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 ++alias_stats
.nonoverlapping_component_refs_p_may_alias
;
1357 /* Different fields of the same record type cannot overlap.
1358 ??? Bitfields can overlap at RTL level so punt on them. */
1359 if (DECL_BIT_FIELD (fieldx
) && DECL_BIT_FIELD (fieldy
))
1361 ++alias_stats
.nonoverlapping_component_refs_p_may_alias
;
1364 ++alias_stats
.nonoverlapping_component_refs_p_no_alias
;
1368 if (TYPE_UID (typex
) < TYPE_UID (typey
))
1371 if (i
== fieldsx
.length ())
1377 if (j
== fieldsy
.length ())
1383 ++alias_stats
.nonoverlapping_component_refs_p_may_alias
;
1388 /* Return true if two memory references based on the variables BASE1
1389 and BASE2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and
1390 [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. REF1 and REF2
1391 if non-NULL are the complete memory reference trees. */
1394 decl_refs_may_alias_p (tree ref1
, tree base1
,
1395 poly_int64 offset1
, poly_int64 max_size1
,
1396 tree ref2
, tree base2
,
1397 poly_int64 offset2
, poly_int64 max_size2
)
1399 gcc_checking_assert (DECL_P (base1
) && DECL_P (base2
));
1401 /* If both references are based on different variables, they cannot alias. */
1402 if (compare_base_decls (base1
, base2
) == 0)
1405 /* If both references are based on the same variable, they cannot alias if
1406 the accesses do not overlap. */
1407 if (!ranges_maybe_overlap_p (offset1
, max_size1
, offset2
, max_size2
))
1410 /* For components with variable position, the above test isn't sufficient,
1411 so we disambiguate component references manually. */
1413 && handled_component_p (ref1
) && handled_component_p (ref2
)
1414 && nonoverlapping_component_refs_of_decl_p (ref1
, ref2
))
1420 /* Return true if an indirect reference based on *PTR1 constrained
1421 to [OFFSET1, OFFSET1 + MAX_SIZE1) may alias a variable based on BASE2
1422 constrained to [OFFSET2, OFFSET2 + MAX_SIZE2). *PTR1 and BASE2 have
1423 the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1
1424 in which case they are computed on-demand. REF1 and REF2
1425 if non-NULL are the complete memory reference trees. */
1428 indirect_ref_may_alias_decl_p (tree ref1 ATTRIBUTE_UNUSED
, tree base1
,
1429 poly_int64 offset1
, poly_int64 max_size1
,
1430 alias_set_type ref1_alias_set
,
1431 alias_set_type base1_alias_set
,
1432 tree ref2 ATTRIBUTE_UNUSED
, tree base2
,
1433 poly_int64 offset2
, poly_int64 max_size2
,
1434 alias_set_type ref2_alias_set
,
1435 alias_set_type base2_alias_set
, bool tbaa_p
)
1438 tree ptrtype1
, dbase2
;
1440 gcc_checking_assert ((TREE_CODE (base1
) == MEM_REF
1441 || TREE_CODE (base1
) == TARGET_MEM_REF
)
1444 ptr1
= TREE_OPERAND (base1
, 0);
1445 poly_offset_int moff
= mem_ref_offset (base1
) << LOG2_BITS_PER_UNIT
;
1447 /* If only one reference is based on a variable, they cannot alias if
1448 the pointer access is beyond the extent of the variable access.
1449 (the pointer base cannot validly point to an offset less than zero
1451 ??? IVOPTs creates bases that do not honor this restriction,
1452 so do not apply this optimization for TARGET_MEM_REFs. */
1453 if (TREE_CODE (base1
) != TARGET_MEM_REF
1454 && !ranges_maybe_overlap_p (offset1
+ moff
, -1, offset2
, max_size2
))
1456 /* They also cannot alias if the pointer may not point to the decl. */
1457 if (!ptr_deref_may_alias_decl_p (ptr1
, base2
))
1460 /* Disambiguations that rely on strict aliasing rules follow. */
1461 if (!flag_strict_aliasing
|| !tbaa_p
)
1464 ptrtype1
= TREE_TYPE (TREE_OPERAND (base1
, 1));
1466 /* If the alias set for a pointer access is zero all bets are off. */
1467 if (base1_alias_set
== 0)
1470 /* When we are trying to disambiguate an access with a pointer dereference
1471 as base versus one with a decl as base we can use both the size
1472 of the decl and its dynamic type for extra disambiguation.
1473 ??? We do not know anything about the dynamic type of the decl
1474 other than that its alias-set contains base2_alias_set as a subset
1475 which does not help us here. */
1476 /* As we know nothing useful about the dynamic type of the decl just
1477 use the usual conflict check rather than a subset test.
1478 ??? We could introduce -fvery-strict-aliasing when the language
1479 does not allow decls to have a dynamic type that differs from their
1480 static type. Then we can check
1481 !alias_set_subset_of (base1_alias_set, base2_alias_set) instead. */
1482 if (base1_alias_set
!= base2_alias_set
1483 && !alias_sets_conflict_p (base1_alias_set
, base2_alias_set
))
1485 /* If the size of the access relevant for TBAA through the pointer
1486 is bigger than the size of the decl we can't possibly access the
1487 decl via that pointer. */
1488 if (/* ??? This in turn may run afoul when a decl of type T which is
1489 a member of union type U is accessed through a pointer to
1490 type U and sizeof T is smaller than sizeof U. */
1491 TREE_CODE (TREE_TYPE (ptrtype1
)) != UNION_TYPE
1492 && TREE_CODE (TREE_TYPE (ptrtype1
)) != QUAL_UNION_TYPE
1493 && compare_sizes (DECL_SIZE (base2
),
1494 TYPE_SIZE (TREE_TYPE (ptrtype1
))) < 0)
1500 /* If the decl is accessed via a MEM_REF, reconstruct the base
1501 we can use for TBAA and an appropriately adjusted offset. */
1503 while (handled_component_p (dbase2
))
1504 dbase2
= TREE_OPERAND (dbase2
, 0);
1505 poly_int64 doffset1
= offset1
;
1506 poly_offset_int doffset2
= offset2
;
1507 if (TREE_CODE (dbase2
) == MEM_REF
1508 || TREE_CODE (dbase2
) == TARGET_MEM_REF
)
1510 doffset2
-= mem_ref_offset (dbase2
) << LOG2_BITS_PER_UNIT
;
1511 tree ptrtype2
= TREE_TYPE (TREE_OPERAND (dbase2
, 1));
1512 /* If second reference is view-converted, give up now. */
1513 if (same_type_for_tbaa (TREE_TYPE (dbase2
), TREE_TYPE (ptrtype2
)) != 1)
1517 /* If first reference is view-converted, give up now. */
1518 if (same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (ptrtype1
)) != 1)
1521 /* If both references are through the same type, they do not alias
1522 if the accesses do not overlap. This does extra disambiguation
1523 for mixed/pointer accesses but requires strict aliasing.
1524 For MEM_REFs we require that the component-ref offset we computed
1525 is relative to the start of the type which we ensure by
1526 comparing rvalue and access type and disregarding the constant
1529 But avoid treating variable length arrays as "objects", instead assume they
1530 can overlap by an exact multiple of their element size.
1531 See gcc.dg/torture/alias-2.c. */
1532 if (((TREE_CODE (base1
) != TARGET_MEM_REF
1533 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1534 && (TREE_CODE (dbase2
) != TARGET_MEM_REF
1535 || (!TMR_INDEX (dbase2
) && !TMR_INDEX2 (dbase2
))))
1536 && same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (dbase2
)) == 1
1537 && (TREE_CODE (TREE_TYPE (base1
)) != ARRAY_TYPE
1538 || (TYPE_SIZE (TREE_TYPE (base1
))
1539 && TREE_CODE (TYPE_SIZE (TREE_TYPE (base1
))) == INTEGER_CST
)))
1540 return ranges_maybe_overlap_p (doffset1
, max_size1
, doffset2
, max_size2
);
1543 && nonoverlapping_component_refs_p (ref1
, ref2
))
1546 /* Do access-path based disambiguation. */
1548 && (handled_component_p (ref1
) || handled_component_p (ref2
)))
1549 return aliasing_component_refs_p (ref1
,
1550 ref1_alias_set
, base1_alias_set
,
1553 ref2_alias_set
, base2_alias_set
,
1554 offset2
, max_size2
);
1559 /* Return true if two indirect references based on *PTR1
1560 and *PTR2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and
1561 [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. *PTR1 and *PTR2 have
1562 the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1
1563 in which case they are computed on-demand. REF1 and REF2
1564 if non-NULL are the complete memory reference trees. */
1567 indirect_refs_may_alias_p (tree ref1 ATTRIBUTE_UNUSED
, tree base1
,
1568 poly_int64 offset1
, poly_int64 max_size1
,
1569 alias_set_type ref1_alias_set
,
1570 alias_set_type base1_alias_set
,
1571 tree ref2 ATTRIBUTE_UNUSED
, tree base2
,
1572 poly_int64 offset2
, poly_int64 max_size2
,
1573 alias_set_type ref2_alias_set
,
1574 alias_set_type base2_alias_set
, bool tbaa_p
)
1578 tree ptrtype1
, ptrtype2
;
1580 gcc_checking_assert ((TREE_CODE (base1
) == MEM_REF
1581 || TREE_CODE (base1
) == TARGET_MEM_REF
)
1582 && (TREE_CODE (base2
) == MEM_REF
1583 || TREE_CODE (base2
) == TARGET_MEM_REF
));
1585 ptr1
= TREE_OPERAND (base1
, 0);
1586 ptr2
= TREE_OPERAND (base2
, 0);
1588 /* If both bases are based on pointers they cannot alias if they may not
1589 point to the same memory object or if they point to the same object
1590 and the accesses do not overlap. */
1591 if ((!cfun
|| gimple_in_ssa_p (cfun
))
1592 && operand_equal_p (ptr1
, ptr2
, 0)
1593 && (((TREE_CODE (base1
) != TARGET_MEM_REF
1594 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1595 && (TREE_CODE (base2
) != TARGET_MEM_REF
1596 || (!TMR_INDEX (base2
) && !TMR_INDEX2 (base2
))))
1597 || (TREE_CODE (base1
) == TARGET_MEM_REF
1598 && TREE_CODE (base2
) == TARGET_MEM_REF
1599 && (TMR_STEP (base1
) == TMR_STEP (base2
)
1600 || (TMR_STEP (base1
) && TMR_STEP (base2
)
1601 && operand_equal_p (TMR_STEP (base1
),
1602 TMR_STEP (base2
), 0)))
1603 && (TMR_INDEX (base1
) == TMR_INDEX (base2
)
1604 || (TMR_INDEX (base1
) && TMR_INDEX (base2
)
1605 && operand_equal_p (TMR_INDEX (base1
),
1606 TMR_INDEX (base2
), 0)))
1607 && (TMR_INDEX2 (base1
) == TMR_INDEX2 (base2
)
1608 || (TMR_INDEX2 (base1
) && TMR_INDEX2 (base2
)
1609 && operand_equal_p (TMR_INDEX2 (base1
),
1610 TMR_INDEX2 (base2
), 0))))))
1612 poly_offset_int moff1
= mem_ref_offset (base1
) << LOG2_BITS_PER_UNIT
;
1613 poly_offset_int moff2
= mem_ref_offset (base2
) << LOG2_BITS_PER_UNIT
;
1614 return ranges_maybe_overlap_p (offset1
+ moff1
, max_size1
,
1615 offset2
+ moff2
, max_size2
);
1617 if (!ptr_derefs_may_alias_p (ptr1
, ptr2
))
1620 /* Disambiguations that rely on strict aliasing rules follow. */
1621 if (!flag_strict_aliasing
|| !tbaa_p
)
1624 ptrtype1
= TREE_TYPE (TREE_OPERAND (base1
, 1));
1625 ptrtype2
= TREE_TYPE (TREE_OPERAND (base2
, 1));
1627 /* If the alias set for a pointer access is zero all bets are off. */
1628 if (base1_alias_set
== 0
1629 || base2_alias_set
== 0)
1632 /* Do type-based disambiguation. */
1633 if (base1_alias_set
!= base2_alias_set
1634 && !alias_sets_conflict_p (base1_alias_set
, base2_alias_set
))
1637 /* If either reference is view-converted, give up now. */
1638 if (same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (ptrtype1
)) != 1
1639 || same_type_for_tbaa (TREE_TYPE (base2
), TREE_TYPE (ptrtype2
)) != 1)
1642 /* If both references are through the same type, they do not alias
1643 if the accesses do not overlap. This does extra disambiguation
1644 for mixed/pointer accesses but requires strict aliasing. */
1645 if ((TREE_CODE (base1
) != TARGET_MEM_REF
1646 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1647 && (TREE_CODE (base2
) != TARGET_MEM_REF
1648 || (!TMR_INDEX (base2
) && !TMR_INDEX2 (base2
)))
1649 && same_type_for_tbaa (TREE_TYPE (ptrtype1
),
1650 TREE_TYPE (ptrtype2
)) == 1
1651 /* But avoid treating arrays as "objects", instead assume they
1652 can overlap by an exact multiple of their element size.
1653 See gcc.dg/torture/alias-2.c. */
1654 && TREE_CODE (TREE_TYPE (ptrtype1
)) != ARRAY_TYPE
)
1655 return ranges_maybe_overlap_p (offset1
, max_size1
, offset2
, max_size2
);
1658 && nonoverlapping_component_refs_p (ref1
, ref2
))
1661 /* Do access-path based disambiguation. */
1663 && (handled_component_p (ref1
) || handled_component_p (ref2
)))
1664 return aliasing_component_refs_p (ref1
,
1665 ref1_alias_set
, base1_alias_set
,
1668 ref2_alias_set
, base2_alias_set
,
1669 offset2
, max_size2
);
1674 /* Return true, if the two memory references REF1 and REF2 may alias. */
1677 refs_may_alias_p_2 (ao_ref
*ref1
, ao_ref
*ref2
, bool tbaa_p
)
1680 poly_int64 offset1
= 0, offset2
= 0;
1681 poly_int64 max_size1
= -1, max_size2
= -1;
1682 bool var1_p
, var2_p
, ind1_p
, ind2_p
;
1684 gcc_checking_assert ((!ref1
->ref
1685 || TREE_CODE (ref1
->ref
) == SSA_NAME
1686 || DECL_P (ref1
->ref
)
1687 || TREE_CODE (ref1
->ref
) == STRING_CST
1688 || handled_component_p (ref1
->ref
)
1689 || TREE_CODE (ref1
->ref
) == MEM_REF
1690 || TREE_CODE (ref1
->ref
) == TARGET_MEM_REF
)
1692 || TREE_CODE (ref2
->ref
) == SSA_NAME
1693 || DECL_P (ref2
->ref
)
1694 || TREE_CODE (ref2
->ref
) == STRING_CST
1695 || handled_component_p (ref2
->ref
)
1696 || TREE_CODE (ref2
->ref
) == MEM_REF
1697 || TREE_CODE (ref2
->ref
) == TARGET_MEM_REF
));
1699 /* Decompose the references into their base objects and the access. */
1700 base1
= ao_ref_base (ref1
);
1701 offset1
= ref1
->offset
;
1702 max_size1
= ref1
->max_size
;
1703 base2
= ao_ref_base (ref2
);
1704 offset2
= ref2
->offset
;
1705 max_size2
= ref2
->max_size
;
1707 /* We can end up with registers or constants as bases for example from
1708 *D.1663_44 = VIEW_CONVERT_EXPR<struct DB_LSN>(__tmp$B0F64_59);
1709 which is seen as a struct copy. */
1710 if (TREE_CODE (base1
) == SSA_NAME
1711 || TREE_CODE (base1
) == CONST_DECL
1712 || TREE_CODE (base1
) == CONSTRUCTOR
1713 || TREE_CODE (base1
) == ADDR_EXPR
1714 || CONSTANT_CLASS_P (base1
)
1715 || TREE_CODE (base2
) == SSA_NAME
1716 || TREE_CODE (base2
) == CONST_DECL
1717 || TREE_CODE (base2
) == CONSTRUCTOR
1718 || TREE_CODE (base2
) == ADDR_EXPR
1719 || CONSTANT_CLASS_P (base2
))
1722 /* We can end up referring to code via function and label decls.
1723 As we likely do not properly track code aliases conservatively
1725 if (TREE_CODE (base1
) == FUNCTION_DECL
1726 || TREE_CODE (base1
) == LABEL_DECL
1727 || TREE_CODE (base2
) == FUNCTION_DECL
1728 || TREE_CODE (base2
) == LABEL_DECL
)
1731 /* Two volatile accesses always conflict. */
1732 if (ref1
->volatile_p
1733 && ref2
->volatile_p
)
1736 /* Defer to simple offset based disambiguation if we have
1737 references based on two decls. Do this before defering to
1738 TBAA to handle must-alias cases in conformance with the
1739 GCC extension of allowing type-punning through unions. */
1740 var1_p
= DECL_P (base1
);
1741 var2_p
= DECL_P (base2
);
1742 if (var1_p
&& var2_p
)
1743 return decl_refs_may_alias_p (ref1
->ref
, base1
, offset1
, max_size1
,
1744 ref2
->ref
, base2
, offset2
, max_size2
);
1746 /* Handle restrict based accesses.
1747 ??? ao_ref_base strips inner MEM_REF [&decl], recover from that
1749 tree rbase1
= base1
;
1750 tree rbase2
= base2
;
1755 while (handled_component_p (rbase1
))
1756 rbase1
= TREE_OPERAND (rbase1
, 0);
1762 while (handled_component_p (rbase2
))
1763 rbase2
= TREE_OPERAND (rbase2
, 0);
1765 if (rbase1
&& rbase2
1766 && (TREE_CODE (base1
) == MEM_REF
|| TREE_CODE (base1
) == TARGET_MEM_REF
)
1767 && (TREE_CODE (base2
) == MEM_REF
|| TREE_CODE (base2
) == TARGET_MEM_REF
)
1768 /* If the accesses are in the same restrict clique... */
1769 && MR_DEPENDENCE_CLIQUE (base1
) == MR_DEPENDENCE_CLIQUE (base2
)
1770 /* But based on different pointers they do not alias. */
1771 && MR_DEPENDENCE_BASE (base1
) != MR_DEPENDENCE_BASE (base2
))
1774 ind1_p
= (TREE_CODE (base1
) == MEM_REF
1775 || TREE_CODE (base1
) == TARGET_MEM_REF
);
1776 ind2_p
= (TREE_CODE (base2
) == MEM_REF
1777 || TREE_CODE (base2
) == TARGET_MEM_REF
);
1779 /* Canonicalize the pointer-vs-decl case. */
1780 if (ind1_p
&& var2_p
)
1782 std::swap (offset1
, offset2
);
1783 std::swap (max_size1
, max_size2
);
1784 std::swap (base1
, base2
);
1785 std::swap (ref1
, ref2
);
1792 /* First defer to TBAA if possible. */
1794 && flag_strict_aliasing
1795 && !alias_sets_conflict_p (ao_ref_alias_set (ref1
),
1796 ao_ref_alias_set (ref2
)))
1799 /* If the reference is based on a pointer that points to memory
1800 that may not be written to then the other reference cannot possibly
1802 if ((TREE_CODE (TREE_OPERAND (base2
, 0)) == SSA_NAME
1803 && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base2
, 0)))
1805 && TREE_CODE (TREE_OPERAND (base1
, 0)) == SSA_NAME
1806 && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base1
, 0))))
1809 /* Dispatch to the pointer-vs-decl or pointer-vs-pointer disambiguators. */
1810 if (var1_p
&& ind2_p
)
1811 return indirect_ref_may_alias_decl_p (ref2
->ref
, base2
,
1813 ao_ref_alias_set (ref2
),
1814 ao_ref_base_alias_set (ref2
),
1817 ao_ref_alias_set (ref1
),
1818 ao_ref_base_alias_set (ref1
),
1820 else if (ind1_p
&& ind2_p
)
1821 return indirect_refs_may_alias_p (ref1
->ref
, base1
,
1823 ao_ref_alias_set (ref1
),
1824 ao_ref_base_alias_set (ref1
),
1827 ao_ref_alias_set (ref2
),
1828 ao_ref_base_alias_set (ref2
),
1834 /* Return true, if the two memory references REF1 and REF2 may alias
1835 and update statistics. */
1838 refs_may_alias_p_1 (ao_ref
*ref1
, ao_ref
*ref2
, bool tbaa_p
)
1840 bool res
= refs_may_alias_p_2 (ref1
, ref2
, tbaa_p
);
1842 ++alias_stats
.refs_may_alias_p_may_alias
;
1844 ++alias_stats
.refs_may_alias_p_no_alias
;
1849 refs_may_alias_p (tree ref1
, ao_ref
*ref2
, bool tbaa_p
)
1852 ao_ref_init (&r1
, ref1
);
1853 return refs_may_alias_p_1 (&r1
, ref2
, tbaa_p
);
1857 refs_may_alias_p (tree ref1
, tree ref2
, bool tbaa_p
)
1860 ao_ref_init (&r1
, ref1
);
1861 ao_ref_init (&r2
, ref2
);
1862 return refs_may_alias_p_1 (&r1
, &r2
, tbaa_p
);
1865 /* Returns true if there is a anti-dependence for the STORE that
1866 executes after the LOAD. */
1869 refs_anti_dependent_p (tree load
, tree store
)
1872 ao_ref_init (&r1
, load
);
1873 ao_ref_init (&r2
, store
);
1874 return refs_may_alias_p_1 (&r1
, &r2
, false);
1877 /* Returns true if there is a output dependence for the stores
1878 STORE1 and STORE2. */
1881 refs_output_dependent_p (tree store1
, tree store2
)
1884 ao_ref_init (&r1
, store1
);
1885 ao_ref_init (&r2
, store2
);
1886 return refs_may_alias_p_1 (&r1
, &r2
, false);
1889 /* If the call CALL may use the memory reference REF return true,
1890 otherwise return false. */
1893 ref_maybe_used_by_call_p_1 (gcall
*call
, ao_ref
*ref
, bool tbaa_p
)
1897 int flags
= gimple_call_flags (call
);
1899 /* Const functions without a static chain do not implicitly use memory. */
1900 if (!gimple_call_chain (call
)
1901 && (flags
& (ECF_CONST
|ECF_NOVOPS
)))
1904 base
= ao_ref_base (ref
);
1908 /* A call that is not without side-effects might involve volatile
1909 accesses and thus conflicts with all other volatile accesses. */
1910 if (ref
->volatile_p
)
1913 /* If the reference is based on a decl that is not aliased the call
1914 cannot possibly use it. */
1916 && !may_be_aliased (base
)
1917 /* But local statics can be used through recursion. */
1918 && !is_global_var (base
))
1921 callee
= gimple_call_fndecl (call
);
1923 /* Handle those builtin functions explicitly that do not act as
1924 escape points. See tree-ssa-structalias.c:find_func_aliases
1925 for the list of builtins we might need to handle here. */
1926 if (callee
!= NULL_TREE
1927 && gimple_call_builtin_p (call
, BUILT_IN_NORMAL
))
1928 switch (DECL_FUNCTION_CODE (callee
))
1930 /* All the following functions read memory pointed to by
1931 their second argument. strcat/strncat additionally
1932 reads memory pointed to by the first argument. */
1933 case BUILT_IN_STRCAT
:
1934 case BUILT_IN_STRNCAT
:
1937 ao_ref_init_from_ptr_and_size (&dref
,
1938 gimple_call_arg (call
, 0),
1940 if (refs_may_alias_p_1 (&dref
, ref
, false))
1944 case BUILT_IN_STRCPY
:
1945 case BUILT_IN_STRNCPY
:
1946 case BUILT_IN_MEMCPY
:
1947 case BUILT_IN_MEMMOVE
:
1948 case BUILT_IN_MEMPCPY
:
1949 case BUILT_IN_STPCPY
:
1950 case BUILT_IN_STPNCPY
:
1951 case BUILT_IN_TM_MEMCPY
:
1952 case BUILT_IN_TM_MEMMOVE
:
1955 tree size
= NULL_TREE
;
1956 if (gimple_call_num_args (call
) == 3)
1957 size
= gimple_call_arg (call
, 2);
1958 ao_ref_init_from_ptr_and_size (&dref
,
1959 gimple_call_arg (call
, 1),
1961 return refs_may_alias_p_1 (&dref
, ref
, false);
1963 case BUILT_IN_STRCAT_CHK
:
1964 case BUILT_IN_STRNCAT_CHK
:
1967 ao_ref_init_from_ptr_and_size (&dref
,
1968 gimple_call_arg (call
, 0),
1970 if (refs_may_alias_p_1 (&dref
, ref
, false))
1974 case BUILT_IN_STRCPY_CHK
:
1975 case BUILT_IN_STRNCPY_CHK
:
1976 case BUILT_IN_MEMCPY_CHK
:
1977 case BUILT_IN_MEMMOVE_CHK
:
1978 case BUILT_IN_MEMPCPY_CHK
:
1979 case BUILT_IN_STPCPY_CHK
:
1980 case BUILT_IN_STPNCPY_CHK
:
1983 tree size
= NULL_TREE
;
1984 if (gimple_call_num_args (call
) == 4)
1985 size
= gimple_call_arg (call
, 2);
1986 ao_ref_init_from_ptr_and_size (&dref
,
1987 gimple_call_arg (call
, 1),
1989 return refs_may_alias_p_1 (&dref
, ref
, false);
1991 case BUILT_IN_BCOPY
:
1994 tree size
= gimple_call_arg (call
, 2);
1995 ao_ref_init_from_ptr_and_size (&dref
,
1996 gimple_call_arg (call
, 0),
1998 return refs_may_alias_p_1 (&dref
, ref
, false);
2001 /* The following functions read memory pointed to by their
2003 CASE_BUILT_IN_TM_LOAD (1):
2004 CASE_BUILT_IN_TM_LOAD (2):
2005 CASE_BUILT_IN_TM_LOAD (4):
2006 CASE_BUILT_IN_TM_LOAD (8):
2007 CASE_BUILT_IN_TM_LOAD (FLOAT
):
2008 CASE_BUILT_IN_TM_LOAD (DOUBLE
):
2009 CASE_BUILT_IN_TM_LOAD (LDOUBLE
):
2010 CASE_BUILT_IN_TM_LOAD (M64
):
2011 CASE_BUILT_IN_TM_LOAD (M128
):
2012 CASE_BUILT_IN_TM_LOAD (M256
):
2013 case BUILT_IN_TM_LOG
:
2014 case BUILT_IN_TM_LOG_1
:
2015 case BUILT_IN_TM_LOG_2
:
2016 case BUILT_IN_TM_LOG_4
:
2017 case BUILT_IN_TM_LOG_8
:
2018 case BUILT_IN_TM_LOG_FLOAT
:
2019 case BUILT_IN_TM_LOG_DOUBLE
:
2020 case BUILT_IN_TM_LOG_LDOUBLE
:
2021 case BUILT_IN_TM_LOG_M64
:
2022 case BUILT_IN_TM_LOG_M128
:
2023 case BUILT_IN_TM_LOG_M256
:
2024 return ptr_deref_may_alias_ref_p_1 (gimple_call_arg (call
, 0), ref
);
2026 /* These read memory pointed to by the first argument. */
2027 case BUILT_IN_STRDUP
:
2028 case BUILT_IN_STRNDUP
:
2029 case BUILT_IN_REALLOC
:
2032 tree size
= NULL_TREE
;
2033 if (gimple_call_num_args (call
) == 2)
2034 size
= gimple_call_arg (call
, 1);
2035 ao_ref_init_from_ptr_and_size (&dref
,
2036 gimple_call_arg (call
, 0),
2038 return refs_may_alias_p_1 (&dref
, ref
, false);
2040 /* These read memory pointed to by the first argument. */
2041 case BUILT_IN_INDEX
:
2042 case BUILT_IN_STRCHR
:
2043 case BUILT_IN_STRRCHR
:
2046 ao_ref_init_from_ptr_and_size (&dref
,
2047 gimple_call_arg (call
, 0),
2049 return refs_may_alias_p_1 (&dref
, ref
, false);
2051 /* These read memory pointed to by the first argument with size
2052 in the third argument. */
2053 case BUILT_IN_MEMCHR
:
2056 ao_ref_init_from_ptr_and_size (&dref
,
2057 gimple_call_arg (call
, 0),
2058 gimple_call_arg (call
, 2));
2059 return refs_may_alias_p_1 (&dref
, ref
, false);
2061 /* These read memory pointed to by the first and second arguments. */
2062 case BUILT_IN_STRSTR
:
2063 case BUILT_IN_STRPBRK
:
2066 ao_ref_init_from_ptr_and_size (&dref
,
2067 gimple_call_arg (call
, 0),
2069 if (refs_may_alias_p_1 (&dref
, ref
, false))
2071 ao_ref_init_from_ptr_and_size (&dref
,
2072 gimple_call_arg (call
, 1),
2074 return refs_may_alias_p_1 (&dref
, ref
, false);
2077 /* The following builtins do not read from memory. */
2079 case BUILT_IN_MALLOC
:
2080 case BUILT_IN_POSIX_MEMALIGN
:
2081 case BUILT_IN_ALIGNED_ALLOC
:
2082 case BUILT_IN_CALLOC
:
2083 CASE_BUILT_IN_ALLOCA
:
2084 case BUILT_IN_STACK_SAVE
:
2085 case BUILT_IN_STACK_RESTORE
:
2086 case BUILT_IN_MEMSET
:
2087 case BUILT_IN_TM_MEMSET
:
2088 case BUILT_IN_MEMSET_CHK
:
2089 case BUILT_IN_FREXP
:
2090 case BUILT_IN_FREXPF
:
2091 case BUILT_IN_FREXPL
:
2092 case BUILT_IN_GAMMA_R
:
2093 case BUILT_IN_GAMMAF_R
:
2094 case BUILT_IN_GAMMAL_R
:
2095 case BUILT_IN_LGAMMA_R
:
2096 case BUILT_IN_LGAMMAF_R
:
2097 case BUILT_IN_LGAMMAL_R
:
2099 case BUILT_IN_MODFF
:
2100 case BUILT_IN_MODFL
:
2101 case BUILT_IN_REMQUO
:
2102 case BUILT_IN_REMQUOF
:
2103 case BUILT_IN_REMQUOL
:
2104 case BUILT_IN_SINCOS
:
2105 case BUILT_IN_SINCOSF
:
2106 case BUILT_IN_SINCOSL
:
2107 case BUILT_IN_ASSUME_ALIGNED
:
2108 case BUILT_IN_VA_END
:
2110 /* __sync_* builtins and some OpenMP builtins act as threading
2112 #undef DEF_SYNC_BUILTIN
2113 #define DEF_SYNC_BUILTIN(ENUM, NAME, TYPE, ATTRS) case ENUM:
2114 #include "sync-builtins.def"
2115 #undef DEF_SYNC_BUILTIN
2116 case BUILT_IN_GOMP_ATOMIC_START
:
2117 case BUILT_IN_GOMP_ATOMIC_END
:
2118 case BUILT_IN_GOMP_BARRIER
:
2119 case BUILT_IN_GOMP_BARRIER_CANCEL
:
2120 case BUILT_IN_GOMP_TASKWAIT
:
2121 case BUILT_IN_GOMP_TASKGROUP_END
:
2122 case BUILT_IN_GOMP_CRITICAL_START
:
2123 case BUILT_IN_GOMP_CRITICAL_END
:
2124 case BUILT_IN_GOMP_CRITICAL_NAME_START
:
2125 case BUILT_IN_GOMP_CRITICAL_NAME_END
:
2126 case BUILT_IN_GOMP_LOOP_END
:
2127 case BUILT_IN_GOMP_LOOP_END_CANCEL
:
2128 case BUILT_IN_GOMP_ORDERED_START
:
2129 case BUILT_IN_GOMP_ORDERED_END
:
2130 case BUILT_IN_GOMP_SECTIONS_END
:
2131 case BUILT_IN_GOMP_SECTIONS_END_CANCEL
:
2132 case BUILT_IN_GOMP_SINGLE_COPY_START
:
2133 case BUILT_IN_GOMP_SINGLE_COPY_END
:
2137 /* Fallthru to general call handling. */;
2140 /* Check if base is a global static variable that is not read
2142 if (callee
!= NULL_TREE
&& VAR_P (base
) && TREE_STATIC (base
))
2144 struct cgraph_node
*node
= cgraph_node::get (callee
);
2147 /* FIXME: Callee can be an OMP builtin that does not have a call graph
2148 node yet. We should enforce that there are nodes for all decls in the
2149 IL and remove this check instead. */
2151 && (not_read
= ipa_reference_get_not_read_global (node
))
2152 && bitmap_bit_p (not_read
, ipa_reference_var_uid (base
)))
2156 /* Check if the base variable is call-used. */
2159 if (pt_solution_includes (gimple_call_use_set (call
), base
))
2162 else if ((TREE_CODE (base
) == MEM_REF
2163 || TREE_CODE (base
) == TARGET_MEM_REF
)
2164 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
)
2166 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (TREE_OPERAND (base
, 0));
2170 if (pt_solutions_intersect (gimple_call_use_set (call
), &pi
->pt
))
2176 /* Inspect call arguments for passed-by-value aliases. */
2178 for (i
= 0; i
< gimple_call_num_args (call
); ++i
)
2180 tree op
= gimple_call_arg (call
, i
);
2181 int flags
= gimple_call_arg_flags (call
, i
);
2183 if (flags
& EAF_UNUSED
)
2186 if (TREE_CODE (op
) == WITH_SIZE_EXPR
)
2187 op
= TREE_OPERAND (op
, 0);
2189 if (TREE_CODE (op
) != SSA_NAME
2190 && !is_gimple_min_invariant (op
))
2193 ao_ref_init (&r
, op
);
2194 if (refs_may_alias_p_1 (&r
, ref
, tbaa_p
))
2203 ref_maybe_used_by_call_p (gcall
*call
, ao_ref
*ref
, bool tbaa_p
)
2206 res
= ref_maybe_used_by_call_p_1 (call
, ref
, tbaa_p
);
2208 ++alias_stats
.ref_maybe_used_by_call_p_may_alias
;
2210 ++alias_stats
.ref_maybe_used_by_call_p_no_alias
;
2215 /* If the statement STMT may use the memory reference REF return
2216 true, otherwise return false. */
2219 ref_maybe_used_by_stmt_p (gimple
*stmt
, ao_ref
*ref
, bool tbaa_p
)
2221 if (is_gimple_assign (stmt
))
2225 /* All memory assign statements are single. */
2226 if (!gimple_assign_single_p (stmt
))
2229 rhs
= gimple_assign_rhs1 (stmt
);
2230 if (is_gimple_reg (rhs
)
2231 || is_gimple_min_invariant (rhs
)
2232 || gimple_assign_rhs_code (stmt
) == CONSTRUCTOR
)
2235 return refs_may_alias_p (rhs
, ref
, tbaa_p
);
2237 else if (is_gimple_call (stmt
))
2238 return ref_maybe_used_by_call_p (as_a
<gcall
*> (stmt
), ref
, tbaa_p
);
2239 else if (greturn
*return_stmt
= dyn_cast
<greturn
*> (stmt
))
2241 tree retval
= gimple_return_retval (return_stmt
);
2243 && TREE_CODE (retval
) != SSA_NAME
2244 && !is_gimple_min_invariant (retval
)
2245 && refs_may_alias_p (retval
, ref
, tbaa_p
))
2247 /* If ref escapes the function then the return acts as a use. */
2248 tree base
= ao_ref_base (ref
);
2251 else if (DECL_P (base
))
2252 return is_global_var (base
);
2253 else if (TREE_CODE (base
) == MEM_REF
2254 || TREE_CODE (base
) == TARGET_MEM_REF
)
2255 return ptr_deref_may_alias_global_p (TREE_OPERAND (base
, 0));
2263 ref_maybe_used_by_stmt_p (gimple
*stmt
, tree ref
, bool tbaa_p
)
2266 ao_ref_init (&r
, ref
);
2267 return ref_maybe_used_by_stmt_p (stmt
, &r
, tbaa_p
);
2270 /* If the call in statement CALL may clobber the memory reference REF
2271 return true, otherwise return false. */
2274 call_may_clobber_ref_p_1 (gcall
*call
, ao_ref
*ref
)
2279 /* If the call is pure or const it cannot clobber anything. */
2280 if (gimple_call_flags (call
)
2281 & (ECF_PURE
|ECF_CONST
|ECF_LOOPING_CONST_OR_PURE
|ECF_NOVOPS
))
2283 if (gimple_call_internal_p (call
))
2284 switch (gimple_call_internal_fn (call
))
2286 /* Treat these internal calls like ECF_PURE for aliasing,
2287 they don't write to any memory the program should care about.
2288 They have important other side-effects, and read memory,
2289 so can't be ECF_NOVOPS. */
2290 case IFN_UBSAN_NULL
:
2291 case IFN_UBSAN_BOUNDS
:
2292 case IFN_UBSAN_VPTR
:
2293 case IFN_UBSAN_OBJECT_SIZE
:
2295 case IFN_ASAN_CHECK
:
2301 base
= ao_ref_base (ref
);
2305 if (TREE_CODE (base
) == SSA_NAME
2306 || CONSTANT_CLASS_P (base
))
2309 /* A call that is not without side-effects might involve volatile
2310 accesses and thus conflicts with all other volatile accesses. */
2311 if (ref
->volatile_p
)
2314 /* If the reference is based on a decl that is not aliased the call
2315 cannot possibly clobber it. */
2317 && !may_be_aliased (base
)
2318 /* But local non-readonly statics can be modified through recursion
2319 or the call may implement a threading barrier which we must
2320 treat as may-def. */
2321 && (TREE_READONLY (base
)
2322 || !is_global_var (base
)))
2325 /* If the reference is based on a pointer that points to memory
2326 that may not be written to then the call cannot possibly clobber it. */
2327 if ((TREE_CODE (base
) == MEM_REF
2328 || TREE_CODE (base
) == TARGET_MEM_REF
)
2329 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
2330 && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base
, 0)))
2333 callee
= gimple_call_fndecl (call
);
2335 /* Handle those builtin functions explicitly that do not act as
2336 escape points. See tree-ssa-structalias.c:find_func_aliases
2337 for the list of builtins we might need to handle here. */
2338 if (callee
!= NULL_TREE
2339 && gimple_call_builtin_p (call
, BUILT_IN_NORMAL
))
2340 switch (DECL_FUNCTION_CODE (callee
))
2342 /* All the following functions clobber memory pointed to by
2343 their first argument. */
2344 case BUILT_IN_STRCPY
:
2345 case BUILT_IN_STRNCPY
:
2346 case BUILT_IN_MEMCPY
:
2347 case BUILT_IN_MEMMOVE
:
2348 case BUILT_IN_MEMPCPY
:
2349 case BUILT_IN_STPCPY
:
2350 case BUILT_IN_STPNCPY
:
2351 case BUILT_IN_STRCAT
:
2352 case BUILT_IN_STRNCAT
:
2353 case BUILT_IN_MEMSET
:
2354 case BUILT_IN_TM_MEMSET
:
2355 CASE_BUILT_IN_TM_STORE (1):
2356 CASE_BUILT_IN_TM_STORE (2):
2357 CASE_BUILT_IN_TM_STORE (4):
2358 CASE_BUILT_IN_TM_STORE (8):
2359 CASE_BUILT_IN_TM_STORE (FLOAT
):
2360 CASE_BUILT_IN_TM_STORE (DOUBLE
):
2361 CASE_BUILT_IN_TM_STORE (LDOUBLE
):
2362 CASE_BUILT_IN_TM_STORE (M64
):
2363 CASE_BUILT_IN_TM_STORE (M128
):
2364 CASE_BUILT_IN_TM_STORE (M256
):
2365 case BUILT_IN_TM_MEMCPY
:
2366 case BUILT_IN_TM_MEMMOVE
:
2369 tree size
= NULL_TREE
;
2370 /* Don't pass in size for strncat, as the maximum size
2371 is strlen (dest) + n + 1 instead of n, resp.
2372 n + 1 at dest + strlen (dest), but strlen (dest) isn't
2374 if (gimple_call_num_args (call
) == 3
2375 && DECL_FUNCTION_CODE (callee
) != BUILT_IN_STRNCAT
)
2376 size
= gimple_call_arg (call
, 2);
2377 ao_ref_init_from_ptr_and_size (&dref
,
2378 gimple_call_arg (call
, 0),
2380 return refs_may_alias_p_1 (&dref
, ref
, false);
2382 case BUILT_IN_STRCPY_CHK
:
2383 case BUILT_IN_STRNCPY_CHK
:
2384 case BUILT_IN_MEMCPY_CHK
:
2385 case BUILT_IN_MEMMOVE_CHK
:
2386 case BUILT_IN_MEMPCPY_CHK
:
2387 case BUILT_IN_STPCPY_CHK
:
2388 case BUILT_IN_STPNCPY_CHK
:
2389 case BUILT_IN_STRCAT_CHK
:
2390 case BUILT_IN_STRNCAT_CHK
:
2391 case BUILT_IN_MEMSET_CHK
:
2394 tree size
= NULL_TREE
;
2395 /* Don't pass in size for __strncat_chk, as the maximum size
2396 is strlen (dest) + n + 1 instead of n, resp.
2397 n + 1 at dest + strlen (dest), but strlen (dest) isn't
2399 if (gimple_call_num_args (call
) == 4
2400 && DECL_FUNCTION_CODE (callee
) != BUILT_IN_STRNCAT_CHK
)
2401 size
= gimple_call_arg (call
, 2);
2402 ao_ref_init_from_ptr_and_size (&dref
,
2403 gimple_call_arg (call
, 0),
2405 return refs_may_alias_p_1 (&dref
, ref
, false);
2407 case BUILT_IN_BCOPY
:
2410 tree size
= gimple_call_arg (call
, 2);
2411 ao_ref_init_from_ptr_and_size (&dref
,
2412 gimple_call_arg (call
, 1),
2414 return refs_may_alias_p_1 (&dref
, ref
, false);
2416 /* Allocating memory does not have any side-effects apart from
2417 being the definition point for the pointer. */
2418 case BUILT_IN_MALLOC
:
2419 case BUILT_IN_ALIGNED_ALLOC
:
2420 case BUILT_IN_CALLOC
:
2421 case BUILT_IN_STRDUP
:
2422 case BUILT_IN_STRNDUP
:
2423 /* Unix98 specifies that errno is set on allocation failure. */
2425 && targetm
.ref_may_alias_errno (ref
))
2428 case BUILT_IN_STACK_SAVE
:
2429 CASE_BUILT_IN_ALLOCA
:
2430 case BUILT_IN_ASSUME_ALIGNED
:
2432 /* But posix_memalign stores a pointer into the memory pointed to
2433 by its first argument. */
2434 case BUILT_IN_POSIX_MEMALIGN
:
2436 tree ptrptr
= gimple_call_arg (call
, 0);
2438 ao_ref_init_from_ptr_and_size (&dref
, ptrptr
,
2439 TYPE_SIZE_UNIT (ptr_type_node
));
2440 return (refs_may_alias_p_1 (&dref
, ref
, false)
2442 && targetm
.ref_may_alias_errno (ref
)));
2444 /* Freeing memory kills the pointed-to memory. More importantly
2445 the call has to serve as a barrier for moving loads and stores
2448 case BUILT_IN_VA_END
:
2450 tree ptr
= gimple_call_arg (call
, 0);
2451 return ptr_deref_may_alias_ref_p_1 (ptr
, ref
);
2453 /* Realloc serves both as allocation point and deallocation point. */
2454 case BUILT_IN_REALLOC
:
2456 tree ptr
= gimple_call_arg (call
, 0);
2457 /* Unix98 specifies that errno is set on allocation failure. */
2458 return ((flag_errno_math
2459 && targetm
.ref_may_alias_errno (ref
))
2460 || ptr_deref_may_alias_ref_p_1 (ptr
, ref
));
2462 case BUILT_IN_GAMMA_R
:
2463 case BUILT_IN_GAMMAF_R
:
2464 case BUILT_IN_GAMMAL_R
:
2465 case BUILT_IN_LGAMMA_R
:
2466 case BUILT_IN_LGAMMAF_R
:
2467 case BUILT_IN_LGAMMAL_R
:
2469 tree out
= gimple_call_arg (call
, 1);
2470 if (ptr_deref_may_alias_ref_p_1 (out
, ref
))
2472 if (flag_errno_math
)
2476 case BUILT_IN_FREXP
:
2477 case BUILT_IN_FREXPF
:
2478 case BUILT_IN_FREXPL
:
2480 case BUILT_IN_MODFF
:
2481 case BUILT_IN_MODFL
:
2483 tree out
= gimple_call_arg (call
, 1);
2484 return ptr_deref_may_alias_ref_p_1 (out
, ref
);
2486 case BUILT_IN_REMQUO
:
2487 case BUILT_IN_REMQUOF
:
2488 case BUILT_IN_REMQUOL
:
2490 tree out
= gimple_call_arg (call
, 2);
2491 if (ptr_deref_may_alias_ref_p_1 (out
, ref
))
2493 if (flag_errno_math
)
2497 case BUILT_IN_SINCOS
:
2498 case BUILT_IN_SINCOSF
:
2499 case BUILT_IN_SINCOSL
:
2501 tree sin
= gimple_call_arg (call
, 1);
2502 tree cos
= gimple_call_arg (call
, 2);
2503 return (ptr_deref_may_alias_ref_p_1 (sin
, ref
)
2504 || ptr_deref_may_alias_ref_p_1 (cos
, ref
));
2506 /* __sync_* builtins and some OpenMP builtins act as threading
2508 #undef DEF_SYNC_BUILTIN
2509 #define DEF_SYNC_BUILTIN(ENUM, NAME, TYPE, ATTRS) case ENUM:
2510 #include "sync-builtins.def"
2511 #undef DEF_SYNC_BUILTIN
2512 case BUILT_IN_GOMP_ATOMIC_START
:
2513 case BUILT_IN_GOMP_ATOMIC_END
:
2514 case BUILT_IN_GOMP_BARRIER
:
2515 case BUILT_IN_GOMP_BARRIER_CANCEL
:
2516 case BUILT_IN_GOMP_TASKWAIT
:
2517 case BUILT_IN_GOMP_TASKGROUP_END
:
2518 case BUILT_IN_GOMP_CRITICAL_START
:
2519 case BUILT_IN_GOMP_CRITICAL_END
:
2520 case BUILT_IN_GOMP_CRITICAL_NAME_START
:
2521 case BUILT_IN_GOMP_CRITICAL_NAME_END
:
2522 case BUILT_IN_GOMP_LOOP_END
:
2523 case BUILT_IN_GOMP_LOOP_END_CANCEL
:
2524 case BUILT_IN_GOMP_ORDERED_START
:
2525 case BUILT_IN_GOMP_ORDERED_END
:
2526 case BUILT_IN_GOMP_SECTIONS_END
:
2527 case BUILT_IN_GOMP_SECTIONS_END_CANCEL
:
2528 case BUILT_IN_GOMP_SINGLE_COPY_START
:
2529 case BUILT_IN_GOMP_SINGLE_COPY_END
:
2532 /* Fallthru to general call handling. */;
2535 /* Check if base is a global static variable that is not written
2537 if (callee
!= NULL_TREE
&& VAR_P (base
) && TREE_STATIC (base
))
2539 struct cgraph_node
*node
= cgraph_node::get (callee
);
2543 && (not_written
= ipa_reference_get_not_written_global (node
))
2544 && bitmap_bit_p (not_written
, ipa_reference_var_uid (base
)))
2548 /* Check if the base variable is call-clobbered. */
2550 return pt_solution_includes (gimple_call_clobber_set (call
), base
);
2551 else if ((TREE_CODE (base
) == MEM_REF
2552 || TREE_CODE (base
) == TARGET_MEM_REF
)
2553 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
)
2555 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (TREE_OPERAND (base
, 0));
2559 return pt_solutions_intersect (gimple_call_clobber_set (call
), &pi
->pt
);
2565 /* If the call in statement CALL may clobber the memory reference REF
2566 return true, otherwise return false. */
2569 call_may_clobber_ref_p (gcall
*call
, tree ref
)
2573 ao_ref_init (&r
, ref
);
2574 res
= call_may_clobber_ref_p_1 (call
, &r
);
2576 ++alias_stats
.call_may_clobber_ref_p_may_alias
;
2578 ++alias_stats
.call_may_clobber_ref_p_no_alias
;
2583 /* If the statement STMT may clobber the memory reference REF return true,
2584 otherwise return false. */
2587 stmt_may_clobber_ref_p_1 (gimple
*stmt
, ao_ref
*ref
, bool tbaa_p
)
2589 if (is_gimple_call (stmt
))
2591 tree lhs
= gimple_call_lhs (stmt
);
2593 && TREE_CODE (lhs
) != SSA_NAME
)
2596 ao_ref_init (&r
, lhs
);
2597 if (refs_may_alias_p_1 (ref
, &r
, tbaa_p
))
2601 return call_may_clobber_ref_p_1 (as_a
<gcall
*> (stmt
), ref
);
2603 else if (gimple_assign_single_p (stmt
))
2605 tree lhs
= gimple_assign_lhs (stmt
);
2606 if (TREE_CODE (lhs
) != SSA_NAME
)
2609 ao_ref_init (&r
, lhs
);
2610 return refs_may_alias_p_1 (ref
, &r
, tbaa_p
);
2613 else if (gimple_code (stmt
) == GIMPLE_ASM
)
2620 stmt_may_clobber_ref_p (gimple
*stmt
, tree ref
, bool tbaa_p
)
2623 ao_ref_init (&r
, ref
);
2624 return stmt_may_clobber_ref_p_1 (stmt
, &r
, tbaa_p
);
2627 /* Return true if store1 and store2 described by corresponding tuples
2628 <BASE, OFFSET, SIZE, MAX_SIZE> have the same size and store to the same
2632 same_addr_size_stores_p (tree base1
, poly_int64 offset1
, poly_int64 size1
,
2633 poly_int64 max_size1
,
2634 tree base2
, poly_int64 offset2
, poly_int64 size2
,
2635 poly_int64 max_size2
)
2637 /* Offsets need to be 0. */
2638 if (maybe_ne (offset1
, 0)
2639 || maybe_ne (offset2
, 0))
2642 bool base1_obj_p
= SSA_VAR_P (base1
);
2643 bool base2_obj_p
= SSA_VAR_P (base2
);
2645 /* We need one object. */
2646 if (base1_obj_p
== base2_obj_p
)
2648 tree obj
= base1_obj_p
? base1
: base2
;
2650 /* And we need one MEM_REF. */
2651 bool base1_memref_p
= TREE_CODE (base1
) == MEM_REF
;
2652 bool base2_memref_p
= TREE_CODE (base2
) == MEM_REF
;
2653 if (base1_memref_p
== base2_memref_p
)
2655 tree memref
= base1_memref_p
? base1
: base2
;
2657 /* Sizes need to be valid. */
2658 if (!known_size_p (max_size1
)
2659 || !known_size_p (max_size2
)
2660 || !known_size_p (size1
)
2661 || !known_size_p (size2
))
2664 /* Max_size needs to match size. */
2665 if (maybe_ne (max_size1
, size1
)
2666 || maybe_ne (max_size2
, size2
))
2669 /* Sizes need to match. */
2670 if (maybe_ne (size1
, size2
))
2674 /* Check that memref is a store to pointer with singleton points-to info. */
2675 if (!integer_zerop (TREE_OPERAND (memref
, 1)))
2677 tree ptr
= TREE_OPERAND (memref
, 0);
2678 if (TREE_CODE (ptr
) != SSA_NAME
)
2680 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (ptr
);
2681 unsigned int pt_uid
;
2683 || !pt_solution_singleton_or_null_p (&pi
->pt
, &pt_uid
))
2686 /* Be conservative with non-call exceptions when the address might
2688 if (cfun
->can_throw_non_call_exceptions
&& pi
->pt
.null
)
2691 /* Check that ptr points relative to obj. */
2692 unsigned int obj_uid
= DECL_PT_UID (obj
);
2693 if (obj_uid
!= pt_uid
)
2696 /* Check that the object size is the same as the store size. That ensures us
2697 that ptr points to the start of obj. */
2698 return (DECL_SIZE (obj
)
2699 && poly_int_tree_p (DECL_SIZE (obj
))
2700 && known_eq (wi::to_poly_offset (DECL_SIZE (obj
)), size1
));
2703 /* If STMT kills the memory reference REF return true, otherwise
2707 stmt_kills_ref_p (gimple
*stmt
, ao_ref
*ref
)
2709 if (!ao_ref_base (ref
))
2712 if (gimple_has_lhs (stmt
)
2713 && TREE_CODE (gimple_get_lhs (stmt
)) != SSA_NAME
2714 /* The assignment is not necessarily carried out if it can throw
2715 and we can catch it in the current function where we could inspect
2717 ??? We only need to care about the RHS throwing. For aggregate
2718 assignments or similar calls and non-call exceptions the LHS
2719 might throw as well. */
2720 && !stmt_can_throw_internal (cfun
, stmt
))
2722 tree lhs
= gimple_get_lhs (stmt
);
2723 /* If LHS is literally a base of the access we are done. */
2726 tree base
= ref
->ref
;
2727 tree innermost_dropped_array_ref
= NULL_TREE
;
2728 if (handled_component_p (base
))
2730 tree saved_lhs0
= NULL_TREE
;
2731 if (handled_component_p (lhs
))
2733 saved_lhs0
= TREE_OPERAND (lhs
, 0);
2734 TREE_OPERAND (lhs
, 0) = integer_zero_node
;
2738 /* Just compare the outermost handled component, if
2739 they are equal we have found a possible common
2741 tree saved_base0
= TREE_OPERAND (base
, 0);
2742 TREE_OPERAND (base
, 0) = integer_zero_node
;
2743 bool res
= operand_equal_p (lhs
, base
, 0);
2744 TREE_OPERAND (base
, 0) = saved_base0
;
2747 /* Remember if we drop an array-ref that we need to
2748 double-check not being at struct end. */
2749 if (TREE_CODE (base
) == ARRAY_REF
2750 || TREE_CODE (base
) == ARRAY_RANGE_REF
)
2751 innermost_dropped_array_ref
= base
;
2752 /* Otherwise drop handled components of the access. */
2755 while (handled_component_p (base
));
2757 TREE_OPERAND (lhs
, 0) = saved_lhs0
;
2759 /* Finally check if the lhs has the same address and size as the
2760 base candidate of the access. Watch out if we have dropped
2761 an array-ref that was at struct end, this means ref->ref may
2762 be outside of the TYPE_SIZE of its base. */
2763 if ((! innermost_dropped_array_ref
2764 || ! array_at_struct_end_p (innermost_dropped_array_ref
))
2766 || (((TYPE_SIZE (TREE_TYPE (lhs
))
2767 == TYPE_SIZE (TREE_TYPE (base
)))
2768 || (TYPE_SIZE (TREE_TYPE (lhs
))
2769 && TYPE_SIZE (TREE_TYPE (base
))
2770 && operand_equal_p (TYPE_SIZE (TREE_TYPE (lhs
)),
2771 TYPE_SIZE (TREE_TYPE (base
)),
2773 && operand_equal_p (lhs
, base
,
2775 | OEP_MATCH_SIDE_EFFECTS
))))
2779 /* Now look for non-literal equal bases with the restriction of
2780 handling constant offset and size. */
2781 /* For a must-alias check we need to be able to constrain
2782 the access properly. */
2783 if (!ref
->max_size_known_p ())
2785 poly_int64 size
, offset
, max_size
, ref_offset
= ref
->offset
;
2787 tree base
= get_ref_base_and_extent (lhs
, &offset
, &size
, &max_size
,
2789 /* We can get MEM[symbol: sZ, index: D.8862_1] here,
2790 so base == ref->base does not always hold. */
2791 if (base
!= ref
->base
)
2793 /* Try using points-to info. */
2794 if (same_addr_size_stores_p (base
, offset
, size
, max_size
, ref
->base
,
2795 ref
->offset
, ref
->size
, ref
->max_size
))
2798 /* If both base and ref->base are MEM_REFs, only compare the
2799 first operand, and if the second operand isn't equal constant,
2800 try to add the offsets into offset and ref_offset. */
2801 if (TREE_CODE (base
) == MEM_REF
&& TREE_CODE (ref
->base
) == MEM_REF
2802 && TREE_OPERAND (base
, 0) == TREE_OPERAND (ref
->base
, 0))
2804 if (!tree_int_cst_equal (TREE_OPERAND (base
, 1),
2805 TREE_OPERAND (ref
->base
, 1)))
2807 poly_offset_int off1
= mem_ref_offset (base
);
2808 off1
<<= LOG2_BITS_PER_UNIT
;
2810 poly_offset_int off2
= mem_ref_offset (ref
->base
);
2811 off2
<<= LOG2_BITS_PER_UNIT
;
2813 if (!off1
.to_shwi (&offset
) || !off2
.to_shwi (&ref_offset
))
2820 /* For a must-alias check we need to be able to constrain
2821 the access properly. */
2822 if (known_eq (size
, max_size
)
2823 && known_subrange_p (ref_offset
, ref
->max_size
, offset
, size
))
2827 if (is_gimple_call (stmt
))
2829 tree callee
= gimple_call_fndecl (stmt
);
2830 if (callee
!= NULL_TREE
2831 && gimple_call_builtin_p (stmt
, BUILT_IN_NORMAL
))
2832 switch (DECL_FUNCTION_CODE (callee
))
2836 tree ptr
= gimple_call_arg (stmt
, 0);
2837 tree base
= ao_ref_base (ref
);
2838 if (base
&& TREE_CODE (base
) == MEM_REF
2839 && TREE_OPERAND (base
, 0) == ptr
)
2844 case BUILT_IN_MEMCPY
:
2845 case BUILT_IN_MEMPCPY
:
2846 case BUILT_IN_MEMMOVE
:
2847 case BUILT_IN_MEMSET
:
2848 case BUILT_IN_MEMCPY_CHK
:
2849 case BUILT_IN_MEMPCPY_CHK
:
2850 case BUILT_IN_MEMMOVE_CHK
:
2851 case BUILT_IN_MEMSET_CHK
:
2852 case BUILT_IN_STRNCPY
:
2853 case BUILT_IN_STPNCPY
:
2855 /* For a must-alias check we need to be able to constrain
2856 the access properly. */
2857 if (!ref
->max_size_known_p ())
2859 tree dest
= gimple_call_arg (stmt
, 0);
2860 tree len
= gimple_call_arg (stmt
, 2);
2861 if (!poly_int_tree_p (len
))
2863 tree rbase
= ref
->base
;
2864 poly_offset_int roffset
= ref
->offset
;
2866 ao_ref_init_from_ptr_and_size (&dref
, dest
, len
);
2867 tree base
= ao_ref_base (&dref
);
2868 poly_offset_int offset
= dref
.offset
;
2869 if (!base
|| !known_size_p (dref
.size
))
2871 if (TREE_CODE (base
) == MEM_REF
)
2873 if (TREE_CODE (rbase
) != MEM_REF
)
2875 // Compare pointers.
2876 offset
+= mem_ref_offset (base
) << LOG2_BITS_PER_UNIT
;
2877 roffset
+= mem_ref_offset (rbase
) << LOG2_BITS_PER_UNIT
;
2878 base
= TREE_OPERAND (base
, 0);
2879 rbase
= TREE_OPERAND (rbase
, 0);
2882 && known_subrange_p (roffset
, ref
->max_size
, offset
,
2883 wi::to_poly_offset (len
)
2884 << LOG2_BITS_PER_UNIT
))
2889 case BUILT_IN_VA_END
:
2891 tree ptr
= gimple_call_arg (stmt
, 0);
2892 if (TREE_CODE (ptr
) == ADDR_EXPR
)
2894 tree base
= ao_ref_base (ref
);
2895 if (TREE_OPERAND (ptr
, 0) == base
)
2908 stmt_kills_ref_p (gimple
*stmt
, tree ref
)
2911 ao_ref_init (&r
, ref
);
2912 return stmt_kills_ref_p (stmt
, &r
);
2916 /* Walk the virtual use-def chain of VUSE until hitting the virtual operand
2917 TARGET or a statement clobbering the memory reference REF in which
2918 case false is returned. The walk starts with VUSE, one argument of PHI. */
2921 maybe_skip_until (gimple
*phi
, tree
&target
, basic_block target_bb
,
2922 ao_ref
*ref
, tree vuse
, unsigned int &limit
, bitmap
*visited
,
2923 bool abort_on_visited
,
2924 void *(*translate
)(ao_ref
*, tree
, void *, bool *),
2927 basic_block bb
= gimple_bb (phi
);
2930 *visited
= BITMAP_ALLOC (NULL
);
2932 bitmap_set_bit (*visited
, SSA_NAME_VERSION (PHI_RESULT (phi
)));
2934 /* Walk until we hit the target. */
2935 while (vuse
!= target
)
2937 gimple
*def_stmt
= SSA_NAME_DEF_STMT (vuse
);
2938 /* If we are searching for the target VUSE by walking up to
2939 TARGET_BB dominating the original PHI we are finished once
2940 we reach a default def or a definition in a block dominating
2941 that block. Update TARGET and return. */
2943 && (gimple_nop_p (def_stmt
)
2944 || dominated_by_p (CDI_DOMINATORS
,
2945 target_bb
, gimple_bb (def_stmt
))))
2951 /* Recurse for PHI nodes. */
2952 if (gimple_code (def_stmt
) == GIMPLE_PHI
)
2954 /* An already visited PHI node ends the walk successfully. */
2955 if (bitmap_bit_p (*visited
, SSA_NAME_VERSION (PHI_RESULT (def_stmt
))))
2956 return !abort_on_visited
;
2957 vuse
= get_continuation_for_phi (def_stmt
, ref
, limit
,
2958 visited
, abort_on_visited
,
2964 else if (gimple_nop_p (def_stmt
))
2968 /* A clobbering statement or the end of the IL ends it failing. */
2969 if ((int)limit
<= 0)
2972 if (stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
2974 bool disambiguate_only
= true;
2976 && (*translate
) (ref
, vuse
, data
, &disambiguate_only
) == NULL
)
2982 /* If we reach a new basic-block see if we already skipped it
2983 in a previous walk that ended successfully. */
2984 if (gimple_bb (def_stmt
) != bb
)
2986 if (!bitmap_set_bit (*visited
, SSA_NAME_VERSION (vuse
)))
2987 return !abort_on_visited
;
2988 bb
= gimple_bb (def_stmt
);
2990 vuse
= gimple_vuse (def_stmt
);
2996 /* Starting from a PHI node for the virtual operand of the memory reference
2997 REF find a continuation virtual operand that allows to continue walking
2998 statements dominating PHI skipping only statements that cannot possibly
2999 clobber REF. Decrements LIMIT for each alias disambiguation done
3000 and aborts the walk, returning NULL_TREE if it reaches zero.
3001 Returns NULL_TREE if no suitable virtual operand can be found. */
3004 get_continuation_for_phi (gimple
*phi
, ao_ref
*ref
,
3005 unsigned int &limit
, bitmap
*visited
,
3006 bool abort_on_visited
,
3007 void *(*translate
)(ao_ref
*, tree
, void *, bool *),
3010 unsigned nargs
= gimple_phi_num_args (phi
);
3012 /* Through a single-argument PHI we can simply look through. */
3014 return PHI_ARG_DEF (phi
, 0);
3016 /* For two or more arguments try to pairwise skip non-aliasing code
3017 until we hit the phi argument definition that dominates the other one. */
3018 basic_block phi_bb
= gimple_bb (phi
);
3022 /* Find a candidate for the virtual operand which definition
3023 dominates those of all others. */
3024 /* First look if any of the args themselves satisfy this. */
3025 for (i
= 0; i
< nargs
; ++i
)
3027 arg0
= PHI_ARG_DEF (phi
, i
);
3028 if (SSA_NAME_IS_DEFAULT_DEF (arg0
))
3030 basic_block def_bb
= gimple_bb (SSA_NAME_DEF_STMT (arg0
));
3031 if (def_bb
!= phi_bb
3032 && dominated_by_p (CDI_DOMINATORS
, phi_bb
, def_bb
))
3036 /* If not, look if we can reach such candidate by walking defs
3037 until we hit the immediate dominator. maybe_skip_until will
3039 basic_block dom
= get_immediate_dominator (CDI_DOMINATORS
, phi_bb
);
3041 /* Then check against the (to be) found candidate. */
3042 for (i
= 0; i
< nargs
; ++i
)
3044 arg1
= PHI_ARG_DEF (phi
, i
);
3047 else if (! maybe_skip_until (phi
, arg0
, dom
, ref
, arg1
, limit
, visited
,
3049 /* Do not translate when walking over
3053 gimple_bb (SSA_NAME_DEF_STMT (arg1
)),
3055 ? NULL
: translate
, data
))
3062 /* Based on the memory reference REF and its virtual use VUSE call
3063 WALKER for each virtual use that is equivalent to VUSE, including VUSE
3064 itself. That is, for each virtual use for which its defining statement
3065 does not clobber REF.
3067 WALKER is called with REF, the current virtual use and DATA. If
3068 WALKER returns non-NULL the walk stops and its result is returned.
3069 At the end of a non-successful walk NULL is returned.
3071 TRANSLATE if non-NULL is called with a pointer to REF, the virtual
3072 use which definition is a statement that may clobber REF and DATA.
3073 If TRANSLATE returns (void *)-1 the walk stops and NULL is returned.
3074 If TRANSLATE returns non-NULL the walk stops and its result is returned.
3075 If TRANSLATE returns NULL the walk continues and TRANSLATE is supposed
3076 to adjust REF and *DATA to make that valid.
3078 VALUEIZE if non-NULL is called with the next VUSE that is considered
3079 and return value is substituted for that. This can be used to
3080 implement optimistic value-numbering for example. Note that the
3081 VUSE argument is assumed to be valueized already.
3083 LIMIT specifies the number of alias queries we are allowed to do,
3084 the walk stops when it reaches zero and NULL is returned. LIMIT
3085 is decremented by the number of alias queries (plus adjustments
3086 done by the callbacks) upon return.
3088 TODO: Cache the vector of equivalent vuses per ref, vuse pair. */
3091 walk_non_aliased_vuses (ao_ref
*ref
, tree vuse
,
3092 void *(*walker
)(ao_ref
*, tree
, void *),
3093 void *(*translate
)(ao_ref
*, tree
, void *, bool *),
3094 tree (*valueize
)(tree
),
3095 unsigned &limit
, void *data
)
3097 bitmap visited
= NULL
;
3099 bool translated
= false;
3101 timevar_push (TV_ALIAS_STMT_WALK
);
3107 /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */
3108 res
= (*walker
) (ref
, vuse
, data
);
3110 if (res
== (void *)-1)
3115 /* Lookup succeeded. */
3116 else if (res
!= NULL
)
3121 vuse
= valueize (vuse
);
3128 def_stmt
= SSA_NAME_DEF_STMT (vuse
);
3129 if (gimple_nop_p (def_stmt
))
3131 else if (gimple_code (def_stmt
) == GIMPLE_PHI
)
3132 vuse
= get_continuation_for_phi (def_stmt
, ref
, limit
,
3133 &visited
, translated
, translate
, data
);
3136 if ((int)limit
<= 0)
3141 if (stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
3145 bool disambiguate_only
= false;
3146 res
= (*translate
) (ref
, vuse
, data
, &disambiguate_only
);
3147 /* Failed lookup and translation. */
3148 if (res
== (void *)-1)
3153 /* Lookup succeeded. */
3154 else if (res
!= NULL
)
3156 /* Translation succeeded, continue walking. */
3157 translated
= translated
|| !disambiguate_only
;
3159 vuse
= gimple_vuse (def_stmt
);
3165 BITMAP_FREE (visited
);
3167 timevar_pop (TV_ALIAS_STMT_WALK
);
3173 /* Based on the memory reference REF call WALKER for each vdef which
3174 defining statement may clobber REF, starting with VDEF. If REF
3175 is NULL_TREE, each defining statement is visited.
3177 WALKER is called with REF, the current vdef and DATA. If WALKER
3178 returns true the walk is stopped, otherwise it continues.
3180 If function entry is reached, FUNCTION_ENTRY_REACHED is set to true.
3181 The pointer may be NULL and then we do not track this information.
3183 At PHI nodes walk_aliased_vdefs forks into one walk for reach
3184 PHI argument (but only one walk continues on merge points), the
3185 return value is true if any of the walks was successful.
3187 The function returns the number of statements walked or -1 if
3188 LIMIT stmts were walked and the walk was aborted at this point.
3189 If LIMIT is zero the walk is not aborted. */
3192 walk_aliased_vdefs_1 (ao_ref
*ref
, tree vdef
,
3193 bool (*walker
)(ao_ref
*, tree
, void *), void *data
,
3194 bitmap
*visited
, unsigned int cnt
,
3195 bool *function_entry_reached
, unsigned limit
)
3199 gimple
*def_stmt
= SSA_NAME_DEF_STMT (vdef
);
3202 && !bitmap_set_bit (*visited
, SSA_NAME_VERSION (vdef
)))
3205 if (gimple_nop_p (def_stmt
))
3207 if (function_entry_reached
)
3208 *function_entry_reached
= true;
3211 else if (gimple_code (def_stmt
) == GIMPLE_PHI
)
3215 *visited
= BITMAP_ALLOC (NULL
);
3216 for (i
= 0; i
< gimple_phi_num_args (def_stmt
); ++i
)
3218 int res
= walk_aliased_vdefs_1 (ref
,
3219 gimple_phi_arg_def (def_stmt
, i
),
3220 walker
, data
, visited
, cnt
,
3221 function_entry_reached
, limit
);
3229 /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */
3234 || stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
3235 && (*walker
) (ref
, vdef
, data
))
3238 vdef
= gimple_vuse (def_stmt
);
3244 walk_aliased_vdefs (ao_ref
*ref
, tree vdef
,
3245 bool (*walker
)(ao_ref
*, tree
, void *), void *data
,
3247 bool *function_entry_reached
, unsigned int limit
)
3249 bitmap local_visited
= NULL
;
3252 timevar_push (TV_ALIAS_STMT_WALK
);
3254 if (function_entry_reached
)
3255 *function_entry_reached
= false;
3257 ret
= walk_aliased_vdefs_1 (ref
, vdef
, walker
, data
,
3258 visited
? visited
: &local_visited
, 0,
3259 function_entry_reached
, limit
);
3261 BITMAP_FREE (local_visited
);
3263 timevar_pop (TV_ALIAS_STMT_WALK
);