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. */
599 /* A basic block that ends in a simple conditional jump. */
602 /* The jump that ends TEST_BB. */
605 /* The jump condition. */
608 /* New insns should be inserted before this one. */
611 /* Insns in the THEN and ELSE block. There is always just this
612 one insns in those blocks. The insns are single_set insns.
613 If there was no ELSE block, INSN_B is the last insn before
614 COND_EARLIEST, or NULL_RTX. In the former case, the insn
615 operands are still valid, as if INSN_B was moved down below
619 /* The SET_SRC of INSN_A and INSN_B. */
622 /* The SET_DEST of INSN_A. */
626 static rtx noce_emit_store_flag (struct noce_if_info *, rtx, int, int);
627 static int noce_try_move (struct noce_if_info *);
628 static int noce_try_store_flag (struct noce_if_info *);
629 static int noce_try_addcc (struct noce_if_info *);
630 static int noce_try_store_flag_constants (struct noce_if_info *);
631 static int noce_try_store_flag_mask (struct noce_if_info *);
632 static rtx noce_emit_cmove (struct noce_if_info *, rtx, enum rtx_code, rtx,
634 static int noce_try_cmove (struct noce_if_info *);
635 static int noce_try_cmove_arith (struct noce_if_info *);
636 static rtx noce_get_alt_condition (struct noce_if_info *, rtx, rtx *);
637 static int noce_try_minmax (struct noce_if_info *);
638 static int noce_try_abs (struct noce_if_info *);
639 static int noce_try_sign_mask (struct noce_if_info *);
641 /* Helper function for noce_try_store_flag*. */
644 noce_emit_store_flag (struct noce_if_info *if_info, rtx x, int reversep,
647 rtx cond = if_info->cond;
651 cond_complex = (! general_operand (XEXP (cond, 0), VOIDmode)
652 || ! general_operand (XEXP (cond, 1), VOIDmode));
654 /* If earliest == jump, or when the condition is complex, try to
655 build the store_flag insn directly. */
658 cond = XEXP (SET_SRC (pc_set (if_info->jump)), 0);
661 code = reversed_comparison_code (cond, if_info->jump);
663 code = GET_CODE (cond);
665 if ((if_info->cond_earliest == if_info->jump || cond_complex)
666 && (normalize == 0 || STORE_FLAG_VALUE == normalize))
670 tmp = gen_rtx_fmt_ee (code, GET_MODE (x), XEXP (cond, 0),
672 tmp = gen_rtx_SET (VOIDmode, x, tmp);
675 tmp = emit_insn (tmp);
677 if (recog_memoized (tmp) >= 0)
683 if_info->cond_earliest = if_info->jump;
691 /* Don't even try if the comparison operands or the mode of X are weird. */
692 if (cond_complex || !SCALAR_INT_MODE_P (GET_MODE (x)))
695 return emit_store_flag (x, code, XEXP (cond, 0),
696 XEXP (cond, 1), VOIDmode,
697 (code == LTU || code == LEU
698 || code == GEU || code == GTU), normalize);
701 /* Emit instruction to move an rtx, possibly into STRICT_LOW_PART.
702 X is the destination/target and Y is the value to copy. */
705 noce_emit_move_insn (rtx x, rtx y)
707 enum machine_mode outmode;
711 if (GET_CODE (x) != STRICT_LOW_PART)
713 rtx seq, insn, target;
717 /* Check that the SET_SRC is reasonable before calling emit_move_insn,
718 otherwise construct a suitable SET pattern ourselves. */
719 insn = (OBJECT_P (y) || CONSTANT_P (y) || GET_CODE (y) == SUBREG)
720 ? emit_move_insn (x, y)
721 : emit_insn (gen_rtx_SET (VOIDmode, x, y));
725 if (recog_memoized (insn) <= 0)
727 if (GET_CODE (x) == ZERO_EXTRACT)
729 rtx op = XEXP (x, 0);
730 unsigned HOST_WIDE_INT size = INTVAL (XEXP (x, 1));
731 unsigned HOST_WIDE_INT start = INTVAL (XEXP (x, 2));
733 /* store_bit_field expects START to be relative to
734 BYTES_BIG_ENDIAN and adjusts this value for machines with
735 BITS_BIG_ENDIAN != BYTES_BIG_ENDIAN. In order to be able to
736 invoke store_bit_field again it is necessary to have the START
737 value from the first call. */
738 if (BITS_BIG_ENDIAN != BYTES_BIG_ENDIAN)
741 start = BITS_PER_UNIT - start - size;
744 gcc_assert (REG_P (op));
745 start = BITS_PER_WORD - start - size;
749 gcc_assert (start < (MEM_P (op) ? BITS_PER_UNIT : BITS_PER_WORD));
750 store_bit_field (op, size, start, GET_MODE (x), y);
754 switch (GET_RTX_CLASS (GET_CODE (y)))
757 ot = code_to_optab[GET_CODE (y)];
761 target = expand_unop (GET_MODE (y), ot, XEXP (y, 0), x, 0);
762 if (target != NULL_RTX)
765 emit_move_insn (x, target);
774 ot = code_to_optab[GET_CODE (y)];
778 target = expand_binop (GET_MODE (y), ot,
779 XEXP (y, 0), XEXP (y, 1),
781 if (target != NULL_RTX)
784 emit_move_insn (x, target);
801 inner = XEXP (outer, 0);
802 outmode = GET_MODE (outer);
803 bitpos = SUBREG_BYTE (outer) * BITS_PER_UNIT;
804 store_bit_field (inner, GET_MODE_BITSIZE (outmode), bitpos, outmode, y);
807 /* Return sequence of instructions generated by if conversion. This
808 function calls end_sequence() to end the current stream, ensures
809 that are instructions are unshared, recognizable non-jump insns.
810 On failure, this function returns a NULL_RTX. */
813 end_ifcvt_sequence (struct noce_if_info *if_info)
816 rtx seq = get_insns ();
818 set_used_flags (if_info->x);
819 set_used_flags (if_info->cond);
820 unshare_all_rtl_in_chain (seq);
823 /* Make sure that all of the instructions emitted are recognizable,
824 and that we haven't introduced a new jump instruction.
825 As an exercise for the reader, build a general mechanism that
826 allows proper placement of required clobbers. */
827 for (insn = seq; insn; insn = NEXT_INSN (insn))
829 || recog_memoized (insn) == -1)
835 /* Convert "if (a != b) x = a; else x = b" into "x = a" and
836 "if (a == b) x = a; else x = b" into "x = b". */
839 noce_try_move (struct noce_if_info *if_info)
841 rtx cond = if_info->cond;
842 enum rtx_code code = GET_CODE (cond);
845 if (code != NE && code != EQ)
848 /* This optimization isn't valid if either A or B could be a NaN
850 if (HONOR_NANS (GET_MODE (if_info->x))
851 || HONOR_SIGNED_ZEROS (GET_MODE (if_info->x)))
854 /* Check whether the operands of the comparison are A and in
856 if ((rtx_equal_p (if_info->a, XEXP (cond, 0))
857 && rtx_equal_p (if_info->b, XEXP (cond, 1)))
858 || (rtx_equal_p (if_info->a, XEXP (cond, 1))
859 && rtx_equal_p (if_info->b, XEXP (cond, 0))))
861 y = (code == EQ) ? if_info->a : if_info->b;
863 /* Avoid generating the move if the source is the destination. */
864 if (! rtx_equal_p (if_info->x, y))
867 noce_emit_move_insn (if_info->x, y);
868 seq = end_ifcvt_sequence (if_info);
872 emit_insn_before_setloc (seq, if_info->jump,
873 INSN_LOCATOR (if_info->insn_a));
880 /* Convert "if (test) x = 1; else x = 0".
882 Only try 0 and STORE_FLAG_VALUE here. Other combinations will be
883 tried in noce_try_store_flag_constants after noce_try_cmove has had
884 a go at the conversion. */
887 noce_try_store_flag (struct noce_if_info *if_info)
892 if (GET_CODE (if_info->b) == CONST_INT
893 && INTVAL (if_info->b) == STORE_FLAG_VALUE
894 && if_info->a == const0_rtx)
896 else if (if_info->b == const0_rtx
897 && GET_CODE (if_info->a) == CONST_INT
898 && INTVAL (if_info->a) == STORE_FLAG_VALUE
899 && (reversed_comparison_code (if_info->cond, if_info->jump)
907 target = noce_emit_store_flag (if_info, if_info->x, reversep, 0);
910 if (target != if_info->x)
911 noce_emit_move_insn (if_info->x, target);
913 seq = end_ifcvt_sequence (if_info);
917 emit_insn_before_setloc (seq, if_info->jump,
918 INSN_LOCATOR (if_info->insn_a));
928 /* Convert "if (test) x = a; else x = b", for A and B constant. */
931 noce_try_store_flag_constants (struct noce_if_info *if_info)
935 HOST_WIDE_INT itrue, ifalse, diff, tmp;
936 int normalize, can_reverse;
937 enum machine_mode mode;
940 && GET_CODE (if_info->a) == CONST_INT
941 && GET_CODE (if_info->b) == CONST_INT)
943 mode = GET_MODE (if_info->x);
944 ifalse = INTVAL (if_info->a);
945 itrue = INTVAL (if_info->b);
947 /* Make sure we can represent the difference between the two values. */
948 if ((itrue - ifalse > 0)
949 != ((ifalse < 0) != (itrue < 0) ? ifalse < 0 : ifalse < itrue))
952 diff = trunc_int_for_mode (itrue - ifalse, mode);
954 can_reverse = (reversed_comparison_code (if_info->cond, if_info->jump)
958 if (diff == STORE_FLAG_VALUE || diff == -STORE_FLAG_VALUE)
960 else if (ifalse == 0 && exact_log2 (itrue) >= 0
961 && (STORE_FLAG_VALUE == 1
962 || BRANCH_COST >= 2))
964 else if (itrue == 0 && exact_log2 (ifalse) >= 0 && can_reverse
965 && (STORE_FLAG_VALUE == 1 || BRANCH_COST >= 2))
966 normalize = 1, reversep = 1;
968 && (STORE_FLAG_VALUE == -1
969 || BRANCH_COST >= 2))
971 else if (ifalse == -1 && can_reverse
972 && (STORE_FLAG_VALUE == -1 || BRANCH_COST >= 2))
973 normalize = -1, reversep = 1;
974 else if ((BRANCH_COST >= 2 && STORE_FLAG_VALUE == -1)
982 tmp = itrue; itrue = ifalse; ifalse = tmp;
983 diff = trunc_int_for_mode (-diff, mode);
987 target = noce_emit_store_flag (if_info, if_info->x, reversep, normalize);
994 /* if (test) x = 3; else x = 4;
995 => x = 3 + (test == 0); */
996 if (diff == STORE_FLAG_VALUE || diff == -STORE_FLAG_VALUE)
998 target = expand_simple_binop (mode,
999 (diff == STORE_FLAG_VALUE
1001 GEN_INT (ifalse), target, if_info->x, 0,
1005 /* if (test) x = 8; else x = 0;
1006 => x = (test != 0) << 3; */
1007 else if (ifalse == 0 && (tmp = exact_log2 (itrue)) >= 0)
1009 target = expand_simple_binop (mode, ASHIFT,
1010 target, GEN_INT (tmp), if_info->x, 0,
1014 /* if (test) x = -1; else x = b;
1015 => x = -(test != 0) | b; */
1016 else if (itrue == -1)
1018 target = expand_simple_binop (mode, IOR,
1019 target, GEN_INT (ifalse), if_info->x, 0,
1023 /* if (test) x = a; else x = b;
1024 => x = (-(test != 0) & (b - a)) + a; */
1027 target = expand_simple_binop (mode, AND,
1028 target, GEN_INT (diff), if_info->x, 0,
1031 target = expand_simple_binop (mode, PLUS,
1032 target, GEN_INT (ifalse),
1033 if_info->x, 0, OPTAB_WIDEN);
1042 if (target != if_info->x)
1043 noce_emit_move_insn (if_info->x, target);
1045 seq = end_ifcvt_sequence (if_info);
1049 emit_insn_before_setloc (seq, if_info->jump,
1050 INSN_LOCATOR (if_info->insn_a));
1057 /* Convert "if (test) foo++" into "foo += (test != 0)", and
1058 similarly for "foo--". */
1061 noce_try_addcc (struct noce_if_info *if_info)
1064 int subtract, normalize;
1066 if (! no_new_pseudos
1067 && GET_CODE (if_info->a) == PLUS
1068 && rtx_equal_p (XEXP (if_info->a, 0), if_info->b)
1069 && (reversed_comparison_code (if_info->cond, if_info->jump)
1072 rtx cond = if_info->cond;
1073 enum rtx_code code = reversed_comparison_code (cond, if_info->jump);
1075 /* First try to use addcc pattern. */
1076 if (general_operand (XEXP (cond, 0), VOIDmode)
1077 && general_operand (XEXP (cond, 1), VOIDmode))
1080 target = emit_conditional_add (if_info->x, code,
1085 XEXP (if_info->a, 1),
1086 GET_MODE (if_info->x),
1087 (code == LTU || code == GEU
1088 || code == LEU || code == GTU));
1091 if (target != if_info->x)
1092 noce_emit_move_insn (if_info->x, target);
1094 seq = end_ifcvt_sequence (if_info);
1098 emit_insn_before_setloc (seq, if_info->jump,
1099 INSN_LOCATOR (if_info->insn_a));
1105 /* If that fails, construct conditional increment or decrement using
1107 if (BRANCH_COST >= 2
1108 && (XEXP (if_info->a, 1) == const1_rtx
1109 || XEXP (if_info->a, 1) == constm1_rtx))
1112 if (STORE_FLAG_VALUE == INTVAL (XEXP (if_info->a, 1)))
1113 subtract = 0, normalize = 0;
1114 else if (-STORE_FLAG_VALUE == INTVAL (XEXP (if_info->a, 1)))
1115 subtract = 1, normalize = 0;
1117 subtract = 0, normalize = INTVAL (XEXP (if_info->a, 1));
1120 target = noce_emit_store_flag (if_info,
1121 gen_reg_rtx (GET_MODE (if_info->x)),
1125 target = expand_simple_binop (GET_MODE (if_info->x),
1126 subtract ? MINUS : PLUS,
1127 if_info->b, target, if_info->x,
1131 if (target != if_info->x)
1132 noce_emit_move_insn (if_info->x, target);
1134 seq = end_ifcvt_sequence (if_info);
1138 emit_insn_before_setloc (seq, if_info->jump,
1139 INSN_LOCATOR (if_info->insn_a));
1149 /* Convert "if (test) x = 0;" to "x &= -(test == 0);" */
1152 noce_try_store_flag_mask (struct noce_if_info *if_info)
1158 if (! no_new_pseudos
1159 && (BRANCH_COST >= 2
1160 || STORE_FLAG_VALUE == -1)
1161 && ((if_info->a == const0_rtx
1162 && rtx_equal_p (if_info->b, if_info->x))
1163 || ((reversep = (reversed_comparison_code (if_info->cond,
1166 && if_info->b == const0_rtx
1167 && rtx_equal_p (if_info->a, if_info->x))))
1170 target = noce_emit_store_flag (if_info,
1171 gen_reg_rtx (GET_MODE (if_info->x)),
1174 target = expand_simple_binop (GET_MODE (if_info->x), AND,
1176 target, if_info->x, 0,
1181 if (target != if_info->x)
1182 noce_emit_move_insn (if_info->x, target);
1184 seq = end_ifcvt_sequence (if_info);
1188 emit_insn_before_setloc (seq, if_info->jump,
1189 INSN_LOCATOR (if_info->insn_a));
1199 /* Helper function for noce_try_cmove and noce_try_cmove_arith. */
1202 noce_emit_cmove (struct noce_if_info *if_info, rtx x, enum rtx_code code,
1203 rtx cmp_a, rtx cmp_b, rtx vfalse, rtx vtrue)
1205 /* If earliest == jump, try to build the cmove insn directly.
1206 This is helpful when combine has created some complex condition
1207 (like for alpha's cmovlbs) that we can't hope to regenerate
1208 through the normal interface. */
1210 if (if_info->cond_earliest == if_info->jump)
1214 tmp = gen_rtx_fmt_ee (code, GET_MODE (if_info->cond), cmp_a, cmp_b);
1215 tmp = gen_rtx_IF_THEN_ELSE (GET_MODE (x), tmp, vtrue, vfalse);
1216 tmp = gen_rtx_SET (VOIDmode, x, tmp);
1219 tmp = emit_insn (tmp);
1221 if (recog_memoized (tmp) >= 0)
1233 /* Don't even try if the comparison operands are weird. */
1234 if (! general_operand (cmp_a, GET_MODE (cmp_a))
1235 || ! general_operand (cmp_b, GET_MODE (cmp_b)))
1238 #if HAVE_conditional_move
1239 return emit_conditional_move (x, code, cmp_a, cmp_b, VOIDmode,
1240 vtrue, vfalse, GET_MODE (x),
1241 (code == LTU || code == GEU
1242 || code == LEU || code == GTU));
1244 /* We'll never get here, as noce_process_if_block doesn't call the
1245 functions involved. Ifdef code, however, should be discouraged
1246 because it leads to typos in the code not selected. However,
1247 emit_conditional_move won't exist either. */
1252 /* Try only simple constants and registers here. More complex cases
1253 are handled in noce_try_cmove_arith after noce_try_store_flag_arith
1254 has had a go at it. */
1257 noce_try_cmove (struct noce_if_info *if_info)
1262 if ((CONSTANT_P (if_info->a) || register_operand (if_info->a, VOIDmode))
1263 && (CONSTANT_P (if_info->b) || register_operand (if_info->b, VOIDmode)))
1267 code = GET_CODE (if_info->cond);
1268 target = noce_emit_cmove (if_info, if_info->x, code,
1269 XEXP (if_info->cond, 0),
1270 XEXP (if_info->cond, 1),
1271 if_info->a, if_info->b);
1275 if (target != if_info->x)
1276 noce_emit_move_insn (if_info->x, target);
1278 seq = end_ifcvt_sequence (if_info);
1282 emit_insn_before_setloc (seq, if_info->jump,
1283 INSN_LOCATOR (if_info->insn_a));
1296 /* Try more complex cases involving conditional_move. */
1299 noce_try_cmove_arith (struct noce_if_info *if_info)
1311 /* A conditional move from two memory sources is equivalent to a
1312 conditional on their addresses followed by a load. Don't do this
1313 early because it'll screw alias analysis. Note that we've
1314 already checked for no side effects. */
1315 if (! no_new_pseudos && cse_not_expected
1316 && MEM_P (a) && MEM_P (b)
1317 && BRANCH_COST >= 5)
1321 x = gen_reg_rtx (Pmode);
1325 /* ??? We could handle this if we knew that a load from A or B could
1326 not fault. This is also true if we've already loaded
1327 from the address along the path from ENTRY. */
1328 else if (may_trap_p (a) || may_trap_p (b))
1331 /* if (test) x = a + b; else x = c - d;
1338 code = GET_CODE (if_info->cond);
1339 insn_a = if_info->insn_a;
1340 insn_b = if_info->insn_b;
1342 /* Total insn_rtx_cost should be smaller than branch cost. Exit
1343 if insn_rtx_cost can't be estimated. */
1346 insn_cost = insn_rtx_cost (PATTERN (insn_a));
1347 if (insn_cost == 0 || insn_cost > COSTS_N_INSNS (BRANCH_COST))
1355 insn_cost += insn_rtx_cost (PATTERN (insn_b));
1356 if (insn_cost == 0 || insn_cost > COSTS_N_INSNS (BRANCH_COST))
1360 /* Possibly rearrange operands to make things come out more natural. */
1361 if (reversed_comparison_code (if_info->cond, if_info->jump) != UNKNOWN)
1364 if (rtx_equal_p (b, x))
1366 else if (general_operand (b, GET_MODE (b)))
1371 code = reversed_comparison_code (if_info->cond, if_info->jump);
1372 tmp = a, a = b, b = tmp;
1373 tmp = insn_a, insn_a = insn_b, insn_b = tmp;
1382 /* If either operand is complex, load it into a register first.
1383 The best way to do this is to copy the original insn. In this
1384 way we preserve any clobbers etc that the insn may have had.
1385 This is of course not possible in the IS_MEM case. */
1386 if (! general_operand (a, GET_MODE (a)))
1391 goto end_seq_and_fail;
1395 tmp = gen_reg_rtx (GET_MODE (a));
1396 tmp = emit_insn (gen_rtx_SET (VOIDmode, tmp, a));
1399 goto end_seq_and_fail;
1402 a = gen_reg_rtx (GET_MODE (a));
1403 tmp = copy_rtx (insn_a);
1404 set = single_set (tmp);
1406 tmp = emit_insn (PATTERN (tmp));
1408 if (recog_memoized (tmp) < 0)
1409 goto end_seq_and_fail;
1411 if (! general_operand (b, GET_MODE (b)))
1416 goto end_seq_and_fail;
1420 tmp = gen_reg_rtx (GET_MODE (b));
1421 tmp = gen_rtx_SET (VOIDmode, tmp, b);
1424 goto end_seq_and_fail;
1427 b = gen_reg_rtx (GET_MODE (b));
1428 tmp = copy_rtx (insn_b);
1429 set = single_set (tmp);
1431 tmp = PATTERN (tmp);
1434 /* If insn to set up A clobbers any registers B depends on, try to
1435 swap insn that sets up A with the one that sets up B. If even
1436 that doesn't help, punt. */
1437 last = get_last_insn ();
1438 if (last && modified_in_p (orig_b, last))
1440 tmp = emit_insn_before (tmp, get_insns ());
1441 if (modified_in_p (orig_a, tmp))
1442 goto end_seq_and_fail;
1445 tmp = emit_insn (tmp);
1447 if (recog_memoized (tmp) < 0)
1448 goto end_seq_and_fail;
1451 target = noce_emit_cmove (if_info, x, code, XEXP (if_info->cond, 0),
1452 XEXP (if_info->cond, 1), a, b);
1455 goto end_seq_and_fail;
1457 /* If we're handling a memory for above, emit the load now. */
1460 tmp = gen_rtx_MEM (GET_MODE (if_info->x), target);
1462 /* Copy over flags as appropriate. */
1463 if (MEM_VOLATILE_P (if_info->a) || MEM_VOLATILE_P (if_info->b))
1464 MEM_VOLATILE_P (tmp) = 1;
1465 if (MEM_IN_STRUCT_P (if_info->a) && MEM_IN_STRUCT_P (if_info->b))
1466 MEM_IN_STRUCT_P (tmp) = 1;
1467 if (MEM_SCALAR_P (if_info->a) && MEM_SCALAR_P (if_info->b))
1468 MEM_SCALAR_P (tmp) = 1;
1469 if (MEM_ALIAS_SET (if_info->a) == MEM_ALIAS_SET (if_info->b))
1470 set_mem_alias_set (tmp, MEM_ALIAS_SET (if_info->a));
1472 MIN (MEM_ALIGN (if_info->a), MEM_ALIGN (if_info->b)));
1474 noce_emit_move_insn (if_info->x, tmp);
1476 else if (target != x)
1477 noce_emit_move_insn (x, target);
1479 tmp = end_ifcvt_sequence (if_info);
1483 emit_insn_before_setloc (tmp, if_info->jump, INSN_LOCATOR (if_info->insn_a));
1491 /* For most cases, the simplified condition we found is the best
1492 choice, but this is not the case for the min/max/abs transforms.
1493 For these we wish to know that it is A or B in the condition. */
1496 noce_get_alt_condition (struct noce_if_info *if_info, rtx target,
1499 rtx cond, set, insn;
1502 /* If target is already mentioned in the known condition, return it. */
1503 if (reg_mentioned_p (target, if_info->cond))
1505 *earliest = if_info->cond_earliest;
1506 return if_info->cond;
1509 set = pc_set (if_info->jump);
1510 cond = XEXP (SET_SRC (set), 0);
1512 = GET_CODE (XEXP (SET_SRC (set), 2)) == LABEL_REF
1513 && XEXP (XEXP (SET_SRC (set), 2), 0) == JUMP_LABEL (if_info->jump);
1515 /* If we're looking for a constant, try to make the conditional
1516 have that constant in it. There are two reasons why it may
1517 not have the constant we want:
1519 1. GCC may have needed to put the constant in a register, because
1520 the target can't compare directly against that constant. For
1521 this case, we look for a SET immediately before the comparison
1522 that puts a constant in that register.
1524 2. GCC may have canonicalized the conditional, for example
1525 replacing "if x < 4" with "if x <= 3". We can undo that (or
1526 make equivalent types of changes) to get the constants we need
1527 if they're off by one in the right direction. */
1529 if (GET_CODE (target) == CONST_INT)
1531 enum rtx_code code = GET_CODE (if_info->cond);
1532 rtx op_a = XEXP (if_info->cond, 0);
1533 rtx op_b = XEXP (if_info->cond, 1);
1536 /* First, look to see if we put a constant in a register. */
1537 prev_insn = prev_nonnote_insn (if_info->cond_earliest);
1539 && INSN_P (prev_insn)
1540 && GET_CODE (PATTERN (prev_insn)) == SET)
1542 rtx src = find_reg_equal_equiv_note (prev_insn);
1544 src = SET_SRC (PATTERN (prev_insn));
1545 if (GET_CODE (src) == CONST_INT)
1547 if (rtx_equal_p (op_a, SET_DEST (PATTERN (prev_insn))))
1549 else if (rtx_equal_p (op_b, SET_DEST (PATTERN (prev_insn))))
1552 if (GET_CODE (op_a) == CONST_INT)
1557 code = swap_condition (code);
1562 /* Now, look to see if we can get the right constant by
1563 adjusting the conditional. */
1564 if (GET_CODE (op_b) == CONST_INT)
1566 HOST_WIDE_INT desired_val = INTVAL (target);
1567 HOST_WIDE_INT actual_val = INTVAL (op_b);
1572 if (actual_val == desired_val + 1)
1575 op_b = GEN_INT (desired_val);
1579 if (actual_val == desired_val - 1)
1582 op_b = GEN_INT (desired_val);
1586 if (actual_val == desired_val - 1)
1589 op_b = GEN_INT (desired_val);
1593 if (actual_val == desired_val + 1)
1596 op_b = GEN_INT (desired_val);
1604 /* If we made any changes, generate a new conditional that is
1605 equivalent to what we started with, but has the right
1607 if (code != GET_CODE (if_info->cond)
1608 || op_a != XEXP (if_info->cond, 0)
1609 || op_b != XEXP (if_info->cond, 1))
1611 cond = gen_rtx_fmt_ee (code, GET_MODE (cond), op_a, op_b);
1612 *earliest = if_info->cond_earliest;
1617 cond = canonicalize_condition (if_info->jump, cond, reverse,
1618 earliest, target, false, true);
1619 if (! cond || ! reg_mentioned_p (target, cond))
1622 /* We almost certainly searched back to a different place.
1623 Need to re-verify correct lifetimes. */
1625 /* X may not be mentioned in the range (cond_earliest, jump]. */
1626 for (insn = if_info->jump; insn != *earliest; insn = PREV_INSN (insn))
1627 if (INSN_P (insn) && reg_overlap_mentioned_p (if_info->x, PATTERN (insn)))
1630 /* A and B may not be modified in the range [cond_earliest, jump). */
1631 for (insn = *earliest; insn != if_info->jump; insn = NEXT_INSN (insn))
1633 && (modified_in_p (if_info->a, insn)
1634 || modified_in_p (if_info->b, insn)))
1640 /* Convert "if (a < b) x = a; else x = b;" to "x = min(a, b);", etc. */
1643 noce_try_minmax (struct noce_if_info *if_info)
1645 rtx cond, earliest, target, seq;
1646 enum rtx_code code, op;
1649 /* ??? Can't guarantee that expand_binop won't create pseudos. */
1653 /* ??? Reject modes with NaNs or signed zeros since we don't know how
1654 they will be resolved with an SMIN/SMAX. It wouldn't be too hard
1655 to get the target to tell us... */
1656 if (HONOR_SIGNED_ZEROS (GET_MODE (if_info->x))
1657 || HONOR_NANS (GET_MODE (if_info->x)))
1660 cond = noce_get_alt_condition (if_info, if_info->a, &earliest);
1664 /* Verify the condition is of the form we expect, and canonicalize
1665 the comparison code. */
1666 code = GET_CODE (cond);
1667 if (rtx_equal_p (XEXP (cond, 0), if_info->a))
1669 if (! rtx_equal_p (XEXP (cond, 1), if_info->b))
1672 else if (rtx_equal_p (XEXP (cond, 1), if_info->a))
1674 if (! rtx_equal_p (XEXP (cond, 0), if_info->b))
1676 code = swap_condition (code);
1681 /* Determine what sort of operation this is. Note that the code is for
1682 a taken branch, so the code->operation mapping appears backwards. */
1715 target = expand_simple_binop (GET_MODE (if_info->x), op,
1716 if_info->a, if_info->b,
1717 if_info->x, unsignedp, OPTAB_WIDEN);
1723 if (target != if_info->x)
1724 noce_emit_move_insn (if_info->x, target);
1726 seq = end_ifcvt_sequence (if_info);
1730 emit_insn_before_setloc (seq, if_info->jump, INSN_LOCATOR (if_info->insn_a));
1731 if_info->cond = cond;
1732 if_info->cond_earliest = earliest;
1737 /* Convert "if (a < 0) x = -a; else x = a;" to "x = abs(a);", etc. */
1740 noce_try_abs (struct noce_if_info *if_info)
1742 rtx cond, earliest, target, seq, a, b, c;
1745 /* ??? Can't guarantee that expand_binop won't create pseudos. */
1749 /* Recognize A and B as constituting an ABS or NABS. The canonical
1750 form is a branch around the negation, taken when the object is the
1751 first operand of a comparison against 0 that evaluates to true. */
1754 if (GET_CODE (a) == NEG && rtx_equal_p (XEXP (a, 0), b))
1756 else if (GET_CODE (b) == NEG && rtx_equal_p (XEXP (b, 0), a))
1758 c = a; a = b; b = c;
1764 cond = noce_get_alt_condition (if_info, b, &earliest);
1768 /* Verify the condition is of the form we expect. */
1769 if (rtx_equal_p (XEXP (cond, 0), b))
1771 else if (rtx_equal_p (XEXP (cond, 1), b))
1779 /* Verify that C is zero. Search one step backward for a
1780 REG_EQUAL note or a simple source if necessary. */
1783 rtx set, insn = prev_nonnote_insn (earliest);
1785 && (set = single_set (insn))
1786 && rtx_equal_p (SET_DEST (set), c))
1788 rtx note = find_reg_equal_equiv_note (insn);
1798 && GET_CODE (XEXP (c, 0)) == SYMBOL_REF
1799 && CONSTANT_POOL_ADDRESS_P (XEXP (c, 0)))
1800 c = get_pool_constant (XEXP (c, 0));
1802 /* Work around funny ideas get_condition has wrt canonicalization.
1803 Note that these rtx constants are known to be CONST_INT, and
1804 therefore imply integer comparisons. */
1805 if (c == constm1_rtx && GET_CODE (cond) == GT)
1807 else if (c == const1_rtx && GET_CODE (cond) == LT)
1809 else if (c != CONST0_RTX (GET_MODE (b)))
1812 /* Determine what sort of operation this is. */
1813 switch (GET_CODE (cond))
1832 target = expand_abs_nojump (GET_MODE (if_info->x), b, if_info->x, 1);
1834 /* ??? It's a quandary whether cmove would be better here, especially
1835 for integers. Perhaps combine will clean things up. */
1836 if (target && negate)
1837 target = expand_simple_unop (GET_MODE (target), NEG, target, if_info->x, 0);
1845 if (target != if_info->x)
1846 noce_emit_move_insn (if_info->x, target);
1848 seq = end_ifcvt_sequence (if_info);
1852 emit_insn_before_setloc (seq, if_info->jump, INSN_LOCATOR (if_info->insn_a));
1853 if_info->cond = cond;
1854 if_info->cond_earliest = earliest;
1859 /* Convert "if (m < 0) x = b; else x = 0;" to "x = (m >> C) & b;". */
1862 noce_try_sign_mask (struct noce_if_info *if_info)
1864 rtx cond, t, m, c, seq;
1865 enum machine_mode mode;
1871 cond = if_info->cond;
1872 code = GET_CODE (cond);
1877 if (if_info->a == const0_rtx)
1879 if ((code == LT && c == const0_rtx)
1880 || (code == LE && c == constm1_rtx))
1883 else if (if_info->b == const0_rtx)
1885 if ((code == GE && c == const0_rtx)
1886 || (code == GT && c == constm1_rtx))
1890 if (! t || side_effects_p (t))
1893 /* We currently don't handle different modes. */
1894 mode = GET_MODE (t);
1895 if (GET_MODE (m) != mode)
1898 /* This is only profitable if T is cheap, or T is unconditionally
1899 executed/evaluated in the original insn sequence. The latter
1900 happens if INSN_B was taken from TEST_BB. */
1901 if (rtx_cost (t, SET) >= COSTS_N_INSNS (2)
1902 && (BLOCK_FOR_INSN (if_info->insn_b) != if_info->test_bb
1903 || t != if_info->b))
1907 /* Use emit_store_flag to generate "m < 0 ? -1 : 0" instead of expanding
1908 "(signed) m >> 31" directly. This benefits targets with specialized
1909 insns to obtain the signmask, but still uses ashr_optab otherwise. */
1910 m = emit_store_flag (gen_reg_rtx (mode), LT, m, const0_rtx, mode, 0, -1);
1911 t = m ? expand_binop (mode, and_optab, m, t, NULL_RTX, 0, OPTAB_DIRECT)
1920 noce_emit_move_insn (if_info->x, t);
1922 seq = end_ifcvt_sequence (if_info);
1926 emit_insn_before_setloc (seq, if_info->jump, INSN_LOCATOR (if_info->insn_a));
1931 /* Optimize away "if (x & C) x |= C" and similar bit manipulation
1935 noce_try_bitop (struct noce_if_info *if_info)
1937 rtx cond, x, a, result, seq;
1938 enum machine_mode mode;
1943 cond = if_info->cond;
1944 code = GET_CODE (cond);
1946 /* Check for no else condition. */
1947 if (! rtx_equal_p (x, if_info->b))
1950 /* Check for a suitable condition. */
1951 if (code != NE && code != EQ)
1953 if (XEXP (cond, 1) != const0_rtx)
1955 cond = XEXP (cond, 0);
1957 /* ??? We could also handle AND here. */
1958 if (GET_CODE (cond) == ZERO_EXTRACT)
1960 if (XEXP (cond, 1) != const1_rtx
1961 || GET_CODE (XEXP (cond, 2)) != CONST_INT
1962 || ! rtx_equal_p (x, XEXP (cond, 0)))
1964 bitnum = INTVAL (XEXP (cond, 2));
1965 mode = GET_MODE (x);
1966 if (BITS_BIG_ENDIAN)
1967 bitnum = GET_MODE_BITSIZE (mode) - 1 - bitnum;
1968 if (bitnum < 0 || bitnum >= HOST_BITS_PER_WIDE_INT)
1975 if (GET_CODE (a) == IOR || GET_CODE (a) == XOR)
1977 /* Check for "if (X & C) x = x op C". */
1978 if (! rtx_equal_p (x, XEXP (a, 0))
1979 || GET_CODE (XEXP (a, 1)) != CONST_INT
1980 || (INTVAL (XEXP (a, 1)) & GET_MODE_MASK (mode))
1981 != (unsigned HOST_WIDE_INT) 1 << bitnum)
1984 /* if ((x & C) == 0) x |= C; is transformed to x |= C. */
1985 /* if ((x & C) != 0) x |= C; is transformed to nothing. */
1986 if (GET_CODE (a) == IOR)
1987 result = (code == NE) ? a : NULL_RTX;
1988 else if (code == NE)
1990 /* if ((x & C) == 0) x ^= C; is transformed to x |= C. */
1991 result = gen_int_mode ((HOST_WIDE_INT) 1 << bitnum, mode);
1992 result = simplify_gen_binary (IOR, mode, x, result);
1996 /* if ((x & C) != 0) x ^= C; is transformed to x &= ~C. */
1997 result = gen_int_mode (~((HOST_WIDE_INT) 1 << bitnum), mode);
1998 result = simplify_gen_binary (AND, mode, x, result);
2001 else if (GET_CODE (a) == AND)
2003 /* Check for "if (X & C) x &= ~C". */
2004 if (! rtx_equal_p (x, XEXP (a, 0))
2005 || GET_CODE (XEXP (a, 1)) != CONST_INT
2006 || (INTVAL (XEXP (a, 1)) & GET_MODE_MASK (mode))
2007 != (~((HOST_WIDE_INT) 1 << bitnum) & GET_MODE_MASK (mode)))
2010 /* if ((x & C) == 0) x &= ~C; is transformed to nothing. */
2011 /* if ((x & C) != 0) x &= ~C; is transformed to x &= ~C. */
2012 result = (code == EQ) ? a : NULL_RTX;
2020 noce_emit_move_insn (x, result);
2021 seq = end_ifcvt_sequence (if_info);
2025 emit_insn_before_setloc (seq, if_info->jump,
2026 INSN_LOCATOR (if_info->insn_a));
2032 /* Similar to get_condition, only the resulting condition must be
2033 valid at JUMP, instead of at EARLIEST. */
2036 noce_get_condition (rtx jump, rtx *earliest)
2041 if (! any_condjump_p (jump))
2044 set = pc_set (jump);
2046 /* If this branches to JUMP_LABEL when the condition is false,
2047 reverse the condition. */
2048 reverse = (GET_CODE (XEXP (SET_SRC (set), 2)) == LABEL_REF
2049 && XEXP (XEXP (SET_SRC (set), 2), 0) == JUMP_LABEL (jump));
2051 /* If the condition variable is a register and is MODE_INT, accept it. */
2053 cond = XEXP (SET_SRC (set), 0);
2054 tmp = XEXP (cond, 0);
2055 if (REG_P (tmp) && GET_MODE_CLASS (GET_MODE (tmp)) == MODE_INT)
2060 cond = gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond)),
2061 GET_MODE (cond), tmp, XEXP (cond, 1));
2065 /* Otherwise, fall back on canonicalize_condition to do the dirty
2066 work of manipulating MODE_CC values and COMPARE rtx codes. */
2067 return canonicalize_condition (jump, cond, reverse, earliest,
2068 NULL_RTX, false, true);
2071 /* Initialize for a simple IF-THEN or IF-THEN-ELSE block. We will not
2072 be using conditional execution. Set some fields of IF_INFO based
2073 on CE_INFO: test_bb, cond, jump, cond_earliest. Return TRUE if
2077 noce_init_if_info (struct ce_if_block *ce_info, struct noce_if_info *if_info)
2079 basic_block test_bb = ce_info->test_bb;
2082 /* If test is comprised of && or || elements, don't handle it unless
2083 it is the special case of && elements without an ELSE block. */
2084 if (ce_info->num_multiple_test_blocks)
2086 if (ce_info->else_bb || !ce_info->and_and_p)
2089 ce_info->test_bb = test_bb = ce_info->last_test_bb;
2090 ce_info->num_multiple_test_blocks = 0;
2091 ce_info->num_and_and_blocks = 0;
2092 ce_info->num_or_or_blocks = 0;
2095 /* If this is not a standard conditional jump, we can't parse it. */
2096 jump = BB_END (test_bb);
2097 cond = noce_get_condition (jump, &if_info->cond_earliest);
2101 /* If the conditional jump is more than just a conditional
2102 jump, then we can not do if-conversion on this block. */
2103 if (! onlyjump_p (jump))
2106 /* We must be comparing objects whose modes imply the size. */
2107 if (GET_MODE (XEXP (cond, 0)) == BLKmode)
2110 if_info->test_bb = test_bb;
2111 if_info->cond = cond;
2112 if_info->jump = jump;
2117 /* Return true if OP is ok for if-then-else processing. */
2120 noce_operand_ok (rtx op)
2122 /* We special-case memories, so handle any of them with
2123 no address side effects. */
2125 return ! side_effects_p (XEXP (op, 0));
2127 if (side_effects_p (op))
2130 return ! may_trap_p (op);
2133 /* Return true if a write into MEM may trap or fault. */
2136 noce_mem_write_may_trap_or_fault_p (rtx mem)
2140 if (MEM_READONLY_P (mem))
2143 if (may_trap_or_fault_p (mem))
2146 addr = XEXP (mem, 0);
2148 /* Call target hook to avoid the effects of -fpic etc.... */
2149 addr = targetm.delegitimize_address (addr);
2152 switch (GET_CODE (addr))
2160 addr = XEXP (addr, 0);
2164 addr = XEXP (addr, 1);
2167 if (GET_CODE (XEXP (addr, 1)) == CONST_INT)
2168 addr = XEXP (addr, 0);
2175 if (SYMBOL_REF_DECL (addr)
2176 && decl_readonly_section (SYMBOL_REF_DECL (addr), 0))
2186 /* Given a simple IF-THEN or IF-THEN-ELSE block, attempt to convert it
2187 without using conditional execution. Return TRUE if we were
2188 successful at converting the block. */
2191 noce_process_if_block (struct ce_if_block * ce_info)
2193 basic_block test_bb = ce_info->test_bb; /* test block */
2194 basic_block then_bb = ce_info->then_bb; /* THEN */
2195 basic_block else_bb = ce_info->else_bb; /* ELSE or NULL */
2196 basic_block join_bb;
2197 struct noce_if_info if_info;
2200 rtx orig_x, x, a, b;
2203 /* We're looking for patterns of the form
2205 (1) if (...) x = a; else x = b;
2206 (2) x = b; if (...) x = a;
2207 (3) if (...) x = a; // as if with an initial x = x.
2209 The later patterns require jumps to be more expensive.
2211 ??? For future expansion, look for multiple X in such patterns. */
2213 if (!noce_init_if_info (ce_info, &if_info))
2216 cond = if_info.cond;
2217 jump = if_info.jump;
2219 /* Look for one of the potential sets. */
2220 insn_a = first_active_insn (then_bb);
2222 || insn_a != last_active_insn (then_bb, FALSE)
2223 || (set_a = single_set (insn_a)) == NULL_RTX)
2226 x = SET_DEST (set_a);
2227 a = SET_SRC (set_a);
2229 /* Look for the other potential set. Make sure we've got equivalent
2231 /* ??? This is overconservative. Storing to two different mems is
2232 as easy as conditionally computing the address. Storing to a
2233 single mem merely requires a scratch memory to use as one of the
2234 destination addresses; often the memory immediately below the
2235 stack pointer is available for this. */
2239 insn_b = first_active_insn (else_bb);
2241 || insn_b != last_active_insn (else_bb, FALSE)
2242 || (set_b = single_set (insn_b)) == NULL_RTX
2243 || ! rtx_equal_p (x, SET_DEST (set_b)))
2248 insn_b = prev_nonnote_insn (if_info.cond_earliest);
2249 /* We're going to be moving the evaluation of B down from above
2250 COND_EARLIEST to JUMP. Make sure the relevant data is still
2253 || !NONJUMP_INSN_P (insn_b)
2254 || (set_b = single_set (insn_b)) == NULL_RTX
2255 || ! rtx_equal_p (x, SET_DEST (set_b))
2256 || reg_overlap_mentioned_p (x, SET_SRC (set_b))
2257 || modified_between_p (SET_SRC (set_b),
2258 PREV_INSN (if_info.cond_earliest), jump)
2259 /* Likewise with X. In particular this can happen when
2260 noce_get_condition looks farther back in the instruction
2261 stream than one might expect. */
2262 || reg_overlap_mentioned_p (x, cond)
2263 || reg_overlap_mentioned_p (x, a)
2264 || modified_between_p (x, PREV_INSN (if_info.cond_earliest), jump))
2265 insn_b = set_b = NULL_RTX;
2268 /* If x has side effects then only the if-then-else form is safe to
2269 convert. But even in that case we would need to restore any notes
2270 (such as REG_INC) at then end. That can be tricky if
2271 noce_emit_move_insn expands to more than one insn, so disable the
2272 optimization entirely for now if there are side effects. */
2273 if (side_effects_p (x))
2276 b = (set_b ? SET_SRC (set_b) : x);
2278 /* Only operate on register destinations, and even then avoid extending
2279 the lifetime of hard registers on small register class machines. */
2282 || (SMALL_REGISTER_CLASSES
2283 && REGNO (x) < FIRST_PSEUDO_REGISTER))
2285 if (no_new_pseudos || GET_MODE (x) == BLKmode)
2288 if (GET_MODE (x) == ZERO_EXTRACT
2289 && (GET_CODE (XEXP (x, 1)) != CONST_INT
2290 || GET_CODE (XEXP (x, 2)) != CONST_INT))
2293 x = gen_reg_rtx (GET_MODE (GET_CODE (x) == STRICT_LOW_PART
2294 ? XEXP (x, 0) : x));
2297 /* Don't operate on sources that may trap or are volatile. */
2298 if (! noce_operand_ok (a) || ! noce_operand_ok (b))
2301 /* Set up the info block for our subroutines. */
2302 if_info.insn_a = insn_a;
2303 if_info.insn_b = insn_b;
2308 /* Try optimizations in some approximation of a useful order. */
2309 /* ??? Should first look to see if X is live incoming at all. If it
2310 isn't, we don't need anything but an unconditional set. */
2312 /* Look and see if A and B are really the same. Avoid creating silly
2313 cmove constructs that no one will fix up later. */
2314 if (rtx_equal_p (a, b))
2316 /* If we have an INSN_B, we don't have to create any new rtl. Just
2317 move the instruction that we already have. If we don't have an
2318 INSN_B, that means that A == X, and we've got a noop move. In
2319 that case don't do anything and let the code below delete INSN_A. */
2320 if (insn_b && else_bb)
2324 if (else_bb && insn_b == BB_END (else_bb))
2325 BB_END (else_bb) = PREV_INSN (insn_b);
2326 reorder_insns (insn_b, insn_b, PREV_INSN (jump));
2328 /* If there was a REG_EQUAL note, delete it since it may have been
2329 true due to this insn being after a jump. */
2330 if ((note = find_reg_note (insn_b, REG_EQUAL, NULL_RTX)) != 0)
2331 remove_note (insn_b, note);
2335 /* If we have "x = b; if (...) x = a;", and x has side-effects, then
2336 x must be executed twice. */
2337 else if (insn_b && side_effects_p (orig_x))
2344 /* Disallow the "if (...) x = a;" form (with an implicit "else x = x;")
2345 for optimizations if writing to x may trap or fault, i.e. it's a memory
2346 other than a static var or a stack slot, is misaligned on strict
2347 aligned machines or is read-only.
2348 If x is a read-only memory, then the program is valid only if we
2349 avoid the store into it. If there are stores on both the THEN and
2350 ELSE arms, then we can go ahead with the conversion; either the
2351 program is broken, or the condition is always false such that the
2352 other memory is selected. */
2353 if (!set_b && MEM_P (orig_x) && noce_mem_write_may_trap_or_fault_p (orig_x))
2356 if (noce_try_move (&if_info))
2358 if (noce_try_store_flag (&if_info))
2360 if (noce_try_bitop (&if_info))
2362 if (noce_try_minmax (&if_info))
2364 if (noce_try_abs (&if_info))
2366 if (HAVE_conditional_move
2367 && noce_try_cmove (&if_info))
2369 if (! HAVE_conditional_execution)
2371 if (noce_try_store_flag_constants (&if_info))
2373 if (noce_try_addcc (&if_info))
2375 if (noce_try_store_flag_mask (&if_info))
2377 if (HAVE_conditional_move
2378 && noce_try_cmove_arith (&if_info))
2380 if (noce_try_sign_mask (&if_info))
2388 /* If we used a temporary, fix it up now. */
2394 noce_emit_move_insn (orig_x, x);
2396 set_used_flags (orig_x);
2397 unshare_all_rtl_in_chain (seq);
2400 emit_insn_before_setloc (seq, BB_END (test_bb), INSN_LOCATOR (insn_a));
2403 /* The original THEN and ELSE blocks may now be removed. The test block
2404 must now jump to the join block. If the test block and the join block
2405 can be merged, do so. */
2407 join_bb = single_succ (then_bb);
2410 delete_basic_block (else_bb);
2414 remove_edge (find_edge (test_bb, join_bb));
2416 remove_edge (find_edge (then_bb, join_bb));
2417 redirect_edge_and_branch_force (single_succ_edge (test_bb), join_bb);
2418 delete_basic_block (then_bb);
2421 if (can_merge_blocks_p (test_bb, join_bb))
2423 merge_blocks (test_bb, join_bb);
2427 num_updated_if_blocks++;
2431 /* Check whether a block is suitable for conditional move conversion.
2432 Every insn must be a simple set of a register to a constant or a
2433 register. For each assignment, store the value in the array VALS,
2434 indexed by register number. COND is the condition we will
2438 check_cond_move_block (basic_block bb, rtx *vals, rtx cond)
2442 FOR_BB_INSNS (bb, insn)
2446 if (!INSN_P (insn) || JUMP_P (insn))
2448 set = single_set (insn);
2452 dest = SET_DEST (set);
2453 src = SET_SRC (set);
2455 || (SMALL_REGISTER_CLASSES && HARD_REGISTER_P (dest)))
2458 if (!CONSTANT_P (src) && !register_operand (src, VOIDmode))
2461 if (side_effects_p (src) || side_effects_p (dest))
2464 if (may_trap_p (src) || may_trap_p (dest))
2467 /* Don't try to handle this if the source register was
2468 modified earlier in the block. */
2470 && vals[REGNO (src)] != NULL)
2471 || (GET_CODE (src) == SUBREG && REG_P (SUBREG_REG (src))
2472 && vals[REGNO (SUBREG_REG (src))] != NULL))
2475 /* Don't try to handle this if the destination register was
2476 modified earlier in the block. */
2477 if (vals[REGNO (dest)] != NULL)
2480 /* Don't try to handle this if the condition uses the
2481 destination register. */
2482 if (reg_overlap_mentioned_p (dest, cond))
2485 vals[REGNO (dest)] = src;
2487 /* Don't try to handle this if the source register is modified
2488 later in the block. */
2489 if (!CONSTANT_P (src)
2490 && modified_between_p (src, insn, NEXT_INSN (BB_END (bb))))
2494 /* We can only handle simple jumps at the end of the basic block.
2495 It is almost impossible to update the CFG otherwise. */
2497 if (JUMP_P (insn) && ! onlyjump_p (insn))
2503 /* Given a basic block BB suitable for conditional move conversion,
2504 a condition COND, and arrays THEN_VALS and ELSE_VALS containing the
2505 register values depending on COND, emit the insns in the block as
2506 conditional moves. If ELSE_BLOCK is true, THEN_BB was already
2507 processed. The caller has started a sequence for the conversion.
2508 Return true if successful, false if something goes wrong. */
2511 cond_move_convert_if_block (struct noce_if_info *if_infop,
2512 basic_block bb, rtx cond,
2513 rtx *then_vals, rtx *else_vals,
2517 rtx insn, cond_arg0, cond_arg1;
2519 code = GET_CODE (cond);
2520 cond_arg0 = XEXP (cond, 0);
2521 cond_arg1 = XEXP (cond, 1);
2523 FOR_BB_INSNS (bb, insn)
2525 rtx set, target, dest, t, e;
2528 if (!INSN_P (insn) || JUMP_P (insn))
2530 set = single_set (insn);
2531 gcc_assert (set && REG_P (SET_DEST (set)));
2533 dest = SET_DEST (set);
2534 regno = REGNO (dest);
2536 t = then_vals[regno];
2537 e = else_vals[regno];
2541 /* If this register was set in the then block, we already
2542 handled this case there. */
2555 target = noce_emit_cmove (if_infop, dest, code, cond_arg0, cond_arg1,
2561 noce_emit_move_insn (dest, target);
2567 /* Given a simple IF-THEN or IF-THEN-ELSE block, attempt to convert it
2568 using only conditional moves. Return TRUE if we were successful at
2569 converting the block. */
2572 cond_move_process_if_block (struct ce_if_block *ce_info)
2574 basic_block test_bb = ce_info->test_bb;
2575 basic_block then_bb = ce_info->then_bb;
2576 basic_block else_bb = ce_info->else_bb;
2577 basic_block join_bb;
2578 struct noce_if_info if_info;
2579 rtx jump, cond, seq, loc_insn;
2580 int max_reg, size, c, i;
2584 if (!HAVE_conditional_move || no_new_pseudos)
2587 memset (&if_info, 0, sizeof if_info);
2589 if (!noce_init_if_info (ce_info, &if_info))
2592 cond = if_info.cond;
2593 jump = if_info.jump;
2595 /* Build a mapping for each block to the value used for each
2597 max_reg = max_reg_num ();
2598 size = (max_reg + 1) * sizeof (rtx);
2599 then_vals = (rtx *) alloca (size);
2600 else_vals = (rtx *) alloca (size);
2601 memset (then_vals, 0, size);
2602 memset (else_vals, 0, size);
2604 /* Make sure the blocks are suitable. */
2605 if (!check_cond_move_block (then_bb, then_vals, cond)
2606 || (else_bb && !check_cond_move_block (else_bb, else_vals, cond)))
2609 /* Make sure the blocks can be used together. If the same register
2610 is set in both blocks, and is not set to a constant in both
2611 cases, then both blocks must set it to the same register. We
2612 have already verified that if it is set to a register, that the
2613 source register does not change after the assignment. Also count
2614 the number of registers set in only one of the blocks. */
2616 for (i = 0; i <= max_reg; ++i)
2618 if (!then_vals[i] && !else_vals[i])
2621 if (!then_vals[i] || !else_vals[i])
2625 if (!CONSTANT_P (then_vals[i])
2626 && !CONSTANT_P (else_vals[i])
2627 && !rtx_equal_p (then_vals[i], else_vals[i]))
2632 /* Make sure it is reasonable to convert this block. What matters
2633 is the number of assignments currently made in only one of the
2634 branches, since if we convert we are going to always execute
2636 if (c > MAX_CONDITIONAL_EXECUTE)
2639 /* Try to emit the conditional moves. First do the then block,
2640 then do anything left in the else blocks. */
2642 if (!cond_move_convert_if_block (&if_info, then_bb, cond,
2643 then_vals, else_vals, false)
2645 && !cond_move_convert_if_block (&if_info, else_bb, cond,
2646 then_vals, else_vals, true)))
2651 seq = end_ifcvt_sequence (&if_info);
2655 loc_insn = first_active_insn (then_bb);
2658 loc_insn = first_active_insn (else_bb);
2659 gcc_assert (loc_insn);
2661 emit_insn_before_setloc (seq, jump, INSN_LOCATOR (loc_insn));
2663 join_bb = single_succ (then_bb);
2666 delete_basic_block (else_bb);
2670 remove_edge (find_edge (test_bb, join_bb));
2672 remove_edge (find_edge (then_bb, join_bb));
2673 redirect_edge_and_branch_force (single_succ_edge (test_bb), join_bb);
2674 delete_basic_block (then_bb);
2677 if (can_merge_blocks_p (test_bb, join_bb))
2679 merge_blocks (test_bb, join_bb);
2683 num_updated_if_blocks++;
2688 /* Attempt to convert an IF-THEN or IF-THEN-ELSE block into
2689 straight line code. Return true if successful. */
2692 process_if_block (struct ce_if_block * ce_info)
2694 if (! reload_completed
2695 && noce_process_if_block (ce_info))
2698 if (HAVE_conditional_move
2699 && cond_move_process_if_block (ce_info))
2702 if (HAVE_conditional_execution && reload_completed)
2704 /* If we have && and || tests, try to first handle combining the && and
2705 || tests into the conditional code, and if that fails, go back and
2706 handle it without the && and ||, which at present handles the && case
2707 if there was no ELSE block. */
2708 if (cond_exec_process_if_block (ce_info, TRUE))
2711 if (ce_info->num_multiple_test_blocks)
2715 if (cond_exec_process_if_block (ce_info, FALSE))
2723 /* Merge the blocks and mark for local life update. */
2726 merge_if_block (struct ce_if_block * ce_info)
2728 basic_block test_bb = ce_info->test_bb; /* last test block */
2729 basic_block then_bb = ce_info->then_bb; /* THEN */
2730 basic_block else_bb = ce_info->else_bb; /* ELSE or NULL */
2731 basic_block join_bb = ce_info->join_bb; /* join block */
2732 basic_block combo_bb;
2734 /* All block merging is done into the lower block numbers. */
2738 /* Merge any basic blocks to handle && and || subtests. Each of
2739 the blocks are on the fallthru path from the predecessor block. */
2740 if (ce_info->num_multiple_test_blocks > 0)
2742 basic_block bb = test_bb;
2743 basic_block last_test_bb = ce_info->last_test_bb;
2744 basic_block fallthru = block_fallthru (bb);
2749 fallthru = block_fallthru (bb);
2750 merge_blocks (combo_bb, bb);
2753 while (bb != last_test_bb);
2756 /* Merge TEST block into THEN block. Normally the THEN block won't have a
2757 label, but it might if there were || tests. That label's count should be
2758 zero, and it normally should be removed. */
2762 merge_blocks (combo_bb, then_bb);
2766 /* The ELSE block, if it existed, had a label. That label count
2767 will almost always be zero, but odd things can happen when labels
2768 get their addresses taken. */
2771 merge_blocks (combo_bb, else_bb);
2775 /* If there was no join block reported, that means it was not adjacent
2776 to the others, and so we cannot merge them. */
2780 rtx last = BB_END (combo_bb);
2782 /* The outgoing edge for the current COMBO block should already
2783 be correct. Verify this. */
2784 if (EDGE_COUNT (combo_bb->succs) == 0)
2785 gcc_assert (find_reg_note (last, REG_NORETURN, NULL)
2786 || (NONJUMP_INSN_P (last)
2787 && GET_CODE (PATTERN (last)) == TRAP_IF
2788 && (TRAP_CONDITION (PATTERN (last))
2789 == const_true_rtx)));
2792 /* There should still be something at the end of the THEN or ELSE
2793 blocks taking us to our final destination. */
2794 gcc_assert (JUMP_P (last)
2795 || (EDGE_SUCC (combo_bb, 0)->dest == EXIT_BLOCK_PTR
2797 && SIBLING_CALL_P (last))
2798 || ((EDGE_SUCC (combo_bb, 0)->flags & EDGE_EH)
2799 && can_throw_internal (last)));
2802 /* The JOIN block may have had quite a number of other predecessors too.
2803 Since we've already merged the TEST, THEN and ELSE blocks, we should
2804 have only one remaining edge from our if-then-else diamond. If there
2805 is more than one remaining edge, it must come from elsewhere. There
2806 may be zero incoming edges if the THEN block didn't actually join
2807 back up (as with a call to a non-return function). */
2808 else if (EDGE_COUNT (join_bb->preds) < 2
2809 && join_bb != EXIT_BLOCK_PTR)
2811 /* We can merge the JOIN. */
2812 merge_blocks (combo_bb, join_bb);
2817 /* We cannot merge the JOIN. */
2819 /* The outgoing edge for the current COMBO block should already
2820 be correct. Verify this. */
2821 gcc_assert (single_succ_p (combo_bb)
2822 && single_succ (combo_bb) == join_bb);
2824 /* Remove the jump and cruft from the end of the COMBO block. */
2825 if (join_bb != EXIT_BLOCK_PTR)
2826 tidy_fallthru_edge (single_succ_edge (combo_bb));
2829 num_updated_if_blocks++;
2832 /* Find a block ending in a simple IF condition and try to transform it
2833 in some way. When converting a multi-block condition, put the new code
2834 in the first such block and delete the rest. Return a pointer to this
2835 first block if some transformation was done. Return NULL otherwise. */
2838 find_if_header (basic_block test_bb, int pass)
2840 ce_if_block_t ce_info;
2844 /* The kind of block we're looking for has exactly two successors. */
2845 if (EDGE_COUNT (test_bb->succs) != 2)
2848 then_edge = EDGE_SUCC (test_bb, 0);
2849 else_edge = EDGE_SUCC (test_bb, 1);
2851 /* Neither edge should be abnormal. */
2852 if ((then_edge->flags & EDGE_COMPLEX)
2853 || (else_edge->flags & EDGE_COMPLEX))
2856 /* Nor exit the loop. */
2857 if ((then_edge->flags & EDGE_LOOP_EXIT)
2858 || (else_edge->flags & EDGE_LOOP_EXIT))
2861 /* The THEN edge is canonically the one that falls through. */
2862 if (then_edge->flags & EDGE_FALLTHRU)
2864 else if (else_edge->flags & EDGE_FALLTHRU)
2867 else_edge = then_edge;
2871 /* Otherwise this must be a multiway branch of some sort. */
2874 memset (&ce_info, '\0', sizeof (ce_info));
2875 ce_info.test_bb = test_bb;
2876 ce_info.then_bb = then_edge->dest;
2877 ce_info.else_bb = else_edge->dest;
2878 ce_info.pass = pass;
2880 #ifdef IFCVT_INIT_EXTRA_FIELDS
2881 IFCVT_INIT_EXTRA_FIELDS (&ce_info);
2884 if (find_if_block (&ce_info))
2887 if (HAVE_trap && HAVE_conditional_trap
2888 && find_cond_trap (test_bb, then_edge, else_edge))
2891 if (dom_computed[CDI_POST_DOMINATORS] >= DOM_NO_FAST_QUERY
2892 && (! HAVE_conditional_execution || reload_completed))
2894 if (find_if_case_1 (test_bb, then_edge, else_edge))
2896 if (find_if_case_2 (test_bb, then_edge, else_edge))
2904 fprintf (dump_file, "Conversion succeeded on pass %d.\n", pass);
2905 return ce_info.test_bb;
2908 /* Return true if a block has two edges, one of which falls through to the next
2909 block, and the other jumps to a specific block, so that we can tell if the
2910 block is part of an && test or an || test. Returns either -1 or the number
2911 of non-note, non-jump, non-USE/CLOBBER insns in the block. */
2914 block_jumps_and_fallthru_p (basic_block cur_bb, basic_block target_bb)
2917 int fallthru_p = FALSE;
2924 if (!cur_bb || !target_bb)
2927 /* If no edges, obviously it doesn't jump or fallthru. */
2928 if (EDGE_COUNT (cur_bb->succs) == 0)
2931 FOR_EACH_EDGE (cur_edge, ei, cur_bb->succs)
2933 if (cur_edge->flags & EDGE_COMPLEX)
2934 /* Anything complex isn't what we want. */
2937 else if (cur_edge->flags & EDGE_FALLTHRU)
2940 else if (cur_edge->dest == target_bb)
2947 if ((jump_p & fallthru_p) == 0)
2950 /* Don't allow calls in the block, since this is used to group && and ||
2951 together for conditional execution support. ??? we should support
2952 conditional execution support across calls for IA-64 some day, but
2953 for now it makes the code simpler. */
2954 end = BB_END (cur_bb);
2955 insn = BB_HEAD (cur_bb);
2957 while (insn != NULL_RTX)
2964 && GET_CODE (PATTERN (insn)) != USE
2965 && GET_CODE (PATTERN (insn)) != CLOBBER)
2971 insn = NEXT_INSN (insn);
2977 /* Determine if a given basic block heads a simple IF-THEN or IF-THEN-ELSE
2978 block. If so, we'll try to convert the insns to not require the branch.
2979 Return TRUE if we were successful at converting the block. */
2982 find_if_block (struct ce_if_block * ce_info)
2984 basic_block test_bb = ce_info->test_bb;
2985 basic_block then_bb = ce_info->then_bb;
2986 basic_block else_bb = ce_info->else_bb;
2987 basic_block join_bb = NULL_BLOCK;
2992 ce_info->last_test_bb = test_bb;
2994 /* Discover if any fall through predecessors of the current test basic block
2995 were && tests (which jump to the else block) or || tests (which jump to
2997 if (HAVE_conditional_execution && reload_completed
2998 && single_pred_p (test_bb)
2999 && single_pred_edge (test_bb)->flags == EDGE_FALLTHRU)
3001 basic_block bb = single_pred (test_bb);
3002 basic_block target_bb;
3003 int max_insns = MAX_CONDITIONAL_EXECUTE;
3006 /* Determine if the preceding block is an && or || block. */
3007 if ((n_insns = block_jumps_and_fallthru_p (bb, else_bb)) >= 0)
3009 ce_info->and_and_p = TRUE;
3010 target_bb = else_bb;
3012 else if ((n_insns = block_jumps_and_fallthru_p (bb, then_bb)) >= 0)
3014 ce_info->and_and_p = FALSE;
3015 target_bb = then_bb;
3018 target_bb = NULL_BLOCK;
3020 if (target_bb && n_insns <= max_insns)
3022 int total_insns = 0;
3025 ce_info->last_test_bb = test_bb;
3027 /* Found at least one && or || block, look for more. */
3030 ce_info->test_bb = test_bb = bb;
3031 total_insns += n_insns;
3034 if (!single_pred_p (bb))
3037 bb = single_pred (bb);
3038 n_insns = block_jumps_and_fallthru_p (bb, target_bb);
3040 while (n_insns >= 0 && (total_insns + n_insns) <= max_insns);
3042 ce_info->num_multiple_test_blocks = blocks;
3043 ce_info->num_multiple_test_insns = total_insns;
3045 if (ce_info->and_and_p)
3046 ce_info->num_and_and_blocks = blocks;
3048 ce_info->num_or_or_blocks = blocks;
3052 /* The THEN block of an IF-THEN combo must have exactly one predecessor,
3053 other than any || blocks which jump to the THEN block. */
3054 if ((EDGE_COUNT (then_bb->preds) - ce_info->num_or_or_blocks) != 1)
3057 /* The edges of the THEN and ELSE blocks cannot have complex edges. */
3058 FOR_EACH_EDGE (cur_edge, ei, then_bb->preds)
3060 if (cur_edge->flags & EDGE_COMPLEX)
3064 FOR_EACH_EDGE (cur_edge, ei, else_bb->preds)
3066 if (cur_edge->flags & EDGE_COMPLEX)
3070 /* The THEN block of an IF-THEN combo must have zero or one successors. */
3071 if (EDGE_COUNT (then_bb->succs) > 0
3072 && (!single_succ_p (then_bb)
3073 || (single_succ_edge (then_bb)->flags & EDGE_COMPLEX)
3074 || (flow2_completed && tablejump_p (BB_END (then_bb), NULL, NULL))))
3077 /* If the THEN block has no successors, conditional execution can still
3078 make a conditional call. Don't do this unless the ELSE block has
3079 only one incoming edge -- the CFG manipulation is too ugly otherwise.
3080 Check for the last insn of the THEN block being an indirect jump, which
3081 is listed as not having any successors, but confuses the rest of the CE
3082 code processing. ??? we should fix this in the future. */
3083 if (EDGE_COUNT (then_bb->succs) == 0)
3085 if (single_pred_p (else_bb))
3087 rtx last_insn = BB_END (then_bb);
3090 && NOTE_P (last_insn)
3091 && last_insn != BB_HEAD (then_bb))
3092 last_insn = PREV_INSN (last_insn);
3095 && JUMP_P (last_insn)
3096 && ! simplejump_p (last_insn))
3100 else_bb = NULL_BLOCK;
3106 /* If the THEN block's successor is the other edge out of the TEST block,
3107 then we have an IF-THEN combo without an ELSE. */
3108 else if (single_succ (then_bb) == else_bb)
3111 else_bb = NULL_BLOCK;
3114 /* If the THEN and ELSE block meet in a subsequent block, and the ELSE
3115 has exactly one predecessor and one successor, and the outgoing edge
3116 is not complex, then we have an IF-THEN-ELSE combo. */
3117 else if (single_succ_p (else_bb)
3118 && single_succ (then_bb) == single_succ (else_bb)
3119 && single_pred_p (else_bb)
3120 && ! (single_succ_edge (else_bb)->flags & EDGE_COMPLEX)
3121 && ! (flow2_completed && tablejump_p (BB_END (else_bb), NULL, NULL)))
3122 join_bb = single_succ (else_bb);
3124 /* Otherwise it is not an IF-THEN or IF-THEN-ELSE combination. */
3128 num_possible_if_blocks++;
3133 "\nIF-THEN%s block found, pass %d, start block %d "
3134 "[insn %d], then %d [%d]",
3135 (else_bb) ? "-ELSE" : "",
3138 BB_HEAD (test_bb) ? (int)INSN_UID (BB_HEAD (test_bb)) : -1,
3140 BB_HEAD (then_bb) ? (int)INSN_UID (BB_HEAD (then_bb)) : -1);
3143 fprintf (dump_file, ", else %d [%d]",
3145 BB_HEAD (else_bb) ? (int)INSN_UID (BB_HEAD (else_bb)) : -1);
3147 fprintf (dump_file, ", join %d [%d]",
3149 BB_HEAD (join_bb) ? (int)INSN_UID (BB_HEAD (join_bb)) : -1);
3151 if (ce_info->num_multiple_test_blocks > 0)
3152 fprintf (dump_file, ", %d %s block%s last test %d [%d]",
3153 ce_info->num_multiple_test_blocks,
3154 (ce_info->and_and_p) ? "&&" : "||",
3155 (ce_info->num_multiple_test_blocks == 1) ? "" : "s",
3156 ce_info->last_test_bb->index,
3157 ((BB_HEAD (ce_info->last_test_bb))
3158 ? (int)INSN_UID (BB_HEAD (ce_info->last_test_bb))
3161 fputc ('\n', dump_file);
3164 /* Make sure IF, THEN, and ELSE, blocks are adjacent. Actually, we get the
3165 first condition for free, since we've already asserted that there's a
3166 fallthru edge from IF to THEN. Likewise for the && and || blocks, since
3167 we checked the FALLTHRU flag, those are already adjacent to the last IF
3169 /* ??? As an enhancement, move the ELSE block. Have to deal with
3170 BLOCK notes, if by no other means than backing out the merge if they
3171 exist. Sticky enough I don't want to think about it now. */
3173 if (else_bb && (next = next->next_bb) != else_bb)
3175 if ((next = next->next_bb) != join_bb && join_bb != EXIT_BLOCK_PTR)
3183 /* Do the real work. */
3184 ce_info->else_bb = else_bb;
3185 ce_info->join_bb = join_bb;
3187 return process_if_block (ce_info);
3190 /* Convert a branch over a trap, or a branch
3191 to a trap, into a conditional trap. */
3194 find_cond_trap (basic_block test_bb, edge then_edge, edge else_edge)
3196 basic_block then_bb = then_edge->dest;
3197 basic_block else_bb = else_edge->dest;
3198 basic_block other_bb, trap_bb;
3199 rtx trap, jump, cond, cond_earliest, seq;
3202 /* Locate the block with the trap instruction. */
3203 /* ??? While we look for no successors, we really ought to allow
3204 EH successors. Need to fix merge_if_block for that to work. */
3205 if ((trap = block_has_only_trap (then_bb)) != NULL)
3206 trap_bb = then_bb, other_bb = else_bb;
3207 else if ((trap = block_has_only_trap (else_bb)) != NULL)
3208 trap_bb = else_bb, other_bb = then_bb;
3214 fprintf (dump_file, "\nTRAP-IF block found, start %d, trap %d\n",
3215 test_bb->index, trap_bb->index);
3218 /* If this is not a standard conditional jump, we can't parse it. */
3219 jump = BB_END (test_bb);
3220 cond = noce_get_condition (jump, &cond_earliest);
3224 /* If the conditional jump is more than just a conditional jump, then
3225 we can not do if-conversion on this block. */
3226 if (! onlyjump_p (jump))
3229 /* We must be comparing objects whose modes imply the size. */
3230 if (GET_MODE (XEXP (cond, 0)) == BLKmode)
3233 /* Reverse the comparison code, if necessary. */
3234 code = GET_CODE (cond);
3235 if (then_bb == trap_bb)
3237 code = reversed_comparison_code (cond, jump);
3238 if (code == UNKNOWN)
3242 /* Attempt to generate the conditional trap. */
3243 seq = gen_cond_trap (code, XEXP (cond, 0),
3245 TRAP_CODE (PATTERN (trap)));
3249 /* Emit the new insns before cond_earliest. */
3250 emit_insn_before_setloc (seq, cond_earliest, INSN_LOCATOR (trap));
3252 /* Delete the trap block if possible. */
3253 remove_edge (trap_bb == then_bb ? then_edge : else_edge);
3254 if (EDGE_COUNT (trap_bb->preds) == 0)
3256 delete_basic_block (trap_bb);
3260 /* Wire together the blocks again. */
3261 if (current_ir_type () == IR_RTL_CFGLAYOUT)
3262 single_succ_edge (test_bb)->flags |= EDGE_FALLTHRU;
3267 lab = JUMP_LABEL (jump);
3268 newjump = emit_jump_insn_after (gen_jump (lab), jump);
3269 LABEL_NUSES (lab) += 1;
3270 JUMP_LABEL (newjump) = lab;
3271 emit_barrier_after (newjump);
3275 if (can_merge_blocks_p (test_bb, other_bb))
3277 merge_blocks (test_bb, other_bb);
3281 num_updated_if_blocks++;
3285 /* Subroutine of find_cond_trap: if BB contains only a trap insn,
3289 block_has_only_trap (basic_block bb)
3293 /* We're not the exit block. */
3294 if (bb == EXIT_BLOCK_PTR)
3297 /* The block must have no successors. */
3298 if (EDGE_COUNT (bb->succs) > 0)
3301 /* The only instruction in the THEN block must be the trap. */
3302 trap = first_active_insn (bb);
3303 if (! (trap == BB_END (bb)
3304 && GET_CODE (PATTERN (trap)) == TRAP_IF
3305 && TRAP_CONDITION (PATTERN (trap)) == const_true_rtx))
3311 /* Look for IF-THEN-ELSE cases in which one of THEN or ELSE is
3312 transformable, but not necessarily the other. There need be no
3315 Return TRUE if we were successful at converting the block.
3317 Cases we'd like to look at:
3320 if (test) goto over; // x not live
3328 if (! test) goto label;
3331 if (test) goto E; // x not live
3345 (3) // This one's really only interesting for targets that can do
3346 // multiway branching, e.g. IA-64 BBB bundles. For other targets
3347 // it results in multiple branches on a cache line, which often
3348 // does not sit well with predictors.
3350 if (test1) goto E; // predicted not taken
3366 (A) Don't do (2) if the branch is predicted against the block we're
3367 eliminating. Do it anyway if we can eliminate a branch; this requires
3368 that the sole successor of the eliminated block postdominate the other
3371 (B) With CE, on (3) we can steal from both sides of the if, creating
3380 Again, this is most useful if J postdominates.
3382 (C) CE substitutes for helpful life information.
3384 (D) These heuristics need a lot of work. */
3386 /* Tests for case 1 above. */
3389 find_if_case_1 (basic_block test_bb, edge then_edge, edge else_edge)
3391 basic_block then_bb = then_edge->dest;
3392 basic_block else_bb = else_edge->dest, new_bb;
3395 /* If we are partitioning hot/cold basic blocks, we don't want to
3396 mess up unconditional or indirect jumps that cross between hot
3399 Basic block partitioning may result in some jumps that appear to
3400 be optimizable (or blocks that appear to be mergeable), but which really
3401 must be left untouched (they are required to make it safely across
3402 partition boundaries). See the comments at the top of
3403 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
3405 if ((BB_END (then_bb)
3406 && find_reg_note (BB_END (then_bb), REG_CROSSING_JUMP, NULL_RTX))
3407 || (BB_END (test_bb)
3408 && find_reg_note (BB_END (test_bb), REG_CROSSING_JUMP, NULL_RTX))
3409 || (BB_END (else_bb)
3410 && find_reg_note (BB_END (else_bb), REG_CROSSING_JUMP,
3414 /* THEN has one successor. */
3415 if (!single_succ_p (then_bb))
3418 /* THEN does not fall through, but is not strange either. */
3419 if (single_succ_edge (then_bb)->flags & (EDGE_COMPLEX | EDGE_FALLTHRU))
3422 /* THEN has one predecessor. */
3423 if (!single_pred_p (then_bb))
3426 /* THEN must do something. */
3427 if (forwarder_block_p (then_bb))
3430 num_possible_if_blocks++;
3433 "\nIF-CASE-1 found, start %d, then %d\n",
3434 test_bb->index, then_bb->index);
3436 /* THEN is small. */
3437 if (! cheap_bb_rtx_cost_p (then_bb, COSTS_N_INSNS (BRANCH_COST)))
3440 /* Registers set are dead, or are predicable. */
3441 if (! dead_or_predicable (test_bb, then_bb, else_bb,
3442 single_succ (then_bb), 1))
3445 /* Conversion went ok, including moving the insns and fixing up the
3446 jump. Adjust the CFG to match. */
3448 bitmap_ior (test_bb->il.rtl->global_live_at_end,
3449 else_bb->il.rtl->global_live_at_start,
3450 then_bb->il.rtl->global_live_at_end);
3453 /* We can avoid creating a new basic block if then_bb is immediately
3454 followed by else_bb, i.e. deleting then_bb allows test_bb to fall
3457 if (then_bb->next_bb == else_bb
3458 && then_bb->prev_bb == test_bb
3459 && else_bb != EXIT_BLOCK_PTR)
3461 redirect_edge_succ (FALLTHRU_EDGE (test_bb), else_bb);
3465 new_bb = redirect_edge_and_branch_force (FALLTHRU_EDGE (test_bb),
3468 then_bb_index = then_bb->index;
3469 delete_basic_block (then_bb);
3471 /* Make rest of code believe that the newly created block is the THEN_BB
3472 block we removed. */
3475 new_bb->index = then_bb_index;
3476 SET_BASIC_BLOCK (then_bb_index, new_bb);
3477 /* Since the fallthru edge was redirected from test_bb to new_bb,
3478 we need to ensure that new_bb is in the same partition as
3479 test bb (you can not fall through across section boundaries). */
3480 BB_COPY_PARTITION (new_bb, test_bb);
3482 /* We've possibly created jump to next insn, cleanup_cfg will solve that
3486 num_updated_if_blocks++;
3491 /* Test for case 2 above. */
3494 find_if_case_2 (basic_block test_bb, edge then_edge, edge else_edge)
3496 basic_block then_bb = then_edge->dest;
3497 basic_block else_bb = else_edge->dest;
3501 /* If we are partitioning hot/cold basic blocks, we don't want to
3502 mess up unconditional or indirect jumps that cross between hot
3505 Basic block partitioning may result in some jumps that appear to
3506 be optimizable (or blocks that appear to be mergeable), but which really
3507 must be left untouched (they are required to make it safely across
3508 partition boundaries). See the comments at the top of
3509 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
3511 if ((BB_END (then_bb)
3512 && find_reg_note (BB_END (then_bb), REG_CROSSING_JUMP, NULL_RTX))
3513 || (BB_END (test_bb)
3514 && find_reg_note (BB_END (test_bb), REG_CROSSING_JUMP, NULL_RTX))
3515 || (BB_END (else_bb)
3516 && find_reg_note (BB_END (else_bb), REG_CROSSING_JUMP,
3520 /* ELSE has one successor. */
3521 if (!single_succ_p (else_bb))
3524 else_succ = single_succ_edge (else_bb);
3526 /* ELSE outgoing edge is not complex. */
3527 if (else_succ->flags & EDGE_COMPLEX)
3530 /* ELSE has one predecessor. */
3531 if (!single_pred_p (else_bb))
3534 /* THEN is not EXIT. */
3535 if (then_bb->index < NUM_FIXED_BLOCKS)
3538 /* ELSE is predicted or SUCC(ELSE) postdominates THEN. */
3539 note = find_reg_note (BB_END (test_bb), REG_BR_PROB, NULL_RTX);
3540 if (note && INTVAL (XEXP (note, 0)) >= REG_BR_PROB_BASE / 2)
3542 else if (else_succ->dest->index < NUM_FIXED_BLOCKS
3543 || dominated_by_p (CDI_POST_DOMINATORS, then_bb,
3549 num_possible_if_blocks++;
3552 "\nIF-CASE-2 found, start %d, else %d\n",
3553 test_bb->index, else_bb->index);
3555 /* ELSE is small. */
3556 if (! cheap_bb_rtx_cost_p (else_bb, COSTS_N_INSNS (BRANCH_COST)))
3559 /* Registers set are dead, or are predicable. */
3560 if (! dead_or_predicable (test_bb, else_bb, then_bb, else_succ->dest, 0))
3563 /* Conversion went ok, including moving the insns and fixing up the
3564 jump. Adjust the CFG to match. */
3566 bitmap_ior (test_bb->il.rtl->global_live_at_end,
3567 then_bb->il.rtl->global_live_at_start,
3568 else_bb->il.rtl->global_live_at_end);
3570 delete_basic_block (else_bb);
3573 num_updated_if_blocks++;
3575 /* ??? We may now fallthru from one of THEN's successors into a join
3576 block. Rerun cleanup_cfg? Examine things manually? Wait? */
3581 /* A subroutine of dead_or_predicable called through for_each_rtx.
3582 Return 1 if a memory is found. */
3585 find_memory (rtx *px, void *data ATTRIBUTE_UNUSED)
3590 /* Used by the code above to perform the actual rtl transformations.
3591 Return TRUE if successful.
3593 TEST_BB is the block containing the conditional branch. MERGE_BB
3594 is the block containing the code to manipulate. NEW_DEST is the
3595 label TEST_BB should be branching to after the conversion.
3596 REVERSEP is true if the sense of the branch should be reversed. */
3599 dead_or_predicable (basic_block test_bb, basic_block merge_bb,
3600 basic_block other_bb, basic_block new_dest, int reversep)
3602 rtx head, end, jump, earliest = NULL_RTX, old_dest, new_label = NULL_RTX;
3604 jump = BB_END (test_bb);
3606 /* Find the extent of the real code in the merge block. */
3607 head = BB_HEAD (merge_bb);
3608 end = BB_END (merge_bb);
3610 /* If merge_bb ends with a tablejump, predicating/moving insn's
3611 into test_bb and then deleting merge_bb will result in the jumptable
3612 that follows merge_bb being removed along with merge_bb and then we
3613 get an unresolved reference to the jumptable. */
3614 if (tablejump_p (end, NULL, NULL))
3618 head = NEXT_INSN (head);
3623 head = end = NULL_RTX;
3626 head = NEXT_INSN (head);
3633 head = end = NULL_RTX;
3636 end = PREV_INSN (end);
3639 /* Disable handling dead code by conditional execution if the machine needs
3640 to do anything funny with the tests, etc. */
3641 #ifndef IFCVT_MODIFY_TESTS
3642 if (HAVE_conditional_execution)
3644 /* In the conditional execution case, we have things easy. We know
3645 the condition is reversible. We don't have to check life info
3646 because we're going to conditionally execute the code anyway.
3647 All that's left is making sure the insns involved can actually
3652 cond = cond_exec_get_condition (jump);
3656 prob_val = find_reg_note (jump, REG_BR_PROB, NULL_RTX);
3658 prob_val = XEXP (prob_val, 0);
3662 enum rtx_code rev = reversed_comparison_code (cond, jump);
3665 cond = gen_rtx_fmt_ee (rev, GET_MODE (cond), XEXP (cond, 0),
3668 prob_val = GEN_INT (REG_BR_PROB_BASE - INTVAL (prob_val));
3671 if (! cond_exec_process_insns ((ce_if_block_t *)0, head, end, cond,
3680 /* In the non-conditional execution case, we have to verify that there
3681 are no trapping operations, no calls, no references to memory, and
3682 that any registers modified are dead at the branch site. */
3684 rtx insn, cond, prev;
3685 regset merge_set, tmp, test_live, test_set;
3686 struct propagate_block_info *pbi;
3687 unsigned i, fail = 0;
3690 /* Check for no calls or trapping operations. */
3691 for (insn = head; ; insn = NEXT_INSN (insn))
3697 if (may_trap_p (PATTERN (insn)))
3700 /* ??? Even non-trapping memories such as stack frame
3701 references must be avoided. For stores, we collect
3702 no lifetime info; for reads, we'd have to assert
3703 true_dependence false against every store in the
3705 if (for_each_rtx (&PATTERN (insn), find_memory, NULL))
3712 if (! any_condjump_p (jump))
3715 /* Find the extent of the conditional. */
3716 cond = noce_get_condition (jump, &earliest);
3721 MERGE_SET = set of registers set in MERGE_BB
3722 TEST_LIVE = set of registers live at EARLIEST
3723 TEST_SET = set of registers set between EARLIEST and the
3724 end of the block. */
3726 tmp = ALLOC_REG_SET (®_obstack);
3727 merge_set = ALLOC_REG_SET (®_obstack);
3728 test_live = ALLOC_REG_SET (®_obstack);
3729 test_set = ALLOC_REG_SET (®_obstack);
3731 /* ??? bb->local_set is only valid during calculate_global_regs_live,
3732 so we must recompute usage for MERGE_BB. Not so bad, I suppose,
3733 since we've already asserted that MERGE_BB is small. */
3734 /* If we allocated new pseudos (e.g. in the conditional move
3735 expander called from noce_emit_cmove), we must resize the
3737 if (max_regno < max_reg_num ())
3739 max_regno = max_reg_num ();
3740 allocate_reg_info (max_regno, FALSE, FALSE);
3742 propagate_block (merge_bb, tmp, merge_set, merge_set, 0);
3744 /* For small register class machines, don't lengthen lifetimes of
3745 hard registers before reload. */
3746 if (SMALL_REGISTER_CLASSES && ! reload_completed)
3748 EXECUTE_IF_SET_IN_BITMAP (merge_set, 0, i, bi)
3750 if (i < FIRST_PSEUDO_REGISTER
3752 && ! global_regs[i])
3757 /* For TEST, we're interested in a range of insns, not a whole block.
3758 Moreover, we're interested in the insns live from OTHER_BB. */
3760 COPY_REG_SET (test_live, other_bb->il.rtl->global_live_at_start);
3761 pbi = init_propagate_block_info (test_bb, test_live, test_set, test_set,
3764 for (insn = jump; ; insn = prev)
3766 prev = propagate_one_insn (pbi, insn);
3767 if (insn == earliest)
3771 free_propagate_block_info (pbi);
3773 /* We can perform the transformation if
3774 MERGE_SET & (TEST_SET | TEST_LIVE)
3776 TEST_SET & merge_bb->il.rtl->global_live_at_start
3779 if (bitmap_intersect_p (test_set, merge_set)
3780 || bitmap_intersect_p (test_live, merge_set)
3781 || bitmap_intersect_p (test_set,
3782 merge_bb->il.rtl->global_live_at_start))
3786 FREE_REG_SET (merge_set);
3787 FREE_REG_SET (test_live);
3788 FREE_REG_SET (test_set);
3795 /* We don't want to use normal invert_jump or redirect_jump because
3796 we don't want to delete_insn called. Also, we want to do our own
3797 change group management. */
3799 old_dest = JUMP_LABEL (jump);
3800 if (other_bb != new_dest)
3802 new_label = block_label (new_dest);
3804 ? ! invert_jump_1 (jump, new_label)
3805 : ! redirect_jump_1 (jump, new_label))
3809 if (! apply_change_group ())
3812 if (other_bb != new_dest)
3814 redirect_jump_2 (jump, old_dest, new_label, 0, reversep);
3816 redirect_edge_succ (BRANCH_EDGE (test_bb), new_dest);
3819 gcov_type count, probability;
3820 count = BRANCH_EDGE (test_bb)->count;
3821 BRANCH_EDGE (test_bb)->count = FALLTHRU_EDGE (test_bb)->count;
3822 FALLTHRU_EDGE (test_bb)->count = count;
3823 probability = BRANCH_EDGE (test_bb)->probability;
3824 BRANCH_EDGE (test_bb)->probability
3825 = FALLTHRU_EDGE (test_bb)->probability;
3826 FALLTHRU_EDGE (test_bb)->probability = probability;
3827 update_br_prob_note (test_bb);
3831 /* Move the insns out of MERGE_BB to before the branch. */
3836 if (end == BB_END (merge_bb))
3837 BB_END (merge_bb) = PREV_INSN (head);
3839 if (squeeze_notes (&head, &end))
3842 /* PR 21767: When moving insns above a conditional branch, REG_EQUAL
3843 notes might become invalid. */
3849 if (! INSN_P (insn))
3851 note = find_reg_note (insn, REG_EQUAL, NULL_RTX);
3854 set = single_set (insn);
3855 if (!set || !function_invariant_p (SET_SRC (set)))
3856 remove_note (insn, note);
3857 } while (insn != end && (insn = NEXT_INSN (insn)));
3859 reorder_insns (head, end, PREV_INSN (earliest));
3862 /* Remove the jump and edge if we can. */
3863 if (other_bb == new_dest)
3866 remove_edge (BRANCH_EDGE (test_bb));
3867 /* ??? Can't merge blocks here, as then_bb is still in use.
3868 At minimum, the merge will get done just before bb-reorder. */
3878 /* Main entry point for all if-conversion. */
3881 if_convert (int x_life_data_ok)
3886 num_possible_if_blocks = 0;
3887 num_updated_if_blocks = 0;
3888 num_true_changes = 0;
3889 life_data_ok = (x_life_data_ok != 0);
3891 if ((! targetm.cannot_modify_jumps_p ())
3892 && (!flag_reorder_blocks_and_partition || !no_new_pseudos
3893 || !targetm.have_named_sections))
3895 loop_optimizer_init (0);
3898 mark_loop_exit_edges ();
3899 loop_optimizer_finalize ();
3901 free_dominance_info (CDI_DOMINATORS);
3904 /* Compute postdominators if we think we'll use them. */
3905 if (HAVE_conditional_execution || life_data_ok)
3906 calculate_dominance_info (CDI_POST_DOMINATORS);
3911 /* Go through each of the basic blocks looking for things to convert. If we
3912 have conditional execution, we make multiple passes to allow us to handle
3913 IF-THEN{-ELSE} blocks within other IF-THEN{-ELSE} blocks. */
3917 cond_exec_changed_p = FALSE;
3920 #ifdef IFCVT_MULTIPLE_DUMPS
3921 if (dump_file && pass > 1)
3922 fprintf (dump_file, "\n\n========== Pass %d ==========\n", pass);
3928 while ((new_bb = find_if_header (bb, pass)))
3932 #ifdef IFCVT_MULTIPLE_DUMPS
3933 if (dump_file && cond_exec_changed_p)
3934 print_rtl_with_bb (dump_file, get_insns ());
3937 while (cond_exec_changed_p);
3939 #ifdef IFCVT_MULTIPLE_DUMPS
3941 fprintf (dump_file, "\n\n========== no more changes\n");
3944 free_dominance_info (CDI_POST_DOMINATORS);
3949 clear_aux_for_blocks ();
3951 /* Rebuild life info for basic blocks that require it. */
3952 if (num_true_changes && life_data_ok)
3954 /* If we allocated new pseudos, we must resize the array for sched1. */
3955 if (max_regno < max_reg_num ())
3957 max_regno = max_reg_num ();
3958 allocate_reg_info (max_regno, FALSE, FALSE);
3960 update_life_info_in_dirty_blocks (UPDATE_LIFE_GLOBAL_RM_NOTES,
3961 PROP_DEATH_NOTES | PROP_SCAN_DEAD_CODE
3962 | PROP_KILL_DEAD_CODE);
3965 /* Write the final stats. */
3966 if (dump_file && num_possible_if_blocks > 0)
3969 "\n%d possible IF blocks searched.\n",
3970 num_possible_if_blocks);
3972 "%d IF blocks converted.\n",
3973 num_updated_if_blocks);
3975 "%d true changes made.\n\n\n",
3979 #ifdef ENABLE_CHECKING
3980 verify_flow_info ();
3985 gate_handle_if_conversion (void)
3987 return (optimize > 0);
3990 /* If-conversion and CFG cleanup. */
3992 rest_of_handle_if_conversion (void)
3994 if (flag_if_conversion)
3997 dump_flow_info (dump_file, dump_flags);
3998 cleanup_cfg (CLEANUP_EXPENSIVE);
3999 reg_scan (get_insns (), max_reg_num ());
4003 timevar_push (TV_JUMP);
4004 cleanup_cfg (CLEANUP_EXPENSIVE);
4005 reg_scan (get_insns (), max_reg_num ());
4006 timevar_pop (TV_JUMP);
4010 struct tree_opt_pass pass_rtl_ifcvt =
4013 gate_handle_if_conversion, /* gate */
4014 rest_of_handle_if_conversion, /* execute */
4017 0, /* static_pass_number */
4018 TV_IFCVT, /* tv_id */
4019 0, /* properties_required */
4020 0, /* properties_provided */
4021 0, /* properties_destroyed */
4022 0, /* todo_flags_start */
4023 TODO_dump_func, /* todo_flags_finish */
4028 gate_handle_if_after_combine (void)
4030 return (optimize > 0 && flag_if_conversion);
4034 /* Rerun if-conversion, as combine may have simplified things enough
4035 to now meet sequence length restrictions. */
4037 rest_of_handle_if_after_combine (void)
4045 struct tree_opt_pass pass_if_after_combine =
4048 gate_handle_if_after_combine, /* gate */
4049 rest_of_handle_if_after_combine, /* execute */
4052 0, /* static_pass_number */
4053 TV_IFCVT, /* tv_id */
4054 0, /* properties_required */
4055 0, /* properties_provided */
4056 0, /* properties_destroyed */
4057 0, /* todo_flags_start */
4059 TODO_ggc_collect, /* todo_flags_finish */
4065 gate_handle_if_after_reload (void)
4067 return (optimize > 0);
4071 rest_of_handle_if_after_reload (void)
4073 /* Last attempt to optimize CFG, as scheduling, peepholing and insn
4074 splitting possibly introduced more crossjumping opportunities. */
4075 cleanup_cfg (CLEANUP_EXPENSIVE
4076 | CLEANUP_UPDATE_LIFE
4077 | (flag_crossjumping ? CLEANUP_CROSSJUMP : 0));
4078 if (flag_if_conversion2)
4084 struct tree_opt_pass pass_if_after_reload =
4087 gate_handle_if_after_reload, /* gate */
4088 rest_of_handle_if_after_reload, /* execute */
4091 0, /* static_pass_number */
4092 TV_IFCVT2, /* tv_id */
4093 0, /* properties_required */
4094 0, /* properties_provided */
4095 0, /* properties_destroyed */
4096 0, /* todo_flags_start */
4098 TODO_ggc_collect, /* todo_flags_finish */