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4ee9c684 | 1 | /* Alias analysis for trees. |
7cf0dbf3 | 2 | Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010 |
cfaf579d | 3 | Free Software Foundation, Inc. |
4ee9c684 | 4 | Contributed by Diego Novillo <dnovillo@redhat.com> |
5 | ||
6 | This file is part of GCC. | |
7 | ||
8 | GCC is free software; you can redistribute it and/or modify | |
9 | it under the terms of the GNU General Public License as published by | |
8c4c00c1 | 10 | the Free Software Foundation; either version 3, or (at your option) |
4ee9c684 | 11 | any later version. |
12 | ||
13 | GCC is distributed in the hope that it will be useful, | |
14 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | GNU General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU General Public License | |
8c4c00c1 | 19 | along with GCC; see the file COPYING3. If not see |
20 | <http://www.gnu.org/licenses/>. */ | |
4ee9c684 | 21 | |
22 | #include "config.h" | |
23 | #include "system.h" | |
24 | #include "coretypes.h" | |
25 | #include "tm.h" | |
26 | #include "tree.h" | |
4ee9c684 | 27 | #include "tm_p.h" |
4ee9c684 | 28 | #include "basic-block.h" |
29 | #include "timevar.h" | |
30 | #include "expr.h" | |
31 | #include "ggc.h" | |
32 | #include "langhooks.h" | |
33 | #include "flags.h" | |
34 | #include "function.h" | |
35 | #include "diagnostic.h" | |
ce084dfc | 36 | #include "tree-pretty-print.h" |
4ee9c684 | 37 | #include "tree-dump.h" |
75a70cf9 | 38 | #include "gimple.h" |
4ee9c684 | 39 | #include "tree-flow.h" |
40 | #include "tree-inline.h" | |
4ee9c684 | 41 | #include "tree-pass.h" |
42 | #include "convert.h" | |
43 | #include "params.h" | |
f7d118a9 | 44 | #include "ipa-type-escape.h" |
2be14d8b | 45 | #include "vec.h" |
a55dc2cd | 46 | #include "bitmap.h" |
05f3df98 | 47 | #include "vecprim.h" |
4fb5e5ca | 48 | #include "pointer-set.h" |
6cc9bd27 | 49 | #include "alloc-pool.h" |
dd277d48 | 50 | #include "tree-ssa-alias.h" |
a55dc2cd | 51 | |
dd277d48 | 52 | /* Broad overview of how alias analysis on gimple works: |
4fb5e5ca | 53 | |
dd277d48 | 54 | Statements clobbering or using memory are linked through the |
55 | virtual operand factored use-def chain. The virtual operand | |
56 | is unique per function, its symbol is accessible via gimple_vop (cfun). | |
57 | Virtual operands are used for efficiently walking memory statements | |
58 | in the gimple IL and are useful for things like value-numbering as | |
59 | a generation count for memory references. | |
339d7079 | 60 | |
dd277d48 | 61 | SSA_NAME pointers may have associated points-to information |
62 | accessible via the SSA_NAME_PTR_INFO macro. Flow-insensitive | |
63 | points-to information is (re-)computed by the TODO_rebuild_alias | |
64 | pass manager todo. Points-to information is also used for more | |
65 | precise tracking of call-clobbered and call-used variables and | |
66 | related disambiguations. | |
339d7079 | 67 | |
dd277d48 | 68 | This file contains functions for disambiguating memory references, |
69 | the so called alias-oracle and tools for walking of the gimple IL. | |
339d7079 | 70 | |
dd277d48 | 71 | The main alias-oracle entry-points are |
339d7079 | 72 | |
dd277d48 | 73 | bool stmt_may_clobber_ref_p (gimple, tree) |
339d7079 | 74 | |
dd277d48 | 75 | This function queries if a statement may invalidate (parts of) |
76 | the memory designated by the reference tree argument. | |
339d7079 | 77 | |
dd277d48 | 78 | bool ref_maybe_used_by_stmt_p (gimple, tree) |
339d7079 | 79 | |
dd277d48 | 80 | This function queries if a statement may need (parts of) the |
81 | memory designated by the reference tree argument. | |
339d7079 | 82 | |
dd277d48 | 83 | There are variants of these functions that only handle the call |
84 | part of a statement, call_may_clobber_ref_p and ref_maybe_used_by_call_p. | |
85 | Note that these do not disambiguate against a possible call lhs. | |
339d7079 | 86 | |
dd277d48 | 87 | bool refs_may_alias_p (tree, tree) |
339d7079 | 88 | |
dd277d48 | 89 | This function tries to disambiguate two reference trees. |
05931b00 | 90 | |
dd277d48 | 91 | bool ptr_deref_may_alias_global_p (tree) |
339d7079 | 92 | |
dd277d48 | 93 | This function queries if dereferencing a pointer variable may |
94 | alias global memory. | |
339d7079 | 95 | |
dd277d48 | 96 | More low-level disambiguators are available and documented in |
97 | this file. Low-level disambiguators dealing with points-to | |
98 | information are in tree-ssa-structalias.c. */ | |
339d7079 | 99 | |
339d7079 | 100 | |
dd277d48 | 101 | /* Query statistics for the different low-level disambiguators. |
102 | A high-level query may trigger multiple of them. */ | |
339d7079 | 103 | |
dd277d48 | 104 | static struct { |
105 | unsigned HOST_WIDE_INT refs_may_alias_p_may_alias; | |
106 | unsigned HOST_WIDE_INT refs_may_alias_p_no_alias; | |
107 | unsigned HOST_WIDE_INT ref_maybe_used_by_call_p_may_alias; | |
108 | unsigned HOST_WIDE_INT ref_maybe_used_by_call_p_no_alias; | |
109 | unsigned HOST_WIDE_INT call_may_clobber_ref_p_may_alias; | |
110 | unsigned HOST_WIDE_INT call_may_clobber_ref_p_no_alias; | |
111 | } alias_stats; | |
339d7079 | 112 | |
dd277d48 | 113 | void |
114 | dump_alias_stats (FILE *s) | |
115 | { | |
116 | fprintf (s, "\nAlias oracle query stats:\n"); | |
117 | fprintf (s, " refs_may_alias_p: " | |
118 | HOST_WIDE_INT_PRINT_DEC" disambiguations, " | |
119 | HOST_WIDE_INT_PRINT_DEC" queries\n", | |
120 | alias_stats.refs_may_alias_p_no_alias, | |
121 | alias_stats.refs_may_alias_p_no_alias | |
122 | + alias_stats.refs_may_alias_p_may_alias); | |
123 | fprintf (s, " ref_maybe_used_by_call_p: " | |
124 | HOST_WIDE_INT_PRINT_DEC" disambiguations, " | |
125 | HOST_WIDE_INT_PRINT_DEC" queries\n", | |
126 | alias_stats.ref_maybe_used_by_call_p_no_alias, | |
127 | alias_stats.refs_may_alias_p_no_alias | |
128 | + alias_stats.ref_maybe_used_by_call_p_may_alias); | |
129 | fprintf (s, " call_may_clobber_ref_p: " | |
130 | HOST_WIDE_INT_PRINT_DEC" disambiguations, " | |
131 | HOST_WIDE_INT_PRINT_DEC" queries\n", | |
132 | alias_stats.call_may_clobber_ref_p_no_alias, | |
133 | alias_stats.call_may_clobber_ref_p_no_alias | |
134 | + alias_stats.call_may_clobber_ref_p_may_alias); | |
135 | } | |
136 | ||
137 | ||
138 | /* Return true, if dereferencing PTR may alias with a global variable. */ | |
4ee9c684 | 139 | |
dd277d48 | 140 | bool |
141 | ptr_deref_may_alias_global_p (tree ptr) | |
4ee9c684 | 142 | { |
dd277d48 | 143 | struct ptr_info_def *pi; |
4fb5e5ca | 144 | |
dd277d48 | 145 | /* If we end up with a pointer constant here that may point |
146 | to global memory. */ | |
147 | if (TREE_CODE (ptr) != SSA_NAME) | |
148 | return true; | |
4ee9c684 | 149 | |
dd277d48 | 150 | pi = SSA_NAME_PTR_INFO (ptr); |
4ee9c684 | 151 | |
dd277d48 | 152 | /* If we do not have points-to information for this variable, |
153 | we have to punt. */ | |
154 | if (!pi) | |
155 | return true; | |
4ee9c684 | 156 | |
2a3ebafa | 157 | /* ??? This does not use TBAA to prune globals ptr may not access. */ |
dd277d48 | 158 | return pt_solution_includes_global (&pi->pt); |
4ee9c684 | 159 | } |
160 | ||
2a3ebafa | 161 | /* Return true if dereferencing PTR may alias DECL. |
162 | The caller is responsible for applying TBAA to see if PTR | |
163 | may access DECL at all. */ | |
4ee9c684 | 164 | |
dd277d48 | 165 | static bool |
166 | ptr_deref_may_alias_decl_p (tree ptr, tree decl) | |
4ee9c684 | 167 | { |
dd277d48 | 168 | struct ptr_info_def *pi; |
f7d118a9 | 169 | |
f85fb819 | 170 | gcc_assert ((TREE_CODE (ptr) == SSA_NAME |
171 | || TREE_CODE (ptr) == ADDR_EXPR | |
172 | || TREE_CODE (ptr) == INTEGER_CST) | |
173 | && (TREE_CODE (decl) == VAR_DECL | |
174 | || TREE_CODE (decl) == PARM_DECL | |
175 | || TREE_CODE (decl) == RESULT_DECL)); | |
2fd0b5dc | 176 | |
dd277d48 | 177 | /* Non-aliased variables can not be pointed to. */ |
178 | if (!may_be_aliased (decl)) | |
179 | return false; | |
2fd0b5dc | 180 | |
047fdd47 | 181 | /* ADDR_EXPR pointers either just offset another pointer or directly |
182 | specify the pointed-to set. */ | |
183 | if (TREE_CODE (ptr) == ADDR_EXPR) | |
184 | { | |
185 | tree base = get_base_address (TREE_OPERAND (ptr, 0)); | |
186 | if (base | |
187 | && INDIRECT_REF_P (base)) | |
188 | ptr = TREE_OPERAND (base, 0); | |
189 | else if (base | |
190 | && SSA_VAR_P (base)) | |
7f2d9047 | 191 | return base == decl; |
047fdd47 | 192 | else if (base |
193 | && CONSTANT_CLASS_P (base)) | |
194 | return false; | |
195 | else | |
196 | return true; | |
197 | } | |
198 | ||
f85fb819 | 199 | /* We can end up with dereferencing constant pointers. |
047fdd47 | 200 | Just bail out in this case. */ |
f85fb819 | 201 | if (TREE_CODE (ptr) == INTEGER_CST) |
047fdd47 | 202 | return true; |
203 | ||
dd277d48 | 204 | /* If we do not have useful points-to information for this pointer |
205 | we cannot disambiguate anything else. */ | |
206 | pi = SSA_NAME_PTR_INFO (ptr); | |
207 | if (!pi) | |
2fd0b5dc | 208 | return true; |
209 | ||
8bb76364 | 210 | /* If the decl can be used as a restrict tag and we have a restrict |
211 | pointer and that pointers points-to set doesn't contain this decl | |
212 | then they can't alias. */ | |
213 | if (DECL_RESTRICTED_P (decl) | |
214 | && TYPE_RESTRICT (TREE_TYPE (ptr)) | |
215 | && pi->pt.vars_contains_restrict) | |
1a981e1a | 216 | return bitmap_bit_p (pi->pt.vars, DECL_PT_UID (decl)); |
8bb76364 | 217 | |
dd277d48 | 218 | return pt_solution_includes (&pi->pt, decl); |
2fd0b5dc | 219 | } |
4ee9c684 | 220 | |
2a3ebafa | 221 | /* Return true if dereferenced PTR1 and PTR2 may alias. |
222 | The caller is responsible for applying TBAA to see if accesses | |
223 | through PTR1 and PTR2 may conflict at all. */ | |
4ee9c684 | 224 | |
dd277d48 | 225 | static bool |
226 | ptr_derefs_may_alias_p (tree ptr1, tree ptr2) | |
4ee9c684 | 227 | { |
dd277d48 | 228 | struct ptr_info_def *pi1, *pi2; |
4ee9c684 | 229 | |
f85fb819 | 230 | gcc_assert ((TREE_CODE (ptr1) == SSA_NAME |
231 | || TREE_CODE (ptr1) == ADDR_EXPR | |
232 | || TREE_CODE (ptr1) == INTEGER_CST) | |
233 | && (TREE_CODE (ptr2) == SSA_NAME | |
234 | || TREE_CODE (ptr2) == ADDR_EXPR | |
235 | || TREE_CODE (ptr2) == INTEGER_CST)); | |
236 | ||
047fdd47 | 237 | /* ADDR_EXPR pointers either just offset another pointer or directly |
238 | specify the pointed-to set. */ | |
239 | if (TREE_CODE (ptr1) == ADDR_EXPR) | |
240 | { | |
241 | tree base = get_base_address (TREE_OPERAND (ptr1, 0)); | |
242 | if (base | |
243 | && INDIRECT_REF_P (base)) | |
244 | ptr1 = TREE_OPERAND (base, 0); | |
245 | else if (base | |
246 | && SSA_VAR_P (base)) | |
247 | return ptr_deref_may_alias_decl_p (ptr2, base); | |
248 | else | |
249 | return true; | |
250 | } | |
251 | if (TREE_CODE (ptr2) == ADDR_EXPR) | |
252 | { | |
253 | tree base = get_base_address (TREE_OPERAND (ptr2, 0)); | |
254 | if (base | |
255 | && INDIRECT_REF_P (base)) | |
256 | ptr2 = TREE_OPERAND (base, 0); | |
257 | else if (base | |
258 | && SSA_VAR_P (base)) | |
259 | return ptr_deref_may_alias_decl_p (ptr1, base); | |
260 | else | |
261 | return true; | |
262 | } | |
263 | ||
f85fb819 | 264 | /* We can end up with dereferencing constant pointers. |
047fdd47 | 265 | Just bail out in this case. */ |
f85fb819 | 266 | if (TREE_CODE (ptr1) == INTEGER_CST |
267 | || TREE_CODE (ptr2) == INTEGER_CST) | |
dd277d48 | 268 | return true; |
4ee9c684 | 269 | |
dd277d48 | 270 | /* We may end up with two empty points-to solutions for two same pointers. |
271 | In this case we still want to say both pointers alias, so shortcut | |
272 | that here. */ | |
273 | if (ptr1 == ptr2) | |
274 | return true; | |
81d08033 | 275 | |
dd277d48 | 276 | /* If we do not have useful points-to information for either pointer |
277 | we cannot disambiguate anything else. */ | |
278 | pi1 = SSA_NAME_PTR_INFO (ptr1); | |
279 | pi2 = SSA_NAME_PTR_INFO (ptr2); | |
280 | if (!pi1 || !pi2) | |
281 | return true; | |
81d08033 | 282 | |
1c1f1bc0 | 283 | /* If both pointers are restrict-qualified try to disambiguate |
284 | with restrict information. */ | |
285 | if (TYPE_RESTRICT (TREE_TYPE (ptr1)) | |
286 | && TYPE_RESTRICT (TREE_TYPE (ptr2)) | |
287 | && !pt_solutions_same_restrict_base (&pi1->pt, &pi2->pt)) | |
288 | return false; | |
289 | ||
2a3ebafa | 290 | /* ??? This does not use TBAA to prune decls from the intersection |
291 | that not both pointers may access. */ | |
dd277d48 | 292 | return pt_solutions_intersect (&pi1->pt, &pi2->pt); |
81d08033 | 293 | } |
294 | ||
047fdd47 | 295 | /* Return true if dereferencing PTR may alias *REF. |
296 | The caller is responsible for applying TBAA to see if PTR | |
297 | may access *REF at all. */ | |
298 | ||
299 | static bool | |
300 | ptr_deref_may_alias_ref_p_1 (tree ptr, ao_ref *ref) | |
301 | { | |
302 | tree base = ao_ref_base (ref); | |
303 | ||
304 | if (INDIRECT_REF_P (base)) | |
305 | return ptr_derefs_may_alias_p (ptr, TREE_OPERAND (base, 0)); | |
306 | else if (SSA_VAR_P (base)) | |
307 | return ptr_deref_may_alias_decl_p (ptr, base); | |
308 | ||
309 | return true; | |
310 | } | |
311 | ||
4ee9c684 | 312 | |
313 | /* Dump alias information on FILE. */ | |
314 | ||
315 | void | |
316 | dump_alias_info (FILE *file) | |
317 | { | |
318 | size_t i; | |
319 | const char *funcname | |
5135beeb | 320 | = lang_hooks.decl_printable_name (current_function_decl, 2); |
a55dc2cd | 321 | referenced_var_iterator rvi; |
322 | tree var; | |
4ee9c684 | 323 | |
dd277d48 | 324 | fprintf (file, "\n\nAlias information for %s\n\n", funcname); |
81d08033 | 325 | |
326 | fprintf (file, "Aliased symbols\n\n"); | |
48e1416a | 327 | |
a55dc2cd | 328 | FOR_EACH_REFERENCED_VAR (var, rvi) |
81d08033 | 329 | { |
81d08033 | 330 | if (may_be_aliased (var)) |
331 | dump_variable (file, var); | |
332 | } | |
333 | ||
7f81b5ee | 334 | fprintf (file, "\nCall clobber information\n"); |
335 | ||
336 | fprintf (file, "\nESCAPED"); | |
337 | dump_points_to_solution (file, &cfun->gimple_df->escaped); | |
7f81b5ee | 338 | |
339 | fprintf (file, "\n\nFlow-insensitive points-to information\n\n"); | |
81d08033 | 340 | |
81d08033 | 341 | for (i = 1; i < num_ssa_names; i++) |
342 | { | |
343 | tree ptr = ssa_name (i); | |
a48b1470 | 344 | struct ptr_info_def *pi; |
48e1416a | 345 | |
dd277d48 | 346 | if (ptr == NULL_TREE |
347 | || SSA_NAME_IN_FREE_LIST (ptr)) | |
a48b1470 | 348 | continue; |
349 | ||
350 | pi = SSA_NAME_PTR_INFO (ptr); | |
dd277d48 | 351 | if (pi) |
81d08033 | 352 | dump_points_to_info_for (file, ptr); |
353 | } | |
4ee9c684 | 354 | |
4ee9c684 | 355 | fprintf (file, "\n"); |
356 | } | |
357 | ||
358 | ||
359 | /* Dump alias information on stderr. */ | |
360 | ||
4b987fac | 361 | DEBUG_FUNCTION void |
4ee9c684 | 362 | debug_alias_info (void) |
363 | { | |
364 | dump_alias_info (stderr); | |
365 | } | |
366 | ||
367 | ||
786d45db | 368 | /* Return the alias information associated with pointer T. It creates a |
369 | new instance if none existed. */ | |
370 | ||
3276c83b | 371 | struct ptr_info_def * |
786d45db | 372 | get_ptr_info (tree t) |
373 | { | |
374 | struct ptr_info_def *pi; | |
375 | ||
8c0963c4 | 376 | gcc_assert (POINTER_TYPE_P (TREE_TYPE (t))); |
786d45db | 377 | |
378 | pi = SSA_NAME_PTR_INFO (t); | |
379 | if (pi == NULL) | |
380 | { | |
43959b95 | 381 | pi = GGC_CNEW (struct ptr_info_def); |
dd277d48 | 382 | pt_solution_reset (&pi->pt); |
786d45db | 383 | SSA_NAME_PTR_INFO (t) = pi; |
384 | } | |
385 | ||
386 | return pi; | |
387 | } | |
388 | ||
7f81b5ee | 389 | /* Dump the points-to set *PT into FILE. */ |
4ee9c684 | 390 | |
d793732c | 391 | void |
7f81b5ee | 392 | dump_points_to_solution (FILE *file, struct pt_solution *pt) |
4ee9c684 | 393 | { |
7f81b5ee | 394 | if (pt->anything) |
395 | fprintf (file, ", points-to anything"); | |
4ee9c684 | 396 | |
7f81b5ee | 397 | if (pt->nonlocal) |
398 | fprintf (file, ", points-to non-local"); | |
4ee9c684 | 399 | |
7f81b5ee | 400 | if (pt->escaped) |
401 | fprintf (file, ", points-to escaped"); | |
402 | ||
1a981e1a | 403 | if (pt->ipa_escaped) |
404 | fprintf (file, ", points-to unit escaped"); | |
405 | ||
7f81b5ee | 406 | if (pt->null) |
407 | fprintf (file, ", points-to NULL"); | |
408 | ||
409 | if (pt->vars) | |
4ee9c684 | 410 | { |
7f81b5ee | 411 | fprintf (file, ", points-to vars: "); |
412 | dump_decl_set (file, pt->vars); | |
413 | if (pt->vars_contains_global) | |
414 | fprintf (file, " (includes global vars)"); | |
1a981e1a | 415 | if (pt->vars_contains_restrict) |
416 | fprintf (file, " (includes restrict tags)"); | |
7f81b5ee | 417 | } |
418 | } | |
4ee9c684 | 419 | |
7f81b5ee | 420 | /* Dump points-to information for SSA_NAME PTR into FILE. */ |
4ee9c684 | 421 | |
7f81b5ee | 422 | void |
423 | dump_points_to_info_for (FILE *file, tree ptr) | |
424 | { | |
425 | struct ptr_info_def *pi = SSA_NAME_PTR_INFO (ptr); | |
4ee9c684 | 426 | |
7f81b5ee | 427 | print_generic_expr (file, ptr, dump_flags); |
1e1a4c8c | 428 | |
7f81b5ee | 429 | if (pi) |
430 | dump_points_to_solution (file, &pi->pt); | |
431 | else | |
432 | fprintf (file, ", points-to anything"); | |
4ee9c684 | 433 | |
434 | fprintf (file, "\n"); | |
435 | } | |
436 | ||
437 | ||
d793732c | 438 | /* Dump points-to information for VAR into stderr. */ |
439 | ||
4b987fac | 440 | DEBUG_FUNCTION void |
d793732c | 441 | debug_points_to_info_for (tree var) |
442 | { | |
443 | dump_points_to_info_for (stderr, var); | |
444 | } | |
445 | ||
3918bd18 | 446 | |
447 | /* Initializes the alias-oracle reference representation *R from REF. */ | |
448 | ||
449 | void | |
450 | ao_ref_init (ao_ref *r, tree ref) | |
451 | { | |
452 | r->ref = ref; | |
453 | r->base = NULL_TREE; | |
454 | r->offset = 0; | |
455 | r->size = -1; | |
456 | r->max_size = -1; | |
457 | r->ref_alias_set = -1; | |
458 | r->base_alias_set = -1; | |
459 | } | |
460 | ||
461 | /* Returns the base object of the memory reference *REF. */ | |
462 | ||
463 | tree | |
464 | ao_ref_base (ao_ref *ref) | |
465 | { | |
466 | if (ref->base) | |
467 | return ref->base; | |
468 | ref->base = get_ref_base_and_extent (ref->ref, &ref->offset, &ref->size, | |
469 | &ref->max_size); | |
470 | return ref->base; | |
471 | } | |
472 | ||
473 | /* Returns the base object alias set of the memory reference *REF. */ | |
474 | ||
475 | static alias_set_type ATTRIBUTE_UNUSED | |
476 | ao_ref_base_alias_set (ao_ref *ref) | |
477 | { | |
478 | if (ref->base_alias_set != -1) | |
479 | return ref->base_alias_set; | |
480 | ref->base_alias_set = get_alias_set (ao_ref_base (ref)); | |
481 | return ref->base_alias_set; | |
482 | } | |
483 | ||
484 | /* Returns the reference alias set of the memory reference *REF. */ | |
485 | ||
486 | alias_set_type | |
487 | ao_ref_alias_set (ao_ref *ref) | |
488 | { | |
489 | if (ref->ref_alias_set != -1) | |
490 | return ref->ref_alias_set; | |
491 | ref->ref_alias_set = get_alias_set (ref->ref); | |
492 | return ref->ref_alias_set; | |
493 | } | |
494 | ||
134899ac | 495 | /* Init an alias-oracle reference representation from a gimple pointer |
496 | PTR and a gimple size SIZE in bytes. If SIZE is NULL_TREE the the | |
497 | size is assumed to be unknown. The access is assumed to be only | |
498 | to or after of the pointer target, not before it. */ | |
499 | ||
500 | void | |
501 | ao_ref_init_from_ptr_and_size (ao_ref *ref, tree ptr, tree size) | |
502 | { | |
503 | HOST_WIDE_INT t1, t2; | |
504 | ref->ref = NULL_TREE; | |
505 | if (TREE_CODE (ptr) == ADDR_EXPR) | |
506 | ref->base = get_ref_base_and_extent (TREE_OPERAND (ptr, 0), | |
507 | &ref->offset, &t1, &t2); | |
508 | else | |
509 | { | |
510 | ref->base = build1 (INDIRECT_REF, char_type_node, ptr); | |
511 | ref->offset = 0; | |
512 | } | |
513 | if (size | |
514 | && host_integerp (size, 0) | |
515 | && TREE_INT_CST_LOW (size) * 8 / 8 == TREE_INT_CST_LOW (size)) | |
516 | ref->max_size = ref->size = TREE_INT_CST_LOW (size) * 8; | |
517 | else | |
518 | ref->max_size = ref->size = -1; | |
519 | ref->ref_alias_set = 0; | |
520 | ref->base_alias_set = 0; | |
521 | } | |
522 | ||
dd277d48 | 523 | /* Return 1 if TYPE1 and TYPE2 are to be considered equivalent for the |
524 | purpose of TBAA. Return 0 if they are distinct and -1 if we cannot | |
525 | decide. */ | |
d793732c | 526 | |
dd277d48 | 527 | static inline int |
528 | same_type_for_tbaa (tree type1, tree type2) | |
529 | { | |
530 | type1 = TYPE_MAIN_VARIANT (type1); | |
531 | type2 = TYPE_MAIN_VARIANT (type2); | |
4ee9c684 | 532 | |
dd277d48 | 533 | /* If we would have to do structural comparison bail out. */ |
534 | if (TYPE_STRUCTURAL_EQUALITY_P (type1) | |
535 | || TYPE_STRUCTURAL_EQUALITY_P (type2)) | |
536 | return -1; | |
537 | ||
538 | /* Compare the canonical types. */ | |
539 | if (TYPE_CANONICAL (type1) == TYPE_CANONICAL (type2)) | |
540 | return 1; | |
541 | ||
4b4d1513 | 542 | /* ??? Array types are not properly unified in all cases as we have |
dd277d48 | 543 | spurious changes in the index types for example. Removing this |
544 | causes all sorts of problems with the Fortran frontend. */ | |
545 | if (TREE_CODE (type1) == ARRAY_TYPE | |
546 | && TREE_CODE (type2) == ARRAY_TYPE) | |
547 | return -1; | |
548 | ||
102bfc9c | 549 | /* ??? In Ada, an lvalue of an unconstrained type can be used to access an |
550 | object of one of its constrained subtypes, e.g. when a function with an | |
551 | unconstrained parameter passed by reference is called on an object and | |
552 | inlined. But, even in the case of a fixed size, type and subtypes are | |
553 | not equivalent enough as to share the same TYPE_CANONICAL, since this | |
554 | would mean that conversions between them are useless, whereas they are | |
555 | not (e.g. type and subtypes can have different modes). So, in the end, | |
556 | they are only guaranteed to have the same alias set. */ | |
557 | if (get_alias_set (type1) == get_alias_set (type2)) | |
4b4d1513 | 558 | return -1; |
559 | ||
dd277d48 | 560 | /* The types are known to be not equal. */ |
561 | return 0; | |
562 | } | |
563 | ||
564 | /* Determine if the two component references REF1 and REF2 which are | |
565 | based on access types TYPE1 and TYPE2 and of which at least one is based | |
ac30e3b2 | 566 | on an indirect reference may alias. REF2 is the only one that can |
567 | be a decl in which case REF2_IS_DECL is true. | |
568 | REF1_ALIAS_SET, BASE1_ALIAS_SET, REF2_ALIAS_SET and BASE2_ALIAS_SET | |
569 | are the respective alias sets. */ | |
dd277d48 | 570 | |
571 | static bool | |
a42ce2cc | 572 | aliasing_component_refs_p (tree ref1, tree type1, |
ac30e3b2 | 573 | alias_set_type ref1_alias_set, |
574 | alias_set_type base1_alias_set, | |
a42ce2cc | 575 | HOST_WIDE_INT offset1, HOST_WIDE_INT max_size1, |
576 | tree ref2, tree type2, | |
ac30e3b2 | 577 | alias_set_type ref2_alias_set, |
578 | alias_set_type base2_alias_set, | |
579 | HOST_WIDE_INT offset2, HOST_WIDE_INT max_size2, | |
580 | bool ref2_is_decl) | |
dd277d48 | 581 | { |
582 | /* If one reference is a component references through pointers try to find a | |
583 | common base and apply offset based disambiguation. This handles | |
584 | for example | |
585 | struct A { int i; int j; } *q; | |
586 | struct B { struct A a; int k; } *p; | |
587 | disambiguating q->i and p->a.j. */ | |
588 | tree *refp; | |
589 | int same_p; | |
590 | ||
591 | /* Now search for the type1 in the access path of ref2. This | |
592 | would be a common base for doing offset based disambiguation on. */ | |
bc3c318e | 593 | refp = &ref2; |
dd277d48 | 594 | while (handled_component_p (*refp) |
595 | && same_type_for_tbaa (TREE_TYPE (*refp), type1) == 0) | |
596 | refp = &TREE_OPERAND (*refp, 0); | |
597 | same_p = same_type_for_tbaa (TREE_TYPE (*refp), type1); | |
598 | /* If we couldn't compare types we have to bail out. */ | |
599 | if (same_p == -1) | |
600 | return true; | |
601 | else if (same_p == 1) | |
602 | { | |
603 | HOST_WIDE_INT offadj, sztmp, msztmp; | |
604 | get_ref_base_and_extent (*refp, &offadj, &sztmp, &msztmp); | |
605 | offset2 -= offadj; | |
606 | return ranges_overlap_p (offset1, max_size1, offset2, max_size2); | |
607 | } | |
608 | /* If we didn't find a common base, try the other way around. */ | |
bc3c318e | 609 | refp = &ref1; |
dd277d48 | 610 | while (handled_component_p (*refp) |
611 | && same_type_for_tbaa (TREE_TYPE (*refp), type2) == 0) | |
612 | refp = &TREE_OPERAND (*refp, 0); | |
613 | same_p = same_type_for_tbaa (TREE_TYPE (*refp), type2); | |
614 | /* If we couldn't compare types we have to bail out. */ | |
615 | if (same_p == -1) | |
616 | return true; | |
617 | else if (same_p == 1) | |
618 | { | |
619 | HOST_WIDE_INT offadj, sztmp, msztmp; | |
620 | get_ref_base_and_extent (*refp, &offadj, &sztmp, &msztmp); | |
621 | offset1 -= offadj; | |
622 | return ranges_overlap_p (offset1, max_size1, offset2, max_size2); | |
623 | } | |
ac30e3b2 | 624 | |
4b4d1513 | 625 | /* If we have two type access paths B1.path1 and B2.path2 they may |
ac30e3b2 | 626 | only alias if either B1 is in B2.path2 or B2 is in B1.path1. |
627 | But we can still have a path that goes B1.path1...B2.path2 with | |
628 | a part that we do not see. So we can only disambiguate now | |
629 | if there is no B2 in the tail of path1 and no B1 on the | |
630 | tail of path2. */ | |
631 | if (base1_alias_set == ref2_alias_set | |
632 | || alias_set_subset_of (base1_alias_set, ref2_alias_set)) | |
633 | return true; | |
634 | /* If this is ptr vs. decl then we know there is no ptr ... decl path. */ | |
635 | if (!ref2_is_decl) | |
636 | return (base2_alias_set == ref1_alias_set | |
637 | || alias_set_subset_of (base2_alias_set, ref1_alias_set)); | |
4b4d1513 | 638 | return false; |
dd277d48 | 639 | } |
640 | ||
641 | /* Return true if two memory references based on the variables BASE1 | |
077ad5ad | 642 | and BASE2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and |
643 | [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. */ | |
dd277d48 | 644 | |
645 | static bool | |
646 | decl_refs_may_alias_p (tree base1, | |
647 | HOST_WIDE_INT offset1, HOST_WIDE_INT max_size1, | |
648 | tree base2, | |
649 | HOST_WIDE_INT offset2, HOST_WIDE_INT max_size2) | |
4ee9c684 | 650 | { |
dd277d48 | 651 | gcc_assert (SSA_VAR_P (base1) && SSA_VAR_P (base2)); |
4ee9c684 | 652 | |
dd277d48 | 653 | /* If both references are based on different variables, they cannot alias. */ |
7f2d9047 | 654 | if (base1 != base2) |
dd277d48 | 655 | return false; |
4ee9c684 | 656 | |
dd277d48 | 657 | /* If both references are based on the same variable, they cannot alias if |
658 | the accesses do not overlap. */ | |
659 | return ranges_overlap_p (offset1, max_size1, offset2, max_size2); | |
660 | } | |
661 | ||
662 | /* Return true if an indirect reference based on *PTR1 constrained | |
077ad5ad | 663 | to [OFFSET1, OFFSET1 + MAX_SIZE1) may alias a variable based on BASE2 |
664 | constrained to [OFFSET2, OFFSET2 + MAX_SIZE2). *PTR1 and BASE2 have | |
dd277d48 | 665 | the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1 |
666 | in which case they are computed on-demand. REF1 and REF2 | |
667 | if non-NULL are the complete memory reference trees. */ | |
668 | ||
669 | static bool | |
670 | indirect_ref_may_alias_decl_p (tree ref1, tree ptr1, | |
671 | HOST_WIDE_INT offset1, HOST_WIDE_INT max_size1, | |
ac30e3b2 | 672 | alias_set_type ref1_alias_set, |
dd277d48 | 673 | alias_set_type base1_alias_set, |
674 | tree ref2, tree base2, | |
675 | HOST_WIDE_INT offset2, HOST_WIDE_INT max_size2, | |
ac30e3b2 | 676 | alias_set_type ref2_alias_set, |
dd277d48 | 677 | alias_set_type base2_alias_set) |
678 | { | |
679 | /* If only one reference is based on a variable, they cannot alias if | |
680 | the pointer access is beyond the extent of the variable access. | |
681 | (the pointer base cannot validly point to an offset less than zero | |
682 | of the variable). | |
683 | They also cannot alias if the pointer may not point to the decl. */ | |
684 | if (max_size2 != -1 | |
685 | && !ranges_overlap_p (offset1, max_size1, 0, offset2 + max_size2)) | |
686 | return false; | |
687 | if (!ptr_deref_may_alias_decl_p (ptr1, base2)) | |
688 | return false; | |
689 | ||
690 | /* Disambiguations that rely on strict aliasing rules follow. */ | |
691 | if (!flag_strict_aliasing) | |
692 | return true; | |
693 | ||
694 | /* If the alias set for a pointer access is zero all bets are off. */ | |
695 | if (base1_alias_set == -1) | |
696 | base1_alias_set = get_deref_alias_set (ptr1); | |
697 | if (base1_alias_set == 0) | |
698 | return true; | |
699 | if (base2_alias_set == -1) | |
700 | base2_alias_set = get_alias_set (base2); | |
701 | ||
702 | /* If both references are through the same type, they do not alias | |
703 | if the accesses do not overlap. This does extra disambiguation | |
704 | for mixed/pointer accesses but requires strict aliasing. */ | |
705 | if (same_type_for_tbaa (TREE_TYPE (TREE_TYPE (ptr1)), | |
706 | TREE_TYPE (base2)) == 1) | |
707 | return ranges_overlap_p (offset1, max_size1, offset2, max_size2); | |
708 | ||
709 | /* The only way to access a variable is through a pointer dereference | |
710 | of the same alias set or a subset of it. */ | |
711 | if (base1_alias_set != base2_alias_set | |
712 | && !alias_set_subset_of (base1_alias_set, base2_alias_set)) | |
713 | return false; | |
714 | ||
715 | /* Do access-path based disambiguation. */ | |
716 | if (ref1 && ref2 | |
717 | && handled_component_p (ref1) | |
718 | && handled_component_p (ref2)) | |
a42ce2cc | 719 | return aliasing_component_refs_p (ref1, TREE_TYPE (TREE_TYPE (ptr1)), |
ac30e3b2 | 720 | ref1_alias_set, base1_alias_set, |
a42ce2cc | 721 | offset1, max_size1, |
722 | ref2, TREE_TYPE (base2), | |
ac30e3b2 | 723 | ref2_alias_set, base2_alias_set, |
724 | offset2, max_size2, true); | |
dd277d48 | 725 | |
726 | return true; | |
727 | } | |
728 | ||
729 | /* Return true if two indirect references based on *PTR1 | |
077ad5ad | 730 | and *PTR2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and |
731 | [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. *PTR1 and *PTR2 have | |
dd277d48 | 732 | the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1 |
733 | in which case they are computed on-demand. REF1 and REF2 | |
734 | if non-NULL are the complete memory reference trees. */ | |
735 | ||
736 | static bool | |
737 | indirect_refs_may_alias_p (tree ref1, tree ptr1, | |
738 | HOST_WIDE_INT offset1, HOST_WIDE_INT max_size1, | |
ac30e3b2 | 739 | alias_set_type ref1_alias_set, |
dd277d48 | 740 | alias_set_type base1_alias_set, |
741 | tree ref2, tree ptr2, | |
742 | HOST_WIDE_INT offset2, HOST_WIDE_INT max_size2, | |
ac30e3b2 | 743 | alias_set_type ref2_alias_set, |
dd277d48 | 744 | alias_set_type base2_alias_set) |
745 | { | |
746 | /* If both bases are based on pointers they cannot alias if they may not | |
747 | point to the same memory object or if they point to the same object | |
748 | and the accesses do not overlap. */ | |
749 | if (operand_equal_p (ptr1, ptr2, 0)) | |
750 | return ranges_overlap_p (offset1, max_size1, offset2, max_size2); | |
751 | if (!ptr_derefs_may_alias_p (ptr1, ptr2)) | |
752 | return false; | |
753 | ||
754 | /* Disambiguations that rely on strict aliasing rules follow. */ | |
755 | if (!flag_strict_aliasing) | |
756 | return true; | |
757 | ||
758 | /* If the alias set for a pointer access is zero all bets are off. */ | |
759 | if (base1_alias_set == -1) | |
760 | base1_alias_set = get_deref_alias_set (ptr1); | |
761 | if (base1_alias_set == 0) | |
762 | return true; | |
763 | if (base2_alias_set == -1) | |
764 | base2_alias_set = get_deref_alias_set (ptr2); | |
765 | if (base2_alias_set == 0) | |
766 | return true; | |
767 | ||
768 | /* If both references are through the same type, they do not alias | |
769 | if the accesses do not overlap. This does extra disambiguation | |
770 | for mixed/pointer accesses but requires strict aliasing. */ | |
771 | if (same_type_for_tbaa (TREE_TYPE (TREE_TYPE (ptr1)), | |
772 | TREE_TYPE (TREE_TYPE (ptr2))) == 1) | |
773 | return ranges_overlap_p (offset1, max_size1, offset2, max_size2); | |
774 | ||
775 | /* Do type-based disambiguation. */ | |
776 | if (base1_alias_set != base2_alias_set | |
777 | && !alias_sets_conflict_p (base1_alias_set, base2_alias_set)) | |
778 | return false; | |
779 | ||
780 | /* Do access-path based disambiguation. */ | |
781 | if (ref1 && ref2 | |
782 | && handled_component_p (ref1) | |
783 | && handled_component_p (ref2)) | |
a42ce2cc | 784 | return aliasing_component_refs_p (ref1, TREE_TYPE (TREE_TYPE (ptr1)), |
ac30e3b2 | 785 | ref1_alias_set, base1_alias_set, |
a42ce2cc | 786 | offset1, max_size1, |
787 | ref2, TREE_TYPE (TREE_TYPE (ptr2)), | |
ac30e3b2 | 788 | ref2_alias_set, base2_alias_set, |
789 | offset2, max_size2, false); | |
dd277d48 | 790 | |
791 | return true; | |
792 | } | |
793 | ||
794 | /* Return true, if the two memory references REF1 and REF2 may alias. */ | |
795 | ||
3a443843 | 796 | bool |
3918bd18 | 797 | refs_may_alias_p_1 (ao_ref *ref1, ao_ref *ref2, bool tbaa_p) |
dd277d48 | 798 | { |
799 | tree base1, base2; | |
800 | HOST_WIDE_INT offset1 = 0, offset2 = 0; | |
dd277d48 | 801 | HOST_WIDE_INT max_size1 = -1, max_size2 = -1; |
802 | bool var1_p, var2_p, ind1_p, ind2_p; | |
2a3ebafa | 803 | alias_set_type set; |
dd277d48 | 804 | |
3918bd18 | 805 | gcc_assert ((!ref1->ref |
806 | || SSA_VAR_P (ref1->ref) | |
807 | || handled_component_p (ref1->ref) | |
808 | || INDIRECT_REF_P (ref1->ref) | |
119147d1 | 809 | || TREE_CODE (ref1->ref) == TARGET_MEM_REF |
810 | || TREE_CODE (ref1->ref) == CONST_DECL) | |
3918bd18 | 811 | && (!ref2->ref |
812 | || SSA_VAR_P (ref2->ref) | |
813 | || handled_component_p (ref2->ref) | |
814 | || INDIRECT_REF_P (ref2->ref) | |
119147d1 | 815 | || TREE_CODE (ref2->ref) == TARGET_MEM_REF |
816 | || TREE_CODE (ref2->ref) == CONST_DECL)); | |
dd277d48 | 817 | |
dd277d48 | 818 | /* Decompose the references into their base objects and the access. */ |
3918bd18 | 819 | base1 = ao_ref_base (ref1); |
820 | offset1 = ref1->offset; | |
3918bd18 | 821 | max_size1 = ref1->max_size; |
822 | base2 = ao_ref_base (ref2); | |
823 | offset2 = ref2->offset; | |
3918bd18 | 824 | max_size2 = ref2->max_size; |
dd277d48 | 825 | |
826 | /* We can end up with registers or constants as bases for example from | |
827 | *D.1663_44 = VIEW_CONVERT_EXPR<struct DB_LSN>(__tmp$B0F64_59); | |
828 | which is seen as a struct copy. */ | |
829 | if (TREE_CODE (base1) == SSA_NAME | |
dd277d48 | 830 | || TREE_CODE (base2) == SSA_NAME |
119147d1 | 831 | || TREE_CODE (base1) == CONST_DECL |
832 | || TREE_CODE (base2) == CONST_DECL | |
9b973aa6 | 833 | || is_gimple_min_invariant (base1) |
f85fb819 | 834 | || is_gimple_min_invariant (base2)) |
dd277d48 | 835 | return false; |
836 | ||
ceefbccc | 837 | /* We can end up refering to code via function decls. As we likely |
838 | do not properly track code aliases conservatively bail out. */ | |
839 | if (TREE_CODE (base1) == FUNCTION_DECL | |
840 | || TREE_CODE (base2) == FUNCTION_DECL) | |
841 | return true; | |
842 | ||
090a8c65 | 843 | /* Defer to simple offset based disambiguation if we have |
844 | references based on two decls. Do this before defering to | |
845 | TBAA to handle must-alias cases in conformance with the | |
846 | GCC extension of allowing type-punning through unions. */ | |
dd277d48 | 847 | var1_p = SSA_VAR_P (base1); |
848 | var2_p = SSA_VAR_P (base2); | |
dd277d48 | 849 | if (var1_p && var2_p) |
850 | return decl_refs_may_alias_p (base1, offset1, max_size1, | |
851 | base2, offset2, max_size2); | |
090a8c65 | 852 | |
67817f0f | 853 | ind1_p = INDIRECT_REF_P (base1); |
854 | ind2_p = INDIRECT_REF_P (base2); | |
855 | /* Canonicalize the pointer-vs-decl case. */ | |
856 | if (ind1_p && var2_p) | |
857 | { | |
858 | HOST_WIDE_INT tmp1; | |
859 | tree tmp2; | |
860 | ao_ref *tmp3; | |
861 | tmp1 = offset1; offset1 = offset2; offset2 = tmp1; | |
862 | tmp1 = max_size1; max_size1 = max_size2; max_size2 = tmp1; | |
863 | tmp2 = base1; base1 = base2; base2 = tmp2; | |
864 | tmp3 = ref1; ref1 = ref2; ref2 = tmp3; | |
865 | var1_p = true; | |
866 | ind1_p = false; | |
867 | var2_p = false; | |
868 | ind2_p = true; | |
869 | } | |
870 | ||
871 | /* If we are about to disambiguate pointer-vs-decl try harder to | |
872 | see must-aliases and give leeway to some invalid cases. | |
873 | This covers a pretty minimal set of cases only and does not | |
874 | when called from the RTL oracle. It handles cases like | |
875 | ||
876 | int i = 1; | |
877 | return *(float *)&i; | |
878 | ||
879 | and also fixes gfortran.dg/lto/pr40725. */ | |
880 | if (var1_p && ind2_p | |
881 | && cfun | |
882 | && gimple_in_ssa_p (cfun) | |
883 | && TREE_CODE (TREE_OPERAND (base2, 0)) == SSA_NAME) | |
884 | { | |
885 | gimple def_stmt = SSA_NAME_DEF_STMT (TREE_OPERAND (base2, 0)); | |
886 | while (is_gimple_assign (def_stmt) | |
887 | && (gimple_assign_rhs_code (def_stmt) == SSA_NAME | |
888 | || CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt)))) | |
889 | { | |
890 | tree rhs = gimple_assign_rhs1 (def_stmt); | |
891 | HOST_WIDE_INT offset, size, max_size; | |
892 | ||
893 | /* Look through SSA name copies and pointer conversions. */ | |
894 | if (TREE_CODE (rhs) == SSA_NAME | |
895 | && POINTER_TYPE_P (TREE_TYPE (rhs))) | |
896 | { | |
897 | def_stmt = SSA_NAME_DEF_STMT (rhs); | |
898 | continue; | |
899 | } | |
900 | if (TREE_CODE (rhs) != ADDR_EXPR) | |
901 | break; | |
902 | ||
903 | /* If the pointer is defined as an address based on a decl | |
904 | use plain offset disambiguation and ignore TBAA. */ | |
905 | rhs = TREE_OPERAND (rhs, 0); | |
906 | rhs = get_ref_base_and_extent (rhs, &offset, &size, &max_size); | |
907 | if (SSA_VAR_P (rhs)) | |
908 | { | |
909 | base2 = rhs; | |
910 | offset2 += offset; | |
911 | if (size != max_size | |
912 | || max_size == -1) | |
913 | max_size2 = -1; | |
914 | return decl_refs_may_alias_p (base1, offset1, max_size1, | |
915 | base2, offset2, max_size2); | |
916 | } | |
917 | ||
918 | /* Do not continue looking through &p->x to limit time | |
919 | complexity. */ | |
920 | break; | |
921 | } | |
922 | } | |
923 | ||
090a8c65 | 924 | /* First defer to TBAA if possible. */ |
2a3ebafa | 925 | if (tbaa_p |
926 | && flag_strict_aliasing | |
3918bd18 | 927 | && !alias_sets_conflict_p (ao_ref_alias_set (ref1), |
928 | ao_ref_alias_set (ref2))) | |
090a8c65 | 929 | return false; |
930 | ||
931 | /* If one reference is a TARGET_MEM_REF weird things are allowed. Still | |
932 | TBAA disambiguation based on the access type is possible, so bail | |
933 | out only after that check. */ | |
3918bd18 | 934 | if ((ref1->ref && TREE_CODE (ref1->ref) == TARGET_MEM_REF) |
935 | || (ref2->ref && TREE_CODE (ref2->ref) == TARGET_MEM_REF)) | |
090a8c65 | 936 | return true; |
937 | ||
938 | /* Dispatch to the pointer-vs-decl or pointer-vs-pointer disambiguators. */ | |
2a3ebafa | 939 | set = tbaa_p ? -1 : 0; |
090a8c65 | 940 | if (var1_p && ind2_p) |
3918bd18 | 941 | return indirect_ref_may_alias_decl_p (ref2->ref, TREE_OPERAND (base2, 0), |
ac30e3b2 | 942 | offset2, max_size2, |
943 | ao_ref_alias_set (ref2), set, | |
3918bd18 | 944 | ref1->ref, base1, |
ac30e3b2 | 945 | offset1, max_size1, |
946 | ao_ref_alias_set (ref1), set); | |
dd277d48 | 947 | else if (ind1_p && ind2_p) |
3918bd18 | 948 | return indirect_refs_may_alias_p (ref1->ref, TREE_OPERAND (base1, 0), |
ac30e3b2 | 949 | offset1, max_size1, |
950 | ao_ref_alias_set (ref1), set, | |
3918bd18 | 951 | ref2->ref, TREE_OPERAND (base2, 0), |
ac30e3b2 | 952 | offset2, max_size2, |
953 | ao_ref_alias_set (ref2), set); | |
dd277d48 | 954 | |
955 | gcc_unreachable (); | |
956 | } | |
957 | ||
958 | bool | |
959 | refs_may_alias_p (tree ref1, tree ref2) | |
960 | { | |
3918bd18 | 961 | ao_ref r1, r2; |
962 | bool res; | |
963 | ao_ref_init (&r1, ref1); | |
964 | ao_ref_init (&r2, ref2); | |
965 | res = refs_may_alias_p_1 (&r1, &r2, true); | |
dd277d48 | 966 | if (res) |
967 | ++alias_stats.refs_may_alias_p_may_alias; | |
968 | else | |
969 | ++alias_stats.refs_may_alias_p_no_alias; | |
970 | return res; | |
971 | } | |
972 | ||
2a3ebafa | 973 | /* Returns true if there is a anti-dependence for the STORE that |
974 | executes after the LOAD. */ | |
975 | ||
976 | bool | |
977 | refs_anti_dependent_p (tree load, tree store) | |
978 | { | |
3918bd18 | 979 | ao_ref r1, r2; |
980 | ao_ref_init (&r1, load); | |
981 | ao_ref_init (&r2, store); | |
982 | return refs_may_alias_p_1 (&r1, &r2, false); | |
2a3ebafa | 983 | } |
984 | ||
985 | /* Returns true if there is a output dependence for the stores | |
986 | STORE1 and STORE2. */ | |
987 | ||
988 | bool | |
989 | refs_output_dependent_p (tree store1, tree store2) | |
990 | { | |
3918bd18 | 991 | ao_ref r1, r2; |
992 | ao_ref_init (&r1, store1); | |
993 | ao_ref_init (&r2, store2); | |
994 | return refs_may_alias_p_1 (&r1, &r2, false); | |
2a3ebafa | 995 | } |
dd277d48 | 996 | |
997 | /* If the call CALL may use the memory reference REF return true, | |
998 | otherwise return false. */ | |
999 | ||
1000 | static bool | |
134899ac | 1001 | ref_maybe_used_by_call_p_1 (gimple call, ao_ref *ref) |
dd277d48 | 1002 | { |
047fdd47 | 1003 | tree base, callee; |
dd277d48 | 1004 | unsigned i; |
1005 | int flags = gimple_call_flags (call); | |
1006 | ||
1007 | /* Const functions without a static chain do not implicitly use memory. */ | |
1008 | if (!gimple_call_chain (call) | |
1009 | && (flags & (ECF_CONST|ECF_NOVOPS))) | |
1010 | goto process_args; | |
1011 | ||
134899ac | 1012 | base = ao_ref_base (ref); |
917f08fa | 1013 | if (!base) |
dd277d48 | 1014 | return true; |
1015 | ||
09347e88 | 1016 | /* If the reference is based on a decl that is not aliased the call |
1017 | cannot possibly use it. */ | |
1018 | if (DECL_P (base) | |
1019 | && !may_be_aliased (base) | |
7f7f16d4 | 1020 | /* But local statics can be used through recursion. */ |
1021 | && !is_global_var (base)) | |
09347e88 | 1022 | goto process_args; |
1023 | ||
047fdd47 | 1024 | callee = gimple_call_fndecl (call); |
1025 | ||
1026 | /* Handle those builtin functions explicitly that do not act as | |
1027 | escape points. See tree-ssa-structalias.c:find_func_aliases | |
1028 | for the list of builtins we might need to handle here. */ | |
1029 | if (callee != NULL_TREE | |
1030 | && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL) | |
1031 | switch (DECL_FUNCTION_CODE (callee)) | |
1032 | { | |
1033 | /* All the following functions clobber memory pointed to by | |
1034 | their first argument. */ | |
1035 | case BUILT_IN_STRCPY: | |
1036 | case BUILT_IN_STRNCPY: | |
047fdd47 | 1037 | case BUILT_IN_MEMCPY: |
1038 | case BUILT_IN_MEMMOVE: | |
1039 | case BUILT_IN_MEMPCPY: | |
1040 | case BUILT_IN_STPCPY: | |
1041 | case BUILT_IN_STPNCPY: | |
1042 | case BUILT_IN_STRCAT: | |
1043 | case BUILT_IN_STRNCAT: | |
1044 | { | |
134899ac | 1045 | ao_ref dref; |
1046 | tree size = NULL_TREE; | |
1047 | if (gimple_call_num_args (call) == 3) | |
1048 | size = gimple_call_arg (call, 2); | |
1049 | ao_ref_init_from_ptr_and_size (&dref, | |
1050 | gimple_call_arg (call, 1), | |
1051 | size); | |
1052 | return refs_may_alias_p_1 (&dref, ref, false); | |
047fdd47 | 1053 | } |
119147d1 | 1054 | case BUILT_IN_BCOPY: |
1055 | { | |
1056 | ao_ref dref; | |
1057 | tree size = gimple_call_arg (call, 2); | |
1058 | ao_ref_init_from_ptr_and_size (&dref, | |
1059 | gimple_call_arg (call, 0), | |
1060 | size); | |
1061 | return refs_may_alias_p_1 (&dref, ref, false); | |
1062 | } | |
09d9c774 | 1063 | /* The following builtins do not read from memory. */ |
1064 | case BUILT_IN_FREE: | |
0d3ca08e | 1065 | case BUILT_IN_MALLOC: |
4ef43bbd | 1066 | case BUILT_IN_CALLOC: |
09d9c774 | 1067 | case BUILT_IN_MEMSET: |
1068 | case BUILT_IN_FREXP: | |
1069 | case BUILT_IN_FREXPF: | |
1070 | case BUILT_IN_FREXPL: | |
1071 | case BUILT_IN_GAMMA_R: | |
1072 | case BUILT_IN_GAMMAF_R: | |
1073 | case BUILT_IN_GAMMAL_R: | |
1074 | case BUILT_IN_LGAMMA_R: | |
1075 | case BUILT_IN_LGAMMAF_R: | |
1076 | case BUILT_IN_LGAMMAL_R: | |
1077 | case BUILT_IN_MODF: | |
1078 | case BUILT_IN_MODFF: | |
1079 | case BUILT_IN_MODFL: | |
1080 | case BUILT_IN_REMQUO: | |
1081 | case BUILT_IN_REMQUOF: | |
1082 | case BUILT_IN_REMQUOL: | |
1083 | case BUILT_IN_SINCOS: | |
1084 | case BUILT_IN_SINCOSF: | |
1085 | case BUILT_IN_SINCOSL: | |
1086 | return false; | |
1087 | ||
047fdd47 | 1088 | default: |
1089 | /* Fallthru to general call handling. */; | |
1090 | } | |
1091 | ||
dd277d48 | 1092 | /* Check if base is a global static variable that is not read |
1093 | by the function. */ | |
1094 | if (TREE_CODE (base) == VAR_DECL | |
d97be713 | 1095 | && TREE_STATIC (base)) |
4ee9c684 | 1096 | { |
dd277d48 | 1097 | bitmap not_read; |
1098 | ||
1099 | if (callee != NULL_TREE | |
1100 | && (not_read | |
1101 | = ipa_reference_get_not_read_global (cgraph_node (callee))) | |
1102 | && bitmap_bit_p (not_read, DECL_UID (base))) | |
1103 | goto process_args; | |
4ee9c684 | 1104 | } |
1105 | ||
cb245216 | 1106 | /* Check if the base variable is call-used. */ |
1107 | if (DECL_P (base)) | |
4ee9c684 | 1108 | { |
cb245216 | 1109 | if (pt_solution_includes (gimple_call_use_set (call), base)) |
dd277d48 | 1110 | return true; |
1111 | } | |
cb245216 | 1112 | else if (INDIRECT_REF_P (base) |
1113 | && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME) | |
dd277d48 | 1114 | { |
cb245216 | 1115 | struct ptr_info_def *pi = SSA_NAME_PTR_INFO (TREE_OPERAND (base, 0)); |
1116 | if (!pi) | |
1117 | return true; | |
917f08fa | 1118 | |
cb245216 | 1119 | if (pt_solutions_intersect (gimple_call_use_set (call), &pi->pt)) |
dd277d48 | 1120 | return true; |
1121 | } | |
cb245216 | 1122 | else |
1123 | return true; | |
dd277d48 | 1124 | |
1125 | /* Inspect call arguments for passed-by-value aliases. */ | |
1126 | process_args: | |
1127 | for (i = 0; i < gimple_call_num_args (call); ++i) | |
1128 | { | |
1129 | tree op = gimple_call_arg (call, i); | |
8ce86007 | 1130 | int flags = gimple_call_arg_flags (call, i); |
1131 | ||
1132 | if (flags & EAF_UNUSED) | |
1133 | continue; | |
dd277d48 | 1134 | |
dd277d48 | 1135 | if (TREE_CODE (op) == WITH_SIZE_EXPR) |
1136 | op = TREE_OPERAND (op, 0); | |
4ee9c684 | 1137 | |
dd277d48 | 1138 | if (TREE_CODE (op) != SSA_NAME |
134899ac | 1139 | && !is_gimple_min_invariant (op)) |
1140 | { | |
1141 | ao_ref r; | |
1142 | ao_ref_init (&r, op); | |
1143 | if (refs_may_alias_p_1 (&r, ref, true)) | |
1144 | return true; | |
1145 | } | |
4ee9c684 | 1146 | } |
1147 | ||
dd277d48 | 1148 | return false; |
1149 | } | |
1150 | ||
1151 | static bool | |
1152 | ref_maybe_used_by_call_p (gimple call, tree ref) | |
1153 | { | |
134899ac | 1154 | ao_ref r; |
1155 | bool res; | |
1156 | ao_ref_init (&r, ref); | |
1157 | res = ref_maybe_used_by_call_p_1 (call, &r); | |
dd277d48 | 1158 | if (res) |
1159 | ++alias_stats.ref_maybe_used_by_call_p_may_alias; | |
1160 | else | |
1161 | ++alias_stats.ref_maybe_used_by_call_p_no_alias; | |
1162 | return res; | |
4ee9c684 | 1163 | } |
1164 | ||
1165 | ||
dd277d48 | 1166 | /* If the statement STMT may use the memory reference REF return |
1167 | true, otherwise return false. */ | |
4ee9c684 | 1168 | |
dd277d48 | 1169 | bool |
1170 | ref_maybe_used_by_stmt_p (gimple stmt, tree ref) | |
4ee9c684 | 1171 | { |
dd277d48 | 1172 | if (is_gimple_assign (stmt)) |
1173 | { | |
1174 | tree rhs; | |
1175 | ||
1176 | /* All memory assign statements are single. */ | |
1177 | if (!gimple_assign_single_p (stmt)) | |
1178 | return false; | |
1179 | ||
1180 | rhs = gimple_assign_rhs1 (stmt); | |
1181 | if (is_gimple_reg (rhs) | |
1182 | || is_gimple_min_invariant (rhs) | |
1183 | || gimple_assign_rhs_code (stmt) == CONSTRUCTOR) | |
1184 | return false; | |
1185 | ||
1186 | return refs_may_alias_p (rhs, ref); | |
1187 | } | |
1188 | else if (is_gimple_call (stmt)) | |
1189 | return ref_maybe_used_by_call_p (stmt, ref); | |
1190 | ||
1191 | return true; | |
4ee9c684 | 1192 | } |
1193 | ||
dd277d48 | 1194 | /* If the call in statement CALL may clobber the memory reference REF |
1195 | return true, otherwise return false. */ | |
4ee9c684 | 1196 | |
dd277d48 | 1197 | static bool |
3918bd18 | 1198 | call_may_clobber_ref_p_1 (gimple call, ao_ref *ref) |
4ee9c684 | 1199 | { |
7f7f16d4 | 1200 | tree base; |
047fdd47 | 1201 | tree callee; |
dd277d48 | 1202 | |
1203 | /* If the call is pure or const it cannot clobber anything. */ | |
1204 | if (gimple_call_flags (call) | |
1205 | & (ECF_PURE|ECF_CONST|ECF_LOOPING_CONST_OR_PURE|ECF_NOVOPS)) | |
1206 | return false; | |
1207 | ||
3918bd18 | 1208 | base = ao_ref_base (ref); |
dd277d48 | 1209 | if (!base) |
1210 | return true; | |
1211 | ||
1212 | if (TREE_CODE (base) == SSA_NAME | |
1213 | || CONSTANT_CLASS_P (base)) | |
1214 | return false; | |
1215 | ||
09347e88 | 1216 | /* If the reference is based on a decl that is not aliased the call |
1217 | cannot possibly clobber it. */ | |
1218 | if (DECL_P (base) | |
1219 | && !may_be_aliased (base) | |
7f7f16d4 | 1220 | /* But local non-readonly statics can be modified through recursion |
1221 | or the call may implement a threading barrier which we must | |
1222 | treat as may-def. */ | |
09347e88 | 1223 | && (TREE_READONLY (base) |
7f7f16d4 | 1224 | || !is_global_var (base))) |
09347e88 | 1225 | return false; |
1226 | ||
047fdd47 | 1227 | callee = gimple_call_fndecl (call); |
1228 | ||
1229 | /* Handle those builtin functions explicitly that do not act as | |
1230 | escape points. See tree-ssa-structalias.c:find_func_aliases | |
1231 | for the list of builtins we might need to handle here. */ | |
1232 | if (callee != NULL_TREE | |
1233 | && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL) | |
1234 | switch (DECL_FUNCTION_CODE (callee)) | |
1235 | { | |
1236 | /* All the following functions clobber memory pointed to by | |
1237 | their first argument. */ | |
1238 | case BUILT_IN_STRCPY: | |
1239 | case BUILT_IN_STRNCPY: | |
047fdd47 | 1240 | case BUILT_IN_MEMCPY: |
1241 | case BUILT_IN_MEMMOVE: | |
1242 | case BUILT_IN_MEMPCPY: | |
1243 | case BUILT_IN_STPCPY: | |
1244 | case BUILT_IN_STPNCPY: | |
1245 | case BUILT_IN_STRCAT: | |
1246 | case BUILT_IN_STRNCAT: | |
134899ac | 1247 | case BUILT_IN_MEMSET: |
047fdd47 | 1248 | { |
134899ac | 1249 | ao_ref dref; |
1250 | tree size = NULL_TREE; | |
1251 | if (gimple_call_num_args (call) == 3) | |
1252 | size = gimple_call_arg (call, 2); | |
1253 | ao_ref_init_from_ptr_and_size (&dref, | |
1254 | gimple_call_arg (call, 0), | |
1255 | size); | |
1256 | return refs_may_alias_p_1 (&dref, ref, false); | |
047fdd47 | 1257 | } |
119147d1 | 1258 | case BUILT_IN_BCOPY: |
1259 | { | |
1260 | ao_ref dref; | |
1261 | tree size = gimple_call_arg (call, 2); | |
1262 | ao_ref_init_from_ptr_and_size (&dref, | |
1263 | gimple_call_arg (call, 1), | |
1264 | size); | |
1265 | return refs_may_alias_p_1 (&dref, ref, false); | |
1266 | } | |
0d3ca08e | 1267 | /* Allocating memory does not have any side-effects apart from |
1268 | being the definition point for the pointer. */ | |
1269 | case BUILT_IN_MALLOC: | |
4ef43bbd | 1270 | case BUILT_IN_CALLOC: |
1271 | /* Unix98 specifies that errno is set on allocation failure. | |
1272 | Until we properly can track the errno location assume it | |
a29c5f9c | 1273 | is not a local decl but external or anonymous storage in |
1274 | a different translation unit. Also assume it is of | |
1275 | type int as required by the standard. */ | |
1276 | if (flag_errno_math | |
1277 | && TREE_TYPE (base) == integer_type_node) | |
4ef43bbd | 1278 | { |
1279 | struct ptr_info_def *pi; | |
a29c5f9c | 1280 | if (DECL_P (base) |
1281 | && !TREE_STATIC (base)) | |
1282 | return true; | |
1283 | else if (INDIRECT_REF_P (base) | |
1284 | && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME | |
1285 | && (pi = SSA_NAME_PTR_INFO (TREE_OPERAND (base, 0)))) | |
4ef43bbd | 1286 | return pi->pt.anything || pi->pt.nonlocal; |
1287 | } | |
0d3ca08e | 1288 | return false; |
047fdd47 | 1289 | /* Freeing memory kills the pointed-to memory. More importantly |
1290 | the call has to serve as a barrier for moving loads and stores | |
134899ac | 1291 | across it. */ |
047fdd47 | 1292 | case BUILT_IN_FREE: |
047fdd47 | 1293 | { |
1294 | tree ptr = gimple_call_arg (call, 0); | |
1295 | return ptr_deref_may_alias_ref_p_1 (ptr, ref); | |
1296 | } | |
047fdd47 | 1297 | case BUILT_IN_GAMMA_R: |
1298 | case BUILT_IN_GAMMAF_R: | |
1299 | case BUILT_IN_GAMMAL_R: | |
1300 | case BUILT_IN_LGAMMA_R: | |
1301 | case BUILT_IN_LGAMMAF_R: | |
1302 | case BUILT_IN_LGAMMAL_R: | |
09d9c774 | 1303 | { |
1304 | tree out = gimple_call_arg (call, 1); | |
1305 | if (ptr_deref_may_alias_ref_p_1 (out, ref)) | |
1306 | return true; | |
1307 | if (flag_errno_math) | |
1308 | break; | |
1309 | return false; | |
1310 | } | |
1311 | case BUILT_IN_FREXP: | |
1312 | case BUILT_IN_FREXPF: | |
1313 | case BUILT_IN_FREXPL: | |
047fdd47 | 1314 | case BUILT_IN_MODF: |
1315 | case BUILT_IN_MODFF: | |
1316 | case BUILT_IN_MODFL: | |
1317 | { | |
1318 | tree out = gimple_call_arg (call, 1); | |
1319 | return ptr_deref_may_alias_ref_p_1 (out, ref); | |
1320 | } | |
1321 | case BUILT_IN_REMQUO: | |
1322 | case BUILT_IN_REMQUOF: | |
1323 | case BUILT_IN_REMQUOL: | |
1324 | { | |
1325 | tree out = gimple_call_arg (call, 2); | |
09d9c774 | 1326 | if (ptr_deref_may_alias_ref_p_1 (out, ref)) |
1327 | return true; | |
1328 | if (flag_errno_math) | |
1329 | break; | |
1330 | return false; | |
047fdd47 | 1331 | } |
1332 | case BUILT_IN_SINCOS: | |
1333 | case BUILT_IN_SINCOSF: | |
1334 | case BUILT_IN_SINCOSL: | |
1335 | { | |
1336 | tree sin = gimple_call_arg (call, 1); | |
1337 | tree cos = gimple_call_arg (call, 2); | |
1338 | return (ptr_deref_may_alias_ref_p_1 (sin, ref) | |
1339 | || ptr_deref_may_alias_ref_p_1 (cos, ref)); | |
1340 | } | |
1341 | default: | |
1342 | /* Fallthru to general call handling. */; | |
1343 | } | |
1344 | ||
dd277d48 | 1345 | /* Check if base is a global static variable that is not written |
1346 | by the function. */ | |
047fdd47 | 1347 | if (callee != NULL_TREE |
1348 | && TREE_CODE (base) == VAR_DECL | |
d97be713 | 1349 | && TREE_STATIC (base)) |
4ee9c684 | 1350 | { |
dd277d48 | 1351 | bitmap not_written; |
0eaf9bd7 | 1352 | |
047fdd47 | 1353 | if ((not_written |
1354 | = ipa_reference_get_not_written_global (cgraph_node (callee))) | |
dd277d48 | 1355 | && bitmap_bit_p (not_written, DECL_UID (base))) |
1356 | return false; | |
4ee9c684 | 1357 | } |
4ee9c684 | 1358 | |
cb245216 | 1359 | /* Check if the base variable is call-clobbered. */ |
dd277d48 | 1360 | if (DECL_P (base)) |
cb245216 | 1361 | return pt_solution_includes (gimple_call_clobber_set (call), base); |
917f08fa | 1362 | else if (INDIRECT_REF_P (base) |
1363 | && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME) | |
1364 | { | |
1365 | struct ptr_info_def *pi = SSA_NAME_PTR_INFO (TREE_OPERAND (base, 0)); | |
1366 | if (!pi) | |
1367 | return true; | |
1368 | ||
cb245216 | 1369 | return pt_solutions_intersect (gimple_call_clobber_set (call), &pi->pt); |
917f08fa | 1370 | } |
4ee9c684 | 1371 | |
dd277d48 | 1372 | return true; |
1373 | } | |
4ee9c684 | 1374 | |
4debfcfc | 1375 | /* If the call in statement CALL may clobber the memory reference REF |
1376 | return true, otherwise return false. */ | |
1377 | ||
1378 | bool | |
dd277d48 | 1379 | call_may_clobber_ref_p (gimple call, tree ref) |
4ee9c684 | 1380 | { |
3918bd18 | 1381 | bool res; |
1382 | ao_ref r; | |
1383 | ao_ref_init (&r, ref); | |
1384 | res = call_may_clobber_ref_p_1 (call, &r); | |
dd277d48 | 1385 | if (res) |
1386 | ++alias_stats.call_may_clobber_ref_p_may_alias; | |
1387 | else | |
1388 | ++alias_stats.call_may_clobber_ref_p_no_alias; | |
1389 | return res; | |
4ee9c684 | 1390 | } |
94e6573f | 1391 | |
dd277d48 | 1392 | |
1393 | /* If the statement STMT may clobber the memory reference REF return true, | |
1394 | otherwise return false. */ | |
94e6573f | 1395 | |
1396 | bool | |
3918bd18 | 1397 | stmt_may_clobber_ref_p_1 (gimple stmt, ao_ref *ref) |
94e6573f | 1398 | { |
dd277d48 | 1399 | if (is_gimple_call (stmt)) |
1400 | { | |
1401 | tree lhs = gimple_call_lhs (stmt); | |
1402 | if (lhs | |
3918bd18 | 1403 | && !is_gimple_reg (lhs)) |
1404 | { | |
1405 | ao_ref r; | |
1406 | ao_ref_init (&r, lhs); | |
1407 | if (refs_may_alias_p_1 (ref, &r, true)) | |
1408 | return true; | |
1409 | } | |
94e6573f | 1410 | |
3918bd18 | 1411 | return call_may_clobber_ref_p_1 (stmt, ref); |
dd277d48 | 1412 | } |
1413 | else if (is_gimple_assign (stmt)) | |
3918bd18 | 1414 | { |
1415 | ao_ref r; | |
1416 | ao_ref_init (&r, gimple_assign_lhs (stmt)); | |
1417 | return refs_may_alias_p_1 (ref, &r, true); | |
1418 | } | |
dd277d48 | 1419 | else if (gimple_code (stmt) == GIMPLE_ASM) |
94e6573f | 1420 | return true; |
1421 | ||
6329636b | 1422 | return false; |
94e6573f | 1423 | } |
2be14d8b | 1424 | |
3918bd18 | 1425 | bool |
1426 | stmt_may_clobber_ref_p (gimple stmt, tree ref) | |
1427 | { | |
1428 | ao_ref r; | |
1429 | ao_ref_init (&r, ref); | |
1430 | return stmt_may_clobber_ref_p_1 (stmt, &r); | |
1431 | } | |
1432 | ||
1433 | ||
dd277d48 | 1434 | /* Walk the virtual use-def chain of VUSE until hitting the virtual operand |
1435 | TARGET or a statement clobbering the memory reference REF in which | |
1436 | case false is returned. The walk starts with VUSE, one argument of PHI. */ | |
1437 | ||
1438 | static bool | |
3918bd18 | 1439 | maybe_skip_until (gimple phi, tree target, ao_ref *ref, |
1440 | tree vuse, bitmap *visited) | |
ac926412 | 1441 | { |
dd277d48 | 1442 | if (!*visited) |
1443 | *visited = BITMAP_ALLOC (NULL); | |
ac926412 | 1444 | |
dd277d48 | 1445 | bitmap_set_bit (*visited, SSA_NAME_VERSION (PHI_RESULT (phi))); |
1446 | ||
1447 | /* Walk until we hit the target. */ | |
1448 | while (vuse != target) | |
ac926412 | 1449 | { |
dd277d48 | 1450 | gimple def_stmt = SSA_NAME_DEF_STMT (vuse); |
1451 | /* Recurse for PHI nodes. */ | |
1452 | if (gimple_code (def_stmt) == GIMPLE_PHI) | |
1453 | { | |
1454 | /* An already visited PHI node ends the walk successfully. */ | |
1455 | if (bitmap_bit_p (*visited, SSA_NAME_VERSION (PHI_RESULT (def_stmt)))) | |
1456 | return true; | |
1457 | vuse = get_continuation_for_phi (def_stmt, ref, visited); | |
1458 | if (!vuse) | |
1459 | return false; | |
1460 | continue; | |
1461 | } | |
1462 | /* A clobbering statement or the end of the IL ends it failing. */ | |
1463 | else if (gimple_nop_p (def_stmt) | |
3918bd18 | 1464 | || stmt_may_clobber_ref_p_1 (def_stmt, ref)) |
dd277d48 | 1465 | return false; |
1466 | vuse = gimple_vuse (def_stmt); | |
ac926412 | 1467 | } |
dd277d48 | 1468 | return true; |
1469 | } | |
ac926412 | 1470 | |
dd277d48 | 1471 | /* Starting from a PHI node for the virtual operand of the memory reference |
1472 | REF find a continuation virtual operand that allows to continue walking | |
1473 | statements dominating PHI skipping only statements that cannot possibly | |
1474 | clobber REF. Returns NULL_TREE if no suitable virtual operand can | |
1475 | be found. */ | |
1476 | ||
7814d418 | 1477 | tree |
3918bd18 | 1478 | get_continuation_for_phi (gimple phi, ao_ref *ref, bitmap *visited) |
dd277d48 | 1479 | { |
1480 | unsigned nargs = gimple_phi_num_args (phi); | |
1481 | ||
1482 | /* Through a single-argument PHI we can simply look through. */ | |
1483 | if (nargs == 1) | |
1484 | return PHI_ARG_DEF (phi, 0); | |
1485 | ||
1486 | /* For two arguments try to skip non-aliasing code until we hit | |
1487 | the phi argument definition that dominates the other one. */ | |
1488 | if (nargs == 2) | |
ac926412 | 1489 | { |
dd277d48 | 1490 | tree arg0 = PHI_ARG_DEF (phi, 0); |
1491 | tree arg1 = PHI_ARG_DEF (phi, 1); | |
1492 | gimple def0 = SSA_NAME_DEF_STMT (arg0); | |
1493 | gimple def1 = SSA_NAME_DEF_STMT (arg1); | |
7814d418 | 1494 | tree common_vuse; |
dd277d48 | 1495 | |
1496 | if (arg0 == arg1) | |
1497 | return arg0; | |
1498 | else if (gimple_nop_p (def0) | |
1499 | || (!gimple_nop_p (def1) | |
1500 | && dominated_by_p (CDI_DOMINATORS, | |
1501 | gimple_bb (def1), gimple_bb (def0)))) | |
1502 | { | |
1503 | if (maybe_skip_until (phi, arg0, ref, arg1, visited)) | |
1504 | return arg0; | |
1505 | } | |
1506 | else if (gimple_nop_p (def1) | |
1507 | || dominated_by_p (CDI_DOMINATORS, | |
1508 | gimple_bb (def0), gimple_bb (def1))) | |
1509 | { | |
1510 | if (maybe_skip_until (phi, arg1, ref, arg0, visited)) | |
1511 | return arg1; | |
1512 | } | |
7814d418 | 1513 | /* Special case of a diamond: |
1514 | MEM_1 = ... | |
1515 | goto (cond) ? L1 : L2 | |
1516 | L1: store1 = ... #MEM_2 = vuse(MEM_1) | |
1517 | goto L3 | |
1518 | L2: store2 = ... #MEM_3 = vuse(MEM_1) | |
1519 | L3: MEM_4 = PHI<MEM_2, MEM_3> | |
1520 | We were called with the PHI at L3, MEM_2 and MEM_3 don't | |
1521 | dominate each other, but still we can easily skip this PHI node | |
1522 | if we recognize that the vuse MEM operand is the same for both, | |
1523 | and that we can skip both statements (they don't clobber us). | |
1524 | This is still linear. Don't use maybe_skip_until, that might | |
1525 | potentially be slow. */ | |
1526 | else if ((common_vuse = gimple_vuse (def0)) | |
1527 | && common_vuse == gimple_vuse (def1)) | |
1528 | { | |
1529 | if (!stmt_may_clobber_ref_p_1 (def0, ref) | |
1530 | && !stmt_may_clobber_ref_p_1 (def1, ref)) | |
1531 | return common_vuse; | |
1532 | } | |
ac926412 | 1533 | } |
dd277d48 | 1534 | |
1535 | return NULL_TREE; | |
ac926412 | 1536 | } |
516849c7 | 1537 | |
dd277d48 | 1538 | /* Based on the memory reference REF and its virtual use VUSE call |
1539 | WALKER for each virtual use that is equivalent to VUSE, including VUSE | |
1540 | itself. That is, for each virtual use for which its defining statement | |
1541 | does not clobber REF. | |
e683de6d | 1542 | |
dd277d48 | 1543 | WALKER is called with REF, the current virtual use and DATA. If |
1544 | WALKER returns non-NULL the walk stops and its result is returned. | |
1545 | At the end of a non-successful walk NULL is returned. | |
3857274c | 1546 | |
d8021dea | 1547 | TRANSLATE if non-NULL is called with a pointer to REF, the virtual |
1548 | use which definition is a statement that may clobber REF and DATA. | |
1549 | If TRANSLATE returns (void *)-1 the walk stops and NULL is returned. | |
1550 | If TRANSLATE returns non-NULL the walk stops and its result is returned. | |
1551 | If TRANSLATE returns NULL the walk continues and TRANSLATE is supposed | |
1552 | to adjust REF and *DATA to make that valid. | |
1553 | ||
dd277d48 | 1554 | TODO: Cache the vector of equivalent vuses per ref, vuse pair. */ |
1555 | ||
1556 | void * | |
3918bd18 | 1557 | walk_non_aliased_vuses (ao_ref *ref, tree vuse, |
1558 | void *(*walker)(ao_ref *, tree, void *), | |
1559 | void *(*translate)(ao_ref *, tree, void *), void *data) | |
3857274c | 1560 | { |
dd277d48 | 1561 | bitmap visited = NULL; |
1562 | void *res; | |
1563 | ||
02c74b9b | 1564 | timevar_push (TV_ALIAS_STMT_WALK); |
1565 | ||
dd277d48 | 1566 | do |
1567 | { | |
1568 | gimple def_stmt; | |
3857274c | 1569 | |
02c74b9b | 1570 | /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */ |
dd277d48 | 1571 | res = (*walker) (ref, vuse, data); |
1572 | if (res) | |
1573 | break; | |
3857274c | 1574 | |
dd277d48 | 1575 | def_stmt = SSA_NAME_DEF_STMT (vuse); |
1576 | if (gimple_nop_p (def_stmt)) | |
1577 | break; | |
1578 | else if (gimple_code (def_stmt) == GIMPLE_PHI) | |
1579 | vuse = get_continuation_for_phi (def_stmt, ref, &visited); | |
1580 | else | |
1581 | { | |
3918bd18 | 1582 | if (stmt_may_clobber_ref_p_1 (def_stmt, ref)) |
d8021dea | 1583 | { |
1584 | if (!translate) | |
1585 | break; | |
3918bd18 | 1586 | res = (*translate) (ref, vuse, data); |
d8021dea | 1587 | /* Failed lookup and translation. */ |
1588 | if (res == (void *)-1) | |
1589 | { | |
1590 | res = NULL; | |
1591 | break; | |
1592 | } | |
1593 | /* Lookup succeeded. */ | |
1594 | else if (res != NULL) | |
1595 | break; | |
1596 | /* Translation succeeded, continue walking. */ | |
1597 | } | |
dd277d48 | 1598 | vuse = gimple_vuse (def_stmt); |
1599 | } | |
1600 | } | |
1601 | while (vuse); | |
ac926412 | 1602 | |
dd277d48 | 1603 | if (visited) |
1604 | BITMAP_FREE (visited); | |
ac926412 | 1605 | |
02c74b9b | 1606 | timevar_pop (TV_ALIAS_STMT_WALK); |
1607 | ||
dd277d48 | 1608 | return res; |
3857274c | 1609 | } |
1610 | ||
604eef2c | 1611 | |
dd277d48 | 1612 | /* Based on the memory reference REF call WALKER for each vdef which |
1613 | defining statement may clobber REF, starting with VDEF. If REF | |
1614 | is NULL_TREE, each defining statement is visited. | |
1615 | ||
1616 | WALKER is called with REF, the current vdef and DATA. If WALKER | |
1617 | returns true the walk is stopped, otherwise it continues. | |
1618 | ||
1619 | At PHI nodes walk_aliased_vdefs forks into one walk for reach | |
1620 | PHI argument (but only one walk continues on merge points), the | |
1621 | return value is true if any of the walks was successful. | |
1622 | ||
1623 | The function returns the number of statements walked. */ | |
604eef2c | 1624 | |
1625 | static unsigned int | |
1daead67 | 1626 | walk_aliased_vdefs_1 (ao_ref *ref, tree vdef, |
1627 | bool (*walker)(ao_ref *, tree, void *), void *data, | |
dd277d48 | 1628 | bitmap *visited, unsigned int cnt) |
604eef2c | 1629 | { |
dd277d48 | 1630 | do |
1631 | { | |
1632 | gimple def_stmt = SSA_NAME_DEF_STMT (vdef); | |
604eef2c | 1633 | |
dd277d48 | 1634 | if (*visited |
1635 | && !bitmap_set_bit (*visited, SSA_NAME_VERSION (vdef))) | |
1636 | return cnt; | |
1637 | ||
1638 | if (gimple_nop_p (def_stmt)) | |
1639 | return cnt; | |
1640 | else if (gimple_code (def_stmt) == GIMPLE_PHI) | |
1641 | { | |
1642 | unsigned i; | |
1643 | if (!*visited) | |
1644 | *visited = BITMAP_ALLOC (NULL); | |
1645 | for (i = 0; i < gimple_phi_num_args (def_stmt); ++i) | |
1646 | cnt += walk_aliased_vdefs_1 (ref, gimple_phi_arg_def (def_stmt, i), | |
1647 | walker, data, visited, 0); | |
1648 | return cnt; | |
1649 | } | |
1650 | ||
02c74b9b | 1651 | /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */ |
dd277d48 | 1652 | cnt++; |
1653 | if ((!ref | |
1daead67 | 1654 | || stmt_may_clobber_ref_p_1 (def_stmt, ref)) |
dd277d48 | 1655 | && (*walker) (ref, vdef, data)) |
1656 | return cnt; | |
1657 | ||
1658 | vdef = gimple_vuse (def_stmt); | |
1659 | } | |
1660 | while (1); | |
604eef2c | 1661 | } |
1662 | ||
dd277d48 | 1663 | unsigned int |
1daead67 | 1664 | walk_aliased_vdefs (ao_ref *ref, tree vdef, |
1665 | bool (*walker)(ao_ref *, tree, void *), void *data, | |
dd277d48 | 1666 | bitmap *visited) |
df3f0669 | 1667 | { |
dd277d48 | 1668 | bitmap local_visited = NULL; |
1669 | unsigned int ret; | |
1670 | ||
02c74b9b | 1671 | timevar_push (TV_ALIAS_STMT_WALK); |
1672 | ||
dd277d48 | 1673 | ret = walk_aliased_vdefs_1 (ref, vdef, walker, data, |
1674 | visited ? visited : &local_visited, 0); | |
1675 | if (local_visited) | |
1676 | BITMAP_FREE (local_visited); | |
1677 | ||
02c74b9b | 1678 | timevar_pop (TV_ALIAS_STMT_WALK); |
1679 | ||
dd277d48 | 1680 | return ret; |
1681 | } | |
1682 |