1 /* If-conversion support.
2 Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007
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"
50 #ifndef HAVE_conditional_execution
51 #define HAVE_conditional_execution 0
53 #ifndef HAVE_conditional_move
54 #define HAVE_conditional_move 0
65 #ifndef HAVE_conditional_trap
66 #define HAVE_conditional_trap 0
69 #ifndef MAX_CONDITIONAL_EXECUTE
70 #define MAX_CONDITIONAL_EXECUTE (BRANCH_COST + 1)
73 #define NULL_BLOCK ((basic_block) NULL)
75 /* # of IF-THEN or IF-THEN-ELSE blocks we looked at */
76 static int num_possible_if_blocks;
78 /* # of IF-THEN or IF-THEN-ELSE blocks were converted to conditional
80 static int num_updated_if_blocks;
82 /* # of changes made which require life information to be updated. */
83 static int num_true_changes;
85 /* Whether conditional execution changes were made. */
86 static int cond_exec_changed_p;
88 /* True if life data ok at present. */
89 static bool life_data_ok;
91 /* Forward references. */
92 static int count_bb_insns (basic_block);
93 static bool cheap_bb_rtx_cost_p (basic_block, int);
94 static rtx first_active_insn (basic_block);
95 static rtx last_active_insn (basic_block, int);
96 static basic_block block_fallthru (basic_block);
97 static int cond_exec_process_insns (ce_if_block_t *, rtx, rtx, rtx, rtx, int);
98 static rtx cond_exec_get_condition (rtx);
99 static int cond_exec_process_if_block (ce_if_block_t *, int);
100 static rtx noce_get_condition (rtx, rtx *);
101 static int noce_operand_ok (rtx);
102 static int noce_process_if_block (ce_if_block_t *);
103 static int process_if_block (ce_if_block_t *);
104 static void merge_if_block (ce_if_block_t *);
105 static int find_cond_trap (basic_block, edge, edge);
106 static basic_block find_if_header (basic_block, int);
107 static int block_jumps_and_fallthru_p (basic_block, basic_block);
108 static int find_if_block (ce_if_block_t *);
109 static int find_if_case_1 (basic_block, edge, edge);
110 static int find_if_case_2 (basic_block, edge, edge);
111 static int find_memory (rtx *, void *);
112 static int dead_or_predicable (basic_block, basic_block, basic_block,
114 static void noce_emit_move_insn (rtx, rtx);
115 static rtx block_has_only_trap (basic_block);
117 /* Count the number of non-jump active insns in BB. */
120 count_bb_insns (basic_block bb)
123 rtx insn = BB_HEAD (bb);
127 if (CALL_P (insn) || NONJUMP_INSN_P (insn))
130 if (insn == BB_END (bb))
132 insn = NEXT_INSN (insn);
138 /* Determine whether the total insn_rtx_cost on non-jump insns in
139 basic block BB is less than MAX_COST. This function returns
140 false if the cost of any instruction could not be estimated. */
143 cheap_bb_rtx_cost_p (basic_block bb, int max_cost)
146 rtx insn = BB_HEAD (bb);
150 if (NONJUMP_INSN_P (insn))
152 int cost = insn_rtx_cost (PATTERN (insn));
156 /* If this instruction is the load or set of a "stack" register,
157 such as a floating point register on x87, then the cost of
158 speculatively executing this insn may need to include
159 the additional cost of popping its result off of the
160 register stack. Unfortunately, correctly recognizing and
161 accounting for this additional overhead is tricky, so for
162 now we simply prohibit such speculative execution. */
165 rtx set = single_set (insn);
166 if (set && STACK_REG_P (SET_DEST (set)))
172 if (count >= max_cost)
175 else if (CALL_P (insn))
178 if (insn == BB_END (bb))
180 insn = NEXT_INSN (insn);
186 /* Return the first non-jump active insn in the basic block. */
189 first_active_insn (basic_block bb)
191 rtx insn = BB_HEAD (bb);
195 if (insn == BB_END (bb))
197 insn = NEXT_INSN (insn);
200 while (NOTE_P (insn))
202 if (insn == BB_END (bb))
204 insn = NEXT_INSN (insn);
213 /* Return the last non-jump active (non-jump) insn in the basic block. */
216 last_active_insn (basic_block bb, int skip_use_p)
218 rtx insn = BB_END (bb);
219 rtx head = BB_HEAD (bb);
224 && NONJUMP_INSN_P (insn)
225 && GET_CODE (PATTERN (insn)) == USE))
229 insn = PREV_INSN (insn);
238 /* Return the basic block reached by falling though the basic block BB. */
241 block_fallthru (basic_block bb)
246 FOR_EACH_EDGE (e, ei, bb->succs)
247 if (e->flags & EDGE_FALLTHRU)
250 return (e) ? e->dest : NULL_BLOCK;
253 /* Go through a bunch of insns, converting them to conditional
254 execution format if possible. Return TRUE if all of the non-note
255 insns were processed. */
258 cond_exec_process_insns (ce_if_block_t *ce_info ATTRIBUTE_UNUSED,
259 /* if block information */rtx start,
260 /* first insn to look at */rtx end,
261 /* last insn to look at */rtx test,
262 /* conditional execution test */rtx prob_val,
263 /* probability of branch taken. */int mod_ok)
265 int must_be_last = FALSE;
273 for (insn = start; ; insn = NEXT_INSN (insn))
278 gcc_assert(NONJUMP_INSN_P (insn) || CALL_P (insn));
280 /* Remove USE insns that get in the way. */
281 if (reload_completed && GET_CODE (PATTERN (insn)) == USE)
283 /* ??? Ug. Actually unlinking the thing is problematic,
284 given what we'd have to coordinate with our callers. */
285 SET_INSN_DELETED (insn);
289 /* Last insn wasn't last? */
293 if (modified_in_p (test, insn))
300 /* Now build the conditional form of the instruction. */
301 pattern = PATTERN (insn);
302 xtest = copy_rtx (test);
304 /* If this is already a COND_EXEC, rewrite the test to be an AND of the
306 if (GET_CODE (pattern) == COND_EXEC)
308 if (GET_MODE (xtest) != GET_MODE (COND_EXEC_TEST (pattern)))
311 xtest = gen_rtx_AND (GET_MODE (xtest), xtest,
312 COND_EXEC_TEST (pattern));
313 pattern = COND_EXEC_CODE (pattern);
316 pattern = gen_rtx_COND_EXEC (VOIDmode, xtest, pattern);
318 /* If the machine needs to modify the insn being conditionally executed,
319 say for example to force a constant integer operand into a temp
320 register, do so here. */
321 #ifdef IFCVT_MODIFY_INSN
322 IFCVT_MODIFY_INSN (ce_info, pattern, insn);
327 validate_change (insn, &PATTERN (insn), pattern, 1);
329 if (CALL_P (insn) && prob_val)
330 validate_change (insn, ®_NOTES (insn),
331 alloc_EXPR_LIST (REG_BR_PROB, prob_val,
332 REG_NOTES (insn)), 1);
342 /* Return the condition for a jump. Do not do any special processing. */
345 cond_exec_get_condition (rtx jump)
349 if (any_condjump_p (jump))
350 test_if = SET_SRC (pc_set (jump));
353 cond = XEXP (test_if, 0);
355 /* If this branches to JUMP_LABEL when the condition is false,
356 reverse the condition. */
357 if (GET_CODE (XEXP (test_if, 2)) == LABEL_REF
358 && XEXP (XEXP (test_if, 2), 0) == JUMP_LABEL (jump))
360 enum rtx_code rev = reversed_comparison_code (cond, jump);
364 cond = gen_rtx_fmt_ee (rev, GET_MODE (cond), XEXP (cond, 0),
371 /* Given a simple IF-THEN or IF-THEN-ELSE block, attempt to convert it
372 to conditional execution. Return TRUE if we were successful at
373 converting the block. */
376 cond_exec_process_if_block (ce_if_block_t * ce_info,
377 /* if block information */int do_multiple_p)
379 basic_block test_bb = ce_info->test_bb; /* last test block */
380 basic_block then_bb = ce_info->then_bb; /* THEN */
381 basic_block else_bb = ce_info->else_bb; /* ELSE or NULL */
382 rtx test_expr; /* expression in IF_THEN_ELSE that is tested */
383 rtx then_start; /* first insn in THEN block */
384 rtx then_end; /* last insn + 1 in THEN block */
385 rtx else_start = NULL_RTX; /* first insn in ELSE block or NULL */
386 rtx else_end = NULL_RTX; /* last insn + 1 in ELSE block */
387 int max; /* max # of insns to convert. */
388 int then_mod_ok; /* whether conditional mods are ok in THEN */
389 rtx true_expr; /* test for else block insns */
390 rtx false_expr; /* test for then block insns */
391 rtx true_prob_val; /* probability of else block */
392 rtx false_prob_val; /* probability of then block */
394 enum rtx_code false_code;
396 /* If test is comprised of && or || elements, and we've failed at handling
397 all of them together, just use the last test if it is the special case of
398 && elements without an ELSE block. */
399 if (!do_multiple_p && ce_info->num_multiple_test_blocks)
401 if (else_bb || ! ce_info->and_and_p)
404 ce_info->test_bb = test_bb = ce_info->last_test_bb;
405 ce_info->num_multiple_test_blocks = 0;
406 ce_info->num_and_and_blocks = 0;
407 ce_info->num_or_or_blocks = 0;
410 /* Find the conditional jump to the ELSE or JOIN part, and isolate
412 test_expr = cond_exec_get_condition (BB_END (test_bb));
416 /* If the conditional jump is more than just a conditional jump,
417 then we can not do conditional execution conversion on this block. */
418 if (! onlyjump_p (BB_END (test_bb)))
421 /* Collect the bounds of where we're to search, skipping any labels, jumps
422 and notes at the beginning and end of the block. Then count the total
423 number of insns and see if it is small enough to convert. */
424 then_start = first_active_insn (then_bb);
425 then_end = last_active_insn (then_bb, TRUE);
426 n_insns = ce_info->num_then_insns = count_bb_insns (then_bb);
427 max = MAX_CONDITIONAL_EXECUTE;
432 else_start = first_active_insn (else_bb);
433 else_end = last_active_insn (else_bb, TRUE);
434 n_insns += ce_info->num_else_insns = count_bb_insns (else_bb);
440 /* Map test_expr/test_jump into the appropriate MD tests to use on
441 the conditionally executed code. */
443 true_expr = test_expr;
445 false_code = reversed_comparison_code (true_expr, BB_END (test_bb));
446 if (false_code != UNKNOWN)
447 false_expr = gen_rtx_fmt_ee (false_code, GET_MODE (true_expr),
448 XEXP (true_expr, 0), XEXP (true_expr, 1));
450 false_expr = NULL_RTX;
452 #ifdef IFCVT_MODIFY_TESTS
453 /* If the machine description needs to modify the tests, such as setting a
454 conditional execution register from a comparison, it can do so here. */
455 IFCVT_MODIFY_TESTS (ce_info, true_expr, false_expr);
457 /* See if the conversion failed. */
458 if (!true_expr || !false_expr)
462 true_prob_val = find_reg_note (BB_END (test_bb), REG_BR_PROB, NULL_RTX);
465 true_prob_val = XEXP (true_prob_val, 0);
466 false_prob_val = GEN_INT (REG_BR_PROB_BASE - INTVAL (true_prob_val));
469 false_prob_val = NULL_RTX;
471 /* If we have && or || tests, do them here. These tests are in the adjacent
472 blocks after the first block containing the test. */
473 if (ce_info->num_multiple_test_blocks > 0)
475 basic_block bb = test_bb;
476 basic_block last_test_bb = ce_info->last_test_bb;
485 enum rtx_code f_code;
487 bb = block_fallthru (bb);
488 start = first_active_insn (bb);
489 end = last_active_insn (bb, TRUE);
491 && ! cond_exec_process_insns (ce_info, start, end, false_expr,
492 false_prob_val, FALSE))
495 /* If the conditional jump is more than just a conditional jump, then
496 we can not do conditional execution conversion on this block. */
497 if (! onlyjump_p (BB_END (bb)))
500 /* Find the conditional jump and isolate the test. */
501 t = cond_exec_get_condition (BB_END (bb));
505 f_code = reversed_comparison_code (t, BB_END (bb));
506 if (f_code == UNKNOWN)
509 f = gen_rtx_fmt_ee (f_code, GET_MODE (t), XEXP (t, 0), XEXP (t, 1));
510 if (ce_info->and_and_p)
512 t = gen_rtx_AND (GET_MODE (t), true_expr, t);
513 f = gen_rtx_IOR (GET_MODE (t), false_expr, f);
517 t = gen_rtx_IOR (GET_MODE (t), true_expr, t);
518 f = gen_rtx_AND (GET_MODE (t), false_expr, f);
521 /* If the machine description needs to modify the tests, such as
522 setting a conditional execution register from a comparison, it can
524 #ifdef IFCVT_MODIFY_MULTIPLE_TESTS
525 IFCVT_MODIFY_MULTIPLE_TESTS (ce_info, bb, t, f);
527 /* See if the conversion failed. */
535 while (bb != last_test_bb);
538 /* For IF-THEN-ELSE blocks, we don't allow modifications of the test
539 on then THEN block. */
540 then_mod_ok = (else_bb == NULL_BLOCK);
542 /* Go through the THEN and ELSE blocks converting the insns if possible
543 to conditional execution. */
547 || ! cond_exec_process_insns (ce_info, then_start, then_end,
548 false_expr, false_prob_val,
552 if (else_bb && else_end
553 && ! cond_exec_process_insns (ce_info, else_start, else_end,
554 true_expr, true_prob_val, TRUE))
557 /* If we cannot apply the changes, fail. Do not go through the normal fail
558 processing, since apply_change_group will call cancel_changes. */
559 if (! apply_change_group ())
561 #ifdef IFCVT_MODIFY_CANCEL
562 /* Cancel any machine dependent changes. */
563 IFCVT_MODIFY_CANCEL (ce_info);
568 #ifdef IFCVT_MODIFY_FINAL
569 /* Do any machine dependent final modifications. */
570 IFCVT_MODIFY_FINAL (ce_info);
573 /* Conversion succeeded. */
575 fprintf (dump_file, "%d insn%s converted to conditional execution.\n",
576 n_insns, (n_insns == 1) ? " was" : "s were");
578 /* Merge the blocks! */
579 merge_if_block (ce_info);
580 cond_exec_changed_p = TRUE;
584 #ifdef IFCVT_MODIFY_CANCEL
585 /* Cancel any machine dependent changes. */
586 IFCVT_MODIFY_CANCEL (ce_info);
593 /* Used by noce_process_if_block to communicate with its subroutines.
595 The subroutines know that A and B may be evaluated freely. They
596 know that X is a register. They should insert new instructions
597 before cond_earliest. */
601 /* A basic block that ends in a simple conditional jump. */
604 /* The jump that ends TEST_BB. */
607 /* The jump condition. */
610 /* New insns should be inserted before this one. */
613 /* Insns in the THEN and ELSE block. There is always just this
614 one insns in those blocks. The insns are single_set insns.
615 If there was no ELSE block, INSN_B is the last insn before
616 COND_EARLIEST, or NULL_RTX. In the former case, the insn
617 operands are still valid, as if INSN_B was moved down below
621 /* The SET_SRC of INSN_A and INSN_B. */
624 /* The SET_DEST of INSN_A. */
628 static rtx noce_emit_store_flag (struct noce_if_info *, rtx, int, int);
629 static int noce_try_move (struct noce_if_info *);
630 static int noce_try_store_flag (struct noce_if_info *);
631 static int noce_try_addcc (struct noce_if_info *);
632 static int noce_try_store_flag_constants (struct noce_if_info *);
633 static int noce_try_store_flag_mask (struct noce_if_info *);
634 static rtx noce_emit_cmove (struct noce_if_info *, rtx, enum rtx_code, rtx,
636 static int noce_try_cmove (struct noce_if_info *);
637 static int noce_try_cmove_arith (struct noce_if_info *);
638 static rtx noce_get_alt_condition (struct noce_if_info *, rtx, rtx *);
639 static int noce_try_minmax (struct noce_if_info *);
640 static int noce_try_abs (struct noce_if_info *);
641 static int noce_try_sign_mask (struct noce_if_info *);
643 /* Helper function for noce_try_store_flag*. */
646 noce_emit_store_flag (struct noce_if_info *if_info, rtx x, int reversep,
649 rtx cond = if_info->cond;
653 cond_complex = (! general_operand (XEXP (cond, 0), VOIDmode)
654 || ! general_operand (XEXP (cond, 1), VOIDmode));
656 /* If earliest == jump, or when the condition is complex, try to
657 build the store_flag insn directly. */
660 cond = XEXP (SET_SRC (pc_set (if_info->jump)), 0);
663 code = reversed_comparison_code (cond, if_info->jump);
665 code = GET_CODE (cond);
667 if ((if_info->cond_earliest == if_info->jump || cond_complex)
668 && (normalize == 0 || STORE_FLAG_VALUE == normalize))
672 tmp = gen_rtx_fmt_ee (code, GET_MODE (x), XEXP (cond, 0),
674 tmp = gen_rtx_SET (VOIDmode, x, tmp);
677 tmp = emit_insn (tmp);
679 if (recog_memoized (tmp) >= 0)
685 if_info->cond_earliest = if_info->jump;
693 /* Don't even try if the comparison operands or the mode of X are weird. */
694 if (cond_complex || !SCALAR_INT_MODE_P (GET_MODE (x)))
697 return emit_store_flag (x, code, XEXP (cond, 0),
698 XEXP (cond, 1), VOIDmode,
699 (code == LTU || code == LEU
700 || code == GEU || code == GTU), normalize);
703 /* Emit instruction to move an rtx, possibly into STRICT_LOW_PART.
704 X is the destination/target and Y is the value to copy. */
707 noce_emit_move_insn (rtx x, rtx y)
709 enum machine_mode outmode;
713 if (GET_CODE (x) != STRICT_LOW_PART)
715 rtx seq, insn, target;
719 /* Check that the SET_SRC is reasonable before calling emit_move_insn,
720 otherwise construct a suitable SET pattern ourselves. */
721 insn = (OBJECT_P (y) || CONSTANT_P (y) || GET_CODE (y) == SUBREG)
722 ? emit_move_insn (x, y)
723 : emit_insn (gen_rtx_SET (VOIDmode, x, y));
727 if (recog_memoized (insn) <= 0)
729 if (GET_CODE (x) == ZERO_EXTRACT)
731 rtx op = XEXP (x, 0);
732 unsigned HOST_WIDE_INT size = INTVAL (XEXP (x, 1));
733 unsigned HOST_WIDE_INT start = INTVAL (XEXP (x, 2));
735 /* store_bit_field expects START to be relative to
736 BYTES_BIG_ENDIAN and adjusts this value for machines with
737 BITS_BIG_ENDIAN != BYTES_BIG_ENDIAN. In order to be able to
738 invoke store_bit_field again it is necessary to have the START
739 value from the first call. */
740 if (BITS_BIG_ENDIAN != BYTES_BIG_ENDIAN)
743 start = BITS_PER_UNIT - start - size;
746 gcc_assert (REG_P (op));
747 start = BITS_PER_WORD - start - size;
751 gcc_assert (start < (MEM_P (op) ? BITS_PER_UNIT : BITS_PER_WORD));
752 store_bit_field (op, size, start, GET_MODE (x), y);
756 switch (GET_RTX_CLASS (GET_CODE (y)))
759 ot = code_to_optab[GET_CODE (y)];
763 target = expand_unop (GET_MODE (y), ot, XEXP (y, 0), x, 0);
764 if (target != NULL_RTX)
767 emit_move_insn (x, target);
776 ot = code_to_optab[GET_CODE (y)];
780 target = expand_binop (GET_MODE (y), ot,
781 XEXP (y, 0), XEXP (y, 1),
783 if (target != NULL_RTX)
786 emit_move_insn (x, target);
803 inner = XEXP (outer, 0);
804 outmode = GET_MODE (outer);
805 bitpos = SUBREG_BYTE (outer) * BITS_PER_UNIT;
806 store_bit_field (inner, GET_MODE_BITSIZE (outmode), bitpos, outmode, y);
809 /* Return sequence of instructions generated by if conversion. This
810 function calls end_sequence() to end the current stream, ensures
811 that are instructions are unshared, recognizable non-jump insns.
812 On failure, this function returns a NULL_RTX. */
815 end_ifcvt_sequence (struct noce_if_info *if_info)
818 rtx seq = get_insns ();
820 set_used_flags (if_info->x);
821 set_used_flags (if_info->cond);
822 unshare_all_rtl_in_chain (seq);
825 /* Make sure that all of the instructions emitted are recognizable,
826 and that we haven't introduced a new jump instruction.
827 As an exercise for the reader, build a general mechanism that
828 allows proper placement of required clobbers. */
829 for (insn = seq; insn; insn = NEXT_INSN (insn))
831 || recog_memoized (insn) == -1)
837 /* Convert "if (a != b) x = a; else x = b" into "x = a" and
838 "if (a == b) x = a; else x = b" into "x = b". */
841 noce_try_move (struct noce_if_info *if_info)
843 rtx cond = if_info->cond;
844 enum rtx_code code = GET_CODE (cond);
847 if (code != NE && code != EQ)
850 /* This optimization isn't valid if either A or B could be a NaN
852 if (HONOR_NANS (GET_MODE (if_info->x))
853 || HONOR_SIGNED_ZEROS (GET_MODE (if_info->x)))
856 /* Check whether the operands of the comparison are A and in
858 if ((rtx_equal_p (if_info->a, XEXP (cond, 0))
859 && rtx_equal_p (if_info->b, XEXP (cond, 1)))
860 || (rtx_equal_p (if_info->a, XEXP (cond, 1))
861 && rtx_equal_p (if_info->b, XEXP (cond, 0))))
863 y = (code == EQ) ? if_info->a : if_info->b;
865 /* Avoid generating the move if the source is the destination. */
866 if (! rtx_equal_p (if_info->x, y))
869 noce_emit_move_insn (if_info->x, y);
870 seq = end_ifcvt_sequence (if_info);
874 emit_insn_before_setloc (seq, if_info->jump,
875 INSN_LOCATOR (if_info->insn_a));
882 /* Convert "if (test) x = 1; else x = 0".
884 Only try 0 and STORE_FLAG_VALUE here. Other combinations will be
885 tried in noce_try_store_flag_constants after noce_try_cmove has had
886 a go at the conversion. */
889 noce_try_store_flag (struct noce_if_info *if_info)
894 if (GET_CODE (if_info->b) == CONST_INT
895 && INTVAL (if_info->b) == STORE_FLAG_VALUE
896 && if_info->a == const0_rtx)
898 else if (if_info->b == const0_rtx
899 && GET_CODE (if_info->a) == CONST_INT
900 && INTVAL (if_info->a) == STORE_FLAG_VALUE
901 && (reversed_comparison_code (if_info->cond, if_info->jump)
909 target = noce_emit_store_flag (if_info, if_info->x, reversep, 0);
912 if (target != if_info->x)
913 noce_emit_move_insn (if_info->x, target);
915 seq = end_ifcvt_sequence (if_info);
919 emit_insn_before_setloc (seq, if_info->jump,
920 INSN_LOCATOR (if_info->insn_a));
930 /* Convert "if (test) x = a; else x = b", for A and B constant. */
933 noce_try_store_flag_constants (struct noce_if_info *if_info)
937 HOST_WIDE_INT itrue, ifalse, diff, tmp;
938 int normalize, can_reverse;
939 enum machine_mode mode;
942 && GET_CODE (if_info->a) == CONST_INT
943 && GET_CODE (if_info->b) == CONST_INT)
945 mode = GET_MODE (if_info->x);
946 ifalse = INTVAL (if_info->a);
947 itrue = INTVAL (if_info->b);
949 /* Make sure we can represent the difference between the two values. */
950 if ((itrue - ifalse > 0)
951 != ((ifalse < 0) != (itrue < 0) ? ifalse < 0 : ifalse < itrue))
954 diff = trunc_int_for_mode (itrue - ifalse, mode);
956 can_reverse = (reversed_comparison_code (if_info->cond, if_info->jump)
960 if (diff == STORE_FLAG_VALUE || diff == -STORE_FLAG_VALUE)
962 else if (ifalse == 0 && exact_log2 (itrue) >= 0
963 && (STORE_FLAG_VALUE == 1
964 || BRANCH_COST >= 2))
966 else if (itrue == 0 && exact_log2 (ifalse) >= 0 && can_reverse
967 && (STORE_FLAG_VALUE == 1 || BRANCH_COST >= 2))
968 normalize = 1, reversep = 1;
970 && (STORE_FLAG_VALUE == -1
971 || BRANCH_COST >= 2))
973 else if (ifalse == -1 && can_reverse
974 && (STORE_FLAG_VALUE == -1 || BRANCH_COST >= 2))
975 normalize = -1, reversep = 1;
976 else if ((BRANCH_COST >= 2 && STORE_FLAG_VALUE == -1)
984 tmp = itrue; itrue = ifalse; ifalse = tmp;
985 diff = trunc_int_for_mode (-diff, mode);
989 target = noce_emit_store_flag (if_info, if_info->x, reversep, normalize);
996 /* if (test) x = 3; else x = 4;
997 => x = 3 + (test == 0); */
998 if (diff == STORE_FLAG_VALUE || diff == -STORE_FLAG_VALUE)
1000 target = expand_simple_binop (mode,
1001 (diff == STORE_FLAG_VALUE
1003 GEN_INT (ifalse), target, if_info->x, 0,
1007 /* if (test) x = 8; else x = 0;
1008 => x = (test != 0) << 3; */
1009 else if (ifalse == 0 && (tmp = exact_log2 (itrue)) >= 0)
1011 target = expand_simple_binop (mode, ASHIFT,
1012 target, GEN_INT (tmp), if_info->x, 0,
1016 /* if (test) x = -1; else x = b;
1017 => x = -(test != 0) | b; */
1018 else if (itrue == -1)
1020 target = expand_simple_binop (mode, IOR,
1021 target, GEN_INT (ifalse), if_info->x, 0,
1025 /* if (test) x = a; else x = b;
1026 => x = (-(test != 0) & (b - a)) + a; */
1029 target = expand_simple_binop (mode, AND,
1030 target, GEN_INT (diff), if_info->x, 0,
1033 target = expand_simple_binop (mode, PLUS,
1034 target, GEN_INT (ifalse),
1035 if_info->x, 0, OPTAB_WIDEN);
1044 if (target != if_info->x)
1045 noce_emit_move_insn (if_info->x, target);
1047 seq = end_ifcvt_sequence (if_info);
1051 emit_insn_before_setloc (seq, if_info->jump,
1052 INSN_LOCATOR (if_info->insn_a));
1059 /* Convert "if (test) foo++" into "foo += (test != 0)", and
1060 similarly for "foo--". */
1063 noce_try_addcc (struct noce_if_info *if_info)
1066 int subtract, normalize;
1068 if (! no_new_pseudos
1069 && GET_CODE (if_info->a) == PLUS
1070 && rtx_equal_p (XEXP (if_info->a, 0), if_info->b)
1071 && (reversed_comparison_code (if_info->cond, if_info->jump)
1074 rtx cond = if_info->cond;
1075 enum rtx_code code = reversed_comparison_code (cond, if_info->jump);
1077 /* First try to use addcc pattern. */
1078 if (general_operand (XEXP (cond, 0), VOIDmode)
1079 && general_operand (XEXP (cond, 1), VOIDmode))
1082 target = emit_conditional_add (if_info->x, code,
1087 XEXP (if_info->a, 1),
1088 GET_MODE (if_info->x),
1089 (code == LTU || code == GEU
1090 || code == LEU || code == GTU));
1093 if (target != if_info->x)
1094 noce_emit_move_insn (if_info->x, target);
1096 seq = end_ifcvt_sequence (if_info);
1100 emit_insn_before_setloc (seq, if_info->jump,
1101 INSN_LOCATOR (if_info->insn_a));
1107 /* If that fails, construct conditional increment or decrement using
1109 if (BRANCH_COST >= 2
1110 && (XEXP (if_info->a, 1) == const1_rtx
1111 || XEXP (if_info->a, 1) == constm1_rtx))
1114 if (STORE_FLAG_VALUE == INTVAL (XEXP (if_info->a, 1)))
1115 subtract = 0, normalize = 0;
1116 else if (-STORE_FLAG_VALUE == INTVAL (XEXP (if_info->a, 1)))
1117 subtract = 1, normalize = 0;
1119 subtract = 0, normalize = INTVAL (XEXP (if_info->a, 1));
1122 target = noce_emit_store_flag (if_info,
1123 gen_reg_rtx (GET_MODE (if_info->x)),
1127 target = expand_simple_binop (GET_MODE (if_info->x),
1128 subtract ? MINUS : PLUS,
1129 if_info->b, target, if_info->x,
1133 if (target != if_info->x)
1134 noce_emit_move_insn (if_info->x, target);
1136 seq = end_ifcvt_sequence (if_info);
1140 emit_insn_before_setloc (seq, if_info->jump,
1141 INSN_LOCATOR (if_info->insn_a));
1151 /* Convert "if (test) x = 0;" to "x &= -(test == 0);" */
1154 noce_try_store_flag_mask (struct noce_if_info *if_info)
1160 if (! no_new_pseudos
1161 && (BRANCH_COST >= 2
1162 || STORE_FLAG_VALUE == -1)
1163 && ((if_info->a == const0_rtx
1164 && rtx_equal_p (if_info->b, if_info->x))
1165 || ((reversep = (reversed_comparison_code (if_info->cond,
1168 && if_info->b == const0_rtx
1169 && rtx_equal_p (if_info->a, if_info->x))))
1172 target = noce_emit_store_flag (if_info,
1173 gen_reg_rtx (GET_MODE (if_info->x)),
1176 target = expand_simple_binop (GET_MODE (if_info->x), AND,
1178 target, if_info->x, 0,
1183 if (target != if_info->x)
1184 noce_emit_move_insn (if_info->x, target);
1186 seq = end_ifcvt_sequence (if_info);
1190 emit_insn_before_setloc (seq, if_info->jump,
1191 INSN_LOCATOR (if_info->insn_a));
1201 /* Helper function for noce_try_cmove and noce_try_cmove_arith. */
1204 noce_emit_cmove (struct noce_if_info *if_info, rtx x, enum rtx_code code,
1205 rtx cmp_a, rtx cmp_b, rtx vfalse, rtx vtrue)
1207 /* If earliest == jump, try to build the cmove insn directly.
1208 This is helpful when combine has created some complex condition
1209 (like for alpha's cmovlbs) that we can't hope to regenerate
1210 through the normal interface. */
1212 if (if_info->cond_earliest == if_info->jump)
1216 tmp = gen_rtx_fmt_ee (code, GET_MODE (if_info->cond), cmp_a, cmp_b);
1217 tmp = gen_rtx_IF_THEN_ELSE (GET_MODE (x), tmp, vtrue, vfalse);
1218 tmp = gen_rtx_SET (VOIDmode, x, tmp);
1221 tmp = emit_insn (tmp);
1223 if (recog_memoized (tmp) >= 0)
1235 /* Don't even try if the comparison operands are weird. */
1236 if (! general_operand (cmp_a, GET_MODE (cmp_a))
1237 || ! general_operand (cmp_b, GET_MODE (cmp_b)))
1240 #if HAVE_conditional_move
1241 return emit_conditional_move (x, code, cmp_a, cmp_b, VOIDmode,
1242 vtrue, vfalse, GET_MODE (x),
1243 (code == LTU || code == GEU
1244 || code == LEU || code == GTU));
1246 /* We'll never get here, as noce_process_if_block doesn't call the
1247 functions involved. Ifdef code, however, should be discouraged
1248 because it leads to typos in the code not selected. However,
1249 emit_conditional_move won't exist either. */
1254 /* Try only simple constants and registers here. More complex cases
1255 are handled in noce_try_cmove_arith after noce_try_store_flag_arith
1256 has had a go at it. */
1259 noce_try_cmove (struct noce_if_info *if_info)
1264 if ((CONSTANT_P (if_info->a) || register_operand (if_info->a, VOIDmode))
1265 && (CONSTANT_P (if_info->b) || register_operand (if_info->b, VOIDmode)))
1269 code = GET_CODE (if_info->cond);
1270 target = noce_emit_cmove (if_info, if_info->x, code,
1271 XEXP (if_info->cond, 0),
1272 XEXP (if_info->cond, 1),
1273 if_info->a, if_info->b);
1277 if (target != if_info->x)
1278 noce_emit_move_insn (if_info->x, target);
1280 seq = end_ifcvt_sequence (if_info);
1284 emit_insn_before_setloc (seq, if_info->jump,
1285 INSN_LOCATOR (if_info->insn_a));
1298 /* Try more complex cases involving conditional_move. */
1301 noce_try_cmove_arith (struct noce_if_info *if_info)
1313 /* A conditional move from two memory sources is equivalent to a
1314 conditional on their addresses followed by a load. Don't do this
1315 early because it'll screw alias analysis. Note that we've
1316 already checked for no side effects. */
1317 if (! no_new_pseudos && cse_not_expected
1318 && MEM_P (a) && MEM_P (b)
1319 && BRANCH_COST >= 5)
1323 x = gen_reg_rtx (Pmode);
1327 /* ??? We could handle this if we knew that a load from A or B could
1328 not fault. This is also true if we've already loaded
1329 from the address along the path from ENTRY. */
1330 else if (may_trap_p (a) || may_trap_p (b))
1333 /* if (test) x = a + b; else x = c - d;
1340 code = GET_CODE (if_info->cond);
1341 insn_a = if_info->insn_a;
1342 insn_b = if_info->insn_b;
1344 /* Total insn_rtx_cost should be smaller than branch cost. Exit
1345 if insn_rtx_cost can't be estimated. */
1348 insn_cost = insn_rtx_cost (PATTERN (insn_a));
1349 if (insn_cost == 0 || insn_cost > COSTS_N_INSNS (BRANCH_COST))
1357 insn_cost += insn_rtx_cost (PATTERN (insn_b));
1358 if (insn_cost == 0 || insn_cost > COSTS_N_INSNS (BRANCH_COST))
1362 /* Possibly rearrange operands to make things come out more natural. */
1363 if (reversed_comparison_code (if_info->cond, if_info->jump) != UNKNOWN)
1366 if (rtx_equal_p (b, x))
1368 else if (general_operand (b, GET_MODE (b)))
1373 code = reversed_comparison_code (if_info->cond, if_info->jump);
1374 tmp = a, a = b, b = tmp;
1375 tmp = insn_a, insn_a = insn_b, insn_b = tmp;
1384 /* If either operand is complex, load it into a register first.
1385 The best way to do this is to copy the original insn. In this
1386 way we preserve any clobbers etc that the insn may have had.
1387 This is of course not possible in the IS_MEM case. */
1388 if (! general_operand (a, GET_MODE (a)))
1393 goto end_seq_and_fail;
1397 tmp = gen_reg_rtx (GET_MODE (a));
1398 tmp = emit_insn (gen_rtx_SET (VOIDmode, tmp, a));
1401 goto end_seq_and_fail;
1404 a = gen_reg_rtx (GET_MODE (a));
1405 tmp = copy_rtx (insn_a);
1406 set = single_set (tmp);
1408 tmp = emit_insn (PATTERN (tmp));
1410 if (recog_memoized (tmp) < 0)
1411 goto end_seq_and_fail;
1413 if (! general_operand (b, GET_MODE (b)))
1418 goto end_seq_and_fail;
1422 tmp = gen_reg_rtx (GET_MODE (b));
1423 tmp = gen_rtx_SET (VOIDmode, tmp, b);
1426 goto end_seq_and_fail;
1429 b = gen_reg_rtx (GET_MODE (b));
1430 tmp = copy_rtx (insn_b);
1431 set = single_set (tmp);
1433 tmp = PATTERN (tmp);
1436 /* If insn to set up A clobbers any registers B depends on, try to
1437 swap insn that sets up A with the one that sets up B. If even
1438 that doesn't help, punt. */
1439 last = get_last_insn ();
1440 if (last && modified_in_p (orig_b, last))
1442 tmp = emit_insn_before (tmp, get_insns ());
1443 if (modified_in_p (orig_a, tmp))
1444 goto end_seq_and_fail;
1447 tmp = emit_insn (tmp);
1449 if (recog_memoized (tmp) < 0)
1450 goto end_seq_and_fail;
1453 target = noce_emit_cmove (if_info, x, code, XEXP (if_info->cond, 0),
1454 XEXP (if_info->cond, 1), a, b);
1457 goto end_seq_and_fail;
1459 /* If we're handling a memory for above, emit the load now. */
1462 tmp = gen_rtx_MEM (GET_MODE (if_info->x), target);
1464 /* Copy over flags as appropriate. */
1465 if (MEM_VOLATILE_P (if_info->a) || MEM_VOLATILE_P (if_info->b))
1466 MEM_VOLATILE_P (tmp) = 1;
1467 if (MEM_IN_STRUCT_P (if_info->a) && MEM_IN_STRUCT_P (if_info->b))
1468 MEM_IN_STRUCT_P (tmp) = 1;
1469 if (MEM_SCALAR_P (if_info->a) && MEM_SCALAR_P (if_info->b))
1470 MEM_SCALAR_P (tmp) = 1;
1471 if (MEM_ALIAS_SET (if_info->a) == MEM_ALIAS_SET (if_info->b))
1472 set_mem_alias_set (tmp, MEM_ALIAS_SET (if_info->a));
1474 MIN (MEM_ALIGN (if_info->a), MEM_ALIGN (if_info->b)));
1476 noce_emit_move_insn (if_info->x, tmp);
1478 else if (target != x)
1479 noce_emit_move_insn (x, target);
1481 tmp = end_ifcvt_sequence (if_info);
1485 emit_insn_before_setloc (tmp, if_info->jump, INSN_LOCATOR (if_info->insn_a));
1493 /* For most cases, the simplified condition we found is the best
1494 choice, but this is not the case for the min/max/abs transforms.
1495 For these we wish to know that it is A or B in the condition. */
1498 noce_get_alt_condition (struct noce_if_info *if_info, rtx target,
1501 rtx cond, set, insn;
1504 /* If target is already mentioned in the known condition, return it. */
1505 if (reg_mentioned_p (target, if_info->cond))
1507 *earliest = if_info->cond_earliest;
1508 return if_info->cond;
1511 set = pc_set (if_info->jump);
1512 cond = XEXP (SET_SRC (set), 0);
1514 = GET_CODE (XEXP (SET_SRC (set), 2)) == LABEL_REF
1515 && XEXP (XEXP (SET_SRC (set), 2), 0) == JUMP_LABEL (if_info->jump);
1517 /* If we're looking for a constant, try to make the conditional
1518 have that constant in it. There are two reasons why it may
1519 not have the constant we want:
1521 1. GCC may have needed to put the constant in a register, because
1522 the target can't compare directly against that constant. For
1523 this case, we look for a SET immediately before the comparison
1524 that puts a constant in that register.
1526 2. GCC may have canonicalized the conditional, for example
1527 replacing "if x < 4" with "if x <= 3". We can undo that (or
1528 make equivalent types of changes) to get the constants we need
1529 if they're off by one in the right direction. */
1531 if (GET_CODE (target) == CONST_INT)
1533 enum rtx_code code = GET_CODE (if_info->cond);
1534 rtx op_a = XEXP (if_info->cond, 0);
1535 rtx op_b = XEXP (if_info->cond, 1);
1538 /* First, look to see if we put a constant in a register. */
1539 prev_insn = prev_nonnote_insn (if_info->cond_earliest);
1541 && INSN_P (prev_insn)
1542 && GET_CODE (PATTERN (prev_insn)) == SET)
1544 rtx src = find_reg_equal_equiv_note (prev_insn);
1546 src = SET_SRC (PATTERN (prev_insn));
1547 if (GET_CODE (src) == CONST_INT)
1549 if (rtx_equal_p (op_a, SET_DEST (PATTERN (prev_insn))))
1551 else if (rtx_equal_p (op_b, SET_DEST (PATTERN (prev_insn))))
1554 if (GET_CODE (op_a) == CONST_INT)
1559 code = swap_condition (code);
1564 /* Now, look to see if we can get the right constant by
1565 adjusting the conditional. */
1566 if (GET_CODE (op_b) == CONST_INT)
1568 HOST_WIDE_INT desired_val = INTVAL (target);
1569 HOST_WIDE_INT actual_val = INTVAL (op_b);
1574 if (actual_val == desired_val + 1)
1577 op_b = GEN_INT (desired_val);
1581 if (actual_val == desired_val - 1)
1584 op_b = GEN_INT (desired_val);
1588 if (actual_val == desired_val - 1)
1591 op_b = GEN_INT (desired_val);
1595 if (actual_val == desired_val + 1)
1598 op_b = GEN_INT (desired_val);
1606 /* If we made any changes, generate a new conditional that is
1607 equivalent to what we started with, but has the right
1609 if (code != GET_CODE (if_info->cond)
1610 || op_a != XEXP (if_info->cond, 0)
1611 || op_b != XEXP (if_info->cond, 1))
1613 cond = gen_rtx_fmt_ee (code, GET_MODE (cond), op_a, op_b);
1614 *earliest = if_info->cond_earliest;
1619 cond = canonicalize_condition (if_info->jump, cond, reverse,
1620 earliest, target, false, true);
1621 if (! cond || ! reg_mentioned_p (target, cond))
1624 /* We almost certainly searched back to a different place.
1625 Need to re-verify correct lifetimes. */
1627 /* X may not be mentioned in the range (cond_earliest, jump]. */
1628 for (insn = if_info->jump; insn != *earliest; insn = PREV_INSN (insn))
1629 if (INSN_P (insn) && reg_overlap_mentioned_p (if_info->x, PATTERN (insn)))
1632 /* A and B may not be modified in the range [cond_earliest, jump). */
1633 for (insn = *earliest; insn != if_info->jump; insn = NEXT_INSN (insn))
1635 && (modified_in_p (if_info->a, insn)
1636 || modified_in_p (if_info->b, insn)))
1642 /* Convert "if (a < b) x = a; else x = b;" to "x = min(a, b);", etc. */
1645 noce_try_minmax (struct noce_if_info *if_info)
1647 rtx cond, earliest, target, seq;
1648 enum rtx_code code, op;
1651 /* ??? Can't guarantee that expand_binop won't create pseudos. */
1655 /* ??? Reject modes with NaNs or signed zeros since we don't know how
1656 they will be resolved with an SMIN/SMAX. It wouldn't be too hard
1657 to get the target to tell us... */
1658 if (HONOR_SIGNED_ZEROS (GET_MODE (if_info->x))
1659 || HONOR_NANS (GET_MODE (if_info->x)))
1662 cond = noce_get_alt_condition (if_info, if_info->a, &earliest);
1666 /* Verify the condition is of the form we expect, and canonicalize
1667 the comparison code. */
1668 code = GET_CODE (cond);
1669 if (rtx_equal_p (XEXP (cond, 0), if_info->a))
1671 if (! rtx_equal_p (XEXP (cond, 1), if_info->b))
1674 else if (rtx_equal_p (XEXP (cond, 1), if_info->a))
1676 if (! rtx_equal_p (XEXP (cond, 0), if_info->b))
1678 code = swap_condition (code);
1683 /* Determine what sort of operation this is. Note that the code is for
1684 a taken branch, so the code->operation mapping appears backwards. */
1717 target = expand_simple_binop (GET_MODE (if_info->x), op,
1718 if_info->a, if_info->b,
1719 if_info->x, unsignedp, OPTAB_WIDEN);
1725 if (target != if_info->x)
1726 noce_emit_move_insn (if_info->x, target);
1728 seq = end_ifcvt_sequence (if_info);
1732 emit_insn_before_setloc (seq, if_info->jump, INSN_LOCATOR (if_info->insn_a));
1733 if_info->cond = cond;
1734 if_info->cond_earliest = earliest;
1739 /* Convert "if (a < 0) x = -a; else x = a;" to "x = abs(a);", etc. */
1742 noce_try_abs (struct noce_if_info *if_info)
1744 rtx cond, earliest, target, seq, a, b, c;
1747 /* ??? Can't guarantee that expand_binop won't create pseudos. */
1751 /* Recognize A and B as constituting an ABS or NABS. The canonical
1752 form is a branch around the negation, taken when the object is the
1753 first operand of a comparison against 0 that evaluates to true. */
1756 if (GET_CODE (a) == NEG && rtx_equal_p (XEXP (a, 0), b))
1758 else if (GET_CODE (b) == NEG && rtx_equal_p (XEXP (b, 0), a))
1760 c = a; a = b; b = c;
1766 cond = noce_get_alt_condition (if_info, b, &earliest);
1770 /* Verify the condition is of the form we expect. */
1771 if (rtx_equal_p (XEXP (cond, 0), b))
1773 else if (rtx_equal_p (XEXP (cond, 1), b))
1781 /* Verify that C is zero. Search one step backward for a
1782 REG_EQUAL note or a simple source if necessary. */
1785 rtx set, insn = prev_nonnote_insn (earliest);
1787 && (set = single_set (insn))
1788 && rtx_equal_p (SET_DEST (set), c))
1790 rtx note = find_reg_equal_equiv_note (insn);
1800 && GET_CODE (XEXP (c, 0)) == SYMBOL_REF
1801 && CONSTANT_POOL_ADDRESS_P (XEXP (c, 0)))
1802 c = get_pool_constant (XEXP (c, 0));
1804 /* Work around funny ideas get_condition has wrt canonicalization.
1805 Note that these rtx constants are known to be CONST_INT, and
1806 therefore imply integer comparisons. */
1807 if (c == constm1_rtx && GET_CODE (cond) == GT)
1809 else if (c == const1_rtx && GET_CODE (cond) == LT)
1811 else if (c != CONST0_RTX (GET_MODE (b)))
1814 /* Determine what sort of operation this is. */
1815 switch (GET_CODE (cond))
1834 target = expand_abs_nojump (GET_MODE (if_info->x), b, if_info->x, 1);
1836 /* ??? It's a quandary whether cmove would be better here, especially
1837 for integers. Perhaps combine will clean things up. */
1838 if (target && negate)
1839 target = expand_simple_unop (GET_MODE (target), NEG, target, if_info->x, 0);
1847 if (target != if_info->x)
1848 noce_emit_move_insn (if_info->x, target);
1850 seq = end_ifcvt_sequence (if_info);
1854 emit_insn_before_setloc (seq, if_info->jump, INSN_LOCATOR (if_info->insn_a));
1855 if_info->cond = cond;
1856 if_info->cond_earliest = earliest;
1861 /* Convert "if (m < 0) x = b; else x = 0;" to "x = (m >> C) & b;". */
1864 noce_try_sign_mask (struct noce_if_info *if_info)
1866 rtx cond, t, m, c, seq;
1867 enum machine_mode mode;
1869 bool b_unconditional;
1874 cond = if_info->cond;
1875 code = GET_CODE (cond);
1880 if (if_info->a == const0_rtx)
1882 if ((code == LT && c == const0_rtx)
1883 || (code == LE && c == constm1_rtx))
1886 else if (if_info->b == const0_rtx)
1888 if ((code == GE && c == const0_rtx)
1889 || (code == GT && c == constm1_rtx))
1893 if (! t || side_effects_p (t))
1896 /* We currently don't handle different modes. */
1897 mode = GET_MODE (t);
1898 if (GET_MODE (m) != mode)
1901 /* This is only profitable if T is cheap, or T is unconditionally
1902 executed/evaluated in the original insn sequence. The latter
1903 happens if INSN_B was taken from TEST_BB, or if there was no
1904 INSN_B which can happen for e.g. conditional stores to memory. */
1905 b_unconditional = (if_info->insn_b == NULL_RTX
1906 || BLOCK_FOR_INSN (if_info->insn_b) == if_info->test_bb);
1907 if (rtx_cost (t, SET) >= COSTS_N_INSNS (2)
1908 && (!b_unconditional
1909 || t != if_info->b))
1913 /* Use emit_store_flag to generate "m < 0 ? -1 : 0" instead of expanding
1914 "(signed) m >> 31" directly. This benefits targets with specialized
1915 insns to obtain the signmask, but still uses ashr_optab otherwise. */
1916 m = emit_store_flag (gen_reg_rtx (mode), LT, m, const0_rtx, mode, 0, -1);
1917 t = m ? expand_binop (mode, and_optab, m, t, NULL_RTX, 0, OPTAB_DIRECT)
1926 noce_emit_move_insn (if_info->x, t);
1928 seq = end_ifcvt_sequence (if_info);
1932 emit_insn_before_setloc (seq, if_info->jump, INSN_LOCATOR (if_info->insn_a));
1937 /* Optimize away "if (x & C) x |= C" and similar bit manipulation
1941 noce_try_bitop (struct noce_if_info *if_info)
1943 rtx cond, x, a, result, seq;
1944 enum machine_mode mode;
1949 cond = if_info->cond;
1950 code = GET_CODE (cond);
1952 /* Check for no else condition. */
1953 if (! rtx_equal_p (x, if_info->b))
1956 /* Check for a suitable condition. */
1957 if (code != NE && code != EQ)
1959 if (XEXP (cond, 1) != const0_rtx)
1961 cond = XEXP (cond, 0);
1963 /* ??? We could also handle AND here. */
1964 if (GET_CODE (cond) == ZERO_EXTRACT)
1966 if (XEXP (cond, 1) != const1_rtx
1967 || GET_CODE (XEXP (cond, 2)) != CONST_INT
1968 || ! rtx_equal_p (x, XEXP (cond, 0)))
1970 bitnum = INTVAL (XEXP (cond, 2));
1971 mode = GET_MODE (x);
1972 if (BITS_BIG_ENDIAN)
1973 bitnum = GET_MODE_BITSIZE (mode) - 1 - bitnum;
1974 if (bitnum < 0 || bitnum >= HOST_BITS_PER_WIDE_INT)
1981 if (GET_CODE (a) == IOR || GET_CODE (a) == XOR)
1983 /* Check for "if (X & C) x = x op C". */
1984 if (! rtx_equal_p (x, XEXP (a, 0))
1985 || GET_CODE (XEXP (a, 1)) != CONST_INT
1986 || (INTVAL (XEXP (a, 1)) & GET_MODE_MASK (mode))
1987 != (unsigned HOST_WIDE_INT) 1 << bitnum)
1990 /* if ((x & C) == 0) x |= C; is transformed to x |= C. */
1991 /* if ((x & C) != 0) x |= C; is transformed to nothing. */
1992 if (GET_CODE (a) == IOR)
1993 result = (code == NE) ? a : NULL_RTX;
1994 else if (code == NE)
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 (IOR, mode, x, result);
2002 /* if ((x & C) != 0) x ^= C; is transformed to x &= ~C. */
2003 result = gen_int_mode (~((HOST_WIDE_INT) 1 << bitnum), mode);
2004 result = simplify_gen_binary (AND, mode, x, result);
2007 else if (GET_CODE (a) == AND)
2009 /* Check for "if (X & C) x &= ~C". */
2010 if (! rtx_equal_p (x, XEXP (a, 0))
2011 || GET_CODE (XEXP (a, 1)) != CONST_INT
2012 || (INTVAL (XEXP (a, 1)) & GET_MODE_MASK (mode))
2013 != (~((HOST_WIDE_INT) 1 << bitnum) & GET_MODE_MASK (mode)))
2016 /* if ((x & C) == 0) x &= ~C; is transformed to nothing. */
2017 /* if ((x & C) != 0) x &= ~C; is transformed to x &= ~C. */
2018 result = (code == EQ) ? a : NULL_RTX;
2026 noce_emit_move_insn (x, result);
2027 seq = end_ifcvt_sequence (if_info);
2031 emit_insn_before_setloc (seq, if_info->jump,
2032 INSN_LOCATOR (if_info->insn_a));
2038 /* Similar to get_condition, only the resulting condition must be
2039 valid at JUMP, instead of at EARLIEST. */
2042 noce_get_condition (rtx jump, rtx *earliest)
2047 if (! any_condjump_p (jump))
2050 set = pc_set (jump);
2052 /* If this branches to JUMP_LABEL when the condition is false,
2053 reverse the condition. */
2054 reverse = (GET_CODE (XEXP (SET_SRC (set), 2)) == LABEL_REF
2055 && XEXP (XEXP (SET_SRC (set), 2), 0) == JUMP_LABEL (jump));
2057 /* If the condition variable is a register and is MODE_INT, accept it. */
2059 cond = XEXP (SET_SRC (set), 0);
2060 tmp = XEXP (cond, 0);
2061 if (REG_P (tmp) && GET_MODE_CLASS (GET_MODE (tmp)) == MODE_INT)
2066 cond = gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond)),
2067 GET_MODE (cond), tmp, XEXP (cond, 1));
2071 /* Otherwise, fall back on canonicalize_condition to do the dirty
2072 work of manipulating MODE_CC values and COMPARE rtx codes. */
2073 return canonicalize_condition (jump, cond, reverse, earliest,
2074 NULL_RTX, false, true);
2077 /* Initialize for a simple IF-THEN or IF-THEN-ELSE block. We will not
2078 be using conditional execution. Set some fields of IF_INFO based
2079 on CE_INFO: test_bb, cond, jump, cond_earliest. Return TRUE if
2083 noce_init_if_info (struct ce_if_block *ce_info, struct noce_if_info *if_info)
2085 basic_block test_bb = ce_info->test_bb;
2088 /* If test is comprised of && or || elements, don't handle it unless
2089 it is the special case of && elements without an ELSE block. */
2090 if (ce_info->num_multiple_test_blocks)
2092 if (ce_info->else_bb || !ce_info->and_and_p)
2095 ce_info->test_bb = test_bb = ce_info->last_test_bb;
2096 ce_info->num_multiple_test_blocks = 0;
2097 ce_info->num_and_and_blocks = 0;
2098 ce_info->num_or_or_blocks = 0;
2101 /* If this is not a standard conditional jump, we can't parse it. */
2102 jump = BB_END (test_bb);
2103 cond = noce_get_condition (jump, &if_info->cond_earliest);
2107 /* If the conditional jump is more than just a conditional
2108 jump, then we can not do if-conversion on this block. */
2109 if (! onlyjump_p (jump))
2112 /* We must be comparing objects whose modes imply the size. */
2113 if (GET_MODE (XEXP (cond, 0)) == BLKmode)
2116 if_info->test_bb = test_bb;
2117 if_info->cond = cond;
2118 if_info->jump = jump;
2123 /* Return true if OP is ok for if-then-else processing. */
2126 noce_operand_ok (rtx op)
2128 /* We special-case memories, so handle any of them with
2129 no address side effects. */
2131 return ! side_effects_p (XEXP (op, 0));
2133 if (side_effects_p (op))
2136 return ! may_trap_p (op);
2139 /* Return true if a write into MEM may trap or fault. */
2142 noce_mem_write_may_trap_or_fault_p (rtx mem)
2146 if (MEM_READONLY_P (mem))
2149 if (may_trap_or_fault_p (mem))
2152 addr = XEXP (mem, 0);
2154 /* Call target hook to avoid the effects of -fpic etc.... */
2155 addr = targetm.delegitimize_address (addr);
2158 switch (GET_CODE (addr))
2166 addr = XEXP (addr, 0);
2170 addr = XEXP (addr, 1);
2173 if (GET_CODE (XEXP (addr, 1)) == CONST_INT)
2174 addr = XEXP (addr, 0);
2181 if (SYMBOL_REF_DECL (addr)
2182 && decl_readonly_section (SYMBOL_REF_DECL (addr), 0))
2192 /* Given a simple IF-THEN or IF-THEN-ELSE block, attempt to convert it
2193 without using conditional execution. Return TRUE if we were
2194 successful at converting the block. */
2197 noce_process_if_block (struct ce_if_block * ce_info)
2199 basic_block test_bb = ce_info->test_bb; /* test block */
2200 basic_block then_bb = ce_info->then_bb; /* THEN */
2201 basic_block else_bb = ce_info->else_bb; /* ELSE or NULL */
2202 basic_block join_bb;
2203 struct noce_if_info if_info;
2206 rtx orig_x, x, a, b;
2209 /* We're looking for patterns of the form
2211 (1) if (...) x = a; else x = b;
2212 (2) x = b; if (...) x = a;
2213 (3) if (...) x = a; // as if with an initial x = x.
2215 The later patterns require jumps to be more expensive.
2217 ??? For future expansion, look for multiple X in such patterns. */
2219 if (!noce_init_if_info (ce_info, &if_info))
2222 cond = if_info.cond;
2223 jump = if_info.jump;
2225 /* Look for one of the potential sets. */
2226 insn_a = first_active_insn (then_bb);
2228 || insn_a != last_active_insn (then_bb, FALSE)
2229 || (set_a = single_set (insn_a)) == NULL_RTX)
2232 x = SET_DEST (set_a);
2233 a = SET_SRC (set_a);
2235 /* Look for the other potential set. Make sure we've got equivalent
2237 /* ??? This is overconservative. Storing to two different mems is
2238 as easy as conditionally computing the address. Storing to a
2239 single mem merely requires a scratch memory to use as one of the
2240 destination addresses; often the memory immediately below the
2241 stack pointer is available for this. */
2245 insn_b = first_active_insn (else_bb);
2247 || insn_b != last_active_insn (else_bb, FALSE)
2248 || (set_b = single_set (insn_b)) == NULL_RTX
2249 || ! rtx_equal_p (x, SET_DEST (set_b)))
2254 insn_b = prev_nonnote_insn (if_info.cond_earliest);
2255 /* We're going to be moving the evaluation of B down from above
2256 COND_EARLIEST to JUMP. Make sure the relevant data is still
2259 || !NONJUMP_INSN_P (insn_b)
2260 || (set_b = single_set (insn_b)) == NULL_RTX
2261 || ! rtx_equal_p (x, SET_DEST (set_b))
2262 || reg_overlap_mentioned_p (x, SET_SRC (set_b))
2263 || modified_between_p (SET_SRC (set_b),
2264 PREV_INSN (if_info.cond_earliest), jump)
2265 /* Likewise with X. In particular this can happen when
2266 noce_get_condition looks farther back in the instruction
2267 stream than one might expect. */
2268 || reg_overlap_mentioned_p (x, cond)
2269 || reg_overlap_mentioned_p (x, a)
2270 || modified_between_p (x, PREV_INSN (if_info.cond_earliest), jump))
2271 insn_b = set_b = NULL_RTX;
2274 /* If x has side effects then only the if-then-else form is safe to
2275 convert. But even in that case we would need to restore any notes
2276 (such as REG_INC) at then end. That can be tricky if
2277 noce_emit_move_insn expands to more than one insn, so disable the
2278 optimization entirely for now if there are side effects. */
2279 if (side_effects_p (x))
2282 b = (set_b ? SET_SRC (set_b) : x);
2284 /* Only operate on register destinations, and even then avoid extending
2285 the lifetime of hard registers on small register class machines. */
2288 || (SMALL_REGISTER_CLASSES
2289 && REGNO (x) < FIRST_PSEUDO_REGISTER))
2291 if (no_new_pseudos || GET_MODE (x) == BLKmode)
2294 if (GET_MODE (x) == ZERO_EXTRACT
2295 && (GET_CODE (XEXP (x, 1)) != CONST_INT
2296 || GET_CODE (XEXP (x, 2)) != CONST_INT))
2299 x = gen_reg_rtx (GET_MODE (GET_CODE (x) == STRICT_LOW_PART
2300 ? XEXP (x, 0) : x));
2303 /* Don't operate on sources that may trap or are volatile. */
2304 if (! noce_operand_ok (a) || ! noce_operand_ok (b))
2307 /* Set up the info block for our subroutines. */
2308 if_info.insn_a = insn_a;
2309 if_info.insn_b = insn_b;
2314 /* Try optimizations in some approximation of a useful order. */
2315 /* ??? Should first look to see if X is live incoming at all. If it
2316 isn't, we don't need anything but an unconditional set. */
2318 /* Look and see if A and B are really the same. Avoid creating silly
2319 cmove constructs that no one will fix up later. */
2320 if (rtx_equal_p (a, b))
2322 /* If we have an INSN_B, we don't have to create any new rtl. Just
2323 move the instruction that we already have. If we don't have an
2324 INSN_B, that means that A == X, and we've got a noop move. In
2325 that case don't do anything and let the code below delete INSN_A. */
2326 if (insn_b && else_bb)
2330 if (else_bb && insn_b == BB_END (else_bb))
2331 BB_END (else_bb) = PREV_INSN (insn_b);
2332 reorder_insns (insn_b, insn_b, PREV_INSN (jump));
2334 /* If there was a REG_EQUAL note, delete it since it may have been
2335 true due to this insn being after a jump. */
2336 if ((note = find_reg_note (insn_b, REG_EQUAL, NULL_RTX)) != 0)
2337 remove_note (insn_b, note);
2341 /* If we have "x = b; if (...) x = a;", and x has side-effects, then
2342 x must be executed twice. */
2343 else if (insn_b && side_effects_p (orig_x))
2350 /* Disallow the "if (...) x = a;" form (with an implicit "else x = x;")
2351 for optimizations if writing to x may trap or fault, i.e. it's a memory
2352 other than a static var or a stack slot, is misaligned on strict
2353 aligned machines or is read-only.
2354 If x is a read-only memory, then the program is valid only if we
2355 avoid the store into it. If there are stores on both the THEN and
2356 ELSE arms, then we can go ahead with the conversion; either the
2357 program is broken, or the condition is always false such that the
2358 other memory is selected. */
2359 if (!set_b && MEM_P (orig_x) && noce_mem_write_may_trap_or_fault_p (orig_x))
2362 if (noce_try_move (&if_info))
2364 if (noce_try_store_flag (&if_info))
2366 if (noce_try_bitop (&if_info))
2368 if (noce_try_minmax (&if_info))
2370 if (noce_try_abs (&if_info))
2372 if (HAVE_conditional_move
2373 && noce_try_cmove (&if_info))
2375 if (! HAVE_conditional_execution)
2377 if (noce_try_store_flag_constants (&if_info))
2379 if (noce_try_addcc (&if_info))
2381 if (noce_try_store_flag_mask (&if_info))
2383 if (HAVE_conditional_move
2384 && noce_try_cmove_arith (&if_info))
2386 if (noce_try_sign_mask (&if_info))
2394 /* If we used a temporary, fix it up now. */
2400 noce_emit_move_insn (orig_x, x);
2402 set_used_flags (orig_x);
2403 unshare_all_rtl_in_chain (seq);
2406 emit_insn_before_setloc (seq, BB_END (test_bb), INSN_LOCATOR (insn_a));
2409 /* The original THEN and ELSE blocks may now be removed. The test block
2410 must now jump to the join block. If the test block and the join block
2411 can be merged, do so. */
2413 join_bb = single_succ (then_bb);
2416 delete_basic_block (else_bb);
2420 remove_edge (find_edge (test_bb, join_bb));
2422 remove_edge (find_edge (then_bb, join_bb));
2423 redirect_edge_and_branch_force (single_succ_edge (test_bb), join_bb);
2424 delete_basic_block (then_bb);
2427 if (can_merge_blocks_p (test_bb, join_bb))
2429 merge_blocks (test_bb, join_bb);
2433 num_updated_if_blocks++;
2437 /* Check whether a block is suitable for conditional move conversion.
2438 Every insn must be a simple set of a register to a constant or a
2439 register. For each assignment, store the value in the array VALS,
2440 indexed by register number, then store the register number in
2441 REGS. COND is the condition we will test. */
2444 check_cond_move_block (basic_block bb, rtx *vals, VEC (int, heap) *regs, rtx cond)
2448 /* We can only handle simple jumps at the end of the basic block.
2449 It is almost impossible to update the CFG otherwise. */
2451 if (JUMP_P (insn) && !onlyjump_p (insn))
2454 FOR_BB_INSNS (bb, insn)
2458 if (!INSN_P (insn) || JUMP_P (insn))
2460 set = single_set (insn);
2464 dest = SET_DEST (set);
2465 src = SET_SRC (set);
2467 || (SMALL_REGISTER_CLASSES && HARD_REGISTER_P (dest)))
2470 if (!CONSTANT_P (src) && !register_operand (src, VOIDmode))
2473 if (side_effects_p (src) || side_effects_p (dest))
2476 if (may_trap_p (src) || may_trap_p (dest))
2479 /* Don't try to handle this if the source register was
2480 modified earlier in the block. */
2482 && vals[REGNO (src)] != NULL)
2483 || (GET_CODE (src) == SUBREG && REG_P (SUBREG_REG (src))
2484 && vals[REGNO (SUBREG_REG (src))] != NULL))
2487 /* Don't try to handle this if the destination register was
2488 modified earlier in the block. */
2489 if (vals[REGNO (dest)] != NULL)
2492 /* Don't try to handle this if the condition uses the
2493 destination register. */
2494 if (reg_overlap_mentioned_p (dest, cond))
2497 /* Don't try to handle this if the source register is modified
2498 later in the block. */
2499 if (!CONSTANT_P (src)
2500 && modified_between_p (src, insn, NEXT_INSN (BB_END (bb))))
2503 vals[REGNO (dest)] = src;
2505 VEC_safe_push (int, heap, regs, REGNO (dest));
2511 /* Given a basic block BB suitable for conditional move conversion,
2512 a condition COND, and arrays THEN_VALS and ELSE_VALS containing the
2513 register values depending on COND, emit the insns in the block as
2514 conditional moves. If ELSE_BLOCK is true, THEN_BB was already
2515 processed. The caller has started a sequence for the conversion.
2516 Return true if successful, false if something goes wrong. */
2519 cond_move_convert_if_block (struct noce_if_info *if_infop,
2520 basic_block bb, rtx cond,
2521 rtx *then_vals, rtx *else_vals,
2525 rtx insn, cond_arg0, cond_arg1;
2527 code = GET_CODE (cond);
2528 cond_arg0 = XEXP (cond, 0);
2529 cond_arg1 = XEXP (cond, 1);
2531 FOR_BB_INSNS (bb, insn)
2533 rtx set, target, dest, t, e;
2536 if (!INSN_P (insn) || JUMP_P (insn))
2538 set = single_set (insn);
2539 gcc_assert (set && REG_P (SET_DEST (set)));
2541 dest = SET_DEST (set);
2542 regno = REGNO (dest);
2544 t = then_vals[regno];
2545 e = else_vals[regno];
2549 /* If this register was set in the then block, we already
2550 handled this case there. */
2563 target = noce_emit_cmove (if_infop, dest, code, cond_arg0, cond_arg1,
2569 noce_emit_move_insn (dest, target);
2575 /* Given a simple IF-THEN or IF-THEN-ELSE block, attempt to convert it
2576 using only conditional moves. Return TRUE if we were successful at
2577 converting the block. */
2580 cond_move_process_if_block (struct ce_if_block *ce_info)
2582 basic_block test_bb = ce_info->test_bb;
2583 basic_block then_bb = ce_info->then_bb;
2584 basic_block else_bb = ce_info->else_bb;
2585 basic_block join_bb;
2586 struct noce_if_info if_info;
2587 rtx jump, cond, seq, loc_insn;
2588 int max_reg, size, c, reg;
2591 VEC (int, heap) *then_regs = NULL;
2592 VEC (int, heap) *else_regs = NULL;
2595 if (!HAVE_conditional_move || no_new_pseudos)
2598 memset (&if_info, 0, sizeof if_info);
2600 if (!noce_init_if_info (ce_info, &if_info))
2603 cond = if_info.cond;
2604 jump = if_info.jump;
2606 /* Build a mapping for each block to the value used for each
2608 max_reg = max_reg_num ();
2609 size = (max_reg + 1) * sizeof (rtx);
2610 then_vals = (rtx *) alloca (size);
2611 else_vals = (rtx *) alloca (size);
2612 memset (then_vals, 0, size);
2613 memset (else_vals, 0, size);
2615 /* Make sure the blocks are suitable. */
2616 if (!check_cond_move_block (then_bb, then_vals, then_regs, cond)
2617 || (else_bb && !check_cond_move_block (else_bb, else_vals, else_regs, cond)))
2620 /* Make sure the blocks can be used together. If the same register
2621 is set in both blocks, and is not set to a constant in both
2622 cases, then both blocks must set it to the same register. We
2623 have already verified that if it is set to a register, that the
2624 source register does not change after the assignment. Also count
2625 the number of registers set in only one of the blocks. */
2627 for (i = 0; VEC_iterate (int, then_regs, i, reg); i++)
2629 if (!then_vals[reg] && !else_vals[reg])
2632 if (!else_vals[reg])
2636 if (!CONSTANT_P (then_vals[reg])
2637 && !CONSTANT_P (else_vals[reg])
2638 && !rtx_equal_p (then_vals[reg], else_vals[reg]))
2643 /* Finish off c for MAX_CONDITIONAL_EXECUTE. */
2644 for (i = 0; VEC_iterate (int, else_regs, i, reg); ++i)
2645 if (!then_vals[reg])
2648 /* Make sure it is reasonable to convert this block. What matters
2649 is the number of assignments currently made in only one of the
2650 branches, since if we convert we are going to always execute
2652 if (c > MAX_CONDITIONAL_EXECUTE)
2655 /* Try to emit the conditional moves. First do the then block,
2656 then do anything left in the else blocks. */
2658 if (!cond_move_convert_if_block (&if_info, then_bb, cond,
2659 then_vals, else_vals, false)
2661 && !cond_move_convert_if_block (&if_info, else_bb, cond,
2662 then_vals, else_vals, true)))
2667 seq = end_ifcvt_sequence (&if_info);
2671 loc_insn = first_active_insn (then_bb);
2674 loc_insn = first_active_insn (else_bb);
2675 gcc_assert (loc_insn);
2677 emit_insn_before_setloc (seq, jump, INSN_LOCATOR (loc_insn));
2679 join_bb = single_succ (then_bb);
2682 delete_basic_block (else_bb);
2686 remove_edge (find_edge (test_bb, join_bb));
2688 remove_edge (find_edge (then_bb, join_bb));
2689 redirect_edge_and_branch_force (single_succ_edge (test_bb), join_bb);
2690 delete_basic_block (then_bb);
2693 if (can_merge_blocks_p (test_bb, join_bb))
2695 merge_blocks (test_bb, join_bb);
2699 num_updated_if_blocks++;
2701 VEC_free (int, heap, then_regs);
2702 VEC_free (int, heap, else_regs);
2708 /* Attempt to convert an IF-THEN or IF-THEN-ELSE block into
2709 straight line code. Return true if successful. */
2712 process_if_block (struct ce_if_block * ce_info)
2714 /* Only perform the noce transformations before register allocation.
2715 They could be made to run later, but this would require a lot of
2716 work, and it doesn't seem to be worth it. */
2717 if (! reload_completed)
2719 if (noce_process_if_block (ce_info))
2722 if (HAVE_conditional_move
2723 && cond_move_process_if_block (ce_info))
2727 if (HAVE_conditional_execution && reload_completed)
2729 /* If we have && and || tests, try to first handle combining the && and
2730 || tests into the conditional code, and if that fails, go back and
2731 handle it without the && and ||, which at present handles the && case
2732 if there was no ELSE block. */
2733 if (cond_exec_process_if_block (ce_info, TRUE))
2736 if (ce_info->num_multiple_test_blocks)
2740 if (cond_exec_process_if_block (ce_info, FALSE))
2748 /* Merge the blocks and mark for local life update. */
2751 merge_if_block (struct ce_if_block * ce_info)
2753 basic_block test_bb = ce_info->test_bb; /* last test block */
2754 basic_block then_bb = ce_info->then_bb; /* THEN */
2755 basic_block else_bb = ce_info->else_bb; /* ELSE or NULL */
2756 basic_block join_bb = ce_info->join_bb; /* join block */
2757 basic_block combo_bb;
2759 /* All block merging is done into the lower block numbers. */
2763 /* Merge any basic blocks to handle && and || subtests. Each of
2764 the blocks are on the fallthru path from the predecessor block. */
2765 if (ce_info->num_multiple_test_blocks > 0)
2767 basic_block bb = test_bb;
2768 basic_block last_test_bb = ce_info->last_test_bb;
2769 basic_block fallthru = block_fallthru (bb);
2774 fallthru = block_fallthru (bb);
2775 merge_blocks (combo_bb, bb);
2778 while (bb != last_test_bb);
2781 /* Merge TEST block into THEN block. Normally the THEN block won't have a
2782 label, but it might if there were || tests. That label's count should be
2783 zero, and it normally should be removed. */
2787 merge_blocks (combo_bb, then_bb);
2791 /* The ELSE block, if it existed, had a label. That label count
2792 will almost always be zero, but odd things can happen when labels
2793 get their addresses taken. */
2796 merge_blocks (combo_bb, else_bb);
2800 /* If there was no join block reported, that means it was not adjacent
2801 to the others, and so we cannot merge them. */
2805 rtx last = BB_END (combo_bb);
2807 /* The outgoing edge for the current COMBO block should already
2808 be correct. Verify this. */
2809 if (EDGE_COUNT (combo_bb->succs) == 0)
2810 gcc_assert (find_reg_note (last, REG_NORETURN, NULL)
2811 || (NONJUMP_INSN_P (last)
2812 && GET_CODE (PATTERN (last)) == TRAP_IF
2813 && (TRAP_CONDITION (PATTERN (last))
2814 == const_true_rtx)));
2817 /* There should still be something at the end of the THEN or ELSE
2818 blocks taking us to our final destination. */
2819 gcc_assert (JUMP_P (last)
2820 || (EDGE_SUCC (combo_bb, 0)->dest == EXIT_BLOCK_PTR
2822 && SIBLING_CALL_P (last))
2823 || ((EDGE_SUCC (combo_bb, 0)->flags & EDGE_EH)
2824 && can_throw_internal (last)));
2827 /* The JOIN block may have had quite a number of other predecessors too.
2828 Since we've already merged the TEST, THEN and ELSE blocks, we should
2829 have only one remaining edge from our if-then-else diamond. If there
2830 is more than one remaining edge, it must come from elsewhere. There
2831 may be zero incoming edges if the THEN block didn't actually join
2832 back up (as with a call to a non-return function). */
2833 else if (EDGE_COUNT (join_bb->preds) < 2
2834 && join_bb != EXIT_BLOCK_PTR)
2836 /* We can merge the JOIN. */
2837 merge_blocks (combo_bb, join_bb);
2842 /* We cannot merge the JOIN. */
2844 /* The outgoing edge for the current COMBO block should already
2845 be correct. Verify this. */
2846 gcc_assert (single_succ_p (combo_bb)
2847 && single_succ (combo_bb) == join_bb);
2849 /* Remove the jump and cruft from the end of the COMBO block. */
2850 if (join_bb != EXIT_BLOCK_PTR)
2851 tidy_fallthru_edge (single_succ_edge (combo_bb));
2854 num_updated_if_blocks++;
2857 /* Find a block ending in a simple IF condition and try to transform it
2858 in some way. When converting a multi-block condition, put the new code
2859 in the first such block and delete the rest. Return a pointer to this
2860 first block if some transformation was done. Return NULL otherwise. */
2863 find_if_header (basic_block test_bb, int pass)
2865 ce_if_block_t ce_info;
2869 /* The kind of block we're looking for has exactly two successors. */
2870 if (EDGE_COUNT (test_bb->succs) != 2)
2873 then_edge = EDGE_SUCC (test_bb, 0);
2874 else_edge = EDGE_SUCC (test_bb, 1);
2876 /* Neither edge should be abnormal. */
2877 if ((then_edge->flags & EDGE_COMPLEX)
2878 || (else_edge->flags & EDGE_COMPLEX))
2881 /* Nor exit the loop. */
2882 if ((then_edge->flags & EDGE_LOOP_EXIT)
2883 || (else_edge->flags & EDGE_LOOP_EXIT))
2886 /* The THEN edge is canonically the one that falls through. */
2887 if (then_edge->flags & EDGE_FALLTHRU)
2889 else if (else_edge->flags & EDGE_FALLTHRU)
2892 else_edge = then_edge;
2896 /* Otherwise this must be a multiway branch of some sort. */
2899 memset (&ce_info, '\0', sizeof (ce_info));
2900 ce_info.test_bb = test_bb;
2901 ce_info.then_bb = then_edge->dest;
2902 ce_info.else_bb = else_edge->dest;
2903 ce_info.pass = pass;
2905 #ifdef IFCVT_INIT_EXTRA_FIELDS
2906 IFCVT_INIT_EXTRA_FIELDS (&ce_info);
2909 if (find_if_block (&ce_info))
2912 if (HAVE_trap && HAVE_conditional_trap
2913 && find_cond_trap (test_bb, then_edge, else_edge))
2916 if (dom_computed[CDI_POST_DOMINATORS] >= DOM_NO_FAST_QUERY
2917 && (! HAVE_conditional_execution || reload_completed))
2919 if (find_if_case_1 (test_bb, then_edge, else_edge))
2921 if (find_if_case_2 (test_bb, then_edge, else_edge))
2929 fprintf (dump_file, "Conversion succeeded on pass %d.\n", pass);
2930 return ce_info.test_bb;
2933 /* Return true if a block has two edges, one of which falls through to the next
2934 block, and the other jumps to a specific block, so that we can tell if the
2935 block is part of an && test or an || test. Returns either -1 or the number
2936 of non-note, non-jump, non-USE/CLOBBER insns in the block. */
2939 block_jumps_and_fallthru_p (basic_block cur_bb, basic_block target_bb)
2942 int fallthru_p = FALSE;
2949 if (!cur_bb || !target_bb)
2952 /* If no edges, obviously it doesn't jump or fallthru. */
2953 if (EDGE_COUNT (cur_bb->succs) == 0)
2956 FOR_EACH_EDGE (cur_edge, ei, cur_bb->succs)
2958 if (cur_edge->flags & EDGE_COMPLEX)
2959 /* Anything complex isn't what we want. */
2962 else if (cur_edge->flags & EDGE_FALLTHRU)
2965 else if (cur_edge->dest == target_bb)
2972 if ((jump_p & fallthru_p) == 0)
2975 /* Don't allow calls in the block, since this is used to group && and ||
2976 together for conditional execution support. ??? we should support
2977 conditional execution support across calls for IA-64 some day, but
2978 for now it makes the code simpler. */
2979 end = BB_END (cur_bb);
2980 insn = BB_HEAD (cur_bb);
2982 while (insn != NULL_RTX)
2989 && GET_CODE (PATTERN (insn)) != USE
2990 && GET_CODE (PATTERN (insn)) != CLOBBER)
2996 insn = NEXT_INSN (insn);
3002 /* Determine if a given basic block heads a simple IF-THEN or IF-THEN-ELSE
3003 block. If so, we'll try to convert the insns to not require the branch.
3004 Return TRUE if we were successful at converting the block. */
3007 find_if_block (struct ce_if_block * ce_info)
3009 basic_block test_bb = ce_info->test_bb;
3010 basic_block then_bb = ce_info->then_bb;
3011 basic_block else_bb = ce_info->else_bb;
3012 basic_block join_bb = NULL_BLOCK;
3017 ce_info->last_test_bb = test_bb;
3019 /* Discover if any fall through predecessors of the current test basic block
3020 were && tests (which jump to the else block) or || tests (which jump to
3022 if (HAVE_conditional_execution && reload_completed
3023 && single_pred_p (test_bb)
3024 && single_pred_edge (test_bb)->flags == EDGE_FALLTHRU)
3026 basic_block bb = single_pred (test_bb);
3027 basic_block target_bb;
3028 int max_insns = MAX_CONDITIONAL_EXECUTE;
3031 /* Determine if the preceding block is an && or || block. */
3032 if ((n_insns = block_jumps_and_fallthru_p (bb, else_bb)) >= 0)
3034 ce_info->and_and_p = TRUE;
3035 target_bb = else_bb;
3037 else if ((n_insns = block_jumps_and_fallthru_p (bb, then_bb)) >= 0)
3039 ce_info->and_and_p = FALSE;
3040 target_bb = then_bb;
3043 target_bb = NULL_BLOCK;
3045 if (target_bb && n_insns <= max_insns)
3047 int total_insns = 0;
3050 ce_info->last_test_bb = test_bb;
3052 /* Found at least one && or || block, look for more. */
3055 ce_info->test_bb = test_bb = bb;
3056 total_insns += n_insns;
3059 if (!single_pred_p (bb))
3062 bb = single_pred (bb);
3063 n_insns = block_jumps_and_fallthru_p (bb, target_bb);
3065 while (n_insns >= 0 && (total_insns + n_insns) <= max_insns);
3067 ce_info->num_multiple_test_blocks = blocks;
3068 ce_info->num_multiple_test_insns = total_insns;
3070 if (ce_info->and_and_p)
3071 ce_info->num_and_and_blocks = blocks;
3073 ce_info->num_or_or_blocks = blocks;
3077 /* The THEN block of an IF-THEN combo must have exactly one predecessor,
3078 other than any || blocks which jump to the THEN block. */
3079 if ((EDGE_COUNT (then_bb->preds) - ce_info->num_or_or_blocks) != 1)
3082 /* The edges of the THEN and ELSE blocks cannot have complex edges. */
3083 FOR_EACH_EDGE (cur_edge, ei, then_bb->preds)
3085 if (cur_edge->flags & EDGE_COMPLEX)
3089 FOR_EACH_EDGE (cur_edge, ei, else_bb->preds)
3091 if (cur_edge->flags & EDGE_COMPLEX)
3095 /* The THEN block of an IF-THEN combo must have zero or one successors. */
3096 if (EDGE_COUNT (then_bb->succs) > 0
3097 && (!single_succ_p (then_bb)
3098 || (single_succ_edge (then_bb)->flags & EDGE_COMPLEX)
3099 || (flow2_completed && tablejump_p (BB_END (then_bb), NULL, NULL))))
3102 /* If the THEN block has no successors, conditional execution can still
3103 make a conditional call. Don't do this unless the ELSE block has
3104 only one incoming edge -- the CFG manipulation is too ugly otherwise.
3105 Check for the last insn of the THEN block being an indirect jump, which
3106 is listed as not having any successors, but confuses the rest of the CE
3107 code processing. ??? we should fix this in the future. */
3108 if (EDGE_COUNT (then_bb->succs) == 0)
3110 if (single_pred_p (else_bb))
3112 rtx last_insn = BB_END (then_bb);
3115 && NOTE_P (last_insn)
3116 && last_insn != BB_HEAD (then_bb))
3117 last_insn = PREV_INSN (last_insn);
3120 && JUMP_P (last_insn)
3121 && ! simplejump_p (last_insn))
3125 else_bb = NULL_BLOCK;
3131 /* If the THEN block's successor is the other edge out of the TEST block,
3132 then we have an IF-THEN combo without an ELSE. */
3133 else if (single_succ (then_bb) == else_bb)
3136 else_bb = NULL_BLOCK;
3139 /* If the THEN and ELSE block meet in a subsequent block, and the ELSE
3140 has exactly one predecessor and one successor, and the outgoing edge
3141 is not complex, then we have an IF-THEN-ELSE combo. */
3142 else if (single_succ_p (else_bb)
3143 && single_succ (then_bb) == single_succ (else_bb)
3144 && single_pred_p (else_bb)
3145 && ! (single_succ_edge (else_bb)->flags & EDGE_COMPLEX)
3146 && ! (flow2_completed && tablejump_p (BB_END (else_bb), NULL, NULL)))
3147 join_bb = single_succ (else_bb);
3149 /* Otherwise it is not an IF-THEN or IF-THEN-ELSE combination. */
3153 num_possible_if_blocks++;
3158 "\nIF-THEN%s block found, pass %d, start block %d "
3159 "[insn %d], then %d [%d]",
3160 (else_bb) ? "-ELSE" : "",
3163 BB_HEAD (test_bb) ? (int)INSN_UID (BB_HEAD (test_bb)) : -1,
3165 BB_HEAD (then_bb) ? (int)INSN_UID (BB_HEAD (then_bb)) : -1);
3168 fprintf (dump_file, ", else %d [%d]",
3170 BB_HEAD (else_bb) ? (int)INSN_UID (BB_HEAD (else_bb)) : -1);
3172 fprintf (dump_file, ", join %d [%d]",
3174 BB_HEAD (join_bb) ? (int)INSN_UID (BB_HEAD (join_bb)) : -1);
3176 if (ce_info->num_multiple_test_blocks > 0)
3177 fprintf (dump_file, ", %d %s block%s last test %d [%d]",
3178 ce_info->num_multiple_test_blocks,
3179 (ce_info->and_and_p) ? "&&" : "||",
3180 (ce_info->num_multiple_test_blocks == 1) ? "" : "s",
3181 ce_info->last_test_bb->index,
3182 ((BB_HEAD (ce_info->last_test_bb))
3183 ? (int)INSN_UID (BB_HEAD (ce_info->last_test_bb))
3186 fputc ('\n', dump_file);
3189 /* Make sure IF, THEN, and ELSE, blocks are adjacent. Actually, we get the
3190 first condition for free, since we've already asserted that there's a
3191 fallthru edge from IF to THEN. Likewise for the && and || blocks, since
3192 we checked the FALLTHRU flag, those are already adjacent to the last IF
3194 /* ??? As an enhancement, move the ELSE block. Have to deal with
3195 BLOCK notes, if by no other means than backing out the merge if they
3196 exist. Sticky enough I don't want to think about it now. */
3198 if (else_bb && (next = next->next_bb) != else_bb)
3200 if ((next = next->next_bb) != join_bb && join_bb != EXIT_BLOCK_PTR)
3208 /* Do the real work. */
3209 ce_info->else_bb = else_bb;
3210 ce_info->join_bb = join_bb;
3212 return process_if_block (ce_info);
3215 /* Convert a branch over a trap, or a branch
3216 to a trap, into a conditional trap. */
3219 find_cond_trap (basic_block test_bb, edge then_edge, edge else_edge)
3221 basic_block then_bb = then_edge->dest;
3222 basic_block else_bb = else_edge->dest;
3223 basic_block other_bb, trap_bb;
3224 rtx trap, jump, cond, cond_earliest, seq;
3227 /* Locate the block with the trap instruction. */
3228 /* ??? While we look for no successors, we really ought to allow
3229 EH successors. Need to fix merge_if_block for that to work. */
3230 if ((trap = block_has_only_trap (then_bb)) != NULL)
3231 trap_bb = then_bb, other_bb = else_bb;
3232 else if ((trap = block_has_only_trap (else_bb)) != NULL)
3233 trap_bb = else_bb, other_bb = then_bb;
3239 fprintf (dump_file, "\nTRAP-IF block found, start %d, trap %d\n",
3240 test_bb->index, trap_bb->index);
3243 /* If this is not a standard conditional jump, we can't parse it. */
3244 jump = BB_END (test_bb);
3245 cond = noce_get_condition (jump, &cond_earliest);
3249 /* If the conditional jump is more than just a conditional jump, then
3250 we can not do if-conversion on this block. */
3251 if (! onlyjump_p (jump))
3254 /* We must be comparing objects whose modes imply the size. */
3255 if (GET_MODE (XEXP (cond, 0)) == BLKmode)
3258 /* Reverse the comparison code, if necessary. */
3259 code = GET_CODE (cond);
3260 if (then_bb == trap_bb)
3262 code = reversed_comparison_code (cond, jump);
3263 if (code == UNKNOWN)
3267 /* Attempt to generate the conditional trap. */
3268 seq = gen_cond_trap (code, XEXP (cond, 0),
3270 TRAP_CODE (PATTERN (trap)));
3274 /* Emit the new insns before cond_earliest. */
3275 emit_insn_before_setloc (seq, cond_earliest, INSN_LOCATOR (trap));
3277 /* Delete the trap block if possible. */
3278 remove_edge (trap_bb == then_bb ? then_edge : else_edge);
3279 if (EDGE_COUNT (trap_bb->preds) == 0)
3281 delete_basic_block (trap_bb);
3285 /* Wire together the blocks again. */
3286 if (current_ir_type () == IR_RTL_CFGLAYOUT)
3287 single_succ_edge (test_bb)->flags |= EDGE_FALLTHRU;
3292 lab = JUMP_LABEL (jump);
3293 newjump = emit_jump_insn_after (gen_jump (lab), jump);
3294 LABEL_NUSES (lab) += 1;
3295 JUMP_LABEL (newjump) = lab;
3296 emit_barrier_after (newjump);
3300 if (can_merge_blocks_p (test_bb, other_bb))
3302 merge_blocks (test_bb, other_bb);
3306 num_updated_if_blocks++;
3310 /* Subroutine of find_cond_trap: if BB contains only a trap insn,
3314 block_has_only_trap (basic_block bb)
3318 /* We're not the exit block. */
3319 if (bb == EXIT_BLOCK_PTR)
3322 /* The block must have no successors. */
3323 if (EDGE_COUNT (bb->succs) > 0)
3326 /* The only instruction in the THEN block must be the trap. */
3327 trap = first_active_insn (bb);
3328 if (! (trap == BB_END (bb)
3329 && GET_CODE (PATTERN (trap)) == TRAP_IF
3330 && TRAP_CONDITION (PATTERN (trap)) == const_true_rtx))
3336 /* Look for IF-THEN-ELSE cases in which one of THEN or ELSE is
3337 transformable, but not necessarily the other. There need be no
3340 Return TRUE if we were successful at converting the block.
3342 Cases we'd like to look at:
3345 if (test) goto over; // x not live
3353 if (! test) goto label;
3356 if (test) goto E; // x not live
3370 (3) // This one's really only interesting for targets that can do
3371 // multiway branching, e.g. IA-64 BBB bundles. For other targets
3372 // it results in multiple branches on a cache line, which often
3373 // does not sit well with predictors.
3375 if (test1) goto E; // predicted not taken
3391 (A) Don't do (2) if the branch is predicted against the block we're
3392 eliminating. Do it anyway if we can eliminate a branch; this requires
3393 that the sole successor of the eliminated block postdominate the other
3396 (B) With CE, on (3) we can steal from both sides of the if, creating
3405 Again, this is most useful if J postdominates.
3407 (C) CE substitutes for helpful life information.
3409 (D) These heuristics need a lot of work. */
3411 /* Tests for case 1 above. */
3414 find_if_case_1 (basic_block test_bb, edge then_edge, edge else_edge)
3416 basic_block then_bb = then_edge->dest;
3417 basic_block else_bb = else_edge->dest, new_bb;
3420 /* If we are partitioning hot/cold basic blocks, we don't want to
3421 mess up unconditional or indirect jumps that cross between hot
3424 Basic block partitioning may result in some jumps that appear to
3425 be optimizable (or blocks that appear to be mergeable), but which really
3426 must be left untouched (they are required to make it safely across
3427 partition boundaries). See the comments at the top of
3428 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
3430 if ((BB_END (then_bb)
3431 && find_reg_note (BB_END (then_bb), REG_CROSSING_JUMP, NULL_RTX))
3432 || (BB_END (test_bb)
3433 && find_reg_note (BB_END (test_bb), REG_CROSSING_JUMP, NULL_RTX))
3434 || (BB_END (else_bb)
3435 && find_reg_note (BB_END (else_bb), REG_CROSSING_JUMP,
3439 /* THEN has one successor. */
3440 if (!single_succ_p (then_bb))
3443 /* THEN does not fall through, but is not strange either. */
3444 if (single_succ_edge (then_bb)->flags & (EDGE_COMPLEX | EDGE_FALLTHRU))
3447 /* THEN has one predecessor. */
3448 if (!single_pred_p (then_bb))
3451 /* THEN must do something. */
3452 if (forwarder_block_p (then_bb))
3455 num_possible_if_blocks++;
3458 "\nIF-CASE-1 found, start %d, then %d\n",
3459 test_bb->index, then_bb->index);
3461 /* THEN is small. */
3462 if (! cheap_bb_rtx_cost_p (then_bb, COSTS_N_INSNS (BRANCH_COST)))
3465 /* Registers set are dead, or are predicable. */
3466 if (! dead_or_predicable (test_bb, then_bb, else_bb,
3467 single_succ (then_bb), 1))
3470 /* Conversion went ok, including moving the insns and fixing up the
3471 jump. Adjust the CFG to match. */
3473 bitmap_ior (test_bb->il.rtl->global_live_at_end,
3474 else_bb->il.rtl->global_live_at_start,
3475 then_bb->il.rtl->global_live_at_end);
3478 /* We can avoid creating a new basic block if then_bb is immediately
3479 followed by else_bb, i.e. deleting then_bb allows test_bb to fall
3482 if (then_bb->next_bb == else_bb
3483 && then_bb->prev_bb == test_bb
3484 && else_bb != EXIT_BLOCK_PTR)
3486 redirect_edge_succ (FALLTHRU_EDGE (test_bb), else_bb);
3490 new_bb = redirect_edge_and_branch_force (FALLTHRU_EDGE (test_bb),
3493 then_bb_index = then_bb->index;
3494 delete_basic_block (then_bb);
3496 /* Make rest of code believe that the newly created block is the THEN_BB
3497 block we removed. */
3500 new_bb->index = then_bb_index;
3501 SET_BASIC_BLOCK (then_bb_index, new_bb);
3502 /* Since the fallthru edge was redirected from test_bb to new_bb,
3503 we need to ensure that new_bb is in the same partition as
3504 test bb (you can not fall through across section boundaries). */
3505 BB_COPY_PARTITION (new_bb, test_bb);
3507 /* We've possibly created jump to next insn, cleanup_cfg will solve that
3511 num_updated_if_blocks++;
3516 /* Test for case 2 above. */
3519 find_if_case_2 (basic_block test_bb, edge then_edge, edge else_edge)
3521 basic_block then_bb = then_edge->dest;
3522 basic_block else_bb = else_edge->dest;
3526 /* If we are partitioning hot/cold basic blocks, we don't want to
3527 mess up unconditional or indirect jumps that cross between hot
3530 Basic block partitioning may result in some jumps that appear to
3531 be optimizable (or blocks that appear to be mergeable), but which really
3532 must be left untouched (they are required to make it safely across
3533 partition boundaries). See the comments at the top of
3534 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
3536 if ((BB_END (then_bb)
3537 && find_reg_note (BB_END (then_bb), REG_CROSSING_JUMP, NULL_RTX))
3538 || (BB_END (test_bb)
3539 && find_reg_note (BB_END (test_bb), REG_CROSSING_JUMP, NULL_RTX))
3540 || (BB_END (else_bb)
3541 && find_reg_note (BB_END (else_bb), REG_CROSSING_JUMP,
3545 /* ELSE has one successor. */
3546 if (!single_succ_p (else_bb))
3549 else_succ = single_succ_edge (else_bb);
3551 /* ELSE outgoing edge is not complex. */
3552 if (else_succ->flags & EDGE_COMPLEX)
3555 /* ELSE has one predecessor. */
3556 if (!single_pred_p (else_bb))
3559 /* THEN is not EXIT. */
3560 if (then_bb->index < NUM_FIXED_BLOCKS)
3563 /* ELSE is predicted or SUCC(ELSE) postdominates THEN. */
3564 note = find_reg_note (BB_END (test_bb), REG_BR_PROB, NULL_RTX);
3565 if (note && INTVAL (XEXP (note, 0)) >= REG_BR_PROB_BASE / 2)
3567 else if (else_succ->dest->index < NUM_FIXED_BLOCKS
3568 || dominated_by_p (CDI_POST_DOMINATORS, then_bb,
3574 num_possible_if_blocks++;
3577 "\nIF-CASE-2 found, start %d, else %d\n",
3578 test_bb->index, else_bb->index);
3580 /* ELSE is small. */
3581 if (! cheap_bb_rtx_cost_p (else_bb, COSTS_N_INSNS (BRANCH_COST)))
3584 /* Registers set are dead, or are predicable. */
3585 if (! dead_or_predicable (test_bb, else_bb, then_bb, else_succ->dest, 0))
3588 /* Conversion went ok, including moving the insns and fixing up the
3589 jump. Adjust the CFG to match. */
3591 bitmap_ior (test_bb->il.rtl->global_live_at_end,
3592 then_bb->il.rtl->global_live_at_start,
3593 else_bb->il.rtl->global_live_at_end);
3595 delete_basic_block (else_bb);
3598 num_updated_if_blocks++;
3600 /* ??? We may now fallthru from one of THEN's successors into a join
3601 block. Rerun cleanup_cfg? Examine things manually? Wait? */
3606 /* A subroutine of dead_or_predicable called through for_each_rtx.
3607 Return 1 if a memory is found. */
3610 find_memory (rtx *px, void *data ATTRIBUTE_UNUSED)
3615 /* Used by the code above to perform the actual rtl transformations.
3616 Return TRUE if successful.
3618 TEST_BB is the block containing the conditional branch. MERGE_BB
3619 is the block containing the code to manipulate. NEW_DEST is the
3620 label TEST_BB should be branching to after the conversion.
3621 REVERSEP is true if the sense of the branch should be reversed. */
3624 dead_or_predicable (basic_block test_bb, basic_block merge_bb,
3625 basic_block other_bb, basic_block new_dest, int reversep)
3627 rtx head, end, jump, earliest = NULL_RTX, old_dest, new_label = NULL_RTX;
3629 jump = BB_END (test_bb);
3631 /* Find the extent of the real code in the merge block. */
3632 head = BB_HEAD (merge_bb);
3633 end = BB_END (merge_bb);
3635 /* If merge_bb ends with a tablejump, predicating/moving insn's
3636 into test_bb and then deleting merge_bb will result in the jumptable
3637 that follows merge_bb being removed along with merge_bb and then we
3638 get an unresolved reference to the jumptable. */
3639 if (tablejump_p (end, NULL, NULL))
3643 head = NEXT_INSN (head);
3648 head = end = NULL_RTX;
3651 head = NEXT_INSN (head);
3658 head = end = NULL_RTX;
3661 end = PREV_INSN (end);
3664 /* Disable handling dead code by conditional execution if the machine needs
3665 to do anything funny with the tests, etc. */
3666 #ifndef IFCVT_MODIFY_TESTS
3667 if (HAVE_conditional_execution)
3669 /* In the conditional execution case, we have things easy. We know
3670 the condition is reversible. We don't have to check life info
3671 because we're going to conditionally execute the code anyway.
3672 All that's left is making sure the insns involved can actually
3677 cond = cond_exec_get_condition (jump);
3681 prob_val = find_reg_note (jump, REG_BR_PROB, NULL_RTX);
3683 prob_val = XEXP (prob_val, 0);
3687 enum rtx_code rev = reversed_comparison_code (cond, jump);
3690 cond = gen_rtx_fmt_ee (rev, GET_MODE (cond), XEXP (cond, 0),
3693 prob_val = GEN_INT (REG_BR_PROB_BASE - INTVAL (prob_val));
3696 if (! cond_exec_process_insns ((ce_if_block_t *)0, head, end, cond,
3705 /* In the non-conditional execution case, we have to verify that there
3706 are no trapping operations, no calls, no references to memory, and
3707 that any registers modified are dead at the branch site. */
3709 rtx insn, cond, prev;
3710 regset merge_set, tmp, test_live, test_set;
3711 struct propagate_block_info *pbi;
3712 unsigned i, fail = 0;
3715 /* Check for no calls or trapping operations. */
3716 for (insn = head; ; insn = NEXT_INSN (insn))
3722 if (may_trap_p (PATTERN (insn)))
3725 /* ??? Even non-trapping memories such as stack frame
3726 references must be avoided. For stores, we collect
3727 no lifetime info; for reads, we'd have to assert
3728 true_dependence false against every store in the
3730 if (for_each_rtx (&PATTERN (insn), find_memory, NULL))
3737 if (! any_condjump_p (jump))
3740 /* Find the extent of the conditional. */
3741 cond = noce_get_condition (jump, &earliest);
3746 MERGE_SET = set of registers set in MERGE_BB
3747 TEST_LIVE = set of registers live at EARLIEST
3748 TEST_SET = set of registers set between EARLIEST and the
3749 end of the block. */
3751 tmp = ALLOC_REG_SET (®_obstack);
3752 merge_set = ALLOC_REG_SET (®_obstack);
3753 test_live = ALLOC_REG_SET (®_obstack);
3754 test_set = ALLOC_REG_SET (®_obstack);
3756 /* ??? bb->local_set is only valid during calculate_global_regs_live,
3757 so we must recompute usage for MERGE_BB. Not so bad, I suppose,
3758 since we've already asserted that MERGE_BB is small. */
3759 /* If we allocated new pseudos (e.g. in the conditional move
3760 expander called from noce_emit_cmove), we must resize the
3762 if (max_regno < max_reg_num ())
3764 max_regno = max_reg_num ();
3765 allocate_reg_info (max_regno, FALSE, FALSE);
3767 propagate_block (merge_bb, tmp, merge_set, merge_set, 0);
3769 /* For small register class machines, don't lengthen lifetimes of
3770 hard registers before reload. */
3771 if (SMALL_REGISTER_CLASSES && ! reload_completed)
3773 EXECUTE_IF_SET_IN_BITMAP (merge_set, 0, i, bi)
3775 if (i < FIRST_PSEUDO_REGISTER
3777 && ! global_regs[i])
3782 /* For TEST, we're interested in a range of insns, not a whole block.
3783 Moreover, we're interested in the insns live from OTHER_BB. */
3785 COPY_REG_SET (test_live, other_bb->il.rtl->global_live_at_start);
3786 pbi = init_propagate_block_info (test_bb, test_live, test_set, test_set,
3789 for (insn = jump; ; insn = prev)
3791 prev = propagate_one_insn (pbi, insn);
3792 if (insn == earliest)
3796 free_propagate_block_info (pbi);
3798 /* We can perform the transformation if
3799 MERGE_SET & (TEST_SET | TEST_LIVE)
3801 TEST_SET & merge_bb->il.rtl->global_live_at_start
3804 if (bitmap_intersect_p (test_set, merge_set)
3805 || bitmap_intersect_p (test_live, merge_set)
3806 || bitmap_intersect_p (test_set,
3807 merge_bb->il.rtl->global_live_at_start))
3811 FREE_REG_SET (merge_set);
3812 FREE_REG_SET (test_live);
3813 FREE_REG_SET (test_set);
3820 /* We don't want to use normal invert_jump or redirect_jump because
3821 we don't want to delete_insn called. Also, we want to do our own
3822 change group management. */
3824 old_dest = JUMP_LABEL (jump);
3825 if (other_bb != new_dest)
3827 new_label = block_label (new_dest);
3829 ? ! invert_jump_1 (jump, new_label)
3830 : ! redirect_jump_1 (jump, new_label))
3834 if (! apply_change_group ())
3837 if (other_bb != new_dest)
3839 redirect_jump_2 (jump, old_dest, new_label, 0, reversep);
3841 redirect_edge_succ (BRANCH_EDGE (test_bb), new_dest);
3844 gcov_type count, probability;
3845 count = BRANCH_EDGE (test_bb)->count;
3846 BRANCH_EDGE (test_bb)->count = FALLTHRU_EDGE (test_bb)->count;
3847 FALLTHRU_EDGE (test_bb)->count = count;
3848 probability = BRANCH_EDGE (test_bb)->probability;
3849 BRANCH_EDGE (test_bb)->probability
3850 = FALLTHRU_EDGE (test_bb)->probability;
3851 FALLTHRU_EDGE (test_bb)->probability = probability;
3852 update_br_prob_note (test_bb);
3856 /* Move the insns out of MERGE_BB to before the branch. */
3861 if (end == BB_END (merge_bb))
3862 BB_END (merge_bb) = PREV_INSN (head);
3864 if (squeeze_notes (&head, &end))
3867 /* PR 21767: When moving insns above a conditional branch, REG_EQUAL
3868 notes might become invalid. */
3874 if (! INSN_P (insn))
3876 note = find_reg_note (insn, REG_EQUAL, NULL_RTX);
3879 set = single_set (insn);
3880 if (!set || !function_invariant_p (SET_SRC (set)))
3881 remove_note (insn, note);
3882 } while (insn != end && (insn = NEXT_INSN (insn)));
3884 reorder_insns (head, end, PREV_INSN (earliest));
3887 /* Remove the jump and edge if we can. */
3888 if (other_bb == new_dest)
3891 remove_edge (BRANCH_EDGE (test_bb));
3892 /* ??? Can't merge blocks here, as then_bb is still in use.
3893 At minimum, the merge will get done just before bb-reorder. */
3903 /* Main entry point for all if-conversion. */
3906 if_convert (int x_life_data_ok)
3911 num_possible_if_blocks = 0;
3912 num_updated_if_blocks = 0;
3913 num_true_changes = 0;
3914 life_data_ok = (x_life_data_ok != 0);
3916 loop_optimizer_init (AVOID_CFG_MODIFICATIONS);
3919 mark_loop_exit_edges ();
3920 loop_optimizer_finalize ();
3922 free_dominance_info (CDI_DOMINATORS);
3924 /* Compute postdominators if we think we'll use them. */
3925 if (HAVE_conditional_execution || life_data_ok)
3926 calculate_dominance_info (CDI_POST_DOMINATORS);
3931 /* Go through each of the basic blocks looking for things to convert. If we
3932 have conditional execution, we make multiple passes to allow us to handle
3933 IF-THEN{-ELSE} blocks within other IF-THEN{-ELSE} blocks. */
3937 cond_exec_changed_p = FALSE;
3940 #ifdef IFCVT_MULTIPLE_DUMPS
3941 if (dump_file && pass > 1)
3942 fprintf (dump_file, "\n\n========== Pass %d ==========\n", pass);
3948 while ((new_bb = find_if_header (bb, pass)))
3952 #ifdef IFCVT_MULTIPLE_DUMPS
3953 if (dump_file && cond_exec_changed_p)
3954 print_rtl_with_bb (dump_file, get_insns ());
3957 while (cond_exec_changed_p);
3959 #ifdef IFCVT_MULTIPLE_DUMPS
3961 fprintf (dump_file, "\n\n========== no more changes\n");
3964 free_dominance_info (CDI_POST_DOMINATORS);
3969 clear_aux_for_blocks ();
3971 /* Rebuild life info for basic blocks that require it. */
3972 if (num_true_changes && life_data_ok)
3974 /* If we allocated new pseudos, we must resize the array for sched1. */
3975 if (max_regno < max_reg_num ())
3977 max_regno = max_reg_num ();
3978 allocate_reg_info (max_regno, FALSE, FALSE);
3980 update_life_info_in_dirty_blocks (UPDATE_LIFE_GLOBAL_RM_NOTES,
3981 PROP_DEATH_NOTES | PROP_SCAN_DEAD_CODE
3982 | PROP_KILL_DEAD_CODE);
3985 /* Write the final stats. */
3986 if (dump_file && num_possible_if_blocks > 0)
3989 "\n%d possible IF blocks searched.\n",
3990 num_possible_if_blocks);
3992 "%d IF blocks converted.\n",
3993 num_updated_if_blocks);
3995 "%d true changes made.\n\n\n",
3999 #ifdef ENABLE_CHECKING
4000 verify_flow_info ();
4005 gate_handle_if_conversion (void)
4007 return (optimize > 0);
4010 /* If-conversion and CFG cleanup. */
4012 rest_of_handle_if_conversion (void)
4014 if (flag_if_conversion)
4017 dump_flow_info (dump_file, dump_flags);
4018 cleanup_cfg (CLEANUP_EXPENSIVE);
4019 reg_scan (get_insns (), max_reg_num ());
4023 timevar_push (TV_JUMP);
4024 cleanup_cfg (CLEANUP_EXPENSIVE);
4025 reg_scan (get_insns (), max_reg_num ());
4026 timevar_pop (TV_JUMP);
4030 struct tree_opt_pass pass_rtl_ifcvt =
4033 gate_handle_if_conversion, /* gate */
4034 rest_of_handle_if_conversion, /* execute */
4037 0, /* static_pass_number */
4038 TV_IFCVT, /* tv_id */
4039 0, /* properties_required */
4040 0, /* properties_provided */
4041 0, /* properties_destroyed */
4042 0, /* todo_flags_start */
4043 TODO_dump_func, /* todo_flags_finish */
4048 gate_handle_if_after_combine (void)
4050 return (optimize > 0 && flag_if_conversion);
4054 /* Rerun if-conversion, as combine may have simplified things enough
4055 to now meet sequence length restrictions. */
4057 rest_of_handle_if_after_combine (void)
4065 struct tree_opt_pass pass_if_after_combine =
4068 gate_handle_if_after_combine, /* gate */
4069 rest_of_handle_if_after_combine, /* execute */
4072 0, /* static_pass_number */
4073 TV_IFCVT, /* tv_id */
4074 0, /* properties_required */
4075 0, /* properties_provided */
4076 0, /* properties_destroyed */
4077 0, /* todo_flags_start */
4079 TODO_ggc_collect, /* todo_flags_finish */
4085 gate_handle_if_after_reload (void)
4087 return (optimize > 0);
4091 rest_of_handle_if_after_reload (void)
4093 /* Last attempt to optimize CFG, as scheduling, peepholing and insn
4094 splitting possibly introduced more crossjumping opportunities. */
4095 cleanup_cfg (CLEANUP_EXPENSIVE
4096 | CLEANUP_UPDATE_LIFE
4097 | (flag_crossjumping ? CLEANUP_CROSSJUMP : 0));
4098 if (flag_if_conversion2)
4104 struct tree_opt_pass pass_if_after_reload =
4107 gate_handle_if_after_reload, /* gate */
4108 rest_of_handle_if_after_reload, /* execute */
4111 0, /* static_pass_number */
4112 TV_IFCVT2, /* tv_id */
4113 0, /* properties_required */
4114 0, /* properties_provided */
4115 0, /* properties_destroyed */
4116 0, /* todo_flags_start */
4118 TODO_ggc_collect, /* todo_flags_finish */