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;
881 /* Choose bases and base types to search for. */
883 while (handled_component_p (base1
))
884 base1
= TREE_OPERAND (base1
, 0);
885 type1
= TREE_TYPE (base1
);
887 while (handled_component_p (base2
))
888 base2
= TREE_OPERAND (base2
, 0);
889 type2
= TREE_TYPE (base2
);
891 /* Now search for the type1 in the access path of ref2. This
892 would be a common base for doing offset based disambiguation on.
893 This however only makes sense if type2 is big enough to hold type1. */
894 int cmp_outer
= compare_type_sizes (type2
, type1
);
900 /* We walk from inner type to the outer types. If type we see is
901 already too large to be part of type1, terminate the search. */
902 int cmp
= compare_type_sizes (type1
, TREE_TYPE (*refp
));
905 /* If types may be of same size, see if we can decide about their
909 same_p2
= same_type_for_tbaa (TREE_TYPE (*refp
), type1
);
912 /* In case we can't decide whether types are same try to
913 continue looking for the exact match.
914 Remember however that we possibly saw a match
915 to bypass the access path continuations tests we do later. */
919 if (!handled_component_p (*refp
))
921 refp
= &TREE_OPERAND (*refp
, 0);
925 poly_int64 offadj
, sztmp
, msztmp
;
928 /* We assume that arrays can overlap by multiple of their elements
929 size as tested in gcc.dg/torture/alias-2.c.
930 This partial overlap happen only when both arrays are bases of
931 the access and not contained within another component ref.
932 To be safe we also assume partial overlap for VLAs. */
933 if (TREE_CODE (TREE_TYPE (base1
)) == ARRAY_TYPE
934 && (!TYPE_SIZE (TREE_TYPE (base1
))
935 || TREE_CODE (TYPE_SIZE (TREE_TYPE (base1
))) != INTEGER_CST
936 || (*refp
== base2
&& !ref2_is_decl
)))
938 ++alias_stats
.aliasing_component_refs_p_may_alias
;
942 get_ref_base_and_extent (*refp
, &offadj
, &sztmp
, &msztmp
, &reverse
);
944 get_ref_base_and_extent (base1
, &offadj
, &sztmp
, &msztmp
, &reverse
);
946 if (ranges_maybe_overlap_p (offset1
, max_size1
, offset2
, max_size2
))
948 ++alias_stats
.aliasing_component_refs_p_may_alias
;
953 ++alias_stats
.aliasing_component_refs_p_no_alias
;
959 /* If we didn't find a common base, try the other way around. */
965 int cmp
= compare_type_sizes (type2
, TREE_TYPE (*refp
));
968 /* If types may be of same size, see if we can decide about their
972 same_p1
= same_type_for_tbaa (TREE_TYPE (*refp
), type2
);
978 if (!handled_component_p (*refp
))
980 refp
= &TREE_OPERAND (*refp
, 0);
984 poly_int64 offadj
, sztmp
, msztmp
;
987 if (TREE_CODE (TREE_TYPE (base2
)) == ARRAY_TYPE
988 && (!TYPE_SIZE (TREE_TYPE (base2
))
989 || TREE_CODE (TYPE_SIZE (TREE_TYPE (base2
))) != INTEGER_CST
990 || (*refp
== base1
&& !ref2_is_decl
)))
992 ++alias_stats
.aliasing_component_refs_p_may_alias
;
996 get_ref_base_and_extent (*refp
, &offadj
, &sztmp
, &msztmp
, &reverse
);
998 get_ref_base_and_extent (base2
, &offadj
, &sztmp
, &msztmp
, &reverse
);
1000 if (ranges_maybe_overlap_p (offset1
, max_size1
, offset2
, max_size2
))
1002 ++alias_stats
.aliasing_component_refs_p_may_alias
;
1007 ++alias_stats
.aliasing_component_refs_p_no_alias
;
1013 /* In the following code we make an assumption that the types in access
1014 paths do not overlap and thus accesses alias only if one path can be
1015 continuation of another. If we was not able to decide about equivalence,
1016 we need to give up. */
1020 /* If we have two type access paths B1.path1 and B2.path2 they may
1021 only alias if either B1 is in B2.path2 or B2 is in B1.path1.
1022 But we can still have a path that goes B1.path1...B2.path2 with
1023 a part that we do not see. So we can only disambiguate now
1024 if there is no B2 in the tail of path1 and no B1 on the
1026 if (compare_type_sizes (TREE_TYPE (ref2
), type1
) >= 0
1027 && type_has_components_p (TREE_TYPE (ref2
))
1028 && (base1_alias_set
== ref2_alias_set
1029 || alias_set_subset_of (base1_alias_set
, ref2_alias_set
)))
1031 ++alias_stats
.aliasing_component_refs_p_may_alias
;
1034 /* If this is ptr vs. decl then we know there is no ptr ... decl path. */
1036 && compare_type_sizes (TREE_TYPE (ref1
), type2
) >= 0
1037 && type_has_components_p (TREE_TYPE (ref1
))
1038 && (base2_alias_set
== ref1_alias_set
1039 || alias_set_subset_of (base2_alias_set
, ref1_alias_set
)))
1041 ++alias_stats
.aliasing_component_refs_p_may_alias
;
1044 ++alias_stats
.aliasing_component_refs_p_no_alias
;
1048 /* Return true if we can determine that component references REF1 and REF2,
1049 that are within a common DECL, cannot overlap. */
1052 nonoverlapping_component_refs_of_decl_p (tree ref1
, tree ref2
)
1054 auto_vec
<tree
, 16> component_refs1
;
1055 auto_vec
<tree
, 16> component_refs2
;
1057 /* Create the stack of handled components for REF1. */
1058 while (handled_component_p (ref1
))
1060 component_refs1
.safe_push (ref1
);
1061 ref1
= TREE_OPERAND (ref1
, 0);
1063 if (TREE_CODE (ref1
) == MEM_REF
)
1065 if (!integer_zerop (TREE_OPERAND (ref1
, 1)))
1067 ++alias_stats
.nonoverlapping_component_refs_of_decl_p_may_alias
;
1070 ref1
= TREE_OPERAND (TREE_OPERAND (ref1
, 0), 0);
1073 /* Create the stack of handled components for REF2. */
1074 while (handled_component_p (ref2
))
1076 component_refs2
.safe_push (ref2
);
1077 ref2
= TREE_OPERAND (ref2
, 0);
1079 if (TREE_CODE (ref2
) == MEM_REF
)
1081 if (!integer_zerop (TREE_OPERAND (ref2
, 1)))
1083 ++alias_stats
.nonoverlapping_component_refs_of_decl_p_may_alias
;
1086 ref2
= TREE_OPERAND (TREE_OPERAND (ref2
, 0), 0);
1089 /* Bases must be either same or uncomparable. */
1090 gcc_checking_assert (ref1
== ref2
1091 || (DECL_P (ref1
) && DECL_P (ref2
)
1092 && compare_base_decls (ref1
, ref2
) != 0));
1094 /* Pop the stacks in parallel and examine the COMPONENT_REFs of the same
1095 rank. This is sufficient because we start from the same DECL and you
1096 cannot reference several fields at a time with COMPONENT_REFs (unlike
1097 with ARRAY_RANGE_REFs for arrays) so you always need the same number
1098 of them to access a sub-component, unless you're in a union, in which
1099 case the return value will precisely be false. */
1104 if (component_refs1
.is_empty ())
1106 ++alias_stats
.nonoverlapping_component_refs_of_decl_p_may_alias
;
1109 ref1
= component_refs1
.pop ();
1111 while (!RECORD_OR_UNION_TYPE_P (TREE_TYPE (TREE_OPERAND (ref1
, 0))));
1115 if (component_refs2
.is_empty ())
1117 ++alias_stats
.nonoverlapping_component_refs_of_decl_p_may_alias
;
1120 ref2
= component_refs2
.pop ();
1122 while (!RECORD_OR_UNION_TYPE_P (TREE_TYPE (TREE_OPERAND (ref2
, 0))));
1124 /* Beware of BIT_FIELD_REF. */
1125 if (TREE_CODE (ref1
) != COMPONENT_REF
1126 || TREE_CODE (ref2
) != COMPONENT_REF
)
1128 ++alias_stats
.nonoverlapping_component_refs_of_decl_p_may_alias
;
1132 tree field1
= TREE_OPERAND (ref1
, 1);
1133 tree field2
= TREE_OPERAND (ref2
, 1);
1135 /* ??? We cannot simply use the type of operand #0 of the refs here
1136 as the Fortran compiler smuggles type punning into COMPONENT_REFs
1137 for common blocks instead of using unions like everyone else. */
1138 tree type1
= DECL_CONTEXT (field1
);
1139 tree type2
= DECL_CONTEXT (field2
);
1141 /* We cannot disambiguate fields in a union or qualified union. */
1142 if (type1
!= type2
|| TREE_CODE (type1
) != RECORD_TYPE
)
1144 ++alias_stats
.nonoverlapping_component_refs_of_decl_p_may_alias
;
1148 if (field1
!= field2
)
1150 /* A field and its representative need to be considered the
1152 if (DECL_BIT_FIELD_REPRESENTATIVE (field1
) == field2
1153 || DECL_BIT_FIELD_REPRESENTATIVE (field2
) == field1
)
1155 ++alias_stats
.nonoverlapping_component_refs_of_decl_p_may_alias
;
1158 /* Different fields of the same record type cannot overlap.
1159 ??? Bitfields can overlap at RTL level so punt on them. */
1160 if (DECL_BIT_FIELD (field1
) && DECL_BIT_FIELD (field2
))
1162 ++alias_stats
.nonoverlapping_component_refs_of_decl_p_may_alias
;
1165 ++alias_stats
.nonoverlapping_component_refs_of_decl_p_no_alias
;
1170 ++alias_stats
.nonoverlapping_component_refs_of_decl_p_may_alias
;
1174 /* qsort compare function to sort FIELD_DECLs after their
1175 DECL_FIELD_CONTEXT TYPE_UID. */
1178 ncr_compar (const void *field1_
, const void *field2_
)
1180 const_tree field1
= *(const_tree
*) const_cast <void *>(field1_
);
1181 const_tree field2
= *(const_tree
*) const_cast <void *>(field2_
);
1182 unsigned int uid1
= TYPE_UID (DECL_FIELD_CONTEXT (field1
));
1183 unsigned int uid2
= TYPE_UID (DECL_FIELD_CONTEXT (field2
));
1186 else if (uid1
> uid2
)
1191 /* Return true if we can determine that the fields referenced cannot
1192 overlap for any pair of objects. */
1195 nonoverlapping_component_refs_p (const_tree x
, const_tree y
)
1197 if (!flag_strict_aliasing
1199 || !handled_component_p (x
)
1200 || !handled_component_p (y
))
1202 ++alias_stats
.nonoverlapping_component_refs_p_may_alias
;
1206 auto_vec
<const_tree
, 16> fieldsx
;
1207 while (handled_component_p (x
))
1209 if (TREE_CODE (x
) == COMPONENT_REF
)
1211 tree field
= TREE_OPERAND (x
, 1);
1212 tree type
= DECL_FIELD_CONTEXT (field
);
1213 if (TREE_CODE (type
) == RECORD_TYPE
)
1214 fieldsx
.safe_push (field
);
1216 else if (TREE_CODE (x
) == VIEW_CONVERT_EXPR
)
1217 fieldsx
.truncate (0);
1218 x
= TREE_OPERAND (x
, 0);
1220 if (fieldsx
.length () == 0)
1222 auto_vec
<const_tree
, 16> fieldsy
;
1223 while (handled_component_p (y
))
1225 if (TREE_CODE (y
) == COMPONENT_REF
)
1227 tree field
= TREE_OPERAND (y
, 1);
1228 tree type
= DECL_FIELD_CONTEXT (field
);
1229 if (TREE_CODE (type
) == RECORD_TYPE
)
1230 fieldsy
.safe_push (TREE_OPERAND (y
, 1));
1232 else if (TREE_CODE (y
) == VIEW_CONVERT_EXPR
)
1233 fieldsy
.truncate (0);
1234 y
= TREE_OPERAND (y
, 0);
1236 if (fieldsy
.length () == 0)
1238 ++alias_stats
.nonoverlapping_component_refs_p_may_alias
;
1242 /* Most common case first. */
1243 if (fieldsx
.length () == 1
1244 && fieldsy
.length () == 1)
1246 if ((DECL_FIELD_CONTEXT (fieldsx
[0])
1247 == DECL_FIELD_CONTEXT (fieldsy
[0]))
1248 && fieldsx
[0] != fieldsy
[0]
1249 && !(DECL_BIT_FIELD (fieldsx
[0]) && DECL_BIT_FIELD (fieldsy
[0])))
1251 ++alias_stats
.nonoverlapping_component_refs_p_no_alias
;
1256 ++alias_stats
.nonoverlapping_component_refs_p_may_alias
;
1261 if (fieldsx
.length () == 2)
1263 if (ncr_compar (&fieldsx
[0], &fieldsx
[1]) == 1)
1264 std::swap (fieldsx
[0], fieldsx
[1]);
1267 fieldsx
.qsort (ncr_compar
);
1269 if (fieldsy
.length () == 2)
1271 if (ncr_compar (&fieldsy
[0], &fieldsy
[1]) == 1)
1272 std::swap (fieldsy
[0], fieldsy
[1]);
1275 fieldsy
.qsort (ncr_compar
);
1277 unsigned i
= 0, j
= 0;
1280 const_tree fieldx
= fieldsx
[i
];
1281 const_tree fieldy
= fieldsy
[j
];
1282 tree typex
= DECL_FIELD_CONTEXT (fieldx
);
1283 tree typey
= DECL_FIELD_CONTEXT (fieldy
);
1286 /* We're left with accessing different fields of a structure,
1287 no possible overlap. */
1288 if (fieldx
!= fieldy
)
1290 /* A field and its representative need to be considered the
1292 if (DECL_BIT_FIELD_REPRESENTATIVE (fieldx
) == fieldy
1293 || DECL_BIT_FIELD_REPRESENTATIVE (fieldy
) == fieldx
)
1295 ++alias_stats
.nonoverlapping_component_refs_p_may_alias
;
1298 /* Different fields of the same record type cannot overlap.
1299 ??? Bitfields can overlap at RTL level so punt on them. */
1300 if (DECL_BIT_FIELD (fieldx
) && DECL_BIT_FIELD (fieldy
))
1302 ++alias_stats
.nonoverlapping_component_refs_p_may_alias
;
1305 ++alias_stats
.nonoverlapping_component_refs_p_no_alias
;
1309 if (TYPE_UID (typex
) < TYPE_UID (typey
))
1312 if (i
== fieldsx
.length ())
1318 if (j
== fieldsy
.length ())
1324 ++alias_stats
.nonoverlapping_component_refs_p_may_alias
;
1329 /* Return true if two memory references based on the variables BASE1
1330 and BASE2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and
1331 [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. REF1 and REF2
1332 if non-NULL are the complete memory reference trees. */
1335 decl_refs_may_alias_p (tree ref1
, tree base1
,
1336 poly_int64 offset1
, poly_int64 max_size1
,
1337 tree ref2
, tree base2
,
1338 poly_int64 offset2
, poly_int64 max_size2
)
1340 gcc_checking_assert (DECL_P (base1
) && DECL_P (base2
));
1342 /* If both references are based on different variables, they cannot alias. */
1343 if (compare_base_decls (base1
, base2
) == 0)
1346 /* If both references are based on the same variable, they cannot alias if
1347 the accesses do not overlap. */
1348 if (!ranges_maybe_overlap_p (offset1
, max_size1
, offset2
, max_size2
))
1351 /* For components with variable position, the above test isn't sufficient,
1352 so we disambiguate component references manually. */
1354 && handled_component_p (ref1
) && handled_component_p (ref2
)
1355 && nonoverlapping_component_refs_of_decl_p (ref1
, ref2
))
1361 /* Return true if an indirect reference based on *PTR1 constrained
1362 to [OFFSET1, OFFSET1 + MAX_SIZE1) may alias a variable based on BASE2
1363 constrained to [OFFSET2, OFFSET2 + MAX_SIZE2). *PTR1 and BASE2 have
1364 the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1
1365 in which case they are computed on-demand. REF1 and REF2
1366 if non-NULL are the complete memory reference trees. */
1369 indirect_ref_may_alias_decl_p (tree ref1 ATTRIBUTE_UNUSED
, tree base1
,
1370 poly_int64 offset1
, poly_int64 max_size1
,
1371 alias_set_type ref1_alias_set
,
1372 alias_set_type base1_alias_set
,
1373 tree ref2 ATTRIBUTE_UNUSED
, tree base2
,
1374 poly_int64 offset2
, poly_int64 max_size2
,
1375 alias_set_type ref2_alias_set
,
1376 alias_set_type base2_alias_set
, bool tbaa_p
)
1379 tree ptrtype1
, dbase2
;
1381 gcc_checking_assert ((TREE_CODE (base1
) == MEM_REF
1382 || TREE_CODE (base1
) == TARGET_MEM_REF
)
1385 ptr1
= TREE_OPERAND (base1
, 0);
1386 poly_offset_int moff
= mem_ref_offset (base1
) << LOG2_BITS_PER_UNIT
;
1388 /* If only one reference is based on a variable, they cannot alias if
1389 the pointer access is beyond the extent of the variable access.
1390 (the pointer base cannot validly point to an offset less than zero
1392 ??? IVOPTs creates bases that do not honor this restriction,
1393 so do not apply this optimization for TARGET_MEM_REFs. */
1394 if (TREE_CODE (base1
) != TARGET_MEM_REF
1395 && !ranges_maybe_overlap_p (offset1
+ moff
, -1, offset2
, max_size2
))
1397 /* They also cannot alias if the pointer may not point to the decl. */
1398 if (!ptr_deref_may_alias_decl_p (ptr1
, base2
))
1401 /* Disambiguations that rely on strict aliasing rules follow. */
1402 if (!flag_strict_aliasing
|| !tbaa_p
)
1405 ptrtype1
= TREE_TYPE (TREE_OPERAND (base1
, 1));
1407 /* If the alias set for a pointer access is zero all bets are off. */
1408 if (base1_alias_set
== 0)
1411 /* When we are trying to disambiguate an access with a pointer dereference
1412 as base versus one with a decl as base we can use both the size
1413 of the decl and its dynamic type for extra disambiguation.
1414 ??? We do not know anything about the dynamic type of the decl
1415 other than that its alias-set contains base2_alias_set as a subset
1416 which does not help us here. */
1417 /* As we know nothing useful about the dynamic type of the decl just
1418 use the usual conflict check rather than a subset test.
1419 ??? We could introduce -fvery-strict-aliasing when the language
1420 does not allow decls to have a dynamic type that differs from their
1421 static type. Then we can check
1422 !alias_set_subset_of (base1_alias_set, base2_alias_set) instead. */
1423 if (base1_alias_set
!= base2_alias_set
1424 && !alias_sets_conflict_p (base1_alias_set
, base2_alias_set
))
1426 /* If the size of the access relevant for TBAA through the pointer
1427 is bigger than the size of the decl we can't possibly access the
1428 decl via that pointer. */
1429 if (/* ??? This in turn may run afoul when a decl of type T which is
1430 a member of union type U is accessed through a pointer to
1431 type U and sizeof T is smaller than sizeof U. */
1432 TREE_CODE (TREE_TYPE (ptrtype1
)) != UNION_TYPE
1433 && TREE_CODE (TREE_TYPE (ptrtype1
)) != QUAL_UNION_TYPE
1434 && compare_sizes (DECL_SIZE (base2
),
1435 TYPE_SIZE (TREE_TYPE (ptrtype1
))) < 0)
1441 /* If the decl is accessed via a MEM_REF, reconstruct the base
1442 we can use for TBAA and an appropriately adjusted offset. */
1444 while (handled_component_p (dbase2
))
1445 dbase2
= TREE_OPERAND (dbase2
, 0);
1446 poly_int64 doffset1
= offset1
;
1447 poly_offset_int doffset2
= offset2
;
1448 if (TREE_CODE (dbase2
) == MEM_REF
1449 || TREE_CODE (dbase2
) == TARGET_MEM_REF
)
1451 doffset2
-= mem_ref_offset (dbase2
) << LOG2_BITS_PER_UNIT
;
1452 tree ptrtype2
= TREE_TYPE (TREE_OPERAND (dbase2
, 1));
1453 /* If second reference is view-converted, give up now. */
1454 if (same_type_for_tbaa (TREE_TYPE (dbase2
), TREE_TYPE (ptrtype2
)) != 1)
1458 /* If first reference is view-converted, give up now. */
1459 if (same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (ptrtype1
)) != 1)
1462 /* If both references are through the same type, they do not alias
1463 if the accesses do not overlap. This does extra disambiguation
1464 for mixed/pointer accesses but requires strict aliasing.
1465 For MEM_REFs we require that the component-ref offset we computed
1466 is relative to the start of the type which we ensure by
1467 comparing rvalue and access type and disregarding the constant
1470 But avoid treating variable length arrays as "objects", instead assume they
1471 can overlap by an exact multiple of their element size.
1472 See gcc.dg/torture/alias-2.c. */
1473 if (((TREE_CODE (base1
) != TARGET_MEM_REF
1474 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1475 && (TREE_CODE (dbase2
) != TARGET_MEM_REF
1476 || (!TMR_INDEX (dbase2
) && !TMR_INDEX2 (base2
))))
1477 && same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (dbase2
)) == 1
1478 && (TREE_CODE (TREE_TYPE (base1
)) != ARRAY_TYPE
1479 || (TYPE_SIZE (TREE_TYPE (base1
))
1480 && TREE_CODE (TYPE_SIZE (TREE_TYPE (base1
))) == INTEGER_CST
)))
1481 return ranges_maybe_overlap_p (doffset1
, max_size1
, doffset2
, max_size2
);
1484 && nonoverlapping_component_refs_p (ref1
, ref2
))
1487 /* Do access-path based disambiguation. */
1489 && (handled_component_p (ref1
) || handled_component_p (ref2
)))
1490 return aliasing_component_refs_p (ref1
,
1491 ref1_alias_set
, base1_alias_set
,
1494 ref2_alias_set
, base2_alias_set
,
1496 /* Only if the other reference is actual
1497 decl we can safely check only toplevel
1498 part of access path 1. */
1499 same_type_for_tbaa (TREE_TYPE (dbase2
),
1506 /* Return true if two indirect references based on *PTR1
1507 and *PTR2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and
1508 [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. *PTR1 and *PTR2 have
1509 the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1
1510 in which case they are computed on-demand. REF1 and REF2
1511 if non-NULL are the complete memory reference trees. */
1514 indirect_refs_may_alias_p (tree ref1 ATTRIBUTE_UNUSED
, tree base1
,
1515 poly_int64 offset1
, poly_int64 max_size1
,
1516 alias_set_type ref1_alias_set
,
1517 alias_set_type base1_alias_set
,
1518 tree ref2 ATTRIBUTE_UNUSED
, tree base2
,
1519 poly_int64 offset2
, poly_int64 max_size2
,
1520 alias_set_type ref2_alias_set
,
1521 alias_set_type base2_alias_set
, bool tbaa_p
)
1525 tree ptrtype1
, ptrtype2
;
1527 gcc_checking_assert ((TREE_CODE (base1
) == MEM_REF
1528 || TREE_CODE (base1
) == TARGET_MEM_REF
)
1529 && (TREE_CODE (base2
) == MEM_REF
1530 || TREE_CODE (base2
) == TARGET_MEM_REF
));
1532 ptr1
= TREE_OPERAND (base1
, 0);
1533 ptr2
= TREE_OPERAND (base2
, 0);
1535 /* If both bases are based on pointers they cannot alias if they may not
1536 point to the same memory object or if they point to the same object
1537 and the accesses do not overlap. */
1538 if ((!cfun
|| gimple_in_ssa_p (cfun
))
1539 && operand_equal_p (ptr1
, ptr2
, 0)
1540 && (((TREE_CODE (base1
) != TARGET_MEM_REF
1541 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1542 && (TREE_CODE (base2
) != TARGET_MEM_REF
1543 || (!TMR_INDEX (base2
) && !TMR_INDEX2 (base2
))))
1544 || (TREE_CODE (base1
) == TARGET_MEM_REF
1545 && TREE_CODE (base2
) == TARGET_MEM_REF
1546 && (TMR_STEP (base1
) == TMR_STEP (base2
)
1547 || (TMR_STEP (base1
) && TMR_STEP (base2
)
1548 && operand_equal_p (TMR_STEP (base1
),
1549 TMR_STEP (base2
), 0)))
1550 && (TMR_INDEX (base1
) == TMR_INDEX (base2
)
1551 || (TMR_INDEX (base1
) && TMR_INDEX (base2
)
1552 && operand_equal_p (TMR_INDEX (base1
),
1553 TMR_INDEX (base2
), 0)))
1554 && (TMR_INDEX2 (base1
) == TMR_INDEX2 (base2
)
1555 || (TMR_INDEX2 (base1
) && TMR_INDEX2 (base2
)
1556 && operand_equal_p (TMR_INDEX2 (base1
),
1557 TMR_INDEX2 (base2
), 0))))))
1559 poly_offset_int moff1
= mem_ref_offset (base1
) << LOG2_BITS_PER_UNIT
;
1560 poly_offset_int moff2
= mem_ref_offset (base2
) << LOG2_BITS_PER_UNIT
;
1561 return ranges_maybe_overlap_p (offset1
+ moff1
, max_size1
,
1562 offset2
+ moff2
, max_size2
);
1564 if (!ptr_derefs_may_alias_p (ptr1
, ptr2
))
1567 /* Disambiguations that rely on strict aliasing rules follow. */
1568 if (!flag_strict_aliasing
|| !tbaa_p
)
1571 ptrtype1
= TREE_TYPE (TREE_OPERAND (base1
, 1));
1572 ptrtype2
= TREE_TYPE (TREE_OPERAND (base2
, 1));
1574 /* If the alias set for a pointer access is zero all bets are off. */
1575 if (base1_alias_set
== 0
1576 || base2_alias_set
== 0)
1579 /* Do type-based disambiguation. */
1580 if (base1_alias_set
!= base2_alias_set
1581 && !alias_sets_conflict_p (base1_alias_set
, base2_alias_set
))
1584 /* If either reference is view-converted, give up now. */
1585 if (same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (ptrtype1
)) != 1
1586 || same_type_for_tbaa (TREE_TYPE (base2
), TREE_TYPE (ptrtype2
)) != 1)
1589 /* If both references are through the same type, they do not alias
1590 if the accesses do not overlap. This does extra disambiguation
1591 for mixed/pointer accesses but requires strict aliasing. */
1592 if ((TREE_CODE (base1
) != TARGET_MEM_REF
1593 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1594 && (TREE_CODE (base2
) != TARGET_MEM_REF
1595 || (!TMR_INDEX (base2
) && !TMR_INDEX2 (base2
)))
1596 && same_type_for_tbaa (TREE_TYPE (ptrtype1
),
1597 TREE_TYPE (ptrtype2
)) == 1
1598 /* But avoid treating arrays as "objects", instead assume they
1599 can overlap by an exact multiple of their element size.
1600 See gcc.dg/torture/alias-2.c. */
1601 && TREE_CODE (TREE_TYPE (ptrtype1
)) != ARRAY_TYPE
)
1602 return ranges_maybe_overlap_p (offset1
, max_size1
, offset2
, max_size2
);
1605 && nonoverlapping_component_refs_p (ref1
, ref2
))
1608 /* Do access-path based disambiguation. */
1610 && (handled_component_p (ref1
) || handled_component_p (ref2
)))
1611 return aliasing_component_refs_p (ref1
,
1612 ref1_alias_set
, base1_alias_set
,
1615 ref2_alias_set
, base2_alias_set
,
1616 offset2
, max_size2
, false);
1621 /* Return true, if the two memory references REF1 and REF2 may alias. */
1624 refs_may_alias_p_2 (ao_ref
*ref1
, ao_ref
*ref2
, bool tbaa_p
)
1627 poly_int64 offset1
= 0, offset2
= 0;
1628 poly_int64 max_size1
= -1, max_size2
= -1;
1629 bool var1_p
, var2_p
, ind1_p
, ind2_p
;
1631 gcc_checking_assert ((!ref1
->ref
1632 || TREE_CODE (ref1
->ref
) == SSA_NAME
1633 || DECL_P (ref1
->ref
)
1634 || TREE_CODE (ref1
->ref
) == STRING_CST
1635 || handled_component_p (ref1
->ref
)
1636 || TREE_CODE (ref1
->ref
) == MEM_REF
1637 || TREE_CODE (ref1
->ref
) == TARGET_MEM_REF
)
1639 || TREE_CODE (ref2
->ref
) == SSA_NAME
1640 || DECL_P (ref2
->ref
)
1641 || TREE_CODE (ref2
->ref
) == STRING_CST
1642 || handled_component_p (ref2
->ref
)
1643 || TREE_CODE (ref2
->ref
) == MEM_REF
1644 || TREE_CODE (ref2
->ref
) == TARGET_MEM_REF
));
1646 /* Decompose the references into their base objects and the access. */
1647 base1
= ao_ref_base (ref1
);
1648 offset1
= ref1
->offset
;
1649 max_size1
= ref1
->max_size
;
1650 base2
= ao_ref_base (ref2
);
1651 offset2
= ref2
->offset
;
1652 max_size2
= ref2
->max_size
;
1654 /* We can end up with registers or constants as bases for example from
1655 *D.1663_44 = VIEW_CONVERT_EXPR<struct DB_LSN>(__tmp$B0F64_59);
1656 which is seen as a struct copy. */
1657 if (TREE_CODE (base1
) == SSA_NAME
1658 || TREE_CODE (base1
) == CONST_DECL
1659 || TREE_CODE (base1
) == CONSTRUCTOR
1660 || TREE_CODE (base1
) == ADDR_EXPR
1661 || CONSTANT_CLASS_P (base1
)
1662 || TREE_CODE (base2
) == SSA_NAME
1663 || TREE_CODE (base2
) == CONST_DECL
1664 || TREE_CODE (base2
) == CONSTRUCTOR
1665 || TREE_CODE (base2
) == ADDR_EXPR
1666 || CONSTANT_CLASS_P (base2
))
1669 /* We can end up referring to code via function and label decls.
1670 As we likely do not properly track code aliases conservatively
1672 if (TREE_CODE (base1
) == FUNCTION_DECL
1673 || TREE_CODE (base1
) == LABEL_DECL
1674 || TREE_CODE (base2
) == FUNCTION_DECL
1675 || TREE_CODE (base2
) == LABEL_DECL
)
1678 /* Two volatile accesses always conflict. */
1679 if (ref1
->volatile_p
1680 && ref2
->volatile_p
)
1683 /* Defer to simple offset based disambiguation if we have
1684 references based on two decls. Do this before defering to
1685 TBAA to handle must-alias cases in conformance with the
1686 GCC extension of allowing type-punning through unions. */
1687 var1_p
= DECL_P (base1
);
1688 var2_p
= DECL_P (base2
);
1689 if (var1_p
&& var2_p
)
1690 return decl_refs_may_alias_p (ref1
->ref
, base1
, offset1
, max_size1
,
1691 ref2
->ref
, base2
, offset2
, max_size2
);
1693 /* Handle restrict based accesses.
1694 ??? ao_ref_base strips inner MEM_REF [&decl], recover from that
1696 tree rbase1
= base1
;
1697 tree rbase2
= base2
;
1702 while (handled_component_p (rbase1
))
1703 rbase1
= TREE_OPERAND (rbase1
, 0);
1709 while (handled_component_p (rbase2
))
1710 rbase2
= TREE_OPERAND (rbase2
, 0);
1712 if (rbase1
&& rbase2
1713 && (TREE_CODE (base1
) == MEM_REF
|| TREE_CODE (base1
) == TARGET_MEM_REF
)
1714 && (TREE_CODE (base2
) == MEM_REF
|| TREE_CODE (base2
) == TARGET_MEM_REF
)
1715 /* If the accesses are in the same restrict clique... */
1716 && MR_DEPENDENCE_CLIQUE (base1
) == MR_DEPENDENCE_CLIQUE (base2
)
1717 /* But based on different pointers they do not alias. */
1718 && MR_DEPENDENCE_BASE (base1
) != MR_DEPENDENCE_BASE (base2
))
1721 ind1_p
= (TREE_CODE (base1
) == MEM_REF
1722 || TREE_CODE (base1
) == TARGET_MEM_REF
);
1723 ind2_p
= (TREE_CODE (base2
) == MEM_REF
1724 || TREE_CODE (base2
) == TARGET_MEM_REF
);
1726 /* Canonicalize the pointer-vs-decl case. */
1727 if (ind1_p
&& var2_p
)
1729 std::swap (offset1
, offset2
);
1730 std::swap (max_size1
, max_size2
);
1731 std::swap (base1
, base2
);
1732 std::swap (ref1
, ref2
);
1739 /* First defer to TBAA if possible. */
1741 && flag_strict_aliasing
1742 && !alias_sets_conflict_p (ao_ref_alias_set (ref1
),
1743 ao_ref_alias_set (ref2
)))
1746 /* If the reference is based on a pointer that points to memory
1747 that may not be written to then the other reference cannot possibly
1749 if ((TREE_CODE (TREE_OPERAND (base2
, 0)) == SSA_NAME
1750 && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base2
, 0)))
1752 && TREE_CODE (TREE_OPERAND (base1
, 0)) == SSA_NAME
1753 && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base1
, 0))))
1756 /* Dispatch to the pointer-vs-decl or pointer-vs-pointer disambiguators. */
1757 if (var1_p
&& ind2_p
)
1758 return indirect_ref_may_alias_decl_p (ref2
->ref
, base2
,
1760 ao_ref_alias_set (ref2
),
1761 ao_ref_base_alias_set (ref2
),
1764 ao_ref_alias_set (ref1
),
1765 ao_ref_base_alias_set (ref1
),
1767 else if (ind1_p
&& ind2_p
)
1768 return indirect_refs_may_alias_p (ref1
->ref
, base1
,
1770 ao_ref_alias_set (ref1
),
1771 ao_ref_base_alias_set (ref1
),
1774 ao_ref_alias_set (ref2
),
1775 ao_ref_base_alias_set (ref2
),
1781 /* Return true, if the two memory references REF1 and REF2 may alias
1782 and update statistics. */
1785 refs_may_alias_p_1 (ao_ref
*ref1
, ao_ref
*ref2
, bool tbaa_p
)
1787 bool res
= refs_may_alias_p_2 (ref1
, ref2
, tbaa_p
);
1789 ++alias_stats
.refs_may_alias_p_may_alias
;
1791 ++alias_stats
.refs_may_alias_p_no_alias
;
1796 refs_may_alias_p (tree ref1
, ao_ref
*ref2
, bool tbaa_p
)
1799 ao_ref_init (&r1
, ref1
);
1800 return refs_may_alias_p_1 (&r1
, ref2
, tbaa_p
);
1804 refs_may_alias_p (tree ref1
, tree ref2
, bool tbaa_p
)
1807 ao_ref_init (&r1
, ref1
);
1808 ao_ref_init (&r2
, ref2
);
1809 return refs_may_alias_p_1 (&r1
, &r2
, tbaa_p
);
1812 /* Returns true if there is a anti-dependence for the STORE that
1813 executes after the LOAD. */
1816 refs_anti_dependent_p (tree load
, tree store
)
1819 ao_ref_init (&r1
, load
);
1820 ao_ref_init (&r2
, store
);
1821 return refs_may_alias_p_1 (&r1
, &r2
, false);
1824 /* Returns true if there is a output dependence for the stores
1825 STORE1 and STORE2. */
1828 refs_output_dependent_p (tree store1
, tree store2
)
1831 ao_ref_init (&r1
, store1
);
1832 ao_ref_init (&r2
, store2
);
1833 return refs_may_alias_p_1 (&r1
, &r2
, false);
1836 /* If the call CALL may use the memory reference REF return true,
1837 otherwise return false. */
1840 ref_maybe_used_by_call_p_1 (gcall
*call
, ao_ref
*ref
, bool tbaa_p
)
1844 int flags
= gimple_call_flags (call
);
1846 /* Const functions without a static chain do not implicitly use memory. */
1847 if (!gimple_call_chain (call
)
1848 && (flags
& (ECF_CONST
|ECF_NOVOPS
)))
1851 base
= ao_ref_base (ref
);
1855 /* A call that is not without side-effects might involve volatile
1856 accesses and thus conflicts with all other volatile accesses. */
1857 if (ref
->volatile_p
)
1860 /* If the reference is based on a decl that is not aliased the call
1861 cannot possibly use it. */
1863 && !may_be_aliased (base
)
1864 /* But local statics can be used through recursion. */
1865 && !is_global_var (base
))
1868 callee
= gimple_call_fndecl (call
);
1870 /* Handle those builtin functions explicitly that do not act as
1871 escape points. See tree-ssa-structalias.c:find_func_aliases
1872 for the list of builtins we might need to handle here. */
1873 if (callee
!= NULL_TREE
1874 && gimple_call_builtin_p (call
, BUILT_IN_NORMAL
))
1875 switch (DECL_FUNCTION_CODE (callee
))
1877 /* All the following functions read memory pointed to by
1878 their second argument. strcat/strncat additionally
1879 reads memory pointed to by the first argument. */
1880 case BUILT_IN_STRCAT
:
1881 case BUILT_IN_STRNCAT
:
1884 ao_ref_init_from_ptr_and_size (&dref
,
1885 gimple_call_arg (call
, 0),
1887 if (refs_may_alias_p_1 (&dref
, ref
, false))
1891 case BUILT_IN_STRCPY
:
1892 case BUILT_IN_STRNCPY
:
1893 case BUILT_IN_MEMCPY
:
1894 case BUILT_IN_MEMMOVE
:
1895 case BUILT_IN_MEMPCPY
:
1896 case BUILT_IN_STPCPY
:
1897 case BUILT_IN_STPNCPY
:
1898 case BUILT_IN_TM_MEMCPY
:
1899 case BUILT_IN_TM_MEMMOVE
:
1902 tree size
= NULL_TREE
;
1903 if (gimple_call_num_args (call
) == 3)
1904 size
= gimple_call_arg (call
, 2);
1905 ao_ref_init_from_ptr_and_size (&dref
,
1906 gimple_call_arg (call
, 1),
1908 return refs_may_alias_p_1 (&dref
, ref
, false);
1910 case BUILT_IN_STRCAT_CHK
:
1911 case BUILT_IN_STRNCAT_CHK
:
1914 ao_ref_init_from_ptr_and_size (&dref
,
1915 gimple_call_arg (call
, 0),
1917 if (refs_may_alias_p_1 (&dref
, ref
, false))
1921 case BUILT_IN_STRCPY_CHK
:
1922 case BUILT_IN_STRNCPY_CHK
:
1923 case BUILT_IN_MEMCPY_CHK
:
1924 case BUILT_IN_MEMMOVE_CHK
:
1925 case BUILT_IN_MEMPCPY_CHK
:
1926 case BUILT_IN_STPCPY_CHK
:
1927 case BUILT_IN_STPNCPY_CHK
:
1930 tree size
= NULL_TREE
;
1931 if (gimple_call_num_args (call
) == 4)
1932 size
= gimple_call_arg (call
, 2);
1933 ao_ref_init_from_ptr_and_size (&dref
,
1934 gimple_call_arg (call
, 1),
1936 return refs_may_alias_p_1 (&dref
, ref
, false);
1938 case BUILT_IN_BCOPY
:
1941 tree size
= gimple_call_arg (call
, 2);
1942 ao_ref_init_from_ptr_and_size (&dref
,
1943 gimple_call_arg (call
, 0),
1945 return refs_may_alias_p_1 (&dref
, ref
, false);
1948 /* The following functions read memory pointed to by their
1950 CASE_BUILT_IN_TM_LOAD (1):
1951 CASE_BUILT_IN_TM_LOAD (2):
1952 CASE_BUILT_IN_TM_LOAD (4):
1953 CASE_BUILT_IN_TM_LOAD (8):
1954 CASE_BUILT_IN_TM_LOAD (FLOAT
):
1955 CASE_BUILT_IN_TM_LOAD (DOUBLE
):
1956 CASE_BUILT_IN_TM_LOAD (LDOUBLE
):
1957 CASE_BUILT_IN_TM_LOAD (M64
):
1958 CASE_BUILT_IN_TM_LOAD (M128
):
1959 CASE_BUILT_IN_TM_LOAD (M256
):
1960 case BUILT_IN_TM_LOG
:
1961 case BUILT_IN_TM_LOG_1
:
1962 case BUILT_IN_TM_LOG_2
:
1963 case BUILT_IN_TM_LOG_4
:
1964 case BUILT_IN_TM_LOG_8
:
1965 case BUILT_IN_TM_LOG_FLOAT
:
1966 case BUILT_IN_TM_LOG_DOUBLE
:
1967 case BUILT_IN_TM_LOG_LDOUBLE
:
1968 case BUILT_IN_TM_LOG_M64
:
1969 case BUILT_IN_TM_LOG_M128
:
1970 case BUILT_IN_TM_LOG_M256
:
1971 return ptr_deref_may_alias_ref_p_1 (gimple_call_arg (call
, 0), ref
);
1973 /* These read memory pointed to by the first argument. */
1974 case BUILT_IN_STRDUP
:
1975 case BUILT_IN_STRNDUP
:
1976 case BUILT_IN_REALLOC
:
1979 tree size
= NULL_TREE
;
1980 if (gimple_call_num_args (call
) == 2)
1981 size
= gimple_call_arg (call
, 1);
1982 ao_ref_init_from_ptr_and_size (&dref
,
1983 gimple_call_arg (call
, 0),
1985 return refs_may_alias_p_1 (&dref
, ref
, false);
1987 /* These read memory pointed to by the first argument. */
1988 case BUILT_IN_INDEX
:
1989 case BUILT_IN_STRCHR
:
1990 case BUILT_IN_STRRCHR
:
1993 ao_ref_init_from_ptr_and_size (&dref
,
1994 gimple_call_arg (call
, 0),
1996 return refs_may_alias_p_1 (&dref
, ref
, false);
1998 /* These read memory pointed to by the first argument with size
1999 in the third argument. */
2000 case BUILT_IN_MEMCHR
:
2003 ao_ref_init_from_ptr_and_size (&dref
,
2004 gimple_call_arg (call
, 0),
2005 gimple_call_arg (call
, 2));
2006 return refs_may_alias_p_1 (&dref
, ref
, false);
2008 /* These read memory pointed to by the first and second arguments. */
2009 case BUILT_IN_STRSTR
:
2010 case BUILT_IN_STRPBRK
:
2013 ao_ref_init_from_ptr_and_size (&dref
,
2014 gimple_call_arg (call
, 0),
2016 if (refs_may_alias_p_1 (&dref
, ref
, false))
2018 ao_ref_init_from_ptr_and_size (&dref
,
2019 gimple_call_arg (call
, 1),
2021 return refs_may_alias_p_1 (&dref
, ref
, false);
2024 /* The following builtins do not read from memory. */
2026 case BUILT_IN_MALLOC
:
2027 case BUILT_IN_POSIX_MEMALIGN
:
2028 case BUILT_IN_ALIGNED_ALLOC
:
2029 case BUILT_IN_CALLOC
:
2030 CASE_BUILT_IN_ALLOCA
:
2031 case BUILT_IN_STACK_SAVE
:
2032 case BUILT_IN_STACK_RESTORE
:
2033 case BUILT_IN_MEMSET
:
2034 case BUILT_IN_TM_MEMSET
:
2035 case BUILT_IN_MEMSET_CHK
:
2036 case BUILT_IN_FREXP
:
2037 case BUILT_IN_FREXPF
:
2038 case BUILT_IN_FREXPL
:
2039 case BUILT_IN_GAMMA_R
:
2040 case BUILT_IN_GAMMAF_R
:
2041 case BUILT_IN_GAMMAL_R
:
2042 case BUILT_IN_LGAMMA_R
:
2043 case BUILT_IN_LGAMMAF_R
:
2044 case BUILT_IN_LGAMMAL_R
:
2046 case BUILT_IN_MODFF
:
2047 case BUILT_IN_MODFL
:
2048 case BUILT_IN_REMQUO
:
2049 case BUILT_IN_REMQUOF
:
2050 case BUILT_IN_REMQUOL
:
2051 case BUILT_IN_SINCOS
:
2052 case BUILT_IN_SINCOSF
:
2053 case BUILT_IN_SINCOSL
:
2054 case BUILT_IN_ASSUME_ALIGNED
:
2055 case BUILT_IN_VA_END
:
2057 /* __sync_* builtins and some OpenMP builtins act as threading
2059 #undef DEF_SYNC_BUILTIN
2060 #define DEF_SYNC_BUILTIN(ENUM, NAME, TYPE, ATTRS) case ENUM:
2061 #include "sync-builtins.def"
2062 #undef DEF_SYNC_BUILTIN
2063 case BUILT_IN_GOMP_ATOMIC_START
:
2064 case BUILT_IN_GOMP_ATOMIC_END
:
2065 case BUILT_IN_GOMP_BARRIER
:
2066 case BUILT_IN_GOMP_BARRIER_CANCEL
:
2067 case BUILT_IN_GOMP_TASKWAIT
:
2068 case BUILT_IN_GOMP_TASKGROUP_END
:
2069 case BUILT_IN_GOMP_CRITICAL_START
:
2070 case BUILT_IN_GOMP_CRITICAL_END
:
2071 case BUILT_IN_GOMP_CRITICAL_NAME_START
:
2072 case BUILT_IN_GOMP_CRITICAL_NAME_END
:
2073 case BUILT_IN_GOMP_LOOP_END
:
2074 case BUILT_IN_GOMP_LOOP_END_CANCEL
:
2075 case BUILT_IN_GOMP_ORDERED_START
:
2076 case BUILT_IN_GOMP_ORDERED_END
:
2077 case BUILT_IN_GOMP_SECTIONS_END
:
2078 case BUILT_IN_GOMP_SECTIONS_END_CANCEL
:
2079 case BUILT_IN_GOMP_SINGLE_COPY_START
:
2080 case BUILT_IN_GOMP_SINGLE_COPY_END
:
2084 /* Fallthru to general call handling. */;
2087 /* Check if base is a global static variable that is not read
2089 if (callee
!= NULL_TREE
&& VAR_P (base
) && TREE_STATIC (base
))
2091 struct cgraph_node
*node
= cgraph_node::get (callee
);
2094 /* FIXME: Callee can be an OMP builtin that does not have a call graph
2095 node yet. We should enforce that there are nodes for all decls in the
2096 IL and remove this check instead. */
2098 && (not_read
= ipa_reference_get_not_read_global (node
))
2099 && bitmap_bit_p (not_read
, ipa_reference_var_uid (base
)))
2103 /* Check if the base variable is call-used. */
2106 if (pt_solution_includes (gimple_call_use_set (call
), base
))
2109 else if ((TREE_CODE (base
) == MEM_REF
2110 || TREE_CODE (base
) == TARGET_MEM_REF
)
2111 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
)
2113 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (TREE_OPERAND (base
, 0));
2117 if (pt_solutions_intersect (gimple_call_use_set (call
), &pi
->pt
))
2123 /* Inspect call arguments for passed-by-value aliases. */
2125 for (i
= 0; i
< gimple_call_num_args (call
); ++i
)
2127 tree op
= gimple_call_arg (call
, i
);
2128 int flags
= gimple_call_arg_flags (call
, i
);
2130 if (flags
& EAF_UNUSED
)
2133 if (TREE_CODE (op
) == WITH_SIZE_EXPR
)
2134 op
= TREE_OPERAND (op
, 0);
2136 if (TREE_CODE (op
) != SSA_NAME
2137 && !is_gimple_min_invariant (op
))
2140 ao_ref_init (&r
, op
);
2141 if (refs_may_alias_p_1 (&r
, ref
, tbaa_p
))
2150 ref_maybe_used_by_call_p (gcall
*call
, ao_ref
*ref
, bool tbaa_p
)
2153 res
= ref_maybe_used_by_call_p_1 (call
, ref
, tbaa_p
);
2155 ++alias_stats
.ref_maybe_used_by_call_p_may_alias
;
2157 ++alias_stats
.ref_maybe_used_by_call_p_no_alias
;
2162 /* If the statement STMT may use the memory reference REF return
2163 true, otherwise return false. */
2166 ref_maybe_used_by_stmt_p (gimple
*stmt
, ao_ref
*ref
, bool tbaa_p
)
2168 if (is_gimple_assign (stmt
))
2172 /* All memory assign statements are single. */
2173 if (!gimple_assign_single_p (stmt
))
2176 rhs
= gimple_assign_rhs1 (stmt
);
2177 if (is_gimple_reg (rhs
)
2178 || is_gimple_min_invariant (rhs
)
2179 || gimple_assign_rhs_code (stmt
) == CONSTRUCTOR
)
2182 return refs_may_alias_p (rhs
, ref
, tbaa_p
);
2184 else if (is_gimple_call (stmt
))
2185 return ref_maybe_used_by_call_p (as_a
<gcall
*> (stmt
), ref
, tbaa_p
);
2186 else if (greturn
*return_stmt
= dyn_cast
<greturn
*> (stmt
))
2188 tree retval
= gimple_return_retval (return_stmt
);
2190 && TREE_CODE (retval
) != SSA_NAME
2191 && !is_gimple_min_invariant (retval
)
2192 && refs_may_alias_p (retval
, ref
, tbaa_p
))
2194 /* If ref escapes the function then the return acts as a use. */
2195 tree base
= ao_ref_base (ref
);
2198 else if (DECL_P (base
))
2199 return is_global_var (base
);
2200 else if (TREE_CODE (base
) == MEM_REF
2201 || TREE_CODE (base
) == TARGET_MEM_REF
)
2202 return ptr_deref_may_alias_global_p (TREE_OPERAND (base
, 0));
2210 ref_maybe_used_by_stmt_p (gimple
*stmt
, tree ref
, bool tbaa_p
)
2213 ao_ref_init (&r
, ref
);
2214 return ref_maybe_used_by_stmt_p (stmt
, &r
, tbaa_p
);
2217 /* If the call in statement CALL may clobber the memory reference REF
2218 return true, otherwise return false. */
2221 call_may_clobber_ref_p_1 (gcall
*call
, ao_ref
*ref
)
2226 /* If the call is pure or const it cannot clobber anything. */
2227 if (gimple_call_flags (call
)
2228 & (ECF_PURE
|ECF_CONST
|ECF_LOOPING_CONST_OR_PURE
|ECF_NOVOPS
))
2230 if (gimple_call_internal_p (call
))
2231 switch (gimple_call_internal_fn (call
))
2233 /* Treat these internal calls like ECF_PURE for aliasing,
2234 they don't write to any memory the program should care about.
2235 They have important other side-effects, and read memory,
2236 so can't be ECF_NOVOPS. */
2237 case IFN_UBSAN_NULL
:
2238 case IFN_UBSAN_BOUNDS
:
2239 case IFN_UBSAN_VPTR
:
2240 case IFN_UBSAN_OBJECT_SIZE
:
2242 case IFN_ASAN_CHECK
:
2248 base
= ao_ref_base (ref
);
2252 if (TREE_CODE (base
) == SSA_NAME
2253 || CONSTANT_CLASS_P (base
))
2256 /* A call that is not without side-effects might involve volatile
2257 accesses and thus conflicts with all other volatile accesses. */
2258 if (ref
->volatile_p
)
2261 /* If the reference is based on a decl that is not aliased the call
2262 cannot possibly clobber it. */
2264 && !may_be_aliased (base
)
2265 /* But local non-readonly statics can be modified through recursion
2266 or the call may implement a threading barrier which we must
2267 treat as may-def. */
2268 && (TREE_READONLY (base
)
2269 || !is_global_var (base
)))
2272 /* If the reference is based on a pointer that points to memory
2273 that may not be written to then the call cannot possibly clobber it. */
2274 if ((TREE_CODE (base
) == MEM_REF
2275 || TREE_CODE (base
) == TARGET_MEM_REF
)
2276 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
2277 && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base
, 0)))
2280 callee
= gimple_call_fndecl (call
);
2282 /* Handle those builtin functions explicitly that do not act as
2283 escape points. See tree-ssa-structalias.c:find_func_aliases
2284 for the list of builtins we might need to handle here. */
2285 if (callee
!= NULL_TREE
2286 && gimple_call_builtin_p (call
, BUILT_IN_NORMAL
))
2287 switch (DECL_FUNCTION_CODE (callee
))
2289 /* All the following functions clobber memory pointed to by
2290 their first argument. */
2291 case BUILT_IN_STRCPY
:
2292 case BUILT_IN_STRNCPY
:
2293 case BUILT_IN_MEMCPY
:
2294 case BUILT_IN_MEMMOVE
:
2295 case BUILT_IN_MEMPCPY
:
2296 case BUILT_IN_STPCPY
:
2297 case BUILT_IN_STPNCPY
:
2298 case BUILT_IN_STRCAT
:
2299 case BUILT_IN_STRNCAT
:
2300 case BUILT_IN_MEMSET
:
2301 case BUILT_IN_TM_MEMSET
:
2302 CASE_BUILT_IN_TM_STORE (1):
2303 CASE_BUILT_IN_TM_STORE (2):
2304 CASE_BUILT_IN_TM_STORE (4):
2305 CASE_BUILT_IN_TM_STORE (8):
2306 CASE_BUILT_IN_TM_STORE (FLOAT
):
2307 CASE_BUILT_IN_TM_STORE (DOUBLE
):
2308 CASE_BUILT_IN_TM_STORE (LDOUBLE
):
2309 CASE_BUILT_IN_TM_STORE (M64
):
2310 CASE_BUILT_IN_TM_STORE (M128
):
2311 CASE_BUILT_IN_TM_STORE (M256
):
2312 case BUILT_IN_TM_MEMCPY
:
2313 case BUILT_IN_TM_MEMMOVE
:
2316 tree size
= NULL_TREE
;
2317 /* Don't pass in size for strncat, as the maximum size
2318 is strlen (dest) + n + 1 instead of n, resp.
2319 n + 1 at dest + strlen (dest), but strlen (dest) isn't
2321 if (gimple_call_num_args (call
) == 3
2322 && DECL_FUNCTION_CODE (callee
) != BUILT_IN_STRNCAT
)
2323 size
= gimple_call_arg (call
, 2);
2324 ao_ref_init_from_ptr_and_size (&dref
,
2325 gimple_call_arg (call
, 0),
2327 return refs_may_alias_p_1 (&dref
, ref
, false);
2329 case BUILT_IN_STRCPY_CHK
:
2330 case BUILT_IN_STRNCPY_CHK
:
2331 case BUILT_IN_MEMCPY_CHK
:
2332 case BUILT_IN_MEMMOVE_CHK
:
2333 case BUILT_IN_MEMPCPY_CHK
:
2334 case BUILT_IN_STPCPY_CHK
:
2335 case BUILT_IN_STPNCPY_CHK
:
2336 case BUILT_IN_STRCAT_CHK
:
2337 case BUILT_IN_STRNCAT_CHK
:
2338 case BUILT_IN_MEMSET_CHK
:
2341 tree size
= NULL_TREE
;
2342 /* Don't pass in size for __strncat_chk, as the maximum size
2343 is strlen (dest) + n + 1 instead of n, resp.
2344 n + 1 at dest + strlen (dest), but strlen (dest) isn't
2346 if (gimple_call_num_args (call
) == 4
2347 && DECL_FUNCTION_CODE (callee
) != BUILT_IN_STRNCAT_CHK
)
2348 size
= gimple_call_arg (call
, 2);
2349 ao_ref_init_from_ptr_and_size (&dref
,
2350 gimple_call_arg (call
, 0),
2352 return refs_may_alias_p_1 (&dref
, ref
, false);
2354 case BUILT_IN_BCOPY
:
2357 tree size
= gimple_call_arg (call
, 2);
2358 ao_ref_init_from_ptr_and_size (&dref
,
2359 gimple_call_arg (call
, 1),
2361 return refs_may_alias_p_1 (&dref
, ref
, false);
2363 /* Allocating memory does not have any side-effects apart from
2364 being the definition point for the pointer. */
2365 case BUILT_IN_MALLOC
:
2366 case BUILT_IN_ALIGNED_ALLOC
:
2367 case BUILT_IN_CALLOC
:
2368 case BUILT_IN_STRDUP
:
2369 case BUILT_IN_STRNDUP
:
2370 /* Unix98 specifies that errno is set on allocation failure. */
2372 && targetm
.ref_may_alias_errno (ref
))
2375 case BUILT_IN_STACK_SAVE
:
2376 CASE_BUILT_IN_ALLOCA
:
2377 case BUILT_IN_ASSUME_ALIGNED
:
2379 /* But posix_memalign stores a pointer into the memory pointed to
2380 by its first argument. */
2381 case BUILT_IN_POSIX_MEMALIGN
:
2383 tree ptrptr
= gimple_call_arg (call
, 0);
2385 ao_ref_init_from_ptr_and_size (&dref
, ptrptr
,
2386 TYPE_SIZE_UNIT (ptr_type_node
));
2387 return (refs_may_alias_p_1 (&dref
, ref
, false)
2389 && targetm
.ref_may_alias_errno (ref
)));
2391 /* Freeing memory kills the pointed-to memory. More importantly
2392 the call has to serve as a barrier for moving loads and stores
2395 case BUILT_IN_VA_END
:
2397 tree ptr
= gimple_call_arg (call
, 0);
2398 return ptr_deref_may_alias_ref_p_1 (ptr
, ref
);
2400 /* Realloc serves both as allocation point and deallocation point. */
2401 case BUILT_IN_REALLOC
:
2403 tree ptr
= gimple_call_arg (call
, 0);
2404 /* Unix98 specifies that errno is set on allocation failure. */
2405 return ((flag_errno_math
2406 && targetm
.ref_may_alias_errno (ref
))
2407 || ptr_deref_may_alias_ref_p_1 (ptr
, ref
));
2409 case BUILT_IN_GAMMA_R
:
2410 case BUILT_IN_GAMMAF_R
:
2411 case BUILT_IN_GAMMAL_R
:
2412 case BUILT_IN_LGAMMA_R
:
2413 case BUILT_IN_LGAMMAF_R
:
2414 case BUILT_IN_LGAMMAL_R
:
2416 tree out
= gimple_call_arg (call
, 1);
2417 if (ptr_deref_may_alias_ref_p_1 (out
, ref
))
2419 if (flag_errno_math
)
2423 case BUILT_IN_FREXP
:
2424 case BUILT_IN_FREXPF
:
2425 case BUILT_IN_FREXPL
:
2427 case BUILT_IN_MODFF
:
2428 case BUILT_IN_MODFL
:
2430 tree out
= gimple_call_arg (call
, 1);
2431 return ptr_deref_may_alias_ref_p_1 (out
, ref
);
2433 case BUILT_IN_REMQUO
:
2434 case BUILT_IN_REMQUOF
:
2435 case BUILT_IN_REMQUOL
:
2437 tree out
= gimple_call_arg (call
, 2);
2438 if (ptr_deref_may_alias_ref_p_1 (out
, ref
))
2440 if (flag_errno_math
)
2444 case BUILT_IN_SINCOS
:
2445 case BUILT_IN_SINCOSF
:
2446 case BUILT_IN_SINCOSL
:
2448 tree sin
= gimple_call_arg (call
, 1);
2449 tree cos
= gimple_call_arg (call
, 2);
2450 return (ptr_deref_may_alias_ref_p_1 (sin
, ref
)
2451 || ptr_deref_may_alias_ref_p_1 (cos
, ref
));
2453 /* __sync_* builtins and some OpenMP builtins act as threading
2455 #undef DEF_SYNC_BUILTIN
2456 #define DEF_SYNC_BUILTIN(ENUM, NAME, TYPE, ATTRS) case ENUM:
2457 #include "sync-builtins.def"
2458 #undef DEF_SYNC_BUILTIN
2459 case BUILT_IN_GOMP_ATOMIC_START
:
2460 case BUILT_IN_GOMP_ATOMIC_END
:
2461 case BUILT_IN_GOMP_BARRIER
:
2462 case BUILT_IN_GOMP_BARRIER_CANCEL
:
2463 case BUILT_IN_GOMP_TASKWAIT
:
2464 case BUILT_IN_GOMP_TASKGROUP_END
:
2465 case BUILT_IN_GOMP_CRITICAL_START
:
2466 case BUILT_IN_GOMP_CRITICAL_END
:
2467 case BUILT_IN_GOMP_CRITICAL_NAME_START
:
2468 case BUILT_IN_GOMP_CRITICAL_NAME_END
:
2469 case BUILT_IN_GOMP_LOOP_END
:
2470 case BUILT_IN_GOMP_LOOP_END_CANCEL
:
2471 case BUILT_IN_GOMP_ORDERED_START
:
2472 case BUILT_IN_GOMP_ORDERED_END
:
2473 case BUILT_IN_GOMP_SECTIONS_END
:
2474 case BUILT_IN_GOMP_SECTIONS_END_CANCEL
:
2475 case BUILT_IN_GOMP_SINGLE_COPY_START
:
2476 case BUILT_IN_GOMP_SINGLE_COPY_END
:
2479 /* Fallthru to general call handling. */;
2482 /* Check if base is a global static variable that is not written
2484 if (callee
!= NULL_TREE
&& VAR_P (base
) && TREE_STATIC (base
))
2486 struct cgraph_node
*node
= cgraph_node::get (callee
);
2490 && (not_written
= ipa_reference_get_not_written_global (node
))
2491 && bitmap_bit_p (not_written
, ipa_reference_var_uid (base
)))
2495 /* Check if the base variable is call-clobbered. */
2497 return pt_solution_includes (gimple_call_clobber_set (call
), base
);
2498 else if ((TREE_CODE (base
) == MEM_REF
2499 || TREE_CODE (base
) == TARGET_MEM_REF
)
2500 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
)
2502 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (TREE_OPERAND (base
, 0));
2506 return pt_solutions_intersect (gimple_call_clobber_set (call
), &pi
->pt
);
2512 /* If the call in statement CALL may clobber the memory reference REF
2513 return true, otherwise return false. */
2516 call_may_clobber_ref_p (gcall
*call
, tree ref
)
2520 ao_ref_init (&r
, ref
);
2521 res
= call_may_clobber_ref_p_1 (call
, &r
);
2523 ++alias_stats
.call_may_clobber_ref_p_may_alias
;
2525 ++alias_stats
.call_may_clobber_ref_p_no_alias
;
2530 /* If the statement STMT may clobber the memory reference REF return true,
2531 otherwise return false. */
2534 stmt_may_clobber_ref_p_1 (gimple
*stmt
, ao_ref
*ref
, bool tbaa_p
)
2536 if (is_gimple_call (stmt
))
2538 tree lhs
= gimple_call_lhs (stmt
);
2540 && TREE_CODE (lhs
) != SSA_NAME
)
2543 ao_ref_init (&r
, lhs
);
2544 if (refs_may_alias_p_1 (ref
, &r
, tbaa_p
))
2548 return call_may_clobber_ref_p_1 (as_a
<gcall
*> (stmt
), ref
);
2550 else if (gimple_assign_single_p (stmt
))
2552 tree lhs
= gimple_assign_lhs (stmt
);
2553 if (TREE_CODE (lhs
) != SSA_NAME
)
2556 ao_ref_init (&r
, lhs
);
2557 return refs_may_alias_p_1 (ref
, &r
, tbaa_p
);
2560 else if (gimple_code (stmt
) == GIMPLE_ASM
)
2567 stmt_may_clobber_ref_p (gimple
*stmt
, tree ref
, bool tbaa_p
)
2570 ao_ref_init (&r
, ref
);
2571 return stmt_may_clobber_ref_p_1 (stmt
, &r
, tbaa_p
);
2574 /* Return true if store1 and store2 described by corresponding tuples
2575 <BASE, OFFSET, SIZE, MAX_SIZE> have the same size and store to the same
2579 same_addr_size_stores_p (tree base1
, poly_int64 offset1
, poly_int64 size1
,
2580 poly_int64 max_size1
,
2581 tree base2
, poly_int64 offset2
, poly_int64 size2
,
2582 poly_int64 max_size2
)
2584 /* Offsets need to be 0. */
2585 if (maybe_ne (offset1
, 0)
2586 || maybe_ne (offset2
, 0))
2589 bool base1_obj_p
= SSA_VAR_P (base1
);
2590 bool base2_obj_p
= SSA_VAR_P (base2
);
2592 /* We need one object. */
2593 if (base1_obj_p
== base2_obj_p
)
2595 tree obj
= base1_obj_p
? base1
: base2
;
2597 /* And we need one MEM_REF. */
2598 bool base1_memref_p
= TREE_CODE (base1
) == MEM_REF
;
2599 bool base2_memref_p
= TREE_CODE (base2
) == MEM_REF
;
2600 if (base1_memref_p
== base2_memref_p
)
2602 tree memref
= base1_memref_p
? base1
: base2
;
2604 /* Sizes need to be valid. */
2605 if (!known_size_p (max_size1
)
2606 || !known_size_p (max_size2
)
2607 || !known_size_p (size1
)
2608 || !known_size_p (size2
))
2611 /* Max_size needs to match size. */
2612 if (maybe_ne (max_size1
, size1
)
2613 || maybe_ne (max_size2
, size2
))
2616 /* Sizes need to match. */
2617 if (maybe_ne (size1
, size2
))
2621 /* Check that memref is a store to pointer with singleton points-to info. */
2622 if (!integer_zerop (TREE_OPERAND (memref
, 1)))
2624 tree ptr
= TREE_OPERAND (memref
, 0);
2625 if (TREE_CODE (ptr
) != SSA_NAME
)
2627 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (ptr
);
2628 unsigned int pt_uid
;
2630 || !pt_solution_singleton_or_null_p (&pi
->pt
, &pt_uid
))
2633 /* Be conservative with non-call exceptions when the address might
2635 if (cfun
->can_throw_non_call_exceptions
&& pi
->pt
.null
)
2638 /* Check that ptr points relative to obj. */
2639 unsigned int obj_uid
= DECL_PT_UID (obj
);
2640 if (obj_uid
!= pt_uid
)
2643 /* Check that the object size is the same as the store size. That ensures us
2644 that ptr points to the start of obj. */
2645 return (DECL_SIZE (obj
)
2646 && poly_int_tree_p (DECL_SIZE (obj
))
2647 && known_eq (wi::to_poly_offset (DECL_SIZE (obj
)), size1
));
2650 /* If STMT kills the memory reference REF return true, otherwise
2654 stmt_kills_ref_p (gimple
*stmt
, ao_ref
*ref
)
2656 if (!ao_ref_base (ref
))
2659 if (gimple_has_lhs (stmt
)
2660 && TREE_CODE (gimple_get_lhs (stmt
)) != SSA_NAME
2661 /* The assignment is not necessarily carried out if it can throw
2662 and we can catch it in the current function where we could inspect
2664 ??? We only need to care about the RHS throwing. For aggregate
2665 assignments or similar calls and non-call exceptions the LHS
2666 might throw as well. */
2667 && !stmt_can_throw_internal (cfun
, stmt
))
2669 tree lhs
= gimple_get_lhs (stmt
);
2670 /* If LHS is literally a base of the access we are done. */
2673 tree base
= ref
->ref
;
2674 tree innermost_dropped_array_ref
= NULL_TREE
;
2675 if (handled_component_p (base
))
2677 tree saved_lhs0
= NULL_TREE
;
2678 if (handled_component_p (lhs
))
2680 saved_lhs0
= TREE_OPERAND (lhs
, 0);
2681 TREE_OPERAND (lhs
, 0) = integer_zero_node
;
2685 /* Just compare the outermost handled component, if
2686 they are equal we have found a possible common
2688 tree saved_base0
= TREE_OPERAND (base
, 0);
2689 TREE_OPERAND (base
, 0) = integer_zero_node
;
2690 bool res
= operand_equal_p (lhs
, base
, 0);
2691 TREE_OPERAND (base
, 0) = saved_base0
;
2694 /* Remember if we drop an array-ref that we need to
2695 double-check not being at struct end. */
2696 if (TREE_CODE (base
) == ARRAY_REF
2697 || TREE_CODE (base
) == ARRAY_RANGE_REF
)
2698 innermost_dropped_array_ref
= base
;
2699 /* Otherwise drop handled components of the access. */
2702 while (handled_component_p (base
));
2704 TREE_OPERAND (lhs
, 0) = saved_lhs0
;
2706 /* Finally check if the lhs has the same address and size as the
2707 base candidate of the access. Watch out if we have dropped
2708 an array-ref that was at struct end, this means ref->ref may
2709 be outside of the TYPE_SIZE of its base. */
2710 if ((! innermost_dropped_array_ref
2711 || ! array_at_struct_end_p (innermost_dropped_array_ref
))
2713 || (((TYPE_SIZE (TREE_TYPE (lhs
))
2714 == TYPE_SIZE (TREE_TYPE (base
)))
2715 || (TYPE_SIZE (TREE_TYPE (lhs
))
2716 && TYPE_SIZE (TREE_TYPE (base
))
2717 && operand_equal_p (TYPE_SIZE (TREE_TYPE (lhs
)),
2718 TYPE_SIZE (TREE_TYPE (base
)),
2720 && operand_equal_p (lhs
, base
,
2722 | OEP_MATCH_SIDE_EFFECTS
))))
2726 /* Now look for non-literal equal bases with the restriction of
2727 handling constant offset and size. */
2728 /* For a must-alias check we need to be able to constrain
2729 the access properly. */
2730 if (!ref
->max_size_known_p ())
2732 poly_int64 size
, offset
, max_size
, ref_offset
= ref
->offset
;
2734 tree base
= get_ref_base_and_extent (lhs
, &offset
, &size
, &max_size
,
2736 /* We can get MEM[symbol: sZ, index: D.8862_1] here,
2737 so base == ref->base does not always hold. */
2738 if (base
!= ref
->base
)
2740 /* Try using points-to info. */
2741 if (same_addr_size_stores_p (base
, offset
, size
, max_size
, ref
->base
,
2742 ref
->offset
, ref
->size
, ref
->max_size
))
2745 /* If both base and ref->base are MEM_REFs, only compare the
2746 first operand, and if the second operand isn't equal constant,
2747 try to add the offsets into offset and ref_offset. */
2748 if (TREE_CODE (base
) == MEM_REF
&& TREE_CODE (ref
->base
) == MEM_REF
2749 && TREE_OPERAND (base
, 0) == TREE_OPERAND (ref
->base
, 0))
2751 if (!tree_int_cst_equal (TREE_OPERAND (base
, 1),
2752 TREE_OPERAND (ref
->base
, 1)))
2754 poly_offset_int off1
= mem_ref_offset (base
);
2755 off1
<<= LOG2_BITS_PER_UNIT
;
2757 poly_offset_int off2
= mem_ref_offset (ref
->base
);
2758 off2
<<= LOG2_BITS_PER_UNIT
;
2760 if (!off1
.to_shwi (&offset
) || !off2
.to_shwi (&ref_offset
))
2767 /* For a must-alias check we need to be able to constrain
2768 the access properly. */
2769 if (known_eq (size
, max_size
)
2770 && known_subrange_p (ref_offset
, ref
->max_size
, offset
, size
))
2774 if (is_gimple_call (stmt
))
2776 tree callee
= gimple_call_fndecl (stmt
);
2777 if (callee
!= NULL_TREE
2778 && gimple_call_builtin_p (stmt
, BUILT_IN_NORMAL
))
2779 switch (DECL_FUNCTION_CODE (callee
))
2783 tree ptr
= gimple_call_arg (stmt
, 0);
2784 tree base
= ao_ref_base (ref
);
2785 if (base
&& TREE_CODE (base
) == MEM_REF
2786 && TREE_OPERAND (base
, 0) == ptr
)
2791 case BUILT_IN_MEMCPY
:
2792 case BUILT_IN_MEMPCPY
:
2793 case BUILT_IN_MEMMOVE
:
2794 case BUILT_IN_MEMSET
:
2795 case BUILT_IN_MEMCPY_CHK
:
2796 case BUILT_IN_MEMPCPY_CHK
:
2797 case BUILT_IN_MEMMOVE_CHK
:
2798 case BUILT_IN_MEMSET_CHK
:
2799 case BUILT_IN_STRNCPY
:
2800 case BUILT_IN_STPNCPY
:
2802 /* For a must-alias check we need to be able to constrain
2803 the access properly. */
2804 if (!ref
->max_size_known_p ())
2806 tree dest
= gimple_call_arg (stmt
, 0);
2807 tree len
= gimple_call_arg (stmt
, 2);
2808 if (!poly_int_tree_p (len
))
2810 tree rbase
= ref
->base
;
2811 poly_offset_int roffset
= ref
->offset
;
2813 ao_ref_init_from_ptr_and_size (&dref
, dest
, len
);
2814 tree base
= ao_ref_base (&dref
);
2815 poly_offset_int offset
= dref
.offset
;
2816 if (!base
|| !known_size_p (dref
.size
))
2818 if (TREE_CODE (base
) == MEM_REF
)
2820 if (TREE_CODE (rbase
) != MEM_REF
)
2822 // Compare pointers.
2823 offset
+= mem_ref_offset (base
) << LOG2_BITS_PER_UNIT
;
2824 roffset
+= mem_ref_offset (rbase
) << LOG2_BITS_PER_UNIT
;
2825 base
= TREE_OPERAND (base
, 0);
2826 rbase
= TREE_OPERAND (rbase
, 0);
2829 && known_subrange_p (roffset
, ref
->max_size
, offset
,
2830 wi::to_poly_offset (len
)
2831 << LOG2_BITS_PER_UNIT
))
2836 case BUILT_IN_VA_END
:
2838 tree ptr
= gimple_call_arg (stmt
, 0);
2839 if (TREE_CODE (ptr
) == ADDR_EXPR
)
2841 tree base
= ao_ref_base (ref
);
2842 if (TREE_OPERAND (ptr
, 0) == base
)
2855 stmt_kills_ref_p (gimple
*stmt
, tree ref
)
2858 ao_ref_init (&r
, ref
);
2859 return stmt_kills_ref_p (stmt
, &r
);
2863 /* Walk the virtual use-def chain of VUSE until hitting the virtual operand
2864 TARGET or a statement clobbering the memory reference REF in which
2865 case false is returned. The walk starts with VUSE, one argument of PHI. */
2868 maybe_skip_until (gimple
*phi
, tree
&target
, basic_block target_bb
,
2869 ao_ref
*ref
, tree vuse
, unsigned int &limit
, bitmap
*visited
,
2870 bool abort_on_visited
,
2871 void *(*translate
)(ao_ref
*, tree
, void *, bool *),
2874 basic_block bb
= gimple_bb (phi
);
2877 *visited
= BITMAP_ALLOC (NULL
);
2879 bitmap_set_bit (*visited
, SSA_NAME_VERSION (PHI_RESULT (phi
)));
2881 /* Walk until we hit the target. */
2882 while (vuse
!= target
)
2884 gimple
*def_stmt
= SSA_NAME_DEF_STMT (vuse
);
2885 /* If we are searching for the target VUSE by walking up to
2886 TARGET_BB dominating the original PHI we are finished once
2887 we reach a default def or a definition in a block dominating
2888 that block. Update TARGET and return. */
2890 && (gimple_nop_p (def_stmt
)
2891 || dominated_by_p (CDI_DOMINATORS
,
2892 target_bb
, gimple_bb (def_stmt
))))
2898 /* Recurse for PHI nodes. */
2899 if (gimple_code (def_stmt
) == GIMPLE_PHI
)
2901 /* An already visited PHI node ends the walk successfully. */
2902 if (bitmap_bit_p (*visited
, SSA_NAME_VERSION (PHI_RESULT (def_stmt
))))
2903 return !abort_on_visited
;
2904 vuse
= get_continuation_for_phi (def_stmt
, ref
, limit
,
2905 visited
, abort_on_visited
,
2911 else if (gimple_nop_p (def_stmt
))
2915 /* A clobbering statement or the end of the IL ends it failing. */
2916 if ((int)limit
<= 0)
2919 if (stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
2921 bool disambiguate_only
= true;
2923 && (*translate
) (ref
, vuse
, data
, &disambiguate_only
) == NULL
)
2929 /* If we reach a new basic-block see if we already skipped it
2930 in a previous walk that ended successfully. */
2931 if (gimple_bb (def_stmt
) != bb
)
2933 if (!bitmap_set_bit (*visited
, SSA_NAME_VERSION (vuse
)))
2934 return !abort_on_visited
;
2935 bb
= gimple_bb (def_stmt
);
2937 vuse
= gimple_vuse (def_stmt
);
2943 /* Starting from a PHI node for the virtual operand of the memory reference
2944 REF find a continuation virtual operand that allows to continue walking
2945 statements dominating PHI skipping only statements that cannot possibly
2946 clobber REF. Decrements LIMIT for each alias disambiguation done
2947 and aborts the walk, returning NULL_TREE if it reaches zero.
2948 Returns NULL_TREE if no suitable virtual operand can be found. */
2951 get_continuation_for_phi (gimple
*phi
, ao_ref
*ref
,
2952 unsigned int &limit
, bitmap
*visited
,
2953 bool abort_on_visited
,
2954 void *(*translate
)(ao_ref
*, tree
, void *, bool *),
2957 unsigned nargs
= gimple_phi_num_args (phi
);
2959 /* Through a single-argument PHI we can simply look through. */
2961 return PHI_ARG_DEF (phi
, 0);
2963 /* For two or more arguments try to pairwise skip non-aliasing code
2964 until we hit the phi argument definition that dominates the other one. */
2965 basic_block phi_bb
= gimple_bb (phi
);
2969 /* Find a candidate for the virtual operand which definition
2970 dominates those of all others. */
2971 /* First look if any of the args themselves satisfy this. */
2972 for (i
= 0; i
< nargs
; ++i
)
2974 arg0
= PHI_ARG_DEF (phi
, i
);
2975 if (SSA_NAME_IS_DEFAULT_DEF (arg0
))
2977 basic_block def_bb
= gimple_bb (SSA_NAME_DEF_STMT (arg0
));
2978 if (def_bb
!= phi_bb
2979 && dominated_by_p (CDI_DOMINATORS
, phi_bb
, def_bb
))
2983 /* If not, look if we can reach such candidate by walking defs
2984 until we hit the immediate dominator. maybe_skip_until will
2986 basic_block dom
= get_immediate_dominator (CDI_DOMINATORS
, phi_bb
);
2988 /* Then check against the (to be) found candidate. */
2989 for (i
= 0; i
< nargs
; ++i
)
2991 arg1
= PHI_ARG_DEF (phi
, i
);
2994 else if (! maybe_skip_until (phi
, arg0
, dom
, ref
, arg1
, limit
, visited
,
2996 /* Do not translate when walking over
3000 gimple_bb (SSA_NAME_DEF_STMT (arg1
)),
3002 ? NULL
: translate
, data
))
3009 /* Based on the memory reference REF and its virtual use VUSE call
3010 WALKER for each virtual use that is equivalent to VUSE, including VUSE
3011 itself. That is, for each virtual use for which its defining statement
3012 does not clobber REF.
3014 WALKER is called with REF, the current virtual use and DATA. If
3015 WALKER returns non-NULL the walk stops and its result is returned.
3016 At the end of a non-successful walk NULL is returned.
3018 TRANSLATE if non-NULL is called with a pointer to REF, the virtual
3019 use which definition is a statement that may clobber REF and DATA.
3020 If TRANSLATE returns (void *)-1 the walk stops and NULL is returned.
3021 If TRANSLATE returns non-NULL the walk stops and its result is returned.
3022 If TRANSLATE returns NULL the walk continues and TRANSLATE is supposed
3023 to adjust REF and *DATA to make that valid.
3025 VALUEIZE if non-NULL is called with the next VUSE that is considered
3026 and return value is substituted for that. This can be used to
3027 implement optimistic value-numbering for example. Note that the
3028 VUSE argument is assumed to be valueized already.
3030 LIMIT specifies the number of alias queries we are allowed to do,
3031 the walk stops when it reaches zero and NULL is returned. LIMIT
3032 is decremented by the number of alias queries (plus adjustments
3033 done by the callbacks) upon return.
3035 TODO: Cache the vector of equivalent vuses per ref, vuse pair. */
3038 walk_non_aliased_vuses (ao_ref
*ref
, tree vuse
,
3039 void *(*walker
)(ao_ref
*, tree
, void *),
3040 void *(*translate
)(ao_ref
*, tree
, void *, bool *),
3041 tree (*valueize
)(tree
),
3042 unsigned &limit
, void *data
)
3044 bitmap visited
= NULL
;
3046 bool translated
= false;
3048 timevar_push (TV_ALIAS_STMT_WALK
);
3054 /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */
3055 res
= (*walker
) (ref
, vuse
, data
);
3057 if (res
== (void *)-1)
3062 /* Lookup succeeded. */
3063 else if (res
!= NULL
)
3068 vuse
= valueize (vuse
);
3075 def_stmt
= SSA_NAME_DEF_STMT (vuse
);
3076 if (gimple_nop_p (def_stmt
))
3078 else if (gimple_code (def_stmt
) == GIMPLE_PHI
)
3079 vuse
= get_continuation_for_phi (def_stmt
, ref
, limit
,
3080 &visited
, translated
, translate
, data
);
3083 if ((int)limit
<= 0)
3088 if (stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
3092 bool disambiguate_only
= false;
3093 res
= (*translate
) (ref
, vuse
, data
, &disambiguate_only
);
3094 /* Failed lookup and translation. */
3095 if (res
== (void *)-1)
3100 /* Lookup succeeded. */
3101 else if (res
!= NULL
)
3103 /* Translation succeeded, continue walking. */
3104 translated
= translated
|| !disambiguate_only
;
3106 vuse
= gimple_vuse (def_stmt
);
3112 BITMAP_FREE (visited
);
3114 timevar_pop (TV_ALIAS_STMT_WALK
);
3120 /* Based on the memory reference REF call WALKER for each vdef which
3121 defining statement may clobber REF, starting with VDEF. If REF
3122 is NULL_TREE, each defining statement is visited.
3124 WALKER is called with REF, the current vdef and DATA. If WALKER
3125 returns true the walk is stopped, otherwise it continues.
3127 If function entry is reached, FUNCTION_ENTRY_REACHED is set to true.
3128 The pointer may be NULL and then we do not track this information.
3130 At PHI nodes walk_aliased_vdefs forks into one walk for reach
3131 PHI argument (but only one walk continues on merge points), the
3132 return value is true if any of the walks was successful.
3134 The function returns the number of statements walked or -1 if
3135 LIMIT stmts were walked and the walk was aborted at this point.
3136 If LIMIT is zero the walk is not aborted. */
3139 walk_aliased_vdefs_1 (ao_ref
*ref
, tree vdef
,
3140 bool (*walker
)(ao_ref
*, tree
, void *), void *data
,
3141 bitmap
*visited
, unsigned int cnt
,
3142 bool *function_entry_reached
, unsigned limit
)
3146 gimple
*def_stmt
= SSA_NAME_DEF_STMT (vdef
);
3149 && !bitmap_set_bit (*visited
, SSA_NAME_VERSION (vdef
)))
3152 if (gimple_nop_p (def_stmt
))
3154 if (function_entry_reached
)
3155 *function_entry_reached
= true;
3158 else if (gimple_code (def_stmt
) == GIMPLE_PHI
)
3162 *visited
= BITMAP_ALLOC (NULL
);
3163 for (i
= 0; i
< gimple_phi_num_args (def_stmt
); ++i
)
3165 int res
= walk_aliased_vdefs_1 (ref
,
3166 gimple_phi_arg_def (def_stmt
, i
),
3167 walker
, data
, visited
, cnt
,
3168 function_entry_reached
, limit
);
3176 /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */
3181 || stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
3182 && (*walker
) (ref
, vdef
, data
))
3185 vdef
= gimple_vuse (def_stmt
);
3191 walk_aliased_vdefs (ao_ref
*ref
, tree vdef
,
3192 bool (*walker
)(ao_ref
*, tree
, void *), void *data
,
3194 bool *function_entry_reached
, unsigned int limit
)
3196 bitmap local_visited
= NULL
;
3199 timevar_push (TV_ALIAS_STMT_WALK
);
3201 if (function_entry_reached
)
3202 *function_entry_reached
= false;
3204 ret
= walk_aliased_vdefs_1 (ref
, vdef
, walker
, data
,
3205 visited
? visited
: &local_visited
, 0,
3206 function_entry_reached
, limit
);
3208 BITMAP_FREE (local_visited
);
3210 timevar_pop (TV_ALIAS_STMT_WALK
);