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"
28 #include "basic-block.h"
31 #include "langhooks.h"
35 #include "tree-pretty-print.h"
36 #include "tree-dump.h"
38 #include "tree-flow.h"
39 #include "tree-inline.h"
40 #include "tree-pass.h"
43 #include "ipa-type-escape.h"
47 #include "pointer-set.h"
48 #include "alloc-pool.h"
49 #include "tree-ssa-alias.h"
51 /* Broad overview of how alias analysis on gimple works:
53 Statements clobbering or using memory are linked through the
54 virtual operand factored use-def chain. The virtual operand
55 is unique per function, its symbol is accessible via gimple_vop (cfun).
56 Virtual operands are used for efficiently walking memory statements
57 in the gimple IL and are useful for things like value-numbering as
58 a generation count for memory references.
60 SSA_NAME pointers may have associated points-to information
61 accessible via the SSA_NAME_PTR_INFO macro. Flow-insensitive
62 points-to information is (re-)computed by the TODO_rebuild_alias
63 pass manager todo. Points-to information is also used for more
64 precise tracking of call-clobbered and call-used variables and
65 related disambiguations.
67 This file contains functions for disambiguating memory references,
68 the so called alias-oracle and tools for walking of the gimple IL.
70 The main alias-oracle entry-points are
72 bool stmt_may_clobber_ref_p (gimple, tree)
74 This function queries if a statement may invalidate (parts of)
75 the memory designated by the reference tree argument.
77 bool ref_maybe_used_by_stmt_p (gimple, tree)
79 This function queries if a statement may need (parts of) the
80 memory designated by the reference tree argument.
82 There are variants of these functions that only handle the call
83 part of a statement, call_may_clobber_ref_p and ref_maybe_used_by_call_p.
84 Note that these do not disambiguate against a possible call lhs.
86 bool refs_may_alias_p (tree, tree)
88 This function tries to disambiguate two reference trees.
90 bool ptr_deref_may_alias_global_p (tree)
92 This function queries if dereferencing a pointer variable may
95 More low-level disambiguators are available and documented in
96 this file. Low-level disambiguators dealing with points-to
97 information are in tree-ssa-structalias.c. */
100 /* Query statistics for the different low-level disambiguators.
101 A high-level query may trigger multiple of them. */
104 unsigned HOST_WIDE_INT refs_may_alias_p_may_alias;
105 unsigned HOST_WIDE_INT refs_may_alias_p_no_alias;
106 unsigned HOST_WIDE_INT ref_maybe_used_by_call_p_may_alias;
107 unsigned HOST_WIDE_INT ref_maybe_used_by_call_p_no_alias;
108 unsigned HOST_WIDE_INT call_may_clobber_ref_p_may_alias;
109 unsigned HOST_WIDE_INT call_may_clobber_ref_p_no_alias;
113 dump_alias_stats (FILE *s)
115 fprintf (s, "\nAlias oracle query stats:\n");
116 fprintf (s, " refs_may_alias_p: "
117 HOST_WIDE_INT_PRINT_DEC" disambiguations, "
118 HOST_WIDE_INT_PRINT_DEC" queries\n",
119 alias_stats.refs_may_alias_p_no_alias,
120 alias_stats.refs_may_alias_p_no_alias
121 + alias_stats.refs_may_alias_p_may_alias);
122 fprintf (s, " ref_maybe_used_by_call_p: "
123 HOST_WIDE_INT_PRINT_DEC" disambiguations, "
124 HOST_WIDE_INT_PRINT_DEC" queries\n",
125 alias_stats.ref_maybe_used_by_call_p_no_alias,
126 alias_stats.refs_may_alias_p_no_alias
127 + alias_stats.ref_maybe_used_by_call_p_may_alias);
128 fprintf (s, " call_may_clobber_ref_p: "
129 HOST_WIDE_INT_PRINT_DEC" disambiguations, "
130 HOST_WIDE_INT_PRINT_DEC" queries\n",
131 alias_stats.call_may_clobber_ref_p_no_alias,
132 alias_stats.call_may_clobber_ref_p_no_alias
133 + alias_stats.call_may_clobber_ref_p_may_alias);
137 /* Return true, if dereferencing PTR may alias with a global variable. */
140 ptr_deref_may_alias_global_p (tree ptr)
142 struct ptr_info_def *pi;
144 /* If we end up with a pointer constant here that may point
146 if (TREE_CODE (ptr) != SSA_NAME)
149 pi = SSA_NAME_PTR_INFO (ptr);
151 /* If we do not have points-to information for this variable,
156 /* ??? This does not use TBAA to prune globals ptr may not access. */
157 return pt_solution_includes_global (&pi->pt);
160 /* Return true if dereferencing PTR may alias DECL.
161 The caller is responsible for applying TBAA to see if PTR
162 may access DECL at all. */
165 ptr_deref_may_alias_decl_p (tree ptr, tree decl)
167 struct ptr_info_def *pi;
169 gcc_assert ((TREE_CODE (ptr) == SSA_NAME
170 || TREE_CODE (ptr) == ADDR_EXPR
171 || TREE_CODE (ptr) == INTEGER_CST)
172 && (TREE_CODE (decl) == VAR_DECL
173 || TREE_CODE (decl) == PARM_DECL
174 || TREE_CODE (decl) == RESULT_DECL));
176 /* Non-aliased variables can not be pointed to. */
177 if (!may_be_aliased (decl))
180 /* ADDR_EXPR pointers either just offset another pointer or directly
181 specify the pointed-to set. */
182 if (TREE_CODE (ptr) == ADDR_EXPR)
184 tree base = get_base_address (TREE_OPERAND (ptr, 0));
186 && (INDIRECT_REF_P (base)
187 || TREE_CODE (base) == MEM_REF))
188 ptr = TREE_OPERAND (base, 0);
193 && CONSTANT_CLASS_P (base))
199 /* We can end up with dereferencing constant pointers.
200 Just bail out in this case. */
201 if (TREE_CODE (ptr) == INTEGER_CST)
204 /* If we do not have useful points-to information for this pointer
205 we cannot disambiguate anything else. */
206 pi = SSA_NAME_PTR_INFO (ptr);
210 /* If the decl can be used as a restrict tag and we have a restrict
211 pointer and that pointers points-to set doesn't contain this decl
212 then they can't alias. */
213 if (DECL_RESTRICTED_P (decl)
214 && TYPE_RESTRICT (TREE_TYPE (ptr))
215 && pi->pt.vars_contains_restrict)
216 return bitmap_bit_p (pi->pt.vars, DECL_PT_UID (decl));
218 return pt_solution_includes (&pi->pt, decl);
221 /* Return true if dereferenced PTR1 and PTR2 may alias.
222 The caller is responsible for applying TBAA to see if accesses
223 through PTR1 and PTR2 may conflict at all. */
226 ptr_derefs_may_alias_p (tree ptr1, tree ptr2)
228 struct ptr_info_def *pi1, *pi2;
230 gcc_assert ((TREE_CODE (ptr1) == SSA_NAME
231 || TREE_CODE (ptr1) == ADDR_EXPR
232 || TREE_CODE (ptr1) == INTEGER_CST)
233 && (TREE_CODE (ptr2) == SSA_NAME
234 || TREE_CODE (ptr2) == ADDR_EXPR
235 || TREE_CODE (ptr2) == INTEGER_CST));
237 /* ADDR_EXPR pointers either just offset another pointer or directly
238 specify the pointed-to set. */
239 if (TREE_CODE (ptr1) == ADDR_EXPR)
241 tree base = get_base_address (TREE_OPERAND (ptr1, 0));
243 && (INDIRECT_REF_P (base)
244 || TREE_CODE (base) == MEM_REF))
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 || TREE_CODE (base) == MEM_REF))
258 ptr2 = TREE_OPERAND (base, 0);
261 return ptr_deref_may_alias_decl_p (ptr1, base);
266 /* We can end up with dereferencing constant pointers.
267 Just bail out in this case. */
268 if (TREE_CODE (ptr1) == INTEGER_CST
269 || TREE_CODE (ptr2) == INTEGER_CST)
272 /* We may end up with two empty points-to solutions for two same pointers.
273 In this case we still want to say both pointers alias, so shortcut
278 /* If we do not have useful points-to information for either pointer
279 we cannot disambiguate anything else. */
280 pi1 = SSA_NAME_PTR_INFO (ptr1);
281 pi2 = SSA_NAME_PTR_INFO (ptr2);
285 /* If both pointers are restrict-qualified try to disambiguate
286 with restrict information. */
287 if (TYPE_RESTRICT (TREE_TYPE (ptr1))
288 && TYPE_RESTRICT (TREE_TYPE (ptr2))
289 && !pt_solutions_same_restrict_base (&pi1->pt, &pi2->pt))
292 /* ??? This does not use TBAA to prune decls from the intersection
293 that not both pointers may access. */
294 return pt_solutions_intersect (&pi1->pt, &pi2->pt);
297 /* Return true if dereferencing PTR may alias *REF.
298 The caller is responsible for applying TBAA to see if PTR
299 may access *REF at all. */
302 ptr_deref_may_alias_ref_p_1 (tree ptr, ao_ref *ref)
304 tree base = ao_ref_base (ref);
306 if (INDIRECT_REF_P (base)
307 || TREE_CODE (base) == MEM_REF)
308 return ptr_derefs_may_alias_p (ptr, TREE_OPERAND (base, 0));
309 else if (SSA_VAR_P (base))
310 return ptr_deref_may_alias_decl_p (ptr, base);
316 /* Dump alias information on FILE. */
319 dump_alias_info (FILE *file)
323 = lang_hooks.decl_printable_name (current_function_decl, 2);
324 referenced_var_iterator rvi;
327 fprintf (file, "\n\nAlias information for %s\n\n", funcname);
329 fprintf (file, "Aliased symbols\n\n");
331 FOR_EACH_REFERENCED_VAR (var, rvi)
333 if (may_be_aliased (var))
334 dump_variable (file, var);
337 fprintf (file, "\nCall clobber information\n");
339 fprintf (file, "\nESCAPED");
340 dump_points_to_solution (file, &cfun->gimple_df->escaped);
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 /* Dump the points-to set *PT into FILE. */
374 dump_points_to_solution (FILE *file, struct pt_solution *pt)
377 fprintf (file, ", points-to anything");
380 fprintf (file, ", points-to non-local");
383 fprintf (file, ", points-to escaped");
386 fprintf (file, ", points-to unit escaped");
389 fprintf (file, ", points-to NULL");
393 fprintf (file, ", points-to vars: ");
394 dump_decl_set (file, pt->vars);
395 if (pt->vars_contains_global)
396 fprintf (file, " (includes global vars)");
397 if (pt->vars_contains_restrict)
398 fprintf (file, " (includes restrict tags)");
402 /* Dump points-to information for SSA_NAME PTR into FILE. */
405 dump_points_to_info_for (FILE *file, tree ptr)
407 struct ptr_info_def *pi = SSA_NAME_PTR_INFO (ptr);
409 print_generic_expr (file, ptr, dump_flags);
412 dump_points_to_solution (file, &pi->pt);
414 fprintf (file, ", points-to anything");
416 fprintf (file, "\n");
420 /* Dump points-to information for VAR into stderr. */
423 debug_points_to_info_for (tree var)
425 dump_points_to_info_for (stderr, var);
429 /* Initializes the alias-oracle reference representation *R from REF. */
432 ao_ref_init (ao_ref *r, tree ref)
439 r->ref_alias_set = -1;
440 r->base_alias_set = -1;
443 /* Returns the base object of the memory reference *REF. */
446 ao_ref_base (ao_ref *ref)
450 ref->base = get_ref_base_and_extent (ref->ref, &ref->offset, &ref->size,
455 /* Returns the base object alias set of the memory reference *REF. */
457 static alias_set_type
458 ao_ref_base_alias_set (ao_ref *ref)
461 if (ref->base_alias_set != -1)
462 return ref->base_alias_set;
466 while (handled_component_p (base_ref))
467 base_ref = TREE_OPERAND (base_ref, 0);
468 ref->base_alias_set = get_alias_set (base_ref);
469 return ref->base_alias_set;
472 /* Returns the reference alias set of the memory reference *REF. */
475 ao_ref_alias_set (ao_ref *ref)
477 if (ref->ref_alias_set != -1)
478 return ref->ref_alias_set;
479 ref->ref_alias_set = get_alias_set (ref->ref);
480 return ref->ref_alias_set;
483 /* Init an alias-oracle reference representation from a gimple pointer
484 PTR and a gimple size SIZE in bytes. If SIZE is NULL_TREE the the
485 size is assumed to be unknown. The access is assumed to be only
486 to or after of the pointer target, not before it. */
489 ao_ref_init_from_ptr_and_size (ao_ref *ref, tree ptr, tree size)
491 HOST_WIDE_INT t1, t2;
492 ref->ref = NULL_TREE;
493 if (TREE_CODE (ptr) == ADDR_EXPR)
494 ref->base = get_ref_base_and_extent (TREE_OPERAND (ptr, 0),
495 &ref->offset, &t1, &t2);
498 ref->base = build2 (MEM_REF, char_type_node,
499 ptr, null_pointer_node);
503 && host_integerp (size, 0)
504 && TREE_INT_CST_LOW (size) * 8 / 8 == TREE_INT_CST_LOW (size))
505 ref->max_size = ref->size = TREE_INT_CST_LOW (size) * 8;
507 ref->max_size = ref->size = -1;
508 ref->ref_alias_set = 0;
509 ref->base_alias_set = 0;
512 /* Return 1 if TYPE1 and TYPE2 are to be considered equivalent for the
513 purpose of TBAA. Return 0 if they are distinct and -1 if we cannot
517 same_type_for_tbaa (tree type1, tree type2)
519 type1 = TYPE_MAIN_VARIANT (type1);
520 type2 = TYPE_MAIN_VARIANT (type2);
522 /* If we would have to do structural comparison bail out. */
523 if (TYPE_STRUCTURAL_EQUALITY_P (type1)
524 || TYPE_STRUCTURAL_EQUALITY_P (type2))
527 /* Compare the canonical types. */
528 if (TYPE_CANONICAL (type1) == TYPE_CANONICAL (type2))
531 /* ??? Array types are not properly unified in all cases as we have
532 spurious changes in the index types for example. Removing this
533 causes all sorts of problems with the Fortran frontend. */
534 if (TREE_CODE (type1) == ARRAY_TYPE
535 && TREE_CODE (type2) == ARRAY_TYPE)
538 /* ??? In Ada, an lvalue of an unconstrained type can be used to access an
539 object of one of its constrained subtypes, e.g. when a function with an
540 unconstrained parameter passed by reference is called on an object and
541 inlined. But, even in the case of a fixed size, type and subtypes are
542 not equivalent enough as to share the same TYPE_CANONICAL, since this
543 would mean that conversions between them are useless, whereas they are
544 not (e.g. type and subtypes can have different modes). So, in the end,
545 they are only guaranteed to have the same alias set. */
546 if (get_alias_set (type1) == get_alias_set (type2))
549 /* The types are known to be not equal. */
553 /* Determine if the two component references REF1 and REF2 which are
554 based on access types TYPE1 and TYPE2 and of which at least one is based
555 on an indirect reference may alias. REF2 is the only one that can
556 be a decl in which case REF2_IS_DECL is true.
557 REF1_ALIAS_SET, BASE1_ALIAS_SET, REF2_ALIAS_SET and BASE2_ALIAS_SET
558 are the respective alias sets. */
561 aliasing_component_refs_p (tree ref1, tree type1,
562 alias_set_type ref1_alias_set,
563 alias_set_type base1_alias_set,
564 HOST_WIDE_INT offset1, HOST_WIDE_INT max_size1,
565 tree ref2, tree type2,
566 alias_set_type ref2_alias_set,
567 alias_set_type base2_alias_set,
568 HOST_WIDE_INT offset2, HOST_WIDE_INT max_size2,
571 /* If one reference is a component references through pointers try to find a
572 common base and apply offset based disambiguation. This handles
574 struct A { int i; int j; } *q;
575 struct B { struct A a; int k; } *p;
576 disambiguating q->i and p->a.j. */
580 /* Now search for the type1 in the access path of ref2. This
581 would be a common base for doing offset based disambiguation on. */
583 while (handled_component_p (*refp)
584 && same_type_for_tbaa (TREE_TYPE (*refp), type1) == 0)
585 refp = &TREE_OPERAND (*refp, 0);
586 same_p = same_type_for_tbaa (TREE_TYPE (*refp), type1);
587 /* If we couldn't compare types we have to bail out. */
590 else if (same_p == 1)
592 HOST_WIDE_INT offadj, sztmp, msztmp;
593 get_ref_base_and_extent (*refp, &offadj, &sztmp, &msztmp);
595 return ranges_overlap_p (offset1, max_size1, offset2, max_size2);
597 /* If we didn't find a common base, try the other way around. */
599 while (handled_component_p (*refp)
600 && same_type_for_tbaa (TREE_TYPE (*refp), type2) == 0)
601 refp = &TREE_OPERAND (*refp, 0);
602 same_p = same_type_for_tbaa (TREE_TYPE (*refp), type2);
603 /* If we couldn't compare types we have to bail out. */
606 else if (same_p == 1)
608 HOST_WIDE_INT offadj, sztmp, msztmp;
609 get_ref_base_and_extent (*refp, &offadj, &sztmp, &msztmp);
611 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.
616 But we can still have a path that goes B1.path1...B2.path2 with
617 a part that we do not see. So we can only disambiguate now
618 if there is no B2 in the tail of path1 and no B1 on the
620 if (base1_alias_set == ref2_alias_set
621 || alias_set_subset_of (base1_alias_set, ref2_alias_set))
623 /* If this is ptr vs. decl then we know there is no ptr ... decl path. */
625 return (base2_alias_set == ref1_alias_set
626 || alias_set_subset_of (base2_alias_set, ref1_alias_set));
630 /* Return true if two memory references based on the variables BASE1
631 and BASE2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and
632 [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. */
635 decl_refs_may_alias_p (tree base1,
636 HOST_WIDE_INT offset1, HOST_WIDE_INT max_size1,
638 HOST_WIDE_INT offset2, HOST_WIDE_INT max_size2)
640 gcc_assert (SSA_VAR_P (base1) && SSA_VAR_P (base2));
642 /* If both references are based on different variables, they cannot alias. */
646 /* If both references are based on the same variable, they cannot alias if
647 the accesses do not overlap. */
648 return ranges_overlap_p (offset1, max_size1, offset2, max_size2);
651 /* Return true if an indirect reference based on *PTR1 constrained
652 to [OFFSET1, OFFSET1 + MAX_SIZE1) may alias a variable based on BASE2
653 constrained to [OFFSET2, OFFSET2 + MAX_SIZE2). *PTR1 and BASE2 have
654 the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1
655 in which case they are computed on-demand. REF1 and REF2
656 if non-NULL are the complete memory reference trees. */
659 indirect_ref_may_alias_decl_p (tree ref1 ATTRIBUTE_UNUSED, tree base1,
660 HOST_WIDE_INT offset1,
661 HOST_WIDE_INT max_size1 ATTRIBUTE_UNUSED,
662 alias_set_type ref1_alias_set,
663 alias_set_type base1_alias_set,
664 tree ref2 ATTRIBUTE_UNUSED, tree base2,
665 HOST_WIDE_INT offset2, HOST_WIDE_INT max_size2,
666 alias_set_type ref2_alias_set,
667 alias_set_type base2_alias_set, bool tbaa_p)
671 HOST_WIDE_INT offset1p = offset1, offset2p = offset2;
673 ptr1 = TREE_OPERAND (base1, 0);
675 /* The offset embedded in MEM_REFs can be negative. Bias them
676 so that the resulting offset adjustment is positive. */
677 if (TREE_CODE (base1) == MEM_REF
678 || TREE_CODE (base1) == TARGET_MEM_REF)
680 double_int moff = mem_ref_offset (base1);
681 moff = double_int_lshift (moff,
683 ? 3 : exact_log2 (BITS_PER_UNIT),
684 HOST_BITS_PER_DOUBLE_INT, true);
685 if (double_int_negative_p (moff))
686 offset2p += double_int_neg (moff).low;
688 offset1p += moff.low;
691 /* If only one reference is based on a variable, they cannot alias if
692 the pointer access is beyond the extent of the variable access.
693 (the pointer base cannot validly point to an offset less than zero
695 They also cannot alias if the pointer may not point to the decl. */
696 if ((TREE_CODE (base1) != TARGET_MEM_REF || !TMR_INDEX (base1))
697 && !ranges_overlap_p (MAX (0, offset1p), -1, offset2p, max_size2))
699 if (!ptr_deref_may_alias_decl_p (ptr1, base2))
702 /* Disambiguations that rely on strict aliasing rules follow. */
703 if (!flag_strict_aliasing || !tbaa_p)
706 if (TREE_CODE (base1) == MEM_REF)
707 ptrtype1 = TREE_TYPE (TREE_OPERAND (base1, 1));
708 else if (TREE_CODE (base1) == TARGET_MEM_REF)
709 ptrtype1 = TREE_TYPE (TMR_OFFSET (base1));
711 ptrtype1 = TREE_TYPE (ptr1);
713 /* If the alias set for a pointer access is zero all bets are off. */
714 if (base1_alias_set == -1)
715 base1_alias_set = get_deref_alias_set (ptrtype1);
716 if (base1_alias_set == 0)
718 if (base2_alias_set == -1)
719 base2_alias_set = get_alias_set (base2);
721 /* If both references are through the same type, they do not alias
722 if the accesses do not overlap. This does extra disambiguation
723 for mixed/pointer accesses but requires strict aliasing.
724 For MEM_REFs we require that the component-ref offset we computed
725 is relative to the start of the type which we ensure by
726 comparing rvalue and access type and disregarding the constant
728 if ((TREE_CODE (base1) != TARGET_MEM_REF || !TMR_INDEX (base1))
729 && (TREE_CODE (base1) != MEM_REF
730 || same_type_for_tbaa (TREE_TYPE (base1), TREE_TYPE (ptrtype1)) == 1)
731 && same_type_for_tbaa (TREE_TYPE (ptrtype1), TREE_TYPE (base2)) == 1)
732 return ranges_overlap_p (offset1, max_size1, offset2, max_size2);
734 /* When we are trying to disambiguate an access with a pointer dereference
735 as base versus one with a decl as base we can use both the size
736 of the decl and its dynamic type for extra disambiguation.
737 ??? We do not know anything about the dynamic type of the decl
738 other than that its alias-set contains base2_alias_set as a subset
739 which does not help us here. */
740 /* As we know nothing useful about the dynamic type of the decl just
741 use the usual conflict check rather than a subset test.
742 ??? We could introduce -fvery-strict-aliasing when the language
743 does not allow decls to have a dynamic type that differs from their
744 static type. Then we can check
745 !alias_set_subset_of (base1_alias_set, base2_alias_set) instead. */
746 if (base1_alias_set != base2_alias_set
747 && !alias_sets_conflict_p (base1_alias_set, base2_alias_set))
749 /* If the size of the access relevant for TBAA through the pointer
750 is bigger than the size of the decl we can't possibly access the
751 decl via that pointer. */
752 if (DECL_SIZE (base2) && COMPLETE_TYPE_P (TREE_TYPE (ptrtype1))
753 && TREE_CODE (DECL_SIZE (base2)) == INTEGER_CST
754 && TREE_CODE (TYPE_SIZE (TREE_TYPE (ptrtype1))) == INTEGER_CST
755 /* ??? This in turn may run afoul when a decl of type T which is
756 a member of union type U is accessed through a pointer to
757 type U and sizeof T is smaller than sizeof U. */
758 && TREE_CODE (TREE_TYPE (ptrtype1)) != UNION_TYPE
759 && TREE_CODE (TREE_TYPE (ptrtype1)) != QUAL_UNION_TYPE
760 && tree_int_cst_lt (DECL_SIZE (base2), TYPE_SIZE (TREE_TYPE (ptrtype1))))
763 /* Do access-path based disambiguation. */
765 && handled_component_p (ref1)
766 && handled_component_p (ref2)
767 && TREE_CODE (base1) != TARGET_MEM_REF
768 && (TREE_CODE (base1) != MEM_REF
769 || same_type_for_tbaa (TREE_TYPE (base1), TREE_TYPE (ptrtype1)) == 1))
770 return aliasing_component_refs_p (ref1, TREE_TYPE (ptrtype1),
771 ref1_alias_set, base1_alias_set,
773 ref2, TREE_TYPE (base2),
774 ref2_alias_set, base2_alias_set,
775 offset2, max_size2, true);
780 /* Return true if two indirect references based on *PTR1
781 and *PTR2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and
782 [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. *PTR1 and *PTR2 have
783 the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1
784 in which case they are computed on-demand. REF1 and REF2
785 if non-NULL are the complete memory reference trees. */
788 indirect_refs_may_alias_p (tree ref1 ATTRIBUTE_UNUSED, tree base1,
789 HOST_WIDE_INT offset1, HOST_WIDE_INT max_size1,
790 alias_set_type ref1_alias_set,
791 alias_set_type base1_alias_set,
792 tree ref2 ATTRIBUTE_UNUSED, tree base2,
793 HOST_WIDE_INT offset2, HOST_WIDE_INT max_size2,
794 alias_set_type ref2_alias_set,
795 alias_set_type base2_alias_set, bool tbaa_p)
799 tree ptrtype1, ptrtype2;
801 ptr1 = TREE_OPERAND (base1, 0);
802 ptr2 = TREE_OPERAND (base2, 0);
804 /* If both bases are based on pointers they cannot alias if they may not
805 point to the same memory object or if they point to the same object
806 and the accesses do not overlap. */
807 if ((!cfun || gimple_in_ssa_p (cfun))
808 && operand_equal_p (ptr1, ptr2, 0)
809 && (((TREE_CODE (base1) != TARGET_MEM_REF
810 || !TMR_INDEX (base1))
811 && (TREE_CODE (base2) != TARGET_MEM_REF
812 || !TMR_INDEX (base2)))
813 || (TREE_CODE (base1) == TARGET_MEM_REF
814 && TREE_CODE (base2) == TARGET_MEM_REF
815 && (TMR_STEP (base1) == TMR_STEP (base2)
816 || (TMR_STEP (base1) && TMR_STEP (base2)
817 && operand_equal_p (TMR_STEP (base1),
818 TMR_STEP (base2), 0)))
819 && operand_equal_p (TMR_INDEX (base1), TMR_INDEX (base2), 0))))
821 /* The offset embedded in MEM_REFs can be negative. Bias them
822 so that the resulting offset adjustment is positive. */
823 if (TREE_CODE (base1) == MEM_REF
824 || TREE_CODE (base1) == TARGET_MEM_REF)
826 double_int moff = mem_ref_offset (base1);
827 moff = double_int_lshift (moff,
829 ? 3 : exact_log2 (BITS_PER_UNIT),
830 HOST_BITS_PER_DOUBLE_INT, true);
831 if (double_int_negative_p (moff))
832 offset2 += double_int_neg (moff).low;
836 if (TREE_CODE (base2) == MEM_REF
837 || TREE_CODE (base2) == TARGET_MEM_REF)
839 double_int moff = mem_ref_offset (base2);
840 moff = double_int_lshift (moff,
842 ? 3 : exact_log2 (BITS_PER_UNIT),
843 HOST_BITS_PER_DOUBLE_INT, true);
844 if (double_int_negative_p (moff))
845 offset1 += double_int_neg (moff).low;
849 return ranges_overlap_p (offset1, max_size1, offset2, max_size2);
851 if (!ptr_derefs_may_alias_p (ptr1, ptr2))
854 /* Disambiguations that rely on strict aliasing rules follow. */
855 if (!flag_strict_aliasing || !tbaa_p)
858 if (TREE_CODE (base1) == MEM_REF)
859 ptrtype1 = TREE_TYPE (TREE_OPERAND (base1, 1));
860 else if (TREE_CODE (base1) == TARGET_MEM_REF)
861 ptrtype1 = TREE_TYPE (TMR_OFFSET (base1));
863 ptrtype1 = TREE_TYPE (ptr1);
864 if (TREE_CODE (base2) == MEM_REF)
865 ptrtype2 = TREE_TYPE (TREE_OPERAND (base2, 1));
866 else if (TREE_CODE (base2) == TARGET_MEM_REF)
867 ptrtype2 = TREE_TYPE (TMR_OFFSET (base2));
869 ptrtype2 = TREE_TYPE (ptr2);
871 /* If the alias set for a pointer access is zero all bets are off. */
872 if (base1_alias_set == -1)
873 base1_alias_set = get_deref_alias_set (ptrtype1);
874 if (base1_alias_set == 0)
876 if (base2_alias_set == -1)
877 base2_alias_set = get_deref_alias_set (ptrtype2);
878 if (base2_alias_set == 0)
881 /* If both references are through the same type, they do not alias
882 if the accesses do not overlap. This does extra disambiguation
883 for mixed/pointer accesses but requires strict aliasing. */
884 if ((TREE_CODE (base1) != TARGET_MEM_REF || !TMR_INDEX (base1))
885 && (TREE_CODE (base2) != TARGET_MEM_REF || !TMR_INDEX (base2))
886 && (TREE_CODE (base1) != MEM_REF
887 || same_type_for_tbaa (TREE_TYPE (base1), TREE_TYPE (ptrtype1)) == 1)
888 && (TREE_CODE (base2) != MEM_REF
889 || same_type_for_tbaa (TREE_TYPE (base2), TREE_TYPE (ptrtype2)) == 1)
890 && same_type_for_tbaa (TREE_TYPE (ptrtype1),
891 TREE_TYPE (ptrtype2)) == 1)
892 return ranges_overlap_p (offset1, max_size1, offset2, max_size2);
894 /* Do type-based disambiguation. */
895 if (base1_alias_set != base2_alias_set
896 && !alias_sets_conflict_p (base1_alias_set, base2_alias_set))
899 /* Do access-path based disambiguation. */
901 && handled_component_p (ref1)
902 && handled_component_p (ref2)
903 && TREE_CODE (base1) != TARGET_MEM_REF
904 && TREE_CODE (base2) != TARGET_MEM_REF
905 && (TREE_CODE (base1) != MEM_REF
906 || same_type_for_tbaa (TREE_TYPE (base1), TREE_TYPE (ptrtype1)) == 1)
907 && (TREE_CODE (base2) != MEM_REF
908 || same_type_for_tbaa (TREE_TYPE (base2), TREE_TYPE (ptrtype2)) == 1))
909 return aliasing_component_refs_p (ref1, TREE_TYPE (ptrtype1),
910 ref1_alias_set, base1_alias_set,
912 ref2, TREE_TYPE (ptrtype2),
913 ref2_alias_set, base2_alias_set,
914 offset2, max_size2, false);
919 /* Return true, if the two memory references REF1 and REF2 may alias. */
922 refs_may_alias_p_1 (ao_ref *ref1, ao_ref *ref2, bool tbaa_p)
925 HOST_WIDE_INT offset1 = 0, offset2 = 0;
926 HOST_WIDE_INT max_size1 = -1, max_size2 = -1;
927 bool var1_p, var2_p, ind1_p, ind2_p;
929 gcc_checking_assert ((!ref1->ref
930 || TREE_CODE (ref1->ref) == SSA_NAME
931 || DECL_P (ref1->ref)
932 || handled_component_p (ref1->ref)
933 || INDIRECT_REF_P (ref1->ref)
934 || TREE_CODE (ref1->ref) == MEM_REF
935 || TREE_CODE (ref1->ref) == TARGET_MEM_REF)
937 || TREE_CODE (ref2->ref) == SSA_NAME
938 || DECL_P (ref2->ref)
939 || handled_component_p (ref2->ref)
940 || INDIRECT_REF_P (ref2->ref)
941 || TREE_CODE (ref2->ref) == MEM_REF
942 || TREE_CODE (ref2->ref) == TARGET_MEM_REF));
944 /* Decompose the references into their base objects and the access. */
945 base1 = ao_ref_base (ref1);
946 offset1 = ref1->offset;
947 max_size1 = ref1->max_size;
948 base2 = ao_ref_base (ref2);
949 offset2 = ref2->offset;
950 max_size2 = ref2->max_size;
952 /* We can end up with registers or constants as bases for example from
953 *D.1663_44 = VIEW_CONVERT_EXPR<struct DB_LSN>(__tmp$B0F64_59);
954 which is seen as a struct copy. */
955 if (TREE_CODE (base1) == SSA_NAME
956 || TREE_CODE (base2) == SSA_NAME
957 || TREE_CODE (base1) == CONST_DECL
958 || TREE_CODE (base2) == CONST_DECL
959 || is_gimple_min_invariant (base1)
960 || is_gimple_min_invariant (base2))
963 /* We can end up refering to code via function and label decls.
964 As we likely do not properly track code aliases conservatively
966 if (TREE_CODE (base1) == FUNCTION_DECL
967 || TREE_CODE (base2) == FUNCTION_DECL
968 || TREE_CODE (base1) == LABEL_DECL
969 || TREE_CODE (base2) == LABEL_DECL)
972 /* Defer to simple offset based disambiguation if we have
973 references based on two decls. Do this before defering to
974 TBAA to handle must-alias cases in conformance with the
975 GCC extension of allowing type-punning through unions. */
976 var1_p = SSA_VAR_P (base1);
977 var2_p = SSA_VAR_P (base2);
978 if (var1_p && var2_p)
979 return decl_refs_may_alias_p (base1, offset1, max_size1,
980 base2, offset2, max_size2);
982 ind1_p = (INDIRECT_REF_P (base1)
983 || (TREE_CODE (base1) == MEM_REF)
984 || (TREE_CODE (base1) == TARGET_MEM_REF));
985 ind2_p = (INDIRECT_REF_P (base2)
986 || (TREE_CODE (base2) == MEM_REF)
987 || (TREE_CODE (base2) == TARGET_MEM_REF));
989 /* Canonicalize the pointer-vs-decl case. */
990 if (ind1_p && var2_p)
995 tmp1 = offset1; offset1 = offset2; offset2 = tmp1;
996 tmp1 = max_size1; max_size1 = max_size2; max_size2 = tmp1;
997 tmp2 = base1; base1 = base2; base2 = tmp2;
998 tmp3 = ref1; ref1 = ref2; ref2 = tmp3;
1005 /* First defer to TBAA if possible. */
1007 && flag_strict_aliasing
1008 && !alias_sets_conflict_p (ao_ref_alias_set (ref1),
1009 ao_ref_alias_set (ref2)))
1012 /* Dispatch to the pointer-vs-decl or pointer-vs-pointer disambiguators. */
1013 if (var1_p && ind2_p)
1014 return indirect_ref_may_alias_decl_p (ref2->ref, base2,
1016 ao_ref_alias_set (ref2), -1,
1019 ao_ref_alias_set (ref1),
1020 ao_ref_base_alias_set (ref1),
1022 else if (ind1_p && ind2_p)
1023 return indirect_refs_may_alias_p (ref1->ref, base1,
1025 ao_ref_alias_set (ref1), -1,
1028 ao_ref_alias_set (ref2), -1,
1035 refs_may_alias_p (tree ref1, tree ref2)
1039 ao_ref_init (&r1, ref1);
1040 ao_ref_init (&r2, ref2);
1041 res = refs_may_alias_p_1 (&r1, &r2, true);
1043 ++alias_stats.refs_may_alias_p_may_alias;
1045 ++alias_stats.refs_may_alias_p_no_alias;
1049 /* Returns true if there is a anti-dependence for the STORE that
1050 executes after the LOAD. */
1053 refs_anti_dependent_p (tree load, tree store)
1056 ao_ref_init (&r1, load);
1057 ao_ref_init (&r2, store);
1058 return refs_may_alias_p_1 (&r1, &r2, false);
1061 /* Returns true if there is a output dependence for the stores
1062 STORE1 and STORE2. */
1065 refs_output_dependent_p (tree store1, tree store2)
1068 ao_ref_init (&r1, store1);
1069 ao_ref_init (&r2, store2);
1070 return refs_may_alias_p_1 (&r1, &r2, false);
1073 /* If the call CALL may use the memory reference REF return true,
1074 otherwise return false. */
1077 ref_maybe_used_by_call_p_1 (gimple call, ao_ref *ref)
1081 int flags = gimple_call_flags (call);
1083 /* Const functions without a static chain do not implicitly use memory. */
1084 if (!gimple_call_chain (call)
1085 && (flags & (ECF_CONST|ECF_NOVOPS)))
1088 base = ao_ref_base (ref);
1092 /* If the reference is based on a decl that is not aliased the call
1093 cannot possibly use it. */
1095 && !may_be_aliased (base)
1096 /* But local statics can be used through recursion. */
1097 && !is_global_var (base))
1100 callee = gimple_call_fndecl (call);
1102 /* Handle those builtin functions explicitly that do not act as
1103 escape points. See tree-ssa-structalias.c:find_func_aliases
1104 for the list of builtins we might need to handle here. */
1105 if (callee != NULL_TREE
1106 && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL)
1107 switch (DECL_FUNCTION_CODE (callee))
1109 /* All the following functions clobber memory pointed to by
1110 their first argument. */
1111 case BUILT_IN_STRCPY:
1112 case BUILT_IN_STRNCPY:
1113 case BUILT_IN_MEMCPY:
1114 case BUILT_IN_MEMMOVE:
1115 case BUILT_IN_MEMPCPY:
1116 case BUILT_IN_STPCPY:
1117 case BUILT_IN_STPNCPY:
1118 case BUILT_IN_STRCAT:
1119 case BUILT_IN_STRNCAT:
1122 tree size = NULL_TREE;
1123 if (gimple_call_num_args (call) == 3)
1124 size = gimple_call_arg (call, 2);
1125 ao_ref_init_from_ptr_and_size (&dref,
1126 gimple_call_arg (call, 1),
1128 return refs_may_alias_p_1 (&dref, ref, false);
1130 case BUILT_IN_BCOPY:
1133 tree size = gimple_call_arg (call, 2);
1134 ao_ref_init_from_ptr_and_size (&dref,
1135 gimple_call_arg (call, 0),
1137 return refs_may_alias_p_1 (&dref, ref, false);
1139 /* The following builtins do not read from memory. */
1141 case BUILT_IN_MALLOC:
1142 case BUILT_IN_CALLOC:
1143 case BUILT_IN_MEMSET:
1144 case BUILT_IN_FREXP:
1145 case BUILT_IN_FREXPF:
1146 case BUILT_IN_FREXPL:
1147 case BUILT_IN_GAMMA_R:
1148 case BUILT_IN_GAMMAF_R:
1149 case BUILT_IN_GAMMAL_R:
1150 case BUILT_IN_LGAMMA_R:
1151 case BUILT_IN_LGAMMAF_R:
1152 case BUILT_IN_LGAMMAL_R:
1154 case BUILT_IN_MODFF:
1155 case BUILT_IN_MODFL:
1156 case BUILT_IN_REMQUO:
1157 case BUILT_IN_REMQUOF:
1158 case BUILT_IN_REMQUOL:
1159 case BUILT_IN_SINCOS:
1160 case BUILT_IN_SINCOSF:
1161 case BUILT_IN_SINCOSL:
1165 /* Fallthru to general call handling. */;
1168 /* Check if base is a global static variable that is not read
1170 if (TREE_CODE (base) == VAR_DECL
1171 && TREE_STATIC (base))
1175 if (callee != NULL_TREE
1177 = ipa_reference_get_not_read_global (cgraph_node (callee)))
1178 && bitmap_bit_p (not_read, DECL_UID (base)))
1182 /* Check if the base variable is call-used. */
1185 if (pt_solution_includes (gimple_call_use_set (call), base))
1188 else if ((INDIRECT_REF_P (base)
1189 || TREE_CODE (base) == MEM_REF)
1190 && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME)
1192 struct ptr_info_def *pi = SSA_NAME_PTR_INFO (TREE_OPERAND (base, 0));
1196 if (pt_solutions_intersect (gimple_call_use_set (call), &pi->pt))
1202 /* Inspect call arguments for passed-by-value aliases. */
1204 for (i = 0; i < gimple_call_num_args (call); ++i)
1206 tree op = gimple_call_arg (call, i);
1207 int flags = gimple_call_arg_flags (call, i);
1209 if (flags & EAF_UNUSED)
1212 if (TREE_CODE (op) == WITH_SIZE_EXPR)
1213 op = TREE_OPERAND (op, 0);
1215 if (TREE_CODE (op) != SSA_NAME
1216 && !is_gimple_min_invariant (op))
1219 ao_ref_init (&r, op);
1220 if (refs_may_alias_p_1 (&r, ref, true))
1229 ref_maybe_used_by_call_p (gimple call, tree ref)
1233 ao_ref_init (&r, ref);
1234 res = ref_maybe_used_by_call_p_1 (call, &r);
1236 ++alias_stats.ref_maybe_used_by_call_p_may_alias;
1238 ++alias_stats.ref_maybe_used_by_call_p_no_alias;
1243 /* If the statement STMT may use the memory reference REF return
1244 true, otherwise return false. */
1247 ref_maybe_used_by_stmt_p (gimple stmt, tree ref)
1249 if (is_gimple_assign (stmt))
1253 /* All memory assign statements are single. */
1254 if (!gimple_assign_single_p (stmt))
1257 rhs = gimple_assign_rhs1 (stmt);
1258 if (is_gimple_reg (rhs)
1259 || is_gimple_min_invariant (rhs)
1260 || gimple_assign_rhs_code (stmt) == CONSTRUCTOR)
1263 return refs_may_alias_p (rhs, ref);
1265 else if (is_gimple_call (stmt))
1266 return ref_maybe_used_by_call_p (stmt, ref);
1271 /* If the call in statement CALL may clobber the memory reference REF
1272 return true, otherwise return false. */
1275 call_may_clobber_ref_p_1 (gimple call, ao_ref *ref)
1280 /* If the call is pure or const it cannot clobber anything. */
1281 if (gimple_call_flags (call)
1282 & (ECF_PURE|ECF_CONST|ECF_LOOPING_CONST_OR_PURE|ECF_NOVOPS))
1285 base = ao_ref_base (ref);
1289 if (TREE_CODE (base) == SSA_NAME
1290 || CONSTANT_CLASS_P (base))
1293 /* If the reference is based on a decl that is not aliased the call
1294 cannot possibly clobber it. */
1296 && !may_be_aliased (base)
1297 /* But local non-readonly statics can be modified through recursion
1298 or the call may implement a threading barrier which we must
1299 treat as may-def. */
1300 && (TREE_READONLY (base)
1301 || !is_global_var (base)))
1304 callee = gimple_call_fndecl (call);
1306 /* Handle those builtin functions explicitly that do not act as
1307 escape points. See tree-ssa-structalias.c:find_func_aliases
1308 for the list of builtins we might need to handle here. */
1309 if (callee != NULL_TREE
1310 && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL)
1311 switch (DECL_FUNCTION_CODE (callee))
1313 /* All the following functions clobber memory pointed to by
1314 their first argument. */
1315 case BUILT_IN_STRCPY:
1316 case BUILT_IN_STRNCPY:
1317 case BUILT_IN_MEMCPY:
1318 case BUILT_IN_MEMMOVE:
1319 case BUILT_IN_MEMPCPY:
1320 case BUILT_IN_STPCPY:
1321 case BUILT_IN_STPNCPY:
1322 case BUILT_IN_STRCAT:
1323 case BUILT_IN_STRNCAT:
1324 case BUILT_IN_MEMSET:
1327 tree size = NULL_TREE;
1328 if (gimple_call_num_args (call) == 3)
1329 size = gimple_call_arg (call, 2);
1330 ao_ref_init_from_ptr_and_size (&dref,
1331 gimple_call_arg (call, 0),
1333 return refs_may_alias_p_1 (&dref, ref, false);
1335 case BUILT_IN_BCOPY:
1338 tree size = gimple_call_arg (call, 2);
1339 ao_ref_init_from_ptr_and_size (&dref,
1340 gimple_call_arg (call, 1),
1342 return refs_may_alias_p_1 (&dref, ref, false);
1344 /* Allocating memory does not have any side-effects apart from
1345 being the definition point for the pointer. */
1346 case BUILT_IN_MALLOC:
1347 case BUILT_IN_CALLOC:
1348 /* Unix98 specifies that errno is set on allocation failure.
1349 Until we properly can track the errno location assume it
1350 is not a local decl but external or anonymous storage in
1351 a different translation unit. Also assume it is of
1352 type int as required by the standard. */
1354 && TREE_TYPE (base) == integer_type_node)
1356 struct ptr_info_def *pi;
1358 && !TREE_STATIC (base))
1360 else if ((INDIRECT_REF_P (base)
1361 || TREE_CODE (base) == MEM_REF)
1362 && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME
1363 && (pi = SSA_NAME_PTR_INFO (TREE_OPERAND (base, 0))))
1364 return pi->pt.anything || pi->pt.nonlocal;
1367 /* Freeing memory kills the pointed-to memory. More importantly
1368 the call has to serve as a barrier for moving loads and stores
1372 tree ptr = gimple_call_arg (call, 0);
1373 return ptr_deref_may_alias_ref_p_1 (ptr, ref);
1375 case BUILT_IN_GAMMA_R:
1376 case BUILT_IN_GAMMAF_R:
1377 case BUILT_IN_GAMMAL_R:
1378 case BUILT_IN_LGAMMA_R:
1379 case BUILT_IN_LGAMMAF_R:
1380 case BUILT_IN_LGAMMAL_R:
1382 tree out = gimple_call_arg (call, 1);
1383 if (ptr_deref_may_alias_ref_p_1 (out, ref))
1385 if (flag_errno_math)
1389 case BUILT_IN_FREXP:
1390 case BUILT_IN_FREXPF:
1391 case BUILT_IN_FREXPL:
1393 case BUILT_IN_MODFF:
1394 case BUILT_IN_MODFL:
1396 tree out = gimple_call_arg (call, 1);
1397 return ptr_deref_may_alias_ref_p_1 (out, ref);
1399 case BUILT_IN_REMQUO:
1400 case BUILT_IN_REMQUOF:
1401 case BUILT_IN_REMQUOL:
1403 tree out = gimple_call_arg (call, 2);
1404 if (ptr_deref_may_alias_ref_p_1 (out, ref))
1406 if (flag_errno_math)
1410 case BUILT_IN_SINCOS:
1411 case BUILT_IN_SINCOSF:
1412 case BUILT_IN_SINCOSL:
1414 tree sin = gimple_call_arg (call, 1);
1415 tree cos = gimple_call_arg (call, 2);
1416 return (ptr_deref_may_alias_ref_p_1 (sin, ref)
1417 || ptr_deref_may_alias_ref_p_1 (cos, ref));
1420 /* Fallthru to general call handling. */;
1423 /* Check if base is a global static variable that is not written
1425 if (callee != NULL_TREE
1426 && TREE_CODE (base) == VAR_DECL
1427 && TREE_STATIC (base))
1432 = ipa_reference_get_not_written_global (cgraph_node (callee)))
1433 && bitmap_bit_p (not_written, DECL_UID (base)))
1437 /* Check if the base variable is call-clobbered. */
1439 return pt_solution_includes (gimple_call_clobber_set (call), base);
1440 else if ((INDIRECT_REF_P (base)
1441 || TREE_CODE (base) == MEM_REF)
1442 && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME)
1444 struct ptr_info_def *pi = SSA_NAME_PTR_INFO (TREE_OPERAND (base, 0));
1448 return pt_solutions_intersect (gimple_call_clobber_set (call), &pi->pt);
1454 /* If the call in statement CALL may clobber the memory reference REF
1455 return true, otherwise return false. */
1458 call_may_clobber_ref_p (gimple call, tree ref)
1462 ao_ref_init (&r, ref);
1463 res = call_may_clobber_ref_p_1 (call, &r);
1465 ++alias_stats.call_may_clobber_ref_p_may_alias;
1467 ++alias_stats.call_may_clobber_ref_p_no_alias;
1472 /* If the statement STMT may clobber the memory reference REF return true,
1473 otherwise return false. */
1476 stmt_may_clobber_ref_p_1 (gimple stmt, ao_ref *ref)
1478 if (is_gimple_call (stmt))
1480 tree lhs = gimple_call_lhs (stmt);
1482 && !is_gimple_reg (lhs))
1485 ao_ref_init (&r, lhs);
1486 if (refs_may_alias_p_1 (ref, &r, true))
1490 return call_may_clobber_ref_p_1 (stmt, ref);
1492 else if (gimple_assign_single_p (stmt))
1494 tree lhs = gimple_assign_lhs (stmt);
1495 if (!is_gimple_reg (lhs))
1498 ao_ref_init (&r, gimple_assign_lhs (stmt));
1499 return refs_may_alias_p_1 (ref, &r, true);
1502 else if (gimple_code (stmt) == GIMPLE_ASM)
1509 stmt_may_clobber_ref_p (gimple stmt, tree ref)
1512 ao_ref_init (&r, ref);
1513 return stmt_may_clobber_ref_p_1 (stmt, &r);
1517 /* Walk the virtual use-def chain of VUSE until hitting the virtual operand
1518 TARGET or a statement clobbering the memory reference REF in which
1519 case false is returned. The walk starts with VUSE, one argument of PHI. */
1522 maybe_skip_until (gimple phi, tree target, ao_ref *ref,
1523 tree vuse, bitmap *visited)
1526 *visited = BITMAP_ALLOC (NULL);
1528 bitmap_set_bit (*visited, SSA_NAME_VERSION (PHI_RESULT (phi)));
1530 /* Walk until we hit the target. */
1531 while (vuse != target)
1533 gimple def_stmt = SSA_NAME_DEF_STMT (vuse);
1534 /* Recurse for PHI nodes. */
1535 if (gimple_code (def_stmt) == GIMPLE_PHI)
1537 /* An already visited PHI node ends the walk successfully. */
1538 if (bitmap_bit_p (*visited, SSA_NAME_VERSION (PHI_RESULT (def_stmt))))
1540 vuse = get_continuation_for_phi (def_stmt, ref, visited);
1545 /* A clobbering statement or the end of the IL ends it failing. */
1546 else if (gimple_nop_p (def_stmt)
1547 || stmt_may_clobber_ref_p_1 (def_stmt, ref))
1549 vuse = gimple_vuse (def_stmt);
1554 /* Starting from a PHI node for the virtual operand of the memory reference
1555 REF find a continuation virtual operand that allows to continue walking
1556 statements dominating PHI skipping only statements that cannot possibly
1557 clobber REF. Returns NULL_TREE if no suitable virtual operand can
1561 get_continuation_for_phi (gimple phi, ao_ref *ref, bitmap *visited)
1563 unsigned nargs = gimple_phi_num_args (phi);
1565 /* Through a single-argument PHI we can simply look through. */
1567 return PHI_ARG_DEF (phi, 0);
1569 /* For two arguments try to skip non-aliasing code until we hit
1570 the phi argument definition that dominates the other one. */
1573 tree arg0 = PHI_ARG_DEF (phi, 0);
1574 tree arg1 = PHI_ARG_DEF (phi, 1);
1575 gimple def0 = SSA_NAME_DEF_STMT (arg0);
1576 gimple def1 = SSA_NAME_DEF_STMT (arg1);
1581 else if (gimple_nop_p (def0)
1582 || (!gimple_nop_p (def1)
1583 && dominated_by_p (CDI_DOMINATORS,
1584 gimple_bb (def1), gimple_bb (def0))))
1586 if (maybe_skip_until (phi, arg0, ref, arg1, visited))
1589 else if (gimple_nop_p (def1)
1590 || dominated_by_p (CDI_DOMINATORS,
1591 gimple_bb (def0), gimple_bb (def1)))
1593 if (maybe_skip_until (phi, arg1, ref, arg0, visited))
1596 /* Special case of a diamond:
1598 goto (cond) ? L1 : L2
1599 L1: store1 = ... #MEM_2 = vuse(MEM_1)
1601 L2: store2 = ... #MEM_3 = vuse(MEM_1)
1602 L3: MEM_4 = PHI<MEM_2, MEM_3>
1603 We were called with the PHI at L3, MEM_2 and MEM_3 don't
1604 dominate each other, but still we can easily skip this PHI node
1605 if we recognize that the vuse MEM operand is the same for both,
1606 and that we can skip both statements (they don't clobber us).
1607 This is still linear. Don't use maybe_skip_until, that might
1608 potentially be slow. */
1609 else if ((common_vuse = gimple_vuse (def0))
1610 && common_vuse == gimple_vuse (def1))
1612 if (!stmt_may_clobber_ref_p_1 (def0, ref)
1613 && !stmt_may_clobber_ref_p_1 (def1, ref))
1621 /* Based on the memory reference REF and its virtual use VUSE call
1622 WALKER for each virtual use that is equivalent to VUSE, including VUSE
1623 itself. That is, for each virtual use for which its defining statement
1624 does not clobber REF.
1626 WALKER is called with REF, the current virtual use and DATA. If
1627 WALKER returns non-NULL the walk stops and its result is returned.
1628 At the end of a non-successful walk NULL is returned.
1630 TRANSLATE if non-NULL is called with a pointer to REF, the virtual
1631 use which definition is a statement that may clobber REF and DATA.
1632 If TRANSLATE returns (void *)-1 the walk stops and NULL is returned.
1633 If TRANSLATE returns non-NULL the walk stops and its result is returned.
1634 If TRANSLATE returns NULL the walk continues and TRANSLATE is supposed
1635 to adjust REF and *DATA to make that valid.
1637 TODO: Cache the vector of equivalent vuses per ref, vuse pair. */
1640 walk_non_aliased_vuses (ao_ref *ref, tree vuse,
1641 void *(*walker)(ao_ref *, tree, void *),
1642 void *(*translate)(ao_ref *, tree, void *), void *data)
1644 bitmap visited = NULL;
1647 timevar_push (TV_ALIAS_STMT_WALK);
1653 /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */
1654 res = (*walker) (ref, vuse, data);
1658 def_stmt = SSA_NAME_DEF_STMT (vuse);
1659 if (gimple_nop_p (def_stmt))
1661 else if (gimple_code (def_stmt) == GIMPLE_PHI)
1662 vuse = get_continuation_for_phi (def_stmt, ref, &visited);
1665 if (stmt_may_clobber_ref_p_1 (def_stmt, ref))
1669 res = (*translate) (ref, vuse, data);
1670 /* Failed lookup and translation. */
1671 if (res == (void *)-1)
1676 /* Lookup succeeded. */
1677 else if (res != NULL)
1679 /* Translation succeeded, continue walking. */
1681 vuse = gimple_vuse (def_stmt);
1687 BITMAP_FREE (visited);
1689 timevar_pop (TV_ALIAS_STMT_WALK);
1695 /* Based on the memory reference REF call WALKER for each vdef which
1696 defining statement may clobber REF, starting with VDEF. If REF
1697 is NULL_TREE, each defining statement is visited.
1699 WALKER is called with REF, the current vdef and DATA. If WALKER
1700 returns true the walk is stopped, otherwise it continues.
1702 At PHI nodes walk_aliased_vdefs forks into one walk for reach
1703 PHI argument (but only one walk continues on merge points), the
1704 return value is true if any of the walks was successful.
1706 The function returns the number of statements walked. */
1709 walk_aliased_vdefs_1 (ao_ref *ref, tree vdef,
1710 bool (*walker)(ao_ref *, tree, void *), void *data,
1711 bitmap *visited, unsigned int cnt)
1715 gimple def_stmt = SSA_NAME_DEF_STMT (vdef);
1718 && !bitmap_set_bit (*visited, SSA_NAME_VERSION (vdef)))
1721 if (gimple_nop_p (def_stmt))
1723 else if (gimple_code (def_stmt) == GIMPLE_PHI)
1727 *visited = BITMAP_ALLOC (NULL);
1728 for (i = 0; i < gimple_phi_num_args (def_stmt); ++i)
1729 cnt += walk_aliased_vdefs_1 (ref, gimple_phi_arg_def (def_stmt, i),
1730 walker, data, visited, 0);
1734 /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */
1737 || stmt_may_clobber_ref_p_1 (def_stmt, ref))
1738 && (*walker) (ref, vdef, data))
1741 vdef = gimple_vuse (def_stmt);
1747 walk_aliased_vdefs (ao_ref *ref, tree vdef,
1748 bool (*walker)(ao_ref *, tree, void *), void *data,
1751 bitmap local_visited = NULL;
1754 timevar_push (TV_ALIAS_STMT_WALK);
1756 ret = walk_aliased_vdefs_1 (ref, vdef, walker, data,
1757 visited ? visited : &local_visited, 0);
1759 BITMAP_FREE (local_visited);
1761 timevar_pop (TV_ALIAS_STMT_WALK);