1 /* If-conversion support.
2 Copyright (C) 2000, 2001 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it
7 under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
11 GCC is distributed in the hope that it will be useful, but WITHOUT
12 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
13 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
14 License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING. If not, write to the Free
18 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
28 #include "insn-config.h"
30 #include "hard-reg-set.h"
31 #include "basic-block.h"
39 #ifndef HAVE_conditional_execution
40 #define HAVE_conditional_execution 0
42 #ifndef HAVE_conditional_move
43 #define HAVE_conditional_move 0
54 #ifndef HAVE_conditional_trap
55 #define HAVE_conditional_trap 0
58 #ifndef MAX_CONDITIONAL_EXECUTE
59 #define MAX_CONDITIONAL_EXECUTE (BRANCH_COST + 1)
62 #define NULL_EDGE ((struct edge_def *)NULL)
63 #define NULL_BLOCK ((struct basic_block_def *)NULL)
65 /* # of IF-THEN or IF-THEN-ELSE blocks we looked at */
66 static int num_possible_if_blocks
;
68 /* # of IF-THEN or IF-THEN-ELSE blocks were converted to conditional
70 static int num_updated_if_blocks
;
72 /* # of basic blocks that were removed. */
73 static int num_removed_blocks
;
75 /* True if life data ok at present. */
76 static bool life_data_ok
;
78 /* The post-dominator relation on the original block numbers. */
79 static sbitmap
*post_dominators
;
81 /* Forward references. */
82 static int count_bb_insns
PARAMS ((basic_block
));
83 static rtx first_active_insn
PARAMS ((basic_block
));
84 static int last_active_insn_p
PARAMS ((basic_block
, rtx
));
85 static int seq_contains_jump
PARAMS ((rtx
));
87 static int cond_exec_process_insns
PARAMS ((rtx
, rtx
, rtx
, rtx
, int));
88 static rtx cond_exec_get_condition
PARAMS ((rtx
));
89 static int cond_exec_process_if_block
PARAMS ((basic_block
, basic_block
,
90 basic_block
, basic_block
));
92 static rtx noce_get_condition
PARAMS ((rtx
, rtx
*));
93 static int noce_operand_ok
PARAMS ((rtx
));
94 static int noce_process_if_block
PARAMS ((basic_block
, basic_block
,
95 basic_block
, basic_block
));
97 static int process_if_block
PARAMS ((basic_block
, basic_block
,
98 basic_block
, basic_block
));
99 static void merge_if_block
PARAMS ((basic_block
, basic_block
,
100 basic_block
, basic_block
));
102 static int find_if_header
PARAMS ((basic_block
));
103 static int find_if_block
PARAMS ((basic_block
, edge
, edge
));
104 static int find_if_case_1
PARAMS ((basic_block
, edge
, edge
));
105 static int find_if_case_2
PARAMS ((basic_block
, edge
, edge
));
106 static int find_cond_trap
PARAMS ((basic_block
, edge
, edge
));
107 static int find_memory
PARAMS ((rtx
*, void *));
108 static int dead_or_predicable
PARAMS ((basic_block
, basic_block
,
109 basic_block
, basic_block
, int));
110 static void noce_emit_move_insn
PARAMS ((rtx
, rtx
));
112 /* Abuse the basic_block AUX field to store the original block index,
113 as well as a flag indicating that the block should be rescaned for
116 #define SET_ORIG_INDEX(BB,I) ((BB)->aux = (void *)((size_t)(I) << 1))
117 #define ORIG_INDEX(BB) ((size_t)(BB)->aux >> 1)
118 #define SET_UPDATE_LIFE(BB) ((BB)->aux = (void *)((size_t)(BB)->aux | 1))
119 #define UPDATE_LIFE(BB) ((size_t)(BB)->aux & 1)
122 /* Count the number of non-jump active insns in BB. */
133 if (GET_CODE (insn
) == CALL_INSN
|| GET_CODE (insn
) == INSN
)
138 insn
= NEXT_INSN (insn
);
144 /* Return the first non-jump active insn in the basic block. */
147 first_active_insn (bb
)
152 if (GET_CODE (insn
) == CODE_LABEL
)
156 insn
= NEXT_INSN (insn
);
159 while (GET_CODE (insn
) == NOTE
)
163 insn
= NEXT_INSN (insn
);
166 if (GET_CODE (insn
) == JUMP_INSN
)
172 /* Return true if INSN is the last active non-jump insn in BB. */
175 last_active_insn_p (bb
, insn
)
183 insn
= NEXT_INSN (insn
);
185 while (GET_CODE (insn
) == NOTE
);
187 return GET_CODE (insn
) == JUMP_INSN
;
190 /* It is possible, especially when having dealt with multi-word
191 arithmetic, for the expanders to have emitted jumps. Search
192 through the sequence and return TRUE if a jump exists so that
193 we can abort the conversion. */
196 seq_contains_jump (insn
)
201 if (GET_CODE (insn
) == JUMP_INSN
)
203 insn
= NEXT_INSN (insn
);
208 /* Go through a bunch of insns, converting them to conditional
209 execution format if possible. Return TRUE if all of the non-note
210 insns were processed. */
213 cond_exec_process_insns (start
, end
, test
, prob_val
, mod_ok
)
214 rtx start
; /* first insn to look at */
215 rtx end
; /* last insn to look at */
216 rtx test
; /* conditional execution test */
217 rtx prob_val
; /* probability of branch taken. */
218 int mod_ok
; /* true if modifications ok last insn. */
220 int must_be_last
= FALSE
;
224 for (insn
= start
; ; insn
= NEXT_INSN (insn
))
226 if (GET_CODE (insn
) == NOTE
)
229 if (GET_CODE (insn
) != INSN
&& GET_CODE (insn
) != CALL_INSN
)
232 /* Remove USE insns that get in the way. */
233 if (reload_completed
&& GET_CODE (PATTERN (insn
)) == USE
)
235 /* ??? Ug. Actually unlinking the thing is problematic,
236 given what we'd have to coordinate with our callers. */
237 PUT_CODE (insn
, NOTE
);
238 NOTE_LINE_NUMBER (insn
) = NOTE_INSN_DELETED
;
239 NOTE_SOURCE_FILE (insn
) = 0;
243 /* Last insn wasn't last? */
247 if (modified_in_p (test
, insn
))
254 /* Now build the conditional form of the instruction. */
255 pattern
= PATTERN (insn
);
257 /* If the machine needs to modify the insn being conditionally executed,
258 say for example to force a constant integer operand into a temp
259 register, do so here. */
260 #ifdef IFCVT_MODIFY_INSN
261 IFCVT_MODIFY_INSN (pattern
, insn
);
266 validate_change (insn
, &PATTERN (insn
),
267 gen_rtx_COND_EXEC (VOIDmode
, copy_rtx (test
),
270 if (GET_CODE (insn
) == CALL_INSN
&& prob_val
)
271 validate_change (insn
, ®_NOTES (insn
),
272 alloc_EXPR_LIST (REG_BR_PROB
, prob_val
,
273 REG_NOTES (insn
)), 1);
283 /* Return the condition for a jump. Do not do any special processing. */
286 cond_exec_get_condition (jump
)
291 if (any_condjump_p (jump
))
292 test_if
= SET_SRC (pc_set (jump
));
295 cond
= XEXP (test_if
, 0);
297 /* If this branches to JUMP_LABEL when the condition is false,
298 reverse the condition. */
299 if (GET_CODE (XEXP (test_if
, 2)) == LABEL_REF
300 && XEXP (XEXP (test_if
, 2), 0) == JUMP_LABEL (jump
))
302 enum rtx_code rev
= reversed_comparison_code (cond
, jump
);
306 cond
= gen_rtx_fmt_ee (rev
, GET_MODE (cond
), XEXP (cond
, 0),
313 /* Given a simple IF-THEN or IF-THEN-ELSE block, attempt to convert it
314 to conditional execution. Return TRUE if we were successful at
315 converting the the block. */
318 cond_exec_process_if_block (test_bb
, then_bb
, else_bb
, join_bb
)
319 basic_block test_bb
; /* Basic block test is in */
320 basic_block then_bb
; /* Basic block for THEN block */
321 basic_block else_bb
; /* Basic block for ELSE block */
322 basic_block join_bb
; /* Basic block the join label is in */
324 rtx test_expr
; /* expression in IF_THEN_ELSE that is tested */
325 rtx then_start
; /* first insn in THEN block */
326 rtx then_end
; /* last insn + 1 in THEN block */
327 rtx else_start
= NULL_RTX
; /* first insn in ELSE block or NULL */
328 rtx else_end
= NULL_RTX
; /* last insn + 1 in ELSE block */
329 int max
; /* max # of insns to convert. */
330 int then_mod_ok
; /* whether conditional mods are ok in THEN */
331 rtx true_expr
; /* test for else block insns */
332 rtx false_expr
; /* test for then block insns */
333 rtx true_prob_val
; /* probability of else block */
334 rtx false_prob_val
; /* probability of then block */
336 enum rtx_code false_code
;
338 /* Find the conditional jump to the ELSE or JOIN part, and isolate
340 test_expr
= cond_exec_get_condition (test_bb
->end
);
344 /* If the conditional jump is more than just a conditional jump,
345 then we can not do conditional execution conversion on this block. */
346 if (!onlyjump_p (test_bb
->end
))
349 /* Collect the bounds of where we're to search. */
351 then_start
= then_bb
->head
;
352 then_end
= then_bb
->end
;
354 /* Skip a label heading THEN block. */
355 if (GET_CODE (then_start
) == CODE_LABEL
)
356 then_start
= NEXT_INSN (then_start
);
358 /* Skip a (use (const_int 0)) or branch as the final insn. */
359 if (GET_CODE (then_end
) == INSN
360 && GET_CODE (PATTERN (then_end
)) == USE
361 && GET_CODE (XEXP (PATTERN (then_end
), 0)) == CONST_INT
)
362 then_end
= PREV_INSN (then_end
);
363 else if (GET_CODE (then_end
) == JUMP_INSN
)
364 then_end
= PREV_INSN (then_end
);
368 /* Skip the ELSE block's label. */
369 else_start
= NEXT_INSN (else_bb
->head
);
370 else_end
= else_bb
->end
;
372 /* Skip a (use (const_int 0)) or branch as the final insn. */
373 if (GET_CODE (else_end
) == INSN
374 && GET_CODE (PATTERN (else_end
)) == USE
375 && GET_CODE (XEXP (PATTERN (else_end
), 0)) == CONST_INT
)
376 else_end
= PREV_INSN (else_end
);
377 else if (GET_CODE (else_end
) == JUMP_INSN
)
378 else_end
= PREV_INSN (else_end
);
381 /* How many instructions should we convert in total? */
385 max
= 2 * MAX_CONDITIONAL_EXECUTE
;
386 n_insns
= count_bb_insns (else_bb
);
389 max
= MAX_CONDITIONAL_EXECUTE
;
390 n_insns
+= count_bb_insns (then_bb
);
394 /* Map test_expr/test_jump into the appropriate MD tests to use on
395 the conditionally executed code. */
397 true_expr
= test_expr
;
399 false_code
= reversed_comparison_code (true_expr
, test_bb
->end
);
400 if (false_code
!= UNKNOWN
)
401 false_expr
= gen_rtx_fmt_ee (false_code
, GET_MODE (true_expr
),
402 XEXP (true_expr
, 0), XEXP (true_expr
, 1));
404 false_expr
= NULL_RTX
;
406 #ifdef IFCVT_MODIFY_TESTS
407 /* If the machine description needs to modify the tests, such as setting a
408 conditional execution register from a comparison, it can do so here. */
409 IFCVT_MODIFY_TESTS (true_expr
, false_expr
, test_bb
, then_bb
, else_bb
,
412 /* See if the conversion failed */
413 if (!true_expr
|| !false_expr
)
417 true_prob_val
= find_reg_note (test_bb
->end
, REG_BR_PROB
, NULL_RTX
);
420 true_prob_val
= XEXP (true_prob_val
, 0);
421 false_prob_val
= GEN_INT (REG_BR_PROB_BASE
- INTVAL (true_prob_val
));
424 false_prob_val
= NULL_RTX
;
426 /* For IF-THEN-ELSE blocks, we don't allow modifications of the test
427 on then THEN block. */
428 then_mod_ok
= (else_bb
== NULL_BLOCK
);
430 /* Go through the THEN and ELSE blocks converting the insns if possible
431 to conditional execution. */
435 || ! cond_exec_process_insns (then_start
, then_end
, false_expr
,
436 false_prob_val
, then_mod_ok
)))
440 && ! cond_exec_process_insns (else_start
, else_end
,
441 true_expr
, true_prob_val
, TRUE
))
444 if (! apply_change_group ())
447 #ifdef IFCVT_MODIFY_FINAL
448 /* Do any machine dependent final modifications */
449 IFCVT_MODIFY_FINAL (test_bb
, then_bb
, else_bb
, join_bb
);
452 /* Conversion succeeded. */
454 fprintf (rtl_dump_file
, "%d insn%s converted to conditional execution.\n",
455 n_insns
, (n_insns
== 1) ? " was" : "s were");
457 /* Merge the blocks! */
458 merge_if_block (test_bb
, then_bb
, else_bb
, join_bb
);
462 #ifdef IFCVT_MODIFY_CANCEL
463 /* Cancel any machine dependent changes. */
464 IFCVT_MODIFY_CANCEL (test_bb
, then_bb
, else_bb
, join_bb
);
471 /* Used by noce_process_if_block to communicate with its subroutines.
473 The subroutines know that A and B may be evaluated freely. They
474 know that X is a register. They should insert new instructions
475 before cond_earliest. */
482 rtx jump
, cond
, cond_earliest
;
485 static rtx noce_emit_store_flag
PARAMS ((struct noce_if_info
*,
487 static int noce_try_store_flag
PARAMS ((struct noce_if_info
*));
488 static int noce_try_store_flag_inc
PARAMS ((struct noce_if_info
*));
489 static int noce_try_store_flag_constants
PARAMS ((struct noce_if_info
*));
490 static int noce_try_store_flag_mask
PARAMS ((struct noce_if_info
*));
491 static rtx noce_emit_cmove
PARAMS ((struct noce_if_info
*,
492 rtx
, enum rtx_code
, rtx
,
494 static int noce_try_cmove
PARAMS ((struct noce_if_info
*));
495 static int noce_try_cmove_arith
PARAMS ((struct noce_if_info
*));
496 static rtx noce_get_alt_condition
PARAMS ((struct noce_if_info
*,
498 static int noce_try_minmax
PARAMS ((struct noce_if_info
*));
499 static int noce_try_abs
PARAMS ((struct noce_if_info
*));
501 /* Helper function for noce_try_store_flag*. */
504 noce_emit_store_flag (if_info
, x
, reversep
, normalize
)
505 struct noce_if_info
*if_info
;
507 int reversep
, normalize
;
509 rtx cond
= if_info
->cond
;
513 cond_complex
= (! general_operand (XEXP (cond
, 0), VOIDmode
)
514 || ! general_operand (XEXP (cond
, 1), VOIDmode
));
516 /* If earliest == jump, or when the condition is complex, try to
517 build the store_flag insn directly. */
520 cond
= XEXP (SET_SRC (pc_set (if_info
->jump
)), 0);
523 code
= reversed_comparison_code (cond
, if_info
->jump
);
525 code
= GET_CODE (cond
);
527 if ((if_info
->cond_earliest
== if_info
->jump
|| cond_complex
)
528 && (normalize
== 0 || STORE_FLAG_VALUE
== normalize
))
532 tmp
= gen_rtx_fmt_ee (code
, GET_MODE (x
), XEXP (cond
, 0),
534 tmp
= gen_rtx_SET (VOIDmode
, x
, tmp
);
537 tmp
= emit_insn (tmp
);
539 if (recog_memoized (tmp
) >= 0)
545 if_info
->cond_earliest
= if_info
->jump
;
553 /* Don't even try if the comparison operands are weird. */
557 return emit_store_flag (x
, code
, XEXP (cond
, 0),
558 XEXP (cond
, 1), VOIDmode
,
559 (code
== LTU
|| code
== LEU
560 || code
== GEU
|| code
== GTU
), normalize
);
563 /* Emit instruction to move an rtx into STRICT_LOW_PART. */
565 noce_emit_move_insn (x
, y
)
568 enum machine_mode outmode
, inmode
;
572 if (GET_CODE (x
) != STRICT_LOW_PART
)
574 emit_move_insn (x
, y
);
579 inner
= XEXP (outer
, 0);
580 outmode
= GET_MODE (outer
);
581 inmode
= GET_MODE (inner
);
582 bitpos
= SUBREG_BYTE (outer
) * BITS_PER_UNIT
;
583 store_bit_field (inner
, GET_MODE_BITSIZE (outmode
), bitpos
, outmode
, y
,
584 GET_MODE_BITSIZE (inmode
));
587 /* Convert "if (test) x = 1; else x = 0".
589 Only try 0 and STORE_FLAG_VALUE here. Other combinations will be
590 tried in noce_try_store_flag_constants after noce_try_cmove has had
591 a go at the conversion. */
594 noce_try_store_flag (if_info
)
595 struct noce_if_info
*if_info
;
600 if (GET_CODE (if_info
->b
) == CONST_INT
601 && INTVAL (if_info
->b
) == STORE_FLAG_VALUE
602 && if_info
->a
== const0_rtx
)
604 else if (if_info
->b
== const0_rtx
605 && GET_CODE (if_info
->a
) == CONST_INT
606 && INTVAL (if_info
->a
) == STORE_FLAG_VALUE
607 && (reversed_comparison_code (if_info
->cond
, if_info
->jump
)
615 target
= noce_emit_store_flag (if_info
, if_info
->x
, reversep
, 0);
618 if (target
!= if_info
->x
)
619 noce_emit_move_insn (if_info
->x
, target
);
623 emit_insns_before (seq
, if_info
->cond_earliest
);
634 /* Convert "if (test) x = a; else x = b", for A and B constant. */
637 noce_try_store_flag_constants (if_info
)
638 struct noce_if_info
*if_info
;
642 HOST_WIDE_INT itrue
, ifalse
, diff
, tmp
;
643 int normalize
, can_reverse
;
644 enum machine_mode mode
;
647 && GET_CODE (if_info
->a
) == CONST_INT
648 && GET_CODE (if_info
->b
) == CONST_INT
)
650 mode
= GET_MODE (if_info
->x
);
651 ifalse
= INTVAL (if_info
->a
);
652 itrue
= INTVAL (if_info
->b
);
654 /* Make sure we can represent the difference between the two values. */
655 if ((itrue
- ifalse
> 0)
656 != ((ifalse
< 0) != (itrue
< 0) ? ifalse
< 0 : ifalse
< itrue
))
659 diff
= trunc_int_for_mode (itrue
- ifalse
, mode
);
661 can_reverse
= (reversed_comparison_code (if_info
->cond
, if_info
->jump
)
665 if (diff
== STORE_FLAG_VALUE
|| diff
== -STORE_FLAG_VALUE
)
667 else if (ifalse
== 0 && exact_log2 (itrue
) >= 0
668 && (STORE_FLAG_VALUE
== 1
669 || BRANCH_COST
>= 2))
671 else if (itrue
== 0 && exact_log2 (ifalse
) >= 0 && can_reverse
672 && (STORE_FLAG_VALUE
== 1 || BRANCH_COST
>= 2))
673 normalize
= 1, reversep
= 1;
675 && (STORE_FLAG_VALUE
== -1
676 || BRANCH_COST
>= 2))
678 else if (ifalse
== -1 && can_reverse
679 && (STORE_FLAG_VALUE
== -1 || BRANCH_COST
>= 2))
680 normalize
= -1, reversep
= 1;
681 else if ((BRANCH_COST
>= 2 && STORE_FLAG_VALUE
== -1)
689 tmp
= itrue
; itrue
= ifalse
; ifalse
= tmp
;
690 diff
= trunc_int_for_mode (-diff
, mode
);
694 target
= noce_emit_store_flag (if_info
, if_info
->x
, reversep
, normalize
);
701 /* if (test) x = 3; else x = 4;
702 => x = 3 + (test == 0); */
703 if (diff
== STORE_FLAG_VALUE
|| diff
== -STORE_FLAG_VALUE
)
705 target
= expand_simple_binop (mode
,
706 (diff
== STORE_FLAG_VALUE
708 GEN_INT (ifalse
), target
, if_info
->x
, 0,
712 /* if (test) x = 8; else x = 0;
713 => x = (test != 0) << 3; */
714 else if (ifalse
== 0 && (tmp
= exact_log2 (itrue
)) >= 0)
716 target
= expand_simple_binop (mode
, ASHIFT
,
717 target
, GEN_INT (tmp
), if_info
->x
, 0,
721 /* if (test) x = -1; else x = b;
722 => x = -(test != 0) | b; */
723 else if (itrue
== -1)
725 target
= expand_simple_binop (mode
, IOR
,
726 target
, GEN_INT (ifalse
), if_info
->x
, 0,
730 /* if (test) x = a; else x = b;
731 => x = (-(test != 0) & (b - a)) + a; */
734 target
= expand_simple_binop (mode
, AND
,
735 target
, GEN_INT (diff
), if_info
->x
, 0,
738 target
= expand_simple_binop (mode
, PLUS
,
739 target
, GEN_INT (ifalse
),
740 if_info
->x
, 0, OPTAB_WIDEN
);
749 if (target
!= if_info
->x
)
750 noce_emit_move_insn (if_info
->x
, target
);
755 if (seq_contains_jump (seq
))
758 emit_insns_before (seq
, if_info
->cond_earliest
);
766 /* Convert "if (test) foo++" into "foo += (test != 0)", and
767 similarly for "foo--". */
770 noce_try_store_flag_inc (if_info
)
771 struct noce_if_info
*if_info
;
774 int subtract
, normalize
;
780 /* Should be no `else' case to worry about. */
781 && if_info
->b
== if_info
->x
782 && GET_CODE (if_info
->a
) == PLUS
783 && (XEXP (if_info
->a
, 1) == const1_rtx
784 || XEXP (if_info
->a
, 1) == constm1_rtx
)
785 && rtx_equal_p (XEXP (if_info
->a
, 0), if_info
->x
)
786 && (reversed_comparison_code (if_info
->cond
, if_info
->jump
)
789 if (STORE_FLAG_VALUE
== INTVAL (XEXP (if_info
->a
, 1)))
790 subtract
= 0, normalize
= 0;
791 else if (-STORE_FLAG_VALUE
== INTVAL (XEXP (if_info
->a
, 1)))
792 subtract
= 1, normalize
= 0;
794 subtract
= 0, normalize
= INTVAL (XEXP (if_info
->a
, 1));
798 target
= noce_emit_store_flag (if_info
,
799 gen_reg_rtx (GET_MODE (if_info
->x
)),
803 target
= expand_simple_binop (GET_MODE (if_info
->x
),
804 subtract
? MINUS
: PLUS
,
805 if_info
->x
, target
, if_info
->x
,
809 if (target
!= if_info
->x
)
810 noce_emit_move_insn (if_info
->x
, target
);
815 if (seq_contains_jump (seq
))
818 emit_insns_before (seq
, if_info
->cond_earliest
);
829 /* Convert "if (test) x = 0;" to "x &= -(test == 0);" */
832 noce_try_store_flag_mask (if_info
)
833 struct noce_if_info
*if_info
;
841 || STORE_FLAG_VALUE
== -1)
842 && ((if_info
->a
== const0_rtx
843 && rtx_equal_p (if_info
->b
, if_info
->x
))
844 || ((reversep
= (reversed_comparison_code (if_info
->cond
,
847 && if_info
->b
== const0_rtx
848 && rtx_equal_p (if_info
->a
, if_info
->x
))))
851 target
= noce_emit_store_flag (if_info
,
852 gen_reg_rtx (GET_MODE (if_info
->x
)),
855 target
= expand_simple_binop (GET_MODE (if_info
->x
), AND
,
856 if_info
->x
, target
, if_info
->x
, 0,
861 if (target
!= if_info
->x
)
862 noce_emit_move_insn (if_info
->x
, target
);
867 if (seq_contains_jump (seq
))
870 emit_insns_before (seq
, if_info
->cond_earliest
);
881 /* Helper function for noce_try_cmove and noce_try_cmove_arith. */
884 noce_emit_cmove (if_info
, x
, code
, cmp_a
, cmp_b
, vfalse
, vtrue
)
885 struct noce_if_info
*if_info
;
886 rtx x
, cmp_a
, cmp_b
, vfalse
, vtrue
;
889 /* If earliest == jump, try to build the cmove insn directly.
890 This is helpful when combine has created some complex condition
891 (like for alpha's cmovlbs) that we can't hope to regenerate
892 through the normal interface. */
894 if (if_info
->cond_earliest
== if_info
->jump
)
898 tmp
= gen_rtx_fmt_ee (code
, GET_MODE (if_info
->cond
), cmp_a
, cmp_b
);
899 tmp
= gen_rtx_IF_THEN_ELSE (GET_MODE (x
), tmp
, vtrue
, vfalse
);
900 tmp
= gen_rtx_SET (VOIDmode
, x
, tmp
);
903 tmp
= emit_insn (tmp
);
905 if (recog_memoized (tmp
) >= 0)
917 /* Don't even try if the comparison operands are weird. */
918 if (! general_operand (cmp_a
, GET_MODE (cmp_a
))
919 || ! general_operand (cmp_b
, GET_MODE (cmp_b
)))
922 #if HAVE_conditional_move
923 return emit_conditional_move (x
, code
, cmp_a
, cmp_b
, VOIDmode
,
924 vtrue
, vfalse
, GET_MODE (x
),
925 (code
== LTU
|| code
== GEU
926 || code
== LEU
|| code
== GTU
));
928 /* We'll never get here, as noce_process_if_block doesn't call the
929 functions involved. Ifdef code, however, should be discouraged
930 because it leads to typos in the code not selected. However,
931 emit_conditional_move won't exist either. */
936 /* Try only simple constants and registers here. More complex cases
937 are handled in noce_try_cmove_arith after noce_try_store_flag_arith
938 has had a go at it. */
941 noce_try_cmove (if_info
)
942 struct noce_if_info
*if_info
;
947 if ((CONSTANT_P (if_info
->a
) || register_operand (if_info
->a
, VOIDmode
))
948 && (CONSTANT_P (if_info
->b
) || register_operand (if_info
->b
, VOIDmode
)))
952 code
= GET_CODE (if_info
->cond
);
953 target
= noce_emit_cmove (if_info
, if_info
->x
, code
,
954 XEXP (if_info
->cond
, 0),
955 XEXP (if_info
->cond
, 1),
956 if_info
->a
, if_info
->b
);
960 if (target
!= if_info
->x
)
961 noce_emit_move_insn (if_info
->x
, target
);
965 emit_insns_before (seq
, if_info
->cond_earliest
);
978 /* Try more complex cases involving conditional_move. */
981 noce_try_cmove_arith (if_info
)
982 struct noce_if_info
*if_info
;
992 /* A conditional move from two memory sources is equivalent to a
993 conditional on their addresses followed by a load. Don't do this
994 early because it'll screw alias analysis. Note that we've
995 already checked for no side effects. */
996 if (! no_new_pseudos
&& cse_not_expected
997 && GET_CODE (a
) == MEM
&& GET_CODE (b
) == MEM
1002 x
= gen_reg_rtx (Pmode
);
1006 /* ??? We could handle this if we knew that a load from A or B could
1007 not fault. This is also true if we've already loaded
1008 from the address along the path from ENTRY. */
1009 else if (may_trap_p (a
) || may_trap_p (b
))
1012 /* if (test) x = a + b; else x = c - d;
1019 code
= GET_CODE (if_info
->cond
);
1020 insn_a
= if_info
->insn_a
;
1021 insn_b
= if_info
->insn_b
;
1023 /* Possibly rearrange operands to make things come out more natural. */
1024 if (reversed_comparison_code (if_info
->cond
, if_info
->jump
) != UNKNOWN
)
1027 if (rtx_equal_p (b
, x
))
1029 else if (general_operand (b
, GET_MODE (b
)))
1034 code
= reversed_comparison_code (if_info
->cond
, if_info
->jump
);
1035 tmp
= a
, a
= b
, b
= tmp
;
1036 tmp
= insn_a
, insn_a
= insn_b
, insn_b
= tmp
;
1042 /* If either operand is complex, load it into a register first.
1043 The best way to do this is to copy the original insn. In this
1044 way we preserve any clobbers etc that the insn may have had.
1045 This is of course not possible in the IS_MEM case. */
1046 if (! general_operand (a
, GET_MODE (a
)))
1051 goto end_seq_and_fail
;
1055 tmp
= gen_reg_rtx (GET_MODE (a
));
1056 tmp
= emit_insn (gen_rtx_SET (VOIDmode
, tmp
, a
));
1059 goto end_seq_and_fail
;
1062 a
= gen_reg_rtx (GET_MODE (a
));
1063 tmp
= copy_rtx (insn_a
);
1064 set
= single_set (tmp
);
1066 tmp
= emit_insn (PATTERN (tmp
));
1068 if (recog_memoized (tmp
) < 0)
1069 goto end_seq_and_fail
;
1071 if (! general_operand (b
, GET_MODE (b
)))
1076 goto end_seq_and_fail
;
1080 tmp
= gen_reg_rtx (GET_MODE (b
));
1081 tmp
= emit_insn (gen_rtx_SET (VOIDmode
, tmp
, b
));
1084 goto end_seq_and_fail
;
1087 b
= gen_reg_rtx (GET_MODE (b
));
1088 tmp
= copy_rtx (insn_b
);
1089 set
= single_set (tmp
);
1091 tmp
= emit_insn (PATTERN (tmp
));
1093 if (recog_memoized (tmp
) < 0)
1094 goto end_seq_and_fail
;
1097 target
= noce_emit_cmove (if_info
, x
, code
, XEXP (if_info
->cond
, 0),
1098 XEXP (if_info
->cond
, 1), a
, b
);
1101 goto end_seq_and_fail
;
1103 /* If we're handling a memory for above, emit the load now. */
1106 tmp
= gen_rtx_MEM (GET_MODE (if_info
->x
), target
);
1108 /* Copy over flags as appropriate. */
1109 if (MEM_VOLATILE_P (if_info
->a
) || MEM_VOLATILE_P (if_info
->b
))
1110 MEM_VOLATILE_P (tmp
) = 1;
1111 if (MEM_IN_STRUCT_P (if_info
->a
) && MEM_IN_STRUCT_P (if_info
->b
))
1112 MEM_IN_STRUCT_P (tmp
) = 1;
1113 if (MEM_SCALAR_P (if_info
->a
) && MEM_SCALAR_P (if_info
->b
))
1114 MEM_SCALAR_P (tmp
) = 1;
1115 if (MEM_ALIAS_SET (if_info
->a
) == MEM_ALIAS_SET (if_info
->b
))
1116 set_mem_alias_set (tmp
, MEM_ALIAS_SET (if_info
->a
));
1118 MIN (MEM_ALIGN (if_info
->a
), MEM_ALIGN (if_info
->b
)));
1120 noce_emit_move_insn (if_info
->x
, tmp
);
1122 else if (target
!= x
)
1123 noce_emit_move_insn (x
, target
);
1127 emit_insns_before (tmp
, if_info
->cond_earliest
);
1135 /* For most cases, the simplified condition we found is the best
1136 choice, but this is not the case for the min/max/abs transforms.
1137 For these we wish to know that it is A or B in the condition. */
1140 noce_get_alt_condition (if_info
, target
, earliest
)
1141 struct noce_if_info
*if_info
;
1145 rtx cond
, set
, insn
;
1148 /* If target is already mentioned in the known condition, return it. */
1149 if (reg_mentioned_p (target
, if_info
->cond
))
1151 *earliest
= if_info
->cond_earliest
;
1152 return if_info
->cond
;
1155 set
= pc_set (if_info
->jump
);
1156 cond
= XEXP (SET_SRC (set
), 0);
1158 = GET_CODE (XEXP (SET_SRC (set
), 2)) == LABEL_REF
1159 && XEXP (XEXP (SET_SRC (set
), 2), 0) == JUMP_LABEL (if_info
->jump
);
1161 /* If we're looking for a constant, try to make the conditional
1162 have that constant in it. There are two reasons why it may
1163 not have the constant we want:
1165 1. GCC may have needed to put the constant in a register, because
1166 the target can't compare directly against that constant. For
1167 this case, we look for a SET immediately before the comparison
1168 that puts a constant in that register.
1170 2. GCC may have canonicalized the conditional, for example
1171 replacing "if x < 4" with "if x <= 3". We can undo that (or
1172 make equivalent types of changes) to get the constants we need
1173 if they're off by one in the right direction. */
1175 if (GET_CODE (target
) == CONST_INT
)
1177 enum rtx_code code
= GET_CODE (if_info
->cond
);
1178 rtx op_a
= XEXP (if_info
->cond
, 0);
1179 rtx op_b
= XEXP (if_info
->cond
, 1);
1182 /* First, look to see if we put a constant in a register. */
1183 prev_insn
= PREV_INSN (if_info
->cond_earliest
);
1185 && INSN_P (prev_insn
)
1186 && GET_CODE (PATTERN (prev_insn
)) == SET
)
1188 rtx src
= find_reg_equal_equiv_note (prev_insn
);
1190 src
= SET_SRC (PATTERN (prev_insn
));
1191 if (GET_CODE (src
) == CONST_INT
)
1193 if (rtx_equal_p (op_a
, SET_DEST (PATTERN (prev_insn
))))
1195 else if (rtx_equal_p (op_b
, SET_DEST (PATTERN (prev_insn
))))
1198 if (GET_CODE (op_a
) == CONST_INT
)
1203 code
= swap_condition (code
);
1208 /* Now, look to see if we can get the right constant by
1209 adjusting the conditional. */
1210 if (GET_CODE (op_b
) == CONST_INT
)
1212 HOST_WIDE_INT desired_val
= INTVAL (target
);
1213 HOST_WIDE_INT actual_val
= INTVAL (op_b
);
1218 if (actual_val
== desired_val
+ 1)
1221 op_b
= GEN_INT (desired_val
);
1225 if (actual_val
== desired_val
- 1)
1228 op_b
= GEN_INT (desired_val
);
1232 if (actual_val
== desired_val
- 1)
1235 op_b
= GEN_INT (desired_val
);
1239 if (actual_val
== desired_val
+ 1)
1242 op_b
= GEN_INT (desired_val
);
1250 /* If we made any changes, generate a new conditional that is
1251 equivalent to what we started with, but has the right
1253 if (code
!= GET_CODE (if_info
->cond
)
1254 || op_a
!= XEXP (if_info
->cond
, 0)
1255 || op_b
!= XEXP (if_info
->cond
, 1))
1257 cond
= gen_rtx_fmt_ee (code
, GET_MODE (cond
), op_a
, op_b
);
1258 *earliest
= if_info
->cond_earliest
;
1263 cond
= canonicalize_condition (if_info
->jump
, cond
, reverse
,
1265 if (! cond
|| ! reg_mentioned_p (target
, cond
))
1268 /* We almost certainly searched back to a different place.
1269 Need to re-verify correct lifetimes. */
1271 /* X may not be mentioned in the range (cond_earliest, jump]. */
1272 for (insn
= if_info
->jump
; insn
!= *earliest
; insn
= PREV_INSN (insn
))
1273 if (INSN_P (insn
) && reg_mentioned_p (if_info
->x
, insn
))
1276 /* A and B may not be modified in the range [cond_earliest, jump). */
1277 for (insn
= *earliest
; insn
!= if_info
->jump
; insn
= NEXT_INSN (insn
))
1279 && (modified_in_p (if_info
->a
, insn
)
1280 || modified_in_p (if_info
->b
, insn
)))
1286 /* Convert "if (a < b) x = a; else x = b;" to "x = min(a, b);", etc. */
1289 noce_try_minmax (if_info
)
1290 struct noce_if_info
*if_info
;
1292 rtx cond
, earliest
, target
, seq
;
1293 enum rtx_code code
, op
;
1296 /* ??? Can't guarantee that expand_binop won't create pseudos. */
1300 /* ??? Reject FP modes since we don't know how 0 vs -0 or NaNs
1301 will be resolved with an SMIN/SMAX. It wouldn't be too hard
1302 to get the target to tell us... */
1303 if (FLOAT_MODE_P (GET_MODE (if_info
->x
))
1304 && TARGET_FLOAT_FORMAT
== IEEE_FLOAT_FORMAT
1305 && ! flag_unsafe_math_optimizations
)
1308 cond
= noce_get_alt_condition (if_info
, if_info
->a
, &earliest
);
1312 /* Verify the condition is of the form we expect, and canonicalize
1313 the comparison code. */
1314 code
= GET_CODE (cond
);
1315 if (rtx_equal_p (XEXP (cond
, 0), if_info
->a
))
1317 if (! rtx_equal_p (XEXP (cond
, 1), if_info
->b
))
1320 else if (rtx_equal_p (XEXP (cond
, 1), if_info
->a
))
1322 if (! rtx_equal_p (XEXP (cond
, 0), if_info
->b
))
1324 code
= swap_condition (code
);
1329 /* Determine what sort of operation this is. Note that the code is for
1330 a taken branch, so the code->operation mapping appears backwards. */
1363 target
= expand_simple_binop (GET_MODE (if_info
->x
), op
,
1364 if_info
->a
, if_info
->b
,
1365 if_info
->x
, unsignedp
, OPTAB_WIDEN
);
1371 if (target
!= if_info
->x
)
1372 noce_emit_move_insn (if_info
->x
, target
);
1377 if (seq_contains_jump (seq
))
1380 emit_insns_before (seq
, earliest
);
1381 if_info
->cond
= cond
;
1382 if_info
->cond_earliest
= earliest
;
1387 /* Convert "if (a < 0) x = -a; else x = a;" to "x = abs(a);", etc. */
1390 noce_try_abs (if_info
)
1391 struct noce_if_info
*if_info
;
1393 rtx cond
, earliest
, target
, seq
, a
, b
, c
;
1396 /* ??? Can't guarantee that expand_binop won't create pseudos. */
1400 /* Recognize A and B as constituting an ABS or NABS. */
1403 if (GET_CODE (a
) == NEG
&& rtx_equal_p (XEXP (a
, 0), b
))
1405 else if (GET_CODE (b
) == NEG
&& rtx_equal_p (XEXP (b
, 0), a
))
1407 c
= a
; a
= b
; b
= c
;
1413 cond
= noce_get_alt_condition (if_info
, b
, &earliest
);
1417 /* Verify the condition is of the form we expect. */
1418 if (rtx_equal_p (XEXP (cond
, 0), b
))
1420 else if (rtx_equal_p (XEXP (cond
, 1), b
))
1425 /* Verify that C is zero. Search backward through the block for
1426 a REG_EQUAL note if necessary. */
1429 rtx insn
, note
= NULL
;
1430 for (insn
= earliest
;
1431 insn
!= if_info
->test_bb
->head
;
1432 insn
= PREV_INSN (insn
))
1434 && ((note
= find_reg_note (insn
, REG_EQUAL
, c
))
1435 || (note
= find_reg_note (insn
, REG_EQUIV
, c
))))
1441 if (GET_CODE (c
) == MEM
1442 && GET_CODE (XEXP (c
, 0)) == SYMBOL_REF
1443 && CONSTANT_POOL_ADDRESS_P (XEXP (c
, 0)))
1444 c
= get_pool_constant (XEXP (c
, 0));
1446 /* Work around funny ideas get_condition has wrt canonicalization.
1447 Note that these rtx constants are known to be CONST_INT, and
1448 therefore imply integer comparisons. */
1449 if (c
== constm1_rtx
&& GET_CODE (cond
) == GT
)
1451 else if (c
== const1_rtx
&& GET_CODE (cond
) == LT
)
1453 else if (c
!= CONST0_RTX (GET_MODE (b
)))
1456 /* Determine what sort of operation this is. */
1457 switch (GET_CODE (cond
))
1476 target
= expand_simple_unop (GET_MODE (if_info
->x
), ABS
, b
, if_info
->x
, 0);
1478 /* ??? It's a quandry whether cmove would be better here, especially
1479 for integers. Perhaps combine will clean things up. */
1480 if (target
&& negate
)
1481 target
= expand_simple_unop (GET_MODE (target
), NEG
, target
, if_info
->x
, 0);
1489 if (target
!= if_info
->x
)
1490 noce_emit_move_insn (if_info
->x
, target
);
1495 if (seq_contains_jump (seq
))
1498 emit_insns_before (seq
, earliest
);
1499 if_info
->cond
= cond
;
1500 if_info
->cond_earliest
= earliest
;
1505 /* Look for the condition for the jump first. We'd prefer to avoid
1506 get_condition if we can -- it tries to look back for the contents
1507 of an original compare. On targets that use normal integers for
1508 comparisons, e.g. alpha, this is wasteful. */
1511 noce_get_condition (jump
, earliest
)
1518 /* If the condition variable is a register and is MODE_INT, accept it.
1519 Otherwise, fall back on get_condition. */
1521 if (! any_condjump_p (jump
))
1524 set
= pc_set (jump
);
1526 cond
= XEXP (SET_SRC (set
), 0);
1527 if (GET_CODE (XEXP (cond
, 0)) == REG
1528 && GET_MODE_CLASS (GET_MODE (XEXP (cond
, 0))) == MODE_INT
)
1532 /* If this branches to JUMP_LABEL when the condition is false,
1533 reverse the condition. */
1534 if (GET_CODE (XEXP (SET_SRC (set
), 2)) == LABEL_REF
1535 && XEXP (XEXP (SET_SRC (set
), 2), 0) == JUMP_LABEL (jump
))
1536 cond
= gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond
)),
1537 GET_MODE (cond
), XEXP (cond
, 0),
1541 cond
= get_condition (jump
, earliest
);
1546 /* Return true if OP is ok for if-then-else processing. */
1549 noce_operand_ok (op
)
1552 /* We special-case memories, so handle any of them with
1553 no address side effects. */
1554 if (GET_CODE (op
) == MEM
)
1555 return ! side_effects_p (XEXP (op
, 0));
1557 if (side_effects_p (op
))
1560 /* ??? Unfortuantely may_trap_p can't look at flag_trapping_math, due to
1561 being linked into the genfoo programs. This is probably a mistake.
1562 With finite operands, most fp operations don't trap. */
1563 if (!flag_trapping_math
&& FLOAT_MODE_P (GET_MODE (op
)))
1564 switch (GET_CODE (op
))
1570 /* ??? This is kinda lame -- almost every target will have forced
1571 the constant into a register first. But given the expense of
1572 division, this is probably for the best. */
1573 return (CONSTANT_P (XEXP (op
, 1))
1574 && XEXP (op
, 1) != CONST0_RTX (GET_MODE (op
))
1575 && ! may_trap_p (XEXP (op
, 0)));
1578 switch (GET_RTX_CLASS (GET_CODE (op
)))
1581 return ! may_trap_p (XEXP (op
, 0));
1584 return ! may_trap_p (XEXP (op
, 0)) && ! may_trap_p (XEXP (op
, 1));
1589 return ! may_trap_p (op
);
1592 /* Given a simple IF-THEN or IF-THEN-ELSE block, attempt to convert it
1593 without using conditional execution. Return TRUE if we were
1594 successful at converting the the block. */
1597 noce_process_if_block (test_bb
, then_bb
, else_bb
, join_bb
)
1598 basic_block test_bb
; /* Basic block test is in */
1599 basic_block then_bb
; /* Basic block for THEN block */
1600 basic_block else_bb
; /* Basic block for ELSE block */
1601 basic_block join_bb
; /* Basic block the join label is in */
1603 /* We're looking for patterns of the form
1605 (1) if (...) x = a; else x = b;
1606 (2) x = b; if (...) x = a;
1607 (3) if (...) x = a; // as if with an initial x = x.
1609 The later patterns require jumps to be more expensive.
1611 ??? For future expansion, look for multiple X in such patterns. */
1613 struct noce_if_info if_info
;
1616 rtx orig_x
, x
, a
, b
;
1617 rtx jump
, cond
, insn
;
1619 /* If this is not a standard conditional jump, we can't parse it. */
1620 jump
= test_bb
->end
;
1621 cond
= noce_get_condition (jump
, &if_info
.cond_earliest
);
1625 /* If the conditional jump is more than just a conditional jump,
1626 then we can not do if-conversion on this block. */
1627 if (! onlyjump_p (jump
))
1630 /* We must be comparing objects whose modes imply the size. */
1631 if (GET_MODE (XEXP (cond
, 0)) == BLKmode
)
1634 /* Look for one of the potential sets. */
1635 insn_a
= first_active_insn (then_bb
);
1637 || ! last_active_insn_p (then_bb
, insn_a
)
1638 || (set_a
= single_set (insn_a
)) == NULL_RTX
)
1641 x
= SET_DEST (set_a
);
1642 a
= SET_SRC (set_a
);
1644 /* Look for the other potential set. Make sure we've got equivalent
1646 /* ??? This is overconservative. Storing to two different mems is
1647 as easy as conditionally computing the address. Storing to a
1648 single mem merely requires a scratch memory to use as one of the
1649 destination addresses; often the memory immediately below the
1650 stack pointer is available for this. */
1654 insn_b
= first_active_insn (else_bb
);
1656 || ! last_active_insn_p (else_bb
, insn_b
)
1657 || (set_b
= single_set (insn_b
)) == NULL_RTX
1658 || ! rtx_equal_p (x
, SET_DEST (set_b
)))
1663 insn_b
= prev_nonnote_insn (if_info
.cond_earliest
);
1665 || GET_CODE (insn_b
) != INSN
1666 || (set_b
= single_set (insn_b
)) == NULL_RTX
1667 || ! rtx_equal_p (x
, SET_DEST (set_b
))
1668 || reg_mentioned_p (x
, cond
)
1669 || reg_mentioned_p (x
, a
)
1670 || reg_mentioned_p (x
, SET_SRC (set_b
)))
1671 insn_b
= set_b
= NULL_RTX
;
1673 b
= (set_b
? SET_SRC (set_b
) : x
);
1675 /* X may not be mentioned in the range (cond_earliest, jump]. */
1676 for (insn
= jump
; insn
!= if_info
.cond_earliest
; insn
= PREV_INSN (insn
))
1677 if (INSN_P (insn
) && reg_mentioned_p (x
, insn
))
1680 /* A and B may not be modified in the range [cond_earliest, jump). */
1681 for (insn
= if_info
.cond_earliest
; insn
!= jump
; insn
= NEXT_INSN (insn
))
1683 && (modified_in_p (a
, insn
) || modified_in_p (b
, insn
)))
1686 /* Only operate on register destinations, and even then avoid extending
1687 the lifetime of hard registers on small register class machines. */
1689 if (GET_CODE (x
) != REG
1690 || (SMALL_REGISTER_CLASSES
1691 && REGNO (x
) < FIRST_PSEUDO_REGISTER
))
1695 x
= gen_reg_rtx (GET_MODE (GET_CODE (x
) == STRICT_LOW_PART
1696 ? XEXP (x
, 0) : x
));
1699 /* Don't operate on sources that may trap or are volatile. */
1700 if (! noce_operand_ok (a
) || ! noce_operand_ok (b
))
1703 /* Set up the info block for our subroutines. */
1704 if_info
.test_bb
= test_bb
;
1705 if_info
.cond
= cond
;
1706 if_info
.jump
= jump
;
1707 if_info
.insn_a
= insn_a
;
1708 if_info
.insn_b
= insn_b
;
1713 /* Try optimizations in some approximation of a useful order. */
1714 /* ??? Should first look to see if X is live incoming at all. If it
1715 isn't, we don't need anything but an unconditional set. */
1717 /* Look and see if A and B are really the same. Avoid creating silly
1718 cmove constructs that no one will fix up later. */
1719 if (rtx_equal_p (a
, b
))
1721 /* If we have an INSN_B, we don't have to create any new rtl. Just
1722 move the instruction that we already have. If we don't have an
1723 INSN_B, that means that A == X, and we've got a noop move. In
1724 that case don't do anything and let the code below delete INSN_A. */
1725 if (insn_b
&& else_bb
)
1729 if (else_bb
&& insn_b
== else_bb
->end
)
1730 else_bb
->end
= PREV_INSN (insn_b
);
1731 reorder_insns (insn_b
, insn_b
, PREV_INSN (if_info
.cond_earliest
));
1733 /* If there was a REG_EQUAL note, delete it since it may have been
1734 true due to this insn being after a jump. */
1735 if ((note
= find_reg_note (insn_b
, REG_EQUAL
, NULL_RTX
)) != 0)
1736 remove_note (insn_b
, note
);
1740 /* If we have "x = b; if (...) x = a;", and x has side-effects, then
1741 x must be executed twice. */
1742 else if (insn_b
&& side_effects_p (orig_x
))
1749 if (noce_try_store_flag (&if_info
))
1751 if (noce_try_minmax (&if_info
))
1753 if (noce_try_abs (&if_info
))
1755 if (HAVE_conditional_move
1756 && noce_try_cmove (&if_info
))
1758 if (! HAVE_conditional_execution
)
1760 if (noce_try_store_flag_constants (&if_info
))
1762 if (noce_try_store_flag_inc (&if_info
))
1764 if (noce_try_store_flag_mask (&if_info
))
1766 if (HAVE_conditional_move
1767 && noce_try_cmove_arith (&if_info
))
1774 /* The original sets may now be killed. */
1775 delete_insn (insn_a
);
1777 /* Several special cases here: First, we may have reused insn_b above,
1778 in which case insn_b is now NULL. Second, we want to delete insn_b
1779 if it came from the ELSE block, because follows the now correct
1780 write that appears in the TEST block. However, if we got insn_b from
1781 the TEST block, it may in fact be loading data needed for the comparison.
1782 We'll let life_analysis remove the insn if it's really dead. */
1783 if (insn_b
&& else_bb
)
1784 delete_insn (insn_b
);
1786 /* The new insns will have been inserted before cond_earliest. We should
1787 be able to remove the jump with impunity, but the condition itself may
1788 have been modified by gcse to be shared across basic blocks. */
1791 /* If we used a temporary, fix it up now. */
1795 noce_emit_move_insn (orig_x
, x
);
1796 insn_b
= gen_sequence ();
1799 emit_insn_after (insn_b
, test_bb
->end
);
1802 /* Merge the blocks! */
1803 merge_if_block (test_bb
, then_bb
, else_bb
, join_bb
);
1808 /* Attempt to convert an IF-THEN or IF-THEN-ELSE block into
1809 straight line code. Return true if successful. */
1812 process_if_block (test_bb
, then_bb
, else_bb
, join_bb
)
1813 basic_block test_bb
; /* Basic block test is in */
1814 basic_block then_bb
; /* Basic block for THEN block */
1815 basic_block else_bb
; /* Basic block for ELSE block */
1816 basic_block join_bb
; /* Basic block the join label is in */
1818 if (! reload_completed
1819 && noce_process_if_block (test_bb
, then_bb
, else_bb
, join_bb
))
1822 if (HAVE_conditional_execution
1824 && cond_exec_process_if_block (test_bb
, then_bb
, else_bb
, join_bb
))
1830 /* Merge the blocks and mark for local life update. */
1833 merge_if_block (test_bb
, then_bb
, else_bb
, join_bb
)
1834 basic_block test_bb
; /* Basic block test is in */
1835 basic_block then_bb
; /* Basic block for THEN block */
1836 basic_block else_bb
; /* Basic block for ELSE block */
1837 basic_block join_bb
; /* Basic block the join label is in */
1839 basic_block combo_bb
;
1841 /* All block merging is done into the lower block numbers. */
1845 /* First merge TEST block into THEN block. This is a no-brainer since
1846 the THEN block did not have a code label to begin with. */
1849 COPY_REG_SET (combo_bb
->global_live_at_end
, then_bb
->global_live_at_end
);
1850 merge_blocks_nomove (combo_bb
, then_bb
);
1851 num_removed_blocks
++;
1853 /* The ELSE block, if it existed, had a label. That label count
1854 will almost always be zero, but odd things can happen when labels
1855 get their addresses taken. */
1858 merge_blocks_nomove (combo_bb
, else_bb
);
1859 num_removed_blocks
++;
1862 /* If there was no join block reported, that means it was not adjacent
1863 to the others, and so we cannot merge them. */
1867 /* The outgoing edge for the current COMBO block should already
1868 be correct. Verify this. */
1869 if (combo_bb
->succ
== NULL_EDGE
)
1872 /* There should still be a branch at the end of the THEN or ELSE
1873 blocks taking us to our final destination. */
1874 if (GET_CODE (combo_bb
->end
) != JUMP_INSN
)
1878 /* The JOIN block may have had quite a number of other predecessors too.
1879 Since we've already merged the TEST, THEN and ELSE blocks, we should
1880 have only one remaining edge from our if-then-else diamond. If there
1881 is more than one remaining edge, it must come from elsewhere. There
1882 may be zero incoming edges if the THEN block didn't actually join
1883 back up (as with a call to abort). */
1884 else if ((join_bb
->pred
== NULL
1885 || join_bb
->pred
->pred_next
== NULL
)
1886 && join_bb
!= EXIT_BLOCK_PTR
)
1888 /* We can merge the JOIN. */
1890 COPY_REG_SET (combo_bb
->global_live_at_end
,
1891 join_bb
->global_live_at_end
);
1892 merge_blocks_nomove (combo_bb
, join_bb
);
1893 num_removed_blocks
++;
1897 /* We cannot merge the JOIN. */
1899 /* The outgoing edge for the current COMBO block should already
1900 be correct. Verify this. */
1901 if (combo_bb
->succ
->succ_next
!= NULL_EDGE
1902 || combo_bb
->succ
->dest
!= join_bb
)
1905 /* Remove the jump and cruft from the end of the COMBO block. */
1906 if (join_bb
!= EXIT_BLOCK_PTR
)
1907 tidy_fallthru_edge (combo_bb
->succ
, combo_bb
, join_bb
);
1910 /* Make sure we update life info properly. */
1911 SET_UPDATE_LIFE (combo_bb
);
1913 num_updated_if_blocks
++;
1916 /* Find a block ending in a simple IF condition. Return TRUE if
1917 we were able to transform it in some way. */
1920 find_if_header (test_bb
)
1921 basic_block test_bb
;
1926 /* The kind of block we're looking for has exactly two successors. */
1927 if ((then_edge
= test_bb
->succ
) == NULL_EDGE
1928 || (else_edge
= then_edge
->succ_next
) == NULL_EDGE
1929 || else_edge
->succ_next
!= NULL_EDGE
)
1932 /* Neither edge should be abnormal. */
1933 if ((then_edge
->flags
& EDGE_COMPLEX
)
1934 || (else_edge
->flags
& EDGE_COMPLEX
))
1937 /* The THEN edge is canonically the one that falls through. */
1938 if (then_edge
->flags
& EDGE_FALLTHRU
)
1940 else if (else_edge
->flags
& EDGE_FALLTHRU
)
1943 else_edge
= then_edge
;
1947 /* Otherwise this must be a multiway branch of some sort. */
1950 if (find_if_block (test_bb
, then_edge
, else_edge
))
1952 if (HAVE_trap
&& HAVE_conditional_trap
1953 && find_cond_trap (test_bb
, then_edge
, else_edge
))
1956 && (! HAVE_conditional_execution
|| reload_completed
))
1958 if (find_if_case_1 (test_bb
, then_edge
, else_edge
))
1960 if (find_if_case_2 (test_bb
, then_edge
, else_edge
))
1968 fprintf (rtl_dump_file
, "Conversion succeeded.\n");
1972 /* Determine if a given basic block heads a simple IF-THEN or IF-THEN-ELSE
1973 block. If so, we'll try to convert the insns to not require the branch.
1974 Return TRUE if we were successful at converting the the block. */
1977 find_if_block (test_bb
, then_edge
, else_edge
)
1978 basic_block test_bb
;
1979 edge then_edge
, else_edge
;
1981 basic_block then_bb
= then_edge
->dest
;
1982 basic_block else_bb
= else_edge
->dest
;
1983 basic_block join_bb
= NULL_BLOCK
;
1984 edge then_succ
= then_bb
->succ
;
1985 edge else_succ
= else_bb
->succ
;
1988 /* The THEN block of an IF-THEN combo must have exactly one predecessor. */
1989 if (then_bb
->pred
->pred_next
!= NULL_EDGE
)
1992 /* The THEN block of an IF-THEN combo must have zero or one successors. */
1993 if (then_succ
!= NULL_EDGE
1994 && (then_succ
->succ_next
!= NULL_EDGE
1995 || (then_succ
->flags
& EDGE_COMPLEX
)))
1998 /* If the THEN block has no successors, conditional execution can still
1999 make a conditional call. Don't do this unless the ELSE block has
2000 only one incoming edge -- the CFG manipulation is too ugly otherwise.
2001 Check for the last insn of the THEN block being an indirect jump, which
2002 is listed as not having any successors, but confuses the rest of the CE
2003 code processing. XXX we should fix this in the future. */
2004 if (then_succ
== NULL
)
2006 if (else_bb
->pred
->pred_next
== NULL_EDGE
)
2008 rtx last_insn
= then_bb
->end
;
2011 && GET_CODE (last_insn
) == NOTE
2012 && last_insn
!= then_bb
->head
)
2013 last_insn
= PREV_INSN (last_insn
);
2016 && GET_CODE (last_insn
) == JUMP_INSN
2017 && ! simplejump_p (last_insn
))
2021 else_bb
= NULL_BLOCK
;
2027 /* If the THEN block's successor is the other edge out of the TEST block,
2028 then we have an IF-THEN combo without an ELSE. */
2029 else if (then_succ
->dest
== else_bb
)
2032 else_bb
= NULL_BLOCK
;
2035 /* If the THEN and ELSE block meet in a subsequent block, and the ELSE
2036 has exactly one predecessor and one successor, and the outgoing edge
2037 is not complex, then we have an IF-THEN-ELSE combo. */
2038 else if (else_succ
!= NULL_EDGE
2039 && then_succ
->dest
== else_succ
->dest
2040 && else_bb
->pred
->pred_next
== NULL_EDGE
2041 && else_succ
->succ_next
== NULL_EDGE
2042 && ! (else_succ
->flags
& EDGE_COMPLEX
))
2043 join_bb
= else_succ
->dest
;
2045 /* Otherwise it is not an IF-THEN or IF-THEN-ELSE combination. */
2049 num_possible_if_blocks
++;
2054 fprintf (rtl_dump_file
,
2055 "\nIF-THEN-ELSE block found, start %d, then %d, else %d, join %d\n",
2056 test_bb
->index
, then_bb
->index
, else_bb
->index
,
2059 fprintf (rtl_dump_file
,
2060 "\nIF-THEN block found, start %d, then %d, join %d\n",
2061 test_bb
->index
, then_bb
->index
, join_bb
->index
);
2064 /* Make sure IF, THEN, and ELSE, blocks are adjacent. Actually, we
2065 get the first condition for free, since we've already asserted that
2066 there's a fallthru edge from IF to THEN. */
2067 /* ??? As an enhancement, move the ELSE block. Have to deal with
2068 BLOCK notes, if by no other means than aborting the merge if they
2069 exist. Sticky enough I don't want to think about it now. */
2070 next_index
= then_bb
->index
;
2071 if (else_bb
&& ++next_index
!= else_bb
->index
)
2073 if (++next_index
!= join_bb
->index
&& join_bb
->index
!= EXIT_BLOCK
)
2081 /* Do the real work. */
2082 return process_if_block (test_bb
, then_bb
, else_bb
, join_bb
);
2085 /* Convert a branch over a trap, or a branch to a trap,
2086 into a conditional trap. */
2089 find_cond_trap (test_bb
, then_edge
, else_edge
)
2090 basic_block test_bb
;
2091 edge then_edge
, else_edge
;
2093 basic_block then_bb
, else_bb
, join_bb
, trap_bb
;
2094 rtx trap
, jump
, cond
, cond_earliest
, seq
;
2097 then_bb
= then_edge
->dest
;
2098 else_bb
= else_edge
->dest
;
2101 /* Locate the block with the trap instruction. */
2102 /* ??? While we look for no successors, we really ought to allow
2103 EH successors. Need to fix merge_if_block for that to work. */
2104 /* ??? We can't currently handle merging the blocks if they are not
2105 already adjacent. Prevent losage in merge_if_block by detecting
2107 if (then_bb
->succ
== NULL
)
2110 if (else_bb
->index
!= then_bb
->index
+ 1)
2115 else if (else_bb
->succ
== NULL
)
2118 if (else_bb
->index
!= then_bb
->index
+ 1)
2120 else if (then_bb
->succ
2121 && ! then_bb
->succ
->succ_next
2122 && ! (then_bb
->succ
->flags
& EDGE_COMPLEX
)
2123 && then_bb
->succ
->dest
->index
== else_bb
->index
+ 1)
2124 join_bb
= then_bb
->succ
->dest
;
2129 /* Don't confuse a conditional return with something we want to
2131 if (trap_bb
== EXIT_BLOCK_PTR
)
2134 /* The only instruction in the THEN block must be the trap. */
2135 trap
= first_active_insn (trap_bb
);
2136 if (! (trap
== trap_bb
->end
2137 && GET_CODE (PATTERN (trap
)) == TRAP_IF
2138 && TRAP_CONDITION (PATTERN (trap
)) == const_true_rtx
))
2143 if (trap_bb
== then_bb
)
2144 fprintf (rtl_dump_file
,
2145 "\nTRAP-IF block found, start %d, trap %d",
2146 test_bb
->index
, then_bb
->index
);
2148 fprintf (rtl_dump_file
,
2149 "\nTRAP-IF block found, start %d, then %d, trap %d",
2150 test_bb
->index
, then_bb
->index
, trap_bb
->index
);
2152 fprintf (rtl_dump_file
, ", join %d\n", join_bb
->index
);
2154 fputc ('\n', rtl_dump_file
);
2157 /* If this is not a standard conditional jump, we can't parse it. */
2158 jump
= test_bb
->end
;
2159 cond
= noce_get_condition (jump
, &cond_earliest
);
2163 /* If the conditional jump is more than just a conditional jump,
2164 then we can not do if-conversion on this block. */
2165 if (! onlyjump_p (jump
))
2168 /* We must be comparing objects whose modes imply the size. */
2169 if (GET_MODE (XEXP (cond
, 0)) == BLKmode
)
2172 /* Reverse the comparison code, if necessary. */
2173 code
= GET_CODE (cond
);
2174 if (then_bb
== trap_bb
)
2176 code
= reversed_comparison_code (cond
, jump
);
2177 if (code
== UNKNOWN
)
2181 /* Attempt to generate the conditional trap. */
2182 seq
= gen_cond_trap (code
, XEXP (cond
, 0), XEXP (cond
, 1),
2183 TRAP_CODE (PATTERN (trap
)));
2187 /* Emit the new insns before cond_earliest; delete the old jump
2190 emit_insn_before (seq
, cond_earliest
);
2196 /* Merge the blocks! */
2197 if (trap_bb
!= then_bb
&& ! else_bb
)
2199 flow_delete_block (trap_bb
);
2200 num_removed_blocks
++;
2202 merge_if_block (test_bb
, then_bb
, else_bb
, join_bb
);
2207 /* Look for IF-THEN-ELSE cases in which one of THEN or ELSE is
2208 transformable, but not necessarily the other. There need be no
2211 Return TRUE if we were successful at converting the the block.
2213 Cases we'd like to look at:
2216 if (test) goto over; // x not live
2224 if (! test) goto label;
2227 if (test) goto E; // x not live
2241 (3) // This one's really only interesting for targets that can do
2242 // multiway branching, e.g. IA-64 BBB bundles. For other targets
2243 // it results in multiple branches on a cache line, which often
2244 // does not sit well with predictors.
2246 if (test1) goto E; // predicted not taken
2262 (A) Don't do (2) if the branch is predicted against the block we're
2263 eliminating. Do it anyway if we can eliminate a branch; this requires
2264 that the sole successor of the eliminated block postdominate the other
2267 (B) With CE, on (3) we can steal from both sides of the if, creating
2276 Again, this is most useful if J postdominates.
2278 (C) CE substitutes for helpful life information.
2280 (D) These heuristics need a lot of work. */
2282 /* Tests for case 1 above. */
2285 find_if_case_1 (test_bb
, then_edge
, else_edge
)
2286 basic_block test_bb
;
2287 edge then_edge
, else_edge
;
2289 basic_block then_bb
= then_edge
->dest
;
2290 basic_block else_bb
= else_edge
->dest
, new_bb
;
2291 edge then_succ
= then_bb
->succ
;
2293 /* THEN has one successor. */
2294 if (!then_succ
|| then_succ
->succ_next
!= NULL
)
2297 /* THEN does not fall through, but is not strange either. */
2298 if (then_succ
->flags
& (EDGE_COMPLEX
| EDGE_FALLTHRU
))
2301 /* THEN has one predecessor. */
2302 if (then_bb
->pred
->pred_next
!= NULL
)
2305 /* THEN must do something. */
2306 if (forwarder_block_p (then_bb
))
2309 num_possible_if_blocks
++;
2311 fprintf (rtl_dump_file
,
2312 "\nIF-CASE-1 found, start %d, then %d\n",
2313 test_bb
->index
, then_bb
->index
);
2315 /* THEN is small. */
2316 if (count_bb_insns (then_bb
) > BRANCH_COST
)
2319 /* Registers set are dead, or are predicable. */
2320 if (! dead_or_predicable (test_bb
, then_bb
, else_bb
,
2321 then_bb
->succ
->dest
, 1))
2324 /* Conversion went ok, including moving the insns and fixing up the
2325 jump. Adjust the CFG to match. */
2327 SET_UPDATE_LIFE (test_bb
);
2328 bitmap_operation (test_bb
->global_live_at_end
,
2329 else_bb
->global_live_at_start
,
2330 then_bb
->global_live_at_end
, BITMAP_IOR
);
2332 new_bb
= redirect_edge_and_branch_force (FALLTHRU_EDGE (test_bb
), else_bb
);
2333 /* Make rest of code believe that the newly created block is the THEN_BB
2334 block we are going to remove. */
2337 new_bb
->aux
= then_bb
->aux
;
2338 SET_UPDATE_LIFE (then_bb
);
2340 flow_delete_block (then_bb
);
2341 /* We've possibly created jump to next insn, cleanup_cfg will solve that
2344 num_removed_blocks
++;
2345 num_updated_if_blocks
++;
2350 /* Test for case 2 above. */
2353 find_if_case_2 (test_bb
, then_edge
, else_edge
)
2354 basic_block test_bb
;
2355 edge then_edge
, else_edge
;
2357 basic_block then_bb
= then_edge
->dest
;
2358 basic_block else_bb
= else_edge
->dest
;
2359 edge else_succ
= else_bb
->succ
;
2362 /* ELSE has one successor. */
2363 if (!else_succ
|| else_succ
->succ_next
!= NULL
)
2366 /* ELSE outgoing edge is not complex. */
2367 if (else_succ
->flags
& EDGE_COMPLEX
)
2370 /* ELSE has one predecessor. */
2371 if (else_bb
->pred
->pred_next
!= NULL
)
2374 /* THEN is not EXIT. */
2375 if (then_bb
->index
< 0)
2378 /* ELSE is predicted or SUCC(ELSE) postdominates THEN. */
2379 note
= find_reg_note (test_bb
->end
, REG_BR_PROB
, NULL_RTX
);
2380 if (note
&& INTVAL (XEXP (note
, 0)) >= REG_BR_PROB_BASE
/ 2)
2382 else if (else_succ
->dest
->index
< 0
2383 || TEST_BIT (post_dominators
[ORIG_INDEX (then_bb
)],
2384 ORIG_INDEX (else_succ
->dest
)))
2389 num_possible_if_blocks
++;
2391 fprintf (rtl_dump_file
,
2392 "\nIF-CASE-2 found, start %d, else %d\n",
2393 test_bb
->index
, else_bb
->index
);
2395 /* ELSE is small. */
2396 if (count_bb_insns (then_bb
) > BRANCH_COST
)
2399 /* Registers set are dead, or are predicable. */
2400 if (! dead_or_predicable (test_bb
, else_bb
, then_bb
, else_succ
->dest
, 0))
2403 /* Conversion went ok, including moving the insns and fixing up the
2404 jump. Adjust the CFG to match. */
2406 SET_UPDATE_LIFE (test_bb
);
2407 bitmap_operation (test_bb
->global_live_at_end
,
2408 then_bb
->global_live_at_start
,
2409 else_bb
->global_live_at_end
, BITMAP_IOR
);
2411 flow_delete_block (else_bb
);
2413 num_removed_blocks
++;
2414 num_updated_if_blocks
++;
2416 /* ??? We may now fallthru from one of THEN's successors into a join
2417 block. Rerun cleanup_cfg? Examine things manually? Wait? */
2422 /* A subroutine of dead_or_predicable called through for_each_rtx.
2423 Return 1 if a memory is found. */
2426 find_memory (px
, data
)
2428 void *data ATTRIBUTE_UNUSED
;
2430 return GET_CODE (*px
) == MEM
;
2433 /* Used by the code above to perform the actual rtl transformations.
2434 Return TRUE if successful.
2436 TEST_BB is the block containing the conditional branch. MERGE_BB
2437 is the block containing the code to manipulate. NEW_DEST is the
2438 label TEST_BB should be branching to after the conversion.
2439 REVERSEP is true if the sense of the branch should be reversed. */
2442 dead_or_predicable (test_bb
, merge_bb
, other_bb
, new_dest
, reversep
)
2443 basic_block test_bb
, merge_bb
, other_bb
;
2444 basic_block new_dest
;
2447 rtx head
, end
, jump
, earliest
, old_dest
, new_label
;
2449 jump
= test_bb
->end
;
2451 /* Find the extent of the real code in the merge block. */
2452 head
= merge_bb
->head
;
2453 end
= merge_bb
->end
;
2455 if (GET_CODE (head
) == CODE_LABEL
)
2456 head
= NEXT_INSN (head
);
2457 if (GET_CODE (head
) == NOTE
)
2461 head
= end
= NULL_RTX
;
2464 head
= NEXT_INSN (head
);
2467 if (GET_CODE (end
) == JUMP_INSN
)
2471 head
= end
= NULL_RTX
;
2474 end
= PREV_INSN (end
);
2477 /* Disable handling dead code by conditional execution if the machine needs
2478 to do anything funny with the tests, etc. */
2479 #ifndef IFCVT_MODIFY_TESTS
2480 if (HAVE_conditional_execution
)
2482 /* In the conditional execution case, we have things easy. We know
2483 the condition is reversable. We don't have to check life info,
2484 becase we're going to conditionally execute the code anyway.
2485 All that's left is making sure the insns involved can actually
2490 cond
= cond_exec_get_condition (jump
);
2494 prob_val
= find_reg_note (jump
, REG_BR_PROB
, NULL_RTX
);
2496 prob_val
= XEXP (prob_val
, 0);
2500 enum rtx_code rev
= reversed_comparison_code (cond
, jump
);
2503 cond
= gen_rtx_fmt_ee (rev
, GET_MODE (cond
), XEXP (cond
, 0),
2506 prob_val
= GEN_INT (REG_BR_PROB_BASE
- INTVAL (prob_val
));
2509 if (! cond_exec_process_insns (head
, end
, cond
, prob_val
, 0))
2517 /* In the non-conditional execution case, we have to verify that there
2518 are no trapping operations, no calls, no references to memory, and
2519 that any registers modified are dead at the branch site. */
2521 rtx insn
, cond
, prev
;
2522 regset_head merge_set_head
, tmp_head
, test_live_head
, test_set_head
;
2523 regset merge_set
, tmp
, test_live
, test_set
;
2524 struct propagate_block_info
*pbi
;
2527 /* Check for no calls or trapping operations. */
2528 for (insn
= head
; ; insn
= NEXT_INSN (insn
))
2530 if (GET_CODE (insn
) == CALL_INSN
)
2534 if (may_trap_p (PATTERN (insn
)))
2537 /* ??? Even non-trapping memories such as stack frame
2538 references must be avoided. For stores, we collect
2539 no lifetime info; for reads, we'd have to assert
2540 true_dependence false against every store in the
2542 if (for_each_rtx (&PATTERN (insn
), find_memory
, NULL
))
2549 if (! any_condjump_p (jump
))
2552 /* Find the extent of the conditional. */
2553 cond
= noce_get_condition (jump
, &earliest
);
2558 MERGE_SET = set of registers set in MERGE_BB
2559 TEST_LIVE = set of registers live at EARLIEST
2560 TEST_SET = set of registers set between EARLIEST and the
2561 end of the block. */
2563 tmp
= INITIALIZE_REG_SET (tmp_head
);
2564 merge_set
= INITIALIZE_REG_SET (merge_set_head
);
2565 test_live
= INITIALIZE_REG_SET (test_live_head
);
2566 test_set
= INITIALIZE_REG_SET (test_set_head
);
2568 /* ??? bb->local_set is only valid during calculate_global_regs_live,
2569 so we must recompute usage for MERGE_BB. Not so bad, I suppose,
2570 since we've already asserted that MERGE_BB is small. */
2571 propagate_block (merge_bb
, tmp
, merge_set
, merge_set
, 0);
2573 /* For small register class machines, don't lengthen lifetimes of
2574 hard registers before reload. */
2575 if (SMALL_REGISTER_CLASSES
&& ! reload_completed
)
2577 EXECUTE_IF_SET_IN_BITMAP
2580 if (i
< FIRST_PSEUDO_REGISTER
2582 && ! global_regs
[i
])
2587 /* For TEST, we're interested in a range of insns, not a whole block.
2588 Moreover, we're interested in the insns live from OTHER_BB. */
2590 COPY_REG_SET (test_live
, other_bb
->global_live_at_start
);
2591 pbi
= init_propagate_block_info (test_bb
, test_live
, test_set
, test_set
,
2594 for (insn
= jump
; ; insn
= prev
)
2596 prev
= propagate_one_insn (pbi
, insn
);
2597 if (insn
== earliest
)
2601 free_propagate_block_info (pbi
);
2603 /* We can perform the transformation if
2604 MERGE_SET & (TEST_SET | TEST_LIVE)
2606 TEST_SET & merge_bb->global_live_at_start
2609 bitmap_operation (tmp
, test_set
, test_live
, BITMAP_IOR
);
2610 bitmap_operation (tmp
, tmp
, merge_set
, BITMAP_AND
);
2611 EXECUTE_IF_SET_IN_BITMAP(tmp
, 0, i
, fail
= 1);
2613 bitmap_operation (tmp
, test_set
, merge_bb
->global_live_at_start
,
2615 EXECUTE_IF_SET_IN_BITMAP(tmp
, 0, i
, fail
= 1);
2618 FREE_REG_SET (merge_set
);
2619 FREE_REG_SET (test_live
);
2620 FREE_REG_SET (test_set
);
2627 /* We don't want to use normal invert_jump or redirect_jump because
2628 we don't want to delete_insn called. Also, we want to do our own
2629 change group management. */
2631 old_dest
= JUMP_LABEL (jump
);
2632 new_label
= block_label (new_dest
);
2634 ? ! invert_jump_1 (jump
, new_label
)
2635 : ! redirect_jump_1 (jump
, new_label
))
2638 if (! apply_change_group ())
2642 LABEL_NUSES (old_dest
) -= 1;
2644 LABEL_NUSES (new_label
) += 1;
2645 JUMP_LABEL (jump
) = new_label
;
2648 invert_br_probabilities (jump
);
2650 redirect_edge_succ (BRANCH_EDGE (test_bb
), new_dest
);
2653 gcov_type count
, probability
;
2654 count
= BRANCH_EDGE (test_bb
)->count
;
2655 BRANCH_EDGE (test_bb
)->count
= FALLTHRU_EDGE (test_bb
)->count
;
2656 FALLTHRU_EDGE (test_bb
)->count
= count
;
2657 probability
= BRANCH_EDGE (test_bb
)->probability
;
2658 BRANCH_EDGE (test_bb
)->probability
= FALLTHRU_EDGE (test_bb
)->probability
;
2659 FALLTHRU_EDGE (test_bb
)->probability
= probability
;
2662 /* Move the insns out of MERGE_BB to before the branch. */
2665 if (end
== merge_bb
->end
)
2666 merge_bb
->end
= PREV_INSN (head
);
2668 if (squeeze_notes (&head
, &end
))
2671 reorder_insns (head
, end
, PREV_INSN (earliest
));
2680 /* Main entry point for all if-conversion. */
2683 if_convert (x_life_data_ok
)
2688 num_possible_if_blocks
= 0;
2689 num_updated_if_blocks
= 0;
2690 num_removed_blocks
= 0;
2691 life_data_ok
= (x_life_data_ok
!= 0);
2693 /* Free up basic_block_for_insn so that we don't have to keep it
2694 up to date, either here or in merge_blocks_nomove. */
2695 free_basic_block_vars (1);
2697 /* Compute postdominators if we think we'll use them. */
2698 post_dominators
= NULL
;
2699 if (HAVE_conditional_execution
|| life_data_ok
)
2701 post_dominators
= sbitmap_vector_alloc (n_basic_blocks
, n_basic_blocks
);
2702 calculate_dominance_info (NULL
, post_dominators
, CDI_POST_DOMINATORS
);
2705 /* Record initial block numbers. */
2706 for (block_num
= 0; block_num
< n_basic_blocks
; block_num
++)
2707 SET_ORIG_INDEX (BASIC_BLOCK (block_num
), block_num
);
2709 /* Go through each of the basic blocks looking for things to convert. */
2710 for (block_num
= 0; block_num
< n_basic_blocks
; )
2712 basic_block bb
= BASIC_BLOCK (block_num
);
2713 if (find_if_header (bb
))
2714 block_num
= bb
->index
;
2719 if (post_dominators
)
2720 sbitmap_vector_free (post_dominators
);
2723 fflush (rtl_dump_file
);
2725 /* Rebuild life info for basic blocks that require it. */
2726 if (num_removed_blocks
&& life_data_ok
)
2728 sbitmap update_life_blocks
= sbitmap_alloc (n_basic_blocks
);
2729 sbitmap_zero (update_life_blocks
);
2731 /* If we allocated new pseudos, we must resize the array for sched1. */
2732 if (max_regno
< max_reg_num ())
2734 max_regno
= max_reg_num ();
2735 allocate_reg_info (max_regno
, FALSE
, FALSE
);
2738 for (block_num
= 0; block_num
< n_basic_blocks
; block_num
++)
2739 if (UPDATE_LIFE (BASIC_BLOCK (block_num
)))
2740 SET_BIT (update_life_blocks
, block_num
);
2742 count_or_remove_death_notes (update_life_blocks
, 1);
2743 /* ??? See about adding a mode that verifies that the initial
2744 set of blocks don't let registers come live. */
2745 update_life_info (update_life_blocks
, UPDATE_LIFE_GLOBAL
,
2746 PROP_DEATH_NOTES
| PROP_SCAN_DEAD_CODE
2747 | PROP_KILL_DEAD_CODE
);
2749 sbitmap_free (update_life_blocks
);
2751 clear_aux_for_blocks ();
2753 /* Write the final stats. */
2754 if (rtl_dump_file
&& num_possible_if_blocks
> 0)
2756 fprintf (rtl_dump_file
,
2757 "\n%d possible IF blocks searched.\n",
2758 num_possible_if_blocks
);
2759 fprintf (rtl_dump_file
,
2760 "%d IF blocks converted.\n",
2761 num_updated_if_blocks
);
2762 fprintf (rtl_dump_file
,
2763 "%d basic blocks deleted.\n\n\n",
2764 num_removed_blocks
);
2767 #ifdef ENABLE_CHECKING
2768 verify_flow_info ();