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9ae8ffe7 | 1 | /* Alias analysis for GNU C |
7adcbafe | 2 | Copyright (C) 1997-2022 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 | 23 | #include "coretypes.h" |
c7131fb2 | 24 | #include "backend.h" |
957060b5 AM |
25 | #include "target.h" |
26 | #include "rtl.h" | |
c7131fb2 AM |
27 | #include "tree.h" |
28 | #include "gimple.h" | |
c7131fb2 | 29 | #include "df.h" |
4d0cdd0c | 30 | #include "memmodel.h" |
957060b5 AM |
31 | #include "tm_p.h" |
32 | #include "gimple-ssa.h" | |
957060b5 | 33 | #include "emit-rtl.h" |
40e23961 | 34 | #include "alias.h" |
40e23961 | 35 | #include "fold-const.h" |
d8a2d370 | 36 | #include "varasm.h" |
eab5c70a | 37 | #include "cselib.h" |
d23c55c2 | 38 | #include "langhooks.h" |
60393bbc | 39 | #include "cfganal.h" |
403837b4 | 40 | #include "rtl-iter.h" |
54363f8a | 41 | #include "cgraph.h" |
e4b44fd7 | 42 | #include "ipa-utils.h" |
ea900239 DB |
43 | |
44 | /* The aliasing API provided here solves related but different problems: | |
45 | ||
c22cacf3 | 46 | Say there exists (in c) |
ea900239 DB |
47 | |
48 | struct X { | |
49 | struct Y y1; | |
50 | struct Z z2; | |
51 | } x1, *px1, *px2; | |
52 | ||
53 | struct Y y2, *py; | |
54 | struct Z z2, *pz; | |
55 | ||
56 | ||
308a3fe2 | 57 | py = &x1.y1; |
ea900239 DB |
58 | px2 = &x1; |
59 | ||
60 | Consider the four questions: | |
61 | ||
62 | Can a store to x1 interfere with px2->y1? | |
63 | Can a store to x1 interfere with px2->z2? | |
ea900239 DB |
64 | Can a store to x1 change the value pointed to by with py? |
65 | Can a store to x1 change the value pointed to by with pz? | |
66 | ||
67 | The answer to these questions can be yes, yes, yes, and maybe. | |
68 | ||
69 | The first two questions can be answered with a simple examination | |
70 | of the type system. If structure X contains a field of type Y then | |
073a8998 | 71 | a store through a pointer to an X can overwrite any field that is |
ea900239 DB |
72 | contained (recursively) in an X (unless we know that px1 != px2). |
73 | ||
308a3fe2 DS |
74 | The last two questions can be solved in the same way as the first |
75 | two questions but this is too conservative. The observation is | |
76 | that in some cases we can know which (if any) fields are addressed | |
77 | and if those addresses are used in bad ways. This analysis may be | |
78 | language specific. In C, arbitrary operations may be applied to | |
79 | pointers. However, there is some indication that this may be too | |
80 | conservative for some C++ types. | |
ea900239 DB |
81 | |
82 | The pass ipa-type-escape does this analysis for the types whose | |
c22cacf3 | 83 | instances do not escape across the compilation boundary. |
ea900239 DB |
84 | |
85 | Historically in GCC, these two problems were combined and a single | |
308a3fe2 | 86 | data structure that was used to represent the solution to these |
ea900239 | 87 | problems. We now have two similar but different data structures, |
308a3fe2 DS |
88 | The data structure to solve the last two questions is similar to |
89 | the first, but does not contain the fields whose address are never | |
90 | taken. For types that do escape the compilation unit, the data | |
91 | structures will have identical information. | |
ea900239 | 92 | */ |
3932261a MM |
93 | |
94 | /* The alias sets assigned to MEMs assist the back-end in determining | |
95 | which MEMs can alias which other MEMs. In general, two MEMs in | |
ac3d9668 RK |
96 | different alias sets cannot alias each other, with one important |
97 | exception. Consider something like: | |
3932261a | 98 | |
01d28c3f | 99 | struct S { int i; double d; }; |
3932261a MM |
100 | |
101 | a store to an `S' can alias something of either type `int' or type | |
102 | `double'. (However, a store to an `int' cannot alias a `double' | |
103 | and vice versa.) We indicate this via a tree structure that looks | |
104 | like: | |
c22cacf3 MS |
105 | struct S |
106 | / \ | |
3932261a | 107 | / \ |
c22cacf3 MS |
108 | |/_ _\| |
109 | int double | |
3932261a | 110 | |
ac3d9668 RK |
111 | (The arrows are directed and point downwards.) |
112 | In this situation we say the alias set for `struct S' is the | |
113 | `superset' and that those for `int' and `double' are `subsets'. | |
114 | ||
3bdf5ad1 RK |
115 | To see whether two alias sets can point to the same memory, we must |
116 | see if either alias set is a subset of the other. We need not trace | |
95bd1dd7 | 117 | past immediate descendants, however, since we propagate all |
3bdf5ad1 | 118 | grandchildren up one level. |
3932261a MM |
119 | |
120 | Alias set zero is implicitly a superset of all other alias sets. | |
121 | However, this is no actual entry for alias set zero. It is an | |
122 | error to attempt to explicitly construct a subset of zero. */ | |
123 | ||
e0702244 | 124 | struct alias_set_hash : int_hash <int, INT_MIN, INT_MIN + 1> {}; |
de144fb2 | 125 | |
02ced957 | 126 | struct GTY(()) alias_set_entry { |
3932261a | 127 | /* The alias set number, as stored in MEM_ALIAS_SET. */ |
4862826d | 128 | alias_set_type alias_set; |
3932261a | 129 | |
6e042ef4 JH |
130 | /* Nonzero if would have a child of zero: this effectively makes this |
131 | alias set the same as alias set zero. */ | |
132 | bool has_zero_child; | |
133 | /* Nonzero if alias set corresponds to pointer type itself (i.e. not to | |
134 | aggregate contaiing pointer. | |
135 | This is used for a special case where we need an universal pointer type | |
136 | compatible with all other pointer types. */ | |
137 | bool is_pointer; | |
138 | /* Nonzero if is_pointer or if one of childs have has_pointer set. */ | |
139 | bool has_pointer; | |
34e82342 RB |
140 | |
141 | /* The children of the alias set. These are not just the immediate | |
142 | children, but, in fact, all descendants. So, if we have: | |
143 | ||
144 | struct T { struct S s; float f; } | |
145 | ||
146 | continuing our example above, the children here will be all of | |
147 | `int', `double', `float', and `struct S'. */ | |
148 | hash_map<alias_set_hash, int> *children; | |
b604074c | 149 | }; |
9ae8ffe7 | 150 | |
ed7a4b4b | 151 | static int rtx_equal_for_memref_p (const_rtx, const_rtx); |
7bc980e1 | 152 | static void record_set (rtx, const_rtx, void *); |
ef4bddc2 RS |
153 | static int base_alias_check (rtx, rtx, rtx, rtx, machine_mode, |
154 | machine_mode); | |
4682ae04 | 155 | static rtx find_base_value (rtx); |
4f588890 | 156 | static int mems_in_disjoint_alias_sets_p (const_rtx, const_rtx); |
02ced957 | 157 | static alias_set_entry *get_alias_set_entry (alias_set_type); |
4682ae04 | 158 | static tree decl_for_component_ref (tree); |
bd280792 | 159 | static int write_dependence_p (const_rtx, |
ef4bddc2 | 160 | const_rtx, machine_mode, rtx, |
bd280792 | 161 | bool, bool, bool); |
6a2a3862 RS |
162 | static int compare_base_symbol_refs (const_rtx, const_rtx, |
163 | HOST_WIDE_INT * = NULL); | |
4682ae04 | 164 | |
aa317c97 | 165 | static void memory_modified_1 (rtx, const_rtx, void *); |
9ae8ffe7 | 166 | |
3ecf9d13 JH |
167 | /* Query statistics for the different low-level disambiguators. |
168 | A high-level query may trigger multiple of them. */ | |
169 | ||
170 | static struct { | |
171 | unsigned long long num_alias_zero; | |
172 | unsigned long long num_same_alias_set; | |
173 | unsigned long long num_same_objects; | |
174 | unsigned long long num_volatile; | |
175 | unsigned long long num_dag; | |
6e042ef4 | 176 | unsigned long long num_universal; |
3ecf9d13 JH |
177 | unsigned long long num_disambiguated; |
178 | } alias_stats; | |
179 | ||
180 | ||
9ae8ffe7 JL |
181 | /* Set up all info needed to perform alias analysis on memory references. */ |
182 | ||
d4b60170 | 183 | /* Returns the size in bytes of the mode of X. */ |
9ae8ffe7 JL |
184 | #define SIZE_FOR_MODE(X) (GET_MODE_SIZE (GET_MODE (X))) |
185 | ||
ea64ef27 | 186 | /* Cap the number of passes we make over the insns propagating alias |
131db6b8 SB |
187 | information through set chains. |
188 | ??? 10 is a completely arbitrary choice. This should be based on the | |
189 | maximum loop depth in the CFG, but we do not have this information | |
190 | available (even if current_loops _is_ available). */ | |
ea64ef27 | 191 | #define MAX_ALIAS_LOOP_PASSES 10 |
ca7fd9cd | 192 | |
9ae8ffe7 JL |
193 | /* reg_base_value[N] gives an address to which register N is related. |
194 | If all sets after the first add or subtract to the current value | |
195 | or otherwise modify it so it does not point to a different top level | |
196 | object, reg_base_value[N] is equal to the address part of the source | |
2a2c8203 JC |
197 | of the first set. |
198 | ||
199 | A base address can be an ADDRESS, SYMBOL_REF, or LABEL_REF. ADDRESS | |
9fc37b2b | 200 | expressions represent three types of base: |
b3b5ad95 | 201 | |
9fc37b2b RS |
202 | 1. incoming arguments. There is just one ADDRESS to represent all |
203 | arguments, since we do not know at this level whether accesses | |
204 | based on different arguments can alias. The ADDRESS has id 0. | |
b3b5ad95 | 205 | |
9fc37b2b RS |
206 | 2. stack_pointer_rtx, frame_pointer_rtx, hard_frame_pointer_rtx |
207 | (if distinct from frame_pointer_rtx) and arg_pointer_rtx. | |
208 | Each of these rtxes has a separate ADDRESS associated with it, | |
209 | each with a negative id. | |
210 | ||
211 | GCC is (and is required to be) precise in which register it | |
212 | chooses to access a particular region of stack. We can therefore | |
213 | assume that accesses based on one of these rtxes do not alias | |
214 | accesses based on another of these rtxes. | |
215 | ||
216 | 3. bases that are derived from malloc()ed memory (REG_NOALIAS). | |
217 | Each such piece of memory has a separate ADDRESS associated | |
218 | with it, each with an id greater than 0. | |
219 | ||
220 | Accesses based on one ADDRESS do not alias accesses based on other | |
221 | ADDRESSes. Accesses based on ADDRESSes in groups (2) and (3) do not | |
222 | alias globals either; the ADDRESSes have Pmode to indicate this. | |
223 | The ADDRESS in group (1) _may_ alias globals; it has VOIDmode to | |
224 | indicate this. */ | |
2a2c8203 | 225 | |
9771b263 | 226 | static GTY(()) vec<rtx, va_gc> *reg_base_value; |
ac606739 | 227 | static rtx *new_reg_base_value; |
c582d54a | 228 | |
9fc37b2b RS |
229 | /* The single VOIDmode ADDRESS that represents all argument bases. |
230 | It has id 0. */ | |
231 | static GTY(()) rtx arg_base_value; | |
232 | ||
233 | /* Used to allocate unique ids to each REG_NOALIAS ADDRESS. */ | |
234 | static int unique_id; | |
235 | ||
c582d54a JH |
236 | /* We preserve the copy of old array around to avoid amount of garbage |
237 | produced. About 8% of garbage produced were attributed to this | |
238 | array. */ | |
9771b263 | 239 | static GTY((deletable)) vec<rtx, va_gc> *old_reg_base_value; |
d4b60170 | 240 | |
9e412ca3 RS |
241 | /* Values of XINT (address, 0) of Pmode ADDRESS rtxes for special |
242 | registers. */ | |
243 | #define UNIQUE_BASE_VALUE_SP -1 | |
244 | #define UNIQUE_BASE_VALUE_ARGP -2 | |
245 | #define UNIQUE_BASE_VALUE_FP -3 | |
246 | #define UNIQUE_BASE_VALUE_HFP -4 | |
247 | ||
7bf84454 RS |
248 | #define static_reg_base_value \ |
249 | (this_target_rtl->x_static_reg_base_value) | |
bf1660a6 | 250 | |
9771b263 DN |
251 | #define REG_BASE_VALUE(X) \ |
252 | (REGNO (X) < vec_safe_length (reg_base_value) \ | |
253 | ? (*reg_base_value)[REGNO (X)] : 0) | |
9ae8ffe7 | 254 | |
c13e8210 | 255 | /* Vector indexed by N giving the initial (unchanging) value known for |
9ff3c7ca | 256 | pseudo-register N. This vector is initialized in init_alias_analysis, |
bb1acb3e | 257 | and does not change until end_alias_analysis is called. */ |
9771b263 | 258 | static GTY(()) vec<rtx, va_gc> *reg_known_value; |
9ae8ffe7 JL |
259 | |
260 | /* Vector recording for each reg_known_value whether it is due to a | |
261 | REG_EQUIV note. Future passes (viz., reload) may replace the | |
262 | pseudo with the equivalent expression and so we account for the | |
ac3d9668 RK |
263 | dependences that would be introduced if that happens. |
264 | ||
265 | The REG_EQUIV notes created in assign_parms may mention the arg | |
266 | pointer, and there are explicit insns in the RTL that modify the | |
267 | arg pointer. Thus we must ensure that such insns don't get | |
268 | scheduled across each other because that would invalidate the | |
269 | REG_EQUIV notes. One could argue that the REG_EQUIV notes are | |
270 | wrong, but solving the problem in the scheduler will likely give | |
271 | better code, so we do it here. */ | |
9ff3c7ca | 272 | static sbitmap reg_known_equiv_p; |
9ae8ffe7 | 273 | |
2a2c8203 JC |
274 | /* True when scanning insns from the start of the rtl to the |
275 | NOTE_INSN_FUNCTION_BEG note. */ | |
83bbd9b6 | 276 | static bool copying_arguments; |
9ae8ffe7 | 277 | |
1a5640b4 | 278 | |
3932261a | 279 | /* The splay-tree used to store the various alias set entries. */ |
02ced957 | 280 | static GTY (()) vec<alias_set_entry *, va_gc> *alias_sets; |
ac3d9668 | 281 | \f |
55b34b5f RG |
282 | /* Build a decomposed reference object for querying the alias-oracle |
283 | from the MEM rtx and store it in *REF. | |
284 | Returns false if MEM is not suitable for the alias-oracle. */ | |
285 | ||
286 | static bool | |
287 | ao_ref_from_mem (ao_ref *ref, const_rtx mem) | |
288 | { | |
289 | tree expr = MEM_EXPR (mem); | |
290 | tree base; | |
291 | ||
292 | if (!expr) | |
293 | return false; | |
294 | ||
295 | ao_ref_init (ref, expr); | |
296 | ||
297 | /* Get the base of the reference and see if we have to reject or | |
298 | adjust it. */ | |
299 | base = ao_ref_base (ref); | |
300 | if (base == NULL_TREE) | |
301 | return false; | |
302 | ||
ef7a9fb8 RB |
303 | /* The tree oracle doesn't like bases that are neither decls |
304 | nor indirect references of SSA names. */ | |
305 | if (!(DECL_P (base) | |
306 | || (TREE_CODE (base) == MEM_REF | |
307 | && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME) | |
308 | || (TREE_CODE (base) == TARGET_MEM_REF | |
309 | && TREE_CODE (TMR_BASE (base)) == SSA_NAME))) | |
d15adbeb | 310 | return false; |
55b34b5f | 311 | |
55b34b5f RG |
312 | ref->ref_alias_set = MEM_ALIAS_SET (mem); |
313 | ||
f68396a1 RG |
314 | /* If MEM_OFFSET or MEM_SIZE are unknown what we got from MEM_EXPR |
315 | is conservative, so trust it. */ | |
527210c4 | 316 | if (!MEM_OFFSET_KNOWN_P (mem) |
f5541398 | 317 | || !MEM_SIZE_KNOWN_P (mem)) |
f68396a1 | 318 | return true; |
366f945f | 319 | |
e8024441 RB |
320 | /* If MEM_OFFSET/MEM_SIZE get us outside of ref->offset/ref->max_size |
321 | drop ref->ref. */ | |
d05d7551 | 322 | if (maybe_lt (MEM_OFFSET (mem), 0) |
b9c25734 RS |
323 | || (ref->max_size_known_p () |
324 | && maybe_gt ((MEM_OFFSET (mem) + MEM_SIZE (mem)) * BITS_PER_UNIT, | |
325 | ref->max_size))) | |
e8024441 | 326 | ref->ref = NULL_TREE; |
b0e96404 | 327 | |
e8024441 RB |
328 | /* Refine size and offset we got from analyzing MEM_EXPR by using |
329 | MEM_SIZE and MEM_OFFSET. */ | |
f68396a1 | 330 | |
527210c4 | 331 | ref->offset += MEM_OFFSET (mem) * BITS_PER_UNIT; |
f5541398 | 332 | ref->size = MEM_SIZE (mem) * BITS_PER_UNIT; |
b0e96404 RG |
333 | |
334 | /* The MEM may extend into adjacent fields, so adjust max_size if | |
335 | necessary. */ | |
b9c25734 RS |
336 | if (ref->max_size_known_p ()) |
337 | ref->max_size = upper_bound (ref->max_size, ref->size); | |
b0e96404 | 338 | |
b9c25734 | 339 | /* If MEM_OFFSET and MEM_SIZE might get us outside of the base object of |
b0e96404 RG |
340 | the MEM_EXPR punt. This happens for STRICT_ALIGNMENT targets a lot. */ |
341 | if (MEM_EXPR (mem) != get_spill_slot_decl (false) | |
b9c25734 | 342 | && (maybe_lt (ref->offset, 0) |
b0e96404 | 343 | || (DECL_P (ref->base) |
807e902e | 344 | && (DECL_SIZE (ref->base) == NULL_TREE |
b9c25734 RS |
345 | || !poly_int_tree_p (DECL_SIZE (ref->base)) |
346 | || maybe_lt (wi::to_poly_offset (DECL_SIZE (ref->base)), | |
347 | ref->offset + ref->size))))) | |
b0e96404 | 348 | return false; |
55b34b5f RG |
349 | |
350 | return true; | |
351 | } | |
352 | ||
353 | /* Query the alias-oracle on whether the two memory rtx X and MEM may | |
354 | alias. If TBAA_P is set also apply TBAA. Returns true if the | |
355 | two rtxen may alias, false otherwise. */ | |
356 | ||
357 | static bool | |
358 | rtx_refs_may_alias_p (const_rtx x, const_rtx mem, bool tbaa_p) | |
359 | { | |
360 | ao_ref ref1, ref2; | |
361 | ||
362 | if (!ao_ref_from_mem (&ref1, x) | |
363 | || !ao_ref_from_mem (&ref2, mem)) | |
364 | return true; | |
365 | ||
55e3bc4c RG |
366 | return refs_may_alias_p_1 (&ref1, &ref2, |
367 | tbaa_p | |
368 | && MEM_ALIAS_SET (x) != 0 | |
369 | && MEM_ALIAS_SET (mem) != 0); | |
55b34b5f RG |
370 | } |
371 | ||
3d6fd7ce RB |
372 | /* Return true if the ref EARLIER behaves the same as LATER with respect |
373 | to TBAA for every memory reference that might follow LATER. */ | |
374 | ||
375 | bool | |
376 | refs_same_for_tbaa_p (tree earlier, tree later) | |
377 | { | |
378 | ao_ref earlier_ref, later_ref; | |
379 | ao_ref_init (&earlier_ref, earlier); | |
380 | ao_ref_init (&later_ref, later); | |
381 | alias_set_type earlier_set = ao_ref_alias_set (&earlier_ref); | |
382 | alias_set_type later_set = ao_ref_alias_set (&later_ref); | |
383 | if (!(earlier_set == later_set | |
384 | || alias_set_subset_of (later_set, earlier_set))) | |
385 | return false; | |
386 | alias_set_type later_base_set = ao_ref_base_alias_set (&later_ref); | |
387 | alias_set_type earlier_base_set = ao_ref_base_alias_set (&earlier_ref); | |
388 | return (earlier_base_set == later_base_set | |
389 | || alias_set_subset_of (later_base_set, earlier_base_set)); | |
390 | } | |
391 | ||
64ce76d9 RE |
392 | /* Similar to refs_same_for_tbaa_p() but for use on MEM rtxs. */ |
393 | bool | |
394 | mems_same_for_tbaa_p (rtx earlier, rtx later) | |
395 | { | |
396 | gcc_assert (MEM_P (earlier)); | |
397 | gcc_assert (MEM_P (later)); | |
398 | ||
399 | return ((MEM_ALIAS_SET (earlier) == MEM_ALIAS_SET (later) | |
400 | || alias_set_subset_of (MEM_ALIAS_SET (later), | |
401 | MEM_ALIAS_SET (earlier))) | |
402 | && (!MEM_EXPR (earlier) | |
403 | || refs_same_for_tbaa_p (MEM_EXPR (earlier), MEM_EXPR (later)))); | |
404 | } | |
405 | ||
3932261a MM |
406 | /* Returns a pointer to the alias set entry for ALIAS_SET, if there is |
407 | such an entry, or NULL otherwise. */ | |
408 | ||
02ced957 | 409 | static inline alias_set_entry * |
4862826d | 410 | get_alias_set_entry (alias_set_type alias_set) |
3932261a | 411 | { |
9771b263 | 412 | return (*alias_sets)[alias_set]; |
3932261a MM |
413 | } |
414 | ||
ac3d9668 RK |
415 | /* Returns nonzero if the alias sets for MEM1 and MEM2 are such that |
416 | the two MEMs cannot alias each other. */ | |
3932261a | 417 | |
9ddb66ca | 418 | static inline int |
4f588890 | 419 | mems_in_disjoint_alias_sets_p (const_rtx mem1, const_rtx mem2) |
3932261a | 420 | { |
598f8eca RB |
421 | return (flag_strict_aliasing |
422 | && ! alias_sets_conflict_p (MEM_ALIAS_SET (mem1), | |
423 | MEM_ALIAS_SET (mem2))); | |
1da68f56 | 424 | } |
3932261a | 425 | |
c58936b6 DB |
426 | /* Return true if the first alias set is a subset of the second. */ |
427 | ||
428 | bool | |
4862826d | 429 | alias_set_subset_of (alias_set_type set1, alias_set_type set2) |
c58936b6 | 430 | { |
02ced957 | 431 | alias_set_entry *ase2; |
c58936b6 | 432 | |
bd04cddf JH |
433 | /* Disable TBAA oracle with !flag_strict_aliasing. */ |
434 | if (!flag_strict_aliasing) | |
435 | return true; | |
436 | ||
c58936b6 DB |
437 | /* Everything is a subset of the "aliases everything" set. */ |
438 | if (set2 == 0) | |
439 | return true; | |
440 | ||
6e042ef4 JH |
441 | /* Check if set1 is a subset of set2. */ |
442 | ase2 = get_alias_set_entry (set2); | |
443 | if (ase2 != 0 | |
444 | && (ase2->has_zero_child | |
445 | || (ase2->children && ase2->children->get (set1)))) | |
c58936b6 | 446 | return true; |
6e042ef4 JH |
447 | |
448 | /* As a special case we consider alias set of "void *" to be both subset | |
449 | and superset of every alias set of a pointer. This extra symmetry does | |
450 | not matter for alias_sets_conflict_p but it makes aliasing_component_refs_p | |
451 | to return true on the following testcase: | |
452 | ||
453 | void *ptr; | |
454 | char **ptr2=(char **)&ptr; | |
455 | *ptr2 = ... | |
456 | ||
457 | Additionally if a set contains universal pointer, we consider every pointer | |
458 | to be a subset of it, but we do not represent this explicitely - doing so | |
459 | would require us to update transitive closure each time we introduce new | |
460 | pointer type. This makes aliasing_component_refs_p to return true | |
461 | on the following testcase: | |
462 | ||
463 | struct a {void *ptr;} | |
464 | char **ptr = (char **)&a.ptr; | |
465 | ptr = ... | |
466 | ||
467 | This makes void * truly universal pointer type. See pointer handling in | |
468 | get_alias_set for more details. */ | |
469 | if (ase2 && ase2->has_pointer) | |
470 | { | |
02ced957 | 471 | alias_set_entry *ase1 = get_alias_set_entry (set1); |
6e042ef4 JH |
472 | |
473 | if (ase1 && ase1->is_pointer) | |
474 | { | |
475 | alias_set_type voidptr_set = TYPE_ALIAS_SET (ptr_type_node); | |
476 | /* If one is ptr_type_node and other is pointer, then we consider | |
477 | them subset of each other. */ | |
478 | if (set1 == voidptr_set || set2 == voidptr_set) | |
479 | return true; | |
480 | /* If SET2 contains universal pointer's alias set, then we consdier | |
481 | every (non-universal) pointer. */ | |
482 | if (ase2->children && set1 != voidptr_set | |
483 | && ase2->children->get (voidptr_set)) | |
484 | return true; | |
485 | } | |
486 | } | |
c58936b6 DB |
487 | return false; |
488 | } | |
489 | ||
1da68f56 RK |
490 | /* Return 1 if the two specified alias sets may conflict. */ |
491 | ||
492 | int | |
4862826d | 493 | alias_sets_conflict_p (alias_set_type set1, alias_set_type set2) |
1da68f56 | 494 | { |
02ced957 TS |
495 | alias_set_entry *ase1; |
496 | alias_set_entry *ase2; | |
1da68f56 | 497 | |
836f7794 EB |
498 | /* The easy case. */ |
499 | if (alias_sets_must_conflict_p (set1, set2)) | |
1da68f56 | 500 | return 1; |
3932261a | 501 | |
3bdf5ad1 | 502 | /* See if the first alias set is a subset of the second. */ |
6e042ef4 JH |
503 | ase1 = get_alias_set_entry (set1); |
504 | if (ase1 != 0 | |
505 | && ase1->children && ase1->children->get (set2)) | |
3ecf9d13 JH |
506 | { |
507 | ++alias_stats.num_dag; | |
508 | return 1; | |
509 | } | |
3932261a MM |
510 | |
511 | /* Now do the same, but with the alias sets reversed. */ | |
6e042ef4 JH |
512 | ase2 = get_alias_set_entry (set2); |
513 | if (ase2 != 0 | |
514 | && ase2->children && ase2->children->get (set1)) | |
3ecf9d13 JH |
515 | { |
516 | ++alias_stats.num_dag; | |
517 | return 1; | |
518 | } | |
6e042ef4 JH |
519 | |
520 | /* We want void * to be compatible with any other pointer without | |
521 | really dropping it to alias set 0. Doing so would make it | |
522 | compatible with all non-pointer types too. | |
523 | ||
524 | This is not strictly necessary by the C/C++ language | |
525 | standards, but avoids common type punning mistakes. In | |
526 | addition to that, we need the existence of such universal | |
527 | pointer to implement Fortran's C_PTR type (which is defined as | |
528 | type compatible with all C pointers). */ | |
529 | if (ase1 && ase2 && ase1->has_pointer && ase2->has_pointer) | |
530 | { | |
531 | alias_set_type voidptr_set = TYPE_ALIAS_SET (ptr_type_node); | |
532 | ||
533 | /* If one of the sets corresponds to universal pointer, | |
534 | we consider it to conflict with anything that is | |
535 | or contains pointer. */ | |
536 | if (set1 == voidptr_set || set2 == voidptr_set) | |
537 | { | |
538 | ++alias_stats.num_universal; | |
539 | return true; | |
540 | } | |
541 | /* If one of sets is (non-universal) pointer and the other | |
542 | contains universal pointer, we also get conflict. */ | |
543 | if (ase1->is_pointer && set2 != voidptr_set | |
544 | && ase2->children && ase2->children->get (voidptr_set)) | |
545 | { | |
546 | ++alias_stats.num_universal; | |
547 | return true; | |
548 | } | |
549 | if (ase2->is_pointer && set1 != voidptr_set | |
550 | && ase1->children && ase1->children->get (voidptr_set)) | |
551 | { | |
552 | ++alias_stats.num_universal; | |
553 | return true; | |
554 | } | |
555 | } | |
556 | ||
3ecf9d13 | 557 | ++alias_stats.num_disambiguated; |
3932261a | 558 | |
1da68f56 | 559 | /* The two alias sets are distinct and neither one is the |
836f7794 | 560 | child of the other. Therefore, they cannot conflict. */ |
1da68f56 | 561 | return 0; |
3932261a | 562 | } |
5399d643 | 563 | |
836f7794 | 564 | /* Return 1 if the two specified alias sets will always conflict. */ |
5399d643 JW |
565 | |
566 | int | |
4862826d | 567 | alias_sets_must_conflict_p (alias_set_type set1, alias_set_type set2) |
5399d643 | 568 | { |
bd04cddf JH |
569 | /* Disable TBAA oracle with !flag_strict_aliasing. */ |
570 | if (!flag_strict_aliasing) | |
571 | return 1; | |
3ecf9d13 JH |
572 | if (set1 == 0 || set2 == 0) |
573 | { | |
574 | ++alias_stats.num_alias_zero; | |
575 | return 1; | |
576 | } | |
577 | if (set1 == set2) | |
578 | { | |
579 | ++alias_stats.num_same_alias_set; | |
580 | return 1; | |
581 | } | |
5399d643 JW |
582 | |
583 | return 0; | |
584 | } | |
585 | ||
1da68f56 RK |
586 | /* Return 1 if any MEM object of type T1 will always conflict (using the |
587 | dependency routines in this file) with any MEM object of type T2. | |
588 | This is used when allocating temporary storage. If T1 and/or T2 are | |
589 | NULL_TREE, it means we know nothing about the storage. */ | |
590 | ||
591 | int | |
4682ae04 | 592 | objects_must_conflict_p (tree t1, tree t2) |
1da68f56 | 593 | { |
4862826d | 594 | alias_set_type set1, set2; |
82d610ec | 595 | |
e8ea2809 RK |
596 | /* If neither has a type specified, we don't know if they'll conflict |
597 | because we may be using them to store objects of various types, for | |
598 | example the argument and local variables areas of inlined functions. */ | |
981a4c34 | 599 | if (t1 == 0 && t2 == 0) |
e8ea2809 RK |
600 | return 0; |
601 | ||
1da68f56 | 602 | /* If they are the same type, they must conflict. */ |
3ecf9d13 JH |
603 | if (t1 == t2) |
604 | { | |
605 | ++alias_stats.num_same_objects; | |
606 | return 1; | |
607 | } | |
608 | /* Likewise if both are volatile. */ | |
609 | if (t1 != 0 && TYPE_VOLATILE (t1) && t2 != 0 && TYPE_VOLATILE (t2)) | |
610 | { | |
611 | ++alias_stats.num_volatile; | |
612 | return 1; | |
613 | } | |
1da68f56 | 614 | |
82d610ec RK |
615 | set1 = t1 ? get_alias_set (t1) : 0; |
616 | set2 = t2 ? get_alias_set (t2) : 0; | |
1da68f56 | 617 | |
836f7794 EB |
618 | /* We can't use alias_sets_conflict_p because we must make sure |
619 | that every subtype of t1 will conflict with every subtype of | |
82d610ec RK |
620 | t2 for which a pair of subobjects of these respective subtypes |
621 | overlaps on the stack. */ | |
836f7794 | 622 | return alias_sets_must_conflict_p (set1, set2); |
1da68f56 RK |
623 | } |
624 | \f | |
9640ff5a JH |
625 | /* Return true if T is an end of the access path which can be used |
626 | by type based alias oracle. */ | |
627 | ||
628 | bool | |
629 | ends_tbaa_access_path_p (const_tree t) | |
630 | { | |
631 | switch (TREE_CODE (t)) | |
632 | { | |
633 | case COMPONENT_REF: | |
634 | if (DECL_NONADDRESSABLE_P (TREE_OPERAND (t, 1))) | |
635 | return true; | |
636 | /* Permit type-punning when accessing a union, provided the access | |
637 | is directly through the union. For example, this code does not | |
638 | permit taking the address of a union member and then storing | |
639 | through it. Even the type-punning allowed here is a GCC | |
640 | extension, albeit a common and useful one; the C standard says | |
641 | that such accesses have implementation-defined behavior. */ | |
642 | else if (TREE_CODE (TREE_TYPE (TREE_OPERAND (t, 0))) == UNION_TYPE) | |
643 | return true; | |
644 | break; | |
645 | ||
646 | case ARRAY_REF: | |
647 | case ARRAY_RANGE_REF: | |
648 | if (TYPE_NONALIASED_COMPONENT (TREE_TYPE (TREE_OPERAND (t, 0)))) | |
649 | return true; | |
650 | break; | |
651 | ||
652 | case REALPART_EXPR: | |
653 | case IMAGPART_EXPR: | |
654 | break; | |
655 | ||
656 | case BIT_FIELD_REF: | |
657 | case VIEW_CONVERT_EXPR: | |
658 | /* Bitfields and casts are never addressable. */ | |
659 | return true; | |
660 | break; | |
661 | ||
662 | default: | |
663 | gcc_unreachable (); | |
664 | } | |
665 | return false; | |
666 | } | |
667 | ||
b4ada065 RB |
668 | /* Return the outermost parent of component present in the chain of |
669 | component references handled by get_inner_reference in T with the | |
670 | following property: | |
dc3221e1 | 671 | - the component is non-addressable |
b4ada065 RB |
672 | or NULL_TREE if no such parent exists. In the former cases, the alias |
673 | set of this parent is the alias set that must be used for T itself. */ | |
674 | ||
675 | tree | |
676 | component_uses_parent_alias_set_from (const_tree t) | |
6e24b709 | 677 | { |
b4ada065 | 678 | const_tree found = NULL_TREE; |
afe84921 | 679 | |
b4ada065 RB |
680 | while (handled_component_p (t)) |
681 | { | |
9640ff5a JH |
682 | if (ends_tbaa_access_path_p (t)) |
683 | found = t; | |
afe84921 RH |
684 | |
685 | t = TREE_OPERAND (t, 0); | |
686 | } | |
b4ada065 RB |
687 | |
688 | if (found) | |
689 | return TREE_OPERAND (found, 0); | |
690 | ||
691 | return NULL_TREE; | |
6e24b709 RK |
692 | } |
693 | ||
f40333af RB |
694 | |
695 | /* Return whether the pointer-type T effective for aliasing may | |
696 | access everything and thus the reference has to be assigned | |
697 | alias-set zero. */ | |
698 | ||
699 | static bool | |
700 | ref_all_alias_ptr_type_p (const_tree t) | |
701 | { | |
702 | return (TREE_CODE (TREE_TYPE (t)) == VOID_TYPE | |
703 | || TYPE_REF_CAN_ALIAS_ALL (t)); | |
704 | } | |
705 | ||
5006671f RG |
706 | /* Return the alias set for the memory pointed to by T, which may be |
707 | either a type or an expression. Return -1 if there is nothing | |
708 | special about dereferencing T. */ | |
709 | ||
710 | static alias_set_type | |
711 | get_deref_alias_set_1 (tree t) | |
712 | { | |
5b21f0f3 | 713 | /* All we care about is the type. */ |
5006671f | 714 | if (! TYPE_P (t)) |
5b21f0f3 | 715 | t = TREE_TYPE (t); |
5006671f RG |
716 | |
717 | /* If we have an INDIRECT_REF via a void pointer, we don't | |
718 | know anything about what that might alias. Likewise if the | |
719 | pointer is marked that way. */ | |
f40333af | 720 | if (ref_all_alias_ptr_type_p (t)) |
5006671f RG |
721 | return 0; |
722 | ||
723 | return -1; | |
724 | } | |
725 | ||
726 | /* Return the alias set for the memory pointed to by T, which may be | |
727 | either a type or an expression. */ | |
728 | ||
729 | alias_set_type | |
730 | get_deref_alias_set (tree t) | |
731 | { | |
f40333af RB |
732 | /* If we're not doing any alias analysis, just assume everything |
733 | aliases everything else. */ | |
734 | if (!flag_strict_aliasing) | |
735 | return 0; | |
736 | ||
5006671f RG |
737 | alias_set_type set = get_deref_alias_set_1 (t); |
738 | ||
739 | /* Fall back to the alias-set of the pointed-to type. */ | |
740 | if (set == -1) | |
741 | { | |
742 | if (! TYPE_P (t)) | |
743 | t = TREE_TYPE (t); | |
744 | set = get_alias_set (TREE_TYPE (t)); | |
745 | } | |
746 | ||
747 | return set; | |
748 | } | |
749 | ||
f40333af RB |
750 | /* Return the pointer-type relevant for TBAA purposes from the |
751 | memory reference tree *T or NULL_TREE in which case *T is | |
752 | adjusted to point to the outermost component reference that | |
753 | can be used for assigning an alias set. */ | |
754 | ||
d119f34c | 755 | tree |
f40333af RB |
756 | reference_alias_ptr_type_1 (tree *t) |
757 | { | |
758 | tree inner; | |
759 | ||
760 | /* Get the base object of the reference. */ | |
761 | inner = *t; | |
762 | while (handled_component_p (inner)) | |
763 | { | |
764 | /* If there is a VIEW_CONVERT_EXPR in the chain we cannot use | |
765 | the type of any component references that wrap it to | |
766 | determine the alias-set. */ | |
767 | if (TREE_CODE (inner) == VIEW_CONVERT_EXPR) | |
768 | *t = TREE_OPERAND (inner, 0); | |
769 | inner = TREE_OPERAND (inner, 0); | |
770 | } | |
771 | ||
772 | /* Handle pointer dereferences here, they can override the | |
773 | alias-set. */ | |
774 | if (INDIRECT_REF_P (inner) | |
775 | && ref_all_alias_ptr_type_p (TREE_TYPE (TREE_OPERAND (inner, 0)))) | |
776 | return TREE_TYPE (TREE_OPERAND (inner, 0)); | |
777 | else if (TREE_CODE (inner) == TARGET_MEM_REF) | |
778 | return TREE_TYPE (TMR_OFFSET (inner)); | |
779 | else if (TREE_CODE (inner) == MEM_REF | |
780 | && ref_all_alias_ptr_type_p (TREE_TYPE (TREE_OPERAND (inner, 1)))) | |
781 | return TREE_TYPE (TREE_OPERAND (inner, 1)); | |
782 | ||
783 | /* If the innermost reference is a MEM_REF that has a | |
784 | conversion embedded treat it like a VIEW_CONVERT_EXPR above, | |
785 | using the memory access type for determining the alias-set. */ | |
786 | if (TREE_CODE (inner) == MEM_REF | |
787 | && (TYPE_MAIN_VARIANT (TREE_TYPE (inner)) | |
788 | != TYPE_MAIN_VARIANT | |
789 | (TREE_TYPE (TREE_TYPE (TREE_OPERAND (inner, 1)))))) | |
790 | return TREE_TYPE (TREE_OPERAND (inner, 1)); | |
791 | ||
b4ada065 RB |
792 | /* Otherwise, pick up the outermost object that we could have |
793 | a pointer to. */ | |
794 | tree tem = component_uses_parent_alias_set_from (*t); | |
795 | if (tem) | |
796 | *t = tem; | |
f40333af RB |
797 | |
798 | return NULL_TREE; | |
799 | } | |
800 | ||
801 | /* Return the pointer-type relevant for TBAA purposes from the | |
802 | gimple memory reference tree T. This is the type to be used for | |
803 | the offset operand of MEM_REF or TARGET_MEM_REF replacements of T | |
804 | and guarantees that get_alias_set will return the same alias | |
805 | set for T and the replacement. */ | |
806 | ||
807 | tree | |
808 | reference_alias_ptr_type (tree t) | |
809 | { | |
ebc1b29e RB |
810 | /* If the frontend assigns this alias-set zero, preserve that. */ |
811 | if (lang_hooks.get_alias_set (t) == 0) | |
812 | return ptr_type_node; | |
813 | ||
f40333af RB |
814 | tree ptype = reference_alias_ptr_type_1 (&t); |
815 | /* If there is a given pointer type for aliasing purposes, return it. */ | |
816 | if (ptype != NULL_TREE) | |
817 | return ptype; | |
818 | ||
819 | /* Otherwise build one from the outermost component reference we | |
820 | may use. */ | |
821 | if (TREE_CODE (t) == MEM_REF | |
822 | || TREE_CODE (t) == TARGET_MEM_REF) | |
823 | return TREE_TYPE (TREE_OPERAND (t, 1)); | |
824 | else | |
825 | return build_pointer_type (TYPE_MAIN_VARIANT (TREE_TYPE (t))); | |
826 | } | |
827 | ||
828 | /* Return whether the pointer-types T1 and T2 used to determine | |
829 | two alias sets of two references will yield the same answer | |
830 | from get_deref_alias_set. */ | |
831 | ||
832 | bool | |
833 | alias_ptr_types_compatible_p (tree t1, tree t2) | |
834 | { | |
835 | if (TYPE_MAIN_VARIANT (t1) == TYPE_MAIN_VARIANT (t2)) | |
836 | return true; | |
837 | ||
838 | if (ref_all_alias_ptr_type_p (t1) | |
839 | || ref_all_alias_ptr_type_p (t2)) | |
840 | return false; | |
841 | ||
33e8e0ee ML |
842 | /* This function originally abstracts from simply comparing |
843 | get_deref_alias_set so that we are sure this still computes | |
844 | the same result after LTO type merging is applied. | |
845 | When in LTO type merging is done we can actually do this compare. | |
846 | */ | |
847 | if (in_lto_p) | |
848 | return get_deref_alias_set (t1) == get_deref_alias_set (t2); | |
849 | else | |
850 | return (TYPE_MAIN_VARIANT (TREE_TYPE (t1)) | |
851 | == TYPE_MAIN_VARIANT (TREE_TYPE (t2))); | |
f40333af RB |
852 | } |
853 | ||
6e042ef4 JH |
854 | /* Create emptry alias set entry. */ |
855 | ||
02ced957 | 856 | alias_set_entry * |
6e042ef4 JH |
857 | init_alias_set_entry (alias_set_type set) |
858 | { | |
02ced957 | 859 | alias_set_entry *ase = ggc_alloc<alias_set_entry> (); |
6e042ef4 JH |
860 | ase->alias_set = set; |
861 | ase->children = NULL; | |
862 | ase->has_zero_child = false; | |
863 | ase->is_pointer = false; | |
864 | ase->has_pointer = false; | |
865 | gcc_checking_assert (!get_alias_set_entry (set)); | |
866 | (*alias_sets)[set] = ase; | |
867 | return ase; | |
868 | } | |
869 | ||
3bdf5ad1 RK |
870 | /* Return the alias set for T, which may be either a type or an |
871 | expression. Call language-specific routine for help, if needed. */ | |
872 | ||
4862826d | 873 | alias_set_type |
4682ae04 | 874 | get_alias_set (tree t) |
3bdf5ad1 | 875 | { |
4862826d | 876 | alias_set_type set; |
3bdf5ad1 | 877 | |
67914693 | 878 | /* We cannot give up with -fno-strict-aliasing because we need to build |
63f56527 | 879 | proper type representations for possible functions which are built with |
e8444ca6 | 880 | -fstrict-aliasing. */ |
bd04cddf JH |
881 | |
882 | /* return 0 if this or its type is an error. */ | |
883 | if (t == error_mark_node | |
3bdf5ad1 RK |
884 | || (! TYPE_P (t) |
885 | && (TREE_TYPE (t) == 0 || TREE_TYPE (t) == error_mark_node))) | |
886 | return 0; | |
887 | ||
888 | /* We can be passed either an expression or a type. This and the | |
f47e9b4e RK |
889 | language-specific routine may make mutually-recursive calls to each other |
890 | to figure out what to do. At each juncture, we see if this is a tree | |
891 | that the language may need to handle specially. First handle things that | |
738cc472 | 892 | aren't types. */ |
f824e5c3 | 893 | if (! TYPE_P (t)) |
3bdf5ad1 | 894 | { |
70f34814 RG |
895 | /* Give the language a chance to do something with this tree |
896 | before we look at it. */ | |
8ac61af7 | 897 | STRIP_NOPS (t); |
ae2bcd98 | 898 | set = lang_hooks.get_alias_set (t); |
8ac61af7 RK |
899 | if (set != -1) |
900 | return set; | |
901 | ||
f40333af RB |
902 | /* Get the alias pointer-type to use or the outermost object |
903 | that we could have a pointer to. */ | |
904 | tree ptype = reference_alias_ptr_type_1 (&t); | |
905 | if (ptype != NULL) | |
906 | return get_deref_alias_set (ptype); | |
f824e5c3 | 907 | |
738cc472 RK |
908 | /* If we've already determined the alias set for a decl, just return |
909 | it. This is necessary for C++ anonymous unions, whose component | |
910 | variables don't look like union members (boo!). */ | |
8813a647 | 911 | if (VAR_P (t) |
3c0cb5de | 912 | && DECL_RTL_SET_P (t) && MEM_P (DECL_RTL (t))) |
5755cd38 JM |
913 | return MEM_ALIAS_SET (DECL_RTL (t)); |
914 | ||
f824e5c3 RK |
915 | /* Now all we care about is the type. */ |
916 | t = TREE_TYPE (t); | |
3bdf5ad1 RK |
917 | } |
918 | ||
3bdf5ad1 | 919 | /* Variant qualifiers don't affect the alias set, so get the main |
daad0278 | 920 | variant. */ |
3bdf5ad1 | 921 | t = TYPE_MAIN_VARIANT (t); |
daad0278 | 922 | |
350792ff RB |
923 | if (AGGREGATE_TYPE_P (t) |
924 | && TYPE_TYPELESS_STORAGE (t)) | |
925 | return 0; | |
926 | ||
daad0278 RG |
927 | /* Always use the canonical type as well. If this is a type that |
928 | requires structural comparisons to identify compatible types | |
929 | use alias set zero. */ | |
930 | if (TYPE_STRUCTURAL_EQUALITY_P (t)) | |
cb9c2485 JM |
931 | { |
932 | /* Allow the language to specify another alias set for this | |
933 | type. */ | |
934 | set = lang_hooks.get_alias_set (t); | |
935 | if (set != -1) | |
936 | return set; | |
aea50b45 | 937 | /* Handle structure type equality for pointer types, arrays and vectors. |
63f56527 | 938 | This is easy to do, because the code below ignores canonical types on |
aea50b45 | 939 | these anyway. This is important for LTO, where TYPE_CANONICAL for |
63f56527 | 940 | pointers cannot be meaningfully computed by the frontend. */ |
aea50b45 | 941 | if (canonical_type_used_p (t)) |
f85d2487 JH |
942 | { |
943 | /* In LTO we set canonical types for all types where it makes | |
944 | sense to do so. Double check we did not miss some type. */ | |
945 | gcc_checking_assert (!in_lto_p || !type_with_alias_set_p (t)); | |
946 | return 0; | |
947 | } | |
948 | } | |
949 | else | |
950 | { | |
951 | t = TYPE_CANONICAL (t); | |
952 | gcc_checking_assert (!TYPE_STRUCTURAL_EQUALITY_P (t)); | |
cb9c2485 | 953 | } |
daad0278 RG |
954 | |
955 | /* If this is a type with a known alias set, return it. */ | |
ba6a6a1d | 956 | gcc_checking_assert (t == TYPE_MAIN_VARIANT (t)); |
738cc472 | 957 | if (TYPE_ALIAS_SET_KNOWN_P (t)) |
3bdf5ad1 RK |
958 | return TYPE_ALIAS_SET (t); |
959 | ||
36784d0e RG |
960 | /* We don't want to set TYPE_ALIAS_SET for incomplete types. */ |
961 | if (!COMPLETE_TYPE_P (t)) | |
962 | { | |
963 | /* For arrays with unknown size the conservative answer is the | |
964 | alias set of the element type. */ | |
965 | if (TREE_CODE (t) == ARRAY_TYPE) | |
966 | return get_alias_set (TREE_TYPE (t)); | |
967 | ||
968 | /* But return zero as a conservative answer for incomplete types. */ | |
969 | return 0; | |
970 | } | |
971 | ||
3bdf5ad1 | 972 | /* See if the language has special handling for this type. */ |
ae2bcd98 | 973 | set = lang_hooks.get_alias_set (t); |
8ac61af7 | 974 | if (set != -1) |
738cc472 | 975 | return set; |
2bf105ab | 976 | |
3bdf5ad1 RK |
977 | /* There are no objects of FUNCTION_TYPE, so there's no point in |
978 | using up an alias set for them. (There are, of course, pointers | |
979 | and references to functions, but that's different.) */ | |
7be7d292 | 980 | else if (TREE_CODE (t) == FUNCTION_TYPE || TREE_CODE (t) == METHOD_TYPE) |
3bdf5ad1 | 981 | set = 0; |
74d86f4f RH |
982 | |
983 | /* Unless the language specifies otherwise, let vector types alias | |
984 | their components. This avoids some nasty type punning issues in | |
985 | normal usage. And indeed lets vectors be treated more like an | |
986 | array slice. */ | |
987 | else if (TREE_CODE (t) == VECTOR_TYPE) | |
988 | set = get_alias_set (TREE_TYPE (t)); | |
989 | ||
4653cae5 RG |
990 | /* Unless the language specifies otherwise, treat array types the |
991 | same as their components. This avoids the asymmetry we get | |
992 | through recording the components. Consider accessing a | |
993 | character(kind=1) through a reference to a character(kind=1)[1:1]. | |
994 | Or consider if we want to assign integer(kind=4)[0:D.1387] and | |
995 | integer(kind=4)[4] the same alias set or not. | |
996 | Just be pragmatic here and make sure the array and its element | |
997 | type get the same alias set assigned. */ | |
aea50b45 JH |
998 | else if (TREE_CODE (t) == ARRAY_TYPE |
999 | && (!TYPE_NONALIASED_COMPONENT (t) | |
1000 | || TYPE_STRUCTURAL_EQUALITY_P (t))) | |
4653cae5 RG |
1001 | set = get_alias_set (TREE_TYPE (t)); |
1002 | ||
0ceb0201 RG |
1003 | /* From the former common C and C++ langhook implementation: |
1004 | ||
1005 | Unfortunately, there is no canonical form of a pointer type. | |
1006 | In particular, if we have `typedef int I', then `int *', and | |
1007 | `I *' are different types. So, we have to pick a canonical | |
1008 | representative. We do this below. | |
1009 | ||
1010 | Technically, this approach is actually more conservative that | |
1011 | it needs to be. In particular, `const int *' and `int *' | |
1012 | should be in different alias sets, according to the C and C++ | |
1013 | standard, since their types are not the same, and so, | |
1014 | technically, an `int **' and `const int **' cannot point at | |
1015 | the same thing. | |
1016 | ||
1017 | But, the standard is wrong. In particular, this code is | |
1018 | legal C++: | |
1019 | ||
1020 | int *ip; | |
1021 | int **ipp = &ip; | |
1022 | const int* const* cipp = ipp; | |
1023 | And, it doesn't make sense for that to be legal unless you | |
1024 | can dereference IPP and CIPP. So, we ignore cv-qualifiers on | |
1025 | the pointed-to types. This issue has been reported to the | |
1026 | C++ committee. | |
1027 | ||
6e042ef4 JH |
1028 | For this reason go to canonical type of the unqalified pointer type. |
1029 | Until GCC 6 this code set all pointers sets to have alias set of | |
1030 | ptr_type_node but that is a bad idea, because it prevents disabiguations | |
1031 | in between pointers. For Firefox this accounts about 20% of all | |
1032 | disambiguations in the program. */ | |
f85d2487 | 1033 | else if (POINTER_TYPE_P (t) && t != ptr_type_node) |
6e042ef4 JH |
1034 | { |
1035 | tree p; | |
1036 | auto_vec <bool, 8> reference; | |
1037 | ||
1038 | /* Unnest all pointers and references. | |
f85d2487 JH |
1039 | We also want to make pointer to array/vector equivalent to pointer to |
1040 | its element (see the reasoning above). Skip all those types, too. */ | |
6e042ef4 | 1041 | for (p = t; POINTER_TYPE_P (p) |
aea50b45 JH |
1042 | || (TREE_CODE (p) == ARRAY_TYPE |
1043 | && (!TYPE_NONALIASED_COMPONENT (p) | |
1044 | || !COMPLETE_TYPE_P (p) | |
1045 | || TYPE_STRUCTURAL_EQUALITY_P (p))) | |
f85d2487 | 1046 | || TREE_CODE (p) == VECTOR_TYPE; |
6e042ef4 JH |
1047 | p = TREE_TYPE (p)) |
1048 | { | |
63f56527 SL |
1049 | /* Ada supports recursive pointers. Instead of doing recursion |
1050 | check, just give up once the preallocated space of 8 elements | |
1051 | is up. In this case just punt to void * alias set. */ | |
54363f8a JH |
1052 | if (reference.length () == 8) |
1053 | { | |
1054 | p = ptr_type_node; | |
1055 | break; | |
1056 | } | |
6e042ef4 | 1057 | if (TREE_CODE (p) == REFERENCE_TYPE) |
f85d2487 JH |
1058 | /* In LTO we want languages that use references to be compatible |
1059 | with languages that use pointers. */ | |
1060 | reference.safe_push (true && !in_lto_p); | |
6e042ef4 JH |
1061 | if (TREE_CODE (p) == POINTER_TYPE) |
1062 | reference.safe_push (false); | |
1063 | } | |
1064 | p = TYPE_MAIN_VARIANT (p); | |
1065 | ||
63f56527 | 1066 | /* In LTO for C++ programs we can turn incomplete types to complete |
e4b44fd7 JH |
1067 | using ODR name lookup. */ |
1068 | if (in_lto_p && TYPE_STRUCTURAL_EQUALITY_P (p) && odr_type_p (p)) | |
1069 | { | |
1070 | p = prevailing_odr_type (p); | |
1071 | gcc_checking_assert (TYPE_MAIN_VARIANT (p) == p); | |
1072 | } | |
1073 | ||
6e042ef4 JH |
1074 | /* Make void * compatible with char * and also void **. |
1075 | Programs are commonly violating TBAA by this. | |
1076 | ||
1077 | We also make void * to conflict with every pointer | |
1078 | (see record_component_aliases) and thus it is safe it to use it for | |
1079 | pointers to types with TYPE_STRUCTURAL_EQUALITY_P. */ | |
1080 | if (TREE_CODE (p) == VOID_TYPE || TYPE_STRUCTURAL_EQUALITY_P (p)) | |
1081 | set = get_alias_set (ptr_type_node); | |
1082 | else | |
1083 | { | |
f85d2487 | 1084 | /* Rebuild pointer type starting from canonical types using |
6e042ef4 JH |
1085 | unqualified pointers and references only. This way all such |
1086 | pointers will have the same alias set and will conflict with | |
1087 | each other. | |
1088 | ||
1089 | Most of time we already have pointers or references of a given type. | |
1090 | If not we build new one just to be sure that if someone later | |
1091 | (probably only middle-end can, as we should assign all alias | |
1092 | classes only after finishing translation unit) builds the pointer | |
1093 | type, the canonical type will match. */ | |
1094 | p = TYPE_CANONICAL (p); | |
1095 | while (!reference.is_empty ()) | |
1096 | { | |
1097 | if (reference.pop ()) | |
1098 | p = build_reference_type (p); | |
1099 | else | |
1100 | p = build_pointer_type (p); | |
f85d2487 JH |
1101 | gcc_checking_assert (p == TYPE_MAIN_VARIANT (p)); |
1102 | /* build_pointer_type should always return the canonical type. | |
1103 | For LTO TYPE_CANOINCAL may be NULL, because we do not compute | |
1104 | them. Be sure that frontends do not glob canonical types of | |
1105 | pointers in unexpected way and that p == TYPE_CANONICAL (p) | |
1106 | in all other cases. */ | |
1107 | gcc_checking_assert (!TYPE_CANONICAL (p) | |
1108 | || p == TYPE_CANONICAL (p)); | |
6e042ef4 | 1109 | } |
6e042ef4 JH |
1110 | |
1111 | /* Assign the alias set to both p and t. | |
67914693 | 1112 | We cannot call get_alias_set (p) here as that would trigger |
6e042ef4 JH |
1113 | infinite recursion when p == t. In other cases it would just |
1114 | trigger unnecesary legwork of rebuilding the pointer again. */ | |
ba6a6a1d | 1115 | gcc_checking_assert (p == TYPE_MAIN_VARIANT (p)); |
6e042ef4 JH |
1116 | if (TYPE_ALIAS_SET_KNOWN_P (p)) |
1117 | set = TYPE_ALIAS_SET (p); | |
1118 | else | |
1119 | { | |
1120 | set = new_alias_set (); | |
1121 | TYPE_ALIAS_SET (p) = set; | |
1122 | } | |
1123 | } | |
1124 | } | |
f85d2487 JH |
1125 | /* Alias set of ptr_type_node is special and serve as universal pointer which |
1126 | is TBAA compatible with every other pointer type. Be sure we have the | |
1127 | alias set built even for LTO which otherwise keeps all TYPE_CANONICAL | |
1128 | of pointer types NULL. */ | |
1129 | else if (t == ptr_type_node) | |
1130 | set = new_alias_set (); | |
0ceb0201 | 1131 | |
7be7d292 | 1132 | /* Otherwise make a new alias set for this type. */ |
3bdf5ad1 | 1133 | else |
96d91dcf RG |
1134 | { |
1135 | /* Each canonical type gets its own alias set, so canonical types | |
1136 | shouldn't form a tree. It doesn't really matter for types | |
1137 | we handle specially above, so only check it where it possibly | |
1138 | would result in a bogus alias set. */ | |
1139 | gcc_checking_assert (TYPE_CANONICAL (t) == t); | |
1140 | ||
1141 | set = new_alias_set (); | |
1142 | } | |
3bdf5ad1 RK |
1143 | |
1144 | TYPE_ALIAS_SET (t) = set; | |
2bf105ab | 1145 | |
7be7d292 EB |
1146 | /* If this is an aggregate type or a complex type, we must record any |
1147 | component aliasing information. */ | |
1d79fd2c | 1148 | if (AGGREGATE_TYPE_P (t) || TREE_CODE (t) == COMPLEX_TYPE) |
2bf105ab RK |
1149 | record_component_aliases (t); |
1150 | ||
6e042ef4 JH |
1151 | /* We treat pointer types specially in alias_set_subset_of. */ |
1152 | if (POINTER_TYPE_P (t) && set) | |
1153 | { | |
02ced957 | 1154 | alias_set_entry *ase = get_alias_set_entry (set); |
6e042ef4 JH |
1155 | if (!ase) |
1156 | ase = init_alias_set_entry (set); | |
1157 | ase->is_pointer = true; | |
1158 | ase->has_pointer = true; | |
1159 | } | |
1160 | ||
3bdf5ad1 RK |
1161 | return set; |
1162 | } | |
1163 | ||
1164 | /* Return a brand-new alias set. */ | |
1165 | ||
4862826d | 1166 | alias_set_type |
4682ae04 | 1167 | new_alias_set (void) |
3bdf5ad1 | 1168 | { |
bd04cddf JH |
1169 | if (alias_sets == 0) |
1170 | vec_safe_push (alias_sets, (alias_set_entry *) NULL); | |
1171 | vec_safe_push (alias_sets, (alias_set_entry *) NULL); | |
1172 | return alias_sets->length () - 1; | |
3bdf5ad1 | 1173 | } |
3932261a | 1174 | |
01d28c3f JM |
1175 | /* Indicate that things in SUBSET can alias things in SUPERSET, but that |
1176 | not everything that aliases SUPERSET also aliases SUBSET. For example, | |
1177 | in C, a store to an `int' can alias a load of a structure containing an | |
1178 | `int', and vice versa. But it can't alias a load of a 'double' member | |
1179 | of the same structure. Here, the structure would be the SUPERSET and | |
1180 | `int' the SUBSET. This relationship is also described in the comment at | |
1181 | the beginning of this file. | |
1182 | ||
1183 | This function should be called only once per SUPERSET/SUBSET pair. | |
3932261a MM |
1184 | |
1185 | It is illegal for SUPERSET to be zero; everything is implicitly a | |
1186 | subset of alias set zero. */ | |
1187 | ||
794511d2 | 1188 | void |
4862826d | 1189 | record_alias_subset (alias_set_type superset, alias_set_type subset) |
3932261a | 1190 | { |
02ced957 TS |
1191 | alias_set_entry *superset_entry; |
1192 | alias_set_entry *subset_entry; | |
3932261a | 1193 | |
f47e9b4e RK |
1194 | /* It is possible in complex type situations for both sets to be the same, |
1195 | in which case we can ignore this operation. */ | |
1196 | if (superset == subset) | |
1197 | return; | |
1198 | ||
298e6adc | 1199 | gcc_assert (superset); |
3932261a MM |
1200 | |
1201 | superset_entry = get_alias_set_entry (superset); | |
ca7fd9cd | 1202 | if (superset_entry == 0) |
3932261a MM |
1203 | { |
1204 | /* Create an entry for the SUPERSET, so that we have a place to | |
1205 | attach the SUBSET. */ | |
6e042ef4 | 1206 | superset_entry = init_alias_set_entry (superset); |
3932261a MM |
1207 | } |
1208 | ||
2bf105ab RK |
1209 | if (subset == 0) |
1210 | superset_entry->has_zero_child = 1; | |
1211 | else | |
1212 | { | |
6e042ef4 JH |
1213 | if (!superset_entry->children) |
1214 | superset_entry->children | |
fb5c464a | 1215 | = hash_map<alias_set_hash, int>::create_ggc (64); |
6c577667 RB |
1216 | |
1217 | /* Enter the SUBSET itself as a child of the SUPERSET. If it was | |
1218 | already there we're done. */ | |
1219 | if (superset_entry->children->put (subset, 0)) | |
1220 | return; | |
1221 | ||
1222 | subset_entry = get_alias_set_entry (subset); | |
2bf105ab RK |
1223 | /* If there is an entry for the subset, enter all of its children |
1224 | (if they are not already present) as children of the SUPERSET. */ | |
ca7fd9cd | 1225 | if (subset_entry) |
2bf105ab RK |
1226 | { |
1227 | if (subset_entry->has_zero_child) | |
6e042ef4 JH |
1228 | superset_entry->has_zero_child = true; |
1229 | if (subset_entry->has_pointer) | |
1230 | superset_entry->has_pointer = true; | |
d4b60170 | 1231 | |
6e042ef4 JH |
1232 | if (subset_entry->children) |
1233 | { | |
fb5c464a | 1234 | hash_map<alias_set_hash, int>::iterator iter |
6e042ef4 JH |
1235 | = subset_entry->children->begin (); |
1236 | for (; iter != subset_entry->children->end (); ++iter) | |
1237 | superset_entry->children->put ((*iter).first, (*iter).second); | |
1238 | } | |
2bf105ab | 1239 | } |
2bf105ab | 1240 | } |
3932261a MM |
1241 | } |
1242 | ||
6b8df3e4 | 1243 | /* Record that component types of TYPE, if any, are part of SUPERSET for |
a0c33338 | 1244 | aliasing purposes. For record types, we only record component types |
b5487346 EB |
1245 | for fields that are not marked non-addressable. For array types, we |
1246 | only record the component type if it is not marked non-aliased. */ | |
a0c33338 RK |
1247 | |
1248 | void | |
6b8df3e4 | 1249 | record_component_aliases (tree type, alias_set_type superset) |
a0c33338 | 1250 | { |
a0c33338 RK |
1251 | tree field; |
1252 | ||
1253 | if (superset == 0) | |
1254 | return; | |
1255 | ||
1256 | switch (TREE_CODE (type)) | |
1257 | { | |
a0c33338 RK |
1258 | case RECORD_TYPE: |
1259 | case UNION_TYPE: | |
1260 | case QUAL_UNION_TYPE: | |
17b99c98 JH |
1261 | { |
1262 | /* LTO non-ODR type merging does not make any difference between | |
1263 | component pointer types. We may have | |
1264 | ||
1265 | struct foo {int *a;}; | |
1266 | ||
1267 | as TYPE_CANONICAL of | |
1268 | ||
1269 | struct bar {float *a;}; | |
1270 | ||
1271 | Because accesses to int * and float * do not alias, we would get | |
1272 | false negative when accessing the same memory location by | |
1273 | float ** and bar *. We thus record the canonical type as: | |
1274 | ||
1275 | struct {void *a;}; | |
1276 | ||
1277 | void * is special cased and works as a universal pointer type. | |
1278 | Accesses to it conflicts with accesses to any other pointer | |
1279 | type. */ | |
1280 | bool void_pointers = in_lto_p | |
1281 | && (!odr_type_p (type) | |
1282 | || !odr_based_tbaa_p (type)); | |
1283 | for (field = TYPE_FIELDS (type); field != 0; field = DECL_CHAIN (field)) | |
1284 | if (TREE_CODE (field) == FIELD_DECL && !DECL_NONADDRESSABLE_P (field)) | |
1285 | { | |
1286 | tree t = TREE_TYPE (field); | |
1287 | if (void_pointers) | |
1288 | { | |
1289 | /* VECTOR_TYPE and ARRAY_TYPE share the alias set with their | |
1290 | element type and that type has to be normalized to void *, | |
1291 | too, in the case it is a pointer. */ | |
1292 | while (!canonical_type_used_p (t) && !POINTER_TYPE_P (t)) | |
1293 | { | |
1294 | gcc_checking_assert (TYPE_STRUCTURAL_EQUALITY_P (t)); | |
1295 | t = TREE_TYPE (t); | |
1296 | } | |
1297 | if (POINTER_TYPE_P (t)) | |
1298 | t = ptr_type_node; | |
1299 | else if (flag_checking) | |
1300 | gcc_checking_assert (get_alias_set (t) | |
1301 | == get_alias_set (TREE_TYPE (field))); | |
1302 | } | |
1303 | ||
6b8df3e4 RB |
1304 | alias_set_type set = get_alias_set (t); |
1305 | record_alias_subset (superset, set); | |
1306 | /* If the field has alias-set zero make sure to still record | |
1307 | any componets of it. This makes sure that for | |
1308 | struct A { | |
1309 | struct B { | |
1310 | int i; | |
1311 | char c[4]; | |
1312 | } b; | |
1313 | }; | |
1314 | in C++ even though 'B' has alias-set zero because | |
1315 | TYPE_TYPELESS_STORAGE is set, 'A' has the alias-set of | |
1316 | 'int' as subset. */ | |
1317 | if (set == 0) | |
1318 | record_component_aliases (t, superset); | |
17b99c98 JH |
1319 | } |
1320 | } | |
a0c33338 RK |
1321 | break; |
1322 | ||
1d79fd2c JW |
1323 | case COMPLEX_TYPE: |
1324 | record_alias_subset (superset, get_alias_set (TREE_TYPE (type))); | |
1325 | break; | |
1326 | ||
4653cae5 RG |
1327 | /* VECTOR_TYPE and ARRAY_TYPE share the alias set with their |
1328 | element type. */ | |
1329 | ||
a0c33338 RK |
1330 | default: |
1331 | break; | |
1332 | } | |
1333 | } | |
1334 | ||
6b8df3e4 RB |
1335 | /* Record that component types of TYPE, if any, are part of that type for |
1336 | aliasing purposes. For record types, we only record component types | |
1337 | for fields that are not marked non-addressable. For array types, we | |
1338 | only record the component type if it is not marked non-aliased. */ | |
1339 | ||
1340 | void | |
1341 | record_component_aliases (tree type) | |
1342 | { | |
1343 | alias_set_type superset = get_alias_set (type); | |
1344 | record_component_aliases (type, superset); | |
1345 | } | |
1346 | ||
1347 | ||
3bdf5ad1 RK |
1348 | /* Allocate an alias set for use in storing and reading from the varargs |
1349 | spill area. */ | |
1350 | ||
4862826d | 1351 | static GTY(()) alias_set_type varargs_set = -1; |
f103e34d | 1352 | |
4862826d | 1353 | alias_set_type |
4682ae04 | 1354 | get_varargs_alias_set (void) |
3bdf5ad1 | 1355 | { |
cd3ce9b4 JM |
1356 | #if 1 |
1357 | /* We now lower VA_ARG_EXPR, and there's currently no way to attach the | |
1358 | varargs alias set to an INDIRECT_REF (FIXME!), so we can't | |
1359 | consistently use the varargs alias set for loads from the varargs | |
1360 | area. So don't use it anywhere. */ | |
1361 | return 0; | |
1362 | #else | |
f103e34d GK |
1363 | if (varargs_set == -1) |
1364 | varargs_set = new_alias_set (); | |
3bdf5ad1 | 1365 | |
f103e34d | 1366 | return varargs_set; |
cd3ce9b4 | 1367 | #endif |
3bdf5ad1 RK |
1368 | } |
1369 | ||
1370 | /* Likewise, but used for the fixed portions of the frame, e.g., register | |
1371 | save areas. */ | |
1372 | ||
4862826d | 1373 | static GTY(()) alias_set_type frame_set = -1; |
f103e34d | 1374 | |
4862826d | 1375 | alias_set_type |
4682ae04 | 1376 | get_frame_alias_set (void) |
3bdf5ad1 | 1377 | { |
f103e34d GK |
1378 | if (frame_set == -1) |
1379 | frame_set = new_alias_set (); | |
3bdf5ad1 | 1380 | |
f103e34d | 1381 | return frame_set; |
3bdf5ad1 RK |
1382 | } |
1383 | ||
9fc37b2b RS |
1384 | /* Create a new, unique base with id ID. */ |
1385 | ||
1386 | static rtx | |
1387 | unique_base_value (HOST_WIDE_INT id) | |
1388 | { | |
1389 | return gen_rtx_ADDRESS (Pmode, id); | |
1390 | } | |
1391 | ||
1392 | /* Return true if accesses based on any other base value cannot alias | |
1393 | those based on X. */ | |
1394 | ||
1395 | static bool | |
1396 | unique_base_value_p (rtx x) | |
1397 | { | |
1398 | return GET_CODE (x) == ADDRESS && GET_MODE (x) == Pmode; | |
1399 | } | |
1400 | ||
1401 | /* Return true if X is known to be a base value. */ | |
1402 | ||
1403 | static bool | |
1404 | known_base_value_p (rtx x) | |
1405 | { | |
1406 | switch (GET_CODE (x)) | |
1407 | { | |
1408 | case LABEL_REF: | |
1409 | case SYMBOL_REF: | |
1410 | return true; | |
1411 | ||
1412 | case ADDRESS: | |
1413 | /* Arguments may or may not be bases; we don't know for sure. */ | |
1414 | return GET_MODE (x) != VOIDmode; | |
1415 | ||
1416 | default: | |
1417 | return false; | |
1418 | } | |
1419 | } | |
1420 | ||
2a2c8203 JC |
1421 | /* Inside SRC, the source of a SET, find a base address. */ |
1422 | ||
9ae8ffe7 | 1423 | static rtx |
4682ae04 | 1424 | find_base_value (rtx src) |
9ae8ffe7 | 1425 | { |
713f41f9 | 1426 | unsigned int regno; |
6645d841 | 1427 | scalar_int_mode int_mode; |
0aacc8ed | 1428 | |
53451050 RS |
1429 | #if defined (FIND_BASE_TERM) |
1430 | /* Try machine-dependent ways to find the base term. */ | |
1431 | src = FIND_BASE_TERM (src); | |
1432 | #endif | |
1433 | ||
9ae8ffe7 JL |
1434 | switch (GET_CODE (src)) |
1435 | { | |
1436 | case SYMBOL_REF: | |
1437 | case LABEL_REF: | |
1438 | return src; | |
1439 | ||
1440 | case REG: | |
fb6754f0 | 1441 | regno = REGNO (src); |
d4b60170 | 1442 | /* At the start of a function, argument registers have known base |
2a2c8203 JC |
1443 | values which may be lost later. Returning an ADDRESS |
1444 | expression here allows optimization based on argument values | |
1445 | even when the argument registers are used for other purposes. */ | |
713f41f9 BS |
1446 | if (regno < FIRST_PSEUDO_REGISTER && copying_arguments) |
1447 | return new_reg_base_value[regno]; | |
73774bc7 | 1448 | |
eaf407a5 | 1449 | /* If a pseudo has a known base value, return it. Do not do this |
9b462c42 RH |
1450 | for non-fixed hard regs since it can result in a circular |
1451 | dependency chain for registers which have values at function entry. | |
eaf407a5 JL |
1452 | |
1453 | The test above is not sufficient because the scheduler may move | |
1454 | a copy out of an arg reg past the NOTE_INSN_FUNCTION_BEGIN. */ | |
9b462c42 | 1455 | if ((regno >= FIRST_PSEUDO_REGISTER || fixed_regs[regno]) |
9771b263 | 1456 | && regno < vec_safe_length (reg_base_value)) |
83bbd9b6 RH |
1457 | { |
1458 | /* If we're inside init_alias_analysis, use new_reg_base_value | |
1459 | to reduce the number of relaxation iterations. */ | |
1afdf91c | 1460 | if (new_reg_base_value && new_reg_base_value[regno] |
6fb5fa3c | 1461 | && DF_REG_DEF_COUNT (regno) == 1) |
83bbd9b6 RH |
1462 | return new_reg_base_value[regno]; |
1463 | ||
9771b263 DN |
1464 | if ((*reg_base_value)[regno]) |
1465 | return (*reg_base_value)[regno]; | |
83bbd9b6 | 1466 | } |
73774bc7 | 1467 | |
e3f049a8 | 1468 | return 0; |
9ae8ffe7 JL |
1469 | |
1470 | case MEM: | |
1471 | /* Check for an argument passed in memory. Only record in the | |
1472 | copying-arguments block; it is too hard to track changes | |
1473 | otherwise. */ | |
1474 | if (copying_arguments | |
1475 | && (XEXP (src, 0) == arg_pointer_rtx | |
1476 | || (GET_CODE (XEXP (src, 0)) == PLUS | |
1477 | && XEXP (XEXP (src, 0), 0) == arg_pointer_rtx))) | |
9fc37b2b | 1478 | return arg_base_value; |
9ae8ffe7 JL |
1479 | return 0; |
1480 | ||
1481 | case CONST: | |
1482 | src = XEXP (src, 0); | |
1483 | if (GET_CODE (src) != PLUS && GET_CODE (src) != MINUS) | |
1484 | break; | |
d4b60170 | 1485 | |
191816a3 | 1486 | /* fall through */ |
2a2c8203 | 1487 | |
9ae8ffe7 JL |
1488 | case PLUS: |
1489 | case MINUS: | |
2a2c8203 | 1490 | { |
ec907dd8 JL |
1491 | rtx temp, src_0 = XEXP (src, 0), src_1 = XEXP (src, 1); |
1492 | ||
0134bf2d DE |
1493 | /* If either operand is a REG that is a known pointer, then it |
1494 | is the base. */ | |
1495 | if (REG_P (src_0) && REG_POINTER (src_0)) | |
1496 | return find_base_value (src_0); | |
1497 | if (REG_P (src_1) && REG_POINTER (src_1)) | |
1498 | return find_base_value (src_1); | |
1499 | ||
ec907dd8 JL |
1500 | /* If either operand is a REG, then see if we already have |
1501 | a known value for it. */ | |
0134bf2d | 1502 | if (REG_P (src_0)) |
ec907dd8 JL |
1503 | { |
1504 | temp = find_base_value (src_0); | |
d4b60170 | 1505 | if (temp != 0) |
ec907dd8 JL |
1506 | src_0 = temp; |
1507 | } | |
1508 | ||
0134bf2d | 1509 | if (REG_P (src_1)) |
ec907dd8 JL |
1510 | { |
1511 | temp = find_base_value (src_1); | |
d4b60170 | 1512 | if (temp!= 0) |
ec907dd8 JL |
1513 | src_1 = temp; |
1514 | } | |
2a2c8203 | 1515 | |
0134bf2d DE |
1516 | /* If either base is named object or a special address |
1517 | (like an argument or stack reference), then use it for the | |
1518 | base term. */ | |
9fc37b2b | 1519 | if (src_0 != 0 && known_base_value_p (src_0)) |
0134bf2d DE |
1520 | return src_0; |
1521 | ||
9fc37b2b | 1522 | if (src_1 != 0 && known_base_value_p (src_1)) |
0134bf2d DE |
1523 | return src_1; |
1524 | ||
d4b60170 | 1525 | /* Guess which operand is the base address: |
ec907dd8 JL |
1526 | If either operand is a symbol, then it is the base. If |
1527 | either operand is a CONST_INT, then the other is the base. */ | |
481683e1 | 1528 | if (CONST_INT_P (src_1) || CONSTANT_P (src_0)) |
2a2c8203 | 1529 | return find_base_value (src_0); |
481683e1 | 1530 | else if (CONST_INT_P (src_0) || CONSTANT_P (src_1)) |
ec907dd8 JL |
1531 | return find_base_value (src_1); |
1532 | ||
9ae8ffe7 | 1533 | return 0; |
2a2c8203 JC |
1534 | } |
1535 | ||
1536 | case LO_SUM: | |
1537 | /* The standard form is (lo_sum reg sym) so look only at the | |
1538 | second operand. */ | |
1539 | return find_base_value (XEXP (src, 1)); | |
9ae8ffe7 JL |
1540 | |
1541 | case AND: | |
ef50b972 RB |
1542 | /* Look through aligning ANDs. And AND with zero or one with |
1543 | the LSB set isn't one (see for example PR92462). */ | |
1544 | if (CONST_INT_P (XEXP (src, 1)) | |
1545 | && INTVAL (XEXP (src, 1)) != 0 | |
1546 | && (INTVAL (XEXP (src, 1)) & 1) == 0) | |
2a2c8203 | 1547 | return find_base_value (XEXP (src, 0)); |
9ae8ffe7 JL |
1548 | return 0; |
1549 | ||
61f0131c | 1550 | case TRUNCATE: |
5932a4d4 | 1551 | /* As we do not know which address space the pointer is referring to, we can |
d4ebfa65 BE |
1552 | handle this only if the target does not support different pointer or |
1553 | address modes depending on the address space. */ | |
1554 | if (!target_default_pointer_address_modes_p ()) | |
1555 | break; | |
6645d841 RS |
1556 | if (!is_a <scalar_int_mode> (GET_MODE (src), &int_mode) |
1557 | || GET_MODE_PRECISION (int_mode) < GET_MODE_PRECISION (Pmode)) | |
61f0131c R |
1558 | break; |
1559 | /* Fall through. */ | |
9ae8ffe7 | 1560 | case HIGH: |
d288e53d DE |
1561 | case PRE_INC: |
1562 | case PRE_DEC: | |
1563 | case POST_INC: | |
1564 | case POST_DEC: | |
1565 | case PRE_MODIFY: | |
1566 | case POST_MODIFY: | |
2a2c8203 | 1567 | return find_base_value (XEXP (src, 0)); |
1d300e19 | 1568 | |
0aacc8ed RK |
1569 | case ZERO_EXTEND: |
1570 | case SIGN_EXTEND: /* used for NT/Alpha pointers */ | |
5932a4d4 | 1571 | /* As we do not know which address space the pointer is referring to, we can |
d4ebfa65 BE |
1572 | handle this only if the target does not support different pointer or |
1573 | address modes depending on the address space. */ | |
1574 | if (!target_default_pointer_address_modes_p ()) | |
1575 | break; | |
1576 | ||
0aacc8ed RK |
1577 | { |
1578 | rtx temp = find_base_value (XEXP (src, 0)); | |
1579 | ||
5ae6cd0d | 1580 | if (temp != 0 && CONSTANT_P (temp)) |
0aacc8ed | 1581 | temp = convert_memory_address (Pmode, temp); |
0aacc8ed RK |
1582 | |
1583 | return temp; | |
1584 | } | |
1585 | ||
1d300e19 KG |
1586 | default: |
1587 | break; | |
9ae8ffe7 JL |
1588 | } |
1589 | ||
1590 | return 0; | |
1591 | } | |
1592 | ||
9fc37b2b RS |
1593 | /* Called from init_alias_analysis indirectly through note_stores, |
1594 | or directly if DEST is a register with a REG_NOALIAS note attached. | |
1595 | SET is null in the latter case. */ | |
9ae8ffe7 | 1596 | |
d4b60170 | 1597 | /* While scanning insns to find base values, reg_seen[N] is nonzero if |
9ae8ffe7 | 1598 | register N has been set in this function. */ |
d630245f | 1599 | static sbitmap reg_seen; |
9ae8ffe7 | 1600 | |
2a2c8203 | 1601 | static void |
7bc980e1 | 1602 | record_set (rtx dest, const_rtx set, void *data ATTRIBUTE_UNUSED) |
9ae8ffe7 | 1603 | { |
b3694847 | 1604 | unsigned regno; |
9ae8ffe7 | 1605 | rtx src; |
c28b4e40 | 1606 | int n; |
9ae8ffe7 | 1607 | |
f8cfc6aa | 1608 | if (!REG_P (dest)) |
9ae8ffe7 JL |
1609 | return; |
1610 | ||
fb6754f0 | 1611 | regno = REGNO (dest); |
9ae8ffe7 | 1612 | |
9771b263 | 1613 | gcc_checking_assert (regno < reg_base_value->length ()); |
ac606739 | 1614 | |
dc8afb70 | 1615 | n = REG_NREGS (dest); |
c28b4e40 JW |
1616 | if (n != 1) |
1617 | { | |
1618 | while (--n >= 0) | |
1619 | { | |
d7c028c0 | 1620 | bitmap_set_bit (reg_seen, regno + n); |
c28b4e40 JW |
1621 | new_reg_base_value[regno + n] = 0; |
1622 | } | |
1623 | return; | |
1624 | } | |
1625 | ||
9ae8ffe7 JL |
1626 | if (set) |
1627 | { | |
1628 | /* A CLOBBER wipes out any old value but does not prevent a previously | |
1629 | unset register from acquiring a base address (i.e. reg_seen is not | |
1630 | set). */ | |
1631 | if (GET_CODE (set) == CLOBBER) | |
1632 | { | |
ec907dd8 | 1633 | new_reg_base_value[regno] = 0; |
9ae8ffe7 JL |
1634 | return; |
1635 | } | |
8df47bdf | 1636 | |
9ae8ffe7 JL |
1637 | src = SET_SRC (set); |
1638 | } | |
1639 | else | |
1640 | { | |
9fc37b2b | 1641 | /* There's a REG_NOALIAS note against DEST. */ |
d7c028c0 | 1642 | if (bitmap_bit_p (reg_seen, regno)) |
9ae8ffe7 | 1643 | { |
ec907dd8 | 1644 | new_reg_base_value[regno] = 0; |
9ae8ffe7 JL |
1645 | return; |
1646 | } | |
d7c028c0 | 1647 | bitmap_set_bit (reg_seen, regno); |
9fc37b2b | 1648 | new_reg_base_value[regno] = unique_base_value (unique_id++); |
9ae8ffe7 JL |
1649 | return; |
1650 | } | |
1651 | ||
5da6f168 RS |
1652 | /* If this is not the first set of REGNO, see whether the new value |
1653 | is related to the old one. There are two cases of interest: | |
1654 | ||
1655 | (1) The register might be assigned an entirely new value | |
1656 | that has the same base term as the original set. | |
1657 | ||
1658 | (2) The set might be a simple self-modification that | |
1659 | cannot change REGNO's base value. | |
1660 | ||
1661 | If neither case holds, reject the original base value as invalid. | |
1662 | Note that the following situation is not detected: | |
1663 | ||
c22cacf3 | 1664 | extern int x, y; int *p = &x; p += (&y-&x); |
5da6f168 | 1665 | |
9ae8ffe7 JL |
1666 | ANSI C does not allow computing the difference of addresses |
1667 | of distinct top level objects. */ | |
5da6f168 RS |
1668 | if (new_reg_base_value[regno] != 0 |
1669 | && find_base_value (src) != new_reg_base_value[regno]) | |
9ae8ffe7 JL |
1670 | switch (GET_CODE (src)) |
1671 | { | |
2a2c8203 | 1672 | case LO_SUM: |
9ae8ffe7 JL |
1673 | case MINUS: |
1674 | if (XEXP (src, 0) != dest && XEXP (src, 1) != dest) | |
ec907dd8 | 1675 | new_reg_base_value[regno] = 0; |
9ae8ffe7 | 1676 | break; |
61f0131c R |
1677 | case PLUS: |
1678 | /* If the value we add in the PLUS is also a valid base value, | |
1679 | this might be the actual base value, and the original value | |
1680 | an index. */ | |
1681 | { | |
1682 | rtx other = NULL_RTX; | |
1683 | ||
1684 | if (XEXP (src, 0) == dest) | |
1685 | other = XEXP (src, 1); | |
1686 | else if (XEXP (src, 1) == dest) | |
1687 | other = XEXP (src, 0); | |
1688 | ||
1689 | if (! other || find_base_value (other)) | |
1690 | new_reg_base_value[regno] = 0; | |
1691 | break; | |
1692 | } | |
9ae8ffe7 | 1693 | case AND: |
481683e1 | 1694 | if (XEXP (src, 0) != dest || !CONST_INT_P (XEXP (src, 1))) |
ec907dd8 | 1695 | new_reg_base_value[regno] = 0; |
9ae8ffe7 | 1696 | break; |
9ae8ffe7 | 1697 | default: |
ec907dd8 | 1698 | new_reg_base_value[regno] = 0; |
9ae8ffe7 JL |
1699 | break; |
1700 | } | |
1701 | /* If this is the first set of a register, record the value. */ | |
1702 | else if ((regno >= FIRST_PSEUDO_REGISTER || ! fixed_regs[regno]) | |
d7c028c0 | 1703 | && ! bitmap_bit_p (reg_seen, regno) && new_reg_base_value[regno] == 0) |
ec907dd8 | 1704 | new_reg_base_value[regno] = find_base_value (src); |
9ae8ffe7 | 1705 | |
d7c028c0 | 1706 | bitmap_set_bit (reg_seen, regno); |
9ae8ffe7 JL |
1707 | } |
1708 | ||
8fd0a474 AM |
1709 | /* Return REG_BASE_VALUE for REGNO. Selective scheduler uses this to avoid |
1710 | using hard registers with non-null REG_BASE_VALUE for renaming. */ | |
1711 | rtx | |
1712 | get_reg_base_value (unsigned int regno) | |
1713 | { | |
9771b263 | 1714 | return (*reg_base_value)[regno]; |
8fd0a474 AM |
1715 | } |
1716 | ||
bb1acb3e RH |
1717 | /* If a value is known for REGNO, return it. */ |
1718 | ||
c22cacf3 | 1719 | rtx |
bb1acb3e RH |
1720 | get_reg_known_value (unsigned int regno) |
1721 | { | |
1722 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1723 | { | |
1724 | regno -= FIRST_PSEUDO_REGISTER; | |
9771b263 DN |
1725 | if (regno < vec_safe_length (reg_known_value)) |
1726 | return (*reg_known_value)[regno]; | |
bb1acb3e RH |
1727 | } |
1728 | return NULL; | |
43fe47ca JW |
1729 | } |
1730 | ||
bb1acb3e RH |
1731 | /* Set it. */ |
1732 | ||
1733 | static void | |
1734 | set_reg_known_value (unsigned int regno, rtx val) | |
1735 | { | |
1736 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1737 | { | |
1738 | regno -= FIRST_PSEUDO_REGISTER; | |
9771b263 DN |
1739 | if (regno < vec_safe_length (reg_known_value)) |
1740 | (*reg_known_value)[regno] = val; | |
bb1acb3e RH |
1741 | } |
1742 | } | |
1743 | ||
1744 | /* Similarly for reg_known_equiv_p. */ | |
1745 | ||
1746 | bool | |
1747 | get_reg_known_equiv_p (unsigned int regno) | |
1748 | { | |
1749 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1750 | { | |
1751 | regno -= FIRST_PSEUDO_REGISTER; | |
9771b263 | 1752 | if (regno < vec_safe_length (reg_known_value)) |
d7c028c0 | 1753 | return bitmap_bit_p (reg_known_equiv_p, regno); |
bb1acb3e RH |
1754 | } |
1755 | return false; | |
1756 | } | |
1757 | ||
1758 | static void | |
1759 | set_reg_known_equiv_p (unsigned int regno, bool val) | |
1760 | { | |
1761 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1762 | { | |
1763 | regno -= FIRST_PSEUDO_REGISTER; | |
9771b263 | 1764 | if (regno < vec_safe_length (reg_known_value)) |
9ff3c7ca SB |
1765 | { |
1766 | if (val) | |
d7c028c0 | 1767 | bitmap_set_bit (reg_known_equiv_p, regno); |
9ff3c7ca | 1768 | else |
d7c028c0 | 1769 | bitmap_clear_bit (reg_known_equiv_p, regno); |
9ff3c7ca | 1770 | } |
bb1acb3e RH |
1771 | } |
1772 | } | |
1773 | ||
1774 | ||
db048faf MM |
1775 | /* Returns a canonical version of X, from the point of view alias |
1776 | analysis. (For example, if X is a MEM whose address is a register, | |
1777 | and the register has a known value (say a SYMBOL_REF), then a MEM | |
1778 | whose address is the SYMBOL_REF is returned.) */ | |
1779 | ||
1780 | rtx | |
4682ae04 | 1781 | canon_rtx (rtx x) |
9ae8ffe7 JL |
1782 | { |
1783 | /* Recursively look for equivalences. */ | |
f8cfc6aa | 1784 | if (REG_P (x) && REGNO (x) >= FIRST_PSEUDO_REGISTER) |
bb1acb3e RH |
1785 | { |
1786 | rtx t = get_reg_known_value (REGNO (x)); | |
1787 | if (t == x) | |
1788 | return x; | |
1789 | if (t) | |
1790 | return canon_rtx (t); | |
1791 | } | |
1792 | ||
1793 | if (GET_CODE (x) == PLUS) | |
9ae8ffe7 JL |
1794 | { |
1795 | rtx x0 = canon_rtx (XEXP (x, 0)); | |
1796 | rtx x1 = canon_rtx (XEXP (x, 1)); | |
1797 | ||
1798 | if (x0 != XEXP (x, 0) || x1 != XEXP (x, 1)) | |
231314e3 | 1799 | return simplify_gen_binary (PLUS, GET_MODE (x), x0, x1); |
9ae8ffe7 | 1800 | } |
d4b60170 | 1801 | |
9ae8ffe7 JL |
1802 | /* This gives us much better alias analysis when called from |
1803 | the loop optimizer. Note we want to leave the original | |
1804 | MEM alone, but need to return the canonicalized MEM with | |
1805 | all the flags with their original values. */ | |
3c0cb5de | 1806 | else if (MEM_P (x)) |
f1ec5147 | 1807 | x = replace_equiv_address_nv (x, canon_rtx (XEXP (x, 0))); |
d4b60170 | 1808 | |
9ae8ffe7 JL |
1809 | return x; |
1810 | } | |
1811 | ||
1812 | /* Return 1 if X and Y are identical-looking rtx's. | |
45183e03 | 1813 | Expect that X and Y has been already canonicalized. |
9ae8ffe7 JL |
1814 | |
1815 | We use the data in reg_known_value above to see if two registers with | |
1816 | different numbers are, in fact, equivalent. */ | |
1817 | ||
1818 | static int | |
ed7a4b4b | 1819 | rtx_equal_for_memref_p (const_rtx x, const_rtx y) |
9ae8ffe7 | 1820 | { |
b3694847 SS |
1821 | int i; |
1822 | int j; | |
1823 | enum rtx_code code; | |
1824 | const char *fmt; | |
9ae8ffe7 JL |
1825 | |
1826 | if (x == 0 && y == 0) | |
1827 | return 1; | |
1828 | if (x == 0 || y == 0) | |
1829 | return 0; | |
d4b60170 | 1830 | |
9ae8ffe7 JL |
1831 | if (x == y) |
1832 | return 1; | |
1833 | ||
1834 | code = GET_CODE (x); | |
1835 | /* Rtx's of different codes cannot be equal. */ | |
1836 | if (code != GET_CODE (y)) | |
1837 | return 0; | |
1838 | ||
1839 | /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. | |
1840 | (REG:SI x) and (REG:HI x) are NOT equivalent. */ | |
1841 | ||
1842 | if (GET_MODE (x) != GET_MODE (y)) | |
1843 | return 0; | |
1844 | ||
db048faf MM |
1845 | /* Some RTL can be compared without a recursive examination. */ |
1846 | switch (code) | |
1847 | { | |
1848 | case REG: | |
1849 | return REGNO (x) == REGNO (y); | |
1850 | ||
1851 | case LABEL_REF: | |
04a121a7 | 1852 | return label_ref_label (x) == label_ref_label (y); |
ca7fd9cd | 1853 | |
db048faf | 1854 | case SYMBOL_REF: |
6a2a3862 RS |
1855 | { |
1856 | HOST_WIDE_INT distance = 0; | |
1857 | return (compare_base_symbol_refs (x, y, &distance) == 1 | |
1858 | && distance == 0); | |
1859 | } | |
db048faf | 1860 | |
af6236c1 AO |
1861 | case ENTRY_VALUE: |
1862 | /* This is magic, don't go through canonicalization et al. */ | |
1863 | return rtx_equal_p (ENTRY_VALUE_EXP (x), ENTRY_VALUE_EXP (y)); | |
1864 | ||
40e02b4a | 1865 | case VALUE: |
d8116890 | 1866 | CASE_CONST_UNIQUE: |
807e902e | 1867 | /* Pointer equality guarantees equality for these nodes. */ |
db048faf MM |
1868 | return 0; |
1869 | ||
db048faf MM |
1870 | default: |
1871 | break; | |
1872 | } | |
9ae8ffe7 | 1873 | |
45183e03 JH |
1874 | /* canon_rtx knows how to handle plus. No need to canonicalize. */ |
1875 | if (code == PLUS) | |
9ae8ffe7 JL |
1876 | return ((rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 0)) |
1877 | && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 1))) | |
1878 | || (rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 1)) | |
1879 | && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 0)))); | |
45183e03 JH |
1880 | /* For commutative operations, the RTX match if the operand match in any |
1881 | order. Also handle the simple binary and unary cases without a loop. */ | |
ec8e098d | 1882 | if (COMMUTATIVE_P (x)) |
45183e03 JH |
1883 | { |
1884 | rtx xop0 = canon_rtx (XEXP (x, 0)); | |
1885 | rtx yop0 = canon_rtx (XEXP (y, 0)); | |
1886 | rtx yop1 = canon_rtx (XEXP (y, 1)); | |
1887 | ||
1888 | return ((rtx_equal_for_memref_p (xop0, yop0) | |
1889 | && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), yop1)) | |
1890 | || (rtx_equal_for_memref_p (xop0, yop1) | |
1891 | && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), yop0))); | |
1892 | } | |
ec8e098d | 1893 | else if (NON_COMMUTATIVE_P (x)) |
45183e03 JH |
1894 | { |
1895 | return (rtx_equal_for_memref_p (canon_rtx (XEXP (x, 0)), | |
4682ae04 | 1896 | canon_rtx (XEXP (y, 0))) |
45183e03 JH |
1897 | && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), |
1898 | canon_rtx (XEXP (y, 1)))); | |
1899 | } | |
ec8e098d | 1900 | else if (UNARY_P (x)) |
45183e03 | 1901 | return rtx_equal_for_memref_p (canon_rtx (XEXP (x, 0)), |
4682ae04 | 1902 | canon_rtx (XEXP (y, 0))); |
9ae8ffe7 JL |
1903 | |
1904 | /* Compare the elements. If any pair of corresponding elements | |
de12be17 JC |
1905 | fail to match, return 0 for the whole things. |
1906 | ||
1907 | Limit cases to types which actually appear in addresses. */ | |
9ae8ffe7 JL |
1908 | |
1909 | fmt = GET_RTX_FORMAT (code); | |
1910 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
1911 | { | |
1912 | switch (fmt[i]) | |
1913 | { | |
9ae8ffe7 JL |
1914 | case 'i': |
1915 | if (XINT (x, i) != XINT (y, i)) | |
1916 | return 0; | |
1917 | break; | |
1918 | ||
91914e56 RS |
1919 | case 'p': |
1920 | if (maybe_ne (SUBREG_BYTE (x), SUBREG_BYTE (y))) | |
1921 | return 0; | |
1922 | break; | |
1923 | ||
9ae8ffe7 JL |
1924 | case 'E': |
1925 | /* Two vectors must have the same length. */ | |
1926 | if (XVECLEN (x, i) != XVECLEN (y, i)) | |
1927 | return 0; | |
1928 | ||
1929 | /* And the corresponding elements must match. */ | |
1930 | for (j = 0; j < XVECLEN (x, i); j++) | |
45183e03 JH |
1931 | if (rtx_equal_for_memref_p (canon_rtx (XVECEXP (x, i, j)), |
1932 | canon_rtx (XVECEXP (y, i, j))) == 0) | |
9ae8ffe7 JL |
1933 | return 0; |
1934 | break; | |
1935 | ||
1936 | case 'e': | |
45183e03 JH |
1937 | if (rtx_equal_for_memref_p (canon_rtx (XEXP (x, i)), |
1938 | canon_rtx (XEXP (y, i))) == 0) | |
9ae8ffe7 JL |
1939 | return 0; |
1940 | break; | |
1941 | ||
3237ac18 AH |
1942 | /* This can happen for asm operands. */ |
1943 | case 's': | |
1944 | if (strcmp (XSTR (x, i), XSTR (y, i))) | |
1945 | return 0; | |
1946 | break; | |
1947 | ||
aee21ba9 JL |
1948 | /* This can happen for an asm which clobbers memory. */ |
1949 | case '0': | |
1950 | break; | |
1951 | ||
9ae8ffe7 JL |
1952 | /* It is believed that rtx's at this level will never |
1953 | contain anything but integers and other rtx's, | |
1954 | except for within LABEL_REFs and SYMBOL_REFs. */ | |
1955 | default: | |
298e6adc | 1956 | gcc_unreachable (); |
9ae8ffe7 JL |
1957 | } |
1958 | } | |
1959 | return 1; | |
1960 | } | |
1961 | ||
9e412ca3 | 1962 | static rtx |
6ca83833 RB |
1963 | find_base_term (rtx x, vec<std::pair<cselib_val *, |
1964 | struct elt_loc_list *> > &visited_vals) | |
9ae8ffe7 | 1965 | { |
eab5c70a | 1966 | cselib_val *val; |
6f2ffb4b AO |
1967 | struct elt_loc_list *l, *f; |
1968 | rtx ret; | |
6645d841 | 1969 | scalar_int_mode int_mode; |
eab5c70a | 1970 | |
b949ea8b JW |
1971 | #if defined (FIND_BASE_TERM) |
1972 | /* Try machine-dependent ways to find the base term. */ | |
1973 | x = FIND_BASE_TERM (x); | |
1974 | #endif | |
1975 | ||
9ae8ffe7 JL |
1976 | switch (GET_CODE (x)) |
1977 | { | |
1978 | case REG: | |
1979 | return REG_BASE_VALUE (x); | |
1980 | ||
d288e53d | 1981 | case TRUNCATE: |
5932a4d4 | 1982 | /* As we do not know which address space the pointer is referring to, we can |
d4ebfa65 BE |
1983 | handle this only if the target does not support different pointer or |
1984 | address modes depending on the address space. */ | |
1985 | if (!target_default_pointer_address_modes_p ()) | |
1986 | return 0; | |
6645d841 RS |
1987 | if (!is_a <scalar_int_mode> (GET_MODE (x), &int_mode) |
1988 | || GET_MODE_PRECISION (int_mode) < GET_MODE_PRECISION (Pmode)) | |
ca7fd9cd | 1989 | return 0; |
d288e53d | 1990 | /* Fall through. */ |
9ae8ffe7 | 1991 | case HIGH: |
6d849a2a JL |
1992 | case PRE_INC: |
1993 | case PRE_DEC: | |
1994 | case POST_INC: | |
1995 | case POST_DEC: | |
d288e53d DE |
1996 | case PRE_MODIFY: |
1997 | case POST_MODIFY: | |
6ca83833 | 1998 | return find_base_term (XEXP (x, 0), visited_vals); |
6d849a2a | 1999 | |
1abade85 RK |
2000 | case ZERO_EXTEND: |
2001 | case SIGN_EXTEND: /* Used for Alpha/NT pointers */ | |
5932a4d4 | 2002 | /* As we do not know which address space the pointer is referring to, we can |
d4ebfa65 BE |
2003 | handle this only if the target does not support different pointer or |
2004 | address modes depending on the address space. */ | |
2005 | if (!target_default_pointer_address_modes_p ()) | |
2006 | return 0; | |
2007 | ||
1abade85 | 2008 | { |
6ca83833 | 2009 | rtx temp = find_base_term (XEXP (x, 0), visited_vals); |
1abade85 | 2010 | |
5ae6cd0d | 2011 | if (temp != 0 && CONSTANT_P (temp)) |
1abade85 | 2012 | temp = convert_memory_address (Pmode, temp); |
1abade85 RK |
2013 | |
2014 | return temp; | |
2015 | } | |
2016 | ||
eab5c70a BS |
2017 | case VALUE: |
2018 | val = CSELIB_VAL_PTR (x); | |
6f2ffb4b AO |
2019 | ret = NULL_RTX; |
2020 | ||
40e02b4a | 2021 | if (!val) |
6f2ffb4b AO |
2022 | return ret; |
2023 | ||
0fe03ac3 JJ |
2024 | if (cselib_sp_based_value_p (val)) |
2025 | return static_reg_base_value[STACK_POINTER_REGNUM]; | |
2026 | ||
2e94d3ee JJ |
2027 | if (visited_vals.length () > (unsigned) param_max_find_base_term_values) |
2028 | return ret; | |
2029 | ||
6f2ffb4b | 2030 | f = val->locs; |
6ca83833 RB |
2031 | /* Reset val->locs to avoid infinite recursion. */ |
2032 | if (f) | |
2033 | visited_vals.safe_push (std::make_pair (val, f)); | |
6f2ffb4b AO |
2034 | val->locs = NULL; |
2035 | ||
2036 | for (l = f; l; l = l->next) | |
2037 | if (GET_CODE (l->loc) == VALUE | |
2038 | && CSELIB_VAL_PTR (l->loc)->locs | |
2039 | && !CSELIB_VAL_PTR (l->loc)->locs->next | |
2040 | && CSELIB_VAL_PTR (l->loc)->locs->loc == x) | |
2041 | continue; | |
6ca83833 | 2042 | else if ((ret = find_base_term (l->loc, visited_vals)) != 0) |
6f2ffb4b AO |
2043 | break; |
2044 | ||
6f2ffb4b | 2045 | return ret; |
eab5c70a | 2046 | |
023f059b JJ |
2047 | case LO_SUM: |
2048 | /* The standard form is (lo_sum reg sym) so look only at the | |
2049 | second operand. */ | |
6ca83833 | 2050 | return find_base_term (XEXP (x, 1), visited_vals); |
023f059b | 2051 | |
9ae8ffe7 JL |
2052 | case CONST: |
2053 | x = XEXP (x, 0); | |
2054 | if (GET_CODE (x) != PLUS && GET_CODE (x) != MINUS) | |
2055 | return 0; | |
938d968e | 2056 | /* Fall through. */ |
9ae8ffe7 JL |
2057 | case PLUS: |
2058 | case MINUS: | |
2059 | { | |
3c567fae JL |
2060 | rtx tmp1 = XEXP (x, 0); |
2061 | rtx tmp2 = XEXP (x, 1); | |
2062 | ||
f5143c46 | 2063 | /* This is a little bit tricky since we have to determine which of |
3c567fae JL |
2064 | the two operands represents the real base address. Otherwise this |
2065 | routine may return the index register instead of the base register. | |
2066 | ||
2067 | That may cause us to believe no aliasing was possible, when in | |
2068 | fact aliasing is possible. | |
2069 | ||
2070 | We use a few simple tests to guess the base register. Additional | |
2071 | tests can certainly be added. For example, if one of the operands | |
2072 | is a shift or multiply, then it must be the index register and the | |
2073 | other operand is the base register. */ | |
ca7fd9cd | 2074 | |
b949ea8b | 2075 | if (tmp1 == pic_offset_table_rtx && CONSTANT_P (tmp2)) |
6ca83833 | 2076 | return find_base_term (tmp2, visited_vals); |
b949ea8b | 2077 | |
31b0a960 | 2078 | /* If either operand is known to be a pointer, then prefer it |
3c567fae | 2079 | to determine the base term. */ |
3502dc9c | 2080 | if (REG_P (tmp1) && REG_POINTER (tmp1)) |
31b0a960 RB |
2081 | ; |
2082 | else if (REG_P (tmp2) && REG_POINTER (tmp2)) | |
a7c75343 JJ |
2083 | std::swap (tmp1, tmp2); |
2084 | /* If second argument is constant which has base term, prefer it | |
2085 | over variable tmp1. See PR64025. */ | |
2086 | else if (CONSTANT_P (tmp2) && !CONST_INT_P (tmp2)) | |
2087 | std::swap (tmp1, tmp2); | |
3c567fae | 2088 | |
31b0a960 RB |
2089 | /* Go ahead and find the base term for both operands. If either base |
2090 | term is from a pointer or is a named object or a special address | |
3c567fae JL |
2091 | (like an argument or stack reference), then use it for the |
2092 | base term. */ | |
6ca83833 | 2093 | rtx base = find_base_term (tmp1, visited_vals); |
481be1c4 | 2094 | if (base != NULL_RTX |
31b0a960 | 2095 | && ((REG_P (tmp1) && REG_POINTER (tmp1)) |
481be1c4 RB |
2096 | || known_base_value_p (base))) |
2097 | return base; | |
6ca83833 | 2098 | base = find_base_term (tmp2, visited_vals); |
481be1c4 | 2099 | if (base != NULL_RTX |
31b0a960 | 2100 | && ((REG_P (tmp2) && REG_POINTER (tmp2)) |
481be1c4 RB |
2101 | || known_base_value_p (base))) |
2102 | return base; | |
3c567fae JL |
2103 | |
2104 | /* We could not determine which of the two operands was the | |
2105 | base register and which was the index. So we can determine | |
2106 | nothing from the base alias check. */ | |
2107 | return 0; | |
9ae8ffe7 JL |
2108 | } |
2109 | ||
2110 | case AND: | |
ef50b972 RB |
2111 | /* Look through aligning ANDs. And AND with zero or one with |
2112 | the LSB set isn't one (see for example PR92462). */ | |
2113 | if (CONST_INT_P (XEXP (x, 1)) | |
2114 | && INTVAL (XEXP (x, 1)) != 0 | |
2115 | && (INTVAL (XEXP (x, 1)) & 1) == 0) | |
6ca83833 | 2116 | return find_base_term (XEXP (x, 0), visited_vals); |
9ae8ffe7 JL |
2117 | return 0; |
2118 | ||
2119 | case SYMBOL_REF: | |
2120 | case LABEL_REF: | |
2121 | return x; | |
2122 | ||
2123 | default: | |
2124 | return 0; | |
2125 | } | |
2126 | } | |
2127 | ||
6ca83833 RB |
2128 | /* Wrapper around the worker above which removes locs from visited VALUEs |
2129 | to avoid visiting them multiple times. We unwind that changes here. */ | |
2130 | ||
2131 | static rtx | |
2132 | find_base_term (rtx x) | |
2133 | { | |
2134 | auto_vec<std::pair<cselib_val *, struct elt_loc_list *>, 32> visited_vals; | |
2135 | rtx res = find_base_term (x, visited_vals); | |
2136 | for (unsigned i = 0; i < visited_vals.length (); ++i) | |
2137 | visited_vals[i].first->locs = visited_vals[i].second; | |
2138 | return res; | |
2139 | } | |
2140 | ||
9e412ca3 RS |
2141 | /* Return true if accesses to address X may alias accesses based |
2142 | on the stack pointer. */ | |
2143 | ||
2144 | bool | |
2145 | may_be_sp_based_p (rtx x) | |
2146 | { | |
2147 | rtx base = find_base_term (x); | |
2148 | return !base || base == static_reg_base_value[STACK_POINTER_REGNUM]; | |
2149 | } | |
2150 | ||
54363f8a | 2151 | /* BASE1 and BASE2 are decls. Return 1 if they refer to same object, 0 |
67914693 | 2152 | if they refer to different objects and -1 if we cannot decide. */ |
54363f8a JH |
2153 | |
2154 | int | |
2155 | compare_base_decls (tree base1, tree base2) | |
2156 | { | |
2157 | int ret; | |
2158 | gcc_checking_assert (DECL_P (base1) && DECL_P (base2)); | |
2159 | if (base1 == base2) | |
2160 | return 1; | |
2161 | ||
bed3fd46 | 2162 | /* If we have two register decls with register specification we |
816c4ba2 | 2163 | cannot decide unless their assembler names are the same. */ |
371f0b99 RB |
2164 | if (VAR_P (base1) |
2165 | && VAR_P (base2) | |
2166 | && DECL_HARD_REGISTER (base1) | |
2167 | && DECL_HARD_REGISTER (base2) | |
bed3fd46 RB |
2168 | && DECL_ASSEMBLER_NAME_SET_P (base1) |
2169 | && DECL_ASSEMBLER_NAME_SET_P (base2)) | |
2170 | { | |
816c4ba2 | 2171 | if (DECL_ASSEMBLER_NAME_RAW (base1) == DECL_ASSEMBLER_NAME_RAW (base2)) |
bed3fd46 RB |
2172 | return 1; |
2173 | return -1; | |
2174 | } | |
2175 | ||
54363f8a JH |
2176 | /* Declarations of non-automatic variables may have aliases. All other |
2177 | decls are unique. */ | |
7ec4f343 NS |
2178 | if (!decl_in_symtab_p (base1) |
2179 | || !decl_in_symtab_p (base2)) | |
54363f8a | 2180 | return 0; |
7ec4f343 | 2181 | |
929710d9 NS |
2182 | /* Don't cause symbols to be inserted by the act of checking. */ |
2183 | symtab_node *node1 = symtab_node::get (base1); | |
2184 | if (!node1) | |
2185 | return 0; | |
2186 | symtab_node *node2 = symtab_node::get (base2); | |
2187 | if (!node2) | |
2188 | return 0; | |
2189 | ||
2190 | ret = node1->equal_address_to (node2, true); | |
54363f8a JH |
2191 | return ret; |
2192 | } | |
2193 | ||
6a2a3862 RS |
2194 | /* Compare SYMBOL_REFs X_BASE and Y_BASE. |
2195 | ||
2196 | - Return 1 if Y_BASE - X_BASE is constant, adding that constant | |
2197 | to *DISTANCE if DISTANCE is nonnull. | |
2198 | ||
2199 | - Return 0 if no accesses based on X_BASE can alias Y_BASE. | |
2200 | ||
2201 | - Return -1 if one of the two results applies, but we can't tell | |
2202 | which at compile time. Update DISTANCE in the same way as | |
2203 | for a return value of 1, for the case in which that holds. */ | |
73e48cb3 JH |
2204 | |
2205 | static int | |
6a2a3862 RS |
2206 | compare_base_symbol_refs (const_rtx x_base, const_rtx y_base, |
2207 | HOST_WIDE_INT *distance) | |
73e48cb3 JH |
2208 | { |
2209 | tree x_decl = SYMBOL_REF_DECL (x_base); | |
2210 | tree y_decl = SYMBOL_REF_DECL (y_base); | |
2211 | bool binds_def = true; | |
d34cdec5 | 2212 | bool swap = false; |
73e48cb3 JH |
2213 | |
2214 | if (XSTR (x_base, 0) == XSTR (y_base, 0)) | |
2215 | return 1; | |
2216 | if (x_decl && y_decl) | |
2217 | return compare_base_decls (x_decl, y_decl); | |
2218 | if (x_decl || y_decl) | |
2219 | { | |
2220 | if (!x_decl) | |
2221 | { | |
d34cdec5 | 2222 | swap = true; |
73e48cb3 JH |
2223 | std::swap (x_decl, y_decl); |
2224 | std::swap (x_base, y_base); | |
2225 | } | |
6a2a3862 RS |
2226 | /* We handle specially only section anchors. Other symbols are |
2227 | either equal (via aliasing) or refer to different objects. */ | |
73e48cb3 JH |
2228 | if (!SYMBOL_REF_HAS_BLOCK_INFO_P (y_base)) |
2229 | return -1; | |
2230 | /* Anchors contains static VAR_DECLs and CONST_DECLs. We are safe | |
2231 | to ignore CONST_DECLs because they are readonly. */ | |
8813a647 | 2232 | if (!VAR_P (x_decl) |
73e48cb3 JH |
2233 | || (!TREE_STATIC (x_decl) && !TREE_PUBLIC (x_decl))) |
2234 | return 0; | |
2235 | ||
2236 | symtab_node *x_node = symtab_node::get_create (x_decl) | |
2237 | ->ultimate_alias_target (); | |
67914693 | 2238 | /* External variable cannot be in section anchor. */ |
73e48cb3 JH |
2239 | if (!x_node->definition) |
2240 | return 0; | |
2241 | x_base = XEXP (DECL_RTL (x_node->decl), 0); | |
2242 | /* If not in anchor, we can disambiguate. */ | |
2243 | if (!SYMBOL_REF_HAS_BLOCK_INFO_P (x_base)) | |
2244 | return 0; | |
2245 | ||
2246 | /* We have an alias of anchored variable. If it can be interposed; | |
2247 | we must assume it may or may not alias its anchor. */ | |
2248 | binds_def = decl_binds_to_current_def_p (x_decl); | |
2249 | } | |
2250 | /* If we have variable in section anchor, we can compare by offset. */ | |
2251 | if (SYMBOL_REF_HAS_BLOCK_INFO_P (x_base) | |
2252 | && SYMBOL_REF_HAS_BLOCK_INFO_P (y_base)) | |
2253 | { | |
2254 | if (SYMBOL_REF_BLOCK (x_base) != SYMBOL_REF_BLOCK (y_base)) | |
2255 | return 0; | |
6a2a3862 | 2256 | if (distance) |
d34cdec5 AV |
2257 | *distance += (swap ? -1 : 1) * (SYMBOL_REF_BLOCK_OFFSET (y_base) |
2258 | - SYMBOL_REF_BLOCK_OFFSET (x_base)); | |
6a2a3862 | 2259 | return binds_def ? 1 : -1; |
73e48cb3 | 2260 | } |
6a2a3862 RS |
2261 | /* Either the symbols are equal (via aliasing) or they refer to |
2262 | different objects. */ | |
73e48cb3 JH |
2263 | return -1; |
2264 | } | |
2265 | ||
9ae8ffe7 JL |
2266 | /* Return 0 if the addresses X and Y are known to point to different |
2267 | objects, 1 if they might be pointers to the same object. */ | |
2268 | ||
2269 | static int | |
31b0a960 | 2270 | base_alias_check (rtx x, rtx x_base, rtx y, rtx y_base, |
ef4bddc2 | 2271 | machine_mode x_mode, machine_mode y_mode) |
9ae8ffe7 | 2272 | { |
1c72c7f6 JC |
2273 | /* If the address itself has no known base see if a known equivalent |
2274 | value has one. If either address still has no known base, nothing | |
2275 | is known about aliasing. */ | |
2276 | if (x_base == 0) | |
2277 | { | |
2278 | rtx x_c; | |
d4b60170 | 2279 | |
1c72c7f6 JC |
2280 | if (! flag_expensive_optimizations || (x_c = canon_rtx (x)) == x) |
2281 | return 1; | |
d4b60170 | 2282 | |
1c72c7f6 JC |
2283 | x_base = find_base_term (x_c); |
2284 | if (x_base == 0) | |
2285 | return 1; | |
2286 | } | |
9ae8ffe7 | 2287 | |
1c72c7f6 JC |
2288 | if (y_base == 0) |
2289 | { | |
2290 | rtx y_c; | |
2291 | if (! flag_expensive_optimizations || (y_c = canon_rtx (y)) == y) | |
2292 | return 1; | |
d4b60170 | 2293 | |
1c72c7f6 JC |
2294 | y_base = find_base_term (y_c); |
2295 | if (y_base == 0) | |
2296 | return 1; | |
2297 | } | |
2298 | ||
2299 | /* If the base addresses are equal nothing is known about aliasing. */ | |
2300 | if (rtx_equal_p (x_base, y_base)) | |
9ae8ffe7 JL |
2301 | return 1; |
2302 | ||
435da628 UB |
2303 | /* The base addresses are different expressions. If they are not accessed |
2304 | via AND, there is no conflict. We can bring knowledge of object | |
2305 | alignment into play here. For example, on alpha, "char a, b;" can | |
5764ee3c | 2306 | alias one another, though "char a; long b;" cannot. AND addresses may |
435da628 UB |
2307 | implicitly alias surrounding objects; i.e. unaligned access in DImode |
2308 | via AND address can alias all surrounding object types except those | |
2309 | with aligment 8 or higher. */ | |
2310 | if (GET_CODE (x) == AND && GET_CODE (y) == AND) | |
2311 | return 1; | |
2312 | if (GET_CODE (x) == AND | |
481683e1 | 2313 | && (!CONST_INT_P (XEXP (x, 1)) |
435da628 UB |
2314 | || (int) GET_MODE_UNIT_SIZE (y_mode) < -INTVAL (XEXP (x, 1)))) |
2315 | return 1; | |
2316 | if (GET_CODE (y) == AND | |
481683e1 | 2317 | && (!CONST_INT_P (XEXP (y, 1)) |
435da628 UB |
2318 | || (int) GET_MODE_UNIT_SIZE (x_mode) < -INTVAL (XEXP (y, 1)))) |
2319 | return 1; | |
2320 | ||
73e48cb3 | 2321 | /* Differing symbols not accessed via AND never alias. */ |
3a28db46 | 2322 | if (GET_CODE (x_base) == SYMBOL_REF && GET_CODE (y_base) == SYMBOL_REF) |
73e48cb3 | 2323 | return compare_base_symbol_refs (x_base, y_base) != 0; |
3a28db46 | 2324 | |
9ae8ffe7 | 2325 | if (GET_CODE (x_base) != ADDRESS && GET_CODE (y_base) != ADDRESS) |
435da628 | 2326 | return 0; |
9ae8ffe7 | 2327 | |
9fc37b2b | 2328 | if (unique_base_value_p (x_base) || unique_base_value_p (y_base)) |
9ae8ffe7 JL |
2329 | return 0; |
2330 | ||
0d3c82d6 | 2331 | return 1; |
9ae8ffe7 JL |
2332 | } |
2333 | ||
a5628378 | 2334 | /* Return TRUE if EXPR refers to a VALUE whose uid is greater than |
c779924e | 2335 | (or equal to) that of V. */ |
a5628378 AO |
2336 | |
2337 | static bool | |
403837b4 | 2338 | refs_newer_value_p (const_rtx expr, rtx v) |
a5628378 AO |
2339 | { |
2340 | int minuid = CSELIB_VAL_PTR (v)->uid; | |
403837b4 RS |
2341 | subrtx_iterator::array_type array; |
2342 | FOR_EACH_SUBRTX (iter, array, expr, NONCONST) | |
c779924e | 2343 | if (GET_CODE (*iter) == VALUE && CSELIB_VAL_PTR (*iter)->uid >= minuid) |
403837b4 RS |
2344 | return true; |
2345 | return false; | |
a5628378 AO |
2346 | } |
2347 | ||
eab5c70a | 2348 | /* Convert the address X into something we can use. This is done by returning |
569efc34 JJ |
2349 | it unchanged unless it is a VALUE or VALUE +/- constant; for VALUE |
2350 | we call cselib to get a more useful rtx. */ | |
3bdf5ad1 | 2351 | |
a13d4ebf | 2352 | rtx |
4682ae04 | 2353 | get_addr (rtx x) |
eab5c70a BS |
2354 | { |
2355 | cselib_val *v; | |
2356 | struct elt_loc_list *l; | |
2357 | ||
2358 | if (GET_CODE (x) != VALUE) | |
569efc34 JJ |
2359 | { |
2360 | if ((GET_CODE (x) == PLUS || GET_CODE (x) == MINUS) | |
2361 | && GET_CODE (XEXP (x, 0)) == VALUE | |
2362 | && CONST_SCALAR_INT_P (XEXP (x, 1))) | |
2363 | { | |
2364 | rtx op0 = get_addr (XEXP (x, 0)); | |
2365 | if (op0 != XEXP (x, 0)) | |
2366 | { | |
5284e559 | 2367 | poly_int64 c; |
569efc34 | 2368 | if (GET_CODE (x) == PLUS |
5284e559 RS |
2369 | && poly_int_rtx_p (XEXP (x, 1), &c)) |
2370 | return plus_constant (GET_MODE (x), op0, c); | |
569efc34 JJ |
2371 | return simplify_gen_binary (GET_CODE (x), GET_MODE (x), |
2372 | op0, XEXP (x, 1)); | |
2373 | } | |
2374 | } | |
2375 | return x; | |
2376 | } | |
eab5c70a | 2377 | v = CSELIB_VAL_PTR (x); |
40e02b4a JH |
2378 | if (v) |
2379 | { | |
0f68ba3e AO |
2380 | bool have_equivs = cselib_have_permanent_equivalences (); |
2381 | if (have_equivs) | |
2382 | v = canonical_cselib_val (v); | |
40e02b4a JH |
2383 | for (l = v->locs; l; l = l->next) |
2384 | if (CONSTANT_P (l->loc)) | |
2385 | return l->loc; | |
2386 | for (l = v->locs; l; l = l->next) | |
0f68ba3e AO |
2387 | if (!REG_P (l->loc) && !MEM_P (l->loc) |
2388 | /* Avoid infinite recursion when potentially dealing with | |
2389 | var-tracking artificial equivalences, by skipping the | |
2390 | equivalences themselves, and not choosing expressions | |
2391 | that refer to newer VALUEs. */ | |
2392 | && (!have_equivs | |
2393 | || (GET_CODE (l->loc) != VALUE | |
2394 | && !refs_newer_value_p (l->loc, x)))) | |
a5628378 | 2395 | return l->loc; |
0f68ba3e AO |
2396 | if (have_equivs) |
2397 | { | |
2398 | for (l = v->locs; l; l = l->next) | |
2399 | if (REG_P (l->loc) | |
2400 | || (GET_CODE (l->loc) != VALUE | |
2401 | && !refs_newer_value_p (l->loc, x))) | |
2402 | return l->loc; | |
2403 | /* Return the canonical value. */ | |
2404 | return v->val_rtx; | |
2405 | } | |
2406 | if (v->locs) | |
2407 | return v->locs->loc; | |
40e02b4a | 2408 | } |
eab5c70a BS |
2409 | return x; |
2410 | } | |
2411 | ||
39cec1ac MH |
2412 | /* Return the address of the (N_REFS + 1)th memory reference to ADDR |
2413 | where SIZE is the size in bytes of the memory reference. If ADDR | |
2414 | is not modified by the memory reference then ADDR is returned. */ | |
2415 | ||
04e2b4d3 | 2416 | static rtx |
9f61be58 | 2417 | addr_side_effect_eval (rtx addr, poly_int64 size, int n_refs) |
39cec1ac | 2418 | { |
9f61be58 | 2419 | poly_int64 offset = 0; |
ca7fd9cd | 2420 | |
39cec1ac MH |
2421 | switch (GET_CODE (addr)) |
2422 | { | |
2423 | case PRE_INC: | |
2424 | offset = (n_refs + 1) * size; | |
2425 | break; | |
2426 | case PRE_DEC: | |
2427 | offset = -(n_refs + 1) * size; | |
2428 | break; | |
2429 | case POST_INC: | |
2430 | offset = n_refs * size; | |
2431 | break; | |
2432 | case POST_DEC: | |
2433 | offset = -n_refs * size; | |
2434 | break; | |
2435 | ||
2436 | default: | |
2437 | return addr; | |
2438 | } | |
ca7fd9cd | 2439 | |
9f61be58 | 2440 | addr = plus_constant (GET_MODE (addr), XEXP (addr, 0), offset); |
45183e03 | 2441 | addr = canon_rtx (addr); |
39cec1ac MH |
2442 | |
2443 | return addr; | |
2444 | } | |
2445 | ||
3aa03517 AO |
2446 | /* Return TRUE if an object X sized at XSIZE bytes and another object |
2447 | Y sized at YSIZE bytes, starting C bytes after X, may overlap. If | |
2448 | any of the sizes is zero, assume an overlap, otherwise use the | |
2449 | absolute value of the sizes as the actual sizes. */ | |
2450 | ||
2451 | static inline bool | |
d05d7551 | 2452 | offset_overlap_p (poly_int64 c, poly_int64 xsize, poly_int64 ysize) |
3aa03517 | 2453 | { |
d05d7551 RS |
2454 | if (known_eq (xsize, 0) || known_eq (ysize, 0)) |
2455 | return true; | |
2456 | ||
2457 | if (maybe_ge (c, 0)) | |
2458 | return maybe_gt (maybe_lt (xsize, 0) ? -xsize : xsize, c); | |
2459 | else | |
2460 | return maybe_gt (maybe_lt (ysize, 0) ? -ysize : ysize, -c); | |
3aa03517 AO |
2461 | } |
2462 | ||
f47e08d9 RG |
2463 | /* Return one if X and Y (memory addresses) reference the |
2464 | same location in memory or if the references overlap. | |
2465 | Return zero if they do not overlap, else return | |
2466 | minus one in which case they still might reference the same location. | |
2467 | ||
2468 | C is an offset accumulator. When | |
9ae8ffe7 JL |
2469 | C is nonzero, we are testing aliases between X and Y + C. |
2470 | XSIZE is the size in bytes of the X reference, | |
2471 | similarly YSIZE is the size in bytes for Y. | |
45183e03 | 2472 | Expect that canon_rtx has been already called for X and Y. |
9ae8ffe7 JL |
2473 | |
2474 | If XSIZE or YSIZE is zero, we do not know the amount of memory being | |
2475 | referenced (the reference was BLKmode), so make the most pessimistic | |
2476 | assumptions. | |
2477 | ||
c02f035f RH |
2478 | If XSIZE or YSIZE is negative, we may access memory outside the object |
2479 | being referenced as a side effect. This can happen when using AND to | |
2480 | align memory references, as is done on the Alpha. | |
2481 | ||
9ae8ffe7 | 2482 | Nice to notice that varying addresses cannot conflict with fp if no |
f47e08d9 RG |
2483 | local variables had their addresses taken, but that's too hard now. |
2484 | ||
2485 | ??? Contrary to the tree alias oracle this does not return | |
2486 | one for X + non-constant and Y + non-constant when X and Y are equal. | |
2487 | If that is fixed the TBAA hack for union type-punning can be removed. */ | |
9ae8ffe7 | 2488 | |
9ae8ffe7 | 2489 | static int |
9f61be58 RS |
2490 | memrefs_conflict_p (poly_int64 xsize, rtx x, poly_int64 ysize, rtx y, |
2491 | poly_int64 c) | |
9ae8ffe7 | 2492 | { |
eab5c70a | 2493 | if (GET_CODE (x) == VALUE) |
5312b066 JJ |
2494 | { |
2495 | if (REG_P (y)) | |
2496 | { | |
24f8d71e JJ |
2497 | struct elt_loc_list *l = NULL; |
2498 | if (CSELIB_VAL_PTR (x)) | |
a5628378 AO |
2499 | for (l = canonical_cselib_val (CSELIB_VAL_PTR (x))->locs; |
2500 | l; l = l->next) | |
24f8d71e JJ |
2501 | if (REG_P (l->loc) && rtx_equal_for_memref_p (l->loc, y)) |
2502 | break; | |
5312b066 JJ |
2503 | if (l) |
2504 | x = y; | |
2505 | else | |
2506 | x = get_addr (x); | |
2507 | } | |
2508 | /* Don't call get_addr if y is the same VALUE. */ | |
2509 | else if (x != y) | |
2510 | x = get_addr (x); | |
2511 | } | |
eab5c70a | 2512 | if (GET_CODE (y) == VALUE) |
5312b066 JJ |
2513 | { |
2514 | if (REG_P (x)) | |
2515 | { | |
24f8d71e JJ |
2516 | struct elt_loc_list *l = NULL; |
2517 | if (CSELIB_VAL_PTR (y)) | |
a5628378 AO |
2518 | for (l = canonical_cselib_val (CSELIB_VAL_PTR (y))->locs; |
2519 | l; l = l->next) | |
24f8d71e JJ |
2520 | if (REG_P (l->loc) && rtx_equal_for_memref_p (l->loc, x)) |
2521 | break; | |
5312b066 JJ |
2522 | if (l) |
2523 | y = x; | |
2524 | else | |
2525 | y = get_addr (y); | |
2526 | } | |
2527 | /* Don't call get_addr if x is the same VALUE. */ | |
2528 | else if (y != x) | |
2529 | y = get_addr (y); | |
2530 | } | |
9ae8ffe7 JL |
2531 | if (GET_CODE (x) == HIGH) |
2532 | x = XEXP (x, 0); | |
2533 | else if (GET_CODE (x) == LO_SUM) | |
2534 | x = XEXP (x, 1); | |
2535 | else | |
9f61be58 | 2536 | x = addr_side_effect_eval (x, maybe_lt (xsize, 0) ? -xsize : xsize, 0); |
9ae8ffe7 JL |
2537 | if (GET_CODE (y) == HIGH) |
2538 | y = XEXP (y, 0); | |
2539 | else if (GET_CODE (y) == LO_SUM) | |
2540 | y = XEXP (y, 1); | |
2541 | else | |
9f61be58 | 2542 | y = addr_side_effect_eval (y, maybe_lt (ysize, 0) ? -ysize : ysize, 0); |
9ae8ffe7 | 2543 | |
54363f8a JH |
2544 | if (GET_CODE (x) == SYMBOL_REF && GET_CODE (y) == SYMBOL_REF) |
2545 | { | |
6a2a3862 RS |
2546 | HOST_WIDE_INT distance = 0; |
2547 | int cmp = compare_base_symbol_refs (x, y, &distance); | |
54363f8a JH |
2548 | |
2549 | /* If both decls are the same, decide by offsets. */ | |
2550 | if (cmp == 1) | |
6a2a3862 | 2551 | return offset_overlap_p (c + distance, xsize, ysize); |
3a28db46 UB |
2552 | /* Assume a potential overlap for symbolic addresses that went |
2553 | through alignment adjustments (i.e., that have negative | |
2554 | sizes), because we can't know how far they are from each | |
2555 | other. */ | |
9f61be58 | 2556 | if (maybe_lt (xsize, 0) || maybe_lt (ysize, 0)) |
3a28db46 | 2557 | return -1; |
54363f8a JH |
2558 | /* If decls are different or we know by offsets that there is no overlap, |
2559 | we win. */ | |
6a2a3862 | 2560 | if (!cmp || !offset_overlap_p (c + distance, xsize, ysize)) |
54363f8a JH |
2561 | return 0; |
2562 | /* Decls may or may not be different and offsets overlap....*/ | |
2563 | return -1; | |
2564 | } | |
2565 | else if (rtx_equal_for_memref_p (x, y)) | |
9ae8ffe7 | 2566 | { |
3aa03517 | 2567 | return offset_overlap_p (c, xsize, ysize); |
9ae8ffe7 JL |
2568 | } |
2569 | ||
6e73e666 JC |
2570 | /* This code used to check for conflicts involving stack references and |
2571 | globals but the base address alias code now handles these cases. */ | |
9ae8ffe7 JL |
2572 | |
2573 | if (GET_CODE (x) == PLUS) | |
2574 | { | |
2575 | /* The fact that X is canonicalized means that this | |
2576 | PLUS rtx is canonicalized. */ | |
2577 | rtx x0 = XEXP (x, 0); | |
2578 | rtx x1 = XEXP (x, 1); | |
2579 | ||
2d88904a AO |
2580 | /* However, VALUEs might end up in different positions even in |
2581 | canonical PLUSes. Comparing their addresses is enough. */ | |
2582 | if (x0 == y) | |
2583 | return memrefs_conflict_p (xsize, x1, ysize, const0_rtx, c); | |
2584 | else if (x1 == y) | |
2585 | return memrefs_conflict_p (xsize, x0, ysize, const0_rtx, c); | |
2586 | ||
9f61be58 | 2587 | poly_int64 cx1, cy1; |
9ae8ffe7 JL |
2588 | if (GET_CODE (y) == PLUS) |
2589 | { | |
2590 | /* The fact that Y is canonicalized means that this | |
2591 | PLUS rtx is canonicalized. */ | |
2592 | rtx y0 = XEXP (y, 0); | |
2593 | rtx y1 = XEXP (y, 1); | |
2594 | ||
2d88904a AO |
2595 | if (x0 == y1) |
2596 | return memrefs_conflict_p (xsize, x1, ysize, y0, c); | |
2597 | if (x1 == y0) | |
2598 | return memrefs_conflict_p (xsize, x0, ysize, y1, c); | |
2599 | ||
9ae8ffe7 JL |
2600 | if (rtx_equal_for_memref_p (x1, y1)) |
2601 | return memrefs_conflict_p (xsize, x0, ysize, y0, c); | |
2602 | if (rtx_equal_for_memref_p (x0, y0)) | |
2603 | return memrefs_conflict_p (xsize, x1, ysize, y1, c); | |
9f61be58 | 2604 | if (poly_int_rtx_p (x1, &cx1)) |
63be02db | 2605 | { |
9f61be58 | 2606 | if (poly_int_rtx_p (y1, &cy1)) |
63be02db | 2607 | return memrefs_conflict_p (xsize, x0, ysize, y0, |
9f61be58 | 2608 | c - cx1 + cy1); |
63be02db | 2609 | else |
9f61be58 | 2610 | return memrefs_conflict_p (xsize, x0, ysize, y, c - cx1); |
63be02db | 2611 | } |
9f61be58 RS |
2612 | else if (poly_int_rtx_p (y1, &cy1)) |
2613 | return memrefs_conflict_p (xsize, x, ysize, y0, c + cy1); | |
9ae8ffe7 | 2614 | |
f47e08d9 | 2615 | return -1; |
9ae8ffe7 | 2616 | } |
9f61be58 RS |
2617 | else if (poly_int_rtx_p (x1, &cx1)) |
2618 | return memrefs_conflict_p (xsize, x0, ysize, y, c - cx1); | |
9ae8ffe7 JL |
2619 | } |
2620 | else if (GET_CODE (y) == PLUS) | |
2621 | { | |
2622 | /* The fact that Y is canonicalized means that this | |
2623 | PLUS rtx is canonicalized. */ | |
2624 | rtx y0 = XEXP (y, 0); | |
2625 | rtx y1 = XEXP (y, 1); | |
2626 | ||
2d88904a AO |
2627 | if (x == y0) |
2628 | return memrefs_conflict_p (xsize, const0_rtx, ysize, y1, c); | |
2629 | if (x == y1) | |
2630 | return memrefs_conflict_p (xsize, const0_rtx, ysize, y0, c); | |
2631 | ||
9f61be58 RS |
2632 | poly_int64 cy1; |
2633 | if (poly_int_rtx_p (y1, &cy1)) | |
2634 | return memrefs_conflict_p (xsize, x, ysize, y0, c + cy1); | |
9ae8ffe7 | 2635 | else |
f47e08d9 | 2636 | return -1; |
9ae8ffe7 JL |
2637 | } |
2638 | ||
2639 | if (GET_CODE (x) == GET_CODE (y)) | |
2640 | switch (GET_CODE (x)) | |
2641 | { | |
2642 | case MULT: | |
2643 | { | |
2644 | /* Handle cases where we expect the second operands to be the | |
2645 | same, and check only whether the first operand would conflict | |
2646 | or not. */ | |
2647 | rtx x0, y0; | |
2648 | rtx x1 = canon_rtx (XEXP (x, 1)); | |
2649 | rtx y1 = canon_rtx (XEXP (y, 1)); | |
2650 | if (! rtx_equal_for_memref_p (x1, y1)) | |
f47e08d9 | 2651 | return -1; |
9ae8ffe7 JL |
2652 | x0 = canon_rtx (XEXP (x, 0)); |
2653 | y0 = canon_rtx (XEXP (y, 0)); | |
2654 | if (rtx_equal_for_memref_p (x0, y0)) | |
3aa03517 | 2655 | return offset_overlap_p (c, xsize, ysize); |
9ae8ffe7 JL |
2656 | |
2657 | /* Can't properly adjust our sizes. */ | |
5284e559 RS |
2658 | poly_int64 c1; |
2659 | if (!poly_int_rtx_p (x1, &c1) | |
2660 | || !can_div_trunc_p (xsize, c1, &xsize) | |
2661 | || !can_div_trunc_p (ysize, c1, &ysize) | |
2662 | || !can_div_trunc_p (c, c1, &c)) | |
f47e08d9 | 2663 | return -1; |
9ae8ffe7 JL |
2664 | return memrefs_conflict_p (xsize, x0, ysize, y0, c); |
2665 | } | |
1d300e19 KG |
2666 | |
2667 | default: | |
2668 | break; | |
9ae8ffe7 JL |
2669 | } |
2670 | ||
a9bf4fe2 AO |
2671 | /* Deal with alignment ANDs by adjusting offset and size so as to |
2672 | cover the maximum range, without taking any previously known | |
5147bf6a AO |
2673 | alignment into account. Make a size negative after such an |
2674 | adjustments, so that, if we end up with e.g. two SYMBOL_REFs, we | |
2675 | assume a potential overlap, because they may end up in contiguous | |
2676 | memory locations and the stricter-alignment access may span over | |
2677 | part of both. */ | |
481683e1 | 2678 | if (GET_CODE (x) == AND && CONST_INT_P (XEXP (x, 1))) |
56ee9281 | 2679 | { |
a9bf4fe2 AO |
2680 | HOST_WIDE_INT sc = INTVAL (XEXP (x, 1)); |
2681 | unsigned HOST_WIDE_INT uc = sc; | |
146ec50f | 2682 | if (sc < 0 && pow2_or_zerop (-uc)) |
a9bf4fe2 | 2683 | { |
9f61be58 | 2684 | if (maybe_gt (xsize, 0)) |
5147bf6a | 2685 | xsize = -xsize; |
9f61be58 | 2686 | if (maybe_ne (xsize, 0)) |
3aa03517 | 2687 | xsize += sc + 1; |
fe8fb1c4 | 2688 | c -= sc + 1; |
a9bf4fe2 AO |
2689 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), |
2690 | ysize, y, c); | |
2691 | } | |
56ee9281 | 2692 | } |
481683e1 | 2693 | if (GET_CODE (y) == AND && CONST_INT_P (XEXP (y, 1))) |
c02f035f | 2694 | { |
a9bf4fe2 AO |
2695 | HOST_WIDE_INT sc = INTVAL (XEXP (y, 1)); |
2696 | unsigned HOST_WIDE_INT uc = sc; | |
146ec50f | 2697 | if (sc < 0 && pow2_or_zerop (-uc)) |
a9bf4fe2 | 2698 | { |
9f61be58 | 2699 | if (maybe_gt (ysize, 0)) |
5147bf6a | 2700 | ysize = -ysize; |
9f61be58 | 2701 | if (maybe_ne (ysize, 0)) |
3aa03517 | 2702 | ysize += sc + 1; |
fe8fb1c4 | 2703 | c += sc + 1; |
a9bf4fe2 AO |
2704 | return memrefs_conflict_p (xsize, x, |
2705 | ysize, canon_rtx (XEXP (y, 0)), c); | |
2706 | } | |
c02f035f | 2707 | } |
9ae8ffe7 JL |
2708 | |
2709 | if (CONSTANT_P (x)) | |
2710 | { | |
9f61be58 RS |
2711 | poly_int64 cx, cy; |
2712 | if (poly_int_rtx_p (x, &cx) && poly_int_rtx_p (y, &cy)) | |
9ae8ffe7 | 2713 | { |
9f61be58 | 2714 | c += cy - cx; |
3aa03517 | 2715 | return offset_overlap_p (c, xsize, ysize); |
9ae8ffe7 JL |
2716 | } |
2717 | ||
2718 | if (GET_CODE (x) == CONST) | |
2719 | { | |
2720 | if (GET_CODE (y) == CONST) | |
2721 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), | |
2722 | ysize, canon_rtx (XEXP (y, 0)), c); | |
2723 | else | |
2724 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), | |
2725 | ysize, y, c); | |
2726 | } | |
2727 | if (GET_CODE (y) == CONST) | |
2728 | return memrefs_conflict_p (xsize, x, ysize, | |
2729 | canon_rtx (XEXP (y, 0)), c); | |
2730 | ||
3aa03517 AO |
2731 | /* Assume a potential overlap for symbolic addresses that went |
2732 | through alignment adjustments (i.e., that have negative | |
2733 | sizes), because we can't know how far they are from each | |
2734 | other. */ | |
9ae8ffe7 | 2735 | if (CONSTANT_P (y)) |
9f61be58 RS |
2736 | return (maybe_lt (xsize, 0) |
2737 | || maybe_lt (ysize, 0) | |
2738 | || offset_overlap_p (c, xsize, ysize)); | |
9ae8ffe7 | 2739 | |
f47e08d9 | 2740 | return -1; |
9ae8ffe7 | 2741 | } |
f47e08d9 RG |
2742 | |
2743 | return -1; | |
9ae8ffe7 JL |
2744 | } |
2745 | ||
2746 | /* Functions to compute memory dependencies. | |
2747 | ||
2748 | Since we process the insns in execution order, we can build tables | |
2749 | to keep track of what registers are fixed (and not aliased), what registers | |
2750 | are varying in known ways, and what registers are varying in unknown | |
2751 | ways. | |
2752 | ||
2753 | If both memory references are volatile, then there must always be a | |
67914693 | 2754 | dependence between the two references, since their order cannot be |
9ae8ffe7 | 2755 | changed. A volatile and non-volatile reference can be interchanged |
ca7fd9cd | 2756 | though. |
9ae8ffe7 | 2757 | |
53d9622b RS |
2758 | We also must allow AND addresses, because they may generate accesses |
2759 | outside the object being referenced. This is used to generate aligned | |
2760 | addresses from unaligned addresses, for instance, the alpha | |
dc1618bc | 2761 | storeqi_unaligned pattern. */ |
9ae8ffe7 JL |
2762 | |
2763 | /* Read dependence: X is read after read in MEM takes place. There can | |
96672a3e RH |
2764 | only be a dependence here if both reads are volatile, or if either is |
2765 | an explicit barrier. */ | |
9ae8ffe7 JL |
2766 | |
2767 | int | |
4f588890 | 2768 | read_dependence (const_rtx mem, const_rtx x) |
9ae8ffe7 | 2769 | { |
96672a3e RH |
2770 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) |
2771 | return true; | |
2772 | if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER | |
2773 | || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER) | |
2774 | return true; | |
2775 | return false; | |
9ae8ffe7 JL |
2776 | } |
2777 | ||
998d7deb RH |
2778 | /* Look at the bottom of the COMPONENT_REF list for a DECL, and return it. */ |
2779 | ||
2780 | static tree | |
4682ae04 | 2781 | decl_for_component_ref (tree x) |
998d7deb RH |
2782 | { |
2783 | do | |
2784 | { | |
2785 | x = TREE_OPERAND (x, 0); | |
2786 | } | |
2787 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
2788 | ||
2789 | return x && DECL_P (x) ? x : NULL_TREE; | |
2790 | } | |
2791 | ||
527210c4 RS |
2792 | /* Walk up the COMPONENT_REF list in X and adjust *OFFSET to compensate |
2793 | for the offset of the field reference. *KNOWN_P says whether the | |
2794 | offset is known. */ | |
998d7deb | 2795 | |
527210c4 RS |
2796 | static void |
2797 | adjust_offset_for_component_ref (tree x, bool *known_p, | |
d05d7551 | 2798 | poly_int64 *offset) |
998d7deb | 2799 | { |
527210c4 RS |
2800 | if (!*known_p) |
2801 | return; | |
ca7fd9cd | 2802 | do |
998d7deb | 2803 | { |
527210c4 | 2804 | tree xoffset = component_ref_field_offset (x); |
998d7deb | 2805 | tree field = TREE_OPERAND (x, 1); |
6e246559 | 2806 | if (!poly_int_tree_p (xoffset)) |
807e902e KZ |
2807 | { |
2808 | *known_p = false; | |
2809 | return; | |
2810 | } | |
998d7deb | 2811 | |
6e246559 RS |
2812 | poly_offset_int woffset |
2813 | = (wi::to_poly_offset (xoffset) | |
8de73453 | 2814 | + (wi::to_offset (DECL_FIELD_BIT_OFFSET (field)) |
6e246559 RS |
2815 | >> LOG2_BITS_PER_UNIT) |
2816 | + *offset); | |
2817 | if (!woffset.to_shwi (offset)) | |
527210c4 RS |
2818 | { |
2819 | *known_p = false; | |
2820 | return; | |
2821 | } | |
998d7deb RH |
2822 | |
2823 | x = TREE_OPERAND (x, 0); | |
2824 | } | |
2825 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
998d7deb RH |
2826 | } |
2827 | ||
95bd1dd7 | 2828 | /* Return nonzero if we can determine the exprs corresponding to memrefs |
c6ea834c BM |
2829 | X and Y and they do not overlap. |
2830 | If LOOP_VARIANT is set, skip offset-based disambiguation */ | |
a4311dfe | 2831 | |
2e4e39f6 | 2832 | int |
c6ea834c | 2833 | nonoverlapping_memrefs_p (const_rtx x, const_rtx y, bool loop_invariant) |
a4311dfe | 2834 | { |
998d7deb | 2835 | tree exprx = MEM_EXPR (x), expry = MEM_EXPR (y); |
a4311dfe RK |
2836 | rtx rtlx, rtly; |
2837 | rtx basex, basey; | |
527210c4 | 2838 | bool moffsetx_known_p, moffsety_known_p; |
d05d7551 RS |
2839 | poly_int64 moffsetx = 0, moffsety = 0; |
2840 | poly_int64 offsetx = 0, offsety = 0, sizex, sizey; | |
a4311dfe | 2841 | |
998d7deb RH |
2842 | /* Unless both have exprs, we can't tell anything. */ |
2843 | if (exprx == 0 || expry == 0) | |
2844 | return 0; | |
2b22e382 RG |
2845 | |
2846 | /* For spill-slot accesses make sure we have valid offsets. */ | |
2847 | if ((exprx == get_spill_slot_decl (false) | |
527210c4 | 2848 | && ! MEM_OFFSET_KNOWN_P (x)) |
2b22e382 | 2849 | || (expry == get_spill_slot_decl (false) |
527210c4 | 2850 | && ! MEM_OFFSET_KNOWN_P (y))) |
2b22e382 | 2851 | return 0; |
c22cacf3 | 2852 | |
998d7deb | 2853 | /* If the field reference test failed, look at the DECLs involved. */ |
527210c4 RS |
2854 | moffsetx_known_p = MEM_OFFSET_KNOWN_P (x); |
2855 | if (moffsetx_known_p) | |
2856 | moffsetx = MEM_OFFSET (x); | |
998d7deb RH |
2857 | if (TREE_CODE (exprx) == COMPONENT_REF) |
2858 | { | |
2e0c984c RG |
2859 | tree t = decl_for_component_ref (exprx); |
2860 | if (! t) | |
2861 | return 0; | |
527210c4 | 2862 | adjust_offset_for_component_ref (exprx, &moffsetx_known_p, &moffsetx); |
2e0c984c | 2863 | exprx = t; |
998d7deb | 2864 | } |
c67a1cf6 | 2865 | |
527210c4 RS |
2866 | moffsety_known_p = MEM_OFFSET_KNOWN_P (y); |
2867 | if (moffsety_known_p) | |
2868 | moffsety = MEM_OFFSET (y); | |
998d7deb RH |
2869 | if (TREE_CODE (expry) == COMPONENT_REF) |
2870 | { | |
2e0c984c RG |
2871 | tree t = decl_for_component_ref (expry); |
2872 | if (! t) | |
2873 | return 0; | |
527210c4 | 2874 | adjust_offset_for_component_ref (expry, &moffsety_known_p, &moffsety); |
2e0c984c | 2875 | expry = t; |
998d7deb RH |
2876 | } |
2877 | ||
2878 | if (! DECL_P (exprx) || ! DECL_P (expry)) | |
a4311dfe RK |
2879 | return 0; |
2880 | ||
1f9ceff1 AO |
2881 | /* If we refer to different gimple registers, or one gimple register |
2882 | and one non-gimple-register, we know they can't overlap. First, | |
2883 | gimple registers don't have their addresses taken. Now, there | |
2884 | could be more than one stack slot for (different versions of) the | |
2885 | same gimple register, but we can presumably tell they don't | |
2886 | overlap based on offsets from stack base addresses elsewhere. | |
2887 | It's important that we don't proceed to DECL_RTL, because gimple | |
2888 | registers may not pass DECL_RTL_SET_P, and make_decl_rtl won't be | |
2889 | able to do anything about them since no SSA information will have | |
2890 | remained to guide it. */ | |
2891 | if (is_gimple_reg (exprx) || is_gimple_reg (expry)) | |
2d88904a AO |
2892 | return exprx != expry |
2893 | || (moffsetx_known_p && moffsety_known_p | |
2894 | && MEM_SIZE_KNOWN_P (x) && MEM_SIZE_KNOWN_P (y) | |
2895 | && !offset_overlap_p (moffsety - moffsetx, | |
2896 | MEM_SIZE (x), MEM_SIZE (y))); | |
1f9ceff1 | 2897 | |
1307c758 RG |
2898 | /* With invalid code we can end up storing into the constant pool. |
2899 | Bail out to avoid ICEing when creating RTL for this. | |
2900 | See gfortran.dg/lto/20091028-2_0.f90. */ | |
2901 | if (TREE_CODE (exprx) == CONST_DECL | |
2902 | || TREE_CODE (expry) == CONST_DECL) | |
2903 | return 1; | |
2904 | ||
dca16798 JJ |
2905 | /* If one decl is known to be a function or label in a function and |
2906 | the other is some kind of data, they can't overlap. */ | |
2907 | if ((TREE_CODE (exprx) == FUNCTION_DECL | |
2908 | || TREE_CODE (exprx) == LABEL_DECL) | |
2909 | != (TREE_CODE (expry) == FUNCTION_DECL | |
2910 | || TREE_CODE (expry) == LABEL_DECL)) | |
2911 | return 1; | |
2912 | ||
5f4cebba JJ |
2913 | /* If either of the decls doesn't have DECL_RTL set (e.g. marked as |
2914 | living in multiple places), we can't tell anything. Exception | |
2915 | are FUNCTION_DECLs for which we can create DECL_RTL on demand. */ | |
2916 | if ((!DECL_RTL_SET_P (exprx) && TREE_CODE (exprx) != FUNCTION_DECL) | |
2917 | || (!DECL_RTL_SET_P (expry) && TREE_CODE (expry) != FUNCTION_DECL)) | |
2918 | return 0; | |
2919 | ||
998d7deb RH |
2920 | rtlx = DECL_RTL (exprx); |
2921 | rtly = DECL_RTL (expry); | |
a4311dfe | 2922 | |
1edcd60b RK |
2923 | /* If either RTL is not a MEM, it must be a REG or CONCAT, meaning they |
2924 | can't overlap unless they are the same because we never reuse that part | |
2925 | of the stack frame used for locals for spilled pseudos. */ | |
3c0cb5de | 2926 | if ((!MEM_P (rtlx) || !MEM_P (rtly)) |
1edcd60b | 2927 | && ! rtx_equal_p (rtlx, rtly)) |
a4311dfe RK |
2928 | return 1; |
2929 | ||
5932a4d4 | 2930 | /* If we have MEMs referring to different address spaces (which can |
09e881c9 BE |
2931 | potentially overlap), we cannot easily tell from the addresses |
2932 | whether the references overlap. */ | |
2933 | if (MEM_P (rtlx) && MEM_P (rtly) | |
2934 | && MEM_ADDR_SPACE (rtlx) != MEM_ADDR_SPACE (rtly)) | |
2935 | return 0; | |
2936 | ||
a4311dfe RK |
2937 | /* Get the base and offsets of both decls. If either is a register, we |
2938 | know both are and are the same, so use that as the base. The only | |
2939 | we can avoid overlap is if we can deduce that they are nonoverlapping | |
2940 | pieces of that decl, which is very rare. */ | |
3c0cb5de | 2941 | basex = MEM_P (rtlx) ? XEXP (rtlx, 0) : rtlx; |
d05d7551 | 2942 | basex = strip_offset_and_add (basex, &offsetx); |
a4311dfe | 2943 | |
3c0cb5de | 2944 | basey = MEM_P (rtly) ? XEXP (rtly, 0) : rtly; |
d05d7551 | 2945 | basey = strip_offset_and_add (basey, &offsety); |
a4311dfe | 2946 | |
d746694a | 2947 | /* If the bases are different, we know they do not overlap if both |
ca7fd9cd | 2948 | are constants or if one is a constant and the other a pointer into the |
d746694a RK |
2949 | stack frame. Otherwise a different base means we can't tell if they |
2950 | overlap or not. */ | |
54363f8a | 2951 | if (compare_base_decls (exprx, expry) == 0) |
ca7fd9cd KH |
2952 | return ((CONSTANT_P (basex) && CONSTANT_P (basey)) |
2953 | || (CONSTANT_P (basex) && REG_P (basey) | |
2954 | && REGNO_PTR_FRAME_P (REGNO (basey))) | |
2955 | || (CONSTANT_P (basey) && REG_P (basex) | |
2956 | && REGNO_PTR_FRAME_P (REGNO (basex)))); | |
a4311dfe | 2957 | |
c6ea834c BM |
2958 | /* Offset based disambiguation not appropriate for loop invariant */ |
2959 | if (loop_invariant) | |
dca16798 | 2960 | return 0; |
c6ea834c | 2961 | |
54363f8a JH |
2962 | /* Offset based disambiguation is OK even if we do not know that the |
2963 | declarations are necessarily different | |
2964 | (i.e. compare_base_decls (exprx, expry) == -1) */ | |
2965 | ||
d05d7551 | 2966 | sizex = (!MEM_P (rtlx) ? poly_int64 (GET_MODE_SIZE (GET_MODE (rtlx))) |
f5541398 | 2967 | : MEM_SIZE_KNOWN_P (rtlx) ? MEM_SIZE (rtlx) |
a4311dfe | 2968 | : -1); |
d05d7551 | 2969 | sizey = (!MEM_P (rtly) ? poly_int64 (GET_MODE_SIZE (GET_MODE (rtly))) |
f5541398 RS |
2970 | : MEM_SIZE_KNOWN_P (rtly) ? MEM_SIZE (rtly) |
2971 | : -1); | |
a4311dfe | 2972 | |
0af5bc3e RK |
2973 | /* If we have an offset for either memref, it can update the values computed |
2974 | above. */ | |
527210c4 RS |
2975 | if (moffsetx_known_p) |
2976 | offsetx += moffsetx, sizex -= moffsetx; | |
2977 | if (moffsety_known_p) | |
2978 | offsety += moffsety, sizey -= moffsety; | |
a4311dfe | 2979 | |
0af5bc3e | 2980 | /* If a memref has both a size and an offset, we can use the smaller size. |
efc981bb | 2981 | We can't do this if the offset isn't known because we must view this |
0af5bc3e | 2982 | memref as being anywhere inside the DECL's MEM. */ |
527210c4 | 2983 | if (MEM_SIZE_KNOWN_P (x) && moffsetx_known_p) |
f5541398 | 2984 | sizex = MEM_SIZE (x); |
527210c4 | 2985 | if (MEM_SIZE_KNOWN_P (y) && moffsety_known_p) |
f5541398 | 2986 | sizey = MEM_SIZE (y); |
a4311dfe | 2987 | |
d05d7551 | 2988 | return !ranges_maybe_overlap_p (offsetx, sizex, offsety, sizey); |
a4311dfe RK |
2989 | } |
2990 | ||
9362286d SB |
2991 | /* Helper for true_dependence and canon_true_dependence. |
2992 | Checks for true dependence: X is read after store in MEM takes place. | |
9ae8ffe7 | 2993 | |
9362286d SB |
2994 | If MEM_CANONICALIZED is FALSE, then X_ADDR and MEM_ADDR should be |
2995 | NULL_RTX, and the canonical addresses of MEM and X are both computed | |
2996 | here. If MEM_CANONICALIZED, then MEM must be already canonicalized. | |
2997 | ||
2998 | If X_ADDR is non-NULL, it is used in preference of XEXP (x, 0). | |
2999 | ||
3000 | Returns 1 if there is a true dependence, 0 otherwise. */ | |
3001 | ||
3002 | static int | |
ef4bddc2 | 3003 | true_dependence_1 (const_rtx mem, machine_mode mem_mode, rtx mem_addr, |
53d9622b | 3004 | const_rtx x, rtx x_addr, bool mem_canonicalized) |
9ae8ffe7 | 3005 | { |
0777fc02 | 3006 | rtx true_mem_addr; |
49982682 | 3007 | rtx base; |
f47e08d9 | 3008 | int ret; |
9ae8ffe7 | 3009 | |
9362286d SB |
3010 | gcc_checking_assert (mem_canonicalized ? (mem_addr != NULL_RTX) |
3011 | : (mem_addr == NULL_RTX && x_addr == NULL_RTX)); | |
3012 | ||
9ae8ffe7 JL |
3013 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) |
3014 | return 1; | |
3015 | ||
c4484b8f | 3016 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
ac3768f6 | 3017 | This is used in epilogue deallocation functions, and in cselib. */ |
c4484b8f RH |
3018 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) |
3019 | return 1; | |
3020 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
3021 | return 1; | |
9cd9e512 RH |
3022 | if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER |
3023 | || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER) | |
3024 | return 1; | |
c4484b8f | 3025 | |
0777fc02 UB |
3026 | if (! x_addr) |
3027 | x_addr = XEXP (x, 0); | |
3028 | x_addr = get_addr (x_addr); | |
3029 | ||
9362286d SB |
3030 | if (! mem_addr) |
3031 | { | |
3032 | mem_addr = XEXP (mem, 0); | |
3033 | if (mem_mode == VOIDmode) | |
3034 | mem_mode = GET_MODE (mem); | |
3035 | } | |
0777fc02 | 3036 | true_mem_addr = get_addr (mem_addr); |
eab5c70a | 3037 | |
878f5596 UB |
3038 | /* Read-only memory is by definition never modified, and therefore can't |
3039 | conflict with anything. However, don't assume anything when AND | |
3040 | addresses are involved and leave to the code below to determine | |
3041 | dependence. We don't expect to find read-only set on MEM, but | |
3042 | stupid user tricks can produce them, so don't die. */ | |
3043 | if (MEM_READONLY_P (x) | |
3044 | && GET_CODE (x_addr) != AND | |
0777fc02 | 3045 | && GET_CODE (true_mem_addr) != AND) |
878f5596 UB |
3046 | return 0; |
3047 | ||
3048 | /* If we have MEMs referring to different address spaces (which can | |
3049 | potentially overlap), we cannot easily tell from the addresses | |
3050 | whether the references overlap. */ | |
3051 | if (MEM_ADDR_SPACE (mem) != MEM_ADDR_SPACE (x)) | |
3052 | return 1; | |
3053 | ||
55efb413 JW |
3054 | base = find_base_term (x_addr); |
3055 | if (base && (GET_CODE (base) == LABEL_REF | |
3056 | || (GET_CODE (base) == SYMBOL_REF | |
3057 | && CONSTANT_POOL_ADDRESS_P (base)))) | |
3058 | return 0; | |
3059 | ||
0777fc02 UB |
3060 | rtx mem_base = find_base_term (true_mem_addr); |
3061 | if (! base_alias_check (x_addr, base, true_mem_addr, mem_base, | |
31b0a960 | 3062 | GET_MODE (x), mem_mode)) |
1c72c7f6 JC |
3063 | return 0; |
3064 | ||
eab5c70a | 3065 | x_addr = canon_rtx (x_addr); |
9362286d | 3066 | if (!mem_canonicalized) |
0777fc02 | 3067 | mem_addr = canon_rtx (true_mem_addr); |
6e73e666 | 3068 | |
f47e08d9 RG |
3069 | if ((ret = memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr, |
3070 | SIZE_FOR_MODE (x), x_addr, 0)) != -1) | |
3071 | return ret; | |
3072 | ||
a95b3cc7 | 3073 | if (mems_in_disjoint_alias_sets_p (x, mem)) |
f47e08d9 RG |
3074 | return 0; |
3075 | ||
c6ea834c | 3076 | if (nonoverlapping_memrefs_p (mem, x, false)) |
0211b6ab | 3077 | return 0; |
175a7536 | 3078 | |
55b34b5f | 3079 | return rtx_refs_may_alias_p (x, mem, true); |
a13d4ebf AM |
3080 | } |
3081 | ||
9362286d SB |
3082 | /* True dependence: X is read after store in MEM takes place. */ |
3083 | ||
3084 | int | |
ef4bddc2 | 3085 | true_dependence (const_rtx mem, machine_mode mem_mode, const_rtx x) |
9362286d SB |
3086 | { |
3087 | return true_dependence_1 (mem, mem_mode, NULL_RTX, | |
53d9622b | 3088 | x, NULL_RTX, /*mem_canonicalized=*/false); |
9362286d SB |
3089 | } |
3090 | ||
a13d4ebf | 3091 | /* Canonical true dependence: X is read after store in MEM takes place. |
ca7fd9cd KH |
3092 | Variant of true_dependence which assumes MEM has already been |
3093 | canonicalized (hence we no longer do that here). | |
9362286d SB |
3094 | The mem_addr argument has been added, since true_dependence_1 computed |
3095 | this value prior to canonicalizing. */ | |
a13d4ebf AM |
3096 | |
3097 | int | |
ef4bddc2 | 3098 | canon_true_dependence (const_rtx mem, machine_mode mem_mode, rtx mem_addr, |
53d9622b | 3099 | const_rtx x, rtx x_addr) |
a13d4ebf | 3100 | { |
9362286d | 3101 | return true_dependence_1 (mem, mem_mode, mem_addr, |
53d9622b | 3102 | x, x_addr, /*mem_canonicalized=*/true); |
9ae8ffe7 JL |
3103 | } |
3104 | ||
da7d8304 | 3105 | /* Returns nonzero if a write to X might alias a previous read from |
393f9fed | 3106 | (or, if WRITEP is true, a write to) MEM. |
bd280792 JR |
3107 | If X_CANONCALIZED is true, then X_ADDR is the canonicalized address of X, |
3108 | and X_MODE the mode for that access. | |
3109 | If MEM_CANONICALIZED is true, MEM is canonicalized. */ | |
9ae8ffe7 | 3110 | |
2c72b78f | 3111 | static int |
bd280792 | 3112 | write_dependence_p (const_rtx mem, |
ef4bddc2 | 3113 | const_rtx x, machine_mode x_mode, rtx x_addr, |
bd280792 | 3114 | bool mem_canonicalized, bool x_canonicalized, bool writep) |
9ae8ffe7 | 3115 | { |
bd280792 | 3116 | rtx mem_addr; |
0777fc02 | 3117 | rtx true_mem_addr, true_x_addr; |
49982682 | 3118 | rtx base; |
f47e08d9 | 3119 | int ret; |
6e73e666 | 3120 | |
bd280792 | 3121 | gcc_checking_assert (x_canonicalized |
6f5799be JJ |
3122 | ? (x_addr != NULL_RTX |
3123 | && (x_mode != VOIDmode || GET_MODE (x) == VOIDmode)) | |
bd280792 | 3124 | : (x_addr == NULL_RTX && x_mode == VOIDmode)); |
393f9fed | 3125 | |
9ae8ffe7 JL |
3126 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) |
3127 | return 1; | |
3128 | ||
c4484b8f RH |
3129 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
3130 | This is used in epilogue deallocation functions. */ | |
3131 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) | |
3132 | return 1; | |
3133 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
3134 | return 1; | |
9cd9e512 RH |
3135 | if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER |
3136 | || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER) | |
3137 | return 1; | |
c4484b8f | 3138 | |
bd280792 | 3139 | if (!x_addr) |
0777fc02 UB |
3140 | x_addr = XEXP (x, 0); |
3141 | true_x_addr = get_addr (x_addr); | |
3142 | ||
3143 | mem_addr = XEXP (mem, 0); | |
3144 | true_mem_addr = get_addr (mem_addr); | |
55efb413 | 3145 | |
878f5596 UB |
3146 | /* A read from read-only memory can't conflict with read-write memory. |
3147 | Don't assume anything when AND addresses are involved and leave to | |
3148 | the code below to determine dependence. */ | |
3149 | if (!writep | |
3150 | && MEM_READONLY_P (mem) | |
0777fc02 UB |
3151 | && GET_CODE (true_x_addr) != AND |
3152 | && GET_CODE (true_mem_addr) != AND) | |
878f5596 UB |
3153 | return 0; |
3154 | ||
3155 | /* If we have MEMs referring to different address spaces (which can | |
3156 | potentially overlap), we cannot easily tell from the addresses | |
3157 | whether the references overlap. */ | |
3158 | if (MEM_ADDR_SPACE (mem) != MEM_ADDR_SPACE (x)) | |
3159 | return 1; | |
3160 | ||
0777fc02 | 3161 | base = find_base_term (true_mem_addr); |
31b0a960 RB |
3162 | if (! writep |
3163 | && base | |
3164 | && (GET_CODE (base) == LABEL_REF | |
3165 | || (GET_CODE (base) == SYMBOL_REF | |
3166 | && CONSTANT_POOL_ADDRESS_P (base)))) | |
3167 | return 0; | |
49982682 | 3168 | |
0777fc02 UB |
3169 | rtx x_base = find_base_term (true_x_addr); |
3170 | if (! base_alias_check (true_x_addr, x_base, true_mem_addr, base, | |
3171 | GET_MODE (x), GET_MODE (mem))) | |
41472af8 MM |
3172 | return 0; |
3173 | ||
bd280792 | 3174 | if (!x_canonicalized) |
393f9fed | 3175 | { |
0777fc02 | 3176 | x_addr = canon_rtx (true_x_addr); |
bd280792 | 3177 | x_mode = GET_MODE (x); |
393f9fed | 3178 | } |
bd280792 | 3179 | if (!mem_canonicalized) |
0777fc02 | 3180 | mem_addr = canon_rtx (true_mem_addr); |
6e73e666 | 3181 | |
bd280792 JR |
3182 | if ((ret = memrefs_conflict_p (SIZE_FOR_MODE (mem), mem_addr, |
3183 | GET_MODE_SIZE (x_mode), x_addr, 0)) != -1) | |
f47e08d9 RG |
3184 | return ret; |
3185 | ||
c6ea834c | 3186 | if (nonoverlapping_memrefs_p (x, mem, false)) |
c6df88cb MM |
3187 | return 0; |
3188 | ||
55b34b5f | 3189 | return rtx_refs_may_alias_p (x, mem, false); |
c6df88cb MM |
3190 | } |
3191 | ||
3192 | /* Anti dependence: X is written after read in MEM takes place. */ | |
3193 | ||
3194 | int | |
4f588890 | 3195 | anti_dependence (const_rtx mem, const_rtx x) |
c6df88cb | 3196 | { |
bd280792 JR |
3197 | return write_dependence_p (mem, x, VOIDmode, NULL_RTX, |
3198 | /*mem_canonicalized=*/false, | |
3199 | /*x_canonicalized*/false, /*writep=*/false); | |
393f9fed JR |
3200 | } |
3201 | ||
bd280792 JR |
3202 | /* Likewise, but we already have a canonicalized MEM, and X_ADDR for X. |
3203 | Also, consider X in X_MODE (which might be from an enclosing | |
3204 | STRICT_LOW_PART / ZERO_EXTRACT). | |
3205 | If MEM_CANONICALIZED is true, MEM is canonicalized. */ | |
393f9fed JR |
3206 | |
3207 | int | |
bd280792 | 3208 | canon_anti_dependence (const_rtx mem, bool mem_canonicalized, |
ef4bddc2 | 3209 | const_rtx x, machine_mode x_mode, rtx x_addr) |
393f9fed | 3210 | { |
bd280792 JR |
3211 | return write_dependence_p (mem, x, x_mode, x_addr, |
3212 | mem_canonicalized, /*x_canonicalized=*/true, | |
3213 | /*writep=*/false); | |
9ae8ffe7 JL |
3214 | } |
3215 | ||
3216 | /* Output dependence: X is written after store in MEM takes place. */ | |
3217 | ||
3218 | int | |
4f588890 | 3219 | output_dependence (const_rtx mem, const_rtx x) |
9ae8ffe7 | 3220 | { |
bd280792 JR |
3221 | return write_dependence_p (mem, x, VOIDmode, NULL_RTX, |
3222 | /*mem_canonicalized=*/false, | |
3223 | /*x_canonicalized*/false, /*writep=*/true); | |
9ae8ffe7 | 3224 | } |
43b9f499 RB |
3225 | |
3226 | /* Likewise, but we already have a canonicalized MEM, and X_ADDR for X. | |
3227 | Also, consider X in X_MODE (which might be from an enclosing | |
3228 | STRICT_LOW_PART / ZERO_EXTRACT). | |
3229 | If MEM_CANONICALIZED is true, MEM is canonicalized. */ | |
3230 | ||
3231 | int | |
3232 | canon_output_dependence (const_rtx mem, bool mem_canonicalized, | |
3233 | const_rtx x, machine_mode x_mode, rtx x_addr) | |
3234 | { | |
3235 | return write_dependence_p (mem, x, x_mode, x_addr, | |
3236 | mem_canonicalized, /*x_canonicalized=*/true, | |
3237 | /*writep=*/true); | |
3238 | } | |
c14b9960 | 3239 | \f |
6e73e666 | 3240 | |
c6ea834c BM |
3241 | |
3242 | /* Check whether X may be aliased with MEM. Don't do offset-based | |
3243 | memory disambiguation & TBAA. */ | |
3244 | int | |
3245 | may_alias_p (const_rtx mem, const_rtx x) | |
3246 | { | |
3247 | rtx x_addr, mem_addr; | |
c6ea834c BM |
3248 | |
3249 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) | |
3250 | return 1; | |
3251 | ||
a95b3cc7 RG |
3252 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
3253 | This is used in epilogue deallocation functions. */ | |
3254 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) | |
3255 | return 1; | |
3256 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
c6ea834c | 3257 | return 1; |
c6ea834c BM |
3258 | if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER |
3259 | || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER) | |
3260 | return 1; | |
3261 | ||
c6ea834c | 3262 | x_addr = XEXP (x, 0); |
0777fc02 UB |
3263 | x_addr = get_addr (x_addr); |
3264 | ||
c6ea834c | 3265 | mem_addr = XEXP (mem, 0); |
0777fc02 | 3266 | mem_addr = get_addr (mem_addr); |
c6ea834c | 3267 | |
878f5596 UB |
3268 | /* Read-only memory is by definition never modified, and therefore can't |
3269 | conflict with anything. However, don't assume anything when AND | |
3270 | addresses are involved and leave to the code below to determine | |
3271 | dependence. We don't expect to find read-only set on MEM, but | |
3272 | stupid user tricks can produce them, so don't die. */ | |
3273 | if (MEM_READONLY_P (x) | |
3274 | && GET_CODE (x_addr) != AND | |
3275 | && GET_CODE (mem_addr) != AND) | |
3276 | return 0; | |
3277 | ||
3278 | /* If we have MEMs referring to different address spaces (which can | |
3279 | potentially overlap), we cannot easily tell from the addresses | |
3280 | whether the references overlap. */ | |
3281 | if (MEM_ADDR_SPACE (mem) != MEM_ADDR_SPACE (x)) | |
3282 | return 1; | |
3283 | ||
31b0a960 RB |
3284 | rtx x_base = find_base_term (x_addr); |
3285 | rtx mem_base = find_base_term (mem_addr); | |
3286 | if (! base_alias_check (x_addr, x_base, mem_addr, mem_base, | |
3287 | GET_MODE (x), GET_MODE (mem_addr))) | |
c6ea834c BM |
3288 | return 0; |
3289 | ||
c6ea834c BM |
3290 | if (nonoverlapping_memrefs_p (mem, x, true)) |
3291 | return 0; | |
3292 | ||
c6ea834c BM |
3293 | /* TBAA not valid for loop_invarint */ |
3294 | return rtx_refs_may_alias_p (x, mem, false); | |
3295 | } | |
3296 | ||
6e73e666 | 3297 | void |
b5deb7b6 | 3298 | init_alias_target (void) |
6e73e666 | 3299 | { |
b3694847 | 3300 | int i; |
6e73e666 | 3301 | |
9fc37b2b RS |
3302 | if (!arg_base_value) |
3303 | arg_base_value = gen_rtx_ADDRESS (VOIDmode, 0); | |
3304 | ||
b5deb7b6 SL |
3305 | memset (static_reg_base_value, 0, sizeof static_reg_base_value); |
3306 | ||
6e73e666 JC |
3307 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) |
3308 | /* Check whether this register can hold an incoming pointer | |
3309 | argument. FUNCTION_ARG_REGNO_P tests outgoing register | |
ec5c56db | 3310 | numbers, so translate if necessary due to register windows. */ |
6e73e666 | 3311 | if (FUNCTION_ARG_REGNO_P (OUTGOING_REGNO (i)) |
f939c3e6 | 3312 | && targetm.hard_regno_mode_ok (i, Pmode)) |
9fc37b2b RS |
3313 | static_reg_base_value[i] = arg_base_value; |
3314 | ||
e6eacdc9 RS |
3315 | /* RTL code is required to be consistent about whether it uses the |
3316 | stack pointer, the frame pointer or the argument pointer to | |
3317 | access a given area of the frame. We can therefore use the | |
3318 | base address to distinguish between the different areas. */ | |
757e8ba2 JJ |
3319 | static_reg_base_value[STACK_POINTER_REGNUM] |
3320 | = unique_base_value (UNIQUE_BASE_VALUE_SP); | |
3321 | static_reg_base_value[ARG_POINTER_REGNUM] | |
3322 | = unique_base_value (UNIQUE_BASE_VALUE_ARGP); | |
3323 | static_reg_base_value[FRAME_POINTER_REGNUM] | |
3324 | = unique_base_value (UNIQUE_BASE_VALUE_FP); | |
e6eacdc9 RS |
3325 | |
3326 | /* The above rules extend post-reload, with eliminations applying | |
3327 | consistently to each of the three pointers. Cope with cases in | |
3328 | which the frame pointer is eliminated to the hard frame pointer | |
3329 | rather than the stack pointer. */ | |
c3e08036 TS |
3330 | if (!HARD_FRAME_POINTER_IS_FRAME_POINTER) |
3331 | static_reg_base_value[HARD_FRAME_POINTER_REGNUM] | |
3332 | = unique_base_value (UNIQUE_BASE_VALUE_HFP); | |
bf1660a6 JL |
3333 | } |
3334 | ||
7b52eede JH |
3335 | /* Set MEMORY_MODIFIED when X modifies DATA (that is assumed |
3336 | to be memory reference. */ | |
3337 | static bool memory_modified; | |
3338 | static void | |
aa317c97 | 3339 | memory_modified_1 (rtx x, const_rtx pat ATTRIBUTE_UNUSED, void *data) |
7b52eede | 3340 | { |
3c0cb5de | 3341 | if (MEM_P (x)) |
7b52eede | 3342 | { |
9678086d | 3343 | if (anti_dependence (x, (const_rtx)data) || output_dependence (x, (const_rtx)data)) |
7b52eede JH |
3344 | memory_modified = true; |
3345 | } | |
3346 | } | |
3347 | ||
3348 | ||
3349 | /* Return true when INSN possibly modify memory contents of MEM | |
454ff5cb | 3350 | (i.e. address can be modified). */ |
7b52eede | 3351 | bool |
9678086d | 3352 | memory_modified_in_insn_p (const_rtx mem, const_rtx insn) |
7b52eede JH |
3353 | { |
3354 | if (!INSN_P (insn)) | |
3355 | return false; | |
bc36c711 JJ |
3356 | /* Conservatively assume all non-readonly MEMs might be modified in |
3357 | calls. */ | |
3358 | if (CALL_P (insn)) | |
3359 | return true; | |
7b52eede | 3360 | memory_modified = false; |
e8448ba5 RS |
3361 | note_stores (as_a<const rtx_insn *> (insn), memory_modified_1, |
3362 | CONST_CAST_RTX(mem)); | |
7b52eede JH |
3363 | return memory_modified; |
3364 | } | |
3365 | ||
c13e8210 MM |
3366 | /* Initialize the aliasing machinery. Initialize the REG_KNOWN_VALUE |
3367 | array. */ | |
3368 | ||
9ae8ffe7 | 3369 | void |
4682ae04 | 3370 | init_alias_analysis (void) |
9ae8ffe7 | 3371 | { |
c582d54a | 3372 | unsigned int maxreg = max_reg_num (); |
ea64ef27 | 3373 | int changed, pass; |
b3694847 SS |
3374 | int i; |
3375 | unsigned int ui; | |
d36a28b8 DM |
3376 | rtx_insn *insn; |
3377 | rtx val; | |
131db6b8 SB |
3378 | int rpo_cnt; |
3379 | int *rpo; | |
9ae8ffe7 | 3380 | |
0d446150 JH |
3381 | timevar_push (TV_ALIAS_ANALYSIS); |
3382 | ||
cb3874dc ML |
3383 | vec_safe_grow_cleared (reg_known_value, maxreg - FIRST_PSEUDO_REGISTER, |
3384 | true); | |
9ff3c7ca | 3385 | reg_known_equiv_p = sbitmap_alloc (maxreg - FIRST_PSEUDO_REGISTER); |
dd3d1ec0 | 3386 | bitmap_clear (reg_known_equiv_p); |
9ae8ffe7 | 3387 | |
08c79682 | 3388 | /* If we have memory allocated from the previous run, use it. */ |
c582d54a | 3389 | if (old_reg_base_value) |
08c79682 KH |
3390 | reg_base_value = old_reg_base_value; |
3391 | ||
3392 | if (reg_base_value) | |
9771b263 | 3393 | reg_base_value->truncate (0); |
08c79682 | 3394 | |
cb3874dc | 3395 | vec_safe_grow_cleared (reg_base_value, maxreg, true); |
ac606739 | 3396 | |
5ed6ace5 | 3397 | new_reg_base_value = XNEWVEC (rtx, maxreg); |
d630245f | 3398 | reg_seen = sbitmap_alloc (maxreg); |
ec907dd8 JL |
3399 | |
3400 | /* The basic idea is that each pass through this loop will use the | |
3401 | "constant" information from the previous pass to propagate alias | |
3402 | information through another level of assignments. | |
3403 | ||
131db6b8 SB |
3404 | The propagation is done on the CFG in reverse post-order, to propagate |
3405 | things forward as far as possible in each iteration. | |
3406 | ||
ec907dd8 JL |
3407 | This could get expensive if the assignment chains are long. Maybe |
3408 | we should throttle the number of iterations, possibly based on | |
6e73e666 | 3409 | the optimization level or flag_expensive_optimizations. |
ec907dd8 JL |
3410 | |
3411 | We could propagate more information in the first pass by making use | |
6fb5fa3c | 3412 | of DF_REG_DEF_COUNT to determine immediately that the alias information |
ea64ef27 JL |
3413 | for a pseudo is "constant". |
3414 | ||
3415 | A program with an uninitialized variable can cause an infinite loop | |
3416 | here. Instead of doing a full dataflow analysis to detect such problems | |
3417 | we just cap the number of iterations for the loop. | |
3418 | ||
3419 | The state of the arrays for the set chain in question does not matter | |
3420 | since the program has undefined behavior. */ | |
6e73e666 | 3421 | |
0cae8d31 | 3422 | rpo = XNEWVEC (int, n_basic_blocks_for_fn (cfun)); |
131db6b8 SB |
3423 | rpo_cnt = pre_and_rev_post_order_compute (NULL, rpo, false); |
3424 | ||
ea64ef27 | 3425 | pass = 0; |
6e73e666 | 3426 | do |
ec907dd8 JL |
3427 | { |
3428 | /* Assume nothing will change this iteration of the loop. */ | |
3429 | changed = 0; | |
3430 | ||
ec907dd8 | 3431 | /* We want to assign the same IDs each iteration of this loop, so |
9fc37b2b RS |
3432 | start counting from one each iteration of the loop. */ |
3433 | unique_id = 1; | |
ec907dd8 | 3434 | |
f5143c46 | 3435 | /* We're at the start of the function each iteration through the |
ec907dd8 | 3436 | loop, so we're copying arguments. */ |
83bbd9b6 | 3437 | copying_arguments = true; |
9ae8ffe7 | 3438 | |
6e73e666 | 3439 | /* Wipe the potential alias information clean for this pass. */ |
c582d54a | 3440 | memset (new_reg_base_value, 0, maxreg * sizeof (rtx)); |
8072f69c | 3441 | |
6e73e666 | 3442 | /* Wipe the reg_seen array clean. */ |
f61e445a | 3443 | bitmap_clear (reg_seen); |
9ae8ffe7 | 3444 | |
356610cb EB |
3445 | /* Initialize the alias information for this pass. */ |
3446 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) | |
e6eacdc9 RS |
3447 | if (static_reg_base_value[i] |
3448 | /* Don't treat the hard frame pointer as special if we | |
3449 | eliminated the frame pointer to the stack pointer instead. */ | |
3450 | && !(i == HARD_FRAME_POINTER_REGNUM | |
3451 | && reload_completed | |
3452 | && !frame_pointer_needed | |
3453 | && targetm.can_eliminate (FRAME_POINTER_REGNUM, | |
3454 | STACK_POINTER_REGNUM))) | |
356610cb EB |
3455 | { |
3456 | new_reg_base_value[i] = static_reg_base_value[i]; | |
3457 | bitmap_set_bit (reg_seen, i); | |
3458 | } | |
6e73e666 | 3459 | |
ec907dd8 | 3460 | /* Walk the insns adding values to the new_reg_base_value array. */ |
131db6b8 | 3461 | for (i = 0; i < rpo_cnt; i++) |
9ae8ffe7 | 3462 | { |
06e28de2 | 3463 | basic_block bb = BASIC_BLOCK_FOR_FN (cfun, rpo[i]); |
131db6b8 | 3464 | FOR_BB_INSNS (bb, insn) |
ec907dd8 | 3465 | { |
131db6b8 SB |
3466 | if (NONDEBUG_INSN_P (insn)) |
3467 | { | |
3468 | rtx note, set; | |
efc9bd41 | 3469 | |
131db6b8 SB |
3470 | /* If this insn has a noalias note, process it, Otherwise, |
3471 | scan for sets. A simple set will have no side effects | |
3472 | which could change the base value of any other register. */ | |
6e73e666 | 3473 | |
131db6b8 SB |
3474 | if (GET_CODE (PATTERN (insn)) == SET |
3475 | && REG_NOTES (insn) != 0 | |
3476 | && find_reg_note (insn, REG_NOALIAS, NULL_RTX)) | |
3477 | record_set (SET_DEST (PATTERN (insn)), NULL_RTX, NULL); | |
3478 | else | |
e8448ba5 | 3479 | note_stores (insn, record_set, NULL); |
6e73e666 | 3480 | |
131db6b8 | 3481 | set = single_set (insn); |
6e73e666 | 3482 | |
131db6b8 SB |
3483 | if (set != 0 |
3484 | && REG_P (SET_DEST (set)) | |
3485 | && REGNO (SET_DEST (set)) >= FIRST_PSEUDO_REGISTER) | |
713f41f9 | 3486 | { |
131db6b8 SB |
3487 | unsigned int regno = REGNO (SET_DEST (set)); |
3488 | rtx src = SET_SRC (set); | |
3489 | rtx t; | |
3490 | ||
3491 | note = find_reg_equal_equiv_note (insn); | |
3492 | if (note && REG_NOTE_KIND (note) == REG_EQUAL | |
3493 | && DF_REG_DEF_COUNT (regno) != 1) | |
3494 | note = NULL_RTX; | |
3495 | ||
5284e559 | 3496 | poly_int64 offset; |
131db6b8 SB |
3497 | if (note != NULL_RTX |
3498 | && GET_CODE (XEXP (note, 0)) != EXPR_LIST | |
3499 | && ! rtx_varies_p (XEXP (note, 0), 1) | |
3500 | && ! reg_overlap_mentioned_p (SET_DEST (set), | |
3501 | XEXP (note, 0))) | |
3502 | { | |
3503 | set_reg_known_value (regno, XEXP (note, 0)); | |
3504 | set_reg_known_equiv_p (regno, | |
3505 | REG_NOTE_KIND (note) == REG_EQUIV); | |
3506 | } | |
3507 | else if (DF_REG_DEF_COUNT (regno) == 1 | |
3508 | && GET_CODE (src) == PLUS | |
3509 | && REG_P (XEXP (src, 0)) | |
3510 | && (t = get_reg_known_value (REGNO (XEXP (src, 0)))) | |
5284e559 | 3511 | && poly_int_rtx_p (XEXP (src, 1), &offset)) |
131db6b8 | 3512 | { |
5284e559 | 3513 | t = plus_constant (GET_MODE (src), t, offset); |
131db6b8 SB |
3514 | set_reg_known_value (regno, t); |
3515 | set_reg_known_equiv_p (regno, false); | |
3516 | } | |
3517 | else if (DF_REG_DEF_COUNT (regno) == 1 | |
3518 | && ! rtx_varies_p (src, 1)) | |
3519 | { | |
3520 | set_reg_known_value (regno, src); | |
3521 | set_reg_known_equiv_p (regno, false); | |
3522 | } | |
713f41f9 | 3523 | } |
6e73e666 | 3524 | } |
131db6b8 SB |
3525 | else if (NOTE_P (insn) |
3526 | && NOTE_KIND (insn) == NOTE_INSN_FUNCTION_BEG) | |
3527 | copying_arguments = false; | |
ec907dd8 | 3528 | } |
6e73e666 | 3529 | } |
ec907dd8 | 3530 | |
6e73e666 | 3531 | /* Now propagate values from new_reg_base_value to reg_base_value. */ |
62e5bf5d | 3532 | gcc_assert (maxreg == (unsigned int) max_reg_num ()); |
c22cacf3 | 3533 | |
c582d54a | 3534 | for (ui = 0; ui < maxreg; ui++) |
6e73e666 | 3535 | { |
e51712db | 3536 | if (new_reg_base_value[ui] |
9771b263 DN |
3537 | && new_reg_base_value[ui] != (*reg_base_value)[ui] |
3538 | && ! rtx_equal_p (new_reg_base_value[ui], (*reg_base_value)[ui])) | |
ec907dd8 | 3539 | { |
9771b263 | 3540 | (*reg_base_value)[ui] = new_reg_base_value[ui]; |
6e73e666 | 3541 | changed = 1; |
ec907dd8 | 3542 | } |
9ae8ffe7 | 3543 | } |
9ae8ffe7 | 3544 | } |
6e73e666 | 3545 | while (changed && ++pass < MAX_ALIAS_LOOP_PASSES); |
131db6b8 | 3546 | XDELETEVEC (rpo); |
9ae8ffe7 JL |
3547 | |
3548 | /* Fill in the remaining entries. */ | |
9771b263 | 3549 | FOR_EACH_VEC_ELT (*reg_known_value, i, val) |
9ff3c7ca SB |
3550 | { |
3551 | int regno = i + FIRST_PSEUDO_REGISTER; | |
3552 | if (! val) | |
3553 | set_reg_known_value (regno, regno_reg_rtx[regno]); | |
3554 | } | |
9ae8ffe7 | 3555 | |
e05e2395 MM |
3556 | /* Clean up. */ |
3557 | free (new_reg_base_value); | |
ec907dd8 | 3558 | new_reg_base_value = 0; |
d630245f | 3559 | sbitmap_free (reg_seen); |
9ae8ffe7 | 3560 | reg_seen = 0; |
0d446150 | 3561 | timevar_pop (TV_ALIAS_ANALYSIS); |
9ae8ffe7 JL |
3562 | } |
3563 | ||
61630b27 JJ |
3564 | /* Equate REG_BASE_VALUE (reg1) to REG_BASE_VALUE (reg2). |
3565 | Special API for var-tracking pass purposes. */ | |
3566 | ||
3567 | void | |
3568 | vt_equate_reg_base_value (const_rtx reg1, const_rtx reg2) | |
3569 | { | |
9771b263 | 3570 | (*reg_base_value)[REGNO (reg1)] = REG_BASE_VALUE (reg2); |
61630b27 JJ |
3571 | } |
3572 | ||
9ae8ffe7 | 3573 | void |
4682ae04 | 3574 | end_alias_analysis (void) |
9ae8ffe7 | 3575 | { |
c582d54a | 3576 | old_reg_base_value = reg_base_value; |
9771b263 | 3577 | vec_free (reg_known_value); |
9ff3c7ca | 3578 | sbitmap_free (reg_known_equiv_p); |
9ae8ffe7 | 3579 | } |
e2500fed | 3580 | |
3ecf9d13 JH |
3581 | void |
3582 | dump_alias_stats_in_alias_c (FILE *s) | |
3583 | { | |
3584 | fprintf (s, " TBAA oracle: %llu disambiguations %llu queries\n" | |
3585 | " %llu are in alias set 0\n" | |
3586 | " %llu queries asked about the same object\n" | |
3587 | " %llu queries asked about the same alias set\n" | |
3588 | " %llu access volatile\n" | |
6e042ef4 JH |
3589 | " %llu are dependent in the DAG\n" |
3590 | " %llu are aritificially in conflict with void *\n", | |
3ecf9d13 JH |
3591 | alias_stats.num_disambiguated, |
3592 | alias_stats.num_alias_zero + alias_stats.num_same_alias_set | |
3593 | + alias_stats.num_same_objects + alias_stats.num_volatile | |
6e042ef4 JH |
3594 | + alias_stats.num_dag + alias_stats.num_disambiguated |
3595 | + alias_stats.num_universal, | |
3ecf9d13 | 3596 | alias_stats.num_alias_zero, alias_stats.num_same_alias_set, |
6e042ef4 JH |
3597 | alias_stats.num_same_objects, alias_stats.num_volatile, |
3598 | alias_stats.num_dag, alias_stats.num_universal); | |
3ecf9d13 | 3599 | } |
e2500fed | 3600 | #include "gt-alias.h" |