tree-ssa-pre.c (my_rev_post_order_compute): Remove set but not used count variable.
[gcc.git] / gcc / tree-ssa-pre.c
1 /* SSA-PRE for trees.
2 Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
3 Free Software Foundation, Inc.
4 Contributed by Daniel Berlin <dan@dberlin.org> and Steven Bosscher
5 <stevenb@suse.de>
6
7 This file is part of GCC.
8
9 GCC is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 3, or (at your option)
12 any later version.
13
14 GCC is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
18
19 You should have received a copy of the GNU General Public License
20 along with GCC; see the file COPYING3. If not see
21 <http://www.gnu.org/licenses/>. */
22
23 #include "config.h"
24 #include "system.h"
25 #include "coretypes.h"
26 #include "tm.h"
27 #include "ggc.h"
28 #include "tree.h"
29 #include "basic-block.h"
30 #include "diagnostic.h"
31 #include "tree-inline.h"
32 #include "tree-flow.h"
33 #include "gimple.h"
34 #include "tree-dump.h"
35 #include "timevar.h"
36 #include "fibheap.h"
37 #include "hashtab.h"
38 #include "tree-iterator.h"
39 #include "real.h"
40 #include "alloc-pool.h"
41 #include "obstack.h"
42 #include "tree-pass.h"
43 #include "flags.h"
44 #include "bitmap.h"
45 #include "langhooks.h"
46 #include "cfgloop.h"
47 #include "tree-ssa-sccvn.h"
48 #include "tree-scalar-evolution.h"
49 #include "params.h"
50 #include "dbgcnt.h"
51
52 /* TODO:
53
54 1. Avail sets can be shared by making an avail_find_leader that
55 walks up the dominator tree and looks in those avail sets.
56 This might affect code optimality, it's unclear right now.
57 2. Strength reduction can be performed by anticipating expressions
58 we can repair later on.
59 3. We can do back-substitution or smarter value numbering to catch
60 commutative expressions split up over multiple statements.
61 */
62
63 /* For ease of terminology, "expression node" in the below refers to
64 every expression node but GIMPLE_ASSIGN, because GIMPLE_ASSIGNs
65 represent the actual statement containing the expressions we care about,
66 and we cache the value number by putting it in the expression. */
67
68 /* Basic algorithm
69
70 First we walk the statements to generate the AVAIL sets, the
71 EXP_GEN sets, and the tmp_gen sets. EXP_GEN sets represent the
72 generation of values/expressions by a given block. We use them
73 when computing the ANTIC sets. The AVAIL sets consist of
74 SSA_NAME's that represent values, so we know what values are
75 available in what blocks. AVAIL is a forward dataflow problem. In
76 SSA, values are never killed, so we don't need a kill set, or a
77 fixpoint iteration, in order to calculate the AVAIL sets. In
78 traditional parlance, AVAIL sets tell us the downsafety of the
79 expressions/values.
80
81 Next, we generate the ANTIC sets. These sets represent the
82 anticipatable expressions. ANTIC is a backwards dataflow
83 problem. An expression is anticipatable in a given block if it could
84 be generated in that block. This means that if we had to perform
85 an insertion in that block, of the value of that expression, we
86 could. Calculating the ANTIC sets requires phi translation of
87 expressions, because the flow goes backwards through phis. We must
88 iterate to a fixpoint of the ANTIC sets, because we have a kill
89 set. Even in SSA form, values are not live over the entire
90 function, only from their definition point onwards. So we have to
91 remove values from the ANTIC set once we go past the definition
92 point of the leaders that make them up.
93 compute_antic/compute_antic_aux performs this computation.
94
95 Third, we perform insertions to make partially redundant
96 expressions fully redundant.
97
98 An expression is partially redundant (excluding partial
99 anticipation) if:
100
101 1. It is AVAIL in some, but not all, of the predecessors of a
102 given block.
103 2. It is ANTIC in all the predecessors.
104
105 In order to make it fully redundant, we insert the expression into
106 the predecessors where it is not available, but is ANTIC.
107
108 For the partial anticipation case, we only perform insertion if it
109 is partially anticipated in some block, and fully available in all
110 of the predecessors.
111
112 insert/insert_aux/do_regular_insertion/do_partial_partial_insertion
113 performs these steps.
114
115 Fourth, we eliminate fully redundant expressions.
116 This is a simple statement walk that replaces redundant
117 calculations with the now available values. */
118
119 /* Representations of value numbers:
120
121 Value numbers are represented by a representative SSA_NAME. We
122 will create fake SSA_NAME's in situations where we need a
123 representative but do not have one (because it is a complex
124 expression). In order to facilitate storing the value numbers in
125 bitmaps, and keep the number of wasted SSA_NAME's down, we also
126 associate a value_id with each value number, and create full blown
127 ssa_name's only where we actually need them (IE in operands of
128 existing expressions).
129
130 Theoretically you could replace all the value_id's with
131 SSA_NAME_VERSION, but this would allocate a large number of
132 SSA_NAME's (which are each > 30 bytes) just to get a 4 byte number.
133 It would also require an additional indirection at each point we
134 use the value id. */
135
136 /* Representation of expressions on value numbers:
137
138 Expressions consisting of value numbers are represented the same
139 way as our VN internally represents them, with an additional
140 "pre_expr" wrapping around them in order to facilitate storing all
141 of the expressions in the same sets. */
142
143 /* Representation of sets:
144
145 The dataflow sets do not need to be sorted in any particular order
146 for the majority of their lifetime, are simply represented as two
147 bitmaps, one that keeps track of values present in the set, and one
148 that keeps track of expressions present in the set.
149
150 When we need them in topological order, we produce it on demand by
151 transforming the bitmap into an array and sorting it into topo
152 order. */
153
154 /* Type of expression, used to know which member of the PRE_EXPR union
155 is valid. */
156
157 enum pre_expr_kind
158 {
159 NAME,
160 NARY,
161 REFERENCE,
162 CONSTANT
163 };
164
165 typedef union pre_expr_union_d
166 {
167 tree name;
168 tree constant;
169 vn_nary_op_t nary;
170 vn_reference_t reference;
171 } pre_expr_union;
172
173 typedef struct pre_expr_d
174 {
175 enum pre_expr_kind kind;
176 unsigned int id;
177 pre_expr_union u;
178 } *pre_expr;
179
180 #define PRE_EXPR_NAME(e) (e)->u.name
181 #define PRE_EXPR_NARY(e) (e)->u.nary
182 #define PRE_EXPR_REFERENCE(e) (e)->u.reference
183 #define PRE_EXPR_CONSTANT(e) (e)->u.constant
184
185 static int
186 pre_expr_eq (const void *p1, const void *p2)
187 {
188 const struct pre_expr_d *e1 = (const struct pre_expr_d *) p1;
189 const struct pre_expr_d *e2 = (const struct pre_expr_d *) p2;
190
191 if (e1->kind != e2->kind)
192 return false;
193
194 switch (e1->kind)
195 {
196 case CONSTANT:
197 return vn_constant_eq_with_type (PRE_EXPR_CONSTANT (e1),
198 PRE_EXPR_CONSTANT (e2));
199 case NAME:
200 return PRE_EXPR_NAME (e1) == PRE_EXPR_NAME (e2);
201 case NARY:
202 return vn_nary_op_eq (PRE_EXPR_NARY (e1), PRE_EXPR_NARY (e2));
203 case REFERENCE:
204 return vn_reference_eq (PRE_EXPR_REFERENCE (e1),
205 PRE_EXPR_REFERENCE (e2));
206 default:
207 gcc_unreachable ();
208 }
209 }
210
211 static hashval_t
212 pre_expr_hash (const void *p1)
213 {
214 const struct pre_expr_d *e = (const struct pre_expr_d *) p1;
215 switch (e->kind)
216 {
217 case CONSTANT:
218 return vn_hash_constant_with_type (PRE_EXPR_CONSTANT (e));
219 case NAME:
220 return SSA_NAME_VERSION (PRE_EXPR_NAME (e));
221 case NARY:
222 return PRE_EXPR_NARY (e)->hashcode;
223 case REFERENCE:
224 return PRE_EXPR_REFERENCE (e)->hashcode;
225 default:
226 gcc_unreachable ();
227 }
228 }
229
230
231 /* Next global expression id number. */
232 static unsigned int next_expression_id;
233
234 /* Mapping from expression to id number we can use in bitmap sets. */
235 DEF_VEC_P (pre_expr);
236 DEF_VEC_ALLOC_P (pre_expr, heap);
237 static VEC(pre_expr, heap) *expressions;
238 static htab_t expression_to_id;
239 static VEC(unsigned, heap) *name_to_id;
240
241 /* Allocate an expression id for EXPR. */
242
243 static inline unsigned int
244 alloc_expression_id (pre_expr expr)
245 {
246 void **slot;
247 /* Make sure we won't overflow. */
248 gcc_assert (next_expression_id + 1 > next_expression_id);
249 expr->id = next_expression_id++;
250 VEC_safe_push (pre_expr, heap, expressions, expr);
251 if (expr->kind == NAME)
252 {
253 unsigned version = SSA_NAME_VERSION (PRE_EXPR_NAME (expr));
254 /* VEC_safe_grow_cleared allocates no headroom. Avoid frequent
255 re-allocations by using VEC_reserve upfront. There is no
256 VEC_quick_grow_cleared unfortunately. */
257 VEC_reserve (unsigned, heap, name_to_id, num_ssa_names);
258 VEC_safe_grow_cleared (unsigned, heap, name_to_id, num_ssa_names);
259 gcc_assert (VEC_index (unsigned, name_to_id, version) == 0);
260 VEC_replace (unsigned, name_to_id, version, expr->id);
261 }
262 else
263 {
264 slot = htab_find_slot (expression_to_id, expr, INSERT);
265 gcc_assert (!*slot);
266 *slot = expr;
267 }
268 return next_expression_id - 1;
269 }
270
271 /* Return the expression id for tree EXPR. */
272
273 static inline unsigned int
274 get_expression_id (const pre_expr expr)
275 {
276 return expr->id;
277 }
278
279 static inline unsigned int
280 lookup_expression_id (const pre_expr expr)
281 {
282 void **slot;
283
284 if (expr->kind == NAME)
285 {
286 unsigned version = SSA_NAME_VERSION (PRE_EXPR_NAME (expr));
287 if (VEC_length (unsigned, name_to_id) <= version)
288 return 0;
289 return VEC_index (unsigned, name_to_id, version);
290 }
291 else
292 {
293 slot = htab_find_slot (expression_to_id, expr, NO_INSERT);
294 if (!slot)
295 return 0;
296 return ((pre_expr)*slot)->id;
297 }
298 }
299
300 /* Return the existing expression id for EXPR, or create one if one
301 does not exist yet. */
302
303 static inline unsigned int
304 get_or_alloc_expression_id (pre_expr expr)
305 {
306 unsigned int id = lookup_expression_id (expr);
307 if (id == 0)
308 return alloc_expression_id (expr);
309 return expr->id = id;
310 }
311
312 /* Return the expression that has expression id ID */
313
314 static inline pre_expr
315 expression_for_id (unsigned int id)
316 {
317 return VEC_index (pre_expr, expressions, id);
318 }
319
320 /* Free the expression id field in all of our expressions,
321 and then destroy the expressions array. */
322
323 static void
324 clear_expression_ids (void)
325 {
326 VEC_free (pre_expr, heap, expressions);
327 }
328
329 static alloc_pool pre_expr_pool;
330
331 /* Given an SSA_NAME NAME, get or create a pre_expr to represent it. */
332
333 static pre_expr
334 get_or_alloc_expr_for_name (tree name)
335 {
336 struct pre_expr_d expr;
337 pre_expr result;
338 unsigned int result_id;
339
340 expr.kind = NAME;
341 expr.id = 0;
342 PRE_EXPR_NAME (&expr) = name;
343 result_id = lookup_expression_id (&expr);
344 if (result_id != 0)
345 return expression_for_id (result_id);
346
347 result = (pre_expr) pool_alloc (pre_expr_pool);
348 result->kind = NAME;
349 PRE_EXPR_NAME (result) = name;
350 alloc_expression_id (result);
351 return result;
352 }
353
354 static bool in_fre = false;
355
356 /* An unordered bitmap set. One bitmap tracks values, the other,
357 expressions. */
358 typedef struct bitmap_set
359 {
360 bitmap expressions;
361 bitmap values;
362 } *bitmap_set_t;
363
364 #define FOR_EACH_EXPR_ID_IN_SET(set, id, bi) \
365 EXECUTE_IF_SET_IN_BITMAP((set)->expressions, 0, (id), (bi))
366
367 #define FOR_EACH_VALUE_ID_IN_SET(set, id, bi) \
368 EXECUTE_IF_SET_IN_BITMAP((set)->values, 0, (id), (bi))
369
370 /* Mapping from value id to expressions with that value_id. */
371 DEF_VEC_P (bitmap_set_t);
372 DEF_VEC_ALLOC_P (bitmap_set_t, heap);
373 static VEC(bitmap_set_t, heap) *value_expressions;
374
375 /* Sets that we need to keep track of. */
376 typedef struct bb_bitmap_sets
377 {
378 /* The EXP_GEN set, which represents expressions/values generated in
379 a basic block. */
380 bitmap_set_t exp_gen;
381
382 /* The PHI_GEN set, which represents PHI results generated in a
383 basic block. */
384 bitmap_set_t phi_gen;
385
386 /* The TMP_GEN set, which represents results/temporaries generated
387 in a basic block. IE the LHS of an expression. */
388 bitmap_set_t tmp_gen;
389
390 /* The AVAIL_OUT set, which represents which values are available in
391 a given basic block. */
392 bitmap_set_t avail_out;
393
394 /* The ANTIC_IN set, which represents which values are anticipatable
395 in a given basic block. */
396 bitmap_set_t antic_in;
397
398 /* The PA_IN set, which represents which values are
399 partially anticipatable in a given basic block. */
400 bitmap_set_t pa_in;
401
402 /* The NEW_SETS set, which is used during insertion to augment the
403 AVAIL_OUT set of blocks with the new insertions performed during
404 the current iteration. */
405 bitmap_set_t new_sets;
406
407 /* A cache for value_dies_in_block_x. */
408 bitmap expr_dies;
409
410 /* True if we have visited this block during ANTIC calculation. */
411 unsigned int visited : 1;
412
413 /* True we have deferred processing this block during ANTIC
414 calculation until its successor is processed. */
415 unsigned int deferred : 1;
416
417 /* True when the block contains a call that might not return. */
418 unsigned int contains_may_not_return_call : 1;
419 } *bb_value_sets_t;
420
421 #define EXP_GEN(BB) ((bb_value_sets_t) ((BB)->aux))->exp_gen
422 #define PHI_GEN(BB) ((bb_value_sets_t) ((BB)->aux))->phi_gen
423 #define TMP_GEN(BB) ((bb_value_sets_t) ((BB)->aux))->tmp_gen
424 #define AVAIL_OUT(BB) ((bb_value_sets_t) ((BB)->aux))->avail_out
425 #define ANTIC_IN(BB) ((bb_value_sets_t) ((BB)->aux))->antic_in
426 #define PA_IN(BB) ((bb_value_sets_t) ((BB)->aux))->pa_in
427 #define NEW_SETS(BB) ((bb_value_sets_t) ((BB)->aux))->new_sets
428 #define EXPR_DIES(BB) ((bb_value_sets_t) ((BB)->aux))->expr_dies
429 #define BB_VISITED(BB) ((bb_value_sets_t) ((BB)->aux))->visited
430 #define BB_DEFERRED(BB) ((bb_value_sets_t) ((BB)->aux))->deferred
431 #define BB_MAY_NOTRETURN(BB) ((bb_value_sets_t) ((BB)->aux))->contains_may_not_return_call
432
433
434 /* Basic block list in postorder. */
435 static int *postorder;
436
437 /* This structure is used to keep track of statistics on what
438 optimization PRE was able to perform. */
439 static struct
440 {
441 /* The number of RHS computations eliminated by PRE. */
442 int eliminations;
443
444 /* The number of new expressions/temporaries generated by PRE. */
445 int insertions;
446
447 /* The number of inserts found due to partial anticipation */
448 int pa_insert;
449
450 /* The number of new PHI nodes added by PRE. */
451 int phis;
452
453 /* The number of values found constant. */
454 int constified;
455
456 } pre_stats;
457
458 static bool do_partial_partial;
459 static pre_expr bitmap_find_leader (bitmap_set_t, unsigned int, gimple);
460 static void bitmap_value_insert_into_set (bitmap_set_t, pre_expr);
461 static void bitmap_value_replace_in_set (bitmap_set_t, pre_expr);
462 static void bitmap_set_copy (bitmap_set_t, bitmap_set_t);
463 static bool bitmap_set_contains_value (bitmap_set_t, unsigned int);
464 static void bitmap_insert_into_set (bitmap_set_t, pre_expr);
465 static void bitmap_insert_into_set_1 (bitmap_set_t, pre_expr,
466 unsigned int, bool);
467 static bitmap_set_t bitmap_set_new (void);
468 static tree create_expression_by_pieces (basic_block, pre_expr, gimple_seq *,
469 gimple, tree);
470 static tree find_or_generate_expression (basic_block, pre_expr, gimple_seq *,
471 gimple);
472 static unsigned int get_expr_value_id (pre_expr);
473
474 /* We can add and remove elements and entries to and from sets
475 and hash tables, so we use alloc pools for them. */
476
477 static alloc_pool bitmap_set_pool;
478 static bitmap_obstack grand_bitmap_obstack;
479
480 /* To avoid adding 300 temporary variables when we only need one, we
481 only create one temporary variable, on demand, and build ssa names
482 off that. We do have to change the variable if the types don't
483 match the current variable's type. */
484 static tree pretemp;
485 static tree storetemp;
486 static tree prephitemp;
487
488 /* Set of blocks with statements that have had its EH information
489 cleaned up. */
490 static bitmap need_eh_cleanup;
491
492 /* The phi_translate_table caches phi translations for a given
493 expression and predecessor. */
494
495 static htab_t phi_translate_table;
496
497 /* A three tuple {e, pred, v} used to cache phi translations in the
498 phi_translate_table. */
499
500 typedef struct expr_pred_trans_d
501 {
502 /* The expression. */
503 pre_expr e;
504
505 /* The predecessor block along which we translated the expression. */
506 basic_block pred;
507
508 /* The value that resulted from the translation. */
509 pre_expr v;
510
511 /* The hashcode for the expression, pred pair. This is cached for
512 speed reasons. */
513 hashval_t hashcode;
514 } *expr_pred_trans_t;
515 typedef const struct expr_pred_trans_d *const_expr_pred_trans_t;
516
517 /* Return the hash value for a phi translation table entry. */
518
519 static hashval_t
520 expr_pred_trans_hash (const void *p)
521 {
522 const_expr_pred_trans_t const ve = (const_expr_pred_trans_t) p;
523 return ve->hashcode;
524 }
525
526 /* Return true if two phi translation table entries are the same.
527 P1 and P2 should point to the expr_pred_trans_t's to be compared.*/
528
529 static int
530 expr_pred_trans_eq (const void *p1, const void *p2)
531 {
532 const_expr_pred_trans_t const ve1 = (const_expr_pred_trans_t) p1;
533 const_expr_pred_trans_t const ve2 = (const_expr_pred_trans_t) p2;
534 basic_block b1 = ve1->pred;
535 basic_block b2 = ve2->pred;
536
537 /* If they are not translations for the same basic block, they can't
538 be equal. */
539 if (b1 != b2)
540 return false;
541 return pre_expr_eq (ve1->e, ve2->e);
542 }
543
544 /* Search in the phi translation table for the translation of
545 expression E in basic block PRED.
546 Return the translated value, if found, NULL otherwise. */
547
548 static inline pre_expr
549 phi_trans_lookup (pre_expr e, basic_block pred)
550 {
551 void **slot;
552 struct expr_pred_trans_d ept;
553
554 ept.e = e;
555 ept.pred = pred;
556 ept.hashcode = iterative_hash_hashval_t (pre_expr_hash (e), pred->index);
557 slot = htab_find_slot_with_hash (phi_translate_table, &ept, ept.hashcode,
558 NO_INSERT);
559 if (!slot)
560 return NULL;
561 else
562 return ((expr_pred_trans_t) *slot)->v;
563 }
564
565
566 /* Add the tuple mapping from {expression E, basic block PRED} to
567 value V, to the phi translation table. */
568
569 static inline void
570 phi_trans_add (pre_expr e, pre_expr v, basic_block pred)
571 {
572 void **slot;
573 expr_pred_trans_t new_pair = XNEW (struct expr_pred_trans_d);
574 new_pair->e = e;
575 new_pair->pred = pred;
576 new_pair->v = v;
577 new_pair->hashcode = iterative_hash_hashval_t (pre_expr_hash (e),
578 pred->index);
579
580 slot = htab_find_slot_with_hash (phi_translate_table, new_pair,
581 new_pair->hashcode, INSERT);
582 if (*slot)
583 free (*slot);
584 *slot = (void *) new_pair;
585 }
586
587
588 /* Add expression E to the expression set of value id V. */
589
590 void
591 add_to_value (unsigned int v, pre_expr e)
592 {
593 bitmap_set_t set;
594
595 gcc_assert (get_expr_value_id (e) == v);
596
597 if (v >= VEC_length (bitmap_set_t, value_expressions))
598 {
599 VEC_safe_grow_cleared (bitmap_set_t, heap, value_expressions,
600 v + 1);
601 }
602
603 set = VEC_index (bitmap_set_t, value_expressions, v);
604 if (!set)
605 {
606 set = bitmap_set_new ();
607 VEC_replace (bitmap_set_t, value_expressions, v, set);
608 }
609
610 bitmap_insert_into_set_1 (set, e, v, true);
611 }
612
613 /* Create a new bitmap set and return it. */
614
615 static bitmap_set_t
616 bitmap_set_new (void)
617 {
618 bitmap_set_t ret = (bitmap_set_t) pool_alloc (bitmap_set_pool);
619 ret->expressions = BITMAP_ALLOC (&grand_bitmap_obstack);
620 ret->values = BITMAP_ALLOC (&grand_bitmap_obstack);
621 return ret;
622 }
623
624 /* Return the value id for a PRE expression EXPR. */
625
626 static unsigned int
627 get_expr_value_id (pre_expr expr)
628 {
629 switch (expr->kind)
630 {
631 case CONSTANT:
632 {
633 unsigned int id;
634 id = get_constant_value_id (PRE_EXPR_CONSTANT (expr));
635 if (id == 0)
636 {
637 id = get_or_alloc_constant_value_id (PRE_EXPR_CONSTANT (expr));
638 add_to_value (id, expr);
639 }
640 return id;
641 }
642 case NAME:
643 return VN_INFO (PRE_EXPR_NAME (expr))->value_id;
644 case NARY:
645 return PRE_EXPR_NARY (expr)->value_id;
646 case REFERENCE:
647 return PRE_EXPR_REFERENCE (expr)->value_id;
648 default:
649 gcc_unreachable ();
650 }
651 }
652
653 /* Remove an expression EXPR from a bitmapped set. */
654
655 static void
656 bitmap_remove_from_set (bitmap_set_t set, pre_expr expr)
657 {
658 unsigned int val = get_expr_value_id (expr);
659 if (!value_id_constant_p (val))
660 {
661 bitmap_clear_bit (set->values, val);
662 bitmap_clear_bit (set->expressions, get_expression_id (expr));
663 }
664 }
665
666 static void
667 bitmap_insert_into_set_1 (bitmap_set_t set, pre_expr expr,
668 unsigned int val, bool allow_constants)
669 {
670 if (allow_constants || !value_id_constant_p (val))
671 {
672 /* We specifically expect this and only this function to be able to
673 insert constants into a set. */
674 bitmap_set_bit (set->values, val);
675 bitmap_set_bit (set->expressions, get_or_alloc_expression_id (expr));
676 }
677 }
678
679 /* Insert an expression EXPR into a bitmapped set. */
680
681 static void
682 bitmap_insert_into_set (bitmap_set_t set, pre_expr expr)
683 {
684 bitmap_insert_into_set_1 (set, expr, get_expr_value_id (expr), false);
685 }
686
687 /* Copy a bitmapped set ORIG, into bitmapped set DEST. */
688
689 static void
690 bitmap_set_copy (bitmap_set_t dest, bitmap_set_t orig)
691 {
692 bitmap_copy (dest->expressions, orig->expressions);
693 bitmap_copy (dest->values, orig->values);
694 }
695
696
697 /* Free memory used up by SET. */
698 static void
699 bitmap_set_free (bitmap_set_t set)
700 {
701 BITMAP_FREE (set->expressions);
702 BITMAP_FREE (set->values);
703 }
704
705
706 /* Generate an topological-ordered array of bitmap set SET. */
707
708 static VEC(pre_expr, heap) *
709 sorted_array_from_bitmap_set (bitmap_set_t set)
710 {
711 unsigned int i, j;
712 bitmap_iterator bi, bj;
713 VEC(pre_expr, heap) *result;
714
715 /* Pre-allocate roughly enough space for the array. */
716 result = VEC_alloc (pre_expr, heap, bitmap_count_bits (set->values));
717
718 FOR_EACH_VALUE_ID_IN_SET (set, i, bi)
719 {
720 /* The number of expressions having a given value is usually
721 relatively small. Thus, rather than making a vector of all
722 the expressions and sorting it by value-id, we walk the values
723 and check in the reverse mapping that tells us what expressions
724 have a given value, to filter those in our set. As a result,
725 the expressions are inserted in value-id order, which means
726 topological order.
727
728 If this is somehow a significant lose for some cases, we can
729 choose which set to walk based on the set size. */
730 bitmap_set_t exprset = VEC_index (bitmap_set_t, value_expressions, i);
731 FOR_EACH_EXPR_ID_IN_SET (exprset, j, bj)
732 {
733 if (bitmap_bit_p (set->expressions, j))
734 VEC_safe_push (pre_expr, heap, result, expression_for_id (j));
735 }
736 }
737
738 return result;
739 }
740
741 /* Perform bitmapped set operation DEST &= ORIG. */
742
743 static void
744 bitmap_set_and (bitmap_set_t dest, bitmap_set_t orig)
745 {
746 bitmap_iterator bi;
747 unsigned int i;
748
749 if (dest != orig)
750 {
751 bitmap temp = BITMAP_ALLOC (&grand_bitmap_obstack);
752
753 bitmap_and_into (dest->values, orig->values);
754 bitmap_copy (temp, dest->expressions);
755 EXECUTE_IF_SET_IN_BITMAP (temp, 0, i, bi)
756 {
757 pre_expr expr = expression_for_id (i);
758 unsigned int value_id = get_expr_value_id (expr);
759 if (!bitmap_bit_p (dest->values, value_id))
760 bitmap_clear_bit (dest->expressions, i);
761 }
762 BITMAP_FREE (temp);
763 }
764 }
765
766 /* Subtract all values and expressions contained in ORIG from DEST. */
767
768 static bitmap_set_t
769 bitmap_set_subtract (bitmap_set_t dest, bitmap_set_t orig)
770 {
771 bitmap_set_t result = bitmap_set_new ();
772 bitmap_iterator bi;
773 unsigned int i;
774
775 bitmap_and_compl (result->expressions, dest->expressions,
776 orig->expressions);
777
778 FOR_EACH_EXPR_ID_IN_SET (result, i, bi)
779 {
780 pre_expr expr = expression_for_id (i);
781 unsigned int value_id = get_expr_value_id (expr);
782 bitmap_set_bit (result->values, value_id);
783 }
784
785 return result;
786 }
787
788 /* Subtract all the values in bitmap set B from bitmap set A. */
789
790 static void
791 bitmap_set_subtract_values (bitmap_set_t a, bitmap_set_t b)
792 {
793 unsigned int i;
794 bitmap_iterator bi;
795 bitmap temp = BITMAP_ALLOC (&grand_bitmap_obstack);
796
797 bitmap_copy (temp, a->expressions);
798 EXECUTE_IF_SET_IN_BITMAP (temp, 0, i, bi)
799 {
800 pre_expr expr = expression_for_id (i);
801 if (bitmap_set_contains_value (b, get_expr_value_id (expr)))
802 bitmap_remove_from_set (a, expr);
803 }
804 BITMAP_FREE (temp);
805 }
806
807
808 /* Return true if bitmapped set SET contains the value VALUE_ID. */
809
810 static bool
811 bitmap_set_contains_value (bitmap_set_t set, unsigned int value_id)
812 {
813 if (value_id_constant_p (value_id))
814 return true;
815
816 if (!set || bitmap_empty_p (set->expressions))
817 return false;
818
819 return bitmap_bit_p (set->values, value_id);
820 }
821
822 static inline bool
823 bitmap_set_contains_expr (bitmap_set_t set, const pre_expr expr)
824 {
825 return bitmap_bit_p (set->expressions, get_expression_id (expr));
826 }
827
828 /* Replace an instance of value LOOKFOR with expression EXPR in SET. */
829
830 static void
831 bitmap_set_replace_value (bitmap_set_t set, unsigned int lookfor,
832 const pre_expr expr)
833 {
834 bitmap_set_t exprset;
835 unsigned int i;
836 bitmap_iterator bi;
837
838 if (value_id_constant_p (lookfor))
839 return;
840
841 if (!bitmap_set_contains_value (set, lookfor))
842 return;
843
844 /* The number of expressions having a given value is usually
845 significantly less than the total number of expressions in SET.
846 Thus, rather than check, for each expression in SET, whether it
847 has the value LOOKFOR, we walk the reverse mapping that tells us
848 what expressions have a given value, and see if any of those
849 expressions are in our set. For large testcases, this is about
850 5-10x faster than walking the bitmap. If this is somehow a
851 significant lose for some cases, we can choose which set to walk
852 based on the set size. */
853 exprset = VEC_index (bitmap_set_t, value_expressions, lookfor);
854 FOR_EACH_EXPR_ID_IN_SET (exprset, i, bi)
855 {
856 if (bitmap_bit_p (set->expressions, i))
857 {
858 bitmap_clear_bit (set->expressions, i);
859 bitmap_set_bit (set->expressions, get_expression_id (expr));
860 return;
861 }
862 }
863 }
864
865 /* Return true if two bitmap sets are equal. */
866
867 static bool
868 bitmap_set_equal (bitmap_set_t a, bitmap_set_t b)
869 {
870 return bitmap_equal_p (a->values, b->values);
871 }
872
873 /* Replace an instance of EXPR's VALUE with EXPR in SET if it exists,
874 and add it otherwise. */
875
876 static void
877 bitmap_value_replace_in_set (bitmap_set_t set, pre_expr expr)
878 {
879 unsigned int val = get_expr_value_id (expr);
880
881 if (bitmap_set_contains_value (set, val))
882 bitmap_set_replace_value (set, val, expr);
883 else
884 bitmap_insert_into_set (set, expr);
885 }
886
887 /* Insert EXPR into SET if EXPR's value is not already present in
888 SET. */
889
890 static void
891 bitmap_value_insert_into_set (bitmap_set_t set, pre_expr expr)
892 {
893 unsigned int val = get_expr_value_id (expr);
894
895 #ifdef ENABLE_CHECKING
896 gcc_assert (expr->id == get_or_alloc_expression_id (expr));
897 #endif
898
899 /* Constant values are always considered to be part of the set. */
900 if (value_id_constant_p (val))
901 return;
902
903 /* If the value membership changed, add the expression. */
904 if (bitmap_set_bit (set->values, val))
905 bitmap_set_bit (set->expressions, expr->id);
906 }
907
908 /* Print out EXPR to outfile. */
909
910 static void
911 print_pre_expr (FILE *outfile, const pre_expr expr)
912 {
913 switch (expr->kind)
914 {
915 case CONSTANT:
916 print_generic_expr (outfile, PRE_EXPR_CONSTANT (expr), 0);
917 break;
918 case NAME:
919 print_generic_expr (outfile, PRE_EXPR_NAME (expr), 0);
920 break;
921 case NARY:
922 {
923 unsigned int i;
924 vn_nary_op_t nary = PRE_EXPR_NARY (expr);
925 fprintf (outfile, "{%s,", tree_code_name [nary->opcode]);
926 for (i = 0; i < nary->length; i++)
927 {
928 print_generic_expr (outfile, nary->op[i], 0);
929 if (i != (unsigned) nary->length - 1)
930 fprintf (outfile, ",");
931 }
932 fprintf (outfile, "}");
933 }
934 break;
935
936 case REFERENCE:
937 {
938 vn_reference_op_t vro;
939 unsigned int i;
940 vn_reference_t ref = PRE_EXPR_REFERENCE (expr);
941 fprintf (outfile, "{");
942 for (i = 0;
943 VEC_iterate (vn_reference_op_s, ref->operands, i, vro);
944 i++)
945 {
946 bool closebrace = false;
947 if (vro->opcode != SSA_NAME
948 && TREE_CODE_CLASS (vro->opcode) != tcc_declaration)
949 {
950 fprintf (outfile, "%s", tree_code_name [vro->opcode]);
951 if (vro->op0)
952 {
953 fprintf (outfile, "<");
954 closebrace = true;
955 }
956 }
957 if (vro->op0)
958 {
959 print_generic_expr (outfile, vro->op0, 0);
960 if (vro->op1)
961 {
962 fprintf (outfile, ",");
963 print_generic_expr (outfile, vro->op1, 0);
964 }
965 if (vro->op2)
966 {
967 fprintf (outfile, ",");
968 print_generic_expr (outfile, vro->op2, 0);
969 }
970 }
971 if (closebrace)
972 fprintf (outfile, ">");
973 if (i != VEC_length (vn_reference_op_s, ref->operands) - 1)
974 fprintf (outfile, ",");
975 }
976 fprintf (outfile, "}");
977 if (ref->vuse)
978 {
979 fprintf (outfile, "@");
980 print_generic_expr (outfile, ref->vuse, 0);
981 }
982 }
983 break;
984 }
985 }
986 void debug_pre_expr (pre_expr);
987
988 /* Like print_pre_expr but always prints to stderr. */
989 void
990 debug_pre_expr (pre_expr e)
991 {
992 print_pre_expr (stderr, e);
993 fprintf (stderr, "\n");
994 }
995
996 /* Print out SET to OUTFILE. */
997
998 static void
999 print_bitmap_set (FILE *outfile, bitmap_set_t set,
1000 const char *setname, int blockindex)
1001 {
1002 fprintf (outfile, "%s[%d] := { ", setname, blockindex);
1003 if (set)
1004 {
1005 bool first = true;
1006 unsigned i;
1007 bitmap_iterator bi;
1008
1009 FOR_EACH_EXPR_ID_IN_SET (set, i, bi)
1010 {
1011 const pre_expr expr = expression_for_id (i);
1012
1013 if (!first)
1014 fprintf (outfile, ", ");
1015 first = false;
1016 print_pre_expr (outfile, expr);
1017
1018 fprintf (outfile, " (%04d)", get_expr_value_id (expr));
1019 }
1020 }
1021 fprintf (outfile, " }\n");
1022 }
1023
1024 void debug_bitmap_set (bitmap_set_t);
1025
1026 void
1027 debug_bitmap_set (bitmap_set_t set)
1028 {
1029 print_bitmap_set (stderr, set, "debug", 0);
1030 }
1031
1032 /* Print out the expressions that have VAL to OUTFILE. */
1033
1034 void
1035 print_value_expressions (FILE *outfile, unsigned int val)
1036 {
1037 bitmap_set_t set = VEC_index (bitmap_set_t, value_expressions, val);
1038 if (set)
1039 {
1040 char s[10];
1041 sprintf (s, "%04d", val);
1042 print_bitmap_set (outfile, set, s, 0);
1043 }
1044 }
1045
1046
1047 void
1048 debug_value_expressions (unsigned int val)
1049 {
1050 print_value_expressions (stderr, val);
1051 }
1052
1053 /* Given a CONSTANT, allocate a new CONSTANT type PRE_EXPR to
1054 represent it. */
1055
1056 static pre_expr
1057 get_or_alloc_expr_for_constant (tree constant)
1058 {
1059 unsigned int result_id;
1060 unsigned int value_id;
1061 struct pre_expr_d expr;
1062 pre_expr newexpr;
1063
1064 expr.kind = CONSTANT;
1065 PRE_EXPR_CONSTANT (&expr) = constant;
1066 result_id = lookup_expression_id (&expr);
1067 if (result_id != 0)
1068 return expression_for_id (result_id);
1069
1070 newexpr = (pre_expr) pool_alloc (pre_expr_pool);
1071 newexpr->kind = CONSTANT;
1072 PRE_EXPR_CONSTANT (newexpr) = constant;
1073 alloc_expression_id (newexpr);
1074 value_id = get_or_alloc_constant_value_id (constant);
1075 add_to_value (value_id, newexpr);
1076 return newexpr;
1077 }
1078
1079 /* Given a value id V, find the actual tree representing the constant
1080 value if there is one, and return it. Return NULL if we can't find
1081 a constant. */
1082
1083 static tree
1084 get_constant_for_value_id (unsigned int v)
1085 {
1086 if (value_id_constant_p (v))
1087 {
1088 unsigned int i;
1089 bitmap_iterator bi;
1090 bitmap_set_t exprset = VEC_index (bitmap_set_t, value_expressions, v);
1091
1092 FOR_EACH_EXPR_ID_IN_SET (exprset, i, bi)
1093 {
1094 pre_expr expr = expression_for_id (i);
1095 if (expr->kind == CONSTANT)
1096 return PRE_EXPR_CONSTANT (expr);
1097 }
1098 }
1099 return NULL;
1100 }
1101
1102 /* Get or allocate a pre_expr for a piece of GIMPLE, and return it.
1103 Currently only supports constants and SSA_NAMES. */
1104 static pre_expr
1105 get_or_alloc_expr_for (tree t)
1106 {
1107 if (TREE_CODE (t) == SSA_NAME)
1108 return get_or_alloc_expr_for_name (t);
1109 else if (is_gimple_min_invariant (t))
1110 return get_or_alloc_expr_for_constant (t);
1111 else
1112 {
1113 /* More complex expressions can result from SCCVN expression
1114 simplification that inserts values for them. As they all
1115 do not have VOPs the get handled by the nary ops struct. */
1116 vn_nary_op_t result;
1117 unsigned int result_id;
1118 vn_nary_op_lookup (t, &result);
1119 if (result != NULL)
1120 {
1121 pre_expr e = (pre_expr) pool_alloc (pre_expr_pool);
1122 e->kind = NARY;
1123 PRE_EXPR_NARY (e) = result;
1124 result_id = lookup_expression_id (e);
1125 if (result_id != 0)
1126 {
1127 pool_free (pre_expr_pool, e);
1128 e = expression_for_id (result_id);
1129 return e;
1130 }
1131 alloc_expression_id (e);
1132 return e;
1133 }
1134 }
1135 return NULL;
1136 }
1137
1138 /* Return the folded version of T if T, when folded, is a gimple
1139 min_invariant. Otherwise, return T. */
1140
1141 static pre_expr
1142 fully_constant_expression (pre_expr e)
1143 {
1144 switch (e->kind)
1145 {
1146 case CONSTANT:
1147 return e;
1148 case NARY:
1149 {
1150 vn_nary_op_t nary = PRE_EXPR_NARY (e);
1151 switch (TREE_CODE_CLASS (nary->opcode))
1152 {
1153 case tcc_expression:
1154 if (nary->opcode == TRUTH_NOT_EXPR)
1155 goto do_unary;
1156 if (nary->opcode != TRUTH_AND_EXPR
1157 && nary->opcode != TRUTH_OR_EXPR
1158 && nary->opcode != TRUTH_XOR_EXPR)
1159 return e;
1160 /* Fallthrough. */
1161 case tcc_binary:
1162 case tcc_comparison:
1163 {
1164 /* We have to go from trees to pre exprs to value ids to
1165 constants. */
1166 tree naryop0 = nary->op[0];
1167 tree naryop1 = nary->op[1];
1168 tree result;
1169 if (!is_gimple_min_invariant (naryop0))
1170 {
1171 pre_expr rep0 = get_or_alloc_expr_for (naryop0);
1172 unsigned int vrep0 = get_expr_value_id (rep0);
1173 tree const0 = get_constant_for_value_id (vrep0);
1174 if (const0)
1175 naryop0 = fold_convert (TREE_TYPE (naryop0), const0);
1176 }
1177 if (!is_gimple_min_invariant (naryop1))
1178 {
1179 pre_expr rep1 = get_or_alloc_expr_for (naryop1);
1180 unsigned int vrep1 = get_expr_value_id (rep1);
1181 tree const1 = get_constant_for_value_id (vrep1);
1182 if (const1)
1183 naryop1 = fold_convert (TREE_TYPE (naryop1), const1);
1184 }
1185 result = fold_binary (nary->opcode, nary->type,
1186 naryop0, naryop1);
1187 if (result && is_gimple_min_invariant (result))
1188 return get_or_alloc_expr_for_constant (result);
1189 /* We might have simplified the expression to a
1190 SSA_NAME for example from x_1 * 1. But we cannot
1191 insert a PHI for x_1 unconditionally as x_1 might
1192 not be available readily. */
1193 return e;
1194 }
1195 case tcc_reference:
1196 if (nary->opcode != REALPART_EXPR
1197 && nary->opcode != IMAGPART_EXPR
1198 && nary->opcode != VIEW_CONVERT_EXPR)
1199 return e;
1200 /* Fallthrough. */
1201 case tcc_unary:
1202 do_unary:
1203 {
1204 /* We have to go from trees to pre exprs to value ids to
1205 constants. */
1206 tree naryop0 = nary->op[0];
1207 tree const0, result;
1208 if (is_gimple_min_invariant (naryop0))
1209 const0 = naryop0;
1210 else
1211 {
1212 pre_expr rep0 = get_or_alloc_expr_for (naryop0);
1213 unsigned int vrep0 = get_expr_value_id (rep0);
1214 const0 = get_constant_for_value_id (vrep0);
1215 }
1216 result = NULL;
1217 if (const0)
1218 {
1219 tree type1 = TREE_TYPE (nary->op[0]);
1220 const0 = fold_convert (type1, const0);
1221 result = fold_unary (nary->opcode, nary->type, const0);
1222 }
1223 if (result && is_gimple_min_invariant (result))
1224 return get_or_alloc_expr_for_constant (result);
1225 return e;
1226 }
1227 default:
1228 return e;
1229 }
1230 }
1231 case REFERENCE:
1232 {
1233 vn_reference_t ref = PRE_EXPR_REFERENCE (e);
1234 tree folded;
1235 if ((folded = fully_constant_vn_reference_p (ref)))
1236 return get_or_alloc_expr_for_constant (folded);
1237 return e;
1238 }
1239 default:
1240 return e;
1241 }
1242 return e;
1243 }
1244
1245 /* Translate the VUSE backwards through phi nodes in PHIBLOCK, so that
1246 it has the value it would have in BLOCK. Set *SAME_VALID to true
1247 in case the new vuse doesn't change the value id of the OPERANDS. */
1248
1249 static tree
1250 translate_vuse_through_block (VEC (vn_reference_op_s, heap) *operands,
1251 alias_set_type set, tree type, tree vuse,
1252 basic_block phiblock,
1253 basic_block block, bool *same_valid)
1254 {
1255 gimple phi = SSA_NAME_DEF_STMT (vuse);
1256 ao_ref ref;
1257 edge e = NULL;
1258 bool use_oracle;
1259
1260 *same_valid = true;
1261
1262 if (gimple_bb (phi) != phiblock)
1263 return vuse;
1264
1265 use_oracle = ao_ref_init_from_vn_reference (&ref, set, type, operands);
1266
1267 /* Use the alias-oracle to find either the PHI node in this block,
1268 the first VUSE used in this block that is equivalent to vuse or
1269 the first VUSE which definition in this block kills the value. */
1270 if (gimple_code (phi) == GIMPLE_PHI)
1271 e = find_edge (block, phiblock);
1272 else if (use_oracle)
1273 while (!stmt_may_clobber_ref_p_1 (phi, &ref))
1274 {
1275 vuse = gimple_vuse (phi);
1276 phi = SSA_NAME_DEF_STMT (vuse);
1277 if (gimple_bb (phi) != phiblock)
1278 return vuse;
1279 if (gimple_code (phi) == GIMPLE_PHI)
1280 {
1281 e = find_edge (block, phiblock);
1282 break;
1283 }
1284 }
1285 else
1286 return NULL_TREE;
1287
1288 if (e)
1289 {
1290 if (use_oracle)
1291 {
1292 bitmap visited = NULL;
1293 /* Try to find a vuse that dominates this phi node by skipping
1294 non-clobbering statements. */
1295 vuse = get_continuation_for_phi (phi, &ref, &visited);
1296 if (visited)
1297 BITMAP_FREE (visited);
1298 }
1299 else
1300 vuse = NULL_TREE;
1301 if (!vuse)
1302 {
1303 /* If we didn't find any, the value ID can't stay the same,
1304 but return the translated vuse. */
1305 *same_valid = false;
1306 vuse = PHI_ARG_DEF (phi, e->dest_idx);
1307 }
1308 /* ??? We would like to return vuse here as this is the canonical
1309 upmost vdef that this reference is associated with. But during
1310 insertion of the references into the hash tables we only ever
1311 directly insert with their direct gimple_vuse, hence returning
1312 something else would make us not find the other expression. */
1313 return PHI_ARG_DEF (phi, e->dest_idx);
1314 }
1315
1316 return NULL_TREE;
1317 }
1318
1319 /* Like bitmap_find_leader, but checks for the value existing in SET1 *or*
1320 SET2. This is used to avoid making a set consisting of the union
1321 of PA_IN and ANTIC_IN during insert. */
1322
1323 static inline pre_expr
1324 find_leader_in_sets (unsigned int val, bitmap_set_t set1, bitmap_set_t set2)
1325 {
1326 pre_expr result;
1327
1328 result = bitmap_find_leader (set1, val, NULL);
1329 if (!result && set2)
1330 result = bitmap_find_leader (set2, val, NULL);
1331 return result;
1332 }
1333
1334 /* Get the tree type for our PRE expression e. */
1335
1336 static tree
1337 get_expr_type (const pre_expr e)
1338 {
1339 switch (e->kind)
1340 {
1341 case NAME:
1342 return TREE_TYPE (PRE_EXPR_NAME (e));
1343 case CONSTANT:
1344 return TREE_TYPE (PRE_EXPR_CONSTANT (e));
1345 case REFERENCE:
1346 return PRE_EXPR_REFERENCE (e)->type;
1347 case NARY:
1348 return PRE_EXPR_NARY (e)->type;
1349 }
1350 gcc_unreachable();
1351 }
1352
1353 /* Get a representative SSA_NAME for a given expression.
1354 Since all of our sub-expressions are treated as values, we require
1355 them to be SSA_NAME's for simplicity.
1356 Prior versions of GVNPRE used to use "value handles" here, so that
1357 an expression would be VH.11 + VH.10 instead of d_3 + e_6. In
1358 either case, the operands are really values (IE we do not expect
1359 them to be usable without finding leaders). */
1360
1361 static tree
1362 get_representative_for (const pre_expr e)
1363 {
1364 tree exprtype;
1365 tree name;
1366 unsigned int value_id = get_expr_value_id (e);
1367
1368 switch (e->kind)
1369 {
1370 case NAME:
1371 return PRE_EXPR_NAME (e);
1372 case CONSTANT:
1373 return PRE_EXPR_CONSTANT (e);
1374 case NARY:
1375 case REFERENCE:
1376 {
1377 /* Go through all of the expressions representing this value
1378 and pick out an SSA_NAME. */
1379 unsigned int i;
1380 bitmap_iterator bi;
1381 bitmap_set_t exprs = VEC_index (bitmap_set_t, value_expressions,
1382 value_id);
1383 FOR_EACH_EXPR_ID_IN_SET (exprs, i, bi)
1384 {
1385 pre_expr rep = expression_for_id (i);
1386 if (rep->kind == NAME)
1387 return PRE_EXPR_NAME (rep);
1388 }
1389 }
1390 break;
1391 }
1392 /* If we reached here we couldn't find an SSA_NAME. This can
1393 happen when we've discovered a value that has never appeared in
1394 the program as set to an SSA_NAME, most likely as the result of
1395 phi translation. */
1396 if (dump_file)
1397 {
1398 fprintf (dump_file,
1399 "Could not find SSA_NAME representative for expression:");
1400 print_pre_expr (dump_file, e);
1401 fprintf (dump_file, "\n");
1402 }
1403
1404 exprtype = get_expr_type (e);
1405
1406 /* Build and insert the assignment of the end result to the temporary
1407 that we will return. */
1408 if (!pretemp || exprtype != TREE_TYPE (pretemp))
1409 {
1410 pretemp = create_tmp_var (exprtype, "pretmp");
1411 get_var_ann (pretemp);
1412 }
1413
1414 name = make_ssa_name (pretemp, gimple_build_nop ());
1415 VN_INFO_GET (name)->value_id = value_id;
1416 if (e->kind == CONSTANT)
1417 VN_INFO (name)->valnum = PRE_EXPR_CONSTANT (e);
1418 else
1419 VN_INFO (name)->valnum = name;
1420
1421 add_to_value (value_id, get_or_alloc_expr_for_name (name));
1422 if (dump_file)
1423 {
1424 fprintf (dump_file, "Created SSA_NAME representative ");
1425 print_generic_expr (dump_file, name, 0);
1426 fprintf (dump_file, " for expression:");
1427 print_pre_expr (dump_file, e);
1428 fprintf (dump_file, "\n");
1429 }
1430
1431 return name;
1432 }
1433
1434
1435
1436 static pre_expr
1437 phi_translate (pre_expr expr, bitmap_set_t set1, bitmap_set_t set2,
1438 basic_block pred, basic_block phiblock);
1439
1440 /* Translate EXPR using phis in PHIBLOCK, so that it has the values of
1441 the phis in PRED. Return NULL if we can't find a leader for each part
1442 of the translated expression. */
1443
1444 static pre_expr
1445 phi_translate_1 (pre_expr expr, bitmap_set_t set1, bitmap_set_t set2,
1446 basic_block pred, basic_block phiblock)
1447 {
1448 switch (expr->kind)
1449 {
1450 case NARY:
1451 {
1452 unsigned int i;
1453 bool changed = false;
1454 vn_nary_op_t nary = PRE_EXPR_NARY (expr);
1455 struct vn_nary_op_s newnary;
1456 /* The NARY structure is only guaranteed to have been
1457 allocated to the nary->length operands. */
1458 memcpy (&newnary, nary, (sizeof (struct vn_nary_op_s)
1459 - sizeof (tree) * (4 - nary->length)));
1460
1461 for (i = 0; i < newnary.length; i++)
1462 {
1463 if (TREE_CODE (newnary.op[i]) != SSA_NAME)
1464 continue;
1465 else
1466 {
1467 pre_expr leader, result;
1468 unsigned int op_val_id = VN_INFO (newnary.op[i])->value_id;
1469 leader = find_leader_in_sets (op_val_id, set1, set2);
1470 result = phi_translate (leader, set1, set2, pred, phiblock);
1471 if (result && result != leader)
1472 {
1473 tree name = get_representative_for (result);
1474 if (!name)
1475 return NULL;
1476 newnary.op[i] = name;
1477 }
1478 else if (!result)
1479 return NULL;
1480
1481 changed |= newnary.op[i] != nary->op[i];
1482 }
1483 }
1484 if (changed)
1485 {
1486 pre_expr constant;
1487 unsigned int new_val_id;
1488
1489 tree result = vn_nary_op_lookup_pieces (newnary.length,
1490 newnary.opcode,
1491 newnary.type,
1492 newnary.op[0],
1493 newnary.op[1],
1494 newnary.op[2],
1495 newnary.op[3],
1496 &nary);
1497 if (result && is_gimple_min_invariant (result))
1498 return get_or_alloc_expr_for_constant (result);
1499
1500 expr = (pre_expr) pool_alloc (pre_expr_pool);
1501 expr->kind = NARY;
1502 expr->id = 0;
1503 if (nary)
1504 {
1505 PRE_EXPR_NARY (expr) = nary;
1506 constant = fully_constant_expression (expr);
1507 if (constant != expr)
1508 return constant;
1509
1510 new_val_id = nary->value_id;
1511 get_or_alloc_expression_id (expr);
1512 }
1513 else
1514 {
1515 new_val_id = get_next_value_id ();
1516 VEC_safe_grow_cleared (bitmap_set_t, heap,
1517 value_expressions,
1518 get_max_value_id() + 1);
1519 nary = vn_nary_op_insert_pieces (newnary.length,
1520 newnary.opcode,
1521 newnary.type,
1522 newnary.op[0],
1523 newnary.op[1],
1524 newnary.op[2],
1525 newnary.op[3],
1526 result, new_val_id);
1527 PRE_EXPR_NARY (expr) = nary;
1528 constant = fully_constant_expression (expr);
1529 if (constant != expr)
1530 return constant;
1531 get_or_alloc_expression_id (expr);
1532 }
1533 add_to_value (new_val_id, expr);
1534 }
1535 return expr;
1536 }
1537 break;
1538
1539 case REFERENCE:
1540 {
1541 vn_reference_t ref = PRE_EXPR_REFERENCE (expr);
1542 VEC (vn_reference_op_s, heap) *operands = ref->operands;
1543 tree vuse = ref->vuse;
1544 tree newvuse = vuse;
1545 VEC (vn_reference_op_s, heap) *newoperands = NULL;
1546 bool changed = false, same_valid = true;
1547 unsigned int i, j;
1548 vn_reference_op_t operand;
1549 vn_reference_t newref;
1550
1551 for (i = 0, j = 0;
1552 VEC_iterate (vn_reference_op_s, operands, i, operand); i++, j++)
1553 {
1554 pre_expr opresult;
1555 pre_expr leader;
1556 tree oldop0 = operand->op0;
1557 tree oldop1 = operand->op1;
1558 tree oldop2 = operand->op2;
1559 tree op0 = oldop0;
1560 tree op1 = oldop1;
1561 tree op2 = oldop2;
1562 tree type = operand->type;
1563 vn_reference_op_s newop = *operand;
1564
1565 if (op0 && TREE_CODE (op0) == SSA_NAME)
1566 {
1567 unsigned int op_val_id = VN_INFO (op0)->value_id;
1568 leader = find_leader_in_sets (op_val_id, set1, set2);
1569 opresult = phi_translate (leader, set1, set2, pred, phiblock);
1570 if (opresult && opresult != leader)
1571 {
1572 tree name = get_representative_for (opresult);
1573 if (!name)
1574 break;
1575 op0 = name;
1576 }
1577 else if (!opresult)
1578 break;
1579 }
1580 changed |= op0 != oldop0;
1581
1582 if (op1 && TREE_CODE (op1) == SSA_NAME)
1583 {
1584 unsigned int op_val_id = VN_INFO (op1)->value_id;
1585 leader = find_leader_in_sets (op_val_id, set1, set2);
1586 opresult = phi_translate (leader, set1, set2, pred, phiblock);
1587 if (opresult && opresult != leader)
1588 {
1589 tree name = get_representative_for (opresult);
1590 if (!name)
1591 break;
1592 op1 = name;
1593 }
1594 else if (!opresult)
1595 break;
1596 }
1597 /* We can't possibly insert these. */
1598 else if (op1 && !is_gimple_min_invariant (op1))
1599 break;
1600 changed |= op1 != oldop1;
1601 if (op2 && TREE_CODE (op2) == SSA_NAME)
1602 {
1603 unsigned int op_val_id = VN_INFO (op2)->value_id;
1604 leader = find_leader_in_sets (op_val_id, set1, set2);
1605 opresult = phi_translate (leader, set1, set2, pred, phiblock);
1606 if (opresult && opresult != leader)
1607 {
1608 tree name = get_representative_for (opresult);
1609 if (!name)
1610 break;
1611 op2 = name;
1612 }
1613 else if (!opresult)
1614 break;
1615 }
1616 /* We can't possibly insert these. */
1617 else if (op2 && !is_gimple_min_invariant (op2))
1618 break;
1619 changed |= op2 != oldop2;
1620
1621 if (!newoperands)
1622 newoperands = VEC_copy (vn_reference_op_s, heap, operands);
1623 /* We may have changed from an SSA_NAME to a constant */
1624 if (newop.opcode == SSA_NAME && TREE_CODE (op0) != SSA_NAME)
1625 newop.opcode = TREE_CODE (op0);
1626 newop.type = type;
1627 newop.op0 = op0;
1628 newop.op1 = op1;
1629 newop.op2 = op2;
1630 VEC_replace (vn_reference_op_s, newoperands, j, &newop);
1631 /* If it transforms from an SSA_NAME to an address, fold with
1632 a preceding indirect reference. */
1633 if (j > 0 && op0 && TREE_CODE (op0) == ADDR_EXPR
1634 && VEC_index (vn_reference_op_s,
1635 newoperands, j - 1)->opcode == INDIRECT_REF)
1636 vn_reference_fold_indirect (&newoperands, &j);
1637 }
1638 if (i != VEC_length (vn_reference_op_s, operands))
1639 {
1640 if (newoperands)
1641 VEC_free (vn_reference_op_s, heap, newoperands);
1642 return NULL;
1643 }
1644
1645 if (vuse)
1646 {
1647 newvuse = translate_vuse_through_block (newoperands,
1648 ref->set, ref->type,
1649 vuse, phiblock, pred,
1650 &same_valid);
1651 if (newvuse == NULL_TREE)
1652 {
1653 VEC_free (vn_reference_op_s, heap, newoperands);
1654 return NULL;
1655 }
1656 }
1657
1658 if (changed || newvuse != vuse)
1659 {
1660 unsigned int new_val_id;
1661 pre_expr constant;
1662
1663 tree result = vn_reference_lookup_pieces (newvuse, ref->set,
1664 ref->type,
1665 newoperands,
1666 &newref, true);
1667 if (result)
1668 VEC_free (vn_reference_op_s, heap, newoperands);
1669
1670 if (result && is_gimple_min_invariant (result))
1671 {
1672 gcc_assert (!newoperands);
1673 return get_or_alloc_expr_for_constant (result);
1674 }
1675
1676 expr = (pre_expr) pool_alloc (pre_expr_pool);
1677 expr->kind = REFERENCE;
1678 expr->id = 0;
1679
1680 if (newref)
1681 {
1682 PRE_EXPR_REFERENCE (expr) = newref;
1683 constant = fully_constant_expression (expr);
1684 if (constant != expr)
1685 return constant;
1686
1687 new_val_id = newref->value_id;
1688 get_or_alloc_expression_id (expr);
1689 }
1690 else
1691 {
1692 if (changed || !same_valid)
1693 {
1694 new_val_id = get_next_value_id ();
1695 VEC_safe_grow_cleared (bitmap_set_t, heap,
1696 value_expressions,
1697 get_max_value_id() + 1);
1698 }
1699 else
1700 new_val_id = ref->value_id;
1701 newref = vn_reference_insert_pieces (newvuse, ref->set,
1702 ref->type,
1703 newoperands,
1704 result, new_val_id);
1705 newoperands = NULL;
1706 PRE_EXPR_REFERENCE (expr) = newref;
1707 constant = fully_constant_expression (expr);
1708 if (constant != expr)
1709 return constant;
1710 get_or_alloc_expression_id (expr);
1711 }
1712 add_to_value (new_val_id, expr);
1713 }
1714 VEC_free (vn_reference_op_s, heap, newoperands);
1715 return expr;
1716 }
1717 break;
1718
1719 case NAME:
1720 {
1721 gimple phi = NULL;
1722 edge e;
1723 gimple def_stmt;
1724 tree name = PRE_EXPR_NAME (expr);
1725
1726 def_stmt = SSA_NAME_DEF_STMT (name);
1727 if (gimple_code (def_stmt) == GIMPLE_PHI
1728 && gimple_bb (def_stmt) == phiblock)
1729 phi = def_stmt;
1730 else
1731 return expr;
1732
1733 e = find_edge (pred, gimple_bb (phi));
1734 if (e)
1735 {
1736 tree def = PHI_ARG_DEF (phi, e->dest_idx);
1737 pre_expr newexpr;
1738
1739 if (TREE_CODE (def) == SSA_NAME)
1740 def = VN_INFO (def)->valnum;
1741
1742 /* Handle constant. */
1743 if (is_gimple_min_invariant (def))
1744 return get_or_alloc_expr_for_constant (def);
1745
1746 if (TREE_CODE (def) == SSA_NAME && ssa_undefined_value_p (def))
1747 return NULL;
1748
1749 newexpr = get_or_alloc_expr_for_name (def);
1750 return newexpr;
1751 }
1752 }
1753 return expr;
1754
1755 default:
1756 gcc_unreachable ();
1757 }
1758 }
1759
1760 /* Wrapper around phi_translate_1 providing caching functionality. */
1761
1762 static pre_expr
1763 phi_translate (pre_expr expr, bitmap_set_t set1, bitmap_set_t set2,
1764 basic_block pred, basic_block phiblock)
1765 {
1766 pre_expr phitrans;
1767
1768 if (!expr)
1769 return NULL;
1770
1771 /* Constants contain no values that need translation. */
1772 if (expr->kind == CONSTANT)
1773 return expr;
1774
1775 if (value_id_constant_p (get_expr_value_id (expr)))
1776 return expr;
1777
1778 if (expr->kind != NAME)
1779 {
1780 phitrans = phi_trans_lookup (expr, pred);
1781 if (phitrans)
1782 return phitrans;
1783 }
1784
1785 /* Translate. */
1786 phitrans = phi_translate_1 (expr, set1, set2, pred, phiblock);
1787
1788 /* Don't add empty translations to the cache. Neither add
1789 translations of NAMEs as those are cheap to translate. */
1790 if (phitrans
1791 && expr->kind != NAME)
1792 phi_trans_add (expr, phitrans, pred);
1793
1794 return phitrans;
1795 }
1796
1797
1798 /* For each expression in SET, translate the values through phi nodes
1799 in PHIBLOCK using edge PHIBLOCK->PRED, and store the resulting
1800 expressions in DEST. */
1801
1802 static void
1803 phi_translate_set (bitmap_set_t dest, bitmap_set_t set, basic_block pred,
1804 basic_block phiblock)
1805 {
1806 VEC (pre_expr, heap) *exprs;
1807 pre_expr expr;
1808 int i;
1809
1810 if (gimple_seq_empty_p (phi_nodes (phiblock)))
1811 {
1812 bitmap_set_copy (dest, set);
1813 return;
1814 }
1815
1816 exprs = sorted_array_from_bitmap_set (set);
1817 for (i = 0; VEC_iterate (pre_expr, exprs, i, expr); i++)
1818 {
1819 pre_expr translated;
1820 translated = phi_translate (expr, set, NULL, pred, phiblock);
1821 if (!translated)
1822 continue;
1823
1824 /* We might end up with multiple expressions from SET being
1825 translated to the same value. In this case we do not want
1826 to retain the NARY or REFERENCE expression but prefer a NAME
1827 which would be the leader. */
1828 if (translated->kind == NAME)
1829 bitmap_value_replace_in_set (dest, translated);
1830 else
1831 bitmap_value_insert_into_set (dest, translated);
1832 }
1833 VEC_free (pre_expr, heap, exprs);
1834 }
1835
1836 /* Find the leader for a value (i.e., the name representing that
1837 value) in a given set, and return it. If STMT is non-NULL it
1838 makes sure the defining statement for the leader dominates it.
1839 Return NULL if no leader is found. */
1840
1841 static pre_expr
1842 bitmap_find_leader (bitmap_set_t set, unsigned int val, gimple stmt)
1843 {
1844 if (value_id_constant_p (val))
1845 {
1846 unsigned int i;
1847 bitmap_iterator bi;
1848 bitmap_set_t exprset = VEC_index (bitmap_set_t, value_expressions, val);
1849
1850 FOR_EACH_EXPR_ID_IN_SET (exprset, i, bi)
1851 {
1852 pre_expr expr = expression_for_id (i);
1853 if (expr->kind == CONSTANT)
1854 return expr;
1855 }
1856 }
1857 if (bitmap_set_contains_value (set, val))
1858 {
1859 /* Rather than walk the entire bitmap of expressions, and see
1860 whether any of them has the value we are looking for, we look
1861 at the reverse mapping, which tells us the set of expressions
1862 that have a given value (IE value->expressions with that
1863 value) and see if any of those expressions are in our set.
1864 The number of expressions per value is usually significantly
1865 less than the number of expressions in the set. In fact, for
1866 large testcases, doing it this way is roughly 5-10x faster
1867 than walking the bitmap.
1868 If this is somehow a significant lose for some cases, we can
1869 choose which set to walk based on which set is smaller. */
1870 unsigned int i;
1871 bitmap_iterator bi;
1872 bitmap_set_t exprset = VEC_index (bitmap_set_t, value_expressions, val);
1873
1874 EXECUTE_IF_AND_IN_BITMAP (exprset->expressions,
1875 set->expressions, 0, i, bi)
1876 {
1877 pre_expr val = expression_for_id (i);
1878 /* At the point where stmt is not null, there should always
1879 be an SSA_NAME first in the list of expressions. */
1880 if (stmt)
1881 {
1882 gimple def_stmt = SSA_NAME_DEF_STMT (PRE_EXPR_NAME (val));
1883 if (gimple_code (def_stmt) != GIMPLE_PHI
1884 && gimple_bb (def_stmt) == gimple_bb (stmt)
1885 && gimple_uid (def_stmt) >= gimple_uid (stmt))
1886 continue;
1887 }
1888 return val;
1889 }
1890 }
1891 return NULL;
1892 }
1893
1894 /* Determine if EXPR, a memory expression, is ANTIC_IN at the top of
1895 BLOCK by seeing if it is not killed in the block. Note that we are
1896 only determining whether there is a store that kills it. Because
1897 of the order in which clean iterates over values, we are guaranteed
1898 that altered operands will have caused us to be eliminated from the
1899 ANTIC_IN set already. */
1900
1901 static bool
1902 value_dies_in_block_x (pre_expr expr, basic_block block)
1903 {
1904 tree vuse = PRE_EXPR_REFERENCE (expr)->vuse;
1905 vn_reference_t refx = PRE_EXPR_REFERENCE (expr);
1906 gimple def;
1907 gimple_stmt_iterator gsi;
1908 unsigned id = get_expression_id (expr);
1909 bool res = false;
1910 ao_ref ref;
1911
1912 if (!vuse)
1913 return false;
1914
1915 /* Lookup a previously calculated result. */
1916 if (EXPR_DIES (block)
1917 && bitmap_bit_p (EXPR_DIES (block), id * 2))
1918 return bitmap_bit_p (EXPR_DIES (block), id * 2 + 1);
1919
1920 /* A memory expression {e, VUSE} dies in the block if there is a
1921 statement that may clobber e. If, starting statement walk from the
1922 top of the basic block, a statement uses VUSE there can be no kill
1923 inbetween that use and the original statement that loaded {e, VUSE},
1924 so we can stop walking. */
1925 ref.base = NULL_TREE;
1926 for (gsi = gsi_start_bb (block); !gsi_end_p (gsi); gsi_next (&gsi))
1927 {
1928 tree def_vuse, def_vdef;
1929 def = gsi_stmt (gsi);
1930 def_vuse = gimple_vuse (def);
1931 def_vdef = gimple_vdef (def);
1932
1933 /* Not a memory statement. */
1934 if (!def_vuse)
1935 continue;
1936
1937 /* Not a may-def. */
1938 if (!def_vdef)
1939 {
1940 /* A load with the same VUSE, we're done. */
1941 if (def_vuse == vuse)
1942 break;
1943
1944 continue;
1945 }
1946
1947 /* Init ref only if we really need it. */
1948 if (ref.base == NULL_TREE
1949 && !ao_ref_init_from_vn_reference (&ref, refx->set, refx->type,
1950 refx->operands))
1951 {
1952 res = true;
1953 break;
1954 }
1955 /* If the statement may clobber expr, it dies. */
1956 if (stmt_may_clobber_ref_p_1 (def, &ref))
1957 {
1958 res = true;
1959 break;
1960 }
1961 }
1962
1963 /* Remember the result. */
1964 if (!EXPR_DIES (block))
1965 EXPR_DIES (block) = BITMAP_ALLOC (&grand_bitmap_obstack);
1966 bitmap_set_bit (EXPR_DIES (block), id * 2);
1967 if (res)
1968 bitmap_set_bit (EXPR_DIES (block), id * 2 + 1);
1969
1970 return res;
1971 }
1972
1973
1974 #define union_contains_value(SET1, SET2, VAL) \
1975 (bitmap_set_contains_value ((SET1), (VAL)) \
1976 || ((SET2) && bitmap_set_contains_value ((SET2), (VAL))))
1977
1978 /* Determine if vn_reference_op_t VRO is legal in SET1 U SET2.
1979 */
1980 static bool
1981 vro_valid_in_sets (bitmap_set_t set1, bitmap_set_t set2,
1982 vn_reference_op_t vro)
1983 {
1984 if (vro->op0 && TREE_CODE (vro->op0) == SSA_NAME)
1985 {
1986 struct pre_expr_d temp;
1987 temp.kind = NAME;
1988 temp.id = 0;
1989 PRE_EXPR_NAME (&temp) = vro->op0;
1990 temp.id = lookup_expression_id (&temp);
1991 if (temp.id == 0)
1992 return false;
1993 if (!union_contains_value (set1, set2,
1994 get_expr_value_id (&temp)))
1995 return false;
1996 }
1997 if (vro->op1 && TREE_CODE (vro->op1) == SSA_NAME)
1998 {
1999 struct pre_expr_d temp;
2000 temp.kind = NAME;
2001 temp.id = 0;
2002 PRE_EXPR_NAME (&temp) = vro->op1;
2003 temp.id = lookup_expression_id (&temp);
2004 if (temp.id == 0)
2005 return false;
2006 if (!union_contains_value (set1, set2,
2007 get_expr_value_id (&temp)))
2008 return false;
2009 }
2010
2011 if (vro->op2 && TREE_CODE (vro->op2) == SSA_NAME)
2012 {
2013 struct pre_expr_d temp;
2014 temp.kind = NAME;
2015 temp.id = 0;
2016 PRE_EXPR_NAME (&temp) = vro->op2;
2017 temp.id = lookup_expression_id (&temp);
2018 if (temp.id == 0)
2019 return false;
2020 if (!union_contains_value (set1, set2,
2021 get_expr_value_id (&temp)))
2022 return false;
2023 }
2024
2025 return true;
2026 }
2027
2028 /* Determine if the expression EXPR is valid in SET1 U SET2.
2029 ONLY SET2 CAN BE NULL.
2030 This means that we have a leader for each part of the expression
2031 (if it consists of values), or the expression is an SSA_NAME.
2032 For loads/calls, we also see if the vuse is killed in this block. */
2033
2034 static bool
2035 valid_in_sets (bitmap_set_t set1, bitmap_set_t set2, pre_expr expr,
2036 basic_block block)
2037 {
2038 switch (expr->kind)
2039 {
2040 case NAME:
2041 return bitmap_set_contains_expr (AVAIL_OUT (block), expr);
2042 case NARY:
2043 {
2044 unsigned int i;
2045 vn_nary_op_t nary = PRE_EXPR_NARY (expr);
2046 for (i = 0; i < nary->length; i++)
2047 {
2048 if (TREE_CODE (nary->op[i]) == SSA_NAME)
2049 {
2050 struct pre_expr_d temp;
2051 temp.kind = NAME;
2052 temp.id = 0;
2053 PRE_EXPR_NAME (&temp) = nary->op[i];
2054 temp.id = lookup_expression_id (&temp);
2055 if (temp.id == 0)
2056 return false;
2057 if (!union_contains_value (set1, set2,
2058 get_expr_value_id (&temp)))
2059 return false;
2060 }
2061 }
2062 /* If the NARY may trap make sure the block does not contain
2063 a possible exit point.
2064 ??? This is overly conservative if we translate AVAIL_OUT
2065 as the available expression might be after the exit point. */
2066 if (BB_MAY_NOTRETURN (block)
2067 && vn_nary_may_trap (nary))
2068 return false;
2069 return true;
2070 }
2071 break;
2072 case REFERENCE:
2073 {
2074 vn_reference_t ref = PRE_EXPR_REFERENCE (expr);
2075 vn_reference_op_t vro;
2076 unsigned int i;
2077
2078 for (i = 0; VEC_iterate (vn_reference_op_s, ref->operands, i, vro); i++)
2079 {
2080 if (!vro_valid_in_sets (set1, set2, vro))
2081 return false;
2082 }
2083 if (ref->vuse)
2084 {
2085 gimple def_stmt = SSA_NAME_DEF_STMT (ref->vuse);
2086 if (!gimple_nop_p (def_stmt)
2087 && gimple_bb (def_stmt) != block
2088 && !dominated_by_p (CDI_DOMINATORS,
2089 block, gimple_bb (def_stmt)))
2090 return false;
2091 }
2092 return !value_dies_in_block_x (expr, block);
2093 }
2094 default:
2095 gcc_unreachable ();
2096 }
2097 }
2098
2099 /* Clean the set of expressions that are no longer valid in SET1 or
2100 SET2. This means expressions that are made up of values we have no
2101 leaders for in SET1 or SET2. This version is used for partial
2102 anticipation, which means it is not valid in either ANTIC_IN or
2103 PA_IN. */
2104
2105 static void
2106 dependent_clean (bitmap_set_t set1, bitmap_set_t set2, basic_block block)
2107 {
2108 VEC (pre_expr, heap) *exprs = sorted_array_from_bitmap_set (set1);
2109 pre_expr expr;
2110 int i;
2111
2112 for (i = 0; VEC_iterate (pre_expr, exprs, i, expr); i++)
2113 {
2114 if (!valid_in_sets (set1, set2, expr, block))
2115 bitmap_remove_from_set (set1, expr);
2116 }
2117 VEC_free (pre_expr, heap, exprs);
2118 }
2119
2120 /* Clean the set of expressions that are no longer valid in SET. This
2121 means expressions that are made up of values we have no leaders for
2122 in SET. */
2123
2124 static void
2125 clean (bitmap_set_t set, basic_block block)
2126 {
2127 VEC (pre_expr, heap) *exprs = sorted_array_from_bitmap_set (set);
2128 pre_expr expr;
2129 int i;
2130
2131 for (i = 0; VEC_iterate (pre_expr, exprs, i, expr); i++)
2132 {
2133 if (!valid_in_sets (set, NULL, expr, block))
2134 bitmap_remove_from_set (set, expr);
2135 }
2136 VEC_free (pre_expr, heap, exprs);
2137 }
2138
2139 static sbitmap has_abnormal_preds;
2140
2141 /* List of blocks that may have changed during ANTIC computation and
2142 thus need to be iterated over. */
2143
2144 static sbitmap changed_blocks;
2145
2146 /* Decide whether to defer a block for a later iteration, or PHI
2147 translate SOURCE to DEST using phis in PHIBLOCK. Return false if we
2148 should defer the block, and true if we processed it. */
2149
2150 static bool
2151 defer_or_phi_translate_block (bitmap_set_t dest, bitmap_set_t source,
2152 basic_block block, basic_block phiblock)
2153 {
2154 if (!BB_VISITED (phiblock))
2155 {
2156 SET_BIT (changed_blocks, block->index);
2157 BB_VISITED (block) = 0;
2158 BB_DEFERRED (block) = 1;
2159 return false;
2160 }
2161 else
2162 phi_translate_set (dest, source, block, phiblock);
2163 return true;
2164 }
2165
2166 /* Compute the ANTIC set for BLOCK.
2167
2168 If succs(BLOCK) > 1 then
2169 ANTIC_OUT[BLOCK] = intersection of ANTIC_IN[b] for all succ(BLOCK)
2170 else if succs(BLOCK) == 1 then
2171 ANTIC_OUT[BLOCK] = phi_translate (ANTIC_IN[succ(BLOCK)])
2172
2173 ANTIC_IN[BLOCK] = clean(ANTIC_OUT[BLOCK] U EXP_GEN[BLOCK] - TMP_GEN[BLOCK])
2174 */
2175
2176 static bool
2177 compute_antic_aux (basic_block block, bool block_has_abnormal_pred_edge)
2178 {
2179 bool changed = false;
2180 bitmap_set_t S, old, ANTIC_OUT;
2181 bitmap_iterator bi;
2182 unsigned int bii;
2183 edge e;
2184 edge_iterator ei;
2185
2186 old = ANTIC_OUT = S = NULL;
2187 BB_VISITED (block) = 1;
2188
2189 /* If any edges from predecessors are abnormal, antic_in is empty,
2190 so do nothing. */
2191 if (block_has_abnormal_pred_edge)
2192 goto maybe_dump_sets;
2193
2194 old = ANTIC_IN (block);
2195 ANTIC_OUT = bitmap_set_new ();
2196
2197 /* If the block has no successors, ANTIC_OUT is empty. */
2198 if (EDGE_COUNT (block->succs) == 0)
2199 ;
2200 /* If we have one successor, we could have some phi nodes to
2201 translate through. */
2202 else if (single_succ_p (block))
2203 {
2204 basic_block succ_bb = single_succ (block);
2205
2206 /* We trade iterations of the dataflow equations for having to
2207 phi translate the maximal set, which is incredibly slow
2208 (since the maximal set often has 300+ members, even when you
2209 have a small number of blocks).
2210 Basically, we defer the computation of ANTIC for this block
2211 until we have processed it's successor, which will inevitably
2212 have a *much* smaller set of values to phi translate once
2213 clean has been run on it.
2214 The cost of doing this is that we technically perform more
2215 iterations, however, they are lower cost iterations.
2216
2217 Timings for PRE on tramp3d-v4:
2218 without maximal set fix: 11 seconds
2219 with maximal set fix/without deferring: 26 seconds
2220 with maximal set fix/with deferring: 11 seconds
2221 */
2222
2223 if (!defer_or_phi_translate_block (ANTIC_OUT, ANTIC_IN (succ_bb),
2224 block, succ_bb))
2225 {
2226 changed = true;
2227 goto maybe_dump_sets;
2228 }
2229 }
2230 /* If we have multiple successors, we take the intersection of all of
2231 them. Note that in the case of loop exit phi nodes, we may have
2232 phis to translate through. */
2233 else
2234 {
2235 VEC(basic_block, heap) * worklist;
2236 size_t i;
2237 basic_block bprime, first = NULL;
2238
2239 worklist = VEC_alloc (basic_block, heap, EDGE_COUNT (block->succs));
2240 FOR_EACH_EDGE (e, ei, block->succs)
2241 {
2242 if (!first
2243 && BB_VISITED (e->dest))
2244 first = e->dest;
2245 else if (BB_VISITED (e->dest))
2246 VEC_quick_push (basic_block, worklist, e->dest);
2247 }
2248
2249 /* Of multiple successors we have to have visited one already. */
2250 if (!first)
2251 {
2252 SET_BIT (changed_blocks, block->index);
2253 BB_VISITED (block) = 0;
2254 BB_DEFERRED (block) = 1;
2255 changed = true;
2256 VEC_free (basic_block, heap, worklist);
2257 goto maybe_dump_sets;
2258 }
2259
2260 if (!gimple_seq_empty_p (phi_nodes (first)))
2261 phi_translate_set (ANTIC_OUT, ANTIC_IN (first), block, first);
2262 else
2263 bitmap_set_copy (ANTIC_OUT, ANTIC_IN (first));
2264
2265 for (i = 0; VEC_iterate (basic_block, worklist, i, bprime); i++)
2266 {
2267 if (!gimple_seq_empty_p (phi_nodes (bprime)))
2268 {
2269 bitmap_set_t tmp = bitmap_set_new ();
2270 phi_translate_set (tmp, ANTIC_IN (bprime), block, bprime);
2271 bitmap_set_and (ANTIC_OUT, tmp);
2272 bitmap_set_free (tmp);
2273 }
2274 else
2275 bitmap_set_and (ANTIC_OUT, ANTIC_IN (bprime));
2276 }
2277 VEC_free (basic_block, heap, worklist);
2278 }
2279
2280 /* Generate ANTIC_OUT - TMP_GEN. */
2281 S = bitmap_set_subtract (ANTIC_OUT, TMP_GEN (block));
2282
2283 /* Start ANTIC_IN with EXP_GEN - TMP_GEN. */
2284 ANTIC_IN (block) = bitmap_set_subtract (EXP_GEN (block),
2285 TMP_GEN (block));
2286
2287 /* Then union in the ANTIC_OUT - TMP_GEN values,
2288 to get ANTIC_OUT U EXP_GEN - TMP_GEN */
2289 FOR_EACH_EXPR_ID_IN_SET (S, bii, bi)
2290 bitmap_value_insert_into_set (ANTIC_IN (block),
2291 expression_for_id (bii));
2292
2293 clean (ANTIC_IN (block), block);
2294
2295 /* !old->expressions can happen when we deferred a block. */
2296 if (!old->expressions || !bitmap_set_equal (old, ANTIC_IN (block)))
2297 {
2298 changed = true;
2299 SET_BIT (changed_blocks, block->index);
2300 FOR_EACH_EDGE (e, ei, block->preds)
2301 SET_BIT (changed_blocks, e->src->index);
2302 }
2303 else
2304 RESET_BIT (changed_blocks, block->index);
2305
2306 maybe_dump_sets:
2307 if (dump_file && (dump_flags & TDF_DETAILS))
2308 {
2309 if (!BB_DEFERRED (block) || BB_VISITED (block))
2310 {
2311 if (ANTIC_OUT)
2312 print_bitmap_set (dump_file, ANTIC_OUT, "ANTIC_OUT", block->index);
2313
2314 print_bitmap_set (dump_file, ANTIC_IN (block), "ANTIC_IN",
2315 block->index);
2316
2317 if (S)
2318 print_bitmap_set (dump_file, S, "S", block->index);
2319 }
2320 else
2321 {
2322 fprintf (dump_file,
2323 "Block %d was deferred for a future iteration.\n",
2324 block->index);
2325 }
2326 }
2327 if (old)
2328 bitmap_set_free (old);
2329 if (S)
2330 bitmap_set_free (S);
2331 if (ANTIC_OUT)
2332 bitmap_set_free (ANTIC_OUT);
2333 return changed;
2334 }
2335
2336 /* Compute PARTIAL_ANTIC for BLOCK.
2337
2338 If succs(BLOCK) > 1 then
2339 PA_OUT[BLOCK] = value wise union of PA_IN[b] + all ANTIC_IN not
2340 in ANTIC_OUT for all succ(BLOCK)
2341 else if succs(BLOCK) == 1 then
2342 PA_OUT[BLOCK] = phi_translate (PA_IN[succ(BLOCK)])
2343
2344 PA_IN[BLOCK] = dependent_clean(PA_OUT[BLOCK] - TMP_GEN[BLOCK]
2345 - ANTIC_IN[BLOCK])
2346
2347 */
2348 static bool
2349 compute_partial_antic_aux (basic_block block,
2350 bool block_has_abnormal_pred_edge)
2351 {
2352 bool changed = false;
2353 bitmap_set_t old_PA_IN;
2354 bitmap_set_t PA_OUT;
2355 edge e;
2356 edge_iterator ei;
2357 unsigned long max_pa = PARAM_VALUE (PARAM_MAX_PARTIAL_ANTIC_LENGTH);
2358
2359 old_PA_IN = PA_OUT = NULL;
2360
2361 /* If any edges from predecessors are abnormal, antic_in is empty,
2362 so do nothing. */
2363 if (block_has_abnormal_pred_edge)
2364 goto maybe_dump_sets;
2365
2366 /* If there are too many partially anticipatable values in the
2367 block, phi_translate_set can take an exponential time: stop
2368 before the translation starts. */
2369 if (max_pa
2370 && single_succ_p (block)
2371 && bitmap_count_bits (PA_IN (single_succ (block))->values) > max_pa)
2372 goto maybe_dump_sets;
2373
2374 old_PA_IN = PA_IN (block);
2375 PA_OUT = bitmap_set_new ();
2376
2377 /* If the block has no successors, ANTIC_OUT is empty. */
2378 if (EDGE_COUNT (block->succs) == 0)
2379 ;
2380 /* If we have one successor, we could have some phi nodes to
2381 translate through. Note that we can't phi translate across DFS
2382 back edges in partial antic, because it uses a union operation on
2383 the successors. For recurrences like IV's, we will end up
2384 generating a new value in the set on each go around (i + 3 (VH.1)
2385 VH.1 + 1 (VH.2), VH.2 + 1 (VH.3), etc), forever. */
2386 else if (single_succ_p (block))
2387 {
2388 basic_block succ = single_succ (block);
2389 if (!(single_succ_edge (block)->flags & EDGE_DFS_BACK))
2390 phi_translate_set (PA_OUT, PA_IN (succ), block, succ);
2391 }
2392 /* If we have multiple successors, we take the union of all of
2393 them. */
2394 else
2395 {
2396 VEC(basic_block, heap) * worklist;
2397 size_t i;
2398 basic_block bprime;
2399
2400 worklist = VEC_alloc (basic_block, heap, EDGE_COUNT (block->succs));
2401 FOR_EACH_EDGE (e, ei, block->succs)
2402 {
2403 if (e->flags & EDGE_DFS_BACK)
2404 continue;
2405 VEC_quick_push (basic_block, worklist, e->dest);
2406 }
2407 if (VEC_length (basic_block, worklist) > 0)
2408 {
2409 for (i = 0; VEC_iterate (basic_block, worklist, i, bprime); i++)
2410 {
2411 unsigned int i;
2412 bitmap_iterator bi;
2413
2414 FOR_EACH_EXPR_ID_IN_SET (ANTIC_IN (bprime), i, bi)
2415 bitmap_value_insert_into_set (PA_OUT,
2416 expression_for_id (i));
2417 if (!gimple_seq_empty_p (phi_nodes (bprime)))
2418 {
2419 bitmap_set_t pa_in = bitmap_set_new ();
2420 phi_translate_set (pa_in, PA_IN (bprime), block, bprime);
2421 FOR_EACH_EXPR_ID_IN_SET (pa_in, i, bi)
2422 bitmap_value_insert_into_set (PA_OUT,
2423 expression_for_id (i));
2424 bitmap_set_free (pa_in);
2425 }
2426 else
2427 FOR_EACH_EXPR_ID_IN_SET (PA_IN (bprime), i, bi)
2428 bitmap_value_insert_into_set (PA_OUT,
2429 expression_for_id (i));
2430 }
2431 }
2432 VEC_free (basic_block, heap, worklist);
2433 }
2434
2435 /* PA_IN starts with PA_OUT - TMP_GEN.
2436 Then we subtract things from ANTIC_IN. */
2437 PA_IN (block) = bitmap_set_subtract (PA_OUT, TMP_GEN (block));
2438
2439 /* For partial antic, we want to put back in the phi results, since
2440 we will properly avoid making them partially antic over backedges. */
2441 bitmap_ior_into (PA_IN (block)->values, PHI_GEN (block)->values);
2442 bitmap_ior_into (PA_IN (block)->expressions, PHI_GEN (block)->expressions);
2443
2444 /* PA_IN[block] = PA_IN[block] - ANTIC_IN[block] */
2445 bitmap_set_subtract_values (PA_IN (block), ANTIC_IN (block));
2446
2447 dependent_clean (PA_IN (block), ANTIC_IN (block), block);
2448
2449 if (!bitmap_set_equal (old_PA_IN, PA_IN (block)))
2450 {
2451 changed = true;
2452 SET_BIT (changed_blocks, block->index);
2453 FOR_EACH_EDGE (e, ei, block->preds)
2454 SET_BIT (changed_blocks, e->src->index);
2455 }
2456 else
2457 RESET_BIT (changed_blocks, block->index);
2458
2459 maybe_dump_sets:
2460 if (dump_file && (dump_flags & TDF_DETAILS))
2461 {
2462 if (PA_OUT)
2463 print_bitmap_set (dump_file, PA_OUT, "PA_OUT", block->index);
2464
2465 print_bitmap_set (dump_file, PA_IN (block), "PA_IN", block->index);
2466 }
2467 if (old_PA_IN)
2468 bitmap_set_free (old_PA_IN);
2469 if (PA_OUT)
2470 bitmap_set_free (PA_OUT);
2471 return changed;
2472 }
2473
2474 /* Compute ANTIC and partial ANTIC sets. */
2475
2476 static void
2477 compute_antic (void)
2478 {
2479 bool changed = true;
2480 int num_iterations = 0;
2481 basic_block block;
2482 int i;
2483
2484 /* If any predecessor edges are abnormal, we punt, so antic_in is empty.
2485 We pre-build the map of blocks with incoming abnormal edges here. */
2486 has_abnormal_preds = sbitmap_alloc (last_basic_block);
2487 sbitmap_zero (has_abnormal_preds);
2488
2489 FOR_EACH_BB (block)
2490 {
2491 edge_iterator ei;
2492 edge e;
2493
2494 FOR_EACH_EDGE (e, ei, block->preds)
2495 {
2496 e->flags &= ~EDGE_DFS_BACK;
2497 if (e->flags & EDGE_ABNORMAL)
2498 {
2499 SET_BIT (has_abnormal_preds, block->index);
2500 break;
2501 }
2502 }
2503
2504 BB_VISITED (block) = 0;
2505 BB_DEFERRED (block) = 0;
2506
2507 /* While we are here, give empty ANTIC_IN sets to each block. */
2508 ANTIC_IN (block) = bitmap_set_new ();
2509 PA_IN (block) = bitmap_set_new ();
2510 }
2511
2512 /* At the exit block we anticipate nothing. */
2513 ANTIC_IN (EXIT_BLOCK_PTR) = bitmap_set_new ();
2514 BB_VISITED (EXIT_BLOCK_PTR) = 1;
2515 PA_IN (EXIT_BLOCK_PTR) = bitmap_set_new ();
2516
2517 changed_blocks = sbitmap_alloc (last_basic_block + 1);
2518 sbitmap_ones (changed_blocks);
2519 while (changed)
2520 {
2521 if (dump_file && (dump_flags & TDF_DETAILS))
2522 fprintf (dump_file, "Starting iteration %d\n", num_iterations);
2523 num_iterations++;
2524 changed = false;
2525 for (i = n_basic_blocks - NUM_FIXED_BLOCKS - 1; i >= 0; i--)
2526 {
2527 if (TEST_BIT (changed_blocks, postorder[i]))
2528 {
2529 basic_block block = BASIC_BLOCK (postorder[i]);
2530 changed |= compute_antic_aux (block,
2531 TEST_BIT (has_abnormal_preds,
2532 block->index));
2533 }
2534 }
2535 #ifdef ENABLE_CHECKING
2536 /* Theoretically possible, but *highly* unlikely. */
2537 gcc_assert (num_iterations < 500);
2538 #endif
2539 }
2540
2541 statistics_histogram_event (cfun, "compute_antic iterations",
2542 num_iterations);
2543
2544 if (do_partial_partial)
2545 {
2546 sbitmap_ones (changed_blocks);
2547 mark_dfs_back_edges ();
2548 num_iterations = 0;
2549 changed = true;
2550 while (changed)
2551 {
2552 if (dump_file && (dump_flags & TDF_DETAILS))
2553 fprintf (dump_file, "Starting iteration %d\n", num_iterations);
2554 num_iterations++;
2555 changed = false;
2556 for (i = n_basic_blocks - NUM_FIXED_BLOCKS - 1 ; i >= 0; i--)
2557 {
2558 if (TEST_BIT (changed_blocks, postorder[i]))
2559 {
2560 basic_block block = BASIC_BLOCK (postorder[i]);
2561 changed
2562 |= compute_partial_antic_aux (block,
2563 TEST_BIT (has_abnormal_preds,
2564 block->index));
2565 }
2566 }
2567 #ifdef ENABLE_CHECKING
2568 /* Theoretically possible, but *highly* unlikely. */
2569 gcc_assert (num_iterations < 500);
2570 #endif
2571 }
2572 statistics_histogram_event (cfun, "compute_partial_antic iterations",
2573 num_iterations);
2574 }
2575 sbitmap_free (has_abnormal_preds);
2576 sbitmap_free (changed_blocks);
2577 }
2578
2579 /* Return true if we can value number the call in STMT. This is true
2580 if we have a pure or constant call. */
2581
2582 static bool
2583 can_value_number_call (gimple stmt)
2584 {
2585 if (gimple_call_flags (stmt) & (ECF_PURE | ECF_CONST))
2586 return true;
2587 return false;
2588 }
2589
2590 /* Return true if OP is a tree which we can perform PRE on.
2591 This may not match the operations we can value number, but in
2592 a perfect world would. */
2593
2594 static bool
2595 can_PRE_operation (tree op)
2596 {
2597 return UNARY_CLASS_P (op)
2598 || BINARY_CLASS_P (op)
2599 || COMPARISON_CLASS_P (op)
2600 || TREE_CODE (op) == INDIRECT_REF
2601 || TREE_CODE (op) == COMPONENT_REF
2602 || TREE_CODE (op) == VIEW_CONVERT_EXPR
2603 || TREE_CODE (op) == CALL_EXPR
2604 || TREE_CODE (op) == ARRAY_REF;
2605 }
2606
2607
2608 /* Inserted expressions are placed onto this worklist, which is used
2609 for performing quick dead code elimination of insertions we made
2610 that didn't turn out to be necessary. */
2611 static VEC(gimple,heap) *inserted_exprs;
2612 static bitmap inserted_phi_names;
2613
2614 /* Pool allocated fake store expressions are placed onto this
2615 worklist, which, after performing dead code elimination, is walked
2616 to see which expressions need to be put into GC'able memory */
2617 static VEC(gimple, heap) *need_creation;
2618
2619 /* The actual worker for create_component_ref_by_pieces. */
2620
2621 static tree
2622 create_component_ref_by_pieces_1 (basic_block block, vn_reference_t ref,
2623 unsigned int *operand, gimple_seq *stmts,
2624 gimple domstmt)
2625 {
2626 vn_reference_op_t currop = VEC_index (vn_reference_op_s, ref->operands,
2627 *operand);
2628 tree genop;
2629 ++*operand;
2630 switch (currop->opcode)
2631 {
2632 case CALL_EXPR:
2633 {
2634 tree folded, sc = currop->op1;
2635 unsigned int nargs = 0;
2636 tree *args = XNEWVEC (tree, VEC_length (vn_reference_op_s,
2637 ref->operands) - 1);
2638 while (*operand < VEC_length (vn_reference_op_s, ref->operands))
2639 {
2640 args[nargs] = create_component_ref_by_pieces_1 (block, ref,
2641 operand, stmts,
2642 domstmt);
2643 nargs++;
2644 }
2645 folded = build_call_array (currop->type,
2646 TREE_CODE (currop->op0) == FUNCTION_DECL
2647 ? build_fold_addr_expr (currop->op0)
2648 : currop->op0,
2649 nargs, args);
2650 free (args);
2651 if (sc)
2652 {
2653 pre_expr scexpr = get_or_alloc_expr_for (sc);
2654 sc = find_or_generate_expression (block, scexpr, stmts, domstmt);
2655 if (!sc)
2656 return NULL_TREE;
2657 CALL_EXPR_STATIC_CHAIN (folded) = sc;
2658 }
2659 return folded;
2660 }
2661 break;
2662 case TARGET_MEM_REF:
2663 {
2664 vn_reference_op_t nextop = VEC_index (vn_reference_op_s, ref->operands,
2665 *operand);
2666 pre_expr op0expr;
2667 tree genop0 = NULL_TREE;
2668 tree baseop = create_component_ref_by_pieces_1 (block, ref, operand,
2669 stmts, domstmt);
2670 if (!baseop)
2671 return NULL_TREE;
2672 if (currop->op0)
2673 {
2674 op0expr = get_or_alloc_expr_for (currop->op0);
2675 genop0 = find_or_generate_expression (block, op0expr,
2676 stmts, domstmt);
2677 if (!genop0)
2678 return NULL_TREE;
2679 }
2680 if (DECL_P (baseop))
2681 return build6 (TARGET_MEM_REF, currop->type,
2682 baseop, NULL_TREE,
2683 genop0, currop->op1, currop->op2,
2684 unshare_expr (nextop->op1));
2685 else
2686 return build6 (TARGET_MEM_REF, currop->type,
2687 NULL_TREE, baseop,
2688 genop0, currop->op1, currop->op2,
2689 unshare_expr (nextop->op1));
2690 }
2691 break;
2692 case ADDR_EXPR:
2693 if (currop->op0)
2694 {
2695 gcc_assert (is_gimple_min_invariant (currop->op0));
2696 return currop->op0;
2697 }
2698 /* Fallthrough. */
2699 case REALPART_EXPR:
2700 case IMAGPART_EXPR:
2701 case VIEW_CONVERT_EXPR:
2702 {
2703 tree folded;
2704 tree genop0 = create_component_ref_by_pieces_1 (block, ref,
2705 operand,
2706 stmts, domstmt);
2707 if (!genop0)
2708 return NULL_TREE;
2709 folded = fold_build1 (currop->opcode, currop->type,
2710 genop0);
2711 return folded;
2712 }
2713 break;
2714 case ALIGN_INDIRECT_REF:
2715 case MISALIGNED_INDIRECT_REF:
2716 case INDIRECT_REF:
2717 {
2718 tree folded;
2719 tree genop1 = create_component_ref_by_pieces_1 (block, ref,
2720 operand,
2721 stmts, domstmt);
2722 if (!genop1)
2723 return NULL_TREE;
2724 genop1 = fold_convert (build_pointer_type (currop->type),
2725 genop1);
2726
2727 if (currop->opcode == MISALIGNED_INDIRECT_REF)
2728 folded = fold_build2 (currop->opcode, currop->type,
2729 genop1, currop->op1);
2730 else
2731 folded = fold_build1 (currop->opcode, currop->type,
2732 genop1);
2733 return folded;
2734 }
2735 break;
2736 case BIT_FIELD_REF:
2737 {
2738 tree folded;
2739 tree genop0 = create_component_ref_by_pieces_1 (block, ref, operand,
2740 stmts, domstmt);
2741 pre_expr op1expr = get_or_alloc_expr_for (currop->op0);
2742 pre_expr op2expr = get_or_alloc_expr_for (currop->op1);
2743 tree genop1;
2744 tree genop2;
2745
2746 if (!genop0)
2747 return NULL_TREE;
2748 genop1 = find_or_generate_expression (block, op1expr, stmts, domstmt);
2749 if (!genop1)
2750 return NULL_TREE;
2751 genop2 = find_or_generate_expression (block, op2expr, stmts, domstmt);
2752 if (!genop2)
2753 return NULL_TREE;
2754 folded = fold_build3 (BIT_FIELD_REF, currop->type, genop0, genop1,
2755 genop2);
2756 return folded;
2757 }
2758
2759 /* For array ref vn_reference_op's, operand 1 of the array ref
2760 is op0 of the reference op and operand 3 of the array ref is
2761 op1. */
2762 case ARRAY_RANGE_REF:
2763 case ARRAY_REF:
2764 {
2765 tree genop0;
2766 tree genop1 = currop->op0;
2767 pre_expr op1expr;
2768 tree genop2 = currop->op1;
2769 pre_expr op2expr;
2770 tree genop3 = currop->op2;
2771 pre_expr op3expr;
2772 genop0 = create_component_ref_by_pieces_1 (block, ref, operand,
2773 stmts, domstmt);
2774 if (!genop0)
2775 return NULL_TREE;
2776 op1expr = get_or_alloc_expr_for (genop1);
2777 genop1 = find_or_generate_expression (block, op1expr, stmts, domstmt);
2778 if (!genop1)
2779 return NULL_TREE;
2780 if (genop2)
2781 {
2782 op2expr = get_or_alloc_expr_for (genop2);
2783 genop2 = find_or_generate_expression (block, op2expr, stmts,
2784 domstmt);
2785 if (!genop2)
2786 return NULL_TREE;
2787 }
2788 if (genop3)
2789 {
2790 tree elmt_type = TREE_TYPE (TREE_TYPE (genop0));
2791 genop3 = size_binop (EXACT_DIV_EXPR, genop3,
2792 size_int (TYPE_ALIGN_UNIT (elmt_type)));
2793 op3expr = get_or_alloc_expr_for (genop3);
2794 genop3 = find_or_generate_expression (block, op3expr, stmts,
2795 domstmt);
2796 if (!genop3)
2797 return NULL_TREE;
2798 }
2799 return build4 (currop->opcode, currop->type, genop0, genop1,
2800 genop2, genop3);
2801 }
2802 case COMPONENT_REF:
2803 {
2804 tree op0;
2805 tree op1;
2806 tree genop2 = currop->op1;
2807 pre_expr op2expr;
2808 op0 = create_component_ref_by_pieces_1 (block, ref, operand,
2809 stmts, domstmt);
2810 if (!op0)
2811 return NULL_TREE;
2812 /* op1 should be a FIELD_DECL, which are represented by
2813 themselves. */
2814 op1 = currop->op0;
2815 if (genop2)
2816 {
2817 op2expr = get_or_alloc_expr_for (genop2);
2818 genop2 = find_or_generate_expression (block, op2expr, stmts,
2819 domstmt);
2820 if (!genop2)
2821 return NULL_TREE;
2822 }
2823
2824 return fold_build3 (COMPONENT_REF, TREE_TYPE (op1), op0, op1,
2825 genop2);
2826 }
2827 break;
2828 case SSA_NAME:
2829 {
2830 pre_expr op0expr = get_or_alloc_expr_for (currop->op0);
2831 genop = find_or_generate_expression (block, op0expr, stmts, domstmt);
2832 return genop;
2833 }
2834 case STRING_CST:
2835 case INTEGER_CST:
2836 case COMPLEX_CST:
2837 case VECTOR_CST:
2838 case REAL_CST:
2839 case CONSTRUCTOR:
2840 case VAR_DECL:
2841 case PARM_DECL:
2842 case CONST_DECL:
2843 case RESULT_DECL:
2844 case FUNCTION_DECL:
2845 return currop->op0;
2846
2847 default:
2848 gcc_unreachable ();
2849 }
2850 }
2851
2852 /* For COMPONENT_REF's and ARRAY_REF's, we can't have any intermediates for the
2853 COMPONENT_REF or INDIRECT_REF or ARRAY_REF portion, because we'd end up with
2854 trying to rename aggregates into ssa form directly, which is a no no.
2855
2856 Thus, this routine doesn't create temporaries, it just builds a
2857 single access expression for the array, calling
2858 find_or_generate_expression to build the innermost pieces.
2859
2860 This function is a subroutine of create_expression_by_pieces, and
2861 should not be called on it's own unless you really know what you
2862 are doing. */
2863
2864 static tree
2865 create_component_ref_by_pieces (basic_block block, vn_reference_t ref,
2866 gimple_seq *stmts, gimple domstmt)
2867 {
2868 unsigned int op = 0;
2869 return create_component_ref_by_pieces_1 (block, ref, &op, stmts, domstmt);
2870 }
2871
2872 /* Find a leader for an expression, or generate one using
2873 create_expression_by_pieces if it's ANTIC but
2874 complex.
2875 BLOCK is the basic_block we are looking for leaders in.
2876 EXPR is the expression to find a leader or generate for.
2877 STMTS is the statement list to put the inserted expressions on.
2878 Returns the SSA_NAME of the LHS of the generated expression or the
2879 leader.
2880 DOMSTMT if non-NULL is a statement that should be dominated by
2881 all uses in the generated expression. If DOMSTMT is non-NULL this
2882 routine can fail and return NULL_TREE. Otherwise it will assert
2883 on failure. */
2884
2885 static tree
2886 find_or_generate_expression (basic_block block, pre_expr expr,
2887 gimple_seq *stmts, gimple domstmt)
2888 {
2889 pre_expr leader = bitmap_find_leader (AVAIL_OUT (block),
2890 get_expr_value_id (expr), domstmt);
2891 tree genop = NULL;
2892 if (leader)
2893 {
2894 if (leader->kind == NAME)
2895 genop = PRE_EXPR_NAME (leader);
2896 else if (leader->kind == CONSTANT)
2897 genop = PRE_EXPR_CONSTANT (leader);
2898 }
2899
2900 /* If it's still NULL, it must be a complex expression, so generate
2901 it recursively. Not so for FRE though. */
2902 if (genop == NULL
2903 && !in_fre)
2904 {
2905 bitmap_set_t exprset;
2906 unsigned int lookfor = get_expr_value_id (expr);
2907 bool handled = false;
2908 bitmap_iterator bi;
2909 unsigned int i;
2910
2911 exprset = VEC_index (bitmap_set_t, value_expressions, lookfor);
2912 FOR_EACH_EXPR_ID_IN_SET (exprset, i, bi)
2913 {
2914 pre_expr temp = expression_for_id (i);
2915 if (temp->kind != NAME)
2916 {
2917 handled = true;
2918 genop = create_expression_by_pieces (block, temp, stmts,
2919 domstmt,
2920 get_expr_type (expr));
2921 break;
2922 }
2923 }
2924 if (!handled && domstmt)
2925 return NULL_TREE;
2926
2927 gcc_assert (handled);
2928 }
2929 return genop;
2930 }
2931
2932 #define NECESSARY GF_PLF_1
2933
2934 /* Create an expression in pieces, so that we can handle very complex
2935 expressions that may be ANTIC, but not necessary GIMPLE.
2936 BLOCK is the basic block the expression will be inserted into,
2937 EXPR is the expression to insert (in value form)
2938 STMTS is a statement list to append the necessary insertions into.
2939
2940 This function will die if we hit some value that shouldn't be
2941 ANTIC but is (IE there is no leader for it, or its components).
2942 This function may also generate expressions that are themselves
2943 partially or fully redundant. Those that are will be either made
2944 fully redundant during the next iteration of insert (for partially
2945 redundant ones), or eliminated by eliminate (for fully redundant
2946 ones).
2947
2948 If DOMSTMT is non-NULL then we make sure that all uses in the
2949 expressions dominate that statement. In this case the function
2950 can return NULL_TREE to signal failure. */
2951
2952 static tree
2953 create_expression_by_pieces (basic_block block, pre_expr expr,
2954 gimple_seq *stmts, gimple domstmt, tree type)
2955 {
2956 tree temp, name;
2957 tree folded;
2958 gimple_seq forced_stmts = NULL;
2959 unsigned int value_id;
2960 gimple_stmt_iterator gsi;
2961 tree exprtype = type ? type : get_expr_type (expr);
2962 pre_expr nameexpr;
2963 gimple newstmt;
2964
2965 switch (expr->kind)
2966 {
2967 /* We may hit the NAME/CONSTANT case if we have to convert types
2968 that value numbering saw through. */
2969 case NAME:
2970 folded = PRE_EXPR_NAME (expr);
2971 break;
2972 case CONSTANT:
2973 folded = PRE_EXPR_CONSTANT (expr);
2974 break;
2975 case REFERENCE:
2976 {
2977 vn_reference_t ref = PRE_EXPR_REFERENCE (expr);
2978 folded = create_component_ref_by_pieces (block, ref, stmts, domstmt);
2979 }
2980 break;
2981 case NARY:
2982 {
2983 vn_nary_op_t nary = PRE_EXPR_NARY (expr);
2984 switch (nary->length)
2985 {
2986 case 2:
2987 {
2988 pre_expr op1 = get_or_alloc_expr_for (nary->op[0]);
2989 pre_expr op2 = get_or_alloc_expr_for (nary->op[1]);
2990 tree genop1 = find_or_generate_expression (block, op1,
2991 stmts, domstmt);
2992 tree genop2 = find_or_generate_expression (block, op2,
2993 stmts, domstmt);
2994 if (!genop1 || !genop2)
2995 return NULL_TREE;
2996 /* Ensure op2 is a sizetype for POINTER_PLUS_EXPR. It
2997 may be a constant with the wrong type. */
2998 if (nary->opcode == POINTER_PLUS_EXPR)
2999 {
3000 genop1 = fold_convert (nary->type, genop1);
3001 genop2 = fold_convert (sizetype, genop2);
3002 }
3003 else
3004 {
3005 genop1 = fold_convert (TREE_TYPE (nary->op[0]), genop1);
3006 genop2 = fold_convert (TREE_TYPE (nary->op[1]), genop2);
3007 }
3008
3009 folded = fold_build2 (nary->opcode, nary->type,
3010 genop1, genop2);
3011 }
3012 break;
3013 case 1:
3014 {
3015 pre_expr op1 = get_or_alloc_expr_for (nary->op[0]);
3016 tree genop1 = find_or_generate_expression (block, op1,
3017 stmts, domstmt);
3018 if (!genop1)
3019 return NULL_TREE;
3020 genop1 = fold_convert (TREE_TYPE (nary->op[0]), genop1);
3021
3022 folded = fold_build1 (nary->opcode, nary->type,
3023 genop1);
3024 }
3025 break;
3026 default:
3027 return NULL_TREE;
3028 }
3029 }
3030 break;
3031 default:
3032 return NULL_TREE;
3033 }
3034
3035 if (!useless_type_conversion_p (exprtype, TREE_TYPE (folded)))
3036 folded = fold_convert (exprtype, folded);
3037
3038 /* Force the generated expression to be a sequence of GIMPLE
3039 statements.
3040 We have to call unshare_expr because force_gimple_operand may
3041 modify the tree we pass to it. */
3042 folded = force_gimple_operand (unshare_expr (folded), &forced_stmts,
3043 false, NULL);
3044
3045 /* If we have any intermediate expressions to the value sets, add them
3046 to the value sets and chain them in the instruction stream. */
3047 if (forced_stmts)
3048 {
3049 gsi = gsi_start (forced_stmts);
3050 for (; !gsi_end_p (gsi); gsi_next (&gsi))
3051 {
3052 gimple stmt = gsi_stmt (gsi);
3053 tree forcedname = gimple_get_lhs (stmt);
3054 pre_expr nameexpr;
3055
3056 VEC_safe_push (gimple, heap, inserted_exprs, stmt);
3057 if (TREE_CODE (forcedname) == SSA_NAME)
3058 {
3059 VN_INFO_GET (forcedname)->valnum = forcedname;
3060 VN_INFO (forcedname)->value_id = get_next_value_id ();
3061 nameexpr = get_or_alloc_expr_for_name (forcedname);
3062 add_to_value (VN_INFO (forcedname)->value_id, nameexpr);
3063 if (!in_fre)
3064 bitmap_value_replace_in_set (NEW_SETS (block), nameexpr);
3065 bitmap_value_replace_in_set (AVAIL_OUT (block), nameexpr);
3066 }
3067 mark_symbols_for_renaming (stmt);
3068 }
3069 gimple_seq_add_seq (stmts, forced_stmts);
3070 }
3071
3072 /* Build and insert the assignment of the end result to the temporary
3073 that we will return. */
3074 if (!pretemp || exprtype != TREE_TYPE (pretemp))
3075 {
3076 pretemp = create_tmp_var (exprtype, "pretmp");
3077 get_var_ann (pretemp);
3078 }
3079
3080 temp = pretemp;
3081 add_referenced_var (temp);
3082
3083 if (TREE_CODE (exprtype) == COMPLEX_TYPE
3084 || TREE_CODE (exprtype) == VECTOR_TYPE)
3085 DECL_GIMPLE_REG_P (temp) = 1;
3086
3087 newstmt = gimple_build_assign (temp, folded);
3088 name = make_ssa_name (temp, newstmt);
3089 gimple_assign_set_lhs (newstmt, name);
3090 gimple_set_plf (newstmt, NECESSARY, false);
3091
3092 gimple_seq_add_stmt (stmts, newstmt);
3093 VEC_safe_push (gimple, heap, inserted_exprs, newstmt);
3094
3095 /* All the symbols in NEWEXPR should be put into SSA form. */
3096 mark_symbols_for_renaming (newstmt);
3097
3098 /* Add a value number to the temporary.
3099 The value may already exist in either NEW_SETS, or AVAIL_OUT, because
3100 we are creating the expression by pieces, and this particular piece of
3101 the expression may have been represented. There is no harm in replacing
3102 here. */
3103 VN_INFO_GET (name)->valnum = name;
3104 value_id = get_expr_value_id (expr);
3105 VN_INFO (name)->value_id = value_id;
3106 nameexpr = get_or_alloc_expr_for_name (name);
3107 add_to_value (value_id, nameexpr);
3108 if (!in_fre)
3109 bitmap_value_replace_in_set (NEW_SETS (block), nameexpr);
3110 bitmap_value_replace_in_set (AVAIL_OUT (block), nameexpr);
3111
3112 pre_stats.insertions++;
3113 if (dump_file && (dump_flags & TDF_DETAILS))
3114 {
3115 fprintf (dump_file, "Inserted ");
3116 print_gimple_stmt (dump_file, newstmt, 0, 0);
3117 fprintf (dump_file, " in predecessor %d\n", block->index);
3118 }
3119
3120 return name;
3121 }
3122
3123
3124 /* Returns true if we want to inhibit the insertions of PHI nodes
3125 for the given EXPR for basic block BB (a member of a loop).
3126 We want to do this, when we fear that the induction variable we
3127 create might inhibit vectorization. */
3128
3129 static bool
3130 inhibit_phi_insertion (basic_block bb, pre_expr expr)
3131 {
3132 vn_reference_t vr = PRE_EXPR_REFERENCE (expr);
3133 VEC (vn_reference_op_s, heap) *ops = vr->operands;
3134 vn_reference_op_t op;
3135 unsigned i;
3136
3137 /* If we aren't going to vectorize we don't inhibit anything. */
3138 if (!flag_tree_vectorize)
3139 return false;
3140
3141 /* Otherwise we inhibit the insertion when the address of the
3142 memory reference is a simple induction variable. In other
3143 cases the vectorizer won't do anything anyway (either it's
3144 loop invariant or a complicated expression). */
3145 for (i = 0; VEC_iterate (vn_reference_op_s, ops, i, op); ++i)
3146 {
3147 switch (op->opcode)
3148 {
3149 case ARRAY_REF:
3150 case ARRAY_RANGE_REF:
3151 if (TREE_CODE (op->op0) != SSA_NAME)
3152 break;
3153 /* Fallthru. */
3154 case SSA_NAME:
3155 {
3156 basic_block defbb = gimple_bb (SSA_NAME_DEF_STMT (op->op0));
3157 affine_iv iv;
3158 /* Default defs are loop invariant. */
3159 if (!defbb)
3160 break;
3161 /* Defined outside this loop, also loop invariant. */
3162 if (!flow_bb_inside_loop_p (bb->loop_father, defbb))
3163 break;
3164 /* If it's a simple induction variable inhibit insertion,
3165 the vectorizer might be interested in this one. */
3166 if (simple_iv (bb->loop_father, bb->loop_father,
3167 op->op0, &iv, true))
3168 return true;
3169 /* No simple IV, vectorizer can't do anything, hence no
3170 reason to inhibit the transformation for this operand. */
3171 break;
3172 }
3173 default:
3174 break;
3175 }
3176 }
3177 return false;
3178 }
3179
3180 /* Insert the to-be-made-available values of expression EXPRNUM for each
3181 predecessor, stored in AVAIL, into the predecessors of BLOCK, and
3182 merge the result with a phi node, given the same value number as
3183 NODE. Return true if we have inserted new stuff. */
3184
3185 static bool
3186 insert_into_preds_of_block (basic_block block, unsigned int exprnum,
3187 pre_expr *avail)
3188 {
3189 pre_expr expr = expression_for_id (exprnum);
3190 pre_expr newphi;
3191 unsigned int val = get_expr_value_id (expr);
3192 edge pred;
3193 bool insertions = false;
3194 bool nophi = false;
3195 basic_block bprime;
3196 pre_expr eprime;
3197 edge_iterator ei;
3198 tree type = get_expr_type (expr);
3199 tree temp;
3200 gimple phi;
3201
3202 if (dump_file && (dump_flags & TDF_DETAILS))
3203 {
3204 fprintf (dump_file, "Found partial redundancy for expression ");
3205 print_pre_expr (dump_file, expr);
3206 fprintf (dump_file, " (%04d)\n", val);
3207 }
3208
3209 /* Make sure we aren't creating an induction variable. */
3210 if (block->loop_depth > 0 && EDGE_COUNT (block->preds) == 2)
3211 {
3212 bool firstinsideloop = false;
3213 bool secondinsideloop = false;
3214 firstinsideloop = flow_bb_inside_loop_p (block->loop_father,
3215 EDGE_PRED (block, 0)->src);
3216 secondinsideloop = flow_bb_inside_loop_p (block->loop_father,
3217 EDGE_PRED (block, 1)->src);
3218 /* Induction variables only have one edge inside the loop. */
3219 if ((firstinsideloop ^ secondinsideloop)
3220 && (expr->kind != REFERENCE
3221 || inhibit_phi_insertion (block, expr)))
3222 {
3223 if (dump_file && (dump_flags & TDF_DETAILS))
3224 fprintf (dump_file, "Skipping insertion of phi for partial redundancy: Looks like an induction variable\n");
3225 nophi = true;
3226 }
3227 }
3228
3229 /* Make the necessary insertions. */
3230 FOR_EACH_EDGE (pred, ei, block->preds)
3231 {
3232 gimple_seq stmts = NULL;
3233 tree builtexpr;
3234 bprime = pred->src;
3235 eprime = avail[bprime->index];
3236
3237 if (eprime->kind != NAME && eprime->kind != CONSTANT)
3238 {
3239 builtexpr = create_expression_by_pieces (bprime,
3240 eprime,
3241 &stmts, NULL,
3242 type);
3243 gcc_assert (!(pred->flags & EDGE_ABNORMAL));
3244 gsi_insert_seq_on_edge (pred, stmts);
3245 avail[bprime->index] = get_or_alloc_expr_for_name (builtexpr);
3246 insertions = true;
3247 }
3248 else if (eprime->kind == CONSTANT)
3249 {
3250 /* Constants may not have the right type, fold_convert
3251 should give us back a constant with the right type.
3252 */
3253 tree constant = PRE_EXPR_CONSTANT (eprime);
3254 if (!useless_type_conversion_p (type, TREE_TYPE (constant)))
3255 {
3256 tree builtexpr = fold_convert (type, constant);
3257 if (!is_gimple_min_invariant (builtexpr))
3258 {
3259 tree forcedexpr = force_gimple_operand (builtexpr,
3260 &stmts, true,
3261 NULL);
3262 if (!is_gimple_min_invariant (forcedexpr))
3263 {
3264 if (forcedexpr != builtexpr)
3265 {
3266 VN_INFO_GET (forcedexpr)->valnum = PRE_EXPR_CONSTANT (eprime);
3267 VN_INFO (forcedexpr)->value_id = get_expr_value_id (eprime);
3268 }
3269 if (stmts)
3270 {
3271 gimple_stmt_iterator gsi;
3272 gsi = gsi_start (stmts);
3273 for (; !gsi_end_p (gsi); gsi_next (&gsi))
3274 {
3275 gimple stmt = gsi_stmt (gsi);
3276 VEC_safe_push (gimple, heap, inserted_exprs, stmt);
3277 gimple_set_plf (stmt, NECESSARY, false);
3278 }
3279 gsi_insert_seq_on_edge (pred, stmts);
3280 }
3281 avail[bprime->index] = get_or_alloc_expr_for_name (forcedexpr);
3282 }
3283 }
3284 }
3285 }
3286 else if (eprime->kind == NAME)
3287 {
3288 /* We may have to do a conversion because our value
3289 numbering can look through types in certain cases, but
3290 our IL requires all operands of a phi node have the same
3291 type. */
3292 tree name = PRE_EXPR_NAME (eprime);
3293 if (!useless_type_conversion_p (type, TREE_TYPE (name)))
3294 {
3295 tree builtexpr;
3296 tree forcedexpr;
3297 builtexpr = fold_convert (type, name);
3298 forcedexpr = force_gimple_operand (builtexpr,
3299 &stmts, true,
3300 NULL);
3301
3302 if (forcedexpr != name)
3303 {
3304 VN_INFO_GET (forcedexpr)->valnum = VN_INFO (name)->valnum;
3305 VN_INFO (forcedexpr)->value_id = VN_INFO (name)->value_id;
3306 }
3307
3308 if (stmts)
3309 {
3310 gimple_stmt_iterator gsi;
3311 gsi = gsi_start (stmts);
3312 for (; !gsi_end_p (gsi); gsi_next (&gsi))
3313 {
3314 gimple stmt = gsi_stmt (gsi);
3315 VEC_safe_push (gimple, heap, inserted_exprs, stmt);
3316 gimple_set_plf (stmt, NECESSARY, false);
3317 }
3318 gsi_insert_seq_on_edge (pred, stmts);
3319 }
3320 avail[bprime->index] = get_or_alloc_expr_for_name (forcedexpr);
3321 }
3322 }
3323 }
3324 /* If we didn't want a phi node, and we made insertions, we still have
3325 inserted new stuff, and thus return true. If we didn't want a phi node,
3326 and didn't make insertions, we haven't added anything new, so return
3327 false. */
3328 if (nophi && insertions)
3329 return true;
3330 else if (nophi && !insertions)
3331 return false;
3332
3333 /* Now build a phi for the new variable. */
3334 if (!prephitemp || TREE_TYPE (prephitemp) != type)
3335 {
3336 prephitemp = create_tmp_var (type, "prephitmp");
3337 get_var_ann (prephitemp);
3338 }
3339
3340 temp = prephitemp;
3341 add_referenced_var (temp);
3342
3343 if (TREE_CODE (type) == COMPLEX_TYPE
3344 || TREE_CODE (type) == VECTOR_TYPE)
3345 DECL_GIMPLE_REG_P (temp) = 1;
3346 phi = create_phi_node (temp, block);
3347
3348 gimple_set_plf (phi, NECESSARY, false);
3349 VN_INFO_GET (gimple_phi_result (phi))->valnum = gimple_phi_result (phi);
3350 VN_INFO (gimple_phi_result (phi))->value_id = val;
3351 VEC_safe_push (gimple, heap, inserted_exprs, phi);
3352 bitmap_set_bit (inserted_phi_names,
3353 SSA_NAME_VERSION (gimple_phi_result (phi)));
3354 FOR_EACH_EDGE (pred, ei, block->preds)
3355 {
3356 pre_expr ae = avail[pred->src->index];
3357 gcc_assert (get_expr_type (ae) == type
3358 || useless_type_conversion_p (type, get_expr_type (ae)));
3359 if (ae->kind == CONSTANT)
3360 add_phi_arg (phi, PRE_EXPR_CONSTANT (ae), pred, UNKNOWN_LOCATION);
3361 else
3362 add_phi_arg (phi, PRE_EXPR_NAME (avail[pred->src->index]), pred,
3363 UNKNOWN_LOCATION);
3364 }
3365
3366 newphi = get_or_alloc_expr_for_name (gimple_phi_result (phi));
3367 add_to_value (val, newphi);
3368
3369 /* The value should *not* exist in PHI_GEN, or else we wouldn't be doing
3370 this insertion, since we test for the existence of this value in PHI_GEN
3371 before proceeding with the partial redundancy checks in insert_aux.
3372
3373 The value may exist in AVAIL_OUT, in particular, it could be represented
3374 by the expression we are trying to eliminate, in which case we want the
3375 replacement to occur. If it's not existing in AVAIL_OUT, we want it
3376 inserted there.
3377
3378 Similarly, to the PHI_GEN case, the value should not exist in NEW_SETS of
3379 this block, because if it did, it would have existed in our dominator's
3380 AVAIL_OUT, and would have been skipped due to the full redundancy check.
3381 */
3382
3383 bitmap_insert_into_set (PHI_GEN (block), newphi);
3384 bitmap_value_replace_in_set (AVAIL_OUT (block),
3385 newphi);
3386 bitmap_insert_into_set (NEW_SETS (block),
3387 newphi);
3388
3389 if (dump_file && (dump_flags & TDF_DETAILS))
3390 {
3391 fprintf (dump_file, "Created phi ");
3392 print_gimple_stmt (dump_file, phi, 0, 0);
3393 fprintf (dump_file, " in block %d\n", block->index);
3394 }
3395 pre_stats.phis++;
3396 return true;
3397 }
3398
3399
3400
3401 /* Perform insertion of partially redundant values.
3402 For BLOCK, do the following:
3403 1. Propagate the NEW_SETS of the dominator into the current block.
3404 If the block has multiple predecessors,
3405 2a. Iterate over the ANTIC expressions for the block to see if
3406 any of them are partially redundant.
3407 2b. If so, insert them into the necessary predecessors to make
3408 the expression fully redundant.
3409 2c. Insert a new PHI merging the values of the predecessors.
3410 2d. Insert the new PHI, and the new expressions, into the
3411 NEW_SETS set.
3412 3. Recursively call ourselves on the dominator children of BLOCK.
3413
3414 Steps 1, 2a, and 3 are done by insert_aux. 2b, 2c and 2d are done by
3415 do_regular_insertion and do_partial_insertion.
3416
3417 */
3418
3419 static bool
3420 do_regular_insertion (basic_block block, basic_block dom)
3421 {
3422 bool new_stuff = false;
3423 VEC (pre_expr, heap) *exprs = sorted_array_from_bitmap_set (ANTIC_IN (block));
3424 pre_expr expr;
3425 int i;
3426
3427 for (i = 0; VEC_iterate (pre_expr, exprs, i, expr); i++)
3428 {
3429 if (expr->kind != NAME)
3430 {
3431 pre_expr *avail;
3432 unsigned int val;
3433 bool by_some = false;
3434 bool cant_insert = false;
3435 bool all_same = true;
3436 pre_expr first_s = NULL;
3437 edge pred;
3438 basic_block bprime;
3439 pre_expr eprime = NULL;
3440 edge_iterator ei;
3441 pre_expr edoubleprime = NULL;
3442 bool do_insertion = false;
3443
3444 val = get_expr_value_id (expr);
3445 if (bitmap_set_contains_value (PHI_GEN (block), val))
3446 continue;
3447 if (bitmap_set_contains_value (AVAIL_OUT (dom), val))
3448 {
3449 if (dump_file && (dump_flags & TDF_DETAILS))
3450 fprintf (dump_file, "Found fully redundant value\n");
3451 continue;
3452 }
3453
3454 avail = XCNEWVEC (pre_expr, last_basic_block);
3455 FOR_EACH_EDGE (pred, ei, block->preds)
3456 {
3457 unsigned int vprime;
3458
3459 /* We should never run insertion for the exit block
3460 and so not come across fake pred edges. */
3461 gcc_assert (!(pred->flags & EDGE_FAKE));
3462 bprime = pred->src;
3463 eprime = phi_translate (expr, ANTIC_IN (block), NULL,
3464 bprime, block);
3465
3466 /* eprime will generally only be NULL if the
3467 value of the expression, translated
3468 through the PHI for this predecessor, is
3469 undefined. If that is the case, we can't
3470 make the expression fully redundant,
3471 because its value is undefined along a
3472 predecessor path. We can thus break out
3473 early because it doesn't matter what the
3474 rest of the results are. */
3475 if (eprime == NULL)
3476 {
3477 cant_insert = true;
3478 break;
3479 }
3480
3481 eprime = fully_constant_expression (eprime);
3482 vprime = get_expr_value_id (eprime);
3483 edoubleprime = bitmap_find_leader (AVAIL_OUT (bprime),
3484 vprime, NULL);
3485 if (edoubleprime == NULL)
3486 {
3487 avail[bprime->index] = eprime;
3488 all_same = false;
3489 }
3490 else
3491 {
3492 avail[bprime->index] = edoubleprime;
3493 by_some = true;
3494 /* We want to perform insertions to remove a redundancy on
3495 a path in the CFG we want to optimize for speed. */
3496 if (optimize_edge_for_speed_p (pred))
3497 do_insertion = true;
3498 if (first_s == NULL)
3499 first_s = edoubleprime;
3500 else if (!pre_expr_eq (first_s, edoubleprime))
3501 all_same = false;
3502 }
3503 }
3504 /* If we can insert it, it's not the same value
3505 already existing along every predecessor, and
3506 it's defined by some predecessor, it is
3507 partially redundant. */
3508 if (!cant_insert && !all_same && by_some && do_insertion
3509 && dbg_cnt (treepre_insert))
3510 {
3511 if (insert_into_preds_of_block (block, get_expression_id (expr),
3512 avail))
3513 new_stuff = true;
3514 }
3515 /* If all edges produce the same value and that value is
3516 an invariant, then the PHI has the same value on all
3517 edges. Note this. */
3518 else if (!cant_insert && all_same && eprime
3519 && (edoubleprime->kind == CONSTANT
3520 || edoubleprime->kind == NAME)
3521 && !value_id_constant_p (val))
3522 {
3523 unsigned int j;
3524 bitmap_iterator bi;
3525 bitmap_set_t exprset = VEC_index (bitmap_set_t,
3526 value_expressions, val);
3527
3528 unsigned int new_val = get_expr_value_id (edoubleprime);
3529 FOR_EACH_EXPR_ID_IN_SET (exprset, j, bi)
3530 {
3531 pre_expr expr = expression_for_id (j);
3532
3533 if (expr->kind == NAME)
3534 {
3535 vn_ssa_aux_t info = VN_INFO (PRE_EXPR_NAME (expr));
3536 /* Just reset the value id and valnum so it is
3537 the same as the constant we have discovered. */
3538 if (edoubleprime->kind == CONSTANT)
3539 {
3540 info->valnum = PRE_EXPR_CONSTANT (edoubleprime);
3541 pre_stats.constified++;
3542 }
3543 else
3544 info->valnum = VN_INFO (PRE_EXPR_NAME (edoubleprime))->valnum;
3545 info->value_id = new_val;
3546 }
3547 }
3548 }
3549 free (avail);
3550 }
3551 }
3552
3553 VEC_free (pre_expr, heap, exprs);
3554 return new_stuff;
3555 }
3556
3557
3558 /* Perform insertion for partially anticipatable expressions. There
3559 is only one case we will perform insertion for these. This case is
3560 if the expression is partially anticipatable, and fully available.
3561 In this case, we know that putting it earlier will enable us to
3562 remove the later computation. */
3563
3564
3565 static bool
3566 do_partial_partial_insertion (basic_block block, basic_block dom)
3567 {
3568 bool new_stuff = false;
3569 VEC (pre_expr, heap) *exprs = sorted_array_from_bitmap_set (PA_IN (block));
3570 pre_expr expr;
3571 int i;
3572
3573 for (i = 0; VEC_iterate (pre_expr, exprs, i, expr); i++)
3574 {
3575 if (expr->kind != NAME)
3576 {
3577 pre_expr *avail;
3578 unsigned int val;
3579 bool by_all = true;
3580 bool cant_insert = false;
3581 edge pred;
3582 basic_block bprime;
3583 pre_expr eprime = NULL;
3584 edge_iterator ei;
3585
3586 val = get_expr_value_id (expr);
3587 if (bitmap_set_contains_value (PHI_GEN (block), val))
3588 continue;
3589 if (bitmap_set_contains_value (AVAIL_OUT (dom), val))
3590 continue;
3591
3592 avail = XCNEWVEC (pre_expr, last_basic_block);
3593 FOR_EACH_EDGE (pred, ei, block->preds)
3594 {
3595 unsigned int vprime;
3596 pre_expr edoubleprime;
3597
3598 /* We should never run insertion for the exit block
3599 and so not come across fake pred edges. */
3600 gcc_assert (!(pred->flags & EDGE_FAKE));
3601 bprime = pred->src;
3602 eprime = phi_translate (expr, ANTIC_IN (block),
3603 PA_IN (block),
3604 bprime, block);
3605
3606 /* eprime will generally only be NULL if the
3607 value of the expression, translated
3608 through the PHI for this predecessor, is
3609 undefined. If that is the case, we can't
3610 make the expression fully redundant,
3611 because its value is undefined along a
3612 predecessor path. We can thus break out
3613 early because it doesn't matter what the
3614 rest of the results are. */
3615 if (eprime == NULL)
3616 {
3617 cant_insert = true;
3618 break;
3619 }
3620
3621 eprime = fully_constant_expression (eprime);
3622 vprime = get_expr_value_id (eprime);
3623 edoubleprime = bitmap_find_leader (AVAIL_OUT (bprime),
3624 vprime, NULL);
3625 if (edoubleprime == NULL)
3626 {
3627 by_all = false;
3628 break;
3629 }
3630 else
3631 avail[bprime->index] = edoubleprime;
3632
3633 }
3634
3635 /* If we can insert it, it's not the same value
3636 already existing along every predecessor, and
3637 it's defined by some predecessor, it is
3638 partially redundant. */
3639 if (!cant_insert && by_all && dbg_cnt (treepre_insert))
3640 {
3641 pre_stats.pa_insert++;
3642 if (insert_into_preds_of_block (block, get_expression_id (expr),
3643 avail))
3644 new_stuff = true;
3645 }
3646 free (avail);
3647 }
3648 }
3649
3650 VEC_free (pre_expr, heap, exprs);
3651 return new_stuff;
3652 }
3653
3654 static bool
3655 insert_aux (basic_block block)
3656 {
3657 basic_block son;
3658 bool new_stuff = false;
3659
3660 if (block)
3661 {
3662 basic_block dom;
3663 dom = get_immediate_dominator (CDI_DOMINATORS, block);
3664 if (dom)
3665 {
3666 unsigned i;
3667 bitmap_iterator bi;
3668 bitmap_set_t newset = NEW_SETS (dom);
3669 if (newset)
3670 {
3671 /* Note that we need to value_replace both NEW_SETS, and
3672 AVAIL_OUT. For both the case of NEW_SETS, the value may be
3673 represented by some non-simple expression here that we want
3674 to replace it with. */
3675 FOR_EACH_EXPR_ID_IN_SET (newset, i, bi)
3676 {
3677 pre_expr expr = expression_for_id (i);
3678 bitmap_value_replace_in_set (NEW_SETS (block), expr);
3679 bitmap_value_replace_in_set (AVAIL_OUT (block), expr);
3680 }
3681 }
3682 if (!single_pred_p (block))
3683 {
3684 new_stuff |= do_regular_insertion (block, dom);
3685 if (do_partial_partial)
3686 new_stuff |= do_partial_partial_insertion (block, dom);
3687 }
3688 }
3689 }
3690 for (son = first_dom_son (CDI_DOMINATORS, block);
3691 son;
3692 son = next_dom_son (CDI_DOMINATORS, son))
3693 {
3694 new_stuff |= insert_aux (son);
3695 }
3696
3697 return new_stuff;
3698 }
3699
3700 /* Perform insertion of partially redundant values. */
3701
3702 static void
3703 insert (void)
3704 {
3705 bool new_stuff = true;
3706 basic_block bb;
3707 int num_iterations = 0;
3708
3709 FOR_ALL_BB (bb)
3710 NEW_SETS (bb) = bitmap_set_new ();
3711
3712 while (new_stuff)
3713 {
3714 num_iterations++;
3715 new_stuff = insert_aux (ENTRY_BLOCK_PTR);
3716 }
3717 statistics_histogram_event (cfun, "insert iterations", num_iterations);
3718 }
3719
3720
3721 /* Add OP to EXP_GEN (block), and possibly to the maximal set. */
3722
3723 static void
3724 add_to_exp_gen (basic_block block, tree op)
3725 {
3726 if (!in_fre)
3727 {
3728 pre_expr result;
3729 if (TREE_CODE (op) == SSA_NAME && ssa_undefined_value_p (op))
3730 return;
3731 result = get_or_alloc_expr_for_name (op);
3732 bitmap_value_insert_into_set (EXP_GEN (block), result);
3733 }
3734 }
3735
3736 /* Create value ids for PHI in BLOCK. */
3737
3738 static void
3739 make_values_for_phi (gimple phi, basic_block block)
3740 {
3741 tree result = gimple_phi_result (phi);
3742
3743 /* We have no need for virtual phis, as they don't represent
3744 actual computations. */
3745 if (is_gimple_reg (result))
3746 {
3747 pre_expr e = get_or_alloc_expr_for_name (result);
3748 add_to_value (get_expr_value_id (e), e);
3749 bitmap_insert_into_set (PHI_GEN (block), e);
3750 bitmap_value_insert_into_set (AVAIL_OUT (block), e);
3751 if (!in_fre)
3752 {
3753 unsigned i;
3754 for (i = 0; i < gimple_phi_num_args (phi); ++i)
3755 {
3756 tree arg = gimple_phi_arg_def (phi, i);
3757 if (TREE_CODE (arg) == SSA_NAME)
3758 {
3759 e = get_or_alloc_expr_for_name (arg);
3760 add_to_value (get_expr_value_id (e), e);
3761 }
3762 }
3763 }
3764 }
3765 }
3766
3767 /* Compute the AVAIL set for all basic blocks.
3768
3769 This function performs value numbering of the statements in each basic
3770 block. The AVAIL sets are built from information we glean while doing
3771 this value numbering, since the AVAIL sets contain only one entry per
3772 value.
3773
3774 AVAIL_IN[BLOCK] = AVAIL_OUT[dom(BLOCK)].
3775 AVAIL_OUT[BLOCK] = AVAIL_IN[BLOCK] U PHI_GEN[BLOCK] U TMP_GEN[BLOCK]. */
3776
3777 static void
3778 compute_avail (void)
3779 {
3780
3781 basic_block block, son;
3782 basic_block *worklist;
3783 size_t sp = 0;
3784 unsigned i;
3785
3786 /* We pretend that default definitions are defined in the entry block.
3787 This includes function arguments and the static chain decl. */
3788 for (i = 1; i < num_ssa_names; ++i)
3789 {
3790 tree name = ssa_name (i);
3791 pre_expr e;
3792 if (!name
3793 || !SSA_NAME_IS_DEFAULT_DEF (name)
3794 || has_zero_uses (name)
3795 || !is_gimple_reg (name))
3796 continue;
3797
3798 e = get_or_alloc_expr_for_name (name);
3799 add_to_value (get_expr_value_id (e), e);
3800 if (!in_fre)
3801 bitmap_insert_into_set (TMP_GEN (ENTRY_BLOCK_PTR), e);
3802 bitmap_value_insert_into_set (AVAIL_OUT (ENTRY_BLOCK_PTR), e);
3803 }
3804
3805 /* Allocate the worklist. */
3806 worklist = XNEWVEC (basic_block, n_basic_blocks);
3807
3808 /* Seed the algorithm by putting the dominator children of the entry
3809 block on the worklist. */
3810 for (son = first_dom_son (CDI_DOMINATORS, ENTRY_BLOCK_PTR);
3811 son;
3812 son = next_dom_son (CDI_DOMINATORS, son))
3813 worklist[sp++] = son;
3814
3815 /* Loop until the worklist is empty. */
3816 while (sp)
3817 {
3818 gimple_stmt_iterator gsi;
3819 gimple stmt;
3820 basic_block dom;
3821 unsigned int stmt_uid = 1;
3822
3823 /* Pick a block from the worklist. */
3824 block = worklist[--sp];
3825
3826 /* Initially, the set of available values in BLOCK is that of
3827 its immediate dominator. */
3828 dom = get_immediate_dominator (CDI_DOMINATORS, block);
3829 if (dom)
3830 bitmap_set_copy (AVAIL_OUT (block), AVAIL_OUT (dom));
3831
3832 /* Generate values for PHI nodes. */
3833 for (gsi = gsi_start_phis (block); !gsi_end_p (gsi); gsi_next (&gsi))
3834 make_values_for_phi (gsi_stmt (gsi), block);
3835
3836 BB_MAY_NOTRETURN (block) = 0;
3837
3838 /* Now compute value numbers and populate value sets with all
3839 the expressions computed in BLOCK. */
3840 for (gsi = gsi_start_bb (block); !gsi_end_p (gsi); gsi_next (&gsi))
3841 {
3842 ssa_op_iter iter;
3843 tree op;
3844
3845 stmt = gsi_stmt (gsi);
3846 gimple_set_uid (stmt, stmt_uid++);
3847
3848 /* Cache whether the basic-block has any non-visible side-effect
3849 or control flow.
3850 If this isn't a call or it is the last stmt in the
3851 basic-block then the CFG represents things correctly. */
3852 if (is_gimple_call (stmt)
3853 && !stmt_ends_bb_p (stmt))
3854 {
3855 /* Non-looping const functions always return normally.
3856 Otherwise the call might not return or have side-effects
3857 that forbids hoisting possibly trapping expressions
3858 before it. */
3859 int flags = gimple_call_flags (stmt);
3860 if (!(flags & ECF_CONST)
3861 || (flags & ECF_LOOPING_CONST_OR_PURE))
3862 BB_MAY_NOTRETURN (block) = 1;
3863 }
3864
3865 FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_DEF)
3866 {
3867 pre_expr e = get_or_alloc_expr_for_name (op);
3868
3869 add_to_value (get_expr_value_id (e), e);
3870 if (!in_fre)
3871 bitmap_insert_into_set (TMP_GEN (block), e);
3872 bitmap_value_insert_into_set (AVAIL_OUT (block), e);
3873 }
3874
3875 if (gimple_has_volatile_ops (stmt)
3876 || stmt_could_throw_p (stmt))
3877 continue;
3878
3879 switch (gimple_code (stmt))
3880 {
3881 case GIMPLE_RETURN:
3882 FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_USE)
3883 add_to_exp_gen (block, op);
3884 continue;
3885
3886 case GIMPLE_CALL:
3887 {
3888 vn_reference_t ref;
3889 unsigned int i;
3890 vn_reference_op_t vro;
3891 pre_expr result = NULL;
3892 VEC(vn_reference_op_s, heap) *ops = NULL;
3893
3894 if (!can_value_number_call (stmt))
3895 continue;
3896
3897 copy_reference_ops_from_call (stmt, &ops);
3898 vn_reference_lookup_pieces (gimple_vuse (stmt), 0,
3899 gimple_expr_type (stmt),
3900 ops, &ref, false);
3901 VEC_free (vn_reference_op_s, heap, ops);
3902 if (!ref)
3903 continue;
3904
3905 for (i = 0; VEC_iterate (vn_reference_op_s,
3906 ref->operands, i,
3907 vro); i++)
3908 {
3909 if (vro->op0 && TREE_CODE (vro->op0) == SSA_NAME)
3910 add_to_exp_gen (block, vro->op0);
3911 if (vro->op1 && TREE_CODE (vro->op1) == SSA_NAME)
3912 add_to_exp_gen (block, vro->op1);
3913 if (vro->op2 && TREE_CODE (vro->op2) == SSA_NAME)
3914 add_to_exp_gen (block, vro->op2);
3915 }
3916 result = (pre_expr) pool_alloc (pre_expr_pool);
3917 result->kind = REFERENCE;
3918 result->id = 0;
3919 PRE_EXPR_REFERENCE (result) = ref;
3920
3921 get_or_alloc_expression_id (result);
3922 add_to_value (get_expr_value_id (result), result);
3923 if (!in_fre)
3924 bitmap_value_insert_into_set (EXP_GEN (block), result);
3925 continue;
3926 }
3927
3928 case GIMPLE_ASSIGN:
3929 {
3930 pre_expr result = NULL;
3931 switch (TREE_CODE_CLASS (gimple_assign_rhs_code (stmt)))
3932 {
3933 case tcc_unary:
3934 case tcc_binary:
3935 case tcc_comparison:
3936 {
3937 vn_nary_op_t nary;
3938 unsigned int i;
3939
3940 vn_nary_op_lookup_pieces (gimple_num_ops (stmt) - 1,
3941 gimple_assign_rhs_code (stmt),
3942 gimple_expr_type (stmt),
3943 gimple_assign_rhs1 (stmt),
3944 gimple_assign_rhs2 (stmt),
3945 NULL_TREE, NULL_TREE, &nary);
3946
3947 if (!nary)
3948 continue;
3949
3950 for (i = 0; i < nary->length; i++)
3951 if (TREE_CODE (nary->op[i]) == SSA_NAME)
3952 add_to_exp_gen (block, nary->op[i]);
3953
3954 result = (pre_expr) pool_alloc (pre_expr_pool);
3955 result->kind = NARY;
3956 result->id = 0;
3957 PRE_EXPR_NARY (result) = nary;
3958 break;
3959 }
3960
3961 case tcc_declaration:
3962 case tcc_reference:
3963 {
3964 vn_reference_t ref;
3965 unsigned int i;
3966 vn_reference_op_t vro;
3967
3968 vn_reference_lookup (gimple_assign_rhs1 (stmt),
3969 gimple_vuse (stmt),
3970 true, &ref);
3971 if (!ref)
3972 continue;
3973
3974 for (i = 0; VEC_iterate (vn_reference_op_s,
3975 ref->operands, i,
3976 vro); i++)
3977 {
3978 if (vro->op0 && TREE_CODE (vro->op0) == SSA_NAME)
3979 add_to_exp_gen (block, vro->op0);
3980 if (vro->op1 && TREE_CODE (vro->op1) == SSA_NAME)
3981 add_to_exp_gen (block, vro->op1);
3982 if (vro->op2 && TREE_CODE (vro->op2) == SSA_NAME)
3983 add_to_exp_gen (block, vro->op2);
3984 }
3985 result = (pre_expr) pool_alloc (pre_expr_pool);
3986 result->kind = REFERENCE;
3987 result->id = 0;
3988 PRE_EXPR_REFERENCE (result) = ref;
3989 break;
3990 }
3991
3992 default:
3993 /* For any other statement that we don't
3994 recognize, simply add all referenced
3995 SSA_NAMEs to EXP_GEN. */
3996 FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_USE)
3997 add_to_exp_gen (block, op);
3998 continue;
3999 }
4000
4001 get_or_alloc_expression_id (result);
4002 add_to_value (get_expr_value_id (result), result);
4003 if (!in_fre)
4004 bitmap_value_insert_into_set (EXP_GEN (block), result);
4005
4006 continue;
4007 }
4008 default:
4009 break;
4010 }
4011 }
4012
4013 /* Put the dominator children of BLOCK on the worklist of blocks
4014 to compute available sets for. */
4015 for (son = first_dom_son (CDI_DOMINATORS, block);
4016 son;
4017 son = next_dom_son (CDI_DOMINATORS, son))
4018 worklist[sp++] = son;
4019 }
4020
4021 free (worklist);
4022 }
4023
4024 /* Insert the expression for SSA_VN that SCCVN thought would be simpler
4025 than the available expressions for it. The insertion point is
4026 right before the first use in STMT. Returns the SSA_NAME that should
4027 be used for replacement. */
4028
4029 static tree
4030 do_SCCVN_insertion (gimple stmt, tree ssa_vn)
4031 {
4032 basic_block bb = gimple_bb (stmt);
4033 gimple_stmt_iterator gsi;
4034 gimple_seq stmts = NULL;
4035 tree expr;
4036 pre_expr e;
4037
4038 /* First create a value expression from the expression we want
4039 to insert and associate it with the value handle for SSA_VN. */
4040 e = get_or_alloc_expr_for (vn_get_expr_for (ssa_vn));
4041 if (e == NULL)
4042 return NULL_TREE;
4043
4044 /* Then use create_expression_by_pieces to generate a valid
4045 expression to insert at this point of the IL stream. */
4046 expr = create_expression_by_pieces (bb, e, &stmts, stmt, NULL);
4047 if (expr == NULL_TREE)
4048 return NULL_TREE;
4049 gsi = gsi_for_stmt (stmt);
4050 gsi_insert_seq_before (&gsi, stmts, GSI_SAME_STMT);
4051
4052 return expr;
4053 }
4054
4055 /* Eliminate fully redundant computations. */
4056
4057 static unsigned int
4058 eliminate (void)
4059 {
4060 VEC (gimple, heap) *to_remove = NULL;
4061 basic_block b;
4062 unsigned int todo = 0;
4063 gimple_stmt_iterator gsi;
4064 gimple stmt;
4065 unsigned i;
4066
4067 FOR_EACH_BB (b)
4068 {
4069 for (gsi = gsi_start_bb (b); !gsi_end_p (gsi); gsi_next (&gsi))
4070 {
4071 stmt = gsi_stmt (gsi);
4072
4073 /* Lookup the RHS of the expression, see if we have an
4074 available computation for it. If so, replace the RHS with
4075 the available computation. */
4076 if (gimple_has_lhs (stmt)
4077 && TREE_CODE (gimple_get_lhs (stmt)) == SSA_NAME
4078 && !gimple_assign_ssa_name_copy_p (stmt)
4079 && (!gimple_assign_single_p (stmt)
4080 || !is_gimple_min_invariant (gimple_assign_rhs1 (stmt)))
4081 && !gimple_has_volatile_ops (stmt)
4082 && !has_zero_uses (gimple_get_lhs (stmt)))
4083 {
4084 tree lhs = gimple_get_lhs (stmt);
4085 tree rhs = NULL_TREE;
4086 tree sprime = NULL;
4087 pre_expr lhsexpr = get_or_alloc_expr_for_name (lhs);
4088 pre_expr sprimeexpr;
4089
4090 if (gimple_assign_single_p (stmt))
4091 rhs = gimple_assign_rhs1 (stmt);
4092
4093 sprimeexpr = bitmap_find_leader (AVAIL_OUT (b),
4094 get_expr_value_id (lhsexpr),
4095 NULL);
4096
4097 if (sprimeexpr)
4098 {
4099 if (sprimeexpr->kind == CONSTANT)
4100 sprime = PRE_EXPR_CONSTANT (sprimeexpr);
4101 else if (sprimeexpr->kind == NAME)
4102 sprime = PRE_EXPR_NAME (sprimeexpr);
4103 else
4104 gcc_unreachable ();
4105 }
4106
4107 /* If there is no existing leader but SCCVN knows this
4108 value is constant, use that constant. */
4109 if (!sprime && is_gimple_min_invariant (VN_INFO (lhs)->valnum))
4110 {
4111 sprime = VN_INFO (lhs)->valnum;
4112 if (!useless_type_conversion_p (TREE_TYPE (lhs),
4113 TREE_TYPE (sprime)))
4114 sprime = fold_convert (TREE_TYPE (lhs), sprime);
4115
4116 if (dump_file && (dump_flags & TDF_DETAILS))
4117 {
4118 fprintf (dump_file, "Replaced ");
4119 print_gimple_expr (dump_file, stmt, 0, 0);
4120 fprintf (dump_file, " with ");
4121 print_generic_expr (dump_file, sprime, 0);
4122 fprintf (dump_file, " in ");
4123 print_gimple_stmt (dump_file, stmt, 0, 0);
4124 }
4125 pre_stats.eliminations++;
4126 propagate_tree_value_into_stmt (&gsi, sprime);
4127 stmt = gsi_stmt (gsi);
4128 update_stmt (stmt);
4129 continue;
4130 }
4131
4132 /* If there is no existing usable leader but SCCVN thinks
4133 it has an expression it wants to use as replacement,
4134 insert that. */
4135 if (!sprime || sprime == lhs)
4136 {
4137 tree val = VN_INFO (lhs)->valnum;
4138 if (val != VN_TOP
4139 && TREE_CODE (val) == SSA_NAME
4140 && VN_INFO (val)->needs_insertion
4141 && can_PRE_operation (vn_get_expr_for (val)))
4142 sprime = do_SCCVN_insertion (stmt, val);
4143 }
4144 if (sprime
4145 && sprime != lhs
4146 && (rhs == NULL_TREE
4147 || TREE_CODE (rhs) != SSA_NAME
4148 || may_propagate_copy (rhs, sprime)))
4149 {
4150 gcc_assert (sprime != rhs);
4151
4152 if (dump_file && (dump_flags & TDF_DETAILS))
4153 {
4154 fprintf (dump_file, "Replaced ");
4155 print_gimple_expr (dump_file, stmt, 0, 0);
4156 fprintf (dump_file, " with ");
4157 print_generic_expr (dump_file, sprime, 0);
4158 fprintf (dump_file, " in ");
4159 print_gimple_stmt (dump_file, stmt, 0, 0);
4160 }
4161
4162 if (TREE_CODE (sprime) == SSA_NAME)
4163 gimple_set_plf (SSA_NAME_DEF_STMT (sprime),
4164 NECESSARY, true);
4165 /* We need to make sure the new and old types actually match,
4166 which may require adding a simple cast, which fold_convert
4167 will do for us. */
4168 if ((!rhs || TREE_CODE (rhs) != SSA_NAME)
4169 && !useless_type_conversion_p (gimple_expr_type (stmt),
4170 TREE_TYPE (sprime)))
4171 sprime = fold_convert (gimple_expr_type (stmt), sprime);
4172
4173 pre_stats.eliminations++;
4174 propagate_tree_value_into_stmt (&gsi, sprime);
4175 stmt = gsi_stmt (gsi);
4176 update_stmt (stmt);
4177
4178 /* If we removed EH side effects from the statement, clean
4179 its EH information. */
4180 if (maybe_clean_or_replace_eh_stmt (stmt, stmt))
4181 {
4182 bitmap_set_bit (need_eh_cleanup,
4183 gimple_bb (stmt)->index);
4184 if (dump_file && (dump_flags & TDF_DETAILS))
4185 fprintf (dump_file, " Removed EH side effects.\n");
4186 }
4187 }
4188 }
4189 /* If the statement is a scalar store, see if the expression
4190 has the same value number as its rhs. If so, the store is
4191 dead. */
4192 else if (gimple_assign_single_p (stmt)
4193 && !is_gimple_reg (gimple_assign_lhs (stmt))
4194 && (TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME
4195 || is_gimple_min_invariant (gimple_assign_rhs1 (stmt))))
4196 {
4197 tree rhs = gimple_assign_rhs1 (stmt);
4198 tree val;
4199 val = vn_reference_lookup (gimple_assign_lhs (stmt),
4200 gimple_vuse (stmt), true, NULL);
4201 if (TREE_CODE (rhs) == SSA_NAME)
4202 rhs = VN_INFO (rhs)->valnum;
4203 if (val
4204 && operand_equal_p (val, rhs, 0))
4205 {
4206 if (dump_file && (dump_flags & TDF_DETAILS))
4207 {
4208 fprintf (dump_file, "Deleted redundant store ");
4209 print_gimple_stmt (dump_file, stmt, 0, 0);
4210 }
4211
4212 /* Queue stmt for removal. */
4213 VEC_safe_push (gimple, heap, to_remove, stmt);
4214 }
4215 }
4216 /* Visit COND_EXPRs and fold the comparison with the
4217 available value-numbers. */
4218 else if (gimple_code (stmt) == GIMPLE_COND)
4219 {
4220 tree op0 = gimple_cond_lhs (stmt);
4221 tree op1 = gimple_cond_rhs (stmt);
4222 tree result;
4223
4224 if (TREE_CODE (op0) == SSA_NAME)
4225 op0 = VN_INFO (op0)->valnum;
4226 if (TREE_CODE (op1) == SSA_NAME)
4227 op1 = VN_INFO (op1)->valnum;
4228 result = fold_binary (gimple_cond_code (stmt), boolean_type_node,
4229 op0, op1);
4230 if (result && TREE_CODE (result) == INTEGER_CST)
4231 {
4232 if (integer_zerop (result))
4233 gimple_cond_make_false (stmt);
4234 else
4235 gimple_cond_make_true (stmt);
4236 update_stmt (stmt);
4237 todo = TODO_cleanup_cfg;
4238 }
4239 }
4240 /* Visit indirect calls and turn them into direct calls if
4241 possible. */
4242 if (gimple_code (stmt) == GIMPLE_CALL
4243 && TREE_CODE (gimple_call_fn (stmt)) == SSA_NAME)
4244 {
4245 tree fn = VN_INFO (gimple_call_fn (stmt))->valnum;
4246 if (TREE_CODE (fn) == ADDR_EXPR
4247 && TREE_CODE (TREE_OPERAND (fn, 0)) == FUNCTION_DECL)
4248 {
4249 if (dump_file && (dump_flags & TDF_DETAILS))
4250 {
4251 fprintf (dump_file, "Replacing call target with ");
4252 print_generic_expr (dump_file, fn, 0);
4253 fprintf (dump_file, " in ");
4254 print_gimple_stmt (dump_file, stmt, 0, 0);
4255 }
4256
4257 gimple_call_set_fn (stmt, fn);
4258 update_stmt (stmt);
4259 if (maybe_clean_or_replace_eh_stmt (stmt, stmt))
4260 {
4261 bitmap_set_bit (need_eh_cleanup,
4262 gimple_bb (stmt)->index);
4263 if (dump_file && (dump_flags & TDF_DETAILS))
4264 fprintf (dump_file, " Removed EH side effects.\n");
4265 }
4266
4267 /* Changing an indirect call to a direct call may
4268 have exposed different semantics. This may
4269 require an SSA update. */
4270 todo |= TODO_update_ssa_only_virtuals;
4271 }
4272 }
4273 }
4274
4275 for (gsi = gsi_start_phis (b); !gsi_end_p (gsi);)
4276 {
4277 gimple stmt, phi = gsi_stmt (gsi);
4278 tree sprime = NULL_TREE, res = PHI_RESULT (phi);
4279 pre_expr sprimeexpr, resexpr;
4280 gimple_stmt_iterator gsi2;
4281
4282 /* We want to perform redundant PHI elimination. Do so by
4283 replacing the PHI with a single copy if possible.
4284 Do not touch inserted, single-argument or virtual PHIs. */
4285 if (gimple_phi_num_args (phi) == 1
4286 || !is_gimple_reg (res)
4287 || bitmap_bit_p (inserted_phi_names, SSA_NAME_VERSION (res)))
4288 {
4289 gsi_next (&gsi);
4290 continue;
4291 }
4292
4293 resexpr = get_or_alloc_expr_for_name (res);
4294 sprimeexpr = bitmap_find_leader (AVAIL_OUT (b),
4295 get_expr_value_id (resexpr), NULL);
4296 if (sprimeexpr)
4297 {
4298 if (sprimeexpr->kind == CONSTANT)
4299 sprime = PRE_EXPR_CONSTANT (sprimeexpr);
4300 else if (sprimeexpr->kind == NAME)
4301 sprime = PRE_EXPR_NAME (sprimeexpr);
4302 else
4303 gcc_unreachable ();
4304 }
4305 if (!sprimeexpr
4306 || sprime == res)
4307 {
4308 gsi_next (&gsi);
4309 continue;
4310 }
4311
4312 if (dump_file && (dump_flags & TDF_DETAILS))
4313 {
4314 fprintf (dump_file, "Replaced redundant PHI node defining ");
4315 print_generic_expr (dump_file, res, 0);
4316 fprintf (dump_file, " with ");
4317 print_generic_expr (dump_file, sprime, 0);
4318 fprintf (dump_file, "\n");
4319 }
4320
4321 remove_phi_node (&gsi, false);
4322
4323 if (!useless_type_conversion_p (TREE_TYPE (res), TREE_TYPE (sprime)))
4324 sprime = fold_convert (TREE_TYPE (res), sprime);
4325 stmt = gimple_build_assign (res, sprime);
4326 SSA_NAME_DEF_STMT (res) = stmt;
4327 if (TREE_CODE (sprime) == SSA_NAME)
4328 gimple_set_plf (SSA_NAME_DEF_STMT (sprime),
4329 NECESSARY, true);
4330 gsi2 = gsi_after_labels (b);
4331 gsi_insert_before (&gsi2, stmt, GSI_NEW_STMT);
4332 /* Queue the copy for eventual removal. */
4333 VEC_safe_push (gimple, heap, to_remove, stmt);
4334 pre_stats.eliminations++;
4335 }
4336 }
4337
4338 /* We cannot remove stmts during BB walk, especially not release SSA
4339 names there as this confuses the VN machinery. The stmts ending
4340 up in to_remove are either stores or simple copies. */
4341 for (i = 0; VEC_iterate (gimple, to_remove, i, stmt); ++i)
4342 {
4343 tree lhs = gimple_assign_lhs (stmt);
4344 use_operand_p use_p;
4345 gimple use_stmt;
4346
4347 /* If there is a single use only, propagate the equivalency
4348 instead of keeping the copy. */
4349 if (TREE_CODE (lhs) == SSA_NAME
4350 && single_imm_use (lhs, &use_p, &use_stmt)
4351 && may_propagate_copy (USE_FROM_PTR (use_p),
4352 gimple_assign_rhs1 (stmt)))
4353 {
4354 SET_USE (use_p, gimple_assign_rhs1 (stmt));
4355 update_stmt (use_stmt);
4356 }
4357
4358 /* If this is a store or a now unused copy, remove it. */
4359 if (TREE_CODE (lhs) != SSA_NAME
4360 || has_zero_uses (lhs))
4361 {
4362 gsi = gsi_for_stmt (stmt);
4363 unlink_stmt_vdef (stmt);
4364 gsi_remove (&gsi, true);
4365 release_defs (stmt);
4366 }
4367 }
4368 VEC_free (gimple, heap, to_remove);
4369
4370 return todo;
4371 }
4372
4373 /* Borrow a bit of tree-ssa-dce.c for the moment.
4374 XXX: In 4.1, we should be able to just run a DCE pass after PRE, though
4375 this may be a bit faster, and we may want critical edges kept split. */
4376
4377 /* If OP's defining statement has not already been determined to be necessary,
4378 mark that statement necessary. Return the stmt, if it is newly
4379 necessary. */
4380
4381 static inline gimple
4382 mark_operand_necessary (tree op)
4383 {
4384 gimple stmt;
4385
4386 gcc_assert (op);
4387
4388 if (TREE_CODE (op) != SSA_NAME)
4389 return NULL;
4390
4391 stmt = SSA_NAME_DEF_STMT (op);
4392 gcc_assert (stmt);
4393
4394 if (gimple_plf (stmt, NECESSARY)
4395 || gimple_nop_p (stmt))
4396 return NULL;
4397
4398 gimple_set_plf (stmt, NECESSARY, true);
4399 return stmt;
4400 }
4401
4402 /* Because we don't follow exactly the standard PRE algorithm, and decide not
4403 to insert PHI nodes sometimes, and because value numbering of casts isn't
4404 perfect, we sometimes end up inserting dead code. This simple DCE-like
4405 pass removes any insertions we made that weren't actually used. */
4406
4407 static void
4408 remove_dead_inserted_code (void)
4409 {
4410 VEC(gimple,heap) *worklist = NULL;
4411 int i;
4412 gimple t;
4413
4414 worklist = VEC_alloc (gimple, heap, VEC_length (gimple, inserted_exprs));
4415 for (i = 0; VEC_iterate (gimple, inserted_exprs, i, t); i++)
4416 {
4417 if (gimple_plf (t, NECESSARY))
4418 VEC_quick_push (gimple, worklist, t);
4419 }
4420 while (VEC_length (gimple, worklist) > 0)
4421 {
4422 t = VEC_pop (gimple, worklist);
4423
4424 /* PHI nodes are somewhat special in that each PHI alternative has
4425 data and control dependencies. All the statements feeding the
4426 PHI node's arguments are always necessary. */
4427 if (gimple_code (t) == GIMPLE_PHI)
4428 {
4429 unsigned k;
4430
4431 VEC_reserve (gimple, heap, worklist, gimple_phi_num_args (t));
4432 for (k = 0; k < gimple_phi_num_args (t); k++)
4433 {
4434 tree arg = PHI_ARG_DEF (t, k);
4435 if (TREE_CODE (arg) == SSA_NAME)
4436 {
4437 gimple n = mark_operand_necessary (arg);
4438 if (n)
4439 VEC_quick_push (gimple, worklist, n);
4440 }
4441 }
4442 }
4443 else
4444 {
4445 /* Propagate through the operands. Examine all the USE, VUSE and
4446 VDEF operands in this statement. Mark all the statements
4447 which feed this statement's uses as necessary. */
4448 ssa_op_iter iter;
4449 tree use;
4450
4451 /* The operands of VDEF expressions are also needed as they
4452 represent potential definitions that may reach this
4453 statement (VDEF operands allow us to follow def-def
4454 links). */
4455
4456 FOR_EACH_SSA_TREE_OPERAND (use, t, iter, SSA_OP_ALL_USES)
4457 {
4458 gimple n = mark_operand_necessary (use);
4459 if (n)
4460 VEC_safe_push (gimple, heap, worklist, n);
4461 }
4462 }
4463 }
4464
4465 for (i = 0; VEC_iterate (gimple, inserted_exprs, i, t); i++)
4466 {
4467 if (!gimple_plf (t, NECESSARY))
4468 {
4469 gimple_stmt_iterator gsi;
4470
4471 if (dump_file && (dump_flags & TDF_DETAILS))
4472 {
4473 fprintf (dump_file, "Removing unnecessary insertion:");
4474 print_gimple_stmt (dump_file, t, 0, 0);
4475 }
4476
4477 gsi = gsi_for_stmt (t);
4478 if (gimple_code (t) == GIMPLE_PHI)
4479 remove_phi_node (&gsi, true);
4480 else
4481 {
4482 gsi_remove (&gsi, true);
4483 release_defs (t);
4484 }
4485 }
4486 }
4487 VEC_free (gimple, heap, worklist);
4488 }
4489
4490 /* Compute a reverse post-order in *POST_ORDER. If INCLUDE_ENTRY_EXIT is
4491 true, then then ENTRY_BLOCK and EXIT_BLOCK are included. Returns
4492 the number of visited blocks. */
4493
4494 static int
4495 my_rev_post_order_compute (int *post_order, bool include_entry_exit)
4496 {
4497 edge_iterator *stack;
4498 int sp;
4499 int post_order_num = 0;
4500 sbitmap visited;
4501
4502 if (include_entry_exit)
4503 post_order[post_order_num++] = EXIT_BLOCK;
4504
4505 /* Allocate stack for back-tracking up CFG. */
4506 stack = XNEWVEC (edge_iterator, n_basic_blocks + 1);
4507 sp = 0;
4508
4509 /* Allocate bitmap to track nodes that have been visited. */
4510 visited = sbitmap_alloc (last_basic_block);
4511
4512 /* None of the nodes in the CFG have been visited yet. */
4513 sbitmap_zero (visited);
4514
4515 /* Push the last edge on to the stack. */
4516 stack[sp++] = ei_start (EXIT_BLOCK_PTR->preds);
4517
4518 while (sp)
4519 {
4520 edge_iterator ei;
4521 basic_block src;
4522 basic_block dest;
4523
4524 /* Look at the edge on the top of the stack. */
4525 ei = stack[sp - 1];
4526 src = ei_edge (ei)->src;
4527 dest = ei_edge (ei)->dest;
4528
4529 /* Check if the edge destination has been visited yet. */
4530 if (src != ENTRY_BLOCK_PTR && ! TEST_BIT (visited, src->index))
4531 {
4532 /* Mark that we have visited the destination. */
4533 SET_BIT (visited, src->index);
4534
4535 if (EDGE_COUNT (src->preds) > 0)
4536 /* Since the DEST node has been visited for the first
4537 time, check its successors. */
4538 stack[sp++] = ei_start (src->preds);
4539 else
4540 post_order[post_order_num++] = src->index;
4541 }
4542 else
4543 {
4544 if (ei_one_before_end_p (ei) && dest != EXIT_BLOCK_PTR)
4545 post_order[post_order_num++] = dest->index;
4546
4547 if (!ei_one_before_end_p (ei))
4548 ei_next (&stack[sp - 1]);
4549 else
4550 sp--;
4551 }
4552 }
4553
4554 if (include_entry_exit)
4555 post_order[post_order_num++] = ENTRY_BLOCK;
4556
4557 free (stack);
4558 sbitmap_free (visited);
4559 return post_order_num;
4560 }
4561
4562
4563 /* Initialize data structures used by PRE. */
4564
4565 static void
4566 init_pre (bool do_fre)
4567 {
4568 basic_block bb;
4569
4570 next_expression_id = 1;
4571 expressions = NULL;
4572 VEC_safe_push (pre_expr, heap, expressions, NULL);
4573 value_expressions = VEC_alloc (bitmap_set_t, heap, get_max_value_id () + 1);
4574 VEC_safe_grow_cleared (bitmap_set_t, heap, value_expressions,
4575 get_max_value_id() + 1);
4576 name_to_id = NULL;
4577
4578 in_fre = do_fre;
4579
4580 inserted_exprs = NULL;
4581 need_creation = NULL;
4582 pretemp = NULL_TREE;
4583 storetemp = NULL_TREE;
4584 prephitemp = NULL_TREE;
4585
4586 connect_infinite_loops_to_exit ();
4587 memset (&pre_stats, 0, sizeof (pre_stats));
4588
4589
4590 postorder = XNEWVEC (int, n_basic_blocks - NUM_FIXED_BLOCKS);
4591 my_rev_post_order_compute (postorder, false);
4592
4593 FOR_ALL_BB (bb)
4594 bb->aux = XCNEWVEC (struct bb_bitmap_sets, 1);
4595
4596 calculate_dominance_info (CDI_POST_DOMINATORS);
4597 calculate_dominance_info (CDI_DOMINATORS);
4598
4599 bitmap_obstack_initialize (&grand_bitmap_obstack);
4600 inserted_phi_names = BITMAP_ALLOC (&grand_bitmap_obstack);
4601 phi_translate_table = htab_create (5110, expr_pred_trans_hash,
4602 expr_pred_trans_eq, free);
4603 expression_to_id = htab_create (num_ssa_names * 3,
4604 pre_expr_hash,
4605 pre_expr_eq, NULL);
4606 bitmap_set_pool = create_alloc_pool ("Bitmap sets",
4607 sizeof (struct bitmap_set), 30);
4608 pre_expr_pool = create_alloc_pool ("pre_expr nodes",
4609 sizeof (struct pre_expr_d), 30);
4610 FOR_ALL_BB (bb)
4611 {
4612 EXP_GEN (bb) = bitmap_set_new ();
4613 PHI_GEN (bb) = bitmap_set_new ();
4614 TMP_GEN (bb) = bitmap_set_new ();
4615 AVAIL_OUT (bb) = bitmap_set_new ();
4616 }
4617
4618 need_eh_cleanup = BITMAP_ALLOC (NULL);
4619 }
4620
4621
4622 /* Deallocate data structures used by PRE. */
4623
4624 static void
4625 fini_pre (bool do_fre)
4626 {
4627 basic_block bb;
4628
4629 free (postorder);
4630 VEC_free (bitmap_set_t, heap, value_expressions);
4631 VEC_free (gimple, heap, inserted_exprs);
4632 VEC_free (gimple, heap, need_creation);
4633 bitmap_obstack_release (&grand_bitmap_obstack);
4634 free_alloc_pool (bitmap_set_pool);
4635 free_alloc_pool (pre_expr_pool);
4636 htab_delete (phi_translate_table);
4637 htab_delete (expression_to_id);
4638 VEC_free (unsigned, heap, name_to_id);
4639
4640 FOR_ALL_BB (bb)
4641 {
4642 free (bb->aux);
4643 bb->aux = NULL;
4644 }
4645
4646 free_dominance_info (CDI_POST_DOMINATORS);
4647
4648 if (!bitmap_empty_p (need_eh_cleanup))
4649 {
4650 gimple_purge_all_dead_eh_edges (need_eh_cleanup);
4651 cleanup_tree_cfg ();
4652 }
4653
4654 BITMAP_FREE (need_eh_cleanup);
4655
4656 if (!do_fre)
4657 loop_optimizer_finalize ();
4658 }
4659
4660 /* Main entry point to the SSA-PRE pass. DO_FRE is true if the caller
4661 only wants to do full redundancy elimination. */
4662
4663 static unsigned int
4664 execute_pre (bool do_fre)
4665 {
4666 unsigned int todo = 0;
4667
4668 do_partial_partial = optimize > 2 && optimize_function_for_speed_p (cfun);
4669
4670 /* This has to happen before SCCVN runs because
4671 loop_optimizer_init may create new phis, etc. */
4672 if (!do_fre)
4673 loop_optimizer_init (LOOPS_NORMAL);
4674
4675 if (!run_scc_vn (do_fre))
4676 {
4677 if (!do_fre)
4678 {
4679 remove_dead_inserted_code ();
4680 loop_optimizer_finalize ();
4681 }
4682
4683 return 0;
4684 }
4685 init_pre (do_fre);
4686 scev_initialize ();
4687
4688
4689 /* Collect and value number expressions computed in each basic block. */
4690 compute_avail ();
4691
4692 if (dump_file && (dump_flags & TDF_DETAILS))
4693 {
4694 basic_block bb;
4695
4696 FOR_ALL_BB (bb)
4697 {
4698 print_bitmap_set (dump_file, EXP_GEN (bb), "exp_gen", bb->index);
4699 print_bitmap_set (dump_file, PHI_GEN (bb), "phi_gen", bb->index);
4700 print_bitmap_set (dump_file, TMP_GEN (bb), "tmp_gen", bb->index);
4701 print_bitmap_set (dump_file, AVAIL_OUT (bb), "avail_out", bb->index);
4702 }
4703 }
4704
4705 /* Insert can get quite slow on an incredibly large number of basic
4706 blocks due to some quadratic behavior. Until this behavior is
4707 fixed, don't run it when he have an incredibly large number of
4708 bb's. If we aren't going to run insert, there is no point in
4709 computing ANTIC, either, even though it's plenty fast. */
4710 if (!do_fre && n_basic_blocks < 4000)
4711 {
4712 compute_antic ();
4713 insert ();
4714 }
4715
4716 /* Remove all the redundant expressions. */
4717 todo |= eliminate ();
4718
4719 statistics_counter_event (cfun, "Insertions", pre_stats.insertions);
4720 statistics_counter_event (cfun, "PA inserted", pre_stats.pa_insert);
4721 statistics_counter_event (cfun, "New PHIs", pre_stats.phis);
4722 statistics_counter_event (cfun, "Eliminated", pre_stats.eliminations);
4723 statistics_counter_event (cfun, "Constified", pre_stats.constified);
4724
4725 /* Make sure to remove fake edges before committing our inserts.
4726 This makes sure we don't end up with extra critical edges that
4727 we would need to split. */
4728 remove_fake_exit_edges ();
4729 gsi_commit_edge_inserts ();
4730
4731 clear_expression_ids ();
4732 free_scc_vn ();
4733 if (!do_fre)
4734 remove_dead_inserted_code ();
4735
4736 scev_finalize ();
4737 fini_pre (do_fre);
4738
4739 return todo;
4740 }
4741
4742 /* Gate and execute functions for PRE. */
4743
4744 static unsigned int
4745 do_pre (void)
4746 {
4747 return execute_pre (false);
4748 }
4749
4750 static bool
4751 gate_pre (void)
4752 {
4753 return flag_tree_pre != 0;
4754 }
4755
4756 struct gimple_opt_pass pass_pre =
4757 {
4758 {
4759 GIMPLE_PASS,
4760 "pre", /* name */
4761 gate_pre, /* gate */
4762 do_pre, /* execute */
4763 NULL, /* sub */
4764 NULL, /* next */
4765 0, /* static_pass_number */
4766 TV_TREE_PRE, /* tv_id */
4767 PROP_no_crit_edges | PROP_cfg
4768 | PROP_ssa, /* properties_required */
4769 0, /* properties_provided */
4770 0, /* properties_destroyed */
4771 TODO_rebuild_alias, /* todo_flags_start */
4772 TODO_update_ssa_only_virtuals | TODO_dump_func | TODO_ggc_collect
4773 | TODO_verify_ssa /* todo_flags_finish */
4774 }
4775 };
4776
4777
4778 /* Gate and execute functions for FRE. */
4779
4780 static unsigned int
4781 execute_fre (void)
4782 {
4783 return execute_pre (true);
4784 }
4785
4786 static bool
4787 gate_fre (void)
4788 {
4789 return flag_tree_fre != 0;
4790 }
4791
4792 struct gimple_opt_pass pass_fre =
4793 {
4794 {
4795 GIMPLE_PASS,
4796 "fre", /* name */
4797 gate_fre, /* gate */
4798 execute_fre, /* execute */
4799 NULL, /* sub */
4800 NULL, /* next */
4801 0, /* static_pass_number */
4802 TV_TREE_FRE, /* tv_id */
4803 PROP_cfg | PROP_ssa, /* properties_required */
4804 0, /* properties_provided */
4805 0, /* properties_destroyed */
4806 0, /* todo_flags_start */
4807 TODO_dump_func | TODO_ggc_collect | TODO_verify_ssa /* todo_flags_finish */
4808 }
4809 };