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. */
91 /* Query statistics for the different low-level disambiguators.
92 A high-level query may trigger multiple of them. */
95 unsigned HOST_WIDE_INT refs_may_alias_p_may_alias
;
96 unsigned HOST_WIDE_INT refs_may_alias_p_no_alias
;
97 unsigned HOST_WIDE_INT ref_maybe_used_by_call_p_may_alias
;
98 unsigned HOST_WIDE_INT ref_maybe_used_by_call_p_no_alias
;
99 unsigned HOST_WIDE_INT call_may_clobber_ref_p_may_alias
;
100 unsigned HOST_WIDE_INT call_may_clobber_ref_p_no_alias
;
101 unsigned HOST_WIDE_INT aliasing_component_refs_p_may_alias
;
102 unsigned HOST_WIDE_INT aliasing_component_refs_p_no_alias
;
103 unsigned HOST_WIDE_INT nonoverlapping_component_refs_p_may_alias
;
104 unsigned HOST_WIDE_INT nonoverlapping_component_refs_p_no_alias
;
105 unsigned HOST_WIDE_INT nonoverlapping_component_refs_of_decl_p_may_alias
;
106 unsigned HOST_WIDE_INT nonoverlapping_component_refs_of_decl_p_no_alias
;
110 dump_alias_stats (FILE *s
)
112 fprintf (s
, "\nAlias oracle query stats:\n");
113 fprintf (s
, " refs_may_alias_p: "
114 HOST_WIDE_INT_PRINT_DEC
" disambiguations, "
115 HOST_WIDE_INT_PRINT_DEC
" queries\n",
116 alias_stats
.refs_may_alias_p_no_alias
,
117 alias_stats
.refs_may_alias_p_no_alias
118 + alias_stats
.refs_may_alias_p_may_alias
);
119 fprintf (s
, " ref_maybe_used_by_call_p: "
120 HOST_WIDE_INT_PRINT_DEC
" disambiguations, "
121 HOST_WIDE_INT_PRINT_DEC
" queries\n",
122 alias_stats
.ref_maybe_used_by_call_p_no_alias
,
123 alias_stats
.refs_may_alias_p_no_alias
124 + alias_stats
.ref_maybe_used_by_call_p_may_alias
);
125 fprintf (s
, " call_may_clobber_ref_p: "
126 HOST_WIDE_INT_PRINT_DEC
" disambiguations, "
127 HOST_WIDE_INT_PRINT_DEC
" queries\n",
128 alias_stats
.call_may_clobber_ref_p_no_alias
,
129 alias_stats
.call_may_clobber_ref_p_no_alias
130 + alias_stats
.call_may_clobber_ref_p_may_alias
);
131 fprintf (s
, " nonoverlapping_component_refs_p: "
132 HOST_WIDE_INT_PRINT_DEC
" disambiguations, "
133 HOST_WIDE_INT_PRINT_DEC
" queries\n",
134 alias_stats
.nonoverlapping_component_refs_p_no_alias
,
135 alias_stats
.nonoverlapping_component_refs_p_no_alias
136 + alias_stats
.nonoverlapping_component_refs_p_may_alias
);
137 fprintf (s
, " nonoverlapping_component_refs_of_decl_p: "
138 HOST_WIDE_INT_PRINT_DEC
" disambiguations, "
139 HOST_WIDE_INT_PRINT_DEC
" queries\n",
140 alias_stats
.nonoverlapping_component_refs_of_decl_p_no_alias
,
141 alias_stats
.nonoverlapping_component_refs_of_decl_p_no_alias
142 + alias_stats
.nonoverlapping_component_refs_of_decl_p_may_alias
);
143 fprintf (s
, " aliasing_component_refs_p: "
144 HOST_WIDE_INT_PRINT_DEC
" disambiguations, "
145 HOST_WIDE_INT_PRINT_DEC
" queries\n",
146 alias_stats
.aliasing_component_refs_p_no_alias
,
147 alias_stats
.aliasing_component_refs_p_no_alias
148 + alias_stats
.aliasing_component_refs_p_may_alias
);
149 dump_alias_stats_in_alias_c (s
);
153 /* Return true, if dereferencing PTR may alias with a global variable. */
156 ptr_deref_may_alias_global_p (tree ptr
)
158 struct ptr_info_def
*pi
;
160 /* If we end up with a pointer constant here that may point
162 if (TREE_CODE (ptr
) != SSA_NAME
)
165 pi
= SSA_NAME_PTR_INFO (ptr
);
167 /* If we do not have points-to information for this variable,
172 /* ??? This does not use TBAA to prune globals ptr may not access. */
173 return pt_solution_includes_global (&pi
->pt
);
176 /* Return true if dereferencing PTR may alias DECL.
177 The caller is responsible for applying TBAA to see if PTR
178 may access DECL at all. */
181 ptr_deref_may_alias_decl_p (tree ptr
, tree decl
)
183 struct ptr_info_def
*pi
;
185 /* Conversions are irrelevant for points-to information and
186 data-dependence analysis can feed us those. */
189 /* Anything we do not explicilty handle aliases. */
190 if ((TREE_CODE (ptr
) != SSA_NAME
191 && TREE_CODE (ptr
) != ADDR_EXPR
192 && TREE_CODE (ptr
) != POINTER_PLUS_EXPR
)
193 || !POINTER_TYPE_P (TREE_TYPE (ptr
))
195 && TREE_CODE (decl
) != PARM_DECL
196 && TREE_CODE (decl
) != RESULT_DECL
))
199 /* Disregard pointer offsetting. */
200 if (TREE_CODE (ptr
) == POINTER_PLUS_EXPR
)
204 ptr
= TREE_OPERAND (ptr
, 0);
206 while (TREE_CODE (ptr
) == POINTER_PLUS_EXPR
);
207 return ptr_deref_may_alias_decl_p (ptr
, decl
);
210 /* ADDR_EXPR pointers either just offset another pointer or directly
211 specify the pointed-to set. */
212 if (TREE_CODE (ptr
) == ADDR_EXPR
)
214 tree base
= get_base_address (TREE_OPERAND (ptr
, 0));
216 && (TREE_CODE (base
) == MEM_REF
217 || TREE_CODE (base
) == TARGET_MEM_REF
))
218 ptr
= TREE_OPERAND (base
, 0);
221 return compare_base_decls (base
, decl
) != 0;
223 && CONSTANT_CLASS_P (base
))
229 /* Non-aliased variables cannot be pointed to. */
230 if (!may_be_aliased (decl
))
233 /* If we do not have useful points-to information for this pointer
234 we cannot disambiguate anything else. */
235 pi
= SSA_NAME_PTR_INFO (ptr
);
239 return pt_solution_includes (&pi
->pt
, decl
);
242 /* Return true if dereferenced PTR1 and PTR2 may alias.
243 The caller is responsible for applying TBAA to see if accesses
244 through PTR1 and PTR2 may conflict at all. */
247 ptr_derefs_may_alias_p (tree ptr1
, tree ptr2
)
249 struct ptr_info_def
*pi1
, *pi2
;
251 /* Conversions are irrelevant for points-to information and
252 data-dependence analysis can feed us those. */
256 /* Disregard pointer offsetting. */
257 if (TREE_CODE (ptr1
) == POINTER_PLUS_EXPR
)
261 ptr1
= TREE_OPERAND (ptr1
, 0);
263 while (TREE_CODE (ptr1
) == POINTER_PLUS_EXPR
);
264 return ptr_derefs_may_alias_p (ptr1
, ptr2
);
266 if (TREE_CODE (ptr2
) == POINTER_PLUS_EXPR
)
270 ptr2
= TREE_OPERAND (ptr2
, 0);
272 while (TREE_CODE (ptr2
) == POINTER_PLUS_EXPR
);
273 return ptr_derefs_may_alias_p (ptr1
, ptr2
);
276 /* ADDR_EXPR pointers either just offset another pointer or directly
277 specify the pointed-to set. */
278 if (TREE_CODE (ptr1
) == ADDR_EXPR
)
280 tree base
= get_base_address (TREE_OPERAND (ptr1
, 0));
282 && (TREE_CODE (base
) == MEM_REF
283 || TREE_CODE (base
) == TARGET_MEM_REF
))
284 return ptr_derefs_may_alias_p (TREE_OPERAND (base
, 0), ptr2
);
287 return ptr_deref_may_alias_decl_p (ptr2
, base
);
291 if (TREE_CODE (ptr2
) == ADDR_EXPR
)
293 tree base
= get_base_address (TREE_OPERAND (ptr2
, 0));
295 && (TREE_CODE (base
) == MEM_REF
296 || TREE_CODE (base
) == TARGET_MEM_REF
))
297 return ptr_derefs_may_alias_p (ptr1
, TREE_OPERAND (base
, 0));
300 return ptr_deref_may_alias_decl_p (ptr1
, base
);
305 /* From here we require SSA name pointers. Anything else aliases. */
306 if (TREE_CODE (ptr1
) != SSA_NAME
307 || TREE_CODE (ptr2
) != SSA_NAME
308 || !POINTER_TYPE_P (TREE_TYPE (ptr1
))
309 || !POINTER_TYPE_P (TREE_TYPE (ptr2
)))
312 /* We may end up with two empty points-to solutions for two same pointers.
313 In this case we still want to say both pointers alias, so shortcut
318 /* If we do not have useful points-to information for either pointer
319 we cannot disambiguate anything else. */
320 pi1
= SSA_NAME_PTR_INFO (ptr1
);
321 pi2
= SSA_NAME_PTR_INFO (ptr2
);
325 /* ??? This does not use TBAA to prune decls from the intersection
326 that not both pointers may access. */
327 return pt_solutions_intersect (&pi1
->pt
, &pi2
->pt
);
330 /* Return true if dereferencing PTR may alias *REF.
331 The caller is responsible for applying TBAA to see if PTR
332 may access *REF at all. */
335 ptr_deref_may_alias_ref_p_1 (tree ptr
, ao_ref
*ref
)
337 tree base
= ao_ref_base (ref
);
339 if (TREE_CODE (base
) == MEM_REF
340 || TREE_CODE (base
) == TARGET_MEM_REF
)
341 return ptr_derefs_may_alias_p (ptr
, TREE_OPERAND (base
, 0));
342 else if (DECL_P (base
))
343 return ptr_deref_may_alias_decl_p (ptr
, base
);
348 /* Returns true if PTR1 and PTR2 compare unequal because of points-to. */
351 ptrs_compare_unequal (tree ptr1
, tree ptr2
)
353 /* First resolve the pointers down to a SSA name pointer base or
354 a VAR_DECL, PARM_DECL or RESULT_DECL. This explicitely does
355 not yet try to handle LABEL_DECLs, FUNCTION_DECLs, CONST_DECLs
356 or STRING_CSTs which needs points-to adjustments to track them
357 in the points-to sets. */
358 tree obj1
= NULL_TREE
;
359 tree obj2
= NULL_TREE
;
360 if (TREE_CODE (ptr1
) == ADDR_EXPR
)
362 tree tem
= get_base_address (TREE_OPERAND (ptr1
, 0));
366 || TREE_CODE (tem
) == PARM_DECL
367 || TREE_CODE (tem
) == RESULT_DECL
)
369 else if (TREE_CODE (tem
) == MEM_REF
)
370 ptr1
= TREE_OPERAND (tem
, 0);
372 if (TREE_CODE (ptr2
) == ADDR_EXPR
)
374 tree tem
= get_base_address (TREE_OPERAND (ptr2
, 0));
378 || TREE_CODE (tem
) == PARM_DECL
379 || TREE_CODE (tem
) == RESULT_DECL
)
381 else if (TREE_CODE (tem
) == MEM_REF
)
382 ptr2
= TREE_OPERAND (tem
, 0);
385 /* Canonicalize ptr vs. object. */
386 if (TREE_CODE (ptr1
) == SSA_NAME
&& obj2
)
388 std::swap (ptr1
, ptr2
);
389 std::swap (obj1
, obj2
);
393 /* Other code handles this correctly, no need to duplicate it here. */;
394 else if (obj1
&& TREE_CODE (ptr2
) == SSA_NAME
)
396 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (ptr2
);
397 /* We may not use restrict to optimize pointer comparisons.
398 See PR71062. So we have to assume that restrict-pointed-to
399 may be in fact obj1. */
401 || pi
->pt
.vars_contains_restrict
402 || pi
->pt
.vars_contains_interposable
)
405 && (TREE_STATIC (obj1
) || DECL_EXTERNAL (obj1
)))
407 varpool_node
*node
= varpool_node::get (obj1
);
408 /* If obj1 may bind to NULL give up (see below). */
410 || ! node
->nonzero_address ()
411 || ! decl_binds_to_current_def_p (obj1
))
414 return !pt_solution_includes (&pi
->pt
, obj1
);
417 /* ??? We'd like to handle ptr1 != NULL and ptr1 != ptr2
418 but those require pt.null to be conservatively correct. */
423 /* Returns whether reference REF to BASE may refer to global memory. */
426 ref_may_alias_global_p_1 (tree base
)
429 return is_global_var (base
);
430 else if (TREE_CODE (base
) == MEM_REF
431 || TREE_CODE (base
) == TARGET_MEM_REF
)
432 return ptr_deref_may_alias_global_p (TREE_OPERAND (base
, 0));
437 ref_may_alias_global_p (ao_ref
*ref
)
439 tree base
= ao_ref_base (ref
);
440 return ref_may_alias_global_p_1 (base
);
444 ref_may_alias_global_p (tree ref
)
446 tree base
= get_base_address (ref
);
447 return ref_may_alias_global_p_1 (base
);
450 /* Return true whether STMT may clobber global memory. */
453 stmt_may_clobber_global_p (gimple
*stmt
)
457 if (!gimple_vdef (stmt
))
460 /* ??? We can ask the oracle whether an artificial pointer
461 dereference with a pointer with points-to information covering
462 all global memory (what about non-address taken memory?) maybe
463 clobbered by this call. As there is at the moment no convenient
464 way of doing that without generating garbage do some manual
466 ??? We could make a NULL ao_ref argument to the various
467 predicates special, meaning any global memory. */
469 switch (gimple_code (stmt
))
472 lhs
= gimple_assign_lhs (stmt
);
473 return (TREE_CODE (lhs
) != SSA_NAME
474 && ref_may_alias_global_p (lhs
));
483 /* Dump alias information on FILE. */
486 dump_alias_info (FILE *file
)
491 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
494 fprintf (file
, "\n\nAlias information for %s\n\n", funcname
);
496 fprintf (file
, "Aliased symbols\n\n");
498 FOR_EACH_LOCAL_DECL (cfun
, i
, var
)
500 if (may_be_aliased (var
))
501 dump_variable (file
, var
);
504 fprintf (file
, "\nCall clobber information\n");
506 fprintf (file
, "\nESCAPED");
507 dump_points_to_solution (file
, &cfun
->gimple_df
->escaped
);
509 fprintf (file
, "\n\nFlow-insensitive points-to information\n\n");
511 FOR_EACH_SSA_NAME (i
, ptr
, cfun
)
513 struct ptr_info_def
*pi
;
515 if (!POINTER_TYPE_P (TREE_TYPE (ptr
))
516 || SSA_NAME_IN_FREE_LIST (ptr
))
519 pi
= SSA_NAME_PTR_INFO (ptr
);
521 dump_points_to_info_for (file
, ptr
);
524 fprintf (file
, "\n");
528 /* Dump alias information on stderr. */
531 debug_alias_info (void)
533 dump_alias_info (stderr
);
537 /* Dump the points-to set *PT into FILE. */
540 dump_points_to_solution (FILE *file
, struct pt_solution
*pt
)
543 fprintf (file
, ", points-to anything");
546 fprintf (file
, ", points-to non-local");
549 fprintf (file
, ", points-to escaped");
552 fprintf (file
, ", points-to unit escaped");
555 fprintf (file
, ", points-to NULL");
559 fprintf (file
, ", points-to vars: ");
560 dump_decl_set (file
, pt
->vars
);
561 if (pt
->vars_contains_nonlocal
562 || pt
->vars_contains_escaped
563 || pt
->vars_contains_escaped_heap
564 || pt
->vars_contains_restrict
)
566 const char *comma
= "";
567 fprintf (file
, " (");
568 if (pt
->vars_contains_nonlocal
)
570 fprintf (file
, "nonlocal");
573 if (pt
->vars_contains_escaped
)
575 fprintf (file
, "%sescaped", comma
);
578 if (pt
->vars_contains_escaped_heap
)
580 fprintf (file
, "%sescaped heap", comma
);
583 if (pt
->vars_contains_restrict
)
585 fprintf (file
, "%srestrict", comma
);
588 if (pt
->vars_contains_interposable
)
589 fprintf (file
, "%sinterposable", comma
);
596 /* Unified dump function for pt_solution. */
599 debug (pt_solution
&ref
)
601 dump_points_to_solution (stderr
, &ref
);
605 debug (pt_solution
*ptr
)
610 fprintf (stderr
, "<nil>\n");
614 /* Dump points-to information for SSA_NAME PTR into FILE. */
617 dump_points_to_info_for (FILE *file
, tree ptr
)
619 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (ptr
);
621 print_generic_expr (file
, ptr
, dump_flags
);
624 dump_points_to_solution (file
, &pi
->pt
);
626 fprintf (file
, ", points-to anything");
628 fprintf (file
, "\n");
632 /* Dump points-to information for VAR into stderr. */
635 debug_points_to_info_for (tree var
)
637 dump_points_to_info_for (stderr
, var
);
641 /* Initializes the alias-oracle reference representation *R from REF. */
644 ao_ref_init (ao_ref
*r
, tree ref
)
651 r
->ref_alias_set
= -1;
652 r
->base_alias_set
= -1;
653 r
->volatile_p
= ref
? TREE_THIS_VOLATILE (ref
) : false;
656 /* Returns the base object of the memory reference *REF. */
659 ao_ref_base (ao_ref
*ref
)
665 ref
->base
= get_ref_base_and_extent (ref
->ref
, &ref
->offset
, &ref
->size
,
666 &ref
->max_size
, &reverse
);
670 /* Returns the base object alias set of the memory reference *REF. */
673 ao_ref_base_alias_set (ao_ref
*ref
)
676 if (ref
->base_alias_set
!= -1)
677 return ref
->base_alias_set
;
681 while (handled_component_p (base_ref
))
682 base_ref
= TREE_OPERAND (base_ref
, 0);
683 ref
->base_alias_set
= get_alias_set (base_ref
);
684 return ref
->base_alias_set
;
687 /* Returns the reference alias set of the memory reference *REF. */
690 ao_ref_alias_set (ao_ref
*ref
)
692 if (ref
->ref_alias_set
!= -1)
693 return ref
->ref_alias_set
;
694 ref
->ref_alias_set
= get_alias_set (ref
->ref
);
695 return ref
->ref_alias_set
;
698 /* Init an alias-oracle reference representation from a gimple pointer
699 PTR and a gimple size SIZE in bytes. If SIZE is NULL_TREE then the
700 size is assumed to be unknown. The access is assumed to be only
701 to or after of the pointer target, not before it. */
704 ao_ref_init_from_ptr_and_size (ao_ref
*ref
, tree ptr
, tree size
)
706 poly_int64 t
, size_hwi
, extra_offset
= 0;
707 ref
->ref
= NULL_TREE
;
708 if (TREE_CODE (ptr
) == SSA_NAME
)
710 gimple
*stmt
= SSA_NAME_DEF_STMT (ptr
);
711 if (gimple_assign_single_p (stmt
)
712 && gimple_assign_rhs_code (stmt
) == ADDR_EXPR
)
713 ptr
= gimple_assign_rhs1 (stmt
);
714 else if (is_gimple_assign (stmt
)
715 && gimple_assign_rhs_code (stmt
) == POINTER_PLUS_EXPR
716 && ptrdiff_tree_p (gimple_assign_rhs2 (stmt
), &extra_offset
))
718 ptr
= gimple_assign_rhs1 (stmt
);
719 extra_offset
*= BITS_PER_UNIT
;
723 if (TREE_CODE (ptr
) == ADDR_EXPR
)
725 ref
->base
= get_addr_base_and_unit_offset (TREE_OPERAND (ptr
, 0), &t
);
727 ref
->offset
= BITS_PER_UNIT
* t
;
732 ref
->base
= get_base_address (TREE_OPERAND (ptr
, 0));
737 gcc_assert (POINTER_TYPE_P (TREE_TYPE (ptr
)));
738 ref
->base
= build2 (MEM_REF
, char_type_node
,
739 ptr
, null_pointer_node
);
742 ref
->offset
+= extra_offset
;
744 && poly_int_tree_p (size
, &size_hwi
)
745 && coeffs_in_range_p (size_hwi
, 0, HOST_WIDE_INT_MAX
/ BITS_PER_UNIT
))
746 ref
->max_size
= ref
->size
= size_hwi
* BITS_PER_UNIT
;
748 ref
->max_size
= ref
->size
= -1;
749 ref
->ref_alias_set
= 0;
750 ref
->base_alias_set
= 0;
751 ref
->volatile_p
= false;
754 /* S1 and S2 are TYPE_SIZE or DECL_SIZE. Compare them:
757 Return 0 if equal or incomparable. */
760 compare_sizes (tree s1
, tree s2
)
768 if (!poly_int_tree_p (s1
, &size1
) || !poly_int_tree_p (s2
, &size2
))
770 if (known_lt (size1
, size2
))
772 if (known_lt (size2
, size1
))
777 /* Compare TYPE1 and TYPE2 by its size.
778 Return -1 if size of TYPE1 < size of TYPE2
779 Return 1 if size of TYPE1 > size of TYPE2
780 Return 0 if types are of equal sizes or we can not compare them. */
783 compare_type_sizes (tree type1
, tree type2
)
785 /* Be conservative for arrays and vectors. We want to support partial
786 overlap on int[3] and int[3] as tested in gcc.dg/torture/alias-2.c. */
787 while (TREE_CODE (type1
) == ARRAY_TYPE
788 || TREE_CODE (type1
) == VECTOR_TYPE
)
789 type1
= TREE_TYPE (type1
);
790 while (TREE_CODE (type2
) == ARRAY_TYPE
791 || TREE_CODE (type2
) == VECTOR_TYPE
)
792 type2
= TREE_TYPE (type2
);
793 return compare_sizes (TYPE_SIZE (type1
), TYPE_SIZE (type2
));
796 /* Return 1 if TYPE1 and TYPE2 are to be considered equivalent for the
797 purpose of TBAA. Return 0 if they are distinct and -1 if we cannot
801 same_type_for_tbaa (tree type1
, tree type2
)
803 type1
= TYPE_MAIN_VARIANT (type1
);
804 type2
= TYPE_MAIN_VARIANT (type2
);
806 /* Handle the most common case first. */
810 /* If we would have to do structural comparison bail out. */
811 if (TYPE_STRUCTURAL_EQUALITY_P (type1
)
812 || TYPE_STRUCTURAL_EQUALITY_P (type2
))
815 /* Compare the canonical types. */
816 if (TYPE_CANONICAL (type1
) == TYPE_CANONICAL (type2
))
819 /* ??? Array types are not properly unified in all cases as we have
820 spurious changes in the index types for example. Removing this
821 causes all sorts of problems with the Fortran frontend. */
822 if (TREE_CODE (type1
) == ARRAY_TYPE
823 && TREE_CODE (type2
) == ARRAY_TYPE
)
826 /* ??? In Ada, an lvalue of an unconstrained type can be used to access an
827 object of one of its constrained subtypes, e.g. when a function with an
828 unconstrained parameter passed by reference is called on an object and
829 inlined. But, even in the case of a fixed size, type and subtypes are
830 not equivalent enough as to share the same TYPE_CANONICAL, since this
831 would mean that conversions between them are useless, whereas they are
832 not (e.g. type and subtypes can have different modes). So, in the end,
833 they are only guaranteed to have the same alias set. */
834 if (get_alias_set (type1
) == get_alias_set (type2
))
837 /* The types are known to be not equal. */
841 /* Return true if TYPE is a composite type (i.e. we may apply one of handled
842 components on it). */
845 type_has_components_p (tree type
)
847 return AGGREGATE_TYPE_P (type
) || VECTOR_TYPE_P (type
)
848 || TREE_CODE (type
) == COMPLEX_TYPE
;
851 /* Determine if the two component references REF1 and REF2 which are
852 based on access types TYPE1 and TYPE2 and of which at least one is based
853 on an indirect reference may alias.
854 REF1_ALIAS_SET, BASE1_ALIAS_SET, REF2_ALIAS_SET and BASE2_ALIAS_SET
855 are the respective alias sets. */
858 aliasing_component_refs_p (tree ref1
,
859 alias_set_type ref1_alias_set
,
860 alias_set_type base1_alias_set
,
861 poly_int64 offset1
, poly_int64 max_size1
,
863 alias_set_type ref2_alias_set
,
864 alias_set_type base2_alias_set
,
865 poly_int64 offset2
, poly_int64 max_size2
)
867 /* If one reference is a component references through pointers try to find a
868 common base and apply offset based disambiguation. This handles
870 struct A { int i; int j; } *q;
871 struct B { struct A a; int k; } *p;
872 disambiguating q->i and p->a.j. */
875 int same_p1
= 0, same_p2
= 0;
876 bool maybe_match
= false;
877 tree end_struct_ref1
= NULL
, end_struct_ref2
= NULL
;
879 /* Choose bases and base types to search for. */
881 while (handled_component_p (base1
))
883 /* Generally access paths are monotous in the size of object. The
884 exception are trailing arrays of structures. I.e.
885 struct a {int array[0];};
887 struct a {int array1[0]; int array[];};
888 Such struct has size 0 but accesses to a.array may have non-zero size.
889 In this case the size of TREE_TYPE (base1) is smaller than
890 size of TREE_TYPE (TREE_OPERNAD (base1, 0)).
892 Because we compare sizes of arrays just by sizes of their elements,
893 we only need to care about zero sized array fields here. */
894 if (TREE_CODE (base1
) == COMPONENT_REF
895 && TREE_CODE (TREE_TYPE (TREE_OPERAND (base1
, 1))) == ARRAY_TYPE
896 && (!TYPE_SIZE (TREE_TYPE (TREE_OPERAND (base1
, 1)))
897 || integer_zerop (TYPE_SIZE (TREE_TYPE (TREE_OPERAND (base1
, 1)))))
898 && array_at_struct_end_p (base1
))
900 gcc_checking_assert (!end_struct_ref1
);
901 end_struct_ref1
= base1
;
903 if (TREE_CODE (base1
) == VIEW_CONVERT_EXPR
904 || TREE_CODE (base1
) == BIT_FIELD_REF
)
905 ref1
= TREE_OPERAND (base1
, 0);
906 base1
= TREE_OPERAND (base1
, 0);
908 type1
= TREE_TYPE (base1
);
910 while (handled_component_p (base2
))
912 if (TREE_CODE (base2
) == COMPONENT_REF
913 && TREE_CODE (TREE_TYPE (TREE_OPERAND (base2
, 1))) == ARRAY_TYPE
914 && (!TYPE_SIZE (TREE_TYPE (TREE_OPERAND (base2
, 1)))
915 || integer_zerop (TYPE_SIZE (TREE_TYPE (TREE_OPERAND (base2
, 1)))))
916 && array_at_struct_end_p (base2
))
918 gcc_checking_assert (!end_struct_ref2
);
919 end_struct_ref2
= base2
;
921 if (TREE_CODE (base2
) == VIEW_CONVERT_EXPR
922 || TREE_CODE (base2
) == BIT_FIELD_REF
)
923 ref2
= TREE_OPERAND (base2
, 0);
924 base2
= TREE_OPERAND (base2
, 0);
926 type2
= TREE_TYPE (base2
);
928 /* Now search for the type1 in the access path of ref2. This
929 would be a common base for doing offset based disambiguation on.
930 This however only makes sense if type2 is big enough to hold type1. */
931 int cmp_outer
= compare_type_sizes (type2
, type1
);
933 /* If type2 is big enough to contain type1 walk its access path.
934 We also need to care of arrays at the end of structs that may extend
935 beyond the end of structure. */
938 && compare_type_sizes (TREE_TYPE (end_struct_ref2
), type1
) >= 0))
943 /* We walk from inner type to the outer types. If type we see is
944 already too large to be part of type1, terminate the search. */
945 int cmp
= compare_type_sizes (type1
, TREE_TYPE (ref
));
949 || compare_type_sizes (TREE_TYPE (end_struct_ref1
),
950 TREE_TYPE (ref
)) < 0))
952 /* If types may be of same size, see if we can decide about their
956 same_p2
= same_type_for_tbaa (TREE_TYPE (ref
), type1
);
959 /* In case we can't decide whether types are same try to
960 continue looking for the exact match.
961 Remember however that we possibly saw a match
962 to bypass the access path continuations tests we do later. */
966 if (!handled_component_p (ref
))
968 ref
= TREE_OPERAND (ref
, 0);
972 poly_int64 offadj
, sztmp
, msztmp
;
975 /* We assume that arrays can overlap by multiple of their elements
976 size as tested in gcc.dg/torture/alias-2.c.
977 This partial overlap happen only when both arrays are bases of
978 the access and not contained within another component ref.
979 To be safe we also assume partial overlap for VLAs. */
980 if (TREE_CODE (TREE_TYPE (base1
)) == ARRAY_TYPE
981 && (!TYPE_SIZE (TREE_TYPE (base1
))
982 || TREE_CODE (TYPE_SIZE (TREE_TYPE (base1
))) != INTEGER_CST
985 ++alias_stats
.aliasing_component_refs_p_may_alias
;
989 get_ref_base_and_extent (ref
, &offadj
, &sztmp
, &msztmp
, &reverse
);
991 get_ref_base_and_extent (base1
, &offadj
, &sztmp
, &msztmp
, &reverse
);
993 if (ranges_maybe_overlap_p (offset1
, max_size1
, offset2
, max_size2
))
995 ++alias_stats
.aliasing_component_refs_p_may_alias
;
1000 ++alias_stats
.aliasing_component_refs_p_no_alias
;
1006 /* If we didn't find a common base, try the other way around. */
1009 && compare_type_sizes (TREE_TYPE (end_struct_ref1
), type1
) <= 0))
1014 int cmp
= compare_type_sizes (type2
, TREE_TYPE (ref
));
1016 && (!end_struct_ref2
1017 || compare_type_sizes (TREE_TYPE (end_struct_ref2
),
1018 TREE_TYPE (ref
)) < 0))
1020 /* If types may be of same size, see if we can decide about their
1024 same_p1
= same_type_for_tbaa (TREE_TYPE (ref
), type2
);
1030 if (!handled_component_p (ref
))
1032 ref
= TREE_OPERAND (ref
, 0);
1036 poly_int64 offadj
, sztmp
, msztmp
;
1039 if (TREE_CODE (TREE_TYPE (base2
)) == ARRAY_TYPE
1040 && (!TYPE_SIZE (TREE_TYPE (base2
))
1041 || TREE_CODE (TYPE_SIZE (TREE_TYPE (base2
))) != INTEGER_CST
1044 ++alias_stats
.aliasing_component_refs_p_may_alias
;
1048 get_ref_base_and_extent (ref
, &offadj
, &sztmp
, &msztmp
, &reverse
);
1050 get_ref_base_and_extent (base2
, &offadj
, &sztmp
, &msztmp
, &reverse
);
1052 if (ranges_maybe_overlap_p (offset1
, max_size1
, offset2
, max_size2
))
1054 ++alias_stats
.aliasing_component_refs_p_may_alias
;
1059 ++alias_stats
.aliasing_component_refs_p_no_alias
;
1065 /* In the following code we make an assumption that the types in access
1066 paths do not overlap and thus accesses alias only if one path can be
1067 continuation of another. If we was not able to decide about equivalence,
1068 we need to give up. */
1072 /* If we have two type access paths B1.path1 and B2.path2 they may
1073 only alias if either B1 is in B2.path2 or B2 is in B1.path1.
1074 But we can still have a path that goes B1.path1...B2.path2 with
1075 a part that we do not see. So we can only disambiguate now
1076 if there is no B2 in the tail of path1 and no B1 on the
1078 if (compare_type_sizes (TREE_TYPE (ref2
), type1
) >= 0
1079 && (!end_struct_ref1
1080 || compare_type_sizes (TREE_TYPE (ref2
),
1081 TREE_TYPE (end_struct_ref1
)) >= 0)
1082 && type_has_components_p (TREE_TYPE (ref2
))
1083 && (base1_alias_set
== ref2_alias_set
1084 || alias_set_subset_of (base1_alias_set
, ref2_alias_set
)))
1086 ++alias_stats
.aliasing_component_refs_p_may_alias
;
1089 /* If this is ptr vs. decl then we know there is no ptr ... decl path. */
1090 if (compare_type_sizes (TREE_TYPE (ref1
), type2
) >= 0
1091 && (!end_struct_ref2
1092 || compare_type_sizes (TREE_TYPE (ref1
),
1093 TREE_TYPE (end_struct_ref2
)) >= 0)
1094 && type_has_components_p (TREE_TYPE (ref1
))
1095 && (base2_alias_set
== ref1_alias_set
1096 || alias_set_subset_of (base2_alias_set
, ref1_alias_set
)))
1098 ++alias_stats
.aliasing_component_refs_p_may_alias
;
1101 ++alias_stats
.aliasing_component_refs_p_no_alias
;
1105 /* Return true if we can determine that component references REF1 and REF2,
1106 that are within a common DECL, cannot overlap. */
1109 nonoverlapping_component_refs_of_decl_p (tree ref1
, tree ref2
)
1111 auto_vec
<tree
, 16> component_refs1
;
1112 auto_vec
<tree
, 16> component_refs2
;
1114 /* Create the stack of handled components for REF1. */
1115 while (handled_component_p (ref1
))
1117 component_refs1
.safe_push (ref1
);
1118 ref1
= TREE_OPERAND (ref1
, 0);
1120 if (TREE_CODE (ref1
) == MEM_REF
)
1122 if (!integer_zerop (TREE_OPERAND (ref1
, 1)))
1124 ++alias_stats
.nonoverlapping_component_refs_of_decl_p_may_alias
;
1127 ref1
= TREE_OPERAND (TREE_OPERAND (ref1
, 0), 0);
1130 /* Create the stack of handled components for REF2. */
1131 while (handled_component_p (ref2
))
1133 component_refs2
.safe_push (ref2
);
1134 ref2
= TREE_OPERAND (ref2
, 0);
1136 if (TREE_CODE (ref2
) == MEM_REF
)
1138 if (!integer_zerop (TREE_OPERAND (ref2
, 1)))
1140 ++alias_stats
.nonoverlapping_component_refs_of_decl_p_may_alias
;
1143 ref2
= TREE_OPERAND (TREE_OPERAND (ref2
, 0), 0);
1146 /* Bases must be either same or uncomparable. */
1147 gcc_checking_assert (ref1
== ref2
1148 || (DECL_P (ref1
) && DECL_P (ref2
)
1149 && compare_base_decls (ref1
, ref2
) != 0));
1151 /* Pop the stacks in parallel and examine the COMPONENT_REFs of the same
1152 rank. This is sufficient because we start from the same DECL and you
1153 cannot reference several fields at a time with COMPONENT_REFs (unlike
1154 with ARRAY_RANGE_REFs for arrays) so you always need the same number
1155 of them to access a sub-component, unless you're in a union, in which
1156 case the return value will precisely be false. */
1161 if (component_refs1
.is_empty ())
1163 ++alias_stats
.nonoverlapping_component_refs_of_decl_p_may_alias
;
1166 ref1
= component_refs1
.pop ();
1168 while (!RECORD_OR_UNION_TYPE_P (TREE_TYPE (TREE_OPERAND (ref1
, 0))));
1172 if (component_refs2
.is_empty ())
1174 ++alias_stats
.nonoverlapping_component_refs_of_decl_p_may_alias
;
1177 ref2
= component_refs2
.pop ();
1179 while (!RECORD_OR_UNION_TYPE_P (TREE_TYPE (TREE_OPERAND (ref2
, 0))));
1181 /* Beware of BIT_FIELD_REF. */
1182 if (TREE_CODE (ref1
) != COMPONENT_REF
1183 || TREE_CODE (ref2
) != COMPONENT_REF
)
1185 ++alias_stats
.nonoverlapping_component_refs_of_decl_p_may_alias
;
1189 tree field1
= TREE_OPERAND (ref1
, 1);
1190 tree field2
= TREE_OPERAND (ref2
, 1);
1192 /* ??? We cannot simply use the type of operand #0 of the refs here
1193 as the Fortran compiler smuggles type punning into COMPONENT_REFs
1194 for common blocks instead of using unions like everyone else. */
1195 tree type1
= DECL_CONTEXT (field1
);
1196 tree type2
= DECL_CONTEXT (field2
);
1198 /* We cannot disambiguate fields in a union or qualified union. */
1199 if (type1
!= type2
|| TREE_CODE (type1
) != RECORD_TYPE
)
1201 ++alias_stats
.nonoverlapping_component_refs_of_decl_p_may_alias
;
1205 if (field1
!= field2
)
1207 /* A field and its representative need to be considered the
1209 if (DECL_BIT_FIELD_REPRESENTATIVE (field1
) == field2
1210 || DECL_BIT_FIELD_REPRESENTATIVE (field2
) == field1
)
1212 ++alias_stats
.nonoverlapping_component_refs_of_decl_p_may_alias
;
1215 /* Different fields of the same record type cannot overlap.
1216 ??? Bitfields can overlap at RTL level so punt on them. */
1217 if (DECL_BIT_FIELD (field1
) && DECL_BIT_FIELD (field2
))
1219 ++alias_stats
.nonoverlapping_component_refs_of_decl_p_may_alias
;
1222 ++alias_stats
.nonoverlapping_component_refs_of_decl_p_no_alias
;
1227 ++alias_stats
.nonoverlapping_component_refs_of_decl_p_may_alias
;
1231 /* qsort compare function to sort FIELD_DECLs after their
1232 DECL_FIELD_CONTEXT TYPE_UID. */
1235 ncr_compar (const void *field1_
, const void *field2_
)
1237 const_tree field1
= *(const_tree
*) const_cast <void *>(field1_
);
1238 const_tree field2
= *(const_tree
*) const_cast <void *>(field2_
);
1239 unsigned int uid1
= TYPE_UID (DECL_FIELD_CONTEXT (field1
));
1240 unsigned int uid2
= TYPE_UID (DECL_FIELD_CONTEXT (field2
));
1243 else if (uid1
> uid2
)
1248 /* Return true if we can determine that the fields referenced cannot
1249 overlap for any pair of objects. */
1252 nonoverlapping_component_refs_p (const_tree x
, const_tree y
)
1254 if (!flag_strict_aliasing
1256 || !handled_component_p (x
)
1257 || !handled_component_p (y
))
1259 ++alias_stats
.nonoverlapping_component_refs_p_may_alias
;
1263 auto_vec
<const_tree
, 16> fieldsx
;
1264 while (handled_component_p (x
))
1266 if (TREE_CODE (x
) == COMPONENT_REF
)
1268 tree field
= TREE_OPERAND (x
, 1);
1269 tree type
= DECL_FIELD_CONTEXT (field
);
1270 if (TREE_CODE (type
) == RECORD_TYPE
)
1271 fieldsx
.safe_push (field
);
1273 else if (TREE_CODE (x
) == VIEW_CONVERT_EXPR
1274 || TREE_CODE (x
) == BIT_FIELD_REF
)
1275 fieldsx
.truncate (0);
1276 x
= TREE_OPERAND (x
, 0);
1278 if (fieldsx
.length () == 0)
1280 auto_vec
<const_tree
, 16> fieldsy
;
1281 while (handled_component_p (y
))
1283 if (TREE_CODE (y
) == COMPONENT_REF
)
1285 tree field
= TREE_OPERAND (y
, 1);
1286 tree type
= DECL_FIELD_CONTEXT (field
);
1287 if (TREE_CODE (type
) == RECORD_TYPE
)
1288 fieldsy
.safe_push (TREE_OPERAND (y
, 1));
1290 else if (TREE_CODE (y
) == VIEW_CONVERT_EXPR
1291 || TREE_CODE (y
) == BIT_FIELD_REF
)
1292 fieldsy
.truncate (0);
1293 y
= TREE_OPERAND (y
, 0);
1295 if (fieldsy
.length () == 0)
1297 ++alias_stats
.nonoverlapping_component_refs_p_may_alias
;
1301 /* Most common case first. */
1302 if (fieldsx
.length () == 1
1303 && fieldsy
.length () == 1)
1305 if ((DECL_FIELD_CONTEXT (fieldsx
[0])
1306 == DECL_FIELD_CONTEXT (fieldsy
[0]))
1307 && fieldsx
[0] != fieldsy
[0]
1308 && !(DECL_BIT_FIELD (fieldsx
[0]) && DECL_BIT_FIELD (fieldsy
[0])))
1310 ++alias_stats
.nonoverlapping_component_refs_p_no_alias
;
1315 ++alias_stats
.nonoverlapping_component_refs_p_may_alias
;
1320 if (fieldsx
.length () == 2)
1322 if (ncr_compar (&fieldsx
[0], &fieldsx
[1]) == 1)
1323 std::swap (fieldsx
[0], fieldsx
[1]);
1326 fieldsx
.qsort (ncr_compar
);
1328 if (fieldsy
.length () == 2)
1330 if (ncr_compar (&fieldsy
[0], &fieldsy
[1]) == 1)
1331 std::swap (fieldsy
[0], fieldsy
[1]);
1334 fieldsy
.qsort (ncr_compar
);
1336 unsigned i
= 0, j
= 0;
1339 const_tree fieldx
= fieldsx
[i
];
1340 const_tree fieldy
= fieldsy
[j
];
1341 tree typex
= DECL_FIELD_CONTEXT (fieldx
);
1342 tree typey
= DECL_FIELD_CONTEXT (fieldy
);
1345 /* We're left with accessing different fields of a structure,
1346 no possible overlap. */
1347 if (fieldx
!= fieldy
)
1349 /* A field and its representative need to be considered the
1351 if (DECL_BIT_FIELD_REPRESENTATIVE (fieldx
) == fieldy
1352 || DECL_BIT_FIELD_REPRESENTATIVE (fieldy
) == fieldx
)
1354 /* Different fields of the same record type cannot overlap.
1355 ??? Bitfields can overlap at RTL level so punt on them. */
1356 else if (DECL_BIT_FIELD (fieldx
) && DECL_BIT_FIELD (fieldy
))
1360 ++alias_stats
.nonoverlapping_component_refs_p_no_alias
;
1365 if (TYPE_UID (typex
) < TYPE_UID (typey
))
1368 if (i
== fieldsx
.length ())
1374 if (j
== fieldsy
.length ())
1380 ++alias_stats
.nonoverlapping_component_refs_p_may_alias
;
1385 /* Return true if two memory references based on the variables BASE1
1386 and BASE2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and
1387 [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. REF1 and REF2
1388 if non-NULL are the complete memory reference trees. */
1391 decl_refs_may_alias_p (tree ref1
, tree base1
,
1392 poly_int64 offset1
, poly_int64 max_size1
,
1393 tree ref2
, tree base2
,
1394 poly_int64 offset2
, poly_int64 max_size2
)
1396 gcc_checking_assert (DECL_P (base1
) && DECL_P (base2
));
1398 /* If both references are based on different variables, they cannot alias. */
1399 if (compare_base_decls (base1
, base2
) == 0)
1402 /* If both references are based on the same variable, they cannot alias if
1403 the accesses do not overlap. */
1404 if (!ranges_maybe_overlap_p (offset1
, max_size1
, offset2
, max_size2
))
1407 /* For components with variable position, the above test isn't sufficient,
1408 so we disambiguate component references manually. */
1410 && handled_component_p (ref1
) && handled_component_p (ref2
)
1411 && nonoverlapping_component_refs_of_decl_p (ref1
, ref2
))
1417 /* Return true if an indirect reference based on *PTR1 constrained
1418 to [OFFSET1, OFFSET1 + MAX_SIZE1) may alias a variable based on BASE2
1419 constrained to [OFFSET2, OFFSET2 + MAX_SIZE2). *PTR1 and BASE2 have
1420 the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1
1421 in which case they are computed on-demand. REF1 and REF2
1422 if non-NULL are the complete memory reference trees. */
1425 indirect_ref_may_alias_decl_p (tree ref1 ATTRIBUTE_UNUSED
, tree base1
,
1426 poly_int64 offset1
, poly_int64 max_size1
,
1427 alias_set_type ref1_alias_set
,
1428 alias_set_type base1_alias_set
,
1429 tree ref2 ATTRIBUTE_UNUSED
, tree base2
,
1430 poly_int64 offset2
, poly_int64 max_size2
,
1431 alias_set_type ref2_alias_set
,
1432 alias_set_type base2_alias_set
, bool tbaa_p
)
1435 tree ptrtype1
, dbase2
;
1437 gcc_checking_assert ((TREE_CODE (base1
) == MEM_REF
1438 || TREE_CODE (base1
) == TARGET_MEM_REF
)
1441 ptr1
= TREE_OPERAND (base1
, 0);
1442 poly_offset_int moff
= mem_ref_offset (base1
) << LOG2_BITS_PER_UNIT
;
1444 /* If only one reference is based on a variable, they cannot alias if
1445 the pointer access is beyond the extent of the variable access.
1446 (the pointer base cannot validly point to an offset less than zero
1448 ??? IVOPTs creates bases that do not honor this restriction,
1449 so do not apply this optimization for TARGET_MEM_REFs. */
1450 if (TREE_CODE (base1
) != TARGET_MEM_REF
1451 && !ranges_maybe_overlap_p (offset1
+ moff
, -1, offset2
, max_size2
))
1453 /* They also cannot alias if the pointer may not point to the decl. */
1454 if (!ptr_deref_may_alias_decl_p (ptr1
, base2
))
1457 /* Disambiguations that rely on strict aliasing rules follow. */
1458 if (!flag_strict_aliasing
|| !tbaa_p
)
1461 ptrtype1
= TREE_TYPE (TREE_OPERAND (base1
, 1));
1463 /* If the alias set for a pointer access is zero all bets are off. */
1464 if (base1_alias_set
== 0)
1467 /* When we are trying to disambiguate an access with a pointer dereference
1468 as base versus one with a decl as base we can use both the size
1469 of the decl and its dynamic type for extra disambiguation.
1470 ??? We do not know anything about the dynamic type of the decl
1471 other than that its alias-set contains base2_alias_set as a subset
1472 which does not help us here. */
1473 /* As we know nothing useful about the dynamic type of the decl just
1474 use the usual conflict check rather than a subset test.
1475 ??? We could introduce -fvery-strict-aliasing when the language
1476 does not allow decls to have a dynamic type that differs from their
1477 static type. Then we can check
1478 !alias_set_subset_of (base1_alias_set, base2_alias_set) instead. */
1479 if (base1_alias_set
!= base2_alias_set
1480 && !alias_sets_conflict_p (base1_alias_set
, base2_alias_set
))
1482 /* If the size of the access relevant for TBAA through the pointer
1483 is bigger than the size of the decl we can't possibly access the
1484 decl via that pointer. */
1485 if (/* ??? This in turn may run afoul when a decl of type T which is
1486 a member of union type U is accessed through a pointer to
1487 type U and sizeof T is smaller than sizeof U. */
1488 TREE_CODE (TREE_TYPE (ptrtype1
)) != UNION_TYPE
1489 && TREE_CODE (TREE_TYPE (ptrtype1
)) != QUAL_UNION_TYPE
1490 && compare_sizes (DECL_SIZE (base2
),
1491 TYPE_SIZE (TREE_TYPE (ptrtype1
))) < 0)
1497 /* If the decl is accessed via a MEM_REF, reconstruct the base
1498 we can use for TBAA and an appropriately adjusted offset. */
1500 while (handled_component_p (dbase2
))
1501 dbase2
= TREE_OPERAND (dbase2
, 0);
1502 poly_int64 doffset1
= offset1
;
1503 poly_offset_int doffset2
= offset2
;
1504 if (TREE_CODE (dbase2
) == MEM_REF
1505 || TREE_CODE (dbase2
) == TARGET_MEM_REF
)
1507 doffset2
-= mem_ref_offset (dbase2
) << LOG2_BITS_PER_UNIT
;
1508 tree ptrtype2
= TREE_TYPE (TREE_OPERAND (dbase2
, 1));
1509 /* If second reference is view-converted, give up now. */
1510 if (same_type_for_tbaa (TREE_TYPE (dbase2
), TREE_TYPE (ptrtype2
)) != 1)
1514 /* If first reference is view-converted, give up now. */
1515 if (same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (ptrtype1
)) != 1)
1518 /* If both references are through the same type, they do not alias
1519 if the accesses do not overlap. This does extra disambiguation
1520 for mixed/pointer accesses but requires strict aliasing.
1521 For MEM_REFs we require that the component-ref offset we computed
1522 is relative to the start of the type which we ensure by
1523 comparing rvalue and access type and disregarding the constant
1526 But avoid treating variable length arrays as "objects", instead assume they
1527 can overlap by an exact multiple of their element size.
1528 See gcc.dg/torture/alias-2.c. */
1529 if (((TREE_CODE (base1
) != TARGET_MEM_REF
1530 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1531 && (TREE_CODE (dbase2
) != TARGET_MEM_REF
1532 || (!TMR_INDEX (dbase2
) && !TMR_INDEX2 (dbase2
))))
1533 && same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (dbase2
)) == 1
1534 && (TREE_CODE (TREE_TYPE (base1
)) != ARRAY_TYPE
1535 || (TYPE_SIZE (TREE_TYPE (base1
))
1536 && TREE_CODE (TYPE_SIZE (TREE_TYPE (base1
))) == INTEGER_CST
)))
1537 return ranges_maybe_overlap_p (doffset1
, max_size1
, doffset2
, max_size2
);
1540 && nonoverlapping_component_refs_p (ref1
, ref2
))
1543 /* Do access-path based disambiguation. */
1545 && (handled_component_p (ref1
) || handled_component_p (ref2
)))
1546 return aliasing_component_refs_p (ref1
,
1547 ref1_alias_set
, base1_alias_set
,
1550 ref2_alias_set
, base2_alias_set
,
1551 offset2
, max_size2
);
1556 /* Return true if two indirect references based on *PTR1
1557 and *PTR2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and
1558 [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. *PTR1 and *PTR2 have
1559 the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1
1560 in which case they are computed on-demand. REF1 and REF2
1561 if non-NULL are the complete memory reference trees. */
1564 indirect_refs_may_alias_p (tree ref1 ATTRIBUTE_UNUSED
, tree base1
,
1565 poly_int64 offset1
, poly_int64 max_size1
,
1566 alias_set_type ref1_alias_set
,
1567 alias_set_type base1_alias_set
,
1568 tree ref2 ATTRIBUTE_UNUSED
, tree base2
,
1569 poly_int64 offset2
, poly_int64 max_size2
,
1570 alias_set_type ref2_alias_set
,
1571 alias_set_type base2_alias_set
, bool tbaa_p
)
1575 tree ptrtype1
, ptrtype2
;
1577 gcc_checking_assert ((TREE_CODE (base1
) == MEM_REF
1578 || TREE_CODE (base1
) == TARGET_MEM_REF
)
1579 && (TREE_CODE (base2
) == MEM_REF
1580 || TREE_CODE (base2
) == TARGET_MEM_REF
));
1582 ptr1
= TREE_OPERAND (base1
, 0);
1583 ptr2
= TREE_OPERAND (base2
, 0);
1585 /* If both bases are based on pointers they cannot alias if they may not
1586 point to the same memory object or if they point to the same object
1587 and the accesses do not overlap. */
1588 if ((!cfun
|| gimple_in_ssa_p (cfun
))
1589 && operand_equal_p (ptr1
, ptr2
, 0)
1590 && (((TREE_CODE (base1
) != TARGET_MEM_REF
1591 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1592 && (TREE_CODE (base2
) != TARGET_MEM_REF
1593 || (!TMR_INDEX (base2
) && !TMR_INDEX2 (base2
))))
1594 || (TREE_CODE (base1
) == TARGET_MEM_REF
1595 && TREE_CODE (base2
) == TARGET_MEM_REF
1596 && (TMR_STEP (base1
) == TMR_STEP (base2
)
1597 || (TMR_STEP (base1
) && TMR_STEP (base2
)
1598 && operand_equal_p (TMR_STEP (base1
),
1599 TMR_STEP (base2
), 0)))
1600 && (TMR_INDEX (base1
) == TMR_INDEX (base2
)
1601 || (TMR_INDEX (base1
) && TMR_INDEX (base2
)
1602 && operand_equal_p (TMR_INDEX (base1
),
1603 TMR_INDEX (base2
), 0)))
1604 && (TMR_INDEX2 (base1
) == TMR_INDEX2 (base2
)
1605 || (TMR_INDEX2 (base1
) && TMR_INDEX2 (base2
)
1606 && operand_equal_p (TMR_INDEX2 (base1
),
1607 TMR_INDEX2 (base2
), 0))))))
1609 poly_offset_int moff1
= mem_ref_offset (base1
) << LOG2_BITS_PER_UNIT
;
1610 poly_offset_int moff2
= mem_ref_offset (base2
) << LOG2_BITS_PER_UNIT
;
1611 return ranges_maybe_overlap_p (offset1
+ moff1
, max_size1
,
1612 offset2
+ moff2
, max_size2
);
1614 if (!ptr_derefs_may_alias_p (ptr1
, ptr2
))
1617 /* Disambiguations that rely on strict aliasing rules follow. */
1618 if (!flag_strict_aliasing
|| !tbaa_p
)
1621 ptrtype1
= TREE_TYPE (TREE_OPERAND (base1
, 1));
1622 ptrtype2
= TREE_TYPE (TREE_OPERAND (base2
, 1));
1624 /* If the alias set for a pointer access is zero all bets are off. */
1625 if (base1_alias_set
== 0
1626 || base2_alias_set
== 0)
1629 /* Do type-based disambiguation. */
1630 if (base1_alias_set
!= base2_alias_set
1631 && !alias_sets_conflict_p (base1_alias_set
, base2_alias_set
))
1634 /* If either reference is view-converted, give up now. */
1635 if (same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (ptrtype1
)) != 1
1636 || same_type_for_tbaa (TREE_TYPE (base2
), TREE_TYPE (ptrtype2
)) != 1)
1639 /* If both references are through the same type, they do not alias
1640 if the accesses do not overlap. This does extra disambiguation
1641 for mixed/pointer accesses but requires strict aliasing. */
1642 if ((TREE_CODE (base1
) != TARGET_MEM_REF
1643 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1644 && (TREE_CODE (base2
) != TARGET_MEM_REF
1645 || (!TMR_INDEX (base2
) && !TMR_INDEX2 (base2
)))
1646 && same_type_for_tbaa (TREE_TYPE (ptrtype1
),
1647 TREE_TYPE (ptrtype2
)) == 1
1648 /* But avoid treating arrays as "objects", instead assume they
1649 can overlap by an exact multiple of their element size.
1650 See gcc.dg/torture/alias-2.c. */
1651 && TREE_CODE (TREE_TYPE (ptrtype1
)) != ARRAY_TYPE
)
1652 return ranges_maybe_overlap_p (offset1
, max_size1
, offset2
, max_size2
);
1655 && nonoverlapping_component_refs_p (ref1
, ref2
))
1658 /* Do access-path based disambiguation. */
1660 && (handled_component_p (ref1
) || handled_component_p (ref2
)))
1661 return aliasing_component_refs_p (ref1
,
1662 ref1_alias_set
, base1_alias_set
,
1665 ref2_alias_set
, base2_alias_set
,
1666 offset2
, max_size2
);
1671 /* Return true, if the two memory references REF1 and REF2 may alias. */
1674 refs_may_alias_p_2 (ao_ref
*ref1
, ao_ref
*ref2
, bool tbaa_p
)
1677 poly_int64 offset1
= 0, offset2
= 0;
1678 poly_int64 max_size1
= -1, max_size2
= -1;
1679 bool var1_p
, var2_p
, ind1_p
, ind2_p
;
1681 gcc_checking_assert ((!ref1
->ref
1682 || TREE_CODE (ref1
->ref
) == SSA_NAME
1683 || DECL_P (ref1
->ref
)
1684 || TREE_CODE (ref1
->ref
) == STRING_CST
1685 || handled_component_p (ref1
->ref
)
1686 || TREE_CODE (ref1
->ref
) == MEM_REF
1687 || TREE_CODE (ref1
->ref
) == TARGET_MEM_REF
)
1689 || TREE_CODE (ref2
->ref
) == SSA_NAME
1690 || DECL_P (ref2
->ref
)
1691 || TREE_CODE (ref2
->ref
) == STRING_CST
1692 || handled_component_p (ref2
->ref
)
1693 || TREE_CODE (ref2
->ref
) == MEM_REF
1694 || TREE_CODE (ref2
->ref
) == TARGET_MEM_REF
));
1696 /* Decompose the references into their base objects and the access. */
1697 base1
= ao_ref_base (ref1
);
1698 offset1
= ref1
->offset
;
1699 max_size1
= ref1
->max_size
;
1700 base2
= ao_ref_base (ref2
);
1701 offset2
= ref2
->offset
;
1702 max_size2
= ref2
->max_size
;
1704 /* We can end up with registers or constants as bases for example from
1705 *D.1663_44 = VIEW_CONVERT_EXPR<struct DB_LSN>(__tmp$B0F64_59);
1706 which is seen as a struct copy. */
1707 if (TREE_CODE (base1
) == SSA_NAME
1708 || TREE_CODE (base1
) == CONST_DECL
1709 || TREE_CODE (base1
) == CONSTRUCTOR
1710 || TREE_CODE (base1
) == ADDR_EXPR
1711 || CONSTANT_CLASS_P (base1
)
1712 || TREE_CODE (base2
) == SSA_NAME
1713 || TREE_CODE (base2
) == CONST_DECL
1714 || TREE_CODE (base2
) == CONSTRUCTOR
1715 || TREE_CODE (base2
) == ADDR_EXPR
1716 || CONSTANT_CLASS_P (base2
))
1719 /* We can end up referring to code via function and label decls.
1720 As we likely do not properly track code aliases conservatively
1722 if (TREE_CODE (base1
) == FUNCTION_DECL
1723 || TREE_CODE (base1
) == LABEL_DECL
1724 || TREE_CODE (base2
) == FUNCTION_DECL
1725 || TREE_CODE (base2
) == LABEL_DECL
)
1728 /* Two volatile accesses always conflict. */
1729 if (ref1
->volatile_p
1730 && ref2
->volatile_p
)
1733 /* Defer to simple offset based disambiguation if we have
1734 references based on two decls. Do this before defering to
1735 TBAA to handle must-alias cases in conformance with the
1736 GCC extension of allowing type-punning through unions. */
1737 var1_p
= DECL_P (base1
);
1738 var2_p
= DECL_P (base2
);
1739 if (var1_p
&& var2_p
)
1740 return decl_refs_may_alias_p (ref1
->ref
, base1
, offset1
, max_size1
,
1741 ref2
->ref
, base2
, offset2
, max_size2
);
1743 /* Handle restrict based accesses.
1744 ??? ao_ref_base strips inner MEM_REF [&decl], recover from that
1746 tree rbase1
= base1
;
1747 tree rbase2
= base2
;
1752 while (handled_component_p (rbase1
))
1753 rbase1
= TREE_OPERAND (rbase1
, 0);
1759 while (handled_component_p (rbase2
))
1760 rbase2
= TREE_OPERAND (rbase2
, 0);
1762 if (rbase1
&& rbase2
1763 && (TREE_CODE (base1
) == MEM_REF
|| TREE_CODE (base1
) == TARGET_MEM_REF
)
1764 && (TREE_CODE (base2
) == MEM_REF
|| TREE_CODE (base2
) == TARGET_MEM_REF
)
1765 /* If the accesses are in the same restrict clique... */
1766 && MR_DEPENDENCE_CLIQUE (base1
) == MR_DEPENDENCE_CLIQUE (base2
)
1767 /* But based on different pointers they do not alias. */
1768 && MR_DEPENDENCE_BASE (base1
) != MR_DEPENDENCE_BASE (base2
))
1771 ind1_p
= (TREE_CODE (base1
) == MEM_REF
1772 || TREE_CODE (base1
) == TARGET_MEM_REF
);
1773 ind2_p
= (TREE_CODE (base2
) == MEM_REF
1774 || TREE_CODE (base2
) == TARGET_MEM_REF
);
1776 /* Canonicalize the pointer-vs-decl case. */
1777 if (ind1_p
&& var2_p
)
1779 std::swap (offset1
, offset2
);
1780 std::swap (max_size1
, max_size2
);
1781 std::swap (base1
, base2
);
1782 std::swap (ref1
, ref2
);
1789 /* First defer to TBAA if possible. */
1791 && flag_strict_aliasing
1792 && !alias_sets_conflict_p (ao_ref_alias_set (ref1
),
1793 ao_ref_alias_set (ref2
)))
1796 /* If the reference is based on a pointer that points to memory
1797 that may not be written to then the other reference cannot possibly
1799 if ((TREE_CODE (TREE_OPERAND (base2
, 0)) == SSA_NAME
1800 && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base2
, 0)))
1802 && TREE_CODE (TREE_OPERAND (base1
, 0)) == SSA_NAME
1803 && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base1
, 0))))
1806 /* Dispatch to the pointer-vs-decl or pointer-vs-pointer disambiguators. */
1807 if (var1_p
&& ind2_p
)
1808 return indirect_ref_may_alias_decl_p (ref2
->ref
, base2
,
1810 ao_ref_alias_set (ref2
),
1811 ao_ref_base_alias_set (ref2
),
1814 ao_ref_alias_set (ref1
),
1815 ao_ref_base_alias_set (ref1
),
1817 else if (ind1_p
&& ind2_p
)
1818 return indirect_refs_may_alias_p (ref1
->ref
, base1
,
1820 ao_ref_alias_set (ref1
),
1821 ao_ref_base_alias_set (ref1
),
1824 ao_ref_alias_set (ref2
),
1825 ao_ref_base_alias_set (ref2
),
1831 /* Return true, if the two memory references REF1 and REF2 may alias
1832 and update statistics. */
1835 refs_may_alias_p_1 (ao_ref
*ref1
, ao_ref
*ref2
, bool tbaa_p
)
1837 bool res
= refs_may_alias_p_2 (ref1
, ref2
, tbaa_p
);
1839 ++alias_stats
.refs_may_alias_p_may_alias
;
1841 ++alias_stats
.refs_may_alias_p_no_alias
;
1846 refs_may_alias_p (tree ref1
, ao_ref
*ref2
, bool tbaa_p
)
1849 ao_ref_init (&r1
, ref1
);
1850 return refs_may_alias_p_1 (&r1
, ref2
, tbaa_p
);
1854 refs_may_alias_p (tree ref1
, tree ref2
, bool tbaa_p
)
1857 ao_ref_init (&r1
, ref1
);
1858 ao_ref_init (&r2
, ref2
);
1859 return refs_may_alias_p_1 (&r1
, &r2
, tbaa_p
);
1862 /* Returns true if there is a anti-dependence for the STORE that
1863 executes after the LOAD. */
1866 refs_anti_dependent_p (tree load
, tree store
)
1869 ao_ref_init (&r1
, load
);
1870 ao_ref_init (&r2
, store
);
1871 return refs_may_alias_p_1 (&r1
, &r2
, false);
1874 /* Returns true if there is a output dependence for the stores
1875 STORE1 and STORE2. */
1878 refs_output_dependent_p (tree store1
, tree store2
)
1881 ao_ref_init (&r1
, store1
);
1882 ao_ref_init (&r2
, store2
);
1883 return refs_may_alias_p_1 (&r1
, &r2
, false);
1886 /* If the call CALL may use the memory reference REF return true,
1887 otherwise return false. */
1890 ref_maybe_used_by_call_p_1 (gcall
*call
, ao_ref
*ref
, bool tbaa_p
)
1894 int flags
= gimple_call_flags (call
);
1896 /* Const functions without a static chain do not implicitly use memory. */
1897 if (!gimple_call_chain (call
)
1898 && (flags
& (ECF_CONST
|ECF_NOVOPS
)))
1901 base
= ao_ref_base (ref
);
1905 /* A call that is not without side-effects might involve volatile
1906 accesses and thus conflicts with all other volatile accesses. */
1907 if (ref
->volatile_p
)
1910 /* If the reference is based on a decl that is not aliased the call
1911 cannot possibly use it. */
1913 && !may_be_aliased (base
)
1914 /* But local statics can be used through recursion. */
1915 && !is_global_var (base
))
1918 callee
= gimple_call_fndecl (call
);
1920 /* Handle those builtin functions explicitly that do not act as
1921 escape points. See tree-ssa-structalias.c:find_func_aliases
1922 for the list of builtins we might need to handle here. */
1923 if (callee
!= NULL_TREE
1924 && gimple_call_builtin_p (call
, BUILT_IN_NORMAL
))
1925 switch (DECL_FUNCTION_CODE (callee
))
1927 /* All the following functions read memory pointed to by
1928 their second argument. strcat/strncat additionally
1929 reads memory pointed to by the first argument. */
1930 case BUILT_IN_STRCAT
:
1931 case BUILT_IN_STRNCAT
:
1934 ao_ref_init_from_ptr_and_size (&dref
,
1935 gimple_call_arg (call
, 0),
1937 if (refs_may_alias_p_1 (&dref
, ref
, false))
1941 case BUILT_IN_STRCPY
:
1942 case BUILT_IN_STRNCPY
:
1943 case BUILT_IN_MEMCPY
:
1944 case BUILT_IN_MEMMOVE
:
1945 case BUILT_IN_MEMPCPY
:
1946 case BUILT_IN_STPCPY
:
1947 case BUILT_IN_STPNCPY
:
1948 case BUILT_IN_TM_MEMCPY
:
1949 case BUILT_IN_TM_MEMMOVE
:
1952 tree size
= NULL_TREE
;
1953 if (gimple_call_num_args (call
) == 3)
1954 size
= gimple_call_arg (call
, 2);
1955 ao_ref_init_from_ptr_and_size (&dref
,
1956 gimple_call_arg (call
, 1),
1958 return refs_may_alias_p_1 (&dref
, ref
, false);
1960 case BUILT_IN_STRCAT_CHK
:
1961 case BUILT_IN_STRNCAT_CHK
:
1964 ao_ref_init_from_ptr_and_size (&dref
,
1965 gimple_call_arg (call
, 0),
1967 if (refs_may_alias_p_1 (&dref
, ref
, false))
1971 case BUILT_IN_STRCPY_CHK
:
1972 case BUILT_IN_STRNCPY_CHK
:
1973 case BUILT_IN_MEMCPY_CHK
:
1974 case BUILT_IN_MEMMOVE_CHK
:
1975 case BUILT_IN_MEMPCPY_CHK
:
1976 case BUILT_IN_STPCPY_CHK
:
1977 case BUILT_IN_STPNCPY_CHK
:
1980 tree size
= NULL_TREE
;
1981 if (gimple_call_num_args (call
) == 4)
1982 size
= gimple_call_arg (call
, 2);
1983 ao_ref_init_from_ptr_and_size (&dref
,
1984 gimple_call_arg (call
, 1),
1986 return refs_may_alias_p_1 (&dref
, ref
, false);
1988 case BUILT_IN_BCOPY
:
1991 tree size
= gimple_call_arg (call
, 2);
1992 ao_ref_init_from_ptr_and_size (&dref
,
1993 gimple_call_arg (call
, 0),
1995 return refs_may_alias_p_1 (&dref
, ref
, false);
1998 /* The following functions read memory pointed to by their
2000 CASE_BUILT_IN_TM_LOAD (1):
2001 CASE_BUILT_IN_TM_LOAD (2):
2002 CASE_BUILT_IN_TM_LOAD (4):
2003 CASE_BUILT_IN_TM_LOAD (8):
2004 CASE_BUILT_IN_TM_LOAD (FLOAT
):
2005 CASE_BUILT_IN_TM_LOAD (DOUBLE
):
2006 CASE_BUILT_IN_TM_LOAD (LDOUBLE
):
2007 CASE_BUILT_IN_TM_LOAD (M64
):
2008 CASE_BUILT_IN_TM_LOAD (M128
):
2009 CASE_BUILT_IN_TM_LOAD (M256
):
2010 case BUILT_IN_TM_LOG
:
2011 case BUILT_IN_TM_LOG_1
:
2012 case BUILT_IN_TM_LOG_2
:
2013 case BUILT_IN_TM_LOG_4
:
2014 case BUILT_IN_TM_LOG_8
:
2015 case BUILT_IN_TM_LOG_FLOAT
:
2016 case BUILT_IN_TM_LOG_DOUBLE
:
2017 case BUILT_IN_TM_LOG_LDOUBLE
:
2018 case BUILT_IN_TM_LOG_M64
:
2019 case BUILT_IN_TM_LOG_M128
:
2020 case BUILT_IN_TM_LOG_M256
:
2021 return ptr_deref_may_alias_ref_p_1 (gimple_call_arg (call
, 0), ref
);
2023 /* These read memory pointed to by the first argument. */
2024 case BUILT_IN_STRDUP
:
2025 case BUILT_IN_STRNDUP
:
2026 case BUILT_IN_REALLOC
:
2029 tree size
= NULL_TREE
;
2030 if (gimple_call_num_args (call
) == 2)
2031 size
= gimple_call_arg (call
, 1);
2032 ao_ref_init_from_ptr_and_size (&dref
,
2033 gimple_call_arg (call
, 0),
2035 return refs_may_alias_p_1 (&dref
, ref
, false);
2037 /* These read memory pointed to by the first argument. */
2038 case BUILT_IN_INDEX
:
2039 case BUILT_IN_STRCHR
:
2040 case BUILT_IN_STRRCHR
:
2043 ao_ref_init_from_ptr_and_size (&dref
,
2044 gimple_call_arg (call
, 0),
2046 return refs_may_alias_p_1 (&dref
, ref
, false);
2048 /* These read memory pointed to by the first argument with size
2049 in the third argument. */
2050 case BUILT_IN_MEMCHR
:
2053 ao_ref_init_from_ptr_and_size (&dref
,
2054 gimple_call_arg (call
, 0),
2055 gimple_call_arg (call
, 2));
2056 return refs_may_alias_p_1 (&dref
, ref
, false);
2058 /* These read memory pointed to by the first and second arguments. */
2059 case BUILT_IN_STRSTR
:
2060 case BUILT_IN_STRPBRK
:
2063 ao_ref_init_from_ptr_and_size (&dref
,
2064 gimple_call_arg (call
, 0),
2066 if (refs_may_alias_p_1 (&dref
, ref
, false))
2068 ao_ref_init_from_ptr_and_size (&dref
,
2069 gimple_call_arg (call
, 1),
2071 return refs_may_alias_p_1 (&dref
, ref
, false);
2074 /* The following builtins do not read from memory. */
2076 case BUILT_IN_MALLOC
:
2077 case BUILT_IN_POSIX_MEMALIGN
:
2078 case BUILT_IN_ALIGNED_ALLOC
:
2079 case BUILT_IN_CALLOC
:
2080 CASE_BUILT_IN_ALLOCA
:
2081 case BUILT_IN_STACK_SAVE
:
2082 case BUILT_IN_STACK_RESTORE
:
2083 case BUILT_IN_MEMSET
:
2084 case BUILT_IN_TM_MEMSET
:
2085 case BUILT_IN_MEMSET_CHK
:
2086 case BUILT_IN_FREXP
:
2087 case BUILT_IN_FREXPF
:
2088 case BUILT_IN_FREXPL
:
2089 case BUILT_IN_GAMMA_R
:
2090 case BUILT_IN_GAMMAF_R
:
2091 case BUILT_IN_GAMMAL_R
:
2092 case BUILT_IN_LGAMMA_R
:
2093 case BUILT_IN_LGAMMAF_R
:
2094 case BUILT_IN_LGAMMAL_R
:
2096 case BUILT_IN_MODFF
:
2097 case BUILT_IN_MODFL
:
2098 case BUILT_IN_REMQUO
:
2099 case BUILT_IN_REMQUOF
:
2100 case BUILT_IN_REMQUOL
:
2101 case BUILT_IN_SINCOS
:
2102 case BUILT_IN_SINCOSF
:
2103 case BUILT_IN_SINCOSL
:
2104 case BUILT_IN_ASSUME_ALIGNED
:
2105 case BUILT_IN_VA_END
:
2107 /* __sync_* builtins and some OpenMP builtins act as threading
2109 #undef DEF_SYNC_BUILTIN
2110 #define DEF_SYNC_BUILTIN(ENUM, NAME, TYPE, ATTRS) case ENUM:
2111 #include "sync-builtins.def"
2112 #undef DEF_SYNC_BUILTIN
2113 case BUILT_IN_GOMP_ATOMIC_START
:
2114 case BUILT_IN_GOMP_ATOMIC_END
:
2115 case BUILT_IN_GOMP_BARRIER
:
2116 case BUILT_IN_GOMP_BARRIER_CANCEL
:
2117 case BUILT_IN_GOMP_TASKWAIT
:
2118 case BUILT_IN_GOMP_TASKGROUP_END
:
2119 case BUILT_IN_GOMP_CRITICAL_START
:
2120 case BUILT_IN_GOMP_CRITICAL_END
:
2121 case BUILT_IN_GOMP_CRITICAL_NAME_START
:
2122 case BUILT_IN_GOMP_CRITICAL_NAME_END
:
2123 case BUILT_IN_GOMP_LOOP_END
:
2124 case BUILT_IN_GOMP_LOOP_END_CANCEL
:
2125 case BUILT_IN_GOMP_ORDERED_START
:
2126 case BUILT_IN_GOMP_ORDERED_END
:
2127 case BUILT_IN_GOMP_SECTIONS_END
:
2128 case BUILT_IN_GOMP_SECTIONS_END_CANCEL
:
2129 case BUILT_IN_GOMP_SINGLE_COPY_START
:
2130 case BUILT_IN_GOMP_SINGLE_COPY_END
:
2134 /* Fallthru to general call handling. */;
2137 /* Check if base is a global static variable that is not read
2139 if (callee
!= NULL_TREE
&& VAR_P (base
) && TREE_STATIC (base
))
2141 struct cgraph_node
*node
= cgraph_node::get (callee
);
2144 /* FIXME: Callee can be an OMP builtin that does not have a call graph
2145 node yet. We should enforce that there are nodes for all decls in the
2146 IL and remove this check instead. */
2148 && (not_read
= ipa_reference_get_not_read_global (node
))
2149 && bitmap_bit_p (not_read
, ipa_reference_var_uid (base
)))
2153 /* Check if the base variable is call-used. */
2156 if (pt_solution_includes (gimple_call_use_set (call
), base
))
2159 else if ((TREE_CODE (base
) == MEM_REF
2160 || TREE_CODE (base
) == TARGET_MEM_REF
)
2161 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
)
2163 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (TREE_OPERAND (base
, 0));
2167 if (pt_solutions_intersect (gimple_call_use_set (call
), &pi
->pt
))
2173 /* Inspect call arguments for passed-by-value aliases. */
2175 for (i
= 0; i
< gimple_call_num_args (call
); ++i
)
2177 tree op
= gimple_call_arg (call
, i
);
2178 int flags
= gimple_call_arg_flags (call
, i
);
2180 if (flags
& EAF_UNUSED
)
2183 if (TREE_CODE (op
) == WITH_SIZE_EXPR
)
2184 op
= TREE_OPERAND (op
, 0);
2186 if (TREE_CODE (op
) != SSA_NAME
2187 && !is_gimple_min_invariant (op
))
2190 ao_ref_init (&r
, op
);
2191 if (refs_may_alias_p_1 (&r
, ref
, tbaa_p
))
2200 ref_maybe_used_by_call_p (gcall
*call
, ao_ref
*ref
, bool tbaa_p
)
2203 res
= ref_maybe_used_by_call_p_1 (call
, ref
, tbaa_p
);
2205 ++alias_stats
.ref_maybe_used_by_call_p_may_alias
;
2207 ++alias_stats
.ref_maybe_used_by_call_p_no_alias
;
2212 /* If the statement STMT may use the memory reference REF return
2213 true, otherwise return false. */
2216 ref_maybe_used_by_stmt_p (gimple
*stmt
, ao_ref
*ref
, bool tbaa_p
)
2218 if (is_gimple_assign (stmt
))
2222 /* All memory assign statements are single. */
2223 if (!gimple_assign_single_p (stmt
))
2226 rhs
= gimple_assign_rhs1 (stmt
);
2227 if (is_gimple_reg (rhs
)
2228 || is_gimple_min_invariant (rhs
)
2229 || gimple_assign_rhs_code (stmt
) == CONSTRUCTOR
)
2232 return refs_may_alias_p (rhs
, ref
, tbaa_p
);
2234 else if (is_gimple_call (stmt
))
2235 return ref_maybe_used_by_call_p (as_a
<gcall
*> (stmt
), ref
, tbaa_p
);
2236 else if (greturn
*return_stmt
= dyn_cast
<greturn
*> (stmt
))
2238 tree retval
= gimple_return_retval (return_stmt
);
2240 && TREE_CODE (retval
) != SSA_NAME
2241 && !is_gimple_min_invariant (retval
)
2242 && refs_may_alias_p (retval
, ref
, tbaa_p
))
2244 /* If ref escapes the function then the return acts as a use. */
2245 tree base
= ao_ref_base (ref
);
2248 else if (DECL_P (base
))
2249 return is_global_var (base
);
2250 else if (TREE_CODE (base
) == MEM_REF
2251 || TREE_CODE (base
) == TARGET_MEM_REF
)
2252 return ptr_deref_may_alias_global_p (TREE_OPERAND (base
, 0));
2260 ref_maybe_used_by_stmt_p (gimple
*stmt
, tree ref
, bool tbaa_p
)
2263 ao_ref_init (&r
, ref
);
2264 return ref_maybe_used_by_stmt_p (stmt
, &r
, tbaa_p
);
2267 /* If the call in statement CALL may clobber the memory reference REF
2268 return true, otherwise return false. */
2271 call_may_clobber_ref_p_1 (gcall
*call
, ao_ref
*ref
)
2276 /* If the call is pure or const it cannot clobber anything. */
2277 if (gimple_call_flags (call
)
2278 & (ECF_PURE
|ECF_CONST
|ECF_LOOPING_CONST_OR_PURE
|ECF_NOVOPS
))
2280 if (gimple_call_internal_p (call
))
2281 switch (gimple_call_internal_fn (call
))
2283 /* Treat these internal calls like ECF_PURE for aliasing,
2284 they don't write to any memory the program should care about.
2285 They have important other side-effects, and read memory,
2286 so can't be ECF_NOVOPS. */
2287 case IFN_UBSAN_NULL
:
2288 case IFN_UBSAN_BOUNDS
:
2289 case IFN_UBSAN_VPTR
:
2290 case IFN_UBSAN_OBJECT_SIZE
:
2292 case IFN_ASAN_CHECK
:
2298 base
= ao_ref_base (ref
);
2302 if (TREE_CODE (base
) == SSA_NAME
2303 || CONSTANT_CLASS_P (base
))
2306 /* A call that is not without side-effects might involve volatile
2307 accesses and thus conflicts with all other volatile accesses. */
2308 if (ref
->volatile_p
)
2311 /* If the reference is based on a decl that is not aliased the call
2312 cannot possibly clobber it. */
2314 && !may_be_aliased (base
)
2315 /* But local non-readonly statics can be modified through recursion
2316 or the call may implement a threading barrier which we must
2317 treat as may-def. */
2318 && (TREE_READONLY (base
)
2319 || !is_global_var (base
)))
2322 /* If the reference is based on a pointer that points to memory
2323 that may not be written to then the call cannot possibly clobber it. */
2324 if ((TREE_CODE (base
) == MEM_REF
2325 || TREE_CODE (base
) == TARGET_MEM_REF
)
2326 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
2327 && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base
, 0)))
2330 callee
= gimple_call_fndecl (call
);
2332 /* Handle those builtin functions explicitly that do not act as
2333 escape points. See tree-ssa-structalias.c:find_func_aliases
2334 for the list of builtins we might need to handle here. */
2335 if (callee
!= NULL_TREE
2336 && gimple_call_builtin_p (call
, BUILT_IN_NORMAL
))
2337 switch (DECL_FUNCTION_CODE (callee
))
2339 /* All the following functions clobber memory pointed to by
2340 their first argument. */
2341 case BUILT_IN_STRCPY
:
2342 case BUILT_IN_STRNCPY
:
2343 case BUILT_IN_MEMCPY
:
2344 case BUILT_IN_MEMMOVE
:
2345 case BUILT_IN_MEMPCPY
:
2346 case BUILT_IN_STPCPY
:
2347 case BUILT_IN_STPNCPY
:
2348 case BUILT_IN_STRCAT
:
2349 case BUILT_IN_STRNCAT
:
2350 case BUILT_IN_MEMSET
:
2351 case BUILT_IN_TM_MEMSET
:
2352 CASE_BUILT_IN_TM_STORE (1):
2353 CASE_BUILT_IN_TM_STORE (2):
2354 CASE_BUILT_IN_TM_STORE (4):
2355 CASE_BUILT_IN_TM_STORE (8):
2356 CASE_BUILT_IN_TM_STORE (FLOAT
):
2357 CASE_BUILT_IN_TM_STORE (DOUBLE
):
2358 CASE_BUILT_IN_TM_STORE (LDOUBLE
):
2359 CASE_BUILT_IN_TM_STORE (M64
):
2360 CASE_BUILT_IN_TM_STORE (M128
):
2361 CASE_BUILT_IN_TM_STORE (M256
):
2362 case BUILT_IN_TM_MEMCPY
:
2363 case BUILT_IN_TM_MEMMOVE
:
2366 tree size
= NULL_TREE
;
2367 /* Don't pass in size for strncat, as the maximum size
2368 is strlen (dest) + n + 1 instead of n, resp.
2369 n + 1 at dest + strlen (dest), but strlen (dest) isn't
2371 if (gimple_call_num_args (call
) == 3
2372 && DECL_FUNCTION_CODE (callee
) != BUILT_IN_STRNCAT
)
2373 size
= gimple_call_arg (call
, 2);
2374 ao_ref_init_from_ptr_and_size (&dref
,
2375 gimple_call_arg (call
, 0),
2377 return refs_may_alias_p_1 (&dref
, ref
, false);
2379 case BUILT_IN_STRCPY_CHK
:
2380 case BUILT_IN_STRNCPY_CHK
:
2381 case BUILT_IN_MEMCPY_CHK
:
2382 case BUILT_IN_MEMMOVE_CHK
:
2383 case BUILT_IN_MEMPCPY_CHK
:
2384 case BUILT_IN_STPCPY_CHK
:
2385 case BUILT_IN_STPNCPY_CHK
:
2386 case BUILT_IN_STRCAT_CHK
:
2387 case BUILT_IN_STRNCAT_CHK
:
2388 case BUILT_IN_MEMSET_CHK
:
2391 tree size
= NULL_TREE
;
2392 /* Don't pass in size for __strncat_chk, as the maximum size
2393 is strlen (dest) + n + 1 instead of n, resp.
2394 n + 1 at dest + strlen (dest), but strlen (dest) isn't
2396 if (gimple_call_num_args (call
) == 4
2397 && DECL_FUNCTION_CODE (callee
) != BUILT_IN_STRNCAT_CHK
)
2398 size
= gimple_call_arg (call
, 2);
2399 ao_ref_init_from_ptr_and_size (&dref
,
2400 gimple_call_arg (call
, 0),
2402 return refs_may_alias_p_1 (&dref
, ref
, false);
2404 case BUILT_IN_BCOPY
:
2407 tree size
= gimple_call_arg (call
, 2);
2408 ao_ref_init_from_ptr_and_size (&dref
,
2409 gimple_call_arg (call
, 1),
2411 return refs_may_alias_p_1 (&dref
, ref
, false);
2413 /* Allocating memory does not have any side-effects apart from
2414 being the definition point for the pointer. */
2415 case BUILT_IN_MALLOC
:
2416 case BUILT_IN_ALIGNED_ALLOC
:
2417 case BUILT_IN_CALLOC
:
2418 case BUILT_IN_STRDUP
:
2419 case BUILT_IN_STRNDUP
:
2420 /* Unix98 specifies that errno is set on allocation failure. */
2422 && targetm
.ref_may_alias_errno (ref
))
2425 case BUILT_IN_STACK_SAVE
:
2426 CASE_BUILT_IN_ALLOCA
:
2427 case BUILT_IN_ASSUME_ALIGNED
:
2429 /* But posix_memalign stores a pointer into the memory pointed to
2430 by its first argument. */
2431 case BUILT_IN_POSIX_MEMALIGN
:
2433 tree ptrptr
= gimple_call_arg (call
, 0);
2435 ao_ref_init_from_ptr_and_size (&dref
, ptrptr
,
2436 TYPE_SIZE_UNIT (ptr_type_node
));
2437 return (refs_may_alias_p_1 (&dref
, ref
, false)
2439 && targetm
.ref_may_alias_errno (ref
)));
2441 /* Freeing memory kills the pointed-to memory. More importantly
2442 the call has to serve as a barrier for moving loads and stores
2445 case BUILT_IN_VA_END
:
2447 tree ptr
= gimple_call_arg (call
, 0);
2448 return ptr_deref_may_alias_ref_p_1 (ptr
, ref
);
2450 /* Realloc serves both as allocation point and deallocation point. */
2451 case BUILT_IN_REALLOC
:
2453 tree ptr
= gimple_call_arg (call
, 0);
2454 /* Unix98 specifies that errno is set on allocation failure. */
2455 return ((flag_errno_math
2456 && targetm
.ref_may_alias_errno (ref
))
2457 || ptr_deref_may_alias_ref_p_1 (ptr
, ref
));
2459 case BUILT_IN_GAMMA_R
:
2460 case BUILT_IN_GAMMAF_R
:
2461 case BUILT_IN_GAMMAL_R
:
2462 case BUILT_IN_LGAMMA_R
:
2463 case BUILT_IN_LGAMMAF_R
:
2464 case BUILT_IN_LGAMMAL_R
:
2466 tree out
= gimple_call_arg (call
, 1);
2467 if (ptr_deref_may_alias_ref_p_1 (out
, ref
))
2469 if (flag_errno_math
)
2473 case BUILT_IN_FREXP
:
2474 case BUILT_IN_FREXPF
:
2475 case BUILT_IN_FREXPL
:
2477 case BUILT_IN_MODFF
:
2478 case BUILT_IN_MODFL
:
2480 tree out
= gimple_call_arg (call
, 1);
2481 return ptr_deref_may_alias_ref_p_1 (out
, ref
);
2483 case BUILT_IN_REMQUO
:
2484 case BUILT_IN_REMQUOF
:
2485 case BUILT_IN_REMQUOL
:
2487 tree out
= gimple_call_arg (call
, 2);
2488 if (ptr_deref_may_alias_ref_p_1 (out
, ref
))
2490 if (flag_errno_math
)
2494 case BUILT_IN_SINCOS
:
2495 case BUILT_IN_SINCOSF
:
2496 case BUILT_IN_SINCOSL
:
2498 tree sin
= gimple_call_arg (call
, 1);
2499 tree cos
= gimple_call_arg (call
, 2);
2500 return (ptr_deref_may_alias_ref_p_1 (sin
, ref
)
2501 || ptr_deref_may_alias_ref_p_1 (cos
, ref
));
2503 /* __sync_* builtins and some OpenMP builtins act as threading
2505 #undef DEF_SYNC_BUILTIN
2506 #define DEF_SYNC_BUILTIN(ENUM, NAME, TYPE, ATTRS) case ENUM:
2507 #include "sync-builtins.def"
2508 #undef DEF_SYNC_BUILTIN
2509 case BUILT_IN_GOMP_ATOMIC_START
:
2510 case BUILT_IN_GOMP_ATOMIC_END
:
2511 case BUILT_IN_GOMP_BARRIER
:
2512 case BUILT_IN_GOMP_BARRIER_CANCEL
:
2513 case BUILT_IN_GOMP_TASKWAIT
:
2514 case BUILT_IN_GOMP_TASKGROUP_END
:
2515 case BUILT_IN_GOMP_CRITICAL_START
:
2516 case BUILT_IN_GOMP_CRITICAL_END
:
2517 case BUILT_IN_GOMP_CRITICAL_NAME_START
:
2518 case BUILT_IN_GOMP_CRITICAL_NAME_END
:
2519 case BUILT_IN_GOMP_LOOP_END
:
2520 case BUILT_IN_GOMP_LOOP_END_CANCEL
:
2521 case BUILT_IN_GOMP_ORDERED_START
:
2522 case BUILT_IN_GOMP_ORDERED_END
:
2523 case BUILT_IN_GOMP_SECTIONS_END
:
2524 case BUILT_IN_GOMP_SECTIONS_END_CANCEL
:
2525 case BUILT_IN_GOMP_SINGLE_COPY_START
:
2526 case BUILT_IN_GOMP_SINGLE_COPY_END
:
2529 /* Fallthru to general call handling. */;
2532 /* Check if base is a global static variable that is not written
2534 if (callee
!= NULL_TREE
&& VAR_P (base
) && TREE_STATIC (base
))
2536 struct cgraph_node
*node
= cgraph_node::get (callee
);
2540 && (not_written
= ipa_reference_get_not_written_global (node
))
2541 && bitmap_bit_p (not_written
, ipa_reference_var_uid (base
)))
2545 /* Check if the base variable is call-clobbered. */
2547 return pt_solution_includes (gimple_call_clobber_set (call
), base
);
2548 else if ((TREE_CODE (base
) == MEM_REF
2549 || TREE_CODE (base
) == TARGET_MEM_REF
)
2550 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
)
2552 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (TREE_OPERAND (base
, 0));
2556 return pt_solutions_intersect (gimple_call_clobber_set (call
), &pi
->pt
);
2562 /* If the call in statement CALL may clobber the memory reference REF
2563 return true, otherwise return false. */
2566 call_may_clobber_ref_p (gcall
*call
, tree ref
)
2570 ao_ref_init (&r
, ref
);
2571 res
= call_may_clobber_ref_p_1 (call
, &r
);
2573 ++alias_stats
.call_may_clobber_ref_p_may_alias
;
2575 ++alias_stats
.call_may_clobber_ref_p_no_alias
;
2580 /* If the statement STMT may clobber the memory reference REF return true,
2581 otherwise return false. */
2584 stmt_may_clobber_ref_p_1 (gimple
*stmt
, ao_ref
*ref
, bool tbaa_p
)
2586 if (is_gimple_call (stmt
))
2588 tree lhs
= gimple_call_lhs (stmt
);
2590 && TREE_CODE (lhs
) != SSA_NAME
)
2593 ao_ref_init (&r
, lhs
);
2594 if (refs_may_alias_p_1 (ref
, &r
, tbaa_p
))
2598 return call_may_clobber_ref_p_1 (as_a
<gcall
*> (stmt
), ref
);
2600 else if (gimple_assign_single_p (stmt
))
2602 tree lhs
= gimple_assign_lhs (stmt
);
2603 if (TREE_CODE (lhs
) != SSA_NAME
)
2606 ao_ref_init (&r
, lhs
);
2607 return refs_may_alias_p_1 (ref
, &r
, tbaa_p
);
2610 else if (gimple_code (stmt
) == GIMPLE_ASM
)
2617 stmt_may_clobber_ref_p (gimple
*stmt
, tree ref
, bool tbaa_p
)
2620 ao_ref_init (&r
, ref
);
2621 return stmt_may_clobber_ref_p_1 (stmt
, &r
, tbaa_p
);
2624 /* Return true if store1 and store2 described by corresponding tuples
2625 <BASE, OFFSET, SIZE, MAX_SIZE> have the same size and store to the same
2629 same_addr_size_stores_p (tree base1
, poly_int64 offset1
, poly_int64 size1
,
2630 poly_int64 max_size1
,
2631 tree base2
, poly_int64 offset2
, poly_int64 size2
,
2632 poly_int64 max_size2
)
2634 /* Offsets need to be 0. */
2635 if (maybe_ne (offset1
, 0)
2636 || maybe_ne (offset2
, 0))
2639 bool base1_obj_p
= SSA_VAR_P (base1
);
2640 bool base2_obj_p
= SSA_VAR_P (base2
);
2642 /* We need one object. */
2643 if (base1_obj_p
== base2_obj_p
)
2645 tree obj
= base1_obj_p
? base1
: base2
;
2647 /* And we need one MEM_REF. */
2648 bool base1_memref_p
= TREE_CODE (base1
) == MEM_REF
;
2649 bool base2_memref_p
= TREE_CODE (base2
) == MEM_REF
;
2650 if (base1_memref_p
== base2_memref_p
)
2652 tree memref
= base1_memref_p
? base1
: base2
;
2654 /* Sizes need to be valid. */
2655 if (!known_size_p (max_size1
)
2656 || !known_size_p (max_size2
)
2657 || !known_size_p (size1
)
2658 || !known_size_p (size2
))
2661 /* Max_size needs to match size. */
2662 if (maybe_ne (max_size1
, size1
)
2663 || maybe_ne (max_size2
, size2
))
2666 /* Sizes need to match. */
2667 if (maybe_ne (size1
, size2
))
2671 /* Check that memref is a store to pointer with singleton points-to info. */
2672 if (!integer_zerop (TREE_OPERAND (memref
, 1)))
2674 tree ptr
= TREE_OPERAND (memref
, 0);
2675 if (TREE_CODE (ptr
) != SSA_NAME
)
2677 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (ptr
);
2678 unsigned int pt_uid
;
2680 || !pt_solution_singleton_or_null_p (&pi
->pt
, &pt_uid
))
2683 /* Be conservative with non-call exceptions when the address might
2685 if (cfun
->can_throw_non_call_exceptions
&& pi
->pt
.null
)
2688 /* Check that ptr points relative to obj. */
2689 unsigned int obj_uid
= DECL_PT_UID (obj
);
2690 if (obj_uid
!= pt_uid
)
2693 /* Check that the object size is the same as the store size. That ensures us
2694 that ptr points to the start of obj. */
2695 return (DECL_SIZE (obj
)
2696 && poly_int_tree_p (DECL_SIZE (obj
))
2697 && known_eq (wi::to_poly_offset (DECL_SIZE (obj
)), size1
));
2700 /* If STMT kills the memory reference REF return true, otherwise
2704 stmt_kills_ref_p (gimple
*stmt
, ao_ref
*ref
)
2706 if (!ao_ref_base (ref
))
2709 if (gimple_has_lhs (stmt
)
2710 && TREE_CODE (gimple_get_lhs (stmt
)) != SSA_NAME
2711 /* The assignment is not necessarily carried out if it can throw
2712 and we can catch it in the current function where we could inspect
2714 ??? We only need to care about the RHS throwing. For aggregate
2715 assignments or similar calls and non-call exceptions the LHS
2716 might throw as well. */
2717 && !stmt_can_throw_internal (cfun
, stmt
))
2719 tree lhs
= gimple_get_lhs (stmt
);
2720 /* If LHS is literally a base of the access we are done. */
2723 tree base
= ref
->ref
;
2724 tree innermost_dropped_array_ref
= NULL_TREE
;
2725 if (handled_component_p (base
))
2727 tree saved_lhs0
= NULL_TREE
;
2728 if (handled_component_p (lhs
))
2730 saved_lhs0
= TREE_OPERAND (lhs
, 0);
2731 TREE_OPERAND (lhs
, 0) = integer_zero_node
;
2735 /* Just compare the outermost handled component, if
2736 they are equal we have found a possible common
2738 tree saved_base0
= TREE_OPERAND (base
, 0);
2739 TREE_OPERAND (base
, 0) = integer_zero_node
;
2740 bool res
= operand_equal_p (lhs
, base
, 0);
2741 TREE_OPERAND (base
, 0) = saved_base0
;
2744 /* Remember if we drop an array-ref that we need to
2745 double-check not being at struct end. */
2746 if (TREE_CODE (base
) == ARRAY_REF
2747 || TREE_CODE (base
) == ARRAY_RANGE_REF
)
2748 innermost_dropped_array_ref
= base
;
2749 /* Otherwise drop handled components of the access. */
2752 while (handled_component_p (base
));
2754 TREE_OPERAND (lhs
, 0) = saved_lhs0
;
2756 /* Finally check if the lhs has the same address and size as the
2757 base candidate of the access. Watch out if we have dropped
2758 an array-ref that was at struct end, this means ref->ref may
2759 be outside of the TYPE_SIZE of its base. */
2760 if ((! innermost_dropped_array_ref
2761 || ! array_at_struct_end_p (innermost_dropped_array_ref
))
2763 || (((TYPE_SIZE (TREE_TYPE (lhs
))
2764 == TYPE_SIZE (TREE_TYPE (base
)))
2765 || (TYPE_SIZE (TREE_TYPE (lhs
))
2766 && TYPE_SIZE (TREE_TYPE (base
))
2767 && operand_equal_p (TYPE_SIZE (TREE_TYPE (lhs
)),
2768 TYPE_SIZE (TREE_TYPE (base
)),
2770 && operand_equal_p (lhs
, base
,
2772 | OEP_MATCH_SIDE_EFFECTS
))))
2776 /* Now look for non-literal equal bases with the restriction of
2777 handling constant offset and size. */
2778 /* For a must-alias check we need to be able to constrain
2779 the access properly. */
2780 if (!ref
->max_size_known_p ())
2782 poly_int64 size
, offset
, max_size
, ref_offset
= ref
->offset
;
2784 tree base
= get_ref_base_and_extent (lhs
, &offset
, &size
, &max_size
,
2786 /* We can get MEM[symbol: sZ, index: D.8862_1] here,
2787 so base == ref->base does not always hold. */
2788 if (base
!= ref
->base
)
2790 /* Try using points-to info. */
2791 if (same_addr_size_stores_p (base
, offset
, size
, max_size
, ref
->base
,
2792 ref
->offset
, ref
->size
, ref
->max_size
))
2795 /* If both base and ref->base are MEM_REFs, only compare the
2796 first operand, and if the second operand isn't equal constant,
2797 try to add the offsets into offset and ref_offset. */
2798 if (TREE_CODE (base
) == MEM_REF
&& TREE_CODE (ref
->base
) == MEM_REF
2799 && TREE_OPERAND (base
, 0) == TREE_OPERAND (ref
->base
, 0))
2801 if (!tree_int_cst_equal (TREE_OPERAND (base
, 1),
2802 TREE_OPERAND (ref
->base
, 1)))
2804 poly_offset_int off1
= mem_ref_offset (base
);
2805 off1
<<= LOG2_BITS_PER_UNIT
;
2807 poly_offset_int off2
= mem_ref_offset (ref
->base
);
2808 off2
<<= LOG2_BITS_PER_UNIT
;
2810 if (!off1
.to_shwi (&offset
) || !off2
.to_shwi (&ref_offset
))
2817 /* For a must-alias check we need to be able to constrain
2818 the access properly. */
2819 if (known_eq (size
, max_size
)
2820 && known_subrange_p (ref_offset
, ref
->max_size
, offset
, size
))
2824 if (is_gimple_call (stmt
))
2826 tree callee
= gimple_call_fndecl (stmt
);
2827 if (callee
!= NULL_TREE
2828 && gimple_call_builtin_p (stmt
, BUILT_IN_NORMAL
))
2829 switch (DECL_FUNCTION_CODE (callee
))
2833 tree ptr
= gimple_call_arg (stmt
, 0);
2834 tree base
= ao_ref_base (ref
);
2835 if (base
&& TREE_CODE (base
) == MEM_REF
2836 && TREE_OPERAND (base
, 0) == ptr
)
2841 case BUILT_IN_MEMCPY
:
2842 case BUILT_IN_MEMPCPY
:
2843 case BUILT_IN_MEMMOVE
:
2844 case BUILT_IN_MEMSET
:
2845 case BUILT_IN_MEMCPY_CHK
:
2846 case BUILT_IN_MEMPCPY_CHK
:
2847 case BUILT_IN_MEMMOVE_CHK
:
2848 case BUILT_IN_MEMSET_CHK
:
2849 case BUILT_IN_STRNCPY
:
2850 case BUILT_IN_STPNCPY
:
2852 /* For a must-alias check we need to be able to constrain
2853 the access properly. */
2854 if (!ref
->max_size_known_p ())
2856 tree dest
= gimple_call_arg (stmt
, 0);
2857 tree len
= gimple_call_arg (stmt
, 2);
2858 if (!poly_int_tree_p (len
))
2860 tree rbase
= ref
->base
;
2861 poly_offset_int roffset
= ref
->offset
;
2863 ao_ref_init_from_ptr_and_size (&dref
, dest
, len
);
2864 tree base
= ao_ref_base (&dref
);
2865 poly_offset_int offset
= dref
.offset
;
2866 if (!base
|| !known_size_p (dref
.size
))
2868 if (TREE_CODE (base
) == MEM_REF
)
2870 if (TREE_CODE (rbase
) != MEM_REF
)
2872 // Compare pointers.
2873 offset
+= mem_ref_offset (base
) << LOG2_BITS_PER_UNIT
;
2874 roffset
+= mem_ref_offset (rbase
) << LOG2_BITS_PER_UNIT
;
2875 base
= TREE_OPERAND (base
, 0);
2876 rbase
= TREE_OPERAND (rbase
, 0);
2879 && known_subrange_p (roffset
, ref
->max_size
, offset
,
2880 wi::to_poly_offset (len
)
2881 << LOG2_BITS_PER_UNIT
))
2886 case BUILT_IN_VA_END
:
2888 tree ptr
= gimple_call_arg (stmt
, 0);
2889 if (TREE_CODE (ptr
) == ADDR_EXPR
)
2891 tree base
= ao_ref_base (ref
);
2892 if (TREE_OPERAND (ptr
, 0) == base
)
2905 stmt_kills_ref_p (gimple
*stmt
, tree ref
)
2908 ao_ref_init (&r
, ref
);
2909 return stmt_kills_ref_p (stmt
, &r
);
2913 /* Walk the virtual use-def chain of VUSE until hitting the virtual operand
2914 TARGET or a statement clobbering the memory reference REF in which
2915 case false is returned. The walk starts with VUSE, one argument of PHI. */
2918 maybe_skip_until (gimple
*phi
, tree
&target
, basic_block target_bb
,
2919 ao_ref
*ref
, tree vuse
, unsigned int &limit
, bitmap
*visited
,
2920 bool abort_on_visited
,
2921 void *(*translate
)(ao_ref
*, tree
, void *, bool *),
2924 basic_block bb
= gimple_bb (phi
);
2927 *visited
= BITMAP_ALLOC (NULL
);
2929 bitmap_set_bit (*visited
, SSA_NAME_VERSION (PHI_RESULT (phi
)));
2931 /* Walk until we hit the target. */
2932 while (vuse
!= target
)
2934 gimple
*def_stmt
= SSA_NAME_DEF_STMT (vuse
);
2935 /* If we are searching for the target VUSE by walking up to
2936 TARGET_BB dominating the original PHI we are finished once
2937 we reach a default def or a definition in a block dominating
2938 that block. Update TARGET and return. */
2940 && (gimple_nop_p (def_stmt
)
2941 || dominated_by_p (CDI_DOMINATORS
,
2942 target_bb
, gimple_bb (def_stmt
))))
2948 /* Recurse for PHI nodes. */
2949 if (gimple_code (def_stmt
) == GIMPLE_PHI
)
2951 /* An already visited PHI node ends the walk successfully. */
2952 if (bitmap_bit_p (*visited
, SSA_NAME_VERSION (PHI_RESULT (def_stmt
))))
2953 return !abort_on_visited
;
2954 vuse
= get_continuation_for_phi (def_stmt
, ref
, limit
,
2955 visited
, abort_on_visited
,
2961 else if (gimple_nop_p (def_stmt
))
2965 /* A clobbering statement or the end of the IL ends it failing. */
2966 if ((int)limit
<= 0)
2969 if (stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
2971 bool disambiguate_only
= true;
2973 && (*translate
) (ref
, vuse
, data
, &disambiguate_only
) == NULL
)
2979 /* If we reach a new basic-block see if we already skipped it
2980 in a previous walk that ended successfully. */
2981 if (gimple_bb (def_stmt
) != bb
)
2983 if (!bitmap_set_bit (*visited
, SSA_NAME_VERSION (vuse
)))
2984 return !abort_on_visited
;
2985 bb
= gimple_bb (def_stmt
);
2987 vuse
= gimple_vuse (def_stmt
);
2993 /* Starting from a PHI node for the virtual operand of the memory reference
2994 REF find a continuation virtual operand that allows to continue walking
2995 statements dominating PHI skipping only statements that cannot possibly
2996 clobber REF. Decrements LIMIT for each alias disambiguation done
2997 and aborts the walk, returning NULL_TREE if it reaches zero.
2998 Returns NULL_TREE if no suitable virtual operand can be found. */
3001 get_continuation_for_phi (gimple
*phi
, ao_ref
*ref
,
3002 unsigned int &limit
, bitmap
*visited
,
3003 bool abort_on_visited
,
3004 void *(*translate
)(ao_ref
*, tree
, void *, bool *),
3007 unsigned nargs
= gimple_phi_num_args (phi
);
3009 /* Through a single-argument PHI we can simply look through. */
3011 return PHI_ARG_DEF (phi
, 0);
3013 /* For two or more arguments try to pairwise skip non-aliasing code
3014 until we hit the phi argument definition that dominates the other one. */
3015 basic_block phi_bb
= gimple_bb (phi
);
3019 /* Find a candidate for the virtual operand which definition
3020 dominates those of all others. */
3021 /* First look if any of the args themselves satisfy this. */
3022 for (i
= 0; i
< nargs
; ++i
)
3024 arg0
= PHI_ARG_DEF (phi
, i
);
3025 if (SSA_NAME_IS_DEFAULT_DEF (arg0
))
3027 basic_block def_bb
= gimple_bb (SSA_NAME_DEF_STMT (arg0
));
3028 if (def_bb
!= phi_bb
3029 && dominated_by_p (CDI_DOMINATORS
, phi_bb
, def_bb
))
3033 /* If not, look if we can reach such candidate by walking defs
3034 until we hit the immediate dominator. maybe_skip_until will
3036 basic_block dom
= get_immediate_dominator (CDI_DOMINATORS
, phi_bb
);
3038 /* Then check against the (to be) found candidate. */
3039 for (i
= 0; i
< nargs
; ++i
)
3041 arg1
= PHI_ARG_DEF (phi
, i
);
3044 else if (! maybe_skip_until (phi
, arg0
, dom
, ref
, arg1
, limit
, visited
,
3046 /* Do not translate when walking over
3050 gimple_bb (SSA_NAME_DEF_STMT (arg1
)),
3052 ? NULL
: translate
, data
))
3059 /* Based on the memory reference REF and its virtual use VUSE call
3060 WALKER for each virtual use that is equivalent to VUSE, including VUSE
3061 itself. That is, for each virtual use for which its defining statement
3062 does not clobber REF.
3064 WALKER is called with REF, the current virtual use and DATA. If
3065 WALKER returns non-NULL the walk stops and its result is returned.
3066 At the end of a non-successful walk NULL is returned.
3068 TRANSLATE if non-NULL is called with a pointer to REF, the virtual
3069 use which definition is a statement that may clobber REF and DATA.
3070 If TRANSLATE returns (void *)-1 the walk stops and NULL is returned.
3071 If TRANSLATE returns non-NULL the walk stops and its result is returned.
3072 If TRANSLATE returns NULL the walk continues and TRANSLATE is supposed
3073 to adjust REF and *DATA to make that valid.
3075 VALUEIZE if non-NULL is called with the next VUSE that is considered
3076 and return value is substituted for that. This can be used to
3077 implement optimistic value-numbering for example. Note that the
3078 VUSE argument is assumed to be valueized already.
3080 LIMIT specifies the number of alias queries we are allowed to do,
3081 the walk stops when it reaches zero and NULL is returned. LIMIT
3082 is decremented by the number of alias queries (plus adjustments
3083 done by the callbacks) upon return.
3085 TODO: Cache the vector of equivalent vuses per ref, vuse pair. */
3088 walk_non_aliased_vuses (ao_ref
*ref
, tree vuse
,
3089 void *(*walker
)(ao_ref
*, tree
, void *),
3090 void *(*translate
)(ao_ref
*, tree
, void *, bool *),
3091 tree (*valueize
)(tree
),
3092 unsigned &limit
, void *data
)
3094 bitmap visited
= NULL
;
3096 bool translated
= false;
3098 timevar_push (TV_ALIAS_STMT_WALK
);
3104 /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */
3105 res
= (*walker
) (ref
, vuse
, data
);
3107 if (res
== (void *)-1)
3112 /* Lookup succeeded. */
3113 else if (res
!= NULL
)
3118 vuse
= valueize (vuse
);
3125 def_stmt
= SSA_NAME_DEF_STMT (vuse
);
3126 if (gimple_nop_p (def_stmt
))
3128 else if (gimple_code (def_stmt
) == GIMPLE_PHI
)
3129 vuse
= get_continuation_for_phi (def_stmt
, ref
, limit
,
3130 &visited
, translated
, translate
, data
);
3133 if ((int)limit
<= 0)
3139 if (stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
3143 bool disambiguate_only
= false;
3144 res
= (*translate
) (ref
, vuse
, data
, &disambiguate_only
);
3145 /* Failed lookup and translation. */
3146 if (res
== (void *)-1)
3151 /* Lookup succeeded. */
3152 else if (res
!= NULL
)
3154 /* Translation succeeded, continue walking. */
3155 translated
= translated
|| !disambiguate_only
;
3157 vuse
= gimple_vuse (def_stmt
);
3163 BITMAP_FREE (visited
);
3165 timevar_pop (TV_ALIAS_STMT_WALK
);
3171 /* Based on the memory reference REF call WALKER for each vdef which
3172 defining statement may clobber REF, starting with VDEF. If REF
3173 is NULL_TREE, each defining statement is visited.
3175 WALKER is called with REF, the current vdef and DATA. If WALKER
3176 returns true the walk is stopped, otherwise it continues.
3178 If function entry is reached, FUNCTION_ENTRY_REACHED is set to true.
3179 The pointer may be NULL and then we do not track this information.
3181 At PHI nodes walk_aliased_vdefs forks into one walk for reach
3182 PHI argument (but only one walk continues on merge points), the
3183 return value is true if any of the walks was successful.
3185 The function returns the number of statements walked or -1 if
3186 LIMIT stmts were walked and the walk was aborted at this point.
3187 If LIMIT is zero the walk is not aborted. */
3190 walk_aliased_vdefs_1 (ao_ref
*ref
, tree vdef
,
3191 bool (*walker
)(ao_ref
*, tree
, void *), void *data
,
3192 bitmap
*visited
, unsigned int cnt
,
3193 bool *function_entry_reached
, unsigned limit
)
3197 gimple
*def_stmt
= SSA_NAME_DEF_STMT (vdef
);
3200 && !bitmap_set_bit (*visited
, SSA_NAME_VERSION (vdef
)))
3203 if (gimple_nop_p (def_stmt
))
3205 if (function_entry_reached
)
3206 *function_entry_reached
= true;
3209 else if (gimple_code (def_stmt
) == GIMPLE_PHI
)
3213 *visited
= BITMAP_ALLOC (NULL
);
3214 for (i
= 0; i
< gimple_phi_num_args (def_stmt
); ++i
)
3216 int res
= walk_aliased_vdefs_1 (ref
,
3217 gimple_phi_arg_def (def_stmt
, i
),
3218 walker
, data
, visited
, cnt
,
3219 function_entry_reached
, limit
);
3227 /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */
3232 || stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
3233 && (*walker
) (ref
, vdef
, data
))
3236 vdef
= gimple_vuse (def_stmt
);
3242 walk_aliased_vdefs (ao_ref
*ref
, tree vdef
,
3243 bool (*walker
)(ao_ref
*, tree
, void *), void *data
,
3245 bool *function_entry_reached
, unsigned int limit
)
3247 bitmap local_visited
= NULL
;
3250 timevar_push (TV_ALIAS_STMT_WALK
);
3252 if (function_entry_reached
)
3253 *function_entry_reached
= false;
3255 ret
= walk_aliased_vdefs_1 (ref
, vdef
, walker
, data
,
3256 visited
? visited
: &local_visited
, 0,
3257 function_entry_reached
, limit
);
3259 BITMAP_FREE (local_visited
);
3261 timevar_pop (TV_ALIAS_STMT_WALK
);