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 /* Determine if the two component references REF1 and REF2 which are
826 based on access types TYPE1 and TYPE2 and of which at least one is based
827 on an indirect reference may alias. REF2 is the only one that can
828 be a decl in which case REF2_IS_DECL is true.
829 REF1_ALIAS_SET, BASE1_ALIAS_SET, REF2_ALIAS_SET and BASE2_ALIAS_SET
830 are the respective alias sets. */
833 aliasing_component_refs_p (tree ref1
,
834 alias_set_type ref1_alias_set
,
835 alias_set_type base1_alias_set
,
836 poly_int64 offset1
, poly_int64 max_size1
,
838 alias_set_type ref2_alias_set
,
839 alias_set_type base2_alias_set
,
840 poly_int64 offset2
, poly_int64 max_size2
,
843 /* If one reference is a component references through pointers try to find a
844 common base and apply offset based disambiguation. This handles
846 struct A { int i; int j; } *q;
847 struct B { struct A a; int k; } *p;
848 disambiguating q->i and p->a.j. */
852 int same_p1
= 0, same_p2
= 0;
854 /* Choose bases and base types to search for. */
856 while (handled_component_p (base1
))
857 base1
= TREE_OPERAND (base1
, 0);
858 type1
= TREE_TYPE (base1
);
860 while (handled_component_p (base2
))
861 base2
= TREE_OPERAND (base2
, 0);
862 type2
= TREE_TYPE (base2
);
864 /* Now search for the type1 in the access path of ref2. This
865 would be a common base for doing offset based disambiguation on.
866 This however only makes sense if type2 is big enough to hold type1. */
867 int cmp_outer
= compare_type_sizes (type2
, type1
);
873 /* We walk from inner type to the outer types. If type we see is
874 already too large to be part of type1, terminate the search. */
875 int cmp
= compare_type_sizes (type1
, TREE_TYPE (*refp
));
878 /* If types may be of same size, see if we can decide about their
882 same_p2
= same_type_for_tbaa (TREE_TYPE (*refp
), type1
);
886 if (!handled_component_p (*refp
))
888 refp
= &TREE_OPERAND (*refp
, 0);
892 poly_int64 offadj
, sztmp
, msztmp
;
894 get_ref_base_and_extent (*refp
, &offadj
, &sztmp
, &msztmp
, &reverse
);
896 get_ref_base_and_extent (base1
, &offadj
, &sztmp
, &msztmp
, &reverse
);
898 if (ranges_maybe_overlap_p (offset1
, max_size1
, offset2
, max_size2
))
900 ++alias_stats
.aliasing_component_refs_p_may_alias
;
905 ++alias_stats
.aliasing_component_refs_p_no_alias
;
911 /* If we didn't find a common base, try the other way around. */
917 int cmp
= compare_type_sizes (type2
, TREE_TYPE (*refp
));
920 /* If types may be of same size, see if we can decide about their
924 same_p1
= same_type_for_tbaa (TREE_TYPE (*refp
), type2
);
928 if (!handled_component_p (*refp
))
930 refp
= &TREE_OPERAND (*refp
, 0);
934 poly_int64 offadj
, sztmp
, msztmp
;
937 get_ref_base_and_extent (*refp
, &offadj
, &sztmp
, &msztmp
, &reverse
);
939 get_ref_base_and_extent (base2
, &offadj
, &sztmp
, &msztmp
, &reverse
);
941 if (ranges_maybe_overlap_p (offset1
, max_size1
, offset2
, max_size2
))
943 ++alias_stats
.aliasing_component_refs_p_may_alias
;
948 ++alias_stats
.aliasing_component_refs_p_no_alias
;
954 /* In the following code we make an assumption that the types in access
955 paths do not overlap and thus accesses alias only if one path can be
956 continuation of another. If we was not able to decide about equivalence,
957 we need to give up. */
958 if (same_p1
== -1 || same_p2
== -1)
961 /* If we have two type access paths B1.path1 and B2.path2 they may
962 only alias if either B1 is in B2.path2 or B2 is in B1.path1.
963 But we can still have a path that goes B1.path1...B2.path2 with
964 a part that we do not see. So we can only disambiguate now
965 if there is no B2 in the tail of path1 and no B1 on the
967 if (compare_type_sizes (TREE_TYPE (ref2
), type1
) >= 0
968 && (base1_alias_set
== ref2_alias_set
969 || alias_set_subset_of (base1_alias_set
, ref2_alias_set
)))
971 ++alias_stats
.aliasing_component_refs_p_may_alias
;
974 /* If this is ptr vs. decl then we know there is no ptr ... decl path. */
976 && compare_type_sizes (TREE_TYPE (ref1
), type2
) >= 0
977 && (base2_alias_set
== ref1_alias_set
978 || alias_set_subset_of (base2_alias_set
, ref1_alias_set
)))
980 ++alias_stats
.aliasing_component_refs_p_may_alias
;
983 ++alias_stats
.aliasing_component_refs_p_no_alias
;
987 /* Return true if we can determine that component references REF1 and REF2,
988 that are within a common DECL, cannot overlap. */
991 nonoverlapping_component_refs_of_decl_p (tree ref1
, tree ref2
)
993 auto_vec
<tree
, 16> component_refs1
;
994 auto_vec
<tree
, 16> component_refs2
;
996 /* Create the stack of handled components for REF1. */
997 while (handled_component_p (ref1
))
999 component_refs1
.safe_push (ref1
);
1000 ref1
= TREE_OPERAND (ref1
, 0);
1002 if (TREE_CODE (ref1
) == MEM_REF
)
1004 if (!integer_zerop (TREE_OPERAND (ref1
, 1)))
1006 ref1
= TREE_OPERAND (TREE_OPERAND (ref1
, 0), 0);
1009 /* Create the stack of handled components for REF2. */
1010 while (handled_component_p (ref2
))
1012 component_refs2
.safe_push (ref2
);
1013 ref2
= TREE_OPERAND (ref2
, 0);
1015 if (TREE_CODE (ref2
) == MEM_REF
)
1017 if (!integer_zerop (TREE_OPERAND (ref2
, 1)))
1019 ref2
= TREE_OPERAND (TREE_OPERAND (ref2
, 0), 0);
1022 /* Bases must be either same or uncomparable. */
1023 gcc_checking_assert (ref1
== ref2
1024 || (DECL_P (ref1
) && DECL_P (ref2
)
1025 && compare_base_decls (ref1
, ref2
) != 0));
1027 /* Pop the stacks in parallel and examine the COMPONENT_REFs of the same
1028 rank. This is sufficient because we start from the same DECL and you
1029 cannot reference several fields at a time with COMPONENT_REFs (unlike
1030 with ARRAY_RANGE_REFs for arrays) so you always need the same number
1031 of them to access a sub-component, unless you're in a union, in which
1032 case the return value will precisely be false. */
1037 if (component_refs1
.is_empty ())
1039 ref1
= component_refs1
.pop ();
1041 while (!RECORD_OR_UNION_TYPE_P (TREE_TYPE (TREE_OPERAND (ref1
, 0))));
1045 if (component_refs2
.is_empty ())
1047 ref2
= component_refs2
.pop ();
1049 while (!RECORD_OR_UNION_TYPE_P (TREE_TYPE (TREE_OPERAND (ref2
, 0))));
1051 /* Beware of BIT_FIELD_REF. */
1052 if (TREE_CODE (ref1
) != COMPONENT_REF
1053 || TREE_CODE (ref2
) != COMPONENT_REF
)
1056 tree field1
= TREE_OPERAND (ref1
, 1);
1057 tree field2
= TREE_OPERAND (ref2
, 1);
1059 /* ??? We cannot simply use the type of operand #0 of the refs here
1060 as the Fortran compiler smuggles type punning into COMPONENT_REFs
1061 for common blocks instead of using unions like everyone else. */
1062 tree type1
= DECL_CONTEXT (field1
);
1063 tree type2
= DECL_CONTEXT (field2
);
1065 /* We cannot disambiguate fields in a union or qualified union. */
1066 if (type1
!= type2
|| TREE_CODE (type1
) != RECORD_TYPE
)
1069 if (field1
!= field2
)
1071 /* A field and its representative need to be considered the
1073 if (DECL_BIT_FIELD_REPRESENTATIVE (field1
) == field2
1074 || DECL_BIT_FIELD_REPRESENTATIVE (field2
) == field1
)
1076 /* Different fields of the same record type cannot overlap.
1077 ??? Bitfields can overlap at RTL level so punt on them. */
1078 if (DECL_BIT_FIELD (field1
) && DECL_BIT_FIELD (field2
))
1087 /* qsort compare function to sort FIELD_DECLs after their
1088 DECL_FIELD_CONTEXT TYPE_UID. */
1091 ncr_compar (const void *field1_
, const void *field2_
)
1093 const_tree field1
= *(const_tree
*) const_cast <void *>(field1_
);
1094 const_tree field2
= *(const_tree
*) const_cast <void *>(field2_
);
1095 unsigned int uid1
= TYPE_UID (DECL_FIELD_CONTEXT (field1
));
1096 unsigned int uid2
= TYPE_UID (DECL_FIELD_CONTEXT (field2
));
1099 else if (uid1
> uid2
)
1104 /* Return true if we can determine that the fields referenced cannot
1105 overlap for any pair of objects. */
1108 nonoverlapping_component_refs_p (const_tree x
, const_tree y
)
1110 if (!flag_strict_aliasing
1112 || TREE_CODE (x
) != COMPONENT_REF
1113 || TREE_CODE (y
) != COMPONENT_REF
)
1116 auto_vec
<const_tree
, 16> fieldsx
;
1117 while (TREE_CODE (x
) == COMPONENT_REF
)
1119 tree field
= TREE_OPERAND (x
, 1);
1120 tree type
= DECL_FIELD_CONTEXT (field
);
1121 if (TREE_CODE (type
) == RECORD_TYPE
)
1122 fieldsx
.safe_push (field
);
1123 x
= TREE_OPERAND (x
, 0);
1125 if (fieldsx
.length () == 0)
1127 auto_vec
<const_tree
, 16> fieldsy
;
1128 while (TREE_CODE (y
) == COMPONENT_REF
)
1130 tree field
= TREE_OPERAND (y
, 1);
1131 tree type
= DECL_FIELD_CONTEXT (field
);
1132 if (TREE_CODE (type
) == RECORD_TYPE
)
1133 fieldsy
.safe_push (TREE_OPERAND (y
, 1));
1134 y
= TREE_OPERAND (y
, 0);
1136 if (fieldsy
.length () == 0)
1139 /* Most common case first. */
1140 if (fieldsx
.length () == 1
1141 && fieldsy
.length () == 1)
1142 return ((DECL_FIELD_CONTEXT (fieldsx
[0])
1143 == DECL_FIELD_CONTEXT (fieldsy
[0]))
1144 && fieldsx
[0] != fieldsy
[0]
1145 && !(DECL_BIT_FIELD (fieldsx
[0]) && DECL_BIT_FIELD (fieldsy
[0])));
1147 if (fieldsx
.length () == 2)
1149 if (ncr_compar (&fieldsx
[0], &fieldsx
[1]) == 1)
1150 std::swap (fieldsx
[0], fieldsx
[1]);
1153 fieldsx
.qsort (ncr_compar
);
1155 if (fieldsy
.length () == 2)
1157 if (ncr_compar (&fieldsy
[0], &fieldsy
[1]) == 1)
1158 std::swap (fieldsy
[0], fieldsy
[1]);
1161 fieldsy
.qsort (ncr_compar
);
1163 unsigned i
= 0, j
= 0;
1166 const_tree fieldx
= fieldsx
[i
];
1167 const_tree fieldy
= fieldsy
[j
];
1168 tree typex
= DECL_FIELD_CONTEXT (fieldx
);
1169 tree typey
= DECL_FIELD_CONTEXT (fieldy
);
1172 /* We're left with accessing different fields of a structure,
1173 no possible overlap. */
1174 if (fieldx
!= fieldy
)
1176 /* A field and its representative need to be considered the
1178 if (DECL_BIT_FIELD_REPRESENTATIVE (fieldx
) == fieldy
1179 || DECL_BIT_FIELD_REPRESENTATIVE (fieldy
) == fieldx
)
1181 /* Different fields of the same record type cannot overlap.
1182 ??? Bitfields can overlap at RTL level so punt on them. */
1183 if (DECL_BIT_FIELD (fieldx
) && DECL_BIT_FIELD (fieldy
))
1188 if (TYPE_UID (typex
) < TYPE_UID (typey
))
1191 if (i
== fieldsx
.length ())
1197 if (j
== fieldsy
.length ())
1207 /* Return true if two memory references based on the variables BASE1
1208 and BASE2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and
1209 [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. REF1 and REF2
1210 if non-NULL are the complete memory reference trees. */
1213 decl_refs_may_alias_p (tree ref1
, tree base1
,
1214 poly_int64 offset1
, poly_int64 max_size1
,
1215 tree ref2
, tree base2
,
1216 poly_int64 offset2
, poly_int64 max_size2
)
1218 gcc_checking_assert (DECL_P (base1
) && DECL_P (base2
));
1220 /* If both references are based on different variables, they cannot alias. */
1221 if (compare_base_decls (base1
, base2
) == 0)
1224 /* If both references are based on the same variable, they cannot alias if
1225 the accesses do not overlap. */
1226 if (!ranges_maybe_overlap_p (offset1
, max_size1
, offset2
, max_size2
))
1229 /* For components with variable position, the above test isn't sufficient,
1230 so we disambiguate component references manually. */
1232 && handled_component_p (ref1
) && handled_component_p (ref2
)
1233 && nonoverlapping_component_refs_of_decl_p (ref1
, ref2
))
1239 /* Return true if an indirect reference based on *PTR1 constrained
1240 to [OFFSET1, OFFSET1 + MAX_SIZE1) may alias a variable based on BASE2
1241 constrained to [OFFSET2, OFFSET2 + MAX_SIZE2). *PTR1 and BASE2 have
1242 the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1
1243 in which case they are computed on-demand. REF1 and REF2
1244 if non-NULL are the complete memory reference trees. */
1247 indirect_ref_may_alias_decl_p (tree ref1 ATTRIBUTE_UNUSED
, tree base1
,
1248 poly_int64 offset1
, poly_int64 max_size1
,
1249 alias_set_type ref1_alias_set
,
1250 alias_set_type base1_alias_set
,
1251 tree ref2 ATTRIBUTE_UNUSED
, tree base2
,
1252 poly_int64 offset2
, poly_int64 max_size2
,
1253 alias_set_type ref2_alias_set
,
1254 alias_set_type base2_alias_set
, bool tbaa_p
)
1257 tree ptrtype1
, dbase2
;
1259 gcc_checking_assert ((TREE_CODE (base1
) == MEM_REF
1260 || TREE_CODE (base1
) == TARGET_MEM_REF
)
1263 ptr1
= TREE_OPERAND (base1
, 0);
1264 poly_offset_int moff
= mem_ref_offset (base1
) << LOG2_BITS_PER_UNIT
;
1266 /* If only one reference is based on a variable, they cannot alias if
1267 the pointer access is beyond the extent of the variable access.
1268 (the pointer base cannot validly point to an offset less than zero
1270 ??? IVOPTs creates bases that do not honor this restriction,
1271 so do not apply this optimization for TARGET_MEM_REFs. */
1272 if (TREE_CODE (base1
) != TARGET_MEM_REF
1273 && !ranges_maybe_overlap_p (offset1
+ moff
, -1, offset2
, max_size2
))
1275 /* They also cannot alias if the pointer may not point to the decl. */
1276 if (!ptr_deref_may_alias_decl_p (ptr1
, base2
))
1279 /* Disambiguations that rely on strict aliasing rules follow. */
1280 if (!flag_strict_aliasing
|| !tbaa_p
)
1283 ptrtype1
= TREE_TYPE (TREE_OPERAND (base1
, 1));
1285 /* If the alias set for a pointer access is zero all bets are off. */
1286 if (base1_alias_set
== 0)
1289 /* When we are trying to disambiguate an access with a pointer dereference
1290 as base versus one with a decl as base we can use both the size
1291 of the decl and its dynamic type for extra disambiguation.
1292 ??? We do not know anything about the dynamic type of the decl
1293 other than that its alias-set contains base2_alias_set as a subset
1294 which does not help us here. */
1295 /* As we know nothing useful about the dynamic type of the decl just
1296 use the usual conflict check rather than a subset test.
1297 ??? We could introduce -fvery-strict-aliasing when the language
1298 does not allow decls to have a dynamic type that differs from their
1299 static type. Then we can check
1300 !alias_set_subset_of (base1_alias_set, base2_alias_set) instead. */
1301 if (base1_alias_set
!= base2_alias_set
1302 && !alias_sets_conflict_p (base1_alias_set
, base2_alias_set
))
1304 /* If the size of the access relevant for TBAA through the pointer
1305 is bigger than the size of the decl we can't possibly access the
1306 decl via that pointer. */
1307 if (/* ??? This in turn may run afoul when a decl of type T which is
1308 a member of union type U is accessed through a pointer to
1309 type U and sizeof T is smaller than sizeof U. */
1310 TREE_CODE (TREE_TYPE (ptrtype1
)) != UNION_TYPE
1311 && TREE_CODE (TREE_TYPE (ptrtype1
)) != QUAL_UNION_TYPE
1312 && compare_sizes (DECL_SIZE (base2
),
1313 TYPE_SIZE (TREE_TYPE (ptrtype1
))) < 0)
1319 /* If the decl is accessed via a MEM_REF, reconstruct the base
1320 we can use for TBAA and an appropriately adjusted offset. */
1322 while (handled_component_p (dbase2
))
1323 dbase2
= TREE_OPERAND (dbase2
, 0);
1324 poly_int64 doffset1
= offset1
;
1325 poly_offset_int doffset2
= offset2
;
1326 if (TREE_CODE (dbase2
) == MEM_REF
1327 || TREE_CODE (dbase2
) == TARGET_MEM_REF
)
1328 doffset2
-= mem_ref_offset (dbase2
) << LOG2_BITS_PER_UNIT
;
1330 /* If either reference is view-converted, give up now. */
1331 if (same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (ptrtype1
)) != 1
1332 || same_type_for_tbaa (TREE_TYPE (dbase2
), TREE_TYPE (base2
)) != 1)
1335 /* If both references are through the same type, they do not alias
1336 if the accesses do not overlap. This does extra disambiguation
1337 for mixed/pointer accesses but requires strict aliasing.
1338 For MEM_REFs we require that the component-ref offset we computed
1339 is relative to the start of the type which we ensure by
1340 comparing rvalue and access type and disregarding the constant
1342 if ((TREE_CODE (base1
) != TARGET_MEM_REF
1343 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1344 && same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (dbase2
)) == 1)
1345 return ranges_maybe_overlap_p (doffset1
, max_size1
, doffset2
, max_size2
);
1348 && nonoverlapping_component_refs_p (ref1
, ref2
))
1351 /* Do access-path based disambiguation. */
1353 && (handled_component_p (ref1
) || handled_component_p (ref2
)))
1354 return aliasing_component_refs_p (ref1
,
1355 ref1_alias_set
, base1_alias_set
,
1358 ref2_alias_set
, base2_alias_set
,
1359 offset2
, max_size2
, true);
1364 /* Return true if two indirect references based on *PTR1
1365 and *PTR2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and
1366 [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. *PTR1 and *PTR2 have
1367 the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1
1368 in which case they are computed on-demand. REF1 and REF2
1369 if non-NULL are the complete memory reference trees. */
1372 indirect_refs_may_alias_p (tree ref1 ATTRIBUTE_UNUSED
, tree base1
,
1373 poly_int64 offset1
, poly_int64 max_size1
,
1374 alias_set_type ref1_alias_set
,
1375 alias_set_type base1_alias_set
,
1376 tree ref2 ATTRIBUTE_UNUSED
, tree base2
,
1377 poly_int64 offset2
, poly_int64 max_size2
,
1378 alias_set_type ref2_alias_set
,
1379 alias_set_type base2_alias_set
, bool tbaa_p
)
1383 tree ptrtype1
, ptrtype2
;
1385 gcc_checking_assert ((TREE_CODE (base1
) == MEM_REF
1386 || TREE_CODE (base1
) == TARGET_MEM_REF
)
1387 && (TREE_CODE (base2
) == MEM_REF
1388 || TREE_CODE (base2
) == TARGET_MEM_REF
));
1390 ptr1
= TREE_OPERAND (base1
, 0);
1391 ptr2
= TREE_OPERAND (base2
, 0);
1393 /* If both bases are based on pointers they cannot alias if they may not
1394 point to the same memory object or if they point to the same object
1395 and the accesses do not overlap. */
1396 if ((!cfun
|| gimple_in_ssa_p (cfun
))
1397 && operand_equal_p (ptr1
, ptr2
, 0)
1398 && (((TREE_CODE (base1
) != TARGET_MEM_REF
1399 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1400 && (TREE_CODE (base2
) != TARGET_MEM_REF
1401 || (!TMR_INDEX (base2
) && !TMR_INDEX2 (base2
))))
1402 || (TREE_CODE (base1
) == TARGET_MEM_REF
1403 && TREE_CODE (base2
) == TARGET_MEM_REF
1404 && (TMR_STEP (base1
) == TMR_STEP (base2
)
1405 || (TMR_STEP (base1
) && TMR_STEP (base2
)
1406 && operand_equal_p (TMR_STEP (base1
),
1407 TMR_STEP (base2
), 0)))
1408 && (TMR_INDEX (base1
) == TMR_INDEX (base2
)
1409 || (TMR_INDEX (base1
) && TMR_INDEX (base2
)
1410 && operand_equal_p (TMR_INDEX (base1
),
1411 TMR_INDEX (base2
), 0)))
1412 && (TMR_INDEX2 (base1
) == TMR_INDEX2 (base2
)
1413 || (TMR_INDEX2 (base1
) && TMR_INDEX2 (base2
)
1414 && operand_equal_p (TMR_INDEX2 (base1
),
1415 TMR_INDEX2 (base2
), 0))))))
1417 poly_offset_int moff1
= mem_ref_offset (base1
) << LOG2_BITS_PER_UNIT
;
1418 poly_offset_int moff2
= mem_ref_offset (base2
) << LOG2_BITS_PER_UNIT
;
1419 return ranges_maybe_overlap_p (offset1
+ moff1
, max_size1
,
1420 offset2
+ moff2
, max_size2
);
1422 if (!ptr_derefs_may_alias_p (ptr1
, ptr2
))
1425 /* Disambiguations that rely on strict aliasing rules follow. */
1426 if (!flag_strict_aliasing
|| !tbaa_p
)
1429 ptrtype1
= TREE_TYPE (TREE_OPERAND (base1
, 1));
1430 ptrtype2
= TREE_TYPE (TREE_OPERAND (base2
, 1));
1432 /* If the alias set for a pointer access is zero all bets are off. */
1433 if (base1_alias_set
== 0
1434 || base2_alias_set
== 0)
1437 /* If both references are through the same type, they do not alias
1438 if the accesses do not overlap. This does extra disambiguation
1439 for mixed/pointer accesses but requires strict aliasing. */
1440 if ((TREE_CODE (base1
) != TARGET_MEM_REF
1441 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1442 && (TREE_CODE (base2
) != TARGET_MEM_REF
1443 || (!TMR_INDEX (base2
) && !TMR_INDEX2 (base2
)))
1444 && same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (ptrtype1
)) == 1
1445 && same_type_for_tbaa (TREE_TYPE (base2
), TREE_TYPE (ptrtype2
)) == 1
1446 && same_type_for_tbaa (TREE_TYPE (ptrtype1
),
1447 TREE_TYPE (ptrtype2
)) == 1
1448 /* But avoid treating arrays as "objects", instead assume they
1449 can overlap by an exact multiple of their element size. */
1450 && TREE_CODE (TREE_TYPE (ptrtype1
)) != ARRAY_TYPE
)
1451 return ranges_maybe_overlap_p (offset1
, max_size1
, offset2
, max_size2
);
1453 /* Do type-based disambiguation. */
1454 if (base1_alias_set
!= base2_alias_set
1455 && !alias_sets_conflict_p (base1_alias_set
, base2_alias_set
))
1458 /* If either reference is view-converted, give up now. */
1459 if (same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (ptrtype1
)) != 1
1460 || same_type_for_tbaa (TREE_TYPE (base2
), TREE_TYPE (ptrtype2
)) != 1)
1464 && nonoverlapping_component_refs_p (ref1
, ref2
))
1467 /* Do access-path based disambiguation. */
1469 && (handled_component_p (ref1
) || handled_component_p (ref2
)))
1470 return aliasing_component_refs_p (ref1
,
1471 ref1_alias_set
, base1_alias_set
,
1474 ref2_alias_set
, base2_alias_set
,
1475 offset2
, max_size2
, false);
1480 /* Return true, if the two memory references REF1 and REF2 may alias. */
1483 refs_may_alias_p_2 (ao_ref
*ref1
, ao_ref
*ref2
, bool tbaa_p
)
1486 poly_int64 offset1
= 0, offset2
= 0;
1487 poly_int64 max_size1
= -1, max_size2
= -1;
1488 bool var1_p
, var2_p
, ind1_p
, ind2_p
;
1490 gcc_checking_assert ((!ref1
->ref
1491 || TREE_CODE (ref1
->ref
) == SSA_NAME
1492 || DECL_P (ref1
->ref
)
1493 || TREE_CODE (ref1
->ref
) == STRING_CST
1494 || handled_component_p (ref1
->ref
)
1495 || TREE_CODE (ref1
->ref
) == MEM_REF
1496 || TREE_CODE (ref1
->ref
) == TARGET_MEM_REF
)
1498 || TREE_CODE (ref2
->ref
) == SSA_NAME
1499 || DECL_P (ref2
->ref
)
1500 || TREE_CODE (ref2
->ref
) == STRING_CST
1501 || handled_component_p (ref2
->ref
)
1502 || TREE_CODE (ref2
->ref
) == MEM_REF
1503 || TREE_CODE (ref2
->ref
) == TARGET_MEM_REF
));
1505 /* Decompose the references into their base objects and the access. */
1506 base1
= ao_ref_base (ref1
);
1507 offset1
= ref1
->offset
;
1508 max_size1
= ref1
->max_size
;
1509 base2
= ao_ref_base (ref2
);
1510 offset2
= ref2
->offset
;
1511 max_size2
= ref2
->max_size
;
1513 /* We can end up with registers or constants as bases for example from
1514 *D.1663_44 = VIEW_CONVERT_EXPR<struct DB_LSN>(__tmp$B0F64_59);
1515 which is seen as a struct copy. */
1516 if (TREE_CODE (base1
) == SSA_NAME
1517 || TREE_CODE (base1
) == CONST_DECL
1518 || TREE_CODE (base1
) == CONSTRUCTOR
1519 || TREE_CODE (base1
) == ADDR_EXPR
1520 || CONSTANT_CLASS_P (base1
)
1521 || TREE_CODE (base2
) == SSA_NAME
1522 || TREE_CODE (base2
) == CONST_DECL
1523 || TREE_CODE (base2
) == CONSTRUCTOR
1524 || TREE_CODE (base2
) == ADDR_EXPR
1525 || CONSTANT_CLASS_P (base2
))
1528 /* We can end up referring to code via function and label decls.
1529 As we likely do not properly track code aliases conservatively
1531 if (TREE_CODE (base1
) == FUNCTION_DECL
1532 || TREE_CODE (base1
) == LABEL_DECL
1533 || TREE_CODE (base2
) == FUNCTION_DECL
1534 || TREE_CODE (base2
) == LABEL_DECL
)
1537 /* Two volatile accesses always conflict. */
1538 if (ref1
->volatile_p
1539 && ref2
->volatile_p
)
1542 /* Defer to simple offset based disambiguation if we have
1543 references based on two decls. Do this before defering to
1544 TBAA to handle must-alias cases in conformance with the
1545 GCC extension of allowing type-punning through unions. */
1546 var1_p
= DECL_P (base1
);
1547 var2_p
= DECL_P (base2
);
1548 if (var1_p
&& var2_p
)
1549 return decl_refs_may_alias_p (ref1
->ref
, base1
, offset1
, max_size1
,
1550 ref2
->ref
, base2
, offset2
, max_size2
);
1552 /* Handle restrict based accesses.
1553 ??? ao_ref_base strips inner MEM_REF [&decl], recover from that
1555 tree rbase1
= base1
;
1556 tree rbase2
= base2
;
1561 while (handled_component_p (rbase1
))
1562 rbase1
= TREE_OPERAND (rbase1
, 0);
1568 while (handled_component_p (rbase2
))
1569 rbase2
= TREE_OPERAND (rbase2
, 0);
1571 if (rbase1
&& rbase2
1572 && (TREE_CODE (base1
) == MEM_REF
|| TREE_CODE (base1
) == TARGET_MEM_REF
)
1573 && (TREE_CODE (base2
) == MEM_REF
|| TREE_CODE (base2
) == TARGET_MEM_REF
)
1574 /* If the accesses are in the same restrict clique... */
1575 && MR_DEPENDENCE_CLIQUE (base1
) == MR_DEPENDENCE_CLIQUE (base2
)
1576 /* But based on different pointers they do not alias. */
1577 && MR_DEPENDENCE_BASE (base1
) != MR_DEPENDENCE_BASE (base2
))
1580 ind1_p
= (TREE_CODE (base1
) == MEM_REF
1581 || TREE_CODE (base1
) == TARGET_MEM_REF
);
1582 ind2_p
= (TREE_CODE (base2
) == MEM_REF
1583 || TREE_CODE (base2
) == TARGET_MEM_REF
);
1585 /* Canonicalize the pointer-vs-decl case. */
1586 if (ind1_p
&& var2_p
)
1588 std::swap (offset1
, offset2
);
1589 std::swap (max_size1
, max_size2
);
1590 std::swap (base1
, base2
);
1591 std::swap (ref1
, ref2
);
1598 /* First defer to TBAA if possible. */
1600 && flag_strict_aliasing
1601 && !alias_sets_conflict_p (ao_ref_alias_set (ref1
),
1602 ao_ref_alias_set (ref2
)))
1605 /* If the reference is based on a pointer that points to memory
1606 that may not be written to then the other reference cannot possibly
1608 if ((TREE_CODE (TREE_OPERAND (base2
, 0)) == SSA_NAME
1609 && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base2
, 0)))
1611 && TREE_CODE (TREE_OPERAND (base1
, 0)) == SSA_NAME
1612 && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base1
, 0))))
1615 /* Dispatch to the pointer-vs-decl or pointer-vs-pointer disambiguators. */
1616 if (var1_p
&& ind2_p
)
1617 return indirect_ref_may_alias_decl_p (ref2
->ref
, base2
,
1619 ao_ref_alias_set (ref2
),
1620 ao_ref_base_alias_set (ref2
),
1623 ao_ref_alias_set (ref1
),
1624 ao_ref_base_alias_set (ref1
),
1626 else if (ind1_p
&& ind2_p
)
1627 return indirect_refs_may_alias_p (ref1
->ref
, base1
,
1629 ao_ref_alias_set (ref1
),
1630 ao_ref_base_alias_set (ref1
),
1633 ao_ref_alias_set (ref2
),
1634 ao_ref_base_alias_set (ref2
),
1640 /* Return true, if the two memory references REF1 and REF2 may alias
1641 and update statistics. */
1644 refs_may_alias_p_1 (ao_ref
*ref1
, ao_ref
*ref2
, bool tbaa_p
)
1646 bool res
= refs_may_alias_p_2 (ref1
, ref2
, tbaa_p
);
1648 ++alias_stats
.refs_may_alias_p_may_alias
;
1650 ++alias_stats
.refs_may_alias_p_no_alias
;
1655 refs_may_alias_p (tree ref1
, ao_ref
*ref2
, bool tbaa_p
)
1658 ao_ref_init (&r1
, ref1
);
1659 return refs_may_alias_p_1 (&r1
, ref2
, tbaa_p
);
1663 refs_may_alias_p (tree ref1
, tree ref2
, bool tbaa_p
)
1666 ao_ref_init (&r1
, ref1
);
1667 ao_ref_init (&r2
, ref2
);
1668 return refs_may_alias_p_1 (&r1
, &r2
, tbaa_p
);
1671 /* Returns true if there is a anti-dependence for the STORE that
1672 executes after the LOAD. */
1675 refs_anti_dependent_p (tree load
, tree store
)
1678 ao_ref_init (&r1
, load
);
1679 ao_ref_init (&r2
, store
);
1680 return refs_may_alias_p_1 (&r1
, &r2
, false);
1683 /* Returns true if there is a output dependence for the stores
1684 STORE1 and STORE2. */
1687 refs_output_dependent_p (tree store1
, tree store2
)
1690 ao_ref_init (&r1
, store1
);
1691 ao_ref_init (&r2
, store2
);
1692 return refs_may_alias_p_1 (&r1
, &r2
, false);
1695 /* If the call CALL may use the memory reference REF return true,
1696 otherwise return false. */
1699 ref_maybe_used_by_call_p_1 (gcall
*call
, ao_ref
*ref
, bool tbaa_p
)
1703 int flags
= gimple_call_flags (call
);
1705 /* Const functions without a static chain do not implicitly use memory. */
1706 if (!gimple_call_chain (call
)
1707 && (flags
& (ECF_CONST
|ECF_NOVOPS
)))
1710 base
= ao_ref_base (ref
);
1714 /* A call that is not without side-effects might involve volatile
1715 accesses and thus conflicts with all other volatile accesses. */
1716 if (ref
->volatile_p
)
1719 /* If the reference is based on a decl that is not aliased the call
1720 cannot possibly use it. */
1722 && !may_be_aliased (base
)
1723 /* But local statics can be used through recursion. */
1724 && !is_global_var (base
))
1727 callee
= gimple_call_fndecl (call
);
1729 /* Handle those builtin functions explicitly that do not act as
1730 escape points. See tree-ssa-structalias.c:find_func_aliases
1731 for the list of builtins we might need to handle here. */
1732 if (callee
!= NULL_TREE
1733 && gimple_call_builtin_p (call
, BUILT_IN_NORMAL
))
1734 switch (DECL_FUNCTION_CODE (callee
))
1736 /* All the following functions read memory pointed to by
1737 their second argument. strcat/strncat additionally
1738 reads memory pointed to by the first argument. */
1739 case BUILT_IN_STRCAT
:
1740 case BUILT_IN_STRNCAT
:
1743 ao_ref_init_from_ptr_and_size (&dref
,
1744 gimple_call_arg (call
, 0),
1746 if (refs_may_alias_p_1 (&dref
, ref
, false))
1750 case BUILT_IN_STRCPY
:
1751 case BUILT_IN_STRNCPY
:
1752 case BUILT_IN_MEMCPY
:
1753 case BUILT_IN_MEMMOVE
:
1754 case BUILT_IN_MEMPCPY
:
1755 case BUILT_IN_STPCPY
:
1756 case BUILT_IN_STPNCPY
:
1757 case BUILT_IN_TM_MEMCPY
:
1758 case BUILT_IN_TM_MEMMOVE
:
1761 tree size
= NULL_TREE
;
1762 if (gimple_call_num_args (call
) == 3)
1763 size
= gimple_call_arg (call
, 2);
1764 ao_ref_init_from_ptr_and_size (&dref
,
1765 gimple_call_arg (call
, 1),
1767 return refs_may_alias_p_1 (&dref
, ref
, false);
1769 case BUILT_IN_STRCAT_CHK
:
1770 case BUILT_IN_STRNCAT_CHK
:
1773 ao_ref_init_from_ptr_and_size (&dref
,
1774 gimple_call_arg (call
, 0),
1776 if (refs_may_alias_p_1 (&dref
, ref
, false))
1780 case BUILT_IN_STRCPY_CHK
:
1781 case BUILT_IN_STRNCPY_CHK
:
1782 case BUILT_IN_MEMCPY_CHK
:
1783 case BUILT_IN_MEMMOVE_CHK
:
1784 case BUILT_IN_MEMPCPY_CHK
:
1785 case BUILT_IN_STPCPY_CHK
:
1786 case BUILT_IN_STPNCPY_CHK
:
1789 tree size
= NULL_TREE
;
1790 if (gimple_call_num_args (call
) == 4)
1791 size
= gimple_call_arg (call
, 2);
1792 ao_ref_init_from_ptr_and_size (&dref
,
1793 gimple_call_arg (call
, 1),
1795 return refs_may_alias_p_1 (&dref
, ref
, false);
1797 case BUILT_IN_BCOPY
:
1800 tree size
= gimple_call_arg (call
, 2);
1801 ao_ref_init_from_ptr_and_size (&dref
,
1802 gimple_call_arg (call
, 0),
1804 return refs_may_alias_p_1 (&dref
, ref
, false);
1807 /* The following functions read memory pointed to by their
1809 CASE_BUILT_IN_TM_LOAD (1):
1810 CASE_BUILT_IN_TM_LOAD (2):
1811 CASE_BUILT_IN_TM_LOAD (4):
1812 CASE_BUILT_IN_TM_LOAD (8):
1813 CASE_BUILT_IN_TM_LOAD (FLOAT
):
1814 CASE_BUILT_IN_TM_LOAD (DOUBLE
):
1815 CASE_BUILT_IN_TM_LOAD (LDOUBLE
):
1816 CASE_BUILT_IN_TM_LOAD (M64
):
1817 CASE_BUILT_IN_TM_LOAD (M128
):
1818 CASE_BUILT_IN_TM_LOAD (M256
):
1819 case BUILT_IN_TM_LOG
:
1820 case BUILT_IN_TM_LOG_1
:
1821 case BUILT_IN_TM_LOG_2
:
1822 case BUILT_IN_TM_LOG_4
:
1823 case BUILT_IN_TM_LOG_8
:
1824 case BUILT_IN_TM_LOG_FLOAT
:
1825 case BUILT_IN_TM_LOG_DOUBLE
:
1826 case BUILT_IN_TM_LOG_LDOUBLE
:
1827 case BUILT_IN_TM_LOG_M64
:
1828 case BUILT_IN_TM_LOG_M128
:
1829 case BUILT_IN_TM_LOG_M256
:
1830 return ptr_deref_may_alias_ref_p_1 (gimple_call_arg (call
, 0), ref
);
1832 /* These read memory pointed to by the first argument. */
1833 case BUILT_IN_STRDUP
:
1834 case BUILT_IN_STRNDUP
:
1835 case BUILT_IN_REALLOC
:
1838 tree size
= NULL_TREE
;
1839 if (gimple_call_num_args (call
) == 2)
1840 size
= gimple_call_arg (call
, 1);
1841 ao_ref_init_from_ptr_and_size (&dref
,
1842 gimple_call_arg (call
, 0),
1844 return refs_may_alias_p_1 (&dref
, ref
, false);
1846 /* These read memory pointed to by the first argument. */
1847 case BUILT_IN_INDEX
:
1848 case BUILT_IN_STRCHR
:
1849 case BUILT_IN_STRRCHR
:
1852 ao_ref_init_from_ptr_and_size (&dref
,
1853 gimple_call_arg (call
, 0),
1855 return refs_may_alias_p_1 (&dref
, ref
, false);
1857 /* These read memory pointed to by the first argument with size
1858 in the third argument. */
1859 case BUILT_IN_MEMCHR
:
1862 ao_ref_init_from_ptr_and_size (&dref
,
1863 gimple_call_arg (call
, 0),
1864 gimple_call_arg (call
, 2));
1865 return refs_may_alias_p_1 (&dref
, ref
, false);
1867 /* These read memory pointed to by the first and second arguments. */
1868 case BUILT_IN_STRSTR
:
1869 case BUILT_IN_STRPBRK
:
1872 ao_ref_init_from_ptr_and_size (&dref
,
1873 gimple_call_arg (call
, 0),
1875 if (refs_may_alias_p_1 (&dref
, ref
, false))
1877 ao_ref_init_from_ptr_and_size (&dref
,
1878 gimple_call_arg (call
, 1),
1880 return refs_may_alias_p_1 (&dref
, ref
, false);
1883 /* The following builtins do not read from memory. */
1885 case BUILT_IN_MALLOC
:
1886 case BUILT_IN_POSIX_MEMALIGN
:
1887 case BUILT_IN_ALIGNED_ALLOC
:
1888 case BUILT_IN_CALLOC
:
1889 CASE_BUILT_IN_ALLOCA
:
1890 case BUILT_IN_STACK_SAVE
:
1891 case BUILT_IN_STACK_RESTORE
:
1892 case BUILT_IN_MEMSET
:
1893 case BUILT_IN_TM_MEMSET
:
1894 case BUILT_IN_MEMSET_CHK
:
1895 case BUILT_IN_FREXP
:
1896 case BUILT_IN_FREXPF
:
1897 case BUILT_IN_FREXPL
:
1898 case BUILT_IN_GAMMA_R
:
1899 case BUILT_IN_GAMMAF_R
:
1900 case BUILT_IN_GAMMAL_R
:
1901 case BUILT_IN_LGAMMA_R
:
1902 case BUILT_IN_LGAMMAF_R
:
1903 case BUILT_IN_LGAMMAL_R
:
1905 case BUILT_IN_MODFF
:
1906 case BUILT_IN_MODFL
:
1907 case BUILT_IN_REMQUO
:
1908 case BUILT_IN_REMQUOF
:
1909 case BUILT_IN_REMQUOL
:
1910 case BUILT_IN_SINCOS
:
1911 case BUILT_IN_SINCOSF
:
1912 case BUILT_IN_SINCOSL
:
1913 case BUILT_IN_ASSUME_ALIGNED
:
1914 case BUILT_IN_VA_END
:
1916 /* __sync_* builtins and some OpenMP builtins act as threading
1918 #undef DEF_SYNC_BUILTIN
1919 #define DEF_SYNC_BUILTIN(ENUM, NAME, TYPE, ATTRS) case ENUM:
1920 #include "sync-builtins.def"
1921 #undef DEF_SYNC_BUILTIN
1922 case BUILT_IN_GOMP_ATOMIC_START
:
1923 case BUILT_IN_GOMP_ATOMIC_END
:
1924 case BUILT_IN_GOMP_BARRIER
:
1925 case BUILT_IN_GOMP_BARRIER_CANCEL
:
1926 case BUILT_IN_GOMP_TASKWAIT
:
1927 case BUILT_IN_GOMP_TASKGROUP_END
:
1928 case BUILT_IN_GOMP_CRITICAL_START
:
1929 case BUILT_IN_GOMP_CRITICAL_END
:
1930 case BUILT_IN_GOMP_CRITICAL_NAME_START
:
1931 case BUILT_IN_GOMP_CRITICAL_NAME_END
:
1932 case BUILT_IN_GOMP_LOOP_END
:
1933 case BUILT_IN_GOMP_LOOP_END_CANCEL
:
1934 case BUILT_IN_GOMP_ORDERED_START
:
1935 case BUILT_IN_GOMP_ORDERED_END
:
1936 case BUILT_IN_GOMP_SECTIONS_END
:
1937 case BUILT_IN_GOMP_SECTIONS_END_CANCEL
:
1938 case BUILT_IN_GOMP_SINGLE_COPY_START
:
1939 case BUILT_IN_GOMP_SINGLE_COPY_END
:
1943 /* Fallthru to general call handling. */;
1946 /* Check if base is a global static variable that is not read
1948 if (callee
!= NULL_TREE
&& VAR_P (base
) && TREE_STATIC (base
))
1950 struct cgraph_node
*node
= cgraph_node::get (callee
);
1953 /* FIXME: Callee can be an OMP builtin that does not have a call graph
1954 node yet. We should enforce that there are nodes for all decls in the
1955 IL and remove this check instead. */
1957 && (not_read
= ipa_reference_get_not_read_global (node
))
1958 && bitmap_bit_p (not_read
, ipa_reference_var_uid (base
)))
1962 /* Check if the base variable is call-used. */
1965 if (pt_solution_includes (gimple_call_use_set (call
), base
))
1968 else if ((TREE_CODE (base
) == MEM_REF
1969 || TREE_CODE (base
) == TARGET_MEM_REF
)
1970 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
)
1972 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (TREE_OPERAND (base
, 0));
1976 if (pt_solutions_intersect (gimple_call_use_set (call
), &pi
->pt
))
1982 /* Inspect call arguments for passed-by-value aliases. */
1984 for (i
= 0; i
< gimple_call_num_args (call
); ++i
)
1986 tree op
= gimple_call_arg (call
, i
);
1987 int flags
= gimple_call_arg_flags (call
, i
);
1989 if (flags
& EAF_UNUSED
)
1992 if (TREE_CODE (op
) == WITH_SIZE_EXPR
)
1993 op
= TREE_OPERAND (op
, 0);
1995 if (TREE_CODE (op
) != SSA_NAME
1996 && !is_gimple_min_invariant (op
))
1999 ao_ref_init (&r
, op
);
2000 if (refs_may_alias_p_1 (&r
, ref
, tbaa_p
))
2009 ref_maybe_used_by_call_p (gcall
*call
, ao_ref
*ref
, bool tbaa_p
)
2012 res
= ref_maybe_used_by_call_p_1 (call
, ref
, tbaa_p
);
2014 ++alias_stats
.ref_maybe_used_by_call_p_may_alias
;
2016 ++alias_stats
.ref_maybe_used_by_call_p_no_alias
;
2021 /* If the statement STMT may use the memory reference REF return
2022 true, otherwise return false. */
2025 ref_maybe_used_by_stmt_p (gimple
*stmt
, ao_ref
*ref
, bool tbaa_p
)
2027 if (is_gimple_assign (stmt
))
2031 /* All memory assign statements are single. */
2032 if (!gimple_assign_single_p (stmt
))
2035 rhs
= gimple_assign_rhs1 (stmt
);
2036 if (is_gimple_reg (rhs
)
2037 || is_gimple_min_invariant (rhs
)
2038 || gimple_assign_rhs_code (stmt
) == CONSTRUCTOR
)
2041 return refs_may_alias_p (rhs
, ref
, tbaa_p
);
2043 else if (is_gimple_call (stmt
))
2044 return ref_maybe_used_by_call_p (as_a
<gcall
*> (stmt
), ref
, tbaa_p
);
2045 else if (greturn
*return_stmt
= dyn_cast
<greturn
*> (stmt
))
2047 tree retval
= gimple_return_retval (return_stmt
);
2049 && TREE_CODE (retval
) != SSA_NAME
2050 && !is_gimple_min_invariant (retval
)
2051 && refs_may_alias_p (retval
, ref
, tbaa_p
))
2053 /* If ref escapes the function then the return acts as a use. */
2054 tree base
= ao_ref_base (ref
);
2057 else if (DECL_P (base
))
2058 return is_global_var (base
);
2059 else if (TREE_CODE (base
) == MEM_REF
2060 || TREE_CODE (base
) == TARGET_MEM_REF
)
2061 return ptr_deref_may_alias_global_p (TREE_OPERAND (base
, 0));
2069 ref_maybe_used_by_stmt_p (gimple
*stmt
, tree ref
, bool tbaa_p
)
2072 ao_ref_init (&r
, ref
);
2073 return ref_maybe_used_by_stmt_p (stmt
, &r
, tbaa_p
);
2076 /* If the call in statement CALL may clobber the memory reference REF
2077 return true, otherwise return false. */
2080 call_may_clobber_ref_p_1 (gcall
*call
, ao_ref
*ref
)
2085 /* If the call is pure or const it cannot clobber anything. */
2086 if (gimple_call_flags (call
)
2087 & (ECF_PURE
|ECF_CONST
|ECF_LOOPING_CONST_OR_PURE
|ECF_NOVOPS
))
2089 if (gimple_call_internal_p (call
))
2090 switch (gimple_call_internal_fn (call
))
2092 /* Treat these internal calls like ECF_PURE for aliasing,
2093 they don't write to any memory the program should care about.
2094 They have important other side-effects, and read memory,
2095 so can't be ECF_NOVOPS. */
2096 case IFN_UBSAN_NULL
:
2097 case IFN_UBSAN_BOUNDS
:
2098 case IFN_UBSAN_VPTR
:
2099 case IFN_UBSAN_OBJECT_SIZE
:
2101 case IFN_ASAN_CHECK
:
2107 base
= ao_ref_base (ref
);
2111 if (TREE_CODE (base
) == SSA_NAME
2112 || CONSTANT_CLASS_P (base
))
2115 /* A call that is not without side-effects might involve volatile
2116 accesses and thus conflicts with all other volatile accesses. */
2117 if (ref
->volatile_p
)
2120 /* If the reference is based on a decl that is not aliased the call
2121 cannot possibly clobber it. */
2123 && !may_be_aliased (base
)
2124 /* But local non-readonly statics can be modified through recursion
2125 or the call may implement a threading barrier which we must
2126 treat as may-def. */
2127 && (TREE_READONLY (base
)
2128 || !is_global_var (base
)))
2131 /* If the reference is based on a pointer that points to memory
2132 that may not be written to then the call cannot possibly clobber it. */
2133 if ((TREE_CODE (base
) == MEM_REF
2134 || TREE_CODE (base
) == TARGET_MEM_REF
)
2135 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
2136 && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base
, 0)))
2139 callee
= gimple_call_fndecl (call
);
2141 /* Handle those builtin functions explicitly that do not act as
2142 escape points. See tree-ssa-structalias.c:find_func_aliases
2143 for the list of builtins we might need to handle here. */
2144 if (callee
!= NULL_TREE
2145 && gimple_call_builtin_p (call
, BUILT_IN_NORMAL
))
2146 switch (DECL_FUNCTION_CODE (callee
))
2148 /* All the following functions clobber memory pointed to by
2149 their first argument. */
2150 case BUILT_IN_STRCPY
:
2151 case BUILT_IN_STRNCPY
:
2152 case BUILT_IN_MEMCPY
:
2153 case BUILT_IN_MEMMOVE
:
2154 case BUILT_IN_MEMPCPY
:
2155 case BUILT_IN_STPCPY
:
2156 case BUILT_IN_STPNCPY
:
2157 case BUILT_IN_STRCAT
:
2158 case BUILT_IN_STRNCAT
:
2159 case BUILT_IN_MEMSET
:
2160 case BUILT_IN_TM_MEMSET
:
2161 CASE_BUILT_IN_TM_STORE (1):
2162 CASE_BUILT_IN_TM_STORE (2):
2163 CASE_BUILT_IN_TM_STORE (4):
2164 CASE_BUILT_IN_TM_STORE (8):
2165 CASE_BUILT_IN_TM_STORE (FLOAT
):
2166 CASE_BUILT_IN_TM_STORE (DOUBLE
):
2167 CASE_BUILT_IN_TM_STORE (LDOUBLE
):
2168 CASE_BUILT_IN_TM_STORE (M64
):
2169 CASE_BUILT_IN_TM_STORE (M128
):
2170 CASE_BUILT_IN_TM_STORE (M256
):
2171 case BUILT_IN_TM_MEMCPY
:
2172 case BUILT_IN_TM_MEMMOVE
:
2175 tree size
= NULL_TREE
;
2176 /* Don't pass in size for strncat, as the maximum size
2177 is strlen (dest) + n + 1 instead of n, resp.
2178 n + 1 at dest + strlen (dest), but strlen (dest) isn't
2180 if (gimple_call_num_args (call
) == 3
2181 && DECL_FUNCTION_CODE (callee
) != BUILT_IN_STRNCAT
)
2182 size
= gimple_call_arg (call
, 2);
2183 ao_ref_init_from_ptr_and_size (&dref
,
2184 gimple_call_arg (call
, 0),
2186 return refs_may_alias_p_1 (&dref
, ref
, false);
2188 case BUILT_IN_STRCPY_CHK
:
2189 case BUILT_IN_STRNCPY_CHK
:
2190 case BUILT_IN_MEMCPY_CHK
:
2191 case BUILT_IN_MEMMOVE_CHK
:
2192 case BUILT_IN_MEMPCPY_CHK
:
2193 case BUILT_IN_STPCPY_CHK
:
2194 case BUILT_IN_STPNCPY_CHK
:
2195 case BUILT_IN_STRCAT_CHK
:
2196 case BUILT_IN_STRNCAT_CHK
:
2197 case BUILT_IN_MEMSET_CHK
:
2200 tree size
= NULL_TREE
;
2201 /* Don't pass in size for __strncat_chk, as the maximum size
2202 is strlen (dest) + n + 1 instead of n, resp.
2203 n + 1 at dest + strlen (dest), but strlen (dest) isn't
2205 if (gimple_call_num_args (call
) == 4
2206 && DECL_FUNCTION_CODE (callee
) != BUILT_IN_STRNCAT_CHK
)
2207 size
= gimple_call_arg (call
, 2);
2208 ao_ref_init_from_ptr_and_size (&dref
,
2209 gimple_call_arg (call
, 0),
2211 return refs_may_alias_p_1 (&dref
, ref
, false);
2213 case BUILT_IN_BCOPY
:
2216 tree size
= gimple_call_arg (call
, 2);
2217 ao_ref_init_from_ptr_and_size (&dref
,
2218 gimple_call_arg (call
, 1),
2220 return refs_may_alias_p_1 (&dref
, ref
, false);
2222 /* Allocating memory does not have any side-effects apart from
2223 being the definition point for the pointer. */
2224 case BUILT_IN_MALLOC
:
2225 case BUILT_IN_ALIGNED_ALLOC
:
2226 case BUILT_IN_CALLOC
:
2227 case BUILT_IN_STRDUP
:
2228 case BUILT_IN_STRNDUP
:
2229 /* Unix98 specifies that errno is set on allocation failure. */
2231 && targetm
.ref_may_alias_errno (ref
))
2234 case BUILT_IN_STACK_SAVE
:
2235 CASE_BUILT_IN_ALLOCA
:
2236 case BUILT_IN_ASSUME_ALIGNED
:
2238 /* But posix_memalign stores a pointer into the memory pointed to
2239 by its first argument. */
2240 case BUILT_IN_POSIX_MEMALIGN
:
2242 tree ptrptr
= gimple_call_arg (call
, 0);
2244 ao_ref_init_from_ptr_and_size (&dref
, ptrptr
,
2245 TYPE_SIZE_UNIT (ptr_type_node
));
2246 return (refs_may_alias_p_1 (&dref
, ref
, false)
2248 && targetm
.ref_may_alias_errno (ref
)));
2250 /* Freeing memory kills the pointed-to memory. More importantly
2251 the call has to serve as a barrier for moving loads and stores
2254 case BUILT_IN_VA_END
:
2256 tree ptr
= gimple_call_arg (call
, 0);
2257 return ptr_deref_may_alias_ref_p_1 (ptr
, ref
);
2259 /* Realloc serves both as allocation point and deallocation point. */
2260 case BUILT_IN_REALLOC
:
2262 tree ptr
= gimple_call_arg (call
, 0);
2263 /* Unix98 specifies that errno is set on allocation failure. */
2264 return ((flag_errno_math
2265 && targetm
.ref_may_alias_errno (ref
))
2266 || ptr_deref_may_alias_ref_p_1 (ptr
, ref
));
2268 case BUILT_IN_GAMMA_R
:
2269 case BUILT_IN_GAMMAF_R
:
2270 case BUILT_IN_GAMMAL_R
:
2271 case BUILT_IN_LGAMMA_R
:
2272 case BUILT_IN_LGAMMAF_R
:
2273 case BUILT_IN_LGAMMAL_R
:
2275 tree out
= gimple_call_arg (call
, 1);
2276 if (ptr_deref_may_alias_ref_p_1 (out
, ref
))
2278 if (flag_errno_math
)
2282 case BUILT_IN_FREXP
:
2283 case BUILT_IN_FREXPF
:
2284 case BUILT_IN_FREXPL
:
2286 case BUILT_IN_MODFF
:
2287 case BUILT_IN_MODFL
:
2289 tree out
= gimple_call_arg (call
, 1);
2290 return ptr_deref_may_alias_ref_p_1 (out
, ref
);
2292 case BUILT_IN_REMQUO
:
2293 case BUILT_IN_REMQUOF
:
2294 case BUILT_IN_REMQUOL
:
2296 tree out
= gimple_call_arg (call
, 2);
2297 if (ptr_deref_may_alias_ref_p_1 (out
, ref
))
2299 if (flag_errno_math
)
2303 case BUILT_IN_SINCOS
:
2304 case BUILT_IN_SINCOSF
:
2305 case BUILT_IN_SINCOSL
:
2307 tree sin
= gimple_call_arg (call
, 1);
2308 tree cos
= gimple_call_arg (call
, 2);
2309 return (ptr_deref_may_alias_ref_p_1 (sin
, ref
)
2310 || ptr_deref_may_alias_ref_p_1 (cos
, ref
));
2312 /* __sync_* builtins and some OpenMP builtins act as threading
2314 #undef DEF_SYNC_BUILTIN
2315 #define DEF_SYNC_BUILTIN(ENUM, NAME, TYPE, ATTRS) case ENUM:
2316 #include "sync-builtins.def"
2317 #undef DEF_SYNC_BUILTIN
2318 case BUILT_IN_GOMP_ATOMIC_START
:
2319 case BUILT_IN_GOMP_ATOMIC_END
:
2320 case BUILT_IN_GOMP_BARRIER
:
2321 case BUILT_IN_GOMP_BARRIER_CANCEL
:
2322 case BUILT_IN_GOMP_TASKWAIT
:
2323 case BUILT_IN_GOMP_TASKGROUP_END
:
2324 case BUILT_IN_GOMP_CRITICAL_START
:
2325 case BUILT_IN_GOMP_CRITICAL_END
:
2326 case BUILT_IN_GOMP_CRITICAL_NAME_START
:
2327 case BUILT_IN_GOMP_CRITICAL_NAME_END
:
2328 case BUILT_IN_GOMP_LOOP_END
:
2329 case BUILT_IN_GOMP_LOOP_END_CANCEL
:
2330 case BUILT_IN_GOMP_ORDERED_START
:
2331 case BUILT_IN_GOMP_ORDERED_END
:
2332 case BUILT_IN_GOMP_SECTIONS_END
:
2333 case BUILT_IN_GOMP_SECTIONS_END_CANCEL
:
2334 case BUILT_IN_GOMP_SINGLE_COPY_START
:
2335 case BUILT_IN_GOMP_SINGLE_COPY_END
:
2338 /* Fallthru to general call handling. */;
2341 /* Check if base is a global static variable that is not written
2343 if (callee
!= NULL_TREE
&& VAR_P (base
) && TREE_STATIC (base
))
2345 struct cgraph_node
*node
= cgraph_node::get (callee
);
2349 && (not_written
= ipa_reference_get_not_written_global (node
))
2350 && bitmap_bit_p (not_written
, ipa_reference_var_uid (base
)))
2354 /* Check if the base variable is call-clobbered. */
2356 return pt_solution_includes (gimple_call_clobber_set (call
), base
);
2357 else if ((TREE_CODE (base
) == MEM_REF
2358 || TREE_CODE (base
) == TARGET_MEM_REF
)
2359 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
)
2361 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (TREE_OPERAND (base
, 0));
2365 return pt_solutions_intersect (gimple_call_clobber_set (call
), &pi
->pt
);
2371 /* If the call in statement CALL may clobber the memory reference REF
2372 return true, otherwise return false. */
2375 call_may_clobber_ref_p (gcall
*call
, tree ref
)
2379 ao_ref_init (&r
, ref
);
2380 res
= call_may_clobber_ref_p_1 (call
, &r
);
2382 ++alias_stats
.call_may_clobber_ref_p_may_alias
;
2384 ++alias_stats
.call_may_clobber_ref_p_no_alias
;
2389 /* If the statement STMT may clobber the memory reference REF return true,
2390 otherwise return false. */
2393 stmt_may_clobber_ref_p_1 (gimple
*stmt
, ao_ref
*ref
, bool tbaa_p
)
2395 if (is_gimple_call (stmt
))
2397 tree lhs
= gimple_call_lhs (stmt
);
2399 && TREE_CODE (lhs
) != SSA_NAME
)
2402 ao_ref_init (&r
, lhs
);
2403 if (refs_may_alias_p_1 (ref
, &r
, tbaa_p
))
2407 return call_may_clobber_ref_p_1 (as_a
<gcall
*> (stmt
), ref
);
2409 else if (gimple_assign_single_p (stmt
))
2411 tree lhs
= gimple_assign_lhs (stmt
);
2412 if (TREE_CODE (lhs
) != SSA_NAME
)
2415 ao_ref_init (&r
, lhs
);
2416 return refs_may_alias_p_1 (ref
, &r
, tbaa_p
);
2419 else if (gimple_code (stmt
) == GIMPLE_ASM
)
2426 stmt_may_clobber_ref_p (gimple
*stmt
, tree ref
, bool tbaa_p
)
2429 ao_ref_init (&r
, ref
);
2430 return stmt_may_clobber_ref_p_1 (stmt
, &r
, tbaa_p
);
2433 /* Return true if store1 and store2 described by corresponding tuples
2434 <BASE, OFFSET, SIZE, MAX_SIZE> have the same size and store to the same
2438 same_addr_size_stores_p (tree base1
, poly_int64 offset1
, poly_int64 size1
,
2439 poly_int64 max_size1
,
2440 tree base2
, poly_int64 offset2
, poly_int64 size2
,
2441 poly_int64 max_size2
)
2443 /* Offsets need to be 0. */
2444 if (maybe_ne (offset1
, 0)
2445 || maybe_ne (offset2
, 0))
2448 bool base1_obj_p
= SSA_VAR_P (base1
);
2449 bool base2_obj_p
= SSA_VAR_P (base2
);
2451 /* We need one object. */
2452 if (base1_obj_p
== base2_obj_p
)
2454 tree obj
= base1_obj_p
? base1
: base2
;
2456 /* And we need one MEM_REF. */
2457 bool base1_memref_p
= TREE_CODE (base1
) == MEM_REF
;
2458 bool base2_memref_p
= TREE_CODE (base2
) == MEM_REF
;
2459 if (base1_memref_p
== base2_memref_p
)
2461 tree memref
= base1_memref_p
? base1
: base2
;
2463 /* Sizes need to be valid. */
2464 if (!known_size_p (max_size1
)
2465 || !known_size_p (max_size2
)
2466 || !known_size_p (size1
)
2467 || !known_size_p (size2
))
2470 /* Max_size needs to match size. */
2471 if (maybe_ne (max_size1
, size1
)
2472 || maybe_ne (max_size2
, size2
))
2475 /* Sizes need to match. */
2476 if (maybe_ne (size1
, size2
))
2480 /* Check that memref is a store to pointer with singleton points-to info. */
2481 if (!integer_zerop (TREE_OPERAND (memref
, 1)))
2483 tree ptr
= TREE_OPERAND (memref
, 0);
2484 if (TREE_CODE (ptr
) != SSA_NAME
)
2486 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (ptr
);
2487 unsigned int pt_uid
;
2489 || !pt_solution_singleton_or_null_p (&pi
->pt
, &pt_uid
))
2492 /* Be conservative with non-call exceptions when the address might
2494 if (cfun
->can_throw_non_call_exceptions
&& pi
->pt
.null
)
2497 /* Check that ptr points relative to obj. */
2498 unsigned int obj_uid
= DECL_PT_UID (obj
);
2499 if (obj_uid
!= pt_uid
)
2502 /* Check that the object size is the same as the store size. That ensures us
2503 that ptr points to the start of obj. */
2504 return (DECL_SIZE (obj
)
2505 && poly_int_tree_p (DECL_SIZE (obj
))
2506 && known_eq (wi::to_poly_offset (DECL_SIZE (obj
)), size1
));
2509 /* If STMT kills the memory reference REF return true, otherwise
2513 stmt_kills_ref_p (gimple
*stmt
, ao_ref
*ref
)
2515 if (!ao_ref_base (ref
))
2518 if (gimple_has_lhs (stmt
)
2519 && TREE_CODE (gimple_get_lhs (stmt
)) != SSA_NAME
2520 /* The assignment is not necessarily carried out if it can throw
2521 and we can catch it in the current function where we could inspect
2523 ??? We only need to care about the RHS throwing. For aggregate
2524 assignments or similar calls and non-call exceptions the LHS
2525 might throw as well. */
2526 && !stmt_can_throw_internal (cfun
, stmt
))
2528 tree lhs
= gimple_get_lhs (stmt
);
2529 /* If LHS is literally a base of the access we are done. */
2532 tree base
= ref
->ref
;
2533 tree innermost_dropped_array_ref
= NULL_TREE
;
2534 if (handled_component_p (base
))
2536 tree saved_lhs0
= NULL_TREE
;
2537 if (handled_component_p (lhs
))
2539 saved_lhs0
= TREE_OPERAND (lhs
, 0);
2540 TREE_OPERAND (lhs
, 0) = integer_zero_node
;
2544 /* Just compare the outermost handled component, if
2545 they are equal we have found a possible common
2547 tree saved_base0
= TREE_OPERAND (base
, 0);
2548 TREE_OPERAND (base
, 0) = integer_zero_node
;
2549 bool res
= operand_equal_p (lhs
, base
, 0);
2550 TREE_OPERAND (base
, 0) = saved_base0
;
2553 /* Remember if we drop an array-ref that we need to
2554 double-check not being at struct end. */
2555 if (TREE_CODE (base
) == ARRAY_REF
2556 || TREE_CODE (base
) == ARRAY_RANGE_REF
)
2557 innermost_dropped_array_ref
= base
;
2558 /* Otherwise drop handled components of the access. */
2561 while (handled_component_p (base
));
2563 TREE_OPERAND (lhs
, 0) = saved_lhs0
;
2565 /* Finally check if the lhs has the same address and size as the
2566 base candidate of the access. Watch out if we have dropped
2567 an array-ref that was at struct end, this means ref->ref may
2568 be outside of the TYPE_SIZE of its base. */
2569 if ((! innermost_dropped_array_ref
2570 || ! array_at_struct_end_p (innermost_dropped_array_ref
))
2572 || (((TYPE_SIZE (TREE_TYPE (lhs
))
2573 == TYPE_SIZE (TREE_TYPE (base
)))
2574 || (TYPE_SIZE (TREE_TYPE (lhs
))
2575 && TYPE_SIZE (TREE_TYPE (base
))
2576 && operand_equal_p (TYPE_SIZE (TREE_TYPE (lhs
)),
2577 TYPE_SIZE (TREE_TYPE (base
)),
2579 && operand_equal_p (lhs
, base
,
2581 | OEP_MATCH_SIDE_EFFECTS
))))
2585 /* Now look for non-literal equal bases with the restriction of
2586 handling constant offset and size. */
2587 /* For a must-alias check we need to be able to constrain
2588 the access properly. */
2589 if (!ref
->max_size_known_p ())
2591 poly_int64 size
, offset
, max_size
, ref_offset
= ref
->offset
;
2593 tree base
= get_ref_base_and_extent (lhs
, &offset
, &size
, &max_size
,
2595 /* We can get MEM[symbol: sZ, index: D.8862_1] here,
2596 so base == ref->base does not always hold. */
2597 if (base
!= ref
->base
)
2599 /* Try using points-to info. */
2600 if (same_addr_size_stores_p (base
, offset
, size
, max_size
, ref
->base
,
2601 ref
->offset
, ref
->size
, ref
->max_size
))
2604 /* If both base and ref->base are MEM_REFs, only compare the
2605 first operand, and if the second operand isn't equal constant,
2606 try to add the offsets into offset and ref_offset. */
2607 if (TREE_CODE (base
) == MEM_REF
&& TREE_CODE (ref
->base
) == MEM_REF
2608 && TREE_OPERAND (base
, 0) == TREE_OPERAND (ref
->base
, 0))
2610 if (!tree_int_cst_equal (TREE_OPERAND (base
, 1),
2611 TREE_OPERAND (ref
->base
, 1)))
2613 poly_offset_int off1
= mem_ref_offset (base
);
2614 off1
<<= LOG2_BITS_PER_UNIT
;
2616 poly_offset_int off2
= mem_ref_offset (ref
->base
);
2617 off2
<<= LOG2_BITS_PER_UNIT
;
2619 if (!off1
.to_shwi (&offset
) || !off2
.to_shwi (&ref_offset
))
2626 /* For a must-alias check we need to be able to constrain
2627 the access properly. */
2628 if (known_eq (size
, max_size
)
2629 && known_subrange_p (ref_offset
, ref
->max_size
, offset
, size
))
2633 if (is_gimple_call (stmt
))
2635 tree callee
= gimple_call_fndecl (stmt
);
2636 if (callee
!= NULL_TREE
2637 && gimple_call_builtin_p (stmt
, BUILT_IN_NORMAL
))
2638 switch (DECL_FUNCTION_CODE (callee
))
2642 tree ptr
= gimple_call_arg (stmt
, 0);
2643 tree base
= ao_ref_base (ref
);
2644 if (base
&& TREE_CODE (base
) == MEM_REF
2645 && TREE_OPERAND (base
, 0) == ptr
)
2650 case BUILT_IN_MEMCPY
:
2651 case BUILT_IN_MEMPCPY
:
2652 case BUILT_IN_MEMMOVE
:
2653 case BUILT_IN_MEMSET
:
2654 case BUILT_IN_MEMCPY_CHK
:
2655 case BUILT_IN_MEMPCPY_CHK
:
2656 case BUILT_IN_MEMMOVE_CHK
:
2657 case BUILT_IN_MEMSET_CHK
:
2658 case BUILT_IN_STRNCPY
:
2659 case BUILT_IN_STPNCPY
:
2661 /* For a must-alias check we need to be able to constrain
2662 the access properly. */
2663 if (!ref
->max_size_known_p ())
2665 tree dest
= gimple_call_arg (stmt
, 0);
2666 tree len
= gimple_call_arg (stmt
, 2);
2667 if (!poly_int_tree_p (len
))
2669 tree rbase
= ref
->base
;
2670 poly_offset_int roffset
= ref
->offset
;
2672 ao_ref_init_from_ptr_and_size (&dref
, dest
, len
);
2673 tree base
= ao_ref_base (&dref
);
2674 poly_offset_int offset
= dref
.offset
;
2675 if (!base
|| !known_size_p (dref
.size
))
2677 if (TREE_CODE (base
) == MEM_REF
)
2679 if (TREE_CODE (rbase
) != MEM_REF
)
2681 // Compare pointers.
2682 offset
+= mem_ref_offset (base
) << LOG2_BITS_PER_UNIT
;
2683 roffset
+= mem_ref_offset (rbase
) << LOG2_BITS_PER_UNIT
;
2684 base
= TREE_OPERAND (base
, 0);
2685 rbase
= TREE_OPERAND (rbase
, 0);
2688 && known_subrange_p (roffset
, ref
->max_size
, offset
,
2689 wi::to_poly_offset (len
)
2690 << LOG2_BITS_PER_UNIT
))
2695 case BUILT_IN_VA_END
:
2697 tree ptr
= gimple_call_arg (stmt
, 0);
2698 if (TREE_CODE (ptr
) == ADDR_EXPR
)
2700 tree base
= ao_ref_base (ref
);
2701 if (TREE_OPERAND (ptr
, 0) == base
)
2714 stmt_kills_ref_p (gimple
*stmt
, tree ref
)
2717 ao_ref_init (&r
, ref
);
2718 return stmt_kills_ref_p (stmt
, &r
);
2722 /* Walk the virtual use-def chain of VUSE until hitting the virtual operand
2723 TARGET or a statement clobbering the memory reference REF in which
2724 case false is returned. The walk starts with VUSE, one argument of PHI. */
2727 maybe_skip_until (gimple
*phi
, tree
&target
, basic_block target_bb
,
2728 ao_ref
*ref
, tree vuse
, unsigned int &limit
, bitmap
*visited
,
2729 bool abort_on_visited
,
2730 void *(*translate
)(ao_ref
*, tree
, void *, bool *),
2733 basic_block bb
= gimple_bb (phi
);
2736 *visited
= BITMAP_ALLOC (NULL
);
2738 bitmap_set_bit (*visited
, SSA_NAME_VERSION (PHI_RESULT (phi
)));
2740 /* Walk until we hit the target. */
2741 while (vuse
!= target
)
2743 gimple
*def_stmt
= SSA_NAME_DEF_STMT (vuse
);
2744 /* If we are searching for the target VUSE by walking up to
2745 TARGET_BB dominating the original PHI we are finished once
2746 we reach a default def or a definition in a block dominating
2747 that block. Update TARGET and return. */
2749 && (gimple_nop_p (def_stmt
)
2750 || dominated_by_p (CDI_DOMINATORS
,
2751 target_bb
, gimple_bb (def_stmt
))))
2757 /* Recurse for PHI nodes. */
2758 if (gimple_code (def_stmt
) == GIMPLE_PHI
)
2760 /* An already visited PHI node ends the walk successfully. */
2761 if (bitmap_bit_p (*visited
, SSA_NAME_VERSION (PHI_RESULT (def_stmt
))))
2762 return !abort_on_visited
;
2763 vuse
= get_continuation_for_phi (def_stmt
, ref
, limit
,
2764 visited
, abort_on_visited
,
2770 else if (gimple_nop_p (def_stmt
))
2774 /* A clobbering statement or the end of the IL ends it failing. */
2775 if ((int)limit
<= 0)
2778 if (stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
2780 bool disambiguate_only
= true;
2782 && (*translate
) (ref
, vuse
, data
, &disambiguate_only
) == NULL
)
2788 /* If we reach a new basic-block see if we already skipped it
2789 in a previous walk that ended successfully. */
2790 if (gimple_bb (def_stmt
) != bb
)
2792 if (!bitmap_set_bit (*visited
, SSA_NAME_VERSION (vuse
)))
2793 return !abort_on_visited
;
2794 bb
= gimple_bb (def_stmt
);
2796 vuse
= gimple_vuse (def_stmt
);
2802 /* Starting from a PHI node for the virtual operand of the memory reference
2803 REF find a continuation virtual operand that allows to continue walking
2804 statements dominating PHI skipping only statements that cannot possibly
2805 clobber REF. Decrements LIMIT for each alias disambiguation done
2806 and aborts the walk, returning NULL_TREE if it reaches zero.
2807 Returns NULL_TREE if no suitable virtual operand can be found. */
2810 get_continuation_for_phi (gimple
*phi
, ao_ref
*ref
,
2811 unsigned int &limit
, bitmap
*visited
,
2812 bool abort_on_visited
,
2813 void *(*translate
)(ao_ref
*, tree
, void *, bool *),
2816 unsigned nargs
= gimple_phi_num_args (phi
);
2818 /* Through a single-argument PHI we can simply look through. */
2820 return PHI_ARG_DEF (phi
, 0);
2822 /* For two or more arguments try to pairwise skip non-aliasing code
2823 until we hit the phi argument definition that dominates the other one. */
2824 basic_block phi_bb
= gimple_bb (phi
);
2828 /* Find a candidate for the virtual operand which definition
2829 dominates those of all others. */
2830 /* First look if any of the args themselves satisfy this. */
2831 for (i
= 0; i
< nargs
; ++i
)
2833 arg0
= PHI_ARG_DEF (phi
, i
);
2834 if (SSA_NAME_IS_DEFAULT_DEF (arg0
))
2836 basic_block def_bb
= gimple_bb (SSA_NAME_DEF_STMT (arg0
));
2837 if (def_bb
!= phi_bb
2838 && dominated_by_p (CDI_DOMINATORS
, phi_bb
, def_bb
))
2842 /* If not, look if we can reach such candidate by walking defs
2843 until we hit the immediate dominator. maybe_skip_until will
2845 basic_block dom
= get_immediate_dominator (CDI_DOMINATORS
, phi_bb
);
2847 /* Then check against the (to be) found candidate. */
2848 for (i
= 0; i
< nargs
; ++i
)
2850 arg1
= PHI_ARG_DEF (phi
, i
);
2853 else if (! maybe_skip_until (phi
, arg0
, dom
, ref
, arg1
, limit
, visited
,
2855 /* Do not translate when walking over
2859 gimple_bb (SSA_NAME_DEF_STMT (arg1
)),
2861 ? NULL
: translate
, data
))
2868 /* Based on the memory reference REF and its virtual use VUSE call
2869 WALKER for each virtual use that is equivalent to VUSE, including VUSE
2870 itself. That is, for each virtual use for which its defining statement
2871 does not clobber REF.
2873 WALKER is called with REF, the current virtual use and DATA. If
2874 WALKER returns non-NULL the walk stops and its result is returned.
2875 At the end of a non-successful walk NULL is returned.
2877 TRANSLATE if non-NULL is called with a pointer to REF, the virtual
2878 use which definition is a statement that may clobber REF and DATA.
2879 If TRANSLATE returns (void *)-1 the walk stops and NULL is returned.
2880 If TRANSLATE returns non-NULL the walk stops and its result is returned.
2881 If TRANSLATE returns NULL the walk continues and TRANSLATE is supposed
2882 to adjust REF and *DATA to make that valid.
2884 VALUEIZE if non-NULL is called with the next VUSE that is considered
2885 and return value is substituted for that. This can be used to
2886 implement optimistic value-numbering for example. Note that the
2887 VUSE argument is assumed to be valueized already.
2889 LIMIT specifies the number of alias queries we are allowed to do,
2890 the walk stops when it reaches zero and NULL is returned. LIMIT
2891 is decremented by the number of alias queries (plus adjustments
2892 done by the callbacks) upon return.
2894 TODO: Cache the vector of equivalent vuses per ref, vuse pair. */
2897 walk_non_aliased_vuses (ao_ref
*ref
, tree vuse
,
2898 void *(*walker
)(ao_ref
*, tree
, void *),
2899 void *(*translate
)(ao_ref
*, tree
, void *, bool *),
2900 tree (*valueize
)(tree
),
2901 unsigned &limit
, void *data
)
2903 bitmap visited
= NULL
;
2905 bool translated
= false;
2907 timevar_push (TV_ALIAS_STMT_WALK
);
2913 /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */
2914 res
= (*walker
) (ref
, vuse
, data
);
2916 if (res
== (void *)-1)
2921 /* Lookup succeeded. */
2922 else if (res
!= NULL
)
2927 vuse
= valueize (vuse
);
2934 def_stmt
= SSA_NAME_DEF_STMT (vuse
);
2935 if (gimple_nop_p (def_stmt
))
2937 else if (gimple_code (def_stmt
) == GIMPLE_PHI
)
2938 vuse
= get_continuation_for_phi (def_stmt
, ref
, limit
,
2939 &visited
, translated
, translate
, data
);
2942 if ((int)limit
<= 0)
2947 if (stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
2951 bool disambiguate_only
= false;
2952 res
= (*translate
) (ref
, vuse
, data
, &disambiguate_only
);
2953 /* Failed lookup and translation. */
2954 if (res
== (void *)-1)
2959 /* Lookup succeeded. */
2960 else if (res
!= NULL
)
2962 /* Translation succeeded, continue walking. */
2963 translated
= translated
|| !disambiguate_only
;
2965 vuse
= gimple_vuse (def_stmt
);
2971 BITMAP_FREE (visited
);
2973 timevar_pop (TV_ALIAS_STMT_WALK
);
2979 /* Based on the memory reference REF call WALKER for each vdef which
2980 defining statement may clobber REF, starting with VDEF. If REF
2981 is NULL_TREE, each defining statement is visited.
2983 WALKER is called with REF, the current vdef and DATA. If WALKER
2984 returns true the walk is stopped, otherwise it continues.
2986 If function entry is reached, FUNCTION_ENTRY_REACHED is set to true.
2987 The pointer may be NULL and then we do not track this information.
2989 At PHI nodes walk_aliased_vdefs forks into one walk for reach
2990 PHI argument (but only one walk continues on merge points), the
2991 return value is true if any of the walks was successful.
2993 The function returns the number of statements walked or -1 if
2994 LIMIT stmts were walked and the walk was aborted at this point.
2995 If LIMIT is zero the walk is not aborted. */
2998 walk_aliased_vdefs_1 (ao_ref
*ref
, tree vdef
,
2999 bool (*walker
)(ao_ref
*, tree
, void *), void *data
,
3000 bitmap
*visited
, unsigned int cnt
,
3001 bool *function_entry_reached
, unsigned limit
)
3005 gimple
*def_stmt
= SSA_NAME_DEF_STMT (vdef
);
3008 && !bitmap_set_bit (*visited
, SSA_NAME_VERSION (vdef
)))
3011 if (gimple_nop_p (def_stmt
))
3013 if (function_entry_reached
)
3014 *function_entry_reached
= true;
3017 else if (gimple_code (def_stmt
) == GIMPLE_PHI
)
3021 *visited
= BITMAP_ALLOC (NULL
);
3022 for (i
= 0; i
< gimple_phi_num_args (def_stmt
); ++i
)
3024 int res
= walk_aliased_vdefs_1 (ref
,
3025 gimple_phi_arg_def (def_stmt
, i
),
3026 walker
, data
, visited
, cnt
,
3027 function_entry_reached
, limit
);
3035 /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */
3040 || stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
3041 && (*walker
) (ref
, vdef
, data
))
3044 vdef
= gimple_vuse (def_stmt
);
3050 walk_aliased_vdefs (ao_ref
*ref
, tree vdef
,
3051 bool (*walker
)(ao_ref
*, tree
, void *), void *data
,
3053 bool *function_entry_reached
, unsigned int limit
)
3055 bitmap local_visited
= NULL
;
3058 timevar_push (TV_ALIAS_STMT_WALK
);
3060 if (function_entry_reached
)
3061 *function_entry_reached
= false;
3063 ret
= walk_aliased_vdefs_1 (ref
, vdef
, walker
, data
,
3064 visited
? visited
: &local_visited
, 0,
3065 function_entry_reached
, limit
);
3067 BITMAP_FREE (local_visited
);
3069 timevar_pop (TV_ALIAS_STMT_WALK
);