1 /* Alias analysis for trees.
2 Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010
3 Free Software Foundation, Inc.
4 Contributed by Diego Novillo <dnovillo@redhat.com>
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
24 #include "coretypes.h"
29 #include "hard-reg-set.h"
30 #include "basic-block.h"
34 #include "langhooks.h"
37 #include "diagnostic.h"
38 #include "tree-dump.h"
40 #include "tree-flow.h"
41 #include "tree-inline.h"
42 #include "tree-pass.h"
45 #include "ipa-type-escape.h"
49 #include "pointer-set.h"
50 #include "alloc-pool.h"
51 #include "tree-ssa-alias.h"
53 /* Broad overview of how alias analysis on gimple works:
55 Statements clobbering or using memory are linked through the
56 virtual operand factored use-def chain. The virtual operand
57 is unique per function, its symbol is accessible via gimple_vop (cfun).
58 Virtual operands are used for efficiently walking memory statements
59 in the gimple IL and are useful for things like value-numbering as
60 a generation count for memory references.
62 SSA_NAME pointers may have associated points-to information
63 accessible via the SSA_NAME_PTR_INFO macro. Flow-insensitive
64 points-to information is (re-)computed by the TODO_rebuild_alias
65 pass manager todo. Points-to information is also used for more
66 precise tracking of call-clobbered and call-used variables and
67 related disambiguations.
69 This file contains functions for disambiguating memory references,
70 the so called alias-oracle and tools for walking of the gimple IL.
72 The main alias-oracle entry-points are
74 bool stmt_may_clobber_ref_p (gimple, tree)
76 This function queries if a statement may invalidate (parts of)
77 the memory designated by the reference tree argument.
79 bool ref_maybe_used_by_stmt_p (gimple, tree)
81 This function queries if a statement may need (parts of) the
82 memory designated by the reference tree argument.
84 There are variants of these functions that only handle the call
85 part of a statement, call_may_clobber_ref_p and ref_maybe_used_by_call_p.
86 Note that these do not disambiguate against a possible call lhs.
88 bool refs_may_alias_p (tree, tree)
90 This function tries to disambiguate two reference trees.
92 bool ptr_deref_may_alias_global_p (tree)
94 This function queries if dereferencing a pointer variable may
97 More low-level disambiguators are available and documented in
98 this file. Low-level disambiguators dealing with points-to
99 information are in tree-ssa-structalias.c. */
102 /* Query statistics for the different low-level disambiguators.
103 A high-level query may trigger multiple of them. */
106 unsigned HOST_WIDE_INT refs_may_alias_p_may_alias;
107 unsigned HOST_WIDE_INT refs_may_alias_p_no_alias;
108 unsigned HOST_WIDE_INT ref_maybe_used_by_call_p_may_alias;
109 unsigned HOST_WIDE_INT ref_maybe_used_by_call_p_no_alias;
110 unsigned HOST_WIDE_INT call_may_clobber_ref_p_may_alias;
111 unsigned HOST_WIDE_INT call_may_clobber_ref_p_no_alias;
115 dump_alias_stats (FILE *s)
117 fprintf (s, "\nAlias oracle query stats:\n");
118 fprintf (s, " refs_may_alias_p: "
119 HOST_WIDE_INT_PRINT_DEC" disambiguations, "
120 HOST_WIDE_INT_PRINT_DEC" queries\n",
121 alias_stats.refs_may_alias_p_no_alias,
122 alias_stats.refs_may_alias_p_no_alias
123 + alias_stats.refs_may_alias_p_may_alias);
124 fprintf (s, " ref_maybe_used_by_call_p: "
125 HOST_WIDE_INT_PRINT_DEC" disambiguations, "
126 HOST_WIDE_INT_PRINT_DEC" queries\n",
127 alias_stats.ref_maybe_used_by_call_p_no_alias,
128 alias_stats.refs_may_alias_p_no_alias
129 + alias_stats.ref_maybe_used_by_call_p_may_alias);
130 fprintf (s, " call_may_clobber_ref_p: "
131 HOST_WIDE_INT_PRINT_DEC" disambiguations, "
132 HOST_WIDE_INT_PRINT_DEC" queries\n",
133 alias_stats.call_may_clobber_ref_p_no_alias,
134 alias_stats.call_may_clobber_ref_p_no_alias
135 + alias_stats.call_may_clobber_ref_p_may_alias);
139 /* Return true, if dereferencing PTR may alias with a global variable. */
142 ptr_deref_may_alias_global_p (tree ptr)
144 struct ptr_info_def *pi;
146 /* If we end up with a pointer constant here that may point
148 if (TREE_CODE (ptr) != SSA_NAME)
151 pi = SSA_NAME_PTR_INFO (ptr);
153 /* If we do not have points-to information for this variable,
158 /* ??? This does not use TBAA to prune globals ptr may not access. */
159 return pt_solution_includes_global (&pi->pt);
162 /* Return true if dereferencing PTR may alias DECL.
163 The caller is responsible for applying TBAA to see if PTR
164 may access DECL at all. */
167 ptr_deref_may_alias_decl_p (tree ptr, tree decl)
169 struct ptr_info_def *pi;
171 gcc_assert ((TREE_CODE (ptr) == SSA_NAME
172 || TREE_CODE (ptr) == ADDR_EXPR
173 || TREE_CODE (ptr) == INTEGER_CST)
174 && (TREE_CODE (decl) == VAR_DECL
175 || TREE_CODE (decl) == PARM_DECL
176 || TREE_CODE (decl) == RESULT_DECL));
178 /* Non-aliased variables can not be pointed to. */
179 if (!may_be_aliased (decl))
182 /* ADDR_EXPR pointers either just offset another pointer or directly
183 specify the pointed-to set. */
184 if (TREE_CODE (ptr) == ADDR_EXPR)
186 tree base = get_base_address (TREE_OPERAND (ptr, 0));
188 && INDIRECT_REF_P (base))
189 ptr = TREE_OPERAND (base, 0);
194 && CONSTANT_CLASS_P (base))
200 /* We can end up with dereferencing constant pointers.
201 Just bail out in this case. */
202 if (TREE_CODE (ptr) == INTEGER_CST)
205 /* If we do not have useful points-to information for this pointer
206 we cannot disambiguate anything else. */
207 pi = SSA_NAME_PTR_INFO (ptr);
211 /* If the decl can be used as a restrict tag and we have a restrict
212 pointer and that pointers points-to set doesn't contain this decl
213 then they can't alias. */
214 if (DECL_RESTRICTED_P (decl)
215 && TYPE_RESTRICT (TREE_TYPE (ptr))
216 && pi->pt.vars_contains_restrict)
217 return bitmap_bit_p (pi->pt.vars, DECL_UID (decl));
219 return pt_solution_includes (&pi->pt, decl);
222 /* Return true if dereferenced PTR1 and PTR2 may alias.
223 The caller is responsible for applying TBAA to see if accesses
224 through PTR1 and PTR2 may conflict at all. */
227 ptr_derefs_may_alias_p (tree ptr1, tree ptr2)
229 struct ptr_info_def *pi1, *pi2;
231 gcc_assert ((TREE_CODE (ptr1) == SSA_NAME
232 || TREE_CODE (ptr1) == ADDR_EXPR
233 || TREE_CODE (ptr1) == INTEGER_CST)
234 && (TREE_CODE (ptr2) == SSA_NAME
235 || TREE_CODE (ptr2) == ADDR_EXPR
236 || TREE_CODE (ptr2) == INTEGER_CST));
238 /* ADDR_EXPR pointers either just offset another pointer or directly
239 specify the pointed-to set. */
240 if (TREE_CODE (ptr1) == ADDR_EXPR)
242 tree base = get_base_address (TREE_OPERAND (ptr1, 0));
244 && INDIRECT_REF_P (base))
245 ptr1 = TREE_OPERAND (base, 0);
248 return ptr_deref_may_alias_decl_p (ptr2, base);
252 if (TREE_CODE (ptr2) == ADDR_EXPR)
254 tree base = get_base_address (TREE_OPERAND (ptr2, 0));
256 && INDIRECT_REF_P (base))
257 ptr2 = TREE_OPERAND (base, 0);
260 return ptr_deref_may_alias_decl_p (ptr1, base);
265 /* We can end up with dereferencing constant pointers.
266 Just bail out in this case. */
267 if (TREE_CODE (ptr1) == INTEGER_CST
268 || TREE_CODE (ptr2) == INTEGER_CST)
271 /* We may end up with two empty points-to solutions for two same pointers.
272 In this case we still want to say both pointers alias, so shortcut
277 /* If we do not have useful points-to information for either pointer
278 we cannot disambiguate anything else. */
279 pi1 = SSA_NAME_PTR_INFO (ptr1);
280 pi2 = SSA_NAME_PTR_INFO (ptr2);
284 /* If both pointers are restrict-qualified try to disambiguate
285 with restrict information. */
286 if (TYPE_RESTRICT (TREE_TYPE (ptr1))
287 && TYPE_RESTRICT (TREE_TYPE (ptr2))
288 && !pt_solutions_same_restrict_base (&pi1->pt, &pi2->pt))
291 /* ??? This does not use TBAA to prune decls from the intersection
292 that not both pointers may access. */
293 return pt_solutions_intersect (&pi1->pt, &pi2->pt);
296 /* Return true if dereferencing PTR may alias *REF.
297 The caller is responsible for applying TBAA to see if PTR
298 may access *REF at all. */
301 ptr_deref_may_alias_ref_p_1 (tree ptr, ao_ref *ref)
303 tree base = ao_ref_base (ref);
305 if (INDIRECT_REF_P (base))
306 return ptr_derefs_may_alias_p (ptr, TREE_OPERAND (base, 0));
307 else if (SSA_VAR_P (base))
308 return ptr_deref_may_alias_decl_p (ptr, base);
314 /* Dump alias information on FILE. */
317 dump_alias_info (FILE *file)
321 = lang_hooks.decl_printable_name (current_function_decl, 2);
322 referenced_var_iterator rvi;
325 fprintf (file, "\n\nAlias information for %s\n\n", funcname);
327 fprintf (file, "Aliased symbols\n\n");
329 FOR_EACH_REFERENCED_VAR (var, rvi)
331 if (may_be_aliased (var))
332 dump_variable (file, var);
335 fprintf (file, "\nCall clobber information\n");
337 fprintf (file, "\nESCAPED");
338 dump_points_to_solution (file, &cfun->gimple_df->escaped);
339 fprintf (file, "\nCALLUSED");
340 dump_points_to_solution (file, &cfun->gimple_df->callused);
342 fprintf (file, "\n\nFlow-insensitive points-to information\n\n");
344 for (i = 1; i < num_ssa_names; i++)
346 tree ptr = ssa_name (i);
347 struct ptr_info_def *pi;
350 || SSA_NAME_IN_FREE_LIST (ptr))
353 pi = SSA_NAME_PTR_INFO (ptr);
355 dump_points_to_info_for (file, ptr);
358 fprintf (file, "\n");
362 /* Dump alias information on stderr. */
365 debug_alias_info (void)
367 dump_alias_info (stderr);
371 /* Return the alias information associated with pointer T. It creates a
372 new instance if none existed. */
374 struct ptr_info_def *
375 get_ptr_info (tree t)
377 struct ptr_info_def *pi;
379 gcc_assert (POINTER_TYPE_P (TREE_TYPE (t)));
381 pi = SSA_NAME_PTR_INFO (t);
384 pi = GGC_CNEW (struct ptr_info_def);
385 pt_solution_reset (&pi->pt);
386 SSA_NAME_PTR_INFO (t) = pi;
392 /* Dump the points-to set *PT into FILE. */
395 dump_points_to_solution (FILE *file, struct pt_solution *pt)
398 fprintf (file, ", points-to anything");
401 fprintf (file, ", points-to non-local");
404 fprintf (file, ", points-to escaped");
407 fprintf (file, ", points-to NULL");
411 fprintf (file, ", points-to vars: ");
412 dump_decl_set (file, pt->vars);
413 if (pt->vars_contains_global)
414 fprintf (file, " (includes global vars)");
418 /* Dump points-to information for SSA_NAME PTR into FILE. */
421 dump_points_to_info_for (FILE *file, tree ptr)
423 struct ptr_info_def *pi = SSA_NAME_PTR_INFO (ptr);
425 print_generic_expr (file, ptr, dump_flags);
428 dump_points_to_solution (file, &pi->pt);
430 fprintf (file, ", points-to anything");
432 fprintf (file, "\n");
436 /* Dump points-to information for VAR into stderr. */
439 debug_points_to_info_for (tree var)
441 dump_points_to_info_for (stderr, var);
445 /* Initializes the alias-oracle reference representation *R from REF. */
448 ao_ref_init (ao_ref *r, tree ref)
455 r->ref_alias_set = -1;
456 r->base_alias_set = -1;
459 /* Returns the base object of the memory reference *REF. */
462 ao_ref_base (ao_ref *ref)
466 ref->base = get_ref_base_and_extent (ref->ref, &ref->offset, &ref->size,
471 /* Returns the base object alias set of the memory reference *REF. */
473 static alias_set_type ATTRIBUTE_UNUSED
474 ao_ref_base_alias_set (ao_ref *ref)
476 if (ref->base_alias_set != -1)
477 return ref->base_alias_set;
478 ref->base_alias_set = get_alias_set (ao_ref_base (ref));
479 return ref->base_alias_set;
482 /* Returns the reference alias set of the memory reference *REF. */
485 ao_ref_alias_set (ao_ref *ref)
487 if (ref->ref_alias_set != -1)
488 return ref->ref_alias_set;
489 ref->ref_alias_set = get_alias_set (ref->ref);
490 return ref->ref_alias_set;
493 /* Init an alias-oracle reference representation from a gimple pointer
494 PTR and a gimple size SIZE in bytes. If SIZE is NULL_TREE the the
495 size is assumed to be unknown. The access is assumed to be only
496 to or after of the pointer target, not before it. */
499 ao_ref_init_from_ptr_and_size (ao_ref *ref, tree ptr, tree size)
501 HOST_WIDE_INT t1, t2;
502 ref->ref = NULL_TREE;
503 if (TREE_CODE (ptr) == ADDR_EXPR)
504 ref->base = get_ref_base_and_extent (TREE_OPERAND (ptr, 0),
505 &ref->offset, &t1, &t2);
508 ref->base = build1 (INDIRECT_REF, char_type_node, ptr);
512 && host_integerp (size, 0)
513 && TREE_INT_CST_LOW (size) * 8 / 8 == TREE_INT_CST_LOW (size))
514 ref->max_size = ref->size = TREE_INT_CST_LOW (size) * 8;
516 ref->max_size = ref->size = -1;
517 ref->ref_alias_set = 0;
518 ref->base_alias_set = 0;
521 /* Return 1 if TYPE1 and TYPE2 are to be considered equivalent for the
522 purpose of TBAA. Return 0 if they are distinct and -1 if we cannot
526 same_type_for_tbaa (tree type1, tree type2)
528 type1 = TYPE_MAIN_VARIANT (type1);
529 type2 = TYPE_MAIN_VARIANT (type2);
531 /* If we would have to do structural comparison bail out. */
532 if (TYPE_STRUCTURAL_EQUALITY_P (type1)
533 || TYPE_STRUCTURAL_EQUALITY_P (type2))
536 /* Compare the canonical types. */
537 if (TYPE_CANONICAL (type1) == TYPE_CANONICAL (type2))
540 /* ??? Array types are not properly unified in all cases as we have
541 spurious changes in the index types for example. Removing this
542 causes all sorts of problems with the Fortran frontend. */
543 if (TREE_CODE (type1) == ARRAY_TYPE
544 && TREE_CODE (type2) == ARRAY_TYPE)
547 /* ??? In Ada, an lvalue of an unconstrained type can be used to access an
548 object of one of its constrained subtypes, e.g. when a function with an
549 unconstrained parameter passed by reference is called on an object and
550 inlined. But, even in the case of a fixed size, type and subtypes are
551 not equivalent enough as to share the same TYPE_CANONICAL, since this
552 would mean that conversions between them are useless, whereas they are
553 not (e.g. type and subtypes can have different modes). So, in the end,
554 they are only guaranteed to have the same alias set. */
555 if (get_alias_set (type1) == get_alias_set (type2))
558 /* The types are known to be not equal. */
562 /* Determine if the two component references REF1 and REF2 which are
563 based on access types TYPE1 and TYPE2 and of which at least one is based
564 on an indirect reference may alias. */
567 aliasing_component_refs_p (tree ref1, tree type1,
568 HOST_WIDE_INT offset1, HOST_WIDE_INT max_size1,
569 tree ref2, tree type2,
570 HOST_WIDE_INT offset2, HOST_WIDE_INT max_size2)
572 /* If one reference is a component references through pointers try to find a
573 common base and apply offset based disambiguation. This handles
575 struct A { int i; int j; } *q;
576 struct B { struct A a; int k; } *p;
577 disambiguating q->i and p->a.j. */
581 /* Now search for the type1 in the access path of ref2. This
582 would be a common base for doing offset based disambiguation on. */
584 while (handled_component_p (*refp)
585 && same_type_for_tbaa (TREE_TYPE (*refp), type1) == 0)
586 refp = &TREE_OPERAND (*refp, 0);
587 same_p = same_type_for_tbaa (TREE_TYPE (*refp), type1);
588 /* If we couldn't compare types we have to bail out. */
591 else if (same_p == 1)
593 HOST_WIDE_INT offadj, sztmp, msztmp;
594 get_ref_base_and_extent (*refp, &offadj, &sztmp, &msztmp);
596 return ranges_overlap_p (offset1, max_size1, offset2, max_size2);
598 /* If we didn't find a common base, try the other way around. */
600 while (handled_component_p (*refp)
601 && same_type_for_tbaa (TREE_TYPE (*refp), type2) == 0)
602 refp = &TREE_OPERAND (*refp, 0);
603 same_p = same_type_for_tbaa (TREE_TYPE (*refp), type2);
604 /* If we couldn't compare types we have to bail out. */
607 else if (same_p == 1)
609 HOST_WIDE_INT offadj, sztmp, msztmp;
610 get_ref_base_and_extent (*refp, &offadj, &sztmp, &msztmp);
612 return ranges_overlap_p (offset1, max_size1, offset2, max_size2);
614 /* If we have two type access paths B1.path1 and B2.path2 they may
615 only alias if either B1 is in B2.path2 or B2 is in B1.path1. */
619 /* Return true if two memory references based on the variables BASE1
620 and BASE2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and
621 [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. */
624 decl_refs_may_alias_p (tree base1,
625 HOST_WIDE_INT offset1, HOST_WIDE_INT max_size1,
627 HOST_WIDE_INT offset2, HOST_WIDE_INT max_size2)
629 gcc_assert (SSA_VAR_P (base1) && SSA_VAR_P (base2));
631 /* If both references are based on different variables, they cannot alias. */
635 /* If both references are based on the same variable, they cannot alias if
636 the accesses do not overlap. */
637 return ranges_overlap_p (offset1, max_size1, offset2, max_size2);
640 /* Return true if an indirect reference based on *PTR1 constrained
641 to [OFFSET1, OFFSET1 + MAX_SIZE1) may alias a variable based on BASE2
642 constrained to [OFFSET2, OFFSET2 + MAX_SIZE2). *PTR1 and BASE2 have
643 the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1
644 in which case they are computed on-demand. REF1 and REF2
645 if non-NULL are the complete memory reference trees. */
648 indirect_ref_may_alias_decl_p (tree ref1, tree ptr1,
649 HOST_WIDE_INT offset1, HOST_WIDE_INT max_size1,
650 alias_set_type base1_alias_set,
651 tree ref2, tree base2,
652 HOST_WIDE_INT offset2, HOST_WIDE_INT max_size2,
653 alias_set_type base2_alias_set)
655 /* If only one reference is based on a variable, they cannot alias if
656 the pointer access is beyond the extent of the variable access.
657 (the pointer base cannot validly point to an offset less than zero
659 They also cannot alias if the pointer may not point to the decl. */
661 && !ranges_overlap_p (offset1, max_size1, 0, offset2 + max_size2))
663 if (!ptr_deref_may_alias_decl_p (ptr1, base2))
666 /* Disambiguations that rely on strict aliasing rules follow. */
667 if (!flag_strict_aliasing)
670 /* If the alias set for a pointer access is zero all bets are off. */
671 if (base1_alias_set == -1)
672 base1_alias_set = get_deref_alias_set (ptr1);
673 if (base1_alias_set == 0)
675 if (base2_alias_set == -1)
676 base2_alias_set = get_alias_set (base2);
678 /* If both references are through the same type, they do not alias
679 if the accesses do not overlap. This does extra disambiguation
680 for mixed/pointer accesses but requires strict aliasing. */
681 if (same_type_for_tbaa (TREE_TYPE (TREE_TYPE (ptr1)),
682 TREE_TYPE (base2)) == 1)
683 return ranges_overlap_p (offset1, max_size1, offset2, max_size2);
685 /* The only way to access a variable is through a pointer dereference
686 of the same alias set or a subset of it. */
687 if (base1_alias_set != base2_alias_set
688 && !alias_set_subset_of (base1_alias_set, base2_alias_set))
691 /* Do access-path based disambiguation. */
693 && handled_component_p (ref1)
694 && handled_component_p (ref2))
695 return aliasing_component_refs_p (ref1, TREE_TYPE (TREE_TYPE (ptr1)),
697 ref2, TREE_TYPE (base2),
703 /* Return true if two indirect references based on *PTR1
704 and *PTR2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and
705 [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. *PTR1 and *PTR2 have
706 the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1
707 in which case they are computed on-demand. REF1 and REF2
708 if non-NULL are the complete memory reference trees. */
711 indirect_refs_may_alias_p (tree ref1, tree ptr1,
712 HOST_WIDE_INT offset1, HOST_WIDE_INT max_size1,
713 alias_set_type base1_alias_set,
714 tree ref2, tree ptr2,
715 HOST_WIDE_INT offset2, HOST_WIDE_INT max_size2,
716 alias_set_type base2_alias_set)
718 /* If both bases are based on pointers they cannot alias if they may not
719 point to the same memory object or if they point to the same object
720 and the accesses do not overlap. */
721 if (operand_equal_p (ptr1, ptr2, 0))
722 return ranges_overlap_p (offset1, max_size1, offset2, max_size2);
723 if (!ptr_derefs_may_alias_p (ptr1, ptr2))
726 /* Disambiguations that rely on strict aliasing rules follow. */
727 if (!flag_strict_aliasing)
730 /* If the alias set for a pointer access is zero all bets are off. */
731 if (base1_alias_set == -1)
732 base1_alias_set = get_deref_alias_set (ptr1);
733 if (base1_alias_set == 0)
735 if (base2_alias_set == -1)
736 base2_alias_set = get_deref_alias_set (ptr2);
737 if (base2_alias_set == 0)
740 /* If both references are through the same type, they do not alias
741 if the accesses do not overlap. This does extra disambiguation
742 for mixed/pointer accesses but requires strict aliasing. */
743 if (same_type_for_tbaa (TREE_TYPE (TREE_TYPE (ptr1)),
744 TREE_TYPE (TREE_TYPE (ptr2))) == 1)
745 return ranges_overlap_p (offset1, max_size1, offset2, max_size2);
747 /* Do type-based disambiguation. */
748 if (base1_alias_set != base2_alias_set
749 && !alias_sets_conflict_p (base1_alias_set, base2_alias_set))
752 /* Do access-path based disambiguation. */
754 && handled_component_p (ref1)
755 && handled_component_p (ref2))
756 return aliasing_component_refs_p (ref1, TREE_TYPE (TREE_TYPE (ptr1)),
758 ref2, TREE_TYPE (TREE_TYPE (ptr2)),
764 /* Return true, if the two memory references REF1 and REF2 may alias. */
767 refs_may_alias_p_1 (ao_ref *ref1, ao_ref *ref2, bool tbaa_p)
770 HOST_WIDE_INT offset1 = 0, offset2 = 0;
771 HOST_WIDE_INT max_size1 = -1, max_size2 = -1;
772 bool var1_p, var2_p, ind1_p, ind2_p;
775 gcc_assert ((!ref1->ref
776 || SSA_VAR_P (ref1->ref)
777 || handled_component_p (ref1->ref)
778 || INDIRECT_REF_P (ref1->ref)
779 || TREE_CODE (ref1->ref) == TARGET_MEM_REF
780 || TREE_CODE (ref1->ref) == CONST_DECL)
782 || SSA_VAR_P (ref2->ref)
783 || handled_component_p (ref2->ref)
784 || INDIRECT_REF_P (ref2->ref)
785 || TREE_CODE (ref2->ref) == TARGET_MEM_REF
786 || TREE_CODE (ref2->ref) == CONST_DECL));
788 /* Decompose the references into their base objects and the access. */
789 base1 = ao_ref_base (ref1);
790 offset1 = ref1->offset;
791 max_size1 = ref1->max_size;
792 base2 = ao_ref_base (ref2);
793 offset2 = ref2->offset;
794 max_size2 = ref2->max_size;
796 /* We can end up with registers or constants as bases for example from
797 *D.1663_44 = VIEW_CONVERT_EXPR<struct DB_LSN>(__tmp$B0F64_59);
798 which is seen as a struct copy. */
799 if (TREE_CODE (base1) == SSA_NAME
800 || TREE_CODE (base2) == SSA_NAME
801 || TREE_CODE (base1) == CONST_DECL
802 || TREE_CODE (base2) == CONST_DECL
803 || is_gimple_min_invariant (base1)
804 || is_gimple_min_invariant (base2))
807 /* We can end up refering to code via function decls. As we likely
808 do not properly track code aliases conservatively bail out. */
809 if (TREE_CODE (base1) == FUNCTION_DECL
810 || TREE_CODE (base2) == FUNCTION_DECL)
813 /* Defer to simple offset based disambiguation if we have
814 references based on two decls. Do this before defering to
815 TBAA to handle must-alias cases in conformance with the
816 GCC extension of allowing type-punning through unions. */
817 var1_p = SSA_VAR_P (base1);
818 var2_p = SSA_VAR_P (base2);
819 if (var1_p && var2_p)
820 return decl_refs_may_alias_p (base1, offset1, max_size1,
821 base2, offset2, max_size2);
823 ind1_p = INDIRECT_REF_P (base1);
824 ind2_p = INDIRECT_REF_P (base2);
825 /* Canonicalize the pointer-vs-decl case. */
826 if (ind1_p && var2_p)
831 tmp1 = offset1; offset1 = offset2; offset2 = tmp1;
832 tmp1 = max_size1; max_size1 = max_size2; max_size2 = tmp1;
833 tmp2 = base1; base1 = base2; base2 = tmp2;
834 tmp3 = ref1; ref1 = ref2; ref2 = tmp3;
841 /* If we are about to disambiguate pointer-vs-decl try harder to
842 see must-aliases and give leeway to some invalid cases.
843 This covers a pretty minimal set of cases only and does not
844 when called from the RTL oracle. It handles cases like
849 and also fixes gfortran.dg/lto/pr40725. */
852 && gimple_in_ssa_p (cfun)
853 && TREE_CODE (TREE_OPERAND (base2, 0)) == SSA_NAME)
855 gimple def_stmt = SSA_NAME_DEF_STMT (TREE_OPERAND (base2, 0));
856 while (is_gimple_assign (def_stmt)
857 && (gimple_assign_rhs_code (def_stmt) == SSA_NAME
858 || CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt))))
860 tree rhs = gimple_assign_rhs1 (def_stmt);
861 HOST_WIDE_INT offset, size, max_size;
863 /* Look through SSA name copies and pointer conversions. */
864 if (TREE_CODE (rhs) == SSA_NAME
865 && POINTER_TYPE_P (TREE_TYPE (rhs)))
867 def_stmt = SSA_NAME_DEF_STMT (rhs);
870 if (TREE_CODE (rhs) != ADDR_EXPR)
873 /* If the pointer is defined as an address based on a decl
874 use plain offset disambiguation and ignore TBAA. */
875 rhs = TREE_OPERAND (rhs, 0);
876 rhs = get_ref_base_and_extent (rhs, &offset, &size, &max_size);
884 return decl_refs_may_alias_p (base1, offset1, max_size1,
885 base2, offset2, max_size2);
888 /* Do not continue looking through &p->x to limit time
894 /* First defer to TBAA if possible. */
896 && flag_strict_aliasing
897 && !alias_sets_conflict_p (ao_ref_alias_set (ref1),
898 ao_ref_alias_set (ref2)))
901 /* If one reference is a TARGET_MEM_REF weird things are allowed. Still
902 TBAA disambiguation based on the access type is possible, so bail
903 out only after that check. */
904 if ((ref1->ref && TREE_CODE (ref1->ref) == TARGET_MEM_REF)
905 || (ref2->ref && TREE_CODE (ref2->ref) == TARGET_MEM_REF))
908 /* Dispatch to the pointer-vs-decl or pointer-vs-pointer disambiguators. */
909 set = tbaa_p ? -1 : 0;
910 if (var1_p && ind2_p)
911 return indirect_ref_may_alias_decl_p (ref2->ref, TREE_OPERAND (base2, 0),
912 offset2, max_size2, set,
914 offset1, max_size1, set);
915 else if (ind1_p && ind2_p)
916 return indirect_refs_may_alias_p (ref1->ref, TREE_OPERAND (base1, 0),
917 offset1, max_size1, set,
918 ref2->ref, TREE_OPERAND (base2, 0),
919 offset2, max_size2, set);
925 refs_may_alias_p (tree ref1, tree ref2)
929 ao_ref_init (&r1, ref1);
930 ao_ref_init (&r2, ref2);
931 res = refs_may_alias_p_1 (&r1, &r2, true);
933 ++alias_stats.refs_may_alias_p_may_alias;
935 ++alias_stats.refs_may_alias_p_no_alias;
939 /* Returns true if there is a anti-dependence for the STORE that
940 executes after the LOAD. */
943 refs_anti_dependent_p (tree load, tree store)
946 ao_ref_init (&r1, load);
947 ao_ref_init (&r2, store);
948 return refs_may_alias_p_1 (&r1, &r2, false);
951 /* Returns true if there is a output dependence for the stores
952 STORE1 and STORE2. */
955 refs_output_dependent_p (tree store1, tree store2)
958 ao_ref_init (&r1, store1);
959 ao_ref_init (&r2, store2);
960 return refs_may_alias_p_1 (&r1, &r2, false);
963 /* If the call CALL may use the memory reference REF return true,
964 otherwise return false. */
967 ref_maybe_used_by_call_p_1 (gimple call, ao_ref *ref)
971 int flags = gimple_call_flags (call);
973 /* Const functions without a static chain do not implicitly use memory. */
974 if (!gimple_call_chain (call)
975 && (flags & (ECF_CONST|ECF_NOVOPS)))
978 base = ao_ref_base (ref);
982 /* If the reference is based on a decl that is not aliased the call
983 cannot possibly use it. */
985 && !may_be_aliased (base)
986 /* But local statics can be used through recursion. */
987 && !is_global_var (base))
990 callee = gimple_call_fndecl (call);
992 /* Handle those builtin functions explicitly that do not act as
993 escape points. See tree-ssa-structalias.c:find_func_aliases
994 for the list of builtins we might need to handle here. */
995 if (callee != NULL_TREE
996 && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL)
997 switch (DECL_FUNCTION_CODE (callee))
999 /* All the following functions clobber memory pointed to by
1000 their first argument. */
1001 case BUILT_IN_STRCPY:
1002 case BUILT_IN_STRNCPY:
1003 case BUILT_IN_MEMCPY:
1004 case BUILT_IN_MEMMOVE:
1005 case BUILT_IN_MEMPCPY:
1006 case BUILT_IN_STPCPY:
1007 case BUILT_IN_STPNCPY:
1008 case BUILT_IN_STRCAT:
1009 case BUILT_IN_STRNCAT:
1012 tree size = NULL_TREE;
1013 if (gimple_call_num_args (call) == 3)
1014 size = gimple_call_arg (call, 2);
1015 ao_ref_init_from_ptr_and_size (&dref,
1016 gimple_call_arg (call, 1),
1018 return refs_may_alias_p_1 (&dref, ref, false);
1020 case BUILT_IN_BCOPY:
1023 tree size = gimple_call_arg (call, 2);
1024 ao_ref_init_from_ptr_and_size (&dref,
1025 gimple_call_arg (call, 0),
1027 return refs_may_alias_p_1 (&dref, ref, false);
1029 /* The following builtins do not read from memory. */
1031 case BUILT_IN_MALLOC:
1032 case BUILT_IN_CALLOC:
1033 case BUILT_IN_MEMSET:
1034 case BUILT_IN_FREXP:
1035 case BUILT_IN_FREXPF:
1036 case BUILT_IN_FREXPL:
1037 case BUILT_IN_GAMMA_R:
1038 case BUILT_IN_GAMMAF_R:
1039 case BUILT_IN_GAMMAL_R:
1040 case BUILT_IN_LGAMMA_R:
1041 case BUILT_IN_LGAMMAF_R:
1042 case BUILT_IN_LGAMMAL_R:
1044 case BUILT_IN_MODFF:
1045 case BUILT_IN_MODFL:
1046 case BUILT_IN_REMQUO:
1047 case BUILT_IN_REMQUOF:
1048 case BUILT_IN_REMQUOL:
1049 case BUILT_IN_SINCOS:
1050 case BUILT_IN_SINCOSF:
1051 case BUILT_IN_SINCOSL:
1055 /* Fallthru to general call handling. */;
1058 /* Check if base is a global static variable that is not read
1060 if (TREE_CODE (base) == VAR_DECL
1061 && TREE_STATIC (base)
1062 && !TREE_PUBLIC (base))
1066 if (callee != NULL_TREE
1068 = ipa_reference_get_not_read_global (cgraph_node (callee)))
1069 && bitmap_bit_p (not_read, DECL_UID (base)))
1073 /* If the base variable is call-used or call-clobbered then
1075 if (flags & (ECF_PURE|ECF_CONST|ECF_LOOPING_CONST_OR_PURE|ECF_NOVOPS))
1079 if (is_call_used (base))
1082 else if (INDIRECT_REF_P (base)
1083 && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME)
1085 struct ptr_info_def *pi = SSA_NAME_PTR_INFO (TREE_OPERAND (base, 0));
1089 if (pt_solution_includes_global (&pi->pt)
1090 || pt_solutions_intersect (&cfun->gimple_df->callused, &pi->pt)
1091 || pt_solutions_intersect (&cfun->gimple_df->escaped, &pi->pt))
1101 if (is_call_clobbered (base))
1104 else if (INDIRECT_REF_P (base)
1105 && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME)
1107 struct ptr_info_def *pi = SSA_NAME_PTR_INFO (TREE_OPERAND (base, 0));
1111 if (pt_solution_includes_global (&pi->pt)
1112 || pt_solutions_intersect (&cfun->gimple_df->escaped, &pi->pt))
1119 /* Inspect call arguments for passed-by-value aliases. */
1121 for (i = 0; i < gimple_call_num_args (call); ++i)
1123 tree op = gimple_call_arg (call, i);
1125 if (TREE_CODE (op) == WITH_SIZE_EXPR)
1126 op = TREE_OPERAND (op, 0);
1128 if (TREE_CODE (op) != SSA_NAME
1129 && !is_gimple_min_invariant (op))
1132 ao_ref_init (&r, op);
1133 if (refs_may_alias_p_1 (&r, ref, true))
1142 ref_maybe_used_by_call_p (gimple call, tree ref)
1146 ao_ref_init (&r, ref);
1147 res = ref_maybe_used_by_call_p_1 (call, &r);
1149 ++alias_stats.ref_maybe_used_by_call_p_may_alias;
1151 ++alias_stats.ref_maybe_used_by_call_p_no_alias;
1156 /* If the statement STMT may use the memory reference REF return
1157 true, otherwise return false. */
1160 ref_maybe_used_by_stmt_p (gimple stmt, tree ref)
1162 if (is_gimple_assign (stmt))
1166 /* All memory assign statements are single. */
1167 if (!gimple_assign_single_p (stmt))
1170 rhs = gimple_assign_rhs1 (stmt);
1171 if (is_gimple_reg (rhs)
1172 || is_gimple_min_invariant (rhs)
1173 || gimple_assign_rhs_code (stmt) == CONSTRUCTOR)
1176 return refs_may_alias_p (rhs, ref);
1178 else if (is_gimple_call (stmt))
1179 return ref_maybe_used_by_call_p (stmt, ref);
1184 /* If the call in statement CALL may clobber the memory reference REF
1185 return true, otherwise return false. */
1188 call_may_clobber_ref_p_1 (gimple call, ao_ref *ref)
1193 /* If the call is pure or const it cannot clobber anything. */
1194 if (gimple_call_flags (call)
1195 & (ECF_PURE|ECF_CONST|ECF_LOOPING_CONST_OR_PURE|ECF_NOVOPS))
1198 base = ao_ref_base (ref);
1202 if (TREE_CODE (base) == SSA_NAME
1203 || CONSTANT_CLASS_P (base))
1206 /* If the reference is based on a decl that is not aliased the call
1207 cannot possibly clobber it. */
1209 && !may_be_aliased (base)
1210 /* But local non-readonly statics can be modified through recursion
1211 or the call may implement a threading barrier which we must
1212 treat as may-def. */
1213 && (TREE_READONLY (base)
1214 || !is_global_var (base)))
1217 callee = gimple_call_fndecl (call);
1219 /* Handle those builtin functions explicitly that do not act as
1220 escape points. See tree-ssa-structalias.c:find_func_aliases
1221 for the list of builtins we might need to handle here. */
1222 if (callee != NULL_TREE
1223 && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL)
1224 switch (DECL_FUNCTION_CODE (callee))
1226 /* All the following functions clobber memory pointed to by
1227 their first argument. */
1228 case BUILT_IN_STRCPY:
1229 case BUILT_IN_STRNCPY:
1230 case BUILT_IN_MEMCPY:
1231 case BUILT_IN_MEMMOVE:
1232 case BUILT_IN_MEMPCPY:
1233 case BUILT_IN_STPCPY:
1234 case BUILT_IN_STPNCPY:
1235 case BUILT_IN_STRCAT:
1236 case BUILT_IN_STRNCAT:
1237 case BUILT_IN_MEMSET:
1240 tree size = NULL_TREE;
1241 if (gimple_call_num_args (call) == 3)
1242 size = gimple_call_arg (call, 2);
1243 ao_ref_init_from_ptr_and_size (&dref,
1244 gimple_call_arg (call, 0),
1246 return refs_may_alias_p_1 (&dref, ref, false);
1248 case BUILT_IN_BCOPY:
1251 tree size = gimple_call_arg (call, 2);
1252 ao_ref_init_from_ptr_and_size (&dref,
1253 gimple_call_arg (call, 1),
1255 return refs_may_alias_p_1 (&dref, ref, false);
1257 /* Allocating memory does not have any side-effects apart from
1258 being the definition point for the pointer. */
1259 case BUILT_IN_MALLOC:
1260 case BUILT_IN_CALLOC:
1261 /* Unix98 specifies that errno is set on allocation failure.
1262 Until we properly can track the errno location assume it
1263 is not a local decl but external or anonymous storage in
1264 a different translation unit. Also assume it is of
1265 type int as required by the standard. */
1267 && TREE_TYPE (base) == integer_type_node)
1269 struct ptr_info_def *pi;
1271 && !TREE_STATIC (base))
1273 else if (INDIRECT_REF_P (base)
1274 && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME
1275 && (pi = SSA_NAME_PTR_INFO (TREE_OPERAND (base, 0))))
1276 return pi->pt.anything || pi->pt.nonlocal;
1279 /* Freeing memory kills the pointed-to memory. More importantly
1280 the call has to serve as a barrier for moving loads and stores
1284 tree ptr = gimple_call_arg (call, 0);
1285 return ptr_deref_may_alias_ref_p_1 (ptr, ref);
1287 case BUILT_IN_GAMMA_R:
1288 case BUILT_IN_GAMMAF_R:
1289 case BUILT_IN_GAMMAL_R:
1290 case BUILT_IN_LGAMMA_R:
1291 case BUILT_IN_LGAMMAF_R:
1292 case BUILT_IN_LGAMMAL_R:
1294 tree out = gimple_call_arg (call, 1);
1295 if (ptr_deref_may_alias_ref_p_1 (out, ref))
1297 if (flag_errno_math)
1301 case BUILT_IN_FREXP:
1302 case BUILT_IN_FREXPF:
1303 case BUILT_IN_FREXPL:
1305 case BUILT_IN_MODFF:
1306 case BUILT_IN_MODFL:
1308 tree out = gimple_call_arg (call, 1);
1309 return ptr_deref_may_alias_ref_p_1 (out, ref);
1311 case BUILT_IN_REMQUO:
1312 case BUILT_IN_REMQUOF:
1313 case BUILT_IN_REMQUOL:
1315 tree out = gimple_call_arg (call, 2);
1316 if (ptr_deref_may_alias_ref_p_1 (out, ref))
1318 if (flag_errno_math)
1322 case BUILT_IN_SINCOS:
1323 case BUILT_IN_SINCOSF:
1324 case BUILT_IN_SINCOSL:
1326 tree sin = gimple_call_arg (call, 1);
1327 tree cos = gimple_call_arg (call, 2);
1328 return (ptr_deref_may_alias_ref_p_1 (sin, ref)
1329 || ptr_deref_may_alias_ref_p_1 (cos, ref));
1332 /* Fallthru to general call handling. */;
1335 /* Check if base is a global static variable that is not written
1337 if (callee != NULL_TREE
1338 && TREE_CODE (base) == VAR_DECL
1339 && TREE_STATIC (base)
1340 && !TREE_PUBLIC (base))
1345 = ipa_reference_get_not_written_global (cgraph_node (callee)))
1346 && bitmap_bit_p (not_written, DECL_UID (base)))
1351 return is_call_clobbered (base);
1352 else if (INDIRECT_REF_P (base)
1353 && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME)
1355 struct ptr_info_def *pi = SSA_NAME_PTR_INFO (TREE_OPERAND (base, 0));
1359 return (pt_solution_includes_global (&pi->pt)
1360 || pt_solutions_intersect (&cfun->gimple_df->escaped, &pi->pt));
1366 static bool ATTRIBUTE_UNUSED
1367 call_may_clobber_ref_p (gimple call, tree ref)
1371 ao_ref_init (&r, ref);
1372 res = call_may_clobber_ref_p_1 (call, &r);
1374 ++alias_stats.call_may_clobber_ref_p_may_alias;
1376 ++alias_stats.call_may_clobber_ref_p_no_alias;
1381 /* If the statement STMT may clobber the memory reference REF return true,
1382 otherwise return false. */
1385 stmt_may_clobber_ref_p_1 (gimple stmt, ao_ref *ref)
1387 if (is_gimple_call (stmt))
1389 tree lhs = gimple_call_lhs (stmt);
1391 && !is_gimple_reg (lhs))
1394 ao_ref_init (&r, lhs);
1395 if (refs_may_alias_p_1 (ref, &r, true))
1399 return call_may_clobber_ref_p_1 (stmt, ref);
1401 else if (is_gimple_assign (stmt))
1404 ao_ref_init (&r, gimple_assign_lhs (stmt));
1405 return refs_may_alias_p_1 (ref, &r, true);
1407 else if (gimple_code (stmt) == GIMPLE_ASM)
1414 stmt_may_clobber_ref_p (gimple stmt, tree ref)
1417 ao_ref_init (&r, ref);
1418 return stmt_may_clobber_ref_p_1 (stmt, &r);
1422 /* Walk the virtual use-def chain of VUSE until hitting the virtual operand
1423 TARGET or a statement clobbering the memory reference REF in which
1424 case false is returned. The walk starts with VUSE, one argument of PHI. */
1427 maybe_skip_until (gimple phi, tree target, ao_ref *ref,
1428 tree vuse, bitmap *visited)
1431 *visited = BITMAP_ALLOC (NULL);
1433 bitmap_set_bit (*visited, SSA_NAME_VERSION (PHI_RESULT (phi)));
1435 /* Walk until we hit the target. */
1436 while (vuse != target)
1438 gimple def_stmt = SSA_NAME_DEF_STMT (vuse);
1439 /* Recurse for PHI nodes. */
1440 if (gimple_code (def_stmt) == GIMPLE_PHI)
1442 /* An already visited PHI node ends the walk successfully. */
1443 if (bitmap_bit_p (*visited, SSA_NAME_VERSION (PHI_RESULT (def_stmt))))
1445 vuse = get_continuation_for_phi (def_stmt, ref, visited);
1450 /* A clobbering statement or the end of the IL ends it failing. */
1451 else if (gimple_nop_p (def_stmt)
1452 || stmt_may_clobber_ref_p_1 (def_stmt, ref))
1454 vuse = gimple_vuse (def_stmt);
1459 /* Starting from a PHI node for the virtual operand of the memory reference
1460 REF find a continuation virtual operand that allows to continue walking
1461 statements dominating PHI skipping only statements that cannot possibly
1462 clobber REF. Returns NULL_TREE if no suitable virtual operand can
1466 get_continuation_for_phi (gimple phi, ao_ref *ref, bitmap *visited)
1468 unsigned nargs = gimple_phi_num_args (phi);
1470 /* Through a single-argument PHI we can simply look through. */
1472 return PHI_ARG_DEF (phi, 0);
1474 /* For two arguments try to skip non-aliasing code until we hit
1475 the phi argument definition that dominates the other one. */
1478 tree arg0 = PHI_ARG_DEF (phi, 0);
1479 tree arg1 = PHI_ARG_DEF (phi, 1);
1480 gimple def0 = SSA_NAME_DEF_STMT (arg0);
1481 gimple def1 = SSA_NAME_DEF_STMT (arg1);
1486 else if (gimple_nop_p (def0)
1487 || (!gimple_nop_p (def1)
1488 && dominated_by_p (CDI_DOMINATORS,
1489 gimple_bb (def1), gimple_bb (def0))))
1491 if (maybe_skip_until (phi, arg0, ref, arg1, visited))
1494 else if (gimple_nop_p (def1)
1495 || dominated_by_p (CDI_DOMINATORS,
1496 gimple_bb (def0), gimple_bb (def1)))
1498 if (maybe_skip_until (phi, arg1, ref, arg0, visited))
1501 /* Special case of a diamond:
1503 goto (cond) ? L1 : L2
1504 L1: store1 = ... #MEM_2 = vuse(MEM_1)
1506 L2: store2 = ... #MEM_3 = vuse(MEM_1)
1507 L3: MEM_4 = PHI<MEM_2, MEM_3>
1508 We were called with the PHI at L3, MEM_2 and MEM_3 don't
1509 dominate each other, but still we can easily skip this PHI node
1510 if we recognize that the vuse MEM operand is the same for both,
1511 and that we can skip both statements (they don't clobber us).
1512 This is still linear. Don't use maybe_skip_until, that might
1513 potentially be slow. */
1514 else if ((common_vuse = gimple_vuse (def0))
1515 && common_vuse == gimple_vuse (def1))
1517 if (!stmt_may_clobber_ref_p_1 (def0, ref)
1518 && !stmt_may_clobber_ref_p_1 (def1, ref))
1526 /* Based on the memory reference REF and its virtual use VUSE call
1527 WALKER for each virtual use that is equivalent to VUSE, including VUSE
1528 itself. That is, for each virtual use for which its defining statement
1529 does not clobber REF.
1531 WALKER is called with REF, the current virtual use and DATA. If
1532 WALKER returns non-NULL the walk stops and its result is returned.
1533 At the end of a non-successful walk NULL is returned.
1535 TRANSLATE if non-NULL is called with a pointer to REF, the virtual
1536 use which definition is a statement that may clobber REF and DATA.
1537 If TRANSLATE returns (void *)-1 the walk stops and NULL is returned.
1538 If TRANSLATE returns non-NULL the walk stops and its result is returned.
1539 If TRANSLATE returns NULL the walk continues and TRANSLATE is supposed
1540 to adjust REF and *DATA to make that valid.
1542 TODO: Cache the vector of equivalent vuses per ref, vuse pair. */
1545 walk_non_aliased_vuses (ao_ref *ref, tree vuse,
1546 void *(*walker)(ao_ref *, tree, void *),
1547 void *(*translate)(ao_ref *, tree, void *), void *data)
1549 bitmap visited = NULL;
1552 timevar_push (TV_ALIAS_STMT_WALK);
1558 /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */
1559 res = (*walker) (ref, vuse, data);
1563 def_stmt = SSA_NAME_DEF_STMT (vuse);
1564 if (gimple_nop_p (def_stmt))
1566 else if (gimple_code (def_stmt) == GIMPLE_PHI)
1567 vuse = get_continuation_for_phi (def_stmt, ref, &visited);
1570 if (stmt_may_clobber_ref_p_1 (def_stmt, ref))
1574 res = (*translate) (ref, vuse, data);
1575 /* Failed lookup and translation. */
1576 if (res == (void *)-1)
1581 /* Lookup succeeded. */
1582 else if (res != NULL)
1584 /* Translation succeeded, continue walking. */
1586 vuse = gimple_vuse (def_stmt);
1592 BITMAP_FREE (visited);
1594 timevar_pop (TV_ALIAS_STMT_WALK);
1600 /* Based on the memory reference REF call WALKER for each vdef which
1601 defining statement may clobber REF, starting with VDEF. If REF
1602 is NULL_TREE, each defining statement is visited.
1604 WALKER is called with REF, the current vdef and DATA. If WALKER
1605 returns true the walk is stopped, otherwise it continues.
1607 At PHI nodes walk_aliased_vdefs forks into one walk for reach
1608 PHI argument (but only one walk continues on merge points), the
1609 return value is true if any of the walks was successful.
1611 The function returns the number of statements walked. */
1614 walk_aliased_vdefs_1 (ao_ref *ref, tree vdef,
1615 bool (*walker)(ao_ref *, tree, void *), void *data,
1616 bitmap *visited, unsigned int cnt)
1620 gimple def_stmt = SSA_NAME_DEF_STMT (vdef);
1623 && !bitmap_set_bit (*visited, SSA_NAME_VERSION (vdef)))
1626 if (gimple_nop_p (def_stmt))
1628 else if (gimple_code (def_stmt) == GIMPLE_PHI)
1632 *visited = BITMAP_ALLOC (NULL);
1633 for (i = 0; i < gimple_phi_num_args (def_stmt); ++i)
1634 cnt += walk_aliased_vdefs_1 (ref, gimple_phi_arg_def (def_stmt, i),
1635 walker, data, visited, 0);
1639 /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */
1642 || stmt_may_clobber_ref_p_1 (def_stmt, ref))
1643 && (*walker) (ref, vdef, data))
1646 vdef = gimple_vuse (def_stmt);
1652 walk_aliased_vdefs (ao_ref *ref, tree vdef,
1653 bool (*walker)(ao_ref *, tree, void *), void *data,
1656 bitmap local_visited = NULL;
1659 timevar_push (TV_ALIAS_STMT_WALK);
1661 ret = walk_aliased_vdefs_1 (ref, vdef, walker, data,
1662 visited ? visited : &local_visited, 0);
1664 BITMAP_FREE (local_visited);
1666 timevar_pop (TV_ALIAS_STMT_WALK);