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9ae8ffe7 | 1 | /* Alias analysis for GNU C |
d1e082c2 | 2 | Copyright (C) 1997-2013 Free Software Foundation, Inc. |
9ae8ffe7 JL |
3 | Contributed by John Carr (jfc@mit.edu). |
4 | ||
1322177d | 5 | This file is part of GCC. |
9ae8ffe7 | 6 | |
1322177d LB |
7 | GCC is free software; you can redistribute it and/or modify it under |
8 | the terms of the GNU General Public License as published by the Free | |
9dcd6f09 | 9 | Software Foundation; either version 3, or (at your option) any later |
1322177d | 10 | version. |
9ae8ffe7 | 11 | |
1322177d LB |
12 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY |
13 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
14 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
15 | for more details. | |
9ae8ffe7 JL |
16 | |
17 | You should have received a copy of the GNU General Public License | |
9dcd6f09 NC |
18 | along with GCC; see the file COPYING3. If not see |
19 | <http://www.gnu.org/licenses/>. */ | |
9ae8ffe7 JL |
20 | |
21 | #include "config.h" | |
670ee920 | 22 | #include "system.h" |
4977bab6 ZW |
23 | #include "coretypes.h" |
24 | #include "tm.h" | |
9ae8ffe7 | 25 | #include "rtl.h" |
7790df19 | 26 | #include "tree.h" |
6baf1cc8 | 27 | #include "tm_p.h" |
49ad7cfa | 28 | #include "function.h" |
78528714 JQ |
29 | #include "alias.h" |
30 | #include "emit-rtl.h" | |
9ae8ffe7 JL |
31 | #include "regs.h" |
32 | #include "hard-reg-set.h" | |
e004f2f7 | 33 | #include "basic-block.h" |
9ae8ffe7 | 34 | #include "flags.h" |
718f9c0f | 35 | #include "diagnostic-core.h" |
eab5c70a | 36 | #include "cselib.h" |
3932261a | 37 | #include "splay-tree.h" |
ac606739 | 38 | #include "ggc.h" |
d23c55c2 | 39 | #include "langhooks.h" |
0d446150 | 40 | #include "timevar.h" |
7ee2468b | 41 | #include "dumpfile.h" |
ab780373 | 42 | #include "target.h" |
b255a036 | 43 | #include "cgraph.h" |
6fb5fa3c | 44 | #include "df.h" |
55b34b5f RG |
45 | #include "tree-ssa-alias.h" |
46 | #include "pointer-set.h" | |
47 | #include "tree-flow.h" | |
ea900239 DB |
48 | |
49 | /* The aliasing API provided here solves related but different problems: | |
50 | ||
c22cacf3 | 51 | Say there exists (in c) |
ea900239 DB |
52 | |
53 | struct X { | |
54 | struct Y y1; | |
55 | struct Z z2; | |
56 | } x1, *px1, *px2; | |
57 | ||
58 | struct Y y2, *py; | |
59 | struct Z z2, *pz; | |
60 | ||
61 | ||
308a3fe2 | 62 | py = &x1.y1; |
ea900239 DB |
63 | px2 = &x1; |
64 | ||
65 | Consider the four questions: | |
66 | ||
67 | Can a store to x1 interfere with px2->y1? | |
68 | Can a store to x1 interfere with px2->z2? | |
ea900239 DB |
69 | Can a store to x1 change the value pointed to by with py? |
70 | Can a store to x1 change the value pointed to by with pz? | |
71 | ||
72 | The answer to these questions can be yes, yes, yes, and maybe. | |
73 | ||
74 | The first two questions can be answered with a simple examination | |
75 | of the type system. If structure X contains a field of type Y then | |
073a8998 | 76 | a store through a pointer to an X can overwrite any field that is |
ea900239 DB |
77 | contained (recursively) in an X (unless we know that px1 != px2). |
78 | ||
308a3fe2 DS |
79 | The last two questions can be solved in the same way as the first |
80 | two questions but this is too conservative. The observation is | |
81 | that in some cases we can know which (if any) fields are addressed | |
82 | and if those addresses are used in bad ways. This analysis may be | |
83 | language specific. In C, arbitrary operations may be applied to | |
84 | pointers. However, there is some indication that this may be too | |
85 | conservative for some C++ types. | |
ea900239 DB |
86 | |
87 | The pass ipa-type-escape does this analysis for the types whose | |
c22cacf3 | 88 | instances do not escape across the compilation boundary. |
ea900239 DB |
89 | |
90 | Historically in GCC, these two problems were combined and a single | |
308a3fe2 | 91 | data structure that was used to represent the solution to these |
ea900239 | 92 | problems. We now have two similar but different data structures, |
308a3fe2 DS |
93 | The data structure to solve the last two questions is similar to |
94 | the first, but does not contain the fields whose address are never | |
95 | taken. For types that do escape the compilation unit, the data | |
96 | structures will have identical information. | |
ea900239 | 97 | */ |
3932261a MM |
98 | |
99 | /* The alias sets assigned to MEMs assist the back-end in determining | |
100 | which MEMs can alias which other MEMs. In general, two MEMs in | |
ac3d9668 RK |
101 | different alias sets cannot alias each other, with one important |
102 | exception. Consider something like: | |
3932261a | 103 | |
01d28c3f | 104 | struct S { int i; double d; }; |
3932261a MM |
105 | |
106 | a store to an `S' can alias something of either type `int' or type | |
107 | `double'. (However, a store to an `int' cannot alias a `double' | |
108 | and vice versa.) We indicate this via a tree structure that looks | |
109 | like: | |
c22cacf3 MS |
110 | struct S |
111 | / \ | |
3932261a | 112 | / \ |
c22cacf3 MS |
113 | |/_ _\| |
114 | int double | |
3932261a | 115 | |
ac3d9668 RK |
116 | (The arrows are directed and point downwards.) |
117 | In this situation we say the alias set for `struct S' is the | |
118 | `superset' and that those for `int' and `double' are `subsets'. | |
119 | ||
3bdf5ad1 RK |
120 | To see whether two alias sets can point to the same memory, we must |
121 | see if either alias set is a subset of the other. We need not trace | |
95bd1dd7 | 122 | past immediate descendants, however, since we propagate all |
3bdf5ad1 | 123 | grandchildren up one level. |
3932261a MM |
124 | |
125 | Alias set zero is implicitly a superset of all other alias sets. | |
126 | However, this is no actual entry for alias set zero. It is an | |
127 | error to attempt to explicitly construct a subset of zero. */ | |
128 | ||
7e5487a2 | 129 | struct GTY(()) alias_set_entry_d { |
3932261a | 130 | /* The alias set number, as stored in MEM_ALIAS_SET. */ |
4862826d | 131 | alias_set_type alias_set; |
3932261a | 132 | |
4c067742 RG |
133 | /* Nonzero if would have a child of zero: this effectively makes this |
134 | alias set the same as alias set zero. */ | |
135 | int has_zero_child; | |
136 | ||
3932261a | 137 | /* The children of the alias set. These are not just the immediate |
95bd1dd7 | 138 | children, but, in fact, all descendants. So, if we have: |
3932261a | 139 | |
ca7fd9cd | 140 | struct T { struct S s; float f; } |
3932261a MM |
141 | |
142 | continuing our example above, the children here will be all of | |
143 | `int', `double', `float', and `struct S'. */ | |
b604074c | 144 | splay_tree GTY((param1_is (int), param2_is (int))) children; |
b604074c | 145 | }; |
7e5487a2 | 146 | typedef struct alias_set_entry_d *alias_set_entry; |
9ae8ffe7 | 147 | |
ed7a4b4b | 148 | static int rtx_equal_for_memref_p (const_rtx, const_rtx); |
4682ae04 | 149 | static int memrefs_conflict_p (int, rtx, int, rtx, HOST_WIDE_INT); |
7bc980e1 | 150 | static void record_set (rtx, const_rtx, void *); |
4682ae04 AJ |
151 | static int base_alias_check (rtx, rtx, enum machine_mode, |
152 | enum machine_mode); | |
153 | static rtx find_base_value (rtx); | |
4f588890 | 154 | static int mems_in_disjoint_alias_sets_p (const_rtx, const_rtx); |
4682ae04 | 155 | static int insert_subset_children (splay_tree_node, void*); |
4862826d | 156 | static alias_set_entry get_alias_set_entry (alias_set_type); |
175a7536 | 157 | static bool nonoverlapping_component_refs_p (const_rtx, const_rtx); |
4682ae04 | 158 | static tree decl_for_component_ref (tree); |
4f588890 | 159 | static int write_dependence_p (const_rtx, const_rtx, int); |
4682ae04 | 160 | |
aa317c97 | 161 | static void memory_modified_1 (rtx, const_rtx, void *); |
9ae8ffe7 JL |
162 | |
163 | /* Set up all info needed to perform alias analysis on memory references. */ | |
164 | ||
d4b60170 | 165 | /* Returns the size in bytes of the mode of X. */ |
9ae8ffe7 JL |
166 | #define SIZE_FOR_MODE(X) (GET_MODE_SIZE (GET_MODE (X))) |
167 | ||
ea64ef27 | 168 | /* Cap the number of passes we make over the insns propagating alias |
131db6b8 SB |
169 | information through set chains. |
170 | ??? 10 is a completely arbitrary choice. This should be based on the | |
171 | maximum loop depth in the CFG, but we do not have this information | |
172 | available (even if current_loops _is_ available). */ | |
ea64ef27 | 173 | #define MAX_ALIAS_LOOP_PASSES 10 |
ca7fd9cd | 174 | |
9ae8ffe7 JL |
175 | /* reg_base_value[N] gives an address to which register N is related. |
176 | If all sets after the first add or subtract to the current value | |
177 | or otherwise modify it so it does not point to a different top level | |
178 | object, reg_base_value[N] is equal to the address part of the source | |
2a2c8203 JC |
179 | of the first set. |
180 | ||
181 | A base address can be an ADDRESS, SYMBOL_REF, or LABEL_REF. ADDRESS | |
9fc37b2b | 182 | expressions represent three types of base: |
b3b5ad95 | 183 | |
9fc37b2b RS |
184 | 1. incoming arguments. There is just one ADDRESS to represent all |
185 | arguments, since we do not know at this level whether accesses | |
186 | based on different arguments can alias. The ADDRESS has id 0. | |
b3b5ad95 | 187 | |
9fc37b2b RS |
188 | 2. stack_pointer_rtx, frame_pointer_rtx, hard_frame_pointer_rtx |
189 | (if distinct from frame_pointer_rtx) and arg_pointer_rtx. | |
190 | Each of these rtxes has a separate ADDRESS associated with it, | |
191 | each with a negative id. | |
192 | ||
193 | GCC is (and is required to be) precise in which register it | |
194 | chooses to access a particular region of stack. We can therefore | |
195 | assume that accesses based on one of these rtxes do not alias | |
196 | accesses based on another of these rtxes. | |
197 | ||
198 | 3. bases that are derived from malloc()ed memory (REG_NOALIAS). | |
199 | Each such piece of memory has a separate ADDRESS associated | |
200 | with it, each with an id greater than 0. | |
201 | ||
202 | Accesses based on one ADDRESS do not alias accesses based on other | |
203 | ADDRESSes. Accesses based on ADDRESSes in groups (2) and (3) do not | |
204 | alias globals either; the ADDRESSes have Pmode to indicate this. | |
205 | The ADDRESS in group (1) _may_ alias globals; it has VOIDmode to | |
206 | indicate this. */ | |
2a2c8203 | 207 | |
9771b263 | 208 | static GTY(()) vec<rtx, va_gc> *reg_base_value; |
ac606739 | 209 | static rtx *new_reg_base_value; |
c582d54a | 210 | |
9fc37b2b RS |
211 | /* The single VOIDmode ADDRESS that represents all argument bases. |
212 | It has id 0. */ | |
213 | static GTY(()) rtx arg_base_value; | |
214 | ||
215 | /* Used to allocate unique ids to each REG_NOALIAS ADDRESS. */ | |
216 | static int unique_id; | |
217 | ||
c582d54a JH |
218 | /* We preserve the copy of old array around to avoid amount of garbage |
219 | produced. About 8% of garbage produced were attributed to this | |
220 | array. */ | |
9771b263 | 221 | static GTY((deletable)) vec<rtx, va_gc> *old_reg_base_value; |
d4b60170 | 222 | |
9e412ca3 RS |
223 | /* Values of XINT (address, 0) of Pmode ADDRESS rtxes for special |
224 | registers. */ | |
225 | #define UNIQUE_BASE_VALUE_SP -1 | |
226 | #define UNIQUE_BASE_VALUE_ARGP -2 | |
227 | #define UNIQUE_BASE_VALUE_FP -3 | |
228 | #define UNIQUE_BASE_VALUE_HFP -4 | |
229 | ||
7bf84454 RS |
230 | #define static_reg_base_value \ |
231 | (this_target_rtl->x_static_reg_base_value) | |
bf1660a6 | 232 | |
9771b263 DN |
233 | #define REG_BASE_VALUE(X) \ |
234 | (REGNO (X) < vec_safe_length (reg_base_value) \ | |
235 | ? (*reg_base_value)[REGNO (X)] : 0) | |
9ae8ffe7 | 236 | |
c13e8210 | 237 | /* Vector indexed by N giving the initial (unchanging) value known for |
9ff3c7ca | 238 | pseudo-register N. This vector is initialized in init_alias_analysis, |
bb1acb3e | 239 | and does not change until end_alias_analysis is called. */ |
9771b263 | 240 | static GTY(()) vec<rtx, va_gc> *reg_known_value; |
9ae8ffe7 JL |
241 | |
242 | /* Vector recording for each reg_known_value whether it is due to a | |
243 | REG_EQUIV note. Future passes (viz., reload) may replace the | |
244 | pseudo with the equivalent expression and so we account for the | |
ac3d9668 RK |
245 | dependences that would be introduced if that happens. |
246 | ||
247 | The REG_EQUIV notes created in assign_parms may mention the arg | |
248 | pointer, and there are explicit insns in the RTL that modify the | |
249 | arg pointer. Thus we must ensure that such insns don't get | |
250 | scheduled across each other because that would invalidate the | |
251 | REG_EQUIV notes. One could argue that the REG_EQUIV notes are | |
252 | wrong, but solving the problem in the scheduler will likely give | |
253 | better code, so we do it here. */ | |
9ff3c7ca | 254 | static sbitmap reg_known_equiv_p; |
9ae8ffe7 | 255 | |
2a2c8203 JC |
256 | /* True when scanning insns from the start of the rtl to the |
257 | NOTE_INSN_FUNCTION_BEG note. */ | |
83bbd9b6 | 258 | static bool copying_arguments; |
9ae8ffe7 | 259 | |
1a5640b4 | 260 | |
3932261a | 261 | /* The splay-tree used to store the various alias set entries. */ |
9771b263 | 262 | static GTY (()) vec<alias_set_entry, va_gc> *alias_sets; |
ac3d9668 | 263 | \f |
55b34b5f RG |
264 | /* Build a decomposed reference object for querying the alias-oracle |
265 | from the MEM rtx and store it in *REF. | |
266 | Returns false if MEM is not suitable for the alias-oracle. */ | |
267 | ||
268 | static bool | |
269 | ao_ref_from_mem (ao_ref *ref, const_rtx mem) | |
270 | { | |
271 | tree expr = MEM_EXPR (mem); | |
272 | tree base; | |
273 | ||
274 | if (!expr) | |
275 | return false; | |
276 | ||
277 | ao_ref_init (ref, expr); | |
278 | ||
279 | /* Get the base of the reference and see if we have to reject or | |
280 | adjust it. */ | |
281 | base = ao_ref_base (ref); | |
282 | if (base == NULL_TREE) | |
283 | return false; | |
284 | ||
ef7a9fb8 RB |
285 | /* The tree oracle doesn't like bases that are neither decls |
286 | nor indirect references of SSA names. */ | |
287 | if (!(DECL_P (base) | |
288 | || (TREE_CODE (base) == MEM_REF | |
289 | && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME) | |
290 | || (TREE_CODE (base) == TARGET_MEM_REF | |
291 | && TREE_CODE (TMR_BASE (base)) == SSA_NAME))) | |
d15adbeb | 292 | return false; |
55b34b5f RG |
293 | |
294 | /* If this is a reference based on a partitioned decl replace the | |
ef7a9fb8 | 295 | base with a MEM_REF of the pointer representative we |
55b34b5f RG |
296 | created during stack slot partitioning. */ |
297 | if (TREE_CODE (base) == VAR_DECL | |
ef7a9fb8 | 298 | && ! is_global_var (base) |
55b34b5f RG |
299 | && cfun->gimple_df->decls_to_pointers != NULL) |
300 | { | |
301 | void *namep; | |
302 | namep = pointer_map_contains (cfun->gimple_df->decls_to_pointers, base); | |
303 | if (namep) | |
70f34814 | 304 | ref->base = build_simple_mem_ref (*(tree *)namep); |
d15adbeb | 305 | } |
55b34b5f RG |
306 | |
307 | ref->ref_alias_set = MEM_ALIAS_SET (mem); | |
308 | ||
f68396a1 RG |
309 | /* If MEM_OFFSET or MEM_SIZE are unknown what we got from MEM_EXPR |
310 | is conservative, so trust it. */ | |
527210c4 | 311 | if (!MEM_OFFSET_KNOWN_P (mem) |
f5541398 | 312 | || !MEM_SIZE_KNOWN_P (mem)) |
f68396a1 | 313 | return true; |
366f945f | 314 | |
b0e96404 RG |
315 | /* If the base decl is a parameter we can have negative MEM_OFFSET in |
316 | case of promoted subregs on bigendian targets. Trust the MEM_EXPR | |
317 | here. */ | |
527210c4 RS |
318 | if (MEM_OFFSET (mem) < 0 |
319 | && (MEM_SIZE (mem) + MEM_OFFSET (mem)) * BITS_PER_UNIT == ref->size) | |
b0e96404 RG |
320 | return true; |
321 | ||
f68396a1 RG |
322 | /* Otherwise continue and refine size and offset we got from analyzing |
323 | MEM_EXPR by using MEM_SIZE and MEM_OFFSET. */ | |
324 | ||
527210c4 | 325 | ref->offset += MEM_OFFSET (mem) * BITS_PER_UNIT; |
f5541398 | 326 | ref->size = MEM_SIZE (mem) * BITS_PER_UNIT; |
b0e96404 RG |
327 | |
328 | /* The MEM may extend into adjacent fields, so adjust max_size if | |
329 | necessary. */ | |
330 | if (ref->max_size != -1 | |
331 | && ref->size > ref->max_size) | |
332 | ref->max_size = ref->size; | |
333 | ||
334 | /* If MEM_OFFSET and MEM_SIZE get us outside of the base object of | |
335 | the MEM_EXPR punt. This happens for STRICT_ALIGNMENT targets a lot. */ | |
336 | if (MEM_EXPR (mem) != get_spill_slot_decl (false) | |
337 | && (ref->offset < 0 | |
338 | || (DECL_P (ref->base) | |
339 | && (!host_integerp (DECL_SIZE (ref->base), 1) | |
340 | || (TREE_INT_CST_LOW (DECL_SIZE ((ref->base))) | |
341 | < (unsigned HOST_WIDE_INT)(ref->offset + ref->size)))))) | |
342 | return false; | |
55b34b5f RG |
343 | |
344 | return true; | |
345 | } | |
346 | ||
347 | /* Query the alias-oracle on whether the two memory rtx X and MEM may | |
348 | alias. If TBAA_P is set also apply TBAA. Returns true if the | |
349 | two rtxen may alias, false otherwise. */ | |
350 | ||
351 | static bool | |
352 | rtx_refs_may_alias_p (const_rtx x, const_rtx mem, bool tbaa_p) | |
353 | { | |
354 | ao_ref ref1, ref2; | |
355 | ||
356 | if (!ao_ref_from_mem (&ref1, x) | |
357 | || !ao_ref_from_mem (&ref2, mem)) | |
358 | return true; | |
359 | ||
55e3bc4c RG |
360 | return refs_may_alias_p_1 (&ref1, &ref2, |
361 | tbaa_p | |
362 | && MEM_ALIAS_SET (x) != 0 | |
363 | && MEM_ALIAS_SET (mem) != 0); | |
55b34b5f RG |
364 | } |
365 | ||
3932261a MM |
366 | /* Returns a pointer to the alias set entry for ALIAS_SET, if there is |
367 | such an entry, or NULL otherwise. */ | |
368 | ||
9ddb66ca | 369 | static inline alias_set_entry |
4862826d | 370 | get_alias_set_entry (alias_set_type alias_set) |
3932261a | 371 | { |
9771b263 | 372 | return (*alias_sets)[alias_set]; |
3932261a MM |
373 | } |
374 | ||
ac3d9668 RK |
375 | /* Returns nonzero if the alias sets for MEM1 and MEM2 are such that |
376 | the two MEMs cannot alias each other. */ | |
3932261a | 377 | |
9ddb66ca | 378 | static inline int |
4f588890 | 379 | mems_in_disjoint_alias_sets_p (const_rtx mem1, const_rtx mem2) |
3932261a | 380 | { |
3932261a MM |
381 | /* Perform a basic sanity check. Namely, that there are no alias sets |
382 | if we're not using strict aliasing. This helps to catch bugs | |
383 | whereby someone uses PUT_CODE, but doesn't clear MEM_ALIAS_SET, or | |
384 | where a MEM is allocated in some way other than by the use of | |
385 | gen_rtx_MEM, and the MEM_ALIAS_SET is not cleared. If we begin to | |
386 | use alias sets to indicate that spilled registers cannot alias each | |
387 | other, we might need to remove this check. */ | |
298e6adc NS |
388 | gcc_assert (flag_strict_aliasing |
389 | || (!MEM_ALIAS_SET (mem1) && !MEM_ALIAS_SET (mem2))); | |
3932261a | 390 | |
1da68f56 RK |
391 | return ! alias_sets_conflict_p (MEM_ALIAS_SET (mem1), MEM_ALIAS_SET (mem2)); |
392 | } | |
3932261a | 393 | |
1da68f56 RK |
394 | /* Insert the NODE into the splay tree given by DATA. Used by |
395 | record_alias_subset via splay_tree_foreach. */ | |
396 | ||
397 | static int | |
4682ae04 | 398 | insert_subset_children (splay_tree_node node, void *data) |
1da68f56 RK |
399 | { |
400 | splay_tree_insert ((splay_tree) data, node->key, node->value); | |
401 | ||
402 | return 0; | |
403 | } | |
404 | ||
c58936b6 DB |
405 | /* Return true if the first alias set is a subset of the second. */ |
406 | ||
407 | bool | |
4862826d | 408 | alias_set_subset_of (alias_set_type set1, alias_set_type set2) |
c58936b6 DB |
409 | { |
410 | alias_set_entry ase; | |
411 | ||
412 | /* Everything is a subset of the "aliases everything" set. */ | |
413 | if (set2 == 0) | |
414 | return true; | |
415 | ||
416 | /* Otherwise, check if set1 is a subset of set2. */ | |
417 | ase = get_alias_set_entry (set2); | |
418 | if (ase != 0 | |
038a39d1 | 419 | && (ase->has_zero_child |
a7a512be RG |
420 | || splay_tree_lookup (ase->children, |
421 | (splay_tree_key) set1))) | |
c58936b6 DB |
422 | return true; |
423 | return false; | |
424 | } | |
425 | ||
1da68f56 RK |
426 | /* Return 1 if the two specified alias sets may conflict. */ |
427 | ||
428 | int | |
4862826d | 429 | alias_sets_conflict_p (alias_set_type set1, alias_set_type set2) |
1da68f56 RK |
430 | { |
431 | alias_set_entry ase; | |
432 | ||
836f7794 EB |
433 | /* The easy case. */ |
434 | if (alias_sets_must_conflict_p (set1, set2)) | |
1da68f56 | 435 | return 1; |
3932261a | 436 | |
3bdf5ad1 | 437 | /* See if the first alias set is a subset of the second. */ |
1da68f56 | 438 | ase = get_alias_set_entry (set1); |
2bf105ab RK |
439 | if (ase != 0 |
440 | && (ase->has_zero_child | |
441 | || splay_tree_lookup (ase->children, | |
1da68f56 RK |
442 | (splay_tree_key) set2))) |
443 | return 1; | |
3932261a MM |
444 | |
445 | /* Now do the same, but with the alias sets reversed. */ | |
1da68f56 | 446 | ase = get_alias_set_entry (set2); |
2bf105ab RK |
447 | if (ase != 0 |
448 | && (ase->has_zero_child | |
449 | || splay_tree_lookup (ase->children, | |
1da68f56 RK |
450 | (splay_tree_key) set1))) |
451 | return 1; | |
3932261a | 452 | |
1da68f56 | 453 | /* The two alias sets are distinct and neither one is the |
836f7794 | 454 | child of the other. Therefore, they cannot conflict. */ |
1da68f56 | 455 | return 0; |
3932261a | 456 | } |
5399d643 | 457 | |
836f7794 | 458 | /* Return 1 if the two specified alias sets will always conflict. */ |
5399d643 JW |
459 | |
460 | int | |
4862826d | 461 | alias_sets_must_conflict_p (alias_set_type set1, alias_set_type set2) |
5399d643 JW |
462 | { |
463 | if (set1 == 0 || set2 == 0 || set1 == set2) | |
464 | return 1; | |
465 | ||
466 | return 0; | |
467 | } | |
468 | ||
1da68f56 RK |
469 | /* Return 1 if any MEM object of type T1 will always conflict (using the |
470 | dependency routines in this file) with any MEM object of type T2. | |
471 | This is used when allocating temporary storage. If T1 and/or T2 are | |
472 | NULL_TREE, it means we know nothing about the storage. */ | |
473 | ||
474 | int | |
4682ae04 | 475 | objects_must_conflict_p (tree t1, tree t2) |
1da68f56 | 476 | { |
4862826d | 477 | alias_set_type set1, set2; |
82d610ec | 478 | |
e8ea2809 RK |
479 | /* If neither has a type specified, we don't know if they'll conflict |
480 | because we may be using them to store objects of various types, for | |
481 | example the argument and local variables areas of inlined functions. */ | |
981a4c34 | 482 | if (t1 == 0 && t2 == 0) |
e8ea2809 RK |
483 | return 0; |
484 | ||
1da68f56 RK |
485 | /* If they are the same type, they must conflict. */ |
486 | if (t1 == t2 | |
487 | /* Likewise if both are volatile. */ | |
488 | || (t1 != 0 && TYPE_VOLATILE (t1) && t2 != 0 && TYPE_VOLATILE (t2))) | |
489 | return 1; | |
490 | ||
82d610ec RK |
491 | set1 = t1 ? get_alias_set (t1) : 0; |
492 | set2 = t2 ? get_alias_set (t2) : 0; | |
1da68f56 | 493 | |
836f7794 EB |
494 | /* We can't use alias_sets_conflict_p because we must make sure |
495 | that every subtype of t1 will conflict with every subtype of | |
82d610ec RK |
496 | t2 for which a pair of subobjects of these respective subtypes |
497 | overlaps on the stack. */ | |
836f7794 | 498 | return alias_sets_must_conflict_p (set1, set2); |
1da68f56 RK |
499 | } |
500 | \f | |
2039d7aa RH |
501 | /* Return true if all nested component references handled by |
502 | get_inner_reference in T are such that we should use the alias set | |
503 | provided by the object at the heart of T. | |
504 | ||
505 | This is true for non-addressable components (which don't have their | |
506 | own alias set), as well as components of objects in alias set zero. | |
507 | This later point is a special case wherein we wish to override the | |
508 | alias set used by the component, but we don't have per-FIELD_DECL | |
509 | assignable alias sets. */ | |
510 | ||
511 | bool | |
22ea9ec0 | 512 | component_uses_parent_alias_set (const_tree t) |
6e24b709 | 513 | { |
afe84921 RH |
514 | while (1) |
515 | { | |
2039d7aa | 516 | /* If we're at the end, it vacuously uses its own alias set. */ |
afe84921 | 517 | if (!handled_component_p (t)) |
2039d7aa | 518 | return false; |
afe84921 RH |
519 | |
520 | switch (TREE_CODE (t)) | |
521 | { | |
522 | case COMPONENT_REF: | |
523 | if (DECL_NONADDRESSABLE_P (TREE_OPERAND (t, 1))) | |
2039d7aa | 524 | return true; |
afe84921 RH |
525 | break; |
526 | ||
527 | case ARRAY_REF: | |
528 | case ARRAY_RANGE_REF: | |
529 | if (TYPE_NONALIASED_COMPONENT (TREE_TYPE (TREE_OPERAND (t, 0)))) | |
2039d7aa | 530 | return true; |
afe84921 RH |
531 | break; |
532 | ||
533 | case REALPART_EXPR: | |
534 | case IMAGPART_EXPR: | |
535 | break; | |
536 | ||
537 | default: | |
538 | /* Bitfields and casts are never addressable. */ | |
2039d7aa | 539 | return true; |
afe84921 RH |
540 | } |
541 | ||
542 | t = TREE_OPERAND (t, 0); | |
2039d7aa RH |
543 | if (get_alias_set (TREE_TYPE (t)) == 0) |
544 | return true; | |
afe84921 | 545 | } |
6e24b709 RK |
546 | } |
547 | ||
5006671f RG |
548 | /* Return the alias set for the memory pointed to by T, which may be |
549 | either a type or an expression. Return -1 if there is nothing | |
550 | special about dereferencing T. */ | |
551 | ||
552 | static alias_set_type | |
553 | get_deref_alias_set_1 (tree t) | |
554 | { | |
555 | /* If we're not doing any alias analysis, just assume everything | |
556 | aliases everything else. */ | |
557 | if (!flag_strict_aliasing) | |
558 | return 0; | |
559 | ||
5b21f0f3 | 560 | /* All we care about is the type. */ |
5006671f | 561 | if (! TYPE_P (t)) |
5b21f0f3 | 562 | t = TREE_TYPE (t); |
5006671f RG |
563 | |
564 | /* If we have an INDIRECT_REF via a void pointer, we don't | |
565 | know anything about what that might alias. Likewise if the | |
566 | pointer is marked that way. */ | |
567 | if (TREE_CODE (TREE_TYPE (t)) == VOID_TYPE | |
568 | || TYPE_REF_CAN_ALIAS_ALL (t)) | |
569 | return 0; | |
570 | ||
571 | return -1; | |
572 | } | |
573 | ||
574 | /* Return the alias set for the memory pointed to by T, which may be | |
575 | either a type or an expression. */ | |
576 | ||
577 | alias_set_type | |
578 | get_deref_alias_set (tree t) | |
579 | { | |
580 | alias_set_type set = get_deref_alias_set_1 (t); | |
581 | ||
582 | /* Fall back to the alias-set of the pointed-to type. */ | |
583 | if (set == -1) | |
584 | { | |
585 | if (! TYPE_P (t)) | |
586 | t = TREE_TYPE (t); | |
587 | set = get_alias_set (TREE_TYPE (t)); | |
588 | } | |
589 | ||
590 | return set; | |
591 | } | |
592 | ||
3bdf5ad1 RK |
593 | /* Return the alias set for T, which may be either a type or an |
594 | expression. Call language-specific routine for help, if needed. */ | |
595 | ||
4862826d | 596 | alias_set_type |
4682ae04 | 597 | get_alias_set (tree t) |
3bdf5ad1 | 598 | { |
4862826d | 599 | alias_set_type set; |
3bdf5ad1 RK |
600 | |
601 | /* If we're not doing any alias analysis, just assume everything | |
602 | aliases everything else. Also return 0 if this or its type is | |
603 | an error. */ | |
604 | if (! flag_strict_aliasing || t == error_mark_node | |
605 | || (! TYPE_P (t) | |
606 | && (TREE_TYPE (t) == 0 || TREE_TYPE (t) == error_mark_node))) | |
607 | return 0; | |
608 | ||
609 | /* We can be passed either an expression or a type. This and the | |
f47e9b4e RK |
610 | language-specific routine may make mutually-recursive calls to each other |
611 | to figure out what to do. At each juncture, we see if this is a tree | |
612 | that the language may need to handle specially. First handle things that | |
738cc472 | 613 | aren't types. */ |
f824e5c3 | 614 | if (! TYPE_P (t)) |
3bdf5ad1 | 615 | { |
ebcc3d93 | 616 | tree inner; |
738cc472 | 617 | |
70f34814 RG |
618 | /* Give the language a chance to do something with this tree |
619 | before we look at it. */ | |
8ac61af7 | 620 | STRIP_NOPS (t); |
ae2bcd98 | 621 | set = lang_hooks.get_alias_set (t); |
8ac61af7 RK |
622 | if (set != -1) |
623 | return set; | |
624 | ||
70f34814 | 625 | /* Get the base object of the reference. */ |
ebcc3d93 | 626 | inner = t; |
6fce44af | 627 | while (handled_component_p (inner)) |
738cc472 | 628 | { |
70f34814 RG |
629 | /* If there is a VIEW_CONVERT_EXPR in the chain we cannot use |
630 | the type of any component references that wrap it to | |
631 | determine the alias-set. */ | |
632 | if (TREE_CODE (inner) == VIEW_CONVERT_EXPR) | |
633 | t = TREE_OPERAND (inner, 0); | |
6fce44af | 634 | inner = TREE_OPERAND (inner, 0); |
738cc472 RK |
635 | } |
636 | ||
70f34814 RG |
637 | /* Handle pointer dereferences here, they can override the |
638 | alias-set. */ | |
1b096a0a | 639 | if (INDIRECT_REF_P (inner)) |
738cc472 | 640 | { |
5006671f RG |
641 | set = get_deref_alias_set_1 (TREE_OPERAND (inner, 0)); |
642 | if (set != -1) | |
643 | return set; | |
738cc472 | 644 | } |
4b228e61 RG |
645 | else if (TREE_CODE (inner) == TARGET_MEM_REF) |
646 | return get_deref_alias_set (TMR_OFFSET (inner)); | |
70f34814 RG |
647 | else if (TREE_CODE (inner) == MEM_REF) |
648 | { | |
649 | set = get_deref_alias_set_1 (TREE_OPERAND (inner, 1)); | |
650 | if (set != -1) | |
651 | return set; | |
652 | } | |
653 | ||
654 | /* If the innermost reference is a MEM_REF that has a | |
655 | conversion embedded treat it like a VIEW_CONVERT_EXPR above, | |
656 | using the memory access type for determining the alias-set. */ | |
657 | if (TREE_CODE (inner) == MEM_REF | |
7be7d292 EB |
658 | && TYPE_MAIN_VARIANT (TREE_TYPE (inner)) |
659 | != TYPE_MAIN_VARIANT | |
660 | (TREE_TYPE (TREE_TYPE (TREE_OPERAND (inner, 1))))) | |
70f34814 | 661 | return get_deref_alias_set (TREE_OPERAND (inner, 1)); |
738cc472 RK |
662 | |
663 | /* Otherwise, pick up the outermost object that we could have a pointer | |
6fce44af | 664 | to, processing conversions as above. */ |
2039d7aa | 665 | while (component_uses_parent_alias_set (t)) |
f47e9b4e | 666 | { |
6fce44af | 667 | t = TREE_OPERAND (t, 0); |
8ac61af7 RK |
668 | STRIP_NOPS (t); |
669 | } | |
f824e5c3 | 670 | |
738cc472 RK |
671 | /* If we've already determined the alias set for a decl, just return |
672 | it. This is necessary for C++ anonymous unions, whose component | |
673 | variables don't look like union members (boo!). */ | |
5755cd38 | 674 | if (TREE_CODE (t) == VAR_DECL |
3c0cb5de | 675 | && DECL_RTL_SET_P (t) && MEM_P (DECL_RTL (t))) |
5755cd38 JM |
676 | return MEM_ALIAS_SET (DECL_RTL (t)); |
677 | ||
f824e5c3 RK |
678 | /* Now all we care about is the type. */ |
679 | t = TREE_TYPE (t); | |
3bdf5ad1 RK |
680 | } |
681 | ||
3bdf5ad1 | 682 | /* Variant qualifiers don't affect the alias set, so get the main |
daad0278 | 683 | variant. */ |
3bdf5ad1 | 684 | t = TYPE_MAIN_VARIANT (t); |
daad0278 RG |
685 | |
686 | /* Always use the canonical type as well. If this is a type that | |
687 | requires structural comparisons to identify compatible types | |
688 | use alias set zero. */ | |
689 | if (TYPE_STRUCTURAL_EQUALITY_P (t)) | |
cb9c2485 JM |
690 | { |
691 | /* Allow the language to specify another alias set for this | |
692 | type. */ | |
693 | set = lang_hooks.get_alias_set (t); | |
694 | if (set != -1) | |
695 | return set; | |
696 | return 0; | |
697 | } | |
7be7d292 | 698 | |
daad0278 | 699 | t = TYPE_CANONICAL (t); |
7be7d292 | 700 | |
96d91dcf RG |
701 | /* The canonical type should not require structural equality checks. */ |
702 | gcc_checking_assert (!TYPE_STRUCTURAL_EQUALITY_P (t)); | |
daad0278 RG |
703 | |
704 | /* If this is a type with a known alias set, return it. */ | |
738cc472 | 705 | if (TYPE_ALIAS_SET_KNOWN_P (t)) |
3bdf5ad1 RK |
706 | return TYPE_ALIAS_SET (t); |
707 | ||
36784d0e RG |
708 | /* We don't want to set TYPE_ALIAS_SET for incomplete types. */ |
709 | if (!COMPLETE_TYPE_P (t)) | |
710 | { | |
711 | /* For arrays with unknown size the conservative answer is the | |
712 | alias set of the element type. */ | |
713 | if (TREE_CODE (t) == ARRAY_TYPE) | |
714 | return get_alias_set (TREE_TYPE (t)); | |
715 | ||
716 | /* But return zero as a conservative answer for incomplete types. */ | |
717 | return 0; | |
718 | } | |
719 | ||
3bdf5ad1 | 720 | /* See if the language has special handling for this type. */ |
ae2bcd98 | 721 | set = lang_hooks.get_alias_set (t); |
8ac61af7 | 722 | if (set != -1) |
738cc472 | 723 | return set; |
2bf105ab | 724 | |
3bdf5ad1 RK |
725 | /* There are no objects of FUNCTION_TYPE, so there's no point in |
726 | using up an alias set for them. (There are, of course, pointers | |
727 | and references to functions, but that's different.) */ | |
7be7d292 | 728 | else if (TREE_CODE (t) == FUNCTION_TYPE || TREE_CODE (t) == METHOD_TYPE) |
3bdf5ad1 | 729 | set = 0; |
74d86f4f RH |
730 | |
731 | /* Unless the language specifies otherwise, let vector types alias | |
732 | their components. This avoids some nasty type punning issues in | |
733 | normal usage. And indeed lets vectors be treated more like an | |
734 | array slice. */ | |
735 | else if (TREE_CODE (t) == VECTOR_TYPE) | |
736 | set = get_alias_set (TREE_TYPE (t)); | |
737 | ||
4653cae5 RG |
738 | /* Unless the language specifies otherwise, treat array types the |
739 | same as their components. This avoids the asymmetry we get | |
740 | through recording the components. Consider accessing a | |
741 | character(kind=1) through a reference to a character(kind=1)[1:1]. | |
742 | Or consider if we want to assign integer(kind=4)[0:D.1387] and | |
743 | integer(kind=4)[4] the same alias set or not. | |
744 | Just be pragmatic here and make sure the array and its element | |
745 | type get the same alias set assigned. */ | |
7be7d292 | 746 | else if (TREE_CODE (t) == ARRAY_TYPE && !TYPE_NONALIASED_COMPONENT (t)) |
4653cae5 RG |
747 | set = get_alias_set (TREE_TYPE (t)); |
748 | ||
0ceb0201 RG |
749 | /* From the former common C and C++ langhook implementation: |
750 | ||
751 | Unfortunately, there is no canonical form of a pointer type. | |
752 | In particular, if we have `typedef int I', then `int *', and | |
753 | `I *' are different types. So, we have to pick a canonical | |
754 | representative. We do this below. | |
755 | ||
756 | Technically, this approach is actually more conservative that | |
757 | it needs to be. In particular, `const int *' and `int *' | |
758 | should be in different alias sets, according to the C and C++ | |
759 | standard, since their types are not the same, and so, | |
760 | technically, an `int **' and `const int **' cannot point at | |
761 | the same thing. | |
762 | ||
763 | But, the standard is wrong. In particular, this code is | |
764 | legal C++: | |
765 | ||
766 | int *ip; | |
767 | int **ipp = &ip; | |
768 | const int* const* cipp = ipp; | |
769 | And, it doesn't make sense for that to be legal unless you | |
770 | can dereference IPP and CIPP. So, we ignore cv-qualifiers on | |
771 | the pointed-to types. This issue has been reported to the | |
772 | C++ committee. | |
773 | ||
774 | In addition to the above canonicalization issue, with LTO | |
775 | we should also canonicalize `T (*)[]' to `T *' avoiding | |
776 | alias issues with pointer-to element types and pointer-to | |
777 | array types. | |
778 | ||
779 | Likewise we need to deal with the situation of incomplete | |
780 | pointed-to types and make `*(struct X **)&a' and | |
781 | `*(struct X {} **)&a' alias. Otherwise we will have to | |
782 | guarantee that all pointer-to incomplete type variants | |
783 | will be replaced by pointer-to complete type variants if | |
784 | they are available. | |
785 | ||
786 | With LTO the convenient situation of using `void *' to | |
787 | access and store any pointer type will also become | |
788 | more apparent (and `void *' is just another pointer-to | |
789 | incomplete type). Assigning alias-set zero to `void *' | |
790 | and all pointer-to incomplete types is a not appealing | |
791 | solution. Assigning an effective alias-set zero only | |
792 | affecting pointers might be - by recording proper subset | |
793 | relationships of all pointer alias-sets. | |
794 | ||
795 | Pointer-to function types are another grey area which | |
796 | needs caution. Globbing them all into one alias-set | |
797 | or the above effective zero set would work. | |
798 | ||
799 | For now just assign the same alias-set to all pointers. | |
800 | That's simple and avoids all the above problems. */ | |
801 | else if (POINTER_TYPE_P (t) | |
802 | && t != ptr_type_node) | |
96d91dcf | 803 | set = get_alias_set (ptr_type_node); |
0ceb0201 | 804 | |
7be7d292 | 805 | /* Otherwise make a new alias set for this type. */ |
3bdf5ad1 | 806 | else |
96d91dcf RG |
807 | { |
808 | /* Each canonical type gets its own alias set, so canonical types | |
809 | shouldn't form a tree. It doesn't really matter for types | |
810 | we handle specially above, so only check it where it possibly | |
811 | would result in a bogus alias set. */ | |
812 | gcc_checking_assert (TYPE_CANONICAL (t) == t); | |
813 | ||
814 | set = new_alias_set (); | |
815 | } | |
3bdf5ad1 RK |
816 | |
817 | TYPE_ALIAS_SET (t) = set; | |
2bf105ab | 818 | |
7be7d292 EB |
819 | /* If this is an aggregate type or a complex type, we must record any |
820 | component aliasing information. */ | |
1d79fd2c | 821 | if (AGGREGATE_TYPE_P (t) || TREE_CODE (t) == COMPLEX_TYPE) |
2bf105ab RK |
822 | record_component_aliases (t); |
823 | ||
3bdf5ad1 RK |
824 | return set; |
825 | } | |
826 | ||
827 | /* Return a brand-new alias set. */ | |
828 | ||
4862826d | 829 | alias_set_type |
4682ae04 | 830 | new_alias_set (void) |
3bdf5ad1 | 831 | { |
3bdf5ad1 | 832 | if (flag_strict_aliasing) |
9ddb66ca | 833 | { |
1a5640b4 | 834 | if (alias_sets == 0) |
9771b263 DN |
835 | vec_safe_push (alias_sets, (alias_set_entry) 0); |
836 | vec_safe_push (alias_sets, (alias_set_entry) 0); | |
837 | return alias_sets->length () - 1; | |
9ddb66ca | 838 | } |
3bdf5ad1 RK |
839 | else |
840 | return 0; | |
841 | } | |
3932261a | 842 | |
01d28c3f JM |
843 | /* Indicate that things in SUBSET can alias things in SUPERSET, but that |
844 | not everything that aliases SUPERSET also aliases SUBSET. For example, | |
845 | in C, a store to an `int' can alias a load of a structure containing an | |
846 | `int', and vice versa. But it can't alias a load of a 'double' member | |
847 | of the same structure. Here, the structure would be the SUPERSET and | |
848 | `int' the SUBSET. This relationship is also described in the comment at | |
849 | the beginning of this file. | |
850 | ||
851 | This function should be called only once per SUPERSET/SUBSET pair. | |
3932261a MM |
852 | |
853 | It is illegal for SUPERSET to be zero; everything is implicitly a | |
854 | subset of alias set zero. */ | |
855 | ||
794511d2 | 856 | void |
4862826d | 857 | record_alias_subset (alias_set_type superset, alias_set_type subset) |
3932261a MM |
858 | { |
859 | alias_set_entry superset_entry; | |
860 | alias_set_entry subset_entry; | |
861 | ||
f47e9b4e RK |
862 | /* It is possible in complex type situations for both sets to be the same, |
863 | in which case we can ignore this operation. */ | |
864 | if (superset == subset) | |
865 | return; | |
866 | ||
298e6adc | 867 | gcc_assert (superset); |
3932261a MM |
868 | |
869 | superset_entry = get_alias_set_entry (superset); | |
ca7fd9cd | 870 | if (superset_entry == 0) |
3932261a MM |
871 | { |
872 | /* Create an entry for the SUPERSET, so that we have a place to | |
873 | attach the SUBSET. */ | |
a9429e29 | 874 | superset_entry = ggc_alloc_cleared_alias_set_entry_d (); |
3932261a | 875 | superset_entry->alias_set = superset; |
ca7fd9cd | 876 | superset_entry->children |
a9429e29 LB |
877 | = splay_tree_new_ggc (splay_tree_compare_ints, |
878 | ggc_alloc_splay_tree_scalar_scalar_splay_tree_s, | |
879 | ggc_alloc_splay_tree_scalar_scalar_splay_tree_node_s); | |
570eb5c8 | 880 | superset_entry->has_zero_child = 0; |
9771b263 | 881 | (*alias_sets)[superset] = superset_entry; |
3932261a MM |
882 | } |
883 | ||
2bf105ab RK |
884 | if (subset == 0) |
885 | superset_entry->has_zero_child = 1; | |
886 | else | |
887 | { | |
888 | subset_entry = get_alias_set_entry (subset); | |
889 | /* If there is an entry for the subset, enter all of its children | |
890 | (if they are not already present) as children of the SUPERSET. */ | |
ca7fd9cd | 891 | if (subset_entry) |
2bf105ab RK |
892 | { |
893 | if (subset_entry->has_zero_child) | |
894 | superset_entry->has_zero_child = 1; | |
d4b60170 | 895 | |
2bf105ab RK |
896 | splay_tree_foreach (subset_entry->children, insert_subset_children, |
897 | superset_entry->children); | |
898 | } | |
3932261a | 899 | |
2bf105ab | 900 | /* Enter the SUBSET itself as a child of the SUPERSET. */ |
ca7fd9cd | 901 | splay_tree_insert (superset_entry->children, |
2bf105ab RK |
902 | (splay_tree_key) subset, 0); |
903 | } | |
3932261a MM |
904 | } |
905 | ||
a0c33338 RK |
906 | /* Record that component types of TYPE, if any, are part of that type for |
907 | aliasing purposes. For record types, we only record component types | |
b5487346 EB |
908 | for fields that are not marked non-addressable. For array types, we |
909 | only record the component type if it is not marked non-aliased. */ | |
a0c33338 RK |
910 | |
911 | void | |
4682ae04 | 912 | record_component_aliases (tree type) |
a0c33338 | 913 | { |
4862826d | 914 | alias_set_type superset = get_alias_set (type); |
a0c33338 RK |
915 | tree field; |
916 | ||
917 | if (superset == 0) | |
918 | return; | |
919 | ||
920 | switch (TREE_CODE (type)) | |
921 | { | |
a0c33338 RK |
922 | case RECORD_TYPE: |
923 | case UNION_TYPE: | |
924 | case QUAL_UNION_TYPE: | |
6614fd40 | 925 | /* Recursively record aliases for the base classes, if there are any. */ |
fa743e8c | 926 | if (TYPE_BINFO (type)) |
ca7fd9cd KH |
927 | { |
928 | int i; | |
fa743e8c | 929 | tree binfo, base_binfo; |
c22cacf3 | 930 | |
fa743e8c NS |
931 | for (binfo = TYPE_BINFO (type), i = 0; |
932 | BINFO_BASE_ITERATE (binfo, i, base_binfo); i++) | |
933 | record_alias_subset (superset, | |
934 | get_alias_set (BINFO_TYPE (base_binfo))); | |
ca7fd9cd | 935 | } |
910ad8de | 936 | for (field = TYPE_FIELDS (type); field != 0; field = DECL_CHAIN (field)) |
b5487346 | 937 | if (TREE_CODE (field) == FIELD_DECL && !DECL_NONADDRESSABLE_P (field)) |
2bf105ab | 938 | record_alias_subset (superset, get_alias_set (TREE_TYPE (field))); |
a0c33338 RK |
939 | break; |
940 | ||
1d79fd2c JW |
941 | case COMPLEX_TYPE: |
942 | record_alias_subset (superset, get_alias_set (TREE_TYPE (type))); | |
943 | break; | |
944 | ||
4653cae5 RG |
945 | /* VECTOR_TYPE and ARRAY_TYPE share the alias set with their |
946 | element type. */ | |
947 | ||
a0c33338 RK |
948 | default: |
949 | break; | |
950 | } | |
951 | } | |
952 | ||
3bdf5ad1 RK |
953 | /* Allocate an alias set for use in storing and reading from the varargs |
954 | spill area. */ | |
955 | ||
4862826d | 956 | static GTY(()) alias_set_type varargs_set = -1; |
f103e34d | 957 | |
4862826d | 958 | alias_set_type |
4682ae04 | 959 | get_varargs_alias_set (void) |
3bdf5ad1 | 960 | { |
cd3ce9b4 JM |
961 | #if 1 |
962 | /* We now lower VA_ARG_EXPR, and there's currently no way to attach the | |
963 | varargs alias set to an INDIRECT_REF (FIXME!), so we can't | |
964 | consistently use the varargs alias set for loads from the varargs | |
965 | area. So don't use it anywhere. */ | |
966 | return 0; | |
967 | #else | |
f103e34d GK |
968 | if (varargs_set == -1) |
969 | varargs_set = new_alias_set (); | |
3bdf5ad1 | 970 | |
f103e34d | 971 | return varargs_set; |
cd3ce9b4 | 972 | #endif |
3bdf5ad1 RK |
973 | } |
974 | ||
975 | /* Likewise, but used for the fixed portions of the frame, e.g., register | |
976 | save areas. */ | |
977 | ||
4862826d | 978 | static GTY(()) alias_set_type frame_set = -1; |
f103e34d | 979 | |
4862826d | 980 | alias_set_type |
4682ae04 | 981 | get_frame_alias_set (void) |
3bdf5ad1 | 982 | { |
f103e34d GK |
983 | if (frame_set == -1) |
984 | frame_set = new_alias_set (); | |
3bdf5ad1 | 985 | |
f103e34d | 986 | return frame_set; |
3bdf5ad1 RK |
987 | } |
988 | ||
9fc37b2b RS |
989 | /* Create a new, unique base with id ID. */ |
990 | ||
991 | static rtx | |
992 | unique_base_value (HOST_WIDE_INT id) | |
993 | { | |
994 | return gen_rtx_ADDRESS (Pmode, id); | |
995 | } | |
996 | ||
997 | /* Return true if accesses based on any other base value cannot alias | |
998 | those based on X. */ | |
999 | ||
1000 | static bool | |
1001 | unique_base_value_p (rtx x) | |
1002 | { | |
1003 | return GET_CODE (x) == ADDRESS && GET_MODE (x) == Pmode; | |
1004 | } | |
1005 | ||
1006 | /* Return true if X is known to be a base value. */ | |
1007 | ||
1008 | static bool | |
1009 | known_base_value_p (rtx x) | |
1010 | { | |
1011 | switch (GET_CODE (x)) | |
1012 | { | |
1013 | case LABEL_REF: | |
1014 | case SYMBOL_REF: | |
1015 | return true; | |
1016 | ||
1017 | case ADDRESS: | |
1018 | /* Arguments may or may not be bases; we don't know for sure. */ | |
1019 | return GET_MODE (x) != VOIDmode; | |
1020 | ||
1021 | default: | |
1022 | return false; | |
1023 | } | |
1024 | } | |
1025 | ||
2a2c8203 JC |
1026 | /* Inside SRC, the source of a SET, find a base address. */ |
1027 | ||
9ae8ffe7 | 1028 | static rtx |
4682ae04 | 1029 | find_base_value (rtx src) |
9ae8ffe7 | 1030 | { |
713f41f9 | 1031 | unsigned int regno; |
0aacc8ed | 1032 | |
53451050 RS |
1033 | #if defined (FIND_BASE_TERM) |
1034 | /* Try machine-dependent ways to find the base term. */ | |
1035 | src = FIND_BASE_TERM (src); | |
1036 | #endif | |
1037 | ||
9ae8ffe7 JL |
1038 | switch (GET_CODE (src)) |
1039 | { | |
1040 | case SYMBOL_REF: | |
1041 | case LABEL_REF: | |
1042 | return src; | |
1043 | ||
1044 | case REG: | |
fb6754f0 | 1045 | regno = REGNO (src); |
d4b60170 | 1046 | /* At the start of a function, argument registers have known base |
2a2c8203 JC |
1047 | values which may be lost later. Returning an ADDRESS |
1048 | expression here allows optimization based on argument values | |
1049 | even when the argument registers are used for other purposes. */ | |
713f41f9 BS |
1050 | if (regno < FIRST_PSEUDO_REGISTER && copying_arguments) |
1051 | return new_reg_base_value[regno]; | |
73774bc7 | 1052 | |
eaf407a5 | 1053 | /* If a pseudo has a known base value, return it. Do not do this |
9b462c42 RH |
1054 | for non-fixed hard regs since it can result in a circular |
1055 | dependency chain for registers which have values at function entry. | |
eaf407a5 JL |
1056 | |
1057 | The test above is not sufficient because the scheduler may move | |
1058 | a copy out of an arg reg past the NOTE_INSN_FUNCTION_BEGIN. */ | |
9b462c42 | 1059 | if ((regno >= FIRST_PSEUDO_REGISTER || fixed_regs[regno]) |
9771b263 | 1060 | && regno < vec_safe_length (reg_base_value)) |
83bbd9b6 RH |
1061 | { |
1062 | /* If we're inside init_alias_analysis, use new_reg_base_value | |
1063 | to reduce the number of relaxation iterations. */ | |
1afdf91c | 1064 | if (new_reg_base_value && new_reg_base_value[regno] |
6fb5fa3c | 1065 | && DF_REG_DEF_COUNT (regno) == 1) |
83bbd9b6 RH |
1066 | return new_reg_base_value[regno]; |
1067 | ||
9771b263 DN |
1068 | if ((*reg_base_value)[regno]) |
1069 | return (*reg_base_value)[regno]; | |
83bbd9b6 | 1070 | } |
73774bc7 | 1071 | |
e3f049a8 | 1072 | return 0; |
9ae8ffe7 JL |
1073 | |
1074 | case MEM: | |
1075 | /* Check for an argument passed in memory. Only record in the | |
1076 | copying-arguments block; it is too hard to track changes | |
1077 | otherwise. */ | |
1078 | if (copying_arguments | |
1079 | && (XEXP (src, 0) == arg_pointer_rtx | |
1080 | || (GET_CODE (XEXP (src, 0)) == PLUS | |
1081 | && XEXP (XEXP (src, 0), 0) == arg_pointer_rtx))) | |
9fc37b2b | 1082 | return arg_base_value; |
9ae8ffe7 JL |
1083 | return 0; |
1084 | ||
1085 | case CONST: | |
1086 | src = XEXP (src, 0); | |
1087 | if (GET_CODE (src) != PLUS && GET_CODE (src) != MINUS) | |
1088 | break; | |
d4b60170 | 1089 | |
ec5c56db | 1090 | /* ... fall through ... */ |
2a2c8203 | 1091 | |
9ae8ffe7 JL |
1092 | case PLUS: |
1093 | case MINUS: | |
2a2c8203 | 1094 | { |
ec907dd8 JL |
1095 | rtx temp, src_0 = XEXP (src, 0), src_1 = XEXP (src, 1); |
1096 | ||
0134bf2d DE |
1097 | /* If either operand is a REG that is a known pointer, then it |
1098 | is the base. */ | |
1099 | if (REG_P (src_0) && REG_POINTER (src_0)) | |
1100 | return find_base_value (src_0); | |
1101 | if (REG_P (src_1) && REG_POINTER (src_1)) | |
1102 | return find_base_value (src_1); | |
1103 | ||
ec907dd8 JL |
1104 | /* If either operand is a REG, then see if we already have |
1105 | a known value for it. */ | |
0134bf2d | 1106 | if (REG_P (src_0)) |
ec907dd8 JL |
1107 | { |
1108 | temp = find_base_value (src_0); | |
d4b60170 | 1109 | if (temp != 0) |
ec907dd8 JL |
1110 | src_0 = temp; |
1111 | } | |
1112 | ||
0134bf2d | 1113 | if (REG_P (src_1)) |
ec907dd8 JL |
1114 | { |
1115 | temp = find_base_value (src_1); | |
d4b60170 | 1116 | if (temp!= 0) |
ec907dd8 JL |
1117 | src_1 = temp; |
1118 | } | |
2a2c8203 | 1119 | |
0134bf2d DE |
1120 | /* If either base is named object or a special address |
1121 | (like an argument or stack reference), then use it for the | |
1122 | base term. */ | |
9fc37b2b | 1123 | if (src_0 != 0 && known_base_value_p (src_0)) |
0134bf2d DE |
1124 | return src_0; |
1125 | ||
9fc37b2b | 1126 | if (src_1 != 0 && known_base_value_p (src_1)) |
0134bf2d DE |
1127 | return src_1; |
1128 | ||
d4b60170 | 1129 | /* Guess which operand is the base address: |
ec907dd8 JL |
1130 | If either operand is a symbol, then it is the base. If |
1131 | either operand is a CONST_INT, then the other is the base. */ | |
481683e1 | 1132 | if (CONST_INT_P (src_1) || CONSTANT_P (src_0)) |
2a2c8203 | 1133 | return find_base_value (src_0); |
481683e1 | 1134 | else if (CONST_INT_P (src_0) || CONSTANT_P (src_1)) |
ec907dd8 JL |
1135 | return find_base_value (src_1); |
1136 | ||
9ae8ffe7 | 1137 | return 0; |
2a2c8203 JC |
1138 | } |
1139 | ||
1140 | case LO_SUM: | |
1141 | /* The standard form is (lo_sum reg sym) so look only at the | |
1142 | second operand. */ | |
1143 | return find_base_value (XEXP (src, 1)); | |
9ae8ffe7 JL |
1144 | |
1145 | case AND: | |
1146 | /* If the second operand is constant set the base | |
ec5c56db | 1147 | address to the first operand. */ |
481683e1 | 1148 | if (CONST_INT_P (XEXP (src, 1)) && INTVAL (XEXP (src, 1)) != 0) |
2a2c8203 | 1149 | return find_base_value (XEXP (src, 0)); |
9ae8ffe7 JL |
1150 | return 0; |
1151 | ||
61f0131c | 1152 | case TRUNCATE: |
5932a4d4 | 1153 | /* As we do not know which address space the pointer is referring to, we can |
d4ebfa65 BE |
1154 | handle this only if the target does not support different pointer or |
1155 | address modes depending on the address space. */ | |
1156 | if (!target_default_pointer_address_modes_p ()) | |
1157 | break; | |
61f0131c R |
1158 | if (GET_MODE_SIZE (GET_MODE (src)) < GET_MODE_SIZE (Pmode)) |
1159 | break; | |
1160 | /* Fall through. */ | |
9ae8ffe7 | 1161 | case HIGH: |
d288e53d DE |
1162 | case PRE_INC: |
1163 | case PRE_DEC: | |
1164 | case POST_INC: | |
1165 | case POST_DEC: | |
1166 | case PRE_MODIFY: | |
1167 | case POST_MODIFY: | |
2a2c8203 | 1168 | return find_base_value (XEXP (src, 0)); |
1d300e19 | 1169 | |
0aacc8ed RK |
1170 | case ZERO_EXTEND: |
1171 | case SIGN_EXTEND: /* used for NT/Alpha pointers */ | |
5932a4d4 | 1172 | /* As we do not know which address space the pointer is referring to, we can |
d4ebfa65 BE |
1173 | handle this only if the target does not support different pointer or |
1174 | address modes depending on the address space. */ | |
1175 | if (!target_default_pointer_address_modes_p ()) | |
1176 | break; | |
1177 | ||
0aacc8ed RK |
1178 | { |
1179 | rtx temp = find_base_value (XEXP (src, 0)); | |
1180 | ||
5ae6cd0d | 1181 | if (temp != 0 && CONSTANT_P (temp)) |
0aacc8ed | 1182 | temp = convert_memory_address (Pmode, temp); |
0aacc8ed RK |
1183 | |
1184 | return temp; | |
1185 | } | |
1186 | ||
1d300e19 KG |
1187 | default: |
1188 | break; | |
9ae8ffe7 JL |
1189 | } |
1190 | ||
1191 | return 0; | |
1192 | } | |
1193 | ||
9fc37b2b RS |
1194 | /* Called from init_alias_analysis indirectly through note_stores, |
1195 | or directly if DEST is a register with a REG_NOALIAS note attached. | |
1196 | SET is null in the latter case. */ | |
9ae8ffe7 | 1197 | |
d4b60170 | 1198 | /* While scanning insns to find base values, reg_seen[N] is nonzero if |
9ae8ffe7 | 1199 | register N has been set in this function. */ |
d630245f | 1200 | static sbitmap reg_seen; |
9ae8ffe7 | 1201 | |
2a2c8203 | 1202 | static void |
7bc980e1 | 1203 | record_set (rtx dest, const_rtx set, void *data ATTRIBUTE_UNUSED) |
9ae8ffe7 | 1204 | { |
b3694847 | 1205 | unsigned regno; |
9ae8ffe7 | 1206 | rtx src; |
c28b4e40 | 1207 | int n; |
9ae8ffe7 | 1208 | |
f8cfc6aa | 1209 | if (!REG_P (dest)) |
9ae8ffe7 JL |
1210 | return; |
1211 | ||
fb6754f0 | 1212 | regno = REGNO (dest); |
9ae8ffe7 | 1213 | |
9771b263 | 1214 | gcc_checking_assert (regno < reg_base_value->length ()); |
ac606739 | 1215 | |
c28b4e40 JW |
1216 | /* If this spans multiple hard registers, then we must indicate that every |
1217 | register has an unusable value. */ | |
1218 | if (regno < FIRST_PSEUDO_REGISTER) | |
66fd46b6 | 1219 | n = hard_regno_nregs[regno][GET_MODE (dest)]; |
c28b4e40 JW |
1220 | else |
1221 | n = 1; | |
1222 | if (n != 1) | |
1223 | { | |
1224 | while (--n >= 0) | |
1225 | { | |
d7c028c0 | 1226 | bitmap_set_bit (reg_seen, regno + n); |
c28b4e40 JW |
1227 | new_reg_base_value[regno + n] = 0; |
1228 | } | |
1229 | return; | |
1230 | } | |
1231 | ||
9ae8ffe7 JL |
1232 | if (set) |
1233 | { | |
1234 | /* A CLOBBER wipes out any old value but does not prevent a previously | |
1235 | unset register from acquiring a base address (i.e. reg_seen is not | |
1236 | set). */ | |
1237 | if (GET_CODE (set) == CLOBBER) | |
1238 | { | |
ec907dd8 | 1239 | new_reg_base_value[regno] = 0; |
9ae8ffe7 JL |
1240 | return; |
1241 | } | |
1242 | src = SET_SRC (set); | |
1243 | } | |
1244 | else | |
1245 | { | |
9fc37b2b | 1246 | /* There's a REG_NOALIAS note against DEST. */ |
d7c028c0 | 1247 | if (bitmap_bit_p (reg_seen, regno)) |
9ae8ffe7 | 1248 | { |
ec907dd8 | 1249 | new_reg_base_value[regno] = 0; |
9ae8ffe7 JL |
1250 | return; |
1251 | } | |
d7c028c0 | 1252 | bitmap_set_bit (reg_seen, regno); |
9fc37b2b | 1253 | new_reg_base_value[regno] = unique_base_value (unique_id++); |
9ae8ffe7 JL |
1254 | return; |
1255 | } | |
1256 | ||
5da6f168 RS |
1257 | /* If this is not the first set of REGNO, see whether the new value |
1258 | is related to the old one. There are two cases of interest: | |
1259 | ||
1260 | (1) The register might be assigned an entirely new value | |
1261 | that has the same base term as the original set. | |
1262 | ||
1263 | (2) The set might be a simple self-modification that | |
1264 | cannot change REGNO's base value. | |
1265 | ||
1266 | If neither case holds, reject the original base value as invalid. | |
1267 | Note that the following situation is not detected: | |
1268 | ||
c22cacf3 | 1269 | extern int x, y; int *p = &x; p += (&y-&x); |
5da6f168 | 1270 | |
9ae8ffe7 JL |
1271 | ANSI C does not allow computing the difference of addresses |
1272 | of distinct top level objects. */ | |
5da6f168 RS |
1273 | if (new_reg_base_value[regno] != 0 |
1274 | && find_base_value (src) != new_reg_base_value[regno]) | |
9ae8ffe7 JL |
1275 | switch (GET_CODE (src)) |
1276 | { | |
2a2c8203 | 1277 | case LO_SUM: |
9ae8ffe7 JL |
1278 | case MINUS: |
1279 | if (XEXP (src, 0) != dest && XEXP (src, 1) != dest) | |
ec907dd8 | 1280 | new_reg_base_value[regno] = 0; |
9ae8ffe7 | 1281 | break; |
61f0131c R |
1282 | case PLUS: |
1283 | /* If the value we add in the PLUS is also a valid base value, | |
1284 | this might be the actual base value, and the original value | |
1285 | an index. */ | |
1286 | { | |
1287 | rtx other = NULL_RTX; | |
1288 | ||
1289 | if (XEXP (src, 0) == dest) | |
1290 | other = XEXP (src, 1); | |
1291 | else if (XEXP (src, 1) == dest) | |
1292 | other = XEXP (src, 0); | |
1293 | ||
1294 | if (! other || find_base_value (other)) | |
1295 | new_reg_base_value[regno] = 0; | |
1296 | break; | |
1297 | } | |
9ae8ffe7 | 1298 | case AND: |
481683e1 | 1299 | if (XEXP (src, 0) != dest || !CONST_INT_P (XEXP (src, 1))) |
ec907dd8 | 1300 | new_reg_base_value[regno] = 0; |
9ae8ffe7 | 1301 | break; |
9ae8ffe7 | 1302 | default: |
ec907dd8 | 1303 | new_reg_base_value[regno] = 0; |
9ae8ffe7 JL |
1304 | break; |
1305 | } | |
1306 | /* If this is the first set of a register, record the value. */ | |
1307 | else if ((regno >= FIRST_PSEUDO_REGISTER || ! fixed_regs[regno]) | |
d7c028c0 | 1308 | && ! bitmap_bit_p (reg_seen, regno) && new_reg_base_value[regno] == 0) |
ec907dd8 | 1309 | new_reg_base_value[regno] = find_base_value (src); |
9ae8ffe7 | 1310 | |
d7c028c0 | 1311 | bitmap_set_bit (reg_seen, regno); |
9ae8ffe7 JL |
1312 | } |
1313 | ||
8fd0a474 AM |
1314 | /* Return REG_BASE_VALUE for REGNO. Selective scheduler uses this to avoid |
1315 | using hard registers with non-null REG_BASE_VALUE for renaming. */ | |
1316 | rtx | |
1317 | get_reg_base_value (unsigned int regno) | |
1318 | { | |
9771b263 | 1319 | return (*reg_base_value)[regno]; |
8fd0a474 AM |
1320 | } |
1321 | ||
bb1acb3e RH |
1322 | /* If a value is known for REGNO, return it. */ |
1323 | ||
c22cacf3 | 1324 | rtx |
bb1acb3e RH |
1325 | get_reg_known_value (unsigned int regno) |
1326 | { | |
1327 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1328 | { | |
1329 | regno -= FIRST_PSEUDO_REGISTER; | |
9771b263 DN |
1330 | if (regno < vec_safe_length (reg_known_value)) |
1331 | return (*reg_known_value)[regno]; | |
bb1acb3e RH |
1332 | } |
1333 | return NULL; | |
43fe47ca JW |
1334 | } |
1335 | ||
bb1acb3e RH |
1336 | /* Set it. */ |
1337 | ||
1338 | static void | |
1339 | set_reg_known_value (unsigned int regno, rtx val) | |
1340 | { | |
1341 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1342 | { | |
1343 | regno -= FIRST_PSEUDO_REGISTER; | |
9771b263 DN |
1344 | if (regno < vec_safe_length (reg_known_value)) |
1345 | (*reg_known_value)[regno] = val; | |
bb1acb3e RH |
1346 | } |
1347 | } | |
1348 | ||
1349 | /* Similarly for reg_known_equiv_p. */ | |
1350 | ||
1351 | bool | |
1352 | get_reg_known_equiv_p (unsigned int regno) | |
1353 | { | |
1354 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1355 | { | |
1356 | regno -= FIRST_PSEUDO_REGISTER; | |
9771b263 | 1357 | if (regno < vec_safe_length (reg_known_value)) |
d7c028c0 | 1358 | return bitmap_bit_p (reg_known_equiv_p, regno); |
bb1acb3e RH |
1359 | } |
1360 | return false; | |
1361 | } | |
1362 | ||
1363 | static void | |
1364 | set_reg_known_equiv_p (unsigned int regno, bool val) | |
1365 | { | |
1366 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1367 | { | |
1368 | regno -= FIRST_PSEUDO_REGISTER; | |
9771b263 | 1369 | if (regno < vec_safe_length (reg_known_value)) |
9ff3c7ca SB |
1370 | { |
1371 | if (val) | |
d7c028c0 | 1372 | bitmap_set_bit (reg_known_equiv_p, regno); |
9ff3c7ca | 1373 | else |
d7c028c0 | 1374 | bitmap_clear_bit (reg_known_equiv_p, regno); |
9ff3c7ca | 1375 | } |
bb1acb3e RH |
1376 | } |
1377 | } | |
1378 | ||
1379 | ||
db048faf MM |
1380 | /* Returns a canonical version of X, from the point of view alias |
1381 | analysis. (For example, if X is a MEM whose address is a register, | |
1382 | and the register has a known value (say a SYMBOL_REF), then a MEM | |
1383 | whose address is the SYMBOL_REF is returned.) */ | |
1384 | ||
1385 | rtx | |
4682ae04 | 1386 | canon_rtx (rtx x) |
9ae8ffe7 JL |
1387 | { |
1388 | /* Recursively look for equivalences. */ | |
f8cfc6aa | 1389 | if (REG_P (x) && REGNO (x) >= FIRST_PSEUDO_REGISTER) |
bb1acb3e RH |
1390 | { |
1391 | rtx t = get_reg_known_value (REGNO (x)); | |
1392 | if (t == x) | |
1393 | return x; | |
1394 | if (t) | |
1395 | return canon_rtx (t); | |
1396 | } | |
1397 | ||
1398 | if (GET_CODE (x) == PLUS) | |
9ae8ffe7 JL |
1399 | { |
1400 | rtx x0 = canon_rtx (XEXP (x, 0)); | |
1401 | rtx x1 = canon_rtx (XEXP (x, 1)); | |
1402 | ||
1403 | if (x0 != XEXP (x, 0) || x1 != XEXP (x, 1)) | |
1404 | { | |
481683e1 | 1405 | if (CONST_INT_P (x0)) |
0a81f074 | 1406 | return plus_constant (GET_MODE (x), x1, INTVAL (x0)); |
481683e1 | 1407 | else if (CONST_INT_P (x1)) |
0a81f074 | 1408 | return plus_constant (GET_MODE (x), x0, INTVAL (x1)); |
38a448ca | 1409 | return gen_rtx_PLUS (GET_MODE (x), x0, x1); |
9ae8ffe7 JL |
1410 | } |
1411 | } | |
d4b60170 | 1412 | |
9ae8ffe7 JL |
1413 | /* This gives us much better alias analysis when called from |
1414 | the loop optimizer. Note we want to leave the original | |
1415 | MEM alone, but need to return the canonicalized MEM with | |
1416 | all the flags with their original values. */ | |
3c0cb5de | 1417 | else if (MEM_P (x)) |
f1ec5147 | 1418 | x = replace_equiv_address_nv (x, canon_rtx (XEXP (x, 0))); |
d4b60170 | 1419 | |
9ae8ffe7 JL |
1420 | return x; |
1421 | } | |
1422 | ||
1423 | /* Return 1 if X and Y are identical-looking rtx's. | |
45183e03 | 1424 | Expect that X and Y has been already canonicalized. |
9ae8ffe7 JL |
1425 | |
1426 | We use the data in reg_known_value above to see if two registers with | |
1427 | different numbers are, in fact, equivalent. */ | |
1428 | ||
1429 | static int | |
ed7a4b4b | 1430 | rtx_equal_for_memref_p (const_rtx x, const_rtx y) |
9ae8ffe7 | 1431 | { |
b3694847 SS |
1432 | int i; |
1433 | int j; | |
1434 | enum rtx_code code; | |
1435 | const char *fmt; | |
9ae8ffe7 JL |
1436 | |
1437 | if (x == 0 && y == 0) | |
1438 | return 1; | |
1439 | if (x == 0 || y == 0) | |
1440 | return 0; | |
d4b60170 | 1441 | |
9ae8ffe7 JL |
1442 | if (x == y) |
1443 | return 1; | |
1444 | ||
1445 | code = GET_CODE (x); | |
1446 | /* Rtx's of different codes cannot be equal. */ | |
1447 | if (code != GET_CODE (y)) | |
1448 | return 0; | |
1449 | ||
1450 | /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. | |
1451 | (REG:SI x) and (REG:HI x) are NOT equivalent. */ | |
1452 | ||
1453 | if (GET_MODE (x) != GET_MODE (y)) | |
1454 | return 0; | |
1455 | ||
db048faf MM |
1456 | /* Some RTL can be compared without a recursive examination. */ |
1457 | switch (code) | |
1458 | { | |
1459 | case REG: | |
1460 | return REGNO (x) == REGNO (y); | |
1461 | ||
1462 | case LABEL_REF: | |
1463 | return XEXP (x, 0) == XEXP (y, 0); | |
ca7fd9cd | 1464 | |
db048faf MM |
1465 | case SYMBOL_REF: |
1466 | return XSTR (x, 0) == XSTR (y, 0); | |
1467 | ||
40e02b4a | 1468 | case VALUE: |
d8116890 | 1469 | CASE_CONST_UNIQUE: |
db048faf MM |
1470 | /* There's no need to compare the contents of CONST_DOUBLEs or |
1471 | CONST_INTs because pointer equality is a good enough | |
1472 | comparison for these nodes. */ | |
1473 | return 0; | |
1474 | ||
db048faf MM |
1475 | default: |
1476 | break; | |
1477 | } | |
9ae8ffe7 | 1478 | |
45183e03 JH |
1479 | /* canon_rtx knows how to handle plus. No need to canonicalize. */ |
1480 | if (code == PLUS) | |
9ae8ffe7 JL |
1481 | return ((rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 0)) |
1482 | && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 1))) | |
1483 | || (rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 1)) | |
1484 | && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 0)))); | |
45183e03 JH |
1485 | /* For commutative operations, the RTX match if the operand match in any |
1486 | order. Also handle the simple binary and unary cases without a loop. */ | |
ec8e098d | 1487 | if (COMMUTATIVE_P (x)) |
45183e03 JH |
1488 | { |
1489 | rtx xop0 = canon_rtx (XEXP (x, 0)); | |
1490 | rtx yop0 = canon_rtx (XEXP (y, 0)); | |
1491 | rtx yop1 = canon_rtx (XEXP (y, 1)); | |
1492 | ||
1493 | return ((rtx_equal_for_memref_p (xop0, yop0) | |
1494 | && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), yop1)) | |
1495 | || (rtx_equal_for_memref_p (xop0, yop1) | |
1496 | && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), yop0))); | |
1497 | } | |
ec8e098d | 1498 | else if (NON_COMMUTATIVE_P (x)) |
45183e03 JH |
1499 | { |
1500 | return (rtx_equal_for_memref_p (canon_rtx (XEXP (x, 0)), | |
4682ae04 | 1501 | canon_rtx (XEXP (y, 0))) |
45183e03 JH |
1502 | && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), |
1503 | canon_rtx (XEXP (y, 1)))); | |
1504 | } | |
ec8e098d | 1505 | else if (UNARY_P (x)) |
45183e03 | 1506 | return rtx_equal_for_memref_p (canon_rtx (XEXP (x, 0)), |
4682ae04 | 1507 | canon_rtx (XEXP (y, 0))); |
9ae8ffe7 JL |
1508 | |
1509 | /* Compare the elements. If any pair of corresponding elements | |
de12be17 JC |
1510 | fail to match, return 0 for the whole things. |
1511 | ||
1512 | Limit cases to types which actually appear in addresses. */ | |
9ae8ffe7 JL |
1513 | |
1514 | fmt = GET_RTX_FORMAT (code); | |
1515 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
1516 | { | |
1517 | switch (fmt[i]) | |
1518 | { | |
9ae8ffe7 JL |
1519 | case 'i': |
1520 | if (XINT (x, i) != XINT (y, i)) | |
1521 | return 0; | |
1522 | break; | |
1523 | ||
9ae8ffe7 JL |
1524 | case 'E': |
1525 | /* Two vectors must have the same length. */ | |
1526 | if (XVECLEN (x, i) != XVECLEN (y, i)) | |
1527 | return 0; | |
1528 | ||
1529 | /* And the corresponding elements must match. */ | |
1530 | for (j = 0; j < XVECLEN (x, i); j++) | |
45183e03 JH |
1531 | if (rtx_equal_for_memref_p (canon_rtx (XVECEXP (x, i, j)), |
1532 | canon_rtx (XVECEXP (y, i, j))) == 0) | |
9ae8ffe7 JL |
1533 | return 0; |
1534 | break; | |
1535 | ||
1536 | case 'e': | |
45183e03 JH |
1537 | if (rtx_equal_for_memref_p (canon_rtx (XEXP (x, i)), |
1538 | canon_rtx (XEXP (y, i))) == 0) | |
9ae8ffe7 JL |
1539 | return 0; |
1540 | break; | |
1541 | ||
3237ac18 AH |
1542 | /* This can happen for asm operands. */ |
1543 | case 's': | |
1544 | if (strcmp (XSTR (x, i), XSTR (y, i))) | |
1545 | return 0; | |
1546 | break; | |
1547 | ||
aee21ba9 JL |
1548 | /* This can happen for an asm which clobbers memory. */ |
1549 | case '0': | |
1550 | break; | |
1551 | ||
9ae8ffe7 JL |
1552 | /* It is believed that rtx's at this level will never |
1553 | contain anything but integers and other rtx's, | |
1554 | except for within LABEL_REFs and SYMBOL_REFs. */ | |
1555 | default: | |
298e6adc | 1556 | gcc_unreachable (); |
9ae8ffe7 JL |
1557 | } |
1558 | } | |
1559 | return 1; | |
1560 | } | |
1561 | ||
9e412ca3 | 1562 | static rtx |
4682ae04 | 1563 | find_base_term (rtx x) |
9ae8ffe7 | 1564 | { |
eab5c70a | 1565 | cselib_val *val; |
6f2ffb4b AO |
1566 | struct elt_loc_list *l, *f; |
1567 | rtx ret; | |
eab5c70a | 1568 | |
b949ea8b JW |
1569 | #if defined (FIND_BASE_TERM) |
1570 | /* Try machine-dependent ways to find the base term. */ | |
1571 | x = FIND_BASE_TERM (x); | |
1572 | #endif | |
1573 | ||
9ae8ffe7 JL |
1574 | switch (GET_CODE (x)) |
1575 | { | |
1576 | case REG: | |
1577 | return REG_BASE_VALUE (x); | |
1578 | ||
d288e53d | 1579 | case TRUNCATE: |
5932a4d4 | 1580 | /* As we do not know which address space the pointer is referring to, we can |
d4ebfa65 BE |
1581 | handle this only if the target does not support different pointer or |
1582 | address modes depending on the address space. */ | |
1583 | if (!target_default_pointer_address_modes_p ()) | |
1584 | return 0; | |
d288e53d | 1585 | if (GET_MODE_SIZE (GET_MODE (x)) < GET_MODE_SIZE (Pmode)) |
ca7fd9cd | 1586 | return 0; |
d288e53d | 1587 | /* Fall through. */ |
9ae8ffe7 | 1588 | case HIGH: |
6d849a2a JL |
1589 | case PRE_INC: |
1590 | case PRE_DEC: | |
1591 | case POST_INC: | |
1592 | case POST_DEC: | |
d288e53d DE |
1593 | case PRE_MODIFY: |
1594 | case POST_MODIFY: | |
6d849a2a JL |
1595 | return find_base_term (XEXP (x, 0)); |
1596 | ||
1abade85 RK |
1597 | case ZERO_EXTEND: |
1598 | case SIGN_EXTEND: /* Used for Alpha/NT pointers */ | |
5932a4d4 | 1599 | /* As we do not know which address space the pointer is referring to, we can |
d4ebfa65 BE |
1600 | handle this only if the target does not support different pointer or |
1601 | address modes depending on the address space. */ | |
1602 | if (!target_default_pointer_address_modes_p ()) | |
1603 | return 0; | |
1604 | ||
1abade85 RK |
1605 | { |
1606 | rtx temp = find_base_term (XEXP (x, 0)); | |
1607 | ||
5ae6cd0d | 1608 | if (temp != 0 && CONSTANT_P (temp)) |
1abade85 | 1609 | temp = convert_memory_address (Pmode, temp); |
1abade85 RK |
1610 | |
1611 | return temp; | |
1612 | } | |
1613 | ||
eab5c70a BS |
1614 | case VALUE: |
1615 | val = CSELIB_VAL_PTR (x); | |
6f2ffb4b AO |
1616 | ret = NULL_RTX; |
1617 | ||
40e02b4a | 1618 | if (!val) |
6f2ffb4b AO |
1619 | return ret; |
1620 | ||
0fe03ac3 JJ |
1621 | if (cselib_sp_based_value_p (val)) |
1622 | return static_reg_base_value[STACK_POINTER_REGNUM]; | |
1623 | ||
6f2ffb4b AO |
1624 | f = val->locs; |
1625 | /* Temporarily reset val->locs to avoid infinite recursion. */ | |
1626 | val->locs = NULL; | |
1627 | ||
1628 | for (l = f; l; l = l->next) | |
1629 | if (GET_CODE (l->loc) == VALUE | |
1630 | && CSELIB_VAL_PTR (l->loc)->locs | |
1631 | && !CSELIB_VAL_PTR (l->loc)->locs->next | |
1632 | && CSELIB_VAL_PTR (l->loc)->locs->loc == x) | |
1633 | continue; | |
1634 | else if ((ret = find_base_term (l->loc)) != 0) | |
1635 | break; | |
1636 | ||
1637 | val->locs = f; | |
1638 | return ret; | |
eab5c70a | 1639 | |
023f059b JJ |
1640 | case LO_SUM: |
1641 | /* The standard form is (lo_sum reg sym) so look only at the | |
1642 | second operand. */ | |
1643 | return find_base_term (XEXP (x, 1)); | |
1644 | ||
9ae8ffe7 JL |
1645 | case CONST: |
1646 | x = XEXP (x, 0); | |
1647 | if (GET_CODE (x) != PLUS && GET_CODE (x) != MINUS) | |
1648 | return 0; | |
938d968e | 1649 | /* Fall through. */ |
9ae8ffe7 JL |
1650 | case PLUS: |
1651 | case MINUS: | |
1652 | { | |
3c567fae JL |
1653 | rtx tmp1 = XEXP (x, 0); |
1654 | rtx tmp2 = XEXP (x, 1); | |
1655 | ||
f5143c46 | 1656 | /* This is a little bit tricky since we have to determine which of |
3c567fae JL |
1657 | the two operands represents the real base address. Otherwise this |
1658 | routine may return the index register instead of the base register. | |
1659 | ||
1660 | That may cause us to believe no aliasing was possible, when in | |
1661 | fact aliasing is possible. | |
1662 | ||
1663 | We use a few simple tests to guess the base register. Additional | |
1664 | tests can certainly be added. For example, if one of the operands | |
1665 | is a shift or multiply, then it must be the index register and the | |
1666 | other operand is the base register. */ | |
ca7fd9cd | 1667 | |
b949ea8b JW |
1668 | if (tmp1 == pic_offset_table_rtx && CONSTANT_P (tmp2)) |
1669 | return find_base_term (tmp2); | |
1670 | ||
3c567fae JL |
1671 | /* If either operand is known to be a pointer, then use it |
1672 | to determine the base term. */ | |
3502dc9c | 1673 | if (REG_P (tmp1) && REG_POINTER (tmp1)) |
7eba2d1f LM |
1674 | { |
1675 | rtx base = find_base_term (tmp1); | |
1676 | if (base) | |
1677 | return base; | |
1678 | } | |
3c567fae | 1679 | |
3502dc9c | 1680 | if (REG_P (tmp2) && REG_POINTER (tmp2)) |
7eba2d1f LM |
1681 | { |
1682 | rtx base = find_base_term (tmp2); | |
1683 | if (base) | |
1684 | return base; | |
1685 | } | |
3c567fae JL |
1686 | |
1687 | /* Neither operand was known to be a pointer. Go ahead and find the | |
1688 | base term for both operands. */ | |
1689 | tmp1 = find_base_term (tmp1); | |
1690 | tmp2 = find_base_term (tmp2); | |
1691 | ||
1692 | /* If either base term is named object or a special address | |
1693 | (like an argument or stack reference), then use it for the | |
1694 | base term. */ | |
9fc37b2b | 1695 | if (tmp1 != 0 && known_base_value_p (tmp1)) |
3c567fae JL |
1696 | return tmp1; |
1697 | ||
9fc37b2b | 1698 | if (tmp2 != 0 && known_base_value_p (tmp2)) |
3c567fae JL |
1699 | return tmp2; |
1700 | ||
1701 | /* We could not determine which of the two operands was the | |
1702 | base register and which was the index. So we can determine | |
1703 | nothing from the base alias check. */ | |
1704 | return 0; | |
9ae8ffe7 JL |
1705 | } |
1706 | ||
1707 | case AND: | |
481683e1 | 1708 | if (CONST_INT_P (XEXP (x, 1)) && INTVAL (XEXP (x, 1)) != 0) |
d288e53d | 1709 | return find_base_term (XEXP (x, 0)); |
9ae8ffe7 JL |
1710 | return 0; |
1711 | ||
1712 | case SYMBOL_REF: | |
1713 | case LABEL_REF: | |
1714 | return x; | |
1715 | ||
1716 | default: | |
1717 | return 0; | |
1718 | } | |
1719 | } | |
1720 | ||
9e412ca3 RS |
1721 | /* Return true if accesses to address X may alias accesses based |
1722 | on the stack pointer. */ | |
1723 | ||
1724 | bool | |
1725 | may_be_sp_based_p (rtx x) | |
1726 | { | |
1727 | rtx base = find_base_term (x); | |
1728 | return !base || base == static_reg_base_value[STACK_POINTER_REGNUM]; | |
1729 | } | |
1730 | ||
9ae8ffe7 JL |
1731 | /* Return 0 if the addresses X and Y are known to point to different |
1732 | objects, 1 if they might be pointers to the same object. */ | |
1733 | ||
1734 | static int | |
4682ae04 AJ |
1735 | base_alias_check (rtx x, rtx y, enum machine_mode x_mode, |
1736 | enum machine_mode y_mode) | |
9ae8ffe7 JL |
1737 | { |
1738 | rtx x_base = find_base_term (x); | |
1739 | rtx y_base = find_base_term (y); | |
1740 | ||
1c72c7f6 JC |
1741 | /* If the address itself has no known base see if a known equivalent |
1742 | value has one. If either address still has no known base, nothing | |
1743 | is known about aliasing. */ | |
1744 | if (x_base == 0) | |
1745 | { | |
1746 | rtx x_c; | |
d4b60170 | 1747 | |
1c72c7f6 JC |
1748 | if (! flag_expensive_optimizations || (x_c = canon_rtx (x)) == x) |
1749 | return 1; | |
d4b60170 | 1750 | |
1c72c7f6 JC |
1751 | x_base = find_base_term (x_c); |
1752 | if (x_base == 0) | |
1753 | return 1; | |
1754 | } | |
9ae8ffe7 | 1755 | |
1c72c7f6 JC |
1756 | if (y_base == 0) |
1757 | { | |
1758 | rtx y_c; | |
1759 | if (! flag_expensive_optimizations || (y_c = canon_rtx (y)) == y) | |
1760 | return 1; | |
d4b60170 | 1761 | |
1c72c7f6 JC |
1762 | y_base = find_base_term (y_c); |
1763 | if (y_base == 0) | |
1764 | return 1; | |
1765 | } | |
1766 | ||
1767 | /* If the base addresses are equal nothing is known about aliasing. */ | |
1768 | if (rtx_equal_p (x_base, y_base)) | |
9ae8ffe7 JL |
1769 | return 1; |
1770 | ||
435da628 UB |
1771 | /* The base addresses are different expressions. If they are not accessed |
1772 | via AND, there is no conflict. We can bring knowledge of object | |
1773 | alignment into play here. For example, on alpha, "char a, b;" can | |
1774 | alias one another, though "char a; long b;" cannot. AND addesses may | |
1775 | implicitly alias surrounding objects; i.e. unaligned access in DImode | |
1776 | via AND address can alias all surrounding object types except those | |
1777 | with aligment 8 or higher. */ | |
1778 | if (GET_CODE (x) == AND && GET_CODE (y) == AND) | |
1779 | return 1; | |
1780 | if (GET_CODE (x) == AND | |
481683e1 | 1781 | && (!CONST_INT_P (XEXP (x, 1)) |
435da628 UB |
1782 | || (int) GET_MODE_UNIT_SIZE (y_mode) < -INTVAL (XEXP (x, 1)))) |
1783 | return 1; | |
1784 | if (GET_CODE (y) == AND | |
481683e1 | 1785 | && (!CONST_INT_P (XEXP (y, 1)) |
435da628 UB |
1786 | || (int) GET_MODE_UNIT_SIZE (x_mode) < -INTVAL (XEXP (y, 1)))) |
1787 | return 1; | |
1788 | ||
1789 | /* Differing symbols not accessed via AND never alias. */ | |
9ae8ffe7 | 1790 | if (GET_CODE (x_base) != ADDRESS && GET_CODE (y_base) != ADDRESS) |
435da628 | 1791 | return 0; |
9ae8ffe7 | 1792 | |
9fc37b2b | 1793 | if (unique_base_value_p (x_base) || unique_base_value_p (y_base)) |
9ae8ffe7 JL |
1794 | return 0; |
1795 | ||
0d3c82d6 | 1796 | return 1; |
9ae8ffe7 JL |
1797 | } |
1798 | ||
a5628378 AO |
1799 | /* Callback for for_each_rtx, that returns 1 upon encountering a VALUE |
1800 | whose UID is greater than the int uid that D points to. */ | |
1801 | ||
1802 | static int | |
1803 | refs_newer_value_cb (rtx *x, void *d) | |
1804 | { | |
1805 | if (GET_CODE (*x) == VALUE && CSELIB_VAL_PTR (*x)->uid > *(int *)d) | |
1806 | return 1; | |
1807 | ||
1808 | return 0; | |
1809 | } | |
1810 | ||
1811 | /* Return TRUE if EXPR refers to a VALUE whose uid is greater than | |
1812 | that of V. */ | |
1813 | ||
1814 | static bool | |
1815 | refs_newer_value_p (rtx expr, rtx v) | |
1816 | { | |
1817 | int minuid = CSELIB_VAL_PTR (v)->uid; | |
1818 | ||
1819 | return for_each_rtx (&expr, refs_newer_value_cb, &minuid); | |
1820 | } | |
1821 | ||
eab5c70a BS |
1822 | /* Convert the address X into something we can use. This is done by returning |
1823 | it unchanged unless it is a value; in the latter case we call cselib to get | |
1824 | a more useful rtx. */ | |
3bdf5ad1 | 1825 | |
a13d4ebf | 1826 | rtx |
4682ae04 | 1827 | get_addr (rtx x) |
eab5c70a BS |
1828 | { |
1829 | cselib_val *v; | |
1830 | struct elt_loc_list *l; | |
1831 | ||
1832 | if (GET_CODE (x) != VALUE) | |
1833 | return x; | |
1834 | v = CSELIB_VAL_PTR (x); | |
40e02b4a JH |
1835 | if (v) |
1836 | { | |
0f68ba3e AO |
1837 | bool have_equivs = cselib_have_permanent_equivalences (); |
1838 | if (have_equivs) | |
1839 | v = canonical_cselib_val (v); | |
40e02b4a JH |
1840 | for (l = v->locs; l; l = l->next) |
1841 | if (CONSTANT_P (l->loc)) | |
1842 | return l->loc; | |
1843 | for (l = v->locs; l; l = l->next) | |
0f68ba3e AO |
1844 | if (!REG_P (l->loc) && !MEM_P (l->loc) |
1845 | /* Avoid infinite recursion when potentially dealing with | |
1846 | var-tracking artificial equivalences, by skipping the | |
1847 | equivalences themselves, and not choosing expressions | |
1848 | that refer to newer VALUEs. */ | |
1849 | && (!have_equivs | |
1850 | || (GET_CODE (l->loc) != VALUE | |
1851 | && !refs_newer_value_p (l->loc, x)))) | |
a5628378 | 1852 | return l->loc; |
0f68ba3e AO |
1853 | if (have_equivs) |
1854 | { | |
1855 | for (l = v->locs; l; l = l->next) | |
1856 | if (REG_P (l->loc) | |
1857 | || (GET_CODE (l->loc) != VALUE | |
1858 | && !refs_newer_value_p (l->loc, x))) | |
1859 | return l->loc; | |
1860 | /* Return the canonical value. */ | |
1861 | return v->val_rtx; | |
1862 | } | |
1863 | if (v->locs) | |
1864 | return v->locs->loc; | |
40e02b4a | 1865 | } |
eab5c70a BS |
1866 | return x; |
1867 | } | |
1868 | ||
39cec1ac MH |
1869 | /* Return the address of the (N_REFS + 1)th memory reference to ADDR |
1870 | where SIZE is the size in bytes of the memory reference. If ADDR | |
1871 | is not modified by the memory reference then ADDR is returned. */ | |
1872 | ||
04e2b4d3 | 1873 | static rtx |
4682ae04 | 1874 | addr_side_effect_eval (rtx addr, int size, int n_refs) |
39cec1ac MH |
1875 | { |
1876 | int offset = 0; | |
ca7fd9cd | 1877 | |
39cec1ac MH |
1878 | switch (GET_CODE (addr)) |
1879 | { | |
1880 | case PRE_INC: | |
1881 | offset = (n_refs + 1) * size; | |
1882 | break; | |
1883 | case PRE_DEC: | |
1884 | offset = -(n_refs + 1) * size; | |
1885 | break; | |
1886 | case POST_INC: | |
1887 | offset = n_refs * size; | |
1888 | break; | |
1889 | case POST_DEC: | |
1890 | offset = -n_refs * size; | |
1891 | break; | |
1892 | ||
1893 | default: | |
1894 | return addr; | |
1895 | } | |
ca7fd9cd | 1896 | |
39cec1ac | 1897 | if (offset) |
45183e03 | 1898 | addr = gen_rtx_PLUS (GET_MODE (addr), XEXP (addr, 0), |
c22cacf3 | 1899 | GEN_INT (offset)); |
39cec1ac MH |
1900 | else |
1901 | addr = XEXP (addr, 0); | |
45183e03 | 1902 | addr = canon_rtx (addr); |
39cec1ac MH |
1903 | |
1904 | return addr; | |
1905 | } | |
1906 | ||
f47e08d9 RG |
1907 | /* Return one if X and Y (memory addresses) reference the |
1908 | same location in memory or if the references overlap. | |
1909 | Return zero if they do not overlap, else return | |
1910 | minus one in which case they still might reference the same location. | |
1911 | ||
1912 | C is an offset accumulator. When | |
9ae8ffe7 JL |
1913 | C is nonzero, we are testing aliases between X and Y + C. |
1914 | XSIZE is the size in bytes of the X reference, | |
1915 | similarly YSIZE is the size in bytes for Y. | |
45183e03 | 1916 | Expect that canon_rtx has been already called for X and Y. |
9ae8ffe7 JL |
1917 | |
1918 | If XSIZE or YSIZE is zero, we do not know the amount of memory being | |
1919 | referenced (the reference was BLKmode), so make the most pessimistic | |
1920 | assumptions. | |
1921 | ||
c02f035f RH |
1922 | If XSIZE or YSIZE is negative, we may access memory outside the object |
1923 | being referenced as a side effect. This can happen when using AND to | |
1924 | align memory references, as is done on the Alpha. | |
1925 | ||
9ae8ffe7 | 1926 | Nice to notice that varying addresses cannot conflict with fp if no |
f47e08d9 RG |
1927 | local variables had their addresses taken, but that's too hard now. |
1928 | ||
1929 | ??? Contrary to the tree alias oracle this does not return | |
1930 | one for X + non-constant and Y + non-constant when X and Y are equal. | |
1931 | If that is fixed the TBAA hack for union type-punning can be removed. */ | |
9ae8ffe7 | 1932 | |
9ae8ffe7 | 1933 | static int |
4682ae04 | 1934 | memrefs_conflict_p (int xsize, rtx x, int ysize, rtx y, HOST_WIDE_INT c) |
9ae8ffe7 | 1935 | { |
eab5c70a | 1936 | if (GET_CODE (x) == VALUE) |
5312b066 JJ |
1937 | { |
1938 | if (REG_P (y)) | |
1939 | { | |
24f8d71e JJ |
1940 | struct elt_loc_list *l = NULL; |
1941 | if (CSELIB_VAL_PTR (x)) | |
a5628378 AO |
1942 | for (l = canonical_cselib_val (CSELIB_VAL_PTR (x))->locs; |
1943 | l; l = l->next) | |
24f8d71e JJ |
1944 | if (REG_P (l->loc) && rtx_equal_for_memref_p (l->loc, y)) |
1945 | break; | |
5312b066 JJ |
1946 | if (l) |
1947 | x = y; | |
1948 | else | |
1949 | x = get_addr (x); | |
1950 | } | |
1951 | /* Don't call get_addr if y is the same VALUE. */ | |
1952 | else if (x != y) | |
1953 | x = get_addr (x); | |
1954 | } | |
eab5c70a | 1955 | if (GET_CODE (y) == VALUE) |
5312b066 JJ |
1956 | { |
1957 | if (REG_P (x)) | |
1958 | { | |
24f8d71e JJ |
1959 | struct elt_loc_list *l = NULL; |
1960 | if (CSELIB_VAL_PTR (y)) | |
a5628378 AO |
1961 | for (l = canonical_cselib_val (CSELIB_VAL_PTR (y))->locs; |
1962 | l; l = l->next) | |
24f8d71e JJ |
1963 | if (REG_P (l->loc) && rtx_equal_for_memref_p (l->loc, x)) |
1964 | break; | |
5312b066 JJ |
1965 | if (l) |
1966 | y = x; | |
1967 | else | |
1968 | y = get_addr (y); | |
1969 | } | |
1970 | /* Don't call get_addr if x is the same VALUE. */ | |
1971 | else if (y != x) | |
1972 | y = get_addr (y); | |
1973 | } | |
9ae8ffe7 JL |
1974 | if (GET_CODE (x) == HIGH) |
1975 | x = XEXP (x, 0); | |
1976 | else if (GET_CODE (x) == LO_SUM) | |
1977 | x = XEXP (x, 1); | |
1978 | else | |
45183e03 | 1979 | x = addr_side_effect_eval (x, xsize, 0); |
9ae8ffe7 JL |
1980 | if (GET_CODE (y) == HIGH) |
1981 | y = XEXP (y, 0); | |
1982 | else if (GET_CODE (y) == LO_SUM) | |
1983 | y = XEXP (y, 1); | |
1984 | else | |
45183e03 | 1985 | y = addr_side_effect_eval (y, ysize, 0); |
9ae8ffe7 JL |
1986 | |
1987 | if (rtx_equal_for_memref_p (x, y)) | |
1988 | { | |
c02f035f | 1989 | if (xsize <= 0 || ysize <= 0) |
9ae8ffe7 JL |
1990 | return 1; |
1991 | if (c >= 0 && xsize > c) | |
1992 | return 1; | |
1993 | if (c < 0 && ysize+c > 0) | |
1994 | return 1; | |
1995 | return 0; | |
1996 | } | |
1997 | ||
6e73e666 JC |
1998 | /* This code used to check for conflicts involving stack references and |
1999 | globals but the base address alias code now handles these cases. */ | |
9ae8ffe7 JL |
2000 | |
2001 | if (GET_CODE (x) == PLUS) | |
2002 | { | |
2003 | /* The fact that X is canonicalized means that this | |
2004 | PLUS rtx is canonicalized. */ | |
2005 | rtx x0 = XEXP (x, 0); | |
2006 | rtx x1 = XEXP (x, 1); | |
2007 | ||
2008 | if (GET_CODE (y) == PLUS) | |
2009 | { | |
2010 | /* The fact that Y is canonicalized means that this | |
2011 | PLUS rtx is canonicalized. */ | |
2012 | rtx y0 = XEXP (y, 0); | |
2013 | rtx y1 = XEXP (y, 1); | |
2014 | ||
2015 | if (rtx_equal_for_memref_p (x1, y1)) | |
2016 | return memrefs_conflict_p (xsize, x0, ysize, y0, c); | |
2017 | if (rtx_equal_for_memref_p (x0, y0)) | |
2018 | return memrefs_conflict_p (xsize, x1, ysize, y1, c); | |
481683e1 | 2019 | if (CONST_INT_P (x1)) |
63be02db | 2020 | { |
481683e1 | 2021 | if (CONST_INT_P (y1)) |
63be02db JM |
2022 | return memrefs_conflict_p (xsize, x0, ysize, y0, |
2023 | c - INTVAL (x1) + INTVAL (y1)); | |
2024 | else | |
2025 | return memrefs_conflict_p (xsize, x0, ysize, y, | |
2026 | c - INTVAL (x1)); | |
2027 | } | |
481683e1 | 2028 | else if (CONST_INT_P (y1)) |
9ae8ffe7 JL |
2029 | return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1)); |
2030 | ||
f47e08d9 | 2031 | return -1; |
9ae8ffe7 | 2032 | } |
481683e1 | 2033 | else if (CONST_INT_P (x1)) |
9ae8ffe7 JL |
2034 | return memrefs_conflict_p (xsize, x0, ysize, y, c - INTVAL (x1)); |
2035 | } | |
2036 | else if (GET_CODE (y) == PLUS) | |
2037 | { | |
2038 | /* The fact that Y is canonicalized means that this | |
2039 | PLUS rtx is canonicalized. */ | |
2040 | rtx y0 = XEXP (y, 0); | |
2041 | rtx y1 = XEXP (y, 1); | |
2042 | ||
481683e1 | 2043 | if (CONST_INT_P (y1)) |
9ae8ffe7 JL |
2044 | return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1)); |
2045 | else | |
f47e08d9 | 2046 | return -1; |
9ae8ffe7 JL |
2047 | } |
2048 | ||
2049 | if (GET_CODE (x) == GET_CODE (y)) | |
2050 | switch (GET_CODE (x)) | |
2051 | { | |
2052 | case MULT: | |
2053 | { | |
2054 | /* Handle cases where we expect the second operands to be the | |
2055 | same, and check only whether the first operand would conflict | |
2056 | or not. */ | |
2057 | rtx x0, y0; | |
2058 | rtx x1 = canon_rtx (XEXP (x, 1)); | |
2059 | rtx y1 = canon_rtx (XEXP (y, 1)); | |
2060 | if (! rtx_equal_for_memref_p (x1, y1)) | |
f47e08d9 | 2061 | return -1; |
9ae8ffe7 JL |
2062 | x0 = canon_rtx (XEXP (x, 0)); |
2063 | y0 = canon_rtx (XEXP (y, 0)); | |
2064 | if (rtx_equal_for_memref_p (x0, y0)) | |
2065 | return (xsize == 0 || ysize == 0 | |
2066 | || (c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)); | |
2067 | ||
2068 | /* Can't properly adjust our sizes. */ | |
481683e1 | 2069 | if (!CONST_INT_P (x1)) |
f47e08d9 | 2070 | return -1; |
9ae8ffe7 JL |
2071 | xsize /= INTVAL (x1); |
2072 | ysize /= INTVAL (x1); | |
2073 | c /= INTVAL (x1); | |
2074 | return memrefs_conflict_p (xsize, x0, ysize, y0, c); | |
2075 | } | |
1d300e19 KG |
2076 | |
2077 | default: | |
2078 | break; | |
9ae8ffe7 JL |
2079 | } |
2080 | ||
a9bf4fe2 AO |
2081 | /* Deal with alignment ANDs by adjusting offset and size so as to |
2082 | cover the maximum range, without taking any previously known | |
5147bf6a AO |
2083 | alignment into account. Make a size negative after such an |
2084 | adjustments, so that, if we end up with e.g. two SYMBOL_REFs, we | |
2085 | assume a potential overlap, because they may end up in contiguous | |
2086 | memory locations and the stricter-alignment access may span over | |
2087 | part of both. */ | |
481683e1 | 2088 | if (GET_CODE (x) == AND && CONST_INT_P (XEXP (x, 1))) |
56ee9281 | 2089 | { |
a9bf4fe2 AO |
2090 | HOST_WIDE_INT sc = INTVAL (XEXP (x, 1)); |
2091 | unsigned HOST_WIDE_INT uc = sc; | |
5147bf6a | 2092 | if (sc < 0 && -uc == (uc & -uc)) |
a9bf4fe2 | 2093 | { |
5147bf6a AO |
2094 | if (xsize > 0) |
2095 | xsize = -xsize; | |
2096 | xsize += sc + 1; | |
fe8fb1c4 | 2097 | c -= sc + 1; |
a9bf4fe2 AO |
2098 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), |
2099 | ysize, y, c); | |
2100 | } | |
56ee9281 | 2101 | } |
481683e1 | 2102 | if (GET_CODE (y) == AND && CONST_INT_P (XEXP (y, 1))) |
c02f035f | 2103 | { |
a9bf4fe2 AO |
2104 | HOST_WIDE_INT sc = INTVAL (XEXP (y, 1)); |
2105 | unsigned HOST_WIDE_INT uc = sc; | |
5147bf6a | 2106 | if (sc < 0 && -uc == (uc & -uc)) |
a9bf4fe2 | 2107 | { |
5147bf6a AO |
2108 | if (ysize > 0) |
2109 | ysize = -ysize; | |
2110 | ysize += sc + 1; | |
fe8fb1c4 | 2111 | c += sc + 1; |
a9bf4fe2 AO |
2112 | return memrefs_conflict_p (xsize, x, |
2113 | ysize, canon_rtx (XEXP (y, 0)), c); | |
2114 | } | |
c02f035f | 2115 | } |
9ae8ffe7 JL |
2116 | |
2117 | if (CONSTANT_P (x)) | |
2118 | { | |
481683e1 | 2119 | if (CONST_INT_P (x) && CONST_INT_P (y)) |
9ae8ffe7 JL |
2120 | { |
2121 | c += (INTVAL (y) - INTVAL (x)); | |
c02f035f | 2122 | return (xsize <= 0 || ysize <= 0 |
9ae8ffe7 JL |
2123 | || (c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)); |
2124 | } | |
2125 | ||
2126 | if (GET_CODE (x) == CONST) | |
2127 | { | |
2128 | if (GET_CODE (y) == CONST) | |
2129 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), | |
2130 | ysize, canon_rtx (XEXP (y, 0)), c); | |
2131 | else | |
2132 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), | |
2133 | ysize, y, c); | |
2134 | } | |
2135 | if (GET_CODE (y) == CONST) | |
2136 | return memrefs_conflict_p (xsize, x, ysize, | |
2137 | canon_rtx (XEXP (y, 0)), c); | |
2138 | ||
2139 | if (CONSTANT_P (y)) | |
b949ea8b | 2140 | return (xsize <= 0 || ysize <= 0 |
c02f035f | 2141 | || (rtx_equal_for_memref_p (x, y) |
b949ea8b | 2142 | && ((c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)))); |
9ae8ffe7 | 2143 | |
f47e08d9 | 2144 | return -1; |
9ae8ffe7 | 2145 | } |
f47e08d9 RG |
2146 | |
2147 | return -1; | |
9ae8ffe7 JL |
2148 | } |
2149 | ||
2150 | /* Functions to compute memory dependencies. | |
2151 | ||
2152 | Since we process the insns in execution order, we can build tables | |
2153 | to keep track of what registers are fixed (and not aliased), what registers | |
2154 | are varying in known ways, and what registers are varying in unknown | |
2155 | ways. | |
2156 | ||
2157 | If both memory references are volatile, then there must always be a | |
2158 | dependence between the two references, since their order can not be | |
2159 | changed. A volatile and non-volatile reference can be interchanged | |
ca7fd9cd | 2160 | though. |
9ae8ffe7 | 2161 | |
53d9622b RS |
2162 | We also must allow AND addresses, because they may generate accesses |
2163 | outside the object being referenced. This is used to generate aligned | |
2164 | addresses from unaligned addresses, for instance, the alpha | |
dc1618bc | 2165 | storeqi_unaligned pattern. */ |
9ae8ffe7 JL |
2166 | |
2167 | /* Read dependence: X is read after read in MEM takes place. There can | |
96672a3e RH |
2168 | only be a dependence here if both reads are volatile, or if either is |
2169 | an explicit barrier. */ | |
9ae8ffe7 JL |
2170 | |
2171 | int | |
4f588890 | 2172 | read_dependence (const_rtx mem, const_rtx x) |
9ae8ffe7 | 2173 | { |
96672a3e RH |
2174 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) |
2175 | return true; | |
2176 | if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER | |
2177 | || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER) | |
2178 | return true; | |
2179 | return false; | |
9ae8ffe7 JL |
2180 | } |
2181 | ||
998d7deb RH |
2182 | /* Return true if we can determine that the fields referenced cannot |
2183 | overlap for any pair of objects. */ | |
2184 | ||
2185 | static bool | |
175a7536 | 2186 | nonoverlapping_component_refs_p (const_rtx rtlx, const_rtx rtly) |
998d7deb | 2187 | { |
175a7536 | 2188 | const_tree x = MEM_EXPR (rtlx), y = MEM_EXPR (rtly); |
4f588890 | 2189 | const_tree fieldx, fieldy, typex, typey, orig_y; |
998d7deb | 2190 | |
175a7536 MM |
2191 | if (!flag_strict_aliasing |
2192 | || !x || !y | |
2193 | || TREE_CODE (x) != COMPONENT_REF | |
2194 | || TREE_CODE (y) != COMPONENT_REF) | |
4c7af939 AB |
2195 | return false; |
2196 | ||
998d7deb RH |
2197 | do |
2198 | { | |
2199 | /* The comparison has to be done at a common type, since we don't | |
d6a7951f | 2200 | know how the inheritance hierarchy works. */ |
998d7deb RH |
2201 | orig_y = y; |
2202 | do | |
2203 | { | |
2204 | fieldx = TREE_OPERAND (x, 1); | |
c05a0766 | 2205 | typex = TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (fieldx)); |
998d7deb RH |
2206 | |
2207 | y = orig_y; | |
2208 | do | |
2209 | { | |
2210 | fieldy = TREE_OPERAND (y, 1); | |
c05a0766 | 2211 | typey = TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (fieldy)); |
998d7deb RH |
2212 | |
2213 | if (typex == typey) | |
2214 | goto found; | |
2215 | ||
2216 | y = TREE_OPERAND (y, 0); | |
2217 | } | |
2218 | while (y && TREE_CODE (y) == COMPONENT_REF); | |
2219 | ||
2220 | x = TREE_OPERAND (x, 0); | |
2221 | } | |
2222 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
998d7deb | 2223 | /* Never found a common type. */ |
c05a0766 | 2224 | return false; |
998d7deb RH |
2225 | |
2226 | found: | |
ee88e690 | 2227 | /* If we're left with accessing different fields of a structure, then no |
8bed6809 | 2228 | possible overlap, unless they are both bitfields. */ |
ee88e690 | 2229 | if (TREE_CODE (typex) == RECORD_TYPE && fieldx != fieldy) |
8bed6809 | 2230 | return !(DECL_BIT_FIELD (fieldx) && DECL_BIT_FIELD (fieldy)); |
998d7deb RH |
2231 | |
2232 | /* The comparison on the current field failed. If we're accessing | |
2233 | a very nested structure, look at the next outer level. */ | |
2234 | x = TREE_OPERAND (x, 0); | |
2235 | y = TREE_OPERAND (y, 0); | |
2236 | } | |
2237 | while (x && y | |
2238 | && TREE_CODE (x) == COMPONENT_REF | |
2239 | && TREE_CODE (y) == COMPONENT_REF); | |
ca7fd9cd | 2240 | |
998d7deb RH |
2241 | return false; |
2242 | } | |
2243 | ||
2244 | /* Look at the bottom of the COMPONENT_REF list for a DECL, and return it. */ | |
2245 | ||
2246 | static tree | |
4682ae04 | 2247 | decl_for_component_ref (tree x) |
998d7deb RH |
2248 | { |
2249 | do | |
2250 | { | |
2251 | x = TREE_OPERAND (x, 0); | |
2252 | } | |
2253 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
2254 | ||
2255 | return x && DECL_P (x) ? x : NULL_TREE; | |
2256 | } | |
2257 | ||
527210c4 RS |
2258 | /* Walk up the COMPONENT_REF list in X and adjust *OFFSET to compensate |
2259 | for the offset of the field reference. *KNOWN_P says whether the | |
2260 | offset is known. */ | |
998d7deb | 2261 | |
527210c4 RS |
2262 | static void |
2263 | adjust_offset_for_component_ref (tree x, bool *known_p, | |
2264 | HOST_WIDE_INT *offset) | |
998d7deb | 2265 | { |
527210c4 RS |
2266 | if (!*known_p) |
2267 | return; | |
ca7fd9cd | 2268 | do |
998d7deb | 2269 | { |
527210c4 | 2270 | tree xoffset = component_ref_field_offset (x); |
998d7deb RH |
2271 | tree field = TREE_OPERAND (x, 1); |
2272 | ||
527210c4 RS |
2273 | if (! host_integerp (xoffset, 1)) |
2274 | { | |
2275 | *known_p = false; | |
2276 | return; | |
2277 | } | |
2278 | *offset += (tree_low_cst (xoffset, 1) | |
998d7deb RH |
2279 | + (tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1) |
2280 | / BITS_PER_UNIT)); | |
2281 | ||
2282 | x = TREE_OPERAND (x, 0); | |
2283 | } | |
2284 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
998d7deb RH |
2285 | } |
2286 | ||
95bd1dd7 | 2287 | /* Return nonzero if we can determine the exprs corresponding to memrefs |
c6ea834c BM |
2288 | X and Y and they do not overlap. |
2289 | If LOOP_VARIANT is set, skip offset-based disambiguation */ | |
a4311dfe | 2290 | |
2e4e39f6 | 2291 | int |
c6ea834c | 2292 | nonoverlapping_memrefs_p (const_rtx x, const_rtx y, bool loop_invariant) |
a4311dfe | 2293 | { |
998d7deb | 2294 | tree exprx = MEM_EXPR (x), expry = MEM_EXPR (y); |
a4311dfe RK |
2295 | rtx rtlx, rtly; |
2296 | rtx basex, basey; | |
527210c4 RS |
2297 | bool moffsetx_known_p, moffsety_known_p; |
2298 | HOST_WIDE_INT moffsetx = 0, moffsety = 0; | |
a4311dfe RK |
2299 | HOST_WIDE_INT offsetx = 0, offsety = 0, sizex, sizey, tem; |
2300 | ||
998d7deb RH |
2301 | /* Unless both have exprs, we can't tell anything. */ |
2302 | if (exprx == 0 || expry == 0) | |
2303 | return 0; | |
2b22e382 RG |
2304 | |
2305 | /* For spill-slot accesses make sure we have valid offsets. */ | |
2306 | if ((exprx == get_spill_slot_decl (false) | |
527210c4 | 2307 | && ! MEM_OFFSET_KNOWN_P (x)) |
2b22e382 | 2308 | || (expry == get_spill_slot_decl (false) |
527210c4 | 2309 | && ! MEM_OFFSET_KNOWN_P (y))) |
2b22e382 | 2310 | return 0; |
c22cacf3 | 2311 | |
998d7deb | 2312 | /* If the field reference test failed, look at the DECLs involved. */ |
527210c4 RS |
2313 | moffsetx_known_p = MEM_OFFSET_KNOWN_P (x); |
2314 | if (moffsetx_known_p) | |
2315 | moffsetx = MEM_OFFSET (x); | |
998d7deb RH |
2316 | if (TREE_CODE (exprx) == COMPONENT_REF) |
2317 | { | |
2e0c984c RG |
2318 | tree t = decl_for_component_ref (exprx); |
2319 | if (! t) | |
2320 | return 0; | |
527210c4 | 2321 | adjust_offset_for_component_ref (exprx, &moffsetx_known_p, &moffsetx); |
2e0c984c | 2322 | exprx = t; |
998d7deb | 2323 | } |
c67a1cf6 | 2324 | |
527210c4 RS |
2325 | moffsety_known_p = MEM_OFFSET_KNOWN_P (y); |
2326 | if (moffsety_known_p) | |
2327 | moffsety = MEM_OFFSET (y); | |
998d7deb RH |
2328 | if (TREE_CODE (expry) == COMPONENT_REF) |
2329 | { | |
2e0c984c RG |
2330 | tree t = decl_for_component_ref (expry); |
2331 | if (! t) | |
2332 | return 0; | |
527210c4 | 2333 | adjust_offset_for_component_ref (expry, &moffsety_known_p, &moffsety); |
2e0c984c | 2334 | expry = t; |
998d7deb RH |
2335 | } |
2336 | ||
2337 | if (! DECL_P (exprx) || ! DECL_P (expry)) | |
a4311dfe RK |
2338 | return 0; |
2339 | ||
1307c758 RG |
2340 | /* With invalid code we can end up storing into the constant pool. |
2341 | Bail out to avoid ICEing when creating RTL for this. | |
2342 | See gfortran.dg/lto/20091028-2_0.f90. */ | |
2343 | if (TREE_CODE (exprx) == CONST_DECL | |
2344 | || TREE_CODE (expry) == CONST_DECL) | |
2345 | return 1; | |
2346 | ||
998d7deb RH |
2347 | rtlx = DECL_RTL (exprx); |
2348 | rtly = DECL_RTL (expry); | |
a4311dfe | 2349 | |
1edcd60b RK |
2350 | /* If either RTL is not a MEM, it must be a REG or CONCAT, meaning they |
2351 | can't overlap unless they are the same because we never reuse that part | |
2352 | of the stack frame used for locals for spilled pseudos. */ | |
3c0cb5de | 2353 | if ((!MEM_P (rtlx) || !MEM_P (rtly)) |
1edcd60b | 2354 | && ! rtx_equal_p (rtlx, rtly)) |
a4311dfe RK |
2355 | return 1; |
2356 | ||
5932a4d4 | 2357 | /* If we have MEMs referring to different address spaces (which can |
09e881c9 BE |
2358 | potentially overlap), we cannot easily tell from the addresses |
2359 | whether the references overlap. */ | |
2360 | if (MEM_P (rtlx) && MEM_P (rtly) | |
2361 | && MEM_ADDR_SPACE (rtlx) != MEM_ADDR_SPACE (rtly)) | |
2362 | return 0; | |
2363 | ||
a4311dfe RK |
2364 | /* Get the base and offsets of both decls. If either is a register, we |
2365 | know both are and are the same, so use that as the base. The only | |
2366 | we can avoid overlap is if we can deduce that they are nonoverlapping | |
2367 | pieces of that decl, which is very rare. */ | |
3c0cb5de | 2368 | basex = MEM_P (rtlx) ? XEXP (rtlx, 0) : rtlx; |
481683e1 | 2369 | if (GET_CODE (basex) == PLUS && CONST_INT_P (XEXP (basex, 1))) |
a4311dfe RK |
2370 | offsetx = INTVAL (XEXP (basex, 1)), basex = XEXP (basex, 0); |
2371 | ||
3c0cb5de | 2372 | basey = MEM_P (rtly) ? XEXP (rtly, 0) : rtly; |
481683e1 | 2373 | if (GET_CODE (basey) == PLUS && CONST_INT_P (XEXP (basey, 1))) |
a4311dfe RK |
2374 | offsety = INTVAL (XEXP (basey, 1)), basey = XEXP (basey, 0); |
2375 | ||
d746694a | 2376 | /* If the bases are different, we know they do not overlap if both |
ca7fd9cd | 2377 | are constants or if one is a constant and the other a pointer into the |
d746694a RK |
2378 | stack frame. Otherwise a different base means we can't tell if they |
2379 | overlap or not. */ | |
2380 | if (! rtx_equal_p (basex, basey)) | |
ca7fd9cd KH |
2381 | return ((CONSTANT_P (basex) && CONSTANT_P (basey)) |
2382 | || (CONSTANT_P (basex) && REG_P (basey) | |
2383 | && REGNO_PTR_FRAME_P (REGNO (basey))) | |
2384 | || (CONSTANT_P (basey) && REG_P (basex) | |
2385 | && REGNO_PTR_FRAME_P (REGNO (basex)))); | |
a4311dfe | 2386 | |
c6ea834c BM |
2387 | /* Offset based disambiguation not appropriate for loop invariant */ |
2388 | if (loop_invariant) | |
2389 | return 0; | |
2390 | ||
3c0cb5de | 2391 | sizex = (!MEM_P (rtlx) ? (int) GET_MODE_SIZE (GET_MODE (rtlx)) |
f5541398 | 2392 | : MEM_SIZE_KNOWN_P (rtlx) ? MEM_SIZE (rtlx) |
a4311dfe | 2393 | : -1); |
3c0cb5de | 2394 | sizey = (!MEM_P (rtly) ? (int) GET_MODE_SIZE (GET_MODE (rtly)) |
f5541398 RS |
2395 | : MEM_SIZE_KNOWN_P (rtly) ? MEM_SIZE (rtly) |
2396 | : -1); | |
a4311dfe | 2397 | |
0af5bc3e RK |
2398 | /* If we have an offset for either memref, it can update the values computed |
2399 | above. */ | |
527210c4 RS |
2400 | if (moffsetx_known_p) |
2401 | offsetx += moffsetx, sizex -= moffsetx; | |
2402 | if (moffsety_known_p) | |
2403 | offsety += moffsety, sizey -= moffsety; | |
a4311dfe | 2404 | |
0af5bc3e | 2405 | /* If a memref has both a size and an offset, we can use the smaller size. |
efc981bb | 2406 | We can't do this if the offset isn't known because we must view this |
0af5bc3e | 2407 | memref as being anywhere inside the DECL's MEM. */ |
527210c4 | 2408 | if (MEM_SIZE_KNOWN_P (x) && moffsetx_known_p) |
f5541398 | 2409 | sizex = MEM_SIZE (x); |
527210c4 | 2410 | if (MEM_SIZE_KNOWN_P (y) && moffsety_known_p) |
f5541398 | 2411 | sizey = MEM_SIZE (y); |
a4311dfe RK |
2412 | |
2413 | /* Put the values of the memref with the lower offset in X's values. */ | |
2414 | if (offsetx > offsety) | |
2415 | { | |
2416 | tem = offsetx, offsetx = offsety, offsety = tem; | |
2417 | tem = sizex, sizex = sizey, sizey = tem; | |
2418 | } | |
2419 | ||
2420 | /* If we don't know the size of the lower-offset value, we can't tell | |
2421 | if they conflict. Otherwise, we do the test. */ | |
a6f7c915 | 2422 | return sizex >= 0 && offsety >= offsetx + sizex; |
a4311dfe RK |
2423 | } |
2424 | ||
9362286d SB |
2425 | /* Helper for true_dependence and canon_true_dependence. |
2426 | Checks for true dependence: X is read after store in MEM takes place. | |
9ae8ffe7 | 2427 | |
9362286d SB |
2428 | If MEM_CANONICALIZED is FALSE, then X_ADDR and MEM_ADDR should be |
2429 | NULL_RTX, and the canonical addresses of MEM and X are both computed | |
2430 | here. If MEM_CANONICALIZED, then MEM must be already canonicalized. | |
2431 | ||
2432 | If X_ADDR is non-NULL, it is used in preference of XEXP (x, 0). | |
2433 | ||
2434 | Returns 1 if there is a true dependence, 0 otherwise. */ | |
2435 | ||
2436 | static int | |
2437 | true_dependence_1 (const_rtx mem, enum machine_mode mem_mode, rtx mem_addr, | |
53d9622b | 2438 | const_rtx x, rtx x_addr, bool mem_canonicalized) |
9ae8ffe7 | 2439 | { |
49982682 | 2440 | rtx base; |
f47e08d9 | 2441 | int ret; |
9ae8ffe7 | 2442 | |
9362286d SB |
2443 | gcc_checking_assert (mem_canonicalized ? (mem_addr != NULL_RTX) |
2444 | : (mem_addr == NULL_RTX && x_addr == NULL_RTX)); | |
2445 | ||
9ae8ffe7 JL |
2446 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) |
2447 | return 1; | |
2448 | ||
c4484b8f | 2449 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
ac3768f6 | 2450 | This is used in epilogue deallocation functions, and in cselib. */ |
c4484b8f RH |
2451 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) |
2452 | return 1; | |
2453 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
2454 | return 1; | |
9cd9e512 RH |
2455 | if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER |
2456 | || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER) | |
2457 | return 1; | |
c4484b8f | 2458 | |
389fdba0 RH |
2459 | /* Read-only memory is by definition never modified, and therefore can't |
2460 | conflict with anything. We don't expect to find read-only set on MEM, | |
41806d92 | 2461 | but stupid user tricks can produce them, so don't die. */ |
389fdba0 | 2462 | if (MEM_READONLY_P (x)) |
9ae8ffe7 JL |
2463 | return 0; |
2464 | ||
5932a4d4 | 2465 | /* If we have MEMs referring to different address spaces (which can |
09e881c9 BE |
2466 | potentially overlap), we cannot easily tell from the addresses |
2467 | whether the references overlap. */ | |
2468 | if (MEM_ADDR_SPACE (mem) != MEM_ADDR_SPACE (x)) | |
2469 | return 1; | |
2470 | ||
9362286d SB |
2471 | if (! mem_addr) |
2472 | { | |
2473 | mem_addr = XEXP (mem, 0); | |
2474 | if (mem_mode == VOIDmode) | |
2475 | mem_mode = GET_MODE (mem); | |
2476 | } | |
2477 | ||
2478 | if (! x_addr) | |
2147c71c | 2479 | { |
a522de15 SB |
2480 | x_addr = XEXP (x, 0); |
2481 | if (!((GET_CODE (x_addr) == VALUE | |
2482 | && GET_CODE (mem_addr) != VALUE | |
2483 | && reg_mentioned_p (x_addr, mem_addr)) | |
2484 | || (GET_CODE (x_addr) != VALUE | |
2485 | && GET_CODE (mem_addr) == VALUE | |
2486 | && reg_mentioned_p (mem_addr, x_addr)))) | |
2487 | { | |
2488 | x_addr = get_addr (x_addr); | |
2489 | if (! mem_canonicalized) | |
2490 | mem_addr = get_addr (mem_addr); | |
2491 | } | |
2147c71c | 2492 | } |
eab5c70a | 2493 | |
55efb413 JW |
2494 | base = find_base_term (x_addr); |
2495 | if (base && (GET_CODE (base) == LABEL_REF | |
2496 | || (GET_CODE (base) == SYMBOL_REF | |
2497 | && CONSTANT_POOL_ADDRESS_P (base)))) | |
2498 | return 0; | |
2499 | ||
eab5c70a | 2500 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), mem_mode)) |
1c72c7f6 JC |
2501 | return 0; |
2502 | ||
eab5c70a | 2503 | x_addr = canon_rtx (x_addr); |
9362286d SB |
2504 | if (!mem_canonicalized) |
2505 | mem_addr = canon_rtx (mem_addr); | |
6e73e666 | 2506 | |
f47e08d9 RG |
2507 | if ((ret = memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr, |
2508 | SIZE_FOR_MODE (x), x_addr, 0)) != -1) | |
2509 | return ret; | |
2510 | ||
a95b3cc7 | 2511 | if (mems_in_disjoint_alias_sets_p (x, mem)) |
f47e08d9 RG |
2512 | return 0; |
2513 | ||
c6ea834c | 2514 | if (nonoverlapping_memrefs_p (mem, x, false)) |
0211b6ab | 2515 | return 0; |
175a7536 MM |
2516 | |
2517 | if (nonoverlapping_component_refs_p (mem, x)) | |
2518 | return 0; | |
0211b6ab | 2519 | |
55b34b5f | 2520 | return rtx_refs_may_alias_p (x, mem, true); |
a13d4ebf AM |
2521 | } |
2522 | ||
9362286d SB |
2523 | /* True dependence: X is read after store in MEM takes place. */ |
2524 | ||
2525 | int | |
53d9622b | 2526 | true_dependence (const_rtx mem, enum machine_mode mem_mode, const_rtx x) |
9362286d SB |
2527 | { |
2528 | return true_dependence_1 (mem, mem_mode, NULL_RTX, | |
53d9622b | 2529 | x, NULL_RTX, /*mem_canonicalized=*/false); |
9362286d SB |
2530 | } |
2531 | ||
a13d4ebf | 2532 | /* Canonical true dependence: X is read after store in MEM takes place. |
ca7fd9cd KH |
2533 | Variant of true_dependence which assumes MEM has already been |
2534 | canonicalized (hence we no longer do that here). | |
9362286d SB |
2535 | The mem_addr argument has been added, since true_dependence_1 computed |
2536 | this value prior to canonicalizing. */ | |
a13d4ebf AM |
2537 | |
2538 | int | |
4f588890 | 2539 | canon_true_dependence (const_rtx mem, enum machine_mode mem_mode, rtx mem_addr, |
53d9622b | 2540 | const_rtx x, rtx x_addr) |
a13d4ebf | 2541 | { |
9362286d | 2542 | return true_dependence_1 (mem, mem_mode, mem_addr, |
53d9622b | 2543 | x, x_addr, /*mem_canonicalized=*/true); |
9ae8ffe7 JL |
2544 | } |
2545 | ||
da7d8304 | 2546 | /* Returns nonzero if a write to X might alias a previous read from |
389fdba0 | 2547 | (or, if WRITEP is nonzero, a write to) MEM. */ |
9ae8ffe7 | 2548 | |
2c72b78f | 2549 | static int |
4f588890 | 2550 | write_dependence_p (const_rtx mem, const_rtx x, int writep) |
9ae8ffe7 | 2551 | { |
6e73e666 | 2552 | rtx x_addr, mem_addr; |
49982682 | 2553 | rtx base; |
f47e08d9 | 2554 | int ret; |
6e73e666 | 2555 | |
9ae8ffe7 JL |
2556 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) |
2557 | return 1; | |
2558 | ||
c4484b8f RH |
2559 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
2560 | This is used in epilogue deallocation functions. */ | |
2561 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) | |
2562 | return 1; | |
2563 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
2564 | return 1; | |
9cd9e512 RH |
2565 | if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER |
2566 | || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER) | |
2567 | return 1; | |
c4484b8f | 2568 | |
389fdba0 RH |
2569 | /* A read from read-only memory can't conflict with read-write memory. */ |
2570 | if (!writep && MEM_READONLY_P (mem)) | |
2571 | return 0; | |
55efb413 | 2572 | |
5932a4d4 | 2573 | /* If we have MEMs referring to different address spaces (which can |
09e881c9 BE |
2574 | potentially overlap), we cannot easily tell from the addresses |
2575 | whether the references overlap. */ | |
2576 | if (MEM_ADDR_SPACE (mem) != MEM_ADDR_SPACE (x)) | |
2577 | return 1; | |
2578 | ||
2147c71c L |
2579 | x_addr = XEXP (x, 0); |
2580 | mem_addr = XEXP (mem, 0); | |
2581 | if (!((GET_CODE (x_addr) == VALUE | |
2582 | && GET_CODE (mem_addr) != VALUE | |
2583 | && reg_mentioned_p (x_addr, mem_addr)) | |
2584 | || (GET_CODE (x_addr) != VALUE | |
2585 | && GET_CODE (mem_addr) == VALUE | |
2586 | && reg_mentioned_p (mem_addr, x_addr)))) | |
2587 | { | |
2588 | x_addr = get_addr (x_addr); | |
2589 | mem_addr = get_addr (mem_addr); | |
2590 | } | |
55efb413 | 2591 | |
49982682 JW |
2592 | if (! writep) |
2593 | { | |
55efb413 | 2594 | base = find_base_term (mem_addr); |
49982682 JW |
2595 | if (base && (GET_CODE (base) == LABEL_REF |
2596 | || (GET_CODE (base) == SYMBOL_REF | |
2597 | && CONSTANT_POOL_ADDRESS_P (base)))) | |
2598 | return 0; | |
2599 | } | |
2600 | ||
eab5c70a BS |
2601 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), |
2602 | GET_MODE (mem))) | |
41472af8 MM |
2603 | return 0; |
2604 | ||
eab5c70a BS |
2605 | x_addr = canon_rtx (x_addr); |
2606 | mem_addr = canon_rtx (mem_addr); | |
6e73e666 | 2607 | |
f47e08d9 RG |
2608 | if ((ret = memrefs_conflict_p (SIZE_FOR_MODE (mem), mem_addr, |
2609 | SIZE_FOR_MODE (x), x_addr, 0)) != -1) | |
2610 | return ret; | |
2611 | ||
c6ea834c | 2612 | if (nonoverlapping_memrefs_p (x, mem, false)) |
c6df88cb MM |
2613 | return 0; |
2614 | ||
55b34b5f | 2615 | return rtx_refs_may_alias_p (x, mem, false); |
c6df88cb MM |
2616 | } |
2617 | ||
2618 | /* Anti dependence: X is written after read in MEM takes place. */ | |
2619 | ||
2620 | int | |
4f588890 | 2621 | anti_dependence (const_rtx mem, const_rtx x) |
c6df88cb | 2622 | { |
389fdba0 | 2623 | return write_dependence_p (mem, x, /*writep=*/0); |
9ae8ffe7 JL |
2624 | } |
2625 | ||
2626 | /* Output dependence: X is written after store in MEM takes place. */ | |
2627 | ||
2628 | int | |
4f588890 | 2629 | output_dependence (const_rtx mem, const_rtx x) |
9ae8ffe7 | 2630 | { |
389fdba0 | 2631 | return write_dependence_p (mem, x, /*writep=*/1); |
9ae8ffe7 | 2632 | } |
c14b9960 | 2633 | \f |
6e73e666 | 2634 | |
c6ea834c BM |
2635 | |
2636 | /* Check whether X may be aliased with MEM. Don't do offset-based | |
2637 | memory disambiguation & TBAA. */ | |
2638 | int | |
2639 | may_alias_p (const_rtx mem, const_rtx x) | |
2640 | { | |
2641 | rtx x_addr, mem_addr; | |
c6ea834c BM |
2642 | |
2643 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) | |
2644 | return 1; | |
2645 | ||
a95b3cc7 RG |
2646 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
2647 | This is used in epilogue deallocation functions. */ | |
2648 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) | |
2649 | return 1; | |
2650 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
c6ea834c | 2651 | return 1; |
c6ea834c BM |
2652 | if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER |
2653 | || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER) | |
2654 | return 1; | |
2655 | ||
2656 | /* Read-only memory is by definition never modified, and therefore can't | |
2657 | conflict with anything. We don't expect to find read-only set on MEM, | |
2658 | but stupid user tricks can produce them, so don't die. */ | |
2659 | if (MEM_READONLY_P (x)) | |
2660 | return 0; | |
2661 | ||
5932a4d4 | 2662 | /* If we have MEMs referring to different address spaces (which can |
c6ea834c BM |
2663 | potentially overlap), we cannot easily tell from the addresses |
2664 | whether the references overlap. */ | |
2665 | if (MEM_ADDR_SPACE (mem) != MEM_ADDR_SPACE (x)) | |
2666 | return 1; | |
2667 | ||
2668 | x_addr = XEXP (x, 0); | |
2669 | mem_addr = XEXP (mem, 0); | |
2670 | if (!((GET_CODE (x_addr) == VALUE | |
2671 | && GET_CODE (mem_addr) != VALUE | |
2672 | && reg_mentioned_p (x_addr, mem_addr)) | |
2673 | || (GET_CODE (x_addr) != VALUE | |
2674 | && GET_CODE (mem_addr) == VALUE | |
2675 | && reg_mentioned_p (mem_addr, x_addr)))) | |
2676 | { | |
2677 | x_addr = get_addr (x_addr); | |
2678 | mem_addr = get_addr (mem_addr); | |
2679 | } | |
2680 | ||
2681 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), GET_MODE (mem_addr))) | |
2682 | return 0; | |
2683 | ||
2684 | x_addr = canon_rtx (x_addr); | |
2685 | mem_addr = canon_rtx (mem_addr); | |
2686 | ||
2687 | if (nonoverlapping_memrefs_p (mem, x, true)) | |
2688 | return 0; | |
2689 | ||
c6ea834c BM |
2690 | /* TBAA not valid for loop_invarint */ |
2691 | return rtx_refs_may_alias_p (x, mem, false); | |
2692 | } | |
2693 | ||
6e73e666 | 2694 | void |
b5deb7b6 | 2695 | init_alias_target (void) |
6e73e666 | 2696 | { |
b3694847 | 2697 | int i; |
6e73e666 | 2698 | |
9fc37b2b RS |
2699 | if (!arg_base_value) |
2700 | arg_base_value = gen_rtx_ADDRESS (VOIDmode, 0); | |
2701 | ||
b5deb7b6 SL |
2702 | memset (static_reg_base_value, 0, sizeof static_reg_base_value); |
2703 | ||
6e73e666 JC |
2704 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) |
2705 | /* Check whether this register can hold an incoming pointer | |
2706 | argument. FUNCTION_ARG_REGNO_P tests outgoing register | |
ec5c56db | 2707 | numbers, so translate if necessary due to register windows. */ |
6e73e666 JC |
2708 | if (FUNCTION_ARG_REGNO_P (OUTGOING_REGNO (i)) |
2709 | && HARD_REGNO_MODE_OK (i, Pmode)) | |
9fc37b2b RS |
2710 | static_reg_base_value[i] = arg_base_value; |
2711 | ||
757e8ba2 JJ |
2712 | static_reg_base_value[STACK_POINTER_REGNUM] |
2713 | = unique_base_value (UNIQUE_BASE_VALUE_SP); | |
2714 | static_reg_base_value[ARG_POINTER_REGNUM] | |
2715 | = unique_base_value (UNIQUE_BASE_VALUE_ARGP); | |
2716 | static_reg_base_value[FRAME_POINTER_REGNUM] | |
2717 | = unique_base_value (UNIQUE_BASE_VALUE_FP); | |
e3339d0f | 2718 | #if !HARD_FRAME_POINTER_IS_FRAME_POINTER |
757e8ba2 JJ |
2719 | static_reg_base_value[HARD_FRAME_POINTER_REGNUM] |
2720 | = unique_base_value (UNIQUE_BASE_VALUE_HFP); | |
bf1660a6 JL |
2721 | #endif |
2722 | } | |
2723 | ||
7b52eede JH |
2724 | /* Set MEMORY_MODIFIED when X modifies DATA (that is assumed |
2725 | to be memory reference. */ | |
2726 | static bool memory_modified; | |
2727 | static void | |
aa317c97 | 2728 | memory_modified_1 (rtx x, const_rtx pat ATTRIBUTE_UNUSED, void *data) |
7b52eede | 2729 | { |
3c0cb5de | 2730 | if (MEM_P (x)) |
7b52eede | 2731 | { |
9678086d | 2732 | if (anti_dependence (x, (const_rtx)data) || output_dependence (x, (const_rtx)data)) |
7b52eede JH |
2733 | memory_modified = true; |
2734 | } | |
2735 | } | |
2736 | ||
2737 | ||
2738 | /* Return true when INSN possibly modify memory contents of MEM | |
454ff5cb | 2739 | (i.e. address can be modified). */ |
7b52eede | 2740 | bool |
9678086d | 2741 | memory_modified_in_insn_p (const_rtx mem, const_rtx insn) |
7b52eede JH |
2742 | { |
2743 | if (!INSN_P (insn)) | |
2744 | return false; | |
2745 | memory_modified = false; | |
aa317c97 | 2746 | note_stores (PATTERN (insn), memory_modified_1, CONST_CAST_RTX(mem)); |
7b52eede JH |
2747 | return memory_modified; |
2748 | } | |
2749 | ||
a7b159a4 AH |
2750 | /* Return TRUE if the destination of a set is rtx identical to |
2751 | ITEM. */ | |
2752 | static inline bool | |
2753 | set_dest_equal_p (const_rtx set, const_rtx item) | |
2754 | { | |
2755 | rtx dest = SET_DEST (set); | |
2756 | return rtx_equal_p (dest, item); | |
2757 | } | |
2758 | ||
2759 | /* Like memory_modified_in_insn_p, but return TRUE if INSN will | |
2760 | *DEFINITELY* modify the memory contents of MEM. */ | |
2761 | bool | |
2762 | memory_must_be_modified_in_insn_p (const_rtx mem, const_rtx insn) | |
2763 | { | |
2764 | if (!INSN_P (insn)) | |
2765 | return false; | |
2766 | insn = PATTERN (insn); | |
2767 | if (GET_CODE (insn) == SET) | |
2768 | return set_dest_equal_p (insn, mem); | |
2769 | else if (GET_CODE (insn) == PARALLEL) | |
2770 | { | |
2771 | int i; | |
2772 | for (i = 0; i < XVECLEN (insn, 0); i++) | |
2773 | { | |
2774 | rtx sub = XVECEXP (insn, 0, i); | |
2775 | if (GET_CODE (sub) == SET | |
2776 | && set_dest_equal_p (sub, mem)) | |
2777 | return true; | |
2778 | } | |
2779 | } | |
2780 | return false; | |
2781 | } | |
2782 | ||
c13e8210 MM |
2783 | /* Initialize the aliasing machinery. Initialize the REG_KNOWN_VALUE |
2784 | array. */ | |
2785 | ||
9ae8ffe7 | 2786 | void |
4682ae04 | 2787 | init_alias_analysis (void) |
9ae8ffe7 | 2788 | { |
c582d54a | 2789 | unsigned int maxreg = max_reg_num (); |
ea64ef27 | 2790 | int changed, pass; |
b3694847 SS |
2791 | int i; |
2792 | unsigned int ui; | |
9ff3c7ca | 2793 | rtx insn, val; |
131db6b8 SB |
2794 | int rpo_cnt; |
2795 | int *rpo; | |
9ae8ffe7 | 2796 | |
0d446150 JH |
2797 | timevar_push (TV_ALIAS_ANALYSIS); |
2798 | ||
92390dd1 | 2799 | vec_safe_grow_cleared (reg_known_value, maxreg - FIRST_PSEUDO_REGISTER); |
9ff3c7ca | 2800 | reg_known_equiv_p = sbitmap_alloc (maxreg - FIRST_PSEUDO_REGISTER); |
9ae8ffe7 | 2801 | |
08c79682 | 2802 | /* If we have memory allocated from the previous run, use it. */ |
c582d54a | 2803 | if (old_reg_base_value) |
08c79682 KH |
2804 | reg_base_value = old_reg_base_value; |
2805 | ||
2806 | if (reg_base_value) | |
9771b263 | 2807 | reg_base_value->truncate (0); |
08c79682 | 2808 | |
9771b263 | 2809 | vec_safe_grow_cleared (reg_base_value, maxreg); |
ac606739 | 2810 | |
5ed6ace5 | 2811 | new_reg_base_value = XNEWVEC (rtx, maxreg); |
d630245f | 2812 | reg_seen = sbitmap_alloc (maxreg); |
ec907dd8 JL |
2813 | |
2814 | /* The basic idea is that each pass through this loop will use the | |
2815 | "constant" information from the previous pass to propagate alias | |
2816 | information through another level of assignments. | |
2817 | ||
131db6b8 SB |
2818 | The propagation is done on the CFG in reverse post-order, to propagate |
2819 | things forward as far as possible in each iteration. | |
2820 | ||
ec907dd8 JL |
2821 | This could get expensive if the assignment chains are long. Maybe |
2822 | we should throttle the number of iterations, possibly based on | |
6e73e666 | 2823 | the optimization level or flag_expensive_optimizations. |
ec907dd8 JL |
2824 | |
2825 | We could propagate more information in the first pass by making use | |
6fb5fa3c | 2826 | of DF_REG_DEF_COUNT to determine immediately that the alias information |
ea64ef27 JL |
2827 | for a pseudo is "constant". |
2828 | ||
2829 | A program with an uninitialized variable can cause an infinite loop | |
2830 | here. Instead of doing a full dataflow analysis to detect such problems | |
2831 | we just cap the number of iterations for the loop. | |
2832 | ||
2833 | The state of the arrays for the set chain in question does not matter | |
2834 | since the program has undefined behavior. */ | |
6e73e666 | 2835 | |
131db6b8 SB |
2836 | rpo = XNEWVEC (int, n_basic_blocks); |
2837 | rpo_cnt = pre_and_rev_post_order_compute (NULL, rpo, false); | |
2838 | ||
ea64ef27 | 2839 | pass = 0; |
6e73e666 | 2840 | do |
ec907dd8 JL |
2841 | { |
2842 | /* Assume nothing will change this iteration of the loop. */ | |
2843 | changed = 0; | |
2844 | ||
ec907dd8 | 2845 | /* We want to assign the same IDs each iteration of this loop, so |
9fc37b2b RS |
2846 | start counting from one each iteration of the loop. */ |
2847 | unique_id = 1; | |
ec907dd8 | 2848 | |
f5143c46 | 2849 | /* We're at the start of the function each iteration through the |
ec907dd8 | 2850 | loop, so we're copying arguments. */ |
83bbd9b6 | 2851 | copying_arguments = true; |
9ae8ffe7 | 2852 | |
6e73e666 | 2853 | /* Wipe the potential alias information clean for this pass. */ |
c582d54a | 2854 | memset (new_reg_base_value, 0, maxreg * sizeof (rtx)); |
8072f69c | 2855 | |
6e73e666 | 2856 | /* Wipe the reg_seen array clean. */ |
f61e445a | 2857 | bitmap_clear (reg_seen); |
9ae8ffe7 | 2858 | |
6e73e666 JC |
2859 | /* Mark all hard registers which may contain an address. |
2860 | The stack, frame and argument pointers may contain an address. | |
2861 | An argument register which can hold a Pmode value may contain | |
2862 | an address even if it is not in BASE_REGS. | |
8072f69c | 2863 | |
6e73e666 JC |
2864 | The address expression is VOIDmode for an argument and |
2865 | Pmode for other registers. */ | |
2866 | ||
7f243674 JL |
2867 | memcpy (new_reg_base_value, static_reg_base_value, |
2868 | FIRST_PSEUDO_REGISTER * sizeof (rtx)); | |
6e73e666 | 2869 | |
ec907dd8 | 2870 | /* Walk the insns adding values to the new_reg_base_value array. */ |
131db6b8 | 2871 | for (i = 0; i < rpo_cnt; i++) |
9ae8ffe7 | 2872 | { |
131db6b8 SB |
2873 | basic_block bb = BASIC_BLOCK (rpo[i]); |
2874 | FOR_BB_INSNS (bb, insn) | |
ec907dd8 | 2875 | { |
131db6b8 SB |
2876 | if (NONDEBUG_INSN_P (insn)) |
2877 | { | |
2878 | rtx note, set; | |
efc9bd41 RK |
2879 | |
2880 | #if defined (HAVE_prologue) || defined (HAVE_epilogue) | |
131db6b8 SB |
2881 | /* The prologue/epilogue insns are not threaded onto the |
2882 | insn chain until after reload has completed. Thus, | |
2883 | there is no sense wasting time checking if INSN is in | |
2884 | the prologue/epilogue until after reload has completed. */ | |
2885 | if (reload_completed | |
2886 | && prologue_epilogue_contains (insn)) | |
2887 | continue; | |
efc9bd41 RK |
2888 | #endif |
2889 | ||
131db6b8 SB |
2890 | /* If this insn has a noalias note, process it, Otherwise, |
2891 | scan for sets. A simple set will have no side effects | |
2892 | which could change the base value of any other register. */ | |
6e73e666 | 2893 | |
131db6b8 SB |
2894 | if (GET_CODE (PATTERN (insn)) == SET |
2895 | && REG_NOTES (insn) != 0 | |
2896 | && find_reg_note (insn, REG_NOALIAS, NULL_RTX)) | |
2897 | record_set (SET_DEST (PATTERN (insn)), NULL_RTX, NULL); | |
2898 | else | |
2899 | note_stores (PATTERN (insn), record_set, NULL); | |
6e73e666 | 2900 | |
131db6b8 | 2901 | set = single_set (insn); |
6e73e666 | 2902 | |
131db6b8 SB |
2903 | if (set != 0 |
2904 | && REG_P (SET_DEST (set)) | |
2905 | && REGNO (SET_DEST (set)) >= FIRST_PSEUDO_REGISTER) | |
713f41f9 | 2906 | { |
131db6b8 SB |
2907 | unsigned int regno = REGNO (SET_DEST (set)); |
2908 | rtx src = SET_SRC (set); | |
2909 | rtx t; | |
2910 | ||
2911 | note = find_reg_equal_equiv_note (insn); | |
2912 | if (note && REG_NOTE_KIND (note) == REG_EQUAL | |
2913 | && DF_REG_DEF_COUNT (regno) != 1) | |
2914 | note = NULL_RTX; | |
2915 | ||
2916 | if (note != NULL_RTX | |
2917 | && GET_CODE (XEXP (note, 0)) != EXPR_LIST | |
2918 | && ! rtx_varies_p (XEXP (note, 0), 1) | |
2919 | && ! reg_overlap_mentioned_p (SET_DEST (set), | |
2920 | XEXP (note, 0))) | |
2921 | { | |
2922 | set_reg_known_value (regno, XEXP (note, 0)); | |
2923 | set_reg_known_equiv_p (regno, | |
2924 | REG_NOTE_KIND (note) == REG_EQUIV); | |
2925 | } | |
2926 | else if (DF_REG_DEF_COUNT (regno) == 1 | |
2927 | && GET_CODE (src) == PLUS | |
2928 | && REG_P (XEXP (src, 0)) | |
2929 | && (t = get_reg_known_value (REGNO (XEXP (src, 0)))) | |
2930 | && CONST_INT_P (XEXP (src, 1))) | |
2931 | { | |
2932 | t = plus_constant (GET_MODE (src), t, | |
2933 | INTVAL (XEXP (src, 1))); | |
2934 | set_reg_known_value (regno, t); | |
2935 | set_reg_known_equiv_p (regno, false); | |
2936 | } | |
2937 | else if (DF_REG_DEF_COUNT (regno) == 1 | |
2938 | && ! rtx_varies_p (src, 1)) | |
2939 | { | |
2940 | set_reg_known_value (regno, src); | |
2941 | set_reg_known_equiv_p (regno, false); | |
2942 | } | |
713f41f9 | 2943 | } |
6e73e666 | 2944 | } |
131db6b8 SB |
2945 | else if (NOTE_P (insn) |
2946 | && NOTE_KIND (insn) == NOTE_INSN_FUNCTION_BEG) | |
2947 | copying_arguments = false; | |
ec907dd8 | 2948 | } |
6e73e666 | 2949 | } |
ec907dd8 | 2950 | |
6e73e666 | 2951 | /* Now propagate values from new_reg_base_value to reg_base_value. */ |
62e5bf5d | 2952 | gcc_assert (maxreg == (unsigned int) max_reg_num ()); |
c22cacf3 | 2953 | |
c582d54a | 2954 | for (ui = 0; ui < maxreg; ui++) |
6e73e666 | 2955 | { |
e51712db | 2956 | if (new_reg_base_value[ui] |
9771b263 DN |
2957 | && new_reg_base_value[ui] != (*reg_base_value)[ui] |
2958 | && ! rtx_equal_p (new_reg_base_value[ui], (*reg_base_value)[ui])) | |
ec907dd8 | 2959 | { |
9771b263 | 2960 | (*reg_base_value)[ui] = new_reg_base_value[ui]; |
6e73e666 | 2961 | changed = 1; |
ec907dd8 | 2962 | } |
9ae8ffe7 | 2963 | } |
9ae8ffe7 | 2964 | } |
6e73e666 | 2965 | while (changed && ++pass < MAX_ALIAS_LOOP_PASSES); |
131db6b8 | 2966 | XDELETEVEC (rpo); |
9ae8ffe7 JL |
2967 | |
2968 | /* Fill in the remaining entries. */ | |
9771b263 | 2969 | FOR_EACH_VEC_ELT (*reg_known_value, i, val) |
9ff3c7ca SB |
2970 | { |
2971 | int regno = i + FIRST_PSEUDO_REGISTER; | |
2972 | if (! val) | |
2973 | set_reg_known_value (regno, regno_reg_rtx[regno]); | |
2974 | } | |
9ae8ffe7 | 2975 | |
e05e2395 MM |
2976 | /* Clean up. */ |
2977 | free (new_reg_base_value); | |
ec907dd8 | 2978 | new_reg_base_value = 0; |
d630245f | 2979 | sbitmap_free (reg_seen); |
9ae8ffe7 | 2980 | reg_seen = 0; |
0d446150 | 2981 | timevar_pop (TV_ALIAS_ANALYSIS); |
9ae8ffe7 JL |
2982 | } |
2983 | ||
61630b27 JJ |
2984 | /* Equate REG_BASE_VALUE (reg1) to REG_BASE_VALUE (reg2). |
2985 | Special API for var-tracking pass purposes. */ | |
2986 | ||
2987 | void | |
2988 | vt_equate_reg_base_value (const_rtx reg1, const_rtx reg2) | |
2989 | { | |
9771b263 | 2990 | (*reg_base_value)[REGNO (reg1)] = REG_BASE_VALUE (reg2); |
61630b27 JJ |
2991 | } |
2992 | ||
9ae8ffe7 | 2993 | void |
4682ae04 | 2994 | end_alias_analysis (void) |
9ae8ffe7 | 2995 | { |
c582d54a | 2996 | old_reg_base_value = reg_base_value; |
9771b263 | 2997 | vec_free (reg_known_value); |
9ff3c7ca | 2998 | sbitmap_free (reg_known_equiv_p); |
9ae8ffe7 | 2999 | } |
e2500fed GK |
3000 | |
3001 | #include "gt-alias.h" |