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;
864 /* Choose bases and base types to search for. */
866 while (handled_component_p (base1
))
867 base1
= TREE_OPERAND (base1
, 0);
868 type1
= TREE_TYPE (base1
);
870 while (handled_component_p (base2
))
871 base2
= TREE_OPERAND (base2
, 0);
872 type2
= TREE_TYPE (base2
);
874 /* Now search for the type1 in the access path of ref2. This
875 would be a common base for doing offset based disambiguation on.
876 This however only makes sense if type2 is big enough to hold type1. */
877 int cmp_outer
= compare_type_sizes (type2
, type1
);
883 /* We walk from inner type to the outer types. If type we see is
884 already too large to be part of type1, terminate the search. */
885 int cmp
= compare_type_sizes (type1
, TREE_TYPE (*refp
));
888 /* If types may be of same size, see if we can decide about their
892 same_p2
= same_type_for_tbaa (TREE_TYPE (*refp
), type1
);
896 if (!handled_component_p (*refp
))
898 refp
= &TREE_OPERAND (*refp
, 0);
902 poly_int64 offadj
, sztmp
, msztmp
;
904 get_ref_base_and_extent (*refp
, &offadj
, &sztmp
, &msztmp
, &reverse
);
906 get_ref_base_and_extent (base1
, &offadj
, &sztmp
, &msztmp
, &reverse
);
908 if (ranges_maybe_overlap_p (offset1
, max_size1
, offset2
, max_size2
))
910 ++alias_stats
.aliasing_component_refs_p_may_alias
;
915 ++alias_stats
.aliasing_component_refs_p_no_alias
;
921 /* If we didn't find a common base, try the other way around. */
927 int cmp
= compare_type_sizes (type2
, TREE_TYPE (*refp
));
930 /* If types may be of same size, see if we can decide about their
934 same_p1
= same_type_for_tbaa (TREE_TYPE (*refp
), type2
);
938 if (!handled_component_p (*refp
))
940 refp
= &TREE_OPERAND (*refp
, 0);
944 poly_int64 offadj
, sztmp
, msztmp
;
947 get_ref_base_and_extent (*refp
, &offadj
, &sztmp
, &msztmp
, &reverse
);
949 get_ref_base_and_extent (base2
, &offadj
, &sztmp
, &msztmp
, &reverse
);
951 if (ranges_maybe_overlap_p (offset1
, max_size1
, offset2
, max_size2
))
953 ++alias_stats
.aliasing_component_refs_p_may_alias
;
958 ++alias_stats
.aliasing_component_refs_p_no_alias
;
964 /* In the following code we make an assumption that the types in access
965 paths do not overlap and thus accesses alias only if one path can be
966 continuation of another. If we was not able to decide about equivalence,
967 we need to give up. */
968 if (same_p1
== -1 || same_p2
== -1)
971 /* If we have two type access paths B1.path1 and B2.path2 they may
972 only alias if either B1 is in B2.path2 or B2 is in B1.path1.
973 But we can still have a path that goes B1.path1...B2.path2 with
974 a part that we do not see. So we can only disambiguate now
975 if there is no B2 in the tail of path1 and no B1 on the
977 if (compare_type_sizes (TREE_TYPE (ref2
), type1
) >= 0
978 && type_has_components_p (TREE_TYPE (ref2
))
979 && (base1_alias_set
== ref2_alias_set
980 || alias_set_subset_of (base1_alias_set
, ref2_alias_set
)))
982 ++alias_stats
.aliasing_component_refs_p_may_alias
;
985 /* If this is ptr vs. decl then we know there is no ptr ... decl path. */
987 && compare_type_sizes (TREE_TYPE (ref1
), type2
) >= 0
988 && type_has_components_p (TREE_TYPE (ref1
))
989 && (base2_alias_set
== ref1_alias_set
990 || alias_set_subset_of (base2_alias_set
, ref1_alias_set
)))
992 ++alias_stats
.aliasing_component_refs_p_may_alias
;
995 ++alias_stats
.aliasing_component_refs_p_no_alias
;
999 /* Return true if we can determine that component references REF1 and REF2,
1000 that are within a common DECL, cannot overlap. */
1003 nonoverlapping_component_refs_of_decl_p (tree ref1
, tree ref2
)
1005 auto_vec
<tree
, 16> component_refs1
;
1006 auto_vec
<tree
, 16> component_refs2
;
1008 /* Create the stack of handled components for REF1. */
1009 while (handled_component_p (ref1
))
1011 component_refs1
.safe_push (ref1
);
1012 ref1
= TREE_OPERAND (ref1
, 0);
1014 if (TREE_CODE (ref1
) == MEM_REF
)
1016 if (!integer_zerop (TREE_OPERAND (ref1
, 1))
1017 || TREE_CODE (TREE_OPERAND (ref1
, 0)) != ADDR_EXPR
)
1019 ref1
= TREE_OPERAND (TREE_OPERAND (ref1
, 0), 0);
1022 /* Create the stack of handled components for REF2. */
1023 while (handled_component_p (ref2
))
1025 component_refs2
.safe_push (ref2
);
1026 ref2
= TREE_OPERAND (ref2
, 0);
1028 if (TREE_CODE (ref2
) == MEM_REF
)
1030 if (!integer_zerop (TREE_OPERAND (ref2
, 1))
1031 || TREE_CODE (TREE_OPERAND (ref2
, 0)) != ADDR_EXPR
)
1033 ref2
= TREE_OPERAND (TREE_OPERAND (ref2
, 0), 0);
1036 /* Bases must be either same or uncomparable. */
1037 gcc_checking_assert (ref1
== ref2
1038 || (DECL_P (ref1
) && DECL_P (ref2
)
1039 && compare_base_decls (ref1
, ref2
) != 0));
1041 /* Pop the stacks in parallel and examine the COMPONENT_REFs of the same
1042 rank. This is sufficient because we start from the same DECL and you
1043 cannot reference several fields at a time with COMPONENT_REFs (unlike
1044 with ARRAY_RANGE_REFs for arrays) so you always need the same number
1045 of them to access a sub-component, unless you're in a union, in which
1046 case the return value will precisely be false. */
1051 if (component_refs1
.is_empty ())
1053 ref1
= component_refs1
.pop ();
1055 while (!RECORD_OR_UNION_TYPE_P (TREE_TYPE (TREE_OPERAND (ref1
, 0))));
1059 if (component_refs2
.is_empty ())
1061 ref2
= component_refs2
.pop ();
1063 while (!RECORD_OR_UNION_TYPE_P (TREE_TYPE (TREE_OPERAND (ref2
, 0))));
1065 /* Beware of BIT_FIELD_REF. */
1066 if (TREE_CODE (ref1
) != COMPONENT_REF
1067 || TREE_CODE (ref2
) != COMPONENT_REF
)
1070 tree field1
= TREE_OPERAND (ref1
, 1);
1071 tree field2
= TREE_OPERAND (ref2
, 1);
1073 /* ??? We cannot simply use the type of operand #0 of the refs here
1074 as the Fortran compiler smuggles type punning into COMPONENT_REFs
1075 for common blocks instead of using unions like everyone else. */
1076 tree type1
= DECL_CONTEXT (field1
);
1077 tree type2
= DECL_CONTEXT (field2
);
1079 /* We cannot disambiguate fields in a union or qualified union. */
1080 if (type1
!= type2
|| TREE_CODE (type1
) != RECORD_TYPE
)
1083 if (field1
!= field2
)
1085 /* A field and its representative need to be considered the
1087 if (DECL_BIT_FIELD_REPRESENTATIVE (field1
) == field2
1088 || DECL_BIT_FIELD_REPRESENTATIVE (field2
) == field1
)
1090 /* Different fields of the same record type cannot overlap.
1091 ??? Bitfields can overlap at RTL level so punt on them. */
1092 if (DECL_BIT_FIELD (field1
) && DECL_BIT_FIELD (field2
))
1101 /* qsort compare function to sort FIELD_DECLs after their
1102 DECL_FIELD_CONTEXT TYPE_UID. */
1105 ncr_compar (const void *field1_
, const void *field2_
)
1107 const_tree field1
= *(const_tree
*) const_cast <void *>(field1_
);
1108 const_tree field2
= *(const_tree
*) const_cast <void *>(field2_
);
1109 unsigned int uid1
= TYPE_UID (DECL_FIELD_CONTEXT (field1
));
1110 unsigned int uid2
= TYPE_UID (DECL_FIELD_CONTEXT (field2
));
1113 else if (uid1
> uid2
)
1118 /* Return true if we can determine that the fields referenced cannot
1119 overlap for any pair of objects. */
1122 nonoverlapping_component_refs_p (const_tree x
, const_tree y
)
1124 if (!flag_strict_aliasing
1126 || TREE_CODE (x
) != COMPONENT_REF
1127 || TREE_CODE (y
) != COMPONENT_REF
)
1130 auto_vec
<const_tree
, 16> fieldsx
;
1131 while (TREE_CODE (x
) == COMPONENT_REF
)
1133 tree field
= TREE_OPERAND (x
, 1);
1134 tree type
= DECL_FIELD_CONTEXT (field
);
1135 if (TREE_CODE (type
) == RECORD_TYPE
)
1136 fieldsx
.safe_push (field
);
1137 x
= TREE_OPERAND (x
, 0);
1139 if (fieldsx
.length () == 0)
1141 auto_vec
<const_tree
, 16> fieldsy
;
1142 while (TREE_CODE (y
) == COMPONENT_REF
)
1144 tree field
= TREE_OPERAND (y
, 1);
1145 tree type
= DECL_FIELD_CONTEXT (field
);
1146 if (TREE_CODE (type
) == RECORD_TYPE
)
1147 fieldsy
.safe_push (TREE_OPERAND (y
, 1));
1148 y
= TREE_OPERAND (y
, 0);
1150 if (fieldsy
.length () == 0)
1153 /* Most common case first. */
1154 if (fieldsx
.length () == 1
1155 && fieldsy
.length () == 1)
1156 return ((DECL_FIELD_CONTEXT (fieldsx
[0])
1157 == DECL_FIELD_CONTEXT (fieldsy
[0]))
1158 && fieldsx
[0] != fieldsy
[0]
1159 && !(DECL_BIT_FIELD (fieldsx
[0]) && DECL_BIT_FIELD (fieldsy
[0])));
1161 if (fieldsx
.length () == 2)
1163 if (ncr_compar (&fieldsx
[0], &fieldsx
[1]) == 1)
1164 std::swap (fieldsx
[0], fieldsx
[1]);
1167 fieldsx
.qsort (ncr_compar
);
1169 if (fieldsy
.length () == 2)
1171 if (ncr_compar (&fieldsy
[0], &fieldsy
[1]) == 1)
1172 std::swap (fieldsy
[0], fieldsy
[1]);
1175 fieldsy
.qsort (ncr_compar
);
1177 unsigned i
= 0, j
= 0;
1180 const_tree fieldx
= fieldsx
[i
];
1181 const_tree fieldy
= fieldsy
[j
];
1182 tree typex
= DECL_FIELD_CONTEXT (fieldx
);
1183 tree typey
= DECL_FIELD_CONTEXT (fieldy
);
1186 /* We're left with accessing different fields of a structure,
1187 no possible overlap. */
1188 if (fieldx
!= fieldy
)
1190 /* A field and its representative need to be considered the
1192 if (DECL_BIT_FIELD_REPRESENTATIVE (fieldx
) == fieldy
1193 || DECL_BIT_FIELD_REPRESENTATIVE (fieldy
) == fieldx
)
1195 /* Different fields of the same record type cannot overlap.
1196 ??? Bitfields can overlap at RTL level so punt on them. */
1197 if (DECL_BIT_FIELD (fieldx
) && DECL_BIT_FIELD (fieldy
))
1202 if (TYPE_UID (typex
) < TYPE_UID (typey
))
1205 if (i
== fieldsx
.length ())
1211 if (j
== fieldsy
.length ())
1221 /* Return true if two memory references based on the variables BASE1
1222 and BASE2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and
1223 [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. REF1 and REF2
1224 if non-NULL are the complete memory reference trees. */
1227 decl_refs_may_alias_p (tree ref1
, tree base1
,
1228 poly_int64 offset1
, poly_int64 max_size1
,
1229 tree ref2
, tree base2
,
1230 poly_int64 offset2
, poly_int64 max_size2
)
1232 gcc_checking_assert (DECL_P (base1
) && DECL_P (base2
));
1234 /* If both references are based on different variables, they cannot alias. */
1235 if (compare_base_decls (base1
, base2
) == 0)
1238 /* If both references are based on the same variable, they cannot alias if
1239 the accesses do not overlap. */
1240 if (!ranges_maybe_overlap_p (offset1
, max_size1
, offset2
, max_size2
))
1243 /* For components with variable position, the above test isn't sufficient,
1244 so we disambiguate component references manually. */
1246 && handled_component_p (ref1
) && handled_component_p (ref2
)
1247 && nonoverlapping_component_refs_of_decl_p (ref1
, ref2
))
1253 /* Return true if an indirect reference based on *PTR1 constrained
1254 to [OFFSET1, OFFSET1 + MAX_SIZE1) may alias a variable based on BASE2
1255 constrained to [OFFSET2, OFFSET2 + MAX_SIZE2). *PTR1 and BASE2 have
1256 the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1
1257 in which case they are computed on-demand. REF1 and REF2
1258 if non-NULL are the complete memory reference trees. */
1261 indirect_ref_may_alias_decl_p (tree ref1 ATTRIBUTE_UNUSED
, tree base1
,
1262 poly_int64 offset1
, poly_int64 max_size1
,
1263 alias_set_type ref1_alias_set
,
1264 alias_set_type base1_alias_set
,
1265 tree ref2 ATTRIBUTE_UNUSED
, tree base2
,
1266 poly_int64 offset2
, poly_int64 max_size2
,
1267 alias_set_type ref2_alias_set
,
1268 alias_set_type base2_alias_set
, bool tbaa_p
)
1271 tree ptrtype1
, dbase2
;
1273 gcc_checking_assert ((TREE_CODE (base1
) == MEM_REF
1274 || TREE_CODE (base1
) == TARGET_MEM_REF
)
1277 ptr1
= TREE_OPERAND (base1
, 0);
1278 poly_offset_int moff
= mem_ref_offset (base1
) << LOG2_BITS_PER_UNIT
;
1280 /* If only one reference is based on a variable, they cannot alias if
1281 the pointer access is beyond the extent of the variable access.
1282 (the pointer base cannot validly point to an offset less than zero
1284 ??? IVOPTs creates bases that do not honor this restriction,
1285 so do not apply this optimization for TARGET_MEM_REFs. */
1286 if (TREE_CODE (base1
) != TARGET_MEM_REF
1287 && !ranges_maybe_overlap_p (offset1
+ moff
, -1, offset2
, max_size2
))
1289 /* They also cannot alias if the pointer may not point to the decl. */
1290 if (!ptr_deref_may_alias_decl_p (ptr1
, base2
))
1293 /* Disambiguations that rely on strict aliasing rules follow. */
1294 if (!flag_strict_aliasing
|| !tbaa_p
)
1297 ptrtype1
= TREE_TYPE (TREE_OPERAND (base1
, 1));
1299 /* If the alias set for a pointer access is zero all bets are off. */
1300 if (base1_alias_set
== 0)
1303 /* When we are trying to disambiguate an access with a pointer dereference
1304 as base versus one with a decl as base we can use both the size
1305 of the decl and its dynamic type for extra disambiguation.
1306 ??? We do not know anything about the dynamic type of the decl
1307 other than that its alias-set contains base2_alias_set as a subset
1308 which does not help us here. */
1309 /* As we know nothing useful about the dynamic type of the decl just
1310 use the usual conflict check rather than a subset test.
1311 ??? We could introduce -fvery-strict-aliasing when the language
1312 does not allow decls to have a dynamic type that differs from their
1313 static type. Then we can check
1314 !alias_set_subset_of (base1_alias_set, base2_alias_set) instead. */
1315 if (base1_alias_set
!= base2_alias_set
1316 && !alias_sets_conflict_p (base1_alias_set
, base2_alias_set
))
1318 /* If the size of the access relevant for TBAA through the pointer
1319 is bigger than the size of the decl we can't possibly access the
1320 decl via that pointer. */
1321 if (/* ??? This in turn may run afoul when a decl of type T which is
1322 a member of union type U is accessed through a pointer to
1323 type U and sizeof T is smaller than sizeof U. */
1324 TREE_CODE (TREE_TYPE (ptrtype1
)) != UNION_TYPE
1325 && TREE_CODE (TREE_TYPE (ptrtype1
)) != QUAL_UNION_TYPE
1326 && compare_sizes (DECL_SIZE (base2
),
1327 TYPE_SIZE (TREE_TYPE (ptrtype1
))) < 0)
1333 /* If the decl is accessed via a MEM_REF, reconstruct the base
1334 we can use for TBAA and an appropriately adjusted offset. */
1336 while (handled_component_p (dbase2
))
1337 dbase2
= TREE_OPERAND (dbase2
, 0);
1338 poly_int64 doffset1
= offset1
;
1339 poly_offset_int doffset2
= offset2
;
1340 if (TREE_CODE (dbase2
) == MEM_REF
1341 || TREE_CODE (dbase2
) == TARGET_MEM_REF
)
1342 doffset2
-= mem_ref_offset (dbase2
) << LOG2_BITS_PER_UNIT
;
1344 /* If either reference is view-converted, give up now. */
1345 if (same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (ptrtype1
)) != 1
1346 || same_type_for_tbaa (TREE_TYPE (dbase2
), TREE_TYPE (base2
)) != 1)
1349 /* If both references are through the same type, they do not alias
1350 if the accesses do not overlap. This does extra disambiguation
1351 for mixed/pointer accesses but requires strict aliasing.
1352 For MEM_REFs we require that the component-ref offset we computed
1353 is relative to the start of the type which we ensure by
1354 comparing rvalue and access type and disregarding the constant
1356 if ((TREE_CODE (base1
) != TARGET_MEM_REF
1357 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1358 && same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (dbase2
)) == 1)
1359 return ranges_maybe_overlap_p (doffset1
, max_size1
, doffset2
, max_size2
);
1362 && nonoverlapping_component_refs_p (ref1
, ref2
))
1365 /* Do access-path based disambiguation. */
1367 && (handled_component_p (ref1
) || handled_component_p (ref2
)))
1368 return aliasing_component_refs_p (ref1
,
1369 ref1_alias_set
, base1_alias_set
,
1372 ref2_alias_set
, base2_alias_set
,
1373 offset2
, max_size2
, true);
1378 /* Return true if two indirect references based on *PTR1
1379 and *PTR2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and
1380 [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. *PTR1 and *PTR2 have
1381 the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1
1382 in which case they are computed on-demand. REF1 and REF2
1383 if non-NULL are the complete memory reference trees. */
1386 indirect_refs_may_alias_p (tree ref1 ATTRIBUTE_UNUSED
, tree base1
,
1387 poly_int64 offset1
, poly_int64 max_size1
,
1388 alias_set_type ref1_alias_set
,
1389 alias_set_type base1_alias_set
,
1390 tree ref2 ATTRIBUTE_UNUSED
, tree base2
,
1391 poly_int64 offset2
, poly_int64 max_size2
,
1392 alias_set_type ref2_alias_set
,
1393 alias_set_type base2_alias_set
, bool tbaa_p
)
1397 tree ptrtype1
, ptrtype2
;
1399 gcc_checking_assert ((TREE_CODE (base1
) == MEM_REF
1400 || TREE_CODE (base1
) == TARGET_MEM_REF
)
1401 && (TREE_CODE (base2
) == MEM_REF
1402 || TREE_CODE (base2
) == TARGET_MEM_REF
));
1404 ptr1
= TREE_OPERAND (base1
, 0);
1405 ptr2
= TREE_OPERAND (base2
, 0);
1407 /* If both bases are based on pointers they cannot alias if they may not
1408 point to the same memory object or if they point to the same object
1409 and the accesses do not overlap. */
1410 if ((!cfun
|| gimple_in_ssa_p (cfun
))
1411 && operand_equal_p (ptr1
, ptr2
, 0)
1412 && (((TREE_CODE (base1
) != TARGET_MEM_REF
1413 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1414 && (TREE_CODE (base2
) != TARGET_MEM_REF
1415 || (!TMR_INDEX (base2
) && !TMR_INDEX2 (base2
))))
1416 || (TREE_CODE (base1
) == TARGET_MEM_REF
1417 && TREE_CODE (base2
) == TARGET_MEM_REF
1418 && (TMR_STEP (base1
) == TMR_STEP (base2
)
1419 || (TMR_STEP (base1
) && TMR_STEP (base2
)
1420 && operand_equal_p (TMR_STEP (base1
),
1421 TMR_STEP (base2
), 0)))
1422 && (TMR_INDEX (base1
) == TMR_INDEX (base2
)
1423 || (TMR_INDEX (base1
) && TMR_INDEX (base2
)
1424 && operand_equal_p (TMR_INDEX (base1
),
1425 TMR_INDEX (base2
), 0)))
1426 && (TMR_INDEX2 (base1
) == TMR_INDEX2 (base2
)
1427 || (TMR_INDEX2 (base1
) && TMR_INDEX2 (base2
)
1428 && operand_equal_p (TMR_INDEX2 (base1
),
1429 TMR_INDEX2 (base2
), 0))))))
1431 poly_offset_int moff1
= mem_ref_offset (base1
) << LOG2_BITS_PER_UNIT
;
1432 poly_offset_int moff2
= mem_ref_offset (base2
) << LOG2_BITS_PER_UNIT
;
1433 return ranges_maybe_overlap_p (offset1
+ moff1
, max_size1
,
1434 offset2
+ moff2
, max_size2
);
1436 if (!ptr_derefs_may_alias_p (ptr1
, ptr2
))
1439 /* Disambiguations that rely on strict aliasing rules follow. */
1440 if (!flag_strict_aliasing
|| !tbaa_p
)
1443 ptrtype1
= TREE_TYPE (TREE_OPERAND (base1
, 1));
1444 ptrtype2
= TREE_TYPE (TREE_OPERAND (base2
, 1));
1446 /* If the alias set for a pointer access is zero all bets are off. */
1447 if (base1_alias_set
== 0
1448 || base2_alias_set
== 0)
1451 /* If both references are through the same type, they do not alias
1452 if the accesses do not overlap. This does extra disambiguation
1453 for mixed/pointer accesses but requires strict aliasing. */
1454 if ((TREE_CODE (base1
) != TARGET_MEM_REF
1455 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1456 && (TREE_CODE (base2
) != TARGET_MEM_REF
1457 || (!TMR_INDEX (base2
) && !TMR_INDEX2 (base2
)))
1458 && same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (ptrtype1
)) == 1
1459 && same_type_for_tbaa (TREE_TYPE (base2
), TREE_TYPE (ptrtype2
)) == 1
1460 && same_type_for_tbaa (TREE_TYPE (ptrtype1
),
1461 TREE_TYPE (ptrtype2
)) == 1
1462 /* But avoid treating arrays as "objects", instead assume they
1463 can overlap by an exact multiple of their element size. */
1464 && TREE_CODE (TREE_TYPE (ptrtype1
)) != ARRAY_TYPE
)
1465 return ranges_maybe_overlap_p (offset1
, max_size1
, offset2
, max_size2
);
1467 /* Do type-based disambiguation. */
1468 if (base1_alias_set
!= base2_alias_set
1469 && !alias_sets_conflict_p (base1_alias_set
, base2_alias_set
))
1472 /* If either reference is view-converted, give up now. */
1473 if (same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (ptrtype1
)) != 1
1474 || same_type_for_tbaa (TREE_TYPE (base2
), TREE_TYPE (ptrtype2
)) != 1)
1478 && nonoverlapping_component_refs_p (ref1
, ref2
))
1481 /* Do access-path based disambiguation. */
1483 && (handled_component_p (ref1
) || handled_component_p (ref2
)))
1484 return aliasing_component_refs_p (ref1
,
1485 ref1_alias_set
, base1_alias_set
,
1488 ref2_alias_set
, base2_alias_set
,
1489 offset2
, max_size2
, false);
1494 /* Return true, if the two memory references REF1 and REF2 may alias. */
1497 refs_may_alias_p_2 (ao_ref
*ref1
, ao_ref
*ref2
, bool tbaa_p
)
1500 poly_int64 offset1
= 0, offset2
= 0;
1501 poly_int64 max_size1
= -1, max_size2
= -1;
1502 bool var1_p
, var2_p
, ind1_p
, ind2_p
;
1504 gcc_checking_assert ((!ref1
->ref
1505 || TREE_CODE (ref1
->ref
) == SSA_NAME
1506 || DECL_P (ref1
->ref
)
1507 || TREE_CODE (ref1
->ref
) == STRING_CST
1508 || handled_component_p (ref1
->ref
)
1509 || TREE_CODE (ref1
->ref
) == MEM_REF
1510 || TREE_CODE (ref1
->ref
) == TARGET_MEM_REF
)
1512 || TREE_CODE (ref2
->ref
) == SSA_NAME
1513 || DECL_P (ref2
->ref
)
1514 || TREE_CODE (ref2
->ref
) == STRING_CST
1515 || handled_component_p (ref2
->ref
)
1516 || TREE_CODE (ref2
->ref
) == MEM_REF
1517 || TREE_CODE (ref2
->ref
) == TARGET_MEM_REF
));
1519 /* Decompose the references into their base objects and the access. */
1520 base1
= ao_ref_base (ref1
);
1521 offset1
= ref1
->offset
;
1522 max_size1
= ref1
->max_size
;
1523 base2
= ao_ref_base (ref2
);
1524 offset2
= ref2
->offset
;
1525 max_size2
= ref2
->max_size
;
1527 /* We can end up with registers or constants as bases for example from
1528 *D.1663_44 = VIEW_CONVERT_EXPR<struct DB_LSN>(__tmp$B0F64_59);
1529 which is seen as a struct copy. */
1530 if (TREE_CODE (base1
) == SSA_NAME
1531 || TREE_CODE (base1
) == CONST_DECL
1532 || TREE_CODE (base1
) == CONSTRUCTOR
1533 || TREE_CODE (base1
) == ADDR_EXPR
1534 || CONSTANT_CLASS_P (base1
)
1535 || TREE_CODE (base2
) == SSA_NAME
1536 || TREE_CODE (base2
) == CONST_DECL
1537 || TREE_CODE (base2
) == CONSTRUCTOR
1538 || TREE_CODE (base2
) == ADDR_EXPR
1539 || CONSTANT_CLASS_P (base2
))
1542 /* We can end up referring to code via function and label decls.
1543 As we likely do not properly track code aliases conservatively
1545 if (TREE_CODE (base1
) == FUNCTION_DECL
1546 || TREE_CODE (base1
) == LABEL_DECL
1547 || TREE_CODE (base2
) == FUNCTION_DECL
1548 || TREE_CODE (base2
) == LABEL_DECL
)
1551 /* Two volatile accesses always conflict. */
1552 if (ref1
->volatile_p
1553 && ref2
->volatile_p
)
1556 /* Defer to simple offset based disambiguation if we have
1557 references based on two decls. Do this before defering to
1558 TBAA to handle must-alias cases in conformance with the
1559 GCC extension of allowing type-punning through unions. */
1560 var1_p
= DECL_P (base1
);
1561 var2_p
= DECL_P (base2
);
1562 if (var1_p
&& var2_p
)
1563 return decl_refs_may_alias_p (ref1
->ref
, base1
, offset1
, max_size1
,
1564 ref2
->ref
, base2
, offset2
, max_size2
);
1566 /* Handle restrict based accesses.
1567 ??? ao_ref_base strips inner MEM_REF [&decl], recover from that
1569 tree rbase1
= base1
;
1570 tree rbase2
= base2
;
1575 while (handled_component_p (rbase1
))
1576 rbase1
= TREE_OPERAND (rbase1
, 0);
1582 while (handled_component_p (rbase2
))
1583 rbase2
= TREE_OPERAND (rbase2
, 0);
1585 if (rbase1
&& rbase2
1586 && (TREE_CODE (base1
) == MEM_REF
|| TREE_CODE (base1
) == TARGET_MEM_REF
)
1587 && (TREE_CODE (base2
) == MEM_REF
|| TREE_CODE (base2
) == TARGET_MEM_REF
)
1588 /* If the accesses are in the same restrict clique... */
1589 && MR_DEPENDENCE_CLIQUE (base1
) == MR_DEPENDENCE_CLIQUE (base2
)
1590 /* But based on different pointers they do not alias. */
1591 && MR_DEPENDENCE_BASE (base1
) != MR_DEPENDENCE_BASE (base2
))
1594 ind1_p
= (TREE_CODE (base1
) == MEM_REF
1595 || TREE_CODE (base1
) == TARGET_MEM_REF
);
1596 ind2_p
= (TREE_CODE (base2
) == MEM_REF
1597 || TREE_CODE (base2
) == TARGET_MEM_REF
);
1599 /* Canonicalize the pointer-vs-decl case. */
1600 if (ind1_p
&& var2_p
)
1602 std::swap (offset1
, offset2
);
1603 std::swap (max_size1
, max_size2
);
1604 std::swap (base1
, base2
);
1605 std::swap (ref1
, ref2
);
1612 /* First defer to TBAA if possible. */
1614 && flag_strict_aliasing
1615 && !alias_sets_conflict_p (ao_ref_alias_set (ref1
),
1616 ao_ref_alias_set (ref2
)))
1619 /* If the reference is based on a pointer that points to memory
1620 that may not be written to then the other reference cannot possibly
1622 if ((TREE_CODE (TREE_OPERAND (base2
, 0)) == SSA_NAME
1623 && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base2
, 0)))
1625 && TREE_CODE (TREE_OPERAND (base1
, 0)) == SSA_NAME
1626 && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base1
, 0))))
1629 /* Dispatch to the pointer-vs-decl or pointer-vs-pointer disambiguators. */
1630 if (var1_p
&& ind2_p
)
1631 return indirect_ref_may_alias_decl_p (ref2
->ref
, base2
,
1633 ao_ref_alias_set (ref2
),
1634 ao_ref_base_alias_set (ref2
),
1637 ao_ref_alias_set (ref1
),
1638 ao_ref_base_alias_set (ref1
),
1640 else if (ind1_p
&& ind2_p
)
1641 return indirect_refs_may_alias_p (ref1
->ref
, base1
,
1643 ao_ref_alias_set (ref1
),
1644 ao_ref_base_alias_set (ref1
),
1647 ao_ref_alias_set (ref2
),
1648 ao_ref_base_alias_set (ref2
),
1654 /* Return true, if the two memory references REF1 and REF2 may alias
1655 and update statistics. */
1658 refs_may_alias_p_1 (ao_ref
*ref1
, ao_ref
*ref2
, bool tbaa_p
)
1660 bool res
= refs_may_alias_p_2 (ref1
, ref2
, tbaa_p
);
1662 ++alias_stats
.refs_may_alias_p_may_alias
;
1664 ++alias_stats
.refs_may_alias_p_no_alias
;
1669 refs_may_alias_p (tree ref1
, ao_ref
*ref2
, bool tbaa_p
)
1672 ao_ref_init (&r1
, ref1
);
1673 return refs_may_alias_p_1 (&r1
, ref2
, tbaa_p
);
1677 refs_may_alias_p (tree ref1
, tree ref2
, bool tbaa_p
)
1680 ao_ref_init (&r1
, ref1
);
1681 ao_ref_init (&r2
, ref2
);
1682 return refs_may_alias_p_1 (&r1
, &r2
, tbaa_p
);
1685 /* Returns true if there is a anti-dependence for the STORE that
1686 executes after the LOAD. */
1689 refs_anti_dependent_p (tree load
, tree store
)
1692 ao_ref_init (&r1
, load
);
1693 ao_ref_init (&r2
, store
);
1694 return refs_may_alias_p_1 (&r1
, &r2
, false);
1697 /* Returns true if there is a output dependence for the stores
1698 STORE1 and STORE2. */
1701 refs_output_dependent_p (tree store1
, tree store2
)
1704 ao_ref_init (&r1
, store1
);
1705 ao_ref_init (&r2
, store2
);
1706 return refs_may_alias_p_1 (&r1
, &r2
, false);
1709 /* If the call CALL may use the memory reference REF return true,
1710 otherwise return false. */
1713 ref_maybe_used_by_call_p_1 (gcall
*call
, ao_ref
*ref
, bool tbaa_p
)
1717 int flags
= gimple_call_flags (call
);
1719 /* Const functions without a static chain do not implicitly use memory. */
1720 if (!gimple_call_chain (call
)
1721 && (flags
& (ECF_CONST
|ECF_NOVOPS
)))
1724 base
= ao_ref_base (ref
);
1728 /* A call that is not without side-effects might involve volatile
1729 accesses and thus conflicts with all other volatile accesses. */
1730 if (ref
->volatile_p
)
1733 /* If the reference is based on a decl that is not aliased the call
1734 cannot possibly use it. */
1736 && !may_be_aliased (base
)
1737 /* But local statics can be used through recursion. */
1738 && !is_global_var (base
))
1741 callee
= gimple_call_fndecl (call
);
1743 /* Handle those builtin functions explicitly that do not act as
1744 escape points. See tree-ssa-structalias.c:find_func_aliases
1745 for the list of builtins we might need to handle here. */
1746 if (callee
!= NULL_TREE
1747 && gimple_call_builtin_p (call
, BUILT_IN_NORMAL
))
1748 switch (DECL_FUNCTION_CODE (callee
))
1750 /* All the following functions read memory pointed to by
1751 their second argument. strcat/strncat additionally
1752 reads memory pointed to by the first argument. */
1753 case BUILT_IN_STRCAT
:
1754 case BUILT_IN_STRNCAT
:
1757 ao_ref_init_from_ptr_and_size (&dref
,
1758 gimple_call_arg (call
, 0),
1760 if (refs_may_alias_p_1 (&dref
, ref
, false))
1764 case BUILT_IN_STRCPY
:
1765 case BUILT_IN_STRNCPY
:
1766 case BUILT_IN_MEMCPY
:
1767 case BUILT_IN_MEMMOVE
:
1768 case BUILT_IN_MEMPCPY
:
1769 case BUILT_IN_STPCPY
:
1770 case BUILT_IN_STPNCPY
:
1771 case BUILT_IN_TM_MEMCPY
:
1772 case BUILT_IN_TM_MEMMOVE
:
1775 tree size
= NULL_TREE
;
1776 if (gimple_call_num_args (call
) == 3)
1777 size
= gimple_call_arg (call
, 2);
1778 ao_ref_init_from_ptr_and_size (&dref
,
1779 gimple_call_arg (call
, 1),
1781 return refs_may_alias_p_1 (&dref
, ref
, false);
1783 case BUILT_IN_STRCAT_CHK
:
1784 case BUILT_IN_STRNCAT_CHK
:
1787 ao_ref_init_from_ptr_and_size (&dref
,
1788 gimple_call_arg (call
, 0),
1790 if (refs_may_alias_p_1 (&dref
, ref
, false))
1794 case BUILT_IN_STRCPY_CHK
:
1795 case BUILT_IN_STRNCPY_CHK
:
1796 case BUILT_IN_MEMCPY_CHK
:
1797 case BUILT_IN_MEMMOVE_CHK
:
1798 case BUILT_IN_MEMPCPY_CHK
:
1799 case BUILT_IN_STPCPY_CHK
:
1800 case BUILT_IN_STPNCPY_CHK
:
1803 tree size
= NULL_TREE
;
1804 if (gimple_call_num_args (call
) == 4)
1805 size
= gimple_call_arg (call
, 2);
1806 ao_ref_init_from_ptr_and_size (&dref
,
1807 gimple_call_arg (call
, 1),
1809 return refs_may_alias_p_1 (&dref
, ref
, false);
1811 case BUILT_IN_BCOPY
:
1814 tree size
= gimple_call_arg (call
, 2);
1815 ao_ref_init_from_ptr_and_size (&dref
,
1816 gimple_call_arg (call
, 0),
1818 return refs_may_alias_p_1 (&dref
, ref
, false);
1821 /* The following functions read memory pointed to by their
1823 CASE_BUILT_IN_TM_LOAD (1):
1824 CASE_BUILT_IN_TM_LOAD (2):
1825 CASE_BUILT_IN_TM_LOAD (4):
1826 CASE_BUILT_IN_TM_LOAD (8):
1827 CASE_BUILT_IN_TM_LOAD (FLOAT
):
1828 CASE_BUILT_IN_TM_LOAD (DOUBLE
):
1829 CASE_BUILT_IN_TM_LOAD (LDOUBLE
):
1830 CASE_BUILT_IN_TM_LOAD (M64
):
1831 CASE_BUILT_IN_TM_LOAD (M128
):
1832 CASE_BUILT_IN_TM_LOAD (M256
):
1833 case BUILT_IN_TM_LOG
:
1834 case BUILT_IN_TM_LOG_1
:
1835 case BUILT_IN_TM_LOG_2
:
1836 case BUILT_IN_TM_LOG_4
:
1837 case BUILT_IN_TM_LOG_8
:
1838 case BUILT_IN_TM_LOG_FLOAT
:
1839 case BUILT_IN_TM_LOG_DOUBLE
:
1840 case BUILT_IN_TM_LOG_LDOUBLE
:
1841 case BUILT_IN_TM_LOG_M64
:
1842 case BUILT_IN_TM_LOG_M128
:
1843 case BUILT_IN_TM_LOG_M256
:
1844 return ptr_deref_may_alias_ref_p_1 (gimple_call_arg (call
, 0), ref
);
1846 /* These read memory pointed to by the first argument. */
1847 case BUILT_IN_STRDUP
:
1848 case BUILT_IN_STRNDUP
:
1849 case BUILT_IN_REALLOC
:
1852 tree size
= NULL_TREE
;
1853 if (gimple_call_num_args (call
) == 2)
1854 size
= gimple_call_arg (call
, 1);
1855 ao_ref_init_from_ptr_and_size (&dref
,
1856 gimple_call_arg (call
, 0),
1858 return refs_may_alias_p_1 (&dref
, ref
, false);
1860 /* These read memory pointed to by the first argument. */
1861 case BUILT_IN_INDEX
:
1862 case BUILT_IN_STRCHR
:
1863 case BUILT_IN_STRRCHR
:
1866 ao_ref_init_from_ptr_and_size (&dref
,
1867 gimple_call_arg (call
, 0),
1869 return refs_may_alias_p_1 (&dref
, ref
, false);
1871 /* These read memory pointed to by the first argument with size
1872 in the third argument. */
1873 case BUILT_IN_MEMCHR
:
1876 ao_ref_init_from_ptr_and_size (&dref
,
1877 gimple_call_arg (call
, 0),
1878 gimple_call_arg (call
, 2));
1879 return refs_may_alias_p_1 (&dref
, ref
, false);
1881 /* These read memory pointed to by the first and second arguments. */
1882 case BUILT_IN_STRSTR
:
1883 case BUILT_IN_STRPBRK
:
1886 ao_ref_init_from_ptr_and_size (&dref
,
1887 gimple_call_arg (call
, 0),
1889 if (refs_may_alias_p_1 (&dref
, ref
, false))
1891 ao_ref_init_from_ptr_and_size (&dref
,
1892 gimple_call_arg (call
, 1),
1894 return refs_may_alias_p_1 (&dref
, ref
, false);
1897 /* The following builtins do not read from memory. */
1899 case BUILT_IN_MALLOC
:
1900 case BUILT_IN_POSIX_MEMALIGN
:
1901 case BUILT_IN_ALIGNED_ALLOC
:
1902 case BUILT_IN_CALLOC
:
1903 CASE_BUILT_IN_ALLOCA
:
1904 case BUILT_IN_STACK_SAVE
:
1905 case BUILT_IN_STACK_RESTORE
:
1906 case BUILT_IN_MEMSET
:
1907 case BUILT_IN_TM_MEMSET
:
1908 case BUILT_IN_MEMSET_CHK
:
1909 case BUILT_IN_FREXP
:
1910 case BUILT_IN_FREXPF
:
1911 case BUILT_IN_FREXPL
:
1912 case BUILT_IN_GAMMA_R
:
1913 case BUILT_IN_GAMMAF_R
:
1914 case BUILT_IN_GAMMAL_R
:
1915 case BUILT_IN_LGAMMA_R
:
1916 case BUILT_IN_LGAMMAF_R
:
1917 case BUILT_IN_LGAMMAL_R
:
1919 case BUILT_IN_MODFF
:
1920 case BUILT_IN_MODFL
:
1921 case BUILT_IN_REMQUO
:
1922 case BUILT_IN_REMQUOF
:
1923 case BUILT_IN_REMQUOL
:
1924 case BUILT_IN_SINCOS
:
1925 case BUILT_IN_SINCOSF
:
1926 case BUILT_IN_SINCOSL
:
1927 case BUILT_IN_ASSUME_ALIGNED
:
1928 case BUILT_IN_VA_END
:
1930 /* __sync_* builtins and some OpenMP builtins act as threading
1932 #undef DEF_SYNC_BUILTIN
1933 #define DEF_SYNC_BUILTIN(ENUM, NAME, TYPE, ATTRS) case ENUM:
1934 #include "sync-builtins.def"
1935 #undef DEF_SYNC_BUILTIN
1936 case BUILT_IN_GOMP_ATOMIC_START
:
1937 case BUILT_IN_GOMP_ATOMIC_END
:
1938 case BUILT_IN_GOMP_BARRIER
:
1939 case BUILT_IN_GOMP_BARRIER_CANCEL
:
1940 case BUILT_IN_GOMP_TASKWAIT
:
1941 case BUILT_IN_GOMP_TASKGROUP_END
:
1942 case BUILT_IN_GOMP_CRITICAL_START
:
1943 case BUILT_IN_GOMP_CRITICAL_END
:
1944 case BUILT_IN_GOMP_CRITICAL_NAME_START
:
1945 case BUILT_IN_GOMP_CRITICAL_NAME_END
:
1946 case BUILT_IN_GOMP_LOOP_END
:
1947 case BUILT_IN_GOMP_LOOP_END_CANCEL
:
1948 case BUILT_IN_GOMP_ORDERED_START
:
1949 case BUILT_IN_GOMP_ORDERED_END
:
1950 case BUILT_IN_GOMP_SECTIONS_END
:
1951 case BUILT_IN_GOMP_SECTIONS_END_CANCEL
:
1952 case BUILT_IN_GOMP_SINGLE_COPY_START
:
1953 case BUILT_IN_GOMP_SINGLE_COPY_END
:
1957 /* Fallthru to general call handling. */;
1960 /* Check if base is a global static variable that is not read
1962 if (callee
!= NULL_TREE
&& VAR_P (base
) && TREE_STATIC (base
))
1964 struct cgraph_node
*node
= cgraph_node::get (callee
);
1967 /* FIXME: Callee can be an OMP builtin that does not have a call graph
1968 node yet. We should enforce that there are nodes for all decls in the
1969 IL and remove this check instead. */
1971 && (not_read
= ipa_reference_get_not_read_global (node
))
1972 && bitmap_bit_p (not_read
, ipa_reference_var_uid (base
)))
1976 /* Check if the base variable is call-used. */
1979 if (pt_solution_includes (gimple_call_use_set (call
), base
))
1982 else if ((TREE_CODE (base
) == MEM_REF
1983 || TREE_CODE (base
) == TARGET_MEM_REF
)
1984 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
)
1986 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (TREE_OPERAND (base
, 0));
1990 if (pt_solutions_intersect (gimple_call_use_set (call
), &pi
->pt
))
1996 /* Inspect call arguments for passed-by-value aliases. */
1998 for (i
= 0; i
< gimple_call_num_args (call
); ++i
)
2000 tree op
= gimple_call_arg (call
, i
);
2001 int flags
= gimple_call_arg_flags (call
, i
);
2003 if (flags
& EAF_UNUSED
)
2006 if (TREE_CODE (op
) == WITH_SIZE_EXPR
)
2007 op
= TREE_OPERAND (op
, 0);
2009 if (TREE_CODE (op
) != SSA_NAME
2010 && !is_gimple_min_invariant (op
))
2013 ao_ref_init (&r
, op
);
2014 if (refs_may_alias_p_1 (&r
, ref
, tbaa_p
))
2023 ref_maybe_used_by_call_p (gcall
*call
, ao_ref
*ref
, bool tbaa_p
)
2026 res
= ref_maybe_used_by_call_p_1 (call
, ref
, tbaa_p
);
2028 ++alias_stats
.ref_maybe_used_by_call_p_may_alias
;
2030 ++alias_stats
.ref_maybe_used_by_call_p_no_alias
;
2035 /* If the statement STMT may use the memory reference REF return
2036 true, otherwise return false. */
2039 ref_maybe_used_by_stmt_p (gimple
*stmt
, ao_ref
*ref
, bool tbaa_p
)
2041 if (is_gimple_assign (stmt
))
2045 /* All memory assign statements are single. */
2046 if (!gimple_assign_single_p (stmt
))
2049 rhs
= gimple_assign_rhs1 (stmt
);
2050 if (is_gimple_reg (rhs
)
2051 || is_gimple_min_invariant (rhs
)
2052 || gimple_assign_rhs_code (stmt
) == CONSTRUCTOR
)
2055 return refs_may_alias_p (rhs
, ref
, tbaa_p
);
2057 else if (is_gimple_call (stmt
))
2058 return ref_maybe_used_by_call_p (as_a
<gcall
*> (stmt
), ref
, tbaa_p
);
2059 else if (greturn
*return_stmt
= dyn_cast
<greturn
*> (stmt
))
2061 tree retval
= gimple_return_retval (return_stmt
);
2063 && TREE_CODE (retval
) != SSA_NAME
2064 && !is_gimple_min_invariant (retval
)
2065 && refs_may_alias_p (retval
, ref
, tbaa_p
))
2067 /* If ref escapes the function then the return acts as a use. */
2068 tree base
= ao_ref_base (ref
);
2071 else if (DECL_P (base
))
2072 return is_global_var (base
);
2073 else if (TREE_CODE (base
) == MEM_REF
2074 || TREE_CODE (base
) == TARGET_MEM_REF
)
2075 return ptr_deref_may_alias_global_p (TREE_OPERAND (base
, 0));
2083 ref_maybe_used_by_stmt_p (gimple
*stmt
, tree ref
, bool tbaa_p
)
2086 ao_ref_init (&r
, ref
);
2087 return ref_maybe_used_by_stmt_p (stmt
, &r
, tbaa_p
);
2090 /* If the call in statement CALL may clobber the memory reference REF
2091 return true, otherwise return false. */
2094 call_may_clobber_ref_p_1 (gcall
*call
, ao_ref
*ref
)
2099 /* If the call is pure or const it cannot clobber anything. */
2100 if (gimple_call_flags (call
)
2101 & (ECF_PURE
|ECF_CONST
|ECF_LOOPING_CONST_OR_PURE
|ECF_NOVOPS
))
2103 if (gimple_call_internal_p (call
))
2104 switch (gimple_call_internal_fn (call
))
2106 /* Treat these internal calls like ECF_PURE for aliasing,
2107 they don't write to any memory the program should care about.
2108 They have important other side-effects, and read memory,
2109 so can't be ECF_NOVOPS. */
2110 case IFN_UBSAN_NULL
:
2111 case IFN_UBSAN_BOUNDS
:
2112 case IFN_UBSAN_VPTR
:
2113 case IFN_UBSAN_OBJECT_SIZE
:
2115 case IFN_ASAN_CHECK
:
2121 base
= ao_ref_base (ref
);
2125 if (TREE_CODE (base
) == SSA_NAME
2126 || CONSTANT_CLASS_P (base
))
2129 /* A call that is not without side-effects might involve volatile
2130 accesses and thus conflicts with all other volatile accesses. */
2131 if (ref
->volatile_p
)
2134 /* If the reference is based on a decl that is not aliased the call
2135 cannot possibly clobber it. */
2137 && !may_be_aliased (base
)
2138 /* But local non-readonly statics can be modified through recursion
2139 or the call may implement a threading barrier which we must
2140 treat as may-def. */
2141 && (TREE_READONLY (base
)
2142 || !is_global_var (base
)))
2145 /* If the reference is based on a pointer that points to memory
2146 that may not be written to then the call cannot possibly clobber it. */
2147 if ((TREE_CODE (base
) == MEM_REF
2148 || TREE_CODE (base
) == TARGET_MEM_REF
)
2149 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
2150 && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base
, 0)))
2153 callee
= gimple_call_fndecl (call
);
2155 /* Handle those builtin functions explicitly that do not act as
2156 escape points. See tree-ssa-structalias.c:find_func_aliases
2157 for the list of builtins we might need to handle here. */
2158 if (callee
!= NULL_TREE
2159 && gimple_call_builtin_p (call
, BUILT_IN_NORMAL
))
2160 switch (DECL_FUNCTION_CODE (callee
))
2162 /* All the following functions clobber memory pointed to by
2163 their first argument. */
2164 case BUILT_IN_STRCPY
:
2165 case BUILT_IN_STRNCPY
:
2166 case BUILT_IN_MEMCPY
:
2167 case BUILT_IN_MEMMOVE
:
2168 case BUILT_IN_MEMPCPY
:
2169 case BUILT_IN_STPCPY
:
2170 case BUILT_IN_STPNCPY
:
2171 case BUILT_IN_STRCAT
:
2172 case BUILT_IN_STRNCAT
:
2173 case BUILT_IN_MEMSET
:
2174 case BUILT_IN_TM_MEMSET
:
2175 CASE_BUILT_IN_TM_STORE (1):
2176 CASE_BUILT_IN_TM_STORE (2):
2177 CASE_BUILT_IN_TM_STORE (4):
2178 CASE_BUILT_IN_TM_STORE (8):
2179 CASE_BUILT_IN_TM_STORE (FLOAT
):
2180 CASE_BUILT_IN_TM_STORE (DOUBLE
):
2181 CASE_BUILT_IN_TM_STORE (LDOUBLE
):
2182 CASE_BUILT_IN_TM_STORE (M64
):
2183 CASE_BUILT_IN_TM_STORE (M128
):
2184 CASE_BUILT_IN_TM_STORE (M256
):
2185 case BUILT_IN_TM_MEMCPY
:
2186 case BUILT_IN_TM_MEMMOVE
:
2189 tree size
= NULL_TREE
;
2190 /* Don't pass in size for strncat, as the maximum size
2191 is strlen (dest) + n + 1 instead of n, resp.
2192 n + 1 at dest + strlen (dest), but strlen (dest) isn't
2194 if (gimple_call_num_args (call
) == 3
2195 && DECL_FUNCTION_CODE (callee
) != BUILT_IN_STRNCAT
)
2196 size
= gimple_call_arg (call
, 2);
2197 ao_ref_init_from_ptr_and_size (&dref
,
2198 gimple_call_arg (call
, 0),
2200 return refs_may_alias_p_1 (&dref
, ref
, false);
2202 case BUILT_IN_STRCPY_CHK
:
2203 case BUILT_IN_STRNCPY_CHK
:
2204 case BUILT_IN_MEMCPY_CHK
:
2205 case BUILT_IN_MEMMOVE_CHK
:
2206 case BUILT_IN_MEMPCPY_CHK
:
2207 case BUILT_IN_STPCPY_CHK
:
2208 case BUILT_IN_STPNCPY_CHK
:
2209 case BUILT_IN_STRCAT_CHK
:
2210 case BUILT_IN_STRNCAT_CHK
:
2211 case BUILT_IN_MEMSET_CHK
:
2214 tree size
= NULL_TREE
;
2215 /* Don't pass in size for __strncat_chk, as the maximum size
2216 is strlen (dest) + n + 1 instead of n, resp.
2217 n + 1 at dest + strlen (dest), but strlen (dest) isn't
2219 if (gimple_call_num_args (call
) == 4
2220 && DECL_FUNCTION_CODE (callee
) != BUILT_IN_STRNCAT_CHK
)
2221 size
= gimple_call_arg (call
, 2);
2222 ao_ref_init_from_ptr_and_size (&dref
,
2223 gimple_call_arg (call
, 0),
2225 return refs_may_alias_p_1 (&dref
, ref
, false);
2227 case BUILT_IN_BCOPY
:
2230 tree size
= gimple_call_arg (call
, 2);
2231 ao_ref_init_from_ptr_and_size (&dref
,
2232 gimple_call_arg (call
, 1),
2234 return refs_may_alias_p_1 (&dref
, ref
, false);
2236 /* Allocating memory does not have any side-effects apart from
2237 being the definition point for the pointer. */
2238 case BUILT_IN_MALLOC
:
2239 case BUILT_IN_ALIGNED_ALLOC
:
2240 case BUILT_IN_CALLOC
:
2241 case BUILT_IN_STRDUP
:
2242 case BUILT_IN_STRNDUP
:
2243 /* Unix98 specifies that errno is set on allocation failure. */
2245 && targetm
.ref_may_alias_errno (ref
))
2248 case BUILT_IN_STACK_SAVE
:
2249 CASE_BUILT_IN_ALLOCA
:
2250 case BUILT_IN_ASSUME_ALIGNED
:
2252 /* But posix_memalign stores a pointer into the memory pointed to
2253 by its first argument. */
2254 case BUILT_IN_POSIX_MEMALIGN
:
2256 tree ptrptr
= gimple_call_arg (call
, 0);
2258 ao_ref_init_from_ptr_and_size (&dref
, ptrptr
,
2259 TYPE_SIZE_UNIT (ptr_type_node
));
2260 return (refs_may_alias_p_1 (&dref
, ref
, false)
2262 && targetm
.ref_may_alias_errno (ref
)));
2264 /* Freeing memory kills the pointed-to memory. More importantly
2265 the call has to serve as a barrier for moving loads and stores
2268 case BUILT_IN_VA_END
:
2270 tree ptr
= gimple_call_arg (call
, 0);
2271 return ptr_deref_may_alias_ref_p_1 (ptr
, ref
);
2273 /* Realloc serves both as allocation point and deallocation point. */
2274 case BUILT_IN_REALLOC
:
2276 tree ptr
= gimple_call_arg (call
, 0);
2277 /* Unix98 specifies that errno is set on allocation failure. */
2278 return ((flag_errno_math
2279 && targetm
.ref_may_alias_errno (ref
))
2280 || ptr_deref_may_alias_ref_p_1 (ptr
, ref
));
2282 case BUILT_IN_GAMMA_R
:
2283 case BUILT_IN_GAMMAF_R
:
2284 case BUILT_IN_GAMMAL_R
:
2285 case BUILT_IN_LGAMMA_R
:
2286 case BUILT_IN_LGAMMAF_R
:
2287 case BUILT_IN_LGAMMAL_R
:
2289 tree out
= gimple_call_arg (call
, 1);
2290 if (ptr_deref_may_alias_ref_p_1 (out
, ref
))
2292 if (flag_errno_math
)
2296 case BUILT_IN_FREXP
:
2297 case BUILT_IN_FREXPF
:
2298 case BUILT_IN_FREXPL
:
2300 case BUILT_IN_MODFF
:
2301 case BUILT_IN_MODFL
:
2303 tree out
= gimple_call_arg (call
, 1);
2304 return ptr_deref_may_alias_ref_p_1 (out
, ref
);
2306 case BUILT_IN_REMQUO
:
2307 case BUILT_IN_REMQUOF
:
2308 case BUILT_IN_REMQUOL
:
2310 tree out
= gimple_call_arg (call
, 2);
2311 if (ptr_deref_may_alias_ref_p_1 (out
, ref
))
2313 if (flag_errno_math
)
2317 case BUILT_IN_SINCOS
:
2318 case BUILT_IN_SINCOSF
:
2319 case BUILT_IN_SINCOSL
:
2321 tree sin
= gimple_call_arg (call
, 1);
2322 tree cos
= gimple_call_arg (call
, 2);
2323 return (ptr_deref_may_alias_ref_p_1 (sin
, ref
)
2324 || ptr_deref_may_alias_ref_p_1 (cos
, ref
));
2326 /* __sync_* builtins and some OpenMP builtins act as threading
2328 #undef DEF_SYNC_BUILTIN
2329 #define DEF_SYNC_BUILTIN(ENUM, NAME, TYPE, ATTRS) case ENUM:
2330 #include "sync-builtins.def"
2331 #undef DEF_SYNC_BUILTIN
2332 case BUILT_IN_GOMP_ATOMIC_START
:
2333 case BUILT_IN_GOMP_ATOMIC_END
:
2334 case BUILT_IN_GOMP_BARRIER
:
2335 case BUILT_IN_GOMP_BARRIER_CANCEL
:
2336 case BUILT_IN_GOMP_TASKWAIT
:
2337 case BUILT_IN_GOMP_TASKGROUP_END
:
2338 case BUILT_IN_GOMP_CRITICAL_START
:
2339 case BUILT_IN_GOMP_CRITICAL_END
:
2340 case BUILT_IN_GOMP_CRITICAL_NAME_START
:
2341 case BUILT_IN_GOMP_CRITICAL_NAME_END
:
2342 case BUILT_IN_GOMP_LOOP_END
:
2343 case BUILT_IN_GOMP_LOOP_END_CANCEL
:
2344 case BUILT_IN_GOMP_ORDERED_START
:
2345 case BUILT_IN_GOMP_ORDERED_END
:
2346 case BUILT_IN_GOMP_SECTIONS_END
:
2347 case BUILT_IN_GOMP_SECTIONS_END_CANCEL
:
2348 case BUILT_IN_GOMP_SINGLE_COPY_START
:
2349 case BUILT_IN_GOMP_SINGLE_COPY_END
:
2352 /* Fallthru to general call handling. */;
2355 /* Check if base is a global static variable that is not written
2357 if (callee
!= NULL_TREE
&& VAR_P (base
) && TREE_STATIC (base
))
2359 struct cgraph_node
*node
= cgraph_node::get (callee
);
2363 && (not_written
= ipa_reference_get_not_written_global (node
))
2364 && bitmap_bit_p (not_written
, ipa_reference_var_uid (base
)))
2368 /* Check if the base variable is call-clobbered. */
2370 return pt_solution_includes (gimple_call_clobber_set (call
), base
);
2371 else if ((TREE_CODE (base
) == MEM_REF
2372 || TREE_CODE (base
) == TARGET_MEM_REF
)
2373 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
)
2375 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (TREE_OPERAND (base
, 0));
2379 return pt_solutions_intersect (gimple_call_clobber_set (call
), &pi
->pt
);
2385 /* If the call in statement CALL may clobber the memory reference REF
2386 return true, otherwise return false. */
2389 call_may_clobber_ref_p (gcall
*call
, tree ref
)
2393 ao_ref_init (&r
, ref
);
2394 res
= call_may_clobber_ref_p_1 (call
, &r
);
2396 ++alias_stats
.call_may_clobber_ref_p_may_alias
;
2398 ++alias_stats
.call_may_clobber_ref_p_no_alias
;
2403 /* If the statement STMT may clobber the memory reference REF return true,
2404 otherwise return false. */
2407 stmt_may_clobber_ref_p_1 (gimple
*stmt
, ao_ref
*ref
, bool tbaa_p
)
2409 if (is_gimple_call (stmt
))
2411 tree lhs
= gimple_call_lhs (stmt
);
2413 && TREE_CODE (lhs
) != SSA_NAME
)
2416 ao_ref_init (&r
, lhs
);
2417 if (refs_may_alias_p_1 (ref
, &r
, tbaa_p
))
2421 return call_may_clobber_ref_p_1 (as_a
<gcall
*> (stmt
), ref
);
2423 else if (gimple_assign_single_p (stmt
))
2425 tree lhs
= gimple_assign_lhs (stmt
);
2426 if (TREE_CODE (lhs
) != SSA_NAME
)
2429 ao_ref_init (&r
, lhs
);
2430 return refs_may_alias_p_1 (ref
, &r
, tbaa_p
);
2433 else if (gimple_code (stmt
) == GIMPLE_ASM
)
2440 stmt_may_clobber_ref_p (gimple
*stmt
, tree ref
, bool tbaa_p
)
2443 ao_ref_init (&r
, ref
);
2444 return stmt_may_clobber_ref_p_1 (stmt
, &r
, tbaa_p
);
2447 /* Return true if store1 and store2 described by corresponding tuples
2448 <BASE, OFFSET, SIZE, MAX_SIZE> have the same size and store to the same
2452 same_addr_size_stores_p (tree base1
, poly_int64 offset1
, poly_int64 size1
,
2453 poly_int64 max_size1
,
2454 tree base2
, poly_int64 offset2
, poly_int64 size2
,
2455 poly_int64 max_size2
)
2457 /* Offsets need to be 0. */
2458 if (maybe_ne (offset1
, 0)
2459 || maybe_ne (offset2
, 0))
2462 bool base1_obj_p
= SSA_VAR_P (base1
);
2463 bool base2_obj_p
= SSA_VAR_P (base2
);
2465 /* We need one object. */
2466 if (base1_obj_p
== base2_obj_p
)
2468 tree obj
= base1_obj_p
? base1
: base2
;
2470 /* And we need one MEM_REF. */
2471 bool base1_memref_p
= TREE_CODE (base1
) == MEM_REF
;
2472 bool base2_memref_p
= TREE_CODE (base2
) == MEM_REF
;
2473 if (base1_memref_p
== base2_memref_p
)
2475 tree memref
= base1_memref_p
? base1
: base2
;
2477 /* Sizes need to be valid. */
2478 if (!known_size_p (max_size1
)
2479 || !known_size_p (max_size2
)
2480 || !known_size_p (size1
)
2481 || !known_size_p (size2
))
2484 /* Max_size needs to match size. */
2485 if (maybe_ne (max_size1
, size1
)
2486 || maybe_ne (max_size2
, size2
))
2489 /* Sizes need to match. */
2490 if (maybe_ne (size1
, size2
))
2494 /* Check that memref is a store to pointer with singleton points-to info. */
2495 if (!integer_zerop (TREE_OPERAND (memref
, 1)))
2497 tree ptr
= TREE_OPERAND (memref
, 0);
2498 if (TREE_CODE (ptr
) != SSA_NAME
)
2500 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (ptr
);
2501 unsigned int pt_uid
;
2503 || !pt_solution_singleton_or_null_p (&pi
->pt
, &pt_uid
))
2506 /* Be conservative with non-call exceptions when the address might
2508 if (cfun
->can_throw_non_call_exceptions
&& pi
->pt
.null
)
2511 /* Check that ptr points relative to obj. */
2512 unsigned int obj_uid
= DECL_PT_UID (obj
);
2513 if (obj_uid
!= pt_uid
)
2516 /* Check that the object size is the same as the store size. That ensures us
2517 that ptr points to the start of obj. */
2518 return (DECL_SIZE (obj
)
2519 && poly_int_tree_p (DECL_SIZE (obj
))
2520 && known_eq (wi::to_poly_offset (DECL_SIZE (obj
)), size1
));
2523 /* If STMT kills the memory reference REF return true, otherwise
2527 stmt_kills_ref_p (gimple
*stmt
, ao_ref
*ref
)
2529 if (!ao_ref_base (ref
))
2532 if (gimple_has_lhs (stmt
)
2533 && TREE_CODE (gimple_get_lhs (stmt
)) != SSA_NAME
2534 /* The assignment is not necessarily carried out if it can throw
2535 and we can catch it in the current function where we could inspect
2537 ??? We only need to care about the RHS throwing. For aggregate
2538 assignments or similar calls and non-call exceptions the LHS
2539 might throw as well. */
2540 && !stmt_can_throw_internal (cfun
, stmt
))
2542 tree lhs
= gimple_get_lhs (stmt
);
2543 /* If LHS is literally a base of the access we are done. */
2546 tree base
= ref
->ref
;
2547 tree innermost_dropped_array_ref
= NULL_TREE
;
2548 if (handled_component_p (base
))
2550 tree saved_lhs0
= NULL_TREE
;
2551 if (handled_component_p (lhs
))
2553 saved_lhs0
= TREE_OPERAND (lhs
, 0);
2554 TREE_OPERAND (lhs
, 0) = integer_zero_node
;
2558 /* Just compare the outermost handled component, if
2559 they are equal we have found a possible common
2561 tree saved_base0
= TREE_OPERAND (base
, 0);
2562 TREE_OPERAND (base
, 0) = integer_zero_node
;
2563 bool res
= operand_equal_p (lhs
, base
, 0);
2564 TREE_OPERAND (base
, 0) = saved_base0
;
2567 /* Remember if we drop an array-ref that we need to
2568 double-check not being at struct end. */
2569 if (TREE_CODE (base
) == ARRAY_REF
2570 || TREE_CODE (base
) == ARRAY_RANGE_REF
)
2571 innermost_dropped_array_ref
= base
;
2572 /* Otherwise drop handled components of the access. */
2575 while (handled_component_p (base
));
2577 TREE_OPERAND (lhs
, 0) = saved_lhs0
;
2579 /* Finally check if the lhs has the same address and size as the
2580 base candidate of the access. Watch out if we have dropped
2581 an array-ref that was at struct end, this means ref->ref may
2582 be outside of the TYPE_SIZE of its base. */
2583 if ((! innermost_dropped_array_ref
2584 || ! array_at_struct_end_p (innermost_dropped_array_ref
))
2586 || (((TYPE_SIZE (TREE_TYPE (lhs
))
2587 == TYPE_SIZE (TREE_TYPE (base
)))
2588 || (TYPE_SIZE (TREE_TYPE (lhs
))
2589 && TYPE_SIZE (TREE_TYPE (base
))
2590 && operand_equal_p (TYPE_SIZE (TREE_TYPE (lhs
)),
2591 TYPE_SIZE (TREE_TYPE (base
)),
2593 && operand_equal_p (lhs
, base
,
2595 | OEP_MATCH_SIDE_EFFECTS
))))
2599 /* Now look for non-literal equal bases with the restriction of
2600 handling constant offset and size. */
2601 /* For a must-alias check we need to be able to constrain
2602 the access properly. */
2603 if (!ref
->max_size_known_p ())
2605 poly_int64 size
, offset
, max_size
, ref_offset
= ref
->offset
;
2607 tree base
= get_ref_base_and_extent (lhs
, &offset
, &size
, &max_size
,
2609 /* We can get MEM[symbol: sZ, index: D.8862_1] here,
2610 so base == ref->base does not always hold. */
2611 if (base
!= ref
->base
)
2613 /* Try using points-to info. */
2614 if (same_addr_size_stores_p (base
, offset
, size
, max_size
, ref
->base
,
2615 ref
->offset
, ref
->size
, ref
->max_size
))
2618 /* If both base and ref->base are MEM_REFs, only compare the
2619 first operand, and if the second operand isn't equal constant,
2620 try to add the offsets into offset and ref_offset. */
2621 if (TREE_CODE (base
) == MEM_REF
&& TREE_CODE (ref
->base
) == MEM_REF
2622 && TREE_OPERAND (base
, 0) == TREE_OPERAND (ref
->base
, 0))
2624 if (!tree_int_cst_equal (TREE_OPERAND (base
, 1),
2625 TREE_OPERAND (ref
->base
, 1)))
2627 poly_offset_int off1
= mem_ref_offset (base
);
2628 off1
<<= LOG2_BITS_PER_UNIT
;
2630 poly_offset_int off2
= mem_ref_offset (ref
->base
);
2631 off2
<<= LOG2_BITS_PER_UNIT
;
2633 if (!off1
.to_shwi (&offset
) || !off2
.to_shwi (&ref_offset
))
2640 /* For a must-alias check we need to be able to constrain
2641 the access properly. */
2642 if (known_eq (size
, max_size
)
2643 && known_subrange_p (ref_offset
, ref
->max_size
, offset
, size
))
2647 if (is_gimple_call (stmt
))
2649 tree callee
= gimple_call_fndecl (stmt
);
2650 if (callee
!= NULL_TREE
2651 && gimple_call_builtin_p (stmt
, BUILT_IN_NORMAL
))
2652 switch (DECL_FUNCTION_CODE (callee
))
2656 tree ptr
= gimple_call_arg (stmt
, 0);
2657 tree base
= ao_ref_base (ref
);
2658 if (base
&& TREE_CODE (base
) == MEM_REF
2659 && TREE_OPERAND (base
, 0) == ptr
)
2664 case BUILT_IN_MEMCPY
:
2665 case BUILT_IN_MEMPCPY
:
2666 case BUILT_IN_MEMMOVE
:
2667 case BUILT_IN_MEMSET
:
2668 case BUILT_IN_MEMCPY_CHK
:
2669 case BUILT_IN_MEMPCPY_CHK
:
2670 case BUILT_IN_MEMMOVE_CHK
:
2671 case BUILT_IN_MEMSET_CHK
:
2672 case BUILT_IN_STRNCPY
:
2673 case BUILT_IN_STPNCPY
:
2675 /* For a must-alias check we need to be able to constrain
2676 the access properly. */
2677 if (!ref
->max_size_known_p ())
2679 tree dest
= gimple_call_arg (stmt
, 0);
2680 tree len
= gimple_call_arg (stmt
, 2);
2681 if (!poly_int_tree_p (len
))
2683 tree rbase
= ref
->base
;
2684 poly_offset_int roffset
= ref
->offset
;
2686 ao_ref_init_from_ptr_and_size (&dref
, dest
, len
);
2687 tree base
= ao_ref_base (&dref
);
2688 poly_offset_int offset
= dref
.offset
;
2689 if (!base
|| !known_size_p (dref
.size
))
2691 if (TREE_CODE (base
) == MEM_REF
)
2693 if (TREE_CODE (rbase
) != MEM_REF
)
2695 // Compare pointers.
2696 offset
+= mem_ref_offset (base
) << LOG2_BITS_PER_UNIT
;
2697 roffset
+= mem_ref_offset (rbase
) << LOG2_BITS_PER_UNIT
;
2698 base
= TREE_OPERAND (base
, 0);
2699 rbase
= TREE_OPERAND (rbase
, 0);
2702 && known_subrange_p (roffset
, ref
->max_size
, offset
,
2703 wi::to_poly_offset (len
)
2704 << LOG2_BITS_PER_UNIT
))
2709 case BUILT_IN_VA_END
:
2711 tree ptr
= gimple_call_arg (stmt
, 0);
2712 if (TREE_CODE (ptr
) == ADDR_EXPR
)
2714 tree base
= ao_ref_base (ref
);
2715 if (TREE_OPERAND (ptr
, 0) == base
)
2728 stmt_kills_ref_p (gimple
*stmt
, tree ref
)
2731 ao_ref_init (&r
, ref
);
2732 return stmt_kills_ref_p (stmt
, &r
);
2736 /* Walk the virtual use-def chain of VUSE until hitting the virtual operand
2737 TARGET or a statement clobbering the memory reference REF in which
2738 case false is returned. The walk starts with VUSE, one argument of PHI. */
2741 maybe_skip_until (gimple
*phi
, tree
&target
, basic_block target_bb
,
2742 ao_ref
*ref
, tree vuse
, unsigned int &limit
, bitmap
*visited
,
2743 bool abort_on_visited
,
2744 void *(*translate
)(ao_ref
*, tree
, void *, bool *),
2747 basic_block bb
= gimple_bb (phi
);
2750 *visited
= BITMAP_ALLOC (NULL
);
2752 bitmap_set_bit (*visited
, SSA_NAME_VERSION (PHI_RESULT (phi
)));
2754 /* Walk until we hit the target. */
2755 while (vuse
!= target
)
2757 gimple
*def_stmt
= SSA_NAME_DEF_STMT (vuse
);
2758 /* If we are searching for the target VUSE by walking up to
2759 TARGET_BB dominating the original PHI we are finished once
2760 we reach a default def or a definition in a block dominating
2761 that block. Update TARGET and return. */
2763 && (gimple_nop_p (def_stmt
)
2764 || dominated_by_p (CDI_DOMINATORS
,
2765 target_bb
, gimple_bb (def_stmt
))))
2771 /* Recurse for PHI nodes. */
2772 if (gimple_code (def_stmt
) == GIMPLE_PHI
)
2774 /* An already visited PHI node ends the walk successfully. */
2775 if (bitmap_bit_p (*visited
, SSA_NAME_VERSION (PHI_RESULT (def_stmt
))))
2776 return !abort_on_visited
;
2777 vuse
= get_continuation_for_phi (def_stmt
, ref
, limit
,
2778 visited
, abort_on_visited
,
2784 else if (gimple_nop_p (def_stmt
))
2788 /* A clobbering statement or the end of the IL ends it failing. */
2789 if ((int)limit
<= 0)
2792 if (stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
2794 bool disambiguate_only
= true;
2796 && (*translate
) (ref
, vuse
, data
, &disambiguate_only
) == NULL
)
2802 /* If we reach a new basic-block see if we already skipped it
2803 in a previous walk that ended successfully. */
2804 if (gimple_bb (def_stmt
) != bb
)
2806 if (!bitmap_set_bit (*visited
, SSA_NAME_VERSION (vuse
)))
2807 return !abort_on_visited
;
2808 bb
= gimple_bb (def_stmt
);
2810 vuse
= gimple_vuse (def_stmt
);
2816 /* Starting from a PHI node for the virtual operand of the memory reference
2817 REF find a continuation virtual operand that allows to continue walking
2818 statements dominating PHI skipping only statements that cannot possibly
2819 clobber REF. Decrements LIMIT for each alias disambiguation done
2820 and aborts the walk, returning NULL_TREE if it reaches zero.
2821 Returns NULL_TREE if no suitable virtual operand can be found. */
2824 get_continuation_for_phi (gimple
*phi
, ao_ref
*ref
,
2825 unsigned int &limit
, bitmap
*visited
,
2826 bool abort_on_visited
,
2827 void *(*translate
)(ao_ref
*, tree
, void *, bool *),
2830 unsigned nargs
= gimple_phi_num_args (phi
);
2832 /* Through a single-argument PHI we can simply look through. */
2834 return PHI_ARG_DEF (phi
, 0);
2836 /* For two or more arguments try to pairwise skip non-aliasing code
2837 until we hit the phi argument definition that dominates the other one. */
2838 basic_block phi_bb
= gimple_bb (phi
);
2842 /* Find a candidate for the virtual operand which definition
2843 dominates those of all others. */
2844 /* First look if any of the args themselves satisfy this. */
2845 for (i
= 0; i
< nargs
; ++i
)
2847 arg0
= PHI_ARG_DEF (phi
, i
);
2848 if (SSA_NAME_IS_DEFAULT_DEF (arg0
))
2850 basic_block def_bb
= gimple_bb (SSA_NAME_DEF_STMT (arg0
));
2851 if (def_bb
!= phi_bb
2852 && dominated_by_p (CDI_DOMINATORS
, phi_bb
, def_bb
))
2856 /* If not, look if we can reach such candidate by walking defs
2857 until we hit the immediate dominator. maybe_skip_until will
2859 basic_block dom
= get_immediate_dominator (CDI_DOMINATORS
, phi_bb
);
2861 /* Then check against the (to be) found candidate. */
2862 for (i
= 0; i
< nargs
; ++i
)
2864 arg1
= PHI_ARG_DEF (phi
, i
);
2867 else if (! maybe_skip_until (phi
, arg0
, dom
, ref
, arg1
, limit
, visited
,
2869 /* Do not translate when walking over
2873 gimple_bb (SSA_NAME_DEF_STMT (arg1
)),
2875 ? NULL
: translate
, data
))
2882 /* Based on the memory reference REF and its virtual use VUSE call
2883 WALKER for each virtual use that is equivalent to VUSE, including VUSE
2884 itself. That is, for each virtual use for which its defining statement
2885 does not clobber REF.
2887 WALKER is called with REF, the current virtual use and DATA. If
2888 WALKER returns non-NULL the walk stops and its result is returned.
2889 At the end of a non-successful walk NULL is returned.
2891 TRANSLATE if non-NULL is called with a pointer to REF, the virtual
2892 use which definition is a statement that may clobber REF and DATA.
2893 If TRANSLATE returns (void *)-1 the walk stops and NULL is returned.
2894 If TRANSLATE returns non-NULL the walk stops and its result is returned.
2895 If TRANSLATE returns NULL the walk continues and TRANSLATE is supposed
2896 to adjust REF and *DATA to make that valid.
2898 VALUEIZE if non-NULL is called with the next VUSE that is considered
2899 and return value is substituted for that. This can be used to
2900 implement optimistic value-numbering for example. Note that the
2901 VUSE argument is assumed to be valueized already.
2903 LIMIT specifies the number of alias queries we are allowed to do,
2904 the walk stops when it reaches zero and NULL is returned. LIMIT
2905 is decremented by the number of alias queries (plus adjustments
2906 done by the callbacks) upon return.
2908 TODO: Cache the vector of equivalent vuses per ref, vuse pair. */
2911 walk_non_aliased_vuses (ao_ref
*ref
, tree vuse
,
2912 void *(*walker
)(ao_ref
*, tree
, void *),
2913 void *(*translate
)(ao_ref
*, tree
, void *, bool *),
2914 tree (*valueize
)(tree
),
2915 unsigned &limit
, void *data
)
2917 bitmap visited
= NULL
;
2919 bool translated
= false;
2921 timevar_push (TV_ALIAS_STMT_WALK
);
2927 /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */
2928 res
= (*walker
) (ref
, vuse
, data
);
2930 if (res
== (void *)-1)
2935 /* Lookup succeeded. */
2936 else if (res
!= NULL
)
2941 vuse
= valueize (vuse
);
2948 def_stmt
= SSA_NAME_DEF_STMT (vuse
);
2949 if (gimple_nop_p (def_stmt
))
2951 else if (gimple_code (def_stmt
) == GIMPLE_PHI
)
2952 vuse
= get_continuation_for_phi (def_stmt
, ref
, limit
,
2953 &visited
, translated
, translate
, data
);
2956 if ((int)limit
<= 0)
2961 if (stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
2965 bool disambiguate_only
= false;
2966 res
= (*translate
) (ref
, vuse
, data
, &disambiguate_only
);
2967 /* Failed lookup and translation. */
2968 if (res
== (void *)-1)
2973 /* Lookup succeeded. */
2974 else if (res
!= NULL
)
2976 /* Translation succeeded, continue walking. */
2977 translated
= translated
|| !disambiguate_only
;
2979 vuse
= gimple_vuse (def_stmt
);
2985 BITMAP_FREE (visited
);
2987 timevar_pop (TV_ALIAS_STMT_WALK
);
2993 /* Based on the memory reference REF call WALKER for each vdef which
2994 defining statement may clobber REF, starting with VDEF. If REF
2995 is NULL_TREE, each defining statement is visited.
2997 WALKER is called with REF, the current vdef and DATA. If WALKER
2998 returns true the walk is stopped, otherwise it continues.
3000 If function entry is reached, FUNCTION_ENTRY_REACHED is set to true.
3001 The pointer may be NULL and then we do not track this information.
3003 At PHI nodes walk_aliased_vdefs forks into one walk for reach
3004 PHI argument (but only one walk continues on merge points), the
3005 return value is true if any of the walks was successful.
3007 The function returns the number of statements walked or -1 if
3008 LIMIT stmts were walked and the walk was aborted at this point.
3009 If LIMIT is zero the walk is not aborted. */
3012 walk_aliased_vdefs_1 (ao_ref
*ref
, tree vdef
,
3013 bool (*walker
)(ao_ref
*, tree
, void *), void *data
,
3014 bitmap
*visited
, unsigned int cnt
,
3015 bool *function_entry_reached
, unsigned limit
)
3019 gimple
*def_stmt
= SSA_NAME_DEF_STMT (vdef
);
3022 && !bitmap_set_bit (*visited
, SSA_NAME_VERSION (vdef
)))
3025 if (gimple_nop_p (def_stmt
))
3027 if (function_entry_reached
)
3028 *function_entry_reached
= true;
3031 else if (gimple_code (def_stmt
) == GIMPLE_PHI
)
3035 *visited
= BITMAP_ALLOC (NULL
);
3036 for (i
= 0; i
< gimple_phi_num_args (def_stmt
); ++i
)
3038 int res
= walk_aliased_vdefs_1 (ref
,
3039 gimple_phi_arg_def (def_stmt
, i
),
3040 walker
, data
, visited
, cnt
,
3041 function_entry_reached
, limit
);
3049 /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */
3054 || stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
3055 && (*walker
) (ref
, vdef
, data
))
3058 vdef
= gimple_vuse (def_stmt
);
3064 walk_aliased_vdefs (ao_ref
*ref
, tree vdef
,
3065 bool (*walker
)(ao_ref
*, tree
, void *), void *data
,
3067 bool *function_entry_reached
, unsigned int limit
)
3069 bitmap local_visited
= NULL
;
3072 timevar_push (TV_ALIAS_STMT_WALK
);
3074 if (function_entry_reached
)
3075 *function_entry_reached
= false;
3077 ret
= walk_aliased_vdefs_1 (ref
, vdef
, walker
, data
,
3078 visited
? visited
: &local_visited
, 0,
3079 function_entry_reached
, limit
);
3081 BITMAP_FREE (local_visited
);
3083 timevar_pop (TV_ALIAS_STMT_WALK
);