]>
Commit | Line | Data |
---|---|---|
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 | } | |
4c685825 RG |
312 | else if (INTVAL (MEM_OFFSET (mem)) < 0 |
313 | && MEM_EXPR (mem) != get_spill_slot_decl (false)) | |
314 | { | |
315 | /* Negative MEM_OFFSET happens for promoted subregs on bigendian | |
316 | targets. We need to compensate both the size and the offset here, | |
317 | which get_ref_base_and_extent will have done based on the MEM_EXPR | |
318 | already. */ | |
319 | gcc_assert (((INTVAL (MEM_SIZE (mem)) + INTVAL (MEM_OFFSET (mem))) | |
320 | * BITS_PER_UNIT) | |
321 | == ref->size); | |
322 | return true; | |
323 | } | |
55b34b5f RG |
324 | else |
325 | { | |
326 | ref->offset += INTVAL (MEM_OFFSET (mem)) * BITS_PER_UNIT; | |
327 | } | |
328 | ||
329 | /* NULL MEM_SIZE should not really happen with a non-NULL MEM_EXPR, | |
330 | but just play safe here. The size may have been adjusted together | |
331 | with the offset, so we need to take it if it is set and not rely | |
332 | on MEM_EXPR here (which has the size determining parts potentially | |
333 | stripped anyway). We lose precision for max_size which is only | |
334 | available from the remaining MEM_EXPR. */ | |
335 | if (MEM_SIZE (mem) == NULL_RTX) | |
336 | { | |
337 | ref->size = -1; | |
338 | ref->max_size = -1; | |
339 | } | |
340 | else | |
341 | { | |
342 | ref->size = INTVAL (MEM_SIZE (mem)) * BITS_PER_UNIT; | |
343 | } | |
344 | ||
345 | return true; | |
346 | } | |
347 | ||
348 | /* Query the alias-oracle on whether the two memory rtx X and MEM may | |
349 | alias. If TBAA_P is set also apply TBAA. Returns true if the | |
350 | two rtxen may alias, false otherwise. */ | |
351 | ||
352 | static bool | |
353 | rtx_refs_may_alias_p (const_rtx x, const_rtx mem, bool tbaa_p) | |
354 | { | |
355 | ao_ref ref1, ref2; | |
356 | ||
357 | if (!ao_ref_from_mem (&ref1, x) | |
358 | || !ao_ref_from_mem (&ref2, mem)) | |
359 | return true; | |
360 | ||
361 | return refs_may_alias_p_1 (&ref1, &ref2, tbaa_p); | |
362 | } | |
363 | ||
3932261a MM |
364 | /* Returns a pointer to the alias set entry for ALIAS_SET, if there is |
365 | such an entry, or NULL otherwise. */ | |
366 | ||
9ddb66ca | 367 | static inline alias_set_entry |
4862826d | 368 | get_alias_set_entry (alias_set_type alias_set) |
3932261a | 369 | { |
1a5640b4 | 370 | return VEC_index (alias_set_entry, alias_sets, alias_set); |
3932261a MM |
371 | } |
372 | ||
ac3d9668 RK |
373 | /* Returns nonzero if the alias sets for MEM1 and MEM2 are such that |
374 | the two MEMs cannot alias each other. */ | |
3932261a | 375 | |
9ddb66ca | 376 | static inline int |
4f588890 | 377 | mems_in_disjoint_alias_sets_p (const_rtx mem1, const_rtx mem2) |
3932261a | 378 | { |
3932261a MM |
379 | /* Perform a basic sanity check. Namely, that there are no alias sets |
380 | if we're not using strict aliasing. This helps to catch bugs | |
381 | whereby someone uses PUT_CODE, but doesn't clear MEM_ALIAS_SET, or | |
382 | where a MEM is allocated in some way other than by the use of | |
383 | gen_rtx_MEM, and the MEM_ALIAS_SET is not cleared. If we begin to | |
384 | use alias sets to indicate that spilled registers cannot alias each | |
385 | other, we might need to remove this check. */ | |
298e6adc NS |
386 | gcc_assert (flag_strict_aliasing |
387 | || (!MEM_ALIAS_SET (mem1) && !MEM_ALIAS_SET (mem2))); | |
3932261a | 388 | |
1da68f56 RK |
389 | return ! alias_sets_conflict_p (MEM_ALIAS_SET (mem1), MEM_ALIAS_SET (mem2)); |
390 | } | |
3932261a | 391 | |
1da68f56 RK |
392 | /* Insert the NODE into the splay tree given by DATA. Used by |
393 | record_alias_subset via splay_tree_foreach. */ | |
394 | ||
395 | static int | |
4682ae04 | 396 | insert_subset_children (splay_tree_node node, void *data) |
1da68f56 RK |
397 | { |
398 | splay_tree_insert ((splay_tree) data, node->key, node->value); | |
399 | ||
400 | return 0; | |
401 | } | |
402 | ||
c58936b6 DB |
403 | /* Return true if the first alias set is a subset of the second. */ |
404 | ||
405 | bool | |
4862826d | 406 | alias_set_subset_of (alias_set_type set1, alias_set_type set2) |
c58936b6 DB |
407 | { |
408 | alias_set_entry ase; | |
409 | ||
410 | /* Everything is a subset of the "aliases everything" set. */ | |
411 | if (set2 == 0) | |
412 | return true; | |
413 | ||
414 | /* Otherwise, check if set1 is a subset of set2. */ | |
415 | ase = get_alias_set_entry (set2); | |
416 | if (ase != 0 | |
a7a512be RG |
417 | && ((ase->has_zero_child && set1 == 0) |
418 | || splay_tree_lookup (ase->children, | |
419 | (splay_tree_key) set1))) | |
c58936b6 DB |
420 | return true; |
421 | return false; | |
422 | } | |
423 | ||
1da68f56 RK |
424 | /* Return 1 if the two specified alias sets may conflict. */ |
425 | ||
426 | int | |
4862826d | 427 | alias_sets_conflict_p (alias_set_type set1, alias_set_type set2) |
1da68f56 RK |
428 | { |
429 | alias_set_entry ase; | |
430 | ||
836f7794 EB |
431 | /* The easy case. */ |
432 | if (alias_sets_must_conflict_p (set1, set2)) | |
1da68f56 | 433 | return 1; |
3932261a | 434 | |
3bdf5ad1 | 435 | /* See if the first alias set is a subset of the second. */ |
1da68f56 | 436 | ase = get_alias_set_entry (set1); |
2bf105ab RK |
437 | if (ase != 0 |
438 | && (ase->has_zero_child | |
439 | || splay_tree_lookup (ase->children, | |
1da68f56 RK |
440 | (splay_tree_key) set2))) |
441 | return 1; | |
3932261a MM |
442 | |
443 | /* Now do the same, but with the alias sets reversed. */ | |
1da68f56 | 444 | ase = get_alias_set_entry (set2); |
2bf105ab RK |
445 | if (ase != 0 |
446 | && (ase->has_zero_child | |
447 | || splay_tree_lookup (ase->children, | |
1da68f56 RK |
448 | (splay_tree_key) set1))) |
449 | return 1; | |
3932261a | 450 | |
1da68f56 | 451 | /* The two alias sets are distinct and neither one is the |
836f7794 | 452 | child of the other. Therefore, they cannot conflict. */ |
1da68f56 | 453 | return 0; |
3932261a | 454 | } |
5399d643 | 455 | |
71a6fe66 BM |
456 | static int |
457 | walk_mems_2 (rtx *x, rtx mem) | |
458 | { | |
459 | if (MEM_P (*x)) | |
460 | { | |
461 | if (alias_sets_conflict_p (MEM_ALIAS_SET(*x), MEM_ALIAS_SET(mem))) | |
462 | return 1; | |
463 | ||
464 | return -1; | |
465 | } | |
466 | return 0; | |
467 | } | |
468 | ||
469 | static int | |
470 | walk_mems_1 (rtx *x, rtx *pat) | |
471 | { | |
472 | if (MEM_P (*x)) | |
473 | { | |
474 | /* Visit all MEMs in *PAT and check indepedence. */ | |
475 | if (for_each_rtx (pat, (rtx_function) walk_mems_2, *x)) | |
476 | /* Indicate that dependence was determined and stop traversal. */ | |
477 | return 1; | |
478 | ||
479 | return -1; | |
480 | } | |
481 | return 0; | |
482 | } | |
483 | ||
484 | /* Return 1 if two specified instructions have mem expr with conflict alias sets*/ | |
485 | bool | |
486 | insn_alias_sets_conflict_p (rtx insn1, rtx insn2) | |
487 | { | |
488 | /* For each pair of MEMs in INSN1 and INSN2 check their independence. */ | |
489 | return for_each_rtx (&PATTERN (insn1), (rtx_function) walk_mems_1, | |
490 | &PATTERN (insn2)); | |
491 | } | |
492 | ||
836f7794 | 493 | /* Return 1 if the two specified alias sets will always conflict. */ |
5399d643 JW |
494 | |
495 | int | |
4862826d | 496 | alias_sets_must_conflict_p (alias_set_type set1, alias_set_type set2) |
5399d643 JW |
497 | { |
498 | if (set1 == 0 || set2 == 0 || set1 == set2) | |
499 | return 1; | |
500 | ||
501 | return 0; | |
502 | } | |
503 | ||
1da68f56 RK |
504 | /* Return 1 if any MEM object of type T1 will always conflict (using the |
505 | dependency routines in this file) with any MEM object of type T2. | |
506 | This is used when allocating temporary storage. If T1 and/or T2 are | |
507 | NULL_TREE, it means we know nothing about the storage. */ | |
508 | ||
509 | int | |
4682ae04 | 510 | objects_must_conflict_p (tree t1, tree t2) |
1da68f56 | 511 | { |
4862826d | 512 | alias_set_type set1, set2; |
82d610ec | 513 | |
e8ea2809 RK |
514 | /* If neither has a type specified, we don't know if they'll conflict |
515 | because we may be using them to store objects of various types, for | |
516 | example the argument and local variables areas of inlined functions. */ | |
981a4c34 | 517 | if (t1 == 0 && t2 == 0) |
e8ea2809 RK |
518 | return 0; |
519 | ||
1da68f56 RK |
520 | /* If they are the same type, they must conflict. */ |
521 | if (t1 == t2 | |
522 | /* Likewise if both are volatile. */ | |
523 | || (t1 != 0 && TYPE_VOLATILE (t1) && t2 != 0 && TYPE_VOLATILE (t2))) | |
524 | return 1; | |
525 | ||
82d610ec RK |
526 | set1 = t1 ? get_alias_set (t1) : 0; |
527 | set2 = t2 ? get_alias_set (t2) : 0; | |
1da68f56 | 528 | |
836f7794 EB |
529 | /* We can't use alias_sets_conflict_p because we must make sure |
530 | that every subtype of t1 will conflict with every subtype of | |
82d610ec RK |
531 | t2 for which a pair of subobjects of these respective subtypes |
532 | overlaps on the stack. */ | |
836f7794 | 533 | return alias_sets_must_conflict_p (set1, set2); |
1da68f56 RK |
534 | } |
535 | \f | |
2039d7aa RH |
536 | /* Return true if all nested component references handled by |
537 | get_inner_reference in T are such that we should use the alias set | |
538 | provided by the object at the heart of T. | |
539 | ||
540 | This is true for non-addressable components (which don't have their | |
541 | own alias set), as well as components of objects in alias set zero. | |
542 | This later point is a special case wherein we wish to override the | |
543 | alias set used by the component, but we don't have per-FIELD_DECL | |
544 | assignable alias sets. */ | |
545 | ||
546 | bool | |
22ea9ec0 | 547 | component_uses_parent_alias_set (const_tree t) |
6e24b709 | 548 | { |
afe84921 RH |
549 | while (1) |
550 | { | |
2039d7aa | 551 | /* If we're at the end, it vacuously uses its own alias set. */ |
afe84921 | 552 | if (!handled_component_p (t)) |
2039d7aa | 553 | return false; |
afe84921 RH |
554 | |
555 | switch (TREE_CODE (t)) | |
556 | { | |
557 | case COMPONENT_REF: | |
558 | if (DECL_NONADDRESSABLE_P (TREE_OPERAND (t, 1))) | |
2039d7aa | 559 | return true; |
afe84921 RH |
560 | break; |
561 | ||
562 | case ARRAY_REF: | |
563 | case ARRAY_RANGE_REF: | |
564 | if (TYPE_NONALIASED_COMPONENT (TREE_TYPE (TREE_OPERAND (t, 0)))) | |
2039d7aa | 565 | return true; |
afe84921 RH |
566 | break; |
567 | ||
568 | case REALPART_EXPR: | |
569 | case IMAGPART_EXPR: | |
570 | break; | |
571 | ||
572 | default: | |
573 | /* Bitfields and casts are never addressable. */ | |
2039d7aa | 574 | return true; |
afe84921 RH |
575 | } |
576 | ||
577 | t = TREE_OPERAND (t, 0); | |
2039d7aa RH |
578 | if (get_alias_set (TREE_TYPE (t)) == 0) |
579 | return true; | |
afe84921 | 580 | } |
6e24b709 RK |
581 | } |
582 | ||
5006671f RG |
583 | /* Return the alias set for the memory pointed to by T, which may be |
584 | either a type or an expression. Return -1 if there is nothing | |
585 | special about dereferencing T. */ | |
586 | ||
587 | static alias_set_type | |
588 | get_deref_alias_set_1 (tree t) | |
589 | { | |
590 | /* If we're not doing any alias analysis, just assume everything | |
591 | aliases everything else. */ | |
592 | if (!flag_strict_aliasing) | |
593 | return 0; | |
594 | ||
5b21f0f3 | 595 | /* All we care about is the type. */ |
5006671f | 596 | if (! TYPE_P (t)) |
5b21f0f3 | 597 | t = TREE_TYPE (t); |
5006671f RG |
598 | |
599 | /* If we have an INDIRECT_REF via a void pointer, we don't | |
600 | know anything about what that might alias. Likewise if the | |
601 | pointer is marked that way. */ | |
602 | if (TREE_CODE (TREE_TYPE (t)) == VOID_TYPE | |
603 | || TYPE_REF_CAN_ALIAS_ALL (t)) | |
604 | return 0; | |
605 | ||
606 | return -1; | |
607 | } | |
608 | ||
609 | /* Return the alias set for the memory pointed to by T, which may be | |
610 | either a type or an expression. */ | |
611 | ||
612 | alias_set_type | |
613 | get_deref_alias_set (tree t) | |
614 | { | |
615 | alias_set_type set = get_deref_alias_set_1 (t); | |
616 | ||
617 | /* Fall back to the alias-set of the pointed-to type. */ | |
618 | if (set == -1) | |
619 | { | |
620 | if (! TYPE_P (t)) | |
621 | t = TREE_TYPE (t); | |
622 | set = get_alias_set (TREE_TYPE (t)); | |
623 | } | |
624 | ||
625 | return set; | |
626 | } | |
627 | ||
3bdf5ad1 RK |
628 | /* Return the alias set for T, which may be either a type or an |
629 | expression. Call language-specific routine for help, if needed. */ | |
630 | ||
4862826d | 631 | alias_set_type |
4682ae04 | 632 | get_alias_set (tree t) |
3bdf5ad1 | 633 | { |
4862826d | 634 | alias_set_type set; |
3bdf5ad1 RK |
635 | |
636 | /* If we're not doing any alias analysis, just assume everything | |
637 | aliases everything else. Also return 0 if this or its type is | |
638 | an error. */ | |
639 | if (! flag_strict_aliasing || t == error_mark_node | |
640 | || (! TYPE_P (t) | |
641 | && (TREE_TYPE (t) == 0 || TREE_TYPE (t) == error_mark_node))) | |
642 | return 0; | |
643 | ||
644 | /* We can be passed either an expression or a type. This and the | |
f47e9b4e RK |
645 | language-specific routine may make mutually-recursive calls to each other |
646 | to figure out what to do. At each juncture, we see if this is a tree | |
647 | that the language may need to handle specially. First handle things that | |
738cc472 | 648 | aren't types. */ |
f824e5c3 | 649 | if (! TYPE_P (t)) |
3bdf5ad1 | 650 | { |
738cc472 | 651 | tree inner = t; |
738cc472 | 652 | |
8ac61af7 RK |
653 | /* Remove any nops, then give the language a chance to do |
654 | something with this tree before we look at it. */ | |
655 | STRIP_NOPS (t); | |
ae2bcd98 | 656 | set = lang_hooks.get_alias_set (t); |
8ac61af7 RK |
657 | if (set != -1) |
658 | return set; | |
659 | ||
738cc472 | 660 | /* First see if the actual object referenced is an INDIRECT_REF from a |
6fce44af RK |
661 | restrict-qualified pointer or a "void *". */ |
662 | while (handled_component_p (inner)) | |
738cc472 | 663 | { |
6fce44af | 664 | inner = TREE_OPERAND (inner, 0); |
8ac61af7 | 665 | STRIP_NOPS (inner); |
738cc472 RK |
666 | } |
667 | ||
1b096a0a | 668 | if (INDIRECT_REF_P (inner)) |
738cc472 | 669 | { |
5006671f RG |
670 | set = get_deref_alias_set_1 (TREE_OPERAND (inner, 0)); |
671 | if (set != -1) | |
672 | return set; | |
738cc472 RK |
673 | } |
674 | ||
675 | /* Otherwise, pick up the outermost object that we could have a pointer | |
6fce44af | 676 | to, processing conversions as above. */ |
2039d7aa | 677 | while (component_uses_parent_alias_set (t)) |
f47e9b4e | 678 | { |
6fce44af | 679 | t = TREE_OPERAND (t, 0); |
8ac61af7 RK |
680 | STRIP_NOPS (t); |
681 | } | |
f824e5c3 | 682 | |
738cc472 RK |
683 | /* If we've already determined the alias set for a decl, just return |
684 | it. This is necessary for C++ anonymous unions, whose component | |
685 | variables don't look like union members (boo!). */ | |
5755cd38 | 686 | if (TREE_CODE (t) == VAR_DECL |
3c0cb5de | 687 | && DECL_RTL_SET_P (t) && MEM_P (DECL_RTL (t))) |
5755cd38 JM |
688 | return MEM_ALIAS_SET (DECL_RTL (t)); |
689 | ||
f824e5c3 RK |
690 | /* Now all we care about is the type. */ |
691 | t = TREE_TYPE (t); | |
3bdf5ad1 RK |
692 | } |
693 | ||
3bdf5ad1 | 694 | /* Variant qualifiers don't affect the alias set, so get the main |
daad0278 | 695 | variant. */ |
3bdf5ad1 | 696 | t = TYPE_MAIN_VARIANT (t); |
daad0278 RG |
697 | |
698 | /* Always use the canonical type as well. If this is a type that | |
699 | requires structural comparisons to identify compatible types | |
700 | use alias set zero. */ | |
701 | if (TYPE_STRUCTURAL_EQUALITY_P (t)) | |
702 | return 0; | |
703 | t = TYPE_CANONICAL (t); | |
704 | /* Canonical types shouldn't form a tree nor should the canonical | |
705 | type require structural equality checks. */ | |
706 | gcc_assert (!TYPE_STRUCTURAL_EQUALITY_P (t) && TYPE_CANONICAL (t) == t); | |
707 | ||
708 | /* If this is a type with a known alias set, return it. */ | |
738cc472 | 709 | if (TYPE_ALIAS_SET_KNOWN_P (t)) |
3bdf5ad1 RK |
710 | return TYPE_ALIAS_SET (t); |
711 | ||
36784d0e RG |
712 | /* We don't want to set TYPE_ALIAS_SET for incomplete types. */ |
713 | if (!COMPLETE_TYPE_P (t)) | |
714 | { | |
715 | /* For arrays with unknown size the conservative answer is the | |
716 | alias set of the element type. */ | |
717 | if (TREE_CODE (t) == ARRAY_TYPE) | |
718 | return get_alias_set (TREE_TYPE (t)); | |
719 | ||
720 | /* But return zero as a conservative answer for incomplete types. */ | |
721 | return 0; | |
722 | } | |
723 | ||
3bdf5ad1 | 724 | /* See if the language has special handling for this type. */ |
ae2bcd98 | 725 | set = lang_hooks.get_alias_set (t); |
8ac61af7 | 726 | if (set != -1) |
738cc472 | 727 | return set; |
2bf105ab | 728 | |
3bdf5ad1 RK |
729 | /* There are no objects of FUNCTION_TYPE, so there's no point in |
730 | using up an alias set for them. (There are, of course, pointers | |
731 | and references to functions, but that's different.) */ | |
e11e491d RG |
732 | else if (TREE_CODE (t) == FUNCTION_TYPE |
733 | || TREE_CODE (t) == METHOD_TYPE) | |
3bdf5ad1 | 734 | set = 0; |
74d86f4f RH |
735 | |
736 | /* Unless the language specifies otherwise, let vector types alias | |
737 | their components. This avoids some nasty type punning issues in | |
738 | normal usage. And indeed lets vectors be treated more like an | |
739 | array slice. */ | |
740 | else if (TREE_CODE (t) == VECTOR_TYPE) | |
741 | set = get_alias_set (TREE_TYPE (t)); | |
742 | ||
4653cae5 RG |
743 | /* Unless the language specifies otherwise, treat array types the |
744 | same as their components. This avoids the asymmetry we get | |
745 | through recording the components. Consider accessing a | |
746 | character(kind=1) through a reference to a character(kind=1)[1:1]. | |
747 | Or consider if we want to assign integer(kind=4)[0:D.1387] and | |
748 | integer(kind=4)[4] the same alias set or not. | |
749 | Just be pragmatic here and make sure the array and its element | |
750 | type get the same alias set assigned. */ | |
751 | else if (TREE_CODE (t) == ARRAY_TYPE | |
752 | && !TYPE_NONALIASED_COMPONENT (t)) | |
753 | set = get_alias_set (TREE_TYPE (t)); | |
754 | ||
3bdf5ad1 RK |
755 | else |
756 | /* Otherwise make a new alias set for this type. */ | |
757 | set = new_alias_set (); | |
758 | ||
759 | TYPE_ALIAS_SET (t) = set; | |
2bf105ab RK |
760 | |
761 | /* If this is an aggregate type, we must record any component aliasing | |
762 | information. */ | |
1d79fd2c | 763 | if (AGGREGATE_TYPE_P (t) || TREE_CODE (t) == COMPLEX_TYPE) |
2bf105ab RK |
764 | record_component_aliases (t); |
765 | ||
3bdf5ad1 RK |
766 | return set; |
767 | } | |
768 | ||
769 | /* Return a brand-new alias set. */ | |
770 | ||
4862826d | 771 | alias_set_type |
4682ae04 | 772 | new_alias_set (void) |
3bdf5ad1 | 773 | { |
3bdf5ad1 | 774 | if (flag_strict_aliasing) |
9ddb66ca | 775 | { |
1a5640b4 KH |
776 | if (alias_sets == 0) |
777 | VEC_safe_push (alias_set_entry, gc, alias_sets, 0); | |
778 | VEC_safe_push (alias_set_entry, gc, alias_sets, 0); | |
779 | return VEC_length (alias_set_entry, alias_sets) - 1; | |
9ddb66ca | 780 | } |
3bdf5ad1 RK |
781 | else |
782 | return 0; | |
783 | } | |
3932261a | 784 | |
01d28c3f JM |
785 | /* Indicate that things in SUBSET can alias things in SUPERSET, but that |
786 | not everything that aliases SUPERSET also aliases SUBSET. For example, | |
787 | in C, a store to an `int' can alias a load of a structure containing an | |
788 | `int', and vice versa. But it can't alias a load of a 'double' member | |
789 | of the same structure. Here, the structure would be the SUPERSET and | |
790 | `int' the SUBSET. This relationship is also described in the comment at | |
791 | the beginning of this file. | |
792 | ||
793 | This function should be called only once per SUPERSET/SUBSET pair. | |
3932261a MM |
794 | |
795 | It is illegal for SUPERSET to be zero; everything is implicitly a | |
796 | subset of alias set zero. */ | |
797 | ||
794511d2 | 798 | void |
4862826d | 799 | record_alias_subset (alias_set_type superset, alias_set_type subset) |
3932261a MM |
800 | { |
801 | alias_set_entry superset_entry; | |
802 | alias_set_entry subset_entry; | |
803 | ||
f47e9b4e RK |
804 | /* It is possible in complex type situations for both sets to be the same, |
805 | in which case we can ignore this operation. */ | |
806 | if (superset == subset) | |
807 | return; | |
808 | ||
298e6adc | 809 | gcc_assert (superset); |
3932261a MM |
810 | |
811 | superset_entry = get_alias_set_entry (superset); | |
ca7fd9cd | 812 | if (superset_entry == 0) |
3932261a MM |
813 | { |
814 | /* Create an entry for the SUPERSET, so that we have a place to | |
815 | attach the SUBSET. */ | |
7e5487a2 | 816 | superset_entry = GGC_NEW (struct alias_set_entry_d); |
3932261a | 817 | superset_entry->alias_set = superset; |
ca7fd9cd | 818 | superset_entry->children |
b604074c | 819 | = splay_tree_new_ggc (splay_tree_compare_ints); |
570eb5c8 | 820 | superset_entry->has_zero_child = 0; |
1a5640b4 | 821 | VEC_replace (alias_set_entry, alias_sets, superset, superset_entry); |
3932261a MM |
822 | } |
823 | ||
2bf105ab RK |
824 | if (subset == 0) |
825 | superset_entry->has_zero_child = 1; | |
826 | else | |
827 | { | |
828 | subset_entry = get_alias_set_entry (subset); | |
829 | /* If there is an entry for the subset, enter all of its children | |
830 | (if they are not already present) as children of the SUPERSET. */ | |
ca7fd9cd | 831 | if (subset_entry) |
2bf105ab RK |
832 | { |
833 | if (subset_entry->has_zero_child) | |
834 | superset_entry->has_zero_child = 1; | |
d4b60170 | 835 | |
2bf105ab RK |
836 | splay_tree_foreach (subset_entry->children, insert_subset_children, |
837 | superset_entry->children); | |
838 | } | |
3932261a | 839 | |
2bf105ab | 840 | /* Enter the SUBSET itself as a child of the SUPERSET. */ |
ca7fd9cd | 841 | splay_tree_insert (superset_entry->children, |
2bf105ab RK |
842 | (splay_tree_key) subset, 0); |
843 | } | |
3932261a MM |
844 | } |
845 | ||
a0c33338 RK |
846 | /* Record that component types of TYPE, if any, are part of that type for |
847 | aliasing purposes. For record types, we only record component types | |
b5487346 EB |
848 | for fields that are not marked non-addressable. For array types, we |
849 | only record the component type if it is not marked non-aliased. */ | |
a0c33338 RK |
850 | |
851 | void | |
4682ae04 | 852 | record_component_aliases (tree type) |
a0c33338 | 853 | { |
4862826d | 854 | alias_set_type superset = get_alias_set (type); |
a0c33338 RK |
855 | tree field; |
856 | ||
857 | if (superset == 0) | |
858 | return; | |
859 | ||
860 | switch (TREE_CODE (type)) | |
861 | { | |
a0c33338 RK |
862 | case RECORD_TYPE: |
863 | case UNION_TYPE: | |
864 | case QUAL_UNION_TYPE: | |
6614fd40 | 865 | /* Recursively record aliases for the base classes, if there are any. */ |
fa743e8c | 866 | if (TYPE_BINFO (type)) |
ca7fd9cd KH |
867 | { |
868 | int i; | |
fa743e8c | 869 | tree binfo, base_binfo; |
c22cacf3 | 870 | |
fa743e8c NS |
871 | for (binfo = TYPE_BINFO (type), i = 0; |
872 | BINFO_BASE_ITERATE (binfo, i, base_binfo); i++) | |
873 | record_alias_subset (superset, | |
874 | get_alias_set (BINFO_TYPE (base_binfo))); | |
ca7fd9cd | 875 | } |
a0c33338 | 876 | for (field = TYPE_FIELDS (type); field != 0; field = TREE_CHAIN (field)) |
b5487346 | 877 | if (TREE_CODE (field) == FIELD_DECL && !DECL_NONADDRESSABLE_P (field)) |
2bf105ab | 878 | record_alias_subset (superset, get_alias_set (TREE_TYPE (field))); |
a0c33338 RK |
879 | break; |
880 | ||
1d79fd2c JW |
881 | case COMPLEX_TYPE: |
882 | record_alias_subset (superset, get_alias_set (TREE_TYPE (type))); | |
883 | break; | |
884 | ||
4653cae5 RG |
885 | /* VECTOR_TYPE and ARRAY_TYPE share the alias set with their |
886 | element type. */ | |
887 | ||
a0c33338 RK |
888 | default: |
889 | break; | |
890 | } | |
891 | } | |
892 | ||
3bdf5ad1 RK |
893 | /* Allocate an alias set for use in storing and reading from the varargs |
894 | spill area. */ | |
895 | ||
4862826d | 896 | static GTY(()) alias_set_type varargs_set = -1; |
f103e34d | 897 | |
4862826d | 898 | alias_set_type |
4682ae04 | 899 | get_varargs_alias_set (void) |
3bdf5ad1 | 900 | { |
cd3ce9b4 JM |
901 | #if 1 |
902 | /* We now lower VA_ARG_EXPR, and there's currently no way to attach the | |
903 | varargs alias set to an INDIRECT_REF (FIXME!), so we can't | |
904 | consistently use the varargs alias set for loads from the varargs | |
905 | area. So don't use it anywhere. */ | |
906 | return 0; | |
907 | #else | |
f103e34d GK |
908 | if (varargs_set == -1) |
909 | varargs_set = new_alias_set (); | |
3bdf5ad1 | 910 | |
f103e34d | 911 | return varargs_set; |
cd3ce9b4 | 912 | #endif |
3bdf5ad1 RK |
913 | } |
914 | ||
915 | /* Likewise, but used for the fixed portions of the frame, e.g., register | |
916 | save areas. */ | |
917 | ||
4862826d | 918 | static GTY(()) alias_set_type frame_set = -1; |
f103e34d | 919 | |
4862826d | 920 | alias_set_type |
4682ae04 | 921 | get_frame_alias_set (void) |
3bdf5ad1 | 922 | { |
f103e34d GK |
923 | if (frame_set == -1) |
924 | frame_set = new_alias_set (); | |
3bdf5ad1 | 925 | |
f103e34d | 926 | return frame_set; |
3bdf5ad1 RK |
927 | } |
928 | ||
2a2c8203 JC |
929 | /* Inside SRC, the source of a SET, find a base address. */ |
930 | ||
9ae8ffe7 | 931 | static rtx |
4682ae04 | 932 | find_base_value (rtx src) |
9ae8ffe7 | 933 | { |
713f41f9 | 934 | unsigned int regno; |
0aacc8ed | 935 | |
53451050 RS |
936 | #if defined (FIND_BASE_TERM) |
937 | /* Try machine-dependent ways to find the base term. */ | |
938 | src = FIND_BASE_TERM (src); | |
939 | #endif | |
940 | ||
9ae8ffe7 JL |
941 | switch (GET_CODE (src)) |
942 | { | |
943 | case SYMBOL_REF: | |
944 | case LABEL_REF: | |
945 | return src; | |
946 | ||
947 | case REG: | |
fb6754f0 | 948 | regno = REGNO (src); |
d4b60170 | 949 | /* At the start of a function, argument registers have known base |
2a2c8203 JC |
950 | values which may be lost later. Returning an ADDRESS |
951 | expression here allows optimization based on argument values | |
952 | even when the argument registers are used for other purposes. */ | |
713f41f9 BS |
953 | if (regno < FIRST_PSEUDO_REGISTER && copying_arguments) |
954 | return new_reg_base_value[regno]; | |
73774bc7 | 955 | |
eaf407a5 | 956 | /* If a pseudo has a known base value, return it. Do not do this |
9b462c42 RH |
957 | for non-fixed hard regs since it can result in a circular |
958 | dependency chain for registers which have values at function entry. | |
eaf407a5 JL |
959 | |
960 | The test above is not sufficient because the scheduler may move | |
961 | a copy out of an arg reg past the NOTE_INSN_FUNCTION_BEGIN. */ | |
9b462c42 | 962 | if ((regno >= FIRST_PSEUDO_REGISTER || fixed_regs[regno]) |
08c79682 | 963 | && regno < VEC_length (rtx, reg_base_value)) |
83bbd9b6 RH |
964 | { |
965 | /* If we're inside init_alias_analysis, use new_reg_base_value | |
966 | to reduce the number of relaxation iterations. */ | |
1afdf91c | 967 | if (new_reg_base_value && new_reg_base_value[regno] |
6fb5fa3c | 968 | && DF_REG_DEF_COUNT (regno) == 1) |
83bbd9b6 RH |
969 | return new_reg_base_value[regno]; |
970 | ||
08c79682 KH |
971 | if (VEC_index (rtx, reg_base_value, regno)) |
972 | return VEC_index (rtx, reg_base_value, regno); | |
83bbd9b6 | 973 | } |
73774bc7 | 974 | |
e3f049a8 | 975 | return 0; |
9ae8ffe7 JL |
976 | |
977 | case MEM: | |
978 | /* Check for an argument passed in memory. Only record in the | |
979 | copying-arguments block; it is too hard to track changes | |
980 | otherwise. */ | |
981 | if (copying_arguments | |
982 | && (XEXP (src, 0) == arg_pointer_rtx | |
983 | || (GET_CODE (XEXP (src, 0)) == PLUS | |
984 | && XEXP (XEXP (src, 0), 0) == arg_pointer_rtx))) | |
38a448ca | 985 | return gen_rtx_ADDRESS (VOIDmode, src); |
9ae8ffe7 JL |
986 | return 0; |
987 | ||
988 | case CONST: | |
989 | src = XEXP (src, 0); | |
990 | if (GET_CODE (src) != PLUS && GET_CODE (src) != MINUS) | |
991 | break; | |
d4b60170 | 992 | |
ec5c56db | 993 | /* ... fall through ... */ |
2a2c8203 | 994 | |
9ae8ffe7 JL |
995 | case PLUS: |
996 | case MINUS: | |
2a2c8203 | 997 | { |
ec907dd8 JL |
998 | rtx temp, src_0 = XEXP (src, 0), src_1 = XEXP (src, 1); |
999 | ||
0134bf2d DE |
1000 | /* If either operand is a REG that is a known pointer, then it |
1001 | is the base. */ | |
1002 | if (REG_P (src_0) && REG_POINTER (src_0)) | |
1003 | return find_base_value (src_0); | |
1004 | if (REG_P (src_1) && REG_POINTER (src_1)) | |
1005 | return find_base_value (src_1); | |
1006 | ||
ec907dd8 JL |
1007 | /* If either operand is a REG, then see if we already have |
1008 | a known value for it. */ | |
0134bf2d | 1009 | if (REG_P (src_0)) |
ec907dd8 JL |
1010 | { |
1011 | temp = find_base_value (src_0); | |
d4b60170 | 1012 | if (temp != 0) |
ec907dd8 JL |
1013 | src_0 = temp; |
1014 | } | |
1015 | ||
0134bf2d | 1016 | if (REG_P (src_1)) |
ec907dd8 JL |
1017 | { |
1018 | temp = find_base_value (src_1); | |
d4b60170 | 1019 | if (temp!= 0) |
ec907dd8 JL |
1020 | src_1 = temp; |
1021 | } | |
2a2c8203 | 1022 | |
0134bf2d DE |
1023 | /* If either base is named object or a special address |
1024 | (like an argument or stack reference), then use it for the | |
1025 | base term. */ | |
1026 | if (src_0 != 0 | |
1027 | && (GET_CODE (src_0) == SYMBOL_REF | |
1028 | || GET_CODE (src_0) == LABEL_REF | |
1029 | || (GET_CODE (src_0) == ADDRESS | |
1030 | && GET_MODE (src_0) != VOIDmode))) | |
1031 | return src_0; | |
1032 | ||
1033 | if (src_1 != 0 | |
1034 | && (GET_CODE (src_1) == SYMBOL_REF | |
1035 | || GET_CODE (src_1) == LABEL_REF | |
1036 | || (GET_CODE (src_1) == ADDRESS | |
1037 | && GET_MODE (src_1) != VOIDmode))) | |
1038 | return src_1; | |
1039 | ||
d4b60170 | 1040 | /* Guess which operand is the base address: |
ec907dd8 JL |
1041 | If either operand is a symbol, then it is the base. If |
1042 | either operand is a CONST_INT, then the other is the base. */ | |
481683e1 | 1043 | if (CONST_INT_P (src_1) || CONSTANT_P (src_0)) |
2a2c8203 | 1044 | return find_base_value (src_0); |
481683e1 | 1045 | else if (CONST_INT_P (src_0) || CONSTANT_P (src_1)) |
ec907dd8 JL |
1046 | return find_base_value (src_1); |
1047 | ||
9ae8ffe7 | 1048 | return 0; |
2a2c8203 JC |
1049 | } |
1050 | ||
1051 | case LO_SUM: | |
1052 | /* The standard form is (lo_sum reg sym) so look only at the | |
1053 | second operand. */ | |
1054 | return find_base_value (XEXP (src, 1)); | |
9ae8ffe7 JL |
1055 | |
1056 | case AND: | |
1057 | /* If the second operand is constant set the base | |
ec5c56db | 1058 | address to the first operand. */ |
481683e1 | 1059 | if (CONST_INT_P (XEXP (src, 1)) && INTVAL (XEXP (src, 1)) != 0) |
2a2c8203 | 1060 | return find_base_value (XEXP (src, 0)); |
9ae8ffe7 JL |
1061 | return 0; |
1062 | ||
61f0131c R |
1063 | case TRUNCATE: |
1064 | if (GET_MODE_SIZE (GET_MODE (src)) < GET_MODE_SIZE (Pmode)) | |
1065 | break; | |
1066 | /* Fall through. */ | |
9ae8ffe7 | 1067 | case HIGH: |
d288e53d DE |
1068 | case PRE_INC: |
1069 | case PRE_DEC: | |
1070 | case POST_INC: | |
1071 | case POST_DEC: | |
1072 | case PRE_MODIFY: | |
1073 | case POST_MODIFY: | |
2a2c8203 | 1074 | return find_base_value (XEXP (src, 0)); |
1d300e19 | 1075 | |
0aacc8ed RK |
1076 | case ZERO_EXTEND: |
1077 | case SIGN_EXTEND: /* used for NT/Alpha pointers */ | |
1078 | { | |
1079 | rtx temp = find_base_value (XEXP (src, 0)); | |
1080 | ||
5ae6cd0d | 1081 | if (temp != 0 && CONSTANT_P (temp)) |
0aacc8ed | 1082 | temp = convert_memory_address (Pmode, temp); |
0aacc8ed RK |
1083 | |
1084 | return temp; | |
1085 | } | |
1086 | ||
1d300e19 KG |
1087 | default: |
1088 | break; | |
9ae8ffe7 JL |
1089 | } |
1090 | ||
1091 | return 0; | |
1092 | } | |
1093 | ||
1094 | /* Called from init_alias_analysis indirectly through note_stores. */ | |
1095 | ||
d4b60170 | 1096 | /* While scanning insns to find base values, reg_seen[N] is nonzero if |
9ae8ffe7 JL |
1097 | register N has been set in this function. */ |
1098 | static char *reg_seen; | |
1099 | ||
13309a5f JC |
1100 | /* Addresses which are known not to alias anything else are identified |
1101 | by a unique integer. */ | |
ec907dd8 JL |
1102 | static int unique_id; |
1103 | ||
2a2c8203 | 1104 | static void |
7bc980e1 | 1105 | record_set (rtx dest, const_rtx set, void *data ATTRIBUTE_UNUSED) |
9ae8ffe7 | 1106 | { |
b3694847 | 1107 | unsigned regno; |
9ae8ffe7 | 1108 | rtx src; |
c28b4e40 | 1109 | int n; |
9ae8ffe7 | 1110 | |
f8cfc6aa | 1111 | if (!REG_P (dest)) |
9ae8ffe7 JL |
1112 | return; |
1113 | ||
fb6754f0 | 1114 | regno = REGNO (dest); |
9ae8ffe7 | 1115 | |
08c79682 | 1116 | gcc_assert (regno < VEC_length (rtx, reg_base_value)); |
ac606739 | 1117 | |
c28b4e40 JW |
1118 | /* If this spans multiple hard registers, then we must indicate that every |
1119 | register has an unusable value. */ | |
1120 | if (regno < FIRST_PSEUDO_REGISTER) | |
66fd46b6 | 1121 | n = hard_regno_nregs[regno][GET_MODE (dest)]; |
c28b4e40 JW |
1122 | else |
1123 | n = 1; | |
1124 | if (n != 1) | |
1125 | { | |
1126 | while (--n >= 0) | |
1127 | { | |
1128 | reg_seen[regno + n] = 1; | |
1129 | new_reg_base_value[regno + n] = 0; | |
1130 | } | |
1131 | return; | |
1132 | } | |
1133 | ||
9ae8ffe7 JL |
1134 | if (set) |
1135 | { | |
1136 | /* A CLOBBER wipes out any old value but does not prevent a previously | |
1137 | unset register from acquiring a base address (i.e. reg_seen is not | |
1138 | set). */ | |
1139 | if (GET_CODE (set) == CLOBBER) | |
1140 | { | |
ec907dd8 | 1141 | new_reg_base_value[regno] = 0; |
9ae8ffe7 JL |
1142 | return; |
1143 | } | |
1144 | src = SET_SRC (set); | |
1145 | } | |
1146 | else | |
1147 | { | |
9ae8ffe7 JL |
1148 | if (reg_seen[regno]) |
1149 | { | |
ec907dd8 | 1150 | new_reg_base_value[regno] = 0; |
9ae8ffe7 JL |
1151 | return; |
1152 | } | |
1153 | reg_seen[regno] = 1; | |
38a448ca RH |
1154 | new_reg_base_value[regno] = gen_rtx_ADDRESS (Pmode, |
1155 | GEN_INT (unique_id++)); | |
9ae8ffe7 JL |
1156 | return; |
1157 | } | |
1158 | ||
5da6f168 RS |
1159 | /* If this is not the first set of REGNO, see whether the new value |
1160 | is related to the old one. There are two cases of interest: | |
1161 | ||
1162 | (1) The register might be assigned an entirely new value | |
1163 | that has the same base term as the original set. | |
1164 | ||
1165 | (2) The set might be a simple self-modification that | |
1166 | cannot change REGNO's base value. | |
1167 | ||
1168 | If neither case holds, reject the original base value as invalid. | |
1169 | Note that the following situation is not detected: | |
1170 | ||
c22cacf3 | 1171 | extern int x, y; int *p = &x; p += (&y-&x); |
5da6f168 | 1172 | |
9ae8ffe7 JL |
1173 | ANSI C does not allow computing the difference of addresses |
1174 | of distinct top level objects. */ | |
5da6f168 RS |
1175 | if (new_reg_base_value[regno] != 0 |
1176 | && find_base_value (src) != new_reg_base_value[regno]) | |
9ae8ffe7 JL |
1177 | switch (GET_CODE (src)) |
1178 | { | |
2a2c8203 | 1179 | case LO_SUM: |
9ae8ffe7 JL |
1180 | case MINUS: |
1181 | if (XEXP (src, 0) != dest && XEXP (src, 1) != dest) | |
ec907dd8 | 1182 | new_reg_base_value[regno] = 0; |
9ae8ffe7 | 1183 | break; |
61f0131c R |
1184 | case PLUS: |
1185 | /* If the value we add in the PLUS is also a valid base value, | |
1186 | this might be the actual base value, and the original value | |
1187 | an index. */ | |
1188 | { | |
1189 | rtx other = NULL_RTX; | |
1190 | ||
1191 | if (XEXP (src, 0) == dest) | |
1192 | other = XEXP (src, 1); | |
1193 | else if (XEXP (src, 1) == dest) | |
1194 | other = XEXP (src, 0); | |
1195 | ||
1196 | if (! other || find_base_value (other)) | |
1197 | new_reg_base_value[regno] = 0; | |
1198 | break; | |
1199 | } | |
9ae8ffe7 | 1200 | case AND: |
481683e1 | 1201 | if (XEXP (src, 0) != dest || !CONST_INT_P (XEXP (src, 1))) |
ec907dd8 | 1202 | new_reg_base_value[regno] = 0; |
9ae8ffe7 | 1203 | break; |
9ae8ffe7 | 1204 | default: |
ec907dd8 | 1205 | new_reg_base_value[regno] = 0; |
9ae8ffe7 JL |
1206 | break; |
1207 | } | |
1208 | /* If this is the first set of a register, record the value. */ | |
1209 | else if ((regno >= FIRST_PSEUDO_REGISTER || ! fixed_regs[regno]) | |
ec907dd8 JL |
1210 | && ! reg_seen[regno] && new_reg_base_value[regno] == 0) |
1211 | new_reg_base_value[regno] = find_base_value (src); | |
9ae8ffe7 JL |
1212 | |
1213 | reg_seen[regno] = 1; | |
1214 | } | |
1215 | ||
bb1acb3e RH |
1216 | /* If a value is known for REGNO, return it. */ |
1217 | ||
c22cacf3 | 1218 | rtx |
bb1acb3e RH |
1219 | get_reg_known_value (unsigned int regno) |
1220 | { | |
1221 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1222 | { | |
1223 | regno -= FIRST_PSEUDO_REGISTER; | |
1224 | if (regno < reg_known_value_size) | |
1225 | return reg_known_value[regno]; | |
1226 | } | |
1227 | return NULL; | |
43fe47ca JW |
1228 | } |
1229 | ||
bb1acb3e RH |
1230 | /* Set it. */ |
1231 | ||
1232 | static void | |
1233 | set_reg_known_value (unsigned int regno, rtx val) | |
1234 | { | |
1235 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1236 | { | |
1237 | regno -= FIRST_PSEUDO_REGISTER; | |
1238 | if (regno < reg_known_value_size) | |
1239 | reg_known_value[regno] = val; | |
1240 | } | |
1241 | } | |
1242 | ||
1243 | /* Similarly for reg_known_equiv_p. */ | |
1244 | ||
1245 | bool | |
1246 | get_reg_known_equiv_p (unsigned int regno) | |
1247 | { | |
1248 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1249 | { | |
1250 | regno -= FIRST_PSEUDO_REGISTER; | |
1251 | if (regno < reg_known_value_size) | |
1252 | return reg_known_equiv_p[regno]; | |
1253 | } | |
1254 | return false; | |
1255 | } | |
1256 | ||
1257 | static void | |
1258 | set_reg_known_equiv_p (unsigned int regno, bool val) | |
1259 | { | |
1260 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1261 | { | |
1262 | regno -= FIRST_PSEUDO_REGISTER; | |
1263 | if (regno < reg_known_value_size) | |
1264 | reg_known_equiv_p[regno] = val; | |
1265 | } | |
1266 | } | |
1267 | ||
1268 | ||
db048faf MM |
1269 | /* Returns a canonical version of X, from the point of view alias |
1270 | analysis. (For example, if X is a MEM whose address is a register, | |
1271 | and the register has a known value (say a SYMBOL_REF), then a MEM | |
1272 | whose address is the SYMBOL_REF is returned.) */ | |
1273 | ||
1274 | rtx | |
4682ae04 | 1275 | canon_rtx (rtx x) |
9ae8ffe7 JL |
1276 | { |
1277 | /* Recursively look for equivalences. */ | |
f8cfc6aa | 1278 | if (REG_P (x) && REGNO (x) >= FIRST_PSEUDO_REGISTER) |
bb1acb3e RH |
1279 | { |
1280 | rtx t = get_reg_known_value (REGNO (x)); | |
1281 | if (t == x) | |
1282 | return x; | |
1283 | if (t) | |
1284 | return canon_rtx (t); | |
1285 | } | |
1286 | ||
1287 | if (GET_CODE (x) == PLUS) | |
9ae8ffe7 JL |
1288 | { |
1289 | rtx x0 = canon_rtx (XEXP (x, 0)); | |
1290 | rtx x1 = canon_rtx (XEXP (x, 1)); | |
1291 | ||
1292 | if (x0 != XEXP (x, 0) || x1 != XEXP (x, 1)) | |
1293 | { | |
481683e1 | 1294 | if (CONST_INT_P (x0)) |
ed8908e7 | 1295 | return plus_constant (x1, INTVAL (x0)); |
481683e1 | 1296 | else if (CONST_INT_P (x1)) |
ed8908e7 | 1297 | return plus_constant (x0, INTVAL (x1)); |
38a448ca | 1298 | return gen_rtx_PLUS (GET_MODE (x), x0, x1); |
9ae8ffe7 JL |
1299 | } |
1300 | } | |
d4b60170 | 1301 | |
9ae8ffe7 JL |
1302 | /* This gives us much better alias analysis when called from |
1303 | the loop optimizer. Note we want to leave the original | |
1304 | MEM alone, but need to return the canonicalized MEM with | |
1305 | all the flags with their original values. */ | |
3c0cb5de | 1306 | else if (MEM_P (x)) |
f1ec5147 | 1307 | x = replace_equiv_address_nv (x, canon_rtx (XEXP (x, 0))); |
d4b60170 | 1308 | |
9ae8ffe7 JL |
1309 | return x; |
1310 | } | |
1311 | ||
1312 | /* Return 1 if X and Y are identical-looking rtx's. | |
45183e03 | 1313 | Expect that X and Y has been already canonicalized. |
9ae8ffe7 JL |
1314 | |
1315 | We use the data in reg_known_value above to see if two registers with | |
1316 | different numbers are, in fact, equivalent. */ | |
1317 | ||
1318 | static int | |
ed7a4b4b | 1319 | rtx_equal_for_memref_p (const_rtx x, const_rtx y) |
9ae8ffe7 | 1320 | { |
b3694847 SS |
1321 | int i; |
1322 | int j; | |
1323 | enum rtx_code code; | |
1324 | const char *fmt; | |
9ae8ffe7 JL |
1325 | |
1326 | if (x == 0 && y == 0) | |
1327 | return 1; | |
1328 | if (x == 0 || y == 0) | |
1329 | return 0; | |
d4b60170 | 1330 | |
9ae8ffe7 JL |
1331 | if (x == y) |
1332 | return 1; | |
1333 | ||
1334 | code = GET_CODE (x); | |
1335 | /* Rtx's of different codes cannot be equal. */ | |
1336 | if (code != GET_CODE (y)) | |
1337 | return 0; | |
1338 | ||
1339 | /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. | |
1340 | (REG:SI x) and (REG:HI x) are NOT equivalent. */ | |
1341 | ||
1342 | if (GET_MODE (x) != GET_MODE (y)) | |
1343 | return 0; | |
1344 | ||
db048faf MM |
1345 | /* Some RTL can be compared without a recursive examination. */ |
1346 | switch (code) | |
1347 | { | |
1348 | case REG: | |
1349 | return REGNO (x) == REGNO (y); | |
1350 | ||
1351 | case LABEL_REF: | |
1352 | return XEXP (x, 0) == XEXP (y, 0); | |
ca7fd9cd | 1353 | |
db048faf MM |
1354 | case SYMBOL_REF: |
1355 | return XSTR (x, 0) == XSTR (y, 0); | |
1356 | ||
40e02b4a | 1357 | case VALUE: |
db048faf MM |
1358 | case CONST_INT: |
1359 | case CONST_DOUBLE: | |
091a3ac7 | 1360 | case CONST_FIXED: |
db048faf MM |
1361 | /* There's no need to compare the contents of CONST_DOUBLEs or |
1362 | CONST_INTs because pointer equality is a good enough | |
1363 | comparison for these nodes. */ | |
1364 | return 0; | |
1365 | ||
db048faf MM |
1366 | default: |
1367 | break; | |
1368 | } | |
9ae8ffe7 | 1369 | |
45183e03 JH |
1370 | /* canon_rtx knows how to handle plus. No need to canonicalize. */ |
1371 | if (code == PLUS) | |
9ae8ffe7 JL |
1372 | return ((rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 0)) |
1373 | && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 1))) | |
1374 | || (rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 1)) | |
1375 | && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 0)))); | |
45183e03 JH |
1376 | /* For commutative operations, the RTX match if the operand match in any |
1377 | order. Also handle the simple binary and unary cases without a loop. */ | |
ec8e098d | 1378 | if (COMMUTATIVE_P (x)) |
45183e03 JH |
1379 | { |
1380 | rtx xop0 = canon_rtx (XEXP (x, 0)); | |
1381 | rtx yop0 = canon_rtx (XEXP (y, 0)); | |
1382 | rtx yop1 = canon_rtx (XEXP (y, 1)); | |
1383 | ||
1384 | return ((rtx_equal_for_memref_p (xop0, yop0) | |
1385 | && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), yop1)) | |
1386 | || (rtx_equal_for_memref_p (xop0, yop1) | |
1387 | && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), yop0))); | |
1388 | } | |
ec8e098d | 1389 | else if (NON_COMMUTATIVE_P (x)) |
45183e03 JH |
1390 | { |
1391 | return (rtx_equal_for_memref_p (canon_rtx (XEXP (x, 0)), | |
4682ae04 | 1392 | canon_rtx (XEXP (y, 0))) |
45183e03 JH |
1393 | && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), |
1394 | canon_rtx (XEXP (y, 1)))); | |
1395 | } | |
ec8e098d | 1396 | else if (UNARY_P (x)) |
45183e03 | 1397 | return rtx_equal_for_memref_p (canon_rtx (XEXP (x, 0)), |
4682ae04 | 1398 | canon_rtx (XEXP (y, 0))); |
9ae8ffe7 JL |
1399 | |
1400 | /* Compare the elements. If any pair of corresponding elements | |
de12be17 JC |
1401 | fail to match, return 0 for the whole things. |
1402 | ||
1403 | Limit cases to types which actually appear in addresses. */ | |
9ae8ffe7 JL |
1404 | |
1405 | fmt = GET_RTX_FORMAT (code); | |
1406 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
1407 | { | |
1408 | switch (fmt[i]) | |
1409 | { | |
9ae8ffe7 JL |
1410 | case 'i': |
1411 | if (XINT (x, i) != XINT (y, i)) | |
1412 | return 0; | |
1413 | break; | |
1414 | ||
9ae8ffe7 JL |
1415 | case 'E': |
1416 | /* Two vectors must have the same length. */ | |
1417 | if (XVECLEN (x, i) != XVECLEN (y, i)) | |
1418 | return 0; | |
1419 | ||
1420 | /* And the corresponding elements must match. */ | |
1421 | for (j = 0; j < XVECLEN (x, i); j++) | |
45183e03 JH |
1422 | if (rtx_equal_for_memref_p (canon_rtx (XVECEXP (x, i, j)), |
1423 | canon_rtx (XVECEXP (y, i, j))) == 0) | |
9ae8ffe7 JL |
1424 | return 0; |
1425 | break; | |
1426 | ||
1427 | case 'e': | |
45183e03 JH |
1428 | if (rtx_equal_for_memref_p (canon_rtx (XEXP (x, i)), |
1429 | canon_rtx (XEXP (y, i))) == 0) | |
9ae8ffe7 JL |
1430 | return 0; |
1431 | break; | |
1432 | ||
3237ac18 AH |
1433 | /* This can happen for asm operands. */ |
1434 | case 's': | |
1435 | if (strcmp (XSTR (x, i), XSTR (y, i))) | |
1436 | return 0; | |
1437 | break; | |
1438 | ||
aee21ba9 JL |
1439 | /* This can happen for an asm which clobbers memory. */ |
1440 | case '0': | |
1441 | break; | |
1442 | ||
9ae8ffe7 JL |
1443 | /* It is believed that rtx's at this level will never |
1444 | contain anything but integers and other rtx's, | |
1445 | except for within LABEL_REFs and SYMBOL_REFs. */ | |
1446 | default: | |
298e6adc | 1447 | gcc_unreachable (); |
9ae8ffe7 JL |
1448 | } |
1449 | } | |
1450 | return 1; | |
1451 | } | |
1452 | ||
94f24ddc | 1453 | rtx |
4682ae04 | 1454 | find_base_term (rtx x) |
9ae8ffe7 | 1455 | { |
eab5c70a BS |
1456 | cselib_val *val; |
1457 | struct elt_loc_list *l; | |
1458 | ||
b949ea8b JW |
1459 | #if defined (FIND_BASE_TERM) |
1460 | /* Try machine-dependent ways to find the base term. */ | |
1461 | x = FIND_BASE_TERM (x); | |
1462 | #endif | |
1463 | ||
9ae8ffe7 JL |
1464 | switch (GET_CODE (x)) |
1465 | { | |
1466 | case REG: | |
1467 | return REG_BASE_VALUE (x); | |
1468 | ||
d288e53d DE |
1469 | case TRUNCATE: |
1470 | if (GET_MODE_SIZE (GET_MODE (x)) < GET_MODE_SIZE (Pmode)) | |
ca7fd9cd | 1471 | return 0; |
d288e53d | 1472 | /* Fall through. */ |
9ae8ffe7 | 1473 | case HIGH: |
6d849a2a JL |
1474 | case PRE_INC: |
1475 | case PRE_DEC: | |
1476 | case POST_INC: | |
1477 | case POST_DEC: | |
d288e53d DE |
1478 | case PRE_MODIFY: |
1479 | case POST_MODIFY: | |
6d849a2a JL |
1480 | return find_base_term (XEXP (x, 0)); |
1481 | ||
1abade85 RK |
1482 | case ZERO_EXTEND: |
1483 | case SIGN_EXTEND: /* Used for Alpha/NT pointers */ | |
1484 | { | |
1485 | rtx temp = find_base_term (XEXP (x, 0)); | |
1486 | ||
5ae6cd0d | 1487 | if (temp != 0 && CONSTANT_P (temp)) |
1abade85 | 1488 | temp = convert_memory_address (Pmode, temp); |
1abade85 RK |
1489 | |
1490 | return temp; | |
1491 | } | |
1492 | ||
eab5c70a BS |
1493 | case VALUE: |
1494 | val = CSELIB_VAL_PTR (x); | |
40e02b4a JH |
1495 | if (!val) |
1496 | return 0; | |
eab5c70a BS |
1497 | for (l = val->locs; l; l = l->next) |
1498 | if ((x = find_base_term (l->loc)) != 0) | |
1499 | return x; | |
1500 | return 0; | |
1501 | ||
023f059b JJ |
1502 | case LO_SUM: |
1503 | /* The standard form is (lo_sum reg sym) so look only at the | |
1504 | second operand. */ | |
1505 | return find_base_term (XEXP (x, 1)); | |
1506 | ||
9ae8ffe7 JL |
1507 | case CONST: |
1508 | x = XEXP (x, 0); | |
1509 | if (GET_CODE (x) != PLUS && GET_CODE (x) != MINUS) | |
1510 | return 0; | |
938d968e | 1511 | /* Fall through. */ |
9ae8ffe7 JL |
1512 | case PLUS: |
1513 | case MINUS: | |
1514 | { | |
3c567fae JL |
1515 | rtx tmp1 = XEXP (x, 0); |
1516 | rtx tmp2 = XEXP (x, 1); | |
1517 | ||
f5143c46 | 1518 | /* This is a little bit tricky since we have to determine which of |
3c567fae JL |
1519 | the two operands represents the real base address. Otherwise this |
1520 | routine may return the index register instead of the base register. | |
1521 | ||
1522 | That may cause us to believe no aliasing was possible, when in | |
1523 | fact aliasing is possible. | |
1524 | ||
1525 | We use a few simple tests to guess the base register. Additional | |
1526 | tests can certainly be added. For example, if one of the operands | |
1527 | is a shift or multiply, then it must be the index register and the | |
1528 | other operand is the base register. */ | |
ca7fd9cd | 1529 | |
b949ea8b JW |
1530 | if (tmp1 == pic_offset_table_rtx && CONSTANT_P (tmp2)) |
1531 | return find_base_term (tmp2); | |
1532 | ||
3c567fae JL |
1533 | /* If either operand is known to be a pointer, then use it |
1534 | to determine the base term. */ | |
3502dc9c | 1535 | if (REG_P (tmp1) && REG_POINTER (tmp1)) |
7eba2d1f LM |
1536 | { |
1537 | rtx base = find_base_term (tmp1); | |
1538 | if (base) | |
1539 | return base; | |
1540 | } | |
3c567fae | 1541 | |
3502dc9c | 1542 | if (REG_P (tmp2) && REG_POINTER (tmp2)) |
7eba2d1f LM |
1543 | { |
1544 | rtx base = find_base_term (tmp2); | |
1545 | if (base) | |
1546 | return base; | |
1547 | } | |
3c567fae JL |
1548 | |
1549 | /* Neither operand was known to be a pointer. Go ahead and find the | |
1550 | base term for both operands. */ | |
1551 | tmp1 = find_base_term (tmp1); | |
1552 | tmp2 = find_base_term (tmp2); | |
1553 | ||
1554 | /* If either base term is named object or a special address | |
1555 | (like an argument or stack reference), then use it for the | |
1556 | base term. */ | |
d4b60170 | 1557 | if (tmp1 != 0 |
3c567fae JL |
1558 | && (GET_CODE (tmp1) == SYMBOL_REF |
1559 | || GET_CODE (tmp1) == LABEL_REF | |
1560 | || (GET_CODE (tmp1) == ADDRESS | |
1561 | && GET_MODE (tmp1) != VOIDmode))) | |
1562 | return tmp1; | |
1563 | ||
d4b60170 | 1564 | if (tmp2 != 0 |
3c567fae JL |
1565 | && (GET_CODE (tmp2) == SYMBOL_REF |
1566 | || GET_CODE (tmp2) == LABEL_REF | |
1567 | || (GET_CODE (tmp2) == ADDRESS | |
1568 | && GET_MODE (tmp2) != VOIDmode))) | |
1569 | return tmp2; | |
1570 | ||
1571 | /* We could not determine which of the two operands was the | |
1572 | base register and which was the index. So we can determine | |
1573 | nothing from the base alias check. */ | |
1574 | return 0; | |
9ae8ffe7 JL |
1575 | } |
1576 | ||
1577 | case AND: | |
481683e1 | 1578 | if (CONST_INT_P (XEXP (x, 1)) && INTVAL (XEXP (x, 1)) != 0) |
d288e53d | 1579 | return find_base_term (XEXP (x, 0)); |
9ae8ffe7 JL |
1580 | return 0; |
1581 | ||
1582 | case SYMBOL_REF: | |
1583 | case LABEL_REF: | |
1584 | return x; | |
1585 | ||
1586 | default: | |
1587 | return 0; | |
1588 | } | |
1589 | } | |
1590 | ||
1591 | /* Return 0 if the addresses X and Y are known to point to different | |
1592 | objects, 1 if they might be pointers to the same object. */ | |
1593 | ||
1594 | static int | |
4682ae04 AJ |
1595 | base_alias_check (rtx x, rtx y, enum machine_mode x_mode, |
1596 | enum machine_mode y_mode) | |
9ae8ffe7 JL |
1597 | { |
1598 | rtx x_base = find_base_term (x); | |
1599 | rtx y_base = find_base_term (y); | |
1600 | ||
1c72c7f6 JC |
1601 | /* If the address itself has no known base see if a known equivalent |
1602 | value has one. If either address still has no known base, nothing | |
1603 | is known about aliasing. */ | |
1604 | if (x_base == 0) | |
1605 | { | |
1606 | rtx x_c; | |
d4b60170 | 1607 | |
1c72c7f6 JC |
1608 | if (! flag_expensive_optimizations || (x_c = canon_rtx (x)) == x) |
1609 | return 1; | |
d4b60170 | 1610 | |
1c72c7f6 JC |
1611 | x_base = find_base_term (x_c); |
1612 | if (x_base == 0) | |
1613 | return 1; | |
1614 | } | |
9ae8ffe7 | 1615 | |
1c72c7f6 JC |
1616 | if (y_base == 0) |
1617 | { | |
1618 | rtx y_c; | |
1619 | if (! flag_expensive_optimizations || (y_c = canon_rtx (y)) == y) | |
1620 | return 1; | |
d4b60170 | 1621 | |
1c72c7f6 JC |
1622 | y_base = find_base_term (y_c); |
1623 | if (y_base == 0) | |
1624 | return 1; | |
1625 | } | |
1626 | ||
1627 | /* If the base addresses are equal nothing is known about aliasing. */ | |
1628 | if (rtx_equal_p (x_base, y_base)) | |
9ae8ffe7 JL |
1629 | return 1; |
1630 | ||
435da628 UB |
1631 | /* The base addresses are different expressions. If they are not accessed |
1632 | via AND, there is no conflict. We can bring knowledge of object | |
1633 | alignment into play here. For example, on alpha, "char a, b;" can | |
1634 | alias one another, though "char a; long b;" cannot. AND addesses may | |
1635 | implicitly alias surrounding objects; i.e. unaligned access in DImode | |
1636 | via AND address can alias all surrounding object types except those | |
1637 | with aligment 8 or higher. */ | |
1638 | if (GET_CODE (x) == AND && GET_CODE (y) == AND) | |
1639 | return 1; | |
1640 | if (GET_CODE (x) == AND | |
481683e1 | 1641 | && (!CONST_INT_P (XEXP (x, 1)) |
435da628 UB |
1642 | || (int) GET_MODE_UNIT_SIZE (y_mode) < -INTVAL (XEXP (x, 1)))) |
1643 | return 1; | |
1644 | if (GET_CODE (y) == AND | |
481683e1 | 1645 | && (!CONST_INT_P (XEXP (y, 1)) |
435da628 UB |
1646 | || (int) GET_MODE_UNIT_SIZE (x_mode) < -INTVAL (XEXP (y, 1)))) |
1647 | return 1; | |
1648 | ||
1649 | /* Differing symbols not accessed via AND never alias. */ | |
9ae8ffe7 | 1650 | if (GET_CODE (x_base) != ADDRESS && GET_CODE (y_base) != ADDRESS) |
435da628 | 1651 | return 0; |
9ae8ffe7 JL |
1652 | |
1653 | /* If one address is a stack reference there can be no alias: | |
1654 | stack references using different base registers do not alias, | |
1655 | a stack reference can not alias a parameter, and a stack reference | |
1656 | can not alias a global. */ | |
1657 | if ((GET_CODE (x_base) == ADDRESS && GET_MODE (x_base) == Pmode) | |
1658 | || (GET_CODE (y_base) == ADDRESS && GET_MODE (y_base) == Pmode)) | |
1659 | return 0; | |
1660 | ||
1661 | if (! flag_argument_noalias) | |
1662 | return 1; | |
1663 | ||
1664 | if (flag_argument_noalias > 1) | |
1665 | return 0; | |
1666 | ||
ec5c56db | 1667 | /* Weak noalias assertion (arguments are distinct, but may match globals). */ |
9ae8ffe7 JL |
1668 | return ! (GET_MODE (x_base) == VOIDmode && GET_MODE (y_base) == VOIDmode); |
1669 | } | |
1670 | ||
eab5c70a BS |
1671 | /* Convert the address X into something we can use. This is done by returning |
1672 | it unchanged unless it is a value; in the latter case we call cselib to get | |
1673 | a more useful rtx. */ | |
3bdf5ad1 | 1674 | |
a13d4ebf | 1675 | rtx |
4682ae04 | 1676 | get_addr (rtx x) |
eab5c70a BS |
1677 | { |
1678 | cselib_val *v; | |
1679 | struct elt_loc_list *l; | |
1680 | ||
1681 | if (GET_CODE (x) != VALUE) | |
1682 | return x; | |
1683 | v = CSELIB_VAL_PTR (x); | |
40e02b4a JH |
1684 | if (v) |
1685 | { | |
1686 | for (l = v->locs; l; l = l->next) | |
1687 | if (CONSTANT_P (l->loc)) | |
1688 | return l->loc; | |
1689 | for (l = v->locs; l; l = l->next) | |
3c0cb5de | 1690 | if (!REG_P (l->loc) && !MEM_P (l->loc)) |
40e02b4a JH |
1691 | return l->loc; |
1692 | if (v->locs) | |
1693 | return v->locs->loc; | |
1694 | } | |
eab5c70a BS |
1695 | return x; |
1696 | } | |
1697 | ||
39cec1ac MH |
1698 | /* Return the address of the (N_REFS + 1)th memory reference to ADDR |
1699 | where SIZE is the size in bytes of the memory reference. If ADDR | |
1700 | is not modified by the memory reference then ADDR is returned. */ | |
1701 | ||
04e2b4d3 | 1702 | static rtx |
4682ae04 | 1703 | addr_side_effect_eval (rtx addr, int size, int n_refs) |
39cec1ac MH |
1704 | { |
1705 | int offset = 0; | |
ca7fd9cd | 1706 | |
39cec1ac MH |
1707 | switch (GET_CODE (addr)) |
1708 | { | |
1709 | case PRE_INC: | |
1710 | offset = (n_refs + 1) * size; | |
1711 | break; | |
1712 | case PRE_DEC: | |
1713 | offset = -(n_refs + 1) * size; | |
1714 | break; | |
1715 | case POST_INC: | |
1716 | offset = n_refs * size; | |
1717 | break; | |
1718 | case POST_DEC: | |
1719 | offset = -n_refs * size; | |
1720 | break; | |
1721 | ||
1722 | default: | |
1723 | return addr; | |
1724 | } | |
ca7fd9cd | 1725 | |
39cec1ac | 1726 | if (offset) |
45183e03 | 1727 | addr = gen_rtx_PLUS (GET_MODE (addr), XEXP (addr, 0), |
c22cacf3 | 1728 | GEN_INT (offset)); |
39cec1ac MH |
1729 | else |
1730 | addr = XEXP (addr, 0); | |
45183e03 | 1731 | addr = canon_rtx (addr); |
39cec1ac MH |
1732 | |
1733 | return addr; | |
1734 | } | |
1735 | ||
9ae8ffe7 JL |
1736 | /* Return nonzero if X and Y (memory addresses) could reference the |
1737 | same location in memory. C is an offset accumulator. When | |
1738 | C is nonzero, we are testing aliases between X and Y + C. | |
1739 | XSIZE is the size in bytes of the X reference, | |
1740 | similarly YSIZE is the size in bytes for Y. | |
45183e03 | 1741 | Expect that canon_rtx has been already called for X and Y. |
9ae8ffe7 JL |
1742 | |
1743 | If XSIZE or YSIZE is zero, we do not know the amount of memory being | |
1744 | referenced (the reference was BLKmode), so make the most pessimistic | |
1745 | assumptions. | |
1746 | ||
c02f035f RH |
1747 | If XSIZE or YSIZE is negative, we may access memory outside the object |
1748 | being referenced as a side effect. This can happen when using AND to | |
1749 | align memory references, as is done on the Alpha. | |
1750 | ||
9ae8ffe7 | 1751 | Nice to notice that varying addresses cannot conflict with fp if no |
0211b6ab | 1752 | local variables had their addresses taken, but that's too hard now. */ |
9ae8ffe7 | 1753 | |
9ae8ffe7 | 1754 | static int |
4682ae04 | 1755 | memrefs_conflict_p (int xsize, rtx x, int ysize, rtx y, HOST_WIDE_INT c) |
9ae8ffe7 | 1756 | { |
eab5c70a BS |
1757 | if (GET_CODE (x) == VALUE) |
1758 | x = get_addr (x); | |
1759 | if (GET_CODE (y) == VALUE) | |
1760 | y = get_addr (y); | |
9ae8ffe7 JL |
1761 | if (GET_CODE (x) == HIGH) |
1762 | x = XEXP (x, 0); | |
1763 | else if (GET_CODE (x) == LO_SUM) | |
1764 | x = XEXP (x, 1); | |
1765 | else | |
45183e03 | 1766 | x = addr_side_effect_eval (x, xsize, 0); |
9ae8ffe7 JL |
1767 | if (GET_CODE (y) == HIGH) |
1768 | y = XEXP (y, 0); | |
1769 | else if (GET_CODE (y) == LO_SUM) | |
1770 | y = XEXP (y, 1); | |
1771 | else | |
45183e03 | 1772 | y = addr_side_effect_eval (y, ysize, 0); |
9ae8ffe7 JL |
1773 | |
1774 | if (rtx_equal_for_memref_p (x, y)) | |
1775 | { | |
c02f035f | 1776 | if (xsize <= 0 || ysize <= 0) |
9ae8ffe7 JL |
1777 | return 1; |
1778 | if (c >= 0 && xsize > c) | |
1779 | return 1; | |
1780 | if (c < 0 && ysize+c > 0) | |
1781 | return 1; | |
1782 | return 0; | |
1783 | } | |
1784 | ||
6e73e666 JC |
1785 | /* This code used to check for conflicts involving stack references and |
1786 | globals but the base address alias code now handles these cases. */ | |
9ae8ffe7 JL |
1787 | |
1788 | if (GET_CODE (x) == PLUS) | |
1789 | { | |
1790 | /* The fact that X is canonicalized means that this | |
1791 | PLUS rtx is canonicalized. */ | |
1792 | rtx x0 = XEXP (x, 0); | |
1793 | rtx x1 = XEXP (x, 1); | |
1794 | ||
1795 | if (GET_CODE (y) == PLUS) | |
1796 | { | |
1797 | /* The fact that Y is canonicalized means that this | |
1798 | PLUS rtx is canonicalized. */ | |
1799 | rtx y0 = XEXP (y, 0); | |
1800 | rtx y1 = XEXP (y, 1); | |
1801 | ||
1802 | if (rtx_equal_for_memref_p (x1, y1)) | |
1803 | return memrefs_conflict_p (xsize, x0, ysize, y0, c); | |
1804 | if (rtx_equal_for_memref_p (x0, y0)) | |
1805 | return memrefs_conflict_p (xsize, x1, ysize, y1, c); | |
481683e1 | 1806 | if (CONST_INT_P (x1)) |
63be02db | 1807 | { |
481683e1 | 1808 | if (CONST_INT_P (y1)) |
63be02db JM |
1809 | return memrefs_conflict_p (xsize, x0, ysize, y0, |
1810 | c - INTVAL (x1) + INTVAL (y1)); | |
1811 | else | |
1812 | return memrefs_conflict_p (xsize, x0, ysize, y, | |
1813 | c - INTVAL (x1)); | |
1814 | } | |
481683e1 | 1815 | else if (CONST_INT_P (y1)) |
9ae8ffe7 JL |
1816 | return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1)); |
1817 | ||
6e73e666 | 1818 | return 1; |
9ae8ffe7 | 1819 | } |
481683e1 | 1820 | else if (CONST_INT_P (x1)) |
9ae8ffe7 JL |
1821 | return memrefs_conflict_p (xsize, x0, ysize, y, c - INTVAL (x1)); |
1822 | } | |
1823 | else if (GET_CODE (y) == PLUS) | |
1824 | { | |
1825 | /* The fact that Y is canonicalized means that this | |
1826 | PLUS rtx is canonicalized. */ | |
1827 | rtx y0 = XEXP (y, 0); | |
1828 | rtx y1 = XEXP (y, 1); | |
1829 | ||
481683e1 | 1830 | if (CONST_INT_P (y1)) |
9ae8ffe7 JL |
1831 | return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1)); |
1832 | else | |
1833 | return 1; | |
1834 | } | |
1835 | ||
1836 | if (GET_CODE (x) == GET_CODE (y)) | |
1837 | switch (GET_CODE (x)) | |
1838 | { | |
1839 | case MULT: | |
1840 | { | |
1841 | /* Handle cases where we expect the second operands to be the | |
1842 | same, and check only whether the first operand would conflict | |
1843 | or not. */ | |
1844 | rtx x0, y0; | |
1845 | rtx x1 = canon_rtx (XEXP (x, 1)); | |
1846 | rtx y1 = canon_rtx (XEXP (y, 1)); | |
1847 | if (! rtx_equal_for_memref_p (x1, y1)) | |
1848 | return 1; | |
1849 | x0 = canon_rtx (XEXP (x, 0)); | |
1850 | y0 = canon_rtx (XEXP (y, 0)); | |
1851 | if (rtx_equal_for_memref_p (x0, y0)) | |
1852 | return (xsize == 0 || ysize == 0 | |
1853 | || (c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)); | |
1854 | ||
1855 | /* Can't properly adjust our sizes. */ | |
481683e1 | 1856 | if (!CONST_INT_P (x1)) |
9ae8ffe7 JL |
1857 | return 1; |
1858 | xsize /= INTVAL (x1); | |
1859 | ysize /= INTVAL (x1); | |
1860 | c /= INTVAL (x1); | |
1861 | return memrefs_conflict_p (xsize, x0, ysize, y0, c); | |
1862 | } | |
1d300e19 KG |
1863 | |
1864 | default: | |
1865 | break; | |
9ae8ffe7 JL |
1866 | } |
1867 | ||
1868 | /* Treat an access through an AND (e.g. a subword access on an Alpha) | |
ca7fd9cd | 1869 | as an access with indeterminate size. Assume that references |
56ee9281 RH |
1870 | besides AND are aligned, so if the size of the other reference is |
1871 | at least as large as the alignment, assume no other overlap. */ | |
481683e1 | 1872 | if (GET_CODE (x) == AND && CONST_INT_P (XEXP (x, 1))) |
56ee9281 | 1873 | { |
02e3377d | 1874 | if (GET_CODE (y) == AND || ysize < -INTVAL (XEXP (x, 1))) |
56ee9281 | 1875 | xsize = -1; |
45183e03 | 1876 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), ysize, y, c); |
56ee9281 | 1877 | } |
481683e1 | 1878 | if (GET_CODE (y) == AND && CONST_INT_P (XEXP (y, 1))) |
c02f035f | 1879 | { |
56ee9281 | 1880 | /* ??? If we are indexing far enough into the array/structure, we |
ca7fd9cd | 1881 | may yet be able to determine that we can not overlap. But we |
c02f035f | 1882 | also need to that we are far enough from the end not to overlap |
56ee9281 | 1883 | a following reference, so we do nothing with that for now. */ |
02e3377d | 1884 | if (GET_CODE (x) == AND || xsize < -INTVAL (XEXP (y, 1))) |
56ee9281 | 1885 | ysize = -1; |
45183e03 | 1886 | return memrefs_conflict_p (xsize, x, ysize, canon_rtx (XEXP (y, 0)), c); |
c02f035f | 1887 | } |
9ae8ffe7 JL |
1888 | |
1889 | if (CONSTANT_P (x)) | |
1890 | { | |
481683e1 | 1891 | if (CONST_INT_P (x) && CONST_INT_P (y)) |
9ae8ffe7 JL |
1892 | { |
1893 | c += (INTVAL (y) - INTVAL (x)); | |
c02f035f | 1894 | return (xsize <= 0 || ysize <= 0 |
9ae8ffe7 JL |
1895 | || (c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)); |
1896 | } | |
1897 | ||
1898 | if (GET_CODE (x) == CONST) | |
1899 | { | |
1900 | if (GET_CODE (y) == CONST) | |
1901 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), | |
1902 | ysize, canon_rtx (XEXP (y, 0)), c); | |
1903 | else | |
1904 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), | |
1905 | ysize, y, c); | |
1906 | } | |
1907 | if (GET_CODE (y) == CONST) | |
1908 | return memrefs_conflict_p (xsize, x, ysize, | |
1909 | canon_rtx (XEXP (y, 0)), c); | |
1910 | ||
1911 | if (CONSTANT_P (y)) | |
b949ea8b | 1912 | return (xsize <= 0 || ysize <= 0 |
c02f035f | 1913 | || (rtx_equal_for_memref_p (x, y) |
b949ea8b | 1914 | && ((c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)))); |
9ae8ffe7 JL |
1915 | |
1916 | return 1; | |
1917 | } | |
1918 | return 1; | |
1919 | } | |
1920 | ||
1921 | /* Functions to compute memory dependencies. | |
1922 | ||
1923 | Since we process the insns in execution order, we can build tables | |
1924 | to keep track of what registers are fixed (and not aliased), what registers | |
1925 | are varying in known ways, and what registers are varying in unknown | |
1926 | ways. | |
1927 | ||
1928 | If both memory references are volatile, then there must always be a | |
1929 | dependence between the two references, since their order can not be | |
1930 | changed. A volatile and non-volatile reference can be interchanged | |
ca7fd9cd | 1931 | though. |
9ae8ffe7 | 1932 | |
dc1618bc RK |
1933 | A MEM_IN_STRUCT reference at a non-AND varying address can never |
1934 | conflict with a non-MEM_IN_STRUCT reference at a fixed address. We | |
1935 | also must allow AND addresses, because they may generate accesses | |
1936 | outside the object being referenced. This is used to generate | |
1937 | aligned addresses from unaligned addresses, for instance, the alpha | |
1938 | storeqi_unaligned pattern. */ | |
9ae8ffe7 JL |
1939 | |
1940 | /* Read dependence: X is read after read in MEM takes place. There can | |
1941 | only be a dependence here if both reads are volatile. */ | |
1942 | ||
1943 | int | |
4f588890 | 1944 | read_dependence (const_rtx mem, const_rtx x) |
9ae8ffe7 JL |
1945 | { |
1946 | return MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem); | |
1947 | } | |
1948 | ||
c6df88cb MM |
1949 | /* Returns MEM1 if and only if MEM1 is a scalar at a fixed address and |
1950 | MEM2 is a reference to a structure at a varying address, or returns | |
1951 | MEM2 if vice versa. Otherwise, returns NULL_RTX. If a non-NULL | |
1952 | value is returned MEM1 and MEM2 can never alias. VARIES_P is used | |
1953 | to decide whether or not an address may vary; it should return | |
eab5c70a BS |
1954 | nonzero whenever variation is possible. |
1955 | MEM1_ADDR and MEM2_ADDR are the addresses of MEM1 and MEM2. */ | |
ca7fd9cd | 1956 | |
4f588890 KG |
1957 | static const_rtx |
1958 | fixed_scalar_and_varying_struct_p (const_rtx mem1, const_rtx mem2, rtx mem1_addr, | |
4682ae04 | 1959 | rtx mem2_addr, |
4f588890 | 1960 | bool (*varies_p) (const_rtx, bool)) |
ca7fd9cd | 1961 | { |
3e0abe15 GK |
1962 | if (! flag_strict_aliasing) |
1963 | return NULL_RTX; | |
1964 | ||
afa8f0fb AP |
1965 | if (MEM_ALIAS_SET (mem2) |
1966 | && MEM_SCALAR_P (mem1) && MEM_IN_STRUCT_P (mem2) | |
e38fe8e0 | 1967 | && !varies_p (mem1_addr, 1) && varies_p (mem2_addr, 1)) |
c6df88cb MM |
1968 | /* MEM1 is a scalar at a fixed address; MEM2 is a struct at a |
1969 | varying address. */ | |
1970 | return mem1; | |
1971 | ||
afa8f0fb AP |
1972 | if (MEM_ALIAS_SET (mem1) |
1973 | && MEM_IN_STRUCT_P (mem1) && MEM_SCALAR_P (mem2) | |
e38fe8e0 | 1974 | && varies_p (mem1_addr, 1) && !varies_p (mem2_addr, 1)) |
c6df88cb MM |
1975 | /* MEM2 is a scalar at a fixed address; MEM1 is a struct at a |
1976 | varying address. */ | |
1977 | return mem2; | |
1978 | ||
1979 | return NULL_RTX; | |
1980 | } | |
1981 | ||
1982 | /* Returns nonzero if something about the mode or address format MEM1 | |
1983 | indicates that it might well alias *anything*. */ | |
1984 | ||
2c72b78f | 1985 | static int |
4f588890 | 1986 | aliases_everything_p (const_rtx mem) |
c6df88cb | 1987 | { |
c6df88cb | 1988 | if (GET_CODE (XEXP (mem, 0)) == AND) |
35fd3193 | 1989 | /* If the address is an AND, it's very hard to know at what it is |
c6df88cb MM |
1990 | actually pointing. */ |
1991 | return 1; | |
ca7fd9cd | 1992 | |
c6df88cb MM |
1993 | return 0; |
1994 | } | |
1995 | ||
998d7deb RH |
1996 | /* Return true if we can determine that the fields referenced cannot |
1997 | overlap for any pair of objects. */ | |
1998 | ||
1999 | static bool | |
4f588890 | 2000 | nonoverlapping_component_refs_p (const_tree x, const_tree y) |
998d7deb | 2001 | { |
4f588890 | 2002 | const_tree fieldx, fieldy, typex, typey, orig_y; |
998d7deb | 2003 | |
4c7af939 AB |
2004 | if (!flag_strict_aliasing) |
2005 | return false; | |
2006 | ||
998d7deb RH |
2007 | do |
2008 | { | |
2009 | /* The comparison has to be done at a common type, since we don't | |
d6a7951f | 2010 | know how the inheritance hierarchy works. */ |
998d7deb RH |
2011 | orig_y = y; |
2012 | do | |
2013 | { | |
2014 | fieldx = TREE_OPERAND (x, 1); | |
c05a0766 | 2015 | typex = TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (fieldx)); |
998d7deb RH |
2016 | |
2017 | y = orig_y; | |
2018 | do | |
2019 | { | |
2020 | fieldy = TREE_OPERAND (y, 1); | |
c05a0766 | 2021 | typey = TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (fieldy)); |
998d7deb RH |
2022 | |
2023 | if (typex == typey) | |
2024 | goto found; | |
2025 | ||
2026 | y = TREE_OPERAND (y, 0); | |
2027 | } | |
2028 | while (y && TREE_CODE (y) == COMPONENT_REF); | |
2029 | ||
2030 | x = TREE_OPERAND (x, 0); | |
2031 | } | |
2032 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
998d7deb | 2033 | /* Never found a common type. */ |
c05a0766 | 2034 | return false; |
998d7deb RH |
2035 | |
2036 | found: | |
2037 | /* If we're left with accessing different fields of a structure, | |
2038 | then no overlap. */ | |
2039 | if (TREE_CODE (typex) == RECORD_TYPE | |
2040 | && fieldx != fieldy) | |
2041 | return true; | |
2042 | ||
2043 | /* The comparison on the current field failed. If we're accessing | |
2044 | a very nested structure, look at the next outer level. */ | |
2045 | x = TREE_OPERAND (x, 0); | |
2046 | y = TREE_OPERAND (y, 0); | |
2047 | } | |
2048 | while (x && y | |
2049 | && TREE_CODE (x) == COMPONENT_REF | |
2050 | && TREE_CODE (y) == COMPONENT_REF); | |
ca7fd9cd | 2051 | |
998d7deb RH |
2052 | return false; |
2053 | } | |
2054 | ||
2055 | /* Look at the bottom of the COMPONENT_REF list for a DECL, and return it. */ | |
2056 | ||
2057 | static tree | |
4682ae04 | 2058 | decl_for_component_ref (tree x) |
998d7deb RH |
2059 | { |
2060 | do | |
2061 | { | |
2062 | x = TREE_OPERAND (x, 0); | |
2063 | } | |
2064 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
2065 | ||
2066 | return x && DECL_P (x) ? x : NULL_TREE; | |
2067 | } | |
2068 | ||
2069 | /* Walk up the COMPONENT_REF list and adjust OFFSET to compensate for the | |
2070 | offset of the field reference. */ | |
2071 | ||
2072 | static rtx | |
4682ae04 | 2073 | adjust_offset_for_component_ref (tree x, rtx offset) |
998d7deb RH |
2074 | { |
2075 | HOST_WIDE_INT ioffset; | |
2076 | ||
2077 | if (! offset) | |
2078 | return NULL_RTX; | |
2079 | ||
2080 | ioffset = INTVAL (offset); | |
ca7fd9cd | 2081 | do |
998d7deb | 2082 | { |
44de5aeb | 2083 | tree offset = component_ref_field_offset (x); |
998d7deb RH |
2084 | tree field = TREE_OPERAND (x, 1); |
2085 | ||
44de5aeb | 2086 | if (! host_integerp (offset, 1)) |
998d7deb | 2087 | return NULL_RTX; |
44de5aeb | 2088 | ioffset += (tree_low_cst (offset, 1) |
998d7deb RH |
2089 | + (tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1) |
2090 | / BITS_PER_UNIT)); | |
2091 | ||
2092 | x = TREE_OPERAND (x, 0); | |
2093 | } | |
2094 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
2095 | ||
2096 | return GEN_INT (ioffset); | |
2097 | } | |
2098 | ||
95bd1dd7 | 2099 | /* Return nonzero if we can determine the exprs corresponding to memrefs |
a4311dfe RK |
2100 | X and Y and they do not overlap. */ |
2101 | ||
2e4e39f6 | 2102 | int |
4f588890 | 2103 | nonoverlapping_memrefs_p (const_rtx x, const_rtx y) |
a4311dfe | 2104 | { |
998d7deb | 2105 | tree exprx = MEM_EXPR (x), expry = MEM_EXPR (y); |
a4311dfe RK |
2106 | rtx rtlx, rtly; |
2107 | rtx basex, basey; | |
998d7deb | 2108 | rtx moffsetx, moffsety; |
a4311dfe RK |
2109 | HOST_WIDE_INT offsetx = 0, offsety = 0, sizex, sizey, tem; |
2110 | ||
998d7deb RH |
2111 | /* Unless both have exprs, we can't tell anything. */ |
2112 | if (exprx == 0 || expry == 0) | |
2113 | return 0; | |
c22cacf3 | 2114 | |
998d7deb RH |
2115 | /* If both are field references, we may be able to determine something. */ |
2116 | if (TREE_CODE (exprx) == COMPONENT_REF | |
2117 | && TREE_CODE (expry) == COMPONENT_REF | |
2118 | && nonoverlapping_component_refs_p (exprx, expry)) | |
2119 | return 1; | |
2120 | ||
c22cacf3 | 2121 | |
998d7deb RH |
2122 | /* If the field reference test failed, look at the DECLs involved. */ |
2123 | moffsetx = MEM_OFFSET (x); | |
2124 | if (TREE_CODE (exprx) == COMPONENT_REF) | |
2125 | { | |
ea900239 DB |
2126 | if (TREE_CODE (expry) == VAR_DECL |
2127 | && POINTER_TYPE_P (TREE_TYPE (expry))) | |
2128 | { | |
2129 | tree field = TREE_OPERAND (exprx, 1); | |
2130 | tree fieldcontext = DECL_FIELD_CONTEXT (field); | |
2131 | if (ipa_type_escape_field_does_not_clobber_p (fieldcontext, | |
2132 | TREE_TYPE (field))) | |
c22cacf3 | 2133 | return 1; |
ea900239 DB |
2134 | } |
2135 | { | |
2136 | tree t = decl_for_component_ref (exprx); | |
2137 | if (! t) | |
2138 | return 0; | |
2139 | moffsetx = adjust_offset_for_component_ref (exprx, moffsetx); | |
2140 | exprx = t; | |
2141 | } | |
998d7deb | 2142 | } |
1b096a0a | 2143 | else if (INDIRECT_REF_P (exprx)) |
c67a1cf6 RH |
2144 | { |
2145 | exprx = TREE_OPERAND (exprx, 0); | |
2146 | if (flag_argument_noalias < 2 | |
2147 | || TREE_CODE (exprx) != PARM_DECL) | |
2148 | return 0; | |
2149 | } | |
2150 | ||
998d7deb RH |
2151 | moffsety = MEM_OFFSET (y); |
2152 | if (TREE_CODE (expry) == COMPONENT_REF) | |
2153 | { | |
ea900239 DB |
2154 | if (TREE_CODE (exprx) == VAR_DECL |
2155 | && POINTER_TYPE_P (TREE_TYPE (exprx))) | |
2156 | { | |
2157 | tree field = TREE_OPERAND (expry, 1); | |
2158 | tree fieldcontext = DECL_FIELD_CONTEXT (field); | |
2159 | if (ipa_type_escape_field_does_not_clobber_p (fieldcontext, | |
2160 | TREE_TYPE (field))) | |
c22cacf3 | 2161 | return 1; |
ea900239 DB |
2162 | } |
2163 | { | |
2164 | tree t = decl_for_component_ref (expry); | |
2165 | if (! t) | |
2166 | return 0; | |
2167 | moffsety = adjust_offset_for_component_ref (expry, moffsety); | |
2168 | expry = t; | |
2169 | } | |
998d7deb | 2170 | } |
1b096a0a | 2171 | else if (INDIRECT_REF_P (expry)) |
c67a1cf6 RH |
2172 | { |
2173 | expry = TREE_OPERAND (expry, 0); | |
2174 | if (flag_argument_noalias < 2 | |
2175 | || TREE_CODE (expry) != PARM_DECL) | |
2176 | return 0; | |
2177 | } | |
998d7deb RH |
2178 | |
2179 | if (! DECL_P (exprx) || ! DECL_P (expry)) | |
a4311dfe RK |
2180 | return 0; |
2181 | ||
998d7deb RH |
2182 | rtlx = DECL_RTL (exprx); |
2183 | rtly = DECL_RTL (expry); | |
a4311dfe | 2184 | |
1edcd60b RK |
2185 | /* If either RTL is not a MEM, it must be a REG or CONCAT, meaning they |
2186 | can't overlap unless they are the same because we never reuse that part | |
2187 | of the stack frame used for locals for spilled pseudos. */ | |
3c0cb5de | 2188 | if ((!MEM_P (rtlx) || !MEM_P (rtly)) |
1edcd60b | 2189 | && ! rtx_equal_p (rtlx, rtly)) |
a4311dfe RK |
2190 | return 1; |
2191 | ||
2192 | /* Get the base and offsets of both decls. If either is a register, we | |
2193 | know both are and are the same, so use that as the base. The only | |
2194 | we can avoid overlap is if we can deduce that they are nonoverlapping | |
2195 | pieces of that decl, which is very rare. */ | |
3c0cb5de | 2196 | basex = MEM_P (rtlx) ? XEXP (rtlx, 0) : rtlx; |
481683e1 | 2197 | if (GET_CODE (basex) == PLUS && CONST_INT_P (XEXP (basex, 1))) |
a4311dfe RK |
2198 | offsetx = INTVAL (XEXP (basex, 1)), basex = XEXP (basex, 0); |
2199 | ||
3c0cb5de | 2200 | basey = MEM_P (rtly) ? XEXP (rtly, 0) : rtly; |
481683e1 | 2201 | if (GET_CODE (basey) == PLUS && CONST_INT_P (XEXP (basey, 1))) |
a4311dfe RK |
2202 | offsety = INTVAL (XEXP (basey, 1)), basey = XEXP (basey, 0); |
2203 | ||
d746694a | 2204 | /* If the bases are different, we know they do not overlap if both |
ca7fd9cd | 2205 | are constants or if one is a constant and the other a pointer into the |
d746694a RK |
2206 | stack frame. Otherwise a different base means we can't tell if they |
2207 | overlap or not. */ | |
2208 | if (! rtx_equal_p (basex, basey)) | |
ca7fd9cd KH |
2209 | return ((CONSTANT_P (basex) && CONSTANT_P (basey)) |
2210 | || (CONSTANT_P (basex) && REG_P (basey) | |
2211 | && REGNO_PTR_FRAME_P (REGNO (basey))) | |
2212 | || (CONSTANT_P (basey) && REG_P (basex) | |
2213 | && REGNO_PTR_FRAME_P (REGNO (basex)))); | |
a4311dfe | 2214 | |
3c0cb5de | 2215 | sizex = (!MEM_P (rtlx) ? (int) GET_MODE_SIZE (GET_MODE (rtlx)) |
a4311dfe RK |
2216 | : MEM_SIZE (rtlx) ? INTVAL (MEM_SIZE (rtlx)) |
2217 | : -1); | |
3c0cb5de | 2218 | sizey = (!MEM_P (rtly) ? (int) GET_MODE_SIZE (GET_MODE (rtly)) |
a4311dfe RK |
2219 | : MEM_SIZE (rtly) ? INTVAL (MEM_SIZE (rtly)) : |
2220 | -1); | |
2221 | ||
0af5bc3e RK |
2222 | /* If we have an offset for either memref, it can update the values computed |
2223 | above. */ | |
998d7deb RH |
2224 | if (moffsetx) |
2225 | offsetx += INTVAL (moffsetx), sizex -= INTVAL (moffsetx); | |
2226 | if (moffsety) | |
2227 | offsety += INTVAL (moffsety), sizey -= INTVAL (moffsety); | |
a4311dfe | 2228 | |
0af5bc3e | 2229 | /* If a memref has both a size and an offset, we can use the smaller size. |
efc981bb | 2230 | We can't do this if the offset isn't known because we must view this |
0af5bc3e | 2231 | memref as being anywhere inside the DECL's MEM. */ |
998d7deb | 2232 | if (MEM_SIZE (x) && moffsetx) |
a4311dfe | 2233 | sizex = INTVAL (MEM_SIZE (x)); |
998d7deb | 2234 | if (MEM_SIZE (y) && moffsety) |
a4311dfe RK |
2235 | sizey = INTVAL (MEM_SIZE (y)); |
2236 | ||
2237 | /* Put the values of the memref with the lower offset in X's values. */ | |
2238 | if (offsetx > offsety) | |
2239 | { | |
2240 | tem = offsetx, offsetx = offsety, offsety = tem; | |
2241 | tem = sizex, sizex = sizey, sizey = tem; | |
2242 | } | |
2243 | ||
2244 | /* If we don't know the size of the lower-offset value, we can't tell | |
2245 | if they conflict. Otherwise, we do the test. */ | |
a6f7c915 | 2246 | return sizex >= 0 && offsety >= offsetx + sizex; |
a4311dfe RK |
2247 | } |
2248 | ||
9ae8ffe7 JL |
2249 | /* True dependence: X is read after store in MEM takes place. */ |
2250 | ||
2251 | int | |
4f588890 KG |
2252 | true_dependence (const_rtx mem, enum machine_mode mem_mode, const_rtx x, |
2253 | bool (*varies) (const_rtx, bool)) | |
9ae8ffe7 | 2254 | { |
b3694847 | 2255 | rtx x_addr, mem_addr; |
49982682 | 2256 | rtx base; |
9ae8ffe7 JL |
2257 | |
2258 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) | |
2259 | return 1; | |
2260 | ||
c4484b8f | 2261 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
ac3768f6 | 2262 | This is used in epilogue deallocation functions, and in cselib. */ |
c4484b8f RH |
2263 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) |
2264 | return 1; | |
2265 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
2266 | return 1; | |
9cd9e512 RH |
2267 | if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER |
2268 | || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER) | |
2269 | return 1; | |
c4484b8f | 2270 | |
41472af8 MM |
2271 | if (DIFFERENT_ALIAS_SETS_P (x, mem)) |
2272 | return 0; | |
2273 | ||
389fdba0 RH |
2274 | /* Read-only memory is by definition never modified, and therefore can't |
2275 | conflict with anything. We don't expect to find read-only set on MEM, | |
41806d92 | 2276 | but stupid user tricks can produce them, so don't die. */ |
389fdba0 | 2277 | if (MEM_READONLY_P (x)) |
9ae8ffe7 JL |
2278 | return 0; |
2279 | ||
a4311dfe RK |
2280 | if (nonoverlapping_memrefs_p (mem, x)) |
2281 | return 0; | |
2282 | ||
56ee9281 RH |
2283 | if (mem_mode == VOIDmode) |
2284 | mem_mode = GET_MODE (mem); | |
2285 | ||
eab5c70a BS |
2286 | x_addr = get_addr (XEXP (x, 0)); |
2287 | mem_addr = get_addr (XEXP (mem, 0)); | |
2288 | ||
55efb413 JW |
2289 | base = find_base_term (x_addr); |
2290 | if (base && (GET_CODE (base) == LABEL_REF | |
2291 | || (GET_CODE (base) == SYMBOL_REF | |
2292 | && CONSTANT_POOL_ADDRESS_P (base)))) | |
2293 | return 0; | |
2294 | ||
eab5c70a | 2295 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), mem_mode)) |
1c72c7f6 JC |
2296 | return 0; |
2297 | ||
eab5c70a BS |
2298 | x_addr = canon_rtx (x_addr); |
2299 | mem_addr = canon_rtx (mem_addr); | |
6e73e666 | 2300 | |
0211b6ab JW |
2301 | if (! memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr, |
2302 | SIZE_FOR_MODE (x), x_addr, 0)) | |
2303 | return 0; | |
2304 | ||
c6df88cb | 2305 | if (aliases_everything_p (x)) |
0211b6ab JW |
2306 | return 1; |
2307 | ||
f5143c46 | 2308 | /* We cannot use aliases_everything_p to test MEM, since we must look |
c6df88cb MM |
2309 | at MEM_MODE, rather than GET_MODE (MEM). */ |
2310 | if (mem_mode == QImode || GET_CODE (mem_addr) == AND) | |
a13d4ebf AM |
2311 | return 1; |
2312 | ||
2313 | /* In true_dependence we also allow BLKmode to alias anything. Why | |
2314 | don't we do this in anti_dependence and output_dependence? */ | |
2315 | if (mem_mode == BLKmode || GET_MODE (x) == BLKmode) | |
2316 | return 1; | |
2317 | ||
55b34b5f RG |
2318 | if (fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, varies)) |
2319 | return 0; | |
2320 | ||
2321 | return rtx_refs_may_alias_p (x, mem, true); | |
a13d4ebf AM |
2322 | } |
2323 | ||
2324 | /* Canonical true dependence: X is read after store in MEM takes place. | |
ca7fd9cd KH |
2325 | Variant of true_dependence which assumes MEM has already been |
2326 | canonicalized (hence we no longer do that here). | |
2327 | The mem_addr argument has been added, since true_dependence computed | |
6216f94e JJ |
2328 | this value prior to canonicalizing. |
2329 | If x_addr is non-NULL, it is used in preference of XEXP (x, 0). */ | |
a13d4ebf AM |
2330 | |
2331 | int | |
4f588890 | 2332 | canon_true_dependence (const_rtx mem, enum machine_mode mem_mode, rtx mem_addr, |
6216f94e | 2333 | const_rtx x, rtx x_addr, bool (*varies) (const_rtx, bool)) |
a13d4ebf | 2334 | { |
a13d4ebf AM |
2335 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) |
2336 | return 1; | |
2337 | ||
0fe854a7 RH |
2338 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
2339 | This is used in epilogue deallocation functions. */ | |
2340 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) | |
2341 | return 1; | |
2342 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
2343 | return 1; | |
9cd9e512 RH |
2344 | if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER |
2345 | || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER) | |
2346 | return 1; | |
0fe854a7 | 2347 | |
a13d4ebf AM |
2348 | if (DIFFERENT_ALIAS_SETS_P (x, mem)) |
2349 | return 0; | |
2350 | ||
389fdba0 RH |
2351 | /* Read-only memory is by definition never modified, and therefore can't |
2352 | conflict with anything. We don't expect to find read-only set on MEM, | |
41806d92 | 2353 | but stupid user tricks can produce them, so don't die. */ |
389fdba0 | 2354 | if (MEM_READONLY_P (x)) |
a13d4ebf AM |
2355 | return 0; |
2356 | ||
a4311dfe RK |
2357 | if (nonoverlapping_memrefs_p (x, mem)) |
2358 | return 0; | |
2359 | ||
6216f94e JJ |
2360 | if (! x_addr) |
2361 | x_addr = get_addr (XEXP (x, 0)); | |
a13d4ebf AM |
2362 | |
2363 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), mem_mode)) | |
2364 | return 0; | |
2365 | ||
2366 | x_addr = canon_rtx (x_addr); | |
2367 | if (! memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr, | |
2368 | SIZE_FOR_MODE (x), x_addr, 0)) | |
2369 | return 0; | |
2370 | ||
2371 | if (aliases_everything_p (x)) | |
2372 | return 1; | |
2373 | ||
f5143c46 | 2374 | /* We cannot use aliases_everything_p to test MEM, since we must look |
a13d4ebf AM |
2375 | at MEM_MODE, rather than GET_MODE (MEM). */ |
2376 | if (mem_mode == QImode || GET_CODE (mem_addr) == AND) | |
c6df88cb | 2377 | return 1; |
0211b6ab | 2378 | |
c6df88cb MM |
2379 | /* In true_dependence we also allow BLKmode to alias anything. Why |
2380 | don't we do this in anti_dependence and output_dependence? */ | |
2381 | if (mem_mode == BLKmode || GET_MODE (x) == BLKmode) | |
2382 | return 1; | |
0211b6ab | 2383 | |
55b34b5f RG |
2384 | if (fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, varies)) |
2385 | return 0; | |
2386 | ||
2387 | return rtx_refs_may_alias_p (x, mem, true); | |
9ae8ffe7 JL |
2388 | } |
2389 | ||
da7d8304 | 2390 | /* Returns nonzero if a write to X might alias a previous read from |
389fdba0 | 2391 | (or, if WRITEP is nonzero, a write to) MEM. */ |
9ae8ffe7 | 2392 | |
2c72b78f | 2393 | static int |
4f588890 | 2394 | write_dependence_p (const_rtx mem, const_rtx x, int writep) |
9ae8ffe7 | 2395 | { |
6e73e666 | 2396 | rtx x_addr, mem_addr; |
4f588890 | 2397 | const_rtx fixed_scalar; |
49982682 | 2398 | rtx base; |
6e73e666 | 2399 | |
9ae8ffe7 JL |
2400 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) |
2401 | return 1; | |
2402 | ||
c4484b8f RH |
2403 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
2404 | This is used in epilogue deallocation functions. */ | |
2405 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) | |
2406 | return 1; | |
2407 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
2408 | return 1; | |
9cd9e512 RH |
2409 | if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER |
2410 | || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER) | |
2411 | return 1; | |
c4484b8f | 2412 | |
389fdba0 RH |
2413 | /* A read from read-only memory can't conflict with read-write memory. */ |
2414 | if (!writep && MEM_READONLY_P (mem)) | |
2415 | return 0; | |
55efb413 | 2416 | |
a4311dfe RK |
2417 | if (nonoverlapping_memrefs_p (x, mem)) |
2418 | return 0; | |
2419 | ||
55efb413 JW |
2420 | x_addr = get_addr (XEXP (x, 0)); |
2421 | mem_addr = get_addr (XEXP (mem, 0)); | |
2422 | ||
49982682 JW |
2423 | if (! writep) |
2424 | { | |
55efb413 | 2425 | base = find_base_term (mem_addr); |
49982682 JW |
2426 | if (base && (GET_CODE (base) == LABEL_REF |
2427 | || (GET_CODE (base) == SYMBOL_REF | |
2428 | && CONSTANT_POOL_ADDRESS_P (base)))) | |
2429 | return 0; | |
2430 | } | |
2431 | ||
eab5c70a BS |
2432 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), |
2433 | GET_MODE (mem))) | |
41472af8 MM |
2434 | return 0; |
2435 | ||
eab5c70a BS |
2436 | x_addr = canon_rtx (x_addr); |
2437 | mem_addr = canon_rtx (mem_addr); | |
6e73e666 | 2438 | |
c6df88cb MM |
2439 | if (!memrefs_conflict_p (SIZE_FOR_MODE (mem), mem_addr, |
2440 | SIZE_FOR_MODE (x), x_addr, 0)) | |
2441 | return 0; | |
2442 | ||
ca7fd9cd | 2443 | fixed_scalar |
eab5c70a BS |
2444 | = fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, |
2445 | rtx_addr_varies_p); | |
2446 | ||
55b34b5f RG |
2447 | if ((fixed_scalar == mem && !aliases_everything_p (x)) |
2448 | || (fixed_scalar == x && !aliases_everything_p (mem))) | |
2449 | return 0; | |
2450 | ||
2451 | return rtx_refs_may_alias_p (x, mem, false); | |
c6df88cb MM |
2452 | } |
2453 | ||
2454 | /* Anti dependence: X is written after read in MEM takes place. */ | |
2455 | ||
2456 | int | |
4f588890 | 2457 | anti_dependence (const_rtx mem, const_rtx x) |
c6df88cb | 2458 | { |
389fdba0 | 2459 | return write_dependence_p (mem, x, /*writep=*/0); |
9ae8ffe7 JL |
2460 | } |
2461 | ||
2462 | /* Output dependence: X is written after store in MEM takes place. */ | |
2463 | ||
2464 | int | |
4f588890 | 2465 | output_dependence (const_rtx mem, const_rtx x) |
9ae8ffe7 | 2466 | { |
389fdba0 | 2467 | return write_dependence_p (mem, x, /*writep=*/1); |
9ae8ffe7 | 2468 | } |
c14b9960 | 2469 | \f |
6e73e666 | 2470 | |
6e73e666 | 2471 | void |
b5deb7b6 | 2472 | init_alias_target (void) |
6e73e666 | 2473 | { |
b3694847 | 2474 | int i; |
6e73e666 | 2475 | |
b5deb7b6 SL |
2476 | memset (static_reg_base_value, 0, sizeof static_reg_base_value); |
2477 | ||
6e73e666 JC |
2478 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) |
2479 | /* Check whether this register can hold an incoming pointer | |
2480 | argument. FUNCTION_ARG_REGNO_P tests outgoing register | |
ec5c56db | 2481 | numbers, so translate if necessary due to register windows. */ |
6e73e666 JC |
2482 | if (FUNCTION_ARG_REGNO_P (OUTGOING_REGNO (i)) |
2483 | && HARD_REGNO_MODE_OK (i, Pmode)) | |
bf1660a6 JL |
2484 | static_reg_base_value[i] |
2485 | = gen_rtx_ADDRESS (VOIDmode, gen_rtx_REG (Pmode, i)); | |
2486 | ||
bf1660a6 JL |
2487 | static_reg_base_value[STACK_POINTER_REGNUM] |
2488 | = gen_rtx_ADDRESS (Pmode, stack_pointer_rtx); | |
2489 | static_reg_base_value[ARG_POINTER_REGNUM] | |
2490 | = gen_rtx_ADDRESS (Pmode, arg_pointer_rtx); | |
2491 | static_reg_base_value[FRAME_POINTER_REGNUM] | |
2492 | = gen_rtx_ADDRESS (Pmode, frame_pointer_rtx); | |
2493 | #if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM | |
2494 | static_reg_base_value[HARD_FRAME_POINTER_REGNUM] | |
2495 | = gen_rtx_ADDRESS (Pmode, hard_frame_pointer_rtx); | |
2496 | #endif | |
2497 | } | |
2498 | ||
7b52eede JH |
2499 | /* Set MEMORY_MODIFIED when X modifies DATA (that is assumed |
2500 | to be memory reference. */ | |
2501 | static bool memory_modified; | |
2502 | static void | |
aa317c97 | 2503 | memory_modified_1 (rtx x, const_rtx pat ATTRIBUTE_UNUSED, void *data) |
7b52eede | 2504 | { |
3c0cb5de | 2505 | if (MEM_P (x)) |
7b52eede | 2506 | { |
9678086d | 2507 | if (anti_dependence (x, (const_rtx)data) || output_dependence (x, (const_rtx)data)) |
7b52eede JH |
2508 | memory_modified = true; |
2509 | } | |
2510 | } | |
2511 | ||
2512 | ||
2513 | /* Return true when INSN possibly modify memory contents of MEM | |
454ff5cb | 2514 | (i.e. address can be modified). */ |
7b52eede | 2515 | bool |
9678086d | 2516 | memory_modified_in_insn_p (const_rtx mem, const_rtx insn) |
7b52eede JH |
2517 | { |
2518 | if (!INSN_P (insn)) | |
2519 | return false; | |
2520 | memory_modified = false; | |
aa317c97 | 2521 | note_stores (PATTERN (insn), memory_modified_1, CONST_CAST_RTX(mem)); |
7b52eede JH |
2522 | return memory_modified; |
2523 | } | |
2524 | ||
c13e8210 MM |
2525 | /* Initialize the aliasing machinery. Initialize the REG_KNOWN_VALUE |
2526 | array. */ | |
2527 | ||
9ae8ffe7 | 2528 | void |
4682ae04 | 2529 | init_alias_analysis (void) |
9ae8ffe7 | 2530 | { |
c582d54a | 2531 | unsigned int maxreg = max_reg_num (); |
ea64ef27 | 2532 | int changed, pass; |
b3694847 SS |
2533 | int i; |
2534 | unsigned int ui; | |
2535 | rtx insn; | |
9ae8ffe7 | 2536 | |
0d446150 JH |
2537 | timevar_push (TV_ALIAS_ANALYSIS); |
2538 | ||
bb1acb3e | 2539 | reg_known_value_size = maxreg - FIRST_PSEUDO_REGISTER; |
f883e0a7 KG |
2540 | reg_known_value = GGC_CNEWVEC (rtx, reg_known_value_size); |
2541 | reg_known_equiv_p = XCNEWVEC (bool, reg_known_value_size); | |
9ae8ffe7 | 2542 | |
08c79682 | 2543 | /* If we have memory allocated from the previous run, use it. */ |
c582d54a | 2544 | if (old_reg_base_value) |
08c79682 KH |
2545 | reg_base_value = old_reg_base_value; |
2546 | ||
2547 | if (reg_base_value) | |
2548 | VEC_truncate (rtx, reg_base_value, 0); | |
2549 | ||
a590ac65 | 2550 | VEC_safe_grow_cleared (rtx, gc, reg_base_value, maxreg); |
ac606739 | 2551 | |
5ed6ace5 MD |
2552 | new_reg_base_value = XNEWVEC (rtx, maxreg); |
2553 | reg_seen = XNEWVEC (char, maxreg); | |
ec907dd8 JL |
2554 | |
2555 | /* The basic idea is that each pass through this loop will use the | |
2556 | "constant" information from the previous pass to propagate alias | |
2557 | information through another level of assignments. | |
2558 | ||
2559 | This could get expensive if the assignment chains are long. Maybe | |
2560 | we should throttle the number of iterations, possibly based on | |
6e73e666 | 2561 | the optimization level or flag_expensive_optimizations. |
ec907dd8 JL |
2562 | |
2563 | We could propagate more information in the first pass by making use | |
6fb5fa3c | 2564 | of DF_REG_DEF_COUNT to determine immediately that the alias information |
ea64ef27 JL |
2565 | for a pseudo is "constant". |
2566 | ||
2567 | A program with an uninitialized variable can cause an infinite loop | |
2568 | here. Instead of doing a full dataflow analysis to detect such problems | |
2569 | we just cap the number of iterations for the loop. | |
2570 | ||
2571 | The state of the arrays for the set chain in question does not matter | |
2572 | since the program has undefined behavior. */ | |
6e73e666 | 2573 | |
ea64ef27 | 2574 | pass = 0; |
6e73e666 | 2575 | do |
ec907dd8 JL |
2576 | { |
2577 | /* Assume nothing will change this iteration of the loop. */ | |
2578 | changed = 0; | |
2579 | ||
ec907dd8 JL |
2580 | /* We want to assign the same IDs each iteration of this loop, so |
2581 | start counting from zero each iteration of the loop. */ | |
2582 | unique_id = 0; | |
2583 | ||
f5143c46 | 2584 | /* We're at the start of the function each iteration through the |
ec907dd8 | 2585 | loop, so we're copying arguments. */ |
83bbd9b6 | 2586 | copying_arguments = true; |
9ae8ffe7 | 2587 | |
6e73e666 | 2588 | /* Wipe the potential alias information clean for this pass. */ |
c582d54a | 2589 | memset (new_reg_base_value, 0, maxreg * sizeof (rtx)); |
8072f69c | 2590 | |
6e73e666 | 2591 | /* Wipe the reg_seen array clean. */ |
c582d54a | 2592 | memset (reg_seen, 0, maxreg); |
9ae8ffe7 | 2593 | |
6e73e666 JC |
2594 | /* Mark all hard registers which may contain an address. |
2595 | The stack, frame and argument pointers may contain an address. | |
2596 | An argument register which can hold a Pmode value may contain | |
2597 | an address even if it is not in BASE_REGS. | |
8072f69c | 2598 | |
6e73e666 JC |
2599 | The address expression is VOIDmode for an argument and |
2600 | Pmode for other registers. */ | |
2601 | ||
7f243674 JL |
2602 | memcpy (new_reg_base_value, static_reg_base_value, |
2603 | FIRST_PSEUDO_REGISTER * sizeof (rtx)); | |
6e73e666 | 2604 | |
ec907dd8 JL |
2605 | /* Walk the insns adding values to the new_reg_base_value array. */ |
2606 | for (insn = get_insns (); insn; insn = NEXT_INSN (insn)) | |
9ae8ffe7 | 2607 | { |
2c3c49de | 2608 | if (INSN_P (insn)) |
ec907dd8 | 2609 | { |
6e73e666 | 2610 | rtx note, set; |
efc9bd41 RK |
2611 | |
2612 | #if defined (HAVE_prologue) || defined (HAVE_epilogue) | |
f5143c46 | 2613 | /* The prologue/epilogue insns are not threaded onto the |
657959ca JL |
2614 | insn chain until after reload has completed. Thus, |
2615 | there is no sense wasting time checking if INSN is in | |
2616 | the prologue/epilogue until after reload has completed. */ | |
2617 | if (reload_completed | |
2618 | && prologue_epilogue_contains (insn)) | |
efc9bd41 RK |
2619 | continue; |
2620 | #endif | |
2621 | ||
ec907dd8 | 2622 | /* If this insn has a noalias note, process it, Otherwise, |
c22cacf3 MS |
2623 | scan for sets. A simple set will have no side effects |
2624 | which could change the base value of any other register. */ | |
6e73e666 | 2625 | |
ec907dd8 | 2626 | if (GET_CODE (PATTERN (insn)) == SET |
efc9bd41 RK |
2627 | && REG_NOTES (insn) != 0 |
2628 | && find_reg_note (insn, REG_NOALIAS, NULL_RTX)) | |
84832317 | 2629 | record_set (SET_DEST (PATTERN (insn)), NULL_RTX, NULL); |
ec907dd8 | 2630 | else |
84832317 | 2631 | note_stores (PATTERN (insn), record_set, NULL); |
6e73e666 JC |
2632 | |
2633 | set = single_set (insn); | |
2634 | ||
2635 | if (set != 0 | |
f8cfc6aa | 2636 | && REG_P (SET_DEST (set)) |
fb6754f0 | 2637 | && REGNO (SET_DEST (set)) >= FIRST_PSEUDO_REGISTER) |
6e73e666 | 2638 | { |
fb6754f0 | 2639 | unsigned int regno = REGNO (SET_DEST (set)); |
713f41f9 | 2640 | rtx src = SET_SRC (set); |
bb1acb3e | 2641 | rtx t; |
713f41f9 | 2642 | |
a31830a7 SB |
2643 | note = find_reg_equal_equiv_note (insn); |
2644 | if (note && REG_NOTE_KIND (note) == REG_EQUAL | |
6fb5fa3c | 2645 | && DF_REG_DEF_COUNT (regno) != 1) |
a31830a7 SB |
2646 | note = NULL_RTX; |
2647 | ||
2648 | if (note != NULL_RTX | |
713f41f9 | 2649 | && GET_CODE (XEXP (note, 0)) != EXPR_LIST |
bb2cf916 | 2650 | && ! rtx_varies_p (XEXP (note, 0), 1) |
bb1acb3e RH |
2651 | && ! reg_overlap_mentioned_p (SET_DEST (set), |
2652 | XEXP (note, 0))) | |
713f41f9 | 2653 | { |
bb1acb3e RH |
2654 | set_reg_known_value (regno, XEXP (note, 0)); |
2655 | set_reg_known_equiv_p (regno, | |
2656 | REG_NOTE_KIND (note) == REG_EQUIV); | |
713f41f9 | 2657 | } |
6fb5fa3c | 2658 | else if (DF_REG_DEF_COUNT (regno) == 1 |
713f41f9 | 2659 | && GET_CODE (src) == PLUS |
f8cfc6aa | 2660 | && REG_P (XEXP (src, 0)) |
bb1acb3e | 2661 | && (t = get_reg_known_value (REGNO (XEXP (src, 0)))) |
481683e1 | 2662 | && CONST_INT_P (XEXP (src, 1))) |
713f41f9 | 2663 | { |
bb1acb3e RH |
2664 | t = plus_constant (t, INTVAL (XEXP (src, 1))); |
2665 | set_reg_known_value (regno, t); | |
2666 | set_reg_known_equiv_p (regno, 0); | |
713f41f9 | 2667 | } |
6fb5fa3c | 2668 | else if (DF_REG_DEF_COUNT (regno) == 1 |
713f41f9 BS |
2669 | && ! rtx_varies_p (src, 1)) |
2670 | { | |
bb1acb3e RH |
2671 | set_reg_known_value (regno, src); |
2672 | set_reg_known_equiv_p (regno, 0); | |
713f41f9 | 2673 | } |
6e73e666 | 2674 | } |
ec907dd8 | 2675 | } |
4b4bf941 | 2676 | else if (NOTE_P (insn) |
a38e7aa5 | 2677 | && NOTE_KIND (insn) == NOTE_INSN_FUNCTION_BEG) |
83bbd9b6 | 2678 | copying_arguments = false; |
6e73e666 | 2679 | } |
ec907dd8 | 2680 | |
6e73e666 | 2681 | /* Now propagate values from new_reg_base_value to reg_base_value. */ |
62e5bf5d | 2682 | gcc_assert (maxreg == (unsigned int) max_reg_num ()); |
c22cacf3 | 2683 | |
c582d54a | 2684 | for (ui = 0; ui < maxreg; ui++) |
6e73e666 | 2685 | { |
e51712db | 2686 | if (new_reg_base_value[ui] |
08c79682 | 2687 | && new_reg_base_value[ui] != VEC_index (rtx, reg_base_value, ui) |
c582d54a | 2688 | && ! rtx_equal_p (new_reg_base_value[ui], |
08c79682 | 2689 | VEC_index (rtx, reg_base_value, ui))) |
ec907dd8 | 2690 | { |
08c79682 | 2691 | VEC_replace (rtx, reg_base_value, ui, new_reg_base_value[ui]); |
6e73e666 | 2692 | changed = 1; |
ec907dd8 | 2693 | } |
9ae8ffe7 | 2694 | } |
9ae8ffe7 | 2695 | } |
6e73e666 | 2696 | while (changed && ++pass < MAX_ALIAS_LOOP_PASSES); |
9ae8ffe7 JL |
2697 | |
2698 | /* Fill in the remaining entries. */ | |
bb1acb3e | 2699 | for (i = 0; i < (int)reg_known_value_size; i++) |
9ae8ffe7 | 2700 | if (reg_known_value[i] == 0) |
bb1acb3e | 2701 | reg_known_value[i] = regno_reg_rtx[i + FIRST_PSEUDO_REGISTER]; |
9ae8ffe7 | 2702 | |
e05e2395 MM |
2703 | /* Clean up. */ |
2704 | free (new_reg_base_value); | |
ec907dd8 | 2705 | new_reg_base_value = 0; |
e05e2395 | 2706 | free (reg_seen); |
9ae8ffe7 | 2707 | reg_seen = 0; |
0d446150 | 2708 | timevar_pop (TV_ALIAS_ANALYSIS); |
9ae8ffe7 JL |
2709 | } |
2710 | ||
2711 | void | |
4682ae04 | 2712 | end_alias_analysis (void) |
9ae8ffe7 | 2713 | { |
c582d54a | 2714 | old_reg_base_value = reg_base_value; |
bb1acb3e | 2715 | ggc_free (reg_known_value); |
9ae8ffe7 | 2716 | reg_known_value = 0; |
ac606739 | 2717 | reg_known_value_size = 0; |
bb1acb3e | 2718 | free (reg_known_equiv_p); |
e05e2395 | 2719 | reg_known_equiv_p = 0; |
9ae8ffe7 | 2720 | } |
e2500fed GK |
2721 | |
2722 | #include "gt-alias.h" |