SUBREG_PROMOTED_VAR_P handling in expand_direct_optab_fn
[official-gcc.git] / gcc / alias.c
blobcb57c6a10ff125a128110e06822d6ff6bb4a37fe
1 /* Alias analysis for GNU C
2 Copyright (C) 1997-2017 Free Software Foundation, Inc.
3 Contributed by John Carr (jfc@mit.edu).
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 3, or (at your option) any later
10 version.
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 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/>. */
21 #include "config.h"
22 #include "system.h"
23 #include "coretypes.h"
24 #include "backend.h"
25 #include "target.h"
26 #include "rtl.h"
27 #include "tree.h"
28 #include "gimple.h"
29 #include "df.h"
30 #include "memmodel.h"
31 #include "tm_p.h"
32 #include "gimple-ssa.h"
33 #include "emit-rtl.h"
34 #include "alias.h"
35 #include "fold-const.h"
36 #include "varasm.h"
37 #include "cselib.h"
38 #include "langhooks.h"
39 #include "cfganal.h"
40 #include "rtl-iter.h"
41 #include "cgraph.h"
43 /* The aliasing API provided here solves related but different problems:
45 Say there exists (in c)
47 struct X {
48 struct Y y1;
49 struct Z z2;
50 } x1, *px1, *px2;
52 struct Y y2, *py;
53 struct Z z2, *pz;
56 py = &x1.y1;
57 px2 = &x1;
59 Consider the four questions:
61 Can a store to x1 interfere with px2->y1?
62 Can a store to x1 interfere with px2->z2?
63 Can a store to x1 change the value pointed to by with py?
64 Can a store to x1 change the value pointed to by with pz?
66 The answer to these questions can be yes, yes, yes, and maybe.
68 The first two questions can be answered with a simple examination
69 of the type system. If structure X contains a field of type Y then
70 a store through a pointer to an X can overwrite any field that is
71 contained (recursively) in an X (unless we know that px1 != px2).
73 The last two questions can be solved in the same way as the first
74 two questions but this is too conservative. The observation is
75 that in some cases we can know which (if any) fields are addressed
76 and if those addresses are used in bad ways. This analysis may be
77 language specific. In C, arbitrary operations may be applied to
78 pointers. However, there is some indication that this may be too
79 conservative for some C++ types.
81 The pass ipa-type-escape does this analysis for the types whose
82 instances do not escape across the compilation boundary.
84 Historically in GCC, these two problems were combined and a single
85 data structure that was used to represent the solution to these
86 problems. We now have two similar but different data structures,
87 The data structure to solve the last two questions is similar to
88 the first, but does not contain the fields whose address are never
89 taken. For types that do escape the compilation unit, the data
90 structures will have identical information.
93 /* The alias sets assigned to MEMs assist the back-end in determining
94 which MEMs can alias which other MEMs. In general, two MEMs in
95 different alias sets cannot alias each other, with one important
96 exception. Consider something like:
98 struct S { int i; double d; };
100 a store to an `S' can alias something of either type `int' or type
101 `double'. (However, a store to an `int' cannot alias a `double'
102 and vice versa.) We indicate this via a tree structure that looks
103 like:
104 struct S
107 |/_ _\|
108 int double
110 (The arrows are directed and point downwards.)
111 In this situation we say the alias set for `struct S' is the
112 `superset' and that those for `int' and `double' are `subsets'.
114 To see whether two alias sets can point to the same memory, we must
115 see if either alias set is a subset of the other. We need not trace
116 past immediate descendants, however, since we propagate all
117 grandchildren up one level.
119 Alias set zero is implicitly a superset of all other alias sets.
120 However, this is no actual entry for alias set zero. It is an
121 error to attempt to explicitly construct a subset of zero. */
123 struct alias_set_hash : int_hash <int, INT_MIN, INT_MIN + 1> {};
125 struct GTY(()) alias_set_entry {
126 /* The alias set number, as stored in MEM_ALIAS_SET. */
127 alias_set_type alias_set;
129 /* Nonzero if would have a child of zero: this effectively makes this
130 alias set the same as alias set zero. */
131 bool has_zero_child;
132 /* Nonzero if alias set corresponds to pointer type itself (i.e. not to
133 aggregate contaiing pointer.
134 This is used for a special case where we need an universal pointer type
135 compatible with all other pointer types. */
136 bool is_pointer;
137 /* Nonzero if is_pointer or if one of childs have has_pointer set. */
138 bool has_pointer;
140 /* The children of the alias set. These are not just the immediate
141 children, but, in fact, all descendants. So, if we have:
143 struct T { struct S s; float f; }
145 continuing our example above, the children here will be all of
146 `int', `double', `float', and `struct S'. */
147 hash_map<alias_set_hash, int> *children;
150 static int rtx_equal_for_memref_p (const_rtx, const_rtx);
151 static int memrefs_conflict_p (int, rtx, int, rtx, HOST_WIDE_INT);
152 static void record_set (rtx, const_rtx, void *);
153 static int base_alias_check (rtx, rtx, rtx, rtx, machine_mode,
154 machine_mode);
155 static rtx find_base_value (rtx);
156 static int mems_in_disjoint_alias_sets_p (const_rtx, const_rtx);
157 static alias_set_entry *get_alias_set_entry (alias_set_type);
158 static tree decl_for_component_ref (tree);
159 static int write_dependence_p (const_rtx,
160 const_rtx, machine_mode, rtx,
161 bool, bool, bool);
162 static int compare_base_symbol_refs (const_rtx, const_rtx);
164 static void memory_modified_1 (rtx, const_rtx, void *);
166 /* Query statistics for the different low-level disambiguators.
167 A high-level query may trigger multiple of them. */
169 static struct {
170 unsigned long long num_alias_zero;
171 unsigned long long num_same_alias_set;
172 unsigned long long num_same_objects;
173 unsigned long long num_volatile;
174 unsigned long long num_dag;
175 unsigned long long num_universal;
176 unsigned long long num_disambiguated;
177 } alias_stats;
180 /* Set up all info needed to perform alias analysis on memory references. */
182 /* Returns the size in bytes of the mode of X. */
183 #define SIZE_FOR_MODE(X) (GET_MODE_SIZE (GET_MODE (X)))
185 /* Cap the number of passes we make over the insns propagating alias
186 information through set chains.
187 ??? 10 is a completely arbitrary choice. This should be based on the
188 maximum loop depth in the CFG, but we do not have this information
189 available (even if current_loops _is_ available). */
190 #define MAX_ALIAS_LOOP_PASSES 10
192 /* reg_base_value[N] gives an address to which register N is related.
193 If all sets after the first add or subtract to the current value
194 or otherwise modify it so it does not point to a different top level
195 object, reg_base_value[N] is equal to the address part of the source
196 of the first set.
198 A base address can be an ADDRESS, SYMBOL_REF, or LABEL_REF. ADDRESS
199 expressions represent three types of base:
201 1. incoming arguments. There is just one ADDRESS to represent all
202 arguments, since we do not know at this level whether accesses
203 based on different arguments can alias. The ADDRESS has id 0.
205 2. stack_pointer_rtx, frame_pointer_rtx, hard_frame_pointer_rtx
206 (if distinct from frame_pointer_rtx) and arg_pointer_rtx.
207 Each of these rtxes has a separate ADDRESS associated with it,
208 each with a negative id.
210 GCC is (and is required to be) precise in which register it
211 chooses to access a particular region of stack. We can therefore
212 assume that accesses based on one of these rtxes do not alias
213 accesses based on another of these rtxes.
215 3. bases that are derived from malloc()ed memory (REG_NOALIAS).
216 Each such piece of memory has a separate ADDRESS associated
217 with it, each with an id greater than 0.
219 Accesses based on one ADDRESS do not alias accesses based on other
220 ADDRESSes. Accesses based on ADDRESSes in groups (2) and (3) do not
221 alias globals either; the ADDRESSes have Pmode to indicate this.
222 The ADDRESS in group (1) _may_ alias globals; it has VOIDmode to
223 indicate this. */
225 static GTY(()) vec<rtx, va_gc> *reg_base_value;
226 static rtx *new_reg_base_value;
228 /* The single VOIDmode ADDRESS that represents all argument bases.
229 It has id 0. */
230 static GTY(()) rtx arg_base_value;
232 /* Used to allocate unique ids to each REG_NOALIAS ADDRESS. */
233 static int unique_id;
235 /* We preserve the copy of old array around to avoid amount of garbage
236 produced. About 8% of garbage produced were attributed to this
237 array. */
238 static GTY((deletable)) vec<rtx, va_gc> *old_reg_base_value;
240 /* Values of XINT (address, 0) of Pmode ADDRESS rtxes for special
241 registers. */
242 #define UNIQUE_BASE_VALUE_SP -1
243 #define UNIQUE_BASE_VALUE_ARGP -2
244 #define UNIQUE_BASE_VALUE_FP -3
245 #define UNIQUE_BASE_VALUE_HFP -4
247 #define static_reg_base_value \
248 (this_target_rtl->x_static_reg_base_value)
250 #define REG_BASE_VALUE(X) \
251 (REGNO (X) < vec_safe_length (reg_base_value) \
252 ? (*reg_base_value)[REGNO (X)] : 0)
254 /* Vector indexed by N giving the initial (unchanging) value known for
255 pseudo-register N. This vector is initialized in init_alias_analysis,
256 and does not change until end_alias_analysis is called. */
257 static GTY(()) vec<rtx, va_gc> *reg_known_value;
259 /* Vector recording for each reg_known_value whether it is due to a
260 REG_EQUIV note. Future passes (viz., reload) may replace the
261 pseudo with the equivalent expression and so we account for the
262 dependences that would be introduced if that happens.
264 The REG_EQUIV notes created in assign_parms may mention the arg
265 pointer, and there are explicit insns in the RTL that modify the
266 arg pointer. Thus we must ensure that such insns don't get
267 scheduled across each other because that would invalidate the
268 REG_EQUIV notes. One could argue that the REG_EQUIV notes are
269 wrong, but solving the problem in the scheduler will likely give
270 better code, so we do it here. */
271 static sbitmap reg_known_equiv_p;
273 /* True when scanning insns from the start of the rtl to the
274 NOTE_INSN_FUNCTION_BEG note. */
275 static bool copying_arguments;
278 /* The splay-tree used to store the various alias set entries. */
279 static GTY (()) vec<alias_set_entry *, va_gc> *alias_sets;
281 /* Build a decomposed reference object for querying the alias-oracle
282 from the MEM rtx and store it in *REF.
283 Returns false if MEM is not suitable for the alias-oracle. */
285 static bool
286 ao_ref_from_mem (ao_ref *ref, const_rtx mem)
288 tree expr = MEM_EXPR (mem);
289 tree base;
291 if (!expr)
292 return false;
294 ao_ref_init (ref, expr);
296 /* Get the base of the reference and see if we have to reject or
297 adjust it. */
298 base = ao_ref_base (ref);
299 if (base == NULL_TREE)
300 return false;
302 /* The tree oracle doesn't like bases that are neither decls
303 nor indirect references of SSA names. */
304 if (!(DECL_P (base)
305 || (TREE_CODE (base) == MEM_REF
306 && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME)
307 || (TREE_CODE (base) == TARGET_MEM_REF
308 && TREE_CODE (TMR_BASE (base)) == SSA_NAME)))
309 return false;
311 /* If this is a reference based on a partitioned decl replace the
312 base with a MEM_REF of the pointer representative we
313 created during stack slot partitioning. */
314 if (VAR_P (base)
315 && ! is_global_var (base)
316 && cfun->gimple_df->decls_to_pointers != NULL)
318 tree *namep = cfun->gimple_df->decls_to_pointers->get (base);
319 if (namep)
320 ref->base = build_simple_mem_ref (*namep);
323 ref->ref_alias_set = MEM_ALIAS_SET (mem);
325 /* If MEM_OFFSET or MEM_SIZE are unknown what we got from MEM_EXPR
326 is conservative, so trust it. */
327 if (!MEM_OFFSET_KNOWN_P (mem)
328 || !MEM_SIZE_KNOWN_P (mem))
329 return true;
331 /* If MEM_OFFSET/MEM_SIZE get us outside of ref->offset/ref->max_size
332 drop ref->ref. */
333 if (MEM_OFFSET (mem) < 0
334 || (ref->max_size != -1
335 && ((MEM_OFFSET (mem) + MEM_SIZE (mem)) * BITS_PER_UNIT
336 > ref->max_size)))
337 ref->ref = NULL_TREE;
339 /* Refine size and offset we got from analyzing MEM_EXPR by using
340 MEM_SIZE and MEM_OFFSET. */
342 ref->offset += MEM_OFFSET (mem) * BITS_PER_UNIT;
343 ref->size = MEM_SIZE (mem) * BITS_PER_UNIT;
345 /* The MEM may extend into adjacent fields, so adjust max_size if
346 necessary. */
347 if (ref->max_size != -1
348 && ref->size > ref->max_size)
349 ref->max_size = ref->size;
351 /* If MEM_OFFSET and MEM_SIZE get us outside of the base object of
352 the MEM_EXPR punt. This happens for STRICT_ALIGNMENT targets a lot. */
353 if (MEM_EXPR (mem) != get_spill_slot_decl (false)
354 && (ref->offset < 0
355 || (DECL_P (ref->base)
356 && (DECL_SIZE (ref->base) == NULL_TREE
357 || TREE_CODE (DECL_SIZE (ref->base)) != INTEGER_CST
358 || wi::ltu_p (wi::to_offset (DECL_SIZE (ref->base)),
359 ref->offset + ref->size)))))
360 return false;
362 return true;
365 /* Query the alias-oracle on whether the two memory rtx X and MEM may
366 alias. If TBAA_P is set also apply TBAA. Returns true if the
367 two rtxen may alias, false otherwise. */
369 static bool
370 rtx_refs_may_alias_p (const_rtx x, const_rtx mem, bool tbaa_p)
372 ao_ref ref1, ref2;
374 if (!ao_ref_from_mem (&ref1, x)
375 || !ao_ref_from_mem (&ref2, mem))
376 return true;
378 return refs_may_alias_p_1 (&ref1, &ref2,
379 tbaa_p
380 && MEM_ALIAS_SET (x) != 0
381 && MEM_ALIAS_SET (mem) != 0);
384 /* Returns a pointer to the alias set entry for ALIAS_SET, if there is
385 such an entry, or NULL otherwise. */
387 static inline alias_set_entry *
388 get_alias_set_entry (alias_set_type alias_set)
390 return (*alias_sets)[alias_set];
393 /* Returns nonzero if the alias sets for MEM1 and MEM2 are such that
394 the two MEMs cannot alias each other. */
396 static inline int
397 mems_in_disjoint_alias_sets_p (const_rtx mem1, const_rtx mem2)
399 return (flag_strict_aliasing
400 && ! alias_sets_conflict_p (MEM_ALIAS_SET (mem1),
401 MEM_ALIAS_SET (mem2)));
404 /* Return true if the first alias set is a subset of the second. */
406 bool
407 alias_set_subset_of (alias_set_type set1, alias_set_type set2)
409 alias_set_entry *ase2;
411 /* Disable TBAA oracle with !flag_strict_aliasing. */
412 if (!flag_strict_aliasing)
413 return true;
415 /* Everything is a subset of the "aliases everything" set. */
416 if (set2 == 0)
417 return true;
419 /* Check if set1 is a subset of set2. */
420 ase2 = get_alias_set_entry (set2);
421 if (ase2 != 0
422 && (ase2->has_zero_child
423 || (ase2->children && ase2->children->get (set1))))
424 return true;
426 /* As a special case we consider alias set of "void *" to be both subset
427 and superset of every alias set of a pointer. This extra symmetry does
428 not matter for alias_sets_conflict_p but it makes aliasing_component_refs_p
429 to return true on the following testcase:
431 void *ptr;
432 char **ptr2=(char **)&ptr;
433 *ptr2 = ...
435 Additionally if a set contains universal pointer, we consider every pointer
436 to be a subset of it, but we do not represent this explicitely - doing so
437 would require us to update transitive closure each time we introduce new
438 pointer type. This makes aliasing_component_refs_p to return true
439 on the following testcase:
441 struct a {void *ptr;}
442 char **ptr = (char **)&a.ptr;
443 ptr = ...
445 This makes void * truly universal pointer type. See pointer handling in
446 get_alias_set for more details. */
447 if (ase2 && ase2->has_pointer)
449 alias_set_entry *ase1 = get_alias_set_entry (set1);
451 if (ase1 && ase1->is_pointer)
453 alias_set_type voidptr_set = TYPE_ALIAS_SET (ptr_type_node);
454 /* If one is ptr_type_node and other is pointer, then we consider
455 them subset of each other. */
456 if (set1 == voidptr_set || set2 == voidptr_set)
457 return true;
458 /* If SET2 contains universal pointer's alias set, then we consdier
459 every (non-universal) pointer. */
460 if (ase2->children && set1 != voidptr_set
461 && ase2->children->get (voidptr_set))
462 return true;
465 return false;
468 /* Return 1 if the two specified alias sets may conflict. */
471 alias_sets_conflict_p (alias_set_type set1, alias_set_type set2)
473 alias_set_entry *ase1;
474 alias_set_entry *ase2;
476 /* The easy case. */
477 if (alias_sets_must_conflict_p (set1, set2))
478 return 1;
480 /* See if the first alias set is a subset of the second. */
481 ase1 = get_alias_set_entry (set1);
482 if (ase1 != 0
483 && ase1->children && ase1->children->get (set2))
485 ++alias_stats.num_dag;
486 return 1;
489 /* Now do the same, but with the alias sets reversed. */
490 ase2 = get_alias_set_entry (set2);
491 if (ase2 != 0
492 && ase2->children && ase2->children->get (set1))
494 ++alias_stats.num_dag;
495 return 1;
498 /* We want void * to be compatible with any other pointer without
499 really dropping it to alias set 0. Doing so would make it
500 compatible with all non-pointer types too.
502 This is not strictly necessary by the C/C++ language
503 standards, but avoids common type punning mistakes. In
504 addition to that, we need the existence of such universal
505 pointer to implement Fortran's C_PTR type (which is defined as
506 type compatible with all C pointers). */
507 if (ase1 && ase2 && ase1->has_pointer && ase2->has_pointer)
509 alias_set_type voidptr_set = TYPE_ALIAS_SET (ptr_type_node);
511 /* If one of the sets corresponds to universal pointer,
512 we consider it to conflict with anything that is
513 or contains pointer. */
514 if (set1 == voidptr_set || set2 == voidptr_set)
516 ++alias_stats.num_universal;
517 return true;
519 /* If one of sets is (non-universal) pointer and the other
520 contains universal pointer, we also get conflict. */
521 if (ase1->is_pointer && set2 != voidptr_set
522 && ase2->children && ase2->children->get (voidptr_set))
524 ++alias_stats.num_universal;
525 return true;
527 if (ase2->is_pointer && set1 != voidptr_set
528 && ase1->children && ase1->children->get (voidptr_set))
530 ++alias_stats.num_universal;
531 return true;
535 ++alias_stats.num_disambiguated;
537 /* The two alias sets are distinct and neither one is the
538 child of the other. Therefore, they cannot conflict. */
539 return 0;
542 /* Return 1 if the two specified alias sets will always conflict. */
545 alias_sets_must_conflict_p (alias_set_type set1, alias_set_type set2)
547 /* Disable TBAA oracle with !flag_strict_aliasing. */
548 if (!flag_strict_aliasing)
549 return 1;
550 if (set1 == 0 || set2 == 0)
552 ++alias_stats.num_alias_zero;
553 return 1;
555 if (set1 == set2)
557 ++alias_stats.num_same_alias_set;
558 return 1;
561 return 0;
564 /* Return 1 if any MEM object of type T1 will always conflict (using the
565 dependency routines in this file) with any MEM object of type T2.
566 This is used when allocating temporary storage. If T1 and/or T2 are
567 NULL_TREE, it means we know nothing about the storage. */
570 objects_must_conflict_p (tree t1, tree t2)
572 alias_set_type set1, set2;
574 /* If neither has a type specified, we don't know if they'll conflict
575 because we may be using them to store objects of various types, for
576 example the argument and local variables areas of inlined functions. */
577 if (t1 == 0 && t2 == 0)
578 return 0;
580 /* If they are the same type, they must conflict. */
581 if (t1 == t2)
583 ++alias_stats.num_same_objects;
584 return 1;
586 /* Likewise if both are volatile. */
587 if (t1 != 0 && TYPE_VOLATILE (t1) && t2 != 0 && TYPE_VOLATILE (t2))
589 ++alias_stats.num_volatile;
590 return 1;
593 set1 = t1 ? get_alias_set (t1) : 0;
594 set2 = t2 ? get_alias_set (t2) : 0;
596 /* We can't use alias_sets_conflict_p because we must make sure
597 that every subtype of t1 will conflict with every subtype of
598 t2 for which a pair of subobjects of these respective subtypes
599 overlaps on the stack. */
600 return alias_sets_must_conflict_p (set1, set2);
603 /* Return the outermost parent of component present in the chain of
604 component references handled by get_inner_reference in T with the
605 following property:
606 - the component is non-addressable, or
607 - the parent has alias set zero,
608 or NULL_TREE if no such parent exists. In the former cases, the alias
609 set of this parent is the alias set that must be used for T itself. */
611 tree
612 component_uses_parent_alias_set_from (const_tree t)
614 const_tree found = NULL_TREE;
616 if (AGGREGATE_TYPE_P (TREE_TYPE (t))
617 && TYPE_TYPELESS_STORAGE (TREE_TYPE (t)))
618 return const_cast <tree> (t);
620 while (handled_component_p (t))
622 switch (TREE_CODE (t))
624 case COMPONENT_REF:
625 if (DECL_NONADDRESSABLE_P (TREE_OPERAND (t, 1)))
626 found = t;
627 /* Permit type-punning when accessing a union, provided the access
628 is directly through the union. For example, this code does not
629 permit taking the address of a union member and then storing
630 through it. Even the type-punning allowed here is a GCC
631 extension, albeit a common and useful one; the C standard says
632 that such accesses have implementation-defined behavior. */
633 else if (TREE_CODE (TREE_TYPE (TREE_OPERAND (t, 0))) == UNION_TYPE)
634 found = t;
635 break;
637 case ARRAY_REF:
638 case ARRAY_RANGE_REF:
639 if (TYPE_NONALIASED_COMPONENT (TREE_TYPE (TREE_OPERAND (t, 0))))
640 found = t;
641 break;
643 case REALPART_EXPR:
644 case IMAGPART_EXPR:
645 break;
647 case BIT_FIELD_REF:
648 case VIEW_CONVERT_EXPR:
649 /* Bitfields and casts are never addressable. */
650 found = t;
651 break;
653 default:
654 gcc_unreachable ();
657 if (get_alias_set (TREE_TYPE (TREE_OPERAND (t, 0))) == 0)
658 found = t;
660 t = TREE_OPERAND (t, 0);
663 if (found)
664 return TREE_OPERAND (found, 0);
666 return NULL_TREE;
670 /* Return whether the pointer-type T effective for aliasing may
671 access everything and thus the reference has to be assigned
672 alias-set zero. */
674 static bool
675 ref_all_alias_ptr_type_p (const_tree t)
677 return (TREE_CODE (TREE_TYPE (t)) == VOID_TYPE
678 || TYPE_REF_CAN_ALIAS_ALL (t));
681 /* Return the alias set for the memory pointed to by T, which may be
682 either a type or an expression. Return -1 if there is nothing
683 special about dereferencing T. */
685 static alias_set_type
686 get_deref_alias_set_1 (tree t)
688 /* All we care about is the type. */
689 if (! TYPE_P (t))
690 t = TREE_TYPE (t);
692 /* If we have an INDIRECT_REF via a void pointer, we don't
693 know anything about what that might alias. Likewise if the
694 pointer is marked that way. */
695 if (ref_all_alias_ptr_type_p (t))
696 return 0;
698 return -1;
701 /* Return the alias set for the memory pointed to by T, which may be
702 either a type or an expression. */
704 alias_set_type
705 get_deref_alias_set (tree t)
707 /* If we're not doing any alias analysis, just assume everything
708 aliases everything else. */
709 if (!flag_strict_aliasing)
710 return 0;
712 alias_set_type set = get_deref_alias_set_1 (t);
714 /* Fall back to the alias-set of the pointed-to type. */
715 if (set == -1)
717 if (! TYPE_P (t))
718 t = TREE_TYPE (t);
719 set = get_alias_set (TREE_TYPE (t));
722 return set;
725 /* Return the pointer-type relevant for TBAA purposes from the
726 memory reference tree *T or NULL_TREE in which case *T is
727 adjusted to point to the outermost component reference that
728 can be used for assigning an alias set. */
730 static tree
731 reference_alias_ptr_type_1 (tree *t)
733 tree inner;
735 /* Get the base object of the reference. */
736 inner = *t;
737 while (handled_component_p (inner))
739 /* If there is a VIEW_CONVERT_EXPR in the chain we cannot use
740 the type of any component references that wrap it to
741 determine the alias-set. */
742 if (TREE_CODE (inner) == VIEW_CONVERT_EXPR)
743 *t = TREE_OPERAND (inner, 0);
744 inner = TREE_OPERAND (inner, 0);
747 /* Handle pointer dereferences here, they can override the
748 alias-set. */
749 if (INDIRECT_REF_P (inner)
750 && ref_all_alias_ptr_type_p (TREE_TYPE (TREE_OPERAND (inner, 0))))
751 return TREE_TYPE (TREE_OPERAND (inner, 0));
752 else if (TREE_CODE (inner) == TARGET_MEM_REF)
753 return TREE_TYPE (TMR_OFFSET (inner));
754 else if (TREE_CODE (inner) == MEM_REF
755 && ref_all_alias_ptr_type_p (TREE_TYPE (TREE_OPERAND (inner, 1))))
756 return TREE_TYPE (TREE_OPERAND (inner, 1));
758 /* If the innermost reference is a MEM_REF that has a
759 conversion embedded treat it like a VIEW_CONVERT_EXPR above,
760 using the memory access type for determining the alias-set. */
761 if (TREE_CODE (inner) == MEM_REF
762 && (TYPE_MAIN_VARIANT (TREE_TYPE (inner))
763 != TYPE_MAIN_VARIANT
764 (TREE_TYPE (TREE_TYPE (TREE_OPERAND (inner, 1))))))
765 return TREE_TYPE (TREE_OPERAND (inner, 1));
767 /* Otherwise, pick up the outermost object that we could have
768 a pointer to. */
769 tree tem = component_uses_parent_alias_set_from (*t);
770 if (tem)
771 *t = tem;
773 return NULL_TREE;
776 /* Return the pointer-type relevant for TBAA purposes from the
777 gimple memory reference tree T. This is the type to be used for
778 the offset operand of MEM_REF or TARGET_MEM_REF replacements of T
779 and guarantees that get_alias_set will return the same alias
780 set for T and the replacement. */
782 tree
783 reference_alias_ptr_type (tree t)
785 /* If the frontend assigns this alias-set zero, preserve that. */
786 if (lang_hooks.get_alias_set (t) == 0)
787 return ptr_type_node;
789 tree ptype = reference_alias_ptr_type_1 (&t);
790 /* If there is a given pointer type for aliasing purposes, return it. */
791 if (ptype != NULL_TREE)
792 return ptype;
794 /* Otherwise build one from the outermost component reference we
795 may use. */
796 if (TREE_CODE (t) == MEM_REF
797 || TREE_CODE (t) == TARGET_MEM_REF)
798 return TREE_TYPE (TREE_OPERAND (t, 1));
799 else
800 return build_pointer_type (TYPE_MAIN_VARIANT (TREE_TYPE (t)));
803 /* Return whether the pointer-types T1 and T2 used to determine
804 two alias sets of two references will yield the same answer
805 from get_deref_alias_set. */
807 bool
808 alias_ptr_types_compatible_p (tree t1, tree t2)
810 if (TYPE_MAIN_VARIANT (t1) == TYPE_MAIN_VARIANT (t2))
811 return true;
813 if (ref_all_alias_ptr_type_p (t1)
814 || ref_all_alias_ptr_type_p (t2))
815 return false;
817 return (TYPE_MAIN_VARIANT (TREE_TYPE (t1))
818 == TYPE_MAIN_VARIANT (TREE_TYPE (t2)));
821 /* Create emptry alias set entry. */
823 alias_set_entry *
824 init_alias_set_entry (alias_set_type set)
826 alias_set_entry *ase = ggc_alloc<alias_set_entry> ();
827 ase->alias_set = set;
828 ase->children = NULL;
829 ase->has_zero_child = false;
830 ase->is_pointer = false;
831 ase->has_pointer = false;
832 gcc_checking_assert (!get_alias_set_entry (set));
833 (*alias_sets)[set] = ase;
834 return ase;
837 /* Return the alias set for T, which may be either a type or an
838 expression. Call language-specific routine for help, if needed. */
840 alias_set_type
841 get_alias_set (tree t)
843 alias_set_type set;
845 /* We can not give up with -fno-strict-aliasing because we need to build
846 proper type representation for possible functions which are build with
847 -fstrict-aliasing. */
849 /* return 0 if this or its type is an error. */
850 if (t == error_mark_node
851 || (! TYPE_P (t)
852 && (TREE_TYPE (t) == 0 || TREE_TYPE (t) == error_mark_node)))
853 return 0;
855 /* We can be passed either an expression or a type. This and the
856 language-specific routine may make mutually-recursive calls to each other
857 to figure out what to do. At each juncture, we see if this is a tree
858 that the language may need to handle specially. First handle things that
859 aren't types. */
860 if (! TYPE_P (t))
862 /* Give the language a chance to do something with this tree
863 before we look at it. */
864 STRIP_NOPS (t);
865 set = lang_hooks.get_alias_set (t);
866 if (set != -1)
867 return set;
869 /* Get the alias pointer-type to use or the outermost object
870 that we could have a pointer to. */
871 tree ptype = reference_alias_ptr_type_1 (&t);
872 if (ptype != NULL)
873 return get_deref_alias_set (ptype);
875 /* If we've already determined the alias set for a decl, just return
876 it. This is necessary for C++ anonymous unions, whose component
877 variables don't look like union members (boo!). */
878 if (VAR_P (t)
879 && DECL_RTL_SET_P (t) && MEM_P (DECL_RTL (t)))
880 return MEM_ALIAS_SET (DECL_RTL (t));
882 /* Now all we care about is the type. */
883 t = TREE_TYPE (t);
886 /* Variant qualifiers don't affect the alias set, so get the main
887 variant. */
888 t = TYPE_MAIN_VARIANT (t);
890 if (AGGREGATE_TYPE_P (t)
891 && TYPE_TYPELESS_STORAGE (t))
892 return 0;
894 /* Always use the canonical type as well. If this is a type that
895 requires structural comparisons to identify compatible types
896 use alias set zero. */
897 if (TYPE_STRUCTURAL_EQUALITY_P (t))
899 /* Allow the language to specify another alias set for this
900 type. */
901 set = lang_hooks.get_alias_set (t);
902 if (set != -1)
903 return set;
904 /* Handle structure type equality for pointer types, arrays and vectors.
905 This is easy to do, because the code bellow ignore canonical types on
906 these anyway. This is important for LTO, where TYPE_CANONICAL for
907 pointers can not be meaningfuly computed by the frotnend. */
908 if (canonical_type_used_p (t))
910 /* In LTO we set canonical types for all types where it makes
911 sense to do so. Double check we did not miss some type. */
912 gcc_checking_assert (!in_lto_p || !type_with_alias_set_p (t));
913 return 0;
916 else
918 t = TYPE_CANONICAL (t);
919 gcc_checking_assert (!TYPE_STRUCTURAL_EQUALITY_P (t));
922 /* If this is a type with a known alias set, return it. */
923 gcc_checking_assert (t == TYPE_MAIN_VARIANT (t));
924 if (TYPE_ALIAS_SET_KNOWN_P (t))
925 return TYPE_ALIAS_SET (t);
927 /* We don't want to set TYPE_ALIAS_SET for incomplete types. */
928 if (!COMPLETE_TYPE_P (t))
930 /* For arrays with unknown size the conservative answer is the
931 alias set of the element type. */
932 if (TREE_CODE (t) == ARRAY_TYPE)
933 return get_alias_set (TREE_TYPE (t));
935 /* But return zero as a conservative answer for incomplete types. */
936 return 0;
939 /* See if the language has special handling for this type. */
940 set = lang_hooks.get_alias_set (t);
941 if (set != -1)
942 return set;
944 /* There are no objects of FUNCTION_TYPE, so there's no point in
945 using up an alias set for them. (There are, of course, pointers
946 and references to functions, but that's different.) */
947 else if (TREE_CODE (t) == FUNCTION_TYPE || TREE_CODE (t) == METHOD_TYPE)
948 set = 0;
950 /* Unless the language specifies otherwise, let vector types alias
951 their components. This avoids some nasty type punning issues in
952 normal usage. And indeed lets vectors be treated more like an
953 array slice. */
954 else if (TREE_CODE (t) == VECTOR_TYPE)
955 set = get_alias_set (TREE_TYPE (t));
957 /* Unless the language specifies otherwise, treat array types the
958 same as their components. This avoids the asymmetry we get
959 through recording the components. Consider accessing a
960 character(kind=1) through a reference to a character(kind=1)[1:1].
961 Or consider if we want to assign integer(kind=4)[0:D.1387] and
962 integer(kind=4)[4] the same alias set or not.
963 Just be pragmatic here and make sure the array and its element
964 type get the same alias set assigned. */
965 else if (TREE_CODE (t) == ARRAY_TYPE
966 && (!TYPE_NONALIASED_COMPONENT (t)
967 || TYPE_STRUCTURAL_EQUALITY_P (t)))
968 set = get_alias_set (TREE_TYPE (t));
970 /* From the former common C and C++ langhook implementation:
972 Unfortunately, there is no canonical form of a pointer type.
973 In particular, if we have `typedef int I', then `int *', and
974 `I *' are different types. So, we have to pick a canonical
975 representative. We do this below.
977 Technically, this approach is actually more conservative that
978 it needs to be. In particular, `const int *' and `int *'
979 should be in different alias sets, according to the C and C++
980 standard, since their types are not the same, and so,
981 technically, an `int **' and `const int **' cannot point at
982 the same thing.
984 But, the standard is wrong. In particular, this code is
985 legal C++:
987 int *ip;
988 int **ipp = &ip;
989 const int* const* cipp = ipp;
990 And, it doesn't make sense for that to be legal unless you
991 can dereference IPP and CIPP. So, we ignore cv-qualifiers on
992 the pointed-to types. This issue has been reported to the
993 C++ committee.
995 For this reason go to canonical type of the unqalified pointer type.
996 Until GCC 6 this code set all pointers sets to have alias set of
997 ptr_type_node but that is a bad idea, because it prevents disabiguations
998 in between pointers. For Firefox this accounts about 20% of all
999 disambiguations in the program. */
1000 else if (POINTER_TYPE_P (t) && t != ptr_type_node)
1002 tree p;
1003 auto_vec <bool, 8> reference;
1005 /* Unnest all pointers and references.
1006 We also want to make pointer to array/vector equivalent to pointer to
1007 its element (see the reasoning above). Skip all those types, too. */
1008 for (p = t; POINTER_TYPE_P (p)
1009 || (TREE_CODE (p) == ARRAY_TYPE
1010 && (!TYPE_NONALIASED_COMPONENT (p)
1011 || !COMPLETE_TYPE_P (p)
1012 || TYPE_STRUCTURAL_EQUALITY_P (p)))
1013 || TREE_CODE (p) == VECTOR_TYPE;
1014 p = TREE_TYPE (p))
1016 /* Ada supports recusive pointers. Instead of doing recrusion check
1017 just give up once the preallocated space of 8 elements is up.
1018 In this case just punt to void * alias set. */
1019 if (reference.length () == 8)
1021 p = ptr_type_node;
1022 break;
1024 if (TREE_CODE (p) == REFERENCE_TYPE)
1025 /* In LTO we want languages that use references to be compatible
1026 with languages that use pointers. */
1027 reference.safe_push (true && !in_lto_p);
1028 if (TREE_CODE (p) == POINTER_TYPE)
1029 reference.safe_push (false);
1031 p = TYPE_MAIN_VARIANT (p);
1033 /* Make void * compatible with char * and also void **.
1034 Programs are commonly violating TBAA by this.
1036 We also make void * to conflict with every pointer
1037 (see record_component_aliases) and thus it is safe it to use it for
1038 pointers to types with TYPE_STRUCTURAL_EQUALITY_P. */
1039 if (TREE_CODE (p) == VOID_TYPE || TYPE_STRUCTURAL_EQUALITY_P (p))
1040 set = get_alias_set (ptr_type_node);
1041 else
1043 /* Rebuild pointer type starting from canonical types using
1044 unqualified pointers and references only. This way all such
1045 pointers will have the same alias set and will conflict with
1046 each other.
1048 Most of time we already have pointers or references of a given type.
1049 If not we build new one just to be sure that if someone later
1050 (probably only middle-end can, as we should assign all alias
1051 classes only after finishing translation unit) builds the pointer
1052 type, the canonical type will match. */
1053 p = TYPE_CANONICAL (p);
1054 while (!reference.is_empty ())
1056 if (reference.pop ())
1057 p = build_reference_type (p);
1058 else
1059 p = build_pointer_type (p);
1060 gcc_checking_assert (p == TYPE_MAIN_VARIANT (p));
1061 /* build_pointer_type should always return the canonical type.
1062 For LTO TYPE_CANOINCAL may be NULL, because we do not compute
1063 them. Be sure that frontends do not glob canonical types of
1064 pointers in unexpected way and that p == TYPE_CANONICAL (p)
1065 in all other cases. */
1066 gcc_checking_assert (!TYPE_CANONICAL (p)
1067 || p == TYPE_CANONICAL (p));
1070 /* Assign the alias set to both p and t.
1071 We can not call get_alias_set (p) here as that would trigger
1072 infinite recursion when p == t. In other cases it would just
1073 trigger unnecesary legwork of rebuilding the pointer again. */
1074 gcc_checking_assert (p == TYPE_MAIN_VARIANT (p));
1075 if (TYPE_ALIAS_SET_KNOWN_P (p))
1076 set = TYPE_ALIAS_SET (p);
1077 else
1079 set = new_alias_set ();
1080 TYPE_ALIAS_SET (p) = set;
1084 /* Alias set of ptr_type_node is special and serve as universal pointer which
1085 is TBAA compatible with every other pointer type. Be sure we have the
1086 alias set built even for LTO which otherwise keeps all TYPE_CANONICAL
1087 of pointer types NULL. */
1088 else if (t == ptr_type_node)
1089 set = new_alias_set ();
1091 /* Otherwise make a new alias set for this type. */
1092 else
1094 /* Each canonical type gets its own alias set, so canonical types
1095 shouldn't form a tree. It doesn't really matter for types
1096 we handle specially above, so only check it where it possibly
1097 would result in a bogus alias set. */
1098 gcc_checking_assert (TYPE_CANONICAL (t) == t);
1100 set = new_alias_set ();
1103 TYPE_ALIAS_SET (t) = set;
1105 /* If this is an aggregate type or a complex type, we must record any
1106 component aliasing information. */
1107 if (AGGREGATE_TYPE_P (t) || TREE_CODE (t) == COMPLEX_TYPE)
1108 record_component_aliases (t);
1110 /* We treat pointer types specially in alias_set_subset_of. */
1111 if (POINTER_TYPE_P (t) && set)
1113 alias_set_entry *ase = get_alias_set_entry (set);
1114 if (!ase)
1115 ase = init_alias_set_entry (set);
1116 ase->is_pointer = true;
1117 ase->has_pointer = true;
1120 return set;
1123 /* Return a brand-new alias set. */
1125 alias_set_type
1126 new_alias_set (void)
1128 if (alias_sets == 0)
1129 vec_safe_push (alias_sets, (alias_set_entry *) NULL);
1130 vec_safe_push (alias_sets, (alias_set_entry *) NULL);
1131 return alias_sets->length () - 1;
1134 /* Indicate that things in SUBSET can alias things in SUPERSET, but that
1135 not everything that aliases SUPERSET also aliases SUBSET. For example,
1136 in C, a store to an `int' can alias a load of a structure containing an
1137 `int', and vice versa. But it can't alias a load of a 'double' member
1138 of the same structure. Here, the structure would be the SUPERSET and
1139 `int' the SUBSET. This relationship is also described in the comment at
1140 the beginning of this file.
1142 This function should be called only once per SUPERSET/SUBSET pair.
1144 It is illegal for SUPERSET to be zero; everything is implicitly a
1145 subset of alias set zero. */
1147 void
1148 record_alias_subset (alias_set_type superset, alias_set_type subset)
1150 alias_set_entry *superset_entry;
1151 alias_set_entry *subset_entry;
1153 /* It is possible in complex type situations for both sets to be the same,
1154 in which case we can ignore this operation. */
1155 if (superset == subset)
1156 return;
1158 gcc_assert (superset);
1160 superset_entry = get_alias_set_entry (superset);
1161 if (superset_entry == 0)
1163 /* Create an entry for the SUPERSET, so that we have a place to
1164 attach the SUBSET. */
1165 superset_entry = init_alias_set_entry (superset);
1168 if (subset == 0)
1169 superset_entry->has_zero_child = 1;
1170 else
1172 subset_entry = get_alias_set_entry (subset);
1173 if (!superset_entry->children)
1174 superset_entry->children
1175 = hash_map<alias_set_hash, int>::create_ggc (64);
1176 /* If there is an entry for the subset, enter all of its children
1177 (if they are not already present) as children of the SUPERSET. */
1178 if (subset_entry)
1180 if (subset_entry->has_zero_child)
1181 superset_entry->has_zero_child = true;
1182 if (subset_entry->has_pointer)
1183 superset_entry->has_pointer = true;
1185 if (subset_entry->children)
1187 hash_map<alias_set_hash, int>::iterator iter
1188 = subset_entry->children->begin ();
1189 for (; iter != subset_entry->children->end (); ++iter)
1190 superset_entry->children->put ((*iter).first, (*iter).second);
1194 /* Enter the SUBSET itself as a child of the SUPERSET. */
1195 superset_entry->children->put (subset, 0);
1199 /* Record that component types of TYPE, if any, are part of that type for
1200 aliasing purposes. For record types, we only record component types
1201 for fields that are not marked non-addressable. For array types, we
1202 only record the component type if it is not marked non-aliased. */
1204 void
1205 record_component_aliases (tree type)
1207 alias_set_type superset = get_alias_set (type);
1208 tree field;
1210 if (superset == 0)
1211 return;
1213 switch (TREE_CODE (type))
1215 case RECORD_TYPE:
1216 case UNION_TYPE:
1217 case QUAL_UNION_TYPE:
1218 for (field = TYPE_FIELDS (type); field != 0; field = DECL_CHAIN (field))
1219 if (TREE_CODE (field) == FIELD_DECL && !DECL_NONADDRESSABLE_P (field))
1221 /* LTO type merging does not make any difference between
1222 component pointer types. We may have
1224 struct foo {int *a;};
1226 as TYPE_CANONICAL of
1228 struct bar {float *a;};
1230 Because accesses to int * and float * do not alias, we would get
1231 false negative when accessing the same memory location by
1232 float ** and bar *. We thus record the canonical type as:
1234 struct {void *a;};
1236 void * is special cased and works as a universal pointer type.
1237 Accesses to it conflicts with accesses to any other pointer
1238 type. */
1239 tree t = TREE_TYPE (field);
1240 if (in_lto_p)
1242 /* VECTOR_TYPE and ARRAY_TYPE share the alias set with their
1243 element type and that type has to be normalized to void *,
1244 too, in the case it is a pointer. */
1245 while (!canonical_type_used_p (t) && !POINTER_TYPE_P (t))
1247 gcc_checking_assert (TYPE_STRUCTURAL_EQUALITY_P (t));
1248 t = TREE_TYPE (t);
1250 if (POINTER_TYPE_P (t))
1251 t = ptr_type_node;
1252 else if (flag_checking)
1253 gcc_checking_assert (get_alias_set (t)
1254 == get_alias_set (TREE_TYPE (field)));
1257 record_alias_subset (superset, get_alias_set (t));
1259 break;
1261 case COMPLEX_TYPE:
1262 record_alias_subset (superset, get_alias_set (TREE_TYPE (type)));
1263 break;
1265 /* VECTOR_TYPE and ARRAY_TYPE share the alias set with their
1266 element type. */
1268 default:
1269 break;
1273 /* Allocate an alias set for use in storing and reading from the varargs
1274 spill area. */
1276 static GTY(()) alias_set_type varargs_set = -1;
1278 alias_set_type
1279 get_varargs_alias_set (void)
1281 #if 1
1282 /* We now lower VA_ARG_EXPR, and there's currently no way to attach the
1283 varargs alias set to an INDIRECT_REF (FIXME!), so we can't
1284 consistently use the varargs alias set for loads from the varargs
1285 area. So don't use it anywhere. */
1286 return 0;
1287 #else
1288 if (varargs_set == -1)
1289 varargs_set = new_alias_set ();
1291 return varargs_set;
1292 #endif
1295 /* Likewise, but used for the fixed portions of the frame, e.g., register
1296 save areas. */
1298 static GTY(()) alias_set_type frame_set = -1;
1300 alias_set_type
1301 get_frame_alias_set (void)
1303 if (frame_set == -1)
1304 frame_set = new_alias_set ();
1306 return frame_set;
1309 /* Create a new, unique base with id ID. */
1311 static rtx
1312 unique_base_value (HOST_WIDE_INT id)
1314 return gen_rtx_ADDRESS (Pmode, id);
1317 /* Return true if accesses based on any other base value cannot alias
1318 those based on X. */
1320 static bool
1321 unique_base_value_p (rtx x)
1323 return GET_CODE (x) == ADDRESS && GET_MODE (x) == Pmode;
1326 /* Return true if X is known to be a base value. */
1328 static bool
1329 known_base_value_p (rtx x)
1331 switch (GET_CODE (x))
1333 case LABEL_REF:
1334 case SYMBOL_REF:
1335 return true;
1337 case ADDRESS:
1338 /* Arguments may or may not be bases; we don't know for sure. */
1339 return GET_MODE (x) != VOIDmode;
1341 default:
1342 return false;
1346 /* Inside SRC, the source of a SET, find a base address. */
1348 static rtx
1349 find_base_value (rtx src)
1351 unsigned int regno;
1353 #if defined (FIND_BASE_TERM)
1354 /* Try machine-dependent ways to find the base term. */
1355 src = FIND_BASE_TERM (src);
1356 #endif
1358 switch (GET_CODE (src))
1360 case SYMBOL_REF:
1361 case LABEL_REF:
1362 return src;
1364 case REG:
1365 regno = REGNO (src);
1366 /* At the start of a function, argument registers have known base
1367 values which may be lost later. Returning an ADDRESS
1368 expression here allows optimization based on argument values
1369 even when the argument registers are used for other purposes. */
1370 if (regno < FIRST_PSEUDO_REGISTER && copying_arguments)
1371 return new_reg_base_value[regno];
1373 /* If a pseudo has a known base value, return it. Do not do this
1374 for non-fixed hard regs since it can result in a circular
1375 dependency chain for registers which have values at function entry.
1377 The test above is not sufficient because the scheduler may move
1378 a copy out of an arg reg past the NOTE_INSN_FUNCTION_BEGIN. */
1379 if ((regno >= FIRST_PSEUDO_REGISTER || fixed_regs[regno])
1380 && regno < vec_safe_length (reg_base_value))
1382 /* If we're inside init_alias_analysis, use new_reg_base_value
1383 to reduce the number of relaxation iterations. */
1384 if (new_reg_base_value && new_reg_base_value[regno]
1385 && DF_REG_DEF_COUNT (regno) == 1)
1386 return new_reg_base_value[regno];
1388 if ((*reg_base_value)[regno])
1389 return (*reg_base_value)[regno];
1392 return 0;
1394 case MEM:
1395 /* Check for an argument passed in memory. Only record in the
1396 copying-arguments block; it is too hard to track changes
1397 otherwise. */
1398 if (copying_arguments
1399 && (XEXP (src, 0) == arg_pointer_rtx
1400 || (GET_CODE (XEXP (src, 0)) == PLUS
1401 && XEXP (XEXP (src, 0), 0) == arg_pointer_rtx)))
1402 return arg_base_value;
1403 return 0;
1405 case CONST:
1406 src = XEXP (src, 0);
1407 if (GET_CODE (src) != PLUS && GET_CODE (src) != MINUS)
1408 break;
1410 /* fall through */
1412 case PLUS:
1413 case MINUS:
1415 rtx temp, src_0 = XEXP (src, 0), src_1 = XEXP (src, 1);
1417 /* If either operand is a REG that is a known pointer, then it
1418 is the base. */
1419 if (REG_P (src_0) && REG_POINTER (src_0))
1420 return find_base_value (src_0);
1421 if (REG_P (src_1) && REG_POINTER (src_1))
1422 return find_base_value (src_1);
1424 /* If either operand is a REG, then see if we already have
1425 a known value for it. */
1426 if (REG_P (src_0))
1428 temp = find_base_value (src_0);
1429 if (temp != 0)
1430 src_0 = temp;
1433 if (REG_P (src_1))
1435 temp = find_base_value (src_1);
1436 if (temp!= 0)
1437 src_1 = temp;
1440 /* If either base is named object or a special address
1441 (like an argument or stack reference), then use it for the
1442 base term. */
1443 if (src_0 != 0 && known_base_value_p (src_0))
1444 return src_0;
1446 if (src_1 != 0 && known_base_value_p (src_1))
1447 return src_1;
1449 /* Guess which operand is the base address:
1450 If either operand is a symbol, then it is the base. If
1451 either operand is a CONST_INT, then the other is the base. */
1452 if (CONST_INT_P (src_1) || CONSTANT_P (src_0))
1453 return find_base_value (src_0);
1454 else if (CONST_INT_P (src_0) || CONSTANT_P (src_1))
1455 return find_base_value (src_1);
1457 return 0;
1460 case LO_SUM:
1461 /* The standard form is (lo_sum reg sym) so look only at the
1462 second operand. */
1463 return find_base_value (XEXP (src, 1));
1465 case AND:
1466 /* If the second operand is constant set the base
1467 address to the first operand. */
1468 if (CONST_INT_P (XEXP (src, 1)) && INTVAL (XEXP (src, 1)) != 0)
1469 return find_base_value (XEXP (src, 0));
1470 return 0;
1472 case TRUNCATE:
1473 /* As we do not know which address space the pointer is referring to, we can
1474 handle this only if the target does not support different pointer or
1475 address modes depending on the address space. */
1476 if (!target_default_pointer_address_modes_p ())
1477 break;
1478 if (GET_MODE_SIZE (GET_MODE (src)) < GET_MODE_SIZE (Pmode))
1479 break;
1480 /* Fall through. */
1481 case HIGH:
1482 case PRE_INC:
1483 case PRE_DEC:
1484 case POST_INC:
1485 case POST_DEC:
1486 case PRE_MODIFY:
1487 case POST_MODIFY:
1488 return find_base_value (XEXP (src, 0));
1490 case ZERO_EXTEND:
1491 case SIGN_EXTEND: /* used for NT/Alpha pointers */
1492 /* As we do not know which address space the pointer is referring to, we can
1493 handle this only if the target does not support different pointer or
1494 address modes depending on the address space. */
1495 if (!target_default_pointer_address_modes_p ())
1496 break;
1499 rtx temp = find_base_value (XEXP (src, 0));
1501 if (temp != 0 && CONSTANT_P (temp))
1502 temp = convert_memory_address (Pmode, temp);
1504 return temp;
1507 default:
1508 break;
1511 return 0;
1514 /* Called from init_alias_analysis indirectly through note_stores,
1515 or directly if DEST is a register with a REG_NOALIAS note attached.
1516 SET is null in the latter case. */
1518 /* While scanning insns to find base values, reg_seen[N] is nonzero if
1519 register N has been set in this function. */
1520 static sbitmap reg_seen;
1522 static void
1523 record_set (rtx dest, const_rtx set, void *data ATTRIBUTE_UNUSED)
1525 unsigned regno;
1526 rtx src;
1527 int n;
1529 if (!REG_P (dest))
1530 return;
1532 regno = REGNO (dest);
1534 gcc_checking_assert (regno < reg_base_value->length ());
1536 n = REG_NREGS (dest);
1537 if (n != 1)
1539 while (--n >= 0)
1541 bitmap_set_bit (reg_seen, regno + n);
1542 new_reg_base_value[regno + n] = 0;
1544 return;
1547 if (set)
1549 /* A CLOBBER wipes out any old value but does not prevent a previously
1550 unset register from acquiring a base address (i.e. reg_seen is not
1551 set). */
1552 if (GET_CODE (set) == CLOBBER)
1554 new_reg_base_value[regno] = 0;
1555 return;
1557 src = SET_SRC (set);
1559 else
1561 /* There's a REG_NOALIAS note against DEST. */
1562 if (bitmap_bit_p (reg_seen, regno))
1564 new_reg_base_value[regno] = 0;
1565 return;
1567 bitmap_set_bit (reg_seen, regno);
1568 new_reg_base_value[regno] = unique_base_value (unique_id++);
1569 return;
1572 /* If this is not the first set of REGNO, see whether the new value
1573 is related to the old one. There are two cases of interest:
1575 (1) The register might be assigned an entirely new value
1576 that has the same base term as the original set.
1578 (2) The set might be a simple self-modification that
1579 cannot change REGNO's base value.
1581 If neither case holds, reject the original base value as invalid.
1582 Note that the following situation is not detected:
1584 extern int x, y; int *p = &x; p += (&y-&x);
1586 ANSI C does not allow computing the difference of addresses
1587 of distinct top level objects. */
1588 if (new_reg_base_value[regno] != 0
1589 && find_base_value (src) != new_reg_base_value[regno])
1590 switch (GET_CODE (src))
1592 case LO_SUM:
1593 case MINUS:
1594 if (XEXP (src, 0) != dest && XEXP (src, 1) != dest)
1595 new_reg_base_value[regno] = 0;
1596 break;
1597 case PLUS:
1598 /* If the value we add in the PLUS is also a valid base value,
1599 this might be the actual base value, and the original value
1600 an index. */
1602 rtx other = NULL_RTX;
1604 if (XEXP (src, 0) == dest)
1605 other = XEXP (src, 1);
1606 else if (XEXP (src, 1) == dest)
1607 other = XEXP (src, 0);
1609 if (! other || find_base_value (other))
1610 new_reg_base_value[regno] = 0;
1611 break;
1613 case AND:
1614 if (XEXP (src, 0) != dest || !CONST_INT_P (XEXP (src, 1)))
1615 new_reg_base_value[regno] = 0;
1616 break;
1617 default:
1618 new_reg_base_value[regno] = 0;
1619 break;
1621 /* If this is the first set of a register, record the value. */
1622 else if ((regno >= FIRST_PSEUDO_REGISTER || ! fixed_regs[regno])
1623 && ! bitmap_bit_p (reg_seen, regno) && new_reg_base_value[regno] == 0)
1624 new_reg_base_value[regno] = find_base_value (src);
1626 bitmap_set_bit (reg_seen, regno);
1629 /* Return REG_BASE_VALUE for REGNO. Selective scheduler uses this to avoid
1630 using hard registers with non-null REG_BASE_VALUE for renaming. */
1632 get_reg_base_value (unsigned int regno)
1634 return (*reg_base_value)[regno];
1637 /* If a value is known for REGNO, return it. */
1640 get_reg_known_value (unsigned int regno)
1642 if (regno >= FIRST_PSEUDO_REGISTER)
1644 regno -= FIRST_PSEUDO_REGISTER;
1645 if (regno < vec_safe_length (reg_known_value))
1646 return (*reg_known_value)[regno];
1648 return NULL;
1651 /* Set it. */
1653 static void
1654 set_reg_known_value (unsigned int regno, rtx val)
1656 if (regno >= FIRST_PSEUDO_REGISTER)
1658 regno -= FIRST_PSEUDO_REGISTER;
1659 if (regno < vec_safe_length (reg_known_value))
1660 (*reg_known_value)[regno] = val;
1664 /* Similarly for reg_known_equiv_p. */
1666 bool
1667 get_reg_known_equiv_p (unsigned int regno)
1669 if (regno >= FIRST_PSEUDO_REGISTER)
1671 regno -= FIRST_PSEUDO_REGISTER;
1672 if (regno < vec_safe_length (reg_known_value))
1673 return bitmap_bit_p (reg_known_equiv_p, regno);
1675 return false;
1678 static void
1679 set_reg_known_equiv_p (unsigned int regno, bool val)
1681 if (regno >= FIRST_PSEUDO_REGISTER)
1683 regno -= FIRST_PSEUDO_REGISTER;
1684 if (regno < vec_safe_length (reg_known_value))
1686 if (val)
1687 bitmap_set_bit (reg_known_equiv_p, regno);
1688 else
1689 bitmap_clear_bit (reg_known_equiv_p, regno);
1695 /* Returns a canonical version of X, from the point of view alias
1696 analysis. (For example, if X is a MEM whose address is a register,
1697 and the register has a known value (say a SYMBOL_REF), then a MEM
1698 whose address is the SYMBOL_REF is returned.) */
1701 canon_rtx (rtx x)
1703 /* Recursively look for equivalences. */
1704 if (REG_P (x) && REGNO (x) >= FIRST_PSEUDO_REGISTER)
1706 rtx t = get_reg_known_value (REGNO (x));
1707 if (t == x)
1708 return x;
1709 if (t)
1710 return canon_rtx (t);
1713 if (GET_CODE (x) == PLUS)
1715 rtx x0 = canon_rtx (XEXP (x, 0));
1716 rtx x1 = canon_rtx (XEXP (x, 1));
1718 if (x0 != XEXP (x, 0) || x1 != XEXP (x, 1))
1719 return simplify_gen_binary (PLUS, GET_MODE (x), x0, x1);
1722 /* This gives us much better alias analysis when called from
1723 the loop optimizer. Note we want to leave the original
1724 MEM alone, but need to return the canonicalized MEM with
1725 all the flags with their original values. */
1726 else if (MEM_P (x))
1727 x = replace_equiv_address_nv (x, canon_rtx (XEXP (x, 0)));
1729 return x;
1732 /* Return 1 if X and Y are identical-looking rtx's.
1733 Expect that X and Y has been already canonicalized.
1735 We use the data in reg_known_value above to see if two registers with
1736 different numbers are, in fact, equivalent. */
1738 static int
1739 rtx_equal_for_memref_p (const_rtx x, const_rtx y)
1741 int i;
1742 int j;
1743 enum rtx_code code;
1744 const char *fmt;
1746 if (x == 0 && y == 0)
1747 return 1;
1748 if (x == 0 || y == 0)
1749 return 0;
1751 if (x == y)
1752 return 1;
1754 code = GET_CODE (x);
1755 /* Rtx's of different codes cannot be equal. */
1756 if (code != GET_CODE (y))
1757 return 0;
1759 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent.
1760 (REG:SI x) and (REG:HI x) are NOT equivalent. */
1762 if (GET_MODE (x) != GET_MODE (y))
1763 return 0;
1765 /* Some RTL can be compared without a recursive examination. */
1766 switch (code)
1768 case REG:
1769 return REGNO (x) == REGNO (y);
1771 case LABEL_REF:
1772 return label_ref_label (x) == label_ref_label (y);
1774 case SYMBOL_REF:
1775 return compare_base_symbol_refs (x, y) == 1;
1777 case ENTRY_VALUE:
1778 /* This is magic, don't go through canonicalization et al. */
1779 return rtx_equal_p (ENTRY_VALUE_EXP (x), ENTRY_VALUE_EXP (y));
1781 case VALUE:
1782 CASE_CONST_UNIQUE:
1783 /* Pointer equality guarantees equality for these nodes. */
1784 return 0;
1786 default:
1787 break;
1790 /* canon_rtx knows how to handle plus. No need to canonicalize. */
1791 if (code == PLUS)
1792 return ((rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 0))
1793 && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 1)))
1794 || (rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 1))
1795 && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 0))));
1796 /* For commutative operations, the RTX match if the operand match in any
1797 order. Also handle the simple binary and unary cases without a loop. */
1798 if (COMMUTATIVE_P (x))
1800 rtx xop0 = canon_rtx (XEXP (x, 0));
1801 rtx yop0 = canon_rtx (XEXP (y, 0));
1802 rtx yop1 = canon_rtx (XEXP (y, 1));
1804 return ((rtx_equal_for_memref_p (xop0, yop0)
1805 && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), yop1))
1806 || (rtx_equal_for_memref_p (xop0, yop1)
1807 && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), yop0)));
1809 else if (NON_COMMUTATIVE_P (x))
1811 return (rtx_equal_for_memref_p (canon_rtx (XEXP (x, 0)),
1812 canon_rtx (XEXP (y, 0)))
1813 && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)),
1814 canon_rtx (XEXP (y, 1))));
1816 else if (UNARY_P (x))
1817 return rtx_equal_for_memref_p (canon_rtx (XEXP (x, 0)),
1818 canon_rtx (XEXP (y, 0)));
1820 /* Compare the elements. If any pair of corresponding elements
1821 fail to match, return 0 for the whole things.
1823 Limit cases to types which actually appear in addresses. */
1825 fmt = GET_RTX_FORMAT (code);
1826 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
1828 switch (fmt[i])
1830 case 'i':
1831 if (XINT (x, i) != XINT (y, i))
1832 return 0;
1833 break;
1835 case 'E':
1836 /* Two vectors must have the same length. */
1837 if (XVECLEN (x, i) != XVECLEN (y, i))
1838 return 0;
1840 /* And the corresponding elements must match. */
1841 for (j = 0; j < XVECLEN (x, i); j++)
1842 if (rtx_equal_for_memref_p (canon_rtx (XVECEXP (x, i, j)),
1843 canon_rtx (XVECEXP (y, i, j))) == 0)
1844 return 0;
1845 break;
1847 case 'e':
1848 if (rtx_equal_for_memref_p (canon_rtx (XEXP (x, i)),
1849 canon_rtx (XEXP (y, i))) == 0)
1850 return 0;
1851 break;
1853 /* This can happen for asm operands. */
1854 case 's':
1855 if (strcmp (XSTR (x, i), XSTR (y, i)))
1856 return 0;
1857 break;
1859 /* This can happen for an asm which clobbers memory. */
1860 case '0':
1861 break;
1863 /* It is believed that rtx's at this level will never
1864 contain anything but integers and other rtx's,
1865 except for within LABEL_REFs and SYMBOL_REFs. */
1866 default:
1867 gcc_unreachable ();
1870 return 1;
1873 static rtx
1874 find_base_term (rtx x)
1876 cselib_val *val;
1877 struct elt_loc_list *l, *f;
1878 rtx ret;
1880 #if defined (FIND_BASE_TERM)
1881 /* Try machine-dependent ways to find the base term. */
1882 x = FIND_BASE_TERM (x);
1883 #endif
1885 switch (GET_CODE (x))
1887 case REG:
1888 return REG_BASE_VALUE (x);
1890 case TRUNCATE:
1891 /* As we do not know which address space the pointer is referring to, we can
1892 handle this only if the target does not support different pointer or
1893 address modes depending on the address space. */
1894 if (!target_default_pointer_address_modes_p ())
1895 return 0;
1896 if (GET_MODE_SIZE (GET_MODE (x)) < GET_MODE_SIZE (Pmode))
1897 return 0;
1898 /* Fall through. */
1899 case HIGH:
1900 case PRE_INC:
1901 case PRE_DEC:
1902 case POST_INC:
1903 case POST_DEC:
1904 case PRE_MODIFY:
1905 case POST_MODIFY:
1906 return find_base_term (XEXP (x, 0));
1908 case ZERO_EXTEND:
1909 case SIGN_EXTEND: /* Used for Alpha/NT pointers */
1910 /* As we do not know which address space the pointer is referring to, we can
1911 handle this only if the target does not support different pointer or
1912 address modes depending on the address space. */
1913 if (!target_default_pointer_address_modes_p ())
1914 return 0;
1917 rtx temp = find_base_term (XEXP (x, 0));
1919 if (temp != 0 && CONSTANT_P (temp))
1920 temp = convert_memory_address (Pmode, temp);
1922 return temp;
1925 case VALUE:
1926 val = CSELIB_VAL_PTR (x);
1927 ret = NULL_RTX;
1929 if (!val)
1930 return ret;
1932 if (cselib_sp_based_value_p (val))
1933 return static_reg_base_value[STACK_POINTER_REGNUM];
1935 f = val->locs;
1936 /* Temporarily reset val->locs to avoid infinite recursion. */
1937 val->locs = NULL;
1939 for (l = f; l; l = l->next)
1940 if (GET_CODE (l->loc) == VALUE
1941 && CSELIB_VAL_PTR (l->loc)->locs
1942 && !CSELIB_VAL_PTR (l->loc)->locs->next
1943 && CSELIB_VAL_PTR (l->loc)->locs->loc == x)
1944 continue;
1945 else if ((ret = find_base_term (l->loc)) != 0)
1946 break;
1948 val->locs = f;
1949 return ret;
1951 case LO_SUM:
1952 /* The standard form is (lo_sum reg sym) so look only at the
1953 second operand. */
1954 return find_base_term (XEXP (x, 1));
1956 case CONST:
1957 x = XEXP (x, 0);
1958 if (GET_CODE (x) != PLUS && GET_CODE (x) != MINUS)
1959 return 0;
1960 /* Fall through. */
1961 case PLUS:
1962 case MINUS:
1964 rtx tmp1 = XEXP (x, 0);
1965 rtx tmp2 = XEXP (x, 1);
1967 /* This is a little bit tricky since we have to determine which of
1968 the two operands represents the real base address. Otherwise this
1969 routine may return the index register instead of the base register.
1971 That may cause us to believe no aliasing was possible, when in
1972 fact aliasing is possible.
1974 We use a few simple tests to guess the base register. Additional
1975 tests can certainly be added. For example, if one of the operands
1976 is a shift or multiply, then it must be the index register and the
1977 other operand is the base register. */
1979 if (tmp1 == pic_offset_table_rtx && CONSTANT_P (tmp2))
1980 return find_base_term (tmp2);
1982 /* If either operand is known to be a pointer, then prefer it
1983 to determine the base term. */
1984 if (REG_P (tmp1) && REG_POINTER (tmp1))
1986 else if (REG_P (tmp2) && REG_POINTER (tmp2))
1987 std::swap (tmp1, tmp2);
1988 /* If second argument is constant which has base term, prefer it
1989 over variable tmp1. See PR64025. */
1990 else if (CONSTANT_P (tmp2) && !CONST_INT_P (tmp2))
1991 std::swap (tmp1, tmp2);
1993 /* Go ahead and find the base term for both operands. If either base
1994 term is from a pointer or is a named object or a special address
1995 (like an argument or stack reference), then use it for the
1996 base term. */
1997 rtx base = find_base_term (tmp1);
1998 if (base != NULL_RTX
1999 && ((REG_P (tmp1) && REG_POINTER (tmp1))
2000 || known_base_value_p (base)))
2001 return base;
2002 base = find_base_term (tmp2);
2003 if (base != NULL_RTX
2004 && ((REG_P (tmp2) && REG_POINTER (tmp2))
2005 || known_base_value_p (base)))
2006 return base;
2008 /* We could not determine which of the two operands was the
2009 base register and which was the index. So we can determine
2010 nothing from the base alias check. */
2011 return 0;
2014 case AND:
2015 if (CONST_INT_P (XEXP (x, 1)) && INTVAL (XEXP (x, 1)) != 0)
2016 return find_base_term (XEXP (x, 0));
2017 return 0;
2019 case SYMBOL_REF:
2020 case LABEL_REF:
2021 return x;
2023 default:
2024 return 0;
2028 /* Return true if accesses to address X may alias accesses based
2029 on the stack pointer. */
2031 bool
2032 may_be_sp_based_p (rtx x)
2034 rtx base = find_base_term (x);
2035 return !base || base == static_reg_base_value[STACK_POINTER_REGNUM];
2038 /* BASE1 and BASE2 are decls. Return 1 if they refer to same object, 0
2039 if they refer to different objects and -1 if we can not decide. */
2042 compare_base_decls (tree base1, tree base2)
2044 int ret;
2045 gcc_checking_assert (DECL_P (base1) && DECL_P (base2));
2046 if (base1 == base2)
2047 return 1;
2049 /* If we have two register decls with register specification we
2050 cannot decide unless their assembler names are the same. */
2051 if (DECL_REGISTER (base1)
2052 && DECL_REGISTER (base2)
2053 && HAS_DECL_ASSEMBLER_NAME_P (base1)
2054 && HAS_DECL_ASSEMBLER_NAME_P (base2)
2055 && DECL_ASSEMBLER_NAME_SET_P (base1)
2056 && DECL_ASSEMBLER_NAME_SET_P (base2))
2058 if (DECL_ASSEMBLER_NAME_RAW (base1) == DECL_ASSEMBLER_NAME_RAW (base2))
2059 return 1;
2060 return -1;
2063 /* Declarations of non-automatic variables may have aliases. All other
2064 decls are unique. */
2065 if (!decl_in_symtab_p (base1)
2066 || !decl_in_symtab_p (base2))
2067 return 0;
2069 /* Don't cause symbols to be inserted by the act of checking. */
2070 symtab_node *node1 = symtab_node::get (base1);
2071 if (!node1)
2072 return 0;
2073 symtab_node *node2 = symtab_node::get (base2);
2074 if (!node2)
2075 return 0;
2077 ret = node1->equal_address_to (node2, true);
2078 return ret;
2081 /* Same as compare_base_decls but for SYMBOL_REF. */
2083 static int
2084 compare_base_symbol_refs (const_rtx x_base, const_rtx y_base)
2086 tree x_decl = SYMBOL_REF_DECL (x_base);
2087 tree y_decl = SYMBOL_REF_DECL (y_base);
2088 bool binds_def = true;
2090 if (XSTR (x_base, 0) == XSTR (y_base, 0))
2091 return 1;
2092 if (x_decl && y_decl)
2093 return compare_base_decls (x_decl, y_decl);
2094 if (x_decl || y_decl)
2096 if (!x_decl)
2098 std::swap (x_decl, y_decl);
2099 std::swap (x_base, y_base);
2101 /* We handle specially only section anchors and assume that other
2102 labels may overlap with user variables in an arbitrary way. */
2103 if (!SYMBOL_REF_HAS_BLOCK_INFO_P (y_base))
2104 return -1;
2105 /* Anchors contains static VAR_DECLs and CONST_DECLs. We are safe
2106 to ignore CONST_DECLs because they are readonly. */
2107 if (!VAR_P (x_decl)
2108 || (!TREE_STATIC (x_decl) && !TREE_PUBLIC (x_decl)))
2109 return 0;
2111 symtab_node *x_node = symtab_node::get_create (x_decl)
2112 ->ultimate_alias_target ();
2113 /* External variable can not be in section anchor. */
2114 if (!x_node->definition)
2115 return 0;
2116 x_base = XEXP (DECL_RTL (x_node->decl), 0);
2117 /* If not in anchor, we can disambiguate. */
2118 if (!SYMBOL_REF_HAS_BLOCK_INFO_P (x_base))
2119 return 0;
2121 /* We have an alias of anchored variable. If it can be interposed;
2122 we must assume it may or may not alias its anchor. */
2123 binds_def = decl_binds_to_current_def_p (x_decl);
2125 /* If we have variable in section anchor, we can compare by offset. */
2126 if (SYMBOL_REF_HAS_BLOCK_INFO_P (x_base)
2127 && SYMBOL_REF_HAS_BLOCK_INFO_P (y_base))
2129 if (SYMBOL_REF_BLOCK (x_base) != SYMBOL_REF_BLOCK (y_base))
2130 return 0;
2131 if (SYMBOL_REF_BLOCK_OFFSET (x_base) == SYMBOL_REF_BLOCK_OFFSET (y_base))
2132 return binds_def ? 1 : -1;
2133 if (SYMBOL_REF_ANCHOR_P (x_base) != SYMBOL_REF_ANCHOR_P (y_base))
2134 return -1;
2135 return 0;
2137 /* In general we assume that memory locations pointed to by different labels
2138 may overlap in undefined ways. */
2139 return -1;
2142 /* Return 0 if the addresses X and Y are known to point to different
2143 objects, 1 if they might be pointers to the same object. */
2145 static int
2146 base_alias_check (rtx x, rtx x_base, rtx y, rtx y_base,
2147 machine_mode x_mode, machine_mode y_mode)
2149 /* If the address itself has no known base see if a known equivalent
2150 value has one. If either address still has no known base, nothing
2151 is known about aliasing. */
2152 if (x_base == 0)
2154 rtx x_c;
2156 if (! flag_expensive_optimizations || (x_c = canon_rtx (x)) == x)
2157 return 1;
2159 x_base = find_base_term (x_c);
2160 if (x_base == 0)
2161 return 1;
2164 if (y_base == 0)
2166 rtx y_c;
2167 if (! flag_expensive_optimizations || (y_c = canon_rtx (y)) == y)
2168 return 1;
2170 y_base = find_base_term (y_c);
2171 if (y_base == 0)
2172 return 1;
2175 /* If the base addresses are equal nothing is known about aliasing. */
2176 if (rtx_equal_p (x_base, y_base))
2177 return 1;
2179 /* The base addresses are different expressions. If they are not accessed
2180 via AND, there is no conflict. We can bring knowledge of object
2181 alignment into play here. For example, on alpha, "char a, b;" can
2182 alias one another, though "char a; long b;" cannot. AND addresses may
2183 implicitly alias surrounding objects; i.e. unaligned access in DImode
2184 via AND address can alias all surrounding object types except those
2185 with aligment 8 or higher. */
2186 if (GET_CODE (x) == AND && GET_CODE (y) == AND)
2187 return 1;
2188 if (GET_CODE (x) == AND
2189 && (!CONST_INT_P (XEXP (x, 1))
2190 || (int) GET_MODE_UNIT_SIZE (y_mode) < -INTVAL (XEXP (x, 1))))
2191 return 1;
2192 if (GET_CODE (y) == AND
2193 && (!CONST_INT_P (XEXP (y, 1))
2194 || (int) GET_MODE_UNIT_SIZE (x_mode) < -INTVAL (XEXP (y, 1))))
2195 return 1;
2197 /* Differing symbols not accessed via AND never alias. */
2198 if (GET_CODE (x_base) == SYMBOL_REF && GET_CODE (y_base) == SYMBOL_REF)
2199 return compare_base_symbol_refs (x_base, y_base) != 0;
2201 if (GET_CODE (x_base) != ADDRESS && GET_CODE (y_base) != ADDRESS)
2202 return 0;
2204 if (unique_base_value_p (x_base) || unique_base_value_p (y_base))
2205 return 0;
2207 return 1;
2210 /* Return TRUE if EXPR refers to a VALUE whose uid is greater than
2211 (or equal to) that of V. */
2213 static bool
2214 refs_newer_value_p (const_rtx expr, rtx v)
2216 int minuid = CSELIB_VAL_PTR (v)->uid;
2217 subrtx_iterator::array_type array;
2218 FOR_EACH_SUBRTX (iter, array, expr, NONCONST)
2219 if (GET_CODE (*iter) == VALUE && CSELIB_VAL_PTR (*iter)->uid >= minuid)
2220 return true;
2221 return false;
2224 /* Convert the address X into something we can use. This is done by returning
2225 it unchanged unless it is a VALUE or VALUE +/- constant; for VALUE
2226 we call cselib to get a more useful rtx. */
2229 get_addr (rtx x)
2231 cselib_val *v;
2232 struct elt_loc_list *l;
2234 if (GET_CODE (x) != VALUE)
2236 if ((GET_CODE (x) == PLUS || GET_CODE (x) == MINUS)
2237 && GET_CODE (XEXP (x, 0)) == VALUE
2238 && CONST_SCALAR_INT_P (XEXP (x, 1)))
2240 rtx op0 = get_addr (XEXP (x, 0));
2241 if (op0 != XEXP (x, 0))
2243 if (GET_CODE (x) == PLUS
2244 && GET_CODE (XEXP (x, 1)) == CONST_INT)
2245 return plus_constant (GET_MODE (x), op0, INTVAL (XEXP (x, 1)));
2246 return simplify_gen_binary (GET_CODE (x), GET_MODE (x),
2247 op0, XEXP (x, 1));
2250 return x;
2252 v = CSELIB_VAL_PTR (x);
2253 if (v)
2255 bool have_equivs = cselib_have_permanent_equivalences ();
2256 if (have_equivs)
2257 v = canonical_cselib_val (v);
2258 for (l = v->locs; l; l = l->next)
2259 if (CONSTANT_P (l->loc))
2260 return l->loc;
2261 for (l = v->locs; l; l = l->next)
2262 if (!REG_P (l->loc) && !MEM_P (l->loc)
2263 /* Avoid infinite recursion when potentially dealing with
2264 var-tracking artificial equivalences, by skipping the
2265 equivalences themselves, and not choosing expressions
2266 that refer to newer VALUEs. */
2267 && (!have_equivs
2268 || (GET_CODE (l->loc) != VALUE
2269 && !refs_newer_value_p (l->loc, x))))
2270 return l->loc;
2271 if (have_equivs)
2273 for (l = v->locs; l; l = l->next)
2274 if (REG_P (l->loc)
2275 || (GET_CODE (l->loc) != VALUE
2276 && !refs_newer_value_p (l->loc, x)))
2277 return l->loc;
2278 /* Return the canonical value. */
2279 return v->val_rtx;
2281 if (v->locs)
2282 return v->locs->loc;
2284 return x;
2287 /* Return the address of the (N_REFS + 1)th memory reference to ADDR
2288 where SIZE is the size in bytes of the memory reference. If ADDR
2289 is not modified by the memory reference then ADDR is returned. */
2291 static rtx
2292 addr_side_effect_eval (rtx addr, int size, int n_refs)
2294 int offset = 0;
2296 switch (GET_CODE (addr))
2298 case PRE_INC:
2299 offset = (n_refs + 1) * size;
2300 break;
2301 case PRE_DEC:
2302 offset = -(n_refs + 1) * size;
2303 break;
2304 case POST_INC:
2305 offset = n_refs * size;
2306 break;
2307 case POST_DEC:
2308 offset = -n_refs * size;
2309 break;
2311 default:
2312 return addr;
2315 if (offset)
2316 addr = gen_rtx_PLUS (GET_MODE (addr), XEXP (addr, 0),
2317 gen_int_mode (offset, GET_MODE (addr)));
2318 else
2319 addr = XEXP (addr, 0);
2320 addr = canon_rtx (addr);
2322 return addr;
2325 /* Return TRUE if an object X sized at XSIZE bytes and another object
2326 Y sized at YSIZE bytes, starting C bytes after X, may overlap. If
2327 any of the sizes is zero, assume an overlap, otherwise use the
2328 absolute value of the sizes as the actual sizes. */
2330 static inline bool
2331 offset_overlap_p (HOST_WIDE_INT c, int xsize, int ysize)
2333 return (xsize == 0 || ysize == 0
2334 || (c >= 0
2335 ? (abs (xsize) > c)
2336 : (abs (ysize) > -c)));
2339 /* Return one if X and Y (memory addresses) reference the
2340 same location in memory or if the references overlap.
2341 Return zero if they do not overlap, else return
2342 minus one in which case they still might reference the same location.
2344 C is an offset accumulator. When
2345 C is nonzero, we are testing aliases between X and Y + C.
2346 XSIZE is the size in bytes of the X reference,
2347 similarly YSIZE is the size in bytes for Y.
2348 Expect that canon_rtx has been already called for X and Y.
2350 If XSIZE or YSIZE is zero, we do not know the amount of memory being
2351 referenced (the reference was BLKmode), so make the most pessimistic
2352 assumptions.
2354 If XSIZE or YSIZE is negative, we may access memory outside the object
2355 being referenced as a side effect. This can happen when using AND to
2356 align memory references, as is done on the Alpha.
2358 Nice to notice that varying addresses cannot conflict with fp if no
2359 local variables had their addresses taken, but that's too hard now.
2361 ??? Contrary to the tree alias oracle this does not return
2362 one for X + non-constant and Y + non-constant when X and Y are equal.
2363 If that is fixed the TBAA hack for union type-punning can be removed. */
2365 static int
2366 memrefs_conflict_p (int xsize, rtx x, int ysize, rtx y, HOST_WIDE_INT c)
2368 if (GET_CODE (x) == VALUE)
2370 if (REG_P (y))
2372 struct elt_loc_list *l = NULL;
2373 if (CSELIB_VAL_PTR (x))
2374 for (l = canonical_cselib_val (CSELIB_VAL_PTR (x))->locs;
2375 l; l = l->next)
2376 if (REG_P (l->loc) && rtx_equal_for_memref_p (l->loc, y))
2377 break;
2378 if (l)
2379 x = y;
2380 else
2381 x = get_addr (x);
2383 /* Don't call get_addr if y is the same VALUE. */
2384 else if (x != y)
2385 x = get_addr (x);
2387 if (GET_CODE (y) == VALUE)
2389 if (REG_P (x))
2391 struct elt_loc_list *l = NULL;
2392 if (CSELIB_VAL_PTR (y))
2393 for (l = canonical_cselib_val (CSELIB_VAL_PTR (y))->locs;
2394 l; l = l->next)
2395 if (REG_P (l->loc) && rtx_equal_for_memref_p (l->loc, x))
2396 break;
2397 if (l)
2398 y = x;
2399 else
2400 y = get_addr (y);
2402 /* Don't call get_addr if x is the same VALUE. */
2403 else if (y != x)
2404 y = get_addr (y);
2406 if (GET_CODE (x) == HIGH)
2407 x = XEXP (x, 0);
2408 else if (GET_CODE (x) == LO_SUM)
2409 x = XEXP (x, 1);
2410 else
2411 x = addr_side_effect_eval (x, abs (xsize), 0);
2412 if (GET_CODE (y) == HIGH)
2413 y = XEXP (y, 0);
2414 else if (GET_CODE (y) == LO_SUM)
2415 y = XEXP (y, 1);
2416 else
2417 y = addr_side_effect_eval (y, abs (ysize), 0);
2419 if (GET_CODE (x) == SYMBOL_REF && GET_CODE (y) == SYMBOL_REF)
2421 int cmp = compare_base_symbol_refs (x,y);
2423 /* If both decls are the same, decide by offsets. */
2424 if (cmp == 1)
2425 return offset_overlap_p (c, xsize, ysize);
2426 /* Assume a potential overlap for symbolic addresses that went
2427 through alignment adjustments (i.e., that have negative
2428 sizes), because we can't know how far they are from each
2429 other. */
2430 if (xsize < 0 || ysize < 0)
2431 return -1;
2432 /* If decls are different or we know by offsets that there is no overlap,
2433 we win. */
2434 if (!cmp || !offset_overlap_p (c, xsize, ysize))
2435 return 0;
2436 /* Decls may or may not be different and offsets overlap....*/
2437 return -1;
2439 else if (rtx_equal_for_memref_p (x, y))
2441 return offset_overlap_p (c, xsize, ysize);
2444 /* This code used to check for conflicts involving stack references and
2445 globals but the base address alias code now handles these cases. */
2447 if (GET_CODE (x) == PLUS)
2449 /* The fact that X is canonicalized means that this
2450 PLUS rtx is canonicalized. */
2451 rtx x0 = XEXP (x, 0);
2452 rtx x1 = XEXP (x, 1);
2454 /* However, VALUEs might end up in different positions even in
2455 canonical PLUSes. Comparing their addresses is enough. */
2456 if (x0 == y)
2457 return memrefs_conflict_p (xsize, x1, ysize, const0_rtx, c);
2458 else if (x1 == y)
2459 return memrefs_conflict_p (xsize, x0, ysize, const0_rtx, c);
2461 if (GET_CODE (y) == PLUS)
2463 /* The fact that Y is canonicalized means that this
2464 PLUS rtx is canonicalized. */
2465 rtx y0 = XEXP (y, 0);
2466 rtx y1 = XEXP (y, 1);
2468 if (x0 == y1)
2469 return memrefs_conflict_p (xsize, x1, ysize, y0, c);
2470 if (x1 == y0)
2471 return memrefs_conflict_p (xsize, x0, ysize, y1, c);
2473 if (rtx_equal_for_memref_p (x1, y1))
2474 return memrefs_conflict_p (xsize, x0, ysize, y0, c);
2475 if (rtx_equal_for_memref_p (x0, y0))
2476 return memrefs_conflict_p (xsize, x1, ysize, y1, c);
2477 if (CONST_INT_P (x1))
2479 if (CONST_INT_P (y1))
2480 return memrefs_conflict_p (xsize, x0, ysize, y0,
2481 c - INTVAL (x1) + INTVAL (y1));
2482 else
2483 return memrefs_conflict_p (xsize, x0, ysize, y,
2484 c - INTVAL (x1));
2486 else if (CONST_INT_P (y1))
2487 return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1));
2489 return -1;
2491 else if (CONST_INT_P (x1))
2492 return memrefs_conflict_p (xsize, x0, ysize, y, c - INTVAL (x1));
2494 else if (GET_CODE (y) == PLUS)
2496 /* The fact that Y is canonicalized means that this
2497 PLUS rtx is canonicalized. */
2498 rtx y0 = XEXP (y, 0);
2499 rtx y1 = XEXP (y, 1);
2501 if (x == y0)
2502 return memrefs_conflict_p (xsize, const0_rtx, ysize, y1, c);
2503 if (x == y1)
2504 return memrefs_conflict_p (xsize, const0_rtx, ysize, y0, c);
2506 if (CONST_INT_P (y1))
2507 return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1));
2508 else
2509 return -1;
2512 if (GET_CODE (x) == GET_CODE (y))
2513 switch (GET_CODE (x))
2515 case MULT:
2517 /* Handle cases where we expect the second operands to be the
2518 same, and check only whether the first operand would conflict
2519 or not. */
2520 rtx x0, y0;
2521 rtx x1 = canon_rtx (XEXP (x, 1));
2522 rtx y1 = canon_rtx (XEXP (y, 1));
2523 if (! rtx_equal_for_memref_p (x1, y1))
2524 return -1;
2525 x0 = canon_rtx (XEXP (x, 0));
2526 y0 = canon_rtx (XEXP (y, 0));
2527 if (rtx_equal_for_memref_p (x0, y0))
2528 return offset_overlap_p (c, xsize, ysize);
2530 /* Can't properly adjust our sizes. */
2531 if (!CONST_INT_P (x1))
2532 return -1;
2533 xsize /= INTVAL (x1);
2534 ysize /= INTVAL (x1);
2535 c /= INTVAL (x1);
2536 return memrefs_conflict_p (xsize, x0, ysize, y0, c);
2539 default:
2540 break;
2543 /* Deal with alignment ANDs by adjusting offset and size so as to
2544 cover the maximum range, without taking any previously known
2545 alignment into account. Make a size negative after such an
2546 adjustments, so that, if we end up with e.g. two SYMBOL_REFs, we
2547 assume a potential overlap, because they may end up in contiguous
2548 memory locations and the stricter-alignment access may span over
2549 part of both. */
2550 if (GET_CODE (x) == AND && CONST_INT_P (XEXP (x, 1)))
2552 HOST_WIDE_INT sc = INTVAL (XEXP (x, 1));
2553 unsigned HOST_WIDE_INT uc = sc;
2554 if (sc < 0 && pow2_or_zerop (-uc))
2556 if (xsize > 0)
2557 xsize = -xsize;
2558 if (xsize)
2559 xsize += sc + 1;
2560 c -= sc + 1;
2561 return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)),
2562 ysize, y, c);
2565 if (GET_CODE (y) == AND && CONST_INT_P (XEXP (y, 1)))
2567 HOST_WIDE_INT sc = INTVAL (XEXP (y, 1));
2568 unsigned HOST_WIDE_INT uc = sc;
2569 if (sc < 0 && pow2_or_zerop (-uc))
2571 if (ysize > 0)
2572 ysize = -ysize;
2573 if (ysize)
2574 ysize += sc + 1;
2575 c += sc + 1;
2576 return memrefs_conflict_p (xsize, x,
2577 ysize, canon_rtx (XEXP (y, 0)), c);
2581 if (CONSTANT_P (x))
2583 if (CONST_INT_P (x) && CONST_INT_P (y))
2585 c += (INTVAL (y) - INTVAL (x));
2586 return offset_overlap_p (c, xsize, ysize);
2589 if (GET_CODE (x) == CONST)
2591 if (GET_CODE (y) == CONST)
2592 return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)),
2593 ysize, canon_rtx (XEXP (y, 0)), c);
2594 else
2595 return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)),
2596 ysize, y, c);
2598 if (GET_CODE (y) == CONST)
2599 return memrefs_conflict_p (xsize, x, ysize,
2600 canon_rtx (XEXP (y, 0)), c);
2602 /* Assume a potential overlap for symbolic addresses that went
2603 through alignment adjustments (i.e., that have negative
2604 sizes), because we can't know how far they are from each
2605 other. */
2606 if (CONSTANT_P (y))
2607 return (xsize < 0 || ysize < 0 || offset_overlap_p (c, xsize, ysize));
2609 return -1;
2612 return -1;
2615 /* Functions to compute memory dependencies.
2617 Since we process the insns in execution order, we can build tables
2618 to keep track of what registers are fixed (and not aliased), what registers
2619 are varying in known ways, and what registers are varying in unknown
2620 ways.
2622 If both memory references are volatile, then there must always be a
2623 dependence between the two references, since their order can not be
2624 changed. A volatile and non-volatile reference can be interchanged
2625 though.
2627 We also must allow AND addresses, because they may generate accesses
2628 outside the object being referenced. This is used to generate aligned
2629 addresses from unaligned addresses, for instance, the alpha
2630 storeqi_unaligned pattern. */
2632 /* Read dependence: X is read after read in MEM takes place. There can
2633 only be a dependence here if both reads are volatile, or if either is
2634 an explicit barrier. */
2637 read_dependence (const_rtx mem, const_rtx x)
2639 if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem))
2640 return true;
2641 if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER
2642 || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER)
2643 return true;
2644 return false;
2647 /* Look at the bottom of the COMPONENT_REF list for a DECL, and return it. */
2649 static tree
2650 decl_for_component_ref (tree x)
2654 x = TREE_OPERAND (x, 0);
2656 while (x && TREE_CODE (x) == COMPONENT_REF);
2658 return x && DECL_P (x) ? x : NULL_TREE;
2661 /* Walk up the COMPONENT_REF list in X and adjust *OFFSET to compensate
2662 for the offset of the field reference. *KNOWN_P says whether the
2663 offset is known. */
2665 static void
2666 adjust_offset_for_component_ref (tree x, bool *known_p,
2667 HOST_WIDE_INT *offset)
2669 if (!*known_p)
2670 return;
2673 tree xoffset = component_ref_field_offset (x);
2674 tree field = TREE_OPERAND (x, 1);
2675 if (TREE_CODE (xoffset) != INTEGER_CST)
2677 *known_p = false;
2678 return;
2681 offset_int woffset
2682 = (wi::to_offset (xoffset)
2683 + (wi::to_offset (DECL_FIELD_BIT_OFFSET (field))
2684 >> LOG2_BITS_PER_UNIT));
2685 if (!wi::fits_uhwi_p (woffset))
2687 *known_p = false;
2688 return;
2690 *offset += woffset.to_uhwi ();
2692 x = TREE_OPERAND (x, 0);
2694 while (x && TREE_CODE (x) == COMPONENT_REF);
2697 /* Return nonzero if we can determine the exprs corresponding to memrefs
2698 X and Y and they do not overlap.
2699 If LOOP_VARIANT is set, skip offset-based disambiguation */
2702 nonoverlapping_memrefs_p (const_rtx x, const_rtx y, bool loop_invariant)
2704 tree exprx = MEM_EXPR (x), expry = MEM_EXPR (y);
2705 rtx rtlx, rtly;
2706 rtx basex, basey;
2707 bool moffsetx_known_p, moffsety_known_p;
2708 HOST_WIDE_INT moffsetx = 0, moffsety = 0;
2709 HOST_WIDE_INT offsetx = 0, offsety = 0, sizex, sizey;
2711 /* Unless both have exprs, we can't tell anything. */
2712 if (exprx == 0 || expry == 0)
2713 return 0;
2715 /* For spill-slot accesses make sure we have valid offsets. */
2716 if ((exprx == get_spill_slot_decl (false)
2717 && ! MEM_OFFSET_KNOWN_P (x))
2718 || (expry == get_spill_slot_decl (false)
2719 && ! MEM_OFFSET_KNOWN_P (y)))
2720 return 0;
2722 /* If the field reference test failed, look at the DECLs involved. */
2723 moffsetx_known_p = MEM_OFFSET_KNOWN_P (x);
2724 if (moffsetx_known_p)
2725 moffsetx = MEM_OFFSET (x);
2726 if (TREE_CODE (exprx) == COMPONENT_REF)
2728 tree t = decl_for_component_ref (exprx);
2729 if (! t)
2730 return 0;
2731 adjust_offset_for_component_ref (exprx, &moffsetx_known_p, &moffsetx);
2732 exprx = t;
2735 moffsety_known_p = MEM_OFFSET_KNOWN_P (y);
2736 if (moffsety_known_p)
2737 moffsety = MEM_OFFSET (y);
2738 if (TREE_CODE (expry) == COMPONENT_REF)
2740 tree t = decl_for_component_ref (expry);
2741 if (! t)
2742 return 0;
2743 adjust_offset_for_component_ref (expry, &moffsety_known_p, &moffsety);
2744 expry = t;
2747 if (! DECL_P (exprx) || ! DECL_P (expry))
2748 return 0;
2750 /* If we refer to different gimple registers, or one gimple register
2751 and one non-gimple-register, we know they can't overlap. First,
2752 gimple registers don't have their addresses taken. Now, there
2753 could be more than one stack slot for (different versions of) the
2754 same gimple register, but we can presumably tell they don't
2755 overlap based on offsets from stack base addresses elsewhere.
2756 It's important that we don't proceed to DECL_RTL, because gimple
2757 registers may not pass DECL_RTL_SET_P, and make_decl_rtl won't be
2758 able to do anything about them since no SSA information will have
2759 remained to guide it. */
2760 if (is_gimple_reg (exprx) || is_gimple_reg (expry))
2761 return exprx != expry
2762 || (moffsetx_known_p && moffsety_known_p
2763 && MEM_SIZE_KNOWN_P (x) && MEM_SIZE_KNOWN_P (y)
2764 && !offset_overlap_p (moffsety - moffsetx,
2765 MEM_SIZE (x), MEM_SIZE (y)));
2767 /* With invalid code we can end up storing into the constant pool.
2768 Bail out to avoid ICEing when creating RTL for this.
2769 See gfortran.dg/lto/20091028-2_0.f90. */
2770 if (TREE_CODE (exprx) == CONST_DECL
2771 || TREE_CODE (expry) == CONST_DECL)
2772 return 1;
2774 /* If one decl is known to be a function or label in a function and
2775 the other is some kind of data, they can't overlap. */
2776 if ((TREE_CODE (exprx) == FUNCTION_DECL
2777 || TREE_CODE (exprx) == LABEL_DECL)
2778 != (TREE_CODE (expry) == FUNCTION_DECL
2779 || TREE_CODE (expry) == LABEL_DECL))
2780 return 1;
2782 /* If either of the decls doesn't have DECL_RTL set (e.g. marked as
2783 living in multiple places), we can't tell anything. Exception
2784 are FUNCTION_DECLs for which we can create DECL_RTL on demand. */
2785 if ((!DECL_RTL_SET_P (exprx) && TREE_CODE (exprx) != FUNCTION_DECL)
2786 || (!DECL_RTL_SET_P (expry) && TREE_CODE (expry) != FUNCTION_DECL))
2787 return 0;
2789 rtlx = DECL_RTL (exprx);
2790 rtly = DECL_RTL (expry);
2792 /* If either RTL is not a MEM, it must be a REG or CONCAT, meaning they
2793 can't overlap unless they are the same because we never reuse that part
2794 of the stack frame used for locals for spilled pseudos. */
2795 if ((!MEM_P (rtlx) || !MEM_P (rtly))
2796 && ! rtx_equal_p (rtlx, rtly))
2797 return 1;
2799 /* If we have MEMs referring to different address spaces (which can
2800 potentially overlap), we cannot easily tell from the addresses
2801 whether the references overlap. */
2802 if (MEM_P (rtlx) && MEM_P (rtly)
2803 && MEM_ADDR_SPACE (rtlx) != MEM_ADDR_SPACE (rtly))
2804 return 0;
2806 /* Get the base and offsets of both decls. If either is a register, we
2807 know both are and are the same, so use that as the base. The only
2808 we can avoid overlap is if we can deduce that they are nonoverlapping
2809 pieces of that decl, which is very rare. */
2810 basex = MEM_P (rtlx) ? XEXP (rtlx, 0) : rtlx;
2811 if (GET_CODE (basex) == PLUS && CONST_INT_P (XEXP (basex, 1)))
2812 offsetx = INTVAL (XEXP (basex, 1)), basex = XEXP (basex, 0);
2814 basey = MEM_P (rtly) ? XEXP (rtly, 0) : rtly;
2815 if (GET_CODE (basey) == PLUS && CONST_INT_P (XEXP (basey, 1)))
2816 offsety = INTVAL (XEXP (basey, 1)), basey = XEXP (basey, 0);
2818 /* If the bases are different, we know they do not overlap if both
2819 are constants or if one is a constant and the other a pointer into the
2820 stack frame. Otherwise a different base means we can't tell if they
2821 overlap or not. */
2822 if (compare_base_decls (exprx, expry) == 0)
2823 return ((CONSTANT_P (basex) && CONSTANT_P (basey))
2824 || (CONSTANT_P (basex) && REG_P (basey)
2825 && REGNO_PTR_FRAME_P (REGNO (basey)))
2826 || (CONSTANT_P (basey) && REG_P (basex)
2827 && REGNO_PTR_FRAME_P (REGNO (basex))));
2829 /* Offset based disambiguation not appropriate for loop invariant */
2830 if (loop_invariant)
2831 return 0;
2833 /* Offset based disambiguation is OK even if we do not know that the
2834 declarations are necessarily different
2835 (i.e. compare_base_decls (exprx, expry) == -1) */
2837 sizex = (!MEM_P (rtlx) ? (int) GET_MODE_SIZE (GET_MODE (rtlx))
2838 : MEM_SIZE_KNOWN_P (rtlx) ? MEM_SIZE (rtlx)
2839 : -1);
2840 sizey = (!MEM_P (rtly) ? (int) GET_MODE_SIZE (GET_MODE (rtly))
2841 : MEM_SIZE_KNOWN_P (rtly) ? MEM_SIZE (rtly)
2842 : -1);
2844 /* If we have an offset for either memref, it can update the values computed
2845 above. */
2846 if (moffsetx_known_p)
2847 offsetx += moffsetx, sizex -= moffsetx;
2848 if (moffsety_known_p)
2849 offsety += moffsety, sizey -= moffsety;
2851 /* If a memref has both a size and an offset, we can use the smaller size.
2852 We can't do this if the offset isn't known because we must view this
2853 memref as being anywhere inside the DECL's MEM. */
2854 if (MEM_SIZE_KNOWN_P (x) && moffsetx_known_p)
2855 sizex = MEM_SIZE (x);
2856 if (MEM_SIZE_KNOWN_P (y) && moffsety_known_p)
2857 sizey = MEM_SIZE (y);
2859 /* Put the values of the memref with the lower offset in X's values. */
2860 if (offsetx > offsety)
2862 std::swap (offsetx, offsety);
2863 std::swap (sizex, sizey);
2866 /* If we don't know the size of the lower-offset value, we can't tell
2867 if they conflict. Otherwise, we do the test. */
2868 return sizex >= 0 && offsety >= offsetx + sizex;
2871 /* Helper for true_dependence and canon_true_dependence.
2872 Checks for true dependence: X is read after store in MEM takes place.
2874 If MEM_CANONICALIZED is FALSE, then X_ADDR and MEM_ADDR should be
2875 NULL_RTX, and the canonical addresses of MEM and X are both computed
2876 here. If MEM_CANONICALIZED, then MEM must be already canonicalized.
2878 If X_ADDR is non-NULL, it is used in preference of XEXP (x, 0).
2880 Returns 1 if there is a true dependence, 0 otherwise. */
2882 static int
2883 true_dependence_1 (const_rtx mem, machine_mode mem_mode, rtx mem_addr,
2884 const_rtx x, rtx x_addr, bool mem_canonicalized)
2886 rtx true_mem_addr;
2887 rtx base;
2888 int ret;
2890 gcc_checking_assert (mem_canonicalized ? (mem_addr != NULL_RTX)
2891 : (mem_addr == NULL_RTX && x_addr == NULL_RTX));
2893 if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem))
2894 return 1;
2896 /* (mem:BLK (scratch)) is a special mechanism to conflict with everything.
2897 This is used in epilogue deallocation functions, and in cselib. */
2898 if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH)
2899 return 1;
2900 if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH)
2901 return 1;
2902 if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER
2903 || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER)
2904 return 1;
2906 if (! x_addr)
2907 x_addr = XEXP (x, 0);
2908 x_addr = get_addr (x_addr);
2910 if (! mem_addr)
2912 mem_addr = XEXP (mem, 0);
2913 if (mem_mode == VOIDmode)
2914 mem_mode = GET_MODE (mem);
2916 true_mem_addr = get_addr (mem_addr);
2918 /* Read-only memory is by definition never modified, and therefore can't
2919 conflict with anything. However, don't assume anything when AND
2920 addresses are involved and leave to the code below to determine
2921 dependence. We don't expect to find read-only set on MEM, but
2922 stupid user tricks can produce them, so don't die. */
2923 if (MEM_READONLY_P (x)
2924 && GET_CODE (x_addr) != AND
2925 && GET_CODE (true_mem_addr) != AND)
2926 return 0;
2928 /* If we have MEMs referring to different address spaces (which can
2929 potentially overlap), we cannot easily tell from the addresses
2930 whether the references overlap. */
2931 if (MEM_ADDR_SPACE (mem) != MEM_ADDR_SPACE (x))
2932 return 1;
2934 base = find_base_term (x_addr);
2935 if (base && (GET_CODE (base) == LABEL_REF
2936 || (GET_CODE (base) == SYMBOL_REF
2937 && CONSTANT_POOL_ADDRESS_P (base))))
2938 return 0;
2940 rtx mem_base = find_base_term (true_mem_addr);
2941 if (! base_alias_check (x_addr, base, true_mem_addr, mem_base,
2942 GET_MODE (x), mem_mode))
2943 return 0;
2945 x_addr = canon_rtx (x_addr);
2946 if (!mem_canonicalized)
2947 mem_addr = canon_rtx (true_mem_addr);
2949 if ((ret = memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr,
2950 SIZE_FOR_MODE (x), x_addr, 0)) != -1)
2951 return ret;
2953 if (mems_in_disjoint_alias_sets_p (x, mem))
2954 return 0;
2956 if (nonoverlapping_memrefs_p (mem, x, false))
2957 return 0;
2959 return rtx_refs_may_alias_p (x, mem, true);
2962 /* True dependence: X is read after store in MEM takes place. */
2965 true_dependence (const_rtx mem, machine_mode mem_mode, const_rtx x)
2967 return true_dependence_1 (mem, mem_mode, NULL_RTX,
2968 x, NULL_RTX, /*mem_canonicalized=*/false);
2971 /* Canonical true dependence: X is read after store in MEM takes place.
2972 Variant of true_dependence which assumes MEM has already been
2973 canonicalized (hence we no longer do that here).
2974 The mem_addr argument has been added, since true_dependence_1 computed
2975 this value prior to canonicalizing. */
2978 canon_true_dependence (const_rtx mem, machine_mode mem_mode, rtx mem_addr,
2979 const_rtx x, rtx x_addr)
2981 return true_dependence_1 (mem, mem_mode, mem_addr,
2982 x, x_addr, /*mem_canonicalized=*/true);
2985 /* Returns nonzero if a write to X might alias a previous read from
2986 (or, if WRITEP is true, a write to) MEM.
2987 If X_CANONCALIZED is true, then X_ADDR is the canonicalized address of X,
2988 and X_MODE the mode for that access.
2989 If MEM_CANONICALIZED is true, MEM is canonicalized. */
2991 static int
2992 write_dependence_p (const_rtx mem,
2993 const_rtx x, machine_mode x_mode, rtx x_addr,
2994 bool mem_canonicalized, bool x_canonicalized, bool writep)
2996 rtx mem_addr;
2997 rtx true_mem_addr, true_x_addr;
2998 rtx base;
2999 int ret;
3001 gcc_checking_assert (x_canonicalized
3002 ? (x_addr != NULL_RTX && x_mode != VOIDmode)
3003 : (x_addr == NULL_RTX && x_mode == VOIDmode));
3005 if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem))
3006 return 1;
3008 /* (mem:BLK (scratch)) is a special mechanism to conflict with everything.
3009 This is used in epilogue deallocation functions. */
3010 if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH)
3011 return 1;
3012 if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH)
3013 return 1;
3014 if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER
3015 || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER)
3016 return 1;
3018 if (!x_addr)
3019 x_addr = XEXP (x, 0);
3020 true_x_addr = get_addr (x_addr);
3022 mem_addr = XEXP (mem, 0);
3023 true_mem_addr = get_addr (mem_addr);
3025 /* A read from read-only memory can't conflict with read-write memory.
3026 Don't assume anything when AND addresses are involved and leave to
3027 the code below to determine dependence. */
3028 if (!writep
3029 && MEM_READONLY_P (mem)
3030 && GET_CODE (true_x_addr) != AND
3031 && GET_CODE (true_mem_addr) != AND)
3032 return 0;
3034 /* If we have MEMs referring to different address spaces (which can
3035 potentially overlap), we cannot easily tell from the addresses
3036 whether the references overlap. */
3037 if (MEM_ADDR_SPACE (mem) != MEM_ADDR_SPACE (x))
3038 return 1;
3040 base = find_base_term (true_mem_addr);
3041 if (! writep
3042 && base
3043 && (GET_CODE (base) == LABEL_REF
3044 || (GET_CODE (base) == SYMBOL_REF
3045 && CONSTANT_POOL_ADDRESS_P (base))))
3046 return 0;
3048 rtx x_base = find_base_term (true_x_addr);
3049 if (! base_alias_check (true_x_addr, x_base, true_mem_addr, base,
3050 GET_MODE (x), GET_MODE (mem)))
3051 return 0;
3053 if (!x_canonicalized)
3055 x_addr = canon_rtx (true_x_addr);
3056 x_mode = GET_MODE (x);
3058 if (!mem_canonicalized)
3059 mem_addr = canon_rtx (true_mem_addr);
3061 if ((ret = memrefs_conflict_p (SIZE_FOR_MODE (mem), mem_addr,
3062 GET_MODE_SIZE (x_mode), x_addr, 0)) != -1)
3063 return ret;
3065 if (nonoverlapping_memrefs_p (x, mem, false))
3066 return 0;
3068 return rtx_refs_may_alias_p (x, mem, false);
3071 /* Anti dependence: X is written after read in MEM takes place. */
3074 anti_dependence (const_rtx mem, const_rtx x)
3076 return write_dependence_p (mem, x, VOIDmode, NULL_RTX,
3077 /*mem_canonicalized=*/false,
3078 /*x_canonicalized*/false, /*writep=*/false);
3081 /* Likewise, but we already have a canonicalized MEM, and X_ADDR for X.
3082 Also, consider X in X_MODE (which might be from an enclosing
3083 STRICT_LOW_PART / ZERO_EXTRACT).
3084 If MEM_CANONICALIZED is true, MEM is canonicalized. */
3087 canon_anti_dependence (const_rtx mem, bool mem_canonicalized,
3088 const_rtx x, machine_mode x_mode, rtx x_addr)
3090 return write_dependence_p (mem, x, x_mode, x_addr,
3091 mem_canonicalized, /*x_canonicalized=*/true,
3092 /*writep=*/false);
3095 /* Output dependence: X is written after store in MEM takes place. */
3098 output_dependence (const_rtx mem, const_rtx x)
3100 return write_dependence_p (mem, x, VOIDmode, NULL_RTX,
3101 /*mem_canonicalized=*/false,
3102 /*x_canonicalized*/false, /*writep=*/true);
3105 /* Likewise, but we already have a canonicalized MEM, and X_ADDR for X.
3106 Also, consider X in X_MODE (which might be from an enclosing
3107 STRICT_LOW_PART / ZERO_EXTRACT).
3108 If MEM_CANONICALIZED is true, MEM is canonicalized. */
3111 canon_output_dependence (const_rtx mem, bool mem_canonicalized,
3112 const_rtx x, machine_mode x_mode, rtx x_addr)
3114 return write_dependence_p (mem, x, x_mode, x_addr,
3115 mem_canonicalized, /*x_canonicalized=*/true,
3116 /*writep=*/true);
3121 /* Check whether X may be aliased with MEM. Don't do offset-based
3122 memory disambiguation & TBAA. */
3124 may_alias_p (const_rtx mem, const_rtx x)
3126 rtx x_addr, mem_addr;
3128 if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem))
3129 return 1;
3131 /* (mem:BLK (scratch)) is a special mechanism to conflict with everything.
3132 This is used in epilogue deallocation functions. */
3133 if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH)
3134 return 1;
3135 if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH)
3136 return 1;
3137 if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER
3138 || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER)
3139 return 1;
3141 x_addr = XEXP (x, 0);
3142 x_addr = get_addr (x_addr);
3144 mem_addr = XEXP (mem, 0);
3145 mem_addr = get_addr (mem_addr);
3147 /* Read-only memory is by definition never modified, and therefore can't
3148 conflict with anything. However, don't assume anything when AND
3149 addresses are involved and leave to the code below to determine
3150 dependence. We don't expect to find read-only set on MEM, but
3151 stupid user tricks can produce them, so don't die. */
3152 if (MEM_READONLY_P (x)
3153 && GET_CODE (x_addr) != AND
3154 && GET_CODE (mem_addr) != AND)
3155 return 0;
3157 /* If we have MEMs referring to different address spaces (which can
3158 potentially overlap), we cannot easily tell from the addresses
3159 whether the references overlap. */
3160 if (MEM_ADDR_SPACE (mem) != MEM_ADDR_SPACE (x))
3161 return 1;
3163 rtx x_base = find_base_term (x_addr);
3164 rtx mem_base = find_base_term (mem_addr);
3165 if (! base_alias_check (x_addr, x_base, mem_addr, mem_base,
3166 GET_MODE (x), GET_MODE (mem_addr)))
3167 return 0;
3169 if (nonoverlapping_memrefs_p (mem, x, true))
3170 return 0;
3172 /* TBAA not valid for loop_invarint */
3173 return rtx_refs_may_alias_p (x, mem, false);
3176 void
3177 init_alias_target (void)
3179 int i;
3181 if (!arg_base_value)
3182 arg_base_value = gen_rtx_ADDRESS (VOIDmode, 0);
3184 memset (static_reg_base_value, 0, sizeof static_reg_base_value);
3186 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3187 /* Check whether this register can hold an incoming pointer
3188 argument. FUNCTION_ARG_REGNO_P tests outgoing register
3189 numbers, so translate if necessary due to register windows. */
3190 if (FUNCTION_ARG_REGNO_P (OUTGOING_REGNO (i))
3191 && targetm.hard_regno_mode_ok (i, Pmode))
3192 static_reg_base_value[i] = arg_base_value;
3194 static_reg_base_value[STACK_POINTER_REGNUM]
3195 = unique_base_value (UNIQUE_BASE_VALUE_SP);
3196 static_reg_base_value[ARG_POINTER_REGNUM]
3197 = unique_base_value (UNIQUE_BASE_VALUE_ARGP);
3198 static_reg_base_value[FRAME_POINTER_REGNUM]
3199 = unique_base_value (UNIQUE_BASE_VALUE_FP);
3200 if (!HARD_FRAME_POINTER_IS_FRAME_POINTER)
3201 static_reg_base_value[HARD_FRAME_POINTER_REGNUM]
3202 = unique_base_value (UNIQUE_BASE_VALUE_HFP);
3205 /* Set MEMORY_MODIFIED when X modifies DATA (that is assumed
3206 to be memory reference. */
3207 static bool memory_modified;
3208 static void
3209 memory_modified_1 (rtx x, const_rtx pat ATTRIBUTE_UNUSED, void *data)
3211 if (MEM_P (x))
3213 if (anti_dependence (x, (const_rtx)data) || output_dependence (x, (const_rtx)data))
3214 memory_modified = true;
3219 /* Return true when INSN possibly modify memory contents of MEM
3220 (i.e. address can be modified). */
3221 bool
3222 memory_modified_in_insn_p (const_rtx mem, const_rtx insn)
3224 if (!INSN_P (insn))
3225 return false;
3226 /* Conservatively assume all non-readonly MEMs might be modified in
3227 calls. */
3228 if (CALL_P (insn))
3229 return true;
3230 memory_modified = false;
3231 note_stores (PATTERN (insn), memory_modified_1, CONST_CAST_RTX(mem));
3232 return memory_modified;
3235 /* Return TRUE if the destination of a set is rtx identical to
3236 ITEM. */
3237 static inline bool
3238 set_dest_equal_p (const_rtx set, const_rtx item)
3240 rtx dest = SET_DEST (set);
3241 return rtx_equal_p (dest, item);
3244 /* Initialize the aliasing machinery. Initialize the REG_KNOWN_VALUE
3245 array. */
3247 void
3248 init_alias_analysis (void)
3250 unsigned int maxreg = max_reg_num ();
3251 int changed, pass;
3252 int i;
3253 unsigned int ui;
3254 rtx_insn *insn;
3255 rtx val;
3256 int rpo_cnt;
3257 int *rpo;
3259 timevar_push (TV_ALIAS_ANALYSIS);
3261 vec_safe_grow_cleared (reg_known_value, maxreg - FIRST_PSEUDO_REGISTER);
3262 reg_known_equiv_p = sbitmap_alloc (maxreg - FIRST_PSEUDO_REGISTER);
3263 bitmap_clear (reg_known_equiv_p);
3265 /* If we have memory allocated from the previous run, use it. */
3266 if (old_reg_base_value)
3267 reg_base_value = old_reg_base_value;
3269 if (reg_base_value)
3270 reg_base_value->truncate (0);
3272 vec_safe_grow_cleared (reg_base_value, maxreg);
3274 new_reg_base_value = XNEWVEC (rtx, maxreg);
3275 reg_seen = sbitmap_alloc (maxreg);
3277 /* The basic idea is that each pass through this loop will use the
3278 "constant" information from the previous pass to propagate alias
3279 information through another level of assignments.
3281 The propagation is done on the CFG in reverse post-order, to propagate
3282 things forward as far as possible in each iteration.
3284 This could get expensive if the assignment chains are long. Maybe
3285 we should throttle the number of iterations, possibly based on
3286 the optimization level or flag_expensive_optimizations.
3288 We could propagate more information in the first pass by making use
3289 of DF_REG_DEF_COUNT to determine immediately that the alias information
3290 for a pseudo is "constant".
3292 A program with an uninitialized variable can cause an infinite loop
3293 here. Instead of doing a full dataflow analysis to detect such problems
3294 we just cap the number of iterations for the loop.
3296 The state of the arrays for the set chain in question does not matter
3297 since the program has undefined behavior. */
3299 rpo = XNEWVEC (int, n_basic_blocks_for_fn (cfun));
3300 rpo_cnt = pre_and_rev_post_order_compute (NULL, rpo, false);
3302 /* The prologue/epilogue insns are not threaded onto the
3303 insn chain until after reload has completed. Thus,
3304 there is no sense wasting time checking if INSN is in
3305 the prologue/epilogue until after reload has completed. */
3306 bool could_be_prologue_epilogue = ((targetm.have_prologue ()
3307 || targetm.have_epilogue ())
3308 && reload_completed);
3310 pass = 0;
3313 /* Assume nothing will change this iteration of the loop. */
3314 changed = 0;
3316 /* We want to assign the same IDs each iteration of this loop, so
3317 start counting from one each iteration of the loop. */
3318 unique_id = 1;
3320 /* We're at the start of the function each iteration through the
3321 loop, so we're copying arguments. */
3322 copying_arguments = true;
3324 /* Wipe the potential alias information clean for this pass. */
3325 memset (new_reg_base_value, 0, maxreg * sizeof (rtx));
3327 /* Wipe the reg_seen array clean. */
3328 bitmap_clear (reg_seen);
3330 /* Initialize the alias information for this pass. */
3331 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
3332 if (static_reg_base_value[i])
3334 new_reg_base_value[i] = static_reg_base_value[i];
3335 bitmap_set_bit (reg_seen, i);
3338 /* Walk the insns adding values to the new_reg_base_value array. */
3339 for (i = 0; i < rpo_cnt; i++)
3341 basic_block bb = BASIC_BLOCK_FOR_FN (cfun, rpo[i]);
3342 FOR_BB_INSNS (bb, insn)
3344 if (NONDEBUG_INSN_P (insn))
3346 rtx note, set;
3348 if (could_be_prologue_epilogue
3349 && prologue_epilogue_contains (insn))
3350 continue;
3352 /* If this insn has a noalias note, process it, Otherwise,
3353 scan for sets. A simple set will have no side effects
3354 which could change the base value of any other register. */
3356 if (GET_CODE (PATTERN (insn)) == SET
3357 && REG_NOTES (insn) != 0
3358 && find_reg_note (insn, REG_NOALIAS, NULL_RTX))
3359 record_set (SET_DEST (PATTERN (insn)), NULL_RTX, NULL);
3360 else
3361 note_stores (PATTERN (insn), record_set, NULL);
3363 set = single_set (insn);
3365 if (set != 0
3366 && REG_P (SET_DEST (set))
3367 && REGNO (SET_DEST (set)) >= FIRST_PSEUDO_REGISTER)
3369 unsigned int regno = REGNO (SET_DEST (set));
3370 rtx src = SET_SRC (set);
3371 rtx t;
3373 note = find_reg_equal_equiv_note (insn);
3374 if (note && REG_NOTE_KIND (note) == REG_EQUAL
3375 && DF_REG_DEF_COUNT (regno) != 1)
3376 note = NULL_RTX;
3378 if (note != NULL_RTX
3379 && GET_CODE (XEXP (note, 0)) != EXPR_LIST
3380 && ! rtx_varies_p (XEXP (note, 0), 1)
3381 && ! reg_overlap_mentioned_p (SET_DEST (set),
3382 XEXP (note, 0)))
3384 set_reg_known_value (regno, XEXP (note, 0));
3385 set_reg_known_equiv_p (regno,
3386 REG_NOTE_KIND (note) == REG_EQUIV);
3388 else if (DF_REG_DEF_COUNT (regno) == 1
3389 && GET_CODE (src) == PLUS
3390 && REG_P (XEXP (src, 0))
3391 && (t = get_reg_known_value (REGNO (XEXP (src, 0))))
3392 && CONST_INT_P (XEXP (src, 1)))
3394 t = plus_constant (GET_MODE (src), t,
3395 INTVAL (XEXP (src, 1)));
3396 set_reg_known_value (regno, t);
3397 set_reg_known_equiv_p (regno, false);
3399 else if (DF_REG_DEF_COUNT (regno) == 1
3400 && ! rtx_varies_p (src, 1))
3402 set_reg_known_value (regno, src);
3403 set_reg_known_equiv_p (regno, false);
3407 else if (NOTE_P (insn)
3408 && NOTE_KIND (insn) == NOTE_INSN_FUNCTION_BEG)
3409 copying_arguments = false;
3413 /* Now propagate values from new_reg_base_value to reg_base_value. */
3414 gcc_assert (maxreg == (unsigned int) max_reg_num ());
3416 for (ui = 0; ui < maxreg; ui++)
3418 if (new_reg_base_value[ui]
3419 && new_reg_base_value[ui] != (*reg_base_value)[ui]
3420 && ! rtx_equal_p (new_reg_base_value[ui], (*reg_base_value)[ui]))
3422 (*reg_base_value)[ui] = new_reg_base_value[ui];
3423 changed = 1;
3427 while (changed && ++pass < MAX_ALIAS_LOOP_PASSES);
3428 XDELETEVEC (rpo);
3430 /* Fill in the remaining entries. */
3431 FOR_EACH_VEC_ELT (*reg_known_value, i, val)
3433 int regno = i + FIRST_PSEUDO_REGISTER;
3434 if (! val)
3435 set_reg_known_value (regno, regno_reg_rtx[regno]);
3438 /* Clean up. */
3439 free (new_reg_base_value);
3440 new_reg_base_value = 0;
3441 sbitmap_free (reg_seen);
3442 reg_seen = 0;
3443 timevar_pop (TV_ALIAS_ANALYSIS);
3446 /* Equate REG_BASE_VALUE (reg1) to REG_BASE_VALUE (reg2).
3447 Special API for var-tracking pass purposes. */
3449 void
3450 vt_equate_reg_base_value (const_rtx reg1, const_rtx reg2)
3452 (*reg_base_value)[REGNO (reg1)] = REG_BASE_VALUE (reg2);
3455 void
3456 end_alias_analysis (void)
3458 old_reg_base_value = reg_base_value;
3459 vec_free (reg_known_value);
3460 sbitmap_free (reg_known_equiv_p);
3463 void
3464 dump_alias_stats_in_alias_c (FILE *s)
3466 fprintf (s, " TBAA oracle: %llu disambiguations %llu queries\n"
3467 " %llu are in alias set 0\n"
3468 " %llu queries asked about the same object\n"
3469 " %llu queries asked about the same alias set\n"
3470 " %llu access volatile\n"
3471 " %llu are dependent in the DAG\n"
3472 " %llu are aritificially in conflict with void *\n",
3473 alias_stats.num_disambiguated,
3474 alias_stats.num_alias_zero + alias_stats.num_same_alias_set
3475 + alias_stats.num_same_objects + alias_stats.num_volatile
3476 + alias_stats.num_dag + alias_stats.num_disambiguated
3477 + alias_stats.num_universal,
3478 alias_stats.num_alias_zero, alias_stats.num_same_alias_set,
3479 alias_stats.num_same_objects, alias_stats.num_volatile,
3480 alias_stats.num_dag, alias_stats.num_universal);
3482 #include "gt-alias.h"