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
);
653 diff
= trunc_int_for_mode (itrue
- ifalse
, mode
);
655 can_reverse
= (reversed_comparison_code (if_info
->cond
, if_info
->jump
)
659 if (diff
== STORE_FLAG_VALUE
|| diff
== -STORE_FLAG_VALUE
)
661 else if (ifalse
== 0 && exact_log2 (itrue
) >= 0
662 && (STORE_FLAG_VALUE
== 1
663 || BRANCH_COST
>= 2))
665 else if (itrue
== 0 && exact_log2 (ifalse
) >= 0 && can_reverse
666 && (STORE_FLAG_VALUE
== 1 || BRANCH_COST
>= 2))
667 normalize
= 1, reversep
= 1;
669 && (STORE_FLAG_VALUE
== -1
670 || BRANCH_COST
>= 2))
672 else if (ifalse
== -1 && can_reverse
673 && (STORE_FLAG_VALUE
== -1 || BRANCH_COST
>= 2))
674 normalize
= -1, reversep
= 1;
675 else if ((BRANCH_COST
>= 2 && STORE_FLAG_VALUE
== -1)
683 tmp
= itrue
; itrue
= ifalse
; ifalse
= tmp
;
684 diff
= trunc_int_for_mode (-diff
, mode
);
688 target
= noce_emit_store_flag (if_info
, if_info
->x
, reversep
, normalize
);
695 /* if (test) x = 3; else x = 4;
696 => x = 3 + (test == 0); */
697 if (diff
== STORE_FLAG_VALUE
|| diff
== -STORE_FLAG_VALUE
)
699 target
= expand_simple_binop (mode
,
700 (diff
== STORE_FLAG_VALUE
702 GEN_INT (ifalse
), target
, if_info
->x
, 0,
706 /* if (test) x = 8; else x = 0;
707 => x = (test != 0) << 3; */
708 else if (ifalse
== 0 && (tmp
= exact_log2 (itrue
)) >= 0)
710 target
= expand_simple_binop (mode
, ASHIFT
,
711 target
, GEN_INT (tmp
), if_info
->x
, 0,
715 /* if (test) x = -1; else x = b;
716 => x = -(test != 0) | b; */
717 else if (itrue
== -1)
719 target
= expand_simple_binop (mode
, IOR
,
720 target
, GEN_INT (ifalse
), if_info
->x
, 0,
724 /* if (test) x = a; else x = b;
725 => x = (-(test != 0) & (b - a)) + a; */
728 target
= expand_simple_binop (mode
, AND
,
729 target
, GEN_INT (diff
), if_info
->x
, 0,
732 target
= expand_simple_binop (mode
, PLUS
,
733 target
, GEN_INT (ifalse
),
734 if_info
->x
, 0, OPTAB_WIDEN
);
743 if (target
!= if_info
->x
)
744 noce_emit_move_insn (if_info
->x
, target
);
749 if (seq_contains_jump (seq
))
752 emit_insns_before (seq
, if_info
->cond_earliest
);
760 /* Convert "if (test) foo++" into "foo += (test != 0)", and
761 similarly for "foo--". */
764 noce_try_store_flag_inc (if_info
)
765 struct noce_if_info
*if_info
;
768 int subtract
, normalize
;
774 /* Should be no `else' case to worry about. */
775 && if_info
->b
== if_info
->x
776 && GET_CODE (if_info
->a
) == PLUS
777 && (XEXP (if_info
->a
, 1) == const1_rtx
778 || XEXP (if_info
->a
, 1) == constm1_rtx
)
779 && rtx_equal_p (XEXP (if_info
->a
, 0), if_info
->x
)
780 && (reversed_comparison_code (if_info
->cond
, if_info
->jump
)
783 if (STORE_FLAG_VALUE
== INTVAL (XEXP (if_info
->a
, 1)))
784 subtract
= 0, normalize
= 0;
785 else if (-STORE_FLAG_VALUE
== INTVAL (XEXP (if_info
->a
, 1)))
786 subtract
= 1, normalize
= 0;
788 subtract
= 0, normalize
= INTVAL (XEXP (if_info
->a
, 1));
792 target
= noce_emit_store_flag (if_info
,
793 gen_reg_rtx (GET_MODE (if_info
->x
)),
797 target
= expand_simple_binop (GET_MODE (if_info
->x
),
798 subtract
? MINUS
: PLUS
,
799 if_info
->x
, target
, if_info
->x
,
803 if (target
!= if_info
->x
)
804 noce_emit_move_insn (if_info
->x
, target
);
809 if (seq_contains_jump (seq
))
812 emit_insns_before (seq
, if_info
->cond_earliest
);
823 /* Convert "if (test) x = 0;" to "x &= -(test == 0);" */
826 noce_try_store_flag_mask (if_info
)
827 struct noce_if_info
*if_info
;
835 || STORE_FLAG_VALUE
== -1)
836 && ((if_info
->a
== const0_rtx
837 && rtx_equal_p (if_info
->b
, if_info
->x
))
838 || ((reversep
= (reversed_comparison_code (if_info
->cond
,
841 && if_info
->b
== const0_rtx
842 && rtx_equal_p (if_info
->a
, if_info
->x
))))
845 target
= noce_emit_store_flag (if_info
,
846 gen_reg_rtx (GET_MODE (if_info
->x
)),
849 target
= expand_simple_binop (GET_MODE (if_info
->x
), AND
,
850 if_info
->x
, target
, if_info
->x
, 0,
855 if (target
!= if_info
->x
)
856 noce_emit_move_insn (if_info
->x
, target
);
861 if (seq_contains_jump (seq
))
864 emit_insns_before (seq
, if_info
->cond_earliest
);
875 /* Helper function for noce_try_cmove and noce_try_cmove_arith. */
878 noce_emit_cmove (if_info
, x
, code
, cmp_a
, cmp_b
, vfalse
, vtrue
)
879 struct noce_if_info
*if_info
;
880 rtx x
, cmp_a
, cmp_b
, vfalse
, vtrue
;
883 /* If earliest == jump, try to build the cmove insn directly.
884 This is helpful when combine has created some complex condition
885 (like for alpha's cmovlbs) that we can't hope to regenerate
886 through the normal interface. */
888 if (if_info
->cond_earliest
== if_info
->jump
)
892 tmp
= gen_rtx_fmt_ee (code
, GET_MODE (if_info
->cond
), cmp_a
, cmp_b
);
893 tmp
= gen_rtx_IF_THEN_ELSE (GET_MODE (x
), tmp
, vtrue
, vfalse
);
894 tmp
= gen_rtx_SET (VOIDmode
, x
, tmp
);
897 tmp
= emit_insn (tmp
);
899 if (recog_memoized (tmp
) >= 0)
911 /* Don't even try if the comparison operands are weird. */
912 if (! general_operand (cmp_a
, GET_MODE (cmp_a
))
913 || ! general_operand (cmp_b
, GET_MODE (cmp_b
)))
916 #if HAVE_conditional_move
917 return emit_conditional_move (x
, code
, cmp_a
, cmp_b
, VOIDmode
,
918 vtrue
, vfalse
, GET_MODE (x
),
919 (code
== LTU
|| code
== GEU
920 || code
== LEU
|| code
== GTU
));
922 /* We'll never get here, as noce_process_if_block doesn't call the
923 functions involved. Ifdef code, however, should be discouraged
924 because it leads to typos in the code not selected. However,
925 emit_conditional_move won't exist either. */
930 /* Try only simple constants and registers here. More complex cases
931 are handled in noce_try_cmove_arith after noce_try_store_flag_arith
932 has had a go at it. */
935 noce_try_cmove (if_info
)
936 struct noce_if_info
*if_info
;
941 if ((CONSTANT_P (if_info
->a
) || register_operand (if_info
->a
, VOIDmode
))
942 && (CONSTANT_P (if_info
->b
) || register_operand (if_info
->b
, VOIDmode
)))
946 code
= GET_CODE (if_info
->cond
);
947 target
= noce_emit_cmove (if_info
, if_info
->x
, code
,
948 XEXP (if_info
->cond
, 0),
949 XEXP (if_info
->cond
, 1),
950 if_info
->a
, if_info
->b
);
954 if (target
!= if_info
->x
)
955 noce_emit_move_insn (if_info
->x
, target
);
959 emit_insns_before (seq
, if_info
->cond_earliest
);
972 /* Try more complex cases involving conditional_move. */
975 noce_try_cmove_arith (if_info
)
976 struct noce_if_info
*if_info
;
986 /* A conditional move from two memory sources is equivalent to a
987 conditional on their addresses followed by a load. Don't do this
988 early because it'll screw alias analysis. Note that we've
989 already checked for no side effects. */
990 if (! no_new_pseudos
&& cse_not_expected
991 && GET_CODE (a
) == MEM
&& GET_CODE (b
) == MEM
996 x
= gen_reg_rtx (Pmode
);
1000 /* ??? We could handle this if we knew that a load from A or B could
1001 not fault. This is also true if we've already loaded
1002 from the address along the path from ENTRY. */
1003 else if (may_trap_p (a
) || may_trap_p (b
))
1006 /* if (test) x = a + b; else x = c - d;
1013 code
= GET_CODE (if_info
->cond
);
1014 insn_a
= if_info
->insn_a
;
1015 insn_b
= if_info
->insn_b
;
1017 /* Possibly rearrange operands to make things come out more natural. */
1018 if (reversed_comparison_code (if_info
->cond
, if_info
->jump
) != UNKNOWN
)
1021 if (rtx_equal_p (b
, x
))
1023 else if (general_operand (b
, GET_MODE (b
)))
1028 code
= reversed_comparison_code (if_info
->cond
, if_info
->jump
);
1029 tmp
= a
, a
= b
, b
= tmp
;
1030 tmp
= insn_a
, insn_a
= insn_b
, insn_b
= tmp
;
1036 /* If either operand is complex, load it into a register first.
1037 The best way to do this is to copy the original insn. In this
1038 way we preserve any clobbers etc that the insn may have had.
1039 This is of course not possible in the IS_MEM case. */
1040 if (! general_operand (a
, GET_MODE (a
)))
1045 goto end_seq_and_fail
;
1049 tmp
= gen_reg_rtx (GET_MODE (a
));
1050 tmp
= emit_insn (gen_rtx_SET (VOIDmode
, tmp
, a
));
1053 goto end_seq_and_fail
;
1056 a
= gen_reg_rtx (GET_MODE (a
));
1057 tmp
= copy_rtx (insn_a
);
1058 set
= single_set (tmp
);
1060 tmp
= emit_insn (PATTERN (tmp
));
1062 if (recog_memoized (tmp
) < 0)
1063 goto end_seq_and_fail
;
1065 if (! general_operand (b
, GET_MODE (b
)))
1070 goto end_seq_and_fail
;
1074 tmp
= gen_reg_rtx (GET_MODE (b
));
1075 tmp
= emit_insn (gen_rtx_SET (VOIDmode
, tmp
, b
));
1078 goto end_seq_and_fail
;
1081 b
= gen_reg_rtx (GET_MODE (b
));
1082 tmp
= copy_rtx (insn_b
);
1083 set
= single_set (tmp
);
1085 tmp
= emit_insn (PATTERN (tmp
));
1087 if (recog_memoized (tmp
) < 0)
1088 goto end_seq_and_fail
;
1091 target
= noce_emit_cmove (if_info
, x
, code
, XEXP (if_info
->cond
, 0),
1092 XEXP (if_info
->cond
, 1), a
, b
);
1095 goto end_seq_and_fail
;
1097 /* If we're handling a memory for above, emit the load now. */
1100 tmp
= gen_rtx_MEM (GET_MODE (if_info
->x
), target
);
1102 /* Copy over flags as appropriate. */
1103 if (MEM_VOLATILE_P (if_info
->a
) || MEM_VOLATILE_P (if_info
->b
))
1104 MEM_VOLATILE_P (tmp
) = 1;
1105 if (MEM_IN_STRUCT_P (if_info
->a
) && MEM_IN_STRUCT_P (if_info
->b
))
1106 MEM_IN_STRUCT_P (tmp
) = 1;
1107 if (MEM_SCALAR_P (if_info
->a
) && MEM_SCALAR_P (if_info
->b
))
1108 MEM_SCALAR_P (tmp
) = 1;
1109 if (MEM_ALIAS_SET (if_info
->a
) == MEM_ALIAS_SET (if_info
->b
))
1110 set_mem_alias_set (tmp
, MEM_ALIAS_SET (if_info
->a
));
1112 MIN (MEM_ALIGN (if_info
->a
), MEM_ALIGN (if_info
->b
)));
1114 noce_emit_move_insn (if_info
->x
, tmp
);
1116 else if (target
!= x
)
1117 noce_emit_move_insn (x
, target
);
1121 emit_insns_before (tmp
, if_info
->cond_earliest
);
1129 /* For most cases, the simplified condition we found is the best
1130 choice, but this is not the case for the min/max/abs transforms.
1131 For these we wish to know that it is A or B in the condition. */
1134 noce_get_alt_condition (if_info
, target
, earliest
)
1135 struct noce_if_info
*if_info
;
1139 rtx cond
, set
, insn
;
1142 /* If target is already mentioned in the known condition, return it. */
1143 if (reg_mentioned_p (target
, if_info
->cond
))
1145 *earliest
= if_info
->cond_earliest
;
1146 return if_info
->cond
;
1149 set
= pc_set (if_info
->jump
);
1150 cond
= XEXP (SET_SRC (set
), 0);
1152 = GET_CODE (XEXP (SET_SRC (set
), 2)) == LABEL_REF
1153 && XEXP (XEXP (SET_SRC (set
), 2), 0) == JUMP_LABEL (if_info
->jump
);
1155 /* If we're looking for a constant, try to make the conditional
1156 have that constant in it. There are two reasons why it may
1157 not have the constant we want:
1159 1. GCC may have needed to put the constant in a register, because
1160 the target can't compare directly against that constant. For
1161 this case, we look for a SET immediately before the comparison
1162 that puts a constant in that register.
1164 2. GCC may have canonicalized the conditional, for example
1165 replacing "if x < 4" with "if x <= 3". We can undo that (or
1166 make equivalent types of changes) to get the constants we need
1167 if they're off by one in the right direction. */
1169 if (GET_CODE (target
) == CONST_INT
)
1171 enum rtx_code code
= GET_CODE (if_info
->cond
);
1172 rtx op_a
= XEXP (if_info
->cond
, 0);
1173 rtx op_b
= XEXP (if_info
->cond
, 1);
1176 /* First, look to see if we put a constant in a register. */
1177 prev_insn
= PREV_INSN (if_info
->cond_earliest
);
1179 && INSN_P (prev_insn
)
1180 && GET_CODE (PATTERN (prev_insn
)) == SET
)
1182 rtx src
= find_reg_equal_equiv_note (prev_insn
);
1184 src
= SET_SRC (PATTERN (prev_insn
));
1185 if (GET_CODE (src
) == CONST_INT
)
1187 if (rtx_equal_p (op_a
, SET_DEST (PATTERN (prev_insn
))))
1189 else if (rtx_equal_p (op_b
, SET_DEST (PATTERN (prev_insn
))))
1192 if (GET_CODE (op_a
) == CONST_INT
)
1197 code
= swap_condition (code
);
1202 /* Now, look to see if we can get the right constant by
1203 adjusting the conditional. */
1204 if (GET_CODE (op_b
) == CONST_INT
)
1206 HOST_WIDE_INT desired_val
= INTVAL (target
);
1207 HOST_WIDE_INT actual_val
= INTVAL (op_b
);
1212 if (actual_val
== desired_val
+ 1)
1215 op_b
= GEN_INT (desired_val
);
1219 if (actual_val
== desired_val
- 1)
1222 op_b
= GEN_INT (desired_val
);
1226 if (actual_val
== desired_val
- 1)
1229 op_b
= GEN_INT (desired_val
);
1233 if (actual_val
== desired_val
+ 1)
1236 op_b
= GEN_INT (desired_val
);
1244 /* If we made any changes, generate a new conditional that is
1245 equivalent to what we started with, but has the right
1247 if (code
!= GET_CODE (if_info
->cond
)
1248 || op_a
!= XEXP (if_info
->cond
, 0)
1249 || op_b
!= XEXP (if_info
->cond
, 1))
1251 cond
= gen_rtx_fmt_ee (code
, GET_MODE (cond
), op_a
, op_b
);
1252 *earliest
= if_info
->cond_earliest
;
1257 cond
= canonicalize_condition (if_info
->jump
, cond
, reverse
,
1259 if (! cond
|| ! reg_mentioned_p (target
, cond
))
1262 /* We almost certainly searched back to a different place.
1263 Need to re-verify correct lifetimes. */
1265 /* X may not be mentioned in the range (cond_earliest, jump]. */
1266 for (insn
= if_info
->jump
; insn
!= *earliest
; insn
= PREV_INSN (insn
))
1267 if (INSN_P (insn
) && reg_mentioned_p (if_info
->x
, insn
))
1270 /* A and B may not be modified in the range [cond_earliest, jump). */
1271 for (insn
= *earliest
; insn
!= if_info
->jump
; insn
= NEXT_INSN (insn
))
1273 && (modified_in_p (if_info
->a
, insn
)
1274 || modified_in_p (if_info
->b
, insn
)))
1280 /* Convert "if (a < b) x = a; else x = b;" to "x = min(a, b);", etc. */
1283 noce_try_minmax (if_info
)
1284 struct noce_if_info
*if_info
;
1286 rtx cond
, earliest
, target
, seq
;
1287 enum rtx_code code
, op
;
1290 /* ??? Can't guarantee that expand_binop won't create pseudos. */
1294 /* ??? Reject FP modes since we don't know how 0 vs -0 or NaNs
1295 will be resolved with an SMIN/SMAX. It wouldn't be too hard
1296 to get the target to tell us... */
1297 if (FLOAT_MODE_P (GET_MODE (if_info
->x
))
1298 && TARGET_FLOAT_FORMAT
== IEEE_FLOAT_FORMAT
1299 && ! flag_unsafe_math_optimizations
)
1302 cond
= noce_get_alt_condition (if_info
, if_info
->a
, &earliest
);
1306 /* Verify the condition is of the form we expect, and canonicalize
1307 the comparison code. */
1308 code
= GET_CODE (cond
);
1309 if (rtx_equal_p (XEXP (cond
, 0), if_info
->a
))
1311 if (! rtx_equal_p (XEXP (cond
, 1), if_info
->b
))
1314 else if (rtx_equal_p (XEXP (cond
, 1), if_info
->a
))
1316 if (! rtx_equal_p (XEXP (cond
, 0), if_info
->b
))
1318 code
= swap_condition (code
);
1323 /* Determine what sort of operation this is. Note that the code is for
1324 a taken branch, so the code->operation mapping appears backwards. */
1357 target
= expand_simple_binop (GET_MODE (if_info
->x
), op
,
1358 if_info
->a
, if_info
->b
,
1359 if_info
->x
, unsignedp
, OPTAB_WIDEN
);
1365 if (target
!= if_info
->x
)
1366 noce_emit_move_insn (if_info
->x
, target
);
1371 if (seq_contains_jump (seq
))
1374 emit_insns_before (seq
, earliest
);
1375 if_info
->cond
= cond
;
1376 if_info
->cond_earliest
= earliest
;
1381 /* Convert "if (a < 0) x = -a; else x = a;" to "x = abs(a);", etc. */
1384 noce_try_abs (if_info
)
1385 struct noce_if_info
*if_info
;
1387 rtx cond
, earliest
, target
, seq
, a
, b
, c
;
1390 /* ??? Can't guarantee that expand_binop won't create pseudos. */
1394 /* Recognize A and B as constituting an ABS or NABS. */
1397 if (GET_CODE (a
) == NEG
&& rtx_equal_p (XEXP (a
, 0), b
))
1399 else if (GET_CODE (b
) == NEG
&& rtx_equal_p (XEXP (b
, 0), a
))
1401 c
= a
; a
= b
; b
= c
;
1407 cond
= noce_get_alt_condition (if_info
, b
, &earliest
);
1411 /* Verify the condition is of the form we expect. */
1412 if (rtx_equal_p (XEXP (cond
, 0), b
))
1414 else if (rtx_equal_p (XEXP (cond
, 1), b
))
1419 /* Verify that C is zero. Search backward through the block for
1420 a REG_EQUAL note if necessary. */
1423 rtx insn
, note
= NULL
;
1424 for (insn
= earliest
;
1425 insn
!= if_info
->test_bb
->head
;
1426 insn
= PREV_INSN (insn
))
1428 && ((note
= find_reg_note (insn
, REG_EQUAL
, c
))
1429 || (note
= find_reg_note (insn
, REG_EQUIV
, c
))))
1435 if (GET_CODE (c
) == MEM
1436 && GET_CODE (XEXP (c
, 0)) == SYMBOL_REF
1437 && CONSTANT_POOL_ADDRESS_P (XEXP (c
, 0)))
1438 c
= get_pool_constant (XEXP (c
, 0));
1440 /* Work around funny ideas get_condition has wrt canonicalization.
1441 Note that these rtx constants are known to be CONST_INT, and
1442 therefore imply integer comparisons. */
1443 if (c
== constm1_rtx
&& GET_CODE (cond
) == GT
)
1445 else if (c
== const1_rtx
&& GET_CODE (cond
) == LT
)
1447 else if (c
!= CONST0_RTX (GET_MODE (b
)))
1450 /* Determine what sort of operation this is. */
1451 switch (GET_CODE (cond
))
1470 target
= expand_simple_unop (GET_MODE (if_info
->x
), ABS
, b
, if_info
->x
, 0);
1472 /* ??? It's a quandry whether cmove would be better here, especially
1473 for integers. Perhaps combine will clean things up. */
1474 if (target
&& negate
)
1475 target
= expand_simple_unop (GET_MODE (target
), NEG
, target
, if_info
->x
, 0);
1483 if (target
!= if_info
->x
)
1484 noce_emit_move_insn (if_info
->x
, target
);
1489 if (seq_contains_jump (seq
))
1492 emit_insns_before (seq
, earliest
);
1493 if_info
->cond
= cond
;
1494 if_info
->cond_earliest
= earliest
;
1499 /* Look for the condition for the jump first. We'd prefer to avoid
1500 get_condition if we can -- it tries to look back for the contents
1501 of an original compare. On targets that use normal integers for
1502 comparisons, e.g. alpha, this is wasteful. */
1505 noce_get_condition (jump
, earliest
)
1512 /* If the condition variable is a register and is MODE_INT, accept it.
1513 Otherwise, fall back on get_condition. */
1515 if (! any_condjump_p (jump
))
1518 set
= pc_set (jump
);
1520 cond
= XEXP (SET_SRC (set
), 0);
1521 if (GET_CODE (XEXP (cond
, 0)) == REG
1522 && GET_MODE_CLASS (GET_MODE (XEXP (cond
, 0))) == MODE_INT
)
1526 /* If this branches to JUMP_LABEL when the condition is false,
1527 reverse the condition. */
1528 if (GET_CODE (XEXP (SET_SRC (set
), 2)) == LABEL_REF
1529 && XEXP (XEXP (SET_SRC (set
), 2), 0) == JUMP_LABEL (jump
))
1530 cond
= gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond
)),
1531 GET_MODE (cond
), XEXP (cond
, 0),
1535 cond
= get_condition (jump
, earliest
);
1540 /* Return true if OP is ok for if-then-else processing. */
1543 noce_operand_ok (op
)
1546 /* We special-case memories, so handle any of them with
1547 no address side effects. */
1548 if (GET_CODE (op
) == MEM
)
1549 return ! side_effects_p (XEXP (op
, 0));
1551 if (side_effects_p (op
))
1554 /* ??? Unfortuantely may_trap_p can't look at flag_trapping_math, due to
1555 being linked into the genfoo programs. This is probably a mistake.
1556 With finite operands, most fp operations don't trap. */
1557 if (!flag_trapping_math
&& FLOAT_MODE_P (GET_MODE (op
)))
1558 switch (GET_CODE (op
))
1564 /* ??? This is kinda lame -- almost every target will have forced
1565 the constant into a register first. But given the expense of
1566 division, this is probably for the best. */
1567 return (CONSTANT_P (XEXP (op
, 1))
1568 && XEXP (op
, 1) != CONST0_RTX (GET_MODE (op
))
1569 && ! may_trap_p (XEXP (op
, 0)));
1572 switch (GET_RTX_CLASS (GET_CODE (op
)))
1575 return ! may_trap_p (XEXP (op
, 0));
1578 return ! may_trap_p (XEXP (op
, 0)) && ! may_trap_p (XEXP (op
, 1));
1583 return ! may_trap_p (op
);
1586 /* Given a simple IF-THEN or IF-THEN-ELSE block, attempt to convert it
1587 without using conditional execution. Return TRUE if we were
1588 successful at converting the the block. */
1591 noce_process_if_block (test_bb
, then_bb
, else_bb
, join_bb
)
1592 basic_block test_bb
; /* Basic block test is in */
1593 basic_block then_bb
; /* Basic block for THEN block */
1594 basic_block else_bb
; /* Basic block for ELSE block */
1595 basic_block join_bb
; /* Basic block the join label is in */
1597 /* We're looking for patterns of the form
1599 (1) if (...) x = a; else x = b;
1600 (2) x = b; if (...) x = a;
1601 (3) if (...) x = a; // as if with an initial x = x.
1603 The later patterns require jumps to be more expensive.
1605 ??? For future expansion, look for multiple X in such patterns. */
1607 struct noce_if_info if_info
;
1610 rtx orig_x
, x
, a
, b
;
1611 rtx jump
, cond
, insn
;
1613 /* If this is not a standard conditional jump, we can't parse it. */
1614 jump
= test_bb
->end
;
1615 cond
= noce_get_condition (jump
, &if_info
.cond_earliest
);
1619 /* If the conditional jump is more than just a conditional jump,
1620 then we can not do if-conversion on this block. */
1621 if (! onlyjump_p (jump
))
1624 /* We must be comparing objects whose modes imply the size. */
1625 if (GET_MODE (XEXP (cond
, 0)) == BLKmode
)
1628 /* Look for one of the potential sets. */
1629 insn_a
= first_active_insn (then_bb
);
1631 || ! last_active_insn_p (then_bb
, insn_a
)
1632 || (set_a
= single_set (insn_a
)) == NULL_RTX
)
1635 x
= SET_DEST (set_a
);
1636 a
= SET_SRC (set_a
);
1638 /* Look for the other potential set. Make sure we've got equivalent
1640 /* ??? This is overconservative. Storing to two different mems is
1641 as easy as conditionally computing the address. Storing to a
1642 single mem merely requires a scratch memory to use as one of the
1643 destination addresses; often the memory immediately below the
1644 stack pointer is available for this. */
1648 insn_b
= first_active_insn (else_bb
);
1650 || ! last_active_insn_p (else_bb
, insn_b
)
1651 || (set_b
= single_set (insn_b
)) == NULL_RTX
1652 || ! rtx_equal_p (x
, SET_DEST (set_b
)))
1657 insn_b
= prev_nonnote_insn (if_info
.cond_earliest
);
1659 || GET_CODE (insn_b
) != INSN
1660 || (set_b
= single_set (insn_b
)) == NULL_RTX
1661 || ! rtx_equal_p (x
, SET_DEST (set_b
))
1662 || reg_mentioned_p (x
, cond
)
1663 || reg_mentioned_p (x
, a
)
1664 || reg_mentioned_p (x
, SET_SRC (set_b
)))
1665 insn_b
= set_b
= NULL_RTX
;
1667 b
= (set_b
? SET_SRC (set_b
) : x
);
1669 /* X may not be mentioned in the range (cond_earliest, jump]. */
1670 for (insn
= jump
; insn
!= if_info
.cond_earliest
; insn
= PREV_INSN (insn
))
1671 if (INSN_P (insn
) && reg_mentioned_p (x
, insn
))
1674 /* A and B may not be modified in the range [cond_earliest, jump). */
1675 for (insn
= if_info
.cond_earliest
; insn
!= jump
; insn
= NEXT_INSN (insn
))
1677 && (modified_in_p (a
, insn
) || modified_in_p (b
, insn
)))
1680 /* Only operate on register destinations, and even then avoid extending
1681 the lifetime of hard registers on small register class machines. */
1683 if (GET_CODE (x
) != REG
1684 || (SMALL_REGISTER_CLASSES
1685 && REGNO (x
) < FIRST_PSEUDO_REGISTER
))
1689 x
= gen_reg_rtx (GET_MODE (GET_CODE (x
) == STRICT_LOW_PART
1690 ? XEXP (x
, 0) : x
));
1693 /* Don't operate on sources that may trap or are volatile. */
1694 if (! noce_operand_ok (a
) || ! noce_operand_ok (b
))
1697 /* Set up the info block for our subroutines. */
1698 if_info
.test_bb
= test_bb
;
1699 if_info
.cond
= cond
;
1700 if_info
.jump
= jump
;
1701 if_info
.insn_a
= insn_a
;
1702 if_info
.insn_b
= insn_b
;
1707 /* Try optimizations in some approximation of a useful order. */
1708 /* ??? Should first look to see if X is live incoming at all. If it
1709 isn't, we don't need anything but an unconditional set. */
1711 /* Look and see if A and B are really the same. Avoid creating silly
1712 cmove constructs that no one will fix up later. */
1713 if (rtx_equal_p (a
, b
))
1715 /* If we have an INSN_B, we don't have to create any new rtl. Just
1716 move the instruction that we already have. If we don't have an
1717 INSN_B, that means that A == X, and we've got a noop move. In
1718 that case don't do anything and let the code below delete INSN_A. */
1719 if (insn_b
&& else_bb
)
1723 if (else_bb
&& insn_b
== else_bb
->end
)
1724 else_bb
->end
= PREV_INSN (insn_b
);
1725 reorder_insns (insn_b
, insn_b
, PREV_INSN (if_info
.cond_earliest
));
1727 /* If there was a REG_EQUAL note, delete it since it may have been
1728 true due to this insn being after a jump. */
1729 if ((note
= find_reg_note (insn_b
, REG_EQUAL
, NULL_RTX
)) != 0)
1730 remove_note (insn_b
, note
);
1734 /* If we have "x = b; if (...) x = a;", and x has side-effects, then
1735 x must be executed twice. */
1736 else if (insn_b
&& side_effects_p (orig_x
))
1743 if (noce_try_store_flag (&if_info
))
1745 if (noce_try_minmax (&if_info
))
1747 if (noce_try_abs (&if_info
))
1749 if (HAVE_conditional_move
1750 && noce_try_cmove (&if_info
))
1752 if (! HAVE_conditional_execution
)
1754 if (noce_try_store_flag_constants (&if_info
))
1756 if (noce_try_store_flag_inc (&if_info
))
1758 if (noce_try_store_flag_mask (&if_info
))
1760 if (HAVE_conditional_move
1761 && noce_try_cmove_arith (&if_info
))
1768 /* The original sets may now be killed. */
1769 delete_insn (insn_a
);
1771 /* Several special cases here: First, we may have reused insn_b above,
1772 in which case insn_b is now NULL. Second, we want to delete insn_b
1773 if it came from the ELSE block, because follows the now correct
1774 write that appears in the TEST block. However, if we got insn_b from
1775 the TEST block, it may in fact be loading data needed for the comparison.
1776 We'll let life_analysis remove the insn if it's really dead. */
1777 if (insn_b
&& else_bb
)
1778 delete_insn (insn_b
);
1780 /* The new insns will have been inserted before cond_earliest. We should
1781 be able to remove the jump with impunity, but the condition itself may
1782 have been modified by gcse to be shared across basic blocks. */
1785 /* If we used a temporary, fix it up now. */
1789 noce_emit_move_insn (orig_x
, x
);
1790 insn_b
= gen_sequence ();
1793 emit_insn_after (insn_b
, test_bb
->end
);
1796 /* Merge the blocks! */
1797 merge_if_block (test_bb
, then_bb
, else_bb
, join_bb
);
1802 /* Attempt to convert an IF-THEN or IF-THEN-ELSE block into
1803 straight line code. Return true if successful. */
1806 process_if_block (test_bb
, then_bb
, else_bb
, join_bb
)
1807 basic_block test_bb
; /* Basic block test is in */
1808 basic_block then_bb
; /* Basic block for THEN block */
1809 basic_block else_bb
; /* Basic block for ELSE block */
1810 basic_block join_bb
; /* Basic block the join label is in */
1812 if (! reload_completed
1813 && noce_process_if_block (test_bb
, then_bb
, else_bb
, join_bb
))
1816 if (HAVE_conditional_execution
1818 && cond_exec_process_if_block (test_bb
, then_bb
, else_bb
, join_bb
))
1824 /* Merge the blocks and mark for local life update. */
1827 merge_if_block (test_bb
, then_bb
, else_bb
, join_bb
)
1828 basic_block test_bb
; /* Basic block test is in */
1829 basic_block then_bb
; /* Basic block for THEN block */
1830 basic_block else_bb
; /* Basic block for ELSE block */
1831 basic_block join_bb
; /* Basic block the join label is in */
1833 basic_block combo_bb
;
1835 /* All block merging is done into the lower block numbers. */
1839 /* First merge TEST block into THEN block. This is a no-brainer since
1840 the THEN block did not have a code label to begin with. */
1843 COPY_REG_SET (combo_bb
->global_live_at_end
, then_bb
->global_live_at_end
);
1844 merge_blocks_nomove (combo_bb
, then_bb
);
1845 num_removed_blocks
++;
1847 /* The ELSE block, if it existed, had a label. That label count
1848 will almost always be zero, but odd things can happen when labels
1849 get their addresses taken. */
1852 merge_blocks_nomove (combo_bb
, else_bb
);
1853 num_removed_blocks
++;
1856 /* If there was no join block reported, that means it was not adjacent
1857 to the others, and so we cannot merge them. */
1861 /* The outgoing edge for the current COMBO block should already
1862 be correct. Verify this. */
1863 if (combo_bb
->succ
== NULL_EDGE
)
1866 /* There should still be a branch at the end of the THEN or ELSE
1867 blocks taking us to our final destination. */
1868 if (GET_CODE (combo_bb
->end
) != JUMP_INSN
)
1872 /* The JOIN block may have had quite a number of other predecessors too.
1873 Since we've already merged the TEST, THEN and ELSE blocks, we should
1874 have only one remaining edge from our if-then-else diamond. If there
1875 is more than one remaining edge, it must come from elsewhere. There
1876 may be zero incoming edges if the THEN block didn't actually join
1877 back up (as with a call to abort). */
1878 else if ((join_bb
->pred
== NULL
1879 || join_bb
->pred
->pred_next
== NULL
)
1880 && join_bb
!= EXIT_BLOCK_PTR
)
1882 /* We can merge the JOIN. */
1884 COPY_REG_SET (combo_bb
->global_live_at_end
,
1885 join_bb
->global_live_at_end
);
1886 merge_blocks_nomove (combo_bb
, join_bb
);
1887 num_removed_blocks
++;
1891 /* We cannot merge the JOIN. */
1893 /* The outgoing edge for the current COMBO block should already
1894 be correct. Verify this. */
1895 if (combo_bb
->succ
->succ_next
!= NULL_EDGE
1896 || combo_bb
->succ
->dest
!= join_bb
)
1899 /* Remove the jump and cruft from the end of the COMBO block. */
1900 if (join_bb
!= EXIT_BLOCK_PTR
)
1901 tidy_fallthru_edge (combo_bb
->succ
, combo_bb
, join_bb
);
1904 /* Make sure we update life info properly. */
1905 SET_UPDATE_LIFE (combo_bb
);
1907 num_updated_if_blocks
++;
1910 /* Find a block ending in a simple IF condition. Return TRUE if
1911 we were able to transform it in some way. */
1914 find_if_header (test_bb
)
1915 basic_block test_bb
;
1920 /* The kind of block we're looking for has exactly two successors. */
1921 if ((then_edge
= test_bb
->succ
) == NULL_EDGE
1922 || (else_edge
= then_edge
->succ_next
) == NULL_EDGE
1923 || else_edge
->succ_next
!= NULL_EDGE
)
1926 /* Neither edge should be abnormal. */
1927 if ((then_edge
->flags
& EDGE_COMPLEX
)
1928 || (else_edge
->flags
& EDGE_COMPLEX
))
1931 /* The THEN edge is canonically the one that falls through. */
1932 if (then_edge
->flags
& EDGE_FALLTHRU
)
1934 else if (else_edge
->flags
& EDGE_FALLTHRU
)
1937 else_edge
= then_edge
;
1941 /* Otherwise this must be a multiway branch of some sort. */
1944 if (find_if_block (test_bb
, then_edge
, else_edge
))
1946 if (HAVE_trap
&& HAVE_conditional_trap
1947 && find_cond_trap (test_bb
, then_edge
, else_edge
))
1950 && (! HAVE_conditional_execution
|| reload_completed
))
1952 if (find_if_case_1 (test_bb
, then_edge
, else_edge
))
1954 if (find_if_case_2 (test_bb
, then_edge
, else_edge
))
1962 fprintf (rtl_dump_file
, "Conversion succeeded.\n");
1966 /* Determine if a given basic block heads a simple IF-THEN or IF-THEN-ELSE
1967 block. If so, we'll try to convert the insns to not require the branch.
1968 Return TRUE if we were successful at converting the the block. */
1971 find_if_block (test_bb
, then_edge
, else_edge
)
1972 basic_block test_bb
;
1973 edge then_edge
, else_edge
;
1975 basic_block then_bb
= then_edge
->dest
;
1976 basic_block else_bb
= else_edge
->dest
;
1977 basic_block join_bb
= NULL_BLOCK
;
1978 edge then_succ
= then_bb
->succ
;
1979 edge else_succ
= else_bb
->succ
;
1982 /* The THEN block of an IF-THEN combo must have exactly one predecessor. */
1983 if (then_bb
->pred
->pred_next
!= NULL_EDGE
)
1986 /* The THEN block of an IF-THEN combo must have zero or one successors. */
1987 if (then_succ
!= NULL_EDGE
1988 && (then_succ
->succ_next
!= NULL_EDGE
1989 || (then_succ
->flags
& EDGE_COMPLEX
)))
1992 /* If the THEN block has no successors, conditional execution can still
1993 make a conditional call. Don't do this unless the ELSE block has
1994 only one incoming edge -- the CFG manipulation is too ugly otherwise.
1995 Check for the last insn of the THEN block being an indirect jump, which
1996 is listed as not having any successors, but confuses the rest of the CE
1997 code processing. XXX we should fix this in the future. */
1998 if (then_succ
== NULL
)
2000 if (else_bb
->pred
->pred_next
== NULL_EDGE
)
2002 rtx last_insn
= then_bb
->end
;
2005 && GET_CODE (last_insn
) == NOTE
2006 && last_insn
!= then_bb
->head
)
2007 last_insn
= PREV_INSN (last_insn
);
2010 && GET_CODE (last_insn
) == JUMP_INSN
2011 && ! simplejump_p (last_insn
))
2015 else_bb
= NULL_BLOCK
;
2021 /* If the THEN block's successor is the other edge out of the TEST block,
2022 then we have an IF-THEN combo without an ELSE. */
2023 else if (then_succ
->dest
== else_bb
)
2026 else_bb
= NULL_BLOCK
;
2029 /* If the THEN and ELSE block meet in a subsequent block, and the ELSE
2030 has exactly one predecessor and one successor, and the outgoing edge
2031 is not complex, then we have an IF-THEN-ELSE combo. */
2032 else if (else_succ
!= NULL_EDGE
2033 && then_succ
->dest
== else_succ
->dest
2034 && else_bb
->pred
->pred_next
== NULL_EDGE
2035 && else_succ
->succ_next
== NULL_EDGE
2036 && ! (else_succ
->flags
& EDGE_COMPLEX
))
2037 join_bb
= else_succ
->dest
;
2039 /* Otherwise it is not an IF-THEN or IF-THEN-ELSE combination. */
2043 num_possible_if_blocks
++;
2048 fprintf (rtl_dump_file
,
2049 "\nIF-THEN-ELSE block found, start %d, then %d, else %d, join %d\n",
2050 test_bb
->index
, then_bb
->index
, else_bb
->index
,
2053 fprintf (rtl_dump_file
,
2054 "\nIF-THEN block found, start %d, then %d, join %d\n",
2055 test_bb
->index
, then_bb
->index
, join_bb
->index
);
2058 /* Make sure IF, THEN, and ELSE, blocks are adjacent. Actually, we
2059 get the first condition for free, since we've already asserted that
2060 there's a fallthru edge from IF to THEN. */
2061 /* ??? As an enhancement, move the ELSE block. Have to deal with
2062 BLOCK notes, if by no other means than aborting the merge if they
2063 exist. Sticky enough I don't want to think about it now. */
2064 next_index
= then_bb
->index
;
2065 if (else_bb
&& ++next_index
!= else_bb
->index
)
2067 if (++next_index
!= join_bb
->index
&& join_bb
->index
!= EXIT_BLOCK
)
2075 /* Do the real work. */
2076 return process_if_block (test_bb
, then_bb
, else_bb
, join_bb
);
2079 /* Convert a branch over a trap, or a branch to a trap,
2080 into a conditional trap. */
2083 find_cond_trap (test_bb
, then_edge
, else_edge
)
2084 basic_block test_bb
;
2085 edge then_edge
, else_edge
;
2087 basic_block then_bb
, else_bb
, join_bb
, trap_bb
;
2088 rtx trap
, jump
, cond
, cond_earliest
, seq
;
2091 then_bb
= then_edge
->dest
;
2092 else_bb
= else_edge
->dest
;
2095 /* Locate the block with the trap instruction. */
2096 /* ??? While we look for no successors, we really ought to allow
2097 EH successors. Need to fix merge_if_block for that to work. */
2098 /* ??? We can't currently handle merging the blocks if they are not
2099 already adjacent. Prevent losage in merge_if_block by detecting
2101 if (then_bb
->succ
== NULL
)
2104 if (else_bb
->index
!= then_bb
->index
+ 1)
2109 else if (else_bb
->succ
== NULL
)
2112 if (else_bb
->index
!= then_bb
->index
+ 1)
2114 else if (then_bb
->succ
2115 && ! then_bb
->succ
->succ_next
2116 && ! (then_bb
->succ
->flags
& EDGE_COMPLEX
)
2117 && then_bb
->succ
->dest
->index
== else_bb
->index
+ 1)
2118 join_bb
= then_bb
->succ
->dest
;
2123 /* Don't confuse a conditional return with something we want to
2125 if (trap_bb
== EXIT_BLOCK_PTR
)
2128 /* The only instruction in the THEN block must be the trap. */
2129 trap
= first_active_insn (trap_bb
);
2130 if (! (trap
== trap_bb
->end
2131 && GET_CODE (PATTERN (trap
)) == TRAP_IF
2132 && TRAP_CONDITION (PATTERN (trap
)) == const_true_rtx
))
2137 if (trap_bb
== then_bb
)
2138 fprintf (rtl_dump_file
,
2139 "\nTRAP-IF block found, start %d, trap %d",
2140 test_bb
->index
, then_bb
->index
);
2142 fprintf (rtl_dump_file
,
2143 "\nTRAP-IF block found, start %d, then %d, trap %d",
2144 test_bb
->index
, then_bb
->index
, trap_bb
->index
);
2146 fprintf (rtl_dump_file
, ", join %d\n", join_bb
->index
);
2148 fputc ('\n', rtl_dump_file
);
2151 /* If this is not a standard conditional jump, we can't parse it. */
2152 jump
= test_bb
->end
;
2153 cond
= noce_get_condition (jump
, &cond_earliest
);
2157 /* If the conditional jump is more than just a conditional jump,
2158 then we can not do if-conversion on this block. */
2159 if (! onlyjump_p (jump
))
2162 /* We must be comparing objects whose modes imply the size. */
2163 if (GET_MODE (XEXP (cond
, 0)) == BLKmode
)
2166 /* Reverse the comparison code, if necessary. */
2167 code
= GET_CODE (cond
);
2168 if (then_bb
== trap_bb
)
2170 code
= reversed_comparison_code (cond
, jump
);
2171 if (code
== UNKNOWN
)
2175 /* Attempt to generate the conditional trap. */
2176 seq
= gen_cond_trap (code
, XEXP (cond
, 0), XEXP (cond
, 1),
2177 TRAP_CODE (PATTERN (trap
)));
2181 /* Emit the new insns before cond_earliest; delete the old jump
2184 emit_insn_before (seq
, cond_earliest
);
2190 /* Merge the blocks! */
2191 if (trap_bb
!= then_bb
&& ! else_bb
)
2193 flow_delete_block (trap_bb
);
2194 num_removed_blocks
++;
2196 merge_if_block (test_bb
, then_bb
, else_bb
, join_bb
);
2201 /* Look for IF-THEN-ELSE cases in which one of THEN or ELSE is
2202 transformable, but not necessarily the other. There need be no
2205 Return TRUE if we were successful at converting the the block.
2207 Cases we'd like to look at:
2210 if (test) goto over; // x not live
2218 if (! test) goto label;
2221 if (test) goto E; // x not live
2235 (3) // This one's really only interesting for targets that can do
2236 // multiway branching, e.g. IA-64 BBB bundles. For other targets
2237 // it results in multiple branches on a cache line, which often
2238 // does not sit well with predictors.
2240 if (test1) goto E; // predicted not taken
2256 (A) Don't do (2) if the branch is predicted against the block we're
2257 eliminating. Do it anyway if we can eliminate a branch; this requires
2258 that the sole successor of the eliminated block postdominate the other
2261 (B) With CE, on (3) we can steal from both sides of the if, creating
2270 Again, this is most useful if J postdominates.
2272 (C) CE substitutes for helpful life information.
2274 (D) These heuristics need a lot of work. */
2276 /* Tests for case 1 above. */
2279 find_if_case_1 (test_bb
, then_edge
, else_edge
)
2280 basic_block test_bb
;
2281 edge then_edge
, else_edge
;
2283 basic_block then_bb
= then_edge
->dest
;
2284 basic_block else_bb
= else_edge
->dest
, new_bb
;
2285 edge then_succ
= then_bb
->succ
;
2287 /* THEN has one successor. */
2288 if (!then_succ
|| then_succ
->succ_next
!= NULL
)
2291 /* THEN does not fall through, but is not strange either. */
2292 if (then_succ
->flags
& (EDGE_COMPLEX
| EDGE_FALLTHRU
))
2295 /* THEN has one predecessor. */
2296 if (then_bb
->pred
->pred_next
!= NULL
)
2299 /* THEN must do something. */
2300 if (forwarder_block_p (then_bb
))
2303 num_possible_if_blocks
++;
2305 fprintf (rtl_dump_file
,
2306 "\nIF-CASE-1 found, start %d, then %d\n",
2307 test_bb
->index
, then_bb
->index
);
2309 /* THEN is small. */
2310 if (count_bb_insns (then_bb
) > BRANCH_COST
)
2313 /* Registers set are dead, or are predicable. */
2314 if (! dead_or_predicable (test_bb
, then_bb
, else_bb
,
2315 then_bb
->succ
->dest
, 1))
2318 /* Conversion went ok, including moving the insns and fixing up the
2319 jump. Adjust the CFG to match. */
2321 SET_UPDATE_LIFE (test_bb
);
2322 bitmap_operation (test_bb
->global_live_at_end
,
2323 else_bb
->global_live_at_start
,
2324 then_bb
->global_live_at_end
, BITMAP_IOR
);
2326 new_bb
= redirect_edge_and_branch_force (FALLTHRU_EDGE (test_bb
), else_bb
);
2327 /* Make rest of code believe that the newly created block is the THEN_BB
2328 block we are going to remove. */
2331 new_bb
->aux
= then_bb
->aux
;
2332 SET_UPDATE_LIFE (then_bb
);
2334 flow_delete_block (then_bb
);
2335 /* We've possibly created jump to next insn, cleanup_cfg will solve that
2338 num_removed_blocks
++;
2339 num_updated_if_blocks
++;
2344 /* Test for case 2 above. */
2347 find_if_case_2 (test_bb
, then_edge
, else_edge
)
2348 basic_block test_bb
;
2349 edge then_edge
, else_edge
;
2351 basic_block then_bb
= then_edge
->dest
;
2352 basic_block else_bb
= else_edge
->dest
;
2353 edge else_succ
= else_bb
->succ
;
2356 /* ELSE has one successor. */
2357 if (!else_succ
|| else_succ
->succ_next
!= NULL
)
2360 /* ELSE outgoing edge is not complex. */
2361 if (else_succ
->flags
& EDGE_COMPLEX
)
2364 /* ELSE has one predecessor. */
2365 if (else_bb
->pred
->pred_next
!= NULL
)
2368 /* THEN is not EXIT. */
2369 if (then_bb
->index
< 0)
2372 /* ELSE is predicted or SUCC(ELSE) postdominates THEN. */
2373 note
= find_reg_note (test_bb
->end
, REG_BR_PROB
, NULL_RTX
);
2374 if (note
&& INTVAL (XEXP (note
, 0)) >= REG_BR_PROB_BASE
/ 2)
2376 else if (else_succ
->dest
->index
< 0
2377 || TEST_BIT (post_dominators
[ORIG_INDEX (then_bb
)],
2378 ORIG_INDEX (else_succ
->dest
)))
2383 num_possible_if_blocks
++;
2385 fprintf (rtl_dump_file
,
2386 "\nIF-CASE-2 found, start %d, else %d\n",
2387 test_bb
->index
, else_bb
->index
);
2389 /* ELSE is small. */
2390 if (count_bb_insns (then_bb
) > BRANCH_COST
)
2393 /* Registers set are dead, or are predicable. */
2394 if (! dead_or_predicable (test_bb
, else_bb
, then_bb
, else_succ
->dest
, 0))
2397 /* Conversion went ok, including moving the insns and fixing up the
2398 jump. Adjust the CFG to match. */
2400 SET_UPDATE_LIFE (test_bb
);
2401 bitmap_operation (test_bb
->global_live_at_end
,
2402 then_bb
->global_live_at_start
,
2403 else_bb
->global_live_at_end
, BITMAP_IOR
);
2405 flow_delete_block (else_bb
);
2407 num_removed_blocks
++;
2408 num_updated_if_blocks
++;
2410 /* ??? We may now fallthru from one of THEN's successors into a join
2411 block. Rerun cleanup_cfg? Examine things manually? Wait? */
2416 /* A subroutine of dead_or_predicable called through for_each_rtx.
2417 Return 1 if a memory is found. */
2420 find_memory (px
, data
)
2422 void *data ATTRIBUTE_UNUSED
;
2424 return GET_CODE (*px
) == MEM
;
2427 /* Used by the code above to perform the actual rtl transformations.
2428 Return TRUE if successful.
2430 TEST_BB is the block containing the conditional branch. MERGE_BB
2431 is the block containing the code to manipulate. NEW_DEST is the
2432 label TEST_BB should be branching to after the conversion.
2433 REVERSEP is true if the sense of the branch should be reversed. */
2436 dead_or_predicable (test_bb
, merge_bb
, other_bb
, new_dest
, reversep
)
2437 basic_block test_bb
, merge_bb
, other_bb
;
2438 basic_block new_dest
;
2441 rtx head
, end
, jump
, earliest
, old_dest
, new_label
;
2443 jump
= test_bb
->end
;
2445 /* Find the extent of the real code in the merge block. */
2446 head
= merge_bb
->head
;
2447 end
= merge_bb
->end
;
2449 if (GET_CODE (head
) == CODE_LABEL
)
2450 head
= NEXT_INSN (head
);
2451 if (GET_CODE (head
) == NOTE
)
2455 head
= end
= NULL_RTX
;
2458 head
= NEXT_INSN (head
);
2461 if (GET_CODE (end
) == JUMP_INSN
)
2465 head
= end
= NULL_RTX
;
2468 end
= PREV_INSN (end
);
2471 /* Disable handling dead code by conditional execution if the machine needs
2472 to do anything funny with the tests, etc. */
2473 #ifndef IFCVT_MODIFY_TESTS
2474 if (HAVE_conditional_execution
)
2476 /* In the conditional execution case, we have things easy. We know
2477 the condition is reversable. We don't have to check life info,
2478 becase we're going to conditionally execute the code anyway.
2479 All that's left is making sure the insns involved can actually
2484 cond
= cond_exec_get_condition (jump
);
2488 prob_val
= find_reg_note (jump
, REG_BR_PROB
, NULL_RTX
);
2490 prob_val
= XEXP (prob_val
, 0);
2494 enum rtx_code rev
= reversed_comparison_code (cond
, jump
);
2497 cond
= gen_rtx_fmt_ee (rev
, GET_MODE (cond
), XEXP (cond
, 0),
2500 prob_val
= GEN_INT (REG_BR_PROB_BASE
- INTVAL (prob_val
));
2503 if (! cond_exec_process_insns (head
, end
, cond
, prob_val
, 0))
2511 /* In the non-conditional execution case, we have to verify that there
2512 are no trapping operations, no calls, no references to memory, and
2513 that any registers modified are dead at the branch site. */
2515 rtx insn
, cond
, prev
;
2516 regset_head merge_set_head
, tmp_head
, test_live_head
, test_set_head
;
2517 regset merge_set
, tmp
, test_live
, test_set
;
2518 struct propagate_block_info
*pbi
;
2521 /* Check for no calls or trapping operations. */
2522 for (insn
= head
; ; insn
= NEXT_INSN (insn
))
2524 if (GET_CODE (insn
) == CALL_INSN
)
2528 if (may_trap_p (PATTERN (insn
)))
2531 /* ??? Even non-trapping memories such as stack frame
2532 references must be avoided. For stores, we collect
2533 no lifetime info; for reads, we'd have to assert
2534 true_dependence false against every store in the
2536 if (for_each_rtx (&PATTERN (insn
), find_memory
, NULL
))
2543 if (! any_condjump_p (jump
))
2546 /* Find the extent of the conditional. */
2547 cond
= noce_get_condition (jump
, &earliest
);
2552 MERGE_SET = set of registers set in MERGE_BB
2553 TEST_LIVE = set of registers live at EARLIEST
2554 TEST_SET = set of registers set between EARLIEST and the
2555 end of the block. */
2557 tmp
= INITIALIZE_REG_SET (tmp_head
);
2558 merge_set
= INITIALIZE_REG_SET (merge_set_head
);
2559 test_live
= INITIALIZE_REG_SET (test_live_head
);
2560 test_set
= INITIALIZE_REG_SET (test_set_head
);
2562 /* ??? bb->local_set is only valid during calculate_global_regs_live,
2563 so we must recompute usage for MERGE_BB. Not so bad, I suppose,
2564 since we've already asserted that MERGE_BB is small. */
2565 propagate_block (merge_bb
, tmp
, merge_set
, merge_set
, 0);
2567 /* For small register class machines, don't lengthen lifetimes of
2568 hard registers before reload. */
2569 if (SMALL_REGISTER_CLASSES
&& ! reload_completed
)
2571 EXECUTE_IF_SET_IN_BITMAP
2574 if (i
< FIRST_PSEUDO_REGISTER
2576 && ! global_regs
[i
])
2581 /* For TEST, we're interested in a range of insns, not a whole block.
2582 Moreover, we're interested in the insns live from OTHER_BB. */
2584 COPY_REG_SET (test_live
, other_bb
->global_live_at_start
);
2585 pbi
= init_propagate_block_info (test_bb
, test_live
, test_set
, test_set
,
2588 for (insn
= jump
; ; insn
= prev
)
2590 prev
= propagate_one_insn (pbi
, insn
);
2591 if (insn
== earliest
)
2595 free_propagate_block_info (pbi
);
2597 /* We can perform the transformation if
2598 MERGE_SET & (TEST_SET | TEST_LIVE)
2600 TEST_SET & merge_bb->global_live_at_start
2603 bitmap_operation (tmp
, test_set
, test_live
, BITMAP_IOR
);
2604 bitmap_operation (tmp
, tmp
, merge_set
, BITMAP_AND
);
2605 EXECUTE_IF_SET_IN_BITMAP(tmp
, 0, i
, fail
= 1);
2607 bitmap_operation (tmp
, test_set
, merge_bb
->global_live_at_start
,
2609 EXECUTE_IF_SET_IN_BITMAP(tmp
, 0, i
, fail
= 1);
2612 FREE_REG_SET (merge_set
);
2613 FREE_REG_SET (test_live
);
2614 FREE_REG_SET (test_set
);
2621 /* We don't want to use normal invert_jump or redirect_jump because
2622 we don't want to delete_insn called. Also, we want to do our own
2623 change group management. */
2625 old_dest
= JUMP_LABEL (jump
);
2626 new_label
= block_label (new_dest
);
2628 ? ! invert_jump_1 (jump
, new_label
)
2629 : ! redirect_jump_1 (jump
, new_label
))
2632 if (! apply_change_group ())
2636 LABEL_NUSES (old_dest
) -= 1;
2638 LABEL_NUSES (new_label
) += 1;
2639 JUMP_LABEL (jump
) = new_label
;
2642 invert_br_probabilities (jump
);
2644 redirect_edge_succ (BRANCH_EDGE (test_bb
), new_dest
);
2647 gcov_type count
, probability
;
2648 count
= BRANCH_EDGE (test_bb
)->count
;
2649 BRANCH_EDGE (test_bb
)->count
= FALLTHRU_EDGE (test_bb
)->count
;
2650 FALLTHRU_EDGE (test_bb
)->count
= count
;
2651 probability
= BRANCH_EDGE (test_bb
)->probability
;
2652 BRANCH_EDGE (test_bb
)->probability
= FALLTHRU_EDGE (test_bb
)->probability
;
2653 FALLTHRU_EDGE (test_bb
)->probability
= probability
;
2656 /* Move the insns out of MERGE_BB to before the branch. */
2659 if (end
== merge_bb
->end
)
2660 merge_bb
->end
= PREV_INSN (head
);
2662 if (squeeze_notes (&head
, &end
))
2665 reorder_insns (head
, end
, PREV_INSN (earliest
));
2674 /* Main entry point for all if-conversion. */
2677 if_convert (x_life_data_ok
)
2682 num_possible_if_blocks
= 0;
2683 num_updated_if_blocks
= 0;
2684 num_removed_blocks
= 0;
2685 life_data_ok
= (x_life_data_ok
!= 0);
2687 /* Free up basic_block_for_insn so that we don't have to keep it
2688 up to date, either here or in merge_blocks_nomove. */
2689 free_basic_block_vars (1);
2691 /* Compute postdominators if we think we'll use them. */
2692 post_dominators
= NULL
;
2693 if (HAVE_conditional_execution
|| life_data_ok
)
2695 post_dominators
= sbitmap_vector_alloc (n_basic_blocks
, n_basic_blocks
);
2696 calculate_dominance_info (NULL
, post_dominators
, CDI_POST_DOMINATORS
);
2699 /* Record initial block numbers. */
2700 for (block_num
= 0; block_num
< n_basic_blocks
; block_num
++)
2701 SET_ORIG_INDEX (BASIC_BLOCK (block_num
), block_num
);
2703 /* Go through each of the basic blocks looking for things to convert. */
2704 for (block_num
= 0; block_num
< n_basic_blocks
; )
2706 basic_block bb
= BASIC_BLOCK (block_num
);
2707 if (find_if_header (bb
))
2708 block_num
= bb
->index
;
2713 if (post_dominators
)
2714 sbitmap_vector_free (post_dominators
);
2717 fflush (rtl_dump_file
);
2719 /* Rebuild life info for basic blocks that require it. */
2720 if (num_removed_blocks
&& life_data_ok
)
2722 sbitmap update_life_blocks
= sbitmap_alloc (n_basic_blocks
);
2723 sbitmap_zero (update_life_blocks
);
2725 /* If we allocated new pseudos, we must resize the array for sched1. */
2726 if (max_regno
< max_reg_num ())
2728 max_regno
= max_reg_num ();
2729 allocate_reg_info (max_regno
, FALSE
, FALSE
);
2732 for (block_num
= 0; block_num
< n_basic_blocks
; block_num
++)
2733 if (UPDATE_LIFE (BASIC_BLOCK (block_num
)))
2734 SET_BIT (update_life_blocks
, block_num
);
2736 count_or_remove_death_notes (update_life_blocks
, 1);
2737 /* ??? See about adding a mode that verifies that the initial
2738 set of blocks don't let registers come live. */
2739 update_life_info (update_life_blocks
, UPDATE_LIFE_GLOBAL
,
2740 PROP_DEATH_NOTES
| PROP_SCAN_DEAD_CODE
2741 | PROP_KILL_DEAD_CODE
);
2743 sbitmap_free (update_life_blocks
);
2745 clear_aux_for_blocks ();
2747 /* Write the final stats. */
2748 if (rtl_dump_file
&& num_possible_if_blocks
> 0)
2750 fprintf (rtl_dump_file
,
2751 "\n%d possible IF blocks searched.\n",
2752 num_possible_if_blocks
);
2753 fprintf (rtl_dump_file
,
2754 "%d IF blocks converted.\n",
2755 num_updated_if_blocks
);
2756 fprintf (rtl_dump_file
,
2757 "%d basic blocks deleted.\n\n\n",
2758 num_removed_blocks
);
2761 #ifdef ENABLE_CHECKING
2762 verify_flow_info ();