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)))
1018 ref1
= TREE_OPERAND (TREE_OPERAND (ref1
, 0), 0);
1021 /* Create the stack of handled components for REF2. */
1022 while (handled_component_p (ref2
))
1024 component_refs2
.safe_push (ref2
);
1025 ref2
= TREE_OPERAND (ref2
, 0);
1027 if (TREE_CODE (ref2
) == MEM_REF
)
1029 if (!integer_zerop (TREE_OPERAND (ref2
, 1)))
1031 ref2
= TREE_OPERAND (TREE_OPERAND (ref2
, 0), 0);
1034 /* Bases must be either same or uncomparable. */
1035 gcc_checking_assert (ref1
== ref2
1036 || (DECL_P (ref1
) && DECL_P (ref2
)
1037 && compare_base_decls (ref1
, ref2
) != 0));
1039 /* Pop the stacks in parallel and examine the COMPONENT_REFs of the same
1040 rank. This is sufficient because we start from the same DECL and you
1041 cannot reference several fields at a time with COMPONENT_REFs (unlike
1042 with ARRAY_RANGE_REFs for arrays) so you always need the same number
1043 of them to access a sub-component, unless you're in a union, in which
1044 case the return value will precisely be false. */
1049 if (component_refs1
.is_empty ())
1051 ref1
= component_refs1
.pop ();
1053 while (!RECORD_OR_UNION_TYPE_P (TREE_TYPE (TREE_OPERAND (ref1
, 0))));
1057 if (component_refs2
.is_empty ())
1059 ref2
= component_refs2
.pop ();
1061 while (!RECORD_OR_UNION_TYPE_P (TREE_TYPE (TREE_OPERAND (ref2
, 0))));
1063 /* Beware of BIT_FIELD_REF. */
1064 if (TREE_CODE (ref1
) != COMPONENT_REF
1065 || TREE_CODE (ref2
) != COMPONENT_REF
)
1068 tree field1
= TREE_OPERAND (ref1
, 1);
1069 tree field2
= TREE_OPERAND (ref2
, 1);
1071 /* ??? We cannot simply use the type of operand #0 of the refs here
1072 as the Fortran compiler smuggles type punning into COMPONENT_REFs
1073 for common blocks instead of using unions like everyone else. */
1074 tree type1
= DECL_CONTEXT (field1
);
1075 tree type2
= DECL_CONTEXT (field2
);
1077 /* We cannot disambiguate fields in a union or qualified union. */
1078 if (type1
!= type2
|| TREE_CODE (type1
) != RECORD_TYPE
)
1081 if (field1
!= field2
)
1083 /* A field and its representative need to be considered the
1085 if (DECL_BIT_FIELD_REPRESENTATIVE (field1
) == field2
1086 || DECL_BIT_FIELD_REPRESENTATIVE (field2
) == field1
)
1088 /* Different fields of the same record type cannot overlap.
1089 ??? Bitfields can overlap at RTL level so punt on them. */
1090 if (DECL_BIT_FIELD (field1
) && DECL_BIT_FIELD (field2
))
1099 /* qsort compare function to sort FIELD_DECLs after their
1100 DECL_FIELD_CONTEXT TYPE_UID. */
1103 ncr_compar (const void *field1_
, const void *field2_
)
1105 const_tree field1
= *(const_tree
*) const_cast <void *>(field1_
);
1106 const_tree field2
= *(const_tree
*) const_cast <void *>(field2_
);
1107 unsigned int uid1
= TYPE_UID (DECL_FIELD_CONTEXT (field1
));
1108 unsigned int uid2
= TYPE_UID (DECL_FIELD_CONTEXT (field2
));
1111 else if (uid1
> uid2
)
1116 /* Return true if we can determine that the fields referenced cannot
1117 overlap for any pair of objects. */
1120 nonoverlapping_component_refs_p (const_tree x
, const_tree y
)
1122 if (!flag_strict_aliasing
1124 || TREE_CODE (x
) != COMPONENT_REF
1125 || TREE_CODE (y
) != COMPONENT_REF
)
1128 auto_vec
<const_tree
, 16> fieldsx
;
1129 while (TREE_CODE (x
) == COMPONENT_REF
)
1131 tree field
= TREE_OPERAND (x
, 1);
1132 tree type
= DECL_FIELD_CONTEXT (field
);
1133 if (TREE_CODE (type
) == RECORD_TYPE
)
1134 fieldsx
.safe_push (field
);
1135 x
= TREE_OPERAND (x
, 0);
1137 if (fieldsx
.length () == 0)
1139 auto_vec
<const_tree
, 16> fieldsy
;
1140 while (TREE_CODE (y
) == COMPONENT_REF
)
1142 tree field
= TREE_OPERAND (y
, 1);
1143 tree type
= DECL_FIELD_CONTEXT (field
);
1144 if (TREE_CODE (type
) == RECORD_TYPE
)
1145 fieldsy
.safe_push (TREE_OPERAND (y
, 1));
1146 y
= TREE_OPERAND (y
, 0);
1148 if (fieldsy
.length () == 0)
1151 /* Most common case first. */
1152 if (fieldsx
.length () == 1
1153 && fieldsy
.length () == 1)
1154 return ((DECL_FIELD_CONTEXT (fieldsx
[0])
1155 == DECL_FIELD_CONTEXT (fieldsy
[0]))
1156 && fieldsx
[0] != fieldsy
[0]
1157 && !(DECL_BIT_FIELD (fieldsx
[0]) && DECL_BIT_FIELD (fieldsy
[0])));
1159 if (fieldsx
.length () == 2)
1161 if (ncr_compar (&fieldsx
[0], &fieldsx
[1]) == 1)
1162 std::swap (fieldsx
[0], fieldsx
[1]);
1165 fieldsx
.qsort (ncr_compar
);
1167 if (fieldsy
.length () == 2)
1169 if (ncr_compar (&fieldsy
[0], &fieldsy
[1]) == 1)
1170 std::swap (fieldsy
[0], fieldsy
[1]);
1173 fieldsy
.qsort (ncr_compar
);
1175 unsigned i
= 0, j
= 0;
1178 const_tree fieldx
= fieldsx
[i
];
1179 const_tree fieldy
= fieldsy
[j
];
1180 tree typex
= DECL_FIELD_CONTEXT (fieldx
);
1181 tree typey
= DECL_FIELD_CONTEXT (fieldy
);
1184 /* We're left with accessing different fields of a structure,
1185 no possible overlap. */
1186 if (fieldx
!= fieldy
)
1188 /* A field and its representative need to be considered the
1190 if (DECL_BIT_FIELD_REPRESENTATIVE (fieldx
) == fieldy
1191 || DECL_BIT_FIELD_REPRESENTATIVE (fieldy
) == fieldx
)
1193 /* Different fields of the same record type cannot overlap.
1194 ??? Bitfields can overlap at RTL level so punt on them. */
1195 if (DECL_BIT_FIELD (fieldx
) && DECL_BIT_FIELD (fieldy
))
1200 if (TYPE_UID (typex
) < TYPE_UID (typey
))
1203 if (i
== fieldsx
.length ())
1209 if (j
== fieldsy
.length ())
1219 /* Return true if two memory references based on the variables BASE1
1220 and BASE2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and
1221 [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. REF1 and REF2
1222 if non-NULL are the complete memory reference trees. */
1225 decl_refs_may_alias_p (tree ref1
, tree base1
,
1226 poly_int64 offset1
, poly_int64 max_size1
,
1227 tree ref2
, tree base2
,
1228 poly_int64 offset2
, poly_int64 max_size2
)
1230 gcc_checking_assert (DECL_P (base1
) && DECL_P (base2
));
1232 /* If both references are based on different variables, they cannot alias. */
1233 if (compare_base_decls (base1
, base2
) == 0)
1236 /* If both references are based on the same variable, they cannot alias if
1237 the accesses do not overlap. */
1238 if (!ranges_maybe_overlap_p (offset1
, max_size1
, offset2
, max_size2
))
1241 /* For components with variable position, the above test isn't sufficient,
1242 so we disambiguate component references manually. */
1244 && handled_component_p (ref1
) && handled_component_p (ref2
)
1245 && nonoverlapping_component_refs_of_decl_p (ref1
, ref2
))
1251 /* Return true if an indirect reference based on *PTR1 constrained
1252 to [OFFSET1, OFFSET1 + MAX_SIZE1) may alias a variable based on BASE2
1253 constrained to [OFFSET2, OFFSET2 + MAX_SIZE2). *PTR1 and BASE2 have
1254 the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1
1255 in which case they are computed on-demand. REF1 and REF2
1256 if non-NULL are the complete memory reference trees. */
1259 indirect_ref_may_alias_decl_p (tree ref1 ATTRIBUTE_UNUSED
, tree base1
,
1260 poly_int64 offset1
, poly_int64 max_size1
,
1261 alias_set_type ref1_alias_set
,
1262 alias_set_type base1_alias_set
,
1263 tree ref2 ATTRIBUTE_UNUSED
, tree base2
,
1264 poly_int64 offset2
, poly_int64 max_size2
,
1265 alias_set_type ref2_alias_set
,
1266 alias_set_type base2_alias_set
, bool tbaa_p
)
1269 tree ptrtype1
, dbase2
;
1271 gcc_checking_assert ((TREE_CODE (base1
) == MEM_REF
1272 || TREE_CODE (base1
) == TARGET_MEM_REF
)
1275 ptr1
= TREE_OPERAND (base1
, 0);
1276 poly_offset_int moff
= mem_ref_offset (base1
) << LOG2_BITS_PER_UNIT
;
1278 /* If only one reference is based on a variable, they cannot alias if
1279 the pointer access is beyond the extent of the variable access.
1280 (the pointer base cannot validly point to an offset less than zero
1282 ??? IVOPTs creates bases that do not honor this restriction,
1283 so do not apply this optimization for TARGET_MEM_REFs. */
1284 if (TREE_CODE (base1
) != TARGET_MEM_REF
1285 && !ranges_maybe_overlap_p (offset1
+ moff
, -1, offset2
, max_size2
))
1287 /* They also cannot alias if the pointer may not point to the decl. */
1288 if (!ptr_deref_may_alias_decl_p (ptr1
, base2
))
1291 /* Disambiguations that rely on strict aliasing rules follow. */
1292 if (!flag_strict_aliasing
|| !tbaa_p
)
1295 ptrtype1
= TREE_TYPE (TREE_OPERAND (base1
, 1));
1297 /* If the alias set for a pointer access is zero all bets are off. */
1298 if (base1_alias_set
== 0)
1301 /* When we are trying to disambiguate an access with a pointer dereference
1302 as base versus one with a decl as base we can use both the size
1303 of the decl and its dynamic type for extra disambiguation.
1304 ??? We do not know anything about the dynamic type of the decl
1305 other than that its alias-set contains base2_alias_set as a subset
1306 which does not help us here. */
1307 /* As we know nothing useful about the dynamic type of the decl just
1308 use the usual conflict check rather than a subset test.
1309 ??? We could introduce -fvery-strict-aliasing when the language
1310 does not allow decls to have a dynamic type that differs from their
1311 static type. Then we can check
1312 !alias_set_subset_of (base1_alias_set, base2_alias_set) instead. */
1313 if (base1_alias_set
!= base2_alias_set
1314 && !alias_sets_conflict_p (base1_alias_set
, base2_alias_set
))
1316 /* If the size of the access relevant for TBAA through the pointer
1317 is bigger than the size of the decl we can't possibly access the
1318 decl via that pointer. */
1319 if (/* ??? This in turn may run afoul when a decl of type T which is
1320 a member of union type U is accessed through a pointer to
1321 type U and sizeof T is smaller than sizeof U. */
1322 TREE_CODE (TREE_TYPE (ptrtype1
)) != UNION_TYPE
1323 && TREE_CODE (TREE_TYPE (ptrtype1
)) != QUAL_UNION_TYPE
1324 && compare_sizes (DECL_SIZE (base2
),
1325 TYPE_SIZE (TREE_TYPE (ptrtype1
))) < 0)
1331 /* If the decl is accessed via a MEM_REF, reconstruct the base
1332 we can use for TBAA and an appropriately adjusted offset. */
1334 while (handled_component_p (dbase2
))
1335 dbase2
= TREE_OPERAND (dbase2
, 0);
1336 poly_int64 doffset1
= offset1
;
1337 poly_offset_int doffset2
= offset2
;
1338 if (TREE_CODE (dbase2
) == MEM_REF
1339 || TREE_CODE (dbase2
) == TARGET_MEM_REF
)
1340 doffset2
-= mem_ref_offset (dbase2
) << LOG2_BITS_PER_UNIT
;
1342 /* If either reference is view-converted, give up now. */
1343 if (same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (ptrtype1
)) != 1
1344 || same_type_for_tbaa (TREE_TYPE (dbase2
), TREE_TYPE (base2
)) != 1)
1347 /* If both references are through the same type, they do not alias
1348 if the accesses do not overlap. This does extra disambiguation
1349 for mixed/pointer accesses but requires strict aliasing.
1350 For MEM_REFs we require that the component-ref offset we computed
1351 is relative to the start of the type which we ensure by
1352 comparing rvalue and access type and disregarding the constant
1354 if ((TREE_CODE (base1
) != TARGET_MEM_REF
1355 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1356 && same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (dbase2
)) == 1)
1357 return ranges_maybe_overlap_p (doffset1
, max_size1
, doffset2
, max_size2
);
1360 && nonoverlapping_component_refs_p (ref1
, ref2
))
1363 /* Do access-path based disambiguation. */
1365 && (handled_component_p (ref1
) || handled_component_p (ref2
)))
1366 return aliasing_component_refs_p (ref1
,
1367 ref1_alias_set
, base1_alias_set
,
1370 ref2_alias_set
, base2_alias_set
,
1371 offset2
, max_size2
, true);
1376 /* Return true if two indirect references based on *PTR1
1377 and *PTR2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and
1378 [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. *PTR1 and *PTR2 have
1379 the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1
1380 in which case they are computed on-demand. REF1 and REF2
1381 if non-NULL are the complete memory reference trees. */
1384 indirect_refs_may_alias_p (tree ref1 ATTRIBUTE_UNUSED
, tree base1
,
1385 poly_int64 offset1
, poly_int64 max_size1
,
1386 alias_set_type ref1_alias_set
,
1387 alias_set_type base1_alias_set
,
1388 tree ref2 ATTRIBUTE_UNUSED
, tree base2
,
1389 poly_int64 offset2
, poly_int64 max_size2
,
1390 alias_set_type ref2_alias_set
,
1391 alias_set_type base2_alias_set
, bool tbaa_p
)
1395 tree ptrtype1
, ptrtype2
;
1397 gcc_checking_assert ((TREE_CODE (base1
) == MEM_REF
1398 || TREE_CODE (base1
) == TARGET_MEM_REF
)
1399 && (TREE_CODE (base2
) == MEM_REF
1400 || TREE_CODE (base2
) == TARGET_MEM_REF
));
1402 ptr1
= TREE_OPERAND (base1
, 0);
1403 ptr2
= TREE_OPERAND (base2
, 0);
1405 /* If both bases are based on pointers they cannot alias if they may not
1406 point to the same memory object or if they point to the same object
1407 and the accesses do not overlap. */
1408 if ((!cfun
|| gimple_in_ssa_p (cfun
))
1409 && operand_equal_p (ptr1
, ptr2
, 0)
1410 && (((TREE_CODE (base1
) != TARGET_MEM_REF
1411 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1412 && (TREE_CODE (base2
) != TARGET_MEM_REF
1413 || (!TMR_INDEX (base2
) && !TMR_INDEX2 (base2
))))
1414 || (TREE_CODE (base1
) == TARGET_MEM_REF
1415 && TREE_CODE (base2
) == TARGET_MEM_REF
1416 && (TMR_STEP (base1
) == TMR_STEP (base2
)
1417 || (TMR_STEP (base1
) && TMR_STEP (base2
)
1418 && operand_equal_p (TMR_STEP (base1
),
1419 TMR_STEP (base2
), 0)))
1420 && (TMR_INDEX (base1
) == TMR_INDEX (base2
)
1421 || (TMR_INDEX (base1
) && TMR_INDEX (base2
)
1422 && operand_equal_p (TMR_INDEX (base1
),
1423 TMR_INDEX (base2
), 0)))
1424 && (TMR_INDEX2 (base1
) == TMR_INDEX2 (base2
)
1425 || (TMR_INDEX2 (base1
) && TMR_INDEX2 (base2
)
1426 && operand_equal_p (TMR_INDEX2 (base1
),
1427 TMR_INDEX2 (base2
), 0))))))
1429 poly_offset_int moff1
= mem_ref_offset (base1
) << LOG2_BITS_PER_UNIT
;
1430 poly_offset_int moff2
= mem_ref_offset (base2
) << LOG2_BITS_PER_UNIT
;
1431 return ranges_maybe_overlap_p (offset1
+ moff1
, max_size1
,
1432 offset2
+ moff2
, max_size2
);
1434 if (!ptr_derefs_may_alias_p (ptr1
, ptr2
))
1437 /* Disambiguations that rely on strict aliasing rules follow. */
1438 if (!flag_strict_aliasing
|| !tbaa_p
)
1441 ptrtype1
= TREE_TYPE (TREE_OPERAND (base1
, 1));
1442 ptrtype2
= TREE_TYPE (TREE_OPERAND (base2
, 1));
1444 /* If the alias set for a pointer access is zero all bets are off. */
1445 if (base1_alias_set
== 0
1446 || base2_alias_set
== 0)
1449 /* If both references are through the same type, they do not alias
1450 if the accesses do not overlap. This does extra disambiguation
1451 for mixed/pointer accesses but requires strict aliasing. */
1452 if ((TREE_CODE (base1
) != TARGET_MEM_REF
1453 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1454 && (TREE_CODE (base2
) != TARGET_MEM_REF
1455 || (!TMR_INDEX (base2
) && !TMR_INDEX2 (base2
)))
1456 && same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (ptrtype1
)) == 1
1457 && same_type_for_tbaa (TREE_TYPE (base2
), TREE_TYPE (ptrtype2
)) == 1
1458 && same_type_for_tbaa (TREE_TYPE (ptrtype1
),
1459 TREE_TYPE (ptrtype2
)) == 1
1460 /* But avoid treating arrays as "objects", instead assume they
1461 can overlap by an exact multiple of their element size. */
1462 && TREE_CODE (TREE_TYPE (ptrtype1
)) != ARRAY_TYPE
)
1463 return ranges_maybe_overlap_p (offset1
, max_size1
, offset2
, max_size2
);
1465 /* Do type-based disambiguation. */
1466 if (base1_alias_set
!= base2_alias_set
1467 && !alias_sets_conflict_p (base1_alias_set
, base2_alias_set
))
1470 /* If either reference is view-converted, give up now. */
1471 if (same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (ptrtype1
)) != 1
1472 || same_type_for_tbaa (TREE_TYPE (base2
), TREE_TYPE (ptrtype2
)) != 1)
1476 && nonoverlapping_component_refs_p (ref1
, ref2
))
1479 /* Do access-path based disambiguation. */
1481 && (handled_component_p (ref1
) || handled_component_p (ref2
)))
1482 return aliasing_component_refs_p (ref1
,
1483 ref1_alias_set
, base1_alias_set
,
1486 ref2_alias_set
, base2_alias_set
,
1487 offset2
, max_size2
, false);
1492 /* Return true, if the two memory references REF1 and REF2 may alias. */
1495 refs_may_alias_p_2 (ao_ref
*ref1
, ao_ref
*ref2
, bool tbaa_p
)
1498 poly_int64 offset1
= 0, offset2
= 0;
1499 poly_int64 max_size1
= -1, max_size2
= -1;
1500 bool var1_p
, var2_p
, ind1_p
, ind2_p
;
1502 gcc_checking_assert ((!ref1
->ref
1503 || TREE_CODE (ref1
->ref
) == SSA_NAME
1504 || DECL_P (ref1
->ref
)
1505 || TREE_CODE (ref1
->ref
) == STRING_CST
1506 || handled_component_p (ref1
->ref
)
1507 || TREE_CODE (ref1
->ref
) == MEM_REF
1508 || TREE_CODE (ref1
->ref
) == TARGET_MEM_REF
)
1510 || TREE_CODE (ref2
->ref
) == SSA_NAME
1511 || DECL_P (ref2
->ref
)
1512 || TREE_CODE (ref2
->ref
) == STRING_CST
1513 || handled_component_p (ref2
->ref
)
1514 || TREE_CODE (ref2
->ref
) == MEM_REF
1515 || TREE_CODE (ref2
->ref
) == TARGET_MEM_REF
));
1517 /* Decompose the references into their base objects and the access. */
1518 base1
= ao_ref_base (ref1
);
1519 offset1
= ref1
->offset
;
1520 max_size1
= ref1
->max_size
;
1521 base2
= ao_ref_base (ref2
);
1522 offset2
= ref2
->offset
;
1523 max_size2
= ref2
->max_size
;
1525 /* We can end up with registers or constants as bases for example from
1526 *D.1663_44 = VIEW_CONVERT_EXPR<struct DB_LSN>(__tmp$B0F64_59);
1527 which is seen as a struct copy. */
1528 if (TREE_CODE (base1
) == SSA_NAME
1529 || TREE_CODE (base1
) == CONST_DECL
1530 || TREE_CODE (base1
) == CONSTRUCTOR
1531 || TREE_CODE (base1
) == ADDR_EXPR
1532 || CONSTANT_CLASS_P (base1
)
1533 || TREE_CODE (base2
) == SSA_NAME
1534 || TREE_CODE (base2
) == CONST_DECL
1535 || TREE_CODE (base2
) == CONSTRUCTOR
1536 || TREE_CODE (base2
) == ADDR_EXPR
1537 || CONSTANT_CLASS_P (base2
))
1540 /* We can end up referring to code via function and label decls.
1541 As we likely do not properly track code aliases conservatively
1543 if (TREE_CODE (base1
) == FUNCTION_DECL
1544 || TREE_CODE (base1
) == LABEL_DECL
1545 || TREE_CODE (base2
) == FUNCTION_DECL
1546 || TREE_CODE (base2
) == LABEL_DECL
)
1549 /* Two volatile accesses always conflict. */
1550 if (ref1
->volatile_p
1551 && ref2
->volatile_p
)
1554 /* Defer to simple offset based disambiguation if we have
1555 references based on two decls. Do this before defering to
1556 TBAA to handle must-alias cases in conformance with the
1557 GCC extension of allowing type-punning through unions. */
1558 var1_p
= DECL_P (base1
);
1559 var2_p
= DECL_P (base2
);
1560 if (var1_p
&& var2_p
)
1561 return decl_refs_may_alias_p (ref1
->ref
, base1
, offset1
, max_size1
,
1562 ref2
->ref
, base2
, offset2
, max_size2
);
1564 /* Handle restrict based accesses.
1565 ??? ao_ref_base strips inner MEM_REF [&decl], recover from that
1567 tree rbase1
= base1
;
1568 tree rbase2
= base2
;
1573 while (handled_component_p (rbase1
))
1574 rbase1
= TREE_OPERAND (rbase1
, 0);
1580 while (handled_component_p (rbase2
))
1581 rbase2
= TREE_OPERAND (rbase2
, 0);
1583 if (rbase1
&& rbase2
1584 && (TREE_CODE (base1
) == MEM_REF
|| TREE_CODE (base1
) == TARGET_MEM_REF
)
1585 && (TREE_CODE (base2
) == MEM_REF
|| TREE_CODE (base2
) == TARGET_MEM_REF
)
1586 /* If the accesses are in the same restrict clique... */
1587 && MR_DEPENDENCE_CLIQUE (base1
) == MR_DEPENDENCE_CLIQUE (base2
)
1588 /* But based on different pointers they do not alias. */
1589 && MR_DEPENDENCE_BASE (base1
) != MR_DEPENDENCE_BASE (base2
))
1592 ind1_p
= (TREE_CODE (base1
) == MEM_REF
1593 || TREE_CODE (base1
) == TARGET_MEM_REF
);
1594 ind2_p
= (TREE_CODE (base2
) == MEM_REF
1595 || TREE_CODE (base2
) == TARGET_MEM_REF
);
1597 /* Canonicalize the pointer-vs-decl case. */
1598 if (ind1_p
&& var2_p
)
1600 std::swap (offset1
, offset2
);
1601 std::swap (max_size1
, max_size2
);
1602 std::swap (base1
, base2
);
1603 std::swap (ref1
, ref2
);
1610 /* First defer to TBAA if possible. */
1612 && flag_strict_aliasing
1613 && !alias_sets_conflict_p (ao_ref_alias_set (ref1
),
1614 ao_ref_alias_set (ref2
)))
1617 /* If the reference is based on a pointer that points to memory
1618 that may not be written to then the other reference cannot possibly
1620 if ((TREE_CODE (TREE_OPERAND (base2
, 0)) == SSA_NAME
1621 && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base2
, 0)))
1623 && TREE_CODE (TREE_OPERAND (base1
, 0)) == SSA_NAME
1624 && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base1
, 0))))
1627 /* Dispatch to the pointer-vs-decl or pointer-vs-pointer disambiguators. */
1628 if (var1_p
&& ind2_p
)
1629 return indirect_ref_may_alias_decl_p (ref2
->ref
, base2
,
1631 ao_ref_alias_set (ref2
),
1632 ao_ref_base_alias_set (ref2
),
1635 ao_ref_alias_set (ref1
),
1636 ao_ref_base_alias_set (ref1
),
1638 else if (ind1_p
&& ind2_p
)
1639 return indirect_refs_may_alias_p (ref1
->ref
, base1
,
1641 ao_ref_alias_set (ref1
),
1642 ao_ref_base_alias_set (ref1
),
1645 ao_ref_alias_set (ref2
),
1646 ao_ref_base_alias_set (ref2
),
1652 /* Return true, if the two memory references REF1 and REF2 may alias
1653 and update statistics. */
1656 refs_may_alias_p_1 (ao_ref
*ref1
, ao_ref
*ref2
, bool tbaa_p
)
1658 bool res
= refs_may_alias_p_2 (ref1
, ref2
, tbaa_p
);
1660 ++alias_stats
.refs_may_alias_p_may_alias
;
1662 ++alias_stats
.refs_may_alias_p_no_alias
;
1667 refs_may_alias_p (tree ref1
, ao_ref
*ref2
, bool tbaa_p
)
1670 ao_ref_init (&r1
, ref1
);
1671 return refs_may_alias_p_1 (&r1
, ref2
, tbaa_p
);
1675 refs_may_alias_p (tree ref1
, tree ref2
, bool tbaa_p
)
1678 ao_ref_init (&r1
, ref1
);
1679 ao_ref_init (&r2
, ref2
);
1680 return refs_may_alias_p_1 (&r1
, &r2
, tbaa_p
);
1683 /* Returns true if there is a anti-dependence for the STORE that
1684 executes after the LOAD. */
1687 refs_anti_dependent_p (tree load
, tree store
)
1690 ao_ref_init (&r1
, load
);
1691 ao_ref_init (&r2
, store
);
1692 return refs_may_alias_p_1 (&r1
, &r2
, false);
1695 /* Returns true if there is a output dependence for the stores
1696 STORE1 and STORE2. */
1699 refs_output_dependent_p (tree store1
, tree store2
)
1702 ao_ref_init (&r1
, store1
);
1703 ao_ref_init (&r2
, store2
);
1704 return refs_may_alias_p_1 (&r1
, &r2
, false);
1707 /* If the call CALL may use the memory reference REF return true,
1708 otherwise return false. */
1711 ref_maybe_used_by_call_p_1 (gcall
*call
, ao_ref
*ref
, bool tbaa_p
)
1715 int flags
= gimple_call_flags (call
);
1717 /* Const functions without a static chain do not implicitly use memory. */
1718 if (!gimple_call_chain (call
)
1719 && (flags
& (ECF_CONST
|ECF_NOVOPS
)))
1722 base
= ao_ref_base (ref
);
1726 /* A call that is not without side-effects might involve volatile
1727 accesses and thus conflicts with all other volatile accesses. */
1728 if (ref
->volatile_p
)
1731 /* If the reference is based on a decl that is not aliased the call
1732 cannot possibly use it. */
1734 && !may_be_aliased (base
)
1735 /* But local statics can be used through recursion. */
1736 && !is_global_var (base
))
1739 callee
= gimple_call_fndecl (call
);
1741 /* Handle those builtin functions explicitly that do not act as
1742 escape points. See tree-ssa-structalias.c:find_func_aliases
1743 for the list of builtins we might need to handle here. */
1744 if (callee
!= NULL_TREE
1745 && gimple_call_builtin_p (call
, BUILT_IN_NORMAL
))
1746 switch (DECL_FUNCTION_CODE (callee
))
1748 /* All the following functions read memory pointed to by
1749 their second argument. strcat/strncat additionally
1750 reads memory pointed to by the first argument. */
1751 case BUILT_IN_STRCAT
:
1752 case BUILT_IN_STRNCAT
:
1755 ao_ref_init_from_ptr_and_size (&dref
,
1756 gimple_call_arg (call
, 0),
1758 if (refs_may_alias_p_1 (&dref
, ref
, false))
1762 case BUILT_IN_STRCPY
:
1763 case BUILT_IN_STRNCPY
:
1764 case BUILT_IN_MEMCPY
:
1765 case BUILT_IN_MEMMOVE
:
1766 case BUILT_IN_MEMPCPY
:
1767 case BUILT_IN_STPCPY
:
1768 case BUILT_IN_STPNCPY
:
1769 case BUILT_IN_TM_MEMCPY
:
1770 case BUILT_IN_TM_MEMMOVE
:
1773 tree size
= NULL_TREE
;
1774 if (gimple_call_num_args (call
) == 3)
1775 size
= gimple_call_arg (call
, 2);
1776 ao_ref_init_from_ptr_and_size (&dref
,
1777 gimple_call_arg (call
, 1),
1779 return refs_may_alias_p_1 (&dref
, ref
, false);
1781 case BUILT_IN_STRCAT_CHK
:
1782 case BUILT_IN_STRNCAT_CHK
:
1785 ao_ref_init_from_ptr_and_size (&dref
,
1786 gimple_call_arg (call
, 0),
1788 if (refs_may_alias_p_1 (&dref
, ref
, false))
1792 case BUILT_IN_STRCPY_CHK
:
1793 case BUILT_IN_STRNCPY_CHK
:
1794 case BUILT_IN_MEMCPY_CHK
:
1795 case BUILT_IN_MEMMOVE_CHK
:
1796 case BUILT_IN_MEMPCPY_CHK
:
1797 case BUILT_IN_STPCPY_CHK
:
1798 case BUILT_IN_STPNCPY_CHK
:
1801 tree size
= NULL_TREE
;
1802 if (gimple_call_num_args (call
) == 4)
1803 size
= gimple_call_arg (call
, 2);
1804 ao_ref_init_from_ptr_and_size (&dref
,
1805 gimple_call_arg (call
, 1),
1807 return refs_may_alias_p_1 (&dref
, ref
, false);
1809 case BUILT_IN_BCOPY
:
1812 tree size
= gimple_call_arg (call
, 2);
1813 ao_ref_init_from_ptr_and_size (&dref
,
1814 gimple_call_arg (call
, 0),
1816 return refs_may_alias_p_1 (&dref
, ref
, false);
1819 /* The following functions read memory pointed to by their
1821 CASE_BUILT_IN_TM_LOAD (1):
1822 CASE_BUILT_IN_TM_LOAD (2):
1823 CASE_BUILT_IN_TM_LOAD (4):
1824 CASE_BUILT_IN_TM_LOAD (8):
1825 CASE_BUILT_IN_TM_LOAD (FLOAT
):
1826 CASE_BUILT_IN_TM_LOAD (DOUBLE
):
1827 CASE_BUILT_IN_TM_LOAD (LDOUBLE
):
1828 CASE_BUILT_IN_TM_LOAD (M64
):
1829 CASE_BUILT_IN_TM_LOAD (M128
):
1830 CASE_BUILT_IN_TM_LOAD (M256
):
1831 case BUILT_IN_TM_LOG
:
1832 case BUILT_IN_TM_LOG_1
:
1833 case BUILT_IN_TM_LOG_2
:
1834 case BUILT_IN_TM_LOG_4
:
1835 case BUILT_IN_TM_LOG_8
:
1836 case BUILT_IN_TM_LOG_FLOAT
:
1837 case BUILT_IN_TM_LOG_DOUBLE
:
1838 case BUILT_IN_TM_LOG_LDOUBLE
:
1839 case BUILT_IN_TM_LOG_M64
:
1840 case BUILT_IN_TM_LOG_M128
:
1841 case BUILT_IN_TM_LOG_M256
:
1842 return ptr_deref_may_alias_ref_p_1 (gimple_call_arg (call
, 0), ref
);
1844 /* These read memory pointed to by the first argument. */
1845 case BUILT_IN_STRDUP
:
1846 case BUILT_IN_STRNDUP
:
1847 case BUILT_IN_REALLOC
:
1850 tree size
= NULL_TREE
;
1851 if (gimple_call_num_args (call
) == 2)
1852 size
= gimple_call_arg (call
, 1);
1853 ao_ref_init_from_ptr_and_size (&dref
,
1854 gimple_call_arg (call
, 0),
1856 return refs_may_alias_p_1 (&dref
, ref
, false);
1858 /* These read memory pointed to by the first argument. */
1859 case BUILT_IN_INDEX
:
1860 case BUILT_IN_STRCHR
:
1861 case BUILT_IN_STRRCHR
:
1864 ao_ref_init_from_ptr_and_size (&dref
,
1865 gimple_call_arg (call
, 0),
1867 return refs_may_alias_p_1 (&dref
, ref
, false);
1869 /* These read memory pointed to by the first argument with size
1870 in the third argument. */
1871 case BUILT_IN_MEMCHR
:
1874 ao_ref_init_from_ptr_and_size (&dref
,
1875 gimple_call_arg (call
, 0),
1876 gimple_call_arg (call
, 2));
1877 return refs_may_alias_p_1 (&dref
, ref
, false);
1879 /* These read memory pointed to by the first and second arguments. */
1880 case BUILT_IN_STRSTR
:
1881 case BUILT_IN_STRPBRK
:
1884 ao_ref_init_from_ptr_and_size (&dref
,
1885 gimple_call_arg (call
, 0),
1887 if (refs_may_alias_p_1 (&dref
, ref
, false))
1889 ao_ref_init_from_ptr_and_size (&dref
,
1890 gimple_call_arg (call
, 1),
1892 return refs_may_alias_p_1 (&dref
, ref
, false);
1895 /* The following builtins do not read from memory. */
1897 case BUILT_IN_MALLOC
:
1898 case BUILT_IN_POSIX_MEMALIGN
:
1899 case BUILT_IN_ALIGNED_ALLOC
:
1900 case BUILT_IN_CALLOC
:
1901 CASE_BUILT_IN_ALLOCA
:
1902 case BUILT_IN_STACK_SAVE
:
1903 case BUILT_IN_STACK_RESTORE
:
1904 case BUILT_IN_MEMSET
:
1905 case BUILT_IN_TM_MEMSET
:
1906 case BUILT_IN_MEMSET_CHK
:
1907 case BUILT_IN_FREXP
:
1908 case BUILT_IN_FREXPF
:
1909 case BUILT_IN_FREXPL
:
1910 case BUILT_IN_GAMMA_R
:
1911 case BUILT_IN_GAMMAF_R
:
1912 case BUILT_IN_GAMMAL_R
:
1913 case BUILT_IN_LGAMMA_R
:
1914 case BUILT_IN_LGAMMAF_R
:
1915 case BUILT_IN_LGAMMAL_R
:
1917 case BUILT_IN_MODFF
:
1918 case BUILT_IN_MODFL
:
1919 case BUILT_IN_REMQUO
:
1920 case BUILT_IN_REMQUOF
:
1921 case BUILT_IN_REMQUOL
:
1922 case BUILT_IN_SINCOS
:
1923 case BUILT_IN_SINCOSF
:
1924 case BUILT_IN_SINCOSL
:
1925 case BUILT_IN_ASSUME_ALIGNED
:
1926 case BUILT_IN_VA_END
:
1928 /* __sync_* builtins and some OpenMP builtins act as threading
1930 #undef DEF_SYNC_BUILTIN
1931 #define DEF_SYNC_BUILTIN(ENUM, NAME, TYPE, ATTRS) case ENUM:
1932 #include "sync-builtins.def"
1933 #undef DEF_SYNC_BUILTIN
1934 case BUILT_IN_GOMP_ATOMIC_START
:
1935 case BUILT_IN_GOMP_ATOMIC_END
:
1936 case BUILT_IN_GOMP_BARRIER
:
1937 case BUILT_IN_GOMP_BARRIER_CANCEL
:
1938 case BUILT_IN_GOMP_TASKWAIT
:
1939 case BUILT_IN_GOMP_TASKGROUP_END
:
1940 case BUILT_IN_GOMP_CRITICAL_START
:
1941 case BUILT_IN_GOMP_CRITICAL_END
:
1942 case BUILT_IN_GOMP_CRITICAL_NAME_START
:
1943 case BUILT_IN_GOMP_CRITICAL_NAME_END
:
1944 case BUILT_IN_GOMP_LOOP_END
:
1945 case BUILT_IN_GOMP_LOOP_END_CANCEL
:
1946 case BUILT_IN_GOMP_ORDERED_START
:
1947 case BUILT_IN_GOMP_ORDERED_END
:
1948 case BUILT_IN_GOMP_SECTIONS_END
:
1949 case BUILT_IN_GOMP_SECTIONS_END_CANCEL
:
1950 case BUILT_IN_GOMP_SINGLE_COPY_START
:
1951 case BUILT_IN_GOMP_SINGLE_COPY_END
:
1955 /* Fallthru to general call handling. */;
1958 /* Check if base is a global static variable that is not read
1960 if (callee
!= NULL_TREE
&& VAR_P (base
) && TREE_STATIC (base
))
1962 struct cgraph_node
*node
= cgraph_node::get (callee
);
1965 /* FIXME: Callee can be an OMP builtin that does not have a call graph
1966 node yet. We should enforce that there are nodes for all decls in the
1967 IL and remove this check instead. */
1969 && (not_read
= ipa_reference_get_not_read_global (node
))
1970 && bitmap_bit_p (not_read
, ipa_reference_var_uid (base
)))
1974 /* Check if the base variable is call-used. */
1977 if (pt_solution_includes (gimple_call_use_set (call
), base
))
1980 else if ((TREE_CODE (base
) == MEM_REF
1981 || TREE_CODE (base
) == TARGET_MEM_REF
)
1982 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
)
1984 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (TREE_OPERAND (base
, 0));
1988 if (pt_solutions_intersect (gimple_call_use_set (call
), &pi
->pt
))
1994 /* Inspect call arguments for passed-by-value aliases. */
1996 for (i
= 0; i
< gimple_call_num_args (call
); ++i
)
1998 tree op
= gimple_call_arg (call
, i
);
1999 int flags
= gimple_call_arg_flags (call
, i
);
2001 if (flags
& EAF_UNUSED
)
2004 if (TREE_CODE (op
) == WITH_SIZE_EXPR
)
2005 op
= TREE_OPERAND (op
, 0);
2007 if (TREE_CODE (op
) != SSA_NAME
2008 && !is_gimple_min_invariant (op
))
2011 ao_ref_init (&r
, op
);
2012 if (refs_may_alias_p_1 (&r
, ref
, tbaa_p
))
2021 ref_maybe_used_by_call_p (gcall
*call
, ao_ref
*ref
, bool tbaa_p
)
2024 res
= ref_maybe_used_by_call_p_1 (call
, ref
, tbaa_p
);
2026 ++alias_stats
.ref_maybe_used_by_call_p_may_alias
;
2028 ++alias_stats
.ref_maybe_used_by_call_p_no_alias
;
2033 /* If the statement STMT may use the memory reference REF return
2034 true, otherwise return false. */
2037 ref_maybe_used_by_stmt_p (gimple
*stmt
, ao_ref
*ref
, bool tbaa_p
)
2039 if (is_gimple_assign (stmt
))
2043 /* All memory assign statements are single. */
2044 if (!gimple_assign_single_p (stmt
))
2047 rhs
= gimple_assign_rhs1 (stmt
);
2048 if (is_gimple_reg (rhs
)
2049 || is_gimple_min_invariant (rhs
)
2050 || gimple_assign_rhs_code (stmt
) == CONSTRUCTOR
)
2053 return refs_may_alias_p (rhs
, ref
, tbaa_p
);
2055 else if (is_gimple_call (stmt
))
2056 return ref_maybe_used_by_call_p (as_a
<gcall
*> (stmt
), ref
, tbaa_p
);
2057 else if (greturn
*return_stmt
= dyn_cast
<greturn
*> (stmt
))
2059 tree retval
= gimple_return_retval (return_stmt
);
2061 && TREE_CODE (retval
) != SSA_NAME
2062 && !is_gimple_min_invariant (retval
)
2063 && refs_may_alias_p (retval
, ref
, tbaa_p
))
2065 /* If ref escapes the function then the return acts as a use. */
2066 tree base
= ao_ref_base (ref
);
2069 else if (DECL_P (base
))
2070 return is_global_var (base
);
2071 else if (TREE_CODE (base
) == MEM_REF
2072 || TREE_CODE (base
) == TARGET_MEM_REF
)
2073 return ptr_deref_may_alias_global_p (TREE_OPERAND (base
, 0));
2081 ref_maybe_used_by_stmt_p (gimple
*stmt
, tree ref
, bool tbaa_p
)
2084 ao_ref_init (&r
, ref
);
2085 return ref_maybe_used_by_stmt_p (stmt
, &r
, tbaa_p
);
2088 /* If the call in statement CALL may clobber the memory reference REF
2089 return true, otherwise return false. */
2092 call_may_clobber_ref_p_1 (gcall
*call
, ao_ref
*ref
)
2097 /* If the call is pure or const it cannot clobber anything. */
2098 if (gimple_call_flags (call
)
2099 & (ECF_PURE
|ECF_CONST
|ECF_LOOPING_CONST_OR_PURE
|ECF_NOVOPS
))
2101 if (gimple_call_internal_p (call
))
2102 switch (gimple_call_internal_fn (call
))
2104 /* Treat these internal calls like ECF_PURE for aliasing,
2105 they don't write to any memory the program should care about.
2106 They have important other side-effects, and read memory,
2107 so can't be ECF_NOVOPS. */
2108 case IFN_UBSAN_NULL
:
2109 case IFN_UBSAN_BOUNDS
:
2110 case IFN_UBSAN_VPTR
:
2111 case IFN_UBSAN_OBJECT_SIZE
:
2113 case IFN_ASAN_CHECK
:
2119 base
= ao_ref_base (ref
);
2123 if (TREE_CODE (base
) == SSA_NAME
2124 || CONSTANT_CLASS_P (base
))
2127 /* A call that is not without side-effects might involve volatile
2128 accesses and thus conflicts with all other volatile accesses. */
2129 if (ref
->volatile_p
)
2132 /* If the reference is based on a decl that is not aliased the call
2133 cannot possibly clobber it. */
2135 && !may_be_aliased (base
)
2136 /* But local non-readonly statics can be modified through recursion
2137 or the call may implement a threading barrier which we must
2138 treat as may-def. */
2139 && (TREE_READONLY (base
)
2140 || !is_global_var (base
)))
2143 /* If the reference is based on a pointer that points to memory
2144 that may not be written to then the call cannot possibly clobber it. */
2145 if ((TREE_CODE (base
) == MEM_REF
2146 || TREE_CODE (base
) == TARGET_MEM_REF
)
2147 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
2148 && SSA_NAME_POINTS_TO_READONLY_MEMORY (TREE_OPERAND (base
, 0)))
2151 callee
= gimple_call_fndecl (call
);
2153 /* Handle those builtin functions explicitly that do not act as
2154 escape points. See tree-ssa-structalias.c:find_func_aliases
2155 for the list of builtins we might need to handle here. */
2156 if (callee
!= NULL_TREE
2157 && gimple_call_builtin_p (call
, BUILT_IN_NORMAL
))
2158 switch (DECL_FUNCTION_CODE (callee
))
2160 /* All the following functions clobber memory pointed to by
2161 their first argument. */
2162 case BUILT_IN_STRCPY
:
2163 case BUILT_IN_STRNCPY
:
2164 case BUILT_IN_MEMCPY
:
2165 case BUILT_IN_MEMMOVE
:
2166 case BUILT_IN_MEMPCPY
:
2167 case BUILT_IN_STPCPY
:
2168 case BUILT_IN_STPNCPY
:
2169 case BUILT_IN_STRCAT
:
2170 case BUILT_IN_STRNCAT
:
2171 case BUILT_IN_MEMSET
:
2172 case BUILT_IN_TM_MEMSET
:
2173 CASE_BUILT_IN_TM_STORE (1):
2174 CASE_BUILT_IN_TM_STORE (2):
2175 CASE_BUILT_IN_TM_STORE (4):
2176 CASE_BUILT_IN_TM_STORE (8):
2177 CASE_BUILT_IN_TM_STORE (FLOAT
):
2178 CASE_BUILT_IN_TM_STORE (DOUBLE
):
2179 CASE_BUILT_IN_TM_STORE (LDOUBLE
):
2180 CASE_BUILT_IN_TM_STORE (M64
):
2181 CASE_BUILT_IN_TM_STORE (M128
):
2182 CASE_BUILT_IN_TM_STORE (M256
):
2183 case BUILT_IN_TM_MEMCPY
:
2184 case BUILT_IN_TM_MEMMOVE
:
2187 tree size
= NULL_TREE
;
2188 /* Don't pass in size for strncat, as the maximum size
2189 is strlen (dest) + n + 1 instead of n, resp.
2190 n + 1 at dest + strlen (dest), but strlen (dest) isn't
2192 if (gimple_call_num_args (call
) == 3
2193 && DECL_FUNCTION_CODE (callee
) != BUILT_IN_STRNCAT
)
2194 size
= gimple_call_arg (call
, 2);
2195 ao_ref_init_from_ptr_and_size (&dref
,
2196 gimple_call_arg (call
, 0),
2198 return refs_may_alias_p_1 (&dref
, ref
, false);
2200 case BUILT_IN_STRCPY_CHK
:
2201 case BUILT_IN_STRNCPY_CHK
:
2202 case BUILT_IN_MEMCPY_CHK
:
2203 case BUILT_IN_MEMMOVE_CHK
:
2204 case BUILT_IN_MEMPCPY_CHK
:
2205 case BUILT_IN_STPCPY_CHK
:
2206 case BUILT_IN_STPNCPY_CHK
:
2207 case BUILT_IN_STRCAT_CHK
:
2208 case BUILT_IN_STRNCAT_CHK
:
2209 case BUILT_IN_MEMSET_CHK
:
2212 tree size
= NULL_TREE
;
2213 /* Don't pass in size for __strncat_chk, as the maximum size
2214 is strlen (dest) + n + 1 instead of n, resp.
2215 n + 1 at dest + strlen (dest), but strlen (dest) isn't
2217 if (gimple_call_num_args (call
) == 4
2218 && DECL_FUNCTION_CODE (callee
) != BUILT_IN_STRNCAT_CHK
)
2219 size
= gimple_call_arg (call
, 2);
2220 ao_ref_init_from_ptr_and_size (&dref
,
2221 gimple_call_arg (call
, 0),
2223 return refs_may_alias_p_1 (&dref
, ref
, false);
2225 case BUILT_IN_BCOPY
:
2228 tree size
= gimple_call_arg (call
, 2);
2229 ao_ref_init_from_ptr_and_size (&dref
,
2230 gimple_call_arg (call
, 1),
2232 return refs_may_alias_p_1 (&dref
, ref
, false);
2234 /* Allocating memory does not have any side-effects apart from
2235 being the definition point for the pointer. */
2236 case BUILT_IN_MALLOC
:
2237 case BUILT_IN_ALIGNED_ALLOC
:
2238 case BUILT_IN_CALLOC
:
2239 case BUILT_IN_STRDUP
:
2240 case BUILT_IN_STRNDUP
:
2241 /* Unix98 specifies that errno is set on allocation failure. */
2243 && targetm
.ref_may_alias_errno (ref
))
2246 case BUILT_IN_STACK_SAVE
:
2247 CASE_BUILT_IN_ALLOCA
:
2248 case BUILT_IN_ASSUME_ALIGNED
:
2250 /* But posix_memalign stores a pointer into the memory pointed to
2251 by its first argument. */
2252 case BUILT_IN_POSIX_MEMALIGN
:
2254 tree ptrptr
= gimple_call_arg (call
, 0);
2256 ao_ref_init_from_ptr_and_size (&dref
, ptrptr
,
2257 TYPE_SIZE_UNIT (ptr_type_node
));
2258 return (refs_may_alias_p_1 (&dref
, ref
, false)
2260 && targetm
.ref_may_alias_errno (ref
)));
2262 /* Freeing memory kills the pointed-to memory. More importantly
2263 the call has to serve as a barrier for moving loads and stores
2266 case BUILT_IN_VA_END
:
2268 tree ptr
= gimple_call_arg (call
, 0);
2269 return ptr_deref_may_alias_ref_p_1 (ptr
, ref
);
2271 /* Realloc serves both as allocation point and deallocation point. */
2272 case BUILT_IN_REALLOC
:
2274 tree ptr
= gimple_call_arg (call
, 0);
2275 /* Unix98 specifies that errno is set on allocation failure. */
2276 return ((flag_errno_math
2277 && targetm
.ref_may_alias_errno (ref
))
2278 || ptr_deref_may_alias_ref_p_1 (ptr
, ref
));
2280 case BUILT_IN_GAMMA_R
:
2281 case BUILT_IN_GAMMAF_R
:
2282 case BUILT_IN_GAMMAL_R
:
2283 case BUILT_IN_LGAMMA_R
:
2284 case BUILT_IN_LGAMMAF_R
:
2285 case BUILT_IN_LGAMMAL_R
:
2287 tree out
= gimple_call_arg (call
, 1);
2288 if (ptr_deref_may_alias_ref_p_1 (out
, ref
))
2290 if (flag_errno_math
)
2294 case BUILT_IN_FREXP
:
2295 case BUILT_IN_FREXPF
:
2296 case BUILT_IN_FREXPL
:
2298 case BUILT_IN_MODFF
:
2299 case BUILT_IN_MODFL
:
2301 tree out
= gimple_call_arg (call
, 1);
2302 return ptr_deref_may_alias_ref_p_1 (out
, ref
);
2304 case BUILT_IN_REMQUO
:
2305 case BUILT_IN_REMQUOF
:
2306 case BUILT_IN_REMQUOL
:
2308 tree out
= gimple_call_arg (call
, 2);
2309 if (ptr_deref_may_alias_ref_p_1 (out
, ref
))
2311 if (flag_errno_math
)
2315 case BUILT_IN_SINCOS
:
2316 case BUILT_IN_SINCOSF
:
2317 case BUILT_IN_SINCOSL
:
2319 tree sin
= gimple_call_arg (call
, 1);
2320 tree cos
= gimple_call_arg (call
, 2);
2321 return (ptr_deref_may_alias_ref_p_1 (sin
, ref
)
2322 || ptr_deref_may_alias_ref_p_1 (cos
, ref
));
2324 /* __sync_* builtins and some OpenMP builtins act as threading
2326 #undef DEF_SYNC_BUILTIN
2327 #define DEF_SYNC_BUILTIN(ENUM, NAME, TYPE, ATTRS) case ENUM:
2328 #include "sync-builtins.def"
2329 #undef DEF_SYNC_BUILTIN
2330 case BUILT_IN_GOMP_ATOMIC_START
:
2331 case BUILT_IN_GOMP_ATOMIC_END
:
2332 case BUILT_IN_GOMP_BARRIER
:
2333 case BUILT_IN_GOMP_BARRIER_CANCEL
:
2334 case BUILT_IN_GOMP_TASKWAIT
:
2335 case BUILT_IN_GOMP_TASKGROUP_END
:
2336 case BUILT_IN_GOMP_CRITICAL_START
:
2337 case BUILT_IN_GOMP_CRITICAL_END
:
2338 case BUILT_IN_GOMP_CRITICAL_NAME_START
:
2339 case BUILT_IN_GOMP_CRITICAL_NAME_END
:
2340 case BUILT_IN_GOMP_LOOP_END
:
2341 case BUILT_IN_GOMP_LOOP_END_CANCEL
:
2342 case BUILT_IN_GOMP_ORDERED_START
:
2343 case BUILT_IN_GOMP_ORDERED_END
:
2344 case BUILT_IN_GOMP_SECTIONS_END
:
2345 case BUILT_IN_GOMP_SECTIONS_END_CANCEL
:
2346 case BUILT_IN_GOMP_SINGLE_COPY_START
:
2347 case BUILT_IN_GOMP_SINGLE_COPY_END
:
2350 /* Fallthru to general call handling. */;
2353 /* Check if base is a global static variable that is not written
2355 if (callee
!= NULL_TREE
&& VAR_P (base
) && TREE_STATIC (base
))
2357 struct cgraph_node
*node
= cgraph_node::get (callee
);
2361 && (not_written
= ipa_reference_get_not_written_global (node
))
2362 && bitmap_bit_p (not_written
, ipa_reference_var_uid (base
)))
2366 /* Check if the base variable is call-clobbered. */
2368 return pt_solution_includes (gimple_call_clobber_set (call
), base
);
2369 else if ((TREE_CODE (base
) == MEM_REF
2370 || TREE_CODE (base
) == TARGET_MEM_REF
)
2371 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
)
2373 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (TREE_OPERAND (base
, 0));
2377 return pt_solutions_intersect (gimple_call_clobber_set (call
), &pi
->pt
);
2383 /* If the call in statement CALL may clobber the memory reference REF
2384 return true, otherwise return false. */
2387 call_may_clobber_ref_p (gcall
*call
, tree ref
)
2391 ao_ref_init (&r
, ref
);
2392 res
= call_may_clobber_ref_p_1 (call
, &r
);
2394 ++alias_stats
.call_may_clobber_ref_p_may_alias
;
2396 ++alias_stats
.call_may_clobber_ref_p_no_alias
;
2401 /* If the statement STMT may clobber the memory reference REF return true,
2402 otherwise return false. */
2405 stmt_may_clobber_ref_p_1 (gimple
*stmt
, ao_ref
*ref
, bool tbaa_p
)
2407 if (is_gimple_call (stmt
))
2409 tree lhs
= gimple_call_lhs (stmt
);
2411 && TREE_CODE (lhs
) != SSA_NAME
)
2414 ao_ref_init (&r
, lhs
);
2415 if (refs_may_alias_p_1 (ref
, &r
, tbaa_p
))
2419 return call_may_clobber_ref_p_1 (as_a
<gcall
*> (stmt
), ref
);
2421 else if (gimple_assign_single_p (stmt
))
2423 tree lhs
= gimple_assign_lhs (stmt
);
2424 if (TREE_CODE (lhs
) != SSA_NAME
)
2427 ao_ref_init (&r
, lhs
);
2428 return refs_may_alias_p_1 (ref
, &r
, tbaa_p
);
2431 else if (gimple_code (stmt
) == GIMPLE_ASM
)
2438 stmt_may_clobber_ref_p (gimple
*stmt
, tree ref
, bool tbaa_p
)
2441 ao_ref_init (&r
, ref
);
2442 return stmt_may_clobber_ref_p_1 (stmt
, &r
, tbaa_p
);
2445 /* Return true if store1 and store2 described by corresponding tuples
2446 <BASE, OFFSET, SIZE, MAX_SIZE> have the same size and store to the same
2450 same_addr_size_stores_p (tree base1
, poly_int64 offset1
, poly_int64 size1
,
2451 poly_int64 max_size1
,
2452 tree base2
, poly_int64 offset2
, poly_int64 size2
,
2453 poly_int64 max_size2
)
2455 /* Offsets need to be 0. */
2456 if (maybe_ne (offset1
, 0)
2457 || maybe_ne (offset2
, 0))
2460 bool base1_obj_p
= SSA_VAR_P (base1
);
2461 bool base2_obj_p
= SSA_VAR_P (base2
);
2463 /* We need one object. */
2464 if (base1_obj_p
== base2_obj_p
)
2466 tree obj
= base1_obj_p
? base1
: base2
;
2468 /* And we need one MEM_REF. */
2469 bool base1_memref_p
= TREE_CODE (base1
) == MEM_REF
;
2470 bool base2_memref_p
= TREE_CODE (base2
) == MEM_REF
;
2471 if (base1_memref_p
== base2_memref_p
)
2473 tree memref
= base1_memref_p
? base1
: base2
;
2475 /* Sizes need to be valid. */
2476 if (!known_size_p (max_size1
)
2477 || !known_size_p (max_size2
)
2478 || !known_size_p (size1
)
2479 || !known_size_p (size2
))
2482 /* Max_size needs to match size. */
2483 if (maybe_ne (max_size1
, size1
)
2484 || maybe_ne (max_size2
, size2
))
2487 /* Sizes need to match. */
2488 if (maybe_ne (size1
, size2
))
2492 /* Check that memref is a store to pointer with singleton points-to info. */
2493 if (!integer_zerop (TREE_OPERAND (memref
, 1)))
2495 tree ptr
= TREE_OPERAND (memref
, 0);
2496 if (TREE_CODE (ptr
) != SSA_NAME
)
2498 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (ptr
);
2499 unsigned int pt_uid
;
2501 || !pt_solution_singleton_or_null_p (&pi
->pt
, &pt_uid
))
2504 /* Be conservative with non-call exceptions when the address might
2506 if (cfun
->can_throw_non_call_exceptions
&& pi
->pt
.null
)
2509 /* Check that ptr points relative to obj. */
2510 unsigned int obj_uid
= DECL_PT_UID (obj
);
2511 if (obj_uid
!= pt_uid
)
2514 /* Check that the object size is the same as the store size. That ensures us
2515 that ptr points to the start of obj. */
2516 return (DECL_SIZE (obj
)
2517 && poly_int_tree_p (DECL_SIZE (obj
))
2518 && known_eq (wi::to_poly_offset (DECL_SIZE (obj
)), size1
));
2521 /* If STMT kills the memory reference REF return true, otherwise
2525 stmt_kills_ref_p (gimple
*stmt
, ao_ref
*ref
)
2527 if (!ao_ref_base (ref
))
2530 if (gimple_has_lhs (stmt
)
2531 && TREE_CODE (gimple_get_lhs (stmt
)) != SSA_NAME
2532 /* The assignment is not necessarily carried out if it can throw
2533 and we can catch it in the current function where we could inspect
2535 ??? We only need to care about the RHS throwing. For aggregate
2536 assignments or similar calls and non-call exceptions the LHS
2537 might throw as well. */
2538 && !stmt_can_throw_internal (cfun
, stmt
))
2540 tree lhs
= gimple_get_lhs (stmt
);
2541 /* If LHS is literally a base of the access we are done. */
2544 tree base
= ref
->ref
;
2545 tree innermost_dropped_array_ref
= NULL_TREE
;
2546 if (handled_component_p (base
))
2548 tree saved_lhs0
= NULL_TREE
;
2549 if (handled_component_p (lhs
))
2551 saved_lhs0
= TREE_OPERAND (lhs
, 0);
2552 TREE_OPERAND (lhs
, 0) = integer_zero_node
;
2556 /* Just compare the outermost handled component, if
2557 they are equal we have found a possible common
2559 tree saved_base0
= TREE_OPERAND (base
, 0);
2560 TREE_OPERAND (base
, 0) = integer_zero_node
;
2561 bool res
= operand_equal_p (lhs
, base
, 0);
2562 TREE_OPERAND (base
, 0) = saved_base0
;
2565 /* Remember if we drop an array-ref that we need to
2566 double-check not being at struct end. */
2567 if (TREE_CODE (base
) == ARRAY_REF
2568 || TREE_CODE (base
) == ARRAY_RANGE_REF
)
2569 innermost_dropped_array_ref
= base
;
2570 /* Otherwise drop handled components of the access. */
2573 while (handled_component_p (base
));
2575 TREE_OPERAND (lhs
, 0) = saved_lhs0
;
2577 /* Finally check if the lhs has the same address and size as the
2578 base candidate of the access. Watch out if we have dropped
2579 an array-ref that was at struct end, this means ref->ref may
2580 be outside of the TYPE_SIZE of its base. */
2581 if ((! innermost_dropped_array_ref
2582 || ! array_at_struct_end_p (innermost_dropped_array_ref
))
2584 || (((TYPE_SIZE (TREE_TYPE (lhs
))
2585 == TYPE_SIZE (TREE_TYPE (base
)))
2586 || (TYPE_SIZE (TREE_TYPE (lhs
))
2587 && TYPE_SIZE (TREE_TYPE (base
))
2588 && operand_equal_p (TYPE_SIZE (TREE_TYPE (lhs
)),
2589 TYPE_SIZE (TREE_TYPE (base
)),
2591 && operand_equal_p (lhs
, base
,
2593 | OEP_MATCH_SIDE_EFFECTS
))))
2597 /* Now look for non-literal equal bases with the restriction of
2598 handling constant offset and size. */
2599 /* For a must-alias check we need to be able to constrain
2600 the access properly. */
2601 if (!ref
->max_size_known_p ())
2603 poly_int64 size
, offset
, max_size
, ref_offset
= ref
->offset
;
2605 tree base
= get_ref_base_and_extent (lhs
, &offset
, &size
, &max_size
,
2607 /* We can get MEM[symbol: sZ, index: D.8862_1] here,
2608 so base == ref->base does not always hold. */
2609 if (base
!= ref
->base
)
2611 /* Try using points-to info. */
2612 if (same_addr_size_stores_p (base
, offset
, size
, max_size
, ref
->base
,
2613 ref
->offset
, ref
->size
, ref
->max_size
))
2616 /* If both base and ref->base are MEM_REFs, only compare the
2617 first operand, and if the second operand isn't equal constant,
2618 try to add the offsets into offset and ref_offset. */
2619 if (TREE_CODE (base
) == MEM_REF
&& TREE_CODE (ref
->base
) == MEM_REF
2620 && TREE_OPERAND (base
, 0) == TREE_OPERAND (ref
->base
, 0))
2622 if (!tree_int_cst_equal (TREE_OPERAND (base
, 1),
2623 TREE_OPERAND (ref
->base
, 1)))
2625 poly_offset_int off1
= mem_ref_offset (base
);
2626 off1
<<= LOG2_BITS_PER_UNIT
;
2628 poly_offset_int off2
= mem_ref_offset (ref
->base
);
2629 off2
<<= LOG2_BITS_PER_UNIT
;
2631 if (!off1
.to_shwi (&offset
) || !off2
.to_shwi (&ref_offset
))
2638 /* For a must-alias check we need to be able to constrain
2639 the access properly. */
2640 if (known_eq (size
, max_size
)
2641 && known_subrange_p (ref_offset
, ref
->max_size
, offset
, size
))
2645 if (is_gimple_call (stmt
))
2647 tree callee
= gimple_call_fndecl (stmt
);
2648 if (callee
!= NULL_TREE
2649 && gimple_call_builtin_p (stmt
, BUILT_IN_NORMAL
))
2650 switch (DECL_FUNCTION_CODE (callee
))
2654 tree ptr
= gimple_call_arg (stmt
, 0);
2655 tree base
= ao_ref_base (ref
);
2656 if (base
&& TREE_CODE (base
) == MEM_REF
2657 && TREE_OPERAND (base
, 0) == ptr
)
2662 case BUILT_IN_MEMCPY
:
2663 case BUILT_IN_MEMPCPY
:
2664 case BUILT_IN_MEMMOVE
:
2665 case BUILT_IN_MEMSET
:
2666 case BUILT_IN_MEMCPY_CHK
:
2667 case BUILT_IN_MEMPCPY_CHK
:
2668 case BUILT_IN_MEMMOVE_CHK
:
2669 case BUILT_IN_MEMSET_CHK
:
2670 case BUILT_IN_STRNCPY
:
2671 case BUILT_IN_STPNCPY
:
2673 /* For a must-alias check we need to be able to constrain
2674 the access properly. */
2675 if (!ref
->max_size_known_p ())
2677 tree dest
= gimple_call_arg (stmt
, 0);
2678 tree len
= gimple_call_arg (stmt
, 2);
2679 if (!poly_int_tree_p (len
))
2681 tree rbase
= ref
->base
;
2682 poly_offset_int roffset
= ref
->offset
;
2684 ao_ref_init_from_ptr_and_size (&dref
, dest
, len
);
2685 tree base
= ao_ref_base (&dref
);
2686 poly_offset_int offset
= dref
.offset
;
2687 if (!base
|| !known_size_p (dref
.size
))
2689 if (TREE_CODE (base
) == MEM_REF
)
2691 if (TREE_CODE (rbase
) != MEM_REF
)
2693 // Compare pointers.
2694 offset
+= mem_ref_offset (base
) << LOG2_BITS_PER_UNIT
;
2695 roffset
+= mem_ref_offset (rbase
) << LOG2_BITS_PER_UNIT
;
2696 base
= TREE_OPERAND (base
, 0);
2697 rbase
= TREE_OPERAND (rbase
, 0);
2700 && known_subrange_p (roffset
, ref
->max_size
, offset
,
2701 wi::to_poly_offset (len
)
2702 << LOG2_BITS_PER_UNIT
))
2707 case BUILT_IN_VA_END
:
2709 tree ptr
= gimple_call_arg (stmt
, 0);
2710 if (TREE_CODE (ptr
) == ADDR_EXPR
)
2712 tree base
= ao_ref_base (ref
);
2713 if (TREE_OPERAND (ptr
, 0) == base
)
2726 stmt_kills_ref_p (gimple
*stmt
, tree ref
)
2729 ao_ref_init (&r
, ref
);
2730 return stmt_kills_ref_p (stmt
, &r
);
2734 /* Walk the virtual use-def chain of VUSE until hitting the virtual operand
2735 TARGET or a statement clobbering the memory reference REF in which
2736 case false is returned. The walk starts with VUSE, one argument of PHI. */
2739 maybe_skip_until (gimple
*phi
, tree
&target
, basic_block target_bb
,
2740 ao_ref
*ref
, tree vuse
, unsigned int &limit
, bitmap
*visited
,
2741 bool abort_on_visited
,
2742 void *(*translate
)(ao_ref
*, tree
, void *, bool *),
2745 basic_block bb
= gimple_bb (phi
);
2748 *visited
= BITMAP_ALLOC (NULL
);
2750 bitmap_set_bit (*visited
, SSA_NAME_VERSION (PHI_RESULT (phi
)));
2752 /* Walk until we hit the target. */
2753 while (vuse
!= target
)
2755 gimple
*def_stmt
= SSA_NAME_DEF_STMT (vuse
);
2756 /* If we are searching for the target VUSE by walking up to
2757 TARGET_BB dominating the original PHI we are finished once
2758 we reach a default def or a definition in a block dominating
2759 that block. Update TARGET and return. */
2761 && (gimple_nop_p (def_stmt
)
2762 || dominated_by_p (CDI_DOMINATORS
,
2763 target_bb
, gimple_bb (def_stmt
))))
2769 /* Recurse for PHI nodes. */
2770 if (gimple_code (def_stmt
) == GIMPLE_PHI
)
2772 /* An already visited PHI node ends the walk successfully. */
2773 if (bitmap_bit_p (*visited
, SSA_NAME_VERSION (PHI_RESULT (def_stmt
))))
2774 return !abort_on_visited
;
2775 vuse
= get_continuation_for_phi (def_stmt
, ref
, limit
,
2776 visited
, abort_on_visited
,
2782 else if (gimple_nop_p (def_stmt
))
2786 /* A clobbering statement or the end of the IL ends it failing. */
2787 if ((int)limit
<= 0)
2790 if (stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
2792 bool disambiguate_only
= true;
2794 && (*translate
) (ref
, vuse
, data
, &disambiguate_only
) == NULL
)
2800 /* If we reach a new basic-block see if we already skipped it
2801 in a previous walk that ended successfully. */
2802 if (gimple_bb (def_stmt
) != bb
)
2804 if (!bitmap_set_bit (*visited
, SSA_NAME_VERSION (vuse
)))
2805 return !abort_on_visited
;
2806 bb
= gimple_bb (def_stmt
);
2808 vuse
= gimple_vuse (def_stmt
);
2814 /* Starting from a PHI node for the virtual operand of the memory reference
2815 REF find a continuation virtual operand that allows to continue walking
2816 statements dominating PHI skipping only statements that cannot possibly
2817 clobber REF. Decrements LIMIT for each alias disambiguation done
2818 and aborts the walk, returning NULL_TREE if it reaches zero.
2819 Returns NULL_TREE if no suitable virtual operand can be found. */
2822 get_continuation_for_phi (gimple
*phi
, ao_ref
*ref
,
2823 unsigned int &limit
, bitmap
*visited
,
2824 bool abort_on_visited
,
2825 void *(*translate
)(ao_ref
*, tree
, void *, bool *),
2828 unsigned nargs
= gimple_phi_num_args (phi
);
2830 /* Through a single-argument PHI we can simply look through. */
2832 return PHI_ARG_DEF (phi
, 0);
2834 /* For two or more arguments try to pairwise skip non-aliasing code
2835 until we hit the phi argument definition that dominates the other one. */
2836 basic_block phi_bb
= gimple_bb (phi
);
2840 /* Find a candidate for the virtual operand which definition
2841 dominates those of all others. */
2842 /* First look if any of the args themselves satisfy this. */
2843 for (i
= 0; i
< nargs
; ++i
)
2845 arg0
= PHI_ARG_DEF (phi
, i
);
2846 if (SSA_NAME_IS_DEFAULT_DEF (arg0
))
2848 basic_block def_bb
= gimple_bb (SSA_NAME_DEF_STMT (arg0
));
2849 if (def_bb
!= phi_bb
2850 && dominated_by_p (CDI_DOMINATORS
, phi_bb
, def_bb
))
2854 /* If not, look if we can reach such candidate by walking defs
2855 until we hit the immediate dominator. maybe_skip_until will
2857 basic_block dom
= get_immediate_dominator (CDI_DOMINATORS
, phi_bb
);
2859 /* Then check against the (to be) found candidate. */
2860 for (i
= 0; i
< nargs
; ++i
)
2862 arg1
= PHI_ARG_DEF (phi
, i
);
2865 else if (! maybe_skip_until (phi
, arg0
, dom
, ref
, arg1
, limit
, visited
,
2867 /* Do not translate when walking over
2871 gimple_bb (SSA_NAME_DEF_STMT (arg1
)),
2873 ? NULL
: translate
, data
))
2880 /* Based on the memory reference REF and its virtual use VUSE call
2881 WALKER for each virtual use that is equivalent to VUSE, including VUSE
2882 itself. That is, for each virtual use for which its defining statement
2883 does not clobber REF.
2885 WALKER is called with REF, the current virtual use and DATA. If
2886 WALKER returns non-NULL the walk stops and its result is returned.
2887 At the end of a non-successful walk NULL is returned.
2889 TRANSLATE if non-NULL is called with a pointer to REF, the virtual
2890 use which definition is a statement that may clobber REF and DATA.
2891 If TRANSLATE returns (void *)-1 the walk stops and NULL is returned.
2892 If TRANSLATE returns non-NULL the walk stops and its result is returned.
2893 If TRANSLATE returns NULL the walk continues and TRANSLATE is supposed
2894 to adjust REF and *DATA to make that valid.
2896 VALUEIZE if non-NULL is called with the next VUSE that is considered
2897 and return value is substituted for that. This can be used to
2898 implement optimistic value-numbering for example. Note that the
2899 VUSE argument is assumed to be valueized already.
2901 LIMIT specifies the number of alias queries we are allowed to do,
2902 the walk stops when it reaches zero and NULL is returned. LIMIT
2903 is decremented by the number of alias queries (plus adjustments
2904 done by the callbacks) upon return.
2906 TODO: Cache the vector of equivalent vuses per ref, vuse pair. */
2909 walk_non_aliased_vuses (ao_ref
*ref
, tree vuse
,
2910 void *(*walker
)(ao_ref
*, tree
, void *),
2911 void *(*translate
)(ao_ref
*, tree
, void *, bool *),
2912 tree (*valueize
)(tree
),
2913 unsigned &limit
, void *data
)
2915 bitmap visited
= NULL
;
2917 bool translated
= false;
2919 timevar_push (TV_ALIAS_STMT_WALK
);
2925 /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */
2926 res
= (*walker
) (ref
, vuse
, data
);
2928 if (res
== (void *)-1)
2933 /* Lookup succeeded. */
2934 else if (res
!= NULL
)
2939 vuse
= valueize (vuse
);
2946 def_stmt
= SSA_NAME_DEF_STMT (vuse
);
2947 if (gimple_nop_p (def_stmt
))
2949 else if (gimple_code (def_stmt
) == GIMPLE_PHI
)
2950 vuse
= get_continuation_for_phi (def_stmt
, ref
, limit
,
2951 &visited
, translated
, translate
, data
);
2954 if ((int)limit
<= 0)
2959 if (stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
2963 bool disambiguate_only
= false;
2964 res
= (*translate
) (ref
, vuse
, data
, &disambiguate_only
);
2965 /* Failed lookup and translation. */
2966 if (res
== (void *)-1)
2971 /* Lookup succeeded. */
2972 else if (res
!= NULL
)
2974 /* Translation succeeded, continue walking. */
2975 translated
= translated
|| !disambiguate_only
;
2977 vuse
= gimple_vuse (def_stmt
);
2983 BITMAP_FREE (visited
);
2985 timevar_pop (TV_ALIAS_STMT_WALK
);
2991 /* Based on the memory reference REF call WALKER for each vdef which
2992 defining statement may clobber REF, starting with VDEF. If REF
2993 is NULL_TREE, each defining statement is visited.
2995 WALKER is called with REF, the current vdef and DATA. If WALKER
2996 returns true the walk is stopped, otherwise it continues.
2998 If function entry is reached, FUNCTION_ENTRY_REACHED is set to true.
2999 The pointer may be NULL and then we do not track this information.
3001 At PHI nodes walk_aliased_vdefs forks into one walk for reach
3002 PHI argument (but only one walk continues on merge points), the
3003 return value is true if any of the walks was successful.
3005 The function returns the number of statements walked or -1 if
3006 LIMIT stmts were walked and the walk was aborted at this point.
3007 If LIMIT is zero the walk is not aborted. */
3010 walk_aliased_vdefs_1 (ao_ref
*ref
, tree vdef
,
3011 bool (*walker
)(ao_ref
*, tree
, void *), void *data
,
3012 bitmap
*visited
, unsigned int cnt
,
3013 bool *function_entry_reached
, unsigned limit
)
3017 gimple
*def_stmt
= SSA_NAME_DEF_STMT (vdef
);
3020 && !bitmap_set_bit (*visited
, SSA_NAME_VERSION (vdef
)))
3023 if (gimple_nop_p (def_stmt
))
3025 if (function_entry_reached
)
3026 *function_entry_reached
= true;
3029 else if (gimple_code (def_stmt
) == GIMPLE_PHI
)
3033 *visited
= BITMAP_ALLOC (NULL
);
3034 for (i
= 0; i
< gimple_phi_num_args (def_stmt
); ++i
)
3036 int res
= walk_aliased_vdefs_1 (ref
,
3037 gimple_phi_arg_def (def_stmt
, i
),
3038 walker
, data
, visited
, cnt
,
3039 function_entry_reached
, limit
);
3047 /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */
3052 || stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
3053 && (*walker
) (ref
, vdef
, data
))
3056 vdef
= gimple_vuse (def_stmt
);
3062 walk_aliased_vdefs (ao_ref
*ref
, tree vdef
,
3063 bool (*walker
)(ao_ref
*, tree
, void *), void *data
,
3065 bool *function_entry_reached
, unsigned int limit
)
3067 bitmap local_visited
= NULL
;
3070 timevar_push (TV_ALIAS_STMT_WALK
);
3072 if (function_entry_reached
)
3073 *function_entry_reached
= false;
3075 ret
= walk_aliased_vdefs_1 (ref
, vdef
, walker
, data
,
3076 visited
? visited
: &local_visited
, 0,
3077 function_entry_reached
, limit
);
3079 BITMAP_FREE (local_visited
);
3081 timevar_pop (TV_ALIAS_STMT_WALK
);