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);
1268 if (TREE_CODE (ref1
) == MEM_REF
&& ref1
!= match1
)
1270 if (!integer_zerop (TREE_OPERAND (ref1
, 1)))
1272 ++alias_stats
.nonoverlapping_component_refs_since_match_p_may_alias
;
1276 /* TODO: Handle TARGET_MEM_REF later. */
1277 if (TREE_CODE (ref1
) == TARGET_MEM_REF
&& ref1
!= match1
)
1279 ++alias_stats
.nonoverlapping_component_refs_since_match_p_may_alias
;
1283 /* Create the stack of handled components for REF2. */
1284 while (handled_component_p (ref2
) && ref2
!= match2
)
1286 if (TREE_CODE (ref2
) == VIEW_CONVERT_EXPR
1287 || TREE_CODE (ref2
) == BIT_FIELD_REF
)
1288 component_refs2
.truncate (0);
1290 component_refs2
.safe_push (ref2
);
1291 ref2
= TREE_OPERAND (ref2
, 0);
1293 if (TREE_CODE (ref2
) == MEM_REF
&& ref2
!= match2
)
1295 if (!integer_zerop (TREE_OPERAND (ref2
, 1)))
1297 ++alias_stats
.nonoverlapping_component_refs_since_match_p_may_alias
;
1301 if (TREE_CODE (ref2
) == TARGET_MEM_REF
&& ref2
!= match2
)
1303 ++alias_stats
.nonoverlapping_component_refs_since_match_p_may_alias
;
1307 /* Pop the stacks in parallel and examine the COMPONENT_REFs of the same
1308 rank. This is sufficient because we start from the same DECL and you
1309 cannot reference several fields at a time with COMPONENT_REFs (unlike
1310 with ARRAY_RANGE_REFs for arrays) so you always need the same number
1311 of them to access a sub-component, unless you're in a union, in which
1312 case the return value will precisely be false. */
1315 bool seen_noncomponent_ref_p
= false;
1318 if (component_refs1
.is_empty ())
1321 .nonoverlapping_component_refs_since_match_p_must_overlap
;
1324 ref1
= component_refs1
.pop ();
1325 if (TREE_CODE (ref1
) != COMPONENT_REF
)
1326 seen_noncomponent_ref_p
= true;
1328 while (!RECORD_OR_UNION_TYPE_P (TREE_TYPE (TREE_OPERAND (ref1
, 0))));
1332 if (component_refs2
.is_empty ())
1335 .nonoverlapping_component_refs_since_match_p_must_overlap
;
1338 ref2
= component_refs2
.pop ();
1339 if (TREE_CODE (ref2
) != COMPONENT_REF
)
1340 seen_noncomponent_ref_p
= true;
1342 while (!RECORD_OR_UNION_TYPE_P (TREE_TYPE (TREE_OPERAND (ref2
, 0))));
1344 /* BIT_FIELD_REF and VIEW_CONVERT_EXPR are taken off the vectors
1346 gcc_checking_assert (TREE_CODE (ref1
) == COMPONENT_REF
1347 && TREE_CODE (ref2
) == COMPONENT_REF
);
1349 tree field1
= TREE_OPERAND (ref1
, 1);
1350 tree field2
= TREE_OPERAND (ref2
, 1);
1352 /* ??? We cannot simply use the type of operand #0 of the refs here
1353 as the Fortran compiler smuggles type punning into COMPONENT_REFs
1354 for common blocks instead of using unions like everyone else. */
1355 tree type1
= DECL_CONTEXT (field1
);
1356 tree type2
= DECL_CONTEXT (field2
);
1358 /* If we skipped array refs on type of different sizes, we can
1359 no longer be sure that there are not partial overlaps. */
1360 if (seen_noncomponent_ref_p
1361 && !operand_equal_p (TYPE_SIZE (type1
), TYPE_SIZE (type2
), 0))
1364 .nonoverlapping_component_refs_since_match_p_may_alias
;
1368 int cmp
= nonoverlapping_component_refs_p_1 (field1
, field2
);
1372 .nonoverlapping_component_refs_since_match_p_may_alias
;
1378 .nonoverlapping_component_refs_since_match_p_no_alias
;
1383 ++alias_stats
.nonoverlapping_component_refs_since_match_p_must_overlap
;
1387 /* Return TYPE_UID which can be used to match record types we consider
1388 same for TBAA purposes. */
1391 ncr_type_uid (const_tree field
)
1393 /* ??? We cannot simply use the type of operand #0 of the refs here
1394 as the Fortran compiler smuggles type punning into COMPONENT_REFs
1395 for common blocks instead of using unions like everyone else. */
1396 tree type
= DECL_FIELD_CONTEXT (field
);
1397 /* With LTO types considered same_type_for_tbaa_p
1398 from different translation unit may not have same
1399 main variant. They however have same TYPE_CANONICAL. */
1400 if (TYPE_CANONICAL (type
))
1401 return TYPE_UID (TYPE_CANONICAL (type
));
1402 return TYPE_UID (type
);
1405 /* qsort compare function to sort FIELD_DECLs after their
1406 DECL_FIELD_CONTEXT TYPE_UID. */
1409 ncr_compar (const void *field1_
, const void *field2_
)
1411 const_tree field1
= *(const_tree
*) const_cast <void *>(field1_
);
1412 const_tree field2
= *(const_tree
*) const_cast <void *>(field2_
);
1413 unsigned int uid1
= ncr_type_uid (field1
);
1414 unsigned int uid2
= ncr_type_uid (field2
);
1418 else if (uid1
> uid2
)
1423 /* Return true if we can determine that the fields referenced cannot
1424 overlap for any pair of objects. This relies on TBAA. */
1427 nonoverlapping_component_refs_p (const_tree x
, const_tree y
)
1429 /* Early return if we have nothing to do.
1431 Do not consider this as may-alias for stats - it is more useful
1432 to have information how many disambiguations happened provided that
1433 the query was meaningful. */
1434 if (!flag_strict_aliasing
1436 || !handled_component_p (x
)
1437 || !handled_component_p (y
))
1440 auto_vec
<const_tree
, 16> fieldsx
;
1441 while (handled_component_p (x
))
1443 if (TREE_CODE (x
) == COMPONENT_REF
)
1445 tree field
= TREE_OPERAND (x
, 1);
1446 tree type
= DECL_FIELD_CONTEXT (field
);
1447 if (TREE_CODE (type
) == RECORD_TYPE
)
1448 fieldsx
.safe_push (field
);
1450 else if (TREE_CODE (x
) == VIEW_CONVERT_EXPR
1451 || TREE_CODE (x
) == BIT_FIELD_REF
)
1452 fieldsx
.truncate (0);
1453 x
= TREE_OPERAND (x
, 0);
1455 if (fieldsx
.length () == 0)
1457 auto_vec
<const_tree
, 16> fieldsy
;
1458 while (handled_component_p (y
))
1460 if (TREE_CODE (y
) == COMPONENT_REF
)
1462 tree field
= TREE_OPERAND (y
, 1);
1463 tree type
= DECL_FIELD_CONTEXT (field
);
1464 if (TREE_CODE (type
) == RECORD_TYPE
)
1465 fieldsy
.safe_push (TREE_OPERAND (y
, 1));
1467 else if (TREE_CODE (y
) == VIEW_CONVERT_EXPR
1468 || TREE_CODE (y
) == BIT_FIELD_REF
)
1469 fieldsy
.truncate (0);
1470 y
= TREE_OPERAND (y
, 0);
1472 if (fieldsy
.length () == 0)
1474 ++alias_stats
.nonoverlapping_component_refs_p_may_alias
;
1478 /* Most common case first. */
1479 if (fieldsx
.length () == 1
1480 && fieldsy
.length () == 1)
1482 if (same_type_for_tbaa (DECL_FIELD_CONTEXT (fieldsx
[0]),
1483 DECL_FIELD_CONTEXT (fieldsy
[0])) == 1
1484 && nonoverlapping_component_refs_p_1 (fieldsx
[0], fieldsy
[0]) == 1)
1486 ++alias_stats
.nonoverlapping_component_refs_p_no_alias
;
1491 ++alias_stats
.nonoverlapping_component_refs_p_may_alias
;
1496 if (fieldsx
.length () == 2)
1498 if (ncr_compar (&fieldsx
[0], &fieldsx
[1]) == 1)
1499 std::swap (fieldsx
[0], fieldsx
[1]);
1502 fieldsx
.qsort (ncr_compar
);
1504 if (fieldsy
.length () == 2)
1506 if (ncr_compar (&fieldsy
[0], &fieldsy
[1]) == 1)
1507 std::swap (fieldsy
[0], fieldsy
[1]);
1510 fieldsy
.qsort (ncr_compar
);
1512 unsigned i
= 0, j
= 0;
1515 const_tree fieldx
= fieldsx
[i
];
1516 const_tree fieldy
= fieldsy
[j
];
1518 /* We're left with accessing different fields of a structure,
1519 no possible overlap. */
1520 if (same_type_for_tbaa (DECL_FIELD_CONTEXT (fieldx
),
1521 DECL_FIELD_CONTEXT (fieldy
)) == 1
1522 && nonoverlapping_component_refs_p_1 (fieldx
, fieldy
) == 1)
1524 ++alias_stats
.nonoverlapping_component_refs_p_no_alias
;
1528 if (ncr_type_uid (fieldx
) < ncr_type_uid (fieldy
))
1531 if (i
== fieldsx
.length ())
1537 if (j
== fieldsy
.length ())
1543 ++alias_stats
.nonoverlapping_component_refs_p_may_alias
;
1548 /* Return true if two memory references based on the variables BASE1
1549 and BASE2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and
1550 [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. REF1 and REF2
1551 if non-NULL are the complete memory reference trees. */
1554 decl_refs_may_alias_p (tree ref1
, tree base1
,
1555 poly_int64 offset1
, poly_int64 max_size1
,
1557 tree ref2
, tree base2
,
1558 poly_int64 offset2
, poly_int64 max_size2
,
1561 gcc_checking_assert (DECL_P (base1
) && DECL_P (base2
));
1563 /* If both references are based on different variables, they cannot alias. */
1564 if (compare_base_decls (base1
, base2
) == 0)
1567 /* If both references are based on the same variable, they cannot alias if
1568 the accesses do not overlap. */
1569 if (!ranges_maybe_overlap_p (offset1
, max_size1
, offset2
, max_size2
))
1572 /* If there is must alias, there is no use disambiguating further. */
1573 if (known_eq (size1
, max_size1
) && known_eq (size2
, max_size2
))
1576 /* For components with variable position, the above test isn't sufficient,
1577 so we disambiguate component references manually. */
1579 && handled_component_p (ref1
) && handled_component_p (ref2
)
1580 && nonoverlapping_component_refs_since_match_p (NULL
, ref1
,
1587 /* Return true if an indirect reference based on *PTR1 constrained
1588 to [OFFSET1, OFFSET1 + MAX_SIZE1) may alias a variable based on BASE2
1589 constrained to [OFFSET2, OFFSET2 + MAX_SIZE2). *PTR1 and BASE2 have
1590 the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1
1591 in which case they are computed on-demand. REF1 and REF2
1592 if non-NULL are the complete memory reference trees. */
1595 indirect_ref_may_alias_decl_p (tree ref1 ATTRIBUTE_UNUSED
, tree base1
,
1596 poly_int64 offset1
, poly_int64 max_size1
,
1598 alias_set_type ref1_alias_set
,
1599 alias_set_type base1_alias_set
,
1600 tree ref2 ATTRIBUTE_UNUSED
, tree base2
,
1601 poly_int64 offset2
, poly_int64 max_size2
,
1603 alias_set_type ref2_alias_set
,
1604 alias_set_type base2_alias_set
, bool tbaa_p
)
1607 tree ptrtype1
, dbase2
;
1609 gcc_checking_assert ((TREE_CODE (base1
) == MEM_REF
1610 || TREE_CODE (base1
) == TARGET_MEM_REF
)
1613 ptr1
= TREE_OPERAND (base1
, 0);
1614 poly_offset_int moff
= mem_ref_offset (base1
) << LOG2_BITS_PER_UNIT
;
1616 /* If only one reference is based on a variable, they cannot alias if
1617 the pointer access is beyond the extent of the variable access.
1618 (the pointer base cannot validly point to an offset less than zero
1620 ??? IVOPTs creates bases that do not honor this restriction,
1621 so do not apply this optimization for TARGET_MEM_REFs. */
1622 if (TREE_CODE (base1
) != TARGET_MEM_REF
1623 && !ranges_maybe_overlap_p (offset1
+ moff
, -1, offset2
, max_size2
))
1625 /* They also cannot alias if the pointer may not point to the decl. */
1626 if (!ptr_deref_may_alias_decl_p (ptr1
, base2
))
1629 /* Disambiguations that rely on strict aliasing rules follow. */
1630 if (!flag_strict_aliasing
|| !tbaa_p
)
1633 /* If the alias set for a pointer access is zero all bets are off. */
1634 if (base1_alias_set
== 0 || base2_alias_set
== 0)
1637 /* When we are trying to disambiguate an access with a pointer dereference
1638 as base versus one with a decl as base we can use both the size
1639 of the decl and its dynamic type for extra disambiguation.
1640 ??? We do not know anything about the dynamic type of the decl
1641 other than that its alias-set contains base2_alias_set as a subset
1642 which does not help us here. */
1643 /* As we know nothing useful about the dynamic type of the decl just
1644 use the usual conflict check rather than a subset test.
1645 ??? We could introduce -fvery-strict-aliasing when the language
1646 does not allow decls to have a dynamic type that differs from their
1647 static type. Then we can check
1648 !alias_set_subset_of (base1_alias_set, base2_alias_set) instead. */
1649 if (base1_alias_set
!= base2_alias_set
1650 && !alias_sets_conflict_p (base1_alias_set
, base2_alias_set
))
1653 ptrtype1
= TREE_TYPE (TREE_OPERAND (base1
, 1));
1655 /* If the size of the access relevant for TBAA through the pointer
1656 is bigger than the size of the decl we can't possibly access the
1657 decl via that pointer. */
1658 if (/* ??? This in turn may run afoul when a decl of type T which is
1659 a member of union type U is accessed through a pointer to
1660 type U and sizeof T is smaller than sizeof U. */
1661 TREE_CODE (TREE_TYPE (ptrtype1
)) != UNION_TYPE
1662 && TREE_CODE (TREE_TYPE (ptrtype1
)) != QUAL_UNION_TYPE
1663 && compare_sizes (DECL_SIZE (base2
),
1664 TYPE_SIZE (TREE_TYPE (ptrtype1
))) < 0)
1670 /* If the decl is accessed via a MEM_REF, reconstruct the base
1671 we can use for TBAA and an appropriately adjusted offset. */
1673 while (handled_component_p (dbase2
))
1674 dbase2
= TREE_OPERAND (dbase2
, 0);
1675 poly_int64 doffset1
= offset1
;
1676 poly_offset_int doffset2
= offset2
;
1677 if (TREE_CODE (dbase2
) == MEM_REF
1678 || TREE_CODE (dbase2
) == TARGET_MEM_REF
)
1680 doffset2
-= mem_ref_offset (dbase2
) << LOG2_BITS_PER_UNIT
;
1681 tree ptrtype2
= TREE_TYPE (TREE_OPERAND (dbase2
, 1));
1682 /* If second reference is view-converted, give up now. */
1683 if (same_type_for_tbaa (TREE_TYPE (dbase2
), TREE_TYPE (ptrtype2
)) != 1)
1687 /* If first reference is view-converted, give up now. */
1688 if (same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (ptrtype1
)) != 1)
1691 /* If both references are through the same type, they do not alias
1692 if the accesses do not overlap. This does extra disambiguation
1693 for mixed/pointer accesses but requires strict aliasing.
1694 For MEM_REFs we require that the component-ref offset we computed
1695 is relative to the start of the type which we ensure by
1696 comparing rvalue and access type and disregarding the constant
1699 But avoid treating variable length arrays as "objects", instead assume they
1700 can overlap by an exact multiple of their element size.
1701 See gcc.dg/torture/alias-2.c. */
1702 if (((TREE_CODE (base1
) != TARGET_MEM_REF
1703 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1704 && (TREE_CODE (dbase2
) != TARGET_MEM_REF
1705 || (!TMR_INDEX (dbase2
) && !TMR_INDEX2 (dbase2
))))
1706 && same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (dbase2
)) == 1
1707 && (TREE_CODE (TREE_TYPE (base1
)) != ARRAY_TYPE
1708 || (TYPE_SIZE (TREE_TYPE (base1
))
1709 && TREE_CODE (TYPE_SIZE (TREE_TYPE (base1
))) == INTEGER_CST
)))
1711 if (!ranges_maybe_overlap_p (doffset1
, max_size1
, doffset2
, max_size2
))
1714 /* If there is must alias, there is no use disambiguating further. */
1715 || (known_eq (size1
, max_size1
) && known_eq (size2
, max_size2
)))
1717 int res
= nonoverlapping_component_refs_since_match_p (base1
, ref1
,
1720 return !nonoverlapping_component_refs_p (ref1
, ref2
);
1724 /* Do access-path based disambiguation. */
1726 && (handled_component_p (ref1
) || handled_component_p (ref2
)))
1727 return aliasing_component_refs_p (ref1
,
1728 ref1_alias_set
, base1_alias_set
,
1731 ref2_alias_set
, base2_alias_set
,
1732 offset2
, max_size2
);
1737 /* Return true if two indirect references based on *PTR1
1738 and *PTR2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and
1739 [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. *PTR1 and *PTR2 have
1740 the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1
1741 in which case they are computed on-demand. REF1 and REF2
1742 if non-NULL are the complete memory reference trees. */
1745 indirect_refs_may_alias_p (tree ref1 ATTRIBUTE_UNUSED
, tree base1
,
1746 poly_int64 offset1
, poly_int64 max_size1
,
1748 alias_set_type ref1_alias_set
,
1749 alias_set_type base1_alias_set
,
1750 tree ref2 ATTRIBUTE_UNUSED
, tree base2
,
1751 poly_int64 offset2
, poly_int64 max_size2
,
1753 alias_set_type ref2_alias_set
,
1754 alias_set_type base2_alias_set
, bool tbaa_p
)
1758 tree ptrtype1
, ptrtype2
;
1760 gcc_checking_assert ((TREE_CODE (base1
) == MEM_REF
1761 || TREE_CODE (base1
) == TARGET_MEM_REF
)
1762 && (TREE_CODE (base2
) == MEM_REF
1763 || TREE_CODE (base2
) == TARGET_MEM_REF
));
1765 ptr1
= TREE_OPERAND (base1
, 0);
1766 ptr2
= TREE_OPERAND (base2
, 0);
1768 /* If both bases are based on pointers they cannot alias if they may not
1769 point to the same memory object or if they point to the same object
1770 and the accesses do not overlap. */
1771 if ((!cfun
|| gimple_in_ssa_p (cfun
))
1772 && operand_equal_p (ptr1
, ptr2
, 0)
1773 && (((TREE_CODE (base1
) != TARGET_MEM_REF
1774 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1775 && (TREE_CODE (base2
) != TARGET_MEM_REF
1776 || (!TMR_INDEX (base2
) && !TMR_INDEX2 (base2
))))
1777 || (TREE_CODE (base1
) == TARGET_MEM_REF
1778 && TREE_CODE (base2
) == TARGET_MEM_REF
1779 && (TMR_STEP (base1
) == TMR_STEP (base2
)
1780 || (TMR_STEP (base1
) && TMR_STEP (base2
)
1781 && operand_equal_p (TMR_STEP (base1
),
1782 TMR_STEP (base2
), 0)))
1783 && (TMR_INDEX (base1
) == TMR_INDEX (base2
)
1784 || (TMR_INDEX (base1
) && TMR_INDEX (base2
)
1785 && operand_equal_p (TMR_INDEX (base1
),
1786 TMR_INDEX (base2
), 0)))
1787 && (TMR_INDEX2 (base1
) == TMR_INDEX2 (base2
)
1788 || (TMR_INDEX2 (base1
) && TMR_INDEX2 (base2
)
1789 && operand_equal_p (TMR_INDEX2 (base1
),
1790 TMR_INDEX2 (base2
), 0))))))
1792 poly_offset_int moff1
= mem_ref_offset (base1
) << LOG2_BITS_PER_UNIT
;
1793 poly_offset_int moff2
= mem_ref_offset (base2
) << LOG2_BITS_PER_UNIT
;
1794 if (!ranges_maybe_overlap_p (offset1
+ moff1
, max_size1
,
1795 offset2
+ moff2
, max_size2
))
1797 /* If there is must alias, there is no use disambiguating further. */
1798 if (known_eq (size1
, max_size1
) && known_eq (size2
, max_size2
))
1802 int res
= nonoverlapping_component_refs_since_match_p (NULL
, ref1
,
1808 if (!ptr_derefs_may_alias_p (ptr1
, ptr2
))
1811 /* Disambiguations that rely on strict aliasing rules follow. */
1812 if (!flag_strict_aliasing
|| !tbaa_p
)
1815 ptrtype1
= TREE_TYPE (TREE_OPERAND (base1
, 1));
1816 ptrtype2
= TREE_TYPE (TREE_OPERAND (base2
, 1));
1818 /* If the alias set for a pointer access is zero all bets are off. */
1819 if (base1_alias_set
== 0
1820 || base2_alias_set
== 0)
1823 /* Do type-based disambiguation. */
1824 if (base1_alias_set
!= base2_alias_set
1825 && !alias_sets_conflict_p (base1_alias_set
, base2_alias_set
))
1828 /* If either reference is view-converted, give up now. */
1829 if (same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (ptrtype1
)) != 1
1830 || same_type_for_tbaa (TREE_TYPE (base2
), TREE_TYPE (ptrtype2
)) != 1)
1833 /* If both references are through the same type, they do not alias
1834 if the accesses do not overlap. This does extra disambiguation
1835 for mixed/pointer accesses but requires strict aliasing. */
1836 if ((TREE_CODE (base1
) != TARGET_MEM_REF
1837 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1838 && (TREE_CODE (base2
) != TARGET_MEM_REF
1839 || (!TMR_INDEX (base2
) && !TMR_INDEX2 (base2
)))
1840 && same_type_for_tbaa (TREE_TYPE (ptrtype1
),
1841 TREE_TYPE (ptrtype2
)) == 1
1842 /* But avoid treating arrays as "objects", instead assume they
1843 can overlap by an exact multiple of their element size.
1844 See gcc.dg/torture/alias-2.c. */
1845 && TREE_CODE (TREE_TYPE (ptrtype1
)) != ARRAY_TYPE
)
1847 if (!ranges_maybe_overlap_p (offset1
, max_size1
, offset2
, max_size2
))
1850 || (known_eq (size1
, max_size1
) && known_eq (size2
, max_size2
)))
1852 int res
= nonoverlapping_component_refs_since_match_p (base1
, ref1
,
1855 return !nonoverlapping_component_refs_p (ref1
, ref2
);
1859 /* Do access-path based disambiguation. */
1861 && (handled_component_p (ref1
) || handled_component_p (ref2
)))
1862 return aliasing_component_refs_p (ref1
,
1863 ref1_alias_set
, base1_alias_set
,
1866 ref2_alias_set
, base2_alias_set
,
1867 offset2
, max_size2
);
1872 /* Return true, if the two memory references REF1 and REF2 may alias. */
1875 refs_may_alias_p_2 (ao_ref
*ref1
, ao_ref
*ref2
, bool tbaa_p
)
1878 poly_int64 offset1
= 0, offset2
= 0;
1879 poly_int64 max_size1
= -1, max_size2
= -1;
1880 bool var1_p
, var2_p
, ind1_p
, ind2_p
;
1882 gcc_checking_assert ((!ref1
->ref
1883 || TREE_CODE (ref1
->ref
) == SSA_NAME
1884 || DECL_P (ref1
->ref
)
1885 || TREE_CODE (ref1
->ref
) == STRING_CST
1886 || handled_component_p (ref1
->ref
)
1887 || TREE_CODE (ref1
->ref
) == MEM_REF
1888 || TREE_CODE (ref1
->ref
) == TARGET_MEM_REF
)
1890 || TREE_CODE (ref2
->ref
) == SSA_NAME
1891 || DECL_P (ref2
->ref
)
1892 || TREE_CODE (ref2
->ref
) == STRING_CST
1893 || handled_component_p (ref2
->ref
)
1894 || TREE_CODE (ref2
->ref
) == MEM_REF
1895 || TREE_CODE (ref2
->ref
) == TARGET_MEM_REF
));
1897 /* Decompose the references into their base objects and the access. */
1898 base1
= ao_ref_base (ref1
);
1899 offset1
= ref1
->offset
;
1900 max_size1
= ref1
->max_size
;
1901 base2
= ao_ref_base (ref2
);
1902 offset2
= ref2
->offset
;
1903 max_size2
= ref2
->max_size
;
1905 /* We can end up with registers or constants as bases for example from
1906 *D.1663_44 = VIEW_CONVERT_EXPR<struct DB_LSN>(__tmp$B0F64_59);
1907 which is seen as a struct copy. */
1908 if (TREE_CODE (base1
) == SSA_NAME
1909 || TREE_CODE (base1
) == CONST_DECL
1910 || TREE_CODE (base1
) == CONSTRUCTOR
1911 || TREE_CODE (base1
) == ADDR_EXPR
1912 || CONSTANT_CLASS_P (base1
)
1913 || TREE_CODE (base2
) == SSA_NAME
1914 || TREE_CODE (base2
) == CONST_DECL
1915 || TREE_CODE (base2
) == CONSTRUCTOR
1916 || TREE_CODE (base2
) == ADDR_EXPR
1917 || CONSTANT_CLASS_P (base2
))
1920 /* We can end up referring to code via function and label decls.
1921 As we likely do not properly track code aliases conservatively
1923 if (TREE_CODE (base1
) == FUNCTION_DECL
1924 || TREE_CODE (base1
) == LABEL_DECL
1925 || TREE_CODE (base2
) == FUNCTION_DECL
1926 || TREE_CODE (base2
) == LABEL_DECL
)
1929 /* Two volatile accesses always conflict. */
1930 if (ref1
->volatile_p
1931 && ref2
->volatile_p
)
1934 /* Defer to simple offset based disambiguation if we have
1935 references based on two decls. Do this before defering to
1936 TBAA to handle must-alias cases in conformance with the
1937 GCC extension of allowing type-punning through unions. */
1938 var1_p
= DECL_P (base1
);
1939 var2_p
= DECL_P (base2
);
1940 if (var1_p
&& var2_p
)
1941 return decl_refs_may_alias_p (ref1
->ref
, base1
, offset1
, max_size1
,
1943 ref2
->ref
, base2
, offset2
, max_size2
,
1946 /* Handle restrict based accesses.
1947 ??? ao_ref_base strips inner MEM_REF [&decl], recover from that
1949 tree rbase1
= base1
;
1950 tree rbase2
= base2
;
1955 while (handled_component_p (rbase1
))
1956 rbase1
= TREE_OPERAND (rbase1
, 0);
1962 while (handled_component_p (rbase2
))
1963 rbase2
= TREE_OPERAND (rbase2
, 0);
1965 if (rbase1
&& rbase2
1966 && (TREE_CODE (base1
) == MEM_REF
|| TREE_CODE (base1
) == TARGET_MEM_REF
)
1967 && (TREE_CODE (base2
) == MEM_REF
|| TREE_CODE (base2
) == TARGET_MEM_REF
)
1968 /* If the accesses are in the same restrict clique... */
1969 && MR_DEPENDENCE_CLIQUE (base1
) == MR_DEPENDENCE_CLIQUE (base2
)
1970 /* But based on different pointers they do not alias. */
1971 && MR_DEPENDENCE_BASE (base1
) != MR_DEPENDENCE_BASE (base2
))
1974 ind1_p
= (TREE_CODE (base1
) == MEM_REF
1975 || TREE_CODE (base1
) == TARGET_MEM_REF
);
1976 ind2_p
= (TREE_CODE (base2
) == MEM_REF
1977 || TREE_CODE (base2
) == TARGET_MEM_REF
);
1979 /* Canonicalize the pointer-vs-decl case. */
1980 if (ind1_p
&& var2_p
)
1982 std::swap (offset1
, offset2
);
1983 std::swap (max_size1
, max_size2
);
1984 std::swap (base1
, base2
);
1985 std::swap (ref1
, ref2
);
1992 /* First defer to TBAA if possible. */
1994 && flag_strict_aliasing
1995 && !alias_sets_conflict_p (ao_ref_alias_set (ref1
),
1996 ao_ref_alias_set (ref2
)))
1999 /* If the reference is based on a pointer that points to memory
2000 that may not be written to then the other reference cannot possibly
2002 if ((TREE_CODE (TREE_OPERAND (base2
, 0)) == SSA_NAME
2003 && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base2
, 0)))
2005 && TREE_CODE (TREE_OPERAND (base1
, 0)) == SSA_NAME
2006 && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base1
, 0))))
2009 /* Dispatch to the pointer-vs-decl or pointer-vs-pointer disambiguators. */
2010 if (var1_p
&& ind2_p
)
2011 return indirect_ref_may_alias_decl_p (ref2
->ref
, base2
,
2012 offset2
, max_size2
, ref2
->size
,
2013 ao_ref_alias_set (ref2
),
2014 ao_ref_base_alias_set (ref2
),
2016 offset1
, max_size1
, ref1
->size
,
2017 ao_ref_alias_set (ref1
),
2018 ao_ref_base_alias_set (ref1
),
2020 else if (ind1_p
&& ind2_p
)
2021 return indirect_refs_may_alias_p (ref1
->ref
, base1
,
2022 offset1
, max_size1
, ref1
->size
,
2023 ao_ref_alias_set (ref1
),
2024 ao_ref_base_alias_set (ref1
),
2026 offset2
, max_size2
, ref2
->size
,
2027 ao_ref_alias_set (ref2
),
2028 ao_ref_base_alias_set (ref2
),
2034 /* Return true, if the two memory references REF1 and REF2 may alias
2035 and update statistics. */
2038 refs_may_alias_p_1 (ao_ref
*ref1
, ao_ref
*ref2
, bool tbaa_p
)
2040 bool res
= refs_may_alias_p_2 (ref1
, ref2
, tbaa_p
);
2042 ++alias_stats
.refs_may_alias_p_may_alias
;
2044 ++alias_stats
.refs_may_alias_p_no_alias
;
2049 refs_may_alias_p (tree ref1
, ao_ref
*ref2
, bool tbaa_p
)
2052 ao_ref_init (&r1
, ref1
);
2053 return refs_may_alias_p_1 (&r1
, ref2
, tbaa_p
);
2057 refs_may_alias_p (tree ref1
, tree ref2
, bool tbaa_p
)
2060 ao_ref_init (&r1
, ref1
);
2061 ao_ref_init (&r2
, ref2
);
2062 return refs_may_alias_p_1 (&r1
, &r2
, tbaa_p
);
2065 /* Returns true if there is a anti-dependence for the STORE that
2066 executes after the LOAD. */
2069 refs_anti_dependent_p (tree load
, tree store
)
2072 ao_ref_init (&r1
, load
);
2073 ao_ref_init (&r2
, store
);
2074 return refs_may_alias_p_1 (&r1
, &r2
, false);
2077 /* Returns true if there is a output dependence for the stores
2078 STORE1 and STORE2. */
2081 refs_output_dependent_p (tree store1
, tree store2
)
2084 ao_ref_init (&r1
, store1
);
2085 ao_ref_init (&r2
, store2
);
2086 return refs_may_alias_p_1 (&r1
, &r2
, false);
2089 /* If the call CALL may use the memory reference REF return true,
2090 otherwise return false. */
2093 ref_maybe_used_by_call_p_1 (gcall
*call
, ao_ref
*ref
, bool tbaa_p
)
2097 int flags
= gimple_call_flags (call
);
2099 /* Const functions without a static chain do not implicitly use memory. */
2100 if (!gimple_call_chain (call
)
2101 && (flags
& (ECF_CONST
|ECF_NOVOPS
)))
2104 base
= ao_ref_base (ref
);
2108 /* A call that is not without side-effects might involve volatile
2109 accesses and thus conflicts with all other volatile accesses. */
2110 if (ref
->volatile_p
)
2113 /* If the reference is based on a decl that is not aliased the call
2114 cannot possibly use it. */
2116 && !may_be_aliased (base
)
2117 /* But local statics can be used through recursion. */
2118 && !is_global_var (base
))
2121 callee
= gimple_call_fndecl (call
);
2123 /* Handle those builtin functions explicitly that do not act as
2124 escape points. See tree-ssa-structalias.c:find_func_aliases
2125 for the list of builtins we might need to handle here. */
2126 if (callee
!= NULL_TREE
2127 && gimple_call_builtin_p (call
, BUILT_IN_NORMAL
))
2128 switch (DECL_FUNCTION_CODE (callee
))
2130 /* All the following functions read memory pointed to by
2131 their second argument. strcat/strncat additionally
2132 reads memory pointed to by the first argument. */
2133 case BUILT_IN_STRCAT
:
2134 case BUILT_IN_STRNCAT
:
2137 ao_ref_init_from_ptr_and_size (&dref
,
2138 gimple_call_arg (call
, 0),
2140 if (refs_may_alias_p_1 (&dref
, ref
, false))
2144 case BUILT_IN_STRCPY
:
2145 case BUILT_IN_STRNCPY
:
2146 case BUILT_IN_MEMCPY
:
2147 case BUILT_IN_MEMMOVE
:
2148 case BUILT_IN_MEMPCPY
:
2149 case BUILT_IN_STPCPY
:
2150 case BUILT_IN_STPNCPY
:
2151 case BUILT_IN_TM_MEMCPY
:
2152 case BUILT_IN_TM_MEMMOVE
:
2155 tree size
= NULL_TREE
;
2156 if (gimple_call_num_args (call
) == 3)
2157 size
= gimple_call_arg (call
, 2);
2158 ao_ref_init_from_ptr_and_size (&dref
,
2159 gimple_call_arg (call
, 1),
2161 return refs_may_alias_p_1 (&dref
, ref
, false);
2163 case BUILT_IN_STRCAT_CHK
:
2164 case BUILT_IN_STRNCAT_CHK
:
2167 ao_ref_init_from_ptr_and_size (&dref
,
2168 gimple_call_arg (call
, 0),
2170 if (refs_may_alias_p_1 (&dref
, ref
, false))
2174 case BUILT_IN_STRCPY_CHK
:
2175 case BUILT_IN_STRNCPY_CHK
:
2176 case BUILT_IN_MEMCPY_CHK
:
2177 case BUILT_IN_MEMMOVE_CHK
:
2178 case BUILT_IN_MEMPCPY_CHK
:
2179 case BUILT_IN_STPCPY_CHK
:
2180 case BUILT_IN_STPNCPY_CHK
:
2183 tree size
= NULL_TREE
;
2184 if (gimple_call_num_args (call
) == 4)
2185 size
= gimple_call_arg (call
, 2);
2186 ao_ref_init_from_ptr_and_size (&dref
,
2187 gimple_call_arg (call
, 1),
2189 return refs_may_alias_p_1 (&dref
, ref
, false);
2191 case BUILT_IN_BCOPY
:
2194 tree size
= gimple_call_arg (call
, 2);
2195 ao_ref_init_from_ptr_and_size (&dref
,
2196 gimple_call_arg (call
, 0),
2198 return refs_may_alias_p_1 (&dref
, ref
, false);
2201 /* The following functions read memory pointed to by their
2203 CASE_BUILT_IN_TM_LOAD (1):
2204 CASE_BUILT_IN_TM_LOAD (2):
2205 CASE_BUILT_IN_TM_LOAD (4):
2206 CASE_BUILT_IN_TM_LOAD (8):
2207 CASE_BUILT_IN_TM_LOAD (FLOAT
):
2208 CASE_BUILT_IN_TM_LOAD (DOUBLE
):
2209 CASE_BUILT_IN_TM_LOAD (LDOUBLE
):
2210 CASE_BUILT_IN_TM_LOAD (M64
):
2211 CASE_BUILT_IN_TM_LOAD (M128
):
2212 CASE_BUILT_IN_TM_LOAD (M256
):
2213 case BUILT_IN_TM_LOG
:
2214 case BUILT_IN_TM_LOG_1
:
2215 case BUILT_IN_TM_LOG_2
:
2216 case BUILT_IN_TM_LOG_4
:
2217 case BUILT_IN_TM_LOG_8
:
2218 case BUILT_IN_TM_LOG_FLOAT
:
2219 case BUILT_IN_TM_LOG_DOUBLE
:
2220 case BUILT_IN_TM_LOG_LDOUBLE
:
2221 case BUILT_IN_TM_LOG_M64
:
2222 case BUILT_IN_TM_LOG_M128
:
2223 case BUILT_IN_TM_LOG_M256
:
2224 return ptr_deref_may_alias_ref_p_1 (gimple_call_arg (call
, 0), ref
);
2226 /* These read memory pointed to by the first argument. */
2227 case BUILT_IN_STRDUP
:
2228 case BUILT_IN_STRNDUP
:
2229 case BUILT_IN_REALLOC
:
2232 tree size
= NULL_TREE
;
2233 if (gimple_call_num_args (call
) == 2)
2234 size
= gimple_call_arg (call
, 1);
2235 ao_ref_init_from_ptr_and_size (&dref
,
2236 gimple_call_arg (call
, 0),
2238 return refs_may_alias_p_1 (&dref
, ref
, false);
2240 /* These read memory pointed to by the first argument. */
2241 case BUILT_IN_INDEX
:
2242 case BUILT_IN_STRCHR
:
2243 case BUILT_IN_STRRCHR
:
2246 ao_ref_init_from_ptr_and_size (&dref
,
2247 gimple_call_arg (call
, 0),
2249 return refs_may_alias_p_1 (&dref
, ref
, false);
2251 /* These read memory pointed to by the first argument with size
2252 in the third argument. */
2253 case BUILT_IN_MEMCHR
:
2256 ao_ref_init_from_ptr_and_size (&dref
,
2257 gimple_call_arg (call
, 0),
2258 gimple_call_arg (call
, 2));
2259 return refs_may_alias_p_1 (&dref
, ref
, false);
2261 /* These read memory pointed to by the first and second arguments. */
2262 case BUILT_IN_STRSTR
:
2263 case BUILT_IN_STRPBRK
:
2266 ao_ref_init_from_ptr_and_size (&dref
,
2267 gimple_call_arg (call
, 0),
2269 if (refs_may_alias_p_1 (&dref
, ref
, false))
2271 ao_ref_init_from_ptr_and_size (&dref
,
2272 gimple_call_arg (call
, 1),
2274 return refs_may_alias_p_1 (&dref
, ref
, false);
2277 /* The following builtins do not read from memory. */
2279 case BUILT_IN_MALLOC
:
2280 case BUILT_IN_POSIX_MEMALIGN
:
2281 case BUILT_IN_ALIGNED_ALLOC
:
2282 case BUILT_IN_CALLOC
:
2283 CASE_BUILT_IN_ALLOCA
:
2284 case BUILT_IN_STACK_SAVE
:
2285 case BUILT_IN_STACK_RESTORE
:
2286 case BUILT_IN_MEMSET
:
2287 case BUILT_IN_TM_MEMSET
:
2288 case BUILT_IN_MEMSET_CHK
:
2289 case BUILT_IN_FREXP
:
2290 case BUILT_IN_FREXPF
:
2291 case BUILT_IN_FREXPL
:
2292 case BUILT_IN_GAMMA_R
:
2293 case BUILT_IN_GAMMAF_R
:
2294 case BUILT_IN_GAMMAL_R
:
2295 case BUILT_IN_LGAMMA_R
:
2296 case BUILT_IN_LGAMMAF_R
:
2297 case BUILT_IN_LGAMMAL_R
:
2299 case BUILT_IN_MODFF
:
2300 case BUILT_IN_MODFL
:
2301 case BUILT_IN_REMQUO
:
2302 case BUILT_IN_REMQUOF
:
2303 case BUILT_IN_REMQUOL
:
2304 case BUILT_IN_SINCOS
:
2305 case BUILT_IN_SINCOSF
:
2306 case BUILT_IN_SINCOSL
:
2307 case BUILT_IN_ASSUME_ALIGNED
:
2308 case BUILT_IN_VA_END
:
2310 /* __sync_* builtins and some OpenMP builtins act as threading
2312 #undef DEF_SYNC_BUILTIN
2313 #define DEF_SYNC_BUILTIN(ENUM, NAME, TYPE, ATTRS) case ENUM:
2314 #include "sync-builtins.def"
2315 #undef DEF_SYNC_BUILTIN
2316 case BUILT_IN_GOMP_ATOMIC_START
:
2317 case BUILT_IN_GOMP_ATOMIC_END
:
2318 case BUILT_IN_GOMP_BARRIER
:
2319 case BUILT_IN_GOMP_BARRIER_CANCEL
:
2320 case BUILT_IN_GOMP_TASKWAIT
:
2321 case BUILT_IN_GOMP_TASKGROUP_END
:
2322 case BUILT_IN_GOMP_CRITICAL_START
:
2323 case BUILT_IN_GOMP_CRITICAL_END
:
2324 case BUILT_IN_GOMP_CRITICAL_NAME_START
:
2325 case BUILT_IN_GOMP_CRITICAL_NAME_END
:
2326 case BUILT_IN_GOMP_LOOP_END
:
2327 case BUILT_IN_GOMP_LOOP_END_CANCEL
:
2328 case BUILT_IN_GOMP_ORDERED_START
:
2329 case BUILT_IN_GOMP_ORDERED_END
:
2330 case BUILT_IN_GOMP_SECTIONS_END
:
2331 case BUILT_IN_GOMP_SECTIONS_END_CANCEL
:
2332 case BUILT_IN_GOMP_SINGLE_COPY_START
:
2333 case BUILT_IN_GOMP_SINGLE_COPY_END
:
2337 /* Fallthru to general call handling. */;
2340 /* Check if base is a global static variable that is not read
2342 if (callee
!= NULL_TREE
&& VAR_P (base
) && TREE_STATIC (base
))
2344 struct cgraph_node
*node
= cgraph_node::get (callee
);
2347 /* FIXME: Callee can be an OMP builtin that does not have a call graph
2348 node yet. We should enforce that there are nodes for all decls in the
2349 IL and remove this check instead. */
2351 && (not_read
= ipa_reference_get_not_read_global (node
))
2352 && bitmap_bit_p (not_read
, ipa_reference_var_uid (base
)))
2356 /* Check if the base variable is call-used. */
2359 if (pt_solution_includes (gimple_call_use_set (call
), base
))
2362 else if ((TREE_CODE (base
) == MEM_REF
2363 || TREE_CODE (base
) == TARGET_MEM_REF
)
2364 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
)
2366 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (TREE_OPERAND (base
, 0));
2370 if (pt_solutions_intersect (gimple_call_use_set (call
), &pi
->pt
))
2376 /* Inspect call arguments for passed-by-value aliases. */
2378 for (i
= 0; i
< gimple_call_num_args (call
); ++i
)
2380 tree op
= gimple_call_arg (call
, i
);
2381 int flags
= gimple_call_arg_flags (call
, i
);
2383 if (flags
& EAF_UNUSED
)
2386 if (TREE_CODE (op
) == WITH_SIZE_EXPR
)
2387 op
= TREE_OPERAND (op
, 0);
2389 if (TREE_CODE (op
) != SSA_NAME
2390 && !is_gimple_min_invariant (op
))
2393 ao_ref_init (&r
, op
);
2394 if (refs_may_alias_p_1 (&r
, ref
, tbaa_p
))
2403 ref_maybe_used_by_call_p (gcall
*call
, ao_ref
*ref
, bool tbaa_p
)
2406 res
= ref_maybe_used_by_call_p_1 (call
, ref
, tbaa_p
);
2408 ++alias_stats
.ref_maybe_used_by_call_p_may_alias
;
2410 ++alias_stats
.ref_maybe_used_by_call_p_no_alias
;
2415 /* If the statement STMT may use the memory reference REF return
2416 true, otherwise return false. */
2419 ref_maybe_used_by_stmt_p (gimple
*stmt
, ao_ref
*ref
, bool tbaa_p
)
2421 if (is_gimple_assign (stmt
))
2425 /* All memory assign statements are single. */
2426 if (!gimple_assign_single_p (stmt
))
2429 rhs
= gimple_assign_rhs1 (stmt
);
2430 if (is_gimple_reg (rhs
)
2431 || is_gimple_min_invariant (rhs
)
2432 || gimple_assign_rhs_code (stmt
) == CONSTRUCTOR
)
2435 return refs_may_alias_p (rhs
, ref
, tbaa_p
);
2437 else if (is_gimple_call (stmt
))
2438 return ref_maybe_used_by_call_p (as_a
<gcall
*> (stmt
), ref
, tbaa_p
);
2439 else if (greturn
*return_stmt
= dyn_cast
<greturn
*> (stmt
))
2441 tree retval
= gimple_return_retval (return_stmt
);
2443 && TREE_CODE (retval
) != SSA_NAME
2444 && !is_gimple_min_invariant (retval
)
2445 && refs_may_alias_p (retval
, ref
, tbaa_p
))
2447 /* If ref escapes the function then the return acts as a use. */
2448 tree base
= ao_ref_base (ref
);
2451 else if (DECL_P (base
))
2452 return is_global_var (base
);
2453 else if (TREE_CODE (base
) == MEM_REF
2454 || TREE_CODE (base
) == TARGET_MEM_REF
)
2455 return ptr_deref_may_alias_global_p (TREE_OPERAND (base
, 0));
2463 ref_maybe_used_by_stmt_p (gimple
*stmt
, tree ref
, bool tbaa_p
)
2466 ao_ref_init (&r
, ref
);
2467 return ref_maybe_used_by_stmt_p (stmt
, &r
, tbaa_p
);
2470 /* If the call in statement CALL may clobber the memory reference REF
2471 return true, otherwise return false. */
2474 call_may_clobber_ref_p_1 (gcall
*call
, ao_ref
*ref
)
2479 /* If the call is pure or const it cannot clobber anything. */
2480 if (gimple_call_flags (call
)
2481 & (ECF_PURE
|ECF_CONST
|ECF_LOOPING_CONST_OR_PURE
|ECF_NOVOPS
))
2483 if (gimple_call_internal_p (call
))
2484 switch (gimple_call_internal_fn (call
))
2486 /* Treat these internal calls like ECF_PURE for aliasing,
2487 they don't write to any memory the program should care about.
2488 They have important other side-effects, and read memory,
2489 so can't be ECF_NOVOPS. */
2490 case IFN_UBSAN_NULL
:
2491 case IFN_UBSAN_BOUNDS
:
2492 case IFN_UBSAN_VPTR
:
2493 case IFN_UBSAN_OBJECT_SIZE
:
2495 case IFN_ASAN_CHECK
:
2501 base
= ao_ref_base (ref
);
2505 if (TREE_CODE (base
) == SSA_NAME
2506 || CONSTANT_CLASS_P (base
))
2509 /* A call that is not without side-effects might involve volatile
2510 accesses and thus conflicts with all other volatile accesses. */
2511 if (ref
->volatile_p
)
2514 /* If the reference is based on a decl that is not aliased the call
2515 cannot possibly clobber it. */
2517 && !may_be_aliased (base
)
2518 /* But local non-readonly statics can be modified through recursion
2519 or the call may implement a threading barrier which we must
2520 treat as may-def. */
2521 && (TREE_READONLY (base
)
2522 || !is_global_var (base
)))
2525 /* If the reference is based on a pointer that points to memory
2526 that may not be written to then the call cannot possibly clobber it. */
2527 if ((TREE_CODE (base
) == MEM_REF
2528 || TREE_CODE (base
) == TARGET_MEM_REF
)
2529 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
2530 && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base
, 0)))
2533 callee
= gimple_call_fndecl (call
);
2535 /* Handle those builtin functions explicitly that do not act as
2536 escape points. See tree-ssa-structalias.c:find_func_aliases
2537 for the list of builtins we might need to handle here. */
2538 if (callee
!= NULL_TREE
2539 && gimple_call_builtin_p (call
, BUILT_IN_NORMAL
))
2540 switch (DECL_FUNCTION_CODE (callee
))
2542 /* All the following functions clobber memory pointed to by
2543 their first argument. */
2544 case BUILT_IN_STRCPY
:
2545 case BUILT_IN_STRNCPY
:
2546 case BUILT_IN_MEMCPY
:
2547 case BUILT_IN_MEMMOVE
:
2548 case BUILT_IN_MEMPCPY
:
2549 case BUILT_IN_STPCPY
:
2550 case BUILT_IN_STPNCPY
:
2551 case BUILT_IN_STRCAT
:
2552 case BUILT_IN_STRNCAT
:
2553 case BUILT_IN_MEMSET
:
2554 case BUILT_IN_TM_MEMSET
:
2555 CASE_BUILT_IN_TM_STORE (1):
2556 CASE_BUILT_IN_TM_STORE (2):
2557 CASE_BUILT_IN_TM_STORE (4):
2558 CASE_BUILT_IN_TM_STORE (8):
2559 CASE_BUILT_IN_TM_STORE (FLOAT
):
2560 CASE_BUILT_IN_TM_STORE (DOUBLE
):
2561 CASE_BUILT_IN_TM_STORE (LDOUBLE
):
2562 CASE_BUILT_IN_TM_STORE (M64
):
2563 CASE_BUILT_IN_TM_STORE (M128
):
2564 CASE_BUILT_IN_TM_STORE (M256
):
2565 case BUILT_IN_TM_MEMCPY
:
2566 case BUILT_IN_TM_MEMMOVE
:
2569 tree size
= NULL_TREE
;
2570 /* Don't pass in size for strncat, as the maximum size
2571 is strlen (dest) + n + 1 instead of n, resp.
2572 n + 1 at dest + strlen (dest), but strlen (dest) isn't
2574 if (gimple_call_num_args (call
) == 3
2575 && DECL_FUNCTION_CODE (callee
) != BUILT_IN_STRNCAT
)
2576 size
= gimple_call_arg (call
, 2);
2577 ao_ref_init_from_ptr_and_size (&dref
,
2578 gimple_call_arg (call
, 0),
2580 return refs_may_alias_p_1 (&dref
, ref
, false);
2582 case BUILT_IN_STRCPY_CHK
:
2583 case BUILT_IN_STRNCPY_CHK
:
2584 case BUILT_IN_MEMCPY_CHK
:
2585 case BUILT_IN_MEMMOVE_CHK
:
2586 case BUILT_IN_MEMPCPY_CHK
:
2587 case BUILT_IN_STPCPY_CHK
:
2588 case BUILT_IN_STPNCPY_CHK
:
2589 case BUILT_IN_STRCAT_CHK
:
2590 case BUILT_IN_STRNCAT_CHK
:
2591 case BUILT_IN_MEMSET_CHK
:
2594 tree size
= NULL_TREE
;
2595 /* Don't pass in size for __strncat_chk, as the maximum size
2596 is strlen (dest) + n + 1 instead of n, resp.
2597 n + 1 at dest + strlen (dest), but strlen (dest) isn't
2599 if (gimple_call_num_args (call
) == 4
2600 && DECL_FUNCTION_CODE (callee
) != BUILT_IN_STRNCAT_CHK
)
2601 size
= gimple_call_arg (call
, 2);
2602 ao_ref_init_from_ptr_and_size (&dref
,
2603 gimple_call_arg (call
, 0),
2605 return refs_may_alias_p_1 (&dref
, ref
, false);
2607 case BUILT_IN_BCOPY
:
2610 tree size
= gimple_call_arg (call
, 2);
2611 ao_ref_init_from_ptr_and_size (&dref
,
2612 gimple_call_arg (call
, 1),
2614 return refs_may_alias_p_1 (&dref
, ref
, false);
2616 /* Allocating memory does not have any side-effects apart from
2617 being the definition point for the pointer. */
2618 case BUILT_IN_MALLOC
:
2619 case BUILT_IN_ALIGNED_ALLOC
:
2620 case BUILT_IN_CALLOC
:
2621 case BUILT_IN_STRDUP
:
2622 case BUILT_IN_STRNDUP
:
2623 /* Unix98 specifies that errno is set on allocation failure. */
2625 && targetm
.ref_may_alias_errno (ref
))
2628 case BUILT_IN_STACK_SAVE
:
2629 CASE_BUILT_IN_ALLOCA
:
2630 case BUILT_IN_ASSUME_ALIGNED
:
2632 /* But posix_memalign stores a pointer into the memory pointed to
2633 by its first argument. */
2634 case BUILT_IN_POSIX_MEMALIGN
:
2636 tree ptrptr
= gimple_call_arg (call
, 0);
2638 ao_ref_init_from_ptr_and_size (&dref
, ptrptr
,
2639 TYPE_SIZE_UNIT (ptr_type_node
));
2640 return (refs_may_alias_p_1 (&dref
, ref
, false)
2642 && targetm
.ref_may_alias_errno (ref
)));
2644 /* Freeing memory kills the pointed-to memory. More importantly
2645 the call has to serve as a barrier for moving loads and stores
2648 case BUILT_IN_VA_END
:
2650 tree ptr
= gimple_call_arg (call
, 0);
2651 return ptr_deref_may_alias_ref_p_1 (ptr
, ref
);
2653 /* Realloc serves both as allocation point and deallocation point. */
2654 case BUILT_IN_REALLOC
:
2656 tree ptr
= gimple_call_arg (call
, 0);
2657 /* Unix98 specifies that errno is set on allocation failure. */
2658 return ((flag_errno_math
2659 && targetm
.ref_may_alias_errno (ref
))
2660 || ptr_deref_may_alias_ref_p_1 (ptr
, ref
));
2662 case BUILT_IN_GAMMA_R
:
2663 case BUILT_IN_GAMMAF_R
:
2664 case BUILT_IN_GAMMAL_R
:
2665 case BUILT_IN_LGAMMA_R
:
2666 case BUILT_IN_LGAMMAF_R
:
2667 case BUILT_IN_LGAMMAL_R
:
2669 tree out
= gimple_call_arg (call
, 1);
2670 if (ptr_deref_may_alias_ref_p_1 (out
, ref
))
2672 if (flag_errno_math
)
2676 case BUILT_IN_FREXP
:
2677 case BUILT_IN_FREXPF
:
2678 case BUILT_IN_FREXPL
:
2680 case BUILT_IN_MODFF
:
2681 case BUILT_IN_MODFL
:
2683 tree out
= gimple_call_arg (call
, 1);
2684 return ptr_deref_may_alias_ref_p_1 (out
, ref
);
2686 case BUILT_IN_REMQUO
:
2687 case BUILT_IN_REMQUOF
:
2688 case BUILT_IN_REMQUOL
:
2690 tree out
= gimple_call_arg (call
, 2);
2691 if (ptr_deref_may_alias_ref_p_1 (out
, ref
))
2693 if (flag_errno_math
)
2697 case BUILT_IN_SINCOS
:
2698 case BUILT_IN_SINCOSF
:
2699 case BUILT_IN_SINCOSL
:
2701 tree sin
= gimple_call_arg (call
, 1);
2702 tree cos
= gimple_call_arg (call
, 2);
2703 return (ptr_deref_may_alias_ref_p_1 (sin
, ref
)
2704 || ptr_deref_may_alias_ref_p_1 (cos
, ref
));
2706 /* __sync_* builtins and some OpenMP builtins act as threading
2708 #undef DEF_SYNC_BUILTIN
2709 #define DEF_SYNC_BUILTIN(ENUM, NAME, TYPE, ATTRS) case ENUM:
2710 #include "sync-builtins.def"
2711 #undef DEF_SYNC_BUILTIN
2712 case BUILT_IN_GOMP_ATOMIC_START
:
2713 case BUILT_IN_GOMP_ATOMIC_END
:
2714 case BUILT_IN_GOMP_BARRIER
:
2715 case BUILT_IN_GOMP_BARRIER_CANCEL
:
2716 case BUILT_IN_GOMP_TASKWAIT
:
2717 case BUILT_IN_GOMP_TASKGROUP_END
:
2718 case BUILT_IN_GOMP_CRITICAL_START
:
2719 case BUILT_IN_GOMP_CRITICAL_END
:
2720 case BUILT_IN_GOMP_CRITICAL_NAME_START
:
2721 case BUILT_IN_GOMP_CRITICAL_NAME_END
:
2722 case BUILT_IN_GOMP_LOOP_END
:
2723 case BUILT_IN_GOMP_LOOP_END_CANCEL
:
2724 case BUILT_IN_GOMP_ORDERED_START
:
2725 case BUILT_IN_GOMP_ORDERED_END
:
2726 case BUILT_IN_GOMP_SECTIONS_END
:
2727 case BUILT_IN_GOMP_SECTIONS_END_CANCEL
:
2728 case BUILT_IN_GOMP_SINGLE_COPY_START
:
2729 case BUILT_IN_GOMP_SINGLE_COPY_END
:
2732 /* Fallthru to general call handling. */;
2735 /* Check if base is a global static variable that is not written
2737 if (callee
!= NULL_TREE
&& VAR_P (base
) && TREE_STATIC (base
))
2739 struct cgraph_node
*node
= cgraph_node::get (callee
);
2743 && (not_written
= ipa_reference_get_not_written_global (node
))
2744 && bitmap_bit_p (not_written
, ipa_reference_var_uid (base
)))
2748 /* Check if the base variable is call-clobbered. */
2750 return pt_solution_includes (gimple_call_clobber_set (call
), base
);
2751 else if ((TREE_CODE (base
) == MEM_REF
2752 || TREE_CODE (base
) == TARGET_MEM_REF
)
2753 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
)
2755 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (TREE_OPERAND (base
, 0));
2759 return pt_solutions_intersect (gimple_call_clobber_set (call
), &pi
->pt
);
2765 /* If the call in statement CALL may clobber the memory reference REF
2766 return true, otherwise return false. */
2769 call_may_clobber_ref_p (gcall
*call
, tree ref
)
2773 ao_ref_init (&r
, ref
);
2774 res
= call_may_clobber_ref_p_1 (call
, &r
);
2776 ++alias_stats
.call_may_clobber_ref_p_may_alias
;
2778 ++alias_stats
.call_may_clobber_ref_p_no_alias
;
2783 /* If the statement STMT may clobber the memory reference REF return true,
2784 otherwise return false. */
2787 stmt_may_clobber_ref_p_1 (gimple
*stmt
, ao_ref
*ref
, bool tbaa_p
)
2789 if (is_gimple_call (stmt
))
2791 tree lhs
= gimple_call_lhs (stmt
);
2793 && TREE_CODE (lhs
) != SSA_NAME
)
2796 ao_ref_init (&r
, lhs
);
2797 if (refs_may_alias_p_1 (ref
, &r
, tbaa_p
))
2801 return call_may_clobber_ref_p_1 (as_a
<gcall
*> (stmt
), ref
);
2803 else if (gimple_assign_single_p (stmt
))
2805 tree lhs
= gimple_assign_lhs (stmt
);
2806 if (TREE_CODE (lhs
) != SSA_NAME
)
2809 ao_ref_init (&r
, lhs
);
2810 return refs_may_alias_p_1 (ref
, &r
, tbaa_p
);
2813 else if (gimple_code (stmt
) == GIMPLE_ASM
)
2820 stmt_may_clobber_ref_p (gimple
*stmt
, tree ref
, bool tbaa_p
)
2823 ao_ref_init (&r
, ref
);
2824 return stmt_may_clobber_ref_p_1 (stmt
, &r
, tbaa_p
);
2827 /* Return true if store1 and store2 described by corresponding tuples
2828 <BASE, OFFSET, SIZE, MAX_SIZE> have the same size and store to the same
2832 same_addr_size_stores_p (tree base1
, poly_int64 offset1
, poly_int64 size1
,
2833 poly_int64 max_size1
,
2834 tree base2
, poly_int64 offset2
, poly_int64 size2
,
2835 poly_int64 max_size2
)
2837 /* Offsets need to be 0. */
2838 if (maybe_ne (offset1
, 0)
2839 || maybe_ne (offset2
, 0))
2842 bool base1_obj_p
= SSA_VAR_P (base1
);
2843 bool base2_obj_p
= SSA_VAR_P (base2
);
2845 /* We need one object. */
2846 if (base1_obj_p
== base2_obj_p
)
2848 tree obj
= base1_obj_p
? base1
: base2
;
2850 /* And we need one MEM_REF. */
2851 bool base1_memref_p
= TREE_CODE (base1
) == MEM_REF
;
2852 bool base2_memref_p
= TREE_CODE (base2
) == MEM_REF
;
2853 if (base1_memref_p
== base2_memref_p
)
2855 tree memref
= base1_memref_p
? base1
: base2
;
2857 /* Sizes need to be valid. */
2858 if (!known_size_p (max_size1
)
2859 || !known_size_p (max_size2
)
2860 || !known_size_p (size1
)
2861 || !known_size_p (size2
))
2864 /* Max_size needs to match size. */
2865 if (maybe_ne (max_size1
, size1
)
2866 || maybe_ne (max_size2
, size2
))
2869 /* Sizes need to match. */
2870 if (maybe_ne (size1
, size2
))
2874 /* Check that memref is a store to pointer with singleton points-to info. */
2875 if (!integer_zerop (TREE_OPERAND (memref
, 1)))
2877 tree ptr
= TREE_OPERAND (memref
, 0);
2878 if (TREE_CODE (ptr
) != SSA_NAME
)
2880 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (ptr
);
2881 unsigned int pt_uid
;
2883 || !pt_solution_singleton_or_null_p (&pi
->pt
, &pt_uid
))
2886 /* Be conservative with non-call exceptions when the address might
2888 if (cfun
->can_throw_non_call_exceptions
&& pi
->pt
.null
)
2891 /* Check that ptr points relative to obj. */
2892 unsigned int obj_uid
= DECL_PT_UID (obj
);
2893 if (obj_uid
!= pt_uid
)
2896 /* Check that the object size is the same as the store size. That ensures us
2897 that ptr points to the start of obj. */
2898 return (DECL_SIZE (obj
)
2899 && poly_int_tree_p (DECL_SIZE (obj
))
2900 && known_eq (wi::to_poly_offset (DECL_SIZE (obj
)), size1
));
2903 /* If STMT kills the memory reference REF return true, otherwise
2907 stmt_kills_ref_p (gimple
*stmt
, ao_ref
*ref
)
2909 if (!ao_ref_base (ref
))
2912 if (gimple_has_lhs (stmt
)
2913 && TREE_CODE (gimple_get_lhs (stmt
)) != SSA_NAME
2914 /* The assignment is not necessarily carried out if it can throw
2915 and we can catch it in the current function where we could inspect
2917 ??? We only need to care about the RHS throwing. For aggregate
2918 assignments or similar calls and non-call exceptions the LHS
2919 might throw as well. */
2920 && !stmt_can_throw_internal (cfun
, stmt
))
2922 tree lhs
= gimple_get_lhs (stmt
);
2923 /* If LHS is literally a base of the access we are done. */
2926 tree base
= ref
->ref
;
2927 tree innermost_dropped_array_ref
= NULL_TREE
;
2928 if (handled_component_p (base
))
2930 tree saved_lhs0
= NULL_TREE
;
2931 if (handled_component_p (lhs
))
2933 saved_lhs0
= TREE_OPERAND (lhs
, 0);
2934 TREE_OPERAND (lhs
, 0) = integer_zero_node
;
2938 /* Just compare the outermost handled component, if
2939 they are equal we have found a possible common
2941 tree saved_base0
= TREE_OPERAND (base
, 0);
2942 TREE_OPERAND (base
, 0) = integer_zero_node
;
2943 bool res
= operand_equal_p (lhs
, base
, 0);
2944 TREE_OPERAND (base
, 0) = saved_base0
;
2947 /* Remember if we drop an array-ref that we need to
2948 double-check not being at struct end. */
2949 if (TREE_CODE (base
) == ARRAY_REF
2950 || TREE_CODE (base
) == ARRAY_RANGE_REF
)
2951 innermost_dropped_array_ref
= base
;
2952 /* Otherwise drop handled components of the access. */
2955 while (handled_component_p (base
));
2957 TREE_OPERAND (lhs
, 0) = saved_lhs0
;
2959 /* Finally check if the lhs has the same address and size as the
2960 base candidate of the access. Watch out if we have dropped
2961 an array-ref that was at struct end, this means ref->ref may
2962 be outside of the TYPE_SIZE of its base. */
2963 if ((! innermost_dropped_array_ref
2964 || ! array_at_struct_end_p (innermost_dropped_array_ref
))
2966 || (((TYPE_SIZE (TREE_TYPE (lhs
))
2967 == TYPE_SIZE (TREE_TYPE (base
)))
2968 || (TYPE_SIZE (TREE_TYPE (lhs
))
2969 && TYPE_SIZE (TREE_TYPE (base
))
2970 && operand_equal_p (TYPE_SIZE (TREE_TYPE (lhs
)),
2971 TYPE_SIZE (TREE_TYPE (base
)),
2973 && operand_equal_p (lhs
, base
,
2975 | OEP_MATCH_SIDE_EFFECTS
))))
2979 /* Now look for non-literal equal bases with the restriction of
2980 handling constant offset and size. */
2981 /* For a must-alias check we need to be able to constrain
2982 the access properly. */
2983 if (!ref
->max_size_known_p ())
2985 poly_int64 size
, offset
, max_size
, ref_offset
= ref
->offset
;
2987 tree base
= get_ref_base_and_extent (lhs
, &offset
, &size
, &max_size
,
2989 /* We can get MEM[symbol: sZ, index: D.8862_1] here,
2990 so base == ref->base does not always hold. */
2991 if (base
!= ref
->base
)
2993 /* Try using points-to info. */
2994 if (same_addr_size_stores_p (base
, offset
, size
, max_size
, ref
->base
,
2995 ref
->offset
, ref
->size
, ref
->max_size
))
2998 /* If both base and ref->base are MEM_REFs, only compare the
2999 first operand, and if the second operand isn't equal constant,
3000 try to add the offsets into offset and ref_offset. */
3001 if (TREE_CODE (base
) == MEM_REF
&& TREE_CODE (ref
->base
) == MEM_REF
3002 && TREE_OPERAND (base
, 0) == TREE_OPERAND (ref
->base
, 0))
3004 if (!tree_int_cst_equal (TREE_OPERAND (base
, 1),
3005 TREE_OPERAND (ref
->base
, 1)))
3007 poly_offset_int off1
= mem_ref_offset (base
);
3008 off1
<<= LOG2_BITS_PER_UNIT
;
3010 poly_offset_int off2
= mem_ref_offset (ref
->base
);
3011 off2
<<= LOG2_BITS_PER_UNIT
;
3013 if (!off1
.to_shwi (&offset
) || !off2
.to_shwi (&ref_offset
))
3020 /* For a must-alias check we need to be able to constrain
3021 the access properly. */
3022 if (known_eq (size
, max_size
)
3023 && known_subrange_p (ref_offset
, ref
->max_size
, offset
, size
))
3027 if (is_gimple_call (stmt
))
3029 tree callee
= gimple_call_fndecl (stmt
);
3030 if (callee
!= NULL_TREE
3031 && gimple_call_builtin_p (stmt
, BUILT_IN_NORMAL
))
3032 switch (DECL_FUNCTION_CODE (callee
))
3036 tree ptr
= gimple_call_arg (stmt
, 0);
3037 tree base
= ao_ref_base (ref
);
3038 if (base
&& TREE_CODE (base
) == MEM_REF
3039 && TREE_OPERAND (base
, 0) == ptr
)
3044 case BUILT_IN_MEMCPY
:
3045 case BUILT_IN_MEMPCPY
:
3046 case BUILT_IN_MEMMOVE
:
3047 case BUILT_IN_MEMSET
:
3048 case BUILT_IN_MEMCPY_CHK
:
3049 case BUILT_IN_MEMPCPY_CHK
:
3050 case BUILT_IN_MEMMOVE_CHK
:
3051 case BUILT_IN_MEMSET_CHK
:
3052 case BUILT_IN_STRNCPY
:
3053 case BUILT_IN_STPNCPY
:
3054 case BUILT_IN_CALLOC
:
3056 /* For a must-alias check we need to be able to constrain
3057 the access properly. */
3058 if (!ref
->max_size_known_p ())
3063 /* In execution order a calloc call will never kill
3064 anything. However, DSE will (ab)use this interface
3065 to ask if a calloc call writes the same memory locations
3066 as a later assignment, memset, etc. So handle calloc
3067 in the expected way. */
3068 if (DECL_FUNCTION_CODE (callee
) == BUILT_IN_CALLOC
)
3070 tree arg0
= gimple_call_arg (stmt
, 0);
3071 tree arg1
= gimple_call_arg (stmt
, 1);
3072 if (TREE_CODE (arg0
) != INTEGER_CST
3073 || TREE_CODE (arg1
) != INTEGER_CST
)
3076 dest
= gimple_call_lhs (stmt
);
3077 len
= fold_build2 (MULT_EXPR
, TREE_TYPE (arg0
), arg0
, arg1
);
3081 dest
= gimple_call_arg (stmt
, 0);
3082 len
= gimple_call_arg (stmt
, 2);
3084 if (!poly_int_tree_p (len
))
3086 tree rbase
= ref
->base
;
3087 poly_offset_int roffset
= ref
->offset
;
3089 ao_ref_init_from_ptr_and_size (&dref
, dest
, len
);
3090 tree base
= ao_ref_base (&dref
);
3091 poly_offset_int offset
= dref
.offset
;
3092 if (!base
|| !known_size_p (dref
.size
))
3094 if (TREE_CODE (base
) == MEM_REF
)
3096 if (TREE_CODE (rbase
) != MEM_REF
)
3098 // Compare pointers.
3099 offset
+= mem_ref_offset (base
) << LOG2_BITS_PER_UNIT
;
3100 roffset
+= mem_ref_offset (rbase
) << LOG2_BITS_PER_UNIT
;
3101 base
= TREE_OPERAND (base
, 0);
3102 rbase
= TREE_OPERAND (rbase
, 0);
3105 && known_subrange_p (roffset
, ref
->max_size
, offset
,
3106 wi::to_poly_offset (len
)
3107 << LOG2_BITS_PER_UNIT
))
3112 case BUILT_IN_VA_END
:
3114 tree ptr
= gimple_call_arg (stmt
, 0);
3115 if (TREE_CODE (ptr
) == ADDR_EXPR
)
3117 tree base
= ao_ref_base (ref
);
3118 if (TREE_OPERAND (ptr
, 0) == base
)
3131 stmt_kills_ref_p (gimple
*stmt
, tree ref
)
3134 ao_ref_init (&r
, ref
);
3135 return stmt_kills_ref_p (stmt
, &r
);
3139 /* Walk the virtual use-def chain of VUSE until hitting the virtual operand
3140 TARGET or a statement clobbering the memory reference REF in which
3141 case false is returned. The walk starts with VUSE, one argument of PHI. */
3144 maybe_skip_until (gimple
*phi
, tree
&target
, basic_block target_bb
,
3145 ao_ref
*ref
, tree vuse
, bool tbaa_p
, unsigned int &limit
,
3146 bitmap
*visited
, bool abort_on_visited
,
3147 void *(*translate
)(ao_ref
*, tree
, void *, bool *),
3150 basic_block bb
= gimple_bb (phi
);
3153 *visited
= BITMAP_ALLOC (NULL
);
3155 bitmap_set_bit (*visited
, SSA_NAME_VERSION (PHI_RESULT (phi
)));
3157 /* Walk until we hit the target. */
3158 while (vuse
!= target
)
3160 gimple
*def_stmt
= SSA_NAME_DEF_STMT (vuse
);
3161 /* If we are searching for the target VUSE by walking up to
3162 TARGET_BB dominating the original PHI we are finished once
3163 we reach a default def or a definition in a block dominating
3164 that block. Update TARGET and return. */
3166 && (gimple_nop_p (def_stmt
)
3167 || dominated_by_p (CDI_DOMINATORS
,
3168 target_bb
, gimple_bb (def_stmt
))))
3174 /* Recurse for PHI nodes. */
3175 if (gimple_code (def_stmt
) == GIMPLE_PHI
)
3177 /* An already visited PHI node ends the walk successfully. */
3178 if (bitmap_bit_p (*visited
, SSA_NAME_VERSION (PHI_RESULT (def_stmt
))))
3179 return !abort_on_visited
;
3180 vuse
= get_continuation_for_phi (def_stmt
, ref
, tbaa_p
, limit
,
3181 visited
, abort_on_visited
,
3187 else if (gimple_nop_p (def_stmt
))
3191 /* A clobbering statement or the end of the IL ends it failing. */
3192 if ((int)limit
<= 0)
3195 if (stmt_may_clobber_ref_p_1 (def_stmt
, ref
, tbaa_p
))
3197 bool disambiguate_only
= true;
3199 && (*translate
) (ref
, vuse
, data
, &disambiguate_only
) == NULL
)
3205 /* If we reach a new basic-block see if we already skipped it
3206 in a previous walk that ended successfully. */
3207 if (gimple_bb (def_stmt
) != bb
)
3209 if (!bitmap_set_bit (*visited
, SSA_NAME_VERSION (vuse
)))
3210 return !abort_on_visited
;
3211 bb
= gimple_bb (def_stmt
);
3213 vuse
= gimple_vuse (def_stmt
);
3219 /* Starting from a PHI node for the virtual operand of the memory reference
3220 REF find a continuation virtual operand that allows to continue walking
3221 statements dominating PHI skipping only statements that cannot possibly
3222 clobber REF. Decrements LIMIT for each alias disambiguation done
3223 and aborts the walk, returning NULL_TREE if it reaches zero.
3224 Returns NULL_TREE if no suitable virtual operand can be found. */
3227 get_continuation_for_phi (gimple
*phi
, ao_ref
*ref
, bool tbaa_p
,
3228 unsigned int &limit
, bitmap
*visited
,
3229 bool abort_on_visited
,
3230 void *(*translate
)(ao_ref
*, tree
, void *, bool *),
3233 unsigned nargs
= gimple_phi_num_args (phi
);
3235 /* Through a single-argument PHI we can simply look through. */
3237 return PHI_ARG_DEF (phi
, 0);
3239 /* For two or more arguments try to pairwise skip non-aliasing code
3240 until we hit the phi argument definition that dominates the other one. */
3241 basic_block phi_bb
= gimple_bb (phi
);
3245 /* Find a candidate for the virtual operand which definition
3246 dominates those of all others. */
3247 /* First look if any of the args themselves satisfy this. */
3248 for (i
= 0; i
< nargs
; ++i
)
3250 arg0
= PHI_ARG_DEF (phi
, i
);
3251 if (SSA_NAME_IS_DEFAULT_DEF (arg0
))
3253 basic_block def_bb
= gimple_bb (SSA_NAME_DEF_STMT (arg0
));
3254 if (def_bb
!= phi_bb
3255 && dominated_by_p (CDI_DOMINATORS
, phi_bb
, def_bb
))
3259 /* If not, look if we can reach such candidate by walking defs
3260 until we hit the immediate dominator. maybe_skip_until will
3262 basic_block dom
= get_immediate_dominator (CDI_DOMINATORS
, phi_bb
);
3264 /* Then check against the (to be) found candidate. */
3265 for (i
= 0; i
< nargs
; ++i
)
3267 arg1
= PHI_ARG_DEF (phi
, i
);
3270 else if (! maybe_skip_until (phi
, arg0
, dom
, ref
, arg1
, tbaa_p
,
3273 /* Do not translate when walking over
3277 gimple_bb (SSA_NAME_DEF_STMT (arg1
)),
3279 ? NULL
: translate
, data
))
3286 /* Based on the memory reference REF and its virtual use VUSE call
3287 WALKER for each virtual use that is equivalent to VUSE, including VUSE
3288 itself. That is, for each virtual use for which its defining statement
3289 does not clobber REF.
3291 WALKER is called with REF, the current virtual use and DATA. If
3292 WALKER returns non-NULL the walk stops and its result is returned.
3293 At the end of a non-successful walk NULL is returned.
3295 TRANSLATE if non-NULL is called with a pointer to REF, the virtual
3296 use which definition is a statement that may clobber REF and DATA.
3297 If TRANSLATE returns (void *)-1 the walk stops and NULL is returned.
3298 If TRANSLATE returns non-NULL the walk stops and its result is returned.
3299 If TRANSLATE returns NULL the walk continues and TRANSLATE is supposed
3300 to adjust REF and *DATA to make that valid.
3302 VALUEIZE if non-NULL is called with the next VUSE that is considered
3303 and return value is substituted for that. This can be used to
3304 implement optimistic value-numbering for example. Note that the
3305 VUSE argument is assumed to be valueized already.
3307 LIMIT specifies the number of alias queries we are allowed to do,
3308 the walk stops when it reaches zero and NULL is returned. LIMIT
3309 is decremented by the number of alias queries (plus adjustments
3310 done by the callbacks) upon return.
3312 TODO: Cache the vector of equivalent vuses per ref, vuse pair. */
3315 walk_non_aliased_vuses (ao_ref
*ref
, tree vuse
, bool tbaa_p
,
3316 void *(*walker
)(ao_ref
*, tree
, void *),
3317 void *(*translate
)(ao_ref
*, tree
, void *, bool *),
3318 tree (*valueize
)(tree
),
3319 unsigned &limit
, void *data
)
3321 bitmap visited
= NULL
;
3323 bool translated
= false;
3325 timevar_push (TV_ALIAS_STMT_WALK
);
3331 /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */
3332 res
= (*walker
) (ref
, vuse
, data
);
3334 if (res
== (void *)-1)
3339 /* Lookup succeeded. */
3340 else if (res
!= NULL
)
3345 vuse
= valueize (vuse
);
3352 def_stmt
= SSA_NAME_DEF_STMT (vuse
);
3353 if (gimple_nop_p (def_stmt
))
3355 else if (gimple_code (def_stmt
) == GIMPLE_PHI
)
3356 vuse
= get_continuation_for_phi (def_stmt
, ref
, tbaa_p
, limit
,
3357 &visited
, translated
, translate
, data
);
3360 if ((int)limit
<= 0)
3366 if (stmt_may_clobber_ref_p_1 (def_stmt
, ref
, tbaa_p
))
3370 bool disambiguate_only
= false;
3371 res
= (*translate
) (ref
, vuse
, data
, &disambiguate_only
);
3372 /* Failed lookup and translation. */
3373 if (res
== (void *)-1)
3378 /* Lookup succeeded. */
3379 else if (res
!= NULL
)
3381 /* Translation succeeded, continue walking. */
3382 translated
= translated
|| !disambiguate_only
;
3384 vuse
= gimple_vuse (def_stmt
);
3390 BITMAP_FREE (visited
);
3392 timevar_pop (TV_ALIAS_STMT_WALK
);
3398 /* Based on the memory reference REF call WALKER for each vdef which
3399 defining statement may clobber REF, starting with VDEF. If REF
3400 is NULL_TREE, each defining statement is visited.
3402 WALKER is called with REF, the current vdef and DATA. If WALKER
3403 returns true the walk is stopped, otherwise it continues.
3405 If function entry is reached, FUNCTION_ENTRY_REACHED is set to true.
3406 The pointer may be NULL and then we do not track this information.
3408 At PHI nodes walk_aliased_vdefs forks into one walk for reach
3409 PHI argument (but only one walk continues on merge points), the
3410 return value is true if any of the walks was successful.
3412 The function returns the number of statements walked or -1 if
3413 LIMIT stmts were walked and the walk was aborted at this point.
3414 If LIMIT is zero the walk is not aborted. */
3417 walk_aliased_vdefs_1 (ao_ref
*ref
, tree vdef
,
3418 bool (*walker
)(ao_ref
*, tree
, void *), void *data
,
3419 bitmap
*visited
, unsigned int cnt
,
3420 bool *function_entry_reached
, unsigned limit
)
3424 gimple
*def_stmt
= SSA_NAME_DEF_STMT (vdef
);
3427 && !bitmap_set_bit (*visited
, SSA_NAME_VERSION (vdef
)))
3430 if (gimple_nop_p (def_stmt
))
3432 if (function_entry_reached
)
3433 *function_entry_reached
= true;
3436 else if (gimple_code (def_stmt
) == GIMPLE_PHI
)
3440 *visited
= BITMAP_ALLOC (NULL
);
3441 for (i
= 0; i
< gimple_phi_num_args (def_stmt
); ++i
)
3443 int res
= walk_aliased_vdefs_1 (ref
,
3444 gimple_phi_arg_def (def_stmt
, i
),
3445 walker
, data
, visited
, cnt
,
3446 function_entry_reached
, limit
);
3454 /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */
3459 || stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
3460 && (*walker
) (ref
, vdef
, data
))
3463 vdef
= gimple_vuse (def_stmt
);
3469 walk_aliased_vdefs (ao_ref
*ref
, tree vdef
,
3470 bool (*walker
)(ao_ref
*, tree
, void *), void *data
,
3472 bool *function_entry_reached
, unsigned int limit
)
3474 bitmap local_visited
= NULL
;
3477 timevar_push (TV_ALIAS_STMT_WALK
);
3479 if (function_entry_reached
)
3480 *function_entry_reached
= false;
3482 ret
= walk_aliased_vdefs_1 (ref
, vdef
, walker
, data
,
3483 visited
? visited
: &local_visited
, 0,
3484 function_entry_reached
, limit
);
3486 BITMAP_FREE (local_visited
);
3488 timevar_pop (TV_ALIAS_STMT_WALK
);