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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, |
66647d44 | 3 | 2007, 2008, 2009 Free Software Foundation, Inc. |
9ae8ffe7 JL |
4 | Contributed by John Carr (jfc@mit.edu). |
5 | ||
1322177d | 6 | This file is part of GCC. |
9ae8ffe7 | 7 | |
1322177d LB |
8 | GCC is free software; you can redistribute it and/or modify it under |
9 | the terms of the GNU General Public License as published by the Free | |
9dcd6f09 | 10 | Software Foundation; either version 3, or (at your option) any later |
1322177d | 11 | version. |
9ae8ffe7 | 12 | |
1322177d LB |
13 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY |
14 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
15 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
16 | for more details. | |
9ae8ffe7 JL |
17 | |
18 | You should have received a copy of the GNU General Public License | |
9dcd6f09 NC |
19 | along 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" |
2e107e9e | 37 | #include "toplev.h" |
eab5c70a | 38 | #include "cselib.h" |
3932261a | 39 | #include "splay-tree.h" |
ac606739 | 40 | #include "ggc.h" |
d23c55c2 | 41 | #include "langhooks.h" |
0d446150 | 42 | #include "timevar.h" |
ab780373 | 43 | #include "target.h" |
b255a036 | 44 | #include "cgraph.h" |
9ddb66ca | 45 | #include "varray.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 | 134 | struct 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 | 151 | typedef struct alias_set_entry_d *alias_set_entry; |
9ae8ffe7 | 152 | |
ed7a4b4b | 153 | static int rtx_equal_for_memref_p (const_rtx, const_rtx); |
4682ae04 | 154 | static int memrefs_conflict_p (int, rtx, int, rtx, HOST_WIDE_INT); |
7bc980e1 | 155 | static void record_set (rtx, const_rtx, void *); |
4682ae04 AJ |
156 | static int base_alias_check (rtx, rtx, enum machine_mode, |
157 | enum machine_mode); | |
158 | static rtx find_base_value (rtx); | |
4f588890 | 159 | static int mems_in_disjoint_alias_sets_p (const_rtx, const_rtx); |
4682ae04 | 160 | static int insert_subset_children (splay_tree_node, void*); |
4862826d | 161 | static alias_set_entry get_alias_set_entry (alias_set_type); |
4f588890 KG |
162 | static const_rtx fixed_scalar_and_varying_struct_p (const_rtx, const_rtx, rtx, rtx, |
163 | bool (*) (const_rtx, bool)); | |
164 | static int aliases_everything_p (const_rtx); | |
165 | static bool nonoverlapping_component_refs_p (const_tree, const_tree); | |
4682ae04 AJ |
166 | static tree decl_for_component_ref (tree); |
167 | static rtx adjust_offset_for_component_ref (tree, rtx); | |
4f588890 | 168 | static int write_dependence_p (const_rtx, const_rtx, int); |
4682ae04 | 169 | |
aa317c97 | 170 | static 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 | 207 | static GTY(()) VEC(rtx,gc) *reg_base_value; |
ac606739 | 208 | static 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 | 213 | static GTY((deletable)) VEC(rtx,gc) *old_reg_base_value; |
d4b60170 | 214 | |
bf1660a6 JL |
215 | /* Static hunks of RTL used by the aliasing code; these are initialized |
216 | once per function to avoid unnecessary RTL allocations. */ | |
217 | static GTY (()) rtx static_reg_base_value[FIRST_PSEUDO_REGISTER]; | |
218 | ||
08c79682 KH |
219 | #define REG_BASE_VALUE(X) \ |
220 | (REGNO (X) < VEC_length (rtx, reg_base_value) \ | |
221 | ? VEC_index (rtx, reg_base_value, REGNO (X)) : 0) | |
9ae8ffe7 | 222 | |
c13e8210 | 223 | /* Vector indexed by N giving the initial (unchanging) value known for |
bb1acb3e RH |
224 | pseudo-register N. This array is initialized in init_alias_analysis, |
225 | and does not change until end_alias_analysis is called. */ | |
226 | static GTY((length("reg_known_value_size"))) rtx *reg_known_value; | |
9ae8ffe7 JL |
227 | |
228 | /* Indicates number of valid entries in reg_known_value. */ | |
bb1acb3e | 229 | static GTY(()) unsigned int reg_known_value_size; |
9ae8ffe7 JL |
230 | |
231 | /* Vector recording for each reg_known_value whether it is due to a | |
232 | REG_EQUIV note. Future passes (viz., reload) may replace the | |
233 | pseudo with the equivalent expression and so we account for the | |
ac3d9668 RK |
234 | dependences that would be introduced if that happens. |
235 | ||
236 | The REG_EQUIV notes created in assign_parms may mention the arg | |
237 | pointer, and there are explicit insns in the RTL that modify the | |
238 | arg pointer. Thus we must ensure that such insns don't get | |
239 | scheduled across each other because that would invalidate the | |
240 | REG_EQUIV notes. One could argue that the REG_EQUIV notes are | |
241 | wrong, but solving the problem in the scheduler will likely give | |
242 | better code, so we do it here. */ | |
bb1acb3e | 243 | static bool *reg_known_equiv_p; |
9ae8ffe7 | 244 | |
2a2c8203 JC |
245 | /* True when scanning insns from the start of the rtl to the |
246 | NOTE_INSN_FUNCTION_BEG note. */ | |
83bbd9b6 | 247 | static bool copying_arguments; |
9ae8ffe7 | 248 | |
1a5640b4 KH |
249 | DEF_VEC_P(alias_set_entry); |
250 | DEF_VEC_ALLOC_P(alias_set_entry,gc); | |
251 | ||
3932261a | 252 | /* The splay-tree used to store the various alias set entries. */ |
1a5640b4 | 253 | static GTY (()) VEC(alias_set_entry,gc) *alias_sets; |
ac3d9668 | 254 | \f |
55b34b5f RG |
255 | /* Build a decomposed reference object for querying the alias-oracle |
256 | from the MEM rtx and store it in *REF. | |
257 | Returns false if MEM is not suitable for the alias-oracle. */ | |
258 | ||
259 | static bool | |
260 | ao_ref_from_mem (ao_ref *ref, const_rtx mem) | |
261 | { | |
262 | tree expr = MEM_EXPR (mem); | |
263 | tree base; | |
264 | ||
265 | if (!expr) | |
266 | return false; | |
267 | ||
268 | ao_ref_init (ref, expr); | |
269 | ||
270 | /* Get the base of the reference and see if we have to reject or | |
271 | adjust it. */ | |
272 | base = ao_ref_base (ref); | |
273 | if (base == NULL_TREE) | |
274 | return false; | |
275 | ||
276 | /* If this is a pointer dereference of a non-SSA_NAME punt. | |
277 | ??? We could replace it with a pointer to anything. */ | |
278 | if (INDIRECT_REF_P (base) | |
279 | && TREE_CODE (TREE_OPERAND (base, 0)) != SSA_NAME) | |
280 | return false; | |
281 | ||
c9b2f286 RG |
282 | /* The tree oracle doesn't like to have these. */ |
283 | if (TREE_CODE (base) == FUNCTION_DECL | |
284 | || TREE_CODE (base) == LABEL_DECL) | |
285 | return false; | |
286 | ||
55b34b5f RG |
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) | |
297 | { | |
298 | ref->base_alias_set = get_alias_set (base); | |
299 | ref->base = build1 (INDIRECT_REF, TREE_TYPE (base), *(tree *)namep); | |
300 | } | |
301 | } | |
302 | ||
303 | ref->ref_alias_set = MEM_ALIAS_SET (mem); | |
304 | ||
305 | /* For NULL MEM_OFFSET the MEM_EXPR may have been stripped arbitrarily | |
306 | without recording offset or extent adjustments properly. */ | |
307 | if (MEM_OFFSET (mem) == NULL_RTX) | |
308 | { | |
309 | ref->offset = 0; | |
310 | ref->max_size = -1; | |
311 | } | |
312 | else | |
313 | { | |
314 | ref->offset += INTVAL (MEM_OFFSET (mem)) * BITS_PER_UNIT; | |
315 | } | |
316 | ||
317 | /* NULL MEM_SIZE should not really happen with a non-NULL MEM_EXPR, | |
318 | but just play safe here. The size may have been adjusted together | |
319 | with the offset, so we need to take it if it is set and not rely | |
320 | on MEM_EXPR here (which has the size determining parts potentially | |
321 | stripped anyway). We lose precision for max_size which is only | |
322 | available from the remaining MEM_EXPR. */ | |
323 | if (MEM_SIZE (mem) == NULL_RTX) | |
324 | { | |
325 | ref->size = -1; | |
326 | ref->max_size = -1; | |
327 | } | |
328 | else | |
329 | { | |
330 | ref->size = INTVAL (MEM_SIZE (mem)) * BITS_PER_UNIT; | |
331 | } | |
332 | ||
333 | return true; | |
334 | } | |
335 | ||
336 | /* Query the alias-oracle on whether the two memory rtx X and MEM may | |
337 | alias. If TBAA_P is set also apply TBAA. Returns true if the | |
338 | two rtxen may alias, false otherwise. */ | |
339 | ||
340 | static bool | |
341 | rtx_refs_may_alias_p (const_rtx x, const_rtx mem, bool tbaa_p) | |
342 | { | |
343 | ao_ref ref1, ref2; | |
344 | ||
345 | if (!ao_ref_from_mem (&ref1, x) | |
346 | || !ao_ref_from_mem (&ref2, mem)) | |
347 | return true; | |
348 | ||
349 | return refs_may_alias_p_1 (&ref1, &ref2, tbaa_p); | |
350 | } | |
351 | ||
3932261a MM |
352 | /* Returns a pointer to the alias set entry for ALIAS_SET, if there is |
353 | such an entry, or NULL otherwise. */ | |
354 | ||
9ddb66ca | 355 | static inline alias_set_entry |
4862826d | 356 | get_alias_set_entry (alias_set_type alias_set) |
3932261a | 357 | { |
1a5640b4 | 358 | return VEC_index (alias_set_entry, alias_sets, alias_set); |
3932261a MM |
359 | } |
360 | ||
ac3d9668 RK |
361 | /* Returns nonzero if the alias sets for MEM1 and MEM2 are such that |
362 | the two MEMs cannot alias each other. */ | |
3932261a | 363 | |
9ddb66ca | 364 | static inline int |
4f588890 | 365 | mems_in_disjoint_alias_sets_p (const_rtx mem1, const_rtx mem2) |
3932261a | 366 | { |
3932261a MM |
367 | /* Perform a basic sanity check. Namely, that there are no alias sets |
368 | if we're not using strict aliasing. This helps to catch bugs | |
369 | whereby someone uses PUT_CODE, but doesn't clear MEM_ALIAS_SET, or | |
370 | where a MEM is allocated in some way other than by the use of | |
371 | gen_rtx_MEM, and the MEM_ALIAS_SET is not cleared. If we begin to | |
372 | use alias sets to indicate that spilled registers cannot alias each | |
373 | other, we might need to remove this check. */ | |
298e6adc NS |
374 | gcc_assert (flag_strict_aliasing |
375 | || (!MEM_ALIAS_SET (mem1) && !MEM_ALIAS_SET (mem2))); | |
3932261a | 376 | |
1da68f56 RK |
377 | return ! alias_sets_conflict_p (MEM_ALIAS_SET (mem1), MEM_ALIAS_SET (mem2)); |
378 | } | |
3932261a | 379 | |
1da68f56 RK |
380 | /* Insert the NODE into the splay tree given by DATA. Used by |
381 | record_alias_subset via splay_tree_foreach. */ | |
382 | ||
383 | static int | |
4682ae04 | 384 | insert_subset_children (splay_tree_node node, void *data) |
1da68f56 RK |
385 | { |
386 | splay_tree_insert ((splay_tree) data, node->key, node->value); | |
387 | ||
388 | return 0; | |
389 | } | |
390 | ||
c58936b6 DB |
391 | /* Return true if the first alias set is a subset of the second. */ |
392 | ||
393 | bool | |
4862826d | 394 | alias_set_subset_of (alias_set_type set1, alias_set_type set2) |
c58936b6 DB |
395 | { |
396 | alias_set_entry ase; | |
397 | ||
398 | /* Everything is a subset of the "aliases everything" set. */ | |
399 | if (set2 == 0) | |
400 | return true; | |
401 | ||
402 | /* Otherwise, check if set1 is a subset of set2. */ | |
403 | ase = get_alias_set_entry (set2); | |
404 | if (ase != 0 | |
a7a512be RG |
405 | && ((ase->has_zero_child && set1 == 0) |
406 | || splay_tree_lookup (ase->children, | |
407 | (splay_tree_key) set1))) | |
c58936b6 DB |
408 | return true; |
409 | return false; | |
410 | } | |
411 | ||
1da68f56 RK |
412 | /* Return 1 if the two specified alias sets may conflict. */ |
413 | ||
414 | int | |
4862826d | 415 | alias_sets_conflict_p (alias_set_type set1, alias_set_type set2) |
1da68f56 RK |
416 | { |
417 | alias_set_entry ase; | |
418 | ||
836f7794 EB |
419 | /* The easy case. */ |
420 | if (alias_sets_must_conflict_p (set1, set2)) | |
1da68f56 | 421 | return 1; |
3932261a | 422 | |
3bdf5ad1 | 423 | /* See if the first alias set is a subset of the second. */ |
1da68f56 | 424 | ase = get_alias_set_entry (set1); |
2bf105ab RK |
425 | if (ase != 0 |
426 | && (ase->has_zero_child | |
427 | || splay_tree_lookup (ase->children, | |
1da68f56 RK |
428 | (splay_tree_key) set2))) |
429 | return 1; | |
3932261a MM |
430 | |
431 | /* Now do the same, but with the alias sets reversed. */ | |
1da68f56 | 432 | ase = get_alias_set_entry (set2); |
2bf105ab RK |
433 | if (ase != 0 |
434 | && (ase->has_zero_child | |
435 | || splay_tree_lookup (ase->children, | |
1da68f56 RK |
436 | (splay_tree_key) set1))) |
437 | return 1; | |
3932261a | 438 | |
1da68f56 | 439 | /* The two alias sets are distinct and neither one is the |
836f7794 | 440 | child of the other. Therefore, they cannot conflict. */ |
1da68f56 | 441 | return 0; |
3932261a | 442 | } |
5399d643 | 443 | |
71a6fe66 BM |
444 | static int |
445 | walk_mems_2 (rtx *x, rtx mem) | |
446 | { | |
447 | if (MEM_P (*x)) | |
448 | { | |
449 | if (alias_sets_conflict_p (MEM_ALIAS_SET(*x), MEM_ALIAS_SET(mem))) | |
450 | return 1; | |
451 | ||
452 | return -1; | |
453 | } | |
454 | return 0; | |
455 | } | |
456 | ||
457 | static int | |
458 | walk_mems_1 (rtx *x, rtx *pat) | |
459 | { | |
460 | if (MEM_P (*x)) | |
461 | { | |
462 | /* Visit all MEMs in *PAT and check indepedence. */ | |
463 | if (for_each_rtx (pat, (rtx_function) walk_mems_2, *x)) | |
464 | /* Indicate that dependence was determined and stop traversal. */ | |
465 | return 1; | |
466 | ||
467 | return -1; | |
468 | } | |
469 | return 0; | |
470 | } | |
471 | ||
472 | /* Return 1 if two specified instructions have mem expr with conflict alias sets*/ | |
473 | bool | |
474 | insn_alias_sets_conflict_p (rtx insn1, rtx insn2) | |
475 | { | |
476 | /* For each pair of MEMs in INSN1 and INSN2 check their independence. */ | |
477 | return for_each_rtx (&PATTERN (insn1), (rtx_function) walk_mems_1, | |
478 | &PATTERN (insn2)); | |
479 | } | |
480 | ||
836f7794 | 481 | /* Return 1 if the two specified alias sets will always conflict. */ |
5399d643 JW |
482 | |
483 | int | |
4862826d | 484 | alias_sets_must_conflict_p (alias_set_type set1, alias_set_type set2) |
5399d643 JW |
485 | { |
486 | if (set1 == 0 || set2 == 0 || set1 == set2) | |
487 | return 1; | |
488 | ||
489 | return 0; | |
490 | } | |
491 | ||
1da68f56 RK |
492 | /* Return 1 if any MEM object of type T1 will always conflict (using the |
493 | dependency routines in this file) with any MEM object of type T2. | |
494 | This is used when allocating temporary storage. If T1 and/or T2 are | |
495 | NULL_TREE, it means we know nothing about the storage. */ | |
496 | ||
497 | int | |
4682ae04 | 498 | objects_must_conflict_p (tree t1, tree t2) |
1da68f56 | 499 | { |
4862826d | 500 | alias_set_type set1, set2; |
82d610ec | 501 | |
e8ea2809 RK |
502 | /* If neither has a type specified, we don't know if they'll conflict |
503 | because we may be using them to store objects of various types, for | |
504 | example the argument and local variables areas of inlined functions. */ | |
981a4c34 | 505 | if (t1 == 0 && t2 == 0) |
e8ea2809 RK |
506 | return 0; |
507 | ||
1da68f56 RK |
508 | /* If they are the same type, they must conflict. */ |
509 | if (t1 == t2 | |
510 | /* Likewise if both are volatile. */ | |
511 | || (t1 != 0 && TYPE_VOLATILE (t1) && t2 != 0 && TYPE_VOLATILE (t2))) | |
512 | return 1; | |
513 | ||
82d610ec RK |
514 | set1 = t1 ? get_alias_set (t1) : 0; |
515 | set2 = t2 ? get_alias_set (t2) : 0; | |
1da68f56 | 516 | |
836f7794 EB |
517 | /* We can't use alias_sets_conflict_p because we must make sure |
518 | that every subtype of t1 will conflict with every subtype of | |
82d610ec RK |
519 | t2 for which a pair of subobjects of these respective subtypes |
520 | overlaps on the stack. */ | |
836f7794 | 521 | return alias_sets_must_conflict_p (set1, set2); |
1da68f56 RK |
522 | } |
523 | \f | |
2039d7aa RH |
524 | /* Return true if all nested component references handled by |
525 | get_inner_reference in T are such that we should use the alias set | |
526 | provided by the object at the heart of T. | |
527 | ||
528 | This is true for non-addressable components (which don't have their | |
529 | own alias set), as well as components of objects in alias set zero. | |
530 | This later point is a special case wherein we wish to override the | |
531 | alias set used by the component, but we don't have per-FIELD_DECL | |
532 | assignable alias sets. */ | |
533 | ||
534 | bool | |
22ea9ec0 | 535 | component_uses_parent_alias_set (const_tree t) |
6e24b709 | 536 | { |
afe84921 RH |
537 | while (1) |
538 | { | |
2039d7aa | 539 | /* If we're at the end, it vacuously uses its own alias set. */ |
afe84921 | 540 | if (!handled_component_p (t)) |
2039d7aa | 541 | return false; |
afe84921 RH |
542 | |
543 | switch (TREE_CODE (t)) | |
544 | { | |
545 | case COMPONENT_REF: | |
546 | if (DECL_NONADDRESSABLE_P (TREE_OPERAND (t, 1))) | |
2039d7aa | 547 | return true; |
afe84921 RH |
548 | break; |
549 | ||
550 | case ARRAY_REF: | |
551 | case ARRAY_RANGE_REF: | |
552 | if (TYPE_NONALIASED_COMPONENT (TREE_TYPE (TREE_OPERAND (t, 0)))) | |
2039d7aa | 553 | return true; |
afe84921 RH |
554 | break; |
555 | ||
556 | case REALPART_EXPR: | |
557 | case IMAGPART_EXPR: | |
558 | break; | |
559 | ||
560 | default: | |
561 | /* Bitfields and casts are never addressable. */ | |
2039d7aa | 562 | return true; |
afe84921 RH |
563 | } |
564 | ||
565 | t = TREE_OPERAND (t, 0); | |
2039d7aa RH |
566 | if (get_alias_set (TREE_TYPE (t)) == 0) |
567 | return true; | |
afe84921 | 568 | } |
6e24b709 RK |
569 | } |
570 | ||
5006671f RG |
571 | /* Return the alias set for the memory pointed to by T, which may be |
572 | either a type or an expression. Return -1 if there is nothing | |
573 | special about dereferencing T. */ | |
574 | ||
575 | static alias_set_type | |
576 | get_deref_alias_set_1 (tree t) | |
577 | { | |
578 | /* If we're not doing any alias analysis, just assume everything | |
579 | aliases everything else. */ | |
580 | if (!flag_strict_aliasing) | |
581 | return 0; | |
582 | ||
5b21f0f3 | 583 | /* All we care about is the type. */ |
5006671f | 584 | if (! TYPE_P (t)) |
5b21f0f3 | 585 | t = TREE_TYPE (t); |
5006671f RG |
586 | |
587 | /* If we have an INDIRECT_REF via a void pointer, we don't | |
588 | know anything about what that might alias. Likewise if the | |
589 | pointer is marked that way. */ | |
590 | if (TREE_CODE (TREE_TYPE (t)) == VOID_TYPE | |
591 | || TYPE_REF_CAN_ALIAS_ALL (t)) | |
592 | return 0; | |
593 | ||
594 | return -1; | |
595 | } | |
596 | ||
597 | /* Return the alias set for the memory pointed to by T, which may be | |
598 | either a type or an expression. */ | |
599 | ||
600 | alias_set_type | |
601 | get_deref_alias_set (tree t) | |
602 | { | |
603 | alias_set_type set = get_deref_alias_set_1 (t); | |
604 | ||
605 | /* Fall back to the alias-set of the pointed-to type. */ | |
606 | if (set == -1) | |
607 | { | |
608 | if (! TYPE_P (t)) | |
609 | t = TREE_TYPE (t); | |
610 | set = get_alias_set (TREE_TYPE (t)); | |
611 | } | |
612 | ||
613 | return set; | |
614 | } | |
615 | ||
3bdf5ad1 RK |
616 | /* Return the alias set for T, which may be either a type or an |
617 | expression. Call language-specific routine for help, if needed. */ | |
618 | ||
4862826d | 619 | alias_set_type |
4682ae04 | 620 | get_alias_set (tree t) |
3bdf5ad1 | 621 | { |
4862826d | 622 | alias_set_type set; |
3bdf5ad1 RK |
623 | |
624 | /* If we're not doing any alias analysis, just assume everything | |
625 | aliases everything else. Also return 0 if this or its type is | |
626 | an error. */ | |
627 | if (! flag_strict_aliasing || t == error_mark_node | |
628 | || (! TYPE_P (t) | |
629 | && (TREE_TYPE (t) == 0 || TREE_TYPE (t) == error_mark_node))) | |
630 | return 0; | |
631 | ||
632 | /* We can be passed either an expression or a type. This and the | |
f47e9b4e RK |
633 | language-specific routine may make mutually-recursive calls to each other |
634 | to figure out what to do. At each juncture, we see if this is a tree | |
635 | that the language may need to handle specially. First handle things that | |
738cc472 | 636 | aren't types. */ |
f824e5c3 | 637 | if (! TYPE_P (t)) |
3bdf5ad1 | 638 | { |
738cc472 | 639 | tree inner = t; |
738cc472 | 640 | |
8ac61af7 RK |
641 | /* Remove any nops, then give the language a chance to do |
642 | something with this tree before we look at it. */ | |
643 | STRIP_NOPS (t); | |
ae2bcd98 | 644 | set = lang_hooks.get_alias_set (t); |
8ac61af7 RK |
645 | if (set != -1) |
646 | return set; | |
647 | ||
738cc472 | 648 | /* First see if the actual object referenced is an INDIRECT_REF from a |
6fce44af RK |
649 | restrict-qualified pointer or a "void *". */ |
650 | while (handled_component_p (inner)) | |
738cc472 | 651 | { |
6fce44af | 652 | inner = TREE_OPERAND (inner, 0); |
8ac61af7 | 653 | STRIP_NOPS (inner); |
738cc472 RK |
654 | } |
655 | ||
1b096a0a | 656 | if (INDIRECT_REF_P (inner)) |
738cc472 | 657 | { |
5006671f RG |
658 | set = get_deref_alias_set_1 (TREE_OPERAND (inner, 0)); |
659 | if (set != -1) | |
660 | return set; | |
738cc472 RK |
661 | } |
662 | ||
663 | /* Otherwise, pick up the outermost object that we could have a pointer | |
6fce44af | 664 | to, processing conversions as above. */ |
2039d7aa | 665 | while (component_uses_parent_alias_set (t)) |
f47e9b4e | 666 | { |
6fce44af | 667 | t = TREE_OPERAND (t, 0); |
8ac61af7 RK |
668 | STRIP_NOPS (t); |
669 | } | |
f824e5c3 | 670 | |
738cc472 RK |
671 | /* If we've already determined the alias set for a decl, just return |
672 | it. This is necessary for C++ anonymous unions, whose component | |
673 | variables don't look like union members (boo!). */ | |
5755cd38 | 674 | if (TREE_CODE (t) == VAR_DECL |
3c0cb5de | 675 | && DECL_RTL_SET_P (t) && MEM_P (DECL_RTL (t))) |
5755cd38 JM |
676 | return MEM_ALIAS_SET (DECL_RTL (t)); |
677 | ||
f824e5c3 RK |
678 | /* Now all we care about is the type. */ |
679 | t = TREE_TYPE (t); | |
3bdf5ad1 RK |
680 | } |
681 | ||
3bdf5ad1 | 682 | /* Variant qualifiers don't affect the alias set, so get the main |
791f1714 RG |
683 | variant. Always use the canonical type as well. |
684 | If this is a type with a known alias set, return it. */ | |
3bdf5ad1 | 685 | t = TYPE_MAIN_VARIANT (t); |
791f1714 RG |
686 | if (TYPE_CANONICAL (t)) |
687 | t = TYPE_CANONICAL (t); | |
738cc472 | 688 | if (TYPE_ALIAS_SET_KNOWN_P (t)) |
3bdf5ad1 RK |
689 | return TYPE_ALIAS_SET (t); |
690 | ||
36784d0e RG |
691 | /* We don't want to set TYPE_ALIAS_SET for incomplete types. */ |
692 | if (!COMPLETE_TYPE_P (t)) | |
693 | { | |
694 | /* For arrays with unknown size the conservative answer is the | |
695 | alias set of the element type. */ | |
696 | if (TREE_CODE (t) == ARRAY_TYPE) | |
697 | return get_alias_set (TREE_TYPE (t)); | |
698 | ||
699 | /* But return zero as a conservative answer for incomplete types. */ | |
700 | return 0; | |
701 | } | |
702 | ||
3bdf5ad1 | 703 | /* See if the language has special handling for this type. */ |
ae2bcd98 | 704 | set = lang_hooks.get_alias_set (t); |
8ac61af7 | 705 | if (set != -1) |
738cc472 | 706 | return set; |
2bf105ab | 707 | |
3bdf5ad1 RK |
708 | /* There are no objects of FUNCTION_TYPE, so there's no point in |
709 | using up an alias set for them. (There are, of course, pointers | |
710 | and references to functions, but that's different.) */ | |
e11e491d RG |
711 | else if (TREE_CODE (t) == FUNCTION_TYPE |
712 | || TREE_CODE (t) == METHOD_TYPE) | |
3bdf5ad1 | 713 | set = 0; |
74d86f4f RH |
714 | |
715 | /* Unless the language specifies otherwise, let vector types alias | |
716 | their components. This avoids some nasty type punning issues in | |
717 | normal usage. And indeed lets vectors be treated more like an | |
718 | array slice. */ | |
719 | else if (TREE_CODE (t) == VECTOR_TYPE) | |
720 | set = get_alias_set (TREE_TYPE (t)); | |
721 | ||
4653cae5 RG |
722 | /* Unless the language specifies otherwise, treat array types the |
723 | same as their components. This avoids the asymmetry we get | |
724 | through recording the components. Consider accessing a | |
725 | character(kind=1) through a reference to a character(kind=1)[1:1]. | |
726 | Or consider if we want to assign integer(kind=4)[0:D.1387] and | |
727 | integer(kind=4)[4] the same alias set or not. | |
728 | Just be pragmatic here and make sure the array and its element | |
729 | type get the same alias set assigned. */ | |
730 | else if (TREE_CODE (t) == ARRAY_TYPE | |
731 | && !TYPE_NONALIASED_COMPONENT (t)) | |
732 | set = get_alias_set (TREE_TYPE (t)); | |
733 | ||
3bdf5ad1 RK |
734 | else |
735 | /* Otherwise make a new alias set for this type. */ | |
736 | set = new_alias_set (); | |
737 | ||
738 | TYPE_ALIAS_SET (t) = set; | |
2bf105ab RK |
739 | |
740 | /* If this is an aggregate type, we must record any component aliasing | |
741 | information. */ | |
1d79fd2c | 742 | if (AGGREGATE_TYPE_P (t) || TREE_CODE (t) == COMPLEX_TYPE) |
2bf105ab RK |
743 | record_component_aliases (t); |
744 | ||
3bdf5ad1 RK |
745 | return set; |
746 | } | |
747 | ||
748 | /* Return a brand-new alias set. */ | |
749 | ||
4862826d | 750 | alias_set_type |
4682ae04 | 751 | new_alias_set (void) |
3bdf5ad1 | 752 | { |
3bdf5ad1 | 753 | if (flag_strict_aliasing) |
9ddb66ca | 754 | { |
1a5640b4 KH |
755 | if (alias_sets == 0) |
756 | VEC_safe_push (alias_set_entry, gc, alias_sets, 0); | |
757 | VEC_safe_push (alias_set_entry, gc, alias_sets, 0); | |
758 | return VEC_length (alias_set_entry, alias_sets) - 1; | |
9ddb66ca | 759 | } |
3bdf5ad1 RK |
760 | else |
761 | return 0; | |
762 | } | |
3932261a | 763 | |
01d28c3f JM |
764 | /* Indicate that things in SUBSET can alias things in SUPERSET, but that |
765 | not everything that aliases SUPERSET also aliases SUBSET. For example, | |
766 | in C, a store to an `int' can alias a load of a structure containing an | |
767 | `int', and vice versa. But it can't alias a load of a 'double' member | |
768 | of the same structure. Here, the structure would be the SUPERSET and | |
769 | `int' the SUBSET. This relationship is also described in the comment at | |
770 | the beginning of this file. | |
771 | ||
772 | This function should be called only once per SUPERSET/SUBSET pair. | |
3932261a MM |
773 | |
774 | It is illegal for SUPERSET to be zero; everything is implicitly a | |
775 | subset of alias set zero. */ | |
776 | ||
794511d2 | 777 | void |
4862826d | 778 | record_alias_subset (alias_set_type superset, alias_set_type subset) |
3932261a MM |
779 | { |
780 | alias_set_entry superset_entry; | |
781 | alias_set_entry subset_entry; | |
782 | ||
f47e9b4e RK |
783 | /* It is possible in complex type situations for both sets to be the same, |
784 | in which case we can ignore this operation. */ | |
785 | if (superset == subset) | |
786 | return; | |
787 | ||
298e6adc | 788 | gcc_assert (superset); |
3932261a MM |
789 | |
790 | superset_entry = get_alias_set_entry (superset); | |
ca7fd9cd | 791 | if (superset_entry == 0) |
3932261a MM |
792 | { |
793 | /* Create an entry for the SUPERSET, so that we have a place to | |
794 | attach the SUBSET. */ | |
7e5487a2 | 795 | superset_entry = GGC_NEW (struct alias_set_entry_d); |
3932261a | 796 | superset_entry->alias_set = superset; |
ca7fd9cd | 797 | superset_entry->children |
b604074c | 798 | = splay_tree_new_ggc (splay_tree_compare_ints); |
570eb5c8 | 799 | superset_entry->has_zero_child = 0; |
1a5640b4 | 800 | VEC_replace (alias_set_entry, alias_sets, superset, superset_entry); |
3932261a MM |
801 | } |
802 | ||
2bf105ab RK |
803 | if (subset == 0) |
804 | superset_entry->has_zero_child = 1; | |
805 | else | |
806 | { | |
807 | subset_entry = get_alias_set_entry (subset); | |
808 | /* If there is an entry for the subset, enter all of its children | |
809 | (if they are not already present) as children of the SUPERSET. */ | |
ca7fd9cd | 810 | if (subset_entry) |
2bf105ab RK |
811 | { |
812 | if (subset_entry->has_zero_child) | |
813 | superset_entry->has_zero_child = 1; | |
d4b60170 | 814 | |
2bf105ab RK |
815 | splay_tree_foreach (subset_entry->children, insert_subset_children, |
816 | superset_entry->children); | |
817 | } | |
3932261a | 818 | |
2bf105ab | 819 | /* Enter the SUBSET itself as a child of the SUPERSET. */ |
ca7fd9cd | 820 | splay_tree_insert (superset_entry->children, |
2bf105ab RK |
821 | (splay_tree_key) subset, 0); |
822 | } | |
3932261a MM |
823 | } |
824 | ||
a0c33338 RK |
825 | /* Record that component types of TYPE, if any, are part of that type for |
826 | aliasing purposes. For record types, we only record component types | |
b5487346 EB |
827 | for fields that are not marked non-addressable. For array types, we |
828 | only record the component type if it is not marked non-aliased. */ | |
a0c33338 RK |
829 | |
830 | void | |
4682ae04 | 831 | record_component_aliases (tree type) |
a0c33338 | 832 | { |
4862826d | 833 | alias_set_type superset = get_alias_set (type); |
a0c33338 RK |
834 | tree field; |
835 | ||
836 | if (superset == 0) | |
837 | return; | |
838 | ||
839 | switch (TREE_CODE (type)) | |
840 | { | |
a0c33338 RK |
841 | case RECORD_TYPE: |
842 | case UNION_TYPE: | |
843 | case QUAL_UNION_TYPE: | |
6614fd40 | 844 | /* Recursively record aliases for the base classes, if there are any. */ |
fa743e8c | 845 | if (TYPE_BINFO (type)) |
ca7fd9cd KH |
846 | { |
847 | int i; | |
fa743e8c | 848 | tree binfo, base_binfo; |
c22cacf3 | 849 | |
fa743e8c NS |
850 | for (binfo = TYPE_BINFO (type), i = 0; |
851 | BINFO_BASE_ITERATE (binfo, i, base_binfo); i++) | |
852 | record_alias_subset (superset, | |
853 | get_alias_set (BINFO_TYPE (base_binfo))); | |
ca7fd9cd | 854 | } |
a0c33338 | 855 | for (field = TYPE_FIELDS (type); field != 0; field = TREE_CHAIN (field)) |
b5487346 | 856 | if (TREE_CODE (field) == FIELD_DECL && !DECL_NONADDRESSABLE_P (field)) |
2bf105ab | 857 | record_alias_subset (superset, get_alias_set (TREE_TYPE (field))); |
a0c33338 RK |
858 | break; |
859 | ||
1d79fd2c JW |
860 | case COMPLEX_TYPE: |
861 | record_alias_subset (superset, get_alias_set (TREE_TYPE (type))); | |
862 | break; | |
863 | ||
4653cae5 RG |
864 | /* VECTOR_TYPE and ARRAY_TYPE share the alias set with their |
865 | element type. */ | |
866 | ||
a0c33338 RK |
867 | default: |
868 | break; | |
869 | } | |
870 | } | |
871 | ||
3bdf5ad1 RK |
872 | /* Allocate an alias set for use in storing and reading from the varargs |
873 | spill area. */ | |
874 | ||
4862826d | 875 | static GTY(()) alias_set_type varargs_set = -1; |
f103e34d | 876 | |
4862826d | 877 | alias_set_type |
4682ae04 | 878 | get_varargs_alias_set (void) |
3bdf5ad1 | 879 | { |
cd3ce9b4 JM |
880 | #if 1 |
881 | /* We now lower VA_ARG_EXPR, and there's currently no way to attach the | |
882 | varargs alias set to an INDIRECT_REF (FIXME!), so we can't | |
883 | consistently use the varargs alias set for loads from the varargs | |
884 | area. So don't use it anywhere. */ | |
885 | return 0; | |
886 | #else | |
f103e34d GK |
887 | if (varargs_set == -1) |
888 | varargs_set = new_alias_set (); | |
3bdf5ad1 | 889 | |
f103e34d | 890 | return varargs_set; |
cd3ce9b4 | 891 | #endif |
3bdf5ad1 RK |
892 | } |
893 | ||
894 | /* Likewise, but used for the fixed portions of the frame, e.g., register | |
895 | save areas. */ | |
896 | ||
4862826d | 897 | static GTY(()) alias_set_type frame_set = -1; |
f103e34d | 898 | |
4862826d | 899 | alias_set_type |
4682ae04 | 900 | get_frame_alias_set (void) |
3bdf5ad1 | 901 | { |
f103e34d GK |
902 | if (frame_set == -1) |
903 | frame_set = new_alias_set (); | |
3bdf5ad1 | 904 | |
f103e34d | 905 | return frame_set; |
3bdf5ad1 RK |
906 | } |
907 | ||
2a2c8203 JC |
908 | /* Inside SRC, the source of a SET, find a base address. */ |
909 | ||
9ae8ffe7 | 910 | static rtx |
4682ae04 | 911 | find_base_value (rtx src) |
9ae8ffe7 | 912 | { |
713f41f9 | 913 | unsigned int regno; |
0aacc8ed | 914 | |
53451050 RS |
915 | #if defined (FIND_BASE_TERM) |
916 | /* Try machine-dependent ways to find the base term. */ | |
917 | src = FIND_BASE_TERM (src); | |
918 | #endif | |
919 | ||
9ae8ffe7 JL |
920 | switch (GET_CODE (src)) |
921 | { | |
922 | case SYMBOL_REF: | |
923 | case LABEL_REF: | |
924 | return src; | |
925 | ||
926 | case REG: | |
fb6754f0 | 927 | regno = REGNO (src); |
d4b60170 | 928 | /* At the start of a function, argument registers have known base |
2a2c8203 JC |
929 | values which may be lost later. Returning an ADDRESS |
930 | expression here allows optimization based on argument values | |
931 | even when the argument registers are used for other purposes. */ | |
713f41f9 BS |
932 | if (regno < FIRST_PSEUDO_REGISTER && copying_arguments) |
933 | return new_reg_base_value[regno]; | |
73774bc7 | 934 | |
eaf407a5 | 935 | /* If a pseudo has a known base value, return it. Do not do this |
9b462c42 RH |
936 | for non-fixed hard regs since it can result in a circular |
937 | dependency chain for registers which have values at function entry. | |
eaf407a5 JL |
938 | |
939 | The test above is not sufficient because the scheduler may move | |
940 | a copy out of an arg reg past the NOTE_INSN_FUNCTION_BEGIN. */ | |
9b462c42 | 941 | if ((regno >= FIRST_PSEUDO_REGISTER || fixed_regs[regno]) |
08c79682 | 942 | && regno < VEC_length (rtx, reg_base_value)) |
83bbd9b6 RH |
943 | { |
944 | /* If we're inside init_alias_analysis, use new_reg_base_value | |
945 | to reduce the number of relaxation iterations. */ | |
1afdf91c | 946 | if (new_reg_base_value && new_reg_base_value[regno] |
6fb5fa3c | 947 | && DF_REG_DEF_COUNT (regno) == 1) |
83bbd9b6 RH |
948 | return new_reg_base_value[regno]; |
949 | ||
08c79682 KH |
950 | if (VEC_index (rtx, reg_base_value, regno)) |
951 | return VEC_index (rtx, reg_base_value, regno); | |
83bbd9b6 | 952 | } |
73774bc7 | 953 | |
e3f049a8 | 954 | return 0; |
9ae8ffe7 JL |
955 | |
956 | case MEM: | |
957 | /* Check for an argument passed in memory. Only record in the | |
958 | copying-arguments block; it is too hard to track changes | |
959 | otherwise. */ | |
960 | if (copying_arguments | |
961 | && (XEXP (src, 0) == arg_pointer_rtx | |
962 | || (GET_CODE (XEXP (src, 0)) == PLUS | |
963 | && XEXP (XEXP (src, 0), 0) == arg_pointer_rtx))) | |
38a448ca | 964 | return gen_rtx_ADDRESS (VOIDmode, src); |
9ae8ffe7 JL |
965 | return 0; |
966 | ||
967 | case CONST: | |
968 | src = XEXP (src, 0); | |
969 | if (GET_CODE (src) != PLUS && GET_CODE (src) != MINUS) | |
970 | break; | |
d4b60170 | 971 | |
ec5c56db | 972 | /* ... fall through ... */ |
2a2c8203 | 973 | |
9ae8ffe7 JL |
974 | case PLUS: |
975 | case MINUS: | |
2a2c8203 | 976 | { |
ec907dd8 JL |
977 | rtx temp, src_0 = XEXP (src, 0), src_1 = XEXP (src, 1); |
978 | ||
0134bf2d DE |
979 | /* If either operand is a REG that is a known pointer, then it |
980 | is the base. */ | |
981 | if (REG_P (src_0) && REG_POINTER (src_0)) | |
982 | return find_base_value (src_0); | |
983 | if (REG_P (src_1) && REG_POINTER (src_1)) | |
984 | return find_base_value (src_1); | |
985 | ||
ec907dd8 JL |
986 | /* If either operand is a REG, then see if we already have |
987 | a known value for it. */ | |
0134bf2d | 988 | if (REG_P (src_0)) |
ec907dd8 JL |
989 | { |
990 | temp = find_base_value (src_0); | |
d4b60170 | 991 | if (temp != 0) |
ec907dd8 JL |
992 | src_0 = temp; |
993 | } | |
994 | ||
0134bf2d | 995 | if (REG_P (src_1)) |
ec907dd8 JL |
996 | { |
997 | temp = find_base_value (src_1); | |
d4b60170 | 998 | if (temp!= 0) |
ec907dd8 JL |
999 | src_1 = temp; |
1000 | } | |
2a2c8203 | 1001 | |
0134bf2d DE |
1002 | /* If either base is named object or a special address |
1003 | (like an argument or stack reference), then use it for the | |
1004 | base term. */ | |
1005 | if (src_0 != 0 | |
1006 | && (GET_CODE (src_0) == SYMBOL_REF | |
1007 | || GET_CODE (src_0) == LABEL_REF | |
1008 | || (GET_CODE (src_0) == ADDRESS | |
1009 | && GET_MODE (src_0) != VOIDmode))) | |
1010 | return src_0; | |
1011 | ||
1012 | if (src_1 != 0 | |
1013 | && (GET_CODE (src_1) == SYMBOL_REF | |
1014 | || GET_CODE (src_1) == LABEL_REF | |
1015 | || (GET_CODE (src_1) == ADDRESS | |
1016 | && GET_MODE (src_1) != VOIDmode))) | |
1017 | return src_1; | |
1018 | ||
d4b60170 | 1019 | /* Guess which operand is the base address: |
ec907dd8 JL |
1020 | If either operand is a symbol, then it is the base. If |
1021 | either operand is a CONST_INT, then the other is the base. */ | |
481683e1 | 1022 | if (CONST_INT_P (src_1) || CONSTANT_P (src_0)) |
2a2c8203 | 1023 | return find_base_value (src_0); |
481683e1 | 1024 | else if (CONST_INT_P (src_0) || CONSTANT_P (src_1)) |
ec907dd8 JL |
1025 | return find_base_value (src_1); |
1026 | ||
9ae8ffe7 | 1027 | return 0; |
2a2c8203 JC |
1028 | } |
1029 | ||
1030 | case LO_SUM: | |
1031 | /* The standard form is (lo_sum reg sym) so look only at the | |
1032 | second operand. */ | |
1033 | return find_base_value (XEXP (src, 1)); | |
9ae8ffe7 JL |
1034 | |
1035 | case AND: | |
1036 | /* If the second operand is constant set the base | |
ec5c56db | 1037 | address to the first operand. */ |
481683e1 | 1038 | if (CONST_INT_P (XEXP (src, 1)) && INTVAL (XEXP (src, 1)) != 0) |
2a2c8203 | 1039 | return find_base_value (XEXP (src, 0)); |
9ae8ffe7 JL |
1040 | return 0; |
1041 | ||
61f0131c R |
1042 | case TRUNCATE: |
1043 | if (GET_MODE_SIZE (GET_MODE (src)) < GET_MODE_SIZE (Pmode)) | |
1044 | break; | |
1045 | /* Fall through. */ | |
9ae8ffe7 | 1046 | case HIGH: |
d288e53d DE |
1047 | case PRE_INC: |
1048 | case PRE_DEC: | |
1049 | case POST_INC: | |
1050 | case POST_DEC: | |
1051 | case PRE_MODIFY: | |
1052 | case POST_MODIFY: | |
2a2c8203 | 1053 | return find_base_value (XEXP (src, 0)); |
1d300e19 | 1054 | |
0aacc8ed RK |
1055 | case ZERO_EXTEND: |
1056 | case SIGN_EXTEND: /* used for NT/Alpha pointers */ | |
1057 | { | |
1058 | rtx temp = find_base_value (XEXP (src, 0)); | |
1059 | ||
5ae6cd0d | 1060 | if (temp != 0 && CONSTANT_P (temp)) |
0aacc8ed | 1061 | temp = convert_memory_address (Pmode, temp); |
0aacc8ed RK |
1062 | |
1063 | return temp; | |
1064 | } | |
1065 | ||
1d300e19 KG |
1066 | default: |
1067 | break; | |
9ae8ffe7 JL |
1068 | } |
1069 | ||
1070 | return 0; | |
1071 | } | |
1072 | ||
1073 | /* Called from init_alias_analysis indirectly through note_stores. */ | |
1074 | ||
d4b60170 | 1075 | /* While scanning insns to find base values, reg_seen[N] is nonzero if |
9ae8ffe7 JL |
1076 | register N has been set in this function. */ |
1077 | static char *reg_seen; | |
1078 | ||
13309a5f JC |
1079 | /* Addresses which are known not to alias anything else are identified |
1080 | by a unique integer. */ | |
ec907dd8 JL |
1081 | static int unique_id; |
1082 | ||
2a2c8203 | 1083 | static void |
7bc980e1 | 1084 | record_set (rtx dest, const_rtx set, void *data ATTRIBUTE_UNUSED) |
9ae8ffe7 | 1085 | { |
b3694847 | 1086 | unsigned regno; |
9ae8ffe7 | 1087 | rtx src; |
c28b4e40 | 1088 | int n; |
9ae8ffe7 | 1089 | |
f8cfc6aa | 1090 | if (!REG_P (dest)) |
9ae8ffe7 JL |
1091 | return; |
1092 | ||
fb6754f0 | 1093 | regno = REGNO (dest); |
9ae8ffe7 | 1094 | |
08c79682 | 1095 | gcc_assert (regno < VEC_length (rtx, reg_base_value)); |
ac606739 | 1096 | |
c28b4e40 JW |
1097 | /* If this spans multiple hard registers, then we must indicate that every |
1098 | register has an unusable value. */ | |
1099 | if (regno < FIRST_PSEUDO_REGISTER) | |
66fd46b6 | 1100 | n = hard_regno_nregs[regno][GET_MODE (dest)]; |
c28b4e40 JW |
1101 | else |
1102 | n = 1; | |
1103 | if (n != 1) | |
1104 | { | |
1105 | while (--n >= 0) | |
1106 | { | |
1107 | reg_seen[regno + n] = 1; | |
1108 | new_reg_base_value[regno + n] = 0; | |
1109 | } | |
1110 | return; | |
1111 | } | |
1112 | ||
9ae8ffe7 JL |
1113 | if (set) |
1114 | { | |
1115 | /* A CLOBBER wipes out any old value but does not prevent a previously | |
1116 | unset register from acquiring a base address (i.e. reg_seen is not | |
1117 | set). */ | |
1118 | if (GET_CODE (set) == CLOBBER) | |
1119 | { | |
ec907dd8 | 1120 | new_reg_base_value[regno] = 0; |
9ae8ffe7 JL |
1121 | return; |
1122 | } | |
1123 | src = SET_SRC (set); | |
1124 | } | |
1125 | else | |
1126 | { | |
9ae8ffe7 JL |
1127 | if (reg_seen[regno]) |
1128 | { | |
ec907dd8 | 1129 | new_reg_base_value[regno] = 0; |
9ae8ffe7 JL |
1130 | return; |
1131 | } | |
1132 | reg_seen[regno] = 1; | |
38a448ca RH |
1133 | new_reg_base_value[regno] = gen_rtx_ADDRESS (Pmode, |
1134 | GEN_INT (unique_id++)); | |
9ae8ffe7 JL |
1135 | return; |
1136 | } | |
1137 | ||
5da6f168 RS |
1138 | /* If this is not the first set of REGNO, see whether the new value |
1139 | is related to the old one. There are two cases of interest: | |
1140 | ||
1141 | (1) The register might be assigned an entirely new value | |
1142 | that has the same base term as the original set. | |
1143 | ||
1144 | (2) The set might be a simple self-modification that | |
1145 | cannot change REGNO's base value. | |
1146 | ||
1147 | If neither case holds, reject the original base value as invalid. | |
1148 | Note that the following situation is not detected: | |
1149 | ||
c22cacf3 | 1150 | extern int x, y; int *p = &x; p += (&y-&x); |
5da6f168 | 1151 | |
9ae8ffe7 JL |
1152 | ANSI C does not allow computing the difference of addresses |
1153 | of distinct top level objects. */ | |
5da6f168 RS |
1154 | if (new_reg_base_value[regno] != 0 |
1155 | && find_base_value (src) != new_reg_base_value[regno]) | |
9ae8ffe7 JL |
1156 | switch (GET_CODE (src)) |
1157 | { | |
2a2c8203 | 1158 | case LO_SUM: |
9ae8ffe7 JL |
1159 | case MINUS: |
1160 | if (XEXP (src, 0) != dest && XEXP (src, 1) != dest) | |
ec907dd8 | 1161 | new_reg_base_value[regno] = 0; |
9ae8ffe7 | 1162 | break; |
61f0131c R |
1163 | case PLUS: |
1164 | /* If the value we add in the PLUS is also a valid base value, | |
1165 | this might be the actual base value, and the original value | |
1166 | an index. */ | |
1167 | { | |
1168 | rtx other = NULL_RTX; | |
1169 | ||
1170 | if (XEXP (src, 0) == dest) | |
1171 | other = XEXP (src, 1); | |
1172 | else if (XEXP (src, 1) == dest) | |
1173 | other = XEXP (src, 0); | |
1174 | ||
1175 | if (! other || find_base_value (other)) | |
1176 | new_reg_base_value[regno] = 0; | |
1177 | break; | |
1178 | } | |
9ae8ffe7 | 1179 | case AND: |
481683e1 | 1180 | if (XEXP (src, 0) != dest || !CONST_INT_P (XEXP (src, 1))) |
ec907dd8 | 1181 | new_reg_base_value[regno] = 0; |
9ae8ffe7 | 1182 | break; |
9ae8ffe7 | 1183 | default: |
ec907dd8 | 1184 | new_reg_base_value[regno] = 0; |
9ae8ffe7 JL |
1185 | break; |
1186 | } | |
1187 | /* If this is the first set of a register, record the value. */ | |
1188 | else if ((regno >= FIRST_PSEUDO_REGISTER || ! fixed_regs[regno]) | |
ec907dd8 JL |
1189 | && ! reg_seen[regno] && new_reg_base_value[regno] == 0) |
1190 | new_reg_base_value[regno] = find_base_value (src); | |
9ae8ffe7 JL |
1191 | |
1192 | reg_seen[regno] = 1; | |
1193 | } | |
1194 | ||
bb1acb3e RH |
1195 | /* If a value is known for REGNO, return it. */ |
1196 | ||
c22cacf3 | 1197 | rtx |
bb1acb3e RH |
1198 | get_reg_known_value (unsigned int regno) |
1199 | { | |
1200 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1201 | { | |
1202 | regno -= FIRST_PSEUDO_REGISTER; | |
1203 | if (regno < reg_known_value_size) | |
1204 | return reg_known_value[regno]; | |
1205 | } | |
1206 | return NULL; | |
43fe47ca JW |
1207 | } |
1208 | ||
bb1acb3e RH |
1209 | /* Set it. */ |
1210 | ||
1211 | static void | |
1212 | set_reg_known_value (unsigned int regno, rtx val) | |
1213 | { | |
1214 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1215 | { | |
1216 | regno -= FIRST_PSEUDO_REGISTER; | |
1217 | if (regno < reg_known_value_size) | |
1218 | reg_known_value[regno] = val; | |
1219 | } | |
1220 | } | |
1221 | ||
1222 | /* Similarly for reg_known_equiv_p. */ | |
1223 | ||
1224 | bool | |
1225 | get_reg_known_equiv_p (unsigned int regno) | |
1226 | { | |
1227 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1228 | { | |
1229 | regno -= FIRST_PSEUDO_REGISTER; | |
1230 | if (regno < reg_known_value_size) | |
1231 | return reg_known_equiv_p[regno]; | |
1232 | } | |
1233 | return false; | |
1234 | } | |
1235 | ||
1236 | static void | |
1237 | set_reg_known_equiv_p (unsigned int regno, bool val) | |
1238 | { | |
1239 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1240 | { | |
1241 | regno -= FIRST_PSEUDO_REGISTER; | |
1242 | if (regno < reg_known_value_size) | |
1243 | reg_known_equiv_p[regno] = val; | |
1244 | } | |
1245 | } | |
1246 | ||
1247 | ||
db048faf MM |
1248 | /* Returns a canonical version of X, from the point of view alias |
1249 | analysis. (For example, if X is a MEM whose address is a register, | |
1250 | and the register has a known value (say a SYMBOL_REF), then a MEM | |
1251 | whose address is the SYMBOL_REF is returned.) */ | |
1252 | ||
1253 | rtx | |
4682ae04 | 1254 | canon_rtx (rtx x) |
9ae8ffe7 JL |
1255 | { |
1256 | /* Recursively look for equivalences. */ | |
f8cfc6aa | 1257 | if (REG_P (x) && REGNO (x) >= FIRST_PSEUDO_REGISTER) |
bb1acb3e RH |
1258 | { |
1259 | rtx t = get_reg_known_value (REGNO (x)); | |
1260 | if (t == x) | |
1261 | return x; | |
1262 | if (t) | |
1263 | return canon_rtx (t); | |
1264 | } | |
1265 | ||
1266 | if (GET_CODE (x) == PLUS) | |
9ae8ffe7 JL |
1267 | { |
1268 | rtx x0 = canon_rtx (XEXP (x, 0)); | |
1269 | rtx x1 = canon_rtx (XEXP (x, 1)); | |
1270 | ||
1271 | if (x0 != XEXP (x, 0) || x1 != XEXP (x, 1)) | |
1272 | { | |
481683e1 | 1273 | if (CONST_INT_P (x0)) |
ed8908e7 | 1274 | return plus_constant (x1, INTVAL (x0)); |
481683e1 | 1275 | else if (CONST_INT_P (x1)) |
ed8908e7 | 1276 | return plus_constant (x0, INTVAL (x1)); |
38a448ca | 1277 | return gen_rtx_PLUS (GET_MODE (x), x0, x1); |
9ae8ffe7 JL |
1278 | } |
1279 | } | |
d4b60170 | 1280 | |
9ae8ffe7 JL |
1281 | /* This gives us much better alias analysis when called from |
1282 | the loop optimizer. Note we want to leave the original | |
1283 | MEM alone, but need to return the canonicalized MEM with | |
1284 | all the flags with their original values. */ | |
3c0cb5de | 1285 | else if (MEM_P (x)) |
f1ec5147 | 1286 | x = replace_equiv_address_nv (x, canon_rtx (XEXP (x, 0))); |
d4b60170 | 1287 | |
9ae8ffe7 JL |
1288 | return x; |
1289 | } | |
1290 | ||
1291 | /* Return 1 if X and Y are identical-looking rtx's. | |
45183e03 | 1292 | Expect that X and Y has been already canonicalized. |
9ae8ffe7 JL |
1293 | |
1294 | We use the data in reg_known_value above to see if two registers with | |
1295 | different numbers are, in fact, equivalent. */ | |
1296 | ||
1297 | static int | |
ed7a4b4b | 1298 | rtx_equal_for_memref_p (const_rtx x, const_rtx y) |
9ae8ffe7 | 1299 | { |
b3694847 SS |
1300 | int i; |
1301 | int j; | |
1302 | enum rtx_code code; | |
1303 | const char *fmt; | |
9ae8ffe7 JL |
1304 | |
1305 | if (x == 0 && y == 0) | |
1306 | return 1; | |
1307 | if (x == 0 || y == 0) | |
1308 | return 0; | |
d4b60170 | 1309 | |
9ae8ffe7 JL |
1310 | if (x == y) |
1311 | return 1; | |
1312 | ||
1313 | code = GET_CODE (x); | |
1314 | /* Rtx's of different codes cannot be equal. */ | |
1315 | if (code != GET_CODE (y)) | |
1316 | return 0; | |
1317 | ||
1318 | /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. | |
1319 | (REG:SI x) and (REG:HI x) are NOT equivalent. */ | |
1320 | ||
1321 | if (GET_MODE (x) != GET_MODE (y)) | |
1322 | return 0; | |
1323 | ||
db048faf MM |
1324 | /* Some RTL can be compared without a recursive examination. */ |
1325 | switch (code) | |
1326 | { | |
1327 | case REG: | |
1328 | return REGNO (x) == REGNO (y); | |
1329 | ||
1330 | case LABEL_REF: | |
1331 | return XEXP (x, 0) == XEXP (y, 0); | |
ca7fd9cd | 1332 | |
db048faf MM |
1333 | case SYMBOL_REF: |
1334 | return XSTR (x, 0) == XSTR (y, 0); | |
1335 | ||
40e02b4a | 1336 | case VALUE: |
db048faf MM |
1337 | case CONST_INT: |
1338 | case CONST_DOUBLE: | |
091a3ac7 | 1339 | case CONST_FIXED: |
db048faf MM |
1340 | /* There's no need to compare the contents of CONST_DOUBLEs or |
1341 | CONST_INTs because pointer equality is a good enough | |
1342 | comparison for these nodes. */ | |
1343 | return 0; | |
1344 | ||
db048faf MM |
1345 | default: |
1346 | break; | |
1347 | } | |
9ae8ffe7 | 1348 | |
45183e03 JH |
1349 | /* canon_rtx knows how to handle plus. No need to canonicalize. */ |
1350 | if (code == PLUS) | |
9ae8ffe7 JL |
1351 | return ((rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 0)) |
1352 | && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 1))) | |
1353 | || (rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 1)) | |
1354 | && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 0)))); | |
45183e03 JH |
1355 | /* For commutative operations, the RTX match if the operand match in any |
1356 | order. Also handle the simple binary and unary cases without a loop. */ | |
ec8e098d | 1357 | if (COMMUTATIVE_P (x)) |
45183e03 JH |
1358 | { |
1359 | rtx xop0 = canon_rtx (XEXP (x, 0)); | |
1360 | rtx yop0 = canon_rtx (XEXP (y, 0)); | |
1361 | rtx yop1 = canon_rtx (XEXP (y, 1)); | |
1362 | ||
1363 | return ((rtx_equal_for_memref_p (xop0, yop0) | |
1364 | && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), yop1)) | |
1365 | || (rtx_equal_for_memref_p (xop0, yop1) | |
1366 | && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), yop0))); | |
1367 | } | |
ec8e098d | 1368 | else if (NON_COMMUTATIVE_P (x)) |
45183e03 JH |
1369 | { |
1370 | return (rtx_equal_for_memref_p (canon_rtx (XEXP (x, 0)), | |
4682ae04 | 1371 | canon_rtx (XEXP (y, 0))) |
45183e03 JH |
1372 | && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), |
1373 | canon_rtx (XEXP (y, 1)))); | |
1374 | } | |
ec8e098d | 1375 | else if (UNARY_P (x)) |
45183e03 | 1376 | return rtx_equal_for_memref_p (canon_rtx (XEXP (x, 0)), |
4682ae04 | 1377 | canon_rtx (XEXP (y, 0))); |
9ae8ffe7 JL |
1378 | |
1379 | /* Compare the elements. If any pair of corresponding elements | |
de12be17 JC |
1380 | fail to match, return 0 for the whole things. |
1381 | ||
1382 | Limit cases to types which actually appear in addresses. */ | |
9ae8ffe7 JL |
1383 | |
1384 | fmt = GET_RTX_FORMAT (code); | |
1385 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
1386 | { | |
1387 | switch (fmt[i]) | |
1388 | { | |
9ae8ffe7 JL |
1389 | case 'i': |
1390 | if (XINT (x, i) != XINT (y, i)) | |
1391 | return 0; | |
1392 | break; | |
1393 | ||
9ae8ffe7 JL |
1394 | case 'E': |
1395 | /* Two vectors must have the same length. */ | |
1396 | if (XVECLEN (x, i) != XVECLEN (y, i)) | |
1397 | return 0; | |
1398 | ||
1399 | /* And the corresponding elements must match. */ | |
1400 | for (j = 0; j < XVECLEN (x, i); j++) | |
45183e03 JH |
1401 | if (rtx_equal_for_memref_p (canon_rtx (XVECEXP (x, i, j)), |
1402 | canon_rtx (XVECEXP (y, i, j))) == 0) | |
9ae8ffe7 JL |
1403 | return 0; |
1404 | break; | |
1405 | ||
1406 | case 'e': | |
45183e03 JH |
1407 | if (rtx_equal_for_memref_p (canon_rtx (XEXP (x, i)), |
1408 | canon_rtx (XEXP (y, i))) == 0) | |
9ae8ffe7 JL |
1409 | return 0; |
1410 | break; | |
1411 | ||
3237ac18 AH |
1412 | /* This can happen for asm operands. */ |
1413 | case 's': | |
1414 | if (strcmp (XSTR (x, i), XSTR (y, i))) | |
1415 | return 0; | |
1416 | break; | |
1417 | ||
aee21ba9 JL |
1418 | /* This can happen for an asm which clobbers memory. */ |
1419 | case '0': | |
1420 | break; | |
1421 | ||
9ae8ffe7 JL |
1422 | /* It is believed that rtx's at this level will never |
1423 | contain anything but integers and other rtx's, | |
1424 | except for within LABEL_REFs and SYMBOL_REFs. */ | |
1425 | default: | |
298e6adc | 1426 | gcc_unreachable (); |
9ae8ffe7 JL |
1427 | } |
1428 | } | |
1429 | return 1; | |
1430 | } | |
1431 | ||
94f24ddc | 1432 | rtx |
4682ae04 | 1433 | find_base_term (rtx x) |
9ae8ffe7 | 1434 | { |
eab5c70a BS |
1435 | cselib_val *val; |
1436 | struct elt_loc_list *l; | |
1437 | ||
b949ea8b JW |
1438 | #if defined (FIND_BASE_TERM) |
1439 | /* Try machine-dependent ways to find the base term. */ | |
1440 | x = FIND_BASE_TERM (x); | |
1441 | #endif | |
1442 | ||
9ae8ffe7 JL |
1443 | switch (GET_CODE (x)) |
1444 | { | |
1445 | case REG: | |
1446 | return REG_BASE_VALUE (x); | |
1447 | ||
d288e53d DE |
1448 | case TRUNCATE: |
1449 | if (GET_MODE_SIZE (GET_MODE (x)) < GET_MODE_SIZE (Pmode)) | |
ca7fd9cd | 1450 | return 0; |
d288e53d | 1451 | /* Fall through. */ |
9ae8ffe7 | 1452 | case HIGH: |
6d849a2a JL |
1453 | case PRE_INC: |
1454 | case PRE_DEC: | |
1455 | case POST_INC: | |
1456 | case POST_DEC: | |
d288e53d DE |
1457 | case PRE_MODIFY: |
1458 | case POST_MODIFY: | |
6d849a2a JL |
1459 | return find_base_term (XEXP (x, 0)); |
1460 | ||
1abade85 RK |
1461 | case ZERO_EXTEND: |
1462 | case SIGN_EXTEND: /* Used for Alpha/NT pointers */ | |
1463 | { | |
1464 | rtx temp = find_base_term (XEXP (x, 0)); | |
1465 | ||
5ae6cd0d | 1466 | if (temp != 0 && CONSTANT_P (temp)) |
1abade85 | 1467 | temp = convert_memory_address (Pmode, temp); |
1abade85 RK |
1468 | |
1469 | return temp; | |
1470 | } | |
1471 | ||
eab5c70a BS |
1472 | case VALUE: |
1473 | val = CSELIB_VAL_PTR (x); | |
40e02b4a JH |
1474 | if (!val) |
1475 | return 0; | |
eab5c70a BS |
1476 | for (l = val->locs; l; l = l->next) |
1477 | if ((x = find_base_term (l->loc)) != 0) | |
1478 | return x; | |
1479 | return 0; | |
1480 | ||
023f059b JJ |
1481 | case LO_SUM: |
1482 | /* The standard form is (lo_sum reg sym) so look only at the | |
1483 | second operand. */ | |
1484 | return find_base_term (XEXP (x, 1)); | |
1485 | ||
9ae8ffe7 JL |
1486 | case CONST: |
1487 | x = XEXP (x, 0); | |
1488 | if (GET_CODE (x) != PLUS && GET_CODE (x) != MINUS) | |
1489 | return 0; | |
938d968e | 1490 | /* Fall through. */ |
9ae8ffe7 JL |
1491 | case PLUS: |
1492 | case MINUS: | |
1493 | { | |
3c567fae JL |
1494 | rtx tmp1 = XEXP (x, 0); |
1495 | rtx tmp2 = XEXP (x, 1); | |
1496 | ||
f5143c46 | 1497 | /* This is a little bit tricky since we have to determine which of |
3c567fae JL |
1498 | the two operands represents the real base address. Otherwise this |
1499 | routine may return the index register instead of the base register. | |
1500 | ||
1501 | That may cause us to believe no aliasing was possible, when in | |
1502 | fact aliasing is possible. | |
1503 | ||
1504 | We use a few simple tests to guess the base register. Additional | |
1505 | tests can certainly be added. For example, if one of the operands | |
1506 | is a shift or multiply, then it must be the index register and the | |
1507 | other operand is the base register. */ | |
ca7fd9cd | 1508 | |
b949ea8b JW |
1509 | if (tmp1 == pic_offset_table_rtx && CONSTANT_P (tmp2)) |
1510 | return find_base_term (tmp2); | |
1511 | ||
3c567fae JL |
1512 | /* If either operand is known to be a pointer, then use it |
1513 | to determine the base term. */ | |
3502dc9c | 1514 | if (REG_P (tmp1) && REG_POINTER (tmp1)) |
7eba2d1f LM |
1515 | { |
1516 | rtx base = find_base_term (tmp1); | |
1517 | if (base) | |
1518 | return base; | |
1519 | } | |
3c567fae | 1520 | |
3502dc9c | 1521 | if (REG_P (tmp2) && REG_POINTER (tmp2)) |
7eba2d1f LM |
1522 | { |
1523 | rtx base = find_base_term (tmp2); | |
1524 | if (base) | |
1525 | return base; | |
1526 | } | |
3c567fae JL |
1527 | |
1528 | /* Neither operand was known to be a pointer. Go ahead and find the | |
1529 | base term for both operands. */ | |
1530 | tmp1 = find_base_term (tmp1); | |
1531 | tmp2 = find_base_term (tmp2); | |
1532 | ||
1533 | /* If either base term is named object or a special address | |
1534 | (like an argument or stack reference), then use it for the | |
1535 | base term. */ | |
d4b60170 | 1536 | if (tmp1 != 0 |
3c567fae JL |
1537 | && (GET_CODE (tmp1) == SYMBOL_REF |
1538 | || GET_CODE (tmp1) == LABEL_REF | |
1539 | || (GET_CODE (tmp1) == ADDRESS | |
1540 | && GET_MODE (tmp1) != VOIDmode))) | |
1541 | return tmp1; | |
1542 | ||
d4b60170 | 1543 | if (tmp2 != 0 |
3c567fae JL |
1544 | && (GET_CODE (tmp2) == SYMBOL_REF |
1545 | || GET_CODE (tmp2) == LABEL_REF | |
1546 | || (GET_CODE (tmp2) == ADDRESS | |
1547 | && GET_MODE (tmp2) != VOIDmode))) | |
1548 | return tmp2; | |
1549 | ||
1550 | /* We could not determine which of the two operands was the | |
1551 | base register and which was the index. So we can determine | |
1552 | nothing from the base alias check. */ | |
1553 | return 0; | |
9ae8ffe7 JL |
1554 | } |
1555 | ||
1556 | case AND: | |
481683e1 | 1557 | if (CONST_INT_P (XEXP (x, 1)) && INTVAL (XEXP (x, 1)) != 0) |
d288e53d | 1558 | return find_base_term (XEXP (x, 0)); |
9ae8ffe7 JL |
1559 | return 0; |
1560 | ||
1561 | case SYMBOL_REF: | |
1562 | case LABEL_REF: | |
1563 | return x; | |
1564 | ||
1565 | default: | |
1566 | return 0; | |
1567 | } | |
1568 | } | |
1569 | ||
1570 | /* Return 0 if the addresses X and Y are known to point to different | |
1571 | objects, 1 if they might be pointers to the same object. */ | |
1572 | ||
1573 | static int | |
4682ae04 AJ |
1574 | base_alias_check (rtx x, rtx y, enum machine_mode x_mode, |
1575 | enum machine_mode y_mode) | |
9ae8ffe7 JL |
1576 | { |
1577 | rtx x_base = find_base_term (x); | |
1578 | rtx y_base = find_base_term (y); | |
1579 | ||
1c72c7f6 JC |
1580 | /* If the address itself has no known base see if a known equivalent |
1581 | value has one. If either address still has no known base, nothing | |
1582 | is known about aliasing. */ | |
1583 | if (x_base == 0) | |
1584 | { | |
1585 | rtx x_c; | |
d4b60170 | 1586 | |
1c72c7f6 JC |
1587 | if (! flag_expensive_optimizations || (x_c = canon_rtx (x)) == x) |
1588 | return 1; | |
d4b60170 | 1589 | |
1c72c7f6 JC |
1590 | x_base = find_base_term (x_c); |
1591 | if (x_base == 0) | |
1592 | return 1; | |
1593 | } | |
9ae8ffe7 | 1594 | |
1c72c7f6 JC |
1595 | if (y_base == 0) |
1596 | { | |
1597 | rtx y_c; | |
1598 | if (! flag_expensive_optimizations || (y_c = canon_rtx (y)) == y) | |
1599 | return 1; | |
d4b60170 | 1600 | |
1c72c7f6 JC |
1601 | y_base = find_base_term (y_c); |
1602 | if (y_base == 0) | |
1603 | return 1; | |
1604 | } | |
1605 | ||
1606 | /* If the base addresses are equal nothing is known about aliasing. */ | |
1607 | if (rtx_equal_p (x_base, y_base)) | |
9ae8ffe7 JL |
1608 | return 1; |
1609 | ||
435da628 UB |
1610 | /* The base addresses are different expressions. If they are not accessed |
1611 | via AND, there is no conflict. We can bring knowledge of object | |
1612 | alignment into play here. For example, on alpha, "char a, b;" can | |
1613 | alias one another, though "char a; long b;" cannot. AND addesses may | |
1614 | implicitly alias surrounding objects; i.e. unaligned access in DImode | |
1615 | via AND address can alias all surrounding object types except those | |
1616 | with aligment 8 or higher. */ | |
1617 | if (GET_CODE (x) == AND && GET_CODE (y) == AND) | |
1618 | return 1; | |
1619 | if (GET_CODE (x) == AND | |
481683e1 | 1620 | && (!CONST_INT_P (XEXP (x, 1)) |
435da628 UB |
1621 | || (int) GET_MODE_UNIT_SIZE (y_mode) < -INTVAL (XEXP (x, 1)))) |
1622 | return 1; | |
1623 | if (GET_CODE (y) == AND | |
481683e1 | 1624 | && (!CONST_INT_P (XEXP (y, 1)) |
435da628 UB |
1625 | || (int) GET_MODE_UNIT_SIZE (x_mode) < -INTVAL (XEXP (y, 1)))) |
1626 | return 1; | |
1627 | ||
1628 | /* Differing symbols not accessed via AND never alias. */ | |
9ae8ffe7 | 1629 | if (GET_CODE (x_base) != ADDRESS && GET_CODE (y_base) != ADDRESS) |
435da628 | 1630 | return 0; |
9ae8ffe7 JL |
1631 | |
1632 | /* If one address is a stack reference there can be no alias: | |
1633 | stack references using different base registers do not alias, | |
1634 | a stack reference can not alias a parameter, and a stack reference | |
1635 | can not alias a global. */ | |
1636 | if ((GET_CODE (x_base) == ADDRESS && GET_MODE (x_base) == Pmode) | |
1637 | || (GET_CODE (y_base) == ADDRESS && GET_MODE (y_base) == Pmode)) | |
1638 | return 0; | |
1639 | ||
1640 | if (! flag_argument_noalias) | |
1641 | return 1; | |
1642 | ||
1643 | if (flag_argument_noalias > 1) | |
1644 | return 0; | |
1645 | ||
ec5c56db | 1646 | /* Weak noalias assertion (arguments are distinct, but may match globals). */ |
9ae8ffe7 JL |
1647 | return ! (GET_MODE (x_base) == VOIDmode && GET_MODE (y_base) == VOIDmode); |
1648 | } | |
1649 | ||
eab5c70a BS |
1650 | /* Convert the address X into something we can use. This is done by returning |
1651 | it unchanged unless it is a value; in the latter case we call cselib to get | |
1652 | a more useful rtx. */ | |
3bdf5ad1 | 1653 | |
a13d4ebf | 1654 | rtx |
4682ae04 | 1655 | get_addr (rtx x) |
eab5c70a BS |
1656 | { |
1657 | cselib_val *v; | |
1658 | struct elt_loc_list *l; | |
1659 | ||
1660 | if (GET_CODE (x) != VALUE) | |
1661 | return x; | |
1662 | v = CSELIB_VAL_PTR (x); | |
40e02b4a JH |
1663 | if (v) |
1664 | { | |
1665 | for (l = v->locs; l; l = l->next) | |
1666 | if (CONSTANT_P (l->loc)) | |
1667 | return l->loc; | |
1668 | for (l = v->locs; l; l = l->next) | |
3c0cb5de | 1669 | if (!REG_P (l->loc) && !MEM_P (l->loc)) |
40e02b4a JH |
1670 | return l->loc; |
1671 | if (v->locs) | |
1672 | return v->locs->loc; | |
1673 | } | |
eab5c70a BS |
1674 | return x; |
1675 | } | |
1676 | ||
39cec1ac MH |
1677 | /* Return the address of the (N_REFS + 1)th memory reference to ADDR |
1678 | where SIZE is the size in bytes of the memory reference. If ADDR | |
1679 | is not modified by the memory reference then ADDR is returned. */ | |
1680 | ||
04e2b4d3 | 1681 | static rtx |
4682ae04 | 1682 | addr_side_effect_eval (rtx addr, int size, int n_refs) |
39cec1ac MH |
1683 | { |
1684 | int offset = 0; | |
ca7fd9cd | 1685 | |
39cec1ac MH |
1686 | switch (GET_CODE (addr)) |
1687 | { | |
1688 | case PRE_INC: | |
1689 | offset = (n_refs + 1) * size; | |
1690 | break; | |
1691 | case PRE_DEC: | |
1692 | offset = -(n_refs + 1) * size; | |
1693 | break; | |
1694 | case POST_INC: | |
1695 | offset = n_refs * size; | |
1696 | break; | |
1697 | case POST_DEC: | |
1698 | offset = -n_refs * size; | |
1699 | break; | |
1700 | ||
1701 | default: | |
1702 | return addr; | |
1703 | } | |
ca7fd9cd | 1704 | |
39cec1ac | 1705 | if (offset) |
45183e03 | 1706 | addr = gen_rtx_PLUS (GET_MODE (addr), XEXP (addr, 0), |
c22cacf3 | 1707 | GEN_INT (offset)); |
39cec1ac MH |
1708 | else |
1709 | addr = XEXP (addr, 0); | |
45183e03 | 1710 | addr = canon_rtx (addr); |
39cec1ac MH |
1711 | |
1712 | return addr; | |
1713 | } | |
1714 | ||
9ae8ffe7 JL |
1715 | /* Return nonzero if X and Y (memory addresses) could reference the |
1716 | same location in memory. C is an offset accumulator. When | |
1717 | C is nonzero, we are testing aliases between X and Y + C. | |
1718 | XSIZE is the size in bytes of the X reference, | |
1719 | similarly YSIZE is the size in bytes for Y. | |
45183e03 | 1720 | Expect that canon_rtx has been already called for X and Y. |
9ae8ffe7 JL |
1721 | |
1722 | If XSIZE or YSIZE is zero, we do not know the amount of memory being | |
1723 | referenced (the reference was BLKmode), so make the most pessimistic | |
1724 | assumptions. | |
1725 | ||
c02f035f RH |
1726 | If XSIZE or YSIZE is negative, we may access memory outside the object |
1727 | being referenced as a side effect. This can happen when using AND to | |
1728 | align memory references, as is done on the Alpha. | |
1729 | ||
9ae8ffe7 | 1730 | Nice to notice that varying addresses cannot conflict with fp if no |
0211b6ab | 1731 | local variables had their addresses taken, but that's too hard now. */ |
9ae8ffe7 | 1732 | |
9ae8ffe7 | 1733 | static int |
4682ae04 | 1734 | memrefs_conflict_p (int xsize, rtx x, int ysize, rtx y, HOST_WIDE_INT c) |
9ae8ffe7 | 1735 | { |
eab5c70a BS |
1736 | if (GET_CODE (x) == VALUE) |
1737 | x = get_addr (x); | |
1738 | if (GET_CODE (y) == VALUE) | |
1739 | y = get_addr (y); | |
9ae8ffe7 JL |
1740 | if (GET_CODE (x) == HIGH) |
1741 | x = XEXP (x, 0); | |
1742 | else if (GET_CODE (x) == LO_SUM) | |
1743 | x = XEXP (x, 1); | |
1744 | else | |
45183e03 | 1745 | x = addr_side_effect_eval (x, xsize, 0); |
9ae8ffe7 JL |
1746 | if (GET_CODE (y) == HIGH) |
1747 | y = XEXP (y, 0); | |
1748 | else if (GET_CODE (y) == LO_SUM) | |
1749 | y = XEXP (y, 1); | |
1750 | else | |
45183e03 | 1751 | y = addr_side_effect_eval (y, ysize, 0); |
9ae8ffe7 JL |
1752 | |
1753 | if (rtx_equal_for_memref_p (x, y)) | |
1754 | { | |
c02f035f | 1755 | if (xsize <= 0 || ysize <= 0) |
9ae8ffe7 JL |
1756 | return 1; |
1757 | if (c >= 0 && xsize > c) | |
1758 | return 1; | |
1759 | if (c < 0 && ysize+c > 0) | |
1760 | return 1; | |
1761 | return 0; | |
1762 | } | |
1763 | ||
6e73e666 JC |
1764 | /* This code used to check for conflicts involving stack references and |
1765 | globals but the base address alias code now handles these cases. */ | |
9ae8ffe7 JL |
1766 | |
1767 | if (GET_CODE (x) == PLUS) | |
1768 | { | |
1769 | /* The fact that X is canonicalized means that this | |
1770 | PLUS rtx is canonicalized. */ | |
1771 | rtx x0 = XEXP (x, 0); | |
1772 | rtx x1 = XEXP (x, 1); | |
1773 | ||
1774 | if (GET_CODE (y) == PLUS) | |
1775 | { | |
1776 | /* The fact that Y is canonicalized means that this | |
1777 | PLUS rtx is canonicalized. */ | |
1778 | rtx y0 = XEXP (y, 0); | |
1779 | rtx y1 = XEXP (y, 1); | |
1780 | ||
1781 | if (rtx_equal_for_memref_p (x1, y1)) | |
1782 | return memrefs_conflict_p (xsize, x0, ysize, y0, c); | |
1783 | if (rtx_equal_for_memref_p (x0, y0)) | |
1784 | return memrefs_conflict_p (xsize, x1, ysize, y1, c); | |
481683e1 | 1785 | if (CONST_INT_P (x1)) |
63be02db | 1786 | { |
481683e1 | 1787 | if (CONST_INT_P (y1)) |
63be02db JM |
1788 | return memrefs_conflict_p (xsize, x0, ysize, y0, |
1789 | c - INTVAL (x1) + INTVAL (y1)); | |
1790 | else | |
1791 | return memrefs_conflict_p (xsize, x0, ysize, y, | |
1792 | c - INTVAL (x1)); | |
1793 | } | |
481683e1 | 1794 | else if (CONST_INT_P (y1)) |
9ae8ffe7 JL |
1795 | return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1)); |
1796 | ||
6e73e666 | 1797 | return 1; |
9ae8ffe7 | 1798 | } |
481683e1 | 1799 | else if (CONST_INT_P (x1)) |
9ae8ffe7 JL |
1800 | return memrefs_conflict_p (xsize, x0, ysize, y, c - INTVAL (x1)); |
1801 | } | |
1802 | else if (GET_CODE (y) == PLUS) | |
1803 | { | |
1804 | /* The fact that Y is canonicalized means that this | |
1805 | PLUS rtx is canonicalized. */ | |
1806 | rtx y0 = XEXP (y, 0); | |
1807 | rtx y1 = XEXP (y, 1); | |
1808 | ||
481683e1 | 1809 | if (CONST_INT_P (y1)) |
9ae8ffe7 JL |
1810 | return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1)); |
1811 | else | |
1812 | return 1; | |
1813 | } | |
1814 | ||
1815 | if (GET_CODE (x) == GET_CODE (y)) | |
1816 | switch (GET_CODE (x)) | |
1817 | { | |
1818 | case MULT: | |
1819 | { | |
1820 | /* Handle cases where we expect the second operands to be the | |
1821 | same, and check only whether the first operand would conflict | |
1822 | or not. */ | |
1823 | rtx x0, y0; | |
1824 | rtx x1 = canon_rtx (XEXP (x, 1)); | |
1825 | rtx y1 = canon_rtx (XEXP (y, 1)); | |
1826 | if (! rtx_equal_for_memref_p (x1, y1)) | |
1827 | return 1; | |
1828 | x0 = canon_rtx (XEXP (x, 0)); | |
1829 | y0 = canon_rtx (XEXP (y, 0)); | |
1830 | if (rtx_equal_for_memref_p (x0, y0)) | |
1831 | return (xsize == 0 || ysize == 0 | |
1832 | || (c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)); | |
1833 | ||
1834 | /* Can't properly adjust our sizes. */ | |
481683e1 | 1835 | if (!CONST_INT_P (x1)) |
9ae8ffe7 JL |
1836 | return 1; |
1837 | xsize /= INTVAL (x1); | |
1838 | ysize /= INTVAL (x1); | |
1839 | c /= INTVAL (x1); | |
1840 | return memrefs_conflict_p (xsize, x0, ysize, y0, c); | |
1841 | } | |
1d300e19 KG |
1842 | |
1843 | default: | |
1844 | break; | |
9ae8ffe7 JL |
1845 | } |
1846 | ||
1847 | /* Treat an access through an AND (e.g. a subword access on an Alpha) | |
ca7fd9cd | 1848 | as an access with indeterminate size. Assume that references |
56ee9281 RH |
1849 | besides AND are aligned, so if the size of the other reference is |
1850 | at least as large as the alignment, assume no other overlap. */ | |
481683e1 | 1851 | if (GET_CODE (x) == AND && CONST_INT_P (XEXP (x, 1))) |
56ee9281 | 1852 | { |
02e3377d | 1853 | if (GET_CODE (y) == AND || ysize < -INTVAL (XEXP (x, 1))) |
56ee9281 | 1854 | xsize = -1; |
45183e03 | 1855 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), ysize, y, c); |
56ee9281 | 1856 | } |
481683e1 | 1857 | if (GET_CODE (y) == AND && CONST_INT_P (XEXP (y, 1))) |
c02f035f | 1858 | { |
56ee9281 | 1859 | /* ??? If we are indexing far enough into the array/structure, we |
ca7fd9cd | 1860 | may yet be able to determine that we can not overlap. But we |
c02f035f | 1861 | also need to that we are far enough from the end not to overlap |
56ee9281 | 1862 | a following reference, so we do nothing with that for now. */ |
02e3377d | 1863 | if (GET_CODE (x) == AND || xsize < -INTVAL (XEXP (y, 1))) |
56ee9281 | 1864 | ysize = -1; |
45183e03 | 1865 | return memrefs_conflict_p (xsize, x, ysize, canon_rtx (XEXP (y, 0)), c); |
c02f035f | 1866 | } |
9ae8ffe7 JL |
1867 | |
1868 | if (CONSTANT_P (x)) | |
1869 | { | |
481683e1 | 1870 | if (CONST_INT_P (x) && CONST_INT_P (y)) |
9ae8ffe7 JL |
1871 | { |
1872 | c += (INTVAL (y) - INTVAL (x)); | |
c02f035f | 1873 | return (xsize <= 0 || ysize <= 0 |
9ae8ffe7 JL |
1874 | || (c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)); |
1875 | } | |
1876 | ||
1877 | if (GET_CODE (x) == CONST) | |
1878 | { | |
1879 | if (GET_CODE (y) == CONST) | |
1880 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), | |
1881 | ysize, canon_rtx (XEXP (y, 0)), c); | |
1882 | else | |
1883 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), | |
1884 | ysize, y, c); | |
1885 | } | |
1886 | if (GET_CODE (y) == CONST) | |
1887 | return memrefs_conflict_p (xsize, x, ysize, | |
1888 | canon_rtx (XEXP (y, 0)), c); | |
1889 | ||
1890 | if (CONSTANT_P (y)) | |
b949ea8b | 1891 | return (xsize <= 0 || ysize <= 0 |
c02f035f | 1892 | || (rtx_equal_for_memref_p (x, y) |
b949ea8b | 1893 | && ((c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)))); |
9ae8ffe7 JL |
1894 | |
1895 | return 1; | |
1896 | } | |
1897 | return 1; | |
1898 | } | |
1899 | ||
1900 | /* Functions to compute memory dependencies. | |
1901 | ||
1902 | Since we process the insns in execution order, we can build tables | |
1903 | to keep track of what registers are fixed (and not aliased), what registers | |
1904 | are varying in known ways, and what registers are varying in unknown | |
1905 | ways. | |
1906 | ||
1907 | If both memory references are volatile, then there must always be a | |
1908 | dependence between the two references, since their order can not be | |
1909 | changed. A volatile and non-volatile reference can be interchanged | |
ca7fd9cd | 1910 | though. |
9ae8ffe7 | 1911 | |
dc1618bc RK |
1912 | A MEM_IN_STRUCT reference at a non-AND varying address can never |
1913 | conflict with a non-MEM_IN_STRUCT reference at a fixed address. We | |
1914 | also must allow AND addresses, because they may generate accesses | |
1915 | outside the object being referenced. This is used to generate | |
1916 | aligned addresses from unaligned addresses, for instance, the alpha | |
1917 | storeqi_unaligned pattern. */ | |
9ae8ffe7 JL |
1918 | |
1919 | /* Read dependence: X is read after read in MEM takes place. There can | |
1920 | only be a dependence here if both reads are volatile. */ | |
1921 | ||
1922 | int | |
4f588890 | 1923 | read_dependence (const_rtx mem, const_rtx x) |
9ae8ffe7 JL |
1924 | { |
1925 | return MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem); | |
1926 | } | |
1927 | ||
c6df88cb MM |
1928 | /* Returns MEM1 if and only if MEM1 is a scalar at a fixed address and |
1929 | MEM2 is a reference to a structure at a varying address, or returns | |
1930 | MEM2 if vice versa. Otherwise, returns NULL_RTX. If a non-NULL | |
1931 | value is returned MEM1 and MEM2 can never alias. VARIES_P is used | |
1932 | to decide whether or not an address may vary; it should return | |
eab5c70a BS |
1933 | nonzero whenever variation is possible. |
1934 | MEM1_ADDR and MEM2_ADDR are the addresses of MEM1 and MEM2. */ | |
ca7fd9cd | 1935 | |
4f588890 KG |
1936 | static const_rtx |
1937 | fixed_scalar_and_varying_struct_p (const_rtx mem1, const_rtx mem2, rtx mem1_addr, | |
4682ae04 | 1938 | rtx mem2_addr, |
4f588890 | 1939 | bool (*varies_p) (const_rtx, bool)) |
ca7fd9cd | 1940 | { |
3e0abe15 GK |
1941 | if (! flag_strict_aliasing) |
1942 | return NULL_RTX; | |
1943 | ||
afa8f0fb AP |
1944 | if (MEM_ALIAS_SET (mem2) |
1945 | && MEM_SCALAR_P (mem1) && MEM_IN_STRUCT_P (mem2) | |
e38fe8e0 | 1946 | && !varies_p (mem1_addr, 1) && varies_p (mem2_addr, 1)) |
c6df88cb MM |
1947 | /* MEM1 is a scalar at a fixed address; MEM2 is a struct at a |
1948 | varying address. */ | |
1949 | return mem1; | |
1950 | ||
afa8f0fb AP |
1951 | if (MEM_ALIAS_SET (mem1) |
1952 | && MEM_IN_STRUCT_P (mem1) && MEM_SCALAR_P (mem2) | |
e38fe8e0 | 1953 | && varies_p (mem1_addr, 1) && !varies_p (mem2_addr, 1)) |
c6df88cb MM |
1954 | /* MEM2 is a scalar at a fixed address; MEM1 is a struct at a |
1955 | varying address. */ | |
1956 | return mem2; | |
1957 | ||
1958 | return NULL_RTX; | |
1959 | } | |
1960 | ||
1961 | /* Returns nonzero if something about the mode or address format MEM1 | |
1962 | indicates that it might well alias *anything*. */ | |
1963 | ||
2c72b78f | 1964 | static int |
4f588890 | 1965 | aliases_everything_p (const_rtx mem) |
c6df88cb | 1966 | { |
c6df88cb | 1967 | if (GET_CODE (XEXP (mem, 0)) == AND) |
35fd3193 | 1968 | /* If the address is an AND, it's very hard to know at what it is |
c6df88cb MM |
1969 | actually pointing. */ |
1970 | return 1; | |
ca7fd9cd | 1971 | |
c6df88cb MM |
1972 | return 0; |
1973 | } | |
1974 | ||
998d7deb RH |
1975 | /* Return true if we can determine that the fields referenced cannot |
1976 | overlap for any pair of objects. */ | |
1977 | ||
1978 | static bool | |
4f588890 | 1979 | nonoverlapping_component_refs_p (const_tree x, const_tree y) |
998d7deb | 1980 | { |
4f588890 | 1981 | const_tree fieldx, fieldy, typex, typey, orig_y; |
998d7deb RH |
1982 | |
1983 | do | |
1984 | { | |
1985 | /* The comparison has to be done at a common type, since we don't | |
d6a7951f | 1986 | know how the inheritance hierarchy works. */ |
998d7deb RH |
1987 | orig_y = y; |
1988 | do | |
1989 | { | |
1990 | fieldx = TREE_OPERAND (x, 1); | |
c05a0766 | 1991 | typex = TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (fieldx)); |
998d7deb RH |
1992 | |
1993 | y = orig_y; | |
1994 | do | |
1995 | { | |
1996 | fieldy = TREE_OPERAND (y, 1); | |
c05a0766 | 1997 | typey = TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (fieldy)); |
998d7deb RH |
1998 | |
1999 | if (typex == typey) | |
2000 | goto found; | |
2001 | ||
2002 | y = TREE_OPERAND (y, 0); | |
2003 | } | |
2004 | while (y && TREE_CODE (y) == COMPONENT_REF); | |
2005 | ||
2006 | x = TREE_OPERAND (x, 0); | |
2007 | } | |
2008 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
998d7deb | 2009 | /* Never found a common type. */ |
c05a0766 | 2010 | return false; |
998d7deb RH |
2011 | |
2012 | found: | |
2013 | /* If we're left with accessing different fields of a structure, | |
2014 | then no overlap. */ | |
2015 | if (TREE_CODE (typex) == RECORD_TYPE | |
2016 | && fieldx != fieldy) | |
2017 | return true; | |
2018 | ||
2019 | /* The comparison on the current field failed. If we're accessing | |
2020 | a very nested structure, look at the next outer level. */ | |
2021 | x = TREE_OPERAND (x, 0); | |
2022 | y = TREE_OPERAND (y, 0); | |
2023 | } | |
2024 | while (x && y | |
2025 | && TREE_CODE (x) == COMPONENT_REF | |
2026 | && TREE_CODE (y) == COMPONENT_REF); | |
ca7fd9cd | 2027 | |
998d7deb RH |
2028 | return false; |
2029 | } | |
2030 | ||
2031 | /* Look at the bottom of the COMPONENT_REF list for a DECL, and return it. */ | |
2032 | ||
2033 | static tree | |
4682ae04 | 2034 | decl_for_component_ref (tree x) |
998d7deb RH |
2035 | { |
2036 | do | |
2037 | { | |
2038 | x = TREE_OPERAND (x, 0); | |
2039 | } | |
2040 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
2041 | ||
2042 | return x && DECL_P (x) ? x : NULL_TREE; | |
2043 | } | |
2044 | ||
2045 | /* Walk up the COMPONENT_REF list and adjust OFFSET to compensate for the | |
2046 | offset of the field reference. */ | |
2047 | ||
2048 | static rtx | |
4682ae04 | 2049 | adjust_offset_for_component_ref (tree x, rtx offset) |
998d7deb RH |
2050 | { |
2051 | HOST_WIDE_INT ioffset; | |
2052 | ||
2053 | if (! offset) | |
2054 | return NULL_RTX; | |
2055 | ||
2056 | ioffset = INTVAL (offset); | |
ca7fd9cd | 2057 | do |
998d7deb | 2058 | { |
44de5aeb | 2059 | tree offset = component_ref_field_offset (x); |
998d7deb RH |
2060 | tree field = TREE_OPERAND (x, 1); |
2061 | ||
44de5aeb | 2062 | if (! host_integerp (offset, 1)) |
998d7deb | 2063 | return NULL_RTX; |
44de5aeb | 2064 | ioffset += (tree_low_cst (offset, 1) |
998d7deb RH |
2065 | + (tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1) |
2066 | / BITS_PER_UNIT)); | |
2067 | ||
2068 | x = TREE_OPERAND (x, 0); | |
2069 | } | |
2070 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
2071 | ||
2072 | return GEN_INT (ioffset); | |
2073 | } | |
2074 | ||
95bd1dd7 | 2075 | /* Return nonzero if we can determine the exprs corresponding to memrefs |
a4311dfe RK |
2076 | X and Y and they do not overlap. */ |
2077 | ||
2e4e39f6 | 2078 | int |
4f588890 | 2079 | nonoverlapping_memrefs_p (const_rtx x, const_rtx y) |
a4311dfe | 2080 | { |
998d7deb | 2081 | tree exprx = MEM_EXPR (x), expry = MEM_EXPR (y); |
a4311dfe RK |
2082 | rtx rtlx, rtly; |
2083 | rtx basex, basey; | |
998d7deb | 2084 | rtx moffsetx, moffsety; |
a4311dfe RK |
2085 | HOST_WIDE_INT offsetx = 0, offsety = 0, sizex, sizey, tem; |
2086 | ||
998d7deb RH |
2087 | /* Unless both have exprs, we can't tell anything. */ |
2088 | if (exprx == 0 || expry == 0) | |
2089 | return 0; | |
c22cacf3 | 2090 | |
998d7deb RH |
2091 | /* If both are field references, we may be able to determine something. */ |
2092 | if (TREE_CODE (exprx) == COMPONENT_REF | |
2093 | && TREE_CODE (expry) == COMPONENT_REF | |
2094 | && nonoverlapping_component_refs_p (exprx, expry)) | |
2095 | return 1; | |
2096 | ||
c22cacf3 | 2097 | |
998d7deb RH |
2098 | /* If the field reference test failed, look at the DECLs involved. */ |
2099 | moffsetx = MEM_OFFSET (x); | |
2100 | if (TREE_CODE (exprx) == COMPONENT_REF) | |
2101 | { | |
ea900239 DB |
2102 | if (TREE_CODE (expry) == VAR_DECL |
2103 | && POINTER_TYPE_P (TREE_TYPE (expry))) | |
2104 | { | |
2105 | tree field = TREE_OPERAND (exprx, 1); | |
2106 | tree fieldcontext = DECL_FIELD_CONTEXT (field); | |
2107 | if (ipa_type_escape_field_does_not_clobber_p (fieldcontext, | |
2108 | TREE_TYPE (field))) | |
c22cacf3 | 2109 | return 1; |
ea900239 DB |
2110 | } |
2111 | { | |
2112 | tree t = decl_for_component_ref (exprx); | |
2113 | if (! t) | |
2114 | return 0; | |
2115 | moffsetx = adjust_offset_for_component_ref (exprx, moffsetx); | |
2116 | exprx = t; | |
2117 | } | |
998d7deb | 2118 | } |
1b096a0a | 2119 | else if (INDIRECT_REF_P (exprx)) |
c67a1cf6 RH |
2120 | { |
2121 | exprx = TREE_OPERAND (exprx, 0); | |
2122 | if (flag_argument_noalias < 2 | |
2123 | || TREE_CODE (exprx) != PARM_DECL) | |
2124 | return 0; | |
2125 | } | |
2126 | ||
998d7deb RH |
2127 | moffsety = MEM_OFFSET (y); |
2128 | if (TREE_CODE (expry) == COMPONENT_REF) | |
2129 | { | |
ea900239 DB |
2130 | if (TREE_CODE (exprx) == VAR_DECL |
2131 | && POINTER_TYPE_P (TREE_TYPE (exprx))) | |
2132 | { | |
2133 | tree field = TREE_OPERAND (expry, 1); | |
2134 | tree fieldcontext = DECL_FIELD_CONTEXT (field); | |
2135 | if (ipa_type_escape_field_does_not_clobber_p (fieldcontext, | |
2136 | TREE_TYPE (field))) | |
c22cacf3 | 2137 | return 1; |
ea900239 DB |
2138 | } |
2139 | { | |
2140 | tree t = decl_for_component_ref (expry); | |
2141 | if (! t) | |
2142 | return 0; | |
2143 | moffsety = adjust_offset_for_component_ref (expry, moffsety); | |
2144 | expry = t; | |
2145 | } | |
998d7deb | 2146 | } |
1b096a0a | 2147 | else if (INDIRECT_REF_P (expry)) |
c67a1cf6 RH |
2148 | { |
2149 | expry = TREE_OPERAND (expry, 0); | |
2150 | if (flag_argument_noalias < 2 | |
2151 | || TREE_CODE (expry) != PARM_DECL) | |
2152 | return 0; | |
2153 | } | |
998d7deb RH |
2154 | |
2155 | if (! DECL_P (exprx) || ! DECL_P (expry)) | |
a4311dfe RK |
2156 | return 0; |
2157 | ||
998d7deb RH |
2158 | rtlx = DECL_RTL (exprx); |
2159 | rtly = DECL_RTL (expry); | |
a4311dfe | 2160 | |
1edcd60b RK |
2161 | /* If either RTL is not a MEM, it must be a REG or CONCAT, meaning they |
2162 | can't overlap unless they are the same because we never reuse that part | |
2163 | of the stack frame used for locals for spilled pseudos. */ | |
3c0cb5de | 2164 | if ((!MEM_P (rtlx) || !MEM_P (rtly)) |
1edcd60b | 2165 | && ! rtx_equal_p (rtlx, rtly)) |
a4311dfe RK |
2166 | return 1; |
2167 | ||
2168 | /* Get the base and offsets of both decls. If either is a register, we | |
2169 | know both are and are the same, so use that as the base. The only | |
2170 | we can avoid overlap is if we can deduce that they are nonoverlapping | |
2171 | pieces of that decl, which is very rare. */ | |
3c0cb5de | 2172 | basex = MEM_P (rtlx) ? XEXP (rtlx, 0) : rtlx; |
481683e1 | 2173 | if (GET_CODE (basex) == PLUS && CONST_INT_P (XEXP (basex, 1))) |
a4311dfe RK |
2174 | offsetx = INTVAL (XEXP (basex, 1)), basex = XEXP (basex, 0); |
2175 | ||
3c0cb5de | 2176 | basey = MEM_P (rtly) ? XEXP (rtly, 0) : rtly; |
481683e1 | 2177 | if (GET_CODE (basey) == PLUS && CONST_INT_P (XEXP (basey, 1))) |
a4311dfe RK |
2178 | offsety = INTVAL (XEXP (basey, 1)), basey = XEXP (basey, 0); |
2179 | ||
d746694a | 2180 | /* If the bases are different, we know they do not overlap if both |
ca7fd9cd | 2181 | are constants or if one is a constant and the other a pointer into the |
d746694a RK |
2182 | stack frame. Otherwise a different base means we can't tell if they |
2183 | overlap or not. */ | |
2184 | if (! rtx_equal_p (basex, basey)) | |
ca7fd9cd KH |
2185 | return ((CONSTANT_P (basex) && CONSTANT_P (basey)) |
2186 | || (CONSTANT_P (basex) && REG_P (basey) | |
2187 | && REGNO_PTR_FRAME_P (REGNO (basey))) | |
2188 | || (CONSTANT_P (basey) && REG_P (basex) | |
2189 | && REGNO_PTR_FRAME_P (REGNO (basex)))); | |
a4311dfe | 2190 | |
3c0cb5de | 2191 | sizex = (!MEM_P (rtlx) ? (int) GET_MODE_SIZE (GET_MODE (rtlx)) |
a4311dfe RK |
2192 | : MEM_SIZE (rtlx) ? INTVAL (MEM_SIZE (rtlx)) |
2193 | : -1); | |
3c0cb5de | 2194 | sizey = (!MEM_P (rtly) ? (int) GET_MODE_SIZE (GET_MODE (rtly)) |
a4311dfe RK |
2195 | : MEM_SIZE (rtly) ? INTVAL (MEM_SIZE (rtly)) : |
2196 | -1); | |
2197 | ||
0af5bc3e RK |
2198 | /* If we have an offset for either memref, it can update the values computed |
2199 | above. */ | |
998d7deb RH |
2200 | if (moffsetx) |
2201 | offsetx += INTVAL (moffsetx), sizex -= INTVAL (moffsetx); | |
2202 | if (moffsety) | |
2203 | offsety += INTVAL (moffsety), sizey -= INTVAL (moffsety); | |
a4311dfe | 2204 | |
0af5bc3e | 2205 | /* If a memref has both a size and an offset, we can use the smaller size. |
efc981bb | 2206 | We can't do this if the offset isn't known because we must view this |
0af5bc3e | 2207 | memref as being anywhere inside the DECL's MEM. */ |
998d7deb | 2208 | if (MEM_SIZE (x) && moffsetx) |
a4311dfe | 2209 | sizex = INTVAL (MEM_SIZE (x)); |
998d7deb | 2210 | if (MEM_SIZE (y) && moffsety) |
a4311dfe RK |
2211 | sizey = INTVAL (MEM_SIZE (y)); |
2212 | ||
2213 | /* Put the values of the memref with the lower offset in X's values. */ | |
2214 | if (offsetx > offsety) | |
2215 | { | |
2216 | tem = offsetx, offsetx = offsety, offsety = tem; | |
2217 | tem = sizex, sizex = sizey, sizey = tem; | |
2218 | } | |
2219 | ||
2220 | /* If we don't know the size of the lower-offset value, we can't tell | |
2221 | if they conflict. Otherwise, we do the test. */ | |
a6f7c915 | 2222 | return sizex >= 0 && offsety >= offsetx + sizex; |
a4311dfe RK |
2223 | } |
2224 | ||
9ae8ffe7 JL |
2225 | /* True dependence: X is read after store in MEM takes place. */ |
2226 | ||
2227 | int | |
4f588890 KG |
2228 | true_dependence (const_rtx mem, enum machine_mode mem_mode, const_rtx x, |
2229 | bool (*varies) (const_rtx, bool)) | |
9ae8ffe7 | 2230 | { |
b3694847 | 2231 | rtx x_addr, mem_addr; |
49982682 | 2232 | rtx base; |
9ae8ffe7 JL |
2233 | |
2234 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) | |
2235 | return 1; | |
2236 | ||
c4484b8f | 2237 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
ac3768f6 | 2238 | This is used in epilogue deallocation functions, and in cselib. */ |
c4484b8f RH |
2239 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) |
2240 | return 1; | |
2241 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
2242 | return 1; | |
9cd9e512 RH |
2243 | if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER |
2244 | || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER) | |
2245 | return 1; | |
c4484b8f | 2246 | |
41472af8 MM |
2247 | if (DIFFERENT_ALIAS_SETS_P (x, mem)) |
2248 | return 0; | |
2249 | ||
389fdba0 RH |
2250 | /* Read-only memory is by definition never modified, and therefore can't |
2251 | conflict with anything. We don't expect to find read-only set on MEM, | |
41806d92 | 2252 | but stupid user tricks can produce them, so don't die. */ |
389fdba0 | 2253 | if (MEM_READONLY_P (x)) |
9ae8ffe7 JL |
2254 | return 0; |
2255 | ||
a4311dfe RK |
2256 | if (nonoverlapping_memrefs_p (mem, x)) |
2257 | return 0; | |
2258 | ||
56ee9281 RH |
2259 | if (mem_mode == VOIDmode) |
2260 | mem_mode = GET_MODE (mem); | |
2261 | ||
eab5c70a BS |
2262 | x_addr = get_addr (XEXP (x, 0)); |
2263 | mem_addr = get_addr (XEXP (mem, 0)); | |
2264 | ||
55efb413 JW |
2265 | base = find_base_term (x_addr); |
2266 | if (base && (GET_CODE (base) == LABEL_REF | |
2267 | || (GET_CODE (base) == SYMBOL_REF | |
2268 | && CONSTANT_POOL_ADDRESS_P (base)))) | |
2269 | return 0; | |
2270 | ||
eab5c70a | 2271 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), mem_mode)) |
1c72c7f6 JC |
2272 | return 0; |
2273 | ||
eab5c70a BS |
2274 | x_addr = canon_rtx (x_addr); |
2275 | mem_addr = canon_rtx (mem_addr); | |
6e73e666 | 2276 | |
0211b6ab JW |
2277 | if (! memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr, |
2278 | SIZE_FOR_MODE (x), x_addr, 0)) | |
2279 | return 0; | |
2280 | ||
c6df88cb | 2281 | if (aliases_everything_p (x)) |
0211b6ab JW |
2282 | return 1; |
2283 | ||
f5143c46 | 2284 | /* We cannot use aliases_everything_p to test MEM, since we must look |
c6df88cb MM |
2285 | at MEM_MODE, rather than GET_MODE (MEM). */ |
2286 | if (mem_mode == QImode || GET_CODE (mem_addr) == AND) | |
a13d4ebf AM |
2287 | return 1; |
2288 | ||
2289 | /* In true_dependence we also allow BLKmode to alias anything. Why | |
2290 | don't we do this in anti_dependence and output_dependence? */ | |
2291 | if (mem_mode == BLKmode || GET_MODE (x) == BLKmode) | |
2292 | return 1; | |
2293 | ||
55b34b5f RG |
2294 | if (fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, varies)) |
2295 | return 0; | |
2296 | ||
2297 | return rtx_refs_may_alias_p (x, mem, true); | |
a13d4ebf AM |
2298 | } |
2299 | ||
2300 | /* Canonical true dependence: X is read after store in MEM takes place. | |
ca7fd9cd KH |
2301 | Variant of true_dependence which assumes MEM has already been |
2302 | canonicalized (hence we no longer do that here). | |
2303 | The mem_addr argument has been added, since true_dependence computed | |
6216f94e JJ |
2304 | this value prior to canonicalizing. |
2305 | If x_addr is non-NULL, it is used in preference of XEXP (x, 0). */ | |
a13d4ebf AM |
2306 | |
2307 | int | |
4f588890 | 2308 | canon_true_dependence (const_rtx mem, enum machine_mode mem_mode, rtx mem_addr, |
6216f94e | 2309 | const_rtx x, rtx x_addr, bool (*varies) (const_rtx, bool)) |
a13d4ebf | 2310 | { |
a13d4ebf AM |
2311 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) |
2312 | return 1; | |
2313 | ||
0fe854a7 RH |
2314 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
2315 | This is used in epilogue deallocation functions. */ | |
2316 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) | |
2317 | return 1; | |
2318 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
2319 | return 1; | |
9cd9e512 RH |
2320 | if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER |
2321 | || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER) | |
2322 | return 1; | |
0fe854a7 | 2323 | |
a13d4ebf AM |
2324 | if (DIFFERENT_ALIAS_SETS_P (x, mem)) |
2325 | return 0; | |
2326 | ||
389fdba0 RH |
2327 | /* Read-only memory is by definition never modified, and therefore can't |
2328 | conflict with anything. We don't expect to find read-only set on MEM, | |
41806d92 | 2329 | but stupid user tricks can produce them, so don't die. */ |
389fdba0 | 2330 | if (MEM_READONLY_P (x)) |
a13d4ebf AM |
2331 | return 0; |
2332 | ||
a4311dfe RK |
2333 | if (nonoverlapping_memrefs_p (x, mem)) |
2334 | return 0; | |
2335 | ||
6216f94e JJ |
2336 | if (! x_addr) |
2337 | x_addr = get_addr (XEXP (x, 0)); | |
a13d4ebf AM |
2338 | |
2339 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), mem_mode)) | |
2340 | return 0; | |
2341 | ||
2342 | x_addr = canon_rtx (x_addr); | |
2343 | if (! memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr, | |
2344 | SIZE_FOR_MODE (x), x_addr, 0)) | |
2345 | return 0; | |
2346 | ||
2347 | if (aliases_everything_p (x)) | |
2348 | return 1; | |
2349 | ||
f5143c46 | 2350 | /* We cannot use aliases_everything_p to test MEM, since we must look |
a13d4ebf AM |
2351 | at MEM_MODE, rather than GET_MODE (MEM). */ |
2352 | if (mem_mode == QImode || GET_CODE (mem_addr) == AND) | |
c6df88cb | 2353 | return 1; |
0211b6ab | 2354 | |
c6df88cb MM |
2355 | /* In true_dependence we also allow BLKmode to alias anything. Why |
2356 | don't we do this in anti_dependence and output_dependence? */ | |
2357 | if (mem_mode == BLKmode || GET_MODE (x) == BLKmode) | |
2358 | return 1; | |
0211b6ab | 2359 | |
55b34b5f RG |
2360 | if (fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, varies)) |
2361 | return 0; | |
2362 | ||
2363 | return rtx_refs_may_alias_p (x, mem, true); | |
9ae8ffe7 JL |
2364 | } |
2365 | ||
da7d8304 | 2366 | /* Returns nonzero if a write to X might alias a previous read from |
389fdba0 | 2367 | (or, if WRITEP is nonzero, a write to) MEM. */ |
9ae8ffe7 | 2368 | |
2c72b78f | 2369 | static int |
4f588890 | 2370 | write_dependence_p (const_rtx mem, const_rtx x, int writep) |
9ae8ffe7 | 2371 | { |
6e73e666 | 2372 | rtx x_addr, mem_addr; |
4f588890 | 2373 | const_rtx fixed_scalar; |
49982682 | 2374 | rtx base; |
6e73e666 | 2375 | |
9ae8ffe7 JL |
2376 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) |
2377 | return 1; | |
2378 | ||
c4484b8f RH |
2379 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
2380 | This is used in epilogue deallocation functions. */ | |
2381 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) | |
2382 | return 1; | |
2383 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
2384 | return 1; | |
9cd9e512 RH |
2385 | if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER |
2386 | || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER) | |
2387 | return 1; | |
c4484b8f | 2388 | |
389fdba0 RH |
2389 | /* A read from read-only memory can't conflict with read-write memory. */ |
2390 | if (!writep && MEM_READONLY_P (mem)) | |
2391 | return 0; | |
55efb413 | 2392 | |
a4311dfe RK |
2393 | if (nonoverlapping_memrefs_p (x, mem)) |
2394 | return 0; | |
2395 | ||
55efb413 JW |
2396 | x_addr = get_addr (XEXP (x, 0)); |
2397 | mem_addr = get_addr (XEXP (mem, 0)); | |
2398 | ||
49982682 JW |
2399 | if (! writep) |
2400 | { | |
55efb413 | 2401 | base = find_base_term (mem_addr); |
49982682 JW |
2402 | if (base && (GET_CODE (base) == LABEL_REF |
2403 | || (GET_CODE (base) == SYMBOL_REF | |
2404 | && CONSTANT_POOL_ADDRESS_P (base)))) | |
2405 | return 0; | |
2406 | } | |
2407 | ||
eab5c70a BS |
2408 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), |
2409 | GET_MODE (mem))) | |
41472af8 MM |
2410 | return 0; |
2411 | ||
eab5c70a BS |
2412 | x_addr = canon_rtx (x_addr); |
2413 | mem_addr = canon_rtx (mem_addr); | |
6e73e666 | 2414 | |
c6df88cb MM |
2415 | if (!memrefs_conflict_p (SIZE_FOR_MODE (mem), mem_addr, |
2416 | SIZE_FOR_MODE (x), x_addr, 0)) | |
2417 | return 0; | |
2418 | ||
ca7fd9cd | 2419 | fixed_scalar |
eab5c70a BS |
2420 | = fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, |
2421 | rtx_addr_varies_p); | |
2422 | ||
55b34b5f RG |
2423 | if ((fixed_scalar == mem && !aliases_everything_p (x)) |
2424 | || (fixed_scalar == x && !aliases_everything_p (mem))) | |
2425 | return 0; | |
2426 | ||
2427 | return rtx_refs_may_alias_p (x, mem, false); | |
c6df88cb MM |
2428 | } |
2429 | ||
2430 | /* Anti dependence: X is written after read in MEM takes place. */ | |
2431 | ||
2432 | int | |
4f588890 | 2433 | anti_dependence (const_rtx mem, const_rtx x) |
c6df88cb | 2434 | { |
389fdba0 | 2435 | return write_dependence_p (mem, x, /*writep=*/0); |
9ae8ffe7 JL |
2436 | } |
2437 | ||
2438 | /* Output dependence: X is written after store in MEM takes place. */ | |
2439 | ||
2440 | int | |
4f588890 | 2441 | output_dependence (const_rtx mem, const_rtx x) |
9ae8ffe7 | 2442 | { |
389fdba0 | 2443 | return write_dependence_p (mem, x, /*writep=*/1); |
9ae8ffe7 | 2444 | } |
c14b9960 | 2445 | \f |
6e73e666 | 2446 | |
6e73e666 | 2447 | void |
b5deb7b6 | 2448 | init_alias_target (void) |
6e73e666 | 2449 | { |
b3694847 | 2450 | int i; |
6e73e666 | 2451 | |
b5deb7b6 SL |
2452 | memset (static_reg_base_value, 0, sizeof static_reg_base_value); |
2453 | ||
6e73e666 JC |
2454 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) |
2455 | /* Check whether this register can hold an incoming pointer | |
2456 | argument. FUNCTION_ARG_REGNO_P tests outgoing register | |
ec5c56db | 2457 | numbers, so translate if necessary due to register windows. */ |
6e73e666 JC |
2458 | if (FUNCTION_ARG_REGNO_P (OUTGOING_REGNO (i)) |
2459 | && HARD_REGNO_MODE_OK (i, Pmode)) | |
bf1660a6 JL |
2460 | static_reg_base_value[i] |
2461 | = gen_rtx_ADDRESS (VOIDmode, gen_rtx_REG (Pmode, i)); | |
2462 | ||
bf1660a6 JL |
2463 | static_reg_base_value[STACK_POINTER_REGNUM] |
2464 | = gen_rtx_ADDRESS (Pmode, stack_pointer_rtx); | |
2465 | static_reg_base_value[ARG_POINTER_REGNUM] | |
2466 | = gen_rtx_ADDRESS (Pmode, arg_pointer_rtx); | |
2467 | static_reg_base_value[FRAME_POINTER_REGNUM] | |
2468 | = gen_rtx_ADDRESS (Pmode, frame_pointer_rtx); | |
2469 | #if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM | |
2470 | static_reg_base_value[HARD_FRAME_POINTER_REGNUM] | |
2471 | = gen_rtx_ADDRESS (Pmode, hard_frame_pointer_rtx); | |
2472 | #endif | |
2473 | } | |
2474 | ||
7b52eede JH |
2475 | /* Set MEMORY_MODIFIED when X modifies DATA (that is assumed |
2476 | to be memory reference. */ | |
2477 | static bool memory_modified; | |
2478 | static void | |
aa317c97 | 2479 | memory_modified_1 (rtx x, const_rtx pat ATTRIBUTE_UNUSED, void *data) |
7b52eede | 2480 | { |
3c0cb5de | 2481 | if (MEM_P (x)) |
7b52eede | 2482 | { |
9678086d | 2483 | if (anti_dependence (x, (const_rtx)data) || output_dependence (x, (const_rtx)data)) |
7b52eede JH |
2484 | memory_modified = true; |
2485 | } | |
2486 | } | |
2487 | ||
2488 | ||
2489 | /* Return true when INSN possibly modify memory contents of MEM | |
454ff5cb | 2490 | (i.e. address can be modified). */ |
7b52eede | 2491 | bool |
9678086d | 2492 | memory_modified_in_insn_p (const_rtx mem, const_rtx insn) |
7b52eede JH |
2493 | { |
2494 | if (!INSN_P (insn)) | |
2495 | return false; | |
2496 | memory_modified = false; | |
aa317c97 | 2497 | note_stores (PATTERN (insn), memory_modified_1, CONST_CAST_RTX(mem)); |
7b52eede JH |
2498 | return memory_modified; |
2499 | } | |
2500 | ||
c13e8210 MM |
2501 | /* Initialize the aliasing machinery. Initialize the REG_KNOWN_VALUE |
2502 | array. */ | |
2503 | ||
9ae8ffe7 | 2504 | void |
4682ae04 | 2505 | init_alias_analysis (void) |
9ae8ffe7 | 2506 | { |
c582d54a | 2507 | unsigned int maxreg = max_reg_num (); |
ea64ef27 | 2508 | int changed, pass; |
b3694847 SS |
2509 | int i; |
2510 | unsigned int ui; | |
2511 | rtx insn; | |
9ae8ffe7 | 2512 | |
0d446150 JH |
2513 | timevar_push (TV_ALIAS_ANALYSIS); |
2514 | ||
bb1acb3e | 2515 | reg_known_value_size = maxreg - FIRST_PSEUDO_REGISTER; |
f883e0a7 KG |
2516 | reg_known_value = GGC_CNEWVEC (rtx, reg_known_value_size); |
2517 | reg_known_equiv_p = XCNEWVEC (bool, reg_known_value_size); | |
9ae8ffe7 | 2518 | |
08c79682 | 2519 | /* If we have memory allocated from the previous run, use it. */ |
c582d54a | 2520 | if (old_reg_base_value) |
08c79682 KH |
2521 | reg_base_value = old_reg_base_value; |
2522 | ||
2523 | if (reg_base_value) | |
2524 | VEC_truncate (rtx, reg_base_value, 0); | |
2525 | ||
a590ac65 | 2526 | VEC_safe_grow_cleared (rtx, gc, reg_base_value, maxreg); |
ac606739 | 2527 | |
5ed6ace5 MD |
2528 | new_reg_base_value = XNEWVEC (rtx, maxreg); |
2529 | reg_seen = XNEWVEC (char, maxreg); | |
ec907dd8 JL |
2530 | |
2531 | /* The basic idea is that each pass through this loop will use the | |
2532 | "constant" information from the previous pass to propagate alias | |
2533 | information through another level of assignments. | |
2534 | ||
2535 | This could get expensive if the assignment chains are long. Maybe | |
2536 | we should throttle the number of iterations, possibly based on | |
6e73e666 | 2537 | the optimization level or flag_expensive_optimizations. |
ec907dd8 JL |
2538 | |
2539 | We could propagate more information in the first pass by making use | |
6fb5fa3c | 2540 | of DF_REG_DEF_COUNT to determine immediately that the alias information |
ea64ef27 JL |
2541 | for a pseudo is "constant". |
2542 | ||
2543 | A program with an uninitialized variable can cause an infinite loop | |
2544 | here. Instead of doing a full dataflow analysis to detect such problems | |
2545 | we just cap the number of iterations for the loop. | |
2546 | ||
2547 | The state of the arrays for the set chain in question does not matter | |
2548 | since the program has undefined behavior. */ | |
6e73e666 | 2549 | |
ea64ef27 | 2550 | pass = 0; |
6e73e666 | 2551 | do |
ec907dd8 JL |
2552 | { |
2553 | /* Assume nothing will change this iteration of the loop. */ | |
2554 | changed = 0; | |
2555 | ||
ec907dd8 JL |
2556 | /* We want to assign the same IDs each iteration of this loop, so |
2557 | start counting from zero each iteration of the loop. */ | |
2558 | unique_id = 0; | |
2559 | ||
f5143c46 | 2560 | /* We're at the start of the function each iteration through the |
ec907dd8 | 2561 | loop, so we're copying arguments. */ |
83bbd9b6 | 2562 | copying_arguments = true; |
9ae8ffe7 | 2563 | |
6e73e666 | 2564 | /* Wipe the potential alias information clean for this pass. */ |
c582d54a | 2565 | memset (new_reg_base_value, 0, maxreg * sizeof (rtx)); |
8072f69c | 2566 | |
6e73e666 | 2567 | /* Wipe the reg_seen array clean. */ |
c582d54a | 2568 | memset (reg_seen, 0, maxreg); |
9ae8ffe7 | 2569 | |
6e73e666 JC |
2570 | /* Mark all hard registers which may contain an address. |
2571 | The stack, frame and argument pointers may contain an address. | |
2572 | An argument register which can hold a Pmode value may contain | |
2573 | an address even if it is not in BASE_REGS. | |
8072f69c | 2574 | |
6e73e666 JC |
2575 | The address expression is VOIDmode for an argument and |
2576 | Pmode for other registers. */ | |
2577 | ||
7f243674 JL |
2578 | memcpy (new_reg_base_value, static_reg_base_value, |
2579 | FIRST_PSEUDO_REGISTER * sizeof (rtx)); | |
6e73e666 | 2580 | |
ec907dd8 JL |
2581 | /* Walk the insns adding values to the new_reg_base_value array. */ |
2582 | for (insn = get_insns (); insn; insn = NEXT_INSN (insn)) | |
9ae8ffe7 | 2583 | { |
2c3c49de | 2584 | if (INSN_P (insn)) |
ec907dd8 | 2585 | { |
6e73e666 | 2586 | rtx note, set; |
efc9bd41 RK |
2587 | |
2588 | #if defined (HAVE_prologue) || defined (HAVE_epilogue) | |
f5143c46 | 2589 | /* The prologue/epilogue insns are not threaded onto the |
657959ca JL |
2590 | insn chain until after reload has completed. Thus, |
2591 | there is no sense wasting time checking if INSN is in | |
2592 | the prologue/epilogue until after reload has completed. */ | |
2593 | if (reload_completed | |
2594 | && prologue_epilogue_contains (insn)) | |
efc9bd41 RK |
2595 | continue; |
2596 | #endif | |
2597 | ||
ec907dd8 | 2598 | /* If this insn has a noalias note, process it, Otherwise, |
c22cacf3 MS |
2599 | scan for sets. A simple set will have no side effects |
2600 | which could change the base value of any other register. */ | |
6e73e666 | 2601 | |
ec907dd8 | 2602 | if (GET_CODE (PATTERN (insn)) == SET |
efc9bd41 RK |
2603 | && REG_NOTES (insn) != 0 |
2604 | && find_reg_note (insn, REG_NOALIAS, NULL_RTX)) | |
84832317 | 2605 | record_set (SET_DEST (PATTERN (insn)), NULL_RTX, NULL); |
ec907dd8 | 2606 | else |
84832317 | 2607 | note_stores (PATTERN (insn), record_set, NULL); |
6e73e666 JC |
2608 | |
2609 | set = single_set (insn); | |
2610 | ||
2611 | if (set != 0 | |
f8cfc6aa | 2612 | && REG_P (SET_DEST (set)) |
fb6754f0 | 2613 | && REGNO (SET_DEST (set)) >= FIRST_PSEUDO_REGISTER) |
6e73e666 | 2614 | { |
fb6754f0 | 2615 | unsigned int regno = REGNO (SET_DEST (set)); |
713f41f9 | 2616 | rtx src = SET_SRC (set); |
bb1acb3e | 2617 | rtx t; |
713f41f9 | 2618 | |
a31830a7 SB |
2619 | note = find_reg_equal_equiv_note (insn); |
2620 | if (note && REG_NOTE_KIND (note) == REG_EQUAL | |
6fb5fa3c | 2621 | && DF_REG_DEF_COUNT (regno) != 1) |
a31830a7 SB |
2622 | note = NULL_RTX; |
2623 | ||
2624 | if (note != NULL_RTX | |
713f41f9 | 2625 | && GET_CODE (XEXP (note, 0)) != EXPR_LIST |
bb2cf916 | 2626 | && ! rtx_varies_p (XEXP (note, 0), 1) |
bb1acb3e RH |
2627 | && ! reg_overlap_mentioned_p (SET_DEST (set), |
2628 | XEXP (note, 0))) | |
713f41f9 | 2629 | { |
bb1acb3e RH |
2630 | set_reg_known_value (regno, XEXP (note, 0)); |
2631 | set_reg_known_equiv_p (regno, | |
2632 | REG_NOTE_KIND (note) == REG_EQUIV); | |
713f41f9 | 2633 | } |
6fb5fa3c | 2634 | else if (DF_REG_DEF_COUNT (regno) == 1 |
713f41f9 | 2635 | && GET_CODE (src) == PLUS |
f8cfc6aa | 2636 | && REG_P (XEXP (src, 0)) |
bb1acb3e | 2637 | && (t = get_reg_known_value (REGNO (XEXP (src, 0)))) |
481683e1 | 2638 | && CONST_INT_P (XEXP (src, 1))) |
713f41f9 | 2639 | { |
bb1acb3e RH |
2640 | t = plus_constant (t, INTVAL (XEXP (src, 1))); |
2641 | set_reg_known_value (regno, t); | |
2642 | set_reg_known_equiv_p (regno, 0); | |
713f41f9 | 2643 | } |
6fb5fa3c | 2644 | else if (DF_REG_DEF_COUNT (regno) == 1 |
713f41f9 BS |
2645 | && ! rtx_varies_p (src, 1)) |
2646 | { | |
bb1acb3e RH |
2647 | set_reg_known_value (regno, src); |
2648 | set_reg_known_equiv_p (regno, 0); | |
713f41f9 | 2649 | } |
6e73e666 | 2650 | } |
ec907dd8 | 2651 | } |
4b4bf941 | 2652 | else if (NOTE_P (insn) |
a38e7aa5 | 2653 | && NOTE_KIND (insn) == NOTE_INSN_FUNCTION_BEG) |
83bbd9b6 | 2654 | copying_arguments = false; |
6e73e666 | 2655 | } |
ec907dd8 | 2656 | |
6e73e666 | 2657 | /* Now propagate values from new_reg_base_value to reg_base_value. */ |
62e5bf5d | 2658 | gcc_assert (maxreg == (unsigned int) max_reg_num ()); |
c22cacf3 | 2659 | |
c582d54a | 2660 | for (ui = 0; ui < maxreg; ui++) |
6e73e666 | 2661 | { |
e51712db | 2662 | if (new_reg_base_value[ui] |
08c79682 | 2663 | && new_reg_base_value[ui] != VEC_index (rtx, reg_base_value, ui) |
c582d54a | 2664 | && ! rtx_equal_p (new_reg_base_value[ui], |
08c79682 | 2665 | VEC_index (rtx, reg_base_value, ui))) |
ec907dd8 | 2666 | { |
08c79682 | 2667 | VEC_replace (rtx, reg_base_value, ui, new_reg_base_value[ui]); |
6e73e666 | 2668 | changed = 1; |
ec907dd8 | 2669 | } |
9ae8ffe7 | 2670 | } |
9ae8ffe7 | 2671 | } |
6e73e666 | 2672 | while (changed && ++pass < MAX_ALIAS_LOOP_PASSES); |
9ae8ffe7 JL |
2673 | |
2674 | /* Fill in the remaining entries. */ | |
bb1acb3e | 2675 | for (i = 0; i < (int)reg_known_value_size; i++) |
9ae8ffe7 | 2676 | if (reg_known_value[i] == 0) |
bb1acb3e | 2677 | reg_known_value[i] = regno_reg_rtx[i + FIRST_PSEUDO_REGISTER]; |
9ae8ffe7 | 2678 | |
e05e2395 MM |
2679 | /* Clean up. */ |
2680 | free (new_reg_base_value); | |
ec907dd8 | 2681 | new_reg_base_value = 0; |
e05e2395 | 2682 | free (reg_seen); |
9ae8ffe7 | 2683 | reg_seen = 0; |
0d446150 | 2684 | timevar_pop (TV_ALIAS_ANALYSIS); |
9ae8ffe7 JL |
2685 | } |
2686 | ||
2687 | void | |
4682ae04 | 2688 | end_alias_analysis (void) |
9ae8ffe7 | 2689 | { |
c582d54a | 2690 | old_reg_base_value = reg_base_value; |
bb1acb3e | 2691 | ggc_free (reg_known_value); |
9ae8ffe7 | 2692 | reg_known_value = 0; |
ac606739 | 2693 | reg_known_value_size = 0; |
bb1acb3e | 2694 | free (reg_known_equiv_p); |
e05e2395 | 2695 | reg_known_equiv_p = 0; |
9ae8ffe7 | 2696 | } |
e2500fed GK |
2697 | |
2698 | #include "gt-alias.h" |