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. REF2 is the only one that can
854 be a decl in which case REF2_IS_DECL is true.
855 REF1_ALIAS_SET, BASE1_ALIAS_SET, REF2_ALIAS_SET and BASE2_ALIAS_SET
856 are the respective alias sets. */
859 aliasing_component_refs_p (tree ref1
,
860 alias_set_type ref1_alias_set
,
861 alias_set_type base1_alias_set
,
862 poly_int64 offset1
, poly_int64 max_size1
,
864 alias_set_type ref2_alias_set
,
865 alias_set_type base2_alias_set
,
866 poly_int64 offset2
, poly_int64 max_size2
,
869 /* If one reference is a component references through pointers try to find a
870 common base and apply offset based disambiguation. This handles
872 struct A { int i; int j; } *q;
873 struct B { struct A a; int k; } *p;
874 disambiguating q->i and p->a.j. */
878 int same_p1
= 0, same_p2
= 0;
879 bool maybe_match
= false;
880 tree end_struct_ref1
= NULL
, end_struct_ref2
= NULL
;
882 /* Choose bases and base types to search for. */
884 while (handled_component_p (base1
))
886 /* Generally access paths are monotous in the size of object. The
887 exception are trailing arrays of structures. I.e.
888 struct a {int array[0];};
890 struct a {int array1[0]; int array[];};
891 Such struct has size 0 but accesses to a.array may have non-zero size.
892 In this case the size of TREE_TYPE (base1) is smaller than
893 size of TREE_TYPE (TREE_OPERNAD (base1, 0)).
895 Because we compare sizes of arrays just by sizes of their elements,
896 we only need to care about zero sized array fields here. */
897 if (TREE_CODE (base1
) == COMPONENT_REF
898 && TREE_CODE (TREE_TYPE (TREE_OPERAND (base1
, 1))) == ARRAY_TYPE
899 && (!TYPE_SIZE (TREE_TYPE (TREE_OPERAND (base1
, 1)))
900 || integer_zerop (TYPE_SIZE (TREE_TYPE (TREE_OPERAND (base1
, 1)))))
901 && array_at_struct_end_p (base1
))
903 gcc_checking_assert (!end_struct_ref1
);
904 end_struct_ref1
= base1
;
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 base2
= TREE_OPERAND (base2
, 0);
923 type2
= TREE_TYPE (base2
);
925 /* Now search for the type1 in the access path of ref2. This
926 would be a common base for doing offset based disambiguation on.
927 This however only makes sense if type2 is big enough to hold type1. */
928 int cmp_outer
= compare_type_sizes (type2
, type1
);
930 /* If type2 is big enough to contain type1 walk its access path.
931 We also need to care of arrays at the end of structs that may extend
932 beyond the end of structure. */
935 && compare_type_sizes (TREE_TYPE (end_struct_ref2
), type1
) >= 0))
940 /* We walk from inner type to the outer types. If type we see is
941 already too large to be part of type1, terminate the search. */
942 int cmp
= compare_type_sizes (type1
, TREE_TYPE (*refp
));
946 || compare_type_sizes (TREE_TYPE (end_struct_ref1
),
947 TREE_TYPE (*refp
)) < 0))
949 /* If types may be of same size, see if we can decide about their
953 same_p2
= same_type_for_tbaa (TREE_TYPE (*refp
), type1
);
956 /* In case we can't decide whether types are same try to
957 continue looking for the exact match.
958 Remember however that we possibly saw a match
959 to bypass the access path continuations tests we do later. */
963 if (!handled_component_p (*refp
))
965 refp
= &TREE_OPERAND (*refp
, 0);
969 poly_int64 offadj
, sztmp
, msztmp
;
972 /* We assume that arrays can overlap by multiple of their elements
973 size as tested in gcc.dg/torture/alias-2.c.
974 This partial overlap happen only when both arrays are bases of
975 the access and not contained within another component ref.
976 To be safe we also assume partial overlap for VLAs. */
977 if (TREE_CODE (TREE_TYPE (base1
)) == ARRAY_TYPE
978 && (!TYPE_SIZE (TREE_TYPE (base1
))
979 || TREE_CODE (TYPE_SIZE (TREE_TYPE (base1
))) != INTEGER_CST
980 || (*refp
== base2
&& !ref2_is_decl
)))
982 ++alias_stats
.aliasing_component_refs_p_may_alias
;
986 get_ref_base_and_extent (*refp
, &offadj
, &sztmp
, &msztmp
, &reverse
);
988 get_ref_base_and_extent (base1
, &offadj
, &sztmp
, &msztmp
, &reverse
);
990 if (ranges_maybe_overlap_p (offset1
, max_size1
, offset2
, max_size2
))
992 ++alias_stats
.aliasing_component_refs_p_may_alias
;
997 ++alias_stats
.aliasing_component_refs_p_no_alias
;
1003 /* If we didn't find a common base, try the other way around. */
1006 && compare_type_sizes (TREE_TYPE (end_struct_ref1
), type1
) <= 0))
1011 int cmp
= compare_type_sizes (type2
, TREE_TYPE (*refp
));
1013 && (!end_struct_ref2
1014 || compare_type_sizes (TREE_TYPE (end_struct_ref2
),
1015 TREE_TYPE (*refp
)) < 0))
1017 /* If types may be of same size, see if we can decide about their
1021 same_p1
= same_type_for_tbaa (TREE_TYPE (*refp
), type2
);
1027 if (!handled_component_p (*refp
))
1029 refp
= &TREE_OPERAND (*refp
, 0);
1033 poly_int64 offadj
, sztmp
, msztmp
;
1036 if (TREE_CODE (TREE_TYPE (base2
)) == ARRAY_TYPE
1037 && (!TYPE_SIZE (TREE_TYPE (base2
))
1038 || TREE_CODE (TYPE_SIZE (TREE_TYPE (base2
))) != INTEGER_CST
1039 || (*refp
== base1
&& !ref2_is_decl
)))
1041 ++alias_stats
.aliasing_component_refs_p_may_alias
;
1045 get_ref_base_and_extent (*refp
, &offadj
, &sztmp
, &msztmp
, &reverse
);
1047 get_ref_base_and_extent (base2
, &offadj
, &sztmp
, &msztmp
, &reverse
);
1049 if (ranges_maybe_overlap_p (offset1
, max_size1
, offset2
, max_size2
))
1051 ++alias_stats
.aliasing_component_refs_p_may_alias
;
1056 ++alias_stats
.aliasing_component_refs_p_no_alias
;
1062 /* In the following code we make an assumption that the types in access
1063 paths do not overlap and thus accesses alias only if one path can be
1064 continuation of another. If we was not able to decide about equivalence,
1065 we need to give up. */
1069 /* If we have two type access paths B1.path1 and B2.path2 they may
1070 only alias if either B1 is in B2.path2 or B2 is in B1.path1.
1071 But we can still have a path that goes B1.path1...B2.path2 with
1072 a part that we do not see. So we can only disambiguate now
1073 if there is no B2 in the tail of path1 and no B1 on the
1075 if (compare_type_sizes (TREE_TYPE (ref2
), type1
) >= 0
1076 && (!end_struct_ref1
1077 || compare_type_sizes (TREE_TYPE (ref2
),
1078 TREE_TYPE (end_struct_ref1
)) >= 0)
1079 && type_has_components_p (TREE_TYPE (ref2
))
1080 && (base1_alias_set
== ref2_alias_set
1081 || alias_set_subset_of (base1_alias_set
, ref2_alias_set
)))
1083 ++alias_stats
.aliasing_component_refs_p_may_alias
;
1086 /* If this is ptr vs. decl then we know there is no ptr ... decl path. */
1088 && compare_type_sizes (TREE_TYPE (ref1
), type2
) >= 0
1089 && (!end_struct_ref2
1090 || compare_type_sizes (TREE_TYPE (ref1
),
1091 TREE_TYPE (end_struct_ref2
)) >= 0)
1092 && type_has_components_p (TREE_TYPE (ref1
))
1093 && (base2_alias_set
== ref1_alias_set
1094 || alias_set_subset_of (base2_alias_set
, ref1_alias_set
)))
1096 ++alias_stats
.aliasing_component_refs_p_may_alias
;
1099 ++alias_stats
.aliasing_component_refs_p_no_alias
;
1103 /* Return true if we can determine that component references REF1 and REF2,
1104 that are within a common DECL, cannot overlap. */
1107 nonoverlapping_component_refs_of_decl_p (tree ref1
, tree ref2
)
1109 auto_vec
<tree
, 16> component_refs1
;
1110 auto_vec
<tree
, 16> component_refs2
;
1112 /* Create the stack of handled components for REF1. */
1113 while (handled_component_p (ref1
))
1115 component_refs1
.safe_push (ref1
);
1116 ref1
= TREE_OPERAND (ref1
, 0);
1118 if (TREE_CODE (ref1
) == MEM_REF
)
1120 if (!integer_zerop (TREE_OPERAND (ref1
, 1)))
1122 ++alias_stats
.nonoverlapping_component_refs_of_decl_p_may_alias
;
1125 ref1
= TREE_OPERAND (TREE_OPERAND (ref1
, 0), 0);
1128 /* Create the stack of handled components for REF2. */
1129 while (handled_component_p (ref2
))
1131 component_refs2
.safe_push (ref2
);
1132 ref2
= TREE_OPERAND (ref2
, 0);
1134 if (TREE_CODE (ref2
) == MEM_REF
)
1136 if (!integer_zerop (TREE_OPERAND (ref2
, 1)))
1138 ++alias_stats
.nonoverlapping_component_refs_of_decl_p_may_alias
;
1141 ref2
= TREE_OPERAND (TREE_OPERAND (ref2
, 0), 0);
1144 /* Bases must be either same or uncomparable. */
1145 gcc_checking_assert (ref1
== ref2
1146 || (DECL_P (ref1
) && DECL_P (ref2
)
1147 && compare_base_decls (ref1
, ref2
) != 0));
1149 /* Pop the stacks in parallel and examine the COMPONENT_REFs of the same
1150 rank. This is sufficient because we start from the same DECL and you
1151 cannot reference several fields at a time with COMPONENT_REFs (unlike
1152 with ARRAY_RANGE_REFs for arrays) so you always need the same number
1153 of them to access a sub-component, unless you're in a union, in which
1154 case the return value will precisely be false. */
1159 if (component_refs1
.is_empty ())
1161 ++alias_stats
.nonoverlapping_component_refs_of_decl_p_may_alias
;
1164 ref1
= component_refs1
.pop ();
1166 while (!RECORD_OR_UNION_TYPE_P (TREE_TYPE (TREE_OPERAND (ref1
, 0))));
1170 if (component_refs2
.is_empty ())
1172 ++alias_stats
.nonoverlapping_component_refs_of_decl_p_may_alias
;
1175 ref2
= component_refs2
.pop ();
1177 while (!RECORD_OR_UNION_TYPE_P (TREE_TYPE (TREE_OPERAND (ref2
, 0))));
1179 /* Beware of BIT_FIELD_REF. */
1180 if (TREE_CODE (ref1
) != COMPONENT_REF
1181 || TREE_CODE (ref2
) != COMPONENT_REF
)
1183 ++alias_stats
.nonoverlapping_component_refs_of_decl_p_may_alias
;
1187 tree field1
= TREE_OPERAND (ref1
, 1);
1188 tree field2
= TREE_OPERAND (ref2
, 1);
1190 /* ??? We cannot simply use the type of operand #0 of the refs here
1191 as the Fortran compiler smuggles type punning into COMPONENT_REFs
1192 for common blocks instead of using unions like everyone else. */
1193 tree type1
= DECL_CONTEXT (field1
);
1194 tree type2
= DECL_CONTEXT (field2
);
1196 /* We cannot disambiguate fields in a union or qualified union. */
1197 if (type1
!= type2
|| TREE_CODE (type1
) != RECORD_TYPE
)
1199 ++alias_stats
.nonoverlapping_component_refs_of_decl_p_may_alias
;
1203 if (field1
!= field2
)
1205 /* A field and its representative need to be considered the
1207 if (DECL_BIT_FIELD_REPRESENTATIVE (field1
) == field2
1208 || DECL_BIT_FIELD_REPRESENTATIVE (field2
) == field1
)
1210 ++alias_stats
.nonoverlapping_component_refs_of_decl_p_may_alias
;
1213 /* Different fields of the same record type cannot overlap.
1214 ??? Bitfields can overlap at RTL level so punt on them. */
1215 if (DECL_BIT_FIELD (field1
) && DECL_BIT_FIELD (field2
))
1217 ++alias_stats
.nonoverlapping_component_refs_of_decl_p_may_alias
;
1220 ++alias_stats
.nonoverlapping_component_refs_of_decl_p_no_alias
;
1225 ++alias_stats
.nonoverlapping_component_refs_of_decl_p_may_alias
;
1229 /* qsort compare function to sort FIELD_DECLs after their
1230 DECL_FIELD_CONTEXT TYPE_UID. */
1233 ncr_compar (const void *field1_
, const void *field2_
)
1235 const_tree field1
= *(const_tree
*) const_cast <void *>(field1_
);
1236 const_tree field2
= *(const_tree
*) const_cast <void *>(field2_
);
1237 unsigned int uid1
= TYPE_UID (DECL_FIELD_CONTEXT (field1
));
1238 unsigned int uid2
= TYPE_UID (DECL_FIELD_CONTEXT (field2
));
1241 else if (uid1
> uid2
)
1246 /* Return true if we can determine that the fields referenced cannot
1247 overlap for any pair of objects. */
1250 nonoverlapping_component_refs_p (const_tree x
, const_tree y
)
1252 if (!flag_strict_aliasing
1254 || !handled_component_p (x
)
1255 || !handled_component_p (y
))
1257 ++alias_stats
.nonoverlapping_component_refs_p_may_alias
;
1261 auto_vec
<const_tree
, 16> fieldsx
;
1262 while (handled_component_p (x
))
1264 if (TREE_CODE (x
) == COMPONENT_REF
)
1266 tree field
= TREE_OPERAND (x
, 1);
1267 tree type
= DECL_FIELD_CONTEXT (field
);
1268 if (TREE_CODE (type
) == RECORD_TYPE
)
1269 fieldsx
.safe_push (field
);
1271 else if (TREE_CODE (x
) == VIEW_CONVERT_EXPR
)
1272 fieldsx
.truncate (0);
1273 x
= TREE_OPERAND (x
, 0);
1275 if (fieldsx
.length () == 0)
1277 auto_vec
<const_tree
, 16> fieldsy
;
1278 while (handled_component_p (y
))
1280 if (TREE_CODE (y
) == COMPONENT_REF
)
1282 tree field
= TREE_OPERAND (y
, 1);
1283 tree type
= DECL_FIELD_CONTEXT (field
);
1284 if (TREE_CODE (type
) == RECORD_TYPE
)
1285 fieldsy
.safe_push (TREE_OPERAND (y
, 1));
1287 else if (TREE_CODE (y
) == VIEW_CONVERT_EXPR
)
1288 fieldsy
.truncate (0);
1289 y
= TREE_OPERAND (y
, 0);
1291 if (fieldsy
.length () == 0)
1293 ++alias_stats
.nonoverlapping_component_refs_p_may_alias
;
1297 /* Most common case first. */
1298 if (fieldsx
.length () == 1
1299 && fieldsy
.length () == 1)
1301 if ((DECL_FIELD_CONTEXT (fieldsx
[0])
1302 == DECL_FIELD_CONTEXT (fieldsy
[0]))
1303 && fieldsx
[0] != fieldsy
[0]
1304 && !(DECL_BIT_FIELD (fieldsx
[0]) && DECL_BIT_FIELD (fieldsy
[0])))
1306 ++alias_stats
.nonoverlapping_component_refs_p_no_alias
;
1311 ++alias_stats
.nonoverlapping_component_refs_p_may_alias
;
1316 if (fieldsx
.length () == 2)
1318 if (ncr_compar (&fieldsx
[0], &fieldsx
[1]) == 1)
1319 std::swap (fieldsx
[0], fieldsx
[1]);
1322 fieldsx
.qsort (ncr_compar
);
1324 if (fieldsy
.length () == 2)
1326 if (ncr_compar (&fieldsy
[0], &fieldsy
[1]) == 1)
1327 std::swap (fieldsy
[0], fieldsy
[1]);
1330 fieldsy
.qsort (ncr_compar
);
1332 unsigned i
= 0, j
= 0;
1335 const_tree fieldx
= fieldsx
[i
];
1336 const_tree fieldy
= fieldsy
[j
];
1337 tree typex
= DECL_FIELD_CONTEXT (fieldx
);
1338 tree typey
= DECL_FIELD_CONTEXT (fieldy
);
1341 /* We're left with accessing different fields of a structure,
1342 no possible overlap. */
1343 if (fieldx
!= fieldy
)
1345 /* A field and its representative need to be considered the
1347 if (DECL_BIT_FIELD_REPRESENTATIVE (fieldx
) == fieldy
1348 || DECL_BIT_FIELD_REPRESENTATIVE (fieldy
) == fieldx
)
1350 ++alias_stats
.nonoverlapping_component_refs_p_may_alias
;
1353 /* Different fields of the same record type cannot overlap.
1354 ??? Bitfields can overlap at RTL level so punt on them. */
1355 if (DECL_BIT_FIELD (fieldx
) && DECL_BIT_FIELD (fieldy
))
1357 ++alias_stats
.nonoverlapping_component_refs_p_may_alias
;
1360 ++alias_stats
.nonoverlapping_component_refs_p_no_alias
;
1364 if (TYPE_UID (typex
) < TYPE_UID (typey
))
1367 if (i
== fieldsx
.length ())
1373 if (j
== fieldsy
.length ())
1379 ++alias_stats
.nonoverlapping_component_refs_p_may_alias
;
1384 /* Return true if two memory references based on the variables BASE1
1385 and BASE2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and
1386 [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. REF1 and REF2
1387 if non-NULL are the complete memory reference trees. */
1390 decl_refs_may_alias_p (tree ref1
, tree base1
,
1391 poly_int64 offset1
, poly_int64 max_size1
,
1392 tree ref2
, tree base2
,
1393 poly_int64 offset2
, poly_int64 max_size2
)
1395 gcc_checking_assert (DECL_P (base1
) && DECL_P (base2
));
1397 /* If both references are based on different variables, they cannot alias. */
1398 if (compare_base_decls (base1
, base2
) == 0)
1401 /* If both references are based on the same variable, they cannot alias if
1402 the accesses do not overlap. */
1403 if (!ranges_maybe_overlap_p (offset1
, max_size1
, offset2
, max_size2
))
1406 /* For components with variable position, the above test isn't sufficient,
1407 so we disambiguate component references manually. */
1409 && handled_component_p (ref1
) && handled_component_p (ref2
)
1410 && nonoverlapping_component_refs_of_decl_p (ref1
, ref2
))
1416 /* Return true if an indirect reference based on *PTR1 constrained
1417 to [OFFSET1, OFFSET1 + MAX_SIZE1) may alias a variable based on BASE2
1418 constrained to [OFFSET2, OFFSET2 + MAX_SIZE2). *PTR1 and BASE2 have
1419 the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1
1420 in which case they are computed on-demand. REF1 and REF2
1421 if non-NULL are the complete memory reference trees. */
1424 indirect_ref_may_alias_decl_p (tree ref1 ATTRIBUTE_UNUSED
, tree base1
,
1425 poly_int64 offset1
, poly_int64 max_size1
,
1426 alias_set_type ref1_alias_set
,
1427 alias_set_type base1_alias_set
,
1428 tree ref2 ATTRIBUTE_UNUSED
, tree base2
,
1429 poly_int64 offset2
, poly_int64 max_size2
,
1430 alias_set_type ref2_alias_set
,
1431 alias_set_type base2_alias_set
, bool tbaa_p
)
1434 tree ptrtype1
, dbase2
;
1436 gcc_checking_assert ((TREE_CODE (base1
) == MEM_REF
1437 || TREE_CODE (base1
) == TARGET_MEM_REF
)
1440 ptr1
= TREE_OPERAND (base1
, 0);
1441 poly_offset_int moff
= mem_ref_offset (base1
) << LOG2_BITS_PER_UNIT
;
1443 /* If only one reference is based on a variable, they cannot alias if
1444 the pointer access is beyond the extent of the variable access.
1445 (the pointer base cannot validly point to an offset less than zero
1447 ??? IVOPTs creates bases that do not honor this restriction,
1448 so do not apply this optimization for TARGET_MEM_REFs. */
1449 if (TREE_CODE (base1
) != TARGET_MEM_REF
1450 && !ranges_maybe_overlap_p (offset1
+ moff
, -1, offset2
, max_size2
))
1452 /* They also cannot alias if the pointer may not point to the decl. */
1453 if (!ptr_deref_may_alias_decl_p (ptr1
, base2
))
1456 /* Disambiguations that rely on strict aliasing rules follow. */
1457 if (!flag_strict_aliasing
|| !tbaa_p
)
1460 ptrtype1
= TREE_TYPE (TREE_OPERAND (base1
, 1));
1462 /* If the alias set for a pointer access is zero all bets are off. */
1463 if (base1_alias_set
== 0)
1466 /* When we are trying to disambiguate an access with a pointer dereference
1467 as base versus one with a decl as base we can use both the size
1468 of the decl and its dynamic type for extra disambiguation.
1469 ??? We do not know anything about the dynamic type of the decl
1470 other than that its alias-set contains base2_alias_set as a subset
1471 which does not help us here. */
1472 /* As we know nothing useful about the dynamic type of the decl just
1473 use the usual conflict check rather than a subset test.
1474 ??? We could introduce -fvery-strict-aliasing when the language
1475 does not allow decls to have a dynamic type that differs from their
1476 static type. Then we can check
1477 !alias_set_subset_of (base1_alias_set, base2_alias_set) instead. */
1478 if (base1_alias_set
!= base2_alias_set
1479 && !alias_sets_conflict_p (base1_alias_set
, base2_alias_set
))
1481 /* If the size of the access relevant for TBAA through the pointer
1482 is bigger than the size of the decl we can't possibly access the
1483 decl via that pointer. */
1484 if (/* ??? This in turn may run afoul when a decl of type T which is
1485 a member of union type U is accessed through a pointer to
1486 type U and sizeof T is smaller than sizeof U. */
1487 TREE_CODE (TREE_TYPE (ptrtype1
)) != UNION_TYPE
1488 && TREE_CODE (TREE_TYPE (ptrtype1
)) != QUAL_UNION_TYPE
1489 && compare_sizes (DECL_SIZE (base2
),
1490 TYPE_SIZE (TREE_TYPE (ptrtype1
))) < 0)
1496 /* If the decl is accessed via a MEM_REF, reconstruct the base
1497 we can use for TBAA and an appropriately adjusted offset. */
1499 while (handled_component_p (dbase2
))
1500 dbase2
= TREE_OPERAND (dbase2
, 0);
1501 poly_int64 doffset1
= offset1
;
1502 poly_offset_int doffset2
= offset2
;
1503 if (TREE_CODE (dbase2
) == MEM_REF
1504 || TREE_CODE (dbase2
) == TARGET_MEM_REF
)
1506 doffset2
-= mem_ref_offset (dbase2
) << LOG2_BITS_PER_UNIT
;
1507 tree ptrtype2
= TREE_TYPE (TREE_OPERAND (dbase2
, 1));
1508 /* If second reference is view-converted, give up now. */
1509 if (same_type_for_tbaa (TREE_TYPE (dbase2
), TREE_TYPE (ptrtype2
)) != 1)
1513 /* If first reference is view-converted, give up now. */
1514 if (same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (ptrtype1
)) != 1)
1517 /* If both references are through the same type, they do not alias
1518 if the accesses do not overlap. This does extra disambiguation
1519 for mixed/pointer accesses but requires strict aliasing.
1520 For MEM_REFs we require that the component-ref offset we computed
1521 is relative to the start of the type which we ensure by
1522 comparing rvalue and access type and disregarding the constant
1525 But avoid treating variable length arrays as "objects", instead assume they
1526 can overlap by an exact multiple of their element size.
1527 See gcc.dg/torture/alias-2.c. */
1528 if (((TREE_CODE (base1
) != TARGET_MEM_REF
1529 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1530 && (TREE_CODE (dbase2
) != TARGET_MEM_REF
1531 || (!TMR_INDEX (dbase2
) && !TMR_INDEX2 (base2
))))
1532 && same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (dbase2
)) == 1
1533 && (TREE_CODE (TREE_TYPE (base1
)) != ARRAY_TYPE
1534 || (TYPE_SIZE (TREE_TYPE (base1
))
1535 && TREE_CODE (TYPE_SIZE (TREE_TYPE (base1
))) == INTEGER_CST
))
1536 && !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
,
1552 /* Only if the other reference is actual
1553 decl we can safely check only toplevel
1554 part of access path 1. */
1555 same_type_for_tbaa (TREE_TYPE (dbase2
),
1562 /* Return true if two indirect references based on *PTR1
1563 and *PTR2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and
1564 [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. *PTR1 and *PTR2 have
1565 the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1
1566 in which case they are computed on-demand. REF1 and REF2
1567 if non-NULL are the complete memory reference trees. */
1570 indirect_refs_may_alias_p (tree ref1 ATTRIBUTE_UNUSED
, tree base1
,
1571 poly_int64 offset1
, poly_int64 max_size1
,
1572 alias_set_type ref1_alias_set
,
1573 alias_set_type base1_alias_set
,
1574 tree ref2 ATTRIBUTE_UNUSED
, tree base2
,
1575 poly_int64 offset2
, poly_int64 max_size2
,
1576 alias_set_type ref2_alias_set
,
1577 alias_set_type base2_alias_set
, bool tbaa_p
)
1581 tree ptrtype1
, ptrtype2
;
1583 gcc_checking_assert ((TREE_CODE (base1
) == MEM_REF
1584 || TREE_CODE (base1
) == TARGET_MEM_REF
)
1585 && (TREE_CODE (base2
) == MEM_REF
1586 || TREE_CODE (base2
) == TARGET_MEM_REF
));
1588 ptr1
= TREE_OPERAND (base1
, 0);
1589 ptr2
= TREE_OPERAND (base2
, 0);
1591 /* If both bases are based on pointers they cannot alias if they may not
1592 point to the same memory object or if they point to the same object
1593 and the accesses do not overlap. */
1594 if ((!cfun
|| gimple_in_ssa_p (cfun
))
1595 && operand_equal_p (ptr1
, ptr2
, 0)
1596 && (((TREE_CODE (base1
) != TARGET_MEM_REF
1597 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1598 && (TREE_CODE (base2
) != TARGET_MEM_REF
1599 || (!TMR_INDEX (base2
) && !TMR_INDEX2 (base2
))))
1600 || (TREE_CODE (base1
) == TARGET_MEM_REF
1601 && TREE_CODE (base2
) == TARGET_MEM_REF
1602 && (TMR_STEP (base1
) == TMR_STEP (base2
)
1603 || (TMR_STEP (base1
) && TMR_STEP (base2
)
1604 && operand_equal_p (TMR_STEP (base1
),
1605 TMR_STEP (base2
), 0)))
1606 && (TMR_INDEX (base1
) == TMR_INDEX (base2
)
1607 || (TMR_INDEX (base1
) && TMR_INDEX (base2
)
1608 && operand_equal_p (TMR_INDEX (base1
),
1609 TMR_INDEX (base2
), 0)))
1610 && (TMR_INDEX2 (base1
) == TMR_INDEX2 (base2
)
1611 || (TMR_INDEX2 (base1
) && TMR_INDEX2 (base2
)
1612 && operand_equal_p (TMR_INDEX2 (base1
),
1613 TMR_INDEX2 (base2
), 0))))))
1615 poly_offset_int moff1
= mem_ref_offset (base1
) << LOG2_BITS_PER_UNIT
;
1616 poly_offset_int moff2
= mem_ref_offset (base2
) << LOG2_BITS_PER_UNIT
;
1617 if (!ranges_maybe_overlap_p (offset1
+ moff1
, max_size1
,
1618 offset2
+ moff2
, max_size2
))
1621 if (!ptr_derefs_may_alias_p (ptr1
, ptr2
))
1624 /* Disambiguations that rely on strict aliasing rules follow. */
1625 if (!flag_strict_aliasing
|| !tbaa_p
)
1628 ptrtype1
= TREE_TYPE (TREE_OPERAND (base1
, 1));
1629 ptrtype2
= TREE_TYPE (TREE_OPERAND (base2
, 1));
1631 /* If the alias set for a pointer access is zero all bets are off. */
1632 if (base1_alias_set
== 0
1633 || base2_alias_set
== 0)
1636 /* Do type-based disambiguation. */
1637 if (base1_alias_set
!= base2_alias_set
1638 && !alias_sets_conflict_p (base1_alias_set
, base2_alias_set
))
1641 /* If either reference is view-converted, give up now. */
1642 if (same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (ptrtype1
)) != 1
1643 || same_type_for_tbaa (TREE_TYPE (base2
), TREE_TYPE (ptrtype2
)) != 1)
1646 /* If both references are through the same type, they do not alias
1647 if the accesses do not overlap. This does extra disambiguation
1648 for mixed/pointer accesses but requires strict aliasing. */
1649 if ((TREE_CODE (base1
) != TARGET_MEM_REF
1650 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1651 && (TREE_CODE (base2
) != TARGET_MEM_REF
1652 || (!TMR_INDEX (base2
) && !TMR_INDEX2 (base2
)))
1653 && same_type_for_tbaa (TREE_TYPE (ptrtype1
),
1654 TREE_TYPE (ptrtype2
)) == 1
1655 /* But avoid treating arrays as "objects", instead assume they
1656 can overlap by an exact multiple of their element size.
1657 See gcc.dg/torture/alias-2.c. */
1658 && TREE_CODE (TREE_TYPE (ptrtype1
)) != ARRAY_TYPE
1659 && !ranges_maybe_overlap_p (offset1
, max_size1
, offset2
, max_size2
))
1663 && nonoverlapping_component_refs_p (ref1
, ref2
))
1666 /* Do access-path based disambiguation. */
1668 && (handled_component_p (ref1
) || handled_component_p (ref2
)))
1669 return aliasing_component_refs_p (ref1
,
1670 ref1_alias_set
, base1_alias_set
,
1673 ref2_alias_set
, base2_alias_set
,
1674 offset2
, max_size2
, false);
1679 /* Return true, if the two memory references REF1 and REF2 may alias. */
1682 refs_may_alias_p_2 (ao_ref
*ref1
, ao_ref
*ref2
, bool tbaa_p
)
1685 poly_int64 offset1
= 0, offset2
= 0;
1686 poly_int64 max_size1
= -1, max_size2
= -1;
1687 bool var1_p
, var2_p
, ind1_p
, ind2_p
;
1689 gcc_checking_assert ((!ref1
->ref
1690 || TREE_CODE (ref1
->ref
) == SSA_NAME
1691 || DECL_P (ref1
->ref
)
1692 || TREE_CODE (ref1
->ref
) == STRING_CST
1693 || handled_component_p (ref1
->ref
)
1694 || TREE_CODE (ref1
->ref
) == MEM_REF
1695 || TREE_CODE (ref1
->ref
) == TARGET_MEM_REF
)
1697 || TREE_CODE (ref2
->ref
) == SSA_NAME
1698 || DECL_P (ref2
->ref
)
1699 || TREE_CODE (ref2
->ref
) == STRING_CST
1700 || handled_component_p (ref2
->ref
)
1701 || TREE_CODE (ref2
->ref
) == MEM_REF
1702 || TREE_CODE (ref2
->ref
) == TARGET_MEM_REF
));
1704 /* Decompose the references into their base objects and the access. */
1705 base1
= ao_ref_base (ref1
);
1706 offset1
= ref1
->offset
;
1707 max_size1
= ref1
->max_size
;
1708 base2
= ao_ref_base (ref2
);
1709 offset2
= ref2
->offset
;
1710 max_size2
= ref2
->max_size
;
1712 /* We can end up with registers or constants as bases for example from
1713 *D.1663_44 = VIEW_CONVERT_EXPR<struct DB_LSN>(__tmp$B0F64_59);
1714 which is seen as a struct copy. */
1715 if (TREE_CODE (base1
) == SSA_NAME
1716 || TREE_CODE (base1
) == CONST_DECL
1717 || TREE_CODE (base1
) == CONSTRUCTOR
1718 || TREE_CODE (base1
) == ADDR_EXPR
1719 || CONSTANT_CLASS_P (base1
)
1720 || TREE_CODE (base2
) == SSA_NAME
1721 || TREE_CODE (base2
) == CONST_DECL
1722 || TREE_CODE (base2
) == CONSTRUCTOR
1723 || TREE_CODE (base2
) == ADDR_EXPR
1724 || CONSTANT_CLASS_P (base2
))
1727 /* We can end up referring to code via function and label decls.
1728 As we likely do not properly track code aliases conservatively
1730 if (TREE_CODE (base1
) == FUNCTION_DECL
1731 || TREE_CODE (base1
) == LABEL_DECL
1732 || TREE_CODE (base2
) == FUNCTION_DECL
1733 || TREE_CODE (base2
) == LABEL_DECL
)
1736 /* Two volatile accesses always conflict. */
1737 if (ref1
->volatile_p
1738 && ref2
->volatile_p
)
1741 /* Defer to simple offset based disambiguation if we have
1742 references based on two decls. Do this before defering to
1743 TBAA to handle must-alias cases in conformance with the
1744 GCC extension of allowing type-punning through unions. */
1745 var1_p
= DECL_P (base1
);
1746 var2_p
= DECL_P (base2
);
1747 if (var1_p
&& var2_p
)
1748 return decl_refs_may_alias_p (ref1
->ref
, base1
, offset1
, max_size1
,
1749 ref2
->ref
, base2
, offset2
, max_size2
);
1751 /* Handle restrict based accesses.
1752 ??? ao_ref_base strips inner MEM_REF [&decl], recover from that
1754 tree rbase1
= base1
;
1755 tree rbase2
= base2
;
1760 while (handled_component_p (rbase1
))
1761 rbase1
= TREE_OPERAND (rbase1
, 0);
1767 while (handled_component_p (rbase2
))
1768 rbase2
= TREE_OPERAND (rbase2
, 0);
1770 if (rbase1
&& rbase2
1771 && (TREE_CODE (base1
) == MEM_REF
|| TREE_CODE (base1
) == TARGET_MEM_REF
)
1772 && (TREE_CODE (base2
) == MEM_REF
|| TREE_CODE (base2
) == TARGET_MEM_REF
)
1773 /* If the accesses are in the same restrict clique... */
1774 && MR_DEPENDENCE_CLIQUE (base1
) == MR_DEPENDENCE_CLIQUE (base2
)
1775 /* But based on different pointers they do not alias. */
1776 && MR_DEPENDENCE_BASE (base1
) != MR_DEPENDENCE_BASE (base2
))
1779 ind1_p
= (TREE_CODE (base1
) == MEM_REF
1780 || TREE_CODE (base1
) == TARGET_MEM_REF
);
1781 ind2_p
= (TREE_CODE (base2
) == MEM_REF
1782 || TREE_CODE (base2
) == TARGET_MEM_REF
);
1784 /* Canonicalize the pointer-vs-decl case. */
1785 if (ind1_p
&& var2_p
)
1787 std::swap (offset1
, offset2
);
1788 std::swap (max_size1
, max_size2
);
1789 std::swap (base1
, base2
);
1790 std::swap (ref1
, ref2
);
1797 /* First defer to TBAA if possible. */
1799 && flag_strict_aliasing
1800 && !alias_sets_conflict_p (ao_ref_alias_set (ref1
),
1801 ao_ref_alias_set (ref2
)))
1804 /* If the reference is based on a pointer that points to memory
1805 that may not be written to then the other reference cannot possibly
1807 if ((TREE_CODE (TREE_OPERAND (base2
, 0)) == SSA_NAME
1808 && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base2
, 0)))
1810 && TREE_CODE (TREE_OPERAND (base1
, 0)) == SSA_NAME
1811 && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base1
, 0))))
1814 /* Dispatch to the pointer-vs-decl or pointer-vs-pointer disambiguators. */
1815 if (var1_p
&& ind2_p
)
1816 return indirect_ref_may_alias_decl_p (ref2
->ref
, base2
,
1818 ao_ref_alias_set (ref2
),
1819 ao_ref_base_alias_set (ref2
),
1822 ao_ref_alias_set (ref1
),
1823 ao_ref_base_alias_set (ref1
),
1825 else if (ind1_p
&& ind2_p
)
1826 return indirect_refs_may_alias_p (ref1
->ref
, base1
,
1828 ao_ref_alias_set (ref1
),
1829 ao_ref_base_alias_set (ref1
),
1832 ao_ref_alias_set (ref2
),
1833 ao_ref_base_alias_set (ref2
),
1839 /* Return true, if the two memory references REF1 and REF2 may alias
1840 and update statistics. */
1843 refs_may_alias_p_1 (ao_ref
*ref1
, ao_ref
*ref2
, bool tbaa_p
)
1845 bool res
= refs_may_alias_p_2 (ref1
, ref2
, tbaa_p
);
1847 ++alias_stats
.refs_may_alias_p_may_alias
;
1849 ++alias_stats
.refs_may_alias_p_no_alias
;
1854 refs_may_alias_p (tree ref1
, ao_ref
*ref2
, bool tbaa_p
)
1857 ao_ref_init (&r1
, ref1
);
1858 return refs_may_alias_p_1 (&r1
, ref2
, tbaa_p
);
1862 refs_may_alias_p (tree ref1
, tree ref2
, bool tbaa_p
)
1865 ao_ref_init (&r1
, ref1
);
1866 ao_ref_init (&r2
, ref2
);
1867 return refs_may_alias_p_1 (&r1
, &r2
, tbaa_p
);
1870 /* Returns true if there is a anti-dependence for the STORE that
1871 executes after the LOAD. */
1874 refs_anti_dependent_p (tree load
, tree store
)
1877 ao_ref_init (&r1
, load
);
1878 ao_ref_init (&r2
, store
);
1879 return refs_may_alias_p_1 (&r1
, &r2
, false);
1882 /* Returns true if there is a output dependence for the stores
1883 STORE1 and STORE2. */
1886 refs_output_dependent_p (tree store1
, tree store2
)
1889 ao_ref_init (&r1
, store1
);
1890 ao_ref_init (&r2
, store2
);
1891 return refs_may_alias_p_1 (&r1
, &r2
, false);
1894 /* If the call CALL may use the memory reference REF return true,
1895 otherwise return false. */
1898 ref_maybe_used_by_call_p_1 (gcall
*call
, ao_ref
*ref
, bool tbaa_p
)
1902 int flags
= gimple_call_flags (call
);
1904 /* Const functions without a static chain do not implicitly use memory. */
1905 if (!gimple_call_chain (call
)
1906 && (flags
& (ECF_CONST
|ECF_NOVOPS
)))
1909 base
= ao_ref_base (ref
);
1913 /* A call that is not without side-effects might involve volatile
1914 accesses and thus conflicts with all other volatile accesses. */
1915 if (ref
->volatile_p
)
1918 /* If the reference is based on a decl that is not aliased the call
1919 cannot possibly use it. */
1921 && !may_be_aliased (base
)
1922 /* But local statics can be used through recursion. */
1923 && !is_global_var (base
))
1926 callee
= gimple_call_fndecl (call
);
1928 /* Handle those builtin functions explicitly that do not act as
1929 escape points. See tree-ssa-structalias.c:find_func_aliases
1930 for the list of builtins we might need to handle here. */
1931 if (callee
!= NULL_TREE
1932 && gimple_call_builtin_p (call
, BUILT_IN_NORMAL
))
1933 switch (DECL_FUNCTION_CODE (callee
))
1935 /* All the following functions read memory pointed to by
1936 their second argument. strcat/strncat additionally
1937 reads memory pointed to by the first argument. */
1938 case BUILT_IN_STRCAT
:
1939 case BUILT_IN_STRNCAT
:
1942 ao_ref_init_from_ptr_and_size (&dref
,
1943 gimple_call_arg (call
, 0),
1945 if (refs_may_alias_p_1 (&dref
, ref
, false))
1949 case BUILT_IN_STRCPY
:
1950 case BUILT_IN_STRNCPY
:
1951 case BUILT_IN_MEMCPY
:
1952 case BUILT_IN_MEMMOVE
:
1953 case BUILT_IN_MEMPCPY
:
1954 case BUILT_IN_STPCPY
:
1955 case BUILT_IN_STPNCPY
:
1956 case BUILT_IN_TM_MEMCPY
:
1957 case BUILT_IN_TM_MEMMOVE
:
1960 tree size
= NULL_TREE
;
1961 if (gimple_call_num_args (call
) == 3)
1962 size
= gimple_call_arg (call
, 2);
1963 ao_ref_init_from_ptr_and_size (&dref
,
1964 gimple_call_arg (call
, 1),
1966 return refs_may_alias_p_1 (&dref
, ref
, false);
1968 case BUILT_IN_STRCAT_CHK
:
1969 case BUILT_IN_STRNCAT_CHK
:
1972 ao_ref_init_from_ptr_and_size (&dref
,
1973 gimple_call_arg (call
, 0),
1975 if (refs_may_alias_p_1 (&dref
, ref
, false))
1979 case BUILT_IN_STRCPY_CHK
:
1980 case BUILT_IN_STRNCPY_CHK
:
1981 case BUILT_IN_MEMCPY_CHK
:
1982 case BUILT_IN_MEMMOVE_CHK
:
1983 case BUILT_IN_MEMPCPY_CHK
:
1984 case BUILT_IN_STPCPY_CHK
:
1985 case BUILT_IN_STPNCPY_CHK
:
1988 tree size
= NULL_TREE
;
1989 if (gimple_call_num_args (call
) == 4)
1990 size
= gimple_call_arg (call
, 2);
1991 ao_ref_init_from_ptr_and_size (&dref
,
1992 gimple_call_arg (call
, 1),
1994 return refs_may_alias_p_1 (&dref
, ref
, false);
1996 case BUILT_IN_BCOPY
:
1999 tree size
= gimple_call_arg (call
, 2);
2000 ao_ref_init_from_ptr_and_size (&dref
,
2001 gimple_call_arg (call
, 0),
2003 return refs_may_alias_p_1 (&dref
, ref
, false);
2006 /* The following functions read memory pointed to by their
2008 CASE_BUILT_IN_TM_LOAD (1):
2009 CASE_BUILT_IN_TM_LOAD (2):
2010 CASE_BUILT_IN_TM_LOAD (4):
2011 CASE_BUILT_IN_TM_LOAD (8):
2012 CASE_BUILT_IN_TM_LOAD (FLOAT
):
2013 CASE_BUILT_IN_TM_LOAD (DOUBLE
):
2014 CASE_BUILT_IN_TM_LOAD (LDOUBLE
):
2015 CASE_BUILT_IN_TM_LOAD (M64
):
2016 CASE_BUILT_IN_TM_LOAD (M128
):
2017 CASE_BUILT_IN_TM_LOAD (M256
):
2018 case BUILT_IN_TM_LOG
:
2019 case BUILT_IN_TM_LOG_1
:
2020 case BUILT_IN_TM_LOG_2
:
2021 case BUILT_IN_TM_LOG_4
:
2022 case BUILT_IN_TM_LOG_8
:
2023 case BUILT_IN_TM_LOG_FLOAT
:
2024 case BUILT_IN_TM_LOG_DOUBLE
:
2025 case BUILT_IN_TM_LOG_LDOUBLE
:
2026 case BUILT_IN_TM_LOG_M64
:
2027 case BUILT_IN_TM_LOG_M128
:
2028 case BUILT_IN_TM_LOG_M256
:
2029 return ptr_deref_may_alias_ref_p_1 (gimple_call_arg (call
, 0), ref
);
2031 /* These read memory pointed to by the first argument. */
2032 case BUILT_IN_STRDUP
:
2033 case BUILT_IN_STRNDUP
:
2034 case BUILT_IN_REALLOC
:
2037 tree size
= NULL_TREE
;
2038 if (gimple_call_num_args (call
) == 2)
2039 size
= gimple_call_arg (call
, 1);
2040 ao_ref_init_from_ptr_and_size (&dref
,
2041 gimple_call_arg (call
, 0),
2043 return refs_may_alias_p_1 (&dref
, ref
, false);
2045 /* These read memory pointed to by the first argument. */
2046 case BUILT_IN_INDEX
:
2047 case BUILT_IN_STRCHR
:
2048 case BUILT_IN_STRRCHR
:
2051 ao_ref_init_from_ptr_and_size (&dref
,
2052 gimple_call_arg (call
, 0),
2054 return refs_may_alias_p_1 (&dref
, ref
, false);
2056 /* These read memory pointed to by the first argument with size
2057 in the third argument. */
2058 case BUILT_IN_MEMCHR
:
2061 ao_ref_init_from_ptr_and_size (&dref
,
2062 gimple_call_arg (call
, 0),
2063 gimple_call_arg (call
, 2));
2064 return refs_may_alias_p_1 (&dref
, ref
, false);
2066 /* These read memory pointed to by the first and second arguments. */
2067 case BUILT_IN_STRSTR
:
2068 case BUILT_IN_STRPBRK
:
2071 ao_ref_init_from_ptr_and_size (&dref
,
2072 gimple_call_arg (call
, 0),
2074 if (refs_may_alias_p_1 (&dref
, ref
, false))
2076 ao_ref_init_from_ptr_and_size (&dref
,
2077 gimple_call_arg (call
, 1),
2079 return refs_may_alias_p_1 (&dref
, ref
, false);
2082 /* The following builtins do not read from memory. */
2084 case BUILT_IN_MALLOC
:
2085 case BUILT_IN_POSIX_MEMALIGN
:
2086 case BUILT_IN_ALIGNED_ALLOC
:
2087 case BUILT_IN_CALLOC
:
2088 CASE_BUILT_IN_ALLOCA
:
2089 case BUILT_IN_STACK_SAVE
:
2090 case BUILT_IN_STACK_RESTORE
:
2091 case BUILT_IN_MEMSET
:
2092 case BUILT_IN_TM_MEMSET
:
2093 case BUILT_IN_MEMSET_CHK
:
2094 case BUILT_IN_FREXP
:
2095 case BUILT_IN_FREXPF
:
2096 case BUILT_IN_FREXPL
:
2097 case BUILT_IN_GAMMA_R
:
2098 case BUILT_IN_GAMMAF_R
:
2099 case BUILT_IN_GAMMAL_R
:
2100 case BUILT_IN_LGAMMA_R
:
2101 case BUILT_IN_LGAMMAF_R
:
2102 case BUILT_IN_LGAMMAL_R
:
2104 case BUILT_IN_MODFF
:
2105 case BUILT_IN_MODFL
:
2106 case BUILT_IN_REMQUO
:
2107 case BUILT_IN_REMQUOF
:
2108 case BUILT_IN_REMQUOL
:
2109 case BUILT_IN_SINCOS
:
2110 case BUILT_IN_SINCOSF
:
2111 case BUILT_IN_SINCOSL
:
2112 case BUILT_IN_ASSUME_ALIGNED
:
2113 case BUILT_IN_VA_END
:
2115 /* __sync_* builtins and some OpenMP builtins act as threading
2117 #undef DEF_SYNC_BUILTIN
2118 #define DEF_SYNC_BUILTIN(ENUM, NAME, TYPE, ATTRS) case ENUM:
2119 #include "sync-builtins.def"
2120 #undef DEF_SYNC_BUILTIN
2121 case BUILT_IN_GOMP_ATOMIC_START
:
2122 case BUILT_IN_GOMP_ATOMIC_END
:
2123 case BUILT_IN_GOMP_BARRIER
:
2124 case BUILT_IN_GOMP_BARRIER_CANCEL
:
2125 case BUILT_IN_GOMP_TASKWAIT
:
2126 case BUILT_IN_GOMP_TASKGROUP_END
:
2127 case BUILT_IN_GOMP_CRITICAL_START
:
2128 case BUILT_IN_GOMP_CRITICAL_END
:
2129 case BUILT_IN_GOMP_CRITICAL_NAME_START
:
2130 case BUILT_IN_GOMP_CRITICAL_NAME_END
:
2131 case BUILT_IN_GOMP_LOOP_END
:
2132 case BUILT_IN_GOMP_LOOP_END_CANCEL
:
2133 case BUILT_IN_GOMP_ORDERED_START
:
2134 case BUILT_IN_GOMP_ORDERED_END
:
2135 case BUILT_IN_GOMP_SECTIONS_END
:
2136 case BUILT_IN_GOMP_SECTIONS_END_CANCEL
:
2137 case BUILT_IN_GOMP_SINGLE_COPY_START
:
2138 case BUILT_IN_GOMP_SINGLE_COPY_END
:
2142 /* Fallthru to general call handling. */;
2145 /* Check if base is a global static variable that is not read
2147 if (callee
!= NULL_TREE
&& VAR_P (base
) && TREE_STATIC (base
))
2149 struct cgraph_node
*node
= cgraph_node::get (callee
);
2152 /* FIXME: Callee can be an OMP builtin that does not have a call graph
2153 node yet. We should enforce that there are nodes for all decls in the
2154 IL and remove this check instead. */
2156 && (not_read
= ipa_reference_get_not_read_global (node
))
2157 && bitmap_bit_p (not_read
, ipa_reference_var_uid (base
)))
2161 /* Check if the base variable is call-used. */
2164 if (pt_solution_includes (gimple_call_use_set (call
), base
))
2167 else if ((TREE_CODE (base
) == MEM_REF
2168 || TREE_CODE (base
) == TARGET_MEM_REF
)
2169 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
)
2171 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (TREE_OPERAND (base
, 0));
2175 if (pt_solutions_intersect (gimple_call_use_set (call
), &pi
->pt
))
2181 /* Inspect call arguments for passed-by-value aliases. */
2183 for (i
= 0; i
< gimple_call_num_args (call
); ++i
)
2185 tree op
= gimple_call_arg (call
, i
);
2186 int flags
= gimple_call_arg_flags (call
, i
);
2188 if (flags
& EAF_UNUSED
)
2191 if (TREE_CODE (op
) == WITH_SIZE_EXPR
)
2192 op
= TREE_OPERAND (op
, 0);
2194 if (TREE_CODE (op
) != SSA_NAME
2195 && !is_gimple_min_invariant (op
))
2198 ao_ref_init (&r
, op
);
2199 if (refs_may_alias_p_1 (&r
, ref
, tbaa_p
))
2208 ref_maybe_used_by_call_p (gcall
*call
, ao_ref
*ref
, bool tbaa_p
)
2211 res
= ref_maybe_used_by_call_p_1 (call
, ref
, tbaa_p
);
2213 ++alias_stats
.ref_maybe_used_by_call_p_may_alias
;
2215 ++alias_stats
.ref_maybe_used_by_call_p_no_alias
;
2220 /* If the statement STMT may use the memory reference REF return
2221 true, otherwise return false. */
2224 ref_maybe_used_by_stmt_p (gimple
*stmt
, ao_ref
*ref
, bool tbaa_p
)
2226 if (is_gimple_assign (stmt
))
2230 /* All memory assign statements are single. */
2231 if (!gimple_assign_single_p (stmt
))
2234 rhs
= gimple_assign_rhs1 (stmt
);
2235 if (is_gimple_reg (rhs
)
2236 || is_gimple_min_invariant (rhs
)
2237 || gimple_assign_rhs_code (stmt
) == CONSTRUCTOR
)
2240 return refs_may_alias_p (rhs
, ref
, tbaa_p
);
2242 else if (is_gimple_call (stmt
))
2243 return ref_maybe_used_by_call_p (as_a
<gcall
*> (stmt
), ref
, tbaa_p
);
2244 else if (greturn
*return_stmt
= dyn_cast
<greturn
*> (stmt
))
2246 tree retval
= gimple_return_retval (return_stmt
);
2248 && TREE_CODE (retval
) != SSA_NAME
2249 && !is_gimple_min_invariant (retval
)
2250 && refs_may_alias_p (retval
, ref
, tbaa_p
))
2252 /* If ref escapes the function then the return acts as a use. */
2253 tree base
= ao_ref_base (ref
);
2256 else if (DECL_P (base
))
2257 return is_global_var (base
);
2258 else if (TREE_CODE (base
) == MEM_REF
2259 || TREE_CODE (base
) == TARGET_MEM_REF
)
2260 return ptr_deref_may_alias_global_p (TREE_OPERAND (base
, 0));
2268 ref_maybe_used_by_stmt_p (gimple
*stmt
, tree ref
, bool tbaa_p
)
2271 ao_ref_init (&r
, ref
);
2272 return ref_maybe_used_by_stmt_p (stmt
, &r
, tbaa_p
);
2275 /* If the call in statement CALL may clobber the memory reference REF
2276 return true, otherwise return false. */
2279 call_may_clobber_ref_p_1 (gcall
*call
, ao_ref
*ref
)
2284 /* If the call is pure or const it cannot clobber anything. */
2285 if (gimple_call_flags (call
)
2286 & (ECF_PURE
|ECF_CONST
|ECF_LOOPING_CONST_OR_PURE
|ECF_NOVOPS
))
2288 if (gimple_call_internal_p (call
))
2289 switch (gimple_call_internal_fn (call
))
2291 /* Treat these internal calls like ECF_PURE for aliasing,
2292 they don't write to any memory the program should care about.
2293 They have important other side-effects, and read memory,
2294 so can't be ECF_NOVOPS. */
2295 case IFN_UBSAN_NULL
:
2296 case IFN_UBSAN_BOUNDS
:
2297 case IFN_UBSAN_VPTR
:
2298 case IFN_UBSAN_OBJECT_SIZE
:
2300 case IFN_ASAN_CHECK
:
2306 base
= ao_ref_base (ref
);
2310 if (TREE_CODE (base
) == SSA_NAME
2311 || CONSTANT_CLASS_P (base
))
2314 /* A call that is not without side-effects might involve volatile
2315 accesses and thus conflicts with all other volatile accesses. */
2316 if (ref
->volatile_p
)
2319 /* If the reference is based on a decl that is not aliased the call
2320 cannot possibly clobber it. */
2322 && !may_be_aliased (base
)
2323 /* But local non-readonly statics can be modified through recursion
2324 or the call may implement a threading barrier which we must
2325 treat as may-def. */
2326 && (TREE_READONLY (base
)
2327 || !is_global_var (base
)))
2330 /* If the reference is based on a pointer that points to memory
2331 that may not be written to then the call cannot possibly clobber it. */
2332 if ((TREE_CODE (base
) == MEM_REF
2333 || TREE_CODE (base
) == TARGET_MEM_REF
)
2334 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
2335 && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base
, 0)))
2338 callee
= gimple_call_fndecl (call
);
2340 /* Handle those builtin functions explicitly that do not act as
2341 escape points. See tree-ssa-structalias.c:find_func_aliases
2342 for the list of builtins we might need to handle here. */
2343 if (callee
!= NULL_TREE
2344 && gimple_call_builtin_p (call
, BUILT_IN_NORMAL
))
2345 switch (DECL_FUNCTION_CODE (callee
))
2347 /* All the following functions clobber memory pointed to by
2348 their first argument. */
2349 case BUILT_IN_STRCPY
:
2350 case BUILT_IN_STRNCPY
:
2351 case BUILT_IN_MEMCPY
:
2352 case BUILT_IN_MEMMOVE
:
2353 case BUILT_IN_MEMPCPY
:
2354 case BUILT_IN_STPCPY
:
2355 case BUILT_IN_STPNCPY
:
2356 case BUILT_IN_STRCAT
:
2357 case BUILT_IN_STRNCAT
:
2358 case BUILT_IN_MEMSET
:
2359 case BUILT_IN_TM_MEMSET
:
2360 CASE_BUILT_IN_TM_STORE (1):
2361 CASE_BUILT_IN_TM_STORE (2):
2362 CASE_BUILT_IN_TM_STORE (4):
2363 CASE_BUILT_IN_TM_STORE (8):
2364 CASE_BUILT_IN_TM_STORE (FLOAT
):
2365 CASE_BUILT_IN_TM_STORE (DOUBLE
):
2366 CASE_BUILT_IN_TM_STORE (LDOUBLE
):
2367 CASE_BUILT_IN_TM_STORE (M64
):
2368 CASE_BUILT_IN_TM_STORE (M128
):
2369 CASE_BUILT_IN_TM_STORE (M256
):
2370 case BUILT_IN_TM_MEMCPY
:
2371 case BUILT_IN_TM_MEMMOVE
:
2374 tree size
= NULL_TREE
;
2375 /* Don't pass in size for strncat, as the maximum size
2376 is strlen (dest) + n + 1 instead of n, resp.
2377 n + 1 at dest + strlen (dest), but strlen (dest) isn't
2379 if (gimple_call_num_args (call
) == 3
2380 && DECL_FUNCTION_CODE (callee
) != BUILT_IN_STRNCAT
)
2381 size
= gimple_call_arg (call
, 2);
2382 ao_ref_init_from_ptr_and_size (&dref
,
2383 gimple_call_arg (call
, 0),
2385 return refs_may_alias_p_1 (&dref
, ref
, false);
2387 case BUILT_IN_STRCPY_CHK
:
2388 case BUILT_IN_STRNCPY_CHK
:
2389 case BUILT_IN_MEMCPY_CHK
:
2390 case BUILT_IN_MEMMOVE_CHK
:
2391 case BUILT_IN_MEMPCPY_CHK
:
2392 case BUILT_IN_STPCPY_CHK
:
2393 case BUILT_IN_STPNCPY_CHK
:
2394 case BUILT_IN_STRCAT_CHK
:
2395 case BUILT_IN_STRNCAT_CHK
:
2396 case BUILT_IN_MEMSET_CHK
:
2399 tree size
= NULL_TREE
;
2400 /* Don't pass in size for __strncat_chk, as the maximum size
2401 is strlen (dest) + n + 1 instead of n, resp.
2402 n + 1 at dest + strlen (dest), but strlen (dest) isn't
2404 if (gimple_call_num_args (call
) == 4
2405 && DECL_FUNCTION_CODE (callee
) != BUILT_IN_STRNCAT_CHK
)
2406 size
= gimple_call_arg (call
, 2);
2407 ao_ref_init_from_ptr_and_size (&dref
,
2408 gimple_call_arg (call
, 0),
2410 return refs_may_alias_p_1 (&dref
, ref
, false);
2412 case BUILT_IN_BCOPY
:
2415 tree size
= gimple_call_arg (call
, 2);
2416 ao_ref_init_from_ptr_and_size (&dref
,
2417 gimple_call_arg (call
, 1),
2419 return refs_may_alias_p_1 (&dref
, ref
, false);
2421 /* Allocating memory does not have any side-effects apart from
2422 being the definition point for the pointer. */
2423 case BUILT_IN_MALLOC
:
2424 case BUILT_IN_ALIGNED_ALLOC
:
2425 case BUILT_IN_CALLOC
:
2426 case BUILT_IN_STRDUP
:
2427 case BUILT_IN_STRNDUP
:
2428 /* Unix98 specifies that errno is set on allocation failure. */
2430 && targetm
.ref_may_alias_errno (ref
))
2433 case BUILT_IN_STACK_SAVE
:
2434 CASE_BUILT_IN_ALLOCA
:
2435 case BUILT_IN_ASSUME_ALIGNED
:
2437 /* But posix_memalign stores a pointer into the memory pointed to
2438 by its first argument. */
2439 case BUILT_IN_POSIX_MEMALIGN
:
2441 tree ptrptr
= gimple_call_arg (call
, 0);
2443 ao_ref_init_from_ptr_and_size (&dref
, ptrptr
,
2444 TYPE_SIZE_UNIT (ptr_type_node
));
2445 return (refs_may_alias_p_1 (&dref
, ref
, false)
2447 && targetm
.ref_may_alias_errno (ref
)));
2449 /* Freeing memory kills the pointed-to memory. More importantly
2450 the call has to serve as a barrier for moving loads and stores
2453 case BUILT_IN_VA_END
:
2455 tree ptr
= gimple_call_arg (call
, 0);
2456 return ptr_deref_may_alias_ref_p_1 (ptr
, ref
);
2458 /* Realloc serves both as allocation point and deallocation point. */
2459 case BUILT_IN_REALLOC
:
2461 tree ptr
= gimple_call_arg (call
, 0);
2462 /* Unix98 specifies that errno is set on allocation failure. */
2463 return ((flag_errno_math
2464 && targetm
.ref_may_alias_errno (ref
))
2465 || ptr_deref_may_alias_ref_p_1 (ptr
, ref
));
2467 case BUILT_IN_GAMMA_R
:
2468 case BUILT_IN_GAMMAF_R
:
2469 case BUILT_IN_GAMMAL_R
:
2470 case BUILT_IN_LGAMMA_R
:
2471 case BUILT_IN_LGAMMAF_R
:
2472 case BUILT_IN_LGAMMAL_R
:
2474 tree out
= gimple_call_arg (call
, 1);
2475 if (ptr_deref_may_alias_ref_p_1 (out
, ref
))
2477 if (flag_errno_math
)
2481 case BUILT_IN_FREXP
:
2482 case BUILT_IN_FREXPF
:
2483 case BUILT_IN_FREXPL
:
2485 case BUILT_IN_MODFF
:
2486 case BUILT_IN_MODFL
:
2488 tree out
= gimple_call_arg (call
, 1);
2489 return ptr_deref_may_alias_ref_p_1 (out
, ref
);
2491 case BUILT_IN_REMQUO
:
2492 case BUILT_IN_REMQUOF
:
2493 case BUILT_IN_REMQUOL
:
2495 tree out
= gimple_call_arg (call
, 2);
2496 if (ptr_deref_may_alias_ref_p_1 (out
, ref
))
2498 if (flag_errno_math
)
2502 case BUILT_IN_SINCOS
:
2503 case BUILT_IN_SINCOSF
:
2504 case BUILT_IN_SINCOSL
:
2506 tree sin
= gimple_call_arg (call
, 1);
2507 tree cos
= gimple_call_arg (call
, 2);
2508 return (ptr_deref_may_alias_ref_p_1 (sin
, ref
)
2509 || ptr_deref_may_alias_ref_p_1 (cos
, ref
));
2511 /* __sync_* builtins and some OpenMP builtins act as threading
2513 #undef DEF_SYNC_BUILTIN
2514 #define DEF_SYNC_BUILTIN(ENUM, NAME, TYPE, ATTRS) case ENUM:
2515 #include "sync-builtins.def"
2516 #undef DEF_SYNC_BUILTIN
2517 case BUILT_IN_GOMP_ATOMIC_START
:
2518 case BUILT_IN_GOMP_ATOMIC_END
:
2519 case BUILT_IN_GOMP_BARRIER
:
2520 case BUILT_IN_GOMP_BARRIER_CANCEL
:
2521 case BUILT_IN_GOMP_TASKWAIT
:
2522 case BUILT_IN_GOMP_TASKGROUP_END
:
2523 case BUILT_IN_GOMP_CRITICAL_START
:
2524 case BUILT_IN_GOMP_CRITICAL_END
:
2525 case BUILT_IN_GOMP_CRITICAL_NAME_START
:
2526 case BUILT_IN_GOMP_CRITICAL_NAME_END
:
2527 case BUILT_IN_GOMP_LOOP_END
:
2528 case BUILT_IN_GOMP_LOOP_END_CANCEL
:
2529 case BUILT_IN_GOMP_ORDERED_START
:
2530 case BUILT_IN_GOMP_ORDERED_END
:
2531 case BUILT_IN_GOMP_SECTIONS_END
:
2532 case BUILT_IN_GOMP_SECTIONS_END_CANCEL
:
2533 case BUILT_IN_GOMP_SINGLE_COPY_START
:
2534 case BUILT_IN_GOMP_SINGLE_COPY_END
:
2537 /* Fallthru to general call handling. */;
2540 /* Check if base is a global static variable that is not written
2542 if (callee
!= NULL_TREE
&& VAR_P (base
) && TREE_STATIC (base
))
2544 struct cgraph_node
*node
= cgraph_node::get (callee
);
2548 && (not_written
= ipa_reference_get_not_written_global (node
))
2549 && bitmap_bit_p (not_written
, ipa_reference_var_uid (base
)))
2553 /* Check if the base variable is call-clobbered. */
2555 return pt_solution_includes (gimple_call_clobber_set (call
), base
);
2556 else if ((TREE_CODE (base
) == MEM_REF
2557 || TREE_CODE (base
) == TARGET_MEM_REF
)
2558 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
)
2560 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (TREE_OPERAND (base
, 0));
2564 return pt_solutions_intersect (gimple_call_clobber_set (call
), &pi
->pt
);
2570 /* If the call in statement CALL may clobber the memory reference REF
2571 return true, otherwise return false. */
2574 call_may_clobber_ref_p (gcall
*call
, tree ref
)
2578 ao_ref_init (&r
, ref
);
2579 res
= call_may_clobber_ref_p_1 (call
, &r
);
2581 ++alias_stats
.call_may_clobber_ref_p_may_alias
;
2583 ++alias_stats
.call_may_clobber_ref_p_no_alias
;
2588 /* If the statement STMT may clobber the memory reference REF return true,
2589 otherwise return false. */
2592 stmt_may_clobber_ref_p_1 (gimple
*stmt
, ao_ref
*ref
, bool tbaa_p
)
2594 if (is_gimple_call (stmt
))
2596 tree lhs
= gimple_call_lhs (stmt
);
2598 && TREE_CODE (lhs
) != SSA_NAME
)
2601 ao_ref_init (&r
, lhs
);
2602 if (refs_may_alias_p_1 (ref
, &r
, tbaa_p
))
2606 return call_may_clobber_ref_p_1 (as_a
<gcall
*> (stmt
), ref
);
2608 else if (gimple_assign_single_p (stmt
))
2610 tree lhs
= gimple_assign_lhs (stmt
);
2611 if (TREE_CODE (lhs
) != SSA_NAME
)
2614 ao_ref_init (&r
, lhs
);
2615 return refs_may_alias_p_1 (ref
, &r
, tbaa_p
);
2618 else if (gimple_code (stmt
) == GIMPLE_ASM
)
2625 stmt_may_clobber_ref_p (gimple
*stmt
, tree ref
, bool tbaa_p
)
2628 ao_ref_init (&r
, ref
);
2629 return stmt_may_clobber_ref_p_1 (stmt
, &r
, tbaa_p
);
2632 /* Return true if store1 and store2 described by corresponding tuples
2633 <BASE, OFFSET, SIZE, MAX_SIZE> have the same size and store to the same
2637 same_addr_size_stores_p (tree base1
, poly_int64 offset1
, poly_int64 size1
,
2638 poly_int64 max_size1
,
2639 tree base2
, poly_int64 offset2
, poly_int64 size2
,
2640 poly_int64 max_size2
)
2642 /* Offsets need to be 0. */
2643 if (maybe_ne (offset1
, 0)
2644 || maybe_ne (offset2
, 0))
2647 bool base1_obj_p
= SSA_VAR_P (base1
);
2648 bool base2_obj_p
= SSA_VAR_P (base2
);
2650 /* We need one object. */
2651 if (base1_obj_p
== base2_obj_p
)
2653 tree obj
= base1_obj_p
? base1
: base2
;
2655 /* And we need one MEM_REF. */
2656 bool base1_memref_p
= TREE_CODE (base1
) == MEM_REF
;
2657 bool base2_memref_p
= TREE_CODE (base2
) == MEM_REF
;
2658 if (base1_memref_p
== base2_memref_p
)
2660 tree memref
= base1_memref_p
? base1
: base2
;
2662 /* Sizes need to be valid. */
2663 if (!known_size_p (max_size1
)
2664 || !known_size_p (max_size2
)
2665 || !known_size_p (size1
)
2666 || !known_size_p (size2
))
2669 /* Max_size needs to match size. */
2670 if (maybe_ne (max_size1
, size1
)
2671 || maybe_ne (max_size2
, size2
))
2674 /* Sizes need to match. */
2675 if (maybe_ne (size1
, size2
))
2679 /* Check that memref is a store to pointer with singleton points-to info. */
2680 if (!integer_zerop (TREE_OPERAND (memref
, 1)))
2682 tree ptr
= TREE_OPERAND (memref
, 0);
2683 if (TREE_CODE (ptr
) != SSA_NAME
)
2685 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (ptr
);
2686 unsigned int pt_uid
;
2688 || !pt_solution_singleton_or_null_p (&pi
->pt
, &pt_uid
))
2691 /* Be conservative with non-call exceptions when the address might
2693 if (cfun
->can_throw_non_call_exceptions
&& pi
->pt
.null
)
2696 /* Check that ptr points relative to obj. */
2697 unsigned int obj_uid
= DECL_PT_UID (obj
);
2698 if (obj_uid
!= pt_uid
)
2701 /* Check that the object size is the same as the store size. That ensures us
2702 that ptr points to the start of obj. */
2703 return (DECL_SIZE (obj
)
2704 && poly_int_tree_p (DECL_SIZE (obj
))
2705 && known_eq (wi::to_poly_offset (DECL_SIZE (obj
)), size1
));
2708 /* If STMT kills the memory reference REF return true, otherwise
2712 stmt_kills_ref_p (gimple
*stmt
, ao_ref
*ref
)
2714 if (!ao_ref_base (ref
))
2717 if (gimple_has_lhs (stmt
)
2718 && TREE_CODE (gimple_get_lhs (stmt
)) != SSA_NAME
2719 /* The assignment is not necessarily carried out if it can throw
2720 and we can catch it in the current function where we could inspect
2722 ??? We only need to care about the RHS throwing. For aggregate
2723 assignments or similar calls and non-call exceptions the LHS
2724 might throw as well. */
2725 && !stmt_can_throw_internal (cfun
, stmt
))
2727 tree lhs
= gimple_get_lhs (stmt
);
2728 /* If LHS is literally a base of the access we are done. */
2731 tree base
= ref
->ref
;
2732 tree innermost_dropped_array_ref
= NULL_TREE
;
2733 if (handled_component_p (base
))
2735 tree saved_lhs0
= NULL_TREE
;
2736 if (handled_component_p (lhs
))
2738 saved_lhs0
= TREE_OPERAND (lhs
, 0);
2739 TREE_OPERAND (lhs
, 0) = integer_zero_node
;
2743 /* Just compare the outermost handled component, if
2744 they are equal we have found a possible common
2746 tree saved_base0
= TREE_OPERAND (base
, 0);
2747 TREE_OPERAND (base
, 0) = integer_zero_node
;
2748 bool res
= operand_equal_p (lhs
, base
, 0);
2749 TREE_OPERAND (base
, 0) = saved_base0
;
2752 /* Remember if we drop an array-ref that we need to
2753 double-check not being at struct end. */
2754 if (TREE_CODE (base
) == ARRAY_REF
2755 || TREE_CODE (base
) == ARRAY_RANGE_REF
)
2756 innermost_dropped_array_ref
= base
;
2757 /* Otherwise drop handled components of the access. */
2760 while (handled_component_p (base
));
2762 TREE_OPERAND (lhs
, 0) = saved_lhs0
;
2764 /* Finally check if the lhs has the same address and size as the
2765 base candidate of the access. Watch out if we have dropped
2766 an array-ref that was at struct end, this means ref->ref may
2767 be outside of the TYPE_SIZE of its base. */
2768 if ((! innermost_dropped_array_ref
2769 || ! array_at_struct_end_p (innermost_dropped_array_ref
))
2771 || (((TYPE_SIZE (TREE_TYPE (lhs
))
2772 == TYPE_SIZE (TREE_TYPE (base
)))
2773 || (TYPE_SIZE (TREE_TYPE (lhs
))
2774 && TYPE_SIZE (TREE_TYPE (base
))
2775 && operand_equal_p (TYPE_SIZE (TREE_TYPE (lhs
)),
2776 TYPE_SIZE (TREE_TYPE (base
)),
2778 && operand_equal_p (lhs
, base
,
2780 | OEP_MATCH_SIDE_EFFECTS
))))
2784 /* Now look for non-literal equal bases with the restriction of
2785 handling constant offset and size. */
2786 /* For a must-alias check we need to be able to constrain
2787 the access properly. */
2788 if (!ref
->max_size_known_p ())
2790 poly_int64 size
, offset
, max_size
, ref_offset
= ref
->offset
;
2792 tree base
= get_ref_base_and_extent (lhs
, &offset
, &size
, &max_size
,
2794 /* We can get MEM[symbol: sZ, index: D.8862_1] here,
2795 so base == ref->base does not always hold. */
2796 if (base
!= ref
->base
)
2798 /* Try using points-to info. */
2799 if (same_addr_size_stores_p (base
, offset
, size
, max_size
, ref
->base
,
2800 ref
->offset
, ref
->size
, ref
->max_size
))
2803 /* If both base and ref->base are MEM_REFs, only compare the
2804 first operand, and if the second operand isn't equal constant,
2805 try to add the offsets into offset and ref_offset. */
2806 if (TREE_CODE (base
) == MEM_REF
&& TREE_CODE (ref
->base
) == MEM_REF
2807 && TREE_OPERAND (base
, 0) == TREE_OPERAND (ref
->base
, 0))
2809 if (!tree_int_cst_equal (TREE_OPERAND (base
, 1),
2810 TREE_OPERAND (ref
->base
, 1)))
2812 poly_offset_int off1
= mem_ref_offset (base
);
2813 off1
<<= LOG2_BITS_PER_UNIT
;
2815 poly_offset_int off2
= mem_ref_offset (ref
->base
);
2816 off2
<<= LOG2_BITS_PER_UNIT
;
2818 if (!off1
.to_shwi (&offset
) || !off2
.to_shwi (&ref_offset
))
2825 /* For a must-alias check we need to be able to constrain
2826 the access properly. */
2827 if (known_eq (size
, max_size
)
2828 && known_subrange_p (ref_offset
, ref
->max_size
, offset
, size
))
2832 if (is_gimple_call (stmt
))
2834 tree callee
= gimple_call_fndecl (stmt
);
2835 if (callee
!= NULL_TREE
2836 && gimple_call_builtin_p (stmt
, BUILT_IN_NORMAL
))
2837 switch (DECL_FUNCTION_CODE (callee
))
2841 tree ptr
= gimple_call_arg (stmt
, 0);
2842 tree base
= ao_ref_base (ref
);
2843 if (base
&& TREE_CODE (base
) == MEM_REF
2844 && TREE_OPERAND (base
, 0) == ptr
)
2849 case BUILT_IN_MEMCPY
:
2850 case BUILT_IN_MEMPCPY
:
2851 case BUILT_IN_MEMMOVE
:
2852 case BUILT_IN_MEMSET
:
2853 case BUILT_IN_MEMCPY_CHK
:
2854 case BUILT_IN_MEMPCPY_CHK
:
2855 case BUILT_IN_MEMMOVE_CHK
:
2856 case BUILT_IN_MEMSET_CHK
:
2857 case BUILT_IN_STRNCPY
:
2858 case BUILT_IN_STPNCPY
:
2860 /* For a must-alias check we need to be able to constrain
2861 the access properly. */
2862 if (!ref
->max_size_known_p ())
2864 tree dest
= gimple_call_arg (stmt
, 0);
2865 tree len
= gimple_call_arg (stmt
, 2);
2866 if (!poly_int_tree_p (len
))
2868 tree rbase
= ref
->base
;
2869 poly_offset_int roffset
= ref
->offset
;
2871 ao_ref_init_from_ptr_and_size (&dref
, dest
, len
);
2872 tree base
= ao_ref_base (&dref
);
2873 poly_offset_int offset
= dref
.offset
;
2874 if (!base
|| !known_size_p (dref
.size
))
2876 if (TREE_CODE (base
) == MEM_REF
)
2878 if (TREE_CODE (rbase
) != MEM_REF
)
2880 // Compare pointers.
2881 offset
+= mem_ref_offset (base
) << LOG2_BITS_PER_UNIT
;
2882 roffset
+= mem_ref_offset (rbase
) << LOG2_BITS_PER_UNIT
;
2883 base
= TREE_OPERAND (base
, 0);
2884 rbase
= TREE_OPERAND (rbase
, 0);
2887 && known_subrange_p (roffset
, ref
->max_size
, offset
,
2888 wi::to_poly_offset (len
)
2889 << LOG2_BITS_PER_UNIT
))
2894 case BUILT_IN_VA_END
:
2896 tree ptr
= gimple_call_arg (stmt
, 0);
2897 if (TREE_CODE (ptr
) == ADDR_EXPR
)
2899 tree base
= ao_ref_base (ref
);
2900 if (TREE_OPERAND (ptr
, 0) == base
)
2913 stmt_kills_ref_p (gimple
*stmt
, tree ref
)
2916 ao_ref_init (&r
, ref
);
2917 return stmt_kills_ref_p (stmt
, &r
);
2921 /* Walk the virtual use-def chain of VUSE until hitting the virtual operand
2922 TARGET or a statement clobbering the memory reference REF in which
2923 case false is returned. The walk starts with VUSE, one argument of PHI. */
2926 maybe_skip_until (gimple
*phi
, tree
&target
, basic_block target_bb
,
2927 ao_ref
*ref
, tree vuse
, unsigned int &limit
, bitmap
*visited
,
2928 bool abort_on_visited
,
2929 void *(*translate
)(ao_ref
*, tree
, void *, bool *),
2932 basic_block bb
= gimple_bb (phi
);
2935 *visited
= BITMAP_ALLOC (NULL
);
2937 bitmap_set_bit (*visited
, SSA_NAME_VERSION (PHI_RESULT (phi
)));
2939 /* Walk until we hit the target. */
2940 while (vuse
!= target
)
2942 gimple
*def_stmt
= SSA_NAME_DEF_STMT (vuse
);
2943 /* If we are searching for the target VUSE by walking up to
2944 TARGET_BB dominating the original PHI we are finished once
2945 we reach a default def or a definition in a block dominating
2946 that block. Update TARGET and return. */
2948 && (gimple_nop_p (def_stmt
)
2949 || dominated_by_p (CDI_DOMINATORS
,
2950 target_bb
, gimple_bb (def_stmt
))))
2956 /* Recurse for PHI nodes. */
2957 if (gimple_code (def_stmt
) == GIMPLE_PHI
)
2959 /* An already visited PHI node ends the walk successfully. */
2960 if (bitmap_bit_p (*visited
, SSA_NAME_VERSION (PHI_RESULT (def_stmt
))))
2961 return !abort_on_visited
;
2962 vuse
= get_continuation_for_phi (def_stmt
, ref
, limit
,
2963 visited
, abort_on_visited
,
2969 else if (gimple_nop_p (def_stmt
))
2973 /* A clobbering statement or the end of the IL ends it failing. */
2974 if ((int)limit
<= 0)
2977 if (stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
2979 bool disambiguate_only
= true;
2981 && (*translate
) (ref
, vuse
, data
, &disambiguate_only
) == NULL
)
2987 /* If we reach a new basic-block see if we already skipped it
2988 in a previous walk that ended successfully. */
2989 if (gimple_bb (def_stmt
) != bb
)
2991 if (!bitmap_set_bit (*visited
, SSA_NAME_VERSION (vuse
)))
2992 return !abort_on_visited
;
2993 bb
= gimple_bb (def_stmt
);
2995 vuse
= gimple_vuse (def_stmt
);
3001 /* Starting from a PHI node for the virtual operand of the memory reference
3002 REF find a continuation virtual operand that allows to continue walking
3003 statements dominating PHI skipping only statements that cannot possibly
3004 clobber REF. Decrements LIMIT for each alias disambiguation done
3005 and aborts the walk, returning NULL_TREE if it reaches zero.
3006 Returns NULL_TREE if no suitable virtual operand can be found. */
3009 get_continuation_for_phi (gimple
*phi
, ao_ref
*ref
,
3010 unsigned int &limit
, bitmap
*visited
,
3011 bool abort_on_visited
,
3012 void *(*translate
)(ao_ref
*, tree
, void *, bool *),
3015 unsigned nargs
= gimple_phi_num_args (phi
);
3017 /* Through a single-argument PHI we can simply look through. */
3019 return PHI_ARG_DEF (phi
, 0);
3021 /* For two or more arguments try to pairwise skip non-aliasing code
3022 until we hit the phi argument definition that dominates the other one. */
3023 basic_block phi_bb
= gimple_bb (phi
);
3027 /* Find a candidate for the virtual operand which definition
3028 dominates those of all others. */
3029 /* First look if any of the args themselves satisfy this. */
3030 for (i
= 0; i
< nargs
; ++i
)
3032 arg0
= PHI_ARG_DEF (phi
, i
);
3033 if (SSA_NAME_IS_DEFAULT_DEF (arg0
))
3035 basic_block def_bb
= gimple_bb (SSA_NAME_DEF_STMT (arg0
));
3036 if (def_bb
!= phi_bb
3037 && dominated_by_p (CDI_DOMINATORS
, phi_bb
, def_bb
))
3041 /* If not, look if we can reach such candidate by walking defs
3042 until we hit the immediate dominator. maybe_skip_until will
3044 basic_block dom
= get_immediate_dominator (CDI_DOMINATORS
, phi_bb
);
3046 /* Then check against the (to be) found candidate. */
3047 for (i
= 0; i
< nargs
; ++i
)
3049 arg1
= PHI_ARG_DEF (phi
, i
);
3052 else if (! maybe_skip_until (phi
, arg0
, dom
, ref
, arg1
, limit
, visited
,
3054 /* Do not translate when walking over
3058 gimple_bb (SSA_NAME_DEF_STMT (arg1
)),
3060 ? NULL
: translate
, data
))
3067 /* Based on the memory reference REF and its virtual use VUSE call
3068 WALKER for each virtual use that is equivalent to VUSE, including VUSE
3069 itself. That is, for each virtual use for which its defining statement
3070 does not clobber REF.
3072 WALKER is called with REF, the current virtual use and DATA. If
3073 WALKER returns non-NULL the walk stops and its result is returned.
3074 At the end of a non-successful walk NULL is returned.
3076 TRANSLATE if non-NULL is called with a pointer to REF, the virtual
3077 use which definition is a statement that may clobber REF and DATA.
3078 If TRANSLATE returns (void *)-1 the walk stops and NULL is returned.
3079 If TRANSLATE returns non-NULL the walk stops and its result is returned.
3080 If TRANSLATE returns NULL the walk continues and TRANSLATE is supposed
3081 to adjust REF and *DATA to make that valid.
3083 VALUEIZE if non-NULL is called with the next VUSE that is considered
3084 and return value is substituted for that. This can be used to
3085 implement optimistic value-numbering for example. Note that the
3086 VUSE argument is assumed to be valueized already.
3088 LIMIT specifies the number of alias queries we are allowed to do,
3089 the walk stops when it reaches zero and NULL is returned. LIMIT
3090 is decremented by the number of alias queries (plus adjustments
3091 done by the callbacks) upon return.
3093 TODO: Cache the vector of equivalent vuses per ref, vuse pair. */
3096 walk_non_aliased_vuses (ao_ref
*ref
, tree vuse
,
3097 void *(*walker
)(ao_ref
*, tree
, void *),
3098 void *(*translate
)(ao_ref
*, tree
, void *, bool *),
3099 tree (*valueize
)(tree
),
3100 unsigned &limit
, void *data
)
3102 bitmap visited
= NULL
;
3104 bool translated
= false;
3106 timevar_push (TV_ALIAS_STMT_WALK
);
3112 /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */
3113 res
= (*walker
) (ref
, vuse
, data
);
3115 if (res
== (void *)-1)
3120 /* Lookup succeeded. */
3121 else if (res
!= NULL
)
3126 vuse
= valueize (vuse
);
3133 def_stmt
= SSA_NAME_DEF_STMT (vuse
);
3134 if (gimple_nop_p (def_stmt
))
3136 else if (gimple_code (def_stmt
) == GIMPLE_PHI
)
3137 vuse
= get_continuation_for_phi (def_stmt
, ref
, limit
,
3138 &visited
, translated
, translate
, data
);
3141 if ((int)limit
<= 0)
3146 if (stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
3150 bool disambiguate_only
= false;
3151 res
= (*translate
) (ref
, vuse
, data
, &disambiguate_only
);
3152 /* Failed lookup and translation. */
3153 if (res
== (void *)-1)
3158 /* Lookup succeeded. */
3159 else if (res
!= NULL
)
3161 /* Translation succeeded, continue walking. */
3162 translated
= translated
|| !disambiguate_only
;
3164 vuse
= gimple_vuse (def_stmt
);
3170 BITMAP_FREE (visited
);
3172 timevar_pop (TV_ALIAS_STMT_WALK
);
3178 /* Based on the memory reference REF call WALKER for each vdef which
3179 defining statement may clobber REF, starting with VDEF. If REF
3180 is NULL_TREE, each defining statement is visited.
3182 WALKER is called with REF, the current vdef and DATA. If WALKER
3183 returns true the walk is stopped, otherwise it continues.
3185 If function entry is reached, FUNCTION_ENTRY_REACHED is set to true.
3186 The pointer may be NULL and then we do not track this information.
3188 At PHI nodes walk_aliased_vdefs forks into one walk for reach
3189 PHI argument (but only one walk continues on merge points), the
3190 return value is true if any of the walks was successful.
3192 The function returns the number of statements walked or -1 if
3193 LIMIT stmts were walked and the walk was aborted at this point.
3194 If LIMIT is zero the walk is not aborted. */
3197 walk_aliased_vdefs_1 (ao_ref
*ref
, tree vdef
,
3198 bool (*walker
)(ao_ref
*, tree
, void *), void *data
,
3199 bitmap
*visited
, unsigned int cnt
,
3200 bool *function_entry_reached
, unsigned limit
)
3204 gimple
*def_stmt
= SSA_NAME_DEF_STMT (vdef
);
3207 && !bitmap_set_bit (*visited
, SSA_NAME_VERSION (vdef
)))
3210 if (gimple_nop_p (def_stmt
))
3212 if (function_entry_reached
)
3213 *function_entry_reached
= true;
3216 else if (gimple_code (def_stmt
) == GIMPLE_PHI
)
3220 *visited
= BITMAP_ALLOC (NULL
);
3221 for (i
= 0; i
< gimple_phi_num_args (def_stmt
); ++i
)
3223 int res
= walk_aliased_vdefs_1 (ref
,
3224 gimple_phi_arg_def (def_stmt
, i
),
3225 walker
, data
, visited
, cnt
,
3226 function_entry_reached
, limit
);
3234 /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */
3239 || stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
3240 && (*walker
) (ref
, vdef
, data
))
3243 vdef
= gimple_vuse (def_stmt
);
3249 walk_aliased_vdefs (ao_ref
*ref
, tree vdef
,
3250 bool (*walker
)(ao_ref
*, tree
, void *), void *data
,
3252 bool *function_entry_reached
, unsigned int limit
)
3254 bitmap local_visited
= NULL
;
3257 timevar_push (TV_ALIAS_STMT_WALK
);
3259 if (function_entry_reached
)
3260 *function_entry_reached
= false;
3262 ret
= walk_aliased_vdefs_1 (ref
, vdef
, walker
, data
,
3263 visited
? visited
: &local_visited
, 0,
3264 function_entry_reached
, limit
);
3266 BITMAP_FREE (local_visited
);
3268 timevar_pop (TV_ALIAS_STMT_WALK
);