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
;
106 dump_alias_stats (FILE *s
)
108 fprintf (s
, "\nAlias oracle query stats:\n");
109 fprintf (s
, " refs_may_alias_p: "
110 HOST_WIDE_INT_PRINT_DEC
" disambiguations, "
111 HOST_WIDE_INT_PRINT_DEC
" queries\n",
112 alias_stats
.refs_may_alias_p_no_alias
,
113 alias_stats
.refs_may_alias_p_no_alias
114 + alias_stats
.refs_may_alias_p_may_alias
);
115 fprintf (s
, " ref_maybe_used_by_call_p: "
116 HOST_WIDE_INT_PRINT_DEC
" disambiguations, "
117 HOST_WIDE_INT_PRINT_DEC
" queries\n",
118 alias_stats
.ref_maybe_used_by_call_p_no_alias
,
119 alias_stats
.refs_may_alias_p_no_alias
120 + alias_stats
.ref_maybe_used_by_call_p_may_alias
);
121 fprintf (s
, " call_may_clobber_ref_p: "
122 HOST_WIDE_INT_PRINT_DEC
" disambiguations, "
123 HOST_WIDE_INT_PRINT_DEC
" queries\n",
124 alias_stats
.call_may_clobber_ref_p_no_alias
,
125 alias_stats
.call_may_clobber_ref_p_no_alias
126 + alias_stats
.call_may_clobber_ref_p_may_alias
);
127 fprintf (s
, " aliasing_component_ref_p: "
128 HOST_WIDE_INT_PRINT_DEC
" disambiguations, "
129 HOST_WIDE_INT_PRINT_DEC
" queries\n",
130 alias_stats
.aliasing_component_refs_p_no_alias
,
131 alias_stats
.aliasing_component_refs_p_no_alias
132 + alias_stats
.aliasing_component_refs_p_may_alias
);
133 dump_alias_stats_in_alias_c (s
);
137 /* Return true, if dereferencing PTR may alias with a global variable. */
140 ptr_deref_may_alias_global_p (tree ptr
)
142 struct ptr_info_def
*pi
;
144 /* If we end up with a pointer constant here that may point
146 if (TREE_CODE (ptr
) != SSA_NAME
)
149 pi
= SSA_NAME_PTR_INFO (ptr
);
151 /* If we do not have points-to information for this variable,
156 /* ??? This does not use TBAA to prune globals ptr may not access. */
157 return pt_solution_includes_global (&pi
->pt
);
160 /* Return true if dereferencing PTR may alias DECL.
161 The caller is responsible for applying TBAA to see if PTR
162 may access DECL at all. */
165 ptr_deref_may_alias_decl_p (tree ptr
, tree decl
)
167 struct ptr_info_def
*pi
;
169 /* Conversions are irrelevant for points-to information and
170 data-dependence analysis can feed us those. */
173 /* Anything we do not explicilty handle aliases. */
174 if ((TREE_CODE (ptr
) != SSA_NAME
175 && TREE_CODE (ptr
) != ADDR_EXPR
176 && TREE_CODE (ptr
) != POINTER_PLUS_EXPR
)
177 || !POINTER_TYPE_P (TREE_TYPE (ptr
))
179 && TREE_CODE (decl
) != PARM_DECL
180 && TREE_CODE (decl
) != RESULT_DECL
))
183 /* Disregard pointer offsetting. */
184 if (TREE_CODE (ptr
) == POINTER_PLUS_EXPR
)
188 ptr
= TREE_OPERAND (ptr
, 0);
190 while (TREE_CODE (ptr
) == POINTER_PLUS_EXPR
);
191 return ptr_deref_may_alias_decl_p (ptr
, decl
);
194 /* ADDR_EXPR pointers either just offset another pointer or directly
195 specify the pointed-to set. */
196 if (TREE_CODE (ptr
) == ADDR_EXPR
)
198 tree base
= get_base_address (TREE_OPERAND (ptr
, 0));
200 && (TREE_CODE (base
) == MEM_REF
201 || TREE_CODE (base
) == TARGET_MEM_REF
))
202 ptr
= TREE_OPERAND (base
, 0);
205 return compare_base_decls (base
, decl
) != 0;
207 && CONSTANT_CLASS_P (base
))
213 /* Non-aliased variables cannot be pointed to. */
214 if (!may_be_aliased (decl
))
217 /* If we do not have useful points-to information for this pointer
218 we cannot disambiguate anything else. */
219 pi
= SSA_NAME_PTR_INFO (ptr
);
223 return pt_solution_includes (&pi
->pt
, decl
);
226 /* Return true if dereferenced PTR1 and PTR2 may alias.
227 The caller is responsible for applying TBAA to see if accesses
228 through PTR1 and PTR2 may conflict at all. */
231 ptr_derefs_may_alias_p (tree ptr1
, tree ptr2
)
233 struct ptr_info_def
*pi1
, *pi2
;
235 /* Conversions are irrelevant for points-to information and
236 data-dependence analysis can feed us those. */
240 /* Disregard pointer offsetting. */
241 if (TREE_CODE (ptr1
) == POINTER_PLUS_EXPR
)
245 ptr1
= TREE_OPERAND (ptr1
, 0);
247 while (TREE_CODE (ptr1
) == POINTER_PLUS_EXPR
);
248 return ptr_derefs_may_alias_p (ptr1
, ptr2
);
250 if (TREE_CODE (ptr2
) == POINTER_PLUS_EXPR
)
254 ptr2
= TREE_OPERAND (ptr2
, 0);
256 while (TREE_CODE (ptr2
) == POINTER_PLUS_EXPR
);
257 return ptr_derefs_may_alias_p (ptr1
, ptr2
);
260 /* ADDR_EXPR pointers either just offset another pointer or directly
261 specify the pointed-to set. */
262 if (TREE_CODE (ptr1
) == ADDR_EXPR
)
264 tree base
= get_base_address (TREE_OPERAND (ptr1
, 0));
266 && (TREE_CODE (base
) == MEM_REF
267 || TREE_CODE (base
) == TARGET_MEM_REF
))
268 return ptr_derefs_may_alias_p (TREE_OPERAND (base
, 0), ptr2
);
271 return ptr_deref_may_alias_decl_p (ptr2
, base
);
275 if (TREE_CODE (ptr2
) == ADDR_EXPR
)
277 tree base
= get_base_address (TREE_OPERAND (ptr2
, 0));
279 && (TREE_CODE (base
) == MEM_REF
280 || TREE_CODE (base
) == TARGET_MEM_REF
))
281 return ptr_derefs_may_alias_p (ptr1
, TREE_OPERAND (base
, 0));
284 return ptr_deref_may_alias_decl_p (ptr1
, base
);
289 /* From here we require SSA name pointers. Anything else aliases. */
290 if (TREE_CODE (ptr1
) != SSA_NAME
291 || TREE_CODE (ptr2
) != SSA_NAME
292 || !POINTER_TYPE_P (TREE_TYPE (ptr1
))
293 || !POINTER_TYPE_P (TREE_TYPE (ptr2
)))
296 /* We may end up with two empty points-to solutions for two same pointers.
297 In this case we still want to say both pointers alias, so shortcut
302 /* If we do not have useful points-to information for either pointer
303 we cannot disambiguate anything else. */
304 pi1
= SSA_NAME_PTR_INFO (ptr1
);
305 pi2
= SSA_NAME_PTR_INFO (ptr2
);
309 /* ??? This does not use TBAA to prune decls from the intersection
310 that not both pointers may access. */
311 return pt_solutions_intersect (&pi1
->pt
, &pi2
->pt
);
314 /* Return true if dereferencing PTR may alias *REF.
315 The caller is responsible for applying TBAA to see if PTR
316 may access *REF at all. */
319 ptr_deref_may_alias_ref_p_1 (tree ptr
, ao_ref
*ref
)
321 tree base
= ao_ref_base (ref
);
323 if (TREE_CODE (base
) == MEM_REF
324 || TREE_CODE (base
) == TARGET_MEM_REF
)
325 return ptr_derefs_may_alias_p (ptr
, TREE_OPERAND (base
, 0));
326 else if (DECL_P (base
))
327 return ptr_deref_may_alias_decl_p (ptr
, base
);
332 /* Returns true if PTR1 and PTR2 compare unequal because of points-to. */
335 ptrs_compare_unequal (tree ptr1
, tree ptr2
)
337 /* First resolve the pointers down to a SSA name pointer base or
338 a VAR_DECL, PARM_DECL or RESULT_DECL. This explicitely does
339 not yet try to handle LABEL_DECLs, FUNCTION_DECLs, CONST_DECLs
340 or STRING_CSTs which needs points-to adjustments to track them
341 in the points-to sets. */
342 tree obj1
= NULL_TREE
;
343 tree obj2
= NULL_TREE
;
344 if (TREE_CODE (ptr1
) == ADDR_EXPR
)
346 tree tem
= get_base_address (TREE_OPERAND (ptr1
, 0));
350 || TREE_CODE (tem
) == PARM_DECL
351 || TREE_CODE (tem
) == RESULT_DECL
)
353 else if (TREE_CODE (tem
) == MEM_REF
)
354 ptr1
= TREE_OPERAND (tem
, 0);
356 if (TREE_CODE (ptr2
) == ADDR_EXPR
)
358 tree tem
= get_base_address (TREE_OPERAND (ptr2
, 0));
362 || TREE_CODE (tem
) == PARM_DECL
363 || TREE_CODE (tem
) == RESULT_DECL
)
365 else if (TREE_CODE (tem
) == MEM_REF
)
366 ptr2
= TREE_OPERAND (tem
, 0);
369 /* Canonicalize ptr vs. object. */
370 if (TREE_CODE (ptr1
) == SSA_NAME
&& obj2
)
372 std::swap (ptr1
, ptr2
);
373 std::swap (obj1
, obj2
);
377 /* Other code handles this correctly, no need to duplicate it here. */;
378 else if (obj1
&& TREE_CODE (ptr2
) == SSA_NAME
)
380 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (ptr2
);
381 /* We may not use restrict to optimize pointer comparisons.
382 See PR71062. So we have to assume that restrict-pointed-to
383 may be in fact obj1. */
385 || pi
->pt
.vars_contains_restrict
386 || pi
->pt
.vars_contains_interposable
)
389 && (TREE_STATIC (obj1
) || DECL_EXTERNAL (obj1
)))
391 varpool_node
*node
= varpool_node::get (obj1
);
392 /* If obj1 may bind to NULL give up (see below). */
394 || ! node
->nonzero_address ()
395 || ! decl_binds_to_current_def_p (obj1
))
398 return !pt_solution_includes (&pi
->pt
, obj1
);
401 /* ??? We'd like to handle ptr1 != NULL and ptr1 != ptr2
402 but those require pt.null to be conservatively correct. */
407 /* Returns whether reference REF to BASE may refer to global memory. */
410 ref_may_alias_global_p_1 (tree base
)
413 return is_global_var (base
);
414 else if (TREE_CODE (base
) == MEM_REF
415 || TREE_CODE (base
) == TARGET_MEM_REF
)
416 return ptr_deref_may_alias_global_p (TREE_OPERAND (base
, 0));
421 ref_may_alias_global_p (ao_ref
*ref
)
423 tree base
= ao_ref_base (ref
);
424 return ref_may_alias_global_p_1 (base
);
428 ref_may_alias_global_p (tree ref
)
430 tree base
= get_base_address (ref
);
431 return ref_may_alias_global_p_1 (base
);
434 /* Return true whether STMT may clobber global memory. */
437 stmt_may_clobber_global_p (gimple
*stmt
)
441 if (!gimple_vdef (stmt
))
444 /* ??? We can ask the oracle whether an artificial pointer
445 dereference with a pointer with points-to information covering
446 all global memory (what about non-address taken memory?) maybe
447 clobbered by this call. As there is at the moment no convenient
448 way of doing that without generating garbage do some manual
450 ??? We could make a NULL ao_ref argument to the various
451 predicates special, meaning any global memory. */
453 switch (gimple_code (stmt
))
456 lhs
= gimple_assign_lhs (stmt
);
457 return (TREE_CODE (lhs
) != SSA_NAME
458 && ref_may_alias_global_p (lhs
));
467 /* Dump alias information on FILE. */
470 dump_alias_info (FILE *file
)
475 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
478 fprintf (file
, "\n\nAlias information for %s\n\n", funcname
);
480 fprintf (file
, "Aliased symbols\n\n");
482 FOR_EACH_LOCAL_DECL (cfun
, i
, var
)
484 if (may_be_aliased (var
))
485 dump_variable (file
, var
);
488 fprintf (file
, "\nCall clobber information\n");
490 fprintf (file
, "\nESCAPED");
491 dump_points_to_solution (file
, &cfun
->gimple_df
->escaped
);
493 fprintf (file
, "\n\nFlow-insensitive points-to information\n\n");
495 FOR_EACH_SSA_NAME (i
, ptr
, cfun
)
497 struct ptr_info_def
*pi
;
499 if (!POINTER_TYPE_P (TREE_TYPE (ptr
))
500 || SSA_NAME_IN_FREE_LIST (ptr
))
503 pi
= SSA_NAME_PTR_INFO (ptr
);
505 dump_points_to_info_for (file
, ptr
);
508 fprintf (file
, "\n");
512 /* Dump alias information on stderr. */
515 debug_alias_info (void)
517 dump_alias_info (stderr
);
521 /* Dump the points-to set *PT into FILE. */
524 dump_points_to_solution (FILE *file
, struct pt_solution
*pt
)
527 fprintf (file
, ", points-to anything");
530 fprintf (file
, ", points-to non-local");
533 fprintf (file
, ", points-to escaped");
536 fprintf (file
, ", points-to unit escaped");
539 fprintf (file
, ", points-to NULL");
543 fprintf (file
, ", points-to vars: ");
544 dump_decl_set (file
, pt
->vars
);
545 if (pt
->vars_contains_nonlocal
546 || pt
->vars_contains_escaped
547 || pt
->vars_contains_escaped_heap
548 || pt
->vars_contains_restrict
)
550 const char *comma
= "";
551 fprintf (file
, " (");
552 if (pt
->vars_contains_nonlocal
)
554 fprintf (file
, "nonlocal");
557 if (pt
->vars_contains_escaped
)
559 fprintf (file
, "%sescaped", comma
);
562 if (pt
->vars_contains_escaped_heap
)
564 fprintf (file
, "%sescaped heap", comma
);
567 if (pt
->vars_contains_restrict
)
569 fprintf (file
, "%srestrict", comma
);
572 if (pt
->vars_contains_interposable
)
573 fprintf (file
, "%sinterposable", comma
);
580 /* Unified dump function for pt_solution. */
583 debug (pt_solution
&ref
)
585 dump_points_to_solution (stderr
, &ref
);
589 debug (pt_solution
*ptr
)
594 fprintf (stderr
, "<nil>\n");
598 /* Dump points-to information for SSA_NAME PTR into FILE. */
601 dump_points_to_info_for (FILE *file
, tree ptr
)
603 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (ptr
);
605 print_generic_expr (file
, ptr
, dump_flags
);
608 dump_points_to_solution (file
, &pi
->pt
);
610 fprintf (file
, ", points-to anything");
612 fprintf (file
, "\n");
616 /* Dump points-to information for VAR into stderr. */
619 debug_points_to_info_for (tree var
)
621 dump_points_to_info_for (stderr
, var
);
625 /* Initializes the alias-oracle reference representation *R from REF. */
628 ao_ref_init (ao_ref
*r
, tree ref
)
635 r
->ref_alias_set
= -1;
636 r
->base_alias_set
= -1;
637 r
->volatile_p
= ref
? TREE_THIS_VOLATILE (ref
) : false;
640 /* Returns the base object of the memory reference *REF. */
643 ao_ref_base (ao_ref
*ref
)
649 ref
->base
= get_ref_base_and_extent (ref
->ref
, &ref
->offset
, &ref
->size
,
650 &ref
->max_size
, &reverse
);
654 /* Returns the base object alias set of the memory reference *REF. */
657 ao_ref_base_alias_set (ao_ref
*ref
)
660 if (ref
->base_alias_set
!= -1)
661 return ref
->base_alias_set
;
665 while (handled_component_p (base_ref
))
666 base_ref
= TREE_OPERAND (base_ref
, 0);
667 ref
->base_alias_set
= get_alias_set (base_ref
);
668 return ref
->base_alias_set
;
671 /* Returns the reference alias set of the memory reference *REF. */
674 ao_ref_alias_set (ao_ref
*ref
)
676 if (ref
->ref_alias_set
!= -1)
677 return ref
->ref_alias_set
;
678 ref
->ref_alias_set
= get_alias_set (ref
->ref
);
679 return ref
->ref_alias_set
;
682 /* Init an alias-oracle reference representation from a gimple pointer
683 PTR and a gimple size SIZE in bytes. If SIZE is NULL_TREE then the
684 size is assumed to be unknown. The access is assumed to be only
685 to or after of the pointer target, not before it. */
688 ao_ref_init_from_ptr_and_size (ao_ref
*ref
, tree ptr
, tree size
)
690 poly_int64 t
, size_hwi
, extra_offset
= 0;
691 ref
->ref
= NULL_TREE
;
692 if (TREE_CODE (ptr
) == SSA_NAME
)
694 gimple
*stmt
= SSA_NAME_DEF_STMT (ptr
);
695 if (gimple_assign_single_p (stmt
)
696 && gimple_assign_rhs_code (stmt
) == ADDR_EXPR
)
697 ptr
= gimple_assign_rhs1 (stmt
);
698 else if (is_gimple_assign (stmt
)
699 && gimple_assign_rhs_code (stmt
) == POINTER_PLUS_EXPR
700 && ptrdiff_tree_p (gimple_assign_rhs2 (stmt
), &extra_offset
))
702 ptr
= gimple_assign_rhs1 (stmt
);
703 extra_offset
*= BITS_PER_UNIT
;
707 if (TREE_CODE (ptr
) == ADDR_EXPR
)
709 ref
->base
= get_addr_base_and_unit_offset (TREE_OPERAND (ptr
, 0), &t
);
711 ref
->offset
= BITS_PER_UNIT
* t
;
716 ref
->base
= get_base_address (TREE_OPERAND (ptr
, 0));
721 gcc_assert (POINTER_TYPE_P (TREE_TYPE (ptr
)));
722 ref
->base
= build2 (MEM_REF
, char_type_node
,
723 ptr
, null_pointer_node
);
726 ref
->offset
+= extra_offset
;
728 && poly_int_tree_p (size
, &size_hwi
)
729 && coeffs_in_range_p (size_hwi
, 0, HOST_WIDE_INT_MAX
/ BITS_PER_UNIT
))
730 ref
->max_size
= ref
->size
= size_hwi
* BITS_PER_UNIT
;
732 ref
->max_size
= ref
->size
= -1;
733 ref
->ref_alias_set
= 0;
734 ref
->base_alias_set
= 0;
735 ref
->volatile_p
= false;
738 /* S1 and S2 are TYPE_SIZE or DECL_SIZE. Compare them:
741 Return 0 if equal or incomparable. */
744 compare_sizes (tree s1
, tree s2
)
752 if (!poly_int_tree_p (s1
, &size1
) || !poly_int_tree_p (s2
, &size2
))
754 if (known_lt (size1
, size2
))
756 if (known_lt (size2
, size1
))
761 /* Compare TYPE1 and TYPE2 by its size.
762 Return -1 if size of TYPE1 < size of TYPE2
763 Return 1 if size of TYPE1 > size of TYPE2
764 Return 0 if types are of equal sizes or we can not compare them. */
767 compare_type_sizes (tree type1
, tree type2
)
769 /* Be conservative for arrays and vectors. We want to support partial
770 overlap on int[3] and int[3] as tested in gcc.dg/torture/alias-2.c. */
771 while (TREE_CODE (type1
) == ARRAY_TYPE
772 || TREE_CODE (type1
) == VECTOR_TYPE
)
773 type1
= TREE_TYPE (type1
);
774 while (TREE_CODE (type2
) == ARRAY_TYPE
775 || TREE_CODE (type2
) == VECTOR_TYPE
)
776 type2
= TREE_TYPE (type2
);
777 return compare_sizes (TYPE_SIZE (type1
), TYPE_SIZE (type2
));
780 /* Return 1 if TYPE1 and TYPE2 are to be considered equivalent for the
781 purpose of TBAA. Return 0 if they are distinct and -1 if we cannot
785 same_type_for_tbaa (tree type1
, tree type2
)
787 type1
= TYPE_MAIN_VARIANT (type1
);
788 type2
= TYPE_MAIN_VARIANT (type2
);
790 /* Handle the most common case first. */
794 /* If we would have to do structural comparison bail out. */
795 if (TYPE_STRUCTURAL_EQUALITY_P (type1
)
796 || TYPE_STRUCTURAL_EQUALITY_P (type2
))
799 /* Compare the canonical types. */
800 if (TYPE_CANONICAL (type1
) == TYPE_CANONICAL (type2
))
803 /* ??? Array types are not properly unified in all cases as we have
804 spurious changes in the index types for example. Removing this
805 causes all sorts of problems with the Fortran frontend. */
806 if (TREE_CODE (type1
) == ARRAY_TYPE
807 && TREE_CODE (type2
) == ARRAY_TYPE
)
810 /* ??? In Ada, an lvalue of an unconstrained type can be used to access an
811 object of one of its constrained subtypes, e.g. when a function with an
812 unconstrained parameter passed by reference is called on an object and
813 inlined. But, even in the case of a fixed size, type and subtypes are
814 not equivalent enough as to share the same TYPE_CANONICAL, since this
815 would mean that conversions between them are useless, whereas they are
816 not (e.g. type and subtypes can have different modes). So, in the end,
817 they are only guaranteed to have the same alias set. */
818 if (get_alias_set (type1
) == get_alias_set (type2
))
821 /* The types are known to be not equal. */
825 /* Return true if TYPE is a composite type (i.e. we may apply one of handled
826 components on it). */
829 type_has_components_p (tree type
)
831 return AGGREGATE_TYPE_P (type
) || VECTOR_TYPE_P (type
)
832 || TREE_CODE (type
) == COMPLEX_TYPE
;
835 /* Determine if the two component references REF1 and REF2 which are
836 based on access types TYPE1 and TYPE2 and of which at least one is based
837 on an indirect reference may alias. REF2 is the only one that can
838 be a decl in which case REF2_IS_DECL is true.
839 REF1_ALIAS_SET, BASE1_ALIAS_SET, REF2_ALIAS_SET and BASE2_ALIAS_SET
840 are the respective alias sets. */
843 aliasing_component_refs_p (tree ref1
,
844 alias_set_type ref1_alias_set
,
845 alias_set_type base1_alias_set
,
846 poly_int64 offset1
, poly_int64 max_size1
,
848 alias_set_type ref2_alias_set
,
849 alias_set_type base2_alias_set
,
850 poly_int64 offset2
, poly_int64 max_size2
,
853 /* If one reference is a component references through pointers try to find a
854 common base and apply offset based disambiguation. This handles
856 struct A { int i; int j; } *q;
857 struct B { struct A a; int k; } *p;
858 disambiguating q->i and p->a.j. */
862 int same_p1
= 0, same_p2
= 0;
863 bool maybe_match
= false;
865 /* Choose bases and base types to search for. */
867 while (handled_component_p (base1
))
868 base1
= TREE_OPERAND (base1
, 0);
869 type1
= TREE_TYPE (base1
);
871 while (handled_component_p (base2
))
872 base2
= TREE_OPERAND (base2
, 0);
873 type2
= TREE_TYPE (base2
);
875 /* Now search for the type1 in the access path of ref2. This
876 would be a common base for doing offset based disambiguation on.
877 This however only makes sense if type2 is big enough to hold type1. */
878 int cmp_outer
= compare_type_sizes (type2
, type1
);
884 /* We walk from inner type to the outer types. If type we see is
885 already too large to be part of type1, terminate the search. */
886 int cmp
= compare_type_sizes (type1
, TREE_TYPE (*refp
));
889 /* If types may be of same size, see if we can decide about their
893 same_p2
= same_type_for_tbaa (TREE_TYPE (*refp
), type1
);
896 /* In case we can't decide whether types are same try to
897 continue looking for the exact match.
898 Remember however that we possibly saw a match
899 to bypass the access path continuations tests we do later. */
903 if (!handled_component_p (*refp
))
905 refp
= &TREE_OPERAND (*refp
, 0);
909 poly_int64 offadj
, sztmp
, msztmp
;
912 /* We assume that arrays can overlap by multiple of their elements
913 size as tested in gcc.dg/torture/alias-2.c.
914 This partial overlap happen only when both arrays are bases of
915 the access and not contained within another component ref.
916 To be safe we also assume partial overlap for VLAs. */
917 if (TREE_CODE (TREE_TYPE (base1
)) == ARRAY_TYPE
918 && (!TYPE_SIZE (TREE_TYPE (base1
))
919 || TREE_CODE (TYPE_SIZE (TREE_TYPE (base1
))) != INTEGER_CST
920 || (*refp
== base2
&& !ref2_is_decl
)))
922 ++alias_stats
.aliasing_component_refs_p_may_alias
;
926 get_ref_base_and_extent (*refp
, &offadj
, &sztmp
, &msztmp
, &reverse
);
928 get_ref_base_and_extent (base1
, &offadj
, &sztmp
, &msztmp
, &reverse
);
930 if (ranges_maybe_overlap_p (offset1
, max_size1
, offset2
, max_size2
))
932 ++alias_stats
.aliasing_component_refs_p_may_alias
;
937 ++alias_stats
.aliasing_component_refs_p_no_alias
;
943 /* If we didn't find a common base, try the other way around. */
949 int cmp
= compare_type_sizes (type2
, TREE_TYPE (*refp
));
952 /* If types may be of same size, see if we can decide about their
956 same_p1
= same_type_for_tbaa (TREE_TYPE (*refp
), type2
);
962 if (!handled_component_p (*refp
))
964 refp
= &TREE_OPERAND (*refp
, 0);
968 poly_int64 offadj
, sztmp
, msztmp
;
971 if (TREE_CODE (TREE_TYPE (base2
)) == ARRAY_TYPE
972 && (!TYPE_SIZE (TREE_TYPE (base2
))
973 || TREE_CODE (TYPE_SIZE (TREE_TYPE (base2
))) != INTEGER_CST
974 || (*refp
== base1
&& !ref2_is_decl
)))
976 ++alias_stats
.aliasing_component_refs_p_may_alias
;
980 get_ref_base_and_extent (*refp
, &offadj
, &sztmp
, &msztmp
, &reverse
);
982 get_ref_base_and_extent (base2
, &offadj
, &sztmp
, &msztmp
, &reverse
);
984 if (ranges_maybe_overlap_p (offset1
, max_size1
, offset2
, max_size2
))
986 ++alias_stats
.aliasing_component_refs_p_may_alias
;
991 ++alias_stats
.aliasing_component_refs_p_no_alias
;
997 /* In the following code we make an assumption that the types in access
998 paths do not overlap and thus accesses alias only if one path can be
999 continuation of another. If we was not able to decide about equivalence,
1000 we need to give up. */
1004 /* If we have two type access paths B1.path1 and B2.path2 they may
1005 only alias if either B1 is in B2.path2 or B2 is in B1.path1.
1006 But we can still have a path that goes B1.path1...B2.path2 with
1007 a part that we do not see. So we can only disambiguate now
1008 if there is no B2 in the tail of path1 and no B1 on the
1010 if (compare_type_sizes (TREE_TYPE (ref2
), type1
) >= 0
1011 && type_has_components_p (TREE_TYPE (ref2
))
1012 && (base1_alias_set
== ref2_alias_set
1013 || alias_set_subset_of (base1_alias_set
, ref2_alias_set
)))
1015 ++alias_stats
.aliasing_component_refs_p_may_alias
;
1018 /* If this is ptr vs. decl then we know there is no ptr ... decl path. */
1020 && compare_type_sizes (TREE_TYPE (ref1
), type2
) >= 0
1021 && type_has_components_p (TREE_TYPE (ref1
))
1022 && (base2_alias_set
== ref1_alias_set
1023 || alias_set_subset_of (base2_alias_set
, ref1_alias_set
)))
1025 ++alias_stats
.aliasing_component_refs_p_may_alias
;
1028 ++alias_stats
.aliasing_component_refs_p_no_alias
;
1032 /* Return true if we can determine that component references REF1 and REF2,
1033 that are within a common DECL, cannot overlap. */
1036 nonoverlapping_component_refs_of_decl_p (tree ref1
, tree ref2
)
1038 auto_vec
<tree
, 16> component_refs1
;
1039 auto_vec
<tree
, 16> component_refs2
;
1041 /* Create the stack of handled components for REF1. */
1042 while (handled_component_p (ref1
))
1044 component_refs1
.safe_push (ref1
);
1045 ref1
= TREE_OPERAND (ref1
, 0);
1047 if (TREE_CODE (ref1
) == MEM_REF
)
1049 if (!integer_zerop (TREE_OPERAND (ref1
, 1)))
1051 ref1
= TREE_OPERAND (TREE_OPERAND (ref1
, 0), 0);
1054 /* Create the stack of handled components for REF2. */
1055 while (handled_component_p (ref2
))
1057 component_refs2
.safe_push (ref2
);
1058 ref2
= TREE_OPERAND (ref2
, 0);
1060 if (TREE_CODE (ref2
) == MEM_REF
)
1062 if (!integer_zerop (TREE_OPERAND (ref2
, 1)))
1064 ref2
= TREE_OPERAND (TREE_OPERAND (ref2
, 0), 0);
1067 /* Bases must be either same or uncomparable. */
1068 gcc_checking_assert (ref1
== ref2
1069 || (DECL_P (ref1
) && DECL_P (ref2
)
1070 && compare_base_decls (ref1
, ref2
) != 0));
1072 /* Pop the stacks in parallel and examine the COMPONENT_REFs of the same
1073 rank. This is sufficient because we start from the same DECL and you
1074 cannot reference several fields at a time with COMPONENT_REFs (unlike
1075 with ARRAY_RANGE_REFs for arrays) so you always need the same number
1076 of them to access a sub-component, unless you're in a union, in which
1077 case the return value will precisely be false. */
1082 if (component_refs1
.is_empty ())
1084 ref1
= component_refs1
.pop ();
1086 while (!RECORD_OR_UNION_TYPE_P (TREE_TYPE (TREE_OPERAND (ref1
, 0))));
1090 if (component_refs2
.is_empty ())
1092 ref2
= component_refs2
.pop ();
1094 while (!RECORD_OR_UNION_TYPE_P (TREE_TYPE (TREE_OPERAND (ref2
, 0))));
1096 /* Beware of BIT_FIELD_REF. */
1097 if (TREE_CODE (ref1
) != COMPONENT_REF
1098 || TREE_CODE (ref2
) != COMPONENT_REF
)
1101 tree field1
= TREE_OPERAND (ref1
, 1);
1102 tree field2
= TREE_OPERAND (ref2
, 1);
1104 /* ??? We cannot simply use the type of operand #0 of the refs here
1105 as the Fortran compiler smuggles type punning into COMPONENT_REFs
1106 for common blocks instead of using unions like everyone else. */
1107 tree type1
= DECL_CONTEXT (field1
);
1108 tree type2
= DECL_CONTEXT (field2
);
1110 /* We cannot disambiguate fields in a union or qualified union. */
1111 if (type1
!= type2
|| TREE_CODE (type1
) != RECORD_TYPE
)
1114 if (field1
!= field2
)
1116 /* A field and its representative need to be considered the
1118 if (DECL_BIT_FIELD_REPRESENTATIVE (field1
) == field2
1119 || DECL_BIT_FIELD_REPRESENTATIVE (field2
) == field1
)
1121 /* Different fields of the same record type cannot overlap.
1122 ??? Bitfields can overlap at RTL level so punt on them. */
1123 if (DECL_BIT_FIELD (field1
) && DECL_BIT_FIELD (field2
))
1132 /* qsort compare function to sort FIELD_DECLs after their
1133 DECL_FIELD_CONTEXT TYPE_UID. */
1136 ncr_compar (const void *field1_
, const void *field2_
)
1138 const_tree field1
= *(const_tree
*) const_cast <void *>(field1_
);
1139 const_tree field2
= *(const_tree
*) const_cast <void *>(field2_
);
1140 unsigned int uid1
= TYPE_UID (DECL_FIELD_CONTEXT (field1
));
1141 unsigned int uid2
= TYPE_UID (DECL_FIELD_CONTEXT (field2
));
1144 else if (uid1
> uid2
)
1149 /* Return true if we can determine that the fields referenced cannot
1150 overlap for any pair of objects. */
1153 nonoverlapping_component_refs_p (const_tree x
, const_tree y
)
1155 if (!flag_strict_aliasing
1157 || TREE_CODE (x
) != COMPONENT_REF
1158 || TREE_CODE (y
) != COMPONENT_REF
)
1161 auto_vec
<const_tree
, 16> fieldsx
;
1162 while (TREE_CODE (x
) == COMPONENT_REF
)
1164 tree field
= TREE_OPERAND (x
, 1);
1165 tree type
= DECL_FIELD_CONTEXT (field
);
1166 if (TREE_CODE (type
) == RECORD_TYPE
)
1167 fieldsx
.safe_push (field
);
1168 x
= TREE_OPERAND (x
, 0);
1170 if (fieldsx
.length () == 0)
1172 auto_vec
<const_tree
, 16> fieldsy
;
1173 while (TREE_CODE (y
) == COMPONENT_REF
)
1175 tree field
= TREE_OPERAND (y
, 1);
1176 tree type
= DECL_FIELD_CONTEXT (field
);
1177 if (TREE_CODE (type
) == RECORD_TYPE
)
1178 fieldsy
.safe_push (TREE_OPERAND (y
, 1));
1179 y
= TREE_OPERAND (y
, 0);
1181 if (fieldsy
.length () == 0)
1184 /* Most common case first. */
1185 if (fieldsx
.length () == 1
1186 && fieldsy
.length () == 1)
1187 return ((DECL_FIELD_CONTEXT (fieldsx
[0])
1188 == DECL_FIELD_CONTEXT (fieldsy
[0]))
1189 && fieldsx
[0] != fieldsy
[0]
1190 && !(DECL_BIT_FIELD (fieldsx
[0]) && DECL_BIT_FIELD (fieldsy
[0])));
1192 if (fieldsx
.length () == 2)
1194 if (ncr_compar (&fieldsx
[0], &fieldsx
[1]) == 1)
1195 std::swap (fieldsx
[0], fieldsx
[1]);
1198 fieldsx
.qsort (ncr_compar
);
1200 if (fieldsy
.length () == 2)
1202 if (ncr_compar (&fieldsy
[0], &fieldsy
[1]) == 1)
1203 std::swap (fieldsy
[0], fieldsy
[1]);
1206 fieldsy
.qsort (ncr_compar
);
1208 unsigned i
= 0, j
= 0;
1211 const_tree fieldx
= fieldsx
[i
];
1212 const_tree fieldy
= fieldsy
[j
];
1213 tree typex
= DECL_FIELD_CONTEXT (fieldx
);
1214 tree typey
= DECL_FIELD_CONTEXT (fieldy
);
1217 /* We're left with accessing different fields of a structure,
1218 no possible overlap. */
1219 if (fieldx
!= fieldy
)
1221 /* A field and its representative need to be considered the
1223 if (DECL_BIT_FIELD_REPRESENTATIVE (fieldx
) == fieldy
1224 || DECL_BIT_FIELD_REPRESENTATIVE (fieldy
) == fieldx
)
1226 /* Different fields of the same record type cannot overlap.
1227 ??? Bitfields can overlap at RTL level so punt on them. */
1228 if (DECL_BIT_FIELD (fieldx
) && DECL_BIT_FIELD (fieldy
))
1233 if (TYPE_UID (typex
) < TYPE_UID (typey
))
1236 if (i
== fieldsx
.length ())
1242 if (j
== fieldsy
.length ())
1252 /* Return true if two memory references based on the variables BASE1
1253 and BASE2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and
1254 [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. REF1 and REF2
1255 if non-NULL are the complete memory reference trees. */
1258 decl_refs_may_alias_p (tree ref1
, tree base1
,
1259 poly_int64 offset1
, poly_int64 max_size1
,
1260 tree ref2
, tree base2
,
1261 poly_int64 offset2
, poly_int64 max_size2
)
1263 gcc_checking_assert (DECL_P (base1
) && DECL_P (base2
));
1265 /* If both references are based on different variables, they cannot alias. */
1266 if (compare_base_decls (base1
, base2
) == 0)
1269 /* If both references are based on the same variable, they cannot alias if
1270 the accesses do not overlap. */
1271 if (!ranges_maybe_overlap_p (offset1
, max_size1
, offset2
, max_size2
))
1274 /* For components with variable position, the above test isn't sufficient,
1275 so we disambiguate component references manually. */
1277 && handled_component_p (ref1
) && handled_component_p (ref2
)
1278 && nonoverlapping_component_refs_of_decl_p (ref1
, ref2
))
1284 /* Return true if an indirect reference based on *PTR1 constrained
1285 to [OFFSET1, OFFSET1 + MAX_SIZE1) may alias a variable based on BASE2
1286 constrained to [OFFSET2, OFFSET2 + MAX_SIZE2). *PTR1 and BASE2 have
1287 the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1
1288 in which case they are computed on-demand. REF1 and REF2
1289 if non-NULL are the complete memory reference trees. */
1292 indirect_ref_may_alias_decl_p (tree ref1 ATTRIBUTE_UNUSED
, tree base1
,
1293 poly_int64 offset1
, poly_int64 max_size1
,
1294 alias_set_type ref1_alias_set
,
1295 alias_set_type base1_alias_set
,
1296 tree ref2 ATTRIBUTE_UNUSED
, tree base2
,
1297 poly_int64 offset2
, poly_int64 max_size2
,
1298 alias_set_type ref2_alias_set
,
1299 alias_set_type base2_alias_set
, bool tbaa_p
)
1302 tree ptrtype1
, dbase2
;
1304 gcc_checking_assert ((TREE_CODE (base1
) == MEM_REF
1305 || TREE_CODE (base1
) == TARGET_MEM_REF
)
1308 ptr1
= TREE_OPERAND (base1
, 0);
1309 poly_offset_int moff
= mem_ref_offset (base1
) << LOG2_BITS_PER_UNIT
;
1311 /* If only one reference is based on a variable, they cannot alias if
1312 the pointer access is beyond the extent of the variable access.
1313 (the pointer base cannot validly point to an offset less than zero
1315 ??? IVOPTs creates bases that do not honor this restriction,
1316 so do not apply this optimization for TARGET_MEM_REFs. */
1317 if (TREE_CODE (base1
) != TARGET_MEM_REF
1318 && !ranges_maybe_overlap_p (offset1
+ moff
, -1, offset2
, max_size2
))
1320 /* They also cannot alias if the pointer may not point to the decl. */
1321 if (!ptr_deref_may_alias_decl_p (ptr1
, base2
))
1324 /* Disambiguations that rely on strict aliasing rules follow. */
1325 if (!flag_strict_aliasing
|| !tbaa_p
)
1328 ptrtype1
= TREE_TYPE (TREE_OPERAND (base1
, 1));
1330 /* If the alias set for a pointer access is zero all bets are off. */
1331 if (base1_alias_set
== 0)
1334 /* When we are trying to disambiguate an access with a pointer dereference
1335 as base versus one with a decl as base we can use both the size
1336 of the decl and its dynamic type for extra disambiguation.
1337 ??? We do not know anything about the dynamic type of the decl
1338 other than that its alias-set contains base2_alias_set as a subset
1339 which does not help us here. */
1340 /* As we know nothing useful about the dynamic type of the decl just
1341 use the usual conflict check rather than a subset test.
1342 ??? We could introduce -fvery-strict-aliasing when the language
1343 does not allow decls to have a dynamic type that differs from their
1344 static type. Then we can check
1345 !alias_set_subset_of (base1_alias_set, base2_alias_set) instead. */
1346 if (base1_alias_set
!= base2_alias_set
1347 && !alias_sets_conflict_p (base1_alias_set
, base2_alias_set
))
1349 /* If the size of the access relevant for TBAA through the pointer
1350 is bigger than the size of the decl we can't possibly access the
1351 decl via that pointer. */
1352 if (/* ??? This in turn may run afoul when a decl of type T which is
1353 a member of union type U is accessed through a pointer to
1354 type U and sizeof T is smaller than sizeof U. */
1355 TREE_CODE (TREE_TYPE (ptrtype1
)) != UNION_TYPE
1356 && TREE_CODE (TREE_TYPE (ptrtype1
)) != QUAL_UNION_TYPE
1357 && compare_sizes (DECL_SIZE (base2
),
1358 TYPE_SIZE (TREE_TYPE (ptrtype1
))) < 0)
1364 /* If the decl is accessed via a MEM_REF, reconstruct the base
1365 we can use for TBAA and an appropriately adjusted offset. */
1367 while (handled_component_p (dbase2
))
1368 dbase2
= TREE_OPERAND (dbase2
, 0);
1369 poly_int64 doffset1
= offset1
;
1370 poly_offset_int doffset2
= offset2
;
1371 if (TREE_CODE (dbase2
) == MEM_REF
1372 || TREE_CODE (dbase2
) == TARGET_MEM_REF
)
1374 doffset2
-= mem_ref_offset (dbase2
) << LOG2_BITS_PER_UNIT
;
1375 tree ptrtype2
= TREE_TYPE (TREE_OPERAND (dbase2
, 1));
1376 /* If second reference is view-converted, give up now. */
1377 if (same_type_for_tbaa (TREE_TYPE (dbase2
), TREE_TYPE (ptrtype2
)) != 1)
1381 /* If first reference is view-converted, give up now. */
1382 if (same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (ptrtype1
)) != 1)
1385 /* If both references are through the same type, they do not alias
1386 if the accesses do not overlap. This does extra disambiguation
1387 for mixed/pointer accesses but requires strict aliasing.
1388 For MEM_REFs we require that the component-ref offset we computed
1389 is relative to the start of the type which we ensure by
1390 comparing rvalue and access type and disregarding the constant
1393 But avoid treating variable length arrays as "objects", instead assume they
1394 can overlap by an exact multiple of their element size.
1395 See gcc.dg/torture/alias-2.c. */
1396 if (((TREE_CODE (base1
) != TARGET_MEM_REF
1397 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1398 && (TREE_CODE (dbase2
) != TARGET_MEM_REF
1399 || (!TMR_INDEX (dbase2
) && !TMR_INDEX2 (base2
))))
1400 && same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (dbase2
)) == 1
1401 && (TREE_CODE (TREE_TYPE (base1
)) != ARRAY_TYPE
1402 || (TYPE_SIZE (TREE_TYPE (base1
))
1403 && TREE_CODE (TYPE_SIZE (TREE_TYPE (base1
))) == INTEGER_CST
)))
1404 return ranges_maybe_overlap_p (doffset1
, max_size1
, doffset2
, max_size2
);
1407 && nonoverlapping_component_refs_p (ref1
, ref2
))
1410 /* Do access-path based disambiguation. */
1412 && (handled_component_p (ref1
) || handled_component_p (ref2
)))
1413 return aliasing_component_refs_p (ref1
,
1414 ref1_alias_set
, base1_alias_set
,
1417 ref2_alias_set
, base2_alias_set
,
1419 /* Only if the other reference is actual
1420 decl we can safely check only toplevel
1421 part of access path 1. */
1422 same_type_for_tbaa (TREE_TYPE (dbase2
),
1429 /* Return true if two indirect references based on *PTR1
1430 and *PTR2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and
1431 [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. *PTR1 and *PTR2 have
1432 the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1
1433 in which case they are computed on-demand. REF1 and REF2
1434 if non-NULL are the complete memory reference trees. */
1437 indirect_refs_may_alias_p (tree ref1 ATTRIBUTE_UNUSED
, tree base1
,
1438 poly_int64 offset1
, poly_int64 max_size1
,
1439 alias_set_type ref1_alias_set
,
1440 alias_set_type base1_alias_set
,
1441 tree ref2 ATTRIBUTE_UNUSED
, tree base2
,
1442 poly_int64 offset2
, poly_int64 max_size2
,
1443 alias_set_type ref2_alias_set
,
1444 alias_set_type base2_alias_set
, bool tbaa_p
)
1448 tree ptrtype1
, ptrtype2
;
1450 gcc_checking_assert ((TREE_CODE (base1
) == MEM_REF
1451 || TREE_CODE (base1
) == TARGET_MEM_REF
)
1452 && (TREE_CODE (base2
) == MEM_REF
1453 || TREE_CODE (base2
) == TARGET_MEM_REF
));
1455 ptr1
= TREE_OPERAND (base1
, 0);
1456 ptr2
= TREE_OPERAND (base2
, 0);
1458 /* If both bases are based on pointers they cannot alias if they may not
1459 point to the same memory object or if they point to the same object
1460 and the accesses do not overlap. */
1461 if ((!cfun
|| gimple_in_ssa_p (cfun
))
1462 && operand_equal_p (ptr1
, ptr2
, 0)
1463 && (((TREE_CODE (base1
) != TARGET_MEM_REF
1464 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1465 && (TREE_CODE (base2
) != TARGET_MEM_REF
1466 || (!TMR_INDEX (base2
) && !TMR_INDEX2 (base2
))))
1467 || (TREE_CODE (base1
) == TARGET_MEM_REF
1468 && TREE_CODE (base2
) == TARGET_MEM_REF
1469 && (TMR_STEP (base1
) == TMR_STEP (base2
)
1470 || (TMR_STEP (base1
) && TMR_STEP (base2
)
1471 && operand_equal_p (TMR_STEP (base1
),
1472 TMR_STEP (base2
), 0)))
1473 && (TMR_INDEX (base1
) == TMR_INDEX (base2
)
1474 || (TMR_INDEX (base1
) && TMR_INDEX (base2
)
1475 && operand_equal_p (TMR_INDEX (base1
),
1476 TMR_INDEX (base2
), 0)))
1477 && (TMR_INDEX2 (base1
) == TMR_INDEX2 (base2
)
1478 || (TMR_INDEX2 (base1
) && TMR_INDEX2 (base2
)
1479 && operand_equal_p (TMR_INDEX2 (base1
),
1480 TMR_INDEX2 (base2
), 0))))))
1482 poly_offset_int moff1
= mem_ref_offset (base1
) << LOG2_BITS_PER_UNIT
;
1483 poly_offset_int moff2
= mem_ref_offset (base2
) << LOG2_BITS_PER_UNIT
;
1484 return ranges_maybe_overlap_p (offset1
+ moff1
, max_size1
,
1485 offset2
+ moff2
, max_size2
);
1487 if (!ptr_derefs_may_alias_p (ptr1
, ptr2
))
1490 /* Disambiguations that rely on strict aliasing rules follow. */
1491 if (!flag_strict_aliasing
|| !tbaa_p
)
1494 ptrtype1
= TREE_TYPE (TREE_OPERAND (base1
, 1));
1495 ptrtype2
= TREE_TYPE (TREE_OPERAND (base2
, 1));
1497 /* If the alias set for a pointer access is zero all bets are off. */
1498 if (base1_alias_set
== 0
1499 || base2_alias_set
== 0)
1502 /* Do type-based disambiguation. */
1503 if (base1_alias_set
!= base2_alias_set
1504 && !alias_sets_conflict_p (base1_alias_set
, base2_alias_set
))
1507 /* If either reference is view-converted, give up now. */
1508 if (same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (ptrtype1
)) != 1
1509 || same_type_for_tbaa (TREE_TYPE (base2
), TREE_TYPE (ptrtype2
)) != 1)
1512 /* If both references are through the same type, they do not alias
1513 if the accesses do not overlap. This does extra disambiguation
1514 for mixed/pointer accesses but requires strict aliasing. */
1515 if ((TREE_CODE (base1
) != TARGET_MEM_REF
1516 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1517 && (TREE_CODE (base2
) != TARGET_MEM_REF
1518 || (!TMR_INDEX (base2
) && !TMR_INDEX2 (base2
)))
1519 && same_type_for_tbaa (TREE_TYPE (ptrtype1
),
1520 TREE_TYPE (ptrtype2
)) == 1
1521 /* But avoid treating arrays as "objects", instead assume they
1522 can overlap by an exact multiple of their element size.
1523 See gcc.dg/torture/alias-2.c. */
1524 && TREE_CODE (TREE_TYPE (ptrtype1
)) != ARRAY_TYPE
)
1525 return ranges_maybe_overlap_p (offset1
, max_size1
, offset2
, max_size2
);
1528 && nonoverlapping_component_refs_p (ref1
, ref2
))
1531 /* Do access-path based disambiguation. */
1533 && (handled_component_p (ref1
) || handled_component_p (ref2
)))
1534 return aliasing_component_refs_p (ref1
,
1535 ref1_alias_set
, base1_alias_set
,
1538 ref2_alias_set
, base2_alias_set
,
1539 offset2
, max_size2
, false);
1544 /* Return true, if the two memory references REF1 and REF2 may alias. */
1547 refs_may_alias_p_2 (ao_ref
*ref1
, ao_ref
*ref2
, bool tbaa_p
)
1550 poly_int64 offset1
= 0, offset2
= 0;
1551 poly_int64 max_size1
= -1, max_size2
= -1;
1552 bool var1_p
, var2_p
, ind1_p
, ind2_p
;
1554 gcc_checking_assert ((!ref1
->ref
1555 || TREE_CODE (ref1
->ref
) == SSA_NAME
1556 || DECL_P (ref1
->ref
)
1557 || TREE_CODE (ref1
->ref
) == STRING_CST
1558 || handled_component_p (ref1
->ref
)
1559 || TREE_CODE (ref1
->ref
) == MEM_REF
1560 || TREE_CODE (ref1
->ref
) == TARGET_MEM_REF
)
1562 || TREE_CODE (ref2
->ref
) == SSA_NAME
1563 || DECL_P (ref2
->ref
)
1564 || TREE_CODE (ref2
->ref
) == STRING_CST
1565 || handled_component_p (ref2
->ref
)
1566 || TREE_CODE (ref2
->ref
) == MEM_REF
1567 || TREE_CODE (ref2
->ref
) == TARGET_MEM_REF
));
1569 /* Decompose the references into their base objects and the access. */
1570 base1
= ao_ref_base (ref1
);
1571 offset1
= ref1
->offset
;
1572 max_size1
= ref1
->max_size
;
1573 base2
= ao_ref_base (ref2
);
1574 offset2
= ref2
->offset
;
1575 max_size2
= ref2
->max_size
;
1577 /* We can end up with registers or constants as bases for example from
1578 *D.1663_44 = VIEW_CONVERT_EXPR<struct DB_LSN>(__tmp$B0F64_59);
1579 which is seen as a struct copy. */
1580 if (TREE_CODE (base1
) == SSA_NAME
1581 || TREE_CODE (base1
) == CONST_DECL
1582 || TREE_CODE (base1
) == CONSTRUCTOR
1583 || TREE_CODE (base1
) == ADDR_EXPR
1584 || CONSTANT_CLASS_P (base1
)
1585 || TREE_CODE (base2
) == SSA_NAME
1586 || TREE_CODE (base2
) == CONST_DECL
1587 || TREE_CODE (base2
) == CONSTRUCTOR
1588 || TREE_CODE (base2
) == ADDR_EXPR
1589 || CONSTANT_CLASS_P (base2
))
1592 /* We can end up referring to code via function and label decls.
1593 As we likely do not properly track code aliases conservatively
1595 if (TREE_CODE (base1
) == FUNCTION_DECL
1596 || TREE_CODE (base1
) == LABEL_DECL
1597 || TREE_CODE (base2
) == FUNCTION_DECL
1598 || TREE_CODE (base2
) == LABEL_DECL
)
1601 /* Two volatile accesses always conflict. */
1602 if (ref1
->volatile_p
1603 && ref2
->volatile_p
)
1606 /* Defer to simple offset based disambiguation if we have
1607 references based on two decls. Do this before defering to
1608 TBAA to handle must-alias cases in conformance with the
1609 GCC extension of allowing type-punning through unions. */
1610 var1_p
= DECL_P (base1
);
1611 var2_p
= DECL_P (base2
);
1612 if (var1_p
&& var2_p
)
1613 return decl_refs_may_alias_p (ref1
->ref
, base1
, offset1
, max_size1
,
1614 ref2
->ref
, base2
, offset2
, max_size2
);
1616 /* Handle restrict based accesses.
1617 ??? ao_ref_base strips inner MEM_REF [&decl], recover from that
1619 tree rbase1
= base1
;
1620 tree rbase2
= base2
;
1625 while (handled_component_p (rbase1
))
1626 rbase1
= TREE_OPERAND (rbase1
, 0);
1632 while (handled_component_p (rbase2
))
1633 rbase2
= TREE_OPERAND (rbase2
, 0);
1635 if (rbase1
&& rbase2
1636 && (TREE_CODE (base1
) == MEM_REF
|| TREE_CODE (base1
) == TARGET_MEM_REF
)
1637 && (TREE_CODE (base2
) == MEM_REF
|| TREE_CODE (base2
) == TARGET_MEM_REF
)
1638 /* If the accesses are in the same restrict clique... */
1639 && MR_DEPENDENCE_CLIQUE (base1
) == MR_DEPENDENCE_CLIQUE (base2
)
1640 /* But based on different pointers they do not alias. */
1641 && MR_DEPENDENCE_BASE (base1
) != MR_DEPENDENCE_BASE (base2
))
1644 ind1_p
= (TREE_CODE (base1
) == MEM_REF
1645 || TREE_CODE (base1
) == TARGET_MEM_REF
);
1646 ind2_p
= (TREE_CODE (base2
) == MEM_REF
1647 || TREE_CODE (base2
) == TARGET_MEM_REF
);
1649 /* Canonicalize the pointer-vs-decl case. */
1650 if (ind1_p
&& var2_p
)
1652 std::swap (offset1
, offset2
);
1653 std::swap (max_size1
, max_size2
);
1654 std::swap (base1
, base2
);
1655 std::swap (ref1
, ref2
);
1662 /* First defer to TBAA if possible. */
1664 && flag_strict_aliasing
1665 && !alias_sets_conflict_p (ao_ref_alias_set (ref1
),
1666 ao_ref_alias_set (ref2
)))
1669 /* If the reference is based on a pointer that points to memory
1670 that may not be written to then the other reference cannot possibly
1672 if ((TREE_CODE (TREE_OPERAND (base2
, 0)) == SSA_NAME
1673 && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base2
, 0)))
1675 && TREE_CODE (TREE_OPERAND (base1
, 0)) == SSA_NAME
1676 && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base1
, 0))))
1679 /* Dispatch to the pointer-vs-decl or pointer-vs-pointer disambiguators. */
1680 if (var1_p
&& ind2_p
)
1681 return indirect_ref_may_alias_decl_p (ref2
->ref
, base2
,
1683 ao_ref_alias_set (ref2
),
1684 ao_ref_base_alias_set (ref2
),
1687 ao_ref_alias_set (ref1
),
1688 ao_ref_base_alias_set (ref1
),
1690 else if (ind1_p
&& ind2_p
)
1691 return indirect_refs_may_alias_p (ref1
->ref
, base1
,
1693 ao_ref_alias_set (ref1
),
1694 ao_ref_base_alias_set (ref1
),
1697 ao_ref_alias_set (ref2
),
1698 ao_ref_base_alias_set (ref2
),
1704 /* Return true, if the two memory references REF1 and REF2 may alias
1705 and update statistics. */
1708 refs_may_alias_p_1 (ao_ref
*ref1
, ao_ref
*ref2
, bool tbaa_p
)
1710 bool res
= refs_may_alias_p_2 (ref1
, ref2
, tbaa_p
);
1712 ++alias_stats
.refs_may_alias_p_may_alias
;
1714 ++alias_stats
.refs_may_alias_p_no_alias
;
1719 refs_may_alias_p (tree ref1
, ao_ref
*ref2
, bool tbaa_p
)
1722 ao_ref_init (&r1
, ref1
);
1723 return refs_may_alias_p_1 (&r1
, ref2
, tbaa_p
);
1727 refs_may_alias_p (tree ref1
, tree ref2
, bool tbaa_p
)
1730 ao_ref_init (&r1
, ref1
);
1731 ao_ref_init (&r2
, ref2
);
1732 return refs_may_alias_p_1 (&r1
, &r2
, tbaa_p
);
1735 /* Returns true if there is a anti-dependence for the STORE that
1736 executes after the LOAD. */
1739 refs_anti_dependent_p (tree load
, tree store
)
1742 ao_ref_init (&r1
, load
);
1743 ao_ref_init (&r2
, store
);
1744 return refs_may_alias_p_1 (&r1
, &r2
, false);
1747 /* Returns true if there is a output dependence for the stores
1748 STORE1 and STORE2. */
1751 refs_output_dependent_p (tree store1
, tree store2
)
1754 ao_ref_init (&r1
, store1
);
1755 ao_ref_init (&r2
, store2
);
1756 return refs_may_alias_p_1 (&r1
, &r2
, false);
1759 /* If the call CALL may use the memory reference REF return true,
1760 otherwise return false. */
1763 ref_maybe_used_by_call_p_1 (gcall
*call
, ao_ref
*ref
, bool tbaa_p
)
1767 int flags
= gimple_call_flags (call
);
1769 /* Const functions without a static chain do not implicitly use memory. */
1770 if (!gimple_call_chain (call
)
1771 && (flags
& (ECF_CONST
|ECF_NOVOPS
)))
1774 base
= ao_ref_base (ref
);
1778 /* A call that is not without side-effects might involve volatile
1779 accesses and thus conflicts with all other volatile accesses. */
1780 if (ref
->volatile_p
)
1783 /* If the reference is based on a decl that is not aliased the call
1784 cannot possibly use it. */
1786 && !may_be_aliased (base
)
1787 /* But local statics can be used through recursion. */
1788 && !is_global_var (base
))
1791 callee
= gimple_call_fndecl (call
);
1793 /* Handle those builtin functions explicitly that do not act as
1794 escape points. See tree-ssa-structalias.c:find_func_aliases
1795 for the list of builtins we might need to handle here. */
1796 if (callee
!= NULL_TREE
1797 && gimple_call_builtin_p (call
, BUILT_IN_NORMAL
))
1798 switch (DECL_FUNCTION_CODE (callee
))
1800 /* All the following functions read memory pointed to by
1801 their second argument. strcat/strncat additionally
1802 reads memory pointed to by the first argument. */
1803 case BUILT_IN_STRCAT
:
1804 case BUILT_IN_STRNCAT
:
1807 ao_ref_init_from_ptr_and_size (&dref
,
1808 gimple_call_arg (call
, 0),
1810 if (refs_may_alias_p_1 (&dref
, ref
, false))
1814 case BUILT_IN_STRCPY
:
1815 case BUILT_IN_STRNCPY
:
1816 case BUILT_IN_MEMCPY
:
1817 case BUILT_IN_MEMMOVE
:
1818 case BUILT_IN_MEMPCPY
:
1819 case BUILT_IN_STPCPY
:
1820 case BUILT_IN_STPNCPY
:
1821 case BUILT_IN_TM_MEMCPY
:
1822 case BUILT_IN_TM_MEMMOVE
:
1825 tree size
= NULL_TREE
;
1826 if (gimple_call_num_args (call
) == 3)
1827 size
= gimple_call_arg (call
, 2);
1828 ao_ref_init_from_ptr_and_size (&dref
,
1829 gimple_call_arg (call
, 1),
1831 return refs_may_alias_p_1 (&dref
, ref
, false);
1833 case BUILT_IN_STRCAT_CHK
:
1834 case BUILT_IN_STRNCAT_CHK
:
1837 ao_ref_init_from_ptr_and_size (&dref
,
1838 gimple_call_arg (call
, 0),
1840 if (refs_may_alias_p_1 (&dref
, ref
, false))
1844 case BUILT_IN_STRCPY_CHK
:
1845 case BUILT_IN_STRNCPY_CHK
:
1846 case BUILT_IN_MEMCPY_CHK
:
1847 case BUILT_IN_MEMMOVE_CHK
:
1848 case BUILT_IN_MEMPCPY_CHK
:
1849 case BUILT_IN_STPCPY_CHK
:
1850 case BUILT_IN_STPNCPY_CHK
:
1853 tree size
= NULL_TREE
;
1854 if (gimple_call_num_args (call
) == 4)
1855 size
= gimple_call_arg (call
, 2);
1856 ao_ref_init_from_ptr_and_size (&dref
,
1857 gimple_call_arg (call
, 1),
1859 return refs_may_alias_p_1 (&dref
, ref
, false);
1861 case BUILT_IN_BCOPY
:
1864 tree size
= gimple_call_arg (call
, 2);
1865 ao_ref_init_from_ptr_and_size (&dref
,
1866 gimple_call_arg (call
, 0),
1868 return refs_may_alias_p_1 (&dref
, ref
, false);
1871 /* The following functions read memory pointed to by their
1873 CASE_BUILT_IN_TM_LOAD (1):
1874 CASE_BUILT_IN_TM_LOAD (2):
1875 CASE_BUILT_IN_TM_LOAD (4):
1876 CASE_BUILT_IN_TM_LOAD (8):
1877 CASE_BUILT_IN_TM_LOAD (FLOAT
):
1878 CASE_BUILT_IN_TM_LOAD (DOUBLE
):
1879 CASE_BUILT_IN_TM_LOAD (LDOUBLE
):
1880 CASE_BUILT_IN_TM_LOAD (M64
):
1881 CASE_BUILT_IN_TM_LOAD (M128
):
1882 CASE_BUILT_IN_TM_LOAD (M256
):
1883 case BUILT_IN_TM_LOG
:
1884 case BUILT_IN_TM_LOG_1
:
1885 case BUILT_IN_TM_LOG_2
:
1886 case BUILT_IN_TM_LOG_4
:
1887 case BUILT_IN_TM_LOG_8
:
1888 case BUILT_IN_TM_LOG_FLOAT
:
1889 case BUILT_IN_TM_LOG_DOUBLE
:
1890 case BUILT_IN_TM_LOG_LDOUBLE
:
1891 case BUILT_IN_TM_LOG_M64
:
1892 case BUILT_IN_TM_LOG_M128
:
1893 case BUILT_IN_TM_LOG_M256
:
1894 return ptr_deref_may_alias_ref_p_1 (gimple_call_arg (call
, 0), ref
);
1896 /* These read memory pointed to by the first argument. */
1897 case BUILT_IN_STRDUP
:
1898 case BUILT_IN_STRNDUP
:
1899 case BUILT_IN_REALLOC
:
1902 tree size
= NULL_TREE
;
1903 if (gimple_call_num_args (call
) == 2)
1904 size
= gimple_call_arg (call
, 1);
1905 ao_ref_init_from_ptr_and_size (&dref
,
1906 gimple_call_arg (call
, 0),
1908 return refs_may_alias_p_1 (&dref
, ref
, false);
1910 /* These read memory pointed to by the first argument. */
1911 case BUILT_IN_INDEX
:
1912 case BUILT_IN_STRCHR
:
1913 case BUILT_IN_STRRCHR
:
1916 ao_ref_init_from_ptr_and_size (&dref
,
1917 gimple_call_arg (call
, 0),
1919 return refs_may_alias_p_1 (&dref
, ref
, false);
1921 /* These read memory pointed to by the first argument with size
1922 in the third argument. */
1923 case BUILT_IN_MEMCHR
:
1926 ao_ref_init_from_ptr_and_size (&dref
,
1927 gimple_call_arg (call
, 0),
1928 gimple_call_arg (call
, 2));
1929 return refs_may_alias_p_1 (&dref
, ref
, false);
1931 /* These read memory pointed to by the first and second arguments. */
1932 case BUILT_IN_STRSTR
:
1933 case BUILT_IN_STRPBRK
:
1936 ao_ref_init_from_ptr_and_size (&dref
,
1937 gimple_call_arg (call
, 0),
1939 if (refs_may_alias_p_1 (&dref
, ref
, false))
1941 ao_ref_init_from_ptr_and_size (&dref
,
1942 gimple_call_arg (call
, 1),
1944 return refs_may_alias_p_1 (&dref
, ref
, false);
1947 /* The following builtins do not read from memory. */
1949 case BUILT_IN_MALLOC
:
1950 case BUILT_IN_POSIX_MEMALIGN
:
1951 case BUILT_IN_ALIGNED_ALLOC
:
1952 case BUILT_IN_CALLOC
:
1953 CASE_BUILT_IN_ALLOCA
:
1954 case BUILT_IN_STACK_SAVE
:
1955 case BUILT_IN_STACK_RESTORE
:
1956 case BUILT_IN_MEMSET
:
1957 case BUILT_IN_TM_MEMSET
:
1958 case BUILT_IN_MEMSET_CHK
:
1959 case BUILT_IN_FREXP
:
1960 case BUILT_IN_FREXPF
:
1961 case BUILT_IN_FREXPL
:
1962 case BUILT_IN_GAMMA_R
:
1963 case BUILT_IN_GAMMAF_R
:
1964 case BUILT_IN_GAMMAL_R
:
1965 case BUILT_IN_LGAMMA_R
:
1966 case BUILT_IN_LGAMMAF_R
:
1967 case BUILT_IN_LGAMMAL_R
:
1969 case BUILT_IN_MODFF
:
1970 case BUILT_IN_MODFL
:
1971 case BUILT_IN_REMQUO
:
1972 case BUILT_IN_REMQUOF
:
1973 case BUILT_IN_REMQUOL
:
1974 case BUILT_IN_SINCOS
:
1975 case BUILT_IN_SINCOSF
:
1976 case BUILT_IN_SINCOSL
:
1977 case BUILT_IN_ASSUME_ALIGNED
:
1978 case BUILT_IN_VA_END
:
1980 /* __sync_* builtins and some OpenMP builtins act as threading
1982 #undef DEF_SYNC_BUILTIN
1983 #define DEF_SYNC_BUILTIN(ENUM, NAME, TYPE, ATTRS) case ENUM:
1984 #include "sync-builtins.def"
1985 #undef DEF_SYNC_BUILTIN
1986 case BUILT_IN_GOMP_ATOMIC_START
:
1987 case BUILT_IN_GOMP_ATOMIC_END
:
1988 case BUILT_IN_GOMP_BARRIER
:
1989 case BUILT_IN_GOMP_BARRIER_CANCEL
:
1990 case BUILT_IN_GOMP_TASKWAIT
:
1991 case BUILT_IN_GOMP_TASKGROUP_END
:
1992 case BUILT_IN_GOMP_CRITICAL_START
:
1993 case BUILT_IN_GOMP_CRITICAL_END
:
1994 case BUILT_IN_GOMP_CRITICAL_NAME_START
:
1995 case BUILT_IN_GOMP_CRITICAL_NAME_END
:
1996 case BUILT_IN_GOMP_LOOP_END
:
1997 case BUILT_IN_GOMP_LOOP_END_CANCEL
:
1998 case BUILT_IN_GOMP_ORDERED_START
:
1999 case BUILT_IN_GOMP_ORDERED_END
:
2000 case BUILT_IN_GOMP_SECTIONS_END
:
2001 case BUILT_IN_GOMP_SECTIONS_END_CANCEL
:
2002 case BUILT_IN_GOMP_SINGLE_COPY_START
:
2003 case BUILT_IN_GOMP_SINGLE_COPY_END
:
2007 /* Fallthru to general call handling. */;
2010 /* Check if base is a global static variable that is not read
2012 if (callee
!= NULL_TREE
&& VAR_P (base
) && TREE_STATIC (base
))
2014 struct cgraph_node
*node
= cgraph_node::get (callee
);
2017 /* FIXME: Callee can be an OMP builtin that does not have a call graph
2018 node yet. We should enforce that there are nodes for all decls in the
2019 IL and remove this check instead. */
2021 && (not_read
= ipa_reference_get_not_read_global (node
))
2022 && bitmap_bit_p (not_read
, ipa_reference_var_uid (base
)))
2026 /* Check if the base variable is call-used. */
2029 if (pt_solution_includes (gimple_call_use_set (call
), base
))
2032 else if ((TREE_CODE (base
) == MEM_REF
2033 || TREE_CODE (base
) == TARGET_MEM_REF
)
2034 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
)
2036 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (TREE_OPERAND (base
, 0));
2040 if (pt_solutions_intersect (gimple_call_use_set (call
), &pi
->pt
))
2046 /* Inspect call arguments for passed-by-value aliases. */
2048 for (i
= 0; i
< gimple_call_num_args (call
); ++i
)
2050 tree op
= gimple_call_arg (call
, i
);
2051 int flags
= gimple_call_arg_flags (call
, i
);
2053 if (flags
& EAF_UNUSED
)
2056 if (TREE_CODE (op
) == WITH_SIZE_EXPR
)
2057 op
= TREE_OPERAND (op
, 0);
2059 if (TREE_CODE (op
) != SSA_NAME
2060 && !is_gimple_min_invariant (op
))
2063 ao_ref_init (&r
, op
);
2064 if (refs_may_alias_p_1 (&r
, ref
, tbaa_p
))
2073 ref_maybe_used_by_call_p (gcall
*call
, ao_ref
*ref
, bool tbaa_p
)
2076 res
= ref_maybe_used_by_call_p_1 (call
, ref
, tbaa_p
);
2078 ++alias_stats
.ref_maybe_used_by_call_p_may_alias
;
2080 ++alias_stats
.ref_maybe_used_by_call_p_no_alias
;
2085 /* If the statement STMT may use the memory reference REF return
2086 true, otherwise return false. */
2089 ref_maybe_used_by_stmt_p (gimple
*stmt
, ao_ref
*ref
, bool tbaa_p
)
2091 if (is_gimple_assign (stmt
))
2095 /* All memory assign statements are single. */
2096 if (!gimple_assign_single_p (stmt
))
2099 rhs
= gimple_assign_rhs1 (stmt
);
2100 if (is_gimple_reg (rhs
)
2101 || is_gimple_min_invariant (rhs
)
2102 || gimple_assign_rhs_code (stmt
) == CONSTRUCTOR
)
2105 return refs_may_alias_p (rhs
, ref
, tbaa_p
);
2107 else if (is_gimple_call (stmt
))
2108 return ref_maybe_used_by_call_p (as_a
<gcall
*> (stmt
), ref
, tbaa_p
);
2109 else if (greturn
*return_stmt
= dyn_cast
<greturn
*> (stmt
))
2111 tree retval
= gimple_return_retval (return_stmt
);
2113 && TREE_CODE (retval
) != SSA_NAME
2114 && !is_gimple_min_invariant (retval
)
2115 && refs_may_alias_p (retval
, ref
, tbaa_p
))
2117 /* If ref escapes the function then the return acts as a use. */
2118 tree base
= ao_ref_base (ref
);
2121 else if (DECL_P (base
))
2122 return is_global_var (base
);
2123 else if (TREE_CODE (base
) == MEM_REF
2124 || TREE_CODE (base
) == TARGET_MEM_REF
)
2125 return ptr_deref_may_alias_global_p (TREE_OPERAND (base
, 0));
2133 ref_maybe_used_by_stmt_p (gimple
*stmt
, tree ref
, bool tbaa_p
)
2136 ao_ref_init (&r
, ref
);
2137 return ref_maybe_used_by_stmt_p (stmt
, &r
, tbaa_p
);
2140 /* If the call in statement CALL may clobber the memory reference REF
2141 return true, otherwise return false. */
2144 call_may_clobber_ref_p_1 (gcall
*call
, ao_ref
*ref
)
2149 /* If the call is pure or const it cannot clobber anything. */
2150 if (gimple_call_flags (call
)
2151 & (ECF_PURE
|ECF_CONST
|ECF_LOOPING_CONST_OR_PURE
|ECF_NOVOPS
))
2153 if (gimple_call_internal_p (call
))
2154 switch (gimple_call_internal_fn (call
))
2156 /* Treat these internal calls like ECF_PURE for aliasing,
2157 they don't write to any memory the program should care about.
2158 They have important other side-effects, and read memory,
2159 so can't be ECF_NOVOPS. */
2160 case IFN_UBSAN_NULL
:
2161 case IFN_UBSAN_BOUNDS
:
2162 case IFN_UBSAN_VPTR
:
2163 case IFN_UBSAN_OBJECT_SIZE
:
2165 case IFN_ASAN_CHECK
:
2171 base
= ao_ref_base (ref
);
2175 if (TREE_CODE (base
) == SSA_NAME
2176 || CONSTANT_CLASS_P (base
))
2179 /* A call that is not without side-effects might involve volatile
2180 accesses and thus conflicts with all other volatile accesses. */
2181 if (ref
->volatile_p
)
2184 /* If the reference is based on a decl that is not aliased the call
2185 cannot possibly clobber it. */
2187 && !may_be_aliased (base
)
2188 /* But local non-readonly statics can be modified through recursion
2189 or the call may implement a threading barrier which we must
2190 treat as may-def. */
2191 && (TREE_READONLY (base
)
2192 || !is_global_var (base
)))
2195 /* If the reference is based on a pointer that points to memory
2196 that may not be written to then the call cannot possibly clobber it. */
2197 if ((TREE_CODE (base
) == MEM_REF
2198 || TREE_CODE (base
) == TARGET_MEM_REF
)
2199 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
2200 && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base
, 0)))
2203 callee
= gimple_call_fndecl (call
);
2205 /* Handle those builtin functions explicitly that do not act as
2206 escape points. See tree-ssa-structalias.c:find_func_aliases
2207 for the list of builtins we might need to handle here. */
2208 if (callee
!= NULL_TREE
2209 && gimple_call_builtin_p (call
, BUILT_IN_NORMAL
))
2210 switch (DECL_FUNCTION_CODE (callee
))
2212 /* All the following functions clobber memory pointed to by
2213 their first argument. */
2214 case BUILT_IN_STRCPY
:
2215 case BUILT_IN_STRNCPY
:
2216 case BUILT_IN_MEMCPY
:
2217 case BUILT_IN_MEMMOVE
:
2218 case BUILT_IN_MEMPCPY
:
2219 case BUILT_IN_STPCPY
:
2220 case BUILT_IN_STPNCPY
:
2221 case BUILT_IN_STRCAT
:
2222 case BUILT_IN_STRNCAT
:
2223 case BUILT_IN_MEMSET
:
2224 case BUILT_IN_TM_MEMSET
:
2225 CASE_BUILT_IN_TM_STORE (1):
2226 CASE_BUILT_IN_TM_STORE (2):
2227 CASE_BUILT_IN_TM_STORE (4):
2228 CASE_BUILT_IN_TM_STORE (8):
2229 CASE_BUILT_IN_TM_STORE (FLOAT
):
2230 CASE_BUILT_IN_TM_STORE (DOUBLE
):
2231 CASE_BUILT_IN_TM_STORE (LDOUBLE
):
2232 CASE_BUILT_IN_TM_STORE (M64
):
2233 CASE_BUILT_IN_TM_STORE (M128
):
2234 CASE_BUILT_IN_TM_STORE (M256
):
2235 case BUILT_IN_TM_MEMCPY
:
2236 case BUILT_IN_TM_MEMMOVE
:
2239 tree size
= NULL_TREE
;
2240 /* Don't pass in size for strncat, as the maximum size
2241 is strlen (dest) + n + 1 instead of n, resp.
2242 n + 1 at dest + strlen (dest), but strlen (dest) isn't
2244 if (gimple_call_num_args (call
) == 3
2245 && DECL_FUNCTION_CODE (callee
) != BUILT_IN_STRNCAT
)
2246 size
= gimple_call_arg (call
, 2);
2247 ao_ref_init_from_ptr_and_size (&dref
,
2248 gimple_call_arg (call
, 0),
2250 return refs_may_alias_p_1 (&dref
, ref
, false);
2252 case BUILT_IN_STRCPY_CHK
:
2253 case BUILT_IN_STRNCPY_CHK
:
2254 case BUILT_IN_MEMCPY_CHK
:
2255 case BUILT_IN_MEMMOVE_CHK
:
2256 case BUILT_IN_MEMPCPY_CHK
:
2257 case BUILT_IN_STPCPY_CHK
:
2258 case BUILT_IN_STPNCPY_CHK
:
2259 case BUILT_IN_STRCAT_CHK
:
2260 case BUILT_IN_STRNCAT_CHK
:
2261 case BUILT_IN_MEMSET_CHK
:
2264 tree size
= NULL_TREE
;
2265 /* Don't pass in size for __strncat_chk, as the maximum size
2266 is strlen (dest) + n + 1 instead of n, resp.
2267 n + 1 at dest + strlen (dest), but strlen (dest) isn't
2269 if (gimple_call_num_args (call
) == 4
2270 && DECL_FUNCTION_CODE (callee
) != BUILT_IN_STRNCAT_CHK
)
2271 size
= gimple_call_arg (call
, 2);
2272 ao_ref_init_from_ptr_and_size (&dref
,
2273 gimple_call_arg (call
, 0),
2275 return refs_may_alias_p_1 (&dref
, ref
, false);
2277 case BUILT_IN_BCOPY
:
2280 tree size
= gimple_call_arg (call
, 2);
2281 ao_ref_init_from_ptr_and_size (&dref
,
2282 gimple_call_arg (call
, 1),
2284 return refs_may_alias_p_1 (&dref
, ref
, false);
2286 /* Allocating memory does not have any side-effects apart from
2287 being the definition point for the pointer. */
2288 case BUILT_IN_MALLOC
:
2289 case BUILT_IN_ALIGNED_ALLOC
:
2290 case BUILT_IN_CALLOC
:
2291 case BUILT_IN_STRDUP
:
2292 case BUILT_IN_STRNDUP
:
2293 /* Unix98 specifies that errno is set on allocation failure. */
2295 && targetm
.ref_may_alias_errno (ref
))
2298 case BUILT_IN_STACK_SAVE
:
2299 CASE_BUILT_IN_ALLOCA
:
2300 case BUILT_IN_ASSUME_ALIGNED
:
2302 /* But posix_memalign stores a pointer into the memory pointed to
2303 by its first argument. */
2304 case BUILT_IN_POSIX_MEMALIGN
:
2306 tree ptrptr
= gimple_call_arg (call
, 0);
2308 ao_ref_init_from_ptr_and_size (&dref
, ptrptr
,
2309 TYPE_SIZE_UNIT (ptr_type_node
));
2310 return (refs_may_alias_p_1 (&dref
, ref
, false)
2312 && targetm
.ref_may_alias_errno (ref
)));
2314 /* Freeing memory kills the pointed-to memory. More importantly
2315 the call has to serve as a barrier for moving loads and stores
2318 case BUILT_IN_VA_END
:
2320 tree ptr
= gimple_call_arg (call
, 0);
2321 return ptr_deref_may_alias_ref_p_1 (ptr
, ref
);
2323 /* Realloc serves both as allocation point and deallocation point. */
2324 case BUILT_IN_REALLOC
:
2326 tree ptr
= gimple_call_arg (call
, 0);
2327 /* Unix98 specifies that errno is set on allocation failure. */
2328 return ((flag_errno_math
2329 && targetm
.ref_may_alias_errno (ref
))
2330 || ptr_deref_may_alias_ref_p_1 (ptr
, ref
));
2332 case BUILT_IN_GAMMA_R
:
2333 case BUILT_IN_GAMMAF_R
:
2334 case BUILT_IN_GAMMAL_R
:
2335 case BUILT_IN_LGAMMA_R
:
2336 case BUILT_IN_LGAMMAF_R
:
2337 case BUILT_IN_LGAMMAL_R
:
2339 tree out
= gimple_call_arg (call
, 1);
2340 if (ptr_deref_may_alias_ref_p_1 (out
, ref
))
2342 if (flag_errno_math
)
2346 case BUILT_IN_FREXP
:
2347 case BUILT_IN_FREXPF
:
2348 case BUILT_IN_FREXPL
:
2350 case BUILT_IN_MODFF
:
2351 case BUILT_IN_MODFL
:
2353 tree out
= gimple_call_arg (call
, 1);
2354 return ptr_deref_may_alias_ref_p_1 (out
, ref
);
2356 case BUILT_IN_REMQUO
:
2357 case BUILT_IN_REMQUOF
:
2358 case BUILT_IN_REMQUOL
:
2360 tree out
= gimple_call_arg (call
, 2);
2361 if (ptr_deref_may_alias_ref_p_1 (out
, ref
))
2363 if (flag_errno_math
)
2367 case BUILT_IN_SINCOS
:
2368 case BUILT_IN_SINCOSF
:
2369 case BUILT_IN_SINCOSL
:
2371 tree sin
= gimple_call_arg (call
, 1);
2372 tree cos
= gimple_call_arg (call
, 2);
2373 return (ptr_deref_may_alias_ref_p_1 (sin
, ref
)
2374 || ptr_deref_may_alias_ref_p_1 (cos
, ref
));
2376 /* __sync_* builtins and some OpenMP builtins act as threading
2378 #undef DEF_SYNC_BUILTIN
2379 #define DEF_SYNC_BUILTIN(ENUM, NAME, TYPE, ATTRS) case ENUM:
2380 #include "sync-builtins.def"
2381 #undef DEF_SYNC_BUILTIN
2382 case BUILT_IN_GOMP_ATOMIC_START
:
2383 case BUILT_IN_GOMP_ATOMIC_END
:
2384 case BUILT_IN_GOMP_BARRIER
:
2385 case BUILT_IN_GOMP_BARRIER_CANCEL
:
2386 case BUILT_IN_GOMP_TASKWAIT
:
2387 case BUILT_IN_GOMP_TASKGROUP_END
:
2388 case BUILT_IN_GOMP_CRITICAL_START
:
2389 case BUILT_IN_GOMP_CRITICAL_END
:
2390 case BUILT_IN_GOMP_CRITICAL_NAME_START
:
2391 case BUILT_IN_GOMP_CRITICAL_NAME_END
:
2392 case BUILT_IN_GOMP_LOOP_END
:
2393 case BUILT_IN_GOMP_LOOP_END_CANCEL
:
2394 case BUILT_IN_GOMP_ORDERED_START
:
2395 case BUILT_IN_GOMP_ORDERED_END
:
2396 case BUILT_IN_GOMP_SECTIONS_END
:
2397 case BUILT_IN_GOMP_SECTIONS_END_CANCEL
:
2398 case BUILT_IN_GOMP_SINGLE_COPY_START
:
2399 case BUILT_IN_GOMP_SINGLE_COPY_END
:
2402 /* Fallthru to general call handling. */;
2405 /* Check if base is a global static variable that is not written
2407 if (callee
!= NULL_TREE
&& VAR_P (base
) && TREE_STATIC (base
))
2409 struct cgraph_node
*node
= cgraph_node::get (callee
);
2413 && (not_written
= ipa_reference_get_not_written_global (node
))
2414 && bitmap_bit_p (not_written
, ipa_reference_var_uid (base
)))
2418 /* Check if the base variable is call-clobbered. */
2420 return pt_solution_includes (gimple_call_clobber_set (call
), base
);
2421 else if ((TREE_CODE (base
) == MEM_REF
2422 || TREE_CODE (base
) == TARGET_MEM_REF
)
2423 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
)
2425 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (TREE_OPERAND (base
, 0));
2429 return pt_solutions_intersect (gimple_call_clobber_set (call
), &pi
->pt
);
2435 /* If the call in statement CALL may clobber the memory reference REF
2436 return true, otherwise return false. */
2439 call_may_clobber_ref_p (gcall
*call
, tree ref
)
2443 ao_ref_init (&r
, ref
);
2444 res
= call_may_clobber_ref_p_1 (call
, &r
);
2446 ++alias_stats
.call_may_clobber_ref_p_may_alias
;
2448 ++alias_stats
.call_may_clobber_ref_p_no_alias
;
2453 /* If the statement STMT may clobber the memory reference REF return true,
2454 otherwise return false. */
2457 stmt_may_clobber_ref_p_1 (gimple
*stmt
, ao_ref
*ref
, bool tbaa_p
)
2459 if (is_gimple_call (stmt
))
2461 tree lhs
= gimple_call_lhs (stmt
);
2463 && TREE_CODE (lhs
) != SSA_NAME
)
2466 ao_ref_init (&r
, lhs
);
2467 if (refs_may_alias_p_1 (ref
, &r
, tbaa_p
))
2471 return call_may_clobber_ref_p_1 (as_a
<gcall
*> (stmt
), ref
);
2473 else if (gimple_assign_single_p (stmt
))
2475 tree lhs
= gimple_assign_lhs (stmt
);
2476 if (TREE_CODE (lhs
) != SSA_NAME
)
2479 ao_ref_init (&r
, lhs
);
2480 return refs_may_alias_p_1 (ref
, &r
, tbaa_p
);
2483 else if (gimple_code (stmt
) == GIMPLE_ASM
)
2490 stmt_may_clobber_ref_p (gimple
*stmt
, tree ref
, bool tbaa_p
)
2493 ao_ref_init (&r
, ref
);
2494 return stmt_may_clobber_ref_p_1 (stmt
, &r
, tbaa_p
);
2497 /* Return true if store1 and store2 described by corresponding tuples
2498 <BASE, OFFSET, SIZE, MAX_SIZE> have the same size and store to the same
2502 same_addr_size_stores_p (tree base1
, poly_int64 offset1
, poly_int64 size1
,
2503 poly_int64 max_size1
,
2504 tree base2
, poly_int64 offset2
, poly_int64 size2
,
2505 poly_int64 max_size2
)
2507 /* Offsets need to be 0. */
2508 if (maybe_ne (offset1
, 0)
2509 || maybe_ne (offset2
, 0))
2512 bool base1_obj_p
= SSA_VAR_P (base1
);
2513 bool base2_obj_p
= SSA_VAR_P (base2
);
2515 /* We need one object. */
2516 if (base1_obj_p
== base2_obj_p
)
2518 tree obj
= base1_obj_p
? base1
: base2
;
2520 /* And we need one MEM_REF. */
2521 bool base1_memref_p
= TREE_CODE (base1
) == MEM_REF
;
2522 bool base2_memref_p
= TREE_CODE (base2
) == MEM_REF
;
2523 if (base1_memref_p
== base2_memref_p
)
2525 tree memref
= base1_memref_p
? base1
: base2
;
2527 /* Sizes need to be valid. */
2528 if (!known_size_p (max_size1
)
2529 || !known_size_p (max_size2
)
2530 || !known_size_p (size1
)
2531 || !known_size_p (size2
))
2534 /* Max_size needs to match size. */
2535 if (maybe_ne (max_size1
, size1
)
2536 || maybe_ne (max_size2
, size2
))
2539 /* Sizes need to match. */
2540 if (maybe_ne (size1
, size2
))
2544 /* Check that memref is a store to pointer with singleton points-to info. */
2545 if (!integer_zerop (TREE_OPERAND (memref
, 1)))
2547 tree ptr
= TREE_OPERAND (memref
, 0);
2548 if (TREE_CODE (ptr
) != SSA_NAME
)
2550 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (ptr
);
2551 unsigned int pt_uid
;
2553 || !pt_solution_singleton_or_null_p (&pi
->pt
, &pt_uid
))
2556 /* Be conservative with non-call exceptions when the address might
2558 if (cfun
->can_throw_non_call_exceptions
&& pi
->pt
.null
)
2561 /* Check that ptr points relative to obj. */
2562 unsigned int obj_uid
= DECL_PT_UID (obj
);
2563 if (obj_uid
!= pt_uid
)
2566 /* Check that the object size is the same as the store size. That ensures us
2567 that ptr points to the start of obj. */
2568 return (DECL_SIZE (obj
)
2569 && poly_int_tree_p (DECL_SIZE (obj
))
2570 && known_eq (wi::to_poly_offset (DECL_SIZE (obj
)), size1
));
2573 /* If STMT kills the memory reference REF return true, otherwise
2577 stmt_kills_ref_p (gimple
*stmt
, ao_ref
*ref
)
2579 if (!ao_ref_base (ref
))
2582 if (gimple_has_lhs (stmt
)
2583 && TREE_CODE (gimple_get_lhs (stmt
)) != SSA_NAME
2584 /* The assignment is not necessarily carried out if it can throw
2585 and we can catch it in the current function where we could inspect
2587 ??? We only need to care about the RHS throwing. For aggregate
2588 assignments or similar calls and non-call exceptions the LHS
2589 might throw as well. */
2590 && !stmt_can_throw_internal (cfun
, stmt
))
2592 tree lhs
= gimple_get_lhs (stmt
);
2593 /* If LHS is literally a base of the access we are done. */
2596 tree base
= ref
->ref
;
2597 tree innermost_dropped_array_ref
= NULL_TREE
;
2598 if (handled_component_p (base
))
2600 tree saved_lhs0
= NULL_TREE
;
2601 if (handled_component_p (lhs
))
2603 saved_lhs0
= TREE_OPERAND (lhs
, 0);
2604 TREE_OPERAND (lhs
, 0) = integer_zero_node
;
2608 /* Just compare the outermost handled component, if
2609 they are equal we have found a possible common
2611 tree saved_base0
= TREE_OPERAND (base
, 0);
2612 TREE_OPERAND (base
, 0) = integer_zero_node
;
2613 bool res
= operand_equal_p (lhs
, base
, 0);
2614 TREE_OPERAND (base
, 0) = saved_base0
;
2617 /* Remember if we drop an array-ref that we need to
2618 double-check not being at struct end. */
2619 if (TREE_CODE (base
) == ARRAY_REF
2620 || TREE_CODE (base
) == ARRAY_RANGE_REF
)
2621 innermost_dropped_array_ref
= base
;
2622 /* Otherwise drop handled components of the access. */
2625 while (handled_component_p (base
));
2627 TREE_OPERAND (lhs
, 0) = saved_lhs0
;
2629 /* Finally check if the lhs has the same address and size as the
2630 base candidate of the access. Watch out if we have dropped
2631 an array-ref that was at struct end, this means ref->ref may
2632 be outside of the TYPE_SIZE of its base. */
2633 if ((! innermost_dropped_array_ref
2634 || ! array_at_struct_end_p (innermost_dropped_array_ref
))
2636 || (((TYPE_SIZE (TREE_TYPE (lhs
))
2637 == TYPE_SIZE (TREE_TYPE (base
)))
2638 || (TYPE_SIZE (TREE_TYPE (lhs
))
2639 && TYPE_SIZE (TREE_TYPE (base
))
2640 && operand_equal_p (TYPE_SIZE (TREE_TYPE (lhs
)),
2641 TYPE_SIZE (TREE_TYPE (base
)),
2643 && operand_equal_p (lhs
, base
,
2645 | OEP_MATCH_SIDE_EFFECTS
))))
2649 /* Now look for non-literal equal bases with the restriction of
2650 handling constant offset and size. */
2651 /* For a must-alias check we need to be able to constrain
2652 the access properly. */
2653 if (!ref
->max_size_known_p ())
2655 poly_int64 size
, offset
, max_size
, ref_offset
= ref
->offset
;
2657 tree base
= get_ref_base_and_extent (lhs
, &offset
, &size
, &max_size
,
2659 /* We can get MEM[symbol: sZ, index: D.8862_1] here,
2660 so base == ref->base does not always hold. */
2661 if (base
!= ref
->base
)
2663 /* Try using points-to info. */
2664 if (same_addr_size_stores_p (base
, offset
, size
, max_size
, ref
->base
,
2665 ref
->offset
, ref
->size
, ref
->max_size
))
2668 /* If both base and ref->base are MEM_REFs, only compare the
2669 first operand, and if the second operand isn't equal constant,
2670 try to add the offsets into offset and ref_offset. */
2671 if (TREE_CODE (base
) == MEM_REF
&& TREE_CODE (ref
->base
) == MEM_REF
2672 && TREE_OPERAND (base
, 0) == TREE_OPERAND (ref
->base
, 0))
2674 if (!tree_int_cst_equal (TREE_OPERAND (base
, 1),
2675 TREE_OPERAND (ref
->base
, 1)))
2677 poly_offset_int off1
= mem_ref_offset (base
);
2678 off1
<<= LOG2_BITS_PER_UNIT
;
2680 poly_offset_int off2
= mem_ref_offset (ref
->base
);
2681 off2
<<= LOG2_BITS_PER_UNIT
;
2683 if (!off1
.to_shwi (&offset
) || !off2
.to_shwi (&ref_offset
))
2690 /* For a must-alias check we need to be able to constrain
2691 the access properly. */
2692 if (known_eq (size
, max_size
)
2693 && known_subrange_p (ref_offset
, ref
->max_size
, offset
, size
))
2697 if (is_gimple_call (stmt
))
2699 tree callee
= gimple_call_fndecl (stmt
);
2700 if (callee
!= NULL_TREE
2701 && gimple_call_builtin_p (stmt
, BUILT_IN_NORMAL
))
2702 switch (DECL_FUNCTION_CODE (callee
))
2706 tree ptr
= gimple_call_arg (stmt
, 0);
2707 tree base
= ao_ref_base (ref
);
2708 if (base
&& TREE_CODE (base
) == MEM_REF
2709 && TREE_OPERAND (base
, 0) == ptr
)
2714 case BUILT_IN_MEMCPY
:
2715 case BUILT_IN_MEMPCPY
:
2716 case BUILT_IN_MEMMOVE
:
2717 case BUILT_IN_MEMSET
:
2718 case BUILT_IN_MEMCPY_CHK
:
2719 case BUILT_IN_MEMPCPY_CHK
:
2720 case BUILT_IN_MEMMOVE_CHK
:
2721 case BUILT_IN_MEMSET_CHK
:
2722 case BUILT_IN_STRNCPY
:
2723 case BUILT_IN_STPNCPY
:
2725 /* For a must-alias check we need to be able to constrain
2726 the access properly. */
2727 if (!ref
->max_size_known_p ())
2729 tree dest
= gimple_call_arg (stmt
, 0);
2730 tree len
= gimple_call_arg (stmt
, 2);
2731 if (!poly_int_tree_p (len
))
2733 tree rbase
= ref
->base
;
2734 poly_offset_int roffset
= ref
->offset
;
2736 ao_ref_init_from_ptr_and_size (&dref
, dest
, len
);
2737 tree base
= ao_ref_base (&dref
);
2738 poly_offset_int offset
= dref
.offset
;
2739 if (!base
|| !known_size_p (dref
.size
))
2741 if (TREE_CODE (base
) == MEM_REF
)
2743 if (TREE_CODE (rbase
) != MEM_REF
)
2745 // Compare pointers.
2746 offset
+= mem_ref_offset (base
) << LOG2_BITS_PER_UNIT
;
2747 roffset
+= mem_ref_offset (rbase
) << LOG2_BITS_PER_UNIT
;
2748 base
= TREE_OPERAND (base
, 0);
2749 rbase
= TREE_OPERAND (rbase
, 0);
2752 && known_subrange_p (roffset
, ref
->max_size
, offset
,
2753 wi::to_poly_offset (len
)
2754 << LOG2_BITS_PER_UNIT
))
2759 case BUILT_IN_VA_END
:
2761 tree ptr
= gimple_call_arg (stmt
, 0);
2762 if (TREE_CODE (ptr
) == ADDR_EXPR
)
2764 tree base
= ao_ref_base (ref
);
2765 if (TREE_OPERAND (ptr
, 0) == base
)
2778 stmt_kills_ref_p (gimple
*stmt
, tree ref
)
2781 ao_ref_init (&r
, ref
);
2782 return stmt_kills_ref_p (stmt
, &r
);
2786 /* Walk the virtual use-def chain of VUSE until hitting the virtual operand
2787 TARGET or a statement clobbering the memory reference REF in which
2788 case false is returned. The walk starts with VUSE, one argument of PHI. */
2791 maybe_skip_until (gimple
*phi
, tree
&target
, basic_block target_bb
,
2792 ao_ref
*ref
, tree vuse
, unsigned int &limit
, bitmap
*visited
,
2793 bool abort_on_visited
,
2794 void *(*translate
)(ao_ref
*, tree
, void *, bool *),
2797 basic_block bb
= gimple_bb (phi
);
2800 *visited
= BITMAP_ALLOC (NULL
);
2802 bitmap_set_bit (*visited
, SSA_NAME_VERSION (PHI_RESULT (phi
)));
2804 /* Walk until we hit the target. */
2805 while (vuse
!= target
)
2807 gimple
*def_stmt
= SSA_NAME_DEF_STMT (vuse
);
2808 /* If we are searching for the target VUSE by walking up to
2809 TARGET_BB dominating the original PHI we are finished once
2810 we reach a default def or a definition in a block dominating
2811 that block. Update TARGET and return. */
2813 && (gimple_nop_p (def_stmt
)
2814 || dominated_by_p (CDI_DOMINATORS
,
2815 target_bb
, gimple_bb (def_stmt
))))
2821 /* Recurse for PHI nodes. */
2822 if (gimple_code (def_stmt
) == GIMPLE_PHI
)
2824 /* An already visited PHI node ends the walk successfully. */
2825 if (bitmap_bit_p (*visited
, SSA_NAME_VERSION (PHI_RESULT (def_stmt
))))
2826 return !abort_on_visited
;
2827 vuse
= get_continuation_for_phi (def_stmt
, ref
, limit
,
2828 visited
, abort_on_visited
,
2834 else if (gimple_nop_p (def_stmt
))
2838 /* A clobbering statement or the end of the IL ends it failing. */
2839 if ((int)limit
<= 0)
2842 if (stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
2844 bool disambiguate_only
= true;
2846 && (*translate
) (ref
, vuse
, data
, &disambiguate_only
) == NULL
)
2852 /* If we reach a new basic-block see if we already skipped it
2853 in a previous walk that ended successfully. */
2854 if (gimple_bb (def_stmt
) != bb
)
2856 if (!bitmap_set_bit (*visited
, SSA_NAME_VERSION (vuse
)))
2857 return !abort_on_visited
;
2858 bb
= gimple_bb (def_stmt
);
2860 vuse
= gimple_vuse (def_stmt
);
2866 /* Starting from a PHI node for the virtual operand of the memory reference
2867 REF find a continuation virtual operand that allows to continue walking
2868 statements dominating PHI skipping only statements that cannot possibly
2869 clobber REF. Decrements LIMIT for each alias disambiguation done
2870 and aborts the walk, returning NULL_TREE if it reaches zero.
2871 Returns NULL_TREE if no suitable virtual operand can be found. */
2874 get_continuation_for_phi (gimple
*phi
, ao_ref
*ref
,
2875 unsigned int &limit
, bitmap
*visited
,
2876 bool abort_on_visited
,
2877 void *(*translate
)(ao_ref
*, tree
, void *, bool *),
2880 unsigned nargs
= gimple_phi_num_args (phi
);
2882 /* Through a single-argument PHI we can simply look through. */
2884 return PHI_ARG_DEF (phi
, 0);
2886 /* For two or more arguments try to pairwise skip non-aliasing code
2887 until we hit the phi argument definition that dominates the other one. */
2888 basic_block phi_bb
= gimple_bb (phi
);
2892 /* Find a candidate for the virtual operand which definition
2893 dominates those of all others. */
2894 /* First look if any of the args themselves satisfy this. */
2895 for (i
= 0; i
< nargs
; ++i
)
2897 arg0
= PHI_ARG_DEF (phi
, i
);
2898 if (SSA_NAME_IS_DEFAULT_DEF (arg0
))
2900 basic_block def_bb
= gimple_bb (SSA_NAME_DEF_STMT (arg0
));
2901 if (def_bb
!= phi_bb
2902 && dominated_by_p (CDI_DOMINATORS
, phi_bb
, def_bb
))
2906 /* If not, look if we can reach such candidate by walking defs
2907 until we hit the immediate dominator. maybe_skip_until will
2909 basic_block dom
= get_immediate_dominator (CDI_DOMINATORS
, phi_bb
);
2911 /* Then check against the (to be) found candidate. */
2912 for (i
= 0; i
< nargs
; ++i
)
2914 arg1
= PHI_ARG_DEF (phi
, i
);
2917 else if (! maybe_skip_until (phi
, arg0
, dom
, ref
, arg1
, limit
, visited
,
2919 /* Do not translate when walking over
2923 gimple_bb (SSA_NAME_DEF_STMT (arg1
)),
2925 ? NULL
: translate
, data
))
2932 /* Based on the memory reference REF and its virtual use VUSE call
2933 WALKER for each virtual use that is equivalent to VUSE, including VUSE
2934 itself. That is, for each virtual use for which its defining statement
2935 does not clobber REF.
2937 WALKER is called with REF, the current virtual use and DATA. If
2938 WALKER returns non-NULL the walk stops and its result is returned.
2939 At the end of a non-successful walk NULL is returned.
2941 TRANSLATE if non-NULL is called with a pointer to REF, the virtual
2942 use which definition is a statement that may clobber REF and DATA.
2943 If TRANSLATE returns (void *)-1 the walk stops and NULL is returned.
2944 If TRANSLATE returns non-NULL the walk stops and its result is returned.
2945 If TRANSLATE returns NULL the walk continues and TRANSLATE is supposed
2946 to adjust REF and *DATA to make that valid.
2948 VALUEIZE if non-NULL is called with the next VUSE that is considered
2949 and return value is substituted for that. This can be used to
2950 implement optimistic value-numbering for example. Note that the
2951 VUSE argument is assumed to be valueized already.
2953 LIMIT specifies the number of alias queries we are allowed to do,
2954 the walk stops when it reaches zero and NULL is returned. LIMIT
2955 is decremented by the number of alias queries (plus adjustments
2956 done by the callbacks) upon return.
2958 TODO: Cache the vector of equivalent vuses per ref, vuse pair. */
2961 walk_non_aliased_vuses (ao_ref
*ref
, tree vuse
,
2962 void *(*walker
)(ao_ref
*, tree
, void *),
2963 void *(*translate
)(ao_ref
*, tree
, void *, bool *),
2964 tree (*valueize
)(tree
),
2965 unsigned &limit
, void *data
)
2967 bitmap visited
= NULL
;
2969 bool translated
= false;
2971 timevar_push (TV_ALIAS_STMT_WALK
);
2977 /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */
2978 res
= (*walker
) (ref
, vuse
, data
);
2980 if (res
== (void *)-1)
2985 /* Lookup succeeded. */
2986 else if (res
!= NULL
)
2991 vuse
= valueize (vuse
);
2998 def_stmt
= SSA_NAME_DEF_STMT (vuse
);
2999 if (gimple_nop_p (def_stmt
))
3001 else if (gimple_code (def_stmt
) == GIMPLE_PHI
)
3002 vuse
= get_continuation_for_phi (def_stmt
, ref
, limit
,
3003 &visited
, translated
, translate
, data
);
3006 if ((int)limit
<= 0)
3011 if (stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
3015 bool disambiguate_only
= false;
3016 res
= (*translate
) (ref
, vuse
, data
, &disambiguate_only
);
3017 /* Failed lookup and translation. */
3018 if (res
== (void *)-1)
3023 /* Lookup succeeded. */
3024 else if (res
!= NULL
)
3026 /* Translation succeeded, continue walking. */
3027 translated
= translated
|| !disambiguate_only
;
3029 vuse
= gimple_vuse (def_stmt
);
3035 BITMAP_FREE (visited
);
3037 timevar_pop (TV_ALIAS_STMT_WALK
);
3043 /* Based on the memory reference REF call WALKER for each vdef which
3044 defining statement may clobber REF, starting with VDEF. If REF
3045 is NULL_TREE, each defining statement is visited.
3047 WALKER is called with REF, the current vdef and DATA. If WALKER
3048 returns true the walk is stopped, otherwise it continues.
3050 If function entry is reached, FUNCTION_ENTRY_REACHED is set to true.
3051 The pointer may be NULL and then we do not track this information.
3053 At PHI nodes walk_aliased_vdefs forks into one walk for reach
3054 PHI argument (but only one walk continues on merge points), the
3055 return value is true if any of the walks was successful.
3057 The function returns the number of statements walked or -1 if
3058 LIMIT stmts were walked and the walk was aborted at this point.
3059 If LIMIT is zero the walk is not aborted. */
3062 walk_aliased_vdefs_1 (ao_ref
*ref
, tree vdef
,
3063 bool (*walker
)(ao_ref
*, tree
, void *), void *data
,
3064 bitmap
*visited
, unsigned int cnt
,
3065 bool *function_entry_reached
, unsigned limit
)
3069 gimple
*def_stmt
= SSA_NAME_DEF_STMT (vdef
);
3072 && !bitmap_set_bit (*visited
, SSA_NAME_VERSION (vdef
)))
3075 if (gimple_nop_p (def_stmt
))
3077 if (function_entry_reached
)
3078 *function_entry_reached
= true;
3081 else if (gimple_code (def_stmt
) == GIMPLE_PHI
)
3085 *visited
= BITMAP_ALLOC (NULL
);
3086 for (i
= 0; i
< gimple_phi_num_args (def_stmt
); ++i
)
3088 int res
= walk_aliased_vdefs_1 (ref
,
3089 gimple_phi_arg_def (def_stmt
, i
),
3090 walker
, data
, visited
, cnt
,
3091 function_entry_reached
, limit
);
3099 /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */
3104 || stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
3105 && (*walker
) (ref
, vdef
, data
))
3108 vdef
= gimple_vuse (def_stmt
);
3114 walk_aliased_vdefs (ao_ref
*ref
, tree vdef
,
3115 bool (*walker
)(ao_ref
*, tree
, void *), void *data
,
3117 bool *function_entry_reached
, unsigned int limit
)
3119 bitmap local_visited
= NULL
;
3122 timevar_push (TV_ALIAS_STMT_WALK
);
3124 if (function_entry_reached
)
3125 *function_entry_reached
= false;
3127 ret
= walk_aliased_vdefs_1 (ref
, vdef
, walker
, data
,
3128 visited
? visited
: &local_visited
, 0,
3129 function_entry_reached
, limit
);
3131 BITMAP_FREE (local_visited
);
3133 timevar_pop (TV_ALIAS_STMT_WALK
);