]>
Commit | Line | Data |
---|---|---|
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" | |
4ee9c684 | 30 | #include "ggc.h" |
31 | #include "langhooks.h" | |
32 | #include "flags.h" | |
7749ee1c | 33 | #include "toplev.h" |
4ee9c684 | 34 | #include "function.h" |
ce084dfc | 35 | #include "tree-pretty-print.h" |
4ee9c684 | 36 | #include "tree-dump.h" |
75a70cf9 | 37 | #include "gimple.h" |
4ee9c684 | 38 | #include "tree-flow.h" |
39 | #include "tree-inline.h" | |
4ee9c684 | 40 | #include "tree-pass.h" |
41 | #include "convert.h" | |
42 | #include "params.h" | |
f7d118a9 | 43 | #include "ipa-type-escape.h" |
2be14d8b | 44 | #include "vec.h" |
a55dc2cd | 45 | #include "bitmap.h" |
05f3df98 | 46 | #include "vecprim.h" |
4fb5e5ca | 47 | #include "pointer-set.h" |
6cc9bd27 | 48 | #include "alloc-pool.h" |
dd277d48 | 49 | #include "tree-ssa-alias.h" |
a55dc2cd | 50 | |
dd277d48 | 51 | /* Broad overview of how alias analysis on gimple works: |
4fb5e5ca | 52 | |
dd277d48 | 53 | Statements clobbering or using memory are linked through the |
54 | virtual operand factored use-def chain. The virtual operand | |
55 | is unique per function, its symbol is accessible via gimple_vop (cfun). | |
56 | Virtual operands are used for efficiently walking memory statements | |
57 | in the gimple IL and are useful for things like value-numbering as | |
58 | a generation count for memory references. | |
339d7079 | 59 | |
dd277d48 | 60 | SSA_NAME pointers may have associated points-to information |
61 | accessible via the SSA_NAME_PTR_INFO macro. Flow-insensitive | |
62 | points-to information is (re-)computed by the TODO_rebuild_alias | |
63 | pass manager todo. Points-to information is also used for more | |
64 | precise tracking of call-clobbered and call-used variables and | |
65 | related disambiguations. | |
339d7079 | 66 | |
dd277d48 | 67 | This file contains functions for disambiguating memory references, |
68 | the so called alias-oracle and tools for walking of the gimple IL. | |
339d7079 | 69 | |
dd277d48 | 70 | The main alias-oracle entry-points are |
339d7079 | 71 | |
dd277d48 | 72 | bool stmt_may_clobber_ref_p (gimple, tree) |
339d7079 | 73 | |
dd277d48 | 74 | This function queries if a statement may invalidate (parts of) |
75 | the memory designated by the reference tree argument. | |
339d7079 | 76 | |
dd277d48 | 77 | bool ref_maybe_used_by_stmt_p (gimple, tree) |
339d7079 | 78 | |
dd277d48 | 79 | This function queries if a statement may need (parts of) the |
80 | memory designated by the reference tree argument. | |
339d7079 | 81 | |
dd277d48 | 82 | There are variants of these functions that only handle the call |
83 | part of a statement, call_may_clobber_ref_p and ref_maybe_used_by_call_p. | |
84 | Note that these do not disambiguate against a possible call lhs. | |
339d7079 | 85 | |
dd277d48 | 86 | bool refs_may_alias_p (tree, tree) |
339d7079 | 87 | |
dd277d48 | 88 | This function tries to disambiguate two reference trees. |
05931b00 | 89 | |
dd277d48 | 90 | bool ptr_deref_may_alias_global_p (tree) |
339d7079 | 91 | |
dd277d48 | 92 | This function queries if dereferencing a pointer variable may |
93 | alias global memory. | |
339d7079 | 94 | |
dd277d48 | 95 | More low-level disambiguators are available and documented in |
96 | this file. Low-level disambiguators dealing with points-to | |
97 | information are in tree-ssa-structalias.c. */ | |
339d7079 | 98 | |
339d7079 | 99 | |
dd277d48 | 100 | /* Query statistics for the different low-level disambiguators. |
101 | A high-level query may trigger multiple of them. */ | |
339d7079 | 102 | |
dd277d48 | 103 | static struct { |
104 | unsigned HOST_WIDE_INT refs_may_alias_p_may_alias; | |
105 | unsigned HOST_WIDE_INT refs_may_alias_p_no_alias; | |
106 | unsigned HOST_WIDE_INT ref_maybe_used_by_call_p_may_alias; | |
107 | unsigned HOST_WIDE_INT ref_maybe_used_by_call_p_no_alias; | |
108 | unsigned HOST_WIDE_INT call_may_clobber_ref_p_may_alias; | |
109 | unsigned HOST_WIDE_INT call_may_clobber_ref_p_no_alias; | |
110 | } alias_stats; | |
339d7079 | 111 | |
dd277d48 | 112 | void |
113 | dump_alias_stats (FILE *s) | |
114 | { | |
115 | fprintf (s, "\nAlias oracle query stats:\n"); | |
116 | fprintf (s, " refs_may_alias_p: " | |
117 | HOST_WIDE_INT_PRINT_DEC" disambiguations, " | |
118 | HOST_WIDE_INT_PRINT_DEC" queries\n", | |
119 | alias_stats.refs_may_alias_p_no_alias, | |
120 | alias_stats.refs_may_alias_p_no_alias | |
121 | + alias_stats.refs_may_alias_p_may_alias); | |
122 | fprintf (s, " ref_maybe_used_by_call_p: " | |
123 | HOST_WIDE_INT_PRINT_DEC" disambiguations, " | |
124 | HOST_WIDE_INT_PRINT_DEC" queries\n", | |
125 | alias_stats.ref_maybe_used_by_call_p_no_alias, | |
126 | alias_stats.refs_may_alias_p_no_alias | |
127 | + alias_stats.ref_maybe_used_by_call_p_may_alias); | |
128 | fprintf (s, " call_may_clobber_ref_p: " | |
129 | HOST_WIDE_INT_PRINT_DEC" disambiguations, " | |
130 | HOST_WIDE_INT_PRINT_DEC" queries\n", | |
131 | alias_stats.call_may_clobber_ref_p_no_alias, | |
132 | alias_stats.call_may_clobber_ref_p_no_alias | |
133 | + alias_stats.call_may_clobber_ref_p_may_alias); | |
134 | } | |
135 | ||
136 | ||
137 | /* Return true, if dereferencing PTR may alias with a global variable. */ | |
4ee9c684 | 138 | |
dd277d48 | 139 | bool |
140 | ptr_deref_may_alias_global_p (tree ptr) | |
4ee9c684 | 141 | { |
dd277d48 | 142 | struct ptr_info_def *pi; |
4fb5e5ca | 143 | |
dd277d48 | 144 | /* If we end up with a pointer constant here that may point |
145 | to global memory. */ | |
146 | if (TREE_CODE (ptr) != SSA_NAME) | |
147 | return true; | |
4ee9c684 | 148 | |
dd277d48 | 149 | pi = SSA_NAME_PTR_INFO (ptr); |
4ee9c684 | 150 | |
dd277d48 | 151 | /* If we do not have points-to information for this variable, |
152 | we have to punt. */ | |
153 | if (!pi) | |
154 | return true; | |
4ee9c684 | 155 | |
2a3ebafa | 156 | /* ??? This does not use TBAA to prune globals ptr may not access. */ |
dd277d48 | 157 | return pt_solution_includes_global (&pi->pt); |
4ee9c684 | 158 | } |
159 | ||
2a3ebafa | 160 | /* Return true if dereferencing PTR may alias DECL. |
161 | The caller is responsible for applying TBAA to see if PTR | |
162 | may access DECL at all. */ | |
4ee9c684 | 163 | |
dd277d48 | 164 | static bool |
165 | ptr_deref_may_alias_decl_p (tree ptr, tree decl) | |
4ee9c684 | 166 | { |
dd277d48 | 167 | struct ptr_info_def *pi; |
f7d118a9 | 168 | |
f85fb819 | 169 | gcc_assert ((TREE_CODE (ptr) == SSA_NAME |
170 | || TREE_CODE (ptr) == ADDR_EXPR | |
171 | || TREE_CODE (ptr) == INTEGER_CST) | |
172 | && (TREE_CODE (decl) == VAR_DECL | |
173 | || TREE_CODE (decl) == PARM_DECL | |
174 | || TREE_CODE (decl) == RESULT_DECL)); | |
2fd0b5dc | 175 | |
dd277d48 | 176 | /* Non-aliased variables can not be pointed to. */ |
177 | if (!may_be_aliased (decl)) | |
178 | return false; | |
2fd0b5dc | 179 | |
047fdd47 | 180 | /* ADDR_EXPR pointers either just offset another pointer or directly |
181 | specify the pointed-to set. */ | |
182 | if (TREE_CODE (ptr) == ADDR_EXPR) | |
183 | { | |
184 | tree base = get_base_address (TREE_OPERAND (ptr, 0)); | |
185 | if (base | |
182cf5a9 | 186 | && (INDIRECT_REF_P (base) |
187 | || TREE_CODE (base) == MEM_REF)) | |
047fdd47 | 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 | |
182cf5a9 | 243 | && (INDIRECT_REF_P (base) |
244 | || TREE_CODE (base) == MEM_REF)) | |
047fdd47 | 245 | ptr1 = TREE_OPERAND (base, 0); |
246 | else if (base | |
247 | && SSA_VAR_P (base)) | |
248 | return ptr_deref_may_alias_decl_p (ptr2, base); | |
249 | else | |
250 | return true; | |
251 | } | |
252 | if (TREE_CODE (ptr2) == ADDR_EXPR) | |
253 | { | |
254 | tree base = get_base_address (TREE_OPERAND (ptr2, 0)); | |
255 | if (base | |
182cf5a9 | 256 | && (INDIRECT_REF_P (base) |
257 | || TREE_CODE (base) == MEM_REF)) | |
047fdd47 | 258 | ptr2 = TREE_OPERAND (base, 0); |
259 | else if (base | |
260 | && SSA_VAR_P (base)) | |
261 | return ptr_deref_may_alias_decl_p (ptr1, base); | |
262 | else | |
263 | return true; | |
264 | } | |
265 | ||
f85fb819 | 266 | /* We can end up with dereferencing constant pointers. |
047fdd47 | 267 | Just bail out in this case. */ |
f85fb819 | 268 | if (TREE_CODE (ptr1) == INTEGER_CST |
269 | || TREE_CODE (ptr2) == INTEGER_CST) | |
dd277d48 | 270 | return true; |
4ee9c684 | 271 | |
dd277d48 | 272 | /* We may end up with two empty points-to solutions for two same pointers. |
273 | In this case we still want to say both pointers alias, so shortcut | |
274 | that here. */ | |
275 | if (ptr1 == ptr2) | |
276 | return true; | |
81d08033 | 277 | |
dd277d48 | 278 | /* If we do not have useful points-to information for either pointer |
279 | we cannot disambiguate anything else. */ | |
280 | pi1 = SSA_NAME_PTR_INFO (ptr1); | |
281 | pi2 = SSA_NAME_PTR_INFO (ptr2); | |
282 | if (!pi1 || !pi2) | |
283 | return true; | |
81d08033 | 284 | |
1c1f1bc0 | 285 | /* If both pointers are restrict-qualified try to disambiguate |
286 | with restrict information. */ | |
287 | if (TYPE_RESTRICT (TREE_TYPE (ptr1)) | |
288 | && TYPE_RESTRICT (TREE_TYPE (ptr2)) | |
289 | && !pt_solutions_same_restrict_base (&pi1->pt, &pi2->pt)) | |
290 | return false; | |
291 | ||
2a3ebafa | 292 | /* ??? This does not use TBAA to prune decls from the intersection |
293 | that not both pointers may access. */ | |
dd277d48 | 294 | return pt_solutions_intersect (&pi1->pt, &pi2->pt); |
81d08033 | 295 | } |
296 | ||
047fdd47 | 297 | /* Return true if dereferencing PTR may alias *REF. |
298 | The caller is responsible for applying TBAA to see if PTR | |
299 | may access *REF at all. */ | |
300 | ||
301 | static bool | |
302 | ptr_deref_may_alias_ref_p_1 (tree ptr, ao_ref *ref) | |
303 | { | |
304 | tree base = ao_ref_base (ref); | |
305 | ||
182cf5a9 | 306 | if (INDIRECT_REF_P (base) |
307 | || TREE_CODE (base) == MEM_REF) | |
047fdd47 | 308 | return ptr_derefs_may_alias_p (ptr, TREE_OPERAND (base, 0)); |
309 | else if (SSA_VAR_P (base)) | |
310 | return ptr_deref_may_alias_decl_p (ptr, base); | |
311 | ||
312 | return true; | |
313 | } | |
314 | ||
4ee9c684 | 315 | |
316 | /* Dump alias information on FILE. */ | |
317 | ||
318 | void | |
319 | dump_alias_info (FILE *file) | |
320 | { | |
321 | size_t i; | |
322 | const char *funcname | |
5135beeb | 323 | = lang_hooks.decl_printable_name (current_function_decl, 2); |
a55dc2cd | 324 | referenced_var_iterator rvi; |
325 | tree var; | |
4ee9c684 | 326 | |
dd277d48 | 327 | fprintf (file, "\n\nAlias information for %s\n\n", funcname); |
81d08033 | 328 | |
329 | fprintf (file, "Aliased symbols\n\n"); | |
48e1416a | 330 | |
a55dc2cd | 331 | FOR_EACH_REFERENCED_VAR (var, rvi) |
81d08033 | 332 | { |
81d08033 | 333 | if (may_be_aliased (var)) |
334 | dump_variable (file, var); | |
335 | } | |
336 | ||
7f81b5ee | 337 | fprintf (file, "\nCall clobber information\n"); |
338 | ||
339 | fprintf (file, "\nESCAPED"); | |
340 | dump_points_to_solution (file, &cfun->gimple_df->escaped); | |
7f81b5ee | 341 | |
342 | fprintf (file, "\n\nFlow-insensitive points-to information\n\n"); | |
81d08033 | 343 | |
81d08033 | 344 | for (i = 1; i < num_ssa_names; i++) |
345 | { | |
346 | tree ptr = ssa_name (i); | |
a48b1470 | 347 | struct ptr_info_def *pi; |
48e1416a | 348 | |
dd277d48 | 349 | if (ptr == NULL_TREE |
350 | || SSA_NAME_IN_FREE_LIST (ptr)) | |
a48b1470 | 351 | continue; |
352 | ||
353 | pi = SSA_NAME_PTR_INFO (ptr); | |
dd277d48 | 354 | if (pi) |
81d08033 | 355 | dump_points_to_info_for (file, ptr); |
356 | } | |
4ee9c684 | 357 | |
4ee9c684 | 358 | fprintf (file, "\n"); |
359 | } | |
360 | ||
361 | ||
362 | /* Dump alias information on stderr. */ | |
363 | ||
4b987fac | 364 | DEBUG_FUNCTION void |
4ee9c684 | 365 | debug_alias_info (void) |
366 | { | |
367 | dump_alias_info (stderr); | |
368 | } | |
369 | ||
370 | ||
786d45db | 371 | /* Return the alias information associated with pointer T. It creates a |
372 | new instance if none existed. */ | |
373 | ||
3276c83b | 374 | struct ptr_info_def * |
786d45db | 375 | get_ptr_info (tree t) |
376 | { | |
377 | struct ptr_info_def *pi; | |
378 | ||
8c0963c4 | 379 | gcc_assert (POINTER_TYPE_P (TREE_TYPE (t))); |
786d45db | 380 | |
381 | pi = SSA_NAME_PTR_INFO (t); | |
382 | if (pi == NULL) | |
383 | { | |
ba72912a | 384 | pi = ggc_alloc_cleared_ptr_info_def (); |
dd277d48 | 385 | pt_solution_reset (&pi->pt); |
786d45db | 386 | SSA_NAME_PTR_INFO (t) = pi; |
387 | } | |
388 | ||
389 | return pi; | |
390 | } | |
391 | ||
7f81b5ee | 392 | /* Dump the points-to set *PT into FILE. */ |
4ee9c684 | 393 | |
d793732c | 394 | void |
7f81b5ee | 395 | dump_points_to_solution (FILE *file, struct pt_solution *pt) |
4ee9c684 | 396 | { |
7f81b5ee | 397 | if (pt->anything) |
398 | fprintf (file, ", points-to anything"); | |
4ee9c684 | 399 | |
7f81b5ee | 400 | if (pt->nonlocal) |
401 | fprintf (file, ", points-to non-local"); | |
4ee9c684 | 402 | |
7f81b5ee | 403 | if (pt->escaped) |
404 | fprintf (file, ", points-to escaped"); | |
405 | ||
1a981e1a | 406 | if (pt->ipa_escaped) |
407 | fprintf (file, ", points-to unit escaped"); | |
408 | ||
7f81b5ee | 409 | if (pt->null) |
410 | fprintf (file, ", points-to NULL"); | |
411 | ||
412 | if (pt->vars) | |
4ee9c684 | 413 | { |
7f81b5ee | 414 | fprintf (file, ", points-to vars: "); |
415 | dump_decl_set (file, pt->vars); | |
416 | if (pt->vars_contains_global) | |
417 | fprintf (file, " (includes global vars)"); | |
1a981e1a | 418 | if (pt->vars_contains_restrict) |
419 | fprintf (file, " (includes restrict tags)"); | |
7f81b5ee | 420 | } |
421 | } | |
4ee9c684 | 422 | |
7f81b5ee | 423 | /* Dump points-to information for SSA_NAME PTR into FILE. */ |
4ee9c684 | 424 | |
7f81b5ee | 425 | void |
426 | dump_points_to_info_for (FILE *file, tree ptr) | |
427 | { | |
428 | struct ptr_info_def *pi = SSA_NAME_PTR_INFO (ptr); | |
4ee9c684 | 429 | |
7f81b5ee | 430 | print_generic_expr (file, ptr, dump_flags); |
1e1a4c8c | 431 | |
7f81b5ee | 432 | if (pi) |
433 | dump_points_to_solution (file, &pi->pt); | |
434 | else | |
435 | fprintf (file, ", points-to anything"); | |
4ee9c684 | 436 | |
437 | fprintf (file, "\n"); | |
438 | } | |
439 | ||
440 | ||
d793732c | 441 | /* Dump points-to information for VAR into stderr. */ |
442 | ||
4b987fac | 443 | DEBUG_FUNCTION void |
d793732c | 444 | debug_points_to_info_for (tree var) |
445 | { | |
446 | dump_points_to_info_for (stderr, var); | |
447 | } | |
448 | ||
3918bd18 | 449 | |
450 | /* Initializes the alias-oracle reference representation *R from REF. */ | |
451 | ||
452 | void | |
453 | ao_ref_init (ao_ref *r, tree ref) | |
454 | { | |
455 | r->ref = ref; | |
456 | r->base = NULL_TREE; | |
457 | r->offset = 0; | |
458 | r->size = -1; | |
459 | r->max_size = -1; | |
460 | r->ref_alias_set = -1; | |
461 | r->base_alias_set = -1; | |
462 | } | |
463 | ||
464 | /* Returns the base object of the memory reference *REF. */ | |
465 | ||
466 | tree | |
467 | ao_ref_base (ao_ref *ref) | |
468 | { | |
469 | if (ref->base) | |
470 | return ref->base; | |
471 | ref->base = get_ref_base_and_extent (ref->ref, &ref->offset, &ref->size, | |
472 | &ref->max_size); | |
473 | return ref->base; | |
474 | } | |
475 | ||
476 | /* Returns the base object alias set of the memory reference *REF. */ | |
477 | ||
182cf5a9 | 478 | static alias_set_type |
3918bd18 | 479 | ao_ref_base_alias_set (ao_ref *ref) |
480 | { | |
182cf5a9 | 481 | tree base_ref; |
3918bd18 | 482 | if (ref->base_alias_set != -1) |
483 | return ref->base_alias_set; | |
182cf5a9 | 484 | if (!ref->ref) |
485 | return 0; | |
486 | base_ref = ref->ref; | |
487 | while (handled_component_p (base_ref)) | |
488 | base_ref = TREE_OPERAND (base_ref, 0); | |
489 | ref->base_alias_set = get_alias_set (base_ref); | |
3918bd18 | 490 | return ref->base_alias_set; |
491 | } | |
492 | ||
493 | /* Returns the reference alias set of the memory reference *REF. */ | |
494 | ||
495 | alias_set_type | |
496 | ao_ref_alias_set (ao_ref *ref) | |
497 | { | |
498 | if (ref->ref_alias_set != -1) | |
499 | return ref->ref_alias_set; | |
500 | ref->ref_alias_set = get_alias_set (ref->ref); | |
501 | return ref->ref_alias_set; | |
502 | } | |
503 | ||
134899ac | 504 | /* Init an alias-oracle reference representation from a gimple pointer |
505 | PTR and a gimple size SIZE in bytes. If SIZE is NULL_TREE the the | |
506 | size is assumed to be unknown. The access is assumed to be only | |
507 | to or after of the pointer target, not before it. */ | |
508 | ||
509 | void | |
510 | ao_ref_init_from_ptr_and_size (ao_ref *ref, tree ptr, tree size) | |
511 | { | |
512 | HOST_WIDE_INT t1, t2; | |
513 | ref->ref = NULL_TREE; | |
514 | if (TREE_CODE (ptr) == ADDR_EXPR) | |
515 | ref->base = get_ref_base_and_extent (TREE_OPERAND (ptr, 0), | |
516 | &ref->offset, &t1, &t2); | |
517 | else | |
518 | { | |
182cf5a9 | 519 | ref->base = build2 (MEM_REF, char_type_node, |
520 | ptr, build_int_cst (ptr_type_node, 0)); | |
134899ac | 521 | ref->offset = 0; |
522 | } | |
523 | if (size | |
524 | && host_integerp (size, 0) | |
525 | && TREE_INT_CST_LOW (size) * 8 / 8 == TREE_INT_CST_LOW (size)) | |
526 | ref->max_size = ref->size = TREE_INT_CST_LOW (size) * 8; | |
527 | else | |
528 | ref->max_size = ref->size = -1; | |
529 | ref->ref_alias_set = 0; | |
530 | ref->base_alias_set = 0; | |
531 | } | |
532 | ||
dd277d48 | 533 | /* Return 1 if TYPE1 and TYPE2 are to be considered equivalent for the |
534 | purpose of TBAA. Return 0 if they are distinct and -1 if we cannot | |
535 | decide. */ | |
d793732c | 536 | |
dd277d48 | 537 | static inline int |
538 | same_type_for_tbaa (tree type1, tree type2) | |
539 | { | |
540 | type1 = TYPE_MAIN_VARIANT (type1); | |
541 | type2 = TYPE_MAIN_VARIANT (type2); | |
4ee9c684 | 542 | |
dd277d48 | 543 | /* If we would have to do structural comparison bail out. */ |
544 | if (TYPE_STRUCTURAL_EQUALITY_P (type1) | |
545 | || TYPE_STRUCTURAL_EQUALITY_P (type2)) | |
546 | return -1; | |
547 | ||
548 | /* Compare the canonical types. */ | |
549 | if (TYPE_CANONICAL (type1) == TYPE_CANONICAL (type2)) | |
550 | return 1; | |
551 | ||
4b4d1513 | 552 | /* ??? Array types are not properly unified in all cases as we have |
dd277d48 | 553 | spurious changes in the index types for example. Removing this |
554 | causes all sorts of problems with the Fortran frontend. */ | |
555 | if (TREE_CODE (type1) == ARRAY_TYPE | |
556 | && TREE_CODE (type2) == ARRAY_TYPE) | |
557 | return -1; | |
558 | ||
102bfc9c | 559 | /* ??? In Ada, an lvalue of an unconstrained type can be used to access an |
560 | object of one of its constrained subtypes, e.g. when a function with an | |
561 | unconstrained parameter passed by reference is called on an object and | |
562 | inlined. But, even in the case of a fixed size, type and subtypes are | |
563 | not equivalent enough as to share the same TYPE_CANONICAL, since this | |
564 | would mean that conversions between them are useless, whereas they are | |
565 | not (e.g. type and subtypes can have different modes). So, in the end, | |
566 | they are only guaranteed to have the same alias set. */ | |
567 | if (get_alias_set (type1) == get_alias_set (type2)) | |
4b4d1513 | 568 | return -1; |
569 | ||
dd277d48 | 570 | /* The types are known to be not equal. */ |
571 | return 0; | |
572 | } | |
573 | ||
574 | /* Determine if the two component references REF1 and REF2 which are | |
575 | based on access types TYPE1 and TYPE2 and of which at least one is based | |
ac30e3b2 | 576 | on an indirect reference may alias. REF2 is the only one that can |
577 | be a decl in which case REF2_IS_DECL is true. | |
578 | REF1_ALIAS_SET, BASE1_ALIAS_SET, REF2_ALIAS_SET and BASE2_ALIAS_SET | |
579 | are the respective alias sets. */ | |
dd277d48 | 580 | |
581 | static bool | |
a42ce2cc | 582 | aliasing_component_refs_p (tree ref1, tree type1, |
ac30e3b2 | 583 | alias_set_type ref1_alias_set, |
584 | alias_set_type base1_alias_set, | |
a42ce2cc | 585 | HOST_WIDE_INT offset1, HOST_WIDE_INT max_size1, |
586 | tree ref2, tree type2, | |
ac30e3b2 | 587 | alias_set_type ref2_alias_set, |
588 | alias_set_type base2_alias_set, | |
589 | HOST_WIDE_INT offset2, HOST_WIDE_INT max_size2, | |
590 | bool ref2_is_decl) | |
dd277d48 | 591 | { |
592 | /* If one reference is a component references through pointers try to find a | |
593 | common base and apply offset based disambiguation. This handles | |
594 | for example | |
595 | struct A { int i; int j; } *q; | |
596 | struct B { struct A a; int k; } *p; | |
597 | disambiguating q->i and p->a.j. */ | |
598 | tree *refp; | |
599 | int same_p; | |
600 | ||
601 | /* Now search for the type1 in the access path of ref2. This | |
602 | would be a common base for doing offset based disambiguation on. */ | |
bc3c318e | 603 | refp = &ref2; |
dd277d48 | 604 | while (handled_component_p (*refp) |
605 | && same_type_for_tbaa (TREE_TYPE (*refp), type1) == 0) | |
606 | refp = &TREE_OPERAND (*refp, 0); | |
607 | same_p = same_type_for_tbaa (TREE_TYPE (*refp), type1); | |
608 | /* If we couldn't compare types we have to bail out. */ | |
609 | if (same_p == -1) | |
610 | return true; | |
611 | else if (same_p == 1) | |
612 | { | |
613 | HOST_WIDE_INT offadj, sztmp, msztmp; | |
614 | get_ref_base_and_extent (*refp, &offadj, &sztmp, &msztmp); | |
615 | offset2 -= offadj; | |
616 | return ranges_overlap_p (offset1, max_size1, offset2, max_size2); | |
617 | } | |
618 | /* If we didn't find a common base, try the other way around. */ | |
bc3c318e | 619 | refp = &ref1; |
dd277d48 | 620 | while (handled_component_p (*refp) |
621 | && same_type_for_tbaa (TREE_TYPE (*refp), type2) == 0) | |
622 | refp = &TREE_OPERAND (*refp, 0); | |
623 | same_p = same_type_for_tbaa (TREE_TYPE (*refp), type2); | |
624 | /* If we couldn't compare types we have to bail out. */ | |
625 | if (same_p == -1) | |
626 | return true; | |
627 | else if (same_p == 1) | |
628 | { | |
629 | HOST_WIDE_INT offadj, sztmp, msztmp; | |
630 | get_ref_base_and_extent (*refp, &offadj, &sztmp, &msztmp); | |
631 | offset1 -= offadj; | |
632 | return ranges_overlap_p (offset1, max_size1, offset2, max_size2); | |
633 | } | |
ac30e3b2 | 634 | |
4b4d1513 | 635 | /* If we have two type access paths B1.path1 and B2.path2 they may |
ac30e3b2 | 636 | only alias if either B1 is in B2.path2 or B2 is in B1.path1. |
637 | But we can still have a path that goes B1.path1...B2.path2 with | |
638 | a part that we do not see. So we can only disambiguate now | |
639 | if there is no B2 in the tail of path1 and no B1 on the | |
640 | tail of path2. */ | |
641 | if (base1_alias_set == ref2_alias_set | |
642 | || alias_set_subset_of (base1_alias_set, ref2_alias_set)) | |
643 | return true; | |
644 | /* If this is ptr vs. decl then we know there is no ptr ... decl path. */ | |
645 | if (!ref2_is_decl) | |
646 | return (base2_alias_set == ref1_alias_set | |
647 | || alias_set_subset_of (base2_alias_set, ref1_alias_set)); | |
4b4d1513 | 648 | return false; |
dd277d48 | 649 | } |
650 | ||
651 | /* Return true if two memory references based on the variables BASE1 | |
077ad5ad | 652 | and BASE2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and |
653 | [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. */ | |
dd277d48 | 654 | |
655 | static bool | |
656 | decl_refs_may_alias_p (tree base1, | |
657 | HOST_WIDE_INT offset1, HOST_WIDE_INT max_size1, | |
658 | tree base2, | |
659 | HOST_WIDE_INT offset2, HOST_WIDE_INT max_size2) | |
4ee9c684 | 660 | { |
dd277d48 | 661 | gcc_assert (SSA_VAR_P (base1) && SSA_VAR_P (base2)); |
4ee9c684 | 662 | |
dd277d48 | 663 | /* If both references are based on different variables, they cannot alias. */ |
7f2d9047 | 664 | if (base1 != base2) |
dd277d48 | 665 | return false; |
4ee9c684 | 666 | |
dd277d48 | 667 | /* If both references are based on the same variable, they cannot alias if |
668 | the accesses do not overlap. */ | |
669 | return ranges_overlap_p (offset1, max_size1, offset2, max_size2); | |
670 | } | |
671 | ||
672 | /* Return true if an indirect reference based on *PTR1 constrained | |
077ad5ad | 673 | to [OFFSET1, OFFSET1 + MAX_SIZE1) may alias a variable based on BASE2 |
674 | constrained to [OFFSET2, OFFSET2 + MAX_SIZE2). *PTR1 and BASE2 have | |
dd277d48 | 675 | the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1 |
676 | in which case they are computed on-demand. REF1 and REF2 | |
677 | if non-NULL are the complete memory reference trees. */ | |
678 | ||
679 | static bool | |
182cf5a9 | 680 | indirect_ref_may_alias_decl_p (tree ref1 ATTRIBUTE_UNUSED, tree base1, |
681 | HOST_WIDE_INT offset1, | |
682 | HOST_WIDE_INT max_size1 ATTRIBUTE_UNUSED, | |
ac30e3b2 | 683 | alias_set_type ref1_alias_set, |
dd277d48 | 684 | alias_set_type base1_alias_set, |
182cf5a9 | 685 | tree ref2 ATTRIBUTE_UNUSED, tree base2, |
dd277d48 | 686 | HOST_WIDE_INT offset2, HOST_WIDE_INT max_size2, |
ac30e3b2 | 687 | alias_set_type ref2_alias_set, |
182cf5a9 | 688 | alias_set_type base2_alias_set, bool tbaa_p) |
dd277d48 | 689 | { |
182cf5a9 | 690 | tree ptr1 = TREE_OPERAND (base1, 0); |
691 | tree ptrtype1; | |
7749ee1c | 692 | HOST_WIDE_INT offset1p = offset1, offset2p = offset2; |
182cf5a9 | 693 | |
7749ee1c | 694 | /* The offset embedded in MEM_REFs can be negative. Bias them |
695 | so that the resulting offset adjustment is positive. */ | |
182cf5a9 | 696 | if (TREE_CODE (base1) == MEM_REF) |
7749ee1c | 697 | { |
698 | double_int moff = mem_ref_offset (base1); | |
699 | moff = double_int_lshift (moff, | |
700 | BITS_PER_UNIT == 8 | |
701 | ? 3 : exact_log2 (BITS_PER_UNIT), | |
702 | HOST_BITS_PER_DOUBLE_INT, true); | |
703 | if (double_int_negative_p (moff)) | |
704 | offset2p += double_int_neg (moff).low; | |
705 | else | |
706 | offset1p += moff.low; | |
707 | } | |
182cf5a9 | 708 | |
dd277d48 | 709 | /* If only one reference is based on a variable, they cannot alias if |
710 | the pointer access is beyond the extent of the variable access. | |
711 | (the pointer base cannot validly point to an offset less than zero | |
712 | of the variable). | |
713 | They also cannot alias if the pointer may not point to the decl. */ | |
7749ee1c | 714 | if (!ranges_overlap_p (MAX (0, offset1p), -1, offset2p, max_size2)) |
dd277d48 | 715 | return false; |
716 | if (!ptr_deref_may_alias_decl_p (ptr1, base2)) | |
717 | return false; | |
718 | ||
719 | /* Disambiguations that rely on strict aliasing rules follow. */ | |
182cf5a9 | 720 | if (!flag_strict_aliasing || !tbaa_p) |
dd277d48 | 721 | return true; |
722 | ||
182cf5a9 | 723 | if (TREE_CODE (base1) == MEM_REF) |
724 | ptrtype1 = TREE_TYPE (TREE_OPERAND (base1, 1)); | |
725 | else | |
726 | ptrtype1 = TREE_TYPE (ptr1); | |
727 | ||
dd277d48 | 728 | /* If the alias set for a pointer access is zero all bets are off. */ |
729 | if (base1_alias_set == -1) | |
182cf5a9 | 730 | base1_alias_set = get_deref_alias_set (ptrtype1); |
dd277d48 | 731 | if (base1_alias_set == 0) |
732 | return true; | |
733 | if (base2_alias_set == -1) | |
734 | base2_alias_set = get_alias_set (base2); | |
735 | ||
736 | /* If both references are through the same type, they do not alias | |
737 | if the accesses do not overlap. This does extra disambiguation | |
182cf5a9 | 738 | for mixed/pointer accesses but requires strict aliasing. |
739 | For MEM_REFs we require that the component-ref offset we computed | |
740 | is relative to the start of the type which we ensure by | |
741 | comparing rvalue and access type and disregarding the constant | |
742 | pointer offset. */ | |
743 | if ((TREE_CODE (base1) != MEM_REF | |
744 | || same_type_for_tbaa (TREE_TYPE (base1), TREE_TYPE (ptrtype1)) == 1) | |
745 | && same_type_for_tbaa (TREE_TYPE (ptrtype1), TREE_TYPE (base2)) == 1) | |
dd277d48 | 746 | return ranges_overlap_p (offset1, max_size1, offset2, max_size2); |
747 | ||
182cf5a9 | 748 | /* When we are trying to disambiguate an access with a pointer dereference |
749 | as base versus one with a decl as base we can use both the size | |
750 | of the decl and its dynamic type for extra disambiguation. | |
751 | ??? We do not know anything about the dynamic type of the decl | |
752 | other than that its alias-set contains base2_alias_set as a subset | |
753 | which does not help us here. */ | |
754 | /* As we know nothing useful about the dynamic type of the decl just | |
755 | use the usual conflict check rather than a subset test. | |
756 | ??? We could introduce -fvery-strict-aliasing when the language | |
757 | does not allow decls to have a dynamic type that differs from their | |
758 | static type. Then we can check | |
759 | !alias_set_subset_of (base1_alias_set, base2_alias_set) instead. */ | |
dd277d48 | 760 | if (base1_alias_set != base2_alias_set |
182cf5a9 | 761 | && !alias_sets_conflict_p (base1_alias_set, base2_alias_set)) |
762 | return false; | |
763 | /* If the size of the access relevant for TBAA through the pointer | |
764 | is bigger than the size of the decl we can't possibly access the | |
765 | decl via that pointer. */ | |
766 | if (DECL_SIZE (base2) && COMPLETE_TYPE_P (TREE_TYPE (ptrtype1)) | |
767 | && TREE_CODE (DECL_SIZE (base2)) == INTEGER_CST | |
768 | && TREE_CODE (TYPE_SIZE (TREE_TYPE (ptrtype1))) == INTEGER_CST | |
769 | /* ??? This in turn may run afoul when a decl of type T which is | |
770 | a member of union type U is accessed through a pointer to | |
771 | type U and sizeof T is smaller than sizeof U. */ | |
772 | && TREE_CODE (TREE_TYPE (ptrtype1)) != UNION_TYPE | |
773 | && TREE_CODE (TREE_TYPE (ptrtype1)) != QUAL_UNION_TYPE | |
774 | && tree_int_cst_lt (DECL_SIZE (base2), TYPE_SIZE (TREE_TYPE (ptrtype1)))) | |
dd277d48 | 775 | return false; |
776 | ||
777 | /* Do access-path based disambiguation. */ | |
778 | if (ref1 && ref2 | |
779 | && handled_component_p (ref1) | |
182cf5a9 | 780 | && handled_component_p (ref2) |
781 | && (TREE_CODE (base1) != MEM_REF | |
782 | || same_type_for_tbaa (TREE_TYPE (base1), TREE_TYPE (ptrtype1)) == 1)) | |
783 | return aliasing_component_refs_p (ref1, TREE_TYPE (ptrtype1), | |
ac30e3b2 | 784 | ref1_alias_set, base1_alias_set, |
a42ce2cc | 785 | offset1, max_size1, |
786 | ref2, TREE_TYPE (base2), | |
ac30e3b2 | 787 | ref2_alias_set, base2_alias_set, |
788 | offset2, max_size2, true); | |
dd277d48 | 789 | |
790 | return true; | |
791 | } | |
792 | ||
793 | /* Return true if two indirect references based on *PTR1 | |
077ad5ad | 794 | and *PTR2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and |
795 | [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. *PTR1 and *PTR2 have | |
dd277d48 | 796 | the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1 |
797 | in which case they are computed on-demand. REF1 and REF2 | |
798 | if non-NULL are the complete memory reference trees. */ | |
799 | ||
800 | static bool | |
182cf5a9 | 801 | indirect_refs_may_alias_p (tree ref1 ATTRIBUTE_UNUSED, tree base1, |
dd277d48 | 802 | HOST_WIDE_INT offset1, HOST_WIDE_INT max_size1, |
ac30e3b2 | 803 | alias_set_type ref1_alias_set, |
dd277d48 | 804 | alias_set_type base1_alias_set, |
182cf5a9 | 805 | tree ref2 ATTRIBUTE_UNUSED, tree base2, |
dd277d48 | 806 | HOST_WIDE_INT offset2, HOST_WIDE_INT max_size2, |
ac30e3b2 | 807 | alias_set_type ref2_alias_set, |
182cf5a9 | 808 | alias_set_type base2_alias_set, bool tbaa_p) |
dd277d48 | 809 | { |
182cf5a9 | 810 | tree ptr1 = TREE_OPERAND (base1, 0); |
811 | tree ptr2 = TREE_OPERAND (base2, 0); | |
812 | tree ptrtype1, ptrtype2; | |
813 | ||
dd277d48 | 814 | /* If both bases are based on pointers they cannot alias if they may not |
815 | point to the same memory object or if they point to the same object | |
816 | and the accesses do not overlap. */ | |
b5c3c805 | 817 | if ((!cfun || gimple_in_ssa_p (cfun)) |
818 | && operand_equal_p (ptr1, ptr2, 0)) | |
182cf5a9 | 819 | { |
7749ee1c | 820 | /* The offset embedded in MEM_REFs can be negative. Bias them |
821 | so that the resulting offset adjustment is positive. */ | |
182cf5a9 | 822 | if (TREE_CODE (base1) == MEM_REF) |
7749ee1c | 823 | { |
824 | double_int moff = mem_ref_offset (base1); | |
825 | moff = double_int_lshift (moff, | |
826 | BITS_PER_UNIT == 8 | |
827 | ? 3 : exact_log2 (BITS_PER_UNIT), | |
828 | HOST_BITS_PER_DOUBLE_INT, true); | |
829 | if (double_int_negative_p (moff)) | |
830 | offset2 += double_int_neg (moff).low; | |
831 | else | |
832 | offset1 += moff.low; | |
833 | } | |
182cf5a9 | 834 | if (TREE_CODE (base2) == MEM_REF) |
7749ee1c | 835 | { |
836 | double_int moff = mem_ref_offset (base2); | |
837 | moff = double_int_lshift (moff, | |
838 | BITS_PER_UNIT == 8 | |
839 | ? 3 : exact_log2 (BITS_PER_UNIT), | |
840 | HOST_BITS_PER_DOUBLE_INT, true); | |
841 | if (double_int_negative_p (moff)) | |
842 | offset1 += double_int_neg (moff).low; | |
843 | else | |
844 | offset2 += moff.low; | |
845 | } | |
182cf5a9 | 846 | return ranges_overlap_p (offset1, max_size1, offset2, max_size2); |
847 | } | |
dd277d48 | 848 | if (!ptr_derefs_may_alias_p (ptr1, ptr2)) |
849 | return false; | |
850 | ||
851 | /* Disambiguations that rely on strict aliasing rules follow. */ | |
182cf5a9 | 852 | if (!flag_strict_aliasing || !tbaa_p) |
dd277d48 | 853 | return true; |
854 | ||
182cf5a9 | 855 | if (TREE_CODE (base1) == MEM_REF) |
856 | ptrtype1 = TREE_TYPE (TREE_OPERAND (base1, 1)); | |
857 | else | |
858 | ptrtype1 = TREE_TYPE (ptr1); | |
859 | if (TREE_CODE (base2) == MEM_REF) | |
860 | ptrtype2 = TREE_TYPE (TREE_OPERAND (base2, 1)); | |
861 | else | |
862 | ptrtype2 = TREE_TYPE (ptr2); | |
863 | ||
dd277d48 | 864 | /* If the alias set for a pointer access is zero all bets are off. */ |
865 | if (base1_alias_set == -1) | |
182cf5a9 | 866 | base1_alias_set = get_deref_alias_set (ptrtype1); |
dd277d48 | 867 | if (base1_alias_set == 0) |
868 | return true; | |
869 | if (base2_alias_set == -1) | |
182cf5a9 | 870 | base2_alias_set = get_deref_alias_set (ptrtype2); |
dd277d48 | 871 | if (base2_alias_set == 0) |
872 | return true; | |
873 | ||
874 | /* If both references are through the same type, they do not alias | |
875 | if the accesses do not overlap. This does extra disambiguation | |
876 | for mixed/pointer accesses but requires strict aliasing. */ | |
182cf5a9 | 877 | if ((TREE_CODE (base1) != MEM_REF |
878 | || same_type_for_tbaa (TREE_TYPE (base1), TREE_TYPE (ptrtype1)) == 1) | |
879 | && (TREE_CODE (base2) != MEM_REF | |
880 | || same_type_for_tbaa (TREE_TYPE (base2), TREE_TYPE (ptrtype2)) == 1) | |
881 | && same_type_for_tbaa (TREE_TYPE (ptrtype1), | |
882 | TREE_TYPE (ptrtype2)) == 1) | |
dd277d48 | 883 | return ranges_overlap_p (offset1, max_size1, offset2, max_size2); |
884 | ||
885 | /* Do type-based disambiguation. */ | |
886 | if (base1_alias_set != base2_alias_set | |
887 | && !alias_sets_conflict_p (base1_alias_set, base2_alias_set)) | |
888 | return false; | |
889 | ||
890 | /* Do access-path based disambiguation. */ | |
891 | if (ref1 && ref2 | |
892 | && handled_component_p (ref1) | |
182cf5a9 | 893 | && handled_component_p (ref2) |
894 | && (TREE_CODE (base1) != MEM_REF | |
895 | || same_type_for_tbaa (TREE_TYPE (base1), TREE_TYPE (ptrtype1)) == 1) | |
896 | && (TREE_CODE (base2) != MEM_REF | |
897 | || same_type_for_tbaa (TREE_TYPE (base2), TREE_TYPE (ptrtype2)) == 1)) | |
898 | return aliasing_component_refs_p (ref1, TREE_TYPE (ptrtype1), | |
ac30e3b2 | 899 | ref1_alias_set, base1_alias_set, |
a42ce2cc | 900 | offset1, max_size1, |
182cf5a9 | 901 | ref2, TREE_TYPE (ptrtype2), |
ac30e3b2 | 902 | ref2_alias_set, base2_alias_set, |
903 | offset2, max_size2, false); | |
dd277d48 | 904 | |
905 | return true; | |
906 | } | |
907 | ||
908 | /* Return true, if the two memory references REF1 and REF2 may alias. */ | |
909 | ||
3a443843 | 910 | bool |
3918bd18 | 911 | refs_may_alias_p_1 (ao_ref *ref1, ao_ref *ref2, bool tbaa_p) |
dd277d48 | 912 | { |
913 | tree base1, base2; | |
914 | HOST_WIDE_INT offset1 = 0, offset2 = 0; | |
dd277d48 | 915 | HOST_WIDE_INT max_size1 = -1, max_size2 = -1; |
916 | bool var1_p, var2_p, ind1_p, ind2_p; | |
917 | ||
c78d5cec | 918 | gcc_checking_assert ((!ref1->ref |
8e7c2b9c | 919 | || TREE_CODE (ref1->ref) == SSA_NAME |
c78d5cec | 920 | || DECL_P (ref1->ref) |
921 | || handled_component_p (ref1->ref) | |
922 | || INDIRECT_REF_P (ref1->ref) | |
182cf5a9 | 923 | || TREE_CODE (ref1->ref) == MEM_REF |
c78d5cec | 924 | || TREE_CODE (ref1->ref) == TARGET_MEM_REF) |
925 | && (!ref2->ref | |
8e7c2b9c | 926 | || TREE_CODE (ref2->ref) == SSA_NAME |
c78d5cec | 927 | || DECL_P (ref2->ref) |
928 | || handled_component_p (ref2->ref) | |
929 | || INDIRECT_REF_P (ref2->ref) | |
182cf5a9 | 930 | || TREE_CODE (ref2->ref) == MEM_REF |
c78d5cec | 931 | || TREE_CODE (ref2->ref) == TARGET_MEM_REF)); |
dd277d48 | 932 | |
dd277d48 | 933 | /* Decompose the references into their base objects and the access. */ |
3918bd18 | 934 | base1 = ao_ref_base (ref1); |
935 | offset1 = ref1->offset; | |
3918bd18 | 936 | max_size1 = ref1->max_size; |
937 | base2 = ao_ref_base (ref2); | |
938 | offset2 = ref2->offset; | |
3918bd18 | 939 | max_size2 = ref2->max_size; |
dd277d48 | 940 | |
941 | /* We can end up with registers or constants as bases for example from | |
942 | *D.1663_44 = VIEW_CONVERT_EXPR<struct DB_LSN>(__tmp$B0F64_59); | |
943 | which is seen as a struct copy. */ | |
944 | if (TREE_CODE (base1) == SSA_NAME | |
dd277d48 | 945 | || TREE_CODE (base2) == SSA_NAME |
119147d1 | 946 | || TREE_CODE (base1) == CONST_DECL |
947 | || TREE_CODE (base2) == CONST_DECL | |
9b973aa6 | 948 | || is_gimple_min_invariant (base1) |
f85fb819 | 949 | || is_gimple_min_invariant (base2)) |
dd277d48 | 950 | return false; |
951 | ||
c78d5cec | 952 | /* We can end up refering to code via function and label decls. |
953 | As we likely do not properly track code aliases conservatively | |
954 | bail out. */ | |
ceefbccc | 955 | if (TREE_CODE (base1) == FUNCTION_DECL |
c78d5cec | 956 | || TREE_CODE (base2) == FUNCTION_DECL |
957 | || TREE_CODE (base1) == LABEL_DECL | |
958 | || TREE_CODE (base2) == LABEL_DECL) | |
ceefbccc | 959 | return true; |
960 | ||
090a8c65 | 961 | /* Defer to simple offset based disambiguation if we have |
962 | references based on two decls. Do this before defering to | |
963 | TBAA to handle must-alias cases in conformance with the | |
964 | GCC extension of allowing type-punning through unions. */ | |
dd277d48 | 965 | var1_p = SSA_VAR_P (base1); |
966 | var2_p = SSA_VAR_P (base2); | |
dd277d48 | 967 | if (var1_p && var2_p) |
968 | return decl_refs_may_alias_p (base1, offset1, max_size1, | |
969 | base2, offset2, max_size2); | |
090a8c65 | 970 | |
182cf5a9 | 971 | ind1_p = INDIRECT_REF_P (base1) || (TREE_CODE (base1) == MEM_REF); |
972 | ind2_p = INDIRECT_REF_P (base2) || (TREE_CODE (base2) == MEM_REF); | |
973 | ||
67817f0f | 974 | /* Canonicalize the pointer-vs-decl case. */ |
975 | if (ind1_p && var2_p) | |
976 | { | |
977 | HOST_WIDE_INT tmp1; | |
978 | tree tmp2; | |
979 | ao_ref *tmp3; | |
980 | tmp1 = offset1; offset1 = offset2; offset2 = tmp1; | |
981 | tmp1 = max_size1; max_size1 = max_size2; max_size2 = tmp1; | |
982 | tmp2 = base1; base1 = base2; base2 = tmp2; | |
983 | tmp3 = ref1; ref1 = ref2; ref2 = tmp3; | |
984 | var1_p = true; | |
985 | ind1_p = false; | |
986 | var2_p = false; | |
987 | ind2_p = true; | |
988 | } | |
989 | ||
090a8c65 | 990 | /* First defer to TBAA if possible. */ |
2a3ebafa | 991 | if (tbaa_p |
992 | && flag_strict_aliasing | |
3918bd18 | 993 | && !alias_sets_conflict_p (ao_ref_alias_set (ref1), |
994 | ao_ref_alias_set (ref2))) | |
090a8c65 | 995 | return false; |
996 | ||
997 | /* If one reference is a TARGET_MEM_REF weird things are allowed. Still | |
998 | TBAA disambiguation based on the access type is possible, so bail | |
999 | out only after that check. */ | |
3918bd18 | 1000 | if ((ref1->ref && TREE_CODE (ref1->ref) == TARGET_MEM_REF) |
1001 | || (ref2->ref && TREE_CODE (ref2->ref) == TARGET_MEM_REF)) | |
090a8c65 | 1002 | return true; |
1003 | ||
1004 | /* Dispatch to the pointer-vs-decl or pointer-vs-pointer disambiguators. */ | |
090a8c65 | 1005 | if (var1_p && ind2_p) |
182cf5a9 | 1006 | return indirect_ref_may_alias_decl_p (ref2->ref, base2, |
ac30e3b2 | 1007 | offset2, max_size2, |
182cf5a9 | 1008 | ao_ref_alias_set (ref2), -1, |
3918bd18 | 1009 | ref1->ref, base1, |
ac30e3b2 | 1010 | offset1, max_size1, |
182cf5a9 | 1011 | ao_ref_alias_set (ref1), |
1012 | ao_ref_base_alias_set (ref1), | |
1013 | tbaa_p); | |
dd277d48 | 1014 | else if (ind1_p && ind2_p) |
182cf5a9 | 1015 | return indirect_refs_may_alias_p (ref1->ref, base1, |
ac30e3b2 | 1016 | offset1, max_size1, |
182cf5a9 | 1017 | ao_ref_alias_set (ref1), -1, |
1018 | ref2->ref, base2, | |
ac30e3b2 | 1019 | offset2, max_size2, |
182cf5a9 | 1020 | ao_ref_alias_set (ref2), -1, |
1021 | tbaa_p); | |
dd277d48 | 1022 | |
1023 | gcc_unreachable (); | |
1024 | } | |
1025 | ||
1026 | bool | |
1027 | refs_may_alias_p (tree ref1, tree ref2) | |
1028 | { | |
3918bd18 | 1029 | ao_ref r1, r2; |
1030 | bool res; | |
1031 | ao_ref_init (&r1, ref1); | |
1032 | ao_ref_init (&r2, ref2); | |
1033 | res = refs_may_alias_p_1 (&r1, &r2, true); | |
dd277d48 | 1034 | if (res) |
1035 | ++alias_stats.refs_may_alias_p_may_alias; | |
1036 | else | |
1037 | ++alias_stats.refs_may_alias_p_no_alias; | |
1038 | return res; | |
1039 | } | |
1040 | ||
2a3ebafa | 1041 | /* Returns true if there is a anti-dependence for the STORE that |
1042 | executes after the LOAD. */ | |
1043 | ||
1044 | bool | |
1045 | refs_anti_dependent_p (tree load, tree store) | |
1046 | { | |
3918bd18 | 1047 | ao_ref r1, r2; |
1048 | ao_ref_init (&r1, load); | |
1049 | ao_ref_init (&r2, store); | |
1050 | return refs_may_alias_p_1 (&r1, &r2, false); | |
2a3ebafa | 1051 | } |
1052 | ||
1053 | /* Returns true if there is a output dependence for the stores | |
1054 | STORE1 and STORE2. */ | |
1055 | ||
1056 | bool | |
1057 | refs_output_dependent_p (tree store1, tree store2) | |
1058 | { | |
3918bd18 | 1059 | ao_ref r1, r2; |
1060 | ao_ref_init (&r1, store1); | |
1061 | ao_ref_init (&r2, store2); | |
1062 | return refs_may_alias_p_1 (&r1, &r2, false); | |
2a3ebafa | 1063 | } |
dd277d48 | 1064 | |
1065 | /* If the call CALL may use the memory reference REF return true, | |
1066 | otherwise return false. */ | |
1067 | ||
1068 | static bool | |
134899ac | 1069 | ref_maybe_used_by_call_p_1 (gimple call, ao_ref *ref) |
dd277d48 | 1070 | { |
047fdd47 | 1071 | tree base, callee; |
dd277d48 | 1072 | unsigned i; |
1073 | int flags = gimple_call_flags (call); | |
1074 | ||
1075 | /* Const functions without a static chain do not implicitly use memory. */ | |
1076 | if (!gimple_call_chain (call) | |
1077 | && (flags & (ECF_CONST|ECF_NOVOPS))) | |
1078 | goto process_args; | |
1079 | ||
134899ac | 1080 | base = ao_ref_base (ref); |
917f08fa | 1081 | if (!base) |
dd277d48 | 1082 | return true; |
1083 | ||
09347e88 | 1084 | /* If the reference is based on a decl that is not aliased the call |
1085 | cannot possibly use it. */ | |
1086 | if (DECL_P (base) | |
1087 | && !may_be_aliased (base) | |
7f7f16d4 | 1088 | /* But local statics can be used through recursion. */ |
1089 | && !is_global_var (base)) | |
09347e88 | 1090 | goto process_args; |
1091 | ||
047fdd47 | 1092 | callee = gimple_call_fndecl (call); |
1093 | ||
1094 | /* Handle those builtin functions explicitly that do not act as | |
1095 | escape points. See tree-ssa-structalias.c:find_func_aliases | |
1096 | for the list of builtins we might need to handle here. */ | |
1097 | if (callee != NULL_TREE | |
1098 | && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL) | |
1099 | switch (DECL_FUNCTION_CODE (callee)) | |
1100 | { | |
1101 | /* All the following functions clobber memory pointed to by | |
1102 | their first argument. */ | |
1103 | case BUILT_IN_STRCPY: | |
1104 | case BUILT_IN_STRNCPY: | |
047fdd47 | 1105 | case BUILT_IN_MEMCPY: |
1106 | case BUILT_IN_MEMMOVE: | |
1107 | case BUILT_IN_MEMPCPY: | |
1108 | case BUILT_IN_STPCPY: | |
1109 | case BUILT_IN_STPNCPY: | |
1110 | case BUILT_IN_STRCAT: | |
1111 | case BUILT_IN_STRNCAT: | |
1112 | { | |
134899ac | 1113 | ao_ref dref; |
1114 | tree size = NULL_TREE; | |
1115 | if (gimple_call_num_args (call) == 3) | |
1116 | size = gimple_call_arg (call, 2); | |
1117 | ao_ref_init_from_ptr_and_size (&dref, | |
1118 | gimple_call_arg (call, 1), | |
1119 | size); | |
1120 | return refs_may_alias_p_1 (&dref, ref, false); | |
047fdd47 | 1121 | } |
119147d1 | 1122 | case BUILT_IN_BCOPY: |
1123 | { | |
1124 | ao_ref dref; | |
1125 | tree size = gimple_call_arg (call, 2); | |
1126 | ao_ref_init_from_ptr_and_size (&dref, | |
1127 | gimple_call_arg (call, 0), | |
1128 | size); | |
1129 | return refs_may_alias_p_1 (&dref, ref, false); | |
1130 | } | |
09d9c774 | 1131 | /* The following builtins do not read from memory. */ |
1132 | case BUILT_IN_FREE: | |
0d3ca08e | 1133 | case BUILT_IN_MALLOC: |
4ef43bbd | 1134 | case BUILT_IN_CALLOC: |
09d9c774 | 1135 | case BUILT_IN_MEMSET: |
1136 | case BUILT_IN_FREXP: | |
1137 | case BUILT_IN_FREXPF: | |
1138 | case BUILT_IN_FREXPL: | |
1139 | case BUILT_IN_GAMMA_R: | |
1140 | case BUILT_IN_GAMMAF_R: | |
1141 | case BUILT_IN_GAMMAL_R: | |
1142 | case BUILT_IN_LGAMMA_R: | |
1143 | case BUILT_IN_LGAMMAF_R: | |
1144 | case BUILT_IN_LGAMMAL_R: | |
1145 | case BUILT_IN_MODF: | |
1146 | case BUILT_IN_MODFF: | |
1147 | case BUILT_IN_MODFL: | |
1148 | case BUILT_IN_REMQUO: | |
1149 | case BUILT_IN_REMQUOF: | |
1150 | case BUILT_IN_REMQUOL: | |
1151 | case BUILT_IN_SINCOS: | |
1152 | case BUILT_IN_SINCOSF: | |
1153 | case BUILT_IN_SINCOSL: | |
1154 | return false; | |
1155 | ||
047fdd47 | 1156 | default: |
1157 | /* Fallthru to general call handling. */; | |
1158 | } | |
1159 | ||
dd277d48 | 1160 | /* Check if base is a global static variable that is not read |
1161 | by the function. */ | |
1162 | if (TREE_CODE (base) == VAR_DECL | |
d97be713 | 1163 | && TREE_STATIC (base)) |
4ee9c684 | 1164 | { |
dd277d48 | 1165 | bitmap not_read; |
1166 | ||
1167 | if (callee != NULL_TREE | |
1168 | && (not_read | |
1169 | = ipa_reference_get_not_read_global (cgraph_node (callee))) | |
1170 | && bitmap_bit_p (not_read, DECL_UID (base))) | |
1171 | goto process_args; | |
4ee9c684 | 1172 | } |
1173 | ||
cb245216 | 1174 | /* Check if the base variable is call-used. */ |
1175 | if (DECL_P (base)) | |
4ee9c684 | 1176 | { |
cb245216 | 1177 | if (pt_solution_includes (gimple_call_use_set (call), base)) |
dd277d48 | 1178 | return true; |
1179 | } | |
182cf5a9 | 1180 | else if ((INDIRECT_REF_P (base) |
1181 | || TREE_CODE (base) == MEM_REF) | |
cb245216 | 1182 | && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME) |
dd277d48 | 1183 | { |
cb245216 | 1184 | struct ptr_info_def *pi = SSA_NAME_PTR_INFO (TREE_OPERAND (base, 0)); |
1185 | if (!pi) | |
1186 | return true; | |
917f08fa | 1187 | |
cb245216 | 1188 | if (pt_solutions_intersect (gimple_call_use_set (call), &pi->pt)) |
dd277d48 | 1189 | return true; |
1190 | } | |
cb245216 | 1191 | else |
1192 | return true; | |
dd277d48 | 1193 | |
1194 | /* Inspect call arguments for passed-by-value aliases. */ | |
1195 | process_args: | |
1196 | for (i = 0; i < gimple_call_num_args (call); ++i) | |
1197 | { | |
1198 | tree op = gimple_call_arg (call, i); | |
8ce86007 | 1199 | int flags = gimple_call_arg_flags (call, i); |
1200 | ||
1201 | if (flags & EAF_UNUSED) | |
1202 | continue; | |
dd277d48 | 1203 | |
dd277d48 | 1204 | if (TREE_CODE (op) == WITH_SIZE_EXPR) |
1205 | op = TREE_OPERAND (op, 0); | |
4ee9c684 | 1206 | |
dd277d48 | 1207 | if (TREE_CODE (op) != SSA_NAME |
134899ac | 1208 | && !is_gimple_min_invariant (op)) |
1209 | { | |
1210 | ao_ref r; | |
1211 | ao_ref_init (&r, op); | |
1212 | if (refs_may_alias_p_1 (&r, ref, true)) | |
1213 | return true; | |
1214 | } | |
4ee9c684 | 1215 | } |
1216 | ||
dd277d48 | 1217 | return false; |
1218 | } | |
1219 | ||
1220 | static bool | |
1221 | ref_maybe_used_by_call_p (gimple call, tree ref) | |
1222 | { | |
134899ac | 1223 | ao_ref r; |
1224 | bool res; | |
1225 | ao_ref_init (&r, ref); | |
1226 | res = ref_maybe_used_by_call_p_1 (call, &r); | |
dd277d48 | 1227 | if (res) |
1228 | ++alias_stats.ref_maybe_used_by_call_p_may_alias; | |
1229 | else | |
1230 | ++alias_stats.ref_maybe_used_by_call_p_no_alias; | |
1231 | return res; | |
4ee9c684 | 1232 | } |
1233 | ||
1234 | ||
dd277d48 | 1235 | /* If the statement STMT may use the memory reference REF return |
1236 | true, otherwise return false. */ | |
4ee9c684 | 1237 | |
dd277d48 | 1238 | bool |
1239 | ref_maybe_used_by_stmt_p (gimple stmt, tree ref) | |
4ee9c684 | 1240 | { |
dd277d48 | 1241 | if (is_gimple_assign (stmt)) |
1242 | { | |
1243 | tree rhs; | |
1244 | ||
1245 | /* All memory assign statements are single. */ | |
1246 | if (!gimple_assign_single_p (stmt)) | |
1247 | return false; | |
1248 | ||
1249 | rhs = gimple_assign_rhs1 (stmt); | |
1250 | if (is_gimple_reg (rhs) | |
1251 | || is_gimple_min_invariant (rhs) | |
1252 | || gimple_assign_rhs_code (stmt) == CONSTRUCTOR) | |
1253 | return false; | |
1254 | ||
1255 | return refs_may_alias_p (rhs, ref); | |
1256 | } | |
1257 | else if (is_gimple_call (stmt)) | |
1258 | return ref_maybe_used_by_call_p (stmt, ref); | |
1259 | ||
1260 | return true; | |
4ee9c684 | 1261 | } |
1262 | ||
dd277d48 | 1263 | /* If the call in statement CALL may clobber the memory reference REF |
1264 | return true, otherwise return false. */ | |
4ee9c684 | 1265 | |
dd277d48 | 1266 | static bool |
3918bd18 | 1267 | call_may_clobber_ref_p_1 (gimple call, ao_ref *ref) |
4ee9c684 | 1268 | { |
7f7f16d4 | 1269 | tree base; |
047fdd47 | 1270 | tree callee; |
dd277d48 | 1271 | |
1272 | /* If the call is pure or const it cannot clobber anything. */ | |
1273 | if (gimple_call_flags (call) | |
1274 | & (ECF_PURE|ECF_CONST|ECF_LOOPING_CONST_OR_PURE|ECF_NOVOPS)) | |
1275 | return false; | |
1276 | ||
3918bd18 | 1277 | base = ao_ref_base (ref); |
dd277d48 | 1278 | if (!base) |
1279 | return true; | |
1280 | ||
1281 | if (TREE_CODE (base) == SSA_NAME | |
1282 | || CONSTANT_CLASS_P (base)) | |
1283 | return false; | |
1284 | ||
09347e88 | 1285 | /* If the reference is based on a decl that is not aliased the call |
1286 | cannot possibly clobber it. */ | |
1287 | if (DECL_P (base) | |
1288 | && !may_be_aliased (base) | |
7f7f16d4 | 1289 | /* But local non-readonly statics can be modified through recursion |
1290 | or the call may implement a threading barrier which we must | |
1291 | treat as may-def. */ | |
09347e88 | 1292 | && (TREE_READONLY (base) |
7f7f16d4 | 1293 | || !is_global_var (base))) |
09347e88 | 1294 | return false; |
1295 | ||
047fdd47 | 1296 | callee = gimple_call_fndecl (call); |
1297 | ||
1298 | /* Handle those builtin functions explicitly that do not act as | |
1299 | escape points. See tree-ssa-structalias.c:find_func_aliases | |
1300 | for the list of builtins we might need to handle here. */ | |
1301 | if (callee != NULL_TREE | |
1302 | && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL) | |
1303 | switch (DECL_FUNCTION_CODE (callee)) | |
1304 | { | |
1305 | /* All the following functions clobber memory pointed to by | |
1306 | their first argument. */ | |
1307 | case BUILT_IN_STRCPY: | |
1308 | case BUILT_IN_STRNCPY: | |
047fdd47 | 1309 | case BUILT_IN_MEMCPY: |
1310 | case BUILT_IN_MEMMOVE: | |
1311 | case BUILT_IN_MEMPCPY: | |
1312 | case BUILT_IN_STPCPY: | |
1313 | case BUILT_IN_STPNCPY: | |
1314 | case BUILT_IN_STRCAT: | |
1315 | case BUILT_IN_STRNCAT: | |
134899ac | 1316 | case BUILT_IN_MEMSET: |
047fdd47 | 1317 | { |
134899ac | 1318 | ao_ref dref; |
1319 | tree size = NULL_TREE; | |
1320 | if (gimple_call_num_args (call) == 3) | |
1321 | size = gimple_call_arg (call, 2); | |
1322 | ao_ref_init_from_ptr_and_size (&dref, | |
1323 | gimple_call_arg (call, 0), | |
1324 | size); | |
1325 | return refs_may_alias_p_1 (&dref, ref, false); | |
047fdd47 | 1326 | } |
119147d1 | 1327 | case BUILT_IN_BCOPY: |
1328 | { | |
1329 | ao_ref dref; | |
1330 | tree size = gimple_call_arg (call, 2); | |
1331 | ao_ref_init_from_ptr_and_size (&dref, | |
1332 | gimple_call_arg (call, 1), | |
1333 | size); | |
1334 | return refs_may_alias_p_1 (&dref, ref, false); | |
1335 | } | |
0d3ca08e | 1336 | /* Allocating memory does not have any side-effects apart from |
1337 | being the definition point for the pointer. */ | |
1338 | case BUILT_IN_MALLOC: | |
4ef43bbd | 1339 | case BUILT_IN_CALLOC: |
1340 | /* Unix98 specifies that errno is set on allocation failure. | |
1341 | Until we properly can track the errno location assume it | |
a29c5f9c | 1342 | is not a local decl but external or anonymous storage in |
1343 | a different translation unit. Also assume it is of | |
1344 | type int as required by the standard. */ | |
1345 | if (flag_errno_math | |
1346 | && TREE_TYPE (base) == integer_type_node) | |
4ef43bbd | 1347 | { |
1348 | struct ptr_info_def *pi; | |
a29c5f9c | 1349 | if (DECL_P (base) |
1350 | && !TREE_STATIC (base)) | |
1351 | return true; | |
182cf5a9 | 1352 | else if ((INDIRECT_REF_P (base) |
1353 | || TREE_CODE (base) == MEM_REF) | |
a29c5f9c | 1354 | && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME |
1355 | && (pi = SSA_NAME_PTR_INFO (TREE_OPERAND (base, 0)))) | |
4ef43bbd | 1356 | return pi->pt.anything || pi->pt.nonlocal; |
1357 | } | |
0d3ca08e | 1358 | return false; |
047fdd47 | 1359 | /* Freeing memory kills the pointed-to memory. More importantly |
1360 | the call has to serve as a barrier for moving loads and stores | |
134899ac | 1361 | across it. */ |
047fdd47 | 1362 | case BUILT_IN_FREE: |
047fdd47 | 1363 | { |
1364 | tree ptr = gimple_call_arg (call, 0); | |
1365 | return ptr_deref_may_alias_ref_p_1 (ptr, ref); | |
1366 | } | |
047fdd47 | 1367 | case BUILT_IN_GAMMA_R: |
1368 | case BUILT_IN_GAMMAF_R: | |
1369 | case BUILT_IN_GAMMAL_R: | |
1370 | case BUILT_IN_LGAMMA_R: | |
1371 | case BUILT_IN_LGAMMAF_R: | |
1372 | case BUILT_IN_LGAMMAL_R: | |
09d9c774 | 1373 | { |
1374 | tree out = gimple_call_arg (call, 1); | |
1375 | if (ptr_deref_may_alias_ref_p_1 (out, ref)) | |
1376 | return true; | |
1377 | if (flag_errno_math) | |
1378 | break; | |
1379 | return false; | |
1380 | } | |
1381 | case BUILT_IN_FREXP: | |
1382 | case BUILT_IN_FREXPF: | |
1383 | case BUILT_IN_FREXPL: | |
047fdd47 | 1384 | case BUILT_IN_MODF: |
1385 | case BUILT_IN_MODFF: | |
1386 | case BUILT_IN_MODFL: | |
1387 | { | |
1388 | tree out = gimple_call_arg (call, 1); | |
1389 | return ptr_deref_may_alias_ref_p_1 (out, ref); | |
1390 | } | |
1391 | case BUILT_IN_REMQUO: | |
1392 | case BUILT_IN_REMQUOF: | |
1393 | case BUILT_IN_REMQUOL: | |
1394 | { | |
1395 | tree out = gimple_call_arg (call, 2); | |
09d9c774 | 1396 | if (ptr_deref_may_alias_ref_p_1 (out, ref)) |
1397 | return true; | |
1398 | if (flag_errno_math) | |
1399 | break; | |
1400 | return false; | |
047fdd47 | 1401 | } |
1402 | case BUILT_IN_SINCOS: | |
1403 | case BUILT_IN_SINCOSF: | |
1404 | case BUILT_IN_SINCOSL: | |
1405 | { | |
1406 | tree sin = gimple_call_arg (call, 1); | |
1407 | tree cos = gimple_call_arg (call, 2); | |
1408 | return (ptr_deref_may_alias_ref_p_1 (sin, ref) | |
1409 | || ptr_deref_may_alias_ref_p_1 (cos, ref)); | |
1410 | } | |
1411 | default: | |
1412 | /* Fallthru to general call handling. */; | |
1413 | } | |
1414 | ||
dd277d48 | 1415 | /* Check if base is a global static variable that is not written |
1416 | by the function. */ | |
047fdd47 | 1417 | if (callee != NULL_TREE |
1418 | && TREE_CODE (base) == VAR_DECL | |
d97be713 | 1419 | && TREE_STATIC (base)) |
4ee9c684 | 1420 | { |
dd277d48 | 1421 | bitmap not_written; |
0eaf9bd7 | 1422 | |
047fdd47 | 1423 | if ((not_written |
1424 | = ipa_reference_get_not_written_global (cgraph_node (callee))) | |
dd277d48 | 1425 | && bitmap_bit_p (not_written, DECL_UID (base))) |
1426 | return false; | |
4ee9c684 | 1427 | } |
4ee9c684 | 1428 | |
cb245216 | 1429 | /* Check if the base variable is call-clobbered. */ |
dd277d48 | 1430 | if (DECL_P (base)) |
cb245216 | 1431 | return pt_solution_includes (gimple_call_clobber_set (call), base); |
182cf5a9 | 1432 | else if ((INDIRECT_REF_P (base) |
1433 | || TREE_CODE (base) == MEM_REF) | |
917f08fa | 1434 | && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME) |
1435 | { | |
1436 | struct ptr_info_def *pi = SSA_NAME_PTR_INFO (TREE_OPERAND (base, 0)); | |
1437 | if (!pi) | |
1438 | return true; | |
1439 | ||
cb245216 | 1440 | return pt_solutions_intersect (gimple_call_clobber_set (call), &pi->pt); |
917f08fa | 1441 | } |
4ee9c684 | 1442 | |
dd277d48 | 1443 | return true; |
1444 | } | |
4ee9c684 | 1445 | |
4debfcfc | 1446 | /* If the call in statement CALL may clobber the memory reference REF |
1447 | return true, otherwise return false. */ | |
1448 | ||
1449 | bool | |
dd277d48 | 1450 | call_may_clobber_ref_p (gimple call, tree ref) |
4ee9c684 | 1451 | { |
3918bd18 | 1452 | bool res; |
1453 | ao_ref r; | |
1454 | ao_ref_init (&r, ref); | |
1455 | res = call_may_clobber_ref_p_1 (call, &r); | |
dd277d48 | 1456 | if (res) |
1457 | ++alias_stats.call_may_clobber_ref_p_may_alias; | |
1458 | else | |
1459 | ++alias_stats.call_may_clobber_ref_p_no_alias; | |
1460 | return res; | |
4ee9c684 | 1461 | } |
94e6573f | 1462 | |
dd277d48 | 1463 | |
1464 | /* If the statement STMT may clobber the memory reference REF return true, | |
1465 | otherwise return false. */ | |
94e6573f | 1466 | |
1467 | bool | |
3918bd18 | 1468 | stmt_may_clobber_ref_p_1 (gimple stmt, ao_ref *ref) |
94e6573f | 1469 | { |
dd277d48 | 1470 | if (is_gimple_call (stmt)) |
1471 | { | |
1472 | tree lhs = gimple_call_lhs (stmt); | |
1473 | if (lhs | |
3918bd18 | 1474 | && !is_gimple_reg (lhs)) |
1475 | { | |
1476 | ao_ref r; | |
1477 | ao_ref_init (&r, lhs); | |
1478 | if (refs_may_alias_p_1 (ref, &r, true)) | |
1479 | return true; | |
1480 | } | |
94e6573f | 1481 | |
3918bd18 | 1482 | return call_may_clobber_ref_p_1 (stmt, ref); |
dd277d48 | 1483 | } |
8e7c2b9c | 1484 | else if (gimple_assign_single_p (stmt)) |
3918bd18 | 1485 | { |
8e7c2b9c | 1486 | tree lhs = gimple_assign_lhs (stmt); |
1487 | if (!is_gimple_reg (lhs)) | |
1488 | { | |
1489 | ao_ref r; | |
1490 | ao_ref_init (&r, gimple_assign_lhs (stmt)); | |
1491 | return refs_may_alias_p_1 (ref, &r, true); | |
1492 | } | |
3918bd18 | 1493 | } |
dd277d48 | 1494 | else if (gimple_code (stmt) == GIMPLE_ASM) |
94e6573f | 1495 | return true; |
1496 | ||
6329636b | 1497 | return false; |
94e6573f | 1498 | } |
2be14d8b | 1499 | |
3918bd18 | 1500 | bool |
1501 | stmt_may_clobber_ref_p (gimple stmt, tree ref) | |
1502 | { | |
1503 | ao_ref r; | |
1504 | ao_ref_init (&r, ref); | |
1505 | return stmt_may_clobber_ref_p_1 (stmt, &r); | |
1506 | } | |
1507 | ||
1508 | ||
dd277d48 | 1509 | /* Walk the virtual use-def chain of VUSE until hitting the virtual operand |
1510 | TARGET or a statement clobbering the memory reference REF in which | |
1511 | case false is returned. The walk starts with VUSE, one argument of PHI. */ | |
1512 | ||
1513 | static bool | |
3918bd18 | 1514 | maybe_skip_until (gimple phi, tree target, ao_ref *ref, |
1515 | tree vuse, bitmap *visited) | |
ac926412 | 1516 | { |
dd277d48 | 1517 | if (!*visited) |
1518 | *visited = BITMAP_ALLOC (NULL); | |
ac926412 | 1519 | |
dd277d48 | 1520 | bitmap_set_bit (*visited, SSA_NAME_VERSION (PHI_RESULT (phi))); |
1521 | ||
1522 | /* Walk until we hit the target. */ | |
1523 | while (vuse != target) | |
ac926412 | 1524 | { |
dd277d48 | 1525 | gimple def_stmt = SSA_NAME_DEF_STMT (vuse); |
1526 | /* Recurse for PHI nodes. */ | |
1527 | if (gimple_code (def_stmt) == GIMPLE_PHI) | |
1528 | { | |
1529 | /* An already visited PHI node ends the walk successfully. */ | |
1530 | if (bitmap_bit_p (*visited, SSA_NAME_VERSION (PHI_RESULT (def_stmt)))) | |
1531 | return true; | |
1532 | vuse = get_continuation_for_phi (def_stmt, ref, visited); | |
1533 | if (!vuse) | |
1534 | return false; | |
1535 | continue; | |
1536 | } | |
1537 | /* A clobbering statement or the end of the IL ends it failing. */ | |
1538 | else if (gimple_nop_p (def_stmt) | |
3918bd18 | 1539 | || stmt_may_clobber_ref_p_1 (def_stmt, ref)) |
dd277d48 | 1540 | return false; |
1541 | vuse = gimple_vuse (def_stmt); | |
ac926412 | 1542 | } |
dd277d48 | 1543 | return true; |
1544 | } | |
ac926412 | 1545 | |
dd277d48 | 1546 | /* Starting from a PHI node for the virtual operand of the memory reference |
1547 | REF find a continuation virtual operand that allows to continue walking | |
1548 | statements dominating PHI skipping only statements that cannot possibly | |
1549 | clobber REF. Returns NULL_TREE if no suitable virtual operand can | |
1550 | be found. */ | |
1551 | ||
7814d418 | 1552 | tree |
3918bd18 | 1553 | get_continuation_for_phi (gimple phi, ao_ref *ref, bitmap *visited) |
dd277d48 | 1554 | { |
1555 | unsigned nargs = gimple_phi_num_args (phi); | |
1556 | ||
1557 | /* Through a single-argument PHI we can simply look through. */ | |
1558 | if (nargs == 1) | |
1559 | return PHI_ARG_DEF (phi, 0); | |
1560 | ||
1561 | /* For two arguments try to skip non-aliasing code until we hit | |
1562 | the phi argument definition that dominates the other one. */ | |
1563 | if (nargs == 2) | |
ac926412 | 1564 | { |
dd277d48 | 1565 | tree arg0 = PHI_ARG_DEF (phi, 0); |
1566 | tree arg1 = PHI_ARG_DEF (phi, 1); | |
1567 | gimple def0 = SSA_NAME_DEF_STMT (arg0); | |
1568 | gimple def1 = SSA_NAME_DEF_STMT (arg1); | |
7814d418 | 1569 | tree common_vuse; |
dd277d48 | 1570 | |
1571 | if (arg0 == arg1) | |
1572 | return arg0; | |
1573 | else if (gimple_nop_p (def0) | |
1574 | || (!gimple_nop_p (def1) | |
1575 | && dominated_by_p (CDI_DOMINATORS, | |
1576 | gimple_bb (def1), gimple_bb (def0)))) | |
1577 | { | |
1578 | if (maybe_skip_until (phi, arg0, ref, arg1, visited)) | |
1579 | return arg0; | |
1580 | } | |
1581 | else if (gimple_nop_p (def1) | |
1582 | || dominated_by_p (CDI_DOMINATORS, | |
1583 | gimple_bb (def0), gimple_bb (def1))) | |
1584 | { | |
1585 | if (maybe_skip_until (phi, arg1, ref, arg0, visited)) | |
1586 | return arg1; | |
1587 | } | |
7814d418 | 1588 | /* Special case of a diamond: |
1589 | MEM_1 = ... | |
1590 | goto (cond) ? L1 : L2 | |
1591 | L1: store1 = ... #MEM_2 = vuse(MEM_1) | |
1592 | goto L3 | |
1593 | L2: store2 = ... #MEM_3 = vuse(MEM_1) | |
1594 | L3: MEM_4 = PHI<MEM_2, MEM_3> | |
1595 | We were called with the PHI at L3, MEM_2 and MEM_3 don't | |
1596 | dominate each other, but still we can easily skip this PHI node | |
1597 | if we recognize that the vuse MEM operand is the same for both, | |
1598 | and that we can skip both statements (they don't clobber us). | |
1599 | This is still linear. Don't use maybe_skip_until, that might | |
1600 | potentially be slow. */ | |
1601 | else if ((common_vuse = gimple_vuse (def0)) | |
1602 | && common_vuse == gimple_vuse (def1)) | |
1603 | { | |
1604 | if (!stmt_may_clobber_ref_p_1 (def0, ref) | |
1605 | && !stmt_may_clobber_ref_p_1 (def1, ref)) | |
1606 | return common_vuse; | |
1607 | } | |
ac926412 | 1608 | } |
dd277d48 | 1609 | |
1610 | return NULL_TREE; | |
ac926412 | 1611 | } |
516849c7 | 1612 | |
dd277d48 | 1613 | /* Based on the memory reference REF and its virtual use VUSE call |
1614 | WALKER for each virtual use that is equivalent to VUSE, including VUSE | |
1615 | itself. That is, for each virtual use for which its defining statement | |
1616 | does not clobber REF. | |
e683de6d | 1617 | |
dd277d48 | 1618 | WALKER is called with REF, the current virtual use and DATA. If |
1619 | WALKER returns non-NULL the walk stops and its result is returned. | |
1620 | At the end of a non-successful walk NULL is returned. | |
3857274c | 1621 | |
d8021dea | 1622 | TRANSLATE if non-NULL is called with a pointer to REF, the virtual |
1623 | use which definition is a statement that may clobber REF and DATA. | |
1624 | If TRANSLATE returns (void *)-1 the walk stops and NULL is returned. | |
1625 | If TRANSLATE returns non-NULL the walk stops and its result is returned. | |
1626 | If TRANSLATE returns NULL the walk continues and TRANSLATE is supposed | |
1627 | to adjust REF and *DATA to make that valid. | |
1628 | ||
dd277d48 | 1629 | TODO: Cache the vector of equivalent vuses per ref, vuse pair. */ |
1630 | ||
1631 | void * | |
3918bd18 | 1632 | walk_non_aliased_vuses (ao_ref *ref, tree vuse, |
1633 | void *(*walker)(ao_ref *, tree, void *), | |
1634 | void *(*translate)(ao_ref *, tree, void *), void *data) | |
3857274c | 1635 | { |
dd277d48 | 1636 | bitmap visited = NULL; |
1637 | void *res; | |
1638 | ||
02c74b9b | 1639 | timevar_push (TV_ALIAS_STMT_WALK); |
1640 | ||
dd277d48 | 1641 | do |
1642 | { | |
1643 | gimple def_stmt; | |
3857274c | 1644 | |
02c74b9b | 1645 | /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */ |
dd277d48 | 1646 | res = (*walker) (ref, vuse, data); |
1647 | if (res) | |
1648 | break; | |
3857274c | 1649 | |
dd277d48 | 1650 | def_stmt = SSA_NAME_DEF_STMT (vuse); |
1651 | if (gimple_nop_p (def_stmt)) | |
1652 | break; | |
1653 | else if (gimple_code (def_stmt) == GIMPLE_PHI) | |
1654 | vuse = get_continuation_for_phi (def_stmt, ref, &visited); | |
1655 | else | |
1656 | { | |
3918bd18 | 1657 | if (stmt_may_clobber_ref_p_1 (def_stmt, ref)) |
d8021dea | 1658 | { |
1659 | if (!translate) | |
1660 | break; | |
3918bd18 | 1661 | res = (*translate) (ref, vuse, data); |
d8021dea | 1662 | /* Failed lookup and translation. */ |
1663 | if (res == (void *)-1) | |
1664 | { | |
1665 | res = NULL; | |
1666 | break; | |
1667 | } | |
1668 | /* Lookup succeeded. */ | |
1669 | else if (res != NULL) | |
1670 | break; | |
1671 | /* Translation succeeded, continue walking. */ | |
1672 | } | |
dd277d48 | 1673 | vuse = gimple_vuse (def_stmt); |
1674 | } | |
1675 | } | |
1676 | while (vuse); | |
ac926412 | 1677 | |
dd277d48 | 1678 | if (visited) |
1679 | BITMAP_FREE (visited); | |
ac926412 | 1680 | |
02c74b9b | 1681 | timevar_pop (TV_ALIAS_STMT_WALK); |
1682 | ||
dd277d48 | 1683 | return res; |
3857274c | 1684 | } |
1685 | ||
604eef2c | 1686 | |
dd277d48 | 1687 | /* Based on the memory reference REF call WALKER for each vdef which |
1688 | defining statement may clobber REF, starting with VDEF. If REF | |
1689 | is NULL_TREE, each defining statement is visited. | |
1690 | ||
1691 | WALKER is called with REF, the current vdef and DATA. If WALKER | |
1692 | returns true the walk is stopped, otherwise it continues. | |
1693 | ||
1694 | At PHI nodes walk_aliased_vdefs forks into one walk for reach | |
1695 | PHI argument (but only one walk continues on merge points), the | |
1696 | return value is true if any of the walks was successful. | |
1697 | ||
1698 | The function returns the number of statements walked. */ | |
604eef2c | 1699 | |
1700 | static unsigned int | |
1daead67 | 1701 | walk_aliased_vdefs_1 (ao_ref *ref, tree vdef, |
1702 | bool (*walker)(ao_ref *, tree, void *), void *data, | |
dd277d48 | 1703 | bitmap *visited, unsigned int cnt) |
604eef2c | 1704 | { |
dd277d48 | 1705 | do |
1706 | { | |
1707 | gimple def_stmt = SSA_NAME_DEF_STMT (vdef); | |
604eef2c | 1708 | |
dd277d48 | 1709 | if (*visited |
1710 | && !bitmap_set_bit (*visited, SSA_NAME_VERSION (vdef))) | |
1711 | return cnt; | |
1712 | ||
1713 | if (gimple_nop_p (def_stmt)) | |
1714 | return cnt; | |
1715 | else if (gimple_code (def_stmt) == GIMPLE_PHI) | |
1716 | { | |
1717 | unsigned i; | |
1718 | if (!*visited) | |
1719 | *visited = BITMAP_ALLOC (NULL); | |
1720 | for (i = 0; i < gimple_phi_num_args (def_stmt); ++i) | |
1721 | cnt += walk_aliased_vdefs_1 (ref, gimple_phi_arg_def (def_stmt, i), | |
1722 | walker, data, visited, 0); | |
1723 | return cnt; | |
1724 | } | |
1725 | ||
02c74b9b | 1726 | /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */ |
dd277d48 | 1727 | cnt++; |
1728 | if ((!ref | |
1daead67 | 1729 | || stmt_may_clobber_ref_p_1 (def_stmt, ref)) |
dd277d48 | 1730 | && (*walker) (ref, vdef, data)) |
1731 | return cnt; | |
1732 | ||
1733 | vdef = gimple_vuse (def_stmt); | |
1734 | } | |
1735 | while (1); | |
604eef2c | 1736 | } |
1737 | ||
dd277d48 | 1738 | unsigned int |
1daead67 | 1739 | walk_aliased_vdefs (ao_ref *ref, tree vdef, |
1740 | bool (*walker)(ao_ref *, tree, void *), void *data, | |
dd277d48 | 1741 | bitmap *visited) |
df3f0669 | 1742 | { |
dd277d48 | 1743 | bitmap local_visited = NULL; |
1744 | unsigned int ret; | |
1745 | ||
02c74b9b | 1746 | timevar_push (TV_ALIAS_STMT_WALK); |
1747 | ||
dd277d48 | 1748 | ret = walk_aliased_vdefs_1 (ref, vdef, walker, data, |
1749 | visited ? visited : &local_visited, 0); | |
1750 | if (local_visited) | |
1751 | BITMAP_FREE (local_visited); | |
1752 | ||
02c74b9b | 1753 | timevar_pop (TV_ALIAS_STMT_WALK); |
1754 | ||
dd277d48 | 1755 | return ret; |
1756 | } | |
1757 |