1 /* If-conversion support.
2 Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006
3 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it
8 under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2, or (at your option)
12 GCC is distributed in the hope that it will be useful, but WITHOUT
13 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
14 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
15 License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
24 #include "coretypes.h"
31 #include "insn-config.h"
34 #include "hard-reg-set.h"
35 #include "basic-block.h"
45 #include "tree-pass.h"
48 #ifndef HAVE_conditional_execution
49 #define HAVE_conditional_execution 0
51 #ifndef HAVE_conditional_move
52 #define HAVE_conditional_move 0
63 #ifndef HAVE_conditional_trap
64 #define HAVE_conditional_trap 0
67 #ifndef MAX_CONDITIONAL_EXECUTE
68 #define MAX_CONDITIONAL_EXECUTE (BRANCH_COST + 1)
71 #define NULL_BLOCK ((basic_block) NULL)
73 /* # of IF-THEN or IF-THEN-ELSE blocks we looked at */
74 static int num_possible_if_blocks;
76 /* # of IF-THEN or IF-THEN-ELSE blocks were converted to conditional
78 static int num_updated_if_blocks;
80 /* # of changes made which require life information to be updated. */
81 static int num_true_changes;
83 /* Whether conditional execution changes were made. */
84 static int cond_exec_changed_p;
86 /* True if life data ok at present. */
87 static bool life_data_ok;
89 /* Forward references. */
90 static int count_bb_insns (basic_block);
91 static bool cheap_bb_rtx_cost_p (basic_block, int);
92 static rtx first_active_insn (basic_block);
93 static rtx last_active_insn (basic_block, int);
94 static basic_block block_fallthru (basic_block);
95 static int cond_exec_process_insns (ce_if_block_t *, rtx, rtx, rtx, rtx, int);
96 static rtx cond_exec_get_condition (rtx);
97 static int cond_exec_process_if_block (ce_if_block_t *, int);
98 static rtx noce_get_condition (rtx, rtx *);
99 static int noce_operand_ok (rtx);
100 static int noce_process_if_block (ce_if_block_t *);
101 static int process_if_block (ce_if_block_t *);
102 static void merge_if_block (ce_if_block_t *);
103 static int find_cond_trap (basic_block, edge, edge);
104 static basic_block find_if_header (basic_block, int);
105 static int block_jumps_and_fallthru_p (basic_block, basic_block);
106 static int find_if_block (ce_if_block_t *);
107 static int find_if_case_1 (basic_block, edge, edge);
108 static int find_if_case_2 (basic_block, edge, edge);
109 static int find_memory (rtx *, void *);
110 static int dead_or_predicable (basic_block, basic_block, basic_block,
112 static void noce_emit_move_insn (rtx, rtx);
113 static rtx block_has_only_trap (basic_block);
115 /* Count the number of non-jump active insns in BB. */
118 count_bb_insns (basic_block bb)
121 rtx insn = BB_HEAD (bb);
125 if (CALL_P (insn) || NONJUMP_INSN_P (insn))
128 if (insn == BB_END (bb))
130 insn = NEXT_INSN (insn);
136 /* Determine whether the total insn_rtx_cost on non-jump insns in
137 basic block BB is less than MAX_COST. This function returns
138 false if the cost of any instruction could not be estimated. */
141 cheap_bb_rtx_cost_p (basic_block bb, int max_cost)
144 rtx insn = BB_HEAD (bb);
148 if (NONJUMP_INSN_P (insn))
150 int cost = insn_rtx_cost (PATTERN (insn));
154 /* If this instruction is the load or set of a "stack" register,
155 such as a floating point register on x87, then the cost of
156 speculatively executing this insn may need to include
157 the additional cost of popping its result off of the
158 register stack. Unfortunately, correctly recognizing and
159 accounting for this additional overhead is tricky, so for
160 now we simply prohibit such speculative execution. */
163 rtx set = single_set (insn);
164 if (set && STACK_REG_P (SET_DEST (set)))
170 if (count >= max_cost)
173 else if (CALL_P (insn))
176 if (insn == BB_END (bb))
178 insn = NEXT_INSN (insn);
184 /* Return the first non-jump active insn in the basic block. */
187 first_active_insn (basic_block bb)
189 rtx insn = BB_HEAD (bb);
193 if (insn == BB_END (bb))
195 insn = NEXT_INSN (insn);
198 while (NOTE_P (insn))
200 if (insn == BB_END (bb))
202 insn = NEXT_INSN (insn);
211 /* Return the last non-jump active (non-jump) insn in the basic block. */
214 last_active_insn (basic_block bb, int skip_use_p)
216 rtx insn = BB_END (bb);
217 rtx head = BB_HEAD (bb);
222 && NONJUMP_INSN_P (insn)
223 && GET_CODE (PATTERN (insn)) == USE))
227 insn = PREV_INSN (insn);
236 /* Return the basic block reached by falling though the basic block BB. */
239 block_fallthru (basic_block bb)
244 FOR_EACH_EDGE (e, ei, bb->succs)
245 if (e->flags & EDGE_FALLTHRU)
248 return (e) ? e->dest : NULL_BLOCK;
251 /* Go through a bunch of insns, converting them to conditional
252 execution format if possible. Return TRUE if all of the non-note
253 insns were processed. */
256 cond_exec_process_insns (ce_if_block_t *ce_info ATTRIBUTE_UNUSED,
257 /* if block information */rtx start,
258 /* first insn to look at */rtx end,
259 /* last insn to look at */rtx test,
260 /* conditional execution test */rtx prob_val,
261 /* probability of branch taken. */int mod_ok)
263 int must_be_last = FALSE;
271 for (insn = start; ; insn = NEXT_INSN (insn))
276 gcc_assert(NONJUMP_INSN_P (insn) || CALL_P (insn));
278 /* Remove USE insns that get in the way. */
279 if (reload_completed && GET_CODE (PATTERN (insn)) == USE)
281 /* ??? Ug. Actually unlinking the thing is problematic,
282 given what we'd have to coordinate with our callers. */
283 SET_INSN_DELETED (insn);
287 /* Last insn wasn't last? */
291 if (modified_in_p (test, insn))
298 /* Now build the conditional form of the instruction. */
299 pattern = PATTERN (insn);
300 xtest = copy_rtx (test);
302 /* If this is already a COND_EXEC, rewrite the test to be an AND of the
304 if (GET_CODE (pattern) == COND_EXEC)
306 if (GET_MODE (xtest) != GET_MODE (COND_EXEC_TEST (pattern)))
309 xtest = gen_rtx_AND (GET_MODE (xtest), xtest,
310 COND_EXEC_TEST (pattern));
311 pattern = COND_EXEC_CODE (pattern);
314 pattern = gen_rtx_COND_EXEC (VOIDmode, xtest, pattern);
316 /* If the machine needs to modify the insn being conditionally executed,
317 say for example to force a constant integer operand into a temp
318 register, do so here. */
319 #ifdef IFCVT_MODIFY_INSN
320 IFCVT_MODIFY_INSN (ce_info, pattern, insn);
325 validate_change (insn, &PATTERN (insn), pattern, 1);
327 if (CALL_P (insn) && prob_val)
328 validate_change (insn, ®_NOTES (insn),
329 alloc_EXPR_LIST (REG_BR_PROB, prob_val,
330 REG_NOTES (insn)), 1);
340 /* Return the condition for a jump. Do not do any special processing. */
343 cond_exec_get_condition (rtx jump)
347 if (any_condjump_p (jump))
348 test_if = SET_SRC (pc_set (jump));
351 cond = XEXP (test_if, 0);
353 /* If this branches to JUMP_LABEL when the condition is false,
354 reverse the condition. */
355 if (GET_CODE (XEXP (test_if, 2)) == LABEL_REF
356 && XEXP (XEXP (test_if, 2), 0) == JUMP_LABEL (jump))
358 enum rtx_code rev = reversed_comparison_code (cond, jump);
362 cond = gen_rtx_fmt_ee (rev, GET_MODE (cond), XEXP (cond, 0),
369 /* Given a simple IF-THEN or IF-THEN-ELSE block, attempt to convert it
370 to conditional execution. Return TRUE if we were successful at
371 converting the block. */
374 cond_exec_process_if_block (ce_if_block_t * ce_info,
375 /* if block information */int do_multiple_p)
377 basic_block test_bb = ce_info->test_bb; /* last test block */
378 basic_block then_bb = ce_info->then_bb; /* THEN */
379 basic_block else_bb = ce_info->else_bb; /* ELSE or NULL */
380 rtx test_expr; /* expression in IF_THEN_ELSE that is tested */
381 rtx then_start; /* first insn in THEN block */
382 rtx then_end; /* last insn + 1 in THEN block */
383 rtx else_start = NULL_RTX; /* first insn in ELSE block or NULL */
384 rtx else_end = NULL_RTX; /* last insn + 1 in ELSE block */
385 int max; /* max # of insns to convert. */
386 int then_mod_ok; /* whether conditional mods are ok in THEN */
387 rtx true_expr; /* test for else block insns */
388 rtx false_expr; /* test for then block insns */
389 rtx true_prob_val; /* probability of else block */
390 rtx false_prob_val; /* probability of then block */
392 enum rtx_code false_code;
394 /* If test is comprised of && or || elements, and we've failed at handling
395 all of them together, just use the last test if it is the special case of
396 && elements without an ELSE block. */
397 if (!do_multiple_p && ce_info->num_multiple_test_blocks)
399 if (else_bb || ! ce_info->and_and_p)
402 ce_info->test_bb = test_bb = ce_info->last_test_bb;
403 ce_info->num_multiple_test_blocks = 0;
404 ce_info->num_and_and_blocks = 0;
405 ce_info->num_or_or_blocks = 0;
408 /* Find the conditional jump to the ELSE or JOIN part, and isolate
410 test_expr = cond_exec_get_condition (BB_END (test_bb));
414 /* If the conditional jump is more than just a conditional jump,
415 then we can not do conditional execution conversion on this block. */
416 if (! onlyjump_p (BB_END (test_bb)))
419 /* Collect the bounds of where we're to search, skipping any labels, jumps
420 and notes at the beginning and end of the block. Then count the total
421 number of insns and see if it is small enough to convert. */
422 then_start = first_active_insn (then_bb);
423 then_end = last_active_insn (then_bb, TRUE);
424 n_insns = ce_info->num_then_insns = count_bb_insns (then_bb);
425 max = MAX_CONDITIONAL_EXECUTE;
430 else_start = first_active_insn (else_bb);
431 else_end = last_active_insn (else_bb, TRUE);
432 n_insns += ce_info->num_else_insns = count_bb_insns (else_bb);
438 /* Map test_expr/test_jump into the appropriate MD tests to use on
439 the conditionally executed code. */
441 true_expr = test_expr;
443 false_code = reversed_comparison_code (true_expr, BB_END (test_bb));
444 if (false_code != UNKNOWN)
445 false_expr = gen_rtx_fmt_ee (false_code, GET_MODE (true_expr),
446 XEXP (true_expr, 0), XEXP (true_expr, 1));
448 false_expr = NULL_RTX;
450 #ifdef IFCVT_MODIFY_TESTS
451 /* If the machine description needs to modify the tests, such as setting a
452 conditional execution register from a comparison, it can do so here. */
453 IFCVT_MODIFY_TESTS (ce_info, true_expr, false_expr);
455 /* See if the conversion failed. */
456 if (!true_expr || !false_expr)
460 true_prob_val = find_reg_note (BB_END (test_bb), REG_BR_PROB, NULL_RTX);
463 true_prob_val = XEXP (true_prob_val, 0);
464 false_prob_val = GEN_INT (REG_BR_PROB_BASE - INTVAL (true_prob_val));
467 false_prob_val = NULL_RTX;
469 /* If we have && or || tests, do them here. These tests are in the adjacent
470 blocks after the first block containing the test. */
471 if (ce_info->num_multiple_test_blocks > 0)
473 basic_block bb = test_bb;
474 basic_block last_test_bb = ce_info->last_test_bb;
483 enum rtx_code f_code;
485 bb = block_fallthru (bb);
486 start = first_active_insn (bb);
487 end = last_active_insn (bb, TRUE);
489 && ! cond_exec_process_insns (ce_info, start, end, false_expr,
490 false_prob_val, FALSE))
493 /* If the conditional jump is more than just a conditional jump, then
494 we can not do conditional execution conversion on this block. */
495 if (! onlyjump_p (BB_END (bb)))
498 /* Find the conditional jump and isolate the test. */
499 t = cond_exec_get_condition (BB_END (bb));
503 f_code = reversed_comparison_code (t, BB_END (bb));
504 if (f_code == UNKNOWN)
507 f = gen_rtx_fmt_ee (f_code, GET_MODE (t), XEXP (t, 0), XEXP (t, 1));
508 if (ce_info->and_and_p)
510 t = gen_rtx_AND (GET_MODE (t), true_expr, t);
511 f = gen_rtx_IOR (GET_MODE (t), false_expr, f);
515 t = gen_rtx_IOR (GET_MODE (t), true_expr, t);
516 f = gen_rtx_AND (GET_MODE (t), false_expr, f);
519 /* If the machine description needs to modify the tests, such as
520 setting a conditional execution register from a comparison, it can
522 #ifdef IFCVT_MODIFY_MULTIPLE_TESTS
523 IFCVT_MODIFY_MULTIPLE_TESTS (ce_info, bb, t, f);
525 /* See if the conversion failed. */
533 while (bb != last_test_bb);
536 /* For IF-THEN-ELSE blocks, we don't allow modifications of the test
537 on then THEN block. */
538 then_mod_ok = (else_bb == NULL_BLOCK);
540 /* Go through the THEN and ELSE blocks converting the insns if possible
541 to conditional execution. */
545 || ! cond_exec_process_insns (ce_info, then_start, then_end,
546 false_expr, false_prob_val,
550 if (else_bb && else_end
551 && ! cond_exec_process_insns (ce_info, else_start, else_end,
552 true_expr, true_prob_val, TRUE))
555 /* If we cannot apply the changes, fail. Do not go through the normal fail
556 processing, since apply_change_group will call cancel_changes. */
557 if (! apply_change_group ())
559 #ifdef IFCVT_MODIFY_CANCEL
560 /* Cancel any machine dependent changes. */
561 IFCVT_MODIFY_CANCEL (ce_info);
566 #ifdef IFCVT_MODIFY_FINAL
567 /* Do any machine dependent final modifications. */
568 IFCVT_MODIFY_FINAL (ce_info);
571 /* Conversion succeeded. */
573 fprintf (dump_file, "%d insn%s converted to conditional execution.\n",
574 n_insns, (n_insns == 1) ? " was" : "s were");
576 /* Merge the blocks! */
577 merge_if_block (ce_info);
578 cond_exec_changed_p = TRUE;
582 #ifdef IFCVT_MODIFY_CANCEL
583 /* Cancel any machine dependent changes. */
584 IFCVT_MODIFY_CANCEL (ce_info);
591 /* Used by noce_process_if_block to communicate with its subroutines.
593 The subroutines know that A and B may be evaluated freely. They
594 know that X is a register. They should insert new instructions
595 before cond_earliest. */
602 rtx jump, cond, cond_earliest;
603 /* True if "b" was originally evaluated unconditionally. */
604 bool b_unconditional;
607 static rtx noce_emit_store_flag (struct noce_if_info *, rtx, int, int);
608 static int noce_try_move (struct noce_if_info *);
609 static int noce_try_store_flag (struct noce_if_info *);
610 static int noce_try_addcc (struct noce_if_info *);
611 static int noce_try_store_flag_constants (struct noce_if_info *);
612 static int noce_try_store_flag_mask (struct noce_if_info *);
613 static rtx noce_emit_cmove (struct noce_if_info *, rtx, enum rtx_code, rtx,
615 static int noce_try_cmove (struct noce_if_info *);
616 static int noce_try_cmove_arith (struct noce_if_info *);
617 static rtx noce_get_alt_condition (struct noce_if_info *, rtx, rtx *);
618 static int noce_try_minmax (struct noce_if_info *);
619 static int noce_try_abs (struct noce_if_info *);
620 static int noce_try_sign_mask (struct noce_if_info *);
622 /* Helper function for noce_try_store_flag*. */
625 noce_emit_store_flag (struct noce_if_info *if_info, rtx x, int reversep,
628 rtx cond = if_info->cond;
632 cond_complex = (! general_operand (XEXP (cond, 0), VOIDmode)
633 || ! general_operand (XEXP (cond, 1), VOIDmode));
635 /* If earliest == jump, or when the condition is complex, try to
636 build the store_flag insn directly. */
639 cond = XEXP (SET_SRC (pc_set (if_info->jump)), 0);
642 code = reversed_comparison_code (cond, if_info->jump);
644 code = GET_CODE (cond);
646 if ((if_info->cond_earliest == if_info->jump || cond_complex)
647 && (normalize == 0 || STORE_FLAG_VALUE == normalize))
651 tmp = gen_rtx_fmt_ee (code, GET_MODE (x), XEXP (cond, 0),
653 tmp = gen_rtx_SET (VOIDmode, x, tmp);
656 tmp = emit_insn (tmp);
658 if (recog_memoized (tmp) >= 0)
664 if_info->cond_earliest = if_info->jump;
672 /* Don't even try if the comparison operands or the mode of X are weird. */
673 if (cond_complex || !SCALAR_INT_MODE_P (GET_MODE (x)))
676 return emit_store_flag (x, code, XEXP (cond, 0),
677 XEXP (cond, 1), VOIDmode,
678 (code == LTU || code == LEU
679 || code == GEU || code == GTU), normalize);
682 /* Emit instruction to move an rtx, possibly into STRICT_LOW_PART.
683 X is the destination/target and Y is the value to copy. */
686 noce_emit_move_insn (rtx x, rtx y)
688 enum machine_mode outmode;
692 if (GET_CODE (x) != STRICT_LOW_PART)
694 rtx seq, insn, target;
698 /* Check that the SET_SRC is reasonable before calling emit_move_insn,
699 otherwise construct a suitable SET pattern ourselves. */
700 insn = (OBJECT_P (y) || CONSTANT_P (y) || GET_CODE (y) == SUBREG)
701 ? emit_move_insn (x, y)
702 : emit_insn (gen_rtx_SET (VOIDmode, x, y));
706 if (recog_memoized (insn) <= 0)
708 if (GET_CODE (x) == ZERO_EXTRACT)
710 rtx op = XEXP (x, 0);
711 unsigned HOST_WIDE_INT size = INTVAL (XEXP (x, 1));
712 unsigned HOST_WIDE_INT start = INTVAL (XEXP (x, 2));
714 /* store_bit_field expects START to be relative to
715 BYTES_BIG_ENDIAN and adjusts this value for machines with
716 BITS_BIG_ENDIAN != BYTES_BIG_ENDIAN. In order to be able to
717 invoke store_bit_field again it is necessary to have the START
718 value from the first call. */
719 if (BITS_BIG_ENDIAN != BYTES_BIG_ENDIAN)
722 start = BITS_PER_UNIT - start - size;
725 gcc_assert (REG_P (op));
726 start = BITS_PER_WORD - start - size;
730 gcc_assert (start < (MEM_P (op) ? BITS_PER_UNIT : BITS_PER_WORD));
731 store_bit_field (op, size, start, GET_MODE (x), y);
735 switch (GET_RTX_CLASS (GET_CODE (y)))
738 ot = code_to_optab[GET_CODE (y)];
742 target = expand_unop (GET_MODE (y), ot, XEXP (y, 0), x, 0);
743 if (target != NULL_RTX)
746 emit_move_insn (x, target);
755 ot = code_to_optab[GET_CODE (y)];
759 target = expand_binop (GET_MODE (y), ot,
760 XEXP (y, 0), XEXP (y, 1),
762 if (target != NULL_RTX)
765 emit_move_insn (x, target);
782 inner = XEXP (outer, 0);
783 outmode = GET_MODE (outer);
784 bitpos = SUBREG_BYTE (outer) * BITS_PER_UNIT;
785 store_bit_field (inner, GET_MODE_BITSIZE (outmode), bitpos, outmode, y);
788 /* Return sequence of instructions generated by if conversion. This
789 function calls end_sequence() to end the current stream, ensures
790 that are instructions are unshared, recognizable non-jump insns.
791 On failure, this function returns a NULL_RTX. */
794 end_ifcvt_sequence (struct noce_if_info *if_info)
797 rtx seq = get_insns ();
799 set_used_flags (if_info->x);
800 set_used_flags (if_info->cond);
801 unshare_all_rtl_in_chain (seq);
804 /* Make sure that all of the instructions emitted are recognizable,
805 and that we haven't introduced a new jump instruction.
806 As an exercise for the reader, build a general mechanism that
807 allows proper placement of required clobbers. */
808 for (insn = seq; insn; insn = NEXT_INSN (insn))
810 || recog_memoized (insn) == -1)
816 /* Convert "if (a != b) x = a; else x = b" into "x = a" and
817 "if (a == b) x = a; else x = b" into "x = b". */
820 noce_try_move (struct noce_if_info *if_info)
822 rtx cond = if_info->cond;
823 enum rtx_code code = GET_CODE (cond);
826 if (code != NE && code != EQ)
829 /* This optimization isn't valid if either A or B could be a NaN
831 if (HONOR_NANS (GET_MODE (if_info->x))
832 || HONOR_SIGNED_ZEROS (GET_MODE (if_info->x)))
835 /* Check whether the operands of the comparison are A and in
837 if ((rtx_equal_p (if_info->a, XEXP (cond, 0))
838 && rtx_equal_p (if_info->b, XEXP (cond, 1)))
839 || (rtx_equal_p (if_info->a, XEXP (cond, 1))
840 && rtx_equal_p (if_info->b, XEXP (cond, 0))))
842 y = (code == EQ) ? if_info->a : if_info->b;
844 /* Avoid generating the move if the source is the destination. */
845 if (! rtx_equal_p (if_info->x, y))
848 noce_emit_move_insn (if_info->x, y);
849 seq = end_ifcvt_sequence (if_info);
853 emit_insn_before_setloc (seq, if_info->jump,
854 INSN_LOCATOR (if_info->insn_a));
861 /* Convert "if (test) x = 1; else x = 0".
863 Only try 0 and STORE_FLAG_VALUE here. Other combinations will be
864 tried in noce_try_store_flag_constants after noce_try_cmove has had
865 a go at the conversion. */
868 noce_try_store_flag (struct noce_if_info *if_info)
873 if (GET_CODE (if_info->b) == CONST_INT
874 && INTVAL (if_info->b) == STORE_FLAG_VALUE
875 && if_info->a == const0_rtx)
877 else if (if_info->b == const0_rtx
878 && GET_CODE (if_info->a) == CONST_INT
879 && INTVAL (if_info->a) == STORE_FLAG_VALUE
880 && (reversed_comparison_code (if_info->cond, if_info->jump)
888 target = noce_emit_store_flag (if_info, if_info->x, reversep, 0);
891 if (target != if_info->x)
892 noce_emit_move_insn (if_info->x, target);
894 seq = end_ifcvt_sequence (if_info);
898 emit_insn_before_setloc (seq, if_info->jump,
899 INSN_LOCATOR (if_info->insn_a));
909 /* Convert "if (test) x = a; else x = b", for A and B constant. */
912 noce_try_store_flag_constants (struct noce_if_info *if_info)
916 HOST_WIDE_INT itrue, ifalse, diff, tmp;
917 int normalize, can_reverse;
918 enum machine_mode mode;
921 && GET_CODE (if_info->a) == CONST_INT
922 && GET_CODE (if_info->b) == CONST_INT)
924 mode = GET_MODE (if_info->x);
925 ifalse = INTVAL (if_info->a);
926 itrue = INTVAL (if_info->b);
928 /* Make sure we can represent the difference between the two values. */
929 if ((itrue - ifalse > 0)
930 != ((ifalse < 0) != (itrue < 0) ? ifalse < 0 : ifalse < itrue))
933 diff = trunc_int_for_mode (itrue - ifalse, mode);
935 can_reverse = (reversed_comparison_code (if_info->cond, if_info->jump)
939 if (diff == STORE_FLAG_VALUE || diff == -STORE_FLAG_VALUE)
941 else if (ifalse == 0 && exact_log2 (itrue) >= 0
942 && (STORE_FLAG_VALUE == 1
943 || BRANCH_COST >= 2))
945 else if (itrue == 0 && exact_log2 (ifalse) >= 0 && can_reverse
946 && (STORE_FLAG_VALUE == 1 || BRANCH_COST >= 2))
947 normalize = 1, reversep = 1;
949 && (STORE_FLAG_VALUE == -1
950 || BRANCH_COST >= 2))
952 else if (ifalse == -1 && can_reverse
953 && (STORE_FLAG_VALUE == -1 || BRANCH_COST >= 2))
954 normalize = -1, reversep = 1;
955 else if ((BRANCH_COST >= 2 && STORE_FLAG_VALUE == -1)
963 tmp = itrue; itrue = ifalse; ifalse = tmp;
964 diff = trunc_int_for_mode (-diff, mode);
968 target = noce_emit_store_flag (if_info, if_info->x, reversep, normalize);
975 /* if (test) x = 3; else x = 4;
976 => x = 3 + (test == 0); */
977 if (diff == STORE_FLAG_VALUE || diff == -STORE_FLAG_VALUE)
979 target = expand_simple_binop (mode,
980 (diff == STORE_FLAG_VALUE
982 GEN_INT (ifalse), target, if_info->x, 0,
986 /* if (test) x = 8; else x = 0;
987 => x = (test != 0) << 3; */
988 else if (ifalse == 0 && (tmp = exact_log2 (itrue)) >= 0)
990 target = expand_simple_binop (mode, ASHIFT,
991 target, GEN_INT (tmp), if_info->x, 0,
995 /* if (test) x = -1; else x = b;
996 => x = -(test != 0) | b; */
997 else if (itrue == -1)
999 target = expand_simple_binop (mode, IOR,
1000 target, GEN_INT (ifalse), if_info->x, 0,
1004 /* if (test) x = a; else x = b;
1005 => x = (-(test != 0) & (b - a)) + a; */
1008 target = expand_simple_binop (mode, AND,
1009 target, GEN_INT (diff), if_info->x, 0,
1012 target = expand_simple_binop (mode, PLUS,
1013 target, GEN_INT (ifalse),
1014 if_info->x, 0, OPTAB_WIDEN);
1023 if (target != if_info->x)
1024 noce_emit_move_insn (if_info->x, target);
1026 seq = end_ifcvt_sequence (if_info);
1030 emit_insn_before_setloc (seq, if_info->jump,
1031 INSN_LOCATOR (if_info->insn_a));
1038 /* Convert "if (test) foo++" into "foo += (test != 0)", and
1039 similarly for "foo--". */
1042 noce_try_addcc (struct noce_if_info *if_info)
1045 int subtract, normalize;
1047 if (! no_new_pseudos
1048 && GET_CODE (if_info->a) == PLUS
1049 && rtx_equal_p (XEXP (if_info->a, 0), if_info->b)
1050 && (reversed_comparison_code (if_info->cond, if_info->jump)
1053 rtx cond = if_info->cond;
1054 enum rtx_code code = reversed_comparison_code (cond, if_info->jump);
1056 /* First try to use addcc pattern. */
1057 if (general_operand (XEXP (cond, 0), VOIDmode)
1058 && general_operand (XEXP (cond, 1), VOIDmode))
1061 target = emit_conditional_add (if_info->x, code,
1066 XEXP (if_info->a, 1),
1067 GET_MODE (if_info->x),
1068 (code == LTU || code == GEU
1069 || code == LEU || code == GTU));
1072 if (target != if_info->x)
1073 noce_emit_move_insn (if_info->x, target);
1075 seq = end_ifcvt_sequence (if_info);
1079 emit_insn_before_setloc (seq, if_info->jump,
1080 INSN_LOCATOR (if_info->insn_a));
1086 /* If that fails, construct conditional increment or decrement using
1088 if (BRANCH_COST >= 2
1089 && (XEXP (if_info->a, 1) == const1_rtx
1090 || XEXP (if_info->a, 1) == constm1_rtx))
1093 if (STORE_FLAG_VALUE == INTVAL (XEXP (if_info->a, 1)))
1094 subtract = 0, normalize = 0;
1095 else if (-STORE_FLAG_VALUE == INTVAL (XEXP (if_info->a, 1)))
1096 subtract = 1, normalize = 0;
1098 subtract = 0, normalize = INTVAL (XEXP (if_info->a, 1));
1101 target = noce_emit_store_flag (if_info,
1102 gen_reg_rtx (GET_MODE (if_info->x)),
1106 target = expand_simple_binop (GET_MODE (if_info->x),
1107 subtract ? MINUS : PLUS,
1108 if_info->b, target, if_info->x,
1112 if (target != if_info->x)
1113 noce_emit_move_insn (if_info->x, target);
1115 seq = end_ifcvt_sequence (if_info);
1119 emit_insn_before_setloc (seq, if_info->jump,
1120 INSN_LOCATOR (if_info->insn_a));
1130 /* Convert "if (test) x = 0;" to "x &= -(test == 0);" */
1133 noce_try_store_flag_mask (struct noce_if_info *if_info)
1139 if (! no_new_pseudos
1140 && (BRANCH_COST >= 2
1141 || STORE_FLAG_VALUE == -1)
1142 && ((if_info->a == const0_rtx
1143 && rtx_equal_p (if_info->b, if_info->x))
1144 || ((reversep = (reversed_comparison_code (if_info->cond,
1147 && if_info->b == const0_rtx
1148 && rtx_equal_p (if_info->a, if_info->x))))
1151 target = noce_emit_store_flag (if_info,
1152 gen_reg_rtx (GET_MODE (if_info->x)),
1155 target = expand_simple_binop (GET_MODE (if_info->x), AND,
1157 target, if_info->x, 0,
1162 if (target != if_info->x)
1163 noce_emit_move_insn (if_info->x, target);
1165 seq = end_ifcvt_sequence (if_info);
1169 emit_insn_before_setloc (seq, if_info->jump,
1170 INSN_LOCATOR (if_info->insn_a));
1180 /* Helper function for noce_try_cmove and noce_try_cmove_arith. */
1183 noce_emit_cmove (struct noce_if_info *if_info, rtx x, enum rtx_code code,
1184 rtx cmp_a, rtx cmp_b, rtx vfalse, rtx vtrue)
1186 /* If earliest == jump, try to build the cmove insn directly.
1187 This is helpful when combine has created some complex condition
1188 (like for alpha's cmovlbs) that we can't hope to regenerate
1189 through the normal interface. */
1191 if (if_info->cond_earliest == if_info->jump)
1195 tmp = gen_rtx_fmt_ee (code, GET_MODE (if_info->cond), cmp_a, cmp_b);
1196 tmp = gen_rtx_IF_THEN_ELSE (GET_MODE (x), tmp, vtrue, vfalse);
1197 tmp = gen_rtx_SET (VOIDmode, x, tmp);
1200 tmp = emit_insn (tmp);
1202 if (recog_memoized (tmp) >= 0)
1214 /* Don't even try if the comparison operands are weird. */
1215 if (! general_operand (cmp_a, GET_MODE (cmp_a))
1216 || ! general_operand (cmp_b, GET_MODE (cmp_b)))
1219 #if HAVE_conditional_move
1220 return emit_conditional_move (x, code, cmp_a, cmp_b, VOIDmode,
1221 vtrue, vfalse, GET_MODE (x),
1222 (code == LTU || code == GEU
1223 || code == LEU || code == GTU));
1225 /* We'll never get here, as noce_process_if_block doesn't call the
1226 functions involved. Ifdef code, however, should be discouraged
1227 because it leads to typos in the code not selected. However,
1228 emit_conditional_move won't exist either. */
1233 /* Try only simple constants and registers here. More complex cases
1234 are handled in noce_try_cmove_arith after noce_try_store_flag_arith
1235 has had a go at it. */
1238 noce_try_cmove (struct noce_if_info *if_info)
1243 if ((CONSTANT_P (if_info->a) || register_operand (if_info->a, VOIDmode))
1244 && (CONSTANT_P (if_info->b) || register_operand (if_info->b, VOIDmode)))
1248 code = GET_CODE (if_info->cond);
1249 target = noce_emit_cmove (if_info, if_info->x, code,
1250 XEXP (if_info->cond, 0),
1251 XEXP (if_info->cond, 1),
1252 if_info->a, if_info->b);
1256 if (target != if_info->x)
1257 noce_emit_move_insn (if_info->x, target);
1259 seq = end_ifcvt_sequence (if_info);
1263 emit_insn_before_setloc (seq, if_info->jump,
1264 INSN_LOCATOR (if_info->insn_a));
1277 /* Try more complex cases involving conditional_move. */
1280 noce_try_cmove_arith (struct noce_if_info *if_info)
1292 /* A conditional move from two memory sources is equivalent to a
1293 conditional on their addresses followed by a load. Don't do this
1294 early because it'll screw alias analysis. Note that we've
1295 already checked for no side effects. */
1296 if (! no_new_pseudos && cse_not_expected
1297 && MEM_P (a) && MEM_P (b)
1298 && BRANCH_COST >= 5)
1302 x = gen_reg_rtx (Pmode);
1306 /* ??? We could handle this if we knew that a load from A or B could
1307 not fault. This is also true if we've already loaded
1308 from the address along the path from ENTRY. */
1309 else if (may_trap_p (a) || may_trap_p (b))
1312 /* if (test) x = a + b; else x = c - d;
1319 code = GET_CODE (if_info->cond);
1320 insn_a = if_info->insn_a;
1321 insn_b = if_info->insn_b;
1323 /* Total insn_rtx_cost should be smaller than branch cost. Exit
1324 if insn_rtx_cost can't be estimated. */
1327 insn_cost = insn_rtx_cost (PATTERN (insn_a));
1328 if (insn_cost == 0 || insn_cost > COSTS_N_INSNS (BRANCH_COST))
1337 insn_cost += insn_rtx_cost (PATTERN (insn_b));
1338 if (insn_cost == 0 || insn_cost > COSTS_N_INSNS (BRANCH_COST))
1342 /* Possibly rearrange operands to make things come out more natural. */
1343 if (reversed_comparison_code (if_info->cond, if_info->jump) != UNKNOWN)
1346 if (rtx_equal_p (b, x))
1348 else if (general_operand (b, GET_MODE (b)))
1353 code = reversed_comparison_code (if_info->cond, if_info->jump);
1354 tmp = a, a = b, b = tmp;
1355 tmp = insn_a, insn_a = insn_b, insn_b = tmp;
1364 /* If either operand is complex, load it into a register first.
1365 The best way to do this is to copy the original insn. In this
1366 way we preserve any clobbers etc that the insn may have had.
1367 This is of course not possible in the IS_MEM case. */
1368 if (! general_operand (a, GET_MODE (a)))
1373 goto end_seq_and_fail;
1377 tmp = gen_reg_rtx (GET_MODE (a));
1378 tmp = emit_insn (gen_rtx_SET (VOIDmode, tmp, a));
1381 goto end_seq_and_fail;
1384 a = gen_reg_rtx (GET_MODE (a));
1385 tmp = copy_rtx (insn_a);
1386 set = single_set (tmp);
1388 tmp = emit_insn (PATTERN (tmp));
1390 if (recog_memoized (tmp) < 0)
1391 goto end_seq_and_fail;
1393 if (! general_operand (b, GET_MODE (b)))
1398 goto end_seq_and_fail;
1402 tmp = gen_reg_rtx (GET_MODE (b));
1403 tmp = gen_rtx_SET (VOIDmode, tmp, b);
1406 goto end_seq_and_fail;
1409 b = gen_reg_rtx (GET_MODE (b));
1410 tmp = copy_rtx (insn_b);
1411 set = single_set (tmp);
1413 tmp = PATTERN (tmp);
1416 /* If insn to set up A clobbers any registers B depends on, try to
1417 swap insn that sets up A with the one that sets up B. If even
1418 that doesn't help, punt. */
1419 last = get_last_insn ();
1420 if (last && modified_in_p (orig_b, last))
1422 tmp = emit_insn_before (tmp, get_insns ());
1423 if (modified_in_p (orig_a, tmp))
1424 goto end_seq_and_fail;
1427 tmp = emit_insn (tmp);
1429 if (recog_memoized (tmp) < 0)
1430 goto end_seq_and_fail;
1433 target = noce_emit_cmove (if_info, x, code, XEXP (if_info->cond, 0),
1434 XEXP (if_info->cond, 1), a, b);
1437 goto end_seq_and_fail;
1439 /* If we're handling a memory for above, emit the load now. */
1442 tmp = gen_rtx_MEM (GET_MODE (if_info->x), target);
1444 /* Copy over flags as appropriate. */
1445 if (MEM_VOLATILE_P (if_info->a) || MEM_VOLATILE_P (if_info->b))
1446 MEM_VOLATILE_P (tmp) = 1;
1447 if (MEM_IN_STRUCT_P (if_info->a) && MEM_IN_STRUCT_P (if_info->b))
1448 MEM_IN_STRUCT_P (tmp) = 1;
1449 if (MEM_SCALAR_P (if_info->a) && MEM_SCALAR_P (if_info->b))
1450 MEM_SCALAR_P (tmp) = 1;
1451 if (MEM_ALIAS_SET (if_info->a) == MEM_ALIAS_SET (if_info->b))
1452 set_mem_alias_set (tmp, MEM_ALIAS_SET (if_info->a));
1454 MIN (MEM_ALIGN (if_info->a), MEM_ALIGN (if_info->b)));
1456 noce_emit_move_insn (if_info->x, tmp);
1458 else if (target != x)
1459 noce_emit_move_insn (x, target);
1461 tmp = end_ifcvt_sequence (if_info);
1465 emit_insn_before_setloc (tmp, if_info->jump, INSN_LOCATOR (if_info->insn_a));
1473 /* For most cases, the simplified condition we found is the best
1474 choice, but this is not the case for the min/max/abs transforms.
1475 For these we wish to know that it is A or B in the condition. */
1478 noce_get_alt_condition (struct noce_if_info *if_info, rtx target,
1481 rtx cond, set, insn;
1484 /* If target is already mentioned in the known condition, return it. */
1485 if (reg_mentioned_p (target, if_info->cond))
1487 *earliest = if_info->cond_earliest;
1488 return if_info->cond;
1491 set = pc_set (if_info->jump);
1492 cond = XEXP (SET_SRC (set), 0);
1494 = GET_CODE (XEXP (SET_SRC (set), 2)) == LABEL_REF
1495 && XEXP (XEXP (SET_SRC (set), 2), 0) == JUMP_LABEL (if_info->jump);
1497 /* If we're looking for a constant, try to make the conditional
1498 have that constant in it. There are two reasons why it may
1499 not have the constant we want:
1501 1. GCC may have needed to put the constant in a register, because
1502 the target can't compare directly against that constant. For
1503 this case, we look for a SET immediately before the comparison
1504 that puts a constant in that register.
1506 2. GCC may have canonicalized the conditional, for example
1507 replacing "if x < 4" with "if x <= 3". We can undo that (or
1508 make equivalent types of changes) to get the constants we need
1509 if they're off by one in the right direction. */
1511 if (GET_CODE (target) == CONST_INT)
1513 enum rtx_code code = GET_CODE (if_info->cond);
1514 rtx op_a = XEXP (if_info->cond, 0);
1515 rtx op_b = XEXP (if_info->cond, 1);
1518 /* First, look to see if we put a constant in a register. */
1519 prev_insn = prev_nonnote_insn (if_info->cond_earliest);
1521 && INSN_P (prev_insn)
1522 && GET_CODE (PATTERN (prev_insn)) == SET)
1524 rtx src = find_reg_equal_equiv_note (prev_insn);
1526 src = SET_SRC (PATTERN (prev_insn));
1527 if (GET_CODE (src) == CONST_INT)
1529 if (rtx_equal_p (op_a, SET_DEST (PATTERN (prev_insn))))
1531 else if (rtx_equal_p (op_b, SET_DEST (PATTERN (prev_insn))))
1534 if (GET_CODE (op_a) == CONST_INT)
1539 code = swap_condition (code);
1544 /* Now, look to see if we can get the right constant by
1545 adjusting the conditional. */
1546 if (GET_CODE (op_b) == CONST_INT)
1548 HOST_WIDE_INT desired_val = INTVAL (target);
1549 HOST_WIDE_INT actual_val = INTVAL (op_b);
1554 if (actual_val == desired_val + 1)
1557 op_b = GEN_INT (desired_val);
1561 if (actual_val == desired_val - 1)
1564 op_b = GEN_INT (desired_val);
1568 if (actual_val == desired_val - 1)
1571 op_b = GEN_INT (desired_val);
1575 if (actual_val == desired_val + 1)
1578 op_b = GEN_INT (desired_val);
1586 /* If we made any changes, generate a new conditional that is
1587 equivalent to what we started with, but has the right
1589 if (code != GET_CODE (if_info->cond)
1590 || op_a != XEXP (if_info->cond, 0)
1591 || op_b != XEXP (if_info->cond, 1))
1593 cond = gen_rtx_fmt_ee (code, GET_MODE (cond), op_a, op_b);
1594 *earliest = if_info->cond_earliest;
1599 cond = canonicalize_condition (if_info->jump, cond, reverse,
1600 earliest, target, false, true);
1601 if (! cond || ! reg_mentioned_p (target, cond))
1604 /* We almost certainly searched back to a different place.
1605 Need to re-verify correct lifetimes. */
1607 /* X may not be mentioned in the range (cond_earliest, jump]. */
1608 for (insn = if_info->jump; insn != *earliest; insn = PREV_INSN (insn))
1609 if (INSN_P (insn) && reg_overlap_mentioned_p (if_info->x, PATTERN (insn)))
1612 /* A and B may not be modified in the range [cond_earliest, jump). */
1613 for (insn = *earliest; insn != if_info->jump; insn = NEXT_INSN (insn))
1615 && (modified_in_p (if_info->a, insn)
1616 || modified_in_p (if_info->b, insn)))
1622 /* Convert "if (a < b) x = a; else x = b;" to "x = min(a, b);", etc. */
1625 noce_try_minmax (struct noce_if_info *if_info)
1627 rtx cond, earliest, target, seq;
1628 enum rtx_code code, op;
1631 /* ??? Can't guarantee that expand_binop won't create pseudos. */
1635 /* ??? Reject modes with NaNs or signed zeros since we don't know how
1636 they will be resolved with an SMIN/SMAX. It wouldn't be too hard
1637 to get the target to tell us... */
1638 if (HONOR_SIGNED_ZEROS (GET_MODE (if_info->x))
1639 || HONOR_NANS (GET_MODE (if_info->x)))
1642 cond = noce_get_alt_condition (if_info, if_info->a, &earliest);
1646 /* Verify the condition is of the form we expect, and canonicalize
1647 the comparison code. */
1648 code = GET_CODE (cond);
1649 if (rtx_equal_p (XEXP (cond, 0), if_info->a))
1651 if (! rtx_equal_p (XEXP (cond, 1), if_info->b))
1654 else if (rtx_equal_p (XEXP (cond, 1), if_info->a))
1656 if (! rtx_equal_p (XEXP (cond, 0), if_info->b))
1658 code = swap_condition (code);
1663 /* Determine what sort of operation this is. Note that the code is for
1664 a taken branch, so the code->operation mapping appears backwards. */
1697 target = expand_simple_binop (GET_MODE (if_info->x), op,
1698 if_info->a, if_info->b,
1699 if_info->x, unsignedp, OPTAB_WIDEN);
1705 if (target != if_info->x)
1706 noce_emit_move_insn (if_info->x, target);
1708 seq = end_ifcvt_sequence (if_info);
1712 emit_insn_before_setloc (seq, if_info->jump, INSN_LOCATOR (if_info->insn_a));
1713 if_info->cond = cond;
1714 if_info->cond_earliest = earliest;
1719 /* Convert "if (a < 0) x = -a; else x = a;" to "x = abs(a);", etc. */
1722 noce_try_abs (struct noce_if_info *if_info)
1724 rtx cond, earliest, target, seq, a, b, c;
1727 /* ??? Can't guarantee that expand_binop won't create pseudos. */
1731 /* Recognize A and B as constituting an ABS or NABS. The canonical
1732 form is a branch around the negation, taken when the object is the
1733 first operand of a comparison against 0 that evaluates to true. */
1736 if (GET_CODE (a) == NEG && rtx_equal_p (XEXP (a, 0), b))
1738 else if (GET_CODE (b) == NEG && rtx_equal_p (XEXP (b, 0), a))
1740 c = a; a = b; b = c;
1746 cond = noce_get_alt_condition (if_info, b, &earliest);
1750 /* Verify the condition is of the form we expect. */
1751 if (rtx_equal_p (XEXP (cond, 0), b))
1753 else if (rtx_equal_p (XEXP (cond, 1), b))
1761 /* Verify that C is zero. Search one step backward for a
1762 REG_EQUAL note or a simple source if necessary. */
1765 rtx set, insn = prev_nonnote_insn (earliest);
1767 && (set = single_set (insn))
1768 && rtx_equal_p (SET_DEST (set), c))
1770 rtx note = find_reg_equal_equiv_note (insn);
1780 && GET_CODE (XEXP (c, 0)) == SYMBOL_REF
1781 && CONSTANT_POOL_ADDRESS_P (XEXP (c, 0)))
1782 c = get_pool_constant (XEXP (c, 0));
1784 /* Work around funny ideas get_condition has wrt canonicalization.
1785 Note that these rtx constants are known to be CONST_INT, and
1786 therefore imply integer comparisons. */
1787 if (c == constm1_rtx && GET_CODE (cond) == GT)
1789 else if (c == const1_rtx && GET_CODE (cond) == LT)
1791 else if (c != CONST0_RTX (GET_MODE (b)))
1794 /* Determine what sort of operation this is. */
1795 switch (GET_CODE (cond))
1814 target = expand_abs_nojump (GET_MODE (if_info->x), b, if_info->x, 1);
1816 /* ??? It's a quandary whether cmove would be better here, especially
1817 for integers. Perhaps combine will clean things up. */
1818 if (target && negate)
1819 target = expand_simple_unop (GET_MODE (target), NEG, target, if_info->x, 0);
1827 if (target != if_info->x)
1828 noce_emit_move_insn (if_info->x, target);
1830 seq = end_ifcvt_sequence (if_info);
1834 emit_insn_before_setloc (seq, if_info->jump, INSN_LOCATOR (if_info->insn_a));
1835 if_info->cond = cond;
1836 if_info->cond_earliest = earliest;
1841 /* Convert "if (m < 0) x = b; else x = 0;" to "x = (m >> C) & b;". */
1844 noce_try_sign_mask (struct noce_if_info *if_info)
1846 rtx cond, t, m, c, seq;
1847 enum machine_mode mode;
1853 cond = if_info->cond;
1854 code = GET_CODE (cond);
1859 if (if_info->a == const0_rtx)
1861 if ((code == LT && c == const0_rtx)
1862 || (code == LE && c == constm1_rtx))
1865 else if (if_info->b == const0_rtx)
1867 if ((code == GE && c == const0_rtx)
1868 || (code == GT && c == constm1_rtx))
1872 if (! t || side_effects_p (t))
1875 /* We currently don't handle different modes. */
1876 mode = GET_MODE (t);
1877 if (GET_MODE (m) != mode)
1880 /* This is only profitable if T is cheap, or T is unconditionally
1881 executed/evaluated in the original insn sequence. */
1882 if (rtx_cost (t, SET) >= COSTS_N_INSNS (2)
1883 && (!if_info->b_unconditional
1884 || t != if_info->b))
1888 /* Use emit_store_flag to generate "m < 0 ? -1 : 0" instead of expanding
1889 "(signed) m >> 31" directly. This benefits targets with specialized
1890 insns to obtain the signmask, but still uses ashr_optab otherwise. */
1891 m = emit_store_flag (gen_reg_rtx (mode), LT, m, const0_rtx, mode, 0, -1);
1892 t = m ? expand_binop (mode, and_optab, m, t, NULL_RTX, 0, OPTAB_DIRECT)
1901 noce_emit_move_insn (if_info->x, t);
1903 seq = end_ifcvt_sequence (if_info);
1907 emit_insn_before_setloc (seq, if_info->jump, INSN_LOCATOR (if_info->insn_a));
1912 /* Optimize away "if (x & C) x |= C" and similar bit manipulation
1916 noce_try_bitop (struct noce_if_info *if_info)
1918 rtx cond, x, a, result, seq;
1919 enum machine_mode mode;
1924 cond = if_info->cond;
1925 code = GET_CODE (cond);
1927 /* Check for no else condition. */
1928 if (! rtx_equal_p (x, if_info->b))
1931 /* Check for a suitable condition. */
1932 if (code != NE && code != EQ)
1934 if (XEXP (cond, 1) != const0_rtx)
1936 cond = XEXP (cond, 0);
1938 /* ??? We could also handle AND here. */
1939 if (GET_CODE (cond) == ZERO_EXTRACT)
1941 if (XEXP (cond, 1) != const1_rtx
1942 || GET_CODE (XEXP (cond, 2)) != CONST_INT
1943 || ! rtx_equal_p (x, XEXP (cond, 0)))
1945 bitnum = INTVAL (XEXP (cond, 2));
1946 mode = GET_MODE (x);
1947 if (bitnum >= HOST_BITS_PER_WIDE_INT)
1954 if (GET_CODE (a) == IOR || GET_CODE (a) == XOR)
1956 /* Check for "if (X & C) x = x op C". */
1957 if (! rtx_equal_p (x, XEXP (a, 0))
1958 || GET_CODE (XEXP (a, 1)) != CONST_INT
1959 || (INTVAL (XEXP (a, 1)) & GET_MODE_MASK (mode))
1960 != (unsigned HOST_WIDE_INT) 1 << bitnum)
1963 /* if ((x & C) == 0) x |= C; is transformed to x |= C. */
1964 /* if ((x & C) != 0) x |= C; is transformed to nothing. */
1965 if (GET_CODE (a) == IOR)
1966 result = (code == NE) ? a : NULL_RTX;
1967 else if (code == NE)
1969 /* if ((x & C) == 0) x ^= C; is transformed to x |= C. */
1970 result = gen_int_mode ((HOST_WIDE_INT) 1 << bitnum, mode);
1971 result = simplify_gen_binary (IOR, mode, x, result);
1975 /* if ((x & C) != 0) x ^= C; is transformed to x &= ~C. */
1976 result = gen_int_mode (~((HOST_WIDE_INT) 1 << bitnum), mode);
1977 result = simplify_gen_binary (AND, mode, x, result);
1980 else if (GET_CODE (a) == AND)
1982 /* Check for "if (X & C) x &= ~C". */
1983 if (! rtx_equal_p (x, XEXP (a, 0))
1984 || GET_CODE (XEXP (a, 1)) != CONST_INT
1985 || (INTVAL (XEXP (a, 1)) & GET_MODE_MASK (mode))
1986 != (~((HOST_WIDE_INT) 1 << bitnum) & GET_MODE_MASK (mode)))
1989 /* if ((x & C) == 0) x &= ~C; is transformed to nothing. */
1990 /* if ((x & C) != 0) x &= ~C; is transformed to x &= ~C. */
1991 result = (code == EQ) ? a : NULL_RTX;
1999 noce_emit_move_insn (x, result);
2000 seq = end_ifcvt_sequence (if_info);
2004 emit_insn_before_setloc (seq, if_info->jump,
2005 INSN_LOCATOR (if_info->insn_a));
2011 /* Similar to get_condition, only the resulting condition must be
2012 valid at JUMP, instead of at EARLIEST. */
2015 noce_get_condition (rtx jump, rtx *earliest)
2020 if (! any_condjump_p (jump))
2023 set = pc_set (jump);
2025 /* If this branches to JUMP_LABEL when the condition is false,
2026 reverse the condition. */
2027 reverse = (GET_CODE (XEXP (SET_SRC (set), 2)) == LABEL_REF
2028 && XEXP (XEXP (SET_SRC (set), 2), 0) == JUMP_LABEL (jump));
2030 /* If the condition variable is a register and is MODE_INT, accept it. */
2032 cond = XEXP (SET_SRC (set), 0);
2033 tmp = XEXP (cond, 0);
2034 if (REG_P (tmp) && GET_MODE_CLASS (GET_MODE (tmp)) == MODE_INT)
2039 cond = gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond)),
2040 GET_MODE (cond), tmp, XEXP (cond, 1));
2044 /* Otherwise, fall back on canonicalize_condition to do the dirty
2045 work of manipulating MODE_CC values and COMPARE rtx codes. */
2046 return canonicalize_condition (jump, cond, reverse, earliest,
2047 NULL_RTX, false, true);
2050 /* Initialize for a simple IF-THEN or IF-THEN-ELSE block. We will not
2051 be using conditional execution. Set some fields of IF_INFO based
2052 on CE_INFO: test_bb, cond, jump, cond_earliest. Return TRUE if
2056 noce_init_if_info (struct ce_if_block *ce_info, struct noce_if_info *if_info)
2058 basic_block test_bb = ce_info->test_bb;
2061 /* If test is comprised of && or || elements, don't handle it unless
2062 it is the special case of && elements without an ELSE block. */
2063 if (ce_info->num_multiple_test_blocks)
2065 if (ce_info->else_bb || !ce_info->and_and_p)
2068 ce_info->test_bb = test_bb = ce_info->last_test_bb;
2069 ce_info->num_multiple_test_blocks = 0;
2070 ce_info->num_and_and_blocks = 0;
2071 ce_info->num_or_or_blocks = 0;
2074 /* If this is not a standard conditional jump, we can't parse it. */
2075 jump = BB_END (test_bb);
2076 cond = noce_get_condition (jump, &if_info->cond_earliest);
2080 /* If the conditional jump is more than just a conditional
2081 jump, then we can not do if-conversion on this block. */
2082 if (! onlyjump_p (jump))
2085 /* We must be comparing objects whose modes imply the size. */
2086 if (GET_MODE (XEXP (cond, 0)) == BLKmode)
2089 if_info->test_bb = test_bb;
2090 if_info->cond = cond;
2091 if_info->jump = jump;
2096 /* Return true if OP is ok for if-then-else processing. */
2099 noce_operand_ok (rtx op)
2101 /* We special-case memories, so handle any of them with
2102 no address side effects. */
2104 return ! side_effects_p (XEXP (op, 0));
2106 if (side_effects_p (op))
2109 return ! may_trap_p (op);
2112 /* Return true if a write into MEM may trap or fault. */
2115 noce_mem_write_may_trap_or_fault_p (rtx mem)
2119 if (MEM_READONLY_P (mem))
2122 if (may_trap_or_fault_p (mem))
2125 addr = XEXP (mem, 0);
2127 /* Call target hook to avoid the effects of -fpic etc.... */
2128 addr = targetm.delegitimize_address (addr);
2131 switch (GET_CODE (addr))
2139 addr = XEXP (addr, 0);
2143 addr = XEXP (addr, 1);
2146 if (GET_CODE (XEXP (addr, 1)) == CONST_INT)
2147 addr = XEXP (addr, 0);
2154 if (SYMBOL_REF_DECL (addr)
2155 && decl_readonly_section (SYMBOL_REF_DECL (addr), 0))
2165 /* Given a simple IF-THEN or IF-THEN-ELSE block, attempt to convert it
2166 without using conditional execution. Return TRUE if we were
2167 successful at converting the block. */
2170 noce_process_if_block (struct ce_if_block * ce_info)
2172 basic_block test_bb = ce_info->test_bb; /* test block */
2173 basic_block then_bb = ce_info->then_bb; /* THEN */
2174 basic_block else_bb = ce_info->else_bb; /* ELSE or NULL */
2175 struct noce_if_info if_info;
2178 rtx orig_x, x, a, b;
2181 /* We're looking for patterns of the form
2183 (1) if (...) x = a; else x = b;
2184 (2) x = b; if (...) x = a;
2185 (3) if (...) x = a; // as if with an initial x = x.
2187 The later patterns require jumps to be more expensive.
2189 ??? For future expansion, look for multiple X in such patterns. */
2191 if (!noce_init_if_info (ce_info, &if_info))
2194 cond = if_info.cond;
2195 jump = if_info.jump;
2197 /* Look for one of the potential sets. */
2198 insn_a = first_active_insn (then_bb);
2200 || insn_a != last_active_insn (then_bb, FALSE)
2201 || (set_a = single_set (insn_a)) == NULL_RTX)
2204 x = SET_DEST (set_a);
2205 a = SET_SRC (set_a);
2207 /* Look for the other potential set. Make sure we've got equivalent
2209 /* ??? This is overconservative. Storing to two different mems is
2210 as easy as conditionally computing the address. Storing to a
2211 single mem merely requires a scratch memory to use as one of the
2212 destination addresses; often the memory immediately below the
2213 stack pointer is available for this. */
2217 insn_b = first_active_insn (else_bb);
2219 || insn_b != last_active_insn (else_bb, FALSE)
2220 || (set_b = single_set (insn_b)) == NULL_RTX
2221 || ! rtx_equal_p (x, SET_DEST (set_b)))
2226 insn_b = prev_nonnote_insn (if_info.cond_earliest);
2227 /* We're going to be moving the evaluation of B down from above
2228 COND_EARLIEST to JUMP. Make sure the relevant data is still
2231 || !NONJUMP_INSN_P (insn_b)
2232 || (set_b = single_set (insn_b)) == NULL_RTX
2233 || ! rtx_equal_p (x, SET_DEST (set_b))
2234 || reg_overlap_mentioned_p (x, SET_SRC (set_b))
2235 || modified_between_p (SET_SRC (set_b),
2236 PREV_INSN (if_info.cond_earliest), jump)
2237 /* Likewise with X. In particular this can happen when
2238 noce_get_condition looks farther back in the instruction
2239 stream than one might expect. */
2240 || reg_overlap_mentioned_p (x, cond)
2241 || reg_overlap_mentioned_p (x, a)
2242 || modified_between_p (x, PREV_INSN (if_info.cond_earliest), jump))
2243 insn_b = set_b = NULL_RTX;
2246 /* If x has side effects then only the if-then-else form is safe to
2247 convert. But even in that case we would need to restore any notes
2248 (such as REG_INC) at then end. That can be tricky if
2249 noce_emit_move_insn expands to more than one insn, so disable the
2250 optimization entirely for now if there are side effects. */
2251 if (side_effects_p (x))
2254 b = (set_b ? SET_SRC (set_b) : x);
2256 /* Only operate on register destinations, and even then avoid extending
2257 the lifetime of hard registers on small register class machines. */
2260 || (SMALL_REGISTER_CLASSES
2261 && REGNO (x) < FIRST_PSEUDO_REGISTER))
2263 if (no_new_pseudos || GET_MODE (x) == BLKmode)
2266 if (GET_MODE (x) == ZERO_EXTRACT
2267 && (GET_CODE (XEXP (x, 1)) != CONST_INT
2268 || GET_CODE (XEXP (x, 2)) != CONST_INT))
2271 x = gen_reg_rtx (GET_MODE (GET_CODE (x) == STRICT_LOW_PART
2272 ? XEXP (x, 0) : x));
2275 /* Don't operate on sources that may trap or are volatile. */
2276 if (! noce_operand_ok (a) || ! noce_operand_ok (b))
2279 /* Set up the info block for our subroutines. */
2280 if_info.insn_a = insn_a;
2281 if_info.insn_b = insn_b;
2285 if_info.b_unconditional = else_bb == 0;
2287 /* Try optimizations in some approximation of a useful order. */
2288 /* ??? Should first look to see if X is live incoming at all. If it
2289 isn't, we don't need anything but an unconditional set. */
2291 /* Look and see if A and B are really the same. Avoid creating silly
2292 cmove constructs that no one will fix up later. */
2293 if (rtx_equal_p (a, b))
2295 /* If we have an INSN_B, we don't have to create any new rtl. Just
2296 move the instruction that we already have. If we don't have an
2297 INSN_B, that means that A == X, and we've got a noop move. In
2298 that case don't do anything and let the code below delete INSN_A. */
2299 if (insn_b && else_bb)
2303 if (else_bb && insn_b == BB_END (else_bb))
2304 BB_END (else_bb) = PREV_INSN (insn_b);
2305 reorder_insns (insn_b, insn_b, PREV_INSN (jump));
2307 /* If there was a REG_EQUAL note, delete it since it may have been
2308 true due to this insn being after a jump. */
2309 if ((note = find_reg_note (insn_b, REG_EQUAL, NULL_RTX)) != 0)
2310 remove_note (insn_b, note);
2314 /* If we have "x = b; if (...) x = a;", and x has side-effects, then
2315 x must be executed twice. */
2316 else if (insn_b && side_effects_p (orig_x))
2323 /* Disallow the "if (...) x = a;" form (with an implicit "else x = x;")
2324 for optimizations if writing to x may trap or fault, i.e. it's a memory
2325 other than a static var or a stack slot, is misaligned on strict
2326 aligned machines or is read-only.
2327 If x is a read-only memory, then the program is valid only if we
2328 avoid the store into it. If there are stores on both the THEN and
2329 ELSE arms, then we can go ahead with the conversion; either the
2330 program is broken, or the condition is always false such that the
2331 other memory is selected. */
2332 if (!set_b && MEM_P (orig_x) && noce_mem_write_may_trap_or_fault_p (orig_x))
2335 if (noce_try_move (&if_info))
2337 if (noce_try_store_flag (&if_info))
2339 if (noce_try_bitop (&if_info))
2341 if (noce_try_minmax (&if_info))
2343 if (noce_try_abs (&if_info))
2345 if (HAVE_conditional_move
2346 && noce_try_cmove (&if_info))
2348 if (! HAVE_conditional_execution)
2350 if (noce_try_store_flag_constants (&if_info))
2352 if (noce_try_addcc (&if_info))
2354 if (noce_try_store_flag_mask (&if_info))
2356 if (HAVE_conditional_move
2357 && noce_try_cmove_arith (&if_info))
2359 if (noce_try_sign_mask (&if_info))
2366 /* The original sets may now be killed. */
2367 delete_insn (insn_a);
2369 /* Several special cases here: First, we may have reused insn_b above,
2370 in which case insn_b is now NULL. Second, we want to delete insn_b
2371 if it came from the ELSE block, because follows the now correct
2372 write that appears in the TEST block. However, if we got insn_b from
2373 the TEST block, it may in fact be loading data needed for the comparison.
2374 We'll let life_analysis remove the insn if it's really dead. */
2375 if (insn_b && else_bb)
2376 delete_insn (insn_b);
2378 /* The new insns will have been inserted immediately before the jump. We
2379 should be able to remove the jump with impunity, but the condition itself
2380 may have been modified by gcse to be shared across basic blocks. */
2383 /* If we used a temporary, fix it up now. */
2387 noce_emit_move_insn (orig_x, x);
2388 insn_b = get_insns ();
2389 set_used_flags (orig_x);
2390 unshare_all_rtl_in_chain (insn_b);
2393 emit_insn_after_setloc (insn_b, BB_END (test_bb), INSN_LOCATOR (insn_a));
2396 /* Merge the blocks! */
2397 merge_if_block (ce_info);
2402 /* Check whether a block is suitable for conditional move conversion.
2403 Every insn must be a simple set of a register to a constant or a
2404 register. For each assignment, store the value in the array VALS,
2405 indexed by register number. COND is the condition we will
2409 check_cond_move_block (basic_block bb, rtx *vals, rtx cond)
2413 FOR_BB_INSNS (bb, insn)
2417 if (!INSN_P (insn) || JUMP_P (insn))
2419 set = single_set (insn);
2423 dest = SET_DEST (set);
2424 src = SET_SRC (set);
2426 || (SMALL_REGISTER_CLASSES && HARD_REGISTER_P (dest)))
2429 if (!CONSTANT_P (src) && !register_operand (src, VOIDmode))
2432 if (side_effects_p (src) || side_effects_p (dest))
2435 if (may_trap_p (src) || may_trap_p (dest))
2438 /* Don't try to handle this if the destination register was
2439 modified earlier in the block. */
2440 if (vals[REGNO (dest)] != NULL)
2443 /* Don't try to handle this if the condition uses the
2444 destination register. */
2445 if (reg_overlap_mentioned_p (dest, cond))
2448 vals[REGNO (dest)] = src;
2450 /* Don't try to handle this if the source register is modified
2451 later in the block. */
2452 if (!CONSTANT_P (src)
2453 && modified_between_p (src, insn, NEXT_INSN (BB_END (bb))))
2460 /* Given a simple IF-THEN or IF-THEN-ELSE block, attempt to convert it
2461 using only conditional moves. Return TRUE if we were successful at
2462 converting the block. */
2465 cond_move_process_if_block (struct ce_if_block *ce_info)
2467 basic_block then_bb = ce_info->then_bb;
2468 basic_block else_bb = ce_info->else_bb;
2469 struct noce_if_info if_info;
2470 rtx jump, cond, insn, seq, cond_arg0, cond_arg1, loc_insn;
2471 int max_reg, size, c, i;
2476 if (!HAVE_conditional_move || no_new_pseudos)
2479 memset (&if_info, 0, sizeof if_info);
2481 if (!noce_init_if_info (ce_info, &if_info))
2484 cond = if_info.cond;
2485 jump = if_info.jump;
2487 /* Build a mapping for each block to the value used for each
2489 max_reg = max_reg_num ();
2490 size = (max_reg + 1) * sizeof (rtx);
2491 then_vals = (rtx *) alloca (size);
2492 else_vals = (rtx *) alloca (size);
2493 memset (then_vals, 0, size);
2494 memset (else_vals, 0, size);
2496 /* Make sure the blocks are suitable. */
2497 if (!check_cond_move_block (then_bb, then_vals, cond)
2498 || (else_bb && !check_cond_move_block (else_bb, else_vals, cond)))
2501 /* Make sure the blocks can be used together. If the same register
2502 is set in both blocks, and is not set to a constant in both
2503 cases, then both blocks must set it to the same register. We
2504 have already verified that if it is set to a register, that the
2505 source register does not change after the assignment. Also count
2506 the number of registers set in only one of the blocks. */
2508 for (i = 0; i <= max_reg; ++i)
2510 if (!then_vals[i] && !else_vals[i])
2513 if (!then_vals[i] || !else_vals[i])
2517 if (!CONSTANT_P (then_vals[i])
2518 && !CONSTANT_P (else_vals[i])
2519 && !rtx_equal_p (then_vals[i], else_vals[i]))
2524 /* Make sure it is reasonable to convert this block. What matters
2525 is the number of assignments currently made in only one of the
2526 branches, since if we convert we are going to always execute
2528 if (c > MAX_CONDITIONAL_EXECUTE)
2531 /* Emit the conditional moves. First do the then block, then do
2532 anything left in the else blocks. */
2534 code = GET_CODE (cond);
2535 cond_arg0 = XEXP (cond, 0);
2536 cond_arg1 = XEXP (cond, 1);
2540 FOR_BB_INSNS (then_bb, insn)
2542 rtx set, target, dest, t, e;
2545 if (!INSN_P (insn) || JUMP_P (insn))
2547 set = single_set (insn);
2548 gcc_assert (set && REG_P (SET_DEST (set)));
2550 dest = SET_DEST (set);
2551 regno = REGNO (dest);
2552 t = then_vals[regno];
2553 e = else_vals[regno];
2557 target = noce_emit_cmove (&if_info, dest, code, cond_arg0, cond_arg1,
2566 noce_emit_move_insn (dest, target);
2571 FOR_BB_INSNS (else_bb, insn)
2573 rtx set, target, dest;
2576 if (!INSN_P (insn) || JUMP_P (insn))
2578 set = single_set (insn);
2579 gcc_assert (set && REG_P (SET_DEST (set)));
2581 dest = SET_DEST (set);
2582 regno = REGNO (dest);
2584 /* If this register was set in the then block, we already
2585 handled this case above. */
2586 if (then_vals[regno])
2588 gcc_assert (else_vals[regno]);
2590 target = noce_emit_cmove (&if_info, dest, code, cond_arg0, cond_arg1,
2591 dest, else_vals[regno]);
2599 noce_emit_move_insn (dest, target);
2603 seq = end_ifcvt_sequence (&if_info);
2607 loc_insn = first_active_insn (then_bb);
2610 loc_insn = first_active_insn (else_bb);
2611 gcc_assert (loc_insn);
2613 emit_insn_before_setloc (seq, jump, INSN_LOCATOR (loc_insn));
2615 FOR_BB_INSNS (then_bb, insn)
2616 if (INSN_P (insn) && !JUMP_P (insn))
2620 FOR_BB_INSNS (else_bb, insn)
2621 if (INSN_P (insn) && !JUMP_P (insn))
2626 merge_if_block (ce_info);
2631 /* Attempt to convert an IF-THEN or IF-THEN-ELSE block into
2632 straight line code. Return true if successful. */
2635 process_if_block (struct ce_if_block * ce_info)
2637 if (! reload_completed
2638 && noce_process_if_block (ce_info))
2641 if (HAVE_conditional_move
2642 && cond_move_process_if_block (ce_info))
2645 if (HAVE_conditional_execution && reload_completed)
2647 /* If we have && and || tests, try to first handle combining the && and
2648 || tests into the conditional code, and if that fails, go back and
2649 handle it without the && and ||, which at present handles the && case
2650 if there was no ELSE block. */
2651 if (cond_exec_process_if_block (ce_info, TRUE))
2654 if (ce_info->num_multiple_test_blocks)
2658 if (cond_exec_process_if_block (ce_info, FALSE))
2666 /* Merge the blocks and mark for local life update. */
2669 merge_if_block (struct ce_if_block * ce_info)
2671 basic_block test_bb = ce_info->test_bb; /* last test block */
2672 basic_block then_bb = ce_info->then_bb; /* THEN */
2673 basic_block else_bb = ce_info->else_bb; /* ELSE or NULL */
2674 basic_block join_bb = ce_info->join_bb; /* join block */
2675 basic_block combo_bb;
2677 /* All block merging is done into the lower block numbers. */
2681 /* Merge any basic blocks to handle && and || subtests. Each of
2682 the blocks are on the fallthru path from the predecessor block. */
2683 if (ce_info->num_multiple_test_blocks > 0)
2685 basic_block bb = test_bb;
2686 basic_block last_test_bb = ce_info->last_test_bb;
2687 basic_block fallthru = block_fallthru (bb);
2692 fallthru = block_fallthru (bb);
2693 merge_blocks (combo_bb, bb);
2696 while (bb != last_test_bb);
2699 /* Merge TEST block into THEN block. Normally the THEN block won't have a
2700 label, but it might if there were || tests. That label's count should be
2701 zero, and it normally should be removed. */
2705 if (combo_bb->il.rtl->global_live_at_end)
2706 COPY_REG_SET (combo_bb->il.rtl->global_live_at_end,
2707 then_bb->il.rtl->global_live_at_end);
2708 merge_blocks (combo_bb, then_bb);
2712 /* The ELSE block, if it existed, had a label. That label count
2713 will almost always be zero, but odd things can happen when labels
2714 get their addresses taken. */
2717 merge_blocks (combo_bb, else_bb);
2721 /* If there was no join block reported, that means it was not adjacent
2722 to the others, and so we cannot merge them. */
2726 rtx last = BB_END (combo_bb);
2728 /* The outgoing edge for the current COMBO block should already
2729 be correct. Verify this. */
2730 if (EDGE_COUNT (combo_bb->succs) == 0)
2731 gcc_assert (find_reg_note (last, REG_NORETURN, NULL)
2732 || (NONJUMP_INSN_P (last)
2733 && GET_CODE (PATTERN (last)) == TRAP_IF
2734 && (TRAP_CONDITION (PATTERN (last))
2735 == const_true_rtx)));
2738 /* There should still be something at the end of the THEN or ELSE
2739 blocks taking us to our final destination. */
2740 gcc_assert (JUMP_P (last)
2741 || (EDGE_SUCC (combo_bb, 0)->dest == EXIT_BLOCK_PTR
2743 && SIBLING_CALL_P (last))
2744 || ((EDGE_SUCC (combo_bb, 0)->flags & EDGE_EH)
2745 && can_throw_internal (last)));
2748 /* The JOIN block may have had quite a number of other predecessors too.
2749 Since we've already merged the TEST, THEN and ELSE blocks, we should
2750 have only one remaining edge from our if-then-else diamond. If there
2751 is more than one remaining edge, it must come from elsewhere. There
2752 may be zero incoming edges if the THEN block didn't actually join
2753 back up (as with a call to a non-return function). */
2754 else if (EDGE_COUNT (join_bb->preds) < 2
2755 && join_bb != EXIT_BLOCK_PTR)
2757 /* We can merge the JOIN. */
2758 if (combo_bb->il.rtl->global_live_at_end)
2759 COPY_REG_SET (combo_bb->il.rtl->global_live_at_end,
2760 join_bb->il.rtl->global_live_at_end);
2762 merge_blocks (combo_bb, join_bb);
2767 /* We cannot merge the JOIN. */
2769 /* The outgoing edge for the current COMBO block should already
2770 be correct. Verify this. */
2771 gcc_assert (single_succ_p (combo_bb)
2772 && single_succ (combo_bb) == join_bb);
2774 /* Remove the jump and cruft from the end of the COMBO block. */
2775 if (join_bb != EXIT_BLOCK_PTR)
2776 tidy_fallthru_edge (single_succ_edge (combo_bb));
2779 num_updated_if_blocks++;
2782 /* Find a block ending in a simple IF condition and try to transform it
2783 in some way. When converting a multi-block condition, put the new code
2784 in the first such block and delete the rest. Return a pointer to this
2785 first block if some transformation was done. Return NULL otherwise. */
2788 find_if_header (basic_block test_bb, int pass)
2790 ce_if_block_t ce_info;
2794 /* The kind of block we're looking for has exactly two successors. */
2795 if (EDGE_COUNT (test_bb->succs) != 2)
2798 then_edge = EDGE_SUCC (test_bb, 0);
2799 else_edge = EDGE_SUCC (test_bb, 1);
2801 /* Neither edge should be abnormal. */
2802 if ((then_edge->flags & EDGE_COMPLEX)
2803 || (else_edge->flags & EDGE_COMPLEX))
2806 /* Nor exit the loop. */
2807 if ((then_edge->flags & EDGE_LOOP_EXIT)
2808 || (else_edge->flags & EDGE_LOOP_EXIT))
2811 /* The THEN edge is canonically the one that falls through. */
2812 if (then_edge->flags & EDGE_FALLTHRU)
2814 else if (else_edge->flags & EDGE_FALLTHRU)
2817 else_edge = then_edge;
2821 /* Otherwise this must be a multiway branch of some sort. */
2824 memset (&ce_info, '\0', sizeof (ce_info));
2825 ce_info.test_bb = test_bb;
2826 ce_info.then_bb = then_edge->dest;
2827 ce_info.else_bb = else_edge->dest;
2828 ce_info.pass = pass;
2830 #ifdef IFCVT_INIT_EXTRA_FIELDS
2831 IFCVT_INIT_EXTRA_FIELDS (&ce_info);
2834 if (find_if_block (&ce_info))
2837 if (HAVE_trap && HAVE_conditional_trap
2838 && find_cond_trap (test_bb, then_edge, else_edge))
2841 if (dom_computed[CDI_POST_DOMINATORS] >= DOM_NO_FAST_QUERY
2842 && (! HAVE_conditional_execution || reload_completed))
2844 if (find_if_case_1 (test_bb, then_edge, else_edge))
2846 if (find_if_case_2 (test_bb, then_edge, else_edge))
2854 fprintf (dump_file, "Conversion succeeded on pass %d.\n", pass);
2855 return ce_info.test_bb;
2858 /* Return true if a block has two edges, one of which falls through to the next
2859 block, and the other jumps to a specific block, so that we can tell if the
2860 block is part of an && test or an || test. Returns either -1 or the number
2861 of non-note, non-jump, non-USE/CLOBBER insns in the block. */
2864 block_jumps_and_fallthru_p (basic_block cur_bb, basic_block target_bb)
2867 int fallthru_p = FALSE;
2874 if (!cur_bb || !target_bb)
2877 /* If no edges, obviously it doesn't jump or fallthru. */
2878 if (EDGE_COUNT (cur_bb->succs) == 0)
2881 FOR_EACH_EDGE (cur_edge, ei, cur_bb->succs)
2883 if (cur_edge->flags & EDGE_COMPLEX)
2884 /* Anything complex isn't what we want. */
2887 else if (cur_edge->flags & EDGE_FALLTHRU)
2890 else if (cur_edge->dest == target_bb)
2897 if ((jump_p & fallthru_p) == 0)
2900 /* Don't allow calls in the block, since this is used to group && and ||
2901 together for conditional execution support. ??? we should support
2902 conditional execution support across calls for IA-64 some day, but
2903 for now it makes the code simpler. */
2904 end = BB_END (cur_bb);
2905 insn = BB_HEAD (cur_bb);
2907 while (insn != NULL_RTX)
2914 && GET_CODE (PATTERN (insn)) != USE
2915 && GET_CODE (PATTERN (insn)) != CLOBBER)
2921 insn = NEXT_INSN (insn);
2927 /* Determine if a given basic block heads a simple IF-THEN or IF-THEN-ELSE
2928 block. If so, we'll try to convert the insns to not require the branch.
2929 Return TRUE if we were successful at converting the block. */
2932 find_if_block (struct ce_if_block * ce_info)
2934 basic_block test_bb = ce_info->test_bb;
2935 basic_block then_bb = ce_info->then_bb;
2936 basic_block else_bb = ce_info->else_bb;
2937 basic_block join_bb = NULL_BLOCK;
2942 ce_info->last_test_bb = test_bb;
2944 /* Discover if any fall through predecessors of the current test basic block
2945 were && tests (which jump to the else block) or || tests (which jump to
2947 if (HAVE_conditional_execution && reload_completed
2948 && single_pred_p (test_bb)
2949 && single_pred_edge (test_bb)->flags == EDGE_FALLTHRU)
2951 basic_block bb = single_pred (test_bb);
2952 basic_block target_bb;
2953 int max_insns = MAX_CONDITIONAL_EXECUTE;
2956 /* Determine if the preceding block is an && or || block. */
2957 if ((n_insns = block_jumps_and_fallthru_p (bb, else_bb)) >= 0)
2959 ce_info->and_and_p = TRUE;
2960 target_bb = else_bb;
2962 else if ((n_insns = block_jumps_and_fallthru_p (bb, then_bb)) >= 0)
2964 ce_info->and_and_p = FALSE;
2965 target_bb = then_bb;
2968 target_bb = NULL_BLOCK;
2970 if (target_bb && n_insns <= max_insns)
2972 int total_insns = 0;
2975 ce_info->last_test_bb = test_bb;
2977 /* Found at least one && or || block, look for more. */
2980 ce_info->test_bb = test_bb = bb;
2981 total_insns += n_insns;
2984 if (!single_pred_p (bb))
2987 bb = single_pred (bb);
2988 n_insns = block_jumps_and_fallthru_p (bb, target_bb);
2990 while (n_insns >= 0 && (total_insns + n_insns) <= max_insns);
2992 ce_info->num_multiple_test_blocks = blocks;
2993 ce_info->num_multiple_test_insns = total_insns;
2995 if (ce_info->and_and_p)
2996 ce_info->num_and_and_blocks = blocks;
2998 ce_info->num_or_or_blocks = blocks;
3002 /* The THEN block of an IF-THEN combo must have exactly one predecessor,
3003 other than any || blocks which jump to the THEN block. */
3004 if ((EDGE_COUNT (then_bb->preds) - ce_info->num_or_or_blocks) != 1)
3007 /* The edges of the THEN and ELSE blocks cannot have complex edges. */
3008 FOR_EACH_EDGE (cur_edge, ei, then_bb->preds)
3010 if (cur_edge->flags & EDGE_COMPLEX)
3014 FOR_EACH_EDGE (cur_edge, ei, else_bb->preds)
3016 if (cur_edge->flags & EDGE_COMPLEX)
3020 /* The THEN block of an IF-THEN combo must have zero or one successors. */
3021 if (EDGE_COUNT (then_bb->succs) > 0
3022 && (!single_succ_p (then_bb)
3023 || (single_succ_edge (then_bb)->flags & EDGE_COMPLEX)
3024 || (flow2_completed && tablejump_p (BB_END (then_bb), NULL, NULL))))
3027 /* If the THEN block has no successors, conditional execution can still
3028 make a conditional call. Don't do this unless the ELSE block has
3029 only one incoming edge -- the CFG manipulation is too ugly otherwise.
3030 Check for the last insn of the THEN block being an indirect jump, which
3031 is listed as not having any successors, but confuses the rest of the CE
3032 code processing. ??? we should fix this in the future. */
3033 if (EDGE_COUNT (then_bb->succs) == 0)
3035 if (single_pred_p (else_bb))
3037 rtx last_insn = BB_END (then_bb);
3040 && NOTE_P (last_insn)
3041 && last_insn != BB_HEAD (then_bb))
3042 last_insn = PREV_INSN (last_insn);
3045 && JUMP_P (last_insn)
3046 && ! simplejump_p (last_insn))
3050 else_bb = NULL_BLOCK;
3056 /* If the THEN block's successor is the other edge out of the TEST block,
3057 then we have an IF-THEN combo without an ELSE. */
3058 else if (single_succ (then_bb) == else_bb)
3061 else_bb = NULL_BLOCK;
3064 /* If the THEN and ELSE block meet in a subsequent block, and the ELSE
3065 has exactly one predecessor and one successor, and the outgoing edge
3066 is not complex, then we have an IF-THEN-ELSE combo. */
3067 else if (single_succ_p (else_bb)
3068 && single_succ (then_bb) == single_succ (else_bb)
3069 && single_pred_p (else_bb)
3070 && ! (single_succ_edge (else_bb)->flags & EDGE_COMPLEX)
3071 && ! (flow2_completed && tablejump_p (BB_END (else_bb), NULL, NULL)))
3072 join_bb = single_succ (else_bb);
3074 /* Otherwise it is not an IF-THEN or IF-THEN-ELSE combination. */
3078 num_possible_if_blocks++;
3083 "\nIF-THEN%s block found, pass %d, start block %d "
3084 "[insn %d], then %d [%d]",
3085 (else_bb) ? "-ELSE" : "",
3088 BB_HEAD (test_bb) ? (int)INSN_UID (BB_HEAD (test_bb)) : -1,
3090 BB_HEAD (then_bb) ? (int)INSN_UID (BB_HEAD (then_bb)) : -1);
3093 fprintf (dump_file, ", else %d [%d]",
3095 BB_HEAD (else_bb) ? (int)INSN_UID (BB_HEAD (else_bb)) : -1);
3097 fprintf (dump_file, ", join %d [%d]",
3099 BB_HEAD (join_bb) ? (int)INSN_UID (BB_HEAD (join_bb)) : -1);
3101 if (ce_info->num_multiple_test_blocks > 0)
3102 fprintf (dump_file, ", %d %s block%s last test %d [%d]",
3103 ce_info->num_multiple_test_blocks,
3104 (ce_info->and_and_p) ? "&&" : "||",
3105 (ce_info->num_multiple_test_blocks == 1) ? "" : "s",
3106 ce_info->last_test_bb->index,
3107 ((BB_HEAD (ce_info->last_test_bb))
3108 ? (int)INSN_UID (BB_HEAD (ce_info->last_test_bb))
3111 fputc ('\n', dump_file);
3114 /* Make sure IF, THEN, and ELSE, blocks are adjacent. Actually, we get the
3115 first condition for free, since we've already asserted that there's a
3116 fallthru edge from IF to THEN. Likewise for the && and || blocks, since
3117 we checked the FALLTHRU flag, those are already adjacent to the last IF
3119 /* ??? As an enhancement, move the ELSE block. Have to deal with
3120 BLOCK notes, if by no other means than backing out the merge if they
3121 exist. Sticky enough I don't want to think about it now. */
3123 if (else_bb && (next = next->next_bb) != else_bb)
3125 if ((next = next->next_bb) != join_bb && join_bb != EXIT_BLOCK_PTR)
3133 /* Do the real work. */
3134 ce_info->else_bb = else_bb;
3135 ce_info->join_bb = join_bb;
3137 return process_if_block (ce_info);
3140 /* Convert a branch over a trap, or a branch
3141 to a trap, into a conditional trap. */
3144 find_cond_trap (basic_block test_bb, edge then_edge, edge else_edge)
3146 basic_block then_bb = then_edge->dest;
3147 basic_block else_bb = else_edge->dest;
3148 basic_block other_bb, trap_bb;
3149 rtx trap, jump, cond, cond_earliest, seq;
3152 /* Locate the block with the trap instruction. */
3153 /* ??? While we look for no successors, we really ought to allow
3154 EH successors. Need to fix merge_if_block for that to work. */
3155 if ((trap = block_has_only_trap (then_bb)) != NULL)
3156 trap_bb = then_bb, other_bb = else_bb;
3157 else if ((trap = block_has_only_trap (else_bb)) != NULL)
3158 trap_bb = else_bb, other_bb = then_bb;
3164 fprintf (dump_file, "\nTRAP-IF block found, start %d, trap %d\n",
3165 test_bb->index, trap_bb->index);
3168 /* If this is not a standard conditional jump, we can't parse it. */
3169 jump = BB_END (test_bb);
3170 cond = noce_get_condition (jump, &cond_earliest);
3174 /* If the conditional jump is more than just a conditional jump, then
3175 we can not do if-conversion on this block. */
3176 if (! onlyjump_p (jump))
3179 /* We must be comparing objects whose modes imply the size. */
3180 if (GET_MODE (XEXP (cond, 0)) == BLKmode)
3183 /* Reverse the comparison code, if necessary. */
3184 code = GET_CODE (cond);
3185 if (then_bb == trap_bb)
3187 code = reversed_comparison_code (cond, jump);
3188 if (code == UNKNOWN)
3192 /* Attempt to generate the conditional trap. */
3193 seq = gen_cond_trap (code, XEXP (cond, 0),
3195 TRAP_CODE (PATTERN (trap)));
3201 /* Emit the new insns before cond_earliest. */
3202 emit_insn_before_setloc (seq, cond_earliest, INSN_LOCATOR (trap));
3204 /* Delete the trap block if possible. */
3205 remove_edge (trap_bb == then_bb ? then_edge : else_edge);
3206 if (EDGE_COUNT (trap_bb->preds) == 0)
3207 delete_basic_block (trap_bb);
3209 /* If the non-trap block and the test are now adjacent, merge them.
3210 Otherwise we must insert a direct branch. */
3211 if (test_bb->next_bb == other_bb)
3213 struct ce_if_block new_ce_info;
3215 memset (&new_ce_info, '\0', sizeof (new_ce_info));
3216 new_ce_info.test_bb = test_bb;
3217 new_ce_info.then_bb = NULL;
3218 new_ce_info.else_bb = NULL;
3219 new_ce_info.join_bb = other_bb;
3220 merge_if_block (&new_ce_info);
3226 lab = JUMP_LABEL (jump);
3227 newjump = emit_jump_insn_after (gen_jump (lab), jump);
3228 LABEL_NUSES (lab) += 1;
3229 JUMP_LABEL (newjump) = lab;
3230 emit_barrier_after (newjump);
3238 /* Subroutine of find_cond_trap: if BB contains only a trap insn,
3242 block_has_only_trap (basic_block bb)
3246 /* We're not the exit block. */
3247 if (bb == EXIT_BLOCK_PTR)
3250 /* The block must have no successors. */
3251 if (EDGE_COUNT (bb->succs) > 0)
3254 /* The only instruction in the THEN block must be the trap. */
3255 trap = first_active_insn (bb);
3256 if (! (trap == BB_END (bb)
3257 && GET_CODE (PATTERN (trap)) == TRAP_IF
3258 && TRAP_CONDITION (PATTERN (trap)) == const_true_rtx))
3264 /* Look for IF-THEN-ELSE cases in which one of THEN or ELSE is
3265 transformable, but not necessarily the other. There need be no
3268 Return TRUE if we were successful at converting the block.
3270 Cases we'd like to look at:
3273 if (test) goto over; // x not live
3281 if (! test) goto label;
3284 if (test) goto E; // x not live
3298 (3) // This one's really only interesting for targets that can do
3299 // multiway branching, e.g. IA-64 BBB bundles. For other targets
3300 // it results in multiple branches on a cache line, which often
3301 // does not sit well with predictors.
3303 if (test1) goto E; // predicted not taken
3319 (A) Don't do (2) if the branch is predicted against the block we're
3320 eliminating. Do it anyway if we can eliminate a branch; this requires
3321 that the sole successor of the eliminated block postdominate the other
3324 (B) With CE, on (3) we can steal from both sides of the if, creating
3333 Again, this is most useful if J postdominates.
3335 (C) CE substitutes for helpful life information.
3337 (D) These heuristics need a lot of work. */
3339 /* Tests for case 1 above. */
3342 find_if_case_1 (basic_block test_bb, edge then_edge, edge else_edge)
3344 basic_block then_bb = then_edge->dest;
3345 basic_block else_bb = else_edge->dest, new_bb;
3348 /* If we are partitioning hot/cold basic blocks, we don't want to
3349 mess up unconditional or indirect jumps that cross between hot
3352 Basic block partitioning may result in some jumps that appear to
3353 be optimizable (or blocks that appear to be mergeable), but which really
3354 must be left untouched (they are required to make it safely across
3355 partition boundaries). See the comments at the top of
3356 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
3358 if ((BB_END (then_bb)
3359 && find_reg_note (BB_END (then_bb), REG_CROSSING_JUMP, NULL_RTX))
3360 || (BB_END (test_bb)
3361 && find_reg_note (BB_END (test_bb), REG_CROSSING_JUMP, NULL_RTX))
3362 || (BB_END (else_bb)
3363 && find_reg_note (BB_END (else_bb), REG_CROSSING_JUMP,
3367 /* THEN has one successor. */
3368 if (!single_succ_p (then_bb))
3371 /* THEN does not fall through, but is not strange either. */
3372 if (single_succ_edge (then_bb)->flags & (EDGE_COMPLEX | EDGE_FALLTHRU))
3375 /* THEN has one predecessor. */
3376 if (!single_pred_p (then_bb))
3379 /* THEN must do something. */
3380 if (forwarder_block_p (then_bb))
3383 num_possible_if_blocks++;
3386 "\nIF-CASE-1 found, start %d, then %d\n",
3387 test_bb->index, then_bb->index);
3389 /* THEN is small. */
3390 if (! cheap_bb_rtx_cost_p (then_bb, COSTS_N_INSNS (BRANCH_COST)))
3393 /* Registers set are dead, or are predicable. */
3394 if (! dead_or_predicable (test_bb, then_bb, else_bb,
3395 single_succ (then_bb), 1))
3398 /* Conversion went ok, including moving the insns and fixing up the
3399 jump. Adjust the CFG to match. */
3401 bitmap_ior (test_bb->il.rtl->global_live_at_end,
3402 else_bb->il.rtl->global_live_at_start,
3403 then_bb->il.rtl->global_live_at_end);
3406 /* We can avoid creating a new basic block if then_bb is immediately
3407 followed by else_bb, i.e. deleting then_bb allows test_bb to fall
3410 if (then_bb->next_bb == else_bb
3411 && then_bb->prev_bb == test_bb
3412 && else_bb != EXIT_BLOCK_PTR)
3414 redirect_edge_succ (FALLTHRU_EDGE (test_bb), else_bb);
3418 new_bb = redirect_edge_and_branch_force (FALLTHRU_EDGE (test_bb),
3421 then_bb_index = then_bb->index;
3422 delete_basic_block (then_bb);
3424 /* Make rest of code believe that the newly created block is the THEN_BB
3425 block we removed. */
3428 new_bb->index = then_bb_index;
3429 SET_BASIC_BLOCK (then_bb_index, new_bb);
3430 /* Since the fallthru edge was redirected from test_bb to new_bb,
3431 we need to ensure that new_bb is in the same partition as
3432 test bb (you can not fall through across section boundaries). */
3433 BB_COPY_PARTITION (new_bb, test_bb);
3435 /* We've possibly created jump to next insn, cleanup_cfg will solve that
3439 num_updated_if_blocks++;
3444 /* Test for case 2 above. */
3447 find_if_case_2 (basic_block test_bb, edge then_edge, edge else_edge)
3449 basic_block then_bb = then_edge->dest;
3450 basic_block else_bb = else_edge->dest;
3454 /* If we are partitioning hot/cold basic blocks, we don't want to
3455 mess up unconditional or indirect jumps that cross between hot
3458 Basic block partitioning may result in some jumps that appear to
3459 be optimizable (or blocks that appear to be mergeable), but which really
3460 must be left untouched (they are required to make it safely across
3461 partition boundaries). See the comments at the top of
3462 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
3464 if ((BB_END (then_bb)
3465 && find_reg_note (BB_END (then_bb), REG_CROSSING_JUMP, NULL_RTX))
3466 || (BB_END (test_bb)
3467 && find_reg_note (BB_END (test_bb), REG_CROSSING_JUMP, NULL_RTX))
3468 || (BB_END (else_bb)
3469 && find_reg_note (BB_END (else_bb), REG_CROSSING_JUMP,
3473 /* ELSE has one successor. */
3474 if (!single_succ_p (else_bb))
3477 else_succ = single_succ_edge (else_bb);
3479 /* ELSE outgoing edge is not complex. */
3480 if (else_succ->flags & EDGE_COMPLEX)
3483 /* ELSE has one predecessor. */
3484 if (!single_pred_p (else_bb))
3487 /* THEN is not EXIT. */
3488 if (then_bb->index < NUM_FIXED_BLOCKS)
3491 /* ELSE is predicted or SUCC(ELSE) postdominates THEN. */
3492 note = find_reg_note (BB_END (test_bb), REG_BR_PROB, NULL_RTX);
3493 if (note && INTVAL (XEXP (note, 0)) >= REG_BR_PROB_BASE / 2)
3495 else if (else_succ->dest->index < NUM_FIXED_BLOCKS
3496 || dominated_by_p (CDI_POST_DOMINATORS, then_bb,
3502 num_possible_if_blocks++;
3505 "\nIF-CASE-2 found, start %d, else %d\n",
3506 test_bb->index, else_bb->index);
3508 /* ELSE is small. */
3509 if (! cheap_bb_rtx_cost_p (else_bb, COSTS_N_INSNS (BRANCH_COST)))
3512 /* Registers set are dead, or are predicable. */
3513 if (! dead_or_predicable (test_bb, else_bb, then_bb, else_succ->dest, 0))
3516 /* Conversion went ok, including moving the insns and fixing up the
3517 jump. Adjust the CFG to match. */
3519 bitmap_ior (test_bb->il.rtl->global_live_at_end,
3520 then_bb->il.rtl->global_live_at_start,
3521 else_bb->il.rtl->global_live_at_end);
3523 delete_basic_block (else_bb);
3526 num_updated_if_blocks++;
3528 /* ??? We may now fallthru from one of THEN's successors into a join
3529 block. Rerun cleanup_cfg? Examine things manually? Wait? */
3534 /* A subroutine of dead_or_predicable called through for_each_rtx.
3535 Return 1 if a memory is found. */
3538 find_memory (rtx *px, void *data ATTRIBUTE_UNUSED)
3543 /* Used by the code above to perform the actual rtl transformations.
3544 Return TRUE if successful.
3546 TEST_BB is the block containing the conditional branch. MERGE_BB
3547 is the block containing the code to manipulate. NEW_DEST is the
3548 label TEST_BB should be branching to after the conversion.
3549 REVERSEP is true if the sense of the branch should be reversed. */
3552 dead_or_predicable (basic_block test_bb, basic_block merge_bb,
3553 basic_block other_bb, basic_block new_dest, int reversep)
3555 rtx head, end, jump, earliest = NULL_RTX, old_dest, new_label = NULL_RTX;
3557 jump = BB_END (test_bb);
3559 /* Find the extent of the real code in the merge block. */
3560 head = BB_HEAD (merge_bb);
3561 end = BB_END (merge_bb);
3563 /* If merge_bb ends with a tablejump, predicating/moving insn's
3564 into test_bb and then deleting merge_bb will result in the jumptable
3565 that follows merge_bb being removed along with merge_bb and then we
3566 get an unresolved reference to the jumptable. */
3567 if (tablejump_p (end, NULL, NULL))
3571 head = NEXT_INSN (head);
3576 head = end = NULL_RTX;
3579 head = NEXT_INSN (head);
3586 head = end = NULL_RTX;
3589 end = PREV_INSN (end);
3592 /* Disable handling dead code by conditional execution if the machine needs
3593 to do anything funny with the tests, etc. */
3594 #ifndef IFCVT_MODIFY_TESTS
3595 if (HAVE_conditional_execution)
3597 /* In the conditional execution case, we have things easy. We know
3598 the condition is reversible. We don't have to check life info
3599 because we're going to conditionally execute the code anyway.
3600 All that's left is making sure the insns involved can actually
3605 cond = cond_exec_get_condition (jump);
3609 prob_val = find_reg_note (jump, REG_BR_PROB, NULL_RTX);
3611 prob_val = XEXP (prob_val, 0);
3615 enum rtx_code rev = reversed_comparison_code (cond, jump);
3618 cond = gen_rtx_fmt_ee (rev, GET_MODE (cond), XEXP (cond, 0),
3621 prob_val = GEN_INT (REG_BR_PROB_BASE - INTVAL (prob_val));
3624 if (! cond_exec_process_insns ((ce_if_block_t *)0, head, end, cond,
3633 /* In the non-conditional execution case, we have to verify that there
3634 are no trapping operations, no calls, no references to memory, and
3635 that any registers modified are dead at the branch site. */
3637 rtx insn, cond, prev;
3638 regset merge_set, tmp, test_live, test_set;
3639 struct propagate_block_info *pbi;
3640 unsigned i, fail = 0;
3643 /* Check for no calls or trapping operations. */
3644 for (insn = head; ; insn = NEXT_INSN (insn))
3650 if (may_trap_p (PATTERN (insn)))
3653 /* ??? Even non-trapping memories such as stack frame
3654 references must be avoided. For stores, we collect
3655 no lifetime info; for reads, we'd have to assert
3656 true_dependence false against every store in the
3658 if (for_each_rtx (&PATTERN (insn), find_memory, NULL))
3665 if (! any_condjump_p (jump))
3668 /* Find the extent of the conditional. */
3669 cond = noce_get_condition (jump, &earliest);
3674 MERGE_SET = set of registers set in MERGE_BB
3675 TEST_LIVE = set of registers live at EARLIEST
3676 TEST_SET = set of registers set between EARLIEST and the
3677 end of the block. */
3679 tmp = ALLOC_REG_SET (®_obstack);
3680 merge_set = ALLOC_REG_SET (®_obstack);
3681 test_live = ALLOC_REG_SET (®_obstack);
3682 test_set = ALLOC_REG_SET (®_obstack);
3684 /* ??? bb->local_set is only valid during calculate_global_regs_live,
3685 so we must recompute usage for MERGE_BB. Not so bad, I suppose,
3686 since we've already asserted that MERGE_BB is small. */
3687 /* If we allocated new pseudos (e.g. in the conditional move
3688 expander called from noce_emit_cmove), we must resize the
3690 if (max_regno < max_reg_num ())
3692 max_regno = max_reg_num ();
3693 allocate_reg_info (max_regno, FALSE, FALSE);
3695 propagate_block (merge_bb, tmp, merge_set, merge_set, 0);
3697 /* For small register class machines, don't lengthen lifetimes of
3698 hard registers before reload. */
3699 if (SMALL_REGISTER_CLASSES && ! reload_completed)
3701 EXECUTE_IF_SET_IN_BITMAP (merge_set, 0, i, bi)
3703 if (i < FIRST_PSEUDO_REGISTER
3705 && ! global_regs[i])
3710 /* For TEST, we're interested in a range of insns, not a whole block.
3711 Moreover, we're interested in the insns live from OTHER_BB. */
3713 COPY_REG_SET (test_live, other_bb->il.rtl->global_live_at_start);
3714 pbi = init_propagate_block_info (test_bb, test_live, test_set, test_set,
3717 for (insn = jump; ; insn = prev)
3719 prev = propagate_one_insn (pbi, insn);
3720 if (insn == earliest)
3724 free_propagate_block_info (pbi);
3726 /* We can perform the transformation if
3727 MERGE_SET & (TEST_SET | TEST_LIVE)
3729 TEST_SET & merge_bb->il.rtl->global_live_at_start
3732 if (bitmap_intersect_p (test_set, merge_set)
3733 || bitmap_intersect_p (test_live, merge_set)
3734 || bitmap_intersect_p (test_set,
3735 merge_bb->il.rtl->global_live_at_start))
3739 FREE_REG_SET (merge_set);
3740 FREE_REG_SET (test_live);
3741 FREE_REG_SET (test_set);
3748 /* We don't want to use normal invert_jump or redirect_jump because
3749 we don't want to delete_insn called. Also, we want to do our own
3750 change group management. */
3752 old_dest = JUMP_LABEL (jump);
3753 if (other_bb != new_dest)
3755 new_label = block_label (new_dest);
3757 ? ! invert_jump_1 (jump, new_label)
3758 : ! redirect_jump_1 (jump, new_label))
3762 if (! apply_change_group ())
3765 if (other_bb != new_dest)
3767 redirect_jump_2 (jump, old_dest, new_label, -1, reversep);
3769 redirect_edge_succ (BRANCH_EDGE (test_bb), new_dest);
3772 gcov_type count, probability;
3773 count = BRANCH_EDGE (test_bb)->count;
3774 BRANCH_EDGE (test_bb)->count = FALLTHRU_EDGE (test_bb)->count;
3775 FALLTHRU_EDGE (test_bb)->count = count;
3776 probability = BRANCH_EDGE (test_bb)->probability;
3777 BRANCH_EDGE (test_bb)->probability
3778 = FALLTHRU_EDGE (test_bb)->probability;
3779 FALLTHRU_EDGE (test_bb)->probability = probability;
3780 update_br_prob_note (test_bb);
3784 /* Move the insns out of MERGE_BB to before the branch. */
3789 if (end == BB_END (merge_bb))
3790 BB_END (merge_bb) = PREV_INSN (head);
3792 if (squeeze_notes (&head, &end))
3795 /* PR 21767: When moving insns above a conditional branch, REG_EQUAL
3796 notes might become invalid. */
3802 if (! INSN_P (insn))
3804 note = find_reg_note (insn, REG_EQUAL, NULL_RTX);
3807 set = single_set (insn);
3808 if (!set || !function_invariant_p (SET_SRC (set)))
3809 remove_note (insn, note);
3810 } while (insn != end && (insn = NEXT_INSN (insn)));
3812 reorder_insns (head, end, PREV_INSN (earliest));
3815 /* Remove the jump and edge if we can. */
3816 if (other_bb == new_dest)
3819 remove_edge (BRANCH_EDGE (test_bb));
3820 /* ??? Can't merge blocks here, as then_bb is still in use.
3821 At minimum, the merge will get done just before bb-reorder. */
3831 /* Main entry point for all if-conversion. */
3834 if_convert (int x_life_data_ok)
3839 num_possible_if_blocks = 0;
3840 num_updated_if_blocks = 0;
3841 num_true_changes = 0;
3842 life_data_ok = (x_life_data_ok != 0);
3844 if ((! targetm.cannot_modify_jumps_p ())
3845 && (!flag_reorder_blocks_and_partition || !no_new_pseudos
3846 || !targetm.have_named_sections))
3850 flow_loops_find (&loops);
3851 mark_loop_exit_edges (&loops);
3852 flow_loops_free (&loops);
3853 free_dominance_info (CDI_DOMINATORS);
3856 /* Compute postdominators if we think we'll use them. */
3857 if (HAVE_conditional_execution || life_data_ok)
3858 calculate_dominance_info (CDI_POST_DOMINATORS);
3863 /* Go through each of the basic blocks looking for things to convert. If we
3864 have conditional execution, we make multiple passes to allow us to handle
3865 IF-THEN{-ELSE} blocks within other IF-THEN{-ELSE} blocks. */
3869 cond_exec_changed_p = FALSE;
3872 #ifdef IFCVT_MULTIPLE_DUMPS
3873 if (dump_file && pass > 1)
3874 fprintf (dump_file, "\n\n========== Pass %d ==========\n", pass);
3880 while ((new_bb = find_if_header (bb, pass)))
3884 #ifdef IFCVT_MULTIPLE_DUMPS
3885 if (dump_file && cond_exec_changed_p)
3886 print_rtl_with_bb (dump_file, get_insns ());
3889 while (cond_exec_changed_p);
3891 #ifdef IFCVT_MULTIPLE_DUMPS
3893 fprintf (dump_file, "\n\n========== no more changes\n");
3896 free_dominance_info (CDI_POST_DOMINATORS);
3901 clear_aux_for_blocks ();
3903 /* Rebuild life info for basic blocks that require it. */
3904 if (num_true_changes && life_data_ok)
3906 /* If we allocated new pseudos, we must resize the array for sched1. */
3907 if (max_regno < max_reg_num ())
3909 max_regno = max_reg_num ();
3910 allocate_reg_info (max_regno, FALSE, FALSE);
3912 update_life_info_in_dirty_blocks (UPDATE_LIFE_GLOBAL_RM_NOTES,
3913 PROP_DEATH_NOTES | PROP_SCAN_DEAD_CODE
3914 | PROP_KILL_DEAD_CODE);
3917 /* Write the final stats. */
3918 if (dump_file && num_possible_if_blocks > 0)
3921 "\n%d possible IF blocks searched.\n",
3922 num_possible_if_blocks);
3924 "%d IF blocks converted.\n",
3925 num_updated_if_blocks);
3927 "%d true changes made.\n\n\n",
3931 #ifdef ENABLE_CHECKING
3932 verify_flow_info ();
3937 gate_handle_if_conversion (void)
3939 return (optimize > 0);
3942 /* If-conversion and CFG cleanup. */
3944 rest_of_handle_if_conversion (void)
3946 if (flag_if_conversion)
3949 dump_flow_info (dump_file, dump_flags);
3950 cleanup_cfg (CLEANUP_EXPENSIVE);
3951 reg_scan (get_insns (), max_reg_num ());
3955 timevar_push (TV_JUMP);
3956 cleanup_cfg (CLEANUP_EXPENSIVE);
3957 reg_scan (get_insns (), max_reg_num ());
3958 timevar_pop (TV_JUMP);
3962 struct tree_opt_pass pass_rtl_ifcvt =
3965 gate_handle_if_conversion, /* gate */
3966 rest_of_handle_if_conversion, /* execute */
3969 0, /* static_pass_number */
3970 TV_IFCVT, /* tv_id */
3971 0, /* properties_required */
3972 0, /* properties_provided */
3973 0, /* properties_destroyed */
3974 0, /* todo_flags_start */
3975 TODO_dump_func, /* todo_flags_finish */
3980 gate_handle_if_after_combine (void)
3982 return (optimize > 0 && flag_if_conversion);
3986 /* Rerun if-conversion, as combine may have simplified things enough
3987 to now meet sequence length restrictions. */
3989 rest_of_handle_if_after_combine (void)
3997 struct tree_opt_pass pass_if_after_combine =
4000 gate_handle_if_after_combine, /* gate */
4001 rest_of_handle_if_after_combine, /* execute */
4004 0, /* static_pass_number */
4005 TV_IFCVT, /* tv_id */
4006 0, /* properties_required */
4007 0, /* properties_provided */
4008 0, /* properties_destroyed */
4009 0, /* todo_flags_start */
4011 TODO_ggc_collect, /* todo_flags_finish */
4017 gate_handle_if_after_reload (void)
4019 return (optimize > 0);
4023 rest_of_handle_if_after_reload (void)
4025 /* Last attempt to optimize CFG, as scheduling, peepholing and insn
4026 splitting possibly introduced more crossjumping opportunities. */
4027 cleanup_cfg (CLEANUP_EXPENSIVE
4028 | CLEANUP_UPDATE_LIFE
4029 | (flag_crossjumping ? CLEANUP_CROSSJUMP : 0));
4030 if (flag_if_conversion2)
4036 struct tree_opt_pass pass_if_after_reload =
4039 gate_handle_if_after_reload, /* gate */
4040 rest_of_handle_if_after_reload, /* execute */
4043 0, /* static_pass_number */
4044 TV_IFCVT2, /* tv_id */
4045 0, /* properties_required */
4046 0, /* properties_provided */
4047 0, /* properties_destroyed */
4048 0, /* todo_flags_start */
4050 TODO_ggc_collect, /* todo_flags_finish */