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9ae8ffe7 | 1 | /* Alias analysis for GNU C |
62e5bf5d | 2 | Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, |
66647d44 | 3 | 2007, 2008, 2009 Free Software Foundation, Inc. |
9ae8ffe7 JL |
4 | Contributed by John Carr (jfc@mit.edu). |
5 | ||
1322177d | 6 | This file is part of GCC. |
9ae8ffe7 | 7 | |
1322177d LB |
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 | |
9dcd6f09 | 10 | Software Foundation; either version 3, or (at your option) any later |
1322177d | 11 | version. |
9ae8ffe7 | 12 | |
1322177d LB |
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. | |
9ae8ffe7 JL |
17 | |
18 | You should have received a copy of the GNU General Public License | |
9dcd6f09 NC |
19 | along with GCC; see the file COPYING3. If not see |
20 | <http://www.gnu.org/licenses/>. */ | |
9ae8ffe7 JL |
21 | |
22 | #include "config.h" | |
670ee920 | 23 | #include "system.h" |
4977bab6 ZW |
24 | #include "coretypes.h" |
25 | #include "tm.h" | |
9ae8ffe7 | 26 | #include "rtl.h" |
7790df19 | 27 | #include "tree.h" |
6baf1cc8 | 28 | #include "tm_p.h" |
49ad7cfa | 29 | #include "function.h" |
78528714 JQ |
30 | #include "alias.h" |
31 | #include "emit-rtl.h" | |
9ae8ffe7 JL |
32 | #include "regs.h" |
33 | #include "hard-reg-set.h" | |
e004f2f7 | 34 | #include "basic-block.h" |
9ae8ffe7 | 35 | #include "flags.h" |
264fac34 | 36 | #include "output.h" |
2e107e9e | 37 | #include "toplev.h" |
eab5c70a | 38 | #include "cselib.h" |
3932261a | 39 | #include "splay-tree.h" |
ac606739 | 40 | #include "ggc.h" |
d23c55c2 | 41 | #include "langhooks.h" |
0d446150 | 42 | #include "timevar.h" |
ab780373 | 43 | #include "target.h" |
b255a036 | 44 | #include "cgraph.h" |
9ddb66ca | 45 | #include "varray.h" |
ef330312 | 46 | #include "tree-pass.h" |
ea900239 | 47 | #include "ipa-type-escape.h" |
6fb5fa3c | 48 | #include "df.h" |
55b34b5f RG |
49 | #include "tree-ssa-alias.h" |
50 | #include "pointer-set.h" | |
51 | #include "tree-flow.h" | |
ea900239 DB |
52 | |
53 | /* The aliasing API provided here solves related but different problems: | |
54 | ||
c22cacf3 | 55 | Say there exists (in c) |
ea900239 DB |
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 | |
c22cacf3 | 93 | instances do not escape across the compilation boundary. |
ea900239 DB |
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 | */ | |
3932261a MM |
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 | |
ac3d9668 RK |
106 | different alias sets cannot alias each other, with one important |
107 | exception. Consider something like: | |
3932261a | 108 | |
01d28c3f | 109 | struct S { int i; double d; }; |
3932261a MM |
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: | |
c22cacf3 MS |
115 | struct S |
116 | / \ | |
3932261a | 117 | / \ |
c22cacf3 MS |
118 | |/_ _\| |
119 | int double | |
3932261a | 120 | |
ac3d9668 RK |
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 | ||
3bdf5ad1 RK |
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 | |
95bd1dd7 | 127 | past immediate descendants, however, since we propagate all |
3bdf5ad1 | 128 | grandchildren up one level. |
3932261a MM |
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 | ||
7e5487a2 | 134 | struct GTY(()) alias_set_entry_d { |
3932261a | 135 | /* The alias set number, as stored in MEM_ALIAS_SET. */ |
4862826d | 136 | alias_set_type alias_set; |
3932261a | 137 | |
4c067742 RG |
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 | ||
3932261a | 142 | /* The children of the alias set. These are not just the immediate |
95bd1dd7 | 143 | children, but, in fact, all descendants. So, if we have: |
3932261a | 144 | |
ca7fd9cd | 145 | struct T { struct S s; float f; } |
3932261a MM |
146 | |
147 | continuing our example above, the children here will be all of | |
148 | `int', `double', `float', and `struct S'. */ | |
b604074c | 149 | splay_tree GTY((param1_is (int), param2_is (int))) children; |
b604074c | 150 | }; |
7e5487a2 | 151 | typedef struct alias_set_entry_d *alias_set_entry; |
9ae8ffe7 | 152 | |
ed7a4b4b | 153 | static int rtx_equal_for_memref_p (const_rtx, const_rtx); |
4682ae04 | 154 | static int memrefs_conflict_p (int, rtx, int, rtx, HOST_WIDE_INT); |
7bc980e1 | 155 | static void record_set (rtx, const_rtx, void *); |
4682ae04 AJ |
156 | static int base_alias_check (rtx, rtx, enum machine_mode, |
157 | enum machine_mode); | |
158 | static rtx find_base_value (rtx); | |
4f588890 | 159 | static int mems_in_disjoint_alias_sets_p (const_rtx, const_rtx); |
4682ae04 | 160 | static int insert_subset_children (splay_tree_node, void*); |
4862826d | 161 | static alias_set_entry get_alias_set_entry (alias_set_type); |
4f588890 KG |
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); | |
4682ae04 AJ |
166 | static tree decl_for_component_ref (tree); |
167 | static rtx adjust_offset_for_component_ref (tree, rtx); | |
4f588890 | 168 | static int write_dependence_p (const_rtx, const_rtx, int); |
4682ae04 | 169 | |
aa317c97 | 170 | static void memory_modified_1 (rtx, const_rtx, void *); |
9ae8ffe7 JL |
171 | |
172 | /* Set up all info needed to perform alias analysis on memory references. */ | |
173 | ||
d4b60170 | 174 | /* Returns the size in bytes of the mode of X. */ |
9ae8ffe7 JL |
175 | #define SIZE_FOR_MODE(X) (GET_MODE_SIZE (GET_MODE (X))) |
176 | ||
41472af8 | 177 | /* Returns nonzero if MEM1 and MEM2 do not alias because they are in |
264fac34 MM |
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) \ | |
3932261a | 182 | mems_in_disjoint_alias_sets_p (MEM1, MEM2) |
41472af8 | 183 | |
ea64ef27 | 184 | /* Cap the number of passes we make over the insns propagating alias |
ac3d9668 | 185 | information through set chains. 10 is a completely arbitrary choice. */ |
ea64ef27 | 186 | #define MAX_ALIAS_LOOP_PASSES 10 |
ca7fd9cd | 187 | |
9ae8ffe7 JL |
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 | |
2a2c8203 JC |
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 | |
ca7fd9cd | 196 | the stack, frame, and argument pointers. |
b3b5ad95 JL |
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. */ | |
2a2c8203 | 206 | |
08c79682 | 207 | static GTY(()) VEC(rtx,gc) *reg_base_value; |
ac606739 | 208 | static rtx *new_reg_base_value; |
c582d54a JH |
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. */ | |
08c79682 | 213 | static GTY((deletable)) VEC(rtx,gc) *old_reg_base_value; |
d4b60170 | 214 | |
bf1660a6 JL |
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 | ||
08c79682 KH |
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) | |
9ae8ffe7 | 222 | |
c13e8210 | 223 | /* Vector indexed by N giving the initial (unchanging) value known for |
bb1acb3e RH |
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; | |
9ae8ffe7 JL |
227 | |
228 | /* Indicates number of valid entries in reg_known_value. */ | |
bb1acb3e | 229 | static GTY(()) unsigned int reg_known_value_size; |
9ae8ffe7 JL |
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 | |
ac3d9668 RK |
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. */ | |
bb1acb3e | 243 | static bool *reg_known_equiv_p; |
9ae8ffe7 | 244 | |
2a2c8203 JC |
245 | /* True when scanning insns from the start of the rtl to the |
246 | NOTE_INSN_FUNCTION_BEG note. */ | |
83bbd9b6 | 247 | static bool copying_arguments; |
9ae8ffe7 | 248 | |
1a5640b4 KH |
249 | DEF_VEC_P(alias_set_entry); |
250 | DEF_VEC_ALLOC_P(alias_set_entry,gc); | |
251 | ||
3932261a | 252 | /* The splay-tree used to store the various alias set entries. */ |
1a5640b4 | 253 | static GTY (()) VEC(alias_set_entry,gc) *alias_sets; |
ac3d9668 | 254 | \f |
55b34b5f RG |
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 | ||
b0e96404 RG |
268 | /* If MEM_OFFSET or MEM_SIZE are NULL punt. */ |
269 | if (!MEM_OFFSET (mem) | |
270 | || !MEM_SIZE (mem)) | |
271 | return false; | |
272 | ||
55b34b5f RG |
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 | ||
c9b2f286 RG |
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 | ||
55b34b5f RG |
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 | ||
b0e96404 RG |
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; | |
55b34b5f RG |
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 | ||
3932261a MM |
356 | /* Returns a pointer to the alias set entry for ALIAS_SET, if there is |
357 | such an entry, or NULL otherwise. */ | |
358 | ||
9ddb66ca | 359 | static inline alias_set_entry |
4862826d | 360 | get_alias_set_entry (alias_set_type alias_set) |
3932261a | 361 | { |
1a5640b4 | 362 | return VEC_index (alias_set_entry, alias_sets, alias_set); |
3932261a MM |
363 | } |
364 | ||
ac3d9668 RK |
365 | /* Returns nonzero if the alias sets for MEM1 and MEM2 are such that |
366 | the two MEMs cannot alias each other. */ | |
3932261a | 367 | |
9ddb66ca | 368 | static inline int |
4f588890 | 369 | mems_in_disjoint_alias_sets_p (const_rtx mem1, const_rtx mem2) |
3932261a | 370 | { |
3932261a MM |
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. */ | |
298e6adc NS |
378 | gcc_assert (flag_strict_aliasing |
379 | || (!MEM_ALIAS_SET (mem1) && !MEM_ALIAS_SET (mem2))); | |
3932261a | 380 | |
1da68f56 RK |
381 | return ! alias_sets_conflict_p (MEM_ALIAS_SET (mem1), MEM_ALIAS_SET (mem2)); |
382 | } | |
3932261a | 383 | |
1da68f56 RK |
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 | |
4682ae04 | 388 | insert_subset_children (splay_tree_node node, void *data) |
1da68f56 RK |
389 | { |
390 | splay_tree_insert ((splay_tree) data, node->key, node->value); | |
391 | ||
392 | return 0; | |
393 | } | |
394 | ||
c58936b6 DB |
395 | /* Return true if the first alias set is a subset of the second. */ |
396 | ||
397 | bool | |
4862826d | 398 | alias_set_subset_of (alias_set_type set1, alias_set_type set2) |
c58936b6 DB |
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 | |
a7a512be RG |
409 | && ((ase->has_zero_child && set1 == 0) |
410 | || splay_tree_lookup (ase->children, | |
411 | (splay_tree_key) set1))) | |
c58936b6 DB |
412 | return true; |
413 | return false; | |
414 | } | |
415 | ||
1da68f56 RK |
416 | /* Return 1 if the two specified alias sets may conflict. */ |
417 | ||
418 | int | |
4862826d | 419 | alias_sets_conflict_p (alias_set_type set1, alias_set_type set2) |
1da68f56 RK |
420 | { |
421 | alias_set_entry ase; | |
422 | ||
836f7794 EB |
423 | /* The easy case. */ |
424 | if (alias_sets_must_conflict_p (set1, set2)) | |
1da68f56 | 425 | return 1; |
3932261a | 426 | |
3bdf5ad1 | 427 | /* See if the first alias set is a subset of the second. */ |
1da68f56 | 428 | ase = get_alias_set_entry (set1); |
2bf105ab RK |
429 | if (ase != 0 |
430 | && (ase->has_zero_child | |
431 | || splay_tree_lookup (ase->children, | |
1da68f56 RK |
432 | (splay_tree_key) set2))) |
433 | return 1; | |
3932261a MM |
434 | |
435 | /* Now do the same, but with the alias sets reversed. */ | |
1da68f56 | 436 | ase = get_alias_set_entry (set2); |
2bf105ab RK |
437 | if (ase != 0 |
438 | && (ase->has_zero_child | |
439 | || splay_tree_lookup (ase->children, | |
1da68f56 RK |
440 | (splay_tree_key) set1))) |
441 | return 1; | |
3932261a | 442 | |
1da68f56 | 443 | /* The two alias sets are distinct and neither one is the |
836f7794 | 444 | child of the other. Therefore, they cannot conflict. */ |
1da68f56 | 445 | return 0; |
3932261a | 446 | } |
5399d643 | 447 | |
71a6fe66 BM |
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 | ||
836f7794 | 485 | /* Return 1 if the two specified alias sets will always conflict. */ |
5399d643 JW |
486 | |
487 | int | |
4862826d | 488 | alias_sets_must_conflict_p (alias_set_type set1, alias_set_type set2) |
5399d643 JW |
489 | { |
490 | if (set1 == 0 || set2 == 0 || set1 == set2) | |
491 | return 1; | |
492 | ||
493 | return 0; | |
494 | } | |
495 | ||
1da68f56 RK |
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 | |
4682ae04 | 502 | objects_must_conflict_p (tree t1, tree t2) |
1da68f56 | 503 | { |
4862826d | 504 | alias_set_type set1, set2; |
82d610ec | 505 | |
e8ea2809 RK |
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. */ | |
981a4c34 | 509 | if (t1 == 0 && t2 == 0) |
e8ea2809 RK |
510 | return 0; |
511 | ||
1da68f56 RK |
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 | ||
82d610ec RK |
518 | set1 = t1 ? get_alias_set (t1) : 0; |
519 | set2 = t2 ? get_alias_set (t2) : 0; | |
1da68f56 | 520 | |
836f7794 EB |
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 | |
82d610ec RK |
523 | t2 for which a pair of subobjects of these respective subtypes |
524 | overlaps on the stack. */ | |
836f7794 | 525 | return alias_sets_must_conflict_p (set1, set2); |
1da68f56 RK |
526 | } |
527 | \f | |
2039d7aa RH |
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 | |
22ea9ec0 | 539 | component_uses_parent_alias_set (const_tree t) |
6e24b709 | 540 | { |
afe84921 RH |
541 | while (1) |
542 | { | |
2039d7aa | 543 | /* If we're at the end, it vacuously uses its own alias set. */ |
afe84921 | 544 | if (!handled_component_p (t)) |
2039d7aa | 545 | return false; |
afe84921 RH |
546 | |
547 | switch (TREE_CODE (t)) | |
548 | { | |
549 | case COMPONENT_REF: | |
550 | if (DECL_NONADDRESSABLE_P (TREE_OPERAND (t, 1))) | |
2039d7aa | 551 | return true; |
afe84921 RH |
552 | break; |
553 | ||
554 | case ARRAY_REF: | |
555 | case ARRAY_RANGE_REF: | |
556 | if (TYPE_NONALIASED_COMPONENT (TREE_TYPE (TREE_OPERAND (t, 0)))) | |
2039d7aa | 557 | return true; |
afe84921 RH |
558 | break; |
559 | ||
560 | case REALPART_EXPR: | |
561 | case IMAGPART_EXPR: | |
562 | break; | |
563 | ||
564 | default: | |
565 | /* Bitfields and casts are never addressable. */ | |
2039d7aa | 566 | return true; |
afe84921 RH |
567 | } |
568 | ||
569 | t = TREE_OPERAND (t, 0); | |
2039d7aa RH |
570 | if (get_alias_set (TREE_TYPE (t)) == 0) |
571 | return true; | |
afe84921 | 572 | } |
6e24b709 RK |
573 | } |
574 | ||
5006671f RG |
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 | ||
5b21f0f3 | 587 | /* All we care about is the type. */ |
5006671f | 588 | if (! TYPE_P (t)) |
5b21f0f3 | 589 | t = TREE_TYPE (t); |
5006671f RG |
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 | ||
3bdf5ad1 RK |
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 | ||
4862826d | 623 | alias_set_type |
4682ae04 | 624 | get_alias_set (tree t) |
3bdf5ad1 | 625 | { |
4862826d | 626 | alias_set_type set; |
3bdf5ad1 RK |
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 | |
f47e9b4e RK |
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 | |
738cc472 | 640 | aren't types. */ |
f824e5c3 | 641 | if (! TYPE_P (t)) |
3bdf5ad1 | 642 | { |
738cc472 | 643 | tree inner = t; |
738cc472 | 644 | |
8ac61af7 RK |
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); | |
ae2bcd98 | 648 | set = lang_hooks.get_alias_set (t); |
8ac61af7 RK |
649 | if (set != -1) |
650 | return set; | |
651 | ||
738cc472 | 652 | /* First see if the actual object referenced is an INDIRECT_REF from a |
6fce44af RK |
653 | restrict-qualified pointer or a "void *". */ |
654 | while (handled_component_p (inner)) | |
738cc472 | 655 | { |
6fce44af | 656 | inner = TREE_OPERAND (inner, 0); |
8ac61af7 | 657 | STRIP_NOPS (inner); |
738cc472 RK |
658 | } |
659 | ||
1b096a0a | 660 | if (INDIRECT_REF_P (inner)) |
738cc472 | 661 | { |
5006671f RG |
662 | set = get_deref_alias_set_1 (TREE_OPERAND (inner, 0)); |
663 | if (set != -1) | |
664 | return set; | |
738cc472 RK |
665 | } |
666 | ||
667 | /* Otherwise, pick up the outermost object that we could have a pointer | |
6fce44af | 668 | to, processing conversions as above. */ |
2039d7aa | 669 | while (component_uses_parent_alias_set (t)) |
f47e9b4e | 670 | { |
6fce44af | 671 | t = TREE_OPERAND (t, 0); |
8ac61af7 RK |
672 | STRIP_NOPS (t); |
673 | } | |
f824e5c3 | 674 | |
738cc472 RK |
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!). */ | |
5755cd38 | 678 | if (TREE_CODE (t) == VAR_DECL |
3c0cb5de | 679 | && DECL_RTL_SET_P (t) && MEM_P (DECL_RTL (t))) |
5755cd38 JM |
680 | return MEM_ALIAS_SET (DECL_RTL (t)); |
681 | ||
f824e5c3 RK |
682 | /* Now all we care about is the type. */ |
683 | t = TREE_TYPE (t); | |
3bdf5ad1 RK |
684 | } |
685 | ||
3bdf5ad1 | 686 | /* Variant qualifiers don't affect the alias set, so get the main |
daad0278 | 687 | variant. */ |
3bdf5ad1 | 688 | t = TYPE_MAIN_VARIANT (t); |
daad0278 RG |
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)) | |
694 | return 0; | |
695 | t = TYPE_CANONICAL (t); | |
696 | /* Canonical types shouldn't form a tree nor should the canonical | |
697 | type require structural equality checks. */ | |
698 | gcc_assert (!TYPE_STRUCTURAL_EQUALITY_P (t) && TYPE_CANONICAL (t) == t); | |
699 | ||
700 | /* If this is a type with a known alias set, return it. */ | |
738cc472 | 701 | if (TYPE_ALIAS_SET_KNOWN_P (t)) |
3bdf5ad1 RK |
702 | return TYPE_ALIAS_SET (t); |
703 | ||
36784d0e RG |
704 | /* We don't want to set TYPE_ALIAS_SET for incomplete types. */ |
705 | if (!COMPLETE_TYPE_P (t)) | |
706 | { | |
707 | /* For arrays with unknown size the conservative answer is the | |
708 | alias set of the element type. */ | |
709 | if (TREE_CODE (t) == ARRAY_TYPE) | |
710 | return get_alias_set (TREE_TYPE (t)); | |
711 | ||
712 | /* But return zero as a conservative answer for incomplete types. */ | |
713 | return 0; | |
714 | } | |
715 | ||
3bdf5ad1 | 716 | /* See if the language has special handling for this type. */ |
ae2bcd98 | 717 | set = lang_hooks.get_alias_set (t); |
8ac61af7 | 718 | if (set != -1) |
738cc472 | 719 | return set; |
2bf105ab | 720 | |
3bdf5ad1 RK |
721 | /* There are no objects of FUNCTION_TYPE, so there's no point in |
722 | using up an alias set for them. (There are, of course, pointers | |
723 | and references to functions, but that's different.) */ | |
e11e491d RG |
724 | else if (TREE_CODE (t) == FUNCTION_TYPE |
725 | || TREE_CODE (t) == METHOD_TYPE) | |
3bdf5ad1 | 726 | set = 0; |
74d86f4f RH |
727 | |
728 | /* Unless the language specifies otherwise, let vector types alias | |
729 | their components. This avoids some nasty type punning issues in | |
730 | normal usage. And indeed lets vectors be treated more like an | |
731 | array slice. */ | |
732 | else if (TREE_CODE (t) == VECTOR_TYPE) | |
733 | set = get_alias_set (TREE_TYPE (t)); | |
734 | ||
4653cae5 RG |
735 | /* Unless the language specifies otherwise, treat array types the |
736 | same as their components. This avoids the asymmetry we get | |
737 | through recording the components. Consider accessing a | |
738 | character(kind=1) through a reference to a character(kind=1)[1:1]. | |
739 | Or consider if we want to assign integer(kind=4)[0:D.1387] and | |
740 | integer(kind=4)[4] the same alias set or not. | |
741 | Just be pragmatic here and make sure the array and its element | |
742 | type get the same alias set assigned. */ | |
743 | else if (TREE_CODE (t) == ARRAY_TYPE | |
744 | && !TYPE_NONALIASED_COMPONENT (t)) | |
745 | set = get_alias_set (TREE_TYPE (t)); | |
746 | ||
3bdf5ad1 RK |
747 | else |
748 | /* Otherwise make a new alias set for this type. */ | |
749 | set = new_alias_set (); | |
750 | ||
751 | TYPE_ALIAS_SET (t) = set; | |
2bf105ab RK |
752 | |
753 | /* If this is an aggregate type, we must record any component aliasing | |
754 | information. */ | |
1d79fd2c | 755 | if (AGGREGATE_TYPE_P (t) || TREE_CODE (t) == COMPLEX_TYPE) |
2bf105ab RK |
756 | record_component_aliases (t); |
757 | ||
3bdf5ad1 RK |
758 | return set; |
759 | } | |
760 | ||
761 | /* Return a brand-new alias set. */ | |
762 | ||
4862826d | 763 | alias_set_type |
4682ae04 | 764 | new_alias_set (void) |
3bdf5ad1 | 765 | { |
3bdf5ad1 | 766 | if (flag_strict_aliasing) |
9ddb66ca | 767 | { |
1a5640b4 KH |
768 | if (alias_sets == 0) |
769 | VEC_safe_push (alias_set_entry, gc, alias_sets, 0); | |
770 | VEC_safe_push (alias_set_entry, gc, alias_sets, 0); | |
771 | return VEC_length (alias_set_entry, alias_sets) - 1; | |
9ddb66ca | 772 | } |
3bdf5ad1 RK |
773 | else |
774 | return 0; | |
775 | } | |
3932261a | 776 | |
01d28c3f JM |
777 | /* Indicate that things in SUBSET can alias things in SUPERSET, but that |
778 | not everything that aliases SUPERSET also aliases SUBSET. For example, | |
779 | in C, a store to an `int' can alias a load of a structure containing an | |
780 | `int', and vice versa. But it can't alias a load of a 'double' member | |
781 | of the same structure. Here, the structure would be the SUPERSET and | |
782 | `int' the SUBSET. This relationship is also described in the comment at | |
783 | the beginning of this file. | |
784 | ||
785 | This function should be called only once per SUPERSET/SUBSET pair. | |
3932261a MM |
786 | |
787 | It is illegal for SUPERSET to be zero; everything is implicitly a | |
788 | subset of alias set zero. */ | |
789 | ||
794511d2 | 790 | void |
4862826d | 791 | record_alias_subset (alias_set_type superset, alias_set_type subset) |
3932261a MM |
792 | { |
793 | alias_set_entry superset_entry; | |
794 | alias_set_entry subset_entry; | |
795 | ||
f47e9b4e RK |
796 | /* It is possible in complex type situations for both sets to be the same, |
797 | in which case we can ignore this operation. */ | |
798 | if (superset == subset) | |
799 | return; | |
800 | ||
298e6adc | 801 | gcc_assert (superset); |
3932261a MM |
802 | |
803 | superset_entry = get_alias_set_entry (superset); | |
ca7fd9cd | 804 | if (superset_entry == 0) |
3932261a MM |
805 | { |
806 | /* Create an entry for the SUPERSET, so that we have a place to | |
807 | attach the SUBSET. */ | |
7e5487a2 | 808 | superset_entry = GGC_NEW (struct alias_set_entry_d); |
3932261a | 809 | superset_entry->alias_set = superset; |
ca7fd9cd | 810 | superset_entry->children |
b604074c | 811 | = splay_tree_new_ggc (splay_tree_compare_ints); |
570eb5c8 | 812 | superset_entry->has_zero_child = 0; |
1a5640b4 | 813 | VEC_replace (alias_set_entry, alias_sets, superset, superset_entry); |
3932261a MM |
814 | } |
815 | ||
2bf105ab RK |
816 | if (subset == 0) |
817 | superset_entry->has_zero_child = 1; | |
818 | else | |
819 | { | |
820 | subset_entry = get_alias_set_entry (subset); | |
821 | /* If there is an entry for the subset, enter all of its children | |
822 | (if they are not already present) as children of the SUPERSET. */ | |
ca7fd9cd | 823 | if (subset_entry) |
2bf105ab RK |
824 | { |
825 | if (subset_entry->has_zero_child) | |
826 | superset_entry->has_zero_child = 1; | |
d4b60170 | 827 | |
2bf105ab RK |
828 | splay_tree_foreach (subset_entry->children, insert_subset_children, |
829 | superset_entry->children); | |
830 | } | |
3932261a | 831 | |
2bf105ab | 832 | /* Enter the SUBSET itself as a child of the SUPERSET. */ |
ca7fd9cd | 833 | splay_tree_insert (superset_entry->children, |
2bf105ab RK |
834 | (splay_tree_key) subset, 0); |
835 | } | |
3932261a MM |
836 | } |
837 | ||
a0c33338 RK |
838 | /* Record that component types of TYPE, if any, are part of that type for |
839 | aliasing purposes. For record types, we only record component types | |
b5487346 EB |
840 | for fields that are not marked non-addressable. For array types, we |
841 | only record the component type if it is not marked non-aliased. */ | |
a0c33338 RK |
842 | |
843 | void | |
4682ae04 | 844 | record_component_aliases (tree type) |
a0c33338 | 845 | { |
4862826d | 846 | alias_set_type superset = get_alias_set (type); |
a0c33338 RK |
847 | tree field; |
848 | ||
849 | if (superset == 0) | |
850 | return; | |
851 | ||
852 | switch (TREE_CODE (type)) | |
853 | { | |
a0c33338 RK |
854 | case RECORD_TYPE: |
855 | case UNION_TYPE: | |
856 | case QUAL_UNION_TYPE: | |
6614fd40 | 857 | /* Recursively record aliases for the base classes, if there are any. */ |
fa743e8c | 858 | if (TYPE_BINFO (type)) |
ca7fd9cd KH |
859 | { |
860 | int i; | |
fa743e8c | 861 | tree binfo, base_binfo; |
c22cacf3 | 862 | |
fa743e8c NS |
863 | for (binfo = TYPE_BINFO (type), i = 0; |
864 | BINFO_BASE_ITERATE (binfo, i, base_binfo); i++) | |
865 | record_alias_subset (superset, | |
866 | get_alias_set (BINFO_TYPE (base_binfo))); | |
ca7fd9cd | 867 | } |
a0c33338 | 868 | for (field = TYPE_FIELDS (type); field != 0; field = TREE_CHAIN (field)) |
b5487346 | 869 | if (TREE_CODE (field) == FIELD_DECL && !DECL_NONADDRESSABLE_P (field)) |
2bf105ab | 870 | record_alias_subset (superset, get_alias_set (TREE_TYPE (field))); |
a0c33338 RK |
871 | break; |
872 | ||
1d79fd2c JW |
873 | case COMPLEX_TYPE: |
874 | record_alias_subset (superset, get_alias_set (TREE_TYPE (type))); | |
875 | break; | |
876 | ||
4653cae5 RG |
877 | /* VECTOR_TYPE and ARRAY_TYPE share the alias set with their |
878 | element type. */ | |
879 | ||
a0c33338 RK |
880 | default: |
881 | break; | |
882 | } | |
883 | } | |
884 | ||
3bdf5ad1 RK |
885 | /* Allocate an alias set for use in storing and reading from the varargs |
886 | spill area. */ | |
887 | ||
4862826d | 888 | static GTY(()) alias_set_type varargs_set = -1; |
f103e34d | 889 | |
4862826d | 890 | alias_set_type |
4682ae04 | 891 | get_varargs_alias_set (void) |
3bdf5ad1 | 892 | { |
cd3ce9b4 JM |
893 | #if 1 |
894 | /* We now lower VA_ARG_EXPR, and there's currently no way to attach the | |
895 | varargs alias set to an INDIRECT_REF (FIXME!), so we can't | |
896 | consistently use the varargs alias set for loads from the varargs | |
897 | area. So don't use it anywhere. */ | |
898 | return 0; | |
899 | #else | |
f103e34d GK |
900 | if (varargs_set == -1) |
901 | varargs_set = new_alias_set (); | |
3bdf5ad1 | 902 | |
f103e34d | 903 | return varargs_set; |
cd3ce9b4 | 904 | #endif |
3bdf5ad1 RK |
905 | } |
906 | ||
907 | /* Likewise, but used for the fixed portions of the frame, e.g., register | |
908 | save areas. */ | |
909 | ||
4862826d | 910 | static GTY(()) alias_set_type frame_set = -1; |
f103e34d | 911 | |
4862826d | 912 | alias_set_type |
4682ae04 | 913 | get_frame_alias_set (void) |
3bdf5ad1 | 914 | { |
f103e34d GK |
915 | if (frame_set == -1) |
916 | frame_set = new_alias_set (); | |
3bdf5ad1 | 917 | |
f103e34d | 918 | return frame_set; |
3bdf5ad1 RK |
919 | } |
920 | ||
2a2c8203 JC |
921 | /* Inside SRC, the source of a SET, find a base address. */ |
922 | ||
9ae8ffe7 | 923 | static rtx |
4682ae04 | 924 | find_base_value (rtx src) |
9ae8ffe7 | 925 | { |
713f41f9 | 926 | unsigned int regno; |
0aacc8ed | 927 | |
53451050 RS |
928 | #if defined (FIND_BASE_TERM) |
929 | /* Try machine-dependent ways to find the base term. */ | |
930 | src = FIND_BASE_TERM (src); | |
931 | #endif | |
932 | ||
9ae8ffe7 JL |
933 | switch (GET_CODE (src)) |
934 | { | |
935 | case SYMBOL_REF: | |
936 | case LABEL_REF: | |
937 | return src; | |
938 | ||
939 | case REG: | |
fb6754f0 | 940 | regno = REGNO (src); |
d4b60170 | 941 | /* At the start of a function, argument registers have known base |
2a2c8203 JC |
942 | values which may be lost later. Returning an ADDRESS |
943 | expression here allows optimization based on argument values | |
944 | even when the argument registers are used for other purposes. */ | |
713f41f9 BS |
945 | if (regno < FIRST_PSEUDO_REGISTER && copying_arguments) |
946 | return new_reg_base_value[regno]; | |
73774bc7 | 947 | |
eaf407a5 | 948 | /* If a pseudo has a known base value, return it. Do not do this |
9b462c42 RH |
949 | for non-fixed hard regs since it can result in a circular |
950 | dependency chain for registers which have values at function entry. | |
eaf407a5 JL |
951 | |
952 | The test above is not sufficient because the scheduler may move | |
953 | a copy out of an arg reg past the NOTE_INSN_FUNCTION_BEGIN. */ | |
9b462c42 | 954 | if ((regno >= FIRST_PSEUDO_REGISTER || fixed_regs[regno]) |
08c79682 | 955 | && regno < VEC_length (rtx, reg_base_value)) |
83bbd9b6 RH |
956 | { |
957 | /* If we're inside init_alias_analysis, use new_reg_base_value | |
958 | to reduce the number of relaxation iterations. */ | |
1afdf91c | 959 | if (new_reg_base_value && new_reg_base_value[regno] |
6fb5fa3c | 960 | && DF_REG_DEF_COUNT (regno) == 1) |
83bbd9b6 RH |
961 | return new_reg_base_value[regno]; |
962 | ||
08c79682 KH |
963 | if (VEC_index (rtx, reg_base_value, regno)) |
964 | return VEC_index (rtx, reg_base_value, regno); | |
83bbd9b6 | 965 | } |
73774bc7 | 966 | |
e3f049a8 | 967 | return 0; |
9ae8ffe7 JL |
968 | |
969 | case MEM: | |
970 | /* Check for an argument passed in memory. Only record in the | |
971 | copying-arguments block; it is too hard to track changes | |
972 | otherwise. */ | |
973 | if (copying_arguments | |
974 | && (XEXP (src, 0) == arg_pointer_rtx | |
975 | || (GET_CODE (XEXP (src, 0)) == PLUS | |
976 | && XEXP (XEXP (src, 0), 0) == arg_pointer_rtx))) | |
38a448ca | 977 | return gen_rtx_ADDRESS (VOIDmode, src); |
9ae8ffe7 JL |
978 | return 0; |
979 | ||
980 | case CONST: | |
981 | src = XEXP (src, 0); | |
982 | if (GET_CODE (src) != PLUS && GET_CODE (src) != MINUS) | |
983 | break; | |
d4b60170 | 984 | |
ec5c56db | 985 | /* ... fall through ... */ |
2a2c8203 | 986 | |
9ae8ffe7 JL |
987 | case PLUS: |
988 | case MINUS: | |
2a2c8203 | 989 | { |
ec907dd8 JL |
990 | rtx temp, src_0 = XEXP (src, 0), src_1 = XEXP (src, 1); |
991 | ||
0134bf2d DE |
992 | /* If either operand is a REG that is a known pointer, then it |
993 | is the base. */ | |
994 | if (REG_P (src_0) && REG_POINTER (src_0)) | |
995 | return find_base_value (src_0); | |
996 | if (REG_P (src_1) && REG_POINTER (src_1)) | |
997 | return find_base_value (src_1); | |
998 | ||
ec907dd8 JL |
999 | /* If either operand is a REG, then see if we already have |
1000 | a known value for it. */ | |
0134bf2d | 1001 | if (REG_P (src_0)) |
ec907dd8 JL |
1002 | { |
1003 | temp = find_base_value (src_0); | |
d4b60170 | 1004 | if (temp != 0) |
ec907dd8 JL |
1005 | src_0 = temp; |
1006 | } | |
1007 | ||
0134bf2d | 1008 | if (REG_P (src_1)) |
ec907dd8 JL |
1009 | { |
1010 | temp = find_base_value (src_1); | |
d4b60170 | 1011 | if (temp!= 0) |
ec907dd8 JL |
1012 | src_1 = temp; |
1013 | } | |
2a2c8203 | 1014 | |
0134bf2d DE |
1015 | /* If either base is named object or a special address |
1016 | (like an argument or stack reference), then use it for the | |
1017 | base term. */ | |
1018 | if (src_0 != 0 | |
1019 | && (GET_CODE (src_0) == SYMBOL_REF | |
1020 | || GET_CODE (src_0) == LABEL_REF | |
1021 | || (GET_CODE (src_0) == ADDRESS | |
1022 | && GET_MODE (src_0) != VOIDmode))) | |
1023 | return src_0; | |
1024 | ||
1025 | if (src_1 != 0 | |
1026 | && (GET_CODE (src_1) == SYMBOL_REF | |
1027 | || GET_CODE (src_1) == LABEL_REF | |
1028 | || (GET_CODE (src_1) == ADDRESS | |
1029 | && GET_MODE (src_1) != VOIDmode))) | |
1030 | return src_1; | |
1031 | ||
d4b60170 | 1032 | /* Guess which operand is the base address: |
ec907dd8 JL |
1033 | If either operand is a symbol, then it is the base. If |
1034 | either operand is a CONST_INT, then the other is the base. */ | |
481683e1 | 1035 | if (CONST_INT_P (src_1) || CONSTANT_P (src_0)) |
2a2c8203 | 1036 | return find_base_value (src_0); |
481683e1 | 1037 | else if (CONST_INT_P (src_0) || CONSTANT_P (src_1)) |
ec907dd8 JL |
1038 | return find_base_value (src_1); |
1039 | ||
9ae8ffe7 | 1040 | return 0; |
2a2c8203 JC |
1041 | } |
1042 | ||
1043 | case LO_SUM: | |
1044 | /* The standard form is (lo_sum reg sym) so look only at the | |
1045 | second operand. */ | |
1046 | return find_base_value (XEXP (src, 1)); | |
9ae8ffe7 JL |
1047 | |
1048 | case AND: | |
1049 | /* If the second operand is constant set the base | |
ec5c56db | 1050 | address to the first operand. */ |
481683e1 | 1051 | if (CONST_INT_P (XEXP (src, 1)) && INTVAL (XEXP (src, 1)) != 0) |
2a2c8203 | 1052 | return find_base_value (XEXP (src, 0)); |
9ae8ffe7 JL |
1053 | return 0; |
1054 | ||
61f0131c R |
1055 | case TRUNCATE: |
1056 | if (GET_MODE_SIZE (GET_MODE (src)) < GET_MODE_SIZE (Pmode)) | |
1057 | break; | |
1058 | /* Fall through. */ | |
9ae8ffe7 | 1059 | case HIGH: |
d288e53d DE |
1060 | case PRE_INC: |
1061 | case PRE_DEC: | |
1062 | case POST_INC: | |
1063 | case POST_DEC: | |
1064 | case PRE_MODIFY: | |
1065 | case POST_MODIFY: | |
2a2c8203 | 1066 | return find_base_value (XEXP (src, 0)); |
1d300e19 | 1067 | |
0aacc8ed RK |
1068 | case ZERO_EXTEND: |
1069 | case SIGN_EXTEND: /* used for NT/Alpha pointers */ | |
1070 | { | |
1071 | rtx temp = find_base_value (XEXP (src, 0)); | |
1072 | ||
5ae6cd0d | 1073 | if (temp != 0 && CONSTANT_P (temp)) |
0aacc8ed | 1074 | temp = convert_memory_address (Pmode, temp); |
0aacc8ed RK |
1075 | |
1076 | return temp; | |
1077 | } | |
1078 | ||
1d300e19 KG |
1079 | default: |
1080 | break; | |
9ae8ffe7 JL |
1081 | } |
1082 | ||
1083 | return 0; | |
1084 | } | |
1085 | ||
1086 | /* Called from init_alias_analysis indirectly through note_stores. */ | |
1087 | ||
d4b60170 | 1088 | /* While scanning insns to find base values, reg_seen[N] is nonzero if |
9ae8ffe7 JL |
1089 | register N has been set in this function. */ |
1090 | static char *reg_seen; | |
1091 | ||
13309a5f JC |
1092 | /* Addresses which are known not to alias anything else are identified |
1093 | by a unique integer. */ | |
ec907dd8 JL |
1094 | static int unique_id; |
1095 | ||
2a2c8203 | 1096 | static void |
7bc980e1 | 1097 | record_set (rtx dest, const_rtx set, void *data ATTRIBUTE_UNUSED) |
9ae8ffe7 | 1098 | { |
b3694847 | 1099 | unsigned regno; |
9ae8ffe7 | 1100 | rtx src; |
c28b4e40 | 1101 | int n; |
9ae8ffe7 | 1102 | |
f8cfc6aa | 1103 | if (!REG_P (dest)) |
9ae8ffe7 JL |
1104 | return; |
1105 | ||
fb6754f0 | 1106 | regno = REGNO (dest); |
9ae8ffe7 | 1107 | |
08c79682 | 1108 | gcc_assert (regno < VEC_length (rtx, reg_base_value)); |
ac606739 | 1109 | |
c28b4e40 JW |
1110 | /* If this spans multiple hard registers, then we must indicate that every |
1111 | register has an unusable value. */ | |
1112 | if (regno < FIRST_PSEUDO_REGISTER) | |
66fd46b6 | 1113 | n = hard_regno_nregs[regno][GET_MODE (dest)]; |
c28b4e40 JW |
1114 | else |
1115 | n = 1; | |
1116 | if (n != 1) | |
1117 | { | |
1118 | while (--n >= 0) | |
1119 | { | |
1120 | reg_seen[regno + n] = 1; | |
1121 | new_reg_base_value[regno + n] = 0; | |
1122 | } | |
1123 | return; | |
1124 | } | |
1125 | ||
9ae8ffe7 JL |
1126 | if (set) |
1127 | { | |
1128 | /* A CLOBBER wipes out any old value but does not prevent a previously | |
1129 | unset register from acquiring a base address (i.e. reg_seen is not | |
1130 | set). */ | |
1131 | if (GET_CODE (set) == CLOBBER) | |
1132 | { | |
ec907dd8 | 1133 | new_reg_base_value[regno] = 0; |
9ae8ffe7 JL |
1134 | return; |
1135 | } | |
1136 | src = SET_SRC (set); | |
1137 | } | |
1138 | else | |
1139 | { | |
9ae8ffe7 JL |
1140 | if (reg_seen[regno]) |
1141 | { | |
ec907dd8 | 1142 | new_reg_base_value[regno] = 0; |
9ae8ffe7 JL |
1143 | return; |
1144 | } | |
1145 | reg_seen[regno] = 1; | |
38a448ca RH |
1146 | new_reg_base_value[regno] = gen_rtx_ADDRESS (Pmode, |
1147 | GEN_INT (unique_id++)); | |
9ae8ffe7 JL |
1148 | return; |
1149 | } | |
1150 | ||
5da6f168 RS |
1151 | /* If this is not the first set of REGNO, see whether the new value |
1152 | is related to the old one. There are two cases of interest: | |
1153 | ||
1154 | (1) The register might be assigned an entirely new value | |
1155 | that has the same base term as the original set. | |
1156 | ||
1157 | (2) The set might be a simple self-modification that | |
1158 | cannot change REGNO's base value. | |
1159 | ||
1160 | If neither case holds, reject the original base value as invalid. | |
1161 | Note that the following situation is not detected: | |
1162 | ||
c22cacf3 | 1163 | extern int x, y; int *p = &x; p += (&y-&x); |
5da6f168 | 1164 | |
9ae8ffe7 JL |
1165 | ANSI C does not allow computing the difference of addresses |
1166 | of distinct top level objects. */ | |
5da6f168 RS |
1167 | if (new_reg_base_value[regno] != 0 |
1168 | && find_base_value (src) != new_reg_base_value[regno]) | |
9ae8ffe7 JL |
1169 | switch (GET_CODE (src)) |
1170 | { | |
2a2c8203 | 1171 | case LO_SUM: |
9ae8ffe7 JL |
1172 | case MINUS: |
1173 | if (XEXP (src, 0) != dest && XEXP (src, 1) != dest) | |
ec907dd8 | 1174 | new_reg_base_value[regno] = 0; |
9ae8ffe7 | 1175 | break; |
61f0131c R |
1176 | case PLUS: |
1177 | /* If the value we add in the PLUS is also a valid base value, | |
1178 | this might be the actual base value, and the original value | |
1179 | an index. */ | |
1180 | { | |
1181 | rtx other = NULL_RTX; | |
1182 | ||
1183 | if (XEXP (src, 0) == dest) | |
1184 | other = XEXP (src, 1); | |
1185 | else if (XEXP (src, 1) == dest) | |
1186 | other = XEXP (src, 0); | |
1187 | ||
1188 | if (! other || find_base_value (other)) | |
1189 | new_reg_base_value[regno] = 0; | |
1190 | break; | |
1191 | } | |
9ae8ffe7 | 1192 | case AND: |
481683e1 | 1193 | if (XEXP (src, 0) != dest || !CONST_INT_P (XEXP (src, 1))) |
ec907dd8 | 1194 | new_reg_base_value[regno] = 0; |
9ae8ffe7 | 1195 | break; |
9ae8ffe7 | 1196 | default: |
ec907dd8 | 1197 | new_reg_base_value[regno] = 0; |
9ae8ffe7 JL |
1198 | break; |
1199 | } | |
1200 | /* If this is the first set of a register, record the value. */ | |
1201 | else if ((regno >= FIRST_PSEUDO_REGISTER || ! fixed_regs[regno]) | |
ec907dd8 JL |
1202 | && ! reg_seen[regno] && new_reg_base_value[regno] == 0) |
1203 | new_reg_base_value[regno] = find_base_value (src); | |
9ae8ffe7 JL |
1204 | |
1205 | reg_seen[regno] = 1; | |
1206 | } | |
1207 | ||
bb1acb3e RH |
1208 | /* If a value is known for REGNO, return it. */ |
1209 | ||
c22cacf3 | 1210 | rtx |
bb1acb3e RH |
1211 | get_reg_known_value (unsigned int regno) |
1212 | { | |
1213 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1214 | { | |
1215 | regno -= FIRST_PSEUDO_REGISTER; | |
1216 | if (regno < reg_known_value_size) | |
1217 | return reg_known_value[regno]; | |
1218 | } | |
1219 | return NULL; | |
43fe47ca JW |
1220 | } |
1221 | ||
bb1acb3e RH |
1222 | /* Set it. */ |
1223 | ||
1224 | static void | |
1225 | set_reg_known_value (unsigned int regno, rtx val) | |
1226 | { | |
1227 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1228 | { | |
1229 | regno -= FIRST_PSEUDO_REGISTER; | |
1230 | if (regno < reg_known_value_size) | |
1231 | reg_known_value[regno] = val; | |
1232 | } | |
1233 | } | |
1234 | ||
1235 | /* Similarly for reg_known_equiv_p. */ | |
1236 | ||
1237 | bool | |
1238 | get_reg_known_equiv_p (unsigned int regno) | |
1239 | { | |
1240 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1241 | { | |
1242 | regno -= FIRST_PSEUDO_REGISTER; | |
1243 | if (regno < reg_known_value_size) | |
1244 | return reg_known_equiv_p[regno]; | |
1245 | } | |
1246 | return false; | |
1247 | } | |
1248 | ||
1249 | static void | |
1250 | set_reg_known_equiv_p (unsigned int regno, bool val) | |
1251 | { | |
1252 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1253 | { | |
1254 | regno -= FIRST_PSEUDO_REGISTER; | |
1255 | if (regno < reg_known_value_size) | |
1256 | reg_known_equiv_p[regno] = val; | |
1257 | } | |
1258 | } | |
1259 | ||
1260 | ||
db048faf MM |
1261 | /* Returns a canonical version of X, from the point of view alias |
1262 | analysis. (For example, if X is a MEM whose address is a register, | |
1263 | and the register has a known value (say a SYMBOL_REF), then a MEM | |
1264 | whose address is the SYMBOL_REF is returned.) */ | |
1265 | ||
1266 | rtx | |
4682ae04 | 1267 | canon_rtx (rtx x) |
9ae8ffe7 JL |
1268 | { |
1269 | /* Recursively look for equivalences. */ | |
f8cfc6aa | 1270 | if (REG_P (x) && REGNO (x) >= FIRST_PSEUDO_REGISTER) |
bb1acb3e RH |
1271 | { |
1272 | rtx t = get_reg_known_value (REGNO (x)); | |
1273 | if (t == x) | |
1274 | return x; | |
1275 | if (t) | |
1276 | return canon_rtx (t); | |
1277 | } | |
1278 | ||
1279 | if (GET_CODE (x) == PLUS) | |
9ae8ffe7 JL |
1280 | { |
1281 | rtx x0 = canon_rtx (XEXP (x, 0)); | |
1282 | rtx x1 = canon_rtx (XEXP (x, 1)); | |
1283 | ||
1284 | if (x0 != XEXP (x, 0) || x1 != XEXP (x, 1)) | |
1285 | { | |
481683e1 | 1286 | if (CONST_INT_P (x0)) |
ed8908e7 | 1287 | return plus_constant (x1, INTVAL (x0)); |
481683e1 | 1288 | else if (CONST_INT_P (x1)) |
ed8908e7 | 1289 | return plus_constant (x0, INTVAL (x1)); |
38a448ca | 1290 | return gen_rtx_PLUS (GET_MODE (x), x0, x1); |
9ae8ffe7 JL |
1291 | } |
1292 | } | |
d4b60170 | 1293 | |
9ae8ffe7 JL |
1294 | /* This gives us much better alias analysis when called from |
1295 | the loop optimizer. Note we want to leave the original | |
1296 | MEM alone, but need to return the canonicalized MEM with | |
1297 | all the flags with their original values. */ | |
3c0cb5de | 1298 | else if (MEM_P (x)) |
f1ec5147 | 1299 | x = replace_equiv_address_nv (x, canon_rtx (XEXP (x, 0))); |
d4b60170 | 1300 | |
9ae8ffe7 JL |
1301 | return x; |
1302 | } | |
1303 | ||
1304 | /* Return 1 if X and Y are identical-looking rtx's. | |
45183e03 | 1305 | Expect that X and Y has been already canonicalized. |
9ae8ffe7 JL |
1306 | |
1307 | We use the data in reg_known_value above to see if two registers with | |
1308 | different numbers are, in fact, equivalent. */ | |
1309 | ||
1310 | static int | |
ed7a4b4b | 1311 | rtx_equal_for_memref_p (const_rtx x, const_rtx y) |
9ae8ffe7 | 1312 | { |
b3694847 SS |
1313 | int i; |
1314 | int j; | |
1315 | enum rtx_code code; | |
1316 | const char *fmt; | |
9ae8ffe7 JL |
1317 | |
1318 | if (x == 0 && y == 0) | |
1319 | return 1; | |
1320 | if (x == 0 || y == 0) | |
1321 | return 0; | |
d4b60170 | 1322 | |
9ae8ffe7 JL |
1323 | if (x == y) |
1324 | return 1; | |
1325 | ||
1326 | code = GET_CODE (x); | |
1327 | /* Rtx's of different codes cannot be equal. */ | |
1328 | if (code != GET_CODE (y)) | |
1329 | return 0; | |
1330 | ||
1331 | /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. | |
1332 | (REG:SI x) and (REG:HI x) are NOT equivalent. */ | |
1333 | ||
1334 | if (GET_MODE (x) != GET_MODE (y)) | |
1335 | return 0; | |
1336 | ||
db048faf MM |
1337 | /* Some RTL can be compared without a recursive examination. */ |
1338 | switch (code) | |
1339 | { | |
1340 | case REG: | |
1341 | return REGNO (x) == REGNO (y); | |
1342 | ||
1343 | case LABEL_REF: | |
1344 | return XEXP (x, 0) == XEXP (y, 0); | |
ca7fd9cd | 1345 | |
db048faf MM |
1346 | case SYMBOL_REF: |
1347 | return XSTR (x, 0) == XSTR (y, 0); | |
1348 | ||
40e02b4a | 1349 | case VALUE: |
db048faf MM |
1350 | case CONST_INT: |
1351 | case CONST_DOUBLE: | |
091a3ac7 | 1352 | case CONST_FIXED: |
db048faf MM |
1353 | /* There's no need to compare the contents of CONST_DOUBLEs or |
1354 | CONST_INTs because pointer equality is a good enough | |
1355 | comparison for these nodes. */ | |
1356 | return 0; | |
1357 | ||
db048faf MM |
1358 | default: |
1359 | break; | |
1360 | } | |
9ae8ffe7 | 1361 | |
45183e03 JH |
1362 | /* canon_rtx knows how to handle plus. No need to canonicalize. */ |
1363 | if (code == PLUS) | |
9ae8ffe7 JL |
1364 | return ((rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 0)) |
1365 | && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 1))) | |
1366 | || (rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 1)) | |
1367 | && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 0)))); | |
45183e03 JH |
1368 | /* For commutative operations, the RTX match if the operand match in any |
1369 | order. Also handle the simple binary and unary cases without a loop. */ | |
ec8e098d | 1370 | if (COMMUTATIVE_P (x)) |
45183e03 JH |
1371 | { |
1372 | rtx xop0 = canon_rtx (XEXP (x, 0)); | |
1373 | rtx yop0 = canon_rtx (XEXP (y, 0)); | |
1374 | rtx yop1 = canon_rtx (XEXP (y, 1)); | |
1375 | ||
1376 | return ((rtx_equal_for_memref_p (xop0, yop0) | |
1377 | && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), yop1)) | |
1378 | || (rtx_equal_for_memref_p (xop0, yop1) | |
1379 | && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), yop0))); | |
1380 | } | |
ec8e098d | 1381 | else if (NON_COMMUTATIVE_P (x)) |
45183e03 JH |
1382 | { |
1383 | return (rtx_equal_for_memref_p (canon_rtx (XEXP (x, 0)), | |
4682ae04 | 1384 | canon_rtx (XEXP (y, 0))) |
45183e03 JH |
1385 | && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), |
1386 | canon_rtx (XEXP (y, 1)))); | |
1387 | } | |
ec8e098d | 1388 | else if (UNARY_P (x)) |
45183e03 | 1389 | return rtx_equal_for_memref_p (canon_rtx (XEXP (x, 0)), |
4682ae04 | 1390 | canon_rtx (XEXP (y, 0))); |
9ae8ffe7 JL |
1391 | |
1392 | /* Compare the elements. If any pair of corresponding elements | |
de12be17 JC |
1393 | fail to match, return 0 for the whole things. |
1394 | ||
1395 | Limit cases to types which actually appear in addresses. */ | |
9ae8ffe7 JL |
1396 | |
1397 | fmt = GET_RTX_FORMAT (code); | |
1398 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
1399 | { | |
1400 | switch (fmt[i]) | |
1401 | { | |
9ae8ffe7 JL |
1402 | case 'i': |
1403 | if (XINT (x, i) != XINT (y, i)) | |
1404 | return 0; | |
1405 | break; | |
1406 | ||
9ae8ffe7 JL |
1407 | case 'E': |
1408 | /* Two vectors must have the same length. */ | |
1409 | if (XVECLEN (x, i) != XVECLEN (y, i)) | |
1410 | return 0; | |
1411 | ||
1412 | /* And the corresponding elements must match. */ | |
1413 | for (j = 0; j < XVECLEN (x, i); j++) | |
45183e03 JH |
1414 | if (rtx_equal_for_memref_p (canon_rtx (XVECEXP (x, i, j)), |
1415 | canon_rtx (XVECEXP (y, i, j))) == 0) | |
9ae8ffe7 JL |
1416 | return 0; |
1417 | break; | |
1418 | ||
1419 | case 'e': | |
45183e03 JH |
1420 | if (rtx_equal_for_memref_p (canon_rtx (XEXP (x, i)), |
1421 | canon_rtx (XEXP (y, i))) == 0) | |
9ae8ffe7 JL |
1422 | return 0; |
1423 | break; | |
1424 | ||
3237ac18 AH |
1425 | /* This can happen for asm operands. */ |
1426 | case 's': | |
1427 | if (strcmp (XSTR (x, i), XSTR (y, i))) | |
1428 | return 0; | |
1429 | break; | |
1430 | ||
aee21ba9 JL |
1431 | /* This can happen for an asm which clobbers memory. */ |
1432 | case '0': | |
1433 | break; | |
1434 | ||
9ae8ffe7 JL |
1435 | /* It is believed that rtx's at this level will never |
1436 | contain anything but integers and other rtx's, | |
1437 | except for within LABEL_REFs and SYMBOL_REFs. */ | |
1438 | default: | |
298e6adc | 1439 | gcc_unreachable (); |
9ae8ffe7 JL |
1440 | } |
1441 | } | |
1442 | return 1; | |
1443 | } | |
1444 | ||
94f24ddc | 1445 | rtx |
4682ae04 | 1446 | find_base_term (rtx x) |
9ae8ffe7 | 1447 | { |
eab5c70a BS |
1448 | cselib_val *val; |
1449 | struct elt_loc_list *l; | |
1450 | ||
b949ea8b JW |
1451 | #if defined (FIND_BASE_TERM) |
1452 | /* Try machine-dependent ways to find the base term. */ | |
1453 | x = FIND_BASE_TERM (x); | |
1454 | #endif | |
1455 | ||
9ae8ffe7 JL |
1456 | switch (GET_CODE (x)) |
1457 | { | |
1458 | case REG: | |
1459 | return REG_BASE_VALUE (x); | |
1460 | ||
d288e53d DE |
1461 | case TRUNCATE: |
1462 | if (GET_MODE_SIZE (GET_MODE (x)) < GET_MODE_SIZE (Pmode)) | |
ca7fd9cd | 1463 | return 0; |
d288e53d | 1464 | /* Fall through. */ |
9ae8ffe7 | 1465 | case HIGH: |
6d849a2a JL |
1466 | case PRE_INC: |
1467 | case PRE_DEC: | |
1468 | case POST_INC: | |
1469 | case POST_DEC: | |
d288e53d DE |
1470 | case PRE_MODIFY: |
1471 | case POST_MODIFY: | |
6d849a2a JL |
1472 | return find_base_term (XEXP (x, 0)); |
1473 | ||
1abade85 RK |
1474 | case ZERO_EXTEND: |
1475 | case SIGN_EXTEND: /* Used for Alpha/NT pointers */ | |
1476 | { | |
1477 | rtx temp = find_base_term (XEXP (x, 0)); | |
1478 | ||
5ae6cd0d | 1479 | if (temp != 0 && CONSTANT_P (temp)) |
1abade85 | 1480 | temp = convert_memory_address (Pmode, temp); |
1abade85 RK |
1481 | |
1482 | return temp; | |
1483 | } | |
1484 | ||
eab5c70a BS |
1485 | case VALUE: |
1486 | val = CSELIB_VAL_PTR (x); | |
40e02b4a JH |
1487 | if (!val) |
1488 | return 0; | |
eab5c70a BS |
1489 | for (l = val->locs; l; l = l->next) |
1490 | if ((x = find_base_term (l->loc)) != 0) | |
1491 | return x; | |
1492 | return 0; | |
1493 | ||
023f059b JJ |
1494 | case LO_SUM: |
1495 | /* The standard form is (lo_sum reg sym) so look only at the | |
1496 | second operand. */ | |
1497 | return find_base_term (XEXP (x, 1)); | |
1498 | ||
9ae8ffe7 JL |
1499 | case CONST: |
1500 | x = XEXP (x, 0); | |
1501 | if (GET_CODE (x) != PLUS && GET_CODE (x) != MINUS) | |
1502 | return 0; | |
938d968e | 1503 | /* Fall through. */ |
9ae8ffe7 JL |
1504 | case PLUS: |
1505 | case MINUS: | |
1506 | { | |
3c567fae JL |
1507 | rtx tmp1 = XEXP (x, 0); |
1508 | rtx tmp2 = XEXP (x, 1); | |
1509 | ||
f5143c46 | 1510 | /* This is a little bit tricky since we have to determine which of |
3c567fae JL |
1511 | the two operands represents the real base address. Otherwise this |
1512 | routine may return the index register instead of the base register. | |
1513 | ||
1514 | That may cause us to believe no aliasing was possible, when in | |
1515 | fact aliasing is possible. | |
1516 | ||
1517 | We use a few simple tests to guess the base register. Additional | |
1518 | tests can certainly be added. For example, if one of the operands | |
1519 | is a shift or multiply, then it must be the index register and the | |
1520 | other operand is the base register. */ | |
ca7fd9cd | 1521 | |
b949ea8b JW |
1522 | if (tmp1 == pic_offset_table_rtx && CONSTANT_P (tmp2)) |
1523 | return find_base_term (tmp2); | |
1524 | ||
3c567fae JL |
1525 | /* If either operand is known to be a pointer, then use it |
1526 | to determine the base term. */ | |
3502dc9c | 1527 | if (REG_P (tmp1) && REG_POINTER (tmp1)) |
7eba2d1f LM |
1528 | { |
1529 | rtx base = find_base_term (tmp1); | |
1530 | if (base) | |
1531 | return base; | |
1532 | } | |
3c567fae | 1533 | |
3502dc9c | 1534 | if (REG_P (tmp2) && REG_POINTER (tmp2)) |
7eba2d1f LM |
1535 | { |
1536 | rtx base = find_base_term (tmp2); | |
1537 | if (base) | |
1538 | return base; | |
1539 | } | |
3c567fae JL |
1540 | |
1541 | /* Neither operand was known to be a pointer. Go ahead and find the | |
1542 | base term for both operands. */ | |
1543 | tmp1 = find_base_term (tmp1); | |
1544 | tmp2 = find_base_term (tmp2); | |
1545 | ||
1546 | /* If either base term is named object or a special address | |
1547 | (like an argument or stack reference), then use it for the | |
1548 | base term. */ | |
d4b60170 | 1549 | if (tmp1 != 0 |
3c567fae JL |
1550 | && (GET_CODE (tmp1) == SYMBOL_REF |
1551 | || GET_CODE (tmp1) == LABEL_REF | |
1552 | || (GET_CODE (tmp1) == ADDRESS | |
1553 | && GET_MODE (tmp1) != VOIDmode))) | |
1554 | return tmp1; | |
1555 | ||
d4b60170 | 1556 | if (tmp2 != 0 |
3c567fae JL |
1557 | && (GET_CODE (tmp2) == SYMBOL_REF |
1558 | || GET_CODE (tmp2) == LABEL_REF | |
1559 | || (GET_CODE (tmp2) == ADDRESS | |
1560 | && GET_MODE (tmp2) != VOIDmode))) | |
1561 | return tmp2; | |
1562 | ||
1563 | /* We could not determine which of the two operands was the | |
1564 | base register and which was the index. So we can determine | |
1565 | nothing from the base alias check. */ | |
1566 | return 0; | |
9ae8ffe7 JL |
1567 | } |
1568 | ||
1569 | case AND: | |
481683e1 | 1570 | if (CONST_INT_P (XEXP (x, 1)) && INTVAL (XEXP (x, 1)) != 0) |
d288e53d | 1571 | return find_base_term (XEXP (x, 0)); |
9ae8ffe7 JL |
1572 | return 0; |
1573 | ||
1574 | case SYMBOL_REF: | |
1575 | case LABEL_REF: | |
1576 | return x; | |
1577 | ||
1578 | default: | |
1579 | return 0; | |
1580 | } | |
1581 | } | |
1582 | ||
1583 | /* Return 0 if the addresses X and Y are known to point to different | |
1584 | objects, 1 if they might be pointers to the same object. */ | |
1585 | ||
1586 | static int | |
4682ae04 AJ |
1587 | base_alias_check (rtx x, rtx y, enum machine_mode x_mode, |
1588 | enum machine_mode y_mode) | |
9ae8ffe7 JL |
1589 | { |
1590 | rtx x_base = find_base_term (x); | |
1591 | rtx y_base = find_base_term (y); | |
1592 | ||
1c72c7f6 JC |
1593 | /* If the address itself has no known base see if a known equivalent |
1594 | value has one. If either address still has no known base, nothing | |
1595 | is known about aliasing. */ | |
1596 | if (x_base == 0) | |
1597 | { | |
1598 | rtx x_c; | |
d4b60170 | 1599 | |
1c72c7f6 JC |
1600 | if (! flag_expensive_optimizations || (x_c = canon_rtx (x)) == x) |
1601 | return 1; | |
d4b60170 | 1602 | |
1c72c7f6 JC |
1603 | x_base = find_base_term (x_c); |
1604 | if (x_base == 0) | |
1605 | return 1; | |
1606 | } | |
9ae8ffe7 | 1607 | |
1c72c7f6 JC |
1608 | if (y_base == 0) |
1609 | { | |
1610 | rtx y_c; | |
1611 | if (! flag_expensive_optimizations || (y_c = canon_rtx (y)) == y) | |
1612 | return 1; | |
d4b60170 | 1613 | |
1c72c7f6 JC |
1614 | y_base = find_base_term (y_c); |
1615 | if (y_base == 0) | |
1616 | return 1; | |
1617 | } | |
1618 | ||
1619 | /* If the base addresses are equal nothing is known about aliasing. */ | |
1620 | if (rtx_equal_p (x_base, y_base)) | |
9ae8ffe7 JL |
1621 | return 1; |
1622 | ||
435da628 UB |
1623 | /* The base addresses are different expressions. If they are not accessed |
1624 | via AND, there is no conflict. We can bring knowledge of object | |
1625 | alignment into play here. For example, on alpha, "char a, b;" can | |
1626 | alias one another, though "char a; long b;" cannot. AND addesses may | |
1627 | implicitly alias surrounding objects; i.e. unaligned access in DImode | |
1628 | via AND address can alias all surrounding object types except those | |
1629 | with aligment 8 or higher. */ | |
1630 | if (GET_CODE (x) == AND && GET_CODE (y) == AND) | |
1631 | return 1; | |
1632 | if (GET_CODE (x) == AND | |
481683e1 | 1633 | && (!CONST_INT_P (XEXP (x, 1)) |
435da628 UB |
1634 | || (int) GET_MODE_UNIT_SIZE (y_mode) < -INTVAL (XEXP (x, 1)))) |
1635 | return 1; | |
1636 | if (GET_CODE (y) == AND | |
481683e1 | 1637 | && (!CONST_INT_P (XEXP (y, 1)) |
435da628 UB |
1638 | || (int) GET_MODE_UNIT_SIZE (x_mode) < -INTVAL (XEXP (y, 1)))) |
1639 | return 1; | |
1640 | ||
1641 | /* Differing symbols not accessed via AND never alias. */ | |
9ae8ffe7 | 1642 | if (GET_CODE (x_base) != ADDRESS && GET_CODE (y_base) != ADDRESS) |
435da628 | 1643 | return 0; |
9ae8ffe7 JL |
1644 | |
1645 | /* If one address is a stack reference there can be no alias: | |
1646 | stack references using different base registers do not alias, | |
1647 | a stack reference can not alias a parameter, and a stack reference | |
1648 | can not alias a global. */ | |
1649 | if ((GET_CODE (x_base) == ADDRESS && GET_MODE (x_base) == Pmode) | |
1650 | || (GET_CODE (y_base) == ADDRESS && GET_MODE (y_base) == Pmode)) | |
1651 | return 0; | |
1652 | ||
1653 | if (! flag_argument_noalias) | |
1654 | return 1; | |
1655 | ||
1656 | if (flag_argument_noalias > 1) | |
1657 | return 0; | |
1658 | ||
ec5c56db | 1659 | /* Weak noalias assertion (arguments are distinct, but may match globals). */ |
9ae8ffe7 JL |
1660 | return ! (GET_MODE (x_base) == VOIDmode && GET_MODE (y_base) == VOIDmode); |
1661 | } | |
1662 | ||
eab5c70a BS |
1663 | /* Convert the address X into something we can use. This is done by returning |
1664 | it unchanged unless it is a value; in the latter case we call cselib to get | |
1665 | a more useful rtx. */ | |
3bdf5ad1 | 1666 | |
a13d4ebf | 1667 | rtx |
4682ae04 | 1668 | get_addr (rtx x) |
eab5c70a BS |
1669 | { |
1670 | cselib_val *v; | |
1671 | struct elt_loc_list *l; | |
1672 | ||
1673 | if (GET_CODE (x) != VALUE) | |
1674 | return x; | |
1675 | v = CSELIB_VAL_PTR (x); | |
40e02b4a JH |
1676 | if (v) |
1677 | { | |
1678 | for (l = v->locs; l; l = l->next) | |
1679 | if (CONSTANT_P (l->loc)) | |
1680 | return l->loc; | |
1681 | for (l = v->locs; l; l = l->next) | |
3c0cb5de | 1682 | if (!REG_P (l->loc) && !MEM_P (l->loc)) |
40e02b4a JH |
1683 | return l->loc; |
1684 | if (v->locs) | |
1685 | return v->locs->loc; | |
1686 | } | |
eab5c70a BS |
1687 | return x; |
1688 | } | |
1689 | ||
39cec1ac MH |
1690 | /* Return the address of the (N_REFS + 1)th memory reference to ADDR |
1691 | where SIZE is the size in bytes of the memory reference. If ADDR | |
1692 | is not modified by the memory reference then ADDR is returned. */ | |
1693 | ||
04e2b4d3 | 1694 | static rtx |
4682ae04 | 1695 | addr_side_effect_eval (rtx addr, int size, int n_refs) |
39cec1ac MH |
1696 | { |
1697 | int offset = 0; | |
ca7fd9cd | 1698 | |
39cec1ac MH |
1699 | switch (GET_CODE (addr)) |
1700 | { | |
1701 | case PRE_INC: | |
1702 | offset = (n_refs + 1) * size; | |
1703 | break; | |
1704 | case PRE_DEC: | |
1705 | offset = -(n_refs + 1) * size; | |
1706 | break; | |
1707 | case POST_INC: | |
1708 | offset = n_refs * size; | |
1709 | break; | |
1710 | case POST_DEC: | |
1711 | offset = -n_refs * size; | |
1712 | break; | |
1713 | ||
1714 | default: | |
1715 | return addr; | |
1716 | } | |
ca7fd9cd | 1717 | |
39cec1ac | 1718 | if (offset) |
45183e03 | 1719 | addr = gen_rtx_PLUS (GET_MODE (addr), XEXP (addr, 0), |
c22cacf3 | 1720 | GEN_INT (offset)); |
39cec1ac MH |
1721 | else |
1722 | addr = XEXP (addr, 0); | |
45183e03 | 1723 | addr = canon_rtx (addr); |
39cec1ac MH |
1724 | |
1725 | return addr; | |
1726 | } | |
1727 | ||
9ae8ffe7 JL |
1728 | /* Return nonzero if X and Y (memory addresses) could reference the |
1729 | same location in memory. C is an offset accumulator. When | |
1730 | C is nonzero, we are testing aliases between X and Y + C. | |
1731 | XSIZE is the size in bytes of the X reference, | |
1732 | similarly YSIZE is the size in bytes for Y. | |
45183e03 | 1733 | Expect that canon_rtx has been already called for X and Y. |
9ae8ffe7 JL |
1734 | |
1735 | If XSIZE or YSIZE is zero, we do not know the amount of memory being | |
1736 | referenced (the reference was BLKmode), so make the most pessimistic | |
1737 | assumptions. | |
1738 | ||
c02f035f RH |
1739 | If XSIZE or YSIZE is negative, we may access memory outside the object |
1740 | being referenced as a side effect. This can happen when using AND to | |
1741 | align memory references, as is done on the Alpha. | |
1742 | ||
9ae8ffe7 | 1743 | Nice to notice that varying addresses cannot conflict with fp if no |
0211b6ab | 1744 | local variables had their addresses taken, but that's too hard now. */ |
9ae8ffe7 | 1745 | |
9ae8ffe7 | 1746 | static int |
4682ae04 | 1747 | memrefs_conflict_p (int xsize, rtx x, int ysize, rtx y, HOST_WIDE_INT c) |
9ae8ffe7 | 1748 | { |
eab5c70a BS |
1749 | if (GET_CODE (x) == VALUE) |
1750 | x = get_addr (x); | |
1751 | if (GET_CODE (y) == VALUE) | |
1752 | y = get_addr (y); | |
9ae8ffe7 JL |
1753 | if (GET_CODE (x) == HIGH) |
1754 | x = XEXP (x, 0); | |
1755 | else if (GET_CODE (x) == LO_SUM) | |
1756 | x = XEXP (x, 1); | |
1757 | else | |
45183e03 | 1758 | x = addr_side_effect_eval (x, xsize, 0); |
9ae8ffe7 JL |
1759 | if (GET_CODE (y) == HIGH) |
1760 | y = XEXP (y, 0); | |
1761 | else if (GET_CODE (y) == LO_SUM) | |
1762 | y = XEXP (y, 1); | |
1763 | else | |
45183e03 | 1764 | y = addr_side_effect_eval (y, ysize, 0); |
9ae8ffe7 JL |
1765 | |
1766 | if (rtx_equal_for_memref_p (x, y)) | |
1767 | { | |
c02f035f | 1768 | if (xsize <= 0 || ysize <= 0) |
9ae8ffe7 JL |
1769 | return 1; |
1770 | if (c >= 0 && xsize > c) | |
1771 | return 1; | |
1772 | if (c < 0 && ysize+c > 0) | |
1773 | return 1; | |
1774 | return 0; | |
1775 | } | |
1776 | ||
6e73e666 JC |
1777 | /* This code used to check for conflicts involving stack references and |
1778 | globals but the base address alias code now handles these cases. */ | |
9ae8ffe7 JL |
1779 | |
1780 | if (GET_CODE (x) == PLUS) | |
1781 | { | |
1782 | /* The fact that X is canonicalized means that this | |
1783 | PLUS rtx is canonicalized. */ | |
1784 | rtx x0 = XEXP (x, 0); | |
1785 | rtx x1 = XEXP (x, 1); | |
1786 | ||
1787 | if (GET_CODE (y) == PLUS) | |
1788 | { | |
1789 | /* The fact that Y is canonicalized means that this | |
1790 | PLUS rtx is canonicalized. */ | |
1791 | rtx y0 = XEXP (y, 0); | |
1792 | rtx y1 = XEXP (y, 1); | |
1793 | ||
1794 | if (rtx_equal_for_memref_p (x1, y1)) | |
1795 | return memrefs_conflict_p (xsize, x0, ysize, y0, c); | |
1796 | if (rtx_equal_for_memref_p (x0, y0)) | |
1797 | return memrefs_conflict_p (xsize, x1, ysize, y1, c); | |
481683e1 | 1798 | if (CONST_INT_P (x1)) |
63be02db | 1799 | { |
481683e1 | 1800 | if (CONST_INT_P (y1)) |
63be02db JM |
1801 | return memrefs_conflict_p (xsize, x0, ysize, y0, |
1802 | c - INTVAL (x1) + INTVAL (y1)); | |
1803 | else | |
1804 | return memrefs_conflict_p (xsize, x0, ysize, y, | |
1805 | c - INTVAL (x1)); | |
1806 | } | |
481683e1 | 1807 | else if (CONST_INT_P (y1)) |
9ae8ffe7 JL |
1808 | return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1)); |
1809 | ||
6e73e666 | 1810 | return 1; |
9ae8ffe7 | 1811 | } |
481683e1 | 1812 | else if (CONST_INT_P (x1)) |
9ae8ffe7 JL |
1813 | return memrefs_conflict_p (xsize, x0, ysize, y, c - INTVAL (x1)); |
1814 | } | |
1815 | else if (GET_CODE (y) == PLUS) | |
1816 | { | |
1817 | /* The fact that Y is canonicalized means that this | |
1818 | PLUS rtx is canonicalized. */ | |
1819 | rtx y0 = XEXP (y, 0); | |
1820 | rtx y1 = XEXP (y, 1); | |
1821 | ||
481683e1 | 1822 | if (CONST_INT_P (y1)) |
9ae8ffe7 JL |
1823 | return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1)); |
1824 | else | |
1825 | return 1; | |
1826 | } | |
1827 | ||
1828 | if (GET_CODE (x) == GET_CODE (y)) | |
1829 | switch (GET_CODE (x)) | |
1830 | { | |
1831 | case MULT: | |
1832 | { | |
1833 | /* Handle cases where we expect the second operands to be the | |
1834 | same, and check only whether the first operand would conflict | |
1835 | or not. */ | |
1836 | rtx x0, y0; | |
1837 | rtx x1 = canon_rtx (XEXP (x, 1)); | |
1838 | rtx y1 = canon_rtx (XEXP (y, 1)); | |
1839 | if (! rtx_equal_for_memref_p (x1, y1)) | |
1840 | return 1; | |
1841 | x0 = canon_rtx (XEXP (x, 0)); | |
1842 | y0 = canon_rtx (XEXP (y, 0)); | |
1843 | if (rtx_equal_for_memref_p (x0, y0)) | |
1844 | return (xsize == 0 || ysize == 0 | |
1845 | || (c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)); | |
1846 | ||
1847 | /* Can't properly adjust our sizes. */ | |
481683e1 | 1848 | if (!CONST_INT_P (x1)) |
9ae8ffe7 JL |
1849 | return 1; |
1850 | xsize /= INTVAL (x1); | |
1851 | ysize /= INTVAL (x1); | |
1852 | c /= INTVAL (x1); | |
1853 | return memrefs_conflict_p (xsize, x0, ysize, y0, c); | |
1854 | } | |
1d300e19 KG |
1855 | |
1856 | default: | |
1857 | break; | |
9ae8ffe7 JL |
1858 | } |
1859 | ||
1860 | /* Treat an access through an AND (e.g. a subword access on an Alpha) | |
ca7fd9cd | 1861 | as an access with indeterminate size. Assume that references |
56ee9281 RH |
1862 | besides AND are aligned, so if the size of the other reference is |
1863 | at least as large as the alignment, assume no other overlap. */ | |
481683e1 | 1864 | if (GET_CODE (x) == AND && CONST_INT_P (XEXP (x, 1))) |
56ee9281 | 1865 | { |
02e3377d | 1866 | if (GET_CODE (y) == AND || ysize < -INTVAL (XEXP (x, 1))) |
56ee9281 | 1867 | xsize = -1; |
45183e03 | 1868 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), ysize, y, c); |
56ee9281 | 1869 | } |
481683e1 | 1870 | if (GET_CODE (y) == AND && CONST_INT_P (XEXP (y, 1))) |
c02f035f | 1871 | { |
56ee9281 | 1872 | /* ??? If we are indexing far enough into the array/structure, we |
ca7fd9cd | 1873 | may yet be able to determine that we can not overlap. But we |
c02f035f | 1874 | also need to that we are far enough from the end not to overlap |
56ee9281 | 1875 | a following reference, so we do nothing with that for now. */ |
02e3377d | 1876 | if (GET_CODE (x) == AND || xsize < -INTVAL (XEXP (y, 1))) |
56ee9281 | 1877 | ysize = -1; |
45183e03 | 1878 | return memrefs_conflict_p (xsize, x, ysize, canon_rtx (XEXP (y, 0)), c); |
c02f035f | 1879 | } |
9ae8ffe7 JL |
1880 | |
1881 | if (CONSTANT_P (x)) | |
1882 | { | |
481683e1 | 1883 | if (CONST_INT_P (x) && CONST_INT_P (y)) |
9ae8ffe7 JL |
1884 | { |
1885 | c += (INTVAL (y) - INTVAL (x)); | |
c02f035f | 1886 | return (xsize <= 0 || ysize <= 0 |
9ae8ffe7 JL |
1887 | || (c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)); |
1888 | } | |
1889 | ||
1890 | if (GET_CODE (x) == CONST) | |
1891 | { | |
1892 | if (GET_CODE (y) == CONST) | |
1893 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), | |
1894 | ysize, canon_rtx (XEXP (y, 0)), c); | |
1895 | else | |
1896 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), | |
1897 | ysize, y, c); | |
1898 | } | |
1899 | if (GET_CODE (y) == CONST) | |
1900 | return memrefs_conflict_p (xsize, x, ysize, | |
1901 | canon_rtx (XEXP (y, 0)), c); | |
1902 | ||
1903 | if (CONSTANT_P (y)) | |
b949ea8b | 1904 | return (xsize <= 0 || ysize <= 0 |
c02f035f | 1905 | || (rtx_equal_for_memref_p (x, y) |
b949ea8b | 1906 | && ((c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)))); |
9ae8ffe7 JL |
1907 | |
1908 | return 1; | |
1909 | } | |
1910 | return 1; | |
1911 | } | |
1912 | ||
1913 | /* Functions to compute memory dependencies. | |
1914 | ||
1915 | Since we process the insns in execution order, we can build tables | |
1916 | to keep track of what registers are fixed (and not aliased), what registers | |
1917 | are varying in known ways, and what registers are varying in unknown | |
1918 | ways. | |
1919 | ||
1920 | If both memory references are volatile, then there must always be a | |
1921 | dependence between the two references, since their order can not be | |
1922 | changed. A volatile and non-volatile reference can be interchanged | |
ca7fd9cd | 1923 | though. |
9ae8ffe7 | 1924 | |
dc1618bc RK |
1925 | A MEM_IN_STRUCT reference at a non-AND varying address can never |
1926 | conflict with a non-MEM_IN_STRUCT reference at a fixed address. We | |
1927 | also must allow AND addresses, because they may generate accesses | |
1928 | outside the object being referenced. This is used to generate | |
1929 | aligned addresses from unaligned addresses, for instance, the alpha | |
1930 | storeqi_unaligned pattern. */ | |
9ae8ffe7 JL |
1931 | |
1932 | /* Read dependence: X is read after read in MEM takes place. There can | |
1933 | only be a dependence here if both reads are volatile. */ | |
1934 | ||
1935 | int | |
4f588890 | 1936 | read_dependence (const_rtx mem, const_rtx x) |
9ae8ffe7 JL |
1937 | { |
1938 | return MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem); | |
1939 | } | |
1940 | ||
c6df88cb MM |
1941 | /* Returns MEM1 if and only if MEM1 is a scalar at a fixed address and |
1942 | MEM2 is a reference to a structure at a varying address, or returns | |
1943 | MEM2 if vice versa. Otherwise, returns NULL_RTX. If a non-NULL | |
1944 | value is returned MEM1 and MEM2 can never alias. VARIES_P is used | |
1945 | to decide whether or not an address may vary; it should return | |
eab5c70a BS |
1946 | nonzero whenever variation is possible. |
1947 | MEM1_ADDR and MEM2_ADDR are the addresses of MEM1 and MEM2. */ | |
ca7fd9cd | 1948 | |
4f588890 KG |
1949 | static const_rtx |
1950 | fixed_scalar_and_varying_struct_p (const_rtx mem1, const_rtx mem2, rtx mem1_addr, | |
4682ae04 | 1951 | rtx mem2_addr, |
4f588890 | 1952 | bool (*varies_p) (const_rtx, bool)) |
ca7fd9cd | 1953 | { |
3e0abe15 GK |
1954 | if (! flag_strict_aliasing) |
1955 | return NULL_RTX; | |
1956 | ||
afa8f0fb AP |
1957 | if (MEM_ALIAS_SET (mem2) |
1958 | && MEM_SCALAR_P (mem1) && MEM_IN_STRUCT_P (mem2) | |
e38fe8e0 | 1959 | && !varies_p (mem1_addr, 1) && varies_p (mem2_addr, 1)) |
c6df88cb MM |
1960 | /* MEM1 is a scalar at a fixed address; MEM2 is a struct at a |
1961 | varying address. */ | |
1962 | return mem1; | |
1963 | ||
afa8f0fb AP |
1964 | if (MEM_ALIAS_SET (mem1) |
1965 | && MEM_IN_STRUCT_P (mem1) && MEM_SCALAR_P (mem2) | |
e38fe8e0 | 1966 | && varies_p (mem1_addr, 1) && !varies_p (mem2_addr, 1)) |
c6df88cb MM |
1967 | /* MEM2 is a scalar at a fixed address; MEM1 is a struct at a |
1968 | varying address. */ | |
1969 | return mem2; | |
1970 | ||
1971 | return NULL_RTX; | |
1972 | } | |
1973 | ||
1974 | /* Returns nonzero if something about the mode or address format MEM1 | |
1975 | indicates that it might well alias *anything*. */ | |
1976 | ||
2c72b78f | 1977 | static int |
4f588890 | 1978 | aliases_everything_p (const_rtx mem) |
c6df88cb | 1979 | { |
c6df88cb | 1980 | if (GET_CODE (XEXP (mem, 0)) == AND) |
35fd3193 | 1981 | /* If the address is an AND, it's very hard to know at what it is |
c6df88cb MM |
1982 | actually pointing. */ |
1983 | return 1; | |
ca7fd9cd | 1984 | |
c6df88cb MM |
1985 | return 0; |
1986 | } | |
1987 | ||
998d7deb RH |
1988 | /* Return true if we can determine that the fields referenced cannot |
1989 | overlap for any pair of objects. */ | |
1990 | ||
1991 | static bool | |
4f588890 | 1992 | nonoverlapping_component_refs_p (const_tree x, const_tree y) |
998d7deb | 1993 | { |
4f588890 | 1994 | const_tree fieldx, fieldy, typex, typey, orig_y; |
998d7deb | 1995 | |
4c7af939 AB |
1996 | if (!flag_strict_aliasing) |
1997 | return false; | |
1998 | ||
998d7deb RH |
1999 | do |
2000 | { | |
2001 | /* The comparison has to be done at a common type, since we don't | |
d6a7951f | 2002 | know how the inheritance hierarchy works. */ |
998d7deb RH |
2003 | orig_y = y; |
2004 | do | |
2005 | { | |
2006 | fieldx = TREE_OPERAND (x, 1); | |
c05a0766 | 2007 | typex = TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (fieldx)); |
998d7deb RH |
2008 | |
2009 | y = orig_y; | |
2010 | do | |
2011 | { | |
2012 | fieldy = TREE_OPERAND (y, 1); | |
c05a0766 | 2013 | typey = TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (fieldy)); |
998d7deb RH |
2014 | |
2015 | if (typex == typey) | |
2016 | goto found; | |
2017 | ||
2018 | y = TREE_OPERAND (y, 0); | |
2019 | } | |
2020 | while (y && TREE_CODE (y) == COMPONENT_REF); | |
2021 | ||
2022 | x = TREE_OPERAND (x, 0); | |
2023 | } | |
2024 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
998d7deb | 2025 | /* Never found a common type. */ |
c05a0766 | 2026 | return false; |
998d7deb RH |
2027 | |
2028 | found: | |
2029 | /* If we're left with accessing different fields of a structure, | |
2030 | then no overlap. */ | |
2031 | if (TREE_CODE (typex) == RECORD_TYPE | |
2032 | && fieldx != fieldy) | |
2033 | return true; | |
2034 | ||
2035 | /* The comparison on the current field failed. If we're accessing | |
2036 | a very nested structure, look at the next outer level. */ | |
2037 | x = TREE_OPERAND (x, 0); | |
2038 | y = TREE_OPERAND (y, 0); | |
2039 | } | |
2040 | while (x && y | |
2041 | && TREE_CODE (x) == COMPONENT_REF | |
2042 | && TREE_CODE (y) == COMPONENT_REF); | |
ca7fd9cd | 2043 | |
998d7deb RH |
2044 | return false; |
2045 | } | |
2046 | ||
2047 | /* Look at the bottom of the COMPONENT_REF list for a DECL, and return it. */ | |
2048 | ||
2049 | static tree | |
4682ae04 | 2050 | decl_for_component_ref (tree x) |
998d7deb RH |
2051 | { |
2052 | do | |
2053 | { | |
2054 | x = TREE_OPERAND (x, 0); | |
2055 | } | |
2056 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
2057 | ||
2058 | return x && DECL_P (x) ? x : NULL_TREE; | |
2059 | } | |
2060 | ||
2061 | /* Walk up the COMPONENT_REF list and adjust OFFSET to compensate for the | |
2062 | offset of the field reference. */ | |
2063 | ||
2064 | static rtx | |
4682ae04 | 2065 | adjust_offset_for_component_ref (tree x, rtx offset) |
998d7deb RH |
2066 | { |
2067 | HOST_WIDE_INT ioffset; | |
2068 | ||
2069 | if (! offset) | |
2070 | return NULL_RTX; | |
2071 | ||
2072 | ioffset = INTVAL (offset); | |
ca7fd9cd | 2073 | do |
998d7deb | 2074 | { |
44de5aeb | 2075 | tree offset = component_ref_field_offset (x); |
998d7deb RH |
2076 | tree field = TREE_OPERAND (x, 1); |
2077 | ||
44de5aeb | 2078 | if (! host_integerp (offset, 1)) |
998d7deb | 2079 | return NULL_RTX; |
44de5aeb | 2080 | ioffset += (tree_low_cst (offset, 1) |
998d7deb RH |
2081 | + (tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1) |
2082 | / BITS_PER_UNIT)); | |
2083 | ||
2084 | x = TREE_OPERAND (x, 0); | |
2085 | } | |
2086 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
2087 | ||
2088 | return GEN_INT (ioffset); | |
2089 | } | |
2090 | ||
95bd1dd7 | 2091 | /* Return nonzero if we can determine the exprs corresponding to memrefs |
a4311dfe RK |
2092 | X and Y and they do not overlap. */ |
2093 | ||
2e4e39f6 | 2094 | int |
4f588890 | 2095 | nonoverlapping_memrefs_p (const_rtx x, const_rtx y) |
a4311dfe | 2096 | { |
998d7deb | 2097 | tree exprx = MEM_EXPR (x), expry = MEM_EXPR (y); |
a4311dfe RK |
2098 | rtx rtlx, rtly; |
2099 | rtx basex, basey; | |
998d7deb | 2100 | rtx moffsetx, moffsety; |
a4311dfe RK |
2101 | HOST_WIDE_INT offsetx = 0, offsety = 0, sizex, sizey, tem; |
2102 | ||
998d7deb RH |
2103 | /* Unless both have exprs, we can't tell anything. */ |
2104 | if (exprx == 0 || expry == 0) | |
2105 | return 0; | |
c22cacf3 | 2106 | |
998d7deb RH |
2107 | /* If both are field references, we may be able to determine something. */ |
2108 | if (TREE_CODE (exprx) == COMPONENT_REF | |
2109 | && TREE_CODE (expry) == COMPONENT_REF | |
2110 | && nonoverlapping_component_refs_p (exprx, expry)) | |
2111 | return 1; | |
2112 | ||
c22cacf3 | 2113 | |
998d7deb RH |
2114 | /* If the field reference test failed, look at the DECLs involved. */ |
2115 | moffsetx = MEM_OFFSET (x); | |
2116 | if (TREE_CODE (exprx) == COMPONENT_REF) | |
2117 | { | |
ea900239 DB |
2118 | if (TREE_CODE (expry) == VAR_DECL |
2119 | && POINTER_TYPE_P (TREE_TYPE (expry))) | |
2120 | { | |
2121 | tree field = TREE_OPERAND (exprx, 1); | |
2122 | tree fieldcontext = DECL_FIELD_CONTEXT (field); | |
2123 | if (ipa_type_escape_field_does_not_clobber_p (fieldcontext, | |
2124 | TREE_TYPE (field))) | |
c22cacf3 | 2125 | return 1; |
ea900239 DB |
2126 | } |
2127 | { | |
2128 | tree t = decl_for_component_ref (exprx); | |
2129 | if (! t) | |
2130 | return 0; | |
2131 | moffsetx = adjust_offset_for_component_ref (exprx, moffsetx); | |
2132 | exprx = t; | |
2133 | } | |
998d7deb | 2134 | } |
1b096a0a | 2135 | else if (INDIRECT_REF_P (exprx)) |
c67a1cf6 RH |
2136 | { |
2137 | exprx = TREE_OPERAND (exprx, 0); | |
2138 | if (flag_argument_noalias < 2 | |
2139 | || TREE_CODE (exprx) != PARM_DECL) | |
2140 | return 0; | |
2141 | } | |
2142 | ||
998d7deb RH |
2143 | moffsety = MEM_OFFSET (y); |
2144 | if (TREE_CODE (expry) == COMPONENT_REF) | |
2145 | { | |
ea900239 DB |
2146 | if (TREE_CODE (exprx) == VAR_DECL |
2147 | && POINTER_TYPE_P (TREE_TYPE (exprx))) | |
2148 | { | |
2149 | tree field = TREE_OPERAND (expry, 1); | |
2150 | tree fieldcontext = DECL_FIELD_CONTEXT (field); | |
2151 | if (ipa_type_escape_field_does_not_clobber_p (fieldcontext, | |
2152 | TREE_TYPE (field))) | |
c22cacf3 | 2153 | return 1; |
ea900239 DB |
2154 | } |
2155 | { | |
2156 | tree t = decl_for_component_ref (expry); | |
2157 | if (! t) | |
2158 | return 0; | |
2159 | moffsety = adjust_offset_for_component_ref (expry, moffsety); | |
2160 | expry = t; | |
2161 | } | |
998d7deb | 2162 | } |
1b096a0a | 2163 | else if (INDIRECT_REF_P (expry)) |
c67a1cf6 RH |
2164 | { |
2165 | expry = TREE_OPERAND (expry, 0); | |
2166 | if (flag_argument_noalias < 2 | |
2167 | || TREE_CODE (expry) != PARM_DECL) | |
2168 | return 0; | |
2169 | } | |
998d7deb RH |
2170 | |
2171 | if (! DECL_P (exprx) || ! DECL_P (expry)) | |
a4311dfe RK |
2172 | return 0; |
2173 | ||
998d7deb RH |
2174 | rtlx = DECL_RTL (exprx); |
2175 | rtly = DECL_RTL (expry); | |
a4311dfe | 2176 | |
1edcd60b RK |
2177 | /* If either RTL is not a MEM, it must be a REG or CONCAT, meaning they |
2178 | can't overlap unless they are the same because we never reuse that part | |
2179 | of the stack frame used for locals for spilled pseudos. */ | |
3c0cb5de | 2180 | if ((!MEM_P (rtlx) || !MEM_P (rtly)) |
1edcd60b | 2181 | && ! rtx_equal_p (rtlx, rtly)) |
a4311dfe RK |
2182 | return 1; |
2183 | ||
2184 | /* Get the base and offsets of both decls. If either is a register, we | |
2185 | know both are and are the same, so use that as the base. The only | |
2186 | we can avoid overlap is if we can deduce that they are nonoverlapping | |
2187 | pieces of that decl, which is very rare. */ | |
3c0cb5de | 2188 | basex = MEM_P (rtlx) ? XEXP (rtlx, 0) : rtlx; |
481683e1 | 2189 | if (GET_CODE (basex) == PLUS && CONST_INT_P (XEXP (basex, 1))) |
a4311dfe RK |
2190 | offsetx = INTVAL (XEXP (basex, 1)), basex = XEXP (basex, 0); |
2191 | ||
3c0cb5de | 2192 | basey = MEM_P (rtly) ? XEXP (rtly, 0) : rtly; |
481683e1 | 2193 | if (GET_CODE (basey) == PLUS && CONST_INT_P (XEXP (basey, 1))) |
a4311dfe RK |
2194 | offsety = INTVAL (XEXP (basey, 1)), basey = XEXP (basey, 0); |
2195 | ||
d746694a | 2196 | /* If the bases are different, we know they do not overlap if both |
ca7fd9cd | 2197 | are constants or if one is a constant and the other a pointer into the |
d746694a RK |
2198 | stack frame. Otherwise a different base means we can't tell if they |
2199 | overlap or not. */ | |
2200 | if (! rtx_equal_p (basex, basey)) | |
ca7fd9cd KH |
2201 | return ((CONSTANT_P (basex) && CONSTANT_P (basey)) |
2202 | || (CONSTANT_P (basex) && REG_P (basey) | |
2203 | && REGNO_PTR_FRAME_P (REGNO (basey))) | |
2204 | || (CONSTANT_P (basey) && REG_P (basex) | |
2205 | && REGNO_PTR_FRAME_P (REGNO (basex)))); | |
a4311dfe | 2206 | |
3c0cb5de | 2207 | sizex = (!MEM_P (rtlx) ? (int) GET_MODE_SIZE (GET_MODE (rtlx)) |
a4311dfe RK |
2208 | : MEM_SIZE (rtlx) ? INTVAL (MEM_SIZE (rtlx)) |
2209 | : -1); | |
3c0cb5de | 2210 | sizey = (!MEM_P (rtly) ? (int) GET_MODE_SIZE (GET_MODE (rtly)) |
a4311dfe RK |
2211 | : MEM_SIZE (rtly) ? INTVAL (MEM_SIZE (rtly)) : |
2212 | -1); | |
2213 | ||
0af5bc3e RK |
2214 | /* If we have an offset for either memref, it can update the values computed |
2215 | above. */ | |
998d7deb RH |
2216 | if (moffsetx) |
2217 | offsetx += INTVAL (moffsetx), sizex -= INTVAL (moffsetx); | |
2218 | if (moffsety) | |
2219 | offsety += INTVAL (moffsety), sizey -= INTVAL (moffsety); | |
a4311dfe | 2220 | |
0af5bc3e | 2221 | /* If a memref has both a size and an offset, we can use the smaller size. |
efc981bb | 2222 | We can't do this if the offset isn't known because we must view this |
0af5bc3e | 2223 | memref as being anywhere inside the DECL's MEM. */ |
998d7deb | 2224 | if (MEM_SIZE (x) && moffsetx) |
a4311dfe | 2225 | sizex = INTVAL (MEM_SIZE (x)); |
998d7deb | 2226 | if (MEM_SIZE (y) && moffsety) |
a4311dfe RK |
2227 | sizey = INTVAL (MEM_SIZE (y)); |
2228 | ||
2229 | /* Put the values of the memref with the lower offset in X's values. */ | |
2230 | if (offsetx > offsety) | |
2231 | { | |
2232 | tem = offsetx, offsetx = offsety, offsety = tem; | |
2233 | tem = sizex, sizex = sizey, sizey = tem; | |
2234 | } | |
2235 | ||
2236 | /* If we don't know the size of the lower-offset value, we can't tell | |
2237 | if they conflict. Otherwise, we do the test. */ | |
a6f7c915 | 2238 | return sizex >= 0 && offsety >= offsetx + sizex; |
a4311dfe RK |
2239 | } |
2240 | ||
9ae8ffe7 JL |
2241 | /* True dependence: X is read after store in MEM takes place. */ |
2242 | ||
2243 | int | |
4f588890 KG |
2244 | true_dependence (const_rtx mem, enum machine_mode mem_mode, const_rtx x, |
2245 | bool (*varies) (const_rtx, bool)) | |
9ae8ffe7 | 2246 | { |
b3694847 | 2247 | rtx x_addr, mem_addr; |
49982682 | 2248 | rtx base; |
9ae8ffe7 JL |
2249 | |
2250 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) | |
2251 | return 1; | |
2252 | ||
c4484b8f | 2253 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
ac3768f6 | 2254 | This is used in epilogue deallocation functions, and in cselib. */ |
c4484b8f RH |
2255 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) |
2256 | return 1; | |
2257 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
2258 | return 1; | |
9cd9e512 RH |
2259 | if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER |
2260 | || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER) | |
2261 | return 1; | |
c4484b8f | 2262 | |
41472af8 MM |
2263 | if (DIFFERENT_ALIAS_SETS_P (x, mem)) |
2264 | return 0; | |
2265 | ||
389fdba0 RH |
2266 | /* Read-only memory is by definition never modified, and therefore can't |
2267 | conflict with anything. We don't expect to find read-only set on MEM, | |
41806d92 | 2268 | but stupid user tricks can produce them, so don't die. */ |
389fdba0 | 2269 | if (MEM_READONLY_P (x)) |
9ae8ffe7 JL |
2270 | return 0; |
2271 | ||
a4311dfe RK |
2272 | if (nonoverlapping_memrefs_p (mem, x)) |
2273 | return 0; | |
2274 | ||
56ee9281 RH |
2275 | if (mem_mode == VOIDmode) |
2276 | mem_mode = GET_MODE (mem); | |
2277 | ||
eab5c70a BS |
2278 | x_addr = get_addr (XEXP (x, 0)); |
2279 | mem_addr = get_addr (XEXP (mem, 0)); | |
2280 | ||
55efb413 JW |
2281 | base = find_base_term (x_addr); |
2282 | if (base && (GET_CODE (base) == LABEL_REF | |
2283 | || (GET_CODE (base) == SYMBOL_REF | |
2284 | && CONSTANT_POOL_ADDRESS_P (base)))) | |
2285 | return 0; | |
2286 | ||
eab5c70a | 2287 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), mem_mode)) |
1c72c7f6 JC |
2288 | return 0; |
2289 | ||
eab5c70a BS |
2290 | x_addr = canon_rtx (x_addr); |
2291 | mem_addr = canon_rtx (mem_addr); | |
6e73e666 | 2292 | |
0211b6ab JW |
2293 | if (! memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr, |
2294 | SIZE_FOR_MODE (x), x_addr, 0)) | |
2295 | return 0; | |
2296 | ||
c6df88cb | 2297 | if (aliases_everything_p (x)) |
0211b6ab JW |
2298 | return 1; |
2299 | ||
f5143c46 | 2300 | /* We cannot use aliases_everything_p to test MEM, since we must look |
c6df88cb MM |
2301 | at MEM_MODE, rather than GET_MODE (MEM). */ |
2302 | if (mem_mode == QImode || GET_CODE (mem_addr) == AND) | |
a13d4ebf AM |
2303 | return 1; |
2304 | ||
2305 | /* In true_dependence we also allow BLKmode to alias anything. Why | |
2306 | don't we do this in anti_dependence and output_dependence? */ | |
2307 | if (mem_mode == BLKmode || GET_MODE (x) == BLKmode) | |
2308 | return 1; | |
2309 | ||
55b34b5f RG |
2310 | if (fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, varies)) |
2311 | return 0; | |
2312 | ||
2313 | return rtx_refs_may_alias_p (x, mem, true); | |
a13d4ebf AM |
2314 | } |
2315 | ||
2316 | /* Canonical true dependence: X is read after store in MEM takes place. | |
ca7fd9cd KH |
2317 | Variant of true_dependence which assumes MEM has already been |
2318 | canonicalized (hence we no longer do that here). | |
2319 | The mem_addr argument has been added, since true_dependence computed | |
6216f94e JJ |
2320 | this value prior to canonicalizing. |
2321 | If x_addr is non-NULL, it is used in preference of XEXP (x, 0). */ | |
a13d4ebf AM |
2322 | |
2323 | int | |
4f588890 | 2324 | canon_true_dependence (const_rtx mem, enum machine_mode mem_mode, rtx mem_addr, |
6216f94e | 2325 | const_rtx x, rtx x_addr, bool (*varies) (const_rtx, bool)) |
a13d4ebf | 2326 | { |
a13d4ebf AM |
2327 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) |
2328 | return 1; | |
2329 | ||
0fe854a7 RH |
2330 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
2331 | This is used in epilogue deallocation functions. */ | |
2332 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) | |
2333 | return 1; | |
2334 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
2335 | return 1; | |
9cd9e512 RH |
2336 | if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER |
2337 | || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER) | |
2338 | return 1; | |
0fe854a7 | 2339 | |
a13d4ebf AM |
2340 | if (DIFFERENT_ALIAS_SETS_P (x, mem)) |
2341 | return 0; | |
2342 | ||
389fdba0 RH |
2343 | /* Read-only memory is by definition never modified, and therefore can't |
2344 | conflict with anything. We don't expect to find read-only set on MEM, | |
41806d92 | 2345 | but stupid user tricks can produce them, so don't die. */ |
389fdba0 | 2346 | if (MEM_READONLY_P (x)) |
a13d4ebf AM |
2347 | return 0; |
2348 | ||
a4311dfe RK |
2349 | if (nonoverlapping_memrefs_p (x, mem)) |
2350 | return 0; | |
2351 | ||
6216f94e JJ |
2352 | if (! x_addr) |
2353 | x_addr = get_addr (XEXP (x, 0)); | |
a13d4ebf AM |
2354 | |
2355 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), mem_mode)) | |
2356 | return 0; | |
2357 | ||
2358 | x_addr = canon_rtx (x_addr); | |
2359 | if (! memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr, | |
2360 | SIZE_FOR_MODE (x), x_addr, 0)) | |
2361 | return 0; | |
2362 | ||
2363 | if (aliases_everything_p (x)) | |
2364 | return 1; | |
2365 | ||
f5143c46 | 2366 | /* We cannot use aliases_everything_p to test MEM, since we must look |
a13d4ebf AM |
2367 | at MEM_MODE, rather than GET_MODE (MEM). */ |
2368 | if (mem_mode == QImode || GET_CODE (mem_addr) == AND) | |
c6df88cb | 2369 | return 1; |
0211b6ab | 2370 | |
c6df88cb MM |
2371 | /* In true_dependence we also allow BLKmode to alias anything. Why |
2372 | don't we do this in anti_dependence and output_dependence? */ | |
2373 | if (mem_mode == BLKmode || GET_MODE (x) == BLKmode) | |
2374 | return 1; | |
0211b6ab | 2375 | |
55b34b5f RG |
2376 | if (fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, varies)) |
2377 | return 0; | |
2378 | ||
2379 | return rtx_refs_may_alias_p (x, mem, true); | |
9ae8ffe7 JL |
2380 | } |
2381 | ||
da7d8304 | 2382 | /* Returns nonzero if a write to X might alias a previous read from |
389fdba0 | 2383 | (or, if WRITEP is nonzero, a write to) MEM. */ |
9ae8ffe7 | 2384 | |
2c72b78f | 2385 | static int |
4f588890 | 2386 | write_dependence_p (const_rtx mem, const_rtx x, int writep) |
9ae8ffe7 | 2387 | { |
6e73e666 | 2388 | rtx x_addr, mem_addr; |
4f588890 | 2389 | const_rtx fixed_scalar; |
49982682 | 2390 | rtx base; |
6e73e666 | 2391 | |
9ae8ffe7 JL |
2392 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) |
2393 | return 1; | |
2394 | ||
c4484b8f RH |
2395 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
2396 | This is used in epilogue deallocation functions. */ | |
2397 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) | |
2398 | return 1; | |
2399 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
2400 | return 1; | |
9cd9e512 RH |
2401 | if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER |
2402 | || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER) | |
2403 | return 1; | |
c4484b8f | 2404 | |
389fdba0 RH |
2405 | /* A read from read-only memory can't conflict with read-write memory. */ |
2406 | if (!writep && MEM_READONLY_P (mem)) | |
2407 | return 0; | |
55efb413 | 2408 | |
a4311dfe RK |
2409 | if (nonoverlapping_memrefs_p (x, mem)) |
2410 | return 0; | |
2411 | ||
55efb413 JW |
2412 | x_addr = get_addr (XEXP (x, 0)); |
2413 | mem_addr = get_addr (XEXP (mem, 0)); | |
2414 | ||
49982682 JW |
2415 | if (! writep) |
2416 | { | |
55efb413 | 2417 | base = find_base_term (mem_addr); |
49982682 JW |
2418 | if (base && (GET_CODE (base) == LABEL_REF |
2419 | || (GET_CODE (base) == SYMBOL_REF | |
2420 | && CONSTANT_POOL_ADDRESS_P (base)))) | |
2421 | return 0; | |
2422 | } | |
2423 | ||
eab5c70a BS |
2424 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), |
2425 | GET_MODE (mem))) | |
41472af8 MM |
2426 | return 0; |
2427 | ||
eab5c70a BS |
2428 | x_addr = canon_rtx (x_addr); |
2429 | mem_addr = canon_rtx (mem_addr); | |
6e73e666 | 2430 | |
c6df88cb MM |
2431 | if (!memrefs_conflict_p (SIZE_FOR_MODE (mem), mem_addr, |
2432 | SIZE_FOR_MODE (x), x_addr, 0)) | |
2433 | return 0; | |
2434 | ||
ca7fd9cd | 2435 | fixed_scalar |
eab5c70a BS |
2436 | = fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, |
2437 | rtx_addr_varies_p); | |
2438 | ||
55b34b5f RG |
2439 | if ((fixed_scalar == mem && !aliases_everything_p (x)) |
2440 | || (fixed_scalar == x && !aliases_everything_p (mem))) | |
2441 | return 0; | |
2442 | ||
2443 | return rtx_refs_may_alias_p (x, mem, false); | |
c6df88cb MM |
2444 | } |
2445 | ||
2446 | /* Anti dependence: X is written after read in MEM takes place. */ | |
2447 | ||
2448 | int | |
4f588890 | 2449 | anti_dependence (const_rtx mem, const_rtx x) |
c6df88cb | 2450 | { |
389fdba0 | 2451 | return write_dependence_p (mem, x, /*writep=*/0); |
9ae8ffe7 JL |
2452 | } |
2453 | ||
2454 | /* Output dependence: X is written after store in MEM takes place. */ | |
2455 | ||
2456 | int | |
4f588890 | 2457 | output_dependence (const_rtx mem, const_rtx x) |
9ae8ffe7 | 2458 | { |
389fdba0 | 2459 | return write_dependence_p (mem, x, /*writep=*/1); |
9ae8ffe7 | 2460 | } |
c14b9960 | 2461 | \f |
6e73e666 | 2462 | |
6e73e666 | 2463 | void |
b5deb7b6 | 2464 | init_alias_target (void) |
6e73e666 | 2465 | { |
b3694847 | 2466 | int i; |
6e73e666 | 2467 | |
b5deb7b6 SL |
2468 | memset (static_reg_base_value, 0, sizeof static_reg_base_value); |
2469 | ||
6e73e666 JC |
2470 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) |
2471 | /* Check whether this register can hold an incoming pointer | |
2472 | argument. FUNCTION_ARG_REGNO_P tests outgoing register | |
ec5c56db | 2473 | numbers, so translate if necessary due to register windows. */ |
6e73e666 JC |
2474 | if (FUNCTION_ARG_REGNO_P (OUTGOING_REGNO (i)) |
2475 | && HARD_REGNO_MODE_OK (i, Pmode)) | |
bf1660a6 JL |
2476 | static_reg_base_value[i] |
2477 | = gen_rtx_ADDRESS (VOIDmode, gen_rtx_REG (Pmode, i)); | |
2478 | ||
bf1660a6 JL |
2479 | static_reg_base_value[STACK_POINTER_REGNUM] |
2480 | = gen_rtx_ADDRESS (Pmode, stack_pointer_rtx); | |
2481 | static_reg_base_value[ARG_POINTER_REGNUM] | |
2482 | = gen_rtx_ADDRESS (Pmode, arg_pointer_rtx); | |
2483 | static_reg_base_value[FRAME_POINTER_REGNUM] | |
2484 | = gen_rtx_ADDRESS (Pmode, frame_pointer_rtx); | |
2485 | #if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM | |
2486 | static_reg_base_value[HARD_FRAME_POINTER_REGNUM] | |
2487 | = gen_rtx_ADDRESS (Pmode, hard_frame_pointer_rtx); | |
2488 | #endif | |
2489 | } | |
2490 | ||
7b52eede JH |
2491 | /* Set MEMORY_MODIFIED when X modifies DATA (that is assumed |
2492 | to be memory reference. */ | |
2493 | static bool memory_modified; | |
2494 | static void | |
aa317c97 | 2495 | memory_modified_1 (rtx x, const_rtx pat ATTRIBUTE_UNUSED, void *data) |
7b52eede | 2496 | { |
3c0cb5de | 2497 | if (MEM_P (x)) |
7b52eede | 2498 | { |
9678086d | 2499 | if (anti_dependence (x, (const_rtx)data) || output_dependence (x, (const_rtx)data)) |
7b52eede JH |
2500 | memory_modified = true; |
2501 | } | |
2502 | } | |
2503 | ||
2504 | ||
2505 | /* Return true when INSN possibly modify memory contents of MEM | |
454ff5cb | 2506 | (i.e. address can be modified). */ |
7b52eede | 2507 | bool |
9678086d | 2508 | memory_modified_in_insn_p (const_rtx mem, const_rtx insn) |
7b52eede JH |
2509 | { |
2510 | if (!INSN_P (insn)) | |
2511 | return false; | |
2512 | memory_modified = false; | |
aa317c97 | 2513 | note_stores (PATTERN (insn), memory_modified_1, CONST_CAST_RTX(mem)); |
7b52eede JH |
2514 | return memory_modified; |
2515 | } | |
2516 | ||
c13e8210 MM |
2517 | /* Initialize the aliasing machinery. Initialize the REG_KNOWN_VALUE |
2518 | array. */ | |
2519 | ||
9ae8ffe7 | 2520 | void |
4682ae04 | 2521 | init_alias_analysis (void) |
9ae8ffe7 | 2522 | { |
c582d54a | 2523 | unsigned int maxreg = max_reg_num (); |
ea64ef27 | 2524 | int changed, pass; |
b3694847 SS |
2525 | int i; |
2526 | unsigned int ui; | |
2527 | rtx insn; | |
9ae8ffe7 | 2528 | |
0d446150 JH |
2529 | timevar_push (TV_ALIAS_ANALYSIS); |
2530 | ||
bb1acb3e | 2531 | reg_known_value_size = maxreg - FIRST_PSEUDO_REGISTER; |
f883e0a7 KG |
2532 | reg_known_value = GGC_CNEWVEC (rtx, reg_known_value_size); |
2533 | reg_known_equiv_p = XCNEWVEC (bool, reg_known_value_size); | |
9ae8ffe7 | 2534 | |
08c79682 | 2535 | /* If we have memory allocated from the previous run, use it. */ |
c582d54a | 2536 | if (old_reg_base_value) |
08c79682 KH |
2537 | reg_base_value = old_reg_base_value; |
2538 | ||
2539 | if (reg_base_value) | |
2540 | VEC_truncate (rtx, reg_base_value, 0); | |
2541 | ||
a590ac65 | 2542 | VEC_safe_grow_cleared (rtx, gc, reg_base_value, maxreg); |
ac606739 | 2543 | |
5ed6ace5 MD |
2544 | new_reg_base_value = XNEWVEC (rtx, maxreg); |
2545 | reg_seen = XNEWVEC (char, maxreg); | |
ec907dd8 JL |
2546 | |
2547 | /* The basic idea is that each pass through this loop will use the | |
2548 | "constant" information from the previous pass to propagate alias | |
2549 | information through another level of assignments. | |
2550 | ||
2551 | This could get expensive if the assignment chains are long. Maybe | |
2552 | we should throttle the number of iterations, possibly based on | |
6e73e666 | 2553 | the optimization level or flag_expensive_optimizations. |
ec907dd8 JL |
2554 | |
2555 | We could propagate more information in the first pass by making use | |
6fb5fa3c | 2556 | of DF_REG_DEF_COUNT to determine immediately that the alias information |
ea64ef27 JL |
2557 | for a pseudo is "constant". |
2558 | ||
2559 | A program with an uninitialized variable can cause an infinite loop | |
2560 | here. Instead of doing a full dataflow analysis to detect such problems | |
2561 | we just cap the number of iterations for the loop. | |
2562 | ||
2563 | The state of the arrays for the set chain in question does not matter | |
2564 | since the program has undefined behavior. */ | |
6e73e666 | 2565 | |
ea64ef27 | 2566 | pass = 0; |
6e73e666 | 2567 | do |
ec907dd8 JL |
2568 | { |
2569 | /* Assume nothing will change this iteration of the loop. */ | |
2570 | changed = 0; | |
2571 | ||
ec907dd8 JL |
2572 | /* We want to assign the same IDs each iteration of this loop, so |
2573 | start counting from zero each iteration of the loop. */ | |
2574 | unique_id = 0; | |
2575 | ||
f5143c46 | 2576 | /* We're at the start of the function each iteration through the |
ec907dd8 | 2577 | loop, so we're copying arguments. */ |
83bbd9b6 | 2578 | copying_arguments = true; |
9ae8ffe7 | 2579 | |
6e73e666 | 2580 | /* Wipe the potential alias information clean for this pass. */ |
c582d54a | 2581 | memset (new_reg_base_value, 0, maxreg * sizeof (rtx)); |
8072f69c | 2582 | |
6e73e666 | 2583 | /* Wipe the reg_seen array clean. */ |
c582d54a | 2584 | memset (reg_seen, 0, maxreg); |
9ae8ffe7 | 2585 | |
6e73e666 JC |
2586 | /* Mark all hard registers which may contain an address. |
2587 | The stack, frame and argument pointers may contain an address. | |
2588 | An argument register which can hold a Pmode value may contain | |
2589 | an address even if it is not in BASE_REGS. | |
8072f69c | 2590 | |
6e73e666 JC |
2591 | The address expression is VOIDmode for an argument and |
2592 | Pmode for other registers. */ | |
2593 | ||
7f243674 JL |
2594 | memcpy (new_reg_base_value, static_reg_base_value, |
2595 | FIRST_PSEUDO_REGISTER * sizeof (rtx)); | |
6e73e666 | 2596 | |
ec907dd8 JL |
2597 | /* Walk the insns adding values to the new_reg_base_value array. */ |
2598 | for (insn = get_insns (); insn; insn = NEXT_INSN (insn)) | |
9ae8ffe7 | 2599 | { |
2c3c49de | 2600 | if (INSN_P (insn)) |
ec907dd8 | 2601 | { |
6e73e666 | 2602 | rtx note, set; |
efc9bd41 RK |
2603 | |
2604 | #if defined (HAVE_prologue) || defined (HAVE_epilogue) | |
f5143c46 | 2605 | /* The prologue/epilogue insns are not threaded onto the |
657959ca JL |
2606 | insn chain until after reload has completed. Thus, |
2607 | there is no sense wasting time checking if INSN is in | |
2608 | the prologue/epilogue until after reload has completed. */ | |
2609 | if (reload_completed | |
2610 | && prologue_epilogue_contains (insn)) | |
efc9bd41 RK |
2611 | continue; |
2612 | #endif | |
2613 | ||
ec907dd8 | 2614 | /* If this insn has a noalias note, process it, Otherwise, |
c22cacf3 MS |
2615 | scan for sets. A simple set will have no side effects |
2616 | which could change the base value of any other register. */ | |
6e73e666 | 2617 | |
ec907dd8 | 2618 | if (GET_CODE (PATTERN (insn)) == SET |
efc9bd41 RK |
2619 | && REG_NOTES (insn) != 0 |
2620 | && find_reg_note (insn, REG_NOALIAS, NULL_RTX)) | |
84832317 | 2621 | record_set (SET_DEST (PATTERN (insn)), NULL_RTX, NULL); |
ec907dd8 | 2622 | else |
84832317 | 2623 | note_stores (PATTERN (insn), record_set, NULL); |
6e73e666 JC |
2624 | |
2625 | set = single_set (insn); | |
2626 | ||
2627 | if (set != 0 | |
f8cfc6aa | 2628 | && REG_P (SET_DEST (set)) |
fb6754f0 | 2629 | && REGNO (SET_DEST (set)) >= FIRST_PSEUDO_REGISTER) |
6e73e666 | 2630 | { |
fb6754f0 | 2631 | unsigned int regno = REGNO (SET_DEST (set)); |
713f41f9 | 2632 | rtx src = SET_SRC (set); |
bb1acb3e | 2633 | rtx t; |
713f41f9 | 2634 | |
a31830a7 SB |
2635 | note = find_reg_equal_equiv_note (insn); |
2636 | if (note && REG_NOTE_KIND (note) == REG_EQUAL | |
6fb5fa3c | 2637 | && DF_REG_DEF_COUNT (regno) != 1) |
a31830a7 SB |
2638 | note = NULL_RTX; |
2639 | ||
2640 | if (note != NULL_RTX | |
713f41f9 | 2641 | && GET_CODE (XEXP (note, 0)) != EXPR_LIST |
bb2cf916 | 2642 | && ! rtx_varies_p (XEXP (note, 0), 1) |
bb1acb3e RH |
2643 | && ! reg_overlap_mentioned_p (SET_DEST (set), |
2644 | XEXP (note, 0))) | |
713f41f9 | 2645 | { |
bb1acb3e RH |
2646 | set_reg_known_value (regno, XEXP (note, 0)); |
2647 | set_reg_known_equiv_p (regno, | |
2648 | REG_NOTE_KIND (note) == REG_EQUIV); | |
713f41f9 | 2649 | } |
6fb5fa3c | 2650 | else if (DF_REG_DEF_COUNT (regno) == 1 |
713f41f9 | 2651 | && GET_CODE (src) == PLUS |
f8cfc6aa | 2652 | && REG_P (XEXP (src, 0)) |
bb1acb3e | 2653 | && (t = get_reg_known_value (REGNO (XEXP (src, 0)))) |
481683e1 | 2654 | && CONST_INT_P (XEXP (src, 1))) |
713f41f9 | 2655 | { |
bb1acb3e RH |
2656 | t = plus_constant (t, INTVAL (XEXP (src, 1))); |
2657 | set_reg_known_value (regno, t); | |
2658 | set_reg_known_equiv_p (regno, 0); | |
713f41f9 | 2659 | } |
6fb5fa3c | 2660 | else if (DF_REG_DEF_COUNT (regno) == 1 |
713f41f9 BS |
2661 | && ! rtx_varies_p (src, 1)) |
2662 | { | |
bb1acb3e RH |
2663 | set_reg_known_value (regno, src); |
2664 | set_reg_known_equiv_p (regno, 0); | |
713f41f9 | 2665 | } |
6e73e666 | 2666 | } |
ec907dd8 | 2667 | } |
4b4bf941 | 2668 | else if (NOTE_P (insn) |
a38e7aa5 | 2669 | && NOTE_KIND (insn) == NOTE_INSN_FUNCTION_BEG) |
83bbd9b6 | 2670 | copying_arguments = false; |
6e73e666 | 2671 | } |
ec907dd8 | 2672 | |
6e73e666 | 2673 | /* Now propagate values from new_reg_base_value to reg_base_value. */ |
62e5bf5d | 2674 | gcc_assert (maxreg == (unsigned int) max_reg_num ()); |
c22cacf3 | 2675 | |
c582d54a | 2676 | for (ui = 0; ui < maxreg; ui++) |
6e73e666 | 2677 | { |
e51712db | 2678 | if (new_reg_base_value[ui] |
08c79682 | 2679 | && new_reg_base_value[ui] != VEC_index (rtx, reg_base_value, ui) |
c582d54a | 2680 | && ! rtx_equal_p (new_reg_base_value[ui], |
08c79682 | 2681 | VEC_index (rtx, reg_base_value, ui))) |
ec907dd8 | 2682 | { |
08c79682 | 2683 | VEC_replace (rtx, reg_base_value, ui, new_reg_base_value[ui]); |
6e73e666 | 2684 | changed = 1; |
ec907dd8 | 2685 | } |
9ae8ffe7 | 2686 | } |
9ae8ffe7 | 2687 | } |
6e73e666 | 2688 | while (changed && ++pass < MAX_ALIAS_LOOP_PASSES); |
9ae8ffe7 JL |
2689 | |
2690 | /* Fill in the remaining entries. */ | |
bb1acb3e | 2691 | for (i = 0; i < (int)reg_known_value_size; i++) |
9ae8ffe7 | 2692 | if (reg_known_value[i] == 0) |
bb1acb3e | 2693 | reg_known_value[i] = regno_reg_rtx[i + FIRST_PSEUDO_REGISTER]; |
9ae8ffe7 | 2694 | |
e05e2395 MM |
2695 | /* Clean up. */ |
2696 | free (new_reg_base_value); | |
ec907dd8 | 2697 | new_reg_base_value = 0; |
e05e2395 | 2698 | free (reg_seen); |
9ae8ffe7 | 2699 | reg_seen = 0; |
0d446150 | 2700 | timevar_pop (TV_ALIAS_ANALYSIS); |
9ae8ffe7 JL |
2701 | } |
2702 | ||
2703 | void | |
4682ae04 | 2704 | end_alias_analysis (void) |
9ae8ffe7 | 2705 | { |
c582d54a | 2706 | old_reg_base_value = reg_base_value; |
bb1acb3e | 2707 | ggc_free (reg_known_value); |
9ae8ffe7 | 2708 | reg_known_value = 0; |
ac606739 | 2709 | reg_known_value_size = 0; |
bb1acb3e | 2710 | free (reg_known_equiv_p); |
e05e2395 | 2711 | reg_known_equiv_p = 0; |
9ae8ffe7 | 2712 | } |
e2500fed GK |
2713 | |
2714 | #include "gt-alias.h" |