1 /* Alias analysis for trees.
2 Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011
3 Free Software Foundation, Inc.
4 Contributed by Diego Novillo <dnovillo@redhat.com>
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
24 #include "coretypes.h"
29 #include "basic-block.h"
32 #include "langhooks.h"
35 #include "tree-pretty-print.h"
36 #include "tree-dump.h"
38 #include "tree-flow.h"
39 #include "tree-inline.h"
40 #include "tree-pass.h"
46 #include "pointer-set.h"
47 #include "alloc-pool.h"
48 #include "tree-ssa-alias.h"
50 /* Broad overview of how alias analysis on gimple works:
52 Statements clobbering or using memory are linked through the
53 virtual operand factored use-def chain. The virtual operand
54 is unique per function, its symbol is accessible via gimple_vop (cfun).
55 Virtual operands are used for efficiently walking memory statements
56 in the gimple IL and are useful for things like value-numbering as
57 a generation count for memory references.
59 SSA_NAME pointers may have associated points-to information
60 accessible via the SSA_NAME_PTR_INFO macro. Flow-insensitive
61 points-to information is (re-)computed by the TODO_rebuild_alias
62 pass manager todo. Points-to information is also used for more
63 precise tracking of call-clobbered and call-used variables and
64 related disambiguations.
66 This file contains functions for disambiguating memory references,
67 the so called alias-oracle and tools for walking of the gimple IL.
69 The main alias-oracle entry-points are
71 bool stmt_may_clobber_ref_p (gimple, tree)
73 This function queries if a statement may invalidate (parts of)
74 the memory designated by the reference tree argument.
76 bool ref_maybe_used_by_stmt_p (gimple, tree)
78 This function queries if a statement may need (parts of) the
79 memory designated by the reference tree argument.
81 There are variants of these functions that only handle the call
82 part of a statement, call_may_clobber_ref_p and ref_maybe_used_by_call_p.
83 Note that these do not disambiguate against a possible call lhs.
85 bool refs_may_alias_p (tree, tree)
87 This function tries to disambiguate two reference trees.
89 bool ptr_deref_may_alias_global_p (tree)
91 This function queries if dereferencing a pointer variable may
94 More low-level disambiguators are available and documented in
95 this file. Low-level disambiguators dealing with points-to
96 information are in tree-ssa-structalias.c. */
99 /* Query statistics for the different low-level disambiguators.
100 A high-level query may trigger multiple of them. */
103 unsigned HOST_WIDE_INT refs_may_alias_p_may_alias
;
104 unsigned HOST_WIDE_INT refs_may_alias_p_no_alias
;
105 unsigned HOST_WIDE_INT ref_maybe_used_by_call_p_may_alias
;
106 unsigned HOST_WIDE_INT ref_maybe_used_by_call_p_no_alias
;
107 unsigned HOST_WIDE_INT call_may_clobber_ref_p_may_alias
;
108 unsigned HOST_WIDE_INT call_may_clobber_ref_p_no_alias
;
112 dump_alias_stats (FILE *s
)
114 fprintf (s
, "\nAlias oracle query stats:\n");
115 fprintf (s
, " refs_may_alias_p: "
116 HOST_WIDE_INT_PRINT_DEC
" disambiguations, "
117 HOST_WIDE_INT_PRINT_DEC
" queries\n",
118 alias_stats
.refs_may_alias_p_no_alias
,
119 alias_stats
.refs_may_alias_p_no_alias
120 + alias_stats
.refs_may_alias_p_may_alias
);
121 fprintf (s
, " ref_maybe_used_by_call_p: "
122 HOST_WIDE_INT_PRINT_DEC
" disambiguations, "
123 HOST_WIDE_INT_PRINT_DEC
" queries\n",
124 alias_stats
.ref_maybe_used_by_call_p_no_alias
,
125 alias_stats
.refs_may_alias_p_no_alias
126 + alias_stats
.ref_maybe_used_by_call_p_may_alias
);
127 fprintf (s
, " call_may_clobber_ref_p: "
128 HOST_WIDE_INT_PRINT_DEC
" disambiguations, "
129 HOST_WIDE_INT_PRINT_DEC
" queries\n",
130 alias_stats
.call_may_clobber_ref_p_no_alias
,
131 alias_stats
.call_may_clobber_ref_p_no_alias
132 + alias_stats
.call_may_clobber_ref_p_may_alias
);
136 /* Return true, if dereferencing PTR may alias with a global variable. */
139 ptr_deref_may_alias_global_p (tree ptr
)
141 struct ptr_info_def
*pi
;
143 /* If we end up with a pointer constant here that may point
145 if (TREE_CODE (ptr
) != SSA_NAME
)
148 pi
= SSA_NAME_PTR_INFO (ptr
);
150 /* If we do not have points-to information for this variable,
155 /* ??? This does not use TBAA to prune globals ptr may not access. */
156 return pt_solution_includes_global (&pi
->pt
);
159 /* Return true if dereferencing PTR may alias DECL.
160 The caller is responsible for applying TBAA to see if PTR
161 may access DECL at all. */
164 ptr_deref_may_alias_decl_p (tree ptr
, tree decl
)
166 struct ptr_info_def
*pi
;
168 /* Conversions are irrelevant for points-to information and
169 data-dependence analysis can feed us those. */
172 /* Anything we do not explicilty handle aliases. */
173 if ((TREE_CODE (ptr
) != SSA_NAME
174 && TREE_CODE (ptr
) != ADDR_EXPR
175 && TREE_CODE (ptr
) != POINTER_PLUS_EXPR
)
176 || !POINTER_TYPE_P (TREE_TYPE (ptr
))
177 || (TREE_CODE (decl
) != VAR_DECL
178 && TREE_CODE (decl
) != PARM_DECL
179 && TREE_CODE (decl
) != RESULT_DECL
))
182 /* Disregard pointer offsetting. */
183 if (TREE_CODE (ptr
) == POINTER_PLUS_EXPR
)
187 ptr
= TREE_OPERAND (ptr
, 0);
189 while (TREE_CODE (ptr
) == POINTER_PLUS_EXPR
);
190 return ptr_deref_may_alias_decl_p (ptr
, decl
);
193 /* ADDR_EXPR pointers either just offset another pointer or directly
194 specify the pointed-to set. */
195 if (TREE_CODE (ptr
) == ADDR_EXPR
)
197 tree base
= get_base_address (TREE_OPERAND (ptr
, 0));
199 && (TREE_CODE (base
) == MEM_REF
200 || TREE_CODE (base
) == TARGET_MEM_REF
))
201 ptr
= TREE_OPERAND (base
, 0);
206 && CONSTANT_CLASS_P (base
))
212 /* Non-aliased variables can not be pointed to. */
213 if (!may_be_aliased (decl
))
216 /* If we do not have useful points-to information for this pointer
217 we cannot disambiguate anything else. */
218 pi
= SSA_NAME_PTR_INFO (ptr
);
222 return pt_solution_includes (&pi
->pt
, decl
);
225 /* Return true if dereferenced PTR1 and PTR2 may alias.
226 The caller is responsible for applying TBAA to see if accesses
227 through PTR1 and PTR2 may conflict at all. */
230 ptr_derefs_may_alias_p (tree ptr1
, tree ptr2
)
232 struct ptr_info_def
*pi1
, *pi2
;
234 /* Conversions are irrelevant for points-to information and
235 data-dependence analysis can feed us those. */
239 /* Disregard pointer offsetting. */
240 if (TREE_CODE (ptr1
) == POINTER_PLUS_EXPR
)
244 ptr1
= TREE_OPERAND (ptr1
, 0);
246 while (TREE_CODE (ptr1
) == POINTER_PLUS_EXPR
);
247 return ptr_derefs_may_alias_p (ptr1
, ptr2
);
249 if (TREE_CODE (ptr2
) == POINTER_PLUS_EXPR
)
253 ptr2
= TREE_OPERAND (ptr2
, 0);
255 while (TREE_CODE (ptr2
) == POINTER_PLUS_EXPR
);
256 return ptr_derefs_may_alias_p (ptr1
, ptr2
);
259 /* ADDR_EXPR pointers either just offset another pointer or directly
260 specify the pointed-to set. */
261 if (TREE_CODE (ptr1
) == ADDR_EXPR
)
263 tree base
= get_base_address (TREE_OPERAND (ptr1
, 0));
265 && (TREE_CODE (base
) == MEM_REF
266 || TREE_CODE (base
) == TARGET_MEM_REF
))
267 return ptr_derefs_may_alias_p (TREE_OPERAND (base
, 0), ptr2
);
270 return ptr_deref_may_alias_decl_p (ptr2
, base
);
274 if (TREE_CODE (ptr2
) == ADDR_EXPR
)
276 tree base
= get_base_address (TREE_OPERAND (ptr2
, 0));
278 && (TREE_CODE (base
) == MEM_REF
279 || TREE_CODE (base
) == TARGET_MEM_REF
))
280 return ptr_derefs_may_alias_p (ptr1
, TREE_OPERAND (base
, 0));
283 return ptr_deref_may_alias_decl_p (ptr1
, base
);
288 /* From here we require SSA name pointers. Anything else aliases. */
289 if (TREE_CODE (ptr1
) != SSA_NAME
290 || TREE_CODE (ptr2
) != SSA_NAME
291 || !POINTER_TYPE_P (TREE_TYPE (ptr1
))
292 || !POINTER_TYPE_P (TREE_TYPE (ptr2
)))
295 /* We may end up with two empty points-to solutions for two same pointers.
296 In this case we still want to say both pointers alias, so shortcut
301 /* If we do not have useful points-to information for either pointer
302 we cannot disambiguate anything else. */
303 pi1
= SSA_NAME_PTR_INFO (ptr1
);
304 pi2
= SSA_NAME_PTR_INFO (ptr2
);
308 /* ??? This does not use TBAA to prune decls from the intersection
309 that not both pointers may access. */
310 return pt_solutions_intersect (&pi1
->pt
, &pi2
->pt
);
313 /* Return true if dereferencing PTR may alias *REF.
314 The caller is responsible for applying TBAA to see if PTR
315 may access *REF at all. */
318 ptr_deref_may_alias_ref_p_1 (tree ptr
, ao_ref
*ref
)
320 tree base
= ao_ref_base (ref
);
322 if (TREE_CODE (base
) == MEM_REF
323 || TREE_CODE (base
) == TARGET_MEM_REF
)
324 return ptr_derefs_may_alias_p (ptr
, TREE_OPERAND (base
, 0));
325 else if (DECL_P (base
))
326 return ptr_deref_may_alias_decl_p (ptr
, base
);
331 /* Return true whether REF may refer to global memory. */
334 ref_may_alias_global_p (tree ref
)
336 tree base
= get_base_address (ref
);
338 return is_global_var (base
);
339 else if (TREE_CODE (base
) == MEM_REF
340 || TREE_CODE (base
) == TARGET_MEM_REF
)
341 return ptr_deref_may_alias_global_p (TREE_OPERAND (base
, 0));
345 /* Return true whether STMT may clobber global memory. */
348 stmt_may_clobber_global_p (gimple stmt
)
352 if (!gimple_vdef (stmt
))
355 /* ??? We can ask the oracle whether an artificial pointer
356 dereference with a pointer with points-to information covering
357 all global memory (what about non-address taken memory?) maybe
358 clobbered by this call. As there is at the moment no convenient
359 way of doing that without generating garbage do some manual
361 ??? We could make a NULL ao_ref argument to the various
362 predicates special, meaning any global memory. */
364 switch (gimple_code (stmt
))
367 lhs
= gimple_assign_lhs (stmt
);
368 return (TREE_CODE (lhs
) != SSA_NAME
369 && ref_may_alias_global_p (lhs
));
378 /* Dump alias information on FILE. */
381 dump_alias_info (FILE *file
)
385 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
386 referenced_var_iterator rvi
;
389 fprintf (file
, "\n\nAlias information for %s\n\n", funcname
);
391 fprintf (file
, "Aliased symbols\n\n");
393 FOR_EACH_REFERENCED_VAR (cfun
, var
, rvi
)
395 if (may_be_aliased (var
))
396 dump_variable (file
, var
);
399 fprintf (file
, "\nCall clobber information\n");
401 fprintf (file
, "\nESCAPED");
402 dump_points_to_solution (file
, &cfun
->gimple_df
->escaped
);
404 fprintf (file
, "\n\nFlow-insensitive points-to information\n\n");
406 for (i
= 1; i
< num_ssa_names
; i
++)
408 tree ptr
= ssa_name (i
);
409 struct ptr_info_def
*pi
;
412 || SSA_NAME_IN_FREE_LIST (ptr
))
415 pi
= SSA_NAME_PTR_INFO (ptr
);
417 dump_points_to_info_for (file
, ptr
);
420 fprintf (file
, "\n");
424 /* Dump alias information on stderr. */
427 debug_alias_info (void)
429 dump_alias_info (stderr
);
433 /* Dump the points-to set *PT into FILE. */
436 dump_points_to_solution (FILE *file
, struct pt_solution
*pt
)
439 fprintf (file
, ", points-to anything");
442 fprintf (file
, ", points-to non-local");
445 fprintf (file
, ", points-to escaped");
448 fprintf (file
, ", points-to unit escaped");
451 fprintf (file
, ", points-to NULL");
455 fprintf (file
, ", points-to vars: ");
456 dump_decl_set (file
, pt
->vars
);
457 if (pt
->vars_contains_global
)
458 fprintf (file
, " (includes global vars)");
462 /* Dump points-to information for SSA_NAME PTR into FILE. */
465 dump_points_to_info_for (FILE *file
, tree ptr
)
467 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (ptr
);
469 print_generic_expr (file
, ptr
, dump_flags
);
472 dump_points_to_solution (file
, &pi
->pt
);
474 fprintf (file
, ", points-to anything");
476 fprintf (file
, "\n");
480 /* Dump points-to information for VAR into stderr. */
483 debug_points_to_info_for (tree var
)
485 dump_points_to_info_for (stderr
, var
);
489 /* Initializes the alias-oracle reference representation *R from REF. */
492 ao_ref_init (ao_ref
*r
, tree ref
)
499 r
->ref_alias_set
= -1;
500 r
->base_alias_set
= -1;
501 r
->volatile_p
= ref
? TREE_THIS_VOLATILE (ref
) : false;
504 /* Returns the base object of the memory reference *REF. */
507 ao_ref_base (ao_ref
*ref
)
511 ref
->base
= get_ref_base_and_extent (ref
->ref
, &ref
->offset
, &ref
->size
,
516 /* Returns the base object alias set of the memory reference *REF. */
518 static alias_set_type
519 ao_ref_base_alias_set (ao_ref
*ref
)
522 if (ref
->base_alias_set
!= -1)
523 return ref
->base_alias_set
;
527 while (handled_component_p (base_ref
))
528 base_ref
= TREE_OPERAND (base_ref
, 0);
529 ref
->base_alias_set
= get_alias_set (base_ref
);
530 return ref
->base_alias_set
;
533 /* Returns the reference alias set of the memory reference *REF. */
536 ao_ref_alias_set (ao_ref
*ref
)
538 if (ref
->ref_alias_set
!= -1)
539 return ref
->ref_alias_set
;
540 ref
->ref_alias_set
= get_alias_set (ref
->ref
);
541 return ref
->ref_alias_set
;
544 /* Init an alias-oracle reference representation from a gimple pointer
545 PTR and a gimple size SIZE in bytes. If SIZE is NULL_TREE the the
546 size is assumed to be unknown. The access is assumed to be only
547 to or after of the pointer target, not before it. */
550 ao_ref_init_from_ptr_and_size (ao_ref
*ref
, tree ptr
, tree size
)
552 HOST_WIDE_INT t1
, t2
;
553 ref
->ref
= NULL_TREE
;
554 if (TREE_CODE (ptr
) == ADDR_EXPR
)
555 ref
->base
= get_ref_base_and_extent (TREE_OPERAND (ptr
, 0),
556 &ref
->offset
, &t1
, &t2
);
559 ref
->base
= build2 (MEM_REF
, char_type_node
,
560 ptr
, null_pointer_node
);
564 && host_integerp (size
, 0)
565 && TREE_INT_CST_LOW (size
) * 8 / 8 == TREE_INT_CST_LOW (size
))
566 ref
->max_size
= ref
->size
= TREE_INT_CST_LOW (size
) * 8;
568 ref
->max_size
= ref
->size
= -1;
569 ref
->ref_alias_set
= 0;
570 ref
->base_alias_set
= 0;
571 ref
->volatile_p
= false;
574 /* Return 1 if TYPE1 and TYPE2 are to be considered equivalent for the
575 purpose of TBAA. Return 0 if they are distinct and -1 if we cannot
579 same_type_for_tbaa (tree type1
, tree type2
)
581 type1
= TYPE_MAIN_VARIANT (type1
);
582 type2
= TYPE_MAIN_VARIANT (type2
);
584 /* If we would have to do structural comparison bail out. */
585 if (TYPE_STRUCTURAL_EQUALITY_P (type1
)
586 || TYPE_STRUCTURAL_EQUALITY_P (type2
))
589 /* Compare the canonical types. */
590 if (TYPE_CANONICAL (type1
) == TYPE_CANONICAL (type2
))
593 /* ??? Array types are not properly unified in all cases as we have
594 spurious changes in the index types for example. Removing this
595 causes all sorts of problems with the Fortran frontend. */
596 if (TREE_CODE (type1
) == ARRAY_TYPE
597 && TREE_CODE (type2
) == ARRAY_TYPE
)
600 /* ??? In Ada, an lvalue of an unconstrained type can be used to access an
601 object of one of its constrained subtypes, e.g. when a function with an
602 unconstrained parameter passed by reference is called on an object and
603 inlined. But, even in the case of a fixed size, type and subtypes are
604 not equivalent enough as to share the same TYPE_CANONICAL, since this
605 would mean that conversions between them are useless, whereas they are
606 not (e.g. type and subtypes can have different modes). So, in the end,
607 they are only guaranteed to have the same alias set. */
608 if (get_alias_set (type1
) == get_alias_set (type2
))
611 /* The types are known to be not equal. */
615 /* Determine if the two component references REF1 and REF2 which are
616 based on access types TYPE1 and TYPE2 and of which at least one is based
617 on an indirect reference may alias. REF2 is the only one that can
618 be a decl in which case REF2_IS_DECL is true.
619 REF1_ALIAS_SET, BASE1_ALIAS_SET, REF2_ALIAS_SET and BASE2_ALIAS_SET
620 are the respective alias sets. */
623 aliasing_component_refs_p (tree ref1
,
624 alias_set_type ref1_alias_set
,
625 alias_set_type base1_alias_set
,
626 HOST_WIDE_INT offset1
, HOST_WIDE_INT max_size1
,
628 alias_set_type ref2_alias_set
,
629 alias_set_type base2_alias_set
,
630 HOST_WIDE_INT offset2
, HOST_WIDE_INT max_size2
,
633 /* If one reference is a component references through pointers try to find a
634 common base and apply offset based disambiguation. This handles
636 struct A { int i; int j; } *q;
637 struct B { struct A a; int k; } *p;
638 disambiguating q->i and p->a.j. */
644 /* Choose bases and base types to search for. */
646 while (handled_component_p (base1
))
647 base1
= TREE_OPERAND (base1
, 0);
648 type1
= TREE_TYPE (base1
);
650 while (handled_component_p (base2
))
651 base2
= TREE_OPERAND (base2
, 0);
652 type2
= TREE_TYPE (base2
);
654 /* Now search for the type1 in the access path of ref2. This
655 would be a common base for doing offset based disambiguation on. */
657 while (handled_component_p (*refp
)
658 && same_type_for_tbaa (TREE_TYPE (*refp
), type1
) == 0)
659 refp
= &TREE_OPERAND (*refp
, 0);
660 same_p
= same_type_for_tbaa (TREE_TYPE (*refp
), type1
);
661 /* If we couldn't compare types we have to bail out. */
664 else if (same_p
== 1)
666 HOST_WIDE_INT offadj
, sztmp
, msztmp
;
667 get_ref_base_and_extent (*refp
, &offadj
, &sztmp
, &msztmp
);
669 get_ref_base_and_extent (base1
, &offadj
, &sztmp
, &msztmp
);
671 return ranges_overlap_p (offset1
, max_size1
, offset2
, max_size2
);
673 /* If we didn't find a common base, try the other way around. */
675 while (handled_component_p (*refp
)
676 && same_type_for_tbaa (TREE_TYPE (*refp
), type2
) == 0)
677 refp
= &TREE_OPERAND (*refp
, 0);
678 same_p
= same_type_for_tbaa (TREE_TYPE (*refp
), type2
);
679 /* If we couldn't compare types we have to bail out. */
682 else if (same_p
== 1)
684 HOST_WIDE_INT offadj
, sztmp
, msztmp
;
685 get_ref_base_and_extent (*refp
, &offadj
, &sztmp
, &msztmp
);
687 get_ref_base_and_extent (base2
, &offadj
, &sztmp
, &msztmp
);
689 return ranges_overlap_p (offset1
, max_size1
, offset2
, max_size2
);
692 /* If we have two type access paths B1.path1 and B2.path2 they may
693 only alias if either B1 is in B2.path2 or B2 is in B1.path1.
694 But we can still have a path that goes B1.path1...B2.path2 with
695 a part that we do not see. So we can only disambiguate now
696 if there is no B2 in the tail of path1 and no B1 on the
698 if (base1_alias_set
== ref2_alias_set
699 || alias_set_subset_of (base1_alias_set
, ref2_alias_set
))
701 /* If this is ptr vs. decl then we know there is no ptr ... decl path. */
703 return (base2_alias_set
== ref1_alias_set
704 || alias_set_subset_of (base2_alias_set
, ref1_alias_set
));
708 /* Return true if two memory references based on the variables BASE1
709 and BASE2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and
710 [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. */
713 decl_refs_may_alias_p (tree base1
,
714 HOST_WIDE_INT offset1
, HOST_WIDE_INT max_size1
,
716 HOST_WIDE_INT offset2
, HOST_WIDE_INT max_size2
)
718 gcc_checking_assert (DECL_P (base1
) && DECL_P (base2
));
720 /* If both references are based on different variables, they cannot alias. */
724 /* If both references are based on the same variable, they cannot alias if
725 the accesses do not overlap. */
726 return ranges_overlap_p (offset1
, max_size1
, offset2
, max_size2
);
729 /* Return true if an indirect reference based on *PTR1 constrained
730 to [OFFSET1, OFFSET1 + MAX_SIZE1) may alias a variable based on BASE2
731 constrained to [OFFSET2, OFFSET2 + MAX_SIZE2). *PTR1 and BASE2 have
732 the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1
733 in which case they are computed on-demand. REF1 and REF2
734 if non-NULL are the complete memory reference trees. */
737 indirect_ref_may_alias_decl_p (tree ref1 ATTRIBUTE_UNUSED
, tree base1
,
738 HOST_WIDE_INT offset1
,
739 HOST_WIDE_INT max_size1 ATTRIBUTE_UNUSED
,
740 alias_set_type ref1_alias_set
,
741 alias_set_type base1_alias_set
,
742 tree ref2 ATTRIBUTE_UNUSED
, tree base2
,
743 HOST_WIDE_INT offset2
, HOST_WIDE_INT max_size2
,
744 alias_set_type ref2_alias_set
,
745 alias_set_type base2_alias_set
, bool tbaa_p
)
748 tree ptrtype1
, dbase2
;
749 HOST_WIDE_INT offset1p
= offset1
, offset2p
= offset2
;
750 HOST_WIDE_INT doffset1
, doffset2
;
753 gcc_checking_assert ((TREE_CODE (base1
) == MEM_REF
754 || TREE_CODE (base1
) == TARGET_MEM_REF
)
757 ptr1
= TREE_OPERAND (base1
, 0);
759 /* The offset embedded in MEM_REFs can be negative. Bias them
760 so that the resulting offset adjustment is positive. */
761 moff
= mem_ref_offset (base1
);
762 moff
= double_int_lshift (moff
,
764 ? 3 : exact_log2 (BITS_PER_UNIT
),
765 HOST_BITS_PER_DOUBLE_INT
, true);
766 if (double_int_negative_p (moff
))
767 offset2p
+= double_int_neg (moff
).low
;
769 offset1p
+= moff
.low
;
771 /* If only one reference is based on a variable, they cannot alias if
772 the pointer access is beyond the extent of the variable access.
773 (the pointer base cannot validly point to an offset less than zero
775 ??? IVOPTs creates bases that do not honor this restriction,
776 so do not apply this optimization for TARGET_MEM_REFs. */
777 if (TREE_CODE (base1
) != TARGET_MEM_REF
778 && !ranges_overlap_p (MAX (0, offset1p
), -1, offset2p
, max_size2
))
780 /* They also cannot alias if the pointer may not point to the decl. */
781 if (!ptr_deref_may_alias_decl_p (ptr1
, base2
))
784 /* Disambiguations that rely on strict aliasing rules follow. */
785 if (!flag_strict_aliasing
|| !tbaa_p
)
788 ptrtype1
= TREE_TYPE (TREE_OPERAND (base1
, 1));
790 /* If the alias set for a pointer access is zero all bets are off. */
791 if (base1_alias_set
== -1)
792 base1_alias_set
= get_deref_alias_set (ptrtype1
);
793 if (base1_alias_set
== 0)
795 if (base2_alias_set
== -1)
796 base2_alias_set
= get_alias_set (base2
);
798 /* When we are trying to disambiguate an access with a pointer dereference
799 as base versus one with a decl as base we can use both the size
800 of the decl and its dynamic type for extra disambiguation.
801 ??? We do not know anything about the dynamic type of the decl
802 other than that its alias-set contains base2_alias_set as a subset
803 which does not help us here. */
804 /* As we know nothing useful about the dynamic type of the decl just
805 use the usual conflict check rather than a subset test.
806 ??? We could introduce -fvery-strict-aliasing when the language
807 does not allow decls to have a dynamic type that differs from their
808 static type. Then we can check
809 !alias_set_subset_of (base1_alias_set, base2_alias_set) instead. */
810 if (base1_alias_set
!= base2_alias_set
811 && !alias_sets_conflict_p (base1_alias_set
, base2_alias_set
))
813 /* If the size of the access relevant for TBAA through the pointer
814 is bigger than the size of the decl we can't possibly access the
815 decl via that pointer. */
816 if (DECL_SIZE (base2
) && COMPLETE_TYPE_P (TREE_TYPE (ptrtype1
))
817 && TREE_CODE (DECL_SIZE (base2
)) == INTEGER_CST
818 && TREE_CODE (TYPE_SIZE (TREE_TYPE (ptrtype1
))) == INTEGER_CST
819 /* ??? This in turn may run afoul when a decl of type T which is
820 a member of union type U is accessed through a pointer to
821 type U and sizeof T is smaller than sizeof U. */
822 && TREE_CODE (TREE_TYPE (ptrtype1
)) != UNION_TYPE
823 && TREE_CODE (TREE_TYPE (ptrtype1
)) != QUAL_UNION_TYPE
824 && tree_int_cst_lt (DECL_SIZE (base2
), TYPE_SIZE (TREE_TYPE (ptrtype1
))))
830 /* If the decl is accessed via a MEM_REF, reconstruct the base
831 we can use for TBAA and an appropriately adjusted offset. */
833 while (handled_component_p (dbase2
))
834 dbase2
= TREE_OPERAND (dbase2
, 0);
837 if (TREE_CODE (dbase2
) == MEM_REF
838 || TREE_CODE (dbase2
) == TARGET_MEM_REF
)
840 double_int moff
= mem_ref_offset (dbase2
);
841 moff
= double_int_lshift (moff
,
843 ? 3 : exact_log2 (BITS_PER_UNIT
),
844 HOST_BITS_PER_DOUBLE_INT
, true);
845 if (double_int_negative_p (moff
))
846 doffset1
-= double_int_neg (moff
).low
;
848 doffset2
-= moff
.low
;
851 /* If either reference is view-converted, give up now. */
852 if (same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (ptrtype1
)) != 1
853 || same_type_for_tbaa (TREE_TYPE (dbase2
), TREE_TYPE (base2
)) != 1)
856 /* If both references are through the same type, they do not alias
857 if the accesses do not overlap. This does extra disambiguation
858 for mixed/pointer accesses but requires strict aliasing.
859 For MEM_REFs we require that the component-ref offset we computed
860 is relative to the start of the type which we ensure by
861 comparing rvalue and access type and disregarding the constant
863 if ((TREE_CODE (base1
) != TARGET_MEM_REF
864 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
865 && same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (dbase2
)) == 1)
866 return ranges_overlap_p (doffset1
, max_size1
, doffset2
, max_size2
);
868 /* Do access-path based disambiguation. */
870 && (handled_component_p (ref1
) || handled_component_p (ref2
)))
871 return aliasing_component_refs_p (ref1
,
872 ref1_alias_set
, base1_alias_set
,
875 ref2_alias_set
, base2_alias_set
,
876 offset2
, max_size2
, true);
881 /* Return true if two indirect references based on *PTR1
882 and *PTR2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and
883 [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. *PTR1 and *PTR2 have
884 the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1
885 in which case they are computed on-demand. REF1 and REF2
886 if non-NULL are the complete memory reference trees. */
889 indirect_refs_may_alias_p (tree ref1 ATTRIBUTE_UNUSED
, tree base1
,
890 HOST_WIDE_INT offset1
, HOST_WIDE_INT max_size1
,
891 alias_set_type ref1_alias_set
,
892 alias_set_type base1_alias_set
,
893 tree ref2 ATTRIBUTE_UNUSED
, tree base2
,
894 HOST_WIDE_INT offset2
, HOST_WIDE_INT max_size2
,
895 alias_set_type ref2_alias_set
,
896 alias_set_type base2_alias_set
, bool tbaa_p
)
900 tree ptrtype1
, ptrtype2
;
902 gcc_checking_assert ((TREE_CODE (base1
) == MEM_REF
903 || TREE_CODE (base1
) == TARGET_MEM_REF
)
904 && (TREE_CODE (base2
) == MEM_REF
905 || TREE_CODE (base2
) == TARGET_MEM_REF
));
907 ptr1
= TREE_OPERAND (base1
, 0);
908 ptr2
= TREE_OPERAND (base2
, 0);
910 /* If both bases are based on pointers they cannot alias if they may not
911 point to the same memory object or if they point to the same object
912 and the accesses do not overlap. */
913 if ((!cfun
|| gimple_in_ssa_p (cfun
))
914 && operand_equal_p (ptr1
, ptr2
, 0)
915 && (((TREE_CODE (base1
) != TARGET_MEM_REF
916 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
917 && (TREE_CODE (base2
) != TARGET_MEM_REF
918 || (!TMR_INDEX (base2
) && !TMR_INDEX2 (base2
))))
919 || (TREE_CODE (base1
) == TARGET_MEM_REF
920 && TREE_CODE (base2
) == TARGET_MEM_REF
921 && (TMR_STEP (base1
) == TMR_STEP (base2
)
922 || (TMR_STEP (base1
) && TMR_STEP (base2
)
923 && operand_equal_p (TMR_STEP (base1
),
924 TMR_STEP (base2
), 0)))
925 && (TMR_INDEX (base1
) == TMR_INDEX (base2
)
926 || (TMR_INDEX (base1
) && TMR_INDEX (base2
)
927 && operand_equal_p (TMR_INDEX (base1
),
928 TMR_INDEX (base2
), 0)))
929 && (TMR_INDEX2 (base1
) == TMR_INDEX2 (base2
)
930 || (TMR_INDEX2 (base1
) && TMR_INDEX2 (base2
)
931 && operand_equal_p (TMR_INDEX2 (base1
),
932 TMR_INDEX2 (base2
), 0))))))
935 /* The offset embedded in MEM_REFs can be negative. Bias them
936 so that the resulting offset adjustment is positive. */
937 moff
= mem_ref_offset (base1
);
938 moff
= double_int_lshift (moff
,
940 ? 3 : exact_log2 (BITS_PER_UNIT
),
941 HOST_BITS_PER_DOUBLE_INT
, true);
942 if (double_int_negative_p (moff
))
943 offset2
+= double_int_neg (moff
).low
;
946 moff
= mem_ref_offset (base2
);
947 moff
= double_int_lshift (moff
,
949 ? 3 : exact_log2 (BITS_PER_UNIT
),
950 HOST_BITS_PER_DOUBLE_INT
, true);
951 if (double_int_negative_p (moff
))
952 offset1
+= double_int_neg (moff
).low
;
955 return ranges_overlap_p (offset1
, max_size1
, offset2
, max_size2
);
957 if (!ptr_derefs_may_alias_p (ptr1
, ptr2
))
960 /* Disambiguations that rely on strict aliasing rules follow. */
961 if (!flag_strict_aliasing
|| !tbaa_p
)
964 ptrtype1
= TREE_TYPE (TREE_OPERAND (base1
, 1));
965 ptrtype2
= TREE_TYPE (TREE_OPERAND (base2
, 1));
967 /* If the alias set for a pointer access is zero all bets are off. */
968 if (base1_alias_set
== -1)
969 base1_alias_set
= get_deref_alias_set (ptrtype1
);
970 if (base1_alias_set
== 0)
972 if (base2_alias_set
== -1)
973 base2_alias_set
= get_deref_alias_set (ptrtype2
);
974 if (base2_alias_set
== 0)
977 /* If both references are through the same type, they do not alias
978 if the accesses do not overlap. This does extra disambiguation
979 for mixed/pointer accesses but requires strict aliasing. */
980 if ((TREE_CODE (base1
) != TARGET_MEM_REF
981 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
982 && (TREE_CODE (base2
) != TARGET_MEM_REF
983 || (!TMR_INDEX (base2
) && !TMR_INDEX2 (base2
)))
984 && same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (ptrtype1
)) == 1
985 && same_type_for_tbaa (TREE_TYPE (base2
), TREE_TYPE (ptrtype2
)) == 1
986 && same_type_for_tbaa (TREE_TYPE (ptrtype1
),
987 TREE_TYPE (ptrtype2
)) == 1)
988 return ranges_overlap_p (offset1
, max_size1
, offset2
, max_size2
);
990 /* Do type-based disambiguation. */
991 if (base1_alias_set
!= base2_alias_set
992 && !alias_sets_conflict_p (base1_alias_set
, base2_alias_set
))
995 /* Do access-path based disambiguation. */
997 && (handled_component_p (ref1
) || handled_component_p (ref2
))
998 && same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (ptrtype1
)) == 1
999 && same_type_for_tbaa (TREE_TYPE (base2
), TREE_TYPE (ptrtype2
)) == 1)
1000 return aliasing_component_refs_p (ref1
,
1001 ref1_alias_set
, base1_alias_set
,
1004 ref2_alias_set
, base2_alias_set
,
1005 offset2
, max_size2
, false);
1010 /* Return true, if the two memory references REF1 and REF2 may alias. */
1013 refs_may_alias_p_1 (ao_ref
*ref1
, ao_ref
*ref2
, bool tbaa_p
)
1016 HOST_WIDE_INT offset1
= 0, offset2
= 0;
1017 HOST_WIDE_INT max_size1
= -1, max_size2
= -1;
1018 bool var1_p
, var2_p
, ind1_p
, ind2_p
;
1020 gcc_checking_assert ((!ref1
->ref
1021 || TREE_CODE (ref1
->ref
) == SSA_NAME
1022 || DECL_P (ref1
->ref
)
1023 || TREE_CODE (ref1
->ref
) == STRING_CST
1024 || handled_component_p (ref1
->ref
)
1025 || TREE_CODE (ref1
->ref
) == MEM_REF
1026 || TREE_CODE (ref1
->ref
) == TARGET_MEM_REF
)
1028 || TREE_CODE (ref2
->ref
) == SSA_NAME
1029 || DECL_P (ref2
->ref
)
1030 || TREE_CODE (ref2
->ref
) == STRING_CST
1031 || handled_component_p (ref2
->ref
)
1032 || TREE_CODE (ref2
->ref
) == MEM_REF
1033 || TREE_CODE (ref2
->ref
) == TARGET_MEM_REF
));
1035 /* Decompose the references into their base objects and the access. */
1036 base1
= ao_ref_base (ref1
);
1037 offset1
= ref1
->offset
;
1038 max_size1
= ref1
->max_size
;
1039 base2
= ao_ref_base (ref2
);
1040 offset2
= ref2
->offset
;
1041 max_size2
= ref2
->max_size
;
1043 /* We can end up with registers or constants as bases for example from
1044 *D.1663_44 = VIEW_CONVERT_EXPR<struct DB_LSN>(__tmp$B0F64_59);
1045 which is seen as a struct copy. */
1046 if (TREE_CODE (base1
) == SSA_NAME
1047 || TREE_CODE (base1
) == CONST_DECL
1048 || TREE_CODE (base1
) == CONSTRUCTOR
1049 || TREE_CODE (base1
) == ADDR_EXPR
1050 || CONSTANT_CLASS_P (base1
)
1051 || TREE_CODE (base2
) == SSA_NAME
1052 || TREE_CODE (base2
) == CONST_DECL
1053 || TREE_CODE (base2
) == CONSTRUCTOR
1054 || TREE_CODE (base2
) == ADDR_EXPR
1055 || CONSTANT_CLASS_P (base2
))
1058 /* We can end up referring to code via function and label decls.
1059 As we likely do not properly track code aliases conservatively
1061 if (TREE_CODE (base1
) == FUNCTION_DECL
1062 || TREE_CODE (base1
) == LABEL_DECL
1063 || TREE_CODE (base2
) == FUNCTION_DECL
1064 || TREE_CODE (base2
) == LABEL_DECL
)
1067 /* Two volatile accesses always conflict. */
1068 if (ref1
->volatile_p
1069 && ref2
->volatile_p
)
1072 /* Defer to simple offset based disambiguation if we have
1073 references based on two decls. Do this before defering to
1074 TBAA to handle must-alias cases in conformance with the
1075 GCC extension of allowing type-punning through unions. */
1076 var1_p
= DECL_P (base1
);
1077 var2_p
= DECL_P (base2
);
1078 if (var1_p
&& var2_p
)
1079 return decl_refs_may_alias_p (base1
, offset1
, max_size1
,
1080 base2
, offset2
, max_size2
);
1082 ind1_p
= (TREE_CODE (base1
) == MEM_REF
1083 || TREE_CODE (base1
) == TARGET_MEM_REF
);
1084 ind2_p
= (TREE_CODE (base2
) == MEM_REF
1085 || TREE_CODE (base2
) == TARGET_MEM_REF
);
1087 /* Canonicalize the pointer-vs-decl case. */
1088 if (ind1_p
&& var2_p
)
1093 tmp1
= offset1
; offset1
= offset2
; offset2
= tmp1
;
1094 tmp1
= max_size1
; max_size1
= max_size2
; max_size2
= tmp1
;
1095 tmp2
= base1
; base1
= base2
; base2
= tmp2
;
1096 tmp3
= ref1
; ref1
= ref2
; ref2
= tmp3
;
1103 /* First defer to TBAA if possible. */
1105 && flag_strict_aliasing
1106 && !alias_sets_conflict_p (ao_ref_alias_set (ref1
),
1107 ao_ref_alias_set (ref2
)))
1110 /* Dispatch to the pointer-vs-decl or pointer-vs-pointer disambiguators. */
1111 if (var1_p
&& ind2_p
)
1112 return indirect_ref_may_alias_decl_p (ref2
->ref
, base2
,
1114 ao_ref_alias_set (ref2
), -1,
1117 ao_ref_alias_set (ref1
),
1118 ao_ref_base_alias_set (ref1
),
1120 else if (ind1_p
&& ind2_p
)
1121 return indirect_refs_may_alias_p (ref1
->ref
, base1
,
1123 ao_ref_alias_set (ref1
), -1,
1126 ao_ref_alias_set (ref2
), -1,
1129 /* We really do not want to end up here, but returning true is safe. */
1130 #ifdef ENABLE_CHECKING
1138 refs_may_alias_p (tree ref1
, tree ref2
)
1142 ao_ref_init (&r1
, ref1
);
1143 ao_ref_init (&r2
, ref2
);
1144 res
= refs_may_alias_p_1 (&r1
, &r2
, true);
1146 ++alias_stats
.refs_may_alias_p_may_alias
;
1148 ++alias_stats
.refs_may_alias_p_no_alias
;
1152 /* Returns true if there is a anti-dependence for the STORE that
1153 executes after the LOAD. */
1156 refs_anti_dependent_p (tree load
, tree store
)
1159 ao_ref_init (&r1
, load
);
1160 ao_ref_init (&r2
, store
);
1161 return refs_may_alias_p_1 (&r1
, &r2
, false);
1164 /* Returns true if there is a output dependence for the stores
1165 STORE1 and STORE2. */
1168 refs_output_dependent_p (tree store1
, tree store2
)
1171 ao_ref_init (&r1
, store1
);
1172 ao_ref_init (&r2
, store2
);
1173 return refs_may_alias_p_1 (&r1
, &r2
, false);
1176 /* If the call CALL may use the memory reference REF return true,
1177 otherwise return false. */
1180 ref_maybe_used_by_call_p_1 (gimple call
, ao_ref
*ref
)
1184 int flags
= gimple_call_flags (call
);
1186 /* Const functions without a static chain do not implicitly use memory. */
1187 if (!gimple_call_chain (call
)
1188 && (flags
& (ECF_CONST
|ECF_NOVOPS
)))
1191 base
= ao_ref_base (ref
);
1195 /* A call that is not without side-effects might involve volatile
1196 accesses and thus conflicts with all other volatile accesses. */
1197 if (ref
->volatile_p
)
1200 /* If the reference is based on a decl that is not aliased the call
1201 cannot possibly use it. */
1203 && !may_be_aliased (base
)
1204 /* But local statics can be used through recursion. */
1205 && !is_global_var (base
))
1208 callee
= gimple_call_fndecl (call
);
1210 /* Handle those builtin functions explicitly that do not act as
1211 escape points. See tree-ssa-structalias.c:find_func_aliases
1212 for the list of builtins we might need to handle here. */
1213 if (callee
!= NULL_TREE
1214 && DECL_BUILT_IN_CLASS (callee
) == BUILT_IN_NORMAL
)
1215 switch (DECL_FUNCTION_CODE (callee
))
1217 /* All the following functions read memory pointed to by
1218 their second argument. strcat/strncat additionally
1219 reads memory pointed to by the first argument. */
1220 case BUILT_IN_STRCAT
:
1221 case BUILT_IN_STRNCAT
:
1224 ao_ref_init_from_ptr_and_size (&dref
,
1225 gimple_call_arg (call
, 0),
1227 if (refs_may_alias_p_1 (&dref
, ref
, false))
1231 case BUILT_IN_STRCPY
:
1232 case BUILT_IN_STRNCPY
:
1233 case BUILT_IN_MEMCPY
:
1234 case BUILT_IN_MEMMOVE
:
1235 case BUILT_IN_MEMPCPY
:
1236 case BUILT_IN_STPCPY
:
1237 case BUILT_IN_STPNCPY
:
1238 case BUILT_IN_TM_MEMCPY
:
1239 case BUILT_IN_TM_MEMMOVE
:
1242 tree size
= NULL_TREE
;
1243 if (gimple_call_num_args (call
) == 3)
1244 size
= gimple_call_arg (call
, 2);
1245 ao_ref_init_from_ptr_and_size (&dref
,
1246 gimple_call_arg (call
, 1),
1248 return refs_may_alias_p_1 (&dref
, ref
, false);
1250 case BUILT_IN_STRCAT_CHK
:
1251 case BUILT_IN_STRNCAT_CHK
:
1254 ao_ref_init_from_ptr_and_size (&dref
,
1255 gimple_call_arg (call
, 0),
1257 if (refs_may_alias_p_1 (&dref
, ref
, false))
1261 case BUILT_IN_STRCPY_CHK
:
1262 case BUILT_IN_STRNCPY_CHK
:
1263 case BUILT_IN_MEMCPY_CHK
:
1264 case BUILT_IN_MEMMOVE_CHK
:
1265 case BUILT_IN_MEMPCPY_CHK
:
1266 case BUILT_IN_STPCPY_CHK
:
1267 case BUILT_IN_STPNCPY_CHK
:
1270 tree size
= NULL_TREE
;
1271 if (gimple_call_num_args (call
) == 4)
1272 size
= gimple_call_arg (call
, 2);
1273 ao_ref_init_from_ptr_and_size (&dref
,
1274 gimple_call_arg (call
, 1),
1276 return refs_may_alias_p_1 (&dref
, ref
, false);
1278 case BUILT_IN_BCOPY
:
1281 tree size
= gimple_call_arg (call
, 2);
1282 ao_ref_init_from_ptr_and_size (&dref
,
1283 gimple_call_arg (call
, 0),
1285 return refs_may_alias_p_1 (&dref
, ref
, false);
1288 /* The following functions read memory pointed to by their
1290 CASE_BUILT_IN_TM_LOAD (1):
1291 CASE_BUILT_IN_TM_LOAD (2):
1292 CASE_BUILT_IN_TM_LOAD (4):
1293 CASE_BUILT_IN_TM_LOAD (8):
1294 CASE_BUILT_IN_TM_LOAD (FLOAT
):
1295 CASE_BUILT_IN_TM_LOAD (DOUBLE
):
1296 CASE_BUILT_IN_TM_LOAD (LDOUBLE
):
1297 CASE_BUILT_IN_TM_LOAD (M64
):
1298 CASE_BUILT_IN_TM_LOAD (M128
):
1299 CASE_BUILT_IN_TM_LOAD (M256
):
1300 case BUILT_IN_TM_LOG
:
1301 case BUILT_IN_TM_LOG_1
:
1302 case BUILT_IN_TM_LOG_2
:
1303 case BUILT_IN_TM_LOG_4
:
1304 case BUILT_IN_TM_LOG_8
:
1305 case BUILT_IN_TM_LOG_FLOAT
:
1306 case BUILT_IN_TM_LOG_DOUBLE
:
1307 case BUILT_IN_TM_LOG_LDOUBLE
:
1308 case BUILT_IN_TM_LOG_M64
:
1309 case BUILT_IN_TM_LOG_M128
:
1310 case BUILT_IN_TM_LOG_M256
:
1311 return ptr_deref_may_alias_ref_p_1 (gimple_call_arg (call
, 0), ref
);
1313 /* These read memory pointed to by the first argument. */
1314 case BUILT_IN_STRDUP
:
1315 case BUILT_IN_STRNDUP
:
1318 tree size
= NULL_TREE
;
1319 if (gimple_call_num_args (call
) == 2)
1320 size
= gimple_call_arg (call
, 1);
1321 ao_ref_init_from_ptr_and_size (&dref
,
1322 gimple_call_arg (call
, 0),
1324 return refs_may_alias_p_1 (&dref
, ref
, false);
1326 /* The following builtins do not read from memory. */
1328 case BUILT_IN_MALLOC
:
1329 case BUILT_IN_CALLOC
:
1330 case BUILT_IN_ALLOCA
:
1331 case BUILT_IN_ALLOCA_WITH_ALIGN
:
1332 case BUILT_IN_STACK_SAVE
:
1333 case BUILT_IN_STACK_RESTORE
:
1334 case BUILT_IN_MEMSET
:
1335 case BUILT_IN_TM_MEMSET
:
1336 case BUILT_IN_MEMSET_CHK
:
1337 case BUILT_IN_FREXP
:
1338 case BUILT_IN_FREXPF
:
1339 case BUILT_IN_FREXPL
:
1340 case BUILT_IN_GAMMA_R
:
1341 case BUILT_IN_GAMMAF_R
:
1342 case BUILT_IN_GAMMAL_R
:
1343 case BUILT_IN_LGAMMA_R
:
1344 case BUILT_IN_LGAMMAF_R
:
1345 case BUILT_IN_LGAMMAL_R
:
1347 case BUILT_IN_MODFF
:
1348 case BUILT_IN_MODFL
:
1349 case BUILT_IN_REMQUO
:
1350 case BUILT_IN_REMQUOF
:
1351 case BUILT_IN_REMQUOL
:
1352 case BUILT_IN_SINCOS
:
1353 case BUILT_IN_SINCOSF
:
1354 case BUILT_IN_SINCOSL
:
1355 case BUILT_IN_ASSUME_ALIGNED
:
1356 case BUILT_IN_VA_END
:
1358 /* __sync_* builtins and some OpenMP builtins act as threading
1360 #undef DEF_SYNC_BUILTIN
1361 #define DEF_SYNC_BUILTIN(ENUM, NAME, TYPE, ATTRS) case ENUM:
1362 #include "sync-builtins.def"
1363 #undef DEF_SYNC_BUILTIN
1364 case BUILT_IN_GOMP_ATOMIC_START
:
1365 case BUILT_IN_GOMP_ATOMIC_END
:
1366 case BUILT_IN_GOMP_BARRIER
:
1367 case BUILT_IN_GOMP_TASKWAIT
:
1368 case BUILT_IN_GOMP_CRITICAL_START
:
1369 case BUILT_IN_GOMP_CRITICAL_END
:
1370 case BUILT_IN_GOMP_CRITICAL_NAME_START
:
1371 case BUILT_IN_GOMP_CRITICAL_NAME_END
:
1372 case BUILT_IN_GOMP_LOOP_END
:
1373 case BUILT_IN_GOMP_ORDERED_START
:
1374 case BUILT_IN_GOMP_ORDERED_END
:
1375 case BUILT_IN_GOMP_PARALLEL_END
:
1376 case BUILT_IN_GOMP_SECTIONS_END
:
1377 case BUILT_IN_GOMP_SINGLE_COPY_START
:
1378 case BUILT_IN_GOMP_SINGLE_COPY_END
:
1382 /* Fallthru to general call handling. */;
1385 /* Check if base is a global static variable that is not read
1387 if (callee
!= NULL_TREE
1388 && TREE_CODE (base
) == VAR_DECL
1389 && TREE_STATIC (base
))
1391 struct cgraph_node
*node
= cgraph_get_node (callee
);
1394 /* FIXME: Callee can be an OMP builtin that does not have a call graph
1395 node yet. We should enforce that there are nodes for all decls in the
1396 IL and remove this check instead. */
1398 && (not_read
= ipa_reference_get_not_read_global (node
))
1399 && bitmap_bit_p (not_read
, DECL_UID (base
)))
1403 /* Check if the base variable is call-used. */
1406 if (pt_solution_includes (gimple_call_use_set (call
), base
))
1409 else if ((TREE_CODE (base
) == MEM_REF
1410 || TREE_CODE (base
) == TARGET_MEM_REF
)
1411 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
)
1413 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (TREE_OPERAND (base
, 0));
1417 if (pt_solutions_intersect (gimple_call_use_set (call
), &pi
->pt
))
1423 /* Inspect call arguments for passed-by-value aliases. */
1425 for (i
= 0; i
< gimple_call_num_args (call
); ++i
)
1427 tree op
= gimple_call_arg (call
, i
);
1428 int flags
= gimple_call_arg_flags (call
, i
);
1430 if (flags
& EAF_UNUSED
)
1433 if (TREE_CODE (op
) == WITH_SIZE_EXPR
)
1434 op
= TREE_OPERAND (op
, 0);
1436 if (TREE_CODE (op
) != SSA_NAME
1437 && !is_gimple_min_invariant (op
))
1440 ao_ref_init (&r
, op
);
1441 if (refs_may_alias_p_1 (&r
, ref
, true))
1450 ref_maybe_used_by_call_p (gimple call
, tree ref
)
1454 ao_ref_init (&r
, ref
);
1455 res
= ref_maybe_used_by_call_p_1 (call
, &r
);
1457 ++alias_stats
.ref_maybe_used_by_call_p_may_alias
;
1459 ++alias_stats
.ref_maybe_used_by_call_p_no_alias
;
1464 /* If the statement STMT may use the memory reference REF return
1465 true, otherwise return false. */
1468 ref_maybe_used_by_stmt_p (gimple stmt
, tree ref
)
1470 if (is_gimple_assign (stmt
))
1474 /* All memory assign statements are single. */
1475 if (!gimple_assign_single_p (stmt
))
1478 rhs
= gimple_assign_rhs1 (stmt
);
1479 if (is_gimple_reg (rhs
)
1480 || is_gimple_min_invariant (rhs
)
1481 || gimple_assign_rhs_code (stmt
) == CONSTRUCTOR
)
1484 return refs_may_alias_p (rhs
, ref
);
1486 else if (is_gimple_call (stmt
))
1487 return ref_maybe_used_by_call_p (stmt
, ref
);
1488 else if (gimple_code (stmt
) == GIMPLE_RETURN
)
1490 tree retval
= gimple_return_retval (stmt
);
1493 && TREE_CODE (retval
) != SSA_NAME
1494 && !is_gimple_min_invariant (retval
)
1495 && refs_may_alias_p (retval
, ref
))
1497 /* If ref escapes the function then the return acts as a use. */
1498 base
= get_base_address (ref
);
1501 else if (DECL_P (base
))
1502 return is_global_var (base
);
1503 else if (TREE_CODE (base
) == MEM_REF
1504 || TREE_CODE (base
) == TARGET_MEM_REF
)
1505 return ptr_deref_may_alias_global_p (TREE_OPERAND (base
, 0));
1512 /* If the call in statement CALL may clobber the memory reference REF
1513 return true, otherwise return false. */
1516 call_may_clobber_ref_p_1 (gimple call
, ao_ref
*ref
)
1521 /* If the call is pure or const it cannot clobber anything. */
1522 if (gimple_call_flags (call
)
1523 & (ECF_PURE
|ECF_CONST
|ECF_LOOPING_CONST_OR_PURE
|ECF_NOVOPS
))
1526 base
= ao_ref_base (ref
);
1530 if (TREE_CODE (base
) == SSA_NAME
1531 || CONSTANT_CLASS_P (base
))
1534 /* A call that is not without side-effects might involve volatile
1535 accesses and thus conflicts with all other volatile accesses. */
1536 if (ref
->volatile_p
)
1539 /* If the reference is based on a decl that is not aliased the call
1540 cannot possibly clobber it. */
1542 && !may_be_aliased (base
)
1543 /* But local non-readonly statics can be modified through recursion
1544 or the call may implement a threading barrier which we must
1545 treat as may-def. */
1546 && (TREE_READONLY (base
)
1547 || !is_global_var (base
)))
1550 callee
= gimple_call_fndecl (call
);
1552 /* Handle those builtin functions explicitly that do not act as
1553 escape points. See tree-ssa-structalias.c:find_func_aliases
1554 for the list of builtins we might need to handle here. */
1555 if (callee
!= NULL_TREE
1556 && DECL_BUILT_IN_CLASS (callee
) == BUILT_IN_NORMAL
)
1557 switch (DECL_FUNCTION_CODE (callee
))
1559 /* All the following functions clobber memory pointed to by
1560 their first argument. */
1561 case BUILT_IN_STRCPY
:
1562 case BUILT_IN_STRNCPY
:
1563 case BUILT_IN_MEMCPY
:
1564 case BUILT_IN_MEMMOVE
:
1565 case BUILT_IN_MEMPCPY
:
1566 case BUILT_IN_STPCPY
:
1567 case BUILT_IN_STPNCPY
:
1568 case BUILT_IN_STRCAT
:
1569 case BUILT_IN_STRNCAT
:
1570 case BUILT_IN_MEMSET
:
1571 case BUILT_IN_TM_MEMSET
:
1572 CASE_BUILT_IN_TM_STORE (1):
1573 CASE_BUILT_IN_TM_STORE (2):
1574 CASE_BUILT_IN_TM_STORE (4):
1575 CASE_BUILT_IN_TM_STORE (8):
1576 CASE_BUILT_IN_TM_STORE (FLOAT
):
1577 CASE_BUILT_IN_TM_STORE (DOUBLE
):
1578 CASE_BUILT_IN_TM_STORE (LDOUBLE
):
1579 CASE_BUILT_IN_TM_STORE (M64
):
1580 CASE_BUILT_IN_TM_STORE (M128
):
1581 CASE_BUILT_IN_TM_STORE (M256
):
1582 case BUILT_IN_TM_MEMCPY
:
1583 case BUILT_IN_TM_MEMMOVE
:
1586 tree size
= NULL_TREE
;
1587 /* Don't pass in size for strncat, as the maximum size
1588 is strlen (dest) + n + 1 instead of n, resp.
1589 n + 1 at dest + strlen (dest), but strlen (dest) isn't
1591 if (gimple_call_num_args (call
) == 3
1592 && DECL_FUNCTION_CODE (callee
) != BUILT_IN_STRNCAT
)
1593 size
= gimple_call_arg (call
, 2);
1594 ao_ref_init_from_ptr_and_size (&dref
,
1595 gimple_call_arg (call
, 0),
1597 return refs_may_alias_p_1 (&dref
, ref
, false);
1599 case BUILT_IN_STRCPY_CHK
:
1600 case BUILT_IN_STRNCPY_CHK
:
1601 case BUILT_IN_MEMCPY_CHK
:
1602 case BUILT_IN_MEMMOVE_CHK
:
1603 case BUILT_IN_MEMPCPY_CHK
:
1604 case BUILT_IN_STPCPY_CHK
:
1605 case BUILT_IN_STPNCPY_CHK
:
1606 case BUILT_IN_STRCAT_CHK
:
1607 case BUILT_IN_STRNCAT_CHK
:
1608 case BUILT_IN_MEMSET_CHK
:
1611 tree size
= NULL_TREE
;
1612 /* Don't pass in size for __strncat_chk, as the maximum size
1613 is strlen (dest) + n + 1 instead of n, resp.
1614 n + 1 at dest + strlen (dest), but strlen (dest) isn't
1616 if (gimple_call_num_args (call
) == 4
1617 && DECL_FUNCTION_CODE (callee
) != BUILT_IN_STRNCAT_CHK
)
1618 size
= gimple_call_arg (call
, 2);
1619 ao_ref_init_from_ptr_and_size (&dref
,
1620 gimple_call_arg (call
, 0),
1622 return refs_may_alias_p_1 (&dref
, ref
, false);
1624 case BUILT_IN_BCOPY
:
1627 tree size
= gimple_call_arg (call
, 2);
1628 ao_ref_init_from_ptr_and_size (&dref
,
1629 gimple_call_arg (call
, 1),
1631 return refs_may_alias_p_1 (&dref
, ref
, false);
1633 /* Allocating memory does not have any side-effects apart from
1634 being the definition point for the pointer. */
1635 case BUILT_IN_MALLOC
:
1636 case BUILT_IN_CALLOC
:
1637 case BUILT_IN_STRDUP
:
1638 case BUILT_IN_STRNDUP
:
1639 /* Unix98 specifies that errno is set on allocation failure. */
1641 && targetm
.ref_may_alias_errno (ref
))
1644 case BUILT_IN_STACK_SAVE
:
1645 case BUILT_IN_ALLOCA
:
1646 case BUILT_IN_ALLOCA_WITH_ALIGN
:
1647 case BUILT_IN_ASSUME_ALIGNED
:
1649 /* Freeing memory kills the pointed-to memory. More importantly
1650 the call has to serve as a barrier for moving loads and stores
1653 case BUILT_IN_VA_END
:
1655 tree ptr
= gimple_call_arg (call
, 0);
1656 return ptr_deref_may_alias_ref_p_1 (ptr
, ref
);
1658 case BUILT_IN_GAMMA_R
:
1659 case BUILT_IN_GAMMAF_R
:
1660 case BUILT_IN_GAMMAL_R
:
1661 case BUILT_IN_LGAMMA_R
:
1662 case BUILT_IN_LGAMMAF_R
:
1663 case BUILT_IN_LGAMMAL_R
:
1665 tree out
= gimple_call_arg (call
, 1);
1666 if (ptr_deref_may_alias_ref_p_1 (out
, ref
))
1668 if (flag_errno_math
)
1672 case BUILT_IN_FREXP
:
1673 case BUILT_IN_FREXPF
:
1674 case BUILT_IN_FREXPL
:
1676 case BUILT_IN_MODFF
:
1677 case BUILT_IN_MODFL
:
1679 tree out
= gimple_call_arg (call
, 1);
1680 return ptr_deref_may_alias_ref_p_1 (out
, ref
);
1682 case BUILT_IN_REMQUO
:
1683 case BUILT_IN_REMQUOF
:
1684 case BUILT_IN_REMQUOL
:
1686 tree out
= gimple_call_arg (call
, 2);
1687 if (ptr_deref_may_alias_ref_p_1 (out
, ref
))
1689 if (flag_errno_math
)
1693 case BUILT_IN_SINCOS
:
1694 case BUILT_IN_SINCOSF
:
1695 case BUILT_IN_SINCOSL
:
1697 tree sin
= gimple_call_arg (call
, 1);
1698 tree cos
= gimple_call_arg (call
, 2);
1699 return (ptr_deref_may_alias_ref_p_1 (sin
, ref
)
1700 || ptr_deref_may_alias_ref_p_1 (cos
, ref
));
1702 /* __sync_* builtins and some OpenMP builtins act as threading
1704 #undef DEF_SYNC_BUILTIN
1705 #define DEF_SYNC_BUILTIN(ENUM, NAME, TYPE, ATTRS) case ENUM:
1706 #include "sync-builtins.def"
1707 #undef DEF_SYNC_BUILTIN
1708 case BUILT_IN_GOMP_ATOMIC_START
:
1709 case BUILT_IN_GOMP_ATOMIC_END
:
1710 case BUILT_IN_GOMP_BARRIER
:
1711 case BUILT_IN_GOMP_TASKWAIT
:
1712 case BUILT_IN_GOMP_CRITICAL_START
:
1713 case BUILT_IN_GOMP_CRITICAL_END
:
1714 case BUILT_IN_GOMP_CRITICAL_NAME_START
:
1715 case BUILT_IN_GOMP_CRITICAL_NAME_END
:
1716 case BUILT_IN_GOMP_LOOP_END
:
1717 case BUILT_IN_GOMP_ORDERED_START
:
1718 case BUILT_IN_GOMP_ORDERED_END
:
1719 case BUILT_IN_GOMP_PARALLEL_END
:
1720 case BUILT_IN_GOMP_SECTIONS_END
:
1721 case BUILT_IN_GOMP_SINGLE_COPY_START
:
1722 case BUILT_IN_GOMP_SINGLE_COPY_END
:
1725 /* Fallthru to general call handling. */;
1728 /* Check if base is a global static variable that is not written
1730 if (callee
!= NULL_TREE
1731 && TREE_CODE (base
) == VAR_DECL
1732 && TREE_STATIC (base
))
1734 struct cgraph_node
*node
= cgraph_get_node (callee
);
1738 && (not_written
= ipa_reference_get_not_written_global (node
))
1739 && bitmap_bit_p (not_written
, DECL_UID (base
)))
1743 /* Check if the base variable is call-clobbered. */
1745 return pt_solution_includes (gimple_call_clobber_set (call
), base
);
1746 else if ((TREE_CODE (base
) == MEM_REF
1747 || TREE_CODE (base
) == TARGET_MEM_REF
)
1748 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
)
1750 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (TREE_OPERAND (base
, 0));
1754 return pt_solutions_intersect (gimple_call_clobber_set (call
), &pi
->pt
);
1760 /* If the call in statement CALL may clobber the memory reference REF
1761 return true, otherwise return false. */
1764 call_may_clobber_ref_p (gimple call
, tree ref
)
1768 ao_ref_init (&r
, ref
);
1769 res
= call_may_clobber_ref_p_1 (call
, &r
);
1771 ++alias_stats
.call_may_clobber_ref_p_may_alias
;
1773 ++alias_stats
.call_may_clobber_ref_p_no_alias
;
1778 /* If the statement STMT may clobber the memory reference REF return true,
1779 otherwise return false. */
1782 stmt_may_clobber_ref_p_1 (gimple stmt
, ao_ref
*ref
)
1784 if (is_gimple_call (stmt
))
1786 tree lhs
= gimple_call_lhs (stmt
);
1788 && TREE_CODE (lhs
) != SSA_NAME
)
1791 ao_ref_init (&r
, lhs
);
1792 if (refs_may_alias_p_1 (ref
, &r
, true))
1796 return call_may_clobber_ref_p_1 (stmt
, ref
);
1798 else if (gimple_assign_single_p (stmt
))
1800 tree lhs
= gimple_assign_lhs (stmt
);
1801 if (TREE_CODE (lhs
) != SSA_NAME
)
1804 ao_ref_init (&r
, lhs
);
1805 return refs_may_alias_p_1 (ref
, &r
, true);
1808 else if (gimple_code (stmt
) == GIMPLE_ASM
)
1815 stmt_may_clobber_ref_p (gimple stmt
, tree ref
)
1818 ao_ref_init (&r
, ref
);
1819 return stmt_may_clobber_ref_p_1 (stmt
, &r
);
1822 /* If STMT kills the memory reference REF return true, otherwise
1826 stmt_kills_ref_p_1 (gimple stmt
, ao_ref
*ref
)
1828 /* For a must-alias check we need to be able to constrain
1829 the access properly. */
1831 if (ref
->max_size
== -1)
1834 if (gimple_has_lhs (stmt
)
1835 && TREE_CODE (gimple_get_lhs (stmt
)) != SSA_NAME
1836 /* The assignment is not necessarily carried out if it can throw
1837 and we can catch it in the current function where we could inspect
1839 ??? We only need to care about the RHS throwing. For aggregate
1840 assignments or similar calls and non-call exceptions the LHS
1841 might throw as well. */
1842 && !stmt_can_throw_internal (stmt
))
1844 tree base
, lhs
= gimple_get_lhs (stmt
);
1845 HOST_WIDE_INT size
, offset
, max_size
;
1846 base
= get_ref_base_and_extent (lhs
, &offset
, &size
, &max_size
);
1847 /* We can get MEM[symbol: sZ, index: D.8862_1] here,
1848 so base == ref->base does not always hold. */
1849 if (base
== ref
->base
)
1851 /* For a must-alias check we need to be able to constrain
1852 the access properly. */
1853 if (size
!= -1 && size
== max_size
)
1855 if (offset
<= ref
->offset
1856 && offset
+ size
>= ref
->offset
+ ref
->max_size
)
1862 if (is_gimple_call (stmt
))
1864 tree callee
= gimple_call_fndecl (stmt
);
1865 if (callee
!= NULL_TREE
1866 && DECL_BUILT_IN_CLASS (callee
) == BUILT_IN_NORMAL
)
1867 switch (DECL_FUNCTION_CODE (callee
))
1869 case BUILT_IN_MEMCPY
:
1870 case BUILT_IN_MEMPCPY
:
1871 case BUILT_IN_MEMMOVE
:
1872 case BUILT_IN_MEMSET
:
1873 case BUILT_IN_MEMCPY_CHK
:
1874 case BUILT_IN_MEMPCPY_CHK
:
1875 case BUILT_IN_MEMMOVE_CHK
:
1876 case BUILT_IN_MEMSET_CHK
:
1878 tree dest
= gimple_call_arg (stmt
, 0);
1879 tree len
= gimple_call_arg (stmt
, 2);
1880 tree base
= NULL_TREE
;
1881 HOST_WIDE_INT offset
= 0;
1882 if (!host_integerp (len
, 0))
1884 if (TREE_CODE (dest
) == ADDR_EXPR
)
1885 base
= get_addr_base_and_unit_offset (TREE_OPERAND (dest
, 0),
1887 else if (TREE_CODE (dest
) == SSA_NAME
)
1890 && base
== ao_ref_base (ref
))
1892 HOST_WIDE_INT size
= TREE_INT_CST_LOW (len
);
1893 if (offset
<= ref
->offset
/ BITS_PER_UNIT
1895 >= ((ref
->offset
+ ref
->max_size
+ BITS_PER_UNIT
- 1)
1902 case BUILT_IN_VA_END
:
1904 tree ptr
= gimple_call_arg (stmt
, 0);
1905 if (TREE_CODE (ptr
) == ADDR_EXPR
)
1907 tree base
= ao_ref_base (ref
);
1908 if (TREE_OPERAND (ptr
, 0) == base
)
1921 stmt_kills_ref_p (gimple stmt
, tree ref
)
1924 ao_ref_init (&r
, ref
);
1925 return stmt_kills_ref_p_1 (stmt
, &r
);
1929 /* Walk the virtual use-def chain of VUSE until hitting the virtual operand
1930 TARGET or a statement clobbering the memory reference REF in which
1931 case false is returned. The walk starts with VUSE, one argument of PHI. */
1934 maybe_skip_until (gimple phi
, tree target
, ao_ref
*ref
,
1935 tree vuse
, bitmap
*visited
)
1937 basic_block bb
= gimple_bb (phi
);
1940 *visited
= BITMAP_ALLOC (NULL
);
1942 bitmap_set_bit (*visited
, SSA_NAME_VERSION (PHI_RESULT (phi
)));
1944 /* Walk until we hit the target. */
1945 while (vuse
!= target
)
1947 gimple def_stmt
= SSA_NAME_DEF_STMT (vuse
);
1948 /* Recurse for PHI nodes. */
1949 if (gimple_code (def_stmt
) == GIMPLE_PHI
)
1951 /* An already visited PHI node ends the walk successfully. */
1952 if (bitmap_bit_p (*visited
, SSA_NAME_VERSION (PHI_RESULT (def_stmt
))))
1954 vuse
= get_continuation_for_phi (def_stmt
, ref
, visited
);
1959 /* A clobbering statement or the end of the IL ends it failing. */
1960 else if (gimple_nop_p (def_stmt
)
1961 || stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
1963 /* If we reach a new basic-block see if we already skipped it
1964 in a previous walk that ended successfully. */
1965 if (gimple_bb (def_stmt
) != bb
)
1967 if (!bitmap_set_bit (*visited
, SSA_NAME_VERSION (vuse
)))
1969 bb
= gimple_bb (def_stmt
);
1971 vuse
= gimple_vuse (def_stmt
);
1976 /* For two PHI arguments ARG0 and ARG1 try to skip non-aliasing code
1977 until we hit the phi argument definition that dominates the other one.
1978 Return that, or NULL_TREE if there is no such definition. */
1981 get_continuation_for_phi_1 (gimple phi
, tree arg0
, tree arg1
,
1982 ao_ref
*ref
, bitmap
*visited
)
1984 gimple def0
= SSA_NAME_DEF_STMT (arg0
);
1985 gimple def1
= SSA_NAME_DEF_STMT (arg1
);
1990 else if (gimple_nop_p (def0
)
1991 || (!gimple_nop_p (def1
)
1992 && dominated_by_p (CDI_DOMINATORS
,
1993 gimple_bb (def1
), gimple_bb (def0
))))
1995 if (maybe_skip_until (phi
, arg0
, ref
, arg1
, visited
))
1998 else if (gimple_nop_p (def1
)
1999 || dominated_by_p (CDI_DOMINATORS
,
2000 gimple_bb (def0
), gimple_bb (def1
)))
2002 if (maybe_skip_until (phi
, arg1
, ref
, arg0
, visited
))
2005 /* Special case of a diamond:
2007 goto (cond) ? L1 : L2
2008 L1: store1 = ... #MEM_2 = vuse(MEM_1)
2010 L2: store2 = ... #MEM_3 = vuse(MEM_1)
2011 L3: MEM_4 = PHI<MEM_2, MEM_3>
2012 We were called with the PHI at L3, MEM_2 and MEM_3 don't
2013 dominate each other, but still we can easily skip this PHI node
2014 if we recognize that the vuse MEM operand is the same for both,
2015 and that we can skip both statements (they don't clobber us).
2016 This is still linear. Don't use maybe_skip_until, that might
2017 potentially be slow. */
2018 else if ((common_vuse
= gimple_vuse (def0
))
2019 && common_vuse
== gimple_vuse (def1
))
2021 if (!stmt_may_clobber_ref_p_1 (def0
, ref
)
2022 && !stmt_may_clobber_ref_p_1 (def1
, ref
))
2030 /* Starting from a PHI node for the virtual operand of the memory reference
2031 REF find a continuation virtual operand that allows to continue walking
2032 statements dominating PHI skipping only statements that cannot possibly
2033 clobber REF. Returns NULL_TREE if no suitable virtual operand can
2037 get_continuation_for_phi (gimple phi
, ao_ref
*ref
, bitmap
*visited
)
2039 unsigned nargs
= gimple_phi_num_args (phi
);
2041 /* Through a single-argument PHI we can simply look through. */
2043 return PHI_ARG_DEF (phi
, 0);
2045 /* For two or more arguments try to pairwise skip non-aliasing code
2046 until we hit the phi argument definition that dominates the other one. */
2047 else if (nargs
>= 2)
2052 /* Find a candidate for the virtual operand which definition
2053 dominates those of all others. */
2054 arg0
= PHI_ARG_DEF (phi
, 0);
2055 if (!SSA_NAME_IS_DEFAULT_DEF (arg0
))
2056 for (i
= 1; i
< nargs
; ++i
)
2058 arg1
= PHI_ARG_DEF (phi
, i
);
2059 if (SSA_NAME_IS_DEFAULT_DEF (arg1
))
2064 if (dominated_by_p (CDI_DOMINATORS
,
2065 gimple_bb (SSA_NAME_DEF_STMT (arg0
)),
2066 gimple_bb (SSA_NAME_DEF_STMT (arg1
))))
2070 /* Then pairwise reduce against the found candidate. */
2071 for (i
= 0; i
< nargs
; ++i
)
2073 arg1
= PHI_ARG_DEF (phi
, i
);
2074 arg0
= get_continuation_for_phi_1 (phi
, arg0
, arg1
, ref
, visited
);
2085 /* Based on the memory reference REF and its virtual use VUSE call
2086 WALKER for each virtual use that is equivalent to VUSE, including VUSE
2087 itself. That is, for each virtual use for which its defining statement
2088 does not clobber REF.
2090 WALKER is called with REF, the current virtual use and DATA. If
2091 WALKER returns non-NULL the walk stops and its result is returned.
2092 At the end of a non-successful walk NULL is returned.
2094 TRANSLATE if non-NULL is called with a pointer to REF, the virtual
2095 use which definition is a statement that may clobber REF and DATA.
2096 If TRANSLATE returns (void *)-1 the walk stops and NULL is returned.
2097 If TRANSLATE returns non-NULL the walk stops and its result is returned.
2098 If TRANSLATE returns NULL the walk continues and TRANSLATE is supposed
2099 to adjust REF and *DATA to make that valid.
2101 TODO: Cache the vector of equivalent vuses per ref, vuse pair. */
2104 walk_non_aliased_vuses (ao_ref
*ref
, tree vuse
,
2105 void *(*walker
)(ao_ref
*, tree
, void *),
2106 void *(*translate
)(ao_ref
*, tree
, void *), void *data
)
2108 bitmap visited
= NULL
;
2111 timevar_push (TV_ALIAS_STMT_WALK
);
2117 /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */
2118 res
= (*walker
) (ref
, vuse
, data
);
2122 def_stmt
= SSA_NAME_DEF_STMT (vuse
);
2123 if (gimple_nop_p (def_stmt
))
2125 else if (gimple_code (def_stmt
) == GIMPLE_PHI
)
2126 vuse
= get_continuation_for_phi (def_stmt
, ref
, &visited
);
2129 if (stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
2133 res
= (*translate
) (ref
, vuse
, data
);
2134 /* Failed lookup and translation. */
2135 if (res
== (void *)-1)
2140 /* Lookup succeeded. */
2141 else if (res
!= NULL
)
2143 /* Translation succeeded, continue walking. */
2145 vuse
= gimple_vuse (def_stmt
);
2151 BITMAP_FREE (visited
);
2153 timevar_pop (TV_ALIAS_STMT_WALK
);
2159 /* Based on the memory reference REF call WALKER for each vdef which
2160 defining statement may clobber REF, starting with VDEF. If REF
2161 is NULL_TREE, each defining statement is visited.
2163 WALKER is called with REF, the current vdef and DATA. If WALKER
2164 returns true the walk is stopped, otherwise it continues.
2166 At PHI nodes walk_aliased_vdefs forks into one walk for reach
2167 PHI argument (but only one walk continues on merge points), the
2168 return value is true if any of the walks was successful.
2170 The function returns the number of statements walked. */
2173 walk_aliased_vdefs_1 (ao_ref
*ref
, tree vdef
,
2174 bool (*walker
)(ao_ref
*, tree
, void *), void *data
,
2175 bitmap
*visited
, unsigned int cnt
)
2179 gimple def_stmt
= SSA_NAME_DEF_STMT (vdef
);
2182 && !bitmap_set_bit (*visited
, SSA_NAME_VERSION (vdef
)))
2185 if (gimple_nop_p (def_stmt
))
2187 else if (gimple_code (def_stmt
) == GIMPLE_PHI
)
2191 *visited
= BITMAP_ALLOC (NULL
);
2192 for (i
= 0; i
< gimple_phi_num_args (def_stmt
); ++i
)
2193 cnt
+= walk_aliased_vdefs_1 (ref
, gimple_phi_arg_def (def_stmt
, i
),
2194 walker
, data
, visited
, 0);
2198 /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */
2201 || stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
2202 && (*walker
) (ref
, vdef
, data
))
2205 vdef
= gimple_vuse (def_stmt
);
2211 walk_aliased_vdefs (ao_ref
*ref
, tree vdef
,
2212 bool (*walker
)(ao_ref
*, tree
, void *), void *data
,
2215 bitmap local_visited
= NULL
;
2218 timevar_push (TV_ALIAS_STMT_WALK
);
2220 ret
= walk_aliased_vdefs_1 (ref
, vdef
, walker
, data
,
2221 visited
? visited
: &local_visited
, 0);
2223 BITMAP_FREE (local_visited
);
2225 timevar_pop (TV_ALIAS_STMT_WALK
);