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 /* If the alias set for a pointer access is zero all bets are off. */
1462 if (base1_alias_set
== 0 || base2_alias_set
== 0)
1465 /* When we are trying to disambiguate an access with a pointer dereference
1466 as base versus one with a decl as base we can use both the size
1467 of the decl and its dynamic type for extra disambiguation.
1468 ??? We do not know anything about the dynamic type of the decl
1469 other than that its alias-set contains base2_alias_set as a subset
1470 which does not help us here. */
1471 /* As we know nothing useful about the dynamic type of the decl just
1472 use the usual conflict check rather than a subset test.
1473 ??? We could introduce -fvery-strict-aliasing when the language
1474 does not allow decls to have a dynamic type that differs from their
1475 static type. Then we can check
1476 !alias_set_subset_of (base1_alias_set, base2_alias_set) instead. */
1477 if (base1_alias_set
!= base2_alias_set
1478 && !alias_sets_conflict_p (base1_alias_set
, base2_alias_set
))
1481 ptrtype1
= TREE_TYPE (TREE_OPERAND (base1
, 1));
1483 /* If the size of the access relevant for TBAA through the pointer
1484 is bigger than the size of the decl we can't possibly access the
1485 decl via that pointer. */
1486 if (/* ??? This in turn may run afoul when a decl of type T which is
1487 a member of union type U is accessed through a pointer to
1488 type U and sizeof T is smaller than sizeof U. */
1489 TREE_CODE (TREE_TYPE (ptrtype1
)) != UNION_TYPE
1490 && TREE_CODE (TREE_TYPE (ptrtype1
)) != QUAL_UNION_TYPE
1491 && compare_sizes (DECL_SIZE (base2
),
1492 TYPE_SIZE (TREE_TYPE (ptrtype1
))) < 0)
1498 /* If the decl is accessed via a MEM_REF, reconstruct the base
1499 we can use for TBAA and an appropriately adjusted offset. */
1501 while (handled_component_p (dbase2
))
1502 dbase2
= TREE_OPERAND (dbase2
, 0);
1503 poly_int64 doffset1
= offset1
;
1504 poly_offset_int doffset2
= offset2
;
1505 if (TREE_CODE (dbase2
) == MEM_REF
1506 || TREE_CODE (dbase2
) == TARGET_MEM_REF
)
1508 doffset2
-= mem_ref_offset (dbase2
) << LOG2_BITS_PER_UNIT
;
1509 tree ptrtype2
= TREE_TYPE (TREE_OPERAND (dbase2
, 1));
1510 /* If second reference is view-converted, give up now. */
1511 if (same_type_for_tbaa (TREE_TYPE (dbase2
), TREE_TYPE (ptrtype2
)) != 1)
1515 /* If first reference is view-converted, give up now. */
1516 if (same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (ptrtype1
)) != 1)
1519 /* If both references are through the same type, they do not alias
1520 if the accesses do not overlap. This does extra disambiguation
1521 for mixed/pointer accesses but requires strict aliasing.
1522 For MEM_REFs we require that the component-ref offset we computed
1523 is relative to the start of the type which we ensure by
1524 comparing rvalue and access type and disregarding the constant
1527 But avoid treating variable length arrays as "objects", instead assume they
1528 can overlap by an exact multiple of their element size.
1529 See gcc.dg/torture/alias-2.c. */
1530 if (((TREE_CODE (base1
) != TARGET_MEM_REF
1531 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1532 && (TREE_CODE (dbase2
) != TARGET_MEM_REF
1533 || (!TMR_INDEX (dbase2
) && !TMR_INDEX2 (dbase2
))))
1534 && same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (dbase2
)) == 1
1535 && (TREE_CODE (TREE_TYPE (base1
)) != ARRAY_TYPE
1536 || (TYPE_SIZE (TREE_TYPE (base1
))
1537 && TREE_CODE (TYPE_SIZE (TREE_TYPE (base1
))) == INTEGER_CST
)))
1538 return ranges_maybe_overlap_p (doffset1
, max_size1
, doffset2
, max_size2
);
1541 && nonoverlapping_component_refs_p (ref1
, ref2
))
1544 /* Do access-path based disambiguation. */
1546 && (handled_component_p (ref1
) || handled_component_p (ref2
)))
1547 return aliasing_component_refs_p (ref1
,
1548 ref1_alias_set
, base1_alias_set
,
1551 ref2_alias_set
, base2_alias_set
,
1552 offset2
, max_size2
);
1557 /* Return true if two indirect references based on *PTR1
1558 and *PTR2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and
1559 [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. *PTR1 and *PTR2 have
1560 the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1
1561 in which case they are computed on-demand. REF1 and REF2
1562 if non-NULL are the complete memory reference trees. */
1565 indirect_refs_may_alias_p (tree ref1 ATTRIBUTE_UNUSED
, tree base1
,
1566 poly_int64 offset1
, poly_int64 max_size1
,
1567 alias_set_type ref1_alias_set
,
1568 alias_set_type base1_alias_set
,
1569 tree ref2 ATTRIBUTE_UNUSED
, tree base2
,
1570 poly_int64 offset2
, poly_int64 max_size2
,
1571 alias_set_type ref2_alias_set
,
1572 alias_set_type base2_alias_set
, bool tbaa_p
)
1576 tree ptrtype1
, ptrtype2
;
1578 gcc_checking_assert ((TREE_CODE (base1
) == MEM_REF
1579 || TREE_CODE (base1
) == TARGET_MEM_REF
)
1580 && (TREE_CODE (base2
) == MEM_REF
1581 || TREE_CODE (base2
) == TARGET_MEM_REF
));
1583 ptr1
= TREE_OPERAND (base1
, 0);
1584 ptr2
= TREE_OPERAND (base2
, 0);
1586 /* If both bases are based on pointers they cannot alias if they may not
1587 point to the same memory object or if they point to the same object
1588 and the accesses do not overlap. */
1589 if ((!cfun
|| gimple_in_ssa_p (cfun
))
1590 && operand_equal_p (ptr1
, ptr2
, 0)
1591 && (((TREE_CODE (base1
) != TARGET_MEM_REF
1592 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1593 && (TREE_CODE (base2
) != TARGET_MEM_REF
1594 || (!TMR_INDEX (base2
) && !TMR_INDEX2 (base2
))))
1595 || (TREE_CODE (base1
) == TARGET_MEM_REF
1596 && TREE_CODE (base2
) == TARGET_MEM_REF
1597 && (TMR_STEP (base1
) == TMR_STEP (base2
)
1598 || (TMR_STEP (base1
) && TMR_STEP (base2
)
1599 && operand_equal_p (TMR_STEP (base1
),
1600 TMR_STEP (base2
), 0)))
1601 && (TMR_INDEX (base1
) == TMR_INDEX (base2
)
1602 || (TMR_INDEX (base1
) && TMR_INDEX (base2
)
1603 && operand_equal_p (TMR_INDEX (base1
),
1604 TMR_INDEX (base2
), 0)))
1605 && (TMR_INDEX2 (base1
) == TMR_INDEX2 (base2
)
1606 || (TMR_INDEX2 (base1
) && TMR_INDEX2 (base2
)
1607 && operand_equal_p (TMR_INDEX2 (base1
),
1608 TMR_INDEX2 (base2
), 0))))))
1610 poly_offset_int moff1
= mem_ref_offset (base1
) << LOG2_BITS_PER_UNIT
;
1611 poly_offset_int moff2
= mem_ref_offset (base2
) << LOG2_BITS_PER_UNIT
;
1612 return ranges_maybe_overlap_p (offset1
+ moff1
, max_size1
,
1613 offset2
+ moff2
, max_size2
);
1615 if (!ptr_derefs_may_alias_p (ptr1
, ptr2
))
1618 /* Disambiguations that rely on strict aliasing rules follow. */
1619 if (!flag_strict_aliasing
|| !tbaa_p
)
1622 ptrtype1
= TREE_TYPE (TREE_OPERAND (base1
, 1));
1623 ptrtype2
= TREE_TYPE (TREE_OPERAND (base2
, 1));
1625 /* If the alias set for a pointer access is zero all bets are off. */
1626 if (base1_alias_set
== 0
1627 || base2_alias_set
== 0)
1630 /* Do type-based disambiguation. */
1631 if (base1_alias_set
!= base2_alias_set
1632 && !alias_sets_conflict_p (base1_alias_set
, base2_alias_set
))
1635 /* If either reference is view-converted, give up now. */
1636 if (same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (ptrtype1
)) != 1
1637 || same_type_for_tbaa (TREE_TYPE (base2
), TREE_TYPE (ptrtype2
)) != 1)
1640 /* If both references are through the same type, they do not alias
1641 if the accesses do not overlap. This does extra disambiguation
1642 for mixed/pointer accesses but requires strict aliasing. */
1643 if ((TREE_CODE (base1
) != TARGET_MEM_REF
1644 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1645 && (TREE_CODE (base2
) != TARGET_MEM_REF
1646 || (!TMR_INDEX (base2
) && !TMR_INDEX2 (base2
)))
1647 && same_type_for_tbaa (TREE_TYPE (ptrtype1
),
1648 TREE_TYPE (ptrtype2
)) == 1
1649 /* But avoid treating arrays as "objects", instead assume they
1650 can overlap by an exact multiple of their element size.
1651 See gcc.dg/torture/alias-2.c. */
1652 && TREE_CODE (TREE_TYPE (ptrtype1
)) != ARRAY_TYPE
)
1653 return ranges_maybe_overlap_p (offset1
, max_size1
, offset2
, max_size2
);
1656 && nonoverlapping_component_refs_p (ref1
, ref2
))
1659 /* Do access-path based disambiguation. */
1661 && (handled_component_p (ref1
) || handled_component_p (ref2
)))
1662 return aliasing_component_refs_p (ref1
,
1663 ref1_alias_set
, base1_alias_set
,
1666 ref2_alias_set
, base2_alias_set
,
1667 offset2
, max_size2
);
1672 /* Return true, if the two memory references REF1 and REF2 may alias. */
1675 refs_may_alias_p_2 (ao_ref
*ref1
, ao_ref
*ref2
, bool tbaa_p
)
1678 poly_int64 offset1
= 0, offset2
= 0;
1679 poly_int64 max_size1
= -1, max_size2
= -1;
1680 bool var1_p
, var2_p
, ind1_p
, ind2_p
;
1682 gcc_checking_assert ((!ref1
->ref
1683 || TREE_CODE (ref1
->ref
) == SSA_NAME
1684 || DECL_P (ref1
->ref
)
1685 || TREE_CODE (ref1
->ref
) == STRING_CST
1686 || handled_component_p (ref1
->ref
)
1687 || TREE_CODE (ref1
->ref
) == MEM_REF
1688 || TREE_CODE (ref1
->ref
) == TARGET_MEM_REF
)
1690 || TREE_CODE (ref2
->ref
) == SSA_NAME
1691 || DECL_P (ref2
->ref
)
1692 || TREE_CODE (ref2
->ref
) == STRING_CST
1693 || handled_component_p (ref2
->ref
)
1694 || TREE_CODE (ref2
->ref
) == MEM_REF
1695 || TREE_CODE (ref2
->ref
) == TARGET_MEM_REF
));
1697 /* Decompose the references into their base objects and the access. */
1698 base1
= ao_ref_base (ref1
);
1699 offset1
= ref1
->offset
;
1700 max_size1
= ref1
->max_size
;
1701 base2
= ao_ref_base (ref2
);
1702 offset2
= ref2
->offset
;
1703 max_size2
= ref2
->max_size
;
1705 /* We can end up with registers or constants as bases for example from
1706 *D.1663_44 = VIEW_CONVERT_EXPR<struct DB_LSN>(__tmp$B0F64_59);
1707 which is seen as a struct copy. */
1708 if (TREE_CODE (base1
) == SSA_NAME
1709 || TREE_CODE (base1
) == CONST_DECL
1710 || TREE_CODE (base1
) == CONSTRUCTOR
1711 || TREE_CODE (base1
) == ADDR_EXPR
1712 || CONSTANT_CLASS_P (base1
)
1713 || TREE_CODE (base2
) == SSA_NAME
1714 || TREE_CODE (base2
) == CONST_DECL
1715 || TREE_CODE (base2
) == CONSTRUCTOR
1716 || TREE_CODE (base2
) == ADDR_EXPR
1717 || CONSTANT_CLASS_P (base2
))
1720 /* We can end up referring to code via function and label decls.
1721 As we likely do not properly track code aliases conservatively
1723 if (TREE_CODE (base1
) == FUNCTION_DECL
1724 || TREE_CODE (base1
) == LABEL_DECL
1725 || TREE_CODE (base2
) == FUNCTION_DECL
1726 || TREE_CODE (base2
) == LABEL_DECL
)
1729 /* Two volatile accesses always conflict. */
1730 if (ref1
->volatile_p
1731 && ref2
->volatile_p
)
1734 /* Defer to simple offset based disambiguation if we have
1735 references based on two decls. Do this before defering to
1736 TBAA to handle must-alias cases in conformance with the
1737 GCC extension of allowing type-punning through unions. */
1738 var1_p
= DECL_P (base1
);
1739 var2_p
= DECL_P (base2
);
1740 if (var1_p
&& var2_p
)
1741 return decl_refs_may_alias_p (ref1
->ref
, base1
, offset1
, max_size1
,
1742 ref2
->ref
, base2
, offset2
, max_size2
);
1744 /* Handle restrict based accesses.
1745 ??? ao_ref_base strips inner MEM_REF [&decl], recover from that
1747 tree rbase1
= base1
;
1748 tree rbase2
= base2
;
1753 while (handled_component_p (rbase1
))
1754 rbase1
= TREE_OPERAND (rbase1
, 0);
1760 while (handled_component_p (rbase2
))
1761 rbase2
= TREE_OPERAND (rbase2
, 0);
1763 if (rbase1
&& rbase2
1764 && (TREE_CODE (base1
) == MEM_REF
|| TREE_CODE (base1
) == TARGET_MEM_REF
)
1765 && (TREE_CODE (base2
) == MEM_REF
|| TREE_CODE (base2
) == TARGET_MEM_REF
)
1766 /* If the accesses are in the same restrict clique... */
1767 && MR_DEPENDENCE_CLIQUE (base1
) == MR_DEPENDENCE_CLIQUE (base2
)
1768 /* But based on different pointers they do not alias. */
1769 && MR_DEPENDENCE_BASE (base1
) != MR_DEPENDENCE_BASE (base2
))
1772 ind1_p
= (TREE_CODE (base1
) == MEM_REF
1773 || TREE_CODE (base1
) == TARGET_MEM_REF
);
1774 ind2_p
= (TREE_CODE (base2
) == MEM_REF
1775 || TREE_CODE (base2
) == TARGET_MEM_REF
);
1777 /* Canonicalize the pointer-vs-decl case. */
1778 if (ind1_p
&& var2_p
)
1780 std::swap (offset1
, offset2
);
1781 std::swap (max_size1
, max_size2
);
1782 std::swap (base1
, base2
);
1783 std::swap (ref1
, ref2
);
1790 /* First defer to TBAA if possible. */
1792 && flag_strict_aliasing
1793 && !alias_sets_conflict_p (ao_ref_alias_set (ref1
),
1794 ao_ref_alias_set (ref2
)))
1797 /* If the reference is based on a pointer that points to memory
1798 that may not be written to then the other reference cannot possibly
1800 if ((TREE_CODE (TREE_OPERAND (base2
, 0)) == SSA_NAME
1801 && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base2
, 0)))
1803 && TREE_CODE (TREE_OPERAND (base1
, 0)) == SSA_NAME
1804 && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base1
, 0))))
1807 /* Dispatch to the pointer-vs-decl or pointer-vs-pointer disambiguators. */
1808 if (var1_p
&& ind2_p
)
1809 return indirect_ref_may_alias_decl_p (ref2
->ref
, base2
,
1811 ao_ref_alias_set (ref2
),
1812 ao_ref_base_alias_set (ref2
),
1815 ao_ref_alias_set (ref1
),
1816 ao_ref_base_alias_set (ref1
),
1818 else if (ind1_p
&& ind2_p
)
1819 return indirect_refs_may_alias_p (ref1
->ref
, base1
,
1821 ao_ref_alias_set (ref1
),
1822 ao_ref_base_alias_set (ref1
),
1825 ao_ref_alias_set (ref2
),
1826 ao_ref_base_alias_set (ref2
),
1832 /* Return true, if the two memory references REF1 and REF2 may alias
1833 and update statistics. */
1836 refs_may_alias_p_1 (ao_ref
*ref1
, ao_ref
*ref2
, bool tbaa_p
)
1838 bool res
= refs_may_alias_p_2 (ref1
, ref2
, tbaa_p
);
1840 ++alias_stats
.refs_may_alias_p_may_alias
;
1842 ++alias_stats
.refs_may_alias_p_no_alias
;
1847 refs_may_alias_p (tree ref1
, ao_ref
*ref2
, bool tbaa_p
)
1850 ao_ref_init (&r1
, ref1
);
1851 return refs_may_alias_p_1 (&r1
, ref2
, tbaa_p
);
1855 refs_may_alias_p (tree ref1
, tree ref2
, bool tbaa_p
)
1858 ao_ref_init (&r1
, ref1
);
1859 ao_ref_init (&r2
, ref2
);
1860 return refs_may_alias_p_1 (&r1
, &r2
, tbaa_p
);
1863 /* Returns true if there is a anti-dependence for the STORE that
1864 executes after the LOAD. */
1867 refs_anti_dependent_p (tree load
, tree store
)
1870 ao_ref_init (&r1
, load
);
1871 ao_ref_init (&r2
, store
);
1872 return refs_may_alias_p_1 (&r1
, &r2
, false);
1875 /* Returns true if there is a output dependence for the stores
1876 STORE1 and STORE2. */
1879 refs_output_dependent_p (tree store1
, tree store2
)
1882 ao_ref_init (&r1
, store1
);
1883 ao_ref_init (&r2
, store2
);
1884 return refs_may_alias_p_1 (&r1
, &r2
, false);
1887 /* If the call CALL may use the memory reference REF return true,
1888 otherwise return false. */
1891 ref_maybe_used_by_call_p_1 (gcall
*call
, ao_ref
*ref
, bool tbaa_p
)
1895 int flags
= gimple_call_flags (call
);
1897 /* Const functions without a static chain do not implicitly use memory. */
1898 if (!gimple_call_chain (call
)
1899 && (flags
& (ECF_CONST
|ECF_NOVOPS
)))
1902 base
= ao_ref_base (ref
);
1906 /* A call that is not without side-effects might involve volatile
1907 accesses and thus conflicts with all other volatile accesses. */
1908 if (ref
->volatile_p
)
1911 /* If the reference is based on a decl that is not aliased the call
1912 cannot possibly use it. */
1914 && !may_be_aliased (base
)
1915 /* But local statics can be used through recursion. */
1916 && !is_global_var (base
))
1919 callee
= gimple_call_fndecl (call
);
1921 /* Handle those builtin functions explicitly that do not act as
1922 escape points. See tree-ssa-structalias.c:find_func_aliases
1923 for the list of builtins we might need to handle here. */
1924 if (callee
!= NULL_TREE
1925 && gimple_call_builtin_p (call
, BUILT_IN_NORMAL
))
1926 switch (DECL_FUNCTION_CODE (callee
))
1928 /* All the following functions read memory pointed to by
1929 their second argument. strcat/strncat additionally
1930 reads memory pointed to by the first argument. */
1931 case BUILT_IN_STRCAT
:
1932 case BUILT_IN_STRNCAT
:
1935 ao_ref_init_from_ptr_and_size (&dref
,
1936 gimple_call_arg (call
, 0),
1938 if (refs_may_alias_p_1 (&dref
, ref
, false))
1942 case BUILT_IN_STRCPY
:
1943 case BUILT_IN_STRNCPY
:
1944 case BUILT_IN_MEMCPY
:
1945 case BUILT_IN_MEMMOVE
:
1946 case BUILT_IN_MEMPCPY
:
1947 case BUILT_IN_STPCPY
:
1948 case BUILT_IN_STPNCPY
:
1949 case BUILT_IN_TM_MEMCPY
:
1950 case BUILT_IN_TM_MEMMOVE
:
1953 tree size
= NULL_TREE
;
1954 if (gimple_call_num_args (call
) == 3)
1955 size
= gimple_call_arg (call
, 2);
1956 ao_ref_init_from_ptr_and_size (&dref
,
1957 gimple_call_arg (call
, 1),
1959 return refs_may_alias_p_1 (&dref
, ref
, false);
1961 case BUILT_IN_STRCAT_CHK
:
1962 case BUILT_IN_STRNCAT_CHK
:
1965 ao_ref_init_from_ptr_and_size (&dref
,
1966 gimple_call_arg (call
, 0),
1968 if (refs_may_alias_p_1 (&dref
, ref
, false))
1972 case BUILT_IN_STRCPY_CHK
:
1973 case BUILT_IN_STRNCPY_CHK
:
1974 case BUILT_IN_MEMCPY_CHK
:
1975 case BUILT_IN_MEMMOVE_CHK
:
1976 case BUILT_IN_MEMPCPY_CHK
:
1977 case BUILT_IN_STPCPY_CHK
:
1978 case BUILT_IN_STPNCPY_CHK
:
1981 tree size
= NULL_TREE
;
1982 if (gimple_call_num_args (call
) == 4)
1983 size
= gimple_call_arg (call
, 2);
1984 ao_ref_init_from_ptr_and_size (&dref
,
1985 gimple_call_arg (call
, 1),
1987 return refs_may_alias_p_1 (&dref
, ref
, false);
1989 case BUILT_IN_BCOPY
:
1992 tree size
= gimple_call_arg (call
, 2);
1993 ao_ref_init_from_ptr_and_size (&dref
,
1994 gimple_call_arg (call
, 0),
1996 return refs_may_alias_p_1 (&dref
, ref
, false);
1999 /* The following functions read memory pointed to by their
2001 CASE_BUILT_IN_TM_LOAD (1):
2002 CASE_BUILT_IN_TM_LOAD (2):
2003 CASE_BUILT_IN_TM_LOAD (4):
2004 CASE_BUILT_IN_TM_LOAD (8):
2005 CASE_BUILT_IN_TM_LOAD (FLOAT
):
2006 CASE_BUILT_IN_TM_LOAD (DOUBLE
):
2007 CASE_BUILT_IN_TM_LOAD (LDOUBLE
):
2008 CASE_BUILT_IN_TM_LOAD (M64
):
2009 CASE_BUILT_IN_TM_LOAD (M128
):
2010 CASE_BUILT_IN_TM_LOAD (M256
):
2011 case BUILT_IN_TM_LOG
:
2012 case BUILT_IN_TM_LOG_1
:
2013 case BUILT_IN_TM_LOG_2
:
2014 case BUILT_IN_TM_LOG_4
:
2015 case BUILT_IN_TM_LOG_8
:
2016 case BUILT_IN_TM_LOG_FLOAT
:
2017 case BUILT_IN_TM_LOG_DOUBLE
:
2018 case BUILT_IN_TM_LOG_LDOUBLE
:
2019 case BUILT_IN_TM_LOG_M64
:
2020 case BUILT_IN_TM_LOG_M128
:
2021 case BUILT_IN_TM_LOG_M256
:
2022 return ptr_deref_may_alias_ref_p_1 (gimple_call_arg (call
, 0), ref
);
2024 /* These read memory pointed to by the first argument. */
2025 case BUILT_IN_STRDUP
:
2026 case BUILT_IN_STRNDUP
:
2027 case BUILT_IN_REALLOC
:
2030 tree size
= NULL_TREE
;
2031 if (gimple_call_num_args (call
) == 2)
2032 size
= gimple_call_arg (call
, 1);
2033 ao_ref_init_from_ptr_and_size (&dref
,
2034 gimple_call_arg (call
, 0),
2036 return refs_may_alias_p_1 (&dref
, ref
, false);
2038 /* These read memory pointed to by the first argument. */
2039 case BUILT_IN_INDEX
:
2040 case BUILT_IN_STRCHR
:
2041 case BUILT_IN_STRRCHR
:
2044 ao_ref_init_from_ptr_and_size (&dref
,
2045 gimple_call_arg (call
, 0),
2047 return refs_may_alias_p_1 (&dref
, ref
, false);
2049 /* These read memory pointed to by the first argument with size
2050 in the third argument. */
2051 case BUILT_IN_MEMCHR
:
2054 ao_ref_init_from_ptr_and_size (&dref
,
2055 gimple_call_arg (call
, 0),
2056 gimple_call_arg (call
, 2));
2057 return refs_may_alias_p_1 (&dref
, ref
, false);
2059 /* These read memory pointed to by the first and second arguments. */
2060 case BUILT_IN_STRSTR
:
2061 case BUILT_IN_STRPBRK
:
2064 ao_ref_init_from_ptr_and_size (&dref
,
2065 gimple_call_arg (call
, 0),
2067 if (refs_may_alias_p_1 (&dref
, ref
, false))
2069 ao_ref_init_from_ptr_and_size (&dref
,
2070 gimple_call_arg (call
, 1),
2072 return refs_may_alias_p_1 (&dref
, ref
, false);
2075 /* The following builtins do not read from memory. */
2077 case BUILT_IN_MALLOC
:
2078 case BUILT_IN_POSIX_MEMALIGN
:
2079 case BUILT_IN_ALIGNED_ALLOC
:
2080 case BUILT_IN_CALLOC
:
2081 CASE_BUILT_IN_ALLOCA
:
2082 case BUILT_IN_STACK_SAVE
:
2083 case BUILT_IN_STACK_RESTORE
:
2084 case BUILT_IN_MEMSET
:
2085 case BUILT_IN_TM_MEMSET
:
2086 case BUILT_IN_MEMSET_CHK
:
2087 case BUILT_IN_FREXP
:
2088 case BUILT_IN_FREXPF
:
2089 case BUILT_IN_FREXPL
:
2090 case BUILT_IN_GAMMA_R
:
2091 case BUILT_IN_GAMMAF_R
:
2092 case BUILT_IN_GAMMAL_R
:
2093 case BUILT_IN_LGAMMA_R
:
2094 case BUILT_IN_LGAMMAF_R
:
2095 case BUILT_IN_LGAMMAL_R
:
2097 case BUILT_IN_MODFF
:
2098 case BUILT_IN_MODFL
:
2099 case BUILT_IN_REMQUO
:
2100 case BUILT_IN_REMQUOF
:
2101 case BUILT_IN_REMQUOL
:
2102 case BUILT_IN_SINCOS
:
2103 case BUILT_IN_SINCOSF
:
2104 case BUILT_IN_SINCOSL
:
2105 case BUILT_IN_ASSUME_ALIGNED
:
2106 case BUILT_IN_VA_END
:
2108 /* __sync_* builtins and some OpenMP builtins act as threading
2110 #undef DEF_SYNC_BUILTIN
2111 #define DEF_SYNC_BUILTIN(ENUM, NAME, TYPE, ATTRS) case ENUM:
2112 #include "sync-builtins.def"
2113 #undef DEF_SYNC_BUILTIN
2114 case BUILT_IN_GOMP_ATOMIC_START
:
2115 case BUILT_IN_GOMP_ATOMIC_END
:
2116 case BUILT_IN_GOMP_BARRIER
:
2117 case BUILT_IN_GOMP_BARRIER_CANCEL
:
2118 case BUILT_IN_GOMP_TASKWAIT
:
2119 case BUILT_IN_GOMP_TASKGROUP_END
:
2120 case BUILT_IN_GOMP_CRITICAL_START
:
2121 case BUILT_IN_GOMP_CRITICAL_END
:
2122 case BUILT_IN_GOMP_CRITICAL_NAME_START
:
2123 case BUILT_IN_GOMP_CRITICAL_NAME_END
:
2124 case BUILT_IN_GOMP_LOOP_END
:
2125 case BUILT_IN_GOMP_LOOP_END_CANCEL
:
2126 case BUILT_IN_GOMP_ORDERED_START
:
2127 case BUILT_IN_GOMP_ORDERED_END
:
2128 case BUILT_IN_GOMP_SECTIONS_END
:
2129 case BUILT_IN_GOMP_SECTIONS_END_CANCEL
:
2130 case BUILT_IN_GOMP_SINGLE_COPY_START
:
2131 case BUILT_IN_GOMP_SINGLE_COPY_END
:
2135 /* Fallthru to general call handling. */;
2138 /* Check if base is a global static variable that is not read
2140 if (callee
!= NULL_TREE
&& VAR_P (base
) && TREE_STATIC (base
))
2142 struct cgraph_node
*node
= cgraph_node::get (callee
);
2145 /* FIXME: Callee can be an OMP builtin that does not have a call graph
2146 node yet. We should enforce that there are nodes for all decls in the
2147 IL and remove this check instead. */
2149 && (not_read
= ipa_reference_get_not_read_global (node
))
2150 && bitmap_bit_p (not_read
, ipa_reference_var_uid (base
)))
2154 /* Check if the base variable is call-used. */
2157 if (pt_solution_includes (gimple_call_use_set (call
), base
))
2160 else if ((TREE_CODE (base
) == MEM_REF
2161 || TREE_CODE (base
) == TARGET_MEM_REF
)
2162 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
)
2164 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (TREE_OPERAND (base
, 0));
2168 if (pt_solutions_intersect (gimple_call_use_set (call
), &pi
->pt
))
2174 /* Inspect call arguments for passed-by-value aliases. */
2176 for (i
= 0; i
< gimple_call_num_args (call
); ++i
)
2178 tree op
= gimple_call_arg (call
, i
);
2179 int flags
= gimple_call_arg_flags (call
, i
);
2181 if (flags
& EAF_UNUSED
)
2184 if (TREE_CODE (op
) == WITH_SIZE_EXPR
)
2185 op
= TREE_OPERAND (op
, 0);
2187 if (TREE_CODE (op
) != SSA_NAME
2188 && !is_gimple_min_invariant (op
))
2191 ao_ref_init (&r
, op
);
2192 if (refs_may_alias_p_1 (&r
, ref
, tbaa_p
))
2201 ref_maybe_used_by_call_p (gcall
*call
, ao_ref
*ref
, bool tbaa_p
)
2204 res
= ref_maybe_used_by_call_p_1 (call
, ref
, tbaa_p
);
2206 ++alias_stats
.ref_maybe_used_by_call_p_may_alias
;
2208 ++alias_stats
.ref_maybe_used_by_call_p_no_alias
;
2213 /* If the statement STMT may use the memory reference REF return
2214 true, otherwise return false. */
2217 ref_maybe_used_by_stmt_p (gimple
*stmt
, ao_ref
*ref
, bool tbaa_p
)
2219 if (is_gimple_assign (stmt
))
2223 /* All memory assign statements are single. */
2224 if (!gimple_assign_single_p (stmt
))
2227 rhs
= gimple_assign_rhs1 (stmt
);
2228 if (is_gimple_reg (rhs
)
2229 || is_gimple_min_invariant (rhs
)
2230 || gimple_assign_rhs_code (stmt
) == CONSTRUCTOR
)
2233 return refs_may_alias_p (rhs
, ref
, tbaa_p
);
2235 else if (is_gimple_call (stmt
))
2236 return ref_maybe_used_by_call_p (as_a
<gcall
*> (stmt
), ref
, tbaa_p
);
2237 else if (greturn
*return_stmt
= dyn_cast
<greturn
*> (stmt
))
2239 tree retval
= gimple_return_retval (return_stmt
);
2241 && TREE_CODE (retval
) != SSA_NAME
2242 && !is_gimple_min_invariant (retval
)
2243 && refs_may_alias_p (retval
, ref
, tbaa_p
))
2245 /* If ref escapes the function then the return acts as a use. */
2246 tree base
= ao_ref_base (ref
);
2249 else if (DECL_P (base
))
2250 return is_global_var (base
);
2251 else if (TREE_CODE (base
) == MEM_REF
2252 || TREE_CODE (base
) == TARGET_MEM_REF
)
2253 return ptr_deref_may_alias_global_p (TREE_OPERAND (base
, 0));
2261 ref_maybe_used_by_stmt_p (gimple
*stmt
, tree ref
, bool tbaa_p
)
2264 ao_ref_init (&r
, ref
);
2265 return ref_maybe_used_by_stmt_p (stmt
, &r
, tbaa_p
);
2268 /* If the call in statement CALL may clobber the memory reference REF
2269 return true, otherwise return false. */
2272 call_may_clobber_ref_p_1 (gcall
*call
, ao_ref
*ref
)
2277 /* If the call is pure or const it cannot clobber anything. */
2278 if (gimple_call_flags (call
)
2279 & (ECF_PURE
|ECF_CONST
|ECF_LOOPING_CONST_OR_PURE
|ECF_NOVOPS
))
2281 if (gimple_call_internal_p (call
))
2282 switch (gimple_call_internal_fn (call
))
2284 /* Treat these internal calls like ECF_PURE for aliasing,
2285 they don't write to any memory the program should care about.
2286 They have important other side-effects, and read memory,
2287 so can't be ECF_NOVOPS. */
2288 case IFN_UBSAN_NULL
:
2289 case IFN_UBSAN_BOUNDS
:
2290 case IFN_UBSAN_VPTR
:
2291 case IFN_UBSAN_OBJECT_SIZE
:
2293 case IFN_ASAN_CHECK
:
2299 base
= ao_ref_base (ref
);
2303 if (TREE_CODE (base
) == SSA_NAME
2304 || CONSTANT_CLASS_P (base
))
2307 /* A call that is not without side-effects might involve volatile
2308 accesses and thus conflicts with all other volatile accesses. */
2309 if (ref
->volatile_p
)
2312 /* If the reference is based on a decl that is not aliased the call
2313 cannot possibly clobber it. */
2315 && !may_be_aliased (base
)
2316 /* But local non-readonly statics can be modified through recursion
2317 or the call may implement a threading barrier which we must
2318 treat as may-def. */
2319 && (TREE_READONLY (base
)
2320 || !is_global_var (base
)))
2323 /* If the reference is based on a pointer that points to memory
2324 that may not be written to then the call cannot possibly clobber it. */
2325 if ((TREE_CODE (base
) == MEM_REF
2326 || TREE_CODE (base
) == TARGET_MEM_REF
)
2327 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
2328 && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base
, 0)))
2331 callee
= gimple_call_fndecl (call
);
2333 /* Handle those builtin functions explicitly that do not act as
2334 escape points. See tree-ssa-structalias.c:find_func_aliases
2335 for the list of builtins we might need to handle here. */
2336 if (callee
!= NULL_TREE
2337 && gimple_call_builtin_p (call
, BUILT_IN_NORMAL
))
2338 switch (DECL_FUNCTION_CODE (callee
))
2340 /* All the following functions clobber memory pointed to by
2341 their first argument. */
2342 case BUILT_IN_STRCPY
:
2343 case BUILT_IN_STRNCPY
:
2344 case BUILT_IN_MEMCPY
:
2345 case BUILT_IN_MEMMOVE
:
2346 case BUILT_IN_MEMPCPY
:
2347 case BUILT_IN_STPCPY
:
2348 case BUILT_IN_STPNCPY
:
2349 case BUILT_IN_STRCAT
:
2350 case BUILT_IN_STRNCAT
:
2351 case BUILT_IN_MEMSET
:
2352 case BUILT_IN_TM_MEMSET
:
2353 CASE_BUILT_IN_TM_STORE (1):
2354 CASE_BUILT_IN_TM_STORE (2):
2355 CASE_BUILT_IN_TM_STORE (4):
2356 CASE_BUILT_IN_TM_STORE (8):
2357 CASE_BUILT_IN_TM_STORE (FLOAT
):
2358 CASE_BUILT_IN_TM_STORE (DOUBLE
):
2359 CASE_BUILT_IN_TM_STORE (LDOUBLE
):
2360 CASE_BUILT_IN_TM_STORE (M64
):
2361 CASE_BUILT_IN_TM_STORE (M128
):
2362 CASE_BUILT_IN_TM_STORE (M256
):
2363 case BUILT_IN_TM_MEMCPY
:
2364 case BUILT_IN_TM_MEMMOVE
:
2367 tree size
= NULL_TREE
;
2368 /* Don't pass in size for strncat, as the maximum size
2369 is strlen (dest) + n + 1 instead of n, resp.
2370 n + 1 at dest + strlen (dest), but strlen (dest) isn't
2372 if (gimple_call_num_args (call
) == 3
2373 && DECL_FUNCTION_CODE (callee
) != BUILT_IN_STRNCAT
)
2374 size
= gimple_call_arg (call
, 2);
2375 ao_ref_init_from_ptr_and_size (&dref
,
2376 gimple_call_arg (call
, 0),
2378 return refs_may_alias_p_1 (&dref
, ref
, false);
2380 case BUILT_IN_STRCPY_CHK
:
2381 case BUILT_IN_STRNCPY_CHK
:
2382 case BUILT_IN_MEMCPY_CHK
:
2383 case BUILT_IN_MEMMOVE_CHK
:
2384 case BUILT_IN_MEMPCPY_CHK
:
2385 case BUILT_IN_STPCPY_CHK
:
2386 case BUILT_IN_STPNCPY_CHK
:
2387 case BUILT_IN_STRCAT_CHK
:
2388 case BUILT_IN_STRNCAT_CHK
:
2389 case BUILT_IN_MEMSET_CHK
:
2392 tree size
= NULL_TREE
;
2393 /* Don't pass in size for __strncat_chk, as the maximum size
2394 is strlen (dest) + n + 1 instead of n, resp.
2395 n + 1 at dest + strlen (dest), but strlen (dest) isn't
2397 if (gimple_call_num_args (call
) == 4
2398 && DECL_FUNCTION_CODE (callee
) != BUILT_IN_STRNCAT_CHK
)
2399 size
= gimple_call_arg (call
, 2);
2400 ao_ref_init_from_ptr_and_size (&dref
,
2401 gimple_call_arg (call
, 0),
2403 return refs_may_alias_p_1 (&dref
, ref
, false);
2405 case BUILT_IN_BCOPY
:
2408 tree size
= gimple_call_arg (call
, 2);
2409 ao_ref_init_from_ptr_and_size (&dref
,
2410 gimple_call_arg (call
, 1),
2412 return refs_may_alias_p_1 (&dref
, ref
, false);
2414 /* Allocating memory does not have any side-effects apart from
2415 being the definition point for the pointer. */
2416 case BUILT_IN_MALLOC
:
2417 case BUILT_IN_ALIGNED_ALLOC
:
2418 case BUILT_IN_CALLOC
:
2419 case BUILT_IN_STRDUP
:
2420 case BUILT_IN_STRNDUP
:
2421 /* Unix98 specifies that errno is set on allocation failure. */
2423 && targetm
.ref_may_alias_errno (ref
))
2426 case BUILT_IN_STACK_SAVE
:
2427 CASE_BUILT_IN_ALLOCA
:
2428 case BUILT_IN_ASSUME_ALIGNED
:
2430 /* But posix_memalign stores a pointer into the memory pointed to
2431 by its first argument. */
2432 case BUILT_IN_POSIX_MEMALIGN
:
2434 tree ptrptr
= gimple_call_arg (call
, 0);
2436 ao_ref_init_from_ptr_and_size (&dref
, ptrptr
,
2437 TYPE_SIZE_UNIT (ptr_type_node
));
2438 return (refs_may_alias_p_1 (&dref
, ref
, false)
2440 && targetm
.ref_may_alias_errno (ref
)));
2442 /* Freeing memory kills the pointed-to memory. More importantly
2443 the call has to serve as a barrier for moving loads and stores
2446 case BUILT_IN_VA_END
:
2448 tree ptr
= gimple_call_arg (call
, 0);
2449 return ptr_deref_may_alias_ref_p_1 (ptr
, ref
);
2451 /* Realloc serves both as allocation point and deallocation point. */
2452 case BUILT_IN_REALLOC
:
2454 tree ptr
= gimple_call_arg (call
, 0);
2455 /* Unix98 specifies that errno is set on allocation failure. */
2456 return ((flag_errno_math
2457 && targetm
.ref_may_alias_errno (ref
))
2458 || ptr_deref_may_alias_ref_p_1 (ptr
, ref
));
2460 case BUILT_IN_GAMMA_R
:
2461 case BUILT_IN_GAMMAF_R
:
2462 case BUILT_IN_GAMMAL_R
:
2463 case BUILT_IN_LGAMMA_R
:
2464 case BUILT_IN_LGAMMAF_R
:
2465 case BUILT_IN_LGAMMAL_R
:
2467 tree out
= gimple_call_arg (call
, 1);
2468 if (ptr_deref_may_alias_ref_p_1 (out
, ref
))
2470 if (flag_errno_math
)
2474 case BUILT_IN_FREXP
:
2475 case BUILT_IN_FREXPF
:
2476 case BUILT_IN_FREXPL
:
2478 case BUILT_IN_MODFF
:
2479 case BUILT_IN_MODFL
:
2481 tree out
= gimple_call_arg (call
, 1);
2482 return ptr_deref_may_alias_ref_p_1 (out
, ref
);
2484 case BUILT_IN_REMQUO
:
2485 case BUILT_IN_REMQUOF
:
2486 case BUILT_IN_REMQUOL
:
2488 tree out
= gimple_call_arg (call
, 2);
2489 if (ptr_deref_may_alias_ref_p_1 (out
, ref
))
2491 if (flag_errno_math
)
2495 case BUILT_IN_SINCOS
:
2496 case BUILT_IN_SINCOSF
:
2497 case BUILT_IN_SINCOSL
:
2499 tree sin
= gimple_call_arg (call
, 1);
2500 tree cos
= gimple_call_arg (call
, 2);
2501 return (ptr_deref_may_alias_ref_p_1 (sin
, ref
)
2502 || ptr_deref_may_alias_ref_p_1 (cos
, ref
));
2504 /* __sync_* builtins and some OpenMP builtins act as threading
2506 #undef DEF_SYNC_BUILTIN
2507 #define DEF_SYNC_BUILTIN(ENUM, NAME, TYPE, ATTRS) case ENUM:
2508 #include "sync-builtins.def"
2509 #undef DEF_SYNC_BUILTIN
2510 case BUILT_IN_GOMP_ATOMIC_START
:
2511 case BUILT_IN_GOMP_ATOMIC_END
:
2512 case BUILT_IN_GOMP_BARRIER
:
2513 case BUILT_IN_GOMP_BARRIER_CANCEL
:
2514 case BUILT_IN_GOMP_TASKWAIT
:
2515 case BUILT_IN_GOMP_TASKGROUP_END
:
2516 case BUILT_IN_GOMP_CRITICAL_START
:
2517 case BUILT_IN_GOMP_CRITICAL_END
:
2518 case BUILT_IN_GOMP_CRITICAL_NAME_START
:
2519 case BUILT_IN_GOMP_CRITICAL_NAME_END
:
2520 case BUILT_IN_GOMP_LOOP_END
:
2521 case BUILT_IN_GOMP_LOOP_END_CANCEL
:
2522 case BUILT_IN_GOMP_ORDERED_START
:
2523 case BUILT_IN_GOMP_ORDERED_END
:
2524 case BUILT_IN_GOMP_SECTIONS_END
:
2525 case BUILT_IN_GOMP_SECTIONS_END_CANCEL
:
2526 case BUILT_IN_GOMP_SINGLE_COPY_START
:
2527 case BUILT_IN_GOMP_SINGLE_COPY_END
:
2530 /* Fallthru to general call handling. */;
2533 /* Check if base is a global static variable that is not written
2535 if (callee
!= NULL_TREE
&& VAR_P (base
) && TREE_STATIC (base
))
2537 struct cgraph_node
*node
= cgraph_node::get (callee
);
2541 && (not_written
= ipa_reference_get_not_written_global (node
))
2542 && bitmap_bit_p (not_written
, ipa_reference_var_uid (base
)))
2546 /* Check if the base variable is call-clobbered. */
2548 return pt_solution_includes (gimple_call_clobber_set (call
), base
);
2549 else if ((TREE_CODE (base
) == MEM_REF
2550 || TREE_CODE (base
) == TARGET_MEM_REF
)
2551 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
)
2553 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (TREE_OPERAND (base
, 0));
2557 return pt_solutions_intersect (gimple_call_clobber_set (call
), &pi
->pt
);
2563 /* If the call in statement CALL may clobber the memory reference REF
2564 return true, otherwise return false. */
2567 call_may_clobber_ref_p (gcall
*call
, tree ref
)
2571 ao_ref_init (&r
, ref
);
2572 res
= call_may_clobber_ref_p_1 (call
, &r
);
2574 ++alias_stats
.call_may_clobber_ref_p_may_alias
;
2576 ++alias_stats
.call_may_clobber_ref_p_no_alias
;
2581 /* If the statement STMT may clobber the memory reference REF return true,
2582 otherwise return false. */
2585 stmt_may_clobber_ref_p_1 (gimple
*stmt
, ao_ref
*ref
, bool tbaa_p
)
2587 if (is_gimple_call (stmt
))
2589 tree lhs
= gimple_call_lhs (stmt
);
2591 && TREE_CODE (lhs
) != SSA_NAME
)
2594 ao_ref_init (&r
, lhs
);
2595 if (refs_may_alias_p_1 (ref
, &r
, tbaa_p
))
2599 return call_may_clobber_ref_p_1 (as_a
<gcall
*> (stmt
), ref
);
2601 else if (gimple_assign_single_p (stmt
))
2603 tree lhs
= gimple_assign_lhs (stmt
);
2604 if (TREE_CODE (lhs
) != SSA_NAME
)
2607 ao_ref_init (&r
, lhs
);
2608 return refs_may_alias_p_1 (ref
, &r
, tbaa_p
);
2611 else if (gimple_code (stmt
) == GIMPLE_ASM
)
2618 stmt_may_clobber_ref_p (gimple
*stmt
, tree ref
, bool tbaa_p
)
2621 ao_ref_init (&r
, ref
);
2622 return stmt_may_clobber_ref_p_1 (stmt
, &r
, tbaa_p
);
2625 /* Return true if store1 and store2 described by corresponding tuples
2626 <BASE, OFFSET, SIZE, MAX_SIZE> have the same size and store to the same
2630 same_addr_size_stores_p (tree base1
, poly_int64 offset1
, poly_int64 size1
,
2631 poly_int64 max_size1
,
2632 tree base2
, poly_int64 offset2
, poly_int64 size2
,
2633 poly_int64 max_size2
)
2635 /* Offsets need to be 0. */
2636 if (maybe_ne (offset1
, 0)
2637 || maybe_ne (offset2
, 0))
2640 bool base1_obj_p
= SSA_VAR_P (base1
);
2641 bool base2_obj_p
= SSA_VAR_P (base2
);
2643 /* We need one object. */
2644 if (base1_obj_p
== base2_obj_p
)
2646 tree obj
= base1_obj_p
? base1
: base2
;
2648 /* And we need one MEM_REF. */
2649 bool base1_memref_p
= TREE_CODE (base1
) == MEM_REF
;
2650 bool base2_memref_p
= TREE_CODE (base2
) == MEM_REF
;
2651 if (base1_memref_p
== base2_memref_p
)
2653 tree memref
= base1_memref_p
? base1
: base2
;
2655 /* Sizes need to be valid. */
2656 if (!known_size_p (max_size1
)
2657 || !known_size_p (max_size2
)
2658 || !known_size_p (size1
)
2659 || !known_size_p (size2
))
2662 /* Max_size needs to match size. */
2663 if (maybe_ne (max_size1
, size1
)
2664 || maybe_ne (max_size2
, size2
))
2667 /* Sizes need to match. */
2668 if (maybe_ne (size1
, size2
))
2672 /* Check that memref is a store to pointer with singleton points-to info. */
2673 if (!integer_zerop (TREE_OPERAND (memref
, 1)))
2675 tree ptr
= TREE_OPERAND (memref
, 0);
2676 if (TREE_CODE (ptr
) != SSA_NAME
)
2678 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (ptr
);
2679 unsigned int pt_uid
;
2681 || !pt_solution_singleton_or_null_p (&pi
->pt
, &pt_uid
))
2684 /* Be conservative with non-call exceptions when the address might
2686 if (cfun
->can_throw_non_call_exceptions
&& pi
->pt
.null
)
2689 /* Check that ptr points relative to obj. */
2690 unsigned int obj_uid
= DECL_PT_UID (obj
);
2691 if (obj_uid
!= pt_uid
)
2694 /* Check that the object size is the same as the store size. That ensures us
2695 that ptr points to the start of obj. */
2696 return (DECL_SIZE (obj
)
2697 && poly_int_tree_p (DECL_SIZE (obj
))
2698 && known_eq (wi::to_poly_offset (DECL_SIZE (obj
)), size1
));
2701 /* If STMT kills the memory reference REF return true, otherwise
2705 stmt_kills_ref_p (gimple
*stmt
, ao_ref
*ref
)
2707 if (!ao_ref_base (ref
))
2710 if (gimple_has_lhs (stmt
)
2711 && TREE_CODE (gimple_get_lhs (stmt
)) != SSA_NAME
2712 /* The assignment is not necessarily carried out if it can throw
2713 and we can catch it in the current function where we could inspect
2715 ??? We only need to care about the RHS throwing. For aggregate
2716 assignments or similar calls and non-call exceptions the LHS
2717 might throw as well. */
2718 && !stmt_can_throw_internal (cfun
, stmt
))
2720 tree lhs
= gimple_get_lhs (stmt
);
2721 /* If LHS is literally a base of the access we are done. */
2724 tree base
= ref
->ref
;
2725 tree innermost_dropped_array_ref
= NULL_TREE
;
2726 if (handled_component_p (base
))
2728 tree saved_lhs0
= NULL_TREE
;
2729 if (handled_component_p (lhs
))
2731 saved_lhs0
= TREE_OPERAND (lhs
, 0);
2732 TREE_OPERAND (lhs
, 0) = integer_zero_node
;
2736 /* Just compare the outermost handled component, if
2737 they are equal we have found a possible common
2739 tree saved_base0
= TREE_OPERAND (base
, 0);
2740 TREE_OPERAND (base
, 0) = integer_zero_node
;
2741 bool res
= operand_equal_p (lhs
, base
, 0);
2742 TREE_OPERAND (base
, 0) = saved_base0
;
2745 /* Remember if we drop an array-ref that we need to
2746 double-check not being at struct end. */
2747 if (TREE_CODE (base
) == ARRAY_REF
2748 || TREE_CODE (base
) == ARRAY_RANGE_REF
)
2749 innermost_dropped_array_ref
= base
;
2750 /* Otherwise drop handled components of the access. */
2753 while (handled_component_p (base
));
2755 TREE_OPERAND (lhs
, 0) = saved_lhs0
;
2757 /* Finally check if the lhs has the same address and size as the
2758 base candidate of the access. Watch out if we have dropped
2759 an array-ref that was at struct end, this means ref->ref may
2760 be outside of the TYPE_SIZE of its base. */
2761 if ((! innermost_dropped_array_ref
2762 || ! array_at_struct_end_p (innermost_dropped_array_ref
))
2764 || (((TYPE_SIZE (TREE_TYPE (lhs
))
2765 == TYPE_SIZE (TREE_TYPE (base
)))
2766 || (TYPE_SIZE (TREE_TYPE (lhs
))
2767 && TYPE_SIZE (TREE_TYPE (base
))
2768 && operand_equal_p (TYPE_SIZE (TREE_TYPE (lhs
)),
2769 TYPE_SIZE (TREE_TYPE (base
)),
2771 && operand_equal_p (lhs
, base
,
2773 | OEP_MATCH_SIDE_EFFECTS
))))
2777 /* Now look for non-literal equal bases with the restriction of
2778 handling constant offset and size. */
2779 /* For a must-alias check we need to be able to constrain
2780 the access properly. */
2781 if (!ref
->max_size_known_p ())
2783 poly_int64 size
, offset
, max_size
, ref_offset
= ref
->offset
;
2785 tree base
= get_ref_base_and_extent (lhs
, &offset
, &size
, &max_size
,
2787 /* We can get MEM[symbol: sZ, index: D.8862_1] here,
2788 so base == ref->base does not always hold. */
2789 if (base
!= ref
->base
)
2791 /* Try using points-to info. */
2792 if (same_addr_size_stores_p (base
, offset
, size
, max_size
, ref
->base
,
2793 ref
->offset
, ref
->size
, ref
->max_size
))
2796 /* If both base and ref->base are MEM_REFs, only compare the
2797 first operand, and if the second operand isn't equal constant,
2798 try to add the offsets into offset and ref_offset. */
2799 if (TREE_CODE (base
) == MEM_REF
&& TREE_CODE (ref
->base
) == MEM_REF
2800 && TREE_OPERAND (base
, 0) == TREE_OPERAND (ref
->base
, 0))
2802 if (!tree_int_cst_equal (TREE_OPERAND (base
, 1),
2803 TREE_OPERAND (ref
->base
, 1)))
2805 poly_offset_int off1
= mem_ref_offset (base
);
2806 off1
<<= LOG2_BITS_PER_UNIT
;
2808 poly_offset_int off2
= mem_ref_offset (ref
->base
);
2809 off2
<<= LOG2_BITS_PER_UNIT
;
2811 if (!off1
.to_shwi (&offset
) || !off2
.to_shwi (&ref_offset
))
2818 /* For a must-alias check we need to be able to constrain
2819 the access properly. */
2820 if (known_eq (size
, max_size
)
2821 && known_subrange_p (ref_offset
, ref
->max_size
, offset
, size
))
2825 if (is_gimple_call (stmt
))
2827 tree callee
= gimple_call_fndecl (stmt
);
2828 if (callee
!= NULL_TREE
2829 && gimple_call_builtin_p (stmt
, BUILT_IN_NORMAL
))
2830 switch (DECL_FUNCTION_CODE (callee
))
2834 tree ptr
= gimple_call_arg (stmt
, 0);
2835 tree base
= ao_ref_base (ref
);
2836 if (base
&& TREE_CODE (base
) == MEM_REF
2837 && TREE_OPERAND (base
, 0) == ptr
)
2842 case BUILT_IN_MEMCPY
:
2843 case BUILT_IN_MEMPCPY
:
2844 case BUILT_IN_MEMMOVE
:
2845 case BUILT_IN_MEMSET
:
2846 case BUILT_IN_MEMCPY_CHK
:
2847 case BUILT_IN_MEMPCPY_CHK
:
2848 case BUILT_IN_MEMMOVE_CHK
:
2849 case BUILT_IN_MEMSET_CHK
:
2850 case BUILT_IN_STRNCPY
:
2851 case BUILT_IN_STPNCPY
:
2852 case BUILT_IN_CALLOC
:
2854 /* For a must-alias check we need to be able to constrain
2855 the access properly. */
2856 if (!ref
->max_size_known_p ())
2861 /* In execution order a calloc call will never kill
2862 anything. However, DSE will (ab)use this interface
2863 to ask if a calloc call writes the same memory locations
2864 as a later assignment, memset, etc. So handle calloc
2865 in the expected way. */
2866 if (DECL_FUNCTION_CODE (callee
) == BUILT_IN_CALLOC
)
2868 tree arg0
= gimple_call_arg (stmt
, 0);
2869 tree arg1
= gimple_call_arg (stmt
, 1);
2870 if (TREE_CODE (arg0
) != INTEGER_CST
2871 || TREE_CODE (arg1
) != INTEGER_CST
)
2874 dest
= gimple_call_lhs (stmt
);
2875 len
= fold_build2 (MULT_EXPR
, TREE_TYPE (arg0
), arg0
, arg1
);
2879 dest
= gimple_call_arg (stmt
, 0);
2880 len
= gimple_call_arg (stmt
, 2);
2882 if (!poly_int_tree_p (len
))
2884 tree rbase
= ref
->base
;
2885 poly_offset_int roffset
= ref
->offset
;
2887 ao_ref_init_from_ptr_and_size (&dref
, dest
, len
);
2888 tree base
= ao_ref_base (&dref
);
2889 poly_offset_int offset
= dref
.offset
;
2890 if (!base
|| !known_size_p (dref
.size
))
2892 if (TREE_CODE (base
) == MEM_REF
)
2894 if (TREE_CODE (rbase
) != MEM_REF
)
2896 // Compare pointers.
2897 offset
+= mem_ref_offset (base
) << LOG2_BITS_PER_UNIT
;
2898 roffset
+= mem_ref_offset (rbase
) << LOG2_BITS_PER_UNIT
;
2899 base
= TREE_OPERAND (base
, 0);
2900 rbase
= TREE_OPERAND (rbase
, 0);
2903 && known_subrange_p (roffset
, ref
->max_size
, offset
,
2904 wi::to_poly_offset (len
)
2905 << LOG2_BITS_PER_UNIT
))
2910 case BUILT_IN_VA_END
:
2912 tree ptr
= gimple_call_arg (stmt
, 0);
2913 if (TREE_CODE (ptr
) == ADDR_EXPR
)
2915 tree base
= ao_ref_base (ref
);
2916 if (TREE_OPERAND (ptr
, 0) == base
)
2929 stmt_kills_ref_p (gimple
*stmt
, tree ref
)
2932 ao_ref_init (&r
, ref
);
2933 return stmt_kills_ref_p (stmt
, &r
);
2937 /* Walk the virtual use-def chain of VUSE until hitting the virtual operand
2938 TARGET or a statement clobbering the memory reference REF in which
2939 case false is returned. The walk starts with VUSE, one argument of PHI. */
2942 maybe_skip_until (gimple
*phi
, tree
&target
, basic_block target_bb
,
2943 ao_ref
*ref
, tree vuse
, unsigned int &limit
, bitmap
*visited
,
2944 bool abort_on_visited
,
2945 void *(*translate
)(ao_ref
*, tree
, void *, bool *),
2948 basic_block bb
= gimple_bb (phi
);
2951 *visited
= BITMAP_ALLOC (NULL
);
2953 bitmap_set_bit (*visited
, SSA_NAME_VERSION (PHI_RESULT (phi
)));
2955 /* Walk until we hit the target. */
2956 while (vuse
!= target
)
2958 gimple
*def_stmt
= SSA_NAME_DEF_STMT (vuse
);
2959 /* If we are searching for the target VUSE by walking up to
2960 TARGET_BB dominating the original PHI we are finished once
2961 we reach a default def or a definition in a block dominating
2962 that block. Update TARGET and return. */
2964 && (gimple_nop_p (def_stmt
)
2965 || dominated_by_p (CDI_DOMINATORS
,
2966 target_bb
, gimple_bb (def_stmt
))))
2972 /* Recurse for PHI nodes. */
2973 if (gimple_code (def_stmt
) == GIMPLE_PHI
)
2975 /* An already visited PHI node ends the walk successfully. */
2976 if (bitmap_bit_p (*visited
, SSA_NAME_VERSION (PHI_RESULT (def_stmt
))))
2977 return !abort_on_visited
;
2978 vuse
= get_continuation_for_phi (def_stmt
, ref
, limit
,
2979 visited
, abort_on_visited
,
2985 else if (gimple_nop_p (def_stmt
))
2989 /* A clobbering statement or the end of the IL ends it failing. */
2990 if ((int)limit
<= 0)
2993 if (stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
2995 bool disambiguate_only
= true;
2997 && (*translate
) (ref
, vuse
, data
, &disambiguate_only
) == NULL
)
3003 /* If we reach a new basic-block see if we already skipped it
3004 in a previous walk that ended successfully. */
3005 if (gimple_bb (def_stmt
) != bb
)
3007 if (!bitmap_set_bit (*visited
, SSA_NAME_VERSION (vuse
)))
3008 return !abort_on_visited
;
3009 bb
= gimple_bb (def_stmt
);
3011 vuse
= gimple_vuse (def_stmt
);
3017 /* Starting from a PHI node for the virtual operand of the memory reference
3018 REF find a continuation virtual operand that allows to continue walking
3019 statements dominating PHI skipping only statements that cannot possibly
3020 clobber REF. Decrements LIMIT for each alias disambiguation done
3021 and aborts the walk, returning NULL_TREE if it reaches zero.
3022 Returns NULL_TREE if no suitable virtual operand can be found. */
3025 get_continuation_for_phi (gimple
*phi
, ao_ref
*ref
,
3026 unsigned int &limit
, bitmap
*visited
,
3027 bool abort_on_visited
,
3028 void *(*translate
)(ao_ref
*, tree
, void *, bool *),
3031 unsigned nargs
= gimple_phi_num_args (phi
);
3033 /* Through a single-argument PHI we can simply look through. */
3035 return PHI_ARG_DEF (phi
, 0);
3037 /* For two or more arguments try to pairwise skip non-aliasing code
3038 until we hit the phi argument definition that dominates the other one. */
3039 basic_block phi_bb
= gimple_bb (phi
);
3043 /* Find a candidate for the virtual operand which definition
3044 dominates those of all others. */
3045 /* First look if any of the args themselves satisfy this. */
3046 for (i
= 0; i
< nargs
; ++i
)
3048 arg0
= PHI_ARG_DEF (phi
, i
);
3049 if (SSA_NAME_IS_DEFAULT_DEF (arg0
))
3051 basic_block def_bb
= gimple_bb (SSA_NAME_DEF_STMT (arg0
));
3052 if (def_bb
!= phi_bb
3053 && dominated_by_p (CDI_DOMINATORS
, phi_bb
, def_bb
))
3057 /* If not, look if we can reach such candidate by walking defs
3058 until we hit the immediate dominator. maybe_skip_until will
3060 basic_block dom
= get_immediate_dominator (CDI_DOMINATORS
, phi_bb
);
3062 /* Then check against the (to be) found candidate. */
3063 for (i
= 0; i
< nargs
; ++i
)
3065 arg1
= PHI_ARG_DEF (phi
, i
);
3068 else if (! maybe_skip_until (phi
, arg0
, dom
, ref
, arg1
, limit
, visited
,
3070 /* Do not translate when walking over
3074 gimple_bb (SSA_NAME_DEF_STMT (arg1
)),
3076 ? NULL
: translate
, data
))
3083 /* Based on the memory reference REF and its virtual use VUSE call
3084 WALKER for each virtual use that is equivalent to VUSE, including VUSE
3085 itself. That is, for each virtual use for which its defining statement
3086 does not clobber REF.
3088 WALKER is called with REF, the current virtual use and DATA. If
3089 WALKER returns non-NULL the walk stops and its result is returned.
3090 At the end of a non-successful walk NULL is returned.
3092 TRANSLATE if non-NULL is called with a pointer to REF, the virtual
3093 use which definition is a statement that may clobber REF and DATA.
3094 If TRANSLATE returns (void *)-1 the walk stops and NULL is returned.
3095 If TRANSLATE returns non-NULL the walk stops and its result is returned.
3096 If TRANSLATE returns NULL the walk continues and TRANSLATE is supposed
3097 to adjust REF and *DATA to make that valid.
3099 VALUEIZE if non-NULL is called with the next VUSE that is considered
3100 and return value is substituted for that. This can be used to
3101 implement optimistic value-numbering for example. Note that the
3102 VUSE argument is assumed to be valueized already.
3104 LIMIT specifies the number of alias queries we are allowed to do,
3105 the walk stops when it reaches zero and NULL is returned. LIMIT
3106 is decremented by the number of alias queries (plus adjustments
3107 done by the callbacks) upon return.
3109 TODO: Cache the vector of equivalent vuses per ref, vuse pair. */
3112 walk_non_aliased_vuses (ao_ref
*ref
, tree vuse
,
3113 void *(*walker
)(ao_ref
*, tree
, void *),
3114 void *(*translate
)(ao_ref
*, tree
, void *, bool *),
3115 tree (*valueize
)(tree
),
3116 unsigned &limit
, void *data
)
3118 bitmap visited
= NULL
;
3120 bool translated
= false;
3122 timevar_push (TV_ALIAS_STMT_WALK
);
3128 /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */
3129 res
= (*walker
) (ref
, vuse
, data
);
3131 if (res
== (void *)-1)
3136 /* Lookup succeeded. */
3137 else if (res
!= NULL
)
3142 vuse
= valueize (vuse
);
3149 def_stmt
= SSA_NAME_DEF_STMT (vuse
);
3150 if (gimple_nop_p (def_stmt
))
3152 else if (gimple_code (def_stmt
) == GIMPLE_PHI
)
3153 vuse
= get_continuation_for_phi (def_stmt
, ref
, limit
,
3154 &visited
, translated
, translate
, data
);
3157 if ((int)limit
<= 0)
3163 if (stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
3167 bool disambiguate_only
= false;
3168 res
= (*translate
) (ref
, vuse
, data
, &disambiguate_only
);
3169 /* Failed lookup and translation. */
3170 if (res
== (void *)-1)
3175 /* Lookup succeeded. */
3176 else if (res
!= NULL
)
3178 /* Translation succeeded, continue walking. */
3179 translated
= translated
|| !disambiguate_only
;
3181 vuse
= gimple_vuse (def_stmt
);
3187 BITMAP_FREE (visited
);
3189 timevar_pop (TV_ALIAS_STMT_WALK
);
3195 /* Based on the memory reference REF call WALKER for each vdef which
3196 defining statement may clobber REF, starting with VDEF. If REF
3197 is NULL_TREE, each defining statement is visited.
3199 WALKER is called with REF, the current vdef and DATA. If WALKER
3200 returns true the walk is stopped, otherwise it continues.
3202 If function entry is reached, FUNCTION_ENTRY_REACHED is set to true.
3203 The pointer may be NULL and then we do not track this information.
3205 At PHI nodes walk_aliased_vdefs forks into one walk for reach
3206 PHI argument (but only one walk continues on merge points), the
3207 return value is true if any of the walks was successful.
3209 The function returns the number of statements walked or -1 if
3210 LIMIT stmts were walked and the walk was aborted at this point.
3211 If LIMIT is zero the walk is not aborted. */
3214 walk_aliased_vdefs_1 (ao_ref
*ref
, tree vdef
,
3215 bool (*walker
)(ao_ref
*, tree
, void *), void *data
,
3216 bitmap
*visited
, unsigned int cnt
,
3217 bool *function_entry_reached
, unsigned limit
)
3221 gimple
*def_stmt
= SSA_NAME_DEF_STMT (vdef
);
3224 && !bitmap_set_bit (*visited
, SSA_NAME_VERSION (vdef
)))
3227 if (gimple_nop_p (def_stmt
))
3229 if (function_entry_reached
)
3230 *function_entry_reached
= true;
3233 else if (gimple_code (def_stmt
) == GIMPLE_PHI
)
3237 *visited
= BITMAP_ALLOC (NULL
);
3238 for (i
= 0; i
< gimple_phi_num_args (def_stmt
); ++i
)
3240 int res
= walk_aliased_vdefs_1 (ref
,
3241 gimple_phi_arg_def (def_stmt
, i
),
3242 walker
, data
, visited
, cnt
,
3243 function_entry_reached
, limit
);
3251 /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */
3256 || stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
3257 && (*walker
) (ref
, vdef
, data
))
3260 vdef
= gimple_vuse (def_stmt
);
3266 walk_aliased_vdefs (ao_ref
*ref
, tree vdef
,
3267 bool (*walker
)(ao_ref
*, tree
, void *), void *data
,
3269 bool *function_entry_reached
, unsigned int limit
)
3271 bitmap local_visited
= NULL
;
3274 timevar_push (TV_ALIAS_STMT_WALK
);
3276 if (function_entry_reached
)
3277 *function_entry_reached
= false;
3279 ret
= walk_aliased_vdefs_1 (ref
, vdef
, walker
, data
,
3280 visited
? visited
: &local_visited
, 0,
3281 function_entry_reached
, limit
);
3283 BITMAP_FREE (local_visited
);
3285 timevar_pop (TV_ALIAS_STMT_WALK
);