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 || ann->in_vdef_list)
1170 ann->in_vuse_list = true;
1174 sym = SSA_NAME_VAR (var);
1176 VEC_safe_push (tree, heap, build_vuses, var);
1177 bitmap_set_bit (build_loads, DECL_UID (sym));
1181 /* REF is a tree that contains the entire pointer dereference
1182 expression, if available, or NULL otherwise. ALIAS is the variable
1183 we are asking if REF can access. OFFSET and SIZE come from the
1184 memory access expression that generated this virtual operand. */
1187 access_can_touch_variable (tree ref, tree alias, HOST_WIDE_INT offset,
1190 bool offsetgtz = offset > 0;
1191 unsigned HOST_WIDE_INT uoffset = (unsigned HOST_WIDE_INT) offset;
1192 tree base = ref ? get_base_address (ref) : NULL;
1194 /* If ALIAS is .GLOBAL_VAR then the memory reference REF must be
1195 using a call-clobbered memory tag. By definition, call-clobbered
1196 memory tags can always touch .GLOBAL_VAR. */
1197 if (alias == gimple_global_var (cfun))
1200 /* If ALIAS is an SFT, it can't be touched if the offset
1201 and size of the access is not overlapping with the SFT offset and
1202 size. This is only true if we are accessing through a pointer
1203 to a type that is the same as SFT_PARENT_VAR. Otherwise, we may
1204 be accessing through a pointer to some substruct of the
1205 structure, and if we try to prune there, we will have the wrong
1206 offset, and get the wrong answer.
1207 i.e., we can't prune without more work if we have something like
1213 const char *byte_op;
1221 foo = &targetm.asm_out.aligned_op;
1224 SFT.1, which represents hi, will have SFT_OFFSET=32 because in
1225 terms of SFT_PARENT_VAR, that is where it is.
1226 However, the access through the foo pointer will be at offset 0. */
1228 && TREE_CODE (alias) == STRUCT_FIELD_TAG
1230 && TREE_TYPE (base) == TREE_TYPE (SFT_PARENT_VAR (alias))
1231 && !overlap_subvar (offset, size, alias, NULL))
1233 #ifdef ACCESS_DEBUGGING
1234 fprintf (stderr, "Access to ");
1235 print_generic_expr (stderr, ref, 0);
1236 fprintf (stderr, " may not touch ");
1237 print_generic_expr (stderr, alias, 0);
1238 fprintf (stderr, " in function %s\n", get_name (current_function_decl));
1243 /* Without strict aliasing, it is impossible for a component access
1244 through a pointer to touch a random variable, unless that
1245 variable *is* a structure or a pointer.
1247 That is, given p->c, and some random global variable b,
1248 there is no legal way that p->c could be an access to b.
1250 Without strict aliasing on, we consider it legal to do something
1253 struct foos { int l; };
1255 static struct foos *getfoo(void);
1258 struct foos *f = getfoo();
1265 static struct foos *getfoo(void)
1266 { return (struct foos *)&foo; }
1268 (taken from 20000623-1.c)
1270 The docs also say/imply that access through union pointers
1271 is legal (but *not* if you take the address of the union member,
1272 i.e. the inverse), such that you can do
1282 U *pretmp = (U*)&rv;
1286 To implement this, we just punt on accesses through union
1290 && flag_strict_aliasing
1291 && TREE_CODE (ref) != INDIRECT_REF
1293 && (TREE_CODE (base) != INDIRECT_REF
1294 || TREE_CODE (TREE_TYPE (base)) != UNION_TYPE)
1295 && !AGGREGATE_TYPE_P (TREE_TYPE (alias))
1296 && TREE_CODE (TREE_TYPE (alias)) != COMPLEX_TYPE
1297 && !var_ann (alias)->is_heapvar
1298 /* When the struct has may_alias attached to it, we need not to
1300 && get_alias_set (base))
1302 #ifdef ACCESS_DEBUGGING
1303 fprintf (stderr, "Access to ");
1304 print_generic_expr (stderr, ref, 0);
1305 fprintf (stderr, " may not touch ");
1306 print_generic_expr (stderr, alias, 0);
1307 fprintf (stderr, " in function %s\n", get_name (current_function_decl));
1312 /* If the offset of the access is greater than the size of one of
1313 the possible aliases, it can't be touching that alias, because it
1314 would be past the end of the structure. */
1316 && flag_strict_aliasing
1317 && TREE_CODE (ref) != INDIRECT_REF
1319 && !POINTER_TYPE_P (TREE_TYPE (alias))
1321 && DECL_SIZE (alias)
1322 && TREE_CODE (DECL_SIZE (alias)) == INTEGER_CST
1323 && uoffset > TREE_INT_CST_LOW (DECL_SIZE (alias)))
1325 #ifdef ACCESS_DEBUGGING
1326 fprintf (stderr, "Access to ");
1327 print_generic_expr (stderr, ref, 0);
1328 fprintf (stderr, " may not touch ");
1329 print_generic_expr (stderr, alias, 0);
1330 fprintf (stderr, " in function %s\n", get_name (current_function_decl));
1339 /* Add VAR to the virtual operands array. FLAGS is as in
1340 get_expr_operands. FULL_REF is a tree that contains the entire
1341 pointer dereference expression, if available, or NULL otherwise.
1342 OFFSET and SIZE come from the memory access expression that
1343 generated this virtual operand. IS_CALL_SITE is true if the
1344 affected statement is a call site. */
1347 add_virtual_operand (tree var, stmt_ann_t s_ann, int flags,
1348 tree full_ref, HOST_WIDE_INT offset,
1349 HOST_WIDE_INT size, bool is_call_site)
1351 bitmap aliases = NULL;
1355 sym = (TREE_CODE (var) == SSA_NAME ? SSA_NAME_VAR (var) : var);
1356 v_ann = var_ann (sym);
1358 /* Mark the statement as having memory operands. */
1359 s_ann->references_memory = true;
1361 /* Mark statements with volatile operands. Optimizers should back
1362 off from statements having volatile operands. */
1363 if (TREE_THIS_VOLATILE (sym) && s_ann)
1364 s_ann->has_volatile_ops = true;
1366 /* If the variable cannot be modified and this is a VDEF change
1367 it into a VUSE. This happens when read-only variables are marked
1368 call-clobbered and/or aliased to writable variables. So we only
1369 check that this only happens on non-specific stores.
1371 Note that if this is a specific store, i.e. associated with a
1372 GIMPLE_MODIFY_STMT, then we can't suppress the VDEF, lest we run
1373 into validation problems.
1375 This can happen when programs cast away const, leaving us with a
1376 store to read-only memory. If the statement is actually executed
1377 at runtime, then the program is ill formed. If the statement is
1378 not executed then all is well. At the very least, we cannot ICE. */
1379 if ((flags & opf_implicit) && unmodifiable_var_p (var))
1382 /* The variable is not a GIMPLE register. Add it (or its aliases) to
1383 virtual operands, unless the caller has specifically requested
1384 not to add virtual operands (used when adding operands inside an
1385 ADDR_EXPR expression). */
1386 if (flags & opf_no_vops)
1390 aliases = MTAG_ALIASES (var);
1392 if (aliases == NULL)
1394 if (s_ann && !gimple_aliases_computed_p (cfun))
1395 s_ann->has_volatile_ops = true;
1397 /* The variable is not aliased or it is an alias tag. */
1398 if (flags & opf_def)
1409 /* The variable is aliased. Add its aliases to the virtual
1411 gcc_assert (!bitmap_empty_p (aliases));
1413 if (flags & opf_def)
1415 bool none_added = true;
1416 EXECUTE_IF_SET_IN_BITMAP (aliases, 0, i, bi)
1418 al = referenced_var (i);
1419 if (!access_can_touch_variable (full_ref, al, offset, size))
1422 /* Call-clobbered tags may have non-call-clobbered
1423 symbols in their alias sets. Ignore them if we are
1424 adding VOPs for a call site. */
1425 if (is_call_site && !is_call_clobbered (al))
1432 /* If the variable is also an alias tag, add a virtual
1433 operand for it, otherwise we will miss representing
1434 references to the members of the variable's alias set.
1435 This fixes the bug in gcc.c-torture/execute/20020503-1.c.
1437 It is also necessary to add bare defs on clobbers for
1438 SMT's, so that bare SMT uses caused by pruning all the
1439 aliases will link up properly with calls. In order to
1440 keep the number of these bare defs we add down to the
1441 minimum necessary, we keep track of which SMT's were used
1442 alone in statement vdefs or VUSEs. */
1444 || (TREE_CODE (var) == SYMBOL_MEMORY_TAG
1452 bool none_added = true;
1453 EXECUTE_IF_SET_IN_BITMAP (aliases, 0, i, bi)
1455 al = referenced_var (i);
1456 if (!access_can_touch_variable (full_ref, al, offset, size))
1459 /* Call-clobbered tags may have non-call-clobbered
1460 symbols in their alias sets. Ignore them if we are
1461 adding VOPs for a call site. */
1462 if (is_call_site && !is_call_clobbered (al))
1469 /* Even if no aliases have been added, we still need to
1470 establish def-use and use-def chains, lest
1471 transformations think that this is not a memory
1472 reference. For an example of this scenario, see
1473 testsuite/g++.dg/opt/cleanup1.C. */
1481 /* Add *VAR_P to the appropriate operand array for S_ANN. FLAGS is as in
1482 get_expr_operands. If *VAR_P is a GIMPLE register, it will be added to
1483 the statement's real operands, otherwise it is added to virtual
1487 add_stmt_operand (tree *var_p, stmt_ann_t s_ann, int flags)
1492 gcc_assert (SSA_VAR_P (*var_p) && s_ann);
1495 sym = (TREE_CODE (var) == SSA_NAME ? SSA_NAME_VAR (var) : var);
1496 v_ann = var_ann (sym);
1498 /* Mark statements with volatile operands. */
1499 if (TREE_THIS_VOLATILE (sym))
1500 s_ann->has_volatile_ops = true;
1502 if (is_gimple_reg (sym))
1504 /* The variable is a GIMPLE register. Add it to real operands. */
1505 if (flags & opf_def)
1511 add_virtual_operand (var, s_ann, flags, NULL_TREE, 0, -1, false);
1515 /* A subroutine of get_expr_operands to handle INDIRECT_REF,
1516 ALIGN_INDIRECT_REF and MISALIGNED_INDIRECT_REF.
1518 STMT is the statement being processed, EXPR is the INDIRECT_REF
1521 FLAGS is as in get_expr_operands.
1523 FULL_REF contains the full pointer dereference expression, if we
1524 have it, or NULL otherwise.
1526 OFFSET and SIZE are the location of the access inside the
1527 dereferenced pointer, if known.
1529 RECURSE_ON_BASE should be set to true if we want to continue
1530 calling get_expr_operands on the base pointer, and false if
1531 something else will do it for us. */
1534 get_indirect_ref_operands (tree stmt, tree expr, int flags,
1536 HOST_WIDE_INT offset, HOST_WIDE_INT size,
1537 bool recurse_on_base)
1539 tree *pptr = &TREE_OPERAND (expr, 0);
1541 stmt_ann_t s_ann = stmt_ann (stmt);
1543 s_ann->references_memory = true;
1544 if (s_ann && TREE_THIS_VOLATILE (expr))
1545 s_ann->has_volatile_ops = true;
1547 if (SSA_VAR_P (ptr))
1549 struct ptr_info_def *pi = NULL;
1551 /* If PTR has flow-sensitive points-to information, use it. */
1552 if (TREE_CODE (ptr) == SSA_NAME
1553 && (pi = SSA_NAME_PTR_INFO (ptr)) != NULL
1554 && pi->name_mem_tag)
1556 /* PTR has its own memory tag. Use it. */
1557 add_virtual_operand (pi->name_mem_tag, s_ann, flags,
1558 full_ref, offset, size, false);
1562 /* If PTR is not an SSA_NAME or it doesn't have a name
1563 tag, use its symbol memory tag. */
1566 /* If we are emitting debugging dumps, display a warning if
1567 PTR is an SSA_NAME with no flow-sensitive alias
1568 information. That means that we may need to compute
1571 && TREE_CODE (ptr) == SSA_NAME
1575 "NOTE: no flow-sensitive alias info for ");
1576 print_generic_expr (dump_file, ptr, dump_flags);
1577 fprintf (dump_file, " in ");
1578 print_generic_stmt (dump_file, stmt, dump_flags);
1581 if (TREE_CODE (ptr) == SSA_NAME)
1582 ptr = SSA_NAME_VAR (ptr);
1583 v_ann = var_ann (ptr);
1585 if (v_ann->symbol_mem_tag)
1586 add_virtual_operand (v_ann->symbol_mem_tag, s_ann, flags,
1587 full_ref, offset, size, false);
1589 /* Aliasing information is missing; mark statement as
1590 volatile so we won't optimize it out too actively. */
1592 && !gimple_aliases_computed_p (cfun)
1593 && (flags & opf_def))
1594 s_ann->has_volatile_ops = true;
1597 else if (TREE_CODE (ptr) == INTEGER_CST)
1599 /* If a constant is used as a pointer, we can't generate a real
1600 operand for it but we mark the statement volatile to prevent
1601 optimizations from messing things up. */
1603 s_ann->has_volatile_ops = true;
1608 /* Ok, this isn't even is_gimple_min_invariant. Something's broke. */
1612 /* If requested, add a USE operand for the base pointer. */
1613 if (recurse_on_base)
1614 get_expr_operands (stmt, pptr, opf_use);
1618 /* A subroutine of get_expr_operands to handle TARGET_MEM_REF. */
1621 get_tmr_operands (tree stmt, tree expr, int flags)
1624 HOST_WIDE_INT offset, size, maxsize;
1626 stmt_ann_t s_ann = stmt_ann (stmt);
1628 /* This statement references memory. */
1629 s_ann->references_memory = 1;
1631 /* First record the real operands. */
1632 get_expr_operands (stmt, &TMR_BASE (expr), opf_use);
1633 get_expr_operands (stmt, &TMR_INDEX (expr), opf_use);
1635 if (TMR_SYMBOL (expr))
1636 add_to_addressable_set (TMR_SYMBOL (expr), &s_ann->addresses_taken);
1638 tag = TMR_TAG (expr);
1641 /* Something weird, so ensure that we will be careful. */
1642 s_ann->has_volatile_ops = true;
1648 get_expr_operands (stmt, &tag, flags);
1652 ref = get_ref_base_and_extent (tag, &offset, &size, &maxsize);
1653 gcc_assert (ref != NULL_TREE);
1654 svars = get_subvars_for_var (ref);
1655 for (sv = svars; sv; sv = sv->next)
1659 if (overlap_subvar (offset, maxsize, sv->var, &exact))
1660 add_stmt_operand (&sv->var, s_ann, flags);
1665 /* Add clobbering definitions for .GLOBAL_VAR or for each of the call
1666 clobbered variables in the function. */
1669 add_call_clobber_ops (tree stmt, tree callee)
1673 stmt_ann_t s_ann = stmt_ann (stmt);
1674 bitmap not_read_b, not_written_b;
1676 /* Functions that are not const, pure or never return may clobber
1677 call-clobbered variables. */
1679 s_ann->makes_clobbering_call = true;
1681 /* If we created .GLOBAL_VAR earlier, just use it. */
1682 if (gimple_global_var (cfun))
1684 tree var = gimple_global_var (cfun);
1685 add_virtual_operand (var, s_ann, opf_def, NULL, 0, -1, true);
1689 /* Get info for local and module level statics. There is a bit
1690 set for each static if the call being processed does not read
1691 or write that variable. */
1692 not_read_b = callee ? ipa_reference_get_not_read_global (callee) : NULL;
1693 not_written_b = callee ? ipa_reference_get_not_written_global (callee) : NULL;
1695 /* Add a VDEF operand for every call clobbered variable. */
1696 EXECUTE_IF_SET_IN_BITMAP (gimple_call_clobbered_vars (cfun), 0, u, bi)
1698 tree var = referenced_var_lookup (u);
1699 unsigned int escape_mask = var_ann (var)->escape_mask;
1700 tree real_var = var;
1704 /* Not read and not written are computed on regular vars, not
1705 subvars, so look at the parent var if this is an SFT. */
1706 if (TREE_CODE (var) == STRUCT_FIELD_TAG)
1707 real_var = SFT_PARENT_VAR (var);
1709 not_read = not_read_b
1710 ? bitmap_bit_p (not_read_b, DECL_UID (real_var))
1713 not_written = not_written_b
1714 ? bitmap_bit_p (not_written_b, DECL_UID (real_var))
1716 gcc_assert (!unmodifiable_var_p (var));
1718 clobber_stats.clobbered_vars++;
1720 /* See if this variable is really clobbered by this function. */
1722 /* Trivial case: Things escaping only to pure/const are not
1723 clobbered by non-pure-const, and only read by pure/const. */
1724 if ((escape_mask & ~(ESCAPE_TO_PURE_CONST)) == 0)
1726 tree call = get_call_expr_in (stmt);
1727 if (call_expr_flags (call) & (ECF_CONST | ECF_PURE))
1729 add_virtual_operand (var, s_ann, opf_use, NULL, 0, -1, true);
1730 clobber_stats.unescapable_clobbers_avoided++;
1735 clobber_stats.unescapable_clobbers_avoided++;
1742 clobber_stats.static_write_clobbers_avoided++;
1744 add_virtual_operand (var, s_ann, opf_use, NULL, 0, -1, true);
1746 clobber_stats.static_read_clobbers_avoided++;
1749 add_virtual_operand (var, s_ann, opf_def, NULL, 0, -1, true);
1754 /* Add VUSE operands for .GLOBAL_VAR or all call clobbered variables in the
1758 add_call_read_ops (tree stmt, tree callee)
1762 stmt_ann_t s_ann = stmt_ann (stmt);
1765 /* if the function is not pure, it may reference memory. Add
1766 a VUSE for .GLOBAL_VAR if it has been created. See add_referenced_var
1767 for the heuristic used to decide whether to create .GLOBAL_VAR. */
1768 if (gimple_global_var (cfun))
1770 tree var = gimple_global_var (cfun);
1771 add_virtual_operand (var, s_ann, opf_use, NULL, 0, -1, true);
1775 not_read_b = callee ? ipa_reference_get_not_read_global (callee) : NULL;
1777 /* Add a VUSE for each call-clobbered variable. */
1778 EXECUTE_IF_SET_IN_BITMAP (gimple_call_clobbered_vars (cfun), 0, u, bi)
1780 tree var = referenced_var (u);
1781 tree real_var = var;
1784 clobber_stats.readonly_clobbers++;
1786 /* Not read and not written are computed on regular vars, not
1787 subvars, so look at the parent var if this is an SFT. */
1789 if (TREE_CODE (var) == STRUCT_FIELD_TAG)
1790 real_var = SFT_PARENT_VAR (var);
1792 not_read = not_read_b ? bitmap_bit_p (not_read_b, DECL_UID (real_var))
1797 clobber_stats.static_readonly_clobbers_avoided++;
1801 add_virtual_operand (var, s_ann, opf_use, NULL, 0, -1, true);
1806 /* A subroutine of get_expr_operands to handle CALL_EXPR. */
1809 get_call_expr_operands (tree stmt, tree expr)
1811 int call_flags = call_expr_flags (expr);
1813 stmt_ann_t ann = stmt_ann (stmt);
1815 ann->references_memory = true;
1817 /* If aliases have been computed already, add VDEF or VUSE
1818 operands for all the symbols that have been found to be
1820 if (gimple_aliases_computed_p (cfun)
1821 && !(call_flags & ECF_NOVOPS))
1823 /* A 'pure' or a 'const' function never call-clobbers anything.
1824 A 'noreturn' function might, but since we don't return anyway
1825 there is no point in recording that. */
1826 if (TREE_SIDE_EFFECTS (expr)
1827 && !(call_flags & (ECF_PURE | ECF_CONST | ECF_NORETURN)))
1828 add_call_clobber_ops (stmt, get_callee_fndecl (expr));
1829 else if (!(call_flags & ECF_CONST))
1830 add_call_read_ops (stmt, get_callee_fndecl (expr));
1833 /* Find uses in the called function. */
1834 get_expr_operands (stmt, &CALL_EXPR_FN (expr), opf_use);
1835 nargs = call_expr_nargs (expr);
1836 for (i = 0; i < nargs; i++)
1837 get_expr_operands (stmt, &CALL_EXPR_ARG (expr, i), opf_use);
1839 get_expr_operands (stmt, &CALL_EXPR_STATIC_CHAIN (expr), opf_use);
1843 /* Scan operands in the ASM_EXPR stmt referred to in INFO. */
1846 get_asm_expr_operands (tree stmt)
1850 const char **oconstraints;
1851 const char *constraint;
1852 bool allows_mem, allows_reg, is_inout;
1855 s_ann = stmt_ann (stmt);
1856 noutputs = list_length (ASM_OUTPUTS (stmt));
1857 oconstraints = (const char **) alloca ((noutputs) * sizeof (const char *));
1859 /* Gather all output operands. */
1860 for (i = 0, link = ASM_OUTPUTS (stmt); link; i++, link = TREE_CHAIN (link))
1862 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
1863 oconstraints[i] = constraint;
1864 parse_output_constraint (&constraint, i, 0, 0, &allows_mem,
1865 &allows_reg, &is_inout);
1867 /* This should have been split in gimplify_asm_expr. */
1868 gcc_assert (!allows_reg || !is_inout);
1870 /* Memory operands are addressable. Note that STMT needs the
1871 address of this operand. */
1872 if (!allows_reg && allows_mem)
1874 tree t = get_base_address (TREE_VALUE (link));
1875 if (t && DECL_P (t) && s_ann)
1876 add_to_addressable_set (t, &s_ann->addresses_taken);
1879 get_expr_operands (stmt, &TREE_VALUE (link), opf_def);
1882 /* Gather all input operands. */
1883 for (link = ASM_INPUTS (stmt); link; link = TREE_CHAIN (link))
1885 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
1886 parse_input_constraint (&constraint, 0, 0, noutputs, 0, oconstraints,
1887 &allows_mem, &allows_reg);
1889 /* Memory operands are addressable. Note that STMT needs the
1890 address of this operand. */
1891 if (!allows_reg && allows_mem)
1893 tree t = get_base_address (TREE_VALUE (link));
1894 if (t && DECL_P (t) && s_ann)
1895 add_to_addressable_set (t, &s_ann->addresses_taken);
1898 get_expr_operands (stmt, &TREE_VALUE (link), 0);
1901 /* Clobber all memory and addressable symbols for asm ("" : : : "memory"); */
1902 for (link = ASM_CLOBBERS (stmt); link; link = TREE_CHAIN (link))
1903 if (strcmp (TREE_STRING_POINTER (TREE_VALUE (link)), "memory") == 0)
1908 s_ann->references_memory = true;
1910 EXECUTE_IF_SET_IN_BITMAP (gimple_call_clobbered_vars (cfun), 0, i, bi)
1912 tree var = referenced_var (i);
1913 add_stmt_operand (&var, s_ann, opf_def | opf_implicit);
1916 EXECUTE_IF_SET_IN_BITMAP (gimple_addressable_vars (cfun), 0, i, bi)
1918 tree var = referenced_var (i);
1920 /* Subvars are explicitly represented in this list, so we
1921 don't need the original to be added to the clobber ops,
1922 but the original *will* be in this list because we keep
1923 the addressability of the original variable up-to-date
1924 to avoid confusing the back-end. */
1925 if (var_can_have_subvars (var)
1926 && get_subvars_for_var (var) != NULL)
1929 add_stmt_operand (&var, s_ann, opf_def | opf_implicit);
1936 /* Scan operands for the assignment expression EXPR in statement STMT. */
1939 get_modify_stmt_operands (tree stmt, tree expr)
1941 /* First get operands from the RHS. */
1942 get_expr_operands (stmt, &GIMPLE_STMT_OPERAND (expr, 1), opf_use);
1944 /* For the LHS, use a regular definition (opf_def) for GIMPLE
1945 registers. If the LHS is a store to memory, we will need
1946 a preserving definition (VDEF).
1948 Preserving definitions are those that modify a part of an
1949 aggregate object for which no subvars have been computed (or the
1950 reference does not correspond exactly to one of them). Stores
1951 through a pointer are also represented with VDEF operators.
1953 We used to distinguish between preserving and killing definitions.
1954 We always emit preserving definitions now. */
1955 get_expr_operands (stmt, &GIMPLE_STMT_OPERAND (expr, 0), opf_def);
1959 /* Recursively scan the expression pointed to by EXPR_P in statement
1960 STMT. FLAGS is one of the OPF_* constants modifying how to
1961 interpret the operands found. */
1964 get_expr_operands (tree stmt, tree *expr_p, int flags)
1966 enum tree_code code;
1967 enum tree_code_class codeclass;
1968 tree expr = *expr_p;
1969 stmt_ann_t s_ann = stmt_ann (stmt);
1974 code = TREE_CODE (expr);
1975 codeclass = TREE_CODE_CLASS (code);
1980 /* Taking the address of a variable does not represent a
1981 reference to it, but the fact that the statement takes its
1982 address will be of interest to some passes (e.g. alias
1984 add_to_addressable_set (TREE_OPERAND (expr, 0), &s_ann->addresses_taken);
1986 /* If the address is invariant, there may be no interesting
1987 variable references inside. */
1988 if (is_gimple_min_invariant (expr))
1991 /* Otherwise, there may be variables referenced inside but there
1992 should be no VUSEs created, since the referenced objects are
1993 not really accessed. The only operands that we should find
1994 here are ARRAY_REF indices which will always be real operands
1995 (GIMPLE does not allow non-registers as array indices). */
1996 flags |= opf_no_vops;
1997 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2001 case STRUCT_FIELD_TAG:
2002 case SYMBOL_MEMORY_TAG:
2003 case NAME_MEMORY_TAG:
2004 add_stmt_operand (expr_p, s_ann, flags);
2013 /* Add the subvars for a variable, if it has subvars, to DEFS
2014 or USES. Otherwise, add the variable itself. Whether it
2015 goes to USES or DEFS depends on the operand flags. */
2016 if (var_can_have_subvars (expr)
2017 && (svars = get_subvars_for_var (expr)))
2020 for (sv = svars; sv; sv = sv->next)
2021 add_stmt_operand (&sv->var, s_ann, flags);
2024 add_stmt_operand (expr_p, s_ann, flags);
2029 case MISALIGNED_INDIRECT_REF:
2030 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), flags);
2033 case ALIGN_INDIRECT_REF:
2035 get_indirect_ref_operands (stmt, expr, flags, NULL_TREE, 0, -1, true);
2038 case TARGET_MEM_REF:
2039 get_tmr_operands (stmt, expr, flags);
2043 case ARRAY_RANGE_REF:
2049 HOST_WIDE_INT offset, size, maxsize;
2052 /* This component reference becomes an access to all of the
2053 subvariables it can touch, if we can determine that, but
2054 *NOT* the real one. If we can't determine which fields we
2055 could touch, the recursion will eventually get to a
2056 variable and add *all* of its subvars, or whatever is the
2057 minimum correct subset. */
2058 ref = get_ref_base_and_extent (expr, &offset, &size, &maxsize);
2059 if (SSA_VAR_P (ref) && get_subvars_for_var (ref))
2062 subvar_t svars = get_subvars_for_var (ref);
2064 for (sv = svars; sv; sv = sv->next)
2068 if (overlap_subvar (offset, maxsize, sv->var, &exact))
2070 int subvar_flags = flags;
2072 add_stmt_operand (&sv->var, s_ann, subvar_flags);
2077 flags |= opf_no_vops;
2079 if (TREE_THIS_VOLATILE (expr))
2080 get_stmt_ann (stmt)->has_volatile_ops = true;
2082 else if (TREE_CODE (ref) == INDIRECT_REF)
2084 get_indirect_ref_operands (stmt, ref, flags, expr, offset,
2086 flags |= opf_no_vops;
2089 /* Even if we found subvars above we need to ensure to see
2090 immediate uses for d in s.a[d]. In case of s.a having
2091 a subvar or we would miss it otherwise. */
2092 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2094 if (code == COMPONENT_REF)
2096 if (s_ann && TREE_THIS_VOLATILE (TREE_OPERAND (expr, 1)))
2097 s_ann->has_volatile_ops = true;
2098 get_expr_operands (stmt, &TREE_OPERAND (expr, 2), opf_use);
2100 else if (code == ARRAY_REF || code == ARRAY_RANGE_REF)
2102 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), opf_use);
2103 get_expr_operands (stmt, &TREE_OPERAND (expr, 2), opf_use);
2104 get_expr_operands (stmt, &TREE_OPERAND (expr, 3), opf_use);
2110 case WITH_SIZE_EXPR:
2111 /* WITH_SIZE_EXPR is a pass-through reference to its first argument,
2112 and an rvalue reference to its second argument. */
2113 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), opf_use);
2114 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2118 get_call_expr_operands (stmt, expr);
2123 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), opf_use);
2124 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), opf_use);
2125 get_expr_operands (stmt, &TREE_OPERAND (expr, 2), opf_use);
2128 case GIMPLE_MODIFY_STMT:
2129 get_modify_stmt_operands (stmt, expr);
2134 /* General aggregate CONSTRUCTORs have been decomposed, but they
2135 are still in use as the COMPLEX_EXPR equivalent for vectors. */
2136 constructor_elt *ce;
2137 unsigned HOST_WIDE_INT idx;
2140 VEC_iterate (constructor_elt, CONSTRUCTOR_ELTS (expr), idx, ce);
2142 get_expr_operands (stmt, &ce->value, opf_use);
2148 case TRUTH_NOT_EXPR:
2149 case VIEW_CONVERT_EXPR:
2151 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2154 case TRUTH_AND_EXPR:
2156 case TRUTH_XOR_EXPR:
2162 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2163 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), flags);
2168 case REALIGN_LOAD_EXPR:
2170 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2171 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), flags);
2172 get_expr_operands (stmt, &TREE_OPERAND (expr, 2), flags);
2176 case CHANGE_DYNAMIC_TYPE_EXPR:
2177 get_expr_operands (stmt, &CHANGE_DYNAMIC_TYPE_LOCATION (expr), opf_use);
2195 /* Expressions that make no memory references. */
2199 if (codeclass == tcc_unary)
2201 if (codeclass == tcc_binary || codeclass == tcc_comparison)
2203 if (codeclass == tcc_constant || codeclass == tcc_type)
2207 /* If we get here, something has gone wrong. */
2208 #ifdef ENABLE_CHECKING
2209 fprintf (stderr, "unhandled expression in get_expr_operands():\n");
2211 fputs ("\n", stderr);
2217 /* Parse STMT looking for operands. When finished, the various
2218 build_* operand vectors will have potential operands in them. */
2221 parse_ssa_operands (tree stmt)
2223 enum tree_code code;
2225 code = TREE_CODE (stmt);
2228 case GIMPLE_MODIFY_STMT:
2229 get_modify_stmt_operands (stmt, stmt);
2233 get_expr_operands (stmt, &COND_EXPR_COND (stmt), opf_use);
2237 get_expr_operands (stmt, &SWITCH_COND (stmt), opf_use);
2241 get_asm_expr_operands (stmt);
2245 get_expr_operands (stmt, &TREE_OPERAND (stmt, 0), opf_use);
2249 get_expr_operands (stmt, &GOTO_DESTINATION (stmt), opf_use);
2253 get_expr_operands (stmt, &LABEL_EXPR_LABEL (stmt), opf_use);
2257 case CASE_LABEL_EXPR:
2258 case TRY_CATCH_EXPR:
2259 case TRY_FINALLY_EXPR:
2260 case EH_FILTER_EXPR:
2263 /* These nodes contain no variable references. */
2267 /* Notice that if get_expr_operands tries to use &STMT as the
2268 operand pointer (which may only happen for USE operands), we
2269 will fail in add_stmt_operand. This default will handle
2270 statements like empty statements, or CALL_EXPRs that may
2271 appear on the RHS of a statement or as statements themselves. */
2272 get_expr_operands (stmt, &stmt, opf_use);
2278 /* Create an operands cache for STMT. */
2281 build_ssa_operands (tree stmt)
2283 stmt_ann_t ann = get_stmt_ann (stmt);
2285 /* Initially assume that the statement has no volatile operands and
2286 makes no memory references. */
2287 ann->has_volatile_ops = false;
2288 ann->references_memory = false;
2289 /* Just clear the bitmap so we don't end up reallocating it over and over. */
2290 if (ann->addresses_taken)
2291 bitmap_clear (ann->addresses_taken);
2293 start_ssa_stmt_operands ();
2294 parse_ssa_operands (stmt);
2295 operand_build_sort_virtual (build_vuses);
2296 operand_build_sort_virtual (build_vdefs);
2297 finalize_ssa_stmt_operands (stmt);
2299 if (ann->addresses_taken && bitmap_empty_p (ann->addresses_taken))
2300 ann->addresses_taken = NULL;
2301 /* For added safety, assume that statements with volatile operands
2302 also reference memory. */
2303 if (ann->has_volatile_ops)
2304 ann->references_memory = true;
2308 /* Free any operands vectors in OPS. */
2311 free_ssa_operands (stmt_operands_p ops)
2313 ops->def_ops = NULL;
2314 ops->use_ops = NULL;
2315 ops->vdef_ops = NULL;
2316 ops->vuse_ops = NULL;
2317 BITMAP_FREE (ops->loads);
2318 BITMAP_FREE (ops->stores);
2322 /* Get the operands of statement STMT. */
2325 update_stmt_operands (tree stmt)
2327 stmt_ann_t ann = get_stmt_ann (stmt);
2329 /* If update_stmt_operands is called before SSA is initialized, do
2331 if (!ssa_operands_active ())
2334 /* The optimizers cannot handle statements that are nothing but a
2335 _DECL. This indicates a bug in the gimplifier. */
2336 gcc_assert (!SSA_VAR_P (stmt));
2338 timevar_push (TV_TREE_OPS);
2340 gcc_assert (ann->modified);
2341 build_ssa_operands (stmt);
2344 timevar_pop (TV_TREE_OPS);
2348 /* Copies virtual operands from SRC to DST. */
2351 copy_virtual_operands (tree dest, tree src)
2354 voptype_p src_vuses, dest_vuses;
2355 voptype_p src_vdefs, dest_vdefs;
2356 struct voptype_d vuse;
2357 struct voptype_d vdef;
2358 stmt_ann_t dest_ann;
2360 VDEF_OPS (dest) = NULL;
2361 VUSE_OPS (dest) = NULL;
2363 dest_ann = get_stmt_ann (dest);
2364 BITMAP_FREE (dest_ann->operands.loads);
2365 BITMAP_FREE (dest_ann->operands.stores);
2367 if (LOADED_SYMS (src))
2369 dest_ann->operands.loads = BITMAP_ALLOC (&operands_bitmap_obstack);
2370 bitmap_copy (dest_ann->operands.loads, LOADED_SYMS (src));
2373 if (STORED_SYMS (src))
2375 dest_ann->operands.stores = BITMAP_ALLOC (&operands_bitmap_obstack);
2376 bitmap_copy (dest_ann->operands.stores, STORED_SYMS (src));
2379 /* Copy all the VUSE operators and corresponding operands. */
2381 for (src_vuses = VUSE_OPS (src); src_vuses; src_vuses = src_vuses->next)
2383 n = VUSE_NUM (src_vuses);
2384 dest_vuses = add_vuse_op (dest, NULL_TREE, n, dest_vuses);
2385 for (i = 0; i < n; i++)
2386 SET_USE (VUSE_OP_PTR (dest_vuses, i), VUSE_OP (src_vuses, i));
2388 if (VUSE_OPS (dest) == NULL)
2389 VUSE_OPS (dest) = vuse.next;
2392 /* Copy all the VDEF operators and corresponding operands. */
2394 for (src_vdefs = VDEF_OPS (src); src_vdefs; src_vdefs = src_vdefs->next)
2396 n = VUSE_NUM (src_vdefs);
2397 dest_vdefs = add_vdef_op (dest, NULL_TREE, n, dest_vdefs);
2398 VDEF_RESULT (dest_vdefs) = VDEF_RESULT (src_vdefs);
2399 for (i = 0; i < n; i++)
2400 SET_USE (VUSE_OP_PTR (dest_vdefs, i), VUSE_OP (src_vdefs, i));
2402 if (VDEF_OPS (dest) == NULL)
2403 VDEF_OPS (dest) = vdef.next;
2408 /* Specifically for use in DOM's expression analysis. Given a store, we
2409 create an artificial stmt which looks like a load from the store, this can
2410 be used to eliminate redundant loads. OLD_OPS are the operands from the
2411 store stmt, and NEW_STMT is the new load which represents a load of the
2415 create_ssa_artificial_load_stmt (tree new_stmt, tree old_stmt)
2419 use_operand_p use_p;
2422 get_stmt_ann (new_stmt);
2424 /* Process NEW_STMT looking for operands. */
2425 start_ssa_stmt_operands ();
2426 parse_ssa_operands (new_stmt);
2428 for (i = 0; VEC_iterate (tree, build_vuses, i, op); i++)
2429 if (TREE_CODE (op) != SSA_NAME)
2430 var_ann (op)->in_vuse_list = false;
2432 for (i = 0; VEC_iterate (tree, build_vuses, i, op); i++)
2433 if (TREE_CODE (op) != SSA_NAME)
2434 var_ann (op)->in_vdef_list = false;
2436 /* Remove any virtual operands that were found. */
2437 VEC_truncate (tree, build_vdefs, 0);
2438 VEC_truncate (tree, build_vuses, 0);
2440 /* For each VDEF on the original statement, we want to create a
2441 VUSE of the VDEF result operand on the new statement. */
2442 FOR_EACH_SSA_TREE_OPERAND (op, old_stmt, iter, SSA_OP_VDEF)
2445 finalize_ssa_stmt_operands (new_stmt);
2447 /* All uses in this fake stmt must not be in the immediate use lists. */
2448 FOR_EACH_SSA_USE_OPERAND (use_p, new_stmt, iter, SSA_OP_ALL_USES)
2449 delink_imm_use (use_p);
2453 /* Swap operands EXP0 and EXP1 in statement STMT. No attempt is done
2454 to test the validity of the swap operation. */
2457 swap_tree_operands (tree stmt, tree *exp0, tree *exp1)
2463 /* If the operand cache is active, attempt to preserve the relative
2464 positions of these two operands in their respective immediate use
2466 if (ssa_operands_active () && op0 != op1)
2468 use_optype_p use0, use1, ptr;
2471 /* Find the 2 operands in the cache, if they are there. */
2472 for (ptr = USE_OPS (stmt); ptr; ptr = ptr->next)
2473 if (USE_OP_PTR (ptr)->use == exp0)
2479 for (ptr = USE_OPS (stmt); ptr; ptr = ptr->next)
2480 if (USE_OP_PTR (ptr)->use == exp1)
2486 /* If both uses don't have operand entries, there isn't much we can do
2487 at this point. Presumably we don't need to worry about it. */
2490 tree *tmp = USE_OP_PTR (use1)->use;
2491 USE_OP_PTR (use1)->use = USE_OP_PTR (use0)->use;
2492 USE_OP_PTR (use0)->use = tmp;
2496 /* Now swap the data. */
2502 /* Add the base address of REF to the set *ADDRESSES_TAKEN. If
2503 *ADDRESSES_TAKEN is NULL, a new set is created. REF may be
2504 a single variable whose address has been taken or any other valid
2505 GIMPLE memory reference (structure reference, array, etc). If the
2506 base address of REF is a decl that has sub-variables, also add all
2507 of its sub-variables. */
2510 add_to_addressable_set (tree ref, bitmap *addresses_taken)
2515 gcc_assert (addresses_taken);
2517 /* Note that it is *NOT OKAY* to use the target of a COMPONENT_REF
2518 as the only thing we take the address of. If VAR is a structure,
2519 taking the address of a field means that the whole structure may
2520 be referenced using pointer arithmetic. See PR 21407 and the
2521 ensuing mailing list discussion. */
2522 var = get_base_address (ref);
2523 if (var && SSA_VAR_P (var))
2525 if (*addresses_taken == NULL)
2526 *addresses_taken = BITMAP_GGC_ALLOC ();
2528 if (var_can_have_subvars (var)
2529 && (svars = get_subvars_for_var (var)))
2532 for (sv = svars; sv; sv = sv->next)
2534 bitmap_set_bit (*addresses_taken, DECL_UID (sv->var));
2535 TREE_ADDRESSABLE (sv->var) = 1;
2540 bitmap_set_bit (*addresses_taken, DECL_UID (var));
2541 TREE_ADDRESSABLE (var) = 1;
2547 /* Scan the immediate_use list for VAR making sure its linked properly.
2548 Return TRUE if there is a problem and emit an error message to F. */
2551 verify_imm_links (FILE *f, tree var)
2553 use_operand_p ptr, prev, list;
2556 gcc_assert (TREE_CODE (var) == SSA_NAME);
2558 list = &(SSA_NAME_IMM_USE_NODE (var));
2559 gcc_assert (list->use == NULL);
2561 if (list->prev == NULL)
2563 gcc_assert (list->next == NULL);
2569 for (ptr = list->next; ptr != list; )
2571 if (prev != ptr->prev)
2574 if (ptr->use == NULL)
2575 goto error; /* 2 roots, or SAFE guard node. */
2576 else if (*(ptr->use) != var)
2582 /* Avoid infinite loops. 50,000,000 uses probably indicates a
2584 if (count++ > 50000000)
2588 /* Verify list in the other direction. */
2590 for (ptr = list->prev; ptr != list; )
2592 if (prev != ptr->next)
2606 if (ptr->stmt && stmt_modified_p (ptr->stmt))
2608 fprintf (f, " STMT MODIFIED. - <%p> ", (void *)ptr->stmt);
2609 print_generic_stmt (f, ptr->stmt, TDF_SLIM);
2611 fprintf (f, " IMM ERROR : (use_p : tree - %p:%p)", (void *)ptr,
2613 print_generic_expr (f, USE_FROM_PTR (ptr), TDF_SLIM);
2619 /* Dump all the immediate uses to FILE. */
2622 dump_immediate_uses_for (FILE *file, tree var)
2624 imm_use_iterator iter;
2625 use_operand_p use_p;
2627 gcc_assert (var && TREE_CODE (var) == SSA_NAME);
2629 print_generic_expr (file, var, TDF_SLIM);
2630 fprintf (file, " : -->");
2631 if (has_zero_uses (var))
2632 fprintf (file, " no uses.\n");
2634 if (has_single_use (var))
2635 fprintf (file, " single use.\n");
2637 fprintf (file, "%d uses.\n", num_imm_uses (var));
2639 FOR_EACH_IMM_USE_FAST (use_p, iter, var)
2641 if (use_p->stmt == NULL && use_p->use == NULL)
2642 fprintf (file, "***end of stmt iterator marker***\n");
2644 if (!is_gimple_reg (USE_FROM_PTR (use_p)))
2645 print_generic_stmt (file, USE_STMT (use_p), TDF_VOPS|TDF_MEMSYMS);
2647 print_generic_stmt (file, USE_STMT (use_p), TDF_SLIM);
2649 fprintf(file, "\n");
2653 /* Dump all the immediate uses to FILE. */
2656 dump_immediate_uses (FILE *file)
2661 fprintf (file, "Immediate_uses: \n\n");
2662 for (x = 1; x < num_ssa_names; x++)
2667 dump_immediate_uses_for (file, var);
2672 /* Dump def-use edges on stderr. */
2675 debug_immediate_uses (void)
2677 dump_immediate_uses (stderr);
2681 /* Dump def-use edges on stderr. */
2684 debug_immediate_uses_for (tree var)
2686 dump_immediate_uses_for (stderr, var);
2690 /* Create a new change buffer for the statement pointed by STMT_P and
2691 push the buffer into SCB_STACK. Each change buffer
2692 records state information needed to determine what changed in the
2693 statement. Mainly, this keeps track of symbols that may need to be
2694 put into SSA form, SSA name replacements and other information
2695 needed to keep the SSA form up to date. */
2698 push_stmt_changes (tree *stmt_p)
2705 /* It makes no sense to keep track of PHI nodes. */
2706 if (TREE_CODE (stmt) == PHI_NODE)
2709 buf = XNEW (struct scb_d);
2710 memset (buf, 0, sizeof *buf);
2712 buf->stmt_p = stmt_p;
2714 if (stmt_references_memory_p (stmt))
2719 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_VUSE)
2721 tree sym = TREE_CODE (op) == SSA_NAME ? SSA_NAME_VAR (op) : op;
2722 if (buf->loads == NULL)
2723 buf->loads = BITMAP_ALLOC (NULL);
2724 bitmap_set_bit (buf->loads, DECL_UID (sym));
2727 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_VDEF)
2729 tree sym = TREE_CODE (op) == SSA_NAME ? SSA_NAME_VAR (op) : op;
2730 if (buf->stores == NULL)
2731 buf->stores = BITMAP_ALLOC (NULL);
2732 bitmap_set_bit (buf->stores, DECL_UID (sym));
2736 VEC_safe_push (scb_t, heap, scb_stack, buf);
2740 /* Given two sets S1 and S2, mark the symbols that differ in S1 and S2
2741 for renaming. The set to mark for renaming is (S1 & ~S2) | (S2 & ~S1). */
2744 mark_difference_for_renaming (bitmap s1, bitmap s2)
2746 if (s1 == NULL && s2 == NULL)
2749 if (s1 && s2 == NULL)
2750 mark_set_for_renaming (s1);
2751 else if (s1 == NULL && s2)
2752 mark_set_for_renaming (s2);
2753 else if (!bitmap_equal_p (s1, s2))
2755 bitmap t1 = BITMAP_ALLOC (NULL);
2756 bitmap t2 = BITMAP_ALLOC (NULL);
2758 bitmap_and_compl (t1, s1, s2);
2759 bitmap_and_compl (t2, s2, s1);
2760 bitmap_ior_into (t1, t2);
2761 mark_set_for_renaming (t1);
2769 /* Pop the top SCB from SCB_STACK and act on the differences between
2770 what was recorded by push_stmt_changes and the current state of
2774 pop_stmt_changes (tree *stmt_p)
2778 bitmap loads, stores;
2783 /* It makes no sense to keep track of PHI nodes. */
2784 if (TREE_CODE (stmt) == PHI_NODE)
2787 buf = VEC_pop (scb_t, scb_stack);
2788 gcc_assert (stmt_p == buf->stmt_p);
2790 /* Force an operand re-scan on the statement and mark any newly
2791 exposed variables. */
2794 /* Determine whether any memory symbols need to be renamed. If the
2795 sets of loads and stores are different after the statement is
2796 modified, then the affected symbols need to be renamed.
2798 Note that it may be possible for the statement to not reference
2799 memory anymore, but we still need to act on the differences in
2800 the sets of symbols. */
2801 loads = stores = NULL;
2802 if (stmt_references_memory_p (stmt))
2807 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_VUSE)
2809 tree sym = TREE_CODE (op) == SSA_NAME ? SSA_NAME_VAR (op) : op;
2811 loads = BITMAP_ALLOC (NULL);
2812 bitmap_set_bit (loads, DECL_UID (sym));
2815 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_VDEF)
2817 tree sym = TREE_CODE (op) == SSA_NAME ? SSA_NAME_VAR (op) : op;
2819 stores = BITMAP_ALLOC (NULL);
2820 bitmap_set_bit (stores, DECL_UID (sym));
2824 /* If LOADS is different from BUF->LOADS, the affected
2825 symbols need to be marked for renaming. */
2826 mark_difference_for_renaming (loads, buf->loads);
2828 /* Similarly for STORES and BUF->STORES. */
2829 mark_difference_for_renaming (stores, buf->stores);
2831 /* Mark all the naked GIMPLE register operands for renaming. */
2832 FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_DEF|SSA_OP_USE)
2834 mark_sym_for_renaming (op);
2836 /* FIXME, need to add more finalizers here. Cleanup EH info,
2837 recompute invariants for address expressions, add
2838 SSA replacement mappings, etc. For instance, given
2839 testsuite/gcc.c-torture/compile/pr16808.c, we fold a statement of
2842 # SMT.4_20 = VDEF <SMT.4_16>
2845 So, the VDEF will disappear, but instead of marking SMT.4 for
2846 renaming it would be far more efficient to establish a
2847 replacement mapping that would replace every reference of
2848 SMT.4_20 with SMT.4_16. */
2850 /* Free memory used by the buffer. */
2851 BITMAP_FREE (buf->loads);
2852 BITMAP_FREE (buf->stores);
2853 BITMAP_FREE (loads);
2854 BITMAP_FREE (stores);
2860 /* Discard the topmost change buffer from SCB_STACK. This is useful
2861 when the caller realized that it did not actually modified the
2862 statement. It avoids the expensive operand re-scan. */
2865 discard_stmt_changes (tree *stmt_p)
2870 /* It makes no sense to keep track of PHI nodes. */
2872 if (TREE_CODE (stmt) == PHI_NODE)
2875 buf = VEC_pop (scb_t, scb_stack);
2876 gcc_assert (stmt_p == buf->stmt_p);
2878 /* Free memory used by the buffer. */
2879 BITMAP_FREE (buf->loads);
2880 BITMAP_FREE (buf->stores);
2886 /* Returns true if statement STMT may access memory. */
2889 stmt_references_memory_p (tree stmt)
2891 if (!gimple_ssa_operands (cfun)->ops_active || TREE_CODE (stmt) == PHI_NODE)
2894 return stmt_ann (stmt)->references_memory;