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9ae8ffe7 1/* Alias analysis for GNU C
62e5bf5d 2 Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006,
c75c517d 3 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
9ae8ffe7
JL
4 Contributed by John Carr (jfc@mit.edu).
5
1322177d 6This file is part of GCC.
9ae8ffe7 7
1322177d
LB
8GCC is free software; you can redistribute it and/or modify it under
9the terms of the GNU General Public License as published by the Free
9dcd6f09 10Software Foundation; either version 3, or (at your option) any later
1322177d 11version.
9ae8ffe7 12
1322177d
LB
13GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14WARRANTY; without even the implied warranty of MERCHANTABILITY or
15FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16for more details.
9ae8ffe7
JL
17
18You should have received a copy of the GNU General Public License
9dcd6f09
NC
19along with GCC; see the file COPYING3. If not see
20<http://www.gnu.org/licenses/>. */
9ae8ffe7
JL
21
22#include "config.h"
670ee920 23#include "system.h"
4977bab6
ZW
24#include "coretypes.h"
25#include "tm.h"
9ae8ffe7 26#include "rtl.h"
7790df19 27#include "tree.h"
6baf1cc8 28#include "tm_p.h"
49ad7cfa 29#include "function.h"
78528714
JQ
30#include "alias.h"
31#include "emit-rtl.h"
9ae8ffe7
JL
32#include "regs.h"
33#include "hard-reg-set.h"
e004f2f7 34#include "basic-block.h"
9ae8ffe7 35#include "flags.h"
264fac34 36#include "output.h"
718f9c0f 37#include "diagnostic-core.h"
2e107e9e 38#include "toplev.h"
eab5c70a 39#include "cselib.h"
3932261a 40#include "splay-tree.h"
ac606739 41#include "ggc.h"
d23c55c2 42#include "langhooks.h"
0d446150 43#include "timevar.h"
ab780373 44#include "target.h"
b255a036 45#include "cgraph.h"
ef330312 46#include "tree-pass.h"
ea900239 47#include "ipa-type-escape.h"
6fb5fa3c 48#include "df.h"
55b34b5f
RG
49#include "tree-ssa-alias.h"
50#include "pointer-set.h"
51#include "tree-flow.h"
ea900239
DB
52
53/* The aliasing API provided here solves related but different problems:
54
c22cacf3 55 Say there exists (in c)
ea900239
DB
56
57 struct X {
58 struct Y y1;
59 struct Z z2;
60 } x1, *px1, *px2;
61
62 struct Y y2, *py;
63 struct Z z2, *pz;
64
65
66 py = &px1.y1;
67 px2 = &x1;
68
69 Consider the four questions:
70
71 Can a store to x1 interfere with px2->y1?
72 Can a store to x1 interfere with px2->z2?
73 (*px2).z2
74 Can a store to x1 change the value pointed to by with py?
75 Can a store to x1 change the value pointed to by with pz?
76
77 The answer to these questions can be yes, yes, yes, and maybe.
78
79 The first two questions can be answered with a simple examination
80 of the type system. If structure X contains a field of type Y then
81 a store thru a pointer to an X can overwrite any field that is
82 contained (recursively) in an X (unless we know that px1 != px2).
83
84 The last two of the questions can be solved in the same way as the
85 first two questions but this is too conservative. The observation
86 is that in some cases analysis we can know if which (if any) fields
87 are addressed and if those addresses are used in bad ways. This
88 analysis may be language specific. In C, arbitrary operations may
89 be applied to pointers. However, there is some indication that
90 this may be too conservative for some C++ types.
91
92 The pass ipa-type-escape does this analysis for the types whose
c22cacf3 93 instances do not escape across the compilation boundary.
ea900239
DB
94
95 Historically in GCC, these two problems were combined and a single
96 data structure was used to represent the solution to these
97 problems. We now have two similar but different data structures,
98 The data structure to solve the last two question is similar to the
99 first, but does not contain have the fields in it whose address are
100 never taken. For types that do escape the compilation unit, the
101 data structures will have identical information.
102*/
3932261a
MM
103
104/* The alias sets assigned to MEMs assist the back-end in determining
105 which MEMs can alias which other MEMs. In general, two MEMs in
ac3d9668
RK
106 different alias sets cannot alias each other, with one important
107 exception. Consider something like:
3932261a 108
01d28c3f 109 struct S { int i; double d; };
3932261a
MM
110
111 a store to an `S' can alias something of either type `int' or type
112 `double'. (However, a store to an `int' cannot alias a `double'
113 and vice versa.) We indicate this via a tree structure that looks
114 like:
c22cacf3
MS
115 struct S
116 / \
3932261a 117 / \
c22cacf3
MS
118 |/_ _\|
119 int double
3932261a 120
ac3d9668
RK
121 (The arrows are directed and point downwards.)
122 In this situation we say the alias set for `struct S' is the
123 `superset' and that those for `int' and `double' are `subsets'.
124
3bdf5ad1
RK
125 To see whether two alias sets can point to the same memory, we must
126 see if either alias set is a subset of the other. We need not trace
95bd1dd7 127 past immediate descendants, however, since we propagate all
3bdf5ad1 128 grandchildren up one level.
3932261a
MM
129
130 Alias set zero is implicitly a superset of all other alias sets.
131 However, this is no actual entry for alias set zero. It is an
132 error to attempt to explicitly construct a subset of zero. */
133
7e5487a2 134struct GTY(()) alias_set_entry_d {
3932261a 135 /* The alias set number, as stored in MEM_ALIAS_SET. */
4862826d 136 alias_set_type alias_set;
3932261a 137
4c067742
RG
138 /* Nonzero if would have a child of zero: this effectively makes this
139 alias set the same as alias set zero. */
140 int has_zero_child;
141
3932261a 142 /* The children of the alias set. These are not just the immediate
95bd1dd7 143 children, but, in fact, all descendants. So, if we have:
3932261a 144
ca7fd9cd 145 struct T { struct S s; float f; }
3932261a
MM
146
147 continuing our example above, the children here will be all of
148 `int', `double', `float', and `struct S'. */
b604074c 149 splay_tree GTY((param1_is (int), param2_is (int))) children;
b604074c 150};
7e5487a2 151typedef struct alias_set_entry_d *alias_set_entry;
9ae8ffe7 152
ed7a4b4b 153static int rtx_equal_for_memref_p (const_rtx, const_rtx);
4682ae04 154static int memrefs_conflict_p (int, rtx, int, rtx, HOST_WIDE_INT);
7bc980e1 155static void record_set (rtx, const_rtx, void *);
4682ae04
AJ
156static int base_alias_check (rtx, rtx, enum machine_mode,
157 enum machine_mode);
158static rtx find_base_value (rtx);
4f588890 159static int mems_in_disjoint_alias_sets_p (const_rtx, const_rtx);
4682ae04 160static int insert_subset_children (splay_tree_node, void*);
4862826d 161static alias_set_entry get_alias_set_entry (alias_set_type);
4f588890
KG
162static const_rtx fixed_scalar_and_varying_struct_p (const_rtx, const_rtx, rtx, rtx,
163 bool (*) (const_rtx, bool));
164static int aliases_everything_p (const_rtx);
165static bool nonoverlapping_component_refs_p (const_tree, const_tree);
4682ae04
AJ
166static tree decl_for_component_ref (tree);
167static rtx adjust_offset_for_component_ref (tree, rtx);
4f588890 168static int write_dependence_p (const_rtx, const_rtx, int);
4682ae04 169
aa317c97 170static void memory_modified_1 (rtx, const_rtx, void *);
9ae8ffe7
JL
171
172/* Set up all info needed to perform alias analysis on memory references. */
173
d4b60170 174/* Returns the size in bytes of the mode of X. */
9ae8ffe7
JL
175#define SIZE_FOR_MODE(X) (GET_MODE_SIZE (GET_MODE (X)))
176
41472af8 177/* Returns nonzero if MEM1 and MEM2 do not alias because they are in
264fac34
MM
178 different alias sets. We ignore alias sets in functions making use
179 of variable arguments because the va_arg macros on some systems are
180 not legal ANSI C. */
181#define DIFFERENT_ALIAS_SETS_P(MEM1, MEM2) \
3932261a 182 mems_in_disjoint_alias_sets_p (MEM1, MEM2)
41472af8 183
ea64ef27 184/* Cap the number of passes we make over the insns propagating alias
ac3d9668 185 information through set chains. 10 is a completely arbitrary choice. */
ea64ef27 186#define MAX_ALIAS_LOOP_PASSES 10
ca7fd9cd 187
9ae8ffe7
JL
188/* reg_base_value[N] gives an address to which register N is related.
189 If all sets after the first add or subtract to the current value
190 or otherwise modify it so it does not point to a different top level
191 object, reg_base_value[N] is equal to the address part of the source
2a2c8203
JC
192 of the first set.
193
194 A base address can be an ADDRESS, SYMBOL_REF, or LABEL_REF. ADDRESS
195 expressions represent certain special values: function arguments and
ca7fd9cd 196 the stack, frame, and argument pointers.
b3b5ad95
JL
197
198 The contents of an ADDRESS is not normally used, the mode of the
199 ADDRESS determines whether the ADDRESS is a function argument or some
200 other special value. Pointer equality, not rtx_equal_p, determines whether
201 two ADDRESS expressions refer to the same base address.
202
203 The only use of the contents of an ADDRESS is for determining if the
204 current function performs nonlocal memory memory references for the
205 purposes of marking the function as a constant function. */
2a2c8203 206
08c79682 207static GTY(()) VEC(rtx,gc) *reg_base_value;
ac606739 208static rtx *new_reg_base_value;
c582d54a
JH
209
210/* We preserve the copy of old array around to avoid amount of garbage
211 produced. About 8% of garbage produced were attributed to this
212 array. */
08c79682 213static GTY((deletable)) VEC(rtx,gc) *old_reg_base_value;
d4b60170 214
7bf84454
RS
215#define static_reg_base_value \
216 (this_target_rtl->x_static_reg_base_value)
bf1660a6 217
08c79682
KH
218#define REG_BASE_VALUE(X) \
219 (REGNO (X) < VEC_length (rtx, reg_base_value) \
220 ? VEC_index (rtx, reg_base_value, REGNO (X)) : 0)
9ae8ffe7 221
c13e8210 222/* Vector indexed by N giving the initial (unchanging) value known for
bb1acb3e
RH
223 pseudo-register N. This array is initialized in init_alias_analysis,
224 and does not change until end_alias_analysis is called. */
225static GTY((length("reg_known_value_size"))) rtx *reg_known_value;
9ae8ffe7
JL
226
227/* Indicates number of valid entries in reg_known_value. */
bb1acb3e 228static GTY(()) unsigned int reg_known_value_size;
9ae8ffe7
JL
229
230/* Vector recording for each reg_known_value whether it is due to a
231 REG_EQUIV note. Future passes (viz., reload) may replace the
232 pseudo with the equivalent expression and so we account for the
ac3d9668
RK
233 dependences that would be introduced if that happens.
234
235 The REG_EQUIV notes created in assign_parms may mention the arg
236 pointer, and there are explicit insns in the RTL that modify the
237 arg pointer. Thus we must ensure that such insns don't get
238 scheduled across each other because that would invalidate the
239 REG_EQUIV notes. One could argue that the REG_EQUIV notes are
240 wrong, but solving the problem in the scheduler will likely give
241 better code, so we do it here. */
bb1acb3e 242static bool *reg_known_equiv_p;
9ae8ffe7 243
2a2c8203
JC
244/* True when scanning insns from the start of the rtl to the
245 NOTE_INSN_FUNCTION_BEG note. */
83bbd9b6 246static bool copying_arguments;
9ae8ffe7 247
1a5640b4
KH
248DEF_VEC_P(alias_set_entry);
249DEF_VEC_ALLOC_P(alias_set_entry,gc);
250
3932261a 251/* The splay-tree used to store the various alias set entries. */
1a5640b4 252static GTY (()) VEC(alias_set_entry,gc) *alias_sets;
ac3d9668 253\f
55b34b5f
RG
254/* Build a decomposed reference object for querying the alias-oracle
255 from the MEM rtx and store it in *REF.
256 Returns false if MEM is not suitable for the alias-oracle. */
257
258static bool
259ao_ref_from_mem (ao_ref *ref, const_rtx mem)
260{
261 tree expr = MEM_EXPR (mem);
262 tree base;
263
264 if (!expr)
265 return false;
266
267 ao_ref_init (ref, expr);
268
269 /* Get the base of the reference and see if we have to reject or
270 adjust it. */
271 base = ao_ref_base (ref);
272 if (base == NULL_TREE)
273 return false;
274
366f945f
RG
275 /* The tree oracle doesn't like to have these. */
276 if (TREE_CODE (base) == FUNCTION_DECL
277 || TREE_CODE (base) == LABEL_DECL)
278 return false;
279
55b34b5f
RG
280 /* If this is a pointer dereference of a non-SSA_NAME punt.
281 ??? We could replace it with a pointer to anything. */
70f34814
RG
282 if ((INDIRECT_REF_P (base)
283 || TREE_CODE (base) == MEM_REF)
55b34b5f
RG
284 && TREE_CODE (TREE_OPERAND (base, 0)) != SSA_NAME)
285 return false;
286
287 /* If this is a reference based on a partitioned decl replace the
288 base with an INDIRECT_REF of the pointer representative we
289 created during stack slot partitioning. */
290 if (TREE_CODE (base) == VAR_DECL
291 && ! TREE_STATIC (base)
292 && cfun->gimple_df->decls_to_pointers != NULL)
293 {
294 void *namep;
295 namep = pointer_map_contains (cfun->gimple_df->decls_to_pointers, base);
296 if (namep)
70f34814 297 ref->base = build_simple_mem_ref (*(tree *)namep);
55b34b5f
RG
298 }
299
300 ref->ref_alias_set = MEM_ALIAS_SET (mem);
301
366f945f
RG
302 /* If MEM_OFFSET or MEM_SIZE are NULL we have to punt.
303 Keep points-to related information though. */
304 if (!MEM_OFFSET (mem)
305 || !MEM_SIZE (mem))
306 {
307 ref->ref = NULL_TREE;
308 ref->offset = 0;
309 ref->size = -1;
310 ref->max_size = -1;
311 return true;
312 }
313
b0e96404
RG
314 /* If the base decl is a parameter we can have negative MEM_OFFSET in
315 case of promoted subregs on bigendian targets. Trust the MEM_EXPR
316 here. */
317 if (INTVAL (MEM_OFFSET (mem)) < 0
318 && ((INTVAL (MEM_SIZE (mem)) + INTVAL (MEM_OFFSET (mem)))
319 * BITS_PER_UNIT) == ref->size)
320 return true;
321
322 ref->offset += INTVAL (MEM_OFFSET (mem)) * BITS_PER_UNIT;
323 ref->size = INTVAL (MEM_SIZE (mem)) * BITS_PER_UNIT;
324
325 /* The MEM may extend into adjacent fields, so adjust max_size if
326 necessary. */
327 if (ref->max_size != -1
328 && ref->size > ref->max_size)
329 ref->max_size = ref->size;
330
331 /* If MEM_OFFSET and MEM_SIZE get us outside of the base object of
332 the MEM_EXPR punt. This happens for STRICT_ALIGNMENT targets a lot. */
333 if (MEM_EXPR (mem) != get_spill_slot_decl (false)
334 && (ref->offset < 0
335 || (DECL_P (ref->base)
336 && (!host_integerp (DECL_SIZE (ref->base), 1)
337 || (TREE_INT_CST_LOW (DECL_SIZE ((ref->base)))
338 < (unsigned HOST_WIDE_INT)(ref->offset + ref->size))))))
339 return false;
55b34b5f
RG
340
341 return true;
342}
343
344/* Query the alias-oracle on whether the two memory rtx X and MEM may
345 alias. If TBAA_P is set also apply TBAA. Returns true if the
346 two rtxen may alias, false otherwise. */
347
348static bool
349rtx_refs_may_alias_p (const_rtx x, const_rtx mem, bool tbaa_p)
350{
351 ao_ref ref1, ref2;
352
353 if (!ao_ref_from_mem (&ref1, x)
354 || !ao_ref_from_mem (&ref2, mem))
355 return true;
356
357 return refs_may_alias_p_1 (&ref1, &ref2, tbaa_p);
358}
359
3932261a
MM
360/* Returns a pointer to the alias set entry for ALIAS_SET, if there is
361 such an entry, or NULL otherwise. */
362
9ddb66ca 363static inline alias_set_entry
4862826d 364get_alias_set_entry (alias_set_type alias_set)
3932261a 365{
1a5640b4 366 return VEC_index (alias_set_entry, alias_sets, alias_set);
3932261a
MM
367}
368
ac3d9668
RK
369/* Returns nonzero if the alias sets for MEM1 and MEM2 are such that
370 the two MEMs cannot alias each other. */
3932261a 371
9ddb66ca 372static inline int
4f588890 373mems_in_disjoint_alias_sets_p (const_rtx mem1, const_rtx mem2)
3932261a 374{
3932261a
MM
375/* Perform a basic sanity check. Namely, that there are no alias sets
376 if we're not using strict aliasing. This helps to catch bugs
377 whereby someone uses PUT_CODE, but doesn't clear MEM_ALIAS_SET, or
378 where a MEM is allocated in some way other than by the use of
379 gen_rtx_MEM, and the MEM_ALIAS_SET is not cleared. If we begin to
380 use alias sets to indicate that spilled registers cannot alias each
381 other, we might need to remove this check. */
298e6adc
NS
382 gcc_assert (flag_strict_aliasing
383 || (!MEM_ALIAS_SET (mem1) && !MEM_ALIAS_SET (mem2)));
3932261a 384
1da68f56
RK
385 return ! alias_sets_conflict_p (MEM_ALIAS_SET (mem1), MEM_ALIAS_SET (mem2));
386}
3932261a 387
1da68f56
RK
388/* Insert the NODE into the splay tree given by DATA. Used by
389 record_alias_subset via splay_tree_foreach. */
390
391static int
4682ae04 392insert_subset_children (splay_tree_node node, void *data)
1da68f56
RK
393{
394 splay_tree_insert ((splay_tree) data, node->key, node->value);
395
396 return 0;
397}
398
c58936b6
DB
399/* Return true if the first alias set is a subset of the second. */
400
401bool
4862826d 402alias_set_subset_of (alias_set_type set1, alias_set_type set2)
c58936b6
DB
403{
404 alias_set_entry ase;
405
406 /* Everything is a subset of the "aliases everything" set. */
407 if (set2 == 0)
408 return true;
409
410 /* Otherwise, check if set1 is a subset of set2. */
411 ase = get_alias_set_entry (set2);
412 if (ase != 0
038a39d1 413 && (ase->has_zero_child
a7a512be
RG
414 || splay_tree_lookup (ase->children,
415 (splay_tree_key) set1)))
c58936b6
DB
416 return true;
417 return false;
418}
419
1da68f56
RK
420/* Return 1 if the two specified alias sets may conflict. */
421
422int
4862826d 423alias_sets_conflict_p (alias_set_type set1, alias_set_type set2)
1da68f56
RK
424{
425 alias_set_entry ase;
426
836f7794
EB
427 /* The easy case. */
428 if (alias_sets_must_conflict_p (set1, set2))
1da68f56 429 return 1;
3932261a 430
3bdf5ad1 431 /* See if the first alias set is a subset of the second. */
1da68f56 432 ase = get_alias_set_entry (set1);
2bf105ab
RK
433 if (ase != 0
434 && (ase->has_zero_child
435 || splay_tree_lookup (ase->children,
1da68f56
RK
436 (splay_tree_key) set2)))
437 return 1;
3932261a
MM
438
439 /* Now do the same, but with the alias sets reversed. */
1da68f56 440 ase = get_alias_set_entry (set2);
2bf105ab
RK
441 if (ase != 0
442 && (ase->has_zero_child
443 || splay_tree_lookup (ase->children,
1da68f56
RK
444 (splay_tree_key) set1)))
445 return 1;
3932261a 446
1da68f56 447 /* The two alias sets are distinct and neither one is the
836f7794 448 child of the other. Therefore, they cannot conflict. */
1da68f56 449 return 0;
3932261a 450}
5399d643 451
71a6fe66
BM
452static int
453walk_mems_2 (rtx *x, rtx mem)
454{
455 if (MEM_P (*x))
456 {
457 if (alias_sets_conflict_p (MEM_ALIAS_SET(*x), MEM_ALIAS_SET(mem)))
458 return 1;
b8698a0f
L
459
460 return -1;
71a6fe66
BM
461 }
462 return 0;
463}
464
465static int
466walk_mems_1 (rtx *x, rtx *pat)
467{
468 if (MEM_P (*x))
469 {
470 /* Visit all MEMs in *PAT and check indepedence. */
471 if (for_each_rtx (pat, (rtx_function) walk_mems_2, *x))
472 /* Indicate that dependence was determined and stop traversal. */
473 return 1;
b8698a0f 474
71a6fe66
BM
475 return -1;
476 }
477 return 0;
478}
479
480/* Return 1 if two specified instructions have mem expr with conflict alias sets*/
481bool
482insn_alias_sets_conflict_p (rtx insn1, rtx insn2)
483{
484 /* For each pair of MEMs in INSN1 and INSN2 check their independence. */
485 return for_each_rtx (&PATTERN (insn1), (rtx_function) walk_mems_1,
486 &PATTERN (insn2));
487}
488
836f7794 489/* Return 1 if the two specified alias sets will always conflict. */
5399d643
JW
490
491int
4862826d 492alias_sets_must_conflict_p (alias_set_type set1, alias_set_type set2)
5399d643
JW
493{
494 if (set1 == 0 || set2 == 0 || set1 == set2)
495 return 1;
496
497 return 0;
498}
499
1da68f56
RK
500/* Return 1 if any MEM object of type T1 will always conflict (using the
501 dependency routines in this file) with any MEM object of type T2.
502 This is used when allocating temporary storage. If T1 and/or T2 are
503 NULL_TREE, it means we know nothing about the storage. */
504
505int
4682ae04 506objects_must_conflict_p (tree t1, tree t2)
1da68f56 507{
4862826d 508 alias_set_type set1, set2;
82d610ec 509
e8ea2809
RK
510 /* If neither has a type specified, we don't know if they'll conflict
511 because we may be using them to store objects of various types, for
512 example the argument and local variables areas of inlined functions. */
981a4c34 513 if (t1 == 0 && t2 == 0)
e8ea2809
RK
514 return 0;
515
1da68f56
RK
516 /* If they are the same type, they must conflict. */
517 if (t1 == t2
518 /* Likewise if both are volatile. */
519 || (t1 != 0 && TYPE_VOLATILE (t1) && t2 != 0 && TYPE_VOLATILE (t2)))
520 return 1;
521
82d610ec
RK
522 set1 = t1 ? get_alias_set (t1) : 0;
523 set2 = t2 ? get_alias_set (t2) : 0;
1da68f56 524
836f7794
EB
525 /* We can't use alias_sets_conflict_p because we must make sure
526 that every subtype of t1 will conflict with every subtype of
82d610ec
RK
527 t2 for which a pair of subobjects of these respective subtypes
528 overlaps on the stack. */
836f7794 529 return alias_sets_must_conflict_p (set1, set2);
1da68f56
RK
530}
531\f
2039d7aa
RH
532/* Return true if all nested component references handled by
533 get_inner_reference in T are such that we should use the alias set
534 provided by the object at the heart of T.
535
536 This is true for non-addressable components (which don't have their
537 own alias set), as well as components of objects in alias set zero.
538 This later point is a special case wherein we wish to override the
539 alias set used by the component, but we don't have per-FIELD_DECL
540 assignable alias sets. */
541
542bool
22ea9ec0 543component_uses_parent_alias_set (const_tree t)
6e24b709 544{
afe84921
RH
545 while (1)
546 {
2039d7aa 547 /* If we're at the end, it vacuously uses its own alias set. */
afe84921 548 if (!handled_component_p (t))
2039d7aa 549 return false;
afe84921
RH
550
551 switch (TREE_CODE (t))
552 {
553 case COMPONENT_REF:
554 if (DECL_NONADDRESSABLE_P (TREE_OPERAND (t, 1)))
2039d7aa 555 return true;
afe84921
RH
556 break;
557
558 case ARRAY_REF:
559 case ARRAY_RANGE_REF:
560 if (TYPE_NONALIASED_COMPONENT (TREE_TYPE (TREE_OPERAND (t, 0))))
2039d7aa 561 return true;
afe84921
RH
562 break;
563
564 case REALPART_EXPR:
565 case IMAGPART_EXPR:
566 break;
567
568 default:
569 /* Bitfields and casts are never addressable. */
2039d7aa 570 return true;
afe84921
RH
571 }
572
573 t = TREE_OPERAND (t, 0);
2039d7aa
RH
574 if (get_alias_set (TREE_TYPE (t)) == 0)
575 return true;
afe84921 576 }
6e24b709
RK
577}
578
5006671f
RG
579/* Return the alias set for the memory pointed to by T, which may be
580 either a type or an expression. Return -1 if there is nothing
581 special about dereferencing T. */
582
583static alias_set_type
584get_deref_alias_set_1 (tree t)
585{
586 /* If we're not doing any alias analysis, just assume everything
587 aliases everything else. */
588 if (!flag_strict_aliasing)
589 return 0;
590
5b21f0f3 591 /* All we care about is the type. */
5006671f 592 if (! TYPE_P (t))
5b21f0f3 593 t = TREE_TYPE (t);
5006671f
RG
594
595 /* If we have an INDIRECT_REF via a void pointer, we don't
596 know anything about what that might alias. Likewise if the
597 pointer is marked that way. */
598 if (TREE_CODE (TREE_TYPE (t)) == VOID_TYPE
599 || TYPE_REF_CAN_ALIAS_ALL (t))
600 return 0;
601
602 return -1;
603}
604
605/* Return the alias set for the memory pointed to by T, which may be
606 either a type or an expression. */
607
608alias_set_type
609get_deref_alias_set (tree t)
610{
611 alias_set_type set = get_deref_alias_set_1 (t);
612
613 /* Fall back to the alias-set of the pointed-to type. */
614 if (set == -1)
615 {
616 if (! TYPE_P (t))
617 t = TREE_TYPE (t);
618 set = get_alias_set (TREE_TYPE (t));
619 }
620
621 return set;
622}
623
3bdf5ad1
RK
624/* Return the alias set for T, which may be either a type or an
625 expression. Call language-specific routine for help, if needed. */
626
4862826d 627alias_set_type
4682ae04 628get_alias_set (tree t)
3bdf5ad1 629{
4862826d 630 alias_set_type set;
3bdf5ad1
RK
631
632 /* If we're not doing any alias analysis, just assume everything
633 aliases everything else. Also return 0 if this or its type is
634 an error. */
635 if (! flag_strict_aliasing || t == error_mark_node
636 || (! TYPE_P (t)
637 && (TREE_TYPE (t) == 0 || TREE_TYPE (t) == error_mark_node)))
638 return 0;
639
640 /* We can be passed either an expression or a type. This and the
f47e9b4e
RK
641 language-specific routine may make mutually-recursive calls to each other
642 to figure out what to do. At each juncture, we see if this is a tree
643 that the language may need to handle specially. First handle things that
738cc472 644 aren't types. */
f824e5c3 645 if (! TYPE_P (t))
3bdf5ad1 646 {
ebcc3d93 647 tree inner;
738cc472 648
70f34814
RG
649 /* Give the language a chance to do something with this tree
650 before we look at it. */
8ac61af7 651 STRIP_NOPS (t);
ae2bcd98 652 set = lang_hooks.get_alias_set (t);
8ac61af7
RK
653 if (set != -1)
654 return set;
655
ebcc3d93
EB
656 /* Retrieve the original memory reference if needed. */
657 if (TREE_CODE (t) == TARGET_MEM_REF)
658 t = TMR_ORIGINAL (t);
659
70f34814 660 /* Get the base object of the reference. */
ebcc3d93 661 inner = t;
6fce44af 662 while (handled_component_p (inner))
738cc472 663 {
70f34814
RG
664 /* If there is a VIEW_CONVERT_EXPR in the chain we cannot use
665 the type of any component references that wrap it to
666 determine the alias-set. */
667 if (TREE_CODE (inner) == VIEW_CONVERT_EXPR)
668 t = TREE_OPERAND (inner, 0);
6fce44af 669 inner = TREE_OPERAND (inner, 0);
738cc472
RK
670 }
671
70f34814
RG
672 /* Handle pointer dereferences here, they can override the
673 alias-set. */
1b096a0a 674 if (INDIRECT_REF_P (inner))
738cc472 675 {
5006671f
RG
676 set = get_deref_alias_set_1 (TREE_OPERAND (inner, 0));
677 if (set != -1)
678 return set;
738cc472 679 }
70f34814
RG
680 else if (TREE_CODE (inner) == MEM_REF)
681 {
682 set = get_deref_alias_set_1 (TREE_OPERAND (inner, 1));
683 if (set != -1)
684 return set;
685 }
686
687 /* If the innermost reference is a MEM_REF that has a
688 conversion embedded treat it like a VIEW_CONVERT_EXPR above,
689 using the memory access type for determining the alias-set. */
690 if (TREE_CODE (inner) == MEM_REF
691 && (TYPE_MAIN_VARIANT (TREE_TYPE (inner))
692 != TYPE_MAIN_VARIANT
693 (TREE_TYPE (TREE_TYPE (TREE_OPERAND (inner, 1))))))
694 return get_deref_alias_set (TREE_OPERAND (inner, 1));
738cc472
RK
695
696 /* Otherwise, pick up the outermost object that we could have a pointer
6fce44af 697 to, processing conversions as above. */
2039d7aa 698 while (component_uses_parent_alias_set (t))
f47e9b4e 699 {
6fce44af 700 t = TREE_OPERAND (t, 0);
8ac61af7
RK
701 STRIP_NOPS (t);
702 }
f824e5c3 703
738cc472
RK
704 /* If we've already determined the alias set for a decl, just return
705 it. This is necessary for C++ anonymous unions, whose component
706 variables don't look like union members (boo!). */
5755cd38 707 if (TREE_CODE (t) == VAR_DECL
3c0cb5de 708 && DECL_RTL_SET_P (t) && MEM_P (DECL_RTL (t)))
5755cd38
JM
709 return MEM_ALIAS_SET (DECL_RTL (t));
710
f824e5c3
RK
711 /* Now all we care about is the type. */
712 t = TREE_TYPE (t);
3bdf5ad1
RK
713 }
714
3bdf5ad1 715 /* Variant qualifiers don't affect the alias set, so get the main
daad0278 716 variant. */
3bdf5ad1 717 t = TYPE_MAIN_VARIANT (t);
daad0278
RG
718
719 /* Always use the canonical type as well. If this is a type that
720 requires structural comparisons to identify compatible types
721 use alias set zero. */
722 if (TYPE_STRUCTURAL_EQUALITY_P (t))
cb9c2485
JM
723 {
724 /* Allow the language to specify another alias set for this
725 type. */
726 set = lang_hooks.get_alias_set (t);
727 if (set != -1)
728 return set;
729 return 0;
730 }
daad0278
RG
731 t = TYPE_CANONICAL (t);
732 /* Canonical types shouldn't form a tree nor should the canonical
733 type require structural equality checks. */
7a40b8b1 734 gcc_checking_assert (!TYPE_STRUCTURAL_EQUALITY_P (t) && TYPE_CANONICAL (t) == t);
daad0278
RG
735
736 /* If this is a type with a known alias set, return it. */
738cc472 737 if (TYPE_ALIAS_SET_KNOWN_P (t))
3bdf5ad1
RK
738 return TYPE_ALIAS_SET (t);
739
36784d0e
RG
740 /* We don't want to set TYPE_ALIAS_SET for incomplete types. */
741 if (!COMPLETE_TYPE_P (t))
742 {
743 /* For arrays with unknown size the conservative answer is the
744 alias set of the element type. */
745 if (TREE_CODE (t) == ARRAY_TYPE)
746 return get_alias_set (TREE_TYPE (t));
747
748 /* But return zero as a conservative answer for incomplete types. */
749 return 0;
750 }
751
3bdf5ad1 752 /* See if the language has special handling for this type. */
ae2bcd98 753 set = lang_hooks.get_alias_set (t);
8ac61af7 754 if (set != -1)
738cc472 755 return set;
2bf105ab 756
3bdf5ad1
RK
757 /* There are no objects of FUNCTION_TYPE, so there's no point in
758 using up an alias set for them. (There are, of course, pointers
759 and references to functions, but that's different.) */
e11e491d
RG
760 else if (TREE_CODE (t) == FUNCTION_TYPE
761 || TREE_CODE (t) == METHOD_TYPE)
3bdf5ad1 762 set = 0;
74d86f4f
RH
763
764 /* Unless the language specifies otherwise, let vector types alias
765 their components. This avoids some nasty type punning issues in
766 normal usage. And indeed lets vectors be treated more like an
767 array slice. */
768 else if (TREE_CODE (t) == VECTOR_TYPE)
769 set = get_alias_set (TREE_TYPE (t));
770
4653cae5
RG
771 /* Unless the language specifies otherwise, treat array types the
772 same as their components. This avoids the asymmetry we get
773 through recording the components. Consider accessing a
774 character(kind=1) through a reference to a character(kind=1)[1:1].
775 Or consider if we want to assign integer(kind=4)[0:D.1387] and
776 integer(kind=4)[4] the same alias set or not.
777 Just be pragmatic here and make sure the array and its element
778 type get the same alias set assigned. */
779 else if (TREE_CODE (t) == ARRAY_TYPE
780 && !TYPE_NONALIASED_COMPONENT (t))
781 set = get_alias_set (TREE_TYPE (t));
782
3bdf5ad1
RK
783 else
784 /* Otherwise make a new alias set for this type. */
785 set = new_alias_set ();
786
787 TYPE_ALIAS_SET (t) = set;
2bf105ab
RK
788
789 /* If this is an aggregate type, we must record any component aliasing
790 information. */
1d79fd2c 791 if (AGGREGATE_TYPE_P (t) || TREE_CODE (t) == COMPLEX_TYPE)
2bf105ab
RK
792 record_component_aliases (t);
793
3bdf5ad1
RK
794 return set;
795}
796
797/* Return a brand-new alias set. */
798
4862826d 799alias_set_type
4682ae04 800new_alias_set (void)
3bdf5ad1 801{
3bdf5ad1 802 if (flag_strict_aliasing)
9ddb66ca 803 {
1a5640b4
KH
804 if (alias_sets == 0)
805 VEC_safe_push (alias_set_entry, gc, alias_sets, 0);
806 VEC_safe_push (alias_set_entry, gc, alias_sets, 0);
807 return VEC_length (alias_set_entry, alias_sets) - 1;
9ddb66ca 808 }
3bdf5ad1
RK
809 else
810 return 0;
811}
3932261a 812
01d28c3f
JM
813/* Indicate that things in SUBSET can alias things in SUPERSET, but that
814 not everything that aliases SUPERSET also aliases SUBSET. For example,
815 in C, a store to an `int' can alias a load of a structure containing an
816 `int', and vice versa. But it can't alias a load of a 'double' member
817 of the same structure. Here, the structure would be the SUPERSET and
818 `int' the SUBSET. This relationship is also described in the comment at
819 the beginning of this file.
820
821 This function should be called only once per SUPERSET/SUBSET pair.
3932261a
MM
822
823 It is illegal for SUPERSET to be zero; everything is implicitly a
824 subset of alias set zero. */
825
794511d2 826void
4862826d 827record_alias_subset (alias_set_type superset, alias_set_type subset)
3932261a
MM
828{
829 alias_set_entry superset_entry;
830 alias_set_entry subset_entry;
831
f47e9b4e
RK
832 /* It is possible in complex type situations for both sets to be the same,
833 in which case we can ignore this operation. */
834 if (superset == subset)
835 return;
836
298e6adc 837 gcc_assert (superset);
3932261a
MM
838
839 superset_entry = get_alias_set_entry (superset);
ca7fd9cd 840 if (superset_entry == 0)
3932261a
MM
841 {
842 /* Create an entry for the SUPERSET, so that we have a place to
843 attach the SUBSET. */
a9429e29 844 superset_entry = ggc_alloc_cleared_alias_set_entry_d ();
3932261a 845 superset_entry->alias_set = superset;
ca7fd9cd 846 superset_entry->children
a9429e29
LB
847 = splay_tree_new_ggc (splay_tree_compare_ints,
848 ggc_alloc_splay_tree_scalar_scalar_splay_tree_s,
849 ggc_alloc_splay_tree_scalar_scalar_splay_tree_node_s);
570eb5c8 850 superset_entry->has_zero_child = 0;
1a5640b4 851 VEC_replace (alias_set_entry, alias_sets, superset, superset_entry);
3932261a
MM
852 }
853
2bf105ab
RK
854 if (subset == 0)
855 superset_entry->has_zero_child = 1;
856 else
857 {
858 subset_entry = get_alias_set_entry (subset);
859 /* If there is an entry for the subset, enter all of its children
860 (if they are not already present) as children of the SUPERSET. */
ca7fd9cd 861 if (subset_entry)
2bf105ab
RK
862 {
863 if (subset_entry->has_zero_child)
864 superset_entry->has_zero_child = 1;
d4b60170 865
2bf105ab
RK
866 splay_tree_foreach (subset_entry->children, insert_subset_children,
867 superset_entry->children);
868 }
3932261a 869
2bf105ab 870 /* Enter the SUBSET itself as a child of the SUPERSET. */
ca7fd9cd 871 splay_tree_insert (superset_entry->children,
2bf105ab
RK
872 (splay_tree_key) subset, 0);
873 }
3932261a
MM
874}
875
a0c33338
RK
876/* Record that component types of TYPE, if any, are part of that type for
877 aliasing purposes. For record types, we only record component types
b5487346
EB
878 for fields that are not marked non-addressable. For array types, we
879 only record the component type if it is not marked non-aliased. */
a0c33338
RK
880
881void
4682ae04 882record_component_aliases (tree type)
a0c33338 883{
4862826d 884 alias_set_type superset = get_alias_set (type);
a0c33338
RK
885 tree field;
886
887 if (superset == 0)
888 return;
889
890 switch (TREE_CODE (type))
891 {
a0c33338
RK
892 case RECORD_TYPE:
893 case UNION_TYPE:
894 case QUAL_UNION_TYPE:
6614fd40 895 /* Recursively record aliases for the base classes, if there are any. */
fa743e8c 896 if (TYPE_BINFO (type))
ca7fd9cd
KH
897 {
898 int i;
fa743e8c 899 tree binfo, base_binfo;
c22cacf3 900
fa743e8c
NS
901 for (binfo = TYPE_BINFO (type), i = 0;
902 BINFO_BASE_ITERATE (binfo, i, base_binfo); i++)
903 record_alias_subset (superset,
904 get_alias_set (BINFO_TYPE (base_binfo)));
ca7fd9cd 905 }
a0c33338 906 for (field = TYPE_FIELDS (type); field != 0; field = TREE_CHAIN (field))
b5487346 907 if (TREE_CODE (field) == FIELD_DECL && !DECL_NONADDRESSABLE_P (field))
2bf105ab 908 record_alias_subset (superset, get_alias_set (TREE_TYPE (field)));
a0c33338
RK
909 break;
910
1d79fd2c
JW
911 case COMPLEX_TYPE:
912 record_alias_subset (superset, get_alias_set (TREE_TYPE (type)));
913 break;
914
4653cae5
RG
915 /* VECTOR_TYPE and ARRAY_TYPE share the alias set with their
916 element type. */
917
a0c33338
RK
918 default:
919 break;
920 }
921}
922
3bdf5ad1
RK
923/* Allocate an alias set for use in storing and reading from the varargs
924 spill area. */
925
4862826d 926static GTY(()) alias_set_type varargs_set = -1;
f103e34d 927
4862826d 928alias_set_type
4682ae04 929get_varargs_alias_set (void)
3bdf5ad1 930{
cd3ce9b4
JM
931#if 1
932 /* We now lower VA_ARG_EXPR, and there's currently no way to attach the
933 varargs alias set to an INDIRECT_REF (FIXME!), so we can't
934 consistently use the varargs alias set for loads from the varargs
935 area. So don't use it anywhere. */
936 return 0;
937#else
f103e34d
GK
938 if (varargs_set == -1)
939 varargs_set = new_alias_set ();
3bdf5ad1 940
f103e34d 941 return varargs_set;
cd3ce9b4 942#endif
3bdf5ad1
RK
943}
944
945/* Likewise, but used for the fixed portions of the frame, e.g., register
946 save areas. */
947
4862826d 948static GTY(()) alias_set_type frame_set = -1;
f103e34d 949
4862826d 950alias_set_type
4682ae04 951get_frame_alias_set (void)
3bdf5ad1 952{
f103e34d
GK
953 if (frame_set == -1)
954 frame_set = new_alias_set ();
3bdf5ad1 955
f103e34d 956 return frame_set;
3bdf5ad1
RK
957}
958
2a2c8203
JC
959/* Inside SRC, the source of a SET, find a base address. */
960
9ae8ffe7 961static rtx
4682ae04 962find_base_value (rtx src)
9ae8ffe7 963{
713f41f9 964 unsigned int regno;
0aacc8ed 965
53451050
RS
966#if defined (FIND_BASE_TERM)
967 /* Try machine-dependent ways to find the base term. */
968 src = FIND_BASE_TERM (src);
969#endif
970
9ae8ffe7
JL
971 switch (GET_CODE (src))
972 {
973 case SYMBOL_REF:
974 case LABEL_REF:
975 return src;
976
977 case REG:
fb6754f0 978 regno = REGNO (src);
d4b60170 979 /* At the start of a function, argument registers have known base
2a2c8203
JC
980 values which may be lost later. Returning an ADDRESS
981 expression here allows optimization based on argument values
982 even when the argument registers are used for other purposes. */
713f41f9
BS
983 if (regno < FIRST_PSEUDO_REGISTER && copying_arguments)
984 return new_reg_base_value[regno];
73774bc7 985
eaf407a5 986 /* If a pseudo has a known base value, return it. Do not do this
9b462c42
RH
987 for non-fixed hard regs since it can result in a circular
988 dependency chain for registers which have values at function entry.
eaf407a5
JL
989
990 The test above is not sufficient because the scheduler may move
991 a copy out of an arg reg past the NOTE_INSN_FUNCTION_BEGIN. */
9b462c42 992 if ((regno >= FIRST_PSEUDO_REGISTER || fixed_regs[regno])
08c79682 993 && regno < VEC_length (rtx, reg_base_value))
83bbd9b6
RH
994 {
995 /* If we're inside init_alias_analysis, use new_reg_base_value
996 to reduce the number of relaxation iterations. */
1afdf91c 997 if (new_reg_base_value && new_reg_base_value[regno]
6fb5fa3c 998 && DF_REG_DEF_COUNT (regno) == 1)
83bbd9b6
RH
999 return new_reg_base_value[regno];
1000
08c79682
KH
1001 if (VEC_index (rtx, reg_base_value, regno))
1002 return VEC_index (rtx, reg_base_value, regno);
83bbd9b6 1003 }
73774bc7 1004
e3f049a8 1005 return 0;
9ae8ffe7
JL
1006
1007 case MEM:
1008 /* Check for an argument passed in memory. Only record in the
1009 copying-arguments block; it is too hard to track changes
1010 otherwise. */
1011 if (copying_arguments
1012 && (XEXP (src, 0) == arg_pointer_rtx
1013 || (GET_CODE (XEXP (src, 0)) == PLUS
1014 && XEXP (XEXP (src, 0), 0) == arg_pointer_rtx)))
38a448ca 1015 return gen_rtx_ADDRESS (VOIDmode, src);
9ae8ffe7
JL
1016 return 0;
1017
1018 case CONST:
1019 src = XEXP (src, 0);
1020 if (GET_CODE (src) != PLUS && GET_CODE (src) != MINUS)
1021 break;
d4b60170 1022
ec5c56db 1023 /* ... fall through ... */
2a2c8203 1024
9ae8ffe7
JL
1025 case PLUS:
1026 case MINUS:
2a2c8203 1027 {
ec907dd8
JL
1028 rtx temp, src_0 = XEXP (src, 0), src_1 = XEXP (src, 1);
1029
0134bf2d
DE
1030 /* If either operand is a REG that is a known pointer, then it
1031 is the base. */
1032 if (REG_P (src_0) && REG_POINTER (src_0))
1033 return find_base_value (src_0);
1034 if (REG_P (src_1) && REG_POINTER (src_1))
1035 return find_base_value (src_1);
1036
ec907dd8
JL
1037 /* If either operand is a REG, then see if we already have
1038 a known value for it. */
0134bf2d 1039 if (REG_P (src_0))
ec907dd8
JL
1040 {
1041 temp = find_base_value (src_0);
d4b60170 1042 if (temp != 0)
ec907dd8
JL
1043 src_0 = temp;
1044 }
1045
0134bf2d 1046 if (REG_P (src_1))
ec907dd8
JL
1047 {
1048 temp = find_base_value (src_1);
d4b60170 1049 if (temp!= 0)
ec907dd8
JL
1050 src_1 = temp;
1051 }
2a2c8203 1052
0134bf2d
DE
1053 /* If either base is named object or a special address
1054 (like an argument or stack reference), then use it for the
1055 base term. */
1056 if (src_0 != 0
1057 && (GET_CODE (src_0) == SYMBOL_REF
1058 || GET_CODE (src_0) == LABEL_REF
1059 || (GET_CODE (src_0) == ADDRESS
1060 && GET_MODE (src_0) != VOIDmode)))
1061 return src_0;
1062
1063 if (src_1 != 0
1064 && (GET_CODE (src_1) == SYMBOL_REF
1065 || GET_CODE (src_1) == LABEL_REF
1066 || (GET_CODE (src_1) == ADDRESS
1067 && GET_MODE (src_1) != VOIDmode)))
1068 return src_1;
1069
d4b60170 1070 /* Guess which operand is the base address:
ec907dd8
JL
1071 If either operand is a symbol, then it is the base. If
1072 either operand is a CONST_INT, then the other is the base. */
481683e1 1073 if (CONST_INT_P (src_1) || CONSTANT_P (src_0))
2a2c8203 1074 return find_base_value (src_0);
481683e1 1075 else if (CONST_INT_P (src_0) || CONSTANT_P (src_1))
ec907dd8
JL
1076 return find_base_value (src_1);
1077
9ae8ffe7 1078 return 0;
2a2c8203
JC
1079 }
1080
1081 case LO_SUM:
1082 /* The standard form is (lo_sum reg sym) so look only at the
1083 second operand. */
1084 return find_base_value (XEXP (src, 1));
9ae8ffe7
JL
1085
1086 case AND:
1087 /* If the second operand is constant set the base
ec5c56db 1088 address to the first operand. */
481683e1 1089 if (CONST_INT_P (XEXP (src, 1)) && INTVAL (XEXP (src, 1)) != 0)
2a2c8203 1090 return find_base_value (XEXP (src, 0));
9ae8ffe7
JL
1091 return 0;
1092
61f0131c 1093 case TRUNCATE:
d4ebfa65
BE
1094 /* As we do not know which address space the pointer is refering to, we can
1095 handle this only if the target does not support different pointer or
1096 address modes depending on the address space. */
1097 if (!target_default_pointer_address_modes_p ())
1098 break;
61f0131c
R
1099 if (GET_MODE_SIZE (GET_MODE (src)) < GET_MODE_SIZE (Pmode))
1100 break;
1101 /* Fall through. */
9ae8ffe7 1102 case HIGH:
d288e53d
DE
1103 case PRE_INC:
1104 case PRE_DEC:
1105 case POST_INC:
1106 case POST_DEC:
1107 case PRE_MODIFY:
1108 case POST_MODIFY:
2a2c8203 1109 return find_base_value (XEXP (src, 0));
1d300e19 1110
0aacc8ed
RK
1111 case ZERO_EXTEND:
1112 case SIGN_EXTEND: /* used for NT/Alpha pointers */
d4ebfa65
BE
1113 /* As we do not know which address space the pointer is refering to, we can
1114 handle this only if the target does not support different pointer or
1115 address modes depending on the address space. */
1116 if (!target_default_pointer_address_modes_p ())
1117 break;
1118
0aacc8ed
RK
1119 {
1120 rtx temp = find_base_value (XEXP (src, 0));
1121
5ae6cd0d 1122 if (temp != 0 && CONSTANT_P (temp))
0aacc8ed 1123 temp = convert_memory_address (Pmode, temp);
0aacc8ed
RK
1124
1125 return temp;
1126 }
1127
1d300e19
KG
1128 default:
1129 break;
9ae8ffe7
JL
1130 }
1131
1132 return 0;
1133}
1134
1135/* Called from init_alias_analysis indirectly through note_stores. */
1136
d4b60170 1137/* While scanning insns to find base values, reg_seen[N] is nonzero if
9ae8ffe7
JL
1138 register N has been set in this function. */
1139static char *reg_seen;
1140
13309a5f
JC
1141/* Addresses which are known not to alias anything else are identified
1142 by a unique integer. */
ec907dd8
JL
1143static int unique_id;
1144
2a2c8203 1145static void
7bc980e1 1146record_set (rtx dest, const_rtx set, void *data ATTRIBUTE_UNUSED)
9ae8ffe7 1147{
b3694847 1148 unsigned regno;
9ae8ffe7 1149 rtx src;
c28b4e40 1150 int n;
9ae8ffe7 1151
f8cfc6aa 1152 if (!REG_P (dest))
9ae8ffe7
JL
1153 return;
1154
fb6754f0 1155 regno = REGNO (dest);
9ae8ffe7 1156
7a40b8b1 1157 gcc_checking_assert (regno < VEC_length (rtx, reg_base_value));
ac606739 1158
c28b4e40
JW
1159 /* If this spans multiple hard registers, then we must indicate that every
1160 register has an unusable value. */
1161 if (regno < FIRST_PSEUDO_REGISTER)
66fd46b6 1162 n = hard_regno_nregs[regno][GET_MODE (dest)];
c28b4e40
JW
1163 else
1164 n = 1;
1165 if (n != 1)
1166 {
1167 while (--n >= 0)
1168 {
1169 reg_seen[regno + n] = 1;
1170 new_reg_base_value[regno + n] = 0;
1171 }
1172 return;
1173 }
1174
9ae8ffe7
JL
1175 if (set)
1176 {
1177 /* A CLOBBER wipes out any old value but does not prevent a previously
1178 unset register from acquiring a base address (i.e. reg_seen is not
1179 set). */
1180 if (GET_CODE (set) == CLOBBER)
1181 {
ec907dd8 1182 new_reg_base_value[regno] = 0;
9ae8ffe7
JL
1183 return;
1184 }
1185 src = SET_SRC (set);
1186 }
1187 else
1188 {
9ae8ffe7
JL
1189 if (reg_seen[regno])
1190 {
ec907dd8 1191 new_reg_base_value[regno] = 0;
9ae8ffe7
JL
1192 return;
1193 }
1194 reg_seen[regno] = 1;
38a448ca
RH
1195 new_reg_base_value[regno] = gen_rtx_ADDRESS (Pmode,
1196 GEN_INT (unique_id++));
9ae8ffe7
JL
1197 return;
1198 }
1199
5da6f168
RS
1200 /* If this is not the first set of REGNO, see whether the new value
1201 is related to the old one. There are two cases of interest:
1202
1203 (1) The register might be assigned an entirely new value
1204 that has the same base term as the original set.
1205
1206 (2) The set might be a simple self-modification that
1207 cannot change REGNO's base value.
1208
1209 If neither case holds, reject the original base value as invalid.
1210 Note that the following situation is not detected:
1211
c22cacf3 1212 extern int x, y; int *p = &x; p += (&y-&x);
5da6f168 1213
9ae8ffe7
JL
1214 ANSI C does not allow computing the difference of addresses
1215 of distinct top level objects. */
5da6f168
RS
1216 if (new_reg_base_value[regno] != 0
1217 && find_base_value (src) != new_reg_base_value[regno])
9ae8ffe7
JL
1218 switch (GET_CODE (src))
1219 {
2a2c8203 1220 case LO_SUM:
9ae8ffe7
JL
1221 case MINUS:
1222 if (XEXP (src, 0) != dest && XEXP (src, 1) != dest)
ec907dd8 1223 new_reg_base_value[regno] = 0;
9ae8ffe7 1224 break;
61f0131c
R
1225 case PLUS:
1226 /* If the value we add in the PLUS is also a valid base value,
1227 this might be the actual base value, and the original value
1228 an index. */
1229 {
1230 rtx other = NULL_RTX;
1231
1232 if (XEXP (src, 0) == dest)
1233 other = XEXP (src, 1);
1234 else if (XEXP (src, 1) == dest)
1235 other = XEXP (src, 0);
1236
1237 if (! other || find_base_value (other))
1238 new_reg_base_value[regno] = 0;
1239 break;
1240 }
9ae8ffe7 1241 case AND:
481683e1 1242 if (XEXP (src, 0) != dest || !CONST_INT_P (XEXP (src, 1)))
ec907dd8 1243 new_reg_base_value[regno] = 0;
9ae8ffe7 1244 break;
9ae8ffe7 1245 default:
ec907dd8 1246 new_reg_base_value[regno] = 0;
9ae8ffe7
JL
1247 break;
1248 }
1249 /* If this is the first set of a register, record the value. */
1250 else if ((regno >= FIRST_PSEUDO_REGISTER || ! fixed_regs[regno])
ec907dd8
JL
1251 && ! reg_seen[regno] && new_reg_base_value[regno] == 0)
1252 new_reg_base_value[regno] = find_base_value (src);
9ae8ffe7
JL
1253
1254 reg_seen[regno] = 1;
1255}
1256
bb1acb3e
RH
1257/* If a value is known for REGNO, return it. */
1258
c22cacf3 1259rtx
bb1acb3e
RH
1260get_reg_known_value (unsigned int regno)
1261{
1262 if (regno >= FIRST_PSEUDO_REGISTER)
1263 {
1264 regno -= FIRST_PSEUDO_REGISTER;
1265 if (regno < reg_known_value_size)
1266 return reg_known_value[regno];
1267 }
1268 return NULL;
43fe47ca
JW
1269}
1270
bb1acb3e
RH
1271/* Set it. */
1272
1273static void
1274set_reg_known_value (unsigned int regno, rtx val)
1275{
1276 if (regno >= FIRST_PSEUDO_REGISTER)
1277 {
1278 regno -= FIRST_PSEUDO_REGISTER;
1279 if (regno < reg_known_value_size)
1280 reg_known_value[regno] = val;
1281 }
1282}
1283
1284/* Similarly for reg_known_equiv_p. */
1285
1286bool
1287get_reg_known_equiv_p (unsigned int regno)
1288{
1289 if (regno >= FIRST_PSEUDO_REGISTER)
1290 {
1291 regno -= FIRST_PSEUDO_REGISTER;
1292 if (regno < reg_known_value_size)
1293 return reg_known_equiv_p[regno];
1294 }
1295 return false;
1296}
1297
1298static void
1299set_reg_known_equiv_p (unsigned int regno, bool val)
1300{
1301 if (regno >= FIRST_PSEUDO_REGISTER)
1302 {
1303 regno -= FIRST_PSEUDO_REGISTER;
1304 if (regno < reg_known_value_size)
1305 reg_known_equiv_p[regno] = val;
1306 }
1307}
1308
1309
db048faf
MM
1310/* Returns a canonical version of X, from the point of view alias
1311 analysis. (For example, if X is a MEM whose address is a register,
1312 and the register has a known value (say a SYMBOL_REF), then a MEM
1313 whose address is the SYMBOL_REF is returned.) */
1314
1315rtx
4682ae04 1316canon_rtx (rtx x)
9ae8ffe7
JL
1317{
1318 /* Recursively look for equivalences. */
f8cfc6aa 1319 if (REG_P (x) && REGNO (x) >= FIRST_PSEUDO_REGISTER)
bb1acb3e
RH
1320 {
1321 rtx t = get_reg_known_value (REGNO (x));
1322 if (t == x)
1323 return x;
1324 if (t)
1325 return canon_rtx (t);
1326 }
1327
1328 if (GET_CODE (x) == PLUS)
9ae8ffe7
JL
1329 {
1330 rtx x0 = canon_rtx (XEXP (x, 0));
1331 rtx x1 = canon_rtx (XEXP (x, 1));
1332
1333 if (x0 != XEXP (x, 0) || x1 != XEXP (x, 1))
1334 {
481683e1 1335 if (CONST_INT_P (x0))
ed8908e7 1336 return plus_constant (x1, INTVAL (x0));
481683e1 1337 else if (CONST_INT_P (x1))
ed8908e7 1338 return plus_constant (x0, INTVAL (x1));
38a448ca 1339 return gen_rtx_PLUS (GET_MODE (x), x0, x1);
9ae8ffe7
JL
1340 }
1341 }
d4b60170 1342
9ae8ffe7
JL
1343 /* This gives us much better alias analysis when called from
1344 the loop optimizer. Note we want to leave the original
1345 MEM alone, but need to return the canonicalized MEM with
1346 all the flags with their original values. */
3c0cb5de 1347 else if (MEM_P (x))
f1ec5147 1348 x = replace_equiv_address_nv (x, canon_rtx (XEXP (x, 0)));
d4b60170 1349
9ae8ffe7
JL
1350 return x;
1351}
1352
1353/* Return 1 if X and Y are identical-looking rtx's.
45183e03 1354 Expect that X and Y has been already canonicalized.
9ae8ffe7
JL
1355
1356 We use the data in reg_known_value above to see if two registers with
1357 different numbers are, in fact, equivalent. */
1358
1359static int
ed7a4b4b 1360rtx_equal_for_memref_p (const_rtx x, const_rtx y)
9ae8ffe7 1361{
b3694847
SS
1362 int i;
1363 int j;
1364 enum rtx_code code;
1365 const char *fmt;
9ae8ffe7
JL
1366
1367 if (x == 0 && y == 0)
1368 return 1;
1369 if (x == 0 || y == 0)
1370 return 0;
d4b60170 1371
9ae8ffe7
JL
1372 if (x == y)
1373 return 1;
1374
1375 code = GET_CODE (x);
1376 /* Rtx's of different codes cannot be equal. */
1377 if (code != GET_CODE (y))
1378 return 0;
1379
1380 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent.
1381 (REG:SI x) and (REG:HI x) are NOT equivalent. */
1382
1383 if (GET_MODE (x) != GET_MODE (y))
1384 return 0;
1385
db048faf
MM
1386 /* Some RTL can be compared without a recursive examination. */
1387 switch (code)
1388 {
1389 case REG:
1390 return REGNO (x) == REGNO (y);
1391
1392 case LABEL_REF:
1393 return XEXP (x, 0) == XEXP (y, 0);
ca7fd9cd 1394
db048faf
MM
1395 case SYMBOL_REF:
1396 return XSTR (x, 0) == XSTR (y, 0);
1397
40e02b4a 1398 case VALUE:
db048faf
MM
1399 case CONST_INT:
1400 case CONST_DOUBLE:
091a3ac7 1401 case CONST_FIXED:
db048faf
MM
1402 /* There's no need to compare the contents of CONST_DOUBLEs or
1403 CONST_INTs because pointer equality is a good enough
1404 comparison for these nodes. */
1405 return 0;
1406
db048faf
MM
1407 default:
1408 break;
1409 }
9ae8ffe7 1410
45183e03
JH
1411 /* canon_rtx knows how to handle plus. No need to canonicalize. */
1412 if (code == PLUS)
9ae8ffe7
JL
1413 return ((rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 0))
1414 && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 1)))
1415 || (rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 1))
1416 && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 0))));
45183e03
JH
1417 /* For commutative operations, the RTX match if the operand match in any
1418 order. Also handle the simple binary and unary cases without a loop. */
ec8e098d 1419 if (COMMUTATIVE_P (x))
45183e03
JH
1420 {
1421 rtx xop0 = canon_rtx (XEXP (x, 0));
1422 rtx yop0 = canon_rtx (XEXP (y, 0));
1423 rtx yop1 = canon_rtx (XEXP (y, 1));
1424
1425 return ((rtx_equal_for_memref_p (xop0, yop0)
1426 && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), yop1))
1427 || (rtx_equal_for_memref_p (xop0, yop1)
1428 && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), yop0)));
1429 }
ec8e098d 1430 else if (NON_COMMUTATIVE_P (x))
45183e03
JH
1431 {
1432 return (rtx_equal_for_memref_p (canon_rtx (XEXP (x, 0)),
4682ae04 1433 canon_rtx (XEXP (y, 0)))
45183e03
JH
1434 && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)),
1435 canon_rtx (XEXP (y, 1))));
1436 }
ec8e098d 1437 else if (UNARY_P (x))
45183e03 1438 return rtx_equal_for_memref_p (canon_rtx (XEXP (x, 0)),
4682ae04 1439 canon_rtx (XEXP (y, 0)));
9ae8ffe7
JL
1440
1441 /* Compare the elements. If any pair of corresponding elements
de12be17
JC
1442 fail to match, return 0 for the whole things.
1443
1444 Limit cases to types which actually appear in addresses. */
9ae8ffe7
JL
1445
1446 fmt = GET_RTX_FORMAT (code);
1447 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
1448 {
1449 switch (fmt[i])
1450 {
9ae8ffe7
JL
1451 case 'i':
1452 if (XINT (x, i) != XINT (y, i))
1453 return 0;
1454 break;
1455
9ae8ffe7
JL
1456 case 'E':
1457 /* Two vectors must have the same length. */
1458 if (XVECLEN (x, i) != XVECLEN (y, i))
1459 return 0;
1460
1461 /* And the corresponding elements must match. */
1462 for (j = 0; j < XVECLEN (x, i); j++)
45183e03
JH
1463 if (rtx_equal_for_memref_p (canon_rtx (XVECEXP (x, i, j)),
1464 canon_rtx (XVECEXP (y, i, j))) == 0)
9ae8ffe7
JL
1465 return 0;
1466 break;
1467
1468 case 'e':
45183e03
JH
1469 if (rtx_equal_for_memref_p (canon_rtx (XEXP (x, i)),
1470 canon_rtx (XEXP (y, i))) == 0)
9ae8ffe7
JL
1471 return 0;
1472 break;
1473
3237ac18
AH
1474 /* This can happen for asm operands. */
1475 case 's':
1476 if (strcmp (XSTR (x, i), XSTR (y, i)))
1477 return 0;
1478 break;
1479
aee21ba9
JL
1480 /* This can happen for an asm which clobbers memory. */
1481 case '0':
1482 break;
1483
9ae8ffe7
JL
1484 /* It is believed that rtx's at this level will never
1485 contain anything but integers and other rtx's,
1486 except for within LABEL_REFs and SYMBOL_REFs. */
1487 default:
298e6adc 1488 gcc_unreachable ();
9ae8ffe7
JL
1489 }
1490 }
1491 return 1;
1492}
1493
94f24ddc 1494rtx
4682ae04 1495find_base_term (rtx x)
9ae8ffe7 1496{
eab5c70a
BS
1497 cselib_val *val;
1498 struct elt_loc_list *l;
1499
b949ea8b
JW
1500#if defined (FIND_BASE_TERM)
1501 /* Try machine-dependent ways to find the base term. */
1502 x = FIND_BASE_TERM (x);
1503#endif
1504
9ae8ffe7
JL
1505 switch (GET_CODE (x))
1506 {
1507 case REG:
1508 return REG_BASE_VALUE (x);
1509
d288e53d 1510 case TRUNCATE:
d4ebfa65
BE
1511 /* As we do not know which address space the pointer is refering to, we can
1512 handle this only if the target does not support different pointer or
1513 address modes depending on the address space. */
1514 if (!target_default_pointer_address_modes_p ())
1515 return 0;
d288e53d 1516 if (GET_MODE_SIZE (GET_MODE (x)) < GET_MODE_SIZE (Pmode))
ca7fd9cd 1517 return 0;
d288e53d 1518 /* Fall through. */
9ae8ffe7 1519 case HIGH:
6d849a2a
JL
1520 case PRE_INC:
1521 case PRE_DEC:
1522 case POST_INC:
1523 case POST_DEC:
d288e53d
DE
1524 case PRE_MODIFY:
1525 case POST_MODIFY:
6d849a2a
JL
1526 return find_base_term (XEXP (x, 0));
1527
1abade85
RK
1528 case ZERO_EXTEND:
1529 case SIGN_EXTEND: /* Used for Alpha/NT pointers */
d4ebfa65
BE
1530 /* As we do not know which address space the pointer is refering to, we can
1531 handle this only if the target does not support different pointer or
1532 address modes depending on the address space. */
1533 if (!target_default_pointer_address_modes_p ())
1534 return 0;
1535
1abade85
RK
1536 {
1537 rtx temp = find_base_term (XEXP (x, 0));
1538
5ae6cd0d 1539 if (temp != 0 && CONSTANT_P (temp))
1abade85 1540 temp = convert_memory_address (Pmode, temp);
1abade85
RK
1541
1542 return temp;
1543 }
1544
eab5c70a
BS
1545 case VALUE:
1546 val = CSELIB_VAL_PTR (x);
40e02b4a
JH
1547 if (!val)
1548 return 0;
eab5c70a
BS
1549 for (l = val->locs; l; l = l->next)
1550 if ((x = find_base_term (l->loc)) != 0)
1551 return x;
1552 return 0;
1553
023f059b
JJ
1554 case LO_SUM:
1555 /* The standard form is (lo_sum reg sym) so look only at the
1556 second operand. */
1557 return find_base_term (XEXP (x, 1));
1558
9ae8ffe7
JL
1559 case CONST:
1560 x = XEXP (x, 0);
1561 if (GET_CODE (x) != PLUS && GET_CODE (x) != MINUS)
1562 return 0;
938d968e 1563 /* Fall through. */
9ae8ffe7
JL
1564 case PLUS:
1565 case MINUS:
1566 {
3c567fae
JL
1567 rtx tmp1 = XEXP (x, 0);
1568 rtx tmp2 = XEXP (x, 1);
1569
f5143c46 1570 /* This is a little bit tricky since we have to determine which of
3c567fae
JL
1571 the two operands represents the real base address. Otherwise this
1572 routine may return the index register instead of the base register.
1573
1574 That may cause us to believe no aliasing was possible, when in
1575 fact aliasing is possible.
1576
1577 We use a few simple tests to guess the base register. Additional
1578 tests can certainly be added. For example, if one of the operands
1579 is a shift or multiply, then it must be the index register and the
1580 other operand is the base register. */
ca7fd9cd 1581
b949ea8b
JW
1582 if (tmp1 == pic_offset_table_rtx && CONSTANT_P (tmp2))
1583 return find_base_term (tmp2);
1584
3c567fae
JL
1585 /* If either operand is known to be a pointer, then use it
1586 to determine the base term. */
3502dc9c 1587 if (REG_P (tmp1) && REG_POINTER (tmp1))
7eba2d1f
LM
1588 {
1589 rtx base = find_base_term (tmp1);
1590 if (base)
1591 return base;
1592 }
3c567fae 1593
3502dc9c 1594 if (REG_P (tmp2) && REG_POINTER (tmp2))
7eba2d1f
LM
1595 {
1596 rtx base = find_base_term (tmp2);
1597 if (base)
1598 return base;
1599 }
3c567fae
JL
1600
1601 /* Neither operand was known to be a pointer. Go ahead and find the
1602 base term for both operands. */
1603 tmp1 = find_base_term (tmp1);
1604 tmp2 = find_base_term (tmp2);
1605
1606 /* If either base term is named object or a special address
1607 (like an argument or stack reference), then use it for the
1608 base term. */
d4b60170 1609 if (tmp1 != 0
3c567fae
JL
1610 && (GET_CODE (tmp1) == SYMBOL_REF
1611 || GET_CODE (tmp1) == LABEL_REF
1612 || (GET_CODE (tmp1) == ADDRESS
1613 && GET_MODE (tmp1) != VOIDmode)))
1614 return tmp1;
1615
d4b60170 1616 if (tmp2 != 0
3c567fae
JL
1617 && (GET_CODE (tmp2) == SYMBOL_REF
1618 || GET_CODE (tmp2) == LABEL_REF
1619 || (GET_CODE (tmp2) == ADDRESS
1620 && GET_MODE (tmp2) != VOIDmode)))
1621 return tmp2;
1622
1623 /* We could not determine which of the two operands was the
1624 base register and which was the index. So we can determine
1625 nothing from the base alias check. */
1626 return 0;
9ae8ffe7
JL
1627 }
1628
1629 case AND:
481683e1 1630 if (CONST_INT_P (XEXP (x, 1)) && INTVAL (XEXP (x, 1)) != 0)
d288e53d 1631 return find_base_term (XEXP (x, 0));
9ae8ffe7
JL
1632 return 0;
1633
1634 case SYMBOL_REF:
1635 case LABEL_REF:
1636 return x;
1637
1638 default:
1639 return 0;
1640 }
1641}
1642
1643/* Return 0 if the addresses X and Y are known to point to different
1644 objects, 1 if they might be pointers to the same object. */
1645
1646static int
4682ae04
AJ
1647base_alias_check (rtx x, rtx y, enum machine_mode x_mode,
1648 enum machine_mode y_mode)
9ae8ffe7
JL
1649{
1650 rtx x_base = find_base_term (x);
1651 rtx y_base = find_base_term (y);
1652
1c72c7f6
JC
1653 /* If the address itself has no known base see if a known equivalent
1654 value has one. If either address still has no known base, nothing
1655 is known about aliasing. */
1656 if (x_base == 0)
1657 {
1658 rtx x_c;
d4b60170 1659
1c72c7f6
JC
1660 if (! flag_expensive_optimizations || (x_c = canon_rtx (x)) == x)
1661 return 1;
d4b60170 1662
1c72c7f6
JC
1663 x_base = find_base_term (x_c);
1664 if (x_base == 0)
1665 return 1;
1666 }
9ae8ffe7 1667
1c72c7f6
JC
1668 if (y_base == 0)
1669 {
1670 rtx y_c;
1671 if (! flag_expensive_optimizations || (y_c = canon_rtx (y)) == y)
1672 return 1;
d4b60170 1673
1c72c7f6
JC
1674 y_base = find_base_term (y_c);
1675 if (y_base == 0)
1676 return 1;
1677 }
1678
1679 /* If the base addresses are equal nothing is known about aliasing. */
1680 if (rtx_equal_p (x_base, y_base))
9ae8ffe7
JL
1681 return 1;
1682
435da628
UB
1683 /* The base addresses are different expressions. If they are not accessed
1684 via AND, there is no conflict. We can bring knowledge of object
1685 alignment into play here. For example, on alpha, "char a, b;" can
1686 alias one another, though "char a; long b;" cannot. AND addesses may
1687 implicitly alias surrounding objects; i.e. unaligned access in DImode
1688 via AND address can alias all surrounding object types except those
1689 with aligment 8 or higher. */
1690 if (GET_CODE (x) == AND && GET_CODE (y) == AND)
1691 return 1;
1692 if (GET_CODE (x) == AND
481683e1 1693 && (!CONST_INT_P (XEXP (x, 1))
435da628
UB
1694 || (int) GET_MODE_UNIT_SIZE (y_mode) < -INTVAL (XEXP (x, 1))))
1695 return 1;
1696 if (GET_CODE (y) == AND
481683e1 1697 && (!CONST_INT_P (XEXP (y, 1))
435da628
UB
1698 || (int) GET_MODE_UNIT_SIZE (x_mode) < -INTVAL (XEXP (y, 1))))
1699 return 1;
1700
1701 /* Differing symbols not accessed via AND never alias. */
9ae8ffe7 1702 if (GET_CODE (x_base) != ADDRESS && GET_CODE (y_base) != ADDRESS)
435da628 1703 return 0;
9ae8ffe7
JL
1704
1705 /* If one address is a stack reference there can be no alias:
1706 stack references using different base registers do not alias,
1707 a stack reference can not alias a parameter, and a stack reference
1708 can not alias a global. */
1709 if ((GET_CODE (x_base) == ADDRESS && GET_MODE (x_base) == Pmode)
1710 || (GET_CODE (y_base) == ADDRESS && GET_MODE (y_base) == Pmode))
1711 return 0;
1712
0d3c82d6 1713 return 1;
9ae8ffe7
JL
1714}
1715
eab5c70a
BS
1716/* Convert the address X into something we can use. This is done by returning
1717 it unchanged unless it is a value; in the latter case we call cselib to get
1718 a more useful rtx. */
3bdf5ad1 1719
a13d4ebf 1720rtx
4682ae04 1721get_addr (rtx x)
eab5c70a
BS
1722{
1723 cselib_val *v;
1724 struct elt_loc_list *l;
1725
1726 if (GET_CODE (x) != VALUE)
1727 return x;
1728 v = CSELIB_VAL_PTR (x);
40e02b4a
JH
1729 if (v)
1730 {
1731 for (l = v->locs; l; l = l->next)
1732 if (CONSTANT_P (l->loc))
1733 return l->loc;
1734 for (l = v->locs; l; l = l->next)
3c0cb5de 1735 if (!REG_P (l->loc) && !MEM_P (l->loc))
40e02b4a
JH
1736 return l->loc;
1737 if (v->locs)
1738 return v->locs->loc;
1739 }
eab5c70a
BS
1740 return x;
1741}
1742
39cec1ac
MH
1743/* Return the address of the (N_REFS + 1)th memory reference to ADDR
1744 where SIZE is the size in bytes of the memory reference. If ADDR
1745 is not modified by the memory reference then ADDR is returned. */
1746
04e2b4d3 1747static rtx
4682ae04 1748addr_side_effect_eval (rtx addr, int size, int n_refs)
39cec1ac
MH
1749{
1750 int offset = 0;
ca7fd9cd 1751
39cec1ac
MH
1752 switch (GET_CODE (addr))
1753 {
1754 case PRE_INC:
1755 offset = (n_refs + 1) * size;
1756 break;
1757 case PRE_DEC:
1758 offset = -(n_refs + 1) * size;
1759 break;
1760 case POST_INC:
1761 offset = n_refs * size;
1762 break;
1763 case POST_DEC:
1764 offset = -n_refs * size;
1765 break;
1766
1767 default:
1768 return addr;
1769 }
ca7fd9cd 1770
39cec1ac 1771 if (offset)
45183e03 1772 addr = gen_rtx_PLUS (GET_MODE (addr), XEXP (addr, 0),
c22cacf3 1773 GEN_INT (offset));
39cec1ac
MH
1774 else
1775 addr = XEXP (addr, 0);
45183e03 1776 addr = canon_rtx (addr);
39cec1ac
MH
1777
1778 return addr;
1779}
1780
f47e08d9
RG
1781/* Return one if X and Y (memory addresses) reference the
1782 same location in memory or if the references overlap.
1783 Return zero if they do not overlap, else return
1784 minus one in which case they still might reference the same location.
1785
1786 C is an offset accumulator. When
9ae8ffe7
JL
1787 C is nonzero, we are testing aliases between X and Y + C.
1788 XSIZE is the size in bytes of the X reference,
1789 similarly YSIZE is the size in bytes for Y.
45183e03 1790 Expect that canon_rtx has been already called for X and Y.
9ae8ffe7
JL
1791
1792 If XSIZE or YSIZE is zero, we do not know the amount of memory being
1793 referenced (the reference was BLKmode), so make the most pessimistic
1794 assumptions.
1795
c02f035f
RH
1796 If XSIZE or YSIZE is negative, we may access memory outside the object
1797 being referenced as a side effect. This can happen when using AND to
1798 align memory references, as is done on the Alpha.
1799
9ae8ffe7 1800 Nice to notice that varying addresses cannot conflict with fp if no
f47e08d9
RG
1801 local variables had their addresses taken, but that's too hard now.
1802
1803 ??? Contrary to the tree alias oracle this does not return
1804 one for X + non-constant and Y + non-constant when X and Y are equal.
1805 If that is fixed the TBAA hack for union type-punning can be removed. */
9ae8ffe7 1806
9ae8ffe7 1807static int
4682ae04 1808memrefs_conflict_p (int xsize, rtx x, int ysize, rtx y, HOST_WIDE_INT c)
9ae8ffe7 1809{
eab5c70a 1810 if (GET_CODE (x) == VALUE)
5312b066
JJ
1811 {
1812 if (REG_P (y))
1813 {
24f8d71e
JJ
1814 struct elt_loc_list *l = NULL;
1815 if (CSELIB_VAL_PTR (x))
1816 for (l = CSELIB_VAL_PTR (x)->locs; l; l = l->next)
1817 if (REG_P (l->loc) && rtx_equal_for_memref_p (l->loc, y))
1818 break;
5312b066
JJ
1819 if (l)
1820 x = y;
1821 else
1822 x = get_addr (x);
1823 }
1824 /* Don't call get_addr if y is the same VALUE. */
1825 else if (x != y)
1826 x = get_addr (x);
1827 }
eab5c70a 1828 if (GET_CODE (y) == VALUE)
5312b066
JJ
1829 {
1830 if (REG_P (x))
1831 {
24f8d71e
JJ
1832 struct elt_loc_list *l = NULL;
1833 if (CSELIB_VAL_PTR (y))
1834 for (l = CSELIB_VAL_PTR (y)->locs; l; l = l->next)
1835 if (REG_P (l->loc) && rtx_equal_for_memref_p (l->loc, x))
1836 break;
5312b066
JJ
1837 if (l)
1838 y = x;
1839 else
1840 y = get_addr (y);
1841 }
1842 /* Don't call get_addr if x is the same VALUE. */
1843 else if (y != x)
1844 y = get_addr (y);
1845 }
9ae8ffe7
JL
1846 if (GET_CODE (x) == HIGH)
1847 x = XEXP (x, 0);
1848 else if (GET_CODE (x) == LO_SUM)
1849 x = XEXP (x, 1);
1850 else
45183e03 1851 x = addr_side_effect_eval (x, xsize, 0);
9ae8ffe7
JL
1852 if (GET_CODE (y) == HIGH)
1853 y = XEXP (y, 0);
1854 else if (GET_CODE (y) == LO_SUM)
1855 y = XEXP (y, 1);
1856 else
45183e03 1857 y = addr_side_effect_eval (y, ysize, 0);
9ae8ffe7
JL
1858
1859 if (rtx_equal_for_memref_p (x, y))
1860 {
c02f035f 1861 if (xsize <= 0 || ysize <= 0)
9ae8ffe7
JL
1862 return 1;
1863 if (c >= 0 && xsize > c)
1864 return 1;
1865 if (c < 0 && ysize+c > 0)
1866 return 1;
1867 return 0;
1868 }
1869
6e73e666
JC
1870 /* This code used to check for conflicts involving stack references and
1871 globals but the base address alias code now handles these cases. */
9ae8ffe7
JL
1872
1873 if (GET_CODE (x) == PLUS)
1874 {
1875 /* The fact that X is canonicalized means that this
1876 PLUS rtx is canonicalized. */
1877 rtx x0 = XEXP (x, 0);
1878 rtx x1 = XEXP (x, 1);
1879
1880 if (GET_CODE (y) == PLUS)
1881 {
1882 /* The fact that Y is canonicalized means that this
1883 PLUS rtx is canonicalized. */
1884 rtx y0 = XEXP (y, 0);
1885 rtx y1 = XEXP (y, 1);
1886
1887 if (rtx_equal_for_memref_p (x1, y1))
1888 return memrefs_conflict_p (xsize, x0, ysize, y0, c);
1889 if (rtx_equal_for_memref_p (x0, y0))
1890 return memrefs_conflict_p (xsize, x1, ysize, y1, c);
481683e1 1891 if (CONST_INT_P (x1))
63be02db 1892 {
481683e1 1893 if (CONST_INT_P (y1))
63be02db
JM
1894 return memrefs_conflict_p (xsize, x0, ysize, y0,
1895 c - INTVAL (x1) + INTVAL (y1));
1896 else
1897 return memrefs_conflict_p (xsize, x0, ysize, y,
1898 c - INTVAL (x1));
1899 }
481683e1 1900 else if (CONST_INT_P (y1))
9ae8ffe7
JL
1901 return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1));
1902
f47e08d9 1903 return -1;
9ae8ffe7 1904 }
481683e1 1905 else if (CONST_INT_P (x1))
9ae8ffe7
JL
1906 return memrefs_conflict_p (xsize, x0, ysize, y, c - INTVAL (x1));
1907 }
1908 else if (GET_CODE (y) == PLUS)
1909 {
1910 /* The fact that Y is canonicalized means that this
1911 PLUS rtx is canonicalized. */
1912 rtx y0 = XEXP (y, 0);
1913 rtx y1 = XEXP (y, 1);
1914
481683e1 1915 if (CONST_INT_P (y1))
9ae8ffe7
JL
1916 return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1));
1917 else
f47e08d9 1918 return -1;
9ae8ffe7
JL
1919 }
1920
1921 if (GET_CODE (x) == GET_CODE (y))
1922 switch (GET_CODE (x))
1923 {
1924 case MULT:
1925 {
1926 /* Handle cases where we expect the second operands to be the
1927 same, and check only whether the first operand would conflict
1928 or not. */
1929 rtx x0, y0;
1930 rtx x1 = canon_rtx (XEXP (x, 1));
1931 rtx y1 = canon_rtx (XEXP (y, 1));
1932 if (! rtx_equal_for_memref_p (x1, y1))
f47e08d9 1933 return -1;
9ae8ffe7
JL
1934 x0 = canon_rtx (XEXP (x, 0));
1935 y0 = canon_rtx (XEXP (y, 0));
1936 if (rtx_equal_for_memref_p (x0, y0))
1937 return (xsize == 0 || ysize == 0
1938 || (c >= 0 && xsize > c) || (c < 0 && ysize+c > 0));
1939
1940 /* Can't properly adjust our sizes. */
481683e1 1941 if (!CONST_INT_P (x1))
f47e08d9 1942 return -1;
9ae8ffe7
JL
1943 xsize /= INTVAL (x1);
1944 ysize /= INTVAL (x1);
1945 c /= INTVAL (x1);
1946 return memrefs_conflict_p (xsize, x0, ysize, y0, c);
1947 }
1d300e19
KG
1948
1949 default:
1950 break;
9ae8ffe7
JL
1951 }
1952
1953 /* Treat an access through an AND (e.g. a subword access on an Alpha)
ca7fd9cd 1954 as an access with indeterminate size. Assume that references
56ee9281
RH
1955 besides AND are aligned, so if the size of the other reference is
1956 at least as large as the alignment, assume no other overlap. */
481683e1 1957 if (GET_CODE (x) == AND && CONST_INT_P (XEXP (x, 1)))
56ee9281 1958 {
02e3377d 1959 if (GET_CODE (y) == AND || ysize < -INTVAL (XEXP (x, 1)))
56ee9281 1960 xsize = -1;
45183e03 1961 return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), ysize, y, c);
56ee9281 1962 }
481683e1 1963 if (GET_CODE (y) == AND && CONST_INT_P (XEXP (y, 1)))
c02f035f 1964 {
56ee9281 1965 /* ??? If we are indexing far enough into the array/structure, we
ca7fd9cd 1966 may yet be able to determine that we can not overlap. But we
c02f035f 1967 also need to that we are far enough from the end not to overlap
56ee9281 1968 a following reference, so we do nothing with that for now. */
02e3377d 1969 if (GET_CODE (x) == AND || xsize < -INTVAL (XEXP (y, 1)))
56ee9281 1970 ysize = -1;
45183e03 1971 return memrefs_conflict_p (xsize, x, ysize, canon_rtx (XEXP (y, 0)), c);
c02f035f 1972 }
9ae8ffe7
JL
1973
1974 if (CONSTANT_P (x))
1975 {
481683e1 1976 if (CONST_INT_P (x) && CONST_INT_P (y))
9ae8ffe7
JL
1977 {
1978 c += (INTVAL (y) - INTVAL (x));
c02f035f 1979 return (xsize <= 0 || ysize <= 0
9ae8ffe7
JL
1980 || (c >= 0 && xsize > c) || (c < 0 && ysize+c > 0));
1981 }
1982
1983 if (GET_CODE (x) == CONST)
1984 {
1985 if (GET_CODE (y) == CONST)
1986 return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)),
1987 ysize, canon_rtx (XEXP (y, 0)), c);
1988 else
1989 return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)),
1990 ysize, y, c);
1991 }
1992 if (GET_CODE (y) == CONST)
1993 return memrefs_conflict_p (xsize, x, ysize,
1994 canon_rtx (XEXP (y, 0)), c);
1995
1996 if (CONSTANT_P (y))
b949ea8b 1997 return (xsize <= 0 || ysize <= 0
c02f035f 1998 || (rtx_equal_for_memref_p (x, y)
b949ea8b 1999 && ((c >= 0 && xsize > c) || (c < 0 && ysize+c > 0))));
9ae8ffe7 2000
f47e08d9 2001 return -1;
9ae8ffe7 2002 }
f47e08d9
RG
2003
2004 return -1;
9ae8ffe7
JL
2005}
2006
2007/* Functions to compute memory dependencies.
2008
2009 Since we process the insns in execution order, we can build tables
2010 to keep track of what registers are fixed (and not aliased), what registers
2011 are varying in known ways, and what registers are varying in unknown
2012 ways.
2013
2014 If both memory references are volatile, then there must always be a
2015 dependence between the two references, since their order can not be
2016 changed. A volatile and non-volatile reference can be interchanged
ca7fd9cd 2017 though.
9ae8ffe7 2018
dc1618bc
RK
2019 A MEM_IN_STRUCT reference at a non-AND varying address can never
2020 conflict with a non-MEM_IN_STRUCT reference at a fixed address. We
2021 also must allow AND addresses, because they may generate accesses
2022 outside the object being referenced. This is used to generate
2023 aligned addresses from unaligned addresses, for instance, the alpha
2024 storeqi_unaligned pattern. */
9ae8ffe7
JL
2025
2026/* Read dependence: X is read after read in MEM takes place. There can
2027 only be a dependence here if both reads are volatile. */
2028
2029int
4f588890 2030read_dependence (const_rtx mem, const_rtx x)
9ae8ffe7
JL
2031{
2032 return MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem);
2033}
2034
c6df88cb
MM
2035/* Returns MEM1 if and only if MEM1 is a scalar at a fixed address and
2036 MEM2 is a reference to a structure at a varying address, or returns
2037 MEM2 if vice versa. Otherwise, returns NULL_RTX. If a non-NULL
2038 value is returned MEM1 and MEM2 can never alias. VARIES_P is used
2039 to decide whether or not an address may vary; it should return
eab5c70a
BS
2040 nonzero whenever variation is possible.
2041 MEM1_ADDR and MEM2_ADDR are the addresses of MEM1 and MEM2. */
ca7fd9cd 2042
4f588890
KG
2043static const_rtx
2044fixed_scalar_and_varying_struct_p (const_rtx mem1, const_rtx mem2, rtx mem1_addr,
4682ae04 2045 rtx mem2_addr,
4f588890 2046 bool (*varies_p) (const_rtx, bool))
ca7fd9cd 2047{
3e0abe15
GK
2048 if (! flag_strict_aliasing)
2049 return NULL_RTX;
2050
afa8f0fb
AP
2051 if (MEM_ALIAS_SET (mem2)
2052 && MEM_SCALAR_P (mem1) && MEM_IN_STRUCT_P (mem2)
e38fe8e0 2053 && !varies_p (mem1_addr, 1) && varies_p (mem2_addr, 1))
c6df88cb
MM
2054 /* MEM1 is a scalar at a fixed address; MEM2 is a struct at a
2055 varying address. */
2056 return mem1;
2057
afa8f0fb
AP
2058 if (MEM_ALIAS_SET (mem1)
2059 && MEM_IN_STRUCT_P (mem1) && MEM_SCALAR_P (mem2)
e38fe8e0 2060 && varies_p (mem1_addr, 1) && !varies_p (mem2_addr, 1))
c6df88cb
MM
2061 /* MEM2 is a scalar at a fixed address; MEM1 is a struct at a
2062 varying address. */
2063 return mem2;
2064
2065 return NULL_RTX;
2066}
2067
2068/* Returns nonzero if something about the mode or address format MEM1
2069 indicates that it might well alias *anything*. */
2070
2c72b78f 2071static int
4f588890 2072aliases_everything_p (const_rtx mem)
c6df88cb 2073{
c6df88cb 2074 if (GET_CODE (XEXP (mem, 0)) == AND)
35fd3193 2075 /* If the address is an AND, it's very hard to know at what it is
c6df88cb
MM
2076 actually pointing. */
2077 return 1;
ca7fd9cd 2078
c6df88cb
MM
2079 return 0;
2080}
2081
998d7deb
RH
2082/* Return true if we can determine that the fields referenced cannot
2083 overlap for any pair of objects. */
2084
2085static bool
4f588890 2086nonoverlapping_component_refs_p (const_tree x, const_tree y)
998d7deb 2087{
4f588890 2088 const_tree fieldx, fieldy, typex, typey, orig_y;
998d7deb 2089
4c7af939
AB
2090 if (!flag_strict_aliasing)
2091 return false;
2092
998d7deb
RH
2093 do
2094 {
2095 /* The comparison has to be done at a common type, since we don't
d6a7951f 2096 know how the inheritance hierarchy works. */
998d7deb
RH
2097 orig_y = y;
2098 do
2099 {
2100 fieldx = TREE_OPERAND (x, 1);
c05a0766 2101 typex = TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (fieldx));
998d7deb
RH
2102
2103 y = orig_y;
2104 do
2105 {
2106 fieldy = TREE_OPERAND (y, 1);
c05a0766 2107 typey = TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (fieldy));
998d7deb
RH
2108
2109 if (typex == typey)
2110 goto found;
2111
2112 y = TREE_OPERAND (y, 0);
2113 }
2114 while (y && TREE_CODE (y) == COMPONENT_REF);
2115
2116 x = TREE_OPERAND (x, 0);
2117 }
2118 while (x && TREE_CODE (x) == COMPONENT_REF);
998d7deb 2119 /* Never found a common type. */
c05a0766 2120 return false;
998d7deb
RH
2121
2122 found:
2123 /* If we're left with accessing different fields of a structure,
2124 then no overlap. */
2125 if (TREE_CODE (typex) == RECORD_TYPE
2126 && fieldx != fieldy)
2127 return true;
2128
2129 /* The comparison on the current field failed. If we're accessing
2130 a very nested structure, look at the next outer level. */
2131 x = TREE_OPERAND (x, 0);
2132 y = TREE_OPERAND (y, 0);
2133 }
2134 while (x && y
2135 && TREE_CODE (x) == COMPONENT_REF
2136 && TREE_CODE (y) == COMPONENT_REF);
ca7fd9cd 2137
998d7deb
RH
2138 return false;
2139}
2140
2141/* Look at the bottom of the COMPONENT_REF list for a DECL, and return it. */
2142
2143static tree
4682ae04 2144decl_for_component_ref (tree x)
998d7deb
RH
2145{
2146 do
2147 {
2148 x = TREE_OPERAND (x, 0);
2149 }
2150 while (x && TREE_CODE (x) == COMPONENT_REF);
2151
2152 return x && DECL_P (x) ? x : NULL_TREE;
2153}
2154
2155/* Walk up the COMPONENT_REF list and adjust OFFSET to compensate for the
2156 offset of the field reference. */
2157
2158static rtx
4682ae04 2159adjust_offset_for_component_ref (tree x, rtx offset)
998d7deb
RH
2160{
2161 HOST_WIDE_INT ioffset;
2162
2163 if (! offset)
2164 return NULL_RTX;
2165
2166 ioffset = INTVAL (offset);
ca7fd9cd 2167 do
998d7deb 2168 {
44de5aeb 2169 tree offset = component_ref_field_offset (x);
998d7deb
RH
2170 tree field = TREE_OPERAND (x, 1);
2171
44de5aeb 2172 if (! host_integerp (offset, 1))
998d7deb 2173 return NULL_RTX;
44de5aeb 2174 ioffset += (tree_low_cst (offset, 1)
998d7deb
RH
2175 + (tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1)
2176 / BITS_PER_UNIT));
2177
2178 x = TREE_OPERAND (x, 0);
2179 }
2180 while (x && TREE_CODE (x) == COMPONENT_REF);
2181
2182 return GEN_INT (ioffset);
2183}
2184
95bd1dd7 2185/* Return nonzero if we can determine the exprs corresponding to memrefs
a4311dfe
RK
2186 X and Y and they do not overlap. */
2187
2e4e39f6 2188int
4f588890 2189nonoverlapping_memrefs_p (const_rtx x, const_rtx y)
a4311dfe 2190{
998d7deb 2191 tree exprx = MEM_EXPR (x), expry = MEM_EXPR (y);
a4311dfe
RK
2192 rtx rtlx, rtly;
2193 rtx basex, basey;
998d7deb 2194 rtx moffsetx, moffsety;
a4311dfe
RK
2195 HOST_WIDE_INT offsetx = 0, offsety = 0, sizex, sizey, tem;
2196
998d7deb
RH
2197 /* Unless both have exprs, we can't tell anything. */
2198 if (exprx == 0 || expry == 0)
2199 return 0;
2b22e382
RG
2200
2201 /* For spill-slot accesses make sure we have valid offsets. */
2202 if ((exprx == get_spill_slot_decl (false)
2203 && ! MEM_OFFSET (x))
2204 || (expry == get_spill_slot_decl (false)
2205 && ! MEM_OFFSET (y)))
2206 return 0;
c22cacf3 2207
998d7deb
RH
2208 /* If both are field references, we may be able to determine something. */
2209 if (TREE_CODE (exprx) == COMPONENT_REF
2210 && TREE_CODE (expry) == COMPONENT_REF
2211 && nonoverlapping_component_refs_p (exprx, expry))
2212 return 1;
2213
c22cacf3 2214
998d7deb
RH
2215 /* If the field reference test failed, look at the DECLs involved. */
2216 moffsetx = MEM_OFFSET (x);
2217 if (TREE_CODE (exprx) == COMPONENT_REF)
2218 {
2e0c984c
RG
2219 tree t = decl_for_component_ref (exprx);
2220 if (! t)
2221 return 0;
2222 moffsetx = adjust_offset_for_component_ref (exprx, moffsetx);
2223 exprx = t;
998d7deb 2224 }
c67a1cf6 2225
998d7deb
RH
2226 moffsety = MEM_OFFSET (y);
2227 if (TREE_CODE (expry) == COMPONENT_REF)
2228 {
2e0c984c
RG
2229 tree t = decl_for_component_ref (expry);
2230 if (! t)
2231 return 0;
2232 moffsety = adjust_offset_for_component_ref (expry, moffsety);
2233 expry = t;
998d7deb
RH
2234 }
2235
2236 if (! DECL_P (exprx) || ! DECL_P (expry))
a4311dfe
RK
2237 return 0;
2238
1307c758
RG
2239 /* With invalid code we can end up storing into the constant pool.
2240 Bail out to avoid ICEing when creating RTL for this.
2241 See gfortran.dg/lto/20091028-2_0.f90. */
2242 if (TREE_CODE (exprx) == CONST_DECL
2243 || TREE_CODE (expry) == CONST_DECL)
2244 return 1;
2245
998d7deb
RH
2246 rtlx = DECL_RTL (exprx);
2247 rtly = DECL_RTL (expry);
a4311dfe 2248
1edcd60b
RK
2249 /* If either RTL is not a MEM, it must be a REG or CONCAT, meaning they
2250 can't overlap unless they are the same because we never reuse that part
2251 of the stack frame used for locals for spilled pseudos. */
3c0cb5de 2252 if ((!MEM_P (rtlx) || !MEM_P (rtly))
1edcd60b 2253 && ! rtx_equal_p (rtlx, rtly))
a4311dfe
RK
2254 return 1;
2255
09e881c9
BE
2256 /* If we have MEMs refering to different address spaces (which can
2257 potentially overlap), we cannot easily tell from the addresses
2258 whether the references overlap. */
2259 if (MEM_P (rtlx) && MEM_P (rtly)
2260 && MEM_ADDR_SPACE (rtlx) != MEM_ADDR_SPACE (rtly))
2261 return 0;
2262
a4311dfe
RK
2263 /* Get the base and offsets of both decls. If either is a register, we
2264 know both are and are the same, so use that as the base. The only
2265 we can avoid overlap is if we can deduce that they are nonoverlapping
2266 pieces of that decl, which is very rare. */
3c0cb5de 2267 basex = MEM_P (rtlx) ? XEXP (rtlx, 0) : rtlx;
481683e1 2268 if (GET_CODE (basex) == PLUS && CONST_INT_P (XEXP (basex, 1)))
a4311dfe
RK
2269 offsetx = INTVAL (XEXP (basex, 1)), basex = XEXP (basex, 0);
2270
3c0cb5de 2271 basey = MEM_P (rtly) ? XEXP (rtly, 0) : rtly;
481683e1 2272 if (GET_CODE (basey) == PLUS && CONST_INT_P (XEXP (basey, 1)))
a4311dfe
RK
2273 offsety = INTVAL (XEXP (basey, 1)), basey = XEXP (basey, 0);
2274
d746694a 2275 /* If the bases are different, we know they do not overlap if both
ca7fd9cd 2276 are constants or if one is a constant and the other a pointer into the
d746694a
RK
2277 stack frame. Otherwise a different base means we can't tell if they
2278 overlap or not. */
2279 if (! rtx_equal_p (basex, basey))
ca7fd9cd
KH
2280 return ((CONSTANT_P (basex) && CONSTANT_P (basey))
2281 || (CONSTANT_P (basex) && REG_P (basey)
2282 && REGNO_PTR_FRAME_P (REGNO (basey)))
2283 || (CONSTANT_P (basey) && REG_P (basex)
2284 && REGNO_PTR_FRAME_P (REGNO (basex))));
a4311dfe 2285
3c0cb5de 2286 sizex = (!MEM_P (rtlx) ? (int) GET_MODE_SIZE (GET_MODE (rtlx))
a4311dfe
RK
2287 : MEM_SIZE (rtlx) ? INTVAL (MEM_SIZE (rtlx))
2288 : -1);
3c0cb5de 2289 sizey = (!MEM_P (rtly) ? (int) GET_MODE_SIZE (GET_MODE (rtly))
a4311dfe
RK
2290 : MEM_SIZE (rtly) ? INTVAL (MEM_SIZE (rtly)) :
2291 -1);
2292
0af5bc3e
RK
2293 /* If we have an offset for either memref, it can update the values computed
2294 above. */
998d7deb
RH
2295 if (moffsetx)
2296 offsetx += INTVAL (moffsetx), sizex -= INTVAL (moffsetx);
2297 if (moffsety)
2298 offsety += INTVAL (moffsety), sizey -= INTVAL (moffsety);
a4311dfe 2299
0af5bc3e 2300 /* If a memref has both a size and an offset, we can use the smaller size.
efc981bb 2301 We can't do this if the offset isn't known because we must view this
0af5bc3e 2302 memref as being anywhere inside the DECL's MEM. */
998d7deb 2303 if (MEM_SIZE (x) && moffsetx)
a4311dfe 2304 sizex = INTVAL (MEM_SIZE (x));
998d7deb 2305 if (MEM_SIZE (y) && moffsety)
a4311dfe
RK
2306 sizey = INTVAL (MEM_SIZE (y));
2307
2308 /* Put the values of the memref with the lower offset in X's values. */
2309 if (offsetx > offsety)
2310 {
2311 tem = offsetx, offsetx = offsety, offsety = tem;
2312 tem = sizex, sizex = sizey, sizey = tem;
2313 }
2314
2315 /* If we don't know the size of the lower-offset value, we can't tell
2316 if they conflict. Otherwise, we do the test. */
a6f7c915 2317 return sizex >= 0 && offsety >= offsetx + sizex;
a4311dfe
RK
2318}
2319
9ae8ffe7
JL
2320/* True dependence: X is read after store in MEM takes place. */
2321
2322int
4f588890
KG
2323true_dependence (const_rtx mem, enum machine_mode mem_mode, const_rtx x,
2324 bool (*varies) (const_rtx, bool))
9ae8ffe7 2325{
b3694847 2326 rtx x_addr, mem_addr;
49982682 2327 rtx base;
f47e08d9 2328 int ret;
9ae8ffe7
JL
2329
2330 if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem))
2331 return 1;
2332
c4484b8f 2333 /* (mem:BLK (scratch)) is a special mechanism to conflict with everything.
ac3768f6 2334 This is used in epilogue deallocation functions, and in cselib. */
c4484b8f
RH
2335 if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH)
2336 return 1;
2337 if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH)
2338 return 1;
9cd9e512
RH
2339 if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER
2340 || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER)
2341 return 1;
c4484b8f 2342
389fdba0
RH
2343 /* Read-only memory is by definition never modified, and therefore can't
2344 conflict with anything. We don't expect to find read-only set on MEM,
41806d92 2345 but stupid user tricks can produce them, so don't die. */
389fdba0 2346 if (MEM_READONLY_P (x))
9ae8ffe7
JL
2347 return 0;
2348
09e881c9
BE
2349 /* If we have MEMs refering to different address spaces (which can
2350 potentially overlap), we cannot easily tell from the addresses
2351 whether the references overlap. */
2352 if (MEM_ADDR_SPACE (mem) != MEM_ADDR_SPACE (x))
2353 return 1;
2354
56ee9281
RH
2355 if (mem_mode == VOIDmode)
2356 mem_mode = GET_MODE (mem);
2357
2147c71c
L
2358 x_addr = XEXP (x, 0);
2359 mem_addr = XEXP (mem, 0);
2360 if (!((GET_CODE (x_addr) == VALUE
2361 && GET_CODE (mem_addr) != VALUE
2362 && reg_mentioned_p (x_addr, mem_addr))
2363 || (GET_CODE (x_addr) != VALUE
2364 && GET_CODE (mem_addr) == VALUE
2365 && reg_mentioned_p (mem_addr, x_addr))))
2366 {
2367 x_addr = get_addr (x_addr);
2368 mem_addr = get_addr (mem_addr);
2369 }
eab5c70a 2370
55efb413
JW
2371 base = find_base_term (x_addr);
2372 if (base && (GET_CODE (base) == LABEL_REF
2373 || (GET_CODE (base) == SYMBOL_REF
2374 && CONSTANT_POOL_ADDRESS_P (base))))
2375 return 0;
2376
eab5c70a 2377 if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), mem_mode))
1c72c7f6
JC
2378 return 0;
2379
eab5c70a
BS
2380 x_addr = canon_rtx (x_addr);
2381 mem_addr = canon_rtx (mem_addr);
6e73e666 2382
f47e08d9
RG
2383 if ((ret = memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr,
2384 SIZE_FOR_MODE (x), x_addr, 0)) != -1)
2385 return ret;
2386
2387 if (DIFFERENT_ALIAS_SETS_P (x, mem))
2388 return 0;
2389
2390 if (nonoverlapping_memrefs_p (mem, x))
0211b6ab
JW
2391 return 0;
2392
c6df88cb 2393 if (aliases_everything_p (x))
0211b6ab
JW
2394 return 1;
2395
f5143c46 2396 /* We cannot use aliases_everything_p to test MEM, since we must look
c6df88cb
MM
2397 at MEM_MODE, rather than GET_MODE (MEM). */
2398 if (mem_mode == QImode || GET_CODE (mem_addr) == AND)
a13d4ebf
AM
2399 return 1;
2400
2401 /* In true_dependence we also allow BLKmode to alias anything. Why
2402 don't we do this in anti_dependence and output_dependence? */
2403 if (mem_mode == BLKmode || GET_MODE (x) == BLKmode)
2404 return 1;
2405
55b34b5f
RG
2406 if (fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, varies))
2407 return 0;
2408
2409 return rtx_refs_may_alias_p (x, mem, true);
a13d4ebf
AM
2410}
2411
2412/* Canonical true dependence: X is read after store in MEM takes place.
ca7fd9cd
KH
2413 Variant of true_dependence which assumes MEM has already been
2414 canonicalized (hence we no longer do that here).
2415 The mem_addr argument has been added, since true_dependence computed
6216f94e
JJ
2416 this value prior to canonicalizing.
2417 If x_addr is non-NULL, it is used in preference of XEXP (x, 0). */
a13d4ebf
AM
2418
2419int
4f588890 2420canon_true_dependence (const_rtx mem, enum machine_mode mem_mode, rtx mem_addr,
6216f94e 2421 const_rtx x, rtx x_addr, bool (*varies) (const_rtx, bool))
a13d4ebf 2422{
f47e08d9
RG
2423 int ret;
2424
a13d4ebf
AM
2425 if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem))
2426 return 1;
2427
0fe854a7
RH
2428 /* (mem:BLK (scratch)) is a special mechanism to conflict with everything.
2429 This is used in epilogue deallocation functions. */
2430 if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH)
2431 return 1;
2432 if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH)
2433 return 1;
9cd9e512
RH
2434 if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER
2435 || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER)
2436 return 1;
0fe854a7 2437
389fdba0
RH
2438 /* Read-only memory is by definition never modified, and therefore can't
2439 conflict with anything. We don't expect to find read-only set on MEM,
41806d92 2440 but stupid user tricks can produce them, so don't die. */
389fdba0 2441 if (MEM_READONLY_P (x))
a13d4ebf
AM
2442 return 0;
2443
09e881c9
BE
2444 /* If we have MEMs refering to different address spaces (which can
2445 potentially overlap), we cannot easily tell from the addresses
2446 whether the references overlap. */
2447 if (MEM_ADDR_SPACE (mem) != MEM_ADDR_SPACE (x))
2448 return 1;
2449
6216f94e 2450 if (! x_addr)
2147c71c
L
2451 {
2452 x_addr = XEXP (x, 0);
2453 if (!((GET_CODE (x_addr) == VALUE
2454 && GET_CODE (mem_addr) != VALUE
2455 && reg_mentioned_p (x_addr, mem_addr))
2456 || (GET_CODE (x_addr) != VALUE
2457 && GET_CODE (mem_addr) == VALUE
2458 && reg_mentioned_p (mem_addr, x_addr))))
2459 x_addr = get_addr (x_addr);
2460 }
a13d4ebf
AM
2461
2462 if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), mem_mode))
2463 return 0;
2464
2465 x_addr = canon_rtx (x_addr);
f47e08d9
RG
2466 if ((ret = memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr,
2467 SIZE_FOR_MODE (x), x_addr, 0)) != -1)
2468 return ret;
2469
2470 if (DIFFERENT_ALIAS_SETS_P (x, mem))
2471 return 0;
2472
2473 if (nonoverlapping_memrefs_p (x, mem))
a13d4ebf
AM
2474 return 0;
2475
2476 if (aliases_everything_p (x))
2477 return 1;
2478
f5143c46 2479 /* We cannot use aliases_everything_p to test MEM, since we must look
a13d4ebf
AM
2480 at MEM_MODE, rather than GET_MODE (MEM). */
2481 if (mem_mode == QImode || GET_CODE (mem_addr) == AND)
c6df88cb 2482 return 1;
0211b6ab 2483
c6df88cb
MM
2484 /* In true_dependence we also allow BLKmode to alias anything. Why
2485 don't we do this in anti_dependence and output_dependence? */
2486 if (mem_mode == BLKmode || GET_MODE (x) == BLKmode)
2487 return 1;
0211b6ab 2488
55b34b5f
RG
2489 if (fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, varies))
2490 return 0;
2491
2492 return rtx_refs_may_alias_p (x, mem, true);
9ae8ffe7
JL
2493}
2494
da7d8304 2495/* Returns nonzero if a write to X might alias a previous read from
389fdba0 2496 (or, if WRITEP is nonzero, a write to) MEM. */
9ae8ffe7 2497
2c72b78f 2498static int
4f588890 2499write_dependence_p (const_rtx mem, const_rtx x, int writep)
9ae8ffe7 2500{
6e73e666 2501 rtx x_addr, mem_addr;
4f588890 2502 const_rtx fixed_scalar;
49982682 2503 rtx base;
f47e08d9 2504 int ret;
6e73e666 2505
9ae8ffe7
JL
2506 if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem))
2507 return 1;
2508
c4484b8f
RH
2509 /* (mem:BLK (scratch)) is a special mechanism to conflict with everything.
2510 This is used in epilogue deallocation functions. */
2511 if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH)
2512 return 1;
2513 if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH)
2514 return 1;
9cd9e512
RH
2515 if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER
2516 || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER)
2517 return 1;
c4484b8f 2518
389fdba0
RH
2519 /* A read from read-only memory can't conflict with read-write memory. */
2520 if (!writep && MEM_READONLY_P (mem))
2521 return 0;
55efb413 2522
09e881c9
BE
2523 /* If we have MEMs refering to different address spaces (which can
2524 potentially overlap), we cannot easily tell from the addresses
2525 whether the references overlap. */
2526 if (MEM_ADDR_SPACE (mem) != MEM_ADDR_SPACE (x))
2527 return 1;
2528
2147c71c
L
2529 x_addr = XEXP (x, 0);
2530 mem_addr = XEXP (mem, 0);
2531 if (!((GET_CODE (x_addr) == VALUE
2532 && GET_CODE (mem_addr) != VALUE
2533 && reg_mentioned_p (x_addr, mem_addr))
2534 || (GET_CODE (x_addr) != VALUE
2535 && GET_CODE (mem_addr) == VALUE
2536 && reg_mentioned_p (mem_addr, x_addr))))
2537 {
2538 x_addr = get_addr (x_addr);
2539 mem_addr = get_addr (mem_addr);
2540 }
55efb413 2541
49982682
JW
2542 if (! writep)
2543 {
55efb413 2544 base = find_base_term (mem_addr);
49982682
JW
2545 if (base && (GET_CODE (base) == LABEL_REF
2546 || (GET_CODE (base) == SYMBOL_REF
2547 && CONSTANT_POOL_ADDRESS_P (base))))
2548 return 0;
2549 }
2550
eab5c70a
BS
2551 if (! base_alias_check (x_addr, mem_addr, GET_MODE (x),
2552 GET_MODE (mem)))
41472af8
MM
2553 return 0;
2554
eab5c70a
BS
2555 x_addr = canon_rtx (x_addr);
2556 mem_addr = canon_rtx (mem_addr);
6e73e666 2557
f47e08d9
RG
2558 if ((ret = memrefs_conflict_p (SIZE_FOR_MODE (mem), mem_addr,
2559 SIZE_FOR_MODE (x), x_addr, 0)) != -1)
2560 return ret;
2561
2562 if (nonoverlapping_memrefs_p (x, mem))
c6df88cb
MM
2563 return 0;
2564
ca7fd9cd 2565 fixed_scalar
eab5c70a
BS
2566 = fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr,
2567 rtx_addr_varies_p);
2568
55b34b5f
RG
2569 if ((fixed_scalar == mem && !aliases_everything_p (x))
2570 || (fixed_scalar == x && !aliases_everything_p (mem)))
2571 return 0;
2572
2573 return rtx_refs_may_alias_p (x, mem, false);
c6df88cb
MM
2574}
2575
2576/* Anti dependence: X is written after read in MEM takes place. */
2577
2578int
4f588890 2579anti_dependence (const_rtx mem, const_rtx x)
c6df88cb 2580{
389fdba0 2581 return write_dependence_p (mem, x, /*writep=*/0);
9ae8ffe7
JL
2582}
2583
2584/* Output dependence: X is written after store in MEM takes place. */
2585
2586int
4f588890 2587output_dependence (const_rtx mem, const_rtx x)
9ae8ffe7 2588{
389fdba0 2589 return write_dependence_p (mem, x, /*writep=*/1);
9ae8ffe7 2590}
c14b9960 2591\f
6e73e666 2592
6e73e666 2593void
b5deb7b6 2594init_alias_target (void)
6e73e666 2595{
b3694847 2596 int i;
6e73e666 2597
b5deb7b6
SL
2598 memset (static_reg_base_value, 0, sizeof static_reg_base_value);
2599
6e73e666
JC
2600 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
2601 /* Check whether this register can hold an incoming pointer
2602 argument. FUNCTION_ARG_REGNO_P tests outgoing register
ec5c56db 2603 numbers, so translate if necessary due to register windows. */
6e73e666
JC
2604 if (FUNCTION_ARG_REGNO_P (OUTGOING_REGNO (i))
2605 && HARD_REGNO_MODE_OK (i, Pmode))
bf1660a6
JL
2606 static_reg_base_value[i]
2607 = gen_rtx_ADDRESS (VOIDmode, gen_rtx_REG (Pmode, i));
2608
bf1660a6
JL
2609 static_reg_base_value[STACK_POINTER_REGNUM]
2610 = gen_rtx_ADDRESS (Pmode, stack_pointer_rtx);
2611 static_reg_base_value[ARG_POINTER_REGNUM]
2612 = gen_rtx_ADDRESS (Pmode, arg_pointer_rtx);
2613 static_reg_base_value[FRAME_POINTER_REGNUM]
2614 = gen_rtx_ADDRESS (Pmode, frame_pointer_rtx);
2615#if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM
2616 static_reg_base_value[HARD_FRAME_POINTER_REGNUM]
2617 = gen_rtx_ADDRESS (Pmode, hard_frame_pointer_rtx);
2618#endif
2619}
2620
7b52eede
JH
2621/* Set MEMORY_MODIFIED when X modifies DATA (that is assumed
2622 to be memory reference. */
2623static bool memory_modified;
2624static void
aa317c97 2625memory_modified_1 (rtx x, const_rtx pat ATTRIBUTE_UNUSED, void *data)
7b52eede 2626{
3c0cb5de 2627 if (MEM_P (x))
7b52eede 2628 {
9678086d 2629 if (anti_dependence (x, (const_rtx)data) || output_dependence (x, (const_rtx)data))
7b52eede
JH
2630 memory_modified = true;
2631 }
2632}
2633
2634
2635/* Return true when INSN possibly modify memory contents of MEM
454ff5cb 2636 (i.e. address can be modified). */
7b52eede 2637bool
9678086d 2638memory_modified_in_insn_p (const_rtx mem, const_rtx insn)
7b52eede
JH
2639{
2640 if (!INSN_P (insn))
2641 return false;
2642 memory_modified = false;
aa317c97 2643 note_stores (PATTERN (insn), memory_modified_1, CONST_CAST_RTX(mem));
7b52eede
JH
2644 return memory_modified;
2645}
2646
c13e8210
MM
2647/* Initialize the aliasing machinery. Initialize the REG_KNOWN_VALUE
2648 array. */
2649
9ae8ffe7 2650void
4682ae04 2651init_alias_analysis (void)
9ae8ffe7 2652{
c582d54a 2653 unsigned int maxreg = max_reg_num ();
ea64ef27 2654 int changed, pass;
b3694847
SS
2655 int i;
2656 unsigned int ui;
2657 rtx insn;
9ae8ffe7 2658
0d446150
JH
2659 timevar_push (TV_ALIAS_ANALYSIS);
2660
bb1acb3e 2661 reg_known_value_size = maxreg - FIRST_PSEUDO_REGISTER;
a9429e29 2662 reg_known_value = ggc_alloc_cleared_vec_rtx (reg_known_value_size);
f883e0a7 2663 reg_known_equiv_p = XCNEWVEC (bool, reg_known_value_size);
9ae8ffe7 2664
08c79682 2665 /* If we have memory allocated from the previous run, use it. */
c582d54a 2666 if (old_reg_base_value)
08c79682
KH
2667 reg_base_value = old_reg_base_value;
2668
2669 if (reg_base_value)
2670 VEC_truncate (rtx, reg_base_value, 0);
2671
a590ac65 2672 VEC_safe_grow_cleared (rtx, gc, reg_base_value, maxreg);
ac606739 2673
5ed6ace5
MD
2674 new_reg_base_value = XNEWVEC (rtx, maxreg);
2675 reg_seen = XNEWVEC (char, maxreg);
ec907dd8
JL
2676
2677 /* The basic idea is that each pass through this loop will use the
2678 "constant" information from the previous pass to propagate alias
2679 information through another level of assignments.
2680
2681 This could get expensive if the assignment chains are long. Maybe
2682 we should throttle the number of iterations, possibly based on
6e73e666 2683 the optimization level or flag_expensive_optimizations.
ec907dd8
JL
2684
2685 We could propagate more information in the first pass by making use
6fb5fa3c 2686 of DF_REG_DEF_COUNT to determine immediately that the alias information
ea64ef27
JL
2687 for a pseudo is "constant".
2688
2689 A program with an uninitialized variable can cause an infinite loop
2690 here. Instead of doing a full dataflow analysis to detect such problems
2691 we just cap the number of iterations for the loop.
2692
2693 The state of the arrays for the set chain in question does not matter
2694 since the program has undefined behavior. */
6e73e666 2695
ea64ef27 2696 pass = 0;
6e73e666 2697 do
ec907dd8
JL
2698 {
2699 /* Assume nothing will change this iteration of the loop. */
2700 changed = 0;
2701
ec907dd8
JL
2702 /* We want to assign the same IDs each iteration of this loop, so
2703 start counting from zero each iteration of the loop. */
2704 unique_id = 0;
2705
f5143c46 2706 /* We're at the start of the function each iteration through the
ec907dd8 2707 loop, so we're copying arguments. */
83bbd9b6 2708 copying_arguments = true;
9ae8ffe7 2709
6e73e666 2710 /* Wipe the potential alias information clean for this pass. */
c582d54a 2711 memset (new_reg_base_value, 0, maxreg * sizeof (rtx));
8072f69c 2712
6e73e666 2713 /* Wipe the reg_seen array clean. */
c582d54a 2714 memset (reg_seen, 0, maxreg);
9ae8ffe7 2715
6e73e666
JC
2716 /* Mark all hard registers which may contain an address.
2717 The stack, frame and argument pointers may contain an address.
2718 An argument register which can hold a Pmode value may contain
2719 an address even if it is not in BASE_REGS.
8072f69c 2720
6e73e666
JC
2721 The address expression is VOIDmode for an argument and
2722 Pmode for other registers. */
2723
7f243674
JL
2724 memcpy (new_reg_base_value, static_reg_base_value,
2725 FIRST_PSEUDO_REGISTER * sizeof (rtx));
6e73e666 2726
ec907dd8
JL
2727 /* Walk the insns adding values to the new_reg_base_value array. */
2728 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
9ae8ffe7 2729 {
2c3c49de 2730 if (INSN_P (insn))
ec907dd8 2731 {
6e73e666 2732 rtx note, set;
efc9bd41
RK
2733
2734#if defined (HAVE_prologue) || defined (HAVE_epilogue)
f5143c46 2735 /* The prologue/epilogue insns are not threaded onto the
657959ca
JL
2736 insn chain until after reload has completed. Thus,
2737 there is no sense wasting time checking if INSN is in
2738 the prologue/epilogue until after reload has completed. */
2739 if (reload_completed
2740 && prologue_epilogue_contains (insn))
efc9bd41
RK
2741 continue;
2742#endif
2743
ec907dd8 2744 /* If this insn has a noalias note, process it, Otherwise,
c22cacf3
MS
2745 scan for sets. A simple set will have no side effects
2746 which could change the base value of any other register. */
6e73e666 2747
ec907dd8 2748 if (GET_CODE (PATTERN (insn)) == SET
efc9bd41
RK
2749 && REG_NOTES (insn) != 0
2750 && find_reg_note (insn, REG_NOALIAS, NULL_RTX))
84832317 2751 record_set (SET_DEST (PATTERN (insn)), NULL_RTX, NULL);
ec907dd8 2752 else
84832317 2753 note_stores (PATTERN (insn), record_set, NULL);
6e73e666
JC
2754
2755 set = single_set (insn);
2756
2757 if (set != 0
f8cfc6aa 2758 && REG_P (SET_DEST (set))
fb6754f0 2759 && REGNO (SET_DEST (set)) >= FIRST_PSEUDO_REGISTER)
6e73e666 2760 {
fb6754f0 2761 unsigned int regno = REGNO (SET_DEST (set));
713f41f9 2762 rtx src = SET_SRC (set);
bb1acb3e 2763 rtx t;
713f41f9 2764
a31830a7
SB
2765 note = find_reg_equal_equiv_note (insn);
2766 if (note && REG_NOTE_KIND (note) == REG_EQUAL
6fb5fa3c 2767 && DF_REG_DEF_COUNT (regno) != 1)
a31830a7
SB
2768 note = NULL_RTX;
2769
2770 if (note != NULL_RTX
713f41f9 2771 && GET_CODE (XEXP (note, 0)) != EXPR_LIST
bb2cf916 2772 && ! rtx_varies_p (XEXP (note, 0), 1)
bb1acb3e
RH
2773 && ! reg_overlap_mentioned_p (SET_DEST (set),
2774 XEXP (note, 0)))
713f41f9 2775 {
bb1acb3e
RH
2776 set_reg_known_value (regno, XEXP (note, 0));
2777 set_reg_known_equiv_p (regno,
2778 REG_NOTE_KIND (note) == REG_EQUIV);
713f41f9 2779 }
6fb5fa3c 2780 else if (DF_REG_DEF_COUNT (regno) == 1
713f41f9 2781 && GET_CODE (src) == PLUS
f8cfc6aa 2782 && REG_P (XEXP (src, 0))
bb1acb3e 2783 && (t = get_reg_known_value (REGNO (XEXP (src, 0))))
481683e1 2784 && CONST_INT_P (XEXP (src, 1)))
713f41f9 2785 {
bb1acb3e
RH
2786 t = plus_constant (t, INTVAL (XEXP (src, 1)));
2787 set_reg_known_value (regno, t);
2788 set_reg_known_equiv_p (regno, 0);
713f41f9 2789 }
6fb5fa3c 2790 else if (DF_REG_DEF_COUNT (regno) == 1
713f41f9
BS
2791 && ! rtx_varies_p (src, 1))
2792 {
bb1acb3e
RH
2793 set_reg_known_value (regno, src);
2794 set_reg_known_equiv_p (regno, 0);
713f41f9 2795 }
6e73e666 2796 }
ec907dd8 2797 }
4b4bf941 2798 else if (NOTE_P (insn)
a38e7aa5 2799 && NOTE_KIND (insn) == NOTE_INSN_FUNCTION_BEG)
83bbd9b6 2800 copying_arguments = false;
6e73e666 2801 }
ec907dd8 2802
6e73e666 2803 /* Now propagate values from new_reg_base_value to reg_base_value. */
62e5bf5d 2804 gcc_assert (maxreg == (unsigned int) max_reg_num ());
c22cacf3 2805
c582d54a 2806 for (ui = 0; ui < maxreg; ui++)
6e73e666 2807 {
e51712db 2808 if (new_reg_base_value[ui]
08c79682 2809 && new_reg_base_value[ui] != VEC_index (rtx, reg_base_value, ui)
c582d54a 2810 && ! rtx_equal_p (new_reg_base_value[ui],
08c79682 2811 VEC_index (rtx, reg_base_value, ui)))
ec907dd8 2812 {
08c79682 2813 VEC_replace (rtx, reg_base_value, ui, new_reg_base_value[ui]);
6e73e666 2814 changed = 1;
ec907dd8 2815 }
9ae8ffe7 2816 }
9ae8ffe7 2817 }
6e73e666 2818 while (changed && ++pass < MAX_ALIAS_LOOP_PASSES);
9ae8ffe7
JL
2819
2820 /* Fill in the remaining entries. */
bb1acb3e 2821 for (i = 0; i < (int)reg_known_value_size; i++)
9ae8ffe7 2822 if (reg_known_value[i] == 0)
bb1acb3e 2823 reg_known_value[i] = regno_reg_rtx[i + FIRST_PSEUDO_REGISTER];
9ae8ffe7 2824
e05e2395
MM
2825 /* Clean up. */
2826 free (new_reg_base_value);
ec907dd8 2827 new_reg_base_value = 0;
e05e2395 2828 free (reg_seen);
9ae8ffe7 2829 reg_seen = 0;
0d446150 2830 timevar_pop (TV_ALIAS_ANALYSIS);
9ae8ffe7
JL
2831}
2832
2833void
4682ae04 2834end_alias_analysis (void)
9ae8ffe7 2835{
c582d54a 2836 old_reg_base_value = reg_base_value;
bb1acb3e 2837 ggc_free (reg_known_value);
9ae8ffe7 2838 reg_known_value = 0;
ac606739 2839 reg_known_value_size = 0;
bb1acb3e 2840 free (reg_known_equiv_p);
e05e2395 2841 reg_known_equiv_p = 0;
9ae8ffe7 2842}
e2500fed
GK
2843
2844#include "gt-alias.h"