1 /* If-conversion support.
2 Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2010,
4 Free Software Foundation, Inc.
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify it
9 under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
13 GCC is distributed in the hope that it will be useful, but WITHOUT
14 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
15 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
16 License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
24 #include "coretypes.h"
31 #include "insn-config.h"
34 #include "hard-reg-set.h"
35 #include "basic-block.h"
39 #include "diagnostic-core.h"
44 #include "tree-pass.h"
50 #ifndef HAVE_conditional_move
51 #define HAVE_conditional_move 0
63 #ifndef MAX_CONDITIONAL_EXECUTE
64 #define MAX_CONDITIONAL_EXECUTE \
65 (BRANCH_COST (optimize_function_for_speed_p (cfun), false) \
69 #define IFCVT_MULTIPLE_DUMPS 1
71 #define NULL_BLOCK ((basic_block) NULL)
73 /* # of IF-THEN or IF-THEN-ELSE blocks we looked at */
74 static int num_possible_if_blocks
;
76 /* # of IF-THEN or IF-THEN-ELSE blocks were converted to conditional
78 static int num_updated_if_blocks
;
80 /* # of changes made. */
81 static int num_true_changes
;
83 /* Whether conditional execution changes were made. */
84 static int cond_exec_changed_p
;
86 /* Forward references. */
87 static int count_bb_insns (const_basic_block
);
88 static bool cheap_bb_rtx_cost_p (const_basic_block
, int);
89 static rtx
first_active_insn (basic_block
);
90 static rtx
last_active_insn (basic_block
, int);
91 static rtx
find_active_insn_before (basic_block
, rtx
);
92 static rtx
find_active_insn_after (basic_block
, rtx
);
93 static basic_block
block_fallthru (basic_block
);
94 static int cond_exec_process_insns (ce_if_block_t
*, rtx
, rtx
, rtx
, rtx
, int);
95 static rtx
cond_exec_get_condition (rtx
);
96 static rtx
noce_get_condition (rtx
, rtx
*, bool);
97 static int noce_operand_ok (const_rtx
);
98 static void merge_if_block (ce_if_block_t
*);
99 static int find_cond_trap (basic_block
, edge
, edge
);
100 static basic_block
find_if_header (basic_block
, int);
101 static int block_jumps_and_fallthru_p (basic_block
, basic_block
);
102 static int noce_find_if_block (basic_block
, edge
, edge
, int);
103 static int cond_exec_find_if_block (ce_if_block_t
*);
104 static int find_if_case_1 (basic_block
, edge
, edge
);
105 static int find_if_case_2 (basic_block
, edge
, edge
);
106 static int dead_or_predicable (basic_block
, basic_block
, basic_block
,
108 static void noce_emit_move_insn (rtx
, rtx
);
109 static rtx
block_has_only_trap (basic_block
);
111 /* Count the number of non-jump active insns in BB. */
114 count_bb_insns (const_basic_block bb
)
117 rtx insn
= BB_HEAD (bb
);
121 if (CALL_P (insn
) || NONJUMP_INSN_P (insn
))
124 if (insn
== BB_END (bb
))
126 insn
= NEXT_INSN (insn
);
132 /* Determine whether the total insn_rtx_cost on non-jump insns in
133 basic block BB is less than MAX_COST. This function returns
134 false if the cost of any instruction could not be estimated. */
137 cheap_bb_rtx_cost_p (const_basic_block bb
, int max_cost
)
140 rtx insn
= BB_HEAD (bb
);
141 bool speed
= optimize_bb_for_speed_p (bb
);
145 if (NONJUMP_INSN_P (insn
))
147 int cost
= insn_rtx_cost (PATTERN (insn
), speed
);
151 /* If this instruction is the load or set of a "stack" register,
152 such as a floating point register on x87, then the cost of
153 speculatively executing this insn may need to include
154 the additional cost of popping its result off of the
155 register stack. Unfortunately, correctly recognizing and
156 accounting for this additional overhead is tricky, so for
157 now we simply prohibit such speculative execution. */
160 rtx set
= single_set (insn
);
161 if (set
&& STACK_REG_P (SET_DEST (set
)))
167 if (count
>= max_cost
)
170 else if (CALL_P (insn
))
173 if (insn
== BB_END (bb
))
175 insn
= NEXT_INSN (insn
);
181 /* Return the first non-jump active insn in the basic block. */
184 first_active_insn (basic_block bb
)
186 rtx insn
= BB_HEAD (bb
);
190 if (insn
== BB_END (bb
))
192 insn
= NEXT_INSN (insn
);
195 while (NOTE_P (insn
) || DEBUG_INSN_P (insn
))
197 if (insn
== BB_END (bb
))
199 insn
= NEXT_INSN (insn
);
208 /* Return the last non-jump active (non-jump) insn in the basic block. */
211 last_active_insn (basic_block bb
, int skip_use_p
)
213 rtx insn
= BB_END (bb
);
214 rtx head
= BB_HEAD (bb
);
218 || DEBUG_INSN_P (insn
)
220 && NONJUMP_INSN_P (insn
)
221 && GET_CODE (PATTERN (insn
)) == USE
))
225 insn
= PREV_INSN (insn
);
234 /* Return the active insn before INSN inside basic block CURR_BB. */
237 find_active_insn_before (basic_block curr_bb
, rtx insn
)
239 if (!insn
|| insn
== BB_HEAD (curr_bb
))
242 while ((insn
= PREV_INSN (insn
)) != NULL_RTX
)
244 if (NONJUMP_INSN_P (insn
) || JUMP_P (insn
) || CALL_P (insn
))
247 /* No other active insn all the way to the start of the basic block. */
248 if (insn
== BB_HEAD (curr_bb
))
255 /* Return the active insn after INSN inside basic block CURR_BB. */
258 find_active_insn_after (basic_block curr_bb
, rtx insn
)
260 if (!insn
|| insn
== BB_END (curr_bb
))
263 while ((insn
= NEXT_INSN (insn
)) != NULL_RTX
)
265 if (NONJUMP_INSN_P (insn
) || JUMP_P (insn
) || CALL_P (insn
))
268 /* No other active insn all the way to the end of the basic block. */
269 if (insn
== BB_END (curr_bb
))
276 /* Return the basic block reached by falling though the basic block BB. */
279 block_fallthru (basic_block bb
)
281 edge e
= find_fallthru_edge (bb
->succs
);
283 return (e
) ? e
->dest
: NULL_BLOCK
;
286 /* Go through a bunch of insns, converting them to conditional
287 execution format if possible. Return TRUE if all of the non-note
288 insns were processed. */
291 cond_exec_process_insns (ce_if_block_t
*ce_info ATTRIBUTE_UNUSED
,
292 /* if block information */rtx start
,
293 /* first insn to look at */rtx end
,
294 /* last insn to look at */rtx test
,
295 /* conditional execution test */rtx prob_val
,
296 /* probability of branch taken. */int mod_ok
)
298 int must_be_last
= FALSE
;
306 for (insn
= start
; ; insn
= NEXT_INSN (insn
))
308 /* dwarf2out can't cope with conditional prologues. */
309 if (NOTE_P (insn
) && NOTE_KIND (insn
) == NOTE_INSN_PROLOGUE_END
)
312 if (NOTE_P (insn
) || DEBUG_INSN_P (insn
))
315 gcc_assert(NONJUMP_INSN_P (insn
) || CALL_P (insn
));
317 /* Remove USE insns that get in the way. */
318 if (reload_completed
&& GET_CODE (PATTERN (insn
)) == USE
)
320 /* ??? Ug. Actually unlinking the thing is problematic,
321 given what we'd have to coordinate with our callers. */
322 SET_INSN_DELETED (insn
);
326 /* Last insn wasn't last? */
330 if (modified_in_p (test
, insn
))
337 /* Now build the conditional form of the instruction. */
338 pattern
= PATTERN (insn
);
339 xtest
= copy_rtx (test
);
341 /* If this is already a COND_EXEC, rewrite the test to be an AND of the
343 if (GET_CODE (pattern
) == COND_EXEC
)
345 if (GET_MODE (xtest
) != GET_MODE (COND_EXEC_TEST (pattern
)))
348 xtest
= gen_rtx_AND (GET_MODE (xtest
), xtest
,
349 COND_EXEC_TEST (pattern
));
350 pattern
= COND_EXEC_CODE (pattern
);
353 pattern
= gen_rtx_COND_EXEC (VOIDmode
, xtest
, pattern
);
355 /* If the machine needs to modify the insn being conditionally executed,
356 say for example to force a constant integer operand into a temp
357 register, do so here. */
358 #ifdef IFCVT_MODIFY_INSN
359 IFCVT_MODIFY_INSN (ce_info
, pattern
, insn
);
364 validate_change (insn
, &PATTERN (insn
), pattern
, 1);
366 if (CALL_P (insn
) && prob_val
)
367 validate_change (insn
, ®_NOTES (insn
),
368 alloc_EXPR_LIST (REG_BR_PROB
, prob_val
,
369 REG_NOTES (insn
)), 1);
379 /* Return the condition for a jump. Do not do any special processing. */
382 cond_exec_get_condition (rtx jump
)
386 if (any_condjump_p (jump
))
387 test_if
= SET_SRC (pc_set (jump
));
390 cond
= XEXP (test_if
, 0);
392 /* If this branches to JUMP_LABEL when the condition is false,
393 reverse the condition. */
394 if (GET_CODE (XEXP (test_if
, 2)) == LABEL_REF
395 && XEXP (XEXP (test_if
, 2), 0) == JUMP_LABEL (jump
))
397 enum rtx_code rev
= reversed_comparison_code (cond
, jump
);
401 cond
= gen_rtx_fmt_ee (rev
, GET_MODE (cond
), XEXP (cond
, 0),
408 /* Given a simple IF-THEN or IF-THEN-ELSE block, attempt to convert it
409 to conditional execution. Return TRUE if we were successful at
410 converting the block. */
413 cond_exec_process_if_block (ce_if_block_t
* ce_info
,
414 /* if block information */int do_multiple_p
)
416 basic_block test_bb
= ce_info
->test_bb
; /* last test block */
417 basic_block then_bb
= ce_info
->then_bb
; /* THEN */
418 basic_block else_bb
= ce_info
->else_bb
; /* ELSE or NULL */
419 rtx test_expr
; /* expression in IF_THEN_ELSE that is tested */
420 rtx then_start
; /* first insn in THEN block */
421 rtx then_end
; /* last insn + 1 in THEN block */
422 rtx else_start
= NULL_RTX
; /* first insn in ELSE block or NULL */
423 rtx else_end
= NULL_RTX
; /* last insn + 1 in ELSE block */
424 int max
; /* max # of insns to convert. */
425 int then_mod_ok
; /* whether conditional mods are ok in THEN */
426 rtx true_expr
; /* test for else block insns */
427 rtx false_expr
; /* test for then block insns */
428 rtx true_prob_val
; /* probability of else block */
429 rtx false_prob_val
; /* probability of then block */
430 rtx then_last_head
= NULL_RTX
; /* Last match at the head of THEN */
431 rtx else_last_head
= NULL_RTX
; /* Last match at the head of ELSE */
432 rtx then_first_tail
= NULL_RTX
; /* First match at the tail of THEN */
433 rtx else_first_tail
= NULL_RTX
; /* First match at the tail of ELSE */
434 int then_n_insns
, else_n_insns
, n_insns
;
435 enum rtx_code false_code
;
437 /* If test is comprised of && or || elements, and we've failed at handling
438 all of them together, just use the last test if it is the special case of
439 && elements without an ELSE block. */
440 if (!do_multiple_p
&& ce_info
->num_multiple_test_blocks
)
442 if (else_bb
|| ! ce_info
->and_and_p
)
445 ce_info
->test_bb
= test_bb
= ce_info
->last_test_bb
;
446 ce_info
->num_multiple_test_blocks
= 0;
447 ce_info
->num_and_and_blocks
= 0;
448 ce_info
->num_or_or_blocks
= 0;
451 /* Find the conditional jump to the ELSE or JOIN part, and isolate
453 test_expr
= cond_exec_get_condition (BB_END (test_bb
));
457 /* If the conditional jump is more than just a conditional jump,
458 then we can not do conditional execution conversion on this block. */
459 if (! onlyjump_p (BB_END (test_bb
)))
462 /* Collect the bounds of where we're to search, skipping any labels, jumps
463 and notes at the beginning and end of the block. Then count the total
464 number of insns and see if it is small enough to convert. */
465 then_start
= first_active_insn (then_bb
);
466 then_end
= last_active_insn (then_bb
, TRUE
);
467 then_n_insns
= ce_info
->num_then_insns
= count_bb_insns (then_bb
);
468 n_insns
= then_n_insns
;
469 max
= MAX_CONDITIONAL_EXECUTE
;
476 else_start
= first_active_insn (else_bb
);
477 else_end
= last_active_insn (else_bb
, TRUE
);
478 else_n_insns
= ce_info
->num_else_insns
= count_bb_insns (else_bb
);
479 n_insns
+= else_n_insns
;
481 /* Look for matching sequences at the head and tail of the two blocks,
482 and limit the range of insns to be converted if possible. */
483 n_matching
= flow_find_cross_jump (then_bb
, else_bb
,
484 &then_first_tail
, &else_first_tail
);
485 if (then_first_tail
== BB_HEAD (then_bb
))
486 then_start
= then_end
= NULL_RTX
;
487 if (else_first_tail
== BB_HEAD (else_bb
))
488 else_start
= else_end
= NULL_RTX
;
493 then_end
= find_active_insn_before (then_bb
, then_first_tail
);
495 else_end
= find_active_insn_before (else_bb
, else_first_tail
);
496 n_insns
-= 2 * n_matching
;
499 if (then_start
&& else_start
)
501 int longest_match
= MIN (then_n_insns
- n_matching
,
502 else_n_insns
- n_matching
);
504 = flow_find_head_matching_sequence (then_bb
, else_bb
,
513 /* We won't pass the insns in the head sequence to
514 cond_exec_process_insns, so we need to test them here
515 to make sure that they don't clobber the condition. */
516 for (insn
= BB_HEAD (then_bb
);
517 insn
!= NEXT_INSN (then_last_head
);
518 insn
= NEXT_INSN (insn
))
519 if (!LABEL_P (insn
) && !NOTE_P (insn
)
520 && !DEBUG_INSN_P (insn
)
521 && modified_in_p (test_expr
, insn
))
525 if (then_last_head
== then_end
)
526 then_start
= then_end
= NULL_RTX
;
527 if (else_last_head
== else_end
)
528 else_start
= else_end
= NULL_RTX
;
533 then_start
= find_active_insn_after (then_bb
, then_last_head
);
535 else_start
= find_active_insn_after (else_bb
, else_last_head
);
536 n_insns
-= 2 * n_matching
;
544 /* Map test_expr/test_jump into the appropriate MD tests to use on
545 the conditionally executed code. */
547 true_expr
= test_expr
;
549 false_code
= reversed_comparison_code (true_expr
, BB_END (test_bb
));
550 if (false_code
!= UNKNOWN
)
551 false_expr
= gen_rtx_fmt_ee (false_code
, GET_MODE (true_expr
),
552 XEXP (true_expr
, 0), XEXP (true_expr
, 1));
554 false_expr
= NULL_RTX
;
556 #ifdef IFCVT_MODIFY_TESTS
557 /* If the machine description needs to modify the tests, such as setting a
558 conditional execution register from a comparison, it can do so here. */
559 IFCVT_MODIFY_TESTS (ce_info
, true_expr
, false_expr
);
561 /* See if the conversion failed. */
562 if (!true_expr
|| !false_expr
)
566 true_prob_val
= find_reg_note (BB_END (test_bb
), REG_BR_PROB
, NULL_RTX
);
569 true_prob_val
= XEXP (true_prob_val
, 0);
570 false_prob_val
= GEN_INT (REG_BR_PROB_BASE
- INTVAL (true_prob_val
));
573 false_prob_val
= NULL_RTX
;
575 /* If we have && or || tests, do them here. These tests are in the adjacent
576 blocks after the first block containing the test. */
577 if (ce_info
->num_multiple_test_blocks
> 0)
579 basic_block bb
= test_bb
;
580 basic_block last_test_bb
= ce_info
->last_test_bb
;
589 enum rtx_code f_code
;
591 bb
= block_fallthru (bb
);
592 start
= first_active_insn (bb
);
593 end
= last_active_insn (bb
, TRUE
);
595 && ! cond_exec_process_insns (ce_info
, start
, end
, false_expr
,
596 false_prob_val
, FALSE
))
599 /* If the conditional jump is more than just a conditional jump, then
600 we can not do conditional execution conversion on this block. */
601 if (! onlyjump_p (BB_END (bb
)))
604 /* Find the conditional jump and isolate the test. */
605 t
= cond_exec_get_condition (BB_END (bb
));
609 f_code
= reversed_comparison_code (t
, BB_END (bb
));
610 if (f_code
== UNKNOWN
)
613 f
= gen_rtx_fmt_ee (f_code
, GET_MODE (t
), XEXP (t
, 0), XEXP (t
, 1));
614 if (ce_info
->and_and_p
)
616 t
= gen_rtx_AND (GET_MODE (t
), true_expr
, t
);
617 f
= gen_rtx_IOR (GET_MODE (t
), false_expr
, f
);
621 t
= gen_rtx_IOR (GET_MODE (t
), true_expr
, t
);
622 f
= gen_rtx_AND (GET_MODE (t
), false_expr
, f
);
625 /* If the machine description needs to modify the tests, such as
626 setting a conditional execution register from a comparison, it can
628 #ifdef IFCVT_MODIFY_MULTIPLE_TESTS
629 IFCVT_MODIFY_MULTIPLE_TESTS (ce_info
, bb
, t
, f
);
631 /* See if the conversion failed. */
639 while (bb
!= last_test_bb
);
642 /* For IF-THEN-ELSE blocks, we don't allow modifications of the test
643 on then THEN block. */
644 then_mod_ok
= (else_bb
== NULL_BLOCK
);
646 /* Go through the THEN and ELSE blocks converting the insns if possible
647 to conditional execution. */
651 || ! cond_exec_process_insns (ce_info
, then_start
, then_end
,
652 false_expr
, false_prob_val
,
656 if (else_bb
&& else_end
657 && ! cond_exec_process_insns (ce_info
, else_start
, else_end
,
658 true_expr
, true_prob_val
, TRUE
))
661 /* If we cannot apply the changes, fail. Do not go through the normal fail
662 processing, since apply_change_group will call cancel_changes. */
663 if (! apply_change_group ())
665 #ifdef IFCVT_MODIFY_CANCEL
666 /* Cancel any machine dependent changes. */
667 IFCVT_MODIFY_CANCEL (ce_info
);
672 #ifdef IFCVT_MODIFY_FINAL
673 /* Do any machine dependent final modifications. */
674 IFCVT_MODIFY_FINAL (ce_info
);
677 /* Conversion succeeded. */
679 fprintf (dump_file
, "%d insn%s converted to conditional execution.\n",
680 n_insns
, (n_insns
== 1) ? " was" : "s were");
682 /* Merge the blocks! If we had matching sequences, make sure to delete one
683 copy at the appropriate location first: delete the copy in the THEN branch
684 for a tail sequence so that the remaining one is executed last for both
685 branches, and delete the copy in the ELSE branch for a head sequence so
686 that the remaining one is executed first for both branches. */
689 rtx from
= then_first_tail
;
691 from
= find_active_insn_after (then_bb
, from
);
692 delete_insn_chain (from
, BB_END (then_bb
), false);
695 delete_insn_chain (first_active_insn (else_bb
), else_last_head
, false);
697 merge_if_block (ce_info
);
698 cond_exec_changed_p
= TRUE
;
702 #ifdef IFCVT_MODIFY_CANCEL
703 /* Cancel any machine dependent changes. */
704 IFCVT_MODIFY_CANCEL (ce_info
);
711 /* Used by noce_process_if_block to communicate with its subroutines.
713 The subroutines know that A and B may be evaluated freely. They
714 know that X is a register. They should insert new instructions
715 before cond_earliest. */
719 /* The basic blocks that make up the IF-THEN-{ELSE-,}JOIN block. */
720 basic_block test_bb
, then_bb
, else_bb
, join_bb
;
722 /* The jump that ends TEST_BB. */
725 /* The jump condition. */
728 /* New insns should be inserted before this one. */
731 /* Insns in the THEN and ELSE block. There is always just this
732 one insns in those blocks. The insns are single_set insns.
733 If there was no ELSE block, INSN_B is the last insn before
734 COND_EARLIEST, or NULL_RTX. In the former case, the insn
735 operands are still valid, as if INSN_B was moved down below
739 /* The SET_SRC of INSN_A and INSN_B. */
742 /* The SET_DEST of INSN_A. */
745 /* True if this if block is not canonical. In the canonical form of
746 if blocks, the THEN_BB is the block reached via the fallthru edge
747 from TEST_BB. For the noce transformations, we allow the symmetric
749 bool then_else_reversed
;
751 /* Estimated cost of the particular branch instruction. */
755 static rtx
noce_emit_store_flag (struct noce_if_info
*, rtx
, int, int);
756 static int noce_try_move (struct noce_if_info
*);
757 static int noce_try_store_flag (struct noce_if_info
*);
758 static int noce_try_addcc (struct noce_if_info
*);
759 static int noce_try_store_flag_constants (struct noce_if_info
*);
760 static int noce_try_store_flag_mask (struct noce_if_info
*);
761 static rtx
noce_emit_cmove (struct noce_if_info
*, rtx
, enum rtx_code
, rtx
,
763 static int noce_try_cmove (struct noce_if_info
*);
764 static int noce_try_cmove_arith (struct noce_if_info
*);
765 static rtx
noce_get_alt_condition (struct noce_if_info
*, rtx
, rtx
*);
766 static int noce_try_minmax (struct noce_if_info
*);
767 static int noce_try_abs (struct noce_if_info
*);
768 static int noce_try_sign_mask (struct noce_if_info
*);
770 /* Helper function for noce_try_store_flag*. */
773 noce_emit_store_flag (struct noce_if_info
*if_info
, rtx x
, int reversep
,
776 rtx cond
= if_info
->cond
;
780 cond_complex
= (! general_operand (XEXP (cond
, 0), VOIDmode
)
781 || ! general_operand (XEXP (cond
, 1), VOIDmode
));
783 /* If earliest == jump, or when the condition is complex, try to
784 build the store_flag insn directly. */
788 rtx set
= pc_set (if_info
->jump
);
789 cond
= XEXP (SET_SRC (set
), 0);
790 if (GET_CODE (XEXP (SET_SRC (set
), 2)) == LABEL_REF
791 && XEXP (XEXP (SET_SRC (set
), 2), 0) == JUMP_LABEL (if_info
->jump
))
792 reversep
= !reversep
;
793 if (if_info
->then_else_reversed
)
794 reversep
= !reversep
;
798 code
= reversed_comparison_code (cond
, if_info
->jump
);
800 code
= GET_CODE (cond
);
802 if ((if_info
->cond_earliest
== if_info
->jump
|| cond_complex
)
803 && (normalize
== 0 || STORE_FLAG_VALUE
== normalize
))
807 tmp
= gen_rtx_fmt_ee (code
, GET_MODE (x
), XEXP (cond
, 0),
809 tmp
= gen_rtx_SET (VOIDmode
, x
, tmp
);
812 tmp
= emit_insn (tmp
);
814 if (recog_memoized (tmp
) >= 0)
820 if_info
->cond_earliest
= if_info
->jump
;
828 /* Don't even try if the comparison operands or the mode of X are weird. */
829 if (cond_complex
|| !SCALAR_INT_MODE_P (GET_MODE (x
)))
832 return emit_store_flag (x
, code
, XEXP (cond
, 0),
833 XEXP (cond
, 1), VOIDmode
,
834 (code
== LTU
|| code
== LEU
835 || code
== GEU
|| code
== GTU
), normalize
);
838 /* Emit instruction to move an rtx, possibly into STRICT_LOW_PART.
839 X is the destination/target and Y is the value to copy. */
842 noce_emit_move_insn (rtx x
, rtx y
)
844 enum machine_mode outmode
;
848 if (GET_CODE (x
) != STRICT_LOW_PART
)
850 rtx seq
, insn
, target
;
854 /* Check that the SET_SRC is reasonable before calling emit_move_insn,
855 otherwise construct a suitable SET pattern ourselves. */
856 insn
= (OBJECT_P (y
) || CONSTANT_P (y
) || GET_CODE (y
) == SUBREG
)
857 ? emit_move_insn (x
, y
)
858 : emit_insn (gen_rtx_SET (VOIDmode
, x
, y
));
862 if (recog_memoized (insn
) <= 0)
864 if (GET_CODE (x
) == ZERO_EXTRACT
)
866 rtx op
= XEXP (x
, 0);
867 unsigned HOST_WIDE_INT size
= INTVAL (XEXP (x
, 1));
868 unsigned HOST_WIDE_INT start
= INTVAL (XEXP (x
, 2));
870 /* store_bit_field expects START to be relative to
871 BYTES_BIG_ENDIAN and adjusts this value for machines with
872 BITS_BIG_ENDIAN != BYTES_BIG_ENDIAN. In order to be able to
873 invoke store_bit_field again it is necessary to have the START
874 value from the first call. */
875 if (BITS_BIG_ENDIAN
!= BYTES_BIG_ENDIAN
)
878 start
= BITS_PER_UNIT
- start
- size
;
881 gcc_assert (REG_P (op
));
882 start
= BITS_PER_WORD
- start
- size
;
886 gcc_assert (start
< (MEM_P (op
) ? BITS_PER_UNIT
: BITS_PER_WORD
));
887 store_bit_field (op
, size
, start
, GET_MODE (x
), y
);
891 switch (GET_RTX_CLASS (GET_CODE (y
)))
894 ot
= code_to_optab
[GET_CODE (y
)];
898 target
= expand_unop (GET_MODE (y
), ot
, XEXP (y
, 0), x
, 0);
899 if (target
!= NULL_RTX
)
902 emit_move_insn (x
, target
);
911 ot
= code_to_optab
[GET_CODE (y
)];
915 target
= expand_binop (GET_MODE (y
), ot
,
916 XEXP (y
, 0), XEXP (y
, 1),
918 if (target
!= NULL_RTX
)
921 emit_move_insn (x
, target
);
938 inner
= XEXP (outer
, 0);
939 outmode
= GET_MODE (outer
);
940 bitpos
= SUBREG_BYTE (outer
) * BITS_PER_UNIT
;
941 store_bit_field (inner
, GET_MODE_BITSIZE (outmode
), bitpos
, outmode
, y
);
944 /* Return sequence of instructions generated by if conversion. This
945 function calls end_sequence() to end the current stream, ensures
946 that are instructions are unshared, recognizable non-jump insns.
947 On failure, this function returns a NULL_RTX. */
950 end_ifcvt_sequence (struct noce_if_info
*if_info
)
953 rtx seq
= get_insns ();
955 set_used_flags (if_info
->x
);
956 set_used_flags (if_info
->cond
);
957 unshare_all_rtl_in_chain (seq
);
960 /* Make sure that all of the instructions emitted are recognizable,
961 and that we haven't introduced a new jump instruction.
962 As an exercise for the reader, build a general mechanism that
963 allows proper placement of required clobbers. */
964 for (insn
= seq
; insn
; insn
= NEXT_INSN (insn
))
966 || recog_memoized (insn
) == -1)
972 /* Convert "if (a != b) x = a; else x = b" into "x = a" and
973 "if (a == b) x = a; else x = b" into "x = b". */
976 noce_try_move (struct noce_if_info
*if_info
)
978 rtx cond
= if_info
->cond
;
979 enum rtx_code code
= GET_CODE (cond
);
982 if (code
!= NE
&& code
!= EQ
)
985 /* This optimization isn't valid if either A or B could be a NaN
987 if (HONOR_NANS (GET_MODE (if_info
->x
))
988 || HONOR_SIGNED_ZEROS (GET_MODE (if_info
->x
)))
991 /* Check whether the operands of the comparison are A and in
993 if ((rtx_equal_p (if_info
->a
, XEXP (cond
, 0))
994 && rtx_equal_p (if_info
->b
, XEXP (cond
, 1)))
995 || (rtx_equal_p (if_info
->a
, XEXP (cond
, 1))
996 && rtx_equal_p (if_info
->b
, XEXP (cond
, 0))))
998 y
= (code
== EQ
) ? if_info
->a
: if_info
->b
;
1000 /* Avoid generating the move if the source is the destination. */
1001 if (! rtx_equal_p (if_info
->x
, y
))
1004 noce_emit_move_insn (if_info
->x
, y
);
1005 seq
= end_ifcvt_sequence (if_info
);
1009 emit_insn_before_setloc (seq
, if_info
->jump
,
1010 INSN_LOCATOR (if_info
->insn_a
));
1017 /* Convert "if (test) x = 1; else x = 0".
1019 Only try 0 and STORE_FLAG_VALUE here. Other combinations will be
1020 tried in noce_try_store_flag_constants after noce_try_cmove has had
1021 a go at the conversion. */
1024 noce_try_store_flag (struct noce_if_info
*if_info
)
1029 if (CONST_INT_P (if_info
->b
)
1030 && INTVAL (if_info
->b
) == STORE_FLAG_VALUE
1031 && if_info
->a
== const0_rtx
)
1033 else if (if_info
->b
== const0_rtx
1034 && CONST_INT_P (if_info
->a
)
1035 && INTVAL (if_info
->a
) == STORE_FLAG_VALUE
1036 && (reversed_comparison_code (if_info
->cond
, if_info
->jump
)
1044 target
= noce_emit_store_flag (if_info
, if_info
->x
, reversep
, 0);
1047 if (target
!= if_info
->x
)
1048 noce_emit_move_insn (if_info
->x
, target
);
1050 seq
= end_ifcvt_sequence (if_info
);
1054 emit_insn_before_setloc (seq
, if_info
->jump
,
1055 INSN_LOCATOR (if_info
->insn_a
));
1065 /* Convert "if (test) x = a; else x = b", for A and B constant. */
1068 noce_try_store_flag_constants (struct noce_if_info
*if_info
)
1072 HOST_WIDE_INT itrue
, ifalse
, diff
, tmp
;
1073 int normalize
, can_reverse
;
1074 enum machine_mode mode
;
1076 if (CONST_INT_P (if_info
->a
)
1077 && CONST_INT_P (if_info
->b
))
1079 mode
= GET_MODE (if_info
->x
);
1080 ifalse
= INTVAL (if_info
->a
);
1081 itrue
= INTVAL (if_info
->b
);
1083 /* Make sure we can represent the difference between the two values. */
1084 if ((itrue
- ifalse
> 0)
1085 != ((ifalse
< 0) != (itrue
< 0) ? ifalse
< 0 : ifalse
< itrue
))
1088 diff
= trunc_int_for_mode (itrue
- ifalse
, mode
);
1090 can_reverse
= (reversed_comparison_code (if_info
->cond
, if_info
->jump
)
1094 if (diff
== STORE_FLAG_VALUE
|| diff
== -STORE_FLAG_VALUE
)
1096 else if (ifalse
== 0 && exact_log2 (itrue
) >= 0
1097 && (STORE_FLAG_VALUE
== 1
1098 || if_info
->branch_cost
>= 2))
1100 else if (itrue
== 0 && exact_log2 (ifalse
) >= 0 && can_reverse
1101 && (STORE_FLAG_VALUE
== 1 || if_info
->branch_cost
>= 2))
1102 normalize
= 1, reversep
= 1;
1103 else if (itrue
== -1
1104 && (STORE_FLAG_VALUE
== -1
1105 || if_info
->branch_cost
>= 2))
1107 else if (ifalse
== -1 && can_reverse
1108 && (STORE_FLAG_VALUE
== -1 || if_info
->branch_cost
>= 2))
1109 normalize
= -1, reversep
= 1;
1110 else if ((if_info
->branch_cost
>= 2 && STORE_FLAG_VALUE
== -1)
1111 || if_info
->branch_cost
>= 3)
1118 tmp
= itrue
; itrue
= ifalse
; ifalse
= tmp
;
1119 diff
= trunc_int_for_mode (-diff
, mode
);
1123 target
= noce_emit_store_flag (if_info
, if_info
->x
, reversep
, normalize
);
1130 /* if (test) x = 3; else x = 4;
1131 => x = 3 + (test == 0); */
1132 if (diff
== STORE_FLAG_VALUE
|| diff
== -STORE_FLAG_VALUE
)
1134 target
= expand_simple_binop (mode
,
1135 (diff
== STORE_FLAG_VALUE
1137 GEN_INT (ifalse
), target
, if_info
->x
, 0,
1141 /* if (test) x = 8; else x = 0;
1142 => x = (test != 0) << 3; */
1143 else if (ifalse
== 0 && (tmp
= exact_log2 (itrue
)) >= 0)
1145 target
= expand_simple_binop (mode
, ASHIFT
,
1146 target
, GEN_INT (tmp
), if_info
->x
, 0,
1150 /* if (test) x = -1; else x = b;
1151 => x = -(test != 0) | b; */
1152 else if (itrue
== -1)
1154 target
= expand_simple_binop (mode
, IOR
,
1155 target
, GEN_INT (ifalse
), if_info
->x
, 0,
1159 /* if (test) x = a; else x = b;
1160 => x = (-(test != 0) & (b - a)) + a; */
1163 target
= expand_simple_binop (mode
, AND
,
1164 target
, GEN_INT (diff
), if_info
->x
, 0,
1167 target
= expand_simple_binop (mode
, PLUS
,
1168 target
, GEN_INT (ifalse
),
1169 if_info
->x
, 0, OPTAB_WIDEN
);
1178 if (target
!= if_info
->x
)
1179 noce_emit_move_insn (if_info
->x
, target
);
1181 seq
= end_ifcvt_sequence (if_info
);
1185 emit_insn_before_setloc (seq
, if_info
->jump
,
1186 INSN_LOCATOR (if_info
->insn_a
));
1193 /* Convert "if (test) foo++" into "foo += (test != 0)", and
1194 similarly for "foo--". */
1197 noce_try_addcc (struct noce_if_info
*if_info
)
1200 int subtract
, normalize
;
1202 if (GET_CODE (if_info
->a
) == PLUS
1203 && rtx_equal_p (XEXP (if_info
->a
, 0), if_info
->b
)
1204 && (reversed_comparison_code (if_info
->cond
, if_info
->jump
)
1207 rtx cond
= if_info
->cond
;
1208 enum rtx_code code
= reversed_comparison_code (cond
, if_info
->jump
);
1210 /* First try to use addcc pattern. */
1211 if (general_operand (XEXP (cond
, 0), VOIDmode
)
1212 && general_operand (XEXP (cond
, 1), VOIDmode
))
1215 target
= emit_conditional_add (if_info
->x
, code
,
1220 XEXP (if_info
->a
, 1),
1221 GET_MODE (if_info
->x
),
1222 (code
== LTU
|| code
== GEU
1223 || code
== LEU
|| code
== GTU
));
1226 if (target
!= if_info
->x
)
1227 noce_emit_move_insn (if_info
->x
, target
);
1229 seq
= end_ifcvt_sequence (if_info
);
1233 emit_insn_before_setloc (seq
, if_info
->jump
,
1234 INSN_LOCATOR (if_info
->insn_a
));
1240 /* If that fails, construct conditional increment or decrement using
1242 if (if_info
->branch_cost
>= 2
1243 && (XEXP (if_info
->a
, 1) == const1_rtx
1244 || XEXP (if_info
->a
, 1) == constm1_rtx
))
1247 if (STORE_FLAG_VALUE
== INTVAL (XEXP (if_info
->a
, 1)))
1248 subtract
= 0, normalize
= 0;
1249 else if (-STORE_FLAG_VALUE
== INTVAL (XEXP (if_info
->a
, 1)))
1250 subtract
= 1, normalize
= 0;
1252 subtract
= 0, normalize
= INTVAL (XEXP (if_info
->a
, 1));
1255 target
= noce_emit_store_flag (if_info
,
1256 gen_reg_rtx (GET_MODE (if_info
->x
)),
1260 target
= expand_simple_binop (GET_MODE (if_info
->x
),
1261 subtract
? MINUS
: PLUS
,
1262 if_info
->b
, target
, if_info
->x
,
1266 if (target
!= if_info
->x
)
1267 noce_emit_move_insn (if_info
->x
, target
);
1269 seq
= end_ifcvt_sequence (if_info
);
1273 emit_insn_before_setloc (seq
, if_info
->jump
,
1274 INSN_LOCATOR (if_info
->insn_a
));
1284 /* Convert "if (test) x = 0;" to "x &= -(test == 0);" */
1287 noce_try_store_flag_mask (struct noce_if_info
*if_info
)
1293 if ((if_info
->branch_cost
>= 2
1294 || STORE_FLAG_VALUE
== -1)
1295 && ((if_info
->a
== const0_rtx
1296 && rtx_equal_p (if_info
->b
, if_info
->x
))
1297 || ((reversep
= (reversed_comparison_code (if_info
->cond
,
1300 && if_info
->b
== const0_rtx
1301 && rtx_equal_p (if_info
->a
, if_info
->x
))))
1304 target
= noce_emit_store_flag (if_info
,
1305 gen_reg_rtx (GET_MODE (if_info
->x
)),
1308 target
= expand_simple_binop (GET_MODE (if_info
->x
), AND
,
1310 target
, if_info
->x
, 0,
1315 if (target
!= if_info
->x
)
1316 noce_emit_move_insn (if_info
->x
, target
);
1318 seq
= end_ifcvt_sequence (if_info
);
1322 emit_insn_before_setloc (seq
, if_info
->jump
,
1323 INSN_LOCATOR (if_info
->insn_a
));
1333 /* Helper function for noce_try_cmove and noce_try_cmove_arith. */
1336 noce_emit_cmove (struct noce_if_info
*if_info
, rtx x
, enum rtx_code code
,
1337 rtx cmp_a
, rtx cmp_b
, rtx vfalse
, rtx vtrue
)
1339 rtx target ATTRIBUTE_UNUSED
;
1340 int unsignedp ATTRIBUTE_UNUSED
;
1342 /* If earliest == jump, try to build the cmove insn directly.
1343 This is helpful when combine has created some complex condition
1344 (like for alpha's cmovlbs) that we can't hope to regenerate
1345 through the normal interface. */
1347 if (if_info
->cond_earliest
== if_info
->jump
)
1351 tmp
= gen_rtx_fmt_ee (code
, GET_MODE (if_info
->cond
), cmp_a
, cmp_b
);
1352 tmp
= gen_rtx_IF_THEN_ELSE (GET_MODE (x
), tmp
, vtrue
, vfalse
);
1353 tmp
= gen_rtx_SET (VOIDmode
, x
, tmp
);
1356 tmp
= emit_insn (tmp
);
1358 if (recog_memoized (tmp
) >= 0)
1370 /* Don't even try if the comparison operands are weird. */
1371 if (! general_operand (cmp_a
, GET_MODE (cmp_a
))
1372 || ! general_operand (cmp_b
, GET_MODE (cmp_b
)))
1375 #if HAVE_conditional_move
1376 unsignedp
= (code
== LTU
|| code
== GEU
1377 || code
== LEU
|| code
== GTU
);
1379 target
= emit_conditional_move (x
, code
, cmp_a
, cmp_b
, VOIDmode
,
1380 vtrue
, vfalse
, GET_MODE (x
),
1385 /* We might be faced with a situation like:
1388 vtrue = (subreg:M (reg:N VTRUE) BYTE)
1389 vfalse = (subreg:M (reg:N VFALSE) BYTE)
1391 We can't do a conditional move in mode M, but it's possible that we
1392 could do a conditional move in mode N instead and take a subreg of
1395 If we can't create new pseudos, though, don't bother. */
1396 if (reload_completed
)
1399 if (GET_CODE (vtrue
) == SUBREG
&& GET_CODE (vfalse
) == SUBREG
)
1401 rtx reg_vtrue
= SUBREG_REG (vtrue
);
1402 rtx reg_vfalse
= SUBREG_REG (vfalse
);
1403 unsigned int byte_vtrue
= SUBREG_BYTE (vtrue
);
1404 unsigned int byte_vfalse
= SUBREG_BYTE (vfalse
);
1405 rtx promoted_target
;
1407 if (GET_MODE (reg_vtrue
) != GET_MODE (reg_vfalse
)
1408 || byte_vtrue
!= byte_vfalse
1409 || (SUBREG_PROMOTED_VAR_P (vtrue
)
1410 != SUBREG_PROMOTED_VAR_P (vfalse
))
1411 || (SUBREG_PROMOTED_UNSIGNED_P (vtrue
)
1412 != SUBREG_PROMOTED_UNSIGNED_P (vfalse
)))
1415 promoted_target
= gen_reg_rtx (GET_MODE (reg_vtrue
));
1417 target
= emit_conditional_move (promoted_target
, code
, cmp_a
, cmp_b
,
1418 VOIDmode
, reg_vtrue
, reg_vfalse
,
1419 GET_MODE (reg_vtrue
), unsignedp
);
1420 /* Nope, couldn't do it in that mode either. */
1424 target
= gen_rtx_SUBREG (GET_MODE (vtrue
), promoted_target
, byte_vtrue
);
1425 SUBREG_PROMOTED_VAR_P (target
) = SUBREG_PROMOTED_VAR_P (vtrue
);
1426 SUBREG_PROMOTED_UNSIGNED_SET (target
, SUBREG_PROMOTED_UNSIGNED_P (vtrue
));
1427 emit_move_insn (x
, target
);
1433 /* We'll never get here, as noce_process_if_block doesn't call the
1434 functions involved. Ifdef code, however, should be discouraged
1435 because it leads to typos in the code not selected. However,
1436 emit_conditional_move won't exist either. */
1441 /* Try only simple constants and registers here. More complex cases
1442 are handled in noce_try_cmove_arith after noce_try_store_flag_arith
1443 has had a go at it. */
1446 noce_try_cmove (struct noce_if_info
*if_info
)
1451 if ((CONSTANT_P (if_info
->a
) || register_operand (if_info
->a
, VOIDmode
))
1452 && (CONSTANT_P (if_info
->b
) || register_operand (if_info
->b
, VOIDmode
)))
1456 code
= GET_CODE (if_info
->cond
);
1457 target
= noce_emit_cmove (if_info
, if_info
->x
, code
,
1458 XEXP (if_info
->cond
, 0),
1459 XEXP (if_info
->cond
, 1),
1460 if_info
->a
, if_info
->b
);
1464 if (target
!= if_info
->x
)
1465 noce_emit_move_insn (if_info
->x
, target
);
1467 seq
= end_ifcvt_sequence (if_info
);
1471 emit_insn_before_setloc (seq
, if_info
->jump
,
1472 INSN_LOCATOR (if_info
->insn_a
));
1485 /* Try more complex cases involving conditional_move. */
1488 noce_try_cmove_arith (struct noce_if_info
*if_info
)
1500 /* A conditional move from two memory sources is equivalent to a
1501 conditional on their addresses followed by a load. Don't do this
1502 early because it'll screw alias analysis. Note that we've
1503 already checked for no side effects. */
1504 /* ??? FIXME: Magic number 5. */
1505 if (cse_not_expected
1506 && MEM_P (a
) && MEM_P (b
)
1507 && MEM_ADDR_SPACE (a
) == MEM_ADDR_SPACE (b
)
1508 && if_info
->branch_cost
>= 5)
1510 enum machine_mode address_mode
1511 = targetm
.addr_space
.address_mode (MEM_ADDR_SPACE (a
));
1515 x
= gen_reg_rtx (address_mode
);
1519 /* ??? We could handle this if we knew that a load from A or B could
1520 not fault. This is also true if we've already loaded
1521 from the address along the path from ENTRY. */
1522 else if (may_trap_p (a
) || may_trap_p (b
))
1525 /* if (test) x = a + b; else x = c - d;
1532 code
= GET_CODE (if_info
->cond
);
1533 insn_a
= if_info
->insn_a
;
1534 insn_b
= if_info
->insn_b
;
1536 /* Total insn_rtx_cost should be smaller than branch cost. Exit
1537 if insn_rtx_cost can't be estimated. */
1541 = insn_rtx_cost (PATTERN (insn_a
),
1542 optimize_bb_for_speed_p (BLOCK_FOR_INSN (insn_a
)));
1543 if (insn_cost
== 0 || insn_cost
> COSTS_N_INSNS (if_info
->branch_cost
))
1552 += insn_rtx_cost (PATTERN (insn_b
),
1553 optimize_bb_for_speed_p (BLOCK_FOR_INSN (insn_b
)));
1554 if (insn_cost
== 0 || insn_cost
> COSTS_N_INSNS (if_info
->branch_cost
))
1558 /* Possibly rearrange operands to make things come out more natural. */
1559 if (reversed_comparison_code (if_info
->cond
, if_info
->jump
) != UNKNOWN
)
1562 if (rtx_equal_p (b
, x
))
1564 else if (general_operand (b
, GET_MODE (b
)))
1569 code
= reversed_comparison_code (if_info
->cond
, if_info
->jump
);
1570 tmp
= a
, a
= b
, b
= tmp
;
1571 tmp
= insn_a
, insn_a
= insn_b
, insn_b
= tmp
;
1580 /* If either operand is complex, load it into a register first.
1581 The best way to do this is to copy the original insn. In this
1582 way we preserve any clobbers etc that the insn may have had.
1583 This is of course not possible in the IS_MEM case. */
1584 if (! general_operand (a
, GET_MODE (a
)))
1590 tmp
= gen_reg_rtx (GET_MODE (a
));
1591 tmp
= emit_insn (gen_rtx_SET (VOIDmode
, tmp
, a
));
1594 goto end_seq_and_fail
;
1597 a
= gen_reg_rtx (GET_MODE (a
));
1598 tmp
= copy_rtx (insn_a
);
1599 set
= single_set (tmp
);
1601 tmp
= emit_insn (PATTERN (tmp
));
1603 if (recog_memoized (tmp
) < 0)
1604 goto end_seq_and_fail
;
1606 if (! general_operand (b
, GET_MODE (b
)))
1612 tmp
= gen_reg_rtx (GET_MODE (b
));
1613 tmp
= gen_rtx_SET (VOIDmode
, tmp
, b
);
1616 goto end_seq_and_fail
;
1619 b
= gen_reg_rtx (GET_MODE (b
));
1620 tmp
= copy_rtx (insn_b
);
1621 set
= single_set (tmp
);
1623 tmp
= PATTERN (tmp
);
1626 /* If insn to set up A clobbers any registers B depends on, try to
1627 swap insn that sets up A with the one that sets up B. If even
1628 that doesn't help, punt. */
1629 last
= get_last_insn ();
1630 if (last
&& modified_in_p (orig_b
, last
))
1632 tmp
= emit_insn_before (tmp
, get_insns ());
1633 if (modified_in_p (orig_a
, tmp
))
1634 goto end_seq_and_fail
;
1637 tmp
= emit_insn (tmp
);
1639 if (recog_memoized (tmp
) < 0)
1640 goto end_seq_and_fail
;
1643 target
= noce_emit_cmove (if_info
, x
, code
, XEXP (if_info
->cond
, 0),
1644 XEXP (if_info
->cond
, 1), a
, b
);
1647 goto end_seq_and_fail
;
1649 /* If we're handling a memory for above, emit the load now. */
1652 tmp
= gen_rtx_MEM (GET_MODE (if_info
->x
), target
);
1654 /* Copy over flags as appropriate. */
1655 if (MEM_VOLATILE_P (if_info
->a
) || MEM_VOLATILE_P (if_info
->b
))
1656 MEM_VOLATILE_P (tmp
) = 1;
1657 if (MEM_IN_STRUCT_P (if_info
->a
) && MEM_IN_STRUCT_P (if_info
->b
))
1658 MEM_IN_STRUCT_P (tmp
) = 1;
1659 if (MEM_SCALAR_P (if_info
->a
) && MEM_SCALAR_P (if_info
->b
))
1660 MEM_SCALAR_P (tmp
) = 1;
1661 if (MEM_ALIAS_SET (if_info
->a
) == MEM_ALIAS_SET (if_info
->b
))
1662 set_mem_alias_set (tmp
, MEM_ALIAS_SET (if_info
->a
));
1664 MIN (MEM_ALIGN (if_info
->a
), MEM_ALIGN (if_info
->b
)));
1666 gcc_assert (MEM_ADDR_SPACE (if_info
->a
) == MEM_ADDR_SPACE (if_info
->b
));
1667 set_mem_addr_space (tmp
, MEM_ADDR_SPACE (if_info
->a
));
1669 noce_emit_move_insn (if_info
->x
, tmp
);
1671 else if (target
!= x
)
1672 noce_emit_move_insn (x
, target
);
1674 tmp
= end_ifcvt_sequence (if_info
);
1678 emit_insn_before_setloc (tmp
, if_info
->jump
, INSN_LOCATOR (if_info
->insn_a
));
1686 /* For most cases, the simplified condition we found is the best
1687 choice, but this is not the case for the min/max/abs transforms.
1688 For these we wish to know that it is A or B in the condition. */
1691 noce_get_alt_condition (struct noce_if_info
*if_info
, rtx target
,
1694 rtx cond
, set
, insn
;
1697 /* If target is already mentioned in the known condition, return it. */
1698 if (reg_mentioned_p (target
, if_info
->cond
))
1700 *earliest
= if_info
->cond_earliest
;
1701 return if_info
->cond
;
1704 set
= pc_set (if_info
->jump
);
1705 cond
= XEXP (SET_SRC (set
), 0);
1707 = GET_CODE (XEXP (SET_SRC (set
), 2)) == LABEL_REF
1708 && XEXP (XEXP (SET_SRC (set
), 2), 0) == JUMP_LABEL (if_info
->jump
);
1709 if (if_info
->then_else_reversed
)
1712 /* If we're looking for a constant, try to make the conditional
1713 have that constant in it. There are two reasons why it may
1714 not have the constant we want:
1716 1. GCC may have needed to put the constant in a register, because
1717 the target can't compare directly against that constant. For
1718 this case, we look for a SET immediately before the comparison
1719 that puts a constant in that register.
1721 2. GCC may have canonicalized the conditional, for example
1722 replacing "if x < 4" with "if x <= 3". We can undo that (or
1723 make equivalent types of changes) to get the constants we need
1724 if they're off by one in the right direction. */
1726 if (CONST_INT_P (target
))
1728 enum rtx_code code
= GET_CODE (if_info
->cond
);
1729 rtx op_a
= XEXP (if_info
->cond
, 0);
1730 rtx op_b
= XEXP (if_info
->cond
, 1);
1733 /* First, look to see if we put a constant in a register. */
1734 prev_insn
= prev_nonnote_insn (if_info
->cond_earliest
);
1736 && BLOCK_FOR_INSN (prev_insn
)
1737 == BLOCK_FOR_INSN (if_info
->cond_earliest
)
1738 && INSN_P (prev_insn
)
1739 && GET_CODE (PATTERN (prev_insn
)) == SET
)
1741 rtx src
= find_reg_equal_equiv_note (prev_insn
);
1743 src
= SET_SRC (PATTERN (prev_insn
));
1744 if (CONST_INT_P (src
))
1746 if (rtx_equal_p (op_a
, SET_DEST (PATTERN (prev_insn
))))
1748 else if (rtx_equal_p (op_b
, SET_DEST (PATTERN (prev_insn
))))
1751 if (CONST_INT_P (op_a
))
1756 code
= swap_condition (code
);
1761 /* Now, look to see if we can get the right constant by
1762 adjusting the conditional. */
1763 if (CONST_INT_P (op_b
))
1765 HOST_WIDE_INT desired_val
= INTVAL (target
);
1766 HOST_WIDE_INT actual_val
= INTVAL (op_b
);
1771 if (actual_val
== desired_val
+ 1)
1774 op_b
= GEN_INT (desired_val
);
1778 if (actual_val
== desired_val
- 1)
1781 op_b
= GEN_INT (desired_val
);
1785 if (actual_val
== desired_val
- 1)
1788 op_b
= GEN_INT (desired_val
);
1792 if (actual_val
== desired_val
+ 1)
1795 op_b
= GEN_INT (desired_val
);
1803 /* If we made any changes, generate a new conditional that is
1804 equivalent to what we started with, but has the right
1806 if (code
!= GET_CODE (if_info
->cond
)
1807 || op_a
!= XEXP (if_info
->cond
, 0)
1808 || op_b
!= XEXP (if_info
->cond
, 1))
1810 cond
= gen_rtx_fmt_ee (code
, GET_MODE (cond
), op_a
, op_b
);
1811 *earliest
= if_info
->cond_earliest
;
1816 cond
= canonicalize_condition (if_info
->jump
, cond
, reverse
,
1817 earliest
, target
, false, true);
1818 if (! cond
|| ! reg_mentioned_p (target
, cond
))
1821 /* We almost certainly searched back to a different place.
1822 Need to re-verify correct lifetimes. */
1824 /* X may not be mentioned in the range (cond_earliest, jump]. */
1825 for (insn
= if_info
->jump
; insn
!= *earliest
; insn
= PREV_INSN (insn
))
1826 if (INSN_P (insn
) && reg_overlap_mentioned_p (if_info
->x
, PATTERN (insn
)))
1829 /* A and B may not be modified in the range [cond_earliest, jump). */
1830 for (insn
= *earliest
; insn
!= if_info
->jump
; insn
= NEXT_INSN (insn
))
1832 && (modified_in_p (if_info
->a
, insn
)
1833 || modified_in_p (if_info
->b
, insn
)))
1839 /* Convert "if (a < b) x = a; else x = b;" to "x = min(a, b);", etc. */
1842 noce_try_minmax (struct noce_if_info
*if_info
)
1844 rtx cond
, earliest
, target
, seq
;
1845 enum rtx_code code
, op
;
1848 /* ??? Reject modes with NaNs or signed zeros since we don't know how
1849 they will be resolved with an SMIN/SMAX. It wouldn't be too hard
1850 to get the target to tell us... */
1851 if (HONOR_SIGNED_ZEROS (GET_MODE (if_info
->x
))
1852 || HONOR_NANS (GET_MODE (if_info
->x
)))
1855 cond
= noce_get_alt_condition (if_info
, if_info
->a
, &earliest
);
1859 /* Verify the condition is of the form we expect, and canonicalize
1860 the comparison code. */
1861 code
= GET_CODE (cond
);
1862 if (rtx_equal_p (XEXP (cond
, 0), if_info
->a
))
1864 if (! rtx_equal_p (XEXP (cond
, 1), if_info
->b
))
1867 else if (rtx_equal_p (XEXP (cond
, 1), if_info
->a
))
1869 if (! rtx_equal_p (XEXP (cond
, 0), if_info
->b
))
1871 code
= swap_condition (code
);
1876 /* Determine what sort of operation this is. Note that the code is for
1877 a taken branch, so the code->operation mapping appears backwards. */
1910 target
= expand_simple_binop (GET_MODE (if_info
->x
), op
,
1911 if_info
->a
, if_info
->b
,
1912 if_info
->x
, unsignedp
, OPTAB_WIDEN
);
1918 if (target
!= if_info
->x
)
1919 noce_emit_move_insn (if_info
->x
, target
);
1921 seq
= end_ifcvt_sequence (if_info
);
1925 emit_insn_before_setloc (seq
, if_info
->jump
, INSN_LOCATOR (if_info
->insn_a
));
1926 if_info
->cond
= cond
;
1927 if_info
->cond_earliest
= earliest
;
1932 /* Convert "if (a < 0) x = -a; else x = a;" to "x = abs(a);",
1933 "if (a < 0) x = ~a; else x = a;" to "x = one_cmpl_abs(a);",
1937 noce_try_abs (struct noce_if_info
*if_info
)
1939 rtx cond
, earliest
, target
, seq
, a
, b
, c
;
1941 bool one_cmpl
= false;
1943 /* Reject modes with signed zeros. */
1944 if (HONOR_SIGNED_ZEROS (GET_MODE (if_info
->x
)))
1947 /* Recognize A and B as constituting an ABS or NABS. The canonical
1948 form is a branch around the negation, taken when the object is the
1949 first operand of a comparison against 0 that evaluates to true. */
1952 if (GET_CODE (a
) == NEG
&& rtx_equal_p (XEXP (a
, 0), b
))
1954 else if (GET_CODE (b
) == NEG
&& rtx_equal_p (XEXP (b
, 0), a
))
1956 c
= a
; a
= b
; b
= c
;
1959 else if (GET_CODE (a
) == NOT
&& rtx_equal_p (XEXP (a
, 0), b
))
1964 else if (GET_CODE (b
) == NOT
&& rtx_equal_p (XEXP (b
, 0), a
))
1966 c
= a
; a
= b
; b
= c
;
1973 cond
= noce_get_alt_condition (if_info
, b
, &earliest
);
1977 /* Verify the condition is of the form we expect. */
1978 if (rtx_equal_p (XEXP (cond
, 0), b
))
1980 else if (rtx_equal_p (XEXP (cond
, 1), b
))
1988 /* Verify that C is zero. Search one step backward for a
1989 REG_EQUAL note or a simple source if necessary. */
1992 rtx set
, insn
= prev_nonnote_insn (earliest
);
1994 && BLOCK_FOR_INSN (insn
) == BLOCK_FOR_INSN (earliest
)
1995 && (set
= single_set (insn
))
1996 && rtx_equal_p (SET_DEST (set
), c
))
1998 rtx note
= find_reg_equal_equiv_note (insn
);
2008 && GET_CODE (XEXP (c
, 0)) == SYMBOL_REF
2009 && CONSTANT_POOL_ADDRESS_P (XEXP (c
, 0)))
2010 c
= get_pool_constant (XEXP (c
, 0));
2012 /* Work around funny ideas get_condition has wrt canonicalization.
2013 Note that these rtx constants are known to be CONST_INT, and
2014 therefore imply integer comparisons. */
2015 if (c
== constm1_rtx
&& GET_CODE (cond
) == GT
)
2017 else if (c
== const1_rtx
&& GET_CODE (cond
) == LT
)
2019 else if (c
!= CONST0_RTX (GET_MODE (b
)))
2022 /* Determine what sort of operation this is. */
2023 switch (GET_CODE (cond
))
2042 target
= expand_one_cmpl_abs_nojump (GET_MODE (if_info
->x
), b
,
2045 target
= expand_abs_nojump (GET_MODE (if_info
->x
), b
, if_info
->x
, 1);
2047 /* ??? It's a quandary whether cmove would be better here, especially
2048 for integers. Perhaps combine will clean things up. */
2049 if (target
&& negate
)
2052 target
= expand_simple_unop (GET_MODE (target
), NOT
, target
,
2055 target
= expand_simple_unop (GET_MODE (target
), NEG
, target
,
2065 if (target
!= if_info
->x
)
2066 noce_emit_move_insn (if_info
->x
, target
);
2068 seq
= end_ifcvt_sequence (if_info
);
2072 emit_insn_before_setloc (seq
, if_info
->jump
, INSN_LOCATOR (if_info
->insn_a
));
2073 if_info
->cond
= cond
;
2074 if_info
->cond_earliest
= earliest
;
2079 /* Convert "if (m < 0) x = b; else x = 0;" to "x = (m >> C) & b;". */
2082 noce_try_sign_mask (struct noce_if_info
*if_info
)
2084 rtx cond
, t
, m
, c
, seq
;
2085 enum machine_mode mode
;
2087 bool t_unconditional
;
2089 cond
= if_info
->cond
;
2090 code
= GET_CODE (cond
);
2095 if (if_info
->a
== const0_rtx
)
2097 if ((code
== LT
&& c
== const0_rtx
)
2098 || (code
== LE
&& c
== constm1_rtx
))
2101 else if (if_info
->b
== const0_rtx
)
2103 if ((code
== GE
&& c
== const0_rtx
)
2104 || (code
== GT
&& c
== constm1_rtx
))
2108 if (! t
|| side_effects_p (t
))
2111 /* We currently don't handle different modes. */
2112 mode
= GET_MODE (t
);
2113 if (GET_MODE (m
) != mode
)
2116 /* This is only profitable if T is unconditionally executed/evaluated in the
2117 original insn sequence or T is cheap. The former happens if B is the
2118 non-zero (T) value and if INSN_B was taken from TEST_BB, or there was no
2119 INSN_B which can happen for e.g. conditional stores to memory. For the
2120 cost computation use the block TEST_BB where the evaluation will end up
2121 after the transformation. */
2124 && (if_info
->insn_b
== NULL_RTX
2125 || BLOCK_FOR_INSN (if_info
->insn_b
) == if_info
->test_bb
));
2126 if (!(t_unconditional
2127 || (rtx_cost (t
, SET
, optimize_bb_for_speed_p (if_info
->test_bb
))
2128 < COSTS_N_INSNS (2))))
2132 /* Use emit_store_flag to generate "m < 0 ? -1 : 0" instead of expanding
2133 "(signed) m >> 31" directly. This benefits targets with specialized
2134 insns to obtain the signmask, but still uses ashr_optab otherwise. */
2135 m
= emit_store_flag (gen_reg_rtx (mode
), LT
, m
, const0_rtx
, mode
, 0, -1);
2136 t
= m
? expand_binop (mode
, and_optab
, m
, t
, NULL_RTX
, 0, OPTAB_DIRECT
)
2145 noce_emit_move_insn (if_info
->x
, t
);
2147 seq
= end_ifcvt_sequence (if_info
);
2151 emit_insn_before_setloc (seq
, if_info
->jump
, INSN_LOCATOR (if_info
->insn_a
));
2156 /* Optimize away "if (x & C) x |= C" and similar bit manipulation
2160 noce_try_bitop (struct noce_if_info
*if_info
)
2162 rtx cond
, x
, a
, result
, seq
;
2163 enum machine_mode mode
;
2168 cond
= if_info
->cond
;
2169 code
= GET_CODE (cond
);
2171 /* Check for no else condition. */
2172 if (! rtx_equal_p (x
, if_info
->b
))
2175 /* Check for a suitable condition. */
2176 if (code
!= NE
&& code
!= EQ
)
2178 if (XEXP (cond
, 1) != const0_rtx
)
2180 cond
= XEXP (cond
, 0);
2182 /* ??? We could also handle AND here. */
2183 if (GET_CODE (cond
) == ZERO_EXTRACT
)
2185 if (XEXP (cond
, 1) != const1_rtx
2186 || !CONST_INT_P (XEXP (cond
, 2))
2187 || ! rtx_equal_p (x
, XEXP (cond
, 0)))
2189 bitnum
= INTVAL (XEXP (cond
, 2));
2190 mode
= GET_MODE (x
);
2191 if (BITS_BIG_ENDIAN
)
2192 bitnum
= GET_MODE_BITSIZE (mode
) - 1 - bitnum
;
2193 if (bitnum
< 0 || bitnum
>= HOST_BITS_PER_WIDE_INT
)
2200 if (GET_CODE (a
) == IOR
|| GET_CODE (a
) == XOR
)
2202 /* Check for "if (X & C) x = x op C". */
2203 if (! rtx_equal_p (x
, XEXP (a
, 0))
2204 || !CONST_INT_P (XEXP (a
, 1))
2205 || (INTVAL (XEXP (a
, 1)) & GET_MODE_MASK (mode
))
2206 != (unsigned HOST_WIDE_INT
) 1 << bitnum
)
2209 /* if ((x & C) == 0) x |= C; is transformed to x |= C. */
2210 /* if ((x & C) != 0) x |= C; is transformed to nothing. */
2211 if (GET_CODE (a
) == IOR
)
2212 result
= (code
== NE
) ? a
: NULL_RTX
;
2213 else if (code
== NE
)
2215 /* if ((x & C) == 0) x ^= C; is transformed to x |= C. */
2216 result
= gen_int_mode ((HOST_WIDE_INT
) 1 << bitnum
, mode
);
2217 result
= simplify_gen_binary (IOR
, mode
, x
, result
);
2221 /* if ((x & C) != 0) x ^= C; is transformed to x &= ~C. */
2222 result
= gen_int_mode (~((HOST_WIDE_INT
) 1 << bitnum
), mode
);
2223 result
= simplify_gen_binary (AND
, mode
, x
, result
);
2226 else if (GET_CODE (a
) == AND
)
2228 /* Check for "if (X & C) x &= ~C". */
2229 if (! rtx_equal_p (x
, XEXP (a
, 0))
2230 || !CONST_INT_P (XEXP (a
, 1))
2231 || (INTVAL (XEXP (a
, 1)) & GET_MODE_MASK (mode
))
2232 != (~((HOST_WIDE_INT
) 1 << bitnum
) & GET_MODE_MASK (mode
)))
2235 /* if ((x & C) == 0) x &= ~C; is transformed to nothing. */
2236 /* if ((x & C) != 0) x &= ~C; is transformed to x &= ~C. */
2237 result
= (code
== EQ
) ? a
: NULL_RTX
;
2245 noce_emit_move_insn (x
, result
);
2246 seq
= end_ifcvt_sequence (if_info
);
2250 emit_insn_before_setloc (seq
, if_info
->jump
,
2251 INSN_LOCATOR (if_info
->insn_a
));
2257 /* Similar to get_condition, only the resulting condition must be
2258 valid at JUMP, instead of at EARLIEST.
2260 If THEN_ELSE_REVERSED is true, the fallthrough does not go to the
2261 THEN block of the caller, and we have to reverse the condition. */
2264 noce_get_condition (rtx jump
, rtx
*earliest
, bool then_else_reversed
)
2269 if (! any_condjump_p (jump
))
2272 set
= pc_set (jump
);
2274 /* If this branches to JUMP_LABEL when the condition is false,
2275 reverse the condition. */
2276 reverse
= (GET_CODE (XEXP (SET_SRC (set
), 2)) == LABEL_REF
2277 && XEXP (XEXP (SET_SRC (set
), 2), 0) == JUMP_LABEL (jump
));
2279 /* We may have to reverse because the caller's if block is not canonical,
2280 i.e. the THEN block isn't the fallthrough block for the TEST block
2281 (see find_if_header). */
2282 if (then_else_reversed
)
2285 /* If the condition variable is a register and is MODE_INT, accept it. */
2287 cond
= XEXP (SET_SRC (set
), 0);
2288 tmp
= XEXP (cond
, 0);
2289 if (REG_P (tmp
) && GET_MODE_CLASS (GET_MODE (tmp
)) == MODE_INT
)
2294 cond
= gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond
)),
2295 GET_MODE (cond
), tmp
, XEXP (cond
, 1));
2299 /* Otherwise, fall back on canonicalize_condition to do the dirty
2300 work of manipulating MODE_CC values and COMPARE rtx codes. */
2301 tmp
= canonicalize_condition (jump
, cond
, reverse
, earliest
,
2302 NULL_RTX
, false, true);
2304 /* We don't handle side-effects in the condition, like handling
2305 REG_INC notes and making sure no duplicate conditions are emitted. */
2306 if (tmp
!= NULL_RTX
&& side_effects_p (tmp
))
2312 /* Return true if OP is ok for if-then-else processing. */
2315 noce_operand_ok (const_rtx op
)
2317 /* We special-case memories, so handle any of them with
2318 no address side effects. */
2320 return ! side_effects_p (XEXP (op
, 0));
2322 if (side_effects_p (op
))
2325 return ! may_trap_p (op
);
2328 /* Return true if a write into MEM may trap or fault. */
2331 noce_mem_write_may_trap_or_fault_p (const_rtx mem
)
2335 if (MEM_READONLY_P (mem
))
2338 if (may_trap_or_fault_p (mem
))
2341 addr
= XEXP (mem
, 0);
2343 /* Call target hook to avoid the effects of -fpic etc.... */
2344 addr
= targetm
.delegitimize_address (addr
);
2347 switch (GET_CODE (addr
))
2355 addr
= XEXP (addr
, 0);
2359 addr
= XEXP (addr
, 1);
2362 if (CONST_INT_P (XEXP (addr
, 1)))
2363 addr
= XEXP (addr
, 0);
2370 if (SYMBOL_REF_DECL (addr
)
2371 && decl_readonly_section (SYMBOL_REF_DECL (addr
), 0))
2381 /* Return whether we can use store speculation for MEM. TOP_BB is the
2382 basic block above the conditional block where we are considering
2383 doing the speculative store. We look for whether MEM is set
2384 unconditionally later in the function. */
2387 noce_can_store_speculate_p (basic_block top_bb
, const_rtx mem
)
2389 basic_block dominator
;
2391 for (dominator
= get_immediate_dominator (CDI_POST_DOMINATORS
, top_bb
);
2393 dominator
= get_immediate_dominator (CDI_POST_DOMINATORS
, dominator
))
2397 FOR_BB_INSNS (dominator
, insn
)
2399 /* If we see something that might be a memory barrier, we
2400 have to stop looking. Even if the MEM is set later in
2401 the function, we still don't want to set it
2402 unconditionally before the barrier. */
2404 && (volatile_insn_p (PATTERN (insn
))
2405 || (CALL_P (insn
) && (!RTL_CONST_CALL_P (insn
)))))
2408 if (memory_modified_in_insn_p (mem
, insn
))
2410 if (modified_in_p (XEXP (mem
, 0), insn
))
2419 /* Given a simple IF-THEN-JOIN or IF-THEN-ELSE-JOIN block, attempt to convert
2420 it without using conditional execution. Return TRUE if we were successful
2421 at converting the block. */
2424 noce_process_if_block (struct noce_if_info
*if_info
)
2426 basic_block test_bb
= if_info
->test_bb
; /* test block */
2427 basic_block then_bb
= if_info
->then_bb
; /* THEN */
2428 basic_block else_bb
= if_info
->else_bb
; /* ELSE or NULL */
2429 basic_block join_bb
= if_info
->join_bb
; /* JOIN */
2430 rtx jump
= if_info
->jump
;
2431 rtx cond
= if_info
->cond
;
2434 rtx orig_x
, x
, a
, b
;
2436 /* We're looking for patterns of the form
2438 (1) if (...) x = a; else x = b;
2439 (2) x = b; if (...) x = a;
2440 (3) if (...) x = a; // as if with an initial x = x.
2442 The later patterns require jumps to be more expensive.
2444 ??? For future expansion, look for multiple X in such patterns. */
2446 /* Look for one of the potential sets. */
2447 insn_a
= first_active_insn (then_bb
);
2449 || insn_a
!= last_active_insn (then_bb
, FALSE
)
2450 || (set_a
= single_set (insn_a
)) == NULL_RTX
)
2453 x
= SET_DEST (set_a
);
2454 a
= SET_SRC (set_a
);
2456 /* Look for the other potential set. Make sure we've got equivalent
2458 /* ??? This is overconservative. Storing to two different mems is
2459 as easy as conditionally computing the address. Storing to a
2460 single mem merely requires a scratch memory to use as one of the
2461 destination addresses; often the memory immediately below the
2462 stack pointer is available for this. */
2466 insn_b
= first_active_insn (else_bb
);
2468 || insn_b
!= last_active_insn (else_bb
, FALSE
)
2469 || (set_b
= single_set (insn_b
)) == NULL_RTX
2470 || ! rtx_equal_p (x
, SET_DEST (set_b
)))
2475 insn_b
= prev_nonnote_nondebug_insn (if_info
->cond_earliest
);
2476 /* We're going to be moving the evaluation of B down from above
2477 COND_EARLIEST to JUMP. Make sure the relevant data is still
2480 || BLOCK_FOR_INSN (insn_b
) != BLOCK_FOR_INSN (if_info
->cond_earliest
)
2481 || !NONJUMP_INSN_P (insn_b
)
2482 || (set_b
= single_set (insn_b
)) == NULL_RTX
2483 || ! rtx_equal_p (x
, SET_DEST (set_b
))
2484 || ! noce_operand_ok (SET_SRC (set_b
))
2485 || reg_overlap_mentioned_p (x
, SET_SRC (set_b
))
2486 || modified_between_p (SET_SRC (set_b
), insn_b
, jump
)
2487 /* Likewise with X. In particular this can happen when
2488 noce_get_condition looks farther back in the instruction
2489 stream than one might expect. */
2490 || reg_overlap_mentioned_p (x
, cond
)
2491 || reg_overlap_mentioned_p (x
, a
)
2492 || modified_between_p (x
, insn_b
, jump
))
2493 insn_b
= set_b
= NULL_RTX
;
2496 /* If x has side effects then only the if-then-else form is safe to
2497 convert. But even in that case we would need to restore any notes
2498 (such as REG_INC) at then end. That can be tricky if
2499 noce_emit_move_insn expands to more than one insn, so disable the
2500 optimization entirely for now if there are side effects. */
2501 if (side_effects_p (x
))
2504 b
= (set_b
? SET_SRC (set_b
) : x
);
2506 /* Only operate on register destinations, and even then avoid extending
2507 the lifetime of hard registers on small register class machines. */
2510 || (HARD_REGISTER_P (x
)
2511 && targetm
.small_register_classes_for_mode_p (GET_MODE (x
))))
2513 if (GET_MODE (x
) == BLKmode
)
2516 if (GET_CODE (x
) == ZERO_EXTRACT
2517 && (!CONST_INT_P (XEXP (x
, 1))
2518 || !CONST_INT_P (XEXP (x
, 2))))
2521 x
= gen_reg_rtx (GET_MODE (GET_CODE (x
) == STRICT_LOW_PART
2522 ? XEXP (x
, 0) : x
));
2525 /* Don't operate on sources that may trap or are volatile. */
2526 if (! noce_operand_ok (a
) || ! noce_operand_ok (b
))
2530 /* Set up the info block for our subroutines. */
2531 if_info
->insn_a
= insn_a
;
2532 if_info
->insn_b
= insn_b
;
2537 /* Try optimizations in some approximation of a useful order. */
2538 /* ??? Should first look to see if X is live incoming at all. If it
2539 isn't, we don't need anything but an unconditional set. */
2541 /* Look and see if A and B are really the same. Avoid creating silly
2542 cmove constructs that no one will fix up later. */
2543 if (rtx_equal_p (a
, b
))
2545 /* If we have an INSN_B, we don't have to create any new rtl. Just
2546 move the instruction that we already have. If we don't have an
2547 INSN_B, that means that A == X, and we've got a noop move. In
2548 that case don't do anything and let the code below delete INSN_A. */
2549 if (insn_b
&& else_bb
)
2553 if (else_bb
&& insn_b
== BB_END (else_bb
))
2554 BB_END (else_bb
) = PREV_INSN (insn_b
);
2555 reorder_insns (insn_b
, insn_b
, PREV_INSN (jump
));
2557 /* If there was a REG_EQUAL note, delete it since it may have been
2558 true due to this insn being after a jump. */
2559 if ((note
= find_reg_note (insn_b
, REG_EQUAL
, NULL_RTX
)) != 0)
2560 remove_note (insn_b
, note
);
2564 /* If we have "x = b; if (...) x = a;", and x has side-effects, then
2565 x must be executed twice. */
2566 else if (insn_b
&& side_effects_p (orig_x
))
2573 if (!set_b
&& MEM_P (orig_x
))
2575 /* Disallow the "if (...) x = a;" form (implicit "else x = x;")
2576 for optimizations if writing to x may trap or fault,
2577 i.e. it's a memory other than a static var or a stack slot,
2578 is misaligned on strict aligned machines or is read-only. If
2579 x is a read-only memory, then the program is valid only if we
2580 avoid the store into it. If there are stores on both the
2581 THEN and ELSE arms, then we can go ahead with the conversion;
2582 either the program is broken, or the condition is always
2583 false such that the other memory is selected. */
2584 if (noce_mem_write_may_trap_or_fault_p (orig_x
))
2587 /* Avoid store speculation: given "if (...) x = a" where x is a
2588 MEM, we only want to do the store if x is always set
2589 somewhere in the function. This avoids cases like
2590 if (pthread_mutex_trylock(mutex))
2592 where we only want global_variable to be changed if the mutex
2593 is held. FIXME: This should ideally be expressed directly in
2595 if (!noce_can_store_speculate_p (test_bb
, orig_x
))
2599 if (noce_try_move (if_info
))
2601 if (noce_try_store_flag (if_info
))
2603 if (noce_try_bitop (if_info
))
2605 if (noce_try_minmax (if_info
))
2607 if (noce_try_abs (if_info
))
2609 if (HAVE_conditional_move
2610 && noce_try_cmove (if_info
))
2612 if (! targetm
.have_conditional_execution ())
2614 if (noce_try_store_flag_constants (if_info
))
2616 if (noce_try_addcc (if_info
))
2618 if (noce_try_store_flag_mask (if_info
))
2620 if (HAVE_conditional_move
2621 && noce_try_cmove_arith (if_info
))
2623 if (noce_try_sign_mask (if_info
))
2627 if (!else_bb
&& set_b
)
2629 insn_b
= set_b
= NULL_RTX
;
2638 /* If we used a temporary, fix it up now. */
2644 noce_emit_move_insn (orig_x
, x
);
2646 set_used_flags (orig_x
);
2647 unshare_all_rtl_in_chain (seq
);
2650 emit_insn_before_setloc (seq
, BB_END (test_bb
), INSN_LOCATOR (insn_a
));
2653 /* The original THEN and ELSE blocks may now be removed. The test block
2654 must now jump to the join block. If the test block and the join block
2655 can be merged, do so. */
2658 delete_basic_block (else_bb
);
2662 remove_edge (find_edge (test_bb
, join_bb
));
2664 remove_edge (find_edge (then_bb
, join_bb
));
2665 redirect_edge_and_branch_force (single_succ_edge (test_bb
), join_bb
);
2666 delete_basic_block (then_bb
);
2669 if (can_merge_blocks_p (test_bb
, join_bb
))
2671 merge_blocks (test_bb
, join_bb
);
2675 num_updated_if_blocks
++;
2679 /* Check whether a block is suitable for conditional move conversion.
2680 Every insn must be a simple set of a register to a constant or a
2681 register. For each assignment, store the value in the array VALS,
2682 indexed by register number, then store the register number in
2683 REGS. COND is the condition we will test. */
2686 check_cond_move_block (basic_block bb
, rtx
*vals
, VEC (int, heap
) **regs
,
2691 /* We can only handle simple jumps at the end of the basic block.
2692 It is almost impossible to update the CFG otherwise. */
2694 if (JUMP_P (insn
) && !onlyjump_p (insn
))
2697 FOR_BB_INSNS (bb
, insn
)
2701 if (!NONDEBUG_INSN_P (insn
) || JUMP_P (insn
))
2703 set
= single_set (insn
);
2707 dest
= SET_DEST (set
);
2708 src
= SET_SRC (set
);
2710 || (HARD_REGISTER_P (dest
)
2711 && targetm
.small_register_classes_for_mode_p (GET_MODE (dest
))))
2714 if (!CONSTANT_P (src
) && !register_operand (src
, VOIDmode
))
2717 if (side_effects_p (src
) || side_effects_p (dest
))
2720 if (may_trap_p (src
) || may_trap_p (dest
))
2723 /* Don't try to handle this if the source register was
2724 modified earlier in the block. */
2726 && vals
[REGNO (src
)] != NULL
)
2727 || (GET_CODE (src
) == SUBREG
&& REG_P (SUBREG_REG (src
))
2728 && vals
[REGNO (SUBREG_REG (src
))] != NULL
))
2731 /* Don't try to handle this if the destination register was
2732 modified earlier in the block. */
2733 if (vals
[REGNO (dest
)] != NULL
)
2736 /* Don't try to handle this if the condition uses the
2737 destination register. */
2738 if (reg_overlap_mentioned_p (dest
, cond
))
2741 /* Don't try to handle this if the source register is modified
2742 later in the block. */
2743 if (!CONSTANT_P (src
)
2744 && modified_between_p (src
, insn
, NEXT_INSN (BB_END (bb
))))
2747 vals
[REGNO (dest
)] = src
;
2749 VEC_safe_push (int, heap
, *regs
, REGNO (dest
));
2755 /* Given a basic block BB suitable for conditional move conversion,
2756 a condition COND, and arrays THEN_VALS and ELSE_VALS containing the
2757 register values depending on COND, emit the insns in the block as
2758 conditional moves. If ELSE_BLOCK is true, THEN_BB was already
2759 processed. The caller has started a sequence for the conversion.
2760 Return true if successful, false if something goes wrong. */
2763 cond_move_convert_if_block (struct noce_if_info
*if_infop
,
2764 basic_block bb
, rtx cond
,
2765 rtx
*then_vals
, rtx
*else_vals
,
2769 rtx insn
, cond_arg0
, cond_arg1
;
2771 code
= GET_CODE (cond
);
2772 cond_arg0
= XEXP (cond
, 0);
2773 cond_arg1
= XEXP (cond
, 1);
2775 FOR_BB_INSNS (bb
, insn
)
2777 rtx set
, target
, dest
, t
, e
;
2780 /* ??? Maybe emit conditional debug insn? */
2781 if (!NONDEBUG_INSN_P (insn
) || JUMP_P (insn
))
2783 set
= single_set (insn
);
2784 gcc_assert (set
&& REG_P (SET_DEST (set
)));
2786 dest
= SET_DEST (set
);
2787 regno
= REGNO (dest
);
2789 t
= then_vals
[regno
];
2790 e
= else_vals
[regno
];
2794 /* If this register was set in the then block, we already
2795 handled this case there. */
2808 target
= noce_emit_cmove (if_infop
, dest
, code
, cond_arg0
, cond_arg1
,
2814 noce_emit_move_insn (dest
, target
);
2820 /* Given a simple IF-THEN-JOIN or IF-THEN-ELSE-JOIN block, attempt to convert
2821 it using only conditional moves. Return TRUE if we were successful at
2822 converting the block. */
2825 cond_move_process_if_block (struct noce_if_info
*if_info
)
2827 basic_block test_bb
= if_info
->test_bb
;
2828 basic_block then_bb
= if_info
->then_bb
;
2829 basic_block else_bb
= if_info
->else_bb
;
2830 basic_block join_bb
= if_info
->join_bb
;
2831 rtx jump
= if_info
->jump
;
2832 rtx cond
= if_info
->cond
;
2834 int max_reg
, size
, c
, reg
;
2837 VEC (int, heap
) *then_regs
= NULL
;
2838 VEC (int, heap
) *else_regs
= NULL
;
2841 /* Build a mapping for each block to the value used for each
2843 max_reg
= max_reg_num ();
2844 size
= (max_reg
+ 1) * sizeof (rtx
);
2845 then_vals
= (rtx
*) alloca (size
);
2846 else_vals
= (rtx
*) alloca (size
);
2847 memset (then_vals
, 0, size
);
2848 memset (else_vals
, 0, size
);
2850 /* Make sure the blocks are suitable. */
2851 if (!check_cond_move_block (then_bb
, then_vals
, &then_regs
, cond
)
2853 && !check_cond_move_block (else_bb
, else_vals
, &else_regs
, cond
)))
2855 VEC_free (int, heap
, then_regs
);
2856 VEC_free (int, heap
, else_regs
);
2860 /* Make sure the blocks can be used together. If the same register
2861 is set in both blocks, and is not set to a constant in both
2862 cases, then both blocks must set it to the same register. We
2863 have already verified that if it is set to a register, that the
2864 source register does not change after the assignment. Also count
2865 the number of registers set in only one of the blocks. */
2867 FOR_EACH_VEC_ELT (int, then_regs
, i
, reg
)
2869 if (!then_vals
[reg
] && !else_vals
[reg
])
2872 if (!else_vals
[reg
])
2876 if (!CONSTANT_P (then_vals
[reg
])
2877 && !CONSTANT_P (else_vals
[reg
])
2878 && !rtx_equal_p (then_vals
[reg
], else_vals
[reg
]))
2880 VEC_free (int, heap
, then_regs
);
2881 VEC_free (int, heap
, else_regs
);
2887 /* Finish off c for MAX_CONDITIONAL_EXECUTE. */
2888 FOR_EACH_VEC_ELT (int, else_regs
, i
, reg
)
2889 if (!then_vals
[reg
])
2892 /* Make sure it is reasonable to convert this block. What matters
2893 is the number of assignments currently made in only one of the
2894 branches, since if we convert we are going to always execute
2896 if (c
> MAX_CONDITIONAL_EXECUTE
)
2898 VEC_free (int, heap
, then_regs
);
2899 VEC_free (int, heap
, else_regs
);
2903 /* Try to emit the conditional moves. First do the then block,
2904 then do anything left in the else blocks. */
2906 if (!cond_move_convert_if_block (if_info
, then_bb
, cond
,
2907 then_vals
, else_vals
, false)
2909 && !cond_move_convert_if_block (if_info
, else_bb
, cond
,
2910 then_vals
, else_vals
, true)))
2913 VEC_free (int, heap
, then_regs
);
2914 VEC_free (int, heap
, else_regs
);
2917 seq
= end_ifcvt_sequence (if_info
);
2920 VEC_free (int, heap
, then_regs
);
2921 VEC_free (int, heap
, else_regs
);
2925 loc_insn
= first_active_insn (then_bb
);
2928 loc_insn
= first_active_insn (else_bb
);
2929 gcc_assert (loc_insn
);
2931 emit_insn_before_setloc (seq
, jump
, INSN_LOCATOR (loc_insn
));
2935 delete_basic_block (else_bb
);
2939 remove_edge (find_edge (test_bb
, join_bb
));
2941 remove_edge (find_edge (then_bb
, join_bb
));
2942 redirect_edge_and_branch_force (single_succ_edge (test_bb
), join_bb
);
2943 delete_basic_block (then_bb
);
2946 if (can_merge_blocks_p (test_bb
, join_bb
))
2948 merge_blocks (test_bb
, join_bb
);
2952 num_updated_if_blocks
++;
2954 VEC_free (int, heap
, then_regs
);
2955 VEC_free (int, heap
, else_regs
);
2960 /* Determine if a given basic block heads a simple IF-THEN-JOIN or an
2961 IF-THEN-ELSE-JOIN block.
2963 If so, we'll try to convert the insns to not require the branch,
2964 using only transformations that do not require conditional execution.
2966 Return TRUE if we were successful at converting the block. */
2969 noce_find_if_block (basic_block test_bb
, edge then_edge
, edge else_edge
,
2972 basic_block then_bb
, else_bb
, join_bb
;
2973 bool then_else_reversed
= false;
2976 struct noce_if_info if_info
;
2978 /* We only ever should get here before reload. */
2979 gcc_assert (!reload_completed
);
2981 /* Recognize an IF-THEN-ELSE-JOIN block. */
2982 if (single_pred_p (then_edge
->dest
)
2983 && single_succ_p (then_edge
->dest
)
2984 && single_pred_p (else_edge
->dest
)
2985 && single_succ_p (else_edge
->dest
)
2986 && single_succ (then_edge
->dest
) == single_succ (else_edge
->dest
))
2988 then_bb
= then_edge
->dest
;
2989 else_bb
= else_edge
->dest
;
2990 join_bb
= single_succ (then_bb
);
2992 /* Recognize an IF-THEN-JOIN block. */
2993 else if (single_pred_p (then_edge
->dest
)
2994 && single_succ_p (then_edge
->dest
)
2995 && single_succ (then_edge
->dest
) == else_edge
->dest
)
2997 then_bb
= then_edge
->dest
;
2998 else_bb
= NULL_BLOCK
;
2999 join_bb
= else_edge
->dest
;
3001 /* Recognize an IF-ELSE-JOIN block. We can have those because the order
3002 of basic blocks in cfglayout mode does not matter, so the fallthrough
3003 edge can go to any basic block (and not just to bb->next_bb, like in
3005 else if (single_pred_p (else_edge
->dest
)
3006 && single_succ_p (else_edge
->dest
)
3007 && single_succ (else_edge
->dest
) == then_edge
->dest
)
3009 /* The noce transformations do not apply to IF-ELSE-JOIN blocks.
3010 To make this work, we have to invert the THEN and ELSE blocks
3011 and reverse the jump condition. */
3012 then_bb
= else_edge
->dest
;
3013 else_bb
= NULL_BLOCK
;
3014 join_bb
= single_succ (then_bb
);
3015 then_else_reversed
= true;
3018 /* Not a form we can handle. */
3021 /* The edges of the THEN and ELSE blocks cannot have complex edges. */
3022 if (single_succ_edge (then_bb
)->flags
& EDGE_COMPLEX
)
3025 && single_succ_edge (else_bb
)->flags
& EDGE_COMPLEX
)
3028 num_possible_if_blocks
++;
3033 "\nIF-THEN%s-JOIN block found, pass %d, test %d, then %d",
3034 (else_bb
) ? "-ELSE" : "",
3035 pass
, test_bb
->index
, then_bb
->index
);
3038 fprintf (dump_file
, ", else %d", else_bb
->index
);
3040 fprintf (dump_file
, ", join %d\n", join_bb
->index
);
3043 /* If the conditional jump is more than just a conditional
3044 jump, then we can not do if-conversion on this block. */
3045 jump
= BB_END (test_bb
);
3046 if (! onlyjump_p (jump
))
3049 /* If this is not a standard conditional jump, we can't parse it. */
3050 cond
= noce_get_condition (jump
, &cond_earliest
, then_else_reversed
);
3054 /* We must be comparing objects whose modes imply the size. */
3055 if (GET_MODE (XEXP (cond
, 0)) == BLKmode
)
3058 /* Initialize an IF_INFO struct to pass around. */
3059 memset (&if_info
, 0, sizeof if_info
);
3060 if_info
.test_bb
= test_bb
;
3061 if_info
.then_bb
= then_bb
;
3062 if_info
.else_bb
= else_bb
;
3063 if_info
.join_bb
= join_bb
;
3064 if_info
.cond
= cond
;
3065 if_info
.cond_earliest
= cond_earliest
;
3066 if_info
.jump
= jump
;
3067 if_info
.then_else_reversed
= then_else_reversed
;
3068 if_info
.branch_cost
= BRANCH_COST (optimize_bb_for_speed_p (test_bb
),
3069 predictable_edge_p (then_edge
));
3071 /* Do the real work. */
3073 if (noce_process_if_block (&if_info
))
3076 if (HAVE_conditional_move
3077 && cond_move_process_if_block (&if_info
))
3084 /* Merge the blocks and mark for local life update. */
3087 merge_if_block (struct ce_if_block
* ce_info
)
3089 basic_block test_bb
= ce_info
->test_bb
; /* last test block */
3090 basic_block then_bb
= ce_info
->then_bb
; /* THEN */
3091 basic_block else_bb
= ce_info
->else_bb
; /* ELSE or NULL */
3092 basic_block join_bb
= ce_info
->join_bb
; /* join block */
3093 basic_block combo_bb
;
3095 /* All block merging is done into the lower block numbers. */
3098 df_set_bb_dirty (test_bb
);
3100 /* Merge any basic blocks to handle && and || subtests. Each of
3101 the blocks are on the fallthru path from the predecessor block. */
3102 if (ce_info
->num_multiple_test_blocks
> 0)
3104 basic_block bb
= test_bb
;
3105 basic_block last_test_bb
= ce_info
->last_test_bb
;
3106 basic_block fallthru
= block_fallthru (bb
);
3111 fallthru
= block_fallthru (bb
);
3112 merge_blocks (combo_bb
, bb
);
3115 while (bb
!= last_test_bb
);
3118 /* Merge TEST block into THEN block. Normally the THEN block won't have a
3119 label, but it might if there were || tests. That label's count should be
3120 zero, and it normally should be removed. */
3124 merge_blocks (combo_bb
, then_bb
);
3128 /* The ELSE block, if it existed, had a label. That label count
3129 will almost always be zero, but odd things can happen when labels
3130 get their addresses taken. */
3133 merge_blocks (combo_bb
, else_bb
);
3137 /* If there was no join block reported, that means it was not adjacent
3138 to the others, and so we cannot merge them. */
3142 rtx last
= BB_END (combo_bb
);
3144 /* The outgoing edge for the current COMBO block should already
3145 be correct. Verify this. */
3146 if (EDGE_COUNT (combo_bb
->succs
) == 0)
3147 gcc_assert (find_reg_note (last
, REG_NORETURN
, NULL
)
3148 || (NONJUMP_INSN_P (last
)
3149 && GET_CODE (PATTERN (last
)) == TRAP_IF
3150 && (TRAP_CONDITION (PATTERN (last
))
3151 == const_true_rtx
)));
3154 /* There should still be something at the end of the THEN or ELSE
3155 blocks taking us to our final destination. */
3156 gcc_assert (JUMP_P (last
)
3157 || (EDGE_SUCC (combo_bb
, 0)->dest
== EXIT_BLOCK_PTR
3159 && SIBLING_CALL_P (last
))
3160 || ((EDGE_SUCC (combo_bb
, 0)->flags
& EDGE_EH
)
3161 && can_throw_internal (last
)));
3164 /* The JOIN block may have had quite a number of other predecessors too.
3165 Since we've already merged the TEST, THEN and ELSE blocks, we should
3166 have only one remaining edge from our if-then-else diamond. If there
3167 is more than one remaining edge, it must come from elsewhere. There
3168 may be zero incoming edges if the THEN block didn't actually join
3169 back up (as with a call to a non-return function). */
3170 else if (EDGE_COUNT (join_bb
->preds
) < 2
3171 && join_bb
!= EXIT_BLOCK_PTR
)
3173 /* We can merge the JOIN cleanly and update the dataflow try
3174 again on this pass.*/
3175 merge_blocks (combo_bb
, join_bb
);
3180 /* We cannot merge the JOIN. */
3182 /* The outgoing edge for the current COMBO block should already
3183 be correct. Verify this. */
3184 gcc_assert (single_succ_p (combo_bb
)
3185 && single_succ (combo_bb
) == join_bb
);
3187 /* Remove the jump and cruft from the end of the COMBO block. */
3188 if (join_bb
!= EXIT_BLOCK_PTR
)
3189 tidy_fallthru_edge (single_succ_edge (combo_bb
));
3192 num_updated_if_blocks
++;
3195 /* Find a block ending in a simple IF condition and try to transform it
3196 in some way. When converting a multi-block condition, put the new code
3197 in the first such block and delete the rest. Return a pointer to this
3198 first block if some transformation was done. Return NULL otherwise. */
3201 find_if_header (basic_block test_bb
, int pass
)
3203 ce_if_block_t ce_info
;
3207 /* The kind of block we're looking for has exactly two successors. */
3208 if (EDGE_COUNT (test_bb
->succs
) != 2)
3211 then_edge
= EDGE_SUCC (test_bb
, 0);
3212 else_edge
= EDGE_SUCC (test_bb
, 1);
3214 if (df_get_bb_dirty (then_edge
->dest
))
3216 if (df_get_bb_dirty (else_edge
->dest
))
3219 /* Neither edge should be abnormal. */
3220 if ((then_edge
->flags
& EDGE_COMPLEX
)
3221 || (else_edge
->flags
& EDGE_COMPLEX
))
3224 /* Nor exit the loop. */
3225 if ((then_edge
->flags
& EDGE_LOOP_EXIT
)
3226 || (else_edge
->flags
& EDGE_LOOP_EXIT
))
3229 /* The THEN edge is canonically the one that falls through. */
3230 if (then_edge
->flags
& EDGE_FALLTHRU
)
3232 else if (else_edge
->flags
& EDGE_FALLTHRU
)
3235 else_edge
= then_edge
;
3239 /* Otherwise this must be a multiway branch of some sort. */
3242 memset (&ce_info
, 0, sizeof (ce_info
));
3243 ce_info
.test_bb
= test_bb
;
3244 ce_info
.then_bb
= then_edge
->dest
;
3245 ce_info
.else_bb
= else_edge
->dest
;
3246 ce_info
.pass
= pass
;
3248 #ifdef IFCVT_INIT_EXTRA_FIELDS
3249 IFCVT_INIT_EXTRA_FIELDS (&ce_info
);
3252 if (!reload_completed
3253 && noce_find_if_block (test_bb
, then_edge
, else_edge
, pass
))
3256 if (reload_completed
3257 && targetm
.have_conditional_execution ()
3258 && cond_exec_find_if_block (&ce_info
))
3262 && optab_handler (ctrap_optab
, word_mode
) != CODE_FOR_nothing
3263 && find_cond_trap (test_bb
, then_edge
, else_edge
))
3266 if (dom_info_state (CDI_POST_DOMINATORS
) >= DOM_NO_FAST_QUERY
3267 && (reload_completed
|| !targetm
.have_conditional_execution ()))
3269 if (find_if_case_1 (test_bb
, then_edge
, else_edge
))
3271 if (find_if_case_2 (test_bb
, then_edge
, else_edge
))
3279 fprintf (dump_file
, "Conversion succeeded on pass %d.\n", pass
);
3280 /* Set this so we continue looking. */
3281 cond_exec_changed_p
= TRUE
;
3282 return ce_info
.test_bb
;
3285 /* Return true if a block has two edges, one of which falls through to the next
3286 block, and the other jumps to a specific block, so that we can tell if the
3287 block is part of an && test or an || test. Returns either -1 or the number
3288 of non-note, non-jump, non-USE/CLOBBER insns in the block. */
3291 block_jumps_and_fallthru_p (basic_block cur_bb
, basic_block target_bb
)
3294 int fallthru_p
= FALSE
;
3301 if (!cur_bb
|| !target_bb
)
3304 /* If no edges, obviously it doesn't jump or fallthru. */
3305 if (EDGE_COUNT (cur_bb
->succs
) == 0)
3308 FOR_EACH_EDGE (cur_edge
, ei
, cur_bb
->succs
)
3310 if (cur_edge
->flags
& EDGE_COMPLEX
)
3311 /* Anything complex isn't what we want. */
3314 else if (cur_edge
->flags
& EDGE_FALLTHRU
)
3317 else if (cur_edge
->dest
== target_bb
)
3324 if ((jump_p
& fallthru_p
) == 0)
3327 /* Don't allow calls in the block, since this is used to group && and ||
3328 together for conditional execution support. ??? we should support
3329 conditional execution support across calls for IA-64 some day, but
3330 for now it makes the code simpler. */
3331 end
= BB_END (cur_bb
);
3332 insn
= BB_HEAD (cur_bb
);
3334 while (insn
!= NULL_RTX
)
3341 && !DEBUG_INSN_P (insn
)
3342 && GET_CODE (PATTERN (insn
)) != USE
3343 && GET_CODE (PATTERN (insn
)) != CLOBBER
)
3349 insn
= NEXT_INSN (insn
);
3355 /* Determine if a given basic block heads a simple IF-THEN or IF-THEN-ELSE
3356 block. If so, we'll try to convert the insns to not require the branch.
3357 Return TRUE if we were successful at converting the block. */
3360 cond_exec_find_if_block (struct ce_if_block
* ce_info
)
3362 basic_block test_bb
= ce_info
->test_bb
;
3363 basic_block then_bb
= ce_info
->then_bb
;
3364 basic_block else_bb
= ce_info
->else_bb
;
3365 basic_block join_bb
= NULL_BLOCK
;
3370 ce_info
->last_test_bb
= test_bb
;
3372 /* We only ever should get here after reload,
3373 and if we have conditional execution. */
3374 gcc_assert (reload_completed
&& targetm
.have_conditional_execution ());
3376 /* Discover if any fall through predecessors of the current test basic block
3377 were && tests (which jump to the else block) or || tests (which jump to
3379 if (single_pred_p (test_bb
)
3380 && single_pred_edge (test_bb
)->flags
== EDGE_FALLTHRU
)
3382 basic_block bb
= single_pred (test_bb
);
3383 basic_block target_bb
;
3384 int max_insns
= MAX_CONDITIONAL_EXECUTE
;
3387 /* Determine if the preceding block is an && or || block. */
3388 if ((n_insns
= block_jumps_and_fallthru_p (bb
, else_bb
)) >= 0)
3390 ce_info
->and_and_p
= TRUE
;
3391 target_bb
= else_bb
;
3393 else if ((n_insns
= block_jumps_and_fallthru_p (bb
, then_bb
)) >= 0)
3395 ce_info
->and_and_p
= FALSE
;
3396 target_bb
= then_bb
;
3399 target_bb
= NULL_BLOCK
;
3401 if (target_bb
&& n_insns
<= max_insns
)
3403 int total_insns
= 0;
3406 ce_info
->last_test_bb
= test_bb
;
3408 /* Found at least one && or || block, look for more. */
3411 ce_info
->test_bb
= test_bb
= bb
;
3412 total_insns
+= n_insns
;
3415 if (!single_pred_p (bb
))
3418 bb
= single_pred (bb
);
3419 n_insns
= block_jumps_and_fallthru_p (bb
, target_bb
);
3421 while (n_insns
>= 0 && (total_insns
+ n_insns
) <= max_insns
);
3423 ce_info
->num_multiple_test_blocks
= blocks
;
3424 ce_info
->num_multiple_test_insns
= total_insns
;
3426 if (ce_info
->and_and_p
)
3427 ce_info
->num_and_and_blocks
= blocks
;
3429 ce_info
->num_or_or_blocks
= blocks
;
3433 /* The THEN block of an IF-THEN combo must have exactly one predecessor,
3434 other than any || blocks which jump to the THEN block. */
3435 if ((EDGE_COUNT (then_bb
->preds
) - ce_info
->num_or_or_blocks
) != 1)
3438 /* The edges of the THEN and ELSE blocks cannot have complex edges. */
3439 FOR_EACH_EDGE (cur_edge
, ei
, then_bb
->preds
)
3441 if (cur_edge
->flags
& EDGE_COMPLEX
)
3445 FOR_EACH_EDGE (cur_edge
, ei
, else_bb
->preds
)
3447 if (cur_edge
->flags
& EDGE_COMPLEX
)
3451 /* The THEN block of an IF-THEN combo must have zero or one successors. */
3452 if (EDGE_COUNT (then_bb
->succs
) > 0
3453 && (!single_succ_p (then_bb
)
3454 || (single_succ_edge (then_bb
)->flags
& EDGE_COMPLEX
)
3455 || (epilogue_completed
3456 && tablejump_p (BB_END (then_bb
), NULL
, NULL
))))
3459 /* If the THEN block has no successors, conditional execution can still
3460 make a conditional call. Don't do this unless the ELSE block has
3461 only one incoming edge -- the CFG manipulation is too ugly otherwise.
3462 Check for the last insn of the THEN block being an indirect jump, which
3463 is listed as not having any successors, but confuses the rest of the CE
3464 code processing. ??? we should fix this in the future. */
3465 if (EDGE_COUNT (then_bb
->succs
) == 0)
3467 if (single_pred_p (else_bb
))
3469 rtx last_insn
= BB_END (then_bb
);
3472 && NOTE_P (last_insn
)
3473 && last_insn
!= BB_HEAD (then_bb
))
3474 last_insn
= PREV_INSN (last_insn
);
3477 && JUMP_P (last_insn
)
3478 && ! simplejump_p (last_insn
))
3482 else_bb
= NULL_BLOCK
;
3488 /* If the THEN block's successor is the other edge out of the TEST block,
3489 then we have an IF-THEN combo without an ELSE. */
3490 else if (single_succ (then_bb
) == else_bb
)
3493 else_bb
= NULL_BLOCK
;
3496 /* If the THEN and ELSE block meet in a subsequent block, and the ELSE
3497 has exactly one predecessor and one successor, and the outgoing edge
3498 is not complex, then we have an IF-THEN-ELSE combo. */
3499 else if (single_succ_p (else_bb
)
3500 && single_succ (then_bb
) == single_succ (else_bb
)
3501 && single_pred_p (else_bb
)
3502 && !(single_succ_edge (else_bb
)->flags
& EDGE_COMPLEX
)
3503 && !(epilogue_completed
3504 && tablejump_p (BB_END (else_bb
), NULL
, NULL
)))
3505 join_bb
= single_succ (else_bb
);
3507 /* Otherwise it is not an IF-THEN or IF-THEN-ELSE combination. */
3511 num_possible_if_blocks
++;
3516 "\nIF-THEN%s block found, pass %d, start block %d "
3517 "[insn %d], then %d [%d]",
3518 (else_bb
) ? "-ELSE" : "",
3521 BB_HEAD (test_bb
) ? (int)INSN_UID (BB_HEAD (test_bb
)) : -1,
3523 BB_HEAD (then_bb
) ? (int)INSN_UID (BB_HEAD (then_bb
)) : -1);
3526 fprintf (dump_file
, ", else %d [%d]",
3528 BB_HEAD (else_bb
) ? (int)INSN_UID (BB_HEAD (else_bb
)) : -1);
3530 fprintf (dump_file
, ", join %d [%d]",
3532 BB_HEAD (join_bb
) ? (int)INSN_UID (BB_HEAD (join_bb
)) : -1);
3534 if (ce_info
->num_multiple_test_blocks
> 0)
3535 fprintf (dump_file
, ", %d %s block%s last test %d [%d]",
3536 ce_info
->num_multiple_test_blocks
,
3537 (ce_info
->and_and_p
) ? "&&" : "||",
3538 (ce_info
->num_multiple_test_blocks
== 1) ? "" : "s",
3539 ce_info
->last_test_bb
->index
,
3540 ((BB_HEAD (ce_info
->last_test_bb
))
3541 ? (int)INSN_UID (BB_HEAD (ce_info
->last_test_bb
))
3544 fputc ('\n', dump_file
);
3547 /* Make sure IF, THEN, and ELSE, blocks are adjacent. Actually, we get the
3548 first condition for free, since we've already asserted that there's a
3549 fallthru edge from IF to THEN. Likewise for the && and || blocks, since
3550 we checked the FALLTHRU flag, those are already adjacent to the last IF
3552 /* ??? As an enhancement, move the ELSE block. Have to deal with
3553 BLOCK notes, if by no other means than backing out the merge if they
3554 exist. Sticky enough I don't want to think about it now. */
3556 if (else_bb
&& (next
= next
->next_bb
) != else_bb
)
3558 if ((next
= next
->next_bb
) != join_bb
&& join_bb
!= EXIT_BLOCK_PTR
)
3566 /* Do the real work. */
3568 ce_info
->else_bb
= else_bb
;
3569 ce_info
->join_bb
= join_bb
;
3571 /* If we have && and || tests, try to first handle combining the && and ||
3572 tests into the conditional code, and if that fails, go back and handle
3573 it without the && and ||, which at present handles the && case if there
3574 was no ELSE block. */
3575 if (cond_exec_process_if_block (ce_info
, TRUE
))
3578 if (ce_info
->num_multiple_test_blocks
)
3582 if (cond_exec_process_if_block (ce_info
, FALSE
))
3589 /* Convert a branch over a trap, or a branch
3590 to a trap, into a conditional trap. */
3593 find_cond_trap (basic_block test_bb
, edge then_edge
, edge else_edge
)
3595 basic_block then_bb
= then_edge
->dest
;
3596 basic_block else_bb
= else_edge
->dest
;
3597 basic_block other_bb
, trap_bb
;
3598 rtx trap
, jump
, cond
, cond_earliest
, seq
;
3601 /* Locate the block with the trap instruction. */
3602 /* ??? While we look for no successors, we really ought to allow
3603 EH successors. Need to fix merge_if_block for that to work. */
3604 if ((trap
= block_has_only_trap (then_bb
)) != NULL
)
3605 trap_bb
= then_bb
, other_bb
= else_bb
;
3606 else if ((trap
= block_has_only_trap (else_bb
)) != NULL
)
3607 trap_bb
= else_bb
, other_bb
= then_bb
;
3613 fprintf (dump_file
, "\nTRAP-IF block found, start %d, trap %d\n",
3614 test_bb
->index
, trap_bb
->index
);
3617 /* If this is not a standard conditional jump, we can't parse it. */
3618 jump
= BB_END (test_bb
);
3619 cond
= noce_get_condition (jump
, &cond_earliest
, false);
3623 /* If the conditional jump is more than just a conditional jump, then
3624 we can not do if-conversion on this block. */
3625 if (! onlyjump_p (jump
))
3628 /* We must be comparing objects whose modes imply the size. */
3629 if (GET_MODE (XEXP (cond
, 0)) == BLKmode
)
3632 /* Reverse the comparison code, if necessary. */
3633 code
= GET_CODE (cond
);
3634 if (then_bb
== trap_bb
)
3636 code
= reversed_comparison_code (cond
, jump
);
3637 if (code
== UNKNOWN
)
3641 /* Attempt to generate the conditional trap. */
3642 seq
= gen_cond_trap (code
, copy_rtx (XEXP (cond
, 0)),
3643 copy_rtx (XEXP (cond
, 1)),
3644 TRAP_CODE (PATTERN (trap
)));
3648 /* Emit the new insns before cond_earliest. */
3649 emit_insn_before_setloc (seq
, cond_earliest
, INSN_LOCATOR (trap
));
3651 /* Delete the trap block if possible. */
3652 remove_edge (trap_bb
== then_bb
? then_edge
: else_edge
);
3653 df_set_bb_dirty (test_bb
);
3654 df_set_bb_dirty (then_bb
);
3655 df_set_bb_dirty (else_bb
);
3657 if (EDGE_COUNT (trap_bb
->preds
) == 0)
3659 delete_basic_block (trap_bb
);
3663 /* Wire together the blocks again. */
3664 if (current_ir_type () == IR_RTL_CFGLAYOUT
)
3665 single_succ_edge (test_bb
)->flags
|= EDGE_FALLTHRU
;
3670 lab
= JUMP_LABEL (jump
);
3671 newjump
= emit_jump_insn_after (gen_jump (lab
), jump
);
3672 LABEL_NUSES (lab
) += 1;
3673 JUMP_LABEL (newjump
) = lab
;
3674 emit_barrier_after (newjump
);
3678 if (can_merge_blocks_p (test_bb
, other_bb
))
3680 merge_blocks (test_bb
, other_bb
);
3684 num_updated_if_blocks
++;
3688 /* Subroutine of find_cond_trap: if BB contains only a trap insn,
3692 block_has_only_trap (basic_block bb
)
3696 /* We're not the exit block. */
3697 if (bb
== EXIT_BLOCK_PTR
)
3700 /* The block must have no successors. */
3701 if (EDGE_COUNT (bb
->succs
) > 0)
3704 /* The only instruction in the THEN block must be the trap. */
3705 trap
= first_active_insn (bb
);
3706 if (! (trap
== BB_END (bb
)
3707 && GET_CODE (PATTERN (trap
)) == TRAP_IF
3708 && TRAP_CONDITION (PATTERN (trap
)) == const_true_rtx
))
3714 /* Look for IF-THEN-ELSE cases in which one of THEN or ELSE is
3715 transformable, but not necessarily the other. There need be no
3718 Return TRUE if we were successful at converting the block.
3720 Cases we'd like to look at:
3723 if (test) goto over; // x not live
3731 if (! test) goto label;
3734 if (test) goto E; // x not live
3748 (3) // This one's really only interesting for targets that can do
3749 // multiway branching, e.g. IA-64 BBB bundles. For other targets
3750 // it results in multiple branches on a cache line, which often
3751 // does not sit well with predictors.
3753 if (test1) goto E; // predicted not taken
3769 (A) Don't do (2) if the branch is predicted against the block we're
3770 eliminating. Do it anyway if we can eliminate a branch; this requires
3771 that the sole successor of the eliminated block postdominate the other
3774 (B) With CE, on (3) we can steal from both sides of the if, creating
3783 Again, this is most useful if J postdominates.
3785 (C) CE substitutes for helpful life information.
3787 (D) These heuristics need a lot of work. */
3789 /* Tests for case 1 above. */
3792 find_if_case_1 (basic_block test_bb
, edge then_edge
, edge else_edge
)
3794 basic_block then_bb
= then_edge
->dest
;
3795 basic_block else_bb
= else_edge
->dest
;
3799 /* If we are partitioning hot/cold basic blocks, we don't want to
3800 mess up unconditional or indirect jumps that cross between hot
3803 Basic block partitioning may result in some jumps that appear to
3804 be optimizable (or blocks that appear to be mergeable), but which really
3805 must be left untouched (they are required to make it safely across
3806 partition boundaries). See the comments at the top of
3807 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
3809 if ((BB_END (then_bb
)
3810 && find_reg_note (BB_END (then_bb
), REG_CROSSING_JUMP
, NULL_RTX
))
3811 || (BB_END (test_bb
)
3812 && find_reg_note (BB_END (test_bb
), REG_CROSSING_JUMP
, NULL_RTX
))
3813 || (BB_END (else_bb
)
3814 && find_reg_note (BB_END (else_bb
), REG_CROSSING_JUMP
,
3818 /* THEN has one successor. */
3819 if (!single_succ_p (then_bb
))
3822 /* THEN does not fall through, but is not strange either. */
3823 if (single_succ_edge (then_bb
)->flags
& (EDGE_COMPLEX
| EDGE_FALLTHRU
))
3826 /* THEN has one predecessor. */
3827 if (!single_pred_p (then_bb
))
3830 /* THEN must do something. */
3831 if (forwarder_block_p (then_bb
))
3834 num_possible_if_blocks
++;
3837 "\nIF-CASE-1 found, start %d, then %d\n",
3838 test_bb
->index
, then_bb
->index
);
3840 /* THEN is small. */
3841 if (! cheap_bb_rtx_cost_p (then_bb
,
3842 COSTS_N_INSNS (BRANCH_COST (optimize_bb_for_speed_p (then_edge
->src
),
3843 predictable_edge_p (then_edge
)))))
3846 /* Registers set are dead, or are predicable. */
3847 if (! dead_or_predicable (test_bb
, then_bb
, else_bb
,
3848 single_succ (then_bb
), 1))
3851 /* Conversion went ok, including moving the insns and fixing up the
3852 jump. Adjust the CFG to match. */
3854 /* We can avoid creating a new basic block if then_bb is immediately
3855 followed by else_bb, i.e. deleting then_bb allows test_bb to fall
3858 if (then_bb
->next_bb
== else_bb
3859 && then_bb
->prev_bb
== test_bb
3860 && else_bb
!= EXIT_BLOCK_PTR
)
3862 redirect_edge_succ (FALLTHRU_EDGE (test_bb
), else_bb
);
3866 new_bb
= redirect_edge_and_branch_force (FALLTHRU_EDGE (test_bb
),
3869 df_set_bb_dirty (test_bb
);
3870 df_set_bb_dirty (else_bb
);
3872 then_bb_index
= then_bb
->index
;
3873 delete_basic_block (then_bb
);
3875 /* Make rest of code believe that the newly created block is the THEN_BB
3876 block we removed. */
3879 df_bb_replace (then_bb_index
, new_bb
);
3880 /* Since the fallthru edge was redirected from test_bb to new_bb,
3881 we need to ensure that new_bb is in the same partition as
3882 test bb (you can not fall through across section boundaries). */
3883 BB_COPY_PARTITION (new_bb
, test_bb
);
3887 num_updated_if_blocks
++;
3892 /* Test for case 2 above. */
3895 find_if_case_2 (basic_block test_bb
, edge then_edge
, edge else_edge
)
3897 basic_block then_bb
= then_edge
->dest
;
3898 basic_block else_bb
= else_edge
->dest
;
3902 /* If we are partitioning hot/cold basic blocks, we don't want to
3903 mess up unconditional or indirect jumps that cross between hot
3906 Basic block partitioning may result in some jumps that appear to
3907 be optimizable (or blocks that appear to be mergeable), but which really
3908 must be left untouched (they are required to make it safely across
3909 partition boundaries). See the comments at the top of
3910 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
3912 if ((BB_END (then_bb
)
3913 && find_reg_note (BB_END (then_bb
), REG_CROSSING_JUMP
, NULL_RTX
))
3914 || (BB_END (test_bb
)
3915 && find_reg_note (BB_END (test_bb
), REG_CROSSING_JUMP
, NULL_RTX
))
3916 || (BB_END (else_bb
)
3917 && find_reg_note (BB_END (else_bb
), REG_CROSSING_JUMP
,
3921 /* ELSE has one successor. */
3922 if (!single_succ_p (else_bb
))
3925 else_succ
= single_succ_edge (else_bb
);
3927 /* ELSE outgoing edge is not complex. */
3928 if (else_succ
->flags
& EDGE_COMPLEX
)
3931 /* ELSE has one predecessor. */
3932 if (!single_pred_p (else_bb
))
3935 /* THEN is not EXIT. */
3936 if (then_bb
->index
< NUM_FIXED_BLOCKS
)
3939 /* ELSE is predicted or SUCC(ELSE) postdominates THEN. */
3940 note
= find_reg_note (BB_END (test_bb
), REG_BR_PROB
, NULL_RTX
);
3941 if (note
&& INTVAL (XEXP (note
, 0)) >= REG_BR_PROB_BASE
/ 2)
3943 else if (else_succ
->dest
->index
< NUM_FIXED_BLOCKS
3944 || dominated_by_p (CDI_POST_DOMINATORS
, then_bb
,
3950 num_possible_if_blocks
++;
3953 "\nIF-CASE-2 found, start %d, else %d\n",
3954 test_bb
->index
, else_bb
->index
);
3956 /* ELSE is small. */
3957 if (! cheap_bb_rtx_cost_p (else_bb
,
3958 COSTS_N_INSNS (BRANCH_COST (optimize_bb_for_speed_p (else_edge
->src
),
3959 predictable_edge_p (else_edge
)))))
3962 /* Registers set are dead, or are predicable. */
3963 if (! dead_or_predicable (test_bb
, else_bb
, then_bb
, else_succ
->dest
, 0))
3966 /* Conversion went ok, including moving the insns and fixing up the
3967 jump. Adjust the CFG to match. */
3969 df_set_bb_dirty (test_bb
);
3970 df_set_bb_dirty (then_bb
);
3971 delete_basic_block (else_bb
);
3974 num_updated_if_blocks
++;
3976 /* ??? We may now fallthru from one of THEN's successors into a join
3977 block. Rerun cleanup_cfg? Examine things manually? Wait? */
3982 /* Used by the code above to perform the actual rtl transformations.
3983 Return TRUE if successful.
3985 TEST_BB is the block containing the conditional branch. MERGE_BB
3986 is the block containing the code to manipulate. NEW_DEST is the
3987 label TEST_BB should be branching to after the conversion.
3988 REVERSEP is true if the sense of the branch should be reversed. */
3991 dead_or_predicable (basic_block test_bb
, basic_block merge_bb
,
3992 basic_block other_bb
, basic_block new_dest
, int reversep
)
3994 rtx head
, end
, jump
, earliest
= NULL_RTX
, old_dest
, new_label
= NULL_RTX
;
3995 bitmap merge_set
= NULL
;
3996 /* Number of pending changes. */
3997 int n_validated_changes
= 0;
3999 jump
= BB_END (test_bb
);
4001 /* Find the extent of the real code in the merge block. */
4002 head
= BB_HEAD (merge_bb
);
4003 end
= BB_END (merge_bb
);
4005 while (DEBUG_INSN_P (end
) && end
!= head
)
4006 end
= PREV_INSN (end
);
4008 /* If merge_bb ends with a tablejump, predicating/moving insn's
4009 into test_bb and then deleting merge_bb will result in the jumptable
4010 that follows merge_bb being removed along with merge_bb and then we
4011 get an unresolved reference to the jumptable. */
4012 if (tablejump_p (end
, NULL
, NULL
))
4016 head
= NEXT_INSN (head
);
4017 while (DEBUG_INSN_P (head
) && head
!= end
)
4018 head
= NEXT_INSN (head
);
4023 head
= end
= NULL_RTX
;
4026 head
= NEXT_INSN (head
);
4027 while (DEBUG_INSN_P (head
) && head
!= end
)
4028 head
= NEXT_INSN (head
);
4035 head
= end
= NULL_RTX
;
4038 end
= PREV_INSN (end
);
4039 while (DEBUG_INSN_P (end
) && end
!= head
)
4040 end
= PREV_INSN (end
);
4043 /* Disable handling dead code by conditional execution if the machine needs
4044 to do anything funny with the tests, etc. */
4045 #ifndef IFCVT_MODIFY_TESTS
4046 if (targetm
.have_conditional_execution ())
4048 /* In the conditional execution case, we have things easy. We know
4049 the condition is reversible. We don't have to check life info
4050 because we're going to conditionally execute the code anyway.
4051 All that's left is making sure the insns involved can actually
4056 cond
= cond_exec_get_condition (jump
);
4060 prob_val
= find_reg_note (jump
, REG_BR_PROB
, NULL_RTX
);
4062 prob_val
= XEXP (prob_val
, 0);
4066 enum rtx_code rev
= reversed_comparison_code (cond
, jump
);
4069 cond
= gen_rtx_fmt_ee (rev
, GET_MODE (cond
), XEXP (cond
, 0),
4072 prob_val
= GEN_INT (REG_BR_PROB_BASE
- INTVAL (prob_val
));
4075 if (cond_exec_process_insns (NULL
, head
, end
, cond
, prob_val
, 0)
4076 && verify_changes (0))
4077 n_validated_changes
= num_validated_changes ();
4085 /* If we allocated new pseudos (e.g. in the conditional move
4086 expander called from noce_emit_cmove), we must resize the
4088 if (max_regno
< max_reg_num ())
4089 max_regno
= max_reg_num ();
4091 /* Try the NCE path if the CE path did not result in any changes. */
4092 if (n_validated_changes
== 0)
4098 /* In the non-conditional execution case, we have to verify that there
4099 are no trapping operations, no calls, no references to memory, and
4100 that any registers modified are dead at the branch site. */
4102 if (!any_condjump_p (jump
))
4105 /* Find the extent of the conditional. */
4106 cond
= noce_get_condition (jump
, &earliest
, false);
4110 live
= BITMAP_ALLOC (®_obstack
);
4111 simulate_backwards_to_point (merge_bb
, live
, end
);
4112 success
= can_move_insns_across (head
, end
, earliest
, jump
,
4114 df_get_live_in (other_bb
), NULL
);
4119 /* Collect the set of registers set in MERGE_BB. */
4120 merge_set
= BITMAP_ALLOC (®_obstack
);
4122 FOR_BB_INSNS (merge_bb
, insn
)
4123 if (NONDEBUG_INSN_P (insn
))
4124 df_simulate_find_defs (insn
, merge_set
);
4128 /* We don't want to use normal invert_jump or redirect_jump because
4129 we don't want to delete_insn called. Also, we want to do our own
4130 change group management. */
4132 old_dest
= JUMP_LABEL (jump
);
4133 if (other_bb
!= new_dest
)
4135 new_label
= block_label (new_dest
);
4137 ? ! invert_jump_1 (jump
, new_label
)
4138 : ! redirect_jump_1 (jump
, new_label
))
4142 if (verify_changes (n_validated_changes
))
4143 confirm_change_group ();
4147 if (other_bb
!= new_dest
)
4149 redirect_jump_2 (jump
, old_dest
, new_label
, 0, reversep
);
4151 redirect_edge_succ (BRANCH_EDGE (test_bb
), new_dest
);
4154 gcov_type count
, probability
;
4155 count
= BRANCH_EDGE (test_bb
)->count
;
4156 BRANCH_EDGE (test_bb
)->count
= FALLTHRU_EDGE (test_bb
)->count
;
4157 FALLTHRU_EDGE (test_bb
)->count
= count
;
4158 probability
= BRANCH_EDGE (test_bb
)->probability
;
4159 BRANCH_EDGE (test_bb
)->probability
4160 = FALLTHRU_EDGE (test_bb
)->probability
;
4161 FALLTHRU_EDGE (test_bb
)->probability
= probability
;
4162 update_br_prob_note (test_bb
);
4166 /* Move the insns out of MERGE_BB to before the branch. */
4171 if (end
== BB_END (merge_bb
))
4172 BB_END (merge_bb
) = PREV_INSN (head
);
4174 /* PR 21767: when moving insns above a conditional branch, the REG_EQUAL
4175 notes being moved might become invalid. */
4181 if (! INSN_P (insn
))
4183 note
= find_reg_note (insn
, REG_EQUAL
, NULL_RTX
);
4186 set
= single_set (insn
);
4187 if (!set
|| !function_invariant_p (SET_SRC (set
))
4188 || !function_invariant_p (XEXP (note
, 0)))
4189 remove_note (insn
, note
);
4190 } while (insn
!= end
&& (insn
= NEXT_INSN (insn
)));
4192 /* PR46315: when moving insns above a conditional branch, the REG_EQUAL
4193 notes referring to the registers being set might become invalid. */
4199 EXECUTE_IF_SET_IN_BITMAP (merge_set
, 0, i
, bi
)
4200 remove_reg_equal_equiv_notes_for_regno (i
);
4202 BITMAP_FREE (merge_set
);
4205 reorder_insns (head
, end
, PREV_INSN (earliest
));
4208 /* Remove the jump and edge if we can. */
4209 if (other_bb
== new_dest
)
4212 remove_edge (BRANCH_EDGE (test_bb
));
4213 /* ??? Can't merge blocks here, as then_bb is still in use.
4214 At minimum, the merge will get done just before bb-reorder. */
4223 BITMAP_FREE (merge_set
);
4228 /* Main entry point for all if-conversion. */
4238 df_live_add_problem ();
4239 df_live_set_all_dirty ();
4242 num_possible_if_blocks
= 0;
4243 num_updated_if_blocks
= 0;
4244 num_true_changes
= 0;
4246 loop_optimizer_init (AVOID_CFG_MODIFICATIONS
);
4247 mark_loop_exit_edges ();
4248 loop_optimizer_finalize ();
4249 free_dominance_info (CDI_DOMINATORS
);
4251 /* Compute postdominators. */
4252 calculate_dominance_info (CDI_POST_DOMINATORS
);
4254 df_set_flags (DF_LR_RUN_DCE
);
4256 /* Go through each of the basic blocks looking for things to convert. If we
4257 have conditional execution, we make multiple passes to allow us to handle
4258 IF-THEN{-ELSE} blocks within other IF-THEN{-ELSE} blocks. */
4263 /* Only need to do dce on the first pass. */
4264 df_clear_flags (DF_LR_RUN_DCE
);
4265 cond_exec_changed_p
= FALSE
;
4268 #ifdef IFCVT_MULTIPLE_DUMPS
4269 if (dump_file
&& pass
> 1)
4270 fprintf (dump_file
, "\n\n========== Pass %d ==========\n", pass
);
4276 while (!df_get_bb_dirty (bb
)
4277 && (new_bb
= find_if_header (bb
, pass
)) != NULL
)
4281 #ifdef IFCVT_MULTIPLE_DUMPS
4282 if (dump_file
&& cond_exec_changed_p
)
4284 if (dump_flags
& TDF_SLIM
)
4285 print_rtl_slim_with_bb (dump_file
, get_insns (), dump_flags
);
4287 print_rtl_with_bb (dump_file
, get_insns ());
4291 while (cond_exec_changed_p
);
4293 #ifdef IFCVT_MULTIPLE_DUMPS
4295 fprintf (dump_file
, "\n\n========== no more changes\n");
4298 free_dominance_info (CDI_POST_DOMINATORS
);
4303 clear_aux_for_blocks ();
4305 /* If we allocated new pseudos, we must resize the array for sched1. */
4306 if (max_regno
< max_reg_num ())
4307 max_regno
= max_reg_num ();
4309 /* Write the final stats. */
4310 if (dump_file
&& num_possible_if_blocks
> 0)
4313 "\n%d possible IF blocks searched.\n",
4314 num_possible_if_blocks
);
4316 "%d IF blocks converted.\n",
4317 num_updated_if_blocks
);
4319 "%d true changes made.\n\n\n",
4324 df_remove_problem (df_live
);
4326 #ifdef ENABLE_CHECKING
4327 verify_flow_info ();
4332 gate_handle_if_conversion (void)
4334 return (optimize
> 0)
4335 && dbg_cnt (if_conversion
);
4338 /* If-conversion and CFG cleanup. */
4340 rest_of_handle_if_conversion (void)
4342 if (flag_if_conversion
)
4345 dump_flow_info (dump_file
, dump_flags
);
4346 cleanup_cfg (CLEANUP_EXPENSIVE
);
4354 struct rtl_opt_pass pass_rtl_ifcvt
=
4359 gate_handle_if_conversion
, /* gate */
4360 rest_of_handle_if_conversion
, /* execute */
4363 0, /* static_pass_number */
4364 TV_IFCVT
, /* tv_id */
4365 0, /* properties_required */
4366 0, /* properties_provided */
4367 0, /* properties_destroyed */
4368 0, /* todo_flags_start */
4369 TODO_df_finish
| TODO_verify_rtl_sharing
|
4370 TODO_dump_func
/* todo_flags_finish */
4375 gate_handle_if_after_combine (void)
4377 return optimize
> 0 && flag_if_conversion
4378 && dbg_cnt (if_after_combine
);
4382 /* Rerun if-conversion, as combine may have simplified things enough
4383 to now meet sequence length restrictions. */
4385 rest_of_handle_if_after_combine (void)
4391 struct rtl_opt_pass pass_if_after_combine
=
4396 gate_handle_if_after_combine
, /* gate */
4397 rest_of_handle_if_after_combine
, /* execute */
4400 0, /* static_pass_number */
4401 TV_IFCVT
, /* tv_id */
4402 0, /* properties_required */
4403 0, /* properties_provided */
4404 0, /* properties_destroyed */
4405 0, /* todo_flags_start */
4406 TODO_df_finish
| TODO_verify_rtl_sharing
|
4408 TODO_ggc_collect
/* todo_flags_finish */
4414 gate_handle_if_after_reload (void)
4416 return optimize
> 0 && flag_if_conversion2
4417 && dbg_cnt (if_after_reload
);
4421 rest_of_handle_if_after_reload (void)
4428 struct rtl_opt_pass pass_if_after_reload
=
4433 gate_handle_if_after_reload
, /* gate */
4434 rest_of_handle_if_after_reload
, /* execute */
4437 0, /* static_pass_number */
4438 TV_IFCVT2
, /* tv_id */
4439 0, /* properties_required */
4440 0, /* properties_provided */
4441 0, /* properties_destroyed */
4442 0, /* todo_flags_start */
4443 TODO_df_finish
| TODO_verify_rtl_sharing
|
4445 TODO_ggc_collect
/* todo_flags_finish */