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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, |
757e8ba2 | 3 | 2007, 2008, 2009, 2010, 2011, 2012 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" |
718f9c0f | 36 | #include "diagnostic-core.h" |
eab5c70a | 37 | #include "cselib.h" |
3932261a | 38 | #include "splay-tree.h" |
ac606739 | 39 | #include "ggc.h" |
d23c55c2 | 40 | #include "langhooks.h" |
0d446150 | 41 | #include "timevar.h" |
7ee2468b | 42 | #include "dumpfile.h" |
ab780373 | 43 | #include "target.h" |
b255a036 | 44 | #include "cgraph.h" |
6fb5fa3c | 45 | #include "df.h" |
55b34b5f RG |
46 | #include "tree-ssa-alias.h" |
47 | #include "pointer-set.h" | |
48 | #include "tree-flow.h" | |
ea900239 DB |
49 | |
50 | /* The aliasing API provided here solves related but different problems: | |
51 | ||
c22cacf3 | 52 | Say there exists (in c) |
ea900239 DB |
53 | |
54 | struct X { | |
55 | struct Y y1; | |
56 | struct Z z2; | |
57 | } x1, *px1, *px2; | |
58 | ||
59 | struct Y y2, *py; | |
60 | struct Z z2, *pz; | |
61 | ||
62 | ||
63 | py = &px1.y1; | |
64 | px2 = &x1; | |
65 | ||
66 | Consider the four questions: | |
67 | ||
68 | Can a store to x1 interfere with px2->y1? | |
69 | Can a store to x1 interfere with px2->z2? | |
70 | (*px2).z2 | |
71 | Can a store to x1 change the value pointed to by with py? | |
72 | Can a store to x1 change the value pointed to by with pz? | |
73 | ||
74 | The answer to these questions can be yes, yes, yes, and maybe. | |
75 | ||
76 | The first two questions can be answered with a simple examination | |
77 | of the type system. If structure X contains a field of type Y then | |
073a8998 | 78 | a store through a pointer to an X can overwrite any field that is |
ea900239 DB |
79 | contained (recursively) in an X (unless we know that px1 != px2). |
80 | ||
81 | The last two of the questions can be solved in the same way as the | |
82 | first two questions but this is too conservative. The observation | |
83 | is that in some cases analysis we can know if which (if any) fields | |
84 | are addressed and if those addresses are used in bad ways. This | |
85 | analysis may be language specific. In C, arbitrary operations may | |
86 | be applied to pointers. However, there is some indication that | |
87 | this may be too conservative for some C++ types. | |
88 | ||
89 | The pass ipa-type-escape does this analysis for the types whose | |
c22cacf3 | 90 | instances do not escape across the compilation boundary. |
ea900239 DB |
91 | |
92 | Historically in GCC, these two problems were combined and a single | |
93 | data structure was used to represent the solution to these | |
94 | problems. We now have two similar but different data structures, | |
95 | The data structure to solve the last two question is similar to the | |
96 | first, but does not contain have the fields in it whose address are | |
97 | never taken. For types that do escape the compilation unit, the | |
98 | data structures will have identical information. | |
99 | */ | |
3932261a MM |
100 | |
101 | /* The alias sets assigned to MEMs assist the back-end in determining | |
102 | which MEMs can alias which other MEMs. In general, two MEMs in | |
ac3d9668 RK |
103 | different alias sets cannot alias each other, with one important |
104 | exception. Consider something like: | |
3932261a | 105 | |
01d28c3f | 106 | struct S { int i; double d; }; |
3932261a MM |
107 | |
108 | a store to an `S' can alias something of either type `int' or type | |
109 | `double'. (However, a store to an `int' cannot alias a `double' | |
110 | and vice versa.) We indicate this via a tree structure that looks | |
111 | like: | |
c22cacf3 MS |
112 | struct S |
113 | / \ | |
3932261a | 114 | / \ |
c22cacf3 MS |
115 | |/_ _\| |
116 | int double | |
3932261a | 117 | |
ac3d9668 RK |
118 | (The arrows are directed and point downwards.) |
119 | In this situation we say the alias set for `struct S' is the | |
120 | `superset' and that those for `int' and `double' are `subsets'. | |
121 | ||
3bdf5ad1 RK |
122 | To see whether two alias sets can point to the same memory, we must |
123 | see if either alias set is a subset of the other. We need not trace | |
95bd1dd7 | 124 | past immediate descendants, however, since we propagate all |
3bdf5ad1 | 125 | grandchildren up one level. |
3932261a MM |
126 | |
127 | Alias set zero is implicitly a superset of all other alias sets. | |
128 | However, this is no actual entry for alias set zero. It is an | |
129 | error to attempt to explicitly construct a subset of zero. */ | |
130 | ||
7e5487a2 | 131 | struct GTY(()) alias_set_entry_d { |
3932261a | 132 | /* The alias set number, as stored in MEM_ALIAS_SET. */ |
4862826d | 133 | alias_set_type alias_set; |
3932261a | 134 | |
4c067742 RG |
135 | /* Nonzero if would have a child of zero: this effectively makes this |
136 | alias set the same as alias set zero. */ | |
137 | int has_zero_child; | |
138 | ||
3932261a | 139 | /* The children of the alias set. These are not just the immediate |
95bd1dd7 | 140 | children, but, in fact, all descendants. So, if we have: |
3932261a | 141 | |
ca7fd9cd | 142 | struct T { struct S s; float f; } |
3932261a MM |
143 | |
144 | continuing our example above, the children here will be all of | |
145 | `int', `double', `float', and `struct S'. */ | |
b604074c | 146 | splay_tree GTY((param1_is (int), param2_is (int))) children; |
b604074c | 147 | }; |
7e5487a2 | 148 | typedef struct alias_set_entry_d *alias_set_entry; |
9ae8ffe7 | 149 | |
ed7a4b4b | 150 | static int rtx_equal_for_memref_p (const_rtx, const_rtx); |
4682ae04 | 151 | static int memrefs_conflict_p (int, rtx, int, rtx, HOST_WIDE_INT); |
7bc980e1 | 152 | static void record_set (rtx, const_rtx, void *); |
4682ae04 AJ |
153 | static int base_alias_check (rtx, rtx, enum machine_mode, |
154 | enum machine_mode); | |
155 | static rtx find_base_value (rtx); | |
4f588890 | 156 | static int mems_in_disjoint_alias_sets_p (const_rtx, const_rtx); |
4682ae04 | 157 | static int insert_subset_children (splay_tree_node, void*); |
4862826d | 158 | static alias_set_entry get_alias_set_entry (alias_set_type); |
175a7536 | 159 | static bool nonoverlapping_component_refs_p (const_rtx, const_rtx); |
4682ae04 | 160 | static tree decl_for_component_ref (tree); |
4f588890 | 161 | static int write_dependence_p (const_rtx, const_rtx, int); |
4682ae04 | 162 | |
aa317c97 | 163 | static void memory_modified_1 (rtx, const_rtx, void *); |
9ae8ffe7 JL |
164 | |
165 | /* Set up all info needed to perform alias analysis on memory references. */ | |
166 | ||
d4b60170 | 167 | /* Returns the size in bytes of the mode of X. */ |
9ae8ffe7 JL |
168 | #define SIZE_FOR_MODE(X) (GET_MODE_SIZE (GET_MODE (X))) |
169 | ||
ea64ef27 | 170 | /* Cap the number of passes we make over the insns propagating alias |
131db6b8 SB |
171 | information through set chains. |
172 | ??? 10 is a completely arbitrary choice. This should be based on the | |
173 | maximum loop depth in the CFG, but we do not have this information | |
174 | available (even if current_loops _is_ available). */ | |
ea64ef27 | 175 | #define MAX_ALIAS_LOOP_PASSES 10 |
ca7fd9cd | 176 | |
9ae8ffe7 JL |
177 | /* reg_base_value[N] gives an address to which register N is related. |
178 | If all sets after the first add or subtract to the current value | |
179 | or otherwise modify it so it does not point to a different top level | |
180 | object, reg_base_value[N] is equal to the address part of the source | |
2a2c8203 JC |
181 | of the first set. |
182 | ||
183 | A base address can be an ADDRESS, SYMBOL_REF, or LABEL_REF. ADDRESS | |
9fc37b2b | 184 | expressions represent three types of base: |
b3b5ad95 | 185 | |
9fc37b2b RS |
186 | 1. incoming arguments. There is just one ADDRESS to represent all |
187 | arguments, since we do not know at this level whether accesses | |
188 | based on different arguments can alias. The ADDRESS has id 0. | |
b3b5ad95 | 189 | |
9fc37b2b RS |
190 | 2. stack_pointer_rtx, frame_pointer_rtx, hard_frame_pointer_rtx |
191 | (if distinct from frame_pointer_rtx) and arg_pointer_rtx. | |
192 | Each of these rtxes has a separate ADDRESS associated with it, | |
193 | each with a negative id. | |
194 | ||
195 | GCC is (and is required to be) precise in which register it | |
196 | chooses to access a particular region of stack. We can therefore | |
197 | assume that accesses based on one of these rtxes do not alias | |
198 | accesses based on another of these rtxes. | |
199 | ||
200 | 3. bases that are derived from malloc()ed memory (REG_NOALIAS). | |
201 | Each such piece of memory has a separate ADDRESS associated | |
202 | with it, each with an id greater than 0. | |
203 | ||
204 | Accesses based on one ADDRESS do not alias accesses based on other | |
205 | ADDRESSes. Accesses based on ADDRESSes in groups (2) and (3) do not | |
206 | alias globals either; the ADDRESSes have Pmode to indicate this. | |
207 | The ADDRESS in group (1) _may_ alias globals; it has VOIDmode to | |
208 | indicate this. */ | |
2a2c8203 | 209 | |
08c79682 | 210 | static GTY(()) VEC(rtx,gc) *reg_base_value; |
ac606739 | 211 | static rtx *new_reg_base_value; |
c582d54a | 212 | |
9fc37b2b RS |
213 | /* The single VOIDmode ADDRESS that represents all argument bases. |
214 | It has id 0. */ | |
215 | static GTY(()) rtx arg_base_value; | |
216 | ||
217 | /* Used to allocate unique ids to each REG_NOALIAS ADDRESS. */ | |
218 | static int unique_id; | |
219 | ||
c582d54a JH |
220 | /* We preserve the copy of old array around to avoid amount of garbage |
221 | produced. About 8% of garbage produced were attributed to this | |
222 | array. */ | |
08c79682 | 223 | static GTY((deletable)) VEC(rtx,gc) *old_reg_base_value; |
d4b60170 | 224 | |
9e412ca3 RS |
225 | /* Values of XINT (address, 0) of Pmode ADDRESS rtxes for special |
226 | registers. */ | |
227 | #define UNIQUE_BASE_VALUE_SP -1 | |
228 | #define UNIQUE_BASE_VALUE_ARGP -2 | |
229 | #define UNIQUE_BASE_VALUE_FP -3 | |
230 | #define UNIQUE_BASE_VALUE_HFP -4 | |
231 | ||
7bf84454 RS |
232 | #define static_reg_base_value \ |
233 | (this_target_rtl->x_static_reg_base_value) | |
bf1660a6 | 234 | |
08c79682 KH |
235 | #define REG_BASE_VALUE(X) \ |
236 | (REGNO (X) < VEC_length (rtx, reg_base_value) \ | |
237 | ? VEC_index (rtx, reg_base_value, REGNO (X)) : 0) | |
9ae8ffe7 | 238 | |
c13e8210 | 239 | /* Vector indexed by N giving the initial (unchanging) value known for |
9ff3c7ca | 240 | pseudo-register N. This vector is initialized in init_alias_analysis, |
bb1acb3e | 241 | and does not change until end_alias_analysis is called. */ |
9ff3c7ca | 242 | static GTY(()) VEC(rtx,gc) *reg_known_value; |
9ae8ffe7 JL |
243 | |
244 | /* Vector recording for each reg_known_value whether it is due to a | |
245 | REG_EQUIV note. Future passes (viz., reload) may replace the | |
246 | pseudo with the equivalent expression and so we account for the | |
ac3d9668 RK |
247 | dependences that would be introduced if that happens. |
248 | ||
249 | The REG_EQUIV notes created in assign_parms may mention the arg | |
250 | pointer, and there are explicit insns in the RTL that modify the | |
251 | arg pointer. Thus we must ensure that such insns don't get | |
252 | scheduled across each other because that would invalidate the | |
253 | REG_EQUIV notes. One could argue that the REG_EQUIV notes are | |
254 | wrong, but solving the problem in the scheduler will likely give | |
255 | better code, so we do it here. */ | |
9ff3c7ca | 256 | static sbitmap reg_known_equiv_p; |
9ae8ffe7 | 257 | |
2a2c8203 JC |
258 | /* True when scanning insns from the start of the rtl to the |
259 | NOTE_INSN_FUNCTION_BEG note. */ | |
83bbd9b6 | 260 | static bool copying_arguments; |
9ae8ffe7 | 261 | |
1a5640b4 KH |
262 | DEF_VEC_P(alias_set_entry); |
263 | DEF_VEC_ALLOC_P(alias_set_entry,gc); | |
264 | ||
3932261a | 265 | /* The splay-tree used to store the various alias set entries. */ |
1a5640b4 | 266 | static GTY (()) VEC(alias_set_entry,gc) *alias_sets; |
ac3d9668 | 267 | \f |
55b34b5f RG |
268 | /* Build a decomposed reference object for querying the alias-oracle |
269 | from the MEM rtx and store it in *REF. | |
270 | Returns false if MEM is not suitable for the alias-oracle. */ | |
271 | ||
272 | static bool | |
273 | ao_ref_from_mem (ao_ref *ref, const_rtx mem) | |
274 | { | |
275 | tree expr = MEM_EXPR (mem); | |
276 | tree base; | |
277 | ||
278 | if (!expr) | |
279 | return false; | |
280 | ||
281 | ao_ref_init (ref, expr); | |
282 | ||
283 | /* Get the base of the reference and see if we have to reject or | |
284 | adjust it. */ | |
285 | base = ao_ref_base (ref); | |
286 | if (base == NULL_TREE) | |
287 | return false; | |
288 | ||
366f945f RG |
289 | /* The tree oracle doesn't like to have these. */ |
290 | if (TREE_CODE (base) == FUNCTION_DECL | |
291 | || TREE_CODE (base) == LABEL_DECL) | |
292 | return false; | |
293 | ||
55b34b5f RG |
294 | /* If this is a pointer dereference of a non-SSA_NAME punt. |
295 | ??? We could replace it with a pointer to anything. */ | |
70f34814 RG |
296 | if ((INDIRECT_REF_P (base) |
297 | || TREE_CODE (base) == MEM_REF) | |
55b34b5f RG |
298 | && TREE_CODE (TREE_OPERAND (base, 0)) != SSA_NAME) |
299 | return false; | |
d15adbeb RG |
300 | if (TREE_CODE (base) == TARGET_MEM_REF |
301 | && TMR_BASE (base) | |
302 | && TREE_CODE (TMR_BASE (base)) != SSA_NAME) | |
303 | return false; | |
55b34b5f RG |
304 | |
305 | /* If this is a reference based on a partitioned decl replace the | |
306 | base with an INDIRECT_REF of the pointer representative we | |
307 | created during stack slot partitioning. */ | |
308 | if (TREE_CODE (base) == VAR_DECL | |
309 | && ! TREE_STATIC (base) | |
310 | && cfun->gimple_df->decls_to_pointers != NULL) | |
311 | { | |
312 | void *namep; | |
313 | namep = pointer_map_contains (cfun->gimple_df->decls_to_pointers, base); | |
314 | if (namep) | |
70f34814 | 315 | ref->base = build_simple_mem_ref (*(tree *)namep); |
55b34b5f | 316 | } |
d15adbeb | 317 | else if (TREE_CODE (base) == TARGET_MEM_REF |
4d948885 RG |
318 | && TREE_CODE (TMR_BASE (base)) == ADDR_EXPR |
319 | && TREE_CODE (TREE_OPERAND (TMR_BASE (base), 0)) == VAR_DECL | |
320 | && ! TREE_STATIC (TREE_OPERAND (TMR_BASE (base), 0)) | |
d15adbeb RG |
321 | && cfun->gimple_df->decls_to_pointers != NULL) |
322 | { | |
323 | void *namep; | |
324 | namep = pointer_map_contains (cfun->gimple_df->decls_to_pointers, | |
4d948885 | 325 | TREE_OPERAND (TMR_BASE (base), 0)); |
d15adbeb RG |
326 | if (namep) |
327 | ref->base = build_simple_mem_ref (*(tree *)namep); | |
328 | } | |
55b34b5f RG |
329 | |
330 | ref->ref_alias_set = MEM_ALIAS_SET (mem); | |
331 | ||
f68396a1 RG |
332 | /* If MEM_OFFSET or MEM_SIZE are unknown what we got from MEM_EXPR |
333 | is conservative, so trust it. */ | |
527210c4 | 334 | if (!MEM_OFFSET_KNOWN_P (mem) |
f5541398 | 335 | || !MEM_SIZE_KNOWN_P (mem)) |
f68396a1 | 336 | return true; |
366f945f | 337 | |
b0e96404 RG |
338 | /* If the base decl is a parameter we can have negative MEM_OFFSET in |
339 | case of promoted subregs on bigendian targets. Trust the MEM_EXPR | |
340 | here. */ | |
527210c4 RS |
341 | if (MEM_OFFSET (mem) < 0 |
342 | && (MEM_SIZE (mem) + MEM_OFFSET (mem)) * BITS_PER_UNIT == ref->size) | |
b0e96404 RG |
343 | return true; |
344 | ||
f68396a1 RG |
345 | /* Otherwise continue and refine size and offset we got from analyzing |
346 | MEM_EXPR by using MEM_SIZE and MEM_OFFSET. */ | |
347 | ||
527210c4 | 348 | ref->offset += MEM_OFFSET (mem) * BITS_PER_UNIT; |
f5541398 | 349 | ref->size = MEM_SIZE (mem) * BITS_PER_UNIT; |
b0e96404 RG |
350 | |
351 | /* The MEM may extend into adjacent fields, so adjust max_size if | |
352 | necessary. */ | |
353 | if (ref->max_size != -1 | |
354 | && ref->size > ref->max_size) | |
355 | ref->max_size = ref->size; | |
356 | ||
357 | /* If MEM_OFFSET and MEM_SIZE get us outside of the base object of | |
358 | the MEM_EXPR punt. This happens for STRICT_ALIGNMENT targets a lot. */ | |
359 | if (MEM_EXPR (mem) != get_spill_slot_decl (false) | |
360 | && (ref->offset < 0 | |
361 | || (DECL_P (ref->base) | |
362 | && (!host_integerp (DECL_SIZE (ref->base), 1) | |
363 | || (TREE_INT_CST_LOW (DECL_SIZE ((ref->base))) | |
364 | < (unsigned HOST_WIDE_INT)(ref->offset + ref->size)))))) | |
365 | return false; | |
55b34b5f RG |
366 | |
367 | return true; | |
368 | } | |
369 | ||
370 | /* Query the alias-oracle on whether the two memory rtx X and MEM may | |
371 | alias. If TBAA_P is set also apply TBAA. Returns true if the | |
372 | two rtxen may alias, false otherwise. */ | |
373 | ||
374 | static bool | |
375 | rtx_refs_may_alias_p (const_rtx x, const_rtx mem, bool tbaa_p) | |
376 | { | |
377 | ao_ref ref1, ref2; | |
378 | ||
379 | if (!ao_ref_from_mem (&ref1, x) | |
380 | || !ao_ref_from_mem (&ref2, mem)) | |
381 | return true; | |
382 | ||
55e3bc4c RG |
383 | return refs_may_alias_p_1 (&ref1, &ref2, |
384 | tbaa_p | |
385 | && MEM_ALIAS_SET (x) != 0 | |
386 | && MEM_ALIAS_SET (mem) != 0); | |
55b34b5f RG |
387 | } |
388 | ||
3932261a MM |
389 | /* Returns a pointer to the alias set entry for ALIAS_SET, if there is |
390 | such an entry, or NULL otherwise. */ | |
391 | ||
9ddb66ca | 392 | static inline alias_set_entry |
4862826d | 393 | get_alias_set_entry (alias_set_type alias_set) |
3932261a | 394 | { |
1a5640b4 | 395 | return VEC_index (alias_set_entry, alias_sets, alias_set); |
3932261a MM |
396 | } |
397 | ||
ac3d9668 RK |
398 | /* Returns nonzero if the alias sets for MEM1 and MEM2 are such that |
399 | the two MEMs cannot alias each other. */ | |
3932261a | 400 | |
9ddb66ca | 401 | static inline int |
4f588890 | 402 | mems_in_disjoint_alias_sets_p (const_rtx mem1, const_rtx mem2) |
3932261a | 403 | { |
3932261a MM |
404 | /* Perform a basic sanity check. Namely, that there are no alias sets |
405 | if we're not using strict aliasing. This helps to catch bugs | |
406 | whereby someone uses PUT_CODE, but doesn't clear MEM_ALIAS_SET, or | |
407 | where a MEM is allocated in some way other than by the use of | |
408 | gen_rtx_MEM, and the MEM_ALIAS_SET is not cleared. If we begin to | |
409 | use alias sets to indicate that spilled registers cannot alias each | |
410 | other, we might need to remove this check. */ | |
298e6adc NS |
411 | gcc_assert (flag_strict_aliasing |
412 | || (!MEM_ALIAS_SET (mem1) && !MEM_ALIAS_SET (mem2))); | |
3932261a | 413 | |
1da68f56 RK |
414 | return ! alias_sets_conflict_p (MEM_ALIAS_SET (mem1), MEM_ALIAS_SET (mem2)); |
415 | } | |
3932261a | 416 | |
1da68f56 RK |
417 | /* Insert the NODE into the splay tree given by DATA. Used by |
418 | record_alias_subset via splay_tree_foreach. */ | |
419 | ||
420 | static int | |
4682ae04 | 421 | insert_subset_children (splay_tree_node node, void *data) |
1da68f56 RK |
422 | { |
423 | splay_tree_insert ((splay_tree) data, node->key, node->value); | |
424 | ||
425 | return 0; | |
426 | } | |
427 | ||
c58936b6 DB |
428 | /* Return true if the first alias set is a subset of the second. */ |
429 | ||
430 | bool | |
4862826d | 431 | alias_set_subset_of (alias_set_type set1, alias_set_type set2) |
c58936b6 DB |
432 | { |
433 | alias_set_entry ase; | |
434 | ||
435 | /* Everything is a subset of the "aliases everything" set. */ | |
436 | if (set2 == 0) | |
437 | return true; | |
438 | ||
439 | /* Otherwise, check if set1 is a subset of set2. */ | |
440 | ase = get_alias_set_entry (set2); | |
441 | if (ase != 0 | |
038a39d1 | 442 | && (ase->has_zero_child |
a7a512be RG |
443 | || splay_tree_lookup (ase->children, |
444 | (splay_tree_key) set1))) | |
c58936b6 DB |
445 | return true; |
446 | return false; | |
447 | } | |
448 | ||
1da68f56 RK |
449 | /* Return 1 if the two specified alias sets may conflict. */ |
450 | ||
451 | int | |
4862826d | 452 | alias_sets_conflict_p (alias_set_type set1, alias_set_type set2) |
1da68f56 RK |
453 | { |
454 | alias_set_entry ase; | |
455 | ||
836f7794 EB |
456 | /* The easy case. */ |
457 | if (alias_sets_must_conflict_p (set1, set2)) | |
1da68f56 | 458 | return 1; |
3932261a | 459 | |
3bdf5ad1 | 460 | /* See if the first alias set is a subset of the second. */ |
1da68f56 | 461 | ase = get_alias_set_entry (set1); |
2bf105ab RK |
462 | if (ase != 0 |
463 | && (ase->has_zero_child | |
464 | || splay_tree_lookup (ase->children, | |
1da68f56 RK |
465 | (splay_tree_key) set2))) |
466 | return 1; | |
3932261a MM |
467 | |
468 | /* Now do the same, but with the alias sets reversed. */ | |
1da68f56 | 469 | ase = get_alias_set_entry (set2); |
2bf105ab RK |
470 | if (ase != 0 |
471 | && (ase->has_zero_child | |
472 | || splay_tree_lookup (ase->children, | |
1da68f56 RK |
473 | (splay_tree_key) set1))) |
474 | return 1; | |
3932261a | 475 | |
1da68f56 | 476 | /* The two alias sets are distinct and neither one is the |
836f7794 | 477 | child of the other. Therefore, they cannot conflict. */ |
1da68f56 | 478 | return 0; |
3932261a | 479 | } |
5399d643 | 480 | |
836f7794 | 481 | /* Return 1 if the two specified alias sets will always conflict. */ |
5399d643 JW |
482 | |
483 | int | |
4862826d | 484 | alias_sets_must_conflict_p (alias_set_type set1, alias_set_type set2) |
5399d643 JW |
485 | { |
486 | if (set1 == 0 || set2 == 0 || set1 == set2) | |
487 | return 1; | |
488 | ||
489 | return 0; | |
490 | } | |
491 | ||
1da68f56 RK |
492 | /* Return 1 if any MEM object of type T1 will always conflict (using the |
493 | dependency routines in this file) with any MEM object of type T2. | |
494 | This is used when allocating temporary storage. If T1 and/or T2 are | |
495 | NULL_TREE, it means we know nothing about the storage. */ | |
496 | ||
497 | int | |
4682ae04 | 498 | objects_must_conflict_p (tree t1, tree t2) |
1da68f56 | 499 | { |
4862826d | 500 | alias_set_type set1, set2; |
82d610ec | 501 | |
e8ea2809 RK |
502 | /* If neither has a type specified, we don't know if they'll conflict |
503 | because we may be using them to store objects of various types, for | |
504 | example the argument and local variables areas of inlined functions. */ | |
981a4c34 | 505 | if (t1 == 0 && t2 == 0) |
e8ea2809 RK |
506 | return 0; |
507 | ||
1da68f56 RK |
508 | /* If they are the same type, they must conflict. */ |
509 | if (t1 == t2 | |
510 | /* Likewise if both are volatile. */ | |
511 | || (t1 != 0 && TYPE_VOLATILE (t1) && t2 != 0 && TYPE_VOLATILE (t2))) | |
512 | return 1; | |
513 | ||
82d610ec RK |
514 | set1 = t1 ? get_alias_set (t1) : 0; |
515 | set2 = t2 ? get_alias_set (t2) : 0; | |
1da68f56 | 516 | |
836f7794 EB |
517 | /* We can't use alias_sets_conflict_p because we must make sure |
518 | that every subtype of t1 will conflict with every subtype of | |
82d610ec RK |
519 | t2 for which a pair of subobjects of these respective subtypes |
520 | overlaps on the stack. */ | |
836f7794 | 521 | return alias_sets_must_conflict_p (set1, set2); |
1da68f56 RK |
522 | } |
523 | \f | |
2039d7aa RH |
524 | /* Return true if all nested component references handled by |
525 | get_inner_reference in T are such that we should use the alias set | |
526 | provided by the object at the heart of T. | |
527 | ||
528 | This is true for non-addressable components (which don't have their | |
529 | own alias set), as well as components of objects in alias set zero. | |
530 | This later point is a special case wherein we wish to override the | |
531 | alias set used by the component, but we don't have per-FIELD_DECL | |
532 | assignable alias sets. */ | |
533 | ||
534 | bool | |
22ea9ec0 | 535 | component_uses_parent_alias_set (const_tree t) |
6e24b709 | 536 | { |
afe84921 RH |
537 | while (1) |
538 | { | |
2039d7aa | 539 | /* If we're at the end, it vacuously uses its own alias set. */ |
afe84921 | 540 | if (!handled_component_p (t)) |
2039d7aa | 541 | return false; |
afe84921 RH |
542 | |
543 | switch (TREE_CODE (t)) | |
544 | { | |
545 | case COMPONENT_REF: | |
546 | if (DECL_NONADDRESSABLE_P (TREE_OPERAND (t, 1))) | |
2039d7aa | 547 | return true; |
afe84921 RH |
548 | break; |
549 | ||
550 | case ARRAY_REF: | |
551 | case ARRAY_RANGE_REF: | |
552 | if (TYPE_NONALIASED_COMPONENT (TREE_TYPE (TREE_OPERAND (t, 0)))) | |
2039d7aa | 553 | return true; |
afe84921 RH |
554 | break; |
555 | ||
556 | case REALPART_EXPR: | |
557 | case IMAGPART_EXPR: | |
558 | break; | |
559 | ||
560 | default: | |
561 | /* Bitfields and casts are never addressable. */ | |
2039d7aa | 562 | return true; |
afe84921 RH |
563 | } |
564 | ||
565 | t = TREE_OPERAND (t, 0); | |
2039d7aa RH |
566 | if (get_alias_set (TREE_TYPE (t)) == 0) |
567 | return true; | |
afe84921 | 568 | } |
6e24b709 RK |
569 | } |
570 | ||
5006671f RG |
571 | /* Return the alias set for the memory pointed to by T, which may be |
572 | either a type or an expression. Return -1 if there is nothing | |
573 | special about dereferencing T. */ | |
574 | ||
575 | static alias_set_type | |
576 | get_deref_alias_set_1 (tree t) | |
577 | { | |
578 | /* If we're not doing any alias analysis, just assume everything | |
579 | aliases everything else. */ | |
580 | if (!flag_strict_aliasing) | |
581 | return 0; | |
582 | ||
5b21f0f3 | 583 | /* All we care about is the type. */ |
5006671f | 584 | if (! TYPE_P (t)) |
5b21f0f3 | 585 | t = TREE_TYPE (t); |
5006671f RG |
586 | |
587 | /* If we have an INDIRECT_REF via a void pointer, we don't | |
588 | know anything about what that might alias. Likewise if the | |
589 | pointer is marked that way. */ | |
590 | if (TREE_CODE (TREE_TYPE (t)) == VOID_TYPE | |
591 | || TYPE_REF_CAN_ALIAS_ALL (t)) | |
592 | return 0; | |
593 | ||
594 | return -1; | |
595 | } | |
596 | ||
597 | /* Return the alias set for the memory pointed to by T, which may be | |
598 | either a type or an expression. */ | |
599 | ||
600 | alias_set_type | |
601 | get_deref_alias_set (tree t) | |
602 | { | |
603 | alias_set_type set = get_deref_alias_set_1 (t); | |
604 | ||
605 | /* Fall back to the alias-set of the pointed-to type. */ | |
606 | if (set == -1) | |
607 | { | |
608 | if (! TYPE_P (t)) | |
609 | t = TREE_TYPE (t); | |
610 | set = get_alias_set (TREE_TYPE (t)); | |
611 | } | |
612 | ||
613 | return set; | |
614 | } | |
615 | ||
3bdf5ad1 RK |
616 | /* Return the alias set for T, which may be either a type or an |
617 | expression. Call language-specific routine for help, if needed. */ | |
618 | ||
4862826d | 619 | alias_set_type |
4682ae04 | 620 | get_alias_set (tree t) |
3bdf5ad1 | 621 | { |
4862826d | 622 | alias_set_type set; |
3bdf5ad1 RK |
623 | |
624 | /* If we're not doing any alias analysis, just assume everything | |
625 | aliases everything else. Also return 0 if this or its type is | |
626 | an error. */ | |
627 | if (! flag_strict_aliasing || t == error_mark_node | |
628 | || (! TYPE_P (t) | |
629 | && (TREE_TYPE (t) == 0 || TREE_TYPE (t) == error_mark_node))) | |
630 | return 0; | |
631 | ||
632 | /* We can be passed either an expression or a type. This and the | |
f47e9b4e RK |
633 | language-specific routine may make mutually-recursive calls to each other |
634 | to figure out what to do. At each juncture, we see if this is a tree | |
635 | that the language may need to handle specially. First handle things that | |
738cc472 | 636 | aren't types. */ |
f824e5c3 | 637 | if (! TYPE_P (t)) |
3bdf5ad1 | 638 | { |
ebcc3d93 | 639 | tree inner; |
738cc472 | 640 | |
70f34814 RG |
641 | /* Give the language a chance to do something with this tree |
642 | before we look at it. */ | |
8ac61af7 | 643 | STRIP_NOPS (t); |
ae2bcd98 | 644 | set = lang_hooks.get_alias_set (t); |
8ac61af7 RK |
645 | if (set != -1) |
646 | return set; | |
647 | ||
70f34814 | 648 | /* Get the base object of the reference. */ |
ebcc3d93 | 649 | inner = t; |
6fce44af | 650 | while (handled_component_p (inner)) |
738cc472 | 651 | { |
70f34814 RG |
652 | /* If there is a VIEW_CONVERT_EXPR in the chain we cannot use |
653 | the type of any component references that wrap it to | |
654 | determine the alias-set. */ | |
655 | if (TREE_CODE (inner) == VIEW_CONVERT_EXPR) | |
656 | t = TREE_OPERAND (inner, 0); | |
6fce44af | 657 | inner = TREE_OPERAND (inner, 0); |
738cc472 RK |
658 | } |
659 | ||
70f34814 RG |
660 | /* Handle pointer dereferences here, they can override the |
661 | alias-set. */ | |
1b096a0a | 662 | if (INDIRECT_REF_P (inner)) |
738cc472 | 663 | { |
5006671f RG |
664 | set = get_deref_alias_set_1 (TREE_OPERAND (inner, 0)); |
665 | if (set != -1) | |
666 | return set; | |
738cc472 | 667 | } |
4b228e61 RG |
668 | else if (TREE_CODE (inner) == TARGET_MEM_REF) |
669 | return get_deref_alias_set (TMR_OFFSET (inner)); | |
70f34814 RG |
670 | else if (TREE_CODE (inner) == MEM_REF) |
671 | { | |
672 | set = get_deref_alias_set_1 (TREE_OPERAND (inner, 1)); | |
673 | if (set != -1) | |
674 | return set; | |
675 | } | |
676 | ||
677 | /* If the innermost reference is a MEM_REF that has a | |
678 | conversion embedded treat it like a VIEW_CONVERT_EXPR above, | |
679 | using the memory access type for determining the alias-set. */ | |
680 | if (TREE_CODE (inner) == MEM_REF | |
7be7d292 EB |
681 | && TYPE_MAIN_VARIANT (TREE_TYPE (inner)) |
682 | != TYPE_MAIN_VARIANT | |
683 | (TREE_TYPE (TREE_TYPE (TREE_OPERAND (inner, 1))))) | |
70f34814 | 684 | return get_deref_alias_set (TREE_OPERAND (inner, 1)); |
738cc472 RK |
685 | |
686 | /* Otherwise, pick up the outermost object that we could have a pointer | |
6fce44af | 687 | to, processing conversions as above. */ |
2039d7aa | 688 | while (component_uses_parent_alias_set (t)) |
f47e9b4e | 689 | { |
6fce44af | 690 | t = TREE_OPERAND (t, 0); |
8ac61af7 RK |
691 | STRIP_NOPS (t); |
692 | } | |
f824e5c3 | 693 | |
738cc472 RK |
694 | /* If we've already determined the alias set for a decl, just return |
695 | it. This is necessary for C++ anonymous unions, whose component | |
696 | variables don't look like union members (boo!). */ | |
5755cd38 | 697 | if (TREE_CODE (t) == VAR_DECL |
3c0cb5de | 698 | && DECL_RTL_SET_P (t) && MEM_P (DECL_RTL (t))) |
5755cd38 JM |
699 | return MEM_ALIAS_SET (DECL_RTL (t)); |
700 | ||
f824e5c3 RK |
701 | /* Now all we care about is the type. */ |
702 | t = TREE_TYPE (t); | |
3bdf5ad1 RK |
703 | } |
704 | ||
3bdf5ad1 | 705 | /* Variant qualifiers don't affect the alias set, so get the main |
daad0278 | 706 | variant. */ |
3bdf5ad1 | 707 | t = TYPE_MAIN_VARIANT (t); |
daad0278 RG |
708 | |
709 | /* Always use the canonical type as well. If this is a type that | |
710 | requires structural comparisons to identify compatible types | |
711 | use alias set zero. */ | |
712 | if (TYPE_STRUCTURAL_EQUALITY_P (t)) | |
cb9c2485 JM |
713 | { |
714 | /* Allow the language to specify another alias set for this | |
715 | type. */ | |
716 | set = lang_hooks.get_alias_set (t); | |
717 | if (set != -1) | |
718 | return set; | |
719 | return 0; | |
720 | } | |
7be7d292 | 721 | |
daad0278 | 722 | t = TYPE_CANONICAL (t); |
7be7d292 | 723 | |
96d91dcf RG |
724 | /* The canonical type should not require structural equality checks. */ |
725 | gcc_checking_assert (!TYPE_STRUCTURAL_EQUALITY_P (t)); | |
daad0278 RG |
726 | |
727 | /* If this is a type with a known alias set, return it. */ | |
738cc472 | 728 | if (TYPE_ALIAS_SET_KNOWN_P (t)) |
3bdf5ad1 RK |
729 | return TYPE_ALIAS_SET (t); |
730 | ||
36784d0e RG |
731 | /* We don't want to set TYPE_ALIAS_SET for incomplete types. */ |
732 | if (!COMPLETE_TYPE_P (t)) | |
733 | { | |
734 | /* For arrays with unknown size the conservative answer is the | |
735 | alias set of the element type. */ | |
736 | if (TREE_CODE (t) == ARRAY_TYPE) | |
737 | return get_alias_set (TREE_TYPE (t)); | |
738 | ||
739 | /* But return zero as a conservative answer for incomplete types. */ | |
740 | return 0; | |
741 | } | |
742 | ||
3bdf5ad1 | 743 | /* See if the language has special handling for this type. */ |
ae2bcd98 | 744 | set = lang_hooks.get_alias_set (t); |
8ac61af7 | 745 | if (set != -1) |
738cc472 | 746 | return set; |
2bf105ab | 747 | |
3bdf5ad1 RK |
748 | /* There are no objects of FUNCTION_TYPE, so there's no point in |
749 | using up an alias set for them. (There are, of course, pointers | |
750 | and references to functions, but that's different.) */ | |
7be7d292 | 751 | else if (TREE_CODE (t) == FUNCTION_TYPE || TREE_CODE (t) == METHOD_TYPE) |
3bdf5ad1 | 752 | set = 0; |
74d86f4f RH |
753 | |
754 | /* Unless the language specifies otherwise, let vector types alias | |
755 | their components. This avoids some nasty type punning issues in | |
756 | normal usage. And indeed lets vectors be treated more like an | |
757 | array slice. */ | |
758 | else if (TREE_CODE (t) == VECTOR_TYPE) | |
759 | set = get_alias_set (TREE_TYPE (t)); | |
760 | ||
4653cae5 RG |
761 | /* Unless the language specifies otherwise, treat array types the |
762 | same as their components. This avoids the asymmetry we get | |
763 | through recording the components. Consider accessing a | |
764 | character(kind=1) through a reference to a character(kind=1)[1:1]. | |
765 | Or consider if we want to assign integer(kind=4)[0:D.1387] and | |
766 | integer(kind=4)[4] the same alias set or not. | |
767 | Just be pragmatic here and make sure the array and its element | |
768 | type get the same alias set assigned. */ | |
7be7d292 | 769 | else if (TREE_CODE (t) == ARRAY_TYPE && !TYPE_NONALIASED_COMPONENT (t)) |
4653cae5 RG |
770 | set = get_alias_set (TREE_TYPE (t)); |
771 | ||
0ceb0201 RG |
772 | /* From the former common C and C++ langhook implementation: |
773 | ||
774 | Unfortunately, there is no canonical form of a pointer type. | |
775 | In particular, if we have `typedef int I', then `int *', and | |
776 | `I *' are different types. So, we have to pick a canonical | |
777 | representative. We do this below. | |
778 | ||
779 | Technically, this approach is actually more conservative that | |
780 | it needs to be. In particular, `const int *' and `int *' | |
781 | should be in different alias sets, according to the C and C++ | |
782 | standard, since their types are not the same, and so, | |
783 | technically, an `int **' and `const int **' cannot point at | |
784 | the same thing. | |
785 | ||
786 | But, the standard is wrong. In particular, this code is | |
787 | legal C++: | |
788 | ||
789 | int *ip; | |
790 | int **ipp = &ip; | |
791 | const int* const* cipp = ipp; | |
792 | And, it doesn't make sense for that to be legal unless you | |
793 | can dereference IPP and CIPP. So, we ignore cv-qualifiers on | |
794 | the pointed-to types. This issue has been reported to the | |
795 | C++ committee. | |
796 | ||
797 | In addition to the above canonicalization issue, with LTO | |
798 | we should also canonicalize `T (*)[]' to `T *' avoiding | |
799 | alias issues with pointer-to element types and pointer-to | |
800 | array types. | |
801 | ||
802 | Likewise we need to deal with the situation of incomplete | |
803 | pointed-to types and make `*(struct X **)&a' and | |
804 | `*(struct X {} **)&a' alias. Otherwise we will have to | |
805 | guarantee that all pointer-to incomplete type variants | |
806 | will be replaced by pointer-to complete type variants if | |
807 | they are available. | |
808 | ||
809 | With LTO the convenient situation of using `void *' to | |
810 | access and store any pointer type will also become | |
811 | more apparent (and `void *' is just another pointer-to | |
812 | incomplete type). Assigning alias-set zero to `void *' | |
813 | and all pointer-to incomplete types is a not appealing | |
814 | solution. Assigning an effective alias-set zero only | |
815 | affecting pointers might be - by recording proper subset | |
816 | relationships of all pointer alias-sets. | |
817 | ||
818 | Pointer-to function types are another grey area which | |
819 | needs caution. Globbing them all into one alias-set | |
820 | or the above effective zero set would work. | |
821 | ||
822 | For now just assign the same alias-set to all pointers. | |
823 | That's simple and avoids all the above problems. */ | |
824 | else if (POINTER_TYPE_P (t) | |
825 | && t != ptr_type_node) | |
96d91dcf | 826 | set = get_alias_set (ptr_type_node); |
0ceb0201 | 827 | |
7be7d292 | 828 | /* Otherwise make a new alias set for this type. */ |
3bdf5ad1 | 829 | else |
96d91dcf RG |
830 | { |
831 | /* Each canonical type gets its own alias set, so canonical types | |
832 | shouldn't form a tree. It doesn't really matter for types | |
833 | we handle specially above, so only check it where it possibly | |
834 | would result in a bogus alias set. */ | |
835 | gcc_checking_assert (TYPE_CANONICAL (t) == t); | |
836 | ||
837 | set = new_alias_set (); | |
838 | } | |
3bdf5ad1 RK |
839 | |
840 | TYPE_ALIAS_SET (t) = set; | |
2bf105ab | 841 | |
7be7d292 EB |
842 | /* If this is an aggregate type or a complex type, we must record any |
843 | component aliasing information. */ | |
1d79fd2c | 844 | if (AGGREGATE_TYPE_P (t) || TREE_CODE (t) == COMPLEX_TYPE) |
2bf105ab RK |
845 | record_component_aliases (t); |
846 | ||
3bdf5ad1 RK |
847 | return set; |
848 | } | |
849 | ||
850 | /* Return a brand-new alias set. */ | |
851 | ||
4862826d | 852 | alias_set_type |
4682ae04 | 853 | new_alias_set (void) |
3bdf5ad1 | 854 | { |
3bdf5ad1 | 855 | if (flag_strict_aliasing) |
9ddb66ca | 856 | { |
1a5640b4 | 857 | if (alias_sets == 0) |
f32682ca DN |
858 | VEC_safe_push (alias_set_entry, gc, alias_sets, 0); |
859 | VEC_safe_push (alias_set_entry, gc, alias_sets, 0); | |
1a5640b4 | 860 | return VEC_length (alias_set_entry, alias_sets) - 1; |
9ddb66ca | 861 | } |
3bdf5ad1 RK |
862 | else |
863 | return 0; | |
864 | } | |
3932261a | 865 | |
01d28c3f JM |
866 | /* Indicate that things in SUBSET can alias things in SUPERSET, but that |
867 | not everything that aliases SUPERSET also aliases SUBSET. For example, | |
868 | in C, a store to an `int' can alias a load of a structure containing an | |
869 | `int', and vice versa. But it can't alias a load of a 'double' member | |
870 | of the same structure. Here, the structure would be the SUPERSET and | |
871 | `int' the SUBSET. This relationship is also described in the comment at | |
872 | the beginning of this file. | |
873 | ||
874 | This function should be called only once per SUPERSET/SUBSET pair. | |
3932261a MM |
875 | |
876 | It is illegal for SUPERSET to be zero; everything is implicitly a | |
877 | subset of alias set zero. */ | |
878 | ||
794511d2 | 879 | void |
4862826d | 880 | record_alias_subset (alias_set_type superset, alias_set_type subset) |
3932261a MM |
881 | { |
882 | alias_set_entry superset_entry; | |
883 | alias_set_entry subset_entry; | |
884 | ||
f47e9b4e RK |
885 | /* It is possible in complex type situations for both sets to be the same, |
886 | in which case we can ignore this operation. */ | |
887 | if (superset == subset) | |
888 | return; | |
889 | ||
298e6adc | 890 | gcc_assert (superset); |
3932261a MM |
891 | |
892 | superset_entry = get_alias_set_entry (superset); | |
ca7fd9cd | 893 | if (superset_entry == 0) |
3932261a MM |
894 | { |
895 | /* Create an entry for the SUPERSET, so that we have a place to | |
896 | attach the SUBSET. */ | |
a9429e29 | 897 | superset_entry = ggc_alloc_cleared_alias_set_entry_d (); |
3932261a | 898 | superset_entry->alias_set = superset; |
ca7fd9cd | 899 | superset_entry->children |
a9429e29 LB |
900 | = splay_tree_new_ggc (splay_tree_compare_ints, |
901 | ggc_alloc_splay_tree_scalar_scalar_splay_tree_s, | |
902 | ggc_alloc_splay_tree_scalar_scalar_splay_tree_node_s); | |
570eb5c8 | 903 | superset_entry->has_zero_child = 0; |
1a5640b4 | 904 | VEC_replace (alias_set_entry, alias_sets, superset, superset_entry); |
3932261a MM |
905 | } |
906 | ||
2bf105ab RK |
907 | if (subset == 0) |
908 | superset_entry->has_zero_child = 1; | |
909 | else | |
910 | { | |
911 | subset_entry = get_alias_set_entry (subset); | |
912 | /* If there is an entry for the subset, enter all of its children | |
913 | (if they are not already present) as children of the SUPERSET. */ | |
ca7fd9cd | 914 | if (subset_entry) |
2bf105ab RK |
915 | { |
916 | if (subset_entry->has_zero_child) | |
917 | superset_entry->has_zero_child = 1; | |
d4b60170 | 918 | |
2bf105ab RK |
919 | splay_tree_foreach (subset_entry->children, insert_subset_children, |
920 | superset_entry->children); | |
921 | } | |
3932261a | 922 | |
2bf105ab | 923 | /* Enter the SUBSET itself as a child of the SUPERSET. */ |
ca7fd9cd | 924 | splay_tree_insert (superset_entry->children, |
2bf105ab RK |
925 | (splay_tree_key) subset, 0); |
926 | } | |
3932261a MM |
927 | } |
928 | ||
a0c33338 RK |
929 | /* Record that component types of TYPE, if any, are part of that type for |
930 | aliasing purposes. For record types, we only record component types | |
b5487346 EB |
931 | for fields that are not marked non-addressable. For array types, we |
932 | only record the component type if it is not marked non-aliased. */ | |
a0c33338 RK |
933 | |
934 | void | |
4682ae04 | 935 | record_component_aliases (tree type) |
a0c33338 | 936 | { |
4862826d | 937 | alias_set_type superset = get_alias_set (type); |
a0c33338 RK |
938 | tree field; |
939 | ||
940 | if (superset == 0) | |
941 | return; | |
942 | ||
943 | switch (TREE_CODE (type)) | |
944 | { | |
a0c33338 RK |
945 | case RECORD_TYPE: |
946 | case UNION_TYPE: | |
947 | case QUAL_UNION_TYPE: | |
6614fd40 | 948 | /* Recursively record aliases for the base classes, if there are any. */ |
fa743e8c | 949 | if (TYPE_BINFO (type)) |
ca7fd9cd KH |
950 | { |
951 | int i; | |
fa743e8c | 952 | tree binfo, base_binfo; |
c22cacf3 | 953 | |
fa743e8c NS |
954 | for (binfo = TYPE_BINFO (type), i = 0; |
955 | BINFO_BASE_ITERATE (binfo, i, base_binfo); i++) | |
956 | record_alias_subset (superset, | |
957 | get_alias_set (BINFO_TYPE (base_binfo))); | |
ca7fd9cd | 958 | } |
910ad8de | 959 | for (field = TYPE_FIELDS (type); field != 0; field = DECL_CHAIN (field)) |
b5487346 | 960 | if (TREE_CODE (field) == FIELD_DECL && !DECL_NONADDRESSABLE_P (field)) |
2bf105ab | 961 | record_alias_subset (superset, get_alias_set (TREE_TYPE (field))); |
a0c33338 RK |
962 | break; |
963 | ||
1d79fd2c JW |
964 | case COMPLEX_TYPE: |
965 | record_alias_subset (superset, get_alias_set (TREE_TYPE (type))); | |
966 | break; | |
967 | ||
4653cae5 RG |
968 | /* VECTOR_TYPE and ARRAY_TYPE share the alias set with their |
969 | element type. */ | |
970 | ||
a0c33338 RK |
971 | default: |
972 | break; | |
973 | } | |
974 | } | |
975 | ||
3bdf5ad1 RK |
976 | /* Allocate an alias set for use in storing and reading from the varargs |
977 | spill area. */ | |
978 | ||
4862826d | 979 | static GTY(()) alias_set_type varargs_set = -1; |
f103e34d | 980 | |
4862826d | 981 | alias_set_type |
4682ae04 | 982 | get_varargs_alias_set (void) |
3bdf5ad1 | 983 | { |
cd3ce9b4 JM |
984 | #if 1 |
985 | /* We now lower VA_ARG_EXPR, and there's currently no way to attach the | |
986 | varargs alias set to an INDIRECT_REF (FIXME!), so we can't | |
987 | consistently use the varargs alias set for loads from the varargs | |
988 | area. So don't use it anywhere. */ | |
989 | return 0; | |
990 | #else | |
f103e34d GK |
991 | if (varargs_set == -1) |
992 | varargs_set = new_alias_set (); | |
3bdf5ad1 | 993 | |
f103e34d | 994 | return varargs_set; |
cd3ce9b4 | 995 | #endif |
3bdf5ad1 RK |
996 | } |
997 | ||
998 | /* Likewise, but used for the fixed portions of the frame, e.g., register | |
999 | save areas. */ | |
1000 | ||
4862826d | 1001 | static GTY(()) alias_set_type frame_set = -1; |
f103e34d | 1002 | |
4862826d | 1003 | alias_set_type |
4682ae04 | 1004 | get_frame_alias_set (void) |
3bdf5ad1 | 1005 | { |
f103e34d GK |
1006 | if (frame_set == -1) |
1007 | frame_set = new_alias_set (); | |
3bdf5ad1 | 1008 | |
f103e34d | 1009 | return frame_set; |
3bdf5ad1 RK |
1010 | } |
1011 | ||
9fc37b2b RS |
1012 | /* Create a new, unique base with id ID. */ |
1013 | ||
1014 | static rtx | |
1015 | unique_base_value (HOST_WIDE_INT id) | |
1016 | { | |
1017 | return gen_rtx_ADDRESS (Pmode, id); | |
1018 | } | |
1019 | ||
1020 | /* Return true if accesses based on any other base value cannot alias | |
1021 | those based on X. */ | |
1022 | ||
1023 | static bool | |
1024 | unique_base_value_p (rtx x) | |
1025 | { | |
1026 | return GET_CODE (x) == ADDRESS && GET_MODE (x) == Pmode; | |
1027 | } | |
1028 | ||
1029 | /* Return true if X is known to be a base value. */ | |
1030 | ||
1031 | static bool | |
1032 | known_base_value_p (rtx x) | |
1033 | { | |
1034 | switch (GET_CODE (x)) | |
1035 | { | |
1036 | case LABEL_REF: | |
1037 | case SYMBOL_REF: | |
1038 | return true; | |
1039 | ||
1040 | case ADDRESS: | |
1041 | /* Arguments may or may not be bases; we don't know for sure. */ | |
1042 | return GET_MODE (x) != VOIDmode; | |
1043 | ||
1044 | default: | |
1045 | return false; | |
1046 | } | |
1047 | } | |
1048 | ||
2a2c8203 JC |
1049 | /* Inside SRC, the source of a SET, find a base address. */ |
1050 | ||
9ae8ffe7 | 1051 | static rtx |
4682ae04 | 1052 | find_base_value (rtx src) |
9ae8ffe7 | 1053 | { |
713f41f9 | 1054 | unsigned int regno; |
0aacc8ed | 1055 | |
53451050 RS |
1056 | #if defined (FIND_BASE_TERM) |
1057 | /* Try machine-dependent ways to find the base term. */ | |
1058 | src = FIND_BASE_TERM (src); | |
1059 | #endif | |
1060 | ||
9ae8ffe7 JL |
1061 | switch (GET_CODE (src)) |
1062 | { | |
1063 | case SYMBOL_REF: | |
1064 | case LABEL_REF: | |
1065 | return src; | |
1066 | ||
1067 | case REG: | |
fb6754f0 | 1068 | regno = REGNO (src); |
d4b60170 | 1069 | /* At the start of a function, argument registers have known base |
2a2c8203 JC |
1070 | values which may be lost later. Returning an ADDRESS |
1071 | expression here allows optimization based on argument values | |
1072 | even when the argument registers are used for other purposes. */ | |
713f41f9 BS |
1073 | if (regno < FIRST_PSEUDO_REGISTER && copying_arguments) |
1074 | return new_reg_base_value[regno]; | |
73774bc7 | 1075 | |
eaf407a5 | 1076 | /* If a pseudo has a known base value, return it. Do not do this |
9b462c42 RH |
1077 | for non-fixed hard regs since it can result in a circular |
1078 | dependency chain for registers which have values at function entry. | |
eaf407a5 JL |
1079 | |
1080 | The test above is not sufficient because the scheduler may move | |
1081 | a copy out of an arg reg past the NOTE_INSN_FUNCTION_BEGIN. */ | |
9b462c42 | 1082 | if ((regno >= FIRST_PSEUDO_REGISTER || fixed_regs[regno]) |
08c79682 | 1083 | && regno < VEC_length (rtx, reg_base_value)) |
83bbd9b6 RH |
1084 | { |
1085 | /* If we're inside init_alias_analysis, use new_reg_base_value | |
1086 | to reduce the number of relaxation iterations. */ | |
1afdf91c | 1087 | if (new_reg_base_value && new_reg_base_value[regno] |
6fb5fa3c | 1088 | && DF_REG_DEF_COUNT (regno) == 1) |
83bbd9b6 RH |
1089 | return new_reg_base_value[regno]; |
1090 | ||
08c79682 KH |
1091 | if (VEC_index (rtx, reg_base_value, regno)) |
1092 | return VEC_index (rtx, reg_base_value, regno); | |
83bbd9b6 | 1093 | } |
73774bc7 | 1094 | |
e3f049a8 | 1095 | return 0; |
9ae8ffe7 JL |
1096 | |
1097 | case MEM: | |
1098 | /* Check for an argument passed in memory. Only record in the | |
1099 | copying-arguments block; it is too hard to track changes | |
1100 | otherwise. */ | |
1101 | if (copying_arguments | |
1102 | && (XEXP (src, 0) == arg_pointer_rtx | |
1103 | || (GET_CODE (XEXP (src, 0)) == PLUS | |
1104 | && XEXP (XEXP (src, 0), 0) == arg_pointer_rtx))) | |
9fc37b2b | 1105 | return arg_base_value; |
9ae8ffe7 JL |
1106 | return 0; |
1107 | ||
1108 | case CONST: | |
1109 | src = XEXP (src, 0); | |
1110 | if (GET_CODE (src) != PLUS && GET_CODE (src) != MINUS) | |
1111 | break; | |
d4b60170 | 1112 | |
ec5c56db | 1113 | /* ... fall through ... */ |
2a2c8203 | 1114 | |
9ae8ffe7 JL |
1115 | case PLUS: |
1116 | case MINUS: | |
2a2c8203 | 1117 | { |
ec907dd8 JL |
1118 | rtx temp, src_0 = XEXP (src, 0), src_1 = XEXP (src, 1); |
1119 | ||
0134bf2d DE |
1120 | /* If either operand is a REG that is a known pointer, then it |
1121 | is the base. */ | |
1122 | if (REG_P (src_0) && REG_POINTER (src_0)) | |
1123 | return find_base_value (src_0); | |
1124 | if (REG_P (src_1) && REG_POINTER (src_1)) | |
1125 | return find_base_value (src_1); | |
1126 | ||
ec907dd8 JL |
1127 | /* If either operand is a REG, then see if we already have |
1128 | a known value for it. */ | |
0134bf2d | 1129 | if (REG_P (src_0)) |
ec907dd8 JL |
1130 | { |
1131 | temp = find_base_value (src_0); | |
d4b60170 | 1132 | if (temp != 0) |
ec907dd8 JL |
1133 | src_0 = temp; |
1134 | } | |
1135 | ||
0134bf2d | 1136 | if (REG_P (src_1)) |
ec907dd8 JL |
1137 | { |
1138 | temp = find_base_value (src_1); | |
d4b60170 | 1139 | if (temp!= 0) |
ec907dd8 JL |
1140 | src_1 = temp; |
1141 | } | |
2a2c8203 | 1142 | |
0134bf2d DE |
1143 | /* If either base is named object or a special address |
1144 | (like an argument or stack reference), then use it for the | |
1145 | base term. */ | |
9fc37b2b | 1146 | if (src_0 != 0 && known_base_value_p (src_0)) |
0134bf2d DE |
1147 | return src_0; |
1148 | ||
9fc37b2b | 1149 | if (src_1 != 0 && known_base_value_p (src_1)) |
0134bf2d DE |
1150 | return src_1; |
1151 | ||
d4b60170 | 1152 | /* Guess which operand is the base address: |
ec907dd8 JL |
1153 | If either operand is a symbol, then it is the base. If |
1154 | either operand is a CONST_INT, then the other is the base. */ | |
481683e1 | 1155 | if (CONST_INT_P (src_1) || CONSTANT_P (src_0)) |
2a2c8203 | 1156 | return find_base_value (src_0); |
481683e1 | 1157 | else if (CONST_INT_P (src_0) || CONSTANT_P (src_1)) |
ec907dd8 JL |
1158 | return find_base_value (src_1); |
1159 | ||
9ae8ffe7 | 1160 | return 0; |
2a2c8203 JC |
1161 | } |
1162 | ||
1163 | case LO_SUM: | |
1164 | /* The standard form is (lo_sum reg sym) so look only at the | |
1165 | second operand. */ | |
1166 | return find_base_value (XEXP (src, 1)); | |
9ae8ffe7 JL |
1167 | |
1168 | case AND: | |
1169 | /* If the second operand is constant set the base | |
ec5c56db | 1170 | address to the first operand. */ |
481683e1 | 1171 | if (CONST_INT_P (XEXP (src, 1)) && INTVAL (XEXP (src, 1)) != 0) |
2a2c8203 | 1172 | return find_base_value (XEXP (src, 0)); |
9ae8ffe7 JL |
1173 | return 0; |
1174 | ||
61f0131c | 1175 | case TRUNCATE: |
5932a4d4 | 1176 | /* As we do not know which address space the pointer is referring to, we can |
d4ebfa65 BE |
1177 | handle this only if the target does not support different pointer or |
1178 | address modes depending on the address space. */ | |
1179 | if (!target_default_pointer_address_modes_p ()) | |
1180 | break; | |
61f0131c R |
1181 | if (GET_MODE_SIZE (GET_MODE (src)) < GET_MODE_SIZE (Pmode)) |
1182 | break; | |
1183 | /* Fall through. */ | |
9ae8ffe7 | 1184 | case HIGH: |
d288e53d DE |
1185 | case PRE_INC: |
1186 | case PRE_DEC: | |
1187 | case POST_INC: | |
1188 | case POST_DEC: | |
1189 | case PRE_MODIFY: | |
1190 | case POST_MODIFY: | |
2a2c8203 | 1191 | return find_base_value (XEXP (src, 0)); |
1d300e19 | 1192 | |
0aacc8ed RK |
1193 | case ZERO_EXTEND: |
1194 | case SIGN_EXTEND: /* used for NT/Alpha pointers */ | |
5932a4d4 | 1195 | /* As we do not know which address space the pointer is referring to, we can |
d4ebfa65 BE |
1196 | handle this only if the target does not support different pointer or |
1197 | address modes depending on the address space. */ | |
1198 | if (!target_default_pointer_address_modes_p ()) | |
1199 | break; | |
1200 | ||
0aacc8ed RK |
1201 | { |
1202 | rtx temp = find_base_value (XEXP (src, 0)); | |
1203 | ||
5ae6cd0d | 1204 | if (temp != 0 && CONSTANT_P (temp)) |
0aacc8ed | 1205 | temp = convert_memory_address (Pmode, temp); |
0aacc8ed RK |
1206 | |
1207 | return temp; | |
1208 | } | |
1209 | ||
1d300e19 KG |
1210 | default: |
1211 | break; | |
9ae8ffe7 JL |
1212 | } |
1213 | ||
1214 | return 0; | |
1215 | } | |
1216 | ||
9fc37b2b RS |
1217 | /* Called from init_alias_analysis indirectly through note_stores, |
1218 | or directly if DEST is a register with a REG_NOALIAS note attached. | |
1219 | SET is null in the latter case. */ | |
9ae8ffe7 | 1220 | |
d4b60170 | 1221 | /* While scanning insns to find base values, reg_seen[N] is nonzero if |
9ae8ffe7 | 1222 | register N has been set in this function. */ |
d630245f | 1223 | static sbitmap reg_seen; |
9ae8ffe7 | 1224 | |
2a2c8203 | 1225 | static void |
7bc980e1 | 1226 | record_set (rtx dest, const_rtx set, void *data ATTRIBUTE_UNUSED) |
9ae8ffe7 | 1227 | { |
b3694847 | 1228 | unsigned regno; |
9ae8ffe7 | 1229 | rtx src; |
c28b4e40 | 1230 | int n; |
9ae8ffe7 | 1231 | |
f8cfc6aa | 1232 | if (!REG_P (dest)) |
9ae8ffe7 JL |
1233 | return; |
1234 | ||
fb6754f0 | 1235 | regno = REGNO (dest); |
9ae8ffe7 | 1236 | |
7a40b8b1 | 1237 | gcc_checking_assert (regno < VEC_length (rtx, reg_base_value)); |
ac606739 | 1238 | |
c28b4e40 JW |
1239 | /* If this spans multiple hard registers, then we must indicate that every |
1240 | register has an unusable value. */ | |
1241 | if (regno < FIRST_PSEUDO_REGISTER) | |
66fd46b6 | 1242 | n = hard_regno_nregs[regno][GET_MODE (dest)]; |
c28b4e40 JW |
1243 | else |
1244 | n = 1; | |
1245 | if (n != 1) | |
1246 | { | |
1247 | while (--n >= 0) | |
1248 | { | |
d630245f | 1249 | SET_BIT (reg_seen, regno + n); |
c28b4e40 JW |
1250 | new_reg_base_value[regno + n] = 0; |
1251 | } | |
1252 | return; | |
1253 | } | |
1254 | ||
9ae8ffe7 JL |
1255 | if (set) |
1256 | { | |
1257 | /* A CLOBBER wipes out any old value but does not prevent a previously | |
1258 | unset register from acquiring a base address (i.e. reg_seen is not | |
1259 | set). */ | |
1260 | if (GET_CODE (set) == CLOBBER) | |
1261 | { | |
ec907dd8 | 1262 | new_reg_base_value[regno] = 0; |
9ae8ffe7 JL |
1263 | return; |
1264 | } | |
1265 | src = SET_SRC (set); | |
1266 | } | |
1267 | else | |
1268 | { | |
9fc37b2b | 1269 | /* There's a REG_NOALIAS note against DEST. */ |
d630245f | 1270 | if (TEST_BIT (reg_seen, regno)) |
9ae8ffe7 | 1271 | { |
ec907dd8 | 1272 | new_reg_base_value[regno] = 0; |
9ae8ffe7 JL |
1273 | return; |
1274 | } | |
d630245f | 1275 | SET_BIT (reg_seen, regno); |
9fc37b2b | 1276 | new_reg_base_value[regno] = unique_base_value (unique_id++); |
9ae8ffe7 JL |
1277 | return; |
1278 | } | |
1279 | ||
5da6f168 RS |
1280 | /* If this is not the first set of REGNO, see whether the new value |
1281 | is related to the old one. There are two cases of interest: | |
1282 | ||
1283 | (1) The register might be assigned an entirely new value | |
1284 | that has the same base term as the original set. | |
1285 | ||
1286 | (2) The set might be a simple self-modification that | |
1287 | cannot change REGNO's base value. | |
1288 | ||
1289 | If neither case holds, reject the original base value as invalid. | |
1290 | Note that the following situation is not detected: | |
1291 | ||
c22cacf3 | 1292 | extern int x, y; int *p = &x; p += (&y-&x); |
5da6f168 | 1293 | |
9ae8ffe7 JL |
1294 | ANSI C does not allow computing the difference of addresses |
1295 | of distinct top level objects. */ | |
5da6f168 RS |
1296 | if (new_reg_base_value[regno] != 0 |
1297 | && find_base_value (src) != new_reg_base_value[regno]) | |
9ae8ffe7 JL |
1298 | switch (GET_CODE (src)) |
1299 | { | |
2a2c8203 | 1300 | case LO_SUM: |
9ae8ffe7 JL |
1301 | case MINUS: |
1302 | if (XEXP (src, 0) != dest && XEXP (src, 1) != dest) | |
ec907dd8 | 1303 | new_reg_base_value[regno] = 0; |
9ae8ffe7 | 1304 | break; |
61f0131c R |
1305 | case PLUS: |
1306 | /* If the value we add in the PLUS is also a valid base value, | |
1307 | this might be the actual base value, and the original value | |
1308 | an index. */ | |
1309 | { | |
1310 | rtx other = NULL_RTX; | |
1311 | ||
1312 | if (XEXP (src, 0) == dest) | |
1313 | other = XEXP (src, 1); | |
1314 | else if (XEXP (src, 1) == dest) | |
1315 | other = XEXP (src, 0); | |
1316 | ||
1317 | if (! other || find_base_value (other)) | |
1318 | new_reg_base_value[regno] = 0; | |
1319 | break; | |
1320 | } | |
9ae8ffe7 | 1321 | case AND: |
481683e1 | 1322 | if (XEXP (src, 0) != dest || !CONST_INT_P (XEXP (src, 1))) |
ec907dd8 | 1323 | new_reg_base_value[regno] = 0; |
9ae8ffe7 | 1324 | break; |
9ae8ffe7 | 1325 | default: |
ec907dd8 | 1326 | new_reg_base_value[regno] = 0; |
9ae8ffe7 JL |
1327 | break; |
1328 | } | |
1329 | /* If this is the first set of a register, record the value. */ | |
1330 | else if ((regno >= FIRST_PSEUDO_REGISTER || ! fixed_regs[regno]) | |
d630245f | 1331 | && ! TEST_BIT (reg_seen, regno) && new_reg_base_value[regno] == 0) |
ec907dd8 | 1332 | new_reg_base_value[regno] = find_base_value (src); |
9ae8ffe7 | 1333 | |
d630245f | 1334 | SET_BIT (reg_seen, regno); |
9ae8ffe7 JL |
1335 | } |
1336 | ||
8fd0a474 AM |
1337 | /* Return REG_BASE_VALUE for REGNO. Selective scheduler uses this to avoid |
1338 | using hard registers with non-null REG_BASE_VALUE for renaming. */ | |
1339 | rtx | |
1340 | get_reg_base_value (unsigned int regno) | |
1341 | { | |
1342 | return VEC_index (rtx, reg_base_value, regno); | |
1343 | } | |
1344 | ||
bb1acb3e RH |
1345 | /* If a value is known for REGNO, return it. */ |
1346 | ||
c22cacf3 | 1347 | rtx |
bb1acb3e RH |
1348 | get_reg_known_value (unsigned int regno) |
1349 | { | |
1350 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1351 | { | |
1352 | regno -= FIRST_PSEUDO_REGISTER; | |
9ff3c7ca SB |
1353 | if (regno < VEC_length (rtx, reg_known_value)) |
1354 | return VEC_index (rtx, reg_known_value, regno); | |
bb1acb3e RH |
1355 | } |
1356 | return NULL; | |
43fe47ca JW |
1357 | } |
1358 | ||
bb1acb3e RH |
1359 | /* Set it. */ |
1360 | ||
1361 | static void | |
1362 | set_reg_known_value (unsigned int regno, rtx val) | |
1363 | { | |
1364 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1365 | { | |
1366 | regno -= FIRST_PSEUDO_REGISTER; | |
9ff3c7ca SB |
1367 | if (regno < VEC_length (rtx, reg_known_value)) |
1368 | VEC_replace (rtx, reg_known_value, regno, val); | |
bb1acb3e RH |
1369 | } |
1370 | } | |
1371 | ||
1372 | /* Similarly for reg_known_equiv_p. */ | |
1373 | ||
1374 | bool | |
1375 | get_reg_known_equiv_p (unsigned int regno) | |
1376 | { | |
1377 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1378 | { | |
1379 | regno -= FIRST_PSEUDO_REGISTER; | |
9ff3c7ca SB |
1380 | if (regno < VEC_length (rtx, reg_known_value)) |
1381 | return TEST_BIT (reg_known_equiv_p, regno); | |
bb1acb3e RH |
1382 | } |
1383 | return false; | |
1384 | } | |
1385 | ||
1386 | static void | |
1387 | set_reg_known_equiv_p (unsigned int regno, bool val) | |
1388 | { | |
1389 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1390 | { | |
1391 | regno -= FIRST_PSEUDO_REGISTER; | |
9ff3c7ca SB |
1392 | if (regno < VEC_length (rtx, reg_known_value)) |
1393 | { | |
1394 | if (val) | |
1395 | SET_BIT (reg_known_equiv_p, regno); | |
1396 | else | |
1397 | RESET_BIT (reg_known_equiv_p, regno); | |
1398 | } | |
bb1acb3e RH |
1399 | } |
1400 | } | |
1401 | ||
1402 | ||
db048faf MM |
1403 | /* Returns a canonical version of X, from the point of view alias |
1404 | analysis. (For example, if X is a MEM whose address is a register, | |
1405 | and the register has a known value (say a SYMBOL_REF), then a MEM | |
1406 | whose address is the SYMBOL_REF is returned.) */ | |
1407 | ||
1408 | rtx | |
4682ae04 | 1409 | canon_rtx (rtx x) |
9ae8ffe7 JL |
1410 | { |
1411 | /* Recursively look for equivalences. */ | |
f8cfc6aa | 1412 | if (REG_P (x) && REGNO (x) >= FIRST_PSEUDO_REGISTER) |
bb1acb3e RH |
1413 | { |
1414 | rtx t = get_reg_known_value (REGNO (x)); | |
1415 | if (t == x) | |
1416 | return x; | |
1417 | if (t) | |
1418 | return canon_rtx (t); | |
1419 | } | |
1420 | ||
1421 | if (GET_CODE (x) == PLUS) | |
9ae8ffe7 JL |
1422 | { |
1423 | rtx x0 = canon_rtx (XEXP (x, 0)); | |
1424 | rtx x1 = canon_rtx (XEXP (x, 1)); | |
1425 | ||
1426 | if (x0 != XEXP (x, 0) || x1 != XEXP (x, 1)) | |
1427 | { | |
481683e1 | 1428 | if (CONST_INT_P (x0)) |
0a81f074 | 1429 | return plus_constant (GET_MODE (x), x1, INTVAL (x0)); |
481683e1 | 1430 | else if (CONST_INT_P (x1)) |
0a81f074 | 1431 | return plus_constant (GET_MODE (x), x0, INTVAL (x1)); |
38a448ca | 1432 | return gen_rtx_PLUS (GET_MODE (x), x0, x1); |
9ae8ffe7 JL |
1433 | } |
1434 | } | |
d4b60170 | 1435 | |
9ae8ffe7 JL |
1436 | /* This gives us much better alias analysis when called from |
1437 | the loop optimizer. Note we want to leave the original | |
1438 | MEM alone, but need to return the canonicalized MEM with | |
1439 | all the flags with their original values. */ | |
3c0cb5de | 1440 | else if (MEM_P (x)) |
f1ec5147 | 1441 | x = replace_equiv_address_nv (x, canon_rtx (XEXP (x, 0))); |
d4b60170 | 1442 | |
9ae8ffe7 JL |
1443 | return x; |
1444 | } | |
1445 | ||
1446 | /* Return 1 if X and Y are identical-looking rtx's. | |
45183e03 | 1447 | Expect that X and Y has been already canonicalized. |
9ae8ffe7 JL |
1448 | |
1449 | We use the data in reg_known_value above to see if two registers with | |
1450 | different numbers are, in fact, equivalent. */ | |
1451 | ||
1452 | static int | |
ed7a4b4b | 1453 | rtx_equal_for_memref_p (const_rtx x, const_rtx y) |
9ae8ffe7 | 1454 | { |
b3694847 SS |
1455 | int i; |
1456 | int j; | |
1457 | enum rtx_code code; | |
1458 | const char *fmt; | |
9ae8ffe7 JL |
1459 | |
1460 | if (x == 0 && y == 0) | |
1461 | return 1; | |
1462 | if (x == 0 || y == 0) | |
1463 | return 0; | |
d4b60170 | 1464 | |
9ae8ffe7 JL |
1465 | if (x == y) |
1466 | return 1; | |
1467 | ||
1468 | code = GET_CODE (x); | |
1469 | /* Rtx's of different codes cannot be equal. */ | |
1470 | if (code != GET_CODE (y)) | |
1471 | return 0; | |
1472 | ||
1473 | /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. | |
1474 | (REG:SI x) and (REG:HI x) are NOT equivalent. */ | |
1475 | ||
1476 | if (GET_MODE (x) != GET_MODE (y)) | |
1477 | return 0; | |
1478 | ||
db048faf MM |
1479 | /* Some RTL can be compared without a recursive examination. */ |
1480 | switch (code) | |
1481 | { | |
1482 | case REG: | |
1483 | return REGNO (x) == REGNO (y); | |
1484 | ||
1485 | case LABEL_REF: | |
1486 | return XEXP (x, 0) == XEXP (y, 0); | |
ca7fd9cd | 1487 | |
db048faf MM |
1488 | case SYMBOL_REF: |
1489 | return XSTR (x, 0) == XSTR (y, 0); | |
1490 | ||
40e02b4a | 1491 | case VALUE: |
d8116890 | 1492 | CASE_CONST_UNIQUE: |
db048faf MM |
1493 | /* There's no need to compare the contents of CONST_DOUBLEs or |
1494 | CONST_INTs because pointer equality is a good enough | |
1495 | comparison for these nodes. */ | |
1496 | return 0; | |
1497 | ||
db048faf MM |
1498 | default: |
1499 | break; | |
1500 | } | |
9ae8ffe7 | 1501 | |
45183e03 JH |
1502 | /* canon_rtx knows how to handle plus. No need to canonicalize. */ |
1503 | if (code == PLUS) | |
9ae8ffe7 JL |
1504 | return ((rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 0)) |
1505 | && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 1))) | |
1506 | || (rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 1)) | |
1507 | && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 0)))); | |
45183e03 JH |
1508 | /* For commutative operations, the RTX match if the operand match in any |
1509 | order. Also handle the simple binary and unary cases without a loop. */ | |
ec8e098d | 1510 | if (COMMUTATIVE_P (x)) |
45183e03 JH |
1511 | { |
1512 | rtx xop0 = canon_rtx (XEXP (x, 0)); | |
1513 | rtx yop0 = canon_rtx (XEXP (y, 0)); | |
1514 | rtx yop1 = canon_rtx (XEXP (y, 1)); | |
1515 | ||
1516 | return ((rtx_equal_for_memref_p (xop0, yop0) | |
1517 | && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), yop1)) | |
1518 | || (rtx_equal_for_memref_p (xop0, yop1) | |
1519 | && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), yop0))); | |
1520 | } | |
ec8e098d | 1521 | else if (NON_COMMUTATIVE_P (x)) |
45183e03 JH |
1522 | { |
1523 | return (rtx_equal_for_memref_p (canon_rtx (XEXP (x, 0)), | |
4682ae04 | 1524 | canon_rtx (XEXP (y, 0))) |
45183e03 JH |
1525 | && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), |
1526 | canon_rtx (XEXP (y, 1)))); | |
1527 | } | |
ec8e098d | 1528 | else if (UNARY_P (x)) |
45183e03 | 1529 | return rtx_equal_for_memref_p (canon_rtx (XEXP (x, 0)), |
4682ae04 | 1530 | canon_rtx (XEXP (y, 0))); |
9ae8ffe7 JL |
1531 | |
1532 | /* Compare the elements. If any pair of corresponding elements | |
de12be17 JC |
1533 | fail to match, return 0 for the whole things. |
1534 | ||
1535 | Limit cases to types which actually appear in addresses. */ | |
9ae8ffe7 JL |
1536 | |
1537 | fmt = GET_RTX_FORMAT (code); | |
1538 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
1539 | { | |
1540 | switch (fmt[i]) | |
1541 | { | |
9ae8ffe7 JL |
1542 | case 'i': |
1543 | if (XINT (x, i) != XINT (y, i)) | |
1544 | return 0; | |
1545 | break; | |
1546 | ||
9ae8ffe7 JL |
1547 | case 'E': |
1548 | /* Two vectors must have the same length. */ | |
1549 | if (XVECLEN (x, i) != XVECLEN (y, i)) | |
1550 | return 0; | |
1551 | ||
1552 | /* And the corresponding elements must match. */ | |
1553 | for (j = 0; j < XVECLEN (x, i); j++) | |
45183e03 JH |
1554 | if (rtx_equal_for_memref_p (canon_rtx (XVECEXP (x, i, j)), |
1555 | canon_rtx (XVECEXP (y, i, j))) == 0) | |
9ae8ffe7 JL |
1556 | return 0; |
1557 | break; | |
1558 | ||
1559 | case 'e': | |
45183e03 JH |
1560 | if (rtx_equal_for_memref_p (canon_rtx (XEXP (x, i)), |
1561 | canon_rtx (XEXP (y, i))) == 0) | |
9ae8ffe7 JL |
1562 | return 0; |
1563 | break; | |
1564 | ||
3237ac18 AH |
1565 | /* This can happen for asm operands. */ |
1566 | case 's': | |
1567 | if (strcmp (XSTR (x, i), XSTR (y, i))) | |
1568 | return 0; | |
1569 | break; | |
1570 | ||
aee21ba9 JL |
1571 | /* This can happen for an asm which clobbers memory. */ |
1572 | case '0': | |
1573 | break; | |
1574 | ||
9ae8ffe7 JL |
1575 | /* It is believed that rtx's at this level will never |
1576 | contain anything but integers and other rtx's, | |
1577 | except for within LABEL_REFs and SYMBOL_REFs. */ | |
1578 | default: | |
298e6adc | 1579 | gcc_unreachable (); |
9ae8ffe7 JL |
1580 | } |
1581 | } | |
1582 | return 1; | |
1583 | } | |
1584 | ||
9e412ca3 | 1585 | static rtx |
4682ae04 | 1586 | find_base_term (rtx x) |
9ae8ffe7 | 1587 | { |
eab5c70a | 1588 | cselib_val *val; |
6f2ffb4b AO |
1589 | struct elt_loc_list *l, *f; |
1590 | rtx ret; | |
eab5c70a | 1591 | |
b949ea8b JW |
1592 | #if defined (FIND_BASE_TERM) |
1593 | /* Try machine-dependent ways to find the base term. */ | |
1594 | x = FIND_BASE_TERM (x); | |
1595 | #endif | |
1596 | ||
9ae8ffe7 JL |
1597 | switch (GET_CODE (x)) |
1598 | { | |
1599 | case REG: | |
1600 | return REG_BASE_VALUE (x); | |
1601 | ||
d288e53d | 1602 | case TRUNCATE: |
5932a4d4 | 1603 | /* As we do not know which address space the pointer is referring to, we can |
d4ebfa65 BE |
1604 | handle this only if the target does not support different pointer or |
1605 | address modes depending on the address space. */ | |
1606 | if (!target_default_pointer_address_modes_p ()) | |
1607 | return 0; | |
d288e53d | 1608 | if (GET_MODE_SIZE (GET_MODE (x)) < GET_MODE_SIZE (Pmode)) |
ca7fd9cd | 1609 | return 0; |
d288e53d | 1610 | /* Fall through. */ |
9ae8ffe7 | 1611 | case HIGH: |
6d849a2a JL |
1612 | case PRE_INC: |
1613 | case PRE_DEC: | |
1614 | case POST_INC: | |
1615 | case POST_DEC: | |
d288e53d DE |
1616 | case PRE_MODIFY: |
1617 | case POST_MODIFY: | |
6d849a2a JL |
1618 | return find_base_term (XEXP (x, 0)); |
1619 | ||
1abade85 RK |
1620 | case ZERO_EXTEND: |
1621 | case SIGN_EXTEND: /* Used for Alpha/NT pointers */ | |
5932a4d4 | 1622 | /* As we do not know which address space the pointer is referring to, we can |
d4ebfa65 BE |
1623 | handle this only if the target does not support different pointer or |
1624 | address modes depending on the address space. */ | |
1625 | if (!target_default_pointer_address_modes_p ()) | |
1626 | return 0; | |
1627 | ||
1abade85 RK |
1628 | { |
1629 | rtx temp = find_base_term (XEXP (x, 0)); | |
1630 | ||
5ae6cd0d | 1631 | if (temp != 0 && CONSTANT_P (temp)) |
1abade85 | 1632 | temp = convert_memory_address (Pmode, temp); |
1abade85 RK |
1633 | |
1634 | return temp; | |
1635 | } | |
1636 | ||
eab5c70a BS |
1637 | case VALUE: |
1638 | val = CSELIB_VAL_PTR (x); | |
6f2ffb4b AO |
1639 | ret = NULL_RTX; |
1640 | ||
40e02b4a | 1641 | if (!val) |
6f2ffb4b AO |
1642 | return ret; |
1643 | ||
1644 | f = val->locs; | |
1645 | /* Temporarily reset val->locs to avoid infinite recursion. */ | |
1646 | val->locs = NULL; | |
1647 | ||
1648 | for (l = f; l; l = l->next) | |
1649 | if (GET_CODE (l->loc) == VALUE | |
1650 | && CSELIB_VAL_PTR (l->loc)->locs | |
1651 | && !CSELIB_VAL_PTR (l->loc)->locs->next | |
1652 | && CSELIB_VAL_PTR (l->loc)->locs->loc == x) | |
1653 | continue; | |
1654 | else if ((ret = find_base_term (l->loc)) != 0) | |
1655 | break; | |
1656 | ||
1657 | val->locs = f; | |
1658 | return ret; | |
eab5c70a | 1659 | |
023f059b JJ |
1660 | case LO_SUM: |
1661 | /* The standard form is (lo_sum reg sym) so look only at the | |
1662 | second operand. */ | |
1663 | return find_base_term (XEXP (x, 1)); | |
1664 | ||
9ae8ffe7 JL |
1665 | case CONST: |
1666 | x = XEXP (x, 0); | |
1667 | if (GET_CODE (x) != PLUS && GET_CODE (x) != MINUS) | |
1668 | return 0; | |
938d968e | 1669 | /* Fall through. */ |
9ae8ffe7 JL |
1670 | case PLUS: |
1671 | case MINUS: | |
1672 | { | |
3c567fae JL |
1673 | rtx tmp1 = XEXP (x, 0); |
1674 | rtx tmp2 = XEXP (x, 1); | |
1675 | ||
f5143c46 | 1676 | /* This is a little bit tricky since we have to determine which of |
3c567fae JL |
1677 | the two operands represents the real base address. Otherwise this |
1678 | routine may return the index register instead of the base register. | |
1679 | ||
1680 | That may cause us to believe no aliasing was possible, when in | |
1681 | fact aliasing is possible. | |
1682 | ||
1683 | We use a few simple tests to guess the base register. Additional | |
1684 | tests can certainly be added. For example, if one of the operands | |
1685 | is a shift or multiply, then it must be the index register and the | |
1686 | other operand is the base register. */ | |
ca7fd9cd | 1687 | |
b949ea8b JW |
1688 | if (tmp1 == pic_offset_table_rtx && CONSTANT_P (tmp2)) |
1689 | return find_base_term (tmp2); | |
1690 | ||
3c567fae JL |
1691 | /* If either operand is known to be a pointer, then use it |
1692 | to determine the base term. */ | |
3502dc9c | 1693 | if (REG_P (tmp1) && REG_POINTER (tmp1)) |
7eba2d1f LM |
1694 | { |
1695 | rtx base = find_base_term (tmp1); | |
1696 | if (base) | |
1697 | return base; | |
1698 | } | |
3c567fae | 1699 | |
3502dc9c | 1700 | if (REG_P (tmp2) && REG_POINTER (tmp2)) |
7eba2d1f LM |
1701 | { |
1702 | rtx base = find_base_term (tmp2); | |
1703 | if (base) | |
1704 | return base; | |
1705 | } | |
3c567fae JL |
1706 | |
1707 | /* Neither operand was known to be a pointer. Go ahead and find the | |
1708 | base term for both operands. */ | |
1709 | tmp1 = find_base_term (tmp1); | |
1710 | tmp2 = find_base_term (tmp2); | |
1711 | ||
1712 | /* If either base term is named object or a special address | |
1713 | (like an argument or stack reference), then use it for the | |
1714 | base term. */ | |
9fc37b2b | 1715 | if (tmp1 != 0 && known_base_value_p (tmp1)) |
3c567fae JL |
1716 | return tmp1; |
1717 | ||
9fc37b2b | 1718 | if (tmp2 != 0 && known_base_value_p (tmp2)) |
3c567fae JL |
1719 | return tmp2; |
1720 | ||
1721 | /* We could not determine which of the two operands was the | |
1722 | base register and which was the index. So we can determine | |
1723 | nothing from the base alias check. */ | |
1724 | return 0; | |
9ae8ffe7 JL |
1725 | } |
1726 | ||
1727 | case AND: | |
481683e1 | 1728 | if (CONST_INT_P (XEXP (x, 1)) && INTVAL (XEXP (x, 1)) != 0) |
d288e53d | 1729 | return find_base_term (XEXP (x, 0)); |
9ae8ffe7 JL |
1730 | return 0; |
1731 | ||
1732 | case SYMBOL_REF: | |
1733 | case LABEL_REF: | |
1734 | return x; | |
1735 | ||
1736 | default: | |
1737 | return 0; | |
1738 | } | |
1739 | } | |
1740 | ||
9e412ca3 RS |
1741 | /* Return true if accesses to address X may alias accesses based |
1742 | on the stack pointer. */ | |
1743 | ||
1744 | bool | |
1745 | may_be_sp_based_p (rtx x) | |
1746 | { | |
1747 | rtx base = find_base_term (x); | |
1748 | return !base || base == static_reg_base_value[STACK_POINTER_REGNUM]; | |
1749 | } | |
1750 | ||
9ae8ffe7 JL |
1751 | /* Return 0 if the addresses X and Y are known to point to different |
1752 | objects, 1 if they might be pointers to the same object. */ | |
1753 | ||
1754 | static int | |
4682ae04 AJ |
1755 | base_alias_check (rtx x, rtx y, enum machine_mode x_mode, |
1756 | enum machine_mode y_mode) | |
9ae8ffe7 JL |
1757 | { |
1758 | rtx x_base = find_base_term (x); | |
1759 | rtx y_base = find_base_term (y); | |
1760 | ||
1c72c7f6 JC |
1761 | /* If the address itself has no known base see if a known equivalent |
1762 | value has one. If either address still has no known base, nothing | |
1763 | is known about aliasing. */ | |
1764 | if (x_base == 0) | |
1765 | { | |
1766 | rtx x_c; | |
d4b60170 | 1767 | |
1c72c7f6 JC |
1768 | if (! flag_expensive_optimizations || (x_c = canon_rtx (x)) == x) |
1769 | return 1; | |
d4b60170 | 1770 | |
1c72c7f6 JC |
1771 | x_base = find_base_term (x_c); |
1772 | if (x_base == 0) | |
1773 | return 1; | |
1774 | } | |
9ae8ffe7 | 1775 | |
1c72c7f6 JC |
1776 | if (y_base == 0) |
1777 | { | |
1778 | rtx y_c; | |
1779 | if (! flag_expensive_optimizations || (y_c = canon_rtx (y)) == y) | |
1780 | return 1; | |
d4b60170 | 1781 | |
1c72c7f6 JC |
1782 | y_base = find_base_term (y_c); |
1783 | if (y_base == 0) | |
1784 | return 1; | |
1785 | } | |
1786 | ||
1787 | /* If the base addresses are equal nothing is known about aliasing. */ | |
1788 | if (rtx_equal_p (x_base, y_base)) | |
9ae8ffe7 JL |
1789 | return 1; |
1790 | ||
435da628 UB |
1791 | /* The base addresses are different expressions. If they are not accessed |
1792 | via AND, there is no conflict. We can bring knowledge of object | |
1793 | alignment into play here. For example, on alpha, "char a, b;" can | |
1794 | alias one another, though "char a; long b;" cannot. AND addesses may | |
1795 | implicitly alias surrounding objects; i.e. unaligned access in DImode | |
1796 | via AND address can alias all surrounding object types except those | |
1797 | with aligment 8 or higher. */ | |
1798 | if (GET_CODE (x) == AND && GET_CODE (y) == AND) | |
1799 | return 1; | |
1800 | if (GET_CODE (x) == AND | |
481683e1 | 1801 | && (!CONST_INT_P (XEXP (x, 1)) |
435da628 UB |
1802 | || (int) GET_MODE_UNIT_SIZE (y_mode) < -INTVAL (XEXP (x, 1)))) |
1803 | return 1; | |
1804 | if (GET_CODE (y) == AND | |
481683e1 | 1805 | && (!CONST_INT_P (XEXP (y, 1)) |
435da628 UB |
1806 | || (int) GET_MODE_UNIT_SIZE (x_mode) < -INTVAL (XEXP (y, 1)))) |
1807 | return 1; | |
1808 | ||
1809 | /* Differing symbols not accessed via AND never alias. */ | |
9ae8ffe7 | 1810 | if (GET_CODE (x_base) != ADDRESS && GET_CODE (y_base) != ADDRESS) |
435da628 | 1811 | return 0; |
9ae8ffe7 | 1812 | |
9fc37b2b | 1813 | if (unique_base_value_p (x_base) || unique_base_value_p (y_base)) |
9ae8ffe7 JL |
1814 | return 0; |
1815 | ||
0d3c82d6 | 1816 | return 1; |
9ae8ffe7 JL |
1817 | } |
1818 | ||
a5628378 AO |
1819 | /* Callback for for_each_rtx, that returns 1 upon encountering a VALUE |
1820 | whose UID is greater than the int uid that D points to. */ | |
1821 | ||
1822 | static int | |
1823 | refs_newer_value_cb (rtx *x, void *d) | |
1824 | { | |
1825 | if (GET_CODE (*x) == VALUE && CSELIB_VAL_PTR (*x)->uid > *(int *)d) | |
1826 | return 1; | |
1827 | ||
1828 | return 0; | |
1829 | } | |
1830 | ||
1831 | /* Return TRUE if EXPR refers to a VALUE whose uid is greater than | |
1832 | that of V. */ | |
1833 | ||
1834 | static bool | |
1835 | refs_newer_value_p (rtx expr, rtx v) | |
1836 | { | |
1837 | int minuid = CSELIB_VAL_PTR (v)->uid; | |
1838 | ||
1839 | return for_each_rtx (&expr, refs_newer_value_cb, &minuid); | |
1840 | } | |
1841 | ||
eab5c70a BS |
1842 | /* Convert the address X into something we can use. This is done by returning |
1843 | it unchanged unless it is a value; in the latter case we call cselib to get | |
1844 | a more useful rtx. */ | |
3bdf5ad1 | 1845 | |
a13d4ebf | 1846 | rtx |
4682ae04 | 1847 | get_addr (rtx x) |
eab5c70a BS |
1848 | { |
1849 | cselib_val *v; | |
1850 | struct elt_loc_list *l; | |
1851 | ||
1852 | if (GET_CODE (x) != VALUE) | |
1853 | return x; | |
1854 | v = CSELIB_VAL_PTR (x); | |
40e02b4a JH |
1855 | if (v) |
1856 | { | |
0f68ba3e AO |
1857 | bool have_equivs = cselib_have_permanent_equivalences (); |
1858 | if (have_equivs) | |
1859 | v = canonical_cselib_val (v); | |
40e02b4a JH |
1860 | for (l = v->locs; l; l = l->next) |
1861 | if (CONSTANT_P (l->loc)) | |
1862 | return l->loc; | |
1863 | for (l = v->locs; l; l = l->next) | |
0f68ba3e AO |
1864 | if (!REG_P (l->loc) && !MEM_P (l->loc) |
1865 | /* Avoid infinite recursion when potentially dealing with | |
1866 | var-tracking artificial equivalences, by skipping the | |
1867 | equivalences themselves, and not choosing expressions | |
1868 | that refer to newer VALUEs. */ | |
1869 | && (!have_equivs | |
1870 | || (GET_CODE (l->loc) != VALUE | |
1871 | && !refs_newer_value_p (l->loc, x)))) | |
a5628378 | 1872 | return l->loc; |
0f68ba3e AO |
1873 | if (have_equivs) |
1874 | { | |
1875 | for (l = v->locs; l; l = l->next) | |
1876 | if (REG_P (l->loc) | |
1877 | || (GET_CODE (l->loc) != VALUE | |
1878 | && !refs_newer_value_p (l->loc, x))) | |
1879 | return l->loc; | |
1880 | /* Return the canonical value. */ | |
1881 | return v->val_rtx; | |
1882 | } | |
1883 | if (v->locs) | |
1884 | return v->locs->loc; | |
40e02b4a | 1885 | } |
eab5c70a BS |
1886 | return x; |
1887 | } | |
1888 | ||
39cec1ac MH |
1889 | /* Return the address of the (N_REFS + 1)th memory reference to ADDR |
1890 | where SIZE is the size in bytes of the memory reference. If ADDR | |
1891 | is not modified by the memory reference then ADDR is returned. */ | |
1892 | ||
04e2b4d3 | 1893 | static rtx |
4682ae04 | 1894 | addr_side_effect_eval (rtx addr, int size, int n_refs) |
39cec1ac MH |
1895 | { |
1896 | int offset = 0; | |
ca7fd9cd | 1897 | |
39cec1ac MH |
1898 | switch (GET_CODE (addr)) |
1899 | { | |
1900 | case PRE_INC: | |
1901 | offset = (n_refs + 1) * size; | |
1902 | break; | |
1903 | case PRE_DEC: | |
1904 | offset = -(n_refs + 1) * size; | |
1905 | break; | |
1906 | case POST_INC: | |
1907 | offset = n_refs * size; | |
1908 | break; | |
1909 | case POST_DEC: | |
1910 | offset = -n_refs * size; | |
1911 | break; | |
1912 | ||
1913 | default: | |
1914 | return addr; | |
1915 | } | |
ca7fd9cd | 1916 | |
39cec1ac | 1917 | if (offset) |
45183e03 | 1918 | addr = gen_rtx_PLUS (GET_MODE (addr), XEXP (addr, 0), |
c22cacf3 | 1919 | GEN_INT (offset)); |
39cec1ac MH |
1920 | else |
1921 | addr = XEXP (addr, 0); | |
45183e03 | 1922 | addr = canon_rtx (addr); |
39cec1ac MH |
1923 | |
1924 | return addr; | |
1925 | } | |
1926 | ||
f47e08d9 RG |
1927 | /* Return one if X and Y (memory addresses) reference the |
1928 | same location in memory or if the references overlap. | |
1929 | Return zero if they do not overlap, else return | |
1930 | minus one in which case they still might reference the same location. | |
1931 | ||
1932 | C is an offset accumulator. When | |
9ae8ffe7 JL |
1933 | C is nonzero, we are testing aliases between X and Y + C. |
1934 | XSIZE is the size in bytes of the X reference, | |
1935 | similarly YSIZE is the size in bytes for Y. | |
45183e03 | 1936 | Expect that canon_rtx has been already called for X and Y. |
9ae8ffe7 JL |
1937 | |
1938 | If XSIZE or YSIZE is zero, we do not know the amount of memory being | |
1939 | referenced (the reference was BLKmode), so make the most pessimistic | |
1940 | assumptions. | |
1941 | ||
c02f035f RH |
1942 | If XSIZE or YSIZE is negative, we may access memory outside the object |
1943 | being referenced as a side effect. This can happen when using AND to | |
1944 | align memory references, as is done on the Alpha. | |
1945 | ||
9ae8ffe7 | 1946 | Nice to notice that varying addresses cannot conflict with fp if no |
f47e08d9 RG |
1947 | local variables had their addresses taken, but that's too hard now. |
1948 | ||
1949 | ??? Contrary to the tree alias oracle this does not return | |
1950 | one for X + non-constant and Y + non-constant when X and Y are equal. | |
1951 | If that is fixed the TBAA hack for union type-punning can be removed. */ | |
9ae8ffe7 | 1952 | |
9ae8ffe7 | 1953 | static int |
4682ae04 | 1954 | memrefs_conflict_p (int xsize, rtx x, int ysize, rtx y, HOST_WIDE_INT c) |
9ae8ffe7 | 1955 | { |
eab5c70a | 1956 | if (GET_CODE (x) == VALUE) |
5312b066 JJ |
1957 | { |
1958 | if (REG_P (y)) | |
1959 | { | |
24f8d71e JJ |
1960 | struct elt_loc_list *l = NULL; |
1961 | if (CSELIB_VAL_PTR (x)) | |
a5628378 AO |
1962 | for (l = canonical_cselib_val (CSELIB_VAL_PTR (x))->locs; |
1963 | l; l = l->next) | |
24f8d71e JJ |
1964 | if (REG_P (l->loc) && rtx_equal_for_memref_p (l->loc, y)) |
1965 | break; | |
5312b066 JJ |
1966 | if (l) |
1967 | x = y; | |
1968 | else | |
1969 | x = get_addr (x); | |
1970 | } | |
1971 | /* Don't call get_addr if y is the same VALUE. */ | |
1972 | else if (x != y) | |
1973 | x = get_addr (x); | |
1974 | } | |
eab5c70a | 1975 | if (GET_CODE (y) == VALUE) |
5312b066 JJ |
1976 | { |
1977 | if (REG_P (x)) | |
1978 | { | |
24f8d71e JJ |
1979 | struct elt_loc_list *l = NULL; |
1980 | if (CSELIB_VAL_PTR (y)) | |
a5628378 AO |
1981 | for (l = canonical_cselib_val (CSELIB_VAL_PTR (y))->locs; |
1982 | l; l = l->next) | |
24f8d71e JJ |
1983 | if (REG_P (l->loc) && rtx_equal_for_memref_p (l->loc, x)) |
1984 | break; | |
5312b066 JJ |
1985 | if (l) |
1986 | y = x; | |
1987 | else | |
1988 | y = get_addr (y); | |
1989 | } | |
1990 | /* Don't call get_addr if x is the same VALUE. */ | |
1991 | else if (y != x) | |
1992 | y = get_addr (y); | |
1993 | } | |
9ae8ffe7 JL |
1994 | if (GET_CODE (x) == HIGH) |
1995 | x = XEXP (x, 0); | |
1996 | else if (GET_CODE (x) == LO_SUM) | |
1997 | x = XEXP (x, 1); | |
1998 | else | |
45183e03 | 1999 | x = addr_side_effect_eval (x, xsize, 0); |
9ae8ffe7 JL |
2000 | if (GET_CODE (y) == HIGH) |
2001 | y = XEXP (y, 0); | |
2002 | else if (GET_CODE (y) == LO_SUM) | |
2003 | y = XEXP (y, 1); | |
2004 | else | |
45183e03 | 2005 | y = addr_side_effect_eval (y, ysize, 0); |
9ae8ffe7 JL |
2006 | |
2007 | if (rtx_equal_for_memref_p (x, y)) | |
2008 | { | |
c02f035f | 2009 | if (xsize <= 0 || ysize <= 0) |
9ae8ffe7 JL |
2010 | return 1; |
2011 | if (c >= 0 && xsize > c) | |
2012 | return 1; | |
2013 | if (c < 0 && ysize+c > 0) | |
2014 | return 1; | |
2015 | return 0; | |
2016 | } | |
2017 | ||
6e73e666 JC |
2018 | /* This code used to check for conflicts involving stack references and |
2019 | globals but the base address alias code now handles these cases. */ | |
9ae8ffe7 JL |
2020 | |
2021 | if (GET_CODE (x) == PLUS) | |
2022 | { | |
2023 | /* The fact that X is canonicalized means that this | |
2024 | PLUS rtx is canonicalized. */ | |
2025 | rtx x0 = XEXP (x, 0); | |
2026 | rtx x1 = XEXP (x, 1); | |
2027 | ||
2028 | if (GET_CODE (y) == PLUS) | |
2029 | { | |
2030 | /* The fact that Y is canonicalized means that this | |
2031 | PLUS rtx is canonicalized. */ | |
2032 | rtx y0 = XEXP (y, 0); | |
2033 | rtx y1 = XEXP (y, 1); | |
2034 | ||
2035 | if (rtx_equal_for_memref_p (x1, y1)) | |
2036 | return memrefs_conflict_p (xsize, x0, ysize, y0, c); | |
2037 | if (rtx_equal_for_memref_p (x0, y0)) | |
2038 | return memrefs_conflict_p (xsize, x1, ysize, y1, c); | |
481683e1 | 2039 | if (CONST_INT_P (x1)) |
63be02db | 2040 | { |
481683e1 | 2041 | if (CONST_INT_P (y1)) |
63be02db JM |
2042 | return memrefs_conflict_p (xsize, x0, ysize, y0, |
2043 | c - INTVAL (x1) + INTVAL (y1)); | |
2044 | else | |
2045 | return memrefs_conflict_p (xsize, x0, ysize, y, | |
2046 | c - INTVAL (x1)); | |
2047 | } | |
481683e1 | 2048 | else if (CONST_INT_P (y1)) |
9ae8ffe7 JL |
2049 | return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1)); |
2050 | ||
f47e08d9 | 2051 | return -1; |
9ae8ffe7 | 2052 | } |
481683e1 | 2053 | else if (CONST_INT_P (x1)) |
9ae8ffe7 JL |
2054 | return memrefs_conflict_p (xsize, x0, ysize, y, c - INTVAL (x1)); |
2055 | } | |
2056 | else if (GET_CODE (y) == PLUS) | |
2057 | { | |
2058 | /* The fact that Y is canonicalized means that this | |
2059 | PLUS rtx is canonicalized. */ | |
2060 | rtx y0 = XEXP (y, 0); | |
2061 | rtx y1 = XEXP (y, 1); | |
2062 | ||
481683e1 | 2063 | if (CONST_INT_P (y1)) |
9ae8ffe7 JL |
2064 | return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1)); |
2065 | else | |
f47e08d9 | 2066 | return -1; |
9ae8ffe7 JL |
2067 | } |
2068 | ||
2069 | if (GET_CODE (x) == GET_CODE (y)) | |
2070 | switch (GET_CODE (x)) | |
2071 | { | |
2072 | case MULT: | |
2073 | { | |
2074 | /* Handle cases where we expect the second operands to be the | |
2075 | same, and check only whether the first operand would conflict | |
2076 | or not. */ | |
2077 | rtx x0, y0; | |
2078 | rtx x1 = canon_rtx (XEXP (x, 1)); | |
2079 | rtx y1 = canon_rtx (XEXP (y, 1)); | |
2080 | if (! rtx_equal_for_memref_p (x1, y1)) | |
f47e08d9 | 2081 | return -1; |
9ae8ffe7 JL |
2082 | x0 = canon_rtx (XEXP (x, 0)); |
2083 | y0 = canon_rtx (XEXP (y, 0)); | |
2084 | if (rtx_equal_for_memref_p (x0, y0)) | |
2085 | return (xsize == 0 || ysize == 0 | |
2086 | || (c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)); | |
2087 | ||
2088 | /* Can't properly adjust our sizes. */ | |
481683e1 | 2089 | if (!CONST_INT_P (x1)) |
f47e08d9 | 2090 | return -1; |
9ae8ffe7 JL |
2091 | xsize /= INTVAL (x1); |
2092 | ysize /= INTVAL (x1); | |
2093 | c /= INTVAL (x1); | |
2094 | return memrefs_conflict_p (xsize, x0, ysize, y0, c); | |
2095 | } | |
1d300e19 KG |
2096 | |
2097 | default: | |
2098 | break; | |
9ae8ffe7 JL |
2099 | } |
2100 | ||
a9bf4fe2 AO |
2101 | /* Deal with alignment ANDs by adjusting offset and size so as to |
2102 | cover the maximum range, without taking any previously known | |
2103 | alignment into account. */ | |
481683e1 | 2104 | if (GET_CODE (x) == AND && CONST_INT_P (XEXP (x, 1))) |
56ee9281 | 2105 | { |
a9bf4fe2 AO |
2106 | HOST_WIDE_INT sc = INTVAL (XEXP (x, 1)); |
2107 | unsigned HOST_WIDE_INT uc = sc; | |
2108 | if (xsize > 0 && sc < 0 && -uc == (uc & -uc)) | |
2109 | { | |
2110 | xsize -= sc + 1; | |
fe8fb1c4 | 2111 | c -= sc + 1; |
a9bf4fe2 AO |
2112 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), |
2113 | ysize, y, c); | |
2114 | } | |
56ee9281 | 2115 | } |
481683e1 | 2116 | if (GET_CODE (y) == AND && CONST_INT_P (XEXP (y, 1))) |
c02f035f | 2117 | { |
a9bf4fe2 AO |
2118 | HOST_WIDE_INT sc = INTVAL (XEXP (y, 1)); |
2119 | unsigned HOST_WIDE_INT uc = sc; | |
2120 | if (ysize > 0 && sc < 0 && -uc == (uc & -uc)) | |
2121 | { | |
2122 | ysize -= sc + 1; | |
fe8fb1c4 | 2123 | c += sc + 1; |
a9bf4fe2 AO |
2124 | return memrefs_conflict_p (xsize, x, |
2125 | ysize, canon_rtx (XEXP (y, 0)), c); | |
2126 | } | |
c02f035f | 2127 | } |
9ae8ffe7 JL |
2128 | |
2129 | if (CONSTANT_P (x)) | |
2130 | { | |
481683e1 | 2131 | if (CONST_INT_P (x) && CONST_INT_P (y)) |
9ae8ffe7 JL |
2132 | { |
2133 | c += (INTVAL (y) - INTVAL (x)); | |
c02f035f | 2134 | return (xsize <= 0 || ysize <= 0 |
9ae8ffe7 JL |
2135 | || (c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)); |
2136 | } | |
2137 | ||
2138 | if (GET_CODE (x) == CONST) | |
2139 | { | |
2140 | if (GET_CODE (y) == CONST) | |
2141 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), | |
2142 | ysize, canon_rtx (XEXP (y, 0)), c); | |
2143 | else | |
2144 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), | |
2145 | ysize, y, c); | |
2146 | } | |
2147 | if (GET_CODE (y) == CONST) | |
2148 | return memrefs_conflict_p (xsize, x, ysize, | |
2149 | canon_rtx (XEXP (y, 0)), c); | |
2150 | ||
2151 | if (CONSTANT_P (y)) | |
b949ea8b | 2152 | return (xsize <= 0 || ysize <= 0 |
c02f035f | 2153 | || (rtx_equal_for_memref_p (x, y) |
b949ea8b | 2154 | && ((c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)))); |
9ae8ffe7 | 2155 | |
f47e08d9 | 2156 | return -1; |
9ae8ffe7 | 2157 | } |
f47e08d9 RG |
2158 | |
2159 | return -1; | |
9ae8ffe7 JL |
2160 | } |
2161 | ||
2162 | /* Functions to compute memory dependencies. | |
2163 | ||
2164 | Since we process the insns in execution order, we can build tables | |
2165 | to keep track of what registers are fixed (and not aliased), what registers | |
2166 | are varying in known ways, and what registers are varying in unknown | |
2167 | ways. | |
2168 | ||
2169 | If both memory references are volatile, then there must always be a | |
2170 | dependence between the two references, since their order can not be | |
2171 | changed. A volatile and non-volatile reference can be interchanged | |
ca7fd9cd | 2172 | though. |
9ae8ffe7 | 2173 | |
53d9622b RS |
2174 | We also must allow AND addresses, because they may generate accesses |
2175 | outside the object being referenced. This is used to generate aligned | |
2176 | addresses from unaligned addresses, for instance, the alpha | |
dc1618bc | 2177 | storeqi_unaligned pattern. */ |
9ae8ffe7 JL |
2178 | |
2179 | /* Read dependence: X is read after read in MEM takes place. There can | |
96672a3e RH |
2180 | only be a dependence here if both reads are volatile, or if either is |
2181 | an explicit barrier. */ | |
9ae8ffe7 JL |
2182 | |
2183 | int | |
4f588890 | 2184 | read_dependence (const_rtx mem, const_rtx x) |
9ae8ffe7 | 2185 | { |
96672a3e RH |
2186 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) |
2187 | return true; | |
2188 | if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER | |
2189 | || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER) | |
2190 | return true; | |
2191 | return false; | |
9ae8ffe7 JL |
2192 | } |
2193 | ||
998d7deb RH |
2194 | /* Return true if we can determine that the fields referenced cannot |
2195 | overlap for any pair of objects. */ | |
2196 | ||
2197 | static bool | |
175a7536 | 2198 | nonoverlapping_component_refs_p (const_rtx rtlx, const_rtx rtly) |
998d7deb | 2199 | { |
175a7536 | 2200 | const_tree x = MEM_EXPR (rtlx), y = MEM_EXPR (rtly); |
4f588890 | 2201 | const_tree fieldx, fieldy, typex, typey, orig_y; |
998d7deb | 2202 | |
175a7536 MM |
2203 | if (!flag_strict_aliasing |
2204 | || !x || !y | |
2205 | || TREE_CODE (x) != COMPONENT_REF | |
2206 | || TREE_CODE (y) != COMPONENT_REF) | |
4c7af939 AB |
2207 | return false; |
2208 | ||
998d7deb RH |
2209 | do |
2210 | { | |
2211 | /* The comparison has to be done at a common type, since we don't | |
d6a7951f | 2212 | know how the inheritance hierarchy works. */ |
998d7deb RH |
2213 | orig_y = y; |
2214 | do | |
2215 | { | |
2216 | fieldx = TREE_OPERAND (x, 1); | |
c05a0766 | 2217 | typex = TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (fieldx)); |
998d7deb RH |
2218 | |
2219 | y = orig_y; | |
2220 | do | |
2221 | { | |
2222 | fieldy = TREE_OPERAND (y, 1); | |
c05a0766 | 2223 | typey = TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (fieldy)); |
998d7deb RH |
2224 | |
2225 | if (typex == typey) | |
2226 | goto found; | |
2227 | ||
2228 | y = TREE_OPERAND (y, 0); | |
2229 | } | |
2230 | while (y && TREE_CODE (y) == COMPONENT_REF); | |
2231 | ||
2232 | x = TREE_OPERAND (x, 0); | |
2233 | } | |
2234 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
998d7deb | 2235 | /* Never found a common type. */ |
c05a0766 | 2236 | return false; |
998d7deb RH |
2237 | |
2238 | found: | |
2239 | /* If we're left with accessing different fields of a structure, | |
2240 | then no overlap. */ | |
2241 | if (TREE_CODE (typex) == RECORD_TYPE | |
2242 | && fieldx != fieldy) | |
2243 | return true; | |
2244 | ||
2245 | /* The comparison on the current field failed. If we're accessing | |
2246 | a very nested structure, look at the next outer level. */ | |
2247 | x = TREE_OPERAND (x, 0); | |
2248 | y = TREE_OPERAND (y, 0); | |
2249 | } | |
2250 | while (x && y | |
2251 | && TREE_CODE (x) == COMPONENT_REF | |
2252 | && TREE_CODE (y) == COMPONENT_REF); | |
ca7fd9cd | 2253 | |
998d7deb RH |
2254 | return false; |
2255 | } | |
2256 | ||
2257 | /* Look at the bottom of the COMPONENT_REF list for a DECL, and return it. */ | |
2258 | ||
2259 | static tree | |
4682ae04 | 2260 | decl_for_component_ref (tree x) |
998d7deb RH |
2261 | { |
2262 | do | |
2263 | { | |
2264 | x = TREE_OPERAND (x, 0); | |
2265 | } | |
2266 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
2267 | ||
2268 | return x && DECL_P (x) ? x : NULL_TREE; | |
2269 | } | |
2270 | ||
527210c4 RS |
2271 | /* Walk up the COMPONENT_REF list in X and adjust *OFFSET to compensate |
2272 | for the offset of the field reference. *KNOWN_P says whether the | |
2273 | offset is known. */ | |
998d7deb | 2274 | |
527210c4 RS |
2275 | static void |
2276 | adjust_offset_for_component_ref (tree x, bool *known_p, | |
2277 | HOST_WIDE_INT *offset) | |
998d7deb | 2278 | { |
527210c4 RS |
2279 | if (!*known_p) |
2280 | return; | |
ca7fd9cd | 2281 | do |
998d7deb | 2282 | { |
527210c4 | 2283 | tree xoffset = component_ref_field_offset (x); |
998d7deb RH |
2284 | tree field = TREE_OPERAND (x, 1); |
2285 | ||
527210c4 RS |
2286 | if (! host_integerp (xoffset, 1)) |
2287 | { | |
2288 | *known_p = false; | |
2289 | return; | |
2290 | } | |
2291 | *offset += (tree_low_cst (xoffset, 1) | |
998d7deb RH |
2292 | + (tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1) |
2293 | / BITS_PER_UNIT)); | |
2294 | ||
2295 | x = TREE_OPERAND (x, 0); | |
2296 | } | |
2297 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
998d7deb RH |
2298 | } |
2299 | ||
95bd1dd7 | 2300 | /* Return nonzero if we can determine the exprs corresponding to memrefs |
c6ea834c BM |
2301 | X and Y and they do not overlap. |
2302 | If LOOP_VARIANT is set, skip offset-based disambiguation */ | |
a4311dfe | 2303 | |
2e4e39f6 | 2304 | int |
c6ea834c | 2305 | nonoverlapping_memrefs_p (const_rtx x, const_rtx y, bool loop_invariant) |
a4311dfe | 2306 | { |
998d7deb | 2307 | tree exprx = MEM_EXPR (x), expry = MEM_EXPR (y); |
a4311dfe RK |
2308 | rtx rtlx, rtly; |
2309 | rtx basex, basey; | |
527210c4 RS |
2310 | bool moffsetx_known_p, moffsety_known_p; |
2311 | HOST_WIDE_INT moffsetx = 0, moffsety = 0; | |
a4311dfe RK |
2312 | HOST_WIDE_INT offsetx = 0, offsety = 0, sizex, sizey, tem; |
2313 | ||
998d7deb RH |
2314 | /* Unless both have exprs, we can't tell anything. */ |
2315 | if (exprx == 0 || expry == 0) | |
2316 | return 0; | |
2b22e382 RG |
2317 | |
2318 | /* For spill-slot accesses make sure we have valid offsets. */ | |
2319 | if ((exprx == get_spill_slot_decl (false) | |
527210c4 | 2320 | && ! MEM_OFFSET_KNOWN_P (x)) |
2b22e382 | 2321 | || (expry == get_spill_slot_decl (false) |
527210c4 | 2322 | && ! MEM_OFFSET_KNOWN_P (y))) |
2b22e382 | 2323 | return 0; |
c22cacf3 | 2324 | |
998d7deb | 2325 | /* If the field reference test failed, look at the DECLs involved. */ |
527210c4 RS |
2326 | moffsetx_known_p = MEM_OFFSET_KNOWN_P (x); |
2327 | if (moffsetx_known_p) | |
2328 | moffsetx = MEM_OFFSET (x); | |
998d7deb RH |
2329 | if (TREE_CODE (exprx) == COMPONENT_REF) |
2330 | { | |
2e0c984c RG |
2331 | tree t = decl_for_component_ref (exprx); |
2332 | if (! t) | |
2333 | return 0; | |
527210c4 | 2334 | adjust_offset_for_component_ref (exprx, &moffsetx_known_p, &moffsetx); |
2e0c984c | 2335 | exprx = t; |
998d7deb | 2336 | } |
c67a1cf6 | 2337 | |
527210c4 RS |
2338 | moffsety_known_p = MEM_OFFSET_KNOWN_P (y); |
2339 | if (moffsety_known_p) | |
2340 | moffsety = MEM_OFFSET (y); | |
998d7deb RH |
2341 | if (TREE_CODE (expry) == COMPONENT_REF) |
2342 | { | |
2e0c984c RG |
2343 | tree t = decl_for_component_ref (expry); |
2344 | if (! t) | |
2345 | return 0; | |
527210c4 | 2346 | adjust_offset_for_component_ref (expry, &moffsety_known_p, &moffsety); |
2e0c984c | 2347 | expry = t; |
998d7deb RH |
2348 | } |
2349 | ||
2350 | if (! DECL_P (exprx) || ! DECL_P (expry)) | |
a4311dfe RK |
2351 | return 0; |
2352 | ||
1307c758 RG |
2353 | /* With invalid code we can end up storing into the constant pool. |
2354 | Bail out to avoid ICEing when creating RTL for this. | |
2355 | See gfortran.dg/lto/20091028-2_0.f90. */ | |
2356 | if (TREE_CODE (exprx) == CONST_DECL | |
2357 | || TREE_CODE (expry) == CONST_DECL) | |
2358 | return 1; | |
2359 | ||
998d7deb RH |
2360 | rtlx = DECL_RTL (exprx); |
2361 | rtly = DECL_RTL (expry); | |
a4311dfe | 2362 | |
1edcd60b RK |
2363 | /* If either RTL is not a MEM, it must be a REG or CONCAT, meaning they |
2364 | can't overlap unless they are the same because we never reuse that part | |
2365 | of the stack frame used for locals for spilled pseudos. */ | |
3c0cb5de | 2366 | if ((!MEM_P (rtlx) || !MEM_P (rtly)) |
1edcd60b | 2367 | && ! rtx_equal_p (rtlx, rtly)) |
a4311dfe RK |
2368 | return 1; |
2369 | ||
5932a4d4 | 2370 | /* If we have MEMs referring to different address spaces (which can |
09e881c9 BE |
2371 | potentially overlap), we cannot easily tell from the addresses |
2372 | whether the references overlap. */ | |
2373 | if (MEM_P (rtlx) && MEM_P (rtly) | |
2374 | && MEM_ADDR_SPACE (rtlx) != MEM_ADDR_SPACE (rtly)) | |
2375 | return 0; | |
2376 | ||
a4311dfe RK |
2377 | /* Get the base and offsets of both decls. If either is a register, we |
2378 | know both are and are the same, so use that as the base. The only | |
2379 | we can avoid overlap is if we can deduce that they are nonoverlapping | |
2380 | pieces of that decl, which is very rare. */ | |
3c0cb5de | 2381 | basex = MEM_P (rtlx) ? XEXP (rtlx, 0) : rtlx; |
481683e1 | 2382 | if (GET_CODE (basex) == PLUS && CONST_INT_P (XEXP (basex, 1))) |
a4311dfe RK |
2383 | offsetx = INTVAL (XEXP (basex, 1)), basex = XEXP (basex, 0); |
2384 | ||
3c0cb5de | 2385 | basey = MEM_P (rtly) ? XEXP (rtly, 0) : rtly; |
481683e1 | 2386 | if (GET_CODE (basey) == PLUS && CONST_INT_P (XEXP (basey, 1))) |
a4311dfe RK |
2387 | offsety = INTVAL (XEXP (basey, 1)), basey = XEXP (basey, 0); |
2388 | ||
d746694a | 2389 | /* If the bases are different, we know they do not overlap if both |
ca7fd9cd | 2390 | are constants or if one is a constant and the other a pointer into the |
d746694a RK |
2391 | stack frame. Otherwise a different base means we can't tell if they |
2392 | overlap or not. */ | |
2393 | if (! rtx_equal_p (basex, basey)) | |
ca7fd9cd KH |
2394 | return ((CONSTANT_P (basex) && CONSTANT_P (basey)) |
2395 | || (CONSTANT_P (basex) && REG_P (basey) | |
2396 | && REGNO_PTR_FRAME_P (REGNO (basey))) | |
2397 | || (CONSTANT_P (basey) && REG_P (basex) | |
2398 | && REGNO_PTR_FRAME_P (REGNO (basex)))); | |
a4311dfe | 2399 | |
c6ea834c BM |
2400 | /* Offset based disambiguation not appropriate for loop invariant */ |
2401 | if (loop_invariant) | |
2402 | return 0; | |
2403 | ||
3c0cb5de | 2404 | sizex = (!MEM_P (rtlx) ? (int) GET_MODE_SIZE (GET_MODE (rtlx)) |
f5541398 | 2405 | : MEM_SIZE_KNOWN_P (rtlx) ? MEM_SIZE (rtlx) |
a4311dfe | 2406 | : -1); |
3c0cb5de | 2407 | sizey = (!MEM_P (rtly) ? (int) GET_MODE_SIZE (GET_MODE (rtly)) |
f5541398 RS |
2408 | : MEM_SIZE_KNOWN_P (rtly) ? MEM_SIZE (rtly) |
2409 | : -1); | |
a4311dfe | 2410 | |
0af5bc3e RK |
2411 | /* If we have an offset for either memref, it can update the values computed |
2412 | above. */ | |
527210c4 RS |
2413 | if (moffsetx_known_p) |
2414 | offsetx += moffsetx, sizex -= moffsetx; | |
2415 | if (moffsety_known_p) | |
2416 | offsety += moffsety, sizey -= moffsety; | |
a4311dfe | 2417 | |
0af5bc3e | 2418 | /* If a memref has both a size and an offset, we can use the smaller size. |
efc981bb | 2419 | We can't do this if the offset isn't known because we must view this |
0af5bc3e | 2420 | memref as being anywhere inside the DECL's MEM. */ |
527210c4 | 2421 | if (MEM_SIZE_KNOWN_P (x) && moffsetx_known_p) |
f5541398 | 2422 | sizex = MEM_SIZE (x); |
527210c4 | 2423 | if (MEM_SIZE_KNOWN_P (y) && moffsety_known_p) |
f5541398 | 2424 | sizey = MEM_SIZE (y); |
a4311dfe RK |
2425 | |
2426 | /* Put the values of the memref with the lower offset in X's values. */ | |
2427 | if (offsetx > offsety) | |
2428 | { | |
2429 | tem = offsetx, offsetx = offsety, offsety = tem; | |
2430 | tem = sizex, sizex = sizey, sizey = tem; | |
2431 | } | |
2432 | ||
2433 | /* If we don't know the size of the lower-offset value, we can't tell | |
2434 | if they conflict. Otherwise, we do the test. */ | |
a6f7c915 | 2435 | return sizex >= 0 && offsety >= offsetx + sizex; |
a4311dfe RK |
2436 | } |
2437 | ||
9362286d SB |
2438 | /* Helper for true_dependence and canon_true_dependence. |
2439 | Checks for true dependence: X is read after store in MEM takes place. | |
9ae8ffe7 | 2440 | |
9362286d SB |
2441 | If MEM_CANONICALIZED is FALSE, then X_ADDR and MEM_ADDR should be |
2442 | NULL_RTX, and the canonical addresses of MEM and X are both computed | |
2443 | here. If MEM_CANONICALIZED, then MEM must be already canonicalized. | |
2444 | ||
2445 | If X_ADDR is non-NULL, it is used in preference of XEXP (x, 0). | |
2446 | ||
2447 | Returns 1 if there is a true dependence, 0 otherwise. */ | |
2448 | ||
2449 | static int | |
2450 | true_dependence_1 (const_rtx mem, enum machine_mode mem_mode, rtx mem_addr, | |
53d9622b | 2451 | const_rtx x, rtx x_addr, bool mem_canonicalized) |
9ae8ffe7 | 2452 | { |
49982682 | 2453 | rtx base; |
f47e08d9 | 2454 | int ret; |
9ae8ffe7 | 2455 | |
9362286d SB |
2456 | gcc_checking_assert (mem_canonicalized ? (mem_addr != NULL_RTX) |
2457 | : (mem_addr == NULL_RTX && x_addr == NULL_RTX)); | |
2458 | ||
9ae8ffe7 JL |
2459 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) |
2460 | return 1; | |
2461 | ||
c4484b8f | 2462 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
ac3768f6 | 2463 | This is used in epilogue deallocation functions, and in cselib. */ |
c4484b8f RH |
2464 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) |
2465 | return 1; | |
2466 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
2467 | return 1; | |
9cd9e512 RH |
2468 | if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER |
2469 | || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER) | |
2470 | return 1; | |
c4484b8f | 2471 | |
389fdba0 RH |
2472 | /* Read-only memory is by definition never modified, and therefore can't |
2473 | conflict with anything. We don't expect to find read-only set on MEM, | |
41806d92 | 2474 | but stupid user tricks can produce them, so don't die. */ |
389fdba0 | 2475 | if (MEM_READONLY_P (x)) |
9ae8ffe7 JL |
2476 | return 0; |
2477 | ||
5932a4d4 | 2478 | /* If we have MEMs referring to different address spaces (which can |
09e881c9 BE |
2479 | potentially overlap), we cannot easily tell from the addresses |
2480 | whether the references overlap. */ | |
2481 | if (MEM_ADDR_SPACE (mem) != MEM_ADDR_SPACE (x)) | |
2482 | return 1; | |
2483 | ||
9362286d SB |
2484 | if (! mem_addr) |
2485 | { | |
2486 | mem_addr = XEXP (mem, 0); | |
2487 | if (mem_mode == VOIDmode) | |
2488 | mem_mode = GET_MODE (mem); | |
2489 | } | |
2490 | ||
2491 | if (! x_addr) | |
2147c71c | 2492 | { |
a522de15 SB |
2493 | x_addr = XEXP (x, 0); |
2494 | if (!((GET_CODE (x_addr) == VALUE | |
2495 | && GET_CODE (mem_addr) != VALUE | |
2496 | && reg_mentioned_p (x_addr, mem_addr)) | |
2497 | || (GET_CODE (x_addr) != VALUE | |
2498 | && GET_CODE (mem_addr) == VALUE | |
2499 | && reg_mentioned_p (mem_addr, x_addr)))) | |
2500 | { | |
2501 | x_addr = get_addr (x_addr); | |
2502 | if (! mem_canonicalized) | |
2503 | mem_addr = get_addr (mem_addr); | |
2504 | } | |
2147c71c | 2505 | } |
eab5c70a | 2506 | |
55efb413 JW |
2507 | base = find_base_term (x_addr); |
2508 | if (base && (GET_CODE (base) == LABEL_REF | |
2509 | || (GET_CODE (base) == SYMBOL_REF | |
2510 | && CONSTANT_POOL_ADDRESS_P (base)))) | |
2511 | return 0; | |
2512 | ||
eab5c70a | 2513 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), mem_mode)) |
1c72c7f6 JC |
2514 | return 0; |
2515 | ||
eab5c70a | 2516 | x_addr = canon_rtx (x_addr); |
9362286d SB |
2517 | if (!mem_canonicalized) |
2518 | mem_addr = canon_rtx (mem_addr); | |
6e73e666 | 2519 | |
f47e08d9 RG |
2520 | if ((ret = memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr, |
2521 | SIZE_FOR_MODE (x), x_addr, 0)) != -1) | |
2522 | return ret; | |
2523 | ||
a95b3cc7 | 2524 | if (mems_in_disjoint_alias_sets_p (x, mem)) |
f47e08d9 RG |
2525 | return 0; |
2526 | ||
c6ea834c | 2527 | if (nonoverlapping_memrefs_p (mem, x, false)) |
0211b6ab | 2528 | return 0; |
175a7536 MM |
2529 | |
2530 | if (nonoverlapping_component_refs_p (mem, x)) | |
2531 | return 0; | |
0211b6ab | 2532 | |
55b34b5f | 2533 | return rtx_refs_may_alias_p (x, mem, true); |
a13d4ebf AM |
2534 | } |
2535 | ||
9362286d SB |
2536 | /* True dependence: X is read after store in MEM takes place. */ |
2537 | ||
2538 | int | |
53d9622b | 2539 | true_dependence (const_rtx mem, enum machine_mode mem_mode, const_rtx x) |
9362286d SB |
2540 | { |
2541 | return true_dependence_1 (mem, mem_mode, NULL_RTX, | |
53d9622b | 2542 | x, NULL_RTX, /*mem_canonicalized=*/false); |
9362286d SB |
2543 | } |
2544 | ||
a13d4ebf | 2545 | /* Canonical true dependence: X is read after store in MEM takes place. |
ca7fd9cd KH |
2546 | Variant of true_dependence which assumes MEM has already been |
2547 | canonicalized (hence we no longer do that here). | |
9362286d SB |
2548 | The mem_addr argument has been added, since true_dependence_1 computed |
2549 | this value prior to canonicalizing. */ | |
a13d4ebf AM |
2550 | |
2551 | int | |
4f588890 | 2552 | canon_true_dependence (const_rtx mem, enum machine_mode mem_mode, rtx mem_addr, |
53d9622b | 2553 | const_rtx x, rtx x_addr) |
a13d4ebf | 2554 | { |
9362286d | 2555 | return true_dependence_1 (mem, mem_mode, mem_addr, |
53d9622b | 2556 | x, x_addr, /*mem_canonicalized=*/true); |
9ae8ffe7 JL |
2557 | } |
2558 | ||
da7d8304 | 2559 | /* Returns nonzero if a write to X might alias a previous read from |
389fdba0 | 2560 | (or, if WRITEP is nonzero, a write to) MEM. */ |
9ae8ffe7 | 2561 | |
2c72b78f | 2562 | static int |
4f588890 | 2563 | write_dependence_p (const_rtx mem, const_rtx x, int writep) |
9ae8ffe7 | 2564 | { |
6e73e666 | 2565 | rtx x_addr, mem_addr; |
49982682 | 2566 | rtx base; |
f47e08d9 | 2567 | int ret; |
6e73e666 | 2568 | |
9ae8ffe7 JL |
2569 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) |
2570 | return 1; | |
2571 | ||
c4484b8f RH |
2572 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
2573 | This is used in epilogue deallocation functions. */ | |
2574 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) | |
2575 | return 1; | |
2576 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
2577 | return 1; | |
9cd9e512 RH |
2578 | if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER |
2579 | || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER) | |
2580 | return 1; | |
c4484b8f | 2581 | |
389fdba0 RH |
2582 | /* A read from read-only memory can't conflict with read-write memory. */ |
2583 | if (!writep && MEM_READONLY_P (mem)) | |
2584 | return 0; | |
55efb413 | 2585 | |
5932a4d4 | 2586 | /* If we have MEMs referring to different address spaces (which can |
09e881c9 BE |
2587 | potentially overlap), we cannot easily tell from the addresses |
2588 | whether the references overlap. */ | |
2589 | if (MEM_ADDR_SPACE (mem) != MEM_ADDR_SPACE (x)) | |
2590 | return 1; | |
2591 | ||
2147c71c L |
2592 | x_addr = XEXP (x, 0); |
2593 | mem_addr = XEXP (mem, 0); | |
2594 | if (!((GET_CODE (x_addr) == VALUE | |
2595 | && GET_CODE (mem_addr) != VALUE | |
2596 | && reg_mentioned_p (x_addr, mem_addr)) | |
2597 | || (GET_CODE (x_addr) != VALUE | |
2598 | && GET_CODE (mem_addr) == VALUE | |
2599 | && reg_mentioned_p (mem_addr, x_addr)))) | |
2600 | { | |
2601 | x_addr = get_addr (x_addr); | |
2602 | mem_addr = get_addr (mem_addr); | |
2603 | } | |
55efb413 | 2604 | |
49982682 JW |
2605 | if (! writep) |
2606 | { | |
55efb413 | 2607 | base = find_base_term (mem_addr); |
49982682 JW |
2608 | if (base && (GET_CODE (base) == LABEL_REF |
2609 | || (GET_CODE (base) == SYMBOL_REF | |
2610 | && CONSTANT_POOL_ADDRESS_P (base)))) | |
2611 | return 0; | |
2612 | } | |
2613 | ||
eab5c70a BS |
2614 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), |
2615 | GET_MODE (mem))) | |
41472af8 MM |
2616 | return 0; |
2617 | ||
eab5c70a BS |
2618 | x_addr = canon_rtx (x_addr); |
2619 | mem_addr = canon_rtx (mem_addr); | |
6e73e666 | 2620 | |
f47e08d9 RG |
2621 | if ((ret = memrefs_conflict_p (SIZE_FOR_MODE (mem), mem_addr, |
2622 | SIZE_FOR_MODE (x), x_addr, 0)) != -1) | |
2623 | return ret; | |
2624 | ||
c6ea834c | 2625 | if (nonoverlapping_memrefs_p (x, mem, false)) |
c6df88cb MM |
2626 | return 0; |
2627 | ||
55b34b5f | 2628 | return rtx_refs_may_alias_p (x, mem, false); |
c6df88cb MM |
2629 | } |
2630 | ||
2631 | /* Anti dependence: X is written after read in MEM takes place. */ | |
2632 | ||
2633 | int | |
4f588890 | 2634 | anti_dependence (const_rtx mem, const_rtx x) |
c6df88cb | 2635 | { |
389fdba0 | 2636 | return write_dependence_p (mem, x, /*writep=*/0); |
9ae8ffe7 JL |
2637 | } |
2638 | ||
2639 | /* Output dependence: X is written after store in MEM takes place. */ | |
2640 | ||
2641 | int | |
4f588890 | 2642 | output_dependence (const_rtx mem, const_rtx x) |
9ae8ffe7 | 2643 | { |
389fdba0 | 2644 | return write_dependence_p (mem, x, /*writep=*/1); |
9ae8ffe7 | 2645 | } |
c14b9960 | 2646 | \f |
6e73e666 | 2647 | |
c6ea834c BM |
2648 | |
2649 | /* Check whether X may be aliased with MEM. Don't do offset-based | |
2650 | memory disambiguation & TBAA. */ | |
2651 | int | |
2652 | may_alias_p (const_rtx mem, const_rtx x) | |
2653 | { | |
2654 | rtx x_addr, mem_addr; | |
c6ea834c BM |
2655 | |
2656 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) | |
2657 | return 1; | |
2658 | ||
a95b3cc7 RG |
2659 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
2660 | This is used in epilogue deallocation functions. */ | |
2661 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) | |
2662 | return 1; | |
2663 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
c6ea834c | 2664 | return 1; |
c6ea834c BM |
2665 | if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER |
2666 | || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER) | |
2667 | return 1; | |
2668 | ||
2669 | /* Read-only memory is by definition never modified, and therefore can't | |
2670 | conflict with anything. We don't expect to find read-only set on MEM, | |
2671 | but stupid user tricks can produce them, so don't die. */ | |
2672 | if (MEM_READONLY_P (x)) | |
2673 | return 0; | |
2674 | ||
5932a4d4 | 2675 | /* If we have MEMs referring to different address spaces (which can |
c6ea834c BM |
2676 | potentially overlap), we cannot easily tell from the addresses |
2677 | whether the references overlap. */ | |
2678 | if (MEM_ADDR_SPACE (mem) != MEM_ADDR_SPACE (x)) | |
2679 | return 1; | |
2680 | ||
2681 | x_addr = XEXP (x, 0); | |
2682 | mem_addr = XEXP (mem, 0); | |
2683 | if (!((GET_CODE (x_addr) == VALUE | |
2684 | && GET_CODE (mem_addr) != VALUE | |
2685 | && reg_mentioned_p (x_addr, mem_addr)) | |
2686 | || (GET_CODE (x_addr) != VALUE | |
2687 | && GET_CODE (mem_addr) == VALUE | |
2688 | && reg_mentioned_p (mem_addr, x_addr)))) | |
2689 | { | |
2690 | x_addr = get_addr (x_addr); | |
2691 | mem_addr = get_addr (mem_addr); | |
2692 | } | |
2693 | ||
2694 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), GET_MODE (mem_addr))) | |
2695 | return 0; | |
2696 | ||
2697 | x_addr = canon_rtx (x_addr); | |
2698 | mem_addr = canon_rtx (mem_addr); | |
2699 | ||
2700 | if (nonoverlapping_memrefs_p (mem, x, true)) | |
2701 | return 0; | |
2702 | ||
c6ea834c BM |
2703 | /* TBAA not valid for loop_invarint */ |
2704 | return rtx_refs_may_alias_p (x, mem, false); | |
2705 | } | |
2706 | ||
6e73e666 | 2707 | void |
b5deb7b6 | 2708 | init_alias_target (void) |
6e73e666 | 2709 | { |
b3694847 | 2710 | int i; |
6e73e666 | 2711 | |
9fc37b2b RS |
2712 | if (!arg_base_value) |
2713 | arg_base_value = gen_rtx_ADDRESS (VOIDmode, 0); | |
2714 | ||
b5deb7b6 SL |
2715 | memset (static_reg_base_value, 0, sizeof static_reg_base_value); |
2716 | ||
6e73e666 JC |
2717 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) |
2718 | /* Check whether this register can hold an incoming pointer | |
2719 | argument. FUNCTION_ARG_REGNO_P tests outgoing register | |
ec5c56db | 2720 | numbers, so translate if necessary due to register windows. */ |
6e73e666 JC |
2721 | if (FUNCTION_ARG_REGNO_P (OUTGOING_REGNO (i)) |
2722 | && HARD_REGNO_MODE_OK (i, Pmode)) | |
9fc37b2b RS |
2723 | static_reg_base_value[i] = arg_base_value; |
2724 | ||
757e8ba2 JJ |
2725 | static_reg_base_value[STACK_POINTER_REGNUM] |
2726 | = unique_base_value (UNIQUE_BASE_VALUE_SP); | |
2727 | static_reg_base_value[ARG_POINTER_REGNUM] | |
2728 | = unique_base_value (UNIQUE_BASE_VALUE_ARGP); | |
2729 | static_reg_base_value[FRAME_POINTER_REGNUM] | |
2730 | = unique_base_value (UNIQUE_BASE_VALUE_FP); | |
e3339d0f | 2731 | #if !HARD_FRAME_POINTER_IS_FRAME_POINTER |
757e8ba2 JJ |
2732 | static_reg_base_value[HARD_FRAME_POINTER_REGNUM] |
2733 | = unique_base_value (UNIQUE_BASE_VALUE_HFP); | |
bf1660a6 JL |
2734 | #endif |
2735 | } | |
2736 | ||
7b52eede JH |
2737 | /* Set MEMORY_MODIFIED when X modifies DATA (that is assumed |
2738 | to be memory reference. */ | |
2739 | static bool memory_modified; | |
2740 | static void | |
aa317c97 | 2741 | memory_modified_1 (rtx x, const_rtx pat ATTRIBUTE_UNUSED, void *data) |
7b52eede | 2742 | { |
3c0cb5de | 2743 | if (MEM_P (x)) |
7b52eede | 2744 | { |
9678086d | 2745 | if (anti_dependence (x, (const_rtx)data) || output_dependence (x, (const_rtx)data)) |
7b52eede JH |
2746 | memory_modified = true; |
2747 | } | |
2748 | } | |
2749 | ||
2750 | ||
2751 | /* Return true when INSN possibly modify memory contents of MEM | |
454ff5cb | 2752 | (i.e. address can be modified). */ |
7b52eede | 2753 | bool |
9678086d | 2754 | memory_modified_in_insn_p (const_rtx mem, const_rtx insn) |
7b52eede JH |
2755 | { |
2756 | if (!INSN_P (insn)) | |
2757 | return false; | |
2758 | memory_modified = false; | |
aa317c97 | 2759 | note_stores (PATTERN (insn), memory_modified_1, CONST_CAST_RTX(mem)); |
7b52eede JH |
2760 | return memory_modified; |
2761 | } | |
2762 | ||
c13e8210 MM |
2763 | /* Initialize the aliasing machinery. Initialize the REG_KNOWN_VALUE |
2764 | array. */ | |
2765 | ||
9ae8ffe7 | 2766 | void |
4682ae04 | 2767 | init_alias_analysis (void) |
9ae8ffe7 | 2768 | { |
c582d54a | 2769 | unsigned int maxreg = max_reg_num (); |
ea64ef27 | 2770 | int changed, pass; |
b3694847 SS |
2771 | int i; |
2772 | unsigned int ui; | |
9ff3c7ca | 2773 | rtx insn, val; |
131db6b8 SB |
2774 | int rpo_cnt; |
2775 | int *rpo; | |
9ae8ffe7 | 2776 | |
0d446150 JH |
2777 | timevar_push (TV_ALIAS_ANALYSIS); |
2778 | ||
9ff3c7ca SB |
2779 | reg_known_value = VEC_alloc (rtx, gc, maxreg - FIRST_PSEUDO_REGISTER); |
2780 | reg_known_equiv_p = sbitmap_alloc (maxreg - FIRST_PSEUDO_REGISTER); | |
9ae8ffe7 | 2781 | |
08c79682 | 2782 | /* If we have memory allocated from the previous run, use it. */ |
c582d54a | 2783 | if (old_reg_base_value) |
08c79682 KH |
2784 | reg_base_value = old_reg_base_value; |
2785 | ||
2786 | if (reg_base_value) | |
2787 | VEC_truncate (rtx, reg_base_value, 0); | |
2788 | ||
a590ac65 | 2789 | VEC_safe_grow_cleared (rtx, gc, reg_base_value, maxreg); |
ac606739 | 2790 | |
5ed6ace5 | 2791 | new_reg_base_value = XNEWVEC (rtx, maxreg); |
d630245f | 2792 | reg_seen = sbitmap_alloc (maxreg); |
ec907dd8 JL |
2793 | |
2794 | /* The basic idea is that each pass through this loop will use the | |
2795 | "constant" information from the previous pass to propagate alias | |
2796 | information through another level of assignments. | |
2797 | ||
131db6b8 SB |
2798 | The propagation is done on the CFG in reverse post-order, to propagate |
2799 | things forward as far as possible in each iteration. | |
2800 | ||
ec907dd8 JL |
2801 | This could get expensive if the assignment chains are long. Maybe |
2802 | we should throttle the number of iterations, possibly based on | |
6e73e666 | 2803 | the optimization level or flag_expensive_optimizations. |
ec907dd8 JL |
2804 | |
2805 | We could propagate more information in the first pass by making use | |
6fb5fa3c | 2806 | of DF_REG_DEF_COUNT to determine immediately that the alias information |
ea64ef27 JL |
2807 | for a pseudo is "constant". |
2808 | ||
2809 | A program with an uninitialized variable can cause an infinite loop | |
2810 | here. Instead of doing a full dataflow analysis to detect such problems | |
2811 | we just cap the number of iterations for the loop. | |
2812 | ||
2813 | The state of the arrays for the set chain in question does not matter | |
2814 | since the program has undefined behavior. */ | |
6e73e666 | 2815 | |
131db6b8 SB |
2816 | rpo = XNEWVEC (int, n_basic_blocks); |
2817 | rpo_cnt = pre_and_rev_post_order_compute (NULL, rpo, false); | |
2818 | ||
ea64ef27 | 2819 | pass = 0; |
6e73e666 | 2820 | do |
ec907dd8 JL |
2821 | { |
2822 | /* Assume nothing will change this iteration of the loop. */ | |
2823 | changed = 0; | |
2824 | ||
ec907dd8 | 2825 | /* We want to assign the same IDs each iteration of this loop, so |
9fc37b2b RS |
2826 | start counting from one each iteration of the loop. */ |
2827 | unique_id = 1; | |
ec907dd8 | 2828 | |
f5143c46 | 2829 | /* We're at the start of the function each iteration through the |
ec907dd8 | 2830 | loop, so we're copying arguments. */ |
83bbd9b6 | 2831 | copying_arguments = true; |
9ae8ffe7 | 2832 | |
6e73e666 | 2833 | /* Wipe the potential alias information clean for this pass. */ |
c582d54a | 2834 | memset (new_reg_base_value, 0, maxreg * sizeof (rtx)); |
8072f69c | 2835 | |
6e73e666 | 2836 | /* Wipe the reg_seen array clean. */ |
d630245f | 2837 | sbitmap_zero (reg_seen); |
9ae8ffe7 | 2838 | |
6e73e666 JC |
2839 | /* Mark all hard registers which may contain an address. |
2840 | The stack, frame and argument pointers may contain an address. | |
2841 | An argument register which can hold a Pmode value may contain | |
2842 | an address even if it is not in BASE_REGS. | |
8072f69c | 2843 | |
6e73e666 JC |
2844 | The address expression is VOIDmode for an argument and |
2845 | Pmode for other registers. */ | |
2846 | ||
7f243674 JL |
2847 | memcpy (new_reg_base_value, static_reg_base_value, |
2848 | FIRST_PSEUDO_REGISTER * sizeof (rtx)); | |
6e73e666 | 2849 | |
ec907dd8 | 2850 | /* Walk the insns adding values to the new_reg_base_value array. */ |
131db6b8 | 2851 | for (i = 0; i < rpo_cnt; i++) |
9ae8ffe7 | 2852 | { |
131db6b8 SB |
2853 | basic_block bb = BASIC_BLOCK (rpo[i]); |
2854 | FOR_BB_INSNS (bb, insn) | |
ec907dd8 | 2855 | { |
131db6b8 SB |
2856 | if (NONDEBUG_INSN_P (insn)) |
2857 | { | |
2858 | rtx note, set; | |
efc9bd41 RK |
2859 | |
2860 | #if defined (HAVE_prologue) || defined (HAVE_epilogue) | |
131db6b8 SB |
2861 | /* The prologue/epilogue insns are not threaded onto the |
2862 | insn chain until after reload has completed. Thus, | |
2863 | there is no sense wasting time checking if INSN is in | |
2864 | the prologue/epilogue until after reload has completed. */ | |
2865 | if (reload_completed | |
2866 | && prologue_epilogue_contains (insn)) | |
2867 | continue; | |
efc9bd41 RK |
2868 | #endif |
2869 | ||
131db6b8 SB |
2870 | /* If this insn has a noalias note, process it, Otherwise, |
2871 | scan for sets. A simple set will have no side effects | |
2872 | which could change the base value of any other register. */ | |
6e73e666 | 2873 | |
131db6b8 SB |
2874 | if (GET_CODE (PATTERN (insn)) == SET |
2875 | && REG_NOTES (insn) != 0 | |
2876 | && find_reg_note (insn, REG_NOALIAS, NULL_RTX)) | |
2877 | record_set (SET_DEST (PATTERN (insn)), NULL_RTX, NULL); | |
2878 | else | |
2879 | note_stores (PATTERN (insn), record_set, NULL); | |
6e73e666 | 2880 | |
131db6b8 | 2881 | set = single_set (insn); |
6e73e666 | 2882 | |
131db6b8 SB |
2883 | if (set != 0 |
2884 | && REG_P (SET_DEST (set)) | |
2885 | && REGNO (SET_DEST (set)) >= FIRST_PSEUDO_REGISTER) | |
713f41f9 | 2886 | { |
131db6b8 SB |
2887 | unsigned int regno = REGNO (SET_DEST (set)); |
2888 | rtx src = SET_SRC (set); | |
2889 | rtx t; | |
2890 | ||
2891 | note = find_reg_equal_equiv_note (insn); | |
2892 | if (note && REG_NOTE_KIND (note) == REG_EQUAL | |
2893 | && DF_REG_DEF_COUNT (regno) != 1) | |
2894 | note = NULL_RTX; | |
2895 | ||
2896 | if (note != NULL_RTX | |
2897 | && GET_CODE (XEXP (note, 0)) != EXPR_LIST | |
2898 | && ! rtx_varies_p (XEXP (note, 0), 1) | |
2899 | && ! reg_overlap_mentioned_p (SET_DEST (set), | |
2900 | XEXP (note, 0))) | |
2901 | { | |
2902 | set_reg_known_value (regno, XEXP (note, 0)); | |
2903 | set_reg_known_equiv_p (regno, | |
2904 | REG_NOTE_KIND (note) == REG_EQUIV); | |
2905 | } | |
2906 | else if (DF_REG_DEF_COUNT (regno) == 1 | |
2907 | && GET_CODE (src) == PLUS | |
2908 | && REG_P (XEXP (src, 0)) | |
2909 | && (t = get_reg_known_value (REGNO (XEXP (src, 0)))) | |
2910 | && CONST_INT_P (XEXP (src, 1))) | |
2911 | { | |
2912 | t = plus_constant (GET_MODE (src), t, | |
2913 | INTVAL (XEXP (src, 1))); | |
2914 | set_reg_known_value (regno, t); | |
2915 | set_reg_known_equiv_p (regno, false); | |
2916 | } | |
2917 | else if (DF_REG_DEF_COUNT (regno) == 1 | |
2918 | && ! rtx_varies_p (src, 1)) | |
2919 | { | |
2920 | set_reg_known_value (regno, src); | |
2921 | set_reg_known_equiv_p (regno, false); | |
2922 | } | |
713f41f9 | 2923 | } |
6e73e666 | 2924 | } |
131db6b8 SB |
2925 | else if (NOTE_P (insn) |
2926 | && NOTE_KIND (insn) == NOTE_INSN_FUNCTION_BEG) | |
2927 | copying_arguments = false; | |
ec907dd8 | 2928 | } |
6e73e666 | 2929 | } |
ec907dd8 | 2930 | |
6e73e666 | 2931 | /* Now propagate values from new_reg_base_value to reg_base_value. */ |
62e5bf5d | 2932 | gcc_assert (maxreg == (unsigned int) max_reg_num ()); |
c22cacf3 | 2933 | |
c582d54a | 2934 | for (ui = 0; ui < maxreg; ui++) |
6e73e666 | 2935 | { |
e51712db | 2936 | if (new_reg_base_value[ui] |
08c79682 | 2937 | && new_reg_base_value[ui] != VEC_index (rtx, reg_base_value, ui) |
c582d54a | 2938 | && ! rtx_equal_p (new_reg_base_value[ui], |
08c79682 | 2939 | VEC_index (rtx, reg_base_value, ui))) |
ec907dd8 | 2940 | { |
08c79682 | 2941 | VEC_replace (rtx, reg_base_value, ui, new_reg_base_value[ui]); |
6e73e666 | 2942 | changed = 1; |
ec907dd8 | 2943 | } |
9ae8ffe7 | 2944 | } |
9ae8ffe7 | 2945 | } |
6e73e666 | 2946 | while (changed && ++pass < MAX_ALIAS_LOOP_PASSES); |
131db6b8 | 2947 | XDELETEVEC (rpo); |
9ae8ffe7 JL |
2948 | |
2949 | /* Fill in the remaining entries. */ | |
9ff3c7ca SB |
2950 | FOR_EACH_VEC_ELT (rtx, reg_known_value, i, val) |
2951 | { | |
2952 | int regno = i + FIRST_PSEUDO_REGISTER; | |
2953 | if (! val) | |
2954 | set_reg_known_value (regno, regno_reg_rtx[regno]); | |
2955 | } | |
9ae8ffe7 | 2956 | |
e05e2395 MM |
2957 | /* Clean up. */ |
2958 | free (new_reg_base_value); | |
ec907dd8 | 2959 | new_reg_base_value = 0; |
d630245f | 2960 | sbitmap_free (reg_seen); |
9ae8ffe7 | 2961 | reg_seen = 0; |
0d446150 | 2962 | timevar_pop (TV_ALIAS_ANALYSIS); |
9ae8ffe7 JL |
2963 | } |
2964 | ||
61630b27 JJ |
2965 | /* Equate REG_BASE_VALUE (reg1) to REG_BASE_VALUE (reg2). |
2966 | Special API for var-tracking pass purposes. */ | |
2967 | ||
2968 | void | |
2969 | vt_equate_reg_base_value (const_rtx reg1, const_rtx reg2) | |
2970 | { | |
2971 | VEC_replace (rtx, reg_base_value, REGNO (reg1), REG_BASE_VALUE (reg2)); | |
2972 | } | |
2973 | ||
9ae8ffe7 | 2974 | void |
4682ae04 | 2975 | end_alias_analysis (void) |
9ae8ffe7 | 2976 | { |
c582d54a | 2977 | old_reg_base_value = reg_base_value; |
9ff3c7ca SB |
2978 | VEC_free (rtx, gc, reg_known_value); |
2979 | sbitmap_free (reg_known_equiv_p); | |
9ae8ffe7 | 2980 | } |
e2500fed GK |
2981 | |
2982 | #include "gt-alias.h" |