1 /* Alias analysis for trees.
2 Copyright (C) 2004-2014 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"
28 #include "basic-block.h"
29 #include "timevar.h" /* for TV_ALIAS_STMT_WALK */
30 #include "langhooks.h"
33 #include "tree-pretty-print.h"
35 #include "tree-ssa-alias.h"
36 #include "internal-fn.h"
38 #include "gimple-expr.h"
41 #include "gimple-ssa.h"
42 #include "stringpool.h"
43 #include "tree-ssanames.h"
46 #include "tree-inline.h"
48 #include "alloc-pool.h"
49 #include "tree-ssa-alias.h"
50 #include "ipa-reference.h"
52 /* Broad overview of how alias analysis on gimple works:
54 Statements clobbering or using memory are linked through the
55 virtual operand factored use-def chain. The virtual operand
56 is unique per function, its symbol is accessible via gimple_vop (cfun).
57 Virtual operands are used for efficiently walking memory statements
58 in the gimple IL and are useful for things like value-numbering as
59 a generation count for memory references.
61 SSA_NAME pointers may have associated points-to information
62 accessible via the SSA_NAME_PTR_INFO macro. Flow-insensitive
63 points-to information is (re-)computed by the TODO_rebuild_alias
64 pass manager todo. Points-to information is also used for more
65 precise tracking of call-clobbered and call-used variables and
66 related disambiguations.
68 This file contains functions for disambiguating memory references,
69 the so called alias-oracle and tools for walking of the gimple IL.
71 The main alias-oracle entry-points are
73 bool stmt_may_clobber_ref_p (gimple, tree)
75 This function queries if a statement may invalidate (parts of)
76 the memory designated by the reference tree argument.
78 bool ref_maybe_used_by_stmt_p (gimple, tree)
80 This function queries if a statement may need (parts of) the
81 memory designated by the reference tree argument.
83 There are variants of these functions that only handle the call
84 part of a statement, call_may_clobber_ref_p and ref_maybe_used_by_call_p.
85 Note that these do not disambiguate against a possible call lhs.
87 bool refs_may_alias_p (tree, tree)
89 This function tries to disambiguate two reference trees.
91 bool ptr_deref_may_alias_global_p (tree)
93 This function queries if dereferencing a pointer variable may
96 More low-level disambiguators are available and documented in
97 this file. Low-level disambiguators dealing with points-to
98 information are in tree-ssa-structalias.c. */
101 /* Query statistics for the different low-level disambiguators.
102 A high-level query may trigger multiple of them. */
105 unsigned HOST_WIDE_INT refs_may_alias_p_may_alias
;
106 unsigned HOST_WIDE_INT refs_may_alias_p_no_alias
;
107 unsigned HOST_WIDE_INT ref_maybe_used_by_call_p_may_alias
;
108 unsigned HOST_WIDE_INT ref_maybe_used_by_call_p_no_alias
;
109 unsigned HOST_WIDE_INT call_may_clobber_ref_p_may_alias
;
110 unsigned HOST_WIDE_INT call_may_clobber_ref_p_no_alias
;
114 dump_alias_stats (FILE *s
)
116 fprintf (s
, "\nAlias oracle query stats:\n");
117 fprintf (s
, " refs_may_alias_p: "
118 HOST_WIDE_INT_PRINT_DEC
" disambiguations, "
119 HOST_WIDE_INT_PRINT_DEC
" queries\n",
120 alias_stats
.refs_may_alias_p_no_alias
,
121 alias_stats
.refs_may_alias_p_no_alias
122 + alias_stats
.refs_may_alias_p_may_alias
);
123 fprintf (s
, " ref_maybe_used_by_call_p: "
124 HOST_WIDE_INT_PRINT_DEC
" disambiguations, "
125 HOST_WIDE_INT_PRINT_DEC
" queries\n",
126 alias_stats
.ref_maybe_used_by_call_p_no_alias
,
127 alias_stats
.refs_may_alias_p_no_alias
128 + alias_stats
.ref_maybe_used_by_call_p_may_alias
);
129 fprintf (s
, " call_may_clobber_ref_p: "
130 HOST_WIDE_INT_PRINT_DEC
" disambiguations, "
131 HOST_WIDE_INT_PRINT_DEC
" queries\n",
132 alias_stats
.call_may_clobber_ref_p_no_alias
,
133 alias_stats
.call_may_clobber_ref_p_no_alias
134 + alias_stats
.call_may_clobber_ref_p_may_alias
);
138 /* Return true, if dereferencing PTR may alias with a global variable. */
141 ptr_deref_may_alias_global_p (tree ptr
)
143 struct ptr_info_def
*pi
;
145 /* If we end up with a pointer constant here that may point
147 if (TREE_CODE (ptr
) != SSA_NAME
)
150 pi
= SSA_NAME_PTR_INFO (ptr
);
152 /* If we do not have points-to information for this variable,
157 /* ??? This does not use TBAA to prune globals ptr may not access. */
158 return pt_solution_includes_global (&pi
->pt
);
161 /* Return true if dereferencing PTR may alias DECL.
162 The caller is responsible for applying TBAA to see if PTR
163 may access DECL at all. */
166 ptr_deref_may_alias_decl_p (tree ptr
, tree decl
)
168 struct ptr_info_def
*pi
;
170 /* Conversions are irrelevant for points-to information and
171 data-dependence analysis can feed us those. */
174 /* Anything we do not explicilty handle aliases. */
175 if ((TREE_CODE (ptr
) != SSA_NAME
176 && TREE_CODE (ptr
) != ADDR_EXPR
177 && TREE_CODE (ptr
) != POINTER_PLUS_EXPR
)
178 || !POINTER_TYPE_P (TREE_TYPE (ptr
))
179 || (TREE_CODE (decl
) != VAR_DECL
180 && TREE_CODE (decl
) != PARM_DECL
181 && TREE_CODE (decl
) != RESULT_DECL
))
184 /* Disregard pointer offsetting. */
185 if (TREE_CODE (ptr
) == POINTER_PLUS_EXPR
)
189 ptr
= TREE_OPERAND (ptr
, 0);
191 while (TREE_CODE (ptr
) == POINTER_PLUS_EXPR
);
192 return ptr_deref_may_alias_decl_p (ptr
, decl
);
195 /* ADDR_EXPR pointers either just offset another pointer or directly
196 specify the pointed-to set. */
197 if (TREE_CODE (ptr
) == ADDR_EXPR
)
199 tree base
= get_base_address (TREE_OPERAND (ptr
, 0));
201 && (TREE_CODE (base
) == MEM_REF
202 || TREE_CODE (base
) == TARGET_MEM_REF
))
203 ptr
= TREE_OPERAND (base
, 0);
208 && CONSTANT_CLASS_P (base
))
214 /* Non-aliased variables can not be pointed to. */
215 if (!may_be_aliased (decl
))
218 /* If we do not have useful points-to information for this pointer
219 we cannot disambiguate anything else. */
220 pi
= SSA_NAME_PTR_INFO (ptr
);
224 return pt_solution_includes (&pi
->pt
, decl
);
227 /* Return true if dereferenced PTR1 and PTR2 may alias.
228 The caller is responsible for applying TBAA to see if accesses
229 through PTR1 and PTR2 may conflict at all. */
232 ptr_derefs_may_alias_p (tree ptr1
, tree ptr2
)
234 struct ptr_info_def
*pi1
, *pi2
;
236 /* Conversions are irrelevant for points-to information and
237 data-dependence analysis can feed us those. */
241 /* Disregard pointer offsetting. */
242 if (TREE_CODE (ptr1
) == POINTER_PLUS_EXPR
)
246 ptr1
= TREE_OPERAND (ptr1
, 0);
248 while (TREE_CODE (ptr1
) == POINTER_PLUS_EXPR
);
249 return ptr_derefs_may_alias_p (ptr1
, ptr2
);
251 if (TREE_CODE (ptr2
) == POINTER_PLUS_EXPR
)
255 ptr2
= TREE_OPERAND (ptr2
, 0);
257 while (TREE_CODE (ptr2
) == POINTER_PLUS_EXPR
);
258 return ptr_derefs_may_alias_p (ptr1
, ptr2
);
261 /* ADDR_EXPR pointers either just offset another pointer or directly
262 specify the pointed-to set. */
263 if (TREE_CODE (ptr1
) == ADDR_EXPR
)
265 tree base
= get_base_address (TREE_OPERAND (ptr1
, 0));
267 && (TREE_CODE (base
) == MEM_REF
268 || TREE_CODE (base
) == TARGET_MEM_REF
))
269 return ptr_derefs_may_alias_p (TREE_OPERAND (base
, 0), ptr2
);
272 return ptr_deref_may_alias_decl_p (ptr2
, base
);
276 if (TREE_CODE (ptr2
) == ADDR_EXPR
)
278 tree base
= get_base_address (TREE_OPERAND (ptr2
, 0));
280 && (TREE_CODE (base
) == MEM_REF
281 || TREE_CODE (base
) == TARGET_MEM_REF
))
282 return ptr_derefs_may_alias_p (ptr1
, TREE_OPERAND (base
, 0));
285 return ptr_deref_may_alias_decl_p (ptr1
, base
);
290 /* From here we require SSA name pointers. Anything else aliases. */
291 if (TREE_CODE (ptr1
) != SSA_NAME
292 || TREE_CODE (ptr2
) != SSA_NAME
293 || !POINTER_TYPE_P (TREE_TYPE (ptr1
))
294 || !POINTER_TYPE_P (TREE_TYPE (ptr2
)))
297 /* We may end up with two empty points-to solutions for two same pointers.
298 In this case we still want to say both pointers alias, so shortcut
303 /* If we do not have useful points-to information for either pointer
304 we cannot disambiguate anything else. */
305 pi1
= SSA_NAME_PTR_INFO (ptr1
);
306 pi2
= SSA_NAME_PTR_INFO (ptr2
);
310 /* ??? This does not use TBAA to prune decls from the intersection
311 that not both pointers may access. */
312 return pt_solutions_intersect (&pi1
->pt
, &pi2
->pt
);
315 /* Return true if dereferencing PTR may alias *REF.
316 The caller is responsible for applying TBAA to see if PTR
317 may access *REF at all. */
320 ptr_deref_may_alias_ref_p_1 (tree ptr
, ao_ref
*ref
)
322 tree base
= ao_ref_base (ref
);
324 if (TREE_CODE (base
) == MEM_REF
325 || TREE_CODE (base
) == TARGET_MEM_REF
)
326 return ptr_derefs_may_alias_p (ptr
, TREE_OPERAND (base
, 0));
327 else if (DECL_P (base
))
328 return ptr_deref_may_alias_decl_p (ptr
, base
);
333 /* Return true whether REF may refer to global memory. */
336 ref_may_alias_global_p (tree ref
)
338 tree base
= get_base_address (ref
);
340 return is_global_var (base
);
341 else if (TREE_CODE (base
) == MEM_REF
342 || TREE_CODE (base
) == TARGET_MEM_REF
)
343 return ptr_deref_may_alias_global_p (TREE_OPERAND (base
, 0));
347 /* Return true whether STMT may clobber global memory. */
350 stmt_may_clobber_global_p (gimple stmt
)
354 if (!gimple_vdef (stmt
))
357 /* ??? We can ask the oracle whether an artificial pointer
358 dereference with a pointer with points-to information covering
359 all global memory (what about non-address taken memory?) maybe
360 clobbered by this call. As there is at the moment no convenient
361 way of doing that without generating garbage do some manual
363 ??? We could make a NULL ao_ref argument to the various
364 predicates special, meaning any global memory. */
366 switch (gimple_code (stmt
))
369 lhs
= gimple_assign_lhs (stmt
);
370 return (TREE_CODE (lhs
) != SSA_NAME
371 && ref_may_alias_global_p (lhs
));
380 /* Dump alias information on FILE. */
383 dump_alias_info (FILE *file
)
387 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
390 fprintf (file
, "\n\nAlias information for %s\n\n", funcname
);
392 fprintf (file
, "Aliased symbols\n\n");
394 FOR_EACH_LOCAL_DECL (cfun
, i
, var
)
396 if (may_be_aliased (var
))
397 dump_variable (file
, var
);
400 fprintf (file
, "\nCall clobber information\n");
402 fprintf (file
, "\nESCAPED");
403 dump_points_to_solution (file
, &cfun
->gimple_df
->escaped
);
405 fprintf (file
, "\n\nFlow-insensitive points-to information\n\n");
407 for (i
= 1; i
< num_ssa_names
; i
++)
409 tree ptr
= ssa_name (i
);
410 struct ptr_info_def
*pi
;
413 || !POINTER_TYPE_P (TREE_TYPE (ptr
))
414 || SSA_NAME_IN_FREE_LIST (ptr
))
417 pi
= SSA_NAME_PTR_INFO (ptr
);
419 dump_points_to_info_for (file
, ptr
);
422 fprintf (file
, "\n");
426 /* Dump alias information on stderr. */
429 debug_alias_info (void)
431 dump_alias_info (stderr
);
435 /* Dump the points-to set *PT into FILE. */
438 dump_points_to_solution (FILE *file
, struct pt_solution
*pt
)
441 fprintf (file
, ", points-to anything");
444 fprintf (file
, ", points-to non-local");
447 fprintf (file
, ", points-to escaped");
450 fprintf (file
, ", points-to unit escaped");
453 fprintf (file
, ", points-to NULL");
457 fprintf (file
, ", points-to vars: ");
458 dump_decl_set (file
, pt
->vars
);
459 if (pt
->vars_contains_nonlocal
460 && pt
->vars_contains_escaped_heap
)
461 fprintf (file
, " (nonlocal, escaped heap)");
462 else if (pt
->vars_contains_nonlocal
463 && pt
->vars_contains_escaped
)
464 fprintf (file
, " (nonlocal, escaped)");
465 else if (pt
->vars_contains_nonlocal
)
466 fprintf (file
, " (nonlocal)");
467 else if (pt
->vars_contains_escaped_heap
)
468 fprintf (file
, " (escaped heap)");
469 else if (pt
->vars_contains_escaped
)
470 fprintf (file
, " (escaped)");
475 /* Unified dump function for pt_solution. */
478 debug (pt_solution
&ref
)
480 dump_points_to_solution (stderr
, &ref
);
484 debug (pt_solution
*ptr
)
489 fprintf (stderr
, "<nil>\n");
493 /* Dump points-to information for SSA_NAME PTR into FILE. */
496 dump_points_to_info_for (FILE *file
, tree ptr
)
498 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (ptr
);
500 print_generic_expr (file
, ptr
, dump_flags
);
503 dump_points_to_solution (file
, &pi
->pt
);
505 fprintf (file
, ", points-to anything");
507 fprintf (file
, "\n");
511 /* Dump points-to information for VAR into stderr. */
514 debug_points_to_info_for (tree var
)
516 dump_points_to_info_for (stderr
, var
);
520 /* Initializes the alias-oracle reference representation *R from REF. */
523 ao_ref_init (ao_ref
*r
, tree ref
)
530 r
->ref_alias_set
= -1;
531 r
->base_alias_set
= -1;
532 r
->volatile_p
= ref
? TREE_THIS_VOLATILE (ref
) : false;
535 /* Returns the base object of the memory reference *REF. */
538 ao_ref_base (ao_ref
*ref
)
542 ref
->base
= get_ref_base_and_extent (ref
->ref
, &ref
->offset
, &ref
->size
,
547 /* Returns the base object alias set of the memory reference *REF. */
549 static alias_set_type
550 ao_ref_base_alias_set (ao_ref
*ref
)
553 if (ref
->base_alias_set
!= -1)
554 return ref
->base_alias_set
;
558 while (handled_component_p (base_ref
))
559 base_ref
= TREE_OPERAND (base_ref
, 0);
560 ref
->base_alias_set
= get_alias_set (base_ref
);
561 return ref
->base_alias_set
;
564 /* Returns the reference alias set of the memory reference *REF. */
567 ao_ref_alias_set (ao_ref
*ref
)
569 if (ref
->ref_alias_set
!= -1)
570 return ref
->ref_alias_set
;
571 ref
->ref_alias_set
= get_alias_set (ref
->ref
);
572 return ref
->ref_alias_set
;
575 /* Init an alias-oracle reference representation from a gimple pointer
576 PTR and a gimple size SIZE in bytes. If SIZE is NULL_TREE then the
577 size is assumed to be unknown. The access is assumed to be only
578 to or after of the pointer target, not before it. */
581 ao_ref_init_from_ptr_and_size (ao_ref
*ref
, tree ptr
, tree size
)
583 HOST_WIDE_INT t
, size_hwi
, extra_offset
= 0;
584 ref
->ref
= NULL_TREE
;
585 if (TREE_CODE (ptr
) == SSA_NAME
)
587 gimple stmt
= SSA_NAME_DEF_STMT (ptr
);
588 if (gimple_assign_single_p (stmt
)
589 && gimple_assign_rhs_code (stmt
) == ADDR_EXPR
)
590 ptr
= gimple_assign_rhs1 (stmt
);
591 else if (is_gimple_assign (stmt
)
592 && gimple_assign_rhs_code (stmt
) == POINTER_PLUS_EXPR
593 && TREE_CODE (gimple_assign_rhs2 (stmt
)) == INTEGER_CST
)
595 ptr
= gimple_assign_rhs1 (stmt
);
596 extra_offset
= BITS_PER_UNIT
597 * int_cst_value (gimple_assign_rhs2 (stmt
));
601 if (TREE_CODE (ptr
) == ADDR_EXPR
)
603 ref
->base
= get_addr_base_and_unit_offset (TREE_OPERAND (ptr
, 0), &t
);
605 ref
->offset
= BITS_PER_UNIT
* t
;
610 ref
->base
= get_base_address (TREE_OPERAND (ptr
, 0));
615 ref
->base
= build2 (MEM_REF
, char_type_node
,
616 ptr
, null_pointer_node
);
619 ref
->offset
+= extra_offset
;
621 && tree_fits_shwi_p (size
)
622 && (size_hwi
= tree_to_shwi (size
)) <= HOST_WIDE_INT_MAX
/ BITS_PER_UNIT
)
623 ref
->max_size
= ref
->size
= size_hwi
* BITS_PER_UNIT
;
625 ref
->max_size
= ref
->size
= -1;
626 ref
->ref_alias_set
= 0;
627 ref
->base_alias_set
= 0;
628 ref
->volatile_p
= false;
631 /* Return 1 if TYPE1 and TYPE2 are to be considered equivalent for the
632 purpose of TBAA. Return 0 if they are distinct and -1 if we cannot
636 same_type_for_tbaa (tree type1
, tree type2
)
638 type1
= TYPE_MAIN_VARIANT (type1
);
639 type2
= TYPE_MAIN_VARIANT (type2
);
641 /* If we would have to do structural comparison bail out. */
642 if (TYPE_STRUCTURAL_EQUALITY_P (type1
)
643 || TYPE_STRUCTURAL_EQUALITY_P (type2
))
646 /* Compare the canonical types. */
647 if (TYPE_CANONICAL (type1
) == TYPE_CANONICAL (type2
))
650 /* ??? Array types are not properly unified in all cases as we have
651 spurious changes in the index types for example. Removing this
652 causes all sorts of problems with the Fortran frontend. */
653 if (TREE_CODE (type1
) == ARRAY_TYPE
654 && TREE_CODE (type2
) == ARRAY_TYPE
)
657 /* ??? In Ada, an lvalue of an unconstrained type can be used to access an
658 object of one of its constrained subtypes, e.g. when a function with an
659 unconstrained parameter passed by reference is called on an object and
660 inlined. But, even in the case of a fixed size, type and subtypes are
661 not equivalent enough as to share the same TYPE_CANONICAL, since this
662 would mean that conversions between them are useless, whereas they are
663 not (e.g. type and subtypes can have different modes). So, in the end,
664 they are only guaranteed to have the same alias set. */
665 if (get_alias_set (type1
) == get_alias_set (type2
))
668 /* The types are known to be not equal. */
672 /* Determine if the two component references REF1 and REF2 which are
673 based on access types TYPE1 and TYPE2 and of which at least one is based
674 on an indirect reference may alias. REF2 is the only one that can
675 be a decl in which case REF2_IS_DECL is true.
676 REF1_ALIAS_SET, BASE1_ALIAS_SET, REF2_ALIAS_SET and BASE2_ALIAS_SET
677 are the respective alias sets. */
680 aliasing_component_refs_p (tree ref1
,
681 alias_set_type ref1_alias_set
,
682 alias_set_type base1_alias_set
,
683 HOST_WIDE_INT offset1
, HOST_WIDE_INT max_size1
,
685 alias_set_type ref2_alias_set
,
686 alias_set_type base2_alias_set
,
687 HOST_WIDE_INT offset2
, HOST_WIDE_INT max_size2
,
690 /* If one reference is a component references through pointers try to find a
691 common base and apply offset based disambiguation. This handles
693 struct A { int i; int j; } *q;
694 struct B { struct A a; int k; } *p;
695 disambiguating q->i and p->a.j. */
701 /* Choose bases and base types to search for. */
703 while (handled_component_p (base1
))
704 base1
= TREE_OPERAND (base1
, 0);
705 type1
= TREE_TYPE (base1
);
707 while (handled_component_p (base2
))
708 base2
= TREE_OPERAND (base2
, 0);
709 type2
= TREE_TYPE (base2
);
711 /* Now search for the type1 in the access path of ref2. This
712 would be a common base for doing offset based disambiguation on. */
714 while (handled_component_p (*refp
)
715 && same_type_for_tbaa (TREE_TYPE (*refp
), type1
) == 0)
716 refp
= &TREE_OPERAND (*refp
, 0);
717 same_p
= same_type_for_tbaa (TREE_TYPE (*refp
), type1
);
718 /* If we couldn't compare types we have to bail out. */
721 else if (same_p
== 1)
723 HOST_WIDE_INT offadj
, sztmp
, msztmp
;
724 get_ref_base_and_extent (*refp
, &offadj
, &sztmp
, &msztmp
);
726 get_ref_base_and_extent (base1
, &offadj
, &sztmp
, &msztmp
);
728 return ranges_overlap_p (offset1
, max_size1
, offset2
, max_size2
);
730 /* If we didn't find a common base, try the other way around. */
732 while (handled_component_p (*refp
)
733 && same_type_for_tbaa (TREE_TYPE (*refp
), type2
) == 0)
734 refp
= &TREE_OPERAND (*refp
, 0);
735 same_p
= same_type_for_tbaa (TREE_TYPE (*refp
), type2
);
736 /* If we couldn't compare types we have to bail out. */
739 else if (same_p
== 1)
741 HOST_WIDE_INT offadj
, sztmp
, msztmp
;
742 get_ref_base_and_extent (*refp
, &offadj
, &sztmp
, &msztmp
);
744 get_ref_base_and_extent (base2
, &offadj
, &sztmp
, &msztmp
);
746 return ranges_overlap_p (offset1
, max_size1
, offset2
, max_size2
);
749 /* If we have two type access paths B1.path1 and B2.path2 they may
750 only alias if either B1 is in B2.path2 or B2 is in B1.path1.
751 But we can still have a path that goes B1.path1...B2.path2 with
752 a part that we do not see. So we can only disambiguate now
753 if there is no B2 in the tail of path1 and no B1 on the
755 if (base1_alias_set
== ref2_alias_set
756 || alias_set_subset_of (base1_alias_set
, ref2_alias_set
))
758 /* If this is ptr vs. decl then we know there is no ptr ... decl path. */
760 return (base2_alias_set
== ref1_alias_set
761 || alias_set_subset_of (base2_alias_set
, ref1_alias_set
));
765 /* Return true if we can determine that component references REF1 and REF2,
766 that are within a common DECL, cannot overlap. */
769 nonoverlapping_component_refs_of_decl_p (tree ref1
, tree ref2
)
771 auto_vec
<tree
, 16> component_refs1
;
772 auto_vec
<tree
, 16> component_refs2
;
774 /* Create the stack of handled components for REF1. */
775 while (handled_component_p (ref1
))
777 component_refs1
.safe_push (ref1
);
778 ref1
= TREE_OPERAND (ref1
, 0);
780 if (TREE_CODE (ref1
) == MEM_REF
)
782 if (!integer_zerop (TREE_OPERAND (ref1
, 1)))
784 ref1
= TREE_OPERAND (TREE_OPERAND (ref1
, 0), 0);
787 /* Create the stack of handled components for REF2. */
788 while (handled_component_p (ref2
))
790 component_refs2
.safe_push (ref2
);
791 ref2
= TREE_OPERAND (ref2
, 0);
793 if (TREE_CODE (ref2
) == MEM_REF
)
795 if (!integer_zerop (TREE_OPERAND (ref2
, 1)))
797 ref2
= TREE_OPERAND (TREE_OPERAND (ref2
, 0), 0);
800 /* We must have the same base DECL. */
801 gcc_assert (ref1
== ref2
);
803 /* Pop the stacks in parallel and examine the COMPONENT_REFs of the same
804 rank. This is sufficient because we start from the same DECL and you
805 cannot reference several fields at a time with COMPONENT_REFs (unlike
806 with ARRAY_RANGE_REFs for arrays) so you always need the same number
807 of them to access a sub-component, unless you're in a union, in which
808 case the return value will precisely be false. */
813 if (component_refs1
.is_empty ())
815 ref1
= component_refs1
.pop ();
817 while (!RECORD_OR_UNION_TYPE_P (TREE_TYPE (TREE_OPERAND (ref1
, 0))));
821 if (component_refs2
.is_empty ())
823 ref2
= component_refs2
.pop ();
825 while (!RECORD_OR_UNION_TYPE_P (TREE_TYPE (TREE_OPERAND (ref2
, 0))));
827 /* Beware of BIT_FIELD_REF. */
828 if (TREE_CODE (ref1
) != COMPONENT_REF
829 || TREE_CODE (ref2
) != COMPONENT_REF
)
832 tree field1
= TREE_OPERAND (ref1
, 1);
833 tree field2
= TREE_OPERAND (ref2
, 1);
835 /* ??? We cannot simply use the type of operand #0 of the refs here
836 as the Fortran compiler smuggles type punning into COMPONENT_REFs
837 for common blocks instead of using unions like everyone else. */
838 tree type1
= TYPE_MAIN_VARIANT (DECL_CONTEXT (field1
));
839 tree type2
= TYPE_MAIN_VARIANT (DECL_CONTEXT (field2
));
841 /* We cannot disambiguate fields in a union or qualified union. */
842 if (type1
!= type2
|| TREE_CODE (type1
) != RECORD_TYPE
)
845 /* Different fields of the same record type cannot overlap.
846 ??? Bitfields can overlap at RTL level so punt on them. */
847 if (field1
!= field2
)
849 component_refs1
.release ();
850 component_refs2
.release ();
851 return !(DECL_BIT_FIELD (field1
) && DECL_BIT_FIELD (field2
));
856 component_refs1
.release ();
857 component_refs2
.release ();
861 /* Return true if two memory references based on the variables BASE1
862 and BASE2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and
863 [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. REF1 and REF2
864 if non-NULL are the complete memory reference trees. */
867 decl_refs_may_alias_p (tree ref1
, tree base1
,
868 HOST_WIDE_INT offset1
, HOST_WIDE_INT max_size1
,
869 tree ref2
, tree base2
,
870 HOST_WIDE_INT offset2
, HOST_WIDE_INT max_size2
)
872 gcc_checking_assert (DECL_P (base1
) && DECL_P (base2
));
874 /* If both references are based on different variables, they cannot alias. */
878 /* If both references are based on the same variable, they cannot alias if
879 the accesses do not overlap. */
880 if (!ranges_overlap_p (offset1
, max_size1
, offset2
, max_size2
))
883 /* For components with variable position, the above test isn't sufficient,
884 so we disambiguate component references manually. */
886 && handled_component_p (ref1
) && handled_component_p (ref2
)
887 && nonoverlapping_component_refs_of_decl_p (ref1
, ref2
))
893 /* Return true if an indirect reference based on *PTR1 constrained
894 to [OFFSET1, OFFSET1 + MAX_SIZE1) may alias a variable based on BASE2
895 constrained to [OFFSET2, OFFSET2 + MAX_SIZE2). *PTR1 and BASE2 have
896 the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1
897 in which case they are computed on-demand. REF1 and REF2
898 if non-NULL are the complete memory reference trees. */
901 indirect_ref_may_alias_decl_p (tree ref1 ATTRIBUTE_UNUSED
, tree base1
,
902 HOST_WIDE_INT offset1
,
903 HOST_WIDE_INT max_size1 ATTRIBUTE_UNUSED
,
904 alias_set_type ref1_alias_set
,
905 alias_set_type base1_alias_set
,
906 tree ref2 ATTRIBUTE_UNUSED
, tree base2
,
907 HOST_WIDE_INT offset2
, HOST_WIDE_INT max_size2
,
908 alias_set_type ref2_alias_set
,
909 alias_set_type base2_alias_set
, bool tbaa_p
)
912 tree ptrtype1
, dbase2
;
913 HOST_WIDE_INT offset1p
= offset1
, offset2p
= offset2
;
914 HOST_WIDE_INT doffset1
, doffset2
;
916 gcc_checking_assert ((TREE_CODE (base1
) == MEM_REF
917 || TREE_CODE (base1
) == TARGET_MEM_REF
)
920 ptr1
= TREE_OPERAND (base1
, 0);
922 /* The offset embedded in MEM_REFs can be negative. Bias them
923 so that the resulting offset adjustment is positive. */
924 offset_int moff
= mem_ref_offset (base1
);
925 moff
= wi::lshift (moff
, (BITS_PER_UNIT
== 8
926 ? 3 : exact_log2 (BITS_PER_UNIT
)));
927 if (wi::neg_p (moff
))
928 offset2p
+= (-moff
).to_short_addr ();
930 offset1p
+= moff
.to_short_addr ();
932 /* If only one reference is based on a variable, they cannot alias if
933 the pointer access is beyond the extent of the variable access.
934 (the pointer base cannot validly point to an offset less than zero
936 ??? IVOPTs creates bases that do not honor this restriction,
937 so do not apply this optimization for TARGET_MEM_REFs. */
938 if (TREE_CODE (base1
) != TARGET_MEM_REF
939 && !ranges_overlap_p (MAX (0, offset1p
), -1, offset2p
, max_size2
))
941 /* They also cannot alias if the pointer may not point to the decl. */
942 if (!ptr_deref_may_alias_decl_p (ptr1
, base2
))
945 /* Disambiguations that rely on strict aliasing rules follow. */
946 if (!flag_strict_aliasing
|| !tbaa_p
)
949 ptrtype1
= TREE_TYPE (TREE_OPERAND (base1
, 1));
951 /* If the alias set for a pointer access is zero all bets are off. */
952 if (base1_alias_set
== -1)
953 base1_alias_set
= get_deref_alias_set (ptrtype1
);
954 if (base1_alias_set
== 0)
956 if (base2_alias_set
== -1)
957 base2_alias_set
= get_alias_set (base2
);
959 /* When we are trying to disambiguate an access with a pointer dereference
960 as base versus one with a decl as base we can use both the size
961 of the decl and its dynamic type for extra disambiguation.
962 ??? We do not know anything about the dynamic type of the decl
963 other than that its alias-set contains base2_alias_set as a subset
964 which does not help us here. */
965 /* As we know nothing useful about the dynamic type of the decl just
966 use the usual conflict check rather than a subset test.
967 ??? We could introduce -fvery-strict-aliasing when the language
968 does not allow decls to have a dynamic type that differs from their
969 static type. Then we can check
970 !alias_set_subset_of (base1_alias_set, base2_alias_set) instead. */
971 if (base1_alias_set
!= base2_alias_set
972 && !alias_sets_conflict_p (base1_alias_set
, base2_alias_set
))
974 /* If the size of the access relevant for TBAA through the pointer
975 is bigger than the size of the decl we can't possibly access the
976 decl via that pointer. */
977 if (DECL_SIZE (base2
) && COMPLETE_TYPE_P (TREE_TYPE (ptrtype1
))
978 && TREE_CODE (DECL_SIZE (base2
)) == INTEGER_CST
979 && TREE_CODE (TYPE_SIZE (TREE_TYPE (ptrtype1
))) == INTEGER_CST
980 /* ??? This in turn may run afoul when a decl of type T which is
981 a member of union type U is accessed through a pointer to
982 type U and sizeof T is smaller than sizeof U. */
983 && TREE_CODE (TREE_TYPE (ptrtype1
)) != UNION_TYPE
984 && TREE_CODE (TREE_TYPE (ptrtype1
)) != QUAL_UNION_TYPE
985 && tree_int_cst_lt (DECL_SIZE (base2
), TYPE_SIZE (TREE_TYPE (ptrtype1
))))
991 /* If the decl is accessed via a MEM_REF, reconstruct the base
992 we can use for TBAA and an appropriately adjusted offset. */
994 while (handled_component_p (dbase2
))
995 dbase2
= TREE_OPERAND (dbase2
, 0);
998 if (TREE_CODE (dbase2
) == MEM_REF
999 || TREE_CODE (dbase2
) == TARGET_MEM_REF
)
1001 offset_int moff
= mem_ref_offset (dbase2
);
1002 moff
= wi::lshift (moff
, (BITS_PER_UNIT
== 8
1003 ? 3 : exact_log2 (BITS_PER_UNIT
)));
1004 if (wi::neg_p (moff
))
1005 doffset1
-= (-moff
).to_short_addr ();
1007 doffset2
-= moff
.to_short_addr ();
1010 /* If either reference is view-converted, give up now. */
1011 if (same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (ptrtype1
)) != 1
1012 || same_type_for_tbaa (TREE_TYPE (dbase2
), TREE_TYPE (base2
)) != 1)
1015 /* If both references are through the same type, they do not alias
1016 if the accesses do not overlap. This does extra disambiguation
1017 for mixed/pointer accesses but requires strict aliasing.
1018 For MEM_REFs we require that the component-ref offset we computed
1019 is relative to the start of the type which we ensure by
1020 comparing rvalue and access type and disregarding the constant
1022 if ((TREE_CODE (base1
) != TARGET_MEM_REF
1023 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1024 && same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (dbase2
)) == 1)
1025 return ranges_overlap_p (doffset1
, max_size1
, doffset2
, max_size2
);
1027 /* Do access-path based disambiguation. */
1029 && (handled_component_p (ref1
) || handled_component_p (ref2
)))
1030 return aliasing_component_refs_p (ref1
,
1031 ref1_alias_set
, base1_alias_set
,
1034 ref2_alias_set
, base2_alias_set
,
1035 offset2
, max_size2
, true);
1040 /* Return true if two indirect references based on *PTR1
1041 and *PTR2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and
1042 [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. *PTR1 and *PTR2 have
1043 the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1
1044 in which case they are computed on-demand. REF1 and REF2
1045 if non-NULL are the complete memory reference trees. */
1048 indirect_refs_may_alias_p (tree ref1 ATTRIBUTE_UNUSED
, tree base1
,
1049 HOST_WIDE_INT offset1
, HOST_WIDE_INT max_size1
,
1050 alias_set_type ref1_alias_set
,
1051 alias_set_type base1_alias_set
,
1052 tree ref2 ATTRIBUTE_UNUSED
, tree base2
,
1053 HOST_WIDE_INT offset2
, HOST_WIDE_INT max_size2
,
1054 alias_set_type ref2_alias_set
,
1055 alias_set_type base2_alias_set
, bool tbaa_p
)
1059 tree ptrtype1
, ptrtype2
;
1061 gcc_checking_assert ((TREE_CODE (base1
) == MEM_REF
1062 || TREE_CODE (base1
) == TARGET_MEM_REF
)
1063 && (TREE_CODE (base2
) == MEM_REF
1064 || TREE_CODE (base2
) == TARGET_MEM_REF
));
1066 ptr1
= TREE_OPERAND (base1
, 0);
1067 ptr2
= TREE_OPERAND (base2
, 0);
1069 /* If both bases are based on pointers they cannot alias if they may not
1070 point to the same memory object or if they point to the same object
1071 and the accesses do not overlap. */
1072 if ((!cfun
|| gimple_in_ssa_p (cfun
))
1073 && operand_equal_p (ptr1
, ptr2
, 0)
1074 && (((TREE_CODE (base1
) != TARGET_MEM_REF
1075 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1076 && (TREE_CODE (base2
) != TARGET_MEM_REF
1077 || (!TMR_INDEX (base2
) && !TMR_INDEX2 (base2
))))
1078 || (TREE_CODE (base1
) == TARGET_MEM_REF
1079 && TREE_CODE (base2
) == TARGET_MEM_REF
1080 && (TMR_STEP (base1
) == TMR_STEP (base2
)
1081 || (TMR_STEP (base1
) && TMR_STEP (base2
)
1082 && operand_equal_p (TMR_STEP (base1
),
1083 TMR_STEP (base2
), 0)))
1084 && (TMR_INDEX (base1
) == TMR_INDEX (base2
)
1085 || (TMR_INDEX (base1
) && TMR_INDEX (base2
)
1086 && operand_equal_p (TMR_INDEX (base1
),
1087 TMR_INDEX (base2
), 0)))
1088 && (TMR_INDEX2 (base1
) == TMR_INDEX2 (base2
)
1089 || (TMR_INDEX2 (base1
) && TMR_INDEX2 (base2
)
1090 && operand_equal_p (TMR_INDEX2 (base1
),
1091 TMR_INDEX2 (base2
), 0))))))
1094 /* The offset embedded in MEM_REFs can be negative. Bias them
1095 so that the resulting offset adjustment is positive. */
1096 moff
= mem_ref_offset (base1
);
1097 moff
= wi::lshift (moff
, (BITS_PER_UNIT
== 8
1098 ? 3 : exact_log2 (BITS_PER_UNIT
)));
1099 if (wi::neg_p (moff
))
1100 offset2
+= (-moff
).to_short_addr ();
1102 offset1
+= moff
.to_shwi ();
1103 moff
= mem_ref_offset (base2
);
1104 moff
= wi::lshift (moff
, (BITS_PER_UNIT
== 8
1105 ? 3 : exact_log2 (BITS_PER_UNIT
)));
1106 if (wi::neg_p (moff
))
1107 offset1
+= (-moff
).to_short_addr ();
1109 offset2
+= moff
.to_short_addr ();
1110 return ranges_overlap_p (offset1
, max_size1
, offset2
, max_size2
);
1112 if (!ptr_derefs_may_alias_p (ptr1
, ptr2
))
1115 /* Disambiguations that rely on strict aliasing rules follow. */
1116 if (!flag_strict_aliasing
|| !tbaa_p
)
1119 ptrtype1
= TREE_TYPE (TREE_OPERAND (base1
, 1));
1120 ptrtype2
= TREE_TYPE (TREE_OPERAND (base2
, 1));
1122 /* If the alias set for a pointer access is zero all bets are off. */
1123 if (base1_alias_set
== -1)
1124 base1_alias_set
= get_deref_alias_set (ptrtype1
);
1125 if (base1_alias_set
== 0)
1127 if (base2_alias_set
== -1)
1128 base2_alias_set
= get_deref_alias_set (ptrtype2
);
1129 if (base2_alias_set
== 0)
1132 /* If both references are through the same type, they do not alias
1133 if the accesses do not overlap. This does extra disambiguation
1134 for mixed/pointer accesses but requires strict aliasing. */
1135 if ((TREE_CODE (base1
) != TARGET_MEM_REF
1136 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1137 && (TREE_CODE (base2
) != TARGET_MEM_REF
1138 || (!TMR_INDEX (base2
) && !TMR_INDEX2 (base2
)))
1139 && same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (ptrtype1
)) == 1
1140 && same_type_for_tbaa (TREE_TYPE (base2
), TREE_TYPE (ptrtype2
)) == 1
1141 && same_type_for_tbaa (TREE_TYPE (ptrtype1
),
1142 TREE_TYPE (ptrtype2
)) == 1)
1143 return ranges_overlap_p (offset1
, max_size1
, offset2
, max_size2
);
1145 /* Do type-based disambiguation. */
1146 if (base1_alias_set
!= base2_alias_set
1147 && !alias_sets_conflict_p (base1_alias_set
, base2_alias_set
))
1150 /* Do access-path based disambiguation. */
1152 && (handled_component_p (ref1
) || handled_component_p (ref2
))
1153 && same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (ptrtype1
)) == 1
1154 && same_type_for_tbaa (TREE_TYPE (base2
), TREE_TYPE (ptrtype2
)) == 1)
1155 return aliasing_component_refs_p (ref1
,
1156 ref1_alias_set
, base1_alias_set
,
1159 ref2_alias_set
, base2_alias_set
,
1160 offset2
, max_size2
, false);
1165 /* Return true, if the two memory references REF1 and REF2 may alias. */
1168 refs_may_alias_p_1 (ao_ref
*ref1
, ao_ref
*ref2
, bool tbaa_p
)
1171 HOST_WIDE_INT offset1
= 0, offset2
= 0;
1172 HOST_WIDE_INT max_size1
= -1, max_size2
= -1;
1173 bool var1_p
, var2_p
, ind1_p
, ind2_p
;
1175 gcc_checking_assert ((!ref1
->ref
1176 || TREE_CODE (ref1
->ref
) == SSA_NAME
1177 || DECL_P (ref1
->ref
)
1178 || TREE_CODE (ref1
->ref
) == STRING_CST
1179 || handled_component_p (ref1
->ref
)
1180 || TREE_CODE (ref1
->ref
) == MEM_REF
1181 || TREE_CODE (ref1
->ref
) == TARGET_MEM_REF
)
1183 || TREE_CODE (ref2
->ref
) == SSA_NAME
1184 || DECL_P (ref2
->ref
)
1185 || TREE_CODE (ref2
->ref
) == STRING_CST
1186 || handled_component_p (ref2
->ref
)
1187 || TREE_CODE (ref2
->ref
) == MEM_REF
1188 || TREE_CODE (ref2
->ref
) == TARGET_MEM_REF
));
1190 /* Decompose the references into their base objects and the access. */
1191 base1
= ao_ref_base (ref1
);
1192 offset1
= ref1
->offset
;
1193 max_size1
= ref1
->max_size
;
1194 base2
= ao_ref_base (ref2
);
1195 offset2
= ref2
->offset
;
1196 max_size2
= ref2
->max_size
;
1198 /* We can end up with registers or constants as bases for example from
1199 *D.1663_44 = VIEW_CONVERT_EXPR<struct DB_LSN>(__tmp$B0F64_59);
1200 which is seen as a struct copy. */
1201 if (TREE_CODE (base1
) == SSA_NAME
1202 || TREE_CODE (base1
) == CONST_DECL
1203 || TREE_CODE (base1
) == CONSTRUCTOR
1204 || TREE_CODE (base1
) == ADDR_EXPR
1205 || CONSTANT_CLASS_P (base1
)
1206 || TREE_CODE (base2
) == SSA_NAME
1207 || TREE_CODE (base2
) == CONST_DECL
1208 || TREE_CODE (base2
) == CONSTRUCTOR
1209 || TREE_CODE (base2
) == ADDR_EXPR
1210 || CONSTANT_CLASS_P (base2
))
1213 /* We can end up referring to code via function and label decls.
1214 As we likely do not properly track code aliases conservatively
1216 if (TREE_CODE (base1
) == FUNCTION_DECL
1217 || TREE_CODE (base1
) == LABEL_DECL
1218 || TREE_CODE (base2
) == FUNCTION_DECL
1219 || TREE_CODE (base2
) == LABEL_DECL
)
1222 /* Two volatile accesses always conflict. */
1223 if (ref1
->volatile_p
1224 && ref2
->volatile_p
)
1227 /* Defer to simple offset based disambiguation if we have
1228 references based on two decls. Do this before defering to
1229 TBAA to handle must-alias cases in conformance with the
1230 GCC extension of allowing type-punning through unions. */
1231 var1_p
= DECL_P (base1
);
1232 var2_p
= DECL_P (base2
);
1233 if (var1_p
&& var2_p
)
1234 return decl_refs_may_alias_p (ref1
->ref
, base1
, offset1
, max_size1
,
1235 ref2
->ref
, base2
, offset2
, max_size2
);
1237 ind1_p
= (TREE_CODE (base1
) == MEM_REF
1238 || TREE_CODE (base1
) == TARGET_MEM_REF
);
1239 ind2_p
= (TREE_CODE (base2
) == MEM_REF
1240 || TREE_CODE (base2
) == TARGET_MEM_REF
);
1242 /* Canonicalize the pointer-vs-decl case. */
1243 if (ind1_p
&& var2_p
)
1248 tmp1
= offset1
; offset1
= offset2
; offset2
= tmp1
;
1249 tmp1
= max_size1
; max_size1
= max_size2
; max_size2
= tmp1
;
1250 tmp2
= base1
; base1
= base2
; base2
= tmp2
;
1251 tmp3
= ref1
; ref1
= ref2
; ref2
= tmp3
;
1258 /* First defer to TBAA if possible. */
1260 && flag_strict_aliasing
1261 && !alias_sets_conflict_p (ao_ref_alias_set (ref1
),
1262 ao_ref_alias_set (ref2
)))
1265 /* Dispatch to the pointer-vs-decl or pointer-vs-pointer disambiguators. */
1266 if (var1_p
&& ind2_p
)
1267 return indirect_ref_may_alias_decl_p (ref2
->ref
, base2
,
1269 ao_ref_alias_set (ref2
), -1,
1272 ao_ref_alias_set (ref1
),
1273 ao_ref_base_alias_set (ref1
),
1275 else if (ind1_p
&& ind2_p
)
1276 return indirect_refs_may_alias_p (ref1
->ref
, base1
,
1278 ao_ref_alias_set (ref1
), -1,
1281 ao_ref_alias_set (ref2
), -1,
1284 /* We really do not want to end up here, but returning true is safe. */
1285 #ifdef ENABLE_CHECKING
1293 refs_may_alias_p (tree ref1
, tree ref2
)
1297 ao_ref_init (&r1
, ref1
);
1298 ao_ref_init (&r2
, ref2
);
1299 res
= refs_may_alias_p_1 (&r1
, &r2
, true);
1301 ++alias_stats
.refs_may_alias_p_may_alias
;
1303 ++alias_stats
.refs_may_alias_p_no_alias
;
1307 /* Returns true if there is a anti-dependence for the STORE that
1308 executes after the LOAD. */
1311 refs_anti_dependent_p (tree load
, tree store
)
1314 ao_ref_init (&r1
, load
);
1315 ao_ref_init (&r2
, store
);
1316 return refs_may_alias_p_1 (&r1
, &r2
, false);
1319 /* Returns true if there is a output dependence for the stores
1320 STORE1 and STORE2. */
1323 refs_output_dependent_p (tree store1
, tree store2
)
1326 ao_ref_init (&r1
, store1
);
1327 ao_ref_init (&r2
, store2
);
1328 return refs_may_alias_p_1 (&r1
, &r2
, false);
1331 /* If the call CALL may use the memory reference REF return true,
1332 otherwise return false. */
1335 ref_maybe_used_by_call_p_1 (gimple call
, ao_ref
*ref
)
1339 int flags
= gimple_call_flags (call
);
1341 /* Const functions without a static chain do not implicitly use memory. */
1342 if (!gimple_call_chain (call
)
1343 && (flags
& (ECF_CONST
|ECF_NOVOPS
)))
1346 base
= ao_ref_base (ref
);
1350 /* A call that is not without side-effects might involve volatile
1351 accesses and thus conflicts with all other volatile accesses. */
1352 if (ref
->volatile_p
)
1355 /* If the reference is based on a decl that is not aliased the call
1356 cannot possibly use it. */
1358 && !may_be_aliased (base
)
1359 /* But local statics can be used through recursion. */
1360 && !is_global_var (base
))
1363 callee
= gimple_call_fndecl (call
);
1365 /* Handle those builtin functions explicitly that do not act as
1366 escape points. See tree-ssa-structalias.c:find_func_aliases
1367 for the list of builtins we might need to handle here. */
1368 if (callee
!= NULL_TREE
1369 && DECL_BUILT_IN_CLASS (callee
) == BUILT_IN_NORMAL
)
1370 switch (DECL_FUNCTION_CODE (callee
))
1372 /* All the following functions read memory pointed to by
1373 their second argument. strcat/strncat additionally
1374 reads memory pointed to by the first argument. */
1375 case BUILT_IN_STRCAT
:
1376 case BUILT_IN_STRNCAT
:
1379 ao_ref_init_from_ptr_and_size (&dref
,
1380 gimple_call_arg (call
, 0),
1382 if (refs_may_alias_p_1 (&dref
, ref
, false))
1386 case BUILT_IN_STRCPY
:
1387 case BUILT_IN_STRNCPY
:
1388 case BUILT_IN_MEMCPY
:
1389 case BUILT_IN_MEMMOVE
:
1390 case BUILT_IN_MEMPCPY
:
1391 case BUILT_IN_STPCPY
:
1392 case BUILT_IN_STPNCPY
:
1393 case BUILT_IN_TM_MEMCPY
:
1394 case BUILT_IN_TM_MEMMOVE
:
1397 tree size
= NULL_TREE
;
1398 if (gimple_call_num_args (call
) == 3)
1399 size
= gimple_call_arg (call
, 2);
1400 ao_ref_init_from_ptr_and_size (&dref
,
1401 gimple_call_arg (call
, 1),
1403 return refs_may_alias_p_1 (&dref
, ref
, false);
1405 case BUILT_IN_STRCAT_CHK
:
1406 case BUILT_IN_STRNCAT_CHK
:
1409 ao_ref_init_from_ptr_and_size (&dref
,
1410 gimple_call_arg (call
, 0),
1412 if (refs_may_alias_p_1 (&dref
, ref
, false))
1416 case BUILT_IN_STRCPY_CHK
:
1417 case BUILT_IN_STRNCPY_CHK
:
1418 case BUILT_IN_MEMCPY_CHK
:
1419 case BUILT_IN_MEMMOVE_CHK
:
1420 case BUILT_IN_MEMPCPY_CHK
:
1421 case BUILT_IN_STPCPY_CHK
:
1422 case BUILT_IN_STPNCPY_CHK
:
1425 tree size
= NULL_TREE
;
1426 if (gimple_call_num_args (call
) == 4)
1427 size
= gimple_call_arg (call
, 2);
1428 ao_ref_init_from_ptr_and_size (&dref
,
1429 gimple_call_arg (call
, 1),
1431 return refs_may_alias_p_1 (&dref
, ref
, false);
1433 case BUILT_IN_BCOPY
:
1436 tree size
= gimple_call_arg (call
, 2);
1437 ao_ref_init_from_ptr_and_size (&dref
,
1438 gimple_call_arg (call
, 0),
1440 return refs_may_alias_p_1 (&dref
, ref
, false);
1443 /* The following functions read memory pointed to by their
1445 CASE_BUILT_IN_TM_LOAD (1):
1446 CASE_BUILT_IN_TM_LOAD (2):
1447 CASE_BUILT_IN_TM_LOAD (4):
1448 CASE_BUILT_IN_TM_LOAD (8):
1449 CASE_BUILT_IN_TM_LOAD (FLOAT
):
1450 CASE_BUILT_IN_TM_LOAD (DOUBLE
):
1451 CASE_BUILT_IN_TM_LOAD (LDOUBLE
):
1452 CASE_BUILT_IN_TM_LOAD (M64
):
1453 CASE_BUILT_IN_TM_LOAD (M128
):
1454 CASE_BUILT_IN_TM_LOAD (M256
):
1455 case BUILT_IN_TM_LOG
:
1456 case BUILT_IN_TM_LOG_1
:
1457 case BUILT_IN_TM_LOG_2
:
1458 case BUILT_IN_TM_LOG_4
:
1459 case BUILT_IN_TM_LOG_8
:
1460 case BUILT_IN_TM_LOG_FLOAT
:
1461 case BUILT_IN_TM_LOG_DOUBLE
:
1462 case BUILT_IN_TM_LOG_LDOUBLE
:
1463 case BUILT_IN_TM_LOG_M64
:
1464 case BUILT_IN_TM_LOG_M128
:
1465 case BUILT_IN_TM_LOG_M256
:
1466 return ptr_deref_may_alias_ref_p_1 (gimple_call_arg (call
, 0), ref
);
1468 /* These read memory pointed to by the first argument. */
1469 case BUILT_IN_STRDUP
:
1470 case BUILT_IN_STRNDUP
:
1473 tree size
= NULL_TREE
;
1474 if (gimple_call_num_args (call
) == 2)
1475 size
= gimple_call_arg (call
, 1);
1476 ao_ref_init_from_ptr_and_size (&dref
,
1477 gimple_call_arg (call
, 0),
1479 return refs_may_alias_p_1 (&dref
, ref
, false);
1481 /* These read memory pointed to by the first argument. */
1482 case BUILT_IN_INDEX
:
1483 case BUILT_IN_STRCHR
:
1484 case BUILT_IN_STRRCHR
:
1487 ao_ref_init_from_ptr_and_size (&dref
,
1488 gimple_call_arg (call
, 0),
1490 return refs_may_alias_p_1 (&dref
, ref
, false);
1492 /* These read memory pointed to by the first argument with size
1493 in the third argument. */
1494 case BUILT_IN_MEMCHR
:
1497 ao_ref_init_from_ptr_and_size (&dref
,
1498 gimple_call_arg (call
, 0),
1499 gimple_call_arg (call
, 2));
1500 return refs_may_alias_p_1 (&dref
, ref
, false);
1502 /* These read memory pointed to by the first and second arguments. */
1503 case BUILT_IN_STRSTR
:
1504 case BUILT_IN_STRPBRK
:
1507 ao_ref_init_from_ptr_and_size (&dref
,
1508 gimple_call_arg (call
, 0),
1510 if (refs_may_alias_p_1 (&dref
, ref
, false))
1512 ao_ref_init_from_ptr_and_size (&dref
,
1513 gimple_call_arg (call
, 1),
1515 return refs_may_alias_p_1 (&dref
, ref
, false);
1518 /* The following builtins do not read from memory. */
1520 case BUILT_IN_MALLOC
:
1521 case BUILT_IN_POSIX_MEMALIGN
:
1522 case BUILT_IN_CALLOC
:
1523 case BUILT_IN_ALLOCA
:
1524 case BUILT_IN_ALLOCA_WITH_ALIGN
:
1525 case BUILT_IN_STACK_SAVE
:
1526 case BUILT_IN_STACK_RESTORE
:
1527 case BUILT_IN_MEMSET
:
1528 case BUILT_IN_TM_MEMSET
:
1529 case BUILT_IN_MEMSET_CHK
:
1530 case BUILT_IN_FREXP
:
1531 case BUILT_IN_FREXPF
:
1532 case BUILT_IN_FREXPL
:
1533 case BUILT_IN_GAMMA_R
:
1534 case BUILT_IN_GAMMAF_R
:
1535 case BUILT_IN_GAMMAL_R
:
1536 case BUILT_IN_LGAMMA_R
:
1537 case BUILT_IN_LGAMMAF_R
:
1538 case BUILT_IN_LGAMMAL_R
:
1540 case BUILT_IN_MODFF
:
1541 case BUILT_IN_MODFL
:
1542 case BUILT_IN_REMQUO
:
1543 case BUILT_IN_REMQUOF
:
1544 case BUILT_IN_REMQUOL
:
1545 case BUILT_IN_SINCOS
:
1546 case BUILT_IN_SINCOSF
:
1547 case BUILT_IN_SINCOSL
:
1548 case BUILT_IN_ASSUME_ALIGNED
:
1549 case BUILT_IN_VA_END
:
1551 /* __sync_* builtins and some OpenMP builtins act as threading
1553 #undef DEF_SYNC_BUILTIN
1554 #define DEF_SYNC_BUILTIN(ENUM, NAME, TYPE, ATTRS) case ENUM:
1555 #include "sync-builtins.def"
1556 #undef DEF_SYNC_BUILTIN
1557 case BUILT_IN_GOMP_ATOMIC_START
:
1558 case BUILT_IN_GOMP_ATOMIC_END
:
1559 case BUILT_IN_GOMP_BARRIER
:
1560 case BUILT_IN_GOMP_BARRIER_CANCEL
:
1561 case BUILT_IN_GOMP_TASKWAIT
:
1562 case BUILT_IN_GOMP_TASKGROUP_END
:
1563 case BUILT_IN_GOMP_CRITICAL_START
:
1564 case BUILT_IN_GOMP_CRITICAL_END
:
1565 case BUILT_IN_GOMP_CRITICAL_NAME_START
:
1566 case BUILT_IN_GOMP_CRITICAL_NAME_END
:
1567 case BUILT_IN_GOMP_LOOP_END
:
1568 case BUILT_IN_GOMP_LOOP_END_CANCEL
:
1569 case BUILT_IN_GOMP_ORDERED_START
:
1570 case BUILT_IN_GOMP_ORDERED_END
:
1571 case BUILT_IN_GOMP_SECTIONS_END
:
1572 case BUILT_IN_GOMP_SECTIONS_END_CANCEL
:
1573 case BUILT_IN_GOMP_SINGLE_COPY_START
:
1574 case BUILT_IN_GOMP_SINGLE_COPY_END
:
1578 /* Fallthru to general call handling. */;
1581 /* Check if base is a global static variable that is not read
1583 if (callee
!= NULL_TREE
1584 && TREE_CODE (base
) == VAR_DECL
1585 && TREE_STATIC (base
))
1587 struct cgraph_node
*node
= cgraph_get_node (callee
);
1590 /* FIXME: Callee can be an OMP builtin that does not have a call graph
1591 node yet. We should enforce that there are nodes for all decls in the
1592 IL and remove this check instead. */
1594 && (not_read
= ipa_reference_get_not_read_global (node
))
1595 && bitmap_bit_p (not_read
, DECL_UID (base
)))
1599 /* Check if the base variable is call-used. */
1602 if (pt_solution_includes (gimple_call_use_set (call
), base
))
1605 else if ((TREE_CODE (base
) == MEM_REF
1606 || TREE_CODE (base
) == TARGET_MEM_REF
)
1607 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
)
1609 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (TREE_OPERAND (base
, 0));
1613 if (pt_solutions_intersect (gimple_call_use_set (call
), &pi
->pt
))
1619 /* Inspect call arguments for passed-by-value aliases. */
1621 for (i
= 0; i
< gimple_call_num_args (call
); ++i
)
1623 tree op
= gimple_call_arg (call
, i
);
1624 int flags
= gimple_call_arg_flags (call
, i
);
1626 if (flags
& EAF_UNUSED
)
1629 if (TREE_CODE (op
) == WITH_SIZE_EXPR
)
1630 op
= TREE_OPERAND (op
, 0);
1632 if (TREE_CODE (op
) != SSA_NAME
1633 && !is_gimple_min_invariant (op
))
1636 ao_ref_init (&r
, op
);
1637 if (refs_may_alias_p_1 (&r
, ref
, true))
1646 ref_maybe_used_by_call_p (gimple call
, tree ref
)
1650 ao_ref_init (&r
, ref
);
1651 res
= ref_maybe_used_by_call_p_1 (call
, &r
);
1653 ++alias_stats
.ref_maybe_used_by_call_p_may_alias
;
1655 ++alias_stats
.ref_maybe_used_by_call_p_no_alias
;
1660 /* If the statement STMT may use the memory reference REF return
1661 true, otherwise return false. */
1664 ref_maybe_used_by_stmt_p (gimple stmt
, tree ref
)
1666 if (is_gimple_assign (stmt
))
1670 /* All memory assign statements are single. */
1671 if (!gimple_assign_single_p (stmt
))
1674 rhs
= gimple_assign_rhs1 (stmt
);
1675 if (is_gimple_reg (rhs
)
1676 || is_gimple_min_invariant (rhs
)
1677 || gimple_assign_rhs_code (stmt
) == CONSTRUCTOR
)
1680 return refs_may_alias_p (rhs
, ref
);
1682 else if (is_gimple_call (stmt
))
1683 return ref_maybe_used_by_call_p (stmt
, ref
);
1684 else if (gimple_code (stmt
) == GIMPLE_RETURN
)
1686 tree retval
= gimple_return_retval (stmt
);
1689 && TREE_CODE (retval
) != SSA_NAME
1690 && !is_gimple_min_invariant (retval
)
1691 && refs_may_alias_p (retval
, ref
))
1693 /* If ref escapes the function then the return acts as a use. */
1694 base
= get_base_address (ref
);
1697 else if (DECL_P (base
))
1698 return is_global_var (base
);
1699 else if (TREE_CODE (base
) == MEM_REF
1700 || TREE_CODE (base
) == TARGET_MEM_REF
)
1701 return ptr_deref_may_alias_global_p (TREE_OPERAND (base
, 0));
1708 /* If the call in statement CALL may clobber the memory reference REF
1709 return true, otherwise return false. */
1712 call_may_clobber_ref_p_1 (gimple call
, ao_ref
*ref
)
1717 /* If the call is pure or const it cannot clobber anything. */
1718 if (gimple_call_flags (call
)
1719 & (ECF_PURE
|ECF_CONST
|ECF_LOOPING_CONST_OR_PURE
|ECF_NOVOPS
))
1722 base
= ao_ref_base (ref
);
1726 if (TREE_CODE (base
) == SSA_NAME
1727 || CONSTANT_CLASS_P (base
))
1730 /* A call that is not without side-effects might involve volatile
1731 accesses and thus conflicts with all other volatile accesses. */
1732 if (ref
->volatile_p
)
1735 /* If the reference is based on a decl that is not aliased the call
1736 cannot possibly clobber it. */
1738 && !may_be_aliased (base
)
1739 /* But local non-readonly statics can be modified through recursion
1740 or the call may implement a threading barrier which we must
1741 treat as may-def. */
1742 && (TREE_READONLY (base
)
1743 || !is_global_var (base
)))
1746 callee
= gimple_call_fndecl (call
);
1748 /* Handle those builtin functions explicitly that do not act as
1749 escape points. See tree-ssa-structalias.c:find_func_aliases
1750 for the list of builtins we might need to handle here. */
1751 if (callee
!= NULL_TREE
1752 && DECL_BUILT_IN_CLASS (callee
) == BUILT_IN_NORMAL
)
1753 switch (DECL_FUNCTION_CODE (callee
))
1755 /* All the following functions clobber memory pointed to by
1756 their first argument. */
1757 case BUILT_IN_STRCPY
:
1758 case BUILT_IN_STRNCPY
:
1759 case BUILT_IN_MEMCPY
:
1760 case BUILT_IN_MEMMOVE
:
1761 case BUILT_IN_MEMPCPY
:
1762 case BUILT_IN_STPCPY
:
1763 case BUILT_IN_STPNCPY
:
1764 case BUILT_IN_STRCAT
:
1765 case BUILT_IN_STRNCAT
:
1766 case BUILT_IN_MEMSET
:
1767 case BUILT_IN_TM_MEMSET
:
1768 CASE_BUILT_IN_TM_STORE (1):
1769 CASE_BUILT_IN_TM_STORE (2):
1770 CASE_BUILT_IN_TM_STORE (4):
1771 CASE_BUILT_IN_TM_STORE (8):
1772 CASE_BUILT_IN_TM_STORE (FLOAT
):
1773 CASE_BUILT_IN_TM_STORE (DOUBLE
):
1774 CASE_BUILT_IN_TM_STORE (LDOUBLE
):
1775 CASE_BUILT_IN_TM_STORE (M64
):
1776 CASE_BUILT_IN_TM_STORE (M128
):
1777 CASE_BUILT_IN_TM_STORE (M256
):
1778 case BUILT_IN_TM_MEMCPY
:
1779 case BUILT_IN_TM_MEMMOVE
:
1782 tree size
= NULL_TREE
;
1783 /* Don't pass in size for strncat, as the maximum size
1784 is strlen (dest) + n + 1 instead of n, resp.
1785 n + 1 at dest + strlen (dest), but strlen (dest) isn't
1787 if (gimple_call_num_args (call
) == 3
1788 && DECL_FUNCTION_CODE (callee
) != BUILT_IN_STRNCAT
)
1789 size
= gimple_call_arg (call
, 2);
1790 ao_ref_init_from_ptr_and_size (&dref
,
1791 gimple_call_arg (call
, 0),
1793 return refs_may_alias_p_1 (&dref
, ref
, false);
1795 case BUILT_IN_STRCPY_CHK
:
1796 case BUILT_IN_STRNCPY_CHK
:
1797 case BUILT_IN_MEMCPY_CHK
:
1798 case BUILT_IN_MEMMOVE_CHK
:
1799 case BUILT_IN_MEMPCPY_CHK
:
1800 case BUILT_IN_STPCPY_CHK
:
1801 case BUILT_IN_STPNCPY_CHK
:
1802 case BUILT_IN_STRCAT_CHK
:
1803 case BUILT_IN_STRNCAT_CHK
:
1804 case BUILT_IN_MEMSET_CHK
:
1807 tree size
= NULL_TREE
;
1808 /* Don't pass in size for __strncat_chk, as the maximum size
1809 is strlen (dest) + n + 1 instead of n, resp.
1810 n + 1 at dest + strlen (dest), but strlen (dest) isn't
1812 if (gimple_call_num_args (call
) == 4
1813 && DECL_FUNCTION_CODE (callee
) != BUILT_IN_STRNCAT_CHK
)
1814 size
= gimple_call_arg (call
, 2);
1815 ao_ref_init_from_ptr_and_size (&dref
,
1816 gimple_call_arg (call
, 0),
1818 return refs_may_alias_p_1 (&dref
, ref
, false);
1820 case BUILT_IN_BCOPY
:
1823 tree size
= gimple_call_arg (call
, 2);
1824 ao_ref_init_from_ptr_and_size (&dref
,
1825 gimple_call_arg (call
, 1),
1827 return refs_may_alias_p_1 (&dref
, ref
, false);
1829 /* Allocating memory does not have any side-effects apart from
1830 being the definition point for the pointer. */
1831 case BUILT_IN_MALLOC
:
1832 case BUILT_IN_CALLOC
:
1833 case BUILT_IN_STRDUP
:
1834 case BUILT_IN_STRNDUP
:
1835 /* Unix98 specifies that errno is set on allocation failure. */
1837 && targetm
.ref_may_alias_errno (ref
))
1840 case BUILT_IN_STACK_SAVE
:
1841 case BUILT_IN_ALLOCA
:
1842 case BUILT_IN_ALLOCA_WITH_ALIGN
:
1843 case BUILT_IN_ASSUME_ALIGNED
:
1845 /* But posix_memalign stores a pointer into the memory pointed to
1846 by its first argument. */
1847 case BUILT_IN_POSIX_MEMALIGN
:
1849 tree ptrptr
= gimple_call_arg (call
, 0);
1851 ao_ref_init_from_ptr_and_size (&dref
, ptrptr
,
1852 TYPE_SIZE_UNIT (ptr_type_node
));
1853 return (refs_may_alias_p_1 (&dref
, ref
, false)
1855 && targetm
.ref_may_alias_errno (ref
)));
1857 /* Freeing memory kills the pointed-to memory. More importantly
1858 the call has to serve as a barrier for moving loads and stores
1861 case BUILT_IN_VA_END
:
1863 tree ptr
= gimple_call_arg (call
, 0);
1864 return ptr_deref_may_alias_ref_p_1 (ptr
, ref
);
1866 case BUILT_IN_GAMMA_R
:
1867 case BUILT_IN_GAMMAF_R
:
1868 case BUILT_IN_GAMMAL_R
:
1869 case BUILT_IN_LGAMMA_R
:
1870 case BUILT_IN_LGAMMAF_R
:
1871 case BUILT_IN_LGAMMAL_R
:
1873 tree out
= gimple_call_arg (call
, 1);
1874 if (ptr_deref_may_alias_ref_p_1 (out
, ref
))
1876 if (flag_errno_math
)
1880 case BUILT_IN_FREXP
:
1881 case BUILT_IN_FREXPF
:
1882 case BUILT_IN_FREXPL
:
1884 case BUILT_IN_MODFF
:
1885 case BUILT_IN_MODFL
:
1887 tree out
= gimple_call_arg (call
, 1);
1888 return ptr_deref_may_alias_ref_p_1 (out
, ref
);
1890 case BUILT_IN_REMQUO
:
1891 case BUILT_IN_REMQUOF
:
1892 case BUILT_IN_REMQUOL
:
1894 tree out
= gimple_call_arg (call
, 2);
1895 if (ptr_deref_may_alias_ref_p_1 (out
, ref
))
1897 if (flag_errno_math
)
1901 case BUILT_IN_SINCOS
:
1902 case BUILT_IN_SINCOSF
:
1903 case BUILT_IN_SINCOSL
:
1905 tree sin
= gimple_call_arg (call
, 1);
1906 tree cos
= gimple_call_arg (call
, 2);
1907 return (ptr_deref_may_alias_ref_p_1 (sin
, ref
)
1908 || ptr_deref_may_alias_ref_p_1 (cos
, ref
));
1910 /* __sync_* builtins and some OpenMP builtins act as threading
1912 #undef DEF_SYNC_BUILTIN
1913 #define DEF_SYNC_BUILTIN(ENUM, NAME, TYPE, ATTRS) case ENUM:
1914 #include "sync-builtins.def"
1915 #undef DEF_SYNC_BUILTIN
1916 case BUILT_IN_GOMP_ATOMIC_START
:
1917 case BUILT_IN_GOMP_ATOMIC_END
:
1918 case BUILT_IN_GOMP_BARRIER
:
1919 case BUILT_IN_GOMP_BARRIER_CANCEL
:
1920 case BUILT_IN_GOMP_TASKWAIT
:
1921 case BUILT_IN_GOMP_TASKGROUP_END
:
1922 case BUILT_IN_GOMP_CRITICAL_START
:
1923 case BUILT_IN_GOMP_CRITICAL_END
:
1924 case BUILT_IN_GOMP_CRITICAL_NAME_START
:
1925 case BUILT_IN_GOMP_CRITICAL_NAME_END
:
1926 case BUILT_IN_GOMP_LOOP_END
:
1927 case BUILT_IN_GOMP_LOOP_END_CANCEL
:
1928 case BUILT_IN_GOMP_ORDERED_START
:
1929 case BUILT_IN_GOMP_ORDERED_END
:
1930 case BUILT_IN_GOMP_SECTIONS_END
:
1931 case BUILT_IN_GOMP_SECTIONS_END_CANCEL
:
1932 case BUILT_IN_GOMP_SINGLE_COPY_START
:
1933 case BUILT_IN_GOMP_SINGLE_COPY_END
:
1936 /* Fallthru to general call handling. */;
1939 /* Check if base is a global static variable that is not written
1941 if (callee
!= NULL_TREE
1942 && TREE_CODE (base
) == VAR_DECL
1943 && TREE_STATIC (base
))
1945 struct cgraph_node
*node
= cgraph_get_node (callee
);
1949 && (not_written
= ipa_reference_get_not_written_global (node
))
1950 && bitmap_bit_p (not_written
, DECL_UID (base
)))
1954 /* Check if the base variable is call-clobbered. */
1956 return pt_solution_includes (gimple_call_clobber_set (call
), base
);
1957 else if ((TREE_CODE (base
) == MEM_REF
1958 || TREE_CODE (base
) == TARGET_MEM_REF
)
1959 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
)
1961 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (TREE_OPERAND (base
, 0));
1965 return pt_solutions_intersect (gimple_call_clobber_set (call
), &pi
->pt
);
1971 /* If the call in statement CALL may clobber the memory reference REF
1972 return true, otherwise return false. */
1975 call_may_clobber_ref_p (gimple call
, tree ref
)
1979 ao_ref_init (&r
, ref
);
1980 res
= call_may_clobber_ref_p_1 (call
, &r
);
1982 ++alias_stats
.call_may_clobber_ref_p_may_alias
;
1984 ++alias_stats
.call_may_clobber_ref_p_no_alias
;
1989 /* If the statement STMT may clobber the memory reference REF return true,
1990 otherwise return false. */
1993 stmt_may_clobber_ref_p_1 (gimple stmt
, ao_ref
*ref
)
1995 if (is_gimple_call (stmt
))
1997 tree lhs
= gimple_call_lhs (stmt
);
1999 && TREE_CODE (lhs
) != SSA_NAME
)
2002 ao_ref_init (&r
, lhs
);
2003 if (refs_may_alias_p_1 (ref
, &r
, true))
2007 return call_may_clobber_ref_p_1 (stmt
, ref
);
2009 else if (gimple_assign_single_p (stmt
))
2011 tree lhs
= gimple_assign_lhs (stmt
);
2012 if (TREE_CODE (lhs
) != SSA_NAME
)
2015 ao_ref_init (&r
, lhs
);
2016 return refs_may_alias_p_1 (ref
, &r
, true);
2019 else if (gimple_code (stmt
) == GIMPLE_ASM
)
2026 stmt_may_clobber_ref_p (gimple stmt
, tree ref
)
2029 ao_ref_init (&r
, ref
);
2030 return stmt_may_clobber_ref_p_1 (stmt
, &r
);
2033 /* If STMT kills the memory reference REF return true, otherwise
2037 stmt_kills_ref_p_1 (gimple stmt
, ao_ref
*ref
)
2039 /* For a must-alias check we need to be able to constrain
2040 the access properly.
2041 FIXME: except for BUILTIN_FREE. */
2042 if (!ao_ref_base (ref
)
2043 || ref
->max_size
== -1)
2046 if (gimple_has_lhs (stmt
)
2047 && TREE_CODE (gimple_get_lhs (stmt
)) != SSA_NAME
2048 /* The assignment is not necessarily carried out if it can throw
2049 and we can catch it in the current function where we could inspect
2051 ??? We only need to care about the RHS throwing. For aggregate
2052 assignments or similar calls and non-call exceptions the LHS
2053 might throw as well. */
2054 && !stmt_can_throw_internal (stmt
))
2056 tree base
, lhs
= gimple_get_lhs (stmt
);
2057 HOST_WIDE_INT size
, offset
, max_size
, ref_offset
= ref
->offset
;
2058 base
= get_ref_base_and_extent (lhs
, &offset
, &size
, &max_size
);
2059 /* We can get MEM[symbol: sZ, index: D.8862_1] here,
2060 so base == ref->base does not always hold. */
2061 if (base
!= ref
->base
)
2063 /* If both base and ref->base are MEM_REFs, only compare the
2064 first operand, and if the second operand isn't equal constant,
2065 try to add the offsets into offset and ref_offset. */
2066 if (TREE_CODE (base
) == MEM_REF
&& TREE_CODE (ref
->base
) == MEM_REF
2067 && TREE_OPERAND (base
, 0) == TREE_OPERAND (ref
->base
, 0))
2069 if (!tree_int_cst_equal (TREE_OPERAND (base
, 1),
2070 TREE_OPERAND (ref
->base
, 1)))
2072 offset_int off1
= mem_ref_offset (base
);
2073 off1
= wi::lshift (off1
, (BITS_PER_UNIT
== 8
2074 ? 3 : exact_log2 (BITS_PER_UNIT
)));
2076 offset_int off2
= mem_ref_offset (ref
->base
);
2077 off2
= wi::lshift (off2
, (BITS_PER_UNIT
== 8
2078 ? 3 : exact_log2 (BITS_PER_UNIT
)));
2080 if (wi::fits_shwi_p (off1
) && wi::fits_shwi_p (off2
))
2082 offset
= off1
.to_shwi ();
2083 ref_offset
= off2
.to_shwi ();
2092 /* For a must-alias check we need to be able to constrain
2093 the access properly. */
2094 if (size
!= -1 && size
== max_size
)
2096 if (offset
<= ref_offset
2097 && offset
+ size
>= ref_offset
+ ref
->max_size
)
2102 if (is_gimple_call (stmt
))
2104 tree callee
= gimple_call_fndecl (stmt
);
2105 if (callee
!= NULL_TREE
2106 && DECL_BUILT_IN_CLASS (callee
) == BUILT_IN_NORMAL
)
2107 switch (DECL_FUNCTION_CODE (callee
))
2111 tree ptr
= gimple_call_arg (stmt
, 0);
2112 tree base
= ao_ref_base (ref
);
2113 if (base
&& TREE_CODE (base
) == MEM_REF
2114 && TREE_OPERAND (base
, 0) == ptr
)
2119 case BUILT_IN_MEMCPY
:
2120 case BUILT_IN_MEMPCPY
:
2121 case BUILT_IN_MEMMOVE
:
2122 case BUILT_IN_MEMSET
:
2123 case BUILT_IN_MEMCPY_CHK
:
2124 case BUILT_IN_MEMPCPY_CHK
:
2125 case BUILT_IN_MEMMOVE_CHK
:
2126 case BUILT_IN_MEMSET_CHK
:
2128 tree dest
= gimple_call_arg (stmt
, 0);
2129 tree len
= gimple_call_arg (stmt
, 2);
2130 if (!tree_fits_shwi_p (len
))
2132 tree rbase
= ref
->base
;
2133 offset_int roffset
= ref
->offset
;
2135 ao_ref_init_from_ptr_and_size (&dref
, dest
, len
);
2136 tree base
= ao_ref_base (&dref
);
2137 offset_int offset
= dref
.offset
;
2138 if (!base
|| dref
.size
== -1)
2140 if (TREE_CODE (base
) == MEM_REF
)
2142 if (TREE_CODE (rbase
) != MEM_REF
)
2144 // Compare pointers.
2145 offset
+= wi::lshift (mem_ref_offset (base
),
2146 LOG2_BITS_PER_UNIT
);
2147 roffset
+= wi::lshift (mem_ref_offset (rbase
),
2148 LOG2_BITS_PER_UNIT
);
2149 base
= TREE_OPERAND (base
, 0);
2150 rbase
= TREE_OPERAND (rbase
, 0);
2153 && wi::les_p (offset
, roffset
)
2154 && wi::les_p (roffset
+ ref
->max_size
,
2155 offset
+ wi::lshift (wi::to_offset (len
),
2156 LOG2_BITS_PER_UNIT
)))
2161 case BUILT_IN_VA_END
:
2163 tree ptr
= gimple_call_arg (stmt
, 0);
2164 if (TREE_CODE (ptr
) == ADDR_EXPR
)
2166 tree base
= ao_ref_base (ref
);
2167 if (TREE_OPERAND (ptr
, 0) == base
)
2180 stmt_kills_ref_p (gimple stmt
, tree ref
)
2183 ao_ref_init (&r
, ref
);
2184 return stmt_kills_ref_p_1 (stmt
, &r
);
2188 /* Walk the virtual use-def chain of VUSE until hitting the virtual operand
2189 TARGET or a statement clobbering the memory reference REF in which
2190 case false is returned. The walk starts with VUSE, one argument of PHI. */
2193 maybe_skip_until (gimple phi
, tree target
, ao_ref
*ref
,
2194 tree vuse
, unsigned int *cnt
, bitmap
*visited
,
2195 bool abort_on_visited
)
2197 basic_block bb
= gimple_bb (phi
);
2200 *visited
= BITMAP_ALLOC (NULL
);
2202 bitmap_set_bit (*visited
, SSA_NAME_VERSION (PHI_RESULT (phi
)));
2204 /* Walk until we hit the target. */
2205 while (vuse
!= target
)
2207 gimple def_stmt
= SSA_NAME_DEF_STMT (vuse
);
2208 /* Recurse for PHI nodes. */
2209 if (gimple_code (def_stmt
) == GIMPLE_PHI
)
2211 /* An already visited PHI node ends the walk successfully. */
2212 if (bitmap_bit_p (*visited
, SSA_NAME_VERSION (PHI_RESULT (def_stmt
))))
2213 return !abort_on_visited
;
2214 vuse
= get_continuation_for_phi (def_stmt
, ref
, cnt
,
2215 visited
, abort_on_visited
);
2220 else if (gimple_nop_p (def_stmt
))
2224 /* A clobbering statement or the end of the IL ends it failing. */
2226 if (stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
2229 /* If we reach a new basic-block see if we already skipped it
2230 in a previous walk that ended successfully. */
2231 if (gimple_bb (def_stmt
) != bb
)
2233 if (!bitmap_set_bit (*visited
, SSA_NAME_VERSION (vuse
)))
2234 return !abort_on_visited
;
2235 bb
= gimple_bb (def_stmt
);
2237 vuse
= gimple_vuse (def_stmt
);
2242 /* For two PHI arguments ARG0 and ARG1 try to skip non-aliasing code
2243 until we hit the phi argument definition that dominates the other one.
2244 Return that, or NULL_TREE if there is no such definition. */
2247 get_continuation_for_phi_1 (gimple phi
, tree arg0
, tree arg1
,
2248 ao_ref
*ref
, unsigned int *cnt
,
2249 bitmap
*visited
, bool abort_on_visited
)
2251 gimple def0
= SSA_NAME_DEF_STMT (arg0
);
2252 gimple def1
= SSA_NAME_DEF_STMT (arg1
);
2257 else if (gimple_nop_p (def0
)
2258 || (!gimple_nop_p (def1
)
2259 && dominated_by_p (CDI_DOMINATORS
,
2260 gimple_bb (def1
), gimple_bb (def0
))))
2262 if (maybe_skip_until (phi
, arg0
, ref
, arg1
, cnt
,
2263 visited
, abort_on_visited
))
2266 else if (gimple_nop_p (def1
)
2267 || dominated_by_p (CDI_DOMINATORS
,
2268 gimple_bb (def0
), gimple_bb (def1
)))
2270 if (maybe_skip_until (phi
, arg1
, ref
, arg0
, cnt
,
2271 visited
, abort_on_visited
))
2274 /* Special case of a diamond:
2276 goto (cond) ? L1 : L2
2277 L1: store1 = ... #MEM_2 = vuse(MEM_1)
2279 L2: store2 = ... #MEM_3 = vuse(MEM_1)
2280 L3: MEM_4 = PHI<MEM_2, MEM_3>
2281 We were called with the PHI at L3, MEM_2 and MEM_3 don't
2282 dominate each other, but still we can easily skip this PHI node
2283 if we recognize that the vuse MEM operand is the same for both,
2284 and that we can skip both statements (they don't clobber us).
2285 This is still linear. Don't use maybe_skip_until, that might
2286 potentially be slow. */
2287 else if ((common_vuse
= gimple_vuse (def0
))
2288 && common_vuse
== gimple_vuse (def1
))
2291 if (!stmt_may_clobber_ref_p_1 (def0
, ref
)
2292 && !stmt_may_clobber_ref_p_1 (def1
, ref
))
2300 /* Starting from a PHI node for the virtual operand of the memory reference
2301 REF find a continuation virtual operand that allows to continue walking
2302 statements dominating PHI skipping only statements that cannot possibly
2303 clobber REF. Increments *CNT for each alias disambiguation done.
2304 Returns NULL_TREE if no suitable virtual operand can be found. */
2307 get_continuation_for_phi (gimple phi
, ao_ref
*ref
,
2308 unsigned int *cnt
, bitmap
*visited
,
2309 bool abort_on_visited
)
2311 unsigned nargs
= gimple_phi_num_args (phi
);
2313 /* Through a single-argument PHI we can simply look through. */
2315 return PHI_ARG_DEF (phi
, 0);
2317 /* For two or more arguments try to pairwise skip non-aliasing code
2318 until we hit the phi argument definition that dominates the other one. */
2319 else if (nargs
>= 2)
2324 /* Find a candidate for the virtual operand which definition
2325 dominates those of all others. */
2326 arg0
= PHI_ARG_DEF (phi
, 0);
2327 if (!SSA_NAME_IS_DEFAULT_DEF (arg0
))
2328 for (i
= 1; i
< nargs
; ++i
)
2330 arg1
= PHI_ARG_DEF (phi
, i
);
2331 if (SSA_NAME_IS_DEFAULT_DEF (arg1
))
2336 if (dominated_by_p (CDI_DOMINATORS
,
2337 gimple_bb (SSA_NAME_DEF_STMT (arg0
)),
2338 gimple_bb (SSA_NAME_DEF_STMT (arg1
))))
2342 /* Then pairwise reduce against the found candidate. */
2343 for (i
= 0; i
< nargs
; ++i
)
2345 arg1
= PHI_ARG_DEF (phi
, i
);
2346 arg0
= get_continuation_for_phi_1 (phi
, arg0
, arg1
, ref
,
2347 cnt
, visited
, abort_on_visited
);
2358 /* Based on the memory reference REF and its virtual use VUSE call
2359 WALKER for each virtual use that is equivalent to VUSE, including VUSE
2360 itself. That is, for each virtual use for which its defining statement
2361 does not clobber REF.
2363 WALKER is called with REF, the current virtual use and DATA. If
2364 WALKER returns non-NULL the walk stops and its result is returned.
2365 At the end of a non-successful walk NULL is returned.
2367 TRANSLATE if non-NULL is called with a pointer to REF, the virtual
2368 use which definition is a statement that may clobber REF and DATA.
2369 If TRANSLATE returns (void *)-1 the walk stops and NULL is returned.
2370 If TRANSLATE returns non-NULL the walk stops and its result is returned.
2371 If TRANSLATE returns NULL the walk continues and TRANSLATE is supposed
2372 to adjust REF and *DATA to make that valid.
2374 TODO: Cache the vector of equivalent vuses per ref, vuse pair. */
2377 walk_non_aliased_vuses (ao_ref
*ref
, tree vuse
,
2378 void *(*walker
)(ao_ref
*, tree
, unsigned int, void *),
2379 void *(*translate
)(ao_ref
*, tree
, void *), void *data
)
2381 bitmap visited
= NULL
;
2383 unsigned int cnt
= 0;
2384 bool translated
= false;
2386 timevar_push (TV_ALIAS_STMT_WALK
);
2392 /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */
2393 res
= (*walker
) (ref
, vuse
, cnt
, data
);
2395 if (res
== (void *)-1)
2400 /* Lookup succeeded. */
2401 else if (res
!= NULL
)
2404 def_stmt
= SSA_NAME_DEF_STMT (vuse
);
2405 if (gimple_nop_p (def_stmt
))
2407 else if (gimple_code (def_stmt
) == GIMPLE_PHI
)
2408 vuse
= get_continuation_for_phi (def_stmt
, ref
, &cnt
,
2409 &visited
, translated
);
2413 if (stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
2417 res
= (*translate
) (ref
, vuse
, data
);
2418 /* Failed lookup and translation. */
2419 if (res
== (void *)-1)
2424 /* Lookup succeeded. */
2425 else if (res
!= NULL
)
2427 /* Translation succeeded, continue walking. */
2430 vuse
= gimple_vuse (def_stmt
);
2436 BITMAP_FREE (visited
);
2438 timevar_pop (TV_ALIAS_STMT_WALK
);
2444 /* Based on the memory reference REF call WALKER for each vdef which
2445 defining statement may clobber REF, starting with VDEF. If REF
2446 is NULL_TREE, each defining statement is visited.
2448 WALKER is called with REF, the current vdef and DATA. If WALKER
2449 returns true the walk is stopped, otherwise it continues.
2451 At PHI nodes walk_aliased_vdefs forks into one walk for reach
2452 PHI argument (but only one walk continues on merge points), the
2453 return value is true if any of the walks was successful.
2455 The function returns the number of statements walked. */
2458 walk_aliased_vdefs_1 (ao_ref
*ref
, tree vdef
,
2459 bool (*walker
)(ao_ref
*, tree
, void *), void *data
,
2460 bitmap
*visited
, unsigned int cnt
)
2464 gimple def_stmt
= SSA_NAME_DEF_STMT (vdef
);
2467 && !bitmap_set_bit (*visited
, SSA_NAME_VERSION (vdef
)))
2470 if (gimple_nop_p (def_stmt
))
2472 else if (gimple_code (def_stmt
) == GIMPLE_PHI
)
2476 *visited
= BITMAP_ALLOC (NULL
);
2477 for (i
= 0; i
< gimple_phi_num_args (def_stmt
); ++i
)
2478 cnt
+= walk_aliased_vdefs_1 (ref
, gimple_phi_arg_def (def_stmt
, i
),
2479 walker
, data
, visited
, 0);
2483 /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */
2486 || stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
2487 && (*walker
) (ref
, vdef
, data
))
2490 vdef
= gimple_vuse (def_stmt
);
2496 walk_aliased_vdefs (ao_ref
*ref
, tree vdef
,
2497 bool (*walker
)(ao_ref
*, tree
, void *), void *data
,
2500 bitmap local_visited
= NULL
;
2503 timevar_push (TV_ALIAS_STMT_WALK
);
2505 ret
= walk_aliased_vdefs_1 (ref
, vdef
, walker
, data
,
2506 visited
? visited
: &local_visited
, 0);
2508 BITMAP_FREE (local_visited
);
2510 timevar_pop (TV_ALIAS_STMT_WALK
);