1 /* If-conversion support.
2 Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2010
3 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it
8 under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3, or (at your option)
12 GCC is distributed in the hope that it will be useful, but WITHOUT
13 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
14 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
15 License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
23 #include "coretypes.h"
30 #include "insn-config.h"
33 #include "hard-reg-set.h"
34 #include "basic-block.h"
38 #include "diagnostic-core.h"
44 #include "tree-pass.h"
50 #ifndef HAVE_conditional_move
51 #define HAVE_conditional_move 0
63 #ifndef MAX_CONDITIONAL_EXECUTE
64 #define MAX_CONDITIONAL_EXECUTE \
65 (BRANCH_COST (optimize_function_for_speed_p (cfun), false) \
69 #define IFCVT_MULTIPLE_DUMPS 1
71 #define NULL_BLOCK ((basic_block) NULL)
73 /* # of IF-THEN or IF-THEN-ELSE blocks we looked at */
74 static int num_possible_if_blocks
;
76 /* # of IF-THEN or IF-THEN-ELSE blocks were converted to conditional
78 static int num_updated_if_blocks
;
80 /* # of changes made. */
81 static int num_true_changes
;
83 /* Whether conditional execution changes were made. */
84 static int cond_exec_changed_p
;
86 /* Forward references. */
87 static int count_bb_insns (const_basic_block
);
88 static bool cheap_bb_rtx_cost_p (const_basic_block
, int);
89 static rtx
first_active_insn (basic_block
);
90 static rtx
last_active_insn (basic_block
, int);
91 static rtx
find_active_insn_before (basic_block
, rtx
);
92 static rtx
find_active_insn_after (basic_block
, rtx
);
93 static basic_block
block_fallthru (basic_block
);
94 static int cond_exec_process_insns (ce_if_block_t
*, rtx
, rtx
, rtx
, rtx
, int);
95 static rtx
cond_exec_get_condition (rtx
);
96 static rtx
noce_get_condition (rtx
, rtx
*, bool);
97 static int noce_operand_ok (const_rtx
);
98 static void merge_if_block (ce_if_block_t
*);
99 static int find_cond_trap (basic_block
, edge
, edge
);
100 static basic_block
find_if_header (basic_block
, int);
101 static int block_jumps_and_fallthru_p (basic_block
, basic_block
);
102 static int noce_find_if_block (basic_block
, edge
, edge
, int);
103 static int cond_exec_find_if_block (ce_if_block_t
*);
104 static int find_if_case_1 (basic_block
, edge
, edge
);
105 static int find_if_case_2 (basic_block
, edge
, edge
);
106 static int dead_or_predicable (basic_block
, basic_block
, basic_block
,
108 static void noce_emit_move_insn (rtx
, rtx
);
109 static rtx
block_has_only_trap (basic_block
);
111 /* Count the number of non-jump active insns in BB. */
114 count_bb_insns (const_basic_block bb
)
117 rtx insn
= BB_HEAD (bb
);
121 if (CALL_P (insn
) || NONJUMP_INSN_P (insn
))
124 if (insn
== BB_END (bb
))
126 insn
= NEXT_INSN (insn
);
132 /* Determine whether the total insn_rtx_cost on non-jump insns in
133 basic block BB is less than MAX_COST. This function returns
134 false if the cost of any instruction could not be estimated. */
137 cheap_bb_rtx_cost_p (const_basic_block bb
, int max_cost
)
140 rtx insn
= BB_HEAD (bb
);
141 bool speed
= optimize_bb_for_speed_p (bb
);
145 if (NONJUMP_INSN_P (insn
))
147 int cost
= insn_rtx_cost (PATTERN (insn
), speed
);
151 /* If this instruction is the load or set of a "stack" register,
152 such as a floating point register on x87, then the cost of
153 speculatively executing this insn may need to include
154 the additional cost of popping its result off of the
155 register stack. Unfortunately, correctly recognizing and
156 accounting for this additional overhead is tricky, so for
157 now we simply prohibit such speculative execution. */
160 rtx set
= single_set (insn
);
161 if (set
&& STACK_REG_P (SET_DEST (set
)))
167 if (count
>= max_cost
)
170 else if (CALL_P (insn
))
173 if (insn
== BB_END (bb
))
175 insn
= NEXT_INSN (insn
);
181 /* Return the first non-jump active insn in the basic block. */
184 first_active_insn (basic_block bb
)
186 rtx insn
= BB_HEAD (bb
);
190 if (insn
== BB_END (bb
))
192 insn
= NEXT_INSN (insn
);
195 while (NOTE_P (insn
) || DEBUG_INSN_P (insn
))
197 if (insn
== BB_END (bb
))
199 insn
= NEXT_INSN (insn
);
208 /* Return the last non-jump active (non-jump) insn in the basic block. */
211 last_active_insn (basic_block bb
, int skip_use_p
)
213 rtx insn
= BB_END (bb
);
214 rtx head
= BB_HEAD (bb
);
218 || DEBUG_INSN_P (insn
)
220 && NONJUMP_INSN_P (insn
)
221 && GET_CODE (PATTERN (insn
)) == USE
))
225 insn
= PREV_INSN (insn
);
234 /* Return the active insn before INSN inside basic block CURR_BB. */
237 find_active_insn_before (basic_block curr_bb
, rtx insn
)
239 if (!insn
|| insn
== BB_HEAD (curr_bb
))
242 while ((insn
= PREV_INSN (insn
)) != NULL_RTX
)
244 if (NONJUMP_INSN_P (insn
) || JUMP_P (insn
) || CALL_P (insn
))
247 /* No other active insn all the way to the start of the basic block. */
248 if (insn
== BB_HEAD (curr_bb
))
255 /* Return the active insn after INSN inside basic block CURR_BB. */
258 find_active_insn_after (basic_block curr_bb
, rtx insn
)
260 if (!insn
|| insn
== BB_END (curr_bb
))
263 while ((insn
= NEXT_INSN (insn
)) != NULL_RTX
)
265 if (NONJUMP_INSN_P (insn
) || JUMP_P (insn
) || CALL_P (insn
))
268 /* No other active insn all the way to the end of the basic block. */
269 if (insn
== BB_END (curr_bb
))
276 /* Return the basic block reached by falling though the basic block BB. */
279 block_fallthru (basic_block bb
)
281 edge e
= find_fallthru_edge (bb
->succs
);
283 return (e
) ? e
->dest
: NULL_BLOCK
;
286 /* Go through a bunch of insns, converting them to conditional
287 execution format if possible. Return TRUE if all of the non-note
288 insns were processed. */
291 cond_exec_process_insns (ce_if_block_t
*ce_info ATTRIBUTE_UNUSED
,
292 /* if block information */rtx start
,
293 /* first insn to look at */rtx end
,
294 /* last insn to look at */rtx test
,
295 /* conditional execution test */rtx prob_val
,
296 /* probability of branch taken. */int mod_ok
)
298 int must_be_last
= FALSE
;
306 for (insn
= start
; ; insn
= NEXT_INSN (insn
))
308 if (NOTE_P (insn
) || DEBUG_INSN_P (insn
))
311 gcc_assert(NONJUMP_INSN_P (insn
) || CALL_P (insn
));
313 /* Remove USE insns that get in the way. */
314 if (reload_completed
&& GET_CODE (PATTERN (insn
)) == USE
)
316 /* ??? Ug. Actually unlinking the thing is problematic,
317 given what we'd have to coordinate with our callers. */
318 SET_INSN_DELETED (insn
);
322 /* Last insn wasn't last? */
326 if (modified_in_p (test
, insn
))
333 /* Now build the conditional form of the instruction. */
334 pattern
= PATTERN (insn
);
335 xtest
= copy_rtx (test
);
337 /* If this is already a COND_EXEC, rewrite the test to be an AND of the
339 if (GET_CODE (pattern
) == COND_EXEC
)
341 if (GET_MODE (xtest
) != GET_MODE (COND_EXEC_TEST (pattern
)))
344 xtest
= gen_rtx_AND (GET_MODE (xtest
), xtest
,
345 COND_EXEC_TEST (pattern
));
346 pattern
= COND_EXEC_CODE (pattern
);
349 pattern
= gen_rtx_COND_EXEC (VOIDmode
, xtest
, pattern
);
351 /* If the machine needs to modify the insn being conditionally executed,
352 say for example to force a constant integer operand into a temp
353 register, do so here. */
354 #ifdef IFCVT_MODIFY_INSN
355 IFCVT_MODIFY_INSN (ce_info
, pattern
, insn
);
360 validate_change (insn
, &PATTERN (insn
), pattern
, 1);
362 if (CALL_P (insn
) && prob_val
)
363 validate_change (insn
, ®_NOTES (insn
),
364 alloc_EXPR_LIST (REG_BR_PROB
, prob_val
,
365 REG_NOTES (insn
)), 1);
375 /* Return the condition for a jump. Do not do any special processing. */
378 cond_exec_get_condition (rtx jump
)
382 if (any_condjump_p (jump
))
383 test_if
= SET_SRC (pc_set (jump
));
386 cond
= XEXP (test_if
, 0);
388 /* If this branches to JUMP_LABEL when the condition is false,
389 reverse the condition. */
390 if (GET_CODE (XEXP (test_if
, 2)) == LABEL_REF
391 && XEXP (XEXP (test_if
, 2), 0) == JUMP_LABEL (jump
))
393 enum rtx_code rev
= reversed_comparison_code (cond
, jump
);
397 cond
= gen_rtx_fmt_ee (rev
, GET_MODE (cond
), XEXP (cond
, 0),
404 /* Given a simple IF-THEN or IF-THEN-ELSE block, attempt to convert it
405 to conditional execution. Return TRUE if we were successful at
406 converting the block. */
409 cond_exec_process_if_block (ce_if_block_t
* ce_info
,
410 /* if block information */int do_multiple_p
)
412 basic_block test_bb
= ce_info
->test_bb
; /* last test block */
413 basic_block then_bb
= ce_info
->then_bb
; /* THEN */
414 basic_block else_bb
= ce_info
->else_bb
; /* ELSE or NULL */
415 rtx test_expr
; /* expression in IF_THEN_ELSE that is tested */
416 rtx then_start
; /* first insn in THEN block */
417 rtx then_end
; /* last insn + 1 in THEN block */
418 rtx else_start
= NULL_RTX
; /* first insn in ELSE block or NULL */
419 rtx else_end
= NULL_RTX
; /* last insn + 1 in ELSE block */
420 int max
; /* max # of insns to convert. */
421 int then_mod_ok
; /* whether conditional mods are ok in THEN */
422 rtx true_expr
; /* test for else block insns */
423 rtx false_expr
; /* test for then block insns */
424 rtx true_prob_val
; /* probability of else block */
425 rtx false_prob_val
; /* probability of then block */
426 rtx then_last_head
= NULL_RTX
; /* Last match at the head of THEN */
427 rtx else_last_head
= NULL_RTX
; /* Last match at the head of ELSE */
428 rtx then_first_tail
= NULL_RTX
; /* First match at the tail of THEN */
429 rtx else_first_tail
= NULL_RTX
; /* First match at the tail of ELSE */
430 int then_n_insns
, else_n_insns
, n_insns
;
431 enum rtx_code false_code
;
433 /* If test is comprised of && or || elements, and we've failed at handling
434 all of them together, just use the last test if it is the special case of
435 && elements without an ELSE block. */
436 if (!do_multiple_p
&& ce_info
->num_multiple_test_blocks
)
438 if (else_bb
|| ! ce_info
->and_and_p
)
441 ce_info
->test_bb
= test_bb
= ce_info
->last_test_bb
;
442 ce_info
->num_multiple_test_blocks
= 0;
443 ce_info
->num_and_and_blocks
= 0;
444 ce_info
->num_or_or_blocks
= 0;
447 /* Find the conditional jump to the ELSE or JOIN part, and isolate
449 test_expr
= cond_exec_get_condition (BB_END (test_bb
));
453 /* If the conditional jump is more than just a conditional jump,
454 then we can not do conditional execution conversion on this block. */
455 if (! onlyjump_p (BB_END (test_bb
)))
458 /* Collect the bounds of where we're to search, skipping any labels, jumps
459 and notes at the beginning and end of the block. Then count the total
460 number of insns and see if it is small enough to convert. */
461 then_start
= first_active_insn (then_bb
);
462 then_end
= last_active_insn (then_bb
, TRUE
);
463 then_n_insns
= ce_info
->num_then_insns
= count_bb_insns (then_bb
);
464 n_insns
= then_n_insns
;
465 max
= MAX_CONDITIONAL_EXECUTE
;
472 else_start
= first_active_insn (else_bb
);
473 else_end
= last_active_insn (else_bb
, TRUE
);
474 else_n_insns
= ce_info
->num_else_insns
= count_bb_insns (else_bb
);
475 n_insns
+= else_n_insns
;
477 /* Look for matching sequences at the head and tail of the two blocks,
478 and limit the range of insns to be converted if possible. */
479 n_matching
= flow_find_cross_jump (then_bb
, else_bb
,
480 &then_first_tail
, &else_first_tail
);
481 if (then_first_tail
== BB_HEAD (then_bb
))
482 then_start
= then_end
= NULL_RTX
;
483 if (else_first_tail
== BB_HEAD (else_bb
))
484 else_start
= else_end
= NULL_RTX
;
489 then_end
= find_active_insn_before (then_bb
, then_first_tail
);
491 else_end
= find_active_insn_before (else_bb
, else_first_tail
);
492 n_insns
-= 2 * n_matching
;
495 if (then_start
&& else_start
)
497 int longest_match
= MIN (then_n_insns
- n_matching
,
498 else_n_insns
- n_matching
);
500 = flow_find_head_matching_sequence (then_bb
, else_bb
,
509 /* We won't pass the insns in the head sequence to
510 cond_exec_process_insns, so we need to test them here
511 to make sure that they don't clobber the condition. */
512 for (insn
= BB_HEAD (then_bb
);
513 insn
!= NEXT_INSN (then_last_head
);
514 insn
= NEXT_INSN (insn
))
515 if (!LABEL_P (insn
) && !NOTE_P (insn
)
516 && !DEBUG_INSN_P (insn
)
517 && modified_in_p (test_expr
, insn
))
521 if (then_last_head
== then_end
)
522 then_start
= then_end
= NULL_RTX
;
523 if (else_last_head
== else_end
)
524 else_start
= else_end
= NULL_RTX
;
529 then_start
= find_active_insn_after (then_bb
, then_last_head
);
531 else_start
= find_active_insn_after (else_bb
, else_last_head
);
532 n_insns
-= 2 * n_matching
;
540 /* Map test_expr/test_jump into the appropriate MD tests to use on
541 the conditionally executed code. */
543 true_expr
= test_expr
;
545 false_code
= reversed_comparison_code (true_expr
, BB_END (test_bb
));
546 if (false_code
!= UNKNOWN
)
547 false_expr
= gen_rtx_fmt_ee (false_code
, GET_MODE (true_expr
),
548 XEXP (true_expr
, 0), XEXP (true_expr
, 1));
550 false_expr
= NULL_RTX
;
552 #ifdef IFCVT_MODIFY_TESTS
553 /* If the machine description needs to modify the tests, such as setting a
554 conditional execution register from a comparison, it can do so here. */
555 IFCVT_MODIFY_TESTS (ce_info
, true_expr
, false_expr
);
557 /* See if the conversion failed. */
558 if (!true_expr
|| !false_expr
)
562 true_prob_val
= find_reg_note (BB_END (test_bb
), REG_BR_PROB
, NULL_RTX
);
565 true_prob_val
= XEXP (true_prob_val
, 0);
566 false_prob_val
= GEN_INT (REG_BR_PROB_BASE
- INTVAL (true_prob_val
));
569 false_prob_val
= NULL_RTX
;
571 /* If we have && or || tests, do them here. These tests are in the adjacent
572 blocks after the first block containing the test. */
573 if (ce_info
->num_multiple_test_blocks
> 0)
575 basic_block bb
= test_bb
;
576 basic_block last_test_bb
= ce_info
->last_test_bb
;
585 enum rtx_code f_code
;
587 bb
= block_fallthru (bb
);
588 start
= first_active_insn (bb
);
589 end
= last_active_insn (bb
, TRUE
);
591 && ! cond_exec_process_insns (ce_info
, start
, end
, false_expr
,
592 false_prob_val
, FALSE
))
595 /* If the conditional jump is more than just a conditional jump, then
596 we can not do conditional execution conversion on this block. */
597 if (! onlyjump_p (BB_END (bb
)))
600 /* Find the conditional jump and isolate the test. */
601 t
= cond_exec_get_condition (BB_END (bb
));
605 f_code
= reversed_comparison_code (t
, BB_END (bb
));
606 if (f_code
== UNKNOWN
)
609 f
= gen_rtx_fmt_ee (f_code
, GET_MODE (t
), XEXP (t
, 0), XEXP (t
, 1));
610 if (ce_info
->and_and_p
)
612 t
= gen_rtx_AND (GET_MODE (t
), true_expr
, t
);
613 f
= gen_rtx_IOR (GET_MODE (t
), false_expr
, f
);
617 t
= gen_rtx_IOR (GET_MODE (t
), true_expr
, t
);
618 f
= gen_rtx_AND (GET_MODE (t
), false_expr
, f
);
621 /* If the machine description needs to modify the tests, such as
622 setting a conditional execution register from a comparison, it can
624 #ifdef IFCVT_MODIFY_MULTIPLE_TESTS
625 IFCVT_MODIFY_MULTIPLE_TESTS (ce_info
, bb
, t
, f
);
627 /* See if the conversion failed. */
635 while (bb
!= last_test_bb
);
638 /* For IF-THEN-ELSE blocks, we don't allow modifications of the test
639 on then THEN block. */
640 then_mod_ok
= (else_bb
== NULL_BLOCK
);
642 /* Go through the THEN and ELSE blocks converting the insns if possible
643 to conditional execution. */
647 || ! cond_exec_process_insns (ce_info
, then_start
, then_end
,
648 false_expr
, false_prob_val
,
652 if (else_bb
&& else_end
653 && ! cond_exec_process_insns (ce_info
, else_start
, else_end
,
654 true_expr
, true_prob_val
, TRUE
))
657 /* If we cannot apply the changes, fail. Do not go through the normal fail
658 processing, since apply_change_group will call cancel_changes. */
659 if (! apply_change_group ())
661 #ifdef IFCVT_MODIFY_CANCEL
662 /* Cancel any machine dependent changes. */
663 IFCVT_MODIFY_CANCEL (ce_info
);
668 #ifdef IFCVT_MODIFY_FINAL
669 /* Do any machine dependent final modifications. */
670 IFCVT_MODIFY_FINAL (ce_info
);
673 /* Conversion succeeded. */
675 fprintf (dump_file
, "%d insn%s converted to conditional execution.\n",
676 n_insns
, (n_insns
== 1) ? " was" : "s were");
678 /* Merge the blocks! If we had matching sequences, make sure to delete one
679 copy at the appropriate location first: delete the copy in the THEN branch
680 for a tail sequence so that the remaining one is executed last for both
681 branches, and delete the copy in the ELSE branch for a head sequence so
682 that the remaining one is executed first for both branches. */
685 rtx from
= then_first_tail
;
687 from
= find_active_insn_after (then_bb
, from
);
688 delete_insn_chain (from
, BB_END (then_bb
), false);
691 delete_insn_chain (first_active_insn (else_bb
), else_last_head
, false);
693 merge_if_block (ce_info
);
694 cond_exec_changed_p
= TRUE
;
698 #ifdef IFCVT_MODIFY_CANCEL
699 /* Cancel any machine dependent changes. */
700 IFCVT_MODIFY_CANCEL (ce_info
);
707 /* Used by noce_process_if_block to communicate with its subroutines.
709 The subroutines know that A and B may be evaluated freely. They
710 know that X is a register. They should insert new instructions
711 before cond_earliest. */
715 /* The basic blocks that make up the IF-THEN-{ELSE-,}JOIN block. */
716 basic_block test_bb
, then_bb
, else_bb
, join_bb
;
718 /* The jump that ends TEST_BB. */
721 /* The jump condition. */
724 /* New insns should be inserted before this one. */
727 /* Insns in the THEN and ELSE block. There is always just this
728 one insns in those blocks. The insns are single_set insns.
729 If there was no ELSE block, INSN_B is the last insn before
730 COND_EARLIEST, or NULL_RTX. In the former case, the insn
731 operands are still valid, as if INSN_B was moved down below
735 /* The SET_SRC of INSN_A and INSN_B. */
738 /* The SET_DEST of INSN_A. */
741 /* True if this if block is not canonical. In the canonical form of
742 if blocks, the THEN_BB is the block reached via the fallthru edge
743 from TEST_BB. For the noce transformations, we allow the symmetric
745 bool then_else_reversed
;
747 /* Estimated cost of the particular branch instruction. */
751 static rtx
noce_emit_store_flag (struct noce_if_info
*, rtx
, int, int);
752 static int noce_try_move (struct noce_if_info
*);
753 static int noce_try_store_flag (struct noce_if_info
*);
754 static int noce_try_addcc (struct noce_if_info
*);
755 static int noce_try_store_flag_constants (struct noce_if_info
*);
756 static int noce_try_store_flag_mask (struct noce_if_info
*);
757 static rtx
noce_emit_cmove (struct noce_if_info
*, rtx
, enum rtx_code
, rtx
,
759 static int noce_try_cmove (struct noce_if_info
*);
760 static int noce_try_cmove_arith (struct noce_if_info
*);
761 static rtx
noce_get_alt_condition (struct noce_if_info
*, rtx
, rtx
*);
762 static int noce_try_minmax (struct noce_if_info
*);
763 static int noce_try_abs (struct noce_if_info
*);
764 static int noce_try_sign_mask (struct noce_if_info
*);
766 /* Helper function for noce_try_store_flag*. */
769 noce_emit_store_flag (struct noce_if_info
*if_info
, rtx x
, int reversep
,
772 rtx cond
= if_info
->cond
;
776 cond_complex
= (! general_operand (XEXP (cond
, 0), VOIDmode
)
777 || ! general_operand (XEXP (cond
, 1), VOIDmode
));
779 /* If earliest == jump, or when the condition is complex, try to
780 build the store_flag insn directly. */
784 rtx set
= pc_set (if_info
->jump
);
785 cond
= XEXP (SET_SRC (set
), 0);
786 if (GET_CODE (XEXP (SET_SRC (set
), 2)) == LABEL_REF
787 && XEXP (XEXP (SET_SRC (set
), 2), 0) == JUMP_LABEL (if_info
->jump
))
788 reversep
= !reversep
;
789 if (if_info
->then_else_reversed
)
790 reversep
= !reversep
;
794 code
= reversed_comparison_code (cond
, if_info
->jump
);
796 code
= GET_CODE (cond
);
798 if ((if_info
->cond_earliest
== if_info
->jump
|| cond_complex
)
799 && (normalize
== 0 || STORE_FLAG_VALUE
== normalize
))
803 tmp
= gen_rtx_fmt_ee (code
, GET_MODE (x
), XEXP (cond
, 0),
805 tmp
= gen_rtx_SET (VOIDmode
, x
, tmp
);
808 tmp
= emit_insn (tmp
);
810 if (recog_memoized (tmp
) >= 0)
816 if_info
->cond_earliest
= if_info
->jump
;
824 /* Don't even try if the comparison operands or the mode of X are weird. */
825 if (cond_complex
|| !SCALAR_INT_MODE_P (GET_MODE (x
)))
828 return emit_store_flag (x
, code
, XEXP (cond
, 0),
829 XEXP (cond
, 1), VOIDmode
,
830 (code
== LTU
|| code
== LEU
831 || code
== GEU
|| code
== GTU
), normalize
);
834 /* Emit instruction to move an rtx, possibly into STRICT_LOW_PART.
835 X is the destination/target and Y is the value to copy. */
838 noce_emit_move_insn (rtx x
, rtx y
)
840 enum machine_mode outmode
;
844 if (GET_CODE (x
) != STRICT_LOW_PART
)
846 rtx seq
, insn
, target
;
850 /* Check that the SET_SRC is reasonable before calling emit_move_insn,
851 otherwise construct a suitable SET pattern ourselves. */
852 insn
= (OBJECT_P (y
) || CONSTANT_P (y
) || GET_CODE (y
) == SUBREG
)
853 ? emit_move_insn (x
, y
)
854 : emit_insn (gen_rtx_SET (VOIDmode
, x
, y
));
858 if (recog_memoized (insn
) <= 0)
860 if (GET_CODE (x
) == ZERO_EXTRACT
)
862 rtx op
= XEXP (x
, 0);
863 unsigned HOST_WIDE_INT size
= INTVAL (XEXP (x
, 1));
864 unsigned HOST_WIDE_INT start
= INTVAL (XEXP (x
, 2));
866 /* store_bit_field expects START to be relative to
867 BYTES_BIG_ENDIAN and adjusts this value for machines with
868 BITS_BIG_ENDIAN != BYTES_BIG_ENDIAN. In order to be able to
869 invoke store_bit_field again it is necessary to have the START
870 value from the first call. */
871 if (BITS_BIG_ENDIAN
!= BYTES_BIG_ENDIAN
)
874 start
= BITS_PER_UNIT
- start
- size
;
877 gcc_assert (REG_P (op
));
878 start
= BITS_PER_WORD
- start
- size
;
882 gcc_assert (start
< (MEM_P (op
) ? BITS_PER_UNIT
: BITS_PER_WORD
));
883 store_bit_field (op
, size
, start
, GET_MODE (x
), y
);
887 switch (GET_RTX_CLASS (GET_CODE (y
)))
890 ot
= code_to_optab
[GET_CODE (y
)];
894 target
= expand_unop (GET_MODE (y
), ot
, XEXP (y
, 0), x
, 0);
895 if (target
!= NULL_RTX
)
898 emit_move_insn (x
, target
);
907 ot
= code_to_optab
[GET_CODE (y
)];
911 target
= expand_binop (GET_MODE (y
), ot
,
912 XEXP (y
, 0), XEXP (y
, 1),
914 if (target
!= NULL_RTX
)
917 emit_move_insn (x
, target
);
934 inner
= XEXP (outer
, 0);
935 outmode
= GET_MODE (outer
);
936 bitpos
= SUBREG_BYTE (outer
) * BITS_PER_UNIT
;
937 store_bit_field (inner
, GET_MODE_BITSIZE (outmode
), bitpos
, outmode
, y
);
940 /* Return sequence of instructions generated by if conversion. This
941 function calls end_sequence() to end the current stream, ensures
942 that are instructions are unshared, recognizable non-jump insns.
943 On failure, this function returns a NULL_RTX. */
946 end_ifcvt_sequence (struct noce_if_info
*if_info
)
949 rtx seq
= get_insns ();
951 set_used_flags (if_info
->x
);
952 set_used_flags (if_info
->cond
);
953 unshare_all_rtl_in_chain (seq
);
956 /* Make sure that all of the instructions emitted are recognizable,
957 and that we haven't introduced a new jump instruction.
958 As an exercise for the reader, build a general mechanism that
959 allows proper placement of required clobbers. */
960 for (insn
= seq
; insn
; insn
= NEXT_INSN (insn
))
962 || recog_memoized (insn
) == -1)
968 /* Convert "if (a != b) x = a; else x = b" into "x = a" and
969 "if (a == b) x = a; else x = b" into "x = b". */
972 noce_try_move (struct noce_if_info
*if_info
)
974 rtx cond
= if_info
->cond
;
975 enum rtx_code code
= GET_CODE (cond
);
978 if (code
!= NE
&& code
!= EQ
)
981 /* This optimization isn't valid if either A or B could be a NaN
983 if (HONOR_NANS (GET_MODE (if_info
->x
))
984 || HONOR_SIGNED_ZEROS (GET_MODE (if_info
->x
)))
987 /* Check whether the operands of the comparison are A and in
989 if ((rtx_equal_p (if_info
->a
, XEXP (cond
, 0))
990 && rtx_equal_p (if_info
->b
, XEXP (cond
, 1)))
991 || (rtx_equal_p (if_info
->a
, XEXP (cond
, 1))
992 && rtx_equal_p (if_info
->b
, XEXP (cond
, 0))))
994 y
= (code
== EQ
) ? if_info
->a
: if_info
->b
;
996 /* Avoid generating the move if the source is the destination. */
997 if (! rtx_equal_p (if_info
->x
, y
))
1000 noce_emit_move_insn (if_info
->x
, y
);
1001 seq
= end_ifcvt_sequence (if_info
);
1005 emit_insn_before_setloc (seq
, if_info
->jump
,
1006 INSN_LOCATOR (if_info
->insn_a
));
1013 /* Convert "if (test) x = 1; else x = 0".
1015 Only try 0 and STORE_FLAG_VALUE here. Other combinations will be
1016 tried in noce_try_store_flag_constants after noce_try_cmove has had
1017 a go at the conversion. */
1020 noce_try_store_flag (struct noce_if_info
*if_info
)
1025 if (CONST_INT_P (if_info
->b
)
1026 && INTVAL (if_info
->b
) == STORE_FLAG_VALUE
1027 && if_info
->a
== const0_rtx
)
1029 else if (if_info
->b
== const0_rtx
1030 && CONST_INT_P (if_info
->a
)
1031 && INTVAL (if_info
->a
) == STORE_FLAG_VALUE
1032 && (reversed_comparison_code (if_info
->cond
, if_info
->jump
)
1040 target
= noce_emit_store_flag (if_info
, if_info
->x
, reversep
, 0);
1043 if (target
!= if_info
->x
)
1044 noce_emit_move_insn (if_info
->x
, target
);
1046 seq
= end_ifcvt_sequence (if_info
);
1050 emit_insn_before_setloc (seq
, if_info
->jump
,
1051 INSN_LOCATOR (if_info
->insn_a
));
1061 /* Convert "if (test) x = a; else x = b", for A and B constant. */
1064 noce_try_store_flag_constants (struct noce_if_info
*if_info
)
1068 HOST_WIDE_INT itrue
, ifalse
, diff
, tmp
;
1069 int normalize
, can_reverse
;
1070 enum machine_mode mode
;
1072 if (CONST_INT_P (if_info
->a
)
1073 && CONST_INT_P (if_info
->b
))
1075 mode
= GET_MODE (if_info
->x
);
1076 ifalse
= INTVAL (if_info
->a
);
1077 itrue
= INTVAL (if_info
->b
);
1079 /* Make sure we can represent the difference between the two values. */
1080 if ((itrue
- ifalse
> 0)
1081 != ((ifalse
< 0) != (itrue
< 0) ? ifalse
< 0 : ifalse
< itrue
))
1084 diff
= trunc_int_for_mode (itrue
- ifalse
, mode
);
1086 can_reverse
= (reversed_comparison_code (if_info
->cond
, if_info
->jump
)
1090 if (diff
== STORE_FLAG_VALUE
|| diff
== -STORE_FLAG_VALUE
)
1092 else if (ifalse
== 0 && exact_log2 (itrue
) >= 0
1093 && (STORE_FLAG_VALUE
== 1
1094 || if_info
->branch_cost
>= 2))
1096 else if (itrue
== 0 && exact_log2 (ifalse
) >= 0 && can_reverse
1097 && (STORE_FLAG_VALUE
== 1 || if_info
->branch_cost
>= 2))
1098 normalize
= 1, reversep
= 1;
1099 else if (itrue
== -1
1100 && (STORE_FLAG_VALUE
== -1
1101 || if_info
->branch_cost
>= 2))
1103 else if (ifalse
== -1 && can_reverse
1104 && (STORE_FLAG_VALUE
== -1 || if_info
->branch_cost
>= 2))
1105 normalize
= -1, reversep
= 1;
1106 else if ((if_info
->branch_cost
>= 2 && STORE_FLAG_VALUE
== -1)
1107 || if_info
->branch_cost
>= 3)
1114 tmp
= itrue
; itrue
= ifalse
; ifalse
= tmp
;
1115 diff
= trunc_int_for_mode (-diff
, mode
);
1119 target
= noce_emit_store_flag (if_info
, if_info
->x
, reversep
, normalize
);
1126 /* if (test) x = 3; else x = 4;
1127 => x = 3 + (test == 0); */
1128 if (diff
== STORE_FLAG_VALUE
|| diff
== -STORE_FLAG_VALUE
)
1130 target
= expand_simple_binop (mode
,
1131 (diff
== STORE_FLAG_VALUE
1133 GEN_INT (ifalse
), target
, if_info
->x
, 0,
1137 /* if (test) x = 8; else x = 0;
1138 => x = (test != 0) << 3; */
1139 else if (ifalse
== 0 && (tmp
= exact_log2 (itrue
)) >= 0)
1141 target
= expand_simple_binop (mode
, ASHIFT
,
1142 target
, GEN_INT (tmp
), if_info
->x
, 0,
1146 /* if (test) x = -1; else x = b;
1147 => x = -(test != 0) | b; */
1148 else if (itrue
== -1)
1150 target
= expand_simple_binop (mode
, IOR
,
1151 target
, GEN_INT (ifalse
), if_info
->x
, 0,
1155 /* if (test) x = a; else x = b;
1156 => x = (-(test != 0) & (b - a)) + a; */
1159 target
= expand_simple_binop (mode
, AND
,
1160 target
, GEN_INT (diff
), if_info
->x
, 0,
1163 target
= expand_simple_binop (mode
, PLUS
,
1164 target
, GEN_INT (ifalse
),
1165 if_info
->x
, 0, OPTAB_WIDEN
);
1174 if (target
!= if_info
->x
)
1175 noce_emit_move_insn (if_info
->x
, target
);
1177 seq
= end_ifcvt_sequence (if_info
);
1181 emit_insn_before_setloc (seq
, if_info
->jump
,
1182 INSN_LOCATOR (if_info
->insn_a
));
1189 /* Convert "if (test) foo++" into "foo += (test != 0)", and
1190 similarly for "foo--". */
1193 noce_try_addcc (struct noce_if_info
*if_info
)
1196 int subtract
, normalize
;
1198 if (GET_CODE (if_info
->a
) == PLUS
1199 && rtx_equal_p (XEXP (if_info
->a
, 0), if_info
->b
)
1200 && (reversed_comparison_code (if_info
->cond
, if_info
->jump
)
1203 rtx cond
= if_info
->cond
;
1204 enum rtx_code code
= reversed_comparison_code (cond
, if_info
->jump
);
1206 /* First try to use addcc pattern. */
1207 if (general_operand (XEXP (cond
, 0), VOIDmode
)
1208 && general_operand (XEXP (cond
, 1), VOIDmode
))
1211 target
= emit_conditional_add (if_info
->x
, code
,
1216 XEXP (if_info
->a
, 1),
1217 GET_MODE (if_info
->x
),
1218 (code
== LTU
|| code
== GEU
1219 || code
== LEU
|| code
== GTU
));
1222 if (target
!= if_info
->x
)
1223 noce_emit_move_insn (if_info
->x
, target
);
1225 seq
= end_ifcvt_sequence (if_info
);
1229 emit_insn_before_setloc (seq
, if_info
->jump
,
1230 INSN_LOCATOR (if_info
->insn_a
));
1236 /* If that fails, construct conditional increment or decrement using
1238 if (if_info
->branch_cost
>= 2
1239 && (XEXP (if_info
->a
, 1) == const1_rtx
1240 || XEXP (if_info
->a
, 1) == constm1_rtx
))
1243 if (STORE_FLAG_VALUE
== INTVAL (XEXP (if_info
->a
, 1)))
1244 subtract
= 0, normalize
= 0;
1245 else if (-STORE_FLAG_VALUE
== INTVAL (XEXP (if_info
->a
, 1)))
1246 subtract
= 1, normalize
= 0;
1248 subtract
= 0, normalize
= INTVAL (XEXP (if_info
->a
, 1));
1251 target
= noce_emit_store_flag (if_info
,
1252 gen_reg_rtx (GET_MODE (if_info
->x
)),
1256 target
= expand_simple_binop (GET_MODE (if_info
->x
),
1257 subtract
? MINUS
: PLUS
,
1258 if_info
->b
, target
, if_info
->x
,
1262 if (target
!= if_info
->x
)
1263 noce_emit_move_insn (if_info
->x
, target
);
1265 seq
= end_ifcvt_sequence (if_info
);
1269 emit_insn_before_setloc (seq
, if_info
->jump
,
1270 INSN_LOCATOR (if_info
->insn_a
));
1280 /* Convert "if (test) x = 0;" to "x &= -(test == 0);" */
1283 noce_try_store_flag_mask (struct noce_if_info
*if_info
)
1289 if ((if_info
->branch_cost
>= 2
1290 || STORE_FLAG_VALUE
== -1)
1291 && ((if_info
->a
== const0_rtx
1292 && rtx_equal_p (if_info
->b
, if_info
->x
))
1293 || ((reversep
= (reversed_comparison_code (if_info
->cond
,
1296 && if_info
->b
== const0_rtx
1297 && rtx_equal_p (if_info
->a
, if_info
->x
))))
1300 target
= noce_emit_store_flag (if_info
,
1301 gen_reg_rtx (GET_MODE (if_info
->x
)),
1304 target
= expand_simple_binop (GET_MODE (if_info
->x
), AND
,
1306 target
, if_info
->x
, 0,
1311 if (target
!= if_info
->x
)
1312 noce_emit_move_insn (if_info
->x
, target
);
1314 seq
= end_ifcvt_sequence (if_info
);
1318 emit_insn_before_setloc (seq
, if_info
->jump
,
1319 INSN_LOCATOR (if_info
->insn_a
));
1329 /* Helper function for noce_try_cmove and noce_try_cmove_arith. */
1332 noce_emit_cmove (struct noce_if_info
*if_info
, rtx x
, enum rtx_code code
,
1333 rtx cmp_a
, rtx cmp_b
, rtx vfalse
, rtx vtrue
)
1338 /* If earliest == jump, try to build the cmove insn directly.
1339 This is helpful when combine has created some complex condition
1340 (like for alpha's cmovlbs) that we can't hope to regenerate
1341 through the normal interface. */
1343 if (if_info
->cond_earliest
== if_info
->jump
)
1347 tmp
= gen_rtx_fmt_ee (code
, GET_MODE (if_info
->cond
), cmp_a
, cmp_b
);
1348 tmp
= gen_rtx_IF_THEN_ELSE (GET_MODE (x
), tmp
, vtrue
, vfalse
);
1349 tmp
= gen_rtx_SET (VOIDmode
, x
, tmp
);
1352 tmp
= emit_insn (tmp
);
1354 if (recog_memoized (tmp
) >= 0)
1366 /* Don't even try if the comparison operands are weird. */
1367 if (! general_operand (cmp_a
, GET_MODE (cmp_a
))
1368 || ! general_operand (cmp_b
, GET_MODE (cmp_b
)))
1371 #if HAVE_conditional_move
1372 unsignedp
= (code
== LTU
|| code
== GEU
1373 || code
== LEU
|| code
== GTU
);
1375 target
= emit_conditional_move (x
, code
, cmp_a
, cmp_b
, VOIDmode
,
1376 vtrue
, vfalse
, GET_MODE (x
),
1381 /* We might be faced with a situation like:
1384 vtrue = (subreg:M (reg:N VTRUE) BYTE)
1385 vfalse = (subreg:M (reg:N VFALSE) BYTE)
1387 We can't do a conditional move in mode M, but it's possible that we
1388 could do a conditional move in mode N instead and take a subreg of
1391 If we can't create new pseudos, though, don't bother. */
1392 if (reload_completed
)
1395 if (GET_CODE (vtrue
) == SUBREG
&& GET_CODE (vfalse
) == SUBREG
)
1397 rtx reg_vtrue
= SUBREG_REG (vtrue
);
1398 rtx reg_vfalse
= SUBREG_REG (vfalse
);
1399 unsigned int byte_vtrue
= SUBREG_BYTE (vtrue
);
1400 unsigned int byte_vfalse
= SUBREG_BYTE (vfalse
);
1401 rtx promoted_target
;
1403 if (GET_MODE (reg_vtrue
) != GET_MODE (reg_vfalse
)
1404 || byte_vtrue
!= byte_vfalse
1405 || (SUBREG_PROMOTED_VAR_P (vtrue
)
1406 != SUBREG_PROMOTED_VAR_P (vfalse
))
1407 || (SUBREG_PROMOTED_UNSIGNED_P (vtrue
)
1408 != SUBREG_PROMOTED_UNSIGNED_P (vfalse
)))
1411 promoted_target
= gen_reg_rtx (GET_MODE (reg_vtrue
));
1413 target
= emit_conditional_move (promoted_target
, code
, cmp_a
, cmp_b
,
1414 VOIDmode
, reg_vtrue
, reg_vfalse
,
1415 GET_MODE (reg_vtrue
), unsignedp
);
1416 /* Nope, couldn't do it in that mode either. */
1420 target
= gen_rtx_SUBREG (GET_MODE (vtrue
), promoted_target
, byte_vtrue
);
1421 SUBREG_PROMOTED_VAR_P (target
) = SUBREG_PROMOTED_VAR_P (vtrue
);
1422 SUBREG_PROMOTED_UNSIGNED_SET (target
, SUBREG_PROMOTED_UNSIGNED_P (vtrue
));
1423 emit_move_insn (x
, target
);
1429 /* We'll never get here, as noce_process_if_block doesn't call the
1430 functions involved. Ifdef code, however, should be discouraged
1431 because it leads to typos in the code not selected. However,
1432 emit_conditional_move won't exist either. */
1437 /* Try only simple constants and registers here. More complex cases
1438 are handled in noce_try_cmove_arith after noce_try_store_flag_arith
1439 has had a go at it. */
1442 noce_try_cmove (struct noce_if_info
*if_info
)
1447 if ((CONSTANT_P (if_info
->a
) || register_operand (if_info
->a
, VOIDmode
))
1448 && (CONSTANT_P (if_info
->b
) || register_operand (if_info
->b
, VOIDmode
)))
1452 code
= GET_CODE (if_info
->cond
);
1453 target
= noce_emit_cmove (if_info
, if_info
->x
, code
,
1454 XEXP (if_info
->cond
, 0),
1455 XEXP (if_info
->cond
, 1),
1456 if_info
->a
, if_info
->b
);
1460 if (target
!= if_info
->x
)
1461 noce_emit_move_insn (if_info
->x
, target
);
1463 seq
= end_ifcvt_sequence (if_info
);
1467 emit_insn_before_setloc (seq
, if_info
->jump
,
1468 INSN_LOCATOR (if_info
->insn_a
));
1481 /* Try more complex cases involving conditional_move. */
1484 noce_try_cmove_arith (struct noce_if_info
*if_info
)
1496 /* A conditional move from two memory sources is equivalent to a
1497 conditional on their addresses followed by a load. Don't do this
1498 early because it'll screw alias analysis. Note that we've
1499 already checked for no side effects. */
1500 /* ??? FIXME: Magic number 5. */
1501 if (cse_not_expected
1502 && MEM_P (a
) && MEM_P (b
)
1503 && MEM_ADDR_SPACE (a
) == MEM_ADDR_SPACE (b
)
1504 && if_info
->branch_cost
>= 5)
1506 enum machine_mode address_mode
1507 = targetm
.addr_space
.address_mode (MEM_ADDR_SPACE (a
));
1511 x
= gen_reg_rtx (address_mode
);
1515 /* ??? We could handle this if we knew that a load from A or B could
1516 not fault. This is also true if we've already loaded
1517 from the address along the path from ENTRY. */
1518 else if (may_trap_p (a
) || may_trap_p (b
))
1521 /* if (test) x = a + b; else x = c - d;
1528 code
= GET_CODE (if_info
->cond
);
1529 insn_a
= if_info
->insn_a
;
1530 insn_b
= if_info
->insn_b
;
1532 /* Total insn_rtx_cost should be smaller than branch cost. Exit
1533 if insn_rtx_cost can't be estimated. */
1537 = insn_rtx_cost (PATTERN (insn_a
),
1538 optimize_bb_for_speed_p (BLOCK_FOR_INSN (insn_a
)));
1539 if (insn_cost
== 0 || insn_cost
> COSTS_N_INSNS (if_info
->branch_cost
))
1548 += insn_rtx_cost (PATTERN (insn_b
),
1549 optimize_bb_for_speed_p (BLOCK_FOR_INSN (insn_b
)));
1550 if (insn_cost
== 0 || insn_cost
> COSTS_N_INSNS (if_info
->branch_cost
))
1554 /* Possibly rearrange operands to make things come out more natural. */
1555 if (reversed_comparison_code (if_info
->cond
, if_info
->jump
) != UNKNOWN
)
1558 if (rtx_equal_p (b
, x
))
1560 else if (general_operand (b
, GET_MODE (b
)))
1565 code
= reversed_comparison_code (if_info
->cond
, if_info
->jump
);
1566 tmp
= a
, a
= b
, b
= tmp
;
1567 tmp
= insn_a
, insn_a
= insn_b
, insn_b
= tmp
;
1576 /* If either operand is complex, load it into a register first.
1577 The best way to do this is to copy the original insn. In this
1578 way we preserve any clobbers etc that the insn may have had.
1579 This is of course not possible in the IS_MEM case. */
1580 if (! general_operand (a
, GET_MODE (a
)))
1586 tmp
= gen_reg_rtx (GET_MODE (a
));
1587 tmp
= emit_insn (gen_rtx_SET (VOIDmode
, tmp
, a
));
1590 goto end_seq_and_fail
;
1593 a
= gen_reg_rtx (GET_MODE (a
));
1594 tmp
= copy_rtx (insn_a
);
1595 set
= single_set (tmp
);
1597 tmp
= emit_insn (PATTERN (tmp
));
1599 if (recog_memoized (tmp
) < 0)
1600 goto end_seq_and_fail
;
1602 if (! general_operand (b
, GET_MODE (b
)))
1608 tmp
= gen_reg_rtx (GET_MODE (b
));
1609 tmp
= gen_rtx_SET (VOIDmode
, tmp
, b
);
1612 goto end_seq_and_fail
;
1615 b
= gen_reg_rtx (GET_MODE (b
));
1616 tmp
= copy_rtx (insn_b
);
1617 set
= single_set (tmp
);
1619 tmp
= PATTERN (tmp
);
1622 /* If insn to set up A clobbers any registers B depends on, try to
1623 swap insn that sets up A with the one that sets up B. If even
1624 that doesn't help, punt. */
1625 last
= get_last_insn ();
1626 if (last
&& modified_in_p (orig_b
, last
))
1628 tmp
= emit_insn_before (tmp
, get_insns ());
1629 if (modified_in_p (orig_a
, tmp
))
1630 goto end_seq_and_fail
;
1633 tmp
= emit_insn (tmp
);
1635 if (recog_memoized (tmp
) < 0)
1636 goto end_seq_and_fail
;
1639 target
= noce_emit_cmove (if_info
, x
, code
, XEXP (if_info
->cond
, 0),
1640 XEXP (if_info
->cond
, 1), a
, b
);
1643 goto end_seq_and_fail
;
1645 /* If we're handling a memory for above, emit the load now. */
1648 tmp
= gen_rtx_MEM (GET_MODE (if_info
->x
), target
);
1650 /* Copy over flags as appropriate. */
1651 if (MEM_VOLATILE_P (if_info
->a
) || MEM_VOLATILE_P (if_info
->b
))
1652 MEM_VOLATILE_P (tmp
) = 1;
1653 if (MEM_IN_STRUCT_P (if_info
->a
) && MEM_IN_STRUCT_P (if_info
->b
))
1654 MEM_IN_STRUCT_P (tmp
) = 1;
1655 if (MEM_SCALAR_P (if_info
->a
) && MEM_SCALAR_P (if_info
->b
))
1656 MEM_SCALAR_P (tmp
) = 1;
1657 if (MEM_ALIAS_SET (if_info
->a
) == MEM_ALIAS_SET (if_info
->b
))
1658 set_mem_alias_set (tmp
, MEM_ALIAS_SET (if_info
->a
));
1660 MIN (MEM_ALIGN (if_info
->a
), MEM_ALIGN (if_info
->b
)));
1662 gcc_assert (MEM_ADDR_SPACE (if_info
->a
) == MEM_ADDR_SPACE (if_info
->b
));
1663 set_mem_addr_space (tmp
, MEM_ADDR_SPACE (if_info
->a
));
1665 noce_emit_move_insn (if_info
->x
, tmp
);
1667 else if (target
!= x
)
1668 noce_emit_move_insn (x
, target
);
1670 tmp
= end_ifcvt_sequence (if_info
);
1674 emit_insn_before_setloc (tmp
, if_info
->jump
, INSN_LOCATOR (if_info
->insn_a
));
1682 /* For most cases, the simplified condition we found is the best
1683 choice, but this is not the case for the min/max/abs transforms.
1684 For these we wish to know that it is A or B in the condition. */
1687 noce_get_alt_condition (struct noce_if_info
*if_info
, rtx target
,
1690 rtx cond
, set
, insn
;
1693 /* If target is already mentioned in the known condition, return it. */
1694 if (reg_mentioned_p (target
, if_info
->cond
))
1696 *earliest
= if_info
->cond_earliest
;
1697 return if_info
->cond
;
1700 set
= pc_set (if_info
->jump
);
1701 cond
= XEXP (SET_SRC (set
), 0);
1703 = GET_CODE (XEXP (SET_SRC (set
), 2)) == LABEL_REF
1704 && XEXP (XEXP (SET_SRC (set
), 2), 0) == JUMP_LABEL (if_info
->jump
);
1705 if (if_info
->then_else_reversed
)
1708 /* If we're looking for a constant, try to make the conditional
1709 have that constant in it. There are two reasons why it may
1710 not have the constant we want:
1712 1. GCC may have needed to put the constant in a register, because
1713 the target can't compare directly against that constant. For
1714 this case, we look for a SET immediately before the comparison
1715 that puts a constant in that register.
1717 2. GCC may have canonicalized the conditional, for example
1718 replacing "if x < 4" with "if x <= 3". We can undo that (or
1719 make equivalent types of changes) to get the constants we need
1720 if they're off by one in the right direction. */
1722 if (CONST_INT_P (target
))
1724 enum rtx_code code
= GET_CODE (if_info
->cond
);
1725 rtx op_a
= XEXP (if_info
->cond
, 0);
1726 rtx op_b
= XEXP (if_info
->cond
, 1);
1729 /* First, look to see if we put a constant in a register. */
1730 prev_insn
= prev_nonnote_insn (if_info
->cond_earliest
);
1732 && BLOCK_FOR_INSN (prev_insn
)
1733 == BLOCK_FOR_INSN (if_info
->cond_earliest
)
1734 && INSN_P (prev_insn
)
1735 && GET_CODE (PATTERN (prev_insn
)) == SET
)
1737 rtx src
= find_reg_equal_equiv_note (prev_insn
);
1739 src
= SET_SRC (PATTERN (prev_insn
));
1740 if (CONST_INT_P (src
))
1742 if (rtx_equal_p (op_a
, SET_DEST (PATTERN (prev_insn
))))
1744 else if (rtx_equal_p (op_b
, SET_DEST (PATTERN (prev_insn
))))
1747 if (CONST_INT_P (op_a
))
1752 code
= swap_condition (code
);
1757 /* Now, look to see if we can get the right constant by
1758 adjusting the conditional. */
1759 if (CONST_INT_P (op_b
))
1761 HOST_WIDE_INT desired_val
= INTVAL (target
);
1762 HOST_WIDE_INT actual_val
= INTVAL (op_b
);
1767 if (actual_val
== desired_val
+ 1)
1770 op_b
= GEN_INT (desired_val
);
1774 if (actual_val
== desired_val
- 1)
1777 op_b
= GEN_INT (desired_val
);
1781 if (actual_val
== desired_val
- 1)
1784 op_b
= GEN_INT (desired_val
);
1788 if (actual_val
== desired_val
+ 1)
1791 op_b
= GEN_INT (desired_val
);
1799 /* If we made any changes, generate a new conditional that is
1800 equivalent to what we started with, but has the right
1802 if (code
!= GET_CODE (if_info
->cond
)
1803 || op_a
!= XEXP (if_info
->cond
, 0)
1804 || op_b
!= XEXP (if_info
->cond
, 1))
1806 cond
= gen_rtx_fmt_ee (code
, GET_MODE (cond
), op_a
, op_b
);
1807 *earliest
= if_info
->cond_earliest
;
1812 cond
= canonicalize_condition (if_info
->jump
, cond
, reverse
,
1813 earliest
, target
, false, true);
1814 if (! cond
|| ! reg_mentioned_p (target
, cond
))
1817 /* We almost certainly searched back to a different place.
1818 Need to re-verify correct lifetimes. */
1820 /* X may not be mentioned in the range (cond_earliest, jump]. */
1821 for (insn
= if_info
->jump
; insn
!= *earliest
; insn
= PREV_INSN (insn
))
1822 if (INSN_P (insn
) && reg_overlap_mentioned_p (if_info
->x
, PATTERN (insn
)))
1825 /* A and B may not be modified in the range [cond_earliest, jump). */
1826 for (insn
= *earliest
; insn
!= if_info
->jump
; insn
= NEXT_INSN (insn
))
1828 && (modified_in_p (if_info
->a
, insn
)
1829 || modified_in_p (if_info
->b
, insn
)))
1835 /* Convert "if (a < b) x = a; else x = b;" to "x = min(a, b);", etc. */
1838 noce_try_minmax (struct noce_if_info
*if_info
)
1840 rtx cond
, earliest
, target
, seq
;
1841 enum rtx_code code
, op
;
1844 /* ??? Reject modes with NaNs or signed zeros since we don't know how
1845 they will be resolved with an SMIN/SMAX. It wouldn't be too hard
1846 to get the target to tell us... */
1847 if (HONOR_SIGNED_ZEROS (GET_MODE (if_info
->x
))
1848 || HONOR_NANS (GET_MODE (if_info
->x
)))
1851 cond
= noce_get_alt_condition (if_info
, if_info
->a
, &earliest
);
1855 /* Verify the condition is of the form we expect, and canonicalize
1856 the comparison code. */
1857 code
= GET_CODE (cond
);
1858 if (rtx_equal_p (XEXP (cond
, 0), if_info
->a
))
1860 if (! rtx_equal_p (XEXP (cond
, 1), if_info
->b
))
1863 else if (rtx_equal_p (XEXP (cond
, 1), if_info
->a
))
1865 if (! rtx_equal_p (XEXP (cond
, 0), if_info
->b
))
1867 code
= swap_condition (code
);
1872 /* Determine what sort of operation this is. Note that the code is for
1873 a taken branch, so the code->operation mapping appears backwards. */
1906 target
= expand_simple_binop (GET_MODE (if_info
->x
), op
,
1907 if_info
->a
, if_info
->b
,
1908 if_info
->x
, unsignedp
, OPTAB_WIDEN
);
1914 if (target
!= if_info
->x
)
1915 noce_emit_move_insn (if_info
->x
, target
);
1917 seq
= end_ifcvt_sequence (if_info
);
1921 emit_insn_before_setloc (seq
, if_info
->jump
, INSN_LOCATOR (if_info
->insn_a
));
1922 if_info
->cond
= cond
;
1923 if_info
->cond_earliest
= earliest
;
1928 /* Convert "if (a < 0) x = -a; else x = a;" to "x = abs(a);",
1929 "if (a < 0) x = ~a; else x = a;" to "x = one_cmpl_abs(a);",
1933 noce_try_abs (struct noce_if_info
*if_info
)
1935 rtx cond
, earliest
, target
, seq
, a
, b
, c
;
1937 bool one_cmpl
= false;
1939 /* Reject modes with signed zeros. */
1940 if (HONOR_SIGNED_ZEROS (GET_MODE (if_info
->x
)))
1943 /* Recognize A and B as constituting an ABS or NABS. The canonical
1944 form is a branch around the negation, taken when the object is the
1945 first operand of a comparison against 0 that evaluates to true. */
1948 if (GET_CODE (a
) == NEG
&& rtx_equal_p (XEXP (a
, 0), b
))
1950 else if (GET_CODE (b
) == NEG
&& rtx_equal_p (XEXP (b
, 0), a
))
1952 c
= a
; a
= b
; b
= c
;
1955 else if (GET_CODE (a
) == NOT
&& rtx_equal_p (XEXP (a
, 0), b
))
1960 else if (GET_CODE (b
) == NOT
&& rtx_equal_p (XEXP (b
, 0), a
))
1962 c
= a
; a
= b
; b
= c
;
1969 cond
= noce_get_alt_condition (if_info
, b
, &earliest
);
1973 /* Verify the condition is of the form we expect. */
1974 if (rtx_equal_p (XEXP (cond
, 0), b
))
1976 else if (rtx_equal_p (XEXP (cond
, 1), b
))
1984 /* Verify that C is zero. Search one step backward for a
1985 REG_EQUAL note or a simple source if necessary. */
1988 rtx set
, insn
= prev_nonnote_insn (earliest
);
1990 && BLOCK_FOR_INSN (insn
) == BLOCK_FOR_INSN (earliest
)
1991 && (set
= single_set (insn
))
1992 && rtx_equal_p (SET_DEST (set
), c
))
1994 rtx note
= find_reg_equal_equiv_note (insn
);
2004 && GET_CODE (XEXP (c
, 0)) == SYMBOL_REF
2005 && CONSTANT_POOL_ADDRESS_P (XEXP (c
, 0)))
2006 c
= get_pool_constant (XEXP (c
, 0));
2008 /* Work around funny ideas get_condition has wrt canonicalization.
2009 Note that these rtx constants are known to be CONST_INT, and
2010 therefore imply integer comparisons. */
2011 if (c
== constm1_rtx
&& GET_CODE (cond
) == GT
)
2013 else if (c
== const1_rtx
&& GET_CODE (cond
) == LT
)
2015 else if (c
!= CONST0_RTX (GET_MODE (b
)))
2018 /* Determine what sort of operation this is. */
2019 switch (GET_CODE (cond
))
2038 target
= expand_one_cmpl_abs_nojump (GET_MODE (if_info
->x
), b
,
2041 target
= expand_abs_nojump (GET_MODE (if_info
->x
), b
, if_info
->x
, 1);
2043 /* ??? It's a quandary whether cmove would be better here, especially
2044 for integers. Perhaps combine will clean things up. */
2045 if (target
&& negate
)
2048 target
= expand_simple_unop (GET_MODE (target
), NOT
, target
,
2051 target
= expand_simple_unop (GET_MODE (target
), NEG
, target
,
2061 if (target
!= if_info
->x
)
2062 noce_emit_move_insn (if_info
->x
, target
);
2064 seq
= end_ifcvt_sequence (if_info
);
2068 emit_insn_before_setloc (seq
, if_info
->jump
, INSN_LOCATOR (if_info
->insn_a
));
2069 if_info
->cond
= cond
;
2070 if_info
->cond_earliest
= earliest
;
2075 /* Convert "if (m < 0) x = b; else x = 0;" to "x = (m >> C) & b;". */
2078 noce_try_sign_mask (struct noce_if_info
*if_info
)
2080 rtx cond
, t
, m
, c
, seq
;
2081 enum machine_mode mode
;
2083 bool t_unconditional
;
2085 cond
= if_info
->cond
;
2086 code
= GET_CODE (cond
);
2091 if (if_info
->a
== const0_rtx
)
2093 if ((code
== LT
&& c
== const0_rtx
)
2094 || (code
== LE
&& c
== constm1_rtx
))
2097 else if (if_info
->b
== const0_rtx
)
2099 if ((code
== GE
&& c
== const0_rtx
)
2100 || (code
== GT
&& c
== constm1_rtx
))
2104 if (! t
|| side_effects_p (t
))
2107 /* We currently don't handle different modes. */
2108 mode
= GET_MODE (t
);
2109 if (GET_MODE (m
) != mode
)
2112 /* This is only profitable if T is unconditionally executed/evaluated in the
2113 original insn sequence or T is cheap. The former happens if B is the
2114 non-zero (T) value and if INSN_B was taken from TEST_BB, or there was no
2115 INSN_B which can happen for e.g. conditional stores to memory. For the
2116 cost computation use the block TEST_BB where the evaluation will end up
2117 after the transformation. */
2120 && (if_info
->insn_b
== NULL_RTX
2121 || BLOCK_FOR_INSN (if_info
->insn_b
) == if_info
->test_bb
));
2122 if (!(t_unconditional
2123 || (rtx_cost (t
, SET
, optimize_bb_for_speed_p (if_info
->test_bb
))
2124 < COSTS_N_INSNS (2))))
2128 /* Use emit_store_flag to generate "m < 0 ? -1 : 0" instead of expanding
2129 "(signed) m >> 31" directly. This benefits targets with specialized
2130 insns to obtain the signmask, but still uses ashr_optab otherwise. */
2131 m
= emit_store_flag (gen_reg_rtx (mode
), LT
, m
, const0_rtx
, mode
, 0, -1);
2132 t
= m
? expand_binop (mode
, and_optab
, m
, t
, NULL_RTX
, 0, OPTAB_DIRECT
)
2141 noce_emit_move_insn (if_info
->x
, t
);
2143 seq
= end_ifcvt_sequence (if_info
);
2147 emit_insn_before_setloc (seq
, if_info
->jump
, INSN_LOCATOR (if_info
->insn_a
));
2152 /* Optimize away "if (x & C) x |= C" and similar bit manipulation
2156 noce_try_bitop (struct noce_if_info
*if_info
)
2158 rtx cond
, x
, a
, result
, seq
;
2159 enum machine_mode mode
;
2164 cond
= if_info
->cond
;
2165 code
= GET_CODE (cond
);
2167 /* Check for no else condition. */
2168 if (! rtx_equal_p (x
, if_info
->b
))
2171 /* Check for a suitable condition. */
2172 if (code
!= NE
&& code
!= EQ
)
2174 if (XEXP (cond
, 1) != const0_rtx
)
2176 cond
= XEXP (cond
, 0);
2178 /* ??? We could also handle AND here. */
2179 if (GET_CODE (cond
) == ZERO_EXTRACT
)
2181 if (XEXP (cond
, 1) != const1_rtx
2182 || !CONST_INT_P (XEXP (cond
, 2))
2183 || ! rtx_equal_p (x
, XEXP (cond
, 0)))
2185 bitnum
= INTVAL (XEXP (cond
, 2));
2186 mode
= GET_MODE (x
);
2187 if (BITS_BIG_ENDIAN
)
2188 bitnum
= GET_MODE_BITSIZE (mode
) - 1 - bitnum
;
2189 if (bitnum
< 0 || bitnum
>= HOST_BITS_PER_WIDE_INT
)
2196 if (GET_CODE (a
) == IOR
|| GET_CODE (a
) == XOR
)
2198 /* Check for "if (X & C) x = x op C". */
2199 if (! rtx_equal_p (x
, XEXP (a
, 0))
2200 || !CONST_INT_P (XEXP (a
, 1))
2201 || (INTVAL (XEXP (a
, 1)) & GET_MODE_MASK (mode
))
2202 != (unsigned HOST_WIDE_INT
) 1 << bitnum
)
2205 /* if ((x & C) == 0) x |= C; is transformed to x |= C. */
2206 /* if ((x & C) != 0) x |= C; is transformed to nothing. */
2207 if (GET_CODE (a
) == IOR
)
2208 result
= (code
== NE
) ? a
: NULL_RTX
;
2209 else if (code
== NE
)
2211 /* if ((x & C) == 0) x ^= C; is transformed to x |= C. */
2212 result
= gen_int_mode ((HOST_WIDE_INT
) 1 << bitnum
, mode
);
2213 result
= simplify_gen_binary (IOR
, mode
, x
, result
);
2217 /* if ((x & C) != 0) x ^= C; is transformed to x &= ~C. */
2218 result
= gen_int_mode (~((HOST_WIDE_INT
) 1 << bitnum
), mode
);
2219 result
= simplify_gen_binary (AND
, mode
, x
, result
);
2222 else if (GET_CODE (a
) == AND
)
2224 /* Check for "if (X & C) x &= ~C". */
2225 if (! rtx_equal_p (x
, XEXP (a
, 0))
2226 || !CONST_INT_P (XEXP (a
, 1))
2227 || (INTVAL (XEXP (a
, 1)) & GET_MODE_MASK (mode
))
2228 != (~((HOST_WIDE_INT
) 1 << bitnum
) & GET_MODE_MASK (mode
)))
2231 /* if ((x & C) == 0) x &= ~C; is transformed to nothing. */
2232 /* if ((x & C) != 0) x &= ~C; is transformed to x &= ~C. */
2233 result
= (code
== EQ
) ? a
: NULL_RTX
;
2241 noce_emit_move_insn (x
, result
);
2242 seq
= end_ifcvt_sequence (if_info
);
2246 emit_insn_before_setloc (seq
, if_info
->jump
,
2247 INSN_LOCATOR (if_info
->insn_a
));
2253 /* Similar to get_condition, only the resulting condition must be
2254 valid at JUMP, instead of at EARLIEST.
2256 If THEN_ELSE_REVERSED is true, the fallthrough does not go to the
2257 THEN block of the caller, and we have to reverse the condition. */
2260 noce_get_condition (rtx jump
, rtx
*earliest
, bool then_else_reversed
)
2265 if (! any_condjump_p (jump
))
2268 set
= pc_set (jump
);
2270 /* If this branches to JUMP_LABEL when the condition is false,
2271 reverse the condition. */
2272 reverse
= (GET_CODE (XEXP (SET_SRC (set
), 2)) == LABEL_REF
2273 && XEXP (XEXP (SET_SRC (set
), 2), 0) == JUMP_LABEL (jump
));
2275 /* We may have to reverse because the caller's if block is not canonical,
2276 i.e. the THEN block isn't the fallthrough block for the TEST block
2277 (see find_if_header). */
2278 if (then_else_reversed
)
2281 /* If the condition variable is a register and is MODE_INT, accept it. */
2283 cond
= XEXP (SET_SRC (set
), 0);
2284 tmp
= XEXP (cond
, 0);
2285 if (REG_P (tmp
) && GET_MODE_CLASS (GET_MODE (tmp
)) == MODE_INT
)
2290 cond
= gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond
)),
2291 GET_MODE (cond
), tmp
, XEXP (cond
, 1));
2295 /* Otherwise, fall back on canonicalize_condition to do the dirty
2296 work of manipulating MODE_CC values and COMPARE rtx codes. */
2297 tmp
= canonicalize_condition (jump
, cond
, reverse
, earliest
,
2298 NULL_RTX
, false, true);
2300 /* We don't handle side-effects in the condition, like handling
2301 REG_INC notes and making sure no duplicate conditions are emitted. */
2302 if (tmp
!= NULL_RTX
&& side_effects_p (tmp
))
2308 /* Return true if OP is ok for if-then-else processing. */
2311 noce_operand_ok (const_rtx op
)
2313 /* We special-case memories, so handle any of them with
2314 no address side effects. */
2316 return ! side_effects_p (XEXP (op
, 0));
2318 if (side_effects_p (op
))
2321 return ! may_trap_p (op
);
2324 /* Return true if a write into MEM may trap or fault. */
2327 noce_mem_write_may_trap_or_fault_p (const_rtx mem
)
2331 if (MEM_READONLY_P (mem
))
2334 if (may_trap_or_fault_p (mem
))
2337 addr
= XEXP (mem
, 0);
2339 /* Call target hook to avoid the effects of -fpic etc.... */
2340 addr
= targetm
.delegitimize_address (addr
);
2343 switch (GET_CODE (addr
))
2351 addr
= XEXP (addr
, 0);
2355 addr
= XEXP (addr
, 1);
2358 if (CONST_INT_P (XEXP (addr
, 1)))
2359 addr
= XEXP (addr
, 0);
2366 if (SYMBOL_REF_DECL (addr
)
2367 && decl_readonly_section (SYMBOL_REF_DECL (addr
), 0))
2377 /* Return whether we can use store speculation for MEM. TOP_BB is the
2378 basic block above the conditional block where we are considering
2379 doing the speculative store. We look for whether MEM is set
2380 unconditionally later in the function. */
2383 noce_can_store_speculate_p (basic_block top_bb
, const_rtx mem
)
2385 basic_block dominator
;
2387 for (dominator
= get_immediate_dominator (CDI_POST_DOMINATORS
, top_bb
);
2389 dominator
= get_immediate_dominator (CDI_POST_DOMINATORS
, dominator
))
2393 FOR_BB_INSNS (dominator
, insn
)
2395 /* If we see something that might be a memory barrier, we
2396 have to stop looking. Even if the MEM is set later in
2397 the function, we still don't want to set it
2398 unconditionally before the barrier. */
2400 && (volatile_insn_p (PATTERN (insn
))
2401 || (CALL_P (insn
) && (!RTL_CONST_CALL_P (insn
)))))
2404 if (memory_modified_in_insn_p (mem
, insn
))
2406 if (modified_in_p (XEXP (mem
, 0), insn
))
2415 /* Given a simple IF-THEN-JOIN or IF-THEN-ELSE-JOIN block, attempt to convert
2416 it without using conditional execution. Return TRUE if we were successful
2417 at converting the block. */
2420 noce_process_if_block (struct noce_if_info
*if_info
)
2422 basic_block test_bb
= if_info
->test_bb
; /* test block */
2423 basic_block then_bb
= if_info
->then_bb
; /* THEN */
2424 basic_block else_bb
= if_info
->else_bb
; /* ELSE or NULL */
2425 basic_block join_bb
= if_info
->join_bb
; /* JOIN */
2426 rtx jump
= if_info
->jump
;
2427 rtx cond
= if_info
->cond
;
2430 rtx orig_x
, x
, a
, b
;
2432 /* We're looking for patterns of the form
2434 (1) if (...) x = a; else x = b;
2435 (2) x = b; if (...) x = a;
2436 (3) if (...) x = a; // as if with an initial x = x.
2438 The later patterns require jumps to be more expensive.
2440 ??? For future expansion, look for multiple X in such patterns. */
2442 /* Look for one of the potential sets. */
2443 insn_a
= first_active_insn (then_bb
);
2445 || insn_a
!= last_active_insn (then_bb
, FALSE
)
2446 || (set_a
= single_set (insn_a
)) == NULL_RTX
)
2449 x
= SET_DEST (set_a
);
2450 a
= SET_SRC (set_a
);
2452 /* Look for the other potential set. Make sure we've got equivalent
2454 /* ??? This is overconservative. Storing to two different mems is
2455 as easy as conditionally computing the address. Storing to a
2456 single mem merely requires a scratch memory to use as one of the
2457 destination addresses; often the memory immediately below the
2458 stack pointer is available for this. */
2462 insn_b
= first_active_insn (else_bb
);
2464 || insn_b
!= last_active_insn (else_bb
, FALSE
)
2465 || (set_b
= single_set (insn_b
)) == NULL_RTX
2466 || ! rtx_equal_p (x
, SET_DEST (set_b
)))
2471 insn_b
= prev_nonnote_nondebug_insn (if_info
->cond_earliest
);
2472 /* We're going to be moving the evaluation of B down from above
2473 COND_EARLIEST to JUMP. Make sure the relevant data is still
2476 || BLOCK_FOR_INSN (insn_b
) != BLOCK_FOR_INSN (if_info
->cond_earliest
)
2477 || !NONJUMP_INSN_P (insn_b
)
2478 || (set_b
= single_set (insn_b
)) == NULL_RTX
2479 || ! rtx_equal_p (x
, SET_DEST (set_b
))
2480 || ! noce_operand_ok (SET_SRC (set_b
))
2481 || reg_overlap_mentioned_p (x
, SET_SRC (set_b
))
2482 || modified_between_p (SET_SRC (set_b
), insn_b
, jump
)
2483 /* Likewise with X. In particular this can happen when
2484 noce_get_condition looks farther back in the instruction
2485 stream than one might expect. */
2486 || reg_overlap_mentioned_p (x
, cond
)
2487 || reg_overlap_mentioned_p (x
, a
)
2488 || modified_between_p (x
, insn_b
, jump
))
2489 insn_b
= set_b
= NULL_RTX
;
2492 /* If x has side effects then only the if-then-else form is safe to
2493 convert. But even in that case we would need to restore any notes
2494 (such as REG_INC) at then end. That can be tricky if
2495 noce_emit_move_insn expands to more than one insn, so disable the
2496 optimization entirely for now if there are side effects. */
2497 if (side_effects_p (x
))
2500 b
= (set_b
? SET_SRC (set_b
) : x
);
2502 /* Only operate on register destinations, and even then avoid extending
2503 the lifetime of hard registers on small register class machines. */
2506 || (HARD_REGISTER_P (x
)
2507 && targetm
.small_register_classes_for_mode_p (GET_MODE (x
))))
2509 if (GET_MODE (x
) == BLKmode
)
2512 if (GET_CODE (x
) == ZERO_EXTRACT
2513 && (!CONST_INT_P (XEXP (x
, 1))
2514 || !CONST_INT_P (XEXP (x
, 2))))
2517 x
= gen_reg_rtx (GET_MODE (GET_CODE (x
) == STRICT_LOW_PART
2518 ? XEXP (x
, 0) : x
));
2521 /* Don't operate on sources that may trap or are volatile. */
2522 if (! noce_operand_ok (a
) || ! noce_operand_ok (b
))
2526 /* Set up the info block for our subroutines. */
2527 if_info
->insn_a
= insn_a
;
2528 if_info
->insn_b
= insn_b
;
2533 /* Try optimizations in some approximation of a useful order. */
2534 /* ??? Should first look to see if X is live incoming at all. If it
2535 isn't, we don't need anything but an unconditional set. */
2537 /* Look and see if A and B are really the same. Avoid creating silly
2538 cmove constructs that no one will fix up later. */
2539 if (rtx_equal_p (a
, b
))
2541 /* If we have an INSN_B, we don't have to create any new rtl. Just
2542 move the instruction that we already have. If we don't have an
2543 INSN_B, that means that A == X, and we've got a noop move. In
2544 that case don't do anything and let the code below delete INSN_A. */
2545 if (insn_b
&& else_bb
)
2549 if (else_bb
&& insn_b
== BB_END (else_bb
))
2550 BB_END (else_bb
) = PREV_INSN (insn_b
);
2551 reorder_insns (insn_b
, insn_b
, PREV_INSN (jump
));
2553 /* If there was a REG_EQUAL note, delete it since it may have been
2554 true due to this insn being after a jump. */
2555 if ((note
= find_reg_note (insn_b
, REG_EQUAL
, NULL_RTX
)) != 0)
2556 remove_note (insn_b
, note
);
2560 /* If we have "x = b; if (...) x = a;", and x has side-effects, then
2561 x must be executed twice. */
2562 else if (insn_b
&& side_effects_p (orig_x
))
2569 if (!set_b
&& MEM_P (orig_x
))
2571 /* Disallow the "if (...) x = a;" form (implicit "else x = x;")
2572 for optimizations if writing to x may trap or fault,
2573 i.e. it's a memory other than a static var or a stack slot,
2574 is misaligned on strict aligned machines or is read-only. If
2575 x is a read-only memory, then the program is valid only if we
2576 avoid the store into it. If there are stores on both the
2577 THEN and ELSE arms, then we can go ahead with the conversion;
2578 either the program is broken, or the condition is always
2579 false such that the other memory is selected. */
2580 if (noce_mem_write_may_trap_or_fault_p (orig_x
))
2583 /* Avoid store speculation: given "if (...) x = a" where x is a
2584 MEM, we only want to do the store if x is always set
2585 somewhere in the function. This avoids cases like
2586 if (pthread_mutex_trylock(mutex))
2588 where we only want global_variable to be changed if the mutex
2589 is held. FIXME: This should ideally be expressed directly in
2591 if (!noce_can_store_speculate_p (test_bb
, orig_x
))
2595 if (noce_try_move (if_info
))
2597 if (noce_try_store_flag (if_info
))
2599 if (noce_try_bitop (if_info
))
2601 if (noce_try_minmax (if_info
))
2603 if (noce_try_abs (if_info
))
2605 if (HAVE_conditional_move
2606 && noce_try_cmove (if_info
))
2608 if (! targetm
.have_conditional_execution ())
2610 if (noce_try_store_flag_constants (if_info
))
2612 if (noce_try_addcc (if_info
))
2614 if (noce_try_store_flag_mask (if_info
))
2616 if (HAVE_conditional_move
2617 && noce_try_cmove_arith (if_info
))
2619 if (noce_try_sign_mask (if_info
))
2623 if (!else_bb
&& set_b
)
2625 insn_b
= set_b
= NULL_RTX
;
2634 /* If we used a temporary, fix it up now. */
2640 noce_emit_move_insn (orig_x
, x
);
2642 set_used_flags (orig_x
);
2643 unshare_all_rtl_in_chain (seq
);
2646 emit_insn_before_setloc (seq
, BB_END (test_bb
), INSN_LOCATOR (insn_a
));
2649 /* The original THEN and ELSE blocks may now be removed. The test block
2650 must now jump to the join block. If the test block and the join block
2651 can be merged, do so. */
2654 delete_basic_block (else_bb
);
2658 remove_edge (find_edge (test_bb
, join_bb
));
2660 remove_edge (find_edge (then_bb
, join_bb
));
2661 redirect_edge_and_branch_force (single_succ_edge (test_bb
), join_bb
);
2662 delete_basic_block (then_bb
);
2665 if (can_merge_blocks_p (test_bb
, join_bb
))
2667 merge_blocks (test_bb
, join_bb
);
2671 num_updated_if_blocks
++;
2675 /* Check whether a block is suitable for conditional move conversion.
2676 Every insn must be a simple set of a register to a constant or a
2677 register. For each assignment, store the value in the array VALS,
2678 indexed by register number, then store the register number in
2679 REGS. COND is the condition we will test. */
2682 check_cond_move_block (basic_block bb
, rtx
*vals
, VEC (int, heap
) **regs
,
2687 /* We can only handle simple jumps at the end of the basic block.
2688 It is almost impossible to update the CFG otherwise. */
2690 if (JUMP_P (insn
) && !onlyjump_p (insn
))
2693 FOR_BB_INSNS (bb
, insn
)
2697 if (!NONDEBUG_INSN_P (insn
) || JUMP_P (insn
))
2699 set
= single_set (insn
);
2703 dest
= SET_DEST (set
);
2704 src
= SET_SRC (set
);
2706 || (HARD_REGISTER_P (dest
)
2707 && targetm
.small_register_classes_for_mode_p (GET_MODE (dest
))))
2710 if (!CONSTANT_P (src
) && !register_operand (src
, VOIDmode
))
2713 if (side_effects_p (src
) || side_effects_p (dest
))
2716 if (may_trap_p (src
) || may_trap_p (dest
))
2719 /* Don't try to handle this if the source register was
2720 modified earlier in the block. */
2722 && vals
[REGNO (src
)] != NULL
)
2723 || (GET_CODE (src
) == SUBREG
&& REG_P (SUBREG_REG (src
))
2724 && vals
[REGNO (SUBREG_REG (src
))] != NULL
))
2727 /* Don't try to handle this if the destination register was
2728 modified earlier in the block. */
2729 if (vals
[REGNO (dest
)] != NULL
)
2732 /* Don't try to handle this if the condition uses the
2733 destination register. */
2734 if (reg_overlap_mentioned_p (dest
, cond
))
2737 /* Don't try to handle this if the source register is modified
2738 later in the block. */
2739 if (!CONSTANT_P (src
)
2740 && modified_between_p (src
, insn
, NEXT_INSN (BB_END (bb
))))
2743 vals
[REGNO (dest
)] = src
;
2745 VEC_safe_push (int, heap
, *regs
, REGNO (dest
));
2751 /* Given a basic block BB suitable for conditional move conversion,
2752 a condition COND, and arrays THEN_VALS and ELSE_VALS containing the
2753 register values depending on COND, emit the insns in the block as
2754 conditional moves. If ELSE_BLOCK is true, THEN_BB was already
2755 processed. The caller has started a sequence for the conversion.
2756 Return true if successful, false if something goes wrong. */
2759 cond_move_convert_if_block (struct noce_if_info
*if_infop
,
2760 basic_block bb
, rtx cond
,
2761 rtx
*then_vals
, rtx
*else_vals
,
2765 rtx insn
, cond_arg0
, cond_arg1
;
2767 code
= GET_CODE (cond
);
2768 cond_arg0
= XEXP (cond
, 0);
2769 cond_arg1
= XEXP (cond
, 1);
2771 FOR_BB_INSNS (bb
, insn
)
2773 rtx set
, target
, dest
, t
, e
;
2776 /* ??? Maybe emit conditional debug insn? */
2777 if (!NONDEBUG_INSN_P (insn
) || JUMP_P (insn
))
2779 set
= single_set (insn
);
2780 gcc_assert (set
&& REG_P (SET_DEST (set
)));
2782 dest
= SET_DEST (set
);
2783 regno
= REGNO (dest
);
2785 t
= then_vals
[regno
];
2786 e
= else_vals
[regno
];
2790 /* If this register was set in the then block, we already
2791 handled this case there. */
2804 target
= noce_emit_cmove (if_infop
, dest
, code
, cond_arg0
, cond_arg1
,
2810 noce_emit_move_insn (dest
, target
);
2816 /* Given a simple IF-THEN-JOIN or IF-THEN-ELSE-JOIN block, attempt to convert
2817 it using only conditional moves. Return TRUE if we were successful at
2818 converting the block. */
2821 cond_move_process_if_block (struct noce_if_info
*if_info
)
2823 basic_block test_bb
= if_info
->test_bb
;
2824 basic_block then_bb
= if_info
->then_bb
;
2825 basic_block else_bb
= if_info
->else_bb
;
2826 basic_block join_bb
= if_info
->join_bb
;
2827 rtx jump
= if_info
->jump
;
2828 rtx cond
= if_info
->cond
;
2830 int max_reg
, size
, c
, reg
;
2833 VEC (int, heap
) *then_regs
= NULL
;
2834 VEC (int, heap
) *else_regs
= NULL
;
2837 /* Build a mapping for each block to the value used for each
2839 max_reg
= max_reg_num ();
2840 size
= (max_reg
+ 1) * sizeof (rtx
);
2841 then_vals
= (rtx
*) alloca (size
);
2842 else_vals
= (rtx
*) alloca (size
);
2843 memset (then_vals
, 0, size
);
2844 memset (else_vals
, 0, size
);
2846 /* Make sure the blocks are suitable. */
2847 if (!check_cond_move_block (then_bb
, then_vals
, &then_regs
, cond
)
2849 && !check_cond_move_block (else_bb
, else_vals
, &else_regs
, cond
)))
2851 VEC_free (int, heap
, then_regs
);
2852 VEC_free (int, heap
, else_regs
);
2856 /* Make sure the blocks can be used together. If the same register
2857 is set in both blocks, and is not set to a constant in both
2858 cases, then both blocks must set it to the same register. We
2859 have already verified that if it is set to a register, that the
2860 source register does not change after the assignment. Also count
2861 the number of registers set in only one of the blocks. */
2863 FOR_EACH_VEC_ELT (int, then_regs
, i
, reg
)
2865 if (!then_vals
[reg
] && !else_vals
[reg
])
2868 if (!else_vals
[reg
])
2872 if (!CONSTANT_P (then_vals
[reg
])
2873 && !CONSTANT_P (else_vals
[reg
])
2874 && !rtx_equal_p (then_vals
[reg
], else_vals
[reg
]))
2876 VEC_free (int, heap
, then_regs
);
2877 VEC_free (int, heap
, else_regs
);
2883 /* Finish off c for MAX_CONDITIONAL_EXECUTE. */
2884 FOR_EACH_VEC_ELT (int, else_regs
, i
, reg
)
2885 if (!then_vals
[reg
])
2888 /* Make sure it is reasonable to convert this block. What matters
2889 is the number of assignments currently made in only one of the
2890 branches, since if we convert we are going to always execute
2892 if (c
> MAX_CONDITIONAL_EXECUTE
)
2894 VEC_free (int, heap
, then_regs
);
2895 VEC_free (int, heap
, else_regs
);
2899 /* Try to emit the conditional moves. First do the then block,
2900 then do anything left in the else blocks. */
2902 if (!cond_move_convert_if_block (if_info
, then_bb
, cond
,
2903 then_vals
, else_vals
, false)
2905 && !cond_move_convert_if_block (if_info
, else_bb
, cond
,
2906 then_vals
, else_vals
, true)))
2909 VEC_free (int, heap
, then_regs
);
2910 VEC_free (int, heap
, else_regs
);
2913 seq
= end_ifcvt_sequence (if_info
);
2916 VEC_free (int, heap
, then_regs
);
2917 VEC_free (int, heap
, else_regs
);
2921 loc_insn
= first_active_insn (then_bb
);
2924 loc_insn
= first_active_insn (else_bb
);
2925 gcc_assert (loc_insn
);
2927 emit_insn_before_setloc (seq
, jump
, INSN_LOCATOR (loc_insn
));
2931 delete_basic_block (else_bb
);
2935 remove_edge (find_edge (test_bb
, join_bb
));
2937 remove_edge (find_edge (then_bb
, join_bb
));
2938 redirect_edge_and_branch_force (single_succ_edge (test_bb
), join_bb
);
2939 delete_basic_block (then_bb
);
2942 if (can_merge_blocks_p (test_bb
, join_bb
))
2944 merge_blocks (test_bb
, join_bb
);
2948 num_updated_if_blocks
++;
2950 VEC_free (int, heap
, then_regs
);
2951 VEC_free (int, heap
, else_regs
);
2956 /* Determine if a given basic block heads a simple IF-THEN-JOIN or an
2957 IF-THEN-ELSE-JOIN block.
2959 If so, we'll try to convert the insns to not require the branch,
2960 using only transformations that do not require conditional execution.
2962 Return TRUE if we were successful at converting the block. */
2965 noce_find_if_block (basic_block test_bb
, edge then_edge
, edge else_edge
,
2968 basic_block then_bb
, else_bb
, join_bb
;
2969 bool then_else_reversed
= false;
2972 struct noce_if_info if_info
;
2974 /* We only ever should get here before reload. */
2975 gcc_assert (!reload_completed
);
2977 /* Recognize an IF-THEN-ELSE-JOIN block. */
2978 if (single_pred_p (then_edge
->dest
)
2979 && single_succ_p (then_edge
->dest
)
2980 && single_pred_p (else_edge
->dest
)
2981 && single_succ_p (else_edge
->dest
)
2982 && single_succ (then_edge
->dest
) == single_succ (else_edge
->dest
))
2984 then_bb
= then_edge
->dest
;
2985 else_bb
= else_edge
->dest
;
2986 join_bb
= single_succ (then_bb
);
2988 /* Recognize an IF-THEN-JOIN block. */
2989 else if (single_pred_p (then_edge
->dest
)
2990 && single_succ_p (then_edge
->dest
)
2991 && single_succ (then_edge
->dest
) == else_edge
->dest
)
2993 then_bb
= then_edge
->dest
;
2994 else_bb
= NULL_BLOCK
;
2995 join_bb
= else_edge
->dest
;
2997 /* Recognize an IF-ELSE-JOIN block. We can have those because the order
2998 of basic blocks in cfglayout mode does not matter, so the fallthrough
2999 edge can go to any basic block (and not just to bb->next_bb, like in
3001 else if (single_pred_p (else_edge
->dest
)
3002 && single_succ_p (else_edge
->dest
)
3003 && single_succ (else_edge
->dest
) == then_edge
->dest
)
3005 /* The noce transformations do not apply to IF-ELSE-JOIN blocks.
3006 To make this work, we have to invert the THEN and ELSE blocks
3007 and reverse the jump condition. */
3008 then_bb
= else_edge
->dest
;
3009 else_bb
= NULL_BLOCK
;
3010 join_bb
= single_succ (then_bb
);
3011 then_else_reversed
= true;
3014 /* Not a form we can handle. */
3017 /* The edges of the THEN and ELSE blocks cannot have complex edges. */
3018 if (single_succ_edge (then_bb
)->flags
& EDGE_COMPLEX
)
3021 && single_succ_edge (else_bb
)->flags
& EDGE_COMPLEX
)
3024 num_possible_if_blocks
++;
3029 "\nIF-THEN%s-JOIN block found, pass %d, test %d, then %d",
3030 (else_bb
) ? "-ELSE" : "",
3031 pass
, test_bb
->index
, then_bb
->index
);
3034 fprintf (dump_file
, ", else %d", else_bb
->index
);
3036 fprintf (dump_file
, ", join %d\n", join_bb
->index
);
3039 /* If the conditional jump is more than just a conditional
3040 jump, then we can not do if-conversion on this block. */
3041 jump
= BB_END (test_bb
);
3042 if (! onlyjump_p (jump
))
3045 /* If this is not a standard conditional jump, we can't parse it. */
3046 cond
= noce_get_condition (jump
, &cond_earliest
, then_else_reversed
);
3050 /* We must be comparing objects whose modes imply the size. */
3051 if (GET_MODE (XEXP (cond
, 0)) == BLKmode
)
3054 /* Initialize an IF_INFO struct to pass around. */
3055 memset (&if_info
, 0, sizeof if_info
);
3056 if_info
.test_bb
= test_bb
;
3057 if_info
.then_bb
= then_bb
;
3058 if_info
.else_bb
= else_bb
;
3059 if_info
.join_bb
= join_bb
;
3060 if_info
.cond
= cond
;
3061 if_info
.cond_earliest
= cond_earliest
;
3062 if_info
.jump
= jump
;
3063 if_info
.then_else_reversed
= then_else_reversed
;
3064 if_info
.branch_cost
= BRANCH_COST (optimize_bb_for_speed_p (test_bb
),
3065 predictable_edge_p (then_edge
));
3067 /* Do the real work. */
3069 if (noce_process_if_block (&if_info
))
3072 if (HAVE_conditional_move
3073 && cond_move_process_if_block (&if_info
))
3080 /* Merge the blocks and mark for local life update. */
3083 merge_if_block (struct ce_if_block
* ce_info
)
3085 basic_block test_bb
= ce_info
->test_bb
; /* last test block */
3086 basic_block then_bb
= ce_info
->then_bb
; /* THEN */
3087 basic_block else_bb
= ce_info
->else_bb
; /* ELSE or NULL */
3088 basic_block join_bb
= ce_info
->join_bb
; /* join block */
3089 basic_block combo_bb
;
3091 /* All block merging is done into the lower block numbers. */
3094 df_set_bb_dirty (test_bb
);
3096 /* Merge any basic blocks to handle && and || subtests. Each of
3097 the blocks are on the fallthru path from the predecessor block. */
3098 if (ce_info
->num_multiple_test_blocks
> 0)
3100 basic_block bb
= test_bb
;
3101 basic_block last_test_bb
= ce_info
->last_test_bb
;
3102 basic_block fallthru
= block_fallthru (bb
);
3107 fallthru
= block_fallthru (bb
);
3108 merge_blocks (combo_bb
, bb
);
3111 while (bb
!= last_test_bb
);
3114 /* Merge TEST block into THEN block. Normally the THEN block won't have a
3115 label, but it might if there were || tests. That label's count should be
3116 zero, and it normally should be removed. */
3120 merge_blocks (combo_bb
, then_bb
);
3124 /* The ELSE block, if it existed, had a label. That label count
3125 will almost always be zero, but odd things can happen when labels
3126 get their addresses taken. */
3129 merge_blocks (combo_bb
, else_bb
);
3133 /* If there was no join block reported, that means it was not adjacent
3134 to the others, and so we cannot merge them. */
3138 rtx last
= BB_END (combo_bb
);
3140 /* The outgoing edge for the current COMBO block should already
3141 be correct. Verify this. */
3142 if (EDGE_COUNT (combo_bb
->succs
) == 0)
3143 gcc_assert (find_reg_note (last
, REG_NORETURN
, NULL
)
3144 || (NONJUMP_INSN_P (last
)
3145 && GET_CODE (PATTERN (last
)) == TRAP_IF
3146 && (TRAP_CONDITION (PATTERN (last
))
3147 == const_true_rtx
)));
3150 /* There should still be something at the end of the THEN or ELSE
3151 blocks taking us to our final destination. */
3152 gcc_assert (JUMP_P (last
)
3153 || (EDGE_SUCC (combo_bb
, 0)->dest
== EXIT_BLOCK_PTR
3155 && SIBLING_CALL_P (last
))
3156 || ((EDGE_SUCC (combo_bb
, 0)->flags
& EDGE_EH
)
3157 && can_throw_internal (last
)));
3160 /* The JOIN block may have had quite a number of other predecessors too.
3161 Since we've already merged the TEST, THEN and ELSE blocks, we should
3162 have only one remaining edge from our if-then-else diamond. If there
3163 is more than one remaining edge, it must come from elsewhere. There
3164 may be zero incoming edges if the THEN block didn't actually join
3165 back up (as with a call to a non-return function). */
3166 else if (EDGE_COUNT (join_bb
->preds
) < 2
3167 && join_bb
!= EXIT_BLOCK_PTR
)
3169 /* We can merge the JOIN cleanly and update the dataflow try
3170 again on this pass.*/
3171 merge_blocks (combo_bb
, join_bb
);
3176 /* We cannot merge the JOIN. */
3178 /* The outgoing edge for the current COMBO block should already
3179 be correct. Verify this. */
3180 gcc_assert (single_succ_p (combo_bb
)
3181 && single_succ (combo_bb
) == join_bb
);
3183 /* Remove the jump and cruft from the end of the COMBO block. */
3184 if (join_bb
!= EXIT_BLOCK_PTR
)
3185 tidy_fallthru_edge (single_succ_edge (combo_bb
));
3188 num_updated_if_blocks
++;
3191 /* Find a block ending in a simple IF condition and try to transform it
3192 in some way. When converting a multi-block condition, put the new code
3193 in the first such block and delete the rest. Return a pointer to this
3194 first block if some transformation was done. Return NULL otherwise. */
3197 find_if_header (basic_block test_bb
, int pass
)
3199 ce_if_block_t ce_info
;
3203 /* The kind of block we're looking for has exactly two successors. */
3204 if (EDGE_COUNT (test_bb
->succs
) != 2)
3207 then_edge
= EDGE_SUCC (test_bb
, 0);
3208 else_edge
= EDGE_SUCC (test_bb
, 1);
3210 if (df_get_bb_dirty (then_edge
->dest
))
3212 if (df_get_bb_dirty (else_edge
->dest
))
3215 /* Neither edge should be abnormal. */
3216 if ((then_edge
->flags
& EDGE_COMPLEX
)
3217 || (else_edge
->flags
& EDGE_COMPLEX
))
3220 /* Nor exit the loop. */
3221 if ((then_edge
->flags
& EDGE_LOOP_EXIT
)
3222 || (else_edge
->flags
& EDGE_LOOP_EXIT
))
3225 /* The THEN edge is canonically the one that falls through. */
3226 if (then_edge
->flags
& EDGE_FALLTHRU
)
3228 else if (else_edge
->flags
& EDGE_FALLTHRU
)
3231 else_edge
= then_edge
;
3235 /* Otherwise this must be a multiway branch of some sort. */
3238 memset (&ce_info
, 0, sizeof (ce_info
));
3239 ce_info
.test_bb
= test_bb
;
3240 ce_info
.then_bb
= then_edge
->dest
;
3241 ce_info
.else_bb
= else_edge
->dest
;
3242 ce_info
.pass
= pass
;
3244 #ifdef IFCVT_INIT_EXTRA_FIELDS
3245 IFCVT_INIT_EXTRA_FIELDS (&ce_info
);
3248 if (!reload_completed
3249 && noce_find_if_block (test_bb
, then_edge
, else_edge
, pass
))
3252 if (reload_completed
3253 && targetm
.have_conditional_execution ()
3254 && cond_exec_find_if_block (&ce_info
))
3258 && optab_handler (ctrap_optab
, word_mode
) != CODE_FOR_nothing
3259 && find_cond_trap (test_bb
, then_edge
, else_edge
))
3262 if (dom_info_state (CDI_POST_DOMINATORS
) >= DOM_NO_FAST_QUERY
3263 && (reload_completed
|| !targetm
.have_conditional_execution ()))
3265 if (find_if_case_1 (test_bb
, then_edge
, else_edge
))
3267 if (find_if_case_2 (test_bb
, then_edge
, else_edge
))
3275 fprintf (dump_file
, "Conversion succeeded on pass %d.\n", pass
);
3276 /* Set this so we continue looking. */
3277 cond_exec_changed_p
= TRUE
;
3278 return ce_info
.test_bb
;
3281 /* Return true if a block has two edges, one of which falls through to the next
3282 block, and the other jumps to a specific block, so that we can tell if the
3283 block is part of an && test or an || test. Returns either -1 or the number
3284 of non-note, non-jump, non-USE/CLOBBER insns in the block. */
3287 block_jumps_and_fallthru_p (basic_block cur_bb
, basic_block target_bb
)
3290 int fallthru_p
= FALSE
;
3297 if (!cur_bb
|| !target_bb
)
3300 /* If no edges, obviously it doesn't jump or fallthru. */
3301 if (EDGE_COUNT (cur_bb
->succs
) == 0)
3304 FOR_EACH_EDGE (cur_edge
, ei
, cur_bb
->succs
)
3306 if (cur_edge
->flags
& EDGE_COMPLEX
)
3307 /* Anything complex isn't what we want. */
3310 else if (cur_edge
->flags
& EDGE_FALLTHRU
)
3313 else if (cur_edge
->dest
== target_bb
)
3320 if ((jump_p
& fallthru_p
) == 0)
3323 /* Don't allow calls in the block, since this is used to group && and ||
3324 together for conditional execution support. ??? we should support
3325 conditional execution support across calls for IA-64 some day, but
3326 for now it makes the code simpler. */
3327 end
= BB_END (cur_bb
);
3328 insn
= BB_HEAD (cur_bb
);
3330 while (insn
!= NULL_RTX
)
3337 && !DEBUG_INSN_P (insn
)
3338 && GET_CODE (PATTERN (insn
)) != USE
3339 && GET_CODE (PATTERN (insn
)) != CLOBBER
)
3345 insn
= NEXT_INSN (insn
);
3351 /* Determine if a given basic block heads a simple IF-THEN or IF-THEN-ELSE
3352 block. If so, we'll try to convert the insns to not require the branch.
3353 Return TRUE if we were successful at converting the block. */
3356 cond_exec_find_if_block (struct ce_if_block
* ce_info
)
3358 basic_block test_bb
= ce_info
->test_bb
;
3359 basic_block then_bb
= ce_info
->then_bb
;
3360 basic_block else_bb
= ce_info
->else_bb
;
3361 basic_block join_bb
= NULL_BLOCK
;
3366 ce_info
->last_test_bb
= test_bb
;
3368 /* We only ever should get here after reload,
3369 and if we have conditional execution. */
3370 gcc_assert (reload_completed
&& targetm
.have_conditional_execution ());
3372 /* Discover if any fall through predecessors of the current test basic block
3373 were && tests (which jump to the else block) or || tests (which jump to
3375 if (single_pred_p (test_bb
)
3376 && single_pred_edge (test_bb
)->flags
== EDGE_FALLTHRU
)
3378 basic_block bb
= single_pred (test_bb
);
3379 basic_block target_bb
;
3380 int max_insns
= MAX_CONDITIONAL_EXECUTE
;
3383 /* Determine if the preceding block is an && or || block. */
3384 if ((n_insns
= block_jumps_and_fallthru_p (bb
, else_bb
)) >= 0)
3386 ce_info
->and_and_p
= TRUE
;
3387 target_bb
= else_bb
;
3389 else if ((n_insns
= block_jumps_and_fallthru_p (bb
, then_bb
)) >= 0)
3391 ce_info
->and_and_p
= FALSE
;
3392 target_bb
= then_bb
;
3395 target_bb
= NULL_BLOCK
;
3397 if (target_bb
&& n_insns
<= max_insns
)
3399 int total_insns
= 0;
3402 ce_info
->last_test_bb
= test_bb
;
3404 /* Found at least one && or || block, look for more. */
3407 ce_info
->test_bb
= test_bb
= bb
;
3408 total_insns
+= n_insns
;
3411 if (!single_pred_p (bb
))
3414 bb
= single_pred (bb
);
3415 n_insns
= block_jumps_and_fallthru_p (bb
, target_bb
);
3417 while (n_insns
>= 0 && (total_insns
+ n_insns
) <= max_insns
);
3419 ce_info
->num_multiple_test_blocks
= blocks
;
3420 ce_info
->num_multiple_test_insns
= total_insns
;
3422 if (ce_info
->and_and_p
)
3423 ce_info
->num_and_and_blocks
= blocks
;
3425 ce_info
->num_or_or_blocks
= blocks
;
3429 /* The THEN block of an IF-THEN combo must have exactly one predecessor,
3430 other than any || blocks which jump to the THEN block. */
3431 if ((EDGE_COUNT (then_bb
->preds
) - ce_info
->num_or_or_blocks
) != 1)
3434 /* The edges of the THEN and ELSE blocks cannot have complex edges. */
3435 FOR_EACH_EDGE (cur_edge
, ei
, then_bb
->preds
)
3437 if (cur_edge
->flags
& EDGE_COMPLEX
)
3441 FOR_EACH_EDGE (cur_edge
, ei
, else_bb
->preds
)
3443 if (cur_edge
->flags
& EDGE_COMPLEX
)
3447 /* The THEN block of an IF-THEN combo must have zero or one successors. */
3448 if (EDGE_COUNT (then_bb
->succs
) > 0
3449 && (!single_succ_p (then_bb
)
3450 || (single_succ_edge (then_bb
)->flags
& EDGE_COMPLEX
)
3451 || (epilogue_completed
3452 && tablejump_p (BB_END (then_bb
), NULL
, NULL
))))
3455 /* If the THEN block has no successors, conditional execution can still
3456 make a conditional call. Don't do this unless the ELSE block has
3457 only one incoming edge -- the CFG manipulation is too ugly otherwise.
3458 Check for the last insn of the THEN block being an indirect jump, which
3459 is listed as not having any successors, but confuses the rest of the CE
3460 code processing. ??? we should fix this in the future. */
3461 if (EDGE_COUNT (then_bb
->succs
) == 0)
3463 if (single_pred_p (else_bb
))
3465 rtx last_insn
= BB_END (then_bb
);
3468 && NOTE_P (last_insn
)
3469 && last_insn
!= BB_HEAD (then_bb
))
3470 last_insn
= PREV_INSN (last_insn
);
3473 && JUMP_P (last_insn
)
3474 && ! simplejump_p (last_insn
))
3478 else_bb
= NULL_BLOCK
;
3484 /* If the THEN block's successor is the other edge out of the TEST block,
3485 then we have an IF-THEN combo without an ELSE. */
3486 else if (single_succ (then_bb
) == else_bb
)
3489 else_bb
= NULL_BLOCK
;
3492 /* If the THEN and ELSE block meet in a subsequent block, and the ELSE
3493 has exactly one predecessor and one successor, and the outgoing edge
3494 is not complex, then we have an IF-THEN-ELSE combo. */
3495 else if (single_succ_p (else_bb
)
3496 && single_succ (then_bb
) == single_succ (else_bb
)
3497 && single_pred_p (else_bb
)
3498 && !(single_succ_edge (else_bb
)->flags
& EDGE_COMPLEX
)
3499 && !(epilogue_completed
3500 && tablejump_p (BB_END (else_bb
), NULL
, NULL
)))
3501 join_bb
= single_succ (else_bb
);
3503 /* Otherwise it is not an IF-THEN or IF-THEN-ELSE combination. */
3507 num_possible_if_blocks
++;
3512 "\nIF-THEN%s block found, pass %d, start block %d "
3513 "[insn %d], then %d [%d]",
3514 (else_bb
) ? "-ELSE" : "",
3517 BB_HEAD (test_bb
) ? (int)INSN_UID (BB_HEAD (test_bb
)) : -1,
3519 BB_HEAD (then_bb
) ? (int)INSN_UID (BB_HEAD (then_bb
)) : -1);
3522 fprintf (dump_file
, ", else %d [%d]",
3524 BB_HEAD (else_bb
) ? (int)INSN_UID (BB_HEAD (else_bb
)) : -1);
3526 fprintf (dump_file
, ", join %d [%d]",
3528 BB_HEAD (join_bb
) ? (int)INSN_UID (BB_HEAD (join_bb
)) : -1);
3530 if (ce_info
->num_multiple_test_blocks
> 0)
3531 fprintf (dump_file
, ", %d %s block%s last test %d [%d]",
3532 ce_info
->num_multiple_test_blocks
,
3533 (ce_info
->and_and_p
) ? "&&" : "||",
3534 (ce_info
->num_multiple_test_blocks
== 1) ? "" : "s",
3535 ce_info
->last_test_bb
->index
,
3536 ((BB_HEAD (ce_info
->last_test_bb
))
3537 ? (int)INSN_UID (BB_HEAD (ce_info
->last_test_bb
))
3540 fputc ('\n', dump_file
);
3543 /* Make sure IF, THEN, and ELSE, blocks are adjacent. Actually, we get the
3544 first condition for free, since we've already asserted that there's a
3545 fallthru edge from IF to THEN. Likewise for the && and || blocks, since
3546 we checked the FALLTHRU flag, those are already adjacent to the last IF
3548 /* ??? As an enhancement, move the ELSE block. Have to deal with
3549 BLOCK notes, if by no other means than backing out the merge if they
3550 exist. Sticky enough I don't want to think about it now. */
3552 if (else_bb
&& (next
= next
->next_bb
) != else_bb
)
3554 if ((next
= next
->next_bb
) != join_bb
&& join_bb
!= EXIT_BLOCK_PTR
)
3562 /* Do the real work. */
3564 ce_info
->else_bb
= else_bb
;
3565 ce_info
->join_bb
= join_bb
;
3567 /* If we have && and || tests, try to first handle combining the && and ||
3568 tests into the conditional code, and if that fails, go back and handle
3569 it without the && and ||, which at present handles the && case if there
3570 was no ELSE block. */
3571 if (cond_exec_process_if_block (ce_info
, TRUE
))
3574 if (ce_info
->num_multiple_test_blocks
)
3578 if (cond_exec_process_if_block (ce_info
, FALSE
))
3585 /* Convert a branch over a trap, or a branch
3586 to a trap, into a conditional trap. */
3589 find_cond_trap (basic_block test_bb
, edge then_edge
, edge else_edge
)
3591 basic_block then_bb
= then_edge
->dest
;
3592 basic_block else_bb
= else_edge
->dest
;
3593 basic_block other_bb
, trap_bb
;
3594 rtx trap
, jump
, cond
, cond_earliest
, seq
;
3597 /* Locate the block with the trap instruction. */
3598 /* ??? While we look for no successors, we really ought to allow
3599 EH successors. Need to fix merge_if_block for that to work. */
3600 if ((trap
= block_has_only_trap (then_bb
)) != NULL
)
3601 trap_bb
= then_bb
, other_bb
= else_bb
;
3602 else if ((trap
= block_has_only_trap (else_bb
)) != NULL
)
3603 trap_bb
= else_bb
, other_bb
= then_bb
;
3609 fprintf (dump_file
, "\nTRAP-IF block found, start %d, trap %d\n",
3610 test_bb
->index
, trap_bb
->index
);
3613 /* If this is not a standard conditional jump, we can't parse it. */
3614 jump
= BB_END (test_bb
);
3615 cond
= noce_get_condition (jump
, &cond_earliest
, false);
3619 /* If the conditional jump is more than just a conditional jump, then
3620 we can not do if-conversion on this block. */
3621 if (! onlyjump_p (jump
))
3624 /* We must be comparing objects whose modes imply the size. */
3625 if (GET_MODE (XEXP (cond
, 0)) == BLKmode
)
3628 /* Reverse the comparison code, if necessary. */
3629 code
= GET_CODE (cond
);
3630 if (then_bb
== trap_bb
)
3632 code
= reversed_comparison_code (cond
, jump
);
3633 if (code
== UNKNOWN
)
3637 /* Attempt to generate the conditional trap. */
3638 seq
= gen_cond_trap (code
, copy_rtx (XEXP (cond
, 0)),
3639 copy_rtx (XEXP (cond
, 1)),
3640 TRAP_CODE (PATTERN (trap
)));
3644 /* Emit the new insns before cond_earliest. */
3645 emit_insn_before_setloc (seq
, cond_earliest
, INSN_LOCATOR (trap
));
3647 /* Delete the trap block if possible. */
3648 remove_edge (trap_bb
== then_bb
? then_edge
: else_edge
);
3649 df_set_bb_dirty (test_bb
);
3650 df_set_bb_dirty (then_bb
);
3651 df_set_bb_dirty (else_bb
);
3653 if (EDGE_COUNT (trap_bb
->preds
) == 0)
3655 delete_basic_block (trap_bb
);
3659 /* Wire together the blocks again. */
3660 if (current_ir_type () == IR_RTL_CFGLAYOUT
)
3661 single_succ_edge (test_bb
)->flags
|= EDGE_FALLTHRU
;
3666 lab
= JUMP_LABEL (jump
);
3667 newjump
= emit_jump_insn_after (gen_jump (lab
), jump
);
3668 LABEL_NUSES (lab
) += 1;
3669 JUMP_LABEL (newjump
) = lab
;
3670 emit_barrier_after (newjump
);
3674 if (can_merge_blocks_p (test_bb
, other_bb
))
3676 merge_blocks (test_bb
, other_bb
);
3680 num_updated_if_blocks
++;
3684 /* Subroutine of find_cond_trap: if BB contains only a trap insn,
3688 block_has_only_trap (basic_block bb
)
3692 /* We're not the exit block. */
3693 if (bb
== EXIT_BLOCK_PTR
)
3696 /* The block must have no successors. */
3697 if (EDGE_COUNT (bb
->succs
) > 0)
3700 /* The only instruction in the THEN block must be the trap. */
3701 trap
= first_active_insn (bb
);
3702 if (! (trap
== BB_END (bb
)
3703 && GET_CODE (PATTERN (trap
)) == TRAP_IF
3704 && TRAP_CONDITION (PATTERN (trap
)) == const_true_rtx
))
3710 /* Look for IF-THEN-ELSE cases in which one of THEN or ELSE is
3711 transformable, but not necessarily the other. There need be no
3714 Return TRUE if we were successful at converting the block.
3716 Cases we'd like to look at:
3719 if (test) goto over; // x not live
3727 if (! test) goto label;
3730 if (test) goto E; // x not live
3744 (3) // This one's really only interesting for targets that can do
3745 // multiway branching, e.g. IA-64 BBB bundles. For other targets
3746 // it results in multiple branches on a cache line, which often
3747 // does not sit well with predictors.
3749 if (test1) goto E; // predicted not taken
3765 (A) Don't do (2) if the branch is predicted against the block we're
3766 eliminating. Do it anyway if we can eliminate a branch; this requires
3767 that the sole successor of the eliminated block postdominate the other
3770 (B) With CE, on (3) we can steal from both sides of the if, creating
3779 Again, this is most useful if J postdominates.
3781 (C) CE substitutes for helpful life information.
3783 (D) These heuristics need a lot of work. */
3785 /* Tests for case 1 above. */
3788 find_if_case_1 (basic_block test_bb
, edge then_edge
, edge else_edge
)
3790 basic_block then_bb
= then_edge
->dest
;
3791 basic_block else_bb
= else_edge
->dest
;
3795 /* If we are partitioning hot/cold basic blocks, we don't want to
3796 mess up unconditional or indirect jumps that cross between hot
3799 Basic block partitioning may result in some jumps that appear to
3800 be optimizable (or blocks that appear to be mergeable), but which really
3801 must be left untouched (they are required to make it safely across
3802 partition boundaries). See the comments at the top of
3803 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
3805 if ((BB_END (then_bb
)
3806 && find_reg_note (BB_END (then_bb
), REG_CROSSING_JUMP
, NULL_RTX
))
3807 || (BB_END (test_bb
)
3808 && find_reg_note (BB_END (test_bb
), REG_CROSSING_JUMP
, NULL_RTX
))
3809 || (BB_END (else_bb
)
3810 && find_reg_note (BB_END (else_bb
), REG_CROSSING_JUMP
,
3814 /* THEN has one successor. */
3815 if (!single_succ_p (then_bb
))
3818 /* THEN does not fall through, but is not strange either. */
3819 if (single_succ_edge (then_bb
)->flags
& (EDGE_COMPLEX
| EDGE_FALLTHRU
))
3822 /* THEN has one predecessor. */
3823 if (!single_pred_p (then_bb
))
3826 /* THEN must do something. */
3827 if (forwarder_block_p (then_bb
))
3830 num_possible_if_blocks
++;
3833 "\nIF-CASE-1 found, start %d, then %d\n",
3834 test_bb
->index
, then_bb
->index
);
3836 /* THEN is small. */
3837 if (! cheap_bb_rtx_cost_p (then_bb
,
3838 COSTS_N_INSNS (BRANCH_COST (optimize_bb_for_speed_p (then_edge
->src
),
3839 predictable_edge_p (then_edge
)))))
3842 /* Registers set are dead, or are predicable. */
3843 if (! dead_or_predicable (test_bb
, then_bb
, else_bb
,
3844 single_succ (then_bb
), 1))
3847 /* Conversion went ok, including moving the insns and fixing up the
3848 jump. Adjust the CFG to match. */
3850 /* We can avoid creating a new basic block if then_bb is immediately
3851 followed by else_bb, i.e. deleting then_bb allows test_bb to fall
3854 if (then_bb
->next_bb
== else_bb
3855 && then_bb
->prev_bb
== test_bb
3856 && else_bb
!= EXIT_BLOCK_PTR
)
3858 redirect_edge_succ (FALLTHRU_EDGE (test_bb
), else_bb
);
3862 new_bb
= redirect_edge_and_branch_force (FALLTHRU_EDGE (test_bb
),
3865 df_set_bb_dirty (test_bb
);
3866 df_set_bb_dirty (else_bb
);
3868 then_bb_index
= then_bb
->index
;
3869 delete_basic_block (then_bb
);
3871 /* Make rest of code believe that the newly created block is the THEN_BB
3872 block we removed. */
3875 df_bb_replace (then_bb_index
, new_bb
);
3876 /* Since the fallthru edge was redirected from test_bb to new_bb,
3877 we need to ensure that new_bb is in the same partition as
3878 test bb (you can not fall through across section boundaries). */
3879 BB_COPY_PARTITION (new_bb
, test_bb
);
3883 num_updated_if_blocks
++;
3888 /* Test for case 2 above. */
3891 find_if_case_2 (basic_block test_bb
, edge then_edge
, edge else_edge
)
3893 basic_block then_bb
= then_edge
->dest
;
3894 basic_block else_bb
= else_edge
->dest
;
3898 /* If we are partitioning hot/cold basic blocks, we don't want to
3899 mess up unconditional or indirect jumps that cross between hot
3902 Basic block partitioning may result in some jumps that appear to
3903 be optimizable (or blocks that appear to be mergeable), but which really
3904 must be left untouched (they are required to make it safely across
3905 partition boundaries). See the comments at the top of
3906 bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
3908 if ((BB_END (then_bb
)
3909 && find_reg_note (BB_END (then_bb
), REG_CROSSING_JUMP
, NULL_RTX
))
3910 || (BB_END (test_bb
)
3911 && find_reg_note (BB_END (test_bb
), REG_CROSSING_JUMP
, NULL_RTX
))
3912 || (BB_END (else_bb
)
3913 && find_reg_note (BB_END (else_bb
), REG_CROSSING_JUMP
,
3917 /* ELSE has one successor. */
3918 if (!single_succ_p (else_bb
))
3921 else_succ
= single_succ_edge (else_bb
);
3923 /* ELSE outgoing edge is not complex. */
3924 if (else_succ
->flags
& EDGE_COMPLEX
)
3927 /* ELSE has one predecessor. */
3928 if (!single_pred_p (else_bb
))
3931 /* THEN is not EXIT. */
3932 if (then_bb
->index
< NUM_FIXED_BLOCKS
)
3935 /* ELSE is predicted or SUCC(ELSE) postdominates THEN. */
3936 note
= find_reg_note (BB_END (test_bb
), REG_BR_PROB
, NULL_RTX
);
3937 if (note
&& INTVAL (XEXP (note
, 0)) >= REG_BR_PROB_BASE
/ 2)
3939 else if (else_succ
->dest
->index
< NUM_FIXED_BLOCKS
3940 || dominated_by_p (CDI_POST_DOMINATORS
, then_bb
,
3946 num_possible_if_blocks
++;
3949 "\nIF-CASE-2 found, start %d, else %d\n",
3950 test_bb
->index
, else_bb
->index
);
3952 /* ELSE is small. */
3953 if (! cheap_bb_rtx_cost_p (else_bb
,
3954 COSTS_N_INSNS (BRANCH_COST (optimize_bb_for_speed_p (else_edge
->src
),
3955 predictable_edge_p (else_edge
)))))
3958 /* Registers set are dead, or are predicable. */
3959 if (! dead_or_predicable (test_bb
, else_bb
, then_bb
, else_succ
->dest
, 0))
3962 /* Conversion went ok, including moving the insns and fixing up the
3963 jump. Adjust the CFG to match. */
3965 df_set_bb_dirty (test_bb
);
3966 df_set_bb_dirty (then_bb
);
3967 delete_basic_block (else_bb
);
3970 num_updated_if_blocks
++;
3972 /* ??? We may now fallthru from one of THEN's successors into a join
3973 block. Rerun cleanup_cfg? Examine things manually? Wait? */
3978 /* Used by the code above to perform the actual rtl transformations.
3979 Return TRUE if successful.
3981 TEST_BB is the block containing the conditional branch. MERGE_BB
3982 is the block containing the code to manipulate. NEW_DEST is the
3983 label TEST_BB should be branching to after the conversion.
3984 REVERSEP is true if the sense of the branch should be reversed. */
3987 dead_or_predicable (basic_block test_bb
, basic_block merge_bb
,
3988 basic_block other_bb
, basic_block new_dest
, int reversep
)
3990 rtx head
, end
, jump
, earliest
= NULL_RTX
, old_dest
, new_label
= NULL_RTX
;
3991 /* Number of pending changes. */
3992 int n_validated_changes
= 0;
3994 jump
= BB_END (test_bb
);
3996 /* Find the extent of the real code in the merge block. */
3997 head
= BB_HEAD (merge_bb
);
3998 end
= BB_END (merge_bb
);
4000 while (DEBUG_INSN_P (end
) && end
!= head
)
4001 end
= PREV_INSN (end
);
4003 /* If merge_bb ends with a tablejump, predicating/moving insn's
4004 into test_bb and then deleting merge_bb will result in the jumptable
4005 that follows merge_bb being removed along with merge_bb and then we
4006 get an unresolved reference to the jumptable. */
4007 if (tablejump_p (end
, NULL
, NULL
))
4011 head
= NEXT_INSN (head
);
4012 while (DEBUG_INSN_P (head
) && head
!= end
)
4013 head
= NEXT_INSN (head
);
4018 head
= end
= NULL_RTX
;
4021 head
= NEXT_INSN (head
);
4022 while (DEBUG_INSN_P (head
) && head
!= end
)
4023 head
= NEXT_INSN (head
);
4030 head
= end
= NULL_RTX
;
4033 end
= PREV_INSN (end
);
4034 while (DEBUG_INSN_P (end
) && end
!= head
)
4035 end
= PREV_INSN (end
);
4038 /* Disable handling dead code by conditional execution if the machine needs
4039 to do anything funny with the tests, etc. */
4040 #ifndef IFCVT_MODIFY_TESTS
4041 if (targetm
.have_conditional_execution ())
4043 /* In the conditional execution case, we have things easy. We know
4044 the condition is reversible. We don't have to check life info
4045 because we're going to conditionally execute the code anyway.
4046 All that's left is making sure the insns involved can actually
4051 cond
= cond_exec_get_condition (jump
);
4055 prob_val
= find_reg_note (jump
, REG_BR_PROB
, NULL_RTX
);
4057 prob_val
= XEXP (prob_val
, 0);
4061 enum rtx_code rev
= reversed_comparison_code (cond
, jump
);
4064 cond
= gen_rtx_fmt_ee (rev
, GET_MODE (cond
), XEXP (cond
, 0),
4067 prob_val
= GEN_INT (REG_BR_PROB_BASE
- INTVAL (prob_val
));
4070 if (cond_exec_process_insns (NULL
, head
, end
, cond
, prob_val
, 0)
4071 && verify_changes (0))
4072 n_validated_changes
= num_validated_changes ();
4079 /* If we allocated new pseudos (e.g. in the conditional move
4080 expander called from noce_emit_cmove), we must resize the
4082 if (max_regno
< max_reg_num ())
4083 max_regno
= max_reg_num ();
4085 /* Try the NCE path if the CE path did not result in any changes. */
4086 if (n_validated_changes
== 0)
4092 /* In the non-conditional execution case, we have to verify that there
4093 are no trapping operations, no calls, no references to memory, and
4094 that any registers modified are dead at the branch site. */
4096 if (!any_condjump_p (jump
))
4099 /* Find the extent of the conditional. */
4100 cond
= noce_get_condition (jump
, &earliest
, false);
4104 live
= BITMAP_ALLOC (®_obstack
);
4105 simulate_backwards_to_point (merge_bb
, live
, end
);
4106 success
= can_move_insns_across (head
, end
, earliest
, jump
,
4108 df_get_live_in (other_bb
), NULL
);
4115 /* We don't want to use normal invert_jump or redirect_jump because
4116 we don't want to delete_insn called. Also, we want to do our own
4117 change group management. */
4119 old_dest
= JUMP_LABEL (jump
);
4120 if (other_bb
!= new_dest
)
4122 new_label
= block_label (new_dest
);
4124 ? ! invert_jump_1 (jump
, new_label
)
4125 : ! redirect_jump_1 (jump
, new_label
))
4129 if (verify_changes (n_validated_changes
))
4130 confirm_change_group ();
4134 if (other_bb
!= new_dest
)
4136 redirect_jump_2 (jump
, old_dest
, new_label
, 0, reversep
);
4138 redirect_edge_succ (BRANCH_EDGE (test_bb
), new_dest
);
4141 gcov_type count
, probability
;
4142 count
= BRANCH_EDGE (test_bb
)->count
;
4143 BRANCH_EDGE (test_bb
)->count
= FALLTHRU_EDGE (test_bb
)->count
;
4144 FALLTHRU_EDGE (test_bb
)->count
= count
;
4145 probability
= BRANCH_EDGE (test_bb
)->probability
;
4146 BRANCH_EDGE (test_bb
)->probability
4147 = FALLTHRU_EDGE (test_bb
)->probability
;
4148 FALLTHRU_EDGE (test_bb
)->probability
= probability
;
4149 update_br_prob_note (test_bb
);
4153 /* Move the insns out of MERGE_BB to before the branch. */
4158 if (end
== BB_END (merge_bb
))
4159 BB_END (merge_bb
) = PREV_INSN (head
);
4161 /* PR 21767: When moving insns above a conditional branch, REG_EQUAL
4162 notes might become invalid. */
4168 if (! INSN_P (insn
))
4170 note
= find_reg_note (insn
, REG_EQUAL
, NULL_RTX
);
4173 set
= single_set (insn
);
4174 if (!set
|| !function_invariant_p (SET_SRC (set
))
4175 || !function_invariant_p (XEXP (note
, 0)))
4176 remove_note (insn
, note
);
4177 } while (insn
!= end
&& (insn
= NEXT_INSN (insn
)));
4179 reorder_insns (head
, end
, PREV_INSN (earliest
));
4182 /* Remove the jump and edge if we can. */
4183 if (other_bb
== new_dest
)
4186 remove_edge (BRANCH_EDGE (test_bb
));
4187 /* ??? Can't merge blocks here, as then_bb is still in use.
4188 At minimum, the merge will get done just before bb-reorder. */
4198 /* Main entry point for all if-conversion. */
4208 df_live_add_problem ();
4209 df_live_set_all_dirty ();
4212 num_possible_if_blocks
= 0;
4213 num_updated_if_blocks
= 0;
4214 num_true_changes
= 0;
4216 loop_optimizer_init (AVOID_CFG_MODIFICATIONS
);
4217 mark_loop_exit_edges ();
4218 loop_optimizer_finalize ();
4219 free_dominance_info (CDI_DOMINATORS
);
4221 /* Compute postdominators. */
4222 calculate_dominance_info (CDI_POST_DOMINATORS
);
4224 df_set_flags (DF_LR_RUN_DCE
);
4226 /* Go through each of the basic blocks looking for things to convert. If we
4227 have conditional execution, we make multiple passes to allow us to handle
4228 IF-THEN{-ELSE} blocks within other IF-THEN{-ELSE} blocks. */
4233 /* Only need to do dce on the first pass. */
4234 df_clear_flags (DF_LR_RUN_DCE
);
4235 cond_exec_changed_p
= FALSE
;
4238 #ifdef IFCVT_MULTIPLE_DUMPS
4239 if (dump_file
&& pass
> 1)
4240 fprintf (dump_file
, "\n\n========== Pass %d ==========\n", pass
);
4246 while (!df_get_bb_dirty (bb
)
4247 && (new_bb
= find_if_header (bb
, pass
)) != NULL
)
4251 #ifdef IFCVT_MULTIPLE_DUMPS
4252 if (dump_file
&& cond_exec_changed_p
)
4254 if (dump_flags
& TDF_SLIM
)
4255 print_rtl_slim_with_bb (dump_file
, get_insns (), dump_flags
);
4257 print_rtl_with_bb (dump_file
, get_insns ());
4261 while (cond_exec_changed_p
);
4263 #ifdef IFCVT_MULTIPLE_DUMPS
4265 fprintf (dump_file
, "\n\n========== no more changes\n");
4268 free_dominance_info (CDI_POST_DOMINATORS
);
4273 clear_aux_for_blocks ();
4275 /* If we allocated new pseudos, we must resize the array for sched1. */
4276 if (max_regno
< max_reg_num ())
4277 max_regno
= max_reg_num ();
4279 /* Write the final stats. */
4280 if (dump_file
&& num_possible_if_blocks
> 0)
4283 "\n%d possible IF blocks searched.\n",
4284 num_possible_if_blocks
);
4286 "%d IF blocks converted.\n",
4287 num_updated_if_blocks
);
4289 "%d true changes made.\n\n\n",
4294 df_remove_problem (df_live
);
4296 #ifdef ENABLE_CHECKING
4297 verify_flow_info ();
4302 gate_handle_if_conversion (void)
4304 return (optimize
> 0)
4305 && dbg_cnt (if_conversion
);
4308 /* If-conversion and CFG cleanup. */
4310 rest_of_handle_if_conversion (void)
4312 if (flag_if_conversion
)
4315 dump_flow_info (dump_file
, dump_flags
);
4316 cleanup_cfg (CLEANUP_EXPENSIVE
);
4324 struct rtl_opt_pass pass_rtl_ifcvt
=
4329 gate_handle_if_conversion
, /* gate */
4330 rest_of_handle_if_conversion
, /* execute */
4333 0, /* static_pass_number */
4334 TV_IFCVT
, /* tv_id */
4335 0, /* properties_required */
4336 0, /* properties_provided */
4337 0, /* properties_destroyed */
4338 0, /* todo_flags_start */
4339 TODO_df_finish
| TODO_verify_rtl_sharing
|
4340 TODO_dump_func
/* todo_flags_finish */
4345 gate_handle_if_after_combine (void)
4347 return optimize
> 0 && flag_if_conversion
4348 && dbg_cnt (if_after_combine
);
4352 /* Rerun if-conversion, as combine may have simplified things enough
4353 to now meet sequence length restrictions. */
4355 rest_of_handle_if_after_combine (void)
4361 struct rtl_opt_pass pass_if_after_combine
=
4366 gate_handle_if_after_combine
, /* gate */
4367 rest_of_handle_if_after_combine
, /* execute */
4370 0, /* static_pass_number */
4371 TV_IFCVT
, /* tv_id */
4372 0, /* properties_required */
4373 0, /* properties_provided */
4374 0, /* properties_destroyed */
4375 0, /* todo_flags_start */
4376 TODO_df_finish
| TODO_verify_rtl_sharing
|
4378 TODO_ggc_collect
/* todo_flags_finish */
4384 gate_handle_if_after_reload (void)
4386 return optimize
> 0 && flag_if_conversion2
4387 && dbg_cnt (if_after_reload
);
4391 rest_of_handle_if_after_reload (void)
4398 struct rtl_opt_pass pass_if_after_reload
=
4403 gate_handle_if_after_reload
, /* gate */
4404 rest_of_handle_if_after_reload
, /* execute */
4407 0, /* static_pass_number */
4408 TV_IFCVT2
, /* tv_id */
4409 0, /* properties_required */
4410 0, /* properties_provided */
4411 0, /* properties_destroyed */
4412 0, /* todo_flags_start */
4413 TODO_df_finish
| TODO_verify_rtl_sharing
|
4415 TODO_ggc_collect
/* todo_flags_finish */