/* Move registers around to reduce number of move instructions needed. Copyright (C) 1998 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" #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" /* Static nesting depth within loops; 1 is the top level. */ static int loop_depth; /* ??? Missing documenation on this variable. */ static int *regno_src_regno; /* Defines the uses of each operand. */ enum operand_use {READ, WRITE, READWRITE}; /* This structure describes the usage of operands. WITH indicates which operand (-1 for none) an operand matches with. COMMUTATIVE indicates which operand (-1 for none) and operand is commutative with. USE tells whether the operand is read, written, or both. EARLY_CLOBBER, if nonzero, indicates that the operand is an output that can be written before all inputs are used. */ struct match { int with[MAX_RECOG_OPERANDS]; enum operand_use use[MAX_RECOG_OPERANDS]; int commutative[MAX_RECOG_OPERANDS]; int early_clobber[MAX_RECOG_OPERANDS]; }; static rtx next_insn_for_regmove PROTO((rtx)); static rtx prev_insn_for_regmove PROTO((rtx)); static int try_auto_increment PROTO((rtx, rtx, rtx, rtx, HOST_WIDE_INT, int)); static int replacement_quality PROTO((rtx)); 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_extend PROTO((rtx, rtx, rtx)); static int reg_is_remote_constant_p PROTO((rtx, rtx, rtx)); static int merge_additions PROTO((rtx, rtx, rtx, rtx, FILE *)); static int find_matches PROTO((rtx, struct match *)); static int fixup_match PROTO((rtx, rtx, rtx, rtx, rtx, int, int, int, FILE *)); static int stable_but_for_p PROTO((rtx, rtx, rtx)); /* Get next (previous) insn we consider. We only return something that's an insn, but do not cross a basic block or loop boundary. Note that if basic block boundaries change, this code must change as well. */ static rtx next_insn_for_regmove (insn) rtx insn; { while (insn != 0) { insn = NEXT_INSN (insn); if (insn == 0 || GET_CODE (insn) == CODE_LABEL || GET_CODE (insn) == JUMP_INSN || (GET_CODE (insn) == NOTE && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END))) return 0; if (GET_RTX_CLASS (GET_CODE (insn)) == 'i') break; } return insn; } static rtx prev_insn_for_regmove (insn) rtx insn; { while (insn != 0) { insn = PREV_INSN (insn); if (insn == 0 || GET_CODE (insn) == CODE_LABEL || GET_CODE (insn) == JUMP_INSN || (GET_CODE (insn) == NOTE && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END))) return 0; if (GET_RTX_CLASS (GET_CODE (insn)) == 'i') break; } return insn; } #ifdef AUTO_INC_DEC /* INC_INSN is an instruction that adds INCREMENT to REG. If PRE is nonzero, the addition was before INSN, after if it was zero. If INC_SET is nonzero, it is the SET within INC_INSN that does the incrementing and it is not to be deleted; otherwise, INC_INSN has no effect other than doing the specified increment. Try to replace INC_INSN with a post/pre in/decrement inside INSN. Return nonzero if we were able to do the replacement. If INC_SET is nonzero, its source is replaced by REG; otherwise INC_INSN is deleted. */ static int try_auto_increment (insn, inc_insn, inc_set, reg, increment, pre) rtx insn; rtx inc_insn; rtx inc_set; rtx reg; HOST_WIDE_INT increment; int pre; { enum rtx_code inc_code; rtx pset, use; int size; /* There must be exactly one usage of REG as an address inside INSN, which also must have only one set. Then get the size of the memory. We must do it this way since some insns (such as extensions) have mixed modes within SET_SRC. */ if ((pset = single_set (insn)) == 0 || (use = find_use_as_address (pset, reg, 0)) == 0 || use == (rtx) 1) return 0; size = GET_MODE_SIZE (GET_MODE (use)); if (0 #ifdef HAVE_POST_INCREMENT || (pre == 0 && (inc_code = POST_INC, increment == size)) #endif #ifdef HAVE_PRE_INCREMENT || (pre == 1 && (inc_code = PRE_INC, increment == size)) #endif #ifdef HAVE_POST_DECREMENT || (pre == 0 && (inc_code = POST_DEC, increment == - size)) #endif #ifdef HAVE_PRE_DECREMENT || (pre == 1 && (inc_code = PRE_DEC, increment == - size)) #endif ) { /* Make sure we can do any needed replacement before changing anything. */ if (inc_set != 0) validate_change (inc_insn, &SET_SRC (inc_set), reg, 1); validate_change (insn, &XEXP (use, 0), gen_rtx (inc_code, GET_MODE (reg), reg), 1); if (! apply_change_group ()) return 0; REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_INC, reg, REG_NOTES (insn)); if (inc_set == 0) { PUT_CODE (inc_insn, NOTE); NOTE_LINE_NUMBER (inc_insn) = NOTE_INSN_DELETED; NOTE_SOURCE_FILE (inc_insn) = 0; } return 1; } return 0; } #endif /* AUTO_INC_DEC */ /* 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. */ static 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. Return 1 if we were able to perform this optimization. */ 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_for_regmove (insn); p != 0; p = next_insn_for_regmove (p)) { 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 length = 0; int d_length = 0; int n_calls = 0; int d_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 updates below. If this is not correct, no great harm is done. */ 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; } } /* Count the insns and CALL_INSNs passed. If we passed the death note of DEST, show increased live length. */ 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) { 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) { if (sregno >= FIRST_PSEUDO_REGISTER) { if (REG_LIVE_LENGTH (sregno) >= 0) { REG_LIVE_LENGTH (sregno) -= 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) -= n_calls; } if (dregno >= FIRST_PSEUDO_REGISTER) { if (REG_LIVE_LENGTH (dregno) >= 0) REG_LIVE_LENGTH (dregno) += d_length; REG_N_CALLS_CROSSED (dregno) += d_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; } 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_for_regmove (insn); p != 0; p = next_insn_for_regmove (p)) { 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 contains a single which is a ZERO_ or SIGN_EXTEND. See if its souce dies there and if it is only set once, by a load from memory. If so, try to incorporate the zero/sign extension into the memory read, change the source to the mode of the destination, and alter the remaining accesses to use the appropriate SUBREG. This allows the two registers to be tied later. */ static void optimize_reg_extend (insn, set) rtx insn; rtx set; { rtx src = SET_SRC (set); rtx src_reg = XEXP (src, 0); int src_no = REGNO (src_reg); enum machine_mode old_mode = GET_MODE (src_reg); rtx p, p_set, subreg; if (REGNO (src_reg) < FIRST_PSEUDO_REGISTER || REGNO (SET_DEST (set)) < FIRST_PSEUDO_REGISTER || ! find_reg_note (insn, REG_DEAD, src_reg) || REG_N_SETS (REGNO (src_reg)) != 1) return; /* Find the previous insn we are allowed to consider that sets SRC_REG. */ for (p = prev_insn_for_regmove (insn); p != 0; p = prev_insn_for_regmove (p)) if (reg_set_p (src_reg, p)) break; if (p == 0 || (p_set = single_set (p)) == 0 || GET_CODE (SET_SRC (p_set)) != MEM || SET_DEST (p_set) != src_reg) return; /* Change SRC_REG to be the extended mode, change the insn we found to extend from memory, and change out SET to use the extended form. */ PUT_MODE (src_reg, GET_MODE (src)); validate_change (p, &SET_SRC (p_set), gen_rtx (GET_CODE (src), GET_MODE (src), src_reg), 1); validate_change (insn, &SET_SRC (set), src_reg, 1); if (! apply_change_group ()) { PUT_MODE (src_reg, old_mode); return; } subreg = gen_lowpart (old_mode, src_reg); for (; p != insn; p = next_real_insn (p)) validate_replace_rtx (src_reg, subreg, p); } /* Return nonzero if 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; { rtx p; if (REG_N_SETS (REGNO (reg)) != 1) return 0; /* Look for the set. */ for (p = LOG_LINKS (insn); p != 0; p = XEXP (p, 1)) { rtx s; if (REG_NOTE_KIND (p) != 0) continue; if ((s = single_set (XEXP (p, 0))) != 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 != 0 && p != insn; p = NEXT_INSN (p)) { rtx s; if (GET_RTX_CLASS (GET_CODE (p)) != 'i') continue; if ((s = single_set (p)) != 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. */ return find_reg_note (p, REG_EQUAL, NULL_RTX) != 0; } return 0; } /* INSN is adding OFFSET, a CONST_INT, to SRC, a REG, to produe DST, also a REG. Search backwards looking for another add immediate insn with the same source and destination registers. If we find one, change INSN to have the same input and output register, but with an adjusted constant, and return 1. If no changes are made, return 0. This changes (set (reg0) (plus reg1 offset1)) ... (set (reg0) (plus reg1 offset2)) to (set (reg0) (plus reg1 offset1)) ... (set (reg0) (plus reg0 offset2-offset1)) */ static int merge_additions (insn, dst, src, offset, regmove_dump_file) rtx insn; rtx dst; rtx src; rtx 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 more work than worthwhile, so skip the optimization in this case. */ if (find_regno_note (insn, REG_DEAD, REGNO (src)) /* We don't want to mess with hard regs if register classes are small. */ || (SMALL_REGISTER_CLASSES && (REGNO (src) < FIRST_PSEUDO_REGISTER || REGNO (dst) < 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. */ || src == stack_pointer_rtx || dst == stack_pointer_rtx) return 0; /* Scan backward to find the first instruction that sets DST. */ for (length = 0, p = prev_insn_for_regmove (insn); p != 0; p = prev_insn_for_regmove (insn)) { rtx pset; if (find_regno_note (p, REG_DEAD, REGNO (dst))) dst_death = p; if (dst_death == 0) length++; if ((pset = single_set (p)) != 0 && rtx_equal_p (SET_DEST (pset), dst) && GET_CODE (SET_SRC (pset)) == PLUS && rtx_equal_p (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)); enum insn_code icode = add_optab->handlers[(int) GET_MODE (dst)].insn_code; rtx newpat = GEN_FCN (icode) (dst, dst, GEN_INT (newconst)); if (newpat != 0 && validate_change (insn, &PATTERN (insn), newpat, 0)) { /* Remove the death note for DST from DST_DEATH. */ if (dst_death != 0) { 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 /* Now that we've changed this insn, see if that produces any auto-increment opportunities. Try in both directions. Stop after we've made one. */ for (p = prev_insn_for_regmove (insn); p != 0; p = prev_insn_for_regmove (p)) 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_for_regmove (insn); p != 0; p = next_insn_for_regmove (p)) 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, don't perform the optimization. reg_set_p is overly conservative for CALL_INSNS and 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 == 0) 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; } /* Returns the INSN_CODE for INSN if its pattern has matching constraints for any operand. Returns -1 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 operand_number; int insn_code_number = recog_memoized (insn); int any_matches = 0; if (insn_code_number < 0) return -1; insn_extract (insn); if (! constrain_operands (insn_code_number, 0)) return -1; /* Must initialize this before main loop, because the code for the commutative case may set matches for operands other than the current one. */ for (operand_number = insn_n_operands[insn_code_number]; --operand_number >= 0; ) matchp->with[operand_number] = matchp->commutative[operand_number] = -1; for (operand_number = 0; operand_number < insn_n_operands[insn_code_number]; operand_number++) { char *p = insn_operand_constraint[insn_code_number][operand_number]; int i = 0; char c; likely_spilled[operand_number] = 0; matchp->use[operand_number] = READ; matchp->early_clobber[operand_number] = 0; /* Constraint letters for read and read/write are global. All others are per-constraint. */ if (*p == '=') matchp->use[operand_number] = WRITE; else if (*p == '+') matchp->use[operand_number] = READWRITE; for (; *p != '\0' && i < which_alternative; p++) if (*p == ',') i++; /* Process each constraint letter for the alternative that this insn matches, if it matches one yet. */ while ((c = *p++) != '\0' && c != ',') switch (c) { case '=': case '+': case '?': case '*': case '#': case 'X': case 'm': case '<': case '>': case 'o': case 'V': case 'E': case 'F': case 'G': case 'H': case 's': case 'n': case 'I': case 'J': case 'K': case 'L': case 'M': case 'N': case 'O': case 'P': #ifdef EXTRA_CONSTRAINT case 'Q': case 'R': case 'S': case 'T': case 'U': #endif break; case '&': matchp->early_clobber[operand_number] = 1; break; case '%': matchp->commutative[operand_number] = operand_number + 1; matchp->commutative[operand_number + 1] = operand_number; 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 < operand_number && likely_spilled[c]) break; matchp->with[operand_number] = c; any_matches = 1; if (matchp->commutative[operand_number] >= 0) matchp->with[matchp->commutative[operand_number]] = c; break; case 'g': case 'r': if (CLASS_LIKELY_SPILLED_P (GENERAL_REGS)) likely_spilled[operand_number] = 1; break; default: if (CLASS_LIKELY_SPILLED_P (REG_CLASS_FROM_LETTER (c))) likely_spilled[operand_number] = 1; break; } } return any_matches ? insn_code_number : -1; } /* 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. All registers are known to be pseudo-registers. Return nonzero for success. */ static int fixup_match (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 src_note = find_reg_note (insn, REG_DEAD, src); rtx post_inc = 0, post_inc_set = 0, search_end = 0; rtx overlap = 0; int success = 0; int num_calls = 0, s_num_calls = 0; enum rtx_code code = NOTE; HOST_WIDE_INT insn_const, newconst; rtx dst_note; rtx p; int length, s_length, true_loop_depth; if (src_note == 0) { /* 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) && rtx_equal_p (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_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_for_regmove (insn); p != 0; p = next_insn_for_regmove (p)) { length++; if (src_note != 0) 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))) != 0 && (GET_MODE (XEXP (dst_note, 0)) == GET_MODE (dst))) { if (src_note == 0) { 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 != 0; q = next_insn_for_regmove (q)) if (reg_overlap_mentioned_p (src, PATTERN (q)) || reg_set_p (src, q)) break; if (q != 0) set2 = single_set (q); if (q == 0 || set2 == 0 || GET_CODE (SET_SRC (set2)) != code || ! rtx_equal_p (XEXP (SET_SRC (set2), 0), src) || GET_CODE (XEXP (SET_SRC (set2), 1)) != CONST_INT || (! rtx_equal_p (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 #ifdef HAVE_cc0 /* We may not emit an insn directly after P if the latter sets CC0. */ && ! sets_cc0_p (PATTERN (p)) #endif ) { 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 (! rtx_equal_p (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 below 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 == 0 && 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 defined (HAVE_PRE_INCREMENT) || defined (HAVE_PRE_DECREMENT) if (search_end && try_auto_increment (search_end, post_inc, 0, src, newconst, 1)) post_inc = 0; #endif 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 != 0) remove_note (overlap, src_note); #if defined (HAVE_POST_INCREMENT) || defined (HAVE_POST_DECREMENT) if (code == PLUS && try_auto_increment (overlap, insn, 0, src, insn_const, 0)) insn = overlap; else #endif { 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 != 0 && CONSTANT_P (XEXP (note, 0))) { for (q = prev_insn_for_regmove (insn); q != 0; q = prev_insn_for_regmove (q)) { 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 != 0 && set2 != 0 && rtx_equal_p (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; } } } /* Don't remove this seemingly useless if, it is needed to pair with the else in the next two conditionally included code blocks. */ if (0) {;} #if defined (HAVE_PRE_INCREMENT) || defined (HAVE_PRE_DECREMENT) else if ((code == PLUS || code == MINUS) && insn_const && try_auto_increment (p, insn, 0, src, insn_const, 1)) insn = p; #endif #if defined (HAVE_POST_INCREMENT) || defined (HAVE_POST_DECREMENT) else if (post_inc && try_auto_increment (p, post_inc, post_inc_set, src, newconst, 0)) post_inc = 0; #endif #if defined (HAVE_PRE_INCREMENT) || defined (HAVE_PRE_DECREMENT) /* 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. */ && (0 #if defined (HAVE_PRE_INCREMENT) || (newconst > 0 && newconst <= MOVE_MAX) #endif #if defined (HAVE_PRE_DECREMENT) || (newconst < 0 && newconst >= -MOVE_MAX) #endif ) && exact_log2 (newconst)) { rtx q, inc_dest; inc_dest = post_inc_set ? SET_DEST (post_inc_set) : src; for (q = next_insn_for_regmove (post_inc); q != 0; q = next_insn_for_regmove (q)) { if (! rtx_equal_p (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; } } } #endif /* defined (HAVE_PRE_INCREMENT) || defined (HAVE_PRE_DECREMENT) */ /* 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 != 0) { /* 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 except for mentioning SRC or mentioning and/or changing DST. If in doubt, presume it is unstable. */ static int stable_but_for_p (x, src, dst) rtx x; rtx src; rtx dst; { enum 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_but_for_p (XEXP (x, i), src, dst)) return 0; return 1; } case 'o': if (x == src || x == dst) return 1; /* ... fall through ... */ default: return ! rtx_unstable_p (x); } } /* This is the main routine for this file. */ void regmove_optimize (f, nregs, regmove_dump_file) rtx f; int nregs; FILE *regmove_dump_file; { rtx insn; struct match match; int pass; int maxregnum = max_reg_num (), i; regno_src_regno = (int *) alloca (sizeof *regno_src_regno * maxregnum); for (i = maxregnum; --i >= 0; ) regno_src_regno[i] = -1; /* Alternate between forward and backward passes, replacing 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 insn_code_number; int operand_number, match_number; 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--; } if ((set = single_set (insn)) == 0) 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_extend (insn, 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; } } } #ifdef REGISTER_CONSTRAINTS insn_code_number = find_matches (insn, &match); if (insn_code_number < 0) continue; /* Now scan through the operands looking for a source operand that is supposed to match the destination operand. Then scan forward for an instruction which uses the destination operand. If it dies there, replace the destination in both operands with the source operand. */ for (operand_number = 0; operand_number < insn_n_operands[insn_code_number]; operand_number++) { rtx src, dst, src_subreg; enum reg_class src_class, dst_class; match_number = match.with[operand_number]; if (match_number < 0) continue; src = recog_operand[operand_number]; dst = recog_operand[match_number]; 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[operand_number] < operand_number) regno_src_regno[REGNO (dst)] = REGNO (src); continue; } if (REG_LIVE_LENGTH (REGNO (src)) < 0) continue; /* operand_number/src must be a read-only operand, and match_operand/dst must be a write-only operand. */ if (match.use[operand_number] != READ || match.use[match_number] != WRITE) continue; if (match.early_clobber[match_number] && count_occurrences (PATTERN (insn), src) > 1) continue; /* Make sure match_operand is the destination. */ if (recog_operand[match_number] != SET_DEST (set)) continue; /* If the operands already match, there is nothing to do. But in the commutative case, we might find a better match. */ if (operands_match_p (src, dst) || (match.commutative[operand_number] >= 0 && operands_match_p (recog_operand[match.commutative [operand_number]], dst) && (replacement_quality (recog_operand[match.commutative [operand_number]]) >= replacement_quality (src)))) continue; src_class = reg_preferred_class (REGNO (src)); dst_class = reg_preferred_class (REGNO (dst)); if (src_class != dst_class && (! reg_class_subset_p (src_class, dst_class) || CLASS_LIKELY_SPILLED_P (src_class)) && (! reg_class_subset_p (dst_class, src_class) || CLASS_LIKELY_SPILLED_P (dst_class))) continue; if (fixup_match (insn, set, src, src_subreg, dst, pass, operand_number, match_number, 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 insn_code_number = find_matches (insn, &match); int operand_number, match_number; if (insn_code_number < 0) continue; /* Scan through the operands looking for a destination operand that is supposed to match a source operand. Then scan backward for an insn that sets the source operand. If safe, replace the source operand with the destination operand in both insns. */ for (operand_number = 0; operand_number < insn_n_operands[insn_code_number]; operand_number++) { rtx set, p, src, dst; rtx src_note, dst_note; int success = 0; int num_calls = 0; enum reg_class src_class, dst_class; int length; match_number = match.with[operand_number]; if (match_number < 0) continue; dst = recog_operand[match_number]; src = recog_operand[operand_number]; 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, there is nothing to do. */ if (operands_match_p (src, dst) || (match.commutative[operand_number] >= 0 && (operands_match_p (recog_operand[match.commutative[operand_number]], dst)))) continue; if ((set = single_set (insn)) == 0) continue; /* match_number/dst must be a write-only operand, and operand_operand/src must be a read-only operand. */ if (match.use[operand_number] != READ || match.use[match_number] != WRITE) continue; if (match.early_clobber[match_number] && count_occurrences (PATTERN (insn), src) > 1) continue; /* Make sure match_number is the destination. */ if (recog_operand[match_number] != 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 && merge_additions (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 (src_class != dst_class && (! reg_class_subset_p (src_class, dst_class) || CLASS_LIKELY_SPILLED_P (src_class)) && (! reg_class_subset_p (dst_class, src_class) || CLASS_LIKELY_SPILLED_P (dst_class))) continue; if ((src_note = find_reg_note (insn, REG_DEAD, src)) == 0) 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))) continue; if (regmove_dump_file) fprintf (regmove_dump_file, "Could fix operand %d of insn %d matching op %d.\n", operand_number, INSN_UID (insn), match_number); /* If src is set once in a different basic block and is set equal to a constant, do not use it for this optimization, as this would make it no longer equivalent to the constant. */ if (reg_is_remote_constant_p (src, insn, f)) continue; /* 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_number. */ 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; 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. */ if ((pset = single_set (p))!= 0 && 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_number], 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 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 op %d.\n", operand_number, INSN_UID (insn), match_number); break; } } } } #endif /* REGISTER_CONSTRAINTS */ } /* 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. This can only be called after we can allocate RTL. */ int regmove_profitable_p () { #ifdef REGISTER_CONSTRAINTS struct match match; enum machine_mode mode; optab tstoptab = add_optab; char *free_point = (char *) oballoc (0); 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); /* Use CONST_INT for a shift since some machines do odd things in the register case (e.g., PA). */ if (tstoptab->code == ASHIFT) reg2 = const1_rtx; else 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 == 0) 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) >= 0) { obfree (free_point); return 1; } break; } while (tstoptab != ashl_optab && (tstoptab = ashl_optab, 1)); obfree (free_point); #endif /* REGISTER_CONSTRAINTS */ return 0; }