Merge branch 'vendor/GCC44'
[dragonfly.git] / contrib / gcc-4.4 / gcc / tree-ssa-operands.c
CommitLineData
c251ad9e
SS
1/* SSA operands management for trees.
2 Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008
3 Free Software Foundation, Inc.
4
5This file is part of GCC.
6
7GCC is free software; you can redistribute it and/or modify
8it under the terms of the GNU General Public License as published by
9the Free Software Foundation; either version 3, or (at your option)
10any later version.
11
12GCC is distributed in the hope that it will be useful,
13but WITHOUT ANY WARRANTY; without even the implied warranty of
14MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15GNU General Public License for more details.
16
17You should have received a copy of the GNU General Public License
18along with GCC; see the file COPYING3. If not see
19<http://www.gnu.org/licenses/>. */
20
21#include "config.h"
22#include "system.h"
23#include "coretypes.h"
24#include "tm.h"
25#include "tree.h"
26#include "flags.h"
27#include "function.h"
28#include "diagnostic.h"
29#include "tree-flow.h"
30#include "tree-inline.h"
31#include "tree-pass.h"
32#include "ggc.h"
33#include "timevar.h"
34#include "toplev.h"
35#include "langhooks.h"
36#include "ipa-reference.h"
37
38/* This file contains the code required to manage the operands cache of the
39 SSA optimizer. For every stmt, we maintain an operand cache in the stmt
40 annotation. This cache contains operands that will be of interest to
41 optimizers and other passes wishing to manipulate the IL.
42
43 The operand type are broken up into REAL and VIRTUAL operands. The real
44 operands are represented as pointers into the stmt's operand tree. Thus
45 any manipulation of the real operands will be reflected in the actual tree.
46 Virtual operands are represented solely in the cache, although the base
47 variable for the SSA_NAME may, or may not occur in the stmt's tree.
48 Manipulation of the virtual operands will not be reflected in the stmt tree.
49
50 The routines in this file are concerned with creating this operand cache
51 from a stmt tree.
52
53 The operand tree is the parsed by the various get_* routines which look
54 through the stmt tree for the occurrence of operands which may be of
55 interest, and calls are made to the append_* routines whenever one is
56 found. There are 4 of these routines, each representing one of the
57 4 types of operands. Defs, Uses, Virtual Uses, and Virtual May Defs.
58
59 The append_* routines check for duplication, and simply keep a list of
60 unique objects for each operand type in the build_* extendable vectors.
61
62 Once the stmt tree is completely parsed, the finalize_ssa_operands()
63 routine is called, which proceeds to perform the finalization routine
64 on each of the 4 operand vectors which have been built up.
65
66 If the stmt had a previous operand cache, the finalization routines
67 attempt to match up the new operands with the old ones. If it's a perfect
68 match, the old vector is simply reused. If it isn't a perfect match, then
69 a new vector is created and the new operands are placed there. For
70 virtual operands, if the previous cache had SSA_NAME version of a
71 variable, and that same variable occurs in the same operands cache, then
72 the new cache vector will also get the same SSA_NAME.
73
74 i.e., if a stmt had a VUSE of 'a_5', and 'a' occurs in the new
75 operand vector for VUSE, then the new vector will also be modified
76 such that it contains 'a_5' rather than 'a'. */
77
78/* Helper functions from gimple.c. These are GIMPLE manipulation
79 routines that only the operand scanner should need. */
80void gimple_set_stored_syms (gimple, bitmap, bitmap_obstack *);
81void gimple_set_loaded_syms (gimple, bitmap, bitmap_obstack *);
82
83/* Structure storing statistics on how many call clobbers we have, and
84 how many where avoided. */
85
86static struct
87{
88 /* Number of call-clobbered ops we attempt to add to calls in
89 add_call_clobbered_mem_symbols. */
90 unsigned int clobbered_vars;
91
92 /* Number of write-clobbers (VDEFs) avoided by using
93 not_written information. */
94 unsigned int static_write_clobbers_avoided;
95
96 /* Number of reads (VUSEs) avoided by using not_read information. */
97 unsigned int static_read_clobbers_avoided;
98
99 /* Number of write-clobbers avoided because the variable can't escape to
100 this call. */
101 unsigned int unescapable_clobbers_avoided;
102
103 /* Number of read-only uses we attempt to add to calls in
104 add_call_read_mem_symbols. */
105 unsigned int readonly_clobbers;
106
107 /* Number of read-only uses we avoid using not_read information. */
108 unsigned int static_readonly_clobbers_avoided;
109} clobber_stats;
110
111
112/* Flags to describe operand properties in helpers. */
113
114/* By default, operands are loaded. */
115#define opf_use 0
116
117/* Operand is the target of an assignment expression or a
118 call-clobbered variable. */
119#define opf_def (1 << 0)
120
121/* No virtual operands should be created in the expression. This is used
122 when traversing ADDR_EXPR nodes which have different semantics than
123 other expressions. Inside an ADDR_EXPR node, the only operands that we
124 need to consider are indices into arrays. For instance, &a.b[i] should
125 generate a USE of 'i' but it should not generate a VUSE for 'a' nor a
126 VUSE for 'b'. */
127#define opf_no_vops (1 << 1)
128
129/* Operand is an implicit reference. This is used to distinguish
130 explicit assignments in the form of MODIFY_EXPR from
131 clobbering sites like function calls or ASM_EXPRs. */
132#define opf_implicit (1 << 2)
133
134/* Array for building all the def operands. */
135static VEC(tree,heap) *build_defs;
136
137/* Array for building all the use operands. */
138static VEC(tree,heap) *build_uses;
139
140/* Set for building all the VDEF operands. */
141static VEC(tree,heap) *build_vdefs;
142
143/* Set for building all the VUSE operands. */
144static VEC(tree,heap) *build_vuses;
145
146/* Bitmap obstack for our datastructures that needs to survive across
147 compilations of multiple functions. */
148static bitmap_obstack operands_bitmap_obstack;
149
150/* Set for building all the loaded symbols. */
151static bitmap build_loads;
152
153/* Set for building all the stored symbols. */
154static bitmap build_stores;
155
156static void get_expr_operands (gimple, tree *, int);
157
158/* Number of functions with initialized ssa_operands. */
159static int n_initialized = 0;
160
161/* Statement change buffer. Data structure used to record state
162 information for statements. This is used to determine what needs
163 to be done in order to update the SSA web after a statement is
164 modified by a pass. If STMT is a statement that has just been
165 created, or needs to be folded via fold_stmt, or anything that
166 changes its physical structure then the pass should:
167
168 1- Call push_stmt_changes (&stmt) to record the current state of
169 STMT before any modifications are made.
170
171 2- Make all appropriate modifications to the statement.
172
173 3- Call pop_stmt_changes (&stmt) to find new symbols that
174 need to be put in SSA form, SSA name mappings for names that
175 have disappeared, recompute invariantness for address
176 expressions, cleanup EH information, etc.
177
178 If it is possible to determine that the statement was not modified,
179 instead of calling pop_stmt_changes it is quicker to call
180 discard_stmt_changes to avoid the expensive and unnecessary operand
181 re-scan and change comparison. */
182
183struct scb_d
184{
185 /* Pointer to the statement being modified. */
186 gimple *stmt_p;
187
188 /* If the statement references memory these are the sets of symbols
189 loaded and stored by the statement. */
190 bitmap loads;
191 bitmap stores;
192};
193
194typedef struct scb_d *scb_t;
195DEF_VEC_P(scb_t);
196DEF_VEC_ALLOC_P(scb_t,heap);
197
198/* Stack of statement change buffers (SCB). Every call to
199 push_stmt_changes pushes a new buffer onto the stack. Calls to
200 pop_stmt_changes pop a buffer off of the stack and compute the set
201 of changes for the popped statement. */
202static VEC(scb_t,heap) *scb_stack;
203
204/* Return the DECL_UID of the base variable of T. */
205
206static inline unsigned
207get_name_decl (const_tree t)
208{
209 if (TREE_CODE (t) != SSA_NAME)
210 return DECL_UID (t);
211 else
212 return DECL_UID (SSA_NAME_VAR (t));
213}
214
215
216/* Comparison function for qsort used in operand_build_sort_virtual. */
217
218int
219operand_build_cmp (const void *p, const void *q)
220{
221 const_tree const e1 = *((const_tree const *)p);
222 const_tree const e2 = *((const_tree const *)q);
223 const unsigned int u1 = get_name_decl (e1);
224 const unsigned int u2 = get_name_decl (e2);
225
226 /* We want to sort in ascending order. They can never be equal. */
227#ifdef ENABLE_CHECKING
228 gcc_assert (u1 != u2);
229#endif
230 return (u1 > u2 ? 1 : -1);
231}
232
233
234/* Sort the virtual operands in LIST from lowest DECL_UID to highest. */
235
236static inline void
237operand_build_sort_virtual (VEC(tree,heap) *list)
238{
239 int num = VEC_length (tree, list);
240
241 if (num < 2)
242 return;
243
244 if (num == 2)
245 {
246 if (get_name_decl (VEC_index (tree, list, 0))
247 > get_name_decl (VEC_index (tree, list, 1)))
248 {
249 /* Swap elements if in the wrong order. */
250 tree tmp = VEC_index (tree, list, 0);
251 VEC_replace (tree, list, 0, VEC_index (tree, list, 1));
252 VEC_replace (tree, list, 1, tmp);
253 }
254 return;
255 }
256
257 /* There are 3 or more elements, call qsort. */
258 qsort (VEC_address (tree, list),
259 VEC_length (tree, list),
260 sizeof (tree),
261 operand_build_cmp);
262}
263
264/* Return true if the SSA operands cache is active. */
265
266bool
267ssa_operands_active (void)
268{
269 /* This function may be invoked from contexts where CFUN is NULL
270 (IPA passes), return false for now. FIXME: operands may be
271 active in each individual function, maybe this function should
272 take CFUN as a parameter. */
273 if (cfun == NULL)
274 return false;
275
276 return cfun->gimple_df && gimple_ssa_operands (cfun)->ops_active;
277}
278
279
280/* VOPs are of variable sized, so the free list maps "free buckets" to the
281 following table:
282 bucket # operands
283 ------ ----------
284 0 1
285 1 2
286 ...
287 15 16
288 16 17-24
289 17 25-32
290 18 31-40
291 ...
292 29 121-128
293 Any VOPs larger than this are simply added to the largest bucket when they
294 are freed. */
295
296
297/* Return the number of operands used in bucket BUCKET. */
298
299static inline int
300vop_free_bucket_size (int bucket)
301{
302#ifdef ENABLE_CHECKING
303 gcc_assert (bucket >= 0 && bucket < NUM_VOP_FREE_BUCKETS);
304#endif
305 if (bucket < 16)
306 return bucket + 1;
307 return (bucket - 13) * 8;
308}
309
310
311/* For a vop of NUM operands, return the bucket NUM belongs to. If NUM is
312 beyond the end of the bucket table, return -1. */
313
314static inline int
315vop_free_bucket_index (int num)
316{
317 gcc_assert (num > 0 && NUM_VOP_FREE_BUCKETS > 16);
318
319 /* Sizes 1 through 16 use buckets 0-15. */
320 if (num <= 16)
321 return num - 1;
322 /* Buckets 16 - NUM_VOP_FREE_BUCKETS represent 8 unit chunks. */
323 num = 14 + (num - 1) / 8;
324 if (num >= NUM_VOP_FREE_BUCKETS)
325 return -1;
326 else
327 return num;
328}
329
330
331/* Initialize the VOP free buckets. */
332
333static inline void
334init_vop_buckets (void)
335{
336 int x;
337
338 for (x = 0; x < NUM_VOP_FREE_BUCKETS; x++)
339 gimple_ssa_operands (cfun)->vop_free_buckets[x] = NULL;
340}
341
342
343/* Add PTR to the appropriate VOP bucket. */
344
345static inline void
346add_vop_to_freelist (voptype_p ptr)
347{
348 int bucket = vop_free_bucket_index (VUSE_VECT_NUM_ELEM (ptr->usev));
349
350 /* Too large, use the largest bucket so its not a complete throw away. */
351 if (bucket == -1)
352 bucket = NUM_VOP_FREE_BUCKETS - 1;
353
354 ptr->next = gimple_ssa_operands (cfun)->vop_free_buckets[bucket];
355 gimple_ssa_operands (cfun)->vop_free_buckets[bucket] = ptr;
356}
357
358
359/* These are the sizes of the operand memory buffer which gets allocated each
360 time more operands space is required. The final value is the amount that is
361 allocated every time after that. */
362
363#define OP_SIZE_INIT 0
364#define OP_SIZE_1 30
365#define OP_SIZE_2 110
366#define OP_SIZE_3 511
367
368/* Initialize the operand cache routines. */
369
370void
371init_ssa_operands (void)
372{
373 if (!n_initialized++)
374 {
375 build_defs = VEC_alloc (tree, heap, 5);
376 build_uses = VEC_alloc (tree, heap, 10);
377 build_vuses = VEC_alloc (tree, heap, 25);
378 build_vdefs = VEC_alloc (tree, heap, 25);
379 bitmap_obstack_initialize (&operands_bitmap_obstack);
380 build_loads = BITMAP_ALLOC (&operands_bitmap_obstack);
381 build_stores = BITMAP_ALLOC (&operands_bitmap_obstack);
382 scb_stack = VEC_alloc (scb_t, heap, 20);
383 }
384
385 gcc_assert (gimple_ssa_operands (cfun)->operand_memory == NULL);
386 gcc_assert (gimple_ssa_operands (cfun)->mpt_table == NULL);
387 gimple_ssa_operands (cfun)->operand_memory_index
388 = gimple_ssa_operands (cfun)->ssa_operand_mem_size;
389 gimple_ssa_operands (cfun)->ops_active = true;
390 memset (&clobber_stats, 0, sizeof (clobber_stats));
391 init_vop_buckets ();
392 gimple_ssa_operands (cfun)->ssa_operand_mem_size = OP_SIZE_INIT;
393}
394
395
396/* Dispose of anything required by the operand routines. */
397
398void
399fini_ssa_operands (void)
400{
401 struct ssa_operand_memory_d *ptr;
402 unsigned ix;
403 tree mpt;
404
405 if (!--n_initialized)
406 {
407 VEC_free (tree, heap, build_defs);
408 VEC_free (tree, heap, build_uses);
409 VEC_free (tree, heap, build_vdefs);
410 VEC_free (tree, heap, build_vuses);
411 BITMAP_FREE (build_loads);
412 BITMAP_FREE (build_stores);
413
414 /* The change buffer stack had better be empty. */
415 gcc_assert (VEC_length (scb_t, scb_stack) == 0);
416 VEC_free (scb_t, heap, scb_stack);
417 scb_stack = NULL;
418 }
419
420 gimple_ssa_operands (cfun)->free_defs = NULL;
421 gimple_ssa_operands (cfun)->free_uses = NULL;
422
423 while ((ptr = gimple_ssa_operands (cfun)->operand_memory) != NULL)
424 {
425 gimple_ssa_operands (cfun)->operand_memory
426 = gimple_ssa_operands (cfun)->operand_memory->next;
427 ggc_free (ptr);
428 }
429
430 for (ix = 0;
431 VEC_iterate (tree, gimple_ssa_operands (cfun)->mpt_table, ix, mpt);
432 ix++)
433 {
434 if (mpt)
435 BITMAP_FREE (MPT_SYMBOLS (mpt));
436 }
437
438 VEC_free (tree, heap, gimple_ssa_operands (cfun)->mpt_table);
439
440 gimple_ssa_operands (cfun)->ops_active = false;
441
442 if (!n_initialized)
443 bitmap_obstack_release (&operands_bitmap_obstack);
444
445 if (dump_file && (dump_flags & TDF_STATS))
446 {
447 fprintf (dump_file, "Original clobbered vars: %d\n",
448 clobber_stats.clobbered_vars);
449 fprintf (dump_file, "Static write clobbers avoided: %d\n",
450 clobber_stats.static_write_clobbers_avoided);
451 fprintf (dump_file, "Static read clobbers avoided: %d\n",
452 clobber_stats.static_read_clobbers_avoided);
453 fprintf (dump_file, "Unescapable clobbers avoided: %d\n",
454 clobber_stats.unescapable_clobbers_avoided);
455 fprintf (dump_file, "Original read-only clobbers: %d\n",
456 clobber_stats.readonly_clobbers);
457 fprintf (dump_file, "Static read-only clobbers avoided: %d\n",
458 clobber_stats.static_readonly_clobbers_avoided);
459 }
460}
461
462
463/* Return memory for operands of SIZE chunks. */
464
465static inline void *
466ssa_operand_alloc (unsigned size)
467{
468 char *ptr;
469
470 if (gimple_ssa_operands (cfun)->operand_memory_index + size
471 >= gimple_ssa_operands (cfun)->ssa_operand_mem_size)
472 {
473 struct ssa_operand_memory_d *ptr;
474
475 if (gimple_ssa_operands (cfun)->ssa_operand_mem_size == OP_SIZE_INIT)
476 gimple_ssa_operands (cfun)->ssa_operand_mem_size
477 = OP_SIZE_1 * sizeof (struct voptype_d);
478 else
479 if (gimple_ssa_operands (cfun)->ssa_operand_mem_size
480 == OP_SIZE_1 * sizeof (struct voptype_d))
481 gimple_ssa_operands (cfun)->ssa_operand_mem_size
482 = OP_SIZE_2 * sizeof (struct voptype_d);
483 else
484 gimple_ssa_operands (cfun)->ssa_operand_mem_size
485 = OP_SIZE_3 * sizeof (struct voptype_d);
486
487 /* Go right to the maximum size if the request is too large. */
488 if (size > gimple_ssa_operands (cfun)->ssa_operand_mem_size)
489 gimple_ssa_operands (cfun)->ssa_operand_mem_size
490 = OP_SIZE_3 * sizeof (struct voptype_d);
491
492 /* We can reliably trigger the case that we need arbitrary many
493 operands (see PR34093), so allocate a buffer just for this request. */
494 if (size > gimple_ssa_operands (cfun)->ssa_operand_mem_size)
495 gimple_ssa_operands (cfun)->ssa_operand_mem_size = size;
496
497 ptr = (struct ssa_operand_memory_d *)
498 ggc_alloc (sizeof (struct ssa_operand_memory_d)
499 + gimple_ssa_operands (cfun)->ssa_operand_mem_size - 1);
500 ptr->next = gimple_ssa_operands (cfun)->operand_memory;
501 gimple_ssa_operands (cfun)->operand_memory = ptr;
502 gimple_ssa_operands (cfun)->operand_memory_index = 0;
503 }
504 ptr = &(gimple_ssa_operands (cfun)->operand_memory
505 ->mem[gimple_ssa_operands (cfun)->operand_memory_index]);
506 gimple_ssa_operands (cfun)->operand_memory_index += size;
507 return ptr;
508}
509
510
511/* Allocate a DEF operand. */
512
513static inline struct def_optype_d *
514alloc_def (void)
515{
516 struct def_optype_d *ret;
517 if (gimple_ssa_operands (cfun)->free_defs)
518 {
519 ret = gimple_ssa_operands (cfun)->free_defs;
520 gimple_ssa_operands (cfun)->free_defs
521 = gimple_ssa_operands (cfun)->free_defs->next;
522 }
523 else
524 ret = (struct def_optype_d *)
525 ssa_operand_alloc (sizeof (struct def_optype_d));
526 return ret;
527}
528
529
530/* Allocate a USE operand. */
531
532static inline struct use_optype_d *
533alloc_use (void)
534{
535 struct use_optype_d *ret;
536 if (gimple_ssa_operands (cfun)->free_uses)
537 {
538 ret = gimple_ssa_operands (cfun)->free_uses;
539 gimple_ssa_operands (cfun)->free_uses
540 = gimple_ssa_operands (cfun)->free_uses->next;
541 }
542 else
543 ret = (struct use_optype_d *)
544 ssa_operand_alloc (sizeof (struct use_optype_d));
545 return ret;
546}
547
548
549/* Allocate a vop with NUM elements. */
550
551static inline struct voptype_d *
552alloc_vop (int num)
553{
554 struct voptype_d *ret = NULL;
555 int alloc_size = 0;
556
557 int bucket = vop_free_bucket_index (num);
558 if (bucket != -1)
559 {
560 /* If there is a free operand, use it. */
561 if (gimple_ssa_operands (cfun)->vop_free_buckets[bucket] != NULL)
562 {
563 ret = gimple_ssa_operands (cfun)->vop_free_buckets[bucket];
564 gimple_ssa_operands (cfun)->vop_free_buckets[bucket] =
565 gimple_ssa_operands (cfun)->vop_free_buckets[bucket]->next;
566 }
567 else
568 alloc_size = vop_free_bucket_size(bucket);
569 }
570 else
571 alloc_size = num;
572
573 if (alloc_size > 0)
574 ret = (struct voptype_d *)ssa_operand_alloc (
575 sizeof (struct voptype_d) + (alloc_size - 1) * sizeof (vuse_element_t));
576
577 VUSE_VECT_NUM_ELEM (ret->usev) = num;
578 return ret;
579}
580
581
582/* This routine makes sure that PTR is in an immediate use list, and makes
583 sure the stmt pointer is set to the current stmt. */
584
585static inline void
586set_virtual_use_link (use_operand_p ptr, gimple stmt)
587{
588 /* fold_stmt may have changed the stmt pointers. */
589 if (ptr->loc.stmt != stmt)
590 ptr->loc.stmt = stmt;
591
592 /* If this use isn't in a list, add it to the correct list. */
593 if (!ptr->prev)
594 link_imm_use (ptr, *(ptr->use));
595}
596
597
598/* Adds OP to the list of defs after LAST. */
599
600static inline def_optype_p
601add_def_op (tree *op, def_optype_p last)
602{
603 def_optype_p new_def;
604
605 new_def = alloc_def ();
606 DEF_OP_PTR (new_def) = op;
607 last->next = new_def;
608 new_def->next = NULL;
609 return new_def;
610}
611
612
613/* Adds OP to the list of uses of statement STMT after LAST. */
614
615static inline use_optype_p
616add_use_op (gimple stmt, tree *op, use_optype_p last)
617{
618 use_optype_p new_use;
619
620 new_use = alloc_use ();
621 USE_OP_PTR (new_use)->use = op;
622 link_imm_use_stmt (USE_OP_PTR (new_use), *op, stmt);
623 last->next = new_use;
624 new_use->next = NULL;
625 return new_use;
626}
627
628
629/* Return a virtual op pointer with NUM elements which are all
630 initialized to OP and are linked into the immediate uses for STMT.
631 The new vop is appended after PREV. */
632
633static inline voptype_p
634add_vop (gimple stmt, tree op, int num, voptype_p prev)
635{
636 voptype_p new_vop;
637 int x;
638
639 new_vop = alloc_vop (num);
640 for (x = 0; x < num; x++)
641 {
642 VUSE_OP_PTR (new_vop, x)->prev = NULL;
643 SET_VUSE_OP (new_vop, x, op);
644 VUSE_OP_PTR (new_vop, x)->use = &new_vop->usev.uses[x].use_var;
645 link_imm_use_stmt (VUSE_OP_PTR (new_vop, x),
646 new_vop->usev.uses[x].use_var, stmt);
647 }
648
649 if (prev)
650 prev->next = new_vop;
651 new_vop->next = NULL;
652 return new_vop;
653}
654
655
656/* Adds OP to the list of vuses of statement STMT after LAST, and moves
657 LAST to the new element. */
658
659static inline voptype_p
660add_vuse_op (gimple stmt, tree op, int num, voptype_p last)
661{
662 voptype_p new_vop = add_vop (stmt, op, num, last);
663 VDEF_RESULT (new_vop) = NULL_TREE;
664 return new_vop;
665}
666
667
668/* Adds OP to the list of vdefs of statement STMT after LAST, and moves
669 LAST to the new element. */
670
671static inline voptype_p
672add_vdef_op (gimple stmt, tree op, int num, voptype_p last)
673{
674 voptype_p new_vop = add_vop (stmt, op, num, last);
675 VDEF_RESULT (new_vop) = op;
676 return new_vop;
677}
678
679
680/* Takes elements from build_defs and turns them into def operands of STMT.
681 TODO -- Make build_defs VEC of tree *. */
682
683static inline void
684finalize_ssa_defs (gimple stmt)
685{
686 unsigned new_i;
687 struct def_optype_d new_list;
688 def_optype_p old_ops, last;
689 unsigned int num = VEC_length (tree, build_defs);
690
691 /* There should only be a single real definition per assignment. */
692 gcc_assert ((stmt && gimple_code (stmt) != GIMPLE_ASSIGN) || num <= 1);
693
694 new_list.next = NULL;
695 last = &new_list;
696
697 old_ops = gimple_def_ops (stmt);
698
699 new_i = 0;
700
701 /* Check for the common case of 1 def that hasn't changed. */
702 if (old_ops && old_ops->next == NULL && num == 1
703 && (tree *) VEC_index (tree, build_defs, 0) == DEF_OP_PTR (old_ops))
704 return;
705
706 /* If there is anything in the old list, free it. */
707 if (old_ops)
708 {
709 old_ops->next = gimple_ssa_operands (cfun)->free_defs;
710 gimple_ssa_operands (cfun)->free_defs = old_ops;
711 }
712
713 /* If there is anything remaining in the build_defs list, simply emit it. */
714 for ( ; new_i < num; new_i++)
715 last = add_def_op ((tree *) VEC_index (tree, build_defs, new_i), last);
716
717 /* Now set the stmt's operands. */
718 gimple_set_def_ops (stmt, new_list.next);
719
720#ifdef ENABLE_CHECKING
721 {
722 def_optype_p ptr;
723 unsigned x = 0;
724 for (ptr = gimple_def_ops (stmt); ptr; ptr = ptr->next)
725 x++;
726
727 gcc_assert (x == num);
728 }
729#endif
730}
731
732
733/* Takes elements from build_uses and turns them into use operands of STMT.
734 TODO -- Make build_uses VEC of tree *. */
735
736static inline void
737finalize_ssa_uses (gimple stmt)
738{
739 unsigned new_i;
740 struct use_optype_d new_list;
741 use_optype_p old_ops, ptr, last;
742
743 new_list.next = NULL;
744 last = &new_list;
745
746 old_ops = gimple_use_ops (stmt);
747
748 /* If there is anything in the old list, free it. */
749 if (old_ops)
750 {
751 for (ptr = old_ops; ptr; ptr = ptr->next)
752 delink_imm_use (USE_OP_PTR (ptr));
753 old_ops->next = gimple_ssa_operands (cfun)->free_uses;
754 gimple_ssa_operands (cfun)->free_uses = old_ops;
755 }
756
757 /* Now create nodes for all the new nodes. */
758 for (new_i = 0; new_i < VEC_length (tree, build_uses); new_i++)
759 last = add_use_op (stmt,
760 (tree *) VEC_index (tree, build_uses, new_i),
761 last);
762
763 /* Now set the stmt's operands. */
764 gimple_set_use_ops (stmt, new_list.next);
765
766#ifdef ENABLE_CHECKING
767 {
768 unsigned x = 0;
769 for (ptr = gimple_use_ops (stmt); ptr; ptr = ptr->next)
770 x++;
771
772 gcc_assert (x == VEC_length (tree, build_uses));
773 }
774#endif
775}
776
777
778/* Takes elements from BUILD_VDEFS and turns them into vdef operands of
779 STMT. */
780
781static inline void
782finalize_ssa_vdefs (gimple stmt)
783{
784 unsigned new_i;
785 struct voptype_d new_list;
786 voptype_p old_ops, ptr, last;
787
788 /* Set the symbols referenced by STMT. */
789 gimple_set_stored_syms (stmt, build_stores, &operands_bitmap_obstack);
790
791 /* If aliases have not been computed, do not instantiate a virtual
792 operator on STMT. Initially, we only compute the SSA form on
793 GIMPLE registers. The virtual SSA form is only computed after
794 alias analysis, so virtual operators will remain unrenamed and
795 the verifier will complain. However, alias analysis needs to
796 access symbol load/store information, so we need to compute
797 those. */
798 if (!gimple_aliases_computed_p (cfun))
799 return;
800
801 new_list.next = NULL;
802 last = &new_list;
803
804 old_ops = gimple_vdef_ops (stmt);
805 new_i = 0;
806 while (old_ops && new_i < VEC_length (tree, build_vdefs))
807 {
808 tree op = VEC_index (tree, build_vdefs, new_i);
809 unsigned new_uid = get_name_decl (op);
810 unsigned old_uid = get_name_decl (VDEF_RESULT (old_ops));
811
812 /* FIXME, for now each VDEF operator should have at most one
813 operand in their RHS. */
814 gcc_assert (VDEF_NUM (old_ops) == 1);
815
816 if (old_uid == new_uid)
817 {
818 /* If the symbols are the same, reuse the existing operand. */
819 last->next = old_ops;
820 last = old_ops;
821 old_ops = old_ops->next;
822 last->next = NULL;
823 set_virtual_use_link (VDEF_OP_PTR (last, 0), stmt);
824 new_i++;
825 }
826 else if (old_uid < new_uid)
827 {
828 /* If old is less than new, old goes to the free list. */
829 voptype_p next;
830 delink_imm_use (VDEF_OP_PTR (old_ops, 0));
831 next = old_ops->next;
832 add_vop_to_freelist (old_ops);
833 old_ops = next;
834 }
835 else
836 {
837 /* This is a new operand. */
838 last = add_vdef_op (stmt, op, 1, last);
839 new_i++;
840 }
841 }
842
843 /* If there is anything remaining in BUILD_VDEFS, simply emit it. */
844 for ( ; new_i < VEC_length (tree, build_vdefs); new_i++)
845 last = add_vdef_op (stmt, VEC_index (tree, build_vdefs, new_i), 1, last);
846
847 /* If there is anything in the old list, free it. */
848 if (old_ops)
849 {
850 for (ptr = old_ops; ptr; ptr = last)
851 {
852 last = ptr->next;
853 delink_imm_use (VDEF_OP_PTR (ptr, 0));
854 add_vop_to_freelist (ptr);
855 }
856 }
857
858 /* Now set STMT's operands. */
859 gimple_set_vdef_ops (stmt, new_list.next);
860
861#ifdef ENABLE_CHECKING
862 {
863 unsigned x = 0;
864 for (ptr = gimple_vdef_ops (stmt); ptr; ptr = ptr->next)
865 x++;
866
867 gcc_assert (x == VEC_length (tree, build_vdefs));
868 }
869#endif
870}
871
872
873/* Takes elements from BUILD_VUSES and turns them into VUSE operands of
874 STMT. */
875
876static inline void
877finalize_ssa_vuse_ops (gimple stmt)
878{
879 unsigned new_i, old_i;
880 voptype_p old_ops, last;
881 VEC(tree,heap) *new_ops;
882
883 /* Set the symbols referenced by STMT. */
884 gimple_set_loaded_syms (stmt, build_loads, &operands_bitmap_obstack);
885
886 /* If aliases have not been computed, do not instantiate a virtual
887 operator on STMT. Initially, we only compute the SSA form on
888 GIMPLE registers. The virtual SSA form is only computed after
889 alias analysis, so virtual operators will remain unrenamed and
890 the verifier will complain. However, alias analysis needs to
891 access symbol load/store information, so we need to compute
892 those. */
893 if (!gimple_aliases_computed_p (cfun))
894 return;
895
896 /* STMT should have at most one VUSE operator. */
897 old_ops = gimple_vuse_ops (stmt);
898 gcc_assert (old_ops == NULL || old_ops->next == NULL);
899
900 new_ops = NULL;
901 new_i = old_i = 0;
902 while (old_ops
903 && old_i < VUSE_NUM (old_ops)
904 && new_i < VEC_length (tree, build_vuses))
905 {
906 tree new_op = VEC_index (tree, build_vuses, new_i);
907 tree old_op = VUSE_OP (old_ops, old_i);
908 unsigned new_uid = get_name_decl (new_op);
909 unsigned old_uid = get_name_decl (old_op);
910
911 if (old_uid == new_uid)
912 {
913 /* If the symbols are the same, reuse the existing operand. */
914 VEC_safe_push (tree, heap, new_ops, old_op);
915 new_i++;
916 old_i++;
917 }
918 else if (old_uid < new_uid)
919 {
920 /* If OLD_UID is less than NEW_UID, the old operand has
921 disappeared, skip to the next old operand. */
922 old_i++;
923 }
924 else
925 {
926 /* This is a new operand. */
927 VEC_safe_push (tree, heap, new_ops, new_op);
928 new_i++;
929 }
930 }
931
932 /* If there is anything remaining in the build_vuses list, simply emit it. */
933 for ( ; new_i < VEC_length (tree, build_vuses); new_i++)
934 VEC_safe_push (tree, heap, new_ops, VEC_index (tree, build_vuses, new_i));
935
936 /* If there is anything in the old list, free it. */
937 if (old_ops)
938 {
939 for (old_i = 0; old_i < VUSE_NUM (old_ops); old_i++)
940 delink_imm_use (VUSE_OP_PTR (old_ops, old_i));
941 add_vop_to_freelist (old_ops);
942 gimple_set_vuse_ops (stmt, NULL);
943 }
944
945 /* If there are any operands, instantiate a VUSE operator for STMT. */
946 if (new_ops)
947 {
948 tree op;
949 unsigned i;
950
951 last = add_vuse_op (stmt, NULL, VEC_length (tree, new_ops), NULL);
952
953 for (i = 0; VEC_iterate (tree, new_ops, i, op); i++)
954 SET_USE (VUSE_OP_PTR (last, (int) i), op);
955
956 gimple_set_vuse_ops (stmt, last);
957 VEC_free (tree, heap, new_ops);
958 }
959
960#ifdef ENABLE_CHECKING
961 {
962 unsigned x;
963
964 if (gimple_vuse_ops (stmt))
965 {
966 gcc_assert (gimple_vuse_ops (stmt)->next == NULL);
967 x = VUSE_NUM (gimple_vuse_ops (stmt));
968 }
969 else
970 x = 0;
971
972 gcc_assert (x == VEC_length (tree, build_vuses));
973 }
974#endif
975}
976
977/* Return a new VUSE operand vector for STMT. */
978
979static void
980finalize_ssa_vuses (gimple stmt)
981{
982 unsigned num, num_vdefs;
983 unsigned vuse_index;
984
985 /* Remove superfluous VUSE operands. If the statement already has a
986 VDEF operator for a variable 'a', then a VUSE for 'a' is not
987 needed because VDEFs imply a VUSE of the variable. For instance,
988 suppose that variable 'a' is pointed-to by p and q:
989
990 # VUSE <a_2>
991 # a_3 = VDEF <a_2>
992 *p = *q;
993
994 The VUSE <a_2> is superfluous because it is implied by the
995 VDEF operator. */
996 num = VEC_length (tree, build_vuses);
997 num_vdefs = VEC_length (tree, build_vdefs);
998
999 if (num > 0 && num_vdefs > 0)
1000 for (vuse_index = 0; vuse_index < VEC_length (tree, build_vuses); )
1001 {
1002 tree vuse;
1003 vuse = VEC_index (tree, build_vuses, vuse_index);
1004 if (TREE_CODE (vuse) != SSA_NAME)
1005 {
1006 var_ann_t ann = var_ann (vuse);
1007 ann->in_vuse_list = 0;
1008 if (ann->in_vdef_list)
1009 {
1010 VEC_ordered_remove (tree, build_vuses, vuse_index);
1011 continue;
1012 }
1013 }
1014 vuse_index++;
1015 }
1016
1017 finalize_ssa_vuse_ops (stmt);
1018}
1019
1020
1021/* Clear the in_list bits and empty the build array for VDEFs and
1022 VUSEs. */
1023
1024static inline void
1025cleanup_build_arrays (void)
1026{
1027 unsigned i;
1028 tree t;
1029
1030 for (i = 0; VEC_iterate (tree, build_vdefs, i, t); i++)
1031 if (TREE_CODE (t) != SSA_NAME)
1032 var_ann (t)->in_vdef_list = false;
1033
1034 for (i = 0; VEC_iterate (tree, build_vuses, i, t); i++)
1035 if (TREE_CODE (t) != SSA_NAME)
1036 var_ann (t)->in_vuse_list = false;
1037
1038 VEC_truncate (tree, build_vdefs, 0);
1039 VEC_truncate (tree, build_vuses, 0);
1040 VEC_truncate (tree, build_defs, 0);
1041 VEC_truncate (tree, build_uses, 0);
1042 bitmap_clear (build_loads);
1043 bitmap_clear (build_stores);
1044}
1045
1046
1047/* Finalize all the build vectors, fill the new ones into INFO. */
1048
1049static inline void
1050finalize_ssa_stmt_operands (gimple stmt)
1051{
1052 finalize_ssa_defs (stmt);
1053 finalize_ssa_uses (stmt);
1054 if (gimple_has_mem_ops (stmt))
1055 {
1056 finalize_ssa_vdefs (stmt);
1057 finalize_ssa_vuses (stmt);
1058 }
1059 cleanup_build_arrays ();
1060}
1061
1062
1063/* Start the process of building up operands vectors in INFO. */
1064
1065static inline void
1066start_ssa_stmt_operands (void)
1067{
1068 gcc_assert (VEC_length (tree, build_defs) == 0);
1069 gcc_assert (VEC_length (tree, build_uses) == 0);
1070 gcc_assert (VEC_length (tree, build_vuses) == 0);
1071 gcc_assert (VEC_length (tree, build_vdefs) == 0);
1072 gcc_assert (bitmap_empty_p (build_loads));
1073 gcc_assert (bitmap_empty_p (build_stores));
1074}
1075
1076
1077/* Add DEF_P to the list of pointers to operands. */
1078
1079static inline void
1080append_def (tree *def_p)
1081{
1082 VEC_safe_push (tree, heap, build_defs, (tree) def_p);
1083}
1084
1085
1086/* Add USE_P to the list of pointers to operands. */
1087
1088static inline void
1089append_use (tree *use_p)
1090{
1091 VEC_safe_push (tree, heap, build_uses, (tree) use_p);
1092}
1093
1094
1095/* Add VAR to the set of variables that require a VDEF operator. */
1096
1097static inline void
1098append_vdef (tree var)
1099{
1100 tree sym;
1101
1102 if (TREE_CODE (var) != SSA_NAME)
1103 {
1104 tree mpt;
1105 var_ann_t ann;
1106
1107 /* If VAR belongs to a memory partition, use it instead of VAR. */
1108 mpt = memory_partition (var);
1109 if (mpt)
1110 var = mpt;
1111
1112 /* Don't allow duplicate entries. */
1113 ann = get_var_ann (var);
1114 if (ann->in_vdef_list)
1115 return;
1116
1117 ann->in_vdef_list = true;
1118 sym = var;
1119 }
1120 else
1121 sym = SSA_NAME_VAR (var);
1122
1123 VEC_safe_push (tree, heap, build_vdefs, var);
1124 bitmap_set_bit (build_stores, DECL_UID (sym));
1125}
1126
1127
1128/* Add VAR to the set of variables that require a VUSE operator. */
1129
1130static inline void
1131append_vuse (tree var)
1132{
1133 tree sym;
1134
1135 if (TREE_CODE (var) != SSA_NAME)
1136 {
1137 tree mpt;
1138 var_ann_t ann;
1139
1140 /* If VAR belongs to a memory partition, use it instead of VAR. */
1141 mpt = memory_partition (var);
1142 if (mpt)
1143 var = mpt;
1144
1145 /* Don't allow duplicate entries. */
1146 ann = get_var_ann (var);
1147 if (ann->in_vuse_list)
1148 return;
1149 else if (ann->in_vdef_list)
1150 {
1151 /* We don't want a vuse if we already have a vdef, but we must
1152 still put this in build_loads. */
1153 bitmap_set_bit (build_loads, DECL_UID (var));
1154 return;
1155 }
1156
1157 ann->in_vuse_list = true;
1158 sym = var;
1159 }
1160 else
1161 sym = SSA_NAME_VAR (var);
1162
1163 VEC_safe_push (tree, heap, build_vuses, var);
1164 bitmap_set_bit (build_loads, DECL_UID (sym));
1165}
1166
1167
1168/* REF is a tree that contains the entire pointer dereference
1169 expression, if available, or NULL otherwise. ALIAS is the variable
1170 we are asking if REF can access. OFFSET and SIZE come from the
1171 memory access expression that generated this virtual operand.
1172
1173 XXX: We should handle the NO_ALIAS attributes here. */
1174
1175static bool
1176access_can_touch_variable (tree ref, tree alias, HOST_WIDE_INT offset,
1177 HOST_WIDE_INT size)
1178{
1179 bool offsetgtz = offset > 0;
1180 unsigned HOST_WIDE_INT uoffset = (unsigned HOST_WIDE_INT) offset;
1181 tree base = ref ? get_base_address (ref) : NULL;
1182
1183 /* If ALIAS is .GLOBAL_VAR then the memory reference REF must be
1184 using a call-clobbered memory tag. By definition, call-clobbered
1185 memory tags can always touch .GLOBAL_VAR. */
1186 if (alias == gimple_global_var (cfun))
1187 return true;
1188
1189 /* If ref is a TARGET_MEM_REF, just return true, as we can't really
1190 disambiguate them right now. */
1191 if (ref && TREE_CODE (ref) == TARGET_MEM_REF)
1192 return true;
1193
1194 /* Without strict aliasing, it is impossible for a component access
1195 through a pointer to touch a random variable, unless that
1196 variable *is* a structure or a pointer.
1197
1198 That is, given p->c, and some random global variable b,
1199 there is no legal way that p->c could be an access to b.
1200
1201 Without strict aliasing on, we consider it legal to do something
1202 like:
1203
1204 struct foos { int l; };
1205 int foo;
1206 static struct foos *getfoo(void);
1207 int main (void)
1208 {
1209 struct foos *f = getfoo();
1210 f->l = 1;
1211 foo = 2;
1212 if (f->l == 1)
1213 abort();
1214 exit(0);
1215 }
1216 static struct foos *getfoo(void)
1217 { return (struct foos *)&foo; }
1218
1219 (taken from 20000623-1.c)
1220
1221 The docs also say/imply that access through union pointers
1222 is legal (but *not* if you take the address of the union member,
1223 i.e. the inverse), such that you can do
1224
1225 typedef union {
1226 int d;
1227 } U;
1228
1229 int rv;
1230 void breakme()
1231 {
1232 U *rv0;
1233 U *pretmp = (U*)&rv;
1234 rv0 = pretmp;
1235 rv0->d = 42;
1236 }
1237 To implement this, we just punt on accesses through union
1238 pointers entirely.
1239
1240 Another case we have to allow is accessing a variable
1241 through an array access at offset zero. This happens from
1242 code generated by the fortran frontend like
1243
1244 char[1:1] & my_char_ref;
1245 char my_char;
1246 my_char_ref_1 = (char[1:1] &) &my_char;
1247 D.874_2 = (*my_char_ref_1)[1]{lb: 1 sz: 1};
1248 */
1249 if (ref
1250 && flag_strict_aliasing
1251 && TREE_CODE (ref) != INDIRECT_REF
1252 && !MTAG_P (alias)
1253 && base
1254 && (TREE_CODE (base) != INDIRECT_REF
1255 || TREE_CODE (TREE_TYPE (base)) != UNION_TYPE)
1256 && (TREE_CODE (base) != INDIRECT_REF
1257 || TREE_CODE (ref) != ARRAY_REF
1258 || offset != 0
1259 || (DECL_SIZE (alias)
1260 && TREE_CODE (DECL_SIZE (alias)) == INTEGER_CST
1261 && size != -1
1262 && (unsigned HOST_WIDE_INT)size
1263 != TREE_INT_CST_LOW (DECL_SIZE (alias))))
1264 && !AGGREGATE_TYPE_P (TREE_TYPE (alias))
1265 && TREE_CODE (TREE_TYPE (alias)) != COMPLEX_TYPE
1266 && !var_ann (alias)->is_heapvar
1267 /* When the struct has may_alias attached to it, we need not to
1268 return true. */
1269 && get_alias_set (base))
1270 {
1271#ifdef ACCESS_DEBUGGING
1272 fprintf (stderr, "Access to ");
1273 print_generic_expr (stderr, ref, 0);
1274 fprintf (stderr, " may not touch ");
1275 print_generic_expr (stderr, alias, 0);
1276 fprintf (stderr, " in function %s\n", get_name (current_function_decl));
1277#endif
1278 return false;
1279 }
1280
1281 /* If the offset of the access is greater than the size of one of
1282 the possible aliases, it can't be touching that alias, because it
1283 would be past the end of the structure. */
1284 else if (ref
1285 && flag_strict_aliasing
1286 && TREE_CODE (ref) != INDIRECT_REF
1287 && !MTAG_P (alias)
1288 && !var_ann (alias)->is_heapvar
1289 && !POINTER_TYPE_P (TREE_TYPE (alias))
1290 && offsetgtz
1291 && DECL_SIZE (alias)
1292 && TREE_CODE (DECL_SIZE (alias)) == INTEGER_CST
1293 && uoffset >= TREE_INT_CST_LOW (DECL_SIZE (alias)))
1294 {
1295#ifdef ACCESS_DEBUGGING
1296 fprintf (stderr, "Access to ");
1297 print_generic_expr (stderr, ref, 0);
1298 fprintf (stderr, " may not touch ");
1299 print_generic_expr (stderr, alias, 0);
1300 fprintf (stderr, " in function %s\n", get_name (current_function_decl));
1301#endif
1302 return false;
1303 }
1304
1305 return true;
1306}
1307
1308/* Add VAR to the virtual operands for STMT. FLAGS is as in
1309 get_expr_operands. FULL_REF is a tree that contains the entire
1310 pointer dereference expression, if available, or NULL otherwise.
1311 OFFSET and SIZE come from the memory access expression that
1312 generated this virtual operand. IS_CALL_SITE is true if the
1313 affected statement is a call site. */
1314
1315static void
1316add_virtual_operand (tree var, gimple stmt, int flags,
1317 tree full_ref, HOST_WIDE_INT offset,
1318 HOST_WIDE_INT size, bool is_call_site)
1319{
1320 bitmap aliases = NULL;
1321 tree sym;
1322 var_ann_t v_ann;
1323
1324 sym = (TREE_CODE (var) == SSA_NAME ? SSA_NAME_VAR (var) : var);
1325 v_ann = var_ann (sym);
1326
1327 /* Mark the statement as having memory operands. */
1328 gimple_set_references_memory (stmt, true);
1329
1330 /* If the variable cannot be modified and this is a VDEF change
1331 it into a VUSE. This happens when read-only variables are marked
1332 call-clobbered and/or aliased to writable variables. So we only
1333 check that this only happens on non-specific stores.
1334
1335 Note that if this is a specific store, i.e. associated with a
1336 MODIFY_EXPR, then we can't suppress the VDEF, lest we run
1337 into validation problems.
1338
1339 This can happen when programs cast away const, leaving us with a
1340 store to read-only memory. If the statement is actually executed
1341 at runtime, then the program is ill formed. If the statement is
1342 not executed then all is well. At the very least, we cannot ICE. */
1343 if ((flags & opf_implicit) && unmodifiable_var_p (var))
1344 flags &= ~opf_def;
1345
1346 /* The variable is not a GIMPLE register. Add it (or its aliases) to
1347 virtual operands, unless the caller has specifically requested
1348 not to add virtual operands (used when adding operands inside an
1349 ADDR_EXPR expression). */
1350 if (flags & opf_no_vops)
1351 return;
1352
1353 if (MTAG_P (var))
1354 aliases = MTAG_ALIASES (var);
1355
1356 if (aliases == NULL)
1357 {
1358 if (!gimple_aliases_computed_p (cfun) && (flags & opf_def))
1359 gimple_set_has_volatile_ops (stmt, true);
1360
1361 /* The variable is not aliased or it is an alias tag. */
1362 if (flags & opf_def)
1363 append_vdef (var);
1364 else
1365 append_vuse (var);
1366 }
1367 else
1368 {
1369 bitmap_iterator bi;
1370 unsigned int i;
1371 bool none_added = true;
1372
1373 /* The variable is aliased. Add its aliases to the virtual
1374 operands. */
1375 gcc_assert (!bitmap_empty_p (aliases));
1376
1377 EXECUTE_IF_SET_IN_BITMAP (aliases, 0, i, bi)
1378 {
1379 tree al = referenced_var (i);
1380
1381 /* Call-clobbered tags may have non-call-clobbered
1382 symbols in their alias sets. Ignore them if we are
1383 adding VOPs for a call site. */
1384 if (is_call_site && !is_call_clobbered (al))
1385 continue;
1386
1387 /* If we do not know the full reference tree or if the access is
1388 unspecified [0, -1], we cannot prune it. Otherwise try doing
1389 so using access_can_touch_variable. */
1390 if (full_ref
1391 && !access_can_touch_variable (full_ref, al, offset, size))
1392 continue;
1393
1394 if (flags & opf_def)
1395 append_vdef (al);
1396 else
1397 append_vuse (al);
1398 none_added = false;
1399 }
1400
1401 if (flags & opf_def)
1402 {
1403 /* If the variable is also an alias tag, add a virtual
1404 operand for it, otherwise we will miss representing
1405 references to the members of the variable's alias set.
1406 This fixes the bug in gcc.c-torture/execute/20020503-1.c.
1407
1408 It is also necessary to add bare defs on clobbers for
1409 SMT's, so that bare SMT uses caused by pruning all the
1410 aliases will link up properly with calls. In order to
1411 keep the number of these bare defs we add down to the
1412 minimum necessary, we keep track of which SMT's were used
1413 alone in statement vdefs or VUSEs. */
1414 if (none_added
1415 || (TREE_CODE (var) == SYMBOL_MEMORY_TAG
1416 && is_call_site))
1417 append_vdef (var);
1418 }
1419 else
1420 {
1421 /* Even if no aliases have been added, we still need to
1422 establish def-use and use-def chains, lest
1423 transformations think that this is not a memory
1424 reference. For an example of this scenario, see
1425 testsuite/g++.dg/opt/cleanup1.C. */
1426 if (none_added)
1427 append_vuse (var);
1428 }
1429 }
1430}
1431
1432
1433/* Add *VAR_P to the appropriate operand array for statement STMT.
1434 FLAGS is as in get_expr_operands. If *VAR_P is a GIMPLE register,
1435 it will be added to the statement's real operands, otherwise it is
1436 added to virtual operands. */
1437
1438static void
1439add_stmt_operand (tree *var_p, gimple stmt, int flags)
1440{
1441 tree var, sym;
1442 var_ann_t v_ann;
1443
1444 gcc_assert (SSA_VAR_P (*var_p));
1445
1446 var = *var_p;
1447 sym = (TREE_CODE (var) == SSA_NAME ? SSA_NAME_VAR (var) : var);
1448 v_ann = var_ann (sym);
1449
1450 /* Mark statements with volatile operands. */
1451 if (TREE_THIS_VOLATILE (sym))
1452 gimple_set_has_volatile_ops (stmt, true);
1453
1454 if (is_gimple_reg (sym))
1455 {
1456 /* The variable is a GIMPLE register. Add it to real operands. */
1457 if (flags & opf_def)
1458 append_def (var_p);
1459 else
1460 append_use (var_p);
1461 }
1462 else
1463 add_virtual_operand (var, stmt, flags, NULL_TREE, 0, -1, false);
1464}
1465
1466/* Subroutine of get_indirect_ref_operands. ADDR is the address
1467 that is dereferenced, the meaning of the rest of the arguments
1468 is the same as in get_indirect_ref_operands. */
1469
1470static void
1471get_addr_dereference_operands (gimple stmt, tree *addr, int flags,
1472 tree full_ref, HOST_WIDE_INT offset,
1473 HOST_WIDE_INT size, bool recurse_on_base)
1474{
1475 tree ptr = *addr;
1476
1477 /* Mark the statement as having memory operands. */
1478 gimple_set_references_memory (stmt, true);
1479
1480 if (SSA_VAR_P (ptr))
1481 {
1482 struct ptr_info_def *pi = NULL;
1483
1484 /* If PTR has flow-sensitive points-to information, use it. */
1485 if (TREE_CODE (ptr) == SSA_NAME
1486 && (pi = SSA_NAME_PTR_INFO (ptr)) != NULL
1487 && pi->name_mem_tag)
1488 {
1489 /* PTR has its own memory tag. Use it. */
1490 add_virtual_operand (pi->name_mem_tag, stmt, flags,
1491 full_ref, offset, size, false);
1492 }
1493 else
1494 {
1495 /* If PTR is not an SSA_NAME or it doesn't have a name
1496 tag, use its symbol memory tag. */
1497 var_ann_t v_ann;
1498
1499 /* If we are emitting debugging dumps, display a warning if
1500 PTR is an SSA_NAME with no flow-sensitive alias
1501 information. That means that we may need to compute
1502 aliasing again or that a propagation pass forgot to
1503 update the alias information on the pointers. */
1504 if (dump_file
1505 && TREE_CODE (ptr) == SSA_NAME
1506 && (pi == NULL
1507 || (pi->name_mem_tag == NULL_TREE
1508 && !pi->pt_anything))
1509 && gimple_aliases_computed_p (cfun))
1510 {
1511 fprintf (dump_file,
1512 "NOTE: no flow-sensitive alias info for ");
1513 print_generic_expr (dump_file, ptr, dump_flags);
1514 fprintf (dump_file, " in ");
1515 print_gimple_stmt (dump_file, stmt, 0, 0);
1516 }
1517
1518 if (TREE_CODE (ptr) == SSA_NAME)
1519 ptr = SSA_NAME_VAR (ptr);
1520 v_ann = var_ann (ptr);
1521
1522 /* If we don't know what this pointer points to then we have
1523 to make sure to not prune virtual operands based on offset
1524 and size. */
1525 if (v_ann->symbol_mem_tag)
1526 {
1527 add_virtual_operand (v_ann->symbol_mem_tag, stmt, flags,
1528 full_ref, 0, -1, false);
1529 /* Make sure we add the SMT itself. */
1530 if (!(flags & opf_no_vops))
1531 {
1532 if (flags & opf_def)
1533 append_vdef (v_ann->symbol_mem_tag);
1534 else
1535 append_vuse (v_ann->symbol_mem_tag);
1536 }
1537 }
1538
1539 /* Aliasing information is missing; mark statement as
1540 volatile so we won't optimize it out too actively. */
1541 else if (!gimple_aliases_computed_p (cfun)
1542 && (flags & opf_def))
1543 gimple_set_has_volatile_ops (stmt, true);
1544 }
1545 }
1546 else if (TREE_CODE (ptr) == INTEGER_CST)
1547 {
1548 /* If a constant is used as a pointer, we can't generate a real
1549 operand for it but we mark the statement volatile to prevent
1550 optimizations from messing things up. */
1551 gimple_set_has_volatile_ops (stmt, true);
1552 return;
1553 }
1554 else
1555 {
1556 /* Ok, this isn't even is_gimple_min_invariant. Something's broke. */
1557 gcc_unreachable ();
1558 }
1559
1560 /* If requested, add a USE operand for the base pointer. */
1561 if (recurse_on_base)
1562 get_expr_operands (stmt, addr, opf_use);
1563}
1564
1565
1566/* A subroutine of get_expr_operands to handle INDIRECT_REF,
1567 ALIGN_INDIRECT_REF and MISALIGNED_INDIRECT_REF.
1568
1569 STMT is the statement being processed, EXPR is the INDIRECT_REF
1570 that got us here.
1571
1572 FLAGS is as in get_expr_operands.
1573
1574 FULL_REF contains the full pointer dereference expression, if we
1575 have it, or NULL otherwise.
1576
1577 OFFSET and SIZE are the location of the access inside the
1578 dereferenced pointer, if known.
1579
1580 RECURSE_ON_BASE should be set to true if we want to continue
1581 calling get_expr_operands on the base pointer, and false if
1582 something else will do it for us. */
1583
1584static void
1585get_indirect_ref_operands (gimple stmt, tree expr, int flags, tree full_ref,
1586 HOST_WIDE_INT offset, HOST_WIDE_INT size,
1587 bool recurse_on_base)
1588{
1589 tree *pptr = &TREE_OPERAND (expr, 0);
1590
1591 if (TREE_THIS_VOLATILE (expr))
1592 gimple_set_has_volatile_ops (stmt, true);
1593
1594 get_addr_dereference_operands (stmt, pptr, flags, full_ref, offset, size,
1595 recurse_on_base);
1596}
1597
1598
1599/* A subroutine of get_expr_operands to handle TARGET_MEM_REF. */
1600
1601static void
1602get_tmr_operands (gimple stmt, tree expr, int flags)
1603{
1604 tree tag;
1605
1606 /* Mark the statement as having memory operands. */
1607 gimple_set_references_memory (stmt, true);
1608
4b1e227d
SW
1609 if (TREE_THIS_VOLATILE (expr))
1610 gimple_set_has_volatile_ops (stmt, true);
1611
c251ad9e
SS
1612 /* First record the real operands. */
1613 get_expr_operands (stmt, &TMR_BASE (expr), opf_use);
1614 get_expr_operands (stmt, &TMR_INDEX (expr), opf_use);
1615
1616 if (TMR_SYMBOL (expr))
1617 gimple_add_to_addresses_taken (stmt, TMR_SYMBOL (expr));
1618
1619 tag = TMR_TAG (expr);
1620 if (!tag)
1621 {
1622 /* Something weird, so ensure that we will be careful. */
1623 gimple_set_has_volatile_ops (stmt, true);
1624 return;
1625 }
1626 if (!MTAG_P (tag))
1627 {
1628 get_expr_operands (stmt, &tag, flags);
1629 return;
1630 }
1631
1632 add_virtual_operand (tag, stmt, flags, expr, 0, -1, false);
1633}
1634
1635
1636/* Add clobbering definitions for .GLOBAL_VAR or for each of the call
1637 clobbered variables in the function. */
1638
1639static void
1640add_call_clobber_ops (gimple stmt, tree callee ATTRIBUTE_UNUSED)
1641{
1642 unsigned u;
1643 bitmap_iterator bi;
1644 bitmap not_read_b, not_written_b;
1645
1646 gcc_assert (!(gimple_call_flags (stmt) & (ECF_PURE | ECF_CONST)));
1647
1648 /* If we created .GLOBAL_VAR earlier, just use it. */
1649 if (gimple_global_var (cfun))
1650 {
1651 tree var = gimple_global_var (cfun);
1652 add_virtual_operand (var, stmt, opf_def, NULL, 0, -1, true);
1653 return;
1654 }
1655
1656 /* Get info for local and module level statics. There is a bit
1657 set for each static if the call being processed does not read
1658 or write that variable. */
1659 not_read_b = callee ? ipa_reference_get_not_read_global (cgraph_node (callee)) : NULL;
1660 not_written_b = callee ? ipa_reference_get_not_written_global (cgraph_node (callee)) : NULL;
1661
1662 /* Add a VDEF operand for every call clobbered variable. */
1663 EXECUTE_IF_SET_IN_BITMAP (gimple_call_clobbered_vars (cfun), 0, u, bi)
1664 {
1665 tree var = referenced_var_lookup (u);
1666 tree real_var = var;
1667 bool not_read;
1668 bool not_written;
1669
1670 not_read = not_read_b
1671 ? bitmap_bit_p (not_read_b, DECL_UID (real_var))
1672 : false;
1673
1674 not_written = not_written_b
1675 ? bitmap_bit_p (not_written_b, DECL_UID (real_var))
1676 : false;
1677 gcc_assert (!unmodifiable_var_p (var));
1678
1679 clobber_stats.clobbered_vars++;
1680
1681 /* See if this variable is really clobbered by this function. */
1682
1683 if (not_written)
1684 {
1685 clobber_stats.static_write_clobbers_avoided++;
1686 if (!not_read)
1687 add_virtual_operand (var, stmt, opf_use, NULL, 0, -1, true);
1688 else
1689 clobber_stats.static_read_clobbers_avoided++;
1690 }
1691 else
1692 add_virtual_operand (var, stmt, opf_def, NULL, 0, -1, true);
1693 }
1694}
1695
1696
1697/* Add VUSE operands for .GLOBAL_VAR or all call clobbered variables in the
1698 function. */
1699
1700static void
1701add_call_read_ops (gimple stmt, tree callee ATTRIBUTE_UNUSED)
1702{
1703 unsigned u;
1704 bitmap_iterator bi;
1705 bitmap not_read_b;
1706
1707 /* Const functions do not reference memory. */
1708 if (gimple_call_flags (stmt) & ECF_CONST)
1709 return;
1710
1711 not_read_b = callee ? ipa_reference_get_not_read_global (cgraph_node (callee)) : NULL;
1712
1713 /* For pure functions we compute non-escaped uses separately. */
1714 if (gimple_call_flags (stmt) & ECF_PURE)
1715 EXECUTE_IF_SET_IN_BITMAP (gimple_call_used_vars (cfun), 0, u, bi)
1716 {
1717 tree var = referenced_var_lookup (u);
1718 tree real_var = var;
1719 bool not_read;
1720
1721 if (unmodifiable_var_p (var))
1722 continue;
1723
1724 not_read = not_read_b
1725 ? bitmap_bit_p (not_read_b, DECL_UID (real_var))
1726 : false;
1727
1728 clobber_stats.readonly_clobbers++;
1729
1730 /* See if this variable is really used by this function. */
1731 if (!not_read)
1732 add_virtual_operand (var, stmt, opf_use, NULL, 0, -1, true);
1733 else
1734 clobber_stats.static_readonly_clobbers_avoided++;
1735 }
1736
1737 /* Add a VUSE for .GLOBAL_VAR if it has been created. See
1738 add_referenced_var for the heuristic used to decide whether to
1739 create .GLOBAL_VAR. */
1740 if (gimple_global_var (cfun))
1741 {
1742 tree var = gimple_global_var (cfun);
1743 add_virtual_operand (var, stmt, opf_use, NULL, 0, -1, true);
1744 return;
1745 }
1746
1747 /* Add a VUSE for each call-clobbered variable. */
1748 EXECUTE_IF_SET_IN_BITMAP (gimple_call_clobbered_vars (cfun), 0, u, bi)
1749 {
1750 tree var = referenced_var (u);
1751 tree real_var = var;
1752 bool not_read;
1753
1754 clobber_stats.readonly_clobbers++;
1755
1756 not_read = not_read_b ? bitmap_bit_p (not_read_b, DECL_UID (real_var))
1757 : false;
1758
1759 if (not_read)
1760 {
1761 clobber_stats.static_readonly_clobbers_avoided++;
1762 continue;
1763 }
1764
1765 add_virtual_operand (var, stmt, opf_use, NULL, 0, -1, true);
1766 }
1767}
1768
1769
1770/* If STMT is a call that may clobber globals and other symbols that
1771 escape, add them to the VDEF/VUSE lists for it. */
1772
1773static void
1774maybe_add_call_clobbered_vops (gimple stmt)
1775{
1776 int call_flags = gimple_call_flags (stmt);
1777
1778 /* Mark the statement as having memory operands. */
1779 gimple_set_references_memory (stmt, true);
1780
1781 /* If aliases have been computed already, add VDEF or VUSE
1782 operands for all the symbols that have been found to be
1783 call-clobbered. */
1784 if (gimple_aliases_computed_p (cfun) && !(call_flags & ECF_NOVOPS))
1785 {
1786 /* A 'pure' or a 'const' function never call-clobbers anything.
1787 A 'noreturn' function might, but since we don't return anyway
1788 there is no point in recording that. */
1789 if (!(call_flags & (ECF_PURE | ECF_CONST | ECF_NORETURN)))
1790 add_call_clobber_ops (stmt, gimple_call_fndecl (stmt));
1791 else if (!(call_flags & ECF_CONST))
1792 add_call_read_ops (stmt, gimple_call_fndecl (stmt));
1793 }
1794}
1795
1796
1797/* Scan operands in the ASM_EXPR stmt referred to in INFO. */
1798
1799static void
1800get_asm_expr_operands (gimple stmt)
1801{
1802 size_t i, noutputs;
1803 const char **oconstraints;
1804 const char *constraint;
1805 bool allows_mem, allows_reg, is_inout;
1806
1807 noutputs = gimple_asm_noutputs (stmt);
1808 oconstraints = (const char **) alloca ((noutputs) * sizeof (const char *));
1809
1810 /* Gather all output operands. */
1811 for (i = 0; i < gimple_asm_noutputs (stmt); i++)
1812 {
1813 tree link = gimple_asm_output_op (stmt, i);
1814 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
1815 oconstraints[i] = constraint;
1816 parse_output_constraint (&constraint, i, 0, 0, &allows_mem,
1817 &allows_reg, &is_inout);
1818
1819 /* This should have been split in gimplify_asm_expr. */
1820 gcc_assert (!allows_reg || !is_inout);
1821
1822 /* Memory operands are addressable. Note that STMT needs the
1823 address of this operand. */
1824 if (!allows_reg && allows_mem)
1825 {
1826 tree t = get_base_address (TREE_VALUE (link));
1827 if (t && DECL_P (t))
1828 gimple_add_to_addresses_taken (stmt, t);
1829 }
1830
1831 get_expr_operands (stmt, &TREE_VALUE (link), opf_def);
1832 }
1833
1834 /* Gather all input operands. */
1835 for (i = 0; i < gimple_asm_ninputs (stmt); i++)
1836 {
1837 tree link = gimple_asm_input_op (stmt, i);
1838 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
1839 parse_input_constraint (&constraint, 0, 0, noutputs, 0, oconstraints,
1840 &allows_mem, &allows_reg);
1841
1842 /* Memory operands are addressable. Note that STMT needs the
1843 address of this operand. */
1844 if (!allows_reg && allows_mem)
1845 {
1846 tree t = get_base_address (TREE_VALUE (link));
1847 if (t && DECL_P (t))
1848 gimple_add_to_addresses_taken (stmt, t);
1849 }
1850
1851 get_expr_operands (stmt, &TREE_VALUE (link), 0);
1852 }
1853
1854 /* Clobber all memory and addressable symbols for asm ("" : : : "memory"); */
1855 for (i = 0; i < gimple_asm_nclobbers (stmt); i++)
1856 {
1857 tree link = gimple_asm_clobber_op (stmt, i);
1858 if (strcmp (TREE_STRING_POINTER (TREE_VALUE (link)), "memory") == 0)
1859 {
1860 unsigned i;
1861 bitmap_iterator bi;
1862
1863 /* Mark the statement as having memory operands. */
1864 gimple_set_references_memory (stmt, true);
1865
1866 EXECUTE_IF_SET_IN_BITMAP (gimple_call_clobbered_vars (cfun), 0, i, bi)
1867 {
1868 tree var = referenced_var (i);
1869 add_stmt_operand (&var, stmt, opf_def | opf_implicit);
1870 }
1871
1872 EXECUTE_IF_SET_IN_BITMAP (gimple_addressable_vars (cfun), 0, i, bi)
1873 {
1874 tree var = referenced_var (i);
1875 add_stmt_operand (&var, stmt, opf_def | opf_implicit);
1876 }
1877 break;
1878 }
1879 }
1880}
1881
1882
1883/* Recursively scan the expression pointed to by EXPR_P in statement
1884 STMT. FLAGS is one of the OPF_* constants modifying how to
1885 interpret the operands found. */
1886
1887static void
1888get_expr_operands (gimple stmt, tree *expr_p, int flags)
1889{
1890 enum tree_code code;
1891 enum tree_code_class codeclass;
1892 tree expr = *expr_p;
1893
1894 if (expr == NULL)
1895 return;
1896
1897 code = TREE_CODE (expr);
1898 codeclass = TREE_CODE_CLASS (code);
1899
1900 switch (code)
1901 {
1902 case ADDR_EXPR:
1903 /* Taking the address of a variable does not represent a
1904 reference to it, but the fact that the statement takes its
1905 address will be of interest to some passes (e.g. alias
1906 resolution). */
1907 gimple_add_to_addresses_taken (stmt, TREE_OPERAND (expr, 0));
1908
1909 /* If the address is invariant, there may be no interesting
1910 variable references inside. */
1911 if (is_gimple_min_invariant (expr))
1912 return;
1913
1914 /* Otherwise, there may be variables referenced inside but there
1915 should be no VUSEs created, since the referenced objects are
1916 not really accessed. The only operands that we should find
1917 here are ARRAY_REF indices which will always be real operands
1918 (GIMPLE does not allow non-registers as array indices). */
1919 flags |= opf_no_vops;
1920 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
1921 return;
1922
1923 case SSA_NAME:
1924 case SYMBOL_MEMORY_TAG:
1925 case NAME_MEMORY_TAG:
1926 add_stmt_operand (expr_p, stmt, flags);
1927 return;
1928
1929 case VAR_DECL:
1930 case PARM_DECL:
1931 case RESULT_DECL:
1932 add_stmt_operand (expr_p, stmt, flags);
1933 return;
1934
1935 case MISALIGNED_INDIRECT_REF:
1936 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), flags);
1937 /* fall through */
1938
1939 case ALIGN_INDIRECT_REF:
1940 case INDIRECT_REF:
1941 get_indirect_ref_operands (stmt, expr, flags, expr, 0, -1, true);
1942 return;
1943
1944 case TARGET_MEM_REF:
1945 get_tmr_operands (stmt, expr, flags);
1946 return;
1947
1948 case ARRAY_REF:
1949 case ARRAY_RANGE_REF:
1950 case COMPONENT_REF:
1951 case REALPART_EXPR:
1952 case IMAGPART_EXPR:
1953 {
1954 tree ref;
1955 HOST_WIDE_INT offset, size, maxsize;
1956
1957 if (TREE_THIS_VOLATILE (expr))
1958 gimple_set_has_volatile_ops (stmt, true);
1959
1960 ref = get_ref_base_and_extent (expr, &offset, &size, &maxsize);
1961 if (TREE_CODE (ref) == INDIRECT_REF)
1962 {
1963 get_indirect_ref_operands (stmt, ref, flags, expr, offset,
1964 maxsize, false);
1965 flags |= opf_no_vops;
1966 }
1967
1968 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
1969
1970 if (code == COMPONENT_REF)
1971 {
1972 if (TREE_THIS_VOLATILE (TREE_OPERAND (expr, 1)))
1973 gimple_set_has_volatile_ops (stmt, true);
1974 get_expr_operands (stmt, &TREE_OPERAND (expr, 2), opf_use);
1975 }
1976 else if (code == ARRAY_REF || code == ARRAY_RANGE_REF)
1977 {
1978 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), opf_use);
1979 get_expr_operands (stmt, &TREE_OPERAND (expr, 2), opf_use);
1980 get_expr_operands (stmt, &TREE_OPERAND (expr, 3), opf_use);
1981 }
1982
1983 return;
1984 }
1985
1986 case WITH_SIZE_EXPR:
1987 /* WITH_SIZE_EXPR is a pass-through reference to its first argument,
1988 and an rvalue reference to its second argument. */
1989 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), opf_use);
1990 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
1991 return;
1992
1993 case COND_EXPR:
1994 case VEC_COND_EXPR:
1995 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), opf_use);
1996 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), opf_use);
1997 get_expr_operands (stmt, &TREE_OPERAND (expr, 2), opf_use);
1998 return;
1999
2000 case CONSTRUCTOR:
2001 {
2002 /* General aggregate CONSTRUCTORs have been decomposed, but they
2003 are still in use as the COMPLEX_EXPR equivalent for vectors. */
2004 constructor_elt *ce;
2005 unsigned HOST_WIDE_INT idx;
2006
2007 for (idx = 0;
2008 VEC_iterate (constructor_elt, CONSTRUCTOR_ELTS (expr), idx, ce);
2009 idx++)
2010 get_expr_operands (stmt, &ce->value, opf_use);
2011
2012 return;
2013 }
2014
2015 case BIT_FIELD_REF:
2016 if (TREE_THIS_VOLATILE (expr))
2017 gimple_set_has_volatile_ops (stmt, true);
2018 /* FALLTHRU */
2019
2020 case TRUTH_NOT_EXPR:
2021 case VIEW_CONVERT_EXPR:
2022 do_unary:
2023 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2024 return;
2025
2026 case TRUTH_AND_EXPR:
2027 case TRUTH_OR_EXPR:
2028 case TRUTH_XOR_EXPR:
2029 case COMPOUND_EXPR:
2030 case OBJ_TYPE_REF:
2031 case ASSERT_EXPR:
2032 do_binary:
2033 {
2034 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2035 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), flags);
2036 return;
2037 }
2038
2039 case DOT_PROD_EXPR:
2040 case REALIGN_LOAD_EXPR:
2041 {
2042 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2043 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), flags);
2044 get_expr_operands (stmt, &TREE_OPERAND (expr, 2), flags);
2045 return;
2046 }
2047
2048 case CHANGE_DYNAMIC_TYPE_EXPR:
2049 gcc_unreachable ();
2050
2051 case FUNCTION_DECL:
2052 case LABEL_DECL:
2053 case CONST_DECL:
2054 case CASE_LABEL_EXPR:
2055 case FILTER_EXPR:
2056 case EXC_PTR_EXPR:
2057 /* Expressions that make no memory references. */
2058 return;
2059
2060 default:
2061 if (codeclass == tcc_unary)
2062 goto do_unary;
2063 if (codeclass == tcc_binary || codeclass == tcc_comparison)
2064 goto do_binary;
2065 if (codeclass == tcc_constant || codeclass == tcc_type)
2066 return;
2067 }
2068
2069 /* If we get here, something has gone wrong. */
2070#ifdef ENABLE_CHECKING
2071 fprintf (stderr, "unhandled expression in get_expr_operands():\n");
2072 debug_tree (expr);
2073 fputs ("\n", stderr);
2074#endif
2075 gcc_unreachable ();
2076}
2077
2078
2079/* Parse STMT looking for operands. When finished, the various
2080 build_* operand vectors will have potential operands in them. */
2081
2082static void
2083parse_ssa_operands (gimple stmt)
2084{
2085 enum gimple_code code = gimple_code (stmt);
2086
2087 if (code == GIMPLE_ASM)
2088 get_asm_expr_operands (stmt);
2089 else
2090 {
2091 size_t i, start = 0;
2092
2093 if (code == GIMPLE_ASSIGN || code == GIMPLE_CALL)
2094 {
2095 get_expr_operands (stmt, gimple_op_ptr (stmt, 0), opf_def);
2096 start = 1;
2097 }
2098
2099 for (i = start; i < gimple_num_ops (stmt); i++)
2100 get_expr_operands (stmt, gimple_op_ptr (stmt, i), opf_use);
2101
2102 /* Add call-clobbered operands, if needed. */
2103 if (code == GIMPLE_CALL)
2104 maybe_add_call_clobbered_vops (stmt);
2105
2106 /* Make sure the return value is addressable in case of NRV. */
2107 if (code == GIMPLE_CALL
2108 && gimple_call_lhs (stmt) != NULL_TREE
2109 && gimple_call_return_slot_opt_p (stmt)
2110 && TREE_ADDRESSABLE (TREE_TYPE (gimple_call_lhs (stmt))))
2111 gimple_add_to_addresses_taken (stmt, gimple_call_lhs (stmt));
2112 }
2113}
2114
2115
2116/* Create an operands cache for STMT. */
2117
2118static void
2119build_ssa_operands (gimple stmt)
2120{
2121 /* Initially assume that the statement has no volatile operands and
2122 makes no memory references. */
2123 gimple_set_has_volatile_ops (stmt, false);
2124 gimple_set_references_memory (stmt, false);
2125
2126 /* Just clear the bitmap so we don't end up reallocating it over and over. */
2127 if (gimple_addresses_taken (stmt))
2128 bitmap_clear (gimple_addresses_taken (stmt));
2129
2130 start_ssa_stmt_operands ();
2131 parse_ssa_operands (stmt);
2132 operand_build_sort_virtual (build_vuses);
2133 operand_build_sort_virtual (build_vdefs);
2134 finalize_ssa_stmt_operands (stmt);
2135
2136 /* For added safety, assume that statements with volatile operands
2137 also reference memory. */
2138 if (gimple_has_volatile_ops (stmt))
2139 gimple_set_references_memory (stmt, true);
2140}
2141
2142
2143/* Releases the operands of STMT back to their freelists, and clears
2144 the stmt operand lists. */
2145
2146void
2147free_stmt_operands (gimple stmt)
2148{
2149 def_optype_p defs = gimple_def_ops (stmt), last_def;
2150 use_optype_p uses = gimple_use_ops (stmt), last_use;
2151 voptype_p vuses = gimple_vuse_ops (stmt);
2152 voptype_p vdefs = gimple_vdef_ops (stmt), vdef, next_vdef;
2153 unsigned i;
2154
2155 if (defs)
2156 {
2157 for (last_def = defs; last_def->next; last_def = last_def->next)
2158 continue;
2159 last_def->next = gimple_ssa_operands (cfun)->free_defs;
2160 gimple_ssa_operands (cfun)->free_defs = defs;
2161 gimple_set_def_ops (stmt, NULL);
2162 }
2163
2164 if (uses)
2165 {
2166 for (last_use = uses; last_use->next; last_use = last_use->next)
2167 delink_imm_use (USE_OP_PTR (last_use));
2168 delink_imm_use (USE_OP_PTR (last_use));
2169 last_use->next = gimple_ssa_operands (cfun)->free_uses;
2170 gimple_ssa_operands (cfun)->free_uses = uses;
2171 gimple_set_use_ops (stmt, NULL);
2172 }
2173
2174 if (vuses)
2175 {
2176 for (i = 0; i < VUSE_NUM (vuses); i++)
2177 delink_imm_use (VUSE_OP_PTR (vuses, i));
2178 add_vop_to_freelist (vuses);
2179 gimple_set_vuse_ops (stmt, NULL);
2180 }
2181
2182 if (vdefs)
2183 {
2184 for (vdef = vdefs; vdef; vdef = next_vdef)
2185 {
2186 next_vdef = vdef->next;
2187 delink_imm_use (VDEF_OP_PTR (vdef, 0));
2188 add_vop_to_freelist (vdef);
2189 }
2190 gimple_set_vdef_ops (stmt, NULL);
2191 }
2192
2193 if (gimple_has_ops (stmt))
2194 gimple_set_addresses_taken (stmt, NULL);
2195
2196 if (gimple_has_mem_ops (stmt))
2197 {
2198 gimple_set_stored_syms (stmt, NULL, &operands_bitmap_obstack);
2199 gimple_set_loaded_syms (stmt, NULL, &operands_bitmap_obstack);
2200 }
2201}
2202
2203
2204/* Get the operands of statement STMT. */
2205
2206void
2207update_stmt_operands (gimple stmt)
2208{
2209 /* If update_stmt_operands is called before SSA is initialized, do
2210 nothing. */
2211 if (!ssa_operands_active ())
2212 return;
2213
2214 timevar_push (TV_TREE_OPS);
2215
2216 gcc_assert (gimple_modified_p (stmt));
2217 build_ssa_operands (stmt);
2218 gimple_set_modified (stmt, false);
2219
2220 timevar_pop (TV_TREE_OPS);
2221}
2222
2223
2224/* Copies virtual operands from SRC to DST. */
2225
2226void
2227copy_virtual_operands (gimple dest, gimple src)
2228{
2229 unsigned int i, n;
2230 voptype_p src_vuses, dest_vuses;
2231 voptype_p src_vdefs, dest_vdefs;
2232 struct voptype_d vuse;
2233 struct voptype_d vdef;
2234
2235 if (!gimple_has_mem_ops (src))
2236 return;
2237
2238 gimple_set_vdef_ops (dest, NULL);
2239 gimple_set_vuse_ops (dest, NULL);
2240
2241 gimple_set_stored_syms (dest, gimple_stored_syms (src),
2242 &operands_bitmap_obstack);
2243 gimple_set_loaded_syms (dest, gimple_loaded_syms (src),
2244 &operands_bitmap_obstack);
2245
2246 /* Copy all the VUSE operators and corresponding operands. */
2247 dest_vuses = &vuse;
2248 for (src_vuses = gimple_vuse_ops (src);
2249 src_vuses;
2250 src_vuses = src_vuses->next)
2251 {
2252 n = VUSE_NUM (src_vuses);
2253 dest_vuses = add_vuse_op (dest, NULL_TREE, n, dest_vuses);
2254 for (i = 0; i < n; i++)
2255 SET_USE (VUSE_OP_PTR (dest_vuses, i), VUSE_OP (src_vuses, i));
2256
2257 if (gimple_vuse_ops (dest) == NULL)
2258 gimple_set_vuse_ops (dest, vuse.next);
2259 }
2260
2261 /* Copy all the VDEF operators and corresponding operands. */
2262 dest_vdefs = &vdef;
2263 for (src_vdefs = gimple_vdef_ops (src);
2264 src_vdefs;
2265 src_vdefs = src_vdefs->next)
2266 {
2267 n = VUSE_NUM (src_vdefs);
2268 dest_vdefs = add_vdef_op (dest, NULL_TREE, n, dest_vdefs);
2269 VDEF_RESULT (dest_vdefs) = VDEF_RESULT (src_vdefs);
2270 for (i = 0; i < n; i++)
2271 SET_USE (VUSE_OP_PTR (dest_vdefs, i), VUSE_OP (src_vdefs, i));
2272
2273 if (gimple_vdef_ops (dest) == NULL)
2274 gimple_set_vdef_ops (dest, vdef.next);
2275 }
2276}
2277
2278
2279/* Specifically for use in DOM's expression analysis. Given a store, we
2280 create an artificial stmt which looks like a load from the store, this can
2281 be used to eliminate redundant loads. OLD_OPS are the operands from the
2282 store stmt, and NEW_STMT is the new load which represents a load of the
2283 values stored. If DELINK_IMM_USES_P is specified, the immediate
2284 uses of this stmt will be de-linked. */
2285
2286void
2287create_ssa_artificial_load_stmt (gimple new_stmt, gimple old_stmt,
2288 bool delink_imm_uses_p)
2289{
2290 tree op;
2291 ssa_op_iter iter;
2292 use_operand_p use_p;
2293 unsigned i;
2294
2295 gimple_set_modified (new_stmt, false);
2296
2297 /* Process NEW_STMT looking for operands. */
2298 start_ssa_stmt_operands ();
2299 parse_ssa_operands (new_stmt);
2300
2301 for (i = 0; VEC_iterate (tree, build_vuses, i, op); i++)
2302 if (TREE_CODE (op) != SSA_NAME)
2303 var_ann (op)->in_vuse_list = false;
2304
2305 for (i = 0; VEC_iterate (tree, build_vdefs, i, op); i++)
2306 if (TREE_CODE (op) != SSA_NAME)
2307 var_ann (op)->in_vdef_list = false;
2308
2309 /* Remove any virtual operands that were found. */
2310 VEC_truncate (tree, build_vdefs, 0);
2311 VEC_truncate (tree, build_vuses, 0);
2312
2313 /* Clear the loads and stores bitmaps. */
2314 bitmap_clear (build_loads);
2315 bitmap_clear (build_stores);
2316
2317 /* For each VDEF on the original statement, we want to create a
2318 VUSE of the VDEF result operand on the new statement. */
2319 FOR_EACH_SSA_TREE_OPERAND (op, old_stmt, iter, SSA_OP_VDEF)
2320 append_vuse (op);
2321
2322 finalize_ssa_stmt_operands (new_stmt);
2323
2324 /* All uses in this fake stmt must not be in the immediate use lists. */
2325 if (delink_imm_uses_p)
2326 FOR_EACH_SSA_USE_OPERAND (use_p, new_stmt, iter, SSA_OP_ALL_USES)
2327 delink_imm_use (use_p);
2328}
2329
2330
2331/* Swap operands EXP0 and EXP1 in statement STMT. No attempt is done
2332 to test the validity of the swap operation. */
2333
2334void
2335swap_tree_operands (gimple stmt, tree *exp0, tree *exp1)
2336{
2337 tree op0, op1;
2338 op0 = *exp0;
2339 op1 = *exp1;
2340
2341 /* If the operand cache is active, attempt to preserve the relative
2342 positions of these two operands in their respective immediate use
2343 lists. */
2344 if (ssa_operands_active () && op0 != op1)
2345 {
2346 use_optype_p use0, use1, ptr;
2347 use0 = use1 = NULL;
2348
2349 /* Find the 2 operands in the cache, if they are there. */
2350 for (ptr = gimple_use_ops (stmt); ptr; ptr = ptr->next)
2351 if (USE_OP_PTR (ptr)->use == exp0)
2352 {
2353 use0 = ptr;
2354 break;
2355 }
2356
2357 for (ptr = gimple_use_ops (stmt); ptr; ptr = ptr->next)
2358 if (USE_OP_PTR (ptr)->use == exp1)
2359 {
2360 use1 = ptr;
2361 break;
2362 }
2363
2364 /* If both uses don't have operand entries, there isn't much we can do
2365 at this point. Presumably we don't need to worry about it. */
2366 if (use0 && use1)
2367 {
2368 tree *tmp = USE_OP_PTR (use1)->use;
2369 USE_OP_PTR (use1)->use = USE_OP_PTR (use0)->use;
2370 USE_OP_PTR (use0)->use = tmp;
2371 }
2372 }
2373
2374 /* Now swap the data. */
2375 *exp0 = op1;
2376 *exp1 = op0;
2377}
2378
2379/* Add the base address of REF to SET. */
2380
2381void
2382add_to_addressable_set (tree ref, bitmap *set)
2383{
2384 tree var;
2385
2386 /* Note that it is *NOT OKAY* to use the target of a COMPONENT_REF
2387 as the only thing we take the address of. If VAR is a structure,
2388 taking the address of a field means that the whole structure may
2389 be referenced using pointer arithmetic. See PR 21407 and the
2390 ensuing mailing list discussion. */
2391 var = get_base_address (ref);
2392 if (var && SSA_VAR_P (var))
2393 {
2394 if (*set == NULL)
2395 *set = BITMAP_ALLOC (&operands_bitmap_obstack);
2396
2397 bitmap_set_bit (*set, DECL_UID (var));
2398 TREE_ADDRESSABLE (var) = 1;
2399 }
2400}
2401
2402
2403/* Add the base address of REF to the set of addresses taken by STMT.
2404 REF may be a single variable whose address has been taken or any
2405 other valid GIMPLE memory reference (structure reference, array,
2406 etc). If the base address of REF is a decl that has sub-variables,
2407 also add all of its sub-variables. */
2408
2409void
2410gimple_add_to_addresses_taken (gimple stmt, tree ref)
2411{
2412 gcc_assert (gimple_has_ops (stmt));
2413 add_to_addressable_set (ref, gimple_addresses_taken_ptr (stmt));
2414}
2415
2416
2417/* Scan the immediate_use list for VAR making sure its linked properly.
2418 Return TRUE if there is a problem and emit an error message to F. */
2419
2420bool
2421verify_imm_links (FILE *f, tree var)
2422{
2423 use_operand_p ptr, prev, list;
2424 int count;
2425
2426 gcc_assert (TREE_CODE (var) == SSA_NAME);
2427
2428 list = &(SSA_NAME_IMM_USE_NODE (var));
2429 gcc_assert (list->use == NULL);
2430
2431 if (list->prev == NULL)
2432 {
2433 gcc_assert (list->next == NULL);
2434 return false;
2435 }
2436
2437 prev = list;
2438 count = 0;
2439 for (ptr = list->next; ptr != list; )
2440 {
2441 if (prev != ptr->prev)
2442 goto error;
2443
2444 if (ptr->use == NULL)
2445 goto error; /* 2 roots, or SAFE guard node. */
2446 else if (*(ptr->use) != var)
2447 goto error;
2448
2449 prev = ptr;
2450 ptr = ptr->next;
2451
2452 /* Avoid infinite loops. 50,000,000 uses probably indicates a
2453 problem. */
2454 if (count++ > 50000000)
2455 goto error;
2456 }
2457
2458 /* Verify list in the other direction. */
2459 prev = list;
2460 for (ptr = list->prev; ptr != list; )
2461 {
2462 if (prev != ptr->next)
2463 goto error;
2464 prev = ptr;
2465 ptr = ptr->prev;
2466 if (count-- < 0)
2467 goto error;
2468 }
2469
2470 if (count != 0)
2471 goto error;
2472
2473 return false;
2474
2475 error:
2476 if (ptr->loc.stmt && gimple_modified_p (ptr->loc.stmt))
2477 {
2478 fprintf (f, " STMT MODIFIED. - <%p> ", (void *)ptr->loc.stmt);
2479 print_gimple_stmt (f, ptr->loc.stmt, 0, TDF_SLIM);
2480 }
2481 fprintf (f, " IMM ERROR : (use_p : tree - %p:%p)", (void *)ptr,
2482 (void *)ptr->use);
2483 print_generic_expr (f, USE_FROM_PTR (ptr), TDF_SLIM);
2484 fprintf(f, "\n");
2485 return true;
2486}
2487
2488
2489/* Dump all the immediate uses to FILE. */
2490
2491void
2492dump_immediate_uses_for (FILE *file, tree var)
2493{
2494 imm_use_iterator iter;
2495 use_operand_p use_p;
2496
2497 gcc_assert (var && TREE_CODE (var) == SSA_NAME);
2498
2499 print_generic_expr (file, var, TDF_SLIM);
2500 fprintf (file, " : -->");
2501 if (has_zero_uses (var))
2502 fprintf (file, " no uses.\n");
2503 else
2504 if (has_single_use (var))
2505 fprintf (file, " single use.\n");
2506 else
2507 fprintf (file, "%d uses.\n", num_imm_uses (var));
2508
2509 FOR_EACH_IMM_USE_FAST (use_p, iter, var)
2510 {
2511 if (use_p->loc.stmt == NULL && use_p->use == NULL)
2512 fprintf (file, "***end of stmt iterator marker***\n");
2513 else
2514 if (!is_gimple_reg (USE_FROM_PTR (use_p)))
2515 print_gimple_stmt (file, USE_STMT (use_p), 0, TDF_VOPS|TDF_MEMSYMS);
2516 else
2517 print_gimple_stmt (file, USE_STMT (use_p), 0, TDF_SLIM);
2518 }
2519 fprintf(file, "\n");
2520}
2521
2522
2523/* Dump all the immediate uses to FILE. */
2524
2525void
2526dump_immediate_uses (FILE *file)
2527{
2528 tree var;
2529 unsigned int x;
2530
2531 fprintf (file, "Immediate_uses: \n\n");
2532 for (x = 1; x < num_ssa_names; x++)
2533 {
2534 var = ssa_name(x);
2535 if (!var)
2536 continue;
2537 dump_immediate_uses_for (file, var);
2538 }
2539}
2540
2541
2542/* Dump def-use edges on stderr. */
2543
2544void
2545debug_immediate_uses (void)
2546{
2547 dump_immediate_uses (stderr);
2548}
2549
2550
2551/* Dump def-use edges on stderr. */
2552
2553void
2554debug_immediate_uses_for (tree var)
2555{
2556 dump_immediate_uses_for (stderr, var);
2557}
2558
2559
2560/* Create a new change buffer for the statement pointed by STMT_P and
2561 push the buffer into SCB_STACK. Each change buffer
2562 records state information needed to determine what changed in the
2563 statement. Mainly, this keeps track of symbols that may need to be
2564 put into SSA form, SSA name replacements and other information
2565 needed to keep the SSA form up to date. */
2566
2567void
2568push_stmt_changes (gimple *stmt_p)
2569{
2570 gimple stmt;
2571 scb_t buf;
2572
2573 stmt = *stmt_p;
2574
2575 /* It makes no sense to keep track of PHI nodes. */
2576 if (gimple_code (stmt) == GIMPLE_PHI)
2577 return;
2578
2579 buf = XNEW (struct scb_d);
2580 memset (buf, 0, sizeof *buf);
2581
2582 buf->stmt_p = stmt_p;
2583
2584 if (gimple_references_memory_p (stmt))
2585 {
2586 tree op;
2587 ssa_op_iter i;
2588
2589 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_VUSE)
2590 {
2591 tree sym = TREE_CODE (op) == SSA_NAME ? SSA_NAME_VAR (op) : op;
2592 if (buf->loads == NULL)
2593 buf->loads = BITMAP_ALLOC (NULL);
2594 bitmap_set_bit (buf->loads, DECL_UID (sym));
2595 }
2596
2597 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_VDEF)
2598 {
2599 tree sym = TREE_CODE (op) == SSA_NAME ? SSA_NAME_VAR (op) : op;
2600 if (buf->stores == NULL)
2601 buf->stores = BITMAP_ALLOC (NULL);
2602 bitmap_set_bit (buf->stores, DECL_UID (sym));
2603 }
2604 }
2605
2606 VEC_safe_push (scb_t, heap, scb_stack, buf);
2607}
2608
2609
2610/* Given two sets S1 and S2, mark the symbols that differ in S1 and S2
2611 for renaming. The set to mark for renaming is (S1 & ~S2) | (S2 & ~S1). */
2612
2613static void
2614mark_difference_for_renaming (bitmap s1, bitmap s2)
2615{
2616 if (s1 == NULL && s2 == NULL)
2617 return;
2618
2619 if (s1 && s2 == NULL)
2620 mark_set_for_renaming (s1);
2621 else if (s1 == NULL && s2)
2622 mark_set_for_renaming (s2);
2623 else if (!bitmap_equal_p (s1, s2))
2624 {
2625 bitmap t1 = BITMAP_ALLOC (NULL);
2626 bitmap_xor (t1, s1, s2);
2627 mark_set_for_renaming (t1);
2628 BITMAP_FREE (t1);
2629 }
2630}
2631
2632
2633/* Pop the top SCB from SCB_STACK and act on the differences between
2634 what was recorded by push_stmt_changes and the current state of
2635 the statement. */
2636
2637void
2638pop_stmt_changes (gimple *stmt_p)
2639{
2640 tree op;
2641 gimple stmt;
2642 ssa_op_iter iter;
2643 bitmap loads, stores;
2644 scb_t buf;
2645
2646 stmt = *stmt_p;
2647
2648 /* It makes no sense to keep track of PHI nodes. */
2649 if (gimple_code (stmt) == GIMPLE_PHI)
2650 return;
2651
2652 buf = VEC_pop (scb_t, scb_stack);
2653 gcc_assert (stmt_p == buf->stmt_p);
2654
2655 /* Force an operand re-scan on the statement and mark any newly
2656 exposed variables. */
2657 update_stmt (stmt);
2658
2659 /* Determine whether any memory symbols need to be renamed. If the
2660 sets of loads and stores are different after the statement is
2661 modified, then the affected symbols need to be renamed.
2662
2663 Note that it may be possible for the statement to not reference
2664 memory anymore, but we still need to act on the differences in
2665 the sets of symbols. */
2666 loads = stores = NULL;
2667 if (gimple_references_memory_p (stmt))
2668 {
2669 tree op;
2670 ssa_op_iter i;
2671
2672 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_VUSE)
2673 {
2674 tree sym = TREE_CODE (op) == SSA_NAME ? SSA_NAME_VAR (op) : op;
2675 if (loads == NULL)
2676 loads = BITMAP_ALLOC (NULL);
2677 bitmap_set_bit (loads, DECL_UID (sym));
2678 }
2679
2680 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_VDEF)
2681 {
2682 tree sym = TREE_CODE (op) == SSA_NAME ? SSA_NAME_VAR (op) : op;
2683 if (stores == NULL)
2684 stores = BITMAP_ALLOC (NULL);
2685 bitmap_set_bit (stores, DECL_UID (sym));
2686 }
2687 }
2688
2689 /* If LOADS is different from BUF->LOADS, the affected
2690 symbols need to be marked for renaming. */
2691 mark_difference_for_renaming (loads, buf->loads);
2692
2693 /* Similarly for STORES and BUF->STORES. */
2694 mark_difference_for_renaming (stores, buf->stores);
2695
2696 /* Mark all the naked GIMPLE register operands for renaming. */
2697 FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_DEF|SSA_OP_USE)
2698 if (DECL_P (op))
2699 mark_sym_for_renaming (op);
2700
2701 /* FIXME, need to add more finalizers here. Cleanup EH info,
2702 recompute invariants for address expressions, add
2703 SSA replacement mappings, etc. For instance, given
2704 testsuite/gcc.c-torture/compile/pr16808.c, we fold a statement of
2705 the form:
2706
2707 # SMT.4_20 = VDEF <SMT.4_16>
2708 D.1576_11 = 1.0e+0;
2709
2710 So, the VDEF will disappear, but instead of marking SMT.4 for
2711 renaming it would be far more efficient to establish a
2712 replacement mapping that would replace every reference of
2713 SMT.4_20 with SMT.4_16. */
2714
2715 /* Free memory used by the buffer. */
2716 BITMAP_FREE (buf->loads);
2717 BITMAP_FREE (buf->stores);
2718 BITMAP_FREE (loads);
2719 BITMAP_FREE (stores);
2720 buf->stmt_p = NULL;
2721 free (buf);
2722}
2723
2724
2725/* Discard the topmost change buffer from SCB_STACK. This is useful
2726 when the caller realized that it did not actually modified the
2727 statement. It avoids the expensive operand re-scan. */
2728
2729void
2730discard_stmt_changes (gimple *stmt_p)
2731{
2732 scb_t buf;
2733 gimple stmt;
2734
2735 /* It makes no sense to keep track of PHI nodes. */
2736 stmt = *stmt_p;
2737 if (gimple_code (stmt) == GIMPLE_PHI)
2738 return;
2739
2740 buf = VEC_pop (scb_t, scb_stack);
2741 gcc_assert (stmt_p == buf->stmt_p);
2742
2743 /* Free memory used by the buffer. */
2744 BITMAP_FREE (buf->loads);
2745 BITMAP_FREE (buf->stores);
2746 buf->stmt_p = NULL;
2747 free (buf);
2748}