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9ae8ffe7 | 1 | /* Alias analysis for GNU C |
62e5bf5d | 2 | Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, |
66647d44 | 3 | 2007, 2008, 2009 Free Software Foundation, Inc. |
9ae8ffe7 JL |
4 | Contributed by John Carr (jfc@mit.edu). |
5 | ||
1322177d | 6 | This file is part of GCC. |
9ae8ffe7 | 7 | |
1322177d LB |
8 | GCC is free software; you can redistribute it and/or modify it under |
9 | the terms of the GNU General Public License as published by the Free | |
9dcd6f09 | 10 | Software Foundation; either version 3, or (at your option) any later |
1322177d | 11 | version. |
9ae8ffe7 | 12 | |
1322177d LB |
13 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY |
14 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
15 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
16 | for more details. | |
9ae8ffe7 JL |
17 | |
18 | You should have received a copy of the GNU General Public License | |
9dcd6f09 NC |
19 | along with GCC; see the file COPYING3. If not see |
20 | <http://www.gnu.org/licenses/>. */ | |
9ae8ffe7 JL |
21 | |
22 | #include "config.h" | |
670ee920 | 23 | #include "system.h" |
4977bab6 ZW |
24 | #include "coretypes.h" |
25 | #include "tm.h" | |
9ae8ffe7 | 26 | #include "rtl.h" |
7790df19 | 27 | #include "tree.h" |
6baf1cc8 | 28 | #include "tm_p.h" |
49ad7cfa | 29 | #include "function.h" |
78528714 JQ |
30 | #include "alias.h" |
31 | #include "emit-rtl.h" | |
9ae8ffe7 JL |
32 | #include "regs.h" |
33 | #include "hard-reg-set.h" | |
e004f2f7 | 34 | #include "basic-block.h" |
9ae8ffe7 | 35 | #include "flags.h" |
264fac34 | 36 | #include "output.h" |
2e107e9e | 37 | #include "toplev.h" |
eab5c70a | 38 | #include "cselib.h" |
3932261a | 39 | #include "splay-tree.h" |
ac606739 | 40 | #include "ggc.h" |
d23c55c2 | 41 | #include "langhooks.h" |
0d446150 | 42 | #include "timevar.h" |
ab780373 | 43 | #include "target.h" |
b255a036 | 44 | #include "cgraph.h" |
9ddb66ca | 45 | #include "varray.h" |
ef330312 | 46 | #include "tree-pass.h" |
ea900239 | 47 | #include "ipa-type-escape.h" |
6fb5fa3c | 48 | #include "df.h" |
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 | |
78 | a store thru a pointer to an X can overwrite any field that is | |
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 AJ |
157 | static int insert_subset_children (splay_tree_node, void*); |
158 | static tree find_base_decl (tree); | |
4862826d | 159 | static alias_set_entry get_alias_set_entry (alias_set_type); |
4f588890 KG |
160 | static const_rtx fixed_scalar_and_varying_struct_p (const_rtx, const_rtx, rtx, rtx, |
161 | bool (*) (const_rtx, bool)); | |
162 | static int aliases_everything_p (const_rtx); | |
163 | static bool nonoverlapping_component_refs_p (const_tree, const_tree); | |
4682ae04 AJ |
164 | static tree decl_for_component_ref (tree); |
165 | static rtx adjust_offset_for_component_ref (tree, rtx); | |
4f588890 | 166 | static int write_dependence_p (const_rtx, const_rtx, int); |
4682ae04 | 167 | |
aa317c97 | 168 | static void memory_modified_1 (rtx, const_rtx, void *); |
9ae8ffe7 JL |
169 | |
170 | /* Set up all info needed to perform alias analysis on memory references. */ | |
171 | ||
d4b60170 | 172 | /* Returns the size in bytes of the mode of X. */ |
9ae8ffe7 JL |
173 | #define SIZE_FOR_MODE(X) (GET_MODE_SIZE (GET_MODE (X))) |
174 | ||
41472af8 | 175 | /* Returns nonzero if MEM1 and MEM2 do not alias because they are in |
264fac34 MM |
176 | different alias sets. We ignore alias sets in functions making use |
177 | of variable arguments because the va_arg macros on some systems are | |
178 | not legal ANSI C. */ | |
179 | #define DIFFERENT_ALIAS_SETS_P(MEM1, MEM2) \ | |
3932261a | 180 | mems_in_disjoint_alias_sets_p (MEM1, MEM2) |
41472af8 | 181 | |
ea64ef27 | 182 | /* Cap the number of passes we make over the insns propagating alias |
ac3d9668 | 183 | information through set chains. 10 is a completely arbitrary choice. */ |
ea64ef27 | 184 | #define MAX_ALIAS_LOOP_PASSES 10 |
ca7fd9cd | 185 | |
9ae8ffe7 JL |
186 | /* reg_base_value[N] gives an address to which register N is related. |
187 | If all sets after the first add or subtract to the current value | |
188 | or otherwise modify it so it does not point to a different top level | |
189 | object, reg_base_value[N] is equal to the address part of the source | |
2a2c8203 JC |
190 | of the first set. |
191 | ||
192 | A base address can be an ADDRESS, SYMBOL_REF, or LABEL_REF. ADDRESS | |
193 | expressions represent certain special values: function arguments and | |
ca7fd9cd | 194 | the stack, frame, and argument pointers. |
b3b5ad95 JL |
195 | |
196 | The contents of an ADDRESS is not normally used, the mode of the | |
197 | ADDRESS determines whether the ADDRESS is a function argument or some | |
198 | other special value. Pointer equality, not rtx_equal_p, determines whether | |
199 | two ADDRESS expressions refer to the same base address. | |
200 | ||
201 | The only use of the contents of an ADDRESS is for determining if the | |
202 | current function performs nonlocal memory memory references for the | |
203 | purposes of marking the function as a constant function. */ | |
2a2c8203 | 204 | |
08c79682 | 205 | static GTY(()) VEC(rtx,gc) *reg_base_value; |
ac606739 | 206 | static rtx *new_reg_base_value; |
c582d54a JH |
207 | |
208 | /* We preserve the copy of old array around to avoid amount of garbage | |
209 | produced. About 8% of garbage produced were attributed to this | |
210 | array. */ | |
08c79682 | 211 | static GTY((deletable)) VEC(rtx,gc) *old_reg_base_value; |
d4b60170 | 212 | |
bf1660a6 JL |
213 | /* Static hunks of RTL used by the aliasing code; these are initialized |
214 | once per function to avoid unnecessary RTL allocations. */ | |
215 | static GTY (()) rtx static_reg_base_value[FIRST_PSEUDO_REGISTER]; | |
216 | ||
08c79682 KH |
217 | #define REG_BASE_VALUE(X) \ |
218 | (REGNO (X) < VEC_length (rtx, reg_base_value) \ | |
219 | ? VEC_index (rtx, reg_base_value, REGNO (X)) : 0) | |
9ae8ffe7 | 220 | |
c13e8210 | 221 | /* Vector indexed by N giving the initial (unchanging) value known for |
bb1acb3e RH |
222 | pseudo-register N. This array is initialized in init_alias_analysis, |
223 | and does not change until end_alias_analysis is called. */ | |
224 | static GTY((length("reg_known_value_size"))) rtx *reg_known_value; | |
9ae8ffe7 JL |
225 | |
226 | /* Indicates number of valid entries in reg_known_value. */ | |
bb1acb3e | 227 | static GTY(()) unsigned int reg_known_value_size; |
9ae8ffe7 JL |
228 | |
229 | /* Vector recording for each reg_known_value whether it is due to a | |
230 | REG_EQUIV note. Future passes (viz., reload) may replace the | |
231 | pseudo with the equivalent expression and so we account for the | |
ac3d9668 RK |
232 | dependences that would be introduced if that happens. |
233 | ||
234 | The REG_EQUIV notes created in assign_parms may mention the arg | |
235 | pointer, and there are explicit insns in the RTL that modify the | |
236 | arg pointer. Thus we must ensure that such insns don't get | |
237 | scheduled across each other because that would invalidate the | |
238 | REG_EQUIV notes. One could argue that the REG_EQUIV notes are | |
239 | wrong, but solving the problem in the scheduler will likely give | |
240 | better code, so we do it here. */ | |
bb1acb3e | 241 | static bool *reg_known_equiv_p; |
9ae8ffe7 | 242 | |
2a2c8203 JC |
243 | /* True when scanning insns from the start of the rtl to the |
244 | NOTE_INSN_FUNCTION_BEG note. */ | |
83bbd9b6 | 245 | static bool copying_arguments; |
9ae8ffe7 | 246 | |
1a5640b4 KH |
247 | DEF_VEC_P(alias_set_entry); |
248 | DEF_VEC_ALLOC_P(alias_set_entry,gc); | |
249 | ||
3932261a | 250 | /* The splay-tree used to store the various alias set entries. */ |
1a5640b4 | 251 | static GTY (()) VEC(alias_set_entry,gc) *alias_sets; |
ac3d9668 | 252 | \f |
3932261a MM |
253 | /* Returns a pointer to the alias set entry for ALIAS_SET, if there is |
254 | such an entry, or NULL otherwise. */ | |
255 | ||
9ddb66ca | 256 | static inline alias_set_entry |
4862826d | 257 | get_alias_set_entry (alias_set_type alias_set) |
3932261a | 258 | { |
1a5640b4 | 259 | return VEC_index (alias_set_entry, alias_sets, alias_set); |
3932261a MM |
260 | } |
261 | ||
ac3d9668 RK |
262 | /* Returns nonzero if the alias sets for MEM1 and MEM2 are such that |
263 | the two MEMs cannot alias each other. */ | |
3932261a | 264 | |
9ddb66ca | 265 | static inline int |
4f588890 | 266 | mems_in_disjoint_alias_sets_p (const_rtx mem1, const_rtx mem2) |
3932261a | 267 | { |
3932261a MM |
268 | /* Perform a basic sanity check. Namely, that there are no alias sets |
269 | if we're not using strict aliasing. This helps to catch bugs | |
270 | whereby someone uses PUT_CODE, but doesn't clear MEM_ALIAS_SET, or | |
271 | where a MEM is allocated in some way other than by the use of | |
272 | gen_rtx_MEM, and the MEM_ALIAS_SET is not cleared. If we begin to | |
273 | use alias sets to indicate that spilled registers cannot alias each | |
274 | other, we might need to remove this check. */ | |
298e6adc NS |
275 | gcc_assert (flag_strict_aliasing |
276 | || (!MEM_ALIAS_SET (mem1) && !MEM_ALIAS_SET (mem2))); | |
3932261a | 277 | |
1da68f56 RK |
278 | return ! alias_sets_conflict_p (MEM_ALIAS_SET (mem1), MEM_ALIAS_SET (mem2)); |
279 | } | |
3932261a | 280 | |
1da68f56 RK |
281 | /* Insert the NODE into the splay tree given by DATA. Used by |
282 | record_alias_subset via splay_tree_foreach. */ | |
283 | ||
284 | static int | |
4682ae04 | 285 | insert_subset_children (splay_tree_node node, void *data) |
1da68f56 RK |
286 | { |
287 | splay_tree_insert ((splay_tree) data, node->key, node->value); | |
288 | ||
289 | return 0; | |
290 | } | |
291 | ||
c58936b6 DB |
292 | /* Return true if the first alias set is a subset of the second. */ |
293 | ||
294 | bool | |
4862826d | 295 | alias_set_subset_of (alias_set_type set1, alias_set_type set2) |
c58936b6 DB |
296 | { |
297 | alias_set_entry ase; | |
298 | ||
299 | /* Everything is a subset of the "aliases everything" set. */ | |
300 | if (set2 == 0) | |
301 | return true; | |
302 | ||
303 | /* Otherwise, check if set1 is a subset of set2. */ | |
304 | ase = get_alias_set_entry (set2); | |
305 | if (ase != 0 | |
a7a512be RG |
306 | && ((ase->has_zero_child && set1 == 0) |
307 | || splay_tree_lookup (ase->children, | |
308 | (splay_tree_key) set1))) | |
c58936b6 DB |
309 | return true; |
310 | return false; | |
311 | } | |
312 | ||
1da68f56 RK |
313 | /* Return 1 if the two specified alias sets may conflict. */ |
314 | ||
315 | int | |
4862826d | 316 | alias_sets_conflict_p (alias_set_type set1, alias_set_type set2) |
1da68f56 RK |
317 | { |
318 | alias_set_entry ase; | |
319 | ||
836f7794 EB |
320 | /* The easy case. */ |
321 | if (alias_sets_must_conflict_p (set1, set2)) | |
1da68f56 | 322 | return 1; |
3932261a | 323 | |
3bdf5ad1 | 324 | /* See if the first alias set is a subset of the second. */ |
1da68f56 | 325 | ase = get_alias_set_entry (set1); |
2bf105ab RK |
326 | if (ase != 0 |
327 | && (ase->has_zero_child | |
328 | || splay_tree_lookup (ase->children, | |
1da68f56 RK |
329 | (splay_tree_key) set2))) |
330 | return 1; | |
3932261a MM |
331 | |
332 | /* Now do the same, but with the alias sets reversed. */ | |
1da68f56 | 333 | ase = get_alias_set_entry (set2); |
2bf105ab RK |
334 | if (ase != 0 |
335 | && (ase->has_zero_child | |
336 | || splay_tree_lookup (ase->children, | |
1da68f56 RK |
337 | (splay_tree_key) set1))) |
338 | return 1; | |
3932261a | 339 | |
1da68f56 | 340 | /* The two alias sets are distinct and neither one is the |
836f7794 | 341 | child of the other. Therefore, they cannot conflict. */ |
1da68f56 | 342 | return 0; |
3932261a | 343 | } |
5399d643 | 344 | |
71a6fe66 BM |
345 | static int |
346 | walk_mems_2 (rtx *x, rtx mem) | |
347 | { | |
348 | if (MEM_P (*x)) | |
349 | { | |
350 | if (alias_sets_conflict_p (MEM_ALIAS_SET(*x), MEM_ALIAS_SET(mem))) | |
351 | return 1; | |
352 | ||
353 | return -1; | |
354 | } | |
355 | return 0; | |
356 | } | |
357 | ||
358 | static int | |
359 | walk_mems_1 (rtx *x, rtx *pat) | |
360 | { | |
361 | if (MEM_P (*x)) | |
362 | { | |
363 | /* Visit all MEMs in *PAT and check indepedence. */ | |
364 | if (for_each_rtx (pat, (rtx_function) walk_mems_2, *x)) | |
365 | /* Indicate that dependence was determined and stop traversal. */ | |
366 | return 1; | |
367 | ||
368 | return -1; | |
369 | } | |
370 | return 0; | |
371 | } | |
372 | ||
373 | /* Return 1 if two specified instructions have mem expr with conflict alias sets*/ | |
374 | bool | |
375 | insn_alias_sets_conflict_p (rtx insn1, rtx insn2) | |
376 | { | |
377 | /* For each pair of MEMs in INSN1 and INSN2 check their independence. */ | |
378 | return for_each_rtx (&PATTERN (insn1), (rtx_function) walk_mems_1, | |
379 | &PATTERN (insn2)); | |
380 | } | |
381 | ||
836f7794 | 382 | /* Return 1 if the two specified alias sets will always conflict. */ |
5399d643 JW |
383 | |
384 | int | |
4862826d | 385 | alias_sets_must_conflict_p (alias_set_type set1, alias_set_type set2) |
5399d643 JW |
386 | { |
387 | if (set1 == 0 || set2 == 0 || set1 == set2) | |
388 | return 1; | |
389 | ||
390 | return 0; | |
391 | } | |
392 | ||
1da68f56 RK |
393 | /* Return 1 if any MEM object of type T1 will always conflict (using the |
394 | dependency routines in this file) with any MEM object of type T2. | |
395 | This is used when allocating temporary storage. If T1 and/or T2 are | |
396 | NULL_TREE, it means we know nothing about the storage. */ | |
397 | ||
398 | int | |
4682ae04 | 399 | objects_must_conflict_p (tree t1, tree t2) |
1da68f56 | 400 | { |
4862826d | 401 | alias_set_type set1, set2; |
82d610ec | 402 | |
e8ea2809 RK |
403 | /* If neither has a type specified, we don't know if they'll conflict |
404 | because we may be using them to store objects of various types, for | |
405 | example the argument and local variables areas of inlined functions. */ | |
981a4c34 | 406 | if (t1 == 0 && t2 == 0) |
e8ea2809 RK |
407 | return 0; |
408 | ||
1da68f56 RK |
409 | /* If they are the same type, they must conflict. */ |
410 | if (t1 == t2 | |
411 | /* Likewise if both are volatile. */ | |
412 | || (t1 != 0 && TYPE_VOLATILE (t1) && t2 != 0 && TYPE_VOLATILE (t2))) | |
413 | return 1; | |
414 | ||
82d610ec RK |
415 | set1 = t1 ? get_alias_set (t1) : 0; |
416 | set2 = t2 ? get_alias_set (t2) : 0; | |
1da68f56 | 417 | |
836f7794 EB |
418 | /* We can't use alias_sets_conflict_p because we must make sure |
419 | that every subtype of t1 will conflict with every subtype of | |
82d610ec RK |
420 | t2 for which a pair of subobjects of these respective subtypes |
421 | overlaps on the stack. */ | |
836f7794 | 422 | return alias_sets_must_conflict_p (set1, set2); |
1da68f56 RK |
423 | } |
424 | \f | |
3bdf5ad1 RK |
425 | /* T is an expression with pointer type. Find the DECL on which this |
426 | expression is based. (For example, in `a[i]' this would be `a'.) | |
427 | If there is no such DECL, or a unique decl cannot be determined, | |
f5143c46 | 428 | NULL_TREE is returned. */ |
3bdf5ad1 RK |
429 | |
430 | static tree | |
4682ae04 | 431 | find_base_decl (tree t) |
3bdf5ad1 | 432 | { |
6615c446 | 433 | tree d0, d1; |
3bdf5ad1 RK |
434 | |
435 | if (t == 0 || t == error_mark_node || ! POINTER_TYPE_P (TREE_TYPE (t))) | |
436 | return 0; | |
437 | ||
4e3825db MM |
438 | if (TREE_CODE (t) == SSA_NAME) |
439 | t = SSA_NAME_VAR (t); | |
440 | ||
0b494699 ILT |
441 | /* If this is a declaration, return it. If T is based on a restrict |
442 | qualified decl, return that decl. */ | |
6615c446 | 443 | if (DECL_P (t)) |
0b494699 ILT |
444 | { |
445 | if (TREE_CODE (t) == VAR_DECL && DECL_BASED_ON_RESTRICT_P (t)) | |
446 | t = DECL_GET_RESTRICT_BASE (t); | |
447 | return t; | |
448 | } | |
3bdf5ad1 RK |
449 | |
450 | /* Handle general expressions. It would be nice to deal with | |
451 | COMPONENT_REFs here. If we could tell that `a' and `b' were the | |
452 | same, then `a->f' and `b->f' are also the same. */ | |
453 | switch (TREE_CODE_CLASS (TREE_CODE (t))) | |
454 | { | |
6615c446 | 455 | case tcc_unary: |
3bdf5ad1 RK |
456 | return find_base_decl (TREE_OPERAND (t, 0)); |
457 | ||
6615c446 | 458 | case tcc_binary: |
3bdf5ad1 RK |
459 | /* Return 0 if found in neither or both are the same. */ |
460 | d0 = find_base_decl (TREE_OPERAND (t, 0)); | |
461 | d1 = find_base_decl (TREE_OPERAND (t, 1)); | |
462 | if (d0 == d1) | |
463 | return d0; | |
464 | else if (d0 == 0) | |
465 | return d1; | |
466 | else if (d1 == 0) | |
467 | return d0; | |
468 | else | |
469 | return 0; | |
470 | ||
3bdf5ad1 RK |
471 | default: |
472 | return 0; | |
473 | } | |
474 | } | |
475 | ||
2039d7aa RH |
476 | /* Return true if all nested component references handled by |
477 | get_inner_reference in T are such that we should use the alias set | |
478 | provided by the object at the heart of T. | |
479 | ||
480 | This is true for non-addressable components (which don't have their | |
481 | own alias set), as well as components of objects in alias set zero. | |
482 | This later point is a special case wherein we wish to override the | |
483 | alias set used by the component, but we don't have per-FIELD_DECL | |
484 | assignable alias sets. */ | |
485 | ||
486 | bool | |
22ea9ec0 | 487 | component_uses_parent_alias_set (const_tree t) |
6e24b709 | 488 | { |
afe84921 RH |
489 | while (1) |
490 | { | |
2039d7aa | 491 | /* If we're at the end, it vacuously uses its own alias set. */ |
afe84921 | 492 | if (!handled_component_p (t)) |
2039d7aa | 493 | return false; |
afe84921 RH |
494 | |
495 | switch (TREE_CODE (t)) | |
496 | { | |
497 | case COMPONENT_REF: | |
498 | if (DECL_NONADDRESSABLE_P (TREE_OPERAND (t, 1))) | |
2039d7aa | 499 | return true; |
afe84921 RH |
500 | break; |
501 | ||
502 | case ARRAY_REF: | |
503 | case ARRAY_RANGE_REF: | |
504 | if (TYPE_NONALIASED_COMPONENT (TREE_TYPE (TREE_OPERAND (t, 0)))) | |
2039d7aa | 505 | return true; |
afe84921 RH |
506 | break; |
507 | ||
508 | case REALPART_EXPR: | |
509 | case IMAGPART_EXPR: | |
510 | break; | |
511 | ||
512 | default: | |
513 | /* Bitfields and casts are never addressable. */ | |
2039d7aa | 514 | return true; |
afe84921 RH |
515 | } |
516 | ||
517 | t = TREE_OPERAND (t, 0); | |
2039d7aa RH |
518 | if (get_alias_set (TREE_TYPE (t)) == 0) |
519 | return true; | |
afe84921 | 520 | } |
6e24b709 RK |
521 | } |
522 | ||
5006671f RG |
523 | /* Return the alias set for the memory pointed to by T, which may be |
524 | either a type or an expression. Return -1 if there is nothing | |
525 | special about dereferencing T. */ | |
526 | ||
527 | static alias_set_type | |
528 | get_deref_alias_set_1 (tree t) | |
529 | { | |
530 | /* If we're not doing any alias analysis, just assume everything | |
531 | aliases everything else. */ | |
532 | if (!flag_strict_aliasing) | |
533 | return 0; | |
534 | ||
535 | if (! TYPE_P (t)) | |
536 | { | |
537 | tree decl = find_base_decl (t); | |
538 | ||
539 | if (decl && DECL_POINTER_ALIAS_SET_KNOWN_P (decl)) | |
540 | { | |
541 | /* If we haven't computed the actual alias set, do it now. */ | |
542 | if (DECL_POINTER_ALIAS_SET (decl) == -2) | |
543 | { | |
544 | tree pointed_to_type = TREE_TYPE (TREE_TYPE (decl)); | |
545 | ||
546 | /* No two restricted pointers can point at the same thing. | |
547 | However, a restricted pointer can point at the same thing | |
548 | as an unrestricted pointer, if that unrestricted pointer | |
549 | is based on the restricted pointer. So, we make the | |
550 | alias set for the restricted pointer a subset of the | |
551 | alias set for the type pointed to by the type of the | |
552 | decl. */ | |
553 | alias_set_type pointed_to_alias_set | |
554 | = get_alias_set (pointed_to_type); | |
555 | ||
556 | if (pointed_to_alias_set == 0) | |
557 | /* It's not legal to make a subset of alias set zero. */ | |
558 | DECL_POINTER_ALIAS_SET (decl) = 0; | |
559 | else if (AGGREGATE_TYPE_P (pointed_to_type)) | |
560 | /* For an aggregate, we must treat the restricted | |
561 | pointer the same as an ordinary pointer. If we | |
562 | were to make the type pointed to by the | |
563 | restricted pointer a subset of the pointed-to | |
564 | type, then we would believe that other subsets | |
565 | of the pointed-to type (such as fields of that | |
566 | type) do not conflict with the type pointed to | |
567 | by the restricted pointer. */ | |
568 | DECL_POINTER_ALIAS_SET (decl) | |
569 | = pointed_to_alias_set; | |
570 | else | |
571 | { | |
572 | DECL_POINTER_ALIAS_SET (decl) = new_alias_set (); | |
573 | record_alias_subset (pointed_to_alias_set, | |
574 | DECL_POINTER_ALIAS_SET (decl)); | |
575 | } | |
576 | } | |
577 | ||
578 | /* We use the alias set indicated in the declaration. */ | |
579 | return DECL_POINTER_ALIAS_SET (decl); | |
580 | } | |
581 | ||
582 | /* Now all we care about is the type. */ | |
583 | t = TREE_TYPE (t); | |
584 | } | |
585 | ||
586 | /* If we have an INDIRECT_REF via a void pointer, we don't | |
587 | know anything about what that might alias. Likewise if the | |
588 | pointer is marked that way. */ | |
589 | if (TREE_CODE (TREE_TYPE (t)) == VOID_TYPE | |
590 | || TYPE_REF_CAN_ALIAS_ALL (t)) | |
591 | return 0; | |
592 | ||
593 | return -1; | |
594 | } | |
595 | ||
596 | /* Return the alias set for the memory pointed to by T, which may be | |
597 | either a type or an expression. */ | |
598 | ||
599 | alias_set_type | |
600 | get_deref_alias_set (tree t) | |
601 | { | |
602 | alias_set_type set = get_deref_alias_set_1 (t); | |
603 | ||
604 | /* Fall back to the alias-set of the pointed-to type. */ | |
605 | if (set == -1) | |
606 | { | |
607 | if (! TYPE_P (t)) | |
608 | t = TREE_TYPE (t); | |
609 | set = get_alias_set (TREE_TYPE (t)); | |
610 | } | |
611 | ||
612 | return set; | |
613 | } | |
614 | ||
3bdf5ad1 RK |
615 | /* Return the alias set for T, which may be either a type or an |
616 | expression. Call language-specific routine for help, if needed. */ | |
617 | ||
4862826d | 618 | alias_set_type |
4682ae04 | 619 | get_alias_set (tree t) |
3bdf5ad1 | 620 | { |
4862826d | 621 | alias_set_type set; |
3bdf5ad1 RK |
622 | |
623 | /* If we're not doing any alias analysis, just assume everything | |
624 | aliases everything else. Also return 0 if this or its type is | |
625 | an error. */ | |
626 | if (! flag_strict_aliasing || t == error_mark_node | |
627 | || (! TYPE_P (t) | |
628 | && (TREE_TYPE (t) == 0 || TREE_TYPE (t) == error_mark_node))) | |
629 | return 0; | |
630 | ||
631 | /* We can be passed either an expression or a type. This and the | |
f47e9b4e RK |
632 | language-specific routine may make mutually-recursive calls to each other |
633 | to figure out what to do. At each juncture, we see if this is a tree | |
634 | that the language may need to handle specially. First handle things that | |
738cc472 | 635 | aren't types. */ |
f824e5c3 | 636 | if (! TYPE_P (t)) |
3bdf5ad1 | 637 | { |
738cc472 | 638 | tree inner = t; |
738cc472 | 639 | |
8ac61af7 RK |
640 | /* Remove any nops, then give the language a chance to do |
641 | something with this tree before we look at it. */ | |
642 | STRIP_NOPS (t); | |
ae2bcd98 | 643 | set = lang_hooks.get_alias_set (t); |
8ac61af7 RK |
644 | if (set != -1) |
645 | return set; | |
646 | ||
738cc472 | 647 | /* First see if the actual object referenced is an INDIRECT_REF from a |
6fce44af RK |
648 | restrict-qualified pointer or a "void *". */ |
649 | while (handled_component_p (inner)) | |
738cc472 | 650 | { |
6fce44af | 651 | inner = TREE_OPERAND (inner, 0); |
8ac61af7 | 652 | STRIP_NOPS (inner); |
738cc472 RK |
653 | } |
654 | ||
1b096a0a | 655 | if (INDIRECT_REF_P (inner)) |
738cc472 | 656 | { |
5006671f RG |
657 | set = get_deref_alias_set_1 (TREE_OPERAND (inner, 0)); |
658 | if (set != -1) | |
659 | return set; | |
738cc472 RK |
660 | } |
661 | ||
662 | /* Otherwise, pick up the outermost object that we could have a pointer | |
6fce44af | 663 | to, processing conversions as above. */ |
2039d7aa | 664 | while (component_uses_parent_alias_set (t)) |
f47e9b4e | 665 | { |
6fce44af | 666 | t = TREE_OPERAND (t, 0); |
8ac61af7 RK |
667 | STRIP_NOPS (t); |
668 | } | |
f824e5c3 | 669 | |
738cc472 RK |
670 | /* If we've already determined the alias set for a decl, just return |
671 | it. This is necessary for C++ anonymous unions, whose component | |
672 | variables don't look like union members (boo!). */ | |
5755cd38 | 673 | if (TREE_CODE (t) == VAR_DECL |
3c0cb5de | 674 | && DECL_RTL_SET_P (t) && MEM_P (DECL_RTL (t))) |
5755cd38 JM |
675 | return MEM_ALIAS_SET (DECL_RTL (t)); |
676 | ||
f824e5c3 RK |
677 | /* Now all we care about is the type. */ |
678 | t = TREE_TYPE (t); | |
3bdf5ad1 RK |
679 | } |
680 | ||
3bdf5ad1 | 681 | /* Variant qualifiers don't affect the alias set, so get the main |
791f1714 RG |
682 | variant. Always use the canonical type as well. |
683 | If this is a type with a known alias set, return it. */ | |
3bdf5ad1 | 684 | t = TYPE_MAIN_VARIANT (t); |
791f1714 RG |
685 | if (TYPE_CANONICAL (t)) |
686 | t = TYPE_CANONICAL (t); | |
738cc472 | 687 | if (TYPE_ALIAS_SET_KNOWN_P (t)) |
3bdf5ad1 RK |
688 | return TYPE_ALIAS_SET (t); |
689 | ||
36784d0e RG |
690 | /* We don't want to set TYPE_ALIAS_SET for incomplete types. */ |
691 | if (!COMPLETE_TYPE_P (t)) | |
692 | { | |
693 | /* For arrays with unknown size the conservative answer is the | |
694 | alias set of the element type. */ | |
695 | if (TREE_CODE (t) == ARRAY_TYPE) | |
696 | return get_alias_set (TREE_TYPE (t)); | |
697 | ||
698 | /* But return zero as a conservative answer for incomplete types. */ | |
699 | return 0; | |
700 | } | |
701 | ||
3bdf5ad1 | 702 | /* See if the language has special handling for this type. */ |
ae2bcd98 | 703 | set = lang_hooks.get_alias_set (t); |
8ac61af7 | 704 | if (set != -1) |
738cc472 | 705 | return set; |
2bf105ab | 706 | |
3bdf5ad1 RK |
707 | /* There are no objects of FUNCTION_TYPE, so there's no point in |
708 | using up an alias set for them. (There are, of course, pointers | |
709 | and references to functions, but that's different.) */ | |
e11e491d RG |
710 | else if (TREE_CODE (t) == FUNCTION_TYPE |
711 | || TREE_CODE (t) == METHOD_TYPE) | |
3bdf5ad1 | 712 | set = 0; |
74d86f4f RH |
713 | |
714 | /* Unless the language specifies otherwise, let vector types alias | |
715 | their components. This avoids some nasty type punning issues in | |
716 | normal usage. And indeed lets vectors be treated more like an | |
717 | array slice. */ | |
718 | else if (TREE_CODE (t) == VECTOR_TYPE) | |
719 | set = get_alias_set (TREE_TYPE (t)); | |
720 | ||
4653cae5 RG |
721 | /* Unless the language specifies otherwise, treat array types the |
722 | same as their components. This avoids the asymmetry we get | |
723 | through recording the components. Consider accessing a | |
724 | character(kind=1) through a reference to a character(kind=1)[1:1]. | |
725 | Or consider if we want to assign integer(kind=4)[0:D.1387] and | |
726 | integer(kind=4)[4] the same alias set or not. | |
727 | Just be pragmatic here and make sure the array and its element | |
728 | type get the same alias set assigned. */ | |
729 | else if (TREE_CODE (t) == ARRAY_TYPE | |
730 | && !TYPE_NONALIASED_COMPONENT (t)) | |
731 | set = get_alias_set (TREE_TYPE (t)); | |
732 | ||
3bdf5ad1 RK |
733 | else |
734 | /* Otherwise make a new alias set for this type. */ | |
735 | set = new_alias_set (); | |
736 | ||
737 | TYPE_ALIAS_SET (t) = set; | |
2bf105ab RK |
738 | |
739 | /* If this is an aggregate type, we must record any component aliasing | |
740 | information. */ | |
1d79fd2c | 741 | if (AGGREGATE_TYPE_P (t) || TREE_CODE (t) == COMPLEX_TYPE) |
2bf105ab RK |
742 | record_component_aliases (t); |
743 | ||
3bdf5ad1 RK |
744 | return set; |
745 | } | |
746 | ||
747 | /* Return a brand-new alias set. */ | |
748 | ||
4862826d | 749 | alias_set_type |
4682ae04 | 750 | new_alias_set (void) |
3bdf5ad1 | 751 | { |
3bdf5ad1 | 752 | if (flag_strict_aliasing) |
9ddb66ca | 753 | { |
1a5640b4 KH |
754 | if (alias_sets == 0) |
755 | VEC_safe_push (alias_set_entry, gc, alias_sets, 0); | |
756 | VEC_safe_push (alias_set_entry, gc, alias_sets, 0); | |
757 | return VEC_length (alias_set_entry, alias_sets) - 1; | |
9ddb66ca | 758 | } |
3bdf5ad1 RK |
759 | else |
760 | return 0; | |
761 | } | |
3932261a | 762 | |
01d28c3f JM |
763 | /* Indicate that things in SUBSET can alias things in SUPERSET, but that |
764 | not everything that aliases SUPERSET also aliases SUBSET. For example, | |
765 | in C, a store to an `int' can alias a load of a structure containing an | |
766 | `int', and vice versa. But it can't alias a load of a 'double' member | |
767 | of the same structure. Here, the structure would be the SUPERSET and | |
768 | `int' the SUBSET. This relationship is also described in the comment at | |
769 | the beginning of this file. | |
770 | ||
771 | This function should be called only once per SUPERSET/SUBSET pair. | |
3932261a MM |
772 | |
773 | It is illegal for SUPERSET to be zero; everything is implicitly a | |
774 | subset of alias set zero. */ | |
775 | ||
794511d2 | 776 | void |
4862826d | 777 | record_alias_subset (alias_set_type superset, alias_set_type subset) |
3932261a MM |
778 | { |
779 | alias_set_entry superset_entry; | |
780 | alias_set_entry subset_entry; | |
781 | ||
f47e9b4e RK |
782 | /* It is possible in complex type situations for both sets to be the same, |
783 | in which case we can ignore this operation. */ | |
784 | if (superset == subset) | |
785 | return; | |
786 | ||
298e6adc | 787 | gcc_assert (superset); |
3932261a MM |
788 | |
789 | superset_entry = get_alias_set_entry (superset); | |
ca7fd9cd | 790 | if (superset_entry == 0) |
3932261a MM |
791 | { |
792 | /* Create an entry for the SUPERSET, so that we have a place to | |
793 | attach the SUBSET. */ | |
7e5487a2 | 794 | superset_entry = GGC_NEW (struct alias_set_entry_d); |
3932261a | 795 | superset_entry->alias_set = superset; |
ca7fd9cd | 796 | superset_entry->children |
b604074c | 797 | = splay_tree_new_ggc (splay_tree_compare_ints); |
570eb5c8 | 798 | superset_entry->has_zero_child = 0; |
1a5640b4 | 799 | VEC_replace (alias_set_entry, alias_sets, superset, superset_entry); |
3932261a MM |
800 | } |
801 | ||
2bf105ab RK |
802 | if (subset == 0) |
803 | superset_entry->has_zero_child = 1; | |
804 | else | |
805 | { | |
806 | subset_entry = get_alias_set_entry (subset); | |
807 | /* If there is an entry for the subset, enter all of its children | |
808 | (if they are not already present) as children of the SUPERSET. */ | |
ca7fd9cd | 809 | if (subset_entry) |
2bf105ab RK |
810 | { |
811 | if (subset_entry->has_zero_child) | |
812 | superset_entry->has_zero_child = 1; | |
d4b60170 | 813 | |
2bf105ab RK |
814 | splay_tree_foreach (subset_entry->children, insert_subset_children, |
815 | superset_entry->children); | |
816 | } | |
3932261a | 817 | |
2bf105ab | 818 | /* Enter the SUBSET itself as a child of the SUPERSET. */ |
ca7fd9cd | 819 | splay_tree_insert (superset_entry->children, |
2bf105ab RK |
820 | (splay_tree_key) subset, 0); |
821 | } | |
3932261a MM |
822 | } |
823 | ||
a0c33338 RK |
824 | /* Record that component types of TYPE, if any, are part of that type for |
825 | aliasing purposes. For record types, we only record component types | |
b5487346 EB |
826 | for fields that are not marked non-addressable. For array types, we |
827 | only record the component type if it is not marked non-aliased. */ | |
a0c33338 RK |
828 | |
829 | void | |
4682ae04 | 830 | record_component_aliases (tree type) |
a0c33338 | 831 | { |
4862826d | 832 | alias_set_type superset = get_alias_set (type); |
a0c33338 RK |
833 | tree field; |
834 | ||
835 | if (superset == 0) | |
836 | return; | |
837 | ||
838 | switch (TREE_CODE (type)) | |
839 | { | |
a0c33338 RK |
840 | case RECORD_TYPE: |
841 | case UNION_TYPE: | |
842 | case QUAL_UNION_TYPE: | |
6614fd40 | 843 | /* Recursively record aliases for the base classes, if there are any. */ |
fa743e8c | 844 | if (TYPE_BINFO (type)) |
ca7fd9cd KH |
845 | { |
846 | int i; | |
fa743e8c | 847 | tree binfo, base_binfo; |
c22cacf3 | 848 | |
fa743e8c NS |
849 | for (binfo = TYPE_BINFO (type), i = 0; |
850 | BINFO_BASE_ITERATE (binfo, i, base_binfo); i++) | |
851 | record_alias_subset (superset, | |
852 | get_alias_set (BINFO_TYPE (base_binfo))); | |
ca7fd9cd | 853 | } |
a0c33338 | 854 | for (field = TYPE_FIELDS (type); field != 0; field = TREE_CHAIN (field)) |
b5487346 | 855 | if (TREE_CODE (field) == FIELD_DECL && !DECL_NONADDRESSABLE_P (field)) |
2bf105ab | 856 | record_alias_subset (superset, get_alias_set (TREE_TYPE (field))); |
a0c33338 RK |
857 | break; |
858 | ||
1d79fd2c JW |
859 | case COMPLEX_TYPE: |
860 | record_alias_subset (superset, get_alias_set (TREE_TYPE (type))); | |
861 | break; | |
862 | ||
4653cae5 RG |
863 | /* VECTOR_TYPE and ARRAY_TYPE share the alias set with their |
864 | element type. */ | |
865 | ||
a0c33338 RK |
866 | default: |
867 | break; | |
868 | } | |
869 | } | |
870 | ||
3bdf5ad1 RK |
871 | /* Allocate an alias set for use in storing and reading from the varargs |
872 | spill area. */ | |
873 | ||
4862826d | 874 | static GTY(()) alias_set_type varargs_set = -1; |
f103e34d | 875 | |
4862826d | 876 | alias_set_type |
4682ae04 | 877 | get_varargs_alias_set (void) |
3bdf5ad1 | 878 | { |
cd3ce9b4 JM |
879 | #if 1 |
880 | /* We now lower VA_ARG_EXPR, and there's currently no way to attach the | |
881 | varargs alias set to an INDIRECT_REF (FIXME!), so we can't | |
882 | consistently use the varargs alias set for loads from the varargs | |
883 | area. So don't use it anywhere. */ | |
884 | return 0; | |
885 | #else | |
f103e34d GK |
886 | if (varargs_set == -1) |
887 | varargs_set = new_alias_set (); | |
3bdf5ad1 | 888 | |
f103e34d | 889 | return varargs_set; |
cd3ce9b4 | 890 | #endif |
3bdf5ad1 RK |
891 | } |
892 | ||
893 | /* Likewise, but used for the fixed portions of the frame, e.g., register | |
894 | save areas. */ | |
895 | ||
4862826d | 896 | static GTY(()) alias_set_type frame_set = -1; |
f103e34d | 897 | |
4862826d | 898 | alias_set_type |
4682ae04 | 899 | get_frame_alias_set (void) |
3bdf5ad1 | 900 | { |
f103e34d GK |
901 | if (frame_set == -1) |
902 | frame_set = new_alias_set (); | |
3bdf5ad1 | 903 | |
f103e34d | 904 | return frame_set; |
3bdf5ad1 RK |
905 | } |
906 | ||
2a2c8203 JC |
907 | /* Inside SRC, the source of a SET, find a base address. */ |
908 | ||
9ae8ffe7 | 909 | static rtx |
4682ae04 | 910 | find_base_value (rtx src) |
9ae8ffe7 | 911 | { |
713f41f9 | 912 | unsigned int regno; |
0aacc8ed | 913 | |
53451050 RS |
914 | #if defined (FIND_BASE_TERM) |
915 | /* Try machine-dependent ways to find the base term. */ | |
916 | src = FIND_BASE_TERM (src); | |
917 | #endif | |
918 | ||
9ae8ffe7 JL |
919 | switch (GET_CODE (src)) |
920 | { | |
921 | case SYMBOL_REF: | |
922 | case LABEL_REF: | |
923 | return src; | |
924 | ||
925 | case REG: | |
fb6754f0 | 926 | regno = REGNO (src); |
d4b60170 | 927 | /* At the start of a function, argument registers have known base |
2a2c8203 JC |
928 | values which may be lost later. Returning an ADDRESS |
929 | expression here allows optimization based on argument values | |
930 | even when the argument registers are used for other purposes. */ | |
713f41f9 BS |
931 | if (regno < FIRST_PSEUDO_REGISTER && copying_arguments) |
932 | return new_reg_base_value[regno]; | |
73774bc7 | 933 | |
eaf407a5 | 934 | /* If a pseudo has a known base value, return it. Do not do this |
9b462c42 RH |
935 | for non-fixed hard regs since it can result in a circular |
936 | dependency chain for registers which have values at function entry. | |
eaf407a5 JL |
937 | |
938 | The test above is not sufficient because the scheduler may move | |
939 | a copy out of an arg reg past the NOTE_INSN_FUNCTION_BEGIN. */ | |
9b462c42 | 940 | if ((regno >= FIRST_PSEUDO_REGISTER || fixed_regs[regno]) |
08c79682 | 941 | && regno < VEC_length (rtx, reg_base_value)) |
83bbd9b6 RH |
942 | { |
943 | /* If we're inside init_alias_analysis, use new_reg_base_value | |
944 | to reduce the number of relaxation iterations. */ | |
1afdf91c | 945 | if (new_reg_base_value && new_reg_base_value[regno] |
6fb5fa3c | 946 | && DF_REG_DEF_COUNT (regno) == 1) |
83bbd9b6 RH |
947 | return new_reg_base_value[regno]; |
948 | ||
08c79682 KH |
949 | if (VEC_index (rtx, reg_base_value, regno)) |
950 | return VEC_index (rtx, reg_base_value, regno); | |
83bbd9b6 | 951 | } |
73774bc7 | 952 | |
e3f049a8 | 953 | return 0; |
9ae8ffe7 JL |
954 | |
955 | case MEM: | |
956 | /* Check for an argument passed in memory. Only record in the | |
957 | copying-arguments block; it is too hard to track changes | |
958 | otherwise. */ | |
959 | if (copying_arguments | |
960 | && (XEXP (src, 0) == arg_pointer_rtx | |
961 | || (GET_CODE (XEXP (src, 0)) == PLUS | |
962 | && XEXP (XEXP (src, 0), 0) == arg_pointer_rtx))) | |
38a448ca | 963 | return gen_rtx_ADDRESS (VOIDmode, src); |
9ae8ffe7 JL |
964 | return 0; |
965 | ||
966 | case CONST: | |
967 | src = XEXP (src, 0); | |
968 | if (GET_CODE (src) != PLUS && GET_CODE (src) != MINUS) | |
969 | break; | |
d4b60170 | 970 | |
ec5c56db | 971 | /* ... fall through ... */ |
2a2c8203 | 972 | |
9ae8ffe7 JL |
973 | case PLUS: |
974 | case MINUS: | |
2a2c8203 | 975 | { |
ec907dd8 JL |
976 | rtx temp, src_0 = XEXP (src, 0), src_1 = XEXP (src, 1); |
977 | ||
0134bf2d DE |
978 | /* If either operand is a REG that is a known pointer, then it |
979 | is the base. */ | |
980 | if (REG_P (src_0) && REG_POINTER (src_0)) | |
981 | return find_base_value (src_0); | |
982 | if (REG_P (src_1) && REG_POINTER (src_1)) | |
983 | return find_base_value (src_1); | |
984 | ||
ec907dd8 JL |
985 | /* If either operand is a REG, then see if we already have |
986 | a known value for it. */ | |
0134bf2d | 987 | if (REG_P (src_0)) |
ec907dd8 JL |
988 | { |
989 | temp = find_base_value (src_0); | |
d4b60170 | 990 | if (temp != 0) |
ec907dd8 JL |
991 | src_0 = temp; |
992 | } | |
993 | ||
0134bf2d | 994 | if (REG_P (src_1)) |
ec907dd8 JL |
995 | { |
996 | temp = find_base_value (src_1); | |
d4b60170 | 997 | if (temp!= 0) |
ec907dd8 JL |
998 | src_1 = temp; |
999 | } | |
2a2c8203 | 1000 | |
0134bf2d DE |
1001 | /* If either base is named object or a special address |
1002 | (like an argument or stack reference), then use it for the | |
1003 | base term. */ | |
1004 | if (src_0 != 0 | |
1005 | && (GET_CODE (src_0) == SYMBOL_REF | |
1006 | || GET_CODE (src_0) == LABEL_REF | |
1007 | || (GET_CODE (src_0) == ADDRESS | |
1008 | && GET_MODE (src_0) != VOIDmode))) | |
1009 | return src_0; | |
1010 | ||
1011 | if (src_1 != 0 | |
1012 | && (GET_CODE (src_1) == SYMBOL_REF | |
1013 | || GET_CODE (src_1) == LABEL_REF | |
1014 | || (GET_CODE (src_1) == ADDRESS | |
1015 | && GET_MODE (src_1) != VOIDmode))) | |
1016 | return src_1; | |
1017 | ||
d4b60170 | 1018 | /* Guess which operand is the base address: |
ec907dd8 JL |
1019 | If either operand is a symbol, then it is the base. If |
1020 | either operand is a CONST_INT, then the other is the base. */ | |
481683e1 | 1021 | if (CONST_INT_P (src_1) || CONSTANT_P (src_0)) |
2a2c8203 | 1022 | return find_base_value (src_0); |
481683e1 | 1023 | else if (CONST_INT_P (src_0) || CONSTANT_P (src_1)) |
ec907dd8 JL |
1024 | return find_base_value (src_1); |
1025 | ||
9ae8ffe7 | 1026 | return 0; |
2a2c8203 JC |
1027 | } |
1028 | ||
1029 | case LO_SUM: | |
1030 | /* The standard form is (lo_sum reg sym) so look only at the | |
1031 | second operand. */ | |
1032 | return find_base_value (XEXP (src, 1)); | |
9ae8ffe7 JL |
1033 | |
1034 | case AND: | |
1035 | /* If the second operand is constant set the base | |
ec5c56db | 1036 | address to the first operand. */ |
481683e1 | 1037 | if (CONST_INT_P (XEXP (src, 1)) && INTVAL (XEXP (src, 1)) != 0) |
2a2c8203 | 1038 | return find_base_value (XEXP (src, 0)); |
9ae8ffe7 JL |
1039 | return 0; |
1040 | ||
61f0131c R |
1041 | case TRUNCATE: |
1042 | if (GET_MODE_SIZE (GET_MODE (src)) < GET_MODE_SIZE (Pmode)) | |
1043 | break; | |
1044 | /* Fall through. */ | |
9ae8ffe7 | 1045 | case HIGH: |
d288e53d DE |
1046 | case PRE_INC: |
1047 | case PRE_DEC: | |
1048 | case POST_INC: | |
1049 | case POST_DEC: | |
1050 | case PRE_MODIFY: | |
1051 | case POST_MODIFY: | |
2a2c8203 | 1052 | return find_base_value (XEXP (src, 0)); |
1d300e19 | 1053 | |
0aacc8ed RK |
1054 | case ZERO_EXTEND: |
1055 | case SIGN_EXTEND: /* used for NT/Alpha pointers */ | |
1056 | { | |
1057 | rtx temp = find_base_value (XEXP (src, 0)); | |
1058 | ||
5ae6cd0d | 1059 | if (temp != 0 && CONSTANT_P (temp)) |
0aacc8ed | 1060 | temp = convert_memory_address (Pmode, temp); |
0aacc8ed RK |
1061 | |
1062 | return temp; | |
1063 | } | |
1064 | ||
1d300e19 KG |
1065 | default: |
1066 | break; | |
9ae8ffe7 JL |
1067 | } |
1068 | ||
1069 | return 0; | |
1070 | } | |
1071 | ||
1072 | /* Called from init_alias_analysis indirectly through note_stores. */ | |
1073 | ||
d4b60170 | 1074 | /* While scanning insns to find base values, reg_seen[N] is nonzero if |
9ae8ffe7 JL |
1075 | register N has been set in this function. */ |
1076 | static char *reg_seen; | |
1077 | ||
13309a5f JC |
1078 | /* Addresses which are known not to alias anything else are identified |
1079 | by a unique integer. */ | |
ec907dd8 JL |
1080 | static int unique_id; |
1081 | ||
2a2c8203 | 1082 | static void |
7bc980e1 | 1083 | record_set (rtx dest, const_rtx set, void *data ATTRIBUTE_UNUSED) |
9ae8ffe7 | 1084 | { |
b3694847 | 1085 | unsigned regno; |
9ae8ffe7 | 1086 | rtx src; |
c28b4e40 | 1087 | int n; |
9ae8ffe7 | 1088 | |
f8cfc6aa | 1089 | if (!REG_P (dest)) |
9ae8ffe7 JL |
1090 | return; |
1091 | ||
fb6754f0 | 1092 | regno = REGNO (dest); |
9ae8ffe7 | 1093 | |
08c79682 | 1094 | gcc_assert (regno < VEC_length (rtx, reg_base_value)); |
ac606739 | 1095 | |
c28b4e40 JW |
1096 | /* If this spans multiple hard registers, then we must indicate that every |
1097 | register has an unusable value. */ | |
1098 | if (regno < FIRST_PSEUDO_REGISTER) | |
66fd46b6 | 1099 | n = hard_regno_nregs[regno][GET_MODE (dest)]; |
c28b4e40 JW |
1100 | else |
1101 | n = 1; | |
1102 | if (n != 1) | |
1103 | { | |
1104 | while (--n >= 0) | |
1105 | { | |
1106 | reg_seen[regno + n] = 1; | |
1107 | new_reg_base_value[regno + n] = 0; | |
1108 | } | |
1109 | return; | |
1110 | } | |
1111 | ||
9ae8ffe7 JL |
1112 | if (set) |
1113 | { | |
1114 | /* A CLOBBER wipes out any old value but does not prevent a previously | |
1115 | unset register from acquiring a base address (i.e. reg_seen is not | |
1116 | set). */ | |
1117 | if (GET_CODE (set) == CLOBBER) | |
1118 | { | |
ec907dd8 | 1119 | new_reg_base_value[regno] = 0; |
9ae8ffe7 JL |
1120 | return; |
1121 | } | |
1122 | src = SET_SRC (set); | |
1123 | } | |
1124 | else | |
1125 | { | |
9ae8ffe7 JL |
1126 | if (reg_seen[regno]) |
1127 | { | |
ec907dd8 | 1128 | new_reg_base_value[regno] = 0; |
9ae8ffe7 JL |
1129 | return; |
1130 | } | |
1131 | reg_seen[regno] = 1; | |
38a448ca RH |
1132 | new_reg_base_value[regno] = gen_rtx_ADDRESS (Pmode, |
1133 | GEN_INT (unique_id++)); | |
9ae8ffe7 JL |
1134 | return; |
1135 | } | |
1136 | ||
5da6f168 RS |
1137 | /* If this is not the first set of REGNO, see whether the new value |
1138 | is related to the old one. There are two cases of interest: | |
1139 | ||
1140 | (1) The register might be assigned an entirely new value | |
1141 | that has the same base term as the original set. | |
1142 | ||
1143 | (2) The set might be a simple self-modification that | |
1144 | cannot change REGNO's base value. | |
1145 | ||
1146 | If neither case holds, reject the original base value as invalid. | |
1147 | Note that the following situation is not detected: | |
1148 | ||
c22cacf3 | 1149 | extern int x, y; int *p = &x; p += (&y-&x); |
5da6f168 | 1150 | |
9ae8ffe7 JL |
1151 | ANSI C does not allow computing the difference of addresses |
1152 | of distinct top level objects. */ | |
5da6f168 RS |
1153 | if (new_reg_base_value[regno] != 0 |
1154 | && find_base_value (src) != new_reg_base_value[regno]) | |
9ae8ffe7 JL |
1155 | switch (GET_CODE (src)) |
1156 | { | |
2a2c8203 | 1157 | case LO_SUM: |
9ae8ffe7 JL |
1158 | case MINUS: |
1159 | if (XEXP (src, 0) != dest && XEXP (src, 1) != dest) | |
ec907dd8 | 1160 | new_reg_base_value[regno] = 0; |
9ae8ffe7 | 1161 | break; |
61f0131c R |
1162 | case PLUS: |
1163 | /* If the value we add in the PLUS is also a valid base value, | |
1164 | this might be the actual base value, and the original value | |
1165 | an index. */ | |
1166 | { | |
1167 | rtx other = NULL_RTX; | |
1168 | ||
1169 | if (XEXP (src, 0) == dest) | |
1170 | other = XEXP (src, 1); | |
1171 | else if (XEXP (src, 1) == dest) | |
1172 | other = XEXP (src, 0); | |
1173 | ||
1174 | if (! other || find_base_value (other)) | |
1175 | new_reg_base_value[regno] = 0; | |
1176 | break; | |
1177 | } | |
9ae8ffe7 | 1178 | case AND: |
481683e1 | 1179 | if (XEXP (src, 0) != dest || !CONST_INT_P (XEXP (src, 1))) |
ec907dd8 | 1180 | new_reg_base_value[regno] = 0; |
9ae8ffe7 | 1181 | break; |
9ae8ffe7 | 1182 | default: |
ec907dd8 | 1183 | new_reg_base_value[regno] = 0; |
9ae8ffe7 JL |
1184 | break; |
1185 | } | |
1186 | /* If this is the first set of a register, record the value. */ | |
1187 | else if ((regno >= FIRST_PSEUDO_REGISTER || ! fixed_regs[regno]) | |
ec907dd8 JL |
1188 | && ! reg_seen[regno] && new_reg_base_value[regno] == 0) |
1189 | new_reg_base_value[regno] = find_base_value (src); | |
9ae8ffe7 JL |
1190 | |
1191 | reg_seen[regno] = 1; | |
1192 | } | |
1193 | ||
bb1acb3e RH |
1194 | /* If a value is known for REGNO, return it. */ |
1195 | ||
c22cacf3 | 1196 | rtx |
bb1acb3e RH |
1197 | get_reg_known_value (unsigned int regno) |
1198 | { | |
1199 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1200 | { | |
1201 | regno -= FIRST_PSEUDO_REGISTER; | |
1202 | if (regno < reg_known_value_size) | |
1203 | return reg_known_value[regno]; | |
1204 | } | |
1205 | return NULL; | |
43fe47ca JW |
1206 | } |
1207 | ||
bb1acb3e RH |
1208 | /* Set it. */ |
1209 | ||
1210 | static void | |
1211 | set_reg_known_value (unsigned int regno, rtx val) | |
1212 | { | |
1213 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1214 | { | |
1215 | regno -= FIRST_PSEUDO_REGISTER; | |
1216 | if (regno < reg_known_value_size) | |
1217 | reg_known_value[regno] = val; | |
1218 | } | |
1219 | } | |
1220 | ||
1221 | /* Similarly for reg_known_equiv_p. */ | |
1222 | ||
1223 | bool | |
1224 | get_reg_known_equiv_p (unsigned int regno) | |
1225 | { | |
1226 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1227 | { | |
1228 | regno -= FIRST_PSEUDO_REGISTER; | |
1229 | if (regno < reg_known_value_size) | |
1230 | return reg_known_equiv_p[regno]; | |
1231 | } | |
1232 | return false; | |
1233 | } | |
1234 | ||
1235 | static void | |
1236 | set_reg_known_equiv_p (unsigned int regno, bool val) | |
1237 | { | |
1238 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1239 | { | |
1240 | regno -= FIRST_PSEUDO_REGISTER; | |
1241 | if (regno < reg_known_value_size) | |
1242 | reg_known_equiv_p[regno] = val; | |
1243 | } | |
1244 | } | |
1245 | ||
1246 | ||
db048faf MM |
1247 | /* Returns a canonical version of X, from the point of view alias |
1248 | analysis. (For example, if X is a MEM whose address is a register, | |
1249 | and the register has a known value (say a SYMBOL_REF), then a MEM | |
1250 | whose address is the SYMBOL_REF is returned.) */ | |
1251 | ||
1252 | rtx | |
4682ae04 | 1253 | canon_rtx (rtx x) |
9ae8ffe7 JL |
1254 | { |
1255 | /* Recursively look for equivalences. */ | |
f8cfc6aa | 1256 | if (REG_P (x) && REGNO (x) >= FIRST_PSEUDO_REGISTER) |
bb1acb3e RH |
1257 | { |
1258 | rtx t = get_reg_known_value (REGNO (x)); | |
1259 | if (t == x) | |
1260 | return x; | |
1261 | if (t) | |
1262 | return canon_rtx (t); | |
1263 | } | |
1264 | ||
1265 | if (GET_CODE (x) == PLUS) | |
9ae8ffe7 JL |
1266 | { |
1267 | rtx x0 = canon_rtx (XEXP (x, 0)); | |
1268 | rtx x1 = canon_rtx (XEXP (x, 1)); | |
1269 | ||
1270 | if (x0 != XEXP (x, 0) || x1 != XEXP (x, 1)) | |
1271 | { | |
481683e1 | 1272 | if (CONST_INT_P (x0)) |
ed8908e7 | 1273 | return plus_constant (x1, INTVAL (x0)); |
481683e1 | 1274 | else if (CONST_INT_P (x1)) |
ed8908e7 | 1275 | return plus_constant (x0, INTVAL (x1)); |
38a448ca | 1276 | return gen_rtx_PLUS (GET_MODE (x), x0, x1); |
9ae8ffe7 JL |
1277 | } |
1278 | } | |
d4b60170 | 1279 | |
9ae8ffe7 JL |
1280 | /* This gives us much better alias analysis when called from |
1281 | the loop optimizer. Note we want to leave the original | |
1282 | MEM alone, but need to return the canonicalized MEM with | |
1283 | all the flags with their original values. */ | |
3c0cb5de | 1284 | else if (MEM_P (x)) |
f1ec5147 | 1285 | x = replace_equiv_address_nv (x, canon_rtx (XEXP (x, 0))); |
d4b60170 | 1286 | |
9ae8ffe7 JL |
1287 | return x; |
1288 | } | |
1289 | ||
1290 | /* Return 1 if X and Y are identical-looking rtx's. | |
45183e03 | 1291 | Expect that X and Y has been already canonicalized. |
9ae8ffe7 JL |
1292 | |
1293 | We use the data in reg_known_value above to see if two registers with | |
1294 | different numbers are, in fact, equivalent. */ | |
1295 | ||
1296 | static int | |
ed7a4b4b | 1297 | rtx_equal_for_memref_p (const_rtx x, const_rtx y) |
9ae8ffe7 | 1298 | { |
b3694847 SS |
1299 | int i; |
1300 | int j; | |
1301 | enum rtx_code code; | |
1302 | const char *fmt; | |
9ae8ffe7 JL |
1303 | |
1304 | if (x == 0 && y == 0) | |
1305 | return 1; | |
1306 | if (x == 0 || y == 0) | |
1307 | return 0; | |
d4b60170 | 1308 | |
9ae8ffe7 JL |
1309 | if (x == y) |
1310 | return 1; | |
1311 | ||
1312 | code = GET_CODE (x); | |
1313 | /* Rtx's of different codes cannot be equal. */ | |
1314 | if (code != GET_CODE (y)) | |
1315 | return 0; | |
1316 | ||
1317 | /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. | |
1318 | (REG:SI x) and (REG:HI x) are NOT equivalent. */ | |
1319 | ||
1320 | if (GET_MODE (x) != GET_MODE (y)) | |
1321 | return 0; | |
1322 | ||
db048faf MM |
1323 | /* Some RTL can be compared without a recursive examination. */ |
1324 | switch (code) | |
1325 | { | |
1326 | case REG: | |
1327 | return REGNO (x) == REGNO (y); | |
1328 | ||
1329 | case LABEL_REF: | |
1330 | return XEXP (x, 0) == XEXP (y, 0); | |
ca7fd9cd | 1331 | |
db048faf MM |
1332 | case SYMBOL_REF: |
1333 | return XSTR (x, 0) == XSTR (y, 0); | |
1334 | ||
40e02b4a | 1335 | case VALUE: |
db048faf MM |
1336 | case CONST_INT: |
1337 | case CONST_DOUBLE: | |
091a3ac7 | 1338 | case CONST_FIXED: |
db048faf MM |
1339 | /* There's no need to compare the contents of CONST_DOUBLEs or |
1340 | CONST_INTs because pointer equality is a good enough | |
1341 | comparison for these nodes. */ | |
1342 | return 0; | |
1343 | ||
db048faf MM |
1344 | default: |
1345 | break; | |
1346 | } | |
9ae8ffe7 | 1347 | |
45183e03 JH |
1348 | /* canon_rtx knows how to handle plus. No need to canonicalize. */ |
1349 | if (code == PLUS) | |
9ae8ffe7 JL |
1350 | return ((rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 0)) |
1351 | && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 1))) | |
1352 | || (rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 1)) | |
1353 | && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 0)))); | |
45183e03 JH |
1354 | /* For commutative operations, the RTX match if the operand match in any |
1355 | order. Also handle the simple binary and unary cases without a loop. */ | |
ec8e098d | 1356 | if (COMMUTATIVE_P (x)) |
45183e03 JH |
1357 | { |
1358 | rtx xop0 = canon_rtx (XEXP (x, 0)); | |
1359 | rtx yop0 = canon_rtx (XEXP (y, 0)); | |
1360 | rtx yop1 = canon_rtx (XEXP (y, 1)); | |
1361 | ||
1362 | return ((rtx_equal_for_memref_p (xop0, yop0) | |
1363 | && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), yop1)) | |
1364 | || (rtx_equal_for_memref_p (xop0, yop1) | |
1365 | && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), yop0))); | |
1366 | } | |
ec8e098d | 1367 | else if (NON_COMMUTATIVE_P (x)) |
45183e03 JH |
1368 | { |
1369 | return (rtx_equal_for_memref_p (canon_rtx (XEXP (x, 0)), | |
4682ae04 | 1370 | canon_rtx (XEXP (y, 0))) |
45183e03 JH |
1371 | && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), |
1372 | canon_rtx (XEXP (y, 1)))); | |
1373 | } | |
ec8e098d | 1374 | else if (UNARY_P (x)) |
45183e03 | 1375 | return rtx_equal_for_memref_p (canon_rtx (XEXP (x, 0)), |
4682ae04 | 1376 | canon_rtx (XEXP (y, 0))); |
9ae8ffe7 JL |
1377 | |
1378 | /* Compare the elements. If any pair of corresponding elements | |
de12be17 JC |
1379 | fail to match, return 0 for the whole things. |
1380 | ||
1381 | Limit cases to types which actually appear in addresses. */ | |
9ae8ffe7 JL |
1382 | |
1383 | fmt = GET_RTX_FORMAT (code); | |
1384 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
1385 | { | |
1386 | switch (fmt[i]) | |
1387 | { | |
9ae8ffe7 JL |
1388 | case 'i': |
1389 | if (XINT (x, i) != XINT (y, i)) | |
1390 | return 0; | |
1391 | break; | |
1392 | ||
9ae8ffe7 JL |
1393 | case 'E': |
1394 | /* Two vectors must have the same length. */ | |
1395 | if (XVECLEN (x, i) != XVECLEN (y, i)) | |
1396 | return 0; | |
1397 | ||
1398 | /* And the corresponding elements must match. */ | |
1399 | for (j = 0; j < XVECLEN (x, i); j++) | |
45183e03 JH |
1400 | if (rtx_equal_for_memref_p (canon_rtx (XVECEXP (x, i, j)), |
1401 | canon_rtx (XVECEXP (y, i, j))) == 0) | |
9ae8ffe7 JL |
1402 | return 0; |
1403 | break; | |
1404 | ||
1405 | case 'e': | |
45183e03 JH |
1406 | if (rtx_equal_for_memref_p (canon_rtx (XEXP (x, i)), |
1407 | canon_rtx (XEXP (y, i))) == 0) | |
9ae8ffe7 JL |
1408 | return 0; |
1409 | break; | |
1410 | ||
3237ac18 AH |
1411 | /* This can happen for asm operands. */ |
1412 | case 's': | |
1413 | if (strcmp (XSTR (x, i), XSTR (y, i))) | |
1414 | return 0; | |
1415 | break; | |
1416 | ||
aee21ba9 JL |
1417 | /* This can happen for an asm which clobbers memory. */ |
1418 | case '0': | |
1419 | break; | |
1420 | ||
9ae8ffe7 JL |
1421 | /* It is believed that rtx's at this level will never |
1422 | contain anything but integers and other rtx's, | |
1423 | except for within LABEL_REFs and SYMBOL_REFs. */ | |
1424 | default: | |
298e6adc | 1425 | gcc_unreachable (); |
9ae8ffe7 JL |
1426 | } |
1427 | } | |
1428 | return 1; | |
1429 | } | |
1430 | ||
94f24ddc | 1431 | rtx |
4682ae04 | 1432 | find_base_term (rtx x) |
9ae8ffe7 | 1433 | { |
eab5c70a BS |
1434 | cselib_val *val; |
1435 | struct elt_loc_list *l; | |
1436 | ||
b949ea8b JW |
1437 | #if defined (FIND_BASE_TERM) |
1438 | /* Try machine-dependent ways to find the base term. */ | |
1439 | x = FIND_BASE_TERM (x); | |
1440 | #endif | |
1441 | ||
9ae8ffe7 JL |
1442 | switch (GET_CODE (x)) |
1443 | { | |
1444 | case REG: | |
1445 | return REG_BASE_VALUE (x); | |
1446 | ||
d288e53d DE |
1447 | case TRUNCATE: |
1448 | if (GET_MODE_SIZE (GET_MODE (x)) < GET_MODE_SIZE (Pmode)) | |
ca7fd9cd | 1449 | return 0; |
d288e53d | 1450 | /* Fall through. */ |
9ae8ffe7 | 1451 | case HIGH: |
6d849a2a JL |
1452 | case PRE_INC: |
1453 | case PRE_DEC: | |
1454 | case POST_INC: | |
1455 | case POST_DEC: | |
d288e53d DE |
1456 | case PRE_MODIFY: |
1457 | case POST_MODIFY: | |
6d849a2a JL |
1458 | return find_base_term (XEXP (x, 0)); |
1459 | ||
1abade85 RK |
1460 | case ZERO_EXTEND: |
1461 | case SIGN_EXTEND: /* Used for Alpha/NT pointers */ | |
1462 | { | |
1463 | rtx temp = find_base_term (XEXP (x, 0)); | |
1464 | ||
5ae6cd0d | 1465 | if (temp != 0 && CONSTANT_P (temp)) |
1abade85 | 1466 | temp = convert_memory_address (Pmode, temp); |
1abade85 RK |
1467 | |
1468 | return temp; | |
1469 | } | |
1470 | ||
eab5c70a BS |
1471 | case VALUE: |
1472 | val = CSELIB_VAL_PTR (x); | |
40e02b4a JH |
1473 | if (!val) |
1474 | return 0; | |
eab5c70a BS |
1475 | for (l = val->locs; l; l = l->next) |
1476 | if ((x = find_base_term (l->loc)) != 0) | |
1477 | return x; | |
1478 | return 0; | |
1479 | ||
023f059b JJ |
1480 | case LO_SUM: |
1481 | /* The standard form is (lo_sum reg sym) so look only at the | |
1482 | second operand. */ | |
1483 | return find_base_term (XEXP (x, 1)); | |
1484 | ||
9ae8ffe7 JL |
1485 | case CONST: |
1486 | x = XEXP (x, 0); | |
1487 | if (GET_CODE (x) != PLUS && GET_CODE (x) != MINUS) | |
1488 | return 0; | |
938d968e | 1489 | /* Fall through. */ |
9ae8ffe7 JL |
1490 | case PLUS: |
1491 | case MINUS: | |
1492 | { | |
3c567fae JL |
1493 | rtx tmp1 = XEXP (x, 0); |
1494 | rtx tmp2 = XEXP (x, 1); | |
1495 | ||
f5143c46 | 1496 | /* This is a little bit tricky since we have to determine which of |
3c567fae JL |
1497 | the two operands represents the real base address. Otherwise this |
1498 | routine may return the index register instead of the base register. | |
1499 | ||
1500 | That may cause us to believe no aliasing was possible, when in | |
1501 | fact aliasing is possible. | |
1502 | ||
1503 | We use a few simple tests to guess the base register. Additional | |
1504 | tests can certainly be added. For example, if one of the operands | |
1505 | is a shift or multiply, then it must be the index register and the | |
1506 | other operand is the base register. */ | |
ca7fd9cd | 1507 | |
b949ea8b JW |
1508 | if (tmp1 == pic_offset_table_rtx && CONSTANT_P (tmp2)) |
1509 | return find_base_term (tmp2); | |
1510 | ||
3c567fae JL |
1511 | /* If either operand is known to be a pointer, then use it |
1512 | to determine the base term. */ | |
3502dc9c | 1513 | if (REG_P (tmp1) && REG_POINTER (tmp1)) |
7eba2d1f LM |
1514 | { |
1515 | rtx base = find_base_term (tmp1); | |
1516 | if (base) | |
1517 | return base; | |
1518 | } | |
3c567fae | 1519 | |
3502dc9c | 1520 | if (REG_P (tmp2) && REG_POINTER (tmp2)) |
7eba2d1f LM |
1521 | { |
1522 | rtx base = find_base_term (tmp2); | |
1523 | if (base) | |
1524 | return base; | |
1525 | } | |
3c567fae JL |
1526 | |
1527 | /* Neither operand was known to be a pointer. Go ahead and find the | |
1528 | base term for both operands. */ | |
1529 | tmp1 = find_base_term (tmp1); | |
1530 | tmp2 = find_base_term (tmp2); | |
1531 | ||
1532 | /* If either base term is named object or a special address | |
1533 | (like an argument or stack reference), then use it for the | |
1534 | base term. */ | |
d4b60170 | 1535 | if (tmp1 != 0 |
3c567fae JL |
1536 | && (GET_CODE (tmp1) == SYMBOL_REF |
1537 | || GET_CODE (tmp1) == LABEL_REF | |
1538 | || (GET_CODE (tmp1) == ADDRESS | |
1539 | && GET_MODE (tmp1) != VOIDmode))) | |
1540 | return tmp1; | |
1541 | ||
d4b60170 | 1542 | if (tmp2 != 0 |
3c567fae JL |
1543 | && (GET_CODE (tmp2) == SYMBOL_REF |
1544 | || GET_CODE (tmp2) == LABEL_REF | |
1545 | || (GET_CODE (tmp2) == ADDRESS | |
1546 | && GET_MODE (tmp2) != VOIDmode))) | |
1547 | return tmp2; | |
1548 | ||
1549 | /* We could not determine which of the two operands was the | |
1550 | base register and which was the index. So we can determine | |
1551 | nothing from the base alias check. */ | |
1552 | return 0; | |
9ae8ffe7 JL |
1553 | } |
1554 | ||
1555 | case AND: | |
481683e1 | 1556 | if (CONST_INT_P (XEXP (x, 1)) && INTVAL (XEXP (x, 1)) != 0) |
d288e53d | 1557 | return find_base_term (XEXP (x, 0)); |
9ae8ffe7 JL |
1558 | return 0; |
1559 | ||
1560 | case SYMBOL_REF: | |
1561 | case LABEL_REF: | |
1562 | return x; | |
1563 | ||
1564 | default: | |
1565 | return 0; | |
1566 | } | |
1567 | } | |
1568 | ||
1569 | /* Return 0 if the addresses X and Y are known to point to different | |
1570 | objects, 1 if they might be pointers to the same object. */ | |
1571 | ||
1572 | static int | |
4682ae04 AJ |
1573 | base_alias_check (rtx x, rtx y, enum machine_mode x_mode, |
1574 | enum machine_mode y_mode) | |
9ae8ffe7 JL |
1575 | { |
1576 | rtx x_base = find_base_term (x); | |
1577 | rtx y_base = find_base_term (y); | |
1578 | ||
1c72c7f6 JC |
1579 | /* If the address itself has no known base see if a known equivalent |
1580 | value has one. If either address still has no known base, nothing | |
1581 | is known about aliasing. */ | |
1582 | if (x_base == 0) | |
1583 | { | |
1584 | rtx x_c; | |
d4b60170 | 1585 | |
1c72c7f6 JC |
1586 | if (! flag_expensive_optimizations || (x_c = canon_rtx (x)) == x) |
1587 | return 1; | |
d4b60170 | 1588 | |
1c72c7f6 JC |
1589 | x_base = find_base_term (x_c); |
1590 | if (x_base == 0) | |
1591 | return 1; | |
1592 | } | |
9ae8ffe7 | 1593 | |
1c72c7f6 JC |
1594 | if (y_base == 0) |
1595 | { | |
1596 | rtx y_c; | |
1597 | if (! flag_expensive_optimizations || (y_c = canon_rtx (y)) == y) | |
1598 | return 1; | |
d4b60170 | 1599 | |
1c72c7f6 JC |
1600 | y_base = find_base_term (y_c); |
1601 | if (y_base == 0) | |
1602 | return 1; | |
1603 | } | |
1604 | ||
1605 | /* If the base addresses are equal nothing is known about aliasing. */ | |
1606 | if (rtx_equal_p (x_base, y_base)) | |
9ae8ffe7 JL |
1607 | return 1; |
1608 | ||
435da628 UB |
1609 | /* The base addresses are different expressions. If they are not accessed |
1610 | via AND, there is no conflict. We can bring knowledge of object | |
1611 | alignment into play here. For example, on alpha, "char a, b;" can | |
1612 | alias one another, though "char a; long b;" cannot. AND addesses may | |
1613 | implicitly alias surrounding objects; i.e. unaligned access in DImode | |
1614 | via AND address can alias all surrounding object types except those | |
1615 | with aligment 8 or higher. */ | |
1616 | if (GET_CODE (x) == AND && GET_CODE (y) == AND) | |
1617 | return 1; | |
1618 | if (GET_CODE (x) == AND | |
481683e1 | 1619 | && (!CONST_INT_P (XEXP (x, 1)) |
435da628 UB |
1620 | || (int) GET_MODE_UNIT_SIZE (y_mode) < -INTVAL (XEXP (x, 1)))) |
1621 | return 1; | |
1622 | if (GET_CODE (y) == AND | |
481683e1 | 1623 | && (!CONST_INT_P (XEXP (y, 1)) |
435da628 UB |
1624 | || (int) GET_MODE_UNIT_SIZE (x_mode) < -INTVAL (XEXP (y, 1)))) |
1625 | return 1; | |
1626 | ||
1627 | /* Differing symbols not accessed via AND never alias. */ | |
9ae8ffe7 | 1628 | if (GET_CODE (x_base) != ADDRESS && GET_CODE (y_base) != ADDRESS) |
435da628 | 1629 | return 0; |
9ae8ffe7 JL |
1630 | |
1631 | /* If one address is a stack reference there can be no alias: | |
1632 | stack references using different base registers do not alias, | |
1633 | a stack reference can not alias a parameter, and a stack reference | |
1634 | can not alias a global. */ | |
1635 | if ((GET_CODE (x_base) == ADDRESS && GET_MODE (x_base) == Pmode) | |
1636 | || (GET_CODE (y_base) == ADDRESS && GET_MODE (y_base) == Pmode)) | |
1637 | return 0; | |
1638 | ||
1639 | if (! flag_argument_noalias) | |
1640 | return 1; | |
1641 | ||
1642 | if (flag_argument_noalias > 1) | |
1643 | return 0; | |
1644 | ||
ec5c56db | 1645 | /* Weak noalias assertion (arguments are distinct, but may match globals). */ |
9ae8ffe7 JL |
1646 | return ! (GET_MODE (x_base) == VOIDmode && GET_MODE (y_base) == VOIDmode); |
1647 | } | |
1648 | ||
eab5c70a BS |
1649 | /* Convert the address X into something we can use. This is done by returning |
1650 | it unchanged unless it is a value; in the latter case we call cselib to get | |
1651 | a more useful rtx. */ | |
3bdf5ad1 | 1652 | |
a13d4ebf | 1653 | rtx |
4682ae04 | 1654 | get_addr (rtx x) |
eab5c70a BS |
1655 | { |
1656 | cselib_val *v; | |
1657 | struct elt_loc_list *l; | |
1658 | ||
1659 | if (GET_CODE (x) != VALUE) | |
1660 | return x; | |
1661 | v = CSELIB_VAL_PTR (x); | |
40e02b4a JH |
1662 | if (v) |
1663 | { | |
1664 | for (l = v->locs; l; l = l->next) | |
1665 | if (CONSTANT_P (l->loc)) | |
1666 | return l->loc; | |
1667 | for (l = v->locs; l; l = l->next) | |
3c0cb5de | 1668 | if (!REG_P (l->loc) && !MEM_P (l->loc)) |
40e02b4a JH |
1669 | return l->loc; |
1670 | if (v->locs) | |
1671 | return v->locs->loc; | |
1672 | } | |
eab5c70a BS |
1673 | return x; |
1674 | } | |
1675 | ||
39cec1ac MH |
1676 | /* Return the address of the (N_REFS + 1)th memory reference to ADDR |
1677 | where SIZE is the size in bytes of the memory reference. If ADDR | |
1678 | is not modified by the memory reference then ADDR is returned. */ | |
1679 | ||
04e2b4d3 | 1680 | static rtx |
4682ae04 | 1681 | addr_side_effect_eval (rtx addr, int size, int n_refs) |
39cec1ac MH |
1682 | { |
1683 | int offset = 0; | |
ca7fd9cd | 1684 | |
39cec1ac MH |
1685 | switch (GET_CODE (addr)) |
1686 | { | |
1687 | case PRE_INC: | |
1688 | offset = (n_refs + 1) * size; | |
1689 | break; | |
1690 | case PRE_DEC: | |
1691 | offset = -(n_refs + 1) * size; | |
1692 | break; | |
1693 | case POST_INC: | |
1694 | offset = n_refs * size; | |
1695 | break; | |
1696 | case POST_DEC: | |
1697 | offset = -n_refs * size; | |
1698 | break; | |
1699 | ||
1700 | default: | |
1701 | return addr; | |
1702 | } | |
ca7fd9cd | 1703 | |
39cec1ac | 1704 | if (offset) |
45183e03 | 1705 | addr = gen_rtx_PLUS (GET_MODE (addr), XEXP (addr, 0), |
c22cacf3 | 1706 | GEN_INT (offset)); |
39cec1ac MH |
1707 | else |
1708 | addr = XEXP (addr, 0); | |
45183e03 | 1709 | addr = canon_rtx (addr); |
39cec1ac MH |
1710 | |
1711 | return addr; | |
1712 | } | |
1713 | ||
9ae8ffe7 JL |
1714 | /* Return nonzero if X and Y (memory addresses) could reference the |
1715 | same location in memory. C is an offset accumulator. When | |
1716 | C is nonzero, we are testing aliases between X and Y + C. | |
1717 | XSIZE is the size in bytes of the X reference, | |
1718 | similarly YSIZE is the size in bytes for Y. | |
45183e03 | 1719 | Expect that canon_rtx has been already called for X and Y. |
9ae8ffe7 JL |
1720 | |
1721 | If XSIZE or YSIZE is zero, we do not know the amount of memory being | |
1722 | referenced (the reference was BLKmode), so make the most pessimistic | |
1723 | assumptions. | |
1724 | ||
c02f035f RH |
1725 | If XSIZE or YSIZE is negative, we may access memory outside the object |
1726 | being referenced as a side effect. This can happen when using AND to | |
1727 | align memory references, as is done on the Alpha. | |
1728 | ||
9ae8ffe7 | 1729 | Nice to notice that varying addresses cannot conflict with fp if no |
0211b6ab | 1730 | local variables had their addresses taken, but that's too hard now. */ |
9ae8ffe7 | 1731 | |
9ae8ffe7 | 1732 | static int |
4682ae04 | 1733 | memrefs_conflict_p (int xsize, rtx x, int ysize, rtx y, HOST_WIDE_INT c) |
9ae8ffe7 | 1734 | { |
eab5c70a BS |
1735 | if (GET_CODE (x) == VALUE) |
1736 | x = get_addr (x); | |
1737 | if (GET_CODE (y) == VALUE) | |
1738 | y = get_addr (y); | |
9ae8ffe7 JL |
1739 | if (GET_CODE (x) == HIGH) |
1740 | x = XEXP (x, 0); | |
1741 | else if (GET_CODE (x) == LO_SUM) | |
1742 | x = XEXP (x, 1); | |
1743 | else | |
45183e03 | 1744 | x = addr_side_effect_eval (x, xsize, 0); |
9ae8ffe7 JL |
1745 | if (GET_CODE (y) == HIGH) |
1746 | y = XEXP (y, 0); | |
1747 | else if (GET_CODE (y) == LO_SUM) | |
1748 | y = XEXP (y, 1); | |
1749 | else | |
45183e03 | 1750 | y = addr_side_effect_eval (y, ysize, 0); |
9ae8ffe7 JL |
1751 | |
1752 | if (rtx_equal_for_memref_p (x, y)) | |
1753 | { | |
c02f035f | 1754 | if (xsize <= 0 || ysize <= 0) |
9ae8ffe7 JL |
1755 | return 1; |
1756 | if (c >= 0 && xsize > c) | |
1757 | return 1; | |
1758 | if (c < 0 && ysize+c > 0) | |
1759 | return 1; | |
1760 | return 0; | |
1761 | } | |
1762 | ||
6e73e666 JC |
1763 | /* This code used to check for conflicts involving stack references and |
1764 | globals but the base address alias code now handles these cases. */ | |
9ae8ffe7 JL |
1765 | |
1766 | if (GET_CODE (x) == PLUS) | |
1767 | { | |
1768 | /* The fact that X is canonicalized means that this | |
1769 | PLUS rtx is canonicalized. */ | |
1770 | rtx x0 = XEXP (x, 0); | |
1771 | rtx x1 = XEXP (x, 1); | |
1772 | ||
1773 | if (GET_CODE (y) == PLUS) | |
1774 | { | |
1775 | /* The fact that Y is canonicalized means that this | |
1776 | PLUS rtx is canonicalized. */ | |
1777 | rtx y0 = XEXP (y, 0); | |
1778 | rtx y1 = XEXP (y, 1); | |
1779 | ||
1780 | if (rtx_equal_for_memref_p (x1, y1)) | |
1781 | return memrefs_conflict_p (xsize, x0, ysize, y0, c); | |
1782 | if (rtx_equal_for_memref_p (x0, y0)) | |
1783 | return memrefs_conflict_p (xsize, x1, ysize, y1, c); | |
481683e1 | 1784 | if (CONST_INT_P (x1)) |
63be02db | 1785 | { |
481683e1 | 1786 | if (CONST_INT_P (y1)) |
63be02db JM |
1787 | return memrefs_conflict_p (xsize, x0, ysize, y0, |
1788 | c - INTVAL (x1) + INTVAL (y1)); | |
1789 | else | |
1790 | return memrefs_conflict_p (xsize, x0, ysize, y, | |
1791 | c - INTVAL (x1)); | |
1792 | } | |
481683e1 | 1793 | else if (CONST_INT_P (y1)) |
9ae8ffe7 JL |
1794 | return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1)); |
1795 | ||
6e73e666 | 1796 | return 1; |
9ae8ffe7 | 1797 | } |
481683e1 | 1798 | else if (CONST_INT_P (x1)) |
9ae8ffe7 JL |
1799 | return memrefs_conflict_p (xsize, x0, ysize, y, c - INTVAL (x1)); |
1800 | } | |
1801 | else if (GET_CODE (y) == PLUS) | |
1802 | { | |
1803 | /* The fact that Y is canonicalized means that this | |
1804 | PLUS rtx is canonicalized. */ | |
1805 | rtx y0 = XEXP (y, 0); | |
1806 | rtx y1 = XEXP (y, 1); | |
1807 | ||
481683e1 | 1808 | if (CONST_INT_P (y1)) |
9ae8ffe7 JL |
1809 | return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1)); |
1810 | else | |
1811 | return 1; | |
1812 | } | |
1813 | ||
1814 | if (GET_CODE (x) == GET_CODE (y)) | |
1815 | switch (GET_CODE (x)) | |
1816 | { | |
1817 | case MULT: | |
1818 | { | |
1819 | /* Handle cases where we expect the second operands to be the | |
1820 | same, and check only whether the first operand would conflict | |
1821 | or not. */ | |
1822 | rtx x0, y0; | |
1823 | rtx x1 = canon_rtx (XEXP (x, 1)); | |
1824 | rtx y1 = canon_rtx (XEXP (y, 1)); | |
1825 | if (! rtx_equal_for_memref_p (x1, y1)) | |
1826 | return 1; | |
1827 | x0 = canon_rtx (XEXP (x, 0)); | |
1828 | y0 = canon_rtx (XEXP (y, 0)); | |
1829 | if (rtx_equal_for_memref_p (x0, y0)) | |
1830 | return (xsize == 0 || ysize == 0 | |
1831 | || (c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)); | |
1832 | ||
1833 | /* Can't properly adjust our sizes. */ | |
481683e1 | 1834 | if (!CONST_INT_P (x1)) |
9ae8ffe7 JL |
1835 | return 1; |
1836 | xsize /= INTVAL (x1); | |
1837 | ysize /= INTVAL (x1); | |
1838 | c /= INTVAL (x1); | |
1839 | return memrefs_conflict_p (xsize, x0, ysize, y0, c); | |
1840 | } | |
1d300e19 KG |
1841 | |
1842 | default: | |
1843 | break; | |
9ae8ffe7 JL |
1844 | } |
1845 | ||
1846 | /* Treat an access through an AND (e.g. a subword access on an Alpha) | |
ca7fd9cd | 1847 | as an access with indeterminate size. Assume that references |
56ee9281 RH |
1848 | besides AND are aligned, so if the size of the other reference is |
1849 | at least as large as the alignment, assume no other overlap. */ | |
481683e1 | 1850 | if (GET_CODE (x) == AND && CONST_INT_P (XEXP (x, 1))) |
56ee9281 | 1851 | { |
02e3377d | 1852 | if (GET_CODE (y) == AND || ysize < -INTVAL (XEXP (x, 1))) |
56ee9281 | 1853 | xsize = -1; |
45183e03 | 1854 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), ysize, y, c); |
56ee9281 | 1855 | } |
481683e1 | 1856 | if (GET_CODE (y) == AND && CONST_INT_P (XEXP (y, 1))) |
c02f035f | 1857 | { |
56ee9281 | 1858 | /* ??? If we are indexing far enough into the array/structure, we |
ca7fd9cd | 1859 | may yet be able to determine that we can not overlap. But we |
c02f035f | 1860 | also need to that we are far enough from the end not to overlap |
56ee9281 | 1861 | a following reference, so we do nothing with that for now. */ |
02e3377d | 1862 | if (GET_CODE (x) == AND || xsize < -INTVAL (XEXP (y, 1))) |
56ee9281 | 1863 | ysize = -1; |
45183e03 | 1864 | return memrefs_conflict_p (xsize, x, ysize, canon_rtx (XEXP (y, 0)), c); |
c02f035f | 1865 | } |
9ae8ffe7 JL |
1866 | |
1867 | if (CONSTANT_P (x)) | |
1868 | { | |
481683e1 | 1869 | if (CONST_INT_P (x) && CONST_INT_P (y)) |
9ae8ffe7 JL |
1870 | { |
1871 | c += (INTVAL (y) - INTVAL (x)); | |
c02f035f | 1872 | return (xsize <= 0 || ysize <= 0 |
9ae8ffe7 JL |
1873 | || (c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)); |
1874 | } | |
1875 | ||
1876 | if (GET_CODE (x) == CONST) | |
1877 | { | |
1878 | if (GET_CODE (y) == CONST) | |
1879 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), | |
1880 | ysize, canon_rtx (XEXP (y, 0)), c); | |
1881 | else | |
1882 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), | |
1883 | ysize, y, c); | |
1884 | } | |
1885 | if (GET_CODE (y) == CONST) | |
1886 | return memrefs_conflict_p (xsize, x, ysize, | |
1887 | canon_rtx (XEXP (y, 0)), c); | |
1888 | ||
1889 | if (CONSTANT_P (y)) | |
b949ea8b | 1890 | return (xsize <= 0 || ysize <= 0 |
c02f035f | 1891 | || (rtx_equal_for_memref_p (x, y) |
b949ea8b | 1892 | && ((c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)))); |
9ae8ffe7 JL |
1893 | |
1894 | return 1; | |
1895 | } | |
1896 | return 1; | |
1897 | } | |
1898 | ||
1899 | /* Functions to compute memory dependencies. | |
1900 | ||
1901 | Since we process the insns in execution order, we can build tables | |
1902 | to keep track of what registers are fixed (and not aliased), what registers | |
1903 | are varying in known ways, and what registers are varying in unknown | |
1904 | ways. | |
1905 | ||
1906 | If both memory references are volatile, then there must always be a | |
1907 | dependence between the two references, since their order can not be | |
1908 | changed. A volatile and non-volatile reference can be interchanged | |
ca7fd9cd | 1909 | though. |
9ae8ffe7 | 1910 | |
dc1618bc RK |
1911 | A MEM_IN_STRUCT reference at a non-AND varying address can never |
1912 | conflict with a non-MEM_IN_STRUCT reference at a fixed address. We | |
1913 | also must allow AND addresses, because they may generate accesses | |
1914 | outside the object being referenced. This is used to generate | |
1915 | aligned addresses from unaligned addresses, for instance, the alpha | |
1916 | storeqi_unaligned pattern. */ | |
9ae8ffe7 JL |
1917 | |
1918 | /* Read dependence: X is read after read in MEM takes place. There can | |
1919 | only be a dependence here if both reads are volatile. */ | |
1920 | ||
1921 | int | |
4f588890 | 1922 | read_dependence (const_rtx mem, const_rtx x) |
9ae8ffe7 JL |
1923 | { |
1924 | return MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem); | |
1925 | } | |
1926 | ||
c6df88cb MM |
1927 | /* Returns MEM1 if and only if MEM1 is a scalar at a fixed address and |
1928 | MEM2 is a reference to a structure at a varying address, or returns | |
1929 | MEM2 if vice versa. Otherwise, returns NULL_RTX. If a non-NULL | |
1930 | value is returned MEM1 and MEM2 can never alias. VARIES_P is used | |
1931 | to decide whether or not an address may vary; it should return | |
eab5c70a BS |
1932 | nonzero whenever variation is possible. |
1933 | MEM1_ADDR and MEM2_ADDR are the addresses of MEM1 and MEM2. */ | |
ca7fd9cd | 1934 | |
4f588890 KG |
1935 | static const_rtx |
1936 | fixed_scalar_and_varying_struct_p (const_rtx mem1, const_rtx mem2, rtx mem1_addr, | |
4682ae04 | 1937 | rtx mem2_addr, |
4f588890 | 1938 | bool (*varies_p) (const_rtx, bool)) |
ca7fd9cd | 1939 | { |
3e0abe15 GK |
1940 | if (! flag_strict_aliasing) |
1941 | return NULL_RTX; | |
1942 | ||
afa8f0fb AP |
1943 | if (MEM_ALIAS_SET (mem2) |
1944 | && MEM_SCALAR_P (mem1) && MEM_IN_STRUCT_P (mem2) | |
e38fe8e0 | 1945 | && !varies_p (mem1_addr, 1) && varies_p (mem2_addr, 1)) |
c6df88cb MM |
1946 | /* MEM1 is a scalar at a fixed address; MEM2 is a struct at a |
1947 | varying address. */ | |
1948 | return mem1; | |
1949 | ||
afa8f0fb AP |
1950 | if (MEM_ALIAS_SET (mem1) |
1951 | && MEM_IN_STRUCT_P (mem1) && MEM_SCALAR_P (mem2) | |
e38fe8e0 | 1952 | && varies_p (mem1_addr, 1) && !varies_p (mem2_addr, 1)) |
c6df88cb MM |
1953 | /* MEM2 is a scalar at a fixed address; MEM1 is a struct at a |
1954 | varying address. */ | |
1955 | return mem2; | |
1956 | ||
1957 | return NULL_RTX; | |
1958 | } | |
1959 | ||
1960 | /* Returns nonzero if something about the mode or address format MEM1 | |
1961 | indicates that it might well alias *anything*. */ | |
1962 | ||
2c72b78f | 1963 | static int |
4f588890 | 1964 | aliases_everything_p (const_rtx mem) |
c6df88cb | 1965 | { |
c6df88cb | 1966 | if (GET_CODE (XEXP (mem, 0)) == AND) |
35fd3193 | 1967 | /* If the address is an AND, it's very hard to know at what it is |
c6df88cb MM |
1968 | actually pointing. */ |
1969 | return 1; | |
ca7fd9cd | 1970 | |
c6df88cb MM |
1971 | return 0; |
1972 | } | |
1973 | ||
998d7deb RH |
1974 | /* Return true if we can determine that the fields referenced cannot |
1975 | overlap for any pair of objects. */ | |
1976 | ||
1977 | static bool | |
4f588890 | 1978 | nonoverlapping_component_refs_p (const_tree x, const_tree y) |
998d7deb | 1979 | { |
4f588890 | 1980 | const_tree fieldx, fieldy, typex, typey, orig_y; |
998d7deb RH |
1981 | |
1982 | do | |
1983 | { | |
1984 | /* The comparison has to be done at a common type, since we don't | |
d6a7951f | 1985 | know how the inheritance hierarchy works. */ |
998d7deb RH |
1986 | orig_y = y; |
1987 | do | |
1988 | { | |
1989 | fieldx = TREE_OPERAND (x, 1); | |
c05a0766 | 1990 | typex = TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (fieldx)); |
998d7deb RH |
1991 | |
1992 | y = orig_y; | |
1993 | do | |
1994 | { | |
1995 | fieldy = TREE_OPERAND (y, 1); | |
c05a0766 | 1996 | typey = TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (fieldy)); |
998d7deb RH |
1997 | |
1998 | if (typex == typey) | |
1999 | goto found; | |
2000 | ||
2001 | y = TREE_OPERAND (y, 0); | |
2002 | } | |
2003 | while (y && TREE_CODE (y) == COMPONENT_REF); | |
2004 | ||
2005 | x = TREE_OPERAND (x, 0); | |
2006 | } | |
2007 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
998d7deb | 2008 | /* Never found a common type. */ |
c05a0766 | 2009 | return false; |
998d7deb RH |
2010 | |
2011 | found: | |
2012 | /* If we're left with accessing different fields of a structure, | |
2013 | then no overlap. */ | |
2014 | if (TREE_CODE (typex) == RECORD_TYPE | |
2015 | && fieldx != fieldy) | |
2016 | return true; | |
2017 | ||
2018 | /* The comparison on the current field failed. If we're accessing | |
2019 | a very nested structure, look at the next outer level. */ | |
2020 | x = TREE_OPERAND (x, 0); | |
2021 | y = TREE_OPERAND (y, 0); | |
2022 | } | |
2023 | while (x && y | |
2024 | && TREE_CODE (x) == COMPONENT_REF | |
2025 | && TREE_CODE (y) == COMPONENT_REF); | |
ca7fd9cd | 2026 | |
998d7deb RH |
2027 | return false; |
2028 | } | |
2029 | ||
2030 | /* Look at the bottom of the COMPONENT_REF list for a DECL, and return it. */ | |
2031 | ||
2032 | static tree | |
4682ae04 | 2033 | decl_for_component_ref (tree x) |
998d7deb RH |
2034 | { |
2035 | do | |
2036 | { | |
2037 | x = TREE_OPERAND (x, 0); | |
2038 | } | |
2039 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
2040 | ||
2041 | return x && DECL_P (x) ? x : NULL_TREE; | |
2042 | } | |
2043 | ||
2044 | /* Walk up the COMPONENT_REF list and adjust OFFSET to compensate for the | |
2045 | offset of the field reference. */ | |
2046 | ||
2047 | static rtx | |
4682ae04 | 2048 | adjust_offset_for_component_ref (tree x, rtx offset) |
998d7deb RH |
2049 | { |
2050 | HOST_WIDE_INT ioffset; | |
2051 | ||
2052 | if (! offset) | |
2053 | return NULL_RTX; | |
2054 | ||
2055 | ioffset = INTVAL (offset); | |
ca7fd9cd | 2056 | do |
998d7deb | 2057 | { |
44de5aeb | 2058 | tree offset = component_ref_field_offset (x); |
998d7deb RH |
2059 | tree field = TREE_OPERAND (x, 1); |
2060 | ||
44de5aeb | 2061 | if (! host_integerp (offset, 1)) |
998d7deb | 2062 | return NULL_RTX; |
44de5aeb | 2063 | ioffset += (tree_low_cst (offset, 1) |
998d7deb RH |
2064 | + (tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1) |
2065 | / BITS_PER_UNIT)); | |
2066 | ||
2067 | x = TREE_OPERAND (x, 0); | |
2068 | } | |
2069 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
2070 | ||
2071 | return GEN_INT (ioffset); | |
2072 | } | |
2073 | ||
95bd1dd7 | 2074 | /* Return nonzero if we can determine the exprs corresponding to memrefs |
a4311dfe RK |
2075 | X and Y and they do not overlap. */ |
2076 | ||
2e4e39f6 | 2077 | int |
4f588890 | 2078 | nonoverlapping_memrefs_p (const_rtx x, const_rtx y) |
a4311dfe | 2079 | { |
998d7deb | 2080 | tree exprx = MEM_EXPR (x), expry = MEM_EXPR (y); |
a4311dfe RK |
2081 | rtx rtlx, rtly; |
2082 | rtx basex, basey; | |
998d7deb | 2083 | rtx moffsetx, moffsety; |
a4311dfe RK |
2084 | HOST_WIDE_INT offsetx = 0, offsety = 0, sizex, sizey, tem; |
2085 | ||
998d7deb RH |
2086 | /* Unless both have exprs, we can't tell anything. */ |
2087 | if (exprx == 0 || expry == 0) | |
2088 | return 0; | |
c22cacf3 | 2089 | |
998d7deb RH |
2090 | /* If both are field references, we may be able to determine something. */ |
2091 | if (TREE_CODE (exprx) == COMPONENT_REF | |
2092 | && TREE_CODE (expry) == COMPONENT_REF | |
2093 | && nonoverlapping_component_refs_p (exprx, expry)) | |
2094 | return 1; | |
2095 | ||
c22cacf3 | 2096 | |
998d7deb RH |
2097 | /* If the field reference test failed, look at the DECLs involved. */ |
2098 | moffsetx = MEM_OFFSET (x); | |
2099 | if (TREE_CODE (exprx) == COMPONENT_REF) | |
2100 | { | |
ea900239 DB |
2101 | if (TREE_CODE (expry) == VAR_DECL |
2102 | && POINTER_TYPE_P (TREE_TYPE (expry))) | |
2103 | { | |
2104 | tree field = TREE_OPERAND (exprx, 1); | |
2105 | tree fieldcontext = DECL_FIELD_CONTEXT (field); | |
2106 | if (ipa_type_escape_field_does_not_clobber_p (fieldcontext, | |
2107 | TREE_TYPE (field))) | |
c22cacf3 | 2108 | return 1; |
ea900239 DB |
2109 | } |
2110 | { | |
2111 | tree t = decl_for_component_ref (exprx); | |
2112 | if (! t) | |
2113 | return 0; | |
2114 | moffsetx = adjust_offset_for_component_ref (exprx, moffsetx); | |
2115 | exprx = t; | |
2116 | } | |
998d7deb | 2117 | } |
1b096a0a | 2118 | else if (INDIRECT_REF_P (exprx)) |
c67a1cf6 RH |
2119 | { |
2120 | exprx = TREE_OPERAND (exprx, 0); | |
2121 | if (flag_argument_noalias < 2 | |
2122 | || TREE_CODE (exprx) != PARM_DECL) | |
2123 | return 0; | |
2124 | } | |
2125 | ||
998d7deb RH |
2126 | moffsety = MEM_OFFSET (y); |
2127 | if (TREE_CODE (expry) == COMPONENT_REF) | |
2128 | { | |
ea900239 DB |
2129 | if (TREE_CODE (exprx) == VAR_DECL |
2130 | && POINTER_TYPE_P (TREE_TYPE (exprx))) | |
2131 | { | |
2132 | tree field = TREE_OPERAND (expry, 1); | |
2133 | tree fieldcontext = DECL_FIELD_CONTEXT (field); | |
2134 | if (ipa_type_escape_field_does_not_clobber_p (fieldcontext, | |
2135 | TREE_TYPE (field))) | |
c22cacf3 | 2136 | return 1; |
ea900239 DB |
2137 | } |
2138 | { | |
2139 | tree t = decl_for_component_ref (expry); | |
2140 | if (! t) | |
2141 | return 0; | |
2142 | moffsety = adjust_offset_for_component_ref (expry, moffsety); | |
2143 | expry = t; | |
2144 | } | |
998d7deb | 2145 | } |
1b096a0a | 2146 | else if (INDIRECT_REF_P (expry)) |
c67a1cf6 RH |
2147 | { |
2148 | expry = TREE_OPERAND (expry, 0); | |
2149 | if (flag_argument_noalias < 2 | |
2150 | || TREE_CODE (expry) != PARM_DECL) | |
2151 | return 0; | |
2152 | } | |
998d7deb RH |
2153 | |
2154 | if (! DECL_P (exprx) || ! DECL_P (expry)) | |
a4311dfe RK |
2155 | return 0; |
2156 | ||
998d7deb RH |
2157 | rtlx = DECL_RTL (exprx); |
2158 | rtly = DECL_RTL (expry); | |
a4311dfe | 2159 | |
1edcd60b RK |
2160 | /* If either RTL is not a MEM, it must be a REG or CONCAT, meaning they |
2161 | can't overlap unless they are the same because we never reuse that part | |
2162 | of the stack frame used for locals for spilled pseudos. */ | |
3c0cb5de | 2163 | if ((!MEM_P (rtlx) || !MEM_P (rtly)) |
1edcd60b | 2164 | && ! rtx_equal_p (rtlx, rtly)) |
a4311dfe RK |
2165 | return 1; |
2166 | ||
2167 | /* Get the base and offsets of both decls. If either is a register, we | |
2168 | know both are and are the same, so use that as the base. The only | |
2169 | we can avoid overlap is if we can deduce that they are nonoverlapping | |
2170 | pieces of that decl, which is very rare. */ | |
3c0cb5de | 2171 | basex = MEM_P (rtlx) ? XEXP (rtlx, 0) : rtlx; |
481683e1 | 2172 | if (GET_CODE (basex) == PLUS && CONST_INT_P (XEXP (basex, 1))) |
a4311dfe RK |
2173 | offsetx = INTVAL (XEXP (basex, 1)), basex = XEXP (basex, 0); |
2174 | ||
3c0cb5de | 2175 | basey = MEM_P (rtly) ? XEXP (rtly, 0) : rtly; |
481683e1 | 2176 | if (GET_CODE (basey) == PLUS && CONST_INT_P (XEXP (basey, 1))) |
a4311dfe RK |
2177 | offsety = INTVAL (XEXP (basey, 1)), basey = XEXP (basey, 0); |
2178 | ||
d746694a | 2179 | /* If the bases are different, we know they do not overlap if both |
ca7fd9cd | 2180 | are constants or if one is a constant and the other a pointer into the |
d746694a RK |
2181 | stack frame. Otherwise a different base means we can't tell if they |
2182 | overlap or not. */ | |
2183 | if (! rtx_equal_p (basex, basey)) | |
ca7fd9cd KH |
2184 | return ((CONSTANT_P (basex) && CONSTANT_P (basey)) |
2185 | || (CONSTANT_P (basex) && REG_P (basey) | |
2186 | && REGNO_PTR_FRAME_P (REGNO (basey))) | |
2187 | || (CONSTANT_P (basey) && REG_P (basex) | |
2188 | && REGNO_PTR_FRAME_P (REGNO (basex)))); | |
a4311dfe | 2189 | |
3c0cb5de | 2190 | sizex = (!MEM_P (rtlx) ? (int) GET_MODE_SIZE (GET_MODE (rtlx)) |
a4311dfe RK |
2191 | : MEM_SIZE (rtlx) ? INTVAL (MEM_SIZE (rtlx)) |
2192 | : -1); | |
3c0cb5de | 2193 | sizey = (!MEM_P (rtly) ? (int) GET_MODE_SIZE (GET_MODE (rtly)) |
a4311dfe RK |
2194 | : MEM_SIZE (rtly) ? INTVAL (MEM_SIZE (rtly)) : |
2195 | -1); | |
2196 | ||
0af5bc3e RK |
2197 | /* If we have an offset for either memref, it can update the values computed |
2198 | above. */ | |
998d7deb RH |
2199 | if (moffsetx) |
2200 | offsetx += INTVAL (moffsetx), sizex -= INTVAL (moffsetx); | |
2201 | if (moffsety) | |
2202 | offsety += INTVAL (moffsety), sizey -= INTVAL (moffsety); | |
a4311dfe | 2203 | |
0af5bc3e | 2204 | /* If a memref has both a size and an offset, we can use the smaller size. |
efc981bb | 2205 | We can't do this if the offset isn't known because we must view this |
0af5bc3e | 2206 | memref as being anywhere inside the DECL's MEM. */ |
998d7deb | 2207 | if (MEM_SIZE (x) && moffsetx) |
a4311dfe | 2208 | sizex = INTVAL (MEM_SIZE (x)); |
998d7deb | 2209 | if (MEM_SIZE (y) && moffsety) |
a4311dfe RK |
2210 | sizey = INTVAL (MEM_SIZE (y)); |
2211 | ||
2212 | /* Put the values of the memref with the lower offset in X's values. */ | |
2213 | if (offsetx > offsety) | |
2214 | { | |
2215 | tem = offsetx, offsetx = offsety, offsety = tem; | |
2216 | tem = sizex, sizex = sizey, sizey = tem; | |
2217 | } | |
2218 | ||
2219 | /* If we don't know the size of the lower-offset value, we can't tell | |
2220 | if they conflict. Otherwise, we do the test. */ | |
a6f7c915 | 2221 | return sizex >= 0 && offsety >= offsetx + sizex; |
a4311dfe RK |
2222 | } |
2223 | ||
9ae8ffe7 JL |
2224 | /* True dependence: X is read after store in MEM takes place. */ |
2225 | ||
2226 | int | |
4f588890 KG |
2227 | true_dependence (const_rtx mem, enum machine_mode mem_mode, const_rtx x, |
2228 | bool (*varies) (const_rtx, bool)) | |
9ae8ffe7 | 2229 | { |
b3694847 | 2230 | rtx x_addr, mem_addr; |
49982682 | 2231 | rtx base; |
9ae8ffe7 JL |
2232 | |
2233 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) | |
2234 | return 1; | |
2235 | ||
c4484b8f | 2236 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
ac3768f6 | 2237 | This is used in epilogue deallocation functions, and in cselib. */ |
c4484b8f RH |
2238 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) |
2239 | return 1; | |
2240 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
2241 | return 1; | |
9cd9e512 RH |
2242 | if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER |
2243 | || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER) | |
2244 | return 1; | |
c4484b8f | 2245 | |
41472af8 MM |
2246 | if (DIFFERENT_ALIAS_SETS_P (x, mem)) |
2247 | return 0; | |
2248 | ||
389fdba0 RH |
2249 | /* Read-only memory is by definition never modified, and therefore can't |
2250 | conflict with anything. We don't expect to find read-only set on MEM, | |
41806d92 | 2251 | but stupid user tricks can produce them, so don't die. */ |
389fdba0 | 2252 | if (MEM_READONLY_P (x)) |
9ae8ffe7 JL |
2253 | return 0; |
2254 | ||
a4311dfe RK |
2255 | if (nonoverlapping_memrefs_p (mem, x)) |
2256 | return 0; | |
2257 | ||
56ee9281 RH |
2258 | if (mem_mode == VOIDmode) |
2259 | mem_mode = GET_MODE (mem); | |
2260 | ||
eab5c70a BS |
2261 | x_addr = get_addr (XEXP (x, 0)); |
2262 | mem_addr = get_addr (XEXP (mem, 0)); | |
2263 | ||
55efb413 JW |
2264 | base = find_base_term (x_addr); |
2265 | if (base && (GET_CODE (base) == LABEL_REF | |
2266 | || (GET_CODE (base) == SYMBOL_REF | |
2267 | && CONSTANT_POOL_ADDRESS_P (base)))) | |
2268 | return 0; | |
2269 | ||
eab5c70a | 2270 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), mem_mode)) |
1c72c7f6 JC |
2271 | return 0; |
2272 | ||
eab5c70a BS |
2273 | x_addr = canon_rtx (x_addr); |
2274 | mem_addr = canon_rtx (mem_addr); | |
6e73e666 | 2275 | |
0211b6ab JW |
2276 | if (! memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr, |
2277 | SIZE_FOR_MODE (x), x_addr, 0)) | |
2278 | return 0; | |
2279 | ||
c6df88cb | 2280 | if (aliases_everything_p (x)) |
0211b6ab JW |
2281 | return 1; |
2282 | ||
f5143c46 | 2283 | /* We cannot use aliases_everything_p to test MEM, since we must look |
c6df88cb MM |
2284 | at MEM_MODE, rather than GET_MODE (MEM). */ |
2285 | if (mem_mode == QImode || GET_CODE (mem_addr) == AND) | |
a13d4ebf AM |
2286 | return 1; |
2287 | ||
2288 | /* In true_dependence we also allow BLKmode to alias anything. Why | |
2289 | don't we do this in anti_dependence and output_dependence? */ | |
2290 | if (mem_mode == BLKmode || GET_MODE (x) == BLKmode) | |
2291 | return 1; | |
2292 | ||
2293 | return ! fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, | |
2294 | varies); | |
2295 | } | |
2296 | ||
2297 | /* Canonical true dependence: X is read after store in MEM takes place. | |
ca7fd9cd KH |
2298 | Variant of true_dependence which assumes MEM has already been |
2299 | canonicalized (hence we no longer do that here). | |
2300 | The mem_addr argument has been added, since true_dependence computed | |
6216f94e JJ |
2301 | this value prior to canonicalizing. |
2302 | If x_addr is non-NULL, it is used in preference of XEXP (x, 0). */ | |
a13d4ebf AM |
2303 | |
2304 | int | |
4f588890 | 2305 | canon_true_dependence (const_rtx mem, enum machine_mode mem_mode, rtx mem_addr, |
6216f94e | 2306 | const_rtx x, rtx x_addr, bool (*varies) (const_rtx, bool)) |
a13d4ebf | 2307 | { |
a13d4ebf AM |
2308 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) |
2309 | return 1; | |
2310 | ||
0fe854a7 RH |
2311 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
2312 | This is used in epilogue deallocation functions. */ | |
2313 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) | |
2314 | return 1; | |
2315 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
2316 | return 1; | |
9cd9e512 RH |
2317 | if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER |
2318 | || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER) | |
2319 | return 1; | |
0fe854a7 | 2320 | |
a13d4ebf AM |
2321 | if (DIFFERENT_ALIAS_SETS_P (x, mem)) |
2322 | return 0; | |
2323 | ||
389fdba0 RH |
2324 | /* Read-only memory is by definition never modified, and therefore can't |
2325 | conflict with anything. We don't expect to find read-only set on MEM, | |
41806d92 | 2326 | but stupid user tricks can produce them, so don't die. */ |
389fdba0 | 2327 | if (MEM_READONLY_P (x)) |
a13d4ebf AM |
2328 | return 0; |
2329 | ||
a4311dfe RK |
2330 | if (nonoverlapping_memrefs_p (x, mem)) |
2331 | return 0; | |
2332 | ||
6216f94e JJ |
2333 | if (! x_addr) |
2334 | x_addr = get_addr (XEXP (x, 0)); | |
a13d4ebf AM |
2335 | |
2336 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), mem_mode)) | |
2337 | return 0; | |
2338 | ||
2339 | x_addr = canon_rtx (x_addr); | |
2340 | if (! memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr, | |
2341 | SIZE_FOR_MODE (x), x_addr, 0)) | |
2342 | return 0; | |
2343 | ||
2344 | if (aliases_everything_p (x)) | |
2345 | return 1; | |
2346 | ||
f5143c46 | 2347 | /* We cannot use aliases_everything_p to test MEM, since we must look |
a13d4ebf AM |
2348 | at MEM_MODE, rather than GET_MODE (MEM). */ |
2349 | if (mem_mode == QImode || GET_CODE (mem_addr) == AND) | |
c6df88cb | 2350 | return 1; |
0211b6ab | 2351 | |
c6df88cb MM |
2352 | /* In true_dependence we also allow BLKmode to alias anything. Why |
2353 | don't we do this in anti_dependence and output_dependence? */ | |
2354 | if (mem_mode == BLKmode || GET_MODE (x) == BLKmode) | |
2355 | return 1; | |
0211b6ab | 2356 | |
eab5c70a BS |
2357 | return ! fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, |
2358 | varies); | |
9ae8ffe7 JL |
2359 | } |
2360 | ||
da7d8304 | 2361 | /* Returns nonzero if a write to X might alias a previous read from |
389fdba0 | 2362 | (or, if WRITEP is nonzero, a write to) MEM. */ |
9ae8ffe7 | 2363 | |
2c72b78f | 2364 | static int |
4f588890 | 2365 | write_dependence_p (const_rtx mem, const_rtx x, int writep) |
9ae8ffe7 | 2366 | { |
6e73e666 | 2367 | rtx x_addr, mem_addr; |
4f588890 | 2368 | const_rtx fixed_scalar; |
49982682 | 2369 | rtx base; |
6e73e666 | 2370 | |
9ae8ffe7 JL |
2371 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) |
2372 | return 1; | |
2373 | ||
c4484b8f RH |
2374 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
2375 | This is used in epilogue deallocation functions. */ | |
2376 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) | |
2377 | return 1; | |
2378 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
2379 | return 1; | |
9cd9e512 RH |
2380 | if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER |
2381 | || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER) | |
2382 | return 1; | |
c4484b8f | 2383 | |
389fdba0 RH |
2384 | /* A read from read-only memory can't conflict with read-write memory. */ |
2385 | if (!writep && MEM_READONLY_P (mem)) | |
2386 | return 0; | |
55efb413 | 2387 | |
a4311dfe RK |
2388 | if (nonoverlapping_memrefs_p (x, mem)) |
2389 | return 0; | |
2390 | ||
55efb413 JW |
2391 | x_addr = get_addr (XEXP (x, 0)); |
2392 | mem_addr = get_addr (XEXP (mem, 0)); | |
2393 | ||
49982682 JW |
2394 | if (! writep) |
2395 | { | |
55efb413 | 2396 | base = find_base_term (mem_addr); |
49982682 JW |
2397 | if (base && (GET_CODE (base) == LABEL_REF |
2398 | || (GET_CODE (base) == SYMBOL_REF | |
2399 | && CONSTANT_POOL_ADDRESS_P (base)))) | |
2400 | return 0; | |
2401 | } | |
2402 | ||
eab5c70a BS |
2403 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), |
2404 | GET_MODE (mem))) | |
41472af8 MM |
2405 | return 0; |
2406 | ||
eab5c70a BS |
2407 | x_addr = canon_rtx (x_addr); |
2408 | mem_addr = canon_rtx (mem_addr); | |
6e73e666 | 2409 | |
c6df88cb MM |
2410 | if (!memrefs_conflict_p (SIZE_FOR_MODE (mem), mem_addr, |
2411 | SIZE_FOR_MODE (x), x_addr, 0)) | |
2412 | return 0; | |
2413 | ||
ca7fd9cd | 2414 | fixed_scalar |
eab5c70a BS |
2415 | = fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, |
2416 | rtx_addr_varies_p); | |
2417 | ||
c6df88cb MM |
2418 | return (!(fixed_scalar == mem && !aliases_everything_p (x)) |
2419 | && !(fixed_scalar == x && !aliases_everything_p (mem))); | |
2420 | } | |
2421 | ||
2422 | /* Anti dependence: X is written after read in MEM takes place. */ | |
2423 | ||
2424 | int | |
4f588890 | 2425 | anti_dependence (const_rtx mem, const_rtx x) |
c6df88cb | 2426 | { |
389fdba0 | 2427 | return write_dependence_p (mem, x, /*writep=*/0); |
9ae8ffe7 JL |
2428 | } |
2429 | ||
2430 | /* Output dependence: X is written after store in MEM takes place. */ | |
2431 | ||
2432 | int | |
4f588890 | 2433 | output_dependence (const_rtx mem, const_rtx x) |
9ae8ffe7 | 2434 | { |
389fdba0 | 2435 | return write_dependence_p (mem, x, /*writep=*/1); |
9ae8ffe7 | 2436 | } |
c14b9960 | 2437 | \f |
6e73e666 | 2438 | |
6e73e666 | 2439 | void |
b5deb7b6 | 2440 | init_alias_target (void) |
6e73e666 | 2441 | { |
b3694847 | 2442 | int i; |
6e73e666 | 2443 | |
b5deb7b6 SL |
2444 | memset (static_reg_base_value, 0, sizeof static_reg_base_value); |
2445 | ||
6e73e666 JC |
2446 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) |
2447 | /* Check whether this register can hold an incoming pointer | |
2448 | argument. FUNCTION_ARG_REGNO_P tests outgoing register | |
ec5c56db | 2449 | numbers, so translate if necessary due to register windows. */ |
6e73e666 JC |
2450 | if (FUNCTION_ARG_REGNO_P (OUTGOING_REGNO (i)) |
2451 | && HARD_REGNO_MODE_OK (i, Pmode)) | |
bf1660a6 JL |
2452 | static_reg_base_value[i] |
2453 | = gen_rtx_ADDRESS (VOIDmode, gen_rtx_REG (Pmode, i)); | |
2454 | ||
bf1660a6 JL |
2455 | static_reg_base_value[STACK_POINTER_REGNUM] |
2456 | = gen_rtx_ADDRESS (Pmode, stack_pointer_rtx); | |
2457 | static_reg_base_value[ARG_POINTER_REGNUM] | |
2458 | = gen_rtx_ADDRESS (Pmode, arg_pointer_rtx); | |
2459 | static_reg_base_value[FRAME_POINTER_REGNUM] | |
2460 | = gen_rtx_ADDRESS (Pmode, frame_pointer_rtx); | |
2461 | #if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM | |
2462 | static_reg_base_value[HARD_FRAME_POINTER_REGNUM] | |
2463 | = gen_rtx_ADDRESS (Pmode, hard_frame_pointer_rtx); | |
2464 | #endif | |
2465 | } | |
2466 | ||
7b52eede JH |
2467 | /* Set MEMORY_MODIFIED when X modifies DATA (that is assumed |
2468 | to be memory reference. */ | |
2469 | static bool memory_modified; | |
2470 | static void | |
aa317c97 | 2471 | memory_modified_1 (rtx x, const_rtx pat ATTRIBUTE_UNUSED, void *data) |
7b52eede | 2472 | { |
3c0cb5de | 2473 | if (MEM_P (x)) |
7b52eede | 2474 | { |
9678086d | 2475 | if (anti_dependence (x, (const_rtx)data) || output_dependence (x, (const_rtx)data)) |
7b52eede JH |
2476 | memory_modified = true; |
2477 | } | |
2478 | } | |
2479 | ||
2480 | ||
2481 | /* Return true when INSN possibly modify memory contents of MEM | |
454ff5cb | 2482 | (i.e. address can be modified). */ |
7b52eede | 2483 | bool |
9678086d | 2484 | memory_modified_in_insn_p (const_rtx mem, const_rtx insn) |
7b52eede JH |
2485 | { |
2486 | if (!INSN_P (insn)) | |
2487 | return false; | |
2488 | memory_modified = false; | |
aa317c97 | 2489 | note_stores (PATTERN (insn), memory_modified_1, CONST_CAST_RTX(mem)); |
7b52eede JH |
2490 | return memory_modified; |
2491 | } | |
2492 | ||
c13e8210 MM |
2493 | /* Initialize the aliasing machinery. Initialize the REG_KNOWN_VALUE |
2494 | array. */ | |
2495 | ||
9ae8ffe7 | 2496 | void |
4682ae04 | 2497 | init_alias_analysis (void) |
9ae8ffe7 | 2498 | { |
c582d54a | 2499 | unsigned int maxreg = max_reg_num (); |
ea64ef27 | 2500 | int changed, pass; |
b3694847 SS |
2501 | int i; |
2502 | unsigned int ui; | |
2503 | rtx insn; | |
9ae8ffe7 | 2504 | |
0d446150 JH |
2505 | timevar_push (TV_ALIAS_ANALYSIS); |
2506 | ||
bb1acb3e | 2507 | reg_known_value_size = maxreg - FIRST_PSEUDO_REGISTER; |
f883e0a7 KG |
2508 | reg_known_value = GGC_CNEWVEC (rtx, reg_known_value_size); |
2509 | reg_known_equiv_p = XCNEWVEC (bool, reg_known_value_size); | |
9ae8ffe7 | 2510 | |
08c79682 | 2511 | /* If we have memory allocated from the previous run, use it. */ |
c582d54a | 2512 | if (old_reg_base_value) |
08c79682 KH |
2513 | reg_base_value = old_reg_base_value; |
2514 | ||
2515 | if (reg_base_value) | |
2516 | VEC_truncate (rtx, reg_base_value, 0); | |
2517 | ||
a590ac65 | 2518 | VEC_safe_grow_cleared (rtx, gc, reg_base_value, maxreg); |
ac606739 | 2519 | |
5ed6ace5 MD |
2520 | new_reg_base_value = XNEWVEC (rtx, maxreg); |
2521 | reg_seen = XNEWVEC (char, maxreg); | |
ec907dd8 JL |
2522 | |
2523 | /* The basic idea is that each pass through this loop will use the | |
2524 | "constant" information from the previous pass to propagate alias | |
2525 | information through another level of assignments. | |
2526 | ||
2527 | This could get expensive if the assignment chains are long. Maybe | |
2528 | we should throttle the number of iterations, possibly based on | |
6e73e666 | 2529 | the optimization level or flag_expensive_optimizations. |
ec907dd8 JL |
2530 | |
2531 | We could propagate more information in the first pass by making use | |
6fb5fa3c | 2532 | of DF_REG_DEF_COUNT to determine immediately that the alias information |
ea64ef27 JL |
2533 | for a pseudo is "constant". |
2534 | ||
2535 | A program with an uninitialized variable can cause an infinite loop | |
2536 | here. Instead of doing a full dataflow analysis to detect such problems | |
2537 | we just cap the number of iterations for the loop. | |
2538 | ||
2539 | The state of the arrays for the set chain in question does not matter | |
2540 | since the program has undefined behavior. */ | |
6e73e666 | 2541 | |
ea64ef27 | 2542 | pass = 0; |
6e73e666 | 2543 | do |
ec907dd8 JL |
2544 | { |
2545 | /* Assume nothing will change this iteration of the loop. */ | |
2546 | changed = 0; | |
2547 | ||
ec907dd8 JL |
2548 | /* We want to assign the same IDs each iteration of this loop, so |
2549 | start counting from zero each iteration of the loop. */ | |
2550 | unique_id = 0; | |
2551 | ||
f5143c46 | 2552 | /* We're at the start of the function each iteration through the |
ec907dd8 | 2553 | loop, so we're copying arguments. */ |
83bbd9b6 | 2554 | copying_arguments = true; |
9ae8ffe7 | 2555 | |
6e73e666 | 2556 | /* Wipe the potential alias information clean for this pass. */ |
c582d54a | 2557 | memset (new_reg_base_value, 0, maxreg * sizeof (rtx)); |
8072f69c | 2558 | |
6e73e666 | 2559 | /* Wipe the reg_seen array clean. */ |
c582d54a | 2560 | memset (reg_seen, 0, maxreg); |
9ae8ffe7 | 2561 | |
6e73e666 JC |
2562 | /* Mark all hard registers which may contain an address. |
2563 | The stack, frame and argument pointers may contain an address. | |
2564 | An argument register which can hold a Pmode value may contain | |
2565 | an address even if it is not in BASE_REGS. | |
8072f69c | 2566 | |
6e73e666 JC |
2567 | The address expression is VOIDmode for an argument and |
2568 | Pmode for other registers. */ | |
2569 | ||
7f243674 JL |
2570 | memcpy (new_reg_base_value, static_reg_base_value, |
2571 | FIRST_PSEUDO_REGISTER * sizeof (rtx)); | |
6e73e666 | 2572 | |
ec907dd8 JL |
2573 | /* Walk the insns adding values to the new_reg_base_value array. */ |
2574 | for (insn = get_insns (); insn; insn = NEXT_INSN (insn)) | |
9ae8ffe7 | 2575 | { |
2c3c49de | 2576 | if (INSN_P (insn)) |
ec907dd8 | 2577 | { |
6e73e666 | 2578 | rtx note, set; |
efc9bd41 RK |
2579 | |
2580 | #if defined (HAVE_prologue) || defined (HAVE_epilogue) | |
f5143c46 | 2581 | /* The prologue/epilogue insns are not threaded onto the |
657959ca JL |
2582 | insn chain until after reload has completed. Thus, |
2583 | there is no sense wasting time checking if INSN is in | |
2584 | the prologue/epilogue until after reload has completed. */ | |
2585 | if (reload_completed | |
2586 | && prologue_epilogue_contains (insn)) | |
efc9bd41 RK |
2587 | continue; |
2588 | #endif | |
2589 | ||
ec907dd8 | 2590 | /* If this insn has a noalias note, process it, Otherwise, |
c22cacf3 MS |
2591 | scan for sets. A simple set will have no side effects |
2592 | which could change the base value of any other register. */ | |
6e73e666 | 2593 | |
ec907dd8 | 2594 | if (GET_CODE (PATTERN (insn)) == SET |
efc9bd41 RK |
2595 | && REG_NOTES (insn) != 0 |
2596 | && find_reg_note (insn, REG_NOALIAS, NULL_RTX)) | |
84832317 | 2597 | record_set (SET_DEST (PATTERN (insn)), NULL_RTX, NULL); |
ec907dd8 | 2598 | else |
84832317 | 2599 | note_stores (PATTERN (insn), record_set, NULL); |
6e73e666 JC |
2600 | |
2601 | set = single_set (insn); | |
2602 | ||
2603 | if (set != 0 | |
f8cfc6aa | 2604 | && REG_P (SET_DEST (set)) |
fb6754f0 | 2605 | && REGNO (SET_DEST (set)) >= FIRST_PSEUDO_REGISTER) |
6e73e666 | 2606 | { |
fb6754f0 | 2607 | unsigned int regno = REGNO (SET_DEST (set)); |
713f41f9 | 2608 | rtx src = SET_SRC (set); |
bb1acb3e | 2609 | rtx t; |
713f41f9 | 2610 | |
a31830a7 SB |
2611 | note = find_reg_equal_equiv_note (insn); |
2612 | if (note && REG_NOTE_KIND (note) == REG_EQUAL | |
6fb5fa3c | 2613 | && DF_REG_DEF_COUNT (regno) != 1) |
a31830a7 SB |
2614 | note = NULL_RTX; |
2615 | ||
2616 | if (note != NULL_RTX | |
713f41f9 | 2617 | && GET_CODE (XEXP (note, 0)) != EXPR_LIST |
bb2cf916 | 2618 | && ! rtx_varies_p (XEXP (note, 0), 1) |
bb1acb3e RH |
2619 | && ! reg_overlap_mentioned_p (SET_DEST (set), |
2620 | XEXP (note, 0))) | |
713f41f9 | 2621 | { |
bb1acb3e RH |
2622 | set_reg_known_value (regno, XEXP (note, 0)); |
2623 | set_reg_known_equiv_p (regno, | |
2624 | REG_NOTE_KIND (note) == REG_EQUIV); | |
713f41f9 | 2625 | } |
6fb5fa3c | 2626 | else if (DF_REG_DEF_COUNT (regno) == 1 |
713f41f9 | 2627 | && GET_CODE (src) == PLUS |
f8cfc6aa | 2628 | && REG_P (XEXP (src, 0)) |
bb1acb3e | 2629 | && (t = get_reg_known_value (REGNO (XEXP (src, 0)))) |
481683e1 | 2630 | && CONST_INT_P (XEXP (src, 1))) |
713f41f9 | 2631 | { |
bb1acb3e RH |
2632 | t = plus_constant (t, INTVAL (XEXP (src, 1))); |
2633 | set_reg_known_value (regno, t); | |
2634 | set_reg_known_equiv_p (regno, 0); | |
713f41f9 | 2635 | } |
6fb5fa3c | 2636 | else if (DF_REG_DEF_COUNT (regno) == 1 |
713f41f9 BS |
2637 | && ! rtx_varies_p (src, 1)) |
2638 | { | |
bb1acb3e RH |
2639 | set_reg_known_value (regno, src); |
2640 | set_reg_known_equiv_p (regno, 0); | |
713f41f9 | 2641 | } |
6e73e666 | 2642 | } |
ec907dd8 | 2643 | } |
4b4bf941 | 2644 | else if (NOTE_P (insn) |
a38e7aa5 | 2645 | && NOTE_KIND (insn) == NOTE_INSN_FUNCTION_BEG) |
83bbd9b6 | 2646 | copying_arguments = false; |
6e73e666 | 2647 | } |
ec907dd8 | 2648 | |
6e73e666 | 2649 | /* Now propagate values from new_reg_base_value to reg_base_value. */ |
62e5bf5d | 2650 | gcc_assert (maxreg == (unsigned int) max_reg_num ()); |
c22cacf3 | 2651 | |
c582d54a | 2652 | for (ui = 0; ui < maxreg; ui++) |
6e73e666 | 2653 | { |
e51712db | 2654 | if (new_reg_base_value[ui] |
08c79682 | 2655 | && new_reg_base_value[ui] != VEC_index (rtx, reg_base_value, ui) |
c582d54a | 2656 | && ! rtx_equal_p (new_reg_base_value[ui], |
08c79682 | 2657 | VEC_index (rtx, reg_base_value, ui))) |
ec907dd8 | 2658 | { |
08c79682 | 2659 | VEC_replace (rtx, reg_base_value, ui, new_reg_base_value[ui]); |
6e73e666 | 2660 | changed = 1; |
ec907dd8 | 2661 | } |
9ae8ffe7 | 2662 | } |
9ae8ffe7 | 2663 | } |
6e73e666 | 2664 | while (changed && ++pass < MAX_ALIAS_LOOP_PASSES); |
9ae8ffe7 JL |
2665 | |
2666 | /* Fill in the remaining entries. */ | |
bb1acb3e | 2667 | for (i = 0; i < (int)reg_known_value_size; i++) |
9ae8ffe7 | 2668 | if (reg_known_value[i] == 0) |
bb1acb3e | 2669 | reg_known_value[i] = regno_reg_rtx[i + FIRST_PSEUDO_REGISTER]; |
9ae8ffe7 | 2670 | |
e05e2395 MM |
2671 | /* Clean up. */ |
2672 | free (new_reg_base_value); | |
ec907dd8 | 2673 | new_reg_base_value = 0; |
e05e2395 | 2674 | free (reg_seen); |
9ae8ffe7 | 2675 | reg_seen = 0; |
0d446150 | 2676 | timevar_pop (TV_ALIAS_ANALYSIS); |
9ae8ffe7 JL |
2677 | } |
2678 | ||
2679 | void | |
4682ae04 | 2680 | end_alias_analysis (void) |
9ae8ffe7 | 2681 | { |
c582d54a | 2682 | old_reg_base_value = reg_base_value; |
bb1acb3e | 2683 | ggc_free (reg_known_value); |
9ae8ffe7 | 2684 | reg_known_value = 0; |
ac606739 | 2685 | reg_known_value_size = 0; |
bb1acb3e | 2686 | free (reg_known_equiv_p); |
e05e2395 | 2687 | reg_known_equiv_p = 0; |
9ae8ffe7 | 2688 | } |
e2500fed GK |
2689 | |
2690 | #include "gt-alias.h" |