diff options
Diffstat (limited to 'gcc/regmove.c')
| -rw-r--r-- | gcc/regmove.c | 864 |
1 files changed, 129 insertions, 735 deletions
diff --git a/gcc/regmove.c b/gcc/regmove.c index 12b93fc..ce55c14 100644 --- a/gcc/regmove.c +++ b/gcc/regmove.c @@ -20,10 +20,8 @@ along with GCC; see the file COPYING3. If not see <http://www.gnu.org/licenses/>. */ -/* 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. */ +/* This module makes some simple RTL code transformations which + improve the subsequent register allocation. */ #include "config.h" #include "system.h" @@ -64,13 +62,8 @@ static rtx discover_flags_reg (void); static void mark_flags_life_zones (rtx); static void flags_set_1 (rtx, const_rtx, void *); -static int try_auto_increment (rtx, rtx, rtx, rtx, HOST_WIDE_INT, int); static int find_matches (rtx, struct match *); -static void replace_in_call_usage (rtx *, unsigned int, rtx, rtx); -static int fixup_match_1 (rtx, rtx, rtx, rtx, rtx, int, int, int); -static int stable_and_no_regs_but_for_p (rtx, rtx, rtx); static int regclass_compatible_p (int, int); -static int replacement_quality (rtx); static int fixup_match_2 (rtx, rtx, rtx, rtx); /* Return nonzero if registers with CLASS1 and CLASS2 can be merged without @@ -85,132 +78,6 @@ regclass_compatible_p (int class0, int class1) && ! CLASS_LIKELY_SPILLED_P (class1))); } -/* Find the place in the rtx X where REG is used as a memory address. - Return the MEM rtx that so uses it. - If PLUSCONST is nonzero, search instead for a memory address equivalent to - (plus REG (const_int PLUSCONST)). - - If such an address does not appear, return 0. - If REG appears more than once, or is used other than in such an address, - return (rtx) 1. */ - -static rtx -find_use_as_address (rtx x, rtx reg, HOST_WIDE_INT plusconst) -{ - enum rtx_code code = GET_CODE (x); - const char * const fmt = GET_RTX_FORMAT (code); - int i; - rtx value = 0; - rtx tem; - - if (code == MEM && XEXP (x, 0) == reg && plusconst == 0) - return x; - - if (code == MEM && GET_CODE (XEXP (x, 0)) == PLUS - && XEXP (XEXP (x, 0), 0) == reg - && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT - && INTVAL (XEXP (XEXP (x, 0), 1)) == plusconst) - return x; - - if (code == SIGN_EXTRACT || code == ZERO_EXTRACT) - { - /* If REG occurs inside a MEM used in a bit-field reference, - that is unacceptable. */ - if (find_use_as_address (XEXP (x, 0), reg, 0) != 0) - return (rtx) (size_t) 1; - } - - if (x == reg) - return (rtx) (size_t) 1; - - for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) - { - if (fmt[i] == 'e') - { - tem = find_use_as_address (XEXP (x, i), reg, plusconst); - if (value == 0) - value = tem; - else if (tem != 0) - return (rtx) (size_t) 1; - } - else if (fmt[i] == 'E') - { - int j; - for (j = XVECLEN (x, i) - 1; j >= 0; j--) - { - tem = find_use_as_address (XVECEXP (x, i, j), reg, plusconst); - if (value == 0) - value = tem; - else if (tem != 0) - return (rtx) (size_t) 1; - } - } - } - - return value; -} - - -/* INC_INSN is an instruction that adds INCREMENT to REG. - Try to fold INC_INSN as a post/pre in/decrement into INSN. - Iff INC_INSN_SET is nonzero, inc_insn has a destination different from src. - Return nonzero for success. */ -static int -try_auto_increment (rtx insn, rtx inc_insn, rtx inc_insn_set, rtx reg, - HOST_WIDE_INT increment, int pre) -{ - enum rtx_code inc_code; - - rtx pset = single_set (insn); - if (pset) - { - /* Can't use the size of SET_SRC, we might have something like - (sign_extend:SI (mem:QI ... */ - rtx use = find_use_as_address (pset, reg, 0); - if (use != 0 && use != (rtx) (size_t) 1) - { - int size = GET_MODE_SIZE (GET_MODE (use)); - if (0 - || (HAVE_POST_INCREMENT - && pre == 0 && (inc_code = POST_INC, increment == size)) - || (HAVE_PRE_INCREMENT - && pre == 1 && (inc_code = PRE_INC, increment == size)) - || (HAVE_POST_DECREMENT - && pre == 0 && (inc_code = POST_DEC, increment == -size)) - || (HAVE_PRE_DECREMENT - && pre == 1 && (inc_code = PRE_DEC, increment == -size)) - ) - { - if (inc_insn_set) - validate_change - (inc_insn, - &SET_SRC (inc_insn_set), - XEXP (SET_SRC (inc_insn_set), 0), 1); - validate_change (insn, &XEXP (use, 0), - gen_rtx_fmt_e (inc_code, Pmode, reg), 1); - if (apply_change_group ()) - { - /* If there is a REG_DEAD note on this insn, we must - change this not to REG_UNUSED meaning that the register - is set, but the value is dead. Failure to do so will - result in sched1 dying -- when it recomputes lifetime - information, the number of REG_DEAD notes will have - changed. */ - rtx note = find_reg_note (insn, REG_DEAD, reg); - if (note) - PUT_MODE (note, REG_UNUSED); - - add_reg_note (insn, REG_INC, reg); - - if (! inc_insn_set) - delete_insn (inc_insn); - 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 @@ -376,43 +243,140 @@ flags_set_1 (rtx x, const_rtx pat, void *data ATTRIBUTE_UNUSED) && 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. */ -static int -replacement_quality (rtx reg) +#ifdef AUTO_INC_DEC + +/* Find the place in the rtx X where REG is used as a memory address. + Return the MEM rtx that so uses it. + If PLUSCONST is nonzero, search instead for a memory address equivalent to + (plus REG (const_int PLUSCONST)). + + If such an address does not appear, return 0. + If REG appears more than once, or is used other than in such an address, + return (rtx) 1. */ + +static rtx +find_use_as_address (rtx x, rtx reg, HOST_WIDE_INT plusconst) { - int src_regno; + enum rtx_code code = GET_CODE (x); + const char * const fmt = GET_RTX_FORMAT (code); + int i; + rtx value = 0; + rtx tem; - /* Bad if this isn't a register at all. */ - if (!REG_P (reg)) - return 0; + if (code == MEM && XEXP (x, 0) == reg && plusconst == 0) + return x; - /* 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; + if (code == MEM && GET_CODE (XEXP (x, 0)) == PLUS + && XEXP (XEXP (x, 0), 0) == reg + && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT + && INTVAL (XEXP (XEXP (x, 0), 1)) == plusconst) + return x; - src_regno = regno_src_regno[REGNO (reg)]; + if (code == SIGN_EXTRACT || code == ZERO_EXTRACT) + { + /* If REG occurs inside a MEM used in a bit-field reference, + that is unacceptable. */ + if (find_use_as_address (XEXP (x, 0), reg, 0) != 0) + return (rtx) (size_t) 1; + } - /* If it was not copied from another register, it is fine. */ - if (src_regno < 0) - return 3; + if (x == reg) + return (rtx) (size_t) 1; - /* Copied from a hard register? */ - if (src_regno < FIRST_PSEUDO_REGISTER) - return 1; + for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) + { + if (fmt[i] == 'e') + { + tem = find_use_as_address (XEXP (x, i), reg, plusconst); + if (value == 0) + value = tem; + else if (tem != 0) + return (rtx) (size_t) 1; + } + else if (fmt[i] == 'E') + { + int j; + for (j = XVECLEN (x, i) - 1; j >= 0; j--) + { + tem = find_use_as_address (XVECEXP (x, i, j), reg, plusconst); + if (value == 0) + value = tem; + else if (tem != 0) + return (rtx) (size_t) 1; + } + } + } - /* 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; + return value; } + + +/* INC_INSN is an instruction that adds INCREMENT to REG. + Try to fold INC_INSN as a post/pre in/decrement into INSN. + Iff INC_INSN_SET is nonzero, inc_insn has a destination different from src. + Return nonzero for success. */ +static int +try_auto_increment (rtx insn, rtx inc_insn, rtx inc_insn_set, rtx reg, + HOST_WIDE_INT increment, int pre) +{ + enum rtx_code inc_code; + + rtx pset = single_set (insn); + if (pset) + { + /* Can't use the size of SET_SRC, we might have something like + (sign_extend:SI (mem:QI ... */ + rtx use = find_use_as_address (pset, reg, 0); + if (use != 0 && use != (rtx) (size_t) 1) + { + int size = GET_MODE_SIZE (GET_MODE (use)); + if (0 + || (HAVE_POST_INCREMENT + && pre == 0 && (inc_code = POST_INC, increment == size)) + || (HAVE_PRE_INCREMENT + && pre == 1 && (inc_code = PRE_INC, increment == size)) + || (HAVE_POST_DECREMENT + && pre == 0 && (inc_code = POST_DEC, increment == -size)) + || (HAVE_PRE_DECREMENT + && pre == 1 && (inc_code = PRE_DEC, increment == -size)) + ) + { + if (inc_insn_set) + validate_change + (inc_insn, + &SET_SRC (inc_insn_set), + XEXP (SET_SRC (inc_insn_set), 0), 1); + validate_change (insn, &XEXP (use, 0), + gen_rtx_fmt_e (inc_code, Pmode, reg), 1); + if (apply_change_group ()) + { + /* If there is a REG_DEAD note on this insn, we must + change this not to REG_UNUSED meaning that the register + is set, but the value is dead. Failure to do so will + result in sched1 dying -- when it recomputes lifetime + information, the number of REG_DEAD notes will have + changed. */ + rtx note = find_reg_note (insn, REG_DEAD, reg); + if (note) + PUT_MODE (note, REG_UNUSED); + + add_reg_note (insn, REG_INC, reg); + + if (! inc_insn_set) + delete_insn (inc_insn); + return 1; + } + } + } + } + return 0; +} +#endif + + +static int *regno_src_regno; + /* Return 1 if INSN might end a basic block. */ @@ -898,7 +862,7 @@ copy_src_to_dest (rtx insn, rtx src, rtx dest) /* reg_set_in_bb[REGNO] points to basic block iff the register is set only once in the given block and has REG_EQUAL note. */ -basic_block *reg_set_in_bb; +static basic_block *reg_set_in_bb; /* Size of reg_set_in_bb array. */ static unsigned int max_reg_computed; @@ -1126,7 +1090,7 @@ regmove_optimize (rtx f, int nregs) for (pass = 0; pass <= 2; pass++) { /* We need fewer optimizations for IRA. */ - if ((! flag_regmove || flag_ira) && pass >= flag_expensive_optimizations) + if (! flag_regmove && pass >= flag_expensive_optimizations) goto done; if (dump_file) @@ -1137,7 +1101,6 @@ regmove_optimize (rtx f, int nregs) insn = pass ? PREV_INSN (insn) : NEXT_INSN (insn)) { rtx set; - int op_no, match_no; set = single_set (insn); if (! set) @@ -1174,103 +1137,6 @@ regmove_optimize (rtx f, int nregs) } } } - - /* All optimizations important for IRA have been done. */ - if (! flag_regmove || flag_ira) - continue; - - 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_data.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_data.operand[op_no]; - dst = recog_data.operand[match_no]; - - if (!REG_P (src)) - continue; - - src_subreg = src; - if (GET_CODE (dst) == SUBREG - && GET_MODE_SIZE (GET_MODE (dst)) - >= GET_MODE_SIZE (GET_MODE (SUBREG_REG (dst)))) - { - dst = SUBREG_REG (dst); - src_subreg = lowpart_subreg (GET_MODE (dst), - src, GET_MODE (src)); - if (!src_subreg) - continue; - } - if (!REG_P (dst) - || 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, 0) > 1) - continue; - - /* Make sure match_operand is the destination. */ - if (recog_data.operand[match_no] != SET_DEST (set)) - continue; - - /* If the operands already match, then there is nothing to do. */ - if (operands_match_p (src, dst)) - continue; - - /* But in the commutative case, we might find a better match. */ - if (match.commutative[op_no] >= 0) - { - rtx comm = recog_data.operand[match.commutative[op_no]]; - if (operands_match_p (comm, dst) - && (replacement_quality (comm) - >= 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 (GET_MODE (src) != GET_MODE (dst)) - continue; - - if (fixup_match_1 (insn, set, src, src_subreg, dst, pass, - op_no, match_no)) - break; - } } } @@ -1656,478 +1522,6 @@ find_matches (rtx insn, struct match *matchp) return any_matches; } -/* Try to replace all occurrences of DST_REG with SRC in LOC, that is - assumed to be in INSN. */ - -static void -replace_in_call_usage (rtx *loc, unsigned int dst_reg, rtx src, rtx insn) -{ - rtx x = *loc; - enum rtx_code code; - const char *fmt; - int i, j; - - if (! x) - return; - - code = GET_CODE (x); - if (code == REG) - { - if (REGNO (x) != dst_reg) - return; - - validate_change (insn, loc, src, 1); - - return; - } - - /* Process each of our operands recursively. */ - fmt = GET_RTX_FORMAT (code); - for (i = 0; i < GET_RTX_LENGTH (code); i++, fmt++) - if (*fmt == 'e') - replace_in_call_usage (&XEXP (x, i), dst_reg, src, insn); - else if (*fmt == 'E') - for (j = 0; j < XVECLEN (x, i); j++) - replace_in_call_usage (& XVECEXP (x, i, j), dst_reg, src, insn); -} - -/* Try to replace output operand DST in SET, with input operand SRC. SET is - the only set in INSN. INSN has just been recognized 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 (rtx insn, rtx set, rtx src, rtx src_subreg, rtx dst, - int backward, int operand_number, int match_number) -{ - rtx p; - rtx post_inc = 0, post_inc_set = 0, search_end = 0; - int success = 0; - int num_calls = 0, freq_calls = 0, s_num_calls = 0, s_freq_calls = 0; - enum rtx_code code = NOTE; - HOST_WIDE_INT insn_const = 0, newconst = 0; - rtx overlap = 0; /* need to move insn ? */ - rtx src_note = find_reg_note (insn, REG_DEAD, src), dst_note = NULL_RTX; - int length, s_length; - - 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 (dump_file) - fprintf (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)) - 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 (CALL_P (p)) - replace_in_call_usage (& CALL_INSN_FUNCTION_USAGE (p), - REGNO (dst), src, p); - - /* ??? We can't scan past the end of a basic block without updating - the register lifetime info (REG_DEAD/basic_block_live_at_start). */ - if (perhaps_ends_bb_p (p)) - break; - else if (! INSN_P (p)) - 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 we would be moving INSN, check that we won't move it - into the shadow of a live a live flags register. */ - /* ??? We only try to move it in front of P, although - we could move it anywhere between OVERLAP and P. */ - if (overlap && GET_MODE (PREV_INSN (p)) != VOIDmode) - break; - - if (! src_note) - { - rtx q; - rtx set2 = NULL_RTX; - - /* 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)) - { - /* ??? We can't scan past the end of a basic block without - updating the register lifetime info - (REG_DEAD/basic_block_live_at_start). */ - if (perhaps_ends_bb_p (q)) - { - q = 0; - break; - } - else if (! INSN_P (q)) - continue; - else 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) - && REG_P (SET_DEST (single_set (p))) - && (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 - || ((unsigned HOST_WIDE_INT) 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_data.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 wrt. the registers that it - sets / uses when we found no REG_DEAD note for src on it, but it - still might clobber the flags register. We'll have to check that - we won't insert it into the shadow of a live flags register when - we finally know where we are to move 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 (CALL_P (p)) - { - if (REG_N_CALLS_CROSSED (REGNO (src)) == 0) - break; - - num_calls++; - freq_calls += REG_FREQ_FROM_BB (BLOCK_FOR_INSN (p)); - - if (src_note) - { - s_num_calls++; - s_freq_calls += REG_FREQ_FROM_BB (BLOCK_FOR_INSN (p)); - } - } - } - - if (! success) - return 0; - - /* 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); - INC_REG_N_SETS (REGNO (src), 1); - 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); - - p = emit_insn_after_setloc (pat, PREV_INSN (p), INSN_LOCATOR (insn)); - delete_insn (insn); - REG_NOTES (p) = notes; - df_notes_rescan (p); - } - } - /* 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 = NULL_RTX; - int num_calls2 = 0, s_length2 = 0, freq_calls2 = 0; - - if (note && CONSTANT_P (XEXP (note, 0))) - { - for (q = PREV_INSN (insn); q; q = PREV_INSN (q)) - { - /* ??? We can't scan past the end of a basic block without - updating the register lifetime info - (REG_DEAD/basic_block_live_at_start). */ - if (perhaps_ends_bb_p (q)) - { - q = 0; - break; - } - else if (! INSN_P (q)) - 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 (CALL_P (p)) - { - num_calls2++; - freq_calls2 += REG_FREQ_FROM_BB (BLOCK_FOR_INSN (p)); - } - } - if (q && set2 && SET_DEST (set2) == src && CONSTANT_P (SET_SRC (set2)) - && validate_change (insn, &SET_SRC (set), XEXP (note, 0), 0)) - { - delete_insn (q); - INC_REG_N_SETS (REGNO (src), -1); - REG_N_CALLS_CROSSED (REGNO (src)) -= num_calls2; - REG_FREQ_CALLS_CROSSED (REGNO (src)) -= freq_calls2; - 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)); ) - { - /* ??? We can't scan past the end of a basic block without updating - the register lifetime info - (REG_DEAD/basic_block_live_at_start). */ - if (perhaps_ends_bb_p (q)) - break; - else if (! INSN_P (q)) - continue; - else if (src != inc_dest - && (reg_overlap_mentioned_p (src, PATTERN (q)) - || reg_set_p (src, q))) - break; - else if (reg_set_p (inc_dest, q)) - break; - else 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_FREQ_CALLS_CROSSED (REGNO (src)) += s_freq_calls; - } - - INC_REG_N_SETS (REGNO (src), 1); - INC_REG_N_SETS (REGNO (dst), -1); - - REG_N_CALLS_CROSSED (REGNO (dst)) -= num_calls; - REG_FREQ_CALLS_CROSSED (REGNO (dst)) -= freq_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; - } - if (dump_file) - fprintf (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 registers 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. */ -static int -stable_and_no_regs_but_for_p (rtx x, rtx src, rtx dst) -{ - RTX_CODE code = GET_CODE (x); - switch (GET_RTX_CLASS (code)) - { - case RTX_UNARY: - case RTX_BIN_ARITH: - case RTX_COMM_ARITH: - case RTX_COMPARE: - case RTX_COMM_COMPARE: - case RTX_TERNARY: - case RTX_BITFIELD_OPS: - { - int i; - const 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 RTX_OBJ: - 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); - } -} static bool |