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ea0cb7ae | 1 | /* Alias analysis for GNU C |
d4473c84 | 2 | Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, |
cfaf579d | 3 | 2007, 2008, 2009 Free Software Foundation, Inc. |
ea0cb7ae | 4 | Contributed by John Carr (jfc@mit.edu). |
5 | ||
f12b58b3 | 6 | This file is part of GCC. |
ea0cb7ae | 7 | |
f12b58b3 | 8 | GCC is free software; you can redistribute it and/or modify it under |
9 | the terms of the GNU General Public License as published by the Free | |
8c4c00c1 | 10 | Software Foundation; either version 3, or (at your option) any later |
f12b58b3 | 11 | version. |
ea0cb7ae | 12 | |
f12b58b3 | 13 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY |
14 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
15 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
16 | for more details. | |
ea0cb7ae | 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/>. */ | |
ea0cb7ae | 21 | |
22 | #include "config.h" | |
405711de | 23 | #include "system.h" |
805e22b2 | 24 | #include "coretypes.h" |
25 | #include "tm.h" | |
ea0cb7ae | 26 | #include "rtl.h" |
142131ed | 27 | #include "tree.h" |
7953c610 | 28 | #include "tm_p.h" |
0a893c29 | 29 | #include "function.h" |
4c74e6d9 | 30 | #include "alias.h" |
31 | #include "emit-rtl.h" | |
ea0cb7ae | 32 | #include "regs.h" |
33 | #include "hard-reg-set.h" | |
080f162d | 34 | #include "basic-block.h" |
ea0cb7ae | 35 | #include "flags.h" |
a068b2a9 | 36 | #include "output.h" |
ce1fd7fc | 37 | #include "toplev.h" |
1617c276 | 38 | #include "cselib.h" |
a5b1863e | 39 | #include "splay-tree.h" |
c2e94b25 | 40 | #include "ggc.h" |
b0278d39 | 41 | #include "langhooks.h" |
376c21d1 | 42 | #include "timevar.h" |
4f8e9d5c | 43 | #include "target.h" |
28992b23 | 44 | #include "cgraph.h" |
56bbdce4 | 45 | #include "varray.h" |
77fce4cd | 46 | #include "tree-pass.h" |
f7d118a9 | 47 | #include "ipa-type-escape.h" |
3072d30e | 48 | #include "df.h" |
3a443843 | 49 | #include "tree-ssa-alias.h" |
50 | #include "pointer-set.h" | |
51 | #include "tree-flow.h" | |
f7d118a9 | 52 | |
53 | /* The aliasing API provided here solves related but different problems: | |
54 | ||
a0c938f0 | 55 | Say there exists (in c) |
f7d118a9 | 56 | |
57 | struct X { | |
58 | struct Y y1; | |
59 | struct Z z2; | |
60 | } x1, *px1, *px2; | |
61 | ||
62 | struct Y y2, *py; | |
63 | struct Z z2, *pz; | |
64 | ||
65 | ||
66 | py = &px1.y1; | |
67 | px2 = &x1; | |
68 | ||
69 | Consider the four questions: | |
70 | ||
71 | Can a store to x1 interfere with px2->y1? | |
72 | Can a store to x1 interfere with px2->z2? | |
73 | (*px2).z2 | |
74 | Can a store to x1 change the value pointed to by with py? | |
75 | Can a store to x1 change the value pointed to by with pz? | |
76 | ||
77 | The answer to these questions can be yes, yes, yes, and maybe. | |
78 | ||
79 | The first two questions can be answered with a simple examination | |
80 | of the type system. If structure X contains a field of type Y then | |
81 | a store thru a pointer to an X can overwrite any field that is | |
82 | contained (recursively) in an X (unless we know that px1 != px2). | |
83 | ||
84 | The last two of the questions can be solved in the same way as the | |
85 | first two questions but this is too conservative. The observation | |
86 | is that in some cases analysis we can know if which (if any) fields | |
87 | are addressed and if those addresses are used in bad ways. This | |
88 | analysis may be language specific. In C, arbitrary operations may | |
89 | be applied to pointers. However, there is some indication that | |
90 | this may be too conservative for some C++ types. | |
91 | ||
92 | The pass ipa-type-escape does this analysis for the types whose | |
a0c938f0 | 93 | instances do not escape across the compilation boundary. |
f7d118a9 | 94 | |
95 | Historically in GCC, these two problems were combined and a single | |
96 | data structure was used to represent the solution to these | |
97 | problems. We now have two similar but different data structures, | |
98 | The data structure to solve the last two question is similar to the | |
99 | first, but does not contain have the fields in it whose address are | |
100 | never taken. For types that do escape the compilation unit, the | |
101 | data structures will have identical information. | |
102 | */ | |
a5b1863e | 103 | |
104 | /* The alias sets assigned to MEMs assist the back-end in determining | |
105 | which MEMs can alias which other MEMs. In general, two MEMs in | |
5badbbc0 | 106 | different alias sets cannot alias each other, with one important |
107 | exception. Consider something like: | |
a5b1863e | 108 | |
8e2ef041 | 109 | struct S { int i; double d; }; |
a5b1863e | 110 | |
111 | a store to an `S' can alias something of either type `int' or type | |
112 | `double'. (However, a store to an `int' cannot alias a `double' | |
113 | and vice versa.) We indicate this via a tree structure that looks | |
114 | like: | |
a0c938f0 | 115 | struct S |
116 | / \ | |
a5b1863e | 117 | / \ |
a0c938f0 | 118 | |/_ _\| |
119 | int double | |
a5b1863e | 120 | |
5badbbc0 | 121 | (The arrows are directed and point downwards.) |
122 | In this situation we say the alias set for `struct S' is the | |
123 | `superset' and that those for `int' and `double' are `subsets'. | |
124 | ||
f7c44134 | 125 | To see whether two alias sets can point to the same memory, we must |
126 | see if either alias set is a subset of the other. We need not trace | |
d716ce75 | 127 | past immediate descendants, however, since we propagate all |
f7c44134 | 128 | grandchildren up one level. |
a5b1863e | 129 | |
130 | Alias set zero is implicitly a superset of all other alias sets. | |
131 | However, this is no actual entry for alias set zero. It is an | |
132 | error to attempt to explicitly construct a subset of zero. */ | |
133 | ||
26dbec0a | 134 | struct GTY(()) alias_set_entry_d { |
a5b1863e | 135 | /* The alias set number, as stored in MEM_ALIAS_SET. */ |
32c2fdea | 136 | alias_set_type alias_set; |
a5b1863e | 137 | |
1e020227 | 138 | /* Nonzero if would have a child of zero: this effectively makes this |
139 | alias set the same as alias set zero. */ | |
140 | int has_zero_child; | |
141 | ||
a5b1863e | 142 | /* The children of the alias set. These are not just the immediate |
d716ce75 | 143 | children, but, in fact, all descendants. So, if we have: |
a5b1863e | 144 | |
9342ee68 | 145 | struct T { struct S s; float f; } |
a5b1863e | 146 | |
147 | continuing our example above, the children here will be all of | |
148 | `int', `double', `float', and `struct S'. */ | |
318dcdd8 | 149 | splay_tree GTY((param1_is (int), param2_is (int))) children; |
318dcdd8 | 150 | }; |
26dbec0a | 151 | typedef struct alias_set_entry_d *alias_set_entry; |
ea0cb7ae | 152 | |
7ecb5bb2 | 153 | static int rtx_equal_for_memref_p (const_rtx, const_rtx); |
aecda0d6 | 154 | static int memrefs_conflict_p (int, rtx, int, rtx, HOST_WIDE_INT); |
81a410b1 | 155 | static void record_set (rtx, const_rtx, void *); |
aecda0d6 | 156 | static int base_alias_check (rtx, rtx, enum machine_mode, |
157 | enum machine_mode); | |
158 | static rtx find_base_value (rtx); | |
52d07779 | 159 | static int mems_in_disjoint_alias_sets_p (const_rtx, const_rtx); |
aecda0d6 | 160 | static int insert_subset_children (splay_tree_node, void*); |
32c2fdea | 161 | static alias_set_entry get_alias_set_entry (alias_set_type); |
52d07779 | 162 | static const_rtx fixed_scalar_and_varying_struct_p (const_rtx, const_rtx, rtx, rtx, |
163 | bool (*) (const_rtx, bool)); | |
164 | static int aliases_everything_p (const_rtx); | |
165 | static bool nonoverlapping_component_refs_p (const_tree, const_tree); | |
aecda0d6 | 166 | static tree decl_for_component_ref (tree); |
167 | static rtx adjust_offset_for_component_ref (tree, rtx); | |
52d07779 | 168 | static int write_dependence_p (const_rtx, const_rtx, int); |
aecda0d6 | 169 | |
a80f1c6c | 170 | static void memory_modified_1 (rtx, const_rtx, void *); |
ea0cb7ae | 171 | |
172 | /* Set up all info needed to perform alias analysis on memory references. */ | |
173 | ||
083a2b5e | 174 | /* Returns the size in bytes of the mode of X. */ |
ea0cb7ae | 175 | #define SIZE_FOR_MODE(X) (GET_MODE_SIZE (GET_MODE (X))) |
176 | ||
b5ba9f3a | 177 | /* Returns nonzero if MEM1 and MEM2 do not alias because they are in |
a068b2a9 | 178 | different alias sets. We ignore alias sets in functions making use |
179 | of variable arguments because the va_arg macros on some systems are | |
180 | not legal ANSI C. */ | |
181 | #define DIFFERENT_ALIAS_SETS_P(MEM1, MEM2) \ | |
a5b1863e | 182 | mems_in_disjoint_alias_sets_p (MEM1, MEM2) |
b5ba9f3a | 183 | |
37b864db | 184 | /* Cap the number of passes we make over the insns propagating alias |
5badbbc0 | 185 | information through set chains. 10 is a completely arbitrary choice. */ |
37b864db | 186 | #define MAX_ALIAS_LOOP_PASSES 10 |
9342ee68 | 187 | |
ea0cb7ae | 188 | /* reg_base_value[N] gives an address to which register N is related. |
189 | If all sets after the first add or subtract to the current value | |
190 | or otherwise modify it so it does not point to a different top level | |
191 | object, reg_base_value[N] is equal to the address part of the source | |
e7c893ba | 192 | of the first set. |
193 | ||
194 | A base address can be an ADDRESS, SYMBOL_REF, or LABEL_REF. ADDRESS | |
195 | expressions represent certain special values: function arguments and | |
9342ee68 | 196 | the stack, frame, and argument pointers. |
3a935f06 | 197 | |
198 | The contents of an ADDRESS is not normally used, the mode of the | |
199 | ADDRESS determines whether the ADDRESS is a function argument or some | |
200 | other special value. Pointer equality, not rtx_equal_p, determines whether | |
201 | two ADDRESS expressions refer to the same base address. | |
202 | ||
203 | The only use of the contents of an ADDRESS is for determining if the | |
204 | current function performs nonlocal memory memory references for the | |
205 | purposes of marking the function as a constant function. */ | |
e7c893ba | 206 | |
980f3285 | 207 | static GTY(()) VEC(rtx,gc) *reg_base_value; |
c2e94b25 | 208 | static rtx *new_reg_base_value; |
e5b19a8c | 209 | |
210 | /* We preserve the copy of old array around to avoid amount of garbage | |
211 | produced. About 8% of garbage produced were attributed to this | |
212 | array. */ | |
980f3285 | 213 | static GTY((deletable)) VEC(rtx,gc) *old_reg_base_value; |
083a2b5e | 214 | |
0c7f5242 | 215 | /* Static hunks of RTL used by the aliasing code; these are initialized |
216 | once per function to avoid unnecessary RTL allocations. */ | |
217 | static GTY (()) rtx static_reg_base_value[FIRST_PSEUDO_REGISTER]; | |
218 | ||
980f3285 | 219 | #define REG_BASE_VALUE(X) \ |
220 | (REGNO (X) < VEC_length (rtx, reg_base_value) \ | |
221 | ? VEC_index (rtx, reg_base_value, REGNO (X)) : 0) | |
ea0cb7ae | 222 | |
73f5c1e3 | 223 | /* Vector indexed by N giving the initial (unchanging) value known for |
12cb06ad | 224 | pseudo-register N. This array is initialized in init_alias_analysis, |
225 | and does not change until end_alias_analysis is called. */ | |
226 | static GTY((length("reg_known_value_size"))) rtx *reg_known_value; | |
ea0cb7ae | 227 | |
228 | /* Indicates number of valid entries in reg_known_value. */ | |
12cb06ad | 229 | static GTY(()) unsigned int reg_known_value_size; |
ea0cb7ae | 230 | |
231 | /* Vector recording for each reg_known_value whether it is due to a | |
232 | REG_EQUIV note. Future passes (viz., reload) may replace the | |
233 | pseudo with the equivalent expression and so we account for the | |
5badbbc0 | 234 | dependences that would be introduced if that happens. |
235 | ||
236 | The REG_EQUIV notes created in assign_parms may mention the arg | |
237 | pointer, and there are explicit insns in the RTL that modify the | |
238 | arg pointer. Thus we must ensure that such insns don't get | |
239 | scheduled across each other because that would invalidate the | |
240 | REG_EQUIV notes. One could argue that the REG_EQUIV notes are | |
241 | wrong, but solving the problem in the scheduler will likely give | |
242 | better code, so we do it here. */ | |
12cb06ad | 243 | static bool *reg_known_equiv_p; |
ea0cb7ae | 244 | |
e7c893ba | 245 | /* True when scanning insns from the start of the rtl to the |
246 | NOTE_INSN_FUNCTION_BEG note. */ | |
e5be0cc6 | 247 | static bool copying_arguments; |
ea0cb7ae | 248 | |
8b435339 | 249 | DEF_VEC_P(alias_set_entry); |
250 | DEF_VEC_ALLOC_P(alias_set_entry,gc); | |
251 | ||
a5b1863e | 252 | /* The splay-tree used to store the various alias set entries. */ |
8b435339 | 253 | static GTY (()) VEC(alias_set_entry,gc) *alias_sets; |
5badbbc0 | 254 | \f |
3a443843 | 255 | /* Build a decomposed reference object for querying the alias-oracle |
256 | from the MEM rtx and store it in *REF. | |
257 | Returns false if MEM is not suitable for the alias-oracle. */ | |
258 | ||
259 | static bool | |
260 | ao_ref_from_mem (ao_ref *ref, const_rtx mem) | |
261 | { | |
262 | tree expr = MEM_EXPR (mem); | |
263 | tree base; | |
264 | ||
265 | if (!expr) | |
266 | return false; | |
267 | ||
3804203d | 268 | /* If MEM_OFFSET or MEM_SIZE are NULL punt. */ |
269 | if (!MEM_OFFSET (mem) | |
270 | || !MEM_SIZE (mem)) | |
271 | return false; | |
272 | ||
3a443843 | 273 | ao_ref_init (ref, expr); |
274 | ||
275 | /* Get the base of the reference and see if we have to reject or | |
276 | adjust it. */ | |
277 | base = ao_ref_base (ref); | |
278 | if (base == NULL_TREE) | |
279 | return false; | |
280 | ||
281 | /* If this is a pointer dereference of a non-SSA_NAME punt. | |
282 | ??? We could replace it with a pointer to anything. */ | |
283 | if (INDIRECT_REF_P (base) | |
284 | && TREE_CODE (TREE_OPERAND (base, 0)) != SSA_NAME) | |
285 | return false; | |
286 | ||
0f2b32ac | 287 | /* The tree oracle doesn't like to have these. */ |
288 | if (TREE_CODE (base) == FUNCTION_DECL | |
289 | || TREE_CODE (base) == LABEL_DECL) | |
290 | return false; | |
291 | ||
3a443843 | 292 | /* If this is a reference based on a partitioned decl replace the |
293 | base with an INDIRECT_REF of the pointer representative we | |
294 | created during stack slot partitioning. */ | |
295 | if (TREE_CODE (base) == VAR_DECL | |
296 | && ! TREE_STATIC (base) | |
297 | && cfun->gimple_df->decls_to_pointers != NULL) | |
298 | { | |
299 | void *namep; | |
300 | namep = pointer_map_contains (cfun->gimple_df->decls_to_pointers, base); | |
301 | if (namep) | |
302 | { | |
303 | ref->base_alias_set = get_alias_set (base); | |
304 | ref->base = build1 (INDIRECT_REF, TREE_TYPE (base), *(tree *)namep); | |
305 | } | |
306 | } | |
307 | ||
308 | ref->ref_alias_set = MEM_ALIAS_SET (mem); | |
309 | ||
3804203d | 310 | /* If the base decl is a parameter we can have negative MEM_OFFSET in |
311 | case of promoted subregs on bigendian targets. Trust the MEM_EXPR | |
312 | here. */ | |
313 | if (INTVAL (MEM_OFFSET (mem)) < 0 | |
314 | && ((INTVAL (MEM_SIZE (mem)) + INTVAL (MEM_OFFSET (mem))) | |
315 | * BITS_PER_UNIT) == ref->size) | |
316 | return true; | |
317 | ||
318 | ref->offset += INTVAL (MEM_OFFSET (mem)) * BITS_PER_UNIT; | |
319 | ref->size = INTVAL (MEM_SIZE (mem)) * BITS_PER_UNIT; | |
320 | ||
321 | /* The MEM may extend into adjacent fields, so adjust max_size if | |
322 | necessary. */ | |
323 | if (ref->max_size != -1 | |
324 | && ref->size > ref->max_size) | |
325 | ref->max_size = ref->size; | |
326 | ||
327 | /* If MEM_OFFSET and MEM_SIZE get us outside of the base object of | |
328 | the MEM_EXPR punt. This happens for STRICT_ALIGNMENT targets a lot. */ | |
329 | if (MEM_EXPR (mem) != get_spill_slot_decl (false) | |
330 | && (ref->offset < 0 | |
331 | || (DECL_P (ref->base) | |
332 | && (!host_integerp (DECL_SIZE (ref->base), 1) | |
333 | || (TREE_INT_CST_LOW (DECL_SIZE ((ref->base))) | |
334 | < (unsigned HOST_WIDE_INT)(ref->offset + ref->size)))))) | |
335 | return false; | |
3a443843 | 336 | |
337 | return true; | |
338 | } | |
339 | ||
340 | /* Query the alias-oracle on whether the two memory rtx X and MEM may | |
341 | alias. If TBAA_P is set also apply TBAA. Returns true if the | |
342 | two rtxen may alias, false otherwise. */ | |
343 | ||
344 | static bool | |
345 | rtx_refs_may_alias_p (const_rtx x, const_rtx mem, bool tbaa_p) | |
346 | { | |
347 | ao_ref ref1, ref2; | |
348 | ||
349 | if (!ao_ref_from_mem (&ref1, x) | |
350 | || !ao_ref_from_mem (&ref2, mem)) | |
351 | return true; | |
352 | ||
353 | return refs_may_alias_p_1 (&ref1, &ref2, tbaa_p); | |
354 | } | |
355 | ||
a5b1863e | 356 | /* Returns a pointer to the alias set entry for ALIAS_SET, if there is |
357 | such an entry, or NULL otherwise. */ | |
358 | ||
56bbdce4 | 359 | static inline alias_set_entry |
32c2fdea | 360 | get_alias_set_entry (alias_set_type alias_set) |
a5b1863e | 361 | { |
8b435339 | 362 | return VEC_index (alias_set_entry, alias_sets, alias_set); |
a5b1863e | 363 | } |
364 | ||
5badbbc0 | 365 | /* Returns nonzero if the alias sets for MEM1 and MEM2 are such that |
366 | the two MEMs cannot alias each other. */ | |
a5b1863e | 367 | |
56bbdce4 | 368 | static inline int |
52d07779 | 369 | mems_in_disjoint_alias_sets_p (const_rtx mem1, const_rtx mem2) |
a5b1863e | 370 | { |
a5b1863e | 371 | /* Perform a basic sanity check. Namely, that there are no alias sets |
372 | if we're not using strict aliasing. This helps to catch bugs | |
373 | whereby someone uses PUT_CODE, but doesn't clear MEM_ALIAS_SET, or | |
374 | where a MEM is allocated in some way other than by the use of | |
375 | gen_rtx_MEM, and the MEM_ALIAS_SET is not cleared. If we begin to | |
376 | use alias sets to indicate that spilled registers cannot alias each | |
377 | other, we might need to remove this check. */ | |
64db345d | 378 | gcc_assert (flag_strict_aliasing |
379 | || (!MEM_ALIAS_SET (mem1) && !MEM_ALIAS_SET (mem2))); | |
a5b1863e | 380 | |
387bc205 | 381 | return ! alias_sets_conflict_p (MEM_ALIAS_SET (mem1), MEM_ALIAS_SET (mem2)); |
382 | } | |
a5b1863e | 383 | |
387bc205 | 384 | /* Insert the NODE into the splay tree given by DATA. Used by |
385 | record_alias_subset via splay_tree_foreach. */ | |
386 | ||
387 | static int | |
aecda0d6 | 388 | insert_subset_children (splay_tree_node node, void *data) |
387bc205 | 389 | { |
390 | splay_tree_insert ((splay_tree) data, node->key, node->value); | |
391 | ||
392 | return 0; | |
393 | } | |
394 | ||
7d1f52b2 | 395 | /* Return true if the first alias set is a subset of the second. */ |
396 | ||
397 | bool | |
32c2fdea | 398 | alias_set_subset_of (alias_set_type set1, alias_set_type set2) |
7d1f52b2 | 399 | { |
400 | alias_set_entry ase; | |
401 | ||
402 | /* Everything is a subset of the "aliases everything" set. */ | |
403 | if (set2 == 0) | |
404 | return true; | |
405 | ||
406 | /* Otherwise, check if set1 is a subset of set2. */ | |
407 | ase = get_alias_set_entry (set2); | |
408 | if (ase != 0 | |
6c711ccf | 409 | && ((ase->has_zero_child && set1 == 0) |
410 | || splay_tree_lookup (ase->children, | |
411 | (splay_tree_key) set1))) | |
7d1f52b2 | 412 | return true; |
413 | return false; | |
414 | } | |
415 | ||
387bc205 | 416 | /* Return 1 if the two specified alias sets may conflict. */ |
417 | ||
418 | int | |
32c2fdea | 419 | alias_sets_conflict_p (alias_set_type set1, alias_set_type set2) |
387bc205 | 420 | { |
421 | alias_set_entry ase; | |
422 | ||
879f881c | 423 | /* The easy case. */ |
424 | if (alias_sets_must_conflict_p (set1, set2)) | |
387bc205 | 425 | return 1; |
a5b1863e | 426 | |
f7c44134 | 427 | /* See if the first alias set is a subset of the second. */ |
387bc205 | 428 | ase = get_alias_set_entry (set1); |
851dfbff | 429 | if (ase != 0 |
430 | && (ase->has_zero_child | |
431 | || splay_tree_lookup (ase->children, | |
387bc205 | 432 | (splay_tree_key) set2))) |
433 | return 1; | |
a5b1863e | 434 | |
435 | /* Now do the same, but with the alias sets reversed. */ | |
387bc205 | 436 | ase = get_alias_set_entry (set2); |
851dfbff | 437 | if (ase != 0 |
438 | && (ase->has_zero_child | |
439 | || splay_tree_lookup (ase->children, | |
387bc205 | 440 | (splay_tree_key) set1))) |
441 | return 1; | |
a5b1863e | 442 | |
387bc205 | 443 | /* The two alias sets are distinct and neither one is the |
879f881c | 444 | child of the other. Therefore, they cannot conflict. */ |
387bc205 | 445 | return 0; |
a5b1863e | 446 | } |
c1628b55 | 447 | |
6e93a4c8 | 448 | static int |
449 | walk_mems_2 (rtx *x, rtx mem) | |
450 | { | |
451 | if (MEM_P (*x)) | |
452 | { | |
453 | if (alias_sets_conflict_p (MEM_ALIAS_SET(*x), MEM_ALIAS_SET(mem))) | |
454 | return 1; | |
455 | ||
456 | return -1; | |
457 | } | |
458 | return 0; | |
459 | } | |
460 | ||
461 | static int | |
462 | walk_mems_1 (rtx *x, rtx *pat) | |
463 | { | |
464 | if (MEM_P (*x)) | |
465 | { | |
466 | /* Visit all MEMs in *PAT and check indepedence. */ | |
467 | if (for_each_rtx (pat, (rtx_function) walk_mems_2, *x)) | |
468 | /* Indicate that dependence was determined and stop traversal. */ | |
469 | return 1; | |
470 | ||
471 | return -1; | |
472 | } | |
473 | return 0; | |
474 | } | |
475 | ||
476 | /* Return 1 if two specified instructions have mem expr with conflict alias sets*/ | |
477 | bool | |
478 | insn_alias_sets_conflict_p (rtx insn1, rtx insn2) | |
479 | { | |
480 | /* For each pair of MEMs in INSN1 and INSN2 check their independence. */ | |
481 | return for_each_rtx (&PATTERN (insn1), (rtx_function) walk_mems_1, | |
482 | &PATTERN (insn2)); | |
483 | } | |
484 | ||
879f881c | 485 | /* Return 1 if the two specified alias sets will always conflict. */ |
c1628b55 | 486 | |
487 | int | |
32c2fdea | 488 | alias_sets_must_conflict_p (alias_set_type set1, alias_set_type set2) |
c1628b55 | 489 | { |
490 | if (set1 == 0 || set2 == 0 || set1 == set2) | |
491 | return 1; | |
492 | ||
493 | return 0; | |
494 | } | |
495 | ||
387bc205 | 496 | /* Return 1 if any MEM object of type T1 will always conflict (using the |
497 | dependency routines in this file) with any MEM object of type T2. | |
498 | This is used when allocating temporary storage. If T1 and/or T2 are | |
499 | NULL_TREE, it means we know nothing about the storage. */ | |
500 | ||
501 | int | |
aecda0d6 | 502 | objects_must_conflict_p (tree t1, tree t2) |
387bc205 | 503 | { |
32c2fdea | 504 | alias_set_type set1, set2; |
2bedf233 | 505 | |
218eb8d0 | 506 | /* If neither has a type specified, we don't know if they'll conflict |
507 | because we may be using them to store objects of various types, for | |
508 | example the argument and local variables areas of inlined functions. */ | |
8f2ba9c9 | 509 | if (t1 == 0 && t2 == 0) |
218eb8d0 | 510 | return 0; |
511 | ||
387bc205 | 512 | /* If they are the same type, they must conflict. */ |
513 | if (t1 == t2 | |
514 | /* Likewise if both are volatile. */ | |
515 | || (t1 != 0 && TYPE_VOLATILE (t1) && t2 != 0 && TYPE_VOLATILE (t2))) | |
516 | return 1; | |
517 | ||
2bedf233 | 518 | set1 = t1 ? get_alias_set (t1) : 0; |
519 | set2 = t2 ? get_alias_set (t2) : 0; | |
387bc205 | 520 | |
879f881c | 521 | /* We can't use alias_sets_conflict_p because we must make sure |
522 | that every subtype of t1 will conflict with every subtype of | |
2bedf233 | 523 | t2 for which a pair of subobjects of these respective subtypes |
524 | overlaps on the stack. */ | |
879f881c | 525 | return alias_sets_must_conflict_p (set1, set2); |
387bc205 | 526 | } |
527 | \f | |
2b02580f | 528 | /* Return true if all nested component references handled by |
529 | get_inner_reference in T are such that we should use the alias set | |
530 | provided by the object at the heart of T. | |
531 | ||
532 | This is true for non-addressable components (which don't have their | |
533 | own alias set), as well as components of objects in alias set zero. | |
534 | This later point is a special case wherein we wish to override the | |
535 | alias set used by the component, but we don't have per-FIELD_DECL | |
536 | assignable alias sets. */ | |
537 | ||
538 | bool | |
1f1872fd | 539 | component_uses_parent_alias_set (const_tree t) |
bd32979f | 540 | { |
1f9b622b | 541 | while (1) |
542 | { | |
2b02580f | 543 | /* If we're at the end, it vacuously uses its own alias set. */ |
1f9b622b | 544 | if (!handled_component_p (t)) |
2b02580f | 545 | return false; |
1f9b622b | 546 | |
547 | switch (TREE_CODE (t)) | |
548 | { | |
549 | case COMPONENT_REF: | |
550 | if (DECL_NONADDRESSABLE_P (TREE_OPERAND (t, 1))) | |
2b02580f | 551 | return true; |
1f9b622b | 552 | break; |
553 | ||
554 | case ARRAY_REF: | |
555 | case ARRAY_RANGE_REF: | |
556 | if (TYPE_NONALIASED_COMPONENT (TREE_TYPE (TREE_OPERAND (t, 0)))) | |
2b02580f | 557 | return true; |
1f9b622b | 558 | break; |
559 | ||
560 | case REALPART_EXPR: | |
561 | case IMAGPART_EXPR: | |
562 | break; | |
563 | ||
564 | default: | |
565 | /* Bitfields and casts are never addressable. */ | |
2b02580f | 566 | return true; |
1f9b622b | 567 | } |
568 | ||
569 | t = TREE_OPERAND (t, 0); | |
2b02580f | 570 | if (get_alias_set (TREE_TYPE (t)) == 0) |
571 | return true; | |
1f9b622b | 572 | } |
bd32979f | 573 | } |
574 | ||
dd277d48 | 575 | /* Return the alias set for the memory pointed to by T, which may be |
576 | either a type or an expression. Return -1 if there is nothing | |
577 | special about dereferencing T. */ | |
578 | ||
579 | static alias_set_type | |
580 | get_deref_alias_set_1 (tree t) | |
581 | { | |
582 | /* If we're not doing any alias analysis, just assume everything | |
583 | aliases everything else. */ | |
584 | if (!flag_strict_aliasing) | |
585 | return 0; | |
586 | ||
8115f0af | 587 | /* All we care about is the type. */ |
dd277d48 | 588 | if (! TYPE_P (t)) |
8115f0af | 589 | t = TREE_TYPE (t); |
dd277d48 | 590 | |
591 | /* If we have an INDIRECT_REF via a void pointer, we don't | |
592 | know anything about what that might alias. Likewise if the | |
593 | pointer is marked that way. */ | |
594 | if (TREE_CODE (TREE_TYPE (t)) == VOID_TYPE | |
595 | || TYPE_REF_CAN_ALIAS_ALL (t)) | |
596 | return 0; | |
597 | ||
598 | return -1; | |
599 | } | |
600 | ||
601 | /* Return the alias set for the memory pointed to by T, which may be | |
602 | either a type or an expression. */ | |
603 | ||
604 | alias_set_type | |
605 | get_deref_alias_set (tree t) | |
606 | { | |
607 | alias_set_type set = get_deref_alias_set_1 (t); | |
608 | ||
609 | /* Fall back to the alias-set of the pointed-to type. */ | |
610 | if (set == -1) | |
611 | { | |
612 | if (! TYPE_P (t)) | |
613 | t = TREE_TYPE (t); | |
614 | set = get_alias_set (TREE_TYPE (t)); | |
615 | } | |
616 | ||
617 | return set; | |
618 | } | |
619 | ||
f7c44134 | 620 | /* Return the alias set for T, which may be either a type or an |
621 | expression. Call language-specific routine for help, if needed. */ | |
622 | ||
32c2fdea | 623 | alias_set_type |
aecda0d6 | 624 | get_alias_set (tree t) |
f7c44134 | 625 | { |
32c2fdea | 626 | alias_set_type set; |
f7c44134 | 627 | |
628 | /* If we're not doing any alias analysis, just assume everything | |
629 | aliases everything else. Also return 0 if this or its type is | |
630 | an error. */ | |
631 | if (! flag_strict_aliasing || t == error_mark_node | |
632 | || (! TYPE_P (t) | |
633 | && (TREE_TYPE (t) == 0 || TREE_TYPE (t) == error_mark_node))) | |
634 | return 0; | |
635 | ||
636 | /* We can be passed either an expression or a type. This and the | |
c3a9c149 | 637 | language-specific routine may make mutually-recursive calls to each other |
638 | to figure out what to do. At each juncture, we see if this is a tree | |
639 | that the language may need to handle specially. First handle things that | |
96216d37 | 640 | aren't types. */ |
1607663f | 641 | if (! TYPE_P (t)) |
f7c44134 | 642 | { |
96216d37 | 643 | tree inner = t; |
96216d37 | 644 | |
2a631e19 | 645 | /* Remove any nops, then give the language a chance to do |
646 | something with this tree before we look at it. */ | |
647 | STRIP_NOPS (t); | |
dc24ddbd | 648 | set = lang_hooks.get_alias_set (t); |
2a631e19 | 649 | if (set != -1) |
650 | return set; | |
651 | ||
96216d37 | 652 | /* First see if the actual object referenced is an INDIRECT_REF from a |
55f9d7dc | 653 | restrict-qualified pointer or a "void *". */ |
654 | while (handled_component_p (inner)) | |
96216d37 | 655 | { |
55f9d7dc | 656 | inner = TREE_OPERAND (inner, 0); |
2a631e19 | 657 | STRIP_NOPS (inner); |
96216d37 | 658 | } |
659 | ||
2a448a75 | 660 | if (INDIRECT_REF_P (inner)) |
96216d37 | 661 | { |
dd277d48 | 662 | set = get_deref_alias_set_1 (TREE_OPERAND (inner, 0)); |
663 | if (set != -1) | |
664 | return set; | |
96216d37 | 665 | } |
666 | ||
667 | /* Otherwise, pick up the outermost object that we could have a pointer | |
55f9d7dc | 668 | to, processing conversions as above. */ |
2b02580f | 669 | while (component_uses_parent_alias_set (t)) |
c3a9c149 | 670 | { |
55f9d7dc | 671 | t = TREE_OPERAND (t, 0); |
2a631e19 | 672 | STRIP_NOPS (t); |
673 | } | |
1607663f | 674 | |
96216d37 | 675 | /* If we've already determined the alias set for a decl, just return |
676 | it. This is necessary for C++ anonymous unions, whose component | |
677 | variables don't look like union members (boo!). */ | |
afce1f57 | 678 | if (TREE_CODE (t) == VAR_DECL |
e16ceb8e | 679 | && DECL_RTL_SET_P (t) && MEM_P (DECL_RTL (t))) |
afce1f57 | 680 | return MEM_ALIAS_SET (DECL_RTL (t)); |
681 | ||
1607663f | 682 | /* Now all we care about is the type. */ |
683 | t = TREE_TYPE (t); | |
f7c44134 | 684 | } |
685 | ||
f7c44134 | 686 | /* Variant qualifiers don't affect the alias set, so get the main |
dfe8e806 | 687 | variant. */ |
f7c44134 | 688 | t = TYPE_MAIN_VARIANT (t); |
dfe8e806 | 689 | |
690 | /* Always use the canonical type as well. If this is a type that | |
691 | requires structural comparisons to identify compatible types | |
692 | use alias set zero. */ | |
693 | if (TYPE_STRUCTURAL_EQUALITY_P (t)) | |
e58c17e7 | 694 | { |
695 | /* Allow the language to specify another alias set for this | |
696 | type. */ | |
697 | set = lang_hooks.get_alias_set (t); | |
698 | if (set != -1) | |
699 | return set; | |
700 | return 0; | |
701 | } | |
dfe8e806 | 702 | t = TYPE_CANONICAL (t); |
703 | /* Canonical types shouldn't form a tree nor should the canonical | |
704 | type require structural equality checks. */ | |
705 | gcc_assert (!TYPE_STRUCTURAL_EQUALITY_P (t) && TYPE_CANONICAL (t) == t); | |
706 | ||
707 | /* If this is a type with a known alias set, return it. */ | |
96216d37 | 708 | if (TYPE_ALIAS_SET_KNOWN_P (t)) |
f7c44134 | 709 | return TYPE_ALIAS_SET (t); |
710 | ||
b35a8f48 | 711 | /* We don't want to set TYPE_ALIAS_SET for incomplete types. */ |
712 | if (!COMPLETE_TYPE_P (t)) | |
713 | { | |
714 | /* For arrays with unknown size the conservative answer is the | |
715 | alias set of the element type. */ | |
716 | if (TREE_CODE (t) == ARRAY_TYPE) | |
717 | return get_alias_set (TREE_TYPE (t)); | |
718 | ||
719 | /* But return zero as a conservative answer for incomplete types. */ | |
720 | return 0; | |
721 | } | |
722 | ||
f7c44134 | 723 | /* See if the language has special handling for this type. */ |
dc24ddbd | 724 | set = lang_hooks.get_alias_set (t); |
2a631e19 | 725 | if (set != -1) |
96216d37 | 726 | return set; |
851dfbff | 727 | |
f7c44134 | 728 | /* There are no objects of FUNCTION_TYPE, so there's no point in |
729 | using up an alias set for them. (There are, of course, pointers | |
730 | and references to functions, but that's different.) */ | |
73bb980c | 731 | else if (TREE_CODE (t) == FUNCTION_TYPE |
732 | || TREE_CODE (t) == METHOD_TYPE) | |
f7c44134 | 733 | set = 0; |
9fcc3e54 | 734 | |
735 | /* Unless the language specifies otherwise, let vector types alias | |
736 | their components. This avoids some nasty type punning issues in | |
737 | normal usage. And indeed lets vectors be treated more like an | |
738 | array slice. */ | |
739 | else if (TREE_CODE (t) == VECTOR_TYPE) | |
740 | set = get_alias_set (TREE_TYPE (t)); | |
741 | ||
62d823d0 | 742 | /* Unless the language specifies otherwise, treat array types the |
743 | same as their components. This avoids the asymmetry we get | |
744 | through recording the components. Consider accessing a | |
745 | character(kind=1) through a reference to a character(kind=1)[1:1]. | |
746 | Or consider if we want to assign integer(kind=4)[0:D.1387] and | |
747 | integer(kind=4)[4] the same alias set or not. | |
748 | Just be pragmatic here and make sure the array and its element | |
749 | type get the same alias set assigned. */ | |
750 | else if (TREE_CODE (t) == ARRAY_TYPE | |
751 | && !TYPE_NONALIASED_COMPONENT (t)) | |
752 | set = get_alias_set (TREE_TYPE (t)); | |
753 | ||
f7c44134 | 754 | else |
755 | /* Otherwise make a new alias set for this type. */ | |
756 | set = new_alias_set (); | |
757 | ||
758 | TYPE_ALIAS_SET (t) = set; | |
851dfbff | 759 | |
760 | /* If this is an aggregate type, we must record any component aliasing | |
761 | information. */ | |
680210f2 | 762 | if (AGGREGATE_TYPE_P (t) || TREE_CODE (t) == COMPLEX_TYPE) |
851dfbff | 763 | record_component_aliases (t); |
764 | ||
f7c44134 | 765 | return set; |
766 | } | |
767 | ||
768 | /* Return a brand-new alias set. */ | |
769 | ||
32c2fdea | 770 | alias_set_type |
aecda0d6 | 771 | new_alias_set (void) |
f7c44134 | 772 | { |
f7c44134 | 773 | if (flag_strict_aliasing) |
56bbdce4 | 774 | { |
8b435339 | 775 | if (alias_sets == 0) |
776 | VEC_safe_push (alias_set_entry, gc, alias_sets, 0); | |
777 | VEC_safe_push (alias_set_entry, gc, alias_sets, 0); | |
778 | return VEC_length (alias_set_entry, alias_sets) - 1; | |
56bbdce4 | 779 | } |
f7c44134 | 780 | else |
781 | return 0; | |
782 | } | |
a5b1863e | 783 | |
8e2ef041 | 784 | /* Indicate that things in SUBSET can alias things in SUPERSET, but that |
785 | not everything that aliases SUPERSET also aliases SUBSET. For example, | |
786 | in C, a store to an `int' can alias a load of a structure containing an | |
787 | `int', and vice versa. But it can't alias a load of a 'double' member | |
788 | of the same structure. Here, the structure would be the SUPERSET and | |
789 | `int' the SUBSET. This relationship is also described in the comment at | |
790 | the beginning of this file. | |
791 | ||
792 | This function should be called only once per SUPERSET/SUBSET pair. | |
a5b1863e | 793 | |
794 | It is illegal for SUPERSET to be zero; everything is implicitly a | |
795 | subset of alias set zero. */ | |
796 | ||
892fdb03 | 797 | void |
32c2fdea | 798 | record_alias_subset (alias_set_type superset, alias_set_type subset) |
a5b1863e | 799 | { |
800 | alias_set_entry superset_entry; | |
801 | alias_set_entry subset_entry; | |
802 | ||
c3a9c149 | 803 | /* It is possible in complex type situations for both sets to be the same, |
804 | in which case we can ignore this operation. */ | |
805 | if (superset == subset) | |
806 | return; | |
807 | ||
64db345d | 808 | gcc_assert (superset); |
a5b1863e | 809 | |
810 | superset_entry = get_alias_set_entry (superset); | |
9342ee68 | 811 | if (superset_entry == 0) |
a5b1863e | 812 | { |
813 | /* Create an entry for the SUPERSET, so that we have a place to | |
814 | attach the SUBSET. */ | |
26dbec0a | 815 | superset_entry = GGC_NEW (struct alias_set_entry_d); |
a5b1863e | 816 | superset_entry->alias_set = superset; |
9342ee68 | 817 | superset_entry->children |
318dcdd8 | 818 | = splay_tree_new_ggc (splay_tree_compare_ints); |
f2e5de80 | 819 | superset_entry->has_zero_child = 0; |
8b435339 | 820 | VEC_replace (alias_set_entry, alias_sets, superset, superset_entry); |
a5b1863e | 821 | } |
822 | ||
851dfbff | 823 | if (subset == 0) |
824 | superset_entry->has_zero_child = 1; | |
825 | else | |
826 | { | |
827 | subset_entry = get_alias_set_entry (subset); | |
828 | /* If there is an entry for the subset, enter all of its children | |
829 | (if they are not already present) as children of the SUPERSET. */ | |
9342ee68 | 830 | if (subset_entry) |
851dfbff | 831 | { |
832 | if (subset_entry->has_zero_child) | |
833 | superset_entry->has_zero_child = 1; | |
083a2b5e | 834 | |
851dfbff | 835 | splay_tree_foreach (subset_entry->children, insert_subset_children, |
836 | superset_entry->children); | |
837 | } | |
a5b1863e | 838 | |
851dfbff | 839 | /* Enter the SUBSET itself as a child of the SUPERSET. */ |
9342ee68 | 840 | splay_tree_insert (superset_entry->children, |
851dfbff | 841 | (splay_tree_key) subset, 0); |
842 | } | |
a5b1863e | 843 | } |
844 | ||
9501a338 | 845 | /* Record that component types of TYPE, if any, are part of that type for |
846 | aliasing purposes. For record types, we only record component types | |
c67bf066 | 847 | for fields that are not marked non-addressable. For array types, we |
848 | only record the component type if it is not marked non-aliased. */ | |
9501a338 | 849 | |
850 | void | |
aecda0d6 | 851 | record_component_aliases (tree type) |
9501a338 | 852 | { |
32c2fdea | 853 | alias_set_type superset = get_alias_set (type); |
9501a338 | 854 | tree field; |
855 | ||
856 | if (superset == 0) | |
857 | return; | |
858 | ||
859 | switch (TREE_CODE (type)) | |
860 | { | |
9501a338 | 861 | case RECORD_TYPE: |
862 | case UNION_TYPE: | |
863 | case QUAL_UNION_TYPE: | |
8b332087 | 864 | /* Recursively record aliases for the base classes, if there are any. */ |
f6cc6a08 | 865 | if (TYPE_BINFO (type)) |
9342ee68 | 866 | { |
867 | int i; | |
f6cc6a08 | 868 | tree binfo, base_binfo; |
a0c938f0 | 869 | |
f6cc6a08 | 870 | for (binfo = TYPE_BINFO (type), i = 0; |
871 | BINFO_BASE_ITERATE (binfo, i, base_binfo); i++) | |
872 | record_alias_subset (superset, | |
873 | get_alias_set (BINFO_TYPE (base_binfo))); | |
9342ee68 | 874 | } |
9501a338 | 875 | for (field = TYPE_FIELDS (type); field != 0; field = TREE_CHAIN (field)) |
c67bf066 | 876 | if (TREE_CODE (field) == FIELD_DECL && !DECL_NONADDRESSABLE_P (field)) |
851dfbff | 877 | record_alias_subset (superset, get_alias_set (TREE_TYPE (field))); |
9501a338 | 878 | break; |
879 | ||
680210f2 | 880 | case COMPLEX_TYPE: |
881 | record_alias_subset (superset, get_alias_set (TREE_TYPE (type))); | |
882 | break; | |
883 | ||
62d823d0 | 884 | /* VECTOR_TYPE and ARRAY_TYPE share the alias set with their |
885 | element type. */ | |
886 | ||
9501a338 | 887 | default: |
888 | break; | |
889 | } | |
890 | } | |
891 | ||
f7c44134 | 892 | /* Allocate an alias set for use in storing and reading from the varargs |
893 | spill area. */ | |
894 | ||
32c2fdea | 895 | static GTY(()) alias_set_type varargs_set = -1; |
4ec9406e | 896 | |
32c2fdea | 897 | alias_set_type |
aecda0d6 | 898 | get_varargs_alias_set (void) |
f7c44134 | 899 | { |
fcdd3ab3 | 900 | #if 1 |
901 | /* We now lower VA_ARG_EXPR, and there's currently no way to attach the | |
902 | varargs alias set to an INDIRECT_REF (FIXME!), so we can't | |
903 | consistently use the varargs alias set for loads from the varargs | |
904 | area. So don't use it anywhere. */ | |
905 | return 0; | |
906 | #else | |
4ec9406e | 907 | if (varargs_set == -1) |
908 | varargs_set = new_alias_set (); | |
f7c44134 | 909 | |
4ec9406e | 910 | return varargs_set; |
fcdd3ab3 | 911 | #endif |
f7c44134 | 912 | } |
913 | ||
914 | /* Likewise, but used for the fixed portions of the frame, e.g., register | |
915 | save areas. */ | |
916 | ||
32c2fdea | 917 | static GTY(()) alias_set_type frame_set = -1; |
4ec9406e | 918 | |
32c2fdea | 919 | alias_set_type |
aecda0d6 | 920 | get_frame_alias_set (void) |
f7c44134 | 921 | { |
4ec9406e | 922 | if (frame_set == -1) |
923 | frame_set = new_alias_set (); | |
f7c44134 | 924 | |
4ec9406e | 925 | return frame_set; |
f7c44134 | 926 | } |
927 | ||
e7c893ba | 928 | /* Inside SRC, the source of a SET, find a base address. */ |
929 | ||
ea0cb7ae | 930 | static rtx |
aecda0d6 | 931 | find_base_value (rtx src) |
ea0cb7ae | 932 | { |
970c0c06 | 933 | unsigned int regno; |
d01410d3 | 934 | |
2e984a7a | 935 | #if defined (FIND_BASE_TERM) |
936 | /* Try machine-dependent ways to find the base term. */ | |
937 | src = FIND_BASE_TERM (src); | |
938 | #endif | |
939 | ||
ea0cb7ae | 940 | switch (GET_CODE (src)) |
941 | { | |
942 | case SYMBOL_REF: | |
943 | case LABEL_REF: | |
944 | return src; | |
945 | ||
946 | case REG: | |
9db10305 | 947 | regno = REGNO (src); |
083a2b5e | 948 | /* At the start of a function, argument registers have known base |
e7c893ba | 949 | values which may be lost later. Returning an ADDRESS |
950 | expression here allows optimization based on argument values | |
951 | even when the argument registers are used for other purposes. */ | |
970c0c06 | 952 | if (regno < FIRST_PSEUDO_REGISTER && copying_arguments) |
953 | return new_reg_base_value[regno]; | |
1a538f67 | 954 | |
ebd13eec | 955 | /* If a pseudo has a known base value, return it. Do not do this |
9464d436 | 956 | for non-fixed hard regs since it can result in a circular |
957 | dependency chain for registers which have values at function entry. | |
ebd13eec | 958 | |
959 | The test above is not sufficient because the scheduler may move | |
960 | a copy out of an arg reg past the NOTE_INSN_FUNCTION_BEGIN. */ | |
9464d436 | 961 | if ((regno >= FIRST_PSEUDO_REGISTER || fixed_regs[regno]) |
980f3285 | 962 | && regno < VEC_length (rtx, reg_base_value)) |
e5be0cc6 | 963 | { |
964 | /* If we're inside init_alias_analysis, use new_reg_base_value | |
965 | to reduce the number of relaxation iterations. */ | |
a303ed8c | 966 | if (new_reg_base_value && new_reg_base_value[regno] |
3072d30e | 967 | && DF_REG_DEF_COUNT (regno) == 1) |
e5be0cc6 | 968 | return new_reg_base_value[regno]; |
969 | ||
980f3285 | 970 | if (VEC_index (rtx, reg_base_value, regno)) |
971 | return VEC_index (rtx, reg_base_value, regno); | |
e5be0cc6 | 972 | } |
1a538f67 | 973 | |
1c5cb56c | 974 | return 0; |
ea0cb7ae | 975 | |
976 | case MEM: | |
977 | /* Check for an argument passed in memory. Only record in the | |
978 | copying-arguments block; it is too hard to track changes | |
979 | otherwise. */ | |
980 | if (copying_arguments | |
981 | && (XEXP (src, 0) == arg_pointer_rtx | |
982 | || (GET_CODE (XEXP (src, 0)) == PLUS | |
983 | && XEXP (XEXP (src, 0), 0) == arg_pointer_rtx))) | |
941522d6 | 984 | return gen_rtx_ADDRESS (VOIDmode, src); |
ea0cb7ae | 985 | return 0; |
986 | ||
987 | case CONST: | |
988 | src = XEXP (src, 0); | |
989 | if (GET_CODE (src) != PLUS && GET_CODE (src) != MINUS) | |
990 | break; | |
083a2b5e | 991 | |
2c0e001b | 992 | /* ... fall through ... */ |
e7c893ba | 993 | |
ea0cb7ae | 994 | case PLUS: |
995 | case MINUS: | |
e7c893ba | 996 | { |
06c5c535 | 997 | rtx temp, src_0 = XEXP (src, 0), src_1 = XEXP (src, 1); |
998 | ||
560de2f8 | 999 | /* If either operand is a REG that is a known pointer, then it |
1000 | is the base. */ | |
1001 | if (REG_P (src_0) && REG_POINTER (src_0)) | |
1002 | return find_base_value (src_0); | |
1003 | if (REG_P (src_1) && REG_POINTER (src_1)) | |
1004 | return find_base_value (src_1); | |
1005 | ||
06c5c535 | 1006 | /* If either operand is a REG, then see if we already have |
1007 | a known value for it. */ | |
560de2f8 | 1008 | if (REG_P (src_0)) |
06c5c535 | 1009 | { |
1010 | temp = find_base_value (src_0); | |
083a2b5e | 1011 | if (temp != 0) |
06c5c535 | 1012 | src_0 = temp; |
1013 | } | |
1014 | ||
560de2f8 | 1015 | if (REG_P (src_1)) |
06c5c535 | 1016 | { |
1017 | temp = find_base_value (src_1); | |
083a2b5e | 1018 | if (temp!= 0) |
06c5c535 | 1019 | src_1 = temp; |
1020 | } | |
e7c893ba | 1021 | |
560de2f8 | 1022 | /* If either base is named object or a special address |
1023 | (like an argument or stack reference), then use it for the | |
1024 | base term. */ | |
1025 | if (src_0 != 0 | |
1026 | && (GET_CODE (src_0) == SYMBOL_REF | |
1027 | || GET_CODE (src_0) == LABEL_REF | |
1028 | || (GET_CODE (src_0) == ADDRESS | |
1029 | && GET_MODE (src_0) != VOIDmode))) | |
1030 | return src_0; | |
1031 | ||
1032 | if (src_1 != 0 | |
1033 | && (GET_CODE (src_1) == SYMBOL_REF | |
1034 | || GET_CODE (src_1) == LABEL_REF | |
1035 | || (GET_CODE (src_1) == ADDRESS | |
1036 | && GET_MODE (src_1) != VOIDmode))) | |
1037 | return src_1; | |
1038 | ||
083a2b5e | 1039 | /* Guess which operand is the base address: |
06c5c535 | 1040 | If either operand is a symbol, then it is the base. If |
1041 | either operand is a CONST_INT, then the other is the base. */ | |
971ba038 | 1042 | if (CONST_INT_P (src_1) || CONSTANT_P (src_0)) |
e7c893ba | 1043 | return find_base_value (src_0); |
971ba038 | 1044 | else if (CONST_INT_P (src_0) || CONSTANT_P (src_1)) |
06c5c535 | 1045 | return find_base_value (src_1); |
1046 | ||
ea0cb7ae | 1047 | return 0; |
e7c893ba | 1048 | } |
1049 | ||
1050 | case LO_SUM: | |
1051 | /* The standard form is (lo_sum reg sym) so look only at the | |
1052 | second operand. */ | |
1053 | return find_base_value (XEXP (src, 1)); | |
ea0cb7ae | 1054 | |
1055 | case AND: | |
1056 | /* If the second operand is constant set the base | |
2c0e001b | 1057 | address to the first operand. */ |
971ba038 | 1058 | if (CONST_INT_P (XEXP (src, 1)) && INTVAL (XEXP (src, 1)) != 0) |
e7c893ba | 1059 | return find_base_value (XEXP (src, 0)); |
ea0cb7ae | 1060 | return 0; |
1061 | ||
43d45282 | 1062 | case TRUNCATE: |
98155838 | 1063 | /* As we do not know which address space the pointer is refering to, we can |
1064 | handle this only if the target does not support different pointer or | |
1065 | address modes depending on the address space. */ | |
1066 | if (!target_default_pointer_address_modes_p ()) | |
1067 | break; | |
43d45282 | 1068 | if (GET_MODE_SIZE (GET_MODE (src)) < GET_MODE_SIZE (Pmode)) |
1069 | break; | |
1070 | /* Fall through. */ | |
ea0cb7ae | 1071 | case HIGH: |
2be64ef0 | 1072 | case PRE_INC: |
1073 | case PRE_DEC: | |
1074 | case POST_INC: | |
1075 | case POST_DEC: | |
1076 | case PRE_MODIFY: | |
1077 | case POST_MODIFY: | |
e7c893ba | 1078 | return find_base_value (XEXP (src, 0)); |
99c14947 | 1079 | |
d01410d3 | 1080 | case ZERO_EXTEND: |
1081 | case SIGN_EXTEND: /* used for NT/Alpha pointers */ | |
98155838 | 1082 | /* As we do not know which address space the pointer is refering to, we can |
1083 | handle this only if the target does not support different pointer or | |
1084 | address modes depending on the address space. */ | |
1085 | if (!target_default_pointer_address_modes_p ()) | |
1086 | break; | |
1087 | ||
d01410d3 | 1088 | { |
1089 | rtx temp = find_base_value (XEXP (src, 0)); | |
1090 | ||
85d654dd | 1091 | if (temp != 0 && CONSTANT_P (temp)) |
d01410d3 | 1092 | temp = convert_memory_address (Pmode, temp); |
d01410d3 | 1093 | |
1094 | return temp; | |
1095 | } | |
1096 | ||
99c14947 | 1097 | default: |
1098 | break; | |
ea0cb7ae | 1099 | } |
1100 | ||
1101 | return 0; | |
1102 | } | |
1103 | ||
1104 | /* Called from init_alias_analysis indirectly through note_stores. */ | |
1105 | ||
083a2b5e | 1106 | /* While scanning insns to find base values, reg_seen[N] is nonzero if |
ea0cb7ae | 1107 | register N has been set in this function. */ |
1108 | static char *reg_seen; | |
1109 | ||
10882800 | 1110 | /* Addresses which are known not to alias anything else are identified |
1111 | by a unique integer. */ | |
06c5c535 | 1112 | static int unique_id; |
1113 | ||
e7c893ba | 1114 | static void |
81a410b1 | 1115 | record_set (rtx dest, const_rtx set, void *data ATTRIBUTE_UNUSED) |
ea0cb7ae | 1116 | { |
19cb6b50 | 1117 | unsigned regno; |
ea0cb7ae | 1118 | rtx src; |
3721f260 | 1119 | int n; |
ea0cb7ae | 1120 | |
8ad4c111 | 1121 | if (!REG_P (dest)) |
ea0cb7ae | 1122 | return; |
1123 | ||
9db10305 | 1124 | regno = REGNO (dest); |
ea0cb7ae | 1125 | |
980f3285 | 1126 | gcc_assert (regno < VEC_length (rtx, reg_base_value)); |
c2e94b25 | 1127 | |
3721f260 | 1128 | /* If this spans multiple hard registers, then we must indicate that every |
1129 | register has an unusable value. */ | |
1130 | if (regno < FIRST_PSEUDO_REGISTER) | |
67d6c12b | 1131 | n = hard_regno_nregs[regno][GET_MODE (dest)]; |
3721f260 | 1132 | else |
1133 | n = 1; | |
1134 | if (n != 1) | |
1135 | { | |
1136 | while (--n >= 0) | |
1137 | { | |
1138 | reg_seen[regno + n] = 1; | |
1139 | new_reg_base_value[regno + n] = 0; | |
1140 | } | |
1141 | return; | |
1142 | } | |
1143 | ||
ea0cb7ae | 1144 | if (set) |
1145 | { | |
1146 | /* A CLOBBER wipes out any old value but does not prevent a previously | |
1147 | unset register from acquiring a base address (i.e. reg_seen is not | |
1148 | set). */ | |
1149 | if (GET_CODE (set) == CLOBBER) | |
1150 | { | |
06c5c535 | 1151 | new_reg_base_value[regno] = 0; |
ea0cb7ae | 1152 | return; |
1153 | } | |
1154 | src = SET_SRC (set); | |
1155 | } | |
1156 | else | |
1157 | { | |
ea0cb7ae | 1158 | if (reg_seen[regno]) |
1159 | { | |
06c5c535 | 1160 | new_reg_base_value[regno] = 0; |
ea0cb7ae | 1161 | return; |
1162 | } | |
1163 | reg_seen[regno] = 1; | |
941522d6 | 1164 | new_reg_base_value[regno] = gen_rtx_ADDRESS (Pmode, |
1165 | GEN_INT (unique_id++)); | |
ea0cb7ae | 1166 | return; |
1167 | } | |
1168 | ||
ad6b1fe1 | 1169 | /* If this is not the first set of REGNO, see whether the new value |
1170 | is related to the old one. There are two cases of interest: | |
1171 | ||
1172 | (1) The register might be assigned an entirely new value | |
1173 | that has the same base term as the original set. | |
1174 | ||
1175 | (2) The set might be a simple self-modification that | |
1176 | cannot change REGNO's base value. | |
1177 | ||
1178 | If neither case holds, reject the original base value as invalid. | |
1179 | Note that the following situation is not detected: | |
1180 | ||
a0c938f0 | 1181 | extern int x, y; int *p = &x; p += (&y-&x); |
ad6b1fe1 | 1182 | |
ea0cb7ae | 1183 | ANSI C does not allow computing the difference of addresses |
1184 | of distinct top level objects. */ | |
ad6b1fe1 | 1185 | if (new_reg_base_value[regno] != 0 |
1186 | && find_base_value (src) != new_reg_base_value[regno]) | |
ea0cb7ae | 1187 | switch (GET_CODE (src)) |
1188 | { | |
e7c893ba | 1189 | case LO_SUM: |
ea0cb7ae | 1190 | case MINUS: |
1191 | if (XEXP (src, 0) != dest && XEXP (src, 1) != dest) | |
06c5c535 | 1192 | new_reg_base_value[regno] = 0; |
ea0cb7ae | 1193 | break; |
43d45282 | 1194 | case PLUS: |
1195 | /* If the value we add in the PLUS is also a valid base value, | |
1196 | this might be the actual base value, and the original value | |
1197 | an index. */ | |
1198 | { | |
1199 | rtx other = NULL_RTX; | |
1200 | ||
1201 | if (XEXP (src, 0) == dest) | |
1202 | other = XEXP (src, 1); | |
1203 | else if (XEXP (src, 1) == dest) | |
1204 | other = XEXP (src, 0); | |
1205 | ||
1206 | if (! other || find_base_value (other)) | |
1207 | new_reg_base_value[regno] = 0; | |
1208 | break; | |
1209 | } | |
ea0cb7ae | 1210 | case AND: |
971ba038 | 1211 | if (XEXP (src, 0) != dest || !CONST_INT_P (XEXP (src, 1))) |
06c5c535 | 1212 | new_reg_base_value[regno] = 0; |
ea0cb7ae | 1213 | break; |
ea0cb7ae | 1214 | default: |
06c5c535 | 1215 | new_reg_base_value[regno] = 0; |
ea0cb7ae | 1216 | break; |
1217 | } | |
1218 | /* If this is the first set of a register, record the value. */ | |
1219 | else if ((regno >= FIRST_PSEUDO_REGISTER || ! fixed_regs[regno]) | |
06c5c535 | 1220 | && ! reg_seen[regno] && new_reg_base_value[regno] == 0) |
1221 | new_reg_base_value[regno] = find_base_value (src); | |
ea0cb7ae | 1222 | |
1223 | reg_seen[regno] = 1; | |
1224 | } | |
1225 | ||
12cb06ad | 1226 | /* If a value is known for REGNO, return it. */ |
1227 | ||
a0c938f0 | 1228 | rtx |
12cb06ad | 1229 | get_reg_known_value (unsigned int regno) |
1230 | { | |
1231 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1232 | { | |
1233 | regno -= FIRST_PSEUDO_REGISTER; | |
1234 | if (regno < reg_known_value_size) | |
1235 | return reg_known_value[regno]; | |
1236 | } | |
1237 | return NULL; | |
9f5e1a5a | 1238 | } |
1239 | ||
12cb06ad | 1240 | /* Set it. */ |
1241 | ||
1242 | static void | |
1243 | set_reg_known_value (unsigned int regno, rtx val) | |
1244 | { | |
1245 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1246 | { | |
1247 | regno -= FIRST_PSEUDO_REGISTER; | |
1248 | if (regno < reg_known_value_size) | |
1249 | reg_known_value[regno] = val; | |
1250 | } | |
1251 | } | |
1252 | ||
1253 | /* Similarly for reg_known_equiv_p. */ | |
1254 | ||
1255 | bool | |
1256 | get_reg_known_equiv_p (unsigned int regno) | |
1257 | { | |
1258 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1259 | { | |
1260 | regno -= FIRST_PSEUDO_REGISTER; | |
1261 | if (regno < reg_known_value_size) | |
1262 | return reg_known_equiv_p[regno]; | |
1263 | } | |
1264 | return false; | |
1265 | } | |
1266 | ||
1267 | static void | |
1268 | set_reg_known_equiv_p (unsigned int regno, bool val) | |
1269 | { | |
1270 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1271 | { | |
1272 | regno -= FIRST_PSEUDO_REGISTER; | |
1273 | if (regno < reg_known_value_size) | |
1274 | reg_known_equiv_p[regno] = val; | |
1275 | } | |
1276 | } | |
1277 | ||
1278 | ||
7cfb9bcf | 1279 | /* Returns a canonical version of X, from the point of view alias |
1280 | analysis. (For example, if X is a MEM whose address is a register, | |
1281 | and the register has a known value (say a SYMBOL_REF), then a MEM | |
1282 | whose address is the SYMBOL_REF is returned.) */ | |
1283 | ||
1284 | rtx | |
aecda0d6 | 1285 | canon_rtx (rtx x) |
ea0cb7ae | 1286 | { |
1287 | /* Recursively look for equivalences. */ | |
8ad4c111 | 1288 | if (REG_P (x) && REGNO (x) >= FIRST_PSEUDO_REGISTER) |
12cb06ad | 1289 | { |
1290 | rtx t = get_reg_known_value (REGNO (x)); | |
1291 | if (t == x) | |
1292 | return x; | |
1293 | if (t) | |
1294 | return canon_rtx (t); | |
1295 | } | |
1296 | ||
1297 | if (GET_CODE (x) == PLUS) | |
ea0cb7ae | 1298 | { |
1299 | rtx x0 = canon_rtx (XEXP (x, 0)); | |
1300 | rtx x1 = canon_rtx (XEXP (x, 1)); | |
1301 | ||
1302 | if (x0 != XEXP (x, 0) || x1 != XEXP (x, 1)) | |
1303 | { | |
971ba038 | 1304 | if (CONST_INT_P (x0)) |
b244d4c7 | 1305 | return plus_constant (x1, INTVAL (x0)); |
971ba038 | 1306 | else if (CONST_INT_P (x1)) |
b244d4c7 | 1307 | return plus_constant (x0, INTVAL (x1)); |
941522d6 | 1308 | return gen_rtx_PLUS (GET_MODE (x), x0, x1); |
ea0cb7ae | 1309 | } |
1310 | } | |
083a2b5e | 1311 | |
ea0cb7ae | 1312 | /* This gives us much better alias analysis when called from |
1313 | the loop optimizer. Note we want to leave the original | |
1314 | MEM alone, but need to return the canonicalized MEM with | |
1315 | all the flags with their original values. */ | |
e16ceb8e | 1316 | else if (MEM_P (x)) |
e4e86ec5 | 1317 | x = replace_equiv_address_nv (x, canon_rtx (XEXP (x, 0))); |
083a2b5e | 1318 | |
ea0cb7ae | 1319 | return x; |
1320 | } | |
1321 | ||
1322 | /* Return 1 if X and Y are identical-looking rtx's. | |
6285298a | 1323 | Expect that X and Y has been already canonicalized. |
ea0cb7ae | 1324 | |
1325 | We use the data in reg_known_value above to see if two registers with | |
1326 | different numbers are, in fact, equivalent. */ | |
1327 | ||
1328 | static int | |
7ecb5bb2 | 1329 | rtx_equal_for_memref_p (const_rtx x, const_rtx y) |
ea0cb7ae | 1330 | { |
19cb6b50 | 1331 | int i; |
1332 | int j; | |
1333 | enum rtx_code code; | |
1334 | const char *fmt; | |
ea0cb7ae | 1335 | |
1336 | if (x == 0 && y == 0) | |
1337 | return 1; | |
1338 | if (x == 0 || y == 0) | |
1339 | return 0; | |
083a2b5e | 1340 | |
ea0cb7ae | 1341 | if (x == y) |
1342 | return 1; | |
1343 | ||
1344 | code = GET_CODE (x); | |
1345 | /* Rtx's of different codes cannot be equal. */ | |
1346 | if (code != GET_CODE (y)) | |
1347 | return 0; | |
1348 | ||
1349 | /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. | |
1350 | (REG:SI x) and (REG:HI x) are NOT equivalent. */ | |
1351 | ||
1352 | if (GET_MODE (x) != GET_MODE (y)) | |
1353 | return 0; | |
1354 | ||
7cfb9bcf | 1355 | /* Some RTL can be compared without a recursive examination. */ |
1356 | switch (code) | |
1357 | { | |
1358 | case REG: | |
1359 | return REGNO (x) == REGNO (y); | |
1360 | ||
1361 | case LABEL_REF: | |
1362 | return XEXP (x, 0) == XEXP (y, 0); | |
9342ee68 | 1363 | |
7cfb9bcf | 1364 | case SYMBOL_REF: |
1365 | return XSTR (x, 0) == XSTR (y, 0); | |
1366 | ||
a2e238f7 | 1367 | case VALUE: |
7cfb9bcf | 1368 | case CONST_INT: |
1369 | case CONST_DOUBLE: | |
e397ad8e | 1370 | case CONST_FIXED: |
7cfb9bcf | 1371 | /* There's no need to compare the contents of CONST_DOUBLEs or |
1372 | CONST_INTs because pointer equality is a good enough | |
1373 | comparison for these nodes. */ | |
1374 | return 0; | |
1375 | ||
7cfb9bcf | 1376 | default: |
1377 | break; | |
1378 | } | |
ea0cb7ae | 1379 | |
6285298a | 1380 | /* canon_rtx knows how to handle plus. No need to canonicalize. */ |
1381 | if (code == PLUS) | |
ea0cb7ae | 1382 | return ((rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 0)) |
1383 | && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 1))) | |
1384 | || (rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 1)) | |
1385 | && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 0)))); | |
6285298a | 1386 | /* For commutative operations, the RTX match if the operand match in any |
1387 | order. Also handle the simple binary and unary cases without a loop. */ | |
6720e96c | 1388 | if (COMMUTATIVE_P (x)) |
6285298a | 1389 | { |
1390 | rtx xop0 = canon_rtx (XEXP (x, 0)); | |
1391 | rtx yop0 = canon_rtx (XEXP (y, 0)); | |
1392 | rtx yop1 = canon_rtx (XEXP (y, 1)); | |
1393 | ||
1394 | return ((rtx_equal_for_memref_p (xop0, yop0) | |
1395 | && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), yop1)) | |
1396 | || (rtx_equal_for_memref_p (xop0, yop1) | |
1397 | && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), yop0))); | |
1398 | } | |
6720e96c | 1399 | else if (NON_COMMUTATIVE_P (x)) |
6285298a | 1400 | { |
1401 | return (rtx_equal_for_memref_p (canon_rtx (XEXP (x, 0)), | |
aecda0d6 | 1402 | canon_rtx (XEXP (y, 0))) |
6285298a | 1403 | && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), |
1404 | canon_rtx (XEXP (y, 1)))); | |
1405 | } | |
6720e96c | 1406 | else if (UNARY_P (x)) |
6285298a | 1407 | return rtx_equal_for_memref_p (canon_rtx (XEXP (x, 0)), |
aecda0d6 | 1408 | canon_rtx (XEXP (y, 0))); |
ea0cb7ae | 1409 | |
1410 | /* Compare the elements. If any pair of corresponding elements | |
1a6c3add | 1411 | fail to match, return 0 for the whole things. |
1412 | ||
1413 | Limit cases to types which actually appear in addresses. */ | |
ea0cb7ae | 1414 | |
1415 | fmt = GET_RTX_FORMAT (code); | |
1416 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
1417 | { | |
1418 | switch (fmt[i]) | |
1419 | { | |
ea0cb7ae | 1420 | case 'i': |
1421 | if (XINT (x, i) != XINT (y, i)) | |
1422 | return 0; | |
1423 | break; | |
1424 | ||
ea0cb7ae | 1425 | case 'E': |
1426 | /* Two vectors must have the same length. */ | |
1427 | if (XVECLEN (x, i) != XVECLEN (y, i)) | |
1428 | return 0; | |
1429 | ||
1430 | /* And the corresponding elements must match. */ | |
1431 | for (j = 0; j < XVECLEN (x, i); j++) | |
6285298a | 1432 | if (rtx_equal_for_memref_p (canon_rtx (XVECEXP (x, i, j)), |
1433 | canon_rtx (XVECEXP (y, i, j))) == 0) | |
ea0cb7ae | 1434 | return 0; |
1435 | break; | |
1436 | ||
1437 | case 'e': | |
6285298a | 1438 | if (rtx_equal_for_memref_p (canon_rtx (XEXP (x, i)), |
1439 | canon_rtx (XEXP (y, i))) == 0) | |
ea0cb7ae | 1440 | return 0; |
1441 | break; | |
1442 | ||
83ec925c | 1443 | /* This can happen for asm operands. */ |
1444 | case 's': | |
1445 | if (strcmp (XSTR (x, i), XSTR (y, i))) | |
1446 | return 0; | |
1447 | break; | |
1448 | ||
23c04f6b | 1449 | /* This can happen for an asm which clobbers memory. */ |
1450 | case '0': | |
1451 | break; | |
1452 | ||
ea0cb7ae | 1453 | /* It is believed that rtx's at this level will never |
1454 | contain anything but integers and other rtx's, | |
1455 | except for within LABEL_REFs and SYMBOL_REFs. */ | |
1456 | default: | |
64db345d | 1457 | gcc_unreachable (); |
ea0cb7ae | 1458 | } |
1459 | } | |
1460 | return 1; | |
1461 | } | |
1462 | ||
5a37abfd | 1463 | rtx |
aecda0d6 | 1464 | find_base_term (rtx x) |
ea0cb7ae | 1465 | { |
1617c276 | 1466 | cselib_val *val; |
1467 | struct elt_loc_list *l; | |
1468 | ||
15750b1e | 1469 | #if defined (FIND_BASE_TERM) |
1470 | /* Try machine-dependent ways to find the base term. */ | |
1471 | x = FIND_BASE_TERM (x); | |
1472 | #endif | |
1473 | ||
ea0cb7ae | 1474 | switch (GET_CODE (x)) |
1475 | { | |
1476 | case REG: | |
1477 | return REG_BASE_VALUE (x); | |
1478 | ||
2be64ef0 | 1479 | case TRUNCATE: |
98155838 | 1480 | /* As we do not know which address space the pointer is refering to, we can |
1481 | handle this only if the target does not support different pointer or | |
1482 | address modes depending on the address space. */ | |
1483 | if (!target_default_pointer_address_modes_p ()) | |
1484 | return 0; | |
2be64ef0 | 1485 | if (GET_MODE_SIZE (GET_MODE (x)) < GET_MODE_SIZE (Pmode)) |
9342ee68 | 1486 | return 0; |
2be64ef0 | 1487 | /* Fall through. */ |
ea0cb7ae | 1488 | case HIGH: |
22dfec7d | 1489 | case PRE_INC: |
1490 | case PRE_DEC: | |
1491 | case POST_INC: | |
1492 | case POST_DEC: | |
2be64ef0 | 1493 | case PRE_MODIFY: |
1494 | case POST_MODIFY: | |
22dfec7d | 1495 | return find_base_term (XEXP (x, 0)); |
1496 | ||
5104ef69 | 1497 | case ZERO_EXTEND: |
1498 | case SIGN_EXTEND: /* Used for Alpha/NT pointers */ | |
98155838 | 1499 | /* As we do not know which address space the pointer is refering to, we can |
1500 | handle this only if the target does not support different pointer or | |
1501 | address modes depending on the address space. */ | |
1502 | if (!target_default_pointer_address_modes_p ()) | |
1503 | return 0; | |
1504 | ||
5104ef69 | 1505 | { |
1506 | rtx temp = find_base_term (XEXP (x, 0)); | |
1507 | ||
85d654dd | 1508 | if (temp != 0 && CONSTANT_P (temp)) |
5104ef69 | 1509 | temp = convert_memory_address (Pmode, temp); |
5104ef69 | 1510 | |
1511 | return temp; | |
1512 | } | |
1513 | ||
1617c276 | 1514 | case VALUE: |
1515 | val = CSELIB_VAL_PTR (x); | |
a2e238f7 | 1516 | if (!val) |
1517 | return 0; | |
1617c276 | 1518 | for (l = val->locs; l; l = l->next) |
1519 | if ((x = find_base_term (l->loc)) != 0) | |
1520 | return x; | |
1521 | return 0; | |
1522 | ||
a7cf5bbf | 1523 | case LO_SUM: |
1524 | /* The standard form is (lo_sum reg sym) so look only at the | |
1525 | second operand. */ | |
1526 | return find_base_term (XEXP (x, 1)); | |
1527 | ||
ea0cb7ae | 1528 | case CONST: |
1529 | x = XEXP (x, 0); | |
1530 | if (GET_CODE (x) != PLUS && GET_CODE (x) != MINUS) | |
1531 | return 0; | |
b4b174c3 | 1532 | /* Fall through. */ |
ea0cb7ae | 1533 | case PLUS: |
1534 | case MINUS: | |
1535 | { | |
1b5bbc4c | 1536 | rtx tmp1 = XEXP (x, 0); |
1537 | rtx tmp2 = XEXP (x, 1); | |
1538 | ||
35a3065a | 1539 | /* This is a little bit tricky since we have to determine which of |
1b5bbc4c | 1540 | the two operands represents the real base address. Otherwise this |
1541 | routine may return the index register instead of the base register. | |
1542 | ||
1543 | That may cause us to believe no aliasing was possible, when in | |
1544 | fact aliasing is possible. | |
1545 | ||
1546 | We use a few simple tests to guess the base register. Additional | |
1547 | tests can certainly be added. For example, if one of the operands | |
1548 | is a shift or multiply, then it must be the index register and the | |
1549 | other operand is the base register. */ | |
9342ee68 | 1550 | |
15750b1e | 1551 | if (tmp1 == pic_offset_table_rtx && CONSTANT_P (tmp2)) |
1552 | return find_base_term (tmp2); | |
1553 | ||
1b5bbc4c | 1554 | /* If either operand is known to be a pointer, then use it |
1555 | to determine the base term. */ | |
e61a0a7f | 1556 | if (REG_P (tmp1) && REG_POINTER (tmp1)) |
02b0d167 | 1557 | { |
1558 | rtx base = find_base_term (tmp1); | |
1559 | if (base) | |
1560 | return base; | |
1561 | } | |
1b5bbc4c | 1562 | |
e61a0a7f | 1563 | if (REG_P (tmp2) && REG_POINTER (tmp2)) |
02b0d167 | 1564 | { |
1565 | rtx base = find_base_term (tmp2); | |
1566 | if (base) | |
1567 | return base; | |
1568 | } | |
1b5bbc4c | 1569 | |
1570 | /* Neither operand was known to be a pointer. Go ahead and find the | |
1571 | base term for both operands. */ | |
1572 | tmp1 = find_base_term (tmp1); | |
1573 | tmp2 = find_base_term (tmp2); | |
1574 | ||
1575 | /* If either base term is named object or a special address | |
1576 | (like an argument or stack reference), then use it for the | |
1577 | base term. */ | |
083a2b5e | 1578 | if (tmp1 != 0 |
1b5bbc4c | 1579 | && (GET_CODE (tmp1) == SYMBOL_REF |
1580 | || GET_CODE (tmp1) == LABEL_REF | |
1581 | || (GET_CODE (tmp1) == ADDRESS | |
1582 | && GET_MODE (tmp1) != VOIDmode))) | |
1583 | return tmp1; | |
1584 | ||
083a2b5e | 1585 | if (tmp2 != 0 |
1b5bbc4c | 1586 | && (GET_CODE (tmp2) == SYMBOL_REF |
1587 | || GET_CODE (tmp2) == LABEL_REF | |
1588 | || (GET_CODE (tmp2) == ADDRESS | |
1589 | && GET_MODE (tmp2) != VOIDmode))) | |
1590 | return tmp2; | |
1591 | ||
1592 | /* We could not determine which of the two operands was the | |
1593 | base register and which was the index. So we can determine | |
1594 | nothing from the base alias check. */ | |
1595 | return 0; | |
ea0cb7ae | 1596 | } |
1597 | ||
1598 | case AND: | |
971ba038 | 1599 | if (CONST_INT_P (XEXP (x, 1)) && INTVAL (XEXP (x, 1)) != 0) |
2be64ef0 | 1600 | return find_base_term (XEXP (x, 0)); |
ea0cb7ae | 1601 | return 0; |
1602 | ||
1603 | case SYMBOL_REF: | |
1604 | case LABEL_REF: | |
1605 | return x; | |
1606 | ||
1607 | default: | |
1608 | return 0; | |
1609 | } | |
1610 | } | |
1611 | ||
1612 | /* Return 0 if the addresses X and Y are known to point to different | |
1613 | objects, 1 if they might be pointers to the same object. */ | |
1614 | ||
1615 | static int | |
aecda0d6 | 1616 | base_alias_check (rtx x, rtx y, enum machine_mode x_mode, |
1617 | enum machine_mode y_mode) | |
ea0cb7ae | 1618 | { |
1619 | rtx x_base = find_base_term (x); | |
1620 | rtx y_base = find_base_term (y); | |
1621 | ||
3ad3a0ed | 1622 | /* If the address itself has no known base see if a known equivalent |
1623 | value has one. If either address still has no known base, nothing | |
1624 | is known about aliasing. */ | |
1625 | if (x_base == 0) | |
1626 | { | |
1627 | rtx x_c; | |
083a2b5e | 1628 | |
3ad3a0ed | 1629 | if (! flag_expensive_optimizations || (x_c = canon_rtx (x)) == x) |
1630 | return 1; | |
083a2b5e | 1631 | |
3ad3a0ed | 1632 | x_base = find_base_term (x_c); |
1633 | if (x_base == 0) | |
1634 | return 1; | |
1635 | } | |
ea0cb7ae | 1636 | |
3ad3a0ed | 1637 | if (y_base == 0) |
1638 | { | |
1639 | rtx y_c; | |
1640 | if (! flag_expensive_optimizations || (y_c = canon_rtx (y)) == y) | |
1641 | return 1; | |
083a2b5e | 1642 | |
3ad3a0ed | 1643 | y_base = find_base_term (y_c); |
1644 | if (y_base == 0) | |
1645 | return 1; | |
1646 | } | |
1647 | ||
1648 | /* If the base addresses are equal nothing is known about aliasing. */ | |
1649 | if (rtx_equal_p (x_base, y_base)) | |
ea0cb7ae | 1650 | return 1; |
1651 | ||
f92492f7 | 1652 | /* The base addresses are different expressions. If they are not accessed |
1653 | via AND, there is no conflict. We can bring knowledge of object | |
1654 | alignment into play here. For example, on alpha, "char a, b;" can | |
1655 | alias one another, though "char a; long b;" cannot. AND addesses may | |
1656 | implicitly alias surrounding objects; i.e. unaligned access in DImode | |
1657 | via AND address can alias all surrounding object types except those | |
1658 | with aligment 8 or higher. */ | |
1659 | if (GET_CODE (x) == AND && GET_CODE (y) == AND) | |
1660 | return 1; | |
1661 | if (GET_CODE (x) == AND | |
971ba038 | 1662 | && (!CONST_INT_P (XEXP (x, 1)) |
f92492f7 | 1663 | || (int) GET_MODE_UNIT_SIZE (y_mode) < -INTVAL (XEXP (x, 1)))) |
1664 | return 1; | |
1665 | if (GET_CODE (y) == AND | |
971ba038 | 1666 | && (!CONST_INT_P (XEXP (y, 1)) |
f92492f7 | 1667 | || (int) GET_MODE_UNIT_SIZE (x_mode) < -INTVAL (XEXP (y, 1)))) |
1668 | return 1; | |
1669 | ||
1670 | /* Differing symbols not accessed via AND never alias. */ | |
ea0cb7ae | 1671 | if (GET_CODE (x_base) != ADDRESS && GET_CODE (y_base) != ADDRESS) |
f92492f7 | 1672 | return 0; |
ea0cb7ae | 1673 | |
1674 | /* If one address is a stack reference there can be no alias: | |
1675 | stack references using different base registers do not alias, | |
1676 | a stack reference can not alias a parameter, and a stack reference | |
1677 | can not alias a global. */ | |
1678 | if ((GET_CODE (x_base) == ADDRESS && GET_MODE (x_base) == Pmode) | |
1679 | || (GET_CODE (y_base) == ADDRESS && GET_MODE (y_base) == Pmode)) | |
1680 | return 0; | |
1681 | ||
1682 | if (! flag_argument_noalias) | |
1683 | return 1; | |
1684 | ||
1685 | if (flag_argument_noalias > 1) | |
1686 | return 0; | |
1687 | ||
2c0e001b | 1688 | /* Weak noalias assertion (arguments are distinct, but may match globals). */ |
ea0cb7ae | 1689 | return ! (GET_MODE (x_base) == VOIDmode && GET_MODE (y_base) == VOIDmode); |
1690 | } | |
1691 | ||
1617c276 | 1692 | /* Convert the address X into something we can use. This is done by returning |
1693 | it unchanged unless it is a value; in the latter case we call cselib to get | |
1694 | a more useful rtx. */ | |
f7c44134 | 1695 | |
8e802be9 | 1696 | rtx |
aecda0d6 | 1697 | get_addr (rtx x) |
1617c276 | 1698 | { |
1699 | cselib_val *v; | |
1700 | struct elt_loc_list *l; | |
1701 | ||
1702 | if (GET_CODE (x) != VALUE) | |
1703 | return x; | |
1704 | v = CSELIB_VAL_PTR (x); | |
a2e238f7 | 1705 | if (v) |
1706 | { | |
1707 | for (l = v->locs; l; l = l->next) | |
1708 | if (CONSTANT_P (l->loc)) | |
1709 | return l->loc; | |
1710 | for (l = v->locs; l; l = l->next) | |
e16ceb8e | 1711 | if (!REG_P (l->loc) && !MEM_P (l->loc)) |
a2e238f7 | 1712 | return l->loc; |
1713 | if (v->locs) | |
1714 | return v->locs->loc; | |
1715 | } | |
1617c276 | 1716 | return x; |
1717 | } | |
1718 | ||
b9f92976 | 1719 | /* Return the address of the (N_REFS + 1)th memory reference to ADDR |
1720 | where SIZE is the size in bytes of the memory reference. If ADDR | |
1721 | is not modified by the memory reference then ADDR is returned. */ | |
1722 | ||
0aa9ffd4 | 1723 | static rtx |
aecda0d6 | 1724 | addr_side_effect_eval (rtx addr, int size, int n_refs) |
b9f92976 | 1725 | { |
1726 | int offset = 0; | |
9342ee68 | 1727 | |
b9f92976 | 1728 | switch (GET_CODE (addr)) |
1729 | { | |
1730 | case PRE_INC: | |
1731 | offset = (n_refs + 1) * size; | |
1732 | break; | |
1733 | case PRE_DEC: | |
1734 | offset = -(n_refs + 1) * size; | |
1735 | break; | |
1736 | case POST_INC: | |
1737 | offset = n_refs * size; | |
1738 | break; | |
1739 | case POST_DEC: | |
1740 | offset = -n_refs * size; | |
1741 | break; | |
1742 | ||
1743 | default: | |
1744 | return addr; | |
1745 | } | |
9342ee68 | 1746 | |
b9f92976 | 1747 | if (offset) |
6285298a | 1748 | addr = gen_rtx_PLUS (GET_MODE (addr), XEXP (addr, 0), |
a0c938f0 | 1749 | GEN_INT (offset)); |
b9f92976 | 1750 | else |
1751 | addr = XEXP (addr, 0); | |
6285298a | 1752 | addr = canon_rtx (addr); |
b9f92976 | 1753 | |
1754 | return addr; | |
1755 | } | |
1756 | ||
ea0cb7ae | 1757 | /* Return nonzero if X and Y (memory addresses) could reference the |
1758 | same location in memory. C is an offset accumulator. When | |
1759 | C is nonzero, we are testing aliases between X and Y + C. | |
1760 | XSIZE is the size in bytes of the X reference, | |
1761 | similarly YSIZE is the size in bytes for Y. | |
6285298a | 1762 | Expect that canon_rtx has been already called for X and Y. |
ea0cb7ae | 1763 | |
1764 | If XSIZE or YSIZE is zero, we do not know the amount of memory being | |
1765 | referenced (the reference was BLKmode), so make the most pessimistic | |
1766 | assumptions. | |
1767 | ||
1e38bf49 | 1768 | If XSIZE or YSIZE is negative, we may access memory outside the object |
1769 | being referenced as a side effect. This can happen when using AND to | |
1770 | align memory references, as is done on the Alpha. | |
1771 | ||
ea0cb7ae | 1772 | Nice to notice that varying addresses cannot conflict with fp if no |
4958fe6e | 1773 | local variables had their addresses taken, but that's too hard now. */ |
ea0cb7ae | 1774 | |
ea0cb7ae | 1775 | static int |
aecda0d6 | 1776 | memrefs_conflict_p (int xsize, rtx x, int ysize, rtx y, HOST_WIDE_INT c) |
ea0cb7ae | 1777 | { |
1617c276 | 1778 | if (GET_CODE (x) == VALUE) |
1779 | x = get_addr (x); | |
1780 | if (GET_CODE (y) == VALUE) | |
1781 | y = get_addr (y); | |
ea0cb7ae | 1782 | if (GET_CODE (x) == HIGH) |
1783 | x = XEXP (x, 0); | |
1784 | else if (GET_CODE (x) == LO_SUM) | |
1785 | x = XEXP (x, 1); | |
1786 | else | |
6285298a | 1787 | x = addr_side_effect_eval (x, xsize, 0); |
ea0cb7ae | 1788 | if (GET_CODE (y) == HIGH) |
1789 | y = XEXP (y, 0); | |
1790 | else if (GET_CODE (y) == LO_SUM) | |
1791 | y = XEXP (y, 1); | |
1792 | else | |
6285298a | 1793 | y = addr_side_effect_eval (y, ysize, 0); |
ea0cb7ae | 1794 | |
1795 | if (rtx_equal_for_memref_p (x, y)) | |
1796 | { | |
1e38bf49 | 1797 | if (xsize <= 0 || ysize <= 0) |
ea0cb7ae | 1798 | return 1; |
1799 | if (c >= 0 && xsize > c) | |
1800 | return 1; | |
1801 | if (c < 0 && ysize+c > 0) | |
1802 | return 1; | |
1803 | return 0; | |
1804 | } | |
1805 | ||
35d3eedd | 1806 | /* This code used to check for conflicts involving stack references and |
1807 | globals but the base address alias code now handles these cases. */ | |
ea0cb7ae | 1808 | |
1809 | if (GET_CODE (x) == PLUS) | |
1810 | { | |
1811 | /* The fact that X is canonicalized means that this | |
1812 | PLUS rtx is canonicalized. */ | |
1813 | rtx x0 = XEXP (x, 0); | |
1814 | rtx x1 = XEXP (x, 1); | |
1815 | ||
1816 | if (GET_CODE (y) == PLUS) | |
1817 | { | |
1818 | /* The fact that Y is canonicalized means that this | |
1819 | PLUS rtx is canonicalized. */ | |
1820 | rtx y0 = XEXP (y, 0); | |
1821 | rtx y1 = XEXP (y, 1); | |
1822 | ||
1823 | if (rtx_equal_for_memref_p (x1, y1)) | |
1824 | return memrefs_conflict_p (xsize, x0, ysize, y0, c); | |
1825 | if (rtx_equal_for_memref_p (x0, y0)) | |
1826 | return memrefs_conflict_p (xsize, x1, ysize, y1, c); | |
971ba038 | 1827 | if (CONST_INT_P (x1)) |
5f59c49b | 1828 | { |
971ba038 | 1829 | if (CONST_INT_P (y1)) |
5f59c49b | 1830 | return memrefs_conflict_p (xsize, x0, ysize, y0, |
1831 | c - INTVAL (x1) + INTVAL (y1)); | |
1832 | else | |
1833 | return memrefs_conflict_p (xsize, x0, ysize, y, | |
1834 | c - INTVAL (x1)); | |
1835 | } | |
971ba038 | 1836 | else if (CONST_INT_P (y1)) |
ea0cb7ae | 1837 | return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1)); |
1838 | ||
35d3eedd | 1839 | return 1; |
ea0cb7ae | 1840 | } |
971ba038 | 1841 | else if (CONST_INT_P (x1)) |
ea0cb7ae | 1842 | return memrefs_conflict_p (xsize, x0, ysize, y, c - INTVAL (x1)); |
1843 | } | |
1844 | else if (GET_CODE (y) == PLUS) | |
1845 | { | |
1846 | /* The fact that Y is canonicalized means that this | |
1847 | PLUS rtx is canonicalized. */ | |
1848 | rtx y0 = XEXP (y, 0); | |
1849 | rtx y1 = XEXP (y, 1); | |
1850 | ||
971ba038 | 1851 | if (CONST_INT_P (y1)) |
ea0cb7ae | 1852 | return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1)); |
1853 | else | |
1854 | return 1; | |
1855 | } | |
1856 | ||
1857 | if (GET_CODE (x) == GET_CODE (y)) | |
1858 | switch (GET_CODE (x)) | |
1859 | { | |
1860 | case MULT: | |
1861 | { | |
1862 | /* Handle cases where we expect the second operands to be the | |
1863 | same, and check only whether the first operand would conflict | |
1864 | or not. */ | |
1865 | rtx x0, y0; | |
1866 | rtx x1 = canon_rtx (XEXP (x, 1)); | |
1867 | rtx y1 = canon_rtx (XEXP (y, 1)); | |
1868 | if (! rtx_equal_for_memref_p (x1, y1)) | |
1869 | return 1; | |
1870 | x0 = canon_rtx (XEXP (x, 0)); | |
1871 | y0 = canon_rtx (XEXP (y, 0)); | |
1872 | if (rtx_equal_for_memref_p (x0, y0)) | |
1873 | return (xsize == 0 || ysize == 0 | |
1874 | || (c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)); | |
1875 | ||
1876 | /* Can't properly adjust our sizes. */ | |
971ba038 | 1877 | if (!CONST_INT_P (x1)) |
ea0cb7ae | 1878 | return 1; |
1879 | xsize /= INTVAL (x1); | |
1880 | ysize /= INTVAL (x1); | |
1881 | c /= INTVAL (x1); | |
1882 | return memrefs_conflict_p (xsize, x0, ysize, y0, c); | |
1883 | } | |
99c14947 | 1884 | |
1885 | default: | |
1886 | break; | |
ea0cb7ae | 1887 | } |
1888 | ||
1889 | /* Treat an access through an AND (e.g. a subword access on an Alpha) | |
9342ee68 | 1890 | as an access with indeterminate size. Assume that references |
9fb1c31b | 1891 | besides AND are aligned, so if the size of the other reference is |
1892 | at least as large as the alignment, assume no other overlap. */ | |
971ba038 | 1893 | if (GET_CODE (x) == AND && CONST_INT_P (XEXP (x, 1))) |
9fb1c31b | 1894 | { |
bcdb334e | 1895 | if (GET_CODE (y) == AND || ysize < -INTVAL (XEXP (x, 1))) |
9fb1c31b | 1896 | xsize = -1; |
6285298a | 1897 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), ysize, y, c); |
9fb1c31b | 1898 | } |
971ba038 | 1899 | if (GET_CODE (y) == AND && CONST_INT_P (XEXP (y, 1))) |
1e38bf49 | 1900 | { |
9fb1c31b | 1901 | /* ??? If we are indexing far enough into the array/structure, we |
9342ee68 | 1902 | may yet be able to determine that we can not overlap. But we |
1e38bf49 | 1903 | also need to that we are far enough from the end not to overlap |
9fb1c31b | 1904 | a following reference, so we do nothing with that for now. */ |
bcdb334e | 1905 | if (GET_CODE (x) == AND || xsize < -INTVAL (XEXP (y, 1))) |
9fb1c31b | 1906 | ysize = -1; |
6285298a | 1907 | return memrefs_conflict_p (xsize, x, ysize, canon_rtx (XEXP (y, 0)), c); |
1e38bf49 | 1908 | } |
ea0cb7ae | 1909 | |
1910 | if (CONSTANT_P (x)) | |
1911 | { | |
971ba038 | 1912 | if (CONST_INT_P (x) && CONST_INT_P (y)) |
ea0cb7ae | 1913 | { |
1914 | c += (INTVAL (y) - INTVAL (x)); | |
1e38bf49 | 1915 | return (xsize <= 0 || ysize <= 0 |
ea0cb7ae | 1916 | || (c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)); |
1917 | } | |
1918 | ||
1919 | if (GET_CODE (x) == CONST) | |
1920 | { | |
1921 | if (GET_CODE (y) == CONST) | |
1922 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), | |
1923 | ysize, canon_rtx (XEXP (y, 0)), c); | |
1924 | else | |
1925 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), | |
1926 | ysize, y, c); | |
1927 | } | |
1928 | if (GET_CODE (y) == CONST) | |
1929 | return memrefs_conflict_p (xsize, x, ysize, | |
1930 | canon_rtx (XEXP (y, 0)), c); | |
1931 | ||
1932 | if (CONSTANT_P (y)) | |
15750b1e | 1933 | return (xsize <= 0 || ysize <= 0 |
1e38bf49 | 1934 | || (rtx_equal_for_memref_p (x, y) |
15750b1e | 1935 | && ((c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)))); |
ea0cb7ae | 1936 | |
1937 | return 1; | |
1938 | } | |
1939 | return 1; | |
1940 | } | |
1941 | ||
1942 | /* Functions to compute memory dependencies. | |
1943 | ||
1944 | Since we process the insns in execution order, we can build tables | |
1945 | to keep track of what registers are fixed (and not aliased), what registers | |
1946 | are varying in known ways, and what registers are varying in unknown | |
1947 | ways. | |
1948 | ||
1949 | If both memory references are volatile, then there must always be a | |
1950 | dependence between the two references, since their order can not be | |
1951 | changed. A volatile and non-volatile reference can be interchanged | |
9342ee68 | 1952 | though. |
ea0cb7ae | 1953 | |
71d9e995 | 1954 | A MEM_IN_STRUCT reference at a non-AND varying address can never |
1955 | conflict with a non-MEM_IN_STRUCT reference at a fixed address. We | |
1956 | also must allow AND addresses, because they may generate accesses | |
1957 | outside the object being referenced. This is used to generate | |
1958 | aligned addresses from unaligned addresses, for instance, the alpha | |
1959 | storeqi_unaligned pattern. */ | |
ea0cb7ae | 1960 | |
1961 | /* Read dependence: X is read after read in MEM takes place. There can | |
1962 | only be a dependence here if both reads are volatile. */ | |
1963 | ||
1964 | int | |
52d07779 | 1965 | read_dependence (const_rtx mem, const_rtx x) |
ea0cb7ae | 1966 | { |
1967 | return MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem); | |
1968 | } | |
1969 | ||
6a0934dd | 1970 | /* Returns MEM1 if and only if MEM1 is a scalar at a fixed address and |
1971 | MEM2 is a reference to a structure at a varying address, or returns | |
1972 | MEM2 if vice versa. Otherwise, returns NULL_RTX. If a non-NULL | |
1973 | value is returned MEM1 and MEM2 can never alias. VARIES_P is used | |
1974 | to decide whether or not an address may vary; it should return | |
1617c276 | 1975 | nonzero whenever variation is possible. |
1976 | MEM1_ADDR and MEM2_ADDR are the addresses of MEM1 and MEM2. */ | |
9342ee68 | 1977 | |
52d07779 | 1978 | static const_rtx |
1979 | fixed_scalar_and_varying_struct_p (const_rtx mem1, const_rtx mem2, rtx mem1_addr, | |
aecda0d6 | 1980 | rtx mem2_addr, |
52d07779 | 1981 | bool (*varies_p) (const_rtx, bool)) |
9342ee68 | 1982 | { |
c7f6877a | 1983 | if (! flag_strict_aliasing) |
1984 | return NULL_RTX; | |
1985 | ||
91605b2e | 1986 | if (MEM_ALIAS_SET (mem2) |
1987 | && MEM_SCALAR_P (mem1) && MEM_IN_STRUCT_P (mem2) | |
ea087693 | 1988 | && !varies_p (mem1_addr, 1) && varies_p (mem2_addr, 1)) |
6a0934dd | 1989 | /* MEM1 is a scalar at a fixed address; MEM2 is a struct at a |
1990 | varying address. */ | |
1991 | return mem1; | |
1992 | ||
91605b2e | 1993 | if (MEM_ALIAS_SET (mem1) |
1994 | && MEM_IN_STRUCT_P (mem1) && MEM_SCALAR_P (mem2) | |
ea087693 | 1995 | && varies_p (mem1_addr, 1) && !varies_p (mem2_addr, 1)) |
6a0934dd | 1996 | /* MEM2 is a scalar at a fixed address; MEM1 is a struct at a |
1997 | varying address. */ | |
1998 | return mem2; | |
1999 | ||
2000 | return NULL_RTX; | |
2001 | } | |
2002 | ||
2003 | /* Returns nonzero if something about the mode or address format MEM1 | |
2004 | indicates that it might well alias *anything*. */ | |
2005 | ||
fe69e4fe | 2006 | static int |
52d07779 | 2007 | aliases_everything_p (const_rtx mem) |
6a0934dd | 2008 | { |
6a0934dd | 2009 | if (GET_CODE (XEXP (mem, 0)) == AND) |
0975351b | 2010 | /* If the address is an AND, it's very hard to know at what it is |
6a0934dd | 2011 | actually pointing. */ |
2012 | return 1; | |
9342ee68 | 2013 | |
6a0934dd | 2014 | return 0; |
2015 | } | |
2016 | ||
b10dbbca | 2017 | /* Return true if we can determine that the fields referenced cannot |
2018 | overlap for any pair of objects. */ | |
2019 | ||
2020 | static bool | |
52d07779 | 2021 | nonoverlapping_component_refs_p (const_tree x, const_tree y) |
b10dbbca | 2022 | { |
52d07779 | 2023 | const_tree fieldx, fieldy, typex, typey, orig_y; |
b10dbbca | 2024 | |
b95fdaae | 2025 | if (!flag_strict_aliasing) |
2026 | return false; | |
2027 | ||
b10dbbca | 2028 | do |
2029 | { | |
2030 | /* The comparison has to be done at a common type, since we don't | |
cb0ccc1e | 2031 | know how the inheritance hierarchy works. */ |
b10dbbca | 2032 | orig_y = y; |
2033 | do | |
2034 | { | |
2035 | fieldx = TREE_OPERAND (x, 1); | |
a769a0a7 | 2036 | typex = TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (fieldx)); |
b10dbbca | 2037 | |
2038 | y = orig_y; | |
2039 | do | |
2040 | { | |
2041 | fieldy = TREE_OPERAND (y, 1); | |
a769a0a7 | 2042 | typey = TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (fieldy)); |
b10dbbca | 2043 | |
2044 | if (typex == typey) | |
2045 | goto found; | |
2046 | ||
2047 | y = TREE_OPERAND (y, 0); | |
2048 | } | |
2049 | while (y && TREE_CODE (y) == COMPONENT_REF); | |
2050 | ||
2051 | x = TREE_OPERAND (x, 0); | |
2052 | } | |
2053 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
b10dbbca | 2054 | /* Never found a common type. */ |
a769a0a7 | 2055 | return false; |
b10dbbca | 2056 | |
2057 | found: | |
2058 | /* If we're left with accessing different fields of a structure, | |
2059 | then no overlap. */ | |
2060 | if (TREE_CODE (typex) == RECORD_TYPE | |
2061 | && fieldx != fieldy) | |
2062 | return true; | |
2063 | ||
2064 | /* The comparison on the current field failed. If we're accessing | |
2065 | a very nested structure, look at the next outer level. */ | |
2066 | x = TREE_OPERAND (x, 0); | |
2067 | y = TREE_OPERAND (y, 0); | |
2068 | } | |
2069 | while (x && y | |
2070 | && TREE_CODE (x) == COMPONENT_REF | |
2071 | && TREE_CODE (y) == COMPONENT_REF); | |
9342ee68 | 2072 | |
b10dbbca | 2073 | return false; |
2074 | } | |
2075 | ||
2076 | /* Look at the bottom of the COMPONENT_REF list for a DECL, and return it. */ | |
2077 | ||
2078 | static tree | |
aecda0d6 | 2079 | decl_for_component_ref (tree x) |
b10dbbca | 2080 | { |
2081 | do | |
2082 | { | |
2083 | x = TREE_OPERAND (x, 0); | |
2084 | } | |
2085 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
2086 | ||
2087 | return x && DECL_P (x) ? x : NULL_TREE; | |
2088 | } | |
2089 | ||
2090 | /* Walk up the COMPONENT_REF list and adjust OFFSET to compensate for the | |
2091 | offset of the field reference. */ | |
2092 | ||
2093 | static rtx | |
aecda0d6 | 2094 | adjust_offset_for_component_ref (tree x, rtx offset) |
b10dbbca | 2095 | { |
2096 | HOST_WIDE_INT ioffset; | |
2097 | ||
2098 | if (! offset) | |
2099 | return NULL_RTX; | |
2100 | ||
2101 | ioffset = INTVAL (offset); | |
9342ee68 | 2102 | do |
b10dbbca | 2103 | { |
6374121b | 2104 | tree offset = component_ref_field_offset (x); |
b10dbbca | 2105 | tree field = TREE_OPERAND (x, 1); |
2106 | ||
6374121b | 2107 | if (! host_integerp (offset, 1)) |
b10dbbca | 2108 | return NULL_RTX; |
6374121b | 2109 | ioffset += (tree_low_cst (offset, 1) |
b10dbbca | 2110 | + (tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1) |
2111 | / BITS_PER_UNIT)); | |
2112 | ||
2113 | x = TREE_OPERAND (x, 0); | |
2114 | } | |
2115 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
2116 | ||
2117 | return GEN_INT (ioffset); | |
2118 | } | |
2119 | ||
d716ce75 | 2120 | /* Return nonzero if we can determine the exprs corresponding to memrefs |
ddb3d16f | 2121 | X and Y and they do not overlap. */ |
2122 | ||
5fe61d21 | 2123 | int |
52d07779 | 2124 | nonoverlapping_memrefs_p (const_rtx x, const_rtx y) |
ddb3d16f | 2125 | { |
b10dbbca | 2126 | tree exprx = MEM_EXPR (x), expry = MEM_EXPR (y); |
ddb3d16f | 2127 | rtx rtlx, rtly; |
2128 | rtx basex, basey; | |
b10dbbca | 2129 | rtx moffsetx, moffsety; |
ddb3d16f | 2130 | HOST_WIDE_INT offsetx = 0, offsety = 0, sizex, sizey, tem; |
2131 | ||
b10dbbca | 2132 | /* Unless both have exprs, we can't tell anything. */ |
2133 | if (exprx == 0 || expry == 0) | |
2134 | return 0; | |
a0c938f0 | 2135 | |
b10dbbca | 2136 | /* If both are field references, we may be able to determine something. */ |
2137 | if (TREE_CODE (exprx) == COMPONENT_REF | |
2138 | && TREE_CODE (expry) == COMPONENT_REF | |
2139 | && nonoverlapping_component_refs_p (exprx, expry)) | |
2140 | return 1; | |
2141 | ||
a0c938f0 | 2142 | |
b10dbbca | 2143 | /* If the field reference test failed, look at the DECLs involved. */ |
2144 | moffsetx = MEM_OFFSET (x); | |
2145 | if (TREE_CODE (exprx) == COMPONENT_REF) | |
2146 | { | |
f7d118a9 | 2147 | if (TREE_CODE (expry) == VAR_DECL |
2148 | && POINTER_TYPE_P (TREE_TYPE (expry))) | |
2149 | { | |
2150 | tree field = TREE_OPERAND (exprx, 1); | |
2151 | tree fieldcontext = DECL_FIELD_CONTEXT (field); | |
2152 | if (ipa_type_escape_field_does_not_clobber_p (fieldcontext, | |
2153 | TREE_TYPE (field))) | |
a0c938f0 | 2154 | return 1; |
f7d118a9 | 2155 | } |
2156 | { | |
2157 | tree t = decl_for_component_ref (exprx); | |
2158 | if (! t) | |
2159 | return 0; | |
2160 | moffsetx = adjust_offset_for_component_ref (exprx, moffsetx); | |
2161 | exprx = t; | |
2162 | } | |
b10dbbca | 2163 | } |
2a448a75 | 2164 | else if (INDIRECT_REF_P (exprx)) |
2d8fe5d0 | 2165 | { |
2166 | exprx = TREE_OPERAND (exprx, 0); | |
2167 | if (flag_argument_noalias < 2 | |
2168 | || TREE_CODE (exprx) != PARM_DECL) | |
2169 | return 0; | |
2170 | } | |
2171 | ||
b10dbbca | 2172 | moffsety = MEM_OFFSET (y); |
2173 | if (TREE_CODE (expry) == COMPONENT_REF) | |
2174 | { | |
f7d118a9 | 2175 | if (TREE_CODE (exprx) == VAR_DECL |
2176 | && POINTER_TYPE_P (TREE_TYPE (exprx))) | |
2177 | { | |
2178 | tree field = TREE_OPERAND (expry, 1); | |
2179 | tree fieldcontext = DECL_FIELD_CONTEXT (field); | |
2180 | if (ipa_type_escape_field_does_not_clobber_p (fieldcontext, | |
2181 | TREE_TYPE (field))) | |
a0c938f0 | 2182 | return 1; |
f7d118a9 | 2183 | } |
2184 | { | |
2185 | tree t = decl_for_component_ref (expry); | |
2186 | if (! t) | |
2187 | return 0; | |
2188 | moffsety = adjust_offset_for_component_ref (expry, moffsety); | |
2189 | expry = t; | |
2190 | } | |
b10dbbca | 2191 | } |
2a448a75 | 2192 | else if (INDIRECT_REF_P (expry)) |
2d8fe5d0 | 2193 | { |
2194 | expry = TREE_OPERAND (expry, 0); | |
2195 | if (flag_argument_noalias < 2 | |
2196 | || TREE_CODE (expry) != PARM_DECL) | |
2197 | return 0; | |
2198 | } | |
b10dbbca | 2199 | |
2200 | if (! DECL_P (exprx) || ! DECL_P (expry)) | |
ddb3d16f | 2201 | return 0; |
2202 | ||
119147d1 | 2203 | /* With invalid code we can end up storing into the constant pool. |
2204 | Bail out to avoid ICEing when creating RTL for this. | |
2205 | See gfortran.dg/lto/20091028-2_0.f90. */ | |
2206 | if (TREE_CODE (exprx) == CONST_DECL | |
2207 | || TREE_CODE (expry) == CONST_DECL) | |
2208 | return 1; | |
2209 | ||
b10dbbca | 2210 | rtlx = DECL_RTL (exprx); |
2211 | rtly = DECL_RTL (expry); | |
ddb3d16f | 2212 | |
10e949c1 | 2213 | /* If either RTL is not a MEM, it must be a REG or CONCAT, meaning they |
2214 | can't overlap unless they are the same because we never reuse that part | |
2215 | of the stack frame used for locals for spilled pseudos. */ | |
e16ceb8e | 2216 | if ((!MEM_P (rtlx) || !MEM_P (rtly)) |
10e949c1 | 2217 | && ! rtx_equal_p (rtlx, rtly)) |
ddb3d16f | 2218 | return 1; |
2219 | ||
bd1a81f7 | 2220 | /* If we have MEMs refering to different address spaces (which can |
2221 | potentially overlap), we cannot easily tell from the addresses | |
2222 | whether the references overlap. */ | |
2223 | if (MEM_P (rtlx) && MEM_P (rtly) | |
2224 | && MEM_ADDR_SPACE (rtlx) != MEM_ADDR_SPACE (rtly)) | |
2225 | return 0; | |
2226 | ||
ddb3d16f | 2227 | /* Get the base and offsets of both decls. If either is a register, we |
2228 | know both are and are the same, so use that as the base. The only | |
2229 | we can avoid overlap is if we can deduce that they are nonoverlapping | |
2230 | pieces of that decl, which is very rare. */ | |
e16ceb8e | 2231 | basex = MEM_P (rtlx) ? XEXP (rtlx, 0) : rtlx; |
971ba038 | 2232 | if (GET_CODE (basex) == PLUS && CONST_INT_P (XEXP (basex, 1))) |
ddb3d16f | 2233 | offsetx = INTVAL (XEXP (basex, 1)), basex = XEXP (basex, 0); |
2234 | ||
e16ceb8e | 2235 | basey = MEM_P (rtly) ? XEXP (rtly, 0) : rtly; |
971ba038 | 2236 | if (GET_CODE (basey) == PLUS && CONST_INT_P (XEXP (basey, 1))) |
ddb3d16f | 2237 | offsety = INTVAL (XEXP (basey, 1)), basey = XEXP (basey, 0); |
2238 | ||
c9c48480 | 2239 | /* If the bases are different, we know they do not overlap if both |
9342ee68 | 2240 | are constants or if one is a constant and the other a pointer into the |
c9c48480 | 2241 | stack frame. Otherwise a different base means we can't tell if they |
2242 | overlap or not. */ | |
2243 | if (! rtx_equal_p (basex, basey)) | |
9342ee68 | 2244 | return ((CONSTANT_P (basex) && CONSTANT_P (basey)) |
2245 | || (CONSTANT_P (basex) && REG_P (basey) | |
2246 | && REGNO_PTR_FRAME_P (REGNO (basey))) | |
2247 | || (CONSTANT_P (basey) && REG_P (basex) | |
2248 | && REGNO_PTR_FRAME_P (REGNO (basex)))); | |
ddb3d16f | 2249 | |
e16ceb8e | 2250 | sizex = (!MEM_P (rtlx) ? (int) GET_MODE_SIZE (GET_MODE (rtlx)) |
ddb3d16f | 2251 | : MEM_SIZE (rtlx) ? INTVAL (MEM_SIZE (rtlx)) |
2252 | : -1); | |
e16ceb8e | 2253 | sizey = (!MEM_P (rtly) ? (int) GET_MODE_SIZE (GET_MODE (rtly)) |
ddb3d16f | 2254 | : MEM_SIZE (rtly) ? INTVAL (MEM_SIZE (rtly)) : |
2255 | -1); | |
2256 | ||
dc2dfdb6 | 2257 | /* If we have an offset for either memref, it can update the values computed |
2258 | above. */ | |
b10dbbca | 2259 | if (moffsetx) |
2260 | offsetx += INTVAL (moffsetx), sizex -= INTVAL (moffsetx); | |
2261 | if (moffsety) | |
2262 | offsety += INTVAL (moffsety), sizey -= INTVAL (moffsety); | |
ddb3d16f | 2263 | |
dc2dfdb6 | 2264 | /* If a memref has both a size and an offset, we can use the smaller size. |
203c9fee | 2265 | We can't do this if the offset isn't known because we must view this |
dc2dfdb6 | 2266 | memref as being anywhere inside the DECL's MEM. */ |
b10dbbca | 2267 | if (MEM_SIZE (x) && moffsetx) |
ddb3d16f | 2268 | sizex = INTVAL (MEM_SIZE (x)); |
b10dbbca | 2269 | if (MEM_SIZE (y) && moffsety) |
ddb3d16f | 2270 | sizey = INTVAL (MEM_SIZE (y)); |
2271 | ||
2272 | /* Put the values of the memref with the lower offset in X's values. */ | |
2273 | if (offsetx > offsety) | |
2274 | { | |
2275 | tem = offsetx, offsetx = offsety, offsety = tem; | |
2276 | tem = sizex, sizex = sizey, sizey = tem; | |
2277 | } | |
2278 | ||
2279 | /* If we don't know the size of the lower-offset value, we can't tell | |
2280 | if they conflict. Otherwise, we do the test. */ | |
906923ba | 2281 | return sizex >= 0 && offsety >= offsetx + sizex; |
ddb3d16f | 2282 | } |
2283 | ||
ea0cb7ae | 2284 | /* True dependence: X is read after store in MEM takes place. */ |
2285 | ||
2286 | int | |
52d07779 | 2287 | true_dependence (const_rtx mem, enum machine_mode mem_mode, const_rtx x, |
2288 | bool (*varies) (const_rtx, bool)) | |
ea0cb7ae | 2289 | { |
19cb6b50 | 2290 | rtx x_addr, mem_addr; |
9ee7cac5 | 2291 | rtx base; |
ea0cb7ae | 2292 | |
2293 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) | |
2294 | return 1; | |
2295 | ||
a57f4c4d | 2296 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
67837170 | 2297 | This is used in epilogue deallocation functions, and in cselib. */ |
a57f4c4d | 2298 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) |
2299 | return 1; | |
2300 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
2301 | return 1; | |
c94cfd1c | 2302 | if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER |
2303 | || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER) | |
2304 | return 1; | |
a57f4c4d | 2305 | |
b5ba9f3a | 2306 | if (DIFFERENT_ALIAS_SETS_P (x, mem)) |
2307 | return 0; | |
2308 | ||
b04fab2a | 2309 | /* Read-only memory is by definition never modified, and therefore can't |
2310 | conflict with anything. We don't expect to find read-only set on MEM, | |
a53ff4c1 | 2311 | but stupid user tricks can produce them, so don't die. */ |
b04fab2a | 2312 | if (MEM_READONLY_P (x)) |
ea0cb7ae | 2313 | return 0; |
2314 | ||
ddb3d16f | 2315 | if (nonoverlapping_memrefs_p (mem, x)) |
2316 | return 0; | |
2317 | ||
bd1a81f7 | 2318 | /* If we have MEMs refering to different address spaces (which can |
2319 | potentially overlap), we cannot easily tell from the addresses | |
2320 | whether the references overlap. */ | |
2321 | if (MEM_ADDR_SPACE (mem) != MEM_ADDR_SPACE (x)) | |
2322 | return 1; | |
2323 | ||
9fb1c31b | 2324 | if (mem_mode == VOIDmode) |
2325 | mem_mode = GET_MODE (mem); | |
2326 | ||
1617c276 | 2327 | x_addr = get_addr (XEXP (x, 0)); |
2328 | mem_addr = get_addr (XEXP (mem, 0)); | |
2329 | ||
002fe3cb | 2330 | base = find_base_term (x_addr); |
2331 | if (base && (GET_CODE (base) == LABEL_REF | |
2332 | || (GET_CODE (base) == SYMBOL_REF | |
2333 | && CONSTANT_POOL_ADDRESS_P (base)))) | |
2334 | return 0; | |
2335 | ||
1617c276 | 2336 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), mem_mode)) |
3ad3a0ed | 2337 | return 0; |
2338 | ||
1617c276 | 2339 | x_addr = canon_rtx (x_addr); |
2340 | mem_addr = canon_rtx (mem_addr); | |
35d3eedd | 2341 | |
4958fe6e | 2342 | if (! memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr, |
2343 | SIZE_FOR_MODE (x), x_addr, 0)) | |
2344 | return 0; | |
2345 | ||
6a0934dd | 2346 | if (aliases_everything_p (x)) |
4958fe6e | 2347 | return 1; |
2348 | ||
35a3065a | 2349 | /* We cannot use aliases_everything_p to test MEM, since we must look |
6a0934dd | 2350 | at MEM_MODE, rather than GET_MODE (MEM). */ |
2351 | if (mem_mode == QImode || GET_CODE (mem_addr) == AND) | |
8e802be9 | 2352 | return 1; |
2353 | ||
2354 | /* In true_dependence we also allow BLKmode to alias anything. Why | |
2355 | don't we do this in anti_dependence and output_dependence? */ | |
2356 | if (mem_mode == BLKmode || GET_MODE (x) == BLKmode) | |
2357 | return 1; | |
2358 | ||
3a443843 | 2359 | if (fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, varies)) |
2360 | return 0; | |
2361 | ||
2362 | return rtx_refs_may_alias_p (x, mem, true); | |
8e802be9 | 2363 | } |
2364 | ||
2365 | /* Canonical true dependence: X is read after store in MEM takes place. | |
9342ee68 | 2366 | Variant of true_dependence which assumes MEM has already been |
2367 | canonicalized (hence we no longer do that here). | |
2368 | The mem_addr argument has been added, since true_dependence computed | |
82d2c88b | 2369 | this value prior to canonicalizing. |
2370 | If x_addr is non-NULL, it is used in preference of XEXP (x, 0). */ | |
8e802be9 | 2371 | |
2372 | int | |
52d07779 | 2373 | canon_true_dependence (const_rtx mem, enum machine_mode mem_mode, rtx mem_addr, |
82d2c88b | 2374 | const_rtx x, rtx x_addr, bool (*varies) (const_rtx, bool)) |
8e802be9 | 2375 | { |
8e802be9 | 2376 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) |
2377 | return 1; | |
2378 | ||
d7b592b0 | 2379 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
2380 | This is used in epilogue deallocation functions. */ | |
2381 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) | |
2382 | return 1; | |
2383 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
2384 | return 1; | |
c94cfd1c | 2385 | if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER |
2386 | || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER) | |
2387 | return 1; | |
d7b592b0 | 2388 | |
8e802be9 | 2389 | if (DIFFERENT_ALIAS_SETS_P (x, mem)) |
2390 | return 0; | |
2391 | ||
b04fab2a | 2392 | /* Read-only memory is by definition never modified, and therefore can't |
2393 | conflict with anything. We don't expect to find read-only set on MEM, | |
a53ff4c1 | 2394 | but stupid user tricks can produce them, so don't die. */ |
b04fab2a | 2395 | if (MEM_READONLY_P (x)) |
8e802be9 | 2396 | return 0; |
2397 | ||
ddb3d16f | 2398 | if (nonoverlapping_memrefs_p (x, mem)) |
2399 | return 0; | |
2400 | ||
bd1a81f7 | 2401 | /* If we have MEMs refering to different address spaces (which can |
2402 | potentially overlap), we cannot easily tell from the addresses | |
2403 | whether the references overlap. */ | |
2404 | if (MEM_ADDR_SPACE (mem) != MEM_ADDR_SPACE (x)) | |
2405 | return 1; | |
2406 | ||
82d2c88b | 2407 | if (! x_addr) |
2408 | x_addr = get_addr (XEXP (x, 0)); | |
8e802be9 | 2409 | |
2410 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), mem_mode)) | |
2411 | return 0; | |
2412 | ||
2413 | x_addr = canon_rtx (x_addr); | |
2414 | if (! memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr, | |
2415 | SIZE_FOR_MODE (x), x_addr, 0)) | |
2416 | return 0; | |
2417 | ||
2418 | if (aliases_everything_p (x)) | |
2419 | return 1; | |
2420 | ||
35a3065a | 2421 | /* We cannot use aliases_everything_p to test MEM, since we must look |
8e802be9 | 2422 | at MEM_MODE, rather than GET_MODE (MEM). */ |
2423 | if (mem_mode == QImode || GET_CODE (mem_addr) == AND) | |
6a0934dd | 2424 | return 1; |
4958fe6e | 2425 | |
6a0934dd | 2426 | /* In true_dependence we also allow BLKmode to alias anything. Why |
2427 | don't we do this in anti_dependence and output_dependence? */ | |
2428 | if (mem_mode == BLKmode || GET_MODE (x) == BLKmode) | |
2429 | return 1; | |
4958fe6e | 2430 | |
3a443843 | 2431 | if (fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, varies)) |
2432 | return 0; | |
2433 | ||
2434 | return rtx_refs_may_alias_p (x, mem, true); | |
ea0cb7ae | 2435 | } |
2436 | ||
d10cfa8d | 2437 | /* Returns nonzero if a write to X might alias a previous read from |
b04fab2a | 2438 | (or, if WRITEP is nonzero, a write to) MEM. */ |
ea0cb7ae | 2439 | |
fe69e4fe | 2440 | static int |
52d07779 | 2441 | write_dependence_p (const_rtx mem, const_rtx x, int writep) |
ea0cb7ae | 2442 | { |
35d3eedd | 2443 | rtx x_addr, mem_addr; |
52d07779 | 2444 | const_rtx fixed_scalar; |
9ee7cac5 | 2445 | rtx base; |
35d3eedd | 2446 | |
ea0cb7ae | 2447 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) |
2448 | return 1; | |
2449 | ||
a57f4c4d | 2450 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
2451 | This is used in epilogue deallocation functions. */ | |
2452 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) | |
2453 | return 1; | |
2454 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
2455 | return 1; | |
c94cfd1c | 2456 | if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER |
2457 | || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER) | |
2458 | return 1; | |
a57f4c4d | 2459 | |
b04fab2a | 2460 | /* A read from read-only memory can't conflict with read-write memory. */ |
2461 | if (!writep && MEM_READONLY_P (mem)) | |
2462 | return 0; | |
002fe3cb | 2463 | |
ddb3d16f | 2464 | if (nonoverlapping_memrefs_p (x, mem)) |
2465 | return 0; | |
2466 | ||
bd1a81f7 | 2467 | /* If we have MEMs refering to different address spaces (which can |
2468 | potentially overlap), we cannot easily tell from the addresses | |
2469 | whether the references overlap. */ | |
2470 | if (MEM_ADDR_SPACE (mem) != MEM_ADDR_SPACE (x)) | |
2471 | return 1; | |
2472 | ||
002fe3cb | 2473 | x_addr = get_addr (XEXP (x, 0)); |
2474 | mem_addr = get_addr (XEXP (mem, 0)); | |
2475 | ||
9ee7cac5 | 2476 | if (! writep) |
2477 | { | |
002fe3cb | 2478 | base = find_base_term (mem_addr); |
9ee7cac5 | 2479 | if (base && (GET_CODE (base) == LABEL_REF |
2480 | || (GET_CODE (base) == SYMBOL_REF | |
2481 | && CONSTANT_POOL_ADDRESS_P (base)))) | |
2482 | return 0; | |
2483 | } | |
2484 | ||
1617c276 | 2485 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), |
2486 | GET_MODE (mem))) | |
b5ba9f3a | 2487 | return 0; |
2488 | ||
1617c276 | 2489 | x_addr = canon_rtx (x_addr); |
2490 | mem_addr = canon_rtx (mem_addr); | |
35d3eedd | 2491 | |
6a0934dd | 2492 | if (!memrefs_conflict_p (SIZE_FOR_MODE (mem), mem_addr, |
2493 | SIZE_FOR_MODE (x), x_addr, 0)) | |
2494 | return 0; | |
2495 | ||
9342ee68 | 2496 | fixed_scalar |
1617c276 | 2497 | = fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, |
2498 | rtx_addr_varies_p); | |
2499 | ||
3a443843 | 2500 | if ((fixed_scalar == mem && !aliases_everything_p (x)) |
2501 | || (fixed_scalar == x && !aliases_everything_p (mem))) | |
2502 | return 0; | |
2503 | ||
2504 | return rtx_refs_may_alias_p (x, mem, false); | |
6a0934dd | 2505 | } |
2506 | ||
2507 | /* Anti dependence: X is written after read in MEM takes place. */ | |
2508 | ||
2509 | int | |
52d07779 | 2510 | anti_dependence (const_rtx mem, const_rtx x) |
6a0934dd | 2511 | { |
b04fab2a | 2512 | return write_dependence_p (mem, x, /*writep=*/0); |
ea0cb7ae | 2513 | } |
2514 | ||
2515 | /* Output dependence: X is written after store in MEM takes place. */ | |
2516 | ||
2517 | int | |
52d07779 | 2518 | output_dependence (const_rtx mem, const_rtx x) |
ea0cb7ae | 2519 | { |
b04fab2a | 2520 | return write_dependence_p (mem, x, /*writep=*/1); |
ea0cb7ae | 2521 | } |
c352cbc7 | 2522 | \f |
35d3eedd | 2523 | |
35d3eedd | 2524 | void |
6d8b68a3 | 2525 | init_alias_target (void) |
35d3eedd | 2526 | { |
19cb6b50 | 2527 | int i; |
35d3eedd | 2528 | |
6d8b68a3 | 2529 | memset (static_reg_base_value, 0, sizeof static_reg_base_value); |
2530 | ||
35d3eedd | 2531 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) |
2532 | /* Check whether this register can hold an incoming pointer | |
2533 | argument. FUNCTION_ARG_REGNO_P tests outgoing register | |
2c0e001b | 2534 | numbers, so translate if necessary due to register windows. */ |
35d3eedd | 2535 | if (FUNCTION_ARG_REGNO_P (OUTGOING_REGNO (i)) |
2536 | && HARD_REGNO_MODE_OK (i, Pmode)) | |
0c7f5242 | 2537 | static_reg_base_value[i] |
2538 | = gen_rtx_ADDRESS (VOIDmode, gen_rtx_REG (Pmode, i)); | |
2539 | ||
0c7f5242 | 2540 | static_reg_base_value[STACK_POINTER_REGNUM] |
2541 | = gen_rtx_ADDRESS (Pmode, stack_pointer_rtx); | |
2542 | static_reg_base_value[ARG_POINTER_REGNUM] | |
2543 | = gen_rtx_ADDRESS (Pmode, arg_pointer_rtx); | |
2544 | static_reg_base_value[FRAME_POINTER_REGNUM] | |
2545 | = gen_rtx_ADDRESS (Pmode, frame_pointer_rtx); | |
2546 | #if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM | |
2547 | static_reg_base_value[HARD_FRAME_POINTER_REGNUM] | |
2548 | = gen_rtx_ADDRESS (Pmode, hard_frame_pointer_rtx); | |
2549 | #endif | |
2550 | } | |
2551 | ||
c7bf7428 | 2552 | /* Set MEMORY_MODIFIED when X modifies DATA (that is assumed |
2553 | to be memory reference. */ | |
2554 | static bool memory_modified; | |
2555 | static void | |
a80f1c6c | 2556 | memory_modified_1 (rtx x, const_rtx pat ATTRIBUTE_UNUSED, void *data) |
c7bf7428 | 2557 | { |
e16ceb8e | 2558 | if (MEM_P (x)) |
c7bf7428 | 2559 | { |
5493cb9a | 2560 | if (anti_dependence (x, (const_rtx)data) || output_dependence (x, (const_rtx)data)) |
c7bf7428 | 2561 | memory_modified = true; |
2562 | } | |
2563 | } | |
2564 | ||
2565 | ||
2566 | /* Return true when INSN possibly modify memory contents of MEM | |
0c6d8c36 | 2567 | (i.e. address can be modified). */ |
c7bf7428 | 2568 | bool |
5493cb9a | 2569 | memory_modified_in_insn_p (const_rtx mem, const_rtx insn) |
c7bf7428 | 2570 | { |
2571 | if (!INSN_P (insn)) | |
2572 | return false; | |
2573 | memory_modified = false; | |
a80f1c6c | 2574 | note_stores (PATTERN (insn), memory_modified_1, CONST_CAST_RTX(mem)); |
c7bf7428 | 2575 | return memory_modified; |
2576 | } | |
2577 | ||
73f5c1e3 | 2578 | /* Initialize the aliasing machinery. Initialize the REG_KNOWN_VALUE |
2579 | array. */ | |
2580 | ||
ea0cb7ae | 2581 | void |
aecda0d6 | 2582 | init_alias_analysis (void) |
ea0cb7ae | 2583 | { |
e5b19a8c | 2584 | unsigned int maxreg = max_reg_num (); |
37b864db | 2585 | int changed, pass; |
19cb6b50 | 2586 | int i; |
2587 | unsigned int ui; | |
2588 | rtx insn; | |
ea0cb7ae | 2589 | |
376c21d1 | 2590 | timevar_push (TV_ALIAS_ANALYSIS); |
2591 | ||
12cb06ad | 2592 | reg_known_value_size = maxreg - FIRST_PSEUDO_REGISTER; |
364c0c59 | 2593 | reg_known_value = GGC_CNEWVEC (rtx, reg_known_value_size); |
2594 | reg_known_equiv_p = XCNEWVEC (bool, reg_known_value_size); | |
ea0cb7ae | 2595 | |
980f3285 | 2596 | /* If we have memory allocated from the previous run, use it. */ |
e5b19a8c | 2597 | if (old_reg_base_value) |
980f3285 | 2598 | reg_base_value = old_reg_base_value; |
2599 | ||
2600 | if (reg_base_value) | |
2601 | VEC_truncate (rtx, reg_base_value, 0); | |
2602 | ||
e85c2c2d | 2603 | VEC_safe_grow_cleared (rtx, gc, reg_base_value, maxreg); |
c2e94b25 | 2604 | |
4c36ffe6 | 2605 | new_reg_base_value = XNEWVEC (rtx, maxreg); |
2606 | reg_seen = XNEWVEC (char, maxreg); | |
06c5c535 | 2607 | |
2608 | /* The basic idea is that each pass through this loop will use the | |
2609 | "constant" information from the previous pass to propagate alias | |
2610 | information through another level of assignments. | |
2611 | ||
2612 | This could get expensive if the assignment chains are long. Maybe | |
2613 | we should throttle the number of iterations, possibly based on | |
35d3eedd | 2614 | the optimization level or flag_expensive_optimizations. |
06c5c535 | 2615 | |
2616 | We could propagate more information in the first pass by making use | |
3072d30e | 2617 | of DF_REG_DEF_COUNT to determine immediately that the alias information |
37b864db | 2618 | for a pseudo is "constant". |
2619 | ||
2620 | A program with an uninitialized variable can cause an infinite loop | |
2621 | here. Instead of doing a full dataflow analysis to detect such problems | |
2622 | we just cap the number of iterations for the loop. | |
2623 | ||
2624 | The state of the arrays for the set chain in question does not matter | |
2625 | since the program has undefined behavior. */ | |
35d3eedd | 2626 | |
37b864db | 2627 | pass = 0; |
35d3eedd | 2628 | do |
06c5c535 | 2629 | { |
2630 | /* Assume nothing will change this iteration of the loop. */ | |
2631 | changed = 0; | |
2632 | ||
06c5c535 | 2633 | /* We want to assign the same IDs each iteration of this loop, so |
2634 | start counting from zero each iteration of the loop. */ | |
2635 | unique_id = 0; | |
2636 | ||
35a3065a | 2637 | /* We're at the start of the function each iteration through the |
06c5c535 | 2638 | loop, so we're copying arguments. */ |
e5be0cc6 | 2639 | copying_arguments = true; |
ea0cb7ae | 2640 | |
35d3eedd | 2641 | /* Wipe the potential alias information clean for this pass. */ |
e5b19a8c | 2642 | memset (new_reg_base_value, 0, maxreg * sizeof (rtx)); |
f0ad0992 | 2643 | |
35d3eedd | 2644 | /* Wipe the reg_seen array clean. */ |
e5b19a8c | 2645 | memset (reg_seen, 0, maxreg); |
ea0cb7ae | 2646 | |
35d3eedd | 2647 | /* Mark all hard registers which may contain an address. |
2648 | The stack, frame and argument pointers may contain an address. | |
2649 | An argument register which can hold a Pmode value may contain | |
2650 | an address even if it is not in BASE_REGS. | |
f0ad0992 | 2651 | |
35d3eedd | 2652 | The address expression is VOIDmode for an argument and |
2653 | Pmode for other registers. */ | |
2654 | ||
e26fd9bc | 2655 | memcpy (new_reg_base_value, static_reg_base_value, |
2656 | FIRST_PSEUDO_REGISTER * sizeof (rtx)); | |
35d3eedd | 2657 | |
06c5c535 | 2658 | /* Walk the insns adding values to the new_reg_base_value array. */ |
2659 | for (insn = get_insns (); insn; insn = NEXT_INSN (insn)) | |
ea0cb7ae | 2660 | { |
9204e736 | 2661 | if (INSN_P (insn)) |
06c5c535 | 2662 | { |
35d3eedd | 2663 | rtx note, set; |
d6cb6164 | 2664 | |
2665 | #if defined (HAVE_prologue) || defined (HAVE_epilogue) | |
35a3065a | 2666 | /* The prologue/epilogue insns are not threaded onto the |
fd037eda | 2667 | insn chain until after reload has completed. Thus, |
2668 | there is no sense wasting time checking if INSN is in | |
2669 | the prologue/epilogue until after reload has completed. */ | |
2670 | if (reload_completed | |
2671 | && prologue_epilogue_contains (insn)) | |
d6cb6164 | 2672 | continue; |
2673 | #endif | |
2674 | ||
06c5c535 | 2675 | /* If this insn has a noalias note, process it, Otherwise, |
a0c938f0 | 2676 | scan for sets. A simple set will have no side effects |
2677 | which could change the base value of any other register. */ | |
35d3eedd | 2678 | |
06c5c535 | 2679 | if (GET_CODE (PATTERN (insn)) == SET |
d6cb6164 | 2680 | && REG_NOTES (insn) != 0 |
2681 | && find_reg_note (insn, REG_NOALIAS, NULL_RTX)) | |
ec8895d7 | 2682 | record_set (SET_DEST (PATTERN (insn)), NULL_RTX, NULL); |
06c5c535 | 2683 | else |
ec8895d7 | 2684 | note_stores (PATTERN (insn), record_set, NULL); |
35d3eedd | 2685 | |
2686 | set = single_set (insn); | |
2687 | ||
2688 | if (set != 0 | |
8ad4c111 | 2689 | && REG_P (SET_DEST (set)) |
9db10305 | 2690 | && REGNO (SET_DEST (set)) >= FIRST_PSEUDO_REGISTER) |
35d3eedd | 2691 | { |
9db10305 | 2692 | unsigned int regno = REGNO (SET_DEST (set)); |
970c0c06 | 2693 | rtx src = SET_SRC (set); |
12cb06ad | 2694 | rtx t; |
970c0c06 | 2695 | |
750a330e | 2696 | note = find_reg_equal_equiv_note (insn); |
2697 | if (note && REG_NOTE_KIND (note) == REG_EQUAL | |
3072d30e | 2698 | && DF_REG_DEF_COUNT (regno) != 1) |
750a330e | 2699 | note = NULL_RTX; |
2700 | ||
2701 | if (note != NULL_RTX | |
970c0c06 | 2702 | && GET_CODE (XEXP (note, 0)) != EXPR_LIST |
97fb4325 | 2703 | && ! rtx_varies_p (XEXP (note, 0), 1) |
12cb06ad | 2704 | && ! reg_overlap_mentioned_p (SET_DEST (set), |
2705 | XEXP (note, 0))) | |
970c0c06 | 2706 | { |
12cb06ad | 2707 | set_reg_known_value (regno, XEXP (note, 0)); |
2708 | set_reg_known_equiv_p (regno, | |
2709 | REG_NOTE_KIND (note) == REG_EQUIV); | |
970c0c06 | 2710 | } |
3072d30e | 2711 | else if (DF_REG_DEF_COUNT (regno) == 1 |
970c0c06 | 2712 | && GET_CODE (src) == PLUS |
8ad4c111 | 2713 | && REG_P (XEXP (src, 0)) |
12cb06ad | 2714 | && (t = get_reg_known_value (REGNO (XEXP (src, 0)))) |
971ba038 | 2715 | && CONST_INT_P (XEXP (src, 1))) |
970c0c06 | 2716 | { |
12cb06ad | 2717 | t = plus_constant (t, INTVAL (XEXP (src, 1))); |
2718 | set_reg_known_value (regno, t); | |
2719 | set_reg_known_equiv_p (regno, 0); | |
970c0c06 | 2720 | } |
3072d30e | 2721 | else if (DF_REG_DEF_COUNT (regno) == 1 |
970c0c06 | 2722 | && ! rtx_varies_p (src, 1)) |
2723 | { | |
12cb06ad | 2724 | set_reg_known_value (regno, src); |
2725 | set_reg_known_equiv_p (regno, 0); | |
970c0c06 | 2726 | } |
35d3eedd | 2727 | } |
06c5c535 | 2728 | } |
6d7dc5b9 | 2729 | else if (NOTE_P (insn) |
ad4583d9 | 2730 | && NOTE_KIND (insn) == NOTE_INSN_FUNCTION_BEG) |
e5be0cc6 | 2731 | copying_arguments = false; |
35d3eedd | 2732 | } |
06c5c535 | 2733 | |
35d3eedd | 2734 | /* Now propagate values from new_reg_base_value to reg_base_value. */ |
d4473c84 | 2735 | gcc_assert (maxreg == (unsigned int) max_reg_num ()); |
a0c938f0 | 2736 | |
e5b19a8c | 2737 | for (ui = 0; ui < maxreg; ui++) |
35d3eedd | 2738 | { |
274c11d8 | 2739 | if (new_reg_base_value[ui] |
980f3285 | 2740 | && new_reg_base_value[ui] != VEC_index (rtx, reg_base_value, ui) |
e5b19a8c | 2741 | && ! rtx_equal_p (new_reg_base_value[ui], |
980f3285 | 2742 | VEC_index (rtx, reg_base_value, ui))) |
06c5c535 | 2743 | { |
980f3285 | 2744 | VEC_replace (rtx, reg_base_value, ui, new_reg_base_value[ui]); |
35d3eedd | 2745 | changed = 1; |
06c5c535 | 2746 | } |
ea0cb7ae | 2747 | } |
ea0cb7ae | 2748 | } |
35d3eedd | 2749 | while (changed && ++pass < MAX_ALIAS_LOOP_PASSES); |
ea0cb7ae | 2750 | |
2751 | /* Fill in the remaining entries. */ | |
12cb06ad | 2752 | for (i = 0; i < (int)reg_known_value_size; i++) |
ea0cb7ae | 2753 | if (reg_known_value[i] == 0) |
12cb06ad | 2754 | reg_known_value[i] = regno_reg_rtx[i + FIRST_PSEUDO_REGISTER]; |
ea0cb7ae | 2755 | |
7098ef4a | 2756 | /* Clean up. */ |
2757 | free (new_reg_base_value); | |
06c5c535 | 2758 | new_reg_base_value = 0; |
7098ef4a | 2759 | free (reg_seen); |
ea0cb7ae | 2760 | reg_seen = 0; |
376c21d1 | 2761 | timevar_pop (TV_ALIAS_ANALYSIS); |
ea0cb7ae | 2762 | } |
2763 | ||
2764 | void | |
aecda0d6 | 2765 | end_alias_analysis (void) |
ea0cb7ae | 2766 | { |
e5b19a8c | 2767 | old_reg_base_value = reg_base_value; |
12cb06ad | 2768 | ggc_free (reg_known_value); |
ea0cb7ae | 2769 | reg_known_value = 0; |
c2e94b25 | 2770 | reg_known_value_size = 0; |
12cb06ad | 2771 | free (reg_known_equiv_p); |
7098ef4a | 2772 | reg_known_equiv_p = 0; |
ea0cb7ae | 2773 | } |
1f3233d1 | 2774 | |
2775 | #include "gt-alias.h" |