1 /* Alias analysis for trees.
2 Copyright (C) 2004-2019 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"
29 #include "timevar.h" /* for TV_ALIAS_STMT_WALK */
32 #include "tree-pretty-print.h"
34 #include "fold-const.h"
35 #include "langhooks.h"
39 #include "ipa-reference.h"
42 /* Broad overview of how alias analysis on gimple works:
44 Statements clobbering or using memory are linked through the
45 virtual operand factored use-def chain. The virtual operand
46 is unique per function, its symbol is accessible via gimple_vop (cfun).
47 Virtual operands are used for efficiently walking memory statements
48 in the gimple IL and are useful for things like value-numbering as
49 a generation count for memory references.
51 SSA_NAME pointers may have associated points-to information
52 accessible via the SSA_NAME_PTR_INFO macro. Flow-insensitive
53 points-to information is (re-)computed by the TODO_rebuild_alias
54 pass manager todo. Points-to information is also used for more
55 precise tracking of call-clobbered and call-used variables and
56 related disambiguations.
58 This file contains functions for disambiguating memory references,
59 the so called alias-oracle and tools for walking of the gimple IL.
61 The main alias-oracle entry-points are
63 bool stmt_may_clobber_ref_p (gimple *, tree)
65 This function queries if a statement may invalidate (parts of)
66 the memory designated by the reference tree argument.
68 bool ref_maybe_used_by_stmt_p (gimple *, tree)
70 This function queries if a statement may need (parts of) the
71 memory designated by the reference tree argument.
73 There are variants of these functions that only handle the call
74 part of a statement, call_may_clobber_ref_p and ref_maybe_used_by_call_p.
75 Note that these do not disambiguate against a possible call lhs.
77 bool refs_may_alias_p (tree, tree)
79 This function tries to disambiguate two reference trees.
81 bool ptr_deref_may_alias_global_p (tree)
83 This function queries if dereferencing a pointer variable may
86 More low-level disambiguators are available and documented in
87 this file. Low-level disambiguators dealing with points-to
88 information are in tree-ssa-structalias.c. */
90 static int nonoverlapping_component_refs_since_match_p (tree
, tree
, tree
, tree
);
91 static bool nonoverlapping_component_refs_p (const_tree
, const_tree
);
93 /* Query statistics for the different low-level disambiguators.
94 A high-level query may trigger multiple of them. */
97 unsigned HOST_WIDE_INT refs_may_alias_p_may_alias
;
98 unsigned HOST_WIDE_INT refs_may_alias_p_no_alias
;
99 unsigned HOST_WIDE_INT ref_maybe_used_by_call_p_may_alias
;
100 unsigned HOST_WIDE_INT ref_maybe_used_by_call_p_no_alias
;
101 unsigned HOST_WIDE_INT call_may_clobber_ref_p_may_alias
;
102 unsigned HOST_WIDE_INT call_may_clobber_ref_p_no_alias
;
103 unsigned HOST_WIDE_INT aliasing_component_refs_p_may_alias
;
104 unsigned HOST_WIDE_INT aliasing_component_refs_p_no_alias
;
105 unsigned HOST_WIDE_INT nonoverlapping_component_refs_p_may_alias
;
106 unsigned HOST_WIDE_INT nonoverlapping_component_refs_p_no_alias
;
107 unsigned HOST_WIDE_INT nonoverlapping_component_refs_since_match_p_may_alias
;
108 unsigned HOST_WIDE_INT nonoverlapping_component_refs_since_match_p_must_overlap
;
109 unsigned HOST_WIDE_INT nonoverlapping_component_refs_since_match_p_no_alias
;
113 dump_alias_stats (FILE *s
)
115 fprintf (s
, "\nAlias oracle query stats:\n");
116 fprintf (s
, " refs_may_alias_p: "
117 HOST_WIDE_INT_PRINT_DEC
" disambiguations, "
118 HOST_WIDE_INT_PRINT_DEC
" queries\n",
119 alias_stats
.refs_may_alias_p_no_alias
,
120 alias_stats
.refs_may_alias_p_no_alias
121 + alias_stats
.refs_may_alias_p_may_alias
);
122 fprintf (s
, " ref_maybe_used_by_call_p: "
123 HOST_WIDE_INT_PRINT_DEC
" disambiguations, "
124 HOST_WIDE_INT_PRINT_DEC
" queries\n",
125 alias_stats
.ref_maybe_used_by_call_p_no_alias
,
126 alias_stats
.refs_may_alias_p_no_alias
127 + alias_stats
.ref_maybe_used_by_call_p_may_alias
);
128 fprintf (s
, " call_may_clobber_ref_p: "
129 HOST_WIDE_INT_PRINT_DEC
" disambiguations, "
130 HOST_WIDE_INT_PRINT_DEC
" queries\n",
131 alias_stats
.call_may_clobber_ref_p_no_alias
,
132 alias_stats
.call_may_clobber_ref_p_no_alias
133 + alias_stats
.call_may_clobber_ref_p_may_alias
);
134 fprintf (s
, " nonoverlapping_component_refs_p: "
135 HOST_WIDE_INT_PRINT_DEC
" disambiguations, "
136 HOST_WIDE_INT_PRINT_DEC
" queries\n",
137 alias_stats
.nonoverlapping_component_refs_p_no_alias
,
138 alias_stats
.nonoverlapping_component_refs_p_no_alias
139 + alias_stats
.nonoverlapping_component_refs_p_may_alias
);
140 fprintf (s
, " nonoverlapping_component_refs_since_match_p: "
141 HOST_WIDE_INT_PRINT_DEC
" disambiguations, "
142 HOST_WIDE_INT_PRINT_DEC
" must overlaps, "
143 HOST_WIDE_INT_PRINT_DEC
" queries\n",
144 alias_stats
.nonoverlapping_component_refs_since_match_p_no_alias
,
145 alias_stats
.nonoverlapping_component_refs_since_match_p_must_overlap
,
146 alias_stats
.nonoverlapping_component_refs_since_match_p_no_alias
147 + alias_stats
.nonoverlapping_component_refs_since_match_p_may_alias
148 + alias_stats
.nonoverlapping_component_refs_since_match_p_must_overlap
);
149 fprintf (s
, " aliasing_component_refs_p: "
150 HOST_WIDE_INT_PRINT_DEC
" disambiguations, "
151 HOST_WIDE_INT_PRINT_DEC
" queries\n",
152 alias_stats
.aliasing_component_refs_p_no_alias
,
153 alias_stats
.aliasing_component_refs_p_no_alias
154 + alias_stats
.aliasing_component_refs_p_may_alias
);
155 dump_alias_stats_in_alias_c (s
);
159 /* Return true, if dereferencing PTR may alias with a global variable. */
162 ptr_deref_may_alias_global_p (tree ptr
)
164 struct ptr_info_def
*pi
;
166 /* If we end up with a pointer constant here that may point
168 if (TREE_CODE (ptr
) != SSA_NAME
)
171 pi
= SSA_NAME_PTR_INFO (ptr
);
173 /* If we do not have points-to information for this variable,
178 /* ??? This does not use TBAA to prune globals ptr may not access. */
179 return pt_solution_includes_global (&pi
->pt
);
182 /* Return true if dereferencing PTR may alias DECL.
183 The caller is responsible for applying TBAA to see if PTR
184 may access DECL at all. */
187 ptr_deref_may_alias_decl_p (tree ptr
, tree decl
)
189 struct ptr_info_def
*pi
;
191 /* Conversions are irrelevant for points-to information and
192 data-dependence analysis can feed us those. */
195 /* Anything we do not explicilty handle aliases. */
196 if ((TREE_CODE (ptr
) != SSA_NAME
197 && TREE_CODE (ptr
) != ADDR_EXPR
198 && TREE_CODE (ptr
) != POINTER_PLUS_EXPR
)
199 || !POINTER_TYPE_P (TREE_TYPE (ptr
))
201 && TREE_CODE (decl
) != PARM_DECL
202 && TREE_CODE (decl
) != RESULT_DECL
))
205 /* Disregard pointer offsetting. */
206 if (TREE_CODE (ptr
) == POINTER_PLUS_EXPR
)
210 ptr
= TREE_OPERAND (ptr
, 0);
212 while (TREE_CODE (ptr
) == POINTER_PLUS_EXPR
);
213 return ptr_deref_may_alias_decl_p (ptr
, decl
);
216 /* ADDR_EXPR pointers either just offset another pointer or directly
217 specify the pointed-to set. */
218 if (TREE_CODE (ptr
) == ADDR_EXPR
)
220 tree base
= get_base_address (TREE_OPERAND (ptr
, 0));
222 && (TREE_CODE (base
) == MEM_REF
223 || TREE_CODE (base
) == TARGET_MEM_REF
))
224 ptr
= TREE_OPERAND (base
, 0);
227 return compare_base_decls (base
, decl
) != 0;
229 && CONSTANT_CLASS_P (base
))
235 /* Non-aliased variables cannot be pointed to. */
236 if (!may_be_aliased (decl
))
239 /* If we do not have useful points-to information for this pointer
240 we cannot disambiguate anything else. */
241 pi
= SSA_NAME_PTR_INFO (ptr
);
245 return pt_solution_includes (&pi
->pt
, decl
);
248 /* Return true if dereferenced PTR1 and PTR2 may alias.
249 The caller is responsible for applying TBAA to see if accesses
250 through PTR1 and PTR2 may conflict at all. */
253 ptr_derefs_may_alias_p (tree ptr1
, tree ptr2
)
255 struct ptr_info_def
*pi1
, *pi2
;
257 /* Conversions are irrelevant for points-to information and
258 data-dependence analysis can feed us those. */
262 /* Disregard pointer offsetting. */
263 if (TREE_CODE (ptr1
) == POINTER_PLUS_EXPR
)
267 ptr1
= TREE_OPERAND (ptr1
, 0);
269 while (TREE_CODE (ptr1
) == POINTER_PLUS_EXPR
);
270 return ptr_derefs_may_alias_p (ptr1
, ptr2
);
272 if (TREE_CODE (ptr2
) == POINTER_PLUS_EXPR
)
276 ptr2
= TREE_OPERAND (ptr2
, 0);
278 while (TREE_CODE (ptr2
) == POINTER_PLUS_EXPR
);
279 return ptr_derefs_may_alias_p (ptr1
, ptr2
);
282 /* ADDR_EXPR pointers either just offset another pointer or directly
283 specify the pointed-to set. */
284 if (TREE_CODE (ptr1
) == ADDR_EXPR
)
286 tree base
= get_base_address (TREE_OPERAND (ptr1
, 0));
288 && (TREE_CODE (base
) == MEM_REF
289 || TREE_CODE (base
) == TARGET_MEM_REF
))
290 return ptr_derefs_may_alias_p (TREE_OPERAND (base
, 0), ptr2
);
293 return ptr_deref_may_alias_decl_p (ptr2
, base
);
297 if (TREE_CODE (ptr2
) == ADDR_EXPR
)
299 tree base
= get_base_address (TREE_OPERAND (ptr2
, 0));
301 && (TREE_CODE (base
) == MEM_REF
302 || TREE_CODE (base
) == TARGET_MEM_REF
))
303 return ptr_derefs_may_alias_p (ptr1
, TREE_OPERAND (base
, 0));
306 return ptr_deref_may_alias_decl_p (ptr1
, base
);
311 /* From here we require SSA name pointers. Anything else aliases. */
312 if (TREE_CODE (ptr1
) != SSA_NAME
313 || TREE_CODE (ptr2
) != SSA_NAME
314 || !POINTER_TYPE_P (TREE_TYPE (ptr1
))
315 || !POINTER_TYPE_P (TREE_TYPE (ptr2
)))
318 /* We may end up with two empty points-to solutions for two same pointers.
319 In this case we still want to say both pointers alias, so shortcut
324 /* If we do not have useful points-to information for either pointer
325 we cannot disambiguate anything else. */
326 pi1
= SSA_NAME_PTR_INFO (ptr1
);
327 pi2
= SSA_NAME_PTR_INFO (ptr2
);
331 /* ??? This does not use TBAA to prune decls from the intersection
332 that not both pointers may access. */
333 return pt_solutions_intersect (&pi1
->pt
, &pi2
->pt
);
336 /* Return true if dereferencing PTR may alias *REF.
337 The caller is responsible for applying TBAA to see if PTR
338 may access *REF at all. */
341 ptr_deref_may_alias_ref_p_1 (tree ptr
, ao_ref
*ref
)
343 tree base
= ao_ref_base (ref
);
345 if (TREE_CODE (base
) == MEM_REF
346 || TREE_CODE (base
) == TARGET_MEM_REF
)
347 return ptr_derefs_may_alias_p (ptr
, TREE_OPERAND (base
, 0));
348 else if (DECL_P (base
))
349 return ptr_deref_may_alias_decl_p (ptr
, base
);
354 /* Returns true if PTR1 and PTR2 compare unequal because of points-to. */
357 ptrs_compare_unequal (tree ptr1
, tree ptr2
)
359 /* First resolve the pointers down to a SSA name pointer base or
360 a VAR_DECL, PARM_DECL or RESULT_DECL. This explicitely does
361 not yet try to handle LABEL_DECLs, FUNCTION_DECLs, CONST_DECLs
362 or STRING_CSTs which needs points-to adjustments to track them
363 in the points-to sets. */
364 tree obj1
= NULL_TREE
;
365 tree obj2
= NULL_TREE
;
366 if (TREE_CODE (ptr1
) == ADDR_EXPR
)
368 tree tem
= get_base_address (TREE_OPERAND (ptr1
, 0));
372 || TREE_CODE (tem
) == PARM_DECL
373 || TREE_CODE (tem
) == RESULT_DECL
)
375 else if (TREE_CODE (tem
) == MEM_REF
)
376 ptr1
= TREE_OPERAND (tem
, 0);
378 if (TREE_CODE (ptr2
) == ADDR_EXPR
)
380 tree tem
= get_base_address (TREE_OPERAND (ptr2
, 0));
384 || TREE_CODE (tem
) == PARM_DECL
385 || TREE_CODE (tem
) == RESULT_DECL
)
387 else if (TREE_CODE (tem
) == MEM_REF
)
388 ptr2
= TREE_OPERAND (tem
, 0);
391 /* Canonicalize ptr vs. object. */
392 if (TREE_CODE (ptr1
) == SSA_NAME
&& obj2
)
394 std::swap (ptr1
, ptr2
);
395 std::swap (obj1
, obj2
);
399 /* Other code handles this correctly, no need to duplicate it here. */;
400 else if (obj1
&& TREE_CODE (ptr2
) == SSA_NAME
)
402 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (ptr2
);
403 /* We may not use restrict to optimize pointer comparisons.
404 See PR71062. So we have to assume that restrict-pointed-to
405 may be in fact obj1. */
407 || pi
->pt
.vars_contains_restrict
408 || pi
->pt
.vars_contains_interposable
)
411 && (TREE_STATIC (obj1
) || DECL_EXTERNAL (obj1
)))
413 varpool_node
*node
= varpool_node::get (obj1
);
414 /* If obj1 may bind to NULL give up (see below). */
416 || ! node
->nonzero_address ()
417 || ! decl_binds_to_current_def_p (obj1
))
420 return !pt_solution_includes (&pi
->pt
, obj1
);
423 /* ??? We'd like to handle ptr1 != NULL and ptr1 != ptr2
424 but those require pt.null to be conservatively correct. */
429 /* Returns whether reference REF to BASE may refer to global memory. */
432 ref_may_alias_global_p_1 (tree base
)
435 return is_global_var (base
);
436 else if (TREE_CODE (base
) == MEM_REF
437 || TREE_CODE (base
) == TARGET_MEM_REF
)
438 return ptr_deref_may_alias_global_p (TREE_OPERAND (base
, 0));
443 ref_may_alias_global_p (ao_ref
*ref
)
445 tree base
= ao_ref_base (ref
);
446 return ref_may_alias_global_p_1 (base
);
450 ref_may_alias_global_p (tree ref
)
452 tree base
= get_base_address (ref
);
453 return ref_may_alias_global_p_1 (base
);
456 /* Return true whether STMT may clobber global memory. */
459 stmt_may_clobber_global_p (gimple
*stmt
)
463 if (!gimple_vdef (stmt
))
466 /* ??? We can ask the oracle whether an artificial pointer
467 dereference with a pointer with points-to information covering
468 all global memory (what about non-address taken memory?) maybe
469 clobbered by this call. As there is at the moment no convenient
470 way of doing that without generating garbage do some manual
472 ??? We could make a NULL ao_ref argument to the various
473 predicates special, meaning any global memory. */
475 switch (gimple_code (stmt
))
478 lhs
= gimple_assign_lhs (stmt
);
479 return (TREE_CODE (lhs
) != SSA_NAME
480 && ref_may_alias_global_p (lhs
));
489 /* Dump alias information on FILE. */
492 dump_alias_info (FILE *file
)
497 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
500 fprintf (file
, "\n\nAlias information for %s\n\n", funcname
);
502 fprintf (file
, "Aliased symbols\n\n");
504 FOR_EACH_LOCAL_DECL (cfun
, i
, var
)
506 if (may_be_aliased (var
))
507 dump_variable (file
, var
);
510 fprintf (file
, "\nCall clobber information\n");
512 fprintf (file
, "\nESCAPED");
513 dump_points_to_solution (file
, &cfun
->gimple_df
->escaped
);
515 fprintf (file
, "\n\nFlow-insensitive points-to information\n\n");
517 FOR_EACH_SSA_NAME (i
, ptr
, cfun
)
519 struct ptr_info_def
*pi
;
521 if (!POINTER_TYPE_P (TREE_TYPE (ptr
))
522 || SSA_NAME_IN_FREE_LIST (ptr
))
525 pi
= SSA_NAME_PTR_INFO (ptr
);
527 dump_points_to_info_for (file
, ptr
);
530 fprintf (file
, "\n");
534 /* Dump alias information on stderr. */
537 debug_alias_info (void)
539 dump_alias_info (stderr
);
543 /* Dump the points-to set *PT into FILE. */
546 dump_points_to_solution (FILE *file
, struct pt_solution
*pt
)
549 fprintf (file
, ", points-to anything");
552 fprintf (file
, ", points-to non-local");
555 fprintf (file
, ", points-to escaped");
558 fprintf (file
, ", points-to unit escaped");
561 fprintf (file
, ", points-to NULL");
565 fprintf (file
, ", points-to vars: ");
566 dump_decl_set (file
, pt
->vars
);
567 if (pt
->vars_contains_nonlocal
568 || pt
->vars_contains_escaped
569 || pt
->vars_contains_escaped_heap
570 || pt
->vars_contains_restrict
)
572 const char *comma
= "";
573 fprintf (file
, " (");
574 if (pt
->vars_contains_nonlocal
)
576 fprintf (file
, "nonlocal");
579 if (pt
->vars_contains_escaped
)
581 fprintf (file
, "%sescaped", comma
);
584 if (pt
->vars_contains_escaped_heap
)
586 fprintf (file
, "%sescaped heap", comma
);
589 if (pt
->vars_contains_restrict
)
591 fprintf (file
, "%srestrict", comma
);
594 if (pt
->vars_contains_interposable
)
595 fprintf (file
, "%sinterposable", comma
);
602 /* Unified dump function for pt_solution. */
605 debug (pt_solution
&ref
)
607 dump_points_to_solution (stderr
, &ref
);
611 debug (pt_solution
*ptr
)
616 fprintf (stderr
, "<nil>\n");
620 /* Dump points-to information for SSA_NAME PTR into FILE. */
623 dump_points_to_info_for (FILE *file
, tree ptr
)
625 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (ptr
);
627 print_generic_expr (file
, ptr
, dump_flags
);
630 dump_points_to_solution (file
, &pi
->pt
);
632 fprintf (file
, ", points-to anything");
634 fprintf (file
, "\n");
638 /* Dump points-to information for VAR into stderr. */
641 debug_points_to_info_for (tree var
)
643 dump_points_to_info_for (stderr
, var
);
647 /* Initializes the alias-oracle reference representation *R from REF. */
650 ao_ref_init (ao_ref
*r
, tree ref
)
657 r
->ref_alias_set
= -1;
658 r
->base_alias_set
= -1;
659 r
->volatile_p
= ref
? TREE_THIS_VOLATILE (ref
) : false;
662 /* Returns the base object of the memory reference *REF. */
665 ao_ref_base (ao_ref
*ref
)
671 ref
->base
= get_ref_base_and_extent (ref
->ref
, &ref
->offset
, &ref
->size
,
672 &ref
->max_size
, &reverse
);
676 /* Returns the base object alias set of the memory reference *REF. */
679 ao_ref_base_alias_set (ao_ref
*ref
)
682 if (ref
->base_alias_set
!= -1)
683 return ref
->base_alias_set
;
687 while (handled_component_p (base_ref
))
688 base_ref
= TREE_OPERAND (base_ref
, 0);
689 ref
->base_alias_set
= get_alias_set (base_ref
);
690 return ref
->base_alias_set
;
693 /* Returns the reference alias set of the memory reference *REF. */
696 ao_ref_alias_set (ao_ref
*ref
)
698 if (ref
->ref_alias_set
!= -1)
699 return ref
->ref_alias_set
;
700 ref
->ref_alias_set
= get_alias_set (ref
->ref
);
701 return ref
->ref_alias_set
;
704 /* Init an alias-oracle reference representation from a gimple pointer
705 PTR and a gimple size SIZE in bytes. If SIZE is NULL_TREE then the
706 size is assumed to be unknown. The access is assumed to be only
707 to or after of the pointer target, not before it. */
710 ao_ref_init_from_ptr_and_size (ao_ref
*ref
, tree ptr
, tree size
)
712 poly_int64 t
, size_hwi
, extra_offset
= 0;
713 ref
->ref
= NULL_TREE
;
714 if (TREE_CODE (ptr
) == SSA_NAME
)
716 gimple
*stmt
= SSA_NAME_DEF_STMT (ptr
);
717 if (gimple_assign_single_p (stmt
)
718 && gimple_assign_rhs_code (stmt
) == ADDR_EXPR
)
719 ptr
= gimple_assign_rhs1 (stmt
);
720 else if (is_gimple_assign (stmt
)
721 && gimple_assign_rhs_code (stmt
) == POINTER_PLUS_EXPR
722 && ptrdiff_tree_p (gimple_assign_rhs2 (stmt
), &extra_offset
))
724 ptr
= gimple_assign_rhs1 (stmt
);
725 extra_offset
*= BITS_PER_UNIT
;
729 if (TREE_CODE (ptr
) == ADDR_EXPR
)
731 ref
->base
= get_addr_base_and_unit_offset (TREE_OPERAND (ptr
, 0), &t
);
733 ref
->offset
= BITS_PER_UNIT
* t
;
738 ref
->base
= get_base_address (TREE_OPERAND (ptr
, 0));
743 gcc_assert (POINTER_TYPE_P (TREE_TYPE (ptr
)));
744 ref
->base
= build2 (MEM_REF
, char_type_node
,
745 ptr
, null_pointer_node
);
748 ref
->offset
+= extra_offset
;
750 && poly_int_tree_p (size
, &size_hwi
)
751 && coeffs_in_range_p (size_hwi
, 0, HOST_WIDE_INT_MAX
/ BITS_PER_UNIT
))
752 ref
->max_size
= ref
->size
= size_hwi
* BITS_PER_UNIT
;
754 ref
->max_size
= ref
->size
= -1;
755 ref
->ref_alias_set
= 0;
756 ref
->base_alias_set
= 0;
757 ref
->volatile_p
= false;
760 /* S1 and S2 are TYPE_SIZE or DECL_SIZE. Compare them:
763 Return 0 if equal or incomparable. */
766 compare_sizes (tree s1
, tree s2
)
774 if (!poly_int_tree_p (s1
, &size1
) || !poly_int_tree_p (s2
, &size2
))
776 if (known_lt (size1
, size2
))
778 if (known_lt (size2
, size1
))
783 /* Compare TYPE1 and TYPE2 by its size.
784 Return -1 if size of TYPE1 < size of TYPE2
785 Return 1 if size of TYPE1 > size of TYPE2
786 Return 0 if types are of equal sizes or we can not compare them. */
789 compare_type_sizes (tree type1
, tree type2
)
791 /* Be conservative for arrays and vectors. We want to support partial
792 overlap on int[3] and int[3] as tested in gcc.dg/torture/alias-2.c. */
793 while (TREE_CODE (type1
) == ARRAY_TYPE
794 || TREE_CODE (type1
) == VECTOR_TYPE
)
795 type1
= TREE_TYPE (type1
);
796 while (TREE_CODE (type2
) == ARRAY_TYPE
797 || TREE_CODE (type2
) == VECTOR_TYPE
)
798 type2
= TREE_TYPE (type2
);
799 return compare_sizes (TYPE_SIZE (type1
), TYPE_SIZE (type2
));
802 /* Return 1 if TYPE1 and TYPE2 are to be considered equivalent for the
803 purpose of TBAA. Return 0 if they are distinct and -1 if we cannot
807 same_type_for_tbaa (tree type1
, tree type2
)
809 type1
= TYPE_MAIN_VARIANT (type1
);
810 type2
= TYPE_MAIN_VARIANT (type2
);
812 /* Handle the most common case first. */
816 /* If we would have to do structural comparison bail out. */
817 if (TYPE_STRUCTURAL_EQUALITY_P (type1
)
818 || TYPE_STRUCTURAL_EQUALITY_P (type2
))
821 /* Compare the canonical types. */
822 if (TYPE_CANONICAL (type1
) == TYPE_CANONICAL (type2
))
825 /* ??? Array types are not properly unified in all cases as we have
826 spurious changes in the index types for example. Removing this
827 causes all sorts of problems with the Fortran frontend. */
828 if (TREE_CODE (type1
) == ARRAY_TYPE
829 && TREE_CODE (type2
) == ARRAY_TYPE
)
832 /* ??? In Ada, an lvalue of an unconstrained type can be used to access an
833 object of one of its constrained subtypes, e.g. when a function with an
834 unconstrained parameter passed by reference is called on an object and
835 inlined. But, even in the case of a fixed size, type and subtypes are
836 not equivalent enough as to share the same TYPE_CANONICAL, since this
837 would mean that conversions between them are useless, whereas they are
838 not (e.g. type and subtypes can have different modes). So, in the end,
839 they are only guaranteed to have the same alias set. */
840 if (get_alias_set (type1
) == get_alias_set (type2
))
843 /* The types are known to be not equal. */
847 /* Return true if TYPE is a composite type (i.e. we may apply one of handled
848 components on it). */
851 type_has_components_p (tree type
)
853 return AGGREGATE_TYPE_P (type
) || VECTOR_TYPE_P (type
)
854 || TREE_CODE (type
) == COMPLEX_TYPE
;
857 /* MATCH1 and MATCH2 which are part of access path of REF1 and REF2
858 respectively are either pointing to same address or are completely
861 Try to disambiguate using the access path starting from the match
862 and return false if there is no conflict.
864 Helper for aliasing_component_refs_p. */
867 aliasing_matching_component_refs_p (tree match1
, tree ref1
,
868 poly_int64 offset1
, poly_int64 max_size1
,
869 tree match2
, tree ref2
,
870 poly_int64 offset2
, poly_int64 max_size2
)
872 poly_int64 offadj
, sztmp
, msztmp
;
876 get_ref_base_and_extent (match2
, &offadj
, &sztmp
, &msztmp
, &reverse
);
878 get_ref_base_and_extent (match1
, &offadj
, &sztmp
, &msztmp
, &reverse
);
880 if (!ranges_maybe_overlap_p (offset1
, max_size1
, offset2
, max_size2
))
882 ++alias_stats
.aliasing_component_refs_p_no_alias
;
886 int cmp
= nonoverlapping_component_refs_since_match_p (match1
, ref1
,
889 || (cmp
== -1 && nonoverlapping_component_refs_p (ref1
, ref2
)))
891 ++alias_stats
.aliasing_component_refs_p_no_alias
;
894 ++alias_stats
.aliasing_component_refs_p_may_alias
;
898 /* Determine if the two component references REF1 and REF2 which are
899 based on access types TYPE1 and TYPE2 and of which at least one is based
900 on an indirect reference may alias.
901 REF1_ALIAS_SET, BASE1_ALIAS_SET, REF2_ALIAS_SET and BASE2_ALIAS_SET
902 are the respective alias sets. */
905 aliasing_component_refs_p (tree ref1
,
906 alias_set_type ref1_alias_set
,
907 alias_set_type base1_alias_set
,
908 poly_int64 offset1
, poly_int64 max_size1
,
910 alias_set_type ref2_alias_set
,
911 alias_set_type base2_alias_set
,
912 poly_int64 offset2
, poly_int64 max_size2
)
914 /* If one reference is a component references through pointers try to find a
915 common base and apply offset based disambiguation. This handles
917 struct A { int i; int j; } *q;
918 struct B { struct A a; int k; } *p;
919 disambiguating q->i and p->a.j. */
922 int same_p1
= 0, same_p2
= 0;
923 bool maybe_match
= false;
924 tree end_struct_ref1
= NULL
, end_struct_ref2
= NULL
;
926 /* Choose bases and base types to search for. */
928 while (handled_component_p (base1
))
930 /* Generally access paths are monotous in the size of object. The
931 exception are trailing arrays of structures. I.e.
932 struct a {int array[0];};
934 struct a {int array1[0]; int array[];};
935 Such struct has size 0 but accesses to a.array may have non-zero size.
936 In this case the size of TREE_TYPE (base1) is smaller than
937 size of TREE_TYPE (TREE_OPERNAD (base1, 0)).
939 Because we compare sizes of arrays just by sizes of their elements,
940 we only need to care about zero sized array fields here. */
941 if (TREE_CODE (base1
) == COMPONENT_REF
942 && TREE_CODE (TREE_TYPE (TREE_OPERAND (base1
, 1))) == ARRAY_TYPE
943 && (!TYPE_SIZE (TREE_TYPE (TREE_OPERAND (base1
, 1)))
944 || integer_zerop (TYPE_SIZE (TREE_TYPE (TREE_OPERAND (base1
, 1)))))
945 && array_at_struct_end_p (base1
))
947 gcc_checking_assert (!end_struct_ref1
);
948 end_struct_ref1
= base1
;
950 if (TREE_CODE (base1
) == VIEW_CONVERT_EXPR
951 || TREE_CODE (base1
) == BIT_FIELD_REF
)
952 ref1
= TREE_OPERAND (base1
, 0);
953 base1
= TREE_OPERAND (base1
, 0);
955 type1
= TREE_TYPE (base1
);
957 while (handled_component_p (base2
))
959 if (TREE_CODE (base2
) == COMPONENT_REF
960 && TREE_CODE (TREE_TYPE (TREE_OPERAND (base2
, 1))) == ARRAY_TYPE
961 && (!TYPE_SIZE (TREE_TYPE (TREE_OPERAND (base2
, 1)))
962 || integer_zerop (TYPE_SIZE (TREE_TYPE (TREE_OPERAND (base2
, 1)))))
963 && array_at_struct_end_p (base2
))
965 gcc_checking_assert (!end_struct_ref2
);
966 end_struct_ref2
= base2
;
968 if (TREE_CODE (base2
) == VIEW_CONVERT_EXPR
969 || TREE_CODE (base2
) == BIT_FIELD_REF
)
970 ref2
= TREE_OPERAND (base2
, 0);
971 base2
= TREE_OPERAND (base2
, 0);
973 type2
= TREE_TYPE (base2
);
975 /* Now search for the type1 in the access path of ref2. This
976 would be a common base for doing offset based disambiguation on.
977 This however only makes sense if type2 is big enough to hold type1. */
978 int cmp_outer
= compare_type_sizes (type2
, type1
);
980 /* If type2 is big enough to contain type1 walk its access path.
981 We also need to care of arrays at the end of structs that may extend
982 beyond the end of structure. */
985 && compare_type_sizes (TREE_TYPE (end_struct_ref2
), type1
) >= 0))
990 /* We walk from inner type to the outer types. If type we see is
991 already too large to be part of type1, terminate the search. */
992 int cmp
= compare_type_sizes (type1
, TREE_TYPE (ref
));
996 || compare_type_sizes (TREE_TYPE (end_struct_ref1
),
997 TREE_TYPE (ref
)) < 0))
999 /* If types may be of same size, see if we can decide about their
1003 same_p2
= same_type_for_tbaa (TREE_TYPE (ref
), type1
);
1006 /* In case we can't decide whether types are same try to
1007 continue looking for the exact match.
1008 Remember however that we possibly saw a match
1009 to bypass the access path continuations tests we do later. */
1013 if (!handled_component_p (ref
))
1015 ref
= TREE_OPERAND (ref
, 0);
1019 /* We assume that arrays can overlap by multiple of their elements
1020 size as tested in gcc.dg/torture/alias-2.c.
1021 This partial overlap happen only when both arrays are bases of
1022 the access and not contained within another component ref.
1023 To be safe we also assume partial overlap for VLAs. */
1024 if (TREE_CODE (TREE_TYPE (base1
)) == ARRAY_TYPE
1025 && (!TYPE_SIZE (TREE_TYPE (base1
))
1026 || TREE_CODE (TYPE_SIZE (TREE_TYPE (base1
))) != INTEGER_CST
1028 /* Setting maybe_match to true triggers
1029 nonoverlapping_component_refs_p test later that still may do
1030 useful disambiguation. */
1033 return aliasing_matching_component_refs_p (base1
, ref1
,
1036 offset2
, max_size2
);
1040 /* If we didn't find a common base, try the other way around. */
1043 && compare_type_sizes (TREE_TYPE (end_struct_ref1
), type1
) <= 0))
1048 int cmp
= compare_type_sizes (type2
, TREE_TYPE (ref
));
1050 && (!end_struct_ref2
1051 || compare_type_sizes (TREE_TYPE (end_struct_ref2
),
1052 TREE_TYPE (ref
)) < 0))
1054 /* If types may be of same size, see if we can decide about their
1058 same_p1
= same_type_for_tbaa (TREE_TYPE (ref
), type2
);
1064 if (!handled_component_p (ref
))
1066 ref
= TREE_OPERAND (ref
, 0);
1070 if (TREE_CODE (TREE_TYPE (base2
)) == ARRAY_TYPE
1071 && (!TYPE_SIZE (TREE_TYPE (base2
))
1072 || TREE_CODE (TYPE_SIZE (TREE_TYPE (base2
))) != INTEGER_CST
1076 return aliasing_matching_component_refs_p (ref
, ref1
,
1079 offset2
, max_size2
);
1083 /* In the following code we make an assumption that the types in access
1084 paths do not overlap and thus accesses alias only if one path can be
1085 continuation of another. If we was not able to decide about equivalence,
1086 we need to give up. */
1089 if (!nonoverlapping_component_refs_p (ref1
, ref2
))
1091 ++alias_stats
.aliasing_component_refs_p_may_alias
;
1094 ++alias_stats
.aliasing_component_refs_p_no_alias
;
1098 /* If we have two type access paths B1.path1 and B2.path2 they may
1099 only alias if either B1 is in B2.path2 or B2 is in B1.path1.
1100 But we can still have a path that goes B1.path1...B2.path2 with
1101 a part that we do not see. So we can only disambiguate now
1102 if there is no B2 in the tail of path1 and no B1 on the
1104 if (compare_type_sizes (TREE_TYPE (ref2
), type1
) >= 0
1105 && (!end_struct_ref1
1106 || compare_type_sizes (TREE_TYPE (ref2
),
1107 TREE_TYPE (end_struct_ref1
)) >= 0)
1108 && type_has_components_p (TREE_TYPE (ref2
))
1109 && (base1_alias_set
== ref2_alias_set
1110 || alias_set_subset_of (base1_alias_set
, ref2_alias_set
)))
1112 ++alias_stats
.aliasing_component_refs_p_may_alias
;
1115 /* If this is ptr vs. decl then we know there is no ptr ... decl path. */
1116 if (compare_type_sizes (TREE_TYPE (ref1
), type2
) >= 0
1117 && (!end_struct_ref2
1118 || compare_type_sizes (TREE_TYPE (ref1
),
1119 TREE_TYPE (end_struct_ref2
)) >= 0)
1120 && type_has_components_p (TREE_TYPE (ref1
))
1121 && (base2_alias_set
== ref1_alias_set
1122 || alias_set_subset_of (base2_alias_set
, ref1_alias_set
)))
1124 ++alias_stats
.aliasing_component_refs_p_may_alias
;
1127 ++alias_stats
.aliasing_component_refs_p_no_alias
;
1131 /* FIELD1 and FIELD2 are two fields of component refs. We assume
1132 that bases of both component refs are either equivalent or nonoverlapping.
1133 We do not assume that the containers of FIELD1 and FIELD2 are of the
1136 Return 0 in case the base address of component_refs are same then
1137 FIELD1 and FIELD2 have same address. Note that FIELD1 and FIELD2
1138 may not be of same type or size.
1140 Return 1 if FIELD1 and FIELD2 are non-overlapping.
1142 Return -1 otherwise.
1144 Main difference between 0 and -1 is to let
1145 nonoverlapping_component_refs_since_match_p discover the semantically
1146 equivalent part of the access path.
1148 Note that this function is used even with -fno-strict-aliasing
1149 and makes use of no TBAA assumptions. */
1152 nonoverlapping_component_refs_p_1 (const_tree field1
, const_tree field2
)
1154 /* If both fields are of the same type, we could save hard work of
1155 comparing offsets. */
1156 tree type1
= DECL_CONTEXT (field1
);
1157 tree type2
= DECL_CONTEXT (field2
);
1159 if (TREE_CODE (type1
) == RECORD_TYPE
1160 && DECL_BIT_FIELD_REPRESENTATIVE (field1
))
1161 field1
= DECL_BIT_FIELD_REPRESENTATIVE (field1
);
1162 if (TREE_CODE (type2
) == RECORD_TYPE
1163 && DECL_BIT_FIELD_REPRESENTATIVE (field2
))
1164 field2
= DECL_BIT_FIELD_REPRESENTATIVE (field2
);
1166 /* ??? Bitfields can overlap at RTL level so punt on them.
1167 FIXME: RTL expansion should be fixed by adjusting the access path
1168 when producing MEM_ATTRs for MEMs which are wider than
1169 the bitfields similarly as done in set_mem_attrs_minus_bitpos. */
1170 if (DECL_BIT_FIELD (field1
) && DECL_BIT_FIELD (field2
))
1173 /* Assume that different FIELD_DECLs never overlap within a RECORD_TYPE. */
1174 if (type1
== type2
&& TREE_CODE (type1
) == RECORD_TYPE
)
1175 return field1
!= field2
;
1177 /* In common case the offsets and bit offsets will be the same.
1178 However if frontends do not agree on the alignment, they may be
1179 different even if they actually represent same address.
1180 Try the common case first and if that fails calcualte the
1181 actual bit offset. */
1182 if (tree_int_cst_equal (DECL_FIELD_OFFSET (field1
),
1183 DECL_FIELD_OFFSET (field2
))
1184 && tree_int_cst_equal (DECL_FIELD_BIT_OFFSET (field1
),
1185 DECL_FIELD_BIT_OFFSET (field2
)))
1188 /* Note that it may be possible to use component_ref_field_offset
1189 which would provide offsets as trees. However constructing and folding
1190 trees is expensive and does not seem to be worth the compile time
1193 poly_uint64 offset1
, offset2
;
1194 poly_uint64 bit_offset1
, bit_offset2
;
1196 if (poly_int_tree_p (DECL_FIELD_OFFSET (field1
), &offset1
)
1197 && poly_int_tree_p (DECL_FIELD_OFFSET (field2
), &offset2
)
1198 && poly_int_tree_p (DECL_FIELD_BIT_OFFSET (field1
), &bit_offset1
)
1199 && poly_int_tree_p (DECL_FIELD_BIT_OFFSET (field2
), &bit_offset2
))
1201 offset1
= (offset1
<< LOG2_BITS_PER_UNIT
) + bit_offset1
;
1202 offset2
= (offset2
<< LOG2_BITS_PER_UNIT
) + bit_offset2
;
1204 if (known_eq (offset1
, offset2
))
1207 poly_uint64 size1
, size2
;
1209 if (poly_int_tree_p (DECL_SIZE (field1
), &size1
)
1210 && poly_int_tree_p (DECL_SIZE (field2
), &size2
)
1211 && !ranges_maybe_overlap_p (offset1
, size1
, offset2
, size2
))
1214 /* Resort to slower overlap checking by looking for matching types in
1215 the middle of access path. */
1219 /* Try to disambiguate REF1 and REF2 under the assumption that MATCH1 and
1220 MATCH2 either point to the same address or are disjoint.
1221 MATCH1 and MATCH2 are assumed to be ref in the access path of REF1 and REF2
1222 respectively or NULL in the case we established equivalence of bases.
1224 This test works by matching the initial segment of the access path
1225 and does not rely on TBAA thus is safe for !flag_strict_aliasing if
1226 match was determined without use of TBAA oracle.
1228 Return 1 if we can determine that component references REF1 and REF2,
1229 that are within a common DECL, cannot overlap.
1231 Return 0 if paths are same and thus there is nothing to disambiguate more
1232 (i.e. there is must alias assuming there is must alias between MATCH1 and
1235 Return -1 if we can not determine 0 or 1 - this happens when we met
1236 non-matching types was met in the path.
1237 In this case it may make sense to continue by other disambiguation
1241 nonoverlapping_component_refs_since_match_p (tree match1
, tree ref1
,
1242 tree match2
, tree ref2
)
1244 /* Early return if there are no references to match, we do not need
1245 to walk the access paths.
1247 Do not consider this as may-alias for stats - it is more useful
1248 to have information how many disambiguations happened provided that
1249 the query was meaningful. */
1251 if (match1
== ref1
|| !handled_component_p (ref1
)
1252 || match2
== ref2
|| !handled_component_p (ref2
))
1255 auto_vec
<tree
, 16> component_refs1
;
1256 auto_vec
<tree
, 16> component_refs2
;
1258 /* Create the stack of handled components for REF1. */
1259 while (handled_component_p (ref1
) && ref1
!= match1
)
1261 if (TREE_CODE (ref1
) == VIEW_CONVERT_EXPR
1262 || TREE_CODE (ref1
) == BIT_FIELD_REF
)
1263 component_refs1
.truncate (0);
1265 component_refs1
.safe_push (ref1
);
1266 ref1
= TREE_OPERAND (ref1
, 0);
1269 /* Create the stack of handled components for REF2. */
1270 while (handled_component_p (ref2
) && ref2
!= match2
)
1272 if (TREE_CODE (ref2
) == VIEW_CONVERT_EXPR
1273 || TREE_CODE (ref2
) == BIT_FIELD_REF
)
1274 component_refs2
.truncate (0);
1276 component_refs2
.safe_push (ref2
);
1277 ref2
= TREE_OPERAND (ref2
, 0);
1280 bool mem_ref1
= TREE_CODE (ref1
) == MEM_REF
&& ref1
!= match1
;
1281 bool mem_ref2
= TREE_CODE (ref2
) == MEM_REF
&& ref2
!= match2
;
1283 /* If only one of access path starts with MEM_REF check that offset is 0
1284 so the addresses stays the same after stripping it.
1285 TODO: In this case we may walk the other access path until we get same
1288 If both starts with MEM_REF, offset has to be same. */
1289 if ((mem_ref1
&& !mem_ref2
&& !integer_zerop (TREE_OPERAND (ref1
, 1)))
1290 || (mem_ref2
&& !mem_ref1
&& !integer_zerop (TREE_OPERAND (ref2
, 1)))
1291 || (mem_ref1
&& mem_ref2
1292 && !tree_int_cst_equal (TREE_OPERAND (ref1
, 1),
1293 TREE_OPERAND (ref2
, 1))))
1295 ++alias_stats
.nonoverlapping_component_refs_since_match_p_may_alias
;
1299 /* TARGET_MEM_REF are never wrapped in handled components, so we do not need
1300 to handle them here at all. */
1301 gcc_checking_assert (TREE_CODE (ref1
) != TARGET_MEM_REF
1302 && TREE_CODE (ref2
) != TARGET_MEM_REF
);
1304 /* Pop the stacks in parallel and examine the COMPONENT_REFs of the same
1305 rank. This is sufficient because we start from the same DECL and you
1306 cannot reference several fields at a time with COMPONENT_REFs (unlike
1307 with ARRAY_RANGE_REFs for arrays) so you always need the same number
1308 of them to access a sub-component, unless you're in a union, in which
1309 case the return value will precisely be false. */
1312 bool seen_noncomponent_ref_p
= false;
1315 if (component_refs1
.is_empty ())
1318 .nonoverlapping_component_refs_since_match_p_must_overlap
;
1321 ref1
= component_refs1
.pop ();
1322 if (TREE_CODE (ref1
) != COMPONENT_REF
)
1323 seen_noncomponent_ref_p
= true;
1325 while (!RECORD_OR_UNION_TYPE_P (TREE_TYPE (TREE_OPERAND (ref1
, 0))));
1329 if (component_refs2
.is_empty ())
1332 .nonoverlapping_component_refs_since_match_p_must_overlap
;
1335 ref2
= component_refs2
.pop ();
1336 if (TREE_CODE (ref2
) != COMPONENT_REF
)
1337 seen_noncomponent_ref_p
= true;
1339 while (!RECORD_OR_UNION_TYPE_P (TREE_TYPE (TREE_OPERAND (ref2
, 0))));
1341 /* BIT_FIELD_REF and VIEW_CONVERT_EXPR are taken off the vectors
1343 gcc_checking_assert (TREE_CODE (ref1
) == COMPONENT_REF
1344 && TREE_CODE (ref2
) == COMPONENT_REF
);
1346 tree field1
= TREE_OPERAND (ref1
, 1);
1347 tree field2
= TREE_OPERAND (ref2
, 1);
1349 /* ??? We cannot simply use the type of operand #0 of the refs here
1350 as the Fortran compiler smuggles type punning into COMPONENT_REFs
1351 for common blocks instead of using unions like everyone else. */
1352 tree type1
= DECL_CONTEXT (field1
);
1353 tree type2
= DECL_CONTEXT (field2
);
1355 /* If we skipped array refs on type of different sizes, we can
1356 no longer be sure that there are not partial overlaps. */
1357 if (seen_noncomponent_ref_p
1358 && !operand_equal_p (TYPE_SIZE (type1
), TYPE_SIZE (type2
), 0))
1361 .nonoverlapping_component_refs_since_match_p_may_alias
;
1365 int cmp
= nonoverlapping_component_refs_p_1 (field1
, field2
);
1369 .nonoverlapping_component_refs_since_match_p_may_alias
;
1375 .nonoverlapping_component_refs_since_match_p_no_alias
;
1380 ++alias_stats
.nonoverlapping_component_refs_since_match_p_must_overlap
;
1384 /* Return TYPE_UID which can be used to match record types we consider
1385 same for TBAA purposes. */
1388 ncr_type_uid (const_tree field
)
1390 /* ??? We cannot simply use the type of operand #0 of the refs here
1391 as the Fortran compiler smuggles type punning into COMPONENT_REFs
1392 for common blocks instead of using unions like everyone else. */
1393 tree type
= DECL_FIELD_CONTEXT (field
);
1394 /* With LTO types considered same_type_for_tbaa_p
1395 from different translation unit may not have same
1396 main variant. They however have same TYPE_CANONICAL. */
1397 if (TYPE_CANONICAL (type
))
1398 return TYPE_UID (TYPE_CANONICAL (type
));
1399 return TYPE_UID (type
);
1402 /* qsort compare function to sort FIELD_DECLs after their
1403 DECL_FIELD_CONTEXT TYPE_UID. */
1406 ncr_compar (const void *field1_
, const void *field2_
)
1408 const_tree field1
= *(const_tree
*) const_cast <void *>(field1_
);
1409 const_tree field2
= *(const_tree
*) const_cast <void *>(field2_
);
1410 unsigned int uid1
= ncr_type_uid (field1
);
1411 unsigned int uid2
= ncr_type_uid (field2
);
1415 else if (uid1
> uid2
)
1420 /* Return true if we can determine that the fields referenced cannot
1421 overlap for any pair of objects. This relies on TBAA. */
1424 nonoverlapping_component_refs_p (const_tree x
, const_tree y
)
1426 /* Early return if we have nothing to do.
1428 Do not consider this as may-alias for stats - it is more useful
1429 to have information how many disambiguations happened provided that
1430 the query was meaningful. */
1431 if (!flag_strict_aliasing
1433 || !handled_component_p (x
)
1434 || !handled_component_p (y
))
1437 auto_vec
<const_tree
, 16> fieldsx
;
1438 while (handled_component_p (x
))
1440 if (TREE_CODE (x
) == COMPONENT_REF
)
1442 tree field
= TREE_OPERAND (x
, 1);
1443 tree type
= DECL_FIELD_CONTEXT (field
);
1444 if (TREE_CODE (type
) == RECORD_TYPE
)
1445 fieldsx
.safe_push (field
);
1447 else if (TREE_CODE (x
) == VIEW_CONVERT_EXPR
1448 || TREE_CODE (x
) == BIT_FIELD_REF
)
1449 fieldsx
.truncate (0);
1450 x
= TREE_OPERAND (x
, 0);
1452 if (fieldsx
.length () == 0)
1454 auto_vec
<const_tree
, 16> fieldsy
;
1455 while (handled_component_p (y
))
1457 if (TREE_CODE (y
) == COMPONENT_REF
)
1459 tree field
= TREE_OPERAND (y
, 1);
1460 tree type
= DECL_FIELD_CONTEXT (field
);
1461 if (TREE_CODE (type
) == RECORD_TYPE
)
1462 fieldsy
.safe_push (TREE_OPERAND (y
, 1));
1464 else if (TREE_CODE (y
) == VIEW_CONVERT_EXPR
1465 || TREE_CODE (y
) == BIT_FIELD_REF
)
1466 fieldsy
.truncate (0);
1467 y
= TREE_OPERAND (y
, 0);
1469 if (fieldsy
.length () == 0)
1471 ++alias_stats
.nonoverlapping_component_refs_p_may_alias
;
1475 /* Most common case first. */
1476 if (fieldsx
.length () == 1
1477 && fieldsy
.length () == 1)
1479 if (same_type_for_tbaa (DECL_FIELD_CONTEXT (fieldsx
[0]),
1480 DECL_FIELD_CONTEXT (fieldsy
[0])) == 1
1481 && nonoverlapping_component_refs_p_1 (fieldsx
[0], fieldsy
[0]) == 1)
1483 ++alias_stats
.nonoverlapping_component_refs_p_no_alias
;
1488 ++alias_stats
.nonoverlapping_component_refs_p_may_alias
;
1493 if (fieldsx
.length () == 2)
1495 if (ncr_compar (&fieldsx
[0], &fieldsx
[1]) == 1)
1496 std::swap (fieldsx
[0], fieldsx
[1]);
1499 fieldsx
.qsort (ncr_compar
);
1501 if (fieldsy
.length () == 2)
1503 if (ncr_compar (&fieldsy
[0], &fieldsy
[1]) == 1)
1504 std::swap (fieldsy
[0], fieldsy
[1]);
1507 fieldsy
.qsort (ncr_compar
);
1509 unsigned i
= 0, j
= 0;
1512 const_tree fieldx
= fieldsx
[i
];
1513 const_tree fieldy
= fieldsy
[j
];
1515 /* We're left with accessing different fields of a structure,
1516 no possible overlap. */
1517 if (same_type_for_tbaa (DECL_FIELD_CONTEXT (fieldx
),
1518 DECL_FIELD_CONTEXT (fieldy
)) == 1
1519 && nonoverlapping_component_refs_p_1 (fieldx
, fieldy
) == 1)
1521 ++alias_stats
.nonoverlapping_component_refs_p_no_alias
;
1525 if (ncr_type_uid (fieldx
) < ncr_type_uid (fieldy
))
1528 if (i
== fieldsx
.length ())
1534 if (j
== fieldsy
.length ())
1540 ++alias_stats
.nonoverlapping_component_refs_p_may_alias
;
1545 /* Return true if two memory references based on the variables BASE1
1546 and BASE2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and
1547 [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. REF1 and REF2
1548 if non-NULL are the complete memory reference trees. */
1551 decl_refs_may_alias_p (tree ref1
, tree base1
,
1552 poly_int64 offset1
, poly_int64 max_size1
,
1554 tree ref2
, tree base2
,
1555 poly_int64 offset2
, poly_int64 max_size2
,
1558 gcc_checking_assert (DECL_P (base1
) && DECL_P (base2
));
1560 /* If both references are based on different variables, they cannot alias. */
1561 if (compare_base_decls (base1
, base2
) == 0)
1564 /* If both references are based on the same variable, they cannot alias if
1565 the accesses do not overlap. */
1566 if (!ranges_maybe_overlap_p (offset1
, max_size1
, offset2
, max_size2
))
1569 /* If there is must alias, there is no use disambiguating further. */
1570 if (known_eq (size1
, max_size1
) && known_eq (size2
, max_size2
))
1573 /* For components with variable position, the above test isn't sufficient,
1574 so we disambiguate component references manually. */
1576 && handled_component_p (ref1
) && handled_component_p (ref2
)
1577 && nonoverlapping_component_refs_since_match_p (NULL
, ref1
,
1584 /* Return true if an indirect reference based on *PTR1 constrained
1585 to [OFFSET1, OFFSET1 + MAX_SIZE1) may alias a variable based on BASE2
1586 constrained to [OFFSET2, OFFSET2 + MAX_SIZE2). *PTR1 and BASE2 have
1587 the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1
1588 in which case they are computed on-demand. REF1 and REF2
1589 if non-NULL are the complete memory reference trees. */
1592 indirect_ref_may_alias_decl_p (tree ref1 ATTRIBUTE_UNUSED
, tree base1
,
1593 poly_int64 offset1
, poly_int64 max_size1
,
1595 alias_set_type ref1_alias_set
,
1596 alias_set_type base1_alias_set
,
1597 tree ref2 ATTRIBUTE_UNUSED
, tree base2
,
1598 poly_int64 offset2
, poly_int64 max_size2
,
1600 alias_set_type ref2_alias_set
,
1601 alias_set_type base2_alias_set
, bool tbaa_p
)
1604 tree ptrtype1
, dbase2
;
1606 gcc_checking_assert ((TREE_CODE (base1
) == MEM_REF
1607 || TREE_CODE (base1
) == TARGET_MEM_REF
)
1610 ptr1
= TREE_OPERAND (base1
, 0);
1611 poly_offset_int moff
= mem_ref_offset (base1
) << LOG2_BITS_PER_UNIT
;
1613 /* If only one reference is based on a variable, they cannot alias if
1614 the pointer access is beyond the extent of the variable access.
1615 (the pointer base cannot validly point to an offset less than zero
1617 ??? IVOPTs creates bases that do not honor this restriction,
1618 so do not apply this optimization for TARGET_MEM_REFs. */
1619 if (TREE_CODE (base1
) != TARGET_MEM_REF
1620 && !ranges_maybe_overlap_p (offset1
+ moff
, -1, offset2
, max_size2
))
1622 /* They also cannot alias if the pointer may not point to the decl. */
1623 if (!ptr_deref_may_alias_decl_p (ptr1
, base2
))
1626 /* Disambiguations that rely on strict aliasing rules follow. */
1627 if (!flag_strict_aliasing
|| !tbaa_p
)
1630 /* If the alias set for a pointer access is zero all bets are off. */
1631 if (base1_alias_set
== 0 || base2_alias_set
== 0)
1634 /* When we are trying to disambiguate an access with a pointer dereference
1635 as base versus one with a decl as base we can use both the size
1636 of the decl and its dynamic type for extra disambiguation.
1637 ??? We do not know anything about the dynamic type of the decl
1638 other than that its alias-set contains base2_alias_set as a subset
1639 which does not help us here. */
1640 /* As we know nothing useful about the dynamic type of the decl just
1641 use the usual conflict check rather than a subset test.
1642 ??? We could introduce -fvery-strict-aliasing when the language
1643 does not allow decls to have a dynamic type that differs from their
1644 static type. Then we can check
1645 !alias_set_subset_of (base1_alias_set, base2_alias_set) instead. */
1646 if (base1_alias_set
!= base2_alias_set
1647 && !alias_sets_conflict_p (base1_alias_set
, base2_alias_set
))
1650 ptrtype1
= TREE_TYPE (TREE_OPERAND (base1
, 1));
1652 /* If the size of the access relevant for TBAA through the pointer
1653 is bigger than the size of the decl we can't possibly access the
1654 decl via that pointer. */
1655 if (/* ??? This in turn may run afoul when a decl of type T which is
1656 a member of union type U is accessed through a pointer to
1657 type U and sizeof T is smaller than sizeof U. */
1658 TREE_CODE (TREE_TYPE (ptrtype1
)) != UNION_TYPE
1659 && TREE_CODE (TREE_TYPE (ptrtype1
)) != QUAL_UNION_TYPE
1660 && compare_sizes (DECL_SIZE (base2
),
1661 TYPE_SIZE (TREE_TYPE (ptrtype1
))) < 0)
1667 /* If the decl is accessed via a MEM_REF, reconstruct the base
1668 we can use for TBAA and an appropriately adjusted offset. */
1670 while (handled_component_p (dbase2
))
1671 dbase2
= TREE_OPERAND (dbase2
, 0);
1672 poly_int64 doffset1
= offset1
;
1673 poly_offset_int doffset2
= offset2
;
1674 if (TREE_CODE (dbase2
) == MEM_REF
1675 || TREE_CODE (dbase2
) == TARGET_MEM_REF
)
1677 doffset2
-= mem_ref_offset (dbase2
) << LOG2_BITS_PER_UNIT
;
1678 tree ptrtype2
= TREE_TYPE (TREE_OPERAND (dbase2
, 1));
1679 /* If second reference is view-converted, give up now. */
1680 if (same_type_for_tbaa (TREE_TYPE (dbase2
), TREE_TYPE (ptrtype2
)) != 1)
1684 /* If first reference is view-converted, give up now. */
1685 if (same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (ptrtype1
)) != 1)
1688 /* If both references are through the same type, they do not alias
1689 if the accesses do not overlap. This does extra disambiguation
1690 for mixed/pointer accesses but requires strict aliasing.
1691 For MEM_REFs we require that the component-ref offset we computed
1692 is relative to the start of the type which we ensure by
1693 comparing rvalue and access type and disregarding the constant
1696 But avoid treating variable length arrays as "objects", instead assume they
1697 can overlap by an exact multiple of their element size.
1698 See gcc.dg/torture/alias-2.c. */
1699 if (((TREE_CODE (base1
) != TARGET_MEM_REF
1700 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1701 && (TREE_CODE (dbase2
) != TARGET_MEM_REF
1702 || (!TMR_INDEX (dbase2
) && !TMR_INDEX2 (dbase2
))))
1703 && same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (dbase2
)) == 1
1704 && (TREE_CODE (TREE_TYPE (base1
)) != ARRAY_TYPE
1705 || (TYPE_SIZE (TREE_TYPE (base1
))
1706 && TREE_CODE (TYPE_SIZE (TREE_TYPE (base1
))) == INTEGER_CST
)))
1708 if (!ranges_maybe_overlap_p (doffset1
, max_size1
, doffset2
, max_size2
))
1711 /* If there is must alias, there is no use disambiguating further. */
1712 || (known_eq (size1
, max_size1
) && known_eq (size2
, max_size2
)))
1714 int res
= nonoverlapping_component_refs_since_match_p (base1
, ref1
,
1717 return !nonoverlapping_component_refs_p (ref1
, ref2
);
1721 /* Do access-path based disambiguation. */
1723 && (handled_component_p (ref1
) || handled_component_p (ref2
)))
1724 return aliasing_component_refs_p (ref1
,
1725 ref1_alias_set
, base1_alias_set
,
1728 ref2_alias_set
, base2_alias_set
,
1729 offset2
, max_size2
);
1734 /* Return true if two indirect references based on *PTR1
1735 and *PTR2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and
1736 [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. *PTR1 and *PTR2 have
1737 the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1
1738 in which case they are computed on-demand. REF1 and REF2
1739 if non-NULL are the complete memory reference trees. */
1742 indirect_refs_may_alias_p (tree ref1 ATTRIBUTE_UNUSED
, tree base1
,
1743 poly_int64 offset1
, poly_int64 max_size1
,
1745 alias_set_type ref1_alias_set
,
1746 alias_set_type base1_alias_set
,
1747 tree ref2 ATTRIBUTE_UNUSED
, tree base2
,
1748 poly_int64 offset2
, poly_int64 max_size2
,
1750 alias_set_type ref2_alias_set
,
1751 alias_set_type base2_alias_set
, bool tbaa_p
)
1755 tree ptrtype1
, ptrtype2
;
1757 gcc_checking_assert ((TREE_CODE (base1
) == MEM_REF
1758 || TREE_CODE (base1
) == TARGET_MEM_REF
)
1759 && (TREE_CODE (base2
) == MEM_REF
1760 || TREE_CODE (base2
) == TARGET_MEM_REF
));
1762 ptr1
= TREE_OPERAND (base1
, 0);
1763 ptr2
= TREE_OPERAND (base2
, 0);
1765 /* If both bases are based on pointers they cannot alias if they may not
1766 point to the same memory object or if they point to the same object
1767 and the accesses do not overlap. */
1768 if ((!cfun
|| gimple_in_ssa_p (cfun
))
1769 && operand_equal_p (ptr1
, ptr2
, 0)
1770 && (((TREE_CODE (base1
) != TARGET_MEM_REF
1771 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1772 && (TREE_CODE (base2
) != TARGET_MEM_REF
1773 || (!TMR_INDEX (base2
) && !TMR_INDEX2 (base2
))))
1774 || (TREE_CODE (base1
) == TARGET_MEM_REF
1775 && TREE_CODE (base2
) == TARGET_MEM_REF
1776 && (TMR_STEP (base1
) == TMR_STEP (base2
)
1777 || (TMR_STEP (base1
) && TMR_STEP (base2
)
1778 && operand_equal_p (TMR_STEP (base1
),
1779 TMR_STEP (base2
), 0)))
1780 && (TMR_INDEX (base1
) == TMR_INDEX (base2
)
1781 || (TMR_INDEX (base1
) && TMR_INDEX (base2
)
1782 && operand_equal_p (TMR_INDEX (base1
),
1783 TMR_INDEX (base2
), 0)))
1784 && (TMR_INDEX2 (base1
) == TMR_INDEX2 (base2
)
1785 || (TMR_INDEX2 (base1
) && TMR_INDEX2 (base2
)
1786 && operand_equal_p (TMR_INDEX2 (base1
),
1787 TMR_INDEX2 (base2
), 0))))))
1789 poly_offset_int moff1
= mem_ref_offset (base1
) << LOG2_BITS_PER_UNIT
;
1790 poly_offset_int moff2
= mem_ref_offset (base2
) << LOG2_BITS_PER_UNIT
;
1791 if (!ranges_maybe_overlap_p (offset1
+ moff1
, max_size1
,
1792 offset2
+ moff2
, max_size2
))
1794 /* If there is must alias, there is no use disambiguating further. */
1795 if (known_eq (size1
, max_size1
) && known_eq (size2
, max_size2
))
1799 int res
= nonoverlapping_component_refs_since_match_p (NULL
, ref1
,
1805 if (!ptr_derefs_may_alias_p (ptr1
, ptr2
))
1808 /* Disambiguations that rely on strict aliasing rules follow. */
1809 if (!flag_strict_aliasing
|| !tbaa_p
)
1812 ptrtype1
= TREE_TYPE (TREE_OPERAND (base1
, 1));
1813 ptrtype2
= TREE_TYPE (TREE_OPERAND (base2
, 1));
1815 /* If the alias set for a pointer access is zero all bets are off. */
1816 if (base1_alias_set
== 0
1817 || base2_alias_set
== 0)
1820 /* Do type-based disambiguation. */
1821 if (base1_alias_set
!= base2_alias_set
1822 && !alias_sets_conflict_p (base1_alias_set
, base2_alias_set
))
1825 /* If either reference is view-converted, give up now. */
1826 if (same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (ptrtype1
)) != 1
1827 || same_type_for_tbaa (TREE_TYPE (base2
), TREE_TYPE (ptrtype2
)) != 1)
1830 /* If both references are through the same type, they do not alias
1831 if the accesses do not overlap. This does extra disambiguation
1832 for mixed/pointer accesses but requires strict aliasing. */
1833 if ((TREE_CODE (base1
) != TARGET_MEM_REF
1834 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1835 && (TREE_CODE (base2
) != TARGET_MEM_REF
1836 || (!TMR_INDEX (base2
) && !TMR_INDEX2 (base2
)))
1837 && same_type_for_tbaa (TREE_TYPE (ptrtype1
),
1838 TREE_TYPE (ptrtype2
)) == 1
1839 /* But avoid treating arrays as "objects", instead assume they
1840 can overlap by an exact multiple of their element size.
1841 See gcc.dg/torture/alias-2.c. */
1842 && TREE_CODE (TREE_TYPE (ptrtype1
)) != ARRAY_TYPE
)
1844 if (!ranges_maybe_overlap_p (offset1
, max_size1
, offset2
, max_size2
))
1847 || (known_eq (size1
, max_size1
) && known_eq (size2
, max_size2
)))
1849 int res
= nonoverlapping_component_refs_since_match_p (base1
, ref1
,
1852 return !nonoverlapping_component_refs_p (ref1
, ref2
);
1856 /* Do access-path based disambiguation. */
1858 && (handled_component_p (ref1
) || handled_component_p (ref2
)))
1859 return aliasing_component_refs_p (ref1
,
1860 ref1_alias_set
, base1_alias_set
,
1863 ref2_alias_set
, base2_alias_set
,
1864 offset2
, max_size2
);
1869 /* Return true, if the two memory references REF1 and REF2 may alias. */
1872 refs_may_alias_p_2 (ao_ref
*ref1
, ao_ref
*ref2
, bool tbaa_p
)
1875 poly_int64 offset1
= 0, offset2
= 0;
1876 poly_int64 max_size1
= -1, max_size2
= -1;
1877 bool var1_p
, var2_p
, ind1_p
, ind2_p
;
1879 gcc_checking_assert ((!ref1
->ref
1880 || TREE_CODE (ref1
->ref
) == SSA_NAME
1881 || DECL_P (ref1
->ref
)
1882 || TREE_CODE (ref1
->ref
) == STRING_CST
1883 || handled_component_p (ref1
->ref
)
1884 || TREE_CODE (ref1
->ref
) == MEM_REF
1885 || TREE_CODE (ref1
->ref
) == TARGET_MEM_REF
)
1887 || TREE_CODE (ref2
->ref
) == SSA_NAME
1888 || DECL_P (ref2
->ref
)
1889 || TREE_CODE (ref2
->ref
) == STRING_CST
1890 || handled_component_p (ref2
->ref
)
1891 || TREE_CODE (ref2
->ref
) == MEM_REF
1892 || TREE_CODE (ref2
->ref
) == TARGET_MEM_REF
));
1894 /* Decompose the references into their base objects and the access. */
1895 base1
= ao_ref_base (ref1
);
1896 offset1
= ref1
->offset
;
1897 max_size1
= ref1
->max_size
;
1898 base2
= ao_ref_base (ref2
);
1899 offset2
= ref2
->offset
;
1900 max_size2
= ref2
->max_size
;
1902 /* We can end up with registers or constants as bases for example from
1903 *D.1663_44 = VIEW_CONVERT_EXPR<struct DB_LSN>(__tmp$B0F64_59);
1904 which is seen as a struct copy. */
1905 if (TREE_CODE (base1
) == SSA_NAME
1906 || TREE_CODE (base1
) == CONST_DECL
1907 || TREE_CODE (base1
) == CONSTRUCTOR
1908 || TREE_CODE (base1
) == ADDR_EXPR
1909 || CONSTANT_CLASS_P (base1
)
1910 || TREE_CODE (base2
) == SSA_NAME
1911 || TREE_CODE (base2
) == CONST_DECL
1912 || TREE_CODE (base2
) == CONSTRUCTOR
1913 || TREE_CODE (base2
) == ADDR_EXPR
1914 || CONSTANT_CLASS_P (base2
))
1917 /* We can end up referring to code via function and label decls.
1918 As we likely do not properly track code aliases conservatively
1920 if (TREE_CODE (base1
) == FUNCTION_DECL
1921 || TREE_CODE (base1
) == LABEL_DECL
1922 || TREE_CODE (base2
) == FUNCTION_DECL
1923 || TREE_CODE (base2
) == LABEL_DECL
)
1926 /* Two volatile accesses always conflict. */
1927 if (ref1
->volatile_p
1928 && ref2
->volatile_p
)
1931 /* Defer to simple offset based disambiguation if we have
1932 references based on two decls. Do this before defering to
1933 TBAA to handle must-alias cases in conformance with the
1934 GCC extension of allowing type-punning through unions. */
1935 var1_p
= DECL_P (base1
);
1936 var2_p
= DECL_P (base2
);
1937 if (var1_p
&& var2_p
)
1938 return decl_refs_may_alias_p (ref1
->ref
, base1
, offset1
, max_size1
,
1940 ref2
->ref
, base2
, offset2
, max_size2
,
1943 /* Handle restrict based accesses.
1944 ??? ao_ref_base strips inner MEM_REF [&decl], recover from that
1946 tree rbase1
= base1
;
1947 tree rbase2
= base2
;
1952 while (handled_component_p (rbase1
))
1953 rbase1
= TREE_OPERAND (rbase1
, 0);
1959 while (handled_component_p (rbase2
))
1960 rbase2
= TREE_OPERAND (rbase2
, 0);
1962 if (rbase1
&& rbase2
1963 && (TREE_CODE (base1
) == MEM_REF
|| TREE_CODE (base1
) == TARGET_MEM_REF
)
1964 && (TREE_CODE (base2
) == MEM_REF
|| TREE_CODE (base2
) == TARGET_MEM_REF
)
1965 /* If the accesses are in the same restrict clique... */
1966 && MR_DEPENDENCE_CLIQUE (base1
) == MR_DEPENDENCE_CLIQUE (base2
)
1967 /* But based on different pointers they do not alias. */
1968 && MR_DEPENDENCE_BASE (base1
) != MR_DEPENDENCE_BASE (base2
))
1971 ind1_p
= (TREE_CODE (base1
) == MEM_REF
1972 || TREE_CODE (base1
) == TARGET_MEM_REF
);
1973 ind2_p
= (TREE_CODE (base2
) == MEM_REF
1974 || TREE_CODE (base2
) == TARGET_MEM_REF
);
1976 /* Canonicalize the pointer-vs-decl case. */
1977 if (ind1_p
&& var2_p
)
1979 std::swap (offset1
, offset2
);
1980 std::swap (max_size1
, max_size2
);
1981 std::swap (base1
, base2
);
1982 std::swap (ref1
, ref2
);
1989 /* First defer to TBAA if possible. */
1991 && flag_strict_aliasing
1992 && !alias_sets_conflict_p (ao_ref_alias_set (ref1
),
1993 ao_ref_alias_set (ref2
)))
1996 /* If the reference is based on a pointer that points to memory
1997 that may not be written to then the other reference cannot possibly
1999 if ((TREE_CODE (TREE_OPERAND (base2
, 0)) == SSA_NAME
2000 && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base2
, 0)))
2002 && TREE_CODE (TREE_OPERAND (base1
, 0)) == SSA_NAME
2003 && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base1
, 0))))
2006 /* Dispatch to the pointer-vs-decl or pointer-vs-pointer disambiguators. */
2007 if (var1_p
&& ind2_p
)
2008 return indirect_ref_may_alias_decl_p (ref2
->ref
, base2
,
2009 offset2
, max_size2
, ref2
->size
,
2010 ao_ref_alias_set (ref2
),
2011 ao_ref_base_alias_set (ref2
),
2013 offset1
, max_size1
, ref1
->size
,
2014 ao_ref_alias_set (ref1
),
2015 ao_ref_base_alias_set (ref1
),
2017 else if (ind1_p
&& ind2_p
)
2018 return indirect_refs_may_alias_p (ref1
->ref
, base1
,
2019 offset1
, max_size1
, ref1
->size
,
2020 ao_ref_alias_set (ref1
),
2021 ao_ref_base_alias_set (ref1
),
2023 offset2
, max_size2
, ref2
->size
,
2024 ao_ref_alias_set (ref2
),
2025 ao_ref_base_alias_set (ref2
),
2031 /* Return true, if the two memory references REF1 and REF2 may alias
2032 and update statistics. */
2035 refs_may_alias_p_1 (ao_ref
*ref1
, ao_ref
*ref2
, bool tbaa_p
)
2037 bool res
= refs_may_alias_p_2 (ref1
, ref2
, tbaa_p
);
2039 ++alias_stats
.refs_may_alias_p_may_alias
;
2041 ++alias_stats
.refs_may_alias_p_no_alias
;
2046 refs_may_alias_p (tree ref1
, ao_ref
*ref2
, bool tbaa_p
)
2049 ao_ref_init (&r1
, ref1
);
2050 return refs_may_alias_p_1 (&r1
, ref2
, tbaa_p
);
2054 refs_may_alias_p (tree ref1
, tree ref2
, bool tbaa_p
)
2057 ao_ref_init (&r1
, ref1
);
2058 ao_ref_init (&r2
, ref2
);
2059 return refs_may_alias_p_1 (&r1
, &r2
, tbaa_p
);
2062 /* Returns true if there is a anti-dependence for the STORE that
2063 executes after the LOAD. */
2066 refs_anti_dependent_p (tree load
, tree store
)
2069 ao_ref_init (&r1
, load
);
2070 ao_ref_init (&r2
, store
);
2071 return refs_may_alias_p_1 (&r1
, &r2
, false);
2074 /* Returns true if there is a output dependence for the stores
2075 STORE1 and STORE2. */
2078 refs_output_dependent_p (tree store1
, tree store2
)
2081 ao_ref_init (&r1
, store1
);
2082 ao_ref_init (&r2
, store2
);
2083 return refs_may_alias_p_1 (&r1
, &r2
, false);
2086 /* If the call CALL may use the memory reference REF return true,
2087 otherwise return false. */
2090 ref_maybe_used_by_call_p_1 (gcall
*call
, ao_ref
*ref
, bool tbaa_p
)
2094 int flags
= gimple_call_flags (call
);
2096 /* Const functions without a static chain do not implicitly use memory. */
2097 if (!gimple_call_chain (call
)
2098 && (flags
& (ECF_CONST
|ECF_NOVOPS
)))
2101 base
= ao_ref_base (ref
);
2105 /* A call that is not without side-effects might involve volatile
2106 accesses and thus conflicts with all other volatile accesses. */
2107 if (ref
->volatile_p
)
2110 /* If the reference is based on a decl that is not aliased the call
2111 cannot possibly use it. */
2113 && !may_be_aliased (base
)
2114 /* But local statics can be used through recursion. */
2115 && !is_global_var (base
))
2118 callee
= gimple_call_fndecl (call
);
2120 /* Handle those builtin functions explicitly that do not act as
2121 escape points. See tree-ssa-structalias.c:find_func_aliases
2122 for the list of builtins we might need to handle here. */
2123 if (callee
!= NULL_TREE
2124 && gimple_call_builtin_p (call
, BUILT_IN_NORMAL
))
2125 switch (DECL_FUNCTION_CODE (callee
))
2127 /* All the following functions read memory pointed to by
2128 their second argument. strcat/strncat additionally
2129 reads memory pointed to by the first argument. */
2130 case BUILT_IN_STRCAT
:
2131 case BUILT_IN_STRNCAT
:
2134 ao_ref_init_from_ptr_and_size (&dref
,
2135 gimple_call_arg (call
, 0),
2137 if (refs_may_alias_p_1 (&dref
, ref
, false))
2141 case BUILT_IN_STRCPY
:
2142 case BUILT_IN_STRNCPY
:
2143 case BUILT_IN_MEMCPY
:
2144 case BUILT_IN_MEMMOVE
:
2145 case BUILT_IN_MEMPCPY
:
2146 case BUILT_IN_STPCPY
:
2147 case BUILT_IN_STPNCPY
:
2148 case BUILT_IN_TM_MEMCPY
:
2149 case BUILT_IN_TM_MEMMOVE
:
2152 tree size
= NULL_TREE
;
2153 if (gimple_call_num_args (call
) == 3)
2154 size
= gimple_call_arg (call
, 2);
2155 ao_ref_init_from_ptr_and_size (&dref
,
2156 gimple_call_arg (call
, 1),
2158 return refs_may_alias_p_1 (&dref
, ref
, false);
2160 case BUILT_IN_STRCAT_CHK
:
2161 case BUILT_IN_STRNCAT_CHK
:
2164 ao_ref_init_from_ptr_and_size (&dref
,
2165 gimple_call_arg (call
, 0),
2167 if (refs_may_alias_p_1 (&dref
, ref
, false))
2171 case BUILT_IN_STRCPY_CHK
:
2172 case BUILT_IN_STRNCPY_CHK
:
2173 case BUILT_IN_MEMCPY_CHK
:
2174 case BUILT_IN_MEMMOVE_CHK
:
2175 case BUILT_IN_MEMPCPY_CHK
:
2176 case BUILT_IN_STPCPY_CHK
:
2177 case BUILT_IN_STPNCPY_CHK
:
2180 tree size
= NULL_TREE
;
2181 if (gimple_call_num_args (call
) == 4)
2182 size
= gimple_call_arg (call
, 2);
2183 ao_ref_init_from_ptr_and_size (&dref
,
2184 gimple_call_arg (call
, 1),
2186 return refs_may_alias_p_1 (&dref
, ref
, false);
2188 case BUILT_IN_BCOPY
:
2191 tree size
= gimple_call_arg (call
, 2);
2192 ao_ref_init_from_ptr_and_size (&dref
,
2193 gimple_call_arg (call
, 0),
2195 return refs_may_alias_p_1 (&dref
, ref
, false);
2198 /* The following functions read memory pointed to by their
2200 CASE_BUILT_IN_TM_LOAD (1):
2201 CASE_BUILT_IN_TM_LOAD (2):
2202 CASE_BUILT_IN_TM_LOAD (4):
2203 CASE_BUILT_IN_TM_LOAD (8):
2204 CASE_BUILT_IN_TM_LOAD (FLOAT
):
2205 CASE_BUILT_IN_TM_LOAD (DOUBLE
):
2206 CASE_BUILT_IN_TM_LOAD (LDOUBLE
):
2207 CASE_BUILT_IN_TM_LOAD (M64
):
2208 CASE_BUILT_IN_TM_LOAD (M128
):
2209 CASE_BUILT_IN_TM_LOAD (M256
):
2210 case BUILT_IN_TM_LOG
:
2211 case BUILT_IN_TM_LOG_1
:
2212 case BUILT_IN_TM_LOG_2
:
2213 case BUILT_IN_TM_LOG_4
:
2214 case BUILT_IN_TM_LOG_8
:
2215 case BUILT_IN_TM_LOG_FLOAT
:
2216 case BUILT_IN_TM_LOG_DOUBLE
:
2217 case BUILT_IN_TM_LOG_LDOUBLE
:
2218 case BUILT_IN_TM_LOG_M64
:
2219 case BUILT_IN_TM_LOG_M128
:
2220 case BUILT_IN_TM_LOG_M256
:
2221 return ptr_deref_may_alias_ref_p_1 (gimple_call_arg (call
, 0), ref
);
2223 /* These read memory pointed to by the first argument. */
2224 case BUILT_IN_STRDUP
:
2225 case BUILT_IN_STRNDUP
:
2226 case BUILT_IN_REALLOC
:
2229 tree size
= NULL_TREE
;
2230 if (gimple_call_num_args (call
) == 2)
2231 size
= gimple_call_arg (call
, 1);
2232 ao_ref_init_from_ptr_and_size (&dref
,
2233 gimple_call_arg (call
, 0),
2235 return refs_may_alias_p_1 (&dref
, ref
, false);
2237 /* These read memory pointed to by the first argument. */
2238 case BUILT_IN_INDEX
:
2239 case BUILT_IN_STRCHR
:
2240 case BUILT_IN_STRRCHR
:
2243 ao_ref_init_from_ptr_and_size (&dref
,
2244 gimple_call_arg (call
, 0),
2246 return refs_may_alias_p_1 (&dref
, ref
, false);
2248 /* These read memory pointed to by the first argument with size
2249 in the third argument. */
2250 case BUILT_IN_MEMCHR
:
2253 ao_ref_init_from_ptr_and_size (&dref
,
2254 gimple_call_arg (call
, 0),
2255 gimple_call_arg (call
, 2));
2256 return refs_may_alias_p_1 (&dref
, ref
, false);
2258 /* These read memory pointed to by the first and second arguments. */
2259 case BUILT_IN_STRSTR
:
2260 case BUILT_IN_STRPBRK
:
2263 ao_ref_init_from_ptr_and_size (&dref
,
2264 gimple_call_arg (call
, 0),
2266 if (refs_may_alias_p_1 (&dref
, ref
, false))
2268 ao_ref_init_from_ptr_and_size (&dref
,
2269 gimple_call_arg (call
, 1),
2271 return refs_may_alias_p_1 (&dref
, ref
, false);
2274 /* The following builtins do not read from memory. */
2276 case BUILT_IN_MALLOC
:
2277 case BUILT_IN_POSIX_MEMALIGN
:
2278 case BUILT_IN_ALIGNED_ALLOC
:
2279 case BUILT_IN_CALLOC
:
2280 CASE_BUILT_IN_ALLOCA
:
2281 case BUILT_IN_STACK_SAVE
:
2282 case BUILT_IN_STACK_RESTORE
:
2283 case BUILT_IN_MEMSET
:
2284 case BUILT_IN_TM_MEMSET
:
2285 case BUILT_IN_MEMSET_CHK
:
2286 case BUILT_IN_FREXP
:
2287 case BUILT_IN_FREXPF
:
2288 case BUILT_IN_FREXPL
:
2289 case BUILT_IN_GAMMA_R
:
2290 case BUILT_IN_GAMMAF_R
:
2291 case BUILT_IN_GAMMAL_R
:
2292 case BUILT_IN_LGAMMA_R
:
2293 case BUILT_IN_LGAMMAF_R
:
2294 case BUILT_IN_LGAMMAL_R
:
2296 case BUILT_IN_MODFF
:
2297 case BUILT_IN_MODFL
:
2298 case BUILT_IN_REMQUO
:
2299 case BUILT_IN_REMQUOF
:
2300 case BUILT_IN_REMQUOL
:
2301 case BUILT_IN_SINCOS
:
2302 case BUILT_IN_SINCOSF
:
2303 case BUILT_IN_SINCOSL
:
2304 case BUILT_IN_ASSUME_ALIGNED
:
2305 case BUILT_IN_VA_END
:
2307 /* __sync_* builtins and some OpenMP builtins act as threading
2309 #undef DEF_SYNC_BUILTIN
2310 #define DEF_SYNC_BUILTIN(ENUM, NAME, TYPE, ATTRS) case ENUM:
2311 #include "sync-builtins.def"
2312 #undef DEF_SYNC_BUILTIN
2313 case BUILT_IN_GOMP_ATOMIC_START
:
2314 case BUILT_IN_GOMP_ATOMIC_END
:
2315 case BUILT_IN_GOMP_BARRIER
:
2316 case BUILT_IN_GOMP_BARRIER_CANCEL
:
2317 case BUILT_IN_GOMP_TASKWAIT
:
2318 case BUILT_IN_GOMP_TASKGROUP_END
:
2319 case BUILT_IN_GOMP_CRITICAL_START
:
2320 case BUILT_IN_GOMP_CRITICAL_END
:
2321 case BUILT_IN_GOMP_CRITICAL_NAME_START
:
2322 case BUILT_IN_GOMP_CRITICAL_NAME_END
:
2323 case BUILT_IN_GOMP_LOOP_END
:
2324 case BUILT_IN_GOMP_LOOP_END_CANCEL
:
2325 case BUILT_IN_GOMP_ORDERED_START
:
2326 case BUILT_IN_GOMP_ORDERED_END
:
2327 case BUILT_IN_GOMP_SECTIONS_END
:
2328 case BUILT_IN_GOMP_SECTIONS_END_CANCEL
:
2329 case BUILT_IN_GOMP_SINGLE_COPY_START
:
2330 case BUILT_IN_GOMP_SINGLE_COPY_END
:
2334 /* Fallthru to general call handling. */;
2337 /* Check if base is a global static variable that is not read
2339 if (callee
!= NULL_TREE
&& VAR_P (base
) && TREE_STATIC (base
))
2341 struct cgraph_node
*node
= cgraph_node::get (callee
);
2344 /* FIXME: Callee can be an OMP builtin that does not have a call graph
2345 node yet. We should enforce that there are nodes for all decls in the
2346 IL and remove this check instead. */
2348 && (not_read
= ipa_reference_get_not_read_global (node
))
2349 && bitmap_bit_p (not_read
, ipa_reference_var_uid (base
)))
2353 /* Check if the base variable is call-used. */
2356 if (pt_solution_includes (gimple_call_use_set (call
), base
))
2359 else if ((TREE_CODE (base
) == MEM_REF
2360 || TREE_CODE (base
) == TARGET_MEM_REF
)
2361 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
)
2363 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (TREE_OPERAND (base
, 0));
2367 if (pt_solutions_intersect (gimple_call_use_set (call
), &pi
->pt
))
2373 /* Inspect call arguments for passed-by-value aliases. */
2375 for (i
= 0; i
< gimple_call_num_args (call
); ++i
)
2377 tree op
= gimple_call_arg (call
, i
);
2378 int flags
= gimple_call_arg_flags (call
, i
);
2380 if (flags
& EAF_UNUSED
)
2383 if (TREE_CODE (op
) == WITH_SIZE_EXPR
)
2384 op
= TREE_OPERAND (op
, 0);
2386 if (TREE_CODE (op
) != SSA_NAME
2387 && !is_gimple_min_invariant (op
))
2390 ao_ref_init (&r
, op
);
2391 if (refs_may_alias_p_1 (&r
, ref
, tbaa_p
))
2400 ref_maybe_used_by_call_p (gcall
*call
, ao_ref
*ref
, bool tbaa_p
)
2403 res
= ref_maybe_used_by_call_p_1 (call
, ref
, tbaa_p
);
2405 ++alias_stats
.ref_maybe_used_by_call_p_may_alias
;
2407 ++alias_stats
.ref_maybe_used_by_call_p_no_alias
;
2412 /* If the statement STMT may use the memory reference REF return
2413 true, otherwise return false. */
2416 ref_maybe_used_by_stmt_p (gimple
*stmt
, ao_ref
*ref
, bool tbaa_p
)
2418 if (is_gimple_assign (stmt
))
2422 /* All memory assign statements are single. */
2423 if (!gimple_assign_single_p (stmt
))
2426 rhs
= gimple_assign_rhs1 (stmt
);
2427 if (is_gimple_reg (rhs
)
2428 || is_gimple_min_invariant (rhs
)
2429 || gimple_assign_rhs_code (stmt
) == CONSTRUCTOR
)
2432 return refs_may_alias_p (rhs
, ref
, tbaa_p
);
2434 else if (is_gimple_call (stmt
))
2435 return ref_maybe_used_by_call_p (as_a
<gcall
*> (stmt
), ref
, tbaa_p
);
2436 else if (greturn
*return_stmt
= dyn_cast
<greturn
*> (stmt
))
2438 tree retval
= gimple_return_retval (return_stmt
);
2440 && TREE_CODE (retval
) != SSA_NAME
2441 && !is_gimple_min_invariant (retval
)
2442 && refs_may_alias_p (retval
, ref
, tbaa_p
))
2444 /* If ref escapes the function then the return acts as a use. */
2445 tree base
= ao_ref_base (ref
);
2448 else if (DECL_P (base
))
2449 return is_global_var (base
);
2450 else if (TREE_CODE (base
) == MEM_REF
2451 || TREE_CODE (base
) == TARGET_MEM_REF
)
2452 return ptr_deref_may_alias_global_p (TREE_OPERAND (base
, 0));
2460 ref_maybe_used_by_stmt_p (gimple
*stmt
, tree ref
, bool tbaa_p
)
2463 ao_ref_init (&r
, ref
);
2464 return ref_maybe_used_by_stmt_p (stmt
, &r
, tbaa_p
);
2467 /* If the call in statement CALL may clobber the memory reference REF
2468 return true, otherwise return false. */
2471 call_may_clobber_ref_p_1 (gcall
*call
, ao_ref
*ref
)
2476 /* If the call is pure or const it cannot clobber anything. */
2477 if (gimple_call_flags (call
)
2478 & (ECF_PURE
|ECF_CONST
|ECF_LOOPING_CONST_OR_PURE
|ECF_NOVOPS
))
2480 if (gimple_call_internal_p (call
))
2481 switch (gimple_call_internal_fn (call
))
2483 /* Treat these internal calls like ECF_PURE for aliasing,
2484 they don't write to any memory the program should care about.
2485 They have important other side-effects, and read memory,
2486 so can't be ECF_NOVOPS. */
2487 case IFN_UBSAN_NULL
:
2488 case IFN_UBSAN_BOUNDS
:
2489 case IFN_UBSAN_VPTR
:
2490 case IFN_UBSAN_OBJECT_SIZE
:
2492 case IFN_ASAN_CHECK
:
2498 base
= ao_ref_base (ref
);
2502 if (TREE_CODE (base
) == SSA_NAME
2503 || CONSTANT_CLASS_P (base
))
2506 /* A call that is not without side-effects might involve volatile
2507 accesses and thus conflicts with all other volatile accesses. */
2508 if (ref
->volatile_p
)
2511 /* If the reference is based on a decl that is not aliased the call
2512 cannot possibly clobber it. */
2514 && !may_be_aliased (base
)
2515 /* But local non-readonly statics can be modified through recursion
2516 or the call may implement a threading barrier which we must
2517 treat as may-def. */
2518 && (TREE_READONLY (base
)
2519 || !is_global_var (base
)))
2522 /* If the reference is based on a pointer that points to memory
2523 that may not be written to then the call cannot possibly clobber it. */
2524 if ((TREE_CODE (base
) == MEM_REF
2525 || TREE_CODE (base
) == TARGET_MEM_REF
)
2526 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
2527 && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base
, 0)))
2530 callee
= gimple_call_fndecl (call
);
2532 /* Handle those builtin functions explicitly that do not act as
2533 escape points. See tree-ssa-structalias.c:find_func_aliases
2534 for the list of builtins we might need to handle here. */
2535 if (callee
!= NULL_TREE
2536 && gimple_call_builtin_p (call
, BUILT_IN_NORMAL
))
2537 switch (DECL_FUNCTION_CODE (callee
))
2539 /* All the following functions clobber memory pointed to by
2540 their first argument. */
2541 case BUILT_IN_STRCPY
:
2542 case BUILT_IN_STRNCPY
:
2543 case BUILT_IN_MEMCPY
:
2544 case BUILT_IN_MEMMOVE
:
2545 case BUILT_IN_MEMPCPY
:
2546 case BUILT_IN_STPCPY
:
2547 case BUILT_IN_STPNCPY
:
2548 case BUILT_IN_STRCAT
:
2549 case BUILT_IN_STRNCAT
:
2550 case BUILT_IN_MEMSET
:
2551 case BUILT_IN_TM_MEMSET
:
2552 CASE_BUILT_IN_TM_STORE (1):
2553 CASE_BUILT_IN_TM_STORE (2):
2554 CASE_BUILT_IN_TM_STORE (4):
2555 CASE_BUILT_IN_TM_STORE (8):
2556 CASE_BUILT_IN_TM_STORE (FLOAT
):
2557 CASE_BUILT_IN_TM_STORE (DOUBLE
):
2558 CASE_BUILT_IN_TM_STORE (LDOUBLE
):
2559 CASE_BUILT_IN_TM_STORE (M64
):
2560 CASE_BUILT_IN_TM_STORE (M128
):
2561 CASE_BUILT_IN_TM_STORE (M256
):
2562 case BUILT_IN_TM_MEMCPY
:
2563 case BUILT_IN_TM_MEMMOVE
:
2566 tree size
= NULL_TREE
;
2567 /* Don't pass in size for strncat, as the maximum size
2568 is strlen (dest) + n + 1 instead of n, resp.
2569 n + 1 at dest + strlen (dest), but strlen (dest) isn't
2571 if (gimple_call_num_args (call
) == 3
2572 && DECL_FUNCTION_CODE (callee
) != BUILT_IN_STRNCAT
)
2573 size
= gimple_call_arg (call
, 2);
2574 ao_ref_init_from_ptr_and_size (&dref
,
2575 gimple_call_arg (call
, 0),
2577 return refs_may_alias_p_1 (&dref
, ref
, false);
2579 case BUILT_IN_STRCPY_CHK
:
2580 case BUILT_IN_STRNCPY_CHK
:
2581 case BUILT_IN_MEMCPY_CHK
:
2582 case BUILT_IN_MEMMOVE_CHK
:
2583 case BUILT_IN_MEMPCPY_CHK
:
2584 case BUILT_IN_STPCPY_CHK
:
2585 case BUILT_IN_STPNCPY_CHK
:
2586 case BUILT_IN_STRCAT_CHK
:
2587 case BUILT_IN_STRNCAT_CHK
:
2588 case BUILT_IN_MEMSET_CHK
:
2591 tree size
= NULL_TREE
;
2592 /* Don't pass in size for __strncat_chk, as the maximum size
2593 is strlen (dest) + n + 1 instead of n, resp.
2594 n + 1 at dest + strlen (dest), but strlen (dest) isn't
2596 if (gimple_call_num_args (call
) == 4
2597 && DECL_FUNCTION_CODE (callee
) != BUILT_IN_STRNCAT_CHK
)
2598 size
= gimple_call_arg (call
, 2);
2599 ao_ref_init_from_ptr_and_size (&dref
,
2600 gimple_call_arg (call
, 0),
2602 return refs_may_alias_p_1 (&dref
, ref
, false);
2604 case BUILT_IN_BCOPY
:
2607 tree size
= gimple_call_arg (call
, 2);
2608 ao_ref_init_from_ptr_and_size (&dref
,
2609 gimple_call_arg (call
, 1),
2611 return refs_may_alias_p_1 (&dref
, ref
, false);
2613 /* Allocating memory does not have any side-effects apart from
2614 being the definition point for the pointer. */
2615 case BUILT_IN_MALLOC
:
2616 case BUILT_IN_ALIGNED_ALLOC
:
2617 case BUILT_IN_CALLOC
:
2618 case BUILT_IN_STRDUP
:
2619 case BUILT_IN_STRNDUP
:
2620 /* Unix98 specifies that errno is set on allocation failure. */
2622 && targetm
.ref_may_alias_errno (ref
))
2625 case BUILT_IN_STACK_SAVE
:
2626 CASE_BUILT_IN_ALLOCA
:
2627 case BUILT_IN_ASSUME_ALIGNED
:
2629 /* But posix_memalign stores a pointer into the memory pointed to
2630 by its first argument. */
2631 case BUILT_IN_POSIX_MEMALIGN
:
2633 tree ptrptr
= gimple_call_arg (call
, 0);
2635 ao_ref_init_from_ptr_and_size (&dref
, ptrptr
,
2636 TYPE_SIZE_UNIT (ptr_type_node
));
2637 return (refs_may_alias_p_1 (&dref
, ref
, false)
2639 && targetm
.ref_may_alias_errno (ref
)));
2641 /* Freeing memory kills the pointed-to memory. More importantly
2642 the call has to serve as a barrier for moving loads and stores
2645 case BUILT_IN_VA_END
:
2647 tree ptr
= gimple_call_arg (call
, 0);
2648 return ptr_deref_may_alias_ref_p_1 (ptr
, ref
);
2650 /* Realloc serves both as allocation point and deallocation point. */
2651 case BUILT_IN_REALLOC
:
2653 tree ptr
= gimple_call_arg (call
, 0);
2654 /* Unix98 specifies that errno is set on allocation failure. */
2655 return ((flag_errno_math
2656 && targetm
.ref_may_alias_errno (ref
))
2657 || ptr_deref_may_alias_ref_p_1 (ptr
, ref
));
2659 case BUILT_IN_GAMMA_R
:
2660 case BUILT_IN_GAMMAF_R
:
2661 case BUILT_IN_GAMMAL_R
:
2662 case BUILT_IN_LGAMMA_R
:
2663 case BUILT_IN_LGAMMAF_R
:
2664 case BUILT_IN_LGAMMAL_R
:
2666 tree out
= gimple_call_arg (call
, 1);
2667 if (ptr_deref_may_alias_ref_p_1 (out
, ref
))
2669 if (flag_errno_math
)
2673 case BUILT_IN_FREXP
:
2674 case BUILT_IN_FREXPF
:
2675 case BUILT_IN_FREXPL
:
2677 case BUILT_IN_MODFF
:
2678 case BUILT_IN_MODFL
:
2680 tree out
= gimple_call_arg (call
, 1);
2681 return ptr_deref_may_alias_ref_p_1 (out
, ref
);
2683 case BUILT_IN_REMQUO
:
2684 case BUILT_IN_REMQUOF
:
2685 case BUILT_IN_REMQUOL
:
2687 tree out
= gimple_call_arg (call
, 2);
2688 if (ptr_deref_may_alias_ref_p_1 (out
, ref
))
2690 if (flag_errno_math
)
2694 case BUILT_IN_SINCOS
:
2695 case BUILT_IN_SINCOSF
:
2696 case BUILT_IN_SINCOSL
:
2698 tree sin
= gimple_call_arg (call
, 1);
2699 tree cos
= gimple_call_arg (call
, 2);
2700 return (ptr_deref_may_alias_ref_p_1 (sin
, ref
)
2701 || ptr_deref_may_alias_ref_p_1 (cos
, ref
));
2703 /* __sync_* builtins and some OpenMP builtins act as threading
2705 #undef DEF_SYNC_BUILTIN
2706 #define DEF_SYNC_BUILTIN(ENUM, NAME, TYPE, ATTRS) case ENUM:
2707 #include "sync-builtins.def"
2708 #undef DEF_SYNC_BUILTIN
2709 case BUILT_IN_GOMP_ATOMIC_START
:
2710 case BUILT_IN_GOMP_ATOMIC_END
:
2711 case BUILT_IN_GOMP_BARRIER
:
2712 case BUILT_IN_GOMP_BARRIER_CANCEL
:
2713 case BUILT_IN_GOMP_TASKWAIT
:
2714 case BUILT_IN_GOMP_TASKGROUP_END
:
2715 case BUILT_IN_GOMP_CRITICAL_START
:
2716 case BUILT_IN_GOMP_CRITICAL_END
:
2717 case BUILT_IN_GOMP_CRITICAL_NAME_START
:
2718 case BUILT_IN_GOMP_CRITICAL_NAME_END
:
2719 case BUILT_IN_GOMP_LOOP_END
:
2720 case BUILT_IN_GOMP_LOOP_END_CANCEL
:
2721 case BUILT_IN_GOMP_ORDERED_START
:
2722 case BUILT_IN_GOMP_ORDERED_END
:
2723 case BUILT_IN_GOMP_SECTIONS_END
:
2724 case BUILT_IN_GOMP_SECTIONS_END_CANCEL
:
2725 case BUILT_IN_GOMP_SINGLE_COPY_START
:
2726 case BUILT_IN_GOMP_SINGLE_COPY_END
:
2729 /* Fallthru to general call handling. */;
2732 /* Check if base is a global static variable that is not written
2734 if (callee
!= NULL_TREE
&& VAR_P (base
) && TREE_STATIC (base
))
2736 struct cgraph_node
*node
= cgraph_node::get (callee
);
2740 && (not_written
= ipa_reference_get_not_written_global (node
))
2741 && bitmap_bit_p (not_written
, ipa_reference_var_uid (base
)))
2745 /* Check if the base variable is call-clobbered. */
2747 return pt_solution_includes (gimple_call_clobber_set (call
), base
);
2748 else if ((TREE_CODE (base
) == MEM_REF
2749 || TREE_CODE (base
) == TARGET_MEM_REF
)
2750 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
)
2752 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (TREE_OPERAND (base
, 0));
2756 return pt_solutions_intersect (gimple_call_clobber_set (call
), &pi
->pt
);
2762 /* If the call in statement CALL may clobber the memory reference REF
2763 return true, otherwise return false. */
2766 call_may_clobber_ref_p (gcall
*call
, tree ref
)
2770 ao_ref_init (&r
, ref
);
2771 res
= call_may_clobber_ref_p_1 (call
, &r
);
2773 ++alias_stats
.call_may_clobber_ref_p_may_alias
;
2775 ++alias_stats
.call_may_clobber_ref_p_no_alias
;
2780 /* If the statement STMT may clobber the memory reference REF return true,
2781 otherwise return false. */
2784 stmt_may_clobber_ref_p_1 (gimple
*stmt
, ao_ref
*ref
, bool tbaa_p
)
2786 if (is_gimple_call (stmt
))
2788 tree lhs
= gimple_call_lhs (stmt
);
2790 && TREE_CODE (lhs
) != SSA_NAME
)
2793 ao_ref_init (&r
, lhs
);
2794 if (refs_may_alias_p_1 (ref
, &r
, tbaa_p
))
2798 return call_may_clobber_ref_p_1 (as_a
<gcall
*> (stmt
), ref
);
2800 else if (gimple_assign_single_p (stmt
))
2802 tree lhs
= gimple_assign_lhs (stmt
);
2803 if (TREE_CODE (lhs
) != SSA_NAME
)
2806 ao_ref_init (&r
, lhs
);
2807 return refs_may_alias_p_1 (ref
, &r
, tbaa_p
);
2810 else if (gimple_code (stmt
) == GIMPLE_ASM
)
2817 stmt_may_clobber_ref_p (gimple
*stmt
, tree ref
, bool tbaa_p
)
2820 ao_ref_init (&r
, ref
);
2821 return stmt_may_clobber_ref_p_1 (stmt
, &r
, tbaa_p
);
2824 /* Return true if store1 and store2 described by corresponding tuples
2825 <BASE, OFFSET, SIZE, MAX_SIZE> have the same size and store to the same
2829 same_addr_size_stores_p (tree base1
, poly_int64 offset1
, poly_int64 size1
,
2830 poly_int64 max_size1
,
2831 tree base2
, poly_int64 offset2
, poly_int64 size2
,
2832 poly_int64 max_size2
)
2834 /* Offsets need to be 0. */
2835 if (maybe_ne (offset1
, 0)
2836 || maybe_ne (offset2
, 0))
2839 bool base1_obj_p
= SSA_VAR_P (base1
);
2840 bool base2_obj_p
= SSA_VAR_P (base2
);
2842 /* We need one object. */
2843 if (base1_obj_p
== base2_obj_p
)
2845 tree obj
= base1_obj_p
? base1
: base2
;
2847 /* And we need one MEM_REF. */
2848 bool base1_memref_p
= TREE_CODE (base1
) == MEM_REF
;
2849 bool base2_memref_p
= TREE_CODE (base2
) == MEM_REF
;
2850 if (base1_memref_p
== base2_memref_p
)
2852 tree memref
= base1_memref_p
? base1
: base2
;
2854 /* Sizes need to be valid. */
2855 if (!known_size_p (max_size1
)
2856 || !known_size_p (max_size2
)
2857 || !known_size_p (size1
)
2858 || !known_size_p (size2
))
2861 /* Max_size needs to match size. */
2862 if (maybe_ne (max_size1
, size1
)
2863 || maybe_ne (max_size2
, size2
))
2866 /* Sizes need to match. */
2867 if (maybe_ne (size1
, size2
))
2871 /* Check that memref is a store to pointer with singleton points-to info. */
2872 if (!integer_zerop (TREE_OPERAND (memref
, 1)))
2874 tree ptr
= TREE_OPERAND (memref
, 0);
2875 if (TREE_CODE (ptr
) != SSA_NAME
)
2877 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (ptr
);
2878 unsigned int pt_uid
;
2880 || !pt_solution_singleton_or_null_p (&pi
->pt
, &pt_uid
))
2883 /* Be conservative with non-call exceptions when the address might
2885 if (cfun
->can_throw_non_call_exceptions
&& pi
->pt
.null
)
2888 /* Check that ptr points relative to obj. */
2889 unsigned int obj_uid
= DECL_PT_UID (obj
);
2890 if (obj_uid
!= pt_uid
)
2893 /* Check that the object size is the same as the store size. That ensures us
2894 that ptr points to the start of obj. */
2895 return (DECL_SIZE (obj
)
2896 && poly_int_tree_p (DECL_SIZE (obj
))
2897 && known_eq (wi::to_poly_offset (DECL_SIZE (obj
)), size1
));
2900 /* If STMT kills the memory reference REF return true, otherwise
2904 stmt_kills_ref_p (gimple
*stmt
, ao_ref
*ref
)
2906 if (!ao_ref_base (ref
))
2909 if (gimple_has_lhs (stmt
)
2910 && TREE_CODE (gimple_get_lhs (stmt
)) != SSA_NAME
2911 /* The assignment is not necessarily carried out if it can throw
2912 and we can catch it in the current function where we could inspect
2914 ??? We only need to care about the RHS throwing. For aggregate
2915 assignments or similar calls and non-call exceptions the LHS
2916 might throw as well. */
2917 && !stmt_can_throw_internal (cfun
, stmt
))
2919 tree lhs
= gimple_get_lhs (stmt
);
2920 /* If LHS is literally a base of the access we are done. */
2923 tree base
= ref
->ref
;
2924 tree innermost_dropped_array_ref
= NULL_TREE
;
2925 if (handled_component_p (base
))
2927 tree saved_lhs0
= NULL_TREE
;
2928 if (handled_component_p (lhs
))
2930 saved_lhs0
= TREE_OPERAND (lhs
, 0);
2931 TREE_OPERAND (lhs
, 0) = integer_zero_node
;
2935 /* Just compare the outermost handled component, if
2936 they are equal we have found a possible common
2938 tree saved_base0
= TREE_OPERAND (base
, 0);
2939 TREE_OPERAND (base
, 0) = integer_zero_node
;
2940 bool res
= operand_equal_p (lhs
, base
, 0);
2941 TREE_OPERAND (base
, 0) = saved_base0
;
2944 /* Remember if we drop an array-ref that we need to
2945 double-check not being at struct end. */
2946 if (TREE_CODE (base
) == ARRAY_REF
2947 || TREE_CODE (base
) == ARRAY_RANGE_REF
)
2948 innermost_dropped_array_ref
= base
;
2949 /* Otherwise drop handled components of the access. */
2952 while (handled_component_p (base
));
2954 TREE_OPERAND (lhs
, 0) = saved_lhs0
;
2956 /* Finally check if the lhs has the same address and size as the
2957 base candidate of the access. Watch out if we have dropped
2958 an array-ref that was at struct end, this means ref->ref may
2959 be outside of the TYPE_SIZE of its base. */
2960 if ((! innermost_dropped_array_ref
2961 || ! array_at_struct_end_p (innermost_dropped_array_ref
))
2963 || (((TYPE_SIZE (TREE_TYPE (lhs
))
2964 == TYPE_SIZE (TREE_TYPE (base
)))
2965 || (TYPE_SIZE (TREE_TYPE (lhs
))
2966 && TYPE_SIZE (TREE_TYPE (base
))
2967 && operand_equal_p (TYPE_SIZE (TREE_TYPE (lhs
)),
2968 TYPE_SIZE (TREE_TYPE (base
)),
2970 && operand_equal_p (lhs
, base
,
2972 | OEP_MATCH_SIDE_EFFECTS
))))
2976 /* Now look for non-literal equal bases with the restriction of
2977 handling constant offset and size. */
2978 /* For a must-alias check we need to be able to constrain
2979 the access properly. */
2980 if (!ref
->max_size_known_p ())
2982 poly_int64 size
, offset
, max_size
, ref_offset
= ref
->offset
;
2984 tree base
= get_ref_base_and_extent (lhs
, &offset
, &size
, &max_size
,
2986 /* We can get MEM[symbol: sZ, index: D.8862_1] here,
2987 so base == ref->base does not always hold. */
2988 if (base
!= ref
->base
)
2990 /* Try using points-to info. */
2991 if (same_addr_size_stores_p (base
, offset
, size
, max_size
, ref
->base
,
2992 ref
->offset
, ref
->size
, ref
->max_size
))
2995 /* If both base and ref->base are MEM_REFs, only compare the
2996 first operand, and if the second operand isn't equal constant,
2997 try to add the offsets into offset and ref_offset. */
2998 if (TREE_CODE (base
) == MEM_REF
&& TREE_CODE (ref
->base
) == MEM_REF
2999 && TREE_OPERAND (base
, 0) == TREE_OPERAND (ref
->base
, 0))
3001 if (!tree_int_cst_equal (TREE_OPERAND (base
, 1),
3002 TREE_OPERAND (ref
->base
, 1)))
3004 poly_offset_int off1
= mem_ref_offset (base
);
3005 off1
<<= LOG2_BITS_PER_UNIT
;
3007 poly_offset_int off2
= mem_ref_offset (ref
->base
);
3008 off2
<<= LOG2_BITS_PER_UNIT
;
3010 if (!off1
.to_shwi (&offset
) || !off2
.to_shwi (&ref_offset
))
3017 /* For a must-alias check we need to be able to constrain
3018 the access properly. */
3019 if (known_eq (size
, max_size
)
3020 && known_subrange_p (ref_offset
, ref
->max_size
, offset
, size
))
3024 if (is_gimple_call (stmt
))
3026 tree callee
= gimple_call_fndecl (stmt
);
3027 if (callee
!= NULL_TREE
3028 && gimple_call_builtin_p (stmt
, BUILT_IN_NORMAL
))
3029 switch (DECL_FUNCTION_CODE (callee
))
3033 tree ptr
= gimple_call_arg (stmt
, 0);
3034 tree base
= ao_ref_base (ref
);
3035 if (base
&& TREE_CODE (base
) == MEM_REF
3036 && TREE_OPERAND (base
, 0) == ptr
)
3041 case BUILT_IN_MEMCPY
:
3042 case BUILT_IN_MEMPCPY
:
3043 case BUILT_IN_MEMMOVE
:
3044 case BUILT_IN_MEMSET
:
3045 case BUILT_IN_MEMCPY_CHK
:
3046 case BUILT_IN_MEMPCPY_CHK
:
3047 case BUILT_IN_MEMMOVE_CHK
:
3048 case BUILT_IN_MEMSET_CHK
:
3049 case BUILT_IN_STRNCPY
:
3050 case BUILT_IN_STPNCPY
:
3051 case BUILT_IN_CALLOC
:
3053 /* For a must-alias check we need to be able to constrain
3054 the access properly. */
3055 if (!ref
->max_size_known_p ())
3060 /* In execution order a calloc call will never kill
3061 anything. However, DSE will (ab)use this interface
3062 to ask if a calloc call writes the same memory locations
3063 as a later assignment, memset, etc. So handle calloc
3064 in the expected way. */
3065 if (DECL_FUNCTION_CODE (callee
) == BUILT_IN_CALLOC
)
3067 tree arg0
= gimple_call_arg (stmt
, 0);
3068 tree arg1
= gimple_call_arg (stmt
, 1);
3069 if (TREE_CODE (arg0
) != INTEGER_CST
3070 || TREE_CODE (arg1
) != INTEGER_CST
)
3073 dest
= gimple_call_lhs (stmt
);
3074 len
= fold_build2 (MULT_EXPR
, TREE_TYPE (arg0
), arg0
, arg1
);
3078 dest
= gimple_call_arg (stmt
, 0);
3079 len
= gimple_call_arg (stmt
, 2);
3081 if (!poly_int_tree_p (len
))
3083 tree rbase
= ref
->base
;
3084 poly_offset_int roffset
= ref
->offset
;
3086 ao_ref_init_from_ptr_and_size (&dref
, dest
, len
);
3087 tree base
= ao_ref_base (&dref
);
3088 poly_offset_int offset
= dref
.offset
;
3089 if (!base
|| !known_size_p (dref
.size
))
3091 if (TREE_CODE (base
) == MEM_REF
)
3093 if (TREE_CODE (rbase
) != MEM_REF
)
3095 // Compare pointers.
3096 offset
+= mem_ref_offset (base
) << LOG2_BITS_PER_UNIT
;
3097 roffset
+= mem_ref_offset (rbase
) << LOG2_BITS_PER_UNIT
;
3098 base
= TREE_OPERAND (base
, 0);
3099 rbase
= TREE_OPERAND (rbase
, 0);
3102 && known_subrange_p (roffset
, ref
->max_size
, offset
,
3103 wi::to_poly_offset (len
)
3104 << LOG2_BITS_PER_UNIT
))
3109 case BUILT_IN_VA_END
:
3111 tree ptr
= gimple_call_arg (stmt
, 0);
3112 if (TREE_CODE (ptr
) == ADDR_EXPR
)
3114 tree base
= ao_ref_base (ref
);
3115 if (TREE_OPERAND (ptr
, 0) == base
)
3128 stmt_kills_ref_p (gimple
*stmt
, tree ref
)
3131 ao_ref_init (&r
, ref
);
3132 return stmt_kills_ref_p (stmt
, &r
);
3136 /* Walk the virtual use-def chain of VUSE until hitting the virtual operand
3137 TARGET or a statement clobbering the memory reference REF in which
3138 case false is returned. The walk starts with VUSE, one argument of PHI. */
3141 maybe_skip_until (gimple
*phi
, tree
&target
, basic_block target_bb
,
3142 ao_ref
*ref
, tree vuse
, bool tbaa_p
, unsigned int &limit
,
3143 bitmap
*visited
, bool abort_on_visited
,
3144 void *(*translate
)(ao_ref
*, tree
, void *, bool *),
3147 basic_block bb
= gimple_bb (phi
);
3150 *visited
= BITMAP_ALLOC (NULL
);
3152 bitmap_set_bit (*visited
, SSA_NAME_VERSION (PHI_RESULT (phi
)));
3154 /* Walk until we hit the target. */
3155 while (vuse
!= target
)
3157 gimple
*def_stmt
= SSA_NAME_DEF_STMT (vuse
);
3158 /* If we are searching for the target VUSE by walking up to
3159 TARGET_BB dominating the original PHI we are finished once
3160 we reach a default def or a definition in a block dominating
3161 that block. Update TARGET and return. */
3163 && (gimple_nop_p (def_stmt
)
3164 || dominated_by_p (CDI_DOMINATORS
,
3165 target_bb
, gimple_bb (def_stmt
))))
3171 /* Recurse for PHI nodes. */
3172 if (gimple_code (def_stmt
) == GIMPLE_PHI
)
3174 /* An already visited PHI node ends the walk successfully. */
3175 if (bitmap_bit_p (*visited
, SSA_NAME_VERSION (PHI_RESULT (def_stmt
))))
3176 return !abort_on_visited
;
3177 vuse
= get_continuation_for_phi (def_stmt
, ref
, tbaa_p
, limit
,
3178 visited
, abort_on_visited
,
3184 else if (gimple_nop_p (def_stmt
))
3188 /* A clobbering statement or the end of the IL ends it failing. */
3189 if ((int)limit
<= 0)
3192 if (stmt_may_clobber_ref_p_1 (def_stmt
, ref
, tbaa_p
))
3194 bool disambiguate_only
= true;
3196 && (*translate
) (ref
, vuse
, data
, &disambiguate_only
) == NULL
)
3202 /* If we reach a new basic-block see if we already skipped it
3203 in a previous walk that ended successfully. */
3204 if (gimple_bb (def_stmt
) != bb
)
3206 if (!bitmap_set_bit (*visited
, SSA_NAME_VERSION (vuse
)))
3207 return !abort_on_visited
;
3208 bb
= gimple_bb (def_stmt
);
3210 vuse
= gimple_vuse (def_stmt
);
3216 /* Starting from a PHI node for the virtual operand of the memory reference
3217 REF find a continuation virtual operand that allows to continue walking
3218 statements dominating PHI skipping only statements that cannot possibly
3219 clobber REF. Decrements LIMIT for each alias disambiguation done
3220 and aborts the walk, returning NULL_TREE if it reaches zero.
3221 Returns NULL_TREE if no suitable virtual operand can be found. */
3224 get_continuation_for_phi (gimple
*phi
, ao_ref
*ref
, bool tbaa_p
,
3225 unsigned int &limit
, bitmap
*visited
,
3226 bool abort_on_visited
,
3227 void *(*translate
)(ao_ref
*, tree
, void *, bool *),
3230 unsigned nargs
= gimple_phi_num_args (phi
);
3232 /* Through a single-argument PHI we can simply look through. */
3234 return PHI_ARG_DEF (phi
, 0);
3236 /* For two or more arguments try to pairwise skip non-aliasing code
3237 until we hit the phi argument definition that dominates the other one. */
3238 basic_block phi_bb
= gimple_bb (phi
);
3242 /* Find a candidate for the virtual operand which definition
3243 dominates those of all others. */
3244 /* First look if any of the args themselves satisfy this. */
3245 for (i
= 0; i
< nargs
; ++i
)
3247 arg0
= PHI_ARG_DEF (phi
, i
);
3248 if (SSA_NAME_IS_DEFAULT_DEF (arg0
))
3250 basic_block def_bb
= gimple_bb (SSA_NAME_DEF_STMT (arg0
));
3251 if (def_bb
!= phi_bb
3252 && dominated_by_p (CDI_DOMINATORS
, phi_bb
, def_bb
))
3256 /* If not, look if we can reach such candidate by walking defs
3257 until we hit the immediate dominator. maybe_skip_until will
3259 basic_block dom
= get_immediate_dominator (CDI_DOMINATORS
, phi_bb
);
3261 /* Then check against the (to be) found candidate. */
3262 for (i
= 0; i
< nargs
; ++i
)
3264 arg1
= PHI_ARG_DEF (phi
, i
);
3267 else if (! maybe_skip_until (phi
, arg0
, dom
, ref
, arg1
, tbaa_p
,
3270 /* Do not translate when walking over
3274 gimple_bb (SSA_NAME_DEF_STMT (arg1
)),
3276 ? NULL
: translate
, data
))
3283 /* Based on the memory reference REF and its virtual use VUSE call
3284 WALKER for each virtual use that is equivalent to VUSE, including VUSE
3285 itself. That is, for each virtual use for which its defining statement
3286 does not clobber REF.
3288 WALKER is called with REF, the current virtual use and DATA. If
3289 WALKER returns non-NULL the walk stops and its result is returned.
3290 At the end of a non-successful walk NULL is returned.
3292 TRANSLATE if non-NULL is called with a pointer to REF, the virtual
3293 use which definition is a statement that may clobber REF and DATA.
3294 If TRANSLATE returns (void *)-1 the walk stops and NULL is returned.
3295 If TRANSLATE returns non-NULL the walk stops and its result is returned.
3296 If TRANSLATE returns NULL the walk continues and TRANSLATE is supposed
3297 to adjust REF and *DATA to make that valid.
3299 VALUEIZE if non-NULL is called with the next VUSE that is considered
3300 and return value is substituted for that. This can be used to
3301 implement optimistic value-numbering for example. Note that the
3302 VUSE argument is assumed to be valueized already.
3304 LIMIT specifies the number of alias queries we are allowed to do,
3305 the walk stops when it reaches zero and NULL is returned. LIMIT
3306 is decremented by the number of alias queries (plus adjustments
3307 done by the callbacks) upon return.
3309 TODO: Cache the vector of equivalent vuses per ref, vuse pair. */
3312 walk_non_aliased_vuses (ao_ref
*ref
, tree vuse
, bool tbaa_p
,
3313 void *(*walker
)(ao_ref
*, tree
, void *),
3314 void *(*translate
)(ao_ref
*, tree
, void *, bool *),
3315 tree (*valueize
)(tree
),
3316 unsigned &limit
, void *data
)
3318 bitmap visited
= NULL
;
3320 bool translated
= false;
3322 timevar_push (TV_ALIAS_STMT_WALK
);
3328 /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */
3329 res
= (*walker
) (ref
, vuse
, data
);
3331 if (res
== (void *)-1)
3336 /* Lookup succeeded. */
3337 else if (res
!= NULL
)
3342 vuse
= valueize (vuse
);
3349 def_stmt
= SSA_NAME_DEF_STMT (vuse
);
3350 if (gimple_nop_p (def_stmt
))
3352 else if (gimple_code (def_stmt
) == GIMPLE_PHI
)
3353 vuse
= get_continuation_for_phi (def_stmt
, ref
, tbaa_p
, limit
,
3354 &visited
, translated
, translate
, data
);
3357 if ((int)limit
<= 0)
3363 if (stmt_may_clobber_ref_p_1 (def_stmt
, ref
, tbaa_p
))
3367 bool disambiguate_only
= false;
3368 res
= (*translate
) (ref
, vuse
, data
, &disambiguate_only
);
3369 /* Failed lookup and translation. */
3370 if (res
== (void *)-1)
3375 /* Lookup succeeded. */
3376 else if (res
!= NULL
)
3378 /* Translation succeeded, continue walking. */
3379 translated
= translated
|| !disambiguate_only
;
3381 vuse
= gimple_vuse (def_stmt
);
3387 BITMAP_FREE (visited
);
3389 timevar_pop (TV_ALIAS_STMT_WALK
);
3395 /* Based on the memory reference REF call WALKER for each vdef which
3396 defining statement may clobber REF, starting with VDEF. If REF
3397 is NULL_TREE, each defining statement is visited.
3399 WALKER is called with REF, the current vdef and DATA. If WALKER
3400 returns true the walk is stopped, otherwise it continues.
3402 If function entry is reached, FUNCTION_ENTRY_REACHED is set to true.
3403 The pointer may be NULL and then we do not track this information.
3405 At PHI nodes walk_aliased_vdefs forks into one walk for reach
3406 PHI argument (but only one walk continues on merge points), the
3407 return value is true if any of the walks was successful.
3409 The function returns the number of statements walked or -1 if
3410 LIMIT stmts were walked and the walk was aborted at this point.
3411 If LIMIT is zero the walk is not aborted. */
3414 walk_aliased_vdefs_1 (ao_ref
*ref
, tree vdef
,
3415 bool (*walker
)(ao_ref
*, tree
, void *), void *data
,
3416 bitmap
*visited
, unsigned int cnt
,
3417 bool *function_entry_reached
, unsigned limit
)
3421 gimple
*def_stmt
= SSA_NAME_DEF_STMT (vdef
);
3424 && !bitmap_set_bit (*visited
, SSA_NAME_VERSION (vdef
)))
3427 if (gimple_nop_p (def_stmt
))
3429 if (function_entry_reached
)
3430 *function_entry_reached
= true;
3433 else if (gimple_code (def_stmt
) == GIMPLE_PHI
)
3437 *visited
= BITMAP_ALLOC (NULL
);
3438 for (i
= 0; i
< gimple_phi_num_args (def_stmt
); ++i
)
3440 int res
= walk_aliased_vdefs_1 (ref
,
3441 gimple_phi_arg_def (def_stmt
, i
),
3442 walker
, data
, visited
, cnt
,
3443 function_entry_reached
, limit
);
3451 /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */
3456 || stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
3457 && (*walker
) (ref
, vdef
, data
))
3460 vdef
= gimple_vuse (def_stmt
);
3466 walk_aliased_vdefs (ao_ref
*ref
, tree vdef
,
3467 bool (*walker
)(ao_ref
*, tree
, void *), void *data
,
3469 bool *function_entry_reached
, unsigned int limit
)
3471 bitmap local_visited
= NULL
;
3474 timevar_push (TV_ALIAS_STMT_WALK
);
3476 if (function_entry_reached
)
3477 *function_entry_reached
= false;
3479 ret
= walk_aliased_vdefs_1 (ref
, vdef
, walker
, data
,
3480 visited
? visited
: &local_visited
, 0,
3481 function_entry_reached
, limit
);
3483 BITMAP_FREE (local_visited
);
3485 timevar_pop (TV_ALIAS_STMT_WALK
);