2008-11-19 Andrew Stubbs <ams@codesourcery.com>
[official-gcc.git] / gcc / tree-ssa-operands.c
blob962418895385dcdd525244b7e796b7e33a6fb9ab
1 /* SSA operands management for trees.
2 Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008
3 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3, or (at your option)
10 any later version.
12 GCC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
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"
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.
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.
50 The routines in this file are concerned with creating this operand cache
51 from a stmt tree.
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.
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.
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.
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.
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'. */
78 /* Helper functions from gimple.c. These are GIMPLE manipulation
79 routines that only the operand scanner should need. */
80 void gimple_set_stored_syms (gimple, bitmap, bitmap_obstack *);
81 void gimple_set_loaded_syms (gimple, bitmap, bitmap_obstack *);
83 /* Structure storing statistics on how many call clobbers we have, and
84 how many where avoided. */
86 static struct
88 /* Number of call-clobbered ops we attempt to add to calls in
89 add_call_clobbered_mem_symbols. */
90 unsigned int clobbered_vars;
92 /* Number of write-clobbers (VDEFs) avoided by using
93 not_written information. */
94 unsigned int static_write_clobbers_avoided;
96 /* Number of reads (VUSEs) avoided by using not_read information. */
97 unsigned int static_read_clobbers_avoided;
99 /* Number of write-clobbers avoided because the variable can't escape to
100 this call. */
101 unsigned int unescapable_clobbers_avoided;
103 /* Number of read-only uses we attempt to add to calls in
104 add_call_read_mem_symbols. */
105 unsigned int readonly_clobbers;
107 /* Number of read-only uses we avoid using not_read information. */
108 unsigned int static_readonly_clobbers_avoided;
109 } clobber_stats;
112 /* Flags to describe operand properties in helpers. */
114 /* By default, operands are loaded. */
115 #define opf_use 0
117 /* Operand is the target of an assignment expression or a
118 call-clobbered variable. */
119 #define opf_def (1 << 0)
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)
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)
134 /* Array for building all the def operands. */
135 static VEC(tree,heap) *build_defs;
137 /* Array for building all the use operands. */
138 static VEC(tree,heap) *build_uses;
140 /* Set for building all the VDEF operands. */
141 static VEC(tree,heap) *build_vdefs;
143 /* Set for building all the VUSE operands. */
144 static VEC(tree,heap) *build_vuses;
146 /* Bitmap obstack for our datastructures that needs to survive across
147 compilations of multiple functions. */
148 static bitmap_obstack operands_bitmap_obstack;
150 /* Set for building all the loaded symbols. */
151 static bitmap build_loads;
153 /* Set for building all the stored symbols. */
154 static bitmap build_stores;
156 static void get_expr_operands (gimple, tree *, int);
158 /* Number of functions with initialized ssa_operands. */
159 static int n_initialized = 0;
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:
168 1- Call push_stmt_changes (&stmt) to record the current state of
169 STMT before any modifications are made.
171 2- Make all appropriate modifications to the statement.
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.
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. */
183 struct scb_d
185 /* Pointer to the statement being modified. */
186 gimple *stmt_p;
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;
194 typedef struct scb_d *scb_t;
195 DEF_VEC_P(scb_t);
196 DEF_VEC_ALLOC_P(scb_t,heap);
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. */
202 static VEC(scb_t,heap) *scb_stack;
204 /* Return the DECL_UID of the base variable of T. */
206 static inline unsigned
207 get_name_decl (const_tree t)
209 if (TREE_CODE (t) != SSA_NAME)
210 return DECL_UID (t);
211 else
212 return DECL_UID (SSA_NAME_VAR (t));
216 /* Comparison function for qsort used in operand_build_sort_virtual. */
219 operand_build_cmp (const void *p, const void *q)
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);
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);
234 /* Sort the virtual operands in LIST from lowest DECL_UID to highest. */
236 static inline void
237 operand_build_sort_virtual (VEC(tree,heap) *list)
239 int num = VEC_length (tree, list);
241 if (num < 2)
242 return;
244 if (num == 2)
246 if (get_name_decl (VEC_index (tree, list, 0))
247 > get_name_decl (VEC_index (tree, list, 1)))
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);
254 return;
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);
264 /* Return true if the SSA operands cache is active. */
266 bool
267 ssa_operands_active (void)
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;
276 return cfun->gimple_df && gimple_ssa_operands (cfun)->ops_active;
280 /* VOPs are of variable sized, so the free list maps "free buckets" to the
281 following table:
282 bucket # operands
283 ------ ----------
287 15 16
288 16 17-24
289 17 25-32
290 18 31-40
292 29 121-128
293 Any VOPs larger than this are simply added to the largest bucket when they
294 are freed. */
297 /* Return the number of operands used in bucket BUCKET. */
299 static inline int
300 vop_free_bucket_size (int bucket)
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;
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. */
314 static inline int
315 vop_free_bucket_index (int num)
317 gcc_assert (num > 0 && NUM_VOP_FREE_BUCKETS > 16);
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;
331 /* Initialize the VOP free buckets. */
333 static inline void
334 init_vop_buckets (void)
336 int x;
338 for (x = 0; x < NUM_VOP_FREE_BUCKETS; x++)
339 gimple_ssa_operands (cfun)->vop_free_buckets[x] = NULL;
343 /* Add PTR to the appropriate VOP bucket. */
345 static inline void
346 add_vop_to_freelist (voptype_p ptr)
348 int bucket = vop_free_bucket_index (VUSE_VECT_NUM_ELEM (ptr->usev));
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;
354 ptr->next = gimple_ssa_operands (cfun)->vop_free_buckets[bucket];
355 gimple_ssa_operands (cfun)->vop_free_buckets[bucket] = ptr;
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. */
363 #define OP_SIZE_INIT 0
364 #define OP_SIZE_1 30
365 #define OP_SIZE_2 110
366 #define OP_SIZE_3 511
368 /* Initialize the operand cache routines. */
370 void
371 init_ssa_operands (void)
373 if (!n_initialized++)
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);
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;
396 /* Dispose of anything required by the operand routines. */
398 void
399 fini_ssa_operands (void)
401 struct ssa_operand_memory_d *ptr;
402 unsigned ix;
403 tree mpt;
405 if (!--n_initialized)
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);
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;
420 gimple_ssa_operands (cfun)->free_defs = NULL;
421 gimple_ssa_operands (cfun)->free_uses = NULL;
423 while ((ptr = gimple_ssa_operands (cfun)->operand_memory) != NULL)
425 gimple_ssa_operands (cfun)->operand_memory
426 = gimple_ssa_operands (cfun)->operand_memory->next;
427 ggc_free (ptr);
430 for (ix = 0;
431 VEC_iterate (tree, gimple_ssa_operands (cfun)->mpt_table, ix, mpt);
432 ix++)
434 if (mpt)
435 BITMAP_FREE (MPT_SYMBOLS (mpt));
438 VEC_free (tree, heap, gimple_ssa_operands (cfun)->mpt_table);
440 gimple_ssa_operands (cfun)->ops_active = false;
442 if (!n_initialized)
443 bitmap_obstack_release (&operands_bitmap_obstack);
445 if (dump_file && (dump_flags & TDF_STATS))
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);
463 /* Return memory for operands of SIZE chunks. */
465 static inline void *
466 ssa_operand_alloc (unsigned size)
468 char *ptr;
470 if (gimple_ssa_operands (cfun)->operand_memory_index + size
471 >= gimple_ssa_operands (cfun)->ssa_operand_mem_size)
473 struct ssa_operand_memory_d *ptr;
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);
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);
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;
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;
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;
511 /* Allocate a DEF operand. */
513 static inline struct def_optype_d *
514 alloc_def (void)
516 struct def_optype_d *ret;
517 if (gimple_ssa_operands (cfun)->free_defs)
519 ret = gimple_ssa_operands (cfun)->free_defs;
520 gimple_ssa_operands (cfun)->free_defs
521 = gimple_ssa_operands (cfun)->free_defs->next;
523 else
524 ret = (struct def_optype_d *)
525 ssa_operand_alloc (sizeof (struct def_optype_d));
526 return ret;
530 /* Allocate a USE operand. */
532 static inline struct use_optype_d *
533 alloc_use (void)
535 struct use_optype_d *ret;
536 if (gimple_ssa_operands (cfun)->free_uses)
538 ret = gimple_ssa_operands (cfun)->free_uses;
539 gimple_ssa_operands (cfun)->free_uses
540 = gimple_ssa_operands (cfun)->free_uses->next;
542 else
543 ret = (struct use_optype_d *)
544 ssa_operand_alloc (sizeof (struct use_optype_d));
545 return ret;
549 /* Allocate a vop with NUM elements. */
551 static inline struct voptype_d *
552 alloc_vop (int num)
554 struct voptype_d *ret = NULL;
555 int alloc_size = 0;
557 int bucket = vop_free_bucket_index (num);
558 if (bucket != -1)
560 /* If there is a free operand, use it. */
561 if (gimple_ssa_operands (cfun)->vop_free_buckets[bucket] != NULL)
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;
567 else
568 alloc_size = vop_free_bucket_size(bucket);
570 else
571 alloc_size = num;
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));
577 VUSE_VECT_NUM_ELEM (ret->usev) = num;
578 return ret;
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. */
585 static inline void
586 set_virtual_use_link (use_operand_p ptr, gimple stmt)
588 /* fold_stmt may have changed the stmt pointers. */
589 if (ptr->loc.stmt != stmt)
590 ptr->loc.stmt = stmt;
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));
598 /* Adds OP to the list of defs after LAST. */
600 static inline def_optype_p
601 add_def_op (tree *op, def_optype_p last)
603 def_optype_p new_def;
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;
613 /* Adds OP to the list of uses of statement STMT after LAST. */
615 static inline use_optype_p
616 add_use_op (gimple stmt, tree *op, use_optype_p last)
618 use_optype_p new_use;
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;
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. */
633 static inline voptype_p
634 add_vop (gimple stmt, tree op, int num, voptype_p prev)
636 voptype_p new_vop;
637 int x;
639 new_vop = alloc_vop (num);
640 for (x = 0; x < num; x++)
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);
649 if (prev)
650 prev->next = new_vop;
651 new_vop->next = NULL;
652 return new_vop;
656 /* Adds OP to the list of vuses of statement STMT after LAST, and moves
657 LAST to the new element. */
659 static inline voptype_p
660 add_vuse_op (gimple stmt, tree op, int num, voptype_p last)
662 voptype_p new_vop = add_vop (stmt, op, num, last);
663 VDEF_RESULT (new_vop) = NULL_TREE;
664 return new_vop;
668 /* Adds OP to the list of vdefs of statement STMT after LAST, and moves
669 LAST to the new element. */
671 static inline voptype_p
672 add_vdef_op (gimple stmt, tree op, int num, voptype_p last)
674 voptype_p new_vop = add_vop (stmt, op, num, last);
675 VDEF_RESULT (new_vop) = op;
676 return new_vop;
680 /* Takes elements from build_defs and turns them into def operands of STMT.
681 TODO -- Make build_defs VEC of tree *. */
683 static inline void
684 finalize_ssa_defs (gimple stmt)
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);
691 /* There should only be a single real definition per assignment. */
692 gcc_assert ((stmt && gimple_code (stmt) != GIMPLE_ASSIGN) || num <= 1);
694 new_list.next = NULL;
695 last = &new_list;
697 old_ops = gimple_def_ops (stmt);
699 new_i = 0;
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;
706 /* If there is anything in the old list, free it. */
707 if (old_ops)
709 old_ops->next = gimple_ssa_operands (cfun)->free_defs;
710 gimple_ssa_operands (cfun)->free_defs = old_ops;
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);
717 /* Now set the stmt's operands. */
718 gimple_set_def_ops (stmt, new_list.next);
720 #ifdef ENABLE_CHECKING
722 def_optype_p ptr;
723 unsigned x = 0;
724 for (ptr = gimple_def_ops (stmt); ptr; ptr = ptr->next)
725 x++;
727 gcc_assert (x == num);
729 #endif
733 /* Takes elements from build_uses and turns them into use operands of STMT.
734 TODO -- Make build_uses VEC of tree *. */
736 static inline void
737 finalize_ssa_uses (gimple stmt)
739 unsigned new_i;
740 struct use_optype_d new_list;
741 use_optype_p old_ops, ptr, last;
743 new_list.next = NULL;
744 last = &new_list;
746 old_ops = gimple_use_ops (stmt);
748 /* If there is anything in the old list, free it. */
749 if (old_ops)
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;
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);
763 /* Now set the stmt's operands. */
764 gimple_set_use_ops (stmt, new_list.next);
766 #ifdef ENABLE_CHECKING
768 unsigned x = 0;
769 for (ptr = gimple_use_ops (stmt); ptr; ptr = ptr->next)
770 x++;
772 gcc_assert (x == VEC_length (tree, build_uses));
774 #endif
778 /* Takes elements from BUILD_VDEFS and turns them into vdef operands of
779 STMT. */
781 static inline void
782 finalize_ssa_vdefs (gimple stmt)
784 unsigned new_i;
785 struct voptype_d new_list;
786 voptype_p old_ops, ptr, last;
788 /* Set the symbols referenced by STMT. */
789 gimple_set_stored_syms (stmt, build_stores, &operands_bitmap_obstack);
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;
801 new_list.next = NULL;
802 last = &new_list;
804 old_ops = gimple_vdef_ops (stmt);
805 new_i = 0;
806 while (old_ops && new_i < VEC_length (tree, build_vdefs))
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));
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);
816 if (old_uid == new_uid)
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++;
826 else if (old_uid < new_uid)
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;
835 else
837 /* This is a new operand. */
838 last = add_vdef_op (stmt, op, 1, last);
839 new_i++;
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);
847 /* If there is anything in the old list, free it. */
848 if (old_ops)
850 for (ptr = old_ops; ptr; ptr = last)
852 last = ptr->next;
853 delink_imm_use (VDEF_OP_PTR (ptr, 0));
854 add_vop_to_freelist (ptr);
858 /* Now set STMT's operands. */
859 gimple_set_vdef_ops (stmt, new_list.next);
861 #ifdef ENABLE_CHECKING
863 unsigned x = 0;
864 for (ptr = gimple_vdef_ops (stmt); ptr; ptr = ptr->next)
865 x++;
867 gcc_assert (x == VEC_length (tree, build_vdefs));
869 #endif
873 /* Takes elements from BUILD_VUSES and turns them into VUSE operands of
874 STMT. */
876 static inline void
877 finalize_ssa_vuse_ops (gimple stmt)
879 unsigned new_i, old_i;
880 voptype_p old_ops, last;
881 VEC(tree,heap) *new_ops;
883 /* Set the symbols referenced by STMT. */
884 gimple_set_loaded_syms (stmt, build_loads, &operands_bitmap_obstack);
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;
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);
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))
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);
911 if (old_uid == new_uid)
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++;
918 else if (old_uid < new_uid)
920 /* If OLD_UID is less than NEW_UID, the old operand has
921 disappeared, skip to the next old operand. */
922 old_i++;
924 else
926 /* This is a new operand. */
927 VEC_safe_push (tree, heap, new_ops, new_op);
928 new_i++;
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));
936 /* If there is anything in the old list, free it. */
937 if (old_ops)
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);
945 /* If there are any operands, instantiate a VUSE operator for STMT. */
946 if (new_ops)
948 tree op;
949 unsigned i;
951 last = add_vuse_op (stmt, NULL, VEC_length (tree, new_ops), NULL);
953 for (i = 0; VEC_iterate (tree, new_ops, i, op); i++)
954 SET_USE (VUSE_OP_PTR (last, (int) i), op);
956 gimple_set_vuse_ops (stmt, last);
957 VEC_free (tree, heap, new_ops);
960 #ifdef ENABLE_CHECKING
962 unsigned x;
964 if (gimple_vuse_ops (stmt))
966 gcc_assert (gimple_vuse_ops (stmt)->next == NULL);
967 x = VUSE_NUM (gimple_vuse_ops (stmt));
969 else
970 x = 0;
972 gcc_assert (x == VEC_length (tree, build_vuses));
974 #endif
977 /* Return a new VUSE operand vector for STMT. */
979 static void
980 finalize_ssa_vuses (gimple stmt)
982 unsigned num, num_vdefs;
983 unsigned vuse_index;
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:
990 # VUSE <a_2>
991 # a_3 = VDEF <a_2>
992 *p = *q;
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);
999 if (num > 0 && num_vdefs > 0)
1000 for (vuse_index = 0; vuse_index < VEC_length (tree, build_vuses); )
1002 tree vuse;
1003 vuse = VEC_index (tree, build_vuses, vuse_index);
1004 if (TREE_CODE (vuse) != SSA_NAME)
1006 var_ann_t ann = var_ann (vuse);
1007 ann->in_vuse_list = 0;
1008 if (ann->in_vdef_list)
1010 VEC_ordered_remove (tree, build_vuses, vuse_index);
1011 continue;
1014 vuse_index++;
1017 finalize_ssa_vuse_ops (stmt);
1021 /* Clear the in_list bits and empty the build array for VDEFs and
1022 VUSEs. */
1024 static inline void
1025 cleanup_build_arrays (void)
1027 unsigned i;
1028 tree t;
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;
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;
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);
1047 /* Finalize all the build vectors, fill the new ones into INFO. */
1049 static inline void
1050 finalize_ssa_stmt_operands (gimple stmt)
1052 finalize_ssa_defs (stmt);
1053 finalize_ssa_uses (stmt);
1054 if (gimple_has_mem_ops (stmt))
1056 finalize_ssa_vdefs (stmt);
1057 finalize_ssa_vuses (stmt);
1059 cleanup_build_arrays ();
1063 /* Start the process of building up operands vectors in INFO. */
1065 static inline void
1066 start_ssa_stmt_operands (void)
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));
1077 /* Add DEF_P to the list of pointers to operands. */
1079 static inline void
1080 append_def (tree *def_p)
1082 VEC_safe_push (tree, heap, build_defs, (tree) def_p);
1086 /* Add USE_P to the list of pointers to operands. */
1088 static inline void
1089 append_use (tree *use_p)
1091 VEC_safe_push (tree, heap, build_uses, (tree) use_p);
1095 /* Add VAR to the set of variables that require a VDEF operator. */
1097 static inline void
1098 append_vdef (tree var)
1100 tree sym;
1102 if (TREE_CODE (var) != SSA_NAME)
1104 tree mpt;
1105 var_ann_t ann;
1107 /* If VAR belongs to a memory partition, use it instead of VAR. */
1108 mpt = memory_partition (var);
1109 if (mpt)
1110 var = mpt;
1112 /* Don't allow duplicate entries. */
1113 ann = get_var_ann (var);
1114 if (ann->in_vdef_list)
1115 return;
1117 ann->in_vdef_list = true;
1118 sym = var;
1120 else
1121 sym = SSA_NAME_VAR (var);
1123 VEC_safe_push (tree, heap, build_vdefs, var);
1124 bitmap_set_bit (build_stores, DECL_UID (sym));
1128 /* Add VAR to the set of variables that require a VUSE operator. */
1130 static inline void
1131 append_vuse (tree var)
1133 tree sym;
1135 if (TREE_CODE (var) != SSA_NAME)
1137 tree mpt;
1138 var_ann_t ann;
1140 /* If VAR belongs to a memory partition, use it instead of VAR. */
1141 mpt = memory_partition (var);
1142 if (mpt)
1143 var = mpt;
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)
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;
1157 ann->in_vuse_list = true;
1158 sym = var;
1160 else
1161 sym = SSA_NAME_VAR (var);
1163 VEC_safe_push (tree, heap, build_vuses, var);
1164 bitmap_set_bit (build_loads, DECL_UID (sym));
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.
1173 XXX: We should handle the NO_ALIAS attributes here. */
1175 static bool
1176 access_can_touch_variable (tree ref, tree alias, HOST_WIDE_INT offset,
1177 HOST_WIDE_INT size)
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;
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;
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;
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.
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.
1201 Without strict aliasing on, we consider it legal to do something
1202 like:
1204 struct foos { int l; };
1205 int foo;
1206 static struct foos *getfoo(void);
1207 int main (void)
1209 struct foos *f = getfoo();
1210 f->l = 1;
1211 foo = 2;
1212 if (f->l == 1)
1213 abort();
1214 exit(0);
1216 static struct foos *getfoo(void)
1217 { return (struct foos *)&foo; }
1219 (taken from 20000623-1.c)
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
1225 typedef union {
1226 int d;
1227 } U;
1229 int rv;
1230 void breakme()
1232 U *rv0;
1233 U *pretmp = (U*)&rv;
1234 rv0 = pretmp;
1235 rv0->d = 42;
1237 To implement this, we just punt on accesses through union
1238 pointers entirely.
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
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};
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))
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;
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)))
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;
1305 return true;
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. */
1315 static void
1316 add_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)
1320 bitmap aliases = NULL;
1321 tree sym;
1322 var_ann_t v_ann;
1324 sym = (TREE_CODE (var) == SSA_NAME ? SSA_NAME_VAR (var) : var);
1325 v_ann = var_ann (sym);
1327 /* Mark the statement as having memory operands. */
1328 gimple_set_references_memory (stmt, true);
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.
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.
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;
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;
1353 if (MTAG_P (var))
1354 aliases = MTAG_ALIASES (var);
1356 if (aliases == NULL)
1358 if (!gimple_aliases_computed_p (cfun) && (flags & opf_def))
1359 gimple_set_has_volatile_ops (stmt, true);
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);
1367 else
1369 bitmap_iterator bi;
1370 unsigned int i;
1371 bool none_added = true;
1373 /* The variable is aliased. Add its aliases to the virtual
1374 operands. */
1375 gcc_assert (!bitmap_empty_p (aliases));
1377 EXECUTE_IF_SET_IN_BITMAP (aliases, 0, i, bi)
1379 tree al = referenced_var (i);
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;
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;
1394 if (flags & opf_def)
1395 append_vdef (al);
1396 else
1397 append_vuse (al);
1398 none_added = false;
1401 if (flags & opf_def)
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.
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);
1419 else
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);
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. */
1438 static void
1439 add_stmt_operand (tree *var_p, gimple stmt, int flags)
1441 tree var, sym;
1442 var_ann_t v_ann;
1444 gcc_assert (SSA_VAR_P (*var_p));
1446 var = *var_p;
1447 sym = (TREE_CODE (var) == SSA_NAME ? SSA_NAME_VAR (var) : var);
1448 v_ann = var_ann (sym);
1450 /* Mark statements with volatile operands. */
1451 if (TREE_THIS_VOLATILE (sym))
1452 gimple_set_has_volatile_ops (stmt, true);
1454 if (is_gimple_reg (sym))
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);
1462 else
1463 add_virtual_operand (var, stmt, flags, NULL_TREE, 0, -1, false);
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. */
1470 static void
1471 get_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)
1475 tree ptr = *addr;
1477 /* Mark the statement as having memory operands. */
1478 gimple_set_references_memory (stmt, true);
1480 if (SSA_VAR_P (ptr))
1482 struct ptr_info_def *pi = NULL;
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)
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);
1493 else
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;
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))
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);
1518 if (TREE_CODE (ptr) == SSA_NAME)
1519 ptr = SSA_NAME_VAR (ptr);
1520 v_ann = var_ann (ptr);
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)
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))
1532 if (flags & opf_def)
1533 append_vdef (v_ann->symbol_mem_tag);
1534 else
1535 append_vuse (v_ann->symbol_mem_tag);
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);
1546 else if (TREE_CODE (ptr) == INTEGER_CST)
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;
1554 else
1556 /* Ok, this isn't even is_gimple_min_invariant. Something's broke. */
1557 gcc_unreachable ();
1560 /* If requested, add a USE operand for the base pointer. */
1561 if (recurse_on_base)
1562 get_expr_operands (stmt, addr, opf_use);
1566 /* A subroutine of get_expr_operands to handle INDIRECT_REF,
1567 ALIGN_INDIRECT_REF and MISALIGNED_INDIRECT_REF.
1569 STMT is the statement being processed, EXPR is the INDIRECT_REF
1570 that got us here.
1572 FLAGS is as in get_expr_operands.
1574 FULL_REF contains the full pointer dereference expression, if we
1575 have it, or NULL otherwise.
1577 OFFSET and SIZE are the location of the access inside the
1578 dereferenced pointer, if known.
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. */
1584 static void
1585 get_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)
1589 tree *pptr = &TREE_OPERAND (expr, 0);
1591 if (TREE_THIS_VOLATILE (expr))
1592 gimple_set_has_volatile_ops (stmt, true);
1594 get_addr_dereference_operands (stmt, pptr, flags, full_ref, offset, size,
1595 recurse_on_base);
1599 /* A subroutine of get_expr_operands to handle TARGET_MEM_REF. */
1601 static void
1602 get_tmr_operands (gimple stmt, tree expr, int flags)
1604 tree tag;
1606 /* Mark the statement as having memory operands. */
1607 gimple_set_references_memory (stmt, true);
1609 /* First record the real operands. */
1610 get_expr_operands (stmt, &TMR_BASE (expr), opf_use);
1611 get_expr_operands (stmt, &TMR_INDEX (expr), opf_use);
1613 if (TMR_SYMBOL (expr))
1614 gimple_add_to_addresses_taken (stmt, TMR_SYMBOL (expr));
1616 tag = TMR_TAG (expr);
1617 if (!tag)
1619 /* Something weird, so ensure that we will be careful. */
1620 gimple_set_has_volatile_ops (stmt, true);
1621 return;
1623 if (!MTAG_P (tag))
1625 get_expr_operands (stmt, &tag, flags);
1626 return;
1629 add_virtual_operand (tag, stmt, flags, expr, 0, -1, false);
1633 /* Add clobbering definitions for .GLOBAL_VAR or for each of the call
1634 clobbered variables in the function. */
1636 static void
1637 add_call_clobber_ops (gimple stmt, tree callee ATTRIBUTE_UNUSED)
1639 unsigned u;
1640 bitmap_iterator bi;
1641 bitmap not_read_b, not_written_b;
1643 gcc_assert (!(gimple_call_flags (stmt) & (ECF_PURE | ECF_CONST)));
1645 /* If we created .GLOBAL_VAR earlier, just use it. */
1646 if (gimple_global_var (cfun))
1648 tree var = gimple_global_var (cfun);
1649 add_virtual_operand (var, stmt, opf_def, NULL, 0, -1, true);
1650 return;
1653 /* Get info for local and module level statics. There is a bit
1654 set for each static if the call being processed does not read
1655 or write that variable. */
1656 not_read_b = callee ? ipa_reference_get_not_read_global (cgraph_node (callee)) : NULL;
1657 not_written_b = callee ? ipa_reference_get_not_written_global (cgraph_node (callee)) : NULL;
1659 /* Add a VDEF operand for every call clobbered variable. */
1660 EXECUTE_IF_SET_IN_BITMAP (gimple_call_clobbered_vars (cfun), 0, u, bi)
1662 tree var = referenced_var_lookup (u);
1663 tree real_var = var;
1664 bool not_read;
1665 bool not_written;
1667 not_read = not_read_b
1668 ? bitmap_bit_p (not_read_b, DECL_UID (real_var))
1669 : false;
1671 not_written = not_written_b
1672 ? bitmap_bit_p (not_written_b, DECL_UID (real_var))
1673 : false;
1674 gcc_assert (!unmodifiable_var_p (var));
1676 clobber_stats.clobbered_vars++;
1678 /* See if this variable is really clobbered by this function. */
1680 if (not_written)
1682 clobber_stats.static_write_clobbers_avoided++;
1683 if (!not_read)
1684 add_virtual_operand (var, stmt, opf_use, NULL, 0, -1, true);
1685 else
1686 clobber_stats.static_read_clobbers_avoided++;
1688 else
1689 add_virtual_operand (var, stmt, opf_def, NULL, 0, -1, true);
1694 /* Add VUSE operands for .GLOBAL_VAR or all call clobbered variables in the
1695 function. */
1697 static void
1698 add_call_read_ops (gimple stmt, tree callee ATTRIBUTE_UNUSED)
1700 unsigned u;
1701 bitmap_iterator bi;
1702 bitmap not_read_b;
1704 /* Const functions do not reference memory. */
1705 if (gimple_call_flags (stmt) & ECF_CONST)
1706 return;
1708 not_read_b = callee ? ipa_reference_get_not_read_global (cgraph_node (callee)) : NULL;
1710 /* For pure functions we compute non-escaped uses separately. */
1711 if (gimple_call_flags (stmt) & ECF_PURE)
1712 EXECUTE_IF_SET_IN_BITMAP (gimple_call_used_vars (cfun), 0, u, bi)
1714 tree var = referenced_var_lookup (u);
1715 tree real_var = var;
1716 bool not_read;
1718 if (unmodifiable_var_p (var))
1719 continue;
1721 not_read = not_read_b
1722 ? bitmap_bit_p (not_read_b, DECL_UID (real_var))
1723 : false;
1725 clobber_stats.readonly_clobbers++;
1727 /* See if this variable is really used by this function. */
1728 if (!not_read)
1729 add_virtual_operand (var, stmt, opf_use, NULL, 0, -1, true);
1730 else
1731 clobber_stats.static_readonly_clobbers_avoided++;
1734 /* Add a VUSE for .GLOBAL_VAR if it has been created. See
1735 add_referenced_var for the heuristic used to decide whether to
1736 create .GLOBAL_VAR. */
1737 if (gimple_global_var (cfun))
1739 tree var = gimple_global_var (cfun);
1740 add_virtual_operand (var, stmt, opf_use, NULL, 0, -1, true);
1741 return;
1744 /* Add a VUSE for each call-clobbered variable. */
1745 EXECUTE_IF_SET_IN_BITMAP (gimple_call_clobbered_vars (cfun), 0, u, bi)
1747 tree var = referenced_var (u);
1748 tree real_var = var;
1749 bool not_read;
1751 clobber_stats.readonly_clobbers++;
1753 not_read = not_read_b ? bitmap_bit_p (not_read_b, DECL_UID (real_var))
1754 : false;
1756 if (not_read)
1758 clobber_stats.static_readonly_clobbers_avoided++;
1759 continue;
1762 add_virtual_operand (var, stmt, opf_use, NULL, 0, -1, true);
1767 /* If STMT is a call that may clobber globals and other symbols that
1768 escape, add them to the VDEF/VUSE lists for it. */
1770 static void
1771 maybe_add_call_clobbered_vops (gimple stmt)
1773 int call_flags = gimple_call_flags (stmt);
1775 /* Mark the statement as having memory operands. */
1776 gimple_set_references_memory (stmt, true);
1778 /* If aliases have been computed already, add VDEF or VUSE
1779 operands for all the symbols that have been found to be
1780 call-clobbered. */
1781 if (gimple_aliases_computed_p (cfun) && !(call_flags & ECF_NOVOPS))
1783 /* A 'pure' or a 'const' function never call-clobbers anything.
1784 A 'noreturn' function might, but since we don't return anyway
1785 there is no point in recording that. */
1786 if (!(call_flags & (ECF_PURE | ECF_CONST | ECF_NORETURN)))
1787 add_call_clobber_ops (stmt, gimple_call_fndecl (stmt));
1788 else if (!(call_flags & ECF_CONST))
1789 add_call_read_ops (stmt, gimple_call_fndecl (stmt));
1794 /* Scan operands in the ASM_EXPR stmt referred to in INFO. */
1796 static void
1797 get_asm_expr_operands (gimple stmt)
1799 size_t i, noutputs;
1800 const char **oconstraints;
1801 const char *constraint;
1802 bool allows_mem, allows_reg, is_inout;
1804 noutputs = gimple_asm_noutputs (stmt);
1805 oconstraints = (const char **) alloca ((noutputs) * sizeof (const char *));
1807 /* Gather all output operands. */
1808 for (i = 0; i < gimple_asm_noutputs (stmt); i++)
1810 tree link = gimple_asm_output_op (stmt, i);
1811 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
1812 oconstraints[i] = constraint;
1813 parse_output_constraint (&constraint, i, 0, 0, &allows_mem,
1814 &allows_reg, &is_inout);
1816 /* This should have been split in gimplify_asm_expr. */
1817 gcc_assert (!allows_reg || !is_inout);
1819 /* Memory operands are addressable. Note that STMT needs the
1820 address of this operand. */
1821 if (!allows_reg && allows_mem)
1823 tree t = get_base_address (TREE_VALUE (link));
1824 if (t && DECL_P (t))
1825 gimple_add_to_addresses_taken (stmt, t);
1828 get_expr_operands (stmt, &TREE_VALUE (link), opf_def);
1831 /* Gather all input operands. */
1832 for (i = 0; i < gimple_asm_ninputs (stmt); i++)
1834 tree link = gimple_asm_input_op (stmt, i);
1835 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
1836 parse_input_constraint (&constraint, 0, 0, noutputs, 0, oconstraints,
1837 &allows_mem, &allows_reg);
1839 /* Memory operands are addressable. Note that STMT needs the
1840 address of this operand. */
1841 if (!allows_reg && allows_mem)
1843 tree t = get_base_address (TREE_VALUE (link));
1844 if (t && DECL_P (t))
1845 gimple_add_to_addresses_taken (stmt, t);
1848 get_expr_operands (stmt, &TREE_VALUE (link), 0);
1851 /* Clobber all memory and addressable symbols for asm ("" : : : "memory"); */
1852 for (i = 0; i < gimple_asm_nclobbers (stmt); i++)
1854 tree link = gimple_asm_clobber_op (stmt, i);
1855 if (strcmp (TREE_STRING_POINTER (TREE_VALUE (link)), "memory") == 0)
1857 unsigned i;
1858 bitmap_iterator bi;
1860 /* Mark the statement as having memory operands. */
1861 gimple_set_references_memory (stmt, true);
1863 EXECUTE_IF_SET_IN_BITMAP (gimple_call_clobbered_vars (cfun), 0, i, bi)
1865 tree var = referenced_var (i);
1866 add_stmt_operand (&var, stmt, opf_def | opf_implicit);
1869 EXECUTE_IF_SET_IN_BITMAP (gimple_addressable_vars (cfun), 0, i, bi)
1871 tree var = referenced_var (i);
1872 add_stmt_operand (&var, stmt, opf_def | opf_implicit);
1874 break;
1880 /* Recursively scan the expression pointed to by EXPR_P in statement
1881 STMT. FLAGS is one of the OPF_* constants modifying how to
1882 interpret the operands found. */
1884 static void
1885 get_expr_operands (gimple stmt, tree *expr_p, int flags)
1887 enum tree_code code;
1888 enum tree_code_class codeclass;
1889 tree expr = *expr_p;
1891 if (expr == NULL)
1892 return;
1894 code = TREE_CODE (expr);
1895 codeclass = TREE_CODE_CLASS (code);
1897 switch (code)
1899 case ADDR_EXPR:
1900 /* Taking the address of a variable does not represent a
1901 reference to it, but the fact that the statement takes its
1902 address will be of interest to some passes (e.g. alias
1903 resolution). */
1904 gimple_add_to_addresses_taken (stmt, TREE_OPERAND (expr, 0));
1906 /* If the address is invariant, there may be no interesting
1907 variable references inside. */
1908 if (is_gimple_min_invariant (expr))
1909 return;
1911 /* Otherwise, there may be variables referenced inside but there
1912 should be no VUSEs created, since the referenced objects are
1913 not really accessed. The only operands that we should find
1914 here are ARRAY_REF indices which will always be real operands
1915 (GIMPLE does not allow non-registers as array indices). */
1916 flags |= opf_no_vops;
1917 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
1918 return;
1920 case SSA_NAME:
1921 case SYMBOL_MEMORY_TAG:
1922 case NAME_MEMORY_TAG:
1923 add_stmt_operand (expr_p, stmt, flags);
1924 return;
1926 case VAR_DECL:
1927 case PARM_DECL:
1928 case RESULT_DECL:
1929 add_stmt_operand (expr_p, stmt, flags);
1930 return;
1932 case MISALIGNED_INDIRECT_REF:
1933 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), flags);
1934 /* fall through */
1936 case ALIGN_INDIRECT_REF:
1937 case INDIRECT_REF:
1938 get_indirect_ref_operands (stmt, expr, flags, expr, 0, -1, true);
1939 return;
1941 case TARGET_MEM_REF:
1942 get_tmr_operands (stmt, expr, flags);
1943 return;
1945 case ARRAY_REF:
1946 case ARRAY_RANGE_REF:
1947 case COMPONENT_REF:
1948 case REALPART_EXPR:
1949 case IMAGPART_EXPR:
1951 tree ref;
1952 HOST_WIDE_INT offset, size, maxsize;
1954 if (TREE_THIS_VOLATILE (expr))
1955 gimple_set_has_volatile_ops (stmt, true);
1957 ref = get_ref_base_and_extent (expr, &offset, &size, &maxsize);
1958 if (TREE_CODE (ref) == INDIRECT_REF)
1960 get_indirect_ref_operands (stmt, ref, flags, expr, offset,
1961 maxsize, false);
1962 flags |= opf_no_vops;
1965 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
1967 if (code == COMPONENT_REF)
1969 if (TREE_THIS_VOLATILE (TREE_OPERAND (expr, 1)))
1970 gimple_set_has_volatile_ops (stmt, true);
1971 get_expr_operands (stmt, &TREE_OPERAND (expr, 2), opf_use);
1973 else if (code == ARRAY_REF || code == ARRAY_RANGE_REF)
1975 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), opf_use);
1976 get_expr_operands (stmt, &TREE_OPERAND (expr, 2), opf_use);
1977 get_expr_operands (stmt, &TREE_OPERAND (expr, 3), opf_use);
1980 return;
1983 case WITH_SIZE_EXPR:
1984 /* WITH_SIZE_EXPR is a pass-through reference to its first argument,
1985 and an rvalue reference to its second argument. */
1986 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), opf_use);
1987 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
1988 return;
1990 case COND_EXPR:
1991 case VEC_COND_EXPR:
1992 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), opf_use);
1993 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), opf_use);
1994 get_expr_operands (stmt, &TREE_OPERAND (expr, 2), opf_use);
1995 return;
1997 case CONSTRUCTOR:
1999 /* General aggregate CONSTRUCTORs have been decomposed, but they
2000 are still in use as the COMPLEX_EXPR equivalent for vectors. */
2001 constructor_elt *ce;
2002 unsigned HOST_WIDE_INT idx;
2004 for (idx = 0;
2005 VEC_iterate (constructor_elt, CONSTRUCTOR_ELTS (expr), idx, ce);
2006 idx++)
2007 get_expr_operands (stmt, &ce->value, opf_use);
2009 return;
2012 case BIT_FIELD_REF:
2013 case TRUTH_NOT_EXPR:
2014 case VIEW_CONVERT_EXPR:
2015 do_unary:
2016 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2017 return;
2019 case TRUTH_AND_EXPR:
2020 case TRUTH_OR_EXPR:
2021 case TRUTH_XOR_EXPR:
2022 case COMPOUND_EXPR:
2023 case OBJ_TYPE_REF:
2024 case ASSERT_EXPR:
2025 do_binary:
2027 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2028 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), flags);
2029 return;
2032 case DOT_PROD_EXPR:
2033 case REALIGN_LOAD_EXPR:
2035 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2036 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), flags);
2037 get_expr_operands (stmt, &TREE_OPERAND (expr, 2), flags);
2038 return;
2041 case CHANGE_DYNAMIC_TYPE_EXPR:
2042 gcc_unreachable ();
2044 case FUNCTION_DECL:
2045 case LABEL_DECL:
2046 case CONST_DECL:
2047 case CASE_LABEL_EXPR:
2048 case FILTER_EXPR:
2049 case EXC_PTR_EXPR:
2050 /* Expressions that make no memory references. */
2051 return;
2053 default:
2054 if (codeclass == tcc_unary)
2055 goto do_unary;
2056 if (codeclass == tcc_binary || codeclass == tcc_comparison)
2057 goto do_binary;
2058 if (codeclass == tcc_constant || codeclass == tcc_type)
2059 return;
2062 /* If we get here, something has gone wrong. */
2063 #ifdef ENABLE_CHECKING
2064 fprintf (stderr, "unhandled expression in get_expr_operands():\n");
2065 debug_tree (expr);
2066 fputs ("\n", stderr);
2067 #endif
2068 gcc_unreachable ();
2072 /* Parse STMT looking for operands. When finished, the various
2073 build_* operand vectors will have potential operands in them. */
2075 static void
2076 parse_ssa_operands (gimple stmt)
2078 enum gimple_code code = gimple_code (stmt);
2080 if (code == GIMPLE_ASM)
2081 get_asm_expr_operands (stmt);
2082 else
2084 size_t i, start = 0;
2086 if (code == GIMPLE_ASSIGN || code == GIMPLE_CALL)
2088 get_expr_operands (stmt, gimple_op_ptr (stmt, 0), opf_def);
2089 start = 1;
2092 for (i = start; i < gimple_num_ops (stmt); i++)
2093 get_expr_operands (stmt, gimple_op_ptr (stmt, i), opf_use);
2095 /* Add call-clobbered operands, if needed. */
2096 if (code == GIMPLE_CALL)
2097 maybe_add_call_clobbered_vops (stmt);
2102 /* Create an operands cache for STMT. */
2104 static void
2105 build_ssa_operands (gimple stmt)
2107 /* Initially assume that the statement has no volatile operands and
2108 makes no memory references. */
2109 gimple_set_has_volatile_ops (stmt, false);
2110 gimple_set_references_memory (stmt, false);
2112 /* Just clear the bitmap so we don't end up reallocating it over and over. */
2113 if (gimple_addresses_taken (stmt))
2114 bitmap_clear (gimple_addresses_taken (stmt));
2116 start_ssa_stmt_operands ();
2117 parse_ssa_operands (stmt);
2118 operand_build_sort_virtual (build_vuses);
2119 operand_build_sort_virtual (build_vdefs);
2120 finalize_ssa_stmt_operands (stmt);
2122 /* For added safety, assume that statements with volatile operands
2123 also reference memory. */
2124 if (gimple_has_volatile_ops (stmt))
2125 gimple_set_references_memory (stmt, true);
2129 /* Releases the operands of STMT back to their freelists, and clears
2130 the stmt operand lists. */
2132 void
2133 free_stmt_operands (gimple stmt)
2135 def_optype_p defs = gimple_def_ops (stmt), last_def;
2136 use_optype_p uses = gimple_use_ops (stmt), last_use;
2137 voptype_p vuses = gimple_vuse_ops (stmt);
2138 voptype_p vdefs = gimple_vdef_ops (stmt), vdef, next_vdef;
2139 unsigned i;
2141 if (defs)
2143 for (last_def = defs; last_def->next; last_def = last_def->next)
2144 continue;
2145 last_def->next = gimple_ssa_operands (cfun)->free_defs;
2146 gimple_ssa_operands (cfun)->free_defs = defs;
2147 gimple_set_def_ops (stmt, NULL);
2150 if (uses)
2152 for (last_use = uses; last_use->next; last_use = last_use->next)
2153 delink_imm_use (USE_OP_PTR (last_use));
2154 delink_imm_use (USE_OP_PTR (last_use));
2155 last_use->next = gimple_ssa_operands (cfun)->free_uses;
2156 gimple_ssa_operands (cfun)->free_uses = uses;
2157 gimple_set_use_ops (stmt, NULL);
2160 if (vuses)
2162 for (i = 0; i < VUSE_NUM (vuses); i++)
2163 delink_imm_use (VUSE_OP_PTR (vuses, i));
2164 add_vop_to_freelist (vuses);
2165 gimple_set_vuse_ops (stmt, NULL);
2168 if (vdefs)
2170 for (vdef = vdefs; vdef; vdef = next_vdef)
2172 next_vdef = vdef->next;
2173 delink_imm_use (VDEF_OP_PTR (vdef, 0));
2174 add_vop_to_freelist (vdef);
2176 gimple_set_vdef_ops (stmt, NULL);
2179 if (gimple_has_ops (stmt))
2180 gimple_set_addresses_taken (stmt, NULL);
2182 if (gimple_has_mem_ops (stmt))
2184 gimple_set_stored_syms (stmt, NULL, &operands_bitmap_obstack);
2185 gimple_set_loaded_syms (stmt, NULL, &operands_bitmap_obstack);
2190 /* Get the operands of statement STMT. */
2192 void
2193 update_stmt_operands (gimple stmt)
2195 /* If update_stmt_operands is called before SSA is initialized, do
2196 nothing. */
2197 if (!ssa_operands_active ())
2198 return;
2200 timevar_push (TV_TREE_OPS);
2202 gcc_assert (gimple_modified_p (stmt));
2203 build_ssa_operands (stmt);
2204 gimple_set_modified (stmt, false);
2206 timevar_pop (TV_TREE_OPS);
2210 /* Copies virtual operands from SRC to DST. */
2212 void
2213 copy_virtual_operands (gimple dest, gimple src)
2215 unsigned int i, n;
2216 voptype_p src_vuses, dest_vuses;
2217 voptype_p src_vdefs, dest_vdefs;
2218 struct voptype_d vuse;
2219 struct voptype_d vdef;
2221 if (!gimple_has_mem_ops (src))
2222 return;
2224 gimple_set_vdef_ops (dest, NULL);
2225 gimple_set_vuse_ops (dest, NULL);
2227 gimple_set_stored_syms (dest, gimple_stored_syms (src),
2228 &operands_bitmap_obstack);
2229 gimple_set_loaded_syms (dest, gimple_loaded_syms (src),
2230 &operands_bitmap_obstack);
2232 /* Copy all the VUSE operators and corresponding operands. */
2233 dest_vuses = &vuse;
2234 for (src_vuses = gimple_vuse_ops (src);
2235 src_vuses;
2236 src_vuses = src_vuses->next)
2238 n = VUSE_NUM (src_vuses);
2239 dest_vuses = add_vuse_op (dest, NULL_TREE, n, dest_vuses);
2240 for (i = 0; i < n; i++)
2241 SET_USE (VUSE_OP_PTR (dest_vuses, i), VUSE_OP (src_vuses, i));
2243 if (gimple_vuse_ops (dest) == NULL)
2244 gimple_set_vuse_ops (dest, vuse.next);
2247 /* Copy all the VDEF operators and corresponding operands. */
2248 dest_vdefs = &vdef;
2249 for (src_vdefs = gimple_vdef_ops (src);
2250 src_vdefs;
2251 src_vdefs = src_vdefs->next)
2253 n = VUSE_NUM (src_vdefs);
2254 dest_vdefs = add_vdef_op (dest, NULL_TREE, n, dest_vdefs);
2255 VDEF_RESULT (dest_vdefs) = VDEF_RESULT (src_vdefs);
2256 for (i = 0; i < n; i++)
2257 SET_USE (VUSE_OP_PTR (dest_vdefs, i), VUSE_OP (src_vdefs, i));
2259 if (gimple_vdef_ops (dest) == NULL)
2260 gimple_set_vdef_ops (dest, vdef.next);
2265 /* Specifically for use in DOM's expression analysis. Given a store, we
2266 create an artificial stmt which looks like a load from the store, this can
2267 be used to eliminate redundant loads. OLD_OPS are the operands from the
2268 store stmt, and NEW_STMT is the new load which represents a load of the
2269 values stored. If DELINK_IMM_USES_P is specified, the immediate
2270 uses of this stmt will be de-linked. */
2272 void
2273 create_ssa_artificial_load_stmt (gimple new_stmt, gimple old_stmt,
2274 bool delink_imm_uses_p)
2276 tree op;
2277 ssa_op_iter iter;
2278 use_operand_p use_p;
2279 unsigned i;
2281 gimple_set_modified (new_stmt, false);
2283 /* Process NEW_STMT looking for operands. */
2284 start_ssa_stmt_operands ();
2285 parse_ssa_operands (new_stmt);
2287 for (i = 0; VEC_iterate (tree, build_vuses, i, op); i++)
2288 if (TREE_CODE (op) != SSA_NAME)
2289 var_ann (op)->in_vuse_list = false;
2291 for (i = 0; VEC_iterate (tree, build_vdefs, i, op); i++)
2292 if (TREE_CODE (op) != SSA_NAME)
2293 var_ann (op)->in_vdef_list = false;
2295 /* Remove any virtual operands that were found. */
2296 VEC_truncate (tree, build_vdefs, 0);
2297 VEC_truncate (tree, build_vuses, 0);
2299 /* Clear the loads and stores bitmaps. */
2300 bitmap_clear (build_loads);
2301 bitmap_clear (build_stores);
2303 /* For each VDEF on the original statement, we want to create a
2304 VUSE of the VDEF result operand on the new statement. */
2305 FOR_EACH_SSA_TREE_OPERAND (op, old_stmt, iter, SSA_OP_VDEF)
2306 append_vuse (op);
2308 finalize_ssa_stmt_operands (new_stmt);
2310 /* All uses in this fake stmt must not be in the immediate use lists. */
2311 if (delink_imm_uses_p)
2312 FOR_EACH_SSA_USE_OPERAND (use_p, new_stmt, iter, SSA_OP_ALL_USES)
2313 delink_imm_use (use_p);
2317 /* Swap operands EXP0 and EXP1 in statement STMT. No attempt is done
2318 to test the validity of the swap operation. */
2320 void
2321 swap_tree_operands (gimple stmt, tree *exp0, tree *exp1)
2323 tree op0, op1;
2324 op0 = *exp0;
2325 op1 = *exp1;
2327 /* If the operand cache is active, attempt to preserve the relative
2328 positions of these two operands in their respective immediate use
2329 lists. */
2330 if (ssa_operands_active () && op0 != op1)
2332 use_optype_p use0, use1, ptr;
2333 use0 = use1 = NULL;
2335 /* Find the 2 operands in the cache, if they are there. */
2336 for (ptr = gimple_use_ops (stmt); ptr; ptr = ptr->next)
2337 if (USE_OP_PTR (ptr)->use == exp0)
2339 use0 = ptr;
2340 break;
2343 for (ptr = gimple_use_ops (stmt); ptr; ptr = ptr->next)
2344 if (USE_OP_PTR (ptr)->use == exp1)
2346 use1 = ptr;
2347 break;
2350 /* If both uses don't have operand entries, there isn't much we can do
2351 at this point. Presumably we don't need to worry about it. */
2352 if (use0 && use1)
2354 tree *tmp = USE_OP_PTR (use1)->use;
2355 USE_OP_PTR (use1)->use = USE_OP_PTR (use0)->use;
2356 USE_OP_PTR (use0)->use = tmp;
2360 /* Now swap the data. */
2361 *exp0 = op1;
2362 *exp1 = op0;
2365 /* Add the base address of REF to SET. */
2367 void
2368 add_to_addressable_set (tree ref, bitmap *set)
2370 tree var;
2372 /* Note that it is *NOT OKAY* to use the target of a COMPONENT_REF
2373 as the only thing we take the address of. If VAR is a structure,
2374 taking the address of a field means that the whole structure may
2375 be referenced using pointer arithmetic. See PR 21407 and the
2376 ensuing mailing list discussion. */
2377 var = get_base_address (ref);
2378 if (var && SSA_VAR_P (var))
2380 if (*set == NULL)
2381 *set = BITMAP_ALLOC (&operands_bitmap_obstack);
2383 bitmap_set_bit (*set, DECL_UID (var));
2384 TREE_ADDRESSABLE (var) = 1;
2389 /* Add the base address of REF to the set of addresses taken by STMT.
2390 REF may be a single variable whose address has been taken or any
2391 other valid GIMPLE memory reference (structure reference, array,
2392 etc). If the base address of REF is a decl that has sub-variables,
2393 also add all of its sub-variables. */
2395 void
2396 gimple_add_to_addresses_taken (gimple stmt, tree ref)
2398 gcc_assert (gimple_has_ops (stmt));
2399 add_to_addressable_set (ref, gimple_addresses_taken_ptr (stmt));
2403 /* Scan the immediate_use list for VAR making sure its linked properly.
2404 Return TRUE if there is a problem and emit an error message to F. */
2406 bool
2407 verify_imm_links (FILE *f, tree var)
2409 use_operand_p ptr, prev, list;
2410 int count;
2412 gcc_assert (TREE_CODE (var) == SSA_NAME);
2414 list = &(SSA_NAME_IMM_USE_NODE (var));
2415 gcc_assert (list->use == NULL);
2417 if (list->prev == NULL)
2419 gcc_assert (list->next == NULL);
2420 return false;
2423 prev = list;
2424 count = 0;
2425 for (ptr = list->next; ptr != list; )
2427 if (prev != ptr->prev)
2428 goto error;
2430 if (ptr->use == NULL)
2431 goto error; /* 2 roots, or SAFE guard node. */
2432 else if (*(ptr->use) != var)
2433 goto error;
2435 prev = ptr;
2436 ptr = ptr->next;
2438 /* Avoid infinite loops. 50,000,000 uses probably indicates a
2439 problem. */
2440 if (count++ > 50000000)
2441 goto error;
2444 /* Verify list in the other direction. */
2445 prev = list;
2446 for (ptr = list->prev; ptr != list; )
2448 if (prev != ptr->next)
2449 goto error;
2450 prev = ptr;
2451 ptr = ptr->prev;
2452 if (count-- < 0)
2453 goto error;
2456 if (count != 0)
2457 goto error;
2459 return false;
2461 error:
2462 if (ptr->loc.stmt && gimple_modified_p (ptr->loc.stmt))
2464 fprintf (f, " STMT MODIFIED. - <%p> ", (void *)ptr->loc.stmt);
2465 print_gimple_stmt (f, ptr->loc.stmt, 0, TDF_SLIM);
2467 fprintf (f, " IMM ERROR : (use_p : tree - %p:%p)", (void *)ptr,
2468 (void *)ptr->use);
2469 print_generic_expr (f, USE_FROM_PTR (ptr), TDF_SLIM);
2470 fprintf(f, "\n");
2471 return true;
2475 /* Dump all the immediate uses to FILE. */
2477 void
2478 dump_immediate_uses_for (FILE *file, tree var)
2480 imm_use_iterator iter;
2481 use_operand_p use_p;
2483 gcc_assert (var && TREE_CODE (var) == SSA_NAME);
2485 print_generic_expr (file, var, TDF_SLIM);
2486 fprintf (file, " : -->");
2487 if (has_zero_uses (var))
2488 fprintf (file, " no uses.\n");
2489 else
2490 if (has_single_use (var))
2491 fprintf (file, " single use.\n");
2492 else
2493 fprintf (file, "%d uses.\n", num_imm_uses (var));
2495 FOR_EACH_IMM_USE_FAST (use_p, iter, var)
2497 if (use_p->loc.stmt == NULL && use_p->use == NULL)
2498 fprintf (file, "***end of stmt iterator marker***\n");
2499 else
2500 if (!is_gimple_reg (USE_FROM_PTR (use_p)))
2501 print_gimple_stmt (file, USE_STMT (use_p), 0, TDF_VOPS|TDF_MEMSYMS);
2502 else
2503 print_gimple_stmt (file, USE_STMT (use_p), 0, TDF_SLIM);
2505 fprintf(file, "\n");
2509 /* Dump all the immediate uses to FILE. */
2511 void
2512 dump_immediate_uses (FILE *file)
2514 tree var;
2515 unsigned int x;
2517 fprintf (file, "Immediate_uses: \n\n");
2518 for (x = 1; x < num_ssa_names; x++)
2520 var = ssa_name(x);
2521 if (!var)
2522 continue;
2523 dump_immediate_uses_for (file, var);
2528 /* Dump def-use edges on stderr. */
2530 void
2531 debug_immediate_uses (void)
2533 dump_immediate_uses (stderr);
2537 /* Dump def-use edges on stderr. */
2539 void
2540 debug_immediate_uses_for (tree var)
2542 dump_immediate_uses_for (stderr, var);
2546 /* Create a new change buffer for the statement pointed by STMT_P and
2547 push the buffer into SCB_STACK. Each change buffer
2548 records state information needed to determine what changed in the
2549 statement. Mainly, this keeps track of symbols that may need to be
2550 put into SSA form, SSA name replacements and other information
2551 needed to keep the SSA form up to date. */
2553 void
2554 push_stmt_changes (gimple *stmt_p)
2556 gimple stmt;
2557 scb_t buf;
2559 stmt = *stmt_p;
2561 /* It makes no sense to keep track of PHI nodes. */
2562 if (gimple_code (stmt) == GIMPLE_PHI)
2563 return;
2565 buf = XNEW (struct scb_d);
2566 memset (buf, 0, sizeof *buf);
2568 buf->stmt_p = stmt_p;
2570 if (gimple_references_memory_p (stmt))
2572 tree op;
2573 ssa_op_iter i;
2575 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_VUSE)
2577 tree sym = TREE_CODE (op) == SSA_NAME ? SSA_NAME_VAR (op) : op;
2578 if (buf->loads == NULL)
2579 buf->loads = BITMAP_ALLOC (NULL);
2580 bitmap_set_bit (buf->loads, DECL_UID (sym));
2583 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_VDEF)
2585 tree sym = TREE_CODE (op) == SSA_NAME ? SSA_NAME_VAR (op) : op;
2586 if (buf->stores == NULL)
2587 buf->stores = BITMAP_ALLOC (NULL);
2588 bitmap_set_bit (buf->stores, DECL_UID (sym));
2592 VEC_safe_push (scb_t, heap, scb_stack, buf);
2596 /* Given two sets S1 and S2, mark the symbols that differ in S1 and S2
2597 for renaming. The set to mark for renaming is (S1 & ~S2) | (S2 & ~S1). */
2599 static void
2600 mark_difference_for_renaming (bitmap s1, bitmap s2)
2602 if (s1 == NULL && s2 == NULL)
2603 return;
2605 if (s1 && s2 == NULL)
2606 mark_set_for_renaming (s1);
2607 else if (s1 == NULL && s2)
2608 mark_set_for_renaming (s2);
2609 else if (!bitmap_equal_p (s1, s2))
2611 bitmap t1 = BITMAP_ALLOC (NULL);
2612 bitmap_xor (t1, s1, s2);
2613 mark_set_for_renaming (t1);
2614 BITMAP_FREE (t1);
2619 /* Pop the top SCB from SCB_STACK and act on the differences between
2620 what was recorded by push_stmt_changes and the current state of
2621 the statement. */
2623 void
2624 pop_stmt_changes (gimple *stmt_p)
2626 tree op;
2627 gimple stmt;
2628 ssa_op_iter iter;
2629 bitmap loads, stores;
2630 scb_t buf;
2632 stmt = *stmt_p;
2634 /* It makes no sense to keep track of PHI nodes. */
2635 if (gimple_code (stmt) == GIMPLE_PHI)
2636 return;
2638 buf = VEC_pop (scb_t, scb_stack);
2639 gcc_assert (stmt_p == buf->stmt_p);
2641 /* Force an operand re-scan on the statement and mark any newly
2642 exposed variables. */
2643 update_stmt (stmt);
2645 /* Determine whether any memory symbols need to be renamed. If the
2646 sets of loads and stores are different after the statement is
2647 modified, then the affected symbols need to be renamed.
2649 Note that it may be possible for the statement to not reference
2650 memory anymore, but we still need to act on the differences in
2651 the sets of symbols. */
2652 loads = stores = NULL;
2653 if (gimple_references_memory_p (stmt))
2655 tree op;
2656 ssa_op_iter i;
2658 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_VUSE)
2660 tree sym = TREE_CODE (op) == SSA_NAME ? SSA_NAME_VAR (op) : op;
2661 if (loads == NULL)
2662 loads = BITMAP_ALLOC (NULL);
2663 bitmap_set_bit (loads, DECL_UID (sym));
2666 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_VDEF)
2668 tree sym = TREE_CODE (op) == SSA_NAME ? SSA_NAME_VAR (op) : op;
2669 if (stores == NULL)
2670 stores = BITMAP_ALLOC (NULL);
2671 bitmap_set_bit (stores, DECL_UID (sym));
2675 /* If LOADS is different from BUF->LOADS, the affected
2676 symbols need to be marked for renaming. */
2677 mark_difference_for_renaming (loads, buf->loads);
2679 /* Similarly for STORES and BUF->STORES. */
2680 mark_difference_for_renaming (stores, buf->stores);
2682 /* Mark all the naked GIMPLE register operands for renaming. */
2683 FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_DEF|SSA_OP_USE)
2684 if (DECL_P (op))
2685 mark_sym_for_renaming (op);
2687 /* FIXME, need to add more finalizers here. Cleanup EH info,
2688 recompute invariants for address expressions, add
2689 SSA replacement mappings, etc. For instance, given
2690 testsuite/gcc.c-torture/compile/pr16808.c, we fold a statement of
2691 the form:
2693 # SMT.4_20 = VDEF <SMT.4_16>
2694 D.1576_11 = 1.0e+0;
2696 So, the VDEF will disappear, but instead of marking SMT.4 for
2697 renaming it would be far more efficient to establish a
2698 replacement mapping that would replace every reference of
2699 SMT.4_20 with SMT.4_16. */
2701 /* Free memory used by the buffer. */
2702 BITMAP_FREE (buf->loads);
2703 BITMAP_FREE (buf->stores);
2704 BITMAP_FREE (loads);
2705 BITMAP_FREE (stores);
2706 buf->stmt_p = NULL;
2707 free (buf);
2711 /* Discard the topmost change buffer from SCB_STACK. This is useful
2712 when the caller realized that it did not actually modified the
2713 statement. It avoids the expensive operand re-scan. */
2715 void
2716 discard_stmt_changes (gimple *stmt_p)
2718 scb_t buf;
2719 gimple stmt;
2721 /* It makes no sense to keep track of PHI nodes. */
2722 stmt = *stmt_p;
2723 if (gimple_code (stmt) == GIMPLE_PHI)
2724 return;
2726 buf = VEC_pop (scb_t, scb_stack);
2727 gcc_assert (stmt_p == buf->stmt_p);
2729 /* Free memory used by the buffer. */
2730 BITMAP_FREE (buf->loads);
2731 BITMAP_FREE (buf->stores);
2732 buf->stmt_p = NULL;
2733 free (buf);