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 /* Try to disambiguate REF1 and REF2 under the assumption that MATCH1 and
1132 MATCH2 either point to the same address or are disjoint.
1133 MATCH1 and MATCH2 are assumed to be ref in the access path of REF1 and REF2
1134 respectively or NULL in the case we established equivalence of bases.
1136 This test works by matching the initial segment of the access path
1137 and does not rely on TBAA thus is safe for !flag_strict_aliasing if
1138 match was determined without use of TBAA oracle.
1140 Return 1 if we can determine that component references REF1 and REF2,
1141 that are within a common DECL, cannot overlap.
1143 Return 0 if paths are same and thus there is nothing to disambiguate more
1144 (i.e. there is must alias assuming there is must alias between MATCH1 and
1147 Return -1 if we can not determine 0 or 1 - this happens when we met
1148 non-matching types was met in the path.
1149 In this case it may make sense to continue by other disambiguation
1153 nonoverlapping_component_refs_since_match_p (tree match1
, tree ref1
,
1154 tree match2
, tree ref2
)
1156 /* Early return if there are no references to match, we do not need
1157 to walk the access paths.
1159 Do not consider this as may-alias for stats - it is more useful
1160 to have information how many disambiguations happened provided that
1161 the query was meaningful. */
1163 if (match1
== ref1
|| !handled_component_p (ref1
)
1164 || match2
== ref2
|| !handled_component_p (ref2
))
1167 auto_vec
<tree
, 16> component_refs1
;
1168 auto_vec
<tree
, 16> component_refs2
;
1170 /* Create the stack of handled components for REF1. */
1171 while (handled_component_p (ref1
) && ref1
!= match1
)
1173 if (TREE_CODE (ref1
) == VIEW_CONVERT_EXPR
1174 || TREE_CODE (ref1
) == BIT_FIELD_REF
)
1175 component_refs1
.truncate (0);
1177 component_refs1
.safe_push (ref1
);
1178 ref1
= TREE_OPERAND (ref1
, 0);
1180 if (TREE_CODE (ref1
) == MEM_REF
&& ref1
!= match1
)
1182 if (!integer_zerop (TREE_OPERAND (ref1
, 1)))
1184 ++alias_stats
.nonoverlapping_component_refs_since_match_p_may_alias
;
1188 /* TODO: Handle TARGET_MEM_REF later. */
1189 if (TREE_CODE (ref1
) == TARGET_MEM_REF
&& ref1
!= match1
)
1191 ++alias_stats
.nonoverlapping_component_refs_since_match_p_may_alias
;
1195 /* Create the stack of handled components for REF2. */
1196 while (handled_component_p (ref2
) && ref2
!= match2
)
1198 if (TREE_CODE (ref2
) == VIEW_CONVERT_EXPR
1199 || TREE_CODE (ref2
) == BIT_FIELD_REF
)
1200 component_refs2
.truncate (0);
1202 component_refs2
.safe_push (ref2
);
1203 ref2
= TREE_OPERAND (ref2
, 0);
1205 if (TREE_CODE (ref2
) == MEM_REF
&& ref2
!= match2
)
1207 if (!integer_zerop (TREE_OPERAND (ref2
, 1)))
1209 ++alias_stats
.nonoverlapping_component_refs_since_match_p_may_alias
;
1213 if (TREE_CODE (ref2
) == TARGET_MEM_REF
&& ref2
!= match2
)
1215 ++alias_stats
.nonoverlapping_component_refs_since_match_p_may_alias
;
1219 /* Pop the stacks in parallel and examine the COMPONENT_REFs of the same
1220 rank. This is sufficient because we start from the same DECL and you
1221 cannot reference several fields at a time with COMPONENT_REFs (unlike
1222 with ARRAY_RANGE_REFs for arrays) so you always need the same number
1223 of them to access a sub-component, unless you're in a union, in which
1224 case the return value will precisely be false. */
1229 if (component_refs1
.is_empty ())
1232 .nonoverlapping_component_refs_since_match_p_must_overlap
;
1235 ref1
= component_refs1
.pop ();
1237 while (!RECORD_OR_UNION_TYPE_P (TREE_TYPE (TREE_OPERAND (ref1
, 0))));
1241 if (component_refs2
.is_empty ())
1244 .nonoverlapping_component_refs_since_match_p_must_overlap
;
1247 ref2
= component_refs2
.pop ();
1249 while (!RECORD_OR_UNION_TYPE_P (TREE_TYPE (TREE_OPERAND (ref2
, 0))));
1251 /* Beware of BIT_FIELD_REF. */
1252 if (TREE_CODE (ref1
) != COMPONENT_REF
1253 || TREE_CODE (ref2
) != COMPONENT_REF
)
1256 .nonoverlapping_component_refs_since_match_p_may_alias
;
1260 tree field1
= TREE_OPERAND (ref1
, 1);
1261 tree field2
= TREE_OPERAND (ref2
, 1);
1263 /* ??? We cannot simply use the type of operand #0 of the refs here
1264 as the Fortran compiler smuggles type punning into COMPONENT_REFs
1265 for common blocks instead of using unions like everyone else. */
1266 tree type1
= DECL_CONTEXT (field1
);
1267 tree type2
= DECL_CONTEXT (field2
);
1269 /* We cannot disambiguate fields in a union or qualified union. */
1270 if (type1
!= type2
|| TREE_CODE (type1
) != RECORD_TYPE
)
1272 ++alias_stats
.nonoverlapping_component_refs_since_match_p_may_alias
;
1276 if (field1
!= field2
)
1278 /* A field and its representative need to be considered the
1280 if (DECL_BIT_FIELD_REPRESENTATIVE (field1
) == field2
1281 || DECL_BIT_FIELD_REPRESENTATIVE (field2
) == field1
)
1284 .nonoverlapping_component_refs_since_match_p_must_overlap
;
1287 /* Different fields of the same record type cannot overlap.
1288 ??? Bitfields can overlap at RTL level so punt on them. */
1289 if (DECL_BIT_FIELD (field1
) && DECL_BIT_FIELD (field2
))
1292 .nonoverlapping_component_refs_since_match_p_must_overlap
;
1295 ++alias_stats
.nonoverlapping_component_refs_since_match_p_no_alias
;
1300 ++alias_stats
.nonoverlapping_component_refs_since_match_p_must_overlap
;
1304 /* qsort compare function to sort FIELD_DECLs after their
1305 DECL_FIELD_CONTEXT TYPE_UID. */
1308 ncr_compar (const void *field1_
, const void *field2_
)
1310 const_tree field1
= *(const_tree
*) const_cast <void *>(field1_
);
1311 const_tree field2
= *(const_tree
*) const_cast <void *>(field2_
);
1312 unsigned int uid1
= TYPE_UID (DECL_FIELD_CONTEXT (field1
));
1313 unsigned int uid2
= TYPE_UID (DECL_FIELD_CONTEXT (field2
));
1316 else if (uid1
> uid2
)
1321 /* Return true if we can determine that the fields referenced cannot
1322 overlap for any pair of objects. This relies on TBAA. */
1325 nonoverlapping_component_refs_p (const_tree x
, const_tree y
)
1327 /* Early return if we have nothing to do.
1329 Do not consider this as may-alias for stats - it is more useful
1330 to have information how many disambiguations happened provided that
1331 the query was meaningful. */
1332 if (!flag_strict_aliasing
1334 || !handled_component_p (x
)
1335 || !handled_component_p (y
))
1338 auto_vec
<const_tree
, 16> fieldsx
;
1339 while (handled_component_p (x
))
1341 if (TREE_CODE (x
) == COMPONENT_REF
)
1343 tree field
= TREE_OPERAND (x
, 1);
1344 tree type
= DECL_FIELD_CONTEXT (field
);
1345 if (TREE_CODE (type
) == RECORD_TYPE
)
1346 fieldsx
.safe_push (field
);
1348 else if (TREE_CODE (x
) == VIEW_CONVERT_EXPR
1349 || TREE_CODE (x
) == BIT_FIELD_REF
)
1350 fieldsx
.truncate (0);
1351 x
= TREE_OPERAND (x
, 0);
1353 if (fieldsx
.length () == 0)
1355 auto_vec
<const_tree
, 16> fieldsy
;
1356 while (handled_component_p (y
))
1358 if (TREE_CODE (y
) == COMPONENT_REF
)
1360 tree field
= TREE_OPERAND (y
, 1);
1361 tree type
= DECL_FIELD_CONTEXT (field
);
1362 if (TREE_CODE (type
) == RECORD_TYPE
)
1363 fieldsy
.safe_push (TREE_OPERAND (y
, 1));
1365 else if (TREE_CODE (y
) == VIEW_CONVERT_EXPR
1366 || TREE_CODE (y
) == BIT_FIELD_REF
)
1367 fieldsy
.truncate (0);
1368 y
= TREE_OPERAND (y
, 0);
1370 if (fieldsy
.length () == 0)
1372 ++alias_stats
.nonoverlapping_component_refs_p_may_alias
;
1376 /* Most common case first. */
1377 if (fieldsx
.length () == 1
1378 && fieldsy
.length () == 1)
1380 if ((DECL_FIELD_CONTEXT (fieldsx
[0])
1381 == DECL_FIELD_CONTEXT (fieldsy
[0]))
1382 && fieldsx
[0] != fieldsy
[0]
1383 && !(DECL_BIT_FIELD (fieldsx
[0]) && DECL_BIT_FIELD (fieldsy
[0])))
1385 ++alias_stats
.nonoverlapping_component_refs_p_no_alias
;
1390 ++alias_stats
.nonoverlapping_component_refs_p_may_alias
;
1395 if (fieldsx
.length () == 2)
1397 if (ncr_compar (&fieldsx
[0], &fieldsx
[1]) == 1)
1398 std::swap (fieldsx
[0], fieldsx
[1]);
1401 fieldsx
.qsort (ncr_compar
);
1403 if (fieldsy
.length () == 2)
1405 if (ncr_compar (&fieldsy
[0], &fieldsy
[1]) == 1)
1406 std::swap (fieldsy
[0], fieldsy
[1]);
1409 fieldsy
.qsort (ncr_compar
);
1411 unsigned i
= 0, j
= 0;
1414 const_tree fieldx
= fieldsx
[i
];
1415 const_tree fieldy
= fieldsy
[j
];
1416 tree typex
= DECL_FIELD_CONTEXT (fieldx
);
1417 tree typey
= DECL_FIELD_CONTEXT (fieldy
);
1420 /* We're left with accessing different fields of a structure,
1421 no possible overlap. */
1422 if (fieldx
!= fieldy
)
1424 /* A field and its representative need to be considered the
1426 if (DECL_BIT_FIELD_REPRESENTATIVE (fieldx
) == fieldy
1427 || DECL_BIT_FIELD_REPRESENTATIVE (fieldy
) == fieldx
)
1429 /* Different fields of the same record type cannot overlap.
1430 ??? Bitfields can overlap at RTL level so punt on them. */
1431 else if (DECL_BIT_FIELD (fieldx
) && DECL_BIT_FIELD (fieldy
))
1435 ++alias_stats
.nonoverlapping_component_refs_p_no_alias
;
1440 if (TYPE_UID (typex
) < TYPE_UID (typey
))
1443 if (i
== fieldsx
.length ())
1449 if (j
== fieldsy
.length ())
1455 ++alias_stats
.nonoverlapping_component_refs_p_may_alias
;
1460 /* Return true if two memory references based on the variables BASE1
1461 and BASE2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and
1462 [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. REF1 and REF2
1463 if non-NULL are the complete memory reference trees. */
1466 decl_refs_may_alias_p (tree ref1
, tree base1
,
1467 poly_int64 offset1
, poly_int64 max_size1
,
1469 tree ref2
, tree base2
,
1470 poly_int64 offset2
, poly_int64 max_size2
,
1473 gcc_checking_assert (DECL_P (base1
) && DECL_P (base2
));
1475 /* If both references are based on different variables, they cannot alias. */
1476 if (compare_base_decls (base1
, base2
) == 0)
1479 /* If both references are based on the same variable, they cannot alias if
1480 the accesses do not overlap. */
1481 if (!ranges_maybe_overlap_p (offset1
, max_size1
, offset2
, max_size2
))
1484 /* If there is must alias, there is no use disambiguating further. */
1485 if (known_eq (size1
, max_size1
) && known_eq (size2
, max_size2
))
1488 /* For components with variable position, the above test isn't sufficient,
1489 so we disambiguate component references manually. */
1491 && handled_component_p (ref1
) && handled_component_p (ref2
)
1492 && nonoverlapping_component_refs_since_match_p (NULL
, ref1
,
1499 /* Return true if an indirect reference based on *PTR1 constrained
1500 to [OFFSET1, OFFSET1 + MAX_SIZE1) may alias a variable based on BASE2
1501 constrained to [OFFSET2, OFFSET2 + MAX_SIZE2). *PTR1 and BASE2 have
1502 the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1
1503 in which case they are computed on-demand. REF1 and REF2
1504 if non-NULL are the complete memory reference trees. */
1507 indirect_ref_may_alias_decl_p (tree ref1 ATTRIBUTE_UNUSED
, tree base1
,
1508 poly_int64 offset1
, poly_int64 max_size1
,
1510 alias_set_type ref1_alias_set
,
1511 alias_set_type base1_alias_set
,
1512 tree ref2 ATTRIBUTE_UNUSED
, tree base2
,
1513 poly_int64 offset2
, poly_int64 max_size2
,
1515 alias_set_type ref2_alias_set
,
1516 alias_set_type base2_alias_set
, bool tbaa_p
)
1519 tree ptrtype1
, dbase2
;
1521 gcc_checking_assert ((TREE_CODE (base1
) == MEM_REF
1522 || TREE_CODE (base1
) == TARGET_MEM_REF
)
1525 ptr1
= TREE_OPERAND (base1
, 0);
1526 poly_offset_int moff
= mem_ref_offset (base1
) << LOG2_BITS_PER_UNIT
;
1528 /* If only one reference is based on a variable, they cannot alias if
1529 the pointer access is beyond the extent of the variable access.
1530 (the pointer base cannot validly point to an offset less than zero
1532 ??? IVOPTs creates bases that do not honor this restriction,
1533 so do not apply this optimization for TARGET_MEM_REFs. */
1534 if (TREE_CODE (base1
) != TARGET_MEM_REF
1535 && !ranges_maybe_overlap_p (offset1
+ moff
, -1, offset2
, max_size2
))
1537 /* They also cannot alias if the pointer may not point to the decl. */
1538 if (!ptr_deref_may_alias_decl_p (ptr1
, base2
))
1541 /* Disambiguations that rely on strict aliasing rules follow. */
1542 if (!flag_strict_aliasing
|| !tbaa_p
)
1545 /* If the alias set for a pointer access is zero all bets are off. */
1546 if (base1_alias_set
== 0 || base2_alias_set
== 0)
1549 /* When we are trying to disambiguate an access with a pointer dereference
1550 as base versus one with a decl as base we can use both the size
1551 of the decl and its dynamic type for extra disambiguation.
1552 ??? We do not know anything about the dynamic type of the decl
1553 other than that its alias-set contains base2_alias_set as a subset
1554 which does not help us here. */
1555 /* As we know nothing useful about the dynamic type of the decl just
1556 use the usual conflict check rather than a subset test.
1557 ??? We could introduce -fvery-strict-aliasing when the language
1558 does not allow decls to have a dynamic type that differs from their
1559 static type. Then we can check
1560 !alias_set_subset_of (base1_alias_set, base2_alias_set) instead. */
1561 if (base1_alias_set
!= base2_alias_set
1562 && !alias_sets_conflict_p (base1_alias_set
, base2_alias_set
))
1565 ptrtype1
= TREE_TYPE (TREE_OPERAND (base1
, 1));
1567 /* If the size of the access relevant for TBAA through the pointer
1568 is bigger than the size of the decl we can't possibly access the
1569 decl via that pointer. */
1570 if (/* ??? This in turn may run afoul when a decl of type T which is
1571 a member of union type U is accessed through a pointer to
1572 type U and sizeof T is smaller than sizeof U. */
1573 TREE_CODE (TREE_TYPE (ptrtype1
)) != UNION_TYPE
1574 && TREE_CODE (TREE_TYPE (ptrtype1
)) != QUAL_UNION_TYPE
1575 && compare_sizes (DECL_SIZE (base2
),
1576 TYPE_SIZE (TREE_TYPE (ptrtype1
))) < 0)
1582 /* If the decl is accessed via a MEM_REF, reconstruct the base
1583 we can use for TBAA and an appropriately adjusted offset. */
1585 while (handled_component_p (dbase2
))
1586 dbase2
= TREE_OPERAND (dbase2
, 0);
1587 poly_int64 doffset1
= offset1
;
1588 poly_offset_int doffset2
= offset2
;
1589 if (TREE_CODE (dbase2
) == MEM_REF
1590 || TREE_CODE (dbase2
) == TARGET_MEM_REF
)
1592 doffset2
-= mem_ref_offset (dbase2
) << LOG2_BITS_PER_UNIT
;
1593 tree ptrtype2
= TREE_TYPE (TREE_OPERAND (dbase2
, 1));
1594 /* If second reference is view-converted, give up now. */
1595 if (same_type_for_tbaa (TREE_TYPE (dbase2
), TREE_TYPE (ptrtype2
)) != 1)
1599 /* If first reference is view-converted, give up now. */
1600 if (same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (ptrtype1
)) != 1)
1603 /* If both references are through the same type, they do not alias
1604 if the accesses do not overlap. This does extra disambiguation
1605 for mixed/pointer accesses but requires strict aliasing.
1606 For MEM_REFs we require that the component-ref offset we computed
1607 is relative to the start of the type which we ensure by
1608 comparing rvalue and access type and disregarding the constant
1611 But avoid treating variable length arrays as "objects", instead assume they
1612 can overlap by an exact multiple of their element size.
1613 See gcc.dg/torture/alias-2.c. */
1614 if (((TREE_CODE (base1
) != TARGET_MEM_REF
1615 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1616 && (TREE_CODE (dbase2
) != TARGET_MEM_REF
1617 || (!TMR_INDEX (dbase2
) && !TMR_INDEX2 (dbase2
))))
1618 && same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (dbase2
)) == 1
1619 && (TREE_CODE (TREE_TYPE (base1
)) != ARRAY_TYPE
1620 || (TYPE_SIZE (TREE_TYPE (base1
))
1621 && TREE_CODE (TYPE_SIZE (TREE_TYPE (base1
))) == INTEGER_CST
)))
1623 if (!ranges_maybe_overlap_p (doffset1
, max_size1
, doffset2
, max_size2
))
1626 /* If there is must alias, there is no use disambiguating further. */
1627 || (known_eq (size1
, max_size1
) && known_eq (size2
, max_size2
)))
1629 int res
= nonoverlapping_component_refs_since_match_p (base1
, ref1
,
1632 return !nonoverlapping_component_refs_p (ref1
, ref2
);
1636 /* Do access-path based disambiguation. */
1638 && (handled_component_p (ref1
) || handled_component_p (ref2
)))
1639 return aliasing_component_refs_p (ref1
,
1640 ref1_alias_set
, base1_alias_set
,
1643 ref2_alias_set
, base2_alias_set
,
1644 offset2
, max_size2
);
1649 /* Return true if two indirect references based on *PTR1
1650 and *PTR2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and
1651 [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. *PTR1 and *PTR2 have
1652 the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1
1653 in which case they are computed on-demand. REF1 and REF2
1654 if non-NULL are the complete memory reference trees. */
1657 indirect_refs_may_alias_p (tree ref1 ATTRIBUTE_UNUSED
, tree base1
,
1658 poly_int64 offset1
, poly_int64 max_size1
,
1660 alias_set_type ref1_alias_set
,
1661 alias_set_type base1_alias_set
,
1662 tree ref2 ATTRIBUTE_UNUSED
, tree base2
,
1663 poly_int64 offset2
, poly_int64 max_size2
,
1665 alias_set_type ref2_alias_set
,
1666 alias_set_type base2_alias_set
, bool tbaa_p
)
1670 tree ptrtype1
, ptrtype2
;
1672 gcc_checking_assert ((TREE_CODE (base1
) == MEM_REF
1673 || TREE_CODE (base1
) == TARGET_MEM_REF
)
1674 && (TREE_CODE (base2
) == MEM_REF
1675 || TREE_CODE (base2
) == TARGET_MEM_REF
));
1677 ptr1
= TREE_OPERAND (base1
, 0);
1678 ptr2
= TREE_OPERAND (base2
, 0);
1680 /* If both bases are based on pointers they cannot alias if they may not
1681 point to the same memory object or if they point to the same object
1682 and the accesses do not overlap. */
1683 if ((!cfun
|| gimple_in_ssa_p (cfun
))
1684 && operand_equal_p (ptr1
, ptr2
, 0)
1685 && (((TREE_CODE (base1
) != TARGET_MEM_REF
1686 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1687 && (TREE_CODE (base2
) != TARGET_MEM_REF
1688 || (!TMR_INDEX (base2
) && !TMR_INDEX2 (base2
))))
1689 || (TREE_CODE (base1
) == TARGET_MEM_REF
1690 && TREE_CODE (base2
) == TARGET_MEM_REF
1691 && (TMR_STEP (base1
) == TMR_STEP (base2
)
1692 || (TMR_STEP (base1
) && TMR_STEP (base2
)
1693 && operand_equal_p (TMR_STEP (base1
),
1694 TMR_STEP (base2
), 0)))
1695 && (TMR_INDEX (base1
) == TMR_INDEX (base2
)
1696 || (TMR_INDEX (base1
) && TMR_INDEX (base2
)
1697 && operand_equal_p (TMR_INDEX (base1
),
1698 TMR_INDEX (base2
), 0)))
1699 && (TMR_INDEX2 (base1
) == TMR_INDEX2 (base2
)
1700 || (TMR_INDEX2 (base1
) && TMR_INDEX2 (base2
)
1701 && operand_equal_p (TMR_INDEX2 (base1
),
1702 TMR_INDEX2 (base2
), 0))))))
1704 poly_offset_int moff1
= mem_ref_offset (base1
) << LOG2_BITS_PER_UNIT
;
1705 poly_offset_int moff2
= mem_ref_offset (base2
) << LOG2_BITS_PER_UNIT
;
1706 if (!ranges_maybe_overlap_p (offset1
+ moff1
, max_size1
,
1707 offset2
+ moff2
, max_size2
))
1709 /* If there is must alias, there is no use disambiguating further. */
1710 if (known_eq (size1
, max_size1
) && known_eq (size2
, max_size2
))
1714 int res
= nonoverlapping_component_refs_since_match_p (NULL
, ref1
,
1720 if (!ptr_derefs_may_alias_p (ptr1
, ptr2
))
1723 /* Disambiguations that rely on strict aliasing rules follow. */
1724 if (!flag_strict_aliasing
|| !tbaa_p
)
1727 ptrtype1
= TREE_TYPE (TREE_OPERAND (base1
, 1));
1728 ptrtype2
= TREE_TYPE (TREE_OPERAND (base2
, 1));
1730 /* If the alias set for a pointer access is zero all bets are off. */
1731 if (base1_alias_set
== 0
1732 || base2_alias_set
== 0)
1735 /* Do type-based disambiguation. */
1736 if (base1_alias_set
!= base2_alias_set
1737 && !alias_sets_conflict_p (base1_alias_set
, base2_alias_set
))
1740 /* If either reference is view-converted, give up now. */
1741 if (same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (ptrtype1
)) != 1
1742 || same_type_for_tbaa (TREE_TYPE (base2
), TREE_TYPE (ptrtype2
)) != 1)
1745 /* If both references are through the same type, they do not alias
1746 if the accesses do not overlap. This does extra disambiguation
1747 for mixed/pointer accesses but requires strict aliasing. */
1748 if ((TREE_CODE (base1
) != TARGET_MEM_REF
1749 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1750 && (TREE_CODE (base2
) != TARGET_MEM_REF
1751 || (!TMR_INDEX (base2
) && !TMR_INDEX2 (base2
)))
1752 && same_type_for_tbaa (TREE_TYPE (ptrtype1
),
1753 TREE_TYPE (ptrtype2
)) == 1
1754 /* But avoid treating arrays as "objects", instead assume they
1755 can overlap by an exact multiple of their element size.
1756 See gcc.dg/torture/alias-2.c. */
1757 && TREE_CODE (TREE_TYPE (ptrtype1
)) != ARRAY_TYPE
)
1759 if (!ranges_maybe_overlap_p (offset1
, max_size1
, offset2
, max_size2
))
1762 || (known_eq (size1
, max_size1
) && known_eq (size2
, max_size2
)))
1764 int res
= nonoverlapping_component_refs_since_match_p (base1
, ref1
,
1767 return !nonoverlapping_component_refs_p (ref1
, ref2
);
1771 /* Do access-path based disambiguation. */
1773 && (handled_component_p (ref1
) || handled_component_p (ref2
)))
1774 return aliasing_component_refs_p (ref1
,
1775 ref1_alias_set
, base1_alias_set
,
1778 ref2_alias_set
, base2_alias_set
,
1779 offset2
, max_size2
);
1784 /* Return true, if the two memory references REF1 and REF2 may alias. */
1787 refs_may_alias_p_2 (ao_ref
*ref1
, ao_ref
*ref2
, bool tbaa_p
)
1790 poly_int64 offset1
= 0, offset2
= 0;
1791 poly_int64 max_size1
= -1, max_size2
= -1;
1792 bool var1_p
, var2_p
, ind1_p
, ind2_p
;
1794 gcc_checking_assert ((!ref1
->ref
1795 || TREE_CODE (ref1
->ref
) == SSA_NAME
1796 || DECL_P (ref1
->ref
)
1797 || TREE_CODE (ref1
->ref
) == STRING_CST
1798 || handled_component_p (ref1
->ref
)
1799 || TREE_CODE (ref1
->ref
) == MEM_REF
1800 || TREE_CODE (ref1
->ref
) == TARGET_MEM_REF
)
1802 || TREE_CODE (ref2
->ref
) == SSA_NAME
1803 || DECL_P (ref2
->ref
)
1804 || TREE_CODE (ref2
->ref
) == STRING_CST
1805 || handled_component_p (ref2
->ref
)
1806 || TREE_CODE (ref2
->ref
) == MEM_REF
1807 || TREE_CODE (ref2
->ref
) == TARGET_MEM_REF
));
1809 /* Decompose the references into their base objects and the access. */
1810 base1
= ao_ref_base (ref1
);
1811 offset1
= ref1
->offset
;
1812 max_size1
= ref1
->max_size
;
1813 base2
= ao_ref_base (ref2
);
1814 offset2
= ref2
->offset
;
1815 max_size2
= ref2
->max_size
;
1817 /* We can end up with registers or constants as bases for example from
1818 *D.1663_44 = VIEW_CONVERT_EXPR<struct DB_LSN>(__tmp$B0F64_59);
1819 which is seen as a struct copy. */
1820 if (TREE_CODE (base1
) == SSA_NAME
1821 || TREE_CODE (base1
) == CONST_DECL
1822 || TREE_CODE (base1
) == CONSTRUCTOR
1823 || TREE_CODE (base1
) == ADDR_EXPR
1824 || CONSTANT_CLASS_P (base1
)
1825 || TREE_CODE (base2
) == SSA_NAME
1826 || TREE_CODE (base2
) == CONST_DECL
1827 || TREE_CODE (base2
) == CONSTRUCTOR
1828 || TREE_CODE (base2
) == ADDR_EXPR
1829 || CONSTANT_CLASS_P (base2
))
1832 /* We can end up referring to code via function and label decls.
1833 As we likely do not properly track code aliases conservatively
1835 if (TREE_CODE (base1
) == FUNCTION_DECL
1836 || TREE_CODE (base1
) == LABEL_DECL
1837 || TREE_CODE (base2
) == FUNCTION_DECL
1838 || TREE_CODE (base2
) == LABEL_DECL
)
1841 /* Two volatile accesses always conflict. */
1842 if (ref1
->volatile_p
1843 && ref2
->volatile_p
)
1846 /* Defer to simple offset based disambiguation if we have
1847 references based on two decls. Do this before defering to
1848 TBAA to handle must-alias cases in conformance with the
1849 GCC extension of allowing type-punning through unions. */
1850 var1_p
= DECL_P (base1
);
1851 var2_p
= DECL_P (base2
);
1852 if (var1_p
&& var2_p
)
1853 return decl_refs_may_alias_p (ref1
->ref
, base1
, offset1
, max_size1
,
1855 ref2
->ref
, base2
, offset2
, max_size2
,
1858 /* Handle restrict based accesses.
1859 ??? ao_ref_base strips inner MEM_REF [&decl], recover from that
1861 tree rbase1
= base1
;
1862 tree rbase2
= base2
;
1867 while (handled_component_p (rbase1
))
1868 rbase1
= TREE_OPERAND (rbase1
, 0);
1874 while (handled_component_p (rbase2
))
1875 rbase2
= TREE_OPERAND (rbase2
, 0);
1877 if (rbase1
&& rbase2
1878 && (TREE_CODE (base1
) == MEM_REF
|| TREE_CODE (base1
) == TARGET_MEM_REF
)
1879 && (TREE_CODE (base2
) == MEM_REF
|| TREE_CODE (base2
) == TARGET_MEM_REF
)
1880 /* If the accesses are in the same restrict clique... */
1881 && MR_DEPENDENCE_CLIQUE (base1
) == MR_DEPENDENCE_CLIQUE (base2
)
1882 /* But based on different pointers they do not alias. */
1883 && MR_DEPENDENCE_BASE (base1
) != MR_DEPENDENCE_BASE (base2
))
1886 ind1_p
= (TREE_CODE (base1
) == MEM_REF
1887 || TREE_CODE (base1
) == TARGET_MEM_REF
);
1888 ind2_p
= (TREE_CODE (base2
) == MEM_REF
1889 || TREE_CODE (base2
) == TARGET_MEM_REF
);
1891 /* Canonicalize the pointer-vs-decl case. */
1892 if (ind1_p
&& var2_p
)
1894 std::swap (offset1
, offset2
);
1895 std::swap (max_size1
, max_size2
);
1896 std::swap (base1
, base2
);
1897 std::swap (ref1
, ref2
);
1904 /* First defer to TBAA if possible. */
1906 && flag_strict_aliasing
1907 && !alias_sets_conflict_p (ao_ref_alias_set (ref1
),
1908 ao_ref_alias_set (ref2
)))
1911 /* If the reference is based on a pointer that points to memory
1912 that may not be written to then the other reference cannot possibly
1914 if ((TREE_CODE (TREE_OPERAND (base2
, 0)) == SSA_NAME
1915 && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base2
, 0)))
1917 && TREE_CODE (TREE_OPERAND (base1
, 0)) == SSA_NAME
1918 && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base1
, 0))))
1921 /* Dispatch to the pointer-vs-decl or pointer-vs-pointer disambiguators. */
1922 if (var1_p
&& ind2_p
)
1923 return indirect_ref_may_alias_decl_p (ref2
->ref
, base2
,
1924 offset2
, max_size2
, ref2
->size
,
1925 ao_ref_alias_set (ref2
),
1926 ao_ref_base_alias_set (ref2
),
1928 offset1
, max_size1
, ref1
->size
,
1929 ao_ref_alias_set (ref1
),
1930 ao_ref_base_alias_set (ref1
),
1932 else if (ind1_p
&& ind2_p
)
1933 return indirect_refs_may_alias_p (ref1
->ref
, base1
,
1934 offset1
, max_size1
, ref1
->size
,
1935 ao_ref_alias_set (ref1
),
1936 ao_ref_base_alias_set (ref1
),
1938 offset2
, max_size2
, ref2
->size
,
1939 ao_ref_alias_set (ref2
),
1940 ao_ref_base_alias_set (ref2
),
1946 /* Return true, if the two memory references REF1 and REF2 may alias
1947 and update statistics. */
1950 refs_may_alias_p_1 (ao_ref
*ref1
, ao_ref
*ref2
, bool tbaa_p
)
1952 bool res
= refs_may_alias_p_2 (ref1
, ref2
, tbaa_p
);
1954 ++alias_stats
.refs_may_alias_p_may_alias
;
1956 ++alias_stats
.refs_may_alias_p_no_alias
;
1961 refs_may_alias_p (tree ref1
, ao_ref
*ref2
, bool tbaa_p
)
1964 ao_ref_init (&r1
, ref1
);
1965 return refs_may_alias_p_1 (&r1
, ref2
, tbaa_p
);
1969 refs_may_alias_p (tree ref1
, tree ref2
, bool tbaa_p
)
1972 ao_ref_init (&r1
, ref1
);
1973 ao_ref_init (&r2
, ref2
);
1974 return refs_may_alias_p_1 (&r1
, &r2
, tbaa_p
);
1977 /* Returns true if there is a anti-dependence for the STORE that
1978 executes after the LOAD. */
1981 refs_anti_dependent_p (tree load
, tree store
)
1984 ao_ref_init (&r1
, load
);
1985 ao_ref_init (&r2
, store
);
1986 return refs_may_alias_p_1 (&r1
, &r2
, false);
1989 /* Returns true if there is a output dependence for the stores
1990 STORE1 and STORE2. */
1993 refs_output_dependent_p (tree store1
, tree store2
)
1996 ao_ref_init (&r1
, store1
);
1997 ao_ref_init (&r2
, store2
);
1998 return refs_may_alias_p_1 (&r1
, &r2
, false);
2001 /* If the call CALL may use the memory reference REF return true,
2002 otherwise return false. */
2005 ref_maybe_used_by_call_p_1 (gcall
*call
, ao_ref
*ref
, bool tbaa_p
)
2009 int flags
= gimple_call_flags (call
);
2011 /* Const functions without a static chain do not implicitly use memory. */
2012 if (!gimple_call_chain (call
)
2013 && (flags
& (ECF_CONST
|ECF_NOVOPS
)))
2016 base
= ao_ref_base (ref
);
2020 /* A call that is not without side-effects might involve volatile
2021 accesses and thus conflicts with all other volatile accesses. */
2022 if (ref
->volatile_p
)
2025 /* If the reference is based on a decl that is not aliased the call
2026 cannot possibly use it. */
2028 && !may_be_aliased (base
)
2029 /* But local statics can be used through recursion. */
2030 && !is_global_var (base
))
2033 callee
= gimple_call_fndecl (call
);
2035 /* Handle those builtin functions explicitly that do not act as
2036 escape points. See tree-ssa-structalias.c:find_func_aliases
2037 for the list of builtins we might need to handle here. */
2038 if (callee
!= NULL_TREE
2039 && gimple_call_builtin_p (call
, BUILT_IN_NORMAL
))
2040 switch (DECL_FUNCTION_CODE (callee
))
2042 /* All the following functions read memory pointed to by
2043 their second argument. strcat/strncat additionally
2044 reads memory pointed to by the first argument. */
2045 case BUILT_IN_STRCAT
:
2046 case BUILT_IN_STRNCAT
:
2049 ao_ref_init_from_ptr_and_size (&dref
,
2050 gimple_call_arg (call
, 0),
2052 if (refs_may_alias_p_1 (&dref
, ref
, false))
2056 case BUILT_IN_STRCPY
:
2057 case BUILT_IN_STRNCPY
:
2058 case BUILT_IN_MEMCPY
:
2059 case BUILT_IN_MEMMOVE
:
2060 case BUILT_IN_MEMPCPY
:
2061 case BUILT_IN_STPCPY
:
2062 case BUILT_IN_STPNCPY
:
2063 case BUILT_IN_TM_MEMCPY
:
2064 case BUILT_IN_TM_MEMMOVE
:
2067 tree size
= NULL_TREE
;
2068 if (gimple_call_num_args (call
) == 3)
2069 size
= gimple_call_arg (call
, 2);
2070 ao_ref_init_from_ptr_and_size (&dref
,
2071 gimple_call_arg (call
, 1),
2073 return refs_may_alias_p_1 (&dref
, ref
, false);
2075 case BUILT_IN_STRCAT_CHK
:
2076 case BUILT_IN_STRNCAT_CHK
:
2079 ao_ref_init_from_ptr_and_size (&dref
,
2080 gimple_call_arg (call
, 0),
2082 if (refs_may_alias_p_1 (&dref
, ref
, false))
2086 case BUILT_IN_STRCPY_CHK
:
2087 case BUILT_IN_STRNCPY_CHK
:
2088 case BUILT_IN_MEMCPY_CHK
:
2089 case BUILT_IN_MEMMOVE_CHK
:
2090 case BUILT_IN_MEMPCPY_CHK
:
2091 case BUILT_IN_STPCPY_CHK
:
2092 case BUILT_IN_STPNCPY_CHK
:
2095 tree size
= NULL_TREE
;
2096 if (gimple_call_num_args (call
) == 4)
2097 size
= gimple_call_arg (call
, 2);
2098 ao_ref_init_from_ptr_and_size (&dref
,
2099 gimple_call_arg (call
, 1),
2101 return refs_may_alias_p_1 (&dref
, ref
, false);
2103 case BUILT_IN_BCOPY
:
2106 tree size
= gimple_call_arg (call
, 2);
2107 ao_ref_init_from_ptr_and_size (&dref
,
2108 gimple_call_arg (call
, 0),
2110 return refs_may_alias_p_1 (&dref
, ref
, false);
2113 /* The following functions read memory pointed to by their
2115 CASE_BUILT_IN_TM_LOAD (1):
2116 CASE_BUILT_IN_TM_LOAD (2):
2117 CASE_BUILT_IN_TM_LOAD (4):
2118 CASE_BUILT_IN_TM_LOAD (8):
2119 CASE_BUILT_IN_TM_LOAD (FLOAT
):
2120 CASE_BUILT_IN_TM_LOAD (DOUBLE
):
2121 CASE_BUILT_IN_TM_LOAD (LDOUBLE
):
2122 CASE_BUILT_IN_TM_LOAD (M64
):
2123 CASE_BUILT_IN_TM_LOAD (M128
):
2124 CASE_BUILT_IN_TM_LOAD (M256
):
2125 case BUILT_IN_TM_LOG
:
2126 case BUILT_IN_TM_LOG_1
:
2127 case BUILT_IN_TM_LOG_2
:
2128 case BUILT_IN_TM_LOG_4
:
2129 case BUILT_IN_TM_LOG_8
:
2130 case BUILT_IN_TM_LOG_FLOAT
:
2131 case BUILT_IN_TM_LOG_DOUBLE
:
2132 case BUILT_IN_TM_LOG_LDOUBLE
:
2133 case BUILT_IN_TM_LOG_M64
:
2134 case BUILT_IN_TM_LOG_M128
:
2135 case BUILT_IN_TM_LOG_M256
:
2136 return ptr_deref_may_alias_ref_p_1 (gimple_call_arg (call
, 0), ref
);
2138 /* These read memory pointed to by the first argument. */
2139 case BUILT_IN_STRDUP
:
2140 case BUILT_IN_STRNDUP
:
2141 case BUILT_IN_REALLOC
:
2144 tree size
= NULL_TREE
;
2145 if (gimple_call_num_args (call
) == 2)
2146 size
= gimple_call_arg (call
, 1);
2147 ao_ref_init_from_ptr_and_size (&dref
,
2148 gimple_call_arg (call
, 0),
2150 return refs_may_alias_p_1 (&dref
, ref
, false);
2152 /* These read memory pointed to by the first argument. */
2153 case BUILT_IN_INDEX
:
2154 case BUILT_IN_STRCHR
:
2155 case BUILT_IN_STRRCHR
:
2158 ao_ref_init_from_ptr_and_size (&dref
,
2159 gimple_call_arg (call
, 0),
2161 return refs_may_alias_p_1 (&dref
, ref
, false);
2163 /* These read memory pointed to by the first argument with size
2164 in the third argument. */
2165 case BUILT_IN_MEMCHR
:
2168 ao_ref_init_from_ptr_and_size (&dref
,
2169 gimple_call_arg (call
, 0),
2170 gimple_call_arg (call
, 2));
2171 return refs_may_alias_p_1 (&dref
, ref
, false);
2173 /* These read memory pointed to by the first and second arguments. */
2174 case BUILT_IN_STRSTR
:
2175 case BUILT_IN_STRPBRK
:
2178 ao_ref_init_from_ptr_and_size (&dref
,
2179 gimple_call_arg (call
, 0),
2181 if (refs_may_alias_p_1 (&dref
, ref
, false))
2183 ao_ref_init_from_ptr_and_size (&dref
,
2184 gimple_call_arg (call
, 1),
2186 return refs_may_alias_p_1 (&dref
, ref
, false);
2189 /* The following builtins do not read from memory. */
2191 case BUILT_IN_MALLOC
:
2192 case BUILT_IN_POSIX_MEMALIGN
:
2193 case BUILT_IN_ALIGNED_ALLOC
:
2194 case BUILT_IN_CALLOC
:
2195 CASE_BUILT_IN_ALLOCA
:
2196 case BUILT_IN_STACK_SAVE
:
2197 case BUILT_IN_STACK_RESTORE
:
2198 case BUILT_IN_MEMSET
:
2199 case BUILT_IN_TM_MEMSET
:
2200 case BUILT_IN_MEMSET_CHK
:
2201 case BUILT_IN_FREXP
:
2202 case BUILT_IN_FREXPF
:
2203 case BUILT_IN_FREXPL
:
2204 case BUILT_IN_GAMMA_R
:
2205 case BUILT_IN_GAMMAF_R
:
2206 case BUILT_IN_GAMMAL_R
:
2207 case BUILT_IN_LGAMMA_R
:
2208 case BUILT_IN_LGAMMAF_R
:
2209 case BUILT_IN_LGAMMAL_R
:
2211 case BUILT_IN_MODFF
:
2212 case BUILT_IN_MODFL
:
2213 case BUILT_IN_REMQUO
:
2214 case BUILT_IN_REMQUOF
:
2215 case BUILT_IN_REMQUOL
:
2216 case BUILT_IN_SINCOS
:
2217 case BUILT_IN_SINCOSF
:
2218 case BUILT_IN_SINCOSL
:
2219 case BUILT_IN_ASSUME_ALIGNED
:
2220 case BUILT_IN_VA_END
:
2222 /* __sync_* builtins and some OpenMP builtins act as threading
2224 #undef DEF_SYNC_BUILTIN
2225 #define DEF_SYNC_BUILTIN(ENUM, NAME, TYPE, ATTRS) case ENUM:
2226 #include "sync-builtins.def"
2227 #undef DEF_SYNC_BUILTIN
2228 case BUILT_IN_GOMP_ATOMIC_START
:
2229 case BUILT_IN_GOMP_ATOMIC_END
:
2230 case BUILT_IN_GOMP_BARRIER
:
2231 case BUILT_IN_GOMP_BARRIER_CANCEL
:
2232 case BUILT_IN_GOMP_TASKWAIT
:
2233 case BUILT_IN_GOMP_TASKGROUP_END
:
2234 case BUILT_IN_GOMP_CRITICAL_START
:
2235 case BUILT_IN_GOMP_CRITICAL_END
:
2236 case BUILT_IN_GOMP_CRITICAL_NAME_START
:
2237 case BUILT_IN_GOMP_CRITICAL_NAME_END
:
2238 case BUILT_IN_GOMP_LOOP_END
:
2239 case BUILT_IN_GOMP_LOOP_END_CANCEL
:
2240 case BUILT_IN_GOMP_ORDERED_START
:
2241 case BUILT_IN_GOMP_ORDERED_END
:
2242 case BUILT_IN_GOMP_SECTIONS_END
:
2243 case BUILT_IN_GOMP_SECTIONS_END_CANCEL
:
2244 case BUILT_IN_GOMP_SINGLE_COPY_START
:
2245 case BUILT_IN_GOMP_SINGLE_COPY_END
:
2249 /* Fallthru to general call handling. */;
2252 /* Check if base is a global static variable that is not read
2254 if (callee
!= NULL_TREE
&& VAR_P (base
) && TREE_STATIC (base
))
2256 struct cgraph_node
*node
= cgraph_node::get (callee
);
2259 /* FIXME: Callee can be an OMP builtin that does not have a call graph
2260 node yet. We should enforce that there are nodes for all decls in the
2261 IL and remove this check instead. */
2263 && (not_read
= ipa_reference_get_not_read_global (node
))
2264 && bitmap_bit_p (not_read
, ipa_reference_var_uid (base
)))
2268 /* Check if the base variable is call-used. */
2271 if (pt_solution_includes (gimple_call_use_set (call
), base
))
2274 else if ((TREE_CODE (base
) == MEM_REF
2275 || TREE_CODE (base
) == TARGET_MEM_REF
)
2276 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
)
2278 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (TREE_OPERAND (base
, 0));
2282 if (pt_solutions_intersect (gimple_call_use_set (call
), &pi
->pt
))
2288 /* Inspect call arguments for passed-by-value aliases. */
2290 for (i
= 0; i
< gimple_call_num_args (call
); ++i
)
2292 tree op
= gimple_call_arg (call
, i
);
2293 int flags
= gimple_call_arg_flags (call
, i
);
2295 if (flags
& EAF_UNUSED
)
2298 if (TREE_CODE (op
) == WITH_SIZE_EXPR
)
2299 op
= TREE_OPERAND (op
, 0);
2301 if (TREE_CODE (op
) != SSA_NAME
2302 && !is_gimple_min_invariant (op
))
2305 ao_ref_init (&r
, op
);
2306 if (refs_may_alias_p_1 (&r
, ref
, tbaa_p
))
2315 ref_maybe_used_by_call_p (gcall
*call
, ao_ref
*ref
, bool tbaa_p
)
2318 res
= ref_maybe_used_by_call_p_1 (call
, ref
, tbaa_p
);
2320 ++alias_stats
.ref_maybe_used_by_call_p_may_alias
;
2322 ++alias_stats
.ref_maybe_used_by_call_p_no_alias
;
2327 /* If the statement STMT may use the memory reference REF return
2328 true, otherwise return false. */
2331 ref_maybe_used_by_stmt_p (gimple
*stmt
, ao_ref
*ref
, bool tbaa_p
)
2333 if (is_gimple_assign (stmt
))
2337 /* All memory assign statements are single. */
2338 if (!gimple_assign_single_p (stmt
))
2341 rhs
= gimple_assign_rhs1 (stmt
);
2342 if (is_gimple_reg (rhs
)
2343 || is_gimple_min_invariant (rhs
)
2344 || gimple_assign_rhs_code (stmt
) == CONSTRUCTOR
)
2347 return refs_may_alias_p (rhs
, ref
, tbaa_p
);
2349 else if (is_gimple_call (stmt
))
2350 return ref_maybe_used_by_call_p (as_a
<gcall
*> (stmt
), ref
, tbaa_p
);
2351 else if (greturn
*return_stmt
= dyn_cast
<greturn
*> (stmt
))
2353 tree retval
= gimple_return_retval (return_stmt
);
2355 && TREE_CODE (retval
) != SSA_NAME
2356 && !is_gimple_min_invariant (retval
)
2357 && refs_may_alias_p (retval
, ref
, tbaa_p
))
2359 /* If ref escapes the function then the return acts as a use. */
2360 tree base
= ao_ref_base (ref
);
2363 else if (DECL_P (base
))
2364 return is_global_var (base
);
2365 else if (TREE_CODE (base
) == MEM_REF
2366 || TREE_CODE (base
) == TARGET_MEM_REF
)
2367 return ptr_deref_may_alias_global_p (TREE_OPERAND (base
, 0));
2375 ref_maybe_used_by_stmt_p (gimple
*stmt
, tree ref
, bool tbaa_p
)
2378 ao_ref_init (&r
, ref
);
2379 return ref_maybe_used_by_stmt_p (stmt
, &r
, tbaa_p
);
2382 /* If the call in statement CALL may clobber the memory reference REF
2383 return true, otherwise return false. */
2386 call_may_clobber_ref_p_1 (gcall
*call
, ao_ref
*ref
)
2391 /* If the call is pure or const it cannot clobber anything. */
2392 if (gimple_call_flags (call
)
2393 & (ECF_PURE
|ECF_CONST
|ECF_LOOPING_CONST_OR_PURE
|ECF_NOVOPS
))
2395 if (gimple_call_internal_p (call
))
2396 switch (gimple_call_internal_fn (call
))
2398 /* Treat these internal calls like ECF_PURE for aliasing,
2399 they don't write to any memory the program should care about.
2400 They have important other side-effects, and read memory,
2401 so can't be ECF_NOVOPS. */
2402 case IFN_UBSAN_NULL
:
2403 case IFN_UBSAN_BOUNDS
:
2404 case IFN_UBSAN_VPTR
:
2405 case IFN_UBSAN_OBJECT_SIZE
:
2407 case IFN_ASAN_CHECK
:
2413 base
= ao_ref_base (ref
);
2417 if (TREE_CODE (base
) == SSA_NAME
2418 || CONSTANT_CLASS_P (base
))
2421 /* A call that is not without side-effects might involve volatile
2422 accesses and thus conflicts with all other volatile accesses. */
2423 if (ref
->volatile_p
)
2426 /* If the reference is based on a decl that is not aliased the call
2427 cannot possibly clobber it. */
2429 && !may_be_aliased (base
)
2430 /* But local non-readonly statics can be modified through recursion
2431 or the call may implement a threading barrier which we must
2432 treat as may-def. */
2433 && (TREE_READONLY (base
)
2434 || !is_global_var (base
)))
2437 /* If the reference is based on a pointer that points to memory
2438 that may not be written to then the call cannot possibly clobber it. */
2439 if ((TREE_CODE (base
) == MEM_REF
2440 || TREE_CODE (base
) == TARGET_MEM_REF
)
2441 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
2442 && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base
, 0)))
2445 callee
= gimple_call_fndecl (call
);
2447 /* Handle those builtin functions explicitly that do not act as
2448 escape points. See tree-ssa-structalias.c:find_func_aliases
2449 for the list of builtins we might need to handle here. */
2450 if (callee
!= NULL_TREE
2451 && gimple_call_builtin_p (call
, BUILT_IN_NORMAL
))
2452 switch (DECL_FUNCTION_CODE (callee
))
2454 /* All the following functions clobber memory pointed to by
2455 their first argument. */
2456 case BUILT_IN_STRCPY
:
2457 case BUILT_IN_STRNCPY
:
2458 case BUILT_IN_MEMCPY
:
2459 case BUILT_IN_MEMMOVE
:
2460 case BUILT_IN_MEMPCPY
:
2461 case BUILT_IN_STPCPY
:
2462 case BUILT_IN_STPNCPY
:
2463 case BUILT_IN_STRCAT
:
2464 case BUILT_IN_STRNCAT
:
2465 case BUILT_IN_MEMSET
:
2466 case BUILT_IN_TM_MEMSET
:
2467 CASE_BUILT_IN_TM_STORE (1):
2468 CASE_BUILT_IN_TM_STORE (2):
2469 CASE_BUILT_IN_TM_STORE (4):
2470 CASE_BUILT_IN_TM_STORE (8):
2471 CASE_BUILT_IN_TM_STORE (FLOAT
):
2472 CASE_BUILT_IN_TM_STORE (DOUBLE
):
2473 CASE_BUILT_IN_TM_STORE (LDOUBLE
):
2474 CASE_BUILT_IN_TM_STORE (M64
):
2475 CASE_BUILT_IN_TM_STORE (M128
):
2476 CASE_BUILT_IN_TM_STORE (M256
):
2477 case BUILT_IN_TM_MEMCPY
:
2478 case BUILT_IN_TM_MEMMOVE
:
2481 tree size
= NULL_TREE
;
2482 /* Don't pass in size for strncat, as the maximum size
2483 is strlen (dest) + n + 1 instead of n, resp.
2484 n + 1 at dest + strlen (dest), but strlen (dest) isn't
2486 if (gimple_call_num_args (call
) == 3
2487 && DECL_FUNCTION_CODE (callee
) != BUILT_IN_STRNCAT
)
2488 size
= gimple_call_arg (call
, 2);
2489 ao_ref_init_from_ptr_and_size (&dref
,
2490 gimple_call_arg (call
, 0),
2492 return refs_may_alias_p_1 (&dref
, ref
, false);
2494 case BUILT_IN_STRCPY_CHK
:
2495 case BUILT_IN_STRNCPY_CHK
:
2496 case BUILT_IN_MEMCPY_CHK
:
2497 case BUILT_IN_MEMMOVE_CHK
:
2498 case BUILT_IN_MEMPCPY_CHK
:
2499 case BUILT_IN_STPCPY_CHK
:
2500 case BUILT_IN_STPNCPY_CHK
:
2501 case BUILT_IN_STRCAT_CHK
:
2502 case BUILT_IN_STRNCAT_CHK
:
2503 case BUILT_IN_MEMSET_CHK
:
2506 tree size
= NULL_TREE
;
2507 /* Don't pass in size for __strncat_chk, as the maximum size
2508 is strlen (dest) + n + 1 instead of n, resp.
2509 n + 1 at dest + strlen (dest), but strlen (dest) isn't
2511 if (gimple_call_num_args (call
) == 4
2512 && DECL_FUNCTION_CODE (callee
) != BUILT_IN_STRNCAT_CHK
)
2513 size
= gimple_call_arg (call
, 2);
2514 ao_ref_init_from_ptr_and_size (&dref
,
2515 gimple_call_arg (call
, 0),
2517 return refs_may_alias_p_1 (&dref
, ref
, false);
2519 case BUILT_IN_BCOPY
:
2522 tree size
= gimple_call_arg (call
, 2);
2523 ao_ref_init_from_ptr_and_size (&dref
,
2524 gimple_call_arg (call
, 1),
2526 return refs_may_alias_p_1 (&dref
, ref
, false);
2528 /* Allocating memory does not have any side-effects apart from
2529 being the definition point for the pointer. */
2530 case BUILT_IN_MALLOC
:
2531 case BUILT_IN_ALIGNED_ALLOC
:
2532 case BUILT_IN_CALLOC
:
2533 case BUILT_IN_STRDUP
:
2534 case BUILT_IN_STRNDUP
:
2535 /* Unix98 specifies that errno is set on allocation failure. */
2537 && targetm
.ref_may_alias_errno (ref
))
2540 case BUILT_IN_STACK_SAVE
:
2541 CASE_BUILT_IN_ALLOCA
:
2542 case BUILT_IN_ASSUME_ALIGNED
:
2544 /* But posix_memalign stores a pointer into the memory pointed to
2545 by its first argument. */
2546 case BUILT_IN_POSIX_MEMALIGN
:
2548 tree ptrptr
= gimple_call_arg (call
, 0);
2550 ao_ref_init_from_ptr_and_size (&dref
, ptrptr
,
2551 TYPE_SIZE_UNIT (ptr_type_node
));
2552 return (refs_may_alias_p_1 (&dref
, ref
, false)
2554 && targetm
.ref_may_alias_errno (ref
)));
2556 /* Freeing memory kills the pointed-to memory. More importantly
2557 the call has to serve as a barrier for moving loads and stores
2560 case BUILT_IN_VA_END
:
2562 tree ptr
= gimple_call_arg (call
, 0);
2563 return ptr_deref_may_alias_ref_p_1 (ptr
, ref
);
2565 /* Realloc serves both as allocation point and deallocation point. */
2566 case BUILT_IN_REALLOC
:
2568 tree ptr
= gimple_call_arg (call
, 0);
2569 /* Unix98 specifies that errno is set on allocation failure. */
2570 return ((flag_errno_math
2571 && targetm
.ref_may_alias_errno (ref
))
2572 || ptr_deref_may_alias_ref_p_1 (ptr
, ref
));
2574 case BUILT_IN_GAMMA_R
:
2575 case BUILT_IN_GAMMAF_R
:
2576 case BUILT_IN_GAMMAL_R
:
2577 case BUILT_IN_LGAMMA_R
:
2578 case BUILT_IN_LGAMMAF_R
:
2579 case BUILT_IN_LGAMMAL_R
:
2581 tree out
= gimple_call_arg (call
, 1);
2582 if (ptr_deref_may_alias_ref_p_1 (out
, ref
))
2584 if (flag_errno_math
)
2588 case BUILT_IN_FREXP
:
2589 case BUILT_IN_FREXPF
:
2590 case BUILT_IN_FREXPL
:
2592 case BUILT_IN_MODFF
:
2593 case BUILT_IN_MODFL
:
2595 tree out
= gimple_call_arg (call
, 1);
2596 return ptr_deref_may_alias_ref_p_1 (out
, ref
);
2598 case BUILT_IN_REMQUO
:
2599 case BUILT_IN_REMQUOF
:
2600 case BUILT_IN_REMQUOL
:
2602 tree out
= gimple_call_arg (call
, 2);
2603 if (ptr_deref_may_alias_ref_p_1 (out
, ref
))
2605 if (flag_errno_math
)
2609 case BUILT_IN_SINCOS
:
2610 case BUILT_IN_SINCOSF
:
2611 case BUILT_IN_SINCOSL
:
2613 tree sin
= gimple_call_arg (call
, 1);
2614 tree cos
= gimple_call_arg (call
, 2);
2615 return (ptr_deref_may_alias_ref_p_1 (sin
, ref
)
2616 || ptr_deref_may_alias_ref_p_1 (cos
, ref
));
2618 /* __sync_* builtins and some OpenMP builtins act as threading
2620 #undef DEF_SYNC_BUILTIN
2621 #define DEF_SYNC_BUILTIN(ENUM, NAME, TYPE, ATTRS) case ENUM:
2622 #include "sync-builtins.def"
2623 #undef DEF_SYNC_BUILTIN
2624 case BUILT_IN_GOMP_ATOMIC_START
:
2625 case BUILT_IN_GOMP_ATOMIC_END
:
2626 case BUILT_IN_GOMP_BARRIER
:
2627 case BUILT_IN_GOMP_BARRIER_CANCEL
:
2628 case BUILT_IN_GOMP_TASKWAIT
:
2629 case BUILT_IN_GOMP_TASKGROUP_END
:
2630 case BUILT_IN_GOMP_CRITICAL_START
:
2631 case BUILT_IN_GOMP_CRITICAL_END
:
2632 case BUILT_IN_GOMP_CRITICAL_NAME_START
:
2633 case BUILT_IN_GOMP_CRITICAL_NAME_END
:
2634 case BUILT_IN_GOMP_LOOP_END
:
2635 case BUILT_IN_GOMP_LOOP_END_CANCEL
:
2636 case BUILT_IN_GOMP_ORDERED_START
:
2637 case BUILT_IN_GOMP_ORDERED_END
:
2638 case BUILT_IN_GOMP_SECTIONS_END
:
2639 case BUILT_IN_GOMP_SECTIONS_END_CANCEL
:
2640 case BUILT_IN_GOMP_SINGLE_COPY_START
:
2641 case BUILT_IN_GOMP_SINGLE_COPY_END
:
2644 /* Fallthru to general call handling. */;
2647 /* Check if base is a global static variable that is not written
2649 if (callee
!= NULL_TREE
&& VAR_P (base
) && TREE_STATIC (base
))
2651 struct cgraph_node
*node
= cgraph_node::get (callee
);
2655 && (not_written
= ipa_reference_get_not_written_global (node
))
2656 && bitmap_bit_p (not_written
, ipa_reference_var_uid (base
)))
2660 /* Check if the base variable is call-clobbered. */
2662 return pt_solution_includes (gimple_call_clobber_set (call
), base
);
2663 else if ((TREE_CODE (base
) == MEM_REF
2664 || TREE_CODE (base
) == TARGET_MEM_REF
)
2665 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
)
2667 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (TREE_OPERAND (base
, 0));
2671 return pt_solutions_intersect (gimple_call_clobber_set (call
), &pi
->pt
);
2677 /* If the call in statement CALL may clobber the memory reference REF
2678 return true, otherwise return false. */
2681 call_may_clobber_ref_p (gcall
*call
, tree ref
)
2685 ao_ref_init (&r
, ref
);
2686 res
= call_may_clobber_ref_p_1 (call
, &r
);
2688 ++alias_stats
.call_may_clobber_ref_p_may_alias
;
2690 ++alias_stats
.call_may_clobber_ref_p_no_alias
;
2695 /* If the statement STMT may clobber the memory reference REF return true,
2696 otherwise return false. */
2699 stmt_may_clobber_ref_p_1 (gimple
*stmt
, ao_ref
*ref
, bool tbaa_p
)
2701 if (is_gimple_call (stmt
))
2703 tree lhs
= gimple_call_lhs (stmt
);
2705 && TREE_CODE (lhs
) != SSA_NAME
)
2708 ao_ref_init (&r
, lhs
);
2709 if (refs_may_alias_p_1 (ref
, &r
, tbaa_p
))
2713 return call_may_clobber_ref_p_1 (as_a
<gcall
*> (stmt
), ref
);
2715 else if (gimple_assign_single_p (stmt
))
2717 tree lhs
= gimple_assign_lhs (stmt
);
2718 if (TREE_CODE (lhs
) != SSA_NAME
)
2721 ao_ref_init (&r
, lhs
);
2722 return refs_may_alias_p_1 (ref
, &r
, tbaa_p
);
2725 else if (gimple_code (stmt
) == GIMPLE_ASM
)
2732 stmt_may_clobber_ref_p (gimple
*stmt
, tree ref
, bool tbaa_p
)
2735 ao_ref_init (&r
, ref
);
2736 return stmt_may_clobber_ref_p_1 (stmt
, &r
, tbaa_p
);
2739 /* Return true if store1 and store2 described by corresponding tuples
2740 <BASE, OFFSET, SIZE, MAX_SIZE> have the same size and store to the same
2744 same_addr_size_stores_p (tree base1
, poly_int64 offset1
, poly_int64 size1
,
2745 poly_int64 max_size1
,
2746 tree base2
, poly_int64 offset2
, poly_int64 size2
,
2747 poly_int64 max_size2
)
2749 /* Offsets need to be 0. */
2750 if (maybe_ne (offset1
, 0)
2751 || maybe_ne (offset2
, 0))
2754 bool base1_obj_p
= SSA_VAR_P (base1
);
2755 bool base2_obj_p
= SSA_VAR_P (base2
);
2757 /* We need one object. */
2758 if (base1_obj_p
== base2_obj_p
)
2760 tree obj
= base1_obj_p
? base1
: base2
;
2762 /* And we need one MEM_REF. */
2763 bool base1_memref_p
= TREE_CODE (base1
) == MEM_REF
;
2764 bool base2_memref_p
= TREE_CODE (base2
) == MEM_REF
;
2765 if (base1_memref_p
== base2_memref_p
)
2767 tree memref
= base1_memref_p
? base1
: base2
;
2769 /* Sizes need to be valid. */
2770 if (!known_size_p (max_size1
)
2771 || !known_size_p (max_size2
)
2772 || !known_size_p (size1
)
2773 || !known_size_p (size2
))
2776 /* Max_size needs to match size. */
2777 if (maybe_ne (max_size1
, size1
)
2778 || maybe_ne (max_size2
, size2
))
2781 /* Sizes need to match. */
2782 if (maybe_ne (size1
, size2
))
2786 /* Check that memref is a store to pointer with singleton points-to info. */
2787 if (!integer_zerop (TREE_OPERAND (memref
, 1)))
2789 tree ptr
= TREE_OPERAND (memref
, 0);
2790 if (TREE_CODE (ptr
) != SSA_NAME
)
2792 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (ptr
);
2793 unsigned int pt_uid
;
2795 || !pt_solution_singleton_or_null_p (&pi
->pt
, &pt_uid
))
2798 /* Be conservative with non-call exceptions when the address might
2800 if (cfun
->can_throw_non_call_exceptions
&& pi
->pt
.null
)
2803 /* Check that ptr points relative to obj. */
2804 unsigned int obj_uid
= DECL_PT_UID (obj
);
2805 if (obj_uid
!= pt_uid
)
2808 /* Check that the object size is the same as the store size. That ensures us
2809 that ptr points to the start of obj. */
2810 return (DECL_SIZE (obj
)
2811 && poly_int_tree_p (DECL_SIZE (obj
))
2812 && known_eq (wi::to_poly_offset (DECL_SIZE (obj
)), size1
));
2815 /* If STMT kills the memory reference REF return true, otherwise
2819 stmt_kills_ref_p (gimple
*stmt
, ao_ref
*ref
)
2821 if (!ao_ref_base (ref
))
2824 if (gimple_has_lhs (stmt
)
2825 && TREE_CODE (gimple_get_lhs (stmt
)) != SSA_NAME
2826 /* The assignment is not necessarily carried out if it can throw
2827 and we can catch it in the current function where we could inspect
2829 ??? We only need to care about the RHS throwing. For aggregate
2830 assignments or similar calls and non-call exceptions the LHS
2831 might throw as well. */
2832 && !stmt_can_throw_internal (cfun
, stmt
))
2834 tree lhs
= gimple_get_lhs (stmt
);
2835 /* If LHS is literally a base of the access we are done. */
2838 tree base
= ref
->ref
;
2839 tree innermost_dropped_array_ref
= NULL_TREE
;
2840 if (handled_component_p (base
))
2842 tree saved_lhs0
= NULL_TREE
;
2843 if (handled_component_p (lhs
))
2845 saved_lhs0
= TREE_OPERAND (lhs
, 0);
2846 TREE_OPERAND (lhs
, 0) = integer_zero_node
;
2850 /* Just compare the outermost handled component, if
2851 they are equal we have found a possible common
2853 tree saved_base0
= TREE_OPERAND (base
, 0);
2854 TREE_OPERAND (base
, 0) = integer_zero_node
;
2855 bool res
= operand_equal_p (lhs
, base
, 0);
2856 TREE_OPERAND (base
, 0) = saved_base0
;
2859 /* Remember if we drop an array-ref that we need to
2860 double-check not being at struct end. */
2861 if (TREE_CODE (base
) == ARRAY_REF
2862 || TREE_CODE (base
) == ARRAY_RANGE_REF
)
2863 innermost_dropped_array_ref
= base
;
2864 /* Otherwise drop handled components of the access. */
2867 while (handled_component_p (base
));
2869 TREE_OPERAND (lhs
, 0) = saved_lhs0
;
2871 /* Finally check if the lhs has the same address and size as the
2872 base candidate of the access. Watch out if we have dropped
2873 an array-ref that was at struct end, this means ref->ref may
2874 be outside of the TYPE_SIZE of its base. */
2875 if ((! innermost_dropped_array_ref
2876 || ! array_at_struct_end_p (innermost_dropped_array_ref
))
2878 || (((TYPE_SIZE (TREE_TYPE (lhs
))
2879 == TYPE_SIZE (TREE_TYPE (base
)))
2880 || (TYPE_SIZE (TREE_TYPE (lhs
))
2881 && TYPE_SIZE (TREE_TYPE (base
))
2882 && operand_equal_p (TYPE_SIZE (TREE_TYPE (lhs
)),
2883 TYPE_SIZE (TREE_TYPE (base
)),
2885 && operand_equal_p (lhs
, base
,
2887 | OEP_MATCH_SIDE_EFFECTS
))))
2891 /* Now look for non-literal equal bases with the restriction of
2892 handling constant offset and size. */
2893 /* For a must-alias check we need to be able to constrain
2894 the access properly. */
2895 if (!ref
->max_size_known_p ())
2897 poly_int64 size
, offset
, max_size
, ref_offset
= ref
->offset
;
2899 tree base
= get_ref_base_and_extent (lhs
, &offset
, &size
, &max_size
,
2901 /* We can get MEM[symbol: sZ, index: D.8862_1] here,
2902 so base == ref->base does not always hold. */
2903 if (base
!= ref
->base
)
2905 /* Try using points-to info. */
2906 if (same_addr_size_stores_p (base
, offset
, size
, max_size
, ref
->base
,
2907 ref
->offset
, ref
->size
, ref
->max_size
))
2910 /* If both base and ref->base are MEM_REFs, only compare the
2911 first operand, and if the second operand isn't equal constant,
2912 try to add the offsets into offset and ref_offset. */
2913 if (TREE_CODE (base
) == MEM_REF
&& TREE_CODE (ref
->base
) == MEM_REF
2914 && TREE_OPERAND (base
, 0) == TREE_OPERAND (ref
->base
, 0))
2916 if (!tree_int_cst_equal (TREE_OPERAND (base
, 1),
2917 TREE_OPERAND (ref
->base
, 1)))
2919 poly_offset_int off1
= mem_ref_offset (base
);
2920 off1
<<= LOG2_BITS_PER_UNIT
;
2922 poly_offset_int off2
= mem_ref_offset (ref
->base
);
2923 off2
<<= LOG2_BITS_PER_UNIT
;
2925 if (!off1
.to_shwi (&offset
) || !off2
.to_shwi (&ref_offset
))
2932 /* For a must-alias check we need to be able to constrain
2933 the access properly. */
2934 if (known_eq (size
, max_size
)
2935 && known_subrange_p (ref_offset
, ref
->max_size
, offset
, size
))
2939 if (is_gimple_call (stmt
))
2941 tree callee
= gimple_call_fndecl (stmt
);
2942 if (callee
!= NULL_TREE
2943 && gimple_call_builtin_p (stmt
, BUILT_IN_NORMAL
))
2944 switch (DECL_FUNCTION_CODE (callee
))
2948 tree ptr
= gimple_call_arg (stmt
, 0);
2949 tree base
= ao_ref_base (ref
);
2950 if (base
&& TREE_CODE (base
) == MEM_REF
2951 && TREE_OPERAND (base
, 0) == ptr
)
2956 case BUILT_IN_MEMCPY
:
2957 case BUILT_IN_MEMPCPY
:
2958 case BUILT_IN_MEMMOVE
:
2959 case BUILT_IN_MEMSET
:
2960 case BUILT_IN_MEMCPY_CHK
:
2961 case BUILT_IN_MEMPCPY_CHK
:
2962 case BUILT_IN_MEMMOVE_CHK
:
2963 case BUILT_IN_MEMSET_CHK
:
2964 case BUILT_IN_STRNCPY
:
2965 case BUILT_IN_STPNCPY
:
2966 case BUILT_IN_CALLOC
:
2968 /* For a must-alias check we need to be able to constrain
2969 the access properly. */
2970 if (!ref
->max_size_known_p ())
2975 /* In execution order a calloc call will never kill
2976 anything. However, DSE will (ab)use this interface
2977 to ask if a calloc call writes the same memory locations
2978 as a later assignment, memset, etc. So handle calloc
2979 in the expected way. */
2980 if (DECL_FUNCTION_CODE (callee
) == BUILT_IN_CALLOC
)
2982 tree arg0
= gimple_call_arg (stmt
, 0);
2983 tree arg1
= gimple_call_arg (stmt
, 1);
2984 if (TREE_CODE (arg0
) != INTEGER_CST
2985 || TREE_CODE (arg1
) != INTEGER_CST
)
2988 dest
= gimple_call_lhs (stmt
);
2989 len
= fold_build2 (MULT_EXPR
, TREE_TYPE (arg0
), arg0
, arg1
);
2993 dest
= gimple_call_arg (stmt
, 0);
2994 len
= gimple_call_arg (stmt
, 2);
2996 if (!poly_int_tree_p (len
))
2998 tree rbase
= ref
->base
;
2999 poly_offset_int roffset
= ref
->offset
;
3001 ao_ref_init_from_ptr_and_size (&dref
, dest
, len
);
3002 tree base
= ao_ref_base (&dref
);
3003 poly_offset_int offset
= dref
.offset
;
3004 if (!base
|| !known_size_p (dref
.size
))
3006 if (TREE_CODE (base
) == MEM_REF
)
3008 if (TREE_CODE (rbase
) != MEM_REF
)
3010 // Compare pointers.
3011 offset
+= mem_ref_offset (base
) << LOG2_BITS_PER_UNIT
;
3012 roffset
+= mem_ref_offset (rbase
) << LOG2_BITS_PER_UNIT
;
3013 base
= TREE_OPERAND (base
, 0);
3014 rbase
= TREE_OPERAND (rbase
, 0);
3017 && known_subrange_p (roffset
, ref
->max_size
, offset
,
3018 wi::to_poly_offset (len
)
3019 << LOG2_BITS_PER_UNIT
))
3024 case BUILT_IN_VA_END
:
3026 tree ptr
= gimple_call_arg (stmt
, 0);
3027 if (TREE_CODE (ptr
) == ADDR_EXPR
)
3029 tree base
= ao_ref_base (ref
);
3030 if (TREE_OPERAND (ptr
, 0) == base
)
3043 stmt_kills_ref_p (gimple
*stmt
, tree ref
)
3046 ao_ref_init (&r
, ref
);
3047 return stmt_kills_ref_p (stmt
, &r
);
3051 /* Walk the virtual use-def chain of VUSE until hitting the virtual operand
3052 TARGET or a statement clobbering the memory reference REF in which
3053 case false is returned. The walk starts with VUSE, one argument of PHI. */
3056 maybe_skip_until (gimple
*phi
, tree
&target
, basic_block target_bb
,
3057 ao_ref
*ref
, tree vuse
, bool tbaa_p
, unsigned int &limit
,
3058 bitmap
*visited
, bool abort_on_visited
,
3059 void *(*translate
)(ao_ref
*, tree
, void *, bool *),
3062 basic_block bb
= gimple_bb (phi
);
3065 *visited
= BITMAP_ALLOC (NULL
);
3067 bitmap_set_bit (*visited
, SSA_NAME_VERSION (PHI_RESULT (phi
)));
3069 /* Walk until we hit the target. */
3070 while (vuse
!= target
)
3072 gimple
*def_stmt
= SSA_NAME_DEF_STMT (vuse
);
3073 /* If we are searching for the target VUSE by walking up to
3074 TARGET_BB dominating the original PHI we are finished once
3075 we reach a default def or a definition in a block dominating
3076 that block. Update TARGET and return. */
3078 && (gimple_nop_p (def_stmt
)
3079 || dominated_by_p (CDI_DOMINATORS
,
3080 target_bb
, gimple_bb (def_stmt
))))
3086 /* Recurse for PHI nodes. */
3087 if (gimple_code (def_stmt
) == GIMPLE_PHI
)
3089 /* An already visited PHI node ends the walk successfully. */
3090 if (bitmap_bit_p (*visited
, SSA_NAME_VERSION (PHI_RESULT (def_stmt
))))
3091 return !abort_on_visited
;
3092 vuse
= get_continuation_for_phi (def_stmt
, ref
, tbaa_p
, limit
,
3093 visited
, abort_on_visited
,
3099 else if (gimple_nop_p (def_stmt
))
3103 /* A clobbering statement or the end of the IL ends it failing. */
3104 if ((int)limit
<= 0)
3107 if (stmt_may_clobber_ref_p_1 (def_stmt
, ref
, tbaa_p
))
3109 bool disambiguate_only
= true;
3111 && (*translate
) (ref
, vuse
, data
, &disambiguate_only
) == NULL
)
3117 /* If we reach a new basic-block see if we already skipped it
3118 in a previous walk that ended successfully. */
3119 if (gimple_bb (def_stmt
) != bb
)
3121 if (!bitmap_set_bit (*visited
, SSA_NAME_VERSION (vuse
)))
3122 return !abort_on_visited
;
3123 bb
= gimple_bb (def_stmt
);
3125 vuse
= gimple_vuse (def_stmt
);
3131 /* Starting from a PHI node for the virtual operand of the memory reference
3132 REF find a continuation virtual operand that allows to continue walking
3133 statements dominating PHI skipping only statements that cannot possibly
3134 clobber REF. Decrements LIMIT for each alias disambiguation done
3135 and aborts the walk, returning NULL_TREE if it reaches zero.
3136 Returns NULL_TREE if no suitable virtual operand can be found. */
3139 get_continuation_for_phi (gimple
*phi
, ao_ref
*ref
, bool tbaa_p
,
3140 unsigned int &limit
, bitmap
*visited
,
3141 bool abort_on_visited
,
3142 void *(*translate
)(ao_ref
*, tree
, void *, bool *),
3145 unsigned nargs
= gimple_phi_num_args (phi
);
3147 /* Through a single-argument PHI we can simply look through. */
3149 return PHI_ARG_DEF (phi
, 0);
3151 /* For two or more arguments try to pairwise skip non-aliasing code
3152 until we hit the phi argument definition that dominates the other one. */
3153 basic_block phi_bb
= gimple_bb (phi
);
3157 /* Find a candidate for the virtual operand which definition
3158 dominates those of all others. */
3159 /* First look if any of the args themselves satisfy this. */
3160 for (i
= 0; i
< nargs
; ++i
)
3162 arg0
= PHI_ARG_DEF (phi
, i
);
3163 if (SSA_NAME_IS_DEFAULT_DEF (arg0
))
3165 basic_block def_bb
= gimple_bb (SSA_NAME_DEF_STMT (arg0
));
3166 if (def_bb
!= phi_bb
3167 && dominated_by_p (CDI_DOMINATORS
, phi_bb
, def_bb
))
3171 /* If not, look if we can reach such candidate by walking defs
3172 until we hit the immediate dominator. maybe_skip_until will
3174 basic_block dom
= get_immediate_dominator (CDI_DOMINATORS
, phi_bb
);
3176 /* Then check against the (to be) found candidate. */
3177 for (i
= 0; i
< nargs
; ++i
)
3179 arg1
= PHI_ARG_DEF (phi
, i
);
3182 else if (! maybe_skip_until (phi
, arg0
, dom
, ref
, arg1
, tbaa_p
,
3185 /* Do not translate when walking over
3189 gimple_bb (SSA_NAME_DEF_STMT (arg1
)),
3191 ? NULL
: translate
, data
))
3198 /* Based on the memory reference REF and its virtual use VUSE call
3199 WALKER for each virtual use that is equivalent to VUSE, including VUSE
3200 itself. That is, for each virtual use for which its defining statement
3201 does not clobber REF.
3203 WALKER is called with REF, the current virtual use and DATA. If
3204 WALKER returns non-NULL the walk stops and its result is returned.
3205 At the end of a non-successful walk NULL is returned.
3207 TRANSLATE if non-NULL is called with a pointer to REF, the virtual
3208 use which definition is a statement that may clobber REF and DATA.
3209 If TRANSLATE returns (void *)-1 the walk stops and NULL is returned.
3210 If TRANSLATE returns non-NULL the walk stops and its result is returned.
3211 If TRANSLATE returns NULL the walk continues and TRANSLATE is supposed
3212 to adjust REF and *DATA to make that valid.
3214 VALUEIZE if non-NULL is called with the next VUSE that is considered
3215 and return value is substituted for that. This can be used to
3216 implement optimistic value-numbering for example. Note that the
3217 VUSE argument is assumed to be valueized already.
3219 LIMIT specifies the number of alias queries we are allowed to do,
3220 the walk stops when it reaches zero and NULL is returned. LIMIT
3221 is decremented by the number of alias queries (plus adjustments
3222 done by the callbacks) upon return.
3224 TODO: Cache the vector of equivalent vuses per ref, vuse pair. */
3227 walk_non_aliased_vuses (ao_ref
*ref
, tree vuse
, bool tbaa_p
,
3228 void *(*walker
)(ao_ref
*, tree
, void *),
3229 void *(*translate
)(ao_ref
*, tree
, void *, bool *),
3230 tree (*valueize
)(tree
),
3231 unsigned &limit
, void *data
)
3233 bitmap visited
= NULL
;
3235 bool translated
= false;
3237 timevar_push (TV_ALIAS_STMT_WALK
);
3243 /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */
3244 res
= (*walker
) (ref
, vuse
, data
);
3246 if (res
== (void *)-1)
3251 /* Lookup succeeded. */
3252 else if (res
!= NULL
)
3257 vuse
= valueize (vuse
);
3264 def_stmt
= SSA_NAME_DEF_STMT (vuse
);
3265 if (gimple_nop_p (def_stmt
))
3267 else if (gimple_code (def_stmt
) == GIMPLE_PHI
)
3268 vuse
= get_continuation_for_phi (def_stmt
, ref
, tbaa_p
, limit
,
3269 &visited
, translated
, translate
, data
);
3272 if ((int)limit
<= 0)
3278 if (stmt_may_clobber_ref_p_1 (def_stmt
, ref
, tbaa_p
))
3282 bool disambiguate_only
= false;
3283 res
= (*translate
) (ref
, vuse
, data
, &disambiguate_only
);
3284 /* Failed lookup and translation. */
3285 if (res
== (void *)-1)
3290 /* Lookup succeeded. */
3291 else if (res
!= NULL
)
3293 /* Translation succeeded, continue walking. */
3294 translated
= translated
|| !disambiguate_only
;
3296 vuse
= gimple_vuse (def_stmt
);
3302 BITMAP_FREE (visited
);
3304 timevar_pop (TV_ALIAS_STMT_WALK
);
3310 /* Based on the memory reference REF call WALKER for each vdef which
3311 defining statement may clobber REF, starting with VDEF. If REF
3312 is NULL_TREE, each defining statement is visited.
3314 WALKER is called with REF, the current vdef and DATA. If WALKER
3315 returns true the walk is stopped, otherwise it continues.
3317 If function entry is reached, FUNCTION_ENTRY_REACHED is set to true.
3318 The pointer may be NULL and then we do not track this information.
3320 At PHI nodes walk_aliased_vdefs forks into one walk for reach
3321 PHI argument (but only one walk continues on merge points), the
3322 return value is true if any of the walks was successful.
3324 The function returns the number of statements walked or -1 if
3325 LIMIT stmts were walked and the walk was aborted at this point.
3326 If LIMIT is zero the walk is not aborted. */
3329 walk_aliased_vdefs_1 (ao_ref
*ref
, tree vdef
,
3330 bool (*walker
)(ao_ref
*, tree
, void *), void *data
,
3331 bitmap
*visited
, unsigned int cnt
,
3332 bool *function_entry_reached
, unsigned limit
)
3336 gimple
*def_stmt
= SSA_NAME_DEF_STMT (vdef
);
3339 && !bitmap_set_bit (*visited
, SSA_NAME_VERSION (vdef
)))
3342 if (gimple_nop_p (def_stmt
))
3344 if (function_entry_reached
)
3345 *function_entry_reached
= true;
3348 else if (gimple_code (def_stmt
) == GIMPLE_PHI
)
3352 *visited
= BITMAP_ALLOC (NULL
);
3353 for (i
= 0; i
< gimple_phi_num_args (def_stmt
); ++i
)
3355 int res
= walk_aliased_vdefs_1 (ref
,
3356 gimple_phi_arg_def (def_stmt
, i
),
3357 walker
, data
, visited
, cnt
,
3358 function_entry_reached
, limit
);
3366 /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */
3371 || stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
3372 && (*walker
) (ref
, vdef
, data
))
3375 vdef
= gimple_vuse (def_stmt
);
3381 walk_aliased_vdefs (ao_ref
*ref
, tree vdef
,
3382 bool (*walker
)(ao_ref
*, tree
, void *), void *data
,
3384 bool *function_entry_reached
, unsigned int limit
)
3386 bitmap local_visited
= NULL
;
3389 timevar_push (TV_ALIAS_STMT_WALK
);
3391 if (function_entry_reached
)
3392 *function_entry_reached
= false;
3394 ret
= walk_aliased_vdefs_1 (ref
, vdef
, walker
, data
,
3395 visited
? visited
: &local_visited
, 0,
3396 function_entry_reached
, limit
);
3398 BITMAP_FREE (local_visited
);
3400 timevar_pop (TV_ALIAS_STMT_WALK
);