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)
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/>. */
22 #include "coretypes.h"
27 #include "diagnostic.h"
28 #include "tree-flow.h"
29 #include "tree-inline.h"
30 #include "tree-pass.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
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 operand
74 vector for VUSE, then the new vector will also be modified such that
75 it contains 'a_5' rather than 'a'. */
78 /* Structure storing statistics on how many call clobbers we have, and
79 how many where avoided. */
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
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;
107 /* Flags to describe operand properties in helpers. */
109 /* By default, operands are loaded. */
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
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. */
180 /* Pointer to the statement being modified. */
183 /* If the statement references memory these are the sets of symbols
184 loaded and stored by the statement. */
189 typedef struct scb_d *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)
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);
225 return (u1 > u2 ? 1 : -1);
229 /* Sort the virtual operands in LIST from lowest DECL_UID to highest. */
232 operand_build_sort_virtual (VEC(tree,heap) *list)
234 int num = VEC_length (tree, list);
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);
252 /* There are 3 or more elements, call qsort. */
253 qsort (VEC_address (tree, list),
254 VEC_length (tree, list),
260 /* Return true if the SSA operands cache is active. */
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
282 Any VOPs larger than this are simply added to the largest bucket when they
286 /* Return the number of operands used in bucket BUCKET. */
289 vop_free_bucket_size (int bucket)
291 #ifdef ENABLE_CHECKING
292 gcc_assert (bucket >= 0 && bucket < NUM_VOP_FREE_BUCKETS);
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. */
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. */
311 /* Buckets 16 - NUM_VOP_FREE_BUCKETS represent 8 unit chunks. */
312 num = 14 + (num - 1) / 8;
313 if (num >= NUM_VOP_FREE_BUCKETS)
320 /* Initialize the VOP free buckets. */
323 init_vop_buckets (void)
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. */
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. */
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
354 #define OP_SIZE_2 110
355 #define OP_SIZE_3 511
357 /* Initialize the operand cache routines. */
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));
381 gimple_ssa_operands (cfun)->ssa_operand_mem_size = OP_SIZE_INIT;
385 /* Dispose of anything required by the operand routines. */
388 fini_ssa_operands (void)
390 struct ssa_operand_memory_d *ptr;
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);
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;
420 VEC_iterate (tree, gimple_ssa_operands (cfun)->mpt_table, ix, 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;
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. */
454 ssa_operand_alloc (unsigned size)
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);
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);
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 /* Fail if there is not enough space. If there are this many operands
481 required, first make sure there isn't a different problem causing this
482 many operands. If the decision is that this is OK, then we can
483 specially allocate a buffer just for this request. */
484 gcc_assert (size <= gimple_ssa_operands (cfun)->ssa_operand_mem_size);
486 ptr = (struct ssa_operand_memory_d *)
487 ggc_alloc (sizeof (struct ssa_operand_memory_d)
488 + gimple_ssa_operands (cfun)->ssa_operand_mem_size - 1);
489 ptr->next = gimple_ssa_operands (cfun)->operand_memory;
490 gimple_ssa_operands (cfun)->operand_memory = ptr;
491 gimple_ssa_operands (cfun)->operand_memory_index = 0;
493 ptr = &(gimple_ssa_operands (cfun)->operand_memory
494 ->mem[gimple_ssa_operands (cfun)->operand_memory_index]);
495 gimple_ssa_operands (cfun)->operand_memory_index += size;
500 /* Allocate a DEF operand. */
502 static inline struct def_optype_d *
505 struct def_optype_d *ret;
506 if (gimple_ssa_operands (cfun)->free_defs)
508 ret = gimple_ssa_operands (cfun)->free_defs;
509 gimple_ssa_operands (cfun)->free_defs
510 = gimple_ssa_operands (cfun)->free_defs->next;
513 ret = (struct def_optype_d *)
514 ssa_operand_alloc (sizeof (struct def_optype_d));
519 /* Allocate a USE operand. */
521 static inline struct use_optype_d *
524 struct use_optype_d *ret;
525 if (gimple_ssa_operands (cfun)->free_uses)
527 ret = gimple_ssa_operands (cfun)->free_uses;
528 gimple_ssa_operands (cfun)->free_uses
529 = gimple_ssa_operands (cfun)->free_uses->next;
532 ret = (struct use_optype_d *)
533 ssa_operand_alloc (sizeof (struct use_optype_d));
538 /* Allocate a vop with NUM elements. */
540 static inline struct voptype_d *
543 struct voptype_d *ret = NULL;
546 int bucket = vop_free_bucket_index (num);
549 /* If there is a free operand, use it. */
550 if (gimple_ssa_operands (cfun)->vop_free_buckets[bucket] != NULL)
552 ret = gimple_ssa_operands (cfun)->vop_free_buckets[bucket];
553 gimple_ssa_operands (cfun)->vop_free_buckets[bucket] =
554 gimple_ssa_operands (cfun)->vop_free_buckets[bucket]->next;
557 alloc_size = vop_free_bucket_size(bucket);
563 ret = (struct voptype_d *)ssa_operand_alloc (
564 sizeof (struct voptype_d) + (alloc_size - 1) * sizeof (vuse_element_t));
566 VUSE_VECT_NUM_ELEM (ret->usev) = num;
571 /* This routine makes sure that PTR is in an immediate use list, and makes
572 sure the stmt pointer is set to the current stmt. */
575 set_virtual_use_link (use_operand_p ptr, tree stmt)
577 /* fold_stmt may have changed the stmt pointers. */
578 if (ptr->stmt != stmt)
581 /* If this use isn't in a list, add it to the correct list. */
583 link_imm_use (ptr, *(ptr->use));
587 /* Adds OP to the list of defs after LAST. */
589 static inline def_optype_p
590 add_def_op (tree *op, def_optype_p last)
592 def_optype_p new_def;
594 new_def = alloc_def ();
595 DEF_OP_PTR (new_def) = op;
596 last->next = new_def;
597 new_def->next = NULL;
602 /* Adds OP to the list of uses of statement STMT after LAST. */
604 static inline use_optype_p
605 add_use_op (tree stmt, tree *op, use_optype_p last)
607 use_optype_p new_use;
609 new_use = alloc_use ();
610 USE_OP_PTR (new_use)->use = op;
611 link_imm_use_stmt (USE_OP_PTR (new_use), *op, stmt);
612 last->next = new_use;
613 new_use->next = NULL;
618 /* Return a virtual op pointer with NUM elements which are all initialized to OP
619 and are linked into the immediate uses for STMT. The new vop is appended
622 static inline voptype_p
623 add_vop (tree stmt, tree op, int num, voptype_p prev)
628 new_vop = alloc_vop (num);
629 for (x = 0; x < num; x++)
631 VUSE_OP_PTR (new_vop, x)->prev = NULL;
632 SET_VUSE_OP (new_vop, x, op);
633 VUSE_OP_PTR (new_vop, x)->use = &new_vop->usev.uses[x].use_var;
634 link_imm_use_stmt (VUSE_OP_PTR (new_vop, x),
635 new_vop->usev.uses[x].use_var, stmt);
639 prev->next = new_vop;
640 new_vop->next = NULL;
645 /* Adds OP to the list of vuses of statement STMT after LAST, and moves
646 LAST to the new element. */
648 static inline voptype_p
649 add_vuse_op (tree stmt, tree op, int num, voptype_p last)
651 voptype_p new_vop = add_vop (stmt, op, num, last);
652 VDEF_RESULT (new_vop) = NULL_TREE;
657 /* Adds OP to the list of vdefs of statement STMT after LAST, and moves
658 LAST to the new element. */
660 static inline voptype_p
661 add_vdef_op (tree stmt, tree op, int num, voptype_p last)
663 voptype_p new_vop = add_vop (stmt, op, num, last);
664 VDEF_RESULT (new_vop) = op;
669 /* Takes elements from build_defs and turns them into def operands of STMT.
670 TODO -- Make build_defs VEC of tree *. */
673 finalize_ssa_defs (tree stmt)
676 struct def_optype_d new_list;
677 def_optype_p old_ops, last;
678 unsigned int num = VEC_length (tree, build_defs);
680 /* There should only be a single real definition per assignment. */
681 gcc_assert ((stmt && TREE_CODE (stmt) != GIMPLE_MODIFY_STMT) || num <= 1);
683 new_list.next = NULL;
686 old_ops = DEF_OPS (stmt);
690 /* Check for the common case of 1 def that hasn't changed. */
691 if (old_ops && old_ops->next == NULL && num == 1
692 && (tree *) VEC_index (tree, build_defs, 0) == DEF_OP_PTR (old_ops))
695 /* If there is anything in the old list, free it. */
698 old_ops->next = gimple_ssa_operands (cfun)->free_defs;
699 gimple_ssa_operands (cfun)->free_defs = old_ops;
702 /* If there is anything remaining in the build_defs list, simply emit it. */
703 for ( ; new_i < num; new_i++)
704 last = add_def_op ((tree *) VEC_index (tree, build_defs, new_i), last);
706 /* Now set the stmt's operands. */
707 DEF_OPS (stmt) = new_list.next;
709 #ifdef ENABLE_CHECKING
713 for (ptr = DEF_OPS (stmt); ptr; ptr = ptr->next)
716 gcc_assert (x == num);
722 /* Takes elements from build_uses and turns them into use operands of STMT.
723 TODO -- Make build_uses VEC of tree *. */
726 finalize_ssa_uses (tree stmt)
729 struct use_optype_d new_list;
730 use_optype_p old_ops, ptr, last;
732 #ifdef ENABLE_CHECKING
735 unsigned num = VEC_length (tree, build_uses);
737 /* If the pointer to the operand is the statement itself, something is
738 wrong. It means that we are pointing to a local variable (the
739 initial call to update_stmt_operands does not pass a pointer to a
741 for (x = 0; x < num; x++)
742 gcc_assert (*((tree *)VEC_index (tree, build_uses, x)) != stmt);
746 new_list.next = NULL;
749 old_ops = USE_OPS (stmt);
751 /* If there is anything in the old list, free it. */
754 for (ptr = old_ops; ptr; ptr = ptr->next)
755 delink_imm_use (USE_OP_PTR (ptr));
756 old_ops->next = gimple_ssa_operands (cfun)->free_uses;
757 gimple_ssa_operands (cfun)->free_uses = old_ops;
760 /* Now create nodes for all the new nodes. */
761 for (new_i = 0; new_i < VEC_length (tree, build_uses); new_i++)
762 last = add_use_op (stmt,
763 (tree *) VEC_index (tree, build_uses, new_i),
766 /* Now set the stmt's operands. */
767 USE_OPS (stmt) = new_list.next;
769 #ifdef ENABLE_CHECKING
772 for (ptr = USE_OPS (stmt); ptr; ptr = ptr->next)
775 gcc_assert (x == VEC_length (tree, build_uses));
781 /* Takes elements from BUILD_VDEFS and turns them into vdef operands of
782 STMT. FIXME, for now VDEF operators should have a single operand
786 finalize_ssa_vdefs (tree stmt)
789 struct voptype_d new_list;
790 voptype_p old_ops, ptr, last;
791 stmt_ann_t ann = stmt_ann (stmt);
793 /* Set the symbols referenced by STMT. */
794 if (!bitmap_empty_p (build_stores))
796 if (ann->operands.stores == NULL)
797 ann->operands.stores = BITMAP_ALLOC (&operands_bitmap_obstack);
799 bitmap_copy (ann->operands.stores, build_stores);
802 BITMAP_FREE (ann->operands.stores);
804 /* If aliases have not been computed, do not instantiate a virtual
805 operator on STMT. Initially, we only compute the SSA form on
806 GIMPLE registers. The virtual SSA form is only computed after
807 alias analysis, so virtual operators will remain unrenamed and
808 the verifier will complain. However, alias analysis needs to
809 access symbol load/store information, so we need to compute
811 if (!gimple_aliases_computed_p (cfun))
814 new_list.next = NULL;
817 old_ops = VDEF_OPS (stmt);
819 while (old_ops && new_i < VEC_length (tree, build_vdefs))
821 tree op = VEC_index (tree, build_vdefs, new_i);
822 unsigned new_uid = get_name_decl (op);
823 unsigned old_uid = get_name_decl (VDEF_RESULT (old_ops));
825 /* FIXME, for now each VDEF operator should have at most one
826 operand in their RHS. */
827 gcc_assert (VDEF_NUM (old_ops) == 1);
829 if (old_uid == new_uid)
831 /* If the symbols are the same, reuse the existing operand. */
832 last->next = old_ops;
834 old_ops = old_ops->next;
836 set_virtual_use_link (VDEF_OP_PTR (last, 0), stmt);
839 else if (old_uid < new_uid)
841 /* If old is less than new, old goes to the free list. */
843 delink_imm_use (VDEF_OP_PTR (old_ops, 0));
844 next = old_ops->next;
845 add_vop_to_freelist (old_ops);
850 /* This is a new operand. */
851 last = add_vdef_op (stmt, op, 1, last);
856 /* If there is anything remaining in BUILD_VDEFS, simply emit it. */
857 for ( ; new_i < VEC_length (tree, build_vdefs); new_i++)
858 last = add_vdef_op (stmt, VEC_index (tree, build_vdefs, new_i), 1, last);
860 /* If there is anything in the old list, free it. */
863 for (ptr = old_ops; ptr; ptr = last)
866 delink_imm_use (VDEF_OP_PTR (ptr, 0));
867 add_vop_to_freelist (ptr);
871 /* Now set STMT's operands. */
872 VDEF_OPS (stmt) = new_list.next;
874 #ifdef ENABLE_CHECKING
877 for (ptr = VDEF_OPS (stmt); ptr; ptr = ptr->next)
880 gcc_assert (x == VEC_length (tree, build_vdefs));
886 /* Takes elements from BUILD_VUSES and turns them into VUSE operands of
890 finalize_ssa_vuse_ops (tree stmt)
892 unsigned new_i, old_i;
893 voptype_p old_ops, last;
894 VEC(tree,heap) *new_ops;
897 /* Set the symbols referenced by STMT. */
898 ann = stmt_ann (stmt);
899 if (!bitmap_empty_p (build_loads))
901 if (ann->operands.loads == NULL)
902 ann->operands.loads = BITMAP_ALLOC (&operands_bitmap_obstack);
904 bitmap_copy (ann->operands.loads, build_loads);
907 BITMAP_FREE (ann->operands.loads);
909 /* If aliases have not been computed, do not instantiate a virtual
910 operator on STMT. Initially, we only compute the SSA form on
911 GIMPLE registers. The virtual SSA form is only computed after
912 alias analysis, so virtual operators will remain unrenamed and
913 the verifier will complain. However, alias analysis needs to
914 access symbol load/store information, so we need to compute
916 if (!gimple_aliases_computed_p (cfun))
919 /* STMT should have at most one VUSE operator. */
920 old_ops = VUSE_OPS (stmt);
921 gcc_assert (old_ops == NULL || old_ops->next == NULL);
926 && old_i < VUSE_NUM (old_ops)
927 && new_i < VEC_length (tree, build_vuses))
929 tree new_op = VEC_index (tree, build_vuses, new_i);
930 tree old_op = VUSE_OP (old_ops, old_i);
931 unsigned new_uid = get_name_decl (new_op);
932 unsigned old_uid = get_name_decl (old_op);
934 if (old_uid == new_uid)
936 /* If the symbols are the same, reuse the existing operand. */
937 VEC_safe_push (tree, heap, new_ops, old_op);
941 else if (old_uid < new_uid)
943 /* If OLD_UID is less than NEW_UID, the old operand has
944 disappeared, skip to the next old operand. */
949 /* This is a new operand. */
950 VEC_safe_push (tree, heap, new_ops, new_op);
955 /* If there is anything remaining in the build_vuses list, simply emit it. */
956 for ( ; new_i < VEC_length (tree, build_vuses); new_i++)
957 VEC_safe_push (tree, heap, new_ops, VEC_index (tree, build_vuses, new_i));
959 /* If there is anything in the old list, free it. */
962 for (old_i = 0; old_i < VUSE_NUM (old_ops); old_i++)
963 delink_imm_use (VUSE_OP_PTR (old_ops, old_i));
964 add_vop_to_freelist (old_ops);
965 VUSE_OPS (stmt) = NULL;
968 /* If there are any operands, instantiate a VUSE operator for STMT. */
974 last = add_vuse_op (stmt, NULL, VEC_length (tree, new_ops), NULL);
976 for (i = 0; VEC_iterate (tree, new_ops, i, op); i++)
977 SET_USE (VUSE_OP_PTR (last, (int) i), op);
979 VUSE_OPS (stmt) = last;
980 VEC_free (tree, heap, new_ops);
983 #ifdef ENABLE_CHECKING
989 gcc_assert (VUSE_OPS (stmt)->next == NULL);
990 x = VUSE_NUM (VUSE_OPS (stmt));
995 gcc_assert (x == VEC_length (tree, build_vuses));
1000 /* Return a new VUSE operand vector for STMT. */
1003 finalize_ssa_vuses (tree stmt)
1005 unsigned num, num_vdefs;
1006 unsigned vuse_index;
1008 /* Remove superfluous VUSE operands. If the statement already has a
1009 VDEF operator for a variable 'a', then a VUSE for 'a' is not
1010 needed because VDEFs imply a VUSE of the variable. For instance,
1011 suppose that variable 'a' is pointed-to by p and q:
1017 The VUSE <a_2> is superfluous because it is implied by the
1019 num = VEC_length (tree, build_vuses);
1020 num_vdefs = VEC_length (tree, build_vdefs);
1022 if (num > 0 && num_vdefs > 0)
1023 for (vuse_index = 0; vuse_index < VEC_length (tree, build_vuses); )
1026 vuse = VEC_index (tree, build_vuses, vuse_index);
1027 if (TREE_CODE (vuse) != SSA_NAME)
1029 var_ann_t ann = var_ann (vuse);
1030 ann->in_vuse_list = 0;
1031 if (ann->in_vdef_list)
1033 VEC_ordered_remove (tree, build_vuses, vuse_index);
1040 finalize_ssa_vuse_ops (stmt);
1044 /* Clear the in_list bits and empty the build array for VDEFs and
1048 cleanup_build_arrays (void)
1053 for (i = 0; VEC_iterate (tree, build_vdefs, i, t); i++)
1054 if (TREE_CODE (t) != SSA_NAME)
1055 var_ann (t)->in_vdef_list = false;
1057 for (i = 0; VEC_iterate (tree, build_vuses, i, t); i++)
1058 if (TREE_CODE (t) != SSA_NAME)
1059 var_ann (t)->in_vuse_list = false;
1061 VEC_truncate (tree, build_vdefs, 0);
1062 VEC_truncate (tree, build_vuses, 0);
1063 VEC_truncate (tree, build_defs, 0);
1064 VEC_truncate (tree, build_uses, 0);
1065 bitmap_clear (build_loads);
1066 bitmap_clear (build_stores);
1070 /* Finalize all the build vectors, fill the new ones into INFO. */
1073 finalize_ssa_stmt_operands (tree stmt)
1075 finalize_ssa_defs (stmt);
1076 finalize_ssa_uses (stmt);
1077 finalize_ssa_vdefs (stmt);
1078 finalize_ssa_vuses (stmt);
1079 cleanup_build_arrays ();
1083 /* Start the process of building up operands vectors in INFO. */
1086 start_ssa_stmt_operands (void)
1088 gcc_assert (VEC_length (tree, build_defs) == 0);
1089 gcc_assert (VEC_length (tree, build_uses) == 0);
1090 gcc_assert (VEC_length (tree, build_vuses) == 0);
1091 gcc_assert (VEC_length (tree, build_vdefs) == 0);
1092 gcc_assert (bitmap_empty_p (build_loads));
1093 gcc_assert (bitmap_empty_p (build_stores));
1097 /* Add DEF_P to the list of pointers to operands. */
1100 append_def (tree *def_p)
1102 VEC_safe_push (tree, heap, build_defs, (tree) def_p);
1106 /* Add USE_P to the list of pointers to operands. */
1109 append_use (tree *use_p)
1111 VEC_safe_push (tree, heap, build_uses, (tree) use_p);
1115 /* Add VAR to the set of variables that require a VDEF operator. */
1118 append_vdef (tree var)
1122 if (TREE_CODE (var) != SSA_NAME)
1127 /* If VAR belongs to a memory partition, use it instead of VAR. */
1128 mpt = memory_partition (var);
1132 /* Don't allow duplicate entries. */
1133 ann = get_var_ann (var);
1134 if (ann->in_vdef_list)
1137 ann->in_vdef_list = true;
1141 sym = SSA_NAME_VAR (var);
1143 VEC_safe_push (tree, heap, build_vdefs, var);
1144 bitmap_set_bit (build_stores, DECL_UID (sym));
1148 /* Add VAR to the set of variables that require a VUSE operator. */
1151 append_vuse (tree var)
1155 if (TREE_CODE (var) != SSA_NAME)
1160 /* If VAR belongs to a memory partition, use it instead of VAR. */
1161 mpt = memory_partition (var);
1165 /* Don't allow duplicate entries. */
1166 ann = get_var_ann (var);
1167 if (ann->in_vuse_list)
1169 else if (ann->in_vdef_list)
1171 /* We don't want a vuse if we already have a vdef, but we must
1172 still put this in build_loads. */
1173 bitmap_set_bit (build_loads, DECL_UID (var));
1177 ann->in_vuse_list = true;
1181 sym = SSA_NAME_VAR (var);
1183 VEC_safe_push (tree, heap, build_vuses, var);
1184 bitmap_set_bit (build_loads, DECL_UID (sym));
1188 /* REF is a tree that contains the entire pointer dereference
1189 expression, if available, or NULL otherwise. ALIAS is the variable
1190 we are asking if REF can access. OFFSET and SIZE come from the
1191 memory access expression that generated this virtual operand.
1193 XXX: We should handle the NO_ALIAS attributes here. */
1196 access_can_touch_variable (tree ref, tree alias, HOST_WIDE_INT offset,
1199 bool offsetgtz = offset > 0;
1200 unsigned HOST_WIDE_INT uoffset = (unsigned HOST_WIDE_INT) offset;
1201 tree base = ref ? get_base_address (ref) : NULL;
1203 /* If ALIAS is .GLOBAL_VAR then the memory reference REF must be
1204 using a call-clobbered memory tag. By definition, call-clobbered
1205 memory tags can always touch .GLOBAL_VAR. */
1206 if (alias == gimple_global_var (cfun))
1209 /* If ref is a TARGET_MEM_REF, just return true, as we can't really
1210 disambiguate them right now. */
1211 if (ref && TREE_CODE (ref) == TARGET_MEM_REF)
1214 /* If ALIAS is an SFT, it can't be touched if the offset
1215 and size of the access is not overlapping with the SFT offset and
1216 size. This is only true if we are accessing through a pointer
1217 to a type that is the same as SFT_PARENT_VAR. Otherwise, we may
1218 be accessing through a pointer to some substruct of the
1219 structure, and if we try to prune there, we will have the wrong
1220 offset, and get the wrong answer.
1221 i.e., we can't prune without more work if we have something like
1227 const char *byte_op;
1235 foo = &targetm.asm_out.aligned_op;
1238 SFT.1, which represents hi, will have SFT_OFFSET=32 because in
1239 terms of SFT_PARENT_VAR, that is where it is.
1240 However, the access through the foo pointer will be at offset 0. */
1242 && TREE_CODE (alias) == STRUCT_FIELD_TAG
1244 && TREE_TYPE (base) == TREE_TYPE (SFT_PARENT_VAR (alias))
1245 && !overlap_subvar (offset, size, alias, NULL))
1247 #ifdef ACCESS_DEBUGGING
1248 fprintf (stderr, "Access to ");
1249 print_generic_expr (stderr, ref, 0);
1250 fprintf (stderr, " may not touch ");
1251 print_generic_expr (stderr, alias, 0);
1252 fprintf (stderr, " in function %s\n", get_name (current_function_decl));
1257 /* Without strict aliasing, it is impossible for a component access
1258 through a pointer to touch a random variable, unless that
1259 variable *is* a structure or a pointer.
1261 That is, given p->c, and some random global variable b,
1262 there is no legal way that p->c could be an access to b.
1264 Without strict aliasing on, we consider it legal to do something
1267 struct foos { int l; };
1269 static struct foos *getfoo(void);
1272 struct foos *f = getfoo();
1279 static struct foos *getfoo(void)
1280 { return (struct foos *)&foo; }
1282 (taken from 20000623-1.c)
1284 The docs also say/imply that access through union pointers
1285 is legal (but *not* if you take the address of the union member,
1286 i.e. the inverse), such that you can do
1296 U *pretmp = (U*)&rv;
1300 To implement this, we just punt on accesses through union
1303 Another case we have to allow is accessing a variable
1304 through an array access at offset zero. This happens from
1305 code generated by the fortran frontend like
1307 char[1:1] & my_char_ref;
1309 my_char_ref_1 = (char[1:1] &) &my_char;
1310 D.874_2 = (*my_char_ref_1)[1]{lb: 1 sz: 1};
1313 && flag_strict_aliasing
1314 && TREE_CODE (ref) != INDIRECT_REF
1317 && (TREE_CODE (base) != INDIRECT_REF
1318 || TREE_CODE (TREE_TYPE (base)) != UNION_TYPE)
1319 && (TREE_CODE (base) != INDIRECT_REF
1320 || TREE_CODE (ref) != ARRAY_REF
1322 || (DECL_SIZE (alias)
1323 && TREE_CODE (DECL_SIZE (alias)) == INTEGER_CST
1325 && (unsigned HOST_WIDE_INT)size
1326 != TREE_INT_CST_LOW (DECL_SIZE (alias))))
1327 && !AGGREGATE_TYPE_P (TREE_TYPE (alias))
1328 && TREE_CODE (TREE_TYPE (alias)) != COMPLEX_TYPE
1329 && !var_ann (alias)->is_heapvar
1330 /* When the struct has may_alias attached to it, we need not to
1332 && get_alias_set (base))
1334 #ifdef ACCESS_DEBUGGING
1335 fprintf (stderr, "Access to ");
1336 print_generic_expr (stderr, ref, 0);
1337 fprintf (stderr, " may not touch ");
1338 print_generic_expr (stderr, alias, 0);
1339 fprintf (stderr, " in function %s\n", get_name (current_function_decl));
1344 /* If the offset of the access is greater than the size of one of
1345 the possible aliases, it can't be touching that alias, because it
1346 would be past the end of the structure. */
1348 && flag_strict_aliasing
1349 && TREE_CODE (ref) != INDIRECT_REF
1351 && !POINTER_TYPE_P (TREE_TYPE (alias))
1353 && DECL_SIZE (alias)
1354 && TREE_CODE (DECL_SIZE (alias)) == INTEGER_CST
1355 && uoffset > TREE_INT_CST_LOW (DECL_SIZE (alias)))
1357 #ifdef ACCESS_DEBUGGING
1358 fprintf (stderr, "Access to ");
1359 print_generic_expr (stderr, ref, 0);
1360 fprintf (stderr, " may not touch ");
1361 print_generic_expr (stderr, alias, 0);
1362 fprintf (stderr, " in function %s\n", get_name (current_function_decl));
1370 /* Add the actual variables FULL_REF can access, given a member of
1371 full_ref's points-to set VAR, where FULL_REF is an access of SIZE at
1372 OFFSET from var. IS_CALL_SITE is true if this is a call, and IS_DEF
1373 is true if this is supposed to be a vdef, and false if this should
1376 The real purpose of this function is to take a points-to set for a
1377 pointer to a structure, say
1382 } foo, *foop = &foo;
1384 and discover which variables an access, such as foop->b, can alias.
1386 This is necessary because foop only actually points to foo's first
1387 member, so that is all the points-to set contains. However, an access
1388 to foop->a may be touching some single SFT if we have created some
1389 SFT's for a structure. */
1392 add_vars_for_offset (tree var,
1393 unsigned HOST_WIDE_INT offset, unsigned HOST_WIDE_INT size,
1401 /* Adjust offset by the pointed-to location. */
1402 offset += SFT_OFFSET (var);
1404 /* Add all subvars of var that overlap with the access.
1405 Binary search for the first relevant SFT. */
1406 sv = get_subvars_for_var (SFT_PARENT_VAR (var));
1407 if (!get_first_overlapping_subvar (sv, offset, size, &i))
1410 for (; VEC_iterate (tree, sv, i, subvar); ++i)
1412 if (size <= SFT_OFFSET (subvar) - offset)
1416 append_vdef (subvar);
1418 append_vuse (subvar);
1425 /* Add VAR to the virtual operands array. FLAGS is as in
1426 get_expr_operands. FULL_REF is a tree that contains the entire
1427 pointer dereference expression, if available, or NULL otherwise.
1428 OFFSET and SIZE come from the memory access expression that
1429 generated this virtual operand. IS_CALL_SITE is true if the
1430 affected statement is a call site. */
1433 add_virtual_operand (tree var, stmt_ann_t s_ann, int flags,
1434 tree full_ref, HOST_WIDE_INT offset,
1435 HOST_WIDE_INT size, bool is_call_site)
1437 bitmap aliases = NULL;
1441 sym = (TREE_CODE (var) == SSA_NAME ? SSA_NAME_VAR (var) : var);
1442 v_ann = var_ann (sym);
1444 /* Mark the statement as having memory operands. */
1445 s_ann->references_memory = true;
1447 /* If the variable cannot be modified and this is a VDEF change
1448 it into a VUSE. This happens when read-only variables are marked
1449 call-clobbered and/or aliased to writable variables. So we only
1450 check that this only happens on non-specific stores.
1452 Note that if this is a specific store, i.e. associated with a
1453 GIMPLE_MODIFY_STMT, then we can't suppress the VDEF, lest we run
1454 into validation problems.
1456 This can happen when programs cast away const, leaving us with a
1457 store to read-only memory. If the statement is actually executed
1458 at runtime, then the program is ill formed. If the statement is
1459 not executed then all is well. At the very least, we cannot ICE. */
1460 if ((flags & opf_implicit) && unmodifiable_var_p (var))
1463 /* The variable is not a GIMPLE register. Add it (or its aliases) to
1464 virtual operands, unless the caller has specifically requested
1465 not to add virtual operands (used when adding operands inside an
1466 ADDR_EXPR expression). */
1467 if (flags & opf_no_vops)
1471 aliases = MTAG_ALIASES (var);
1473 if (aliases == NULL)
1475 if (!gimple_aliases_computed_p (cfun)
1476 && (flags & opf_def))
1477 s_ann->has_volatile_ops = true;
1479 /* The variable is not aliased or it is an alias tag. */
1480 if (flags & opf_def)
1489 bool none_added = true;
1491 /* The variable is aliased. Add its aliases to the virtual
1493 gcc_assert (!bitmap_empty_p (aliases));
1495 EXECUTE_IF_SET_IN_BITMAP (aliases, 0, i, bi)
1497 tree al = referenced_var (i);
1499 /* For SFTs we have to consider all subvariables of the parent var
1500 if it is a potential points-to location. */
1501 if (TREE_CODE (al) == STRUCT_FIELD_TAG
1502 && TREE_CODE (var) == NAME_MEMORY_TAG)
1503 none_added &= !add_vars_for_offset (al, offset, size,
1507 /* Call-clobbered tags may have non-call-clobbered
1508 symbols in their alias sets. Ignore them if we are
1509 adding VOPs for a call site. */
1510 if (is_call_site && !is_call_clobbered (al))
1513 /* If we do not know the full reference tree or if the access is
1514 unspecified [0, -1], we cannot prune it. Otherwise try doing
1515 so using access_can_touch_variable. */
1517 && !(offset == 0 && size == -1)
1518 && !access_can_touch_variable (full_ref, al, offset, size))
1521 if (flags & opf_def)
1529 if (flags & opf_def)
1531 /* If the variable is also an alias tag, add a virtual
1532 operand for it, otherwise we will miss representing
1533 references to the members of the variable's alias set.
1534 This fixes the bug in gcc.c-torture/execute/20020503-1.c.
1536 It is also necessary to add bare defs on clobbers for
1537 SMT's, so that bare SMT uses caused by pruning all the
1538 aliases will link up properly with calls. In order to
1539 keep the number of these bare defs we add down to the
1540 minimum necessary, we keep track of which SMT's were used
1541 alone in statement vdefs or VUSEs. */
1543 || (TREE_CODE (var) == SYMBOL_MEMORY_TAG
1549 /* Even if no aliases have been added, we still need to
1550 establish def-use and use-def chains, lest
1551 transformations think that this is not a memory
1552 reference. For an example of this scenario, see
1553 testsuite/g++.dg/opt/cleanup1.C. */
1561 /* Add *VAR_P to the appropriate operand array for S_ANN. FLAGS is as in
1562 get_expr_operands. If *VAR_P is a GIMPLE register, it will be added to
1563 the statement's real operands, otherwise it is added to virtual
1567 add_stmt_operand (tree *var_p, stmt_ann_t s_ann, int flags)
1572 gcc_assert (SSA_VAR_P (*var_p) && s_ann);
1575 sym = (TREE_CODE (var) == SSA_NAME ? SSA_NAME_VAR (var) : var);
1576 v_ann = var_ann (sym);
1578 /* Mark statements with volatile operands. */
1579 if (TREE_THIS_VOLATILE (sym))
1580 s_ann->has_volatile_ops = true;
1582 if (is_gimple_reg (sym))
1584 /* The variable is a GIMPLE register. Add it to real operands. */
1585 if (flags & opf_def)
1591 add_virtual_operand (var, s_ann, flags, NULL_TREE, 0, -1, false);
1594 /* Subroutine of get_indirect_ref_operands. ADDR is the address
1595 that is dereferenced, the meaning of the rest of the arguments
1596 is the same as in get_indirect_ref_operands. */
1599 get_addr_dereference_operands (tree stmt, tree *addr, int flags,
1601 HOST_WIDE_INT offset, HOST_WIDE_INT size,
1602 bool recurse_on_base)
1605 stmt_ann_t s_ann = stmt_ann (stmt);
1607 s_ann->references_memory = true;
1609 if (SSA_VAR_P (ptr))
1611 struct ptr_info_def *pi = NULL;
1613 /* If PTR has flow-sensitive points-to information, use it. */
1614 if (TREE_CODE (ptr) == SSA_NAME
1615 && (pi = SSA_NAME_PTR_INFO (ptr)) != NULL
1616 && pi->name_mem_tag)
1618 /* PTR has its own memory tag. Use it. */
1619 add_virtual_operand (pi->name_mem_tag, s_ann, flags,
1620 full_ref, offset, size, false);
1624 /* If PTR is not an SSA_NAME or it doesn't have a name
1625 tag, use its symbol memory tag. */
1628 /* If we are emitting debugging dumps, display a warning if
1629 PTR is an SSA_NAME with no flow-sensitive alias
1630 information. That means that we may need to compute
1633 && TREE_CODE (ptr) == SSA_NAME
1637 "NOTE: no flow-sensitive alias info for ");
1638 print_generic_expr (dump_file, ptr, dump_flags);
1639 fprintf (dump_file, " in ");
1640 print_generic_stmt (dump_file, stmt, dump_flags);
1643 if (TREE_CODE (ptr) == SSA_NAME)
1644 ptr = SSA_NAME_VAR (ptr);
1645 v_ann = var_ann (ptr);
1647 /* If we don't know what this pointer points to then we have
1648 to make sure to not prune virtual operands based on offset
1650 if (v_ann->symbol_mem_tag)
1651 add_virtual_operand (v_ann->symbol_mem_tag, s_ann, flags,
1652 full_ref, 0, -1, false);
1654 /* Aliasing information is missing; mark statement as
1655 volatile so we won't optimize it out too actively. */
1656 else if (!gimple_aliases_computed_p (cfun)
1657 && (flags & opf_def))
1658 s_ann->has_volatile_ops = true;
1661 else if (TREE_CODE (ptr) == INTEGER_CST)
1663 /* If a constant is used as a pointer, we can't generate a real
1664 operand for it but we mark the statement volatile to prevent
1665 optimizations from messing things up. */
1666 s_ann->has_volatile_ops = true;
1671 /* Ok, this isn't even is_gimple_min_invariant. Something's broke. */
1675 /* If requested, add a USE operand for the base pointer. */
1676 if (recurse_on_base)
1677 get_expr_operands (stmt, addr, opf_use);
1680 /* A subroutine of get_expr_operands to handle INDIRECT_REF,
1681 ALIGN_INDIRECT_REF and MISALIGNED_INDIRECT_REF.
1683 STMT is the statement being processed, EXPR is the INDIRECT_REF
1686 FLAGS is as in get_expr_operands.
1688 FULL_REF contains the full pointer dereference expression, if we
1689 have it, or NULL otherwise.
1691 OFFSET and SIZE are the location of the access inside the
1692 dereferenced pointer, if known.
1694 RECURSE_ON_BASE should be set to true if we want to continue
1695 calling get_expr_operands on the base pointer, and false if
1696 something else will do it for us. */
1699 get_indirect_ref_operands (tree stmt, tree expr, int flags,
1701 HOST_WIDE_INT offset, HOST_WIDE_INT size,
1702 bool recurse_on_base)
1704 tree *pptr = &TREE_OPERAND (expr, 0);
1705 stmt_ann_t s_ann = stmt_ann (stmt);
1707 if (TREE_THIS_VOLATILE (expr))
1708 s_ann->has_volatile_ops = true;
1710 get_addr_dereference_operands (stmt, pptr, flags, full_ref,
1711 offset, size, recurse_on_base);
1714 /* A subroutine of get_expr_operands to handle TARGET_MEM_REF. */
1717 get_tmr_operands (tree stmt, tree expr, int flags)
1720 stmt_ann_t s_ann = stmt_ann (stmt);
1722 /* This statement references memory. */
1723 s_ann->references_memory = 1;
1725 /* First record the real operands. */
1726 get_expr_operands (stmt, &TMR_BASE (expr), opf_use);
1727 get_expr_operands (stmt, &TMR_INDEX (expr), opf_use);
1729 if (TMR_SYMBOL (expr))
1730 add_to_addressable_set (TMR_SYMBOL (expr), &s_ann->addresses_taken);
1732 tag = TMR_TAG (expr);
1735 /* Something weird, so ensure that we will be careful. */
1736 s_ann->has_volatile_ops = true;
1741 get_expr_operands (stmt, &tag, flags);
1745 add_virtual_operand (tag, s_ann, flags, expr, 0, -1, false);
1749 /* Add clobbering definitions for .GLOBAL_VAR or for each of the call
1750 clobbered variables in the function. */
1753 add_call_clobber_ops (tree stmt, tree callee)
1757 stmt_ann_t s_ann = stmt_ann (stmt);
1758 bitmap not_read_b, not_written_b;
1760 /* If we created .GLOBAL_VAR earlier, just use it. */
1761 if (gimple_global_var (cfun))
1763 tree var = gimple_global_var (cfun);
1764 add_virtual_operand (var, s_ann, opf_def, NULL, 0, -1, true);
1768 /* Get info for local and module level statics. There is a bit
1769 set for each static if the call being processed does not read
1770 or write that variable. */
1771 not_read_b = callee ? ipa_reference_get_not_read_global (callee) : NULL;
1772 not_written_b = callee ? ipa_reference_get_not_written_global (callee) : NULL;
1774 /* Add a VDEF operand for every call clobbered variable. */
1775 EXECUTE_IF_SET_IN_BITMAP (gimple_call_clobbered_vars (cfun), 0, u, bi)
1777 tree var = referenced_var_lookup (u);
1778 unsigned int escape_mask = var_ann (var)->escape_mask;
1779 tree real_var = var;
1783 /* Not read and not written are computed on regular vars, not
1784 subvars, so look at the parent var if this is an SFT. */
1785 if (TREE_CODE (var) == STRUCT_FIELD_TAG)
1786 real_var = SFT_PARENT_VAR (var);
1788 not_read = not_read_b
1789 ? bitmap_bit_p (not_read_b, DECL_UID (real_var))
1792 not_written = not_written_b
1793 ? bitmap_bit_p (not_written_b, DECL_UID (real_var))
1795 gcc_assert (!unmodifiable_var_p (var));
1797 clobber_stats.clobbered_vars++;
1799 /* See if this variable is really clobbered by this function. */
1801 /* Trivial case: Things escaping only to pure/const are not
1802 clobbered by non-pure-const, and only read by pure/const. */
1803 if ((escape_mask & ~(ESCAPE_TO_PURE_CONST)) == 0)
1805 tree call = get_call_expr_in (stmt);
1806 if (call_expr_flags (call) & (ECF_CONST | ECF_PURE))
1808 add_virtual_operand (var, s_ann, opf_use, NULL, 0, -1, true);
1809 clobber_stats.unescapable_clobbers_avoided++;
1814 clobber_stats.unescapable_clobbers_avoided++;
1821 clobber_stats.static_write_clobbers_avoided++;
1823 add_virtual_operand (var, s_ann, opf_use, NULL, 0, -1, true);
1825 clobber_stats.static_read_clobbers_avoided++;
1828 add_virtual_operand (var, s_ann, opf_def, NULL, 0, -1, true);
1833 /* Add VUSE operands for .GLOBAL_VAR or all call clobbered variables in the
1837 add_call_read_ops (tree stmt, tree callee)
1841 stmt_ann_t s_ann = stmt_ann (stmt);
1844 /* if the function is not pure, it may reference memory. Add
1845 a VUSE for .GLOBAL_VAR if it has been created. See add_referenced_var
1846 for the heuristic used to decide whether to create .GLOBAL_VAR. */
1847 if (gimple_global_var (cfun))
1849 tree var = gimple_global_var (cfun);
1850 add_virtual_operand (var, s_ann, opf_use, NULL, 0, -1, true);
1854 not_read_b = callee ? ipa_reference_get_not_read_global (callee) : NULL;
1856 /* Add a VUSE for each call-clobbered variable. */
1857 EXECUTE_IF_SET_IN_BITMAP (gimple_call_clobbered_vars (cfun), 0, u, bi)
1859 tree var = referenced_var (u);
1860 tree real_var = var;
1863 clobber_stats.readonly_clobbers++;
1865 /* Not read and not written are computed on regular vars, not
1866 subvars, so look at the parent var if this is an SFT. */
1868 if (TREE_CODE (var) == STRUCT_FIELD_TAG)
1869 real_var = SFT_PARENT_VAR (var);
1871 not_read = not_read_b ? bitmap_bit_p (not_read_b, DECL_UID (real_var))
1876 clobber_stats.static_readonly_clobbers_avoided++;
1880 add_virtual_operand (var, s_ann, opf_use, NULL, 0, -1, true);
1885 /* A subroutine of get_expr_operands to handle CALL_EXPR. */
1888 get_call_expr_operands (tree stmt, tree expr)
1890 int call_flags = call_expr_flags (expr);
1892 stmt_ann_t ann = stmt_ann (stmt);
1894 ann->references_memory = true;
1896 /* If aliases have been computed already, add VDEF or VUSE
1897 operands for all the symbols that have been found to be
1899 if (gimple_aliases_computed_p (cfun)
1900 && !(call_flags & ECF_NOVOPS))
1902 /* A 'pure' or a 'const' function never call-clobbers anything.
1903 A 'noreturn' function might, but since we don't return anyway
1904 there is no point in recording that. */
1905 if (TREE_SIDE_EFFECTS (expr)
1906 && !(call_flags & (ECF_PURE | ECF_CONST | ECF_NORETURN)))
1907 add_call_clobber_ops (stmt, get_callee_fndecl (expr));
1908 else if (!(call_flags & ECF_CONST))
1909 add_call_read_ops (stmt, get_callee_fndecl (expr));
1912 /* Find uses in the called function. */
1913 get_expr_operands (stmt, &CALL_EXPR_FN (expr), opf_use);
1914 nargs = call_expr_nargs (expr);
1915 for (i = 0; i < nargs; i++)
1916 get_expr_operands (stmt, &CALL_EXPR_ARG (expr, i), opf_use);
1918 get_expr_operands (stmt, &CALL_EXPR_STATIC_CHAIN (expr), opf_use);
1922 /* Scan operands in the ASM_EXPR stmt referred to in INFO. */
1925 get_asm_expr_operands (tree stmt)
1929 const char **oconstraints;
1930 const char *constraint;
1931 bool allows_mem, allows_reg, is_inout;
1934 s_ann = stmt_ann (stmt);
1935 noutputs = list_length (ASM_OUTPUTS (stmt));
1936 oconstraints = (const char **) alloca ((noutputs) * sizeof (const char *));
1938 /* Gather all output operands. */
1939 for (i = 0, link = ASM_OUTPUTS (stmt); link; i++, link = TREE_CHAIN (link))
1941 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
1942 oconstraints[i] = constraint;
1943 parse_output_constraint (&constraint, i, 0, 0, &allows_mem,
1944 &allows_reg, &is_inout);
1946 /* This should have been split in gimplify_asm_expr. */
1947 gcc_assert (!allows_reg || !is_inout);
1949 /* Memory operands are addressable. Note that STMT needs the
1950 address of this operand. */
1951 if (!allows_reg && allows_mem)
1953 tree t = get_base_address (TREE_VALUE (link));
1954 if (t && DECL_P (t) && s_ann)
1955 add_to_addressable_set (t, &s_ann->addresses_taken);
1958 get_expr_operands (stmt, &TREE_VALUE (link), opf_def);
1961 /* Gather all input operands. */
1962 for (link = ASM_INPUTS (stmt); link; link = TREE_CHAIN (link))
1964 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
1965 parse_input_constraint (&constraint, 0, 0, noutputs, 0, oconstraints,
1966 &allows_mem, &allows_reg);
1968 /* Memory operands are addressable. Note that STMT needs the
1969 address of this operand. */
1970 if (!allows_reg && allows_mem)
1972 tree t = get_base_address (TREE_VALUE (link));
1973 if (t && DECL_P (t) && s_ann)
1974 add_to_addressable_set (t, &s_ann->addresses_taken);
1977 get_expr_operands (stmt, &TREE_VALUE (link), 0);
1980 /* Clobber all memory and addressable symbols for asm ("" : : : "memory"); */
1981 for (link = ASM_CLOBBERS (stmt); link; link = TREE_CHAIN (link))
1982 if (strcmp (TREE_STRING_POINTER (TREE_VALUE (link)), "memory") == 0)
1987 s_ann->references_memory = true;
1989 EXECUTE_IF_SET_IN_BITMAP (gimple_call_clobbered_vars (cfun), 0, i, bi)
1991 tree var = referenced_var (i);
1992 add_stmt_operand (&var, s_ann, opf_def | opf_implicit);
1995 EXECUTE_IF_SET_IN_BITMAP (gimple_addressable_vars (cfun), 0, i, bi)
1997 tree var = referenced_var (i);
1999 /* Subvars are explicitly represented in this list, so we
2000 don't need the original to be added to the clobber ops,
2001 but the original *will* be in this list because we keep
2002 the addressability of the original variable up-to-date
2003 to avoid confusing the back-end. */
2004 if (var_can_have_subvars (var)
2005 && get_subvars_for_var (var) != NULL)
2008 add_stmt_operand (&var, s_ann, opf_def | opf_implicit);
2015 /* Scan operands for the assignment expression EXPR in statement STMT. */
2018 get_modify_stmt_operands (tree stmt, tree expr)
2020 /* First get operands from the RHS. */
2021 get_expr_operands (stmt, &GIMPLE_STMT_OPERAND (expr, 1), opf_use);
2023 /* For the LHS, use a regular definition (opf_def) for GIMPLE
2024 registers. If the LHS is a store to memory, we will need
2025 a preserving definition (VDEF).
2027 Preserving definitions are those that modify a part of an
2028 aggregate object for which no subvars have been computed (or the
2029 reference does not correspond exactly to one of them). Stores
2030 through a pointer are also represented with VDEF operators.
2032 We used to distinguish between preserving and killing definitions.
2033 We always emit preserving definitions now. */
2034 get_expr_operands (stmt, &GIMPLE_STMT_OPERAND (expr, 0), opf_def);
2038 /* Recursively scan the expression pointed to by EXPR_P in statement
2039 STMT. FLAGS is one of the OPF_* constants modifying how to
2040 interpret the operands found. */
2043 get_expr_operands (tree stmt, tree *expr_p, int flags)
2045 enum tree_code code;
2046 enum tree_code_class codeclass;
2047 tree expr = *expr_p;
2048 stmt_ann_t s_ann = stmt_ann (stmt);
2053 code = TREE_CODE (expr);
2054 codeclass = TREE_CODE_CLASS (code);
2059 /* Taking the address of a variable does not represent a
2060 reference to it, but the fact that the statement takes its
2061 address will be of interest to some passes (e.g. alias
2063 add_to_addressable_set (TREE_OPERAND (expr, 0), &s_ann->addresses_taken);
2065 /* If the address is invariant, there may be no interesting
2066 variable references inside. */
2067 if (is_gimple_min_invariant (expr))
2070 /* Otherwise, there may be variables referenced inside but there
2071 should be no VUSEs created, since the referenced objects are
2072 not really accessed. The only operands that we should find
2073 here are ARRAY_REF indices which will always be real operands
2074 (GIMPLE does not allow non-registers as array indices). */
2075 flags |= opf_no_vops;
2076 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2080 case STRUCT_FIELD_TAG:
2081 case SYMBOL_MEMORY_TAG:
2082 case NAME_MEMORY_TAG:
2083 add_stmt_operand (expr_p, s_ann, flags);
2092 /* Add the subvars for a variable, if it has subvars, to DEFS
2093 or USES. Otherwise, add the variable itself. Whether it
2094 goes to USES or DEFS depends on the operand flags. */
2095 if (var_can_have_subvars (expr)
2096 && (svars = get_subvars_for_var (expr)))
2100 for (i = 0; VEC_iterate (tree, svars, i, subvar); ++i)
2101 add_stmt_operand (&subvar, s_ann, flags);
2104 add_stmt_operand (expr_p, s_ann, flags);
2109 case MISALIGNED_INDIRECT_REF:
2110 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), flags);
2113 case ALIGN_INDIRECT_REF:
2115 get_indirect_ref_operands (stmt, expr, flags, expr, 0, -1, true);
2118 case TARGET_MEM_REF:
2119 get_tmr_operands (stmt, expr, flags);
2123 case ARRAY_RANGE_REF:
2129 HOST_WIDE_INT offset, size, maxsize;
2132 if (TREE_THIS_VOLATILE (expr))
2133 s_ann->has_volatile_ops = true;
2135 /* This component reference becomes an access to all of the
2136 subvariables it can touch, if we can determine that, but
2137 *NOT* the real one. If we can't determine which fields we
2138 could touch, the recursion will eventually get to a
2139 variable and add *all* of its subvars, or whatever is the
2140 minimum correct subset. */
2141 ref = get_ref_base_and_extent (expr, &offset, &size, &maxsize);
2142 if (SSA_VAR_P (ref) && get_subvars_for_var (ref))
2144 subvar_t svars = get_subvars_for_var (ref);
2148 for (i = 0; VEC_iterate (tree, svars, i, subvar); ++i)
2152 if (overlap_subvar (offset, maxsize, subvar, &exact))
2154 int subvar_flags = flags;
2156 add_stmt_operand (&subvar, s_ann, subvar_flags);
2161 flags |= opf_no_vops;
2163 if ((DECL_P (ref) && TREE_THIS_VOLATILE (ref))
2164 || (TREE_CODE (ref) == SSA_NAME
2165 && TREE_THIS_VOLATILE (SSA_NAME_VAR (ref))))
2166 s_ann->has_volatile_ops = true;
2168 else if (TREE_CODE (ref) == INDIRECT_REF)
2170 get_indirect_ref_operands (stmt, ref, flags, expr, offset,
2172 flags |= opf_no_vops;
2175 /* Even if we found subvars above we need to ensure to see
2176 immediate uses for d in s.a[d]. In case of s.a having
2177 a subvar or we would miss it otherwise. */
2178 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2180 if (code == COMPONENT_REF)
2182 if (TREE_THIS_VOLATILE (TREE_OPERAND (expr, 1)))
2183 s_ann->has_volatile_ops = true;
2184 get_expr_operands (stmt, &TREE_OPERAND (expr, 2), opf_use);
2186 else if (code == ARRAY_REF || code == ARRAY_RANGE_REF)
2188 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), opf_use);
2189 get_expr_operands (stmt, &TREE_OPERAND (expr, 2), opf_use);
2190 get_expr_operands (stmt, &TREE_OPERAND (expr, 3), opf_use);
2196 case WITH_SIZE_EXPR:
2197 /* WITH_SIZE_EXPR is a pass-through reference to its first argument,
2198 and an rvalue reference to its second argument. */
2199 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), opf_use);
2200 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2204 get_call_expr_operands (stmt, expr);
2209 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), opf_use);
2210 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), opf_use);
2211 get_expr_operands (stmt, &TREE_OPERAND (expr, 2), opf_use);
2214 case GIMPLE_MODIFY_STMT:
2215 get_modify_stmt_operands (stmt, expr);
2220 /* General aggregate CONSTRUCTORs have been decomposed, but they
2221 are still in use as the COMPLEX_EXPR equivalent for vectors. */
2222 constructor_elt *ce;
2223 unsigned HOST_WIDE_INT idx;
2226 VEC_iterate (constructor_elt, CONSTRUCTOR_ELTS (expr), idx, ce);
2228 get_expr_operands (stmt, &ce->value, opf_use);
2234 case TRUTH_NOT_EXPR:
2235 case VIEW_CONVERT_EXPR:
2237 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2240 case TRUTH_AND_EXPR:
2242 case TRUTH_XOR_EXPR:
2248 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2249 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), flags);
2254 case REALIGN_LOAD_EXPR:
2256 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2257 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), flags);
2258 get_expr_operands (stmt, &TREE_OPERAND (expr, 2), flags);
2262 case CHANGE_DYNAMIC_TYPE_EXPR:
2263 get_expr_operands (stmt, &CHANGE_DYNAMIC_TYPE_LOCATION (expr), opf_use);
2268 tree init = OMP_FOR_INIT (expr);
2269 tree cond = OMP_FOR_COND (expr);
2270 tree incr = OMP_FOR_INCR (expr);
2271 tree c, clauses = OMP_FOR_CLAUSES (stmt);
2273 get_expr_operands (stmt, &GIMPLE_STMT_OPERAND (init, 0), opf_def);
2274 get_expr_operands (stmt, &GIMPLE_STMT_OPERAND (init, 1), opf_use);
2275 get_expr_operands (stmt, &TREE_OPERAND (cond, 1), opf_use);
2276 get_expr_operands (stmt, &TREE_OPERAND (GIMPLE_STMT_OPERAND (incr, 1), 1),
2279 c = find_omp_clause (clauses, OMP_CLAUSE_SCHEDULE);
2281 get_expr_operands (stmt, &OMP_CLAUSE_SCHEDULE_CHUNK_EXPR (c),
2288 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), opf_def);
2289 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), opf_use);
2295 tree c, clauses = OMP_PARALLEL_CLAUSES (stmt);
2297 if (OMP_PARALLEL_DATA_ARG (stmt))
2299 get_expr_operands (stmt, &OMP_PARALLEL_DATA_ARG (stmt), opf_use);
2300 add_to_addressable_set (OMP_PARALLEL_DATA_ARG (stmt),
2301 &s_ann->addresses_taken);
2304 c = find_omp_clause (clauses, OMP_CLAUSE_IF);
2306 get_expr_operands (stmt, &OMP_CLAUSE_IF_EXPR (c), opf_use);
2307 c = find_omp_clause (clauses, OMP_CLAUSE_NUM_THREADS);
2309 get_expr_operands (stmt, &OMP_CLAUSE_NUM_THREADS_EXPR (c), opf_use);
2315 get_expr_operands (stmt, &OMP_SECTIONS_CONTROL (expr), opf_def);
2319 case OMP_ATOMIC_LOAD:
2321 tree *addr = &TREE_OPERAND (expr, 1);
2322 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), opf_def);
2324 if (TREE_CODE (*addr) == ADDR_EXPR)
2325 get_expr_operands (stmt, &TREE_OPERAND (*addr, 0), opf_def);
2327 get_addr_dereference_operands (stmt, addr, opf_def,
2328 NULL_TREE, 0, -1, true);
2332 case OMP_ATOMIC_STORE:
2334 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), opf_use);
2350 case OMP_SECTIONS_SWITCH:
2351 /* Expressions that make no memory references. */
2355 if (codeclass == tcc_unary)
2357 if (codeclass == tcc_binary || codeclass == tcc_comparison)
2359 if (codeclass == tcc_constant || codeclass == tcc_type)
2363 /* If we get here, something has gone wrong. */
2364 #ifdef ENABLE_CHECKING
2365 fprintf (stderr, "unhandled expression in get_expr_operands():\n");
2367 fputs ("\n", stderr);
2373 /* Parse STMT looking for operands. When finished, the various
2374 build_* operand vectors will have potential operands in them. */
2377 parse_ssa_operands (tree stmt)
2379 enum tree_code code;
2381 code = TREE_CODE (stmt);
2384 case GIMPLE_MODIFY_STMT:
2385 get_modify_stmt_operands (stmt, stmt);
2389 get_expr_operands (stmt, &COND_EXPR_COND (stmt), opf_use);
2393 get_expr_operands (stmt, &SWITCH_COND (stmt), opf_use);
2397 get_asm_expr_operands (stmt);
2401 get_expr_operands (stmt, &TREE_OPERAND (stmt, 0), opf_use);
2405 get_expr_operands (stmt, &GOTO_DESTINATION (stmt), opf_use);
2409 get_expr_operands (stmt, &LABEL_EXPR_LABEL (stmt), opf_use);
2413 case CASE_LABEL_EXPR:
2414 case TRY_CATCH_EXPR:
2415 case TRY_FINALLY_EXPR:
2416 case EH_FILTER_EXPR:
2419 /* These nodes contain no variable references. */
2423 /* Notice that if get_expr_operands tries to use &STMT as the
2424 operand pointer (which may only happen for USE operands), we
2425 will fail in add_stmt_operand. This default will handle
2426 statements like empty statements, or CALL_EXPRs that may
2427 appear on the RHS of a statement or as statements themselves. */
2428 get_expr_operands (stmt, &stmt, opf_use);
2434 /* Create an operands cache for STMT. */
2437 build_ssa_operands (tree stmt)
2439 stmt_ann_t ann = get_stmt_ann (stmt);
2441 /* Initially assume that the statement has no volatile operands and
2442 makes no memory references. */
2443 ann->has_volatile_ops = false;
2444 ann->references_memory = false;
2445 /* Just clear the bitmap so we don't end up reallocating it over and over. */
2446 if (ann->addresses_taken)
2447 bitmap_clear (ann->addresses_taken);
2449 start_ssa_stmt_operands ();
2450 parse_ssa_operands (stmt);
2451 operand_build_sort_virtual (build_vuses);
2452 operand_build_sort_virtual (build_vdefs);
2453 finalize_ssa_stmt_operands (stmt);
2455 if (ann->addresses_taken && bitmap_empty_p (ann->addresses_taken))
2456 ann->addresses_taken = NULL;
2457 /* For added safety, assume that statements with volatile operands
2458 also reference memory. */
2459 if (ann->has_volatile_ops)
2460 ann->references_memory = true;
2463 /* Releases the operands of STMT back to their freelists, and clears
2464 the stmt operand lists. */
2467 free_stmt_operands (tree stmt)
2469 def_optype_p defs = DEF_OPS (stmt), last_def;
2470 use_optype_p uses = USE_OPS (stmt), last_use;
2471 voptype_p vuses = VUSE_OPS (stmt);
2472 voptype_p vdefs = VDEF_OPS (stmt), vdef, next_vdef;
2477 for (last_def = defs; last_def->next; last_def = last_def->next)
2479 last_def->next = gimple_ssa_operands (cfun)->free_defs;
2480 gimple_ssa_operands (cfun)->free_defs = defs;
2481 DEF_OPS (stmt) = NULL;
2486 for (last_use = uses; last_use->next; last_use = last_use->next)
2487 delink_imm_use (USE_OP_PTR (last_use));
2488 delink_imm_use (USE_OP_PTR (last_use));
2489 last_use->next = gimple_ssa_operands (cfun)->free_uses;
2490 gimple_ssa_operands (cfun)->free_uses = uses;
2491 USE_OPS (stmt) = NULL;
2496 for (i = 0; i < VUSE_NUM (vuses); i++)
2497 delink_imm_use (VUSE_OP_PTR (vuses, i));
2498 add_vop_to_freelist (vuses);
2499 VUSE_OPS (stmt) = NULL;
2504 for (vdef = vdefs; vdef; vdef = next_vdef)
2506 next_vdef = vdef->next;
2507 delink_imm_use (VDEF_OP_PTR (vdef, 0));
2508 add_vop_to_freelist (vdef);
2510 VDEF_OPS (stmt) = NULL;
2514 /* Free any operands vectors in OPS. */
2517 free_ssa_operands (stmt_operands_p ops)
2519 ops->def_ops = NULL;
2520 ops->use_ops = NULL;
2521 ops->vdef_ops = NULL;
2522 ops->vuse_ops = NULL;
2523 BITMAP_FREE (ops->loads);
2524 BITMAP_FREE (ops->stores);
2528 /* Get the operands of statement STMT. */
2531 update_stmt_operands (tree stmt)
2533 stmt_ann_t ann = get_stmt_ann (stmt);
2535 /* If update_stmt_operands is called before SSA is initialized, do
2537 if (!ssa_operands_active ())
2540 /* The optimizers cannot handle statements that are nothing but a
2541 _DECL. This indicates a bug in the gimplifier. */
2542 gcc_assert (!SSA_VAR_P (stmt));
2544 timevar_push (TV_TREE_OPS);
2546 gcc_assert (ann->modified);
2547 build_ssa_operands (stmt);
2550 timevar_pop (TV_TREE_OPS);
2554 /* Copies virtual operands from SRC to DST. */
2557 copy_virtual_operands (tree dest, tree src)
2560 voptype_p src_vuses, dest_vuses;
2561 voptype_p src_vdefs, dest_vdefs;
2562 struct voptype_d vuse;
2563 struct voptype_d vdef;
2564 stmt_ann_t dest_ann;
2566 VDEF_OPS (dest) = NULL;
2567 VUSE_OPS (dest) = NULL;
2569 dest_ann = get_stmt_ann (dest);
2570 BITMAP_FREE (dest_ann->operands.loads);
2571 BITMAP_FREE (dest_ann->operands.stores);
2573 if (LOADED_SYMS (src))
2575 dest_ann->operands.loads = BITMAP_ALLOC (&operands_bitmap_obstack);
2576 bitmap_copy (dest_ann->operands.loads, LOADED_SYMS (src));
2579 if (STORED_SYMS (src))
2581 dest_ann->operands.stores = BITMAP_ALLOC (&operands_bitmap_obstack);
2582 bitmap_copy (dest_ann->operands.stores, STORED_SYMS (src));
2585 /* Copy all the VUSE operators and corresponding operands. */
2587 for (src_vuses = VUSE_OPS (src); src_vuses; src_vuses = src_vuses->next)
2589 n = VUSE_NUM (src_vuses);
2590 dest_vuses = add_vuse_op (dest, NULL_TREE, n, dest_vuses);
2591 for (i = 0; i < n; i++)
2592 SET_USE (VUSE_OP_PTR (dest_vuses, i), VUSE_OP (src_vuses, i));
2594 if (VUSE_OPS (dest) == NULL)
2595 VUSE_OPS (dest) = vuse.next;
2598 /* Copy all the VDEF operators and corresponding operands. */
2600 for (src_vdefs = VDEF_OPS (src); src_vdefs; src_vdefs = src_vdefs->next)
2602 n = VUSE_NUM (src_vdefs);
2603 dest_vdefs = add_vdef_op (dest, NULL_TREE, n, dest_vdefs);
2604 VDEF_RESULT (dest_vdefs) = VDEF_RESULT (src_vdefs);
2605 for (i = 0; i < n; i++)
2606 SET_USE (VUSE_OP_PTR (dest_vdefs, i), VUSE_OP (src_vdefs, i));
2608 if (VDEF_OPS (dest) == NULL)
2609 VDEF_OPS (dest) = vdef.next;
2614 /* Specifically for use in DOM's expression analysis. Given a store, we
2615 create an artificial stmt which looks like a load from the store, this can
2616 be used to eliminate redundant loads. OLD_OPS are the operands from the
2617 store stmt, and NEW_STMT is the new load which represents a load of the
2621 create_ssa_artificial_load_stmt (tree new_stmt, tree old_stmt)
2625 use_operand_p use_p;
2628 get_stmt_ann (new_stmt);
2630 /* Process NEW_STMT looking for operands. */
2631 start_ssa_stmt_operands ();
2632 parse_ssa_operands (new_stmt);
2634 for (i = 0; VEC_iterate (tree, build_vuses, i, op); i++)
2635 if (TREE_CODE (op) != SSA_NAME)
2636 var_ann (op)->in_vuse_list = false;
2638 for (i = 0; VEC_iterate (tree, build_vuses, i, op); i++)
2639 if (TREE_CODE (op) != SSA_NAME)
2640 var_ann (op)->in_vdef_list = false;
2642 /* Remove any virtual operands that were found. */
2643 VEC_truncate (tree, build_vdefs, 0);
2644 VEC_truncate (tree, build_vuses, 0);
2646 /* For each VDEF on the original statement, we want to create a
2647 VUSE of the VDEF result operand on the new statement. */
2648 FOR_EACH_SSA_TREE_OPERAND (op, old_stmt, iter, SSA_OP_VDEF)
2651 finalize_ssa_stmt_operands (new_stmt);
2653 /* All uses in this fake stmt must not be in the immediate use lists. */
2654 FOR_EACH_SSA_USE_OPERAND (use_p, new_stmt, iter, SSA_OP_ALL_USES)
2655 delink_imm_use (use_p);
2659 /* Swap operands EXP0 and EXP1 in statement STMT. No attempt is done
2660 to test the validity of the swap operation. */
2663 swap_tree_operands (tree stmt, tree *exp0, tree *exp1)
2669 /* If the operand cache is active, attempt to preserve the relative
2670 positions of these two operands in their respective immediate use
2672 if (ssa_operands_active () && op0 != op1)
2674 use_optype_p use0, use1, ptr;
2677 /* Find the 2 operands in the cache, if they are there. */
2678 for (ptr = USE_OPS (stmt); ptr; ptr = ptr->next)
2679 if (USE_OP_PTR (ptr)->use == exp0)
2685 for (ptr = USE_OPS (stmt); ptr; ptr = ptr->next)
2686 if (USE_OP_PTR (ptr)->use == exp1)
2692 /* If both uses don't have operand entries, there isn't much we can do
2693 at this point. Presumably we don't need to worry about it. */
2696 tree *tmp = USE_OP_PTR (use1)->use;
2697 USE_OP_PTR (use1)->use = USE_OP_PTR (use0)->use;
2698 USE_OP_PTR (use0)->use = tmp;
2702 /* Now swap the data. */
2708 /* Add the base address of REF to the set *ADDRESSES_TAKEN. If
2709 *ADDRESSES_TAKEN is NULL, a new set is created. REF may be
2710 a single variable whose address has been taken or any other valid
2711 GIMPLE memory reference (structure reference, array, etc). If the
2712 base address of REF is a decl that has sub-variables, also add all
2713 of its sub-variables. */
2716 add_to_addressable_set (tree ref, bitmap *addresses_taken)
2721 gcc_assert (addresses_taken);
2723 /* Note that it is *NOT OKAY* to use the target of a COMPONENT_REF
2724 as the only thing we take the address of. If VAR is a structure,
2725 taking the address of a field means that the whole structure may
2726 be referenced using pointer arithmetic. See PR 21407 and the
2727 ensuing mailing list discussion. */
2728 var = get_base_address (ref);
2729 if (var && SSA_VAR_P (var))
2731 if (*addresses_taken == NULL)
2732 *addresses_taken = BITMAP_GGC_ALLOC ();
2734 if (var_can_have_subvars (var)
2735 && (svars = get_subvars_for_var (var)))
2739 for (i = 0; VEC_iterate (tree, svars, i, subvar); ++i)
2741 bitmap_set_bit (*addresses_taken, DECL_UID (subvar));
2742 TREE_ADDRESSABLE (subvar) = 1;
2747 bitmap_set_bit (*addresses_taken, DECL_UID (var));
2748 TREE_ADDRESSABLE (var) = 1;
2754 /* Scan the immediate_use list for VAR making sure its linked properly.
2755 Return TRUE if there is a problem and emit an error message to F. */
2758 verify_imm_links (FILE *f, tree var)
2760 use_operand_p ptr, prev, list;
2763 gcc_assert (TREE_CODE (var) == SSA_NAME);
2765 list = &(SSA_NAME_IMM_USE_NODE (var));
2766 gcc_assert (list->use == NULL);
2768 if (list->prev == NULL)
2770 gcc_assert (list->next == NULL);
2776 for (ptr = list->next; ptr != list; )
2778 if (prev != ptr->prev)
2781 if (ptr->use == NULL)
2782 goto error; /* 2 roots, or SAFE guard node. */
2783 else if (*(ptr->use) != var)
2789 /* Avoid infinite loops. 50,000,000 uses probably indicates a
2791 if (count++ > 50000000)
2795 /* Verify list in the other direction. */
2797 for (ptr = list->prev; ptr != list; )
2799 if (prev != ptr->next)
2813 if (ptr->stmt && stmt_modified_p (ptr->stmt))
2815 fprintf (f, " STMT MODIFIED. - <%p> ", (void *)ptr->stmt);
2816 print_generic_stmt (f, ptr->stmt, TDF_SLIM);
2818 fprintf (f, " IMM ERROR : (use_p : tree - %p:%p)", (void *)ptr,
2820 print_generic_expr (f, USE_FROM_PTR (ptr), TDF_SLIM);
2826 /* Dump all the immediate uses to FILE. */
2829 dump_immediate_uses_for (FILE *file, tree var)
2831 imm_use_iterator iter;
2832 use_operand_p use_p;
2834 gcc_assert (var && TREE_CODE (var) == SSA_NAME);
2836 print_generic_expr (file, var, TDF_SLIM);
2837 fprintf (file, " : -->");
2838 if (has_zero_uses (var))
2839 fprintf (file, " no uses.\n");
2841 if (has_single_use (var))
2842 fprintf (file, " single use.\n");
2844 fprintf (file, "%d uses.\n", num_imm_uses (var));
2846 FOR_EACH_IMM_USE_FAST (use_p, iter, var)
2848 if (use_p->stmt == NULL && use_p->use == NULL)
2849 fprintf (file, "***end of stmt iterator marker***\n");
2851 if (!is_gimple_reg (USE_FROM_PTR (use_p)))
2852 print_generic_stmt (file, USE_STMT (use_p), TDF_VOPS|TDF_MEMSYMS);
2854 print_generic_stmt (file, USE_STMT (use_p), TDF_SLIM);
2856 fprintf(file, "\n");
2860 /* Dump all the immediate uses to FILE. */
2863 dump_immediate_uses (FILE *file)
2868 fprintf (file, "Immediate_uses: \n\n");
2869 for (x = 1; x < num_ssa_names; x++)
2874 dump_immediate_uses_for (file, var);
2879 /* Dump def-use edges on stderr. */
2882 debug_immediate_uses (void)
2884 dump_immediate_uses (stderr);
2888 /* Dump def-use edges on stderr. */
2891 debug_immediate_uses_for (tree var)
2893 dump_immediate_uses_for (stderr, var);
2897 /* Create a new change buffer for the statement pointed by STMT_P and
2898 push the buffer into SCB_STACK. Each change buffer
2899 records state information needed to determine what changed in the
2900 statement. Mainly, this keeps track of symbols that may need to be
2901 put into SSA form, SSA name replacements and other information
2902 needed to keep the SSA form up to date. */
2905 push_stmt_changes (tree *stmt_p)
2912 /* It makes no sense to keep track of PHI nodes. */
2913 if (TREE_CODE (stmt) == PHI_NODE)
2916 buf = XNEW (struct scb_d);
2917 memset (buf, 0, sizeof *buf);
2919 buf->stmt_p = stmt_p;
2921 if (stmt_references_memory_p (stmt))
2926 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_VUSE)
2928 tree sym = TREE_CODE (op) == SSA_NAME ? SSA_NAME_VAR (op) : op;
2929 if (buf->loads == NULL)
2930 buf->loads = BITMAP_ALLOC (NULL);
2931 bitmap_set_bit (buf->loads, DECL_UID (sym));
2934 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_VDEF)
2936 tree sym = TREE_CODE (op) == SSA_NAME ? SSA_NAME_VAR (op) : op;
2937 if (buf->stores == NULL)
2938 buf->stores = BITMAP_ALLOC (NULL);
2939 bitmap_set_bit (buf->stores, DECL_UID (sym));
2943 VEC_safe_push (scb_t, heap, scb_stack, buf);
2947 /* Given two sets S1 and S2, mark the symbols that differ in S1 and S2
2948 for renaming. The set to mark for renaming is (S1 & ~S2) | (S2 & ~S1). */
2951 mark_difference_for_renaming (bitmap s1, bitmap s2)
2953 if (s1 == NULL && s2 == NULL)
2956 if (s1 && s2 == NULL)
2957 mark_set_for_renaming (s1);
2958 else if (s1 == NULL && s2)
2959 mark_set_for_renaming (s2);
2960 else if (!bitmap_equal_p (s1, s2))
2962 bitmap t1 = BITMAP_ALLOC (NULL);
2963 bitmap t2 = BITMAP_ALLOC (NULL);
2965 bitmap_and_compl (t1, s1, s2);
2966 bitmap_and_compl (t2, s2, s1);
2967 bitmap_ior_into (t1, t2);
2968 mark_set_for_renaming (t1);
2976 /* Pop the top SCB from SCB_STACK and act on the differences between
2977 what was recorded by push_stmt_changes and the current state of
2981 pop_stmt_changes (tree *stmt_p)
2985 bitmap loads, stores;
2990 /* It makes no sense to keep track of PHI nodes. */
2991 if (TREE_CODE (stmt) == PHI_NODE)
2994 buf = VEC_pop (scb_t, scb_stack);
2995 gcc_assert (stmt_p == buf->stmt_p);
2997 /* Force an operand re-scan on the statement and mark any newly
2998 exposed variables. */
3001 /* Determine whether any memory symbols need to be renamed. If the
3002 sets of loads and stores are different after the statement is
3003 modified, then the affected symbols need to be renamed.
3005 Note that it may be possible for the statement to not reference
3006 memory anymore, but we still need to act on the differences in
3007 the sets of symbols. */
3008 loads = stores = NULL;
3009 if (stmt_references_memory_p (stmt))
3014 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_VUSE)
3016 tree sym = TREE_CODE (op) == SSA_NAME ? SSA_NAME_VAR (op) : op;
3018 loads = BITMAP_ALLOC (NULL);
3019 bitmap_set_bit (loads, DECL_UID (sym));
3022 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_VDEF)
3024 tree sym = TREE_CODE (op) == SSA_NAME ? SSA_NAME_VAR (op) : op;
3026 stores = BITMAP_ALLOC (NULL);
3027 bitmap_set_bit (stores, DECL_UID (sym));
3031 /* If LOADS is different from BUF->LOADS, the affected
3032 symbols need to be marked for renaming. */
3033 mark_difference_for_renaming (loads, buf->loads);
3035 /* Similarly for STORES and BUF->STORES. */
3036 mark_difference_for_renaming (stores, buf->stores);
3038 /* Mark all the naked GIMPLE register operands for renaming. */
3039 FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_DEF|SSA_OP_USE)
3041 mark_sym_for_renaming (op);
3043 /* FIXME, need to add more finalizers here. Cleanup EH info,
3044 recompute invariants for address expressions, add
3045 SSA replacement mappings, etc. For instance, given
3046 testsuite/gcc.c-torture/compile/pr16808.c, we fold a statement of
3049 # SMT.4_20 = VDEF <SMT.4_16>
3052 So, the VDEF will disappear, but instead of marking SMT.4 for
3053 renaming it would be far more efficient to establish a
3054 replacement mapping that would replace every reference of
3055 SMT.4_20 with SMT.4_16. */
3057 /* Free memory used by the buffer. */
3058 BITMAP_FREE (buf->loads);
3059 BITMAP_FREE (buf->stores);
3060 BITMAP_FREE (loads);
3061 BITMAP_FREE (stores);
3067 /* Discard the topmost change buffer from SCB_STACK. This is useful
3068 when the caller realized that it did not actually modified the
3069 statement. It avoids the expensive operand re-scan. */
3072 discard_stmt_changes (tree *stmt_p)
3077 /* It makes no sense to keep track of PHI nodes. */
3079 if (TREE_CODE (stmt) == PHI_NODE)
3082 buf = VEC_pop (scb_t, scb_stack);
3083 gcc_assert (stmt_p == buf->stmt_p);
3085 /* Free memory used by the buffer. */
3086 BITMAP_FREE (buf->loads);
3087 BITMAP_FREE (buf->stores);
3093 /* Returns true if statement STMT may access memory. */
3096 stmt_references_memory_p (tree stmt)
3098 if (!gimple_ssa_operands (cfun)->ops_active || TREE_CODE (stmt) == PHI_NODE)
3101 return stmt_ann (stmt)->references_memory;