1 /* Alias analysis for trees.
2 Copyright (C) 2004-2015 Free Software Foundation, Inc.
3 Contributed by Diego Novillo <dnovillo@redhat.com>
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3, or (at your option)
12 GCC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
23 #include "coretypes.h"
30 #include "fold-const.h"
34 #include "dominance.h"
35 #include "timevar.h" /* for TV_ALIAS_STMT_WALK */
36 #include "langhooks.h"
38 #include "tree-pretty-print.h"
40 #include "internal-fn.h"
42 #include "insn-config.h"
52 #include "tree-inline.h"
54 #include "alloc-pool.h"
56 #include "ipa-reference.h"
58 /* Broad overview of how alias analysis on gimple works:
60 Statements clobbering or using memory are linked through the
61 virtual operand factored use-def chain. The virtual operand
62 is unique per function, its symbol is accessible via gimple_vop (cfun).
63 Virtual operands are used for efficiently walking memory statements
64 in the gimple IL and are useful for things like value-numbering as
65 a generation count for memory references.
67 SSA_NAME pointers may have associated points-to information
68 accessible via the SSA_NAME_PTR_INFO macro. Flow-insensitive
69 points-to information is (re-)computed by the TODO_rebuild_alias
70 pass manager todo. Points-to information is also used for more
71 precise tracking of call-clobbered and call-used variables and
72 related disambiguations.
74 This file contains functions for disambiguating memory references,
75 the so called alias-oracle and tools for walking of the gimple IL.
77 The main alias-oracle entry-points are
79 bool stmt_may_clobber_ref_p (gimple *, tree)
81 This function queries if a statement may invalidate (parts of)
82 the memory designated by the reference tree argument.
84 bool ref_maybe_used_by_stmt_p (gimple *, tree)
86 This function queries if a statement may need (parts of) the
87 memory designated by the reference tree argument.
89 There are variants of these functions that only handle the call
90 part of a statement, call_may_clobber_ref_p and ref_maybe_used_by_call_p.
91 Note that these do not disambiguate against a possible call lhs.
93 bool refs_may_alias_p (tree, tree)
95 This function tries to disambiguate two reference trees.
97 bool ptr_deref_may_alias_global_p (tree)
99 This function queries if dereferencing a pointer variable may
102 More low-level disambiguators are available and documented in
103 this file. Low-level disambiguators dealing with points-to
104 information are in tree-ssa-structalias.c. */
107 /* Query statistics for the different low-level disambiguators.
108 A high-level query may trigger multiple of them. */
111 unsigned HOST_WIDE_INT refs_may_alias_p_may_alias;
112 unsigned HOST_WIDE_INT refs_may_alias_p_no_alias;
113 unsigned HOST_WIDE_INT ref_maybe_used_by_call_p_may_alias;
114 unsigned HOST_WIDE_INT ref_maybe_used_by_call_p_no_alias;
115 unsigned HOST_WIDE_INT call_may_clobber_ref_p_may_alias;
116 unsigned HOST_WIDE_INT call_may_clobber_ref_p_no_alias;
120 dump_alias_stats (FILE *s)
122 fprintf (s, "\nAlias oracle query stats:\n");
123 fprintf (s, " refs_may_alias_p: "
124 HOST_WIDE_INT_PRINT_DEC" disambiguations, "
125 HOST_WIDE_INT_PRINT_DEC" queries\n",
126 alias_stats.refs_may_alias_p_no_alias,
127 alias_stats.refs_may_alias_p_no_alias
128 + alias_stats.refs_may_alias_p_may_alias);
129 fprintf (s, " ref_maybe_used_by_call_p: "
130 HOST_WIDE_INT_PRINT_DEC" disambiguations, "
131 HOST_WIDE_INT_PRINT_DEC" queries\n",
132 alias_stats.ref_maybe_used_by_call_p_no_alias,
133 alias_stats.refs_may_alias_p_no_alias
134 + alias_stats.ref_maybe_used_by_call_p_may_alias);
135 fprintf (s, " call_may_clobber_ref_p: "
136 HOST_WIDE_INT_PRINT_DEC" disambiguations, "
137 HOST_WIDE_INT_PRINT_DEC" queries\n",
138 alias_stats.call_may_clobber_ref_p_no_alias,
139 alias_stats.call_may_clobber_ref_p_no_alias
140 + alias_stats.call_may_clobber_ref_p_may_alias);
141 dump_alias_stats_in_alias_c (s);
145 /* Return true, if dereferencing PTR may alias with a global variable. */
148 ptr_deref_may_alias_global_p (tree ptr)
150 struct ptr_info_def *pi;
152 /* If we end up with a pointer constant here that may point
154 if (TREE_CODE (ptr) != SSA_NAME)
157 pi = SSA_NAME_PTR_INFO (ptr);
159 /* If we do not have points-to information for this variable,
164 /* ??? This does not use TBAA to prune globals ptr may not access. */
165 return pt_solution_includes_global (&pi->pt);
168 /* Return true if dereferencing PTR may alias DECL.
169 The caller is responsible for applying TBAA to see if PTR
170 may access DECL at all. */
173 ptr_deref_may_alias_decl_p (tree ptr, tree decl)
175 struct ptr_info_def *pi;
177 /* Conversions are irrelevant for points-to information and
178 data-dependence analysis can feed us those. */
181 /* Anything we do not explicilty handle aliases. */
182 if ((TREE_CODE (ptr) != SSA_NAME
183 && TREE_CODE (ptr) != ADDR_EXPR
184 && TREE_CODE (ptr) != POINTER_PLUS_EXPR)
185 || !POINTER_TYPE_P (TREE_TYPE (ptr))
186 || (TREE_CODE (decl) != VAR_DECL
187 && TREE_CODE (decl) != PARM_DECL
188 && TREE_CODE (decl) != RESULT_DECL))
191 /* Disregard pointer offsetting. */
192 if (TREE_CODE (ptr) == POINTER_PLUS_EXPR)
196 ptr = TREE_OPERAND (ptr, 0);
198 while (TREE_CODE (ptr) == POINTER_PLUS_EXPR);
199 return ptr_deref_may_alias_decl_p (ptr, decl);
202 /* ADDR_EXPR pointers either just offset another pointer or directly
203 specify the pointed-to set. */
204 if (TREE_CODE (ptr) == ADDR_EXPR)
206 tree base = get_base_address (TREE_OPERAND (ptr, 0));
208 && (TREE_CODE (base) == MEM_REF
209 || TREE_CODE (base) == TARGET_MEM_REF))
210 ptr = TREE_OPERAND (base, 0);
215 && CONSTANT_CLASS_P (base))
221 /* Non-aliased variables can not be pointed to. */
222 if (!may_be_aliased (decl))
225 /* If we do not have useful points-to information for this pointer
226 we cannot disambiguate anything else. */
227 pi = SSA_NAME_PTR_INFO (ptr);
231 return pt_solution_includes (&pi->pt, decl);
234 /* Return true if dereferenced PTR1 and PTR2 may alias.
235 The caller is responsible for applying TBAA to see if accesses
236 through PTR1 and PTR2 may conflict at all. */
239 ptr_derefs_may_alias_p (tree ptr1, tree ptr2)
241 struct ptr_info_def *pi1, *pi2;
243 /* Conversions are irrelevant for points-to information and
244 data-dependence analysis can feed us those. */
248 /* Disregard pointer offsetting. */
249 if (TREE_CODE (ptr1) == POINTER_PLUS_EXPR)
253 ptr1 = TREE_OPERAND (ptr1, 0);
255 while (TREE_CODE (ptr1) == POINTER_PLUS_EXPR);
256 return ptr_derefs_may_alias_p (ptr1, ptr2);
258 if (TREE_CODE (ptr2) == POINTER_PLUS_EXPR)
262 ptr2 = TREE_OPERAND (ptr2, 0);
264 while (TREE_CODE (ptr2) == POINTER_PLUS_EXPR);
265 return ptr_derefs_may_alias_p (ptr1, ptr2);
268 /* ADDR_EXPR pointers either just offset another pointer or directly
269 specify the pointed-to set. */
270 if (TREE_CODE (ptr1) == ADDR_EXPR)
272 tree base = get_base_address (TREE_OPERAND (ptr1, 0));
274 && (TREE_CODE (base) == MEM_REF
275 || TREE_CODE (base) == TARGET_MEM_REF))
276 return ptr_derefs_may_alias_p (TREE_OPERAND (base, 0), ptr2);
279 return ptr_deref_may_alias_decl_p (ptr2, base);
283 if (TREE_CODE (ptr2) == ADDR_EXPR)
285 tree base = get_base_address (TREE_OPERAND (ptr2, 0));
287 && (TREE_CODE (base) == MEM_REF
288 || TREE_CODE (base) == TARGET_MEM_REF))
289 return ptr_derefs_may_alias_p (ptr1, TREE_OPERAND (base, 0));
292 return ptr_deref_may_alias_decl_p (ptr1, base);
297 /* From here we require SSA name pointers. Anything else aliases. */
298 if (TREE_CODE (ptr1) != SSA_NAME
299 || TREE_CODE (ptr2) != SSA_NAME
300 || !POINTER_TYPE_P (TREE_TYPE (ptr1))
301 || !POINTER_TYPE_P (TREE_TYPE (ptr2)))
304 /* We may end up with two empty points-to solutions for two same pointers.
305 In this case we still want to say both pointers alias, so shortcut
310 /* If we do not have useful points-to information for either pointer
311 we cannot disambiguate anything else. */
312 pi1 = SSA_NAME_PTR_INFO (ptr1);
313 pi2 = SSA_NAME_PTR_INFO (ptr2);
317 /* ??? This does not use TBAA to prune decls from the intersection
318 that not both pointers may access. */
319 return pt_solutions_intersect (&pi1->pt, &pi2->pt);
322 /* Return true if dereferencing PTR may alias *REF.
323 The caller is responsible for applying TBAA to see if PTR
324 may access *REF at all. */
327 ptr_deref_may_alias_ref_p_1 (tree ptr, ao_ref *ref)
329 tree base = ao_ref_base (ref);
331 if (TREE_CODE (base) == MEM_REF
332 || TREE_CODE (base) == TARGET_MEM_REF)
333 return ptr_derefs_may_alias_p (ptr, TREE_OPERAND (base, 0));
334 else if (DECL_P (base))
335 return ptr_deref_may_alias_decl_p (ptr, base);
340 /* Returns whether reference REF to BASE may refer to global memory. */
343 ref_may_alias_global_p_1 (tree base)
346 return is_global_var (base);
347 else if (TREE_CODE (base) == MEM_REF
348 || TREE_CODE (base) == TARGET_MEM_REF)
349 return ptr_deref_may_alias_global_p (TREE_OPERAND (base, 0));
354 ref_may_alias_global_p (ao_ref *ref)
356 tree base = ao_ref_base (ref);
357 return ref_may_alias_global_p_1 (base);
361 ref_may_alias_global_p (tree ref)
363 tree base = get_base_address (ref);
364 return ref_may_alias_global_p_1 (base);
367 /* Return true whether STMT may clobber global memory. */
370 stmt_may_clobber_global_p (gimple *stmt)
374 if (!gimple_vdef (stmt))
377 /* ??? We can ask the oracle whether an artificial pointer
378 dereference with a pointer with points-to information covering
379 all global memory (what about non-address taken memory?) maybe
380 clobbered by this call. As there is at the moment no convenient
381 way of doing that without generating garbage do some manual
383 ??? We could make a NULL ao_ref argument to the various
384 predicates special, meaning any global memory. */
386 switch (gimple_code (stmt))
389 lhs = gimple_assign_lhs (stmt);
390 return (TREE_CODE (lhs) != SSA_NAME
391 && ref_may_alias_global_p (lhs));
400 /* Dump alias information on FILE. */
403 dump_alias_info (FILE *file)
407 = lang_hooks.decl_printable_name (current_function_decl, 2);
410 fprintf (file, "\n\nAlias information for %s\n\n", funcname);
412 fprintf (file, "Aliased symbols\n\n");
414 FOR_EACH_LOCAL_DECL (cfun, i, var)
416 if (may_be_aliased (var))
417 dump_variable (file, var);
420 fprintf (file, "\nCall clobber information\n");
422 fprintf (file, "\nESCAPED");
423 dump_points_to_solution (file, &cfun->gimple_df->escaped);
425 fprintf (file, "\n\nFlow-insensitive points-to information\n\n");
427 for (i = 1; i < num_ssa_names; i++)
429 tree ptr = ssa_name (i);
430 struct ptr_info_def *pi;
433 || !POINTER_TYPE_P (TREE_TYPE (ptr))
434 || SSA_NAME_IN_FREE_LIST (ptr))
437 pi = SSA_NAME_PTR_INFO (ptr);
439 dump_points_to_info_for (file, ptr);
442 fprintf (file, "\n");
446 /* Dump alias information on stderr. */
449 debug_alias_info (void)
451 dump_alias_info (stderr);
455 /* Dump the points-to set *PT into FILE. */
458 dump_points_to_solution (FILE *file, struct pt_solution *pt)
461 fprintf (file, ", points-to anything");
464 fprintf (file, ", points-to non-local");
467 fprintf (file, ", points-to escaped");
470 fprintf (file, ", points-to unit escaped");
473 fprintf (file, ", points-to NULL");
477 fprintf (file, ", points-to vars: ");
478 dump_decl_set (file, pt->vars);
479 if (pt->vars_contains_nonlocal
480 && pt->vars_contains_escaped_heap)
481 fprintf (file, " (nonlocal, escaped heap)");
482 else if (pt->vars_contains_nonlocal
483 && pt->vars_contains_escaped)
484 fprintf (file, " (nonlocal, escaped)");
485 else if (pt->vars_contains_nonlocal)
486 fprintf (file, " (nonlocal)");
487 else if (pt->vars_contains_escaped_heap)
488 fprintf (file, " (escaped heap)");
489 else if (pt->vars_contains_escaped)
490 fprintf (file, " (escaped)");
495 /* Unified dump function for pt_solution. */
498 debug (pt_solution &ref)
500 dump_points_to_solution (stderr, &ref);
504 debug (pt_solution *ptr)
509 fprintf (stderr, "<nil>\n");
513 /* Dump points-to information for SSA_NAME PTR into FILE. */
516 dump_points_to_info_for (FILE *file, tree ptr)
518 struct ptr_info_def *pi = SSA_NAME_PTR_INFO (ptr);
520 print_generic_expr (file, ptr, dump_flags);
523 dump_points_to_solution (file, &pi->pt);
525 fprintf (file, ", points-to anything");
527 fprintf (file, "\n");
531 /* Dump points-to information for VAR into stderr. */
534 debug_points_to_info_for (tree var)
536 dump_points_to_info_for (stderr, var);
540 /* Initializes the alias-oracle reference representation *R from REF. */
543 ao_ref_init (ao_ref *r, tree ref)
550 r->ref_alias_set = -1;
551 r->base_alias_set = -1;
552 r->volatile_p = ref ? TREE_THIS_VOLATILE (ref) : false;
555 /* Returns the base object of the memory reference *REF. */
558 ao_ref_base (ao_ref *ref)
562 ref->base = get_ref_base_and_extent (ref->ref, &ref->offset, &ref->size,
567 /* Returns the base object alias set of the memory reference *REF. */
570 ao_ref_base_alias_set (ao_ref *ref)
573 if (ref->base_alias_set != -1)
574 return ref->base_alias_set;
578 while (handled_component_p (base_ref))
579 base_ref = TREE_OPERAND (base_ref, 0);
580 ref->base_alias_set = get_alias_set (base_ref);
581 return ref->base_alias_set;
584 /* Returns the reference alias set of the memory reference *REF. */
587 ao_ref_alias_set (ao_ref *ref)
589 if (ref->ref_alias_set != -1)
590 return ref->ref_alias_set;
591 ref->ref_alias_set = get_alias_set (ref->ref);
592 return ref->ref_alias_set;
595 /* Init an alias-oracle reference representation from a gimple pointer
596 PTR and a gimple size SIZE in bytes. If SIZE is NULL_TREE then the
597 size is assumed to be unknown. The access is assumed to be only
598 to or after of the pointer target, not before it. */
601 ao_ref_init_from_ptr_and_size (ao_ref *ref, tree ptr, tree size)
603 HOST_WIDE_INT t, size_hwi, extra_offset = 0;
604 ref->ref = NULL_TREE;
605 if (TREE_CODE (ptr) == SSA_NAME)
607 gimple *stmt = SSA_NAME_DEF_STMT (ptr);
608 if (gimple_assign_single_p (stmt)
609 && gimple_assign_rhs_code (stmt) == ADDR_EXPR)
610 ptr = gimple_assign_rhs1 (stmt);
611 else if (is_gimple_assign (stmt)
612 && gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR
613 && TREE_CODE (gimple_assign_rhs2 (stmt)) == INTEGER_CST)
615 ptr = gimple_assign_rhs1 (stmt);
616 extra_offset = BITS_PER_UNIT
617 * int_cst_value (gimple_assign_rhs2 (stmt));
621 if (TREE_CODE (ptr) == ADDR_EXPR)
623 ref->base = get_addr_base_and_unit_offset (TREE_OPERAND (ptr, 0), &t);
625 ref->offset = BITS_PER_UNIT * t;
630 ref->base = get_base_address (TREE_OPERAND (ptr, 0));
635 ref->base = build2 (MEM_REF, char_type_node,
636 ptr, null_pointer_node);
639 ref->offset += extra_offset;
641 && tree_fits_shwi_p (size)
642 && (size_hwi = tree_to_shwi (size)) <= HOST_WIDE_INT_MAX / BITS_PER_UNIT)
643 ref->max_size = ref->size = size_hwi * BITS_PER_UNIT;
645 ref->max_size = ref->size = -1;
646 ref->ref_alias_set = 0;
647 ref->base_alias_set = 0;
648 ref->volatile_p = false;
651 /* Return 1 if TYPE1 and TYPE2 are to be considered equivalent for the
652 purpose of TBAA. Return 0 if they are distinct and -1 if we cannot
656 same_type_for_tbaa (tree type1, tree type2)
658 type1 = TYPE_MAIN_VARIANT (type1);
659 type2 = TYPE_MAIN_VARIANT (type2);
661 /* If we would have to do structural comparison bail out. */
662 if (TYPE_STRUCTURAL_EQUALITY_P (type1)
663 || TYPE_STRUCTURAL_EQUALITY_P (type2))
666 /* Compare the canonical types. */
667 if (TYPE_CANONICAL (type1) == TYPE_CANONICAL (type2))
670 /* ??? Array types are not properly unified in all cases as we have
671 spurious changes in the index types for example. Removing this
672 causes all sorts of problems with the Fortran frontend. */
673 if (TREE_CODE (type1) == ARRAY_TYPE
674 && TREE_CODE (type2) == ARRAY_TYPE)
677 /* ??? In Ada, an lvalue of an unconstrained type can be used to access an
678 object of one of its constrained subtypes, e.g. when a function with an
679 unconstrained parameter passed by reference is called on an object and
680 inlined. But, even in the case of a fixed size, type and subtypes are
681 not equivalent enough as to share the same TYPE_CANONICAL, since this
682 would mean that conversions between them are useless, whereas they are
683 not (e.g. type and subtypes can have different modes). So, in the end,
684 they are only guaranteed to have the same alias set. */
685 if (get_alias_set (type1) == get_alias_set (type2))
688 /* The types are known to be not equal. */
692 /* Determine if the two component references REF1 and REF2 which are
693 based on access types TYPE1 and TYPE2 and of which at least one is based
694 on an indirect reference may alias. REF2 is the only one that can
695 be a decl in which case REF2_IS_DECL is true.
696 REF1_ALIAS_SET, BASE1_ALIAS_SET, REF2_ALIAS_SET and BASE2_ALIAS_SET
697 are the respective alias sets. */
700 aliasing_component_refs_p (tree ref1,
701 alias_set_type ref1_alias_set,
702 alias_set_type base1_alias_set,
703 HOST_WIDE_INT offset1, HOST_WIDE_INT max_size1,
705 alias_set_type ref2_alias_set,
706 alias_set_type base2_alias_set,
707 HOST_WIDE_INT offset2, HOST_WIDE_INT max_size2,
710 /* If one reference is a component references through pointers try to find a
711 common base and apply offset based disambiguation. This handles
713 struct A { int i; int j; } *q;
714 struct B { struct A a; int k; } *p;
715 disambiguating q->i and p->a.j. */
721 /* Choose bases and base types to search for. */
723 while (handled_component_p (base1))
724 base1 = TREE_OPERAND (base1, 0);
725 type1 = TREE_TYPE (base1);
727 while (handled_component_p (base2))
728 base2 = TREE_OPERAND (base2, 0);
729 type2 = TREE_TYPE (base2);
731 /* Now search for the type1 in the access path of ref2. This
732 would be a common base for doing offset based disambiguation on. */
734 while (handled_component_p (*refp)
735 && same_type_for_tbaa (TREE_TYPE (*refp), type1) == 0)
736 refp = &TREE_OPERAND (*refp, 0);
737 same_p = same_type_for_tbaa (TREE_TYPE (*refp), type1);
738 /* If we couldn't compare types we have to bail out. */
741 else if (same_p == 1)
743 HOST_WIDE_INT offadj, sztmp, msztmp;
744 get_ref_base_and_extent (*refp, &offadj, &sztmp, &msztmp);
746 get_ref_base_and_extent (base1, &offadj, &sztmp, &msztmp);
748 return ranges_overlap_p (offset1, max_size1, offset2, max_size2);
750 /* If we didn't find a common base, try the other way around. */
752 while (handled_component_p (*refp)
753 && same_type_for_tbaa (TREE_TYPE (*refp), type2) == 0)
754 refp = &TREE_OPERAND (*refp, 0);
755 same_p = same_type_for_tbaa (TREE_TYPE (*refp), type2);
756 /* If we couldn't compare types we have to bail out. */
759 else if (same_p == 1)
761 HOST_WIDE_INT offadj, sztmp, msztmp;
762 get_ref_base_and_extent (*refp, &offadj, &sztmp, &msztmp);
764 get_ref_base_and_extent (base2, &offadj, &sztmp, &msztmp);
766 return ranges_overlap_p (offset1, max_size1, offset2, max_size2);
769 /* If we have two type access paths B1.path1 and B2.path2 they may
770 only alias if either B1 is in B2.path2 or B2 is in B1.path1.
771 But we can still have a path that goes B1.path1...B2.path2 with
772 a part that we do not see. So we can only disambiguate now
773 if there is no B2 in the tail of path1 and no B1 on the
775 if (base1_alias_set == ref2_alias_set
776 || alias_set_subset_of (base1_alias_set, ref2_alias_set))
778 /* If this is ptr vs. decl then we know there is no ptr ... decl path. */
780 return (base2_alias_set == ref1_alias_set
781 || alias_set_subset_of (base2_alias_set, ref1_alias_set));
785 /* Return true if we can determine that component references REF1 and REF2,
786 that are within a common DECL, cannot overlap. */
789 nonoverlapping_component_refs_of_decl_p (tree ref1, tree ref2)
791 auto_vec<tree, 16> component_refs1;
792 auto_vec<tree, 16> component_refs2;
794 /* Create the stack of handled components for REF1. */
795 while (handled_component_p (ref1))
797 component_refs1.safe_push (ref1);
798 ref1 = TREE_OPERAND (ref1, 0);
800 if (TREE_CODE (ref1) == MEM_REF)
802 if (!integer_zerop (TREE_OPERAND (ref1, 1)))
804 ref1 = TREE_OPERAND (TREE_OPERAND (ref1, 0), 0);
807 /* Create the stack of handled components for REF2. */
808 while (handled_component_p (ref2))
810 component_refs2.safe_push (ref2);
811 ref2 = TREE_OPERAND (ref2, 0);
813 if (TREE_CODE (ref2) == MEM_REF)
815 if (!integer_zerop (TREE_OPERAND (ref2, 1)))
817 ref2 = TREE_OPERAND (TREE_OPERAND (ref2, 0), 0);
820 /* We must have the same base DECL. */
821 gcc_assert (ref1 == ref2);
823 /* Pop the stacks in parallel and examine the COMPONENT_REFs of the same
824 rank. This is sufficient because we start from the same DECL and you
825 cannot reference several fields at a time with COMPONENT_REFs (unlike
826 with ARRAY_RANGE_REFs for arrays) so you always need the same number
827 of them to access a sub-component, unless you're in a union, in which
828 case the return value will precisely be false. */
833 if (component_refs1.is_empty ())
835 ref1 = component_refs1.pop ();
837 while (!RECORD_OR_UNION_TYPE_P (TREE_TYPE (TREE_OPERAND (ref1, 0))));
841 if (component_refs2.is_empty ())
843 ref2 = component_refs2.pop ();
845 while (!RECORD_OR_UNION_TYPE_P (TREE_TYPE (TREE_OPERAND (ref2, 0))));
847 /* Beware of BIT_FIELD_REF. */
848 if (TREE_CODE (ref1) != COMPONENT_REF
849 || TREE_CODE (ref2) != COMPONENT_REF)
852 tree field1 = TREE_OPERAND (ref1, 1);
853 tree field2 = TREE_OPERAND (ref2, 1);
855 /* ??? We cannot simply use the type of operand #0 of the refs here
856 as the Fortran compiler smuggles type punning into COMPONENT_REFs
857 for common blocks instead of using unions like everyone else. */
858 tree type1 = DECL_CONTEXT (field1);
859 tree type2 = DECL_CONTEXT (field2);
861 /* We cannot disambiguate fields in a union or qualified union. */
862 if (type1 != type2 || TREE_CODE (type1) != RECORD_TYPE)
865 /* Different fields of the same record type cannot overlap.
866 ??? Bitfields can overlap at RTL level so punt on them. */
867 if (field1 != field2)
869 component_refs1.release ();
870 component_refs2.release ();
871 return !(DECL_BIT_FIELD (field1) && DECL_BIT_FIELD (field2));
876 component_refs1.release ();
877 component_refs2.release ();
881 /* qsort compare function to sort FIELD_DECLs after their
882 DECL_FIELD_CONTEXT TYPE_UID. */
885 ncr_compar (const void *field1_, const void *field2_)
887 const_tree field1 = *(const_tree *) const_cast <void *>(field1_);
888 const_tree field2 = *(const_tree *) const_cast <void *>(field2_);
889 unsigned int uid1 = TYPE_UID (DECL_FIELD_CONTEXT (field1));
890 unsigned int uid2 = TYPE_UID (DECL_FIELD_CONTEXT (field2));
893 else if (uid1 > uid2)
898 /* Return true if we can determine that the fields referenced cannot
899 overlap for any pair of objects. */
902 nonoverlapping_component_refs_p (const_tree x, const_tree y)
904 if (!flag_strict_aliasing
906 || TREE_CODE (x) != COMPONENT_REF
907 || TREE_CODE (y) != COMPONENT_REF)
910 auto_vec<const_tree, 16> fieldsx;
911 while (TREE_CODE (x) == COMPONENT_REF)
913 tree field = TREE_OPERAND (x, 1);
914 tree type = DECL_FIELD_CONTEXT (field);
915 if (TREE_CODE (type) == RECORD_TYPE)
916 fieldsx.safe_push (field);
917 x = TREE_OPERAND (x, 0);
919 if (fieldsx.length () == 0)
921 auto_vec<const_tree, 16> fieldsy;
922 while (TREE_CODE (y) == COMPONENT_REF)
924 tree field = TREE_OPERAND (y, 1);
925 tree type = DECL_FIELD_CONTEXT (field);
926 if (TREE_CODE (type) == RECORD_TYPE)
927 fieldsy.safe_push (TREE_OPERAND (y, 1));
928 y = TREE_OPERAND (y, 0);
930 if (fieldsy.length () == 0)
933 /* Most common case first. */
934 if (fieldsx.length () == 1
935 && fieldsy.length () == 1)
936 return ((DECL_FIELD_CONTEXT (fieldsx[0])
937 == DECL_FIELD_CONTEXT (fieldsy[0]))
938 && fieldsx[0] != fieldsy[0]
939 && !(DECL_BIT_FIELD (fieldsx[0]) && DECL_BIT_FIELD (fieldsy[0])));
941 if (fieldsx.length () == 2)
943 if (ncr_compar (&fieldsx[0], &fieldsx[1]) == 1)
944 std::swap (fieldsx[0], fieldsx[1]);
947 fieldsx.qsort (ncr_compar);
949 if (fieldsy.length () == 2)
951 if (ncr_compar (&fieldsy[0], &fieldsy[1]) == 1)
952 std::swap (fieldsy[0], fieldsy[1]);
955 fieldsy.qsort (ncr_compar);
957 unsigned i = 0, j = 0;
960 const_tree fieldx = fieldsx[i];
961 const_tree fieldy = fieldsy[j];
962 tree typex = DECL_FIELD_CONTEXT (fieldx);
963 tree typey = DECL_FIELD_CONTEXT (fieldy);
966 /* We're left with accessing different fields of a structure,
967 no possible overlap, unless they are both bitfields. */
968 if (fieldx != fieldy)
969 return !(DECL_BIT_FIELD (fieldx) && DECL_BIT_FIELD (fieldy));
971 if (TYPE_UID (typex) < TYPE_UID (typey))
974 if (i == fieldsx.length ())
980 if (j == fieldsy.length ())
990 /* Return true if two memory references based on the variables BASE1
991 and BASE2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and
992 [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. REF1 and REF2
993 if non-NULL are the complete memory reference trees. */
996 decl_refs_may_alias_p (tree ref1, tree base1,
997 HOST_WIDE_INT offset1, HOST_WIDE_INT max_size1,
998 tree ref2, tree base2,
999 HOST_WIDE_INT offset2, HOST_WIDE_INT max_size2)
1001 gcc_checking_assert (DECL_P (base1) && DECL_P (base2));
1003 /* If both references are based on different variables, they cannot alias. */
1007 /* If both references are based on the same variable, they cannot alias if
1008 the accesses do not overlap. */
1009 if (!ranges_overlap_p (offset1, max_size1, offset2, max_size2))
1012 /* For components with variable position, the above test isn't sufficient,
1013 so we disambiguate component references manually. */
1015 && handled_component_p (ref1) && handled_component_p (ref2)
1016 && nonoverlapping_component_refs_of_decl_p (ref1, ref2))
1022 /* Return true if an indirect reference based on *PTR1 constrained
1023 to [OFFSET1, OFFSET1 + MAX_SIZE1) may alias a variable based on BASE2
1024 constrained to [OFFSET2, OFFSET2 + MAX_SIZE2). *PTR1 and BASE2 have
1025 the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1
1026 in which case they are computed on-demand. REF1 and REF2
1027 if non-NULL are the complete memory reference trees. */
1030 indirect_ref_may_alias_decl_p (tree ref1 ATTRIBUTE_UNUSED, tree base1,
1031 HOST_WIDE_INT offset1,
1032 HOST_WIDE_INT max_size1 ATTRIBUTE_UNUSED,
1033 alias_set_type ref1_alias_set,
1034 alias_set_type base1_alias_set,
1035 tree ref2 ATTRIBUTE_UNUSED, tree base2,
1036 HOST_WIDE_INT offset2, HOST_WIDE_INT max_size2,
1037 alias_set_type ref2_alias_set,
1038 alias_set_type base2_alias_set, bool tbaa_p)
1041 tree ptrtype1, dbase2;
1042 HOST_WIDE_INT offset1p = offset1, offset2p = offset2;
1043 HOST_WIDE_INT doffset1, doffset2;
1045 gcc_checking_assert ((TREE_CODE (base1) == MEM_REF
1046 || TREE_CODE (base1) == TARGET_MEM_REF)
1049 ptr1 = TREE_OPERAND (base1, 0);
1051 /* The offset embedded in MEM_REFs can be negative. Bias them
1052 so that the resulting offset adjustment is positive. */
1053 offset_int moff = mem_ref_offset (base1);
1054 moff = wi::lshift (moff, LOG2_BITS_PER_UNIT);
1055 if (wi::neg_p (moff))
1056 offset2p += (-moff).to_short_addr ();
1058 offset1p += moff.to_short_addr ();
1060 /* If only one reference is based on a variable, they cannot alias if
1061 the pointer access is beyond the extent of the variable access.
1062 (the pointer base cannot validly point to an offset less than zero
1064 ??? IVOPTs creates bases that do not honor this restriction,
1065 so do not apply this optimization for TARGET_MEM_REFs. */
1066 if (TREE_CODE (base1) != TARGET_MEM_REF
1067 && !ranges_overlap_p (MAX (0, offset1p), -1, offset2p, max_size2))
1069 /* They also cannot alias if the pointer may not point to the decl. */
1070 if (!ptr_deref_may_alias_decl_p (ptr1, base2))
1073 /* Disambiguations that rely on strict aliasing rules follow. */
1074 if (!flag_strict_aliasing || !tbaa_p)
1077 ptrtype1 = TREE_TYPE (TREE_OPERAND (base1, 1));
1079 /* If the alias set for a pointer access is zero all bets are off. */
1080 if (base1_alias_set == -1)
1081 base1_alias_set = get_deref_alias_set (ptrtype1);
1082 if (base1_alias_set == 0)
1084 if (base2_alias_set == -1)
1085 base2_alias_set = get_alias_set (base2);
1087 /* When we are trying to disambiguate an access with a pointer dereference
1088 as base versus one with a decl as base we can use both the size
1089 of the decl and its dynamic type for extra disambiguation.
1090 ??? We do not know anything about the dynamic type of the decl
1091 other than that its alias-set contains base2_alias_set as a subset
1092 which does not help us here. */
1093 /* As we know nothing useful about the dynamic type of the decl just
1094 use the usual conflict check rather than a subset test.
1095 ??? We could introduce -fvery-strict-aliasing when the language
1096 does not allow decls to have a dynamic type that differs from their
1097 static type. Then we can check
1098 !alias_set_subset_of (base1_alias_set, base2_alias_set) instead. */
1099 if (base1_alias_set != base2_alias_set
1100 && !alias_sets_conflict_p (base1_alias_set, base2_alias_set))
1102 /* If the size of the access relevant for TBAA through the pointer
1103 is bigger than the size of the decl we can't possibly access the
1104 decl via that pointer. */
1105 if (DECL_SIZE (base2) && COMPLETE_TYPE_P (TREE_TYPE (ptrtype1))
1106 && TREE_CODE (DECL_SIZE (base2)) == INTEGER_CST
1107 && TREE_CODE (TYPE_SIZE (TREE_TYPE (ptrtype1))) == INTEGER_CST
1108 /* ??? This in turn may run afoul when a decl of type T which is
1109 a member of union type U is accessed through a pointer to
1110 type U and sizeof T is smaller than sizeof U. */
1111 && TREE_CODE (TREE_TYPE (ptrtype1)) != UNION_TYPE
1112 && TREE_CODE (TREE_TYPE (ptrtype1)) != QUAL_UNION_TYPE
1113 && tree_int_cst_lt (DECL_SIZE (base2), TYPE_SIZE (TREE_TYPE (ptrtype1))))
1119 /* If the decl is accessed via a MEM_REF, reconstruct the base
1120 we can use for TBAA and an appropriately adjusted offset. */
1122 while (handled_component_p (dbase2))
1123 dbase2 = TREE_OPERAND (dbase2, 0);
1126 if (TREE_CODE (dbase2) == MEM_REF
1127 || TREE_CODE (dbase2) == TARGET_MEM_REF)
1129 offset_int moff = mem_ref_offset (dbase2);
1130 moff = wi::lshift (moff, LOG2_BITS_PER_UNIT);
1131 if (wi::neg_p (moff))
1132 doffset1 -= (-moff).to_short_addr ();
1134 doffset2 -= moff.to_short_addr ();
1137 /* If either reference is view-converted, give up now. */
1138 if (same_type_for_tbaa (TREE_TYPE (base1), TREE_TYPE (ptrtype1)) != 1
1139 || same_type_for_tbaa (TREE_TYPE (dbase2), TREE_TYPE (base2)) != 1)
1142 /* If both references are through the same type, they do not alias
1143 if the accesses do not overlap. This does extra disambiguation
1144 for mixed/pointer accesses but requires strict aliasing.
1145 For MEM_REFs we require that the component-ref offset we computed
1146 is relative to the start of the type which we ensure by
1147 comparing rvalue and access type and disregarding the constant
1149 if ((TREE_CODE (base1) != TARGET_MEM_REF
1150 || (!TMR_INDEX (base1) && !TMR_INDEX2 (base1)))
1151 && same_type_for_tbaa (TREE_TYPE (base1), TREE_TYPE (dbase2)) == 1)
1152 return ranges_overlap_p (doffset1, max_size1, doffset2, max_size2);
1155 && nonoverlapping_component_refs_p (ref1, ref2))
1158 /* Do access-path based disambiguation. */
1160 && (handled_component_p (ref1) || handled_component_p (ref2)))
1161 return aliasing_component_refs_p (ref1,
1162 ref1_alias_set, base1_alias_set,
1165 ref2_alias_set, base2_alias_set,
1166 offset2, max_size2, true);
1171 /* Return true if two indirect references based on *PTR1
1172 and *PTR2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and
1173 [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. *PTR1 and *PTR2 have
1174 the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1
1175 in which case they are computed on-demand. REF1 and REF2
1176 if non-NULL are the complete memory reference trees. */
1179 indirect_refs_may_alias_p (tree ref1 ATTRIBUTE_UNUSED, tree base1,
1180 HOST_WIDE_INT offset1, HOST_WIDE_INT max_size1,
1181 alias_set_type ref1_alias_set,
1182 alias_set_type base1_alias_set,
1183 tree ref2 ATTRIBUTE_UNUSED, tree base2,
1184 HOST_WIDE_INT offset2, HOST_WIDE_INT max_size2,
1185 alias_set_type ref2_alias_set,
1186 alias_set_type base2_alias_set, bool tbaa_p)
1190 tree ptrtype1, ptrtype2;
1192 gcc_checking_assert ((TREE_CODE (base1) == MEM_REF
1193 || TREE_CODE (base1) == TARGET_MEM_REF)
1194 && (TREE_CODE (base2) == MEM_REF
1195 || TREE_CODE (base2) == TARGET_MEM_REF));
1197 ptr1 = TREE_OPERAND (base1, 0);
1198 ptr2 = TREE_OPERAND (base2, 0);
1200 /* If both bases are based on pointers they cannot alias if they may not
1201 point to the same memory object or if they point to the same object
1202 and the accesses do not overlap. */
1203 if ((!cfun || gimple_in_ssa_p (cfun))
1204 && operand_equal_p (ptr1, ptr2, 0)
1205 && (((TREE_CODE (base1) != TARGET_MEM_REF
1206 || (!TMR_INDEX (base1) && !TMR_INDEX2 (base1)))
1207 && (TREE_CODE (base2) != TARGET_MEM_REF
1208 || (!TMR_INDEX (base2) && !TMR_INDEX2 (base2))))
1209 || (TREE_CODE (base1) == TARGET_MEM_REF
1210 && TREE_CODE (base2) == TARGET_MEM_REF
1211 && (TMR_STEP (base1) == TMR_STEP (base2)
1212 || (TMR_STEP (base1) && TMR_STEP (base2)
1213 && operand_equal_p (TMR_STEP (base1),
1214 TMR_STEP (base2), 0)))
1215 && (TMR_INDEX (base1) == TMR_INDEX (base2)
1216 || (TMR_INDEX (base1) && TMR_INDEX (base2)
1217 && operand_equal_p (TMR_INDEX (base1),
1218 TMR_INDEX (base2), 0)))
1219 && (TMR_INDEX2 (base1) == TMR_INDEX2 (base2)
1220 || (TMR_INDEX2 (base1) && TMR_INDEX2 (base2)
1221 && operand_equal_p (TMR_INDEX2 (base1),
1222 TMR_INDEX2 (base2), 0))))))
1225 /* The offset embedded in MEM_REFs can be negative. Bias them
1226 so that the resulting offset adjustment is positive. */
1227 moff = mem_ref_offset (base1);
1228 moff = wi::lshift (moff, LOG2_BITS_PER_UNIT);
1229 if (wi::neg_p (moff))
1230 offset2 += (-moff).to_short_addr ();
1232 offset1 += moff.to_shwi ();
1233 moff = mem_ref_offset (base2);
1234 moff = wi::lshift (moff, LOG2_BITS_PER_UNIT);
1235 if (wi::neg_p (moff))
1236 offset1 += (-moff).to_short_addr ();
1238 offset2 += moff.to_short_addr ();
1239 return ranges_overlap_p (offset1, max_size1, offset2, max_size2);
1241 if (!ptr_derefs_may_alias_p (ptr1, ptr2))
1244 /* Disambiguations that rely on strict aliasing rules follow. */
1245 if (!flag_strict_aliasing || !tbaa_p)
1248 ptrtype1 = TREE_TYPE (TREE_OPERAND (base1, 1));
1249 ptrtype2 = TREE_TYPE (TREE_OPERAND (base2, 1));
1251 /* If the alias set for a pointer access is zero all bets are off. */
1252 if (base1_alias_set == -1)
1253 base1_alias_set = get_deref_alias_set (ptrtype1);
1254 if (base1_alias_set == 0)
1256 if (base2_alias_set == -1)
1257 base2_alias_set = get_deref_alias_set (ptrtype2);
1258 if (base2_alias_set == 0)
1261 /* If both references are through the same type, they do not alias
1262 if the accesses do not overlap. This does extra disambiguation
1263 for mixed/pointer accesses but requires strict aliasing. */
1264 if ((TREE_CODE (base1) != TARGET_MEM_REF
1265 || (!TMR_INDEX (base1) && !TMR_INDEX2 (base1)))
1266 && (TREE_CODE (base2) != TARGET_MEM_REF
1267 || (!TMR_INDEX (base2) && !TMR_INDEX2 (base2)))
1268 && same_type_for_tbaa (TREE_TYPE (base1), TREE_TYPE (ptrtype1)) == 1
1269 && same_type_for_tbaa (TREE_TYPE (base2), TREE_TYPE (ptrtype2)) == 1
1270 && same_type_for_tbaa (TREE_TYPE (ptrtype1),
1271 TREE_TYPE (ptrtype2)) == 1)
1272 return ranges_overlap_p (offset1, max_size1, offset2, max_size2);
1274 /* Do type-based disambiguation. */
1275 if (base1_alias_set != base2_alias_set
1276 && !alias_sets_conflict_p (base1_alias_set, base2_alias_set))
1279 /* If either reference is view-converted, give up now. */
1280 if (same_type_for_tbaa (TREE_TYPE (base1), TREE_TYPE (ptrtype1)) != 1
1281 || same_type_for_tbaa (TREE_TYPE (base2), TREE_TYPE (ptrtype2)) != 1)
1285 && nonoverlapping_component_refs_p (ref1, ref2))
1288 /* Do access-path based disambiguation. */
1290 && (handled_component_p (ref1) || handled_component_p (ref2)))
1291 return aliasing_component_refs_p (ref1,
1292 ref1_alias_set, base1_alias_set,
1295 ref2_alias_set, base2_alias_set,
1296 offset2, max_size2, false);
1301 /* Return true, if the two memory references REF1 and REF2 may alias. */
1304 refs_may_alias_p_1 (ao_ref *ref1, ao_ref *ref2, bool tbaa_p)
1307 HOST_WIDE_INT offset1 = 0, offset2 = 0;
1308 HOST_WIDE_INT max_size1 = -1, max_size2 = -1;
1309 bool var1_p, var2_p, ind1_p, ind2_p;
1311 gcc_checking_assert ((!ref1->ref
1312 || TREE_CODE (ref1->ref) == SSA_NAME
1313 || DECL_P (ref1->ref)
1314 || TREE_CODE (ref1->ref) == STRING_CST
1315 || handled_component_p (ref1->ref)
1316 || TREE_CODE (ref1->ref) == MEM_REF
1317 || TREE_CODE (ref1->ref) == TARGET_MEM_REF)
1319 || TREE_CODE (ref2->ref) == SSA_NAME
1320 || DECL_P (ref2->ref)
1321 || TREE_CODE (ref2->ref) == STRING_CST
1322 || handled_component_p (ref2->ref)
1323 || TREE_CODE (ref2->ref) == MEM_REF
1324 || TREE_CODE (ref2->ref) == TARGET_MEM_REF));
1326 /* Decompose the references into their base objects and the access. */
1327 base1 = ao_ref_base (ref1);
1328 offset1 = ref1->offset;
1329 max_size1 = ref1->max_size;
1330 base2 = ao_ref_base (ref2);
1331 offset2 = ref2->offset;
1332 max_size2 = ref2->max_size;
1334 /* We can end up with registers or constants as bases for example from
1335 *D.1663_44 = VIEW_CONVERT_EXPR<struct DB_LSN>(__tmp$B0F64_59);
1336 which is seen as a struct copy. */
1337 if (TREE_CODE (base1) == SSA_NAME
1338 || TREE_CODE (base1) == CONST_DECL
1339 || TREE_CODE (base1) == CONSTRUCTOR
1340 || TREE_CODE (base1) == ADDR_EXPR
1341 || CONSTANT_CLASS_P (base1)
1342 || TREE_CODE (base2) == SSA_NAME
1343 || TREE_CODE (base2) == CONST_DECL
1344 || TREE_CODE (base2) == CONSTRUCTOR
1345 || TREE_CODE (base2) == ADDR_EXPR
1346 || CONSTANT_CLASS_P (base2))
1349 /* We can end up referring to code via function and label decls.
1350 As we likely do not properly track code aliases conservatively
1352 if (TREE_CODE (base1) == FUNCTION_DECL
1353 || TREE_CODE (base1) == LABEL_DECL
1354 || TREE_CODE (base2) == FUNCTION_DECL
1355 || TREE_CODE (base2) == LABEL_DECL)
1358 /* Two volatile accesses always conflict. */
1359 if (ref1->volatile_p
1360 && ref2->volatile_p)
1363 /* Defer to simple offset based disambiguation if we have
1364 references based on two decls. Do this before defering to
1365 TBAA to handle must-alias cases in conformance with the
1366 GCC extension of allowing type-punning through unions. */
1367 var1_p = DECL_P (base1);
1368 var2_p = DECL_P (base2);
1369 if (var1_p && var2_p)
1370 return decl_refs_may_alias_p (ref1->ref, base1, offset1, max_size1,
1371 ref2->ref, base2, offset2, max_size2);
1373 /* Handle restrict based accesses.
1374 ??? ao_ref_base strips inner MEM_REF [&decl], recover from that
1376 tree rbase1 = base1;
1377 tree rbase2 = base2;
1382 while (handled_component_p (rbase1))
1383 rbase1 = TREE_OPERAND (rbase1, 0);
1389 while (handled_component_p (rbase2))
1390 rbase2 = TREE_OPERAND (rbase2, 0);
1392 if (rbase1 && rbase2
1393 && (TREE_CODE (base1) == MEM_REF || TREE_CODE (base1) == TARGET_MEM_REF)
1394 && (TREE_CODE (base2) == MEM_REF || TREE_CODE (base2) == TARGET_MEM_REF)
1395 /* If the accesses are in the same restrict clique... */
1396 && MR_DEPENDENCE_CLIQUE (base1) == MR_DEPENDENCE_CLIQUE (base2)
1397 /* But based on different pointers they do not alias. */
1398 && MR_DEPENDENCE_BASE (base1) != MR_DEPENDENCE_BASE (base2))
1401 ind1_p = (TREE_CODE (base1) == MEM_REF
1402 || TREE_CODE (base1) == TARGET_MEM_REF);
1403 ind2_p = (TREE_CODE (base2) == MEM_REF
1404 || TREE_CODE (base2) == TARGET_MEM_REF);
1406 /* Canonicalize the pointer-vs-decl case. */
1407 if (ind1_p && var2_p)
1409 std::swap (offset1, offset2);
1410 std::swap (max_size1, max_size2);
1411 std::swap (base1, base2);
1412 std::swap (ref1, ref2);
1419 /* First defer to TBAA if possible. */
1421 && flag_strict_aliasing
1422 && !alias_sets_conflict_p (ao_ref_alias_set (ref1),
1423 ao_ref_alias_set (ref2)))
1426 /* Dispatch to the pointer-vs-decl or pointer-vs-pointer disambiguators. */
1427 if (var1_p && ind2_p)
1428 return indirect_ref_may_alias_decl_p (ref2->ref, base2,
1430 ao_ref_alias_set (ref2), -1,
1433 ao_ref_alias_set (ref1),
1434 ao_ref_base_alias_set (ref1),
1436 else if (ind1_p && ind2_p)
1437 return indirect_refs_may_alias_p (ref1->ref, base1,
1439 ao_ref_alias_set (ref1), -1,
1442 ao_ref_alias_set (ref2), -1,
1449 refs_may_alias_p (tree ref1, ao_ref *ref2)
1452 ao_ref_init (&r1, ref1);
1453 return refs_may_alias_p_1 (&r1, ref2, true);
1457 refs_may_alias_p (tree ref1, tree ref2)
1461 ao_ref_init (&r1, ref1);
1462 ao_ref_init (&r2, ref2);
1463 res = refs_may_alias_p_1 (&r1, &r2, true);
1465 ++alias_stats.refs_may_alias_p_may_alias;
1467 ++alias_stats.refs_may_alias_p_no_alias;
1471 /* Returns true if there is a anti-dependence for the STORE that
1472 executes after the LOAD. */
1475 refs_anti_dependent_p (tree load, tree store)
1478 ao_ref_init (&r1, load);
1479 ao_ref_init (&r2, store);
1480 return refs_may_alias_p_1 (&r1, &r2, false);
1483 /* Returns true if there is a output dependence for the stores
1484 STORE1 and STORE2. */
1487 refs_output_dependent_p (tree store1, tree store2)
1490 ao_ref_init (&r1, store1);
1491 ao_ref_init (&r2, store2);
1492 return refs_may_alias_p_1 (&r1, &r2, false);
1495 /* If the call CALL may use the memory reference REF return true,
1496 otherwise return false. */
1499 ref_maybe_used_by_call_p_1 (gcall *call, ao_ref *ref)
1503 int flags = gimple_call_flags (call);
1505 /* Const functions without a static chain do not implicitly use memory. */
1506 if (!gimple_call_chain (call)
1507 && (flags & (ECF_CONST|ECF_NOVOPS)))
1510 base = ao_ref_base (ref);
1514 /* A call that is not without side-effects might involve volatile
1515 accesses and thus conflicts with all other volatile accesses. */
1516 if (ref->volatile_p)
1519 /* If the reference is based on a decl that is not aliased the call
1520 cannot possibly use it. */
1522 && !may_be_aliased (base)
1523 /* But local statics can be used through recursion. */
1524 && !is_global_var (base))
1527 callee = gimple_call_fndecl (call);
1529 /* Handle those builtin functions explicitly that do not act as
1530 escape points. See tree-ssa-structalias.c:find_func_aliases
1531 for the list of builtins we might need to handle here. */
1532 if (callee != NULL_TREE
1533 && gimple_call_builtin_p (call, BUILT_IN_NORMAL))
1534 switch (DECL_FUNCTION_CODE (callee))
1536 /* All the following functions read memory pointed to by
1537 their second argument. strcat/strncat additionally
1538 reads memory pointed to by the first argument. */
1539 case BUILT_IN_STRCAT:
1540 case BUILT_IN_STRNCAT:
1543 ao_ref_init_from_ptr_and_size (&dref,
1544 gimple_call_arg (call, 0),
1546 if (refs_may_alias_p_1 (&dref, ref, false))
1550 case BUILT_IN_STRCPY:
1551 case BUILT_IN_STRNCPY:
1552 case BUILT_IN_MEMCPY:
1553 case BUILT_IN_MEMMOVE:
1554 case BUILT_IN_MEMPCPY:
1555 case BUILT_IN_STPCPY:
1556 case BUILT_IN_STPNCPY:
1557 case BUILT_IN_TM_MEMCPY:
1558 case BUILT_IN_TM_MEMMOVE:
1561 tree size = NULL_TREE;
1562 if (gimple_call_num_args (call) == 3)
1563 size = gimple_call_arg (call, 2);
1564 ao_ref_init_from_ptr_and_size (&dref,
1565 gimple_call_arg (call, 1),
1567 return refs_may_alias_p_1 (&dref, ref, false);
1569 case BUILT_IN_STRCAT_CHK:
1570 case BUILT_IN_STRNCAT_CHK:
1573 ao_ref_init_from_ptr_and_size (&dref,
1574 gimple_call_arg (call, 0),
1576 if (refs_may_alias_p_1 (&dref, ref, false))
1580 case BUILT_IN_STRCPY_CHK:
1581 case BUILT_IN_STRNCPY_CHK:
1582 case BUILT_IN_MEMCPY_CHK:
1583 case BUILT_IN_MEMMOVE_CHK:
1584 case BUILT_IN_MEMPCPY_CHK:
1585 case BUILT_IN_STPCPY_CHK:
1586 case BUILT_IN_STPNCPY_CHK:
1589 tree size = NULL_TREE;
1590 if (gimple_call_num_args (call) == 4)
1591 size = gimple_call_arg (call, 2);
1592 ao_ref_init_from_ptr_and_size (&dref,
1593 gimple_call_arg (call, 1),
1595 return refs_may_alias_p_1 (&dref, ref, false);
1597 case BUILT_IN_BCOPY:
1600 tree size = gimple_call_arg (call, 2);
1601 ao_ref_init_from_ptr_and_size (&dref,
1602 gimple_call_arg (call, 0),
1604 return refs_may_alias_p_1 (&dref, ref, false);
1607 /* The following functions read memory pointed to by their
1609 CASE_BUILT_IN_TM_LOAD (1):
1610 CASE_BUILT_IN_TM_LOAD (2):
1611 CASE_BUILT_IN_TM_LOAD (4):
1612 CASE_BUILT_IN_TM_LOAD (8):
1613 CASE_BUILT_IN_TM_LOAD (FLOAT):
1614 CASE_BUILT_IN_TM_LOAD (DOUBLE):
1615 CASE_BUILT_IN_TM_LOAD (LDOUBLE):
1616 CASE_BUILT_IN_TM_LOAD (M64):
1617 CASE_BUILT_IN_TM_LOAD (M128):
1618 CASE_BUILT_IN_TM_LOAD (M256):
1619 case BUILT_IN_TM_LOG:
1620 case BUILT_IN_TM_LOG_1:
1621 case BUILT_IN_TM_LOG_2:
1622 case BUILT_IN_TM_LOG_4:
1623 case BUILT_IN_TM_LOG_8:
1624 case BUILT_IN_TM_LOG_FLOAT:
1625 case BUILT_IN_TM_LOG_DOUBLE:
1626 case BUILT_IN_TM_LOG_LDOUBLE:
1627 case BUILT_IN_TM_LOG_M64:
1628 case BUILT_IN_TM_LOG_M128:
1629 case BUILT_IN_TM_LOG_M256:
1630 return ptr_deref_may_alias_ref_p_1 (gimple_call_arg (call, 0), ref);
1632 /* These read memory pointed to by the first argument. */
1633 case BUILT_IN_STRDUP:
1634 case BUILT_IN_STRNDUP:
1635 case BUILT_IN_REALLOC:
1638 tree size = NULL_TREE;
1639 if (gimple_call_num_args (call) == 2)
1640 size = gimple_call_arg (call, 1);
1641 ao_ref_init_from_ptr_and_size (&dref,
1642 gimple_call_arg (call, 0),
1644 return refs_may_alias_p_1 (&dref, ref, false);
1646 /* These read memory pointed to by the first argument. */
1647 case BUILT_IN_INDEX:
1648 case BUILT_IN_STRCHR:
1649 case BUILT_IN_STRRCHR:
1652 ao_ref_init_from_ptr_and_size (&dref,
1653 gimple_call_arg (call, 0),
1655 return refs_may_alias_p_1 (&dref, ref, false);
1657 /* These read memory pointed to by the first argument with size
1658 in the third argument. */
1659 case BUILT_IN_MEMCHR:
1662 ao_ref_init_from_ptr_and_size (&dref,
1663 gimple_call_arg (call, 0),
1664 gimple_call_arg (call, 2));
1665 return refs_may_alias_p_1 (&dref, ref, false);
1667 /* These read memory pointed to by the first and second arguments. */
1668 case BUILT_IN_STRSTR:
1669 case BUILT_IN_STRPBRK:
1672 ao_ref_init_from_ptr_and_size (&dref,
1673 gimple_call_arg (call, 0),
1675 if (refs_may_alias_p_1 (&dref, ref, false))
1677 ao_ref_init_from_ptr_and_size (&dref,
1678 gimple_call_arg (call, 1),
1680 return refs_may_alias_p_1 (&dref, ref, false);
1683 /* The following builtins do not read from memory. */
1685 case BUILT_IN_MALLOC:
1686 case BUILT_IN_POSIX_MEMALIGN:
1687 case BUILT_IN_ALIGNED_ALLOC:
1688 case BUILT_IN_CALLOC:
1689 case BUILT_IN_ALLOCA:
1690 case BUILT_IN_ALLOCA_WITH_ALIGN:
1691 case BUILT_IN_STACK_SAVE:
1692 case BUILT_IN_STACK_RESTORE:
1693 case BUILT_IN_MEMSET:
1694 case BUILT_IN_TM_MEMSET:
1695 case BUILT_IN_MEMSET_CHK:
1696 case BUILT_IN_FREXP:
1697 case BUILT_IN_FREXPF:
1698 case BUILT_IN_FREXPL:
1699 case BUILT_IN_GAMMA_R:
1700 case BUILT_IN_GAMMAF_R:
1701 case BUILT_IN_GAMMAL_R:
1702 case BUILT_IN_LGAMMA_R:
1703 case BUILT_IN_LGAMMAF_R:
1704 case BUILT_IN_LGAMMAL_R:
1706 case BUILT_IN_MODFF:
1707 case BUILT_IN_MODFL:
1708 case BUILT_IN_REMQUO:
1709 case BUILT_IN_REMQUOF:
1710 case BUILT_IN_REMQUOL:
1711 case BUILT_IN_SINCOS:
1712 case BUILT_IN_SINCOSF:
1713 case BUILT_IN_SINCOSL:
1714 case BUILT_IN_ASSUME_ALIGNED:
1715 case BUILT_IN_VA_END:
1717 /* __sync_* builtins and some OpenMP builtins act as threading
1719 #undef DEF_SYNC_BUILTIN
1720 #define DEF_SYNC_BUILTIN(ENUM, NAME, TYPE, ATTRS) case ENUM:
1721 #include "sync-builtins.def"
1722 #undef DEF_SYNC_BUILTIN
1723 case BUILT_IN_GOMP_ATOMIC_START:
1724 case BUILT_IN_GOMP_ATOMIC_END:
1725 case BUILT_IN_GOMP_BARRIER:
1726 case BUILT_IN_GOMP_BARRIER_CANCEL:
1727 case BUILT_IN_GOMP_TASKWAIT:
1728 case BUILT_IN_GOMP_TASKGROUP_END:
1729 case BUILT_IN_GOMP_CRITICAL_START:
1730 case BUILT_IN_GOMP_CRITICAL_END:
1731 case BUILT_IN_GOMP_CRITICAL_NAME_START:
1732 case BUILT_IN_GOMP_CRITICAL_NAME_END:
1733 case BUILT_IN_GOMP_LOOP_END:
1734 case BUILT_IN_GOMP_LOOP_END_CANCEL:
1735 case BUILT_IN_GOMP_ORDERED_START:
1736 case BUILT_IN_GOMP_ORDERED_END:
1737 case BUILT_IN_GOMP_SECTIONS_END:
1738 case BUILT_IN_GOMP_SECTIONS_END_CANCEL:
1739 case BUILT_IN_GOMP_SINGLE_COPY_START:
1740 case BUILT_IN_GOMP_SINGLE_COPY_END:
1744 /* Fallthru to general call handling. */;
1747 /* Check if base is a global static variable that is not read
1749 if (callee != NULL_TREE
1750 && TREE_CODE (base) == VAR_DECL
1751 && TREE_STATIC (base))
1753 struct cgraph_node *node = cgraph_node::get (callee);
1756 /* FIXME: Callee can be an OMP builtin that does not have a call graph
1757 node yet. We should enforce that there are nodes for all decls in the
1758 IL and remove this check instead. */
1760 && (not_read = ipa_reference_get_not_read_global (node))
1761 && bitmap_bit_p (not_read, DECL_UID (base)))
1765 /* Check if the base variable is call-used. */
1768 if (pt_solution_includes (gimple_call_use_set (call), base))
1771 else if ((TREE_CODE (base) == MEM_REF
1772 || TREE_CODE (base) == TARGET_MEM_REF)
1773 && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME)
1775 struct ptr_info_def *pi = SSA_NAME_PTR_INFO (TREE_OPERAND (base, 0));
1779 if (pt_solutions_intersect (gimple_call_use_set (call), &pi->pt))
1785 /* Inspect call arguments for passed-by-value aliases. */
1787 for (i = 0; i < gimple_call_num_args (call); ++i)
1789 tree op = gimple_call_arg (call, i);
1790 int flags = gimple_call_arg_flags (call, i);
1792 if (flags & EAF_UNUSED)
1795 if (TREE_CODE (op) == WITH_SIZE_EXPR)
1796 op = TREE_OPERAND (op, 0);
1798 if (TREE_CODE (op) != SSA_NAME
1799 && !is_gimple_min_invariant (op))
1802 ao_ref_init (&r, op);
1803 if (refs_may_alias_p_1 (&r, ref, true))
1812 ref_maybe_used_by_call_p (gcall *call, ao_ref *ref)
1815 res = ref_maybe_used_by_call_p_1 (call, ref);
1817 ++alias_stats.ref_maybe_used_by_call_p_may_alias;
1819 ++alias_stats.ref_maybe_used_by_call_p_no_alias;
1824 /* If the statement STMT may use the memory reference REF return
1825 true, otherwise return false. */
1828 ref_maybe_used_by_stmt_p (gimple *stmt, ao_ref *ref)
1830 if (is_gimple_assign (stmt))
1834 /* All memory assign statements are single. */
1835 if (!gimple_assign_single_p (stmt))
1838 rhs = gimple_assign_rhs1 (stmt);
1839 if (is_gimple_reg (rhs)
1840 || is_gimple_min_invariant (rhs)
1841 || gimple_assign_rhs_code (stmt) == CONSTRUCTOR)
1844 return refs_may_alias_p (rhs, ref);
1846 else if (is_gimple_call (stmt))
1847 return ref_maybe_used_by_call_p (as_a <gcall *> (stmt), ref);
1848 else if (greturn *return_stmt = dyn_cast <greturn *> (stmt))
1850 tree retval = gimple_return_retval (return_stmt);
1852 && TREE_CODE (retval) != SSA_NAME
1853 && !is_gimple_min_invariant (retval)
1854 && refs_may_alias_p (retval, ref))
1856 /* If ref escapes the function then the return acts as a use. */
1857 tree base = ao_ref_base (ref);
1860 else if (DECL_P (base))
1861 return is_global_var (base);
1862 else if (TREE_CODE (base) == MEM_REF
1863 || TREE_CODE (base) == TARGET_MEM_REF)
1864 return ptr_deref_may_alias_global_p (TREE_OPERAND (base, 0));
1872 ref_maybe_used_by_stmt_p (gimple *stmt, tree ref)
1875 ao_ref_init (&r, ref);
1876 return ref_maybe_used_by_stmt_p (stmt, &r);
1879 /* If the call in statement CALL may clobber the memory reference REF
1880 return true, otherwise return false. */
1883 call_may_clobber_ref_p_1 (gcall *call, ao_ref *ref)
1888 /* If the call is pure or const it cannot clobber anything. */
1889 if (gimple_call_flags (call)
1890 & (ECF_PURE|ECF_CONST|ECF_LOOPING_CONST_OR_PURE|ECF_NOVOPS))
1892 if (gimple_call_internal_p (call))
1893 switch (gimple_call_internal_fn (call))
1895 /* Treat these internal calls like ECF_PURE for aliasing,
1896 they don't write to any memory the program should care about.
1897 They have important other side-effects, and read memory,
1898 so can't be ECF_NOVOPS. */
1899 case IFN_UBSAN_NULL:
1900 case IFN_UBSAN_BOUNDS:
1901 case IFN_UBSAN_VPTR:
1902 case IFN_UBSAN_OBJECT_SIZE:
1903 case IFN_ASAN_CHECK:
1909 base = ao_ref_base (ref);
1913 if (TREE_CODE (base) == SSA_NAME
1914 || CONSTANT_CLASS_P (base))
1917 /* A call that is not without side-effects might involve volatile
1918 accesses and thus conflicts with all other volatile accesses. */
1919 if (ref->volatile_p)
1922 /* If the reference is based on a decl that is not aliased the call
1923 cannot possibly clobber it. */
1925 && !may_be_aliased (base)
1926 /* But local non-readonly statics can be modified through recursion
1927 or the call may implement a threading barrier which we must
1928 treat as may-def. */
1929 && (TREE_READONLY (base)
1930 || !is_global_var (base)))
1933 callee = gimple_call_fndecl (call);
1935 /* Handle those builtin functions explicitly that do not act as
1936 escape points. See tree-ssa-structalias.c:find_func_aliases
1937 for the list of builtins we might need to handle here. */
1938 if (callee != NULL_TREE
1939 && gimple_call_builtin_p (call, BUILT_IN_NORMAL))
1940 switch (DECL_FUNCTION_CODE (callee))
1942 /* All the following functions clobber memory pointed to by
1943 their first argument. */
1944 case BUILT_IN_STRCPY:
1945 case BUILT_IN_STRNCPY:
1946 case BUILT_IN_MEMCPY:
1947 case BUILT_IN_MEMMOVE:
1948 case BUILT_IN_MEMPCPY:
1949 case BUILT_IN_STPCPY:
1950 case BUILT_IN_STPNCPY:
1951 case BUILT_IN_STRCAT:
1952 case BUILT_IN_STRNCAT:
1953 case BUILT_IN_MEMSET:
1954 case BUILT_IN_TM_MEMSET:
1955 CASE_BUILT_IN_TM_STORE (1):
1956 CASE_BUILT_IN_TM_STORE (2):
1957 CASE_BUILT_IN_TM_STORE (4):
1958 CASE_BUILT_IN_TM_STORE (8):
1959 CASE_BUILT_IN_TM_STORE (FLOAT):
1960 CASE_BUILT_IN_TM_STORE (DOUBLE):
1961 CASE_BUILT_IN_TM_STORE (LDOUBLE):
1962 CASE_BUILT_IN_TM_STORE (M64):
1963 CASE_BUILT_IN_TM_STORE (M128):
1964 CASE_BUILT_IN_TM_STORE (M256):
1965 case BUILT_IN_TM_MEMCPY:
1966 case BUILT_IN_TM_MEMMOVE:
1969 tree size = NULL_TREE;
1970 /* Don't pass in size for strncat, as the maximum size
1971 is strlen (dest) + n + 1 instead of n, resp.
1972 n + 1 at dest + strlen (dest), but strlen (dest) isn't
1974 if (gimple_call_num_args (call) == 3
1975 && DECL_FUNCTION_CODE (callee) != BUILT_IN_STRNCAT)
1976 size = gimple_call_arg (call, 2);
1977 ao_ref_init_from_ptr_and_size (&dref,
1978 gimple_call_arg (call, 0),
1980 return refs_may_alias_p_1 (&dref, ref, false);
1982 case BUILT_IN_STRCPY_CHK:
1983 case BUILT_IN_STRNCPY_CHK:
1984 case BUILT_IN_MEMCPY_CHK:
1985 case BUILT_IN_MEMMOVE_CHK:
1986 case BUILT_IN_MEMPCPY_CHK:
1987 case BUILT_IN_STPCPY_CHK:
1988 case BUILT_IN_STPNCPY_CHK:
1989 case BUILT_IN_STRCAT_CHK:
1990 case BUILT_IN_STRNCAT_CHK:
1991 case BUILT_IN_MEMSET_CHK:
1994 tree size = NULL_TREE;
1995 /* Don't pass in size for __strncat_chk, as the maximum size
1996 is strlen (dest) + n + 1 instead of n, resp.
1997 n + 1 at dest + strlen (dest), but strlen (dest) isn't
1999 if (gimple_call_num_args (call) == 4
2000 && DECL_FUNCTION_CODE (callee) != BUILT_IN_STRNCAT_CHK)
2001 size = gimple_call_arg (call, 2);
2002 ao_ref_init_from_ptr_and_size (&dref,
2003 gimple_call_arg (call, 0),
2005 return refs_may_alias_p_1 (&dref, ref, false);
2007 case BUILT_IN_BCOPY:
2010 tree size = gimple_call_arg (call, 2);
2011 ao_ref_init_from_ptr_and_size (&dref,
2012 gimple_call_arg (call, 1),
2014 return refs_may_alias_p_1 (&dref, ref, false);
2016 /* Allocating memory does not have any side-effects apart from
2017 being the definition point for the pointer. */
2018 case BUILT_IN_MALLOC:
2019 case BUILT_IN_ALIGNED_ALLOC:
2020 case BUILT_IN_CALLOC:
2021 case BUILT_IN_STRDUP:
2022 case BUILT_IN_STRNDUP:
2023 /* Unix98 specifies that errno is set on allocation failure. */
2025 && targetm.ref_may_alias_errno (ref))
2028 case BUILT_IN_STACK_SAVE:
2029 case BUILT_IN_ALLOCA:
2030 case BUILT_IN_ALLOCA_WITH_ALIGN:
2031 case BUILT_IN_ASSUME_ALIGNED:
2033 /* But posix_memalign stores a pointer into the memory pointed to
2034 by its first argument. */
2035 case BUILT_IN_POSIX_MEMALIGN:
2037 tree ptrptr = gimple_call_arg (call, 0);
2039 ao_ref_init_from_ptr_and_size (&dref, ptrptr,
2040 TYPE_SIZE_UNIT (ptr_type_node));
2041 return (refs_may_alias_p_1 (&dref, ref, false)
2043 && targetm.ref_may_alias_errno (ref)));
2045 /* Freeing memory kills the pointed-to memory. More importantly
2046 the call has to serve as a barrier for moving loads and stores
2049 case BUILT_IN_VA_END:
2051 tree ptr = gimple_call_arg (call, 0);
2052 return ptr_deref_may_alias_ref_p_1 (ptr, ref);
2054 /* Realloc serves both as allocation point and deallocation point. */
2055 case BUILT_IN_REALLOC:
2057 tree ptr = gimple_call_arg (call, 0);
2058 /* Unix98 specifies that errno is set on allocation failure. */
2059 return ((flag_errno_math
2060 && targetm.ref_may_alias_errno (ref))
2061 || ptr_deref_may_alias_ref_p_1 (ptr, ref));
2063 case BUILT_IN_GAMMA_R:
2064 case BUILT_IN_GAMMAF_R:
2065 case BUILT_IN_GAMMAL_R:
2066 case BUILT_IN_LGAMMA_R:
2067 case BUILT_IN_LGAMMAF_R:
2068 case BUILT_IN_LGAMMAL_R:
2070 tree out = gimple_call_arg (call, 1);
2071 if (ptr_deref_may_alias_ref_p_1 (out, ref))
2073 if (flag_errno_math)
2077 case BUILT_IN_FREXP:
2078 case BUILT_IN_FREXPF:
2079 case BUILT_IN_FREXPL:
2081 case BUILT_IN_MODFF:
2082 case BUILT_IN_MODFL:
2084 tree out = gimple_call_arg (call, 1);
2085 return ptr_deref_may_alias_ref_p_1 (out, ref);
2087 case BUILT_IN_REMQUO:
2088 case BUILT_IN_REMQUOF:
2089 case BUILT_IN_REMQUOL:
2091 tree out = gimple_call_arg (call, 2);
2092 if (ptr_deref_may_alias_ref_p_1 (out, ref))
2094 if (flag_errno_math)
2098 case BUILT_IN_SINCOS:
2099 case BUILT_IN_SINCOSF:
2100 case BUILT_IN_SINCOSL:
2102 tree sin = gimple_call_arg (call, 1);
2103 tree cos = gimple_call_arg (call, 2);
2104 return (ptr_deref_may_alias_ref_p_1 (sin, ref)
2105 || ptr_deref_may_alias_ref_p_1 (cos, ref));
2107 /* __sync_* builtins and some OpenMP builtins act as threading
2109 #undef DEF_SYNC_BUILTIN
2110 #define DEF_SYNC_BUILTIN(ENUM, NAME, TYPE, ATTRS) case ENUM:
2111 #include "sync-builtins.def"
2112 #undef DEF_SYNC_BUILTIN
2113 case BUILT_IN_GOMP_ATOMIC_START:
2114 case BUILT_IN_GOMP_ATOMIC_END:
2115 case BUILT_IN_GOMP_BARRIER:
2116 case BUILT_IN_GOMP_BARRIER_CANCEL:
2117 case BUILT_IN_GOMP_TASKWAIT:
2118 case BUILT_IN_GOMP_TASKGROUP_END:
2119 case BUILT_IN_GOMP_CRITICAL_START:
2120 case BUILT_IN_GOMP_CRITICAL_END:
2121 case BUILT_IN_GOMP_CRITICAL_NAME_START:
2122 case BUILT_IN_GOMP_CRITICAL_NAME_END:
2123 case BUILT_IN_GOMP_LOOP_END:
2124 case BUILT_IN_GOMP_LOOP_END_CANCEL:
2125 case BUILT_IN_GOMP_ORDERED_START:
2126 case BUILT_IN_GOMP_ORDERED_END:
2127 case BUILT_IN_GOMP_SECTIONS_END:
2128 case BUILT_IN_GOMP_SECTIONS_END_CANCEL:
2129 case BUILT_IN_GOMP_SINGLE_COPY_START:
2130 case BUILT_IN_GOMP_SINGLE_COPY_END:
2133 /* Fallthru to general call handling. */;
2136 /* Check if base is a global static variable that is not written
2138 if (callee != NULL_TREE
2139 && TREE_CODE (base) == VAR_DECL
2140 && TREE_STATIC (base))
2142 struct cgraph_node *node = cgraph_node::get (callee);
2146 && (not_written = ipa_reference_get_not_written_global (node))
2147 && bitmap_bit_p (not_written, DECL_UID (base)))
2151 /* Check if the base variable is call-clobbered. */
2153 return pt_solution_includes (gimple_call_clobber_set (call), base);
2154 else if ((TREE_CODE (base) == MEM_REF
2155 || TREE_CODE (base) == TARGET_MEM_REF)
2156 && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME)
2158 struct ptr_info_def *pi = SSA_NAME_PTR_INFO (TREE_OPERAND (base, 0));
2162 return pt_solutions_intersect (gimple_call_clobber_set (call), &pi->pt);
2168 /* If the call in statement CALL may clobber the memory reference REF
2169 return true, otherwise return false. */
2172 call_may_clobber_ref_p (gcall *call, tree ref)
2176 ao_ref_init (&r, ref);
2177 res = call_may_clobber_ref_p_1 (call, &r);
2179 ++alias_stats.call_may_clobber_ref_p_may_alias;
2181 ++alias_stats.call_may_clobber_ref_p_no_alias;
2186 /* If the statement STMT may clobber the memory reference REF return true,
2187 otherwise return false. */
2190 stmt_may_clobber_ref_p_1 (gimple *stmt, ao_ref *ref)
2192 if (is_gimple_call (stmt))
2194 tree lhs = gimple_call_lhs (stmt);
2196 && TREE_CODE (lhs) != SSA_NAME)
2199 ao_ref_init (&r, lhs);
2200 if (refs_may_alias_p_1 (ref, &r, true))
2204 return call_may_clobber_ref_p_1 (as_a <gcall *> (stmt), ref);
2206 else if (gimple_assign_single_p (stmt))
2208 tree lhs = gimple_assign_lhs (stmt);
2209 if (TREE_CODE (lhs) != SSA_NAME)
2212 ao_ref_init (&r, lhs);
2213 return refs_may_alias_p_1 (ref, &r, true);
2216 else if (gimple_code (stmt) == GIMPLE_ASM)
2223 stmt_may_clobber_ref_p (gimple *stmt, tree ref)
2226 ao_ref_init (&r, ref);
2227 return stmt_may_clobber_ref_p_1 (stmt, &r);
2230 /* If STMT kills the memory reference REF return true, otherwise
2234 stmt_kills_ref_p (gimple *stmt, ao_ref *ref)
2236 if (!ao_ref_base (ref))
2239 if (gimple_has_lhs (stmt)
2240 && TREE_CODE (gimple_get_lhs (stmt)) != SSA_NAME
2241 /* The assignment is not necessarily carried out if it can throw
2242 and we can catch it in the current function where we could inspect
2244 ??? We only need to care about the RHS throwing. For aggregate
2245 assignments or similar calls and non-call exceptions the LHS
2246 might throw as well. */
2247 && !stmt_can_throw_internal (stmt))
2249 tree lhs = gimple_get_lhs (stmt);
2250 /* If LHS is literally a base of the access we are done. */
2253 tree base = ref->ref;
2254 if (handled_component_p (base))
2256 tree saved_lhs0 = NULL_TREE;
2257 if (handled_component_p (lhs))
2259 saved_lhs0 = TREE_OPERAND (lhs, 0);
2260 TREE_OPERAND (lhs, 0) = integer_zero_node;
2264 /* Just compare the outermost handled component, if
2265 they are equal we have found a possible common
2267 tree saved_base0 = TREE_OPERAND (base, 0);
2268 TREE_OPERAND (base, 0) = integer_zero_node;
2269 bool res = operand_equal_p (lhs, base, 0);
2270 TREE_OPERAND (base, 0) = saved_base0;
2273 /* Otherwise drop handled components of the access. */
2276 while (handled_component_p (base));
2278 TREE_OPERAND (lhs, 0) = saved_lhs0;
2280 /* Finally check if the lhs has the same address and size as the
2281 base candidate of the access. */
2283 || (((TYPE_SIZE (TREE_TYPE (lhs))
2284 == TYPE_SIZE (TREE_TYPE (base)))
2285 || (TYPE_SIZE (TREE_TYPE (lhs))
2286 && TYPE_SIZE (TREE_TYPE (base))
2287 && operand_equal_p (TYPE_SIZE (TREE_TYPE (lhs)),
2288 TYPE_SIZE (TREE_TYPE (base)), 0)))
2289 && operand_equal_p (lhs, base, OEP_ADDRESS_OF)))
2293 /* Now look for non-literal equal bases with the restriction of
2294 handling constant offset and size. */
2295 /* For a must-alias check we need to be able to constrain
2296 the access properly. */
2297 if (ref->max_size == -1)
2299 HOST_WIDE_INT size, offset, max_size, ref_offset = ref->offset;
2300 tree base = get_ref_base_and_extent (lhs, &offset, &size, &max_size);
2301 /* We can get MEM[symbol: sZ, index: D.8862_1] here,
2302 so base == ref->base does not always hold. */
2303 if (base != ref->base)
2305 /* If both base and ref->base are MEM_REFs, only compare the
2306 first operand, and if the second operand isn't equal constant,
2307 try to add the offsets into offset and ref_offset. */
2308 if (TREE_CODE (base) == MEM_REF && TREE_CODE (ref->base) == MEM_REF
2309 && TREE_OPERAND (base, 0) == TREE_OPERAND (ref->base, 0))
2311 if (!tree_int_cst_equal (TREE_OPERAND (base, 1),
2312 TREE_OPERAND (ref->base, 1)))
2314 offset_int off1 = mem_ref_offset (base);
2315 off1 = wi::lshift (off1, LOG2_BITS_PER_UNIT);
2317 offset_int off2 = mem_ref_offset (ref->base);
2318 off2 = wi::lshift (off2, LOG2_BITS_PER_UNIT);
2320 if (wi::fits_shwi_p (off1) && wi::fits_shwi_p (off2))
2322 offset = off1.to_shwi ();
2323 ref_offset = off2.to_shwi ();
2332 /* For a must-alias check we need to be able to constrain
2333 the access properly. */
2334 if (size != -1 && size == max_size)
2336 if (offset <= ref_offset
2337 && offset + size >= ref_offset + ref->max_size)
2342 if (is_gimple_call (stmt))
2344 tree callee = gimple_call_fndecl (stmt);
2345 if (callee != NULL_TREE
2346 && gimple_call_builtin_p (stmt, BUILT_IN_NORMAL))
2347 switch (DECL_FUNCTION_CODE (callee))
2351 tree ptr = gimple_call_arg (stmt, 0);
2352 tree base = ao_ref_base (ref);
2353 if (base && TREE_CODE (base) == MEM_REF
2354 && TREE_OPERAND (base, 0) == ptr)
2359 case BUILT_IN_MEMCPY:
2360 case BUILT_IN_MEMPCPY:
2361 case BUILT_IN_MEMMOVE:
2362 case BUILT_IN_MEMSET:
2363 case BUILT_IN_MEMCPY_CHK:
2364 case BUILT_IN_MEMPCPY_CHK:
2365 case BUILT_IN_MEMMOVE_CHK:
2366 case BUILT_IN_MEMSET_CHK:
2368 /* For a must-alias check we need to be able to constrain
2369 the access properly. */
2370 if (ref->max_size == -1)
2372 tree dest = gimple_call_arg (stmt, 0);
2373 tree len = gimple_call_arg (stmt, 2);
2374 if (!tree_fits_shwi_p (len))
2376 tree rbase = ref->base;
2377 offset_int roffset = ref->offset;
2379 ao_ref_init_from_ptr_and_size (&dref, dest, len);
2380 tree base = ao_ref_base (&dref);
2381 offset_int offset = dref.offset;
2382 if (!base || dref.size == -1)
2384 if (TREE_CODE (base) == MEM_REF)
2386 if (TREE_CODE (rbase) != MEM_REF)
2388 // Compare pointers.
2389 offset += wi::lshift (mem_ref_offset (base),
2390 LOG2_BITS_PER_UNIT);
2391 roffset += wi::lshift (mem_ref_offset (rbase),
2392 LOG2_BITS_PER_UNIT);
2393 base = TREE_OPERAND (base, 0);
2394 rbase = TREE_OPERAND (rbase, 0);
2397 && wi::les_p (offset, roffset)
2398 && wi::les_p (roffset + ref->max_size,
2399 offset + wi::lshift (wi::to_offset (len),
2400 LOG2_BITS_PER_UNIT)))
2405 case BUILT_IN_VA_END:
2407 tree ptr = gimple_call_arg (stmt, 0);
2408 if (TREE_CODE (ptr) == ADDR_EXPR)
2410 tree base = ao_ref_base (ref);
2411 if (TREE_OPERAND (ptr, 0) == base)
2424 stmt_kills_ref_p (gimple *stmt, tree ref)
2427 ao_ref_init (&r, ref);
2428 return stmt_kills_ref_p (stmt, &r);
2432 /* Walk the virtual use-def chain of VUSE until hitting the virtual operand
2433 TARGET or a statement clobbering the memory reference REF in which
2434 case false is returned. The walk starts with VUSE, one argument of PHI. */
2437 maybe_skip_until (gimple *phi, tree target, ao_ref *ref,
2438 tree vuse, unsigned int *cnt, bitmap *visited,
2439 bool abort_on_visited,
2440 void *(*translate)(ao_ref *, tree, void *, bool *),
2443 basic_block bb = gimple_bb (phi);
2446 *visited = BITMAP_ALLOC (NULL);
2448 bitmap_set_bit (*visited, SSA_NAME_VERSION (PHI_RESULT (phi)));
2450 /* Walk until we hit the target. */
2451 while (vuse != target)
2453 gimple *def_stmt = SSA_NAME_DEF_STMT (vuse);
2454 /* Recurse for PHI nodes. */
2455 if (gimple_code (def_stmt) == GIMPLE_PHI)
2457 /* An already visited PHI node ends the walk successfully. */
2458 if (bitmap_bit_p (*visited, SSA_NAME_VERSION (PHI_RESULT (def_stmt))))
2459 return !abort_on_visited;
2460 vuse = get_continuation_for_phi (def_stmt, ref, cnt,
2461 visited, abort_on_visited,
2467 else if (gimple_nop_p (def_stmt))
2471 /* A clobbering statement or the end of the IL ends it failing. */
2473 if (stmt_may_clobber_ref_p_1 (def_stmt, ref))
2475 bool disambiguate_only = true;
2477 && (*translate) (ref, vuse, data, &disambiguate_only) == NULL)
2483 /* If we reach a new basic-block see if we already skipped it
2484 in a previous walk that ended successfully. */
2485 if (gimple_bb (def_stmt) != bb)
2487 if (!bitmap_set_bit (*visited, SSA_NAME_VERSION (vuse)))
2488 return !abort_on_visited;
2489 bb = gimple_bb (def_stmt);
2491 vuse = gimple_vuse (def_stmt);
2496 /* For two PHI arguments ARG0 and ARG1 try to skip non-aliasing code
2497 until we hit the phi argument definition that dominates the other one.
2498 Return that, or NULL_TREE if there is no such definition. */
2501 get_continuation_for_phi_1 (gimple *phi, tree arg0, tree arg1,
2502 ao_ref *ref, unsigned int *cnt,
2503 bitmap *visited, bool abort_on_visited,
2504 void *(*translate)(ao_ref *, tree, void *, bool *),
2507 gimple *def0 = SSA_NAME_DEF_STMT (arg0);
2508 gimple *def1 = SSA_NAME_DEF_STMT (arg1);
2513 else if (gimple_nop_p (def0)
2514 || (!gimple_nop_p (def1)
2515 && dominated_by_p (CDI_DOMINATORS,
2516 gimple_bb (def1), gimple_bb (def0))))
2518 if (maybe_skip_until (phi, arg0, ref, arg1, cnt,
2519 visited, abort_on_visited, translate, data))
2522 else if (gimple_nop_p (def1)
2523 || dominated_by_p (CDI_DOMINATORS,
2524 gimple_bb (def0), gimple_bb (def1)))
2526 if (maybe_skip_until (phi, arg1, ref, arg0, cnt,
2527 visited, abort_on_visited, translate, data))
2530 /* Special case of a diamond:
2532 goto (cond) ? L1 : L2
2533 L1: store1 = ... #MEM_2 = vuse(MEM_1)
2535 L2: store2 = ... #MEM_3 = vuse(MEM_1)
2536 L3: MEM_4 = PHI<MEM_2, MEM_3>
2537 We were called with the PHI at L3, MEM_2 and MEM_3 don't
2538 dominate each other, but still we can easily skip this PHI node
2539 if we recognize that the vuse MEM operand is the same for both,
2540 and that we can skip both statements (they don't clobber us).
2541 This is still linear. Don't use maybe_skip_until, that might
2542 potentially be slow. */
2543 else if ((common_vuse = gimple_vuse (def0))
2544 && common_vuse == gimple_vuse (def1))
2546 bool disambiguate_only = true;
2548 if ((!stmt_may_clobber_ref_p_1 (def0, ref)
2550 && (*translate) (ref, arg0, data, &disambiguate_only) == NULL))
2551 && (!stmt_may_clobber_ref_p_1 (def1, ref)
2553 && (*translate) (ref, arg1, data, &disambiguate_only) == NULL)))
2561 /* Starting from a PHI node for the virtual operand of the memory reference
2562 REF find a continuation virtual operand that allows to continue walking
2563 statements dominating PHI skipping only statements that cannot possibly
2564 clobber REF. Increments *CNT for each alias disambiguation done.
2565 Returns NULL_TREE if no suitable virtual operand can be found. */
2568 get_continuation_for_phi (gimple *phi, ao_ref *ref,
2569 unsigned int *cnt, bitmap *visited,
2570 bool abort_on_visited,
2571 void *(*translate)(ao_ref *, tree, void *, bool *),
2574 unsigned nargs = gimple_phi_num_args (phi);
2576 /* Through a single-argument PHI we can simply look through. */
2578 return PHI_ARG_DEF (phi, 0);
2580 /* For two or more arguments try to pairwise skip non-aliasing code
2581 until we hit the phi argument definition that dominates the other one. */
2582 else if (nargs >= 2)
2587 /* Find a candidate for the virtual operand which definition
2588 dominates those of all others. */
2589 arg0 = PHI_ARG_DEF (phi, 0);
2590 if (!SSA_NAME_IS_DEFAULT_DEF (arg0))
2591 for (i = 1; i < nargs; ++i)
2593 arg1 = PHI_ARG_DEF (phi, i);
2594 if (SSA_NAME_IS_DEFAULT_DEF (arg1))
2599 if (dominated_by_p (CDI_DOMINATORS,
2600 gimple_bb (SSA_NAME_DEF_STMT (arg0)),
2601 gimple_bb (SSA_NAME_DEF_STMT (arg1))))
2605 /* Then pairwise reduce against the found candidate. */
2606 for (i = 0; i < nargs; ++i)
2608 arg1 = PHI_ARG_DEF (phi, i);
2609 arg0 = get_continuation_for_phi_1 (phi, arg0, arg1, ref,
2610 cnt, visited, abort_on_visited,
2622 /* Based on the memory reference REF and its virtual use VUSE call
2623 WALKER for each virtual use that is equivalent to VUSE, including VUSE
2624 itself. That is, for each virtual use for which its defining statement
2625 does not clobber REF.
2627 WALKER is called with REF, the current virtual use and DATA. If
2628 WALKER returns non-NULL the walk stops and its result is returned.
2629 At the end of a non-successful walk NULL is returned.
2631 TRANSLATE if non-NULL is called with a pointer to REF, the virtual
2632 use which definition is a statement that may clobber REF and DATA.
2633 If TRANSLATE returns (void *)-1 the walk stops and NULL is returned.
2634 If TRANSLATE returns non-NULL the walk stops and its result is returned.
2635 If TRANSLATE returns NULL the walk continues and TRANSLATE is supposed
2636 to adjust REF and *DATA to make that valid.
2638 VALUEIZE if non-NULL is called with the next VUSE that is considered
2639 and return value is substituted for that. This can be used to
2640 implement optimistic value-numbering for example. Note that the
2641 VUSE argument is assumed to be valueized already.
2643 TODO: Cache the vector of equivalent vuses per ref, vuse pair. */
2646 walk_non_aliased_vuses (ao_ref *ref, tree vuse,
2647 void *(*walker)(ao_ref *, tree, unsigned int, void *),
2648 void *(*translate)(ao_ref *, tree, void *, bool *),
2649 tree (*valueize)(tree),
2652 bitmap visited = NULL;
2654 unsigned int cnt = 0;
2655 bool translated = false;
2657 timevar_push (TV_ALIAS_STMT_WALK);
2663 /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */
2664 res = (*walker) (ref, vuse, cnt, data);
2666 if (res == (void *)-1)
2671 /* Lookup succeeded. */
2672 else if (res != NULL)
2676 vuse = valueize (vuse);
2677 def_stmt = SSA_NAME_DEF_STMT (vuse);
2678 if (gimple_nop_p (def_stmt))
2680 else if (gimple_code (def_stmt) == GIMPLE_PHI)
2681 vuse = get_continuation_for_phi (def_stmt, ref, &cnt,
2682 &visited, translated, translate, data);
2686 if (stmt_may_clobber_ref_p_1 (def_stmt, ref))
2690 bool disambiguate_only = false;
2691 res = (*translate) (ref, vuse, data, &disambiguate_only);
2692 /* Failed lookup and translation. */
2693 if (res == (void *)-1)
2698 /* Lookup succeeded. */
2699 else if (res != NULL)
2701 /* Translation succeeded, continue walking. */
2702 translated = translated || !disambiguate_only;
2704 vuse = gimple_vuse (def_stmt);
2710 BITMAP_FREE (visited);
2712 timevar_pop (TV_ALIAS_STMT_WALK);
2718 /* Based on the memory reference REF call WALKER for each vdef which
2719 defining statement may clobber REF, starting with VDEF. If REF
2720 is NULL_TREE, each defining statement is visited.
2722 WALKER is called with REF, the current vdef and DATA. If WALKER
2723 returns true the walk is stopped, otherwise it continues.
2725 If function entry is reached, FUNCTION_ENTRY_REACHED is set to true.
2726 The pointer may be NULL and then we do not track this information.
2728 At PHI nodes walk_aliased_vdefs forks into one walk for reach
2729 PHI argument (but only one walk continues on merge points), the
2730 return value is true if any of the walks was successful.
2732 The function returns the number of statements walked. */
2735 walk_aliased_vdefs_1 (ao_ref *ref, tree vdef,
2736 bool (*walker)(ao_ref *, tree, void *), void *data,
2737 bitmap *visited, unsigned int cnt,
2738 bool *function_entry_reached)
2742 gimple *def_stmt = SSA_NAME_DEF_STMT (vdef);
2745 && !bitmap_set_bit (*visited, SSA_NAME_VERSION (vdef)))
2748 if (gimple_nop_p (def_stmt))
2750 if (function_entry_reached)
2751 *function_entry_reached = true;
2754 else if (gimple_code (def_stmt) == GIMPLE_PHI)
2758 *visited = BITMAP_ALLOC (NULL);
2759 for (i = 0; i < gimple_phi_num_args (def_stmt); ++i)
2760 cnt += walk_aliased_vdefs_1 (ref, gimple_phi_arg_def (def_stmt, i),
2761 walker, data, visited, 0,
2762 function_entry_reached);
2766 /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */
2769 || stmt_may_clobber_ref_p_1 (def_stmt, ref))
2770 && (*walker) (ref, vdef, data))
2773 vdef = gimple_vuse (def_stmt);
2779 walk_aliased_vdefs (ao_ref *ref, tree vdef,
2780 bool (*walker)(ao_ref *, tree, void *), void *data,
2782 bool *function_entry_reached)
2784 bitmap local_visited = NULL;
2787 timevar_push (TV_ALIAS_STMT_WALK);
2789 if (function_entry_reached)
2790 *function_entry_reached = false;
2792 ret = walk_aliased_vdefs_1 (ref, vdef, walker, data,
2793 visited ? visited : &local_visited, 0,
2794 function_entry_reached);
2796 BITMAP_FREE (local_visited);
2798 timevar_pop (TV_ALIAS_STMT_WALK);