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
74 operand vector for VUSE, then the new vector will also be modified
75 such that it contains 'a_5' rather than 'a'. */
78 /* Structure storing statistics on how many call clobbers we have, and
79 how many where avoided. */
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
619 initialized to OP and are linked into the immediate uses for STMT.
620 The new vop is appended after PREV. */
622 static inline voptype_p
623 add_vop (tree stmt, tree op, int num, voptype_p prev)
628 new_vop = alloc_vop (num);
629 for (x = 0; x < num; x++)
631 VUSE_OP_PTR (new_vop, x)->prev = NULL;
632 SET_VUSE_OP (new_vop, x, op);
633 VUSE_OP_PTR (new_vop, x)->use = &new_vop->usev.uses[x].use_var;
634 link_imm_use_stmt (VUSE_OP_PTR (new_vop, x),
635 new_vop->usev.uses[x].use_var, stmt);
639 prev->next = new_vop;
640 new_vop->next = NULL;
645 /* Adds OP to the list of vuses of statement STMT after LAST, and moves
646 LAST to the new element. */
648 static inline voptype_p
649 add_vuse_op (tree stmt, tree op, int num, voptype_p last)
651 voptype_p new_vop = add_vop (stmt, op, num, last);
652 VDEF_RESULT (new_vop) = NULL_TREE;
657 /* Adds OP to the list of vdefs of statement STMT after LAST, and moves
658 LAST to the new element. */
660 static inline voptype_p
661 add_vdef_op (tree stmt, tree op, int num, voptype_p last)
663 voptype_p new_vop = add_vop (stmt, op, num, last);
664 VDEF_RESULT (new_vop) = op;
669 /* Takes elements from build_defs and turns them into def operands of STMT.
670 TODO -- Make build_defs VEC of tree *. */
673 finalize_ssa_defs (tree stmt)
676 struct def_optype_d new_list;
677 def_optype_p old_ops, last;
678 unsigned int num = VEC_length (tree, build_defs);
680 /* There should only be a single real definition per assignment. */
681 gcc_assert ((stmt && TREE_CODE (stmt) != GIMPLE_MODIFY_STMT) || num <= 1);
683 new_list.next = NULL;
686 old_ops = DEF_OPS (stmt);
690 /* Check for the common case of 1 def that hasn't changed. */
691 if (old_ops && old_ops->next == NULL && num == 1
692 && (tree *) VEC_index (tree, build_defs, 0) == DEF_OP_PTR (old_ops))
695 /* If there is anything in the old list, free it. */
698 old_ops->next = gimple_ssa_operands (cfun)->free_defs;
699 gimple_ssa_operands (cfun)->free_defs = old_ops;
702 /* If there is anything remaining in the build_defs list, simply emit it. */
703 for ( ; new_i < num; new_i++)
704 last = add_def_op ((tree *) VEC_index (tree, build_defs, new_i), last);
706 /* Now set the stmt's operands. */
707 DEF_OPS (stmt) = new_list.next;
709 #ifdef ENABLE_CHECKING
713 for (ptr = DEF_OPS (stmt); ptr; ptr = ptr->next)
716 gcc_assert (x == num);
722 /* Takes elements from build_uses and turns them into use operands of STMT.
723 TODO -- Make build_uses VEC of tree *. */
726 finalize_ssa_uses (tree stmt)
729 struct use_optype_d new_list;
730 use_optype_p old_ops, ptr, last;
732 #ifdef ENABLE_CHECKING
735 unsigned num = VEC_length (tree, build_uses);
737 /* If the pointer to the operand is the statement itself, something is
738 wrong. It means that we are pointing to a local variable (the
739 initial call to update_stmt_operands does not pass a pointer to a
741 for (x = 0; x < num; x++)
742 gcc_assert (*((tree *)VEC_index (tree, build_uses, x)) != stmt);
746 new_list.next = NULL;
749 old_ops = USE_OPS (stmt);
751 /* If there is anything in the old list, free it. */
754 for (ptr = old_ops; ptr; ptr = ptr->next)
755 delink_imm_use (USE_OP_PTR (ptr));
756 old_ops->next = gimple_ssa_operands (cfun)->free_uses;
757 gimple_ssa_operands (cfun)->free_uses = old_ops;
760 /* Now create nodes for all the new nodes. */
761 for (new_i = 0; new_i < VEC_length (tree, build_uses); new_i++)
762 last = add_use_op (stmt,
763 (tree *) VEC_index (tree, build_uses, new_i),
766 /* Now set the stmt's operands. */
767 USE_OPS (stmt) = new_list.next;
769 #ifdef ENABLE_CHECKING
772 for (ptr = USE_OPS (stmt); ptr; ptr = ptr->next)
775 gcc_assert (x == VEC_length (tree, build_uses));
781 /* Takes elements from BUILD_VDEFS and turns them into vdef operands of
782 STMT. FIXME, for now VDEF operators should have a single operand
786 finalize_ssa_vdefs (tree stmt)
789 struct voptype_d new_list;
790 voptype_p old_ops, ptr, last;
791 stmt_ann_t ann = stmt_ann (stmt);
793 /* Set the symbols referenced by STMT. */
794 if (!bitmap_empty_p (build_stores))
796 if (ann->operands.stores == NULL)
797 ann->operands.stores = BITMAP_ALLOC (&operands_bitmap_obstack);
799 bitmap_copy (ann->operands.stores, build_stores);
802 BITMAP_FREE (ann->operands.stores);
804 /* If aliases have not been computed, do not instantiate a virtual
805 operator on STMT. Initially, we only compute the SSA form on
806 GIMPLE registers. The virtual SSA form is only computed after
807 alias analysis, so virtual operators will remain unrenamed and
808 the verifier will complain. However, alias analysis needs to
809 access symbol load/store information, so we need to compute
811 if (!gimple_aliases_computed_p (cfun))
814 new_list.next = NULL;
817 old_ops = VDEF_OPS (stmt);
819 while (old_ops && new_i < VEC_length (tree, build_vdefs))
821 tree op = VEC_index (tree, build_vdefs, new_i);
822 unsigned new_uid = get_name_decl (op);
823 unsigned old_uid = get_name_decl (VDEF_RESULT (old_ops));
825 /* FIXME, for now each VDEF operator should have at most one
826 operand in their RHS. */
827 gcc_assert (VDEF_NUM (old_ops) == 1);
829 if (old_uid == new_uid)
831 /* If the symbols are the same, reuse the existing operand. */
832 last->next = old_ops;
834 old_ops = old_ops->next;
836 set_virtual_use_link (VDEF_OP_PTR (last, 0), stmt);
839 else if (old_uid < new_uid)
841 /* If old is less than new, old goes to the free list. */
843 delink_imm_use (VDEF_OP_PTR (old_ops, 0));
844 next = old_ops->next;
845 add_vop_to_freelist (old_ops);
850 /* This is a new operand. */
851 last = add_vdef_op (stmt, op, 1, last);
856 /* If there is anything remaining in BUILD_VDEFS, simply emit it. */
857 for ( ; new_i < VEC_length (tree, build_vdefs); new_i++)
858 last = add_vdef_op (stmt, VEC_index (tree, build_vdefs, new_i), 1, last);
860 /* If there is anything in the old list, free it. */
863 for (ptr = old_ops; ptr; ptr = last)
866 delink_imm_use (VDEF_OP_PTR (ptr, 0));
867 add_vop_to_freelist (ptr);
871 /* Now set STMT's operands. */
872 VDEF_OPS (stmt) = new_list.next;
874 #ifdef ENABLE_CHECKING
877 for (ptr = VDEF_OPS (stmt); ptr; ptr = ptr->next)
880 gcc_assert (x == VEC_length (tree, build_vdefs));
886 /* Takes elements from BUILD_VUSES and turns them into VUSE operands of
890 finalize_ssa_vuse_ops (tree stmt)
892 unsigned new_i, old_i;
893 voptype_p old_ops, last;
894 VEC(tree,heap) *new_ops;
897 /* Set the symbols referenced by STMT. */
898 ann = stmt_ann (stmt);
899 if (!bitmap_empty_p (build_loads))
901 if (ann->operands.loads == NULL)
902 ann->operands.loads = BITMAP_ALLOC (&operands_bitmap_obstack);
904 bitmap_copy (ann->operands.loads, build_loads);
907 BITMAP_FREE (ann->operands.loads);
909 /* If aliases have not been computed, do not instantiate a virtual
910 operator on STMT. Initially, we only compute the SSA form on
911 GIMPLE registers. The virtual SSA form is only computed after
912 alias analysis, so virtual operators will remain unrenamed and
913 the verifier will complain. However, alias analysis needs to
914 access symbol load/store information, so we need to compute
916 if (!gimple_aliases_computed_p (cfun))
919 /* STMT should have at most one VUSE operator. */
920 old_ops = VUSE_OPS (stmt);
921 gcc_assert (old_ops == NULL || old_ops->next == NULL);
926 && old_i < VUSE_NUM (old_ops)
927 && new_i < VEC_length (tree, build_vuses))
929 tree new_op = VEC_index (tree, build_vuses, new_i);
930 tree old_op = VUSE_OP (old_ops, old_i);
931 unsigned new_uid = get_name_decl (new_op);
932 unsigned old_uid = get_name_decl (old_op);
934 if (old_uid == new_uid)
936 /* If the symbols are the same, reuse the existing operand. */
937 VEC_safe_push (tree, heap, new_ops, old_op);
941 else if (old_uid < new_uid)
943 /* If OLD_UID is less than NEW_UID, the old operand has
944 disappeared, skip to the next old operand. */
949 /* This is a new operand. */
950 VEC_safe_push (tree, heap, new_ops, new_op);
955 /* If there is anything remaining in the build_vuses list, simply emit it. */
956 for ( ; new_i < VEC_length (tree, build_vuses); new_i++)
957 VEC_safe_push (tree, heap, new_ops, VEC_index (tree, build_vuses, new_i));
959 /* If there is anything in the old list, free it. */
962 for (old_i = 0; old_i < VUSE_NUM (old_ops); old_i++)
963 delink_imm_use (VUSE_OP_PTR (old_ops, old_i));
964 add_vop_to_freelist (old_ops);
965 VUSE_OPS (stmt) = NULL;
968 /* If there are any operands, instantiate a VUSE operator for STMT. */
974 last = add_vuse_op (stmt, NULL, VEC_length (tree, new_ops), NULL);
976 for (i = 0; VEC_iterate (tree, new_ops, i, op); i++)
977 SET_USE (VUSE_OP_PTR (last, (int) i), op);
979 VUSE_OPS (stmt) = last;
980 VEC_free (tree, heap, new_ops);
983 #ifdef ENABLE_CHECKING
989 gcc_assert (VUSE_OPS (stmt)->next == NULL);
990 x = VUSE_NUM (VUSE_OPS (stmt));
995 gcc_assert (x == VEC_length (tree, build_vuses));
1000 /* Return a new VUSE operand vector for STMT. */
1003 finalize_ssa_vuses (tree stmt)
1005 unsigned num, num_vdefs;
1006 unsigned vuse_index;
1008 /* Remove superfluous VUSE operands. If the statement already has a
1009 VDEF operator for a variable 'a', then a VUSE for 'a' is not
1010 needed because VDEFs imply a VUSE of the variable. For instance,
1011 suppose that variable 'a' is pointed-to by p and q:
1017 The VUSE <a_2> is superfluous because it is implied by the
1019 num = VEC_length (tree, build_vuses);
1020 num_vdefs = VEC_length (tree, build_vdefs);
1022 if (num > 0 && num_vdefs > 0)
1023 for (vuse_index = 0; vuse_index < VEC_length (tree, build_vuses); )
1026 vuse = VEC_index (tree, build_vuses, vuse_index);
1027 if (TREE_CODE (vuse) != SSA_NAME)
1029 var_ann_t ann = var_ann (vuse);
1030 ann->in_vuse_list = 0;
1031 if (ann->in_vdef_list)
1033 VEC_ordered_remove (tree, build_vuses, vuse_index);
1040 finalize_ssa_vuse_ops (stmt);
1044 /* Clear the in_list bits and empty the build array for VDEFs and
1048 cleanup_build_arrays (void)
1053 for (i = 0; VEC_iterate (tree, build_vdefs, i, t); i++)
1054 if (TREE_CODE (t) != SSA_NAME)
1055 var_ann (t)->in_vdef_list = false;
1057 for (i = 0; VEC_iterate (tree, build_vuses, i, t); i++)
1058 if (TREE_CODE (t) != SSA_NAME)
1059 var_ann (t)->in_vuse_list = false;
1061 VEC_truncate (tree, build_vdefs, 0);
1062 VEC_truncate (tree, build_vuses, 0);
1063 VEC_truncate (tree, build_defs, 0);
1064 VEC_truncate (tree, build_uses, 0);
1065 bitmap_clear (build_loads);
1066 bitmap_clear (build_stores);
1070 /* Finalize all the build vectors, fill the new ones into INFO. */
1073 finalize_ssa_stmt_operands (tree stmt)
1075 finalize_ssa_defs (stmt);
1076 finalize_ssa_uses (stmt);
1077 finalize_ssa_vdefs (stmt);
1078 finalize_ssa_vuses (stmt);
1079 cleanup_build_arrays ();
1083 /* Start the process of building up operands vectors in INFO. */
1086 start_ssa_stmt_operands (void)
1088 gcc_assert (VEC_length (tree, build_defs) == 0);
1089 gcc_assert (VEC_length (tree, build_uses) == 0);
1090 gcc_assert (VEC_length (tree, build_vuses) == 0);
1091 gcc_assert (VEC_length (tree, build_vdefs) == 0);
1092 gcc_assert (bitmap_empty_p (build_loads));
1093 gcc_assert (bitmap_empty_p (build_stores));
1097 /* Add DEF_P to the list of pointers to operands. */
1100 append_def (tree *def_p)
1102 VEC_safe_push (tree, heap, build_defs, (tree) def_p);
1106 /* Add USE_P to the list of pointers to operands. */
1109 append_use (tree *use_p)
1111 VEC_safe_push (tree, heap, build_uses, (tree) use_p);
1115 /* Add VAR to the set of variables that require a VDEF operator. */
1118 append_vdef (tree var)
1122 if (TREE_CODE (var) != SSA_NAME)
1127 /* If VAR belongs to a memory partition, use it instead of VAR. */
1128 mpt = memory_partition (var);
1132 /* Don't allow duplicate entries. */
1133 ann = get_var_ann (var);
1134 if (ann->in_vdef_list)
1137 ann->in_vdef_list = true;
1141 sym = SSA_NAME_VAR (var);
1143 VEC_safe_push (tree, heap, build_vdefs, var);
1144 bitmap_set_bit (build_stores, DECL_UID (sym));
1148 /* Add VAR to the set of variables that require a VUSE operator. */
1151 append_vuse (tree var)
1155 if (TREE_CODE (var) != SSA_NAME)
1160 /* If VAR belongs to a memory partition, use it instead of VAR. */
1161 mpt = memory_partition (var);
1165 /* Don't allow duplicate entries. */
1166 ann = get_var_ann (var);
1167 if (ann->in_vuse_list)
1169 else if (ann->in_vdef_list)
1171 /* We don't want a vuse if we already have a vdef, but we must
1172 still put this in build_loads. */
1173 bitmap_set_bit (build_loads, DECL_UID (var));
1177 ann->in_vuse_list = true;
1181 sym = SSA_NAME_VAR (var);
1183 VEC_safe_push (tree, heap, build_vuses, var);
1184 bitmap_set_bit (build_loads, DECL_UID (sym));
1188 /* REF is a tree that contains the entire pointer dereference
1189 expression, if available, or NULL otherwise. ALIAS is the variable
1190 we are asking if REF can access. OFFSET and SIZE come from the
1191 memory access expression that generated this virtual operand.
1193 XXX: We should handle the NO_ALIAS attributes here. */
1196 access_can_touch_variable (tree ref, tree alias, HOST_WIDE_INT offset,
1199 bool offsetgtz = offset > 0;
1200 unsigned HOST_WIDE_INT uoffset = (unsigned HOST_WIDE_INT) offset;
1201 tree base = ref ? get_base_address (ref) : NULL;
1203 /* If ALIAS is .GLOBAL_VAR then the memory reference REF must be
1204 using a call-clobbered memory tag. By definition, call-clobbered
1205 memory tags can always touch .GLOBAL_VAR. */
1206 if (alias == gimple_global_var (cfun))
1209 /* If ref is a TARGET_MEM_REF, just return true, as we can't really
1210 disambiguate them right now. */
1211 if (ref && TREE_CODE (ref) == TARGET_MEM_REF)
1214 /* If ALIAS is an SFT, it can't be touched if the offset
1215 and size of the access is not overlapping with the SFT offset and
1216 size. This is only true if we are accessing through a pointer
1217 to a type that is the same as SFT_PARENT_VAR. Otherwise, we may
1218 be accessing through a pointer to some substruct of the
1219 structure, and if we try to prune there, we will have the wrong
1220 offset, and get the wrong answer.
1221 i.e., we can't prune without more work if we have something like
1227 const char *byte_op;
1235 foo = &targetm.asm_out.aligned_op;
1238 SFT.1, which represents hi, will have SFT_OFFSET=32 because in
1239 terms of SFT_PARENT_VAR, that is where it is.
1240 However, the access through the foo pointer will be at offset 0. */
1242 && TREE_CODE (alias) == STRUCT_FIELD_TAG
1244 && TREE_TYPE (base) == TREE_TYPE (SFT_PARENT_VAR (alias))
1245 && !overlap_subvar (offset, size, alias, NULL))
1247 #ifdef ACCESS_DEBUGGING
1248 fprintf (stderr, "Access to ");
1249 print_generic_expr (stderr, ref, 0);
1250 fprintf (stderr, " may not touch ");
1251 print_generic_expr (stderr, alias, 0);
1252 fprintf (stderr, " in function %s\n", get_name (current_function_decl));
1257 /* Without strict aliasing, it is impossible for a component access
1258 through a pointer to touch a random variable, unless that
1259 variable *is* a structure or a pointer.
1261 That is, given p->c, and some random global variable b,
1262 there is no legal way that p->c could be an access to b.
1264 Without strict aliasing on, we consider it legal to do something
1267 struct foos { int l; };
1269 static struct foos *getfoo(void);
1272 struct foos *f = getfoo();
1279 static struct foos *getfoo(void)
1280 { return (struct foos *)&foo; }
1282 (taken from 20000623-1.c)
1284 The docs also say/imply that access through union pointers
1285 is legal (but *not* if you take the address of the union member,
1286 i.e. the inverse), such that you can do
1296 U *pretmp = (U*)&rv;
1300 To implement this, we just punt on accesses through union
1303 Another case we have to allow is accessing a variable
1304 through an array access at offset zero. This happens from
1305 code generated by the fortran frontend like
1307 char[1:1] & my_char_ref;
1309 my_char_ref_1 = (char[1:1] &) &my_char;
1310 D.874_2 = (*my_char_ref_1)[1]{lb: 1 sz: 1};
1313 && flag_strict_aliasing
1314 && TREE_CODE (ref) != INDIRECT_REF
1317 && (TREE_CODE (base) != INDIRECT_REF
1318 || TREE_CODE (TREE_TYPE (base)) != UNION_TYPE)
1319 && (TREE_CODE (base) != INDIRECT_REF
1320 || TREE_CODE (ref) != ARRAY_REF
1322 || (DECL_SIZE (alias)
1323 && TREE_CODE (DECL_SIZE (alias)) == INTEGER_CST
1325 && (unsigned HOST_WIDE_INT)size
1326 != TREE_INT_CST_LOW (DECL_SIZE (alias))))
1327 && !AGGREGATE_TYPE_P (TREE_TYPE (alias))
1328 && TREE_CODE (TREE_TYPE (alias)) != COMPLEX_TYPE
1329 && !var_ann (alias)->is_heapvar
1330 /* When the struct has may_alias attached to it, we need not to
1332 && get_alias_set (base))
1334 #ifdef ACCESS_DEBUGGING
1335 fprintf (stderr, "Access to ");
1336 print_generic_expr (stderr, ref, 0);
1337 fprintf (stderr, " may not touch ");
1338 print_generic_expr (stderr, alias, 0);
1339 fprintf (stderr, " in function %s\n", get_name (current_function_decl));
1344 /* If the offset of the access is greater than the size of one of
1345 the possible aliases, it can't be touching that alias, because it
1346 would be past the end of the structure. */
1348 && flag_strict_aliasing
1349 && TREE_CODE (ref) != INDIRECT_REF
1351 && !POINTER_TYPE_P (TREE_TYPE (alias))
1353 && DECL_SIZE (alias)
1354 && TREE_CODE (DECL_SIZE (alias)) == INTEGER_CST
1355 && uoffset > TREE_INT_CST_LOW (DECL_SIZE (alias)))
1357 #ifdef ACCESS_DEBUGGING
1358 fprintf (stderr, "Access to ");
1359 print_generic_expr (stderr, ref, 0);
1360 fprintf (stderr, " may not touch ");
1361 print_generic_expr (stderr, alias, 0);
1362 fprintf (stderr, " in function %s\n", get_name (current_function_decl));
1371 /* Given an aggregate expression FULL_REF, return the number of
1372 aggregates that are containing FULL_REF. So, given a structure
1373 reference a.b.c.d, the nesting level for this expression is 2 (the
1374 number of '.' in the expression minus 1). */
1377 ref_nesting_level (tree full_ref)
1379 unsigned nesting_level = 0;
1381 if (!handled_component_p (full_ref))
1384 full_ref = TREE_OPERAND (full_ref, 0);
1385 while (handled_component_p (full_ref))
1388 full_ref = TREE_OPERAND (full_ref, 0);
1391 return nesting_level;
1395 /* Add the actual variables FULL_REF can access, given a member of
1396 FULL_REF's points-to set VAR, where FULL_REF is an access of SIZE at
1397 OFFSET from var. IS_CALL_SITE is true if this is a call, and IS_DEF
1398 is true if this is supposed to be a vdef, and false if this should
1401 The real purpose of this function is to take a points-to set for a
1402 pointer to a structure, say
1407 } foo, *foop = &foo;
1409 and discover which variables an access, such as foop->b, can alias.
1411 This is necessary because foop only actually points to foo's first
1412 member, so that is all the points-to set contains. However, an access
1413 to foop->a may be touching some single SFT if we have created some
1414 SFT's for a structure.
1416 FULL_REF is the original memory expression being analyzed. */
1419 add_vars_for_offset (tree full_ref, tree var, unsigned HOST_WIDE_INT offset,
1420 unsigned HOST_WIDE_INT size, bool is_def)
1428 && SFT_NESTING_LEVEL (var) > 0
1429 && ref_nesting_level (full_ref) < SFT_NESTING_LEVEL (var))
1431 /* Since VAR is an SFT inside a nested structure, the OFFSET
1432 computed by get_ref_base_and_extent is the offset from the
1433 start of the immediately containing structure. If VAR is an
1434 SFT inside a nested structure, then FULL_REF may be a
1435 reference to the structure immediately enclosing SFT, and so
1436 OFFSET will be the offset from the start of the immediately
1437 enclosing structure.
1439 However, to find out what other SFTs are affected by this
1440 reference, we need to know the offsets starting at the root
1441 structure in the nesting hierarchy.
1443 For instance, given the following structure:
1455 and the following address expression:
1459 This structure will receive 5 SFTs, namely 2 for fields 'a'
1460 and 'b' and 3 for the array 'c' in struct Z. So, the
1461 reference p_1->c[2] and m.e.d.c[2] access the exact same
1462 memory location (ie, SFT.5).
1464 Now, alias analysis computed the points-to set for pointer
1465 p_1 as { SFT.3 } because that is the first field that p_1
1466 actually points to. When the expression p_1->c[2] is
1467 analyzed, get_ref_base_and_extent will return an offset of 96
1468 because we are accessing the third element of the array. But
1469 the SFT we are looking for is actually at offset 160,
1470 counting from the top of struct X.
1472 Therefore, we adjust OFFSET by the offset of VAR so that we
1473 can get at all the fields starting at VAR. */
1474 offset += SFT_OFFSET (var);
1477 /* Add all subvars of var that overlap with the access.
1478 Binary search for the first relevant SFT. */
1479 sv = get_subvars_for_var (SFT_PARENT_VAR (var));
1480 if (!get_first_overlapping_subvar (sv, offset, size, &i))
1483 for (; VEC_iterate (tree, sv, i, subvar); ++i)
1485 if (SFT_OFFSET (subvar) > offset
1486 && size <= SFT_OFFSET (subvar) - offset)
1490 append_vdef (subvar);
1492 append_vuse (subvar);
1500 /* Add VAR to the virtual operands array. FLAGS is as in
1501 get_expr_operands. FULL_REF is a tree that contains the entire
1502 pointer dereference expression, if available, or NULL otherwise.
1503 OFFSET and SIZE come from the memory access expression that
1504 generated this virtual operand. IS_CALL_SITE is true if the
1505 affected statement is a call site. */
1508 add_virtual_operand (tree var, stmt_ann_t s_ann, int flags,
1509 tree full_ref, HOST_WIDE_INT offset,
1510 HOST_WIDE_INT size, bool is_call_site)
1512 bitmap aliases = NULL;
1516 sym = (TREE_CODE (var) == SSA_NAME ? SSA_NAME_VAR (var) : var);
1517 v_ann = var_ann (sym);
1519 /* Mark the statement as having memory operands. */
1520 s_ann->references_memory = true;
1522 /* If the variable cannot be modified and this is a VDEF change
1523 it into a VUSE. This happens when read-only variables are marked
1524 call-clobbered and/or aliased to writable variables. So we only
1525 check that this only happens on non-specific stores.
1527 Note that if this is a specific store, i.e. associated with a
1528 GIMPLE_MODIFY_STMT, then we can't suppress the VDEF, lest we run
1529 into validation problems.
1531 This can happen when programs cast away const, leaving us with a
1532 store to read-only memory. If the statement is actually executed
1533 at runtime, then the program is ill formed. If the statement is
1534 not executed then all is well. At the very least, we cannot ICE. */
1535 if ((flags & opf_implicit) && unmodifiable_var_p (var))
1538 /* The variable is not a GIMPLE register. Add it (or its aliases) to
1539 virtual operands, unless the caller has specifically requested
1540 not to add virtual operands (used when adding operands inside an
1541 ADDR_EXPR expression). */
1542 if (flags & opf_no_vops)
1546 aliases = MTAG_ALIASES (var);
1548 if (aliases == NULL)
1550 if (!gimple_aliases_computed_p (cfun)
1551 && (flags & opf_def))
1552 s_ann->has_volatile_ops = true;
1554 /* The variable is not aliased or it is an alias tag. */
1555 if (flags & opf_def)
1564 bool none_added = true;
1566 /* The variable is aliased. Add its aliases to the virtual
1568 gcc_assert (!bitmap_empty_p (aliases));
1570 EXECUTE_IF_SET_IN_BITMAP (aliases, 0, i, bi)
1572 tree al = referenced_var (i);
1574 /* For SFTs we have to consider all subvariables of the parent var
1575 if it is a potential points-to location. */
1576 if (TREE_CODE (al) == STRUCT_FIELD_TAG
1577 && TREE_CODE (var) == NAME_MEMORY_TAG)
1578 none_added &= !add_vars_for_offset (full_ref, al, offset, size,
1582 /* Call-clobbered tags may have non-call-clobbered
1583 symbols in their alias sets. Ignore them if we are
1584 adding VOPs for a call site. */
1585 if (is_call_site && !is_call_clobbered (al))
1588 /* If we do not know the full reference tree or if the access is
1589 unspecified [0, -1], we cannot prune it. Otherwise try doing
1590 so using access_can_touch_variable. */
1592 && !(offset == 0 && size == -1)
1593 && !access_can_touch_variable (full_ref, al, offset, size))
1596 if (flags & opf_def)
1604 if (flags & opf_def)
1606 /* If the variable is also an alias tag, add a virtual
1607 operand for it, otherwise we will miss representing
1608 references to the members of the variable's alias set.
1609 This fixes the bug in gcc.c-torture/execute/20020503-1.c.
1611 It is also necessary to add bare defs on clobbers for
1612 SMT's, so that bare SMT uses caused by pruning all the
1613 aliases will link up properly with calls. In order to
1614 keep the number of these bare defs we add down to the
1615 minimum necessary, we keep track of which SMT's were used
1616 alone in statement vdefs or VUSEs. */
1618 || (TREE_CODE (var) == SYMBOL_MEMORY_TAG
1624 /* Even if no aliases have been added, we still need to
1625 establish def-use and use-def chains, lest
1626 transformations think that this is not a memory
1627 reference. For an example of this scenario, see
1628 testsuite/g++.dg/opt/cleanup1.C. */
1636 /* Add *VAR_P to the appropriate operand array for S_ANN. FLAGS is as in
1637 get_expr_operands. If *VAR_P is a GIMPLE register, it will be added to
1638 the statement's real operands, otherwise it is added to virtual
1642 add_stmt_operand (tree *var_p, stmt_ann_t s_ann, int flags)
1647 gcc_assert (SSA_VAR_P (*var_p) && s_ann);
1650 sym = (TREE_CODE (var) == SSA_NAME ? SSA_NAME_VAR (var) : var);
1651 v_ann = var_ann (sym);
1653 /* Mark statements with volatile operands. */
1654 if (TREE_THIS_VOLATILE (sym))
1655 s_ann->has_volatile_ops = true;
1657 if (is_gimple_reg (sym))
1659 /* The variable is a GIMPLE register. Add it to real operands. */
1660 if (flags & opf_def)
1666 add_virtual_operand (var, s_ann, flags, NULL_TREE, 0, -1, false);
1669 /* Subroutine of get_indirect_ref_operands. ADDR is the address
1670 that is dereferenced, the meaning of the rest of the arguments
1671 is the same as in get_indirect_ref_operands. */
1674 get_addr_dereference_operands (tree stmt, tree *addr, int flags, tree full_ref,
1675 HOST_WIDE_INT offset, HOST_WIDE_INT size,
1676 bool recurse_on_base)
1679 stmt_ann_t s_ann = stmt_ann (stmt);
1681 s_ann->references_memory = true;
1683 if (SSA_VAR_P (ptr))
1685 struct ptr_info_def *pi = NULL;
1687 /* If PTR has flow-sensitive points-to information, use it. */
1688 if (TREE_CODE (ptr) == SSA_NAME
1689 && (pi = SSA_NAME_PTR_INFO (ptr)) != NULL
1690 && pi->name_mem_tag)
1692 /* PTR has its own memory tag. Use it. */
1693 add_virtual_operand (pi->name_mem_tag, s_ann, flags,
1694 full_ref, offset, size, false);
1698 /* If PTR is not an SSA_NAME or it doesn't have a name
1699 tag, use its symbol memory tag. */
1702 /* If we are emitting debugging dumps, display a warning if
1703 PTR is an SSA_NAME with no flow-sensitive alias
1704 information. That means that we may need to compute
1707 && TREE_CODE (ptr) == SSA_NAME
1711 "NOTE: no flow-sensitive alias info for ");
1712 print_generic_expr (dump_file, ptr, dump_flags);
1713 fprintf (dump_file, " in ");
1714 print_generic_stmt (dump_file, stmt, dump_flags);
1717 if (TREE_CODE (ptr) == SSA_NAME)
1718 ptr = SSA_NAME_VAR (ptr);
1719 v_ann = var_ann (ptr);
1721 /* If we don't know what this pointer points to then we have
1722 to make sure to not prune virtual operands based on offset
1724 if (v_ann->symbol_mem_tag)
1725 add_virtual_operand (v_ann->symbol_mem_tag, s_ann, flags,
1726 full_ref, 0, -1, false);
1728 /* Aliasing information is missing; mark statement as
1729 volatile so we won't optimize it out too actively. */
1730 else if (!gimple_aliases_computed_p (cfun)
1731 && (flags & opf_def))
1732 s_ann->has_volatile_ops = true;
1735 else if (TREE_CODE (ptr) == INTEGER_CST)
1737 /* If a constant is used as a pointer, we can't generate a real
1738 operand for it but we mark the statement volatile to prevent
1739 optimizations from messing things up. */
1740 s_ann->has_volatile_ops = true;
1745 /* Ok, this isn't even is_gimple_min_invariant. Something's broke. */
1749 /* If requested, add a USE operand for the base pointer. */
1750 if (recurse_on_base)
1751 get_expr_operands (stmt, addr, opf_use);
1755 /* A subroutine of get_expr_operands to handle INDIRECT_REF,
1756 ALIGN_INDIRECT_REF and MISALIGNED_INDIRECT_REF.
1758 STMT is the statement being processed, EXPR is the INDIRECT_REF
1761 FLAGS is as in get_expr_operands.
1763 FULL_REF contains the full pointer dereference expression, if we
1764 have it, or NULL otherwise.
1766 OFFSET and SIZE are the location of the access inside the
1767 dereferenced pointer, if known.
1769 RECURSE_ON_BASE should be set to true if we want to continue
1770 calling get_expr_operands on the base pointer, and false if
1771 something else will do it for us. */
1774 get_indirect_ref_operands (tree stmt, tree expr, int flags, tree full_ref,
1775 HOST_WIDE_INT offset, HOST_WIDE_INT size,
1776 bool recurse_on_base)
1778 tree *pptr = &TREE_OPERAND (expr, 0);
1779 stmt_ann_t s_ann = stmt_ann (stmt);
1781 if (TREE_THIS_VOLATILE (expr))
1782 s_ann->has_volatile_ops = true;
1784 get_addr_dereference_operands (stmt, pptr, flags, full_ref, offset, size,
1789 /* A subroutine of get_expr_operands to handle TARGET_MEM_REF. */
1792 get_tmr_operands (tree stmt, tree expr, int flags)
1795 stmt_ann_t s_ann = stmt_ann (stmt);
1797 /* This statement references memory. */
1798 s_ann->references_memory = 1;
1800 /* First record the real operands. */
1801 get_expr_operands (stmt, &TMR_BASE (expr), opf_use);
1802 get_expr_operands (stmt, &TMR_INDEX (expr), opf_use);
1804 if (TMR_SYMBOL (expr))
1805 add_to_addressable_set (TMR_SYMBOL (expr), &s_ann->addresses_taken);
1807 tag = TMR_TAG (expr);
1810 /* Something weird, so ensure that we will be careful. */
1811 s_ann->has_volatile_ops = true;
1816 get_expr_operands (stmt, &tag, flags);
1820 add_virtual_operand (tag, s_ann, flags, expr, 0, -1, false);
1824 /* Add clobbering definitions for .GLOBAL_VAR or for each of the call
1825 clobbered variables in the function. */
1828 add_call_clobber_ops (tree stmt, tree callee)
1832 stmt_ann_t s_ann = stmt_ann (stmt);
1833 bitmap not_read_b, not_written_b;
1835 /* If we created .GLOBAL_VAR earlier, just use it. */
1836 if (gimple_global_var (cfun))
1838 tree var = gimple_global_var (cfun);
1839 add_virtual_operand (var, s_ann, opf_def, NULL, 0, -1, true);
1843 /* Get info for local and module level statics. There is a bit
1844 set for each static if the call being processed does not read
1845 or write that variable. */
1846 not_read_b = callee ? ipa_reference_get_not_read_global (callee) : NULL;
1847 not_written_b = callee ? ipa_reference_get_not_written_global (callee) : NULL;
1849 /* Add a VDEF operand for every call clobbered variable. */
1850 EXECUTE_IF_SET_IN_BITMAP (gimple_call_clobbered_vars (cfun), 0, u, bi)
1852 tree var = referenced_var_lookup (u);
1853 unsigned int escape_mask = var_ann (var)->escape_mask;
1854 tree real_var = var;
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. */
1860 if (TREE_CODE (var) == STRUCT_FIELD_TAG)
1861 real_var = SFT_PARENT_VAR (var);
1863 not_read = not_read_b
1864 ? bitmap_bit_p (not_read_b, DECL_UID (real_var))
1867 not_written = not_written_b
1868 ? bitmap_bit_p (not_written_b, DECL_UID (real_var))
1870 gcc_assert (!unmodifiable_var_p (var));
1872 clobber_stats.clobbered_vars++;
1874 /* See if this variable is really clobbered by this function. */
1876 /* Trivial case: Things escaping only to pure/const are not
1877 clobbered by non-pure-const, and only read by pure/const. */
1878 if ((escape_mask & ~(ESCAPE_TO_PURE_CONST)) == 0)
1880 tree call = get_call_expr_in (stmt);
1881 if (call_expr_flags (call) & (ECF_CONST | ECF_PURE))
1883 add_virtual_operand (var, s_ann, opf_use, NULL, 0, -1, true);
1884 clobber_stats.unescapable_clobbers_avoided++;
1889 clobber_stats.unescapable_clobbers_avoided++;
1896 clobber_stats.static_write_clobbers_avoided++;
1898 add_virtual_operand (var, s_ann, opf_use, NULL, 0, -1, true);
1900 clobber_stats.static_read_clobbers_avoided++;
1903 add_virtual_operand (var, s_ann, opf_def, NULL, 0, -1, true);
1908 /* Add VUSE operands for .GLOBAL_VAR or all call clobbered variables in the
1912 add_call_read_ops (tree stmt, tree callee)
1916 stmt_ann_t s_ann = stmt_ann (stmt);
1919 /* if the function is not pure, it may reference memory. Add
1920 a VUSE for .GLOBAL_VAR if it has been created. See add_referenced_var
1921 for the heuristic used to decide whether to create .GLOBAL_VAR. */
1922 if (gimple_global_var (cfun))
1924 tree var = gimple_global_var (cfun);
1925 add_virtual_operand (var, s_ann, opf_use, NULL, 0, -1, true);
1929 not_read_b = callee ? ipa_reference_get_not_read_global (callee) : NULL;
1931 /* Add a VUSE for each call-clobbered variable. */
1932 EXECUTE_IF_SET_IN_BITMAP (gimple_call_clobbered_vars (cfun), 0, u, bi)
1934 tree var = referenced_var (u);
1935 tree real_var = var;
1938 clobber_stats.readonly_clobbers++;
1940 /* Not read and not written are computed on regular vars, not
1941 subvars, so look at the parent var if this is an SFT. */
1943 if (TREE_CODE (var) == STRUCT_FIELD_TAG)
1944 real_var = SFT_PARENT_VAR (var);
1946 not_read = not_read_b ? bitmap_bit_p (not_read_b, DECL_UID (real_var))
1951 clobber_stats.static_readonly_clobbers_avoided++;
1955 add_virtual_operand (var, s_ann, opf_use, NULL, 0, -1, true);
1960 /* A subroutine of get_expr_operands to handle CALL_EXPR. */
1963 get_call_expr_operands (tree stmt, tree expr)
1965 int call_flags = call_expr_flags (expr);
1967 stmt_ann_t ann = stmt_ann (stmt);
1969 ann->references_memory = true;
1971 /* If aliases have been computed already, add VDEF or VUSE
1972 operands for all the symbols that have been found to be
1974 if (gimple_aliases_computed_p (cfun)
1975 && !(call_flags & ECF_NOVOPS))
1977 /* A 'pure' or a 'const' function never call-clobbers anything.
1978 A 'noreturn' function might, but since we don't return anyway
1979 there is no point in recording that. */
1980 if (TREE_SIDE_EFFECTS (expr)
1981 && !(call_flags & (ECF_PURE | ECF_CONST | ECF_NORETURN)))
1982 add_call_clobber_ops (stmt, get_callee_fndecl (expr));
1983 else if (!(call_flags & ECF_CONST))
1984 add_call_read_ops (stmt, get_callee_fndecl (expr));
1987 /* Find uses in the called function. */
1988 get_expr_operands (stmt, &CALL_EXPR_FN (expr), opf_use);
1989 nargs = call_expr_nargs (expr);
1990 for (i = 0; i < nargs; i++)
1991 get_expr_operands (stmt, &CALL_EXPR_ARG (expr, i), opf_use);
1993 get_expr_operands (stmt, &CALL_EXPR_STATIC_CHAIN (expr), opf_use);
1997 /* Scan operands in the ASM_EXPR stmt referred to in INFO. */
2000 get_asm_expr_operands (tree stmt)
2004 const char **oconstraints;
2005 const char *constraint;
2006 bool allows_mem, allows_reg, is_inout;
2009 s_ann = stmt_ann (stmt);
2010 noutputs = list_length (ASM_OUTPUTS (stmt));
2011 oconstraints = (const char **) alloca ((noutputs) * sizeof (const char *));
2013 /* Gather all output operands. */
2014 for (i = 0, link = ASM_OUTPUTS (stmt); link; i++, link = TREE_CHAIN (link))
2016 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
2017 oconstraints[i] = constraint;
2018 parse_output_constraint (&constraint, i, 0, 0, &allows_mem,
2019 &allows_reg, &is_inout);
2021 /* This should have been split in gimplify_asm_expr. */
2022 gcc_assert (!allows_reg || !is_inout);
2024 /* Memory operands are addressable. Note that STMT needs the
2025 address of this operand. */
2026 if (!allows_reg && allows_mem)
2028 tree t = get_base_address (TREE_VALUE (link));
2029 if (t && DECL_P (t) && s_ann)
2030 add_to_addressable_set (t, &s_ann->addresses_taken);
2033 get_expr_operands (stmt, &TREE_VALUE (link), opf_def);
2036 /* Gather all input operands. */
2037 for (link = ASM_INPUTS (stmt); link; link = TREE_CHAIN (link))
2039 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
2040 parse_input_constraint (&constraint, 0, 0, noutputs, 0, oconstraints,
2041 &allows_mem, &allows_reg);
2043 /* Memory operands are addressable. Note that STMT needs the
2044 address of this operand. */
2045 if (!allows_reg && allows_mem)
2047 tree t = get_base_address (TREE_VALUE (link));
2048 if (t && DECL_P (t) && s_ann)
2049 add_to_addressable_set (t, &s_ann->addresses_taken);
2052 get_expr_operands (stmt, &TREE_VALUE (link), 0);
2055 /* Clobber all memory and addressable symbols for asm ("" : : : "memory"); */
2056 for (link = ASM_CLOBBERS (stmt); link; link = TREE_CHAIN (link))
2057 if (strcmp (TREE_STRING_POINTER (TREE_VALUE (link)), "memory") == 0)
2062 s_ann->references_memory = true;
2064 EXECUTE_IF_SET_IN_BITMAP (gimple_call_clobbered_vars (cfun), 0, i, bi)
2066 tree var = referenced_var (i);
2067 add_stmt_operand (&var, s_ann, opf_def | opf_implicit);
2070 EXECUTE_IF_SET_IN_BITMAP (gimple_addressable_vars (cfun), 0, i, bi)
2072 tree var = referenced_var (i);
2074 /* Subvars are explicitly represented in this list, so we
2075 don't need the original to be added to the clobber ops,
2076 but the original *will* be in this list because we keep
2077 the addressability of the original variable up-to-date
2078 to avoid confusing the back-end. */
2079 if (var_can_have_subvars (var)
2080 && get_subvars_for_var (var) != NULL)
2083 add_stmt_operand (&var, s_ann, opf_def | opf_implicit);
2090 /* Scan operands for the assignment expression EXPR in statement STMT. */
2093 get_modify_stmt_operands (tree stmt, tree expr)
2095 /* First get operands from the RHS. */
2096 get_expr_operands (stmt, &GIMPLE_STMT_OPERAND (expr, 1), opf_use);
2098 /* For the LHS, use a regular definition (opf_def) for GIMPLE
2099 registers. If the LHS is a store to memory, we will need
2100 a preserving definition (VDEF).
2102 Preserving definitions are those that modify a part of an
2103 aggregate object for which no subvars have been computed (or the
2104 reference does not correspond exactly to one of them). Stores
2105 through a pointer are also represented with VDEF operators.
2107 We used to distinguish between preserving and killing definitions.
2108 We always emit preserving definitions now. */
2109 get_expr_operands (stmt, &GIMPLE_STMT_OPERAND (expr, 0), opf_def);
2113 /* Recursively scan the expression pointed to by EXPR_P in statement
2114 STMT. FLAGS is one of the OPF_* constants modifying how to
2115 interpret the operands found. */
2118 get_expr_operands (tree stmt, tree *expr_p, int flags)
2120 enum tree_code code;
2121 enum tree_code_class codeclass;
2122 tree expr = *expr_p;
2123 stmt_ann_t s_ann = stmt_ann (stmt);
2128 code = TREE_CODE (expr);
2129 codeclass = TREE_CODE_CLASS (code);
2134 /* Taking the address of a variable does not represent a
2135 reference to it, but the fact that the statement takes its
2136 address will be of interest to some passes (e.g. alias
2138 add_to_addressable_set (TREE_OPERAND (expr, 0), &s_ann->addresses_taken);
2140 /* If the address is invariant, there may be no interesting
2141 variable references inside. */
2142 if (is_gimple_min_invariant (expr))
2145 /* Otherwise, there may be variables referenced inside but there
2146 should be no VUSEs created, since the referenced objects are
2147 not really accessed. The only operands that we should find
2148 here are ARRAY_REF indices which will always be real operands
2149 (GIMPLE does not allow non-registers as array indices). */
2150 flags |= opf_no_vops;
2151 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2155 case STRUCT_FIELD_TAG:
2156 case SYMBOL_MEMORY_TAG:
2157 case NAME_MEMORY_TAG:
2158 add_stmt_operand (expr_p, s_ann, flags);
2167 /* Add the subvars for a variable, if it has subvars, to DEFS
2168 or USES. Otherwise, add the variable itself. Whether it
2169 goes to USES or DEFS depends on the operand flags. */
2170 if (var_can_have_subvars (expr)
2171 && (svars = get_subvars_for_var (expr)))
2175 for (i = 0; VEC_iterate (tree, svars, i, subvar); ++i)
2176 add_stmt_operand (&subvar, s_ann, flags);
2179 add_stmt_operand (expr_p, s_ann, flags);
2184 case MISALIGNED_INDIRECT_REF:
2185 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), flags);
2188 case ALIGN_INDIRECT_REF:
2190 get_indirect_ref_operands (stmt, expr, flags, expr, 0, -1, true);
2193 case TARGET_MEM_REF:
2194 get_tmr_operands (stmt, expr, flags);
2198 case ARRAY_RANGE_REF:
2204 HOST_WIDE_INT offset, size, maxsize;
2207 if (TREE_THIS_VOLATILE (expr))
2208 s_ann->has_volatile_ops = true;
2210 /* This component reference becomes an access to all of the
2211 subvariables it can touch, if we can determine that, but
2212 *NOT* the real one. If we can't determine which fields we
2213 could touch, the recursion will eventually get to a
2214 variable and add *all* of its subvars, or whatever is the
2215 minimum correct subset. */
2216 ref = get_ref_base_and_extent (expr, &offset, &size, &maxsize);
2217 if (SSA_VAR_P (ref) && get_subvars_for_var (ref))
2219 subvar_t svars = get_subvars_for_var (ref);
2223 for (i = 0; VEC_iterate (tree, svars, i, subvar); ++i)
2227 if (overlap_subvar (offset, maxsize, subvar, &exact))
2229 int subvar_flags = flags;
2231 add_stmt_operand (&subvar, s_ann, subvar_flags);
2236 flags |= opf_no_vops;
2238 if ((DECL_P (ref) && TREE_THIS_VOLATILE (ref))
2239 || (TREE_CODE (ref) == SSA_NAME
2240 && TREE_THIS_VOLATILE (SSA_NAME_VAR (ref))))
2241 s_ann->has_volatile_ops = true;
2243 else if (TREE_CODE (ref) == INDIRECT_REF)
2245 get_indirect_ref_operands (stmt, ref, flags, expr, offset,
2247 flags |= opf_no_vops;
2250 /* Even if we found subvars above we need to ensure to see
2251 immediate uses for d in s.a[d]. In case of s.a having
2252 a subvar or we would miss it otherwise. */
2253 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2255 if (code == COMPONENT_REF)
2257 if (TREE_THIS_VOLATILE (TREE_OPERAND (expr, 1)))
2258 s_ann->has_volatile_ops = true;
2259 get_expr_operands (stmt, &TREE_OPERAND (expr, 2), opf_use);
2261 else if (code == ARRAY_REF || code == ARRAY_RANGE_REF)
2263 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), opf_use);
2264 get_expr_operands (stmt, &TREE_OPERAND (expr, 2), opf_use);
2265 get_expr_operands (stmt, &TREE_OPERAND (expr, 3), opf_use);
2271 case WITH_SIZE_EXPR:
2272 /* WITH_SIZE_EXPR is a pass-through reference to its first argument,
2273 and an rvalue reference to its second argument. */
2274 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), opf_use);
2275 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2279 get_call_expr_operands (stmt, expr);
2284 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), opf_use);
2285 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), opf_use);
2286 get_expr_operands (stmt, &TREE_OPERAND (expr, 2), opf_use);
2289 case GIMPLE_MODIFY_STMT:
2290 get_modify_stmt_operands (stmt, expr);
2295 /* General aggregate CONSTRUCTORs have been decomposed, but they
2296 are still in use as the COMPLEX_EXPR equivalent for vectors. */
2297 constructor_elt *ce;
2298 unsigned HOST_WIDE_INT idx;
2301 VEC_iterate (constructor_elt, CONSTRUCTOR_ELTS (expr), idx, ce);
2303 get_expr_operands (stmt, &ce->value, opf_use);
2309 case TRUTH_NOT_EXPR:
2310 case VIEW_CONVERT_EXPR:
2312 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2315 case TRUTH_AND_EXPR:
2317 case TRUTH_XOR_EXPR:
2323 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2324 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), flags);
2329 case REALIGN_LOAD_EXPR:
2331 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2332 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), flags);
2333 get_expr_operands (stmt, &TREE_OPERAND (expr, 2), flags);
2337 case CHANGE_DYNAMIC_TYPE_EXPR:
2338 get_expr_operands (stmt, &CHANGE_DYNAMIC_TYPE_LOCATION (expr), opf_use);
2343 tree init = OMP_FOR_INIT (expr);
2344 tree cond = OMP_FOR_COND (expr);
2345 tree incr = OMP_FOR_INCR (expr);
2346 tree c, clauses = OMP_FOR_CLAUSES (stmt);
2348 get_expr_operands (stmt, &GIMPLE_STMT_OPERAND (init, 0), opf_def);
2349 get_expr_operands (stmt, &GIMPLE_STMT_OPERAND (init, 1), opf_use);
2350 get_expr_operands (stmt, &TREE_OPERAND (cond, 1), opf_use);
2351 get_expr_operands (stmt,
2352 &TREE_OPERAND (GIMPLE_STMT_OPERAND (incr, 1), 1),
2355 c = find_omp_clause (clauses, OMP_CLAUSE_SCHEDULE);
2357 get_expr_operands (stmt, &OMP_CLAUSE_SCHEDULE_CHUNK_EXPR (c),
2364 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), opf_def);
2365 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), opf_use);
2371 tree c, clauses = OMP_PARALLEL_CLAUSES (stmt);
2373 if (OMP_PARALLEL_DATA_ARG (stmt))
2375 get_expr_operands (stmt, &OMP_PARALLEL_DATA_ARG (stmt), opf_use);
2376 add_to_addressable_set (OMP_PARALLEL_DATA_ARG (stmt),
2377 &s_ann->addresses_taken);
2380 c = find_omp_clause (clauses, OMP_CLAUSE_IF);
2382 get_expr_operands (stmt, &OMP_CLAUSE_IF_EXPR (c), opf_use);
2383 c = find_omp_clause (clauses, OMP_CLAUSE_NUM_THREADS);
2385 get_expr_operands (stmt, &OMP_CLAUSE_NUM_THREADS_EXPR (c), opf_use);
2391 get_expr_operands (stmt, &OMP_SECTIONS_CONTROL (expr), opf_def);
2395 case OMP_ATOMIC_LOAD:
2397 tree *addr = &TREE_OPERAND (expr, 1);
2398 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), opf_def);
2400 if (TREE_CODE (*addr) == ADDR_EXPR)
2401 get_expr_operands (stmt, &TREE_OPERAND (*addr, 0), opf_def);
2403 get_addr_dereference_operands (stmt, addr, opf_def,
2404 NULL_TREE, 0, -1, true);
2408 case OMP_ATOMIC_STORE:
2410 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), opf_use);
2426 case OMP_SECTIONS_SWITCH:
2427 /* Expressions that make no memory references. */
2431 if (codeclass == tcc_unary)
2433 if (codeclass == tcc_binary || codeclass == tcc_comparison)
2435 if (codeclass == tcc_constant || codeclass == tcc_type)
2439 /* If we get here, something has gone wrong. */
2440 #ifdef ENABLE_CHECKING
2441 fprintf (stderr, "unhandled expression in get_expr_operands():\n");
2443 fputs ("\n", stderr);
2449 /* Parse STMT looking for operands. When finished, the various
2450 build_* operand vectors will have potential operands in them. */
2453 parse_ssa_operands (tree stmt)
2455 enum tree_code code;
2457 code = TREE_CODE (stmt);
2460 case GIMPLE_MODIFY_STMT:
2461 get_modify_stmt_operands (stmt, stmt);
2465 get_expr_operands (stmt, &COND_EXPR_COND (stmt), opf_use);
2469 get_expr_operands (stmt, &SWITCH_COND (stmt), opf_use);
2473 get_asm_expr_operands (stmt);
2477 get_expr_operands (stmt, &TREE_OPERAND (stmt, 0), opf_use);
2481 get_expr_operands (stmt, &GOTO_DESTINATION (stmt), opf_use);
2485 get_expr_operands (stmt, &LABEL_EXPR_LABEL (stmt), opf_use);
2489 case CASE_LABEL_EXPR:
2490 case TRY_CATCH_EXPR:
2491 case TRY_FINALLY_EXPR:
2492 case EH_FILTER_EXPR:
2495 /* These nodes contain no variable references. */
2499 /* Notice that if get_expr_operands tries to use &STMT as the
2500 operand pointer (which may only happen for USE operands), we
2501 will fail in add_stmt_operand. This default will handle
2502 statements like empty statements, or CALL_EXPRs that may
2503 appear on the RHS of a statement or as statements themselves. */
2504 get_expr_operands (stmt, &stmt, opf_use);
2510 /* Create an operands cache for STMT. */
2513 build_ssa_operands (tree stmt)
2515 stmt_ann_t ann = get_stmt_ann (stmt);
2517 /* Initially assume that the statement has no volatile operands and
2518 makes no memory references. */
2519 ann->has_volatile_ops = false;
2520 ann->references_memory = false;
2521 /* Just clear the bitmap so we don't end up reallocating it over and over. */
2522 if (ann->addresses_taken)
2523 bitmap_clear (ann->addresses_taken);
2525 start_ssa_stmt_operands ();
2526 parse_ssa_operands (stmt);
2527 operand_build_sort_virtual (build_vuses);
2528 operand_build_sort_virtual (build_vdefs);
2529 finalize_ssa_stmt_operands (stmt);
2531 if (ann->addresses_taken && bitmap_empty_p (ann->addresses_taken))
2532 ann->addresses_taken = NULL;
2534 /* For added safety, assume that statements with volatile operands
2535 also reference memory. */
2536 if (ann->has_volatile_ops)
2537 ann->references_memory = true;
2541 /* Releases the operands of STMT back to their freelists, and clears
2542 the stmt operand lists. */
2545 free_stmt_operands (tree stmt)
2547 def_optype_p defs = DEF_OPS (stmt), last_def;
2548 use_optype_p uses = USE_OPS (stmt), last_use;
2549 voptype_p vuses = VUSE_OPS (stmt);
2550 voptype_p vdefs = VDEF_OPS (stmt), vdef, next_vdef;
2555 for (last_def = defs; last_def->next; last_def = last_def->next)
2557 last_def->next = gimple_ssa_operands (cfun)->free_defs;
2558 gimple_ssa_operands (cfun)->free_defs = defs;
2559 DEF_OPS (stmt) = NULL;
2564 for (last_use = uses; last_use->next; last_use = last_use->next)
2565 delink_imm_use (USE_OP_PTR (last_use));
2566 delink_imm_use (USE_OP_PTR (last_use));
2567 last_use->next = gimple_ssa_operands (cfun)->free_uses;
2568 gimple_ssa_operands (cfun)->free_uses = uses;
2569 USE_OPS (stmt) = NULL;
2574 for (i = 0; i < VUSE_NUM (vuses); i++)
2575 delink_imm_use (VUSE_OP_PTR (vuses, i));
2576 add_vop_to_freelist (vuses);
2577 VUSE_OPS (stmt) = NULL;
2582 for (vdef = vdefs; vdef; vdef = next_vdef)
2584 next_vdef = vdef->next;
2585 delink_imm_use (VDEF_OP_PTR (vdef, 0));
2586 add_vop_to_freelist (vdef);
2588 VDEF_OPS (stmt) = NULL;
2593 /* Free any operands vectors in OPS. */
2596 free_ssa_operands (stmt_operands_p ops)
2598 ops->def_ops = NULL;
2599 ops->use_ops = NULL;
2600 ops->vdef_ops = NULL;
2601 ops->vuse_ops = NULL;
2602 BITMAP_FREE (ops->loads);
2603 BITMAP_FREE (ops->stores);
2607 /* Get the operands of statement STMT. */
2610 update_stmt_operands (tree stmt)
2612 stmt_ann_t ann = get_stmt_ann (stmt);
2614 /* If update_stmt_operands is called before SSA is initialized, do
2616 if (!ssa_operands_active ())
2619 /* The optimizers cannot handle statements that are nothing but a
2620 _DECL. This indicates a bug in the gimplifier. */
2621 gcc_assert (!SSA_VAR_P (stmt));
2623 timevar_push (TV_TREE_OPS);
2625 gcc_assert (ann->modified);
2626 build_ssa_operands (stmt);
2629 timevar_pop (TV_TREE_OPS);
2633 /* Copies virtual operands from SRC to DST. */
2636 copy_virtual_operands (tree dest, tree src)
2639 voptype_p src_vuses, dest_vuses;
2640 voptype_p src_vdefs, dest_vdefs;
2641 struct voptype_d vuse;
2642 struct voptype_d vdef;
2643 stmt_ann_t dest_ann;
2645 VDEF_OPS (dest) = NULL;
2646 VUSE_OPS (dest) = NULL;
2648 dest_ann = get_stmt_ann (dest);
2649 BITMAP_FREE (dest_ann->operands.loads);
2650 BITMAP_FREE (dest_ann->operands.stores);
2652 if (LOADED_SYMS (src))
2654 dest_ann->operands.loads = BITMAP_ALLOC (&operands_bitmap_obstack);
2655 bitmap_copy (dest_ann->operands.loads, LOADED_SYMS (src));
2658 if (STORED_SYMS (src))
2660 dest_ann->operands.stores = BITMAP_ALLOC (&operands_bitmap_obstack);
2661 bitmap_copy (dest_ann->operands.stores, STORED_SYMS (src));
2664 /* Copy all the VUSE operators and corresponding operands. */
2666 for (src_vuses = VUSE_OPS (src); src_vuses; src_vuses = src_vuses->next)
2668 n = VUSE_NUM (src_vuses);
2669 dest_vuses = add_vuse_op (dest, NULL_TREE, n, dest_vuses);
2670 for (i = 0; i < n; i++)
2671 SET_USE (VUSE_OP_PTR (dest_vuses, i), VUSE_OP (src_vuses, i));
2673 if (VUSE_OPS (dest) == NULL)
2674 VUSE_OPS (dest) = vuse.next;
2677 /* Copy all the VDEF operators and corresponding operands. */
2679 for (src_vdefs = VDEF_OPS (src); src_vdefs; src_vdefs = src_vdefs->next)
2681 n = VUSE_NUM (src_vdefs);
2682 dest_vdefs = add_vdef_op (dest, NULL_TREE, n, dest_vdefs);
2683 VDEF_RESULT (dest_vdefs) = VDEF_RESULT (src_vdefs);
2684 for (i = 0; i < n; i++)
2685 SET_USE (VUSE_OP_PTR (dest_vdefs, i), VUSE_OP (src_vdefs, i));
2687 if (VDEF_OPS (dest) == NULL)
2688 VDEF_OPS (dest) = vdef.next;
2693 /* Specifically for use in DOM's expression analysis. Given a store, we
2694 create an artificial stmt which looks like a load from the store, this can
2695 be used to eliminate redundant loads. OLD_OPS are the operands from the
2696 store stmt, and NEW_STMT is the new load which represents a load of the
2700 create_ssa_artificial_load_stmt (tree new_stmt, tree old_stmt)
2704 use_operand_p use_p;
2707 get_stmt_ann (new_stmt);
2709 /* Process NEW_STMT looking for operands. */
2710 start_ssa_stmt_operands ();
2711 parse_ssa_operands (new_stmt);
2713 for (i = 0; VEC_iterate (tree, build_vuses, i, op); i++)
2714 if (TREE_CODE (op) != SSA_NAME)
2715 var_ann (op)->in_vuse_list = false;
2717 for (i = 0; VEC_iterate (tree, build_vuses, i, op); i++)
2718 if (TREE_CODE (op) != SSA_NAME)
2719 var_ann (op)->in_vdef_list = false;
2721 /* Remove any virtual operands that were found. */
2722 VEC_truncate (tree, build_vdefs, 0);
2723 VEC_truncate (tree, build_vuses, 0);
2725 /* For each VDEF on the original statement, we want to create a
2726 VUSE of the VDEF result operand on the new statement. */
2727 FOR_EACH_SSA_TREE_OPERAND (op, old_stmt, iter, SSA_OP_VDEF)
2730 finalize_ssa_stmt_operands (new_stmt);
2732 /* All uses in this fake stmt must not be in the immediate use lists. */
2733 FOR_EACH_SSA_USE_OPERAND (use_p, new_stmt, iter, SSA_OP_ALL_USES)
2734 delink_imm_use (use_p);
2738 /* Swap operands EXP0 and EXP1 in statement STMT. No attempt is done
2739 to test the validity of the swap operation. */
2742 swap_tree_operands (tree stmt, tree *exp0, tree *exp1)
2748 /* If the operand cache is active, attempt to preserve the relative
2749 positions of these two operands in their respective immediate use
2751 if (ssa_operands_active () && op0 != op1)
2753 use_optype_p use0, use1, ptr;
2756 /* Find the 2 operands in the cache, if they are there. */
2757 for (ptr = USE_OPS (stmt); ptr; ptr = ptr->next)
2758 if (USE_OP_PTR (ptr)->use == exp0)
2764 for (ptr = USE_OPS (stmt); ptr; ptr = ptr->next)
2765 if (USE_OP_PTR (ptr)->use == exp1)
2771 /* If both uses don't have operand entries, there isn't much we can do
2772 at this point. Presumably we don't need to worry about it. */
2775 tree *tmp = USE_OP_PTR (use1)->use;
2776 USE_OP_PTR (use1)->use = USE_OP_PTR (use0)->use;
2777 USE_OP_PTR (use0)->use = tmp;
2781 /* Now swap the data. */
2787 /* Add the base address of REF to the set *ADDRESSES_TAKEN. If
2788 *ADDRESSES_TAKEN is NULL, a new set is created. REF may be
2789 a single variable whose address has been taken or any other valid
2790 GIMPLE memory reference (structure reference, array, etc). If the
2791 base address of REF is a decl that has sub-variables, also add all
2792 of its sub-variables. */
2795 add_to_addressable_set (tree ref, bitmap *addresses_taken)
2800 gcc_assert (addresses_taken);
2802 /* Note that it is *NOT OKAY* to use the target of a COMPONENT_REF
2803 as the only thing we take the address of. If VAR is a structure,
2804 taking the address of a field means that the whole structure may
2805 be referenced using pointer arithmetic. See PR 21407 and the
2806 ensuing mailing list discussion. */
2807 var = get_base_address (ref);
2808 if (var && SSA_VAR_P (var))
2810 if (*addresses_taken == NULL)
2811 *addresses_taken = BITMAP_GGC_ALLOC ();
2813 if (var_can_have_subvars (var)
2814 && (svars = get_subvars_for_var (var)))
2818 for (i = 0; VEC_iterate (tree, svars, i, subvar); ++i)
2820 bitmap_set_bit (*addresses_taken, DECL_UID (subvar));
2821 TREE_ADDRESSABLE (subvar) = 1;
2826 bitmap_set_bit (*addresses_taken, DECL_UID (var));
2827 TREE_ADDRESSABLE (var) = 1;
2833 /* Scan the immediate_use list for VAR making sure its linked properly.
2834 Return TRUE if there is a problem and emit an error message to F. */
2837 verify_imm_links (FILE *f, tree var)
2839 use_operand_p ptr, prev, list;
2842 gcc_assert (TREE_CODE (var) == SSA_NAME);
2844 list = &(SSA_NAME_IMM_USE_NODE (var));
2845 gcc_assert (list->use == NULL);
2847 if (list->prev == NULL)
2849 gcc_assert (list->next == NULL);
2855 for (ptr = list->next; ptr != list; )
2857 if (prev != ptr->prev)
2860 if (ptr->use == NULL)
2861 goto error; /* 2 roots, or SAFE guard node. */
2862 else if (*(ptr->use) != var)
2868 /* Avoid infinite loops. 50,000,000 uses probably indicates a
2870 if (count++ > 50000000)
2874 /* Verify list in the other direction. */
2876 for (ptr = list->prev; ptr != list; )
2878 if (prev != ptr->next)
2892 if (ptr->stmt && stmt_modified_p (ptr->stmt))
2894 fprintf (f, " STMT MODIFIED. - <%p> ", (void *)ptr->stmt);
2895 print_generic_stmt (f, ptr->stmt, TDF_SLIM);
2897 fprintf (f, " IMM ERROR : (use_p : tree - %p:%p)", (void *)ptr,
2899 print_generic_expr (f, USE_FROM_PTR (ptr), TDF_SLIM);
2905 /* Dump all the immediate uses to FILE. */
2908 dump_immediate_uses_for (FILE *file, tree var)
2910 imm_use_iterator iter;
2911 use_operand_p use_p;
2913 gcc_assert (var && TREE_CODE (var) == SSA_NAME);
2915 print_generic_expr (file, var, TDF_SLIM);
2916 fprintf (file, " : -->");
2917 if (has_zero_uses (var))
2918 fprintf (file, " no uses.\n");
2920 if (has_single_use (var))
2921 fprintf (file, " single use.\n");
2923 fprintf (file, "%d uses.\n", num_imm_uses (var));
2925 FOR_EACH_IMM_USE_FAST (use_p, iter, var)
2927 if (use_p->stmt == NULL && use_p->use == NULL)
2928 fprintf (file, "***end of stmt iterator marker***\n");
2930 if (!is_gimple_reg (USE_FROM_PTR (use_p)))
2931 print_generic_stmt (file, USE_STMT (use_p), TDF_VOPS|TDF_MEMSYMS);
2933 print_generic_stmt (file, USE_STMT (use_p), TDF_SLIM);
2935 fprintf(file, "\n");
2939 /* Dump all the immediate uses to FILE. */
2942 dump_immediate_uses (FILE *file)
2947 fprintf (file, "Immediate_uses: \n\n");
2948 for (x = 1; x < num_ssa_names; x++)
2953 dump_immediate_uses_for (file, var);
2958 /* Dump def-use edges on stderr. */
2961 debug_immediate_uses (void)
2963 dump_immediate_uses (stderr);
2967 /* Dump def-use edges on stderr. */
2970 debug_immediate_uses_for (tree var)
2972 dump_immediate_uses_for (stderr, var);
2976 /* Create a new change buffer for the statement pointed by STMT_P and
2977 push the buffer into SCB_STACK. Each change buffer
2978 records state information needed to determine what changed in the
2979 statement. Mainly, this keeps track of symbols that may need to be
2980 put into SSA form, SSA name replacements and other information
2981 needed to keep the SSA form up to date. */
2984 push_stmt_changes (tree *stmt_p)
2991 /* It makes no sense to keep track of PHI nodes. */
2992 if (TREE_CODE (stmt) == PHI_NODE)
2995 buf = XNEW (struct scb_d);
2996 memset (buf, 0, sizeof *buf);
2998 buf->stmt_p = stmt_p;
3000 if (stmt_references_memory_p (stmt))
3005 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_VUSE)
3007 tree sym = TREE_CODE (op) == SSA_NAME ? SSA_NAME_VAR (op) : op;
3008 if (buf->loads == NULL)
3009 buf->loads = BITMAP_ALLOC (NULL);
3010 bitmap_set_bit (buf->loads, DECL_UID (sym));
3013 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_VDEF)
3015 tree sym = TREE_CODE (op) == SSA_NAME ? SSA_NAME_VAR (op) : op;
3016 if (buf->stores == NULL)
3017 buf->stores = BITMAP_ALLOC (NULL);
3018 bitmap_set_bit (buf->stores, DECL_UID (sym));
3022 VEC_safe_push (scb_t, heap, scb_stack, buf);
3026 /* Given two sets S1 and S2, mark the symbols that differ in S1 and S2
3027 for renaming. The set to mark for renaming is (S1 & ~S2) | (S2 & ~S1). */
3030 mark_difference_for_renaming (bitmap s1, bitmap s2)
3032 if (s1 == NULL && s2 == NULL)
3035 if (s1 && s2 == NULL)
3036 mark_set_for_renaming (s1);
3037 else if (s1 == NULL && s2)
3038 mark_set_for_renaming (s2);
3039 else if (!bitmap_equal_p (s1, s2))
3041 bitmap t1 = BITMAP_ALLOC (NULL);
3042 bitmap t2 = BITMAP_ALLOC (NULL);
3044 bitmap_and_compl (t1, s1, s2);
3045 bitmap_and_compl (t2, s2, s1);
3046 bitmap_ior_into (t1, t2);
3047 mark_set_for_renaming (t1);
3055 /* Pop the top SCB from SCB_STACK and act on the differences between
3056 what was recorded by push_stmt_changes and the current state of
3060 pop_stmt_changes (tree *stmt_p)
3064 bitmap loads, stores;
3069 /* It makes no sense to keep track of PHI nodes. */
3070 if (TREE_CODE (stmt) == PHI_NODE)
3073 buf = VEC_pop (scb_t, scb_stack);
3074 gcc_assert (stmt_p == buf->stmt_p);
3076 /* Force an operand re-scan on the statement and mark any newly
3077 exposed variables. */
3080 /* Determine whether any memory symbols need to be renamed. If the
3081 sets of loads and stores are different after the statement is
3082 modified, then the affected symbols need to be renamed.
3084 Note that it may be possible for the statement to not reference
3085 memory anymore, but we still need to act on the differences in
3086 the sets of symbols. */
3087 loads = stores = NULL;
3088 if (stmt_references_memory_p (stmt))
3093 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_VUSE)
3095 tree sym = TREE_CODE (op) == SSA_NAME ? SSA_NAME_VAR (op) : op;
3097 loads = BITMAP_ALLOC (NULL);
3098 bitmap_set_bit (loads, DECL_UID (sym));
3101 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_VDEF)
3103 tree sym = TREE_CODE (op) == SSA_NAME ? SSA_NAME_VAR (op) : op;
3105 stores = BITMAP_ALLOC (NULL);
3106 bitmap_set_bit (stores, DECL_UID (sym));
3110 /* If LOADS is different from BUF->LOADS, the affected
3111 symbols need to be marked for renaming. */
3112 mark_difference_for_renaming (loads, buf->loads);
3114 /* Similarly for STORES and BUF->STORES. */
3115 mark_difference_for_renaming (stores, buf->stores);
3117 /* Mark all the naked GIMPLE register operands for renaming. */
3118 FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_DEF|SSA_OP_USE)
3120 mark_sym_for_renaming (op);
3122 /* FIXME, need to add more finalizers here. Cleanup EH info,
3123 recompute invariants for address expressions, add
3124 SSA replacement mappings, etc. For instance, given
3125 testsuite/gcc.c-torture/compile/pr16808.c, we fold a statement of
3128 # SMT.4_20 = VDEF <SMT.4_16>
3131 So, the VDEF will disappear, but instead of marking SMT.4 for
3132 renaming it would be far more efficient to establish a
3133 replacement mapping that would replace every reference of
3134 SMT.4_20 with SMT.4_16. */
3136 /* Free memory used by the buffer. */
3137 BITMAP_FREE (buf->loads);
3138 BITMAP_FREE (buf->stores);
3139 BITMAP_FREE (loads);
3140 BITMAP_FREE (stores);
3146 /* Discard the topmost change buffer from SCB_STACK. This is useful
3147 when the caller realized that it did not actually modified the
3148 statement. It avoids the expensive operand re-scan. */
3151 discard_stmt_changes (tree *stmt_p)
3156 /* It makes no sense to keep track of PHI nodes. */
3158 if (TREE_CODE (stmt) == PHI_NODE)
3161 buf = VEC_pop (scb_t, scb_stack);
3162 gcc_assert (stmt_p == buf->stmt_p);
3164 /* Free memory used by the buffer. */
3165 BITMAP_FREE (buf->loads);
3166 BITMAP_FREE (buf->stores);
3172 /* Returns true if statement STMT may access memory. */
3175 stmt_references_memory_p (tree stmt)
3177 if (!gimple_ssa_operands (cfun)->ops_active || TREE_CODE (stmt) == PHI_NODE)
3180 return stmt_ann (stmt)->references_memory;