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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 |
ac3d9668 | 171 | information through set chains. 10 is a completely arbitrary choice. */ |
ea64ef27 | 172 | #define MAX_ALIAS_LOOP_PASSES 10 |
ca7fd9cd | 173 | |
9ae8ffe7 JL |
174 | /* reg_base_value[N] gives an address to which register N is related. |
175 | If all sets after the first add or subtract to the current value | |
176 | or otherwise modify it so it does not point to a different top level | |
177 | object, reg_base_value[N] is equal to the address part of the source | |
2a2c8203 JC |
178 | of the first set. |
179 | ||
180 | A base address can be an ADDRESS, SYMBOL_REF, or LABEL_REF. ADDRESS | |
9fc37b2b | 181 | expressions represent three types of base: |
b3b5ad95 | 182 | |
9fc37b2b RS |
183 | 1. incoming arguments. There is just one ADDRESS to represent all |
184 | arguments, since we do not know at this level whether accesses | |
185 | based on different arguments can alias. The ADDRESS has id 0. | |
b3b5ad95 | 186 | |
9fc37b2b RS |
187 | 2. stack_pointer_rtx, frame_pointer_rtx, hard_frame_pointer_rtx |
188 | (if distinct from frame_pointer_rtx) and arg_pointer_rtx. | |
189 | Each of these rtxes has a separate ADDRESS associated with it, | |
190 | each with a negative id. | |
191 | ||
192 | GCC is (and is required to be) precise in which register it | |
193 | chooses to access a particular region of stack. We can therefore | |
194 | assume that accesses based on one of these rtxes do not alias | |
195 | accesses based on another of these rtxes. | |
196 | ||
197 | 3. bases that are derived from malloc()ed memory (REG_NOALIAS). | |
198 | Each such piece of memory has a separate ADDRESS associated | |
199 | with it, each with an id greater than 0. | |
200 | ||
201 | Accesses based on one ADDRESS do not alias accesses based on other | |
202 | ADDRESSes. Accesses based on ADDRESSes in groups (2) and (3) do not | |
203 | alias globals either; the ADDRESSes have Pmode to indicate this. | |
204 | The ADDRESS in group (1) _may_ alias globals; it has VOIDmode to | |
205 | indicate this. */ | |
2a2c8203 | 206 | |
08c79682 | 207 | static GTY(()) VEC(rtx,gc) *reg_base_value; |
ac606739 | 208 | static rtx *new_reg_base_value; |
c582d54a | 209 | |
9fc37b2b RS |
210 | /* The single VOIDmode ADDRESS that represents all argument bases. |
211 | It has id 0. */ | |
212 | static GTY(()) rtx arg_base_value; | |
213 | ||
214 | /* Used to allocate unique ids to each REG_NOALIAS ADDRESS. */ | |
215 | static int unique_id; | |
216 | ||
c582d54a JH |
217 | /* We preserve the copy of old array around to avoid amount of garbage |
218 | produced. About 8% of garbage produced were attributed to this | |
219 | array. */ | |
08c79682 | 220 | static GTY((deletable)) VEC(rtx,gc) *old_reg_base_value; |
d4b60170 | 221 | |
9e412ca3 RS |
222 | /* Values of XINT (address, 0) of Pmode ADDRESS rtxes for special |
223 | registers. */ | |
224 | #define UNIQUE_BASE_VALUE_SP -1 | |
225 | #define UNIQUE_BASE_VALUE_ARGP -2 | |
226 | #define UNIQUE_BASE_VALUE_FP -3 | |
227 | #define UNIQUE_BASE_VALUE_HFP -4 | |
228 | ||
7bf84454 RS |
229 | #define static_reg_base_value \ |
230 | (this_target_rtl->x_static_reg_base_value) | |
bf1660a6 | 231 | |
08c79682 KH |
232 | #define REG_BASE_VALUE(X) \ |
233 | (REGNO (X) < VEC_length (rtx, reg_base_value) \ | |
234 | ? VEC_index (rtx, reg_base_value, REGNO (X)) : 0) | |
9ae8ffe7 | 235 | |
c13e8210 | 236 | /* Vector indexed by N giving the initial (unchanging) value known for |
9ff3c7ca | 237 | pseudo-register N. This vector is initialized in init_alias_analysis, |
bb1acb3e | 238 | and does not change until end_alias_analysis is called. */ |
9ff3c7ca | 239 | static GTY(()) VEC(rtx,gc) *reg_known_value; |
9ae8ffe7 JL |
240 | |
241 | /* Vector recording for each reg_known_value whether it is due to a | |
242 | REG_EQUIV note. Future passes (viz., reload) may replace the | |
243 | pseudo with the equivalent expression and so we account for the | |
ac3d9668 RK |
244 | dependences that would be introduced if that happens. |
245 | ||
246 | The REG_EQUIV notes created in assign_parms may mention the arg | |
247 | pointer, and there are explicit insns in the RTL that modify the | |
248 | arg pointer. Thus we must ensure that such insns don't get | |
249 | scheduled across each other because that would invalidate the | |
250 | REG_EQUIV notes. One could argue that the REG_EQUIV notes are | |
251 | wrong, but solving the problem in the scheduler will likely give | |
252 | better code, so we do it here. */ | |
9ff3c7ca | 253 | static sbitmap reg_known_equiv_p; |
9ae8ffe7 | 254 | |
2a2c8203 JC |
255 | /* True when scanning insns from the start of the rtl to the |
256 | NOTE_INSN_FUNCTION_BEG note. */ | |
83bbd9b6 | 257 | static bool copying_arguments; |
9ae8ffe7 | 258 | |
1a5640b4 KH |
259 | DEF_VEC_P(alias_set_entry); |
260 | DEF_VEC_ALLOC_P(alias_set_entry,gc); | |
261 | ||
3932261a | 262 | /* The splay-tree used to store the various alias set entries. */ |
1a5640b4 | 263 | static GTY (()) VEC(alias_set_entry,gc) *alias_sets; |
ac3d9668 | 264 | \f |
55b34b5f RG |
265 | /* Build a decomposed reference object for querying the alias-oracle |
266 | from the MEM rtx and store it in *REF. | |
267 | Returns false if MEM is not suitable for the alias-oracle. */ | |
268 | ||
269 | static bool | |
270 | ao_ref_from_mem (ao_ref *ref, const_rtx mem) | |
271 | { | |
272 | tree expr = MEM_EXPR (mem); | |
273 | tree base; | |
274 | ||
275 | if (!expr) | |
276 | return false; | |
277 | ||
278 | ao_ref_init (ref, expr); | |
279 | ||
280 | /* Get the base of the reference and see if we have to reject or | |
281 | adjust it. */ | |
282 | base = ao_ref_base (ref); | |
283 | if (base == NULL_TREE) | |
284 | return false; | |
285 | ||
366f945f RG |
286 | /* The tree oracle doesn't like to have these. */ |
287 | if (TREE_CODE (base) == FUNCTION_DECL | |
288 | || TREE_CODE (base) == LABEL_DECL) | |
289 | return false; | |
290 | ||
55b34b5f RG |
291 | /* If this is a pointer dereference of a non-SSA_NAME punt. |
292 | ??? We could replace it with a pointer to anything. */ | |
70f34814 RG |
293 | if ((INDIRECT_REF_P (base) |
294 | || TREE_CODE (base) == MEM_REF) | |
55b34b5f RG |
295 | && TREE_CODE (TREE_OPERAND (base, 0)) != SSA_NAME) |
296 | return false; | |
d15adbeb RG |
297 | if (TREE_CODE (base) == TARGET_MEM_REF |
298 | && TMR_BASE (base) | |
299 | && TREE_CODE (TMR_BASE (base)) != SSA_NAME) | |
300 | return false; | |
55b34b5f RG |
301 | |
302 | /* If this is a reference based on a partitioned decl replace the | |
303 | base with an INDIRECT_REF of the pointer representative we | |
304 | created during stack slot partitioning. */ | |
305 | if (TREE_CODE (base) == VAR_DECL | |
306 | && ! TREE_STATIC (base) | |
307 | && cfun->gimple_df->decls_to_pointers != NULL) | |
308 | { | |
309 | void *namep; | |
310 | namep = pointer_map_contains (cfun->gimple_df->decls_to_pointers, base); | |
311 | if (namep) | |
70f34814 | 312 | ref->base = build_simple_mem_ref (*(tree *)namep); |
55b34b5f | 313 | } |
d15adbeb | 314 | else if (TREE_CODE (base) == TARGET_MEM_REF |
4d948885 RG |
315 | && TREE_CODE (TMR_BASE (base)) == ADDR_EXPR |
316 | && TREE_CODE (TREE_OPERAND (TMR_BASE (base), 0)) == VAR_DECL | |
317 | && ! TREE_STATIC (TREE_OPERAND (TMR_BASE (base), 0)) | |
d15adbeb RG |
318 | && cfun->gimple_df->decls_to_pointers != NULL) |
319 | { | |
320 | void *namep; | |
321 | namep = pointer_map_contains (cfun->gimple_df->decls_to_pointers, | |
4d948885 | 322 | TREE_OPERAND (TMR_BASE (base), 0)); |
d15adbeb RG |
323 | if (namep) |
324 | ref->base = build_simple_mem_ref (*(tree *)namep); | |
325 | } | |
55b34b5f RG |
326 | |
327 | ref->ref_alias_set = MEM_ALIAS_SET (mem); | |
328 | ||
f68396a1 RG |
329 | /* If MEM_OFFSET or MEM_SIZE are unknown what we got from MEM_EXPR |
330 | is conservative, so trust it. */ | |
527210c4 | 331 | if (!MEM_OFFSET_KNOWN_P (mem) |
f5541398 | 332 | || !MEM_SIZE_KNOWN_P (mem)) |
f68396a1 | 333 | return true; |
366f945f | 334 | |
b0e96404 RG |
335 | /* If the base decl is a parameter we can have negative MEM_OFFSET in |
336 | case of promoted subregs on bigendian targets. Trust the MEM_EXPR | |
337 | here. */ | |
527210c4 RS |
338 | if (MEM_OFFSET (mem) < 0 |
339 | && (MEM_SIZE (mem) + MEM_OFFSET (mem)) * BITS_PER_UNIT == ref->size) | |
b0e96404 RG |
340 | return true; |
341 | ||
f68396a1 RG |
342 | /* Otherwise continue and refine size and offset we got from analyzing |
343 | MEM_EXPR by using MEM_SIZE and MEM_OFFSET. */ | |
344 | ||
527210c4 | 345 | ref->offset += MEM_OFFSET (mem) * BITS_PER_UNIT; |
f5541398 | 346 | ref->size = MEM_SIZE (mem) * BITS_PER_UNIT; |
b0e96404 RG |
347 | |
348 | /* The MEM may extend into adjacent fields, so adjust max_size if | |
349 | necessary. */ | |
350 | if (ref->max_size != -1 | |
351 | && ref->size > ref->max_size) | |
352 | ref->max_size = ref->size; | |
353 | ||
354 | /* If MEM_OFFSET and MEM_SIZE get us outside of the base object of | |
355 | the MEM_EXPR punt. This happens for STRICT_ALIGNMENT targets a lot. */ | |
356 | if (MEM_EXPR (mem) != get_spill_slot_decl (false) | |
357 | && (ref->offset < 0 | |
358 | || (DECL_P (ref->base) | |
359 | && (!host_integerp (DECL_SIZE (ref->base), 1) | |
360 | || (TREE_INT_CST_LOW (DECL_SIZE ((ref->base))) | |
361 | < (unsigned HOST_WIDE_INT)(ref->offset + ref->size)))))) | |
362 | return false; | |
55b34b5f RG |
363 | |
364 | return true; | |
365 | } | |
366 | ||
367 | /* Query the alias-oracle on whether the two memory rtx X and MEM may | |
368 | alias. If TBAA_P is set also apply TBAA. Returns true if the | |
369 | two rtxen may alias, false otherwise. */ | |
370 | ||
371 | static bool | |
372 | rtx_refs_may_alias_p (const_rtx x, const_rtx mem, bool tbaa_p) | |
373 | { | |
374 | ao_ref ref1, ref2; | |
375 | ||
376 | if (!ao_ref_from_mem (&ref1, x) | |
377 | || !ao_ref_from_mem (&ref2, mem)) | |
378 | return true; | |
379 | ||
55e3bc4c RG |
380 | return refs_may_alias_p_1 (&ref1, &ref2, |
381 | tbaa_p | |
382 | && MEM_ALIAS_SET (x) != 0 | |
383 | && MEM_ALIAS_SET (mem) != 0); | |
55b34b5f RG |
384 | } |
385 | ||
3932261a MM |
386 | /* Returns a pointer to the alias set entry for ALIAS_SET, if there is |
387 | such an entry, or NULL otherwise. */ | |
388 | ||
9ddb66ca | 389 | static inline alias_set_entry |
4862826d | 390 | get_alias_set_entry (alias_set_type alias_set) |
3932261a | 391 | { |
1a5640b4 | 392 | return VEC_index (alias_set_entry, alias_sets, alias_set); |
3932261a MM |
393 | } |
394 | ||
ac3d9668 RK |
395 | /* Returns nonzero if the alias sets for MEM1 and MEM2 are such that |
396 | the two MEMs cannot alias each other. */ | |
3932261a | 397 | |
9ddb66ca | 398 | static inline int |
4f588890 | 399 | mems_in_disjoint_alias_sets_p (const_rtx mem1, const_rtx mem2) |
3932261a | 400 | { |
3932261a MM |
401 | /* Perform a basic sanity check. Namely, that there are no alias sets |
402 | if we're not using strict aliasing. This helps to catch bugs | |
403 | whereby someone uses PUT_CODE, but doesn't clear MEM_ALIAS_SET, or | |
404 | where a MEM is allocated in some way other than by the use of | |
405 | gen_rtx_MEM, and the MEM_ALIAS_SET is not cleared. If we begin to | |
406 | use alias sets to indicate that spilled registers cannot alias each | |
407 | other, we might need to remove this check. */ | |
298e6adc NS |
408 | gcc_assert (flag_strict_aliasing |
409 | || (!MEM_ALIAS_SET (mem1) && !MEM_ALIAS_SET (mem2))); | |
3932261a | 410 | |
1da68f56 RK |
411 | return ! alias_sets_conflict_p (MEM_ALIAS_SET (mem1), MEM_ALIAS_SET (mem2)); |
412 | } | |
3932261a | 413 | |
1da68f56 RK |
414 | /* Insert the NODE into the splay tree given by DATA. Used by |
415 | record_alias_subset via splay_tree_foreach. */ | |
416 | ||
417 | static int | |
4682ae04 | 418 | insert_subset_children (splay_tree_node node, void *data) |
1da68f56 RK |
419 | { |
420 | splay_tree_insert ((splay_tree) data, node->key, node->value); | |
421 | ||
422 | return 0; | |
423 | } | |
424 | ||
c58936b6 DB |
425 | /* Return true if the first alias set is a subset of the second. */ |
426 | ||
427 | bool | |
4862826d | 428 | alias_set_subset_of (alias_set_type set1, alias_set_type set2) |
c58936b6 DB |
429 | { |
430 | alias_set_entry ase; | |
431 | ||
432 | /* Everything is a subset of the "aliases everything" set. */ | |
433 | if (set2 == 0) | |
434 | return true; | |
435 | ||
436 | /* Otherwise, check if set1 is a subset of set2. */ | |
437 | ase = get_alias_set_entry (set2); | |
438 | if (ase != 0 | |
038a39d1 | 439 | && (ase->has_zero_child |
a7a512be RG |
440 | || splay_tree_lookup (ase->children, |
441 | (splay_tree_key) set1))) | |
c58936b6 DB |
442 | return true; |
443 | return false; | |
444 | } | |
445 | ||
1da68f56 RK |
446 | /* Return 1 if the two specified alias sets may conflict. */ |
447 | ||
448 | int | |
4862826d | 449 | alias_sets_conflict_p (alias_set_type set1, alias_set_type set2) |
1da68f56 RK |
450 | { |
451 | alias_set_entry ase; | |
452 | ||
836f7794 EB |
453 | /* The easy case. */ |
454 | if (alias_sets_must_conflict_p (set1, set2)) | |
1da68f56 | 455 | return 1; |
3932261a | 456 | |
3bdf5ad1 | 457 | /* See if the first alias set is a subset of the second. */ |
1da68f56 | 458 | ase = get_alias_set_entry (set1); |
2bf105ab RK |
459 | if (ase != 0 |
460 | && (ase->has_zero_child | |
461 | || splay_tree_lookup (ase->children, | |
1da68f56 RK |
462 | (splay_tree_key) set2))) |
463 | return 1; | |
3932261a MM |
464 | |
465 | /* Now do the same, but with the alias sets reversed. */ | |
1da68f56 | 466 | ase = get_alias_set_entry (set2); |
2bf105ab RK |
467 | if (ase != 0 |
468 | && (ase->has_zero_child | |
469 | || splay_tree_lookup (ase->children, | |
1da68f56 RK |
470 | (splay_tree_key) set1))) |
471 | return 1; | |
3932261a | 472 | |
1da68f56 | 473 | /* The two alias sets are distinct and neither one is the |
836f7794 | 474 | child of the other. Therefore, they cannot conflict. */ |
1da68f56 | 475 | return 0; |
3932261a | 476 | } |
5399d643 | 477 | |
836f7794 | 478 | /* Return 1 if the two specified alias sets will always conflict. */ |
5399d643 JW |
479 | |
480 | int | |
4862826d | 481 | alias_sets_must_conflict_p (alias_set_type set1, alias_set_type set2) |
5399d643 JW |
482 | { |
483 | if (set1 == 0 || set2 == 0 || set1 == set2) | |
484 | return 1; | |
485 | ||
486 | return 0; | |
487 | } | |
488 | ||
1da68f56 RK |
489 | /* Return 1 if any MEM object of type T1 will always conflict (using the |
490 | dependency routines in this file) with any MEM object of type T2. | |
491 | This is used when allocating temporary storage. If T1 and/or T2 are | |
492 | NULL_TREE, it means we know nothing about the storage. */ | |
493 | ||
494 | int | |
4682ae04 | 495 | objects_must_conflict_p (tree t1, tree t2) |
1da68f56 | 496 | { |
4862826d | 497 | alias_set_type set1, set2; |
82d610ec | 498 | |
e8ea2809 RK |
499 | /* If neither has a type specified, we don't know if they'll conflict |
500 | because we may be using them to store objects of various types, for | |
501 | example the argument and local variables areas of inlined functions. */ | |
981a4c34 | 502 | if (t1 == 0 && t2 == 0) |
e8ea2809 RK |
503 | return 0; |
504 | ||
1da68f56 RK |
505 | /* If they are the same type, they must conflict. */ |
506 | if (t1 == t2 | |
507 | /* Likewise if both are volatile. */ | |
508 | || (t1 != 0 && TYPE_VOLATILE (t1) && t2 != 0 && TYPE_VOLATILE (t2))) | |
509 | return 1; | |
510 | ||
82d610ec RK |
511 | set1 = t1 ? get_alias_set (t1) : 0; |
512 | set2 = t2 ? get_alias_set (t2) : 0; | |
1da68f56 | 513 | |
836f7794 EB |
514 | /* We can't use alias_sets_conflict_p because we must make sure |
515 | that every subtype of t1 will conflict with every subtype of | |
82d610ec RK |
516 | t2 for which a pair of subobjects of these respective subtypes |
517 | overlaps on the stack. */ | |
836f7794 | 518 | return alias_sets_must_conflict_p (set1, set2); |
1da68f56 RK |
519 | } |
520 | \f | |
2039d7aa RH |
521 | /* Return true if all nested component references handled by |
522 | get_inner_reference in T are such that we should use the alias set | |
523 | provided by the object at the heart of T. | |
524 | ||
525 | This is true for non-addressable components (which don't have their | |
526 | own alias set), as well as components of objects in alias set zero. | |
527 | This later point is a special case wherein we wish to override the | |
528 | alias set used by the component, but we don't have per-FIELD_DECL | |
529 | assignable alias sets. */ | |
530 | ||
531 | bool | |
22ea9ec0 | 532 | component_uses_parent_alias_set (const_tree t) |
6e24b709 | 533 | { |
afe84921 RH |
534 | while (1) |
535 | { | |
2039d7aa | 536 | /* If we're at the end, it vacuously uses its own alias set. */ |
afe84921 | 537 | if (!handled_component_p (t)) |
2039d7aa | 538 | return false; |
afe84921 RH |
539 | |
540 | switch (TREE_CODE (t)) | |
541 | { | |
542 | case COMPONENT_REF: | |
543 | if (DECL_NONADDRESSABLE_P (TREE_OPERAND (t, 1))) | |
2039d7aa | 544 | return true; |
afe84921 RH |
545 | break; |
546 | ||
547 | case ARRAY_REF: | |
548 | case ARRAY_RANGE_REF: | |
549 | if (TYPE_NONALIASED_COMPONENT (TREE_TYPE (TREE_OPERAND (t, 0)))) | |
2039d7aa | 550 | return true; |
afe84921 RH |
551 | break; |
552 | ||
553 | case REALPART_EXPR: | |
554 | case IMAGPART_EXPR: | |
555 | break; | |
556 | ||
557 | default: | |
558 | /* Bitfields and casts are never addressable. */ | |
2039d7aa | 559 | return true; |
afe84921 RH |
560 | } |
561 | ||
562 | t = TREE_OPERAND (t, 0); | |
2039d7aa RH |
563 | if (get_alias_set (TREE_TYPE (t)) == 0) |
564 | return true; | |
afe84921 | 565 | } |
6e24b709 RK |
566 | } |
567 | ||
5006671f RG |
568 | /* Return the alias set for the memory pointed to by T, which may be |
569 | either a type or an expression. Return -1 if there is nothing | |
570 | special about dereferencing T. */ | |
571 | ||
572 | static alias_set_type | |
573 | get_deref_alias_set_1 (tree t) | |
574 | { | |
575 | /* If we're not doing any alias analysis, just assume everything | |
576 | aliases everything else. */ | |
577 | if (!flag_strict_aliasing) | |
578 | return 0; | |
579 | ||
5b21f0f3 | 580 | /* All we care about is the type. */ |
5006671f | 581 | if (! TYPE_P (t)) |
5b21f0f3 | 582 | t = TREE_TYPE (t); |
5006671f RG |
583 | |
584 | /* If we have an INDIRECT_REF via a void pointer, we don't | |
585 | know anything about what that might alias. Likewise if the | |
586 | pointer is marked that way. */ | |
587 | if (TREE_CODE (TREE_TYPE (t)) == VOID_TYPE | |
588 | || TYPE_REF_CAN_ALIAS_ALL (t)) | |
589 | return 0; | |
590 | ||
591 | return -1; | |
592 | } | |
593 | ||
594 | /* Return the alias set for the memory pointed to by T, which may be | |
595 | either a type or an expression. */ | |
596 | ||
597 | alias_set_type | |
598 | get_deref_alias_set (tree t) | |
599 | { | |
600 | alias_set_type set = get_deref_alias_set_1 (t); | |
601 | ||
602 | /* Fall back to the alias-set of the pointed-to type. */ | |
603 | if (set == -1) | |
604 | { | |
605 | if (! TYPE_P (t)) | |
606 | t = TREE_TYPE (t); | |
607 | set = get_alias_set (TREE_TYPE (t)); | |
608 | } | |
609 | ||
610 | return set; | |
611 | } | |
612 | ||
3bdf5ad1 RK |
613 | /* Return the alias set for T, which may be either a type or an |
614 | expression. Call language-specific routine for help, if needed. */ | |
615 | ||
4862826d | 616 | alias_set_type |
4682ae04 | 617 | get_alias_set (tree t) |
3bdf5ad1 | 618 | { |
4862826d | 619 | alias_set_type set; |
3bdf5ad1 RK |
620 | |
621 | /* If we're not doing any alias analysis, just assume everything | |
622 | aliases everything else. Also return 0 if this or its type is | |
623 | an error. */ | |
624 | if (! flag_strict_aliasing || t == error_mark_node | |
625 | || (! TYPE_P (t) | |
626 | && (TREE_TYPE (t) == 0 || TREE_TYPE (t) == error_mark_node))) | |
627 | return 0; | |
628 | ||
629 | /* We can be passed either an expression or a type. This and the | |
f47e9b4e RK |
630 | language-specific routine may make mutually-recursive calls to each other |
631 | to figure out what to do. At each juncture, we see if this is a tree | |
632 | that the language may need to handle specially. First handle things that | |
738cc472 | 633 | aren't types. */ |
f824e5c3 | 634 | if (! TYPE_P (t)) |
3bdf5ad1 | 635 | { |
ebcc3d93 | 636 | tree inner; |
738cc472 | 637 | |
70f34814 RG |
638 | /* Give the language a chance to do something with this tree |
639 | before we look at it. */ | |
8ac61af7 | 640 | STRIP_NOPS (t); |
ae2bcd98 | 641 | set = lang_hooks.get_alias_set (t); |
8ac61af7 RK |
642 | if (set != -1) |
643 | return set; | |
644 | ||
70f34814 | 645 | /* Get the base object of the reference. */ |
ebcc3d93 | 646 | inner = t; |
6fce44af | 647 | while (handled_component_p (inner)) |
738cc472 | 648 | { |
70f34814 RG |
649 | /* If there is a VIEW_CONVERT_EXPR in the chain we cannot use |
650 | the type of any component references that wrap it to | |
651 | determine the alias-set. */ | |
652 | if (TREE_CODE (inner) == VIEW_CONVERT_EXPR) | |
653 | t = TREE_OPERAND (inner, 0); | |
6fce44af | 654 | inner = TREE_OPERAND (inner, 0); |
738cc472 RK |
655 | } |
656 | ||
70f34814 RG |
657 | /* Handle pointer dereferences here, they can override the |
658 | alias-set. */ | |
1b096a0a | 659 | if (INDIRECT_REF_P (inner)) |
738cc472 | 660 | { |
5006671f RG |
661 | set = get_deref_alias_set_1 (TREE_OPERAND (inner, 0)); |
662 | if (set != -1) | |
663 | return set; | |
738cc472 | 664 | } |
4b228e61 RG |
665 | else if (TREE_CODE (inner) == TARGET_MEM_REF) |
666 | return get_deref_alias_set (TMR_OFFSET (inner)); | |
70f34814 RG |
667 | else if (TREE_CODE (inner) == MEM_REF) |
668 | { | |
669 | set = get_deref_alias_set_1 (TREE_OPERAND (inner, 1)); | |
670 | if (set != -1) | |
671 | return set; | |
672 | } | |
673 | ||
674 | /* If the innermost reference is a MEM_REF that has a | |
675 | conversion embedded treat it like a VIEW_CONVERT_EXPR above, | |
676 | using the memory access type for determining the alias-set. */ | |
677 | if (TREE_CODE (inner) == MEM_REF | |
7be7d292 EB |
678 | && TYPE_MAIN_VARIANT (TREE_TYPE (inner)) |
679 | != TYPE_MAIN_VARIANT | |
680 | (TREE_TYPE (TREE_TYPE (TREE_OPERAND (inner, 1))))) | |
70f34814 | 681 | return get_deref_alias_set (TREE_OPERAND (inner, 1)); |
738cc472 RK |
682 | |
683 | /* Otherwise, pick up the outermost object that we could have a pointer | |
6fce44af | 684 | to, processing conversions as above. */ |
2039d7aa | 685 | while (component_uses_parent_alias_set (t)) |
f47e9b4e | 686 | { |
6fce44af | 687 | t = TREE_OPERAND (t, 0); |
8ac61af7 RK |
688 | STRIP_NOPS (t); |
689 | } | |
f824e5c3 | 690 | |
738cc472 RK |
691 | /* If we've already determined the alias set for a decl, just return |
692 | it. This is necessary for C++ anonymous unions, whose component | |
693 | variables don't look like union members (boo!). */ | |
5755cd38 | 694 | if (TREE_CODE (t) == VAR_DECL |
3c0cb5de | 695 | && DECL_RTL_SET_P (t) && MEM_P (DECL_RTL (t))) |
5755cd38 JM |
696 | return MEM_ALIAS_SET (DECL_RTL (t)); |
697 | ||
f824e5c3 RK |
698 | /* Now all we care about is the type. */ |
699 | t = TREE_TYPE (t); | |
3bdf5ad1 RK |
700 | } |
701 | ||
3bdf5ad1 | 702 | /* Variant qualifiers don't affect the alias set, so get the main |
daad0278 | 703 | variant. */ |
3bdf5ad1 | 704 | t = TYPE_MAIN_VARIANT (t); |
daad0278 RG |
705 | |
706 | /* Always use the canonical type as well. If this is a type that | |
707 | requires structural comparisons to identify compatible types | |
708 | use alias set zero. */ | |
709 | if (TYPE_STRUCTURAL_EQUALITY_P (t)) | |
cb9c2485 JM |
710 | { |
711 | /* Allow the language to specify another alias set for this | |
712 | type. */ | |
713 | set = lang_hooks.get_alias_set (t); | |
714 | if (set != -1) | |
715 | return set; | |
716 | return 0; | |
717 | } | |
7be7d292 | 718 | |
daad0278 | 719 | t = TYPE_CANONICAL (t); |
7be7d292 | 720 | |
96d91dcf RG |
721 | /* The canonical type should not require structural equality checks. */ |
722 | gcc_checking_assert (!TYPE_STRUCTURAL_EQUALITY_P (t)); | |
daad0278 RG |
723 | |
724 | /* If this is a type with a known alias set, return it. */ | |
738cc472 | 725 | if (TYPE_ALIAS_SET_KNOWN_P (t)) |
3bdf5ad1 RK |
726 | return TYPE_ALIAS_SET (t); |
727 | ||
36784d0e RG |
728 | /* We don't want to set TYPE_ALIAS_SET for incomplete types. */ |
729 | if (!COMPLETE_TYPE_P (t)) | |
730 | { | |
731 | /* For arrays with unknown size the conservative answer is the | |
732 | alias set of the element type. */ | |
733 | if (TREE_CODE (t) == ARRAY_TYPE) | |
734 | return get_alias_set (TREE_TYPE (t)); | |
735 | ||
736 | /* But return zero as a conservative answer for incomplete types. */ | |
737 | return 0; | |
738 | } | |
739 | ||
3bdf5ad1 | 740 | /* See if the language has special handling for this type. */ |
ae2bcd98 | 741 | set = lang_hooks.get_alias_set (t); |
8ac61af7 | 742 | if (set != -1) |
738cc472 | 743 | return set; |
2bf105ab | 744 | |
3bdf5ad1 RK |
745 | /* There are no objects of FUNCTION_TYPE, so there's no point in |
746 | using up an alias set for them. (There are, of course, pointers | |
747 | and references to functions, but that's different.) */ | |
7be7d292 | 748 | else if (TREE_CODE (t) == FUNCTION_TYPE || TREE_CODE (t) == METHOD_TYPE) |
3bdf5ad1 | 749 | set = 0; |
74d86f4f RH |
750 | |
751 | /* Unless the language specifies otherwise, let vector types alias | |
752 | their components. This avoids some nasty type punning issues in | |
753 | normal usage. And indeed lets vectors be treated more like an | |
754 | array slice. */ | |
755 | else if (TREE_CODE (t) == VECTOR_TYPE) | |
756 | set = get_alias_set (TREE_TYPE (t)); | |
757 | ||
4653cae5 RG |
758 | /* Unless the language specifies otherwise, treat array types the |
759 | same as their components. This avoids the asymmetry we get | |
760 | through recording the components. Consider accessing a | |
761 | character(kind=1) through a reference to a character(kind=1)[1:1]. | |
762 | Or consider if we want to assign integer(kind=4)[0:D.1387] and | |
763 | integer(kind=4)[4] the same alias set or not. | |
764 | Just be pragmatic here and make sure the array and its element | |
765 | type get the same alias set assigned. */ | |
7be7d292 | 766 | else if (TREE_CODE (t) == ARRAY_TYPE && !TYPE_NONALIASED_COMPONENT (t)) |
4653cae5 RG |
767 | set = get_alias_set (TREE_TYPE (t)); |
768 | ||
0ceb0201 RG |
769 | /* From the former common C and C++ langhook implementation: |
770 | ||
771 | Unfortunately, there is no canonical form of a pointer type. | |
772 | In particular, if we have `typedef int I', then `int *', and | |
773 | `I *' are different types. So, we have to pick a canonical | |
774 | representative. We do this below. | |
775 | ||
776 | Technically, this approach is actually more conservative that | |
777 | it needs to be. In particular, `const int *' and `int *' | |
778 | should be in different alias sets, according to the C and C++ | |
779 | standard, since their types are not the same, and so, | |
780 | technically, an `int **' and `const int **' cannot point at | |
781 | the same thing. | |
782 | ||
783 | But, the standard is wrong. In particular, this code is | |
784 | legal C++: | |
785 | ||
786 | int *ip; | |
787 | int **ipp = &ip; | |
788 | const int* const* cipp = ipp; | |
789 | And, it doesn't make sense for that to be legal unless you | |
790 | can dereference IPP and CIPP. So, we ignore cv-qualifiers on | |
791 | the pointed-to types. This issue has been reported to the | |
792 | C++ committee. | |
793 | ||
794 | In addition to the above canonicalization issue, with LTO | |
795 | we should also canonicalize `T (*)[]' to `T *' avoiding | |
796 | alias issues with pointer-to element types and pointer-to | |
797 | array types. | |
798 | ||
799 | Likewise we need to deal with the situation of incomplete | |
800 | pointed-to types and make `*(struct X **)&a' and | |
801 | `*(struct X {} **)&a' alias. Otherwise we will have to | |
802 | guarantee that all pointer-to incomplete type variants | |
803 | will be replaced by pointer-to complete type variants if | |
804 | they are available. | |
805 | ||
806 | With LTO the convenient situation of using `void *' to | |
807 | access and store any pointer type will also become | |
808 | more apparent (and `void *' is just another pointer-to | |
809 | incomplete type). Assigning alias-set zero to `void *' | |
810 | and all pointer-to incomplete types is a not appealing | |
811 | solution. Assigning an effective alias-set zero only | |
812 | affecting pointers might be - by recording proper subset | |
813 | relationships of all pointer alias-sets. | |
814 | ||
815 | Pointer-to function types are another grey area which | |
816 | needs caution. Globbing them all into one alias-set | |
817 | or the above effective zero set would work. | |
818 | ||
819 | For now just assign the same alias-set to all pointers. | |
820 | That's simple and avoids all the above problems. */ | |
821 | else if (POINTER_TYPE_P (t) | |
822 | && t != ptr_type_node) | |
96d91dcf | 823 | set = get_alias_set (ptr_type_node); |
0ceb0201 | 824 | |
7be7d292 | 825 | /* Otherwise make a new alias set for this type. */ |
3bdf5ad1 | 826 | else |
96d91dcf RG |
827 | { |
828 | /* Each canonical type gets its own alias set, so canonical types | |
829 | shouldn't form a tree. It doesn't really matter for types | |
830 | we handle specially above, so only check it where it possibly | |
831 | would result in a bogus alias set. */ | |
832 | gcc_checking_assert (TYPE_CANONICAL (t) == t); | |
833 | ||
834 | set = new_alias_set (); | |
835 | } | |
3bdf5ad1 RK |
836 | |
837 | TYPE_ALIAS_SET (t) = set; | |
2bf105ab | 838 | |
7be7d292 EB |
839 | /* If this is an aggregate type or a complex type, we must record any |
840 | component aliasing information. */ | |
1d79fd2c | 841 | if (AGGREGATE_TYPE_P (t) || TREE_CODE (t) == COMPLEX_TYPE) |
2bf105ab RK |
842 | record_component_aliases (t); |
843 | ||
3bdf5ad1 RK |
844 | return set; |
845 | } | |
846 | ||
847 | /* Return a brand-new alias set. */ | |
848 | ||
4862826d | 849 | alias_set_type |
4682ae04 | 850 | new_alias_set (void) |
3bdf5ad1 | 851 | { |
3bdf5ad1 | 852 | if (flag_strict_aliasing) |
9ddb66ca | 853 | { |
1a5640b4 | 854 | if (alias_sets == 0) |
0823efed DN |
855 | VEC_safe_push (alias_set_entry, gc, alias_sets, (alias_set_entry) 0); |
856 | VEC_safe_push (alias_set_entry, gc, alias_sets, (alias_set_entry) 0); | |
1a5640b4 | 857 | return VEC_length (alias_set_entry, alias_sets) - 1; |
9ddb66ca | 858 | } |
3bdf5ad1 RK |
859 | else |
860 | return 0; | |
861 | } | |
3932261a | 862 | |
01d28c3f JM |
863 | /* Indicate that things in SUBSET can alias things in SUPERSET, but that |
864 | not everything that aliases SUPERSET also aliases SUBSET. For example, | |
865 | in C, a store to an `int' can alias a load of a structure containing an | |
866 | `int', and vice versa. But it can't alias a load of a 'double' member | |
867 | of the same structure. Here, the structure would be the SUPERSET and | |
868 | `int' the SUBSET. This relationship is also described in the comment at | |
869 | the beginning of this file. | |
870 | ||
871 | This function should be called only once per SUPERSET/SUBSET pair. | |
3932261a MM |
872 | |
873 | It is illegal for SUPERSET to be zero; everything is implicitly a | |
874 | subset of alias set zero. */ | |
875 | ||
794511d2 | 876 | void |
4862826d | 877 | record_alias_subset (alias_set_type superset, alias_set_type subset) |
3932261a MM |
878 | { |
879 | alias_set_entry superset_entry; | |
880 | alias_set_entry subset_entry; | |
881 | ||
f47e9b4e RK |
882 | /* It is possible in complex type situations for both sets to be the same, |
883 | in which case we can ignore this operation. */ | |
884 | if (superset == subset) | |
885 | return; | |
886 | ||
298e6adc | 887 | gcc_assert (superset); |
3932261a MM |
888 | |
889 | superset_entry = get_alias_set_entry (superset); | |
ca7fd9cd | 890 | if (superset_entry == 0) |
3932261a MM |
891 | { |
892 | /* Create an entry for the SUPERSET, so that we have a place to | |
893 | attach the SUBSET. */ | |
a9429e29 | 894 | superset_entry = ggc_alloc_cleared_alias_set_entry_d (); |
3932261a | 895 | superset_entry->alias_set = superset; |
ca7fd9cd | 896 | superset_entry->children |
a9429e29 LB |
897 | = splay_tree_new_ggc (splay_tree_compare_ints, |
898 | ggc_alloc_splay_tree_scalar_scalar_splay_tree_s, | |
899 | ggc_alloc_splay_tree_scalar_scalar_splay_tree_node_s); | |
570eb5c8 | 900 | superset_entry->has_zero_child = 0; |
1a5640b4 | 901 | VEC_replace (alias_set_entry, alias_sets, superset, superset_entry); |
3932261a MM |
902 | } |
903 | ||
2bf105ab RK |
904 | if (subset == 0) |
905 | superset_entry->has_zero_child = 1; | |
906 | else | |
907 | { | |
908 | subset_entry = get_alias_set_entry (subset); | |
909 | /* If there is an entry for the subset, enter all of its children | |
910 | (if they are not already present) as children of the SUPERSET. */ | |
ca7fd9cd | 911 | if (subset_entry) |
2bf105ab RK |
912 | { |
913 | if (subset_entry->has_zero_child) | |
914 | superset_entry->has_zero_child = 1; | |
d4b60170 | 915 | |
2bf105ab RK |
916 | splay_tree_foreach (subset_entry->children, insert_subset_children, |
917 | superset_entry->children); | |
918 | } | |
3932261a | 919 | |
2bf105ab | 920 | /* Enter the SUBSET itself as a child of the SUPERSET. */ |
ca7fd9cd | 921 | splay_tree_insert (superset_entry->children, |
2bf105ab RK |
922 | (splay_tree_key) subset, 0); |
923 | } | |
3932261a MM |
924 | } |
925 | ||
a0c33338 RK |
926 | /* Record that component types of TYPE, if any, are part of that type for |
927 | aliasing purposes. For record types, we only record component types | |
b5487346 EB |
928 | for fields that are not marked non-addressable. For array types, we |
929 | only record the component type if it is not marked non-aliased. */ | |
a0c33338 RK |
930 | |
931 | void | |
4682ae04 | 932 | record_component_aliases (tree type) |
a0c33338 | 933 | { |
4862826d | 934 | alias_set_type superset = get_alias_set (type); |
a0c33338 RK |
935 | tree field; |
936 | ||
937 | if (superset == 0) | |
938 | return; | |
939 | ||
940 | switch (TREE_CODE (type)) | |
941 | { | |
a0c33338 RK |
942 | case RECORD_TYPE: |
943 | case UNION_TYPE: | |
944 | case QUAL_UNION_TYPE: | |
6614fd40 | 945 | /* Recursively record aliases for the base classes, if there are any. */ |
fa743e8c | 946 | if (TYPE_BINFO (type)) |
ca7fd9cd KH |
947 | { |
948 | int i; | |
fa743e8c | 949 | tree binfo, base_binfo; |
c22cacf3 | 950 | |
fa743e8c NS |
951 | for (binfo = TYPE_BINFO (type), i = 0; |
952 | BINFO_BASE_ITERATE (binfo, i, base_binfo); i++) | |
953 | record_alias_subset (superset, | |
954 | get_alias_set (BINFO_TYPE (base_binfo))); | |
ca7fd9cd | 955 | } |
910ad8de | 956 | for (field = TYPE_FIELDS (type); field != 0; field = DECL_CHAIN (field)) |
b5487346 | 957 | if (TREE_CODE (field) == FIELD_DECL && !DECL_NONADDRESSABLE_P (field)) |
2bf105ab | 958 | record_alias_subset (superset, get_alias_set (TREE_TYPE (field))); |
a0c33338 RK |
959 | break; |
960 | ||
1d79fd2c JW |
961 | case COMPLEX_TYPE: |
962 | record_alias_subset (superset, get_alias_set (TREE_TYPE (type))); | |
963 | break; | |
964 | ||
4653cae5 RG |
965 | /* VECTOR_TYPE and ARRAY_TYPE share the alias set with their |
966 | element type. */ | |
967 | ||
a0c33338 RK |
968 | default: |
969 | break; | |
970 | } | |
971 | } | |
972 | ||
3bdf5ad1 RK |
973 | /* Allocate an alias set for use in storing and reading from the varargs |
974 | spill area. */ | |
975 | ||
4862826d | 976 | static GTY(()) alias_set_type varargs_set = -1; |
f103e34d | 977 | |
4862826d | 978 | alias_set_type |
4682ae04 | 979 | get_varargs_alias_set (void) |
3bdf5ad1 | 980 | { |
cd3ce9b4 JM |
981 | #if 1 |
982 | /* We now lower VA_ARG_EXPR, and there's currently no way to attach the | |
983 | varargs alias set to an INDIRECT_REF (FIXME!), so we can't | |
984 | consistently use the varargs alias set for loads from the varargs | |
985 | area. So don't use it anywhere. */ | |
986 | return 0; | |
987 | #else | |
f103e34d GK |
988 | if (varargs_set == -1) |
989 | varargs_set = new_alias_set (); | |
3bdf5ad1 | 990 | |
f103e34d | 991 | return varargs_set; |
cd3ce9b4 | 992 | #endif |
3bdf5ad1 RK |
993 | } |
994 | ||
995 | /* Likewise, but used for the fixed portions of the frame, e.g., register | |
996 | save areas. */ | |
997 | ||
4862826d | 998 | static GTY(()) alias_set_type frame_set = -1; |
f103e34d | 999 | |
4862826d | 1000 | alias_set_type |
4682ae04 | 1001 | get_frame_alias_set (void) |
3bdf5ad1 | 1002 | { |
f103e34d GK |
1003 | if (frame_set == -1) |
1004 | frame_set = new_alias_set (); | |
3bdf5ad1 | 1005 | |
f103e34d | 1006 | return frame_set; |
3bdf5ad1 RK |
1007 | } |
1008 | ||
9fc37b2b RS |
1009 | /* Create a new, unique base with id ID. */ |
1010 | ||
1011 | static rtx | |
1012 | unique_base_value (HOST_WIDE_INT id) | |
1013 | { | |
1014 | return gen_rtx_ADDRESS (Pmode, id); | |
1015 | } | |
1016 | ||
1017 | /* Return true if accesses based on any other base value cannot alias | |
1018 | those based on X. */ | |
1019 | ||
1020 | static bool | |
1021 | unique_base_value_p (rtx x) | |
1022 | { | |
1023 | return GET_CODE (x) == ADDRESS && GET_MODE (x) == Pmode; | |
1024 | } | |
1025 | ||
1026 | /* Return true if X is known to be a base value. */ | |
1027 | ||
1028 | static bool | |
1029 | known_base_value_p (rtx x) | |
1030 | { | |
1031 | switch (GET_CODE (x)) | |
1032 | { | |
1033 | case LABEL_REF: | |
1034 | case SYMBOL_REF: | |
1035 | return true; | |
1036 | ||
1037 | case ADDRESS: | |
1038 | /* Arguments may or may not be bases; we don't know for sure. */ | |
1039 | return GET_MODE (x) != VOIDmode; | |
1040 | ||
1041 | default: | |
1042 | return false; | |
1043 | } | |
1044 | } | |
1045 | ||
2a2c8203 JC |
1046 | /* Inside SRC, the source of a SET, find a base address. */ |
1047 | ||
9ae8ffe7 | 1048 | static rtx |
4682ae04 | 1049 | find_base_value (rtx src) |
9ae8ffe7 | 1050 | { |
713f41f9 | 1051 | unsigned int regno; |
0aacc8ed | 1052 | |
53451050 RS |
1053 | #if defined (FIND_BASE_TERM) |
1054 | /* Try machine-dependent ways to find the base term. */ | |
1055 | src = FIND_BASE_TERM (src); | |
1056 | #endif | |
1057 | ||
9ae8ffe7 JL |
1058 | switch (GET_CODE (src)) |
1059 | { | |
1060 | case SYMBOL_REF: | |
1061 | case LABEL_REF: | |
1062 | return src; | |
1063 | ||
1064 | case REG: | |
fb6754f0 | 1065 | regno = REGNO (src); |
d4b60170 | 1066 | /* At the start of a function, argument registers have known base |
2a2c8203 JC |
1067 | values which may be lost later. Returning an ADDRESS |
1068 | expression here allows optimization based on argument values | |
1069 | even when the argument registers are used for other purposes. */ | |
713f41f9 BS |
1070 | if (regno < FIRST_PSEUDO_REGISTER && copying_arguments) |
1071 | return new_reg_base_value[regno]; | |
73774bc7 | 1072 | |
eaf407a5 | 1073 | /* If a pseudo has a known base value, return it. Do not do this |
9b462c42 RH |
1074 | for non-fixed hard regs since it can result in a circular |
1075 | dependency chain for registers which have values at function entry. | |
eaf407a5 JL |
1076 | |
1077 | The test above is not sufficient because the scheduler may move | |
1078 | a copy out of an arg reg past the NOTE_INSN_FUNCTION_BEGIN. */ | |
9b462c42 | 1079 | if ((regno >= FIRST_PSEUDO_REGISTER || fixed_regs[regno]) |
08c79682 | 1080 | && regno < VEC_length (rtx, reg_base_value)) |
83bbd9b6 RH |
1081 | { |
1082 | /* If we're inside init_alias_analysis, use new_reg_base_value | |
1083 | to reduce the number of relaxation iterations. */ | |
1afdf91c | 1084 | if (new_reg_base_value && new_reg_base_value[regno] |
6fb5fa3c | 1085 | && DF_REG_DEF_COUNT (regno) == 1) |
83bbd9b6 RH |
1086 | return new_reg_base_value[regno]; |
1087 | ||
08c79682 KH |
1088 | if (VEC_index (rtx, reg_base_value, regno)) |
1089 | return VEC_index (rtx, reg_base_value, regno); | |
83bbd9b6 | 1090 | } |
73774bc7 | 1091 | |
e3f049a8 | 1092 | return 0; |
9ae8ffe7 JL |
1093 | |
1094 | case MEM: | |
1095 | /* Check for an argument passed in memory. Only record in the | |
1096 | copying-arguments block; it is too hard to track changes | |
1097 | otherwise. */ | |
1098 | if (copying_arguments | |
1099 | && (XEXP (src, 0) == arg_pointer_rtx | |
1100 | || (GET_CODE (XEXP (src, 0)) == PLUS | |
1101 | && XEXP (XEXP (src, 0), 0) == arg_pointer_rtx))) | |
9fc37b2b | 1102 | return arg_base_value; |
9ae8ffe7 JL |
1103 | return 0; |
1104 | ||
1105 | case CONST: | |
1106 | src = XEXP (src, 0); | |
1107 | if (GET_CODE (src) != PLUS && GET_CODE (src) != MINUS) | |
1108 | break; | |
d4b60170 | 1109 | |
ec5c56db | 1110 | /* ... fall through ... */ |
2a2c8203 | 1111 | |
9ae8ffe7 JL |
1112 | case PLUS: |
1113 | case MINUS: | |
2a2c8203 | 1114 | { |
ec907dd8 JL |
1115 | rtx temp, src_0 = XEXP (src, 0), src_1 = XEXP (src, 1); |
1116 | ||
0134bf2d DE |
1117 | /* If either operand is a REG that is a known pointer, then it |
1118 | is the base. */ | |
1119 | if (REG_P (src_0) && REG_POINTER (src_0)) | |
1120 | return find_base_value (src_0); | |
1121 | if (REG_P (src_1) && REG_POINTER (src_1)) | |
1122 | return find_base_value (src_1); | |
1123 | ||
ec907dd8 JL |
1124 | /* If either operand is a REG, then see if we already have |
1125 | a known value for it. */ | |
0134bf2d | 1126 | if (REG_P (src_0)) |
ec907dd8 JL |
1127 | { |
1128 | temp = find_base_value (src_0); | |
d4b60170 | 1129 | if (temp != 0) |
ec907dd8 JL |
1130 | src_0 = temp; |
1131 | } | |
1132 | ||
0134bf2d | 1133 | if (REG_P (src_1)) |
ec907dd8 JL |
1134 | { |
1135 | temp = find_base_value (src_1); | |
d4b60170 | 1136 | if (temp!= 0) |
ec907dd8 JL |
1137 | src_1 = temp; |
1138 | } | |
2a2c8203 | 1139 | |
0134bf2d DE |
1140 | /* If either base is named object or a special address |
1141 | (like an argument or stack reference), then use it for the | |
1142 | base term. */ | |
9fc37b2b | 1143 | if (src_0 != 0 && known_base_value_p (src_0)) |
0134bf2d DE |
1144 | return src_0; |
1145 | ||
9fc37b2b | 1146 | if (src_1 != 0 && known_base_value_p (src_1)) |
0134bf2d DE |
1147 | return src_1; |
1148 | ||
d4b60170 | 1149 | /* Guess which operand is the base address: |
ec907dd8 JL |
1150 | If either operand is a symbol, then it is the base. If |
1151 | either operand is a CONST_INT, then the other is the base. */ | |
481683e1 | 1152 | if (CONST_INT_P (src_1) || CONSTANT_P (src_0)) |
2a2c8203 | 1153 | return find_base_value (src_0); |
481683e1 | 1154 | else if (CONST_INT_P (src_0) || CONSTANT_P (src_1)) |
ec907dd8 JL |
1155 | return find_base_value (src_1); |
1156 | ||
9ae8ffe7 | 1157 | return 0; |
2a2c8203 JC |
1158 | } |
1159 | ||
1160 | case LO_SUM: | |
1161 | /* The standard form is (lo_sum reg sym) so look only at the | |
1162 | second operand. */ | |
1163 | return find_base_value (XEXP (src, 1)); | |
9ae8ffe7 JL |
1164 | |
1165 | case AND: | |
1166 | /* If the second operand is constant set the base | |
ec5c56db | 1167 | address to the first operand. */ |
481683e1 | 1168 | if (CONST_INT_P (XEXP (src, 1)) && INTVAL (XEXP (src, 1)) != 0) |
2a2c8203 | 1169 | return find_base_value (XEXP (src, 0)); |
9ae8ffe7 JL |
1170 | return 0; |
1171 | ||
61f0131c | 1172 | case TRUNCATE: |
5932a4d4 | 1173 | /* As we do not know which address space the pointer is referring to, we can |
d4ebfa65 BE |
1174 | handle this only if the target does not support different pointer or |
1175 | address modes depending on the address space. */ | |
1176 | if (!target_default_pointer_address_modes_p ()) | |
1177 | break; | |
61f0131c R |
1178 | if (GET_MODE_SIZE (GET_MODE (src)) < GET_MODE_SIZE (Pmode)) |
1179 | break; | |
1180 | /* Fall through. */ | |
9ae8ffe7 | 1181 | case HIGH: |
d288e53d DE |
1182 | case PRE_INC: |
1183 | case PRE_DEC: | |
1184 | case POST_INC: | |
1185 | case POST_DEC: | |
1186 | case PRE_MODIFY: | |
1187 | case POST_MODIFY: | |
2a2c8203 | 1188 | return find_base_value (XEXP (src, 0)); |
1d300e19 | 1189 | |
0aacc8ed RK |
1190 | case ZERO_EXTEND: |
1191 | case SIGN_EXTEND: /* used for NT/Alpha pointers */ | |
5932a4d4 | 1192 | /* As we do not know which address space the pointer is referring to, we can |
d4ebfa65 BE |
1193 | handle this only if the target does not support different pointer or |
1194 | address modes depending on the address space. */ | |
1195 | if (!target_default_pointer_address_modes_p ()) | |
1196 | break; | |
1197 | ||
0aacc8ed RK |
1198 | { |
1199 | rtx temp = find_base_value (XEXP (src, 0)); | |
1200 | ||
5ae6cd0d | 1201 | if (temp != 0 && CONSTANT_P (temp)) |
0aacc8ed | 1202 | temp = convert_memory_address (Pmode, temp); |
0aacc8ed RK |
1203 | |
1204 | return temp; | |
1205 | } | |
1206 | ||
1d300e19 KG |
1207 | default: |
1208 | break; | |
9ae8ffe7 JL |
1209 | } |
1210 | ||
1211 | return 0; | |
1212 | } | |
1213 | ||
9fc37b2b RS |
1214 | /* Called from init_alias_analysis indirectly through note_stores, |
1215 | or directly if DEST is a register with a REG_NOALIAS note attached. | |
1216 | SET is null in the latter case. */ | |
9ae8ffe7 | 1217 | |
d4b60170 | 1218 | /* While scanning insns to find base values, reg_seen[N] is nonzero if |
9ae8ffe7 JL |
1219 | register N has been set in this function. */ |
1220 | static char *reg_seen; | |
1221 | ||
2a2c8203 | 1222 | static void |
7bc980e1 | 1223 | record_set (rtx dest, const_rtx set, void *data ATTRIBUTE_UNUSED) |
9ae8ffe7 | 1224 | { |
b3694847 | 1225 | unsigned regno; |
9ae8ffe7 | 1226 | rtx src; |
c28b4e40 | 1227 | int n; |
9ae8ffe7 | 1228 | |
f8cfc6aa | 1229 | if (!REG_P (dest)) |
9ae8ffe7 JL |
1230 | return; |
1231 | ||
fb6754f0 | 1232 | regno = REGNO (dest); |
9ae8ffe7 | 1233 | |
7a40b8b1 | 1234 | gcc_checking_assert (regno < VEC_length (rtx, reg_base_value)); |
ac606739 | 1235 | |
c28b4e40 JW |
1236 | /* If this spans multiple hard registers, then we must indicate that every |
1237 | register has an unusable value. */ | |
1238 | if (regno < FIRST_PSEUDO_REGISTER) | |
66fd46b6 | 1239 | n = hard_regno_nregs[regno][GET_MODE (dest)]; |
c28b4e40 JW |
1240 | else |
1241 | n = 1; | |
1242 | if (n != 1) | |
1243 | { | |
1244 | while (--n >= 0) | |
1245 | { | |
1246 | reg_seen[regno + n] = 1; | |
1247 | new_reg_base_value[regno + n] = 0; | |
1248 | } | |
1249 | return; | |
1250 | } | |
1251 | ||
9ae8ffe7 JL |
1252 | if (set) |
1253 | { | |
1254 | /* A CLOBBER wipes out any old value but does not prevent a previously | |
1255 | unset register from acquiring a base address (i.e. reg_seen is not | |
1256 | set). */ | |
1257 | if (GET_CODE (set) == CLOBBER) | |
1258 | { | |
ec907dd8 | 1259 | new_reg_base_value[regno] = 0; |
9ae8ffe7 JL |
1260 | return; |
1261 | } | |
1262 | src = SET_SRC (set); | |
1263 | } | |
1264 | else | |
1265 | { | |
9fc37b2b | 1266 | /* There's a REG_NOALIAS note against DEST. */ |
9ae8ffe7 JL |
1267 | if (reg_seen[regno]) |
1268 | { | |
ec907dd8 | 1269 | new_reg_base_value[regno] = 0; |
9ae8ffe7 JL |
1270 | return; |
1271 | } | |
1272 | reg_seen[regno] = 1; | |
9fc37b2b | 1273 | new_reg_base_value[regno] = unique_base_value (unique_id++); |
9ae8ffe7 JL |
1274 | return; |
1275 | } | |
1276 | ||
5da6f168 RS |
1277 | /* If this is not the first set of REGNO, see whether the new value |
1278 | is related to the old one. There are two cases of interest: | |
1279 | ||
1280 | (1) The register might be assigned an entirely new value | |
1281 | that has the same base term as the original set. | |
1282 | ||
1283 | (2) The set might be a simple self-modification that | |
1284 | cannot change REGNO's base value. | |
1285 | ||
1286 | If neither case holds, reject the original base value as invalid. | |
1287 | Note that the following situation is not detected: | |
1288 | ||
c22cacf3 | 1289 | extern int x, y; int *p = &x; p += (&y-&x); |
5da6f168 | 1290 | |
9ae8ffe7 JL |
1291 | ANSI C does not allow computing the difference of addresses |
1292 | of distinct top level objects. */ | |
5da6f168 RS |
1293 | if (new_reg_base_value[regno] != 0 |
1294 | && find_base_value (src) != new_reg_base_value[regno]) | |
9ae8ffe7 JL |
1295 | switch (GET_CODE (src)) |
1296 | { | |
2a2c8203 | 1297 | case LO_SUM: |
9ae8ffe7 JL |
1298 | case MINUS: |
1299 | if (XEXP (src, 0) != dest && XEXP (src, 1) != dest) | |
ec907dd8 | 1300 | new_reg_base_value[regno] = 0; |
9ae8ffe7 | 1301 | break; |
61f0131c R |
1302 | case PLUS: |
1303 | /* If the value we add in the PLUS is also a valid base value, | |
1304 | this might be the actual base value, and the original value | |
1305 | an index. */ | |
1306 | { | |
1307 | rtx other = NULL_RTX; | |
1308 | ||
1309 | if (XEXP (src, 0) == dest) | |
1310 | other = XEXP (src, 1); | |
1311 | else if (XEXP (src, 1) == dest) | |
1312 | other = XEXP (src, 0); | |
1313 | ||
1314 | if (! other || find_base_value (other)) | |
1315 | new_reg_base_value[regno] = 0; | |
1316 | break; | |
1317 | } | |
9ae8ffe7 | 1318 | case AND: |
481683e1 | 1319 | if (XEXP (src, 0) != dest || !CONST_INT_P (XEXP (src, 1))) |
ec907dd8 | 1320 | new_reg_base_value[regno] = 0; |
9ae8ffe7 | 1321 | break; |
9ae8ffe7 | 1322 | default: |
ec907dd8 | 1323 | new_reg_base_value[regno] = 0; |
9ae8ffe7 JL |
1324 | break; |
1325 | } | |
1326 | /* If this is the first set of a register, record the value. */ | |
1327 | else if ((regno >= FIRST_PSEUDO_REGISTER || ! fixed_regs[regno]) | |
ec907dd8 JL |
1328 | && ! reg_seen[regno] && new_reg_base_value[regno] == 0) |
1329 | new_reg_base_value[regno] = find_base_value (src); | |
9ae8ffe7 JL |
1330 | |
1331 | reg_seen[regno] = 1; | |
1332 | } | |
1333 | ||
8fd0a474 AM |
1334 | /* Return REG_BASE_VALUE for REGNO. Selective scheduler uses this to avoid |
1335 | using hard registers with non-null REG_BASE_VALUE for renaming. */ | |
1336 | rtx | |
1337 | get_reg_base_value (unsigned int regno) | |
1338 | { | |
1339 | return VEC_index (rtx, reg_base_value, regno); | |
1340 | } | |
1341 | ||
bb1acb3e RH |
1342 | /* If a value is known for REGNO, return it. */ |
1343 | ||
c22cacf3 | 1344 | rtx |
bb1acb3e RH |
1345 | get_reg_known_value (unsigned int regno) |
1346 | { | |
1347 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1348 | { | |
1349 | regno -= FIRST_PSEUDO_REGISTER; | |
9ff3c7ca SB |
1350 | if (regno < VEC_length (rtx, reg_known_value)) |
1351 | return VEC_index (rtx, reg_known_value, regno); | |
bb1acb3e RH |
1352 | } |
1353 | return NULL; | |
43fe47ca JW |
1354 | } |
1355 | ||
bb1acb3e RH |
1356 | /* Set it. */ |
1357 | ||
1358 | static void | |
1359 | set_reg_known_value (unsigned int regno, rtx val) | |
1360 | { | |
1361 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1362 | { | |
1363 | regno -= FIRST_PSEUDO_REGISTER; | |
9ff3c7ca SB |
1364 | if (regno < VEC_length (rtx, reg_known_value)) |
1365 | VEC_replace (rtx, reg_known_value, regno, val); | |
bb1acb3e RH |
1366 | } |
1367 | } | |
1368 | ||
1369 | /* Similarly for reg_known_equiv_p. */ | |
1370 | ||
1371 | bool | |
1372 | get_reg_known_equiv_p (unsigned int regno) | |
1373 | { | |
1374 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1375 | { | |
1376 | regno -= FIRST_PSEUDO_REGISTER; | |
9ff3c7ca SB |
1377 | if (regno < VEC_length (rtx, reg_known_value)) |
1378 | return TEST_BIT (reg_known_equiv_p, regno); | |
bb1acb3e RH |
1379 | } |
1380 | return false; | |
1381 | } | |
1382 | ||
1383 | static void | |
1384 | set_reg_known_equiv_p (unsigned int regno, bool val) | |
1385 | { | |
1386 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1387 | { | |
1388 | regno -= FIRST_PSEUDO_REGISTER; | |
9ff3c7ca SB |
1389 | if (regno < VEC_length (rtx, reg_known_value)) |
1390 | { | |
1391 | if (val) | |
1392 | SET_BIT (reg_known_equiv_p, regno); | |
1393 | else | |
1394 | RESET_BIT (reg_known_equiv_p, regno); | |
1395 | } | |
bb1acb3e RH |
1396 | } |
1397 | } | |
1398 | ||
1399 | ||
db048faf MM |
1400 | /* Returns a canonical version of X, from the point of view alias |
1401 | analysis. (For example, if X is a MEM whose address is a register, | |
1402 | and the register has a known value (say a SYMBOL_REF), then a MEM | |
1403 | whose address is the SYMBOL_REF is returned.) */ | |
1404 | ||
1405 | rtx | |
4682ae04 | 1406 | canon_rtx (rtx x) |
9ae8ffe7 JL |
1407 | { |
1408 | /* Recursively look for equivalences. */ | |
f8cfc6aa | 1409 | if (REG_P (x) && REGNO (x) >= FIRST_PSEUDO_REGISTER) |
bb1acb3e RH |
1410 | { |
1411 | rtx t = get_reg_known_value (REGNO (x)); | |
1412 | if (t == x) | |
1413 | return x; | |
1414 | if (t) | |
1415 | return canon_rtx (t); | |
1416 | } | |
1417 | ||
1418 | if (GET_CODE (x) == PLUS) | |
9ae8ffe7 JL |
1419 | { |
1420 | rtx x0 = canon_rtx (XEXP (x, 0)); | |
1421 | rtx x1 = canon_rtx (XEXP (x, 1)); | |
1422 | ||
1423 | if (x0 != XEXP (x, 0) || x1 != XEXP (x, 1)) | |
1424 | { | |
481683e1 | 1425 | if (CONST_INT_P (x0)) |
0a81f074 | 1426 | return plus_constant (GET_MODE (x), x1, INTVAL (x0)); |
481683e1 | 1427 | else if (CONST_INT_P (x1)) |
0a81f074 | 1428 | return plus_constant (GET_MODE (x), x0, INTVAL (x1)); |
38a448ca | 1429 | return gen_rtx_PLUS (GET_MODE (x), x0, x1); |
9ae8ffe7 JL |
1430 | } |
1431 | } | |
d4b60170 | 1432 | |
9ae8ffe7 JL |
1433 | /* This gives us much better alias analysis when called from |
1434 | the loop optimizer. Note we want to leave the original | |
1435 | MEM alone, but need to return the canonicalized MEM with | |
1436 | all the flags with their original values. */ | |
3c0cb5de | 1437 | else if (MEM_P (x)) |
f1ec5147 | 1438 | x = replace_equiv_address_nv (x, canon_rtx (XEXP (x, 0))); |
d4b60170 | 1439 | |
9ae8ffe7 JL |
1440 | return x; |
1441 | } | |
1442 | ||
1443 | /* Return 1 if X and Y are identical-looking rtx's. | |
45183e03 | 1444 | Expect that X and Y has been already canonicalized. |
9ae8ffe7 JL |
1445 | |
1446 | We use the data in reg_known_value above to see if two registers with | |
1447 | different numbers are, in fact, equivalent. */ | |
1448 | ||
1449 | static int | |
ed7a4b4b | 1450 | rtx_equal_for_memref_p (const_rtx x, const_rtx y) |
9ae8ffe7 | 1451 | { |
b3694847 SS |
1452 | int i; |
1453 | int j; | |
1454 | enum rtx_code code; | |
1455 | const char *fmt; | |
9ae8ffe7 JL |
1456 | |
1457 | if (x == 0 && y == 0) | |
1458 | return 1; | |
1459 | if (x == 0 || y == 0) | |
1460 | return 0; | |
d4b60170 | 1461 | |
9ae8ffe7 JL |
1462 | if (x == y) |
1463 | return 1; | |
1464 | ||
1465 | code = GET_CODE (x); | |
1466 | /* Rtx's of different codes cannot be equal. */ | |
1467 | if (code != GET_CODE (y)) | |
1468 | return 0; | |
1469 | ||
1470 | /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. | |
1471 | (REG:SI x) and (REG:HI x) are NOT equivalent. */ | |
1472 | ||
1473 | if (GET_MODE (x) != GET_MODE (y)) | |
1474 | return 0; | |
1475 | ||
db048faf MM |
1476 | /* Some RTL can be compared without a recursive examination. */ |
1477 | switch (code) | |
1478 | { | |
1479 | case REG: | |
1480 | return REGNO (x) == REGNO (y); | |
1481 | ||
1482 | case LABEL_REF: | |
1483 | return XEXP (x, 0) == XEXP (y, 0); | |
ca7fd9cd | 1484 | |
db048faf MM |
1485 | case SYMBOL_REF: |
1486 | return XSTR (x, 0) == XSTR (y, 0); | |
1487 | ||
40e02b4a | 1488 | case VALUE: |
db048faf MM |
1489 | case CONST_INT: |
1490 | case CONST_DOUBLE: | |
091a3ac7 | 1491 | case CONST_FIXED: |
db048faf MM |
1492 | /* There's no need to compare the contents of CONST_DOUBLEs or |
1493 | CONST_INTs because pointer equality is a good enough | |
1494 | comparison for these nodes. */ | |
1495 | return 0; | |
1496 | ||
db048faf MM |
1497 | default: |
1498 | break; | |
1499 | } | |
9ae8ffe7 | 1500 | |
45183e03 JH |
1501 | /* canon_rtx knows how to handle plus. No need to canonicalize. */ |
1502 | if (code == PLUS) | |
9ae8ffe7 JL |
1503 | return ((rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 0)) |
1504 | && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 1))) | |
1505 | || (rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 1)) | |
1506 | && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 0)))); | |
45183e03 JH |
1507 | /* For commutative operations, the RTX match if the operand match in any |
1508 | order. Also handle the simple binary and unary cases without a loop. */ | |
ec8e098d | 1509 | if (COMMUTATIVE_P (x)) |
45183e03 JH |
1510 | { |
1511 | rtx xop0 = canon_rtx (XEXP (x, 0)); | |
1512 | rtx yop0 = canon_rtx (XEXP (y, 0)); | |
1513 | rtx yop1 = canon_rtx (XEXP (y, 1)); | |
1514 | ||
1515 | return ((rtx_equal_for_memref_p (xop0, yop0) | |
1516 | && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), yop1)) | |
1517 | || (rtx_equal_for_memref_p (xop0, yop1) | |
1518 | && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), yop0))); | |
1519 | } | |
ec8e098d | 1520 | else if (NON_COMMUTATIVE_P (x)) |
45183e03 JH |
1521 | { |
1522 | return (rtx_equal_for_memref_p (canon_rtx (XEXP (x, 0)), | |
4682ae04 | 1523 | canon_rtx (XEXP (y, 0))) |
45183e03 JH |
1524 | && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), |
1525 | canon_rtx (XEXP (y, 1)))); | |
1526 | } | |
ec8e098d | 1527 | else if (UNARY_P (x)) |
45183e03 | 1528 | return rtx_equal_for_memref_p (canon_rtx (XEXP (x, 0)), |
4682ae04 | 1529 | canon_rtx (XEXP (y, 0))); |
9ae8ffe7 JL |
1530 | |
1531 | /* Compare the elements. If any pair of corresponding elements | |
de12be17 JC |
1532 | fail to match, return 0 for the whole things. |
1533 | ||
1534 | Limit cases to types which actually appear in addresses. */ | |
9ae8ffe7 JL |
1535 | |
1536 | fmt = GET_RTX_FORMAT (code); | |
1537 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
1538 | { | |
1539 | switch (fmt[i]) | |
1540 | { | |
9ae8ffe7 JL |
1541 | case 'i': |
1542 | if (XINT (x, i) != XINT (y, i)) | |
1543 | return 0; | |
1544 | break; | |
1545 | ||
9ae8ffe7 JL |
1546 | case 'E': |
1547 | /* Two vectors must have the same length. */ | |
1548 | if (XVECLEN (x, i) != XVECLEN (y, i)) | |
1549 | return 0; | |
1550 | ||
1551 | /* And the corresponding elements must match. */ | |
1552 | for (j = 0; j < XVECLEN (x, i); j++) | |
45183e03 JH |
1553 | if (rtx_equal_for_memref_p (canon_rtx (XVECEXP (x, i, j)), |
1554 | canon_rtx (XVECEXP (y, i, j))) == 0) | |
9ae8ffe7 JL |
1555 | return 0; |
1556 | break; | |
1557 | ||
1558 | case 'e': | |
45183e03 JH |
1559 | if (rtx_equal_for_memref_p (canon_rtx (XEXP (x, i)), |
1560 | canon_rtx (XEXP (y, i))) == 0) | |
9ae8ffe7 JL |
1561 | return 0; |
1562 | break; | |
1563 | ||
3237ac18 AH |
1564 | /* This can happen for asm operands. */ |
1565 | case 's': | |
1566 | if (strcmp (XSTR (x, i), XSTR (y, i))) | |
1567 | return 0; | |
1568 | break; | |
1569 | ||
aee21ba9 JL |
1570 | /* This can happen for an asm which clobbers memory. */ |
1571 | case '0': | |
1572 | break; | |
1573 | ||
9ae8ffe7 JL |
1574 | /* It is believed that rtx's at this level will never |
1575 | contain anything but integers and other rtx's, | |
1576 | except for within LABEL_REFs and SYMBOL_REFs. */ | |
1577 | default: | |
298e6adc | 1578 | gcc_unreachable (); |
9ae8ffe7 JL |
1579 | } |
1580 | } | |
1581 | return 1; | |
1582 | } | |
1583 | ||
9e412ca3 | 1584 | static rtx |
4682ae04 | 1585 | find_base_term (rtx x) |
9ae8ffe7 | 1586 | { |
eab5c70a | 1587 | cselib_val *val; |
6f2ffb4b AO |
1588 | struct elt_loc_list *l, *f; |
1589 | rtx ret; | |
eab5c70a | 1590 | |
b949ea8b JW |
1591 | #if defined (FIND_BASE_TERM) |
1592 | /* Try machine-dependent ways to find the base term. */ | |
1593 | x = FIND_BASE_TERM (x); | |
1594 | #endif | |
1595 | ||
9ae8ffe7 JL |
1596 | switch (GET_CODE (x)) |
1597 | { | |
1598 | case REG: | |
1599 | return REG_BASE_VALUE (x); | |
1600 | ||
d288e53d | 1601 | case TRUNCATE: |
5932a4d4 | 1602 | /* As we do not know which address space the pointer is referring to, we can |
d4ebfa65 BE |
1603 | handle this only if the target does not support different pointer or |
1604 | address modes depending on the address space. */ | |
1605 | if (!target_default_pointer_address_modes_p ()) | |
1606 | return 0; | |
d288e53d | 1607 | if (GET_MODE_SIZE (GET_MODE (x)) < GET_MODE_SIZE (Pmode)) |
ca7fd9cd | 1608 | return 0; |
d288e53d | 1609 | /* Fall through. */ |
9ae8ffe7 | 1610 | case HIGH: |
6d849a2a JL |
1611 | case PRE_INC: |
1612 | case PRE_DEC: | |
1613 | case POST_INC: | |
1614 | case POST_DEC: | |
d288e53d DE |
1615 | case PRE_MODIFY: |
1616 | case POST_MODIFY: | |
6d849a2a JL |
1617 | return find_base_term (XEXP (x, 0)); |
1618 | ||
1abade85 RK |
1619 | case ZERO_EXTEND: |
1620 | case SIGN_EXTEND: /* Used for Alpha/NT pointers */ | |
5932a4d4 | 1621 | /* As we do not know which address space the pointer is referring to, we can |
d4ebfa65 BE |
1622 | handle this only if the target does not support different pointer or |
1623 | address modes depending on the address space. */ | |
1624 | if (!target_default_pointer_address_modes_p ()) | |
1625 | return 0; | |
1626 | ||
1abade85 RK |
1627 | { |
1628 | rtx temp = find_base_term (XEXP (x, 0)); | |
1629 | ||
5ae6cd0d | 1630 | if (temp != 0 && CONSTANT_P (temp)) |
1abade85 | 1631 | temp = convert_memory_address (Pmode, temp); |
1abade85 RK |
1632 | |
1633 | return temp; | |
1634 | } | |
1635 | ||
eab5c70a BS |
1636 | case VALUE: |
1637 | val = CSELIB_VAL_PTR (x); | |
6f2ffb4b AO |
1638 | ret = NULL_RTX; |
1639 | ||
40e02b4a | 1640 | if (!val) |
6f2ffb4b AO |
1641 | return ret; |
1642 | ||
1643 | f = val->locs; | |
1644 | /* Temporarily reset val->locs to avoid infinite recursion. */ | |
1645 | val->locs = NULL; | |
1646 | ||
1647 | for (l = f; l; l = l->next) | |
1648 | if (GET_CODE (l->loc) == VALUE | |
1649 | && CSELIB_VAL_PTR (l->loc)->locs | |
1650 | && !CSELIB_VAL_PTR (l->loc)->locs->next | |
1651 | && CSELIB_VAL_PTR (l->loc)->locs->loc == x) | |
1652 | continue; | |
1653 | else if ((ret = find_base_term (l->loc)) != 0) | |
1654 | break; | |
1655 | ||
1656 | val->locs = f; | |
1657 | return ret; | |
eab5c70a | 1658 | |
023f059b JJ |
1659 | case LO_SUM: |
1660 | /* The standard form is (lo_sum reg sym) so look only at the | |
1661 | second operand. */ | |
1662 | return find_base_term (XEXP (x, 1)); | |
1663 | ||
9ae8ffe7 JL |
1664 | case CONST: |
1665 | x = XEXP (x, 0); | |
1666 | if (GET_CODE (x) != PLUS && GET_CODE (x) != MINUS) | |
1667 | return 0; | |
938d968e | 1668 | /* Fall through. */ |
9ae8ffe7 JL |
1669 | case PLUS: |
1670 | case MINUS: | |
1671 | { | |
3c567fae JL |
1672 | rtx tmp1 = XEXP (x, 0); |
1673 | rtx tmp2 = XEXP (x, 1); | |
1674 | ||
f5143c46 | 1675 | /* This is a little bit tricky since we have to determine which of |
3c567fae JL |
1676 | the two operands represents the real base address. Otherwise this |
1677 | routine may return the index register instead of the base register. | |
1678 | ||
1679 | That may cause us to believe no aliasing was possible, when in | |
1680 | fact aliasing is possible. | |
1681 | ||
1682 | We use a few simple tests to guess the base register. Additional | |
1683 | tests can certainly be added. For example, if one of the operands | |
1684 | is a shift or multiply, then it must be the index register and the | |
1685 | other operand is the base register. */ | |
ca7fd9cd | 1686 | |
b949ea8b JW |
1687 | if (tmp1 == pic_offset_table_rtx && CONSTANT_P (tmp2)) |
1688 | return find_base_term (tmp2); | |
1689 | ||
3c567fae JL |
1690 | /* If either operand is known to be a pointer, then use it |
1691 | to determine the base term. */ | |
3502dc9c | 1692 | if (REG_P (tmp1) && REG_POINTER (tmp1)) |
7eba2d1f LM |
1693 | { |
1694 | rtx base = find_base_term (tmp1); | |
1695 | if (base) | |
1696 | return base; | |
1697 | } | |
3c567fae | 1698 | |
3502dc9c | 1699 | if (REG_P (tmp2) && REG_POINTER (tmp2)) |
7eba2d1f LM |
1700 | { |
1701 | rtx base = find_base_term (tmp2); | |
1702 | if (base) | |
1703 | return base; | |
1704 | } | |
3c567fae JL |
1705 | |
1706 | /* Neither operand was known to be a pointer. Go ahead and find the | |
1707 | base term for both operands. */ | |
1708 | tmp1 = find_base_term (tmp1); | |
1709 | tmp2 = find_base_term (tmp2); | |
1710 | ||
1711 | /* If either base term is named object or a special address | |
1712 | (like an argument or stack reference), then use it for the | |
1713 | base term. */ | |
9fc37b2b | 1714 | if (tmp1 != 0 && known_base_value_p (tmp1)) |
3c567fae JL |
1715 | return tmp1; |
1716 | ||
9fc37b2b | 1717 | if (tmp2 != 0 && known_base_value_p (tmp2)) |
3c567fae JL |
1718 | return tmp2; |
1719 | ||
1720 | /* We could not determine which of the two operands was the | |
1721 | base register and which was the index. So we can determine | |
1722 | nothing from the base alias check. */ | |
1723 | return 0; | |
9ae8ffe7 JL |
1724 | } |
1725 | ||
1726 | case AND: | |
481683e1 | 1727 | if (CONST_INT_P (XEXP (x, 1)) && INTVAL (XEXP (x, 1)) != 0) |
d288e53d | 1728 | return find_base_term (XEXP (x, 0)); |
9ae8ffe7 JL |
1729 | return 0; |
1730 | ||
1731 | case SYMBOL_REF: | |
1732 | case LABEL_REF: | |
1733 | return x; | |
1734 | ||
1735 | default: | |
1736 | return 0; | |
1737 | } | |
1738 | } | |
1739 | ||
9e412ca3 RS |
1740 | /* Return true if accesses to address X may alias accesses based |
1741 | on the stack pointer. */ | |
1742 | ||
1743 | bool | |
1744 | may_be_sp_based_p (rtx x) | |
1745 | { | |
1746 | rtx base = find_base_term (x); | |
1747 | return !base || base == static_reg_base_value[STACK_POINTER_REGNUM]; | |
1748 | } | |
1749 | ||
9ae8ffe7 JL |
1750 | /* Return 0 if the addresses X and Y are known to point to different |
1751 | objects, 1 if they might be pointers to the same object. */ | |
1752 | ||
1753 | static int | |
4682ae04 AJ |
1754 | base_alias_check (rtx x, rtx y, enum machine_mode x_mode, |
1755 | enum machine_mode y_mode) | |
9ae8ffe7 JL |
1756 | { |
1757 | rtx x_base = find_base_term (x); | |
1758 | rtx y_base = find_base_term (y); | |
1759 | ||
1c72c7f6 JC |
1760 | /* If the address itself has no known base see if a known equivalent |
1761 | value has one. If either address still has no known base, nothing | |
1762 | is known about aliasing. */ | |
1763 | if (x_base == 0) | |
1764 | { | |
1765 | rtx x_c; | |
d4b60170 | 1766 | |
1c72c7f6 JC |
1767 | if (! flag_expensive_optimizations || (x_c = canon_rtx (x)) == x) |
1768 | return 1; | |
d4b60170 | 1769 | |
1c72c7f6 JC |
1770 | x_base = find_base_term (x_c); |
1771 | if (x_base == 0) | |
1772 | return 1; | |
1773 | } | |
9ae8ffe7 | 1774 | |
1c72c7f6 JC |
1775 | if (y_base == 0) |
1776 | { | |
1777 | rtx y_c; | |
1778 | if (! flag_expensive_optimizations || (y_c = canon_rtx (y)) == y) | |
1779 | return 1; | |
d4b60170 | 1780 | |
1c72c7f6 JC |
1781 | y_base = find_base_term (y_c); |
1782 | if (y_base == 0) | |
1783 | return 1; | |
1784 | } | |
1785 | ||
1786 | /* If the base addresses are equal nothing is known about aliasing. */ | |
1787 | if (rtx_equal_p (x_base, y_base)) | |
9ae8ffe7 JL |
1788 | return 1; |
1789 | ||
435da628 UB |
1790 | /* The base addresses are different expressions. If they are not accessed |
1791 | via AND, there is no conflict. We can bring knowledge of object | |
1792 | alignment into play here. For example, on alpha, "char a, b;" can | |
1793 | alias one another, though "char a; long b;" cannot. AND addesses may | |
1794 | implicitly alias surrounding objects; i.e. unaligned access in DImode | |
1795 | via AND address can alias all surrounding object types except those | |
1796 | with aligment 8 or higher. */ | |
1797 | if (GET_CODE (x) == AND && GET_CODE (y) == AND) | |
1798 | return 1; | |
1799 | if (GET_CODE (x) == AND | |
481683e1 | 1800 | && (!CONST_INT_P (XEXP (x, 1)) |
435da628 UB |
1801 | || (int) GET_MODE_UNIT_SIZE (y_mode) < -INTVAL (XEXP (x, 1)))) |
1802 | return 1; | |
1803 | if (GET_CODE (y) == AND | |
481683e1 | 1804 | && (!CONST_INT_P (XEXP (y, 1)) |
435da628 UB |
1805 | || (int) GET_MODE_UNIT_SIZE (x_mode) < -INTVAL (XEXP (y, 1)))) |
1806 | return 1; | |
1807 | ||
1808 | /* Differing symbols not accessed via AND never alias. */ | |
9ae8ffe7 | 1809 | if (GET_CODE (x_base) != ADDRESS && GET_CODE (y_base) != ADDRESS) |
435da628 | 1810 | return 0; |
9ae8ffe7 | 1811 | |
9fc37b2b | 1812 | if (unique_base_value_p (x_base) || unique_base_value_p (y_base)) |
9ae8ffe7 JL |
1813 | return 0; |
1814 | ||
0d3c82d6 | 1815 | return 1; |
9ae8ffe7 JL |
1816 | } |
1817 | ||
a5628378 AO |
1818 | /* Callback for for_each_rtx, that returns 1 upon encountering a VALUE |
1819 | whose UID is greater than the int uid that D points to. */ | |
1820 | ||
1821 | static int | |
1822 | refs_newer_value_cb (rtx *x, void *d) | |
1823 | { | |
1824 | if (GET_CODE (*x) == VALUE && CSELIB_VAL_PTR (*x)->uid > *(int *)d) | |
1825 | return 1; | |
1826 | ||
1827 | return 0; | |
1828 | } | |
1829 | ||
1830 | /* Return TRUE if EXPR refers to a VALUE whose uid is greater than | |
1831 | that of V. */ | |
1832 | ||
1833 | static bool | |
1834 | refs_newer_value_p (rtx expr, rtx v) | |
1835 | { | |
1836 | int minuid = CSELIB_VAL_PTR (v)->uid; | |
1837 | ||
1838 | return for_each_rtx (&expr, refs_newer_value_cb, &minuid); | |
1839 | } | |
1840 | ||
eab5c70a BS |
1841 | /* Convert the address X into something we can use. This is done by returning |
1842 | it unchanged unless it is a value; in the latter case we call cselib to get | |
1843 | a more useful rtx. */ | |
3bdf5ad1 | 1844 | |
a13d4ebf | 1845 | rtx |
4682ae04 | 1846 | get_addr (rtx x) |
eab5c70a BS |
1847 | { |
1848 | cselib_val *v; | |
1849 | struct elt_loc_list *l; | |
1850 | ||
1851 | if (GET_CODE (x) != VALUE) | |
1852 | return x; | |
1853 | v = CSELIB_VAL_PTR (x); | |
40e02b4a JH |
1854 | if (v) |
1855 | { | |
0f68ba3e AO |
1856 | bool have_equivs = cselib_have_permanent_equivalences (); |
1857 | if (have_equivs) | |
1858 | v = canonical_cselib_val (v); | |
40e02b4a JH |
1859 | for (l = v->locs; l; l = l->next) |
1860 | if (CONSTANT_P (l->loc)) | |
1861 | return l->loc; | |
1862 | for (l = v->locs; l; l = l->next) | |
0f68ba3e AO |
1863 | if (!REG_P (l->loc) && !MEM_P (l->loc) |
1864 | /* Avoid infinite recursion when potentially dealing with | |
1865 | var-tracking artificial equivalences, by skipping the | |
1866 | equivalences themselves, and not choosing expressions | |
1867 | that refer to newer VALUEs. */ | |
1868 | && (!have_equivs | |
1869 | || (GET_CODE (l->loc) != VALUE | |
1870 | && !refs_newer_value_p (l->loc, x)))) | |
a5628378 | 1871 | return l->loc; |
0f68ba3e AO |
1872 | if (have_equivs) |
1873 | { | |
1874 | for (l = v->locs; l; l = l->next) | |
1875 | if (REG_P (l->loc) | |
1876 | || (GET_CODE (l->loc) != VALUE | |
1877 | && !refs_newer_value_p (l->loc, x))) | |
1878 | return l->loc; | |
1879 | /* Return the canonical value. */ | |
1880 | return v->val_rtx; | |
1881 | } | |
1882 | if (v->locs) | |
1883 | return v->locs->loc; | |
40e02b4a | 1884 | } |
eab5c70a BS |
1885 | return x; |
1886 | } | |
1887 | ||
39cec1ac MH |
1888 | /* Return the address of the (N_REFS + 1)th memory reference to ADDR |
1889 | where SIZE is the size in bytes of the memory reference. If ADDR | |
1890 | is not modified by the memory reference then ADDR is returned. */ | |
1891 | ||
04e2b4d3 | 1892 | static rtx |
4682ae04 | 1893 | addr_side_effect_eval (rtx addr, int size, int n_refs) |
39cec1ac MH |
1894 | { |
1895 | int offset = 0; | |
ca7fd9cd | 1896 | |
39cec1ac MH |
1897 | switch (GET_CODE (addr)) |
1898 | { | |
1899 | case PRE_INC: | |
1900 | offset = (n_refs + 1) * size; | |
1901 | break; | |
1902 | case PRE_DEC: | |
1903 | offset = -(n_refs + 1) * size; | |
1904 | break; | |
1905 | case POST_INC: | |
1906 | offset = n_refs * size; | |
1907 | break; | |
1908 | case POST_DEC: | |
1909 | offset = -n_refs * size; | |
1910 | break; | |
1911 | ||
1912 | default: | |
1913 | return addr; | |
1914 | } | |
ca7fd9cd | 1915 | |
39cec1ac | 1916 | if (offset) |
45183e03 | 1917 | addr = gen_rtx_PLUS (GET_MODE (addr), XEXP (addr, 0), |
c22cacf3 | 1918 | GEN_INT (offset)); |
39cec1ac MH |
1919 | else |
1920 | addr = XEXP (addr, 0); | |
45183e03 | 1921 | addr = canon_rtx (addr); |
39cec1ac MH |
1922 | |
1923 | return addr; | |
1924 | } | |
1925 | ||
f47e08d9 RG |
1926 | /* Return one if X and Y (memory addresses) reference the |
1927 | same location in memory or if the references overlap. | |
1928 | Return zero if they do not overlap, else return | |
1929 | minus one in which case they still might reference the same location. | |
1930 | ||
1931 | C is an offset accumulator. When | |
9ae8ffe7 JL |
1932 | C is nonzero, we are testing aliases between X and Y + C. |
1933 | XSIZE is the size in bytes of the X reference, | |
1934 | similarly YSIZE is the size in bytes for Y. | |
45183e03 | 1935 | Expect that canon_rtx has been already called for X and Y. |
9ae8ffe7 JL |
1936 | |
1937 | If XSIZE or YSIZE is zero, we do not know the amount of memory being | |
1938 | referenced (the reference was BLKmode), so make the most pessimistic | |
1939 | assumptions. | |
1940 | ||
c02f035f RH |
1941 | If XSIZE or YSIZE is negative, we may access memory outside the object |
1942 | being referenced as a side effect. This can happen when using AND to | |
1943 | align memory references, as is done on the Alpha. | |
1944 | ||
9ae8ffe7 | 1945 | Nice to notice that varying addresses cannot conflict with fp if no |
f47e08d9 RG |
1946 | local variables had their addresses taken, but that's too hard now. |
1947 | ||
1948 | ??? Contrary to the tree alias oracle this does not return | |
1949 | one for X + non-constant and Y + non-constant when X and Y are equal. | |
1950 | If that is fixed the TBAA hack for union type-punning can be removed. */ | |
9ae8ffe7 | 1951 | |
9ae8ffe7 | 1952 | static int |
4682ae04 | 1953 | memrefs_conflict_p (int xsize, rtx x, int ysize, rtx y, HOST_WIDE_INT c) |
9ae8ffe7 | 1954 | { |
eab5c70a | 1955 | if (GET_CODE (x) == VALUE) |
5312b066 JJ |
1956 | { |
1957 | if (REG_P (y)) | |
1958 | { | |
24f8d71e JJ |
1959 | struct elt_loc_list *l = NULL; |
1960 | if (CSELIB_VAL_PTR (x)) | |
a5628378 AO |
1961 | for (l = canonical_cselib_val (CSELIB_VAL_PTR (x))->locs; |
1962 | l; l = l->next) | |
24f8d71e JJ |
1963 | if (REG_P (l->loc) && rtx_equal_for_memref_p (l->loc, y)) |
1964 | break; | |
5312b066 JJ |
1965 | if (l) |
1966 | x = y; | |
1967 | else | |
1968 | x = get_addr (x); | |
1969 | } | |
1970 | /* Don't call get_addr if y is the same VALUE. */ | |
1971 | else if (x != y) | |
1972 | x = get_addr (x); | |
1973 | } | |
eab5c70a | 1974 | if (GET_CODE (y) == VALUE) |
5312b066 JJ |
1975 | { |
1976 | if (REG_P (x)) | |
1977 | { | |
24f8d71e JJ |
1978 | struct elt_loc_list *l = NULL; |
1979 | if (CSELIB_VAL_PTR (y)) | |
a5628378 AO |
1980 | for (l = canonical_cselib_val (CSELIB_VAL_PTR (y))->locs; |
1981 | l; l = l->next) | |
24f8d71e JJ |
1982 | if (REG_P (l->loc) && rtx_equal_for_memref_p (l->loc, x)) |
1983 | break; | |
5312b066 JJ |
1984 | if (l) |
1985 | y = x; | |
1986 | else | |
1987 | y = get_addr (y); | |
1988 | } | |
1989 | /* Don't call get_addr if x is the same VALUE. */ | |
1990 | else if (y != x) | |
1991 | y = get_addr (y); | |
1992 | } | |
9ae8ffe7 JL |
1993 | if (GET_CODE (x) == HIGH) |
1994 | x = XEXP (x, 0); | |
1995 | else if (GET_CODE (x) == LO_SUM) | |
1996 | x = XEXP (x, 1); | |
1997 | else | |
45183e03 | 1998 | x = addr_side_effect_eval (x, xsize, 0); |
9ae8ffe7 JL |
1999 | if (GET_CODE (y) == HIGH) |
2000 | y = XEXP (y, 0); | |
2001 | else if (GET_CODE (y) == LO_SUM) | |
2002 | y = XEXP (y, 1); | |
2003 | else | |
45183e03 | 2004 | y = addr_side_effect_eval (y, ysize, 0); |
9ae8ffe7 JL |
2005 | |
2006 | if (rtx_equal_for_memref_p (x, y)) | |
2007 | { | |
c02f035f | 2008 | if (xsize <= 0 || ysize <= 0) |
9ae8ffe7 JL |
2009 | return 1; |
2010 | if (c >= 0 && xsize > c) | |
2011 | return 1; | |
2012 | if (c < 0 && ysize+c > 0) | |
2013 | return 1; | |
2014 | return 0; | |
2015 | } | |
2016 | ||
6e73e666 JC |
2017 | /* This code used to check for conflicts involving stack references and |
2018 | globals but the base address alias code now handles these cases. */ | |
9ae8ffe7 JL |
2019 | |
2020 | if (GET_CODE (x) == PLUS) | |
2021 | { | |
2022 | /* The fact that X is canonicalized means that this | |
2023 | PLUS rtx is canonicalized. */ | |
2024 | rtx x0 = XEXP (x, 0); | |
2025 | rtx x1 = XEXP (x, 1); | |
2026 | ||
2027 | if (GET_CODE (y) == PLUS) | |
2028 | { | |
2029 | /* The fact that Y is canonicalized means that this | |
2030 | PLUS rtx is canonicalized. */ | |
2031 | rtx y0 = XEXP (y, 0); | |
2032 | rtx y1 = XEXP (y, 1); | |
2033 | ||
2034 | if (rtx_equal_for_memref_p (x1, y1)) | |
2035 | return memrefs_conflict_p (xsize, x0, ysize, y0, c); | |
2036 | if (rtx_equal_for_memref_p (x0, y0)) | |
2037 | return memrefs_conflict_p (xsize, x1, ysize, y1, c); | |
481683e1 | 2038 | if (CONST_INT_P (x1)) |
63be02db | 2039 | { |
481683e1 | 2040 | if (CONST_INT_P (y1)) |
63be02db JM |
2041 | return memrefs_conflict_p (xsize, x0, ysize, y0, |
2042 | c - INTVAL (x1) + INTVAL (y1)); | |
2043 | else | |
2044 | return memrefs_conflict_p (xsize, x0, ysize, y, | |
2045 | c - INTVAL (x1)); | |
2046 | } | |
481683e1 | 2047 | else if (CONST_INT_P (y1)) |
9ae8ffe7 JL |
2048 | return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1)); |
2049 | ||
f47e08d9 | 2050 | return -1; |
9ae8ffe7 | 2051 | } |
481683e1 | 2052 | else if (CONST_INT_P (x1)) |
9ae8ffe7 JL |
2053 | return memrefs_conflict_p (xsize, x0, ysize, y, c - INTVAL (x1)); |
2054 | } | |
2055 | else if (GET_CODE (y) == PLUS) | |
2056 | { | |
2057 | /* The fact that Y is canonicalized means that this | |
2058 | PLUS rtx is canonicalized. */ | |
2059 | rtx y0 = XEXP (y, 0); | |
2060 | rtx y1 = XEXP (y, 1); | |
2061 | ||
481683e1 | 2062 | if (CONST_INT_P (y1)) |
9ae8ffe7 JL |
2063 | return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1)); |
2064 | else | |
f47e08d9 | 2065 | return -1; |
9ae8ffe7 JL |
2066 | } |
2067 | ||
2068 | if (GET_CODE (x) == GET_CODE (y)) | |
2069 | switch (GET_CODE (x)) | |
2070 | { | |
2071 | case MULT: | |
2072 | { | |
2073 | /* Handle cases where we expect the second operands to be the | |
2074 | same, and check only whether the first operand would conflict | |
2075 | or not. */ | |
2076 | rtx x0, y0; | |
2077 | rtx x1 = canon_rtx (XEXP (x, 1)); | |
2078 | rtx y1 = canon_rtx (XEXP (y, 1)); | |
2079 | if (! rtx_equal_for_memref_p (x1, y1)) | |
f47e08d9 | 2080 | return -1; |
9ae8ffe7 JL |
2081 | x0 = canon_rtx (XEXP (x, 0)); |
2082 | y0 = canon_rtx (XEXP (y, 0)); | |
2083 | if (rtx_equal_for_memref_p (x0, y0)) | |
2084 | return (xsize == 0 || ysize == 0 | |
2085 | || (c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)); | |
2086 | ||
2087 | /* Can't properly adjust our sizes. */ | |
481683e1 | 2088 | if (!CONST_INT_P (x1)) |
f47e08d9 | 2089 | return -1; |
9ae8ffe7 JL |
2090 | xsize /= INTVAL (x1); |
2091 | ysize /= INTVAL (x1); | |
2092 | c /= INTVAL (x1); | |
2093 | return memrefs_conflict_p (xsize, x0, ysize, y0, c); | |
2094 | } | |
1d300e19 KG |
2095 | |
2096 | default: | |
2097 | break; | |
9ae8ffe7 JL |
2098 | } |
2099 | ||
a9bf4fe2 AO |
2100 | /* Deal with alignment ANDs by adjusting offset and size so as to |
2101 | cover the maximum range, without taking any previously known | |
2102 | alignment into account. */ | |
481683e1 | 2103 | if (GET_CODE (x) == AND && CONST_INT_P (XEXP (x, 1))) |
56ee9281 | 2104 | { |
a9bf4fe2 AO |
2105 | HOST_WIDE_INT sc = INTVAL (XEXP (x, 1)); |
2106 | unsigned HOST_WIDE_INT uc = sc; | |
2107 | if (xsize > 0 && sc < 0 && -uc == (uc & -uc)) | |
2108 | { | |
2109 | xsize -= sc + 1; | |
fe8fb1c4 | 2110 | c -= sc + 1; |
a9bf4fe2 AO |
2111 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), |
2112 | ysize, y, c); | |
2113 | } | |
56ee9281 | 2114 | } |
481683e1 | 2115 | if (GET_CODE (y) == AND && CONST_INT_P (XEXP (y, 1))) |
c02f035f | 2116 | { |
a9bf4fe2 AO |
2117 | HOST_WIDE_INT sc = INTVAL (XEXP (y, 1)); |
2118 | unsigned HOST_WIDE_INT uc = sc; | |
2119 | if (ysize > 0 && sc < 0 && -uc == (uc & -uc)) | |
2120 | { | |
2121 | ysize -= sc + 1; | |
fe8fb1c4 | 2122 | c += sc + 1; |
a9bf4fe2 AO |
2123 | return memrefs_conflict_p (xsize, x, |
2124 | ysize, canon_rtx (XEXP (y, 0)), c); | |
2125 | } | |
c02f035f | 2126 | } |
9ae8ffe7 JL |
2127 | |
2128 | if (CONSTANT_P (x)) | |
2129 | { | |
481683e1 | 2130 | if (CONST_INT_P (x) && CONST_INT_P (y)) |
9ae8ffe7 JL |
2131 | { |
2132 | c += (INTVAL (y) - INTVAL (x)); | |
c02f035f | 2133 | return (xsize <= 0 || ysize <= 0 |
9ae8ffe7 JL |
2134 | || (c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)); |
2135 | } | |
2136 | ||
2137 | if (GET_CODE (x) == CONST) | |
2138 | { | |
2139 | if (GET_CODE (y) == CONST) | |
2140 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), | |
2141 | ysize, canon_rtx (XEXP (y, 0)), c); | |
2142 | else | |
2143 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), | |
2144 | ysize, y, c); | |
2145 | } | |
2146 | if (GET_CODE (y) == CONST) | |
2147 | return memrefs_conflict_p (xsize, x, ysize, | |
2148 | canon_rtx (XEXP (y, 0)), c); | |
2149 | ||
2150 | if (CONSTANT_P (y)) | |
b949ea8b | 2151 | return (xsize <= 0 || ysize <= 0 |
c02f035f | 2152 | || (rtx_equal_for_memref_p (x, y) |
b949ea8b | 2153 | && ((c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)))); |
9ae8ffe7 | 2154 | |
f47e08d9 | 2155 | return -1; |
9ae8ffe7 | 2156 | } |
f47e08d9 RG |
2157 | |
2158 | return -1; | |
9ae8ffe7 JL |
2159 | } |
2160 | ||
2161 | /* Functions to compute memory dependencies. | |
2162 | ||
2163 | Since we process the insns in execution order, we can build tables | |
2164 | to keep track of what registers are fixed (and not aliased), what registers | |
2165 | are varying in known ways, and what registers are varying in unknown | |
2166 | ways. | |
2167 | ||
2168 | If both memory references are volatile, then there must always be a | |
2169 | dependence between the two references, since their order can not be | |
2170 | changed. A volatile and non-volatile reference can be interchanged | |
ca7fd9cd | 2171 | though. |
9ae8ffe7 | 2172 | |
53d9622b RS |
2173 | We also must allow AND addresses, because they may generate accesses |
2174 | outside the object being referenced. This is used to generate aligned | |
2175 | addresses from unaligned addresses, for instance, the alpha | |
dc1618bc | 2176 | storeqi_unaligned pattern. */ |
9ae8ffe7 JL |
2177 | |
2178 | /* Read dependence: X is read after read in MEM takes place. There can | |
2179 | only be a dependence here if both reads are volatile. */ | |
2180 | ||
2181 | int | |
4f588890 | 2182 | read_dependence (const_rtx mem, const_rtx x) |
9ae8ffe7 JL |
2183 | { |
2184 | return MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem); | |
2185 | } | |
2186 | ||
998d7deb RH |
2187 | /* Return true if we can determine that the fields referenced cannot |
2188 | overlap for any pair of objects. */ | |
2189 | ||
2190 | static bool | |
175a7536 | 2191 | nonoverlapping_component_refs_p (const_rtx rtlx, const_rtx rtly) |
998d7deb | 2192 | { |
175a7536 | 2193 | const_tree x = MEM_EXPR (rtlx), y = MEM_EXPR (rtly); |
4f588890 | 2194 | const_tree fieldx, fieldy, typex, typey, orig_y; |
998d7deb | 2195 | |
175a7536 MM |
2196 | if (!flag_strict_aliasing |
2197 | || !x || !y | |
2198 | || TREE_CODE (x) != COMPONENT_REF | |
2199 | || TREE_CODE (y) != COMPONENT_REF) | |
4c7af939 AB |
2200 | return false; |
2201 | ||
998d7deb RH |
2202 | do |
2203 | { | |
2204 | /* The comparison has to be done at a common type, since we don't | |
d6a7951f | 2205 | know how the inheritance hierarchy works. */ |
998d7deb RH |
2206 | orig_y = y; |
2207 | do | |
2208 | { | |
2209 | fieldx = TREE_OPERAND (x, 1); | |
c05a0766 | 2210 | typex = TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (fieldx)); |
998d7deb RH |
2211 | |
2212 | y = orig_y; | |
2213 | do | |
2214 | { | |
2215 | fieldy = TREE_OPERAND (y, 1); | |
c05a0766 | 2216 | typey = TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (fieldy)); |
998d7deb RH |
2217 | |
2218 | if (typex == typey) | |
2219 | goto found; | |
2220 | ||
2221 | y = TREE_OPERAND (y, 0); | |
2222 | } | |
2223 | while (y && TREE_CODE (y) == COMPONENT_REF); | |
2224 | ||
2225 | x = TREE_OPERAND (x, 0); | |
2226 | } | |
2227 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
998d7deb | 2228 | /* Never found a common type. */ |
c05a0766 | 2229 | return false; |
998d7deb RH |
2230 | |
2231 | found: | |
2232 | /* If we're left with accessing different fields of a structure, | |
2233 | then no overlap. */ | |
2234 | if (TREE_CODE (typex) == RECORD_TYPE | |
2235 | && fieldx != fieldy) | |
2236 | return true; | |
2237 | ||
2238 | /* The comparison on the current field failed. If we're accessing | |
2239 | a very nested structure, look at the next outer level. */ | |
2240 | x = TREE_OPERAND (x, 0); | |
2241 | y = TREE_OPERAND (y, 0); | |
2242 | } | |
2243 | while (x && y | |
2244 | && TREE_CODE (x) == COMPONENT_REF | |
2245 | && TREE_CODE (y) == COMPONENT_REF); | |
ca7fd9cd | 2246 | |
998d7deb RH |
2247 | return false; |
2248 | } | |
2249 | ||
2250 | /* Look at the bottom of the COMPONENT_REF list for a DECL, and return it. */ | |
2251 | ||
2252 | static tree | |
4682ae04 | 2253 | decl_for_component_ref (tree x) |
998d7deb RH |
2254 | { |
2255 | do | |
2256 | { | |
2257 | x = TREE_OPERAND (x, 0); | |
2258 | } | |
2259 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
2260 | ||
2261 | return x && DECL_P (x) ? x : NULL_TREE; | |
2262 | } | |
2263 | ||
527210c4 RS |
2264 | /* Walk up the COMPONENT_REF list in X and adjust *OFFSET to compensate |
2265 | for the offset of the field reference. *KNOWN_P says whether the | |
2266 | offset is known. */ | |
998d7deb | 2267 | |
527210c4 RS |
2268 | static void |
2269 | adjust_offset_for_component_ref (tree x, bool *known_p, | |
2270 | HOST_WIDE_INT *offset) | |
998d7deb | 2271 | { |
527210c4 RS |
2272 | if (!*known_p) |
2273 | return; | |
ca7fd9cd | 2274 | do |
998d7deb | 2275 | { |
527210c4 | 2276 | tree xoffset = component_ref_field_offset (x); |
998d7deb RH |
2277 | tree field = TREE_OPERAND (x, 1); |
2278 | ||
527210c4 RS |
2279 | if (! host_integerp (xoffset, 1)) |
2280 | { | |
2281 | *known_p = false; | |
2282 | return; | |
2283 | } | |
2284 | *offset += (tree_low_cst (xoffset, 1) | |
998d7deb RH |
2285 | + (tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1) |
2286 | / BITS_PER_UNIT)); | |
2287 | ||
2288 | x = TREE_OPERAND (x, 0); | |
2289 | } | |
2290 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
998d7deb RH |
2291 | } |
2292 | ||
95bd1dd7 | 2293 | /* Return nonzero if we can determine the exprs corresponding to memrefs |
c6ea834c BM |
2294 | X and Y and they do not overlap. |
2295 | If LOOP_VARIANT is set, skip offset-based disambiguation */ | |
a4311dfe | 2296 | |
2e4e39f6 | 2297 | int |
c6ea834c | 2298 | nonoverlapping_memrefs_p (const_rtx x, const_rtx y, bool loop_invariant) |
a4311dfe | 2299 | { |
998d7deb | 2300 | tree exprx = MEM_EXPR (x), expry = MEM_EXPR (y); |
a4311dfe RK |
2301 | rtx rtlx, rtly; |
2302 | rtx basex, basey; | |
527210c4 RS |
2303 | bool moffsetx_known_p, moffsety_known_p; |
2304 | HOST_WIDE_INT moffsetx = 0, moffsety = 0; | |
a4311dfe RK |
2305 | HOST_WIDE_INT offsetx = 0, offsety = 0, sizex, sizey, tem; |
2306 | ||
998d7deb RH |
2307 | /* Unless both have exprs, we can't tell anything. */ |
2308 | if (exprx == 0 || expry == 0) | |
2309 | return 0; | |
2b22e382 RG |
2310 | |
2311 | /* For spill-slot accesses make sure we have valid offsets. */ | |
2312 | if ((exprx == get_spill_slot_decl (false) | |
527210c4 | 2313 | && ! MEM_OFFSET_KNOWN_P (x)) |
2b22e382 | 2314 | || (expry == get_spill_slot_decl (false) |
527210c4 | 2315 | && ! MEM_OFFSET_KNOWN_P (y))) |
2b22e382 | 2316 | return 0; |
c22cacf3 | 2317 | |
998d7deb | 2318 | /* If the field reference test failed, look at the DECLs involved. */ |
527210c4 RS |
2319 | moffsetx_known_p = MEM_OFFSET_KNOWN_P (x); |
2320 | if (moffsetx_known_p) | |
2321 | moffsetx = MEM_OFFSET (x); | |
998d7deb RH |
2322 | if (TREE_CODE (exprx) == COMPONENT_REF) |
2323 | { | |
2e0c984c RG |
2324 | tree t = decl_for_component_ref (exprx); |
2325 | if (! t) | |
2326 | return 0; | |
527210c4 | 2327 | adjust_offset_for_component_ref (exprx, &moffsetx_known_p, &moffsetx); |
2e0c984c | 2328 | exprx = t; |
998d7deb | 2329 | } |
c67a1cf6 | 2330 | |
527210c4 RS |
2331 | moffsety_known_p = MEM_OFFSET_KNOWN_P (y); |
2332 | if (moffsety_known_p) | |
2333 | moffsety = MEM_OFFSET (y); | |
998d7deb RH |
2334 | if (TREE_CODE (expry) == COMPONENT_REF) |
2335 | { | |
2e0c984c RG |
2336 | tree t = decl_for_component_ref (expry); |
2337 | if (! t) | |
2338 | return 0; | |
527210c4 | 2339 | adjust_offset_for_component_ref (expry, &moffsety_known_p, &moffsety); |
2e0c984c | 2340 | expry = t; |
998d7deb RH |
2341 | } |
2342 | ||
2343 | if (! DECL_P (exprx) || ! DECL_P (expry)) | |
a4311dfe RK |
2344 | return 0; |
2345 | ||
1307c758 RG |
2346 | /* With invalid code we can end up storing into the constant pool. |
2347 | Bail out to avoid ICEing when creating RTL for this. | |
2348 | See gfortran.dg/lto/20091028-2_0.f90. */ | |
2349 | if (TREE_CODE (exprx) == CONST_DECL | |
2350 | || TREE_CODE (expry) == CONST_DECL) | |
2351 | return 1; | |
2352 | ||
998d7deb RH |
2353 | rtlx = DECL_RTL (exprx); |
2354 | rtly = DECL_RTL (expry); | |
a4311dfe | 2355 | |
1edcd60b RK |
2356 | /* If either RTL is not a MEM, it must be a REG or CONCAT, meaning they |
2357 | can't overlap unless they are the same because we never reuse that part | |
2358 | of the stack frame used for locals for spilled pseudos. */ | |
3c0cb5de | 2359 | if ((!MEM_P (rtlx) || !MEM_P (rtly)) |
1edcd60b | 2360 | && ! rtx_equal_p (rtlx, rtly)) |
a4311dfe RK |
2361 | return 1; |
2362 | ||
5932a4d4 | 2363 | /* If we have MEMs referring to different address spaces (which can |
09e881c9 BE |
2364 | potentially overlap), we cannot easily tell from the addresses |
2365 | whether the references overlap. */ | |
2366 | if (MEM_P (rtlx) && MEM_P (rtly) | |
2367 | && MEM_ADDR_SPACE (rtlx) != MEM_ADDR_SPACE (rtly)) | |
2368 | return 0; | |
2369 | ||
a4311dfe RK |
2370 | /* Get the base and offsets of both decls. If either is a register, we |
2371 | know both are and are the same, so use that as the base. The only | |
2372 | we can avoid overlap is if we can deduce that they are nonoverlapping | |
2373 | pieces of that decl, which is very rare. */ | |
3c0cb5de | 2374 | basex = MEM_P (rtlx) ? XEXP (rtlx, 0) : rtlx; |
481683e1 | 2375 | if (GET_CODE (basex) == PLUS && CONST_INT_P (XEXP (basex, 1))) |
a4311dfe RK |
2376 | offsetx = INTVAL (XEXP (basex, 1)), basex = XEXP (basex, 0); |
2377 | ||
3c0cb5de | 2378 | basey = MEM_P (rtly) ? XEXP (rtly, 0) : rtly; |
481683e1 | 2379 | if (GET_CODE (basey) == PLUS && CONST_INT_P (XEXP (basey, 1))) |
a4311dfe RK |
2380 | offsety = INTVAL (XEXP (basey, 1)), basey = XEXP (basey, 0); |
2381 | ||
d746694a | 2382 | /* If the bases are different, we know they do not overlap if both |
ca7fd9cd | 2383 | are constants or if one is a constant and the other a pointer into the |
d746694a RK |
2384 | stack frame. Otherwise a different base means we can't tell if they |
2385 | overlap or not. */ | |
2386 | if (! rtx_equal_p (basex, basey)) | |
ca7fd9cd KH |
2387 | return ((CONSTANT_P (basex) && CONSTANT_P (basey)) |
2388 | || (CONSTANT_P (basex) && REG_P (basey) | |
2389 | && REGNO_PTR_FRAME_P (REGNO (basey))) | |
2390 | || (CONSTANT_P (basey) && REG_P (basex) | |
2391 | && REGNO_PTR_FRAME_P (REGNO (basex)))); | |
a4311dfe | 2392 | |
c6ea834c BM |
2393 | /* Offset based disambiguation not appropriate for loop invariant */ |
2394 | if (loop_invariant) | |
2395 | return 0; | |
2396 | ||
3c0cb5de | 2397 | sizex = (!MEM_P (rtlx) ? (int) GET_MODE_SIZE (GET_MODE (rtlx)) |
f5541398 | 2398 | : MEM_SIZE_KNOWN_P (rtlx) ? MEM_SIZE (rtlx) |
a4311dfe | 2399 | : -1); |
3c0cb5de | 2400 | sizey = (!MEM_P (rtly) ? (int) GET_MODE_SIZE (GET_MODE (rtly)) |
f5541398 RS |
2401 | : MEM_SIZE_KNOWN_P (rtly) ? MEM_SIZE (rtly) |
2402 | : -1); | |
a4311dfe | 2403 | |
0af5bc3e RK |
2404 | /* If we have an offset for either memref, it can update the values computed |
2405 | above. */ | |
527210c4 RS |
2406 | if (moffsetx_known_p) |
2407 | offsetx += moffsetx, sizex -= moffsetx; | |
2408 | if (moffsety_known_p) | |
2409 | offsety += moffsety, sizey -= moffsety; | |
a4311dfe | 2410 | |
0af5bc3e | 2411 | /* If a memref has both a size and an offset, we can use the smaller size. |
efc981bb | 2412 | We can't do this if the offset isn't known because we must view this |
0af5bc3e | 2413 | memref as being anywhere inside the DECL's MEM. */ |
527210c4 | 2414 | if (MEM_SIZE_KNOWN_P (x) && moffsetx_known_p) |
f5541398 | 2415 | sizex = MEM_SIZE (x); |
527210c4 | 2416 | if (MEM_SIZE_KNOWN_P (y) && moffsety_known_p) |
f5541398 | 2417 | sizey = MEM_SIZE (y); |
a4311dfe RK |
2418 | |
2419 | /* Put the values of the memref with the lower offset in X's values. */ | |
2420 | if (offsetx > offsety) | |
2421 | { | |
2422 | tem = offsetx, offsetx = offsety, offsety = tem; | |
2423 | tem = sizex, sizex = sizey, sizey = tem; | |
2424 | } | |
2425 | ||
2426 | /* If we don't know the size of the lower-offset value, we can't tell | |
2427 | if they conflict. Otherwise, we do the test. */ | |
a6f7c915 | 2428 | return sizex >= 0 && offsety >= offsetx + sizex; |
a4311dfe RK |
2429 | } |
2430 | ||
9362286d SB |
2431 | /* Helper for true_dependence and canon_true_dependence. |
2432 | Checks for true dependence: X is read after store in MEM takes place. | |
9ae8ffe7 | 2433 | |
9362286d SB |
2434 | If MEM_CANONICALIZED is FALSE, then X_ADDR and MEM_ADDR should be |
2435 | NULL_RTX, and the canonical addresses of MEM and X are both computed | |
2436 | here. If MEM_CANONICALIZED, then MEM must be already canonicalized. | |
2437 | ||
2438 | If X_ADDR is non-NULL, it is used in preference of XEXP (x, 0). | |
2439 | ||
2440 | Returns 1 if there is a true dependence, 0 otherwise. */ | |
2441 | ||
2442 | static int | |
2443 | true_dependence_1 (const_rtx mem, enum machine_mode mem_mode, rtx mem_addr, | |
53d9622b | 2444 | const_rtx x, rtx x_addr, bool mem_canonicalized) |
9ae8ffe7 | 2445 | { |
49982682 | 2446 | rtx base; |
f47e08d9 | 2447 | int ret; |
9ae8ffe7 | 2448 | |
9362286d SB |
2449 | gcc_checking_assert (mem_canonicalized ? (mem_addr != NULL_RTX) |
2450 | : (mem_addr == NULL_RTX && x_addr == NULL_RTX)); | |
2451 | ||
9ae8ffe7 JL |
2452 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) |
2453 | return 1; | |
2454 | ||
c4484b8f | 2455 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
ac3768f6 | 2456 | This is used in epilogue deallocation functions, and in cselib. */ |
c4484b8f RH |
2457 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) |
2458 | return 1; | |
2459 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
2460 | return 1; | |
9cd9e512 RH |
2461 | if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER |
2462 | || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER) | |
2463 | return 1; | |
c4484b8f | 2464 | |
389fdba0 RH |
2465 | /* Read-only memory is by definition never modified, and therefore can't |
2466 | conflict with anything. We don't expect to find read-only set on MEM, | |
41806d92 | 2467 | but stupid user tricks can produce them, so don't die. */ |
389fdba0 | 2468 | if (MEM_READONLY_P (x)) |
9ae8ffe7 JL |
2469 | return 0; |
2470 | ||
5932a4d4 | 2471 | /* If we have MEMs referring to different address spaces (which can |
09e881c9 BE |
2472 | potentially overlap), we cannot easily tell from the addresses |
2473 | whether the references overlap. */ | |
2474 | if (MEM_ADDR_SPACE (mem) != MEM_ADDR_SPACE (x)) | |
2475 | return 1; | |
2476 | ||
9362286d SB |
2477 | if (! mem_addr) |
2478 | { | |
2479 | mem_addr = XEXP (mem, 0); | |
2480 | if (mem_mode == VOIDmode) | |
2481 | mem_mode = GET_MODE (mem); | |
2482 | } | |
2483 | ||
2484 | if (! x_addr) | |
2147c71c | 2485 | { |
a522de15 SB |
2486 | x_addr = XEXP (x, 0); |
2487 | if (!((GET_CODE (x_addr) == VALUE | |
2488 | && GET_CODE (mem_addr) != VALUE | |
2489 | && reg_mentioned_p (x_addr, mem_addr)) | |
2490 | || (GET_CODE (x_addr) != VALUE | |
2491 | && GET_CODE (mem_addr) == VALUE | |
2492 | && reg_mentioned_p (mem_addr, x_addr)))) | |
2493 | { | |
2494 | x_addr = get_addr (x_addr); | |
2495 | if (! mem_canonicalized) | |
2496 | mem_addr = get_addr (mem_addr); | |
2497 | } | |
2147c71c | 2498 | } |
eab5c70a | 2499 | |
55efb413 JW |
2500 | base = find_base_term (x_addr); |
2501 | if (base && (GET_CODE (base) == LABEL_REF | |
2502 | || (GET_CODE (base) == SYMBOL_REF | |
2503 | && CONSTANT_POOL_ADDRESS_P (base)))) | |
2504 | return 0; | |
2505 | ||
eab5c70a | 2506 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), mem_mode)) |
1c72c7f6 JC |
2507 | return 0; |
2508 | ||
eab5c70a | 2509 | x_addr = canon_rtx (x_addr); |
9362286d SB |
2510 | if (!mem_canonicalized) |
2511 | mem_addr = canon_rtx (mem_addr); | |
6e73e666 | 2512 | |
f47e08d9 RG |
2513 | if ((ret = memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr, |
2514 | SIZE_FOR_MODE (x), x_addr, 0)) != -1) | |
2515 | return ret; | |
2516 | ||
a95b3cc7 | 2517 | if (mems_in_disjoint_alias_sets_p (x, mem)) |
f47e08d9 RG |
2518 | return 0; |
2519 | ||
c6ea834c | 2520 | if (nonoverlapping_memrefs_p (mem, x, false)) |
0211b6ab | 2521 | return 0; |
175a7536 MM |
2522 | |
2523 | if (nonoverlapping_component_refs_p (mem, x)) | |
2524 | return 0; | |
0211b6ab | 2525 | |
55b34b5f | 2526 | return rtx_refs_may_alias_p (x, mem, true); |
a13d4ebf AM |
2527 | } |
2528 | ||
9362286d SB |
2529 | /* True dependence: X is read after store in MEM takes place. */ |
2530 | ||
2531 | int | |
53d9622b | 2532 | true_dependence (const_rtx mem, enum machine_mode mem_mode, const_rtx x) |
9362286d SB |
2533 | { |
2534 | return true_dependence_1 (mem, mem_mode, NULL_RTX, | |
53d9622b | 2535 | x, NULL_RTX, /*mem_canonicalized=*/false); |
9362286d SB |
2536 | } |
2537 | ||
a13d4ebf | 2538 | /* Canonical true dependence: X is read after store in MEM takes place. |
ca7fd9cd KH |
2539 | Variant of true_dependence which assumes MEM has already been |
2540 | canonicalized (hence we no longer do that here). | |
9362286d SB |
2541 | The mem_addr argument has been added, since true_dependence_1 computed |
2542 | this value prior to canonicalizing. */ | |
a13d4ebf AM |
2543 | |
2544 | int | |
4f588890 | 2545 | canon_true_dependence (const_rtx mem, enum machine_mode mem_mode, rtx mem_addr, |
53d9622b | 2546 | const_rtx x, rtx x_addr) |
a13d4ebf | 2547 | { |
9362286d | 2548 | return true_dependence_1 (mem, mem_mode, mem_addr, |
53d9622b | 2549 | x, x_addr, /*mem_canonicalized=*/true); |
9ae8ffe7 JL |
2550 | } |
2551 | ||
da7d8304 | 2552 | /* Returns nonzero if a write to X might alias a previous read from |
389fdba0 | 2553 | (or, if WRITEP is nonzero, a write to) MEM. */ |
9ae8ffe7 | 2554 | |
2c72b78f | 2555 | static int |
4f588890 | 2556 | write_dependence_p (const_rtx mem, const_rtx x, int writep) |
9ae8ffe7 | 2557 | { |
6e73e666 | 2558 | rtx x_addr, mem_addr; |
49982682 | 2559 | rtx base; |
f47e08d9 | 2560 | int ret; |
6e73e666 | 2561 | |
9ae8ffe7 JL |
2562 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) |
2563 | return 1; | |
2564 | ||
c4484b8f RH |
2565 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
2566 | This is used in epilogue deallocation functions. */ | |
2567 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) | |
2568 | return 1; | |
2569 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
2570 | return 1; | |
9cd9e512 RH |
2571 | if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER |
2572 | || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER) | |
2573 | return 1; | |
c4484b8f | 2574 | |
389fdba0 RH |
2575 | /* A read from read-only memory can't conflict with read-write memory. */ |
2576 | if (!writep && MEM_READONLY_P (mem)) | |
2577 | return 0; | |
55efb413 | 2578 | |
5932a4d4 | 2579 | /* If we have MEMs referring to different address spaces (which can |
09e881c9 BE |
2580 | potentially overlap), we cannot easily tell from the addresses |
2581 | whether the references overlap. */ | |
2582 | if (MEM_ADDR_SPACE (mem) != MEM_ADDR_SPACE (x)) | |
2583 | return 1; | |
2584 | ||
2147c71c L |
2585 | x_addr = XEXP (x, 0); |
2586 | mem_addr = XEXP (mem, 0); | |
2587 | if (!((GET_CODE (x_addr) == VALUE | |
2588 | && GET_CODE (mem_addr) != VALUE | |
2589 | && reg_mentioned_p (x_addr, mem_addr)) | |
2590 | || (GET_CODE (x_addr) != VALUE | |
2591 | && GET_CODE (mem_addr) == VALUE | |
2592 | && reg_mentioned_p (mem_addr, x_addr)))) | |
2593 | { | |
2594 | x_addr = get_addr (x_addr); | |
2595 | mem_addr = get_addr (mem_addr); | |
2596 | } | |
55efb413 | 2597 | |
49982682 JW |
2598 | if (! writep) |
2599 | { | |
55efb413 | 2600 | base = find_base_term (mem_addr); |
49982682 JW |
2601 | if (base && (GET_CODE (base) == LABEL_REF |
2602 | || (GET_CODE (base) == SYMBOL_REF | |
2603 | && CONSTANT_POOL_ADDRESS_P (base)))) | |
2604 | return 0; | |
2605 | } | |
2606 | ||
eab5c70a BS |
2607 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), |
2608 | GET_MODE (mem))) | |
41472af8 MM |
2609 | return 0; |
2610 | ||
eab5c70a BS |
2611 | x_addr = canon_rtx (x_addr); |
2612 | mem_addr = canon_rtx (mem_addr); | |
6e73e666 | 2613 | |
f47e08d9 RG |
2614 | if ((ret = memrefs_conflict_p (SIZE_FOR_MODE (mem), mem_addr, |
2615 | SIZE_FOR_MODE (x), x_addr, 0)) != -1) | |
2616 | return ret; | |
2617 | ||
c6ea834c | 2618 | if (nonoverlapping_memrefs_p (x, mem, false)) |
c6df88cb MM |
2619 | return 0; |
2620 | ||
55b34b5f | 2621 | return rtx_refs_may_alias_p (x, mem, false); |
c6df88cb MM |
2622 | } |
2623 | ||
2624 | /* Anti dependence: X is written after read in MEM takes place. */ | |
2625 | ||
2626 | int | |
4f588890 | 2627 | anti_dependence (const_rtx mem, const_rtx x) |
c6df88cb | 2628 | { |
389fdba0 | 2629 | return write_dependence_p (mem, x, /*writep=*/0); |
9ae8ffe7 JL |
2630 | } |
2631 | ||
2632 | /* Output dependence: X is written after store in MEM takes place. */ | |
2633 | ||
2634 | int | |
4f588890 | 2635 | output_dependence (const_rtx mem, const_rtx x) |
9ae8ffe7 | 2636 | { |
389fdba0 | 2637 | return write_dependence_p (mem, x, /*writep=*/1); |
9ae8ffe7 | 2638 | } |
c14b9960 | 2639 | \f |
6e73e666 | 2640 | |
c6ea834c BM |
2641 | |
2642 | /* Check whether X may be aliased with MEM. Don't do offset-based | |
2643 | memory disambiguation & TBAA. */ | |
2644 | int | |
2645 | may_alias_p (const_rtx mem, const_rtx x) | |
2646 | { | |
2647 | rtx x_addr, mem_addr; | |
c6ea834c BM |
2648 | |
2649 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) | |
2650 | return 1; | |
2651 | ||
a95b3cc7 RG |
2652 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
2653 | This is used in epilogue deallocation functions. */ | |
2654 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) | |
2655 | return 1; | |
2656 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
c6ea834c | 2657 | return 1; |
c6ea834c BM |
2658 | if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER |
2659 | || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER) | |
2660 | return 1; | |
2661 | ||
2662 | /* Read-only memory is by definition never modified, and therefore can't | |
2663 | conflict with anything. We don't expect to find read-only set on MEM, | |
2664 | but stupid user tricks can produce them, so don't die. */ | |
2665 | if (MEM_READONLY_P (x)) | |
2666 | return 0; | |
2667 | ||
5932a4d4 | 2668 | /* If we have MEMs referring to different address spaces (which can |
c6ea834c BM |
2669 | potentially overlap), we cannot easily tell from the addresses |
2670 | whether the references overlap. */ | |
2671 | if (MEM_ADDR_SPACE (mem) != MEM_ADDR_SPACE (x)) | |
2672 | return 1; | |
2673 | ||
2674 | x_addr = XEXP (x, 0); | |
2675 | mem_addr = XEXP (mem, 0); | |
2676 | if (!((GET_CODE (x_addr) == VALUE | |
2677 | && GET_CODE (mem_addr) != VALUE | |
2678 | && reg_mentioned_p (x_addr, mem_addr)) | |
2679 | || (GET_CODE (x_addr) != VALUE | |
2680 | && GET_CODE (mem_addr) == VALUE | |
2681 | && reg_mentioned_p (mem_addr, x_addr)))) | |
2682 | { | |
2683 | x_addr = get_addr (x_addr); | |
2684 | mem_addr = get_addr (mem_addr); | |
2685 | } | |
2686 | ||
2687 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), GET_MODE (mem_addr))) | |
2688 | return 0; | |
2689 | ||
2690 | x_addr = canon_rtx (x_addr); | |
2691 | mem_addr = canon_rtx (mem_addr); | |
2692 | ||
2693 | if (nonoverlapping_memrefs_p (mem, x, true)) | |
2694 | return 0; | |
2695 | ||
c6ea834c BM |
2696 | /* TBAA not valid for loop_invarint */ |
2697 | return rtx_refs_may_alias_p (x, mem, false); | |
2698 | } | |
2699 | ||
6e73e666 | 2700 | void |
b5deb7b6 | 2701 | init_alias_target (void) |
6e73e666 | 2702 | { |
b3694847 | 2703 | int i; |
6e73e666 | 2704 | |
9fc37b2b RS |
2705 | if (!arg_base_value) |
2706 | arg_base_value = gen_rtx_ADDRESS (VOIDmode, 0); | |
2707 | ||
b5deb7b6 SL |
2708 | memset (static_reg_base_value, 0, sizeof static_reg_base_value); |
2709 | ||
6e73e666 JC |
2710 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) |
2711 | /* Check whether this register can hold an incoming pointer | |
2712 | argument. FUNCTION_ARG_REGNO_P tests outgoing register | |
ec5c56db | 2713 | numbers, so translate if necessary due to register windows. */ |
6e73e666 JC |
2714 | if (FUNCTION_ARG_REGNO_P (OUTGOING_REGNO (i)) |
2715 | && HARD_REGNO_MODE_OK (i, Pmode)) | |
9fc37b2b RS |
2716 | static_reg_base_value[i] = arg_base_value; |
2717 | ||
757e8ba2 JJ |
2718 | static_reg_base_value[STACK_POINTER_REGNUM] |
2719 | = unique_base_value (UNIQUE_BASE_VALUE_SP); | |
2720 | static_reg_base_value[ARG_POINTER_REGNUM] | |
2721 | = unique_base_value (UNIQUE_BASE_VALUE_ARGP); | |
2722 | static_reg_base_value[FRAME_POINTER_REGNUM] | |
2723 | = unique_base_value (UNIQUE_BASE_VALUE_FP); | |
e3339d0f | 2724 | #if !HARD_FRAME_POINTER_IS_FRAME_POINTER |
757e8ba2 JJ |
2725 | static_reg_base_value[HARD_FRAME_POINTER_REGNUM] |
2726 | = unique_base_value (UNIQUE_BASE_VALUE_HFP); | |
bf1660a6 JL |
2727 | #endif |
2728 | } | |
2729 | ||
7b52eede JH |
2730 | /* Set MEMORY_MODIFIED when X modifies DATA (that is assumed |
2731 | to be memory reference. */ | |
2732 | static bool memory_modified; | |
2733 | static void | |
aa317c97 | 2734 | memory_modified_1 (rtx x, const_rtx pat ATTRIBUTE_UNUSED, void *data) |
7b52eede | 2735 | { |
3c0cb5de | 2736 | if (MEM_P (x)) |
7b52eede | 2737 | { |
9678086d | 2738 | if (anti_dependence (x, (const_rtx)data) || output_dependence (x, (const_rtx)data)) |
7b52eede JH |
2739 | memory_modified = true; |
2740 | } | |
2741 | } | |
2742 | ||
2743 | ||
2744 | /* Return true when INSN possibly modify memory contents of MEM | |
454ff5cb | 2745 | (i.e. address can be modified). */ |
7b52eede | 2746 | bool |
9678086d | 2747 | memory_modified_in_insn_p (const_rtx mem, const_rtx insn) |
7b52eede JH |
2748 | { |
2749 | if (!INSN_P (insn)) | |
2750 | return false; | |
2751 | memory_modified = false; | |
aa317c97 | 2752 | note_stores (PATTERN (insn), memory_modified_1, CONST_CAST_RTX(mem)); |
7b52eede JH |
2753 | return memory_modified; |
2754 | } | |
2755 | ||
c13e8210 MM |
2756 | /* Initialize the aliasing machinery. Initialize the REG_KNOWN_VALUE |
2757 | array. */ | |
2758 | ||
9ae8ffe7 | 2759 | void |
4682ae04 | 2760 | init_alias_analysis (void) |
9ae8ffe7 | 2761 | { |
c582d54a | 2762 | unsigned int maxreg = max_reg_num (); |
ea64ef27 | 2763 | int changed, pass; |
b3694847 SS |
2764 | int i; |
2765 | unsigned int ui; | |
9ff3c7ca | 2766 | rtx insn, val; |
9ae8ffe7 | 2767 | |
0d446150 JH |
2768 | timevar_push (TV_ALIAS_ANALYSIS); |
2769 | ||
9ff3c7ca SB |
2770 | reg_known_value = VEC_alloc (rtx, gc, maxreg - FIRST_PSEUDO_REGISTER); |
2771 | reg_known_equiv_p = sbitmap_alloc (maxreg - FIRST_PSEUDO_REGISTER); | |
9ae8ffe7 | 2772 | |
08c79682 | 2773 | /* If we have memory allocated from the previous run, use it. */ |
c582d54a | 2774 | if (old_reg_base_value) |
08c79682 KH |
2775 | reg_base_value = old_reg_base_value; |
2776 | ||
2777 | if (reg_base_value) | |
2778 | VEC_truncate (rtx, reg_base_value, 0); | |
2779 | ||
a590ac65 | 2780 | VEC_safe_grow_cleared (rtx, gc, reg_base_value, maxreg); |
ac606739 | 2781 | |
5ed6ace5 MD |
2782 | new_reg_base_value = XNEWVEC (rtx, maxreg); |
2783 | reg_seen = XNEWVEC (char, maxreg); | |
ec907dd8 JL |
2784 | |
2785 | /* The basic idea is that each pass through this loop will use the | |
2786 | "constant" information from the previous pass to propagate alias | |
2787 | information through another level of assignments. | |
2788 | ||
2789 | This could get expensive if the assignment chains are long. Maybe | |
2790 | we should throttle the number of iterations, possibly based on | |
6e73e666 | 2791 | the optimization level or flag_expensive_optimizations. |
ec907dd8 JL |
2792 | |
2793 | We could propagate more information in the first pass by making use | |
6fb5fa3c | 2794 | of DF_REG_DEF_COUNT to determine immediately that the alias information |
ea64ef27 JL |
2795 | for a pseudo is "constant". |
2796 | ||
2797 | A program with an uninitialized variable can cause an infinite loop | |
2798 | here. Instead of doing a full dataflow analysis to detect such problems | |
2799 | we just cap the number of iterations for the loop. | |
2800 | ||
2801 | The state of the arrays for the set chain in question does not matter | |
2802 | since the program has undefined behavior. */ | |
6e73e666 | 2803 | |
ea64ef27 | 2804 | pass = 0; |
6e73e666 | 2805 | do |
ec907dd8 JL |
2806 | { |
2807 | /* Assume nothing will change this iteration of the loop. */ | |
2808 | changed = 0; | |
2809 | ||
ec907dd8 | 2810 | /* We want to assign the same IDs each iteration of this loop, so |
9fc37b2b RS |
2811 | start counting from one each iteration of the loop. */ |
2812 | unique_id = 1; | |
ec907dd8 | 2813 | |
f5143c46 | 2814 | /* We're at the start of the function each iteration through the |
ec907dd8 | 2815 | loop, so we're copying arguments. */ |
83bbd9b6 | 2816 | copying_arguments = true; |
9ae8ffe7 | 2817 | |
6e73e666 | 2818 | /* Wipe the potential alias information clean for this pass. */ |
c582d54a | 2819 | memset (new_reg_base_value, 0, maxreg * sizeof (rtx)); |
8072f69c | 2820 | |
6e73e666 | 2821 | /* Wipe the reg_seen array clean. */ |
c582d54a | 2822 | memset (reg_seen, 0, maxreg); |
9ae8ffe7 | 2823 | |
6e73e666 JC |
2824 | /* Mark all hard registers which may contain an address. |
2825 | The stack, frame and argument pointers may contain an address. | |
2826 | An argument register which can hold a Pmode value may contain | |
2827 | an address even if it is not in BASE_REGS. | |
8072f69c | 2828 | |
6e73e666 JC |
2829 | The address expression is VOIDmode for an argument and |
2830 | Pmode for other registers. */ | |
2831 | ||
7f243674 JL |
2832 | memcpy (new_reg_base_value, static_reg_base_value, |
2833 | FIRST_PSEUDO_REGISTER * sizeof (rtx)); | |
6e73e666 | 2834 | |
ec907dd8 JL |
2835 | /* Walk the insns adding values to the new_reg_base_value array. */ |
2836 | for (insn = get_insns (); insn; insn = NEXT_INSN (insn)) | |
9ae8ffe7 | 2837 | { |
2c3c49de | 2838 | if (INSN_P (insn)) |
ec907dd8 | 2839 | { |
6e73e666 | 2840 | rtx note, set; |
efc9bd41 RK |
2841 | |
2842 | #if defined (HAVE_prologue) || defined (HAVE_epilogue) | |
f5143c46 | 2843 | /* The prologue/epilogue insns are not threaded onto the |
657959ca JL |
2844 | insn chain until after reload has completed. Thus, |
2845 | there is no sense wasting time checking if INSN is in | |
2846 | the prologue/epilogue until after reload has completed. */ | |
2847 | if (reload_completed | |
2848 | && prologue_epilogue_contains (insn)) | |
efc9bd41 RK |
2849 | continue; |
2850 | #endif | |
2851 | ||
ec907dd8 | 2852 | /* If this insn has a noalias note, process it, Otherwise, |
c22cacf3 MS |
2853 | scan for sets. A simple set will have no side effects |
2854 | which could change the base value of any other register. */ | |
6e73e666 | 2855 | |
ec907dd8 | 2856 | if (GET_CODE (PATTERN (insn)) == SET |
efc9bd41 RK |
2857 | && REG_NOTES (insn) != 0 |
2858 | && find_reg_note (insn, REG_NOALIAS, NULL_RTX)) | |
84832317 | 2859 | record_set (SET_DEST (PATTERN (insn)), NULL_RTX, NULL); |
ec907dd8 | 2860 | else |
84832317 | 2861 | note_stores (PATTERN (insn), record_set, NULL); |
6e73e666 JC |
2862 | |
2863 | set = single_set (insn); | |
2864 | ||
2865 | if (set != 0 | |
f8cfc6aa | 2866 | && REG_P (SET_DEST (set)) |
fb6754f0 | 2867 | && REGNO (SET_DEST (set)) >= FIRST_PSEUDO_REGISTER) |
6e73e666 | 2868 | { |
fb6754f0 | 2869 | unsigned int regno = REGNO (SET_DEST (set)); |
713f41f9 | 2870 | rtx src = SET_SRC (set); |
bb1acb3e | 2871 | rtx t; |
713f41f9 | 2872 | |
a31830a7 SB |
2873 | note = find_reg_equal_equiv_note (insn); |
2874 | if (note && REG_NOTE_KIND (note) == REG_EQUAL | |
6fb5fa3c | 2875 | && DF_REG_DEF_COUNT (regno) != 1) |
a31830a7 SB |
2876 | note = NULL_RTX; |
2877 | ||
2878 | if (note != NULL_RTX | |
713f41f9 | 2879 | && GET_CODE (XEXP (note, 0)) != EXPR_LIST |
bb2cf916 | 2880 | && ! rtx_varies_p (XEXP (note, 0), 1) |
bb1acb3e RH |
2881 | && ! reg_overlap_mentioned_p (SET_DEST (set), |
2882 | XEXP (note, 0))) | |
713f41f9 | 2883 | { |
bb1acb3e RH |
2884 | set_reg_known_value (regno, XEXP (note, 0)); |
2885 | set_reg_known_equiv_p (regno, | |
2886 | REG_NOTE_KIND (note) == REG_EQUIV); | |
713f41f9 | 2887 | } |
6fb5fa3c | 2888 | else if (DF_REG_DEF_COUNT (regno) == 1 |
713f41f9 | 2889 | && GET_CODE (src) == PLUS |
f8cfc6aa | 2890 | && REG_P (XEXP (src, 0)) |
bb1acb3e | 2891 | && (t = get_reg_known_value (REGNO (XEXP (src, 0)))) |
481683e1 | 2892 | && CONST_INT_P (XEXP (src, 1))) |
713f41f9 | 2893 | { |
0a81f074 RS |
2894 | t = plus_constant (GET_MODE (src), t, |
2895 | INTVAL (XEXP (src, 1))); | |
bb1acb3e | 2896 | set_reg_known_value (regno, t); |
9ff3c7ca | 2897 | set_reg_known_equiv_p (regno, false); |
713f41f9 | 2898 | } |
6fb5fa3c | 2899 | else if (DF_REG_DEF_COUNT (regno) == 1 |
713f41f9 BS |
2900 | && ! rtx_varies_p (src, 1)) |
2901 | { | |
bb1acb3e | 2902 | set_reg_known_value (regno, src); |
9ff3c7ca | 2903 | set_reg_known_equiv_p (regno, false); |
713f41f9 | 2904 | } |
6e73e666 | 2905 | } |
ec907dd8 | 2906 | } |
4b4bf941 | 2907 | else if (NOTE_P (insn) |
a38e7aa5 | 2908 | && NOTE_KIND (insn) == NOTE_INSN_FUNCTION_BEG) |
83bbd9b6 | 2909 | copying_arguments = false; |
6e73e666 | 2910 | } |
ec907dd8 | 2911 | |
6e73e666 | 2912 | /* Now propagate values from new_reg_base_value to reg_base_value. */ |
62e5bf5d | 2913 | gcc_assert (maxreg == (unsigned int) max_reg_num ()); |
c22cacf3 | 2914 | |
c582d54a | 2915 | for (ui = 0; ui < maxreg; ui++) |
6e73e666 | 2916 | { |
e51712db | 2917 | if (new_reg_base_value[ui] |
08c79682 | 2918 | && new_reg_base_value[ui] != VEC_index (rtx, reg_base_value, ui) |
c582d54a | 2919 | && ! rtx_equal_p (new_reg_base_value[ui], |
08c79682 | 2920 | VEC_index (rtx, reg_base_value, ui))) |
ec907dd8 | 2921 | { |
08c79682 | 2922 | VEC_replace (rtx, reg_base_value, ui, new_reg_base_value[ui]); |
6e73e666 | 2923 | changed = 1; |
ec907dd8 | 2924 | } |
9ae8ffe7 | 2925 | } |
9ae8ffe7 | 2926 | } |
6e73e666 | 2927 | while (changed && ++pass < MAX_ALIAS_LOOP_PASSES); |
9ae8ffe7 JL |
2928 | |
2929 | /* Fill in the remaining entries. */ | |
9ff3c7ca SB |
2930 | FOR_EACH_VEC_ELT (rtx, reg_known_value, i, val) |
2931 | { | |
2932 | int regno = i + FIRST_PSEUDO_REGISTER; | |
2933 | if (! val) | |
2934 | set_reg_known_value (regno, regno_reg_rtx[regno]); | |
2935 | } | |
9ae8ffe7 | 2936 | |
e05e2395 MM |
2937 | /* Clean up. */ |
2938 | free (new_reg_base_value); | |
ec907dd8 | 2939 | new_reg_base_value = 0; |
e05e2395 | 2940 | free (reg_seen); |
9ae8ffe7 | 2941 | reg_seen = 0; |
0d446150 | 2942 | timevar_pop (TV_ALIAS_ANALYSIS); |
9ae8ffe7 JL |
2943 | } |
2944 | ||
61630b27 JJ |
2945 | /* Equate REG_BASE_VALUE (reg1) to REG_BASE_VALUE (reg2). |
2946 | Special API for var-tracking pass purposes. */ | |
2947 | ||
2948 | void | |
2949 | vt_equate_reg_base_value (const_rtx reg1, const_rtx reg2) | |
2950 | { | |
2951 | VEC_replace (rtx, reg_base_value, REGNO (reg1), REG_BASE_VALUE (reg2)); | |
2952 | } | |
2953 | ||
9ae8ffe7 | 2954 | void |
4682ae04 | 2955 | end_alias_analysis (void) |
9ae8ffe7 | 2956 | { |
c582d54a | 2957 | old_reg_base_value = reg_base_value; |
9ff3c7ca SB |
2958 | VEC_free (rtx, gc, reg_known_value); |
2959 | sbitmap_free (reg_known_equiv_p); | |
9ae8ffe7 | 2960 | } |
e2500fed GK |
2961 | |
2962 | #include "gt-alias.h" |