - if (GET_RTX_CLASS (GET_CODE (q)) != 'i') - continue; - if (src != inc_dest && (reg_overlap_mentioned_p (src, PATTERN (q)) - || reg_set_p (src, q))) - break; - if (reg_set_p (inc_dest, q)) - break; - if (reg_overlap_mentioned_p (inc_dest, PATTERN (q))) - { - try_auto_increment (q, post_inc, - post_inc_set, inc_dest, newconst, 1); - break; - } - } - } - /* Move the death note for DST to INSN if it is used - there. */ - if (reg_overlap_mentioned_p (dst, PATTERN (insn))) - { - XEXP (dst_note, 1) = REG_NOTES (insn); - REG_NOTES (insn) = dst_note; - } - - if (src_note) - { - /* Move the death note for SRC from INSN to P. */ - if (! overlap) - remove_note (insn, src_note); - XEXP (src_note, 1) = REG_NOTES (p); - REG_NOTES (p) = src_note; - - REG_N_CALLS_CROSSED (REGNO (src)) += s_num_calls; - } - - REG_N_SETS (REGNO (src))++; - REG_N_SETS (REGNO (dst))--; - - REG_N_CALLS_CROSSED (REGNO (dst)) -= num_calls; - - REG_LIVE_LENGTH (REGNO (src)) += s_length; - if (REG_LIVE_LENGTH (REGNO (dst)) >= 0) - { - REG_LIVE_LENGTH (REGNO (dst)) -= 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 (REGNO (dst)) < 2) - REG_LIVE_LENGTH (REGNO (dst)) = 2; - } - - /* We assume that a register is used exactly once per - insn in the updates above. If this is not correct, - no great harm is done. */ - - REG_N_REFS (REGNO (src)) += 2 * true_loop_depth; - REG_N_REFS (REGNO (dst)) -= 2 * true_loop_depth; - - /* If that was the only time dst was set, - and dst was not live at the start of the - function, we know that we have no more - references to dst; clear REG_N_REFS so it - won't make reload do any work. */ - if (REG_N_SETS (REGNO (dst)) == 0 - && ! regno_uninitialized (REGNO (dst))) - REG_N_REFS (REGNO (dst)) = 0; - - if (regmove_dump_file) - fprintf (regmove_dump_file, - "Fixed operand %d of insn %d matching operand %d.\n", - operand_number, INSN_UID (insn), match_number); - return 1; -} - - -/* return nonzero if X is stable and mentions no regsiters but for - mentioning SRC or mentioning / changing DST . If in doubt, presume - it is unstable. - The rationale is that we want to check if we can move an insn easily - while just paying attention to SRC and DST. A register is considered - stable if it has the RTX_UNCHANGING_P bit set, but that would still - leave the burden to update REG_DEAD / REG_UNUSED notes, so we don't - want any registers but SRC and DST. */ -static int -stable_and_no_regs_but_for_p (x, src, dst) - rtx x, src, dst; -{ - RTX_CODE code = GET_CODE (x); - switch (GET_RTX_CLASS (code)) - { - case '<': case '1': case 'c': case '2': case 'b': case '3': - { - int i; - char *fmt = GET_RTX_FORMAT (code); - for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) - if (fmt[i] == 'e' - && ! stable_and_no_regs_but_for_p (XEXP (x, i), src, dst)) - return 0; - return 1; - } - case 'o': - if (code == REG) - return x == src || x == dst; - /* If this is a MEM, look inside - there might be a register hidden in - the address of an unchanging MEM. */ - if (code == MEM - && ! stable_and_no_regs_but_for_p (XEXP (x, 0), src, dst)) - return 0; - /* fall through */ - default: - return ! rtx_unstable_p (x); - } -} - -/* Test if regmove seems profitable for this target. Regmove is useful only - if some common patterns are two address, i.e. require matching constraints, - so we check that condition here. */ - -int -regmove_profitable_p () -{ -#ifdef REGISTER_CONSTRAINTS - struct match match; - enum machine_mode mode; - optab tstoptab = add_optab; - do /* check add_optab and ashl_optab */ - for (mode = GET_CLASS_NARROWEST_MODE (MODE_INT); mode != VOIDmode; - mode = GET_MODE_WIDER_MODE (mode)) - { - int icode = (int) tstoptab->handlers[(int) mode].insn_code; - rtx reg0, reg1, reg2, pat; - int i; - - if (GET_MODE_BITSIZE (mode) < 32 || icode == CODE_FOR_nothing) - continue; - for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) - if (TEST_HARD_REG_BIT (reg_class_contents[GENERAL_REGS], i)) - break; - if (i + 2 >= FIRST_PSEUDO_REGISTER) - break; - reg0 = gen_rtx_REG (insn_operand_mode[icode][0], i); - reg1 = gen_rtx_REG (insn_operand_mode[icode][1], i + 1); - reg2 = gen_rtx_REG (insn_operand_mode[icode][2], i + 2); - if (! (*insn_operand_predicate[icode][0]) (reg0, VOIDmode) - || ! (*insn_operand_predicate[icode][1]) (reg1, VOIDmode) - || ! (*insn_operand_predicate[icode][2]) (reg2, VOIDmode)) - break; - pat = GEN_FCN (icode) (reg0, reg1, reg2); - if (! pat) - continue; - if (GET_CODE (pat) == SEQUENCE) - pat = XVECEXP (pat, 0, XVECLEN (pat, 0) - 1); - else - pat = make_insn_raw (pat); - if (! single_set (pat) - || GET_CODE (SET_SRC (single_set (pat))) != tstoptab->code) - /* Unexpected complexity; don't need to handle this unless - we find a machine where this occurs and regmove should - be enabled. */ - break; - if (find_matches (pat, &match)) - return 1; - break; - } - while (tstoptab != ashl_optab && (tstoptab = ashl_optab, 1)); -#endif /* REGISTER_CONSTRAINTS */ - return 0; -} |