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[official-gcc.git] / gcc / tree-ssa-operands.c
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1 /* SSA operands management for trees.
2 Copyright (C) 2003, 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3, or (at your option)
9 any later version.
11 GCC is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
20 #include "config.h"
21 #include "system.h"
22 #include "coretypes.h"
23 #include "tm.h"
24 #include "tree.h"
25 #include "flags.h"
26 #include "function.h"
27 #include "diagnostic.h"
28 #include "tree-flow.h"
29 #include "tree-inline.h"
30 #include "tree-pass.h"
31 #include "ggc.h"
32 #include "timevar.h"
33 #include "toplev.h"
34 #include "langhooks.h"
35 #include "ipa-reference.h"
37 /* This file contains the code required to manage the operands cache of the
38 SSA optimizer. For every stmt, we maintain an operand cache in the stmt
39 annotation. This cache contains operands that will be of interest to
40 optimizers and other passes wishing to manipulate the IL.
42 The operand type are broken up into REAL and VIRTUAL operands. The real
43 operands are represented as pointers into the stmt's operand tree. Thus
44 any manipulation of the real operands will be reflected in the actual tree.
45 Virtual operands are represented solely in the cache, although the base
46 variable for the SSA_NAME may, or may not occur in the stmt's tree.
47 Manipulation of the virtual operands will not be reflected in the stmt tree.
49 The routines in this file are concerned with creating this operand cache
50 from a stmt tree.
52 The operand tree is the parsed by the various get_* routines which look
53 through the stmt tree for the occurrence of operands which may be of
54 interest, and calls are made to the append_* routines whenever one is
55 found. There are 4 of these routines, each representing one of the
56 4 types of operands. Defs, Uses, Virtual Uses, and Virtual May Defs.
58 The append_* routines check for duplication, and simply keep a list of
59 unique objects for each operand type in the build_* extendable vectors.
61 Once the stmt tree is completely parsed, the finalize_ssa_operands()
62 routine is called, which proceeds to perform the finalization routine
63 on each of the 4 operand vectors which have been built up.
65 If the stmt had a previous operand cache, the finalization routines
66 attempt to match up the new operands with the old ones. If it's a perfect
67 match, the old vector is simply reused. If it isn't a perfect match, then
68 a new vector is created and the new operands are placed there. For
69 virtual operands, if the previous cache had SSA_NAME version of a
70 variable, and that same variable occurs in the same operands cache, then
71 the new cache vector will also get the same SSA_NAME.
73 i.e., if a stmt had a VUSE of 'a_5', and 'a' occurs in the new
74 operand vector for VUSE, then the new vector will also be modified
75 such that it contains 'a_5' rather than 'a'. */
78 /* Structure storing statistics on how many call clobbers we have, and
79 how many where avoided. */
81 static struct
83 /* Number of call-clobbered ops we attempt to add to calls in
84 add_call_clobbered_mem_symbols. */
85 unsigned int clobbered_vars;
87 /* Number of write-clobbers (VDEFs) avoided by using
88 not_written information. */
89 unsigned int static_write_clobbers_avoided;
91 /* Number of reads (VUSEs) avoided by using not_read information. */
92 unsigned int static_read_clobbers_avoided;
94 /* Number of write-clobbers avoided because the variable can't escape to
95 this call. */
96 unsigned int unescapable_clobbers_avoided;
98 /* Number of read-only uses we attempt to add to calls in
99 add_call_read_mem_symbols. */
100 unsigned int readonly_clobbers;
102 /* Number of read-only uses we avoid using not_read information. */
103 unsigned int static_readonly_clobbers_avoided;
104 } clobber_stats;
107 /* Flags to describe operand properties in helpers. */
109 /* By default, operands are loaded. */
110 #define opf_use 0
112 /* Operand is the target of an assignment expression or a
113 call-clobbered variable. */
114 #define opf_def (1 << 0)
116 /* No virtual operands should be created in the expression. This is used
117 when traversing ADDR_EXPR nodes which have different semantics than
118 other expressions. Inside an ADDR_EXPR node, the only operands that we
119 need to consider are indices into arrays. For instance, &a.b[i] should
120 generate a USE of 'i' but it should not generate a VUSE for 'a' nor a
121 VUSE for 'b'. */
122 #define opf_no_vops (1 << 1)
124 /* Operand is an implicit reference. This is used to distinguish
125 explicit assignments in the form of GIMPLE_MODIFY_STMT from
126 clobbering sites like function calls or ASM_EXPRs. */
127 #define opf_implicit (1 << 2)
129 /* Array for building all the def operands. */
130 static VEC(tree,heap) *build_defs;
132 /* Array for building all the use operands. */
133 static VEC(tree,heap) *build_uses;
135 /* Set for building all the VDEF operands. */
136 static VEC(tree,heap) *build_vdefs;
138 /* Set for building all the VUSE operands. */
139 static VEC(tree,heap) *build_vuses;
141 /* Bitmap obstack for our datastructures that needs to survive across
142 compilations of multiple functions. */
143 static bitmap_obstack operands_bitmap_obstack;
145 /* Set for building all the loaded symbols. */
146 static bitmap build_loads;
148 /* Set for building all the stored symbols. */
149 static bitmap build_stores;
151 static void get_expr_operands (tree, tree *, int);
153 /* Number of functions with initialized ssa_operands. */
154 static int n_initialized = 0;
156 /* Statement change buffer. Data structure used to record state
157 information for statements. This is used to determine what needs
158 to be done in order to update the SSA web after a statement is
159 modified by a pass. If STMT is a statement that has just been
160 created, or needs to be folded via fold_stmt, or anything that
161 changes its physical structure then the pass should:
163 1- Call push_stmt_changes (&stmt) to record the current state of
164 STMT before any modifications are made.
166 2- Make all appropriate modifications to the statement.
168 3- Call pop_stmt_changes (&stmt) to find new symbols that
169 need to be put in SSA form, SSA name mappings for names that
170 have disappeared, recompute invariantness for address
171 expressions, cleanup EH information, etc.
173 If it is possible to determine that the statement was not modified,
174 instead of calling pop_stmt_changes it is quicker to call
175 discard_stmt_changes to avoid the expensive and unnecessary operand
176 re-scan and change comparison. */
178 struct scb_d
180 /* Pointer to the statement being modified. */
181 tree *stmt_p;
183 /* If the statement references memory these are the sets of symbols
184 loaded and stored by the statement. */
185 bitmap loads;
186 bitmap stores;
189 typedef struct scb_d *scb_t;
190 DEF_VEC_P(scb_t);
191 DEF_VEC_ALLOC_P(scb_t,heap);
193 /* Stack of statement change buffers (SCB). Every call to
194 push_stmt_changes pushes a new buffer onto the stack. Calls to
195 pop_stmt_changes pop a buffer off of the stack and compute the set
196 of changes for the popped statement. */
197 static VEC(scb_t,heap) *scb_stack;
199 /* Return the DECL_UID of the base variable of T. */
201 static inline unsigned
202 get_name_decl (const_tree t)
204 if (TREE_CODE (t) != SSA_NAME)
205 return DECL_UID (t);
206 else
207 return DECL_UID (SSA_NAME_VAR (t));
211 /* Comparison function for qsort used in operand_build_sort_virtual. */
214 operand_build_cmp (const void *p, const void *q)
216 const_tree const e1 = *((const_tree const *)p);
217 const_tree const e2 = *((const_tree const *)q);
218 const unsigned int u1 = get_name_decl (e1);
219 const unsigned int u2 = get_name_decl (e2);
221 /* We want to sort in ascending order. They can never be equal. */
222 #ifdef ENABLE_CHECKING
223 gcc_assert (u1 != u2);
224 #endif
225 return (u1 > u2 ? 1 : -1);
229 /* Sort the virtual operands in LIST from lowest DECL_UID to highest. */
231 static inline void
232 operand_build_sort_virtual (VEC(tree,heap) *list)
234 int num = VEC_length (tree, list);
236 if (num < 2)
237 return;
239 if (num == 2)
241 if (get_name_decl (VEC_index (tree, list, 0))
242 > get_name_decl (VEC_index (tree, list, 1)))
244 /* Swap elements if in the wrong order. */
245 tree tmp = VEC_index (tree, list, 0);
246 VEC_replace (tree, list, 0, VEC_index (tree, list, 1));
247 VEC_replace (tree, list, 1, tmp);
249 return;
252 /* There are 3 or more elements, call qsort. */
253 qsort (VEC_address (tree, list),
254 VEC_length (tree, list),
255 sizeof (tree),
256 operand_build_cmp);
260 /* Return true if the SSA operands cache is active. */
262 bool
263 ssa_operands_active (void)
265 return cfun->gimple_df && gimple_ssa_operands (cfun)->ops_active;
269 /* VOPs are of variable sized, so the free list maps "free buckets" to the
270 following table:
271 bucket # operands
272 ------ ----------
276 15 16
277 16 17-24
278 17 25-32
279 18 31-40
281 29 121-128
282 Any VOPs larger than this are simply added to the largest bucket when they
283 are freed. */
286 /* Return the number of operands used in bucket BUCKET. */
288 static inline int
289 vop_free_bucket_size (int bucket)
291 #ifdef ENABLE_CHECKING
292 gcc_assert (bucket >= 0 && bucket < NUM_VOP_FREE_BUCKETS);
293 #endif
294 if (bucket < 16)
295 return bucket + 1;
296 return (bucket - 13) * 8;
300 /* For a vop of NUM operands, return the bucket NUM belongs to. If NUM is
301 beyond the end of the bucket table, return -1. */
303 static inline int
304 vop_free_bucket_index (int num)
306 gcc_assert (num > 0 && NUM_VOP_FREE_BUCKETS > 16);
308 /* Sizes 1 through 16 use buckets 0-15. */
309 if (num <= 16)
310 return num - 1;
311 /* Buckets 16 - NUM_VOP_FREE_BUCKETS represent 8 unit chunks. */
312 num = 14 + (num - 1) / 8;
313 if (num >= NUM_VOP_FREE_BUCKETS)
314 return -1;
315 else
316 return num;
320 /* Initialize the VOP free buckets. */
322 static inline void
323 init_vop_buckets (void)
325 int x;
327 for (x = 0; x < NUM_VOP_FREE_BUCKETS; x++)
328 gimple_ssa_operands (cfun)->vop_free_buckets[x] = NULL;
332 /* Add PTR to the appropriate VOP bucket. */
334 static inline void
335 add_vop_to_freelist (voptype_p ptr)
337 int bucket = vop_free_bucket_index (VUSE_VECT_NUM_ELEM (ptr->usev));
339 /* Too large, use the largest bucket so its not a complete throw away. */
340 if (bucket == -1)
341 bucket = NUM_VOP_FREE_BUCKETS - 1;
343 ptr->next = gimple_ssa_operands (cfun)->vop_free_buckets[bucket];
344 gimple_ssa_operands (cfun)->vop_free_buckets[bucket] = ptr;
348 /* These are the sizes of the operand memory buffer which gets allocated each
349 time more operands space is required. The final value is the amount that is
350 allocated every time after that. */
352 #define OP_SIZE_INIT 0
353 #define OP_SIZE_1 30
354 #define OP_SIZE_2 110
355 #define OP_SIZE_3 511
357 /* Initialize the operand cache routines. */
359 void
360 init_ssa_operands (void)
362 if (!n_initialized++)
364 build_defs = VEC_alloc (tree, heap, 5);
365 build_uses = VEC_alloc (tree, heap, 10);
366 build_vuses = VEC_alloc (tree, heap, 25);
367 build_vdefs = VEC_alloc (tree, heap, 25);
368 bitmap_obstack_initialize (&operands_bitmap_obstack);
369 build_loads = BITMAP_ALLOC (&operands_bitmap_obstack);
370 build_stores = BITMAP_ALLOC (&operands_bitmap_obstack);
371 scb_stack = VEC_alloc (scb_t, heap, 20);
374 gcc_assert (gimple_ssa_operands (cfun)->operand_memory == NULL);
375 gcc_assert (gimple_ssa_operands (cfun)->mpt_table == NULL);
376 gimple_ssa_operands (cfun)->operand_memory_index
377 = gimple_ssa_operands (cfun)->ssa_operand_mem_size;
378 gimple_ssa_operands (cfun)->ops_active = true;
379 memset (&clobber_stats, 0, sizeof (clobber_stats));
380 init_vop_buckets ();
381 gimple_ssa_operands (cfun)->ssa_operand_mem_size = OP_SIZE_INIT;
385 /* Dispose of anything required by the operand routines. */
387 void
388 fini_ssa_operands (void)
390 struct ssa_operand_memory_d *ptr;
391 unsigned ix;
392 tree mpt;
394 if (!--n_initialized)
396 VEC_free (tree, heap, build_defs);
397 VEC_free (tree, heap, build_uses);
398 VEC_free (tree, heap, build_vdefs);
399 VEC_free (tree, heap, build_vuses);
400 BITMAP_FREE (build_loads);
401 BITMAP_FREE (build_stores);
403 /* The change buffer stack had better be empty. */
404 gcc_assert (VEC_length (scb_t, scb_stack) == 0);
405 VEC_free (scb_t, heap, scb_stack);
406 scb_stack = NULL;
409 gimple_ssa_operands (cfun)->free_defs = NULL;
410 gimple_ssa_operands (cfun)->free_uses = NULL;
412 while ((ptr = gimple_ssa_operands (cfun)->operand_memory) != NULL)
414 gimple_ssa_operands (cfun)->operand_memory
415 = gimple_ssa_operands (cfun)->operand_memory->next;
416 ggc_free (ptr);
419 for (ix = 0;
420 VEC_iterate (tree, gimple_ssa_operands (cfun)->mpt_table, ix, mpt);
421 ix++)
423 if (mpt)
424 BITMAP_FREE (MPT_SYMBOLS (mpt));
427 VEC_free (tree, heap, gimple_ssa_operands (cfun)->mpt_table);
429 gimple_ssa_operands (cfun)->ops_active = false;
431 if (!n_initialized)
432 bitmap_obstack_release (&operands_bitmap_obstack);
433 if (dump_file && (dump_flags & TDF_STATS))
435 fprintf (dump_file, "Original clobbered vars: %d\n",
436 clobber_stats.clobbered_vars);
437 fprintf (dump_file, "Static write clobbers avoided: %d\n",
438 clobber_stats.static_write_clobbers_avoided);
439 fprintf (dump_file, "Static read clobbers avoided: %d\n",
440 clobber_stats.static_read_clobbers_avoided);
441 fprintf (dump_file, "Unescapable clobbers avoided: %d\n",
442 clobber_stats.unescapable_clobbers_avoided);
443 fprintf (dump_file, "Original read-only clobbers: %d\n",
444 clobber_stats.readonly_clobbers);
445 fprintf (dump_file, "Static read-only clobbers avoided: %d\n",
446 clobber_stats.static_readonly_clobbers_avoided);
451 /* Return memory for operands of SIZE chunks. */
453 static inline void *
454 ssa_operand_alloc (unsigned size)
456 char *ptr;
458 if (gimple_ssa_operands (cfun)->operand_memory_index + size
459 >= gimple_ssa_operands (cfun)->ssa_operand_mem_size)
461 struct ssa_operand_memory_d *ptr;
463 if (gimple_ssa_operands (cfun)->ssa_operand_mem_size == OP_SIZE_INIT)
464 gimple_ssa_operands (cfun)->ssa_operand_mem_size
465 = OP_SIZE_1 * sizeof (struct voptype_d);
466 else
467 if (gimple_ssa_operands (cfun)->ssa_operand_mem_size
468 == OP_SIZE_1 * sizeof (struct voptype_d))
469 gimple_ssa_operands (cfun)->ssa_operand_mem_size
470 = OP_SIZE_2 * sizeof (struct voptype_d);
471 else
472 gimple_ssa_operands (cfun)->ssa_operand_mem_size
473 = OP_SIZE_3 * sizeof (struct voptype_d);
475 /* Go right to the maximum size if the request is too large. */
476 if (size > gimple_ssa_operands (cfun)->ssa_operand_mem_size)
477 gimple_ssa_operands (cfun)->ssa_operand_mem_size
478 = OP_SIZE_3 * sizeof (struct voptype_d);
480 /* We can reliably trigger the case that we need arbitrary many
481 operands (see PR34093), so allocate a buffer just for this request. */
482 if (size > gimple_ssa_operands (cfun)->ssa_operand_mem_size)
483 gimple_ssa_operands (cfun)->ssa_operand_mem_size = size;
485 ptr = (struct ssa_operand_memory_d *)
486 ggc_alloc (sizeof (struct ssa_operand_memory_d)
487 + gimple_ssa_operands (cfun)->ssa_operand_mem_size - 1);
488 ptr->next = gimple_ssa_operands (cfun)->operand_memory;
489 gimple_ssa_operands (cfun)->operand_memory = ptr;
490 gimple_ssa_operands (cfun)->operand_memory_index = 0;
492 ptr = &(gimple_ssa_operands (cfun)->operand_memory
493 ->mem[gimple_ssa_operands (cfun)->operand_memory_index]);
494 gimple_ssa_operands (cfun)->operand_memory_index += size;
495 return ptr;
499 /* Allocate a DEF operand. */
501 static inline struct def_optype_d *
502 alloc_def (void)
504 struct def_optype_d *ret;
505 if (gimple_ssa_operands (cfun)->free_defs)
507 ret = gimple_ssa_operands (cfun)->free_defs;
508 gimple_ssa_operands (cfun)->free_defs
509 = gimple_ssa_operands (cfun)->free_defs->next;
511 else
512 ret = (struct def_optype_d *)
513 ssa_operand_alloc (sizeof (struct def_optype_d));
514 return ret;
518 /* Allocate a USE operand. */
520 static inline struct use_optype_d *
521 alloc_use (void)
523 struct use_optype_d *ret;
524 if (gimple_ssa_operands (cfun)->free_uses)
526 ret = gimple_ssa_operands (cfun)->free_uses;
527 gimple_ssa_operands (cfun)->free_uses
528 = gimple_ssa_operands (cfun)->free_uses->next;
530 else
531 ret = (struct use_optype_d *)
532 ssa_operand_alloc (sizeof (struct use_optype_d));
533 return ret;
537 /* Allocate a vop with NUM elements. */
539 static inline struct voptype_d *
540 alloc_vop (int num)
542 struct voptype_d *ret = NULL;
543 int alloc_size = 0;
545 int bucket = vop_free_bucket_index (num);
546 if (bucket != -1)
548 /* If there is a free operand, use it. */
549 if (gimple_ssa_operands (cfun)->vop_free_buckets[bucket] != NULL)
551 ret = gimple_ssa_operands (cfun)->vop_free_buckets[bucket];
552 gimple_ssa_operands (cfun)->vop_free_buckets[bucket] =
553 gimple_ssa_operands (cfun)->vop_free_buckets[bucket]->next;
555 else
556 alloc_size = vop_free_bucket_size(bucket);
558 else
559 alloc_size = num;
561 if (alloc_size > 0)
562 ret = (struct voptype_d *)ssa_operand_alloc (
563 sizeof (struct voptype_d) + (alloc_size - 1) * sizeof (vuse_element_t));
565 VUSE_VECT_NUM_ELEM (ret->usev) = num;
566 return ret;
570 /* This routine makes sure that PTR is in an immediate use list, and makes
571 sure the stmt pointer is set to the current stmt. */
573 static inline void
574 set_virtual_use_link (use_operand_p ptr, tree stmt)
576 /* fold_stmt may have changed the stmt pointers. */
577 if (ptr->stmt != stmt)
578 ptr->stmt = stmt;
580 /* If this use isn't in a list, add it to the correct list. */
581 if (!ptr->prev)
582 link_imm_use (ptr, *(ptr->use));
586 /* Adds OP to the list of defs after LAST. */
588 static inline def_optype_p
589 add_def_op (tree *op, def_optype_p last)
591 def_optype_p new_def;
593 new_def = alloc_def ();
594 DEF_OP_PTR (new_def) = op;
595 last->next = new_def;
596 new_def->next = NULL;
597 return new_def;
601 /* Adds OP to the list of uses of statement STMT after LAST. */
603 static inline use_optype_p
604 add_use_op (tree stmt, tree *op, use_optype_p last)
606 use_optype_p new_use;
608 new_use = alloc_use ();
609 USE_OP_PTR (new_use)->use = op;
610 link_imm_use_stmt (USE_OP_PTR (new_use), *op, stmt);
611 last->next = new_use;
612 new_use->next = NULL;
613 return new_use;
617 /* Return a virtual op pointer with NUM elements which are all
618 initialized to OP and are linked into the immediate uses for STMT.
619 The new vop is appended after PREV. */
621 static inline voptype_p
622 add_vop (tree stmt, tree op, int num, voptype_p prev)
624 voptype_p new_vop;
625 int x;
627 new_vop = alloc_vop (num);
628 for (x = 0; x < num; x++)
630 VUSE_OP_PTR (new_vop, x)->prev = NULL;
631 SET_VUSE_OP (new_vop, x, op);
632 VUSE_OP_PTR (new_vop, x)->use = &new_vop->usev.uses[x].use_var;
633 link_imm_use_stmt (VUSE_OP_PTR (new_vop, x),
634 new_vop->usev.uses[x].use_var, stmt);
637 if (prev)
638 prev->next = new_vop;
639 new_vop->next = NULL;
640 return new_vop;
644 /* Adds OP to the list of vuses of statement STMT after LAST, and moves
645 LAST to the new element. */
647 static inline voptype_p
648 add_vuse_op (tree stmt, tree op, int num, voptype_p last)
650 voptype_p new_vop = add_vop (stmt, op, num, last);
651 VDEF_RESULT (new_vop) = NULL_TREE;
652 return new_vop;
656 /* Adds OP to the list of vdefs of statement STMT after LAST, and moves
657 LAST to the new element. */
659 static inline voptype_p
660 add_vdef_op (tree stmt, tree op, int num, voptype_p last)
662 voptype_p new_vop = add_vop (stmt, op, num, last);
663 VDEF_RESULT (new_vop) = op;
664 return new_vop;
668 /* Takes elements from build_defs and turns them into def operands of STMT.
669 TODO -- Make build_defs VEC of tree *. */
671 static inline void
672 finalize_ssa_defs (tree stmt)
674 unsigned new_i;
675 struct def_optype_d new_list;
676 def_optype_p old_ops, last;
677 unsigned int num = VEC_length (tree, build_defs);
679 /* There should only be a single real definition per assignment. */
680 gcc_assert ((stmt && TREE_CODE (stmt) != GIMPLE_MODIFY_STMT) || num <= 1);
682 new_list.next = NULL;
683 last = &new_list;
685 old_ops = DEF_OPS (stmt);
687 new_i = 0;
689 /* Check for the common case of 1 def that hasn't changed. */
690 if (old_ops && old_ops->next == NULL && num == 1
691 && (tree *) VEC_index (tree, build_defs, 0) == DEF_OP_PTR (old_ops))
692 return;
694 /* If there is anything in the old list, free it. */
695 if (old_ops)
697 old_ops->next = gimple_ssa_operands (cfun)->free_defs;
698 gimple_ssa_operands (cfun)->free_defs = old_ops;
701 /* If there is anything remaining in the build_defs list, simply emit it. */
702 for ( ; new_i < num; new_i++)
703 last = add_def_op ((tree *) VEC_index (tree, build_defs, new_i), last);
705 /* Now set the stmt's operands. */
706 DEF_OPS (stmt) = new_list.next;
708 #ifdef ENABLE_CHECKING
710 def_optype_p ptr;
711 unsigned x = 0;
712 for (ptr = DEF_OPS (stmt); ptr; ptr = ptr->next)
713 x++;
715 gcc_assert (x == num);
717 #endif
721 /* Takes elements from build_uses and turns them into use operands of STMT.
722 TODO -- Make build_uses VEC of tree *. */
724 static inline void
725 finalize_ssa_uses (tree stmt)
727 unsigned new_i;
728 struct use_optype_d new_list;
729 use_optype_p old_ops, ptr, last;
731 #ifdef ENABLE_CHECKING
733 unsigned x;
734 unsigned num = VEC_length (tree, build_uses);
736 /* If the pointer to the operand is the statement itself, something is
737 wrong. It means that we are pointing to a local variable (the
738 initial call to update_stmt_operands does not pass a pointer to a
739 statement). */
740 for (x = 0; x < num; x++)
741 gcc_assert (*((tree *)VEC_index (tree, build_uses, x)) != stmt);
743 #endif
745 new_list.next = NULL;
746 last = &new_list;
748 old_ops = USE_OPS (stmt);
750 /* If there is anything in the old list, free it. */
751 if (old_ops)
753 for (ptr = old_ops; ptr; ptr = ptr->next)
754 delink_imm_use (USE_OP_PTR (ptr));
755 old_ops->next = gimple_ssa_operands (cfun)->free_uses;
756 gimple_ssa_operands (cfun)->free_uses = old_ops;
759 /* Now create nodes for all the new nodes. */
760 for (new_i = 0; new_i < VEC_length (tree, build_uses); new_i++)
761 last = add_use_op (stmt,
762 (tree *) VEC_index (tree, build_uses, new_i),
763 last);
765 /* Now set the stmt's operands. */
766 USE_OPS (stmt) = new_list.next;
768 #ifdef ENABLE_CHECKING
770 unsigned x = 0;
771 for (ptr = USE_OPS (stmt); ptr; ptr = ptr->next)
772 x++;
774 gcc_assert (x == VEC_length (tree, build_uses));
776 #endif
780 /* Takes elements from BUILD_VDEFS and turns them into vdef operands of
781 STMT. FIXME, for now VDEF operators should have a single operand
782 in their RHS. */
784 static inline void
785 finalize_ssa_vdefs (tree stmt)
787 unsigned new_i;
788 struct voptype_d new_list;
789 voptype_p old_ops, ptr, last;
790 stmt_ann_t ann = stmt_ann (stmt);
792 /* Set the symbols referenced by STMT. */
793 if (!bitmap_empty_p (build_stores))
795 if (ann->operands.stores == NULL)
796 ann->operands.stores = BITMAP_ALLOC (&operands_bitmap_obstack);
798 bitmap_copy (ann->operands.stores, build_stores);
800 else
801 BITMAP_FREE (ann->operands.stores);
803 /* If aliases have not been computed, do not instantiate a virtual
804 operator on STMT. Initially, we only compute the SSA form on
805 GIMPLE registers. The virtual SSA form is only computed after
806 alias analysis, so virtual operators will remain unrenamed and
807 the verifier will complain. However, alias analysis needs to
808 access symbol load/store information, so we need to compute
809 those. */
810 if (!gimple_aliases_computed_p (cfun))
811 return;
813 new_list.next = NULL;
814 last = &new_list;
816 old_ops = VDEF_OPS (stmt);
817 new_i = 0;
818 while (old_ops && new_i < VEC_length (tree, build_vdefs))
820 tree op = VEC_index (tree, build_vdefs, new_i);
821 unsigned new_uid = get_name_decl (op);
822 unsigned old_uid = get_name_decl (VDEF_RESULT (old_ops));
824 /* FIXME, for now each VDEF operator should have at most one
825 operand in their RHS. */
826 gcc_assert (VDEF_NUM (old_ops) == 1);
828 if (old_uid == new_uid)
830 /* If the symbols are the same, reuse the existing operand. */
831 last->next = old_ops;
832 last = old_ops;
833 old_ops = old_ops->next;
834 last->next = NULL;
835 set_virtual_use_link (VDEF_OP_PTR (last, 0), stmt);
836 new_i++;
838 else if (old_uid < new_uid)
840 /* If old is less than new, old goes to the free list. */
841 voptype_p next;
842 delink_imm_use (VDEF_OP_PTR (old_ops, 0));
843 next = old_ops->next;
844 add_vop_to_freelist (old_ops);
845 old_ops = next;
847 else
849 /* This is a new operand. */
850 last = add_vdef_op (stmt, op, 1, last);
851 new_i++;
855 /* If there is anything remaining in BUILD_VDEFS, simply emit it. */
856 for ( ; new_i < VEC_length (tree, build_vdefs); new_i++)
857 last = add_vdef_op (stmt, VEC_index (tree, build_vdefs, new_i), 1, last);
859 /* If there is anything in the old list, free it. */
860 if (old_ops)
862 for (ptr = old_ops; ptr; ptr = last)
864 last = ptr->next;
865 delink_imm_use (VDEF_OP_PTR (ptr, 0));
866 add_vop_to_freelist (ptr);
870 /* Now set STMT's operands. */
871 VDEF_OPS (stmt) = new_list.next;
873 #ifdef ENABLE_CHECKING
875 unsigned x = 0;
876 for (ptr = VDEF_OPS (stmt); ptr; ptr = ptr->next)
877 x++;
879 gcc_assert (x == VEC_length (tree, build_vdefs));
881 #endif
885 /* Takes elements from BUILD_VUSES and turns them into VUSE operands of
886 STMT. */
888 static inline void
889 finalize_ssa_vuse_ops (tree stmt)
891 unsigned new_i, old_i;
892 voptype_p old_ops, last;
893 VEC(tree,heap) *new_ops;
894 stmt_ann_t ann;
896 /* Set the symbols referenced by STMT. */
897 ann = stmt_ann (stmt);
898 if (!bitmap_empty_p (build_loads))
900 if (ann->operands.loads == NULL)
901 ann->operands.loads = BITMAP_ALLOC (&operands_bitmap_obstack);
903 bitmap_copy (ann->operands.loads, build_loads);
905 else
906 BITMAP_FREE (ann->operands.loads);
908 /* If aliases have not been computed, do not instantiate a virtual
909 operator on STMT. Initially, we only compute the SSA form on
910 GIMPLE registers. The virtual SSA form is only computed after
911 alias analysis, so virtual operators will remain unrenamed and
912 the verifier will complain. However, alias analysis needs to
913 access symbol load/store information, so we need to compute
914 those. */
915 if (!gimple_aliases_computed_p (cfun))
916 return;
918 /* STMT should have at most one VUSE operator. */
919 old_ops = VUSE_OPS (stmt);
920 gcc_assert (old_ops == NULL || old_ops->next == NULL);
922 new_ops = NULL;
923 new_i = old_i = 0;
924 while (old_ops
925 && old_i < VUSE_NUM (old_ops)
926 && new_i < VEC_length (tree, build_vuses))
928 tree new_op = VEC_index (tree, build_vuses, new_i);
929 tree old_op = VUSE_OP (old_ops, old_i);
930 unsigned new_uid = get_name_decl (new_op);
931 unsigned old_uid = get_name_decl (old_op);
933 if (old_uid == new_uid)
935 /* If the symbols are the same, reuse the existing operand. */
936 VEC_safe_push (tree, heap, new_ops, old_op);
937 new_i++;
938 old_i++;
940 else if (old_uid < new_uid)
942 /* If OLD_UID is less than NEW_UID, the old operand has
943 disappeared, skip to the next old operand. */
944 old_i++;
946 else
948 /* This is a new operand. */
949 VEC_safe_push (tree, heap, new_ops, new_op);
950 new_i++;
954 /* If there is anything remaining in the build_vuses list, simply emit it. */
955 for ( ; new_i < VEC_length (tree, build_vuses); new_i++)
956 VEC_safe_push (tree, heap, new_ops, VEC_index (tree, build_vuses, new_i));
958 /* If there is anything in the old list, free it. */
959 if (old_ops)
961 for (old_i = 0; old_i < VUSE_NUM (old_ops); old_i++)
962 delink_imm_use (VUSE_OP_PTR (old_ops, old_i));
963 add_vop_to_freelist (old_ops);
964 VUSE_OPS (stmt) = NULL;
967 /* If there are any operands, instantiate a VUSE operator for STMT. */
968 if (new_ops)
970 tree op;
971 unsigned i;
973 last = add_vuse_op (stmt, NULL, VEC_length (tree, new_ops), NULL);
975 for (i = 0; VEC_iterate (tree, new_ops, i, op); i++)
976 SET_USE (VUSE_OP_PTR (last, (int) i), op);
978 VUSE_OPS (stmt) = last;
979 VEC_free (tree, heap, new_ops);
982 #ifdef ENABLE_CHECKING
984 unsigned x;
986 if (VUSE_OPS (stmt))
988 gcc_assert (VUSE_OPS (stmt)->next == NULL);
989 x = VUSE_NUM (VUSE_OPS (stmt));
991 else
992 x = 0;
994 gcc_assert (x == VEC_length (tree, build_vuses));
996 #endif
999 /* Return a new VUSE operand vector for STMT. */
1001 static void
1002 finalize_ssa_vuses (tree stmt)
1004 unsigned num, num_vdefs;
1005 unsigned vuse_index;
1007 /* Remove superfluous VUSE operands. If the statement already has a
1008 VDEF operator for a variable 'a', then a VUSE for 'a' is not
1009 needed because VDEFs imply a VUSE of the variable. For instance,
1010 suppose that variable 'a' is pointed-to by p and q:
1012 # VUSE <a_2>
1013 # a_3 = VDEF <a_2>
1014 *p = *q;
1016 The VUSE <a_2> is superfluous because it is implied by the
1017 VDEF operator. */
1018 num = VEC_length (tree, build_vuses);
1019 num_vdefs = VEC_length (tree, build_vdefs);
1021 if (num > 0 && num_vdefs > 0)
1022 for (vuse_index = 0; vuse_index < VEC_length (tree, build_vuses); )
1024 tree vuse;
1025 vuse = VEC_index (tree, build_vuses, vuse_index);
1026 if (TREE_CODE (vuse) != SSA_NAME)
1028 var_ann_t ann = var_ann (vuse);
1029 ann->in_vuse_list = 0;
1030 if (ann->in_vdef_list)
1032 VEC_ordered_remove (tree, build_vuses, vuse_index);
1033 continue;
1036 vuse_index++;
1039 finalize_ssa_vuse_ops (stmt);
1043 /* Clear the in_list bits and empty the build array for VDEFs and
1044 VUSEs. */
1046 static inline void
1047 cleanup_build_arrays (void)
1049 unsigned i;
1050 tree t;
1052 for (i = 0; VEC_iterate (tree, build_vdefs, i, t); i++)
1053 if (TREE_CODE (t) != SSA_NAME)
1054 var_ann (t)->in_vdef_list = false;
1056 for (i = 0; VEC_iterate (tree, build_vuses, i, t); i++)
1057 if (TREE_CODE (t) != SSA_NAME)
1058 var_ann (t)->in_vuse_list = false;
1060 VEC_truncate (tree, build_vdefs, 0);
1061 VEC_truncate (tree, build_vuses, 0);
1062 VEC_truncate (tree, build_defs, 0);
1063 VEC_truncate (tree, build_uses, 0);
1064 bitmap_clear (build_loads);
1065 bitmap_clear (build_stores);
1069 /* Finalize all the build vectors, fill the new ones into INFO. */
1071 static inline void
1072 finalize_ssa_stmt_operands (tree stmt)
1074 finalize_ssa_defs (stmt);
1075 finalize_ssa_uses (stmt);
1076 finalize_ssa_vdefs (stmt);
1077 finalize_ssa_vuses (stmt);
1078 cleanup_build_arrays ();
1082 /* Start the process of building up operands vectors in INFO. */
1084 static inline void
1085 start_ssa_stmt_operands (void)
1087 gcc_assert (VEC_length (tree, build_defs) == 0);
1088 gcc_assert (VEC_length (tree, build_uses) == 0);
1089 gcc_assert (VEC_length (tree, build_vuses) == 0);
1090 gcc_assert (VEC_length (tree, build_vdefs) == 0);
1091 gcc_assert (bitmap_empty_p (build_loads));
1092 gcc_assert (bitmap_empty_p (build_stores));
1096 /* Add DEF_P to the list of pointers to operands. */
1098 static inline void
1099 append_def (tree *def_p)
1101 VEC_safe_push (tree, heap, build_defs, (tree) def_p);
1105 /* Add USE_P to the list of pointers to operands. */
1107 static inline void
1108 append_use (tree *use_p)
1110 VEC_safe_push (tree, heap, build_uses, (tree) use_p);
1114 /* Add VAR to the set of variables that require a VDEF operator. */
1116 static inline void
1117 append_vdef (tree var)
1119 tree sym;
1121 if (TREE_CODE (var) != SSA_NAME)
1123 tree mpt;
1124 var_ann_t ann;
1126 /* If VAR belongs to a memory partition, use it instead of VAR. */
1127 mpt = memory_partition (var);
1128 if (mpt)
1129 var = mpt;
1131 /* Don't allow duplicate entries. */
1132 ann = get_var_ann (var);
1133 if (ann->in_vdef_list)
1134 return;
1136 ann->in_vdef_list = true;
1137 sym = var;
1139 else
1140 sym = SSA_NAME_VAR (var);
1142 VEC_safe_push (tree, heap, build_vdefs, var);
1143 bitmap_set_bit (build_stores, DECL_UID (sym));
1147 /* Add VAR to the set of variables that require a VUSE operator. */
1149 static inline void
1150 append_vuse (tree var)
1152 tree sym;
1154 if (TREE_CODE (var) != SSA_NAME)
1156 tree mpt;
1157 var_ann_t ann;
1159 /* If VAR belongs to a memory partition, use it instead of VAR. */
1160 mpt = memory_partition (var);
1161 if (mpt)
1162 var = mpt;
1164 /* Don't allow duplicate entries. */
1165 ann = get_var_ann (var);
1166 if (ann->in_vuse_list)
1167 return;
1168 else if (ann->in_vdef_list)
1170 /* We don't want a vuse if we already have a vdef, but we must
1171 still put this in build_loads. */
1172 bitmap_set_bit (build_loads, DECL_UID (var));
1173 return;
1176 ann->in_vuse_list = true;
1177 sym = var;
1179 else
1180 sym = SSA_NAME_VAR (var);
1182 VEC_safe_push (tree, heap, build_vuses, var);
1183 bitmap_set_bit (build_loads, DECL_UID (sym));
1187 /* REF is a tree that contains the entire pointer dereference
1188 expression, if available, or NULL otherwise. ALIAS is the variable
1189 we are asking if REF can access. OFFSET and SIZE come from the
1190 memory access expression that generated this virtual operand.
1192 XXX: We should handle the NO_ALIAS attributes here. */
1194 static bool
1195 access_can_touch_variable (tree ref, tree alias, HOST_WIDE_INT offset,
1196 HOST_WIDE_INT size)
1198 bool offsetgtz = offset > 0;
1199 unsigned HOST_WIDE_INT uoffset = (unsigned HOST_WIDE_INT) offset;
1200 tree base = ref ? get_base_address (ref) : NULL;
1202 /* If ALIAS is .GLOBAL_VAR then the memory reference REF must be
1203 using a call-clobbered memory tag. By definition, call-clobbered
1204 memory tags can always touch .GLOBAL_VAR. */
1205 if (alias == gimple_global_var (cfun))
1206 return true;
1208 /* If ref is a TARGET_MEM_REF, just return true, as we can't really
1209 disambiguate them right now. */
1210 if (ref && TREE_CODE (ref) == TARGET_MEM_REF)
1211 return true;
1213 /* If ALIAS is an SFT, it can't be touched if the offset
1214 and size of the access is not overlapping with the SFT offset and
1215 size. This is only true if we are accessing through a pointer
1216 to a type that is the same as SFT_PARENT_VAR. Otherwise, we may
1217 be accessing through a pointer to some substruct of the
1218 structure, and if we try to prune there, we will have the wrong
1219 offset, and get the wrong answer.
1220 i.e., we can't prune without more work if we have something like
1222 struct gcc_target
1224 struct asm_out
1226 const char *byte_op;
1227 struct asm_int_op
1229 const char *hi;
1230 } aligned_op;
1231 } asm_out;
1232 } targetm;
1234 foo = &targetm.asm_out.aligned_op;
1235 return foo->hi;
1237 SFT.1, which represents hi, will have SFT_OFFSET=32 because in
1238 terms of SFT_PARENT_VAR, that is where it is.
1239 However, the access through the foo pointer will be at offset 0. */
1240 if (size != -1
1241 && TREE_CODE (alias) == STRUCT_FIELD_TAG
1242 && base
1243 && TREE_TYPE (base) == TREE_TYPE (SFT_PARENT_VAR (alias))
1244 && !overlap_subvar (offset, size, alias, NULL))
1246 #ifdef ACCESS_DEBUGGING
1247 fprintf (stderr, "Access to ");
1248 print_generic_expr (stderr, ref, 0);
1249 fprintf (stderr, " may not touch ");
1250 print_generic_expr (stderr, alias, 0);
1251 fprintf (stderr, " in function %s\n", get_name (current_function_decl));
1252 #endif
1253 return false;
1256 /* Without strict aliasing, it is impossible for a component access
1257 through a pointer to touch a random variable, unless that
1258 variable *is* a structure or a pointer.
1260 That is, given p->c, and some random global variable b,
1261 there is no legal way that p->c could be an access to b.
1263 Without strict aliasing on, we consider it legal to do something
1264 like:
1266 struct foos { int l; };
1267 int foo;
1268 static struct foos *getfoo(void);
1269 int main (void)
1271 struct foos *f = getfoo();
1272 f->l = 1;
1273 foo = 2;
1274 if (f->l == 1)
1275 abort();
1276 exit(0);
1278 static struct foos *getfoo(void)
1279 { return (struct foos *)&foo; }
1281 (taken from 20000623-1.c)
1283 The docs also say/imply that access through union pointers
1284 is legal (but *not* if you take the address of the union member,
1285 i.e. the inverse), such that you can do
1287 typedef union {
1288 int d;
1289 } U;
1291 int rv;
1292 void breakme()
1294 U *rv0;
1295 U *pretmp = (U*)&rv;
1296 rv0 = pretmp;
1297 rv0->d = 42;
1299 To implement this, we just punt on accesses through union
1300 pointers entirely.
1302 Another case we have to allow is accessing a variable
1303 through an array access at offset zero. This happens from
1304 code generated by the fortran frontend like
1306 char[1:1] & my_char_ref;
1307 char my_char;
1308 my_char_ref_1 = (char[1:1] &) &my_char;
1309 D.874_2 = (*my_char_ref_1)[1]{lb: 1 sz: 1};
1311 else if (ref
1312 && flag_strict_aliasing
1313 && TREE_CODE (ref) != INDIRECT_REF
1314 && !MTAG_P (alias)
1315 && base
1316 && (TREE_CODE (base) != INDIRECT_REF
1317 || TREE_CODE (TREE_TYPE (base)) != UNION_TYPE)
1318 && (TREE_CODE (base) != INDIRECT_REF
1319 || TREE_CODE (ref) != ARRAY_REF
1320 || offset != 0
1321 || (DECL_SIZE (alias)
1322 && TREE_CODE (DECL_SIZE (alias)) == INTEGER_CST
1323 && size != -1
1324 && (unsigned HOST_WIDE_INT)size
1325 != TREE_INT_CST_LOW (DECL_SIZE (alias))))
1326 && !AGGREGATE_TYPE_P (TREE_TYPE (alias))
1327 && TREE_CODE (TREE_TYPE (alias)) != COMPLEX_TYPE
1328 && !var_ann (alias)->is_heapvar
1329 /* When the struct has may_alias attached to it, we need not to
1330 return true. */
1331 && get_alias_set (base))
1333 #ifdef ACCESS_DEBUGGING
1334 fprintf (stderr, "Access to ");
1335 print_generic_expr (stderr, ref, 0);
1336 fprintf (stderr, " may not touch ");
1337 print_generic_expr (stderr, alias, 0);
1338 fprintf (stderr, " in function %s\n", get_name (current_function_decl));
1339 #endif
1340 return false;
1343 /* If the offset of the access is greater than the size of one of
1344 the possible aliases, it can't be touching that alias, because it
1345 would be past the end of the structure. */
1346 else if (ref
1347 && flag_strict_aliasing
1348 && TREE_CODE (ref) != INDIRECT_REF
1349 && !MTAG_P (alias)
1350 && !POINTER_TYPE_P (TREE_TYPE (alias))
1351 && offsetgtz
1352 && DECL_SIZE (alias)
1353 && TREE_CODE (DECL_SIZE (alias)) == INTEGER_CST
1354 && uoffset > TREE_INT_CST_LOW (DECL_SIZE (alias)))
1356 #ifdef ACCESS_DEBUGGING
1357 fprintf (stderr, "Access to ");
1358 print_generic_expr (stderr, ref, 0);
1359 fprintf (stderr, " may not touch ");
1360 print_generic_expr (stderr, alias, 0);
1361 fprintf (stderr, " in function %s\n", get_name (current_function_decl));
1362 #endif
1363 return false;
1366 return true;
1369 /* Add the actual variables accessed, given a member of a points-to set
1370 that is the SFT VAR, where the access is of SIZE at OFFSET from VAR.
1371 IS_CALL_SITE is true if this is a call, and IS_DEF is true if this is
1372 supposed to be a vdef, and false if this should be a VUSE.
1374 The real purpose of this function is to take a points-to set for a
1375 pointer to a structure, say
1377 struct s {
1378 int a;
1379 int b;
1380 } foo, *foop = &foo;
1382 and discover which variables an access, such as foop->b, can alias.
1384 This is necessary because foop only actually points to foo's first
1385 member, so that is all the points-to set contains. However, an access
1386 to foop->a may be touching some single SFT if we have created some
1387 SFT's for a structure. */
1389 static bool
1390 add_vars_for_offset (tree var, unsigned HOST_WIDE_INT offset,
1391 unsigned HOST_WIDE_INT size, bool is_def)
1393 bool added = false;
1394 tree subvar;
1395 subvar_t sv;
1396 unsigned int i;
1398 /* Adjust offset by the pointed-to location. */
1399 offset += SFT_OFFSET (var);
1401 /* Add all subvars of var that overlap with the access.
1402 Binary search for the first relevant SFT. */
1403 sv = get_subvars_for_var (SFT_PARENT_VAR (var));
1404 if (!get_first_overlapping_subvar (sv, offset, size, &i))
1405 return false;
1407 for (; VEC_iterate (tree, sv, i, subvar); ++i)
1409 if (SFT_OFFSET (subvar) > offset
1410 && size <= SFT_OFFSET (subvar) - offset)
1411 break;
1413 if (is_def)
1414 append_vdef (subvar);
1415 else
1416 append_vuse (subvar);
1417 added = true;
1420 return added;
1424 /* Add VAR to the virtual operands array. FLAGS is as in
1425 get_expr_operands. FULL_REF is a tree that contains the entire
1426 pointer dereference expression, if available, or NULL otherwise.
1427 OFFSET and SIZE come from the memory access expression that
1428 generated this virtual operand. IS_CALL_SITE is true if the
1429 affected statement is a call site. */
1431 static void
1432 add_virtual_operand (tree var, stmt_ann_t s_ann, int flags,
1433 tree full_ref, HOST_WIDE_INT offset,
1434 HOST_WIDE_INT size, bool is_call_site)
1436 bitmap aliases = NULL;
1437 tree sym;
1438 var_ann_t v_ann;
1440 sym = (TREE_CODE (var) == SSA_NAME ? SSA_NAME_VAR (var) : var);
1441 v_ann = var_ann (sym);
1443 /* Mark the statement as having memory operands. */
1444 s_ann->references_memory = true;
1446 /* If the variable cannot be modified and this is a VDEF change
1447 it into a VUSE. This happens when read-only variables are marked
1448 call-clobbered and/or aliased to writable variables. So we only
1449 check that this only happens on non-specific stores.
1451 Note that if this is a specific store, i.e. associated with a
1452 GIMPLE_MODIFY_STMT, then we can't suppress the VDEF, lest we run
1453 into validation problems.
1455 This can happen when programs cast away const, leaving us with a
1456 store to read-only memory. If the statement is actually executed
1457 at runtime, then the program is ill formed. If the statement is
1458 not executed then all is well. At the very least, we cannot ICE. */
1459 if ((flags & opf_implicit) && unmodifiable_var_p (var))
1460 flags &= ~opf_def;
1462 /* The variable is not a GIMPLE register. Add it (or its aliases) to
1463 virtual operands, unless the caller has specifically requested
1464 not to add virtual operands (used when adding operands inside an
1465 ADDR_EXPR expression). */
1466 if (flags & opf_no_vops)
1467 return;
1469 if (MTAG_P (var))
1470 aliases = MTAG_ALIASES (var);
1472 if (aliases == NULL)
1474 if (!gimple_aliases_computed_p (cfun)
1475 && (flags & opf_def))
1476 s_ann->has_volatile_ops = true;
1478 /* The variable is not aliased or it is an alias tag. */
1479 if (flags & opf_def)
1480 append_vdef (var);
1481 else
1482 append_vuse (var);
1484 else
1486 bitmap_iterator bi;
1487 unsigned int i;
1488 bool none_added = true;
1490 /* The variable is aliased. Add its aliases to the virtual
1491 operands. */
1492 gcc_assert (!bitmap_empty_p (aliases));
1494 EXECUTE_IF_SET_IN_BITMAP (aliases, 0, i, bi)
1496 tree al = referenced_var (i);
1498 /* For SFTs we have to consider all subvariables of the parent var
1499 if it is a potential points-to location. */
1500 if (TREE_CODE (al) == STRUCT_FIELD_TAG
1501 && TREE_CODE (var) == NAME_MEMORY_TAG)
1503 if (SFT_BASE_FOR_COMPONENTS_P (al))
1505 /* If AL is the first SFT of a component, it can be used
1506 to find other SFTs at [offset, size] adjacent to it. */
1507 none_added &= !add_vars_for_offset (al, offset, size,
1508 flags & opf_def);
1510 else if ((unsigned HOST_WIDE_INT)offset < SFT_SIZE (al))
1512 /* Otherwise, we only need to consider it if
1513 [offset, size] overlaps with AL. */
1514 if (flags & opf_def)
1515 append_vdef (al);
1516 else
1517 append_vuse (al);
1518 none_added = false;
1521 else
1523 /* Call-clobbered tags may have non-call-clobbered
1524 symbols in their alias sets. Ignore them if we are
1525 adding VOPs for a call site. */
1526 if (is_call_site && !is_call_clobbered (al))
1527 continue;
1529 /* If we do not know the full reference tree or if the access is
1530 unspecified [0, -1], we cannot prune it. Otherwise try doing
1531 so using access_can_touch_variable. */
1532 if (full_ref
1533 && !access_can_touch_variable (full_ref, al, offset, size))
1534 continue;
1536 if (flags & opf_def)
1537 append_vdef (al);
1538 else
1539 append_vuse (al);
1540 none_added = false;
1544 if (flags & opf_def)
1546 /* If the variable is also an alias tag, add a virtual
1547 operand for it, otherwise we will miss representing
1548 references to the members of the variable's alias set.
1549 This fixes the bug in gcc.c-torture/execute/20020503-1.c.
1551 It is also necessary to add bare defs on clobbers for
1552 SMT's, so that bare SMT uses caused by pruning all the
1553 aliases will link up properly with calls. In order to
1554 keep the number of these bare defs we add down to the
1555 minimum necessary, we keep track of which SMT's were used
1556 alone in statement vdefs or VUSEs. */
1557 if (none_added
1558 || (TREE_CODE (var) == SYMBOL_MEMORY_TAG
1559 && is_call_site))
1560 append_vdef (var);
1562 else
1564 /* Even if no aliases have been added, we still need to
1565 establish def-use and use-def chains, lest
1566 transformations think that this is not a memory
1567 reference. For an example of this scenario, see
1568 testsuite/g++.dg/opt/cleanup1.C. */
1569 if (none_added)
1570 append_vuse (var);
1576 /* Add *VAR_P to the appropriate operand array for S_ANN. FLAGS is as in
1577 get_expr_operands. If *VAR_P is a GIMPLE register, it will be added to
1578 the statement's real operands, otherwise it is added to virtual
1579 operands. */
1581 static void
1582 add_stmt_operand (tree *var_p, stmt_ann_t s_ann, int flags)
1584 tree var, sym;
1585 var_ann_t v_ann;
1587 gcc_assert (SSA_VAR_P (*var_p) && s_ann);
1589 var = *var_p;
1590 sym = (TREE_CODE (var) == SSA_NAME ? SSA_NAME_VAR (var) : var);
1591 v_ann = var_ann (sym);
1593 /* Mark statements with volatile operands. */
1594 if (TREE_THIS_VOLATILE (sym))
1595 s_ann->has_volatile_ops = true;
1597 if (is_gimple_reg (sym))
1599 /* The variable is a GIMPLE register. Add it to real operands. */
1600 if (flags & opf_def)
1601 append_def (var_p);
1602 else
1603 append_use (var_p);
1605 else
1606 add_virtual_operand (var, s_ann, flags, NULL_TREE, 0, -1, false);
1609 /* Subroutine of get_indirect_ref_operands. ADDR is the address
1610 that is dereferenced, the meaning of the rest of the arguments
1611 is the same as in get_indirect_ref_operands. */
1613 static void
1614 get_addr_dereference_operands (tree stmt, tree *addr, int flags, tree full_ref,
1615 HOST_WIDE_INT offset, HOST_WIDE_INT size,
1616 bool recurse_on_base)
1618 tree ptr = *addr;
1619 stmt_ann_t s_ann = stmt_ann (stmt);
1621 s_ann->references_memory = true;
1623 if (SSA_VAR_P (ptr))
1625 struct ptr_info_def *pi = NULL;
1627 /* If PTR has flow-sensitive points-to information, use it. */
1628 if (TREE_CODE (ptr) == SSA_NAME
1629 && (pi = SSA_NAME_PTR_INFO (ptr)) != NULL
1630 && pi->name_mem_tag)
1632 /* PTR has its own memory tag. Use it. */
1633 add_virtual_operand (pi->name_mem_tag, s_ann, flags,
1634 full_ref, offset, size, false);
1636 else
1638 /* If PTR is not an SSA_NAME or it doesn't have a name
1639 tag, use its symbol memory tag. */
1640 var_ann_t v_ann;
1642 /* If we are emitting debugging dumps, display a warning if
1643 PTR is an SSA_NAME with no flow-sensitive alias
1644 information. That means that we may need to compute
1645 aliasing again or that a propagation pass forgot to
1646 update the alias information on the pointers. */
1647 if (dump_file
1648 && TREE_CODE (ptr) == SSA_NAME
1649 && (pi == NULL
1650 || pi->name_mem_tag == NULL_TREE))
1652 fprintf (dump_file,
1653 "NOTE: no flow-sensitive alias info for ");
1654 print_generic_expr (dump_file, ptr, dump_flags);
1655 fprintf (dump_file, " in ");
1656 print_generic_stmt (dump_file, stmt, 0);
1659 if (TREE_CODE (ptr) == SSA_NAME)
1660 ptr = SSA_NAME_VAR (ptr);
1661 v_ann = var_ann (ptr);
1663 /* If we don't know what this pointer points to then we have
1664 to make sure to not prune virtual operands based on offset
1665 and size. */
1666 if (v_ann->symbol_mem_tag)
1668 add_virtual_operand (v_ann->symbol_mem_tag, s_ann, flags,
1669 full_ref, 0, -1, false);
1670 /* Make sure we add the SMT itself. */
1671 if (!(flags & opf_no_vops))
1673 if (flags & opf_def)
1674 append_vdef (v_ann->symbol_mem_tag);
1675 else
1676 append_vuse (v_ann->symbol_mem_tag);
1680 /* Aliasing information is missing; mark statement as
1681 volatile so we won't optimize it out too actively. */
1682 else if (!gimple_aliases_computed_p (cfun)
1683 && (flags & opf_def))
1684 s_ann->has_volatile_ops = true;
1687 else if (TREE_CODE (ptr) == INTEGER_CST)
1689 /* If a constant is used as a pointer, we can't generate a real
1690 operand for it but we mark the statement volatile to prevent
1691 optimizations from messing things up. */
1692 s_ann->has_volatile_ops = true;
1693 return;
1695 else
1697 /* Ok, this isn't even is_gimple_min_invariant. Something's broke. */
1698 gcc_unreachable ();
1701 /* If requested, add a USE operand for the base pointer. */
1702 if (recurse_on_base)
1703 get_expr_operands (stmt, addr, opf_use);
1707 /* A subroutine of get_expr_operands to handle INDIRECT_REF,
1708 ALIGN_INDIRECT_REF and MISALIGNED_INDIRECT_REF.
1710 STMT is the statement being processed, EXPR is the INDIRECT_REF
1711 that got us here.
1713 FLAGS is as in get_expr_operands.
1715 FULL_REF contains the full pointer dereference expression, if we
1716 have it, or NULL otherwise.
1718 OFFSET and SIZE are the location of the access inside the
1719 dereferenced pointer, if known.
1721 RECURSE_ON_BASE should be set to true if we want to continue
1722 calling get_expr_operands on the base pointer, and false if
1723 something else will do it for us. */
1725 static void
1726 get_indirect_ref_operands (tree stmt, tree expr, int flags, tree full_ref,
1727 HOST_WIDE_INT offset, HOST_WIDE_INT size,
1728 bool recurse_on_base)
1730 tree *pptr = &TREE_OPERAND (expr, 0);
1731 stmt_ann_t s_ann = stmt_ann (stmt);
1733 if (TREE_THIS_VOLATILE (expr))
1734 s_ann->has_volatile_ops = true;
1736 get_addr_dereference_operands (stmt, pptr, flags, full_ref, offset, size,
1737 recurse_on_base);
1741 /* A subroutine of get_expr_operands to handle TARGET_MEM_REF. */
1743 static void
1744 get_tmr_operands (tree stmt, tree expr, int flags)
1746 tree tag;
1747 stmt_ann_t s_ann = stmt_ann (stmt);
1749 /* This statement references memory. */
1750 s_ann->references_memory = 1;
1752 /* First record the real operands. */
1753 get_expr_operands (stmt, &TMR_BASE (expr), opf_use);
1754 get_expr_operands (stmt, &TMR_INDEX (expr), opf_use);
1756 if (TMR_SYMBOL (expr))
1757 add_to_addressable_set (TMR_SYMBOL (expr), &s_ann->addresses_taken);
1759 tag = TMR_TAG (expr);
1760 if (!tag)
1762 /* Something weird, so ensure that we will be careful. */
1763 s_ann->has_volatile_ops = true;
1764 return;
1766 if (!MTAG_P (tag))
1768 get_expr_operands (stmt, &tag, flags);
1769 return;
1772 add_virtual_operand (tag, s_ann, flags, expr, 0, -1, false);
1776 /* Add clobbering definitions for .GLOBAL_VAR or for each of the call
1777 clobbered variables in the function. */
1779 static void
1780 add_call_clobber_ops (tree stmt, tree callee)
1782 unsigned u;
1783 bitmap_iterator bi;
1784 stmt_ann_t s_ann = stmt_ann (stmt);
1785 bitmap not_read_b, not_written_b;
1787 /* If we created .GLOBAL_VAR earlier, just use it. */
1788 if (gimple_global_var (cfun))
1790 tree var = gimple_global_var (cfun);
1791 add_virtual_operand (var, s_ann, opf_def, NULL, 0, -1, true);
1792 return;
1795 /* Get info for local and module level statics. There is a bit
1796 set for each static if the call being processed does not read
1797 or write that variable. */
1798 not_read_b = callee ? ipa_reference_get_not_read_global (callee) : NULL;
1799 not_written_b = callee ? ipa_reference_get_not_written_global (callee) : NULL;
1801 /* Add a VDEF operand for every call clobbered variable. */
1802 EXECUTE_IF_SET_IN_BITMAP (gimple_call_clobbered_vars (cfun), 0, u, bi)
1804 tree var = referenced_var_lookup (u);
1805 unsigned int escape_mask = var_ann (var)->escape_mask;
1806 tree real_var = var;
1807 bool not_read;
1808 bool not_written;
1810 /* Not read and not written are computed on regular vars, not
1811 subvars, so look at the parent var if this is an SFT. */
1812 if (TREE_CODE (var) == STRUCT_FIELD_TAG)
1813 real_var = SFT_PARENT_VAR (var);
1815 not_read = not_read_b
1816 ? bitmap_bit_p (not_read_b, DECL_UID (real_var))
1817 : false;
1819 not_written = not_written_b
1820 ? bitmap_bit_p (not_written_b, DECL_UID (real_var))
1821 : false;
1822 gcc_assert (!unmodifiable_var_p (var));
1824 clobber_stats.clobbered_vars++;
1826 /* See if this variable is really clobbered by this function. */
1828 /* Trivial case: Things escaping only to pure/const are not
1829 clobbered by non-pure-const, and only read by pure/const. */
1830 if ((escape_mask & ~(ESCAPE_TO_PURE_CONST)) == 0)
1832 tree call = get_call_expr_in (stmt);
1833 if (call_expr_flags (call) & (ECF_CONST | ECF_PURE))
1835 add_virtual_operand (var, s_ann, opf_use, NULL, 0, -1, true);
1836 clobber_stats.unescapable_clobbers_avoided++;
1837 continue;
1839 else
1841 clobber_stats.unescapable_clobbers_avoided++;
1842 continue;
1846 if (not_written)
1848 clobber_stats.static_write_clobbers_avoided++;
1849 if (!not_read)
1850 add_virtual_operand (var, s_ann, opf_use, NULL, 0, -1, true);
1851 else
1852 clobber_stats.static_read_clobbers_avoided++;
1854 else
1855 add_virtual_operand (var, s_ann, opf_def, NULL, 0, -1, true);
1860 /* Add VUSE operands for .GLOBAL_VAR or all call clobbered variables in the
1861 function. */
1863 static void
1864 add_call_read_ops (tree stmt, tree callee)
1866 unsigned u;
1867 bitmap_iterator bi;
1868 stmt_ann_t s_ann = stmt_ann (stmt);
1869 bitmap not_read_b;
1871 /* if the function is not pure, it may reference memory. Add
1872 a VUSE for .GLOBAL_VAR if it has been created. See add_referenced_var
1873 for the heuristic used to decide whether to create .GLOBAL_VAR. */
1874 if (gimple_global_var (cfun))
1876 tree var = gimple_global_var (cfun);
1877 add_virtual_operand (var, s_ann, opf_use, NULL, 0, -1, true);
1878 return;
1881 not_read_b = callee ? ipa_reference_get_not_read_global (callee) : NULL;
1883 /* Add a VUSE for each call-clobbered variable. */
1884 EXECUTE_IF_SET_IN_BITMAP (gimple_call_clobbered_vars (cfun), 0, u, bi)
1886 tree var = referenced_var (u);
1887 tree real_var = var;
1888 bool not_read;
1890 clobber_stats.readonly_clobbers++;
1892 /* Not read and not written are computed on regular vars, not
1893 subvars, so look at the parent var if this is an SFT. */
1895 if (TREE_CODE (var) == STRUCT_FIELD_TAG)
1896 real_var = SFT_PARENT_VAR (var);
1898 not_read = not_read_b ? bitmap_bit_p (not_read_b, DECL_UID (real_var))
1899 : false;
1901 if (not_read)
1903 clobber_stats.static_readonly_clobbers_avoided++;
1904 continue;
1907 add_virtual_operand (var, s_ann, opf_use, NULL, 0, -1, true);
1912 /* A subroutine of get_expr_operands to handle CALL_EXPR. */
1914 static void
1915 get_call_expr_operands (tree stmt, tree expr)
1917 int call_flags = call_expr_flags (expr);
1918 int i, nargs;
1919 stmt_ann_t ann = stmt_ann (stmt);
1921 ann->references_memory = true;
1923 /* If aliases have been computed already, add VDEF or VUSE
1924 operands for all the symbols that have been found to be
1925 call-clobbered. */
1926 if (gimple_aliases_computed_p (cfun)
1927 && !(call_flags & ECF_NOVOPS))
1929 /* A 'pure' or a 'const' function never call-clobbers anything.
1930 A 'noreturn' function might, but since we don't return anyway
1931 there is no point in recording that. */
1932 if (TREE_SIDE_EFFECTS (expr)
1933 && !(call_flags & (ECF_PURE | ECF_CONST | ECF_NORETURN)))
1934 add_call_clobber_ops (stmt, get_callee_fndecl (expr));
1935 else if (!(call_flags & ECF_CONST))
1936 add_call_read_ops (stmt, get_callee_fndecl (expr));
1939 /* Find uses in the called function. */
1940 get_expr_operands (stmt, &CALL_EXPR_FN (expr), opf_use);
1941 nargs = call_expr_nargs (expr);
1942 for (i = 0; i < nargs; i++)
1943 get_expr_operands (stmt, &CALL_EXPR_ARG (expr, i), opf_use);
1945 get_expr_operands (stmt, &CALL_EXPR_STATIC_CHAIN (expr), opf_use);
1949 /* Scan operands in the ASM_EXPR stmt referred to in INFO. */
1951 static void
1952 get_asm_expr_operands (tree stmt)
1954 stmt_ann_t s_ann;
1955 int i, noutputs;
1956 const char **oconstraints;
1957 const char *constraint;
1958 bool allows_mem, allows_reg, is_inout;
1959 tree link;
1961 s_ann = stmt_ann (stmt);
1962 noutputs = list_length (ASM_OUTPUTS (stmt));
1963 oconstraints = (const char **) alloca ((noutputs) * sizeof (const char *));
1965 /* Gather all output operands. */
1966 for (i = 0, link = ASM_OUTPUTS (stmt); link; i++, link = TREE_CHAIN (link))
1968 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
1969 oconstraints[i] = constraint;
1970 parse_output_constraint (&constraint, i, 0, 0, &allows_mem,
1971 &allows_reg, &is_inout);
1973 /* This should have been split in gimplify_asm_expr. */
1974 gcc_assert (!allows_reg || !is_inout);
1976 /* Memory operands are addressable. Note that STMT needs the
1977 address of this operand. */
1978 if (!allows_reg && allows_mem)
1980 tree t = get_base_address (TREE_VALUE (link));
1981 if (t && DECL_P (t) && s_ann)
1982 add_to_addressable_set (t, &s_ann->addresses_taken);
1985 get_expr_operands (stmt, &TREE_VALUE (link), opf_def);
1988 /* Gather all input operands. */
1989 for (link = ASM_INPUTS (stmt); link; link = TREE_CHAIN (link))
1991 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
1992 parse_input_constraint (&constraint, 0, 0, noutputs, 0, oconstraints,
1993 &allows_mem, &allows_reg);
1995 /* Memory operands are addressable. Note that STMT needs the
1996 address of this operand. */
1997 if (!allows_reg && allows_mem)
1999 tree t = get_base_address (TREE_VALUE (link));
2000 if (t && DECL_P (t) && s_ann)
2001 add_to_addressable_set (t, &s_ann->addresses_taken);
2004 get_expr_operands (stmt, &TREE_VALUE (link), 0);
2007 /* Clobber all memory and addressable symbols for asm ("" : : : "memory"); */
2008 for (link = ASM_CLOBBERS (stmt); link; link = TREE_CHAIN (link))
2009 if (strcmp (TREE_STRING_POINTER (TREE_VALUE (link)), "memory") == 0)
2011 unsigned i;
2012 bitmap_iterator bi;
2014 s_ann->references_memory = true;
2016 EXECUTE_IF_SET_IN_BITMAP (gimple_call_clobbered_vars (cfun), 0, i, bi)
2018 tree var = referenced_var (i);
2019 add_stmt_operand (&var, s_ann, opf_def | opf_implicit);
2022 EXECUTE_IF_SET_IN_BITMAP (gimple_addressable_vars (cfun), 0, i, bi)
2024 tree var = referenced_var (i);
2026 /* Subvars are explicitly represented in this list, so we
2027 don't need the original to be added to the clobber ops,
2028 but the original *will* be in this list because we keep
2029 the addressability of the original variable up-to-date
2030 to avoid confusing the back-end. */
2031 if (var_can_have_subvars (var)
2032 && get_subvars_for_var (var) != NULL)
2033 continue;
2035 add_stmt_operand (&var, s_ann, opf_def | opf_implicit);
2037 break;
2042 /* Scan operands for the assignment expression EXPR in statement STMT. */
2044 static void
2045 get_modify_stmt_operands (tree stmt, tree expr)
2047 /* First get operands from the RHS. */
2048 get_expr_operands (stmt, &GIMPLE_STMT_OPERAND (expr, 1), opf_use);
2050 /* For the LHS, use a regular definition (opf_def) for GIMPLE
2051 registers. If the LHS is a store to memory, we will need
2052 a preserving definition (VDEF).
2054 Preserving definitions are those that modify a part of an
2055 aggregate object for which no subvars have been computed (or the
2056 reference does not correspond exactly to one of them). Stores
2057 through a pointer are also represented with VDEF operators.
2059 We used to distinguish between preserving and killing definitions.
2060 We always emit preserving definitions now. */
2061 get_expr_operands (stmt, &GIMPLE_STMT_OPERAND (expr, 0), opf_def);
2065 /* Recursively scan the expression pointed to by EXPR_P in statement
2066 STMT. FLAGS is one of the OPF_* constants modifying how to
2067 interpret the operands found. */
2069 static void
2070 get_expr_operands (tree stmt, tree *expr_p, int flags)
2072 enum tree_code code;
2073 enum tree_code_class codeclass;
2074 tree expr = *expr_p;
2075 stmt_ann_t s_ann = stmt_ann (stmt);
2077 if (expr == NULL)
2078 return;
2080 code = TREE_CODE (expr);
2081 codeclass = TREE_CODE_CLASS (code);
2083 switch (code)
2085 case ADDR_EXPR:
2086 /* Taking the address of a variable does not represent a
2087 reference to it, but the fact that the statement takes its
2088 address will be of interest to some passes (e.g. alias
2089 resolution). */
2090 add_to_addressable_set (TREE_OPERAND (expr, 0), &s_ann->addresses_taken);
2092 /* If the address is invariant, there may be no interesting
2093 variable references inside. */
2094 if (is_gimple_min_invariant (expr))
2095 return;
2097 /* Otherwise, there may be variables referenced inside but there
2098 should be no VUSEs created, since the referenced objects are
2099 not really accessed. The only operands that we should find
2100 here are ARRAY_REF indices which will always be real operands
2101 (GIMPLE does not allow non-registers as array indices). */
2102 flags |= opf_no_vops;
2103 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2104 return;
2106 case SSA_NAME:
2107 case STRUCT_FIELD_TAG:
2108 case SYMBOL_MEMORY_TAG:
2109 case NAME_MEMORY_TAG:
2110 add_stmt_operand (expr_p, s_ann, flags);
2111 return;
2113 case VAR_DECL:
2114 case PARM_DECL:
2115 case RESULT_DECL:
2117 subvar_t svars;
2119 /* Add the subvars for a variable, if it has subvars, to DEFS
2120 or USES. Otherwise, add the variable itself. Whether it
2121 goes to USES or DEFS depends on the operand flags. */
2122 if (var_can_have_subvars (expr)
2123 && (svars = get_subvars_for_var (expr)))
2125 unsigned int i;
2126 tree subvar;
2127 for (i = 0; VEC_iterate (tree, svars, i, subvar); ++i)
2128 add_stmt_operand (&subvar, s_ann, flags);
2130 else
2131 add_stmt_operand (expr_p, s_ann, flags);
2133 return;
2136 case MISALIGNED_INDIRECT_REF:
2137 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), flags);
2138 /* fall through */
2140 case ALIGN_INDIRECT_REF:
2141 case INDIRECT_REF:
2142 get_indirect_ref_operands (stmt, expr, flags, expr, 0, -1, true);
2143 return;
2145 case TARGET_MEM_REF:
2146 get_tmr_operands (stmt, expr, flags);
2147 return;
2149 case ARRAY_REF:
2150 case ARRAY_RANGE_REF:
2151 case COMPONENT_REF:
2152 case REALPART_EXPR:
2153 case IMAGPART_EXPR:
2155 tree ref;
2156 HOST_WIDE_INT offset, size, maxsize;
2157 bool none = true;
2159 if (TREE_THIS_VOLATILE (expr))
2160 s_ann->has_volatile_ops = true;
2162 /* This component reference becomes an access to all of the
2163 subvariables it can touch, if we can determine that, but
2164 *NOT* the real one. If we can't determine which fields we
2165 could touch, the recursion will eventually get to a
2166 variable and add *all* of its subvars, or whatever is the
2167 minimum correct subset. */
2168 ref = get_ref_base_and_extent (expr, &offset, &size, &maxsize);
2169 if (SSA_VAR_P (ref) && get_subvars_for_var (ref))
2171 subvar_t svars = get_subvars_for_var (ref);
2172 unsigned int i;
2173 tree subvar;
2175 for (i = 0; VEC_iterate (tree, svars, i, subvar); ++i)
2177 bool exact;
2179 if (overlap_subvar (offset, maxsize, subvar, &exact))
2181 int subvar_flags = flags;
2182 none = false;
2183 add_stmt_operand (&subvar, s_ann, subvar_flags);
2187 if (!none)
2188 flags |= opf_no_vops;
2190 if ((DECL_P (ref) && TREE_THIS_VOLATILE (ref))
2191 || (TREE_CODE (ref) == SSA_NAME
2192 && TREE_THIS_VOLATILE (SSA_NAME_VAR (ref))))
2193 s_ann->has_volatile_ops = true;
2195 else if (TREE_CODE (ref) == INDIRECT_REF)
2197 get_indirect_ref_operands (stmt, ref, flags, expr, offset,
2198 maxsize, false);
2199 flags |= opf_no_vops;
2202 /* Even if we found subvars above we need to ensure to see
2203 immediate uses for d in s.a[d]. In case of s.a having
2204 a subvar or we would miss it otherwise. */
2205 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2207 if (code == COMPONENT_REF)
2209 if (TREE_THIS_VOLATILE (TREE_OPERAND (expr, 1)))
2210 s_ann->has_volatile_ops = true;
2211 get_expr_operands (stmt, &TREE_OPERAND (expr, 2), opf_use);
2213 else if (code == ARRAY_REF || code == ARRAY_RANGE_REF)
2215 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), opf_use);
2216 get_expr_operands (stmt, &TREE_OPERAND (expr, 2), opf_use);
2217 get_expr_operands (stmt, &TREE_OPERAND (expr, 3), opf_use);
2220 return;
2223 case WITH_SIZE_EXPR:
2224 /* WITH_SIZE_EXPR is a pass-through reference to its first argument,
2225 and an rvalue reference to its second argument. */
2226 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), opf_use);
2227 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2228 return;
2230 case CALL_EXPR:
2231 get_call_expr_operands (stmt, expr);
2232 return;
2234 case COND_EXPR:
2235 case VEC_COND_EXPR:
2236 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), opf_use);
2237 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), opf_use);
2238 get_expr_operands (stmt, &TREE_OPERAND (expr, 2), opf_use);
2239 return;
2241 case GIMPLE_MODIFY_STMT:
2242 get_modify_stmt_operands (stmt, expr);
2243 return;
2245 case CONSTRUCTOR:
2247 /* General aggregate CONSTRUCTORs have been decomposed, but they
2248 are still in use as the COMPLEX_EXPR equivalent for vectors. */
2249 constructor_elt *ce;
2250 unsigned HOST_WIDE_INT idx;
2252 for (idx = 0;
2253 VEC_iterate (constructor_elt, CONSTRUCTOR_ELTS (expr), idx, ce);
2254 idx++)
2255 get_expr_operands (stmt, &ce->value, opf_use);
2257 return;
2260 case BIT_FIELD_REF:
2261 case TRUTH_NOT_EXPR:
2262 case VIEW_CONVERT_EXPR:
2263 do_unary:
2264 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2265 return;
2267 case TRUTH_AND_EXPR:
2268 case TRUTH_OR_EXPR:
2269 case TRUTH_XOR_EXPR:
2270 case COMPOUND_EXPR:
2271 case OBJ_TYPE_REF:
2272 case ASSERT_EXPR:
2273 do_binary:
2275 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2276 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), flags);
2277 return;
2280 case DOT_PROD_EXPR:
2281 case REALIGN_LOAD_EXPR:
2283 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2284 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), flags);
2285 get_expr_operands (stmt, &TREE_OPERAND (expr, 2), flags);
2286 return;
2289 case CHANGE_DYNAMIC_TYPE_EXPR:
2290 get_expr_operands (stmt, &CHANGE_DYNAMIC_TYPE_LOCATION (expr), opf_use);
2291 return;
2293 case OMP_FOR:
2295 tree init = OMP_FOR_INIT (expr);
2296 tree cond = OMP_FOR_COND (expr);
2297 tree incr = OMP_FOR_INCR (expr);
2298 tree c, clauses = OMP_FOR_CLAUSES (stmt);
2300 get_expr_operands (stmt, &GIMPLE_STMT_OPERAND (init, 0), opf_def);
2301 get_expr_operands (stmt, &GIMPLE_STMT_OPERAND (init, 1), opf_use);
2302 get_expr_operands (stmt, &TREE_OPERAND (cond, 1), opf_use);
2303 get_expr_operands (stmt,
2304 &TREE_OPERAND (GIMPLE_STMT_OPERAND (incr, 1), 1),
2305 opf_use);
2307 c = find_omp_clause (clauses, OMP_CLAUSE_SCHEDULE);
2308 if (c)
2309 get_expr_operands (stmt, &OMP_CLAUSE_SCHEDULE_CHUNK_EXPR (c),
2310 opf_use);
2311 return;
2314 case OMP_CONTINUE:
2316 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), opf_def);
2317 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), opf_use);
2318 return;
2321 case OMP_PARALLEL:
2323 tree c, clauses = OMP_PARALLEL_CLAUSES (stmt);
2325 if (OMP_PARALLEL_DATA_ARG (stmt))
2327 get_expr_operands (stmt, &OMP_PARALLEL_DATA_ARG (stmt), opf_use);
2328 add_to_addressable_set (OMP_PARALLEL_DATA_ARG (stmt),
2329 &s_ann->addresses_taken);
2332 c = find_omp_clause (clauses, OMP_CLAUSE_IF);
2333 if (c)
2334 get_expr_operands (stmt, &OMP_CLAUSE_IF_EXPR (c), opf_use);
2335 c = find_omp_clause (clauses, OMP_CLAUSE_NUM_THREADS);
2336 if (c)
2337 get_expr_operands (stmt, &OMP_CLAUSE_NUM_THREADS_EXPR (c), opf_use);
2338 return;
2341 case OMP_SECTIONS:
2343 get_expr_operands (stmt, &OMP_SECTIONS_CONTROL (expr), opf_def);
2344 return;
2347 case OMP_ATOMIC_LOAD:
2349 tree *addr = &TREE_OPERAND (expr, 1);
2350 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), opf_def);
2352 if (TREE_CODE (*addr) == ADDR_EXPR)
2353 get_expr_operands (stmt, &TREE_OPERAND (*addr, 0), opf_def);
2354 else
2355 get_addr_dereference_operands (stmt, addr, opf_def,
2356 NULL_TREE, 0, -1, true);
2357 return;
2360 case OMP_ATOMIC_STORE:
2362 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), opf_use);
2363 return;
2366 case BLOCK:
2367 case FUNCTION_DECL:
2368 case EXC_PTR_EXPR:
2369 case FILTER_EXPR:
2370 case LABEL_DECL:
2371 case CONST_DECL:
2372 case OMP_SINGLE:
2373 case OMP_MASTER:
2374 case OMP_ORDERED:
2375 case OMP_CRITICAL:
2376 case OMP_RETURN:
2377 case OMP_SECTION:
2378 case OMP_SECTIONS_SWITCH:
2379 case PREDICT_EXPR:
2380 /* Expressions that make no memory references. */
2381 return;
2383 default:
2384 if (codeclass == tcc_unary)
2385 goto do_unary;
2386 if (codeclass == tcc_binary || codeclass == tcc_comparison)
2387 goto do_binary;
2388 if (codeclass == tcc_constant || codeclass == tcc_type)
2389 return;
2392 /* If we get here, something has gone wrong. */
2393 #ifdef ENABLE_CHECKING
2394 fprintf (stderr, "unhandled expression in get_expr_operands():\n");
2395 debug_tree (expr);
2396 fputs ("\n", stderr);
2397 #endif
2398 gcc_unreachable ();
2402 /* Parse STMT looking for operands. When finished, the various
2403 build_* operand vectors will have potential operands in them. */
2405 static void
2406 parse_ssa_operands (tree stmt)
2408 enum tree_code code;
2410 code = TREE_CODE (stmt);
2411 switch (code)
2413 case GIMPLE_MODIFY_STMT:
2414 get_modify_stmt_operands (stmt, stmt);
2415 break;
2417 case COND_EXPR:
2418 get_expr_operands (stmt, &COND_EXPR_COND (stmt), opf_use);
2419 break;
2421 case SWITCH_EXPR:
2422 get_expr_operands (stmt, &SWITCH_COND (stmt), opf_use);
2423 break;
2425 case ASM_EXPR:
2426 get_asm_expr_operands (stmt);
2427 break;
2429 case RETURN_EXPR:
2430 get_expr_operands (stmt, &TREE_OPERAND (stmt, 0), opf_use);
2431 break;
2433 case GOTO_EXPR:
2434 get_expr_operands (stmt, &GOTO_DESTINATION (stmt), opf_use);
2435 break;
2437 case LABEL_EXPR:
2438 get_expr_operands (stmt, &LABEL_EXPR_LABEL (stmt), opf_use);
2439 break;
2441 case BIND_EXPR:
2442 case CASE_LABEL_EXPR:
2443 case TRY_CATCH_EXPR:
2444 case TRY_FINALLY_EXPR:
2445 case EH_FILTER_EXPR:
2446 case CATCH_EXPR:
2447 case RESX_EXPR:
2448 /* These nodes contain no variable references. */
2449 break;
2451 default:
2452 /* Notice that if get_expr_operands tries to use &STMT as the
2453 operand pointer (which may only happen for USE operands), we
2454 will fail in add_stmt_operand. This default will handle
2455 statements like empty statements, or CALL_EXPRs that may
2456 appear on the RHS of a statement or as statements themselves. */
2457 get_expr_operands (stmt, &stmt, opf_use);
2458 break;
2463 /* Create an operands cache for STMT. */
2465 static void
2466 build_ssa_operands (tree stmt)
2468 stmt_ann_t ann = get_stmt_ann (stmt);
2470 /* Initially assume that the statement has no volatile operands and
2471 makes no memory references. */
2472 ann->has_volatile_ops = false;
2473 ann->references_memory = false;
2474 /* Just clear the bitmap so we don't end up reallocating it over and over. */
2475 if (ann->addresses_taken)
2476 bitmap_clear (ann->addresses_taken);
2478 start_ssa_stmt_operands ();
2479 parse_ssa_operands (stmt);
2480 operand_build_sort_virtual (build_vuses);
2481 operand_build_sort_virtual (build_vdefs);
2482 finalize_ssa_stmt_operands (stmt);
2484 if (ann->addresses_taken && bitmap_empty_p (ann->addresses_taken))
2485 ann->addresses_taken = NULL;
2487 /* For added safety, assume that statements with volatile operands
2488 also reference memory. */
2489 if (ann->has_volatile_ops)
2490 ann->references_memory = true;
2494 /* Releases the operands of STMT back to their freelists, and clears
2495 the stmt operand lists. */
2497 void
2498 free_stmt_operands (tree stmt)
2500 def_optype_p defs = DEF_OPS (stmt), last_def;
2501 use_optype_p uses = USE_OPS (stmt), last_use;
2502 voptype_p vuses = VUSE_OPS (stmt);
2503 voptype_p vdefs = VDEF_OPS (stmt), vdef, next_vdef;
2504 unsigned i;
2506 if (defs)
2508 for (last_def = defs; last_def->next; last_def = last_def->next)
2509 continue;
2510 last_def->next = gimple_ssa_operands (cfun)->free_defs;
2511 gimple_ssa_operands (cfun)->free_defs = defs;
2512 DEF_OPS (stmt) = NULL;
2515 if (uses)
2517 for (last_use = uses; last_use->next; last_use = last_use->next)
2518 delink_imm_use (USE_OP_PTR (last_use));
2519 delink_imm_use (USE_OP_PTR (last_use));
2520 last_use->next = gimple_ssa_operands (cfun)->free_uses;
2521 gimple_ssa_operands (cfun)->free_uses = uses;
2522 USE_OPS (stmt) = NULL;
2525 if (vuses)
2527 for (i = 0; i < VUSE_NUM (vuses); i++)
2528 delink_imm_use (VUSE_OP_PTR (vuses, i));
2529 add_vop_to_freelist (vuses);
2530 VUSE_OPS (stmt) = NULL;
2533 if (vdefs)
2535 for (vdef = vdefs; vdef; vdef = next_vdef)
2537 next_vdef = vdef->next;
2538 delink_imm_use (VDEF_OP_PTR (vdef, 0));
2539 add_vop_to_freelist (vdef);
2541 VDEF_OPS (stmt) = NULL;
2546 /* Free any operands vectors in OPS. */
2548 void
2549 free_ssa_operands (stmt_operands_p ops)
2551 ops->def_ops = NULL;
2552 ops->use_ops = NULL;
2553 ops->vdef_ops = NULL;
2554 ops->vuse_ops = NULL;
2555 BITMAP_FREE (ops->loads);
2556 BITMAP_FREE (ops->stores);
2560 /* Get the operands of statement STMT. */
2562 void
2563 update_stmt_operands (tree stmt)
2565 stmt_ann_t ann = get_stmt_ann (stmt);
2567 /* If update_stmt_operands is called before SSA is initialized, do
2568 nothing. */
2569 if (!ssa_operands_active ())
2570 return;
2572 /* The optimizers cannot handle statements that are nothing but a
2573 _DECL. This indicates a bug in the gimplifier. */
2574 gcc_assert (!SSA_VAR_P (stmt));
2576 timevar_push (TV_TREE_OPS);
2578 gcc_assert (ann->modified);
2579 build_ssa_operands (stmt);
2580 ann->modified = 0;
2582 timevar_pop (TV_TREE_OPS);
2586 /* Copies virtual operands from SRC to DST. */
2588 void
2589 copy_virtual_operands (tree dest, tree src)
2591 unsigned int i, n;
2592 voptype_p src_vuses, dest_vuses;
2593 voptype_p src_vdefs, dest_vdefs;
2594 struct voptype_d vuse;
2595 struct voptype_d vdef;
2596 stmt_ann_t dest_ann;
2598 VDEF_OPS (dest) = NULL;
2599 VUSE_OPS (dest) = NULL;
2601 dest_ann = get_stmt_ann (dest);
2602 BITMAP_FREE (dest_ann->operands.loads);
2603 BITMAP_FREE (dest_ann->operands.stores);
2605 if (LOADED_SYMS (src))
2607 dest_ann->operands.loads = BITMAP_ALLOC (&operands_bitmap_obstack);
2608 bitmap_copy (dest_ann->operands.loads, LOADED_SYMS (src));
2611 if (STORED_SYMS (src))
2613 dest_ann->operands.stores = BITMAP_ALLOC (&operands_bitmap_obstack);
2614 bitmap_copy (dest_ann->operands.stores, STORED_SYMS (src));
2617 /* Copy all the VUSE operators and corresponding operands. */
2618 dest_vuses = &vuse;
2619 for (src_vuses = VUSE_OPS (src); src_vuses; src_vuses = src_vuses->next)
2621 n = VUSE_NUM (src_vuses);
2622 dest_vuses = add_vuse_op (dest, NULL_TREE, n, dest_vuses);
2623 for (i = 0; i < n; i++)
2624 SET_USE (VUSE_OP_PTR (dest_vuses, i), VUSE_OP (src_vuses, i));
2626 if (VUSE_OPS (dest) == NULL)
2627 VUSE_OPS (dest) = vuse.next;
2630 /* Copy all the VDEF operators and corresponding operands. */
2631 dest_vdefs = &vdef;
2632 for (src_vdefs = VDEF_OPS (src); src_vdefs; src_vdefs = src_vdefs->next)
2634 n = VUSE_NUM (src_vdefs);
2635 dest_vdefs = add_vdef_op (dest, NULL_TREE, n, dest_vdefs);
2636 VDEF_RESULT (dest_vdefs) = VDEF_RESULT (src_vdefs);
2637 for (i = 0; i < n; i++)
2638 SET_USE (VUSE_OP_PTR (dest_vdefs, i), VUSE_OP (src_vdefs, i));
2640 if (VDEF_OPS (dest) == NULL)
2641 VDEF_OPS (dest) = vdef.next;
2646 /* Specifically for use in DOM's expression analysis. Given a store, we
2647 create an artificial stmt which looks like a load from the store, this can
2648 be used to eliminate redundant loads. OLD_OPS are the operands from the
2649 store stmt, and NEW_STMT is the new load which represents a load of the
2650 values stored. If DELINK_IMM_USES_P is specified, the immediate
2651 uses of this stmt will be de-linked. */
2653 void
2654 create_ssa_artificial_load_stmt (tree new_stmt, tree old_stmt,
2655 bool delink_imm_uses_p)
2657 tree op;
2658 ssa_op_iter iter;
2659 use_operand_p use_p;
2660 unsigned i;
2661 stmt_ann_t ann;
2663 /* Create the stmt annotation but make sure to not mark the stmt
2664 as modified as we will build operands ourselves. */
2665 ann = get_stmt_ann (new_stmt);
2666 ann->modified = 0;
2668 /* Process NEW_STMT looking for operands. */
2669 start_ssa_stmt_operands ();
2670 parse_ssa_operands (new_stmt);
2672 for (i = 0; VEC_iterate (tree, build_vuses, i, op); i++)
2673 if (TREE_CODE (op) != SSA_NAME)
2674 var_ann (op)->in_vuse_list = false;
2676 for (i = 0; VEC_iterate (tree, build_vdefs, i, op); i++)
2677 if (TREE_CODE (op) != SSA_NAME)
2678 var_ann (op)->in_vdef_list = false;
2680 /* Remove any virtual operands that were found. */
2681 VEC_truncate (tree, build_vdefs, 0);
2682 VEC_truncate (tree, build_vuses, 0);
2684 /* Clear the loads and stores bitmaps. */
2685 bitmap_clear (build_loads);
2686 bitmap_clear (build_stores);
2688 /* For each VDEF on the original statement, we want to create a
2689 VUSE of the VDEF result operand on the new statement. */
2690 FOR_EACH_SSA_TREE_OPERAND (op, old_stmt, iter, SSA_OP_VDEF)
2691 append_vuse (op);
2693 finalize_ssa_stmt_operands (new_stmt);
2695 /* All uses in this fake stmt must not be in the immediate use lists. */
2696 if (delink_imm_uses_p)
2697 FOR_EACH_SSA_USE_OPERAND (use_p, new_stmt, iter, SSA_OP_ALL_USES)
2698 delink_imm_use (use_p);
2702 /* Swap operands EXP0 and EXP1 in statement STMT. No attempt is done
2703 to test the validity of the swap operation. */
2705 void
2706 swap_tree_operands (tree stmt, tree *exp0, tree *exp1)
2708 tree op0, op1;
2709 op0 = *exp0;
2710 op1 = *exp1;
2712 /* If the operand cache is active, attempt to preserve the relative
2713 positions of these two operands in their respective immediate use
2714 lists. */
2715 if (ssa_operands_active () && op0 != op1)
2717 use_optype_p use0, use1, ptr;
2718 use0 = use1 = NULL;
2720 /* Find the 2 operands in the cache, if they are there. */
2721 for (ptr = USE_OPS (stmt); ptr; ptr = ptr->next)
2722 if (USE_OP_PTR (ptr)->use == exp0)
2724 use0 = ptr;
2725 break;
2728 for (ptr = USE_OPS (stmt); ptr; ptr = ptr->next)
2729 if (USE_OP_PTR (ptr)->use == exp1)
2731 use1 = ptr;
2732 break;
2735 /* If both uses don't have operand entries, there isn't much we can do
2736 at this point. Presumably we don't need to worry about it. */
2737 if (use0 && use1)
2739 tree *tmp = USE_OP_PTR (use1)->use;
2740 USE_OP_PTR (use1)->use = USE_OP_PTR (use0)->use;
2741 USE_OP_PTR (use0)->use = tmp;
2745 /* Now swap the data. */
2746 *exp0 = op1;
2747 *exp1 = op0;
2751 /* Add the base address of REF to the set *ADDRESSES_TAKEN. If
2752 *ADDRESSES_TAKEN is NULL, a new set is created. REF may be
2753 a single variable whose address has been taken or any other valid
2754 GIMPLE memory reference (structure reference, array, etc). If the
2755 base address of REF is a decl that has sub-variables, also add all
2756 of its sub-variables. */
2758 void
2759 add_to_addressable_set (tree ref, bitmap *addresses_taken)
2761 tree var;
2762 subvar_t svars;
2764 gcc_assert (addresses_taken);
2766 /* Note that it is *NOT OKAY* to use the target of a COMPONENT_REF
2767 as the only thing we take the address of. If VAR is a structure,
2768 taking the address of a field means that the whole structure may
2769 be referenced using pointer arithmetic. See PR 21407 and the
2770 ensuing mailing list discussion. */
2771 var = get_base_address (ref);
2772 if (var && SSA_VAR_P (var))
2774 if (*addresses_taken == NULL)
2775 *addresses_taken = BITMAP_GGC_ALLOC ();
2777 if (var_can_have_subvars (var)
2778 && (svars = get_subvars_for_var (var)))
2780 unsigned int i;
2781 tree subvar;
2782 for (i = 0; VEC_iterate (tree, svars, i, subvar); ++i)
2784 bitmap_set_bit (*addresses_taken, DECL_UID (subvar));
2785 TREE_ADDRESSABLE (subvar) = 1;
2788 else
2790 bitmap_set_bit (*addresses_taken, DECL_UID (var));
2791 TREE_ADDRESSABLE (var) = 1;
2797 /* Scan the immediate_use list for VAR making sure its linked properly.
2798 Return TRUE if there is a problem and emit an error message to F. */
2800 bool
2801 verify_imm_links (FILE *f, tree var)
2803 use_operand_p ptr, prev, list;
2804 int count;
2806 gcc_assert (TREE_CODE (var) == SSA_NAME);
2808 list = &(SSA_NAME_IMM_USE_NODE (var));
2809 gcc_assert (list->use == NULL);
2811 if (list->prev == NULL)
2813 gcc_assert (list->next == NULL);
2814 return false;
2817 prev = list;
2818 count = 0;
2819 for (ptr = list->next; ptr != list; )
2821 if (prev != ptr->prev)
2822 goto error;
2824 if (ptr->use == NULL)
2825 goto error; /* 2 roots, or SAFE guard node. */
2826 else if (*(ptr->use) != var)
2827 goto error;
2829 prev = ptr;
2830 ptr = ptr->next;
2832 /* Avoid infinite loops. 50,000,000 uses probably indicates a
2833 problem. */
2834 if (count++ > 50000000)
2835 goto error;
2838 /* Verify list in the other direction. */
2839 prev = list;
2840 for (ptr = list->prev; ptr != list; )
2842 if (prev != ptr->next)
2843 goto error;
2844 prev = ptr;
2845 ptr = ptr->prev;
2846 if (count-- < 0)
2847 goto error;
2850 if (count != 0)
2851 goto error;
2853 return false;
2855 error:
2856 if (ptr->stmt && stmt_modified_p (ptr->stmt))
2858 fprintf (f, " STMT MODIFIED. - <%p> ", (void *)ptr->stmt);
2859 print_generic_stmt (f, ptr->stmt, TDF_SLIM);
2861 fprintf (f, " IMM ERROR : (use_p : tree - %p:%p)", (void *)ptr,
2862 (void *)ptr->use);
2863 print_generic_expr (f, USE_FROM_PTR (ptr), TDF_SLIM);
2864 fprintf(f, "\n");
2865 return true;
2869 /* Dump all the immediate uses to FILE. */
2871 void
2872 dump_immediate_uses_for (FILE *file, tree var)
2874 imm_use_iterator iter;
2875 use_operand_p use_p;
2877 gcc_assert (var && TREE_CODE (var) == SSA_NAME);
2879 print_generic_expr (file, var, TDF_SLIM);
2880 fprintf (file, " : -->");
2881 if (has_zero_uses (var))
2882 fprintf (file, " no uses.\n");
2883 else
2884 if (has_single_use (var))
2885 fprintf (file, " single use.\n");
2886 else
2887 fprintf (file, "%d uses.\n", num_imm_uses (var));
2889 FOR_EACH_IMM_USE_FAST (use_p, iter, var)
2891 if (use_p->stmt == NULL && use_p->use == NULL)
2892 fprintf (file, "***end of stmt iterator marker***\n");
2893 else
2894 if (!is_gimple_reg (USE_FROM_PTR (use_p)))
2895 print_generic_stmt (file, USE_STMT (use_p), TDF_VOPS|TDF_MEMSYMS);
2896 else
2897 print_generic_stmt (file, USE_STMT (use_p), TDF_SLIM);
2899 fprintf(file, "\n");
2903 /* Dump all the immediate uses to FILE. */
2905 void
2906 dump_immediate_uses (FILE *file)
2908 tree var;
2909 unsigned int x;
2911 fprintf (file, "Immediate_uses: \n\n");
2912 for (x = 1; x < num_ssa_names; x++)
2914 var = ssa_name(x);
2915 if (!var)
2916 continue;
2917 dump_immediate_uses_for (file, var);
2922 /* Dump def-use edges on stderr. */
2924 void
2925 debug_immediate_uses (void)
2927 dump_immediate_uses (stderr);
2931 /* Dump def-use edges on stderr. */
2933 void
2934 debug_immediate_uses_for (tree var)
2936 dump_immediate_uses_for (stderr, var);
2940 /* Create a new change buffer for the statement pointed by STMT_P and
2941 push the buffer into SCB_STACK. Each change buffer
2942 records state information needed to determine what changed in the
2943 statement. Mainly, this keeps track of symbols that may need to be
2944 put into SSA form, SSA name replacements and other information
2945 needed to keep the SSA form up to date. */
2947 void
2948 push_stmt_changes (tree *stmt_p)
2950 tree stmt;
2951 scb_t buf;
2953 stmt = *stmt_p;
2955 /* It makes no sense to keep track of PHI nodes. */
2956 if (TREE_CODE (stmt) == PHI_NODE)
2957 return;
2959 buf = XNEW (struct scb_d);
2960 memset (buf, 0, sizeof *buf);
2962 buf->stmt_p = stmt_p;
2964 if (stmt_references_memory_p (stmt))
2966 tree op;
2967 ssa_op_iter i;
2969 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_VUSE)
2971 tree sym = TREE_CODE (op) == SSA_NAME ? SSA_NAME_VAR (op) : op;
2972 if (buf->loads == NULL)
2973 buf->loads = BITMAP_ALLOC (NULL);
2974 bitmap_set_bit (buf->loads, DECL_UID (sym));
2977 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_VDEF)
2979 tree sym = TREE_CODE (op) == SSA_NAME ? SSA_NAME_VAR (op) : op;
2980 if (buf->stores == NULL)
2981 buf->stores = BITMAP_ALLOC (NULL);
2982 bitmap_set_bit (buf->stores, DECL_UID (sym));
2986 VEC_safe_push (scb_t, heap, scb_stack, buf);
2990 /* Given two sets S1 and S2, mark the symbols that differ in S1 and S2
2991 for renaming. The set to mark for renaming is (S1 & ~S2) | (S2 & ~S1). */
2993 static void
2994 mark_difference_for_renaming (bitmap s1, bitmap s2)
2996 if (s1 == NULL && s2 == NULL)
2997 return;
2999 if (s1 && s2 == NULL)
3000 mark_set_for_renaming (s1);
3001 else if (s1 == NULL && s2)
3002 mark_set_for_renaming (s2);
3003 else if (!bitmap_equal_p (s1, s2))
3005 bitmap t1 = BITMAP_ALLOC (NULL);
3006 bitmap t2 = BITMAP_ALLOC (NULL);
3008 bitmap_and_compl (t1, s1, s2);
3009 bitmap_and_compl (t2, s2, s1);
3010 bitmap_ior_into (t1, t2);
3011 mark_set_for_renaming (t1);
3013 BITMAP_FREE (t1);
3014 BITMAP_FREE (t2);
3019 /* Pop the top SCB from SCB_STACK and act on the differences between
3020 what was recorded by push_stmt_changes and the current state of
3021 the statement. */
3023 void
3024 pop_stmt_changes (tree *stmt_p)
3026 tree op, stmt;
3027 ssa_op_iter iter;
3028 bitmap loads, stores;
3029 scb_t buf;
3031 stmt = *stmt_p;
3033 /* It makes no sense to keep track of PHI nodes. */
3034 if (TREE_CODE (stmt) == PHI_NODE)
3035 return;
3037 buf = VEC_pop (scb_t, scb_stack);
3038 gcc_assert (stmt_p == buf->stmt_p);
3040 /* Force an operand re-scan on the statement and mark any newly
3041 exposed variables. */
3042 update_stmt (stmt);
3044 /* Determine whether any memory symbols need to be renamed. If the
3045 sets of loads and stores are different after the statement is
3046 modified, then the affected symbols need to be renamed.
3048 Note that it may be possible for the statement to not reference
3049 memory anymore, but we still need to act on the differences in
3050 the sets of symbols. */
3051 loads = stores = NULL;
3052 if (stmt_references_memory_p (stmt))
3054 tree op;
3055 ssa_op_iter i;
3057 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_VUSE)
3059 tree sym = TREE_CODE (op) == SSA_NAME ? SSA_NAME_VAR (op) : op;
3060 if (loads == NULL)
3061 loads = BITMAP_ALLOC (NULL);
3062 bitmap_set_bit (loads, DECL_UID (sym));
3065 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_VDEF)
3067 tree sym = TREE_CODE (op) == SSA_NAME ? SSA_NAME_VAR (op) : op;
3068 if (stores == NULL)
3069 stores = BITMAP_ALLOC (NULL);
3070 bitmap_set_bit (stores, DECL_UID (sym));
3074 /* If LOADS is different from BUF->LOADS, the affected
3075 symbols need to be marked for renaming. */
3076 mark_difference_for_renaming (loads, buf->loads);
3078 /* Similarly for STORES and BUF->STORES. */
3079 mark_difference_for_renaming (stores, buf->stores);
3081 /* Mark all the naked GIMPLE register operands for renaming. */
3082 FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_DEF|SSA_OP_USE)
3083 if (DECL_P (op))
3084 mark_sym_for_renaming (op);
3086 /* FIXME, need to add more finalizers here. Cleanup EH info,
3087 recompute invariants for address expressions, add
3088 SSA replacement mappings, etc. For instance, given
3089 testsuite/gcc.c-torture/compile/pr16808.c, we fold a statement of
3090 the form:
3092 # SMT.4_20 = VDEF <SMT.4_16>
3093 D.1576_11 = 1.0e+0;
3095 So, the VDEF will disappear, but instead of marking SMT.4 for
3096 renaming it would be far more efficient to establish a
3097 replacement mapping that would replace every reference of
3098 SMT.4_20 with SMT.4_16. */
3100 /* Free memory used by the buffer. */
3101 BITMAP_FREE (buf->loads);
3102 BITMAP_FREE (buf->stores);
3103 BITMAP_FREE (loads);
3104 BITMAP_FREE (stores);
3105 buf->stmt_p = NULL;
3106 free (buf);
3110 /* Discard the topmost change buffer from SCB_STACK. This is useful
3111 when the caller realized that it did not actually modified the
3112 statement. It avoids the expensive operand re-scan. */
3114 void
3115 discard_stmt_changes (tree *stmt_p)
3117 scb_t buf;
3118 tree stmt;
3120 /* It makes no sense to keep track of PHI nodes. */
3121 stmt = *stmt_p;
3122 if (TREE_CODE (stmt) == PHI_NODE)
3123 return;
3125 buf = VEC_pop (scb_t, scb_stack);
3126 gcc_assert (stmt_p == buf->stmt_p);
3128 /* Free memory used by the buffer. */
3129 BITMAP_FREE (buf->loads);
3130 BITMAP_FREE (buf->stores);
3131 buf->stmt_p = NULL;
3132 free (buf);
3136 /* Returns true if statement STMT may access memory. */
3138 bool
3139 stmt_references_memory_p (tree stmt)
3141 if (!gimple_ssa_operands (cfun)->ops_active || TREE_CODE (stmt) == PHI_NODE)
3142 return false;
3144 return stmt_ann (stmt)->references_memory;