1 /* Alias analysis for trees.
2 Copyright (C) 2004-2019 Free Software Foundation, Inc.
3 Contributed by Diego Novillo <dnovillo@redhat.com>
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3, or (at your option)
12 GCC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
23 #include "coretypes.h"
29 #include "timevar.h" /* for TV_ALIAS_STMT_WALK */
32 #include "tree-pretty-print.h"
34 #include "fold-const.h"
35 #include "langhooks.h"
39 #include "ipa-reference.h"
42 /* Broad overview of how alias analysis on gimple works:
44 Statements clobbering or using memory are linked through the
45 virtual operand factored use-def chain. The virtual operand
46 is unique per function, its symbol is accessible via gimple_vop (cfun).
47 Virtual operands are used for efficiently walking memory statements
48 in the gimple IL and are useful for things like value-numbering as
49 a generation count for memory references.
51 SSA_NAME pointers may have associated points-to information
52 accessible via the SSA_NAME_PTR_INFO macro. Flow-insensitive
53 points-to information is (re-)computed by the TODO_rebuild_alias
54 pass manager todo. Points-to information is also used for more
55 precise tracking of call-clobbered and call-used variables and
56 related disambiguations.
58 This file contains functions for disambiguating memory references,
59 the so called alias-oracle and tools for walking of the gimple IL.
61 The main alias-oracle entry-points are
63 bool stmt_may_clobber_ref_p (gimple *, tree)
65 This function queries if a statement may invalidate (parts of)
66 the memory designated by the reference tree argument.
68 bool ref_maybe_used_by_stmt_p (gimple *, tree)
70 This function queries if a statement may need (parts of) the
71 memory designated by the reference tree argument.
73 There are variants of these functions that only handle the call
74 part of a statement, call_may_clobber_ref_p and ref_maybe_used_by_call_p.
75 Note that these do not disambiguate against a possible call lhs.
77 bool refs_may_alias_p (tree, tree)
79 This function tries to disambiguate two reference trees.
81 bool ptr_deref_may_alias_global_p (tree)
83 This function queries if dereferencing a pointer variable may
86 More low-level disambiguators are available and documented in
87 this file. Low-level disambiguators dealing with points-to
88 information are in tree-ssa-structalias.c. */
91 /* Query statistics for the different low-level disambiguators.
92 A high-level query may trigger multiple of them. */
95 unsigned HOST_WIDE_INT refs_may_alias_p_may_alias
;
96 unsigned HOST_WIDE_INT refs_may_alias_p_no_alias
;
97 unsigned HOST_WIDE_INT ref_maybe_used_by_call_p_may_alias
;
98 unsigned HOST_WIDE_INT ref_maybe_used_by_call_p_no_alias
;
99 unsigned HOST_WIDE_INT call_may_clobber_ref_p_may_alias
;
100 unsigned HOST_WIDE_INT call_may_clobber_ref_p_no_alias
;
101 unsigned HOST_WIDE_INT aliasing_component_refs_p_may_alias
;
102 unsigned HOST_WIDE_INT aliasing_component_refs_p_no_alias
;
103 unsigned HOST_WIDE_INT nonoverlapping_component_refs_p_may_alias
;
104 unsigned HOST_WIDE_INT nonoverlapping_component_refs_p_no_alias
;
105 unsigned HOST_WIDE_INT nonoverlapping_component_refs_of_decl_p_may_alias
;
106 unsigned HOST_WIDE_INT nonoverlapping_component_refs_of_decl_p_no_alias
;
110 dump_alias_stats (FILE *s
)
112 fprintf (s
, "\nAlias oracle query stats:\n");
113 fprintf (s
, " refs_may_alias_p: "
114 HOST_WIDE_INT_PRINT_DEC
" disambiguations, "
115 HOST_WIDE_INT_PRINT_DEC
" queries\n",
116 alias_stats
.refs_may_alias_p_no_alias
,
117 alias_stats
.refs_may_alias_p_no_alias
118 + alias_stats
.refs_may_alias_p_may_alias
);
119 fprintf (s
, " ref_maybe_used_by_call_p: "
120 HOST_WIDE_INT_PRINT_DEC
" disambiguations, "
121 HOST_WIDE_INT_PRINT_DEC
" queries\n",
122 alias_stats
.ref_maybe_used_by_call_p_no_alias
,
123 alias_stats
.refs_may_alias_p_no_alias
124 + alias_stats
.ref_maybe_used_by_call_p_may_alias
);
125 fprintf (s
, " call_may_clobber_ref_p: "
126 HOST_WIDE_INT_PRINT_DEC
" disambiguations, "
127 HOST_WIDE_INT_PRINT_DEC
" queries\n",
128 alias_stats
.call_may_clobber_ref_p_no_alias
,
129 alias_stats
.call_may_clobber_ref_p_no_alias
130 + alias_stats
.call_may_clobber_ref_p_may_alias
);
131 fprintf (s
, " nonoverlapping_component_refs_p: "
132 HOST_WIDE_INT_PRINT_DEC
" disambiguations, "
133 HOST_WIDE_INT_PRINT_DEC
" queries\n",
134 alias_stats
.nonoverlapping_component_refs_p_no_alias
,
135 alias_stats
.nonoverlapping_component_refs_p_no_alias
136 + alias_stats
.nonoverlapping_component_refs_p_may_alias
);
137 fprintf (s
, " nonoverlapping_component_refs_of_decl_p: "
138 HOST_WIDE_INT_PRINT_DEC
" disambiguations, "
139 HOST_WIDE_INT_PRINT_DEC
" queries\n",
140 alias_stats
.nonoverlapping_component_refs_of_decl_p_no_alias
,
141 alias_stats
.nonoverlapping_component_refs_of_decl_p_no_alias
142 + alias_stats
.nonoverlapping_component_refs_of_decl_p_may_alias
);
143 fprintf (s
, " aliasing_component_refs_p: "
144 HOST_WIDE_INT_PRINT_DEC
" disambiguations, "
145 HOST_WIDE_INT_PRINT_DEC
" queries\n",
146 alias_stats
.aliasing_component_refs_p_no_alias
,
147 alias_stats
.aliasing_component_refs_p_no_alias
148 + alias_stats
.aliasing_component_refs_p_may_alias
);
149 dump_alias_stats_in_alias_c (s
);
153 /* Return true, if dereferencing PTR may alias with a global variable. */
156 ptr_deref_may_alias_global_p (tree ptr
)
158 struct ptr_info_def
*pi
;
160 /* If we end up with a pointer constant here that may point
162 if (TREE_CODE (ptr
) != SSA_NAME
)
165 pi
= SSA_NAME_PTR_INFO (ptr
);
167 /* If we do not have points-to information for this variable,
172 /* ??? This does not use TBAA to prune globals ptr may not access. */
173 return pt_solution_includes_global (&pi
->pt
);
176 /* Return true if dereferencing PTR may alias DECL.
177 The caller is responsible for applying TBAA to see if PTR
178 may access DECL at all. */
181 ptr_deref_may_alias_decl_p (tree ptr
, tree decl
)
183 struct ptr_info_def
*pi
;
185 /* Conversions are irrelevant for points-to information and
186 data-dependence analysis can feed us those. */
189 /* Anything we do not explicilty handle aliases. */
190 if ((TREE_CODE (ptr
) != SSA_NAME
191 && TREE_CODE (ptr
) != ADDR_EXPR
192 && TREE_CODE (ptr
) != POINTER_PLUS_EXPR
)
193 || !POINTER_TYPE_P (TREE_TYPE (ptr
))
195 && TREE_CODE (decl
) != PARM_DECL
196 && TREE_CODE (decl
) != RESULT_DECL
))
199 /* Disregard pointer offsetting. */
200 if (TREE_CODE (ptr
) == POINTER_PLUS_EXPR
)
204 ptr
= TREE_OPERAND (ptr
, 0);
206 while (TREE_CODE (ptr
) == POINTER_PLUS_EXPR
);
207 return ptr_deref_may_alias_decl_p (ptr
, decl
);
210 /* ADDR_EXPR pointers either just offset another pointer or directly
211 specify the pointed-to set. */
212 if (TREE_CODE (ptr
) == ADDR_EXPR
)
214 tree base
= get_base_address (TREE_OPERAND (ptr
, 0));
216 && (TREE_CODE (base
) == MEM_REF
217 || TREE_CODE (base
) == TARGET_MEM_REF
))
218 ptr
= TREE_OPERAND (base
, 0);
221 return compare_base_decls (base
, decl
) != 0;
223 && CONSTANT_CLASS_P (base
))
229 /* Non-aliased variables cannot be pointed to. */
230 if (!may_be_aliased (decl
))
233 /* If we do not have useful points-to information for this pointer
234 we cannot disambiguate anything else. */
235 pi
= SSA_NAME_PTR_INFO (ptr
);
239 return pt_solution_includes (&pi
->pt
, decl
);
242 /* Return true if dereferenced PTR1 and PTR2 may alias.
243 The caller is responsible for applying TBAA to see if accesses
244 through PTR1 and PTR2 may conflict at all. */
247 ptr_derefs_may_alias_p (tree ptr1
, tree ptr2
)
249 struct ptr_info_def
*pi1
, *pi2
;
251 /* Conversions are irrelevant for points-to information and
252 data-dependence analysis can feed us those. */
256 /* Disregard pointer offsetting. */
257 if (TREE_CODE (ptr1
) == POINTER_PLUS_EXPR
)
261 ptr1
= TREE_OPERAND (ptr1
, 0);
263 while (TREE_CODE (ptr1
) == POINTER_PLUS_EXPR
);
264 return ptr_derefs_may_alias_p (ptr1
, ptr2
);
266 if (TREE_CODE (ptr2
) == POINTER_PLUS_EXPR
)
270 ptr2
= TREE_OPERAND (ptr2
, 0);
272 while (TREE_CODE (ptr2
) == POINTER_PLUS_EXPR
);
273 return ptr_derefs_may_alias_p (ptr1
, ptr2
);
276 /* ADDR_EXPR pointers either just offset another pointer or directly
277 specify the pointed-to set. */
278 if (TREE_CODE (ptr1
) == ADDR_EXPR
)
280 tree base
= get_base_address (TREE_OPERAND (ptr1
, 0));
282 && (TREE_CODE (base
) == MEM_REF
283 || TREE_CODE (base
) == TARGET_MEM_REF
))
284 return ptr_derefs_may_alias_p (TREE_OPERAND (base
, 0), ptr2
);
287 return ptr_deref_may_alias_decl_p (ptr2
, base
);
291 if (TREE_CODE (ptr2
) == ADDR_EXPR
)
293 tree base
= get_base_address (TREE_OPERAND (ptr2
, 0));
295 && (TREE_CODE (base
) == MEM_REF
296 || TREE_CODE (base
) == TARGET_MEM_REF
))
297 return ptr_derefs_may_alias_p (ptr1
, TREE_OPERAND (base
, 0));
300 return ptr_deref_may_alias_decl_p (ptr1
, base
);
305 /* From here we require SSA name pointers. Anything else aliases. */
306 if (TREE_CODE (ptr1
) != SSA_NAME
307 || TREE_CODE (ptr2
) != SSA_NAME
308 || !POINTER_TYPE_P (TREE_TYPE (ptr1
))
309 || !POINTER_TYPE_P (TREE_TYPE (ptr2
)))
312 /* We may end up with two empty points-to solutions for two same pointers.
313 In this case we still want to say both pointers alias, so shortcut
318 /* If we do not have useful points-to information for either pointer
319 we cannot disambiguate anything else. */
320 pi1
= SSA_NAME_PTR_INFO (ptr1
);
321 pi2
= SSA_NAME_PTR_INFO (ptr2
);
325 /* ??? This does not use TBAA to prune decls from the intersection
326 that not both pointers may access. */
327 return pt_solutions_intersect (&pi1
->pt
, &pi2
->pt
);
330 /* Return true if dereferencing PTR may alias *REF.
331 The caller is responsible for applying TBAA to see if PTR
332 may access *REF at all. */
335 ptr_deref_may_alias_ref_p_1 (tree ptr
, ao_ref
*ref
)
337 tree base
= ao_ref_base (ref
);
339 if (TREE_CODE (base
) == MEM_REF
340 || TREE_CODE (base
) == TARGET_MEM_REF
)
341 return ptr_derefs_may_alias_p (ptr
, TREE_OPERAND (base
, 0));
342 else if (DECL_P (base
))
343 return ptr_deref_may_alias_decl_p (ptr
, base
);
348 /* Returns true if PTR1 and PTR2 compare unequal because of points-to. */
351 ptrs_compare_unequal (tree ptr1
, tree ptr2
)
353 /* First resolve the pointers down to a SSA name pointer base or
354 a VAR_DECL, PARM_DECL or RESULT_DECL. This explicitely does
355 not yet try to handle LABEL_DECLs, FUNCTION_DECLs, CONST_DECLs
356 or STRING_CSTs which needs points-to adjustments to track them
357 in the points-to sets. */
358 tree obj1
= NULL_TREE
;
359 tree obj2
= NULL_TREE
;
360 if (TREE_CODE (ptr1
) == ADDR_EXPR
)
362 tree tem
= get_base_address (TREE_OPERAND (ptr1
, 0));
366 || TREE_CODE (tem
) == PARM_DECL
367 || TREE_CODE (tem
) == RESULT_DECL
)
369 else if (TREE_CODE (tem
) == MEM_REF
)
370 ptr1
= TREE_OPERAND (tem
, 0);
372 if (TREE_CODE (ptr2
) == ADDR_EXPR
)
374 tree tem
= get_base_address (TREE_OPERAND (ptr2
, 0));
378 || TREE_CODE (tem
) == PARM_DECL
379 || TREE_CODE (tem
) == RESULT_DECL
)
381 else if (TREE_CODE (tem
) == MEM_REF
)
382 ptr2
= TREE_OPERAND (tem
, 0);
385 /* Canonicalize ptr vs. object. */
386 if (TREE_CODE (ptr1
) == SSA_NAME
&& obj2
)
388 std::swap (ptr1
, ptr2
);
389 std::swap (obj1
, obj2
);
393 /* Other code handles this correctly, no need to duplicate it here. */;
394 else if (obj1
&& TREE_CODE (ptr2
) == SSA_NAME
)
396 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (ptr2
);
397 /* We may not use restrict to optimize pointer comparisons.
398 See PR71062. So we have to assume that restrict-pointed-to
399 may be in fact obj1. */
401 || pi
->pt
.vars_contains_restrict
402 || pi
->pt
.vars_contains_interposable
)
405 && (TREE_STATIC (obj1
) || DECL_EXTERNAL (obj1
)))
407 varpool_node
*node
= varpool_node::get (obj1
);
408 /* If obj1 may bind to NULL give up (see below). */
410 || ! node
->nonzero_address ()
411 || ! decl_binds_to_current_def_p (obj1
))
414 return !pt_solution_includes (&pi
->pt
, obj1
);
417 /* ??? We'd like to handle ptr1 != NULL and ptr1 != ptr2
418 but those require pt.null to be conservatively correct. */
423 /* Returns whether reference REF to BASE may refer to global memory. */
426 ref_may_alias_global_p_1 (tree base
)
429 return is_global_var (base
);
430 else if (TREE_CODE (base
) == MEM_REF
431 || TREE_CODE (base
) == TARGET_MEM_REF
)
432 return ptr_deref_may_alias_global_p (TREE_OPERAND (base
, 0));
437 ref_may_alias_global_p (ao_ref
*ref
)
439 tree base
= ao_ref_base (ref
);
440 return ref_may_alias_global_p_1 (base
);
444 ref_may_alias_global_p (tree ref
)
446 tree base
= get_base_address (ref
);
447 return ref_may_alias_global_p_1 (base
);
450 /* Return true whether STMT may clobber global memory. */
453 stmt_may_clobber_global_p (gimple
*stmt
)
457 if (!gimple_vdef (stmt
))
460 /* ??? We can ask the oracle whether an artificial pointer
461 dereference with a pointer with points-to information covering
462 all global memory (what about non-address taken memory?) maybe
463 clobbered by this call. As there is at the moment no convenient
464 way of doing that without generating garbage do some manual
466 ??? We could make a NULL ao_ref argument to the various
467 predicates special, meaning any global memory. */
469 switch (gimple_code (stmt
))
472 lhs
= gimple_assign_lhs (stmt
);
473 return (TREE_CODE (lhs
) != SSA_NAME
474 && ref_may_alias_global_p (lhs
));
483 /* Dump alias information on FILE. */
486 dump_alias_info (FILE *file
)
491 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
494 fprintf (file
, "\n\nAlias information for %s\n\n", funcname
);
496 fprintf (file
, "Aliased symbols\n\n");
498 FOR_EACH_LOCAL_DECL (cfun
, i
, var
)
500 if (may_be_aliased (var
))
501 dump_variable (file
, var
);
504 fprintf (file
, "\nCall clobber information\n");
506 fprintf (file
, "\nESCAPED");
507 dump_points_to_solution (file
, &cfun
->gimple_df
->escaped
);
509 fprintf (file
, "\n\nFlow-insensitive points-to information\n\n");
511 FOR_EACH_SSA_NAME (i
, ptr
, cfun
)
513 struct ptr_info_def
*pi
;
515 if (!POINTER_TYPE_P (TREE_TYPE (ptr
))
516 || SSA_NAME_IN_FREE_LIST (ptr
))
519 pi
= SSA_NAME_PTR_INFO (ptr
);
521 dump_points_to_info_for (file
, ptr
);
524 fprintf (file
, "\n");
528 /* Dump alias information on stderr. */
531 debug_alias_info (void)
533 dump_alias_info (stderr
);
537 /* Dump the points-to set *PT into FILE. */
540 dump_points_to_solution (FILE *file
, struct pt_solution
*pt
)
543 fprintf (file
, ", points-to anything");
546 fprintf (file
, ", points-to non-local");
549 fprintf (file
, ", points-to escaped");
552 fprintf (file
, ", points-to unit escaped");
555 fprintf (file
, ", points-to NULL");
559 fprintf (file
, ", points-to vars: ");
560 dump_decl_set (file
, pt
->vars
);
561 if (pt
->vars_contains_nonlocal
562 || pt
->vars_contains_escaped
563 || pt
->vars_contains_escaped_heap
564 || pt
->vars_contains_restrict
)
566 const char *comma
= "";
567 fprintf (file
, " (");
568 if (pt
->vars_contains_nonlocal
)
570 fprintf (file
, "nonlocal");
573 if (pt
->vars_contains_escaped
)
575 fprintf (file
, "%sescaped", comma
);
578 if (pt
->vars_contains_escaped_heap
)
580 fprintf (file
, "%sescaped heap", comma
);
583 if (pt
->vars_contains_restrict
)
585 fprintf (file
, "%srestrict", comma
);
588 if (pt
->vars_contains_interposable
)
589 fprintf (file
, "%sinterposable", comma
);
596 /* Unified dump function for pt_solution. */
599 debug (pt_solution
&ref
)
601 dump_points_to_solution (stderr
, &ref
);
605 debug (pt_solution
*ptr
)
610 fprintf (stderr
, "<nil>\n");
614 /* Dump points-to information for SSA_NAME PTR into FILE. */
617 dump_points_to_info_for (FILE *file
, tree ptr
)
619 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (ptr
);
621 print_generic_expr (file
, ptr
, dump_flags
);
624 dump_points_to_solution (file
, &pi
->pt
);
626 fprintf (file
, ", points-to anything");
628 fprintf (file
, "\n");
632 /* Dump points-to information for VAR into stderr. */
635 debug_points_to_info_for (tree var
)
637 dump_points_to_info_for (stderr
, var
);
641 /* Initializes the alias-oracle reference representation *R from REF. */
644 ao_ref_init (ao_ref
*r
, tree ref
)
651 r
->ref_alias_set
= -1;
652 r
->base_alias_set
= -1;
653 r
->volatile_p
= ref
? TREE_THIS_VOLATILE (ref
) : false;
656 /* Returns the base object of the memory reference *REF. */
659 ao_ref_base (ao_ref
*ref
)
665 ref
->base
= get_ref_base_and_extent (ref
->ref
, &ref
->offset
, &ref
->size
,
666 &ref
->max_size
, &reverse
);
670 /* Returns the base object alias set of the memory reference *REF. */
673 ao_ref_base_alias_set (ao_ref
*ref
)
676 if (ref
->base_alias_set
!= -1)
677 return ref
->base_alias_set
;
681 while (handled_component_p (base_ref
))
682 base_ref
= TREE_OPERAND (base_ref
, 0);
683 ref
->base_alias_set
= get_alias_set (base_ref
);
684 return ref
->base_alias_set
;
687 /* Returns the reference alias set of the memory reference *REF. */
690 ao_ref_alias_set (ao_ref
*ref
)
692 if (ref
->ref_alias_set
!= -1)
693 return ref
->ref_alias_set
;
694 ref
->ref_alias_set
= get_alias_set (ref
->ref
);
695 return ref
->ref_alias_set
;
698 /* Init an alias-oracle reference representation from a gimple pointer
699 PTR and a gimple size SIZE in bytes. If SIZE is NULL_TREE then the
700 size is assumed to be unknown. The access is assumed to be only
701 to or after of the pointer target, not before it. */
704 ao_ref_init_from_ptr_and_size (ao_ref
*ref
, tree ptr
, tree size
)
706 poly_int64 t
, size_hwi
, extra_offset
= 0;
707 ref
->ref
= NULL_TREE
;
708 if (TREE_CODE (ptr
) == SSA_NAME
)
710 gimple
*stmt
= SSA_NAME_DEF_STMT (ptr
);
711 if (gimple_assign_single_p (stmt
)
712 && gimple_assign_rhs_code (stmt
) == ADDR_EXPR
)
713 ptr
= gimple_assign_rhs1 (stmt
);
714 else if (is_gimple_assign (stmt
)
715 && gimple_assign_rhs_code (stmt
) == POINTER_PLUS_EXPR
716 && ptrdiff_tree_p (gimple_assign_rhs2 (stmt
), &extra_offset
))
718 ptr
= gimple_assign_rhs1 (stmt
);
719 extra_offset
*= BITS_PER_UNIT
;
723 if (TREE_CODE (ptr
) == ADDR_EXPR
)
725 ref
->base
= get_addr_base_and_unit_offset (TREE_OPERAND (ptr
, 0), &t
);
727 ref
->offset
= BITS_PER_UNIT
* t
;
732 ref
->base
= get_base_address (TREE_OPERAND (ptr
, 0));
737 gcc_assert (POINTER_TYPE_P (TREE_TYPE (ptr
)));
738 ref
->base
= build2 (MEM_REF
, char_type_node
,
739 ptr
, null_pointer_node
);
742 ref
->offset
+= extra_offset
;
744 && poly_int_tree_p (size
, &size_hwi
)
745 && coeffs_in_range_p (size_hwi
, 0, HOST_WIDE_INT_MAX
/ BITS_PER_UNIT
))
746 ref
->max_size
= ref
->size
= size_hwi
* BITS_PER_UNIT
;
748 ref
->max_size
= ref
->size
= -1;
749 ref
->ref_alias_set
= 0;
750 ref
->base_alias_set
= 0;
751 ref
->volatile_p
= false;
754 /* S1 and S2 are TYPE_SIZE or DECL_SIZE. Compare them:
757 Return 0 if equal or incomparable. */
760 compare_sizes (tree s1
, tree s2
)
768 if (!poly_int_tree_p (s1
, &size1
) || !poly_int_tree_p (s2
, &size2
))
770 if (known_lt (size1
, size2
))
772 if (known_lt (size2
, size1
))
777 /* Compare TYPE1 and TYPE2 by its size.
778 Return -1 if size of TYPE1 < size of TYPE2
779 Return 1 if size of TYPE1 > size of TYPE2
780 Return 0 if types are of equal sizes or we can not compare them. */
783 compare_type_sizes (tree type1
, tree type2
)
785 /* Be conservative for arrays and vectors. We want to support partial
786 overlap on int[3] and int[3] as tested in gcc.dg/torture/alias-2.c. */
787 while (TREE_CODE (type1
) == ARRAY_TYPE
788 || TREE_CODE (type1
) == VECTOR_TYPE
)
789 type1
= TREE_TYPE (type1
);
790 while (TREE_CODE (type2
) == ARRAY_TYPE
791 || TREE_CODE (type2
) == VECTOR_TYPE
)
792 type2
= TREE_TYPE (type2
);
793 return compare_sizes (TYPE_SIZE (type1
), TYPE_SIZE (type2
));
796 /* Return 1 if TYPE1 and TYPE2 are to be considered equivalent for the
797 purpose of TBAA. Return 0 if they are distinct and -1 if we cannot
801 same_type_for_tbaa (tree type1
, tree type2
)
803 type1
= TYPE_MAIN_VARIANT (type1
);
804 type2
= TYPE_MAIN_VARIANT (type2
);
806 /* Handle the most common case first. */
810 /* If we would have to do structural comparison bail out. */
811 if (TYPE_STRUCTURAL_EQUALITY_P (type1
)
812 || TYPE_STRUCTURAL_EQUALITY_P (type2
))
815 /* Compare the canonical types. */
816 if (TYPE_CANONICAL (type1
) == TYPE_CANONICAL (type2
))
819 /* ??? Array types are not properly unified in all cases as we have
820 spurious changes in the index types for example. Removing this
821 causes all sorts of problems with the Fortran frontend. */
822 if (TREE_CODE (type1
) == ARRAY_TYPE
823 && TREE_CODE (type2
) == ARRAY_TYPE
)
826 /* ??? In Ada, an lvalue of an unconstrained type can be used to access an
827 object of one of its constrained subtypes, e.g. when a function with an
828 unconstrained parameter passed by reference is called on an object and
829 inlined. But, even in the case of a fixed size, type and subtypes are
830 not equivalent enough as to share the same TYPE_CANONICAL, since this
831 would mean that conversions between them are useless, whereas they are
832 not (e.g. type and subtypes can have different modes). So, in the end,
833 they are only guaranteed to have the same alias set. */
834 if (get_alias_set (type1
) == get_alias_set (type2
))
837 /* The types are known to be not equal. */
841 /* Return true if TYPE is a composite type (i.e. we may apply one of handled
842 components on it). */
845 type_has_components_p (tree type
)
847 return AGGREGATE_TYPE_P (type
) || VECTOR_TYPE_P (type
)
848 || TREE_CODE (type
) == COMPLEX_TYPE
;
851 /* Determine if the two component references REF1 and REF2 which are
852 based on access types TYPE1 and TYPE2 and of which at least one is based
853 on an indirect reference may alias. REF2 is the only one that can
854 be a decl in which case REF2_IS_DECL is true.
855 REF1_ALIAS_SET, BASE1_ALIAS_SET, REF2_ALIAS_SET and BASE2_ALIAS_SET
856 are the respective alias sets. */
859 aliasing_component_refs_p (tree ref1
,
860 alias_set_type ref1_alias_set
,
861 alias_set_type base1_alias_set
,
862 poly_int64 offset1
, poly_int64 max_size1
,
864 alias_set_type ref2_alias_set
,
865 alias_set_type base2_alias_set
,
866 poly_int64 offset2
, poly_int64 max_size2
,
869 /* If one reference is a component references through pointers try to find a
870 common base and apply offset based disambiguation. This handles
872 struct A { int i; int j; } *q;
873 struct B { struct A a; int k; } *p;
874 disambiguating q->i and p->a.j. */
878 int same_p1
= 0, same_p2
= 0;
879 bool maybe_match
= false;
880 tree end_struct_ref1
= NULL
, end_struct_ref2
= NULL
;
882 /* Choose bases and base types to search for. */
884 while (handled_component_p (base1
))
886 /* Generally access paths are monotous in the size of object. The
887 exception are trailing arrays of structures. I.e.
888 struct a {int array[0];};
890 struct a {int array1[0]; int array[];};
891 Such struct has size 0 but accesses to a.array may have non-zero size.
892 In this case the size of TREE_TYPE (base1) is smaller than
893 size of TREE_TYPE (TREE_OPERNAD (base1, 0)).
895 Because we compare sizes of arrays just by sizes of their elements,
896 we only need to care about zero sized array fields here. */
897 if (TREE_CODE (base1
) == COMPONENT_REF
898 && TREE_CODE (TREE_TYPE (TREE_OPERAND (base1
, 1))) == ARRAY_TYPE
899 && (!TYPE_SIZE (TREE_TYPE (TREE_OPERAND (base1
, 1)))
900 || integer_zerop (TYPE_SIZE (TREE_TYPE (TREE_OPERAND (base1
, 1)))))
901 && array_at_struct_end_p (base1
))
903 gcc_checking_assert (!end_struct_ref1
);
904 end_struct_ref1
= base1
;
906 base1
= TREE_OPERAND (base1
, 0);
908 type1
= TREE_TYPE (base1
);
910 while (handled_component_p (base2
))
912 if (TREE_CODE (base2
) == COMPONENT_REF
913 && TREE_CODE (TREE_TYPE (TREE_OPERAND (base2
, 1))) == ARRAY_TYPE
914 && (!TYPE_SIZE (TREE_TYPE (TREE_OPERAND (base2
, 1)))
915 || integer_zerop (TYPE_SIZE (TREE_TYPE (TREE_OPERAND (base2
, 1)))))
916 && array_at_struct_end_p (base2
))
918 gcc_checking_assert (!end_struct_ref2
);
919 end_struct_ref2
= base2
;
921 base2
= TREE_OPERAND (base2
, 0);
923 type2
= TREE_TYPE (base2
);
925 /* Now search for the type1 in the access path of ref2. This
926 would be a common base for doing offset based disambiguation on.
927 This however only makes sense if type2 is big enough to hold type1. */
928 int cmp_outer
= compare_type_sizes (type2
, type1
);
930 /* If type2 is big enough to contain type1 walk its access path.
931 We also need to care of arrays at the end of structs that may extend
932 beyond the end of structure. */
935 && compare_type_sizes (TREE_TYPE (end_struct_ref2
), type1
) >= 0))
940 /* We walk from inner type to the outer types. If type we see is
941 already too large to be part of type1, terminate the search. */
942 int cmp
= compare_type_sizes (type1
, TREE_TYPE (*refp
));
946 || compare_type_sizes (TREE_TYPE (end_struct_ref1
),
947 TREE_TYPE (*refp
)) < 0))
949 /* If types may be of same size, see if we can decide about their
953 same_p2
= same_type_for_tbaa (TREE_TYPE (*refp
), type1
);
956 /* In case we can't decide whether types are same try to
957 continue looking for the exact match.
958 Remember however that we possibly saw a match
959 to bypass the access path continuations tests we do later. */
963 if (!handled_component_p (*refp
))
965 refp
= &TREE_OPERAND (*refp
, 0);
969 poly_int64 offadj
, sztmp
, msztmp
;
972 /* We assume that arrays can overlap by multiple of their elements
973 size as tested in gcc.dg/torture/alias-2.c.
974 This partial overlap happen only when both arrays are bases of
975 the access and not contained within another component ref.
976 To be safe we also assume partial overlap for VLAs. */
977 if (TREE_CODE (TREE_TYPE (base1
)) == ARRAY_TYPE
978 && (!TYPE_SIZE (TREE_TYPE (base1
))
979 || TREE_CODE (TYPE_SIZE (TREE_TYPE (base1
))) != INTEGER_CST
980 || (*refp
== base2
&& !ref2_is_decl
)))
982 ++alias_stats
.aliasing_component_refs_p_may_alias
;
986 get_ref_base_and_extent (*refp
, &offadj
, &sztmp
, &msztmp
, &reverse
);
988 get_ref_base_and_extent (base1
, &offadj
, &sztmp
, &msztmp
, &reverse
);
990 if (ranges_maybe_overlap_p (offset1
, max_size1
, offset2
, max_size2
))
992 ++alias_stats
.aliasing_component_refs_p_may_alias
;
997 ++alias_stats
.aliasing_component_refs_p_no_alias
;
1003 /* If we didn't find a common base, try the other way around. */
1006 && compare_type_sizes (TREE_TYPE (end_struct_ref1
), type1
) <= 0))
1011 int cmp
= compare_type_sizes (type2
, TREE_TYPE (*refp
));
1013 && (!end_struct_ref2
1014 || compare_type_sizes (TREE_TYPE (end_struct_ref2
),
1015 TREE_TYPE (*refp
)) < 0))
1017 /* If types may be of same size, see if we can decide about their
1021 same_p1
= same_type_for_tbaa (TREE_TYPE (*refp
), type2
);
1027 if (!handled_component_p (*refp
))
1029 refp
= &TREE_OPERAND (*refp
, 0);
1033 poly_int64 offadj
, sztmp
, msztmp
;
1036 if (TREE_CODE (TREE_TYPE (base2
)) == ARRAY_TYPE
1037 && (!TYPE_SIZE (TREE_TYPE (base2
))
1038 || TREE_CODE (TYPE_SIZE (TREE_TYPE (base2
))) != INTEGER_CST
1039 || (*refp
== base1
&& !ref2_is_decl
)))
1041 ++alias_stats
.aliasing_component_refs_p_may_alias
;
1045 get_ref_base_and_extent (*refp
, &offadj
, &sztmp
, &msztmp
, &reverse
);
1047 get_ref_base_and_extent (base2
, &offadj
, &sztmp
, &msztmp
, &reverse
);
1049 if (ranges_maybe_overlap_p (offset1
, max_size1
, offset2
, max_size2
))
1051 ++alias_stats
.aliasing_component_refs_p_may_alias
;
1056 ++alias_stats
.aliasing_component_refs_p_no_alias
;
1062 /* In the following code we make an assumption that the types in access
1063 paths do not overlap and thus accesses alias only if one path can be
1064 continuation of another. If we was not able to decide about equivalence,
1065 we need to give up. */
1069 /* If we have two type access paths B1.path1 and B2.path2 they may
1070 only alias if either B1 is in B2.path2 or B2 is in B1.path1.
1071 But we can still have a path that goes B1.path1...B2.path2 with
1072 a part that we do not see. So we can only disambiguate now
1073 if there is no B2 in the tail of path1 and no B1 on the
1075 if (compare_type_sizes (TREE_TYPE (ref2
), type1
) >= 0
1076 && (!end_struct_ref1
1077 || compare_type_sizes (TREE_TYPE (ref2
),
1078 TREE_TYPE (end_struct_ref1
)) >= 0)
1079 && type_has_components_p (TREE_TYPE (ref2
))
1080 && (base1_alias_set
== ref2_alias_set
1081 || alias_set_subset_of (base1_alias_set
, ref2_alias_set
)))
1083 ++alias_stats
.aliasing_component_refs_p_may_alias
;
1086 /* If this is ptr vs. decl then we know there is no ptr ... decl path. */
1088 && compare_type_sizes (TREE_TYPE (ref1
), type2
) >= 0
1089 && (!end_struct_ref2
1090 || compare_type_sizes (TREE_TYPE (ref1
),
1091 TREE_TYPE (end_struct_ref2
)) >= 0)
1092 && type_has_components_p (TREE_TYPE (ref1
))
1093 && (base2_alias_set
== ref1_alias_set
1094 || alias_set_subset_of (base2_alias_set
, ref1_alias_set
)))
1096 ++alias_stats
.aliasing_component_refs_p_may_alias
;
1099 ++alias_stats
.aliasing_component_refs_p_no_alias
;
1103 /* Return true if we can determine that component references REF1 and REF2,
1104 that are within a common DECL, cannot overlap. */
1107 nonoverlapping_component_refs_of_decl_p (tree ref1
, tree ref2
)
1109 auto_vec
<tree
, 16> component_refs1
;
1110 auto_vec
<tree
, 16> component_refs2
;
1112 /* Create the stack of handled components for REF1. */
1113 while (handled_component_p (ref1
))
1115 component_refs1
.safe_push (ref1
);
1116 ref1
= TREE_OPERAND (ref1
, 0);
1118 if (TREE_CODE (ref1
) == MEM_REF
)
1120 if (!integer_zerop (TREE_OPERAND (ref1
, 1)))
1122 ++alias_stats
.nonoverlapping_component_refs_of_decl_p_may_alias
;
1125 ref1
= TREE_OPERAND (TREE_OPERAND (ref1
, 0), 0);
1128 /* Create the stack of handled components for REF2. */
1129 while (handled_component_p (ref2
))
1131 component_refs2
.safe_push (ref2
);
1132 ref2
= TREE_OPERAND (ref2
, 0);
1134 if (TREE_CODE (ref2
) == MEM_REF
)
1136 if (!integer_zerop (TREE_OPERAND (ref2
, 1)))
1138 ++alias_stats
.nonoverlapping_component_refs_of_decl_p_may_alias
;
1141 ref2
= TREE_OPERAND (TREE_OPERAND (ref2
, 0), 0);
1144 /* Bases must be either same or uncomparable. */
1145 gcc_checking_assert (ref1
== ref2
1146 || (DECL_P (ref1
) && DECL_P (ref2
)
1147 && compare_base_decls (ref1
, ref2
) != 0));
1149 /* Pop the stacks in parallel and examine the COMPONENT_REFs of the same
1150 rank. This is sufficient because we start from the same DECL and you
1151 cannot reference several fields at a time with COMPONENT_REFs (unlike
1152 with ARRAY_RANGE_REFs for arrays) so you always need the same number
1153 of them to access a sub-component, unless you're in a union, in which
1154 case the return value will precisely be false. */
1159 if (component_refs1
.is_empty ())
1161 ++alias_stats
.nonoverlapping_component_refs_of_decl_p_may_alias
;
1164 ref1
= component_refs1
.pop ();
1166 while (!RECORD_OR_UNION_TYPE_P (TREE_TYPE (TREE_OPERAND (ref1
, 0))));
1170 if (component_refs2
.is_empty ())
1172 ++alias_stats
.nonoverlapping_component_refs_of_decl_p_may_alias
;
1175 ref2
= component_refs2
.pop ();
1177 while (!RECORD_OR_UNION_TYPE_P (TREE_TYPE (TREE_OPERAND (ref2
, 0))));
1179 /* Beware of BIT_FIELD_REF. */
1180 if (TREE_CODE (ref1
) != COMPONENT_REF
1181 || TREE_CODE (ref2
) != COMPONENT_REF
)
1183 ++alias_stats
.nonoverlapping_component_refs_of_decl_p_may_alias
;
1187 tree field1
= TREE_OPERAND (ref1
, 1);
1188 tree field2
= TREE_OPERAND (ref2
, 1);
1190 /* ??? We cannot simply use the type of operand #0 of the refs here
1191 as the Fortran compiler smuggles type punning into COMPONENT_REFs
1192 for common blocks instead of using unions like everyone else. */
1193 tree type1
= DECL_CONTEXT (field1
);
1194 tree type2
= DECL_CONTEXT (field2
);
1196 /* We cannot disambiguate fields in a union or qualified union. */
1197 if (type1
!= type2
|| TREE_CODE (type1
) != RECORD_TYPE
)
1199 ++alias_stats
.nonoverlapping_component_refs_of_decl_p_may_alias
;
1203 if (field1
!= field2
)
1205 /* A field and its representative need to be considered the
1207 if (DECL_BIT_FIELD_REPRESENTATIVE (field1
) == field2
1208 || DECL_BIT_FIELD_REPRESENTATIVE (field2
) == field1
)
1210 ++alias_stats
.nonoverlapping_component_refs_of_decl_p_may_alias
;
1213 /* Different fields of the same record type cannot overlap.
1214 ??? Bitfields can overlap at RTL level so punt on them. */
1215 if (DECL_BIT_FIELD (field1
) && DECL_BIT_FIELD (field2
))
1217 ++alias_stats
.nonoverlapping_component_refs_of_decl_p_may_alias
;
1220 ++alias_stats
.nonoverlapping_component_refs_of_decl_p_no_alias
;
1225 ++alias_stats
.nonoverlapping_component_refs_of_decl_p_may_alias
;
1229 /* qsort compare function to sort FIELD_DECLs after their
1230 DECL_FIELD_CONTEXT TYPE_UID. */
1233 ncr_compar (const void *field1_
, const void *field2_
)
1235 const_tree field1
= *(const_tree
*) const_cast <void *>(field1_
);
1236 const_tree field2
= *(const_tree
*) const_cast <void *>(field2_
);
1237 unsigned int uid1
= TYPE_UID (DECL_FIELD_CONTEXT (field1
));
1238 unsigned int uid2
= TYPE_UID (DECL_FIELD_CONTEXT (field2
));
1241 else if (uid1
> uid2
)
1246 /* Return true if we can determine that the fields referenced cannot
1247 overlap for any pair of objects. */
1250 nonoverlapping_component_refs_p (const_tree x
, const_tree y
)
1252 if (!flag_strict_aliasing
1254 || !handled_component_p (x
)
1255 || !handled_component_p (y
))
1257 ++alias_stats
.nonoverlapping_component_refs_p_may_alias
;
1261 auto_vec
<const_tree
, 16> fieldsx
;
1262 while (handled_component_p (x
))
1264 if (TREE_CODE (x
) == COMPONENT_REF
)
1266 tree field
= TREE_OPERAND (x
, 1);
1267 tree type
= DECL_FIELD_CONTEXT (field
);
1268 if (TREE_CODE (type
) == RECORD_TYPE
)
1269 fieldsx
.safe_push (field
);
1271 else if (TREE_CODE (x
) == VIEW_CONVERT_EXPR
1272 || TREE_CODE (x
) == BIT_FIELD_REF
)
1273 fieldsx
.truncate (0);
1274 x
= TREE_OPERAND (x
, 0);
1276 if (fieldsx
.length () == 0)
1278 auto_vec
<const_tree
, 16> fieldsy
;
1279 while (handled_component_p (y
))
1281 if (TREE_CODE (y
) == COMPONENT_REF
)
1283 tree field
= TREE_OPERAND (y
, 1);
1284 tree type
= DECL_FIELD_CONTEXT (field
);
1285 if (TREE_CODE (type
) == RECORD_TYPE
)
1286 fieldsy
.safe_push (TREE_OPERAND (y
, 1));
1288 else if (TREE_CODE (y
) == VIEW_CONVERT_EXPR
1289 || TREE_CODE (y
) == BIT_FIELD_REF
)
1290 fieldsy
.truncate (0);
1291 y
= TREE_OPERAND (y
, 0);
1293 if (fieldsy
.length () == 0)
1295 ++alias_stats
.nonoverlapping_component_refs_p_may_alias
;
1299 /* Most common case first. */
1300 if (fieldsx
.length () == 1
1301 && fieldsy
.length () == 1)
1303 if ((DECL_FIELD_CONTEXT (fieldsx
[0])
1304 == DECL_FIELD_CONTEXT (fieldsy
[0]))
1305 && fieldsx
[0] != fieldsy
[0]
1306 && !(DECL_BIT_FIELD (fieldsx
[0]) && DECL_BIT_FIELD (fieldsy
[0])))
1308 ++alias_stats
.nonoverlapping_component_refs_p_no_alias
;
1313 ++alias_stats
.nonoverlapping_component_refs_p_may_alias
;
1318 if (fieldsx
.length () == 2)
1320 if (ncr_compar (&fieldsx
[0], &fieldsx
[1]) == 1)
1321 std::swap (fieldsx
[0], fieldsx
[1]);
1324 fieldsx
.qsort (ncr_compar
);
1326 if (fieldsy
.length () == 2)
1328 if (ncr_compar (&fieldsy
[0], &fieldsy
[1]) == 1)
1329 std::swap (fieldsy
[0], fieldsy
[1]);
1332 fieldsy
.qsort (ncr_compar
);
1334 unsigned i
= 0, j
= 0;
1337 const_tree fieldx
= fieldsx
[i
];
1338 const_tree fieldy
= fieldsy
[j
];
1339 tree typex
= DECL_FIELD_CONTEXT (fieldx
);
1340 tree typey
= DECL_FIELD_CONTEXT (fieldy
);
1343 /* We're left with accessing different fields of a structure,
1344 no possible overlap. */
1345 if (fieldx
!= fieldy
)
1347 /* A field and its representative need to be considered the
1349 if (DECL_BIT_FIELD_REPRESENTATIVE (fieldx
) == fieldy
1350 || DECL_BIT_FIELD_REPRESENTATIVE (fieldy
) == fieldx
)
1352 ++alias_stats
.nonoverlapping_component_refs_p_may_alias
;
1355 /* Different fields of the same record type cannot overlap.
1356 ??? Bitfields can overlap at RTL level so punt on them. */
1357 if (DECL_BIT_FIELD (fieldx
) && DECL_BIT_FIELD (fieldy
))
1359 ++alias_stats
.nonoverlapping_component_refs_p_may_alias
;
1362 ++alias_stats
.nonoverlapping_component_refs_p_no_alias
;
1366 if (TYPE_UID (typex
) < TYPE_UID (typey
))
1369 if (i
== fieldsx
.length ())
1375 if (j
== fieldsy
.length ())
1381 ++alias_stats
.nonoverlapping_component_refs_p_may_alias
;
1386 /* Return true if two memory references based on the variables BASE1
1387 and BASE2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and
1388 [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. REF1 and REF2
1389 if non-NULL are the complete memory reference trees. */
1392 decl_refs_may_alias_p (tree ref1
, tree base1
,
1393 poly_int64 offset1
, poly_int64 max_size1
,
1394 tree ref2
, tree base2
,
1395 poly_int64 offset2
, poly_int64 max_size2
)
1397 gcc_checking_assert (DECL_P (base1
) && DECL_P (base2
));
1399 /* If both references are based on different variables, they cannot alias. */
1400 if (compare_base_decls (base1
, base2
) == 0)
1403 /* If both references are based on the same variable, they cannot alias if
1404 the accesses do not overlap. */
1405 if (!ranges_maybe_overlap_p (offset1
, max_size1
, offset2
, max_size2
))
1408 /* For components with variable position, the above test isn't sufficient,
1409 so we disambiguate component references manually. */
1411 && handled_component_p (ref1
) && handled_component_p (ref2
)
1412 && nonoverlapping_component_refs_of_decl_p (ref1
, ref2
))
1418 /* Return true if an indirect reference based on *PTR1 constrained
1419 to [OFFSET1, OFFSET1 + MAX_SIZE1) may alias a variable based on BASE2
1420 constrained to [OFFSET2, OFFSET2 + MAX_SIZE2). *PTR1 and BASE2 have
1421 the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1
1422 in which case they are computed on-demand. REF1 and REF2
1423 if non-NULL are the complete memory reference trees. */
1426 indirect_ref_may_alias_decl_p (tree ref1 ATTRIBUTE_UNUSED
, tree base1
,
1427 poly_int64 offset1
, poly_int64 max_size1
,
1428 alias_set_type ref1_alias_set
,
1429 alias_set_type base1_alias_set
,
1430 tree ref2 ATTRIBUTE_UNUSED
, tree base2
,
1431 poly_int64 offset2
, poly_int64 max_size2
,
1432 alias_set_type ref2_alias_set
,
1433 alias_set_type base2_alias_set
, bool tbaa_p
)
1436 tree ptrtype1
, dbase2
;
1438 gcc_checking_assert ((TREE_CODE (base1
) == MEM_REF
1439 || TREE_CODE (base1
) == TARGET_MEM_REF
)
1442 ptr1
= TREE_OPERAND (base1
, 0);
1443 poly_offset_int moff
= mem_ref_offset (base1
) << LOG2_BITS_PER_UNIT
;
1445 /* If only one reference is based on a variable, they cannot alias if
1446 the pointer access is beyond the extent of the variable access.
1447 (the pointer base cannot validly point to an offset less than zero
1449 ??? IVOPTs creates bases that do not honor this restriction,
1450 so do not apply this optimization for TARGET_MEM_REFs. */
1451 if (TREE_CODE (base1
) != TARGET_MEM_REF
1452 && !ranges_maybe_overlap_p (offset1
+ moff
, -1, offset2
, max_size2
))
1454 /* They also cannot alias if the pointer may not point to the decl. */
1455 if (!ptr_deref_may_alias_decl_p (ptr1
, base2
))
1458 /* Disambiguations that rely on strict aliasing rules follow. */
1459 if (!flag_strict_aliasing
|| !tbaa_p
)
1462 ptrtype1
= TREE_TYPE (TREE_OPERAND (base1
, 1));
1464 /* If the alias set for a pointer access is zero all bets are off. */
1465 if (base1_alias_set
== 0)
1468 /* When we are trying to disambiguate an access with a pointer dereference
1469 as base versus one with a decl as base we can use both the size
1470 of the decl and its dynamic type for extra disambiguation.
1471 ??? We do not know anything about the dynamic type of the decl
1472 other than that its alias-set contains base2_alias_set as a subset
1473 which does not help us here. */
1474 /* As we know nothing useful about the dynamic type of the decl just
1475 use the usual conflict check rather than a subset test.
1476 ??? We could introduce -fvery-strict-aliasing when the language
1477 does not allow decls to have a dynamic type that differs from their
1478 static type. Then we can check
1479 !alias_set_subset_of (base1_alias_set, base2_alias_set) instead. */
1480 if (base1_alias_set
!= base2_alias_set
1481 && !alias_sets_conflict_p (base1_alias_set
, base2_alias_set
))
1483 /* If the size of the access relevant for TBAA through the pointer
1484 is bigger than the size of the decl we can't possibly access the
1485 decl via that pointer. */
1486 if (/* ??? This in turn may run afoul when a decl of type T which is
1487 a member of union type U is accessed through a pointer to
1488 type U and sizeof T is smaller than sizeof U. */
1489 TREE_CODE (TREE_TYPE (ptrtype1
)) != UNION_TYPE
1490 && TREE_CODE (TREE_TYPE (ptrtype1
)) != QUAL_UNION_TYPE
1491 && compare_sizes (DECL_SIZE (base2
),
1492 TYPE_SIZE (TREE_TYPE (ptrtype1
))) < 0)
1498 /* If the decl is accessed via a MEM_REF, reconstruct the base
1499 we can use for TBAA and an appropriately adjusted offset. */
1501 while (handled_component_p (dbase2
))
1502 dbase2
= TREE_OPERAND (dbase2
, 0);
1503 poly_int64 doffset1
= offset1
;
1504 poly_offset_int doffset2
= offset2
;
1505 if (TREE_CODE (dbase2
) == MEM_REF
1506 || TREE_CODE (dbase2
) == TARGET_MEM_REF
)
1508 doffset2
-= mem_ref_offset (dbase2
) << LOG2_BITS_PER_UNIT
;
1509 tree ptrtype2
= TREE_TYPE (TREE_OPERAND (dbase2
, 1));
1510 /* If second reference is view-converted, give up now. */
1511 if (same_type_for_tbaa (TREE_TYPE (dbase2
), TREE_TYPE (ptrtype2
)) != 1)
1515 /* If first reference is view-converted, give up now. */
1516 if (same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (ptrtype1
)) != 1)
1519 /* If both references are through the same type, they do not alias
1520 if the accesses do not overlap. This does extra disambiguation
1521 for mixed/pointer accesses but requires strict aliasing.
1522 For MEM_REFs we require that the component-ref offset we computed
1523 is relative to the start of the type which we ensure by
1524 comparing rvalue and access type and disregarding the constant
1527 But avoid treating variable length arrays as "objects", instead assume they
1528 can overlap by an exact multiple of their element size.
1529 See gcc.dg/torture/alias-2.c. */
1530 if (((TREE_CODE (base1
) != TARGET_MEM_REF
1531 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1532 && (TREE_CODE (dbase2
) != TARGET_MEM_REF
1533 || (!TMR_INDEX (dbase2
) && !TMR_INDEX2 (base2
))))
1534 && same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (dbase2
)) == 1
1535 && (TREE_CODE (TREE_TYPE (base1
)) != ARRAY_TYPE
1536 || (TYPE_SIZE (TREE_TYPE (base1
))
1537 && TREE_CODE (TYPE_SIZE (TREE_TYPE (base1
))) == INTEGER_CST
)))
1538 return ranges_maybe_overlap_p (doffset1
, max_size1
, doffset2
, max_size2
);
1541 && nonoverlapping_component_refs_p (ref1
, ref2
))
1544 /* Do access-path based disambiguation. */
1546 && (handled_component_p (ref1
) || handled_component_p (ref2
)))
1547 return aliasing_component_refs_p (ref1
,
1548 ref1_alias_set
, base1_alias_set
,
1551 ref2_alias_set
, base2_alias_set
,
1553 /* Only if the other reference is actual
1554 decl we can safely check only toplevel
1555 part of access path 1. */
1556 same_type_for_tbaa (TREE_TYPE (dbase2
),
1563 /* Return true if two indirect references based on *PTR1
1564 and *PTR2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and
1565 [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. *PTR1 and *PTR2 have
1566 the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1
1567 in which case they are computed on-demand. REF1 and REF2
1568 if non-NULL are the complete memory reference trees. */
1571 indirect_refs_may_alias_p (tree ref1 ATTRIBUTE_UNUSED
, tree base1
,
1572 poly_int64 offset1
, poly_int64 max_size1
,
1573 alias_set_type ref1_alias_set
,
1574 alias_set_type base1_alias_set
,
1575 tree ref2 ATTRIBUTE_UNUSED
, tree base2
,
1576 poly_int64 offset2
, poly_int64 max_size2
,
1577 alias_set_type ref2_alias_set
,
1578 alias_set_type base2_alias_set
, bool tbaa_p
)
1582 tree ptrtype1
, ptrtype2
;
1584 gcc_checking_assert ((TREE_CODE (base1
) == MEM_REF
1585 || TREE_CODE (base1
) == TARGET_MEM_REF
)
1586 && (TREE_CODE (base2
) == MEM_REF
1587 || TREE_CODE (base2
) == TARGET_MEM_REF
));
1589 ptr1
= TREE_OPERAND (base1
, 0);
1590 ptr2
= TREE_OPERAND (base2
, 0);
1592 /* If both bases are based on pointers they cannot alias if they may not
1593 point to the same memory object or if they point to the same object
1594 and the accesses do not overlap. */
1595 if ((!cfun
|| gimple_in_ssa_p (cfun
))
1596 && operand_equal_p (ptr1
, ptr2
, 0)
1597 && (((TREE_CODE (base1
) != TARGET_MEM_REF
1598 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1599 && (TREE_CODE (base2
) != TARGET_MEM_REF
1600 || (!TMR_INDEX (base2
) && !TMR_INDEX2 (base2
))))
1601 || (TREE_CODE (base1
) == TARGET_MEM_REF
1602 && TREE_CODE (base2
) == TARGET_MEM_REF
1603 && (TMR_STEP (base1
) == TMR_STEP (base2
)
1604 || (TMR_STEP (base1
) && TMR_STEP (base2
)
1605 && operand_equal_p (TMR_STEP (base1
),
1606 TMR_STEP (base2
), 0)))
1607 && (TMR_INDEX (base1
) == TMR_INDEX (base2
)
1608 || (TMR_INDEX (base1
) && TMR_INDEX (base2
)
1609 && operand_equal_p (TMR_INDEX (base1
),
1610 TMR_INDEX (base2
), 0)))
1611 && (TMR_INDEX2 (base1
) == TMR_INDEX2 (base2
)
1612 || (TMR_INDEX2 (base1
) && TMR_INDEX2 (base2
)
1613 && operand_equal_p (TMR_INDEX2 (base1
),
1614 TMR_INDEX2 (base2
), 0))))))
1616 poly_offset_int moff1
= mem_ref_offset (base1
) << LOG2_BITS_PER_UNIT
;
1617 poly_offset_int moff2
= mem_ref_offset (base2
) << LOG2_BITS_PER_UNIT
;
1618 return ranges_maybe_overlap_p (offset1
+ moff1
, max_size1
,
1619 offset2
+ moff2
, max_size2
);
1621 if (!ptr_derefs_may_alias_p (ptr1
, ptr2
))
1624 /* Disambiguations that rely on strict aliasing rules follow. */
1625 if (!flag_strict_aliasing
|| !tbaa_p
)
1628 ptrtype1
= TREE_TYPE (TREE_OPERAND (base1
, 1));
1629 ptrtype2
= TREE_TYPE (TREE_OPERAND (base2
, 1));
1631 /* If the alias set for a pointer access is zero all bets are off. */
1632 if (base1_alias_set
== 0
1633 || base2_alias_set
== 0)
1636 /* Do type-based disambiguation. */
1637 if (base1_alias_set
!= base2_alias_set
1638 && !alias_sets_conflict_p (base1_alias_set
, base2_alias_set
))
1641 /* If either reference is view-converted, give up now. */
1642 if (same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (ptrtype1
)) != 1
1643 || same_type_for_tbaa (TREE_TYPE (base2
), TREE_TYPE (ptrtype2
)) != 1)
1646 /* If both references are through the same type, they do not alias
1647 if the accesses do not overlap. This does extra disambiguation
1648 for mixed/pointer accesses but requires strict aliasing. */
1649 if ((TREE_CODE (base1
) != TARGET_MEM_REF
1650 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1651 && (TREE_CODE (base2
) != TARGET_MEM_REF
1652 || (!TMR_INDEX (base2
) && !TMR_INDEX2 (base2
)))
1653 && same_type_for_tbaa (TREE_TYPE (ptrtype1
),
1654 TREE_TYPE (ptrtype2
)) == 1
1655 /* But avoid treating arrays as "objects", instead assume they
1656 can overlap by an exact multiple of their element size.
1657 See gcc.dg/torture/alias-2.c. */
1658 && TREE_CODE (TREE_TYPE (ptrtype1
)) != ARRAY_TYPE
)
1659 return ranges_maybe_overlap_p (offset1
, max_size1
, offset2
, max_size2
);
1662 && nonoverlapping_component_refs_p (ref1
, ref2
))
1665 /* Do access-path based disambiguation. */
1667 && (handled_component_p (ref1
) || handled_component_p (ref2
)))
1668 return aliasing_component_refs_p (ref1
,
1669 ref1_alias_set
, base1_alias_set
,
1672 ref2_alias_set
, base2_alias_set
,
1673 offset2
, max_size2
, false);
1678 /* Return true, if the two memory references REF1 and REF2 may alias. */
1681 refs_may_alias_p_2 (ao_ref
*ref1
, ao_ref
*ref2
, bool tbaa_p
)
1684 poly_int64 offset1
= 0, offset2
= 0;
1685 poly_int64 max_size1
= -1, max_size2
= -1;
1686 bool var1_p
, var2_p
, ind1_p
, ind2_p
;
1688 gcc_checking_assert ((!ref1
->ref
1689 || TREE_CODE (ref1
->ref
) == SSA_NAME
1690 || DECL_P (ref1
->ref
)
1691 || TREE_CODE (ref1
->ref
) == STRING_CST
1692 || handled_component_p (ref1
->ref
)
1693 || TREE_CODE (ref1
->ref
) == MEM_REF
1694 || TREE_CODE (ref1
->ref
) == TARGET_MEM_REF
)
1696 || TREE_CODE (ref2
->ref
) == SSA_NAME
1697 || DECL_P (ref2
->ref
)
1698 || TREE_CODE (ref2
->ref
) == STRING_CST
1699 || handled_component_p (ref2
->ref
)
1700 || TREE_CODE (ref2
->ref
) == MEM_REF
1701 || TREE_CODE (ref2
->ref
) == TARGET_MEM_REF
));
1703 /* Decompose the references into their base objects and the access. */
1704 base1
= ao_ref_base (ref1
);
1705 offset1
= ref1
->offset
;
1706 max_size1
= ref1
->max_size
;
1707 base2
= ao_ref_base (ref2
);
1708 offset2
= ref2
->offset
;
1709 max_size2
= ref2
->max_size
;
1711 /* We can end up with registers or constants as bases for example from
1712 *D.1663_44 = VIEW_CONVERT_EXPR<struct DB_LSN>(__tmp$B0F64_59);
1713 which is seen as a struct copy. */
1714 if (TREE_CODE (base1
) == SSA_NAME
1715 || TREE_CODE (base1
) == CONST_DECL
1716 || TREE_CODE (base1
) == CONSTRUCTOR
1717 || TREE_CODE (base1
) == ADDR_EXPR
1718 || CONSTANT_CLASS_P (base1
)
1719 || TREE_CODE (base2
) == SSA_NAME
1720 || TREE_CODE (base2
) == CONST_DECL
1721 || TREE_CODE (base2
) == CONSTRUCTOR
1722 || TREE_CODE (base2
) == ADDR_EXPR
1723 || CONSTANT_CLASS_P (base2
))
1726 /* We can end up referring to code via function and label decls.
1727 As we likely do not properly track code aliases conservatively
1729 if (TREE_CODE (base1
) == FUNCTION_DECL
1730 || TREE_CODE (base1
) == LABEL_DECL
1731 || TREE_CODE (base2
) == FUNCTION_DECL
1732 || TREE_CODE (base2
) == LABEL_DECL
)
1735 /* Two volatile accesses always conflict. */
1736 if (ref1
->volatile_p
1737 && ref2
->volatile_p
)
1740 /* Defer to simple offset based disambiguation if we have
1741 references based on two decls. Do this before defering to
1742 TBAA to handle must-alias cases in conformance with the
1743 GCC extension of allowing type-punning through unions. */
1744 var1_p
= DECL_P (base1
);
1745 var2_p
= DECL_P (base2
);
1746 if (var1_p
&& var2_p
)
1747 return decl_refs_may_alias_p (ref1
->ref
, base1
, offset1
, max_size1
,
1748 ref2
->ref
, base2
, offset2
, max_size2
);
1750 /* Handle restrict based accesses.
1751 ??? ao_ref_base strips inner MEM_REF [&decl], recover from that
1753 tree rbase1
= base1
;
1754 tree rbase2
= base2
;
1759 while (handled_component_p (rbase1
))
1760 rbase1
= TREE_OPERAND (rbase1
, 0);
1766 while (handled_component_p (rbase2
))
1767 rbase2
= TREE_OPERAND (rbase2
, 0);
1769 if (rbase1
&& rbase2
1770 && (TREE_CODE (base1
) == MEM_REF
|| TREE_CODE (base1
) == TARGET_MEM_REF
)
1771 && (TREE_CODE (base2
) == MEM_REF
|| TREE_CODE (base2
) == TARGET_MEM_REF
)
1772 /* If the accesses are in the same restrict clique... */
1773 && MR_DEPENDENCE_CLIQUE (base1
) == MR_DEPENDENCE_CLIQUE (base2
)
1774 /* But based on different pointers they do not alias. */
1775 && MR_DEPENDENCE_BASE (base1
) != MR_DEPENDENCE_BASE (base2
))
1778 ind1_p
= (TREE_CODE (base1
) == MEM_REF
1779 || TREE_CODE (base1
) == TARGET_MEM_REF
);
1780 ind2_p
= (TREE_CODE (base2
) == MEM_REF
1781 || TREE_CODE (base2
) == TARGET_MEM_REF
);
1783 /* Canonicalize the pointer-vs-decl case. */
1784 if (ind1_p
&& var2_p
)
1786 std::swap (offset1
, offset2
);
1787 std::swap (max_size1
, max_size2
);
1788 std::swap (base1
, base2
);
1789 std::swap (ref1
, ref2
);
1796 /* First defer to TBAA if possible. */
1798 && flag_strict_aliasing
1799 && !alias_sets_conflict_p (ao_ref_alias_set (ref1
),
1800 ao_ref_alias_set (ref2
)))
1803 /* If the reference is based on a pointer that points to memory
1804 that may not be written to then the other reference cannot possibly
1806 if ((TREE_CODE (TREE_OPERAND (base2
, 0)) == SSA_NAME
1807 && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base2
, 0)))
1809 && TREE_CODE (TREE_OPERAND (base1
, 0)) == SSA_NAME
1810 && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base1
, 0))))
1813 /* Dispatch to the pointer-vs-decl or pointer-vs-pointer disambiguators. */
1814 if (var1_p
&& ind2_p
)
1815 return indirect_ref_may_alias_decl_p (ref2
->ref
, base2
,
1817 ao_ref_alias_set (ref2
),
1818 ao_ref_base_alias_set (ref2
),
1821 ao_ref_alias_set (ref1
),
1822 ao_ref_base_alias_set (ref1
),
1824 else if (ind1_p
&& ind2_p
)
1825 return indirect_refs_may_alias_p (ref1
->ref
, base1
,
1827 ao_ref_alias_set (ref1
),
1828 ao_ref_base_alias_set (ref1
),
1831 ao_ref_alias_set (ref2
),
1832 ao_ref_base_alias_set (ref2
),
1838 /* Return true, if the two memory references REF1 and REF2 may alias
1839 and update statistics. */
1842 refs_may_alias_p_1 (ao_ref
*ref1
, ao_ref
*ref2
, bool tbaa_p
)
1844 bool res
= refs_may_alias_p_2 (ref1
, ref2
, tbaa_p
);
1846 ++alias_stats
.refs_may_alias_p_may_alias
;
1848 ++alias_stats
.refs_may_alias_p_no_alias
;
1853 refs_may_alias_p (tree ref1
, ao_ref
*ref2
, bool tbaa_p
)
1856 ao_ref_init (&r1
, ref1
);
1857 return refs_may_alias_p_1 (&r1
, ref2
, tbaa_p
);
1861 refs_may_alias_p (tree ref1
, tree ref2
, bool tbaa_p
)
1864 ao_ref_init (&r1
, ref1
);
1865 ao_ref_init (&r2
, ref2
);
1866 return refs_may_alias_p_1 (&r1
, &r2
, tbaa_p
);
1869 /* Returns true if there is a anti-dependence for the STORE that
1870 executes after the LOAD. */
1873 refs_anti_dependent_p (tree load
, tree store
)
1876 ao_ref_init (&r1
, load
);
1877 ao_ref_init (&r2
, store
);
1878 return refs_may_alias_p_1 (&r1
, &r2
, false);
1881 /* Returns true if there is a output dependence for the stores
1882 STORE1 and STORE2. */
1885 refs_output_dependent_p (tree store1
, tree store2
)
1888 ao_ref_init (&r1
, store1
);
1889 ao_ref_init (&r2
, store2
);
1890 return refs_may_alias_p_1 (&r1
, &r2
, false);
1893 /* If the call CALL may use the memory reference REF return true,
1894 otherwise return false. */
1897 ref_maybe_used_by_call_p_1 (gcall
*call
, ao_ref
*ref
, bool tbaa_p
)
1901 int flags
= gimple_call_flags (call
);
1903 /* Const functions without a static chain do not implicitly use memory. */
1904 if (!gimple_call_chain (call
)
1905 && (flags
& (ECF_CONST
|ECF_NOVOPS
)))
1908 base
= ao_ref_base (ref
);
1912 /* A call that is not without side-effects might involve volatile
1913 accesses and thus conflicts with all other volatile accesses. */
1914 if (ref
->volatile_p
)
1917 /* If the reference is based on a decl that is not aliased the call
1918 cannot possibly use it. */
1920 && !may_be_aliased (base
)
1921 /* But local statics can be used through recursion. */
1922 && !is_global_var (base
))
1925 callee
= gimple_call_fndecl (call
);
1927 /* Handle those builtin functions explicitly that do not act as
1928 escape points. See tree-ssa-structalias.c:find_func_aliases
1929 for the list of builtins we might need to handle here. */
1930 if (callee
!= NULL_TREE
1931 && gimple_call_builtin_p (call
, BUILT_IN_NORMAL
))
1932 switch (DECL_FUNCTION_CODE (callee
))
1934 /* All the following functions read memory pointed to by
1935 their second argument. strcat/strncat additionally
1936 reads memory pointed to by the first argument. */
1937 case BUILT_IN_STRCAT
:
1938 case BUILT_IN_STRNCAT
:
1941 ao_ref_init_from_ptr_and_size (&dref
,
1942 gimple_call_arg (call
, 0),
1944 if (refs_may_alias_p_1 (&dref
, ref
, false))
1948 case BUILT_IN_STRCPY
:
1949 case BUILT_IN_STRNCPY
:
1950 case BUILT_IN_MEMCPY
:
1951 case BUILT_IN_MEMMOVE
:
1952 case BUILT_IN_MEMPCPY
:
1953 case BUILT_IN_STPCPY
:
1954 case BUILT_IN_STPNCPY
:
1955 case BUILT_IN_TM_MEMCPY
:
1956 case BUILT_IN_TM_MEMMOVE
:
1959 tree size
= NULL_TREE
;
1960 if (gimple_call_num_args (call
) == 3)
1961 size
= gimple_call_arg (call
, 2);
1962 ao_ref_init_from_ptr_and_size (&dref
,
1963 gimple_call_arg (call
, 1),
1965 return refs_may_alias_p_1 (&dref
, ref
, false);
1967 case BUILT_IN_STRCAT_CHK
:
1968 case BUILT_IN_STRNCAT_CHK
:
1971 ao_ref_init_from_ptr_and_size (&dref
,
1972 gimple_call_arg (call
, 0),
1974 if (refs_may_alias_p_1 (&dref
, ref
, false))
1978 case BUILT_IN_STRCPY_CHK
:
1979 case BUILT_IN_STRNCPY_CHK
:
1980 case BUILT_IN_MEMCPY_CHK
:
1981 case BUILT_IN_MEMMOVE_CHK
:
1982 case BUILT_IN_MEMPCPY_CHK
:
1983 case BUILT_IN_STPCPY_CHK
:
1984 case BUILT_IN_STPNCPY_CHK
:
1987 tree size
= NULL_TREE
;
1988 if (gimple_call_num_args (call
) == 4)
1989 size
= gimple_call_arg (call
, 2);
1990 ao_ref_init_from_ptr_and_size (&dref
,
1991 gimple_call_arg (call
, 1),
1993 return refs_may_alias_p_1 (&dref
, ref
, false);
1995 case BUILT_IN_BCOPY
:
1998 tree size
= gimple_call_arg (call
, 2);
1999 ao_ref_init_from_ptr_and_size (&dref
,
2000 gimple_call_arg (call
, 0),
2002 return refs_may_alias_p_1 (&dref
, ref
, false);
2005 /* The following functions read memory pointed to by their
2007 CASE_BUILT_IN_TM_LOAD (1):
2008 CASE_BUILT_IN_TM_LOAD (2):
2009 CASE_BUILT_IN_TM_LOAD (4):
2010 CASE_BUILT_IN_TM_LOAD (8):
2011 CASE_BUILT_IN_TM_LOAD (FLOAT
):
2012 CASE_BUILT_IN_TM_LOAD (DOUBLE
):
2013 CASE_BUILT_IN_TM_LOAD (LDOUBLE
):
2014 CASE_BUILT_IN_TM_LOAD (M64
):
2015 CASE_BUILT_IN_TM_LOAD (M128
):
2016 CASE_BUILT_IN_TM_LOAD (M256
):
2017 case BUILT_IN_TM_LOG
:
2018 case BUILT_IN_TM_LOG_1
:
2019 case BUILT_IN_TM_LOG_2
:
2020 case BUILT_IN_TM_LOG_4
:
2021 case BUILT_IN_TM_LOG_8
:
2022 case BUILT_IN_TM_LOG_FLOAT
:
2023 case BUILT_IN_TM_LOG_DOUBLE
:
2024 case BUILT_IN_TM_LOG_LDOUBLE
:
2025 case BUILT_IN_TM_LOG_M64
:
2026 case BUILT_IN_TM_LOG_M128
:
2027 case BUILT_IN_TM_LOG_M256
:
2028 return ptr_deref_may_alias_ref_p_1 (gimple_call_arg (call
, 0), ref
);
2030 /* These read memory pointed to by the first argument. */
2031 case BUILT_IN_STRDUP
:
2032 case BUILT_IN_STRNDUP
:
2033 case BUILT_IN_REALLOC
:
2036 tree size
= NULL_TREE
;
2037 if (gimple_call_num_args (call
) == 2)
2038 size
= gimple_call_arg (call
, 1);
2039 ao_ref_init_from_ptr_and_size (&dref
,
2040 gimple_call_arg (call
, 0),
2042 return refs_may_alias_p_1 (&dref
, ref
, false);
2044 /* These read memory pointed to by the first argument. */
2045 case BUILT_IN_INDEX
:
2046 case BUILT_IN_STRCHR
:
2047 case BUILT_IN_STRRCHR
:
2050 ao_ref_init_from_ptr_and_size (&dref
,
2051 gimple_call_arg (call
, 0),
2053 return refs_may_alias_p_1 (&dref
, ref
, false);
2055 /* These read memory pointed to by the first argument with size
2056 in the third argument. */
2057 case BUILT_IN_MEMCHR
:
2060 ao_ref_init_from_ptr_and_size (&dref
,
2061 gimple_call_arg (call
, 0),
2062 gimple_call_arg (call
, 2));
2063 return refs_may_alias_p_1 (&dref
, ref
, false);
2065 /* These read memory pointed to by the first and second arguments. */
2066 case BUILT_IN_STRSTR
:
2067 case BUILT_IN_STRPBRK
:
2070 ao_ref_init_from_ptr_and_size (&dref
,
2071 gimple_call_arg (call
, 0),
2073 if (refs_may_alias_p_1 (&dref
, ref
, false))
2075 ao_ref_init_from_ptr_and_size (&dref
,
2076 gimple_call_arg (call
, 1),
2078 return refs_may_alias_p_1 (&dref
, ref
, false);
2081 /* The following builtins do not read from memory. */
2083 case BUILT_IN_MALLOC
:
2084 case BUILT_IN_POSIX_MEMALIGN
:
2085 case BUILT_IN_ALIGNED_ALLOC
:
2086 case BUILT_IN_CALLOC
:
2087 CASE_BUILT_IN_ALLOCA
:
2088 case BUILT_IN_STACK_SAVE
:
2089 case BUILT_IN_STACK_RESTORE
:
2090 case BUILT_IN_MEMSET
:
2091 case BUILT_IN_TM_MEMSET
:
2092 case BUILT_IN_MEMSET_CHK
:
2093 case BUILT_IN_FREXP
:
2094 case BUILT_IN_FREXPF
:
2095 case BUILT_IN_FREXPL
:
2096 case BUILT_IN_GAMMA_R
:
2097 case BUILT_IN_GAMMAF_R
:
2098 case BUILT_IN_GAMMAL_R
:
2099 case BUILT_IN_LGAMMA_R
:
2100 case BUILT_IN_LGAMMAF_R
:
2101 case BUILT_IN_LGAMMAL_R
:
2103 case BUILT_IN_MODFF
:
2104 case BUILT_IN_MODFL
:
2105 case BUILT_IN_REMQUO
:
2106 case BUILT_IN_REMQUOF
:
2107 case BUILT_IN_REMQUOL
:
2108 case BUILT_IN_SINCOS
:
2109 case BUILT_IN_SINCOSF
:
2110 case BUILT_IN_SINCOSL
:
2111 case BUILT_IN_ASSUME_ALIGNED
:
2112 case BUILT_IN_VA_END
:
2114 /* __sync_* builtins and some OpenMP builtins act as threading
2116 #undef DEF_SYNC_BUILTIN
2117 #define DEF_SYNC_BUILTIN(ENUM, NAME, TYPE, ATTRS) case ENUM:
2118 #include "sync-builtins.def"
2119 #undef DEF_SYNC_BUILTIN
2120 case BUILT_IN_GOMP_ATOMIC_START
:
2121 case BUILT_IN_GOMP_ATOMIC_END
:
2122 case BUILT_IN_GOMP_BARRIER
:
2123 case BUILT_IN_GOMP_BARRIER_CANCEL
:
2124 case BUILT_IN_GOMP_TASKWAIT
:
2125 case BUILT_IN_GOMP_TASKGROUP_END
:
2126 case BUILT_IN_GOMP_CRITICAL_START
:
2127 case BUILT_IN_GOMP_CRITICAL_END
:
2128 case BUILT_IN_GOMP_CRITICAL_NAME_START
:
2129 case BUILT_IN_GOMP_CRITICAL_NAME_END
:
2130 case BUILT_IN_GOMP_LOOP_END
:
2131 case BUILT_IN_GOMP_LOOP_END_CANCEL
:
2132 case BUILT_IN_GOMP_ORDERED_START
:
2133 case BUILT_IN_GOMP_ORDERED_END
:
2134 case BUILT_IN_GOMP_SECTIONS_END
:
2135 case BUILT_IN_GOMP_SECTIONS_END_CANCEL
:
2136 case BUILT_IN_GOMP_SINGLE_COPY_START
:
2137 case BUILT_IN_GOMP_SINGLE_COPY_END
:
2141 /* Fallthru to general call handling. */;
2144 /* Check if base is a global static variable that is not read
2146 if (callee
!= NULL_TREE
&& VAR_P (base
) && TREE_STATIC (base
))
2148 struct cgraph_node
*node
= cgraph_node::get (callee
);
2151 /* FIXME: Callee can be an OMP builtin that does not have a call graph
2152 node yet. We should enforce that there are nodes for all decls in the
2153 IL and remove this check instead. */
2155 && (not_read
= ipa_reference_get_not_read_global (node
))
2156 && bitmap_bit_p (not_read
, ipa_reference_var_uid (base
)))
2160 /* Check if the base variable is call-used. */
2163 if (pt_solution_includes (gimple_call_use_set (call
), base
))
2166 else if ((TREE_CODE (base
) == MEM_REF
2167 || TREE_CODE (base
) == TARGET_MEM_REF
)
2168 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
)
2170 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (TREE_OPERAND (base
, 0));
2174 if (pt_solutions_intersect (gimple_call_use_set (call
), &pi
->pt
))
2180 /* Inspect call arguments for passed-by-value aliases. */
2182 for (i
= 0; i
< gimple_call_num_args (call
); ++i
)
2184 tree op
= gimple_call_arg (call
, i
);
2185 int flags
= gimple_call_arg_flags (call
, i
);
2187 if (flags
& EAF_UNUSED
)
2190 if (TREE_CODE (op
) == WITH_SIZE_EXPR
)
2191 op
= TREE_OPERAND (op
, 0);
2193 if (TREE_CODE (op
) != SSA_NAME
2194 && !is_gimple_min_invariant (op
))
2197 ao_ref_init (&r
, op
);
2198 if (refs_may_alias_p_1 (&r
, ref
, tbaa_p
))
2207 ref_maybe_used_by_call_p (gcall
*call
, ao_ref
*ref
, bool tbaa_p
)
2210 res
= ref_maybe_used_by_call_p_1 (call
, ref
, tbaa_p
);
2212 ++alias_stats
.ref_maybe_used_by_call_p_may_alias
;
2214 ++alias_stats
.ref_maybe_used_by_call_p_no_alias
;
2219 /* If the statement STMT may use the memory reference REF return
2220 true, otherwise return false. */
2223 ref_maybe_used_by_stmt_p (gimple
*stmt
, ao_ref
*ref
, bool tbaa_p
)
2225 if (is_gimple_assign (stmt
))
2229 /* All memory assign statements are single. */
2230 if (!gimple_assign_single_p (stmt
))
2233 rhs
= gimple_assign_rhs1 (stmt
);
2234 if (is_gimple_reg (rhs
)
2235 || is_gimple_min_invariant (rhs
)
2236 || gimple_assign_rhs_code (stmt
) == CONSTRUCTOR
)
2239 return refs_may_alias_p (rhs
, ref
, tbaa_p
);
2241 else if (is_gimple_call (stmt
))
2242 return ref_maybe_used_by_call_p (as_a
<gcall
*> (stmt
), ref
, tbaa_p
);
2243 else if (greturn
*return_stmt
= dyn_cast
<greturn
*> (stmt
))
2245 tree retval
= gimple_return_retval (return_stmt
);
2247 && TREE_CODE (retval
) != SSA_NAME
2248 && !is_gimple_min_invariant (retval
)
2249 && refs_may_alias_p (retval
, ref
, tbaa_p
))
2251 /* If ref escapes the function then the return acts as a use. */
2252 tree base
= ao_ref_base (ref
);
2255 else if (DECL_P (base
))
2256 return is_global_var (base
);
2257 else if (TREE_CODE (base
) == MEM_REF
2258 || TREE_CODE (base
) == TARGET_MEM_REF
)
2259 return ptr_deref_may_alias_global_p (TREE_OPERAND (base
, 0));
2267 ref_maybe_used_by_stmt_p (gimple
*stmt
, tree ref
, bool tbaa_p
)
2270 ao_ref_init (&r
, ref
);
2271 return ref_maybe_used_by_stmt_p (stmt
, &r
, tbaa_p
);
2274 /* If the call in statement CALL may clobber the memory reference REF
2275 return true, otherwise return false. */
2278 call_may_clobber_ref_p_1 (gcall
*call
, ao_ref
*ref
)
2283 /* If the call is pure or const it cannot clobber anything. */
2284 if (gimple_call_flags (call
)
2285 & (ECF_PURE
|ECF_CONST
|ECF_LOOPING_CONST_OR_PURE
|ECF_NOVOPS
))
2287 if (gimple_call_internal_p (call
))
2288 switch (gimple_call_internal_fn (call
))
2290 /* Treat these internal calls like ECF_PURE for aliasing,
2291 they don't write to any memory the program should care about.
2292 They have important other side-effects, and read memory,
2293 so can't be ECF_NOVOPS. */
2294 case IFN_UBSAN_NULL
:
2295 case IFN_UBSAN_BOUNDS
:
2296 case IFN_UBSAN_VPTR
:
2297 case IFN_UBSAN_OBJECT_SIZE
:
2299 case IFN_ASAN_CHECK
:
2305 base
= ao_ref_base (ref
);
2309 if (TREE_CODE (base
) == SSA_NAME
2310 || CONSTANT_CLASS_P (base
))
2313 /* A call that is not without side-effects might involve volatile
2314 accesses and thus conflicts with all other volatile accesses. */
2315 if (ref
->volatile_p
)
2318 /* If the reference is based on a decl that is not aliased the call
2319 cannot possibly clobber it. */
2321 && !may_be_aliased (base
)
2322 /* But local non-readonly statics can be modified through recursion
2323 or the call may implement a threading barrier which we must
2324 treat as may-def. */
2325 && (TREE_READONLY (base
)
2326 || !is_global_var (base
)))
2329 /* If the reference is based on a pointer that points to memory
2330 that may not be written to then the call cannot possibly clobber it. */
2331 if ((TREE_CODE (base
) == MEM_REF
2332 || TREE_CODE (base
) == TARGET_MEM_REF
)
2333 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
2334 && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base
, 0)))
2337 callee
= gimple_call_fndecl (call
);
2339 /* Handle those builtin functions explicitly that do not act as
2340 escape points. See tree-ssa-structalias.c:find_func_aliases
2341 for the list of builtins we might need to handle here. */
2342 if (callee
!= NULL_TREE
2343 && gimple_call_builtin_p (call
, BUILT_IN_NORMAL
))
2344 switch (DECL_FUNCTION_CODE (callee
))
2346 /* All the following functions clobber memory pointed to by
2347 their first argument. */
2348 case BUILT_IN_STRCPY
:
2349 case BUILT_IN_STRNCPY
:
2350 case BUILT_IN_MEMCPY
:
2351 case BUILT_IN_MEMMOVE
:
2352 case BUILT_IN_MEMPCPY
:
2353 case BUILT_IN_STPCPY
:
2354 case BUILT_IN_STPNCPY
:
2355 case BUILT_IN_STRCAT
:
2356 case BUILT_IN_STRNCAT
:
2357 case BUILT_IN_MEMSET
:
2358 case BUILT_IN_TM_MEMSET
:
2359 CASE_BUILT_IN_TM_STORE (1):
2360 CASE_BUILT_IN_TM_STORE (2):
2361 CASE_BUILT_IN_TM_STORE (4):
2362 CASE_BUILT_IN_TM_STORE (8):
2363 CASE_BUILT_IN_TM_STORE (FLOAT
):
2364 CASE_BUILT_IN_TM_STORE (DOUBLE
):
2365 CASE_BUILT_IN_TM_STORE (LDOUBLE
):
2366 CASE_BUILT_IN_TM_STORE (M64
):
2367 CASE_BUILT_IN_TM_STORE (M128
):
2368 CASE_BUILT_IN_TM_STORE (M256
):
2369 case BUILT_IN_TM_MEMCPY
:
2370 case BUILT_IN_TM_MEMMOVE
:
2373 tree size
= NULL_TREE
;
2374 /* Don't pass in size for strncat, as the maximum size
2375 is strlen (dest) + n + 1 instead of n, resp.
2376 n + 1 at dest + strlen (dest), but strlen (dest) isn't
2378 if (gimple_call_num_args (call
) == 3
2379 && DECL_FUNCTION_CODE (callee
) != BUILT_IN_STRNCAT
)
2380 size
= gimple_call_arg (call
, 2);
2381 ao_ref_init_from_ptr_and_size (&dref
,
2382 gimple_call_arg (call
, 0),
2384 return refs_may_alias_p_1 (&dref
, ref
, false);
2386 case BUILT_IN_STRCPY_CHK
:
2387 case BUILT_IN_STRNCPY_CHK
:
2388 case BUILT_IN_MEMCPY_CHK
:
2389 case BUILT_IN_MEMMOVE_CHK
:
2390 case BUILT_IN_MEMPCPY_CHK
:
2391 case BUILT_IN_STPCPY_CHK
:
2392 case BUILT_IN_STPNCPY_CHK
:
2393 case BUILT_IN_STRCAT_CHK
:
2394 case BUILT_IN_STRNCAT_CHK
:
2395 case BUILT_IN_MEMSET_CHK
:
2398 tree size
= NULL_TREE
;
2399 /* Don't pass in size for __strncat_chk, as the maximum size
2400 is strlen (dest) + n + 1 instead of n, resp.
2401 n + 1 at dest + strlen (dest), but strlen (dest) isn't
2403 if (gimple_call_num_args (call
) == 4
2404 && DECL_FUNCTION_CODE (callee
) != BUILT_IN_STRNCAT_CHK
)
2405 size
= gimple_call_arg (call
, 2);
2406 ao_ref_init_from_ptr_and_size (&dref
,
2407 gimple_call_arg (call
, 0),
2409 return refs_may_alias_p_1 (&dref
, ref
, false);
2411 case BUILT_IN_BCOPY
:
2414 tree size
= gimple_call_arg (call
, 2);
2415 ao_ref_init_from_ptr_and_size (&dref
,
2416 gimple_call_arg (call
, 1),
2418 return refs_may_alias_p_1 (&dref
, ref
, false);
2420 /* Allocating memory does not have any side-effects apart from
2421 being the definition point for the pointer. */
2422 case BUILT_IN_MALLOC
:
2423 case BUILT_IN_ALIGNED_ALLOC
:
2424 case BUILT_IN_CALLOC
:
2425 case BUILT_IN_STRDUP
:
2426 case BUILT_IN_STRNDUP
:
2427 /* Unix98 specifies that errno is set on allocation failure. */
2429 && targetm
.ref_may_alias_errno (ref
))
2432 case BUILT_IN_STACK_SAVE
:
2433 CASE_BUILT_IN_ALLOCA
:
2434 case BUILT_IN_ASSUME_ALIGNED
:
2436 /* But posix_memalign stores a pointer into the memory pointed to
2437 by its first argument. */
2438 case BUILT_IN_POSIX_MEMALIGN
:
2440 tree ptrptr
= gimple_call_arg (call
, 0);
2442 ao_ref_init_from_ptr_and_size (&dref
, ptrptr
,
2443 TYPE_SIZE_UNIT (ptr_type_node
));
2444 return (refs_may_alias_p_1 (&dref
, ref
, false)
2446 && targetm
.ref_may_alias_errno (ref
)));
2448 /* Freeing memory kills the pointed-to memory. More importantly
2449 the call has to serve as a barrier for moving loads and stores
2452 case BUILT_IN_VA_END
:
2454 tree ptr
= gimple_call_arg (call
, 0);
2455 return ptr_deref_may_alias_ref_p_1 (ptr
, ref
);
2457 /* Realloc serves both as allocation point and deallocation point. */
2458 case BUILT_IN_REALLOC
:
2460 tree ptr
= gimple_call_arg (call
, 0);
2461 /* Unix98 specifies that errno is set on allocation failure. */
2462 return ((flag_errno_math
2463 && targetm
.ref_may_alias_errno (ref
))
2464 || ptr_deref_may_alias_ref_p_1 (ptr
, ref
));
2466 case BUILT_IN_GAMMA_R
:
2467 case BUILT_IN_GAMMAF_R
:
2468 case BUILT_IN_GAMMAL_R
:
2469 case BUILT_IN_LGAMMA_R
:
2470 case BUILT_IN_LGAMMAF_R
:
2471 case BUILT_IN_LGAMMAL_R
:
2473 tree out
= gimple_call_arg (call
, 1);
2474 if (ptr_deref_may_alias_ref_p_1 (out
, ref
))
2476 if (flag_errno_math
)
2480 case BUILT_IN_FREXP
:
2481 case BUILT_IN_FREXPF
:
2482 case BUILT_IN_FREXPL
:
2484 case BUILT_IN_MODFF
:
2485 case BUILT_IN_MODFL
:
2487 tree out
= gimple_call_arg (call
, 1);
2488 return ptr_deref_may_alias_ref_p_1 (out
, ref
);
2490 case BUILT_IN_REMQUO
:
2491 case BUILT_IN_REMQUOF
:
2492 case BUILT_IN_REMQUOL
:
2494 tree out
= gimple_call_arg (call
, 2);
2495 if (ptr_deref_may_alias_ref_p_1 (out
, ref
))
2497 if (flag_errno_math
)
2501 case BUILT_IN_SINCOS
:
2502 case BUILT_IN_SINCOSF
:
2503 case BUILT_IN_SINCOSL
:
2505 tree sin
= gimple_call_arg (call
, 1);
2506 tree cos
= gimple_call_arg (call
, 2);
2507 return (ptr_deref_may_alias_ref_p_1 (sin
, ref
)
2508 || ptr_deref_may_alias_ref_p_1 (cos
, ref
));
2510 /* __sync_* builtins and some OpenMP builtins act as threading
2512 #undef DEF_SYNC_BUILTIN
2513 #define DEF_SYNC_BUILTIN(ENUM, NAME, TYPE, ATTRS) case ENUM:
2514 #include "sync-builtins.def"
2515 #undef DEF_SYNC_BUILTIN
2516 case BUILT_IN_GOMP_ATOMIC_START
:
2517 case BUILT_IN_GOMP_ATOMIC_END
:
2518 case BUILT_IN_GOMP_BARRIER
:
2519 case BUILT_IN_GOMP_BARRIER_CANCEL
:
2520 case BUILT_IN_GOMP_TASKWAIT
:
2521 case BUILT_IN_GOMP_TASKGROUP_END
:
2522 case BUILT_IN_GOMP_CRITICAL_START
:
2523 case BUILT_IN_GOMP_CRITICAL_END
:
2524 case BUILT_IN_GOMP_CRITICAL_NAME_START
:
2525 case BUILT_IN_GOMP_CRITICAL_NAME_END
:
2526 case BUILT_IN_GOMP_LOOP_END
:
2527 case BUILT_IN_GOMP_LOOP_END_CANCEL
:
2528 case BUILT_IN_GOMP_ORDERED_START
:
2529 case BUILT_IN_GOMP_ORDERED_END
:
2530 case BUILT_IN_GOMP_SECTIONS_END
:
2531 case BUILT_IN_GOMP_SECTIONS_END_CANCEL
:
2532 case BUILT_IN_GOMP_SINGLE_COPY_START
:
2533 case BUILT_IN_GOMP_SINGLE_COPY_END
:
2536 /* Fallthru to general call handling. */;
2539 /* Check if base is a global static variable that is not written
2541 if (callee
!= NULL_TREE
&& VAR_P (base
) && TREE_STATIC (base
))
2543 struct cgraph_node
*node
= cgraph_node::get (callee
);
2547 && (not_written
= ipa_reference_get_not_written_global (node
))
2548 && bitmap_bit_p (not_written
, ipa_reference_var_uid (base
)))
2552 /* Check if the base variable is call-clobbered. */
2554 return pt_solution_includes (gimple_call_clobber_set (call
), base
);
2555 else if ((TREE_CODE (base
) == MEM_REF
2556 || TREE_CODE (base
) == TARGET_MEM_REF
)
2557 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
)
2559 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (TREE_OPERAND (base
, 0));
2563 return pt_solutions_intersect (gimple_call_clobber_set (call
), &pi
->pt
);
2569 /* If the call in statement CALL may clobber the memory reference REF
2570 return true, otherwise return false. */
2573 call_may_clobber_ref_p (gcall
*call
, tree ref
)
2577 ao_ref_init (&r
, ref
);
2578 res
= call_may_clobber_ref_p_1 (call
, &r
);
2580 ++alias_stats
.call_may_clobber_ref_p_may_alias
;
2582 ++alias_stats
.call_may_clobber_ref_p_no_alias
;
2587 /* If the statement STMT may clobber the memory reference REF return true,
2588 otherwise return false. */
2591 stmt_may_clobber_ref_p_1 (gimple
*stmt
, ao_ref
*ref
, bool tbaa_p
)
2593 if (is_gimple_call (stmt
))
2595 tree lhs
= gimple_call_lhs (stmt
);
2597 && TREE_CODE (lhs
) != SSA_NAME
)
2600 ao_ref_init (&r
, lhs
);
2601 if (refs_may_alias_p_1 (ref
, &r
, tbaa_p
))
2605 return call_may_clobber_ref_p_1 (as_a
<gcall
*> (stmt
), ref
);
2607 else if (gimple_assign_single_p (stmt
))
2609 tree lhs
= gimple_assign_lhs (stmt
);
2610 if (TREE_CODE (lhs
) != SSA_NAME
)
2613 ao_ref_init (&r
, lhs
);
2614 return refs_may_alias_p_1 (ref
, &r
, tbaa_p
);
2617 else if (gimple_code (stmt
) == GIMPLE_ASM
)
2624 stmt_may_clobber_ref_p (gimple
*stmt
, tree ref
, bool tbaa_p
)
2627 ao_ref_init (&r
, ref
);
2628 return stmt_may_clobber_ref_p_1 (stmt
, &r
, tbaa_p
);
2631 /* Return true if store1 and store2 described by corresponding tuples
2632 <BASE, OFFSET, SIZE, MAX_SIZE> have the same size and store to the same
2636 same_addr_size_stores_p (tree base1
, poly_int64 offset1
, poly_int64 size1
,
2637 poly_int64 max_size1
,
2638 tree base2
, poly_int64 offset2
, poly_int64 size2
,
2639 poly_int64 max_size2
)
2641 /* Offsets need to be 0. */
2642 if (maybe_ne (offset1
, 0)
2643 || maybe_ne (offset2
, 0))
2646 bool base1_obj_p
= SSA_VAR_P (base1
);
2647 bool base2_obj_p
= SSA_VAR_P (base2
);
2649 /* We need one object. */
2650 if (base1_obj_p
== base2_obj_p
)
2652 tree obj
= base1_obj_p
? base1
: base2
;
2654 /* And we need one MEM_REF. */
2655 bool base1_memref_p
= TREE_CODE (base1
) == MEM_REF
;
2656 bool base2_memref_p
= TREE_CODE (base2
) == MEM_REF
;
2657 if (base1_memref_p
== base2_memref_p
)
2659 tree memref
= base1_memref_p
? base1
: base2
;
2661 /* Sizes need to be valid. */
2662 if (!known_size_p (max_size1
)
2663 || !known_size_p (max_size2
)
2664 || !known_size_p (size1
)
2665 || !known_size_p (size2
))
2668 /* Max_size needs to match size. */
2669 if (maybe_ne (max_size1
, size1
)
2670 || maybe_ne (max_size2
, size2
))
2673 /* Sizes need to match. */
2674 if (maybe_ne (size1
, size2
))
2678 /* Check that memref is a store to pointer with singleton points-to info. */
2679 if (!integer_zerop (TREE_OPERAND (memref
, 1)))
2681 tree ptr
= TREE_OPERAND (memref
, 0);
2682 if (TREE_CODE (ptr
) != SSA_NAME
)
2684 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (ptr
);
2685 unsigned int pt_uid
;
2687 || !pt_solution_singleton_or_null_p (&pi
->pt
, &pt_uid
))
2690 /* Be conservative with non-call exceptions when the address might
2692 if (cfun
->can_throw_non_call_exceptions
&& pi
->pt
.null
)
2695 /* Check that ptr points relative to obj. */
2696 unsigned int obj_uid
= DECL_PT_UID (obj
);
2697 if (obj_uid
!= pt_uid
)
2700 /* Check that the object size is the same as the store size. That ensures us
2701 that ptr points to the start of obj. */
2702 return (DECL_SIZE (obj
)
2703 && poly_int_tree_p (DECL_SIZE (obj
))
2704 && known_eq (wi::to_poly_offset (DECL_SIZE (obj
)), size1
));
2707 /* If STMT kills the memory reference REF return true, otherwise
2711 stmt_kills_ref_p (gimple
*stmt
, ao_ref
*ref
)
2713 if (!ao_ref_base (ref
))
2716 if (gimple_has_lhs (stmt
)
2717 && TREE_CODE (gimple_get_lhs (stmt
)) != SSA_NAME
2718 /* The assignment is not necessarily carried out if it can throw
2719 and we can catch it in the current function where we could inspect
2721 ??? We only need to care about the RHS throwing. For aggregate
2722 assignments or similar calls and non-call exceptions the LHS
2723 might throw as well. */
2724 && !stmt_can_throw_internal (cfun
, stmt
))
2726 tree lhs
= gimple_get_lhs (stmt
);
2727 /* If LHS is literally a base of the access we are done. */
2730 tree base
= ref
->ref
;
2731 tree innermost_dropped_array_ref
= NULL_TREE
;
2732 if (handled_component_p (base
))
2734 tree saved_lhs0
= NULL_TREE
;
2735 if (handled_component_p (lhs
))
2737 saved_lhs0
= TREE_OPERAND (lhs
, 0);
2738 TREE_OPERAND (lhs
, 0) = integer_zero_node
;
2742 /* Just compare the outermost handled component, if
2743 they are equal we have found a possible common
2745 tree saved_base0
= TREE_OPERAND (base
, 0);
2746 TREE_OPERAND (base
, 0) = integer_zero_node
;
2747 bool res
= operand_equal_p (lhs
, base
, 0);
2748 TREE_OPERAND (base
, 0) = saved_base0
;
2751 /* Remember if we drop an array-ref that we need to
2752 double-check not being at struct end. */
2753 if (TREE_CODE (base
) == ARRAY_REF
2754 || TREE_CODE (base
) == ARRAY_RANGE_REF
)
2755 innermost_dropped_array_ref
= base
;
2756 /* Otherwise drop handled components of the access. */
2759 while (handled_component_p (base
));
2761 TREE_OPERAND (lhs
, 0) = saved_lhs0
;
2763 /* Finally check if the lhs has the same address and size as the
2764 base candidate of the access. Watch out if we have dropped
2765 an array-ref that was at struct end, this means ref->ref may
2766 be outside of the TYPE_SIZE of its base. */
2767 if ((! innermost_dropped_array_ref
2768 || ! array_at_struct_end_p (innermost_dropped_array_ref
))
2770 || (((TYPE_SIZE (TREE_TYPE (lhs
))
2771 == TYPE_SIZE (TREE_TYPE (base
)))
2772 || (TYPE_SIZE (TREE_TYPE (lhs
))
2773 && TYPE_SIZE (TREE_TYPE (base
))
2774 && operand_equal_p (TYPE_SIZE (TREE_TYPE (lhs
)),
2775 TYPE_SIZE (TREE_TYPE (base
)),
2777 && operand_equal_p (lhs
, base
,
2779 | OEP_MATCH_SIDE_EFFECTS
))))
2783 /* Now look for non-literal equal bases with the restriction of
2784 handling constant offset and size. */
2785 /* For a must-alias check we need to be able to constrain
2786 the access properly. */
2787 if (!ref
->max_size_known_p ())
2789 poly_int64 size
, offset
, max_size
, ref_offset
= ref
->offset
;
2791 tree base
= get_ref_base_and_extent (lhs
, &offset
, &size
, &max_size
,
2793 /* We can get MEM[symbol: sZ, index: D.8862_1] here,
2794 so base == ref->base does not always hold. */
2795 if (base
!= ref
->base
)
2797 /* Try using points-to info. */
2798 if (same_addr_size_stores_p (base
, offset
, size
, max_size
, ref
->base
,
2799 ref
->offset
, ref
->size
, ref
->max_size
))
2802 /* If both base and ref->base are MEM_REFs, only compare the
2803 first operand, and if the second operand isn't equal constant,
2804 try to add the offsets into offset and ref_offset. */
2805 if (TREE_CODE (base
) == MEM_REF
&& TREE_CODE (ref
->base
) == MEM_REF
2806 && TREE_OPERAND (base
, 0) == TREE_OPERAND (ref
->base
, 0))
2808 if (!tree_int_cst_equal (TREE_OPERAND (base
, 1),
2809 TREE_OPERAND (ref
->base
, 1)))
2811 poly_offset_int off1
= mem_ref_offset (base
);
2812 off1
<<= LOG2_BITS_PER_UNIT
;
2814 poly_offset_int off2
= mem_ref_offset (ref
->base
);
2815 off2
<<= LOG2_BITS_PER_UNIT
;
2817 if (!off1
.to_shwi (&offset
) || !off2
.to_shwi (&ref_offset
))
2824 /* For a must-alias check we need to be able to constrain
2825 the access properly. */
2826 if (known_eq (size
, max_size
)
2827 && known_subrange_p (ref_offset
, ref
->max_size
, offset
, size
))
2831 if (is_gimple_call (stmt
))
2833 tree callee
= gimple_call_fndecl (stmt
);
2834 if (callee
!= NULL_TREE
2835 && gimple_call_builtin_p (stmt
, BUILT_IN_NORMAL
))
2836 switch (DECL_FUNCTION_CODE (callee
))
2840 tree ptr
= gimple_call_arg (stmt
, 0);
2841 tree base
= ao_ref_base (ref
);
2842 if (base
&& TREE_CODE (base
) == MEM_REF
2843 && TREE_OPERAND (base
, 0) == ptr
)
2848 case BUILT_IN_MEMCPY
:
2849 case BUILT_IN_MEMPCPY
:
2850 case BUILT_IN_MEMMOVE
:
2851 case BUILT_IN_MEMSET
:
2852 case BUILT_IN_MEMCPY_CHK
:
2853 case BUILT_IN_MEMPCPY_CHK
:
2854 case BUILT_IN_MEMMOVE_CHK
:
2855 case BUILT_IN_MEMSET_CHK
:
2856 case BUILT_IN_STRNCPY
:
2857 case BUILT_IN_STPNCPY
:
2859 /* For a must-alias check we need to be able to constrain
2860 the access properly. */
2861 if (!ref
->max_size_known_p ())
2863 tree dest
= gimple_call_arg (stmt
, 0);
2864 tree len
= gimple_call_arg (stmt
, 2);
2865 if (!poly_int_tree_p (len
))
2867 tree rbase
= ref
->base
;
2868 poly_offset_int roffset
= ref
->offset
;
2870 ao_ref_init_from_ptr_and_size (&dref
, dest
, len
);
2871 tree base
= ao_ref_base (&dref
);
2872 poly_offset_int offset
= dref
.offset
;
2873 if (!base
|| !known_size_p (dref
.size
))
2875 if (TREE_CODE (base
) == MEM_REF
)
2877 if (TREE_CODE (rbase
) != MEM_REF
)
2879 // Compare pointers.
2880 offset
+= mem_ref_offset (base
) << LOG2_BITS_PER_UNIT
;
2881 roffset
+= mem_ref_offset (rbase
) << LOG2_BITS_PER_UNIT
;
2882 base
= TREE_OPERAND (base
, 0);
2883 rbase
= TREE_OPERAND (rbase
, 0);
2886 && known_subrange_p (roffset
, ref
->max_size
, offset
,
2887 wi::to_poly_offset (len
)
2888 << LOG2_BITS_PER_UNIT
))
2893 case BUILT_IN_VA_END
:
2895 tree ptr
= gimple_call_arg (stmt
, 0);
2896 if (TREE_CODE (ptr
) == ADDR_EXPR
)
2898 tree base
= ao_ref_base (ref
);
2899 if (TREE_OPERAND (ptr
, 0) == base
)
2912 stmt_kills_ref_p (gimple
*stmt
, tree ref
)
2915 ao_ref_init (&r
, ref
);
2916 return stmt_kills_ref_p (stmt
, &r
);
2920 /* Walk the virtual use-def chain of VUSE until hitting the virtual operand
2921 TARGET or a statement clobbering the memory reference REF in which
2922 case false is returned. The walk starts with VUSE, one argument of PHI. */
2925 maybe_skip_until (gimple
*phi
, tree
&target
, basic_block target_bb
,
2926 ao_ref
*ref
, tree vuse
, unsigned int &limit
, bitmap
*visited
,
2927 bool abort_on_visited
,
2928 void *(*translate
)(ao_ref
*, tree
, void *, bool *),
2931 basic_block bb
= gimple_bb (phi
);
2934 *visited
= BITMAP_ALLOC (NULL
);
2936 bitmap_set_bit (*visited
, SSA_NAME_VERSION (PHI_RESULT (phi
)));
2938 /* Walk until we hit the target. */
2939 while (vuse
!= target
)
2941 gimple
*def_stmt
= SSA_NAME_DEF_STMT (vuse
);
2942 /* If we are searching for the target VUSE by walking up to
2943 TARGET_BB dominating the original PHI we are finished once
2944 we reach a default def or a definition in a block dominating
2945 that block. Update TARGET and return. */
2947 && (gimple_nop_p (def_stmt
)
2948 || dominated_by_p (CDI_DOMINATORS
,
2949 target_bb
, gimple_bb (def_stmt
))))
2955 /* Recurse for PHI nodes. */
2956 if (gimple_code (def_stmt
) == GIMPLE_PHI
)
2958 /* An already visited PHI node ends the walk successfully. */
2959 if (bitmap_bit_p (*visited
, SSA_NAME_VERSION (PHI_RESULT (def_stmt
))))
2960 return !abort_on_visited
;
2961 vuse
= get_continuation_for_phi (def_stmt
, ref
, limit
,
2962 visited
, abort_on_visited
,
2968 else if (gimple_nop_p (def_stmt
))
2972 /* A clobbering statement or the end of the IL ends it failing. */
2973 if ((int)limit
<= 0)
2976 if (stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
2978 bool disambiguate_only
= true;
2980 && (*translate
) (ref
, vuse
, data
, &disambiguate_only
) == NULL
)
2986 /* If we reach a new basic-block see if we already skipped it
2987 in a previous walk that ended successfully. */
2988 if (gimple_bb (def_stmt
) != bb
)
2990 if (!bitmap_set_bit (*visited
, SSA_NAME_VERSION (vuse
)))
2991 return !abort_on_visited
;
2992 bb
= gimple_bb (def_stmt
);
2994 vuse
= gimple_vuse (def_stmt
);
3000 /* Starting from a PHI node for the virtual operand of the memory reference
3001 REF find a continuation virtual operand that allows to continue walking
3002 statements dominating PHI skipping only statements that cannot possibly
3003 clobber REF. Decrements LIMIT for each alias disambiguation done
3004 and aborts the walk, returning NULL_TREE if it reaches zero.
3005 Returns NULL_TREE if no suitable virtual operand can be found. */
3008 get_continuation_for_phi (gimple
*phi
, ao_ref
*ref
,
3009 unsigned int &limit
, bitmap
*visited
,
3010 bool abort_on_visited
,
3011 void *(*translate
)(ao_ref
*, tree
, void *, bool *),
3014 unsigned nargs
= gimple_phi_num_args (phi
);
3016 /* Through a single-argument PHI we can simply look through. */
3018 return PHI_ARG_DEF (phi
, 0);
3020 /* For two or more arguments try to pairwise skip non-aliasing code
3021 until we hit the phi argument definition that dominates the other one. */
3022 basic_block phi_bb
= gimple_bb (phi
);
3026 /* Find a candidate for the virtual operand which definition
3027 dominates those of all others. */
3028 /* First look if any of the args themselves satisfy this. */
3029 for (i
= 0; i
< nargs
; ++i
)
3031 arg0
= PHI_ARG_DEF (phi
, i
);
3032 if (SSA_NAME_IS_DEFAULT_DEF (arg0
))
3034 basic_block def_bb
= gimple_bb (SSA_NAME_DEF_STMT (arg0
));
3035 if (def_bb
!= phi_bb
3036 && dominated_by_p (CDI_DOMINATORS
, phi_bb
, def_bb
))
3040 /* If not, look if we can reach such candidate by walking defs
3041 until we hit the immediate dominator. maybe_skip_until will
3043 basic_block dom
= get_immediate_dominator (CDI_DOMINATORS
, phi_bb
);
3045 /* Then check against the (to be) found candidate. */
3046 for (i
= 0; i
< nargs
; ++i
)
3048 arg1
= PHI_ARG_DEF (phi
, i
);
3051 else if (! maybe_skip_until (phi
, arg0
, dom
, ref
, arg1
, limit
, visited
,
3053 /* Do not translate when walking over
3057 gimple_bb (SSA_NAME_DEF_STMT (arg1
)),
3059 ? NULL
: translate
, data
))
3066 /* Based on the memory reference REF and its virtual use VUSE call
3067 WALKER for each virtual use that is equivalent to VUSE, including VUSE
3068 itself. That is, for each virtual use for which its defining statement
3069 does not clobber REF.
3071 WALKER is called with REF, the current virtual use and DATA. If
3072 WALKER returns non-NULL the walk stops and its result is returned.
3073 At the end of a non-successful walk NULL is returned.
3075 TRANSLATE if non-NULL is called with a pointer to REF, the virtual
3076 use which definition is a statement that may clobber REF and DATA.
3077 If TRANSLATE returns (void *)-1 the walk stops and NULL is returned.
3078 If TRANSLATE returns non-NULL the walk stops and its result is returned.
3079 If TRANSLATE returns NULL the walk continues and TRANSLATE is supposed
3080 to adjust REF and *DATA to make that valid.
3082 VALUEIZE if non-NULL is called with the next VUSE that is considered
3083 and return value is substituted for that. This can be used to
3084 implement optimistic value-numbering for example. Note that the
3085 VUSE argument is assumed to be valueized already.
3087 LIMIT specifies the number of alias queries we are allowed to do,
3088 the walk stops when it reaches zero and NULL is returned. LIMIT
3089 is decremented by the number of alias queries (plus adjustments
3090 done by the callbacks) upon return.
3092 TODO: Cache the vector of equivalent vuses per ref, vuse pair. */
3095 walk_non_aliased_vuses (ao_ref
*ref
, tree vuse
,
3096 void *(*walker
)(ao_ref
*, tree
, void *),
3097 void *(*translate
)(ao_ref
*, tree
, void *, bool *),
3098 tree (*valueize
)(tree
),
3099 unsigned &limit
, void *data
)
3101 bitmap visited
= NULL
;
3103 bool translated
= false;
3105 timevar_push (TV_ALIAS_STMT_WALK
);
3111 /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */
3112 res
= (*walker
) (ref
, vuse
, data
);
3114 if (res
== (void *)-1)
3119 /* Lookup succeeded. */
3120 else if (res
!= NULL
)
3125 vuse
= valueize (vuse
);
3132 def_stmt
= SSA_NAME_DEF_STMT (vuse
);
3133 if (gimple_nop_p (def_stmt
))
3135 else if (gimple_code (def_stmt
) == GIMPLE_PHI
)
3136 vuse
= get_continuation_for_phi (def_stmt
, ref
, limit
,
3137 &visited
, translated
, translate
, data
);
3140 if ((int)limit
<= 0)
3145 if (stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
3149 bool disambiguate_only
= false;
3150 res
= (*translate
) (ref
, vuse
, data
, &disambiguate_only
);
3151 /* Failed lookup and translation. */
3152 if (res
== (void *)-1)
3157 /* Lookup succeeded. */
3158 else if (res
!= NULL
)
3160 /* Translation succeeded, continue walking. */
3161 translated
= translated
|| !disambiguate_only
;
3163 vuse
= gimple_vuse (def_stmt
);
3169 BITMAP_FREE (visited
);
3171 timevar_pop (TV_ALIAS_STMT_WALK
);
3177 /* Based on the memory reference REF call WALKER for each vdef which
3178 defining statement may clobber REF, starting with VDEF. If REF
3179 is NULL_TREE, each defining statement is visited.
3181 WALKER is called with REF, the current vdef and DATA. If WALKER
3182 returns true the walk is stopped, otherwise it continues.
3184 If function entry is reached, FUNCTION_ENTRY_REACHED is set to true.
3185 The pointer may be NULL and then we do not track this information.
3187 At PHI nodes walk_aliased_vdefs forks into one walk for reach
3188 PHI argument (but only one walk continues on merge points), the
3189 return value is true if any of the walks was successful.
3191 The function returns the number of statements walked or -1 if
3192 LIMIT stmts were walked and the walk was aborted at this point.
3193 If LIMIT is zero the walk is not aborted. */
3196 walk_aliased_vdefs_1 (ao_ref
*ref
, tree vdef
,
3197 bool (*walker
)(ao_ref
*, tree
, void *), void *data
,
3198 bitmap
*visited
, unsigned int cnt
,
3199 bool *function_entry_reached
, unsigned limit
)
3203 gimple
*def_stmt
= SSA_NAME_DEF_STMT (vdef
);
3206 && !bitmap_set_bit (*visited
, SSA_NAME_VERSION (vdef
)))
3209 if (gimple_nop_p (def_stmt
))
3211 if (function_entry_reached
)
3212 *function_entry_reached
= true;
3215 else if (gimple_code (def_stmt
) == GIMPLE_PHI
)
3219 *visited
= BITMAP_ALLOC (NULL
);
3220 for (i
= 0; i
< gimple_phi_num_args (def_stmt
); ++i
)
3222 int res
= walk_aliased_vdefs_1 (ref
,
3223 gimple_phi_arg_def (def_stmt
, i
),
3224 walker
, data
, visited
, cnt
,
3225 function_entry_reached
, limit
);
3233 /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */
3238 || stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
3239 && (*walker
) (ref
, vdef
, data
))
3242 vdef
= gimple_vuse (def_stmt
);
3248 walk_aliased_vdefs (ao_ref
*ref
, tree vdef
,
3249 bool (*walker
)(ao_ref
*, tree
, void *), void *data
,
3251 bool *function_entry_reached
, unsigned int limit
)
3253 bitmap local_visited
= NULL
;
3256 timevar_push (TV_ALIAS_STMT_WALK
);
3258 if (function_entry_reached
)
3259 *function_entry_reached
= false;
3261 ret
= walk_aliased_vdefs_1 (ref
, vdef
, walker
, data
,
3262 visited
? visited
: &local_visited
, 0,
3263 function_entry_reached
, limit
);
3265 BITMAP_FREE (local_visited
);
3267 timevar_pop (TV_ALIAS_STMT_WALK
);