1 /* If-conversion support.
2 Copyright (C) 2000-2014 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it
7 under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3, or (at your option)
11 GCC is distributed in the hope that it will be useful, but WITHOUT
12 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
13 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
14 License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
22 #include "coretypes.h"
29 #include "insn-config.h"
32 #include "hard-reg-set.h"
33 #include "basic-block.h"
37 #include "diagnostic-core.h"
41 #include "tree-pass.h"
44 #include "pointer-set.h"
47 #ifndef HAVE_conditional_move
48 #define HAVE_conditional_move 0
60 #ifndef MAX_CONDITIONAL_EXECUTE
61 #define MAX_CONDITIONAL_EXECUTE \
62 (BRANCH_COST (optimize_function_for_speed_p (cfun), false) \
66 #define IFCVT_MULTIPLE_DUMPS 1
68 #define NULL_BLOCK ((basic_block) NULL)
70 /* True if after combine pass. */
71 static bool ifcvt_after_combine
;
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, 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
*, rtx
, rtx
, rtx
, int, 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
*);
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
*);
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 (active_insn_p (insn
) && !JUMP_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.
136 The cost of the non-jump insns in BB is scaled by REG_BR_PROB_BASE
137 as those insns are being speculated. MAX_COST is scaled with SCALE
138 plus a small fudge factor. */
141 cheap_bb_rtx_cost_p (const_basic_block bb
, int scale
, int max_cost
)
144 rtx insn
= BB_HEAD (bb
);
145 bool speed
= optimize_bb_for_speed_p (bb
);
147 /* Set scale to REG_BR_PROB_BASE to void the identical scaling
148 applied to insn_rtx_cost when optimizing for size. Only do
149 this after combine because if-conversion might interfere with
150 passes before combine.
152 Use optimize_function_for_speed_p instead of the pre-defined
153 variable speed to make sure it is set to same value for all
154 basic blocks in one if-conversion transformation. */
155 if (!optimize_function_for_speed_p (cfun
) && ifcvt_after_combine
)
156 scale
= REG_BR_PROB_BASE
;
157 /* Our branch probability/scaling factors are just estimates and don't
158 account for cases where we can get speculation for free and other
159 secondary benefits. So we fudge the scale factor to make speculating
160 appear a little more profitable when optimizing for performance. */
162 scale
+= REG_BR_PROB_BASE
/ 8;
169 if (NONJUMP_INSN_P (insn
))
171 int cost
= insn_rtx_cost (PATTERN (insn
), speed
) * REG_BR_PROB_BASE
;
175 /* If this instruction is the load or set of a "stack" register,
176 such as a floating point register on x87, then the cost of
177 speculatively executing this insn may need to include
178 the additional cost of popping its result off of the
179 register stack. Unfortunately, correctly recognizing and
180 accounting for this additional overhead is tricky, so for
181 now we simply prohibit such speculative execution. */
184 rtx set
= single_set (insn
);
185 if (set
&& STACK_REG_P (SET_DEST (set
)))
191 if (count
>= max_cost
)
194 else if (CALL_P (insn
))
197 if (insn
== BB_END (bb
))
199 insn
= NEXT_INSN (insn
);
205 /* Return the first non-jump active insn in the basic block. */
208 first_active_insn (basic_block bb
)
210 rtx insn
= BB_HEAD (bb
);
214 if (insn
== BB_END (bb
))
216 insn
= NEXT_INSN (insn
);
219 while (NOTE_P (insn
) || DEBUG_INSN_P (insn
))
221 if (insn
== BB_END (bb
))
223 insn
= NEXT_INSN (insn
);
232 /* Return the last non-jump active (non-jump) insn in the basic block. */
235 last_active_insn (basic_block bb
, int skip_use_p
)
237 rtx insn
= BB_END (bb
);
238 rtx head
= BB_HEAD (bb
);
242 || DEBUG_INSN_P (insn
)
244 && NONJUMP_INSN_P (insn
)
245 && GET_CODE (PATTERN (insn
)) == USE
))
249 insn
= PREV_INSN (insn
);
258 /* Return the active insn before INSN inside basic block CURR_BB. */
261 find_active_insn_before (basic_block curr_bb
, rtx insn
)
263 if (!insn
|| insn
== BB_HEAD (curr_bb
))
266 while ((insn
= PREV_INSN (insn
)) != NULL_RTX
)
268 if (NONJUMP_INSN_P (insn
) || JUMP_P (insn
) || CALL_P (insn
))
271 /* No other active insn all the way to the start of the basic block. */
272 if (insn
== BB_HEAD (curr_bb
))
279 /* Return the active insn after INSN inside basic block CURR_BB. */
282 find_active_insn_after (basic_block curr_bb
, rtx insn
)
284 if (!insn
|| insn
== BB_END (curr_bb
))
287 while ((insn
= NEXT_INSN (insn
)) != NULL_RTX
)
289 if (NONJUMP_INSN_P (insn
) || JUMP_P (insn
) || CALL_P (insn
))
292 /* No other active insn all the way to the end of the basic block. */
293 if (insn
== BB_END (curr_bb
))
300 /* Return the basic block reached by falling though the basic block BB. */
303 block_fallthru (basic_block bb
)
305 edge e
= find_fallthru_edge (bb
->succs
);
307 return (e
) ? e
->dest
: NULL_BLOCK
;
310 /* Return true if RTXs A and B can be safely interchanged. */
313 rtx_interchangeable_p (const_rtx a
, const_rtx b
)
315 if (!rtx_equal_p (a
, b
))
318 if (GET_CODE (a
) != MEM
)
321 /* A dead type-unsafe memory reference is legal, but a live type-unsafe memory
322 reference is not. Interchanging a dead type-unsafe memory reference with
323 a live type-safe one creates a live type-unsafe memory reference, in other
324 words, it makes the program illegal.
325 We check here conservatively whether the two memory references have equal
326 memory attributes. */
328 return mem_attrs_eq_p (get_mem_attrs (a
), get_mem_attrs (b
));
332 /* Go through a bunch of insns, converting them to conditional
333 execution format if possible. Return TRUE if all of the non-note
334 insns were processed. */
337 cond_exec_process_insns (ce_if_block
*ce_info ATTRIBUTE_UNUSED
,
338 /* if block information */rtx start
,
339 /* first insn to look at */rtx end
,
340 /* last insn to look at */rtx test
,
341 /* conditional execution test */int prob_val
,
342 /* probability of branch taken. */int mod_ok
)
344 int must_be_last
= FALSE
;
352 for (insn
= start
; ; insn
= NEXT_INSN (insn
))
354 /* dwarf2out can't cope with conditional prologues. */
355 if (NOTE_P (insn
) && NOTE_KIND (insn
) == NOTE_INSN_PROLOGUE_END
)
358 if (NOTE_P (insn
) || DEBUG_INSN_P (insn
))
361 gcc_assert (NONJUMP_INSN_P (insn
) || CALL_P (insn
));
363 /* dwarf2out can't cope with conditional unwind info. */
364 if (RTX_FRAME_RELATED_P (insn
))
367 /* Remove USE insns that get in the way. */
368 if (reload_completed
&& GET_CODE (PATTERN (insn
)) == USE
)
370 /* ??? Ug. Actually unlinking the thing is problematic,
371 given what we'd have to coordinate with our callers. */
372 SET_INSN_DELETED (insn
);
376 /* Last insn wasn't last? */
380 if (modified_in_p (test
, insn
))
387 /* Now build the conditional form of the instruction. */
388 pattern
= PATTERN (insn
);
389 xtest
= copy_rtx (test
);
391 /* If this is already a COND_EXEC, rewrite the test to be an AND of the
393 if (GET_CODE (pattern
) == COND_EXEC
)
395 if (GET_MODE (xtest
) != GET_MODE (COND_EXEC_TEST (pattern
)))
398 xtest
= gen_rtx_AND (GET_MODE (xtest
), xtest
,
399 COND_EXEC_TEST (pattern
));
400 pattern
= COND_EXEC_CODE (pattern
);
403 pattern
= gen_rtx_COND_EXEC (VOIDmode
, xtest
, pattern
);
405 /* If the machine needs to modify the insn being conditionally executed,
406 say for example to force a constant integer operand into a temp
407 register, do so here. */
408 #ifdef IFCVT_MODIFY_INSN
409 IFCVT_MODIFY_INSN (ce_info
, pattern
, insn
);
414 validate_change (insn
, &PATTERN (insn
), pattern
, 1);
416 if (CALL_P (insn
) && prob_val
>= 0)
417 validate_change (insn
, ®_NOTES (insn
),
418 gen_rtx_INT_LIST ((enum machine_mode
) REG_BR_PROB
,
419 prob_val
, REG_NOTES (insn
)), 1);
429 /* Return the condition for a jump. Do not do any special processing. */
432 cond_exec_get_condition (rtx jump
)
436 if (any_condjump_p (jump
))
437 test_if
= SET_SRC (pc_set (jump
));
440 cond
= XEXP (test_if
, 0);
442 /* If this branches to JUMP_LABEL when the condition is false,
443 reverse the condition. */
444 if (GET_CODE (XEXP (test_if
, 2)) == LABEL_REF
445 && XEXP (XEXP (test_if
, 2), 0) == JUMP_LABEL (jump
))
447 enum rtx_code rev
= reversed_comparison_code (cond
, jump
);
451 cond
= gen_rtx_fmt_ee (rev
, GET_MODE (cond
), XEXP (cond
, 0),
458 /* Given a simple IF-THEN or IF-THEN-ELSE block, attempt to convert it
459 to conditional execution. Return TRUE if we were successful at
460 converting the block. */
463 cond_exec_process_if_block (ce_if_block
* ce_info
,
464 /* if block information */int do_multiple_p
)
466 basic_block test_bb
= ce_info
->test_bb
; /* last test block */
467 basic_block then_bb
= ce_info
->then_bb
; /* THEN */
468 basic_block else_bb
= ce_info
->else_bb
; /* ELSE or NULL */
469 rtx test_expr
; /* expression in IF_THEN_ELSE that is tested */
470 rtx then_start
; /* first insn in THEN block */
471 rtx then_end
; /* last insn + 1 in THEN block */
472 rtx else_start
= NULL_RTX
; /* first insn in ELSE block or NULL */
473 rtx else_end
= NULL_RTX
; /* last insn + 1 in ELSE block */
474 int max
; /* max # of insns to convert. */
475 int then_mod_ok
; /* whether conditional mods are ok in THEN */
476 rtx true_expr
; /* test for else block insns */
477 rtx false_expr
; /* test for then block insns */
478 int true_prob_val
; /* probability of else block */
479 int false_prob_val
; /* probability of then block */
480 rtx then_last_head
= NULL_RTX
; /* Last match at the head of THEN */
481 rtx else_last_head
= NULL_RTX
; /* Last match at the head of ELSE */
482 rtx then_first_tail
= NULL_RTX
; /* First match at the tail of THEN */
483 rtx else_first_tail
= NULL_RTX
; /* First match at the tail of ELSE */
484 int then_n_insns
, else_n_insns
, n_insns
;
485 enum rtx_code false_code
;
488 /* If test is comprised of && or || elements, and we've failed at handling
489 all of them together, just use the last test if it is the special case of
490 && elements without an ELSE block. */
491 if (!do_multiple_p
&& ce_info
->num_multiple_test_blocks
)
493 if (else_bb
|| ! ce_info
->and_and_p
)
496 ce_info
->test_bb
= test_bb
= ce_info
->last_test_bb
;
497 ce_info
->num_multiple_test_blocks
= 0;
498 ce_info
->num_and_and_blocks
= 0;
499 ce_info
->num_or_or_blocks
= 0;
502 /* Find the conditional jump to the ELSE or JOIN part, and isolate
504 test_expr
= cond_exec_get_condition (BB_END (test_bb
));
508 /* If the conditional jump is more than just a conditional jump,
509 then we can not do conditional execution conversion on this block. */
510 if (! onlyjump_p (BB_END (test_bb
)))
513 /* Collect the bounds of where we're to search, skipping any labels, jumps
514 and notes at the beginning and end of the block. Then count the total
515 number of insns and see if it is small enough to convert. */
516 then_start
= first_active_insn (then_bb
);
517 then_end
= last_active_insn (then_bb
, TRUE
);
518 then_n_insns
= ce_info
->num_then_insns
= count_bb_insns (then_bb
);
519 n_insns
= then_n_insns
;
520 max
= MAX_CONDITIONAL_EXECUTE
;
527 else_start
= first_active_insn (else_bb
);
528 else_end
= last_active_insn (else_bb
, TRUE
);
529 else_n_insns
= ce_info
->num_else_insns
= count_bb_insns (else_bb
);
530 n_insns
+= else_n_insns
;
532 /* Look for matching sequences at the head and tail of the two blocks,
533 and limit the range of insns to be converted if possible. */
534 n_matching
= flow_find_cross_jump (then_bb
, else_bb
,
535 &then_first_tail
, &else_first_tail
,
537 if (then_first_tail
== BB_HEAD (then_bb
))
538 then_start
= then_end
= NULL_RTX
;
539 if (else_first_tail
== BB_HEAD (else_bb
))
540 else_start
= else_end
= NULL_RTX
;
545 then_end
= find_active_insn_before (then_bb
, then_first_tail
);
547 else_end
= find_active_insn_before (else_bb
, else_first_tail
);
548 n_insns
-= 2 * n_matching
;
553 && then_n_insns
> n_matching
554 && else_n_insns
> n_matching
)
556 int longest_match
= MIN (then_n_insns
- n_matching
,
557 else_n_insns
- n_matching
);
559 = flow_find_head_matching_sequence (then_bb
, else_bb
,
568 /* We won't pass the insns in the head sequence to
569 cond_exec_process_insns, so we need to test them here
570 to make sure that they don't clobber the condition. */
571 for (insn
= BB_HEAD (then_bb
);
572 insn
!= NEXT_INSN (then_last_head
);
573 insn
= NEXT_INSN (insn
))
574 if (!LABEL_P (insn
) && !NOTE_P (insn
)
575 && !DEBUG_INSN_P (insn
)
576 && modified_in_p (test_expr
, insn
))
580 if (then_last_head
== then_end
)
581 then_start
= then_end
= NULL_RTX
;
582 if (else_last_head
== else_end
)
583 else_start
= else_end
= NULL_RTX
;
588 then_start
= find_active_insn_after (then_bb
, then_last_head
);
590 else_start
= find_active_insn_after (else_bb
, else_last_head
);
591 n_insns
-= 2 * n_matching
;
599 /* Map test_expr/test_jump into the appropriate MD tests to use on
600 the conditionally executed code. */
602 true_expr
= test_expr
;
604 false_code
= reversed_comparison_code (true_expr
, BB_END (test_bb
));
605 if (false_code
!= UNKNOWN
)
606 false_expr
= gen_rtx_fmt_ee (false_code
, GET_MODE (true_expr
),
607 XEXP (true_expr
, 0), XEXP (true_expr
, 1));
609 false_expr
= NULL_RTX
;
611 #ifdef IFCVT_MODIFY_TESTS
612 /* If the machine description needs to modify the tests, such as setting a
613 conditional execution register from a comparison, it can do so here. */
614 IFCVT_MODIFY_TESTS (ce_info
, true_expr
, false_expr
);
616 /* See if the conversion failed. */
617 if (!true_expr
|| !false_expr
)
621 note
= find_reg_note (BB_END (test_bb
), REG_BR_PROB
, NULL_RTX
);
624 true_prob_val
= XINT (note
, 0);
625 false_prob_val
= REG_BR_PROB_BASE
- true_prob_val
;
633 /* If we have && or || tests, do them here. These tests are in the adjacent
634 blocks after the first block containing the test. */
635 if (ce_info
->num_multiple_test_blocks
> 0)
637 basic_block bb
= test_bb
;
638 basic_block last_test_bb
= ce_info
->last_test_bb
;
647 enum rtx_code f_code
;
649 bb
= block_fallthru (bb
);
650 start
= first_active_insn (bb
);
651 end
= last_active_insn (bb
, TRUE
);
653 && ! cond_exec_process_insns (ce_info
, start
, end
, false_expr
,
654 false_prob_val
, FALSE
))
657 /* If the conditional jump is more than just a conditional jump, then
658 we can not do conditional execution conversion on this block. */
659 if (! onlyjump_p (BB_END (bb
)))
662 /* Find the conditional jump and isolate the test. */
663 t
= cond_exec_get_condition (BB_END (bb
));
667 f_code
= reversed_comparison_code (t
, BB_END (bb
));
668 if (f_code
== UNKNOWN
)
671 f
= gen_rtx_fmt_ee (f_code
, GET_MODE (t
), XEXP (t
, 0), XEXP (t
, 1));
672 if (ce_info
->and_and_p
)
674 t
= gen_rtx_AND (GET_MODE (t
), true_expr
, t
);
675 f
= gen_rtx_IOR (GET_MODE (t
), false_expr
, f
);
679 t
= gen_rtx_IOR (GET_MODE (t
), true_expr
, t
);
680 f
= gen_rtx_AND (GET_MODE (t
), false_expr
, f
);
683 /* If the machine description needs to modify the tests, such as
684 setting a conditional execution register from a comparison, it can
686 #ifdef IFCVT_MODIFY_MULTIPLE_TESTS
687 IFCVT_MODIFY_MULTIPLE_TESTS (ce_info
, bb
, t
, f
);
689 /* See if the conversion failed. */
697 while (bb
!= last_test_bb
);
700 /* For IF-THEN-ELSE blocks, we don't allow modifications of the test
701 on then THEN block. */
702 then_mod_ok
= (else_bb
== NULL_BLOCK
);
704 /* Go through the THEN and ELSE blocks converting the insns if possible
705 to conditional execution. */
709 || ! cond_exec_process_insns (ce_info
, then_start
, then_end
,
710 false_expr
, false_prob_val
,
714 if (else_bb
&& else_end
715 && ! cond_exec_process_insns (ce_info
, else_start
, else_end
,
716 true_expr
, true_prob_val
, TRUE
))
719 /* If we cannot apply the changes, fail. Do not go through the normal fail
720 processing, since apply_change_group will call cancel_changes. */
721 if (! apply_change_group ())
723 #ifdef IFCVT_MODIFY_CANCEL
724 /* Cancel any machine dependent changes. */
725 IFCVT_MODIFY_CANCEL (ce_info
);
730 #ifdef IFCVT_MODIFY_FINAL
731 /* Do any machine dependent final modifications. */
732 IFCVT_MODIFY_FINAL (ce_info
);
735 /* Conversion succeeded. */
737 fprintf (dump_file
, "%d insn%s converted to conditional execution.\n",
738 n_insns
, (n_insns
== 1) ? " was" : "s were");
740 /* Merge the blocks! If we had matching sequences, make sure to delete one
741 copy at the appropriate location first: delete the copy in the THEN branch
742 for a tail sequence so that the remaining one is executed last for both
743 branches, and delete the copy in the ELSE branch for a head sequence so
744 that the remaining one is executed first for both branches. */
747 rtx from
= then_first_tail
;
749 from
= find_active_insn_after (then_bb
, from
);
750 delete_insn_chain (from
, BB_END (then_bb
), false);
753 delete_insn_chain (first_active_insn (else_bb
), else_last_head
, false);
755 merge_if_block (ce_info
);
756 cond_exec_changed_p
= TRUE
;
760 #ifdef IFCVT_MODIFY_CANCEL
761 /* Cancel any machine dependent changes. */
762 IFCVT_MODIFY_CANCEL (ce_info
);
769 /* Used by noce_process_if_block to communicate with its subroutines.
771 The subroutines know that A and B may be evaluated freely. They
772 know that X is a register. They should insert new instructions
773 before cond_earliest. */
777 /* The basic blocks that make up the IF-THEN-{ELSE-,}JOIN block. */
778 basic_block test_bb
, then_bb
, else_bb
, join_bb
;
780 /* The jump that ends TEST_BB. */
783 /* The jump condition. */
786 /* New insns should be inserted before this one. */
789 /* Insns in the THEN and ELSE block. There is always just this
790 one insns in those blocks. The insns are single_set insns.
791 If there was no ELSE block, INSN_B is the last insn before
792 COND_EARLIEST, or NULL_RTX. In the former case, the insn
793 operands are still valid, as if INSN_B was moved down below
797 /* The SET_SRC of INSN_A and INSN_B. */
800 /* The SET_DEST of INSN_A. */
803 /* True if this if block is not canonical. In the canonical form of
804 if blocks, the THEN_BB is the block reached via the fallthru edge
805 from TEST_BB. For the noce transformations, we allow the symmetric
807 bool then_else_reversed
;
809 /* Estimated cost of the particular branch instruction. */
813 static rtx
noce_emit_store_flag (struct noce_if_info
*, rtx
, int, int);
814 static int noce_try_move (struct noce_if_info
*);
815 static int noce_try_store_flag (struct noce_if_info
*);
816 static int noce_try_addcc (struct noce_if_info
*);
817 static int noce_try_store_flag_constants (struct noce_if_info
*);
818 static int noce_try_store_flag_mask (struct noce_if_info
*);
819 static rtx
noce_emit_cmove (struct noce_if_info
*, rtx
, enum rtx_code
, rtx
,
821 static int noce_try_cmove (struct noce_if_info
*);
822 static int noce_try_cmove_arith (struct noce_if_info
*);
823 static rtx
noce_get_alt_condition (struct noce_if_info
*, rtx
, rtx
*);
824 static int noce_try_minmax (struct noce_if_info
*);
825 static int noce_try_abs (struct noce_if_info
*);
826 static int noce_try_sign_mask (struct noce_if_info
*);
828 /* Helper function for noce_try_store_flag*. */
831 noce_emit_store_flag (struct noce_if_info
*if_info
, rtx x
, int reversep
,
834 rtx cond
= if_info
->cond
;
838 cond_complex
= (! general_operand (XEXP (cond
, 0), VOIDmode
)
839 || ! general_operand (XEXP (cond
, 1), VOIDmode
));
841 /* If earliest == jump, or when the condition is complex, try to
842 build the store_flag insn directly. */
846 rtx set
= pc_set (if_info
->jump
);
847 cond
= XEXP (SET_SRC (set
), 0);
848 if (GET_CODE (XEXP (SET_SRC (set
), 2)) == LABEL_REF
849 && XEXP (XEXP (SET_SRC (set
), 2), 0) == JUMP_LABEL (if_info
->jump
))
850 reversep
= !reversep
;
851 if (if_info
->then_else_reversed
)
852 reversep
= !reversep
;
856 code
= reversed_comparison_code (cond
, if_info
->jump
);
858 code
= GET_CODE (cond
);
860 if ((if_info
->cond_earliest
== if_info
->jump
|| cond_complex
)
861 && (normalize
== 0 || STORE_FLAG_VALUE
== normalize
))
865 tmp
= gen_rtx_fmt_ee (code
, GET_MODE (x
), XEXP (cond
, 0),
867 tmp
= gen_rtx_SET (VOIDmode
, x
, tmp
);
870 tmp
= emit_insn (tmp
);
872 if (recog_memoized (tmp
) >= 0)
878 if_info
->cond_earliest
= if_info
->jump
;
886 /* Don't even try if the comparison operands or the mode of X are weird. */
887 if (cond_complex
|| !SCALAR_INT_MODE_P (GET_MODE (x
)))
890 return emit_store_flag (x
, code
, XEXP (cond
, 0),
891 XEXP (cond
, 1), VOIDmode
,
892 (code
== LTU
|| code
== LEU
893 || code
== GEU
|| code
== GTU
), normalize
);
896 /* Emit instruction to move an rtx, possibly into STRICT_LOW_PART.
897 X is the destination/target and Y is the value to copy. */
900 noce_emit_move_insn (rtx x
, rtx y
)
902 enum machine_mode outmode
;
906 if (GET_CODE (x
) != STRICT_LOW_PART
)
908 rtx seq
, insn
, target
;
912 /* Check that the SET_SRC is reasonable before calling emit_move_insn,
913 otherwise construct a suitable SET pattern ourselves. */
914 insn
= (OBJECT_P (y
) || CONSTANT_P (y
) || GET_CODE (y
) == SUBREG
)
915 ? emit_move_insn (x
, y
)
916 : emit_insn (gen_rtx_SET (VOIDmode
, x
, y
));
920 if (recog_memoized (insn
) <= 0)
922 if (GET_CODE (x
) == ZERO_EXTRACT
)
924 rtx op
= XEXP (x
, 0);
925 unsigned HOST_WIDE_INT size
= INTVAL (XEXP (x
, 1));
926 unsigned HOST_WIDE_INT start
= INTVAL (XEXP (x
, 2));
928 /* store_bit_field expects START to be relative to
929 BYTES_BIG_ENDIAN and adjusts this value for machines with
930 BITS_BIG_ENDIAN != BYTES_BIG_ENDIAN. In order to be able to
931 invoke store_bit_field again it is necessary to have the START
932 value from the first call. */
933 if (BITS_BIG_ENDIAN
!= BYTES_BIG_ENDIAN
)
936 start
= BITS_PER_UNIT
- start
- size
;
939 gcc_assert (REG_P (op
));
940 start
= BITS_PER_WORD
- start
- size
;
944 gcc_assert (start
< (MEM_P (op
) ? BITS_PER_UNIT
: BITS_PER_WORD
));
945 store_bit_field (op
, size
, start
, 0, 0, GET_MODE (x
), y
);
949 switch (GET_RTX_CLASS (GET_CODE (y
)))
952 ot
= code_to_optab (GET_CODE (y
));
956 target
= expand_unop (GET_MODE (y
), ot
, XEXP (y
, 0), x
, 0);
957 if (target
!= NULL_RTX
)
960 emit_move_insn (x
, target
);
969 ot
= code_to_optab (GET_CODE (y
));
973 target
= expand_binop (GET_MODE (y
), ot
,
974 XEXP (y
, 0), XEXP (y
, 1),
976 if (target
!= NULL_RTX
)
979 emit_move_insn (x
, target
);
996 inner
= XEXP (outer
, 0);
997 outmode
= GET_MODE (outer
);
998 bitpos
= SUBREG_BYTE (outer
) * BITS_PER_UNIT
;
999 store_bit_field (inner
, GET_MODE_BITSIZE (outmode
), bitpos
,
1003 /* Return sequence of instructions generated by if conversion. This
1004 function calls end_sequence() to end the current stream, ensures
1005 that are instructions are unshared, recognizable non-jump insns.
1006 On failure, this function returns a NULL_RTX. */
1009 end_ifcvt_sequence (struct noce_if_info
*if_info
)
1012 rtx seq
= get_insns ();
1014 set_used_flags (if_info
->x
);
1015 set_used_flags (if_info
->cond
);
1016 set_used_flags (if_info
->a
);
1017 set_used_flags (if_info
->b
);
1018 unshare_all_rtl_in_chain (seq
);
1021 /* Make sure that all of the instructions emitted are recognizable,
1022 and that we haven't introduced a new jump instruction.
1023 As an exercise for the reader, build a general mechanism that
1024 allows proper placement of required clobbers. */
1025 for (insn
= seq
; insn
; insn
= NEXT_INSN (insn
))
1027 || recog_memoized (insn
) == -1)
1033 /* Convert "if (a != b) x = a; else x = b" into "x = a" and
1034 "if (a == b) x = a; else x = b" into "x = b". */
1037 noce_try_move (struct noce_if_info
*if_info
)
1039 rtx cond
= if_info
->cond
;
1040 enum rtx_code code
= GET_CODE (cond
);
1043 if (code
!= NE
&& code
!= EQ
)
1046 /* This optimization isn't valid if either A or B could be a NaN
1047 or a signed zero. */
1048 if (HONOR_NANS (GET_MODE (if_info
->x
))
1049 || HONOR_SIGNED_ZEROS (GET_MODE (if_info
->x
)))
1052 /* Check whether the operands of the comparison are A and in
1054 if ((rtx_equal_p (if_info
->a
, XEXP (cond
, 0))
1055 && rtx_equal_p (if_info
->b
, XEXP (cond
, 1)))
1056 || (rtx_equal_p (if_info
->a
, XEXP (cond
, 1))
1057 && rtx_equal_p (if_info
->b
, XEXP (cond
, 0))))
1059 if (!rtx_interchangeable_p (if_info
->a
, if_info
->b
))
1062 y
= (code
== EQ
) ? if_info
->a
: if_info
->b
;
1064 /* Avoid generating the move if the source is the destination. */
1065 if (! rtx_equal_p (if_info
->x
, y
))
1068 noce_emit_move_insn (if_info
->x
, y
);
1069 seq
= end_ifcvt_sequence (if_info
);
1073 emit_insn_before_setloc (seq
, if_info
->jump
,
1074 INSN_LOCATION (if_info
->insn_a
));
1081 /* Convert "if (test) x = 1; else x = 0".
1083 Only try 0 and STORE_FLAG_VALUE here. Other combinations will be
1084 tried in noce_try_store_flag_constants after noce_try_cmove has had
1085 a go at the conversion. */
1088 noce_try_store_flag (struct noce_if_info
*if_info
)
1093 if (CONST_INT_P (if_info
->b
)
1094 && INTVAL (if_info
->b
) == STORE_FLAG_VALUE
1095 && if_info
->a
== const0_rtx
)
1097 else if (if_info
->b
== const0_rtx
1098 && CONST_INT_P (if_info
->a
)
1099 && INTVAL (if_info
->a
) == STORE_FLAG_VALUE
1100 && (reversed_comparison_code (if_info
->cond
, if_info
->jump
)
1108 target
= noce_emit_store_flag (if_info
, if_info
->x
, reversep
, 0);
1111 if (target
!= if_info
->x
)
1112 noce_emit_move_insn (if_info
->x
, target
);
1114 seq
= end_ifcvt_sequence (if_info
);
1118 emit_insn_before_setloc (seq
, if_info
->jump
,
1119 INSN_LOCATION (if_info
->insn_a
));
1129 /* Convert "if (test) x = a; else x = b", for A and B constant. */
1132 noce_try_store_flag_constants (struct noce_if_info
*if_info
)
1136 HOST_WIDE_INT itrue
, ifalse
, diff
, tmp
;
1137 int normalize
, can_reverse
;
1138 enum machine_mode mode
;
1140 if (CONST_INT_P (if_info
->a
)
1141 && CONST_INT_P (if_info
->b
))
1143 mode
= GET_MODE (if_info
->x
);
1144 ifalse
= INTVAL (if_info
->a
);
1145 itrue
= INTVAL (if_info
->b
);
1147 diff
= (unsigned HOST_WIDE_INT
) itrue
- ifalse
;
1148 /* Make sure we can represent the difference between the two values. */
1150 != ((ifalse
< 0) != (itrue
< 0) ? ifalse
< 0 : ifalse
< itrue
))
1153 diff
= trunc_int_for_mode (diff
, mode
);
1155 can_reverse
= (reversed_comparison_code (if_info
->cond
, if_info
->jump
)
1159 if (diff
== STORE_FLAG_VALUE
|| diff
== -STORE_FLAG_VALUE
)
1161 else if (ifalse
== 0 && exact_log2 (itrue
) >= 0
1162 && (STORE_FLAG_VALUE
== 1
1163 || if_info
->branch_cost
>= 2))
1165 else if (itrue
== 0 && exact_log2 (ifalse
) >= 0 && can_reverse
1166 && (STORE_FLAG_VALUE
== 1 || if_info
->branch_cost
>= 2))
1167 normalize
= 1, reversep
= 1;
1168 else if (itrue
== -1
1169 && (STORE_FLAG_VALUE
== -1
1170 || if_info
->branch_cost
>= 2))
1172 else if (ifalse
== -1 && can_reverse
1173 && (STORE_FLAG_VALUE
== -1 || if_info
->branch_cost
>= 2))
1174 normalize
= -1, reversep
= 1;
1175 else if ((if_info
->branch_cost
>= 2 && STORE_FLAG_VALUE
== -1)
1176 || if_info
->branch_cost
>= 3)
1183 tmp
= itrue
; itrue
= ifalse
; ifalse
= tmp
;
1184 diff
= trunc_int_for_mode (-(unsigned HOST_WIDE_INT
) diff
, mode
);
1188 target
= noce_emit_store_flag (if_info
, if_info
->x
, reversep
, normalize
);
1195 /* if (test) x = 3; else x = 4;
1196 => x = 3 + (test == 0); */
1197 if (diff
== STORE_FLAG_VALUE
|| diff
== -STORE_FLAG_VALUE
)
1199 target
= expand_simple_binop (mode
,
1200 (diff
== STORE_FLAG_VALUE
1202 gen_int_mode (ifalse
, mode
), target
,
1203 if_info
->x
, 0, OPTAB_WIDEN
);
1206 /* if (test) x = 8; else x = 0;
1207 => x = (test != 0) << 3; */
1208 else if (ifalse
== 0 && (tmp
= exact_log2 (itrue
)) >= 0)
1210 target
= expand_simple_binop (mode
, ASHIFT
,
1211 target
, GEN_INT (tmp
), if_info
->x
, 0,
1215 /* if (test) x = -1; else x = b;
1216 => x = -(test != 0) | b; */
1217 else if (itrue
== -1)
1219 target
= expand_simple_binop (mode
, IOR
,
1220 target
, gen_int_mode (ifalse
, mode
),
1221 if_info
->x
, 0, OPTAB_WIDEN
);
1224 /* if (test) x = a; else x = b;
1225 => x = (-(test != 0) & (b - a)) + a; */
1228 target
= expand_simple_binop (mode
, AND
,
1229 target
, gen_int_mode (diff
, mode
),
1230 if_info
->x
, 0, OPTAB_WIDEN
);
1232 target
= expand_simple_binop (mode
, PLUS
,
1233 target
, gen_int_mode (ifalse
, mode
),
1234 if_info
->x
, 0, OPTAB_WIDEN
);
1243 if (target
!= if_info
->x
)
1244 noce_emit_move_insn (if_info
->x
, target
);
1246 seq
= end_ifcvt_sequence (if_info
);
1250 emit_insn_before_setloc (seq
, if_info
->jump
,
1251 INSN_LOCATION (if_info
->insn_a
));
1258 /* Convert "if (test) foo++" into "foo += (test != 0)", and
1259 similarly for "foo--". */
1262 noce_try_addcc (struct noce_if_info
*if_info
)
1265 int subtract
, normalize
;
1267 if (GET_CODE (if_info
->a
) == PLUS
1268 && rtx_equal_p (XEXP (if_info
->a
, 0), if_info
->b
)
1269 && (reversed_comparison_code (if_info
->cond
, if_info
->jump
)
1272 rtx cond
= if_info
->cond
;
1273 enum rtx_code code
= reversed_comparison_code (cond
, if_info
->jump
);
1275 /* First try to use addcc pattern. */
1276 if (general_operand (XEXP (cond
, 0), VOIDmode
)
1277 && general_operand (XEXP (cond
, 1), VOIDmode
))
1280 target
= emit_conditional_add (if_info
->x
, code
,
1285 XEXP (if_info
->a
, 1),
1286 GET_MODE (if_info
->x
),
1287 (code
== LTU
|| code
== GEU
1288 || code
== LEU
|| code
== GTU
));
1291 if (target
!= if_info
->x
)
1292 noce_emit_move_insn (if_info
->x
, target
);
1294 seq
= end_ifcvt_sequence (if_info
);
1298 emit_insn_before_setloc (seq
, if_info
->jump
,
1299 INSN_LOCATION (if_info
->insn_a
));
1305 /* If that fails, construct conditional increment or decrement using
1307 if (if_info
->branch_cost
>= 2
1308 && (XEXP (if_info
->a
, 1) == const1_rtx
1309 || XEXP (if_info
->a
, 1) == constm1_rtx
))
1312 if (STORE_FLAG_VALUE
== INTVAL (XEXP (if_info
->a
, 1)))
1313 subtract
= 0, normalize
= 0;
1314 else if (-STORE_FLAG_VALUE
== INTVAL (XEXP (if_info
->a
, 1)))
1315 subtract
= 1, normalize
= 0;
1317 subtract
= 0, normalize
= INTVAL (XEXP (if_info
->a
, 1));
1320 target
= noce_emit_store_flag (if_info
,
1321 gen_reg_rtx (GET_MODE (if_info
->x
)),
1325 target
= expand_simple_binop (GET_MODE (if_info
->x
),
1326 subtract
? MINUS
: PLUS
,
1327 if_info
->b
, target
, if_info
->x
,
1331 if (target
!= if_info
->x
)
1332 noce_emit_move_insn (if_info
->x
, target
);
1334 seq
= end_ifcvt_sequence (if_info
);
1338 emit_insn_before_setloc (seq
, if_info
->jump
,
1339 INSN_LOCATION (if_info
->insn_a
));
1349 /* Convert "if (test) x = 0;" to "x &= -(test == 0);" */
1352 noce_try_store_flag_mask (struct noce_if_info
*if_info
)
1358 if ((if_info
->branch_cost
>= 2
1359 || STORE_FLAG_VALUE
== -1)
1360 && ((if_info
->a
== const0_rtx
1361 && rtx_equal_p (if_info
->b
, if_info
->x
))
1362 || ((reversep
= (reversed_comparison_code (if_info
->cond
,
1365 && if_info
->b
== const0_rtx
1366 && rtx_equal_p (if_info
->a
, if_info
->x
))))
1369 target
= noce_emit_store_flag (if_info
,
1370 gen_reg_rtx (GET_MODE (if_info
->x
)),
1373 target
= expand_simple_binop (GET_MODE (if_info
->x
), AND
,
1375 target
, if_info
->x
, 0,
1380 if (target
!= if_info
->x
)
1381 noce_emit_move_insn (if_info
->x
, target
);
1383 seq
= end_ifcvt_sequence (if_info
);
1387 emit_insn_before_setloc (seq
, if_info
->jump
,
1388 INSN_LOCATION (if_info
->insn_a
));
1398 /* Helper function for noce_try_cmove and noce_try_cmove_arith. */
1401 noce_emit_cmove (struct noce_if_info
*if_info
, rtx x
, enum rtx_code code
,
1402 rtx cmp_a
, rtx cmp_b
, rtx vfalse
, rtx vtrue
)
1404 rtx target ATTRIBUTE_UNUSED
;
1405 int unsignedp ATTRIBUTE_UNUSED
;
1407 /* If earliest == jump, try to build the cmove insn directly.
1408 This is helpful when combine has created some complex condition
1409 (like for alpha's cmovlbs) that we can't hope to regenerate
1410 through the normal interface. */
1412 if (if_info
->cond_earliest
== if_info
->jump
)
1416 tmp
= gen_rtx_fmt_ee (code
, GET_MODE (if_info
->cond
), cmp_a
, cmp_b
);
1417 tmp
= gen_rtx_IF_THEN_ELSE (GET_MODE (x
), tmp
, vtrue
, vfalse
);
1418 tmp
= gen_rtx_SET (VOIDmode
, x
, tmp
);
1421 tmp
= emit_insn (tmp
);
1423 if (recog_memoized (tmp
) >= 0)
1435 /* Don't even try if the comparison operands are weird. */
1436 if (! general_operand (cmp_a
, GET_MODE (cmp_a
))
1437 || ! general_operand (cmp_b
, GET_MODE (cmp_b
)))
1440 #if HAVE_conditional_move
1441 unsignedp
= (code
== LTU
|| code
== GEU
1442 || code
== LEU
|| code
== GTU
);
1444 target
= emit_conditional_move (x
, code
, cmp_a
, cmp_b
, VOIDmode
,
1445 vtrue
, vfalse
, GET_MODE (x
),
1450 /* We might be faced with a situation like:
1453 vtrue = (subreg:M (reg:N VTRUE) BYTE)
1454 vfalse = (subreg:M (reg:N VFALSE) BYTE)
1456 We can't do a conditional move in mode M, but it's possible that we
1457 could do a conditional move in mode N instead and take a subreg of
1460 If we can't create new pseudos, though, don't bother. */
1461 if (reload_completed
)
1464 if (GET_CODE (vtrue
) == SUBREG
&& GET_CODE (vfalse
) == SUBREG
)
1466 rtx reg_vtrue
= SUBREG_REG (vtrue
);
1467 rtx reg_vfalse
= SUBREG_REG (vfalse
);
1468 unsigned int byte_vtrue
= SUBREG_BYTE (vtrue
);
1469 unsigned int byte_vfalse
= SUBREG_BYTE (vfalse
);
1470 rtx promoted_target
;
1472 if (GET_MODE (reg_vtrue
) != GET_MODE (reg_vfalse
)
1473 || byte_vtrue
!= byte_vfalse
1474 || (SUBREG_PROMOTED_VAR_P (vtrue
)
1475 != SUBREG_PROMOTED_VAR_P (vfalse
))
1476 || (SUBREG_PROMOTED_UNSIGNED_P (vtrue
)
1477 != SUBREG_PROMOTED_UNSIGNED_P (vfalse
)))
1480 promoted_target
= gen_reg_rtx (GET_MODE (reg_vtrue
));
1482 target
= emit_conditional_move (promoted_target
, code
, cmp_a
, cmp_b
,
1483 VOIDmode
, reg_vtrue
, reg_vfalse
,
1484 GET_MODE (reg_vtrue
), unsignedp
);
1485 /* Nope, couldn't do it in that mode either. */
1489 target
= gen_rtx_SUBREG (GET_MODE (vtrue
), promoted_target
, byte_vtrue
);
1490 SUBREG_PROMOTED_VAR_P (target
) = SUBREG_PROMOTED_VAR_P (vtrue
);
1491 SUBREG_PROMOTED_UNSIGNED_SET (target
, SUBREG_PROMOTED_UNSIGNED_P (vtrue
));
1492 emit_move_insn (x
, target
);
1498 /* We'll never get here, as noce_process_if_block doesn't call the
1499 functions involved. Ifdef code, however, should be discouraged
1500 because it leads to typos in the code not selected. However,
1501 emit_conditional_move won't exist either. */
1506 /* Try only simple constants and registers here. More complex cases
1507 are handled in noce_try_cmove_arith after noce_try_store_flag_arith
1508 has had a go at it. */
1511 noce_try_cmove (struct noce_if_info
*if_info
)
1516 if ((CONSTANT_P (if_info
->a
) || register_operand (if_info
->a
, VOIDmode
))
1517 && (CONSTANT_P (if_info
->b
) || register_operand (if_info
->b
, VOIDmode
)))
1521 code
= GET_CODE (if_info
->cond
);
1522 target
= noce_emit_cmove (if_info
, if_info
->x
, code
,
1523 XEXP (if_info
->cond
, 0),
1524 XEXP (if_info
->cond
, 1),
1525 if_info
->a
, if_info
->b
);
1529 if (target
!= if_info
->x
)
1530 noce_emit_move_insn (if_info
->x
, target
);
1532 seq
= end_ifcvt_sequence (if_info
);
1536 emit_insn_before_setloc (seq
, if_info
->jump
,
1537 INSN_LOCATION (if_info
->insn_a
));
1550 /* Try more complex cases involving conditional_move. */
1553 noce_try_cmove_arith (struct noce_if_info
*if_info
)
1565 /* A conditional move from two memory sources is equivalent to a
1566 conditional on their addresses followed by a load. Don't do this
1567 early because it'll screw alias analysis. Note that we've
1568 already checked for no side effects. */
1569 /* ??? FIXME: Magic number 5. */
1570 if (cse_not_expected
1571 && MEM_P (a
) && MEM_P (b
)
1572 && MEM_ADDR_SPACE (a
) == MEM_ADDR_SPACE (b
)
1573 && if_info
->branch_cost
>= 5)
1575 enum machine_mode address_mode
= get_address_mode (a
);
1579 x
= gen_reg_rtx (address_mode
);
1583 /* ??? We could handle this if we knew that a load from A or B could
1584 not trap or fault. This is also true if we've already loaded
1585 from the address along the path from ENTRY. */
1586 else if (may_trap_or_fault_p (a
) || may_trap_or_fault_p (b
))
1589 /* if (test) x = a + b; else x = c - d;
1596 code
= GET_CODE (if_info
->cond
);
1597 insn_a
= if_info
->insn_a
;
1598 insn_b
= if_info
->insn_b
;
1600 /* Total insn_rtx_cost should be smaller than branch cost. Exit
1601 if insn_rtx_cost can't be estimated. */
1605 = insn_rtx_cost (PATTERN (insn_a
),
1606 optimize_bb_for_speed_p (BLOCK_FOR_INSN (insn_a
)));
1607 if (insn_cost
== 0 || insn_cost
> COSTS_N_INSNS (if_info
->branch_cost
))
1616 += insn_rtx_cost (PATTERN (insn_b
),
1617 optimize_bb_for_speed_p (BLOCK_FOR_INSN (insn_b
)));
1618 if (insn_cost
== 0 || insn_cost
> COSTS_N_INSNS (if_info
->branch_cost
))
1622 /* Possibly rearrange operands to make things come out more natural. */
1623 if (reversed_comparison_code (if_info
->cond
, if_info
->jump
) != UNKNOWN
)
1626 if (rtx_equal_p (b
, x
))
1628 else if (general_operand (b
, GET_MODE (b
)))
1633 code
= reversed_comparison_code (if_info
->cond
, if_info
->jump
);
1634 tmp
= a
, a
= b
, b
= tmp
;
1635 tmp
= insn_a
, insn_a
= insn_b
, insn_b
= tmp
;
1644 /* If either operand is complex, load it into a register first.
1645 The best way to do this is to copy the original insn. In this
1646 way we preserve any clobbers etc that the insn may have had.
1647 This is of course not possible in the IS_MEM case. */
1648 if (! general_operand (a
, GET_MODE (a
)))
1654 tmp
= gen_reg_rtx (GET_MODE (a
));
1655 tmp
= emit_insn (gen_rtx_SET (VOIDmode
, tmp
, a
));
1658 goto end_seq_and_fail
;
1661 a
= gen_reg_rtx (GET_MODE (a
));
1662 tmp
= copy_rtx (insn_a
);
1663 set
= single_set (tmp
);
1665 tmp
= emit_insn (PATTERN (tmp
));
1667 if (recog_memoized (tmp
) < 0)
1668 goto end_seq_and_fail
;
1670 if (! general_operand (b
, GET_MODE (b
)))
1676 tmp
= gen_reg_rtx (GET_MODE (b
));
1677 tmp
= gen_rtx_SET (VOIDmode
, tmp
, b
);
1680 goto end_seq_and_fail
;
1683 b
= gen_reg_rtx (GET_MODE (b
));
1684 tmp
= copy_rtx (insn_b
);
1685 set
= single_set (tmp
);
1687 tmp
= PATTERN (tmp
);
1690 /* If insn to set up A clobbers any registers B depends on, try to
1691 swap insn that sets up A with the one that sets up B. If even
1692 that doesn't help, punt. */
1693 last
= get_last_insn ();
1694 if (last
&& modified_in_p (orig_b
, last
))
1696 tmp
= emit_insn_before (tmp
, get_insns ());
1697 if (modified_in_p (orig_a
, tmp
))
1698 goto end_seq_and_fail
;
1701 tmp
= emit_insn (tmp
);
1703 if (recog_memoized (tmp
) < 0)
1704 goto end_seq_and_fail
;
1707 target
= noce_emit_cmove (if_info
, x
, code
, XEXP (if_info
->cond
, 0),
1708 XEXP (if_info
->cond
, 1), a
, b
);
1711 goto end_seq_and_fail
;
1713 /* If we're handling a memory for above, emit the load now. */
1716 tmp
= gen_rtx_MEM (GET_MODE (if_info
->x
), target
);
1718 /* Copy over flags as appropriate. */
1719 if (MEM_VOLATILE_P (if_info
->a
) || MEM_VOLATILE_P (if_info
->b
))
1720 MEM_VOLATILE_P (tmp
) = 1;
1721 if (MEM_ALIAS_SET (if_info
->a
) == MEM_ALIAS_SET (if_info
->b
))
1722 set_mem_alias_set (tmp
, MEM_ALIAS_SET (if_info
->a
));
1724 MIN (MEM_ALIGN (if_info
->a
), MEM_ALIGN (if_info
->b
)));
1726 gcc_assert (MEM_ADDR_SPACE (if_info
->a
) == MEM_ADDR_SPACE (if_info
->b
));
1727 set_mem_addr_space (tmp
, MEM_ADDR_SPACE (if_info
->a
));
1729 noce_emit_move_insn (if_info
->x
, tmp
);
1731 else if (target
!= x
)
1732 noce_emit_move_insn (x
, target
);
1734 tmp
= end_ifcvt_sequence (if_info
);
1738 emit_insn_before_setloc (tmp
, if_info
->jump
, INSN_LOCATION (if_info
->insn_a
));
1746 /* For most cases, the simplified condition we found is the best
1747 choice, but this is not the case for the min/max/abs transforms.
1748 For these we wish to know that it is A or B in the condition. */
1751 noce_get_alt_condition (struct noce_if_info
*if_info
, rtx target
,
1754 rtx cond
, set
, insn
;
1757 /* If target is already mentioned in the known condition, return it. */
1758 if (reg_mentioned_p (target
, if_info
->cond
))
1760 *earliest
= if_info
->cond_earliest
;
1761 return if_info
->cond
;
1764 set
= pc_set (if_info
->jump
);
1765 cond
= XEXP (SET_SRC (set
), 0);
1767 = GET_CODE (XEXP (SET_SRC (set
), 2)) == LABEL_REF
1768 && XEXP (XEXP (SET_SRC (set
), 2), 0) == JUMP_LABEL (if_info
->jump
);
1769 if (if_info
->then_else_reversed
)
1772 /* If we're looking for a constant, try to make the conditional
1773 have that constant in it. There are two reasons why it may
1774 not have the constant we want:
1776 1. GCC may have needed to put the constant in a register, because
1777 the target can't compare directly against that constant. For
1778 this case, we look for a SET immediately before the comparison
1779 that puts a constant in that register.
1781 2. GCC may have canonicalized the conditional, for example
1782 replacing "if x < 4" with "if x <= 3". We can undo that (or
1783 make equivalent types of changes) to get the constants we need
1784 if they're off by one in the right direction. */
1786 if (CONST_INT_P (target
))
1788 enum rtx_code code
= GET_CODE (if_info
->cond
);
1789 rtx op_a
= XEXP (if_info
->cond
, 0);
1790 rtx op_b
= XEXP (if_info
->cond
, 1);
1793 /* First, look to see if we put a constant in a register. */
1794 prev_insn
= prev_nonnote_insn (if_info
->cond_earliest
);
1796 && BLOCK_FOR_INSN (prev_insn
)
1797 == BLOCK_FOR_INSN (if_info
->cond_earliest
)
1798 && INSN_P (prev_insn
)
1799 && GET_CODE (PATTERN (prev_insn
)) == SET
)
1801 rtx src
= find_reg_equal_equiv_note (prev_insn
);
1803 src
= SET_SRC (PATTERN (prev_insn
));
1804 if (CONST_INT_P (src
))
1806 if (rtx_equal_p (op_a
, SET_DEST (PATTERN (prev_insn
))))
1808 else if (rtx_equal_p (op_b
, SET_DEST (PATTERN (prev_insn
))))
1811 if (CONST_INT_P (op_a
))
1816 code
= swap_condition (code
);
1821 /* Now, look to see if we can get the right constant by
1822 adjusting the conditional. */
1823 if (CONST_INT_P (op_b
))
1825 HOST_WIDE_INT desired_val
= INTVAL (target
);
1826 HOST_WIDE_INT actual_val
= INTVAL (op_b
);
1831 if (actual_val
== desired_val
+ 1)
1834 op_b
= GEN_INT (desired_val
);
1838 if (actual_val
== desired_val
- 1)
1841 op_b
= GEN_INT (desired_val
);
1845 if (actual_val
== desired_val
- 1)
1848 op_b
= GEN_INT (desired_val
);
1852 if (actual_val
== desired_val
+ 1)
1855 op_b
= GEN_INT (desired_val
);
1863 /* If we made any changes, generate a new conditional that is
1864 equivalent to what we started with, but has the right
1866 if (code
!= GET_CODE (if_info
->cond
)
1867 || op_a
!= XEXP (if_info
->cond
, 0)
1868 || op_b
!= XEXP (if_info
->cond
, 1))
1870 cond
= gen_rtx_fmt_ee (code
, GET_MODE (cond
), op_a
, op_b
);
1871 *earliest
= if_info
->cond_earliest
;
1876 cond
= canonicalize_condition (if_info
->jump
, cond
, reverse
,
1877 earliest
, target
, false, true);
1878 if (! cond
|| ! reg_mentioned_p (target
, cond
))
1881 /* We almost certainly searched back to a different place.
1882 Need to re-verify correct lifetimes. */
1884 /* X may not be mentioned in the range (cond_earliest, jump]. */
1885 for (insn
= if_info
->jump
; insn
!= *earliest
; insn
= PREV_INSN (insn
))
1886 if (INSN_P (insn
) && reg_overlap_mentioned_p (if_info
->x
, PATTERN (insn
)))
1889 /* A and B may not be modified in the range [cond_earliest, jump). */
1890 for (insn
= *earliest
; insn
!= if_info
->jump
; insn
= NEXT_INSN (insn
))
1892 && (modified_in_p (if_info
->a
, insn
)
1893 || modified_in_p (if_info
->b
, insn
)))
1899 /* Convert "if (a < b) x = a; else x = b;" to "x = min(a, b);", etc. */
1902 noce_try_minmax (struct noce_if_info
*if_info
)
1904 rtx cond
, earliest
, target
, seq
;
1905 enum rtx_code code
, op
;
1908 /* ??? Reject modes with NaNs or signed zeros since we don't know how
1909 they will be resolved with an SMIN/SMAX. It wouldn't be too hard
1910 to get the target to tell us... */
1911 if (HONOR_SIGNED_ZEROS (GET_MODE (if_info
->x
))
1912 || HONOR_NANS (GET_MODE (if_info
->x
)))
1915 cond
= noce_get_alt_condition (if_info
, if_info
->a
, &earliest
);
1919 /* Verify the condition is of the form we expect, and canonicalize
1920 the comparison code. */
1921 code
= GET_CODE (cond
);
1922 if (rtx_equal_p (XEXP (cond
, 0), if_info
->a
))
1924 if (! rtx_equal_p (XEXP (cond
, 1), if_info
->b
))
1927 else if (rtx_equal_p (XEXP (cond
, 1), if_info
->a
))
1929 if (! rtx_equal_p (XEXP (cond
, 0), if_info
->b
))
1931 code
= swap_condition (code
);
1936 /* Determine what sort of operation this is. Note that the code is for
1937 a taken branch, so the code->operation mapping appears backwards. */
1970 target
= expand_simple_binop (GET_MODE (if_info
->x
), op
,
1971 if_info
->a
, if_info
->b
,
1972 if_info
->x
, unsignedp
, OPTAB_WIDEN
);
1978 if (target
!= if_info
->x
)
1979 noce_emit_move_insn (if_info
->x
, target
);
1981 seq
= end_ifcvt_sequence (if_info
);
1985 emit_insn_before_setloc (seq
, if_info
->jump
, INSN_LOCATION (if_info
->insn_a
));
1986 if_info
->cond
= cond
;
1987 if_info
->cond_earliest
= earliest
;
1992 /* Convert "if (a < 0) x = -a; else x = a;" to "x = abs(a);",
1993 "if (a < 0) x = ~a; else x = a;" to "x = one_cmpl_abs(a);",
1997 noce_try_abs (struct noce_if_info
*if_info
)
1999 rtx cond
, earliest
, target
, seq
, a
, b
, c
;
2001 bool one_cmpl
= false;
2003 /* Reject modes with signed zeros. */
2004 if (HONOR_SIGNED_ZEROS (GET_MODE (if_info
->x
)))
2007 /* Recognize A and B as constituting an ABS or NABS. The canonical
2008 form is a branch around the negation, taken when the object is the
2009 first operand of a comparison against 0 that evaluates to true. */
2012 if (GET_CODE (a
) == NEG
&& rtx_equal_p (XEXP (a
, 0), b
))
2014 else if (GET_CODE (b
) == NEG
&& rtx_equal_p (XEXP (b
, 0), a
))
2016 c
= a
; a
= b
; b
= c
;
2019 else if (GET_CODE (a
) == NOT
&& rtx_equal_p (XEXP (a
, 0), b
))
2024 else if (GET_CODE (b
) == NOT
&& rtx_equal_p (XEXP (b
, 0), a
))
2026 c
= a
; a
= b
; b
= c
;
2033 cond
= noce_get_alt_condition (if_info
, b
, &earliest
);
2037 /* Verify the condition is of the form we expect. */
2038 if (rtx_equal_p (XEXP (cond
, 0), b
))
2040 else if (rtx_equal_p (XEXP (cond
, 1), b
))
2048 /* Verify that C is zero. Search one step backward for a
2049 REG_EQUAL note or a simple source if necessary. */
2052 rtx set
, insn
= prev_nonnote_insn (earliest
);
2054 && BLOCK_FOR_INSN (insn
) == BLOCK_FOR_INSN (earliest
)
2055 && (set
= single_set (insn
))
2056 && rtx_equal_p (SET_DEST (set
), c
))
2058 rtx note
= find_reg_equal_equiv_note (insn
);
2068 && GET_CODE (XEXP (c
, 0)) == SYMBOL_REF
2069 && CONSTANT_POOL_ADDRESS_P (XEXP (c
, 0)))
2070 c
= get_pool_constant (XEXP (c
, 0));
2072 /* Work around funny ideas get_condition has wrt canonicalization.
2073 Note that these rtx constants are known to be CONST_INT, and
2074 therefore imply integer comparisons. */
2075 if (c
== constm1_rtx
&& GET_CODE (cond
) == GT
)
2077 else if (c
== const1_rtx
&& GET_CODE (cond
) == LT
)
2079 else if (c
!= CONST0_RTX (GET_MODE (b
)))
2082 /* Determine what sort of operation this is. */
2083 switch (GET_CODE (cond
))
2102 target
= expand_one_cmpl_abs_nojump (GET_MODE (if_info
->x
), b
,
2105 target
= expand_abs_nojump (GET_MODE (if_info
->x
), b
, if_info
->x
, 1);
2107 /* ??? It's a quandary whether cmove would be better here, especially
2108 for integers. Perhaps combine will clean things up. */
2109 if (target
&& negate
)
2112 target
= expand_simple_unop (GET_MODE (target
), NOT
, target
,
2115 target
= expand_simple_unop (GET_MODE (target
), NEG
, target
,
2125 if (target
!= if_info
->x
)
2126 noce_emit_move_insn (if_info
->x
, target
);
2128 seq
= end_ifcvt_sequence (if_info
);
2132 emit_insn_before_setloc (seq
, if_info
->jump
, INSN_LOCATION (if_info
->insn_a
));
2133 if_info
->cond
= cond
;
2134 if_info
->cond_earliest
= earliest
;
2139 /* Convert "if (m < 0) x = b; else x = 0;" to "x = (m >> C) & b;". */
2142 noce_try_sign_mask (struct noce_if_info
*if_info
)
2144 rtx cond
, t
, m
, c
, seq
;
2145 enum machine_mode mode
;
2147 bool t_unconditional
;
2149 cond
= if_info
->cond
;
2150 code
= GET_CODE (cond
);
2155 if (if_info
->a
== const0_rtx
)
2157 if ((code
== LT
&& c
== const0_rtx
)
2158 || (code
== LE
&& c
== constm1_rtx
))
2161 else if (if_info
->b
== const0_rtx
)
2163 if ((code
== GE
&& c
== const0_rtx
)
2164 || (code
== GT
&& c
== constm1_rtx
))
2168 if (! t
|| side_effects_p (t
))
2171 /* We currently don't handle different modes. */
2172 mode
= GET_MODE (t
);
2173 if (GET_MODE (m
) != mode
)
2176 /* This is only profitable if T is unconditionally executed/evaluated in the
2177 original insn sequence or T is cheap. The former happens if B is the
2178 non-zero (T) value and if INSN_B was taken from TEST_BB, or there was no
2179 INSN_B which can happen for e.g. conditional stores to memory. For the
2180 cost computation use the block TEST_BB where the evaluation will end up
2181 after the transformation. */
2184 && (if_info
->insn_b
== NULL_RTX
2185 || BLOCK_FOR_INSN (if_info
->insn_b
) == if_info
->test_bb
));
2186 if (!(t_unconditional
2187 || (set_src_cost (t
, optimize_bb_for_speed_p (if_info
->test_bb
))
2188 < COSTS_N_INSNS (2))))
2192 /* Use emit_store_flag to generate "m < 0 ? -1 : 0" instead of expanding
2193 "(signed) m >> 31" directly. This benefits targets with specialized
2194 insns to obtain the signmask, but still uses ashr_optab otherwise. */
2195 m
= emit_store_flag (gen_reg_rtx (mode
), LT
, m
, const0_rtx
, mode
, 0, -1);
2196 t
= m
? expand_binop (mode
, and_optab
, m
, t
, NULL_RTX
, 0, OPTAB_DIRECT
)
2205 noce_emit_move_insn (if_info
->x
, t
);
2207 seq
= end_ifcvt_sequence (if_info
);
2211 emit_insn_before_setloc (seq
, if_info
->jump
, INSN_LOCATION (if_info
->insn_a
));
2216 /* Optimize away "if (x & C) x |= C" and similar bit manipulation
2220 noce_try_bitop (struct noce_if_info
*if_info
)
2222 rtx cond
, x
, a
, result
, seq
;
2223 enum machine_mode mode
;
2228 cond
= if_info
->cond
;
2229 code
= GET_CODE (cond
);
2231 /* Check for no else condition. */
2232 if (! rtx_equal_p (x
, if_info
->b
))
2235 /* Check for a suitable condition. */
2236 if (code
!= NE
&& code
!= EQ
)
2238 if (XEXP (cond
, 1) != const0_rtx
)
2240 cond
= XEXP (cond
, 0);
2242 /* ??? We could also handle AND here. */
2243 if (GET_CODE (cond
) == ZERO_EXTRACT
)
2245 if (XEXP (cond
, 1) != const1_rtx
2246 || !CONST_INT_P (XEXP (cond
, 2))
2247 || ! rtx_equal_p (x
, XEXP (cond
, 0)))
2249 bitnum
= INTVAL (XEXP (cond
, 2));
2250 mode
= GET_MODE (x
);
2251 if (BITS_BIG_ENDIAN
)
2252 bitnum
= GET_MODE_BITSIZE (mode
) - 1 - bitnum
;
2253 if (bitnum
< 0 || bitnum
>= HOST_BITS_PER_WIDE_INT
)
2260 if (GET_CODE (a
) == IOR
|| GET_CODE (a
) == XOR
)
2262 /* Check for "if (X & C) x = x op C". */
2263 if (! rtx_equal_p (x
, XEXP (a
, 0))
2264 || !CONST_INT_P (XEXP (a
, 1))
2265 || (INTVAL (XEXP (a
, 1)) & GET_MODE_MASK (mode
))
2266 != (unsigned HOST_WIDE_INT
) 1 << bitnum
)
2269 /* if ((x & C) == 0) x |= C; is transformed to x |= C. */
2270 /* if ((x & C) != 0) x |= C; is transformed to nothing. */
2271 if (GET_CODE (a
) == IOR
)
2272 result
= (code
== NE
) ? a
: NULL_RTX
;
2273 else if (code
== NE
)
2275 /* if ((x & C) == 0) x ^= C; is transformed to x |= C. */
2276 result
= gen_int_mode ((HOST_WIDE_INT
) 1 << bitnum
, mode
);
2277 result
= simplify_gen_binary (IOR
, mode
, x
, result
);
2281 /* if ((x & C) != 0) x ^= C; is transformed to x &= ~C. */
2282 result
= gen_int_mode (~((HOST_WIDE_INT
) 1 << bitnum
), mode
);
2283 result
= simplify_gen_binary (AND
, mode
, x
, result
);
2286 else if (GET_CODE (a
) == AND
)
2288 /* Check for "if (X & C) x &= ~C". */
2289 if (! rtx_equal_p (x
, XEXP (a
, 0))
2290 || !CONST_INT_P (XEXP (a
, 1))
2291 || (INTVAL (XEXP (a
, 1)) & GET_MODE_MASK (mode
))
2292 != (~((HOST_WIDE_INT
) 1 << bitnum
) & GET_MODE_MASK (mode
)))
2295 /* if ((x & C) == 0) x &= ~C; is transformed to nothing. */
2296 /* if ((x & C) != 0) x &= ~C; is transformed to x &= ~C. */
2297 result
= (code
== EQ
) ? a
: NULL_RTX
;
2305 noce_emit_move_insn (x
, result
);
2306 seq
= end_ifcvt_sequence (if_info
);
2310 emit_insn_before_setloc (seq
, if_info
->jump
,
2311 INSN_LOCATION (if_info
->insn_a
));
2317 /* Similar to get_condition, only the resulting condition must be
2318 valid at JUMP, instead of at EARLIEST.
2320 If THEN_ELSE_REVERSED is true, the fallthrough does not go to the
2321 THEN block of the caller, and we have to reverse the condition. */
2324 noce_get_condition (rtx jump
, rtx
*earliest
, bool then_else_reversed
)
2329 if (! any_condjump_p (jump
))
2332 set
= pc_set (jump
);
2334 /* If this branches to JUMP_LABEL when the condition is false,
2335 reverse the condition. */
2336 reverse
= (GET_CODE (XEXP (SET_SRC (set
), 2)) == LABEL_REF
2337 && XEXP (XEXP (SET_SRC (set
), 2), 0) == JUMP_LABEL (jump
));
2339 /* We may have to reverse because the caller's if block is not canonical,
2340 i.e. the THEN block isn't the fallthrough block for the TEST block
2341 (see find_if_header). */
2342 if (then_else_reversed
)
2345 /* If the condition variable is a register and is MODE_INT, accept it. */
2347 cond
= XEXP (SET_SRC (set
), 0);
2348 tmp
= XEXP (cond
, 0);
2349 if (REG_P (tmp
) && GET_MODE_CLASS (GET_MODE (tmp
)) == MODE_INT
2350 && (GET_MODE (tmp
) != BImode
2351 || !targetm
.small_register_classes_for_mode_p (BImode
)))
2356 cond
= gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond
)),
2357 GET_MODE (cond
), tmp
, XEXP (cond
, 1));
2361 /* Otherwise, fall back on canonicalize_condition to do the dirty
2362 work of manipulating MODE_CC values and COMPARE rtx codes. */
2363 tmp
= canonicalize_condition (jump
, cond
, reverse
, earliest
,
2364 NULL_RTX
, false, true);
2366 /* We don't handle side-effects in the condition, like handling
2367 REG_INC notes and making sure no duplicate conditions are emitted. */
2368 if (tmp
!= NULL_RTX
&& side_effects_p (tmp
))
2374 /* Return true if OP is ok for if-then-else processing. */
2377 noce_operand_ok (const_rtx op
)
2379 if (side_effects_p (op
))
2382 /* We special-case memories, so handle any of them with
2383 no address side effects. */
2385 return ! side_effects_p (XEXP (op
, 0));
2387 return ! may_trap_p (op
);
2390 /* Return true if a write into MEM may trap or fault. */
2393 noce_mem_write_may_trap_or_fault_p (const_rtx mem
)
2397 if (MEM_READONLY_P (mem
))
2400 if (may_trap_or_fault_p (mem
))
2403 addr
= XEXP (mem
, 0);
2405 /* Call target hook to avoid the effects of -fpic etc.... */
2406 addr
= targetm
.delegitimize_address (addr
);
2409 switch (GET_CODE (addr
))
2417 addr
= XEXP (addr
, 0);
2421 addr
= XEXP (addr
, 1);
2424 if (CONST_INT_P (XEXP (addr
, 1)))
2425 addr
= XEXP (addr
, 0);
2432 if (SYMBOL_REF_DECL (addr
)
2433 && decl_readonly_section (SYMBOL_REF_DECL (addr
), 0))
2443 /* Return whether we can use store speculation for MEM. TOP_BB is the
2444 basic block above the conditional block where we are considering
2445 doing the speculative store. We look for whether MEM is set
2446 unconditionally later in the function. */
2449 noce_can_store_speculate_p (basic_block top_bb
, const_rtx mem
)
2451 basic_block dominator
;
2453 for (dominator
= get_immediate_dominator (CDI_POST_DOMINATORS
, top_bb
);
2455 dominator
= get_immediate_dominator (CDI_POST_DOMINATORS
, dominator
))
2459 FOR_BB_INSNS (dominator
, insn
)
2461 /* If we see something that might be a memory barrier, we
2462 have to stop looking. Even if the MEM is set later in
2463 the function, we still don't want to set it
2464 unconditionally before the barrier. */
2466 && (volatile_insn_p (PATTERN (insn
))
2467 || (CALL_P (insn
) && (!RTL_CONST_CALL_P (insn
)))))
2470 if (memory_must_be_modified_in_insn_p (mem
, insn
))
2472 if (modified_in_p (XEXP (mem
, 0), insn
))
2481 /* Given a simple IF-THEN-JOIN or IF-THEN-ELSE-JOIN block, attempt to convert
2482 it without using conditional execution. Return TRUE if we were successful
2483 at converting the block. */
2486 noce_process_if_block (struct noce_if_info
*if_info
)
2488 basic_block test_bb
= if_info
->test_bb
; /* test block */
2489 basic_block then_bb
= if_info
->then_bb
; /* THEN */
2490 basic_block else_bb
= if_info
->else_bb
; /* ELSE or NULL */
2491 basic_block join_bb
= if_info
->join_bb
; /* JOIN */
2492 rtx jump
= if_info
->jump
;
2493 rtx cond
= if_info
->cond
;
2496 rtx orig_x
, x
, a
, b
;
2498 /* We're looking for patterns of the form
2500 (1) if (...) x = a; else x = b;
2501 (2) x = b; if (...) x = a;
2502 (3) if (...) x = a; // as if with an initial x = x.
2504 The later patterns require jumps to be more expensive.
2506 ??? For future expansion, look for multiple X in such patterns. */
2508 /* Look for one of the potential sets. */
2509 insn_a
= first_active_insn (then_bb
);
2511 || insn_a
!= last_active_insn (then_bb
, FALSE
)
2512 || (set_a
= single_set (insn_a
)) == NULL_RTX
)
2515 x
= SET_DEST (set_a
);
2516 a
= SET_SRC (set_a
);
2518 /* Look for the other potential set. Make sure we've got equivalent
2520 /* ??? This is overconservative. Storing to two different mems is
2521 as easy as conditionally computing the address. Storing to a
2522 single mem merely requires a scratch memory to use as one of the
2523 destination addresses; often the memory immediately below the
2524 stack pointer is available for this. */
2528 insn_b
= first_active_insn (else_bb
);
2530 || insn_b
!= last_active_insn (else_bb
, FALSE
)
2531 || (set_b
= single_set (insn_b
)) == NULL_RTX
2532 || ! rtx_interchangeable_p (x
, SET_DEST (set_b
)))
2537 insn_b
= prev_nonnote_nondebug_insn (if_info
->cond_earliest
);
2538 /* We're going to be moving the evaluation of B down from above
2539 COND_EARLIEST to JUMP. Make sure the relevant data is still
2542 || BLOCK_FOR_INSN (insn_b
) != BLOCK_FOR_INSN (if_info
->cond_earliest
)
2543 || !NONJUMP_INSN_P (insn_b
)
2544 || (set_b
= single_set (insn_b
)) == NULL_RTX
2545 || ! rtx_interchangeable_p (x
, SET_DEST (set_b
))
2546 || ! noce_operand_ok (SET_SRC (set_b
))
2547 || reg_overlap_mentioned_p (x
, SET_SRC (set_b
))
2548 || modified_between_p (SET_SRC (set_b
), insn_b
, jump
)
2549 /* Avoid extending the lifetime of hard registers on small
2550 register class machines. */
2551 || (REG_P (SET_SRC (set_b
))
2552 && HARD_REGISTER_P (SET_SRC (set_b
))
2553 && targetm
.small_register_classes_for_mode_p
2554 (GET_MODE (SET_SRC (set_b
))))
2555 /* Likewise with X. In particular this can happen when
2556 noce_get_condition looks farther back in the instruction
2557 stream than one might expect. */
2558 || reg_overlap_mentioned_p (x
, cond
)
2559 || reg_overlap_mentioned_p (x
, a
)
2560 || modified_between_p (x
, insn_b
, jump
))
2561 insn_b
= set_b
= NULL_RTX
;
2564 /* If x has side effects then only the if-then-else form is safe to
2565 convert. But even in that case we would need to restore any notes
2566 (such as REG_INC) at then end. That can be tricky if
2567 noce_emit_move_insn expands to more than one insn, so disable the
2568 optimization entirely for now if there are side effects. */
2569 if (side_effects_p (x
))
2572 b
= (set_b
? SET_SRC (set_b
) : x
);
2574 /* Only operate on register destinations, and even then avoid extending
2575 the lifetime of hard registers on small register class machines. */
2578 || (HARD_REGISTER_P (x
)
2579 && targetm
.small_register_classes_for_mode_p (GET_MODE (x
))))
2581 if (GET_MODE (x
) == BLKmode
)
2584 if (GET_CODE (x
) == ZERO_EXTRACT
2585 && (!CONST_INT_P (XEXP (x
, 1))
2586 || !CONST_INT_P (XEXP (x
, 2))))
2589 x
= gen_reg_rtx (GET_MODE (GET_CODE (x
) == STRICT_LOW_PART
2590 ? XEXP (x
, 0) : x
));
2593 /* Don't operate on sources that may trap or are volatile. */
2594 if (! noce_operand_ok (a
) || ! noce_operand_ok (b
))
2598 /* Set up the info block for our subroutines. */
2599 if_info
->insn_a
= insn_a
;
2600 if_info
->insn_b
= insn_b
;
2605 /* Try optimizations in some approximation of a useful order. */
2606 /* ??? Should first look to see if X is live incoming at all. If it
2607 isn't, we don't need anything but an unconditional set. */
2609 /* Look and see if A and B are really the same. Avoid creating silly
2610 cmove constructs that no one will fix up later. */
2611 if (rtx_interchangeable_p (a
, b
))
2613 /* If we have an INSN_B, we don't have to create any new rtl. Just
2614 move the instruction that we already have. If we don't have an
2615 INSN_B, that means that A == X, and we've got a noop move. In
2616 that case don't do anything and let the code below delete INSN_A. */
2617 if (insn_b
&& else_bb
)
2621 if (else_bb
&& insn_b
== BB_END (else_bb
))
2622 BB_END (else_bb
) = PREV_INSN (insn_b
);
2623 reorder_insns (insn_b
, insn_b
, PREV_INSN (jump
));
2625 /* If there was a REG_EQUAL note, delete it since it may have been
2626 true due to this insn being after a jump. */
2627 if ((note
= find_reg_note (insn_b
, REG_EQUAL
, NULL_RTX
)) != 0)
2628 remove_note (insn_b
, note
);
2632 /* If we have "x = b; if (...) x = a;", and x has side-effects, then
2633 x must be executed twice. */
2634 else if (insn_b
&& side_effects_p (orig_x
))
2641 if (!set_b
&& MEM_P (orig_x
))
2643 /* Disallow the "if (...) x = a;" form (implicit "else x = x;")
2644 for optimizations if writing to x may trap or fault,
2645 i.e. it's a memory other than a static var or a stack slot,
2646 is misaligned on strict aligned machines or is read-only. If
2647 x is a read-only memory, then the program is valid only if we
2648 avoid the store into it. If there are stores on both the
2649 THEN and ELSE arms, then we can go ahead with the conversion;
2650 either the program is broken, or the condition is always
2651 false such that the other memory is selected. */
2652 if (noce_mem_write_may_trap_or_fault_p (orig_x
))
2655 /* Avoid store speculation: given "if (...) x = a" where x is a
2656 MEM, we only want to do the store if x is always set
2657 somewhere in the function. This avoids cases like
2658 if (pthread_mutex_trylock(mutex))
2660 where we only want global_variable to be changed if the mutex
2661 is held. FIXME: This should ideally be expressed directly in
2663 if (!noce_can_store_speculate_p (test_bb
, orig_x
))
2667 if (noce_try_move (if_info
))
2669 if (noce_try_store_flag (if_info
))
2671 if (noce_try_bitop (if_info
))
2673 if (noce_try_minmax (if_info
))
2675 if (noce_try_abs (if_info
))
2677 if (HAVE_conditional_move
2678 && noce_try_cmove (if_info
))
2680 if (! targetm
.have_conditional_execution ())
2682 if (noce_try_store_flag_constants (if_info
))
2684 if (noce_try_addcc (if_info
))
2686 if (noce_try_store_flag_mask (if_info
))
2688 if (HAVE_conditional_move
2689 && noce_try_cmove_arith (if_info
))
2691 if (noce_try_sign_mask (if_info
))
2695 if (!else_bb
&& set_b
)
2697 insn_b
= set_b
= NULL_RTX
;
2706 /* If we used a temporary, fix it up now. */
2712 noce_emit_move_insn (orig_x
, x
);
2714 set_used_flags (orig_x
);
2715 unshare_all_rtl_in_chain (seq
);
2718 emit_insn_before_setloc (seq
, BB_END (test_bb
), INSN_LOCATION (insn_a
));
2721 /* The original THEN and ELSE blocks may now be removed. The test block
2722 must now jump to the join block. If the test block and the join block
2723 can be merged, do so. */
2726 delete_basic_block (else_bb
);
2730 remove_edge (find_edge (test_bb
, join_bb
));
2732 remove_edge (find_edge (then_bb
, join_bb
));
2733 redirect_edge_and_branch_force (single_succ_edge (test_bb
), join_bb
);
2734 delete_basic_block (then_bb
);
2737 if (can_merge_blocks_p (test_bb
, join_bb
))
2739 merge_blocks (test_bb
, join_bb
);
2743 num_updated_if_blocks
++;
2747 /* Check whether a block is suitable for conditional move conversion.
2748 Every insn must be a simple set of a register to a constant or a
2749 register. For each assignment, store the value in the pointer map
2750 VALS, keyed indexed by register pointer, then store the register
2751 pointer in REGS. COND is the condition we will test. */
2754 check_cond_move_block (basic_block bb
,
2755 struct pointer_map_t
*vals
,
2761 /* We can only handle simple jumps at the end of the basic block.
2762 It is almost impossible to update the CFG otherwise. */
2764 if (JUMP_P (insn
) && !onlyjump_p (insn
))
2767 FOR_BB_INSNS (bb
, insn
)
2772 if (!NONDEBUG_INSN_P (insn
) || JUMP_P (insn
))
2774 set
= single_set (insn
);
2778 dest
= SET_DEST (set
);
2779 src
= SET_SRC (set
);
2781 || (HARD_REGISTER_P (dest
)
2782 && targetm
.small_register_classes_for_mode_p (GET_MODE (dest
))))
2785 if (!CONSTANT_P (src
) && !register_operand (src
, VOIDmode
))
2788 if (side_effects_p (src
) || side_effects_p (dest
))
2791 if (may_trap_p (src
) || may_trap_p (dest
))
2794 /* Don't try to handle this if the source register was
2795 modified earlier in the block. */
2797 && pointer_map_contains (vals
, src
))
2798 || (GET_CODE (src
) == SUBREG
&& REG_P (SUBREG_REG (src
))
2799 && pointer_map_contains (vals
, SUBREG_REG (src
))))
2802 /* Don't try to handle this if the destination register was
2803 modified earlier in the block. */
2804 if (pointer_map_contains (vals
, dest
))
2807 /* Don't try to handle this if the condition uses the
2808 destination register. */
2809 if (reg_overlap_mentioned_p (dest
, cond
))
2812 /* Don't try to handle this if the source register is modified
2813 later in the block. */
2814 if (!CONSTANT_P (src
)
2815 && modified_between_p (src
, insn
, NEXT_INSN (BB_END (bb
))))
2818 slot
= pointer_map_insert (vals
, (void *) dest
);
2819 *slot
= (void *) src
;
2821 regs
->safe_push (dest
);
2827 /* Given a basic block BB suitable for conditional move conversion,
2828 a condition COND, and pointer maps THEN_VALS and ELSE_VALS containing
2829 the register values depending on COND, emit the insns in the block as
2830 conditional moves. If ELSE_BLOCK is true, THEN_BB was already
2831 processed. The caller has started a sequence for the conversion.
2832 Return true if successful, false if something goes wrong. */
2835 cond_move_convert_if_block (struct noce_if_info
*if_infop
,
2836 basic_block bb
, rtx cond
,
2837 struct pointer_map_t
*then_vals
,
2838 struct pointer_map_t
*else_vals
,
2842 rtx insn
, cond_arg0
, cond_arg1
;
2844 code
= GET_CODE (cond
);
2845 cond_arg0
= XEXP (cond
, 0);
2846 cond_arg1
= XEXP (cond
, 1);
2848 FOR_BB_INSNS (bb
, insn
)
2850 rtx set
, target
, dest
, t
, e
;
2851 void **then_slot
, **else_slot
;
2853 /* ??? Maybe emit conditional debug insn? */
2854 if (!NONDEBUG_INSN_P (insn
) || JUMP_P (insn
))
2856 set
= single_set (insn
);
2857 gcc_assert (set
&& REG_P (SET_DEST (set
)));
2859 dest
= SET_DEST (set
);
2861 then_slot
= pointer_map_contains (then_vals
, dest
);
2862 else_slot
= pointer_map_contains (else_vals
, dest
);
2863 t
= then_slot
? (rtx
) *then_slot
: NULL_RTX
;
2864 e
= else_slot
? (rtx
) *else_slot
: NULL_RTX
;
2868 /* If this register was set in the then block, we already
2869 handled this case there. */
2882 target
= noce_emit_cmove (if_infop
, dest
, code
, cond_arg0
, cond_arg1
,
2888 noce_emit_move_insn (dest
, target
);
2894 /* Given a simple IF-THEN-JOIN or IF-THEN-ELSE-JOIN block, attempt to convert
2895 it using only conditional moves. Return TRUE if we were successful at
2896 converting the block. */
2899 cond_move_process_if_block (struct noce_if_info
*if_info
)
2901 basic_block test_bb
= if_info
->test_bb
;
2902 basic_block then_bb
= if_info
->then_bb
;
2903 basic_block else_bb
= if_info
->else_bb
;
2904 basic_block join_bb
= if_info
->join_bb
;
2905 rtx jump
= if_info
->jump
;
2906 rtx cond
= if_info
->cond
;
2910 struct pointer_map_t
*then_vals
;
2911 struct pointer_map_t
*else_vals
;
2912 vec
<rtx
> then_regs
= vNULL
;
2913 vec
<rtx
> else_regs
= vNULL
;
2915 int success_p
= FALSE
;
2917 /* Build a mapping for each block to the value used for each
2919 then_vals
= pointer_map_create ();
2920 else_vals
= pointer_map_create ();
2922 /* Make sure the blocks are suitable. */
2923 if (!check_cond_move_block (then_bb
, then_vals
, &then_regs
, cond
)
2925 && !check_cond_move_block (else_bb
, else_vals
, &else_regs
, cond
)))
2928 /* Make sure the blocks can be used together. If the same register
2929 is set in both blocks, and is not set to a constant in both
2930 cases, then both blocks must set it to the same register. We
2931 have already verified that if it is set to a register, that the
2932 source register does not change after the assignment. Also count
2933 the number of registers set in only one of the blocks. */
2935 FOR_EACH_VEC_ELT (then_regs
, i
, reg
)
2937 void **then_slot
= pointer_map_contains (then_vals
, reg
);
2938 void **else_slot
= pointer_map_contains (else_vals
, reg
);
2940 gcc_checking_assert (then_slot
);
2945 rtx then_val
= (rtx
) *then_slot
;
2946 rtx else_val
= (rtx
) *else_slot
;
2947 if (!CONSTANT_P (then_val
) && !CONSTANT_P (else_val
)
2948 && !rtx_equal_p (then_val
, else_val
))
2953 /* Finish off c for MAX_CONDITIONAL_EXECUTE. */
2954 FOR_EACH_VEC_ELT (else_regs
, i
, reg
)
2956 gcc_checking_assert (pointer_map_contains (else_vals
, reg
));
2957 if (!pointer_map_contains (then_vals
, reg
))
2961 /* Make sure it is reasonable to convert this block. What matters
2962 is the number of assignments currently made in only one of the
2963 branches, since if we convert we are going to always execute
2965 if (c
> MAX_CONDITIONAL_EXECUTE
)
2968 /* Try to emit the conditional moves. First do the then block,
2969 then do anything left in the else blocks. */
2971 if (!cond_move_convert_if_block (if_info
, then_bb
, cond
,
2972 then_vals
, else_vals
, false)
2974 && !cond_move_convert_if_block (if_info
, else_bb
, cond
,
2975 then_vals
, else_vals
, true)))
2980 seq
= end_ifcvt_sequence (if_info
);
2984 loc_insn
= first_active_insn (then_bb
);
2987 loc_insn
= first_active_insn (else_bb
);
2988 gcc_assert (loc_insn
);
2990 emit_insn_before_setloc (seq
, jump
, INSN_LOCATION (loc_insn
));
2994 delete_basic_block (else_bb
);
2998 remove_edge (find_edge (test_bb
, join_bb
));
3000 remove_edge (find_edge (then_bb
, join_bb
));
3001 redirect_edge_and_branch_force (single_succ_edge (test_bb
), join_bb
);
3002 delete_basic_block (then_bb
);
3005 if (can_merge_blocks_p (test_bb
, join_bb
))
3007 merge_blocks (test_bb
, join_bb
);
3011 num_updated_if_blocks
++;
3016 pointer_map_destroy (then_vals
);
3017 pointer_map_destroy (else_vals
);
3018 then_regs
.release ();
3019 else_regs
.release ();
3024 /* Determine if a given basic block heads a simple IF-THEN-JOIN or an
3025 IF-THEN-ELSE-JOIN block.
3027 If so, we'll try to convert the insns to not require the branch,
3028 using only transformations that do not require conditional execution.
3030 Return TRUE if we were successful at converting the block. */
3033 noce_find_if_block (basic_block test_bb
, edge then_edge
, edge else_edge
,
3036 basic_block then_bb
, else_bb
, join_bb
;
3037 bool then_else_reversed
= false;
3040 struct noce_if_info if_info
;
3042 /* We only ever should get here before reload. */
3043 gcc_assert (!reload_completed
);
3045 /* Recognize an IF-THEN-ELSE-JOIN block. */
3046 if (single_pred_p (then_edge
->dest
)
3047 && single_succ_p (then_edge
->dest
)
3048 && single_pred_p (else_edge
->dest
)
3049 && single_succ_p (else_edge
->dest
)
3050 && single_succ (then_edge
->dest
) == single_succ (else_edge
->dest
))
3052 then_bb
= then_edge
->dest
;
3053 else_bb
= else_edge
->dest
;
3054 join_bb
= single_succ (then_bb
);
3056 /* Recognize an IF-THEN-JOIN block. */
3057 else if (single_pred_p (then_edge
->dest
)
3058 && single_succ_p (then_edge
->dest
)
3059 && single_succ (then_edge
->dest
) == else_edge
->dest
)
3061 then_bb
= then_edge
->dest
;
3062 else_bb
= NULL_BLOCK
;
3063 join_bb
= else_edge
->dest
;
3065 /* Recognize an IF-ELSE-JOIN block. We can have those because the order
3066 of basic blocks in cfglayout mode does not matter, so the fallthrough
3067 edge can go to any basic block (and not just to bb->next_bb, like in
3069 else if (single_pred_p (else_edge
->dest
)
3070 && single_succ_p (else_edge
->dest
)
3071 && single_succ (else_edge
->dest
) == then_edge
->dest
)
3073 /* The noce transformations do not apply to IF-ELSE-JOIN blocks.
3074 To make this work, we have to invert the THEN and ELSE blocks
3075 and reverse the jump condition. */
3076 then_bb
= else_edge
->dest
;
3077 else_bb
= NULL_BLOCK
;
3078 join_bb
= single_succ (then_bb
);
3079 then_else_reversed
= true;
3082 /* Not a form we can handle. */
3085 /* The edges of the THEN and ELSE blocks cannot have complex edges. */
3086 if (single_succ_edge (then_bb
)->flags
& EDGE_COMPLEX
)
3089 && single_succ_edge (else_bb
)->flags
& EDGE_COMPLEX
)
3092 num_possible_if_blocks
++;
3097 "\nIF-THEN%s-JOIN block found, pass %d, test %d, then %d",
3098 (else_bb
) ? "-ELSE" : "",
3099 pass
, test_bb
->index
, then_bb
->index
);
3102 fprintf (dump_file
, ", else %d", else_bb
->index
);
3104 fprintf (dump_file
, ", join %d\n", join_bb
->index
);
3107 /* If the conditional jump is more than just a conditional
3108 jump, then we can not do if-conversion on this block. */
3109 jump
= BB_END (test_bb
);
3110 if (! onlyjump_p (jump
))
3113 /* If this is not a standard conditional jump, we can't parse it. */
3114 cond
= noce_get_condition (jump
, &cond_earliest
, then_else_reversed
);
3118 /* We must be comparing objects whose modes imply the size. */
3119 if (GET_MODE (XEXP (cond
, 0)) == BLKmode
)
3122 /* Initialize an IF_INFO struct to pass around. */
3123 memset (&if_info
, 0, sizeof if_info
);
3124 if_info
.test_bb
= test_bb
;
3125 if_info
.then_bb
= then_bb
;
3126 if_info
.else_bb
= else_bb
;
3127 if_info
.join_bb
= join_bb
;
3128 if_info
.cond
= cond
;
3129 if_info
.cond_earliest
= cond_earliest
;
3130 if_info
.jump
= jump
;
3131 if_info
.then_else_reversed
= then_else_reversed
;
3132 if_info
.branch_cost
= BRANCH_COST (optimize_bb_for_speed_p (test_bb
),
3133 predictable_edge_p (then_edge
));
3135 /* Do the real work. */
3137 if (noce_process_if_block (&if_info
))
3140 if (HAVE_conditional_move
3141 && cond_move_process_if_block (&if_info
))
3148 /* Merge the blocks and mark for local life update. */
3151 merge_if_block (struct ce_if_block
* ce_info
)
3153 basic_block test_bb
= ce_info
->test_bb
; /* last test block */
3154 basic_block then_bb
= ce_info
->then_bb
; /* THEN */
3155 basic_block else_bb
= ce_info
->else_bb
; /* ELSE or NULL */
3156 basic_block join_bb
= ce_info
->join_bb
; /* join block */
3157 basic_block combo_bb
;
3159 /* All block merging is done into the lower block numbers. */
3162 df_set_bb_dirty (test_bb
);
3164 /* Merge any basic blocks to handle && and || subtests. Each of
3165 the blocks are on the fallthru path from the predecessor block. */
3166 if (ce_info
->num_multiple_test_blocks
> 0)
3168 basic_block bb
= test_bb
;
3169 basic_block last_test_bb
= ce_info
->last_test_bb
;
3170 basic_block fallthru
= block_fallthru (bb
);
3175 fallthru
= block_fallthru (bb
);
3176 merge_blocks (combo_bb
, bb
);
3179 while (bb
!= last_test_bb
);
3182 /* Merge TEST block into THEN block. Normally the THEN block won't have a
3183 label, but it might if there were || tests. That label's count should be
3184 zero, and it normally should be removed. */
3188 /* If THEN_BB has no successors, then there's a BARRIER after it.
3189 If COMBO_BB has more than one successor (THEN_BB), then that BARRIER
3190 is no longer needed, and in fact it is incorrect to leave it in
3192 if (EDGE_COUNT (then_bb
->succs
) == 0
3193 && EDGE_COUNT (combo_bb
->succs
) > 1)
3195 rtx end
= NEXT_INSN (BB_END (then_bb
));
3196 while (end
&& NOTE_P (end
) && !NOTE_INSN_BASIC_BLOCK_P (end
))
3197 end
= NEXT_INSN (end
);
3199 if (end
&& BARRIER_P (end
))
3202 merge_blocks (combo_bb
, then_bb
);
3206 /* The ELSE block, if it existed, had a label. That label count
3207 will almost always be zero, but odd things can happen when labels
3208 get their addresses taken. */
3211 /* If ELSE_BB has no successors, then there's a BARRIER after it.
3212 If COMBO_BB has more than one successor (ELSE_BB), then that BARRIER
3213 is no longer needed, and in fact it is incorrect to leave it in
3215 if (EDGE_COUNT (else_bb
->succs
) == 0
3216 && EDGE_COUNT (combo_bb
->succs
) > 1)
3218 rtx end
= NEXT_INSN (BB_END (else_bb
));
3219 while (end
&& NOTE_P (end
) && !NOTE_INSN_BASIC_BLOCK_P (end
))
3220 end
= NEXT_INSN (end
);
3222 if (end
&& BARRIER_P (end
))
3225 merge_blocks (combo_bb
, else_bb
);
3229 /* If there was no join block reported, that means it was not adjacent
3230 to the others, and so we cannot merge them. */
3234 rtx last
= BB_END (combo_bb
);
3236 /* The outgoing edge for the current COMBO block should already
3237 be correct. Verify this. */
3238 if (EDGE_COUNT (combo_bb
->succs
) == 0)
3239 gcc_assert (find_reg_note (last
, REG_NORETURN
, NULL
)
3240 || (NONJUMP_INSN_P (last
)
3241 && GET_CODE (PATTERN (last
)) == TRAP_IF
3242 && (TRAP_CONDITION (PATTERN (last
))
3243 == const_true_rtx
)));
3246 /* There should still be something at the end of the THEN or ELSE
3247 blocks taking us to our final destination. */
3248 gcc_assert (JUMP_P (last
)
3249 || (EDGE_SUCC (combo_bb
, 0)->dest
3250 == EXIT_BLOCK_PTR_FOR_FN (cfun
)
3252 && SIBLING_CALL_P (last
))
3253 || ((EDGE_SUCC (combo_bb
, 0)->flags
& EDGE_EH
)
3254 && can_throw_internal (last
)));
3257 /* The JOIN block may have had quite a number of other predecessors too.
3258 Since we've already merged the TEST, THEN and ELSE blocks, we should
3259 have only one remaining edge from our if-then-else diamond. If there
3260 is more than one remaining edge, it must come from elsewhere. There
3261 may be zero incoming edges if the THEN block didn't actually join
3262 back up (as with a call to a non-return function). */
3263 else if (EDGE_COUNT (join_bb
->preds
) < 2
3264 && join_bb
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
3266 /* We can merge the JOIN cleanly and update the dataflow try
3267 again on this pass.*/
3268 merge_blocks (combo_bb
, join_bb
);
3273 /* We cannot merge the JOIN. */
3275 /* The outgoing edge for the current COMBO block should already
3276 be correct. Verify this. */
3277 gcc_assert (single_succ_p (combo_bb
)
3278 && single_succ (combo_bb
) == join_bb
);
3280 /* Remove the jump and cruft from the end of the COMBO block. */
3281 if (join_bb
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
3282 tidy_fallthru_edge (single_succ_edge (combo_bb
));
3285 num_updated_if_blocks
++;
3288 /* Find a block ending in a simple IF condition and try to transform it
3289 in some way. When converting a multi-block condition, put the new code
3290 in the first such block and delete the rest. Return a pointer to this
3291 first block if some transformation was done. Return NULL otherwise. */
3294 find_if_header (basic_block test_bb
, int pass
)
3296 ce_if_block ce_info
;
3300 /* The kind of block we're looking for has exactly two successors. */
3301 if (EDGE_COUNT (test_bb
->succs
) != 2)
3304 then_edge
= EDGE_SUCC (test_bb
, 0);
3305 else_edge
= EDGE_SUCC (test_bb
, 1);
3307 if (df_get_bb_dirty (then_edge
->dest
))
3309 if (df_get_bb_dirty (else_edge
->dest
))
3312 /* Neither edge should be abnormal. */
3313 if ((then_edge
->flags
& EDGE_COMPLEX
)
3314 || (else_edge
->flags
& EDGE_COMPLEX
))
3317 /* Nor exit the loop. */
3318 if ((then_edge
->flags
& EDGE_LOOP_EXIT
)
3319 || (else_edge
->flags
& EDGE_LOOP_EXIT
))
3322 /* The THEN edge is canonically the one that falls through. */
3323 if (then_edge
->flags
& EDGE_FALLTHRU
)
3325 else if (else_edge
->flags
& EDGE_FALLTHRU
)
3328 else_edge
= then_edge
;
3332 /* Otherwise this must be a multiway branch of some sort. */
3335 memset (&ce_info
, 0, sizeof (ce_info
));
3336 ce_info
.test_bb
= test_bb
;
3337 ce_info
.then_bb
= then_edge
->dest
;
3338 ce_info
.else_bb
= else_edge
->dest
;
3339 ce_info
.pass
= pass
;
3341 #ifdef IFCVT_MACHDEP_INIT
3342 IFCVT_MACHDEP_INIT (&ce_info
);
3345 if (!reload_completed
3346 && noce_find_if_block (test_bb
, then_edge
, else_edge
, pass
))
3349 if (reload_completed
3350 && targetm
.have_conditional_execution ()
3351 && cond_exec_find_if_block (&ce_info
))
3355 && optab_handler (ctrap_optab
, word_mode
) != CODE_FOR_nothing
3356 && find_cond_trap (test_bb
, then_edge
, else_edge
))
3359 if (dom_info_state (CDI_POST_DOMINATORS
) >= DOM_NO_FAST_QUERY
3360 && (reload_completed
|| !targetm
.have_conditional_execution ()))
3362 if (find_if_case_1 (test_bb
, then_edge
, else_edge
))
3364 if (find_if_case_2 (test_bb
, then_edge
, else_edge
))
3372 fprintf (dump_file
, "Conversion succeeded on pass %d.\n", pass
);
3373 /* Set this so we continue looking. */
3374 cond_exec_changed_p
= TRUE
;
3375 return ce_info
.test_bb
;
3378 /* Return true if a block has two edges, one of which falls through to the next
3379 block, and the other jumps to a specific block, so that we can tell if the
3380 block is part of an && test or an || test. Returns either -1 or the number
3381 of non-note, non-jump, non-USE/CLOBBER insns in the block. */
3384 block_jumps_and_fallthru_p (basic_block cur_bb
, basic_block target_bb
)
3387 int fallthru_p
= FALSE
;
3394 if (!cur_bb
|| !target_bb
)
3397 /* If no edges, obviously it doesn't jump or fallthru. */
3398 if (EDGE_COUNT (cur_bb
->succs
) == 0)
3401 FOR_EACH_EDGE (cur_edge
, ei
, cur_bb
->succs
)
3403 if (cur_edge
->flags
& EDGE_COMPLEX
)
3404 /* Anything complex isn't what we want. */
3407 else if (cur_edge
->flags
& EDGE_FALLTHRU
)
3410 else if (cur_edge
->dest
== target_bb
)
3417 if ((jump_p
& fallthru_p
) == 0)
3420 /* Don't allow calls in the block, since this is used to group && and ||
3421 together for conditional execution support. ??? we should support
3422 conditional execution support across calls for IA-64 some day, but
3423 for now it makes the code simpler. */
3424 end
= BB_END (cur_bb
);
3425 insn
= BB_HEAD (cur_bb
);
3427 while (insn
!= NULL_RTX
)
3434 && !DEBUG_INSN_P (insn
)
3435 && GET_CODE (PATTERN (insn
)) != USE
3436 && GET_CODE (PATTERN (insn
)) != CLOBBER
)
3442 insn
= NEXT_INSN (insn
);
3448 /* Determine if a given basic block heads a simple IF-THEN or IF-THEN-ELSE
3449 block. If so, we'll try to convert the insns to not require the branch.
3450 Return TRUE if we were successful at converting the block. */
3453 cond_exec_find_if_block (struct ce_if_block
* ce_info
)
3455 basic_block test_bb
= ce_info
->test_bb
;
3456 basic_block then_bb
= ce_info
->then_bb
;
3457 basic_block else_bb
= ce_info
->else_bb
;
3458 basic_block join_bb
= NULL_BLOCK
;
3463 ce_info
->last_test_bb
= test_bb
;
3465 /* We only ever should get here after reload,
3466 and if we have conditional execution. */
3467 gcc_assert (reload_completed
&& targetm
.have_conditional_execution ());
3469 /* Discover if any fall through predecessors of the current test basic block
3470 were && tests (which jump to the else block) or || tests (which jump to
3472 if (single_pred_p (test_bb
)
3473 && single_pred_edge (test_bb
)->flags
== EDGE_FALLTHRU
)
3475 basic_block bb
= single_pred (test_bb
);
3476 basic_block target_bb
;
3477 int max_insns
= MAX_CONDITIONAL_EXECUTE
;
3480 /* Determine if the preceding block is an && or || block. */
3481 if ((n_insns
= block_jumps_and_fallthru_p (bb
, else_bb
)) >= 0)
3483 ce_info
->and_and_p
= TRUE
;
3484 target_bb
= else_bb
;
3486 else if ((n_insns
= block_jumps_and_fallthru_p (bb
, then_bb
)) >= 0)
3488 ce_info
->and_and_p
= FALSE
;
3489 target_bb
= then_bb
;
3492 target_bb
= NULL_BLOCK
;
3494 if (target_bb
&& n_insns
<= max_insns
)
3496 int total_insns
= 0;
3499 ce_info
->last_test_bb
= test_bb
;
3501 /* Found at least one && or || block, look for more. */
3504 ce_info
->test_bb
= test_bb
= bb
;
3505 total_insns
+= n_insns
;
3508 if (!single_pred_p (bb
))
3511 bb
= single_pred (bb
);
3512 n_insns
= block_jumps_and_fallthru_p (bb
, target_bb
);
3514 while (n_insns
>= 0 && (total_insns
+ n_insns
) <= max_insns
);
3516 ce_info
->num_multiple_test_blocks
= blocks
;
3517 ce_info
->num_multiple_test_insns
= total_insns
;
3519 if (ce_info
->and_and_p
)
3520 ce_info
->num_and_and_blocks
= blocks
;
3522 ce_info
->num_or_or_blocks
= blocks
;
3526 /* The THEN block of an IF-THEN combo must have exactly one predecessor,
3527 other than any || blocks which jump to the THEN block. */
3528 if ((EDGE_COUNT (then_bb
->preds
) - ce_info
->num_or_or_blocks
) != 1)
3531 /* The edges of the THEN and ELSE blocks cannot have complex edges. */
3532 FOR_EACH_EDGE (cur_edge
, ei
, then_bb
->preds
)
3534 if (cur_edge
->flags
& EDGE_COMPLEX
)
3538 FOR_EACH_EDGE (cur_edge
, ei
, else_bb
->preds
)
3540 if (cur_edge
->flags
& EDGE_COMPLEX
)
3544 /* The THEN block of an IF-THEN combo must have zero or one successors. */
3545 if (EDGE_COUNT (then_bb
->succs
) > 0
3546 && (!single_succ_p (then_bb
)
3547 || (single_succ_edge (then_bb
)->flags
& EDGE_COMPLEX
)
3548 || (epilogue_completed
3549 && tablejump_p (BB_END (then_bb
), NULL
, NULL
))))
3552 /* If the THEN block has no successors, conditional execution can still
3553 make a conditional call. Don't do this unless the ELSE block has
3554 only one incoming edge -- the CFG manipulation is too ugly otherwise.
3555 Check for the last insn of the THEN block being an indirect jump, which
3556 is listed as not having any successors, but confuses the rest of the CE
3557 code processing. ??? we should fix this in the future. */
3558 if (EDGE_COUNT (then_bb
->succs
) == 0)
3560 if (single_pred_p (else_bb
) && else_bb
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
3562 rtx last_insn
= BB_END (then_bb
);
3565 && NOTE_P (last_insn
)
3566 && last_insn
!= BB_HEAD (then_bb
))
3567 last_insn
= PREV_INSN (last_insn
);
3570 && JUMP_P (last_insn
)
3571 && ! simplejump_p (last_insn
))
3575 else_bb
= NULL_BLOCK
;
3581 /* If the THEN block's successor is the other edge out of the TEST block,
3582 then we have an IF-THEN combo without an ELSE. */
3583 else if (single_succ (then_bb
) == else_bb
)
3586 else_bb
= NULL_BLOCK
;
3589 /* If the THEN and ELSE block meet in a subsequent block, and the ELSE
3590 has exactly one predecessor and one successor, and the outgoing edge
3591 is not complex, then we have an IF-THEN-ELSE combo. */
3592 else if (single_succ_p (else_bb
)
3593 && single_succ (then_bb
) == single_succ (else_bb
)
3594 && single_pred_p (else_bb
)
3595 && !(single_succ_edge (else_bb
)->flags
& EDGE_COMPLEX
)
3596 && !(epilogue_completed
3597 && tablejump_p (BB_END (else_bb
), NULL
, NULL
)))
3598 join_bb
= single_succ (else_bb
);
3600 /* Otherwise it is not an IF-THEN or IF-THEN-ELSE combination. */
3604 num_possible_if_blocks
++;
3609 "\nIF-THEN%s block found, pass %d, start block %d "
3610 "[insn %d], then %d [%d]",
3611 (else_bb
) ? "-ELSE" : "",
3614 BB_HEAD (test_bb
) ? (int)INSN_UID (BB_HEAD (test_bb
)) : -1,
3616 BB_HEAD (then_bb
) ? (int)INSN_UID (BB_HEAD (then_bb
)) : -1);
3619 fprintf (dump_file
, ", else %d [%d]",
3621 BB_HEAD (else_bb
) ? (int)INSN_UID (BB_HEAD (else_bb
)) : -1);
3623 fprintf (dump_file
, ", join %d [%d]",
3625 BB_HEAD (join_bb
) ? (int)INSN_UID (BB_HEAD (join_bb
)) : -1);
3627 if (ce_info
->num_multiple_test_blocks
> 0)
3628 fprintf (dump_file
, ", %d %s block%s last test %d [%d]",
3629 ce_info
->num_multiple_test_blocks
,
3630 (ce_info
->and_and_p
) ? "&&" : "||",
3631 (ce_info
->num_multiple_test_blocks
== 1) ? "" : "s",
3632 ce_info
->last_test_bb
->index
,
3633 ((BB_HEAD (ce_info
->last_test_bb
))
3634 ? (int)INSN_UID (BB_HEAD (ce_info
->last_test_bb
))
3637 fputc ('\n', dump_file
);
3640 /* Make sure IF, THEN, and ELSE, blocks are adjacent. Actually, we get the
3641 first condition for free, since we've already asserted that there's a
3642 fallthru edge from IF to THEN. Likewise for the && and || blocks, since
3643 we checked the FALLTHRU flag, those are already adjacent to the last IF
3645 /* ??? As an enhancement, move the ELSE block. Have to deal with
3646 BLOCK notes, if by no other means than backing out the merge if they
3647 exist. Sticky enough I don't want to think about it now. */
3649 if (else_bb
&& (next
= next
->next_bb
) != else_bb
)
3651 if ((next
= next
->next_bb
) != join_bb
3652 && join_bb
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
3660 /* Do the real work. */
3662 ce_info
->else_bb
= else_bb
;
3663 ce_info
->join_bb
= join_bb
;
3665 /* If we have && and || tests, try to first handle combining the && and ||
3666 tests into the conditional code, and if that fails, go back and handle
3667 it without the && and ||, which at present handles the && case if there
3668 was no ELSE block. */
3669 if (cond_exec_process_if_block (ce_info
, TRUE
))
3672 if (ce_info
->num_multiple_test_blocks
)
3676 if (cond_exec_process_if_block (ce_info
, FALSE
))
3683 /* Convert a branch over a trap, or a branch
3684 to a trap, into a conditional trap. */
3687 find_cond_trap (basic_block test_bb
, edge then_edge
, edge else_edge
)
3689 basic_block then_bb
= then_edge
->dest
;
3690 basic_block else_bb
= else_edge
->dest
;
3691 basic_block other_bb
, trap_bb
;
3692 rtx trap
, jump
, cond
, cond_earliest
, seq
;
3695 /* Locate the block with the trap instruction. */
3696 /* ??? While we look for no successors, we really ought to allow
3697 EH successors. Need to fix merge_if_block for that to work. */
3698 if ((trap
= block_has_only_trap (then_bb
)) != NULL
)
3699 trap_bb
= then_bb
, other_bb
= else_bb
;
3700 else if ((trap
= block_has_only_trap (else_bb
)) != NULL
)
3701 trap_bb
= else_bb
, other_bb
= then_bb
;
3707 fprintf (dump_file
, "\nTRAP-IF block found, start %d, trap %d\n",
3708 test_bb
->index
, trap_bb
->index
);
3711 /* If this is not a standard conditional jump, we can't parse it. */
3712 jump
= BB_END (test_bb
);
3713 cond
= noce_get_condition (jump
, &cond_earliest
, false);
3717 /* If the conditional jump is more than just a conditional jump, then
3718 we can not do if-conversion on this block. */
3719 if (! onlyjump_p (jump
))
3722 /* We must be comparing objects whose modes imply the size. */
3723 if (GET_MODE (XEXP (cond
, 0)) == BLKmode
)
3726 /* Reverse the comparison code, if necessary. */
3727 code
= GET_CODE (cond
);
3728 if (then_bb
== trap_bb
)
3730 code
= reversed_comparison_code (cond
, jump
);
3731 if (code
== UNKNOWN
)
3735 /* Attempt to generate the conditional trap. */
3736 seq
= gen_cond_trap (code
, copy_rtx (XEXP (cond
, 0)),
3737 copy_rtx (XEXP (cond
, 1)),
3738 TRAP_CODE (PATTERN (trap
)));
3742 /* Emit the new insns before cond_earliest. */
3743 emit_insn_before_setloc (seq
, cond_earliest
, INSN_LOCATION (trap
));
3745 /* Delete the trap block if possible. */
3746 remove_edge (trap_bb
== then_bb
? then_edge
: else_edge
);
3747 df_set_bb_dirty (test_bb
);
3748 df_set_bb_dirty (then_bb
);
3749 df_set_bb_dirty (else_bb
);
3751 if (EDGE_COUNT (trap_bb
->preds
) == 0)
3753 delete_basic_block (trap_bb
);
3757 /* Wire together the blocks again. */
3758 if (current_ir_type () == IR_RTL_CFGLAYOUT
)
3759 single_succ_edge (test_bb
)->flags
|= EDGE_FALLTHRU
;
3760 else if (trap_bb
== then_bb
)
3764 lab
= JUMP_LABEL (jump
);
3765 newjump
= emit_jump_insn_after (gen_jump (lab
), jump
);
3766 LABEL_NUSES (lab
) += 1;
3767 JUMP_LABEL (newjump
) = lab
;
3768 emit_barrier_after (newjump
);
3772 if (can_merge_blocks_p (test_bb
, other_bb
))
3774 merge_blocks (test_bb
, other_bb
);
3778 num_updated_if_blocks
++;
3782 /* Subroutine of find_cond_trap: if BB contains only a trap insn,
3786 block_has_only_trap (basic_block bb
)
3790 /* We're not the exit block. */
3791 if (bb
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
3794 /* The block must have no successors. */
3795 if (EDGE_COUNT (bb
->succs
) > 0)
3798 /* The only instruction in the THEN block must be the trap. */
3799 trap
= first_active_insn (bb
);
3800 if (! (trap
== BB_END (bb
)
3801 && GET_CODE (PATTERN (trap
)) == TRAP_IF
3802 && TRAP_CONDITION (PATTERN (trap
)) == const_true_rtx
))
3808 /* Look for IF-THEN-ELSE cases in which one of THEN or ELSE is
3809 transformable, but not necessarily the other. There need be no
3812 Return TRUE if we were successful at converting the block.
3814 Cases we'd like to look at:
3817 if (test) goto over; // x not live
3825 if (! test) goto label;
3828 if (test) goto E; // x not live
3842 (3) // This one's really only interesting for targets that can do
3843 // multiway branching, e.g. IA-64 BBB bundles. For other targets
3844 // it results in multiple branches on a cache line, which often
3845 // does not sit well with predictors.
3847 if (test1) goto E; // predicted not taken
3863 (A) Don't do (2) if the branch is predicted against the block we're
3864 eliminating. Do it anyway if we can eliminate a branch; this requires
3865 that the sole successor of the eliminated block postdominate the other
3868 (B) With CE, on (3) we can steal from both sides of the if, creating
3877 Again, this is most useful if J postdominates.
3879 (C) CE substitutes for helpful life information.
3881 (D) These heuristics need a lot of work. */
3883 /* Tests for case 1 above. */
3886 find_if_case_1 (basic_block test_bb
, edge then_edge
, edge else_edge
)
3888 basic_block then_bb
= then_edge
->dest
;
3889 basic_block else_bb
= else_edge
->dest
;
3891 int then_bb_index
, then_prob
;
3892 rtx else_target
= NULL_RTX
;
3894 /* If we are partitioning hot/cold basic blocks, we don't want to
3895 mess up unconditional or indirect jumps that cross between hot
3898 Basic block partitioning may result in some jumps that appear to
3899 be optimizable (or blocks that appear to be mergeable), but which really
3900 must be left untouched (they are required to make it safely across
3901 partition boundaries). See the comments at the top of
3902 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
3904 if ((BB_END (then_bb
)
3905 && find_reg_note (BB_END (then_bb
), REG_CROSSING_JUMP
, NULL_RTX
))
3906 || (BB_END (test_bb
)
3907 && find_reg_note (BB_END (test_bb
), REG_CROSSING_JUMP
, NULL_RTX
))
3908 || (BB_END (else_bb
)
3909 && find_reg_note (BB_END (else_bb
), REG_CROSSING_JUMP
,
3913 /* THEN has one successor. */
3914 if (!single_succ_p (then_bb
))
3917 /* THEN does not fall through, but is not strange either. */
3918 if (single_succ_edge (then_bb
)->flags
& (EDGE_COMPLEX
| EDGE_FALLTHRU
))
3921 /* THEN has one predecessor. */
3922 if (!single_pred_p (then_bb
))
3925 /* THEN must do something. */
3926 if (forwarder_block_p (then_bb
))
3929 num_possible_if_blocks
++;
3932 "\nIF-CASE-1 found, start %d, then %d\n",
3933 test_bb
->index
, then_bb
->index
);
3935 if (then_edge
->probability
)
3936 then_prob
= REG_BR_PROB_BASE
- then_edge
->probability
;
3938 then_prob
= REG_BR_PROB_BASE
/ 2;
3940 /* We're speculating from the THEN path, we want to make sure the cost
3941 of speculation is within reason. */
3942 if (! cheap_bb_rtx_cost_p (then_bb
, then_prob
,
3943 COSTS_N_INSNS (BRANCH_COST (optimize_bb_for_speed_p (then_edge
->src
),
3944 predictable_edge_p (then_edge
)))))
3947 if (else_bb
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
3949 rtx jump
= BB_END (else_edge
->src
);
3950 gcc_assert (JUMP_P (jump
));
3951 else_target
= JUMP_LABEL (jump
);
3954 /* Registers set are dead, or are predicable. */
3955 if (! dead_or_predicable (test_bb
, then_bb
, else_bb
,
3956 single_succ_edge (then_bb
), 1))
3959 /* Conversion went ok, including moving the insns and fixing up the
3960 jump. Adjust the CFG to match. */
3962 /* We can avoid creating a new basic block if then_bb is immediately
3963 followed by else_bb, i.e. deleting then_bb allows test_bb to fall
3964 through to else_bb. */
3966 if (then_bb
->next_bb
== else_bb
3967 && then_bb
->prev_bb
== test_bb
3968 && else_bb
!= EXIT_BLOCK_PTR_FOR_FN (cfun
))
3970 redirect_edge_succ (FALLTHRU_EDGE (test_bb
), else_bb
);
3973 else if (else_bb
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
3974 new_bb
= force_nonfallthru_and_redirect (FALLTHRU_EDGE (test_bb
),
3975 else_bb
, else_target
);
3977 new_bb
= redirect_edge_and_branch_force (FALLTHRU_EDGE (test_bb
),
3980 df_set_bb_dirty (test_bb
);
3981 df_set_bb_dirty (else_bb
);
3983 then_bb_index
= then_bb
->index
;
3984 delete_basic_block (then_bb
);
3986 /* Make rest of code believe that the newly created block is the THEN_BB
3987 block we removed. */
3990 df_bb_replace (then_bb_index
, new_bb
);
3991 /* This should have been done above via force_nonfallthru_and_redirect
3992 (possibly called from redirect_edge_and_branch_force). */
3993 gcc_checking_assert (BB_PARTITION (new_bb
) == BB_PARTITION (test_bb
));
3997 num_updated_if_blocks
++;
4002 /* Test for case 2 above. */
4005 find_if_case_2 (basic_block test_bb
, edge then_edge
, edge else_edge
)
4007 basic_block then_bb
= then_edge
->dest
;
4008 basic_block else_bb
= else_edge
->dest
;
4010 int then_prob
, else_prob
;
4012 /* We do not want to speculate (empty) loop latches. */
4014 && else_bb
->loop_father
->latch
== else_bb
)
4017 /* If we are partitioning hot/cold basic blocks, we don't want to
4018 mess up unconditional or indirect jumps that cross between hot
4021 Basic block partitioning may result in some jumps that appear to
4022 be optimizable (or blocks that appear to be mergeable), but which really
4023 must be left untouched (they are required to make it safely across
4024 partition boundaries). See the comments at the top of
4025 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
4027 if ((BB_END (then_bb
)
4028 && find_reg_note (BB_END (then_bb
), REG_CROSSING_JUMP
, NULL_RTX
))
4029 || (BB_END (test_bb
)
4030 && find_reg_note (BB_END (test_bb
), REG_CROSSING_JUMP
, NULL_RTX
))
4031 || (BB_END (else_bb
)
4032 && find_reg_note (BB_END (else_bb
), REG_CROSSING_JUMP
,
4036 /* ELSE has one successor. */
4037 if (!single_succ_p (else_bb
))
4040 else_succ
= single_succ_edge (else_bb
);
4042 /* ELSE outgoing edge is not complex. */
4043 if (else_succ
->flags
& EDGE_COMPLEX
)
4046 /* ELSE has one predecessor. */
4047 if (!single_pred_p (else_bb
))
4050 /* THEN is not EXIT. */
4051 if (then_bb
->index
< NUM_FIXED_BLOCKS
)
4054 if (else_edge
->probability
)
4056 else_prob
= else_edge
->probability
;
4057 then_prob
= REG_BR_PROB_BASE
- else_prob
;
4061 else_prob
= REG_BR_PROB_BASE
/ 2;
4062 then_prob
= REG_BR_PROB_BASE
/ 2;
4065 /* ELSE is predicted or SUCC(ELSE) postdominates THEN. */
4066 if (else_prob
> then_prob
)
4068 else if (else_succ
->dest
->index
< NUM_FIXED_BLOCKS
4069 || dominated_by_p (CDI_POST_DOMINATORS
, then_bb
,
4075 num_possible_if_blocks
++;
4078 "\nIF-CASE-2 found, start %d, else %d\n",
4079 test_bb
->index
, else_bb
->index
);
4081 /* We're speculating from the ELSE path, we want to make sure the cost
4082 of speculation is within reason. */
4083 if (! cheap_bb_rtx_cost_p (else_bb
, else_prob
,
4084 COSTS_N_INSNS (BRANCH_COST (optimize_bb_for_speed_p (else_edge
->src
),
4085 predictable_edge_p (else_edge
)))))
4088 /* Registers set are dead, or are predicable. */
4089 if (! dead_or_predicable (test_bb
, else_bb
, then_bb
, else_succ
, 0))
4092 /* Conversion went ok, including moving the insns and fixing up the
4093 jump. Adjust the CFG to match. */
4095 df_set_bb_dirty (test_bb
);
4096 df_set_bb_dirty (then_bb
);
4097 delete_basic_block (else_bb
);
4100 num_updated_if_blocks
++;
4102 /* ??? We may now fallthru from one of THEN's successors into a join
4103 block. Rerun cleanup_cfg? Examine things manually? Wait? */
4108 /* Used by the code above to perform the actual rtl transformations.
4109 Return TRUE if successful.
4111 TEST_BB is the block containing the conditional branch. MERGE_BB
4112 is the block containing the code to manipulate. DEST_EDGE is an
4113 edge representing a jump to the join block; after the conversion,
4114 TEST_BB should be branching to its destination.
4115 REVERSEP is true if the sense of the branch should be reversed. */
4118 dead_or_predicable (basic_block test_bb
, basic_block merge_bb
,
4119 basic_block other_bb
, edge dest_edge
, int reversep
)
4121 basic_block new_dest
= dest_edge
->dest
;
4122 rtx head
, end
, jump
, earliest
= NULL_RTX
, old_dest
;
4123 bitmap merge_set
= NULL
;
4124 /* Number of pending changes. */
4125 int n_validated_changes
= 0;
4126 rtx new_dest_label
= NULL_RTX
;
4128 jump
= BB_END (test_bb
);
4130 /* Find the extent of the real code in the merge block. */
4131 head
= BB_HEAD (merge_bb
);
4132 end
= BB_END (merge_bb
);
4134 while (DEBUG_INSN_P (end
) && end
!= head
)
4135 end
= PREV_INSN (end
);
4137 /* If merge_bb ends with a tablejump, predicating/moving insn's
4138 into test_bb and then deleting merge_bb will result in the jumptable
4139 that follows merge_bb being removed along with merge_bb and then we
4140 get an unresolved reference to the jumptable. */
4141 if (tablejump_p (end
, NULL
, NULL
))
4145 head
= NEXT_INSN (head
);
4146 while (DEBUG_INSN_P (head
) && head
!= end
)
4147 head
= NEXT_INSN (head
);
4152 head
= end
= NULL_RTX
;
4155 head
= NEXT_INSN (head
);
4156 while (DEBUG_INSN_P (head
) && head
!= end
)
4157 head
= NEXT_INSN (head
);
4164 head
= end
= NULL_RTX
;
4167 end
= PREV_INSN (end
);
4168 while (DEBUG_INSN_P (end
) && end
!= head
)
4169 end
= PREV_INSN (end
);
4172 /* Don't move frame-related insn across the conditional branch. This
4173 can lead to one of the paths of the branch having wrong unwind info. */
4174 if (epilogue_completed
)
4179 if (INSN_P (insn
) && RTX_FRAME_RELATED_P (insn
))
4183 insn
= NEXT_INSN (insn
);
4187 /* Disable handling dead code by conditional execution if the machine needs
4188 to do anything funny with the tests, etc. */
4189 #ifndef IFCVT_MODIFY_TESTS
4190 if (targetm
.have_conditional_execution ())
4192 /* In the conditional execution case, we have things easy. We know
4193 the condition is reversible. We don't have to check life info
4194 because we're going to conditionally execute the code anyway.
4195 All that's left is making sure the insns involved can actually
4200 cond
= cond_exec_get_condition (jump
);
4204 rtx note
= find_reg_note (jump
, REG_BR_PROB
, NULL_RTX
);
4205 int prob_val
= (note
? XINT (note
, 0) : -1);
4209 enum rtx_code rev
= reversed_comparison_code (cond
, jump
);
4212 cond
= gen_rtx_fmt_ee (rev
, GET_MODE (cond
), XEXP (cond
, 0),
4215 prob_val
= REG_BR_PROB_BASE
- prob_val
;
4218 if (cond_exec_process_insns (NULL
, head
, end
, cond
, prob_val
, 0)
4219 && verify_changes (0))
4220 n_validated_changes
= num_validated_changes ();
4228 /* If we allocated new pseudos (e.g. in the conditional move
4229 expander called from noce_emit_cmove), we must resize the
4231 if (max_regno
< max_reg_num ())
4232 max_regno
= max_reg_num ();
4234 /* Try the NCE path if the CE path did not result in any changes. */
4235 if (n_validated_changes
== 0)
4241 /* In the non-conditional execution case, we have to verify that there
4242 are no trapping operations, no calls, no references to memory, and
4243 that any registers modified are dead at the branch site. */
4245 if (!any_condjump_p (jump
))
4248 /* Find the extent of the conditional. */
4249 cond
= noce_get_condition (jump
, &earliest
, false);
4253 live
= BITMAP_ALLOC (®_obstack
);
4254 simulate_backwards_to_point (merge_bb
, live
, end
);
4255 success
= can_move_insns_across (head
, end
, earliest
, jump
,
4257 df_get_live_in (other_bb
), NULL
);
4262 /* Collect the set of registers set in MERGE_BB. */
4263 merge_set
= BITMAP_ALLOC (®_obstack
);
4265 FOR_BB_INSNS (merge_bb
, insn
)
4266 if (NONDEBUG_INSN_P (insn
))
4267 df_simulate_find_defs (insn
, merge_set
);
4269 #ifdef HAVE_simple_return
4270 /* If shrink-wrapping, disable this optimization when test_bb is
4271 the first basic block and merge_bb exits. The idea is to not
4272 move code setting up a return register as that may clobber a
4273 register used to pass function parameters, which then must be
4274 saved in caller-saved regs. A caller-saved reg requires the
4275 prologue, killing a shrink-wrap opportunity. */
4276 if ((flag_shrink_wrap
&& HAVE_simple_return
&& !epilogue_completed
)
4277 && ENTRY_BLOCK_PTR_FOR_FN (cfun
)->next_bb
== test_bb
4278 && single_succ_p (new_dest
)
4279 && single_succ (new_dest
) == EXIT_BLOCK_PTR_FOR_FN (cfun
)
4280 && bitmap_intersect_p (df_get_live_in (new_dest
), merge_set
))
4285 return_regs
= BITMAP_ALLOC (®_obstack
);
4287 /* Start off with the intersection of regs used to pass
4288 params and regs used to return values. */
4289 for (i
= 0; i
< FIRST_PSEUDO_REGISTER
; i
++)
4290 if (FUNCTION_ARG_REGNO_P (i
)
4291 && targetm
.calls
.function_value_regno_p (i
))
4292 bitmap_set_bit (return_regs
, INCOMING_REGNO (i
));
4294 bitmap_and_into (return_regs
,
4295 df_get_live_out (ENTRY_BLOCK_PTR_FOR_FN (cfun
)));
4296 bitmap_and_into (return_regs
,
4297 df_get_live_in (EXIT_BLOCK_PTR_FOR_FN (cfun
)));
4298 if (!bitmap_empty_p (return_regs
))
4300 FOR_BB_INSNS_REVERSE (new_dest
, insn
)
4301 if (NONDEBUG_INSN_P (insn
))
4304 unsigned int uid
= INSN_UID (insn
);
4306 /* If this insn sets any reg in return_regs.. */
4307 for (def_rec
= DF_INSN_UID_DEFS (uid
); *def_rec
; def_rec
++)
4309 df_ref def
= *def_rec
;
4310 unsigned r
= DF_REF_REGNO (def
);
4312 if (bitmap_bit_p (return_regs
, r
))
4315 /* ..then add all reg uses to the set of regs
4316 we're interested in. */
4318 df_simulate_uses (insn
, return_regs
);
4320 if (bitmap_intersect_p (merge_set
, return_regs
))
4322 BITMAP_FREE (return_regs
);
4323 BITMAP_FREE (merge_set
);
4327 BITMAP_FREE (return_regs
);
4333 /* We don't want to use normal invert_jump or redirect_jump because
4334 we don't want to delete_insn called. Also, we want to do our own
4335 change group management. */
4337 old_dest
= JUMP_LABEL (jump
);
4338 if (other_bb
!= new_dest
)
4340 if (!any_condjump_p (jump
))
4343 if (JUMP_P (BB_END (dest_edge
->src
)))
4344 new_dest_label
= JUMP_LABEL (BB_END (dest_edge
->src
));
4345 else if (new_dest
== EXIT_BLOCK_PTR_FOR_FN (cfun
))
4346 new_dest_label
= ret_rtx
;
4348 new_dest_label
= block_label (new_dest
);
4351 ? ! invert_jump_1 (jump
, new_dest_label
)
4352 : ! redirect_jump_1 (jump
, new_dest_label
))
4356 if (verify_changes (n_validated_changes
))
4357 confirm_change_group ();
4361 if (other_bb
!= new_dest
)
4363 redirect_jump_2 (jump
, old_dest
, new_dest_label
, 0, reversep
);
4365 redirect_edge_succ (BRANCH_EDGE (test_bb
), new_dest
);
4368 gcov_type count
, probability
;
4369 count
= BRANCH_EDGE (test_bb
)->count
;
4370 BRANCH_EDGE (test_bb
)->count
= FALLTHRU_EDGE (test_bb
)->count
;
4371 FALLTHRU_EDGE (test_bb
)->count
= count
;
4372 probability
= BRANCH_EDGE (test_bb
)->probability
;
4373 BRANCH_EDGE (test_bb
)->probability
4374 = FALLTHRU_EDGE (test_bb
)->probability
;
4375 FALLTHRU_EDGE (test_bb
)->probability
= probability
;
4376 update_br_prob_note (test_bb
);
4380 /* Move the insns out of MERGE_BB to before the branch. */
4385 if (end
== BB_END (merge_bb
))
4386 BB_END (merge_bb
) = PREV_INSN (head
);
4388 /* PR 21767: when moving insns above a conditional branch, the REG_EQUAL
4389 notes being moved might become invalid. */
4395 if (! INSN_P (insn
))
4397 note
= find_reg_note (insn
, REG_EQUAL
, NULL_RTX
);
4400 remove_note (insn
, note
);
4401 } while (insn
!= end
&& (insn
= NEXT_INSN (insn
)));
4403 /* PR46315: when moving insns above a conditional branch, the REG_EQUAL
4404 notes referring to the registers being set might become invalid. */
4410 EXECUTE_IF_SET_IN_BITMAP (merge_set
, 0, i
, bi
)
4411 remove_reg_equal_equiv_notes_for_regno (i
);
4413 BITMAP_FREE (merge_set
);
4416 reorder_insns (head
, end
, PREV_INSN (earliest
));
4419 /* Remove the jump and edge if we can. */
4420 if (other_bb
== new_dest
)
4423 remove_edge (BRANCH_EDGE (test_bb
));
4424 /* ??? Can't merge blocks here, as then_bb is still in use.
4425 At minimum, the merge will get done just before bb-reorder. */
4434 BITMAP_FREE (merge_set
);
4439 /* Main entry point for all if-conversion. AFTER_COMBINE is true if
4440 we are after combine pass. */
4443 if_convert (bool after_combine
)
4450 df_live_add_problem ();
4451 df_live_set_all_dirty ();
4454 /* Record whether we are after combine pass. */
4455 ifcvt_after_combine
= after_combine
;
4456 num_possible_if_blocks
= 0;
4457 num_updated_if_blocks
= 0;
4458 num_true_changes
= 0;
4460 loop_optimizer_init (AVOID_CFG_MODIFICATIONS
);
4461 mark_loop_exit_edges ();
4462 loop_optimizer_finalize ();
4463 free_dominance_info (CDI_DOMINATORS
);
4465 /* Compute postdominators. */
4466 calculate_dominance_info (CDI_POST_DOMINATORS
);
4468 df_set_flags (DF_LR_RUN_DCE
);
4470 /* Go through each of the basic blocks looking for things to convert. If we
4471 have conditional execution, we make multiple passes to allow us to handle
4472 IF-THEN{-ELSE} blocks within other IF-THEN{-ELSE} blocks. */
4477 /* Only need to do dce on the first pass. */
4478 df_clear_flags (DF_LR_RUN_DCE
);
4479 cond_exec_changed_p
= FALSE
;
4482 #ifdef IFCVT_MULTIPLE_DUMPS
4483 if (dump_file
&& pass
> 1)
4484 fprintf (dump_file
, "\n\n========== Pass %d ==========\n", pass
);
4487 FOR_EACH_BB_FN (bb
, cfun
)
4490 while (!df_get_bb_dirty (bb
)
4491 && (new_bb
= find_if_header (bb
, pass
)) != NULL
)
4495 #ifdef IFCVT_MULTIPLE_DUMPS
4496 if (dump_file
&& cond_exec_changed_p
)
4497 print_rtl_with_bb (dump_file
, get_insns (), dump_flags
);
4500 while (cond_exec_changed_p
);
4502 #ifdef IFCVT_MULTIPLE_DUMPS
4504 fprintf (dump_file
, "\n\n========== no more changes\n");
4507 free_dominance_info (CDI_POST_DOMINATORS
);
4512 clear_aux_for_blocks ();
4514 /* If we allocated new pseudos, we must resize the array for sched1. */
4515 if (max_regno
< max_reg_num ())
4516 max_regno
= max_reg_num ();
4518 /* Write the final stats. */
4519 if (dump_file
&& num_possible_if_blocks
> 0)
4522 "\n%d possible IF blocks searched.\n",
4523 num_possible_if_blocks
);
4525 "%d IF blocks converted.\n",
4526 num_updated_if_blocks
);
4528 "%d true changes made.\n\n\n",
4533 df_remove_problem (df_live
);
4535 #ifdef ENABLE_CHECKING
4536 verify_flow_info ();
4541 gate_handle_if_conversion (void)
4543 return (optimize
> 0)
4544 && dbg_cnt (if_conversion
);
4547 /* If-conversion and CFG cleanup. */
4549 rest_of_handle_if_conversion (void)
4551 if (flag_if_conversion
)
4555 dump_reg_info (dump_file
);
4556 dump_flow_info (dump_file
, dump_flags
);
4558 cleanup_cfg (CLEANUP_EXPENSIVE
);
4568 const pass_data pass_data_rtl_ifcvt
=
4570 RTL_PASS
, /* type */
4572 OPTGROUP_NONE
, /* optinfo_flags */
4573 true, /* has_gate */
4574 true, /* has_execute */
4575 TV_IFCVT
, /* tv_id */
4576 0, /* properties_required */
4577 0, /* properties_provided */
4578 0, /* properties_destroyed */
4579 0, /* todo_flags_start */
4580 ( TODO_df_finish
| TODO_verify_rtl_sharing
| 0 ), /* todo_flags_finish */
4583 class pass_rtl_ifcvt
: public rtl_opt_pass
4586 pass_rtl_ifcvt (gcc::context
*ctxt
)
4587 : rtl_opt_pass (pass_data_rtl_ifcvt
, ctxt
)
4590 /* opt_pass methods: */
4591 bool gate () { return gate_handle_if_conversion (); }
4592 unsigned int execute () { return rest_of_handle_if_conversion (); }
4594 }; // class pass_rtl_ifcvt
4599 make_pass_rtl_ifcvt (gcc::context
*ctxt
)
4601 return new pass_rtl_ifcvt (ctxt
);
4605 gate_handle_if_after_combine (void)
4607 return optimize
> 0 && flag_if_conversion
4608 && dbg_cnt (if_after_combine
);
4612 /* Rerun if-conversion, as combine may have simplified things enough
4613 to now meet sequence length restrictions. */
4615 rest_of_handle_if_after_combine (void)
4623 const pass_data pass_data_if_after_combine
=
4625 RTL_PASS
, /* type */
4627 OPTGROUP_NONE
, /* optinfo_flags */
4628 true, /* has_gate */
4629 true, /* has_execute */
4630 TV_IFCVT
, /* tv_id */
4631 0, /* properties_required */
4632 0, /* properties_provided */
4633 0, /* properties_destroyed */
4634 0, /* todo_flags_start */
4635 ( TODO_df_finish
| TODO_verify_rtl_sharing
), /* todo_flags_finish */
4638 class pass_if_after_combine
: public rtl_opt_pass
4641 pass_if_after_combine (gcc::context
*ctxt
)
4642 : rtl_opt_pass (pass_data_if_after_combine
, ctxt
)
4645 /* opt_pass methods: */
4646 bool gate () { return gate_handle_if_after_combine (); }
4647 unsigned int execute () { return rest_of_handle_if_after_combine (); }
4649 }; // class pass_if_after_combine
4654 make_pass_if_after_combine (gcc::context
*ctxt
)
4656 return new pass_if_after_combine (ctxt
);
4661 gate_handle_if_after_reload (void)
4663 return optimize
> 0 && flag_if_conversion2
4664 && dbg_cnt (if_after_reload
);
4668 rest_of_handle_if_after_reload (void)
4677 const pass_data pass_data_if_after_reload
=
4679 RTL_PASS
, /* type */
4681 OPTGROUP_NONE
, /* optinfo_flags */
4682 true, /* has_gate */
4683 true, /* has_execute */
4684 TV_IFCVT2
, /* tv_id */
4685 0, /* properties_required */
4686 0, /* properties_provided */
4687 0, /* properties_destroyed */
4688 0, /* todo_flags_start */
4689 ( TODO_df_finish
| TODO_verify_rtl_sharing
), /* todo_flags_finish */
4692 class pass_if_after_reload
: public rtl_opt_pass
4695 pass_if_after_reload (gcc::context
*ctxt
)
4696 : rtl_opt_pass (pass_data_if_after_reload
, ctxt
)
4699 /* opt_pass methods: */
4700 bool gate () { return gate_handle_if_after_reload (); }
4701 unsigned int execute () { return rest_of_handle_if_after_reload (); }
4703 }; // class pass_if_after_reload
4708 make_pass_if_after_reload (gcc::context
*ctxt
)
4710 return new pass_if_after_reload (ctxt
);