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6de9cd9a | 1 | /* Alias analysis for trees. |
c75c517d | 2 | Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010 |
66647d44 | 3 | Free Software Foundation, Inc. |
6de9cd9a DN |
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 | |
9dcd6f09 | 10 | the Free Software Foundation; either version 3, or (at your option) |
6de9cd9a DN |
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 | |
9dcd6f09 NC |
19 | along with GCC; see the file COPYING3. If not see |
20 | <http://www.gnu.org/licenses/>. */ | |
6de9cd9a DN |
21 | |
22 | #include "config.h" | |
23 | #include "system.h" | |
24 | #include "coretypes.h" | |
25 | #include "tm.h" | |
26 | #include "tree.h" | |
6de9cd9a | 27 | #include "tm_p.h" |
6de9cd9a DN |
28 | #include "basic-block.h" |
29 | #include "timevar.h" | |
6de9cd9a DN |
30 | #include "ggc.h" |
31 | #include "langhooks.h" | |
32 | #include "flags.h" | |
33 | #include "function.h" | |
cf835838 | 34 | #include "tree-pretty-print.h" |
6de9cd9a | 35 | #include "tree-dump.h" |
726a989a | 36 | #include "gimple.h" |
6de9cd9a DN |
37 | #include "tree-flow.h" |
38 | #include "tree-inline.h" | |
6de9cd9a DN |
39 | #include "tree-pass.h" |
40 | #include "convert.h" | |
41 | #include "params.h" | |
ea900239 | 42 | #include "ipa-type-escape.h" |
c75ab022 | 43 | #include "vec.h" |
a3648cfc | 44 | #include "bitmap.h" |
e3df376d | 45 | #include "vecprim.h" |
38635499 | 46 | #include "pointer-set.h" |
603802e7 | 47 | #include "alloc-pool.h" |
5006671f | 48 | #include "tree-ssa-alias.h" |
a3648cfc | 49 | |
5006671f | 50 | /* Broad overview of how alias analysis on gimple works: |
38635499 | 51 | |
5006671f RG |
52 | Statements clobbering or using memory are linked through the |
53 | virtual operand factored use-def chain. The virtual operand | |
54 | is unique per function, its symbol is accessible via gimple_vop (cfun). | |
55 | Virtual operands are used for efficiently walking memory statements | |
56 | in the gimple IL and are useful for things like value-numbering as | |
57 | a generation count for memory references. | |
faf2ecc5 | 58 | |
5006671f RG |
59 | SSA_NAME pointers may have associated points-to information |
60 | accessible via the SSA_NAME_PTR_INFO macro. Flow-insensitive | |
61 | points-to information is (re-)computed by the TODO_rebuild_alias | |
62 | pass manager todo. Points-to information is also used for more | |
63 | precise tracking of call-clobbered and call-used variables and | |
64 | related disambiguations. | |
faf2ecc5 | 65 | |
5006671f RG |
66 | This file contains functions for disambiguating memory references, |
67 | the so called alias-oracle and tools for walking of the gimple IL. | |
faf2ecc5 | 68 | |
5006671f | 69 | The main alias-oracle entry-points are |
faf2ecc5 | 70 | |
5006671f | 71 | bool stmt_may_clobber_ref_p (gimple, tree) |
faf2ecc5 | 72 | |
5006671f RG |
73 | This function queries if a statement may invalidate (parts of) |
74 | the memory designated by the reference tree argument. | |
faf2ecc5 | 75 | |
5006671f | 76 | bool ref_maybe_used_by_stmt_p (gimple, tree) |
faf2ecc5 | 77 | |
5006671f RG |
78 | This function queries if a statement may need (parts of) the |
79 | memory designated by the reference tree argument. | |
faf2ecc5 | 80 | |
5006671f RG |
81 | There are variants of these functions that only handle the call |
82 | part of a statement, call_may_clobber_ref_p and ref_maybe_used_by_call_p. | |
83 | Note that these do not disambiguate against a possible call lhs. | |
faf2ecc5 | 84 | |
5006671f | 85 | bool refs_may_alias_p (tree, tree) |
faf2ecc5 | 86 | |
5006671f | 87 | This function tries to disambiguate two reference trees. |
63894637 | 88 | |
5006671f | 89 | bool ptr_deref_may_alias_global_p (tree) |
faf2ecc5 | 90 | |
5006671f RG |
91 | This function queries if dereferencing a pointer variable may |
92 | alias global memory. | |
faf2ecc5 | 93 | |
5006671f RG |
94 | More low-level disambiguators are available and documented in |
95 | this file. Low-level disambiguators dealing with points-to | |
96 | information are in tree-ssa-structalias.c. */ | |
faf2ecc5 | 97 | |
faf2ecc5 | 98 | |
5006671f RG |
99 | /* Query statistics for the different low-level disambiguators. |
100 | A high-level query may trigger multiple of them. */ | |
faf2ecc5 | 101 | |
5006671f RG |
102 | static struct { |
103 | unsigned HOST_WIDE_INT refs_may_alias_p_may_alias; | |
104 | unsigned HOST_WIDE_INT refs_may_alias_p_no_alias; | |
105 | unsigned HOST_WIDE_INT ref_maybe_used_by_call_p_may_alias; | |
106 | unsigned HOST_WIDE_INT ref_maybe_used_by_call_p_no_alias; | |
107 | unsigned HOST_WIDE_INT call_may_clobber_ref_p_may_alias; | |
108 | unsigned HOST_WIDE_INT call_may_clobber_ref_p_no_alias; | |
109 | } alias_stats; | |
faf2ecc5 | 110 | |
5006671f RG |
111 | void |
112 | dump_alias_stats (FILE *s) | |
113 | { | |
114 | fprintf (s, "\nAlias oracle query stats:\n"); | |
115 | fprintf (s, " refs_may_alias_p: " | |
116 | HOST_WIDE_INT_PRINT_DEC" disambiguations, " | |
117 | HOST_WIDE_INT_PRINT_DEC" queries\n", | |
118 | alias_stats.refs_may_alias_p_no_alias, | |
119 | alias_stats.refs_may_alias_p_no_alias | |
120 | + alias_stats.refs_may_alias_p_may_alias); | |
121 | fprintf (s, " ref_maybe_used_by_call_p: " | |
122 | HOST_WIDE_INT_PRINT_DEC" disambiguations, " | |
123 | HOST_WIDE_INT_PRINT_DEC" queries\n", | |
124 | alias_stats.ref_maybe_used_by_call_p_no_alias, | |
125 | alias_stats.refs_may_alias_p_no_alias | |
126 | + alias_stats.ref_maybe_used_by_call_p_may_alias); | |
127 | fprintf (s, " call_may_clobber_ref_p: " | |
128 | HOST_WIDE_INT_PRINT_DEC" disambiguations, " | |
129 | HOST_WIDE_INT_PRINT_DEC" queries\n", | |
130 | alias_stats.call_may_clobber_ref_p_no_alias, | |
131 | alias_stats.call_may_clobber_ref_p_no_alias | |
132 | + alias_stats.call_may_clobber_ref_p_may_alias); | |
133 | } | |
134 | ||
135 | ||
136 | /* Return true, if dereferencing PTR may alias with a global variable. */ | |
6de9cd9a | 137 | |
5006671f RG |
138 | bool |
139 | ptr_deref_may_alias_global_p (tree ptr) | |
6de9cd9a | 140 | { |
5006671f | 141 | struct ptr_info_def *pi; |
38635499 | 142 | |
5006671f RG |
143 | /* If we end up with a pointer constant here that may point |
144 | to global memory. */ | |
145 | if (TREE_CODE (ptr) != SSA_NAME) | |
146 | return true; | |
6de9cd9a | 147 | |
5006671f | 148 | pi = SSA_NAME_PTR_INFO (ptr); |
6de9cd9a | 149 | |
5006671f RG |
150 | /* If we do not have points-to information for this variable, |
151 | we have to punt. */ | |
152 | if (!pi) | |
153 | return true; | |
6de9cd9a | 154 | |
4d7a65ea | 155 | /* ??? This does not use TBAA to prune globals ptr may not access. */ |
5006671f | 156 | return pt_solution_includes_global (&pi->pt); |
6de9cd9a DN |
157 | } |
158 | ||
4d7a65ea RG |
159 | /* Return true if dereferencing PTR may alias DECL. |
160 | The caller is responsible for applying TBAA to see if PTR | |
161 | may access DECL at all. */ | |
6de9cd9a | 162 | |
5006671f RG |
163 | static bool |
164 | ptr_deref_may_alias_decl_p (tree ptr, tree decl) | |
6de9cd9a | 165 | { |
5006671f | 166 | struct ptr_info_def *pi; |
ea900239 | 167 | |
63838157 RG |
168 | gcc_assert ((TREE_CODE (ptr) == SSA_NAME |
169 | || TREE_CODE (ptr) == ADDR_EXPR | |
170 | || TREE_CODE (ptr) == INTEGER_CST) | |
171 | && (TREE_CODE (decl) == VAR_DECL | |
172 | || TREE_CODE (decl) == PARM_DECL | |
173 | || TREE_CODE (decl) == RESULT_DECL)); | |
fd73537b | 174 | |
5006671f RG |
175 | /* Non-aliased variables can not be pointed to. */ |
176 | if (!may_be_aliased (decl)) | |
177 | return false; | |
fd73537b | 178 | |
779704e7 RG |
179 | /* ADDR_EXPR pointers either just offset another pointer or directly |
180 | specify the pointed-to set. */ | |
181 | if (TREE_CODE (ptr) == ADDR_EXPR) | |
182 | { | |
183 | tree base = get_base_address (TREE_OPERAND (ptr, 0)); | |
184 | if (base | |
185 | && INDIRECT_REF_P (base)) | |
186 | ptr = TREE_OPERAND (base, 0); | |
187 | else if (base | |
188 | && SSA_VAR_P (base)) | |
2ea9dc64 | 189 | return base == decl; |
779704e7 RG |
190 | else if (base |
191 | && CONSTANT_CLASS_P (base)) | |
192 | return false; | |
193 | else | |
194 | return true; | |
195 | } | |
196 | ||
63838157 | 197 | /* We can end up with dereferencing constant pointers. |
779704e7 | 198 | Just bail out in this case. */ |
63838157 | 199 | if (TREE_CODE (ptr) == INTEGER_CST) |
779704e7 RG |
200 | return true; |
201 | ||
5006671f RG |
202 | /* If we do not have useful points-to information for this pointer |
203 | we cannot disambiguate anything else. */ | |
204 | pi = SSA_NAME_PTR_INFO (ptr); | |
205 | if (!pi) | |
fd73537b RG |
206 | return true; |
207 | ||
9b87db3c MM |
208 | /* If the decl can be used as a restrict tag and we have a restrict |
209 | pointer and that pointers points-to set doesn't contain this decl | |
210 | then they can't alias. */ | |
211 | if (DECL_RESTRICTED_P (decl) | |
212 | && TYPE_RESTRICT (TREE_TYPE (ptr)) | |
213 | && pi->pt.vars_contains_restrict) | |
25a6a873 | 214 | return bitmap_bit_p (pi->pt.vars, DECL_PT_UID (decl)); |
9b87db3c | 215 | |
5006671f | 216 | return pt_solution_includes (&pi->pt, decl); |
fd73537b | 217 | } |
6de9cd9a | 218 | |
4d7a65ea RG |
219 | /* Return true if dereferenced PTR1 and PTR2 may alias. |
220 | The caller is responsible for applying TBAA to see if accesses | |
221 | through PTR1 and PTR2 may conflict at all. */ | |
6de9cd9a | 222 | |
5006671f RG |
223 | static bool |
224 | ptr_derefs_may_alias_p (tree ptr1, tree ptr2) | |
6de9cd9a | 225 | { |
5006671f | 226 | struct ptr_info_def *pi1, *pi2; |
6de9cd9a | 227 | |
63838157 RG |
228 | gcc_assert ((TREE_CODE (ptr1) == SSA_NAME |
229 | || TREE_CODE (ptr1) == ADDR_EXPR | |
230 | || TREE_CODE (ptr1) == INTEGER_CST) | |
231 | && (TREE_CODE (ptr2) == SSA_NAME | |
232 | || TREE_CODE (ptr2) == ADDR_EXPR | |
233 | || TREE_CODE (ptr2) == INTEGER_CST)); | |
234 | ||
779704e7 RG |
235 | /* ADDR_EXPR pointers either just offset another pointer or directly |
236 | specify the pointed-to set. */ | |
237 | if (TREE_CODE (ptr1) == ADDR_EXPR) | |
238 | { | |
239 | tree base = get_base_address (TREE_OPERAND (ptr1, 0)); | |
240 | if (base | |
241 | && INDIRECT_REF_P (base)) | |
242 | ptr1 = TREE_OPERAND (base, 0); | |
243 | else if (base | |
244 | && SSA_VAR_P (base)) | |
245 | return ptr_deref_may_alias_decl_p (ptr2, base); | |
246 | else | |
247 | return true; | |
248 | } | |
249 | if (TREE_CODE (ptr2) == ADDR_EXPR) | |
250 | { | |
251 | tree base = get_base_address (TREE_OPERAND (ptr2, 0)); | |
252 | if (base | |
253 | && INDIRECT_REF_P (base)) | |
254 | ptr2 = TREE_OPERAND (base, 0); | |
255 | else if (base | |
256 | && SSA_VAR_P (base)) | |
257 | return ptr_deref_may_alias_decl_p (ptr1, base); | |
258 | else | |
259 | return true; | |
260 | } | |
261 | ||
63838157 | 262 | /* We can end up with dereferencing constant pointers. |
779704e7 | 263 | Just bail out in this case. */ |
63838157 RG |
264 | if (TREE_CODE (ptr1) == INTEGER_CST |
265 | || TREE_CODE (ptr2) == INTEGER_CST) | |
5006671f | 266 | return true; |
6de9cd9a | 267 | |
5006671f RG |
268 | /* We may end up with two empty points-to solutions for two same pointers. |
269 | In this case we still want to say both pointers alias, so shortcut | |
270 | that here. */ | |
271 | if (ptr1 == ptr2) | |
272 | return true; | |
53b4bf74 | 273 | |
5006671f RG |
274 | /* If we do not have useful points-to information for either pointer |
275 | we cannot disambiguate anything else. */ | |
276 | pi1 = SSA_NAME_PTR_INFO (ptr1); | |
277 | pi2 = SSA_NAME_PTR_INFO (ptr2); | |
278 | if (!pi1 || !pi2) | |
279 | return true; | |
53b4bf74 | 280 | |
74d27244 RG |
281 | /* If both pointers are restrict-qualified try to disambiguate |
282 | with restrict information. */ | |
283 | if (TYPE_RESTRICT (TREE_TYPE (ptr1)) | |
284 | && TYPE_RESTRICT (TREE_TYPE (ptr2)) | |
285 | && !pt_solutions_same_restrict_base (&pi1->pt, &pi2->pt)) | |
286 | return false; | |
287 | ||
4d7a65ea RG |
288 | /* ??? This does not use TBAA to prune decls from the intersection |
289 | that not both pointers may access. */ | |
5006671f | 290 | return pt_solutions_intersect (&pi1->pt, &pi2->pt); |
53b4bf74 DN |
291 | } |
292 | ||
779704e7 RG |
293 | /* Return true if dereferencing PTR may alias *REF. |
294 | The caller is responsible for applying TBAA to see if PTR | |
295 | may access *REF at all. */ | |
296 | ||
297 | static bool | |
298 | ptr_deref_may_alias_ref_p_1 (tree ptr, ao_ref *ref) | |
299 | { | |
300 | tree base = ao_ref_base (ref); | |
301 | ||
302 | if (INDIRECT_REF_P (base)) | |
303 | return ptr_derefs_may_alias_p (ptr, TREE_OPERAND (base, 0)); | |
304 | else if (SSA_VAR_P (base)) | |
305 | return ptr_deref_may_alias_decl_p (ptr, base); | |
306 | ||
307 | return true; | |
308 | } | |
309 | ||
6de9cd9a DN |
310 | |
311 | /* Dump alias information on FILE. */ | |
312 | ||
313 | void | |
314 | dump_alias_info (FILE *file) | |
315 | { | |
316 | size_t i; | |
317 | const char *funcname | |
673fda6b | 318 | = lang_hooks.decl_printable_name (current_function_decl, 2); |
a3648cfc DB |
319 | referenced_var_iterator rvi; |
320 | tree var; | |
6de9cd9a | 321 | |
5006671f | 322 | fprintf (file, "\n\nAlias information for %s\n\n", funcname); |
53b4bf74 DN |
323 | |
324 | fprintf (file, "Aliased symbols\n\n"); | |
b8698a0f | 325 | |
a3648cfc | 326 | FOR_EACH_REFERENCED_VAR (var, rvi) |
53b4bf74 | 327 | { |
53b4bf74 DN |
328 | if (may_be_aliased (var)) |
329 | dump_variable (file, var); | |
330 | } | |
331 | ||
6b8ed145 RG |
332 | fprintf (file, "\nCall clobber information\n"); |
333 | ||
334 | fprintf (file, "\nESCAPED"); | |
335 | dump_points_to_solution (file, &cfun->gimple_df->escaped); | |
6b8ed145 RG |
336 | |
337 | fprintf (file, "\n\nFlow-insensitive points-to information\n\n"); | |
53b4bf74 | 338 | |
53b4bf74 DN |
339 | for (i = 1; i < num_ssa_names; i++) |
340 | { | |
341 | tree ptr = ssa_name (i); | |
d804d490 | 342 | struct ptr_info_def *pi; |
b8698a0f | 343 | |
5006671f RG |
344 | if (ptr == NULL_TREE |
345 | || SSA_NAME_IN_FREE_LIST (ptr)) | |
d804d490 DN |
346 | continue; |
347 | ||
348 | pi = SSA_NAME_PTR_INFO (ptr); | |
5006671f | 349 | if (pi) |
53b4bf74 DN |
350 | dump_points_to_info_for (file, ptr); |
351 | } | |
6de9cd9a | 352 | |
6de9cd9a DN |
353 | fprintf (file, "\n"); |
354 | } | |
355 | ||
356 | ||
357 | /* Dump alias information on stderr. */ | |
358 | ||
24e47c76 | 359 | DEBUG_FUNCTION void |
6de9cd9a DN |
360 | debug_alias_info (void) |
361 | { | |
362 | dump_alias_info (stderr); | |
363 | } | |
364 | ||
365 | ||
313679b0 DN |
366 | /* Return the alias information associated with pointer T. It creates a |
367 | new instance if none existed. */ | |
368 | ||
de66168d | 369 | struct ptr_info_def * |
313679b0 DN |
370 | get_ptr_info (tree t) |
371 | { | |
372 | struct ptr_info_def *pi; | |
373 | ||
1e128c5f | 374 | gcc_assert (POINTER_TYPE_P (TREE_TYPE (t))); |
313679b0 DN |
375 | |
376 | pi = SSA_NAME_PTR_INFO (t); | |
377 | if (pi == NULL) | |
378 | { | |
a9429e29 | 379 | pi = ggc_alloc_cleared_ptr_info_def (); |
5006671f | 380 | pt_solution_reset (&pi->pt); |
313679b0 DN |
381 | SSA_NAME_PTR_INFO (t) = pi; |
382 | } | |
383 | ||
384 | return pi; | |
385 | } | |
386 | ||
6b8ed145 | 387 | /* Dump the points-to set *PT into FILE. */ |
6de9cd9a | 388 | |
d8903b30 | 389 | void |
6b8ed145 | 390 | dump_points_to_solution (FILE *file, struct pt_solution *pt) |
6de9cd9a | 391 | { |
6b8ed145 RG |
392 | if (pt->anything) |
393 | fprintf (file, ", points-to anything"); | |
6de9cd9a | 394 | |
6b8ed145 RG |
395 | if (pt->nonlocal) |
396 | fprintf (file, ", points-to non-local"); | |
6de9cd9a | 397 | |
6b8ed145 RG |
398 | if (pt->escaped) |
399 | fprintf (file, ", points-to escaped"); | |
400 | ||
25a6a873 RG |
401 | if (pt->ipa_escaped) |
402 | fprintf (file, ", points-to unit escaped"); | |
403 | ||
6b8ed145 RG |
404 | if (pt->null) |
405 | fprintf (file, ", points-to NULL"); | |
406 | ||
407 | if (pt->vars) | |
6de9cd9a | 408 | { |
6b8ed145 RG |
409 | fprintf (file, ", points-to vars: "); |
410 | dump_decl_set (file, pt->vars); | |
411 | if (pt->vars_contains_global) | |
412 | fprintf (file, " (includes global vars)"); | |
25a6a873 RG |
413 | if (pt->vars_contains_restrict) |
414 | fprintf (file, " (includes restrict tags)"); | |
6b8ed145 RG |
415 | } |
416 | } | |
6de9cd9a | 417 | |
6b8ed145 | 418 | /* Dump points-to information for SSA_NAME PTR into FILE. */ |
6de9cd9a | 419 | |
6b8ed145 RG |
420 | void |
421 | dump_points_to_info_for (FILE *file, tree ptr) | |
422 | { | |
423 | struct ptr_info_def *pi = SSA_NAME_PTR_INFO (ptr); | |
6de9cd9a | 424 | |
6b8ed145 | 425 | print_generic_expr (file, ptr, dump_flags); |
a1d13fa1 | 426 | |
6b8ed145 RG |
427 | if (pi) |
428 | dump_points_to_solution (file, &pi->pt); | |
429 | else | |
430 | fprintf (file, ", points-to anything"); | |
6de9cd9a DN |
431 | |
432 | fprintf (file, "\n"); | |
433 | } | |
434 | ||
435 | ||
d8903b30 DN |
436 | /* Dump points-to information for VAR into stderr. */ |
437 | ||
24e47c76 | 438 | DEBUG_FUNCTION void |
d8903b30 DN |
439 | debug_points_to_info_for (tree var) |
440 | { | |
441 | dump_points_to_info_for (stderr, var); | |
442 | } | |
443 | ||
b45d2719 RG |
444 | |
445 | /* Initializes the alias-oracle reference representation *R from REF. */ | |
446 | ||
447 | void | |
448 | ao_ref_init (ao_ref *r, tree ref) | |
449 | { | |
450 | r->ref = ref; | |
451 | r->base = NULL_TREE; | |
452 | r->offset = 0; | |
453 | r->size = -1; | |
454 | r->max_size = -1; | |
455 | r->ref_alias_set = -1; | |
456 | r->base_alias_set = -1; | |
457 | } | |
458 | ||
459 | /* Returns the base object of the memory reference *REF. */ | |
460 | ||
461 | tree | |
462 | ao_ref_base (ao_ref *ref) | |
463 | { | |
464 | if (ref->base) | |
465 | return ref->base; | |
466 | ref->base = get_ref_base_and_extent (ref->ref, &ref->offset, &ref->size, | |
467 | &ref->max_size); | |
468 | return ref->base; | |
469 | } | |
470 | ||
471 | /* Returns the base object alias set of the memory reference *REF. */ | |
472 | ||
473 | static alias_set_type ATTRIBUTE_UNUSED | |
474 | ao_ref_base_alias_set (ao_ref *ref) | |
475 | { | |
476 | if (ref->base_alias_set != -1) | |
477 | return ref->base_alias_set; | |
478 | ref->base_alias_set = get_alias_set (ao_ref_base (ref)); | |
479 | return ref->base_alias_set; | |
480 | } | |
481 | ||
482 | /* Returns the reference alias set of the memory reference *REF. */ | |
483 | ||
484 | alias_set_type | |
485 | ao_ref_alias_set (ao_ref *ref) | |
486 | { | |
487 | if (ref->ref_alias_set != -1) | |
488 | return ref->ref_alias_set; | |
489 | ref->ref_alias_set = get_alias_set (ref->ref); | |
490 | return ref->ref_alias_set; | |
491 | } | |
492 | ||
a778c4e7 RG |
493 | /* Init an alias-oracle reference representation from a gimple pointer |
494 | PTR and a gimple size SIZE in bytes. If SIZE is NULL_TREE the the | |
495 | size is assumed to be unknown. The access is assumed to be only | |
496 | to or after of the pointer target, not before it. */ | |
497 | ||
498 | void | |
499 | ao_ref_init_from_ptr_and_size (ao_ref *ref, tree ptr, tree size) | |
500 | { | |
501 | HOST_WIDE_INT t1, t2; | |
502 | ref->ref = NULL_TREE; | |
503 | if (TREE_CODE (ptr) == ADDR_EXPR) | |
504 | ref->base = get_ref_base_and_extent (TREE_OPERAND (ptr, 0), | |
505 | &ref->offset, &t1, &t2); | |
506 | else | |
507 | { | |
508 | ref->base = build1 (INDIRECT_REF, char_type_node, ptr); | |
509 | ref->offset = 0; | |
510 | } | |
511 | if (size | |
512 | && host_integerp (size, 0) | |
513 | && TREE_INT_CST_LOW (size) * 8 / 8 == TREE_INT_CST_LOW (size)) | |
514 | ref->max_size = ref->size = TREE_INT_CST_LOW (size) * 8; | |
515 | else | |
516 | ref->max_size = ref->size = -1; | |
517 | ref->ref_alias_set = 0; | |
518 | ref->base_alias_set = 0; | |
519 | } | |
520 | ||
5006671f RG |
521 | /* Return 1 if TYPE1 and TYPE2 are to be considered equivalent for the |
522 | purpose of TBAA. Return 0 if they are distinct and -1 if we cannot | |
523 | decide. */ | |
d8903b30 | 524 | |
5006671f RG |
525 | static inline int |
526 | same_type_for_tbaa (tree type1, tree type2) | |
527 | { | |
528 | type1 = TYPE_MAIN_VARIANT (type1); | |
529 | type2 = TYPE_MAIN_VARIANT (type2); | |
6de9cd9a | 530 | |
5006671f RG |
531 | /* If we would have to do structural comparison bail out. */ |
532 | if (TYPE_STRUCTURAL_EQUALITY_P (type1) | |
533 | || TYPE_STRUCTURAL_EQUALITY_P (type2)) | |
534 | return -1; | |
535 | ||
536 | /* Compare the canonical types. */ | |
537 | if (TYPE_CANONICAL (type1) == TYPE_CANONICAL (type2)) | |
538 | return 1; | |
539 | ||
55eb4dab | 540 | /* ??? Array types are not properly unified in all cases as we have |
5006671f RG |
541 | spurious changes in the index types for example. Removing this |
542 | causes all sorts of problems with the Fortran frontend. */ | |
543 | if (TREE_CODE (type1) == ARRAY_TYPE | |
544 | && TREE_CODE (type2) == ARRAY_TYPE) | |
545 | return -1; | |
546 | ||
2743db69 EB |
547 | /* ??? In Ada, an lvalue of an unconstrained type can be used to access an |
548 | object of one of its constrained subtypes, e.g. when a function with an | |
549 | unconstrained parameter passed by reference is called on an object and | |
550 | inlined. But, even in the case of a fixed size, type and subtypes are | |
551 | not equivalent enough as to share the same TYPE_CANONICAL, since this | |
552 | would mean that conversions between them are useless, whereas they are | |
553 | not (e.g. type and subtypes can have different modes). So, in the end, | |
554 | they are only guaranteed to have the same alias set. */ | |
555 | if (get_alias_set (type1) == get_alias_set (type2)) | |
55eb4dab EB |
556 | return -1; |
557 | ||
5006671f RG |
558 | /* The types are known to be not equal. */ |
559 | return 0; | |
560 | } | |
561 | ||
562 | /* Determine if the two component references REF1 and REF2 which are | |
563 | based on access types TYPE1 and TYPE2 and of which at least one is based | |
630d3fad RG |
564 | on an indirect reference may alias. REF2 is the only one that can |
565 | be a decl in which case REF2_IS_DECL is true. | |
566 | REF1_ALIAS_SET, BASE1_ALIAS_SET, REF2_ALIAS_SET and BASE2_ALIAS_SET | |
567 | are the respective alias sets. */ | |
5006671f RG |
568 | |
569 | static bool | |
72580319 | 570 | aliasing_component_refs_p (tree ref1, tree type1, |
630d3fad RG |
571 | alias_set_type ref1_alias_set, |
572 | alias_set_type base1_alias_set, | |
72580319 EB |
573 | HOST_WIDE_INT offset1, HOST_WIDE_INT max_size1, |
574 | tree ref2, tree type2, | |
630d3fad RG |
575 | alias_set_type ref2_alias_set, |
576 | alias_set_type base2_alias_set, | |
577 | HOST_WIDE_INT offset2, HOST_WIDE_INT max_size2, | |
578 | bool ref2_is_decl) | |
5006671f RG |
579 | { |
580 | /* If one reference is a component references through pointers try to find a | |
581 | common base and apply offset based disambiguation. This handles | |
582 | for example | |
583 | struct A { int i; int j; } *q; | |
584 | struct B { struct A a; int k; } *p; | |
585 | disambiguating q->i and p->a.j. */ | |
586 | tree *refp; | |
587 | int same_p; | |
588 | ||
589 | /* Now search for the type1 in the access path of ref2. This | |
590 | would be a common base for doing offset based disambiguation on. */ | |
71dcd609 | 591 | refp = &ref2; |
5006671f RG |
592 | while (handled_component_p (*refp) |
593 | && same_type_for_tbaa (TREE_TYPE (*refp), type1) == 0) | |
594 | refp = &TREE_OPERAND (*refp, 0); | |
595 | same_p = same_type_for_tbaa (TREE_TYPE (*refp), type1); | |
596 | /* If we couldn't compare types we have to bail out. */ | |
597 | if (same_p == -1) | |
598 | return true; | |
599 | else if (same_p == 1) | |
600 | { | |
601 | HOST_WIDE_INT offadj, sztmp, msztmp; | |
602 | get_ref_base_and_extent (*refp, &offadj, &sztmp, &msztmp); | |
603 | offset2 -= offadj; | |
604 | return ranges_overlap_p (offset1, max_size1, offset2, max_size2); | |
605 | } | |
606 | /* If we didn't find a common base, try the other way around. */ | |
71dcd609 | 607 | refp = &ref1; |
5006671f RG |
608 | while (handled_component_p (*refp) |
609 | && same_type_for_tbaa (TREE_TYPE (*refp), type2) == 0) | |
610 | refp = &TREE_OPERAND (*refp, 0); | |
611 | same_p = same_type_for_tbaa (TREE_TYPE (*refp), type2); | |
612 | /* If we couldn't compare types we have to bail out. */ | |
613 | if (same_p == -1) | |
614 | return true; | |
615 | else if (same_p == 1) | |
616 | { | |
617 | HOST_WIDE_INT offadj, sztmp, msztmp; | |
618 | get_ref_base_and_extent (*refp, &offadj, &sztmp, &msztmp); | |
619 | offset1 -= offadj; | |
620 | return ranges_overlap_p (offset1, max_size1, offset2, max_size2); | |
621 | } | |
630d3fad | 622 | |
55eb4dab | 623 | /* If we have two type access paths B1.path1 and B2.path2 they may |
630d3fad RG |
624 | only alias if either B1 is in B2.path2 or B2 is in B1.path1. |
625 | But we can still have a path that goes B1.path1...B2.path2 with | |
626 | a part that we do not see. So we can only disambiguate now | |
627 | if there is no B2 in the tail of path1 and no B1 on the | |
628 | tail of path2. */ | |
629 | if (base1_alias_set == ref2_alias_set | |
630 | || alias_set_subset_of (base1_alias_set, ref2_alias_set)) | |
631 | return true; | |
632 | /* If this is ptr vs. decl then we know there is no ptr ... decl path. */ | |
633 | if (!ref2_is_decl) | |
634 | return (base2_alias_set == ref1_alias_set | |
635 | || alias_set_subset_of (base2_alias_set, ref1_alias_set)); | |
55eb4dab | 636 | return false; |
5006671f RG |
637 | } |
638 | ||
639 | /* Return true if two memory references based on the variables BASE1 | |
dcbd7063 AP |
640 | and BASE2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and |
641 | [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. */ | |
5006671f RG |
642 | |
643 | static bool | |
644 | decl_refs_may_alias_p (tree base1, | |
645 | HOST_WIDE_INT offset1, HOST_WIDE_INT max_size1, | |
646 | tree base2, | |
647 | HOST_WIDE_INT offset2, HOST_WIDE_INT max_size2) | |
6de9cd9a | 648 | { |
5006671f | 649 | gcc_assert (SSA_VAR_P (base1) && SSA_VAR_P (base2)); |
6de9cd9a | 650 | |
5006671f | 651 | /* If both references are based on different variables, they cannot alias. */ |
2ea9dc64 | 652 | if (base1 != base2) |
5006671f | 653 | return false; |
6de9cd9a | 654 | |
5006671f RG |
655 | /* If both references are based on the same variable, they cannot alias if |
656 | the accesses do not overlap. */ | |
657 | return ranges_overlap_p (offset1, max_size1, offset2, max_size2); | |
658 | } | |
659 | ||
660 | /* Return true if an indirect reference based on *PTR1 constrained | |
dcbd7063 AP |
661 | to [OFFSET1, OFFSET1 + MAX_SIZE1) may alias a variable based on BASE2 |
662 | constrained to [OFFSET2, OFFSET2 + MAX_SIZE2). *PTR1 and BASE2 have | |
5006671f RG |
663 | the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1 |
664 | in which case they are computed on-demand. REF1 and REF2 | |
665 | if non-NULL are the complete memory reference trees. */ | |
666 | ||
667 | static bool | |
668 | indirect_ref_may_alias_decl_p (tree ref1, tree ptr1, | |
669 | HOST_WIDE_INT offset1, HOST_WIDE_INT max_size1, | |
630d3fad | 670 | alias_set_type ref1_alias_set, |
5006671f RG |
671 | alias_set_type base1_alias_set, |
672 | tree ref2, tree base2, | |
673 | HOST_WIDE_INT offset2, HOST_WIDE_INT max_size2, | |
630d3fad | 674 | alias_set_type ref2_alias_set, |
5006671f RG |
675 | alias_set_type base2_alias_set) |
676 | { | |
677 | /* If only one reference is based on a variable, they cannot alias if | |
678 | the pointer access is beyond the extent of the variable access. | |
679 | (the pointer base cannot validly point to an offset less than zero | |
680 | of the variable). | |
681 | They also cannot alias if the pointer may not point to the decl. */ | |
682 | if (max_size2 != -1 | |
683 | && !ranges_overlap_p (offset1, max_size1, 0, offset2 + max_size2)) | |
684 | return false; | |
685 | if (!ptr_deref_may_alias_decl_p (ptr1, base2)) | |
686 | return false; | |
687 | ||
688 | /* Disambiguations that rely on strict aliasing rules follow. */ | |
689 | if (!flag_strict_aliasing) | |
690 | return true; | |
691 | ||
692 | /* If the alias set for a pointer access is zero all bets are off. */ | |
693 | if (base1_alias_set == -1) | |
694 | base1_alias_set = get_deref_alias_set (ptr1); | |
695 | if (base1_alias_set == 0) | |
696 | return true; | |
697 | if (base2_alias_set == -1) | |
698 | base2_alias_set = get_alias_set (base2); | |
699 | ||
700 | /* If both references are through the same type, they do not alias | |
701 | if the accesses do not overlap. This does extra disambiguation | |
702 | for mixed/pointer accesses but requires strict aliasing. */ | |
703 | if (same_type_for_tbaa (TREE_TYPE (TREE_TYPE (ptr1)), | |
704 | TREE_TYPE (base2)) == 1) | |
705 | return ranges_overlap_p (offset1, max_size1, offset2, max_size2); | |
706 | ||
707 | /* The only way to access a variable is through a pointer dereference | |
708 | of the same alias set or a subset of it. */ | |
709 | if (base1_alias_set != base2_alias_set | |
710 | && !alias_set_subset_of (base1_alias_set, base2_alias_set)) | |
711 | return false; | |
712 | ||
713 | /* Do access-path based disambiguation. */ | |
714 | if (ref1 && ref2 | |
715 | && handled_component_p (ref1) | |
716 | && handled_component_p (ref2)) | |
72580319 | 717 | return aliasing_component_refs_p (ref1, TREE_TYPE (TREE_TYPE (ptr1)), |
630d3fad | 718 | ref1_alias_set, base1_alias_set, |
72580319 EB |
719 | offset1, max_size1, |
720 | ref2, TREE_TYPE (base2), | |
630d3fad RG |
721 | ref2_alias_set, base2_alias_set, |
722 | offset2, max_size2, true); | |
5006671f RG |
723 | |
724 | return true; | |
725 | } | |
726 | ||
727 | /* Return true if two indirect references based on *PTR1 | |
dcbd7063 AP |
728 | and *PTR2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and |
729 | [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. *PTR1 and *PTR2 have | |
5006671f RG |
730 | the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1 |
731 | in which case they are computed on-demand. REF1 and REF2 | |
732 | if non-NULL are the complete memory reference trees. */ | |
733 | ||
734 | static bool | |
735 | indirect_refs_may_alias_p (tree ref1, tree ptr1, | |
736 | HOST_WIDE_INT offset1, HOST_WIDE_INT max_size1, | |
630d3fad | 737 | alias_set_type ref1_alias_set, |
5006671f RG |
738 | alias_set_type base1_alias_set, |
739 | tree ref2, tree ptr2, | |
740 | HOST_WIDE_INT offset2, HOST_WIDE_INT max_size2, | |
630d3fad | 741 | alias_set_type ref2_alias_set, |
5006671f RG |
742 | alias_set_type base2_alias_set) |
743 | { | |
744 | /* If both bases are based on pointers they cannot alias if they may not | |
745 | point to the same memory object or if they point to the same object | |
746 | and the accesses do not overlap. */ | |
747 | if (operand_equal_p (ptr1, ptr2, 0)) | |
748 | return ranges_overlap_p (offset1, max_size1, offset2, max_size2); | |
749 | if (!ptr_derefs_may_alias_p (ptr1, ptr2)) | |
750 | return false; | |
751 | ||
752 | /* Disambiguations that rely on strict aliasing rules follow. */ | |
753 | if (!flag_strict_aliasing) | |
754 | return true; | |
755 | ||
756 | /* If the alias set for a pointer access is zero all bets are off. */ | |
757 | if (base1_alias_set == -1) | |
758 | base1_alias_set = get_deref_alias_set (ptr1); | |
759 | if (base1_alias_set == 0) | |
760 | return true; | |
761 | if (base2_alias_set == -1) | |
762 | base2_alias_set = get_deref_alias_set (ptr2); | |
763 | if (base2_alias_set == 0) | |
764 | return true; | |
765 | ||
766 | /* If both references are through the same type, they do not alias | |
767 | if the accesses do not overlap. This does extra disambiguation | |
768 | for mixed/pointer accesses but requires strict aliasing. */ | |
769 | if (same_type_for_tbaa (TREE_TYPE (TREE_TYPE (ptr1)), | |
770 | TREE_TYPE (TREE_TYPE (ptr2))) == 1) | |
771 | return ranges_overlap_p (offset1, max_size1, offset2, max_size2); | |
772 | ||
773 | /* Do type-based disambiguation. */ | |
774 | if (base1_alias_set != base2_alias_set | |
775 | && !alias_sets_conflict_p (base1_alias_set, base2_alias_set)) | |
776 | return false; | |
777 | ||
778 | /* Do access-path based disambiguation. */ | |
779 | if (ref1 && ref2 | |
780 | && handled_component_p (ref1) | |
781 | && handled_component_p (ref2)) | |
72580319 | 782 | return aliasing_component_refs_p (ref1, TREE_TYPE (TREE_TYPE (ptr1)), |
630d3fad | 783 | ref1_alias_set, base1_alias_set, |
72580319 EB |
784 | offset1, max_size1, |
785 | ref2, TREE_TYPE (TREE_TYPE (ptr2)), | |
630d3fad RG |
786 | ref2_alias_set, base2_alias_set, |
787 | offset2, max_size2, false); | |
5006671f RG |
788 | |
789 | return true; | |
790 | } | |
791 | ||
792 | /* Return true, if the two memory references REF1 and REF2 may alias. */ | |
793 | ||
55b34b5f | 794 | bool |
b45d2719 | 795 | refs_may_alias_p_1 (ao_ref *ref1, ao_ref *ref2, bool tbaa_p) |
5006671f RG |
796 | { |
797 | tree base1, base2; | |
798 | HOST_WIDE_INT offset1 = 0, offset2 = 0; | |
5006671f RG |
799 | HOST_WIDE_INT max_size1 = -1, max_size2 = -1; |
800 | bool var1_p, var2_p, ind1_p, ind2_p; | |
4d7a65ea | 801 | alias_set_type set; |
5006671f | 802 | |
b45d2719 RG |
803 | gcc_assert ((!ref1->ref |
804 | || SSA_VAR_P (ref1->ref) | |
805 | || handled_component_p (ref1->ref) | |
806 | || INDIRECT_REF_P (ref1->ref) | |
1307c758 RG |
807 | || TREE_CODE (ref1->ref) == TARGET_MEM_REF |
808 | || TREE_CODE (ref1->ref) == CONST_DECL) | |
b45d2719 RG |
809 | && (!ref2->ref |
810 | || SSA_VAR_P (ref2->ref) | |
811 | || handled_component_p (ref2->ref) | |
812 | || INDIRECT_REF_P (ref2->ref) | |
1307c758 RG |
813 | || TREE_CODE (ref2->ref) == TARGET_MEM_REF |
814 | || TREE_CODE (ref2->ref) == CONST_DECL)); | |
5006671f | 815 | |
5006671f | 816 | /* Decompose the references into their base objects and the access. */ |
b45d2719 RG |
817 | base1 = ao_ref_base (ref1); |
818 | offset1 = ref1->offset; | |
b45d2719 RG |
819 | max_size1 = ref1->max_size; |
820 | base2 = ao_ref_base (ref2); | |
821 | offset2 = ref2->offset; | |
b45d2719 | 822 | max_size2 = ref2->max_size; |
5006671f RG |
823 | |
824 | /* We can end up with registers or constants as bases for example from | |
825 | *D.1663_44 = VIEW_CONVERT_EXPR<struct DB_LSN>(__tmp$B0F64_59); | |
826 | which is seen as a struct copy. */ | |
827 | if (TREE_CODE (base1) == SSA_NAME | |
5006671f | 828 | || TREE_CODE (base2) == SSA_NAME |
1307c758 RG |
829 | || TREE_CODE (base1) == CONST_DECL |
830 | || TREE_CODE (base2) == CONST_DECL | |
dc5e7298 | 831 | || is_gimple_min_invariant (base1) |
63838157 | 832 | || is_gimple_min_invariant (base2)) |
5006671f RG |
833 | return false; |
834 | ||
3c45b96b RG |
835 | /* We can end up refering to code via function decls. As we likely |
836 | do not properly track code aliases conservatively bail out. */ | |
837 | if (TREE_CODE (base1) == FUNCTION_DECL | |
838 | || TREE_CODE (base2) == FUNCTION_DECL) | |
839 | return true; | |
840 | ||
61e20b90 RG |
841 | /* Defer to simple offset based disambiguation if we have |
842 | references based on two decls. Do this before defering to | |
843 | TBAA to handle must-alias cases in conformance with the | |
844 | GCC extension of allowing type-punning through unions. */ | |
5006671f RG |
845 | var1_p = SSA_VAR_P (base1); |
846 | var2_p = SSA_VAR_P (base2); | |
5006671f RG |
847 | if (var1_p && var2_p) |
848 | return decl_refs_may_alias_p (base1, offset1, max_size1, | |
849 | base2, offset2, max_size2); | |
61e20b90 | 850 | |
91753e21 RG |
851 | ind1_p = INDIRECT_REF_P (base1); |
852 | ind2_p = INDIRECT_REF_P (base2); | |
853 | /* Canonicalize the pointer-vs-decl case. */ | |
854 | if (ind1_p && var2_p) | |
855 | { | |
856 | HOST_WIDE_INT tmp1; | |
857 | tree tmp2; | |
858 | ao_ref *tmp3; | |
859 | tmp1 = offset1; offset1 = offset2; offset2 = tmp1; | |
860 | tmp1 = max_size1; max_size1 = max_size2; max_size2 = tmp1; | |
861 | tmp2 = base1; base1 = base2; base2 = tmp2; | |
862 | tmp3 = ref1; ref1 = ref2; ref2 = tmp3; | |
863 | var1_p = true; | |
864 | ind1_p = false; | |
865 | var2_p = false; | |
866 | ind2_p = true; | |
867 | } | |
868 | ||
869 | /* If we are about to disambiguate pointer-vs-decl try harder to | |
870 | see must-aliases and give leeway to some invalid cases. | |
871 | This covers a pretty minimal set of cases only and does not | |
872 | when called from the RTL oracle. It handles cases like | |
873 | ||
874 | int i = 1; | |
875 | return *(float *)&i; | |
876 | ||
877 | and also fixes gfortran.dg/lto/pr40725. */ | |
878 | if (var1_p && ind2_p | |
879 | && cfun | |
880 | && gimple_in_ssa_p (cfun) | |
881 | && TREE_CODE (TREE_OPERAND (base2, 0)) == SSA_NAME) | |
882 | { | |
883 | gimple def_stmt = SSA_NAME_DEF_STMT (TREE_OPERAND (base2, 0)); | |
884 | while (is_gimple_assign (def_stmt) | |
885 | && (gimple_assign_rhs_code (def_stmt) == SSA_NAME | |
886 | || CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt)))) | |
887 | { | |
888 | tree rhs = gimple_assign_rhs1 (def_stmt); | |
889 | HOST_WIDE_INT offset, size, max_size; | |
890 | ||
891 | /* Look through SSA name copies and pointer conversions. */ | |
892 | if (TREE_CODE (rhs) == SSA_NAME | |
893 | && POINTER_TYPE_P (TREE_TYPE (rhs))) | |
894 | { | |
895 | def_stmt = SSA_NAME_DEF_STMT (rhs); | |
896 | continue; | |
897 | } | |
898 | if (TREE_CODE (rhs) != ADDR_EXPR) | |
899 | break; | |
900 | ||
901 | /* If the pointer is defined as an address based on a decl | |
902 | use plain offset disambiguation and ignore TBAA. */ | |
903 | rhs = TREE_OPERAND (rhs, 0); | |
904 | rhs = get_ref_base_and_extent (rhs, &offset, &size, &max_size); | |
905 | if (SSA_VAR_P (rhs)) | |
906 | { | |
907 | base2 = rhs; | |
908 | offset2 += offset; | |
909 | if (size != max_size | |
910 | || max_size == -1) | |
911 | max_size2 = -1; | |
912 | return decl_refs_may_alias_p (base1, offset1, max_size1, | |
913 | base2, offset2, max_size2); | |
914 | } | |
915 | ||
916 | /* Do not continue looking through &p->x to limit time | |
917 | complexity. */ | |
918 | break; | |
919 | } | |
920 | } | |
921 | ||
61e20b90 | 922 | /* First defer to TBAA if possible. */ |
4d7a65ea RG |
923 | if (tbaa_p |
924 | && flag_strict_aliasing | |
b45d2719 RG |
925 | && !alias_sets_conflict_p (ao_ref_alias_set (ref1), |
926 | ao_ref_alias_set (ref2))) | |
61e20b90 RG |
927 | return false; |
928 | ||
929 | /* If one reference is a TARGET_MEM_REF weird things are allowed. Still | |
930 | TBAA disambiguation based on the access type is possible, so bail | |
931 | out only after that check. */ | |
b45d2719 RG |
932 | if ((ref1->ref && TREE_CODE (ref1->ref) == TARGET_MEM_REF) |
933 | || (ref2->ref && TREE_CODE (ref2->ref) == TARGET_MEM_REF)) | |
61e20b90 RG |
934 | return true; |
935 | ||
936 | /* Dispatch to the pointer-vs-decl or pointer-vs-pointer disambiguators. */ | |
4d7a65ea | 937 | set = tbaa_p ? -1 : 0; |
61e20b90 | 938 | if (var1_p && ind2_p) |
b45d2719 | 939 | return indirect_ref_may_alias_decl_p (ref2->ref, TREE_OPERAND (base2, 0), |
630d3fad RG |
940 | offset2, max_size2, |
941 | ao_ref_alias_set (ref2), set, | |
b45d2719 | 942 | ref1->ref, base1, |
630d3fad RG |
943 | offset1, max_size1, |
944 | ao_ref_alias_set (ref1), set); | |
5006671f | 945 | else if (ind1_p && ind2_p) |
b45d2719 | 946 | return indirect_refs_may_alias_p (ref1->ref, TREE_OPERAND (base1, 0), |
630d3fad RG |
947 | offset1, max_size1, |
948 | ao_ref_alias_set (ref1), set, | |
b45d2719 | 949 | ref2->ref, TREE_OPERAND (base2, 0), |
630d3fad RG |
950 | offset2, max_size2, |
951 | ao_ref_alias_set (ref2), set); | |
5006671f RG |
952 | |
953 | gcc_unreachable (); | |
954 | } | |
955 | ||
956 | bool | |
957 | refs_may_alias_p (tree ref1, tree ref2) | |
958 | { | |
b45d2719 RG |
959 | ao_ref r1, r2; |
960 | bool res; | |
961 | ao_ref_init (&r1, ref1); | |
962 | ao_ref_init (&r2, ref2); | |
963 | res = refs_may_alias_p_1 (&r1, &r2, true); | |
5006671f RG |
964 | if (res) |
965 | ++alias_stats.refs_may_alias_p_may_alias; | |
966 | else | |
967 | ++alias_stats.refs_may_alias_p_no_alias; | |
968 | return res; | |
969 | } | |
970 | ||
4d7a65ea RG |
971 | /* Returns true if there is a anti-dependence for the STORE that |
972 | executes after the LOAD. */ | |
973 | ||
974 | bool | |
975 | refs_anti_dependent_p (tree load, tree store) | |
976 | { | |
b45d2719 RG |
977 | ao_ref r1, r2; |
978 | ao_ref_init (&r1, load); | |
979 | ao_ref_init (&r2, store); | |
980 | return refs_may_alias_p_1 (&r1, &r2, false); | |
4d7a65ea RG |
981 | } |
982 | ||
983 | /* Returns true if there is a output dependence for the stores | |
984 | STORE1 and STORE2. */ | |
985 | ||
986 | bool | |
987 | refs_output_dependent_p (tree store1, tree store2) | |
988 | { | |
b45d2719 RG |
989 | ao_ref r1, r2; |
990 | ao_ref_init (&r1, store1); | |
991 | ao_ref_init (&r2, store2); | |
992 | return refs_may_alias_p_1 (&r1, &r2, false); | |
4d7a65ea | 993 | } |
5006671f RG |
994 | |
995 | /* If the call CALL may use the memory reference REF return true, | |
996 | otherwise return false. */ | |
997 | ||
998 | static bool | |
a778c4e7 | 999 | ref_maybe_used_by_call_p_1 (gimple call, ao_ref *ref) |
5006671f | 1000 | { |
779704e7 | 1001 | tree base, callee; |
5006671f RG |
1002 | unsigned i; |
1003 | int flags = gimple_call_flags (call); | |
1004 | ||
1005 | /* Const functions without a static chain do not implicitly use memory. */ | |
1006 | if (!gimple_call_chain (call) | |
1007 | && (flags & (ECF_CONST|ECF_NOVOPS))) | |
1008 | goto process_args; | |
1009 | ||
a778c4e7 | 1010 | base = ao_ref_base (ref); |
1cb367ae | 1011 | if (!base) |
5006671f RG |
1012 | return true; |
1013 | ||
0609b355 RG |
1014 | /* If the reference is based on a decl that is not aliased the call |
1015 | cannot possibly use it. */ | |
1016 | if (DECL_P (base) | |
1017 | && !may_be_aliased (base) | |
e3ac77ff RG |
1018 | /* But local statics can be used through recursion. */ |
1019 | && !is_global_var (base)) | |
0609b355 RG |
1020 | goto process_args; |
1021 | ||
779704e7 RG |
1022 | callee = gimple_call_fndecl (call); |
1023 | ||
1024 | /* Handle those builtin functions explicitly that do not act as | |
1025 | escape points. See tree-ssa-structalias.c:find_func_aliases | |
1026 | for the list of builtins we might need to handle here. */ | |
1027 | if (callee != NULL_TREE | |
1028 | && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL) | |
1029 | switch (DECL_FUNCTION_CODE (callee)) | |
1030 | { | |
1031 | /* All the following functions clobber memory pointed to by | |
1032 | their first argument. */ | |
1033 | case BUILT_IN_STRCPY: | |
1034 | case BUILT_IN_STRNCPY: | |
779704e7 RG |
1035 | case BUILT_IN_MEMCPY: |
1036 | case BUILT_IN_MEMMOVE: | |
1037 | case BUILT_IN_MEMPCPY: | |
1038 | case BUILT_IN_STPCPY: | |
1039 | case BUILT_IN_STPNCPY: | |
1040 | case BUILT_IN_STRCAT: | |
1041 | case BUILT_IN_STRNCAT: | |
1042 | { | |
a778c4e7 RG |
1043 | ao_ref dref; |
1044 | tree size = NULL_TREE; | |
1045 | if (gimple_call_num_args (call) == 3) | |
1046 | size = gimple_call_arg (call, 2); | |
1047 | ao_ref_init_from_ptr_and_size (&dref, | |
1048 | gimple_call_arg (call, 1), | |
1049 | size); | |
1050 | return refs_may_alias_p_1 (&dref, ref, false); | |
779704e7 | 1051 | } |
1307c758 RG |
1052 | case BUILT_IN_BCOPY: |
1053 | { | |
1054 | ao_ref dref; | |
1055 | tree size = gimple_call_arg (call, 2); | |
1056 | ao_ref_init_from_ptr_and_size (&dref, | |
1057 | gimple_call_arg (call, 0), | |
1058 | size); | |
1059 | return refs_may_alias_p_1 (&dref, ref, false); | |
1060 | } | |
825be69e RG |
1061 | /* The following builtins do not read from memory. */ |
1062 | case BUILT_IN_FREE: | |
c8b3e92f | 1063 | case BUILT_IN_MALLOC: |
e3c70387 | 1064 | case BUILT_IN_CALLOC: |
825be69e RG |
1065 | case BUILT_IN_MEMSET: |
1066 | case BUILT_IN_FREXP: | |
1067 | case BUILT_IN_FREXPF: | |
1068 | case BUILT_IN_FREXPL: | |
1069 | case BUILT_IN_GAMMA_R: | |
1070 | case BUILT_IN_GAMMAF_R: | |
1071 | case BUILT_IN_GAMMAL_R: | |
1072 | case BUILT_IN_LGAMMA_R: | |
1073 | case BUILT_IN_LGAMMAF_R: | |
1074 | case BUILT_IN_LGAMMAL_R: | |
1075 | case BUILT_IN_MODF: | |
1076 | case BUILT_IN_MODFF: | |
1077 | case BUILT_IN_MODFL: | |
1078 | case BUILT_IN_REMQUO: | |
1079 | case BUILT_IN_REMQUOF: | |
1080 | case BUILT_IN_REMQUOL: | |
1081 | case BUILT_IN_SINCOS: | |
1082 | case BUILT_IN_SINCOSF: | |
1083 | case BUILT_IN_SINCOSL: | |
1084 | return false; | |
1085 | ||
779704e7 RG |
1086 | default: |
1087 | /* Fallthru to general call handling. */; | |
1088 | } | |
1089 | ||
5006671f RG |
1090 | /* Check if base is a global static variable that is not read |
1091 | by the function. */ | |
1092 | if (TREE_CODE (base) == VAR_DECL | |
f3380641 | 1093 | && TREE_STATIC (base)) |
6de9cd9a | 1094 | { |
5006671f RG |
1095 | bitmap not_read; |
1096 | ||
1097 | if (callee != NULL_TREE | |
1098 | && (not_read | |
1099 | = ipa_reference_get_not_read_global (cgraph_node (callee))) | |
1100 | && bitmap_bit_p (not_read, DECL_UID (base))) | |
1101 | goto process_args; | |
6de9cd9a DN |
1102 | } |
1103 | ||
d086d311 RG |
1104 | /* Check if the base variable is call-used. */ |
1105 | if (DECL_P (base)) | |
6de9cd9a | 1106 | { |
d086d311 | 1107 | if (pt_solution_includes (gimple_call_use_set (call), base)) |
5006671f RG |
1108 | return true; |
1109 | } | |
d086d311 RG |
1110 | else if (INDIRECT_REF_P (base) |
1111 | && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME) | |
5006671f | 1112 | { |
d086d311 RG |
1113 | struct ptr_info_def *pi = SSA_NAME_PTR_INFO (TREE_OPERAND (base, 0)); |
1114 | if (!pi) | |
1115 | return true; | |
1cb367ae | 1116 | |
d086d311 | 1117 | if (pt_solutions_intersect (gimple_call_use_set (call), &pi->pt)) |
5006671f RG |
1118 | return true; |
1119 | } | |
d086d311 RG |
1120 | else |
1121 | return true; | |
5006671f RG |
1122 | |
1123 | /* Inspect call arguments for passed-by-value aliases. */ | |
1124 | process_args: | |
1125 | for (i = 0; i < gimple_call_num_args (call); ++i) | |
1126 | { | |
1127 | tree op = gimple_call_arg (call, i); | |
0b7b376d RG |
1128 | int flags = gimple_call_arg_flags (call, i); |
1129 | ||
1130 | if (flags & EAF_UNUSED) | |
1131 | continue; | |
5006671f | 1132 | |
5006671f RG |
1133 | if (TREE_CODE (op) == WITH_SIZE_EXPR) |
1134 | op = TREE_OPERAND (op, 0); | |
6de9cd9a | 1135 | |
5006671f | 1136 | if (TREE_CODE (op) != SSA_NAME |
a778c4e7 RG |
1137 | && !is_gimple_min_invariant (op)) |
1138 | { | |
1139 | ao_ref r; | |
1140 | ao_ref_init (&r, op); | |
1141 | if (refs_may_alias_p_1 (&r, ref, true)) | |
1142 | return true; | |
1143 | } | |
6de9cd9a DN |
1144 | } |
1145 | ||
5006671f RG |
1146 | return false; |
1147 | } | |
1148 | ||
1149 | static bool | |
1150 | ref_maybe_used_by_call_p (gimple call, tree ref) | |
1151 | { | |
a778c4e7 RG |
1152 | ao_ref r; |
1153 | bool res; | |
1154 | ao_ref_init (&r, ref); | |
1155 | res = ref_maybe_used_by_call_p_1 (call, &r); | |
5006671f RG |
1156 | if (res) |
1157 | ++alias_stats.ref_maybe_used_by_call_p_may_alias; | |
1158 | else | |
1159 | ++alias_stats.ref_maybe_used_by_call_p_no_alias; | |
1160 | return res; | |
6de9cd9a DN |
1161 | } |
1162 | ||
1163 | ||
5006671f RG |
1164 | /* If the statement STMT may use the memory reference REF return |
1165 | true, otherwise return false. */ | |
6de9cd9a | 1166 | |
5006671f RG |
1167 | bool |
1168 | ref_maybe_used_by_stmt_p (gimple stmt, tree ref) | |
6de9cd9a | 1169 | { |
5006671f RG |
1170 | if (is_gimple_assign (stmt)) |
1171 | { | |
1172 | tree rhs; | |
1173 | ||
1174 | /* All memory assign statements are single. */ | |
1175 | if (!gimple_assign_single_p (stmt)) | |
1176 | return false; | |
1177 | ||
1178 | rhs = gimple_assign_rhs1 (stmt); | |
1179 | if (is_gimple_reg (rhs) | |
1180 | || is_gimple_min_invariant (rhs) | |
1181 | || gimple_assign_rhs_code (stmt) == CONSTRUCTOR) | |
1182 | return false; | |
1183 | ||
1184 | return refs_may_alias_p (rhs, ref); | |
1185 | } | |
1186 | else if (is_gimple_call (stmt)) | |
1187 | return ref_maybe_used_by_call_p (stmt, ref); | |
1188 | ||
1189 | return true; | |
6de9cd9a DN |
1190 | } |
1191 | ||
5006671f RG |
1192 | /* If the call in statement CALL may clobber the memory reference REF |
1193 | return true, otherwise return false. */ | |
6de9cd9a | 1194 | |
5006671f | 1195 | static bool |
b45d2719 | 1196 | call_may_clobber_ref_p_1 (gimple call, ao_ref *ref) |
6de9cd9a | 1197 | { |
e3ac77ff | 1198 | tree base; |
779704e7 | 1199 | tree callee; |
5006671f RG |
1200 | |
1201 | /* If the call is pure or const it cannot clobber anything. */ | |
1202 | if (gimple_call_flags (call) | |
1203 | & (ECF_PURE|ECF_CONST|ECF_LOOPING_CONST_OR_PURE|ECF_NOVOPS)) | |
1204 | return false; | |
1205 | ||
b45d2719 | 1206 | base = ao_ref_base (ref); |
5006671f RG |
1207 | if (!base) |
1208 | return true; | |
1209 | ||
1210 | if (TREE_CODE (base) == SSA_NAME | |
1211 | || CONSTANT_CLASS_P (base)) | |
1212 | return false; | |
1213 | ||
0609b355 RG |
1214 | /* If the reference is based on a decl that is not aliased the call |
1215 | cannot possibly clobber it. */ | |
1216 | if (DECL_P (base) | |
1217 | && !may_be_aliased (base) | |
e3ac77ff RG |
1218 | /* But local non-readonly statics can be modified through recursion |
1219 | or the call may implement a threading barrier which we must | |
1220 | treat as may-def. */ | |
0609b355 | 1221 | && (TREE_READONLY (base) |
e3ac77ff | 1222 | || !is_global_var (base))) |
0609b355 RG |
1223 | return false; |
1224 | ||
779704e7 RG |
1225 | callee = gimple_call_fndecl (call); |
1226 | ||
1227 | /* Handle those builtin functions explicitly that do not act as | |
1228 | escape points. See tree-ssa-structalias.c:find_func_aliases | |
1229 | for the list of builtins we might need to handle here. */ | |
1230 | if (callee != NULL_TREE | |
1231 | && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL) | |
1232 | switch (DECL_FUNCTION_CODE (callee)) | |
1233 | { | |
1234 | /* All the following functions clobber memory pointed to by | |
1235 | their first argument. */ | |
1236 | case BUILT_IN_STRCPY: | |
1237 | case BUILT_IN_STRNCPY: | |
779704e7 RG |
1238 | case BUILT_IN_MEMCPY: |
1239 | case BUILT_IN_MEMMOVE: | |
1240 | case BUILT_IN_MEMPCPY: | |
1241 | case BUILT_IN_STPCPY: | |
1242 | case BUILT_IN_STPNCPY: | |
1243 | case BUILT_IN_STRCAT: | |
1244 | case BUILT_IN_STRNCAT: | |
a778c4e7 | 1245 | case BUILT_IN_MEMSET: |
779704e7 | 1246 | { |
a778c4e7 RG |
1247 | ao_ref dref; |
1248 | tree size = NULL_TREE; | |
1249 | if (gimple_call_num_args (call) == 3) | |
1250 | size = gimple_call_arg (call, 2); | |
1251 | ao_ref_init_from_ptr_and_size (&dref, | |
1252 | gimple_call_arg (call, 0), | |
1253 | size); | |
1254 | return refs_may_alias_p_1 (&dref, ref, false); | |
779704e7 | 1255 | } |
1307c758 RG |
1256 | case BUILT_IN_BCOPY: |
1257 | { | |
1258 | ao_ref dref; | |
1259 | tree size = gimple_call_arg (call, 2); | |
1260 | ao_ref_init_from_ptr_and_size (&dref, | |
1261 | gimple_call_arg (call, 1), | |
1262 | size); | |
1263 | return refs_may_alias_p_1 (&dref, ref, false); | |
1264 | } | |
c8b3e92f RG |
1265 | /* Allocating memory does not have any side-effects apart from |
1266 | being the definition point for the pointer. */ | |
1267 | case BUILT_IN_MALLOC: | |
e3c70387 RG |
1268 | case BUILT_IN_CALLOC: |
1269 | /* Unix98 specifies that errno is set on allocation failure. | |
1270 | Until we properly can track the errno location assume it | |
604d0dbc RG |
1271 | is not a local decl but external or anonymous storage in |
1272 | a different translation unit. Also assume it is of | |
1273 | type int as required by the standard. */ | |
1274 | if (flag_errno_math | |
1275 | && TREE_TYPE (base) == integer_type_node) | |
e3c70387 RG |
1276 | { |
1277 | struct ptr_info_def *pi; | |
604d0dbc RG |
1278 | if (DECL_P (base) |
1279 | && !TREE_STATIC (base)) | |
1280 | return true; | |
1281 | else if (INDIRECT_REF_P (base) | |
1282 | && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME | |
1283 | && (pi = SSA_NAME_PTR_INFO (TREE_OPERAND (base, 0)))) | |
e3c70387 RG |
1284 | return pi->pt.anything || pi->pt.nonlocal; |
1285 | } | |
c8b3e92f | 1286 | return false; |
779704e7 RG |
1287 | /* Freeing memory kills the pointed-to memory. More importantly |
1288 | the call has to serve as a barrier for moving loads and stores | |
a778c4e7 | 1289 | across it. */ |
779704e7 | 1290 | case BUILT_IN_FREE: |
779704e7 RG |
1291 | { |
1292 | tree ptr = gimple_call_arg (call, 0); | |
1293 | return ptr_deref_may_alias_ref_p_1 (ptr, ref); | |
1294 | } | |
779704e7 RG |
1295 | case BUILT_IN_GAMMA_R: |
1296 | case BUILT_IN_GAMMAF_R: | |
1297 | case BUILT_IN_GAMMAL_R: | |
1298 | case BUILT_IN_LGAMMA_R: | |
1299 | case BUILT_IN_LGAMMAF_R: | |
1300 | case BUILT_IN_LGAMMAL_R: | |
825be69e RG |
1301 | { |
1302 | tree out = gimple_call_arg (call, 1); | |
1303 | if (ptr_deref_may_alias_ref_p_1 (out, ref)) | |
1304 | return true; | |
1305 | if (flag_errno_math) | |
1306 | break; | |
1307 | return false; | |
1308 | } | |
1309 | case BUILT_IN_FREXP: | |
1310 | case BUILT_IN_FREXPF: | |
1311 | case BUILT_IN_FREXPL: | |
779704e7 RG |
1312 | case BUILT_IN_MODF: |
1313 | case BUILT_IN_MODFF: | |
1314 | case BUILT_IN_MODFL: | |
1315 | { | |
1316 | tree out = gimple_call_arg (call, 1); | |
1317 | return ptr_deref_may_alias_ref_p_1 (out, ref); | |
1318 | } | |
1319 | case BUILT_IN_REMQUO: | |
1320 | case BUILT_IN_REMQUOF: | |
1321 | case BUILT_IN_REMQUOL: | |
1322 | { | |
1323 | tree out = gimple_call_arg (call, 2); | |
825be69e RG |
1324 | if (ptr_deref_may_alias_ref_p_1 (out, ref)) |
1325 | return true; | |
1326 | if (flag_errno_math) | |
1327 | break; | |
1328 | return false; | |
779704e7 RG |
1329 | } |
1330 | case BUILT_IN_SINCOS: | |
1331 | case BUILT_IN_SINCOSF: | |
1332 | case BUILT_IN_SINCOSL: | |
1333 | { | |
1334 | tree sin = gimple_call_arg (call, 1); | |
1335 | tree cos = gimple_call_arg (call, 2); | |
1336 | return (ptr_deref_may_alias_ref_p_1 (sin, ref) | |
1337 | || ptr_deref_may_alias_ref_p_1 (cos, ref)); | |
1338 | } | |
1339 | default: | |
1340 | /* Fallthru to general call handling. */; | |
1341 | } | |
1342 | ||
5006671f RG |
1343 | /* Check if base is a global static variable that is not written |
1344 | by the function. */ | |
779704e7 RG |
1345 | if (callee != NULL_TREE |
1346 | && TREE_CODE (base) == VAR_DECL | |
f3380641 | 1347 | && TREE_STATIC (base)) |
6de9cd9a | 1348 | { |
5006671f | 1349 | bitmap not_written; |
306219a2 | 1350 | |
779704e7 RG |
1351 | if ((not_written |
1352 | = ipa_reference_get_not_written_global (cgraph_node (callee))) | |
5006671f RG |
1353 | && bitmap_bit_p (not_written, DECL_UID (base))) |
1354 | return false; | |
6de9cd9a | 1355 | } |
6de9cd9a | 1356 | |
d086d311 | 1357 | /* Check if the base variable is call-clobbered. */ |
5006671f | 1358 | if (DECL_P (base)) |
d086d311 | 1359 | return pt_solution_includes (gimple_call_clobber_set (call), base); |
1cb367ae RG |
1360 | else if (INDIRECT_REF_P (base) |
1361 | && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME) | |
1362 | { | |
1363 | struct ptr_info_def *pi = SSA_NAME_PTR_INFO (TREE_OPERAND (base, 0)); | |
1364 | if (!pi) | |
1365 | return true; | |
1366 | ||
d086d311 | 1367 | return pt_solutions_intersect (gimple_call_clobber_set (call), &pi->pt); |
1cb367ae | 1368 | } |
6de9cd9a | 1369 | |
5006671f RG |
1370 | return true; |
1371 | } | |
6de9cd9a | 1372 | |
12de6355 RG |
1373 | /* If the call in statement CALL may clobber the memory reference REF |
1374 | return true, otherwise return false. */ | |
1375 | ||
1376 | bool | |
5006671f | 1377 | call_may_clobber_ref_p (gimple call, tree ref) |
6de9cd9a | 1378 | { |
b45d2719 RG |
1379 | bool res; |
1380 | ao_ref r; | |
1381 | ao_ref_init (&r, ref); | |
1382 | res = call_may_clobber_ref_p_1 (call, &r); | |
5006671f RG |
1383 | if (res) |
1384 | ++alias_stats.call_may_clobber_ref_p_may_alias; | |
1385 | else | |
1386 | ++alias_stats.call_may_clobber_ref_p_no_alias; | |
1387 | return res; | |
6de9cd9a | 1388 | } |
ab8907ef | 1389 | |
5006671f RG |
1390 | |
1391 | /* If the statement STMT may clobber the memory reference REF return true, | |
1392 | otherwise return false. */ | |
ab8907ef RH |
1393 | |
1394 | bool | |
b45d2719 | 1395 | stmt_may_clobber_ref_p_1 (gimple stmt, ao_ref *ref) |
ab8907ef | 1396 | { |
5006671f RG |
1397 | if (is_gimple_call (stmt)) |
1398 | { | |
1399 | tree lhs = gimple_call_lhs (stmt); | |
1400 | if (lhs | |
b45d2719 RG |
1401 | && !is_gimple_reg (lhs)) |
1402 | { | |
1403 | ao_ref r; | |
1404 | ao_ref_init (&r, lhs); | |
1405 | if (refs_may_alias_p_1 (ref, &r, true)) | |
1406 | return true; | |
1407 | } | |
ab8907ef | 1408 | |
b45d2719 | 1409 | return call_may_clobber_ref_p_1 (stmt, ref); |
5006671f RG |
1410 | } |
1411 | else if (is_gimple_assign (stmt)) | |
b45d2719 RG |
1412 | { |
1413 | ao_ref r; | |
1414 | ao_ref_init (&r, gimple_assign_lhs (stmt)); | |
1415 | return refs_may_alias_p_1 (ref, &r, true); | |
1416 | } | |
5006671f | 1417 | else if (gimple_code (stmt) == GIMPLE_ASM) |
ab8907ef RH |
1418 | return true; |
1419 | ||
7e8b322a | 1420 | return false; |
ab8907ef | 1421 | } |
c75ab022 | 1422 | |
b45d2719 RG |
1423 | bool |
1424 | stmt_may_clobber_ref_p (gimple stmt, tree ref) | |
1425 | { | |
1426 | ao_ref r; | |
1427 | ao_ref_init (&r, ref); | |
1428 | return stmt_may_clobber_ref_p_1 (stmt, &r); | |
1429 | } | |
1430 | ||
1431 | ||
5006671f RG |
1432 | /* Walk the virtual use-def chain of VUSE until hitting the virtual operand |
1433 | TARGET or a statement clobbering the memory reference REF in which | |
1434 | case false is returned. The walk starts with VUSE, one argument of PHI. */ | |
1435 | ||
1436 | static bool | |
b45d2719 RG |
1437 | maybe_skip_until (gimple phi, tree target, ao_ref *ref, |
1438 | tree vuse, bitmap *visited) | |
cc0968b0 | 1439 | { |
5006671f RG |
1440 | if (!*visited) |
1441 | *visited = BITMAP_ALLOC (NULL); | |
cc0968b0 | 1442 | |
5006671f RG |
1443 | bitmap_set_bit (*visited, SSA_NAME_VERSION (PHI_RESULT (phi))); |
1444 | ||
1445 | /* Walk until we hit the target. */ | |
1446 | while (vuse != target) | |
cc0968b0 | 1447 | { |
5006671f RG |
1448 | gimple def_stmt = SSA_NAME_DEF_STMT (vuse); |
1449 | /* Recurse for PHI nodes. */ | |
1450 | if (gimple_code (def_stmt) == GIMPLE_PHI) | |
1451 | { | |
1452 | /* An already visited PHI node ends the walk successfully. */ | |
1453 | if (bitmap_bit_p (*visited, SSA_NAME_VERSION (PHI_RESULT (def_stmt)))) | |
1454 | return true; | |
1455 | vuse = get_continuation_for_phi (def_stmt, ref, visited); | |
1456 | if (!vuse) | |
1457 | return false; | |
1458 | continue; | |
1459 | } | |
1460 | /* A clobbering statement or the end of the IL ends it failing. */ | |
1461 | else if (gimple_nop_p (def_stmt) | |
b45d2719 | 1462 | || stmt_may_clobber_ref_p_1 (def_stmt, ref)) |
5006671f RG |
1463 | return false; |
1464 | vuse = gimple_vuse (def_stmt); | |
cc0968b0 | 1465 | } |
5006671f RG |
1466 | return true; |
1467 | } | |
cc0968b0 | 1468 | |
5006671f RG |
1469 | /* Starting from a PHI node for the virtual operand of the memory reference |
1470 | REF find a continuation virtual operand that allows to continue walking | |
1471 | statements dominating PHI skipping only statements that cannot possibly | |
1472 | clobber REF. Returns NULL_TREE if no suitable virtual operand can | |
1473 | be found. */ | |
1474 | ||
84280917 | 1475 | tree |
b45d2719 | 1476 | get_continuation_for_phi (gimple phi, ao_ref *ref, bitmap *visited) |
5006671f RG |
1477 | { |
1478 | unsigned nargs = gimple_phi_num_args (phi); | |
1479 | ||
1480 | /* Through a single-argument PHI we can simply look through. */ | |
1481 | if (nargs == 1) | |
1482 | return PHI_ARG_DEF (phi, 0); | |
1483 | ||
1484 | /* For two arguments try to skip non-aliasing code until we hit | |
1485 | the phi argument definition that dominates the other one. */ | |
1486 | if (nargs == 2) | |
cc0968b0 | 1487 | { |
5006671f RG |
1488 | tree arg0 = PHI_ARG_DEF (phi, 0); |
1489 | tree arg1 = PHI_ARG_DEF (phi, 1); | |
1490 | gimple def0 = SSA_NAME_DEF_STMT (arg0); | |
1491 | gimple def1 = SSA_NAME_DEF_STMT (arg1); | |
84280917 | 1492 | tree common_vuse; |
5006671f RG |
1493 | |
1494 | if (arg0 == arg1) | |
1495 | return arg0; | |
1496 | else if (gimple_nop_p (def0) | |
1497 | || (!gimple_nop_p (def1) | |
1498 | && dominated_by_p (CDI_DOMINATORS, | |
1499 | gimple_bb (def1), gimple_bb (def0)))) | |
1500 | { | |
1501 | if (maybe_skip_until (phi, arg0, ref, arg1, visited)) | |
1502 | return arg0; | |
1503 | } | |
1504 | else if (gimple_nop_p (def1) | |
1505 | || dominated_by_p (CDI_DOMINATORS, | |
1506 | gimple_bb (def0), gimple_bb (def1))) | |
1507 | { | |
1508 | if (maybe_skip_until (phi, arg1, ref, arg0, visited)) | |
1509 | return arg1; | |
1510 | } | |
84280917 MM |
1511 | /* Special case of a diamond: |
1512 | MEM_1 = ... | |
1513 | goto (cond) ? L1 : L2 | |
1514 | L1: store1 = ... #MEM_2 = vuse(MEM_1) | |
1515 | goto L3 | |
1516 | L2: store2 = ... #MEM_3 = vuse(MEM_1) | |
1517 | L3: MEM_4 = PHI<MEM_2, MEM_3> | |
1518 | We were called with the PHI at L3, MEM_2 and MEM_3 don't | |
1519 | dominate each other, but still we can easily skip this PHI node | |
1520 | if we recognize that the vuse MEM operand is the same for both, | |
1521 | and that we can skip both statements (they don't clobber us). | |
1522 | This is still linear. Don't use maybe_skip_until, that might | |
1523 | potentially be slow. */ | |
1524 | else if ((common_vuse = gimple_vuse (def0)) | |
1525 | && common_vuse == gimple_vuse (def1)) | |
1526 | { | |
1527 | if (!stmt_may_clobber_ref_p_1 (def0, ref) | |
1528 | && !stmt_may_clobber_ref_p_1 (def1, ref)) | |
1529 | return common_vuse; | |
1530 | } | |
cc0968b0 | 1531 | } |
5006671f RG |
1532 | |
1533 | return NULL_TREE; | |
cc0968b0 | 1534 | } |
86a07404 | 1535 | |
5006671f RG |
1536 | /* Based on the memory reference REF and its virtual use VUSE call |
1537 | WALKER for each virtual use that is equivalent to VUSE, including VUSE | |
1538 | itself. That is, for each virtual use for which its defining statement | |
1539 | does not clobber REF. | |
51540eba | 1540 | |
5006671f RG |
1541 | WALKER is called with REF, the current virtual use and DATA. If |
1542 | WALKER returns non-NULL the walk stops and its result is returned. | |
1543 | At the end of a non-successful walk NULL is returned. | |
9cf5a7e3 | 1544 | |
01df5c8a RG |
1545 | TRANSLATE if non-NULL is called with a pointer to REF, the virtual |
1546 | use which definition is a statement that may clobber REF and DATA. | |
1547 | If TRANSLATE returns (void *)-1 the walk stops and NULL is returned. | |
1548 | If TRANSLATE returns non-NULL the walk stops and its result is returned. | |
1549 | If TRANSLATE returns NULL the walk continues and TRANSLATE is supposed | |
1550 | to adjust REF and *DATA to make that valid. | |
1551 | ||
5006671f RG |
1552 | TODO: Cache the vector of equivalent vuses per ref, vuse pair. */ |
1553 | ||
1554 | void * | |
b45d2719 RG |
1555 | walk_non_aliased_vuses (ao_ref *ref, tree vuse, |
1556 | void *(*walker)(ao_ref *, tree, void *), | |
1557 | void *(*translate)(ao_ref *, tree, void *), void *data) | |
9cf5a7e3 | 1558 | { |
5006671f RG |
1559 | bitmap visited = NULL; |
1560 | void *res; | |
1561 | ||
8122ccf1 PB |
1562 | timevar_push (TV_ALIAS_STMT_WALK); |
1563 | ||
5006671f RG |
1564 | do |
1565 | { | |
1566 | gimple def_stmt; | |
9cf5a7e3 | 1567 | |
8122ccf1 | 1568 | /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */ |
5006671f RG |
1569 | res = (*walker) (ref, vuse, data); |
1570 | if (res) | |
1571 | break; | |
9cf5a7e3 | 1572 | |
5006671f RG |
1573 | def_stmt = SSA_NAME_DEF_STMT (vuse); |
1574 | if (gimple_nop_p (def_stmt)) | |
1575 | break; | |
1576 | else if (gimple_code (def_stmt) == GIMPLE_PHI) | |
1577 | vuse = get_continuation_for_phi (def_stmt, ref, &visited); | |
1578 | else | |
1579 | { | |
b45d2719 | 1580 | if (stmt_may_clobber_ref_p_1 (def_stmt, ref)) |
01df5c8a RG |
1581 | { |
1582 | if (!translate) | |
1583 | break; | |
b45d2719 | 1584 | res = (*translate) (ref, vuse, data); |
01df5c8a RG |
1585 | /* Failed lookup and translation. */ |
1586 | if (res == (void *)-1) | |
1587 | { | |
1588 | res = NULL; | |
1589 | break; | |
1590 | } | |
1591 | /* Lookup succeeded. */ | |
1592 | else if (res != NULL) | |
1593 | break; | |
1594 | /* Translation succeeded, continue walking. */ | |
1595 | } | |
5006671f RG |
1596 | vuse = gimple_vuse (def_stmt); |
1597 | } | |
1598 | } | |
1599 | while (vuse); | |
cc0968b0 | 1600 | |
5006671f RG |
1601 | if (visited) |
1602 | BITMAP_FREE (visited); | |
cc0968b0 | 1603 | |
8122ccf1 PB |
1604 | timevar_pop (TV_ALIAS_STMT_WALK); |
1605 | ||
5006671f | 1606 | return res; |
9cf5a7e3 KB |
1607 | } |
1608 | ||
fe1f8f44 | 1609 | |
5006671f RG |
1610 | /* Based on the memory reference REF call WALKER for each vdef which |
1611 | defining statement may clobber REF, starting with VDEF. If REF | |
1612 | is NULL_TREE, each defining statement is visited. | |
1613 | ||
1614 | WALKER is called with REF, the current vdef and DATA. If WALKER | |
1615 | returns true the walk is stopped, otherwise it continues. | |
1616 | ||
1617 | At PHI nodes walk_aliased_vdefs forks into one walk for reach | |
1618 | PHI argument (but only one walk continues on merge points), the | |
1619 | return value is true if any of the walks was successful. | |
1620 | ||
1621 | The function returns the number of statements walked. */ | |
fe1f8f44 DB |
1622 | |
1623 | static unsigned int | |
42bc61e0 RG |
1624 | walk_aliased_vdefs_1 (ao_ref *ref, tree vdef, |
1625 | bool (*walker)(ao_ref *, tree, void *), void *data, | |
5006671f | 1626 | bitmap *visited, unsigned int cnt) |
fe1f8f44 | 1627 | { |
5006671f RG |
1628 | do |
1629 | { | |
1630 | gimple def_stmt = SSA_NAME_DEF_STMT (vdef); | |
fe1f8f44 | 1631 | |
5006671f RG |
1632 | if (*visited |
1633 | && !bitmap_set_bit (*visited, SSA_NAME_VERSION (vdef))) | |
1634 | return cnt; | |
1635 | ||
1636 | if (gimple_nop_p (def_stmt)) | |
1637 | return cnt; | |
1638 | else if (gimple_code (def_stmt) == GIMPLE_PHI) | |
1639 | { | |
1640 | unsigned i; | |
1641 | if (!*visited) | |
1642 | *visited = BITMAP_ALLOC (NULL); | |
1643 | for (i = 0; i < gimple_phi_num_args (def_stmt); ++i) | |
1644 | cnt += walk_aliased_vdefs_1 (ref, gimple_phi_arg_def (def_stmt, i), | |
1645 | walker, data, visited, 0); | |
1646 | return cnt; | |
1647 | } | |
1648 | ||
8122ccf1 | 1649 | /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */ |
5006671f RG |
1650 | cnt++; |
1651 | if ((!ref | |
42bc61e0 | 1652 | || stmt_may_clobber_ref_p_1 (def_stmt, ref)) |
5006671f RG |
1653 | && (*walker) (ref, vdef, data)) |
1654 | return cnt; | |
1655 | ||
1656 | vdef = gimple_vuse (def_stmt); | |
1657 | } | |
1658 | while (1); | |
fe1f8f44 DB |
1659 | } |
1660 | ||
5006671f | 1661 | unsigned int |
42bc61e0 RG |
1662 | walk_aliased_vdefs (ao_ref *ref, tree vdef, |
1663 | bool (*walker)(ao_ref *, tree, void *), void *data, | |
5006671f | 1664 | bitmap *visited) |
f9d02384 | 1665 | { |
5006671f RG |
1666 | bitmap local_visited = NULL; |
1667 | unsigned int ret; | |
1668 | ||
8122ccf1 PB |
1669 | timevar_push (TV_ALIAS_STMT_WALK); |
1670 | ||
5006671f RG |
1671 | ret = walk_aliased_vdefs_1 (ref, vdef, walker, data, |
1672 | visited ? visited : &local_visited, 0); | |
1673 | if (local_visited) | |
1674 | BITMAP_FREE (local_visited); | |
1675 | ||
8122ccf1 PB |
1676 | timevar_pop (TV_ALIAS_STMT_WALK); |
1677 | ||
5006671f RG |
1678 | return ret; |
1679 | } | |
1680 |