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.
1186 XXX: We should handle the NO_ALIAS attributes here. */
1189 access_can_touch_variable (tree ref, tree alias, HOST_WIDE_INT offset,
1192 bool offsetgtz = offset > 0;
1193 unsigned HOST_WIDE_INT uoffset = (unsigned HOST_WIDE_INT) offset;
1194 tree base = ref ? get_base_address (ref) : NULL;
1196 /* If ALIAS is .GLOBAL_VAR then the memory reference REF must be
1197 using a call-clobbered memory tag. By definition, call-clobbered
1198 memory tags can always touch .GLOBAL_VAR. */
1199 if (alias == gimple_global_var (cfun))
1202 /* If ref is a TARGET_MEM_REF, just return true, as we can't really
1203 disambiguate them right now. */
1204 if (ref && TREE_CODE (ref) == TARGET_MEM_REF)
1207 /* If ALIAS is an SFT, it can't be touched if the offset
1208 and size of the access is not overlapping with the SFT offset and
1209 size. This is only true if we are accessing through a pointer
1210 to a type that is the same as SFT_PARENT_VAR. Otherwise, we may
1211 be accessing through a pointer to some substruct of the
1212 structure, and if we try to prune there, we will have the wrong
1213 offset, and get the wrong answer.
1214 i.e., we can't prune without more work if we have something like
1220 const char *byte_op;
1228 foo = &targetm.asm_out.aligned_op;
1231 SFT.1, which represents hi, will have SFT_OFFSET=32 because in
1232 terms of SFT_PARENT_VAR, that is where it is.
1233 However, the access through the foo pointer will be at offset 0. */
1235 && TREE_CODE (alias) == STRUCT_FIELD_TAG
1237 && TREE_TYPE (base) == TREE_TYPE (SFT_PARENT_VAR (alias))
1238 && !overlap_subvar (offset, size, alias, NULL))
1240 #ifdef ACCESS_DEBUGGING
1241 fprintf (stderr, "Access to ");
1242 print_generic_expr (stderr, ref, 0);
1243 fprintf (stderr, " may not touch ");
1244 print_generic_expr (stderr, alias, 0);
1245 fprintf (stderr, " in function %s\n", get_name (current_function_decl));
1250 /* Without strict aliasing, it is impossible for a component access
1251 through a pointer to touch a random variable, unless that
1252 variable *is* a structure or a pointer.
1254 That is, given p->c, and some random global variable b,
1255 there is no legal way that p->c could be an access to b.
1257 Without strict aliasing on, we consider it legal to do something
1260 struct foos { int l; };
1262 static struct foos *getfoo(void);
1265 struct foos *f = getfoo();
1272 static struct foos *getfoo(void)
1273 { return (struct foos *)&foo; }
1275 (taken from 20000623-1.c)
1277 The docs also say/imply that access through union pointers
1278 is legal (but *not* if you take the address of the union member,
1279 i.e. the inverse), such that you can do
1289 U *pretmp = (U*)&rv;
1293 To implement this, we just punt on accesses through union
1297 && flag_strict_aliasing
1298 && TREE_CODE (ref) != INDIRECT_REF
1301 && (TREE_CODE (base) != INDIRECT_REF
1302 || TREE_CODE (TREE_TYPE (base)) != UNION_TYPE)
1303 && !AGGREGATE_TYPE_P (TREE_TYPE (alias))
1304 && TREE_CODE (TREE_TYPE (alias)) != COMPLEX_TYPE
1305 && !var_ann (alias)->is_heapvar
1306 /* When the struct has may_alias attached to it, we need not to
1308 && get_alias_set (base))
1310 #ifdef ACCESS_DEBUGGING
1311 fprintf (stderr, "Access to ");
1312 print_generic_expr (stderr, ref, 0);
1313 fprintf (stderr, " may not touch ");
1314 print_generic_expr (stderr, alias, 0);
1315 fprintf (stderr, " in function %s\n", get_name (current_function_decl));
1320 /* If the offset of the access is greater than the size of one of
1321 the possible aliases, it can't be touching that alias, because it
1322 would be past the end of the structure. */
1324 && flag_strict_aliasing
1325 && TREE_CODE (ref) != INDIRECT_REF
1327 && !POINTER_TYPE_P (TREE_TYPE (alias))
1329 && DECL_SIZE (alias)
1330 && TREE_CODE (DECL_SIZE (alias)) == INTEGER_CST
1331 && uoffset > TREE_INT_CST_LOW (DECL_SIZE (alias)))
1333 #ifdef ACCESS_DEBUGGING
1334 fprintf (stderr, "Access to ");
1335 print_generic_expr (stderr, ref, 0);
1336 fprintf (stderr, " may not touch ");
1337 print_generic_expr (stderr, alias, 0);
1338 fprintf (stderr, " in function %s\n", get_name (current_function_decl));
1346 /* Add the actual variables FULL_REF can access, given a member of
1347 full_ref's points-to set VAR, where FULL_REF is an access of SIZE at
1348 OFFSET from var. IS_CALL_SITE is true if this is a call, and IS_DEF
1349 is true if this is supposed to be a vdef, and false if this should
1352 The real purpose of this function is to take a points-to set for a
1353 pointer to a structure, say
1358 } foo, *foop = &foo;
1360 and discover which variables an access, such as foop->b, can alias.
1362 This is necessary because foop only actually points to foo's first
1363 member, so that is all the points-to set contains. However, an access
1364 to foop->a may be touching some single SFT if we have created some
1365 SFT's for a structure. */
1368 add_vars_for_offset (tree full_ref, tree var, HOST_WIDE_INT offset,
1369 HOST_WIDE_INT size, bool is_call_site, bool is_def)
1371 /* Call-clobbered tags may have non-call-clobbered
1372 symbols in their alias sets. Ignore them if we are
1373 adding VOPs for a call site. */
1374 if (is_call_site && !is_call_clobbered (var))
1377 /* For offset 0, we already have the right variable. If there is no
1378 full_ref, this is not a place we care about (All component
1379 related accesses that go through pointers will have full_ref not
1381 Any var for which we didn't create SFT's can't be
1383 if (!full_ref || (offset == 0 && size != -1)
1384 || (TREE_CODE (var) != STRUCT_FIELD_TAG
1385 && (!var_can_have_subvars (var) || !get_subvars_for_var (var))))
1387 if (!access_can_touch_variable (full_ref, var, offset, size))
1396 else if (TREE_CODE (var) == STRUCT_FIELD_TAG)
1401 subvar_t sv = get_subvars_for_var (SFT_PARENT_VAR (var));
1402 for (; sv; sv = sv->next)
1404 if (overlap_subvar (SFT_OFFSET (var) + offset, size,
1406 && access_can_touch_variable (full_ref, sv->var,
1411 append_vdef (sv->var);
1413 append_vuse (sv->var);
1421 subvar_t sv = get_subvars_for_var (SFT_PARENT_VAR (var));
1422 for (; sv; sv = sv->next)
1424 /* Once we hit the end of the parts that could touch,
1426 if (SFT_OFFSET (var) + offset + size <= SFT_OFFSET (sv->var))
1428 if (overlap_subvar (SFT_OFFSET (var) + offset, size,
1430 && access_can_touch_variable (full_ref, sv->var, offset,
1435 append_vdef (sv->var);
1437 append_vuse (sv->var);
1447 /* Add VAR to the virtual operands array. FLAGS is as in
1448 get_expr_operands. FULL_REF is a tree that contains the entire
1449 pointer dereference expression, if available, or NULL otherwise.
1450 OFFSET and SIZE come from the memory access expression that
1451 generated this virtual operand. IS_CALL_SITE is true if the
1452 affected statement is a call site. */
1455 add_virtual_operand (tree var, stmt_ann_t s_ann, int flags,
1456 tree full_ref, HOST_WIDE_INT offset,
1457 HOST_WIDE_INT size, bool is_call_site)
1459 bitmap aliases = NULL;
1463 sym = (TREE_CODE (var) == SSA_NAME ? SSA_NAME_VAR (var) : var);
1464 v_ann = var_ann (sym);
1466 /* Mark the statement as having memory operands. */
1467 s_ann->references_memory = true;
1469 /* Mark statements with volatile operands. Optimizers should back
1470 off from statements having volatile operands. */
1471 if (TREE_THIS_VOLATILE (sym) && s_ann)
1472 s_ann->has_volatile_ops = true;
1474 /* If the variable cannot be modified and this is a VDEF change
1475 it into a VUSE. This happens when read-only variables are marked
1476 call-clobbered and/or aliased to writable variables. So we only
1477 check that this only happens on non-specific stores.
1479 Note that if this is a specific store, i.e. associated with a
1480 GIMPLE_MODIFY_STMT, then we can't suppress the VDEF, lest we run
1481 into validation problems.
1483 This can happen when programs cast away const, leaving us with a
1484 store to read-only memory. If the statement is actually executed
1485 at runtime, then the program is ill formed. If the statement is
1486 not executed then all is well. At the very least, we cannot ICE. */
1487 if ((flags & opf_implicit) && unmodifiable_var_p (var))
1490 /* The variable is not a GIMPLE register. Add it (or its aliases) to
1491 virtual operands, unless the caller has specifically requested
1492 not to add virtual operands (used when adding operands inside an
1493 ADDR_EXPR expression). */
1494 if (flags & opf_no_vops)
1498 aliases = MTAG_ALIASES (var);
1500 if (aliases == NULL)
1502 if (s_ann && !gimple_aliases_computed_p (cfun))
1503 s_ann->has_volatile_ops = true;
1505 /* The variable is not aliased or it is an alias tag. */
1506 if (flags & opf_def)
1517 /* The variable is aliased. Add its aliases to the virtual
1519 gcc_assert (!bitmap_empty_p (aliases));
1521 if (flags & opf_def)
1523 bool none_added = true;
1524 EXECUTE_IF_SET_IN_BITMAP (aliases, 0, i, bi)
1526 al = referenced_var (i);
1527 none_added &= !add_vars_for_offset (full_ref, al, offset, size,
1528 is_call_site, true);
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 bool none_added = true;
1550 EXECUTE_IF_SET_IN_BITMAP (aliases, 0, i, bi)
1552 al = referenced_var (i);
1553 none_added &= !add_vars_for_offset (full_ref, al, offset, size,
1554 is_call_site, false);
1558 /* Even if no aliases have been added, we still need to
1559 establish def-use and use-def chains, lest
1560 transformations think that this is not a memory
1561 reference. For an example of this scenario, see
1562 testsuite/g++.dg/opt/cleanup1.C. */
1570 /* Add *VAR_P to the appropriate operand array for S_ANN. FLAGS is as in
1571 get_expr_operands. If *VAR_P is a GIMPLE register, it will be added to
1572 the statement's real operands, otherwise it is added to virtual
1576 add_stmt_operand (tree *var_p, stmt_ann_t s_ann, int flags)
1581 gcc_assert (SSA_VAR_P (*var_p) && s_ann);
1584 sym = (TREE_CODE (var) == SSA_NAME ? SSA_NAME_VAR (var) : var);
1585 v_ann = var_ann (sym);
1587 /* Mark statements with volatile operands. */
1588 if (TREE_THIS_VOLATILE (sym))
1589 s_ann->has_volatile_ops = true;
1591 if (is_gimple_reg (sym))
1593 /* The variable is a GIMPLE register. Add it to real operands. */
1594 if (flags & opf_def)
1600 add_virtual_operand (var, s_ann, flags, NULL_TREE, 0, -1, false);
1604 /* A subroutine of get_expr_operands to handle INDIRECT_REF,
1605 ALIGN_INDIRECT_REF and MISALIGNED_INDIRECT_REF.
1607 STMT is the statement being processed, EXPR is the INDIRECT_REF
1610 FLAGS is as in get_expr_operands.
1612 FULL_REF contains the full pointer dereference expression, if we
1613 have it, or NULL otherwise.
1615 OFFSET and SIZE are the location of the access inside the
1616 dereferenced pointer, if known.
1618 RECURSE_ON_BASE should be set to true if we want to continue
1619 calling get_expr_operands on the base pointer, and false if
1620 something else will do it for us. */
1623 get_indirect_ref_operands (tree stmt, tree expr, int flags,
1625 HOST_WIDE_INT offset, HOST_WIDE_INT size,
1626 bool recurse_on_base)
1628 tree *pptr = &TREE_OPERAND (expr, 0);
1630 stmt_ann_t s_ann = stmt_ann (stmt);
1632 s_ann->references_memory = true;
1633 if (s_ann && TREE_THIS_VOLATILE (expr))
1634 s_ann->has_volatile_ops = true;
1636 if (SSA_VAR_P (ptr))
1638 struct ptr_info_def *pi = NULL;
1640 /* If PTR has flow-sensitive points-to information, use it. */
1641 if (TREE_CODE (ptr) == SSA_NAME
1642 && (pi = SSA_NAME_PTR_INFO (ptr)) != NULL
1643 && pi->name_mem_tag)
1645 /* PTR has its own memory tag. Use it. */
1646 add_virtual_operand (pi->name_mem_tag, s_ann, flags,
1647 full_ref, offset, size, false);
1651 /* If PTR is not an SSA_NAME or it doesn't have a name
1652 tag, use its symbol memory tag. */
1655 /* If we are emitting debugging dumps, display a warning if
1656 PTR is an SSA_NAME with no flow-sensitive alias
1657 information. That means that we may need to compute
1660 && TREE_CODE (ptr) == SSA_NAME
1664 "NOTE: no flow-sensitive alias info for ");
1665 print_generic_expr (dump_file, ptr, dump_flags);
1666 fprintf (dump_file, " in ");
1667 print_generic_stmt (dump_file, stmt, dump_flags);
1670 if (TREE_CODE (ptr) == SSA_NAME)
1671 ptr = SSA_NAME_VAR (ptr);
1672 v_ann = var_ann (ptr);
1674 if (v_ann->symbol_mem_tag)
1675 add_virtual_operand (v_ann->symbol_mem_tag, s_ann, flags,
1676 full_ref, offset, size, false);
1678 /* Aliasing information is missing; mark statement as
1679 volatile so we won't optimize it out too actively. */
1681 && !gimple_aliases_computed_p (cfun)
1682 && (flags & opf_def))
1683 s_ann->has_volatile_ops = true;
1686 else if (TREE_CODE (ptr) == INTEGER_CST)
1688 /* If a constant is used as a pointer, we can't generate a real
1689 operand for it but we mark the statement volatile to prevent
1690 optimizations from messing things up. */
1692 s_ann->has_volatile_ops = true;
1697 /* Ok, this isn't even is_gimple_min_invariant. Something's broke. */
1701 /* If requested, add a USE operand for the base pointer. */
1702 if (recurse_on_base)
1703 get_expr_operands (stmt, pptr, opf_use);
1707 /* A subroutine of get_expr_operands to handle TARGET_MEM_REF. */
1710 get_tmr_operands (tree stmt, tree expr, int flags)
1713 stmt_ann_t s_ann = stmt_ann (stmt);
1715 /* This statement references memory. */
1716 s_ann->references_memory = 1;
1718 /* First record the real operands. */
1719 get_expr_operands (stmt, &TMR_BASE (expr), opf_use);
1720 get_expr_operands (stmt, &TMR_INDEX (expr), opf_use);
1722 if (TMR_SYMBOL (expr))
1723 add_to_addressable_set (TMR_SYMBOL (expr), &s_ann->addresses_taken);
1725 tag = TMR_TAG (expr);
1728 /* Something weird, so ensure that we will be careful. */
1729 s_ann->has_volatile_ops = true;
1734 get_expr_operands (stmt, &tag, flags);
1738 add_virtual_operand (tag, s_ann, flags, expr, 0, -1, false);
1742 /* Add clobbering definitions for .GLOBAL_VAR or for each of the call
1743 clobbered variables in the function. */
1746 add_call_clobber_ops (tree stmt, tree callee)
1750 stmt_ann_t s_ann = stmt_ann (stmt);
1751 bitmap not_read_b, not_written_b;
1753 /* If we created .GLOBAL_VAR earlier, just use it. */
1754 if (gimple_global_var (cfun))
1756 tree var = gimple_global_var (cfun);
1757 add_virtual_operand (var, s_ann, opf_def, NULL, 0, -1, true);
1761 /* Get info for local and module level statics. There is a bit
1762 set for each static if the call being processed does not read
1763 or write that variable. */
1764 not_read_b = callee ? ipa_reference_get_not_read_global (callee) : NULL;
1765 not_written_b = callee ? ipa_reference_get_not_written_global (callee) : NULL;
1767 /* Add a VDEF operand for every call clobbered variable. */
1768 EXECUTE_IF_SET_IN_BITMAP (gimple_call_clobbered_vars (cfun), 0, u, bi)
1770 tree var = referenced_var_lookup (u);
1771 unsigned int escape_mask = var_ann (var)->escape_mask;
1772 tree real_var = var;
1776 /* Not read and not written are computed on regular vars, not
1777 subvars, so look at the parent var if this is an SFT. */
1778 if (TREE_CODE (var) == STRUCT_FIELD_TAG)
1779 real_var = SFT_PARENT_VAR (var);
1781 not_read = not_read_b
1782 ? bitmap_bit_p (not_read_b, DECL_UID (real_var))
1785 not_written = not_written_b
1786 ? bitmap_bit_p (not_written_b, DECL_UID (real_var))
1788 gcc_assert (!unmodifiable_var_p (var));
1790 clobber_stats.clobbered_vars++;
1792 /* See if this variable is really clobbered by this function. */
1794 /* Trivial case: Things escaping only to pure/const are not
1795 clobbered by non-pure-const, and only read by pure/const. */
1796 if ((escape_mask & ~(ESCAPE_TO_PURE_CONST)) == 0)
1798 tree call = get_call_expr_in (stmt);
1799 if (call_expr_flags (call) & (ECF_CONST | ECF_PURE))
1801 add_virtual_operand (var, s_ann, opf_use, NULL, 0, -1, true);
1802 clobber_stats.unescapable_clobbers_avoided++;
1807 clobber_stats.unescapable_clobbers_avoided++;
1814 clobber_stats.static_write_clobbers_avoided++;
1816 add_virtual_operand (var, s_ann, opf_use, NULL, 0, -1, true);
1818 clobber_stats.static_read_clobbers_avoided++;
1821 add_virtual_operand (var, s_ann, opf_def, NULL, 0, -1, true);
1826 /* Add VUSE operands for .GLOBAL_VAR or all call clobbered variables in the
1830 add_call_read_ops (tree stmt, tree callee)
1834 stmt_ann_t s_ann = stmt_ann (stmt);
1837 /* if the function is not pure, it may reference memory. Add
1838 a VUSE for .GLOBAL_VAR if it has been created. See add_referenced_var
1839 for the heuristic used to decide whether to create .GLOBAL_VAR. */
1840 if (gimple_global_var (cfun))
1842 tree var = gimple_global_var (cfun);
1843 add_virtual_operand (var, s_ann, opf_use, NULL, 0, -1, true);
1847 not_read_b = callee ? ipa_reference_get_not_read_global (callee) : NULL;
1849 /* Add a VUSE for each call-clobbered variable. */
1850 EXECUTE_IF_SET_IN_BITMAP (gimple_call_clobbered_vars (cfun), 0, u, bi)
1852 tree var = referenced_var (u);
1853 tree real_var = var;
1856 clobber_stats.readonly_clobbers++;
1858 /* Not read and not written are computed on regular vars, not
1859 subvars, so look at the parent var if this is an SFT. */
1861 if (TREE_CODE (var) == STRUCT_FIELD_TAG)
1862 real_var = SFT_PARENT_VAR (var);
1864 not_read = not_read_b ? bitmap_bit_p (not_read_b, DECL_UID (real_var))
1869 clobber_stats.static_readonly_clobbers_avoided++;
1873 add_virtual_operand (var, s_ann, opf_use, NULL, 0, -1, true);
1878 /* A subroutine of get_expr_operands to handle CALL_EXPR. */
1881 get_call_expr_operands (tree stmt, tree expr)
1883 int call_flags = call_expr_flags (expr);
1885 stmt_ann_t ann = stmt_ann (stmt);
1887 ann->references_memory = true;
1889 /* If aliases have been computed already, add VDEF or VUSE
1890 operands for all the symbols that have been found to be
1892 if (gimple_aliases_computed_p (cfun)
1893 && !(call_flags & ECF_NOVOPS))
1895 /* A 'pure' or a 'const' function never call-clobbers anything.
1896 A 'noreturn' function might, but since we don't return anyway
1897 there is no point in recording that. */
1898 if (TREE_SIDE_EFFECTS (expr)
1899 && !(call_flags & (ECF_PURE | ECF_CONST | ECF_NORETURN)))
1900 add_call_clobber_ops (stmt, get_callee_fndecl (expr));
1901 else if (!(call_flags & ECF_CONST))
1902 add_call_read_ops (stmt, get_callee_fndecl (expr));
1905 /* Find uses in the called function. */
1906 get_expr_operands (stmt, &CALL_EXPR_FN (expr), opf_use);
1907 nargs = call_expr_nargs (expr);
1908 for (i = 0; i < nargs; i++)
1909 get_expr_operands (stmt, &CALL_EXPR_ARG (expr, i), opf_use);
1911 get_expr_operands (stmt, &CALL_EXPR_STATIC_CHAIN (expr), opf_use);
1915 /* Scan operands in the ASM_EXPR stmt referred to in INFO. */
1918 get_asm_expr_operands (tree stmt)
1922 const char **oconstraints;
1923 const char *constraint;
1924 bool allows_mem, allows_reg, is_inout;
1927 s_ann = stmt_ann (stmt);
1928 noutputs = list_length (ASM_OUTPUTS (stmt));
1929 oconstraints = (const char **) alloca ((noutputs) * sizeof (const char *));
1931 /* Gather all output operands. */
1932 for (i = 0, link = ASM_OUTPUTS (stmt); link; i++, link = TREE_CHAIN (link))
1934 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
1935 oconstraints[i] = constraint;
1936 parse_output_constraint (&constraint, i, 0, 0, &allows_mem,
1937 &allows_reg, &is_inout);
1939 /* This should have been split in gimplify_asm_expr. */
1940 gcc_assert (!allows_reg || !is_inout);
1942 /* Memory operands are addressable. Note that STMT needs the
1943 address of this operand. */
1944 if (!allows_reg && allows_mem)
1946 tree t = get_base_address (TREE_VALUE (link));
1947 if (t && DECL_P (t) && s_ann)
1948 add_to_addressable_set (t, &s_ann->addresses_taken);
1951 get_expr_operands (stmt, &TREE_VALUE (link), opf_def);
1954 /* Gather all input operands. */
1955 for (link = ASM_INPUTS (stmt); link; link = TREE_CHAIN (link))
1957 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
1958 parse_input_constraint (&constraint, 0, 0, noutputs, 0, oconstraints,
1959 &allows_mem, &allows_reg);
1961 /* Memory operands are addressable. Note that STMT needs the
1962 address of this operand. */
1963 if (!allows_reg && allows_mem)
1965 tree t = get_base_address (TREE_VALUE (link));
1966 if (t && DECL_P (t) && s_ann)
1967 add_to_addressable_set (t, &s_ann->addresses_taken);
1970 get_expr_operands (stmt, &TREE_VALUE (link), 0);
1973 /* Clobber all memory and addressable symbols for asm ("" : : : "memory"); */
1974 for (link = ASM_CLOBBERS (stmt); link; link = TREE_CHAIN (link))
1975 if (strcmp (TREE_STRING_POINTER (TREE_VALUE (link)), "memory") == 0)
1980 s_ann->references_memory = true;
1982 EXECUTE_IF_SET_IN_BITMAP (gimple_call_clobbered_vars (cfun), 0, i, bi)
1984 tree var = referenced_var (i);
1985 add_stmt_operand (&var, s_ann, opf_def | opf_implicit);
1988 EXECUTE_IF_SET_IN_BITMAP (gimple_addressable_vars (cfun), 0, i, bi)
1990 tree var = referenced_var (i);
1992 /* Subvars are explicitly represented in this list, so we
1993 don't need the original to be added to the clobber ops,
1994 but the original *will* be in this list because we keep
1995 the addressability of the original variable up-to-date
1996 to avoid confusing the back-end. */
1997 if (var_can_have_subvars (var)
1998 && get_subvars_for_var (var) != NULL)
2001 add_stmt_operand (&var, s_ann, opf_def | opf_implicit);
2008 /* Scan operands for the assignment expression EXPR in statement STMT. */
2011 get_modify_stmt_operands (tree stmt, tree expr)
2013 /* First get operands from the RHS. */
2014 get_expr_operands (stmt, &GIMPLE_STMT_OPERAND (expr, 1), opf_use);
2016 /* For the LHS, use a regular definition (opf_def) for GIMPLE
2017 registers. If the LHS is a store to memory, we will need
2018 a preserving definition (VDEF).
2020 Preserving definitions are those that modify a part of an
2021 aggregate object for which no subvars have been computed (or the
2022 reference does not correspond exactly to one of them). Stores
2023 through a pointer are also represented with VDEF operators.
2025 We used to distinguish between preserving and killing definitions.
2026 We always emit preserving definitions now. */
2027 get_expr_operands (stmt, &GIMPLE_STMT_OPERAND (expr, 0), opf_def);
2031 /* Recursively scan the expression pointed to by EXPR_P in statement
2032 STMT. FLAGS is one of the OPF_* constants modifying how to
2033 interpret the operands found. */
2036 get_expr_operands (tree stmt, tree *expr_p, int flags)
2038 enum tree_code code;
2039 enum tree_code_class codeclass;
2040 tree expr = *expr_p;
2041 stmt_ann_t s_ann = stmt_ann (stmt);
2046 code = TREE_CODE (expr);
2047 codeclass = TREE_CODE_CLASS (code);
2052 /* Taking the address of a variable does not represent a
2053 reference to it, but the fact that the statement takes its
2054 address will be of interest to some passes (e.g. alias
2056 add_to_addressable_set (TREE_OPERAND (expr, 0), &s_ann->addresses_taken);
2058 /* If the address is invariant, there may be no interesting
2059 variable references inside. */
2060 if (is_gimple_min_invariant (expr))
2063 /* Otherwise, there may be variables referenced inside but there
2064 should be no VUSEs created, since the referenced objects are
2065 not really accessed. The only operands that we should find
2066 here are ARRAY_REF indices which will always be real operands
2067 (GIMPLE does not allow non-registers as array indices). */
2068 flags |= opf_no_vops;
2069 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2073 case STRUCT_FIELD_TAG:
2074 case SYMBOL_MEMORY_TAG:
2075 case NAME_MEMORY_TAG:
2076 add_stmt_operand (expr_p, s_ann, flags);
2085 /* Add the subvars for a variable, if it has subvars, to DEFS
2086 or USES. Otherwise, add the variable itself. Whether it
2087 goes to USES or DEFS depends on the operand flags. */
2088 if (var_can_have_subvars (expr)
2089 && (svars = get_subvars_for_var (expr)))
2092 for (sv = svars; sv; sv = sv->next)
2093 add_stmt_operand (&sv->var, s_ann, flags);
2096 add_stmt_operand (expr_p, s_ann, flags);
2101 case MISALIGNED_INDIRECT_REF:
2102 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), flags);
2105 case ALIGN_INDIRECT_REF:
2107 get_indirect_ref_operands (stmt, expr, flags, expr, 0, -1, true);
2110 case TARGET_MEM_REF:
2111 get_tmr_operands (stmt, expr, flags);
2115 case ARRAY_RANGE_REF:
2121 HOST_WIDE_INT offset, size, maxsize;
2124 /* This component reference becomes an access to all of the
2125 subvariables it can touch, if we can determine that, but
2126 *NOT* the real one. If we can't determine which fields we
2127 could touch, the recursion will eventually get to a
2128 variable and add *all* of its subvars, or whatever is the
2129 minimum correct subset. */
2130 ref = get_ref_base_and_extent (expr, &offset, &size, &maxsize);
2131 if (SSA_VAR_P (ref) && get_subvars_for_var (ref))
2134 subvar_t svars = get_subvars_for_var (ref);
2136 for (sv = svars; sv; sv = sv->next)
2140 if (overlap_subvar (offset, maxsize, sv->var, &exact))
2142 int subvar_flags = flags;
2144 add_stmt_operand (&sv->var, s_ann, subvar_flags);
2149 flags |= opf_no_vops;
2151 if (TREE_THIS_VOLATILE (expr))
2152 get_stmt_ann (stmt)->has_volatile_ops = true;
2154 else if (TREE_CODE (ref) == INDIRECT_REF)
2156 get_indirect_ref_operands (stmt, ref, flags, expr, offset,
2158 flags |= opf_no_vops;
2161 /* Even if we found subvars above we need to ensure to see
2162 immediate uses for d in s.a[d]. In case of s.a having
2163 a subvar or we would miss it otherwise. */
2164 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2166 if (code == COMPONENT_REF)
2168 if (s_ann && TREE_THIS_VOLATILE (TREE_OPERAND (expr, 1)))
2169 s_ann->has_volatile_ops = true;
2170 get_expr_operands (stmt, &TREE_OPERAND (expr, 2), opf_use);
2172 else if (code == ARRAY_REF || code == ARRAY_RANGE_REF)
2174 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), opf_use);
2175 get_expr_operands (stmt, &TREE_OPERAND (expr, 2), opf_use);
2176 get_expr_operands (stmt, &TREE_OPERAND (expr, 3), opf_use);
2182 case WITH_SIZE_EXPR:
2183 /* WITH_SIZE_EXPR is a pass-through reference to its first argument,
2184 and an rvalue reference to its second argument. */
2185 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), opf_use);
2186 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2190 get_call_expr_operands (stmt, expr);
2195 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), opf_use);
2196 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), opf_use);
2197 get_expr_operands (stmt, &TREE_OPERAND (expr, 2), opf_use);
2200 case GIMPLE_MODIFY_STMT:
2201 get_modify_stmt_operands (stmt, expr);
2206 /* General aggregate CONSTRUCTORs have been decomposed, but they
2207 are still in use as the COMPLEX_EXPR equivalent for vectors. */
2208 constructor_elt *ce;
2209 unsigned HOST_WIDE_INT idx;
2212 VEC_iterate (constructor_elt, CONSTRUCTOR_ELTS (expr), idx, ce);
2214 get_expr_operands (stmt, &ce->value, opf_use);
2220 case TRUTH_NOT_EXPR:
2221 case VIEW_CONVERT_EXPR:
2223 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2226 case TRUTH_AND_EXPR:
2228 case TRUTH_XOR_EXPR:
2234 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2235 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), flags);
2240 case REALIGN_LOAD_EXPR:
2242 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2243 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), flags);
2244 get_expr_operands (stmt, &TREE_OPERAND (expr, 2), flags);
2248 case CHANGE_DYNAMIC_TYPE_EXPR:
2249 get_expr_operands (stmt, &CHANGE_DYNAMIC_TYPE_LOCATION (expr), opf_use);
2267 /* Expressions that make no memory references. */
2271 if (codeclass == tcc_unary)
2273 if (codeclass == tcc_binary || codeclass == tcc_comparison)
2275 if (codeclass == tcc_constant || codeclass == tcc_type)
2279 /* If we get here, something has gone wrong. */
2280 #ifdef ENABLE_CHECKING
2281 fprintf (stderr, "unhandled expression in get_expr_operands():\n");
2283 fputs ("\n", stderr);
2289 /* Parse STMT looking for operands. When finished, the various
2290 build_* operand vectors will have potential operands in them. */
2293 parse_ssa_operands (tree stmt)
2295 enum tree_code code;
2297 code = TREE_CODE (stmt);
2300 case GIMPLE_MODIFY_STMT:
2301 get_modify_stmt_operands (stmt, stmt);
2305 get_expr_operands (stmt, &COND_EXPR_COND (stmt), opf_use);
2309 get_expr_operands (stmt, &SWITCH_COND (stmt), opf_use);
2313 get_asm_expr_operands (stmt);
2317 get_expr_operands (stmt, &TREE_OPERAND (stmt, 0), opf_use);
2321 get_expr_operands (stmt, &GOTO_DESTINATION (stmt), opf_use);
2325 get_expr_operands (stmt, &LABEL_EXPR_LABEL (stmt), opf_use);
2329 case CASE_LABEL_EXPR:
2330 case TRY_CATCH_EXPR:
2331 case TRY_FINALLY_EXPR:
2332 case EH_FILTER_EXPR:
2335 /* These nodes contain no variable references. */
2339 /* Notice that if get_expr_operands tries to use &STMT as the
2340 operand pointer (which may only happen for USE operands), we
2341 will fail in add_stmt_operand. This default will handle
2342 statements like empty statements, or CALL_EXPRs that may
2343 appear on the RHS of a statement or as statements themselves. */
2344 get_expr_operands (stmt, &stmt, opf_use);
2350 /* Create an operands cache for STMT. */
2353 build_ssa_operands (tree stmt)
2355 stmt_ann_t ann = get_stmt_ann (stmt);
2357 /* Initially assume that the statement has no volatile operands and
2358 makes no memory references. */
2359 ann->has_volatile_ops = false;
2360 ann->references_memory = false;
2361 /* Just clear the bitmap so we don't end up reallocating it over and over. */
2362 if (ann->addresses_taken)
2363 bitmap_clear (ann->addresses_taken);
2365 start_ssa_stmt_operands ();
2366 parse_ssa_operands (stmt);
2367 operand_build_sort_virtual (build_vuses);
2368 operand_build_sort_virtual (build_vdefs);
2369 finalize_ssa_stmt_operands (stmt);
2371 if (ann->addresses_taken && bitmap_empty_p (ann->addresses_taken))
2372 ann->addresses_taken = NULL;
2373 /* For added safety, assume that statements with volatile operands
2374 also reference memory. */
2375 if (ann->has_volatile_ops)
2376 ann->references_memory = true;
2380 /* Free any operands vectors in OPS. */
2383 free_ssa_operands (stmt_operands_p ops)
2385 ops->def_ops = NULL;
2386 ops->use_ops = NULL;
2387 ops->vdef_ops = NULL;
2388 ops->vuse_ops = NULL;
2389 BITMAP_FREE (ops->loads);
2390 BITMAP_FREE (ops->stores);
2394 /* Get the operands of statement STMT. */
2397 update_stmt_operands (tree stmt)
2399 stmt_ann_t ann = get_stmt_ann (stmt);
2401 /* If update_stmt_operands is called before SSA is initialized, do
2403 if (!ssa_operands_active ())
2406 /* The optimizers cannot handle statements that are nothing but a
2407 _DECL. This indicates a bug in the gimplifier. */
2408 gcc_assert (!SSA_VAR_P (stmt));
2410 timevar_push (TV_TREE_OPS);
2412 gcc_assert (ann->modified);
2413 build_ssa_operands (stmt);
2416 timevar_pop (TV_TREE_OPS);
2420 /* Copies virtual operands from SRC to DST. */
2423 copy_virtual_operands (tree dest, tree src)
2426 voptype_p src_vuses, dest_vuses;
2427 voptype_p src_vdefs, dest_vdefs;
2428 struct voptype_d vuse;
2429 struct voptype_d vdef;
2430 stmt_ann_t dest_ann;
2432 VDEF_OPS (dest) = NULL;
2433 VUSE_OPS (dest) = NULL;
2435 dest_ann = get_stmt_ann (dest);
2436 BITMAP_FREE (dest_ann->operands.loads);
2437 BITMAP_FREE (dest_ann->operands.stores);
2439 if (LOADED_SYMS (src))
2441 dest_ann->operands.loads = BITMAP_ALLOC (&operands_bitmap_obstack);
2442 bitmap_copy (dest_ann->operands.loads, LOADED_SYMS (src));
2445 if (STORED_SYMS (src))
2447 dest_ann->operands.stores = BITMAP_ALLOC (&operands_bitmap_obstack);
2448 bitmap_copy (dest_ann->operands.stores, STORED_SYMS (src));
2451 /* Copy all the VUSE operators and corresponding operands. */
2453 for (src_vuses = VUSE_OPS (src); src_vuses; src_vuses = src_vuses->next)
2455 n = VUSE_NUM (src_vuses);
2456 dest_vuses = add_vuse_op (dest, NULL_TREE, n, dest_vuses);
2457 for (i = 0; i < n; i++)
2458 SET_USE (VUSE_OP_PTR (dest_vuses, i), VUSE_OP (src_vuses, i));
2460 if (VUSE_OPS (dest) == NULL)
2461 VUSE_OPS (dest) = vuse.next;
2464 /* Copy all the VDEF operators and corresponding operands. */
2466 for (src_vdefs = VDEF_OPS (src); src_vdefs; src_vdefs = src_vdefs->next)
2468 n = VUSE_NUM (src_vdefs);
2469 dest_vdefs = add_vdef_op (dest, NULL_TREE, n, dest_vdefs);
2470 VDEF_RESULT (dest_vdefs) = VDEF_RESULT (src_vdefs);
2471 for (i = 0; i < n; i++)
2472 SET_USE (VUSE_OP_PTR (dest_vdefs, i), VUSE_OP (src_vdefs, i));
2474 if (VDEF_OPS (dest) == NULL)
2475 VDEF_OPS (dest) = vdef.next;
2480 /* Specifically for use in DOM's expression analysis. Given a store, we
2481 create an artificial stmt which looks like a load from the store, this can
2482 be used to eliminate redundant loads. OLD_OPS are the operands from the
2483 store stmt, and NEW_STMT is the new load which represents a load of the
2487 create_ssa_artificial_load_stmt (tree new_stmt, tree old_stmt)
2491 use_operand_p use_p;
2494 get_stmt_ann (new_stmt);
2496 /* Process NEW_STMT looking for operands. */
2497 start_ssa_stmt_operands ();
2498 parse_ssa_operands (new_stmt);
2500 for (i = 0; VEC_iterate (tree, build_vuses, i, op); i++)
2501 if (TREE_CODE (op) != SSA_NAME)
2502 var_ann (op)->in_vuse_list = false;
2504 for (i = 0; VEC_iterate (tree, build_vuses, i, op); i++)
2505 if (TREE_CODE (op) != SSA_NAME)
2506 var_ann (op)->in_vdef_list = false;
2508 /* Remove any virtual operands that were found. */
2509 VEC_truncate (tree, build_vdefs, 0);
2510 VEC_truncate (tree, build_vuses, 0);
2512 /* For each VDEF on the original statement, we want to create a
2513 VUSE of the VDEF result operand on the new statement. */
2514 FOR_EACH_SSA_TREE_OPERAND (op, old_stmt, iter, SSA_OP_VDEF)
2517 finalize_ssa_stmt_operands (new_stmt);
2519 /* All uses in this fake stmt must not be in the immediate use lists. */
2520 FOR_EACH_SSA_USE_OPERAND (use_p, new_stmt, iter, SSA_OP_ALL_USES)
2521 delink_imm_use (use_p);
2525 /* Swap operands EXP0 and EXP1 in statement STMT. No attempt is done
2526 to test the validity of the swap operation. */
2529 swap_tree_operands (tree stmt, tree *exp0, tree *exp1)
2535 /* If the operand cache is active, attempt to preserve the relative
2536 positions of these two operands in their respective immediate use
2538 if (ssa_operands_active () && op0 != op1)
2540 use_optype_p use0, use1, ptr;
2543 /* Find the 2 operands in the cache, if they are there. */
2544 for (ptr = USE_OPS (stmt); ptr; ptr = ptr->next)
2545 if (USE_OP_PTR (ptr)->use == exp0)
2551 for (ptr = USE_OPS (stmt); ptr; ptr = ptr->next)
2552 if (USE_OP_PTR (ptr)->use == exp1)
2558 /* If both uses don't have operand entries, there isn't much we can do
2559 at this point. Presumably we don't need to worry about it. */
2562 tree *tmp = USE_OP_PTR (use1)->use;
2563 USE_OP_PTR (use1)->use = USE_OP_PTR (use0)->use;
2564 USE_OP_PTR (use0)->use = tmp;
2568 /* Now swap the data. */
2574 /* Add the base address of REF to the set *ADDRESSES_TAKEN. If
2575 *ADDRESSES_TAKEN is NULL, a new set is created. REF may be
2576 a single variable whose address has been taken or any other valid
2577 GIMPLE memory reference (structure reference, array, etc). If the
2578 base address of REF is a decl that has sub-variables, also add all
2579 of its sub-variables. */
2582 add_to_addressable_set (tree ref, bitmap *addresses_taken)
2587 gcc_assert (addresses_taken);
2589 /* Note that it is *NOT OKAY* to use the target of a COMPONENT_REF
2590 as the only thing we take the address of. If VAR is a structure,
2591 taking the address of a field means that the whole structure may
2592 be referenced using pointer arithmetic. See PR 21407 and the
2593 ensuing mailing list discussion. */
2594 var = get_base_address (ref);
2595 if (var && SSA_VAR_P (var))
2597 if (*addresses_taken == NULL)
2598 *addresses_taken = BITMAP_GGC_ALLOC ();
2600 if (var_can_have_subvars (var)
2601 && (svars = get_subvars_for_var (var)))
2604 for (sv = svars; sv; sv = sv->next)
2606 bitmap_set_bit (*addresses_taken, DECL_UID (sv->var));
2607 TREE_ADDRESSABLE (sv->var) = 1;
2612 bitmap_set_bit (*addresses_taken, DECL_UID (var));
2613 TREE_ADDRESSABLE (var) = 1;
2619 /* Scan the immediate_use list for VAR making sure its linked properly.
2620 Return TRUE if there is a problem and emit an error message to F. */
2623 verify_imm_links (FILE *f, tree var)
2625 use_operand_p ptr, prev, list;
2628 gcc_assert (TREE_CODE (var) == SSA_NAME);
2630 list = &(SSA_NAME_IMM_USE_NODE (var));
2631 gcc_assert (list->use == NULL);
2633 if (list->prev == NULL)
2635 gcc_assert (list->next == NULL);
2641 for (ptr = list->next; ptr != list; )
2643 if (prev != ptr->prev)
2646 if (ptr->use == NULL)
2647 goto error; /* 2 roots, or SAFE guard node. */
2648 else if (*(ptr->use) != var)
2654 /* Avoid infinite loops. 50,000,000 uses probably indicates a
2656 if (count++ > 50000000)
2660 /* Verify list in the other direction. */
2662 for (ptr = list->prev; ptr != list; )
2664 if (prev != ptr->next)
2678 if (ptr->stmt && stmt_modified_p (ptr->stmt))
2680 fprintf (f, " STMT MODIFIED. - <%p> ", (void *)ptr->stmt);
2681 print_generic_stmt (f, ptr->stmt, TDF_SLIM);
2683 fprintf (f, " IMM ERROR : (use_p : tree - %p:%p)", (void *)ptr,
2685 print_generic_expr (f, USE_FROM_PTR (ptr), TDF_SLIM);
2691 /* Dump all the immediate uses to FILE. */
2694 dump_immediate_uses_for (FILE *file, tree var)
2696 imm_use_iterator iter;
2697 use_operand_p use_p;
2699 gcc_assert (var && TREE_CODE (var) == SSA_NAME);
2701 print_generic_expr (file, var, TDF_SLIM);
2702 fprintf (file, " : -->");
2703 if (has_zero_uses (var))
2704 fprintf (file, " no uses.\n");
2706 if (has_single_use (var))
2707 fprintf (file, " single use.\n");
2709 fprintf (file, "%d uses.\n", num_imm_uses (var));
2711 FOR_EACH_IMM_USE_FAST (use_p, iter, var)
2713 if (use_p->stmt == NULL && use_p->use == NULL)
2714 fprintf (file, "***end of stmt iterator marker***\n");
2716 if (!is_gimple_reg (USE_FROM_PTR (use_p)))
2717 print_generic_stmt (file, USE_STMT (use_p), TDF_VOPS|TDF_MEMSYMS);
2719 print_generic_stmt (file, USE_STMT (use_p), TDF_SLIM);
2721 fprintf(file, "\n");
2725 /* Dump all the immediate uses to FILE. */
2728 dump_immediate_uses (FILE *file)
2733 fprintf (file, "Immediate_uses: \n\n");
2734 for (x = 1; x < num_ssa_names; x++)
2739 dump_immediate_uses_for (file, var);
2744 /* Dump def-use edges on stderr. */
2747 debug_immediate_uses (void)
2749 dump_immediate_uses (stderr);
2753 /* Dump def-use edges on stderr. */
2756 debug_immediate_uses_for (tree var)
2758 dump_immediate_uses_for (stderr, var);
2762 /* Create a new change buffer for the statement pointed by STMT_P and
2763 push the buffer into SCB_STACK. Each change buffer
2764 records state information needed to determine what changed in the
2765 statement. Mainly, this keeps track of symbols that may need to be
2766 put into SSA form, SSA name replacements and other information
2767 needed to keep the SSA form up to date. */
2770 push_stmt_changes (tree *stmt_p)
2777 /* It makes no sense to keep track of PHI nodes. */
2778 if (TREE_CODE (stmt) == PHI_NODE)
2781 buf = XNEW (struct scb_d);
2782 memset (buf, 0, sizeof *buf);
2784 buf->stmt_p = stmt_p;
2786 if (stmt_references_memory_p (stmt))
2791 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_VUSE)
2793 tree sym = TREE_CODE (op) == SSA_NAME ? SSA_NAME_VAR (op) : op;
2794 if (buf->loads == NULL)
2795 buf->loads = BITMAP_ALLOC (NULL);
2796 bitmap_set_bit (buf->loads, DECL_UID (sym));
2799 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_VDEF)
2801 tree sym = TREE_CODE (op) == SSA_NAME ? SSA_NAME_VAR (op) : op;
2802 if (buf->stores == NULL)
2803 buf->stores = BITMAP_ALLOC (NULL);
2804 bitmap_set_bit (buf->stores, DECL_UID (sym));
2808 VEC_safe_push (scb_t, heap, scb_stack, buf);
2812 /* Given two sets S1 and S2, mark the symbols that differ in S1 and S2
2813 for renaming. The set to mark for renaming is (S1 & ~S2) | (S2 & ~S1). */
2816 mark_difference_for_renaming (bitmap s1, bitmap s2)
2818 if (s1 == NULL && s2 == NULL)
2821 if (s1 && s2 == NULL)
2822 mark_set_for_renaming (s1);
2823 else if (s1 == NULL && s2)
2824 mark_set_for_renaming (s2);
2825 else if (!bitmap_equal_p (s1, s2))
2827 bitmap t1 = BITMAP_ALLOC (NULL);
2828 bitmap t2 = BITMAP_ALLOC (NULL);
2830 bitmap_and_compl (t1, s1, s2);
2831 bitmap_and_compl (t2, s2, s1);
2832 bitmap_ior_into (t1, t2);
2833 mark_set_for_renaming (t1);
2841 /* Pop the top SCB from SCB_STACK and act on the differences between
2842 what was recorded by push_stmt_changes and the current state of
2846 pop_stmt_changes (tree *stmt_p)
2850 bitmap loads, stores;
2855 /* It makes no sense to keep track of PHI nodes. */
2856 if (TREE_CODE (stmt) == PHI_NODE)
2859 buf = VEC_pop (scb_t, scb_stack);
2860 gcc_assert (stmt_p == buf->stmt_p);
2862 /* Force an operand re-scan on the statement and mark any newly
2863 exposed variables. */
2866 /* Determine whether any memory symbols need to be renamed. If the
2867 sets of loads and stores are different after the statement is
2868 modified, then the affected symbols need to be renamed.
2870 Note that it may be possible for the statement to not reference
2871 memory anymore, but we still need to act on the differences in
2872 the sets of symbols. */
2873 loads = stores = NULL;
2874 if (stmt_references_memory_p (stmt))
2879 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_VUSE)
2881 tree sym = TREE_CODE (op) == SSA_NAME ? SSA_NAME_VAR (op) : op;
2883 loads = BITMAP_ALLOC (NULL);
2884 bitmap_set_bit (loads, DECL_UID (sym));
2887 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_VDEF)
2889 tree sym = TREE_CODE (op) == SSA_NAME ? SSA_NAME_VAR (op) : op;
2891 stores = BITMAP_ALLOC (NULL);
2892 bitmap_set_bit (stores, DECL_UID (sym));
2896 /* If LOADS is different from BUF->LOADS, the affected
2897 symbols need to be marked for renaming. */
2898 mark_difference_for_renaming (loads, buf->loads);
2900 /* Similarly for STORES and BUF->STORES. */
2901 mark_difference_for_renaming (stores, buf->stores);
2903 /* Mark all the naked GIMPLE register operands for renaming. */
2904 FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_DEF|SSA_OP_USE)
2906 mark_sym_for_renaming (op);
2908 /* FIXME, need to add more finalizers here. Cleanup EH info,
2909 recompute invariants for address expressions, add
2910 SSA replacement mappings, etc. For instance, given
2911 testsuite/gcc.c-torture/compile/pr16808.c, we fold a statement of
2914 # SMT.4_20 = VDEF <SMT.4_16>
2917 So, the VDEF will disappear, but instead of marking SMT.4 for
2918 renaming it would be far more efficient to establish a
2919 replacement mapping that would replace every reference of
2920 SMT.4_20 with SMT.4_16. */
2922 /* Free memory used by the buffer. */
2923 BITMAP_FREE (buf->loads);
2924 BITMAP_FREE (buf->stores);
2925 BITMAP_FREE (loads);
2926 BITMAP_FREE (stores);
2932 /* Discard the topmost change buffer from SCB_STACK. This is useful
2933 when the caller realized that it did not actually modified the
2934 statement. It avoids the expensive operand re-scan. */
2937 discard_stmt_changes (tree *stmt_p)
2942 /* It makes no sense to keep track of PHI nodes. */
2944 if (TREE_CODE (stmt) == PHI_NODE)
2947 buf = VEC_pop (scb_t, scb_stack);
2948 gcc_assert (stmt_p == buf->stmt_p);
2950 /* Free memory used by the buffer. */
2951 BITMAP_FREE (buf->loads);
2952 BITMAP_FREE (buf->stores);
2958 /* Returns true if statement STMT may access memory. */
2961 stmt_references_memory_p (tree stmt)
2963 if (!gimple_ssa_operands (cfun)->ops_active || TREE_CODE (stmt) == PHI_NODE)
2966 return stmt_ann (stmt)->references_memory;