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 a 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
),
584 bitpos
, outmode
, y
, GET_MODE_BITSIZE (inmode
),
585 GET_MODE_BITSIZE (inmode
));
588 /* Convert "if (test) x = 1; else x = 0".
590 Only try 0 and STORE_FLAG_VALUE here. Other combinations will be
591 tried in noce_try_store_flag_constants after noce_try_cmove has had
592 a go at the conversion. */
595 noce_try_store_flag (if_info
)
596 struct noce_if_info
*if_info
;
601 if (GET_CODE (if_info
->b
) == CONST_INT
602 && INTVAL (if_info
->b
) == STORE_FLAG_VALUE
603 && if_info
->a
== const0_rtx
)
605 else if (if_info
->b
== const0_rtx
606 && GET_CODE (if_info
->a
) == CONST_INT
607 && INTVAL (if_info
->a
) == STORE_FLAG_VALUE
608 && (reversed_comparison_code (if_info
->cond
, if_info
->jump
)
616 target
= noce_emit_store_flag (if_info
, if_info
->x
, reversep
, 0);
619 if (target
!= if_info
->x
)
620 noce_emit_move_insn (if_info
->x
, target
);
624 emit_insns_before (seq
, if_info
->cond_earliest
);
635 /* Convert "if (test) x = a; else x = b", for A and B constant. */
638 noce_try_store_flag_constants (if_info
)
639 struct noce_if_info
*if_info
;
643 HOST_WIDE_INT itrue
, ifalse
, diff
, tmp
;
644 int normalize
, can_reverse
;
645 enum machine_mode mode
;
648 && GET_CODE (if_info
->a
) == CONST_INT
649 && GET_CODE (if_info
->b
) == CONST_INT
)
651 mode
= GET_MODE (if_info
->x
);
652 ifalse
= INTVAL (if_info
->a
);
653 itrue
= INTVAL (if_info
->b
);
654 diff
= trunc_int_for_mode (itrue
- ifalse
, mode
);
656 can_reverse
= (reversed_comparison_code (if_info
->cond
, if_info
->jump
)
660 if (diff
== STORE_FLAG_VALUE
|| diff
== -STORE_FLAG_VALUE
)
662 else if (ifalse
== 0 && exact_log2 (itrue
) >= 0
663 && (STORE_FLAG_VALUE
== 1
664 || BRANCH_COST
>= 2))
666 else if (itrue
== 0 && exact_log2 (ifalse
) >= 0 && can_reverse
667 && (STORE_FLAG_VALUE
== 1 || BRANCH_COST
>= 2))
668 normalize
= 1, reversep
= 1;
670 && (STORE_FLAG_VALUE
== -1
671 || BRANCH_COST
>= 2))
673 else if (ifalse
== -1 && can_reverse
674 && (STORE_FLAG_VALUE
== -1 || BRANCH_COST
>= 2))
675 normalize
= -1, reversep
= 1;
676 else if ((BRANCH_COST
>= 2 && STORE_FLAG_VALUE
== -1)
684 tmp
= itrue
; itrue
= ifalse
; ifalse
= tmp
;
685 diff
= trunc_int_for_mode (-diff
, mode
);
689 target
= noce_emit_store_flag (if_info
, if_info
->x
, reversep
, normalize
);
696 /* if (test) x = 3; else x = 4;
697 => x = 3 + (test == 0); */
698 if (diff
== STORE_FLAG_VALUE
|| diff
== -STORE_FLAG_VALUE
)
700 target
= expand_simple_binop (mode
,
701 (diff
== STORE_FLAG_VALUE
703 GEN_INT (ifalse
), target
, if_info
->x
, 0,
707 /* if (test) x = 8; else x = 0;
708 => x = (test != 0) << 3; */
709 else if (ifalse
== 0 && (tmp
= exact_log2 (itrue
)) >= 0)
711 target
= expand_simple_binop (mode
, ASHIFT
,
712 target
, GEN_INT (tmp
), if_info
->x
, 0,
716 /* if (test) x = -1; else x = b;
717 => x = -(test != 0) | b; */
718 else if (itrue
== -1)
720 target
= expand_simple_binop (mode
, IOR
,
721 target
, GEN_INT (ifalse
), if_info
->x
, 0,
725 /* if (test) x = a; else x = b;
726 => x = (-(test != 0) & (b - a)) + a; */
729 target
= expand_simple_binop (mode
, AND
,
730 target
, GEN_INT (diff
), if_info
->x
, 0,
733 target
= expand_simple_binop (mode
, PLUS
,
734 target
, GEN_INT (ifalse
),
735 if_info
->x
, 0, OPTAB_WIDEN
);
744 if (target
!= if_info
->x
)
745 noce_emit_move_insn (if_info
->x
, target
);
750 if (seq_contains_jump (seq
))
753 emit_insns_before (seq
, if_info
->cond_earliest
);
761 /* Convert "if (test) foo++" into "foo += (test != 0)", and
762 similarly for "foo--". */
765 noce_try_store_flag_inc (if_info
)
766 struct noce_if_info
*if_info
;
769 int subtract
, normalize
;
775 /* Should be no `else' case to worry about. */
776 && if_info
->b
== if_info
->x
777 && GET_CODE (if_info
->a
) == PLUS
778 && (XEXP (if_info
->a
, 1) == const1_rtx
779 || XEXP (if_info
->a
, 1) == constm1_rtx
)
780 && rtx_equal_p (XEXP (if_info
->a
, 0), if_info
->x
)
781 && (reversed_comparison_code (if_info
->cond
, if_info
->jump
)
784 if (STORE_FLAG_VALUE
== INTVAL (XEXP (if_info
->a
, 1)))
785 subtract
= 0, normalize
= 0;
786 else if (-STORE_FLAG_VALUE
== INTVAL (XEXP (if_info
->a
, 1)))
787 subtract
= 1, normalize
= 0;
789 subtract
= 0, normalize
= INTVAL (XEXP (if_info
->a
, 1));
793 target
= noce_emit_store_flag (if_info
,
794 gen_reg_rtx (GET_MODE (if_info
->x
)),
798 target
= expand_simple_binop (GET_MODE (if_info
->x
),
799 subtract
? MINUS
: PLUS
,
800 if_info
->x
, target
, if_info
->x
,
804 if (target
!= if_info
->x
)
805 noce_emit_move_insn (if_info
->x
, target
);
810 if (seq_contains_jump (seq
))
813 emit_insns_before (seq
, if_info
->cond_earliest
);
824 /* Convert "if (test) x = 0;" to "x &= -(test == 0);" */
827 noce_try_store_flag_mask (if_info
)
828 struct noce_if_info
*if_info
;
836 || STORE_FLAG_VALUE
== -1)
837 && ((if_info
->a
== const0_rtx
838 && rtx_equal_p (if_info
->b
, if_info
->x
))
839 || ((reversep
= (reversed_comparison_code (if_info
->cond
,
842 && if_info
->b
== const0_rtx
843 && rtx_equal_p (if_info
->a
, if_info
->x
))))
846 target
= noce_emit_store_flag (if_info
,
847 gen_reg_rtx (GET_MODE (if_info
->x
)),
850 target
= expand_simple_binop (GET_MODE (if_info
->x
), AND
,
851 if_info
->x
, target
, if_info
->x
, 0,
856 if (target
!= if_info
->x
)
857 noce_emit_move_insn (if_info
->x
, target
);
862 if (seq_contains_jump (seq
))
865 emit_insns_before (seq
, if_info
->cond_earliest
);
876 /* Helper function for noce_try_cmove and noce_try_cmove_arith. */
879 noce_emit_cmove (if_info
, x
, code
, cmp_a
, cmp_b
, vfalse
, vtrue
)
880 struct noce_if_info
*if_info
;
881 rtx x
, cmp_a
, cmp_b
, vfalse
, vtrue
;
884 /* If earliest == jump, try to build the cmove insn directly.
885 This is helpful when combine has created some complex condition
886 (like for alpha's cmovlbs) that we can't hope to regenerate
887 through the normal interface. */
889 if (if_info
->cond_earliest
== if_info
->jump
)
893 tmp
= gen_rtx_fmt_ee (code
, GET_MODE (if_info
->cond
), cmp_a
, cmp_b
);
894 tmp
= gen_rtx_IF_THEN_ELSE (GET_MODE (x
), tmp
, vtrue
, vfalse
);
895 tmp
= gen_rtx_SET (VOIDmode
, x
, tmp
);
898 tmp
= emit_insn (tmp
);
900 if (recog_memoized (tmp
) >= 0)
912 /* Don't even try if the comparison operands are weird. */
913 if (! general_operand (cmp_a
, GET_MODE (cmp_a
))
914 || ! general_operand (cmp_b
, GET_MODE (cmp_b
)))
917 #if HAVE_conditional_move
918 return emit_conditional_move (x
, code
, cmp_a
, cmp_b
, VOIDmode
,
919 vtrue
, vfalse
, GET_MODE (x
),
920 (code
== LTU
|| code
== GEU
921 || code
== LEU
|| code
== GTU
));
923 /* We'll never get here, as noce_process_if_block doesn't call the
924 functions involved. Ifdef code, however, should be discouraged
925 because it leads to typos in the code not selected. However,
926 emit_conditional_move won't exist either. */
931 /* Try only simple constants and registers here. More complex cases
932 are handled in noce_try_cmove_arith after noce_try_store_flag_arith
933 has had a go at it. */
936 noce_try_cmove (if_info
)
937 struct noce_if_info
*if_info
;
942 if ((CONSTANT_P (if_info
->a
) || register_operand (if_info
->a
, VOIDmode
))
943 && (CONSTANT_P (if_info
->b
) || register_operand (if_info
->b
, VOIDmode
)))
947 code
= GET_CODE (if_info
->cond
);
948 target
= noce_emit_cmove (if_info
, if_info
->x
, code
,
949 XEXP (if_info
->cond
, 0),
950 XEXP (if_info
->cond
, 1),
951 if_info
->a
, if_info
->b
);
955 if (target
!= if_info
->x
)
956 noce_emit_move_insn (if_info
->x
, target
);
960 emit_insns_before (seq
, if_info
->cond_earliest
);
973 /* Try more complex cases involving conditional_move. */
976 noce_try_cmove_arith (if_info
)
977 struct noce_if_info
*if_info
;
987 /* A conditional move from two memory sources is equivalent to a
988 conditional on their addresses followed by a load. Don't do this
989 early because it'll screw alias analysis. Note that we've
990 already checked for no side effects. */
991 if (! no_new_pseudos
&& cse_not_expected
992 && GET_CODE (a
) == MEM
&& GET_CODE (b
) == MEM
997 x
= gen_reg_rtx (Pmode
);
1001 /* ??? We could handle this if we knew that a load from A or B could
1002 not fault. This is also true if we've already loaded
1003 from the address along the path from ENTRY. */
1004 else if (may_trap_p (a
) || may_trap_p (b
))
1007 /* if (test) x = a + b; else x = c - d;
1014 code
= GET_CODE (if_info
->cond
);
1015 insn_a
= if_info
->insn_a
;
1016 insn_b
= if_info
->insn_b
;
1018 /* Possibly rearrange operands to make things come out more natural. */
1019 if (reversed_comparison_code (if_info
->cond
, if_info
->jump
) != UNKNOWN
)
1022 if (rtx_equal_p (b
, x
))
1024 else if (general_operand (b
, GET_MODE (b
)))
1029 code
= reversed_comparison_code (if_info
->cond
, if_info
->jump
);
1030 tmp
= a
, a
= b
, b
= tmp
;
1031 tmp
= insn_a
, insn_a
= insn_b
, insn_b
= tmp
;
1037 /* If either operand is complex, load it into a register first.
1038 The best way to do this is to copy the original insn. In this
1039 way we preserve any clobbers etc that the insn may have had.
1040 This is of course not possible in the IS_MEM case. */
1041 if (! general_operand (a
, GET_MODE (a
)))
1046 goto end_seq_and_fail
;
1050 tmp
= gen_reg_rtx (GET_MODE (a
));
1051 tmp
= emit_insn (gen_rtx_SET (VOIDmode
, tmp
, a
));
1054 goto end_seq_and_fail
;
1057 a
= gen_reg_rtx (GET_MODE (a
));
1058 tmp
= copy_rtx (insn_a
);
1059 set
= single_set (tmp
);
1061 tmp
= emit_insn (PATTERN (tmp
));
1063 if (recog_memoized (tmp
) < 0)
1064 goto end_seq_and_fail
;
1066 if (! general_operand (b
, GET_MODE (b
)))
1071 goto end_seq_and_fail
;
1075 tmp
= gen_reg_rtx (GET_MODE (b
));
1076 tmp
= emit_insn (gen_rtx_SET (VOIDmode
, tmp
, b
));
1079 goto end_seq_and_fail
;
1082 b
= gen_reg_rtx (GET_MODE (b
));
1083 tmp
= copy_rtx (insn_b
);
1084 set
= single_set (tmp
);
1086 tmp
= emit_insn (PATTERN (tmp
));
1088 if (recog_memoized (tmp
) < 0)
1089 goto end_seq_and_fail
;
1092 target
= noce_emit_cmove (if_info
, x
, code
, XEXP (if_info
->cond
, 0),
1093 XEXP (if_info
->cond
, 1), a
, b
);
1096 goto end_seq_and_fail
;
1098 /* If we're handling a memory for above, emit the load now. */
1101 tmp
= gen_rtx_MEM (GET_MODE (if_info
->x
), target
);
1103 /* Copy over flags as appropriate. */
1104 if (MEM_VOLATILE_P (if_info
->a
) || MEM_VOLATILE_P (if_info
->b
))
1105 MEM_VOLATILE_P (tmp
) = 1;
1106 if (MEM_IN_STRUCT_P (if_info
->a
) && MEM_IN_STRUCT_P (if_info
->b
))
1107 MEM_IN_STRUCT_P (tmp
) = 1;
1108 if (MEM_SCALAR_P (if_info
->a
) && MEM_SCALAR_P (if_info
->b
))
1109 MEM_SCALAR_P (tmp
) = 1;
1110 if (MEM_ALIAS_SET (if_info
->a
) == MEM_ALIAS_SET (if_info
->b
))
1111 set_mem_alias_set (tmp
, MEM_ALIAS_SET (if_info
->a
));
1113 noce_emit_move_insn (if_info
->x
, tmp
);
1115 else if (target
!= x
)
1116 noce_emit_move_insn (x
, target
);
1120 emit_insns_before (tmp
, if_info
->cond_earliest
);
1128 /* For most cases, the simplified condition we found is the best
1129 choice, but this is not the case for the min/max/abs transforms.
1130 For these we wish to know that it is A or B in the condition. */
1133 noce_get_alt_condition (if_info
, target
, earliest
)
1134 struct noce_if_info
*if_info
;
1138 rtx cond
, set
, insn
;
1141 /* If target is already mentioned in the known condition, return it. */
1142 if (reg_mentioned_p (target
, if_info
->cond
))
1144 *earliest
= if_info
->cond_earliest
;
1145 return if_info
->cond
;
1148 set
= pc_set (if_info
->jump
);
1149 cond
= XEXP (SET_SRC (set
), 0);
1151 = GET_CODE (XEXP (SET_SRC (set
), 2)) == LABEL_REF
1152 && XEXP (XEXP (SET_SRC (set
), 2), 0) == JUMP_LABEL (if_info
->jump
);
1154 /* If we're looking for a constant, try to make the conditional
1155 have that constant in it. There are two reasons why it may
1156 not have the constant we want:
1158 1. GCC may have needed to put the constant in a register, because
1159 the target can't compare directly against that constant. For
1160 this case, we look for a SET immediately before the comparison
1161 that puts a constant in that register.
1163 2. GCC may have canonicalized the conditional, for example
1164 replacing "if x < 4" with "if x <= 3". We can undo that (or
1165 make equivalent types of changes) to get the constants we need
1166 if they're off by one in the right direction. */
1168 if (GET_CODE (target
) == CONST_INT
)
1170 enum rtx_code code
= GET_CODE (if_info
->cond
);
1171 rtx op_a
= XEXP (if_info
->cond
, 0);
1172 rtx op_b
= XEXP (if_info
->cond
, 1);
1175 /* First, look to see if we put a constant in a register. */
1176 prev_insn
= PREV_INSN (if_info
->cond_earliest
);
1178 && INSN_P (prev_insn
)
1179 && GET_CODE (PATTERN (prev_insn
)) == SET
)
1181 rtx src
= find_reg_equal_equiv_note (prev_insn
);
1183 src
= SET_SRC (PATTERN (prev_insn
));
1184 if (GET_CODE (src
) == CONST_INT
)
1186 if (rtx_equal_p (op_a
, SET_DEST (PATTERN (prev_insn
))))
1188 else if (rtx_equal_p (op_b
, SET_DEST (PATTERN (prev_insn
))))
1191 if (GET_CODE (op_a
) == CONST_INT
)
1196 code
= swap_condition (code
);
1201 /* Now, look to see if we can get the right constant by
1202 adjusting the conditional. */
1203 if (GET_CODE (op_b
) == CONST_INT
)
1205 HOST_WIDE_INT desired_val
= INTVAL (target
);
1206 HOST_WIDE_INT actual_val
= INTVAL (op_b
);
1211 if (actual_val
== desired_val
+ 1)
1214 op_b
= GEN_INT (desired_val
);
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
);
1243 /* If we made any changes, generate a new conditional that is
1244 equivalent to what we started with, but has the right
1246 if (code
!= GET_CODE (if_info
->cond
)
1247 || op_a
!= XEXP (if_info
->cond
, 0)
1248 || op_b
!= XEXP (if_info
->cond
, 1))
1250 cond
= gen_rtx_fmt_ee (code
, GET_MODE (cond
), op_a
, op_b
);
1251 *earliest
= if_info
->cond_earliest
;
1256 cond
= canonicalize_condition (if_info
->jump
, cond
, reverse
,
1258 if (! cond
|| ! reg_mentioned_p (target
, cond
))
1261 /* We almost certainly searched back to a different place.
1262 Need to re-verify correct lifetimes. */
1264 /* X may not be mentioned in the range (cond_earliest, jump]. */
1265 for (insn
= if_info
->jump
; insn
!= *earliest
; insn
= PREV_INSN (insn
))
1266 if (INSN_P (insn
) && reg_mentioned_p (if_info
->x
, insn
))
1269 /* A and B may not be modified in the range [cond_earliest, jump). */
1270 for (insn
= *earliest
; insn
!= if_info
->jump
; insn
= NEXT_INSN (insn
))
1272 && (modified_in_p (if_info
->a
, insn
)
1273 || modified_in_p (if_info
->b
, insn
)))
1279 /* Convert "if (a < b) x = a; else x = b;" to "x = min(a, b);", etc. */
1282 noce_try_minmax (if_info
)
1283 struct noce_if_info
*if_info
;
1285 rtx cond
, earliest
, target
, seq
;
1286 enum rtx_code code
, op
;
1289 /* ??? Can't guarantee that expand_binop won't create pseudos. */
1293 /* ??? Reject FP modes since we don't know how 0 vs -0 or NaNs
1294 will be resolved with an SMIN/SMAX. It wouldn't be too hard
1295 to get the target to tell us... */
1296 if (FLOAT_MODE_P (GET_MODE (if_info
->x
))
1297 && TARGET_FLOAT_FORMAT
== IEEE_FLOAT_FORMAT
1298 && ! flag_unsafe_math_optimizations
)
1301 cond
= noce_get_alt_condition (if_info
, if_info
->a
, &earliest
);
1305 /* Verify the condition is of the form we expect, and canonicalize
1306 the comparison code. */
1307 code
= GET_CODE (cond
);
1308 if (rtx_equal_p (XEXP (cond
, 0), if_info
->a
))
1310 if (! rtx_equal_p (XEXP (cond
, 1), if_info
->b
))
1313 else if (rtx_equal_p (XEXP (cond
, 1), if_info
->a
))
1315 if (! rtx_equal_p (XEXP (cond
, 0), if_info
->b
))
1317 code
= swap_condition (code
);
1322 /* Determine what sort of operation this is. Note that the code is for
1323 a taken branch, so the code->operation mapping appears backwards. */
1356 target
= expand_simple_binop (GET_MODE (if_info
->x
), op
,
1357 if_info
->a
, if_info
->b
,
1358 if_info
->x
, unsignedp
, OPTAB_WIDEN
);
1364 if (target
!= if_info
->x
)
1365 noce_emit_move_insn (if_info
->x
, target
);
1370 if (seq_contains_jump (seq
))
1373 emit_insns_before (seq
, earliest
);
1374 if_info
->cond
= cond
;
1375 if_info
->cond_earliest
= earliest
;
1380 /* Convert "if (a < 0) x = -a; else x = a;" to "x = abs(a);", etc. */
1383 noce_try_abs (if_info
)
1384 struct noce_if_info
*if_info
;
1386 rtx cond
, earliest
, target
, seq
, a
, b
, c
;
1389 /* ??? Can't guarantee that expand_binop won't create pseudos. */
1393 /* Recognize A and B as constituting an ABS or NABS. */
1396 if (GET_CODE (a
) == NEG
&& rtx_equal_p (XEXP (a
, 0), b
))
1398 else if (GET_CODE (b
) == NEG
&& rtx_equal_p (XEXP (b
, 0), a
))
1400 c
= a
; a
= b
; b
= c
;
1406 cond
= noce_get_alt_condition (if_info
, b
, &earliest
);
1410 /* Verify the condition is of the form we expect. */
1411 if (rtx_equal_p (XEXP (cond
, 0), b
))
1413 else if (rtx_equal_p (XEXP (cond
, 1), b
))
1418 /* Verify that C is zero. Search backward through the block for
1419 a REG_EQUAL note if necessary. */
1422 rtx insn
, note
= NULL
;
1423 for (insn
= earliest
;
1424 insn
!= if_info
->test_bb
->head
;
1425 insn
= PREV_INSN (insn
))
1427 && ((note
= find_reg_note (insn
, REG_EQUAL
, c
))
1428 || (note
= find_reg_note (insn
, REG_EQUIV
, c
))))
1434 if (GET_CODE (c
) == MEM
1435 && GET_CODE (XEXP (c
, 0)) == SYMBOL_REF
1436 && CONSTANT_POOL_ADDRESS_P (XEXP (c
, 0)))
1437 c
= get_pool_constant (XEXP (c
, 0));
1439 /* Work around funny ideas get_condition has wrt canonicalization.
1440 Note that these rtx constants are known to be CONST_INT, and
1441 therefore imply integer comparisons. */
1442 if (c
== constm1_rtx
&& GET_CODE (cond
) == GT
)
1444 else if (c
== const1_rtx
&& GET_CODE (cond
) == LT
)
1446 else if (c
!= CONST0_RTX (GET_MODE (b
)))
1449 /* Determine what sort of operation this is. */
1450 switch (GET_CODE (cond
))
1469 target
= expand_simple_unop (GET_MODE (if_info
->x
), ABS
, b
, if_info
->x
, 0);
1471 /* ??? It's a quandry whether cmove would be better here, especially
1472 for integers. Perhaps combine will clean things up. */
1473 if (target
&& negate
)
1474 target
= expand_simple_unop (GET_MODE (target
), NEG
, target
, if_info
->x
, 0);
1482 if (target
!= if_info
->x
)
1483 noce_emit_move_insn (if_info
->x
, target
);
1488 if (seq_contains_jump (seq
))
1491 emit_insns_before (seq
, earliest
);
1492 if_info
->cond
= cond
;
1493 if_info
->cond_earliest
= earliest
;
1498 /* Look for the condition for the jump first. We'd prefer to avoid
1499 get_condition if we can -- it tries to look back for the contents
1500 of an original compare. On targets that use normal integers for
1501 comparisons, e.g. alpha, this is wasteful. */
1504 noce_get_condition (jump
, earliest
)
1511 /* If the condition variable is a register and is MODE_INT, accept it.
1512 Otherwise, fall back on get_condition. */
1514 if (! any_condjump_p (jump
))
1517 set
= pc_set (jump
);
1519 cond
= XEXP (SET_SRC (set
), 0);
1520 if (GET_CODE (XEXP (cond
, 0)) == REG
1521 && GET_MODE_CLASS (GET_MODE (XEXP (cond
, 0))) == MODE_INT
)
1525 /* If this branches to JUMP_LABEL when the condition is false,
1526 reverse the condition. */
1527 if (GET_CODE (XEXP (SET_SRC (set
), 2)) == LABEL_REF
1528 && XEXP (XEXP (SET_SRC (set
), 2), 0) == JUMP_LABEL (jump
))
1529 cond
= gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond
)),
1530 GET_MODE (cond
), XEXP (cond
, 0),
1534 cond
= get_condition (jump
, earliest
);
1539 /* Return true if OP is ok for if-then-else processing. */
1542 noce_operand_ok (op
)
1545 /* We special-case memories, so handle any of them with
1546 no address side effects. */
1547 if (GET_CODE (op
) == MEM
)
1548 return ! side_effects_p (XEXP (op
, 0));
1550 if (side_effects_p (op
))
1553 /* ??? Unfortuantely may_trap_p can't look at flag_trapping_math, due to
1554 being linked into the genfoo programs. This is probably a mistake.
1555 With finite operands, most fp operations don't trap. */
1556 if (!flag_trapping_math
&& FLOAT_MODE_P (GET_MODE (op
)))
1557 switch (GET_CODE (op
))
1563 /* ??? This is kinda lame -- almost every target will have forced
1564 the constant into a register first. But given the expense of
1565 division, this is probably for the best. */
1566 return (CONSTANT_P (XEXP (op
, 1))
1567 && XEXP (op
, 1) != CONST0_RTX (GET_MODE (op
))
1568 && ! may_trap_p (XEXP (op
, 0)));
1571 switch (GET_RTX_CLASS (GET_CODE (op
)))
1574 return ! may_trap_p (XEXP (op
, 0));
1577 return ! may_trap_p (XEXP (op
, 0)) && ! may_trap_p (XEXP (op
, 1));
1582 return ! may_trap_p (op
);
1585 /* Given a simple IF-THEN or IF-THEN-ELSE block, attempt to convert it
1586 without using conditional execution. Return TRUE if we were
1587 successful at converting the the block. */
1590 noce_process_if_block (test_bb
, then_bb
, else_bb
, join_bb
)
1591 basic_block test_bb
; /* Basic block test is in */
1592 basic_block then_bb
; /* Basic block for THEN block */
1593 basic_block else_bb
; /* Basic block for ELSE block */
1594 basic_block join_bb
; /* Basic block the join label is in */
1596 /* We're looking for patterns of the form
1598 (1) if (...) x = a; else x = b;
1599 (2) x = b; if (...) x = a;
1600 (3) if (...) x = a; // as if with an initial x = x.
1602 The later patterns require jumps to be more expensive.
1604 ??? For future expansion, look for multiple X in such patterns. */
1606 struct noce_if_info if_info
;
1609 rtx orig_x
, x
, a
, b
;
1610 rtx jump
, cond
, insn
;
1612 /* If this is not a standard conditional jump, we can't parse it. */
1613 jump
= test_bb
->end
;
1614 cond
= noce_get_condition (jump
, &if_info
.cond_earliest
);
1618 /* If the conditional jump is more than just a conditional jump,
1619 then we can not do if-conversion on this block. */
1620 if (! onlyjump_p (jump
))
1623 /* We must be comparing objects whose modes imply the size. */
1624 if (GET_MODE (XEXP (cond
, 0)) == BLKmode
)
1627 /* Look for one of the potential sets. */
1628 insn_a
= first_active_insn (then_bb
);
1630 || ! last_active_insn_p (then_bb
, insn_a
)
1631 || (set_a
= single_set (insn_a
)) == NULL_RTX
)
1634 x
= SET_DEST (set_a
);
1635 a
= SET_SRC (set_a
);
1637 /* Look for the other potential set. Make sure we've got equivalent
1639 /* ??? This is overconservative. Storing to two different mems is
1640 as easy as conditionally computing the address. Storing to a
1641 single mem merely requires a scratch memory to use as one of the
1642 destination addresses; often the memory immediately below the
1643 stack pointer is available for this. */
1647 insn_b
= first_active_insn (else_bb
);
1649 || ! last_active_insn_p (else_bb
, insn_b
)
1650 || (set_b
= single_set (insn_b
)) == NULL_RTX
1651 || ! rtx_equal_p (x
, SET_DEST (set_b
)))
1656 insn_b
= prev_nonnote_insn (if_info
.cond_earliest
);
1658 || GET_CODE (insn_b
) != INSN
1659 || (set_b
= single_set (insn_b
)) == NULL_RTX
1660 || ! rtx_equal_p (x
, SET_DEST (set_b
))
1661 || reg_mentioned_p (x
, cond
)
1662 || reg_mentioned_p (x
, a
)
1663 || reg_mentioned_p (x
, SET_SRC (set_b
)))
1664 insn_b
= set_b
= NULL_RTX
;
1666 b
= (set_b
? SET_SRC (set_b
) : x
);
1668 /* X may not be mentioned in the range (cond_earliest, jump]. */
1669 for (insn
= jump
; insn
!= if_info
.cond_earliest
; insn
= PREV_INSN (insn
))
1670 if (INSN_P (insn
) && reg_mentioned_p (x
, insn
))
1673 /* A and B may not be modified in the range [cond_earliest, jump). */
1674 for (insn
= if_info
.cond_earliest
; insn
!= jump
; insn
= NEXT_INSN (insn
))
1676 && (modified_in_p (a
, insn
) || modified_in_p (b
, insn
)))
1679 /* Only operate on register destinations, and even then avoid extending
1680 the lifetime of hard registers on small register class machines. */
1682 if (GET_CODE (x
) != REG
1683 || (SMALL_REGISTER_CLASSES
1684 && REGNO (x
) < FIRST_PSEUDO_REGISTER
))
1688 x
= gen_reg_rtx (GET_MODE (GET_CODE (x
) == STRICT_LOW_PART
1689 ? XEXP (x
, 0) : x
));
1692 /* Don't operate on sources that may trap or are volatile. */
1693 if (! noce_operand_ok (a
) || ! noce_operand_ok (b
))
1696 /* Set up the info block for our subroutines. */
1697 if_info
.test_bb
= test_bb
;
1698 if_info
.cond
= cond
;
1699 if_info
.jump
= jump
;
1700 if_info
.insn_a
= insn_a
;
1701 if_info
.insn_b
= insn_b
;
1706 /* Try optimizations in some approximation of a useful order. */
1707 /* ??? Should first look to see if X is live incoming at all. If it
1708 isn't, we don't need anything but an unconditional set. */
1710 /* Look and see if A and B are really the same. Avoid creating silly
1711 cmove constructs that no one will fix up later. */
1712 if (rtx_equal_p (a
, b
))
1714 /* If we have an INSN_B, we don't have to create any new rtl. Just
1715 move the instruction that we already have. If we don't have an
1716 INSN_B, that means that A == X, and we've got a noop move. In
1717 that case don't do anything and let the code below delete INSN_A. */
1718 if (insn_b
&& else_bb
)
1722 if (else_bb
&& insn_b
== else_bb
->end
)
1723 else_bb
->end
= PREV_INSN (insn_b
);
1724 reorder_insns (insn_b
, insn_b
, PREV_INSN (if_info
.cond_earliest
));
1726 /* If there was a REG_EQUAL note, delete it since it may have been
1727 true due to this insn being after a jump. */
1728 if ((note
= find_reg_note (insn_b
, REG_EQUAL
, NULL_RTX
)) != 0)
1729 remove_note (insn_b
, note
);
1733 /* If we have "x = b; if (...) x = a;", and x has side-effects, then
1734 x must be executed twice. */
1735 else if (insn_b
&& side_effects_p (orig_x
))
1742 if (noce_try_store_flag (&if_info
))
1744 if (noce_try_minmax (&if_info
))
1746 if (noce_try_abs (&if_info
))
1748 if (HAVE_conditional_move
1749 && noce_try_cmove (&if_info
))
1751 if (! HAVE_conditional_execution
)
1753 if (noce_try_store_flag_constants (&if_info
))
1755 if (noce_try_store_flag_inc (&if_info
))
1757 if (noce_try_store_flag_mask (&if_info
))
1759 if (HAVE_conditional_move
1760 && noce_try_cmove_arith (&if_info
))
1767 /* The original sets may now be killed. */
1768 if (insn_a
== then_bb
->end
)
1769 then_bb
->end
= PREV_INSN (insn_a
);
1770 flow_delete_insn (insn_a
);
1772 /* Several special cases here: First, we may have reused insn_b above,
1773 in which case insn_b is now NULL. Second, we want to delete insn_b
1774 if it came from the ELSE block, because follows the now correct
1775 write that appears in the TEST block. However, if we got insn_b from
1776 the TEST block, it may in fact be loading data needed for the comparison.
1777 We'll let life_analysis remove the insn if it's really dead. */
1778 if (insn_b
&& else_bb
)
1780 if (insn_b
== else_bb
->end
)
1781 else_bb
->end
= PREV_INSN (insn_b
);
1782 flow_delete_insn (insn_b
);
1785 /* The new insns will have been inserted before cond_earliest. We should
1786 be able to remove the jump with impunity, but the condition itself may
1787 have been modified by gcse to be shared across basic blocks. */
1788 test_bb
->end
= PREV_INSN (jump
);
1789 flow_delete_insn (jump
);
1791 /* If we used a temporary, fix it up now. */
1795 noce_emit_move_insn (orig_x
, x
);
1796 insn_b
= gen_sequence ();
1799 test_bb
->end
= 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
);
2192 test_bb
->end
= PREV_INSN (jump
);
2193 flow_delete_insn (jump
);
2195 trap_bb
->end
= PREV_INSN (trap
);
2196 flow_delete_insn (trap
);
2198 /* Merge the blocks! */
2199 if (trap_bb
!= then_bb
&& ! else_bb
)
2201 flow_delete_block (trap_bb
);
2202 num_removed_blocks
++;
2204 merge_if_block (test_bb
, then_bb
, else_bb
, join_bb
);
2209 /* Look for IF-THEN-ELSE cases in which one of THEN or ELSE is
2210 transformable, but not necessarily the other. There need be no
2213 Return TRUE if we were successful at converting the the block.
2215 Cases we'd like to look at:
2218 if (test) goto over; // x not live
2226 if (! test) goto label;
2229 if (test) goto E; // x not live
2243 (3) // This one's really only interesting for targets that can do
2244 // multiway branching, e.g. IA-64 BBB bundles. For other targets
2245 // it results in multiple branches on a cache line, which often
2246 // does not sit well with predictors.
2248 if (test1) goto E; // predicted not taken
2264 (A) Don't do (2) if the branch is predicted against the block we're
2265 eliminating. Do it anyway if we can eliminate a branch; this requires
2266 that the sole successor of the eliminated block postdominate the other
2269 (B) With CE, on (3) we can steal from both sides of the if, creating
2278 Again, this is most useful if J postdominates.
2280 (C) CE substitutes for helpful life information.
2282 (D) These heuristics need a lot of work. */
2284 /* Tests for case 1 above. */
2287 find_if_case_1 (test_bb
, then_edge
, else_edge
)
2288 basic_block test_bb
;
2289 edge then_edge
, else_edge
;
2291 basic_block then_bb
= then_edge
->dest
;
2292 basic_block else_bb
= else_edge
->dest
, new_bb
;
2293 edge then_succ
= then_bb
->succ
;
2295 /* THEN has one successor. */
2296 if (!then_succ
|| then_succ
->succ_next
!= NULL
)
2299 /* THEN does not fall through, but is not strange either. */
2300 if (then_succ
->flags
& (EDGE_COMPLEX
| EDGE_FALLTHRU
))
2303 /* THEN has one predecessor. */
2304 if (then_bb
->pred
->pred_next
!= NULL
)
2307 /* THEN must do something. */
2308 if (forwarder_block_p (then_bb
))
2311 num_possible_if_blocks
++;
2313 fprintf (rtl_dump_file
,
2314 "\nIF-CASE-1 found, start %d, then %d\n",
2315 test_bb
->index
, then_bb
->index
);
2317 /* THEN is small. */
2318 if (count_bb_insns (then_bb
) > BRANCH_COST
)
2321 /* Registers set are dead, or are predicable. */
2322 if (! dead_or_predicable (test_bb
, then_bb
, else_bb
,
2323 then_bb
->succ
->dest
, 1))
2326 /* Conversion went ok, including moving the insns and fixing up the
2327 jump. Adjust the CFG to match. */
2329 SET_UPDATE_LIFE (test_bb
);
2330 bitmap_operation (test_bb
->global_live_at_end
,
2331 else_bb
->global_live_at_start
,
2332 then_bb
->global_live_at_end
, BITMAP_IOR
);
2334 new_bb
= redirect_edge_and_branch_force (FALLTHRU_EDGE (test_bb
), else_bb
);
2335 /* Make rest of code believe that the newly created block is the THEN_BB
2336 block we are going to remove. */
2339 new_bb
->aux
= then_bb
->aux
;
2340 SET_UPDATE_LIFE (then_bb
);
2342 flow_delete_block (then_bb
);
2343 /* We've possibly created jump to next insn, cleanup_cfg will solve that
2346 num_removed_blocks
++;
2347 num_updated_if_blocks
++;
2352 /* Test for case 2 above. */
2355 find_if_case_2 (test_bb
, then_edge
, else_edge
)
2356 basic_block test_bb
;
2357 edge then_edge
, else_edge
;
2359 basic_block then_bb
= then_edge
->dest
;
2360 basic_block else_bb
= else_edge
->dest
;
2361 edge else_succ
= else_bb
->succ
;
2364 /* ELSE has one successor. */
2365 if (!else_succ
|| else_succ
->succ_next
!= NULL
)
2368 /* ELSE outgoing edge is not complex. */
2369 if (else_succ
->flags
& EDGE_COMPLEX
)
2372 /* ELSE has one predecessor. */
2373 if (else_bb
->pred
->pred_next
!= NULL
)
2376 /* THEN is not EXIT. */
2377 if (then_bb
->index
< 0)
2380 /* ELSE is predicted or SUCC(ELSE) postdominates THEN. */
2381 note
= find_reg_note (test_bb
->end
, REG_BR_PROB
, NULL_RTX
);
2382 if (note
&& INTVAL (XEXP (note
, 0)) >= REG_BR_PROB_BASE
/ 2)
2384 else if (else_succ
->dest
->index
< 0
2385 || TEST_BIT (post_dominators
[ORIG_INDEX (then_bb
)],
2386 ORIG_INDEX (else_succ
->dest
)))
2391 num_possible_if_blocks
++;
2393 fprintf (rtl_dump_file
,
2394 "\nIF-CASE-2 found, start %d, else %d\n",
2395 test_bb
->index
, else_bb
->index
);
2397 /* ELSE is small. */
2398 if (count_bb_insns (then_bb
) > BRANCH_COST
)
2401 /* Registers set are dead, or are predicable. */
2402 if (! dead_or_predicable (test_bb
, else_bb
, then_bb
, else_succ
->dest
, 0))
2405 /* Conversion went ok, including moving the insns and fixing up the
2406 jump. Adjust the CFG to match. */
2408 SET_UPDATE_LIFE (test_bb
);
2409 bitmap_operation (test_bb
->global_live_at_end
,
2410 then_bb
->global_live_at_start
,
2411 else_bb
->global_live_at_end
, BITMAP_IOR
);
2413 flow_delete_block (else_bb
);
2415 num_removed_blocks
++;
2416 num_updated_if_blocks
++;
2418 /* ??? We may now fallthru from one of THEN's successors into a join
2419 block. Rerun cleanup_cfg? Examine things manually? Wait? */
2424 /* A subroutine of dead_or_predicable called through for_each_rtx.
2425 Return 1 if a memory is found. */
2428 find_memory (px
, data
)
2430 void *data ATTRIBUTE_UNUSED
;
2432 return GET_CODE (*px
) == MEM
;
2435 /* Used by the code above to perform the actual rtl transformations.
2436 Return TRUE if successful.
2438 TEST_BB is the block containing the conditional branch. MERGE_BB
2439 is the block containing the code to manipulate. NEW_DEST is the
2440 label TEST_BB should be branching to after the conversion.
2441 REVERSEP is true if the sense of the branch should be reversed. */
2444 dead_or_predicable (test_bb
, merge_bb
, other_bb
, new_dest
, reversep
)
2445 basic_block test_bb
, merge_bb
, other_bb
;
2446 basic_block new_dest
;
2449 rtx head
, end
, jump
, earliest
, old_dest
, new_label
;
2451 jump
= test_bb
->end
;
2453 /* Find the extent of the real code in the merge block. */
2454 head
= merge_bb
->head
;
2455 end
= merge_bb
->end
;
2457 if (GET_CODE (head
) == CODE_LABEL
)
2458 head
= NEXT_INSN (head
);
2459 if (GET_CODE (head
) == NOTE
)
2463 head
= end
= NULL_RTX
;
2466 head
= NEXT_INSN (head
);
2469 if (GET_CODE (end
) == JUMP_INSN
)
2473 head
= end
= NULL_RTX
;
2476 end
= PREV_INSN (end
);
2479 /* Disable handling dead code by conditional execution if the machine needs
2480 to do anything funny with the tests, etc. */
2481 #ifndef IFCVT_MODIFY_TESTS
2482 if (HAVE_conditional_execution
)
2484 /* In the conditional execution case, we have things easy. We know
2485 the condition is reversable. We don't have to check life info,
2486 becase we're going to conditionally execute the code anyway.
2487 All that's left is making sure the insns involved can actually
2492 cond
= cond_exec_get_condition (jump
);
2496 prob_val
= find_reg_note (jump
, REG_BR_PROB
, NULL_RTX
);
2498 prob_val
= XEXP (prob_val
, 0);
2502 enum rtx_code rev
= reversed_comparison_code (cond
, jump
);
2505 cond
= gen_rtx_fmt_ee (rev
, GET_MODE (cond
), XEXP (cond
, 0),
2508 prob_val
= GEN_INT (REG_BR_PROB_BASE
- INTVAL (prob_val
));
2511 if (! cond_exec_process_insns (head
, end
, cond
, prob_val
, 0))
2519 /* In the non-conditional execution case, we have to verify that there
2520 are no trapping operations, no calls, no references to memory, and
2521 that any registers modified are dead at the branch site. */
2523 rtx insn
, cond
, prev
;
2524 regset_head merge_set_head
, tmp_head
, test_live_head
, test_set_head
;
2525 regset merge_set
, tmp
, test_live
, test_set
;
2526 struct propagate_block_info
*pbi
;
2529 /* Check for no calls or trapping operations. */
2530 for (insn
= head
; ; insn
= NEXT_INSN (insn
))
2532 if (GET_CODE (insn
) == CALL_INSN
)
2536 if (may_trap_p (PATTERN (insn
)))
2539 /* ??? Even non-trapping memories such as stack frame
2540 references must be avoided. For stores, we collect
2541 no lifetime info; for reads, we'd have to assert
2542 true_dependance false against every store in the
2544 if (for_each_rtx (&PATTERN (insn
), find_memory
, NULL
))
2551 if (! any_condjump_p (jump
))
2554 /* Find the extent of the conditional. */
2555 cond
= noce_get_condition (jump
, &earliest
);
2560 MERGE_SET = set of registers set in MERGE_BB
2561 TEST_LIVE = set of registers live at EARLIEST
2562 TEST_SET = set of registers set between EARLIEST and the
2563 end of the block. */
2565 tmp
= INITIALIZE_REG_SET (tmp_head
);
2566 merge_set
= INITIALIZE_REG_SET (merge_set_head
);
2567 test_live
= INITIALIZE_REG_SET (test_live_head
);
2568 test_set
= INITIALIZE_REG_SET (test_set_head
);
2570 /* ??? bb->local_set is only valid during calculate_global_regs_live,
2571 so we must recompute usage for MERGE_BB. Not so bad, I suppose,
2572 since we've already asserted that MERGE_BB is small. */
2573 propagate_block (merge_bb
, tmp
, merge_set
, merge_set
, 0);
2575 /* For small register class machines, don't lengthen lifetimes of
2576 hard registers before reload. */
2577 if (SMALL_REGISTER_CLASSES
&& ! reload_completed
)
2579 EXECUTE_IF_SET_IN_BITMAP
2582 if (i
< FIRST_PSEUDO_REGISTER
2584 && ! global_regs
[i
])
2589 /* For TEST, we're interested in a range of insns, not a whole block.
2590 Moreover, we're interested in the insns live from OTHER_BB. */
2592 COPY_REG_SET (test_live
, other_bb
->global_live_at_start
);
2593 pbi
= init_propagate_block_info (test_bb
, test_live
, test_set
, test_set
,
2596 for (insn
= jump
; ; insn
= prev
)
2598 prev
= propagate_one_insn (pbi
, insn
);
2599 if (insn
== earliest
)
2603 free_propagate_block_info (pbi
);
2605 /* We can perform the transformation if
2606 MERGE_SET & (TEST_SET | TEST_LIVE)
2608 TEST_SET & merge_bb->global_live_at_start
2611 bitmap_operation (tmp
, test_set
, test_live
, BITMAP_IOR
);
2612 bitmap_operation (tmp
, tmp
, merge_set
, BITMAP_AND
);
2613 EXECUTE_IF_SET_IN_BITMAP(tmp
, 0, i
, fail
= 1);
2615 bitmap_operation (tmp
, test_set
, merge_bb
->global_live_at_start
,
2617 EXECUTE_IF_SET_IN_BITMAP(tmp
, 0, i
, fail
= 1);
2620 FREE_REG_SET (merge_set
);
2621 FREE_REG_SET (test_live
);
2622 FREE_REG_SET (test_set
);
2629 /* We don't want to use normal invert_jump or redirect_jump because
2630 we don't want to delete_insn called. Also, we want to do our own
2631 change group management. */
2633 old_dest
= JUMP_LABEL (jump
);
2634 new_label
= block_label (new_dest
);
2636 ? ! invert_jump_1 (jump
, new_label
)
2637 : ! redirect_jump_1 (jump
, new_label
))
2640 if (! apply_change_group ())
2644 LABEL_NUSES (old_dest
) -= 1;
2646 LABEL_NUSES (new_label
) += 1;
2647 JUMP_LABEL (jump
) = new_label
;
2650 invert_br_probabilities (jump
);
2652 redirect_edge_succ (BRANCH_EDGE (test_bb
), new_dest
);
2655 gcov_type count
, probability
;
2656 count
= BRANCH_EDGE (test_bb
)->count
;
2657 BRANCH_EDGE (test_bb
)->count
= FALLTHRU_EDGE (test_bb
)->count
;
2658 FALLTHRU_EDGE (test_bb
)->count
= count
;
2659 probability
= BRANCH_EDGE (test_bb
)->probability
;
2660 BRANCH_EDGE (test_bb
)->probability
= FALLTHRU_EDGE (test_bb
)->probability
;
2661 FALLTHRU_EDGE (test_bb
)->probability
= probability
;
2664 /* Move the insns out of MERGE_BB to before the branch. */
2667 if (end
== merge_bb
->end
)
2668 merge_bb
->end
= PREV_INSN (head
);
2670 squeeze_notes (&head
, &end
);
2672 reorder_insns (head
, end
, PREV_INSN (earliest
));
2681 /* Main entry point for all if-conversion. */
2684 if_convert (x_life_data_ok
)
2689 num_possible_if_blocks
= 0;
2690 num_updated_if_blocks
= 0;
2691 num_removed_blocks
= 0;
2692 life_data_ok
= (x_life_data_ok
!= 0);
2694 /* Free up basic_block_for_insn so that we don't have to keep it
2695 up to date, either here or in merge_blocks_nomove. */
2696 free_basic_block_vars (1);
2698 /* Compute postdominators if we think we'll use them. */
2699 post_dominators
= NULL
;
2700 if (HAVE_conditional_execution
|| life_data_ok
)
2702 post_dominators
= sbitmap_vector_alloc (n_basic_blocks
, n_basic_blocks
);
2703 calculate_dominance_info (NULL
, post_dominators
, CDI_POST_DOMINATORS
);
2706 /* Record initial block numbers. */
2707 for (block_num
= 0; block_num
< n_basic_blocks
; block_num
++)
2708 SET_ORIG_INDEX (BASIC_BLOCK (block_num
), block_num
);
2710 /* Go through each of the basic blocks looking for things to convert. */
2711 for (block_num
= 0; block_num
< n_basic_blocks
; )
2713 basic_block bb
= BASIC_BLOCK (block_num
);
2714 if (find_if_header (bb
))
2715 block_num
= bb
->index
;
2720 if (post_dominators
)
2721 sbitmap_vector_free (post_dominators
);
2724 fflush (rtl_dump_file
);
2726 /* Rebuild basic_block_for_insn for update_life_info and for gcse. */
2727 compute_bb_for_insn (get_max_uid ());
2729 /* Rebuild life info for basic blocks that require it. */
2730 if (num_removed_blocks
&& life_data_ok
)
2732 sbitmap update_life_blocks
= sbitmap_alloc (n_basic_blocks
);
2733 sbitmap_zero (update_life_blocks
);
2735 /* If we allocated new pseudos, we must resize the array for sched1. */
2736 if (max_regno
< max_reg_num ())
2738 max_regno
= max_reg_num ();
2739 allocate_reg_info (max_regno
, FALSE
, FALSE
);
2742 for (block_num
= 0; block_num
< n_basic_blocks
; block_num
++)
2743 if (UPDATE_LIFE (BASIC_BLOCK (block_num
)))
2744 SET_BIT (update_life_blocks
, block_num
);
2746 count_or_remove_death_notes (update_life_blocks
, 1);
2747 /* ??? See about adding a mode that verifies that the initial
2748 set of blocks don't let registers come live. */
2749 update_life_info (update_life_blocks
, UPDATE_LIFE_GLOBAL
,
2750 PROP_DEATH_NOTES
| PROP_SCAN_DEAD_CODE
2751 | PROP_KILL_DEAD_CODE
);
2753 sbitmap_free (update_life_blocks
);
2756 /* Write the final stats. */
2757 if (rtl_dump_file
&& num_possible_if_blocks
> 0)
2759 fprintf (rtl_dump_file
,
2760 "\n%d possible IF blocks searched.\n",
2761 num_possible_if_blocks
);
2762 fprintf (rtl_dump_file
,
2763 "%d IF blocks converted.\n",
2764 num_updated_if_blocks
);
2765 fprintf (rtl_dump_file
,
2766 "%d basic blocks deleted.\n\n\n",
2767 num_removed_blocks
);
2770 #ifdef ENABLE_CHECKING
2771 verify_flow_info ();