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9ae8ffe7 | 1 | /* Alias analysis for GNU C |
62e5bf5d RS |
2 | Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, |
3 | 2007 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 | ||
b604074c | 131 | struct alias_set_entry GTY(()) |
d4b60170 | 132 | { |
3932261a | 133 | /* The alias set number, as stored in MEM_ALIAS_SET. */ |
4862826d | 134 | alias_set_type alias_set; |
3932261a | 135 | |
4c067742 RG |
136 | /* Nonzero if would have a child of zero: this effectively makes this |
137 | alias set the same as alias set zero. */ | |
138 | int has_zero_child; | |
139 | ||
3932261a | 140 | /* The children of the alias set. These are not just the immediate |
95bd1dd7 | 141 | children, but, in fact, all descendants. So, if we have: |
3932261a | 142 | |
ca7fd9cd | 143 | struct T { struct S s; float f; } |
3932261a MM |
144 | |
145 | continuing our example above, the children here will be all of | |
146 | `int', `double', `float', and `struct S'. */ | |
b604074c | 147 | splay_tree GTY((param1_is (int), param2_is (int))) children; |
b604074c GK |
148 | }; |
149 | typedef struct alias_set_entry *alias_set_entry; | |
9ae8ffe7 | 150 | |
ed7a4b4b | 151 | static int rtx_equal_for_memref_p (const_rtx, const_rtx); |
4682ae04 | 152 | static int memrefs_conflict_p (int, rtx, int, rtx, HOST_WIDE_INT); |
7bc980e1 | 153 | static void record_set (rtx, const_rtx, void *); |
4682ae04 AJ |
154 | static int base_alias_check (rtx, rtx, enum machine_mode, |
155 | enum machine_mode); | |
156 | static rtx find_base_value (rtx); | |
4f588890 | 157 | static int mems_in_disjoint_alias_sets_p (const_rtx, const_rtx); |
4682ae04 AJ |
158 | static int insert_subset_children (splay_tree_node, void*); |
159 | static tree find_base_decl (tree); | |
4862826d | 160 | static alias_set_entry get_alias_set_entry (alias_set_type); |
4f588890 KG |
161 | static const_rtx fixed_scalar_and_varying_struct_p (const_rtx, const_rtx, rtx, rtx, |
162 | bool (*) (const_rtx, bool)); | |
163 | static int aliases_everything_p (const_rtx); | |
164 | static bool nonoverlapping_component_refs_p (const_tree, const_tree); | |
4682ae04 AJ |
165 | static tree decl_for_component_ref (tree); |
166 | static rtx adjust_offset_for_component_ref (tree, rtx); | |
4f588890 | 167 | static int write_dependence_p (const_rtx, const_rtx, int); |
4682ae04 | 168 | |
aa317c97 | 169 | static void memory_modified_1 (rtx, const_rtx, void *); |
4862826d | 170 | static void record_alias_subset (alias_set_type, alias_set_type); |
9ae8ffe7 JL |
171 | |
172 | /* Set up all info needed to perform alias analysis on memory references. */ | |
173 | ||
d4b60170 | 174 | /* Returns the size in bytes of the mode of X. */ |
9ae8ffe7 JL |
175 | #define SIZE_FOR_MODE(X) (GET_MODE_SIZE (GET_MODE (X))) |
176 | ||
41472af8 | 177 | /* Returns nonzero if MEM1 and MEM2 do not alias because they are in |
264fac34 MM |
178 | different alias sets. We ignore alias sets in functions making use |
179 | of variable arguments because the va_arg macros on some systems are | |
180 | not legal ANSI C. */ | |
181 | #define DIFFERENT_ALIAS_SETS_P(MEM1, MEM2) \ | |
3932261a | 182 | mems_in_disjoint_alias_sets_p (MEM1, MEM2) |
41472af8 | 183 | |
ea64ef27 | 184 | /* Cap the number of passes we make over the insns propagating alias |
ac3d9668 | 185 | information through set chains. 10 is a completely arbitrary choice. */ |
ea64ef27 | 186 | #define MAX_ALIAS_LOOP_PASSES 10 |
ca7fd9cd | 187 | |
9ae8ffe7 JL |
188 | /* reg_base_value[N] gives an address to which register N is related. |
189 | If all sets after the first add or subtract to the current value | |
190 | or otherwise modify it so it does not point to a different top level | |
191 | object, reg_base_value[N] is equal to the address part of the source | |
2a2c8203 JC |
192 | of the first set. |
193 | ||
194 | A base address can be an ADDRESS, SYMBOL_REF, or LABEL_REF. ADDRESS | |
195 | expressions represent certain special values: function arguments and | |
ca7fd9cd | 196 | the stack, frame, and argument pointers. |
b3b5ad95 JL |
197 | |
198 | The contents of an ADDRESS is not normally used, the mode of the | |
199 | ADDRESS determines whether the ADDRESS is a function argument or some | |
200 | other special value. Pointer equality, not rtx_equal_p, determines whether | |
201 | two ADDRESS expressions refer to the same base address. | |
202 | ||
203 | The only use of the contents of an ADDRESS is for determining if the | |
204 | current function performs nonlocal memory memory references for the | |
205 | purposes of marking the function as a constant function. */ | |
2a2c8203 | 206 | |
08c79682 | 207 | static GTY(()) VEC(rtx,gc) *reg_base_value; |
ac606739 | 208 | static rtx *new_reg_base_value; |
c582d54a JH |
209 | |
210 | /* We preserve the copy of old array around to avoid amount of garbage | |
211 | produced. About 8% of garbage produced were attributed to this | |
212 | array. */ | |
08c79682 | 213 | static GTY((deletable)) VEC(rtx,gc) *old_reg_base_value; |
d4b60170 | 214 | |
bf1660a6 JL |
215 | /* Static hunks of RTL used by the aliasing code; these are initialized |
216 | once per function to avoid unnecessary RTL allocations. */ | |
217 | static GTY (()) rtx static_reg_base_value[FIRST_PSEUDO_REGISTER]; | |
218 | ||
08c79682 KH |
219 | #define REG_BASE_VALUE(X) \ |
220 | (REGNO (X) < VEC_length (rtx, reg_base_value) \ | |
221 | ? VEC_index (rtx, reg_base_value, REGNO (X)) : 0) | |
9ae8ffe7 | 222 | |
c13e8210 | 223 | /* Vector indexed by N giving the initial (unchanging) value known for |
bb1acb3e RH |
224 | pseudo-register N. This array is initialized in init_alias_analysis, |
225 | and does not change until end_alias_analysis is called. */ | |
226 | static GTY((length("reg_known_value_size"))) rtx *reg_known_value; | |
9ae8ffe7 JL |
227 | |
228 | /* Indicates number of valid entries in reg_known_value. */ | |
bb1acb3e | 229 | static GTY(()) unsigned int reg_known_value_size; |
9ae8ffe7 JL |
230 | |
231 | /* Vector recording for each reg_known_value whether it is due to a | |
232 | REG_EQUIV note. Future passes (viz., reload) may replace the | |
233 | pseudo with the equivalent expression and so we account for the | |
ac3d9668 RK |
234 | dependences that would be introduced if that happens. |
235 | ||
236 | The REG_EQUIV notes created in assign_parms may mention the arg | |
237 | pointer, and there are explicit insns in the RTL that modify the | |
238 | arg pointer. Thus we must ensure that such insns don't get | |
239 | scheduled across each other because that would invalidate the | |
240 | REG_EQUIV notes. One could argue that the REG_EQUIV notes are | |
241 | wrong, but solving the problem in the scheduler will likely give | |
242 | better code, so we do it here. */ | |
bb1acb3e | 243 | static bool *reg_known_equiv_p; |
9ae8ffe7 | 244 | |
2a2c8203 JC |
245 | /* True when scanning insns from the start of the rtl to the |
246 | NOTE_INSN_FUNCTION_BEG note. */ | |
83bbd9b6 | 247 | static bool copying_arguments; |
9ae8ffe7 | 248 | |
1a5640b4 KH |
249 | DEF_VEC_P(alias_set_entry); |
250 | DEF_VEC_ALLOC_P(alias_set_entry,gc); | |
251 | ||
3932261a | 252 | /* The splay-tree used to store the various alias set entries. */ |
1a5640b4 | 253 | static GTY (()) VEC(alias_set_entry,gc) *alias_sets; |
ac3d9668 | 254 | \f |
3932261a MM |
255 | /* Returns a pointer to the alias set entry for ALIAS_SET, if there is |
256 | such an entry, or NULL otherwise. */ | |
257 | ||
9ddb66ca | 258 | static inline alias_set_entry |
4862826d | 259 | get_alias_set_entry (alias_set_type alias_set) |
3932261a | 260 | { |
1a5640b4 | 261 | return VEC_index (alias_set_entry, alias_sets, alias_set); |
3932261a MM |
262 | } |
263 | ||
ac3d9668 RK |
264 | /* Returns nonzero if the alias sets for MEM1 and MEM2 are such that |
265 | the two MEMs cannot alias each other. */ | |
3932261a | 266 | |
9ddb66ca | 267 | static inline int |
4f588890 | 268 | mems_in_disjoint_alias_sets_p (const_rtx mem1, const_rtx mem2) |
3932261a | 269 | { |
3932261a MM |
270 | /* Perform a basic sanity check. Namely, that there are no alias sets |
271 | if we're not using strict aliasing. This helps to catch bugs | |
272 | whereby someone uses PUT_CODE, but doesn't clear MEM_ALIAS_SET, or | |
273 | where a MEM is allocated in some way other than by the use of | |
274 | gen_rtx_MEM, and the MEM_ALIAS_SET is not cleared. If we begin to | |
275 | use alias sets to indicate that spilled registers cannot alias each | |
276 | other, we might need to remove this check. */ | |
298e6adc NS |
277 | gcc_assert (flag_strict_aliasing |
278 | || (!MEM_ALIAS_SET (mem1) && !MEM_ALIAS_SET (mem2))); | |
3932261a | 279 | |
1da68f56 RK |
280 | return ! alias_sets_conflict_p (MEM_ALIAS_SET (mem1), MEM_ALIAS_SET (mem2)); |
281 | } | |
3932261a | 282 | |
1da68f56 RK |
283 | /* Insert the NODE into the splay tree given by DATA. Used by |
284 | record_alias_subset via splay_tree_foreach. */ | |
285 | ||
286 | static int | |
4682ae04 | 287 | insert_subset_children (splay_tree_node node, void *data) |
1da68f56 RK |
288 | { |
289 | splay_tree_insert ((splay_tree) data, node->key, node->value); | |
290 | ||
291 | return 0; | |
292 | } | |
293 | ||
c58936b6 DB |
294 | /* Return true if the first alias set is a subset of the second. */ |
295 | ||
296 | bool | |
4862826d | 297 | alias_set_subset_of (alias_set_type set1, alias_set_type set2) |
c58936b6 DB |
298 | { |
299 | alias_set_entry ase; | |
300 | ||
301 | /* Everything is a subset of the "aliases everything" set. */ | |
302 | if (set2 == 0) | |
303 | return true; | |
304 | ||
305 | /* Otherwise, check if set1 is a subset of set2. */ | |
306 | ase = get_alias_set_entry (set2); | |
307 | if (ase != 0 | |
a7a512be RG |
308 | && ((ase->has_zero_child && set1 == 0) |
309 | || splay_tree_lookup (ase->children, | |
310 | (splay_tree_key) set1))) | |
c58936b6 DB |
311 | return true; |
312 | return false; | |
313 | } | |
314 | ||
1da68f56 RK |
315 | /* Return 1 if the two specified alias sets may conflict. */ |
316 | ||
317 | int | |
4862826d | 318 | alias_sets_conflict_p (alias_set_type set1, alias_set_type set2) |
1da68f56 RK |
319 | { |
320 | alias_set_entry ase; | |
321 | ||
836f7794 EB |
322 | /* The easy case. */ |
323 | if (alias_sets_must_conflict_p (set1, set2)) | |
1da68f56 | 324 | return 1; |
3932261a | 325 | |
3bdf5ad1 | 326 | /* See if the first alias set is a subset of the second. */ |
1da68f56 | 327 | ase = get_alias_set_entry (set1); |
2bf105ab RK |
328 | if (ase != 0 |
329 | && (ase->has_zero_child | |
330 | || splay_tree_lookup (ase->children, | |
1da68f56 RK |
331 | (splay_tree_key) set2))) |
332 | return 1; | |
3932261a MM |
333 | |
334 | /* Now do the same, but with the alias sets reversed. */ | |
1da68f56 | 335 | ase = get_alias_set_entry (set2); |
2bf105ab RK |
336 | if (ase != 0 |
337 | && (ase->has_zero_child | |
338 | || splay_tree_lookup (ase->children, | |
1da68f56 RK |
339 | (splay_tree_key) set1))) |
340 | return 1; | |
3932261a | 341 | |
1da68f56 | 342 | /* The two alias sets are distinct and neither one is the |
836f7794 | 343 | child of the other. Therefore, they cannot conflict. */ |
1da68f56 | 344 | return 0; |
3932261a | 345 | } |
5399d643 | 346 | |
836f7794 | 347 | /* Return 1 if the two specified alias sets will always conflict. */ |
5399d643 JW |
348 | |
349 | int | |
4862826d | 350 | alias_sets_must_conflict_p (alias_set_type set1, alias_set_type set2) |
5399d643 JW |
351 | { |
352 | if (set1 == 0 || set2 == 0 || set1 == set2) | |
353 | return 1; | |
354 | ||
355 | return 0; | |
356 | } | |
357 | ||
1da68f56 RK |
358 | /* Return 1 if any MEM object of type T1 will always conflict (using the |
359 | dependency routines in this file) with any MEM object of type T2. | |
360 | This is used when allocating temporary storage. If T1 and/or T2 are | |
361 | NULL_TREE, it means we know nothing about the storage. */ | |
362 | ||
363 | int | |
4682ae04 | 364 | objects_must_conflict_p (tree t1, tree t2) |
1da68f56 | 365 | { |
4862826d | 366 | alias_set_type set1, set2; |
82d610ec | 367 | |
e8ea2809 RK |
368 | /* If neither has a type specified, we don't know if they'll conflict |
369 | because we may be using them to store objects of various types, for | |
370 | example the argument and local variables areas of inlined functions. */ | |
981a4c34 | 371 | if (t1 == 0 && t2 == 0) |
e8ea2809 RK |
372 | return 0; |
373 | ||
1da68f56 RK |
374 | /* If they are the same type, they must conflict. */ |
375 | if (t1 == t2 | |
376 | /* Likewise if both are volatile. */ | |
377 | || (t1 != 0 && TYPE_VOLATILE (t1) && t2 != 0 && TYPE_VOLATILE (t2))) | |
378 | return 1; | |
379 | ||
82d610ec RK |
380 | set1 = t1 ? get_alias_set (t1) : 0; |
381 | set2 = t2 ? get_alias_set (t2) : 0; | |
1da68f56 | 382 | |
836f7794 EB |
383 | /* We can't use alias_sets_conflict_p because we must make sure |
384 | that every subtype of t1 will conflict with every subtype of | |
82d610ec RK |
385 | t2 for which a pair of subobjects of these respective subtypes |
386 | overlaps on the stack. */ | |
836f7794 | 387 | return alias_sets_must_conflict_p (set1, set2); |
1da68f56 RK |
388 | } |
389 | \f | |
3bdf5ad1 RK |
390 | /* T is an expression with pointer type. Find the DECL on which this |
391 | expression is based. (For example, in `a[i]' this would be `a'.) | |
392 | If there is no such DECL, or a unique decl cannot be determined, | |
f5143c46 | 393 | NULL_TREE is returned. */ |
3bdf5ad1 RK |
394 | |
395 | static tree | |
4682ae04 | 396 | find_base_decl (tree t) |
3bdf5ad1 | 397 | { |
6615c446 | 398 | tree d0, d1; |
3bdf5ad1 RK |
399 | |
400 | if (t == 0 || t == error_mark_node || ! POINTER_TYPE_P (TREE_TYPE (t))) | |
401 | return 0; | |
402 | ||
0b494699 ILT |
403 | /* If this is a declaration, return it. If T is based on a restrict |
404 | qualified decl, return that decl. */ | |
6615c446 | 405 | if (DECL_P (t)) |
0b494699 ILT |
406 | { |
407 | if (TREE_CODE (t) == VAR_DECL && DECL_BASED_ON_RESTRICT_P (t)) | |
408 | t = DECL_GET_RESTRICT_BASE (t); | |
409 | return t; | |
410 | } | |
3bdf5ad1 RK |
411 | |
412 | /* Handle general expressions. It would be nice to deal with | |
413 | COMPONENT_REFs here. If we could tell that `a' and `b' were the | |
414 | same, then `a->f' and `b->f' are also the same. */ | |
415 | switch (TREE_CODE_CLASS (TREE_CODE (t))) | |
416 | { | |
6615c446 | 417 | case tcc_unary: |
3bdf5ad1 RK |
418 | return find_base_decl (TREE_OPERAND (t, 0)); |
419 | ||
6615c446 | 420 | case tcc_binary: |
3bdf5ad1 RK |
421 | /* Return 0 if found in neither or both are the same. */ |
422 | d0 = find_base_decl (TREE_OPERAND (t, 0)); | |
423 | d1 = find_base_decl (TREE_OPERAND (t, 1)); | |
424 | if (d0 == d1) | |
425 | return d0; | |
426 | else if (d0 == 0) | |
427 | return d1; | |
428 | else if (d1 == 0) | |
429 | return d0; | |
430 | else | |
431 | return 0; | |
432 | ||
3bdf5ad1 RK |
433 | default: |
434 | return 0; | |
435 | } | |
436 | } | |
437 | ||
2039d7aa RH |
438 | /* Return true if all nested component references handled by |
439 | get_inner_reference in T are such that we should use the alias set | |
440 | provided by the object at the heart of T. | |
441 | ||
442 | This is true for non-addressable components (which don't have their | |
443 | own alias set), as well as components of objects in alias set zero. | |
444 | This later point is a special case wherein we wish to override the | |
445 | alias set used by the component, but we don't have per-FIELD_DECL | |
446 | assignable alias sets. */ | |
447 | ||
448 | bool | |
22ea9ec0 | 449 | component_uses_parent_alias_set (const_tree t) |
6e24b709 | 450 | { |
afe84921 RH |
451 | while (1) |
452 | { | |
2039d7aa | 453 | /* If we're at the end, it vacuously uses its own alias set. */ |
afe84921 | 454 | if (!handled_component_p (t)) |
2039d7aa | 455 | return false; |
afe84921 RH |
456 | |
457 | switch (TREE_CODE (t)) | |
458 | { | |
459 | case COMPONENT_REF: | |
460 | if (DECL_NONADDRESSABLE_P (TREE_OPERAND (t, 1))) | |
2039d7aa | 461 | return true; |
afe84921 RH |
462 | break; |
463 | ||
464 | case ARRAY_REF: | |
465 | case ARRAY_RANGE_REF: | |
466 | if (TYPE_NONALIASED_COMPONENT (TREE_TYPE (TREE_OPERAND (t, 0)))) | |
2039d7aa | 467 | return true; |
afe84921 RH |
468 | break; |
469 | ||
470 | case REALPART_EXPR: | |
471 | case IMAGPART_EXPR: | |
472 | break; | |
473 | ||
474 | default: | |
475 | /* Bitfields and casts are never addressable. */ | |
2039d7aa | 476 | return true; |
afe84921 RH |
477 | } |
478 | ||
479 | t = TREE_OPERAND (t, 0); | |
2039d7aa RH |
480 | if (get_alias_set (TREE_TYPE (t)) == 0) |
481 | return true; | |
afe84921 | 482 | } |
6e24b709 RK |
483 | } |
484 | ||
3bdf5ad1 RK |
485 | /* Return the alias set for T, which may be either a type or an |
486 | expression. Call language-specific routine for help, if needed. */ | |
487 | ||
4862826d | 488 | alias_set_type |
4682ae04 | 489 | get_alias_set (tree t) |
3bdf5ad1 | 490 | { |
4862826d | 491 | alias_set_type set; |
3bdf5ad1 RK |
492 | |
493 | /* If we're not doing any alias analysis, just assume everything | |
494 | aliases everything else. Also return 0 if this or its type is | |
495 | an error. */ | |
496 | if (! flag_strict_aliasing || t == error_mark_node | |
497 | || (! TYPE_P (t) | |
498 | && (TREE_TYPE (t) == 0 || TREE_TYPE (t) == error_mark_node))) | |
499 | return 0; | |
500 | ||
501 | /* We can be passed either an expression or a type. This and the | |
f47e9b4e RK |
502 | language-specific routine may make mutually-recursive calls to each other |
503 | to figure out what to do. At each juncture, we see if this is a tree | |
504 | that the language may need to handle specially. First handle things that | |
738cc472 | 505 | aren't types. */ |
f824e5c3 | 506 | if (! TYPE_P (t)) |
3bdf5ad1 | 507 | { |
738cc472 | 508 | tree inner = t; |
738cc472 | 509 | |
8ac61af7 RK |
510 | /* Remove any nops, then give the language a chance to do |
511 | something with this tree before we look at it. */ | |
512 | STRIP_NOPS (t); | |
ae2bcd98 | 513 | set = lang_hooks.get_alias_set (t); |
8ac61af7 RK |
514 | if (set != -1) |
515 | return set; | |
516 | ||
738cc472 | 517 | /* First see if the actual object referenced is an INDIRECT_REF from a |
6fce44af RK |
518 | restrict-qualified pointer or a "void *". */ |
519 | while (handled_component_p (inner)) | |
738cc472 | 520 | { |
6fce44af | 521 | inner = TREE_OPERAND (inner, 0); |
8ac61af7 | 522 | STRIP_NOPS (inner); |
738cc472 RK |
523 | } |
524 | ||
525 | /* Check for accesses through restrict-qualified pointers. */ | |
1b096a0a | 526 | if (INDIRECT_REF_P (inner)) |
738cc472 | 527 | { |
90310d36 RG |
528 | tree decl; |
529 | ||
530 | if (TREE_CODE (TREE_OPERAND (inner, 0)) == SSA_NAME) | |
531 | decl = SSA_NAME_VAR (TREE_OPERAND (inner, 0)); | |
532 | else | |
533 | decl = find_base_decl (TREE_OPERAND (inner, 0)); | |
738cc472 RK |
534 | |
535 | if (decl && DECL_POINTER_ALIAS_SET_KNOWN_P (decl)) | |
536 | { | |
e5837c07 | 537 | /* If we haven't computed the actual alias set, do it now. */ |
738cc472 RK |
538 | if (DECL_POINTER_ALIAS_SET (decl) == -2) |
539 | { | |
4f430fb9 MM |
540 | tree pointed_to_type = TREE_TYPE (TREE_TYPE (decl)); |
541 | ||
738cc472 RK |
542 | /* No two restricted pointers can point at the same thing. |
543 | However, a restricted pointer can point at the same thing | |
544 | as an unrestricted pointer, if that unrestricted pointer | |
545 | is based on the restricted pointer. So, we make the | |
546 | alias set for the restricted pointer a subset of the | |
547 | alias set for the type pointed to by the type of the | |
548 | decl. */ | |
4862826d | 549 | alias_set_type pointed_to_alias_set |
4f430fb9 | 550 | = get_alias_set (pointed_to_type); |
738cc472 RK |
551 | |
552 | if (pointed_to_alias_set == 0) | |
553 | /* It's not legal to make a subset of alias set zero. */ | |
e7844ffb | 554 | DECL_POINTER_ALIAS_SET (decl) = 0; |
4f430fb9 MM |
555 | else if (AGGREGATE_TYPE_P (pointed_to_type)) |
556 | /* For an aggregate, we must treat the restricted | |
557 | pointer the same as an ordinary pointer. If we | |
558 | were to make the type pointed to by the | |
559 | restricted pointer a subset of the pointed-to | |
560 | type, then we would believe that other subsets | |
561 | of the pointed-to type (such as fields of that | |
562 | type) do not conflict with the type pointed to | |
471854f8 | 563 | by the restricted pointer. */ |
4f430fb9 MM |
564 | DECL_POINTER_ALIAS_SET (decl) |
565 | = pointed_to_alias_set; | |
738cc472 RK |
566 | else |
567 | { | |
568 | DECL_POINTER_ALIAS_SET (decl) = new_alias_set (); | |
ca7fd9cd KH |
569 | record_alias_subset (pointed_to_alias_set, |
570 | DECL_POINTER_ALIAS_SET (decl)); | |
738cc472 RK |
571 | } |
572 | } | |
573 | ||
574 | /* We use the alias set indicated in the declaration. */ | |
575 | return DECL_POINTER_ALIAS_SET (decl); | |
576 | } | |
577 | ||
578 | /* If we have an INDIRECT_REF via a void pointer, we don't | |
22421b79 RK |
579 | know anything about what that might alias. Likewise if the |
580 | pointer is marked that way. */ | |
581 | else if (TREE_CODE (TREE_TYPE (inner)) == VOID_TYPE | |
582 | || (TYPE_REF_CAN_ALIAS_ALL | |
583 | (TREE_TYPE (TREE_OPERAND (inner, 0))))) | |
738cc472 RK |
584 | return 0; |
585 | } | |
586 | ||
3d9b47dc AN |
587 | /* For non-addressable fields we return the alias set of the |
588 | outermost object that could have its address taken. If this | |
589 | is an SFT use the precomputed value. */ | |
590 | if (TREE_CODE (t) == STRUCT_FIELD_TAG | |
591 | && SFT_NONADDRESSABLE_P (t)) | |
592 | return SFT_ALIAS_SET (t); | |
593 | ||
738cc472 | 594 | /* Otherwise, pick up the outermost object that we could have a pointer |
6fce44af | 595 | to, processing conversions as above. */ |
2039d7aa | 596 | while (component_uses_parent_alias_set (t)) |
f47e9b4e | 597 | { |
6fce44af | 598 | t = TREE_OPERAND (t, 0); |
8ac61af7 RK |
599 | STRIP_NOPS (t); |
600 | } | |
f824e5c3 | 601 | |
738cc472 RK |
602 | /* If we've already determined the alias set for a decl, just return |
603 | it. This is necessary for C++ anonymous unions, whose component | |
604 | variables don't look like union members (boo!). */ | |
5755cd38 | 605 | if (TREE_CODE (t) == VAR_DECL |
3c0cb5de | 606 | && DECL_RTL_SET_P (t) && MEM_P (DECL_RTL (t))) |
5755cd38 JM |
607 | return MEM_ALIAS_SET (DECL_RTL (t)); |
608 | ||
f824e5c3 RK |
609 | /* Now all we care about is the type. */ |
610 | t = TREE_TYPE (t); | |
3bdf5ad1 RK |
611 | } |
612 | ||
3bdf5ad1 RK |
613 | /* Variant qualifiers don't affect the alias set, so get the main |
614 | variant. If this is a type with a known alias set, return it. */ | |
615 | t = TYPE_MAIN_VARIANT (t); | |
738cc472 | 616 | if (TYPE_ALIAS_SET_KNOWN_P (t)) |
3bdf5ad1 RK |
617 | return TYPE_ALIAS_SET (t); |
618 | ||
36784d0e RG |
619 | /* We don't want to set TYPE_ALIAS_SET for incomplete types. */ |
620 | if (!COMPLETE_TYPE_P (t)) | |
621 | { | |
622 | /* For arrays with unknown size the conservative answer is the | |
623 | alias set of the element type. */ | |
624 | if (TREE_CODE (t) == ARRAY_TYPE) | |
625 | return get_alias_set (TREE_TYPE (t)); | |
626 | ||
627 | /* But return zero as a conservative answer for incomplete types. */ | |
628 | return 0; | |
629 | } | |
630 | ||
3bdf5ad1 | 631 | /* See if the language has special handling for this type. */ |
ae2bcd98 | 632 | set = lang_hooks.get_alias_set (t); |
8ac61af7 | 633 | if (set != -1) |
738cc472 | 634 | return set; |
2bf105ab | 635 | |
3bdf5ad1 RK |
636 | /* There are no objects of FUNCTION_TYPE, so there's no point in |
637 | using up an alias set for them. (There are, of course, pointers | |
638 | and references to functions, but that's different.) */ | |
e11e491d RG |
639 | else if (TREE_CODE (t) == FUNCTION_TYPE |
640 | || TREE_CODE (t) == METHOD_TYPE) | |
3bdf5ad1 | 641 | set = 0; |
74d86f4f RH |
642 | |
643 | /* Unless the language specifies otherwise, let vector types alias | |
644 | their components. This avoids some nasty type punning issues in | |
645 | normal usage. And indeed lets vectors be treated more like an | |
646 | array slice. */ | |
647 | else if (TREE_CODE (t) == VECTOR_TYPE) | |
648 | set = get_alias_set (TREE_TYPE (t)); | |
649 | ||
3bdf5ad1 RK |
650 | else |
651 | /* Otherwise make a new alias set for this type. */ | |
652 | set = new_alias_set (); | |
653 | ||
654 | TYPE_ALIAS_SET (t) = set; | |
2bf105ab RK |
655 | |
656 | /* If this is an aggregate type, we must record any component aliasing | |
657 | information. */ | |
1d79fd2c | 658 | if (AGGREGATE_TYPE_P (t) || TREE_CODE (t) == COMPLEX_TYPE) |
2bf105ab RK |
659 | record_component_aliases (t); |
660 | ||
3bdf5ad1 RK |
661 | return set; |
662 | } | |
663 | ||
664 | /* Return a brand-new alias set. */ | |
665 | ||
4862826d | 666 | alias_set_type |
4682ae04 | 667 | new_alias_set (void) |
3bdf5ad1 | 668 | { |
3bdf5ad1 | 669 | if (flag_strict_aliasing) |
9ddb66ca | 670 | { |
1a5640b4 KH |
671 | if (alias_sets == 0) |
672 | VEC_safe_push (alias_set_entry, gc, alias_sets, 0); | |
673 | VEC_safe_push (alias_set_entry, gc, alias_sets, 0); | |
674 | return VEC_length (alias_set_entry, alias_sets) - 1; | |
9ddb66ca | 675 | } |
3bdf5ad1 RK |
676 | else |
677 | return 0; | |
678 | } | |
3932261a | 679 | |
01d28c3f JM |
680 | /* Indicate that things in SUBSET can alias things in SUPERSET, but that |
681 | not everything that aliases SUPERSET also aliases SUBSET. For example, | |
682 | in C, a store to an `int' can alias a load of a structure containing an | |
683 | `int', and vice versa. But it can't alias a load of a 'double' member | |
684 | of the same structure. Here, the structure would be the SUPERSET and | |
685 | `int' the SUBSET. This relationship is also described in the comment at | |
686 | the beginning of this file. | |
687 | ||
688 | This function should be called only once per SUPERSET/SUBSET pair. | |
3932261a MM |
689 | |
690 | It is illegal for SUPERSET to be zero; everything is implicitly a | |
691 | subset of alias set zero. */ | |
692 | ||
04e2b4d3 | 693 | static void |
4862826d | 694 | record_alias_subset (alias_set_type superset, alias_set_type subset) |
3932261a MM |
695 | { |
696 | alias_set_entry superset_entry; | |
697 | alias_set_entry subset_entry; | |
698 | ||
f47e9b4e RK |
699 | /* It is possible in complex type situations for both sets to be the same, |
700 | in which case we can ignore this operation. */ | |
701 | if (superset == subset) | |
702 | return; | |
703 | ||
298e6adc | 704 | gcc_assert (superset); |
3932261a MM |
705 | |
706 | superset_entry = get_alias_set_entry (superset); | |
ca7fd9cd | 707 | if (superset_entry == 0) |
3932261a MM |
708 | { |
709 | /* Create an entry for the SUPERSET, so that we have a place to | |
710 | attach the SUBSET. */ | |
b604074c | 711 | superset_entry = ggc_alloc (sizeof (struct alias_set_entry)); |
3932261a | 712 | superset_entry->alias_set = superset; |
ca7fd9cd | 713 | superset_entry->children |
b604074c | 714 | = splay_tree_new_ggc (splay_tree_compare_ints); |
570eb5c8 | 715 | superset_entry->has_zero_child = 0; |
1a5640b4 | 716 | VEC_replace (alias_set_entry, alias_sets, superset, superset_entry); |
3932261a MM |
717 | } |
718 | ||
2bf105ab RK |
719 | if (subset == 0) |
720 | superset_entry->has_zero_child = 1; | |
721 | else | |
722 | { | |
723 | subset_entry = get_alias_set_entry (subset); | |
724 | /* If there is an entry for the subset, enter all of its children | |
725 | (if they are not already present) as children of the SUPERSET. */ | |
ca7fd9cd | 726 | if (subset_entry) |
2bf105ab RK |
727 | { |
728 | if (subset_entry->has_zero_child) | |
729 | superset_entry->has_zero_child = 1; | |
d4b60170 | 730 | |
2bf105ab RK |
731 | splay_tree_foreach (subset_entry->children, insert_subset_children, |
732 | superset_entry->children); | |
733 | } | |
3932261a | 734 | |
2bf105ab | 735 | /* Enter the SUBSET itself as a child of the SUPERSET. */ |
ca7fd9cd | 736 | splay_tree_insert (superset_entry->children, |
2bf105ab RK |
737 | (splay_tree_key) subset, 0); |
738 | } | |
3932261a MM |
739 | } |
740 | ||
a0c33338 RK |
741 | /* Record that component types of TYPE, if any, are part of that type for |
742 | aliasing purposes. For record types, we only record component types | |
743 | for fields that are marked addressable. For array types, we always | |
744 | record the component types, so the front end should not call this | |
745 | function if the individual component aren't addressable. */ | |
746 | ||
747 | void | |
4682ae04 | 748 | record_component_aliases (tree type) |
a0c33338 | 749 | { |
4862826d | 750 | alias_set_type superset = get_alias_set (type); |
a0c33338 RK |
751 | tree field; |
752 | ||
753 | if (superset == 0) | |
754 | return; | |
755 | ||
756 | switch (TREE_CODE (type)) | |
757 | { | |
758 | case ARRAY_TYPE: | |
2bf105ab RK |
759 | if (! TYPE_NONALIASED_COMPONENT (type)) |
760 | record_alias_subset (superset, get_alias_set (TREE_TYPE (type))); | |
a0c33338 RK |
761 | break; |
762 | ||
763 | case RECORD_TYPE: | |
764 | case UNION_TYPE: | |
765 | case QUAL_UNION_TYPE: | |
6614fd40 | 766 | /* Recursively record aliases for the base classes, if there are any. */ |
fa743e8c | 767 | if (TYPE_BINFO (type)) |
ca7fd9cd KH |
768 | { |
769 | int i; | |
fa743e8c | 770 | tree binfo, base_binfo; |
c22cacf3 | 771 | |
fa743e8c NS |
772 | for (binfo = TYPE_BINFO (type), i = 0; |
773 | BINFO_BASE_ITERATE (binfo, i, base_binfo); i++) | |
774 | record_alias_subset (superset, | |
775 | get_alias_set (BINFO_TYPE (base_binfo))); | |
ca7fd9cd | 776 | } |
a0c33338 | 777 | for (field = TYPE_FIELDS (type); field != 0; field = TREE_CHAIN (field)) |
b16a49a1 | 778 | if (TREE_CODE (field) == FIELD_DECL && ! DECL_NONADDRESSABLE_P (field)) |
2bf105ab | 779 | record_alias_subset (superset, get_alias_set (TREE_TYPE (field))); |
a0c33338 RK |
780 | break; |
781 | ||
1d79fd2c JW |
782 | case COMPLEX_TYPE: |
783 | record_alias_subset (superset, get_alias_set (TREE_TYPE (type))); | |
784 | break; | |
785 | ||
a0c33338 RK |
786 | default: |
787 | break; | |
788 | } | |
789 | } | |
790 | ||
3bdf5ad1 RK |
791 | /* Allocate an alias set for use in storing and reading from the varargs |
792 | spill area. */ | |
793 | ||
4862826d | 794 | static GTY(()) alias_set_type varargs_set = -1; |
f103e34d | 795 | |
4862826d | 796 | alias_set_type |
4682ae04 | 797 | get_varargs_alias_set (void) |
3bdf5ad1 | 798 | { |
cd3ce9b4 JM |
799 | #if 1 |
800 | /* We now lower VA_ARG_EXPR, and there's currently no way to attach the | |
801 | varargs alias set to an INDIRECT_REF (FIXME!), so we can't | |
802 | consistently use the varargs alias set for loads from the varargs | |
803 | area. So don't use it anywhere. */ | |
804 | return 0; | |
805 | #else | |
f103e34d GK |
806 | if (varargs_set == -1) |
807 | varargs_set = new_alias_set (); | |
3bdf5ad1 | 808 | |
f103e34d | 809 | return varargs_set; |
cd3ce9b4 | 810 | #endif |
3bdf5ad1 RK |
811 | } |
812 | ||
813 | /* Likewise, but used for the fixed portions of the frame, e.g., register | |
814 | save areas. */ | |
815 | ||
4862826d | 816 | static GTY(()) alias_set_type frame_set = -1; |
f103e34d | 817 | |
4862826d | 818 | alias_set_type |
4682ae04 | 819 | get_frame_alias_set (void) |
3bdf5ad1 | 820 | { |
f103e34d GK |
821 | if (frame_set == -1) |
822 | frame_set = new_alias_set (); | |
3bdf5ad1 | 823 | |
f103e34d | 824 | return frame_set; |
3bdf5ad1 RK |
825 | } |
826 | ||
2a2c8203 JC |
827 | /* Inside SRC, the source of a SET, find a base address. */ |
828 | ||
9ae8ffe7 | 829 | static rtx |
4682ae04 | 830 | find_base_value (rtx src) |
9ae8ffe7 | 831 | { |
713f41f9 | 832 | unsigned int regno; |
0aacc8ed | 833 | |
9ae8ffe7 JL |
834 | switch (GET_CODE (src)) |
835 | { | |
836 | case SYMBOL_REF: | |
837 | case LABEL_REF: | |
838 | return src; | |
839 | ||
840 | case REG: | |
fb6754f0 | 841 | regno = REGNO (src); |
d4b60170 | 842 | /* At the start of a function, argument registers have known base |
2a2c8203 JC |
843 | values which may be lost later. Returning an ADDRESS |
844 | expression here allows optimization based on argument values | |
845 | even when the argument registers are used for other purposes. */ | |
713f41f9 BS |
846 | if (regno < FIRST_PSEUDO_REGISTER && copying_arguments) |
847 | return new_reg_base_value[regno]; | |
73774bc7 | 848 | |
eaf407a5 | 849 | /* If a pseudo has a known base value, return it. Do not do this |
9b462c42 RH |
850 | for non-fixed hard regs since it can result in a circular |
851 | dependency chain for registers which have values at function entry. | |
eaf407a5 JL |
852 | |
853 | The test above is not sufficient because the scheduler may move | |
854 | a copy out of an arg reg past the NOTE_INSN_FUNCTION_BEGIN. */ | |
9b462c42 | 855 | if ((regno >= FIRST_PSEUDO_REGISTER || fixed_regs[regno]) |
08c79682 | 856 | && regno < VEC_length (rtx, reg_base_value)) |
83bbd9b6 RH |
857 | { |
858 | /* If we're inside init_alias_analysis, use new_reg_base_value | |
859 | to reduce the number of relaxation iterations. */ | |
1afdf91c | 860 | if (new_reg_base_value && new_reg_base_value[regno] |
6fb5fa3c | 861 | && DF_REG_DEF_COUNT (regno) == 1) |
83bbd9b6 RH |
862 | return new_reg_base_value[regno]; |
863 | ||
08c79682 KH |
864 | if (VEC_index (rtx, reg_base_value, regno)) |
865 | return VEC_index (rtx, reg_base_value, regno); | |
83bbd9b6 | 866 | } |
73774bc7 | 867 | |
e3f049a8 | 868 | return 0; |
9ae8ffe7 JL |
869 | |
870 | case MEM: | |
871 | /* Check for an argument passed in memory. Only record in the | |
872 | copying-arguments block; it is too hard to track changes | |
873 | otherwise. */ | |
874 | if (copying_arguments | |
875 | && (XEXP (src, 0) == arg_pointer_rtx | |
876 | || (GET_CODE (XEXP (src, 0)) == PLUS | |
877 | && XEXP (XEXP (src, 0), 0) == arg_pointer_rtx))) | |
38a448ca | 878 | return gen_rtx_ADDRESS (VOIDmode, src); |
9ae8ffe7 JL |
879 | return 0; |
880 | ||
881 | case CONST: | |
882 | src = XEXP (src, 0); | |
883 | if (GET_CODE (src) != PLUS && GET_CODE (src) != MINUS) | |
884 | break; | |
d4b60170 | 885 | |
ec5c56db | 886 | /* ... fall through ... */ |
2a2c8203 | 887 | |
9ae8ffe7 JL |
888 | case PLUS: |
889 | case MINUS: | |
2a2c8203 | 890 | { |
ec907dd8 JL |
891 | rtx temp, src_0 = XEXP (src, 0), src_1 = XEXP (src, 1); |
892 | ||
0134bf2d DE |
893 | /* If either operand is a REG that is a known pointer, then it |
894 | is the base. */ | |
895 | if (REG_P (src_0) && REG_POINTER (src_0)) | |
896 | return find_base_value (src_0); | |
897 | if (REG_P (src_1) && REG_POINTER (src_1)) | |
898 | return find_base_value (src_1); | |
899 | ||
ec907dd8 JL |
900 | /* If either operand is a REG, then see if we already have |
901 | a known value for it. */ | |
0134bf2d | 902 | if (REG_P (src_0)) |
ec907dd8 JL |
903 | { |
904 | temp = find_base_value (src_0); | |
d4b60170 | 905 | if (temp != 0) |
ec907dd8 JL |
906 | src_0 = temp; |
907 | } | |
908 | ||
0134bf2d | 909 | if (REG_P (src_1)) |
ec907dd8 JL |
910 | { |
911 | temp = find_base_value (src_1); | |
d4b60170 | 912 | if (temp!= 0) |
ec907dd8 JL |
913 | src_1 = temp; |
914 | } | |
2a2c8203 | 915 | |
0134bf2d DE |
916 | /* If either base is named object or a special address |
917 | (like an argument or stack reference), then use it for the | |
918 | base term. */ | |
919 | if (src_0 != 0 | |
920 | && (GET_CODE (src_0) == SYMBOL_REF | |
921 | || GET_CODE (src_0) == LABEL_REF | |
922 | || (GET_CODE (src_0) == ADDRESS | |
923 | && GET_MODE (src_0) != VOIDmode))) | |
924 | return src_0; | |
925 | ||
926 | if (src_1 != 0 | |
927 | && (GET_CODE (src_1) == SYMBOL_REF | |
928 | || GET_CODE (src_1) == LABEL_REF | |
929 | || (GET_CODE (src_1) == ADDRESS | |
930 | && GET_MODE (src_1) != VOIDmode))) | |
931 | return src_1; | |
932 | ||
d4b60170 | 933 | /* Guess which operand is the base address: |
ec907dd8 JL |
934 | If either operand is a symbol, then it is the base. If |
935 | either operand is a CONST_INT, then the other is the base. */ | |
d4b60170 | 936 | if (GET_CODE (src_1) == CONST_INT || CONSTANT_P (src_0)) |
2a2c8203 | 937 | return find_base_value (src_0); |
d4b60170 | 938 | else if (GET_CODE (src_0) == CONST_INT || CONSTANT_P (src_1)) |
ec907dd8 JL |
939 | return find_base_value (src_1); |
940 | ||
9ae8ffe7 | 941 | return 0; |
2a2c8203 JC |
942 | } |
943 | ||
944 | case LO_SUM: | |
945 | /* The standard form is (lo_sum reg sym) so look only at the | |
946 | second operand. */ | |
947 | return find_base_value (XEXP (src, 1)); | |
9ae8ffe7 JL |
948 | |
949 | case AND: | |
950 | /* If the second operand is constant set the base | |
ec5c56db | 951 | address to the first operand. */ |
2a2c8203 JC |
952 | if (GET_CODE (XEXP (src, 1)) == CONST_INT && INTVAL (XEXP (src, 1)) != 0) |
953 | return find_base_value (XEXP (src, 0)); | |
9ae8ffe7 JL |
954 | return 0; |
955 | ||
61f0131c R |
956 | case TRUNCATE: |
957 | if (GET_MODE_SIZE (GET_MODE (src)) < GET_MODE_SIZE (Pmode)) | |
958 | break; | |
959 | /* Fall through. */ | |
9ae8ffe7 | 960 | case HIGH: |
d288e53d DE |
961 | case PRE_INC: |
962 | case PRE_DEC: | |
963 | case POST_INC: | |
964 | case POST_DEC: | |
965 | case PRE_MODIFY: | |
966 | case POST_MODIFY: | |
2a2c8203 | 967 | return find_base_value (XEXP (src, 0)); |
1d300e19 | 968 | |
0aacc8ed RK |
969 | case ZERO_EXTEND: |
970 | case SIGN_EXTEND: /* used for NT/Alpha pointers */ | |
971 | { | |
972 | rtx temp = find_base_value (XEXP (src, 0)); | |
973 | ||
5ae6cd0d | 974 | if (temp != 0 && CONSTANT_P (temp)) |
0aacc8ed | 975 | temp = convert_memory_address (Pmode, temp); |
0aacc8ed RK |
976 | |
977 | return temp; | |
978 | } | |
979 | ||
1d300e19 KG |
980 | default: |
981 | break; | |
9ae8ffe7 JL |
982 | } |
983 | ||
984 | return 0; | |
985 | } | |
986 | ||
987 | /* Called from init_alias_analysis indirectly through note_stores. */ | |
988 | ||
d4b60170 | 989 | /* While scanning insns to find base values, reg_seen[N] is nonzero if |
9ae8ffe7 JL |
990 | register N has been set in this function. */ |
991 | static char *reg_seen; | |
992 | ||
13309a5f JC |
993 | /* Addresses which are known not to alias anything else are identified |
994 | by a unique integer. */ | |
ec907dd8 JL |
995 | static int unique_id; |
996 | ||
2a2c8203 | 997 | static void |
7bc980e1 | 998 | record_set (rtx dest, const_rtx set, void *data ATTRIBUTE_UNUSED) |
9ae8ffe7 | 999 | { |
b3694847 | 1000 | unsigned regno; |
9ae8ffe7 | 1001 | rtx src; |
c28b4e40 | 1002 | int n; |
9ae8ffe7 | 1003 | |
f8cfc6aa | 1004 | if (!REG_P (dest)) |
9ae8ffe7 JL |
1005 | return; |
1006 | ||
fb6754f0 | 1007 | regno = REGNO (dest); |
9ae8ffe7 | 1008 | |
08c79682 | 1009 | gcc_assert (regno < VEC_length (rtx, reg_base_value)); |
ac606739 | 1010 | |
c28b4e40 JW |
1011 | /* If this spans multiple hard registers, then we must indicate that every |
1012 | register has an unusable value. */ | |
1013 | if (regno < FIRST_PSEUDO_REGISTER) | |
66fd46b6 | 1014 | n = hard_regno_nregs[regno][GET_MODE (dest)]; |
c28b4e40 JW |
1015 | else |
1016 | n = 1; | |
1017 | if (n != 1) | |
1018 | { | |
1019 | while (--n >= 0) | |
1020 | { | |
1021 | reg_seen[regno + n] = 1; | |
1022 | new_reg_base_value[regno + n] = 0; | |
1023 | } | |
1024 | return; | |
1025 | } | |
1026 | ||
9ae8ffe7 JL |
1027 | if (set) |
1028 | { | |
1029 | /* A CLOBBER wipes out any old value but does not prevent a previously | |
1030 | unset register from acquiring a base address (i.e. reg_seen is not | |
1031 | set). */ | |
1032 | if (GET_CODE (set) == CLOBBER) | |
1033 | { | |
ec907dd8 | 1034 | new_reg_base_value[regno] = 0; |
9ae8ffe7 JL |
1035 | return; |
1036 | } | |
1037 | src = SET_SRC (set); | |
1038 | } | |
1039 | else | |
1040 | { | |
9ae8ffe7 JL |
1041 | if (reg_seen[regno]) |
1042 | { | |
ec907dd8 | 1043 | new_reg_base_value[regno] = 0; |
9ae8ffe7 JL |
1044 | return; |
1045 | } | |
1046 | reg_seen[regno] = 1; | |
38a448ca RH |
1047 | new_reg_base_value[regno] = gen_rtx_ADDRESS (Pmode, |
1048 | GEN_INT (unique_id++)); | |
9ae8ffe7 JL |
1049 | return; |
1050 | } | |
1051 | ||
5da6f168 RS |
1052 | /* If this is not the first set of REGNO, see whether the new value |
1053 | is related to the old one. There are two cases of interest: | |
1054 | ||
1055 | (1) The register might be assigned an entirely new value | |
1056 | that has the same base term as the original set. | |
1057 | ||
1058 | (2) The set might be a simple self-modification that | |
1059 | cannot change REGNO's base value. | |
1060 | ||
1061 | If neither case holds, reject the original base value as invalid. | |
1062 | Note that the following situation is not detected: | |
1063 | ||
c22cacf3 | 1064 | extern int x, y; int *p = &x; p += (&y-&x); |
5da6f168 | 1065 | |
9ae8ffe7 JL |
1066 | ANSI C does not allow computing the difference of addresses |
1067 | of distinct top level objects. */ | |
5da6f168 RS |
1068 | if (new_reg_base_value[regno] != 0 |
1069 | && find_base_value (src) != new_reg_base_value[regno]) | |
9ae8ffe7 JL |
1070 | switch (GET_CODE (src)) |
1071 | { | |
2a2c8203 | 1072 | case LO_SUM: |
9ae8ffe7 JL |
1073 | case MINUS: |
1074 | if (XEXP (src, 0) != dest && XEXP (src, 1) != dest) | |
ec907dd8 | 1075 | new_reg_base_value[regno] = 0; |
9ae8ffe7 | 1076 | break; |
61f0131c R |
1077 | case PLUS: |
1078 | /* If the value we add in the PLUS is also a valid base value, | |
1079 | this might be the actual base value, and the original value | |
1080 | an index. */ | |
1081 | { | |
1082 | rtx other = NULL_RTX; | |
1083 | ||
1084 | if (XEXP (src, 0) == dest) | |
1085 | other = XEXP (src, 1); | |
1086 | else if (XEXP (src, 1) == dest) | |
1087 | other = XEXP (src, 0); | |
1088 | ||
1089 | if (! other || find_base_value (other)) | |
1090 | new_reg_base_value[regno] = 0; | |
1091 | break; | |
1092 | } | |
9ae8ffe7 JL |
1093 | case AND: |
1094 | if (XEXP (src, 0) != dest || GET_CODE (XEXP (src, 1)) != CONST_INT) | |
ec907dd8 | 1095 | new_reg_base_value[regno] = 0; |
9ae8ffe7 | 1096 | break; |
9ae8ffe7 | 1097 | default: |
ec907dd8 | 1098 | new_reg_base_value[regno] = 0; |
9ae8ffe7 JL |
1099 | break; |
1100 | } | |
1101 | /* If this is the first set of a register, record the value. */ | |
1102 | else if ((regno >= FIRST_PSEUDO_REGISTER || ! fixed_regs[regno]) | |
ec907dd8 JL |
1103 | && ! reg_seen[regno] && new_reg_base_value[regno] == 0) |
1104 | new_reg_base_value[regno] = find_base_value (src); | |
9ae8ffe7 JL |
1105 | |
1106 | reg_seen[regno] = 1; | |
1107 | } | |
1108 | ||
bb1acb3e RH |
1109 | /* If a value is known for REGNO, return it. */ |
1110 | ||
c22cacf3 | 1111 | rtx |
bb1acb3e RH |
1112 | get_reg_known_value (unsigned int regno) |
1113 | { | |
1114 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1115 | { | |
1116 | regno -= FIRST_PSEUDO_REGISTER; | |
1117 | if (regno < reg_known_value_size) | |
1118 | return reg_known_value[regno]; | |
1119 | } | |
1120 | return NULL; | |
43fe47ca JW |
1121 | } |
1122 | ||
bb1acb3e RH |
1123 | /* Set it. */ |
1124 | ||
1125 | static void | |
1126 | set_reg_known_value (unsigned int regno, rtx val) | |
1127 | { | |
1128 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1129 | { | |
1130 | regno -= FIRST_PSEUDO_REGISTER; | |
1131 | if (regno < reg_known_value_size) | |
1132 | reg_known_value[regno] = val; | |
1133 | } | |
1134 | } | |
1135 | ||
1136 | /* Similarly for reg_known_equiv_p. */ | |
1137 | ||
1138 | bool | |
1139 | get_reg_known_equiv_p (unsigned int regno) | |
1140 | { | |
1141 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1142 | { | |
1143 | regno -= FIRST_PSEUDO_REGISTER; | |
1144 | if (regno < reg_known_value_size) | |
1145 | return reg_known_equiv_p[regno]; | |
1146 | } | |
1147 | return false; | |
1148 | } | |
1149 | ||
1150 | static void | |
1151 | set_reg_known_equiv_p (unsigned int regno, bool val) | |
1152 | { | |
1153 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1154 | { | |
1155 | regno -= FIRST_PSEUDO_REGISTER; | |
1156 | if (regno < reg_known_value_size) | |
1157 | reg_known_equiv_p[regno] = val; | |
1158 | } | |
1159 | } | |
1160 | ||
1161 | ||
db048faf MM |
1162 | /* Returns a canonical version of X, from the point of view alias |
1163 | analysis. (For example, if X is a MEM whose address is a register, | |
1164 | and the register has a known value (say a SYMBOL_REF), then a MEM | |
1165 | whose address is the SYMBOL_REF is returned.) */ | |
1166 | ||
1167 | rtx | |
4682ae04 | 1168 | canon_rtx (rtx x) |
9ae8ffe7 JL |
1169 | { |
1170 | /* Recursively look for equivalences. */ | |
f8cfc6aa | 1171 | if (REG_P (x) && REGNO (x) >= FIRST_PSEUDO_REGISTER) |
bb1acb3e RH |
1172 | { |
1173 | rtx t = get_reg_known_value (REGNO (x)); | |
1174 | if (t == x) | |
1175 | return x; | |
1176 | if (t) | |
1177 | return canon_rtx (t); | |
1178 | } | |
1179 | ||
1180 | if (GET_CODE (x) == PLUS) | |
9ae8ffe7 JL |
1181 | { |
1182 | rtx x0 = canon_rtx (XEXP (x, 0)); | |
1183 | rtx x1 = canon_rtx (XEXP (x, 1)); | |
1184 | ||
1185 | if (x0 != XEXP (x, 0) || x1 != XEXP (x, 1)) | |
1186 | { | |
9ae8ffe7 | 1187 | if (GET_CODE (x0) == CONST_INT) |
ed8908e7 | 1188 | return plus_constant (x1, INTVAL (x0)); |
9ae8ffe7 | 1189 | else if (GET_CODE (x1) == CONST_INT) |
ed8908e7 | 1190 | return plus_constant (x0, INTVAL (x1)); |
38a448ca | 1191 | return gen_rtx_PLUS (GET_MODE (x), x0, x1); |
9ae8ffe7 JL |
1192 | } |
1193 | } | |
d4b60170 | 1194 | |
9ae8ffe7 JL |
1195 | /* This gives us much better alias analysis when called from |
1196 | the loop optimizer. Note we want to leave the original | |
1197 | MEM alone, but need to return the canonicalized MEM with | |
1198 | all the flags with their original values. */ | |
3c0cb5de | 1199 | else if (MEM_P (x)) |
f1ec5147 | 1200 | x = replace_equiv_address_nv (x, canon_rtx (XEXP (x, 0))); |
d4b60170 | 1201 | |
9ae8ffe7 JL |
1202 | return x; |
1203 | } | |
1204 | ||
1205 | /* Return 1 if X and Y are identical-looking rtx's. | |
45183e03 | 1206 | Expect that X and Y has been already canonicalized. |
9ae8ffe7 JL |
1207 | |
1208 | We use the data in reg_known_value above to see if two registers with | |
1209 | different numbers are, in fact, equivalent. */ | |
1210 | ||
1211 | static int | |
ed7a4b4b | 1212 | rtx_equal_for_memref_p (const_rtx x, const_rtx y) |
9ae8ffe7 | 1213 | { |
b3694847 SS |
1214 | int i; |
1215 | int j; | |
1216 | enum rtx_code code; | |
1217 | const char *fmt; | |
9ae8ffe7 JL |
1218 | |
1219 | if (x == 0 && y == 0) | |
1220 | return 1; | |
1221 | if (x == 0 || y == 0) | |
1222 | return 0; | |
d4b60170 | 1223 | |
9ae8ffe7 JL |
1224 | if (x == y) |
1225 | return 1; | |
1226 | ||
1227 | code = GET_CODE (x); | |
1228 | /* Rtx's of different codes cannot be equal. */ | |
1229 | if (code != GET_CODE (y)) | |
1230 | return 0; | |
1231 | ||
1232 | /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. | |
1233 | (REG:SI x) and (REG:HI x) are NOT equivalent. */ | |
1234 | ||
1235 | if (GET_MODE (x) != GET_MODE (y)) | |
1236 | return 0; | |
1237 | ||
db048faf MM |
1238 | /* Some RTL can be compared without a recursive examination. */ |
1239 | switch (code) | |
1240 | { | |
1241 | case REG: | |
1242 | return REGNO (x) == REGNO (y); | |
1243 | ||
1244 | case LABEL_REF: | |
1245 | return XEXP (x, 0) == XEXP (y, 0); | |
ca7fd9cd | 1246 | |
db048faf MM |
1247 | case SYMBOL_REF: |
1248 | return XSTR (x, 0) == XSTR (y, 0); | |
1249 | ||
40e02b4a | 1250 | case VALUE: |
db048faf MM |
1251 | case CONST_INT: |
1252 | case CONST_DOUBLE: | |
091a3ac7 | 1253 | case CONST_FIXED: |
db048faf MM |
1254 | /* There's no need to compare the contents of CONST_DOUBLEs or |
1255 | CONST_INTs because pointer equality is a good enough | |
1256 | comparison for these nodes. */ | |
1257 | return 0; | |
1258 | ||
db048faf MM |
1259 | default: |
1260 | break; | |
1261 | } | |
9ae8ffe7 | 1262 | |
45183e03 JH |
1263 | /* canon_rtx knows how to handle plus. No need to canonicalize. */ |
1264 | if (code == PLUS) | |
9ae8ffe7 JL |
1265 | return ((rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 0)) |
1266 | && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 1))) | |
1267 | || (rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 1)) | |
1268 | && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 0)))); | |
45183e03 JH |
1269 | /* For commutative operations, the RTX match if the operand match in any |
1270 | order. Also handle the simple binary and unary cases without a loop. */ | |
ec8e098d | 1271 | if (COMMUTATIVE_P (x)) |
45183e03 JH |
1272 | { |
1273 | rtx xop0 = canon_rtx (XEXP (x, 0)); | |
1274 | rtx yop0 = canon_rtx (XEXP (y, 0)); | |
1275 | rtx yop1 = canon_rtx (XEXP (y, 1)); | |
1276 | ||
1277 | return ((rtx_equal_for_memref_p (xop0, yop0) | |
1278 | && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), yop1)) | |
1279 | || (rtx_equal_for_memref_p (xop0, yop1) | |
1280 | && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), yop0))); | |
1281 | } | |
ec8e098d | 1282 | else if (NON_COMMUTATIVE_P (x)) |
45183e03 JH |
1283 | { |
1284 | return (rtx_equal_for_memref_p (canon_rtx (XEXP (x, 0)), | |
4682ae04 | 1285 | canon_rtx (XEXP (y, 0))) |
45183e03 JH |
1286 | && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), |
1287 | canon_rtx (XEXP (y, 1)))); | |
1288 | } | |
ec8e098d | 1289 | else if (UNARY_P (x)) |
45183e03 | 1290 | return rtx_equal_for_memref_p (canon_rtx (XEXP (x, 0)), |
4682ae04 | 1291 | canon_rtx (XEXP (y, 0))); |
9ae8ffe7 JL |
1292 | |
1293 | /* Compare the elements. If any pair of corresponding elements | |
de12be17 JC |
1294 | fail to match, return 0 for the whole things. |
1295 | ||
1296 | Limit cases to types which actually appear in addresses. */ | |
9ae8ffe7 JL |
1297 | |
1298 | fmt = GET_RTX_FORMAT (code); | |
1299 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
1300 | { | |
1301 | switch (fmt[i]) | |
1302 | { | |
9ae8ffe7 JL |
1303 | case 'i': |
1304 | if (XINT (x, i) != XINT (y, i)) | |
1305 | return 0; | |
1306 | break; | |
1307 | ||
9ae8ffe7 JL |
1308 | case 'E': |
1309 | /* Two vectors must have the same length. */ | |
1310 | if (XVECLEN (x, i) != XVECLEN (y, i)) | |
1311 | return 0; | |
1312 | ||
1313 | /* And the corresponding elements must match. */ | |
1314 | for (j = 0; j < XVECLEN (x, i); j++) | |
45183e03 JH |
1315 | if (rtx_equal_for_memref_p (canon_rtx (XVECEXP (x, i, j)), |
1316 | canon_rtx (XVECEXP (y, i, j))) == 0) | |
9ae8ffe7 JL |
1317 | return 0; |
1318 | break; | |
1319 | ||
1320 | case 'e': | |
45183e03 JH |
1321 | if (rtx_equal_for_memref_p (canon_rtx (XEXP (x, i)), |
1322 | canon_rtx (XEXP (y, i))) == 0) | |
9ae8ffe7 JL |
1323 | return 0; |
1324 | break; | |
1325 | ||
3237ac18 AH |
1326 | /* This can happen for asm operands. */ |
1327 | case 's': | |
1328 | if (strcmp (XSTR (x, i), XSTR (y, i))) | |
1329 | return 0; | |
1330 | break; | |
1331 | ||
aee21ba9 JL |
1332 | /* This can happen for an asm which clobbers memory. */ |
1333 | case '0': | |
1334 | break; | |
1335 | ||
9ae8ffe7 JL |
1336 | /* It is believed that rtx's at this level will never |
1337 | contain anything but integers and other rtx's, | |
1338 | except for within LABEL_REFs and SYMBOL_REFs. */ | |
1339 | default: | |
298e6adc | 1340 | gcc_unreachable (); |
9ae8ffe7 JL |
1341 | } |
1342 | } | |
1343 | return 1; | |
1344 | } | |
1345 | ||
94f24ddc | 1346 | rtx |
4682ae04 | 1347 | find_base_term (rtx x) |
9ae8ffe7 | 1348 | { |
eab5c70a BS |
1349 | cselib_val *val; |
1350 | struct elt_loc_list *l; | |
1351 | ||
b949ea8b JW |
1352 | #if defined (FIND_BASE_TERM) |
1353 | /* Try machine-dependent ways to find the base term. */ | |
1354 | x = FIND_BASE_TERM (x); | |
1355 | #endif | |
1356 | ||
9ae8ffe7 JL |
1357 | switch (GET_CODE (x)) |
1358 | { | |
1359 | case REG: | |
1360 | return REG_BASE_VALUE (x); | |
1361 | ||
d288e53d DE |
1362 | case TRUNCATE: |
1363 | if (GET_MODE_SIZE (GET_MODE (x)) < GET_MODE_SIZE (Pmode)) | |
ca7fd9cd | 1364 | return 0; |
d288e53d | 1365 | /* Fall through. */ |
9ae8ffe7 | 1366 | case HIGH: |
6d849a2a JL |
1367 | case PRE_INC: |
1368 | case PRE_DEC: | |
1369 | case POST_INC: | |
1370 | case POST_DEC: | |
d288e53d DE |
1371 | case PRE_MODIFY: |
1372 | case POST_MODIFY: | |
6d849a2a JL |
1373 | return find_base_term (XEXP (x, 0)); |
1374 | ||
1abade85 RK |
1375 | case ZERO_EXTEND: |
1376 | case SIGN_EXTEND: /* Used for Alpha/NT pointers */ | |
1377 | { | |
1378 | rtx temp = find_base_term (XEXP (x, 0)); | |
1379 | ||
5ae6cd0d | 1380 | if (temp != 0 && CONSTANT_P (temp)) |
1abade85 | 1381 | temp = convert_memory_address (Pmode, temp); |
1abade85 RK |
1382 | |
1383 | return temp; | |
1384 | } | |
1385 | ||
eab5c70a BS |
1386 | case VALUE: |
1387 | val = CSELIB_VAL_PTR (x); | |
40e02b4a JH |
1388 | if (!val) |
1389 | return 0; | |
eab5c70a BS |
1390 | for (l = val->locs; l; l = l->next) |
1391 | if ((x = find_base_term (l->loc)) != 0) | |
1392 | return x; | |
1393 | return 0; | |
1394 | ||
9ae8ffe7 JL |
1395 | case CONST: |
1396 | x = XEXP (x, 0); | |
1397 | if (GET_CODE (x) != PLUS && GET_CODE (x) != MINUS) | |
1398 | return 0; | |
938d968e | 1399 | /* Fall through. */ |
9ae8ffe7 JL |
1400 | case LO_SUM: |
1401 | case PLUS: | |
1402 | case MINUS: | |
1403 | { | |
3c567fae JL |
1404 | rtx tmp1 = XEXP (x, 0); |
1405 | rtx tmp2 = XEXP (x, 1); | |
1406 | ||
f5143c46 | 1407 | /* This is a little bit tricky since we have to determine which of |
3c567fae JL |
1408 | the two operands represents the real base address. Otherwise this |
1409 | routine may return the index register instead of the base register. | |
1410 | ||
1411 | That may cause us to believe no aliasing was possible, when in | |
1412 | fact aliasing is possible. | |
1413 | ||
1414 | We use a few simple tests to guess the base register. Additional | |
1415 | tests can certainly be added. For example, if one of the operands | |
1416 | is a shift or multiply, then it must be the index register and the | |
1417 | other operand is the base register. */ | |
ca7fd9cd | 1418 | |
b949ea8b JW |
1419 | if (tmp1 == pic_offset_table_rtx && CONSTANT_P (tmp2)) |
1420 | return find_base_term (tmp2); | |
1421 | ||
3c567fae JL |
1422 | /* If either operand is known to be a pointer, then use it |
1423 | to determine the base term. */ | |
3502dc9c | 1424 | if (REG_P (tmp1) && REG_POINTER (tmp1)) |
3c567fae JL |
1425 | return find_base_term (tmp1); |
1426 | ||
3502dc9c | 1427 | if (REG_P (tmp2) && REG_POINTER (tmp2)) |
3c567fae JL |
1428 | return find_base_term (tmp2); |
1429 | ||
1430 | /* Neither operand was known to be a pointer. Go ahead and find the | |
1431 | base term for both operands. */ | |
1432 | tmp1 = find_base_term (tmp1); | |
1433 | tmp2 = find_base_term (tmp2); | |
1434 | ||
1435 | /* If either base term is named object or a special address | |
1436 | (like an argument or stack reference), then use it for the | |
1437 | base term. */ | |
d4b60170 | 1438 | if (tmp1 != 0 |
3c567fae JL |
1439 | && (GET_CODE (tmp1) == SYMBOL_REF |
1440 | || GET_CODE (tmp1) == LABEL_REF | |
1441 | || (GET_CODE (tmp1) == ADDRESS | |
1442 | && GET_MODE (tmp1) != VOIDmode))) | |
1443 | return tmp1; | |
1444 | ||
d4b60170 | 1445 | if (tmp2 != 0 |
3c567fae JL |
1446 | && (GET_CODE (tmp2) == SYMBOL_REF |
1447 | || GET_CODE (tmp2) == LABEL_REF | |
1448 | || (GET_CODE (tmp2) == ADDRESS | |
1449 | && GET_MODE (tmp2) != VOIDmode))) | |
1450 | return tmp2; | |
1451 | ||
1452 | /* We could not determine which of the two operands was the | |
1453 | base register and which was the index. So we can determine | |
1454 | nothing from the base alias check. */ | |
1455 | return 0; | |
9ae8ffe7 JL |
1456 | } |
1457 | ||
1458 | case AND: | |
d288e53d DE |
1459 | if (GET_CODE (XEXP (x, 1)) == CONST_INT && INTVAL (XEXP (x, 1)) != 0) |
1460 | return find_base_term (XEXP (x, 0)); | |
9ae8ffe7 JL |
1461 | return 0; |
1462 | ||
1463 | case SYMBOL_REF: | |
1464 | case LABEL_REF: | |
1465 | return x; | |
1466 | ||
1467 | default: | |
1468 | return 0; | |
1469 | } | |
1470 | } | |
1471 | ||
1472 | /* Return 0 if the addresses X and Y are known to point to different | |
1473 | objects, 1 if they might be pointers to the same object. */ | |
1474 | ||
1475 | static int | |
4682ae04 AJ |
1476 | base_alias_check (rtx x, rtx y, enum machine_mode x_mode, |
1477 | enum machine_mode y_mode) | |
9ae8ffe7 JL |
1478 | { |
1479 | rtx x_base = find_base_term (x); | |
1480 | rtx y_base = find_base_term (y); | |
1481 | ||
1c72c7f6 JC |
1482 | /* If the address itself has no known base see if a known equivalent |
1483 | value has one. If either address still has no known base, nothing | |
1484 | is known about aliasing. */ | |
1485 | if (x_base == 0) | |
1486 | { | |
1487 | rtx x_c; | |
d4b60170 | 1488 | |
1c72c7f6 JC |
1489 | if (! flag_expensive_optimizations || (x_c = canon_rtx (x)) == x) |
1490 | return 1; | |
d4b60170 | 1491 | |
1c72c7f6 JC |
1492 | x_base = find_base_term (x_c); |
1493 | if (x_base == 0) | |
1494 | return 1; | |
1495 | } | |
9ae8ffe7 | 1496 | |
1c72c7f6 JC |
1497 | if (y_base == 0) |
1498 | { | |
1499 | rtx y_c; | |
1500 | if (! flag_expensive_optimizations || (y_c = canon_rtx (y)) == y) | |
1501 | return 1; | |
d4b60170 | 1502 | |
1c72c7f6 JC |
1503 | y_base = find_base_term (y_c); |
1504 | if (y_base == 0) | |
1505 | return 1; | |
1506 | } | |
1507 | ||
1508 | /* If the base addresses are equal nothing is known about aliasing. */ | |
1509 | if (rtx_equal_p (x_base, y_base)) | |
9ae8ffe7 JL |
1510 | return 1; |
1511 | ||
ca7fd9cd | 1512 | /* The base addresses of the read and write are different expressions. |
56ee9281 RH |
1513 | If they are both symbols and they are not accessed via AND, there is |
1514 | no conflict. We can bring knowledge of object alignment into play | |
1515 | here. For example, on alpha, "char a, b;" can alias one another, | |
1516 | though "char a; long b;" cannot. */ | |
9ae8ffe7 | 1517 | if (GET_CODE (x_base) != ADDRESS && GET_CODE (y_base) != ADDRESS) |
c02f035f | 1518 | { |
56ee9281 RH |
1519 | if (GET_CODE (x) == AND && GET_CODE (y) == AND) |
1520 | return 1; | |
1521 | if (GET_CODE (x) == AND | |
1522 | && (GET_CODE (XEXP (x, 1)) != CONST_INT | |
8fa2140d | 1523 | || (int) GET_MODE_UNIT_SIZE (y_mode) < -INTVAL (XEXP (x, 1)))) |
56ee9281 RH |
1524 | return 1; |
1525 | if (GET_CODE (y) == AND | |
1526 | && (GET_CODE (XEXP (y, 1)) != CONST_INT | |
8fa2140d | 1527 | || (int) GET_MODE_UNIT_SIZE (x_mode) < -INTVAL (XEXP (y, 1)))) |
56ee9281 | 1528 | return 1; |
b2972551 JL |
1529 | /* Differing symbols never alias. */ |
1530 | return 0; | |
c02f035f | 1531 | } |
9ae8ffe7 JL |
1532 | |
1533 | /* If one address is a stack reference there can be no alias: | |
1534 | stack references using different base registers do not alias, | |
1535 | a stack reference can not alias a parameter, and a stack reference | |
1536 | can not alias a global. */ | |
1537 | if ((GET_CODE (x_base) == ADDRESS && GET_MODE (x_base) == Pmode) | |
1538 | || (GET_CODE (y_base) == ADDRESS && GET_MODE (y_base) == Pmode)) | |
1539 | return 0; | |
1540 | ||
1541 | if (! flag_argument_noalias) | |
1542 | return 1; | |
1543 | ||
1544 | if (flag_argument_noalias > 1) | |
1545 | return 0; | |
1546 | ||
ec5c56db | 1547 | /* Weak noalias assertion (arguments are distinct, but may match globals). */ |
9ae8ffe7 JL |
1548 | return ! (GET_MODE (x_base) == VOIDmode && GET_MODE (y_base) == VOIDmode); |
1549 | } | |
1550 | ||
eab5c70a BS |
1551 | /* Convert the address X into something we can use. This is done by returning |
1552 | it unchanged unless it is a value; in the latter case we call cselib to get | |
1553 | a more useful rtx. */ | |
3bdf5ad1 | 1554 | |
a13d4ebf | 1555 | rtx |
4682ae04 | 1556 | get_addr (rtx x) |
eab5c70a BS |
1557 | { |
1558 | cselib_val *v; | |
1559 | struct elt_loc_list *l; | |
1560 | ||
1561 | if (GET_CODE (x) != VALUE) | |
1562 | return x; | |
1563 | v = CSELIB_VAL_PTR (x); | |
40e02b4a JH |
1564 | if (v) |
1565 | { | |
1566 | for (l = v->locs; l; l = l->next) | |
1567 | if (CONSTANT_P (l->loc)) | |
1568 | return l->loc; | |
1569 | for (l = v->locs; l; l = l->next) | |
3c0cb5de | 1570 | if (!REG_P (l->loc) && !MEM_P (l->loc)) |
40e02b4a JH |
1571 | return l->loc; |
1572 | if (v->locs) | |
1573 | return v->locs->loc; | |
1574 | } | |
eab5c70a BS |
1575 | return x; |
1576 | } | |
1577 | ||
39cec1ac MH |
1578 | /* Return the address of the (N_REFS + 1)th memory reference to ADDR |
1579 | where SIZE is the size in bytes of the memory reference. If ADDR | |
1580 | is not modified by the memory reference then ADDR is returned. */ | |
1581 | ||
04e2b4d3 | 1582 | static rtx |
4682ae04 | 1583 | addr_side_effect_eval (rtx addr, int size, int n_refs) |
39cec1ac MH |
1584 | { |
1585 | int offset = 0; | |
ca7fd9cd | 1586 | |
39cec1ac MH |
1587 | switch (GET_CODE (addr)) |
1588 | { | |
1589 | case PRE_INC: | |
1590 | offset = (n_refs + 1) * size; | |
1591 | break; | |
1592 | case PRE_DEC: | |
1593 | offset = -(n_refs + 1) * size; | |
1594 | break; | |
1595 | case POST_INC: | |
1596 | offset = n_refs * size; | |
1597 | break; | |
1598 | case POST_DEC: | |
1599 | offset = -n_refs * size; | |
1600 | break; | |
1601 | ||
1602 | default: | |
1603 | return addr; | |
1604 | } | |
ca7fd9cd | 1605 | |
39cec1ac | 1606 | if (offset) |
45183e03 | 1607 | addr = gen_rtx_PLUS (GET_MODE (addr), XEXP (addr, 0), |
c22cacf3 | 1608 | GEN_INT (offset)); |
39cec1ac MH |
1609 | else |
1610 | addr = XEXP (addr, 0); | |
45183e03 | 1611 | addr = canon_rtx (addr); |
39cec1ac MH |
1612 | |
1613 | return addr; | |
1614 | } | |
1615 | ||
9ae8ffe7 JL |
1616 | /* Return nonzero if X and Y (memory addresses) could reference the |
1617 | same location in memory. C is an offset accumulator. When | |
1618 | C is nonzero, we are testing aliases between X and Y + C. | |
1619 | XSIZE is the size in bytes of the X reference, | |
1620 | similarly YSIZE is the size in bytes for Y. | |
45183e03 | 1621 | Expect that canon_rtx has been already called for X and Y. |
9ae8ffe7 JL |
1622 | |
1623 | If XSIZE or YSIZE is zero, we do not know the amount of memory being | |
1624 | referenced (the reference was BLKmode), so make the most pessimistic | |
1625 | assumptions. | |
1626 | ||
c02f035f RH |
1627 | If XSIZE or YSIZE is negative, we may access memory outside the object |
1628 | being referenced as a side effect. This can happen when using AND to | |
1629 | align memory references, as is done on the Alpha. | |
1630 | ||
9ae8ffe7 | 1631 | Nice to notice that varying addresses cannot conflict with fp if no |
0211b6ab | 1632 | local variables had their addresses taken, but that's too hard now. */ |
9ae8ffe7 | 1633 | |
9ae8ffe7 | 1634 | static int |
4682ae04 | 1635 | memrefs_conflict_p (int xsize, rtx x, int ysize, rtx y, HOST_WIDE_INT c) |
9ae8ffe7 | 1636 | { |
eab5c70a BS |
1637 | if (GET_CODE (x) == VALUE) |
1638 | x = get_addr (x); | |
1639 | if (GET_CODE (y) == VALUE) | |
1640 | y = get_addr (y); | |
9ae8ffe7 JL |
1641 | if (GET_CODE (x) == HIGH) |
1642 | x = XEXP (x, 0); | |
1643 | else if (GET_CODE (x) == LO_SUM) | |
1644 | x = XEXP (x, 1); | |
1645 | else | |
45183e03 | 1646 | x = addr_side_effect_eval (x, xsize, 0); |
9ae8ffe7 JL |
1647 | if (GET_CODE (y) == HIGH) |
1648 | y = XEXP (y, 0); | |
1649 | else if (GET_CODE (y) == LO_SUM) | |
1650 | y = XEXP (y, 1); | |
1651 | else | |
45183e03 | 1652 | y = addr_side_effect_eval (y, ysize, 0); |
9ae8ffe7 JL |
1653 | |
1654 | if (rtx_equal_for_memref_p (x, y)) | |
1655 | { | |
c02f035f | 1656 | if (xsize <= 0 || ysize <= 0) |
9ae8ffe7 JL |
1657 | return 1; |
1658 | if (c >= 0 && xsize > c) | |
1659 | return 1; | |
1660 | if (c < 0 && ysize+c > 0) | |
1661 | return 1; | |
1662 | return 0; | |
1663 | } | |
1664 | ||
6e73e666 JC |
1665 | /* This code used to check for conflicts involving stack references and |
1666 | globals but the base address alias code now handles these cases. */ | |
9ae8ffe7 JL |
1667 | |
1668 | if (GET_CODE (x) == PLUS) | |
1669 | { | |
1670 | /* The fact that X is canonicalized means that this | |
1671 | PLUS rtx is canonicalized. */ | |
1672 | rtx x0 = XEXP (x, 0); | |
1673 | rtx x1 = XEXP (x, 1); | |
1674 | ||
1675 | if (GET_CODE (y) == PLUS) | |
1676 | { | |
1677 | /* The fact that Y is canonicalized means that this | |
1678 | PLUS rtx is canonicalized. */ | |
1679 | rtx y0 = XEXP (y, 0); | |
1680 | rtx y1 = XEXP (y, 1); | |
1681 | ||
1682 | if (rtx_equal_for_memref_p (x1, y1)) | |
1683 | return memrefs_conflict_p (xsize, x0, ysize, y0, c); | |
1684 | if (rtx_equal_for_memref_p (x0, y0)) | |
1685 | return memrefs_conflict_p (xsize, x1, ysize, y1, c); | |
1686 | if (GET_CODE (x1) == CONST_INT) | |
63be02db JM |
1687 | { |
1688 | if (GET_CODE (y1) == CONST_INT) | |
1689 | return memrefs_conflict_p (xsize, x0, ysize, y0, | |
1690 | c - INTVAL (x1) + INTVAL (y1)); | |
1691 | else | |
1692 | return memrefs_conflict_p (xsize, x0, ysize, y, | |
1693 | c - INTVAL (x1)); | |
1694 | } | |
9ae8ffe7 JL |
1695 | else if (GET_CODE (y1) == CONST_INT) |
1696 | return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1)); | |
1697 | ||
6e73e666 | 1698 | return 1; |
9ae8ffe7 JL |
1699 | } |
1700 | else if (GET_CODE (x1) == CONST_INT) | |
1701 | return memrefs_conflict_p (xsize, x0, ysize, y, c - INTVAL (x1)); | |
1702 | } | |
1703 | else if (GET_CODE (y) == PLUS) | |
1704 | { | |
1705 | /* The fact that Y is canonicalized means that this | |
1706 | PLUS rtx is canonicalized. */ | |
1707 | rtx y0 = XEXP (y, 0); | |
1708 | rtx y1 = XEXP (y, 1); | |
1709 | ||
1710 | if (GET_CODE (y1) == CONST_INT) | |
1711 | return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1)); | |
1712 | else | |
1713 | return 1; | |
1714 | } | |
1715 | ||
1716 | if (GET_CODE (x) == GET_CODE (y)) | |
1717 | switch (GET_CODE (x)) | |
1718 | { | |
1719 | case MULT: | |
1720 | { | |
1721 | /* Handle cases where we expect the second operands to be the | |
1722 | same, and check only whether the first operand would conflict | |
1723 | or not. */ | |
1724 | rtx x0, y0; | |
1725 | rtx x1 = canon_rtx (XEXP (x, 1)); | |
1726 | rtx y1 = canon_rtx (XEXP (y, 1)); | |
1727 | if (! rtx_equal_for_memref_p (x1, y1)) | |
1728 | return 1; | |
1729 | x0 = canon_rtx (XEXP (x, 0)); | |
1730 | y0 = canon_rtx (XEXP (y, 0)); | |
1731 | if (rtx_equal_for_memref_p (x0, y0)) | |
1732 | return (xsize == 0 || ysize == 0 | |
1733 | || (c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)); | |
1734 | ||
1735 | /* Can't properly adjust our sizes. */ | |
1736 | if (GET_CODE (x1) != CONST_INT) | |
1737 | return 1; | |
1738 | xsize /= INTVAL (x1); | |
1739 | ysize /= INTVAL (x1); | |
1740 | c /= INTVAL (x1); | |
1741 | return memrefs_conflict_p (xsize, x0, ysize, y0, c); | |
1742 | } | |
1d300e19 KG |
1743 | |
1744 | default: | |
1745 | break; | |
9ae8ffe7 JL |
1746 | } |
1747 | ||
1748 | /* Treat an access through an AND (e.g. a subword access on an Alpha) | |
ca7fd9cd | 1749 | as an access with indeterminate size. Assume that references |
56ee9281 RH |
1750 | besides AND are aligned, so if the size of the other reference is |
1751 | at least as large as the alignment, assume no other overlap. */ | |
9ae8ffe7 | 1752 | if (GET_CODE (x) == AND && GET_CODE (XEXP (x, 1)) == CONST_INT) |
56ee9281 | 1753 | { |
02e3377d | 1754 | if (GET_CODE (y) == AND || ysize < -INTVAL (XEXP (x, 1))) |
56ee9281 | 1755 | xsize = -1; |
45183e03 | 1756 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), ysize, y, c); |
56ee9281 | 1757 | } |
9ae8ffe7 | 1758 | if (GET_CODE (y) == AND && GET_CODE (XEXP (y, 1)) == CONST_INT) |
c02f035f | 1759 | { |
56ee9281 | 1760 | /* ??? If we are indexing far enough into the array/structure, we |
ca7fd9cd | 1761 | may yet be able to determine that we can not overlap. But we |
c02f035f | 1762 | also need to that we are far enough from the end not to overlap |
56ee9281 | 1763 | a following reference, so we do nothing with that for now. */ |
02e3377d | 1764 | if (GET_CODE (x) == AND || xsize < -INTVAL (XEXP (y, 1))) |
56ee9281 | 1765 | ysize = -1; |
45183e03 | 1766 | return memrefs_conflict_p (xsize, x, ysize, canon_rtx (XEXP (y, 0)), c); |
c02f035f | 1767 | } |
9ae8ffe7 JL |
1768 | |
1769 | if (CONSTANT_P (x)) | |
1770 | { | |
1771 | if (GET_CODE (x) == CONST_INT && GET_CODE (y) == CONST_INT) | |
1772 | { | |
1773 | c += (INTVAL (y) - INTVAL (x)); | |
c02f035f | 1774 | return (xsize <= 0 || ysize <= 0 |
9ae8ffe7 JL |
1775 | || (c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)); |
1776 | } | |
1777 | ||
1778 | if (GET_CODE (x) == CONST) | |
1779 | { | |
1780 | if (GET_CODE (y) == CONST) | |
1781 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), | |
1782 | ysize, canon_rtx (XEXP (y, 0)), c); | |
1783 | else | |
1784 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), | |
1785 | ysize, y, c); | |
1786 | } | |
1787 | if (GET_CODE (y) == CONST) | |
1788 | return memrefs_conflict_p (xsize, x, ysize, | |
1789 | canon_rtx (XEXP (y, 0)), c); | |
1790 | ||
1791 | if (CONSTANT_P (y)) | |
b949ea8b | 1792 | return (xsize <= 0 || ysize <= 0 |
c02f035f | 1793 | || (rtx_equal_for_memref_p (x, y) |
b949ea8b | 1794 | && ((c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)))); |
9ae8ffe7 JL |
1795 | |
1796 | return 1; | |
1797 | } | |
1798 | return 1; | |
1799 | } | |
1800 | ||
1801 | /* Functions to compute memory dependencies. | |
1802 | ||
1803 | Since we process the insns in execution order, we can build tables | |
1804 | to keep track of what registers are fixed (and not aliased), what registers | |
1805 | are varying in known ways, and what registers are varying in unknown | |
1806 | ways. | |
1807 | ||
1808 | If both memory references are volatile, then there must always be a | |
1809 | dependence between the two references, since their order can not be | |
1810 | changed. A volatile and non-volatile reference can be interchanged | |
ca7fd9cd | 1811 | though. |
9ae8ffe7 | 1812 | |
dc1618bc RK |
1813 | A MEM_IN_STRUCT reference at a non-AND varying address can never |
1814 | conflict with a non-MEM_IN_STRUCT reference at a fixed address. We | |
1815 | also must allow AND addresses, because they may generate accesses | |
1816 | outside the object being referenced. This is used to generate | |
1817 | aligned addresses from unaligned addresses, for instance, the alpha | |
1818 | storeqi_unaligned pattern. */ | |
9ae8ffe7 JL |
1819 | |
1820 | /* Read dependence: X is read after read in MEM takes place. There can | |
1821 | only be a dependence here if both reads are volatile. */ | |
1822 | ||
1823 | int | |
4f588890 | 1824 | read_dependence (const_rtx mem, const_rtx x) |
9ae8ffe7 JL |
1825 | { |
1826 | return MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem); | |
1827 | } | |
1828 | ||
c6df88cb MM |
1829 | /* Returns MEM1 if and only if MEM1 is a scalar at a fixed address and |
1830 | MEM2 is a reference to a structure at a varying address, or returns | |
1831 | MEM2 if vice versa. Otherwise, returns NULL_RTX. If a non-NULL | |
1832 | value is returned MEM1 and MEM2 can never alias. VARIES_P is used | |
1833 | to decide whether or not an address may vary; it should return | |
eab5c70a BS |
1834 | nonzero whenever variation is possible. |
1835 | MEM1_ADDR and MEM2_ADDR are the addresses of MEM1 and MEM2. */ | |
ca7fd9cd | 1836 | |
4f588890 KG |
1837 | static const_rtx |
1838 | fixed_scalar_and_varying_struct_p (const_rtx mem1, const_rtx mem2, rtx mem1_addr, | |
4682ae04 | 1839 | rtx mem2_addr, |
4f588890 | 1840 | bool (*varies_p) (const_rtx, bool)) |
ca7fd9cd | 1841 | { |
3e0abe15 GK |
1842 | if (! flag_strict_aliasing) |
1843 | return NULL_RTX; | |
1844 | ||
afa8f0fb AP |
1845 | if (MEM_ALIAS_SET (mem2) |
1846 | && MEM_SCALAR_P (mem1) && MEM_IN_STRUCT_P (mem2) | |
e38fe8e0 | 1847 | && !varies_p (mem1_addr, 1) && varies_p (mem2_addr, 1)) |
c6df88cb MM |
1848 | /* MEM1 is a scalar at a fixed address; MEM2 is a struct at a |
1849 | varying address. */ | |
1850 | return mem1; | |
1851 | ||
afa8f0fb AP |
1852 | if (MEM_ALIAS_SET (mem1) |
1853 | && MEM_IN_STRUCT_P (mem1) && MEM_SCALAR_P (mem2) | |
e38fe8e0 | 1854 | && varies_p (mem1_addr, 1) && !varies_p (mem2_addr, 1)) |
c6df88cb MM |
1855 | /* MEM2 is a scalar at a fixed address; MEM1 is a struct at a |
1856 | varying address. */ | |
1857 | return mem2; | |
1858 | ||
1859 | return NULL_RTX; | |
1860 | } | |
1861 | ||
1862 | /* Returns nonzero if something about the mode or address format MEM1 | |
1863 | indicates that it might well alias *anything*. */ | |
1864 | ||
2c72b78f | 1865 | static int |
4f588890 | 1866 | aliases_everything_p (const_rtx mem) |
c6df88cb | 1867 | { |
c6df88cb | 1868 | if (GET_CODE (XEXP (mem, 0)) == AND) |
35fd3193 | 1869 | /* If the address is an AND, it's very hard to know at what it is |
c6df88cb MM |
1870 | actually pointing. */ |
1871 | return 1; | |
ca7fd9cd | 1872 | |
c6df88cb MM |
1873 | return 0; |
1874 | } | |
1875 | ||
998d7deb RH |
1876 | /* Return true if we can determine that the fields referenced cannot |
1877 | overlap for any pair of objects. */ | |
1878 | ||
1879 | static bool | |
4f588890 | 1880 | nonoverlapping_component_refs_p (const_tree x, const_tree y) |
998d7deb | 1881 | { |
4f588890 | 1882 | const_tree fieldx, fieldy, typex, typey, orig_y; |
998d7deb RH |
1883 | |
1884 | do | |
1885 | { | |
1886 | /* The comparison has to be done at a common type, since we don't | |
d6a7951f | 1887 | know how the inheritance hierarchy works. */ |
998d7deb RH |
1888 | orig_y = y; |
1889 | do | |
1890 | { | |
1891 | fieldx = TREE_OPERAND (x, 1); | |
c05a0766 | 1892 | typex = TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (fieldx)); |
998d7deb RH |
1893 | |
1894 | y = orig_y; | |
1895 | do | |
1896 | { | |
1897 | fieldy = TREE_OPERAND (y, 1); | |
c05a0766 | 1898 | typey = TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (fieldy)); |
998d7deb RH |
1899 | |
1900 | if (typex == typey) | |
1901 | goto found; | |
1902 | ||
1903 | y = TREE_OPERAND (y, 0); | |
1904 | } | |
1905 | while (y && TREE_CODE (y) == COMPONENT_REF); | |
1906 | ||
1907 | x = TREE_OPERAND (x, 0); | |
1908 | } | |
1909 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
998d7deb | 1910 | /* Never found a common type. */ |
c05a0766 | 1911 | return false; |
998d7deb RH |
1912 | |
1913 | found: | |
1914 | /* If we're left with accessing different fields of a structure, | |
1915 | then no overlap. */ | |
1916 | if (TREE_CODE (typex) == RECORD_TYPE | |
1917 | && fieldx != fieldy) | |
1918 | return true; | |
1919 | ||
1920 | /* The comparison on the current field failed. If we're accessing | |
1921 | a very nested structure, look at the next outer level. */ | |
1922 | x = TREE_OPERAND (x, 0); | |
1923 | y = TREE_OPERAND (y, 0); | |
1924 | } | |
1925 | while (x && y | |
1926 | && TREE_CODE (x) == COMPONENT_REF | |
1927 | && TREE_CODE (y) == COMPONENT_REF); | |
ca7fd9cd | 1928 | |
998d7deb RH |
1929 | return false; |
1930 | } | |
1931 | ||
1932 | /* Look at the bottom of the COMPONENT_REF list for a DECL, and return it. */ | |
1933 | ||
1934 | static tree | |
4682ae04 | 1935 | decl_for_component_ref (tree x) |
998d7deb RH |
1936 | { |
1937 | do | |
1938 | { | |
1939 | x = TREE_OPERAND (x, 0); | |
1940 | } | |
1941 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
1942 | ||
1943 | return x && DECL_P (x) ? x : NULL_TREE; | |
1944 | } | |
1945 | ||
1946 | /* Walk up the COMPONENT_REF list and adjust OFFSET to compensate for the | |
1947 | offset of the field reference. */ | |
1948 | ||
1949 | static rtx | |
4682ae04 | 1950 | adjust_offset_for_component_ref (tree x, rtx offset) |
998d7deb RH |
1951 | { |
1952 | HOST_WIDE_INT ioffset; | |
1953 | ||
1954 | if (! offset) | |
1955 | return NULL_RTX; | |
1956 | ||
1957 | ioffset = INTVAL (offset); | |
ca7fd9cd | 1958 | do |
998d7deb | 1959 | { |
44de5aeb | 1960 | tree offset = component_ref_field_offset (x); |
998d7deb RH |
1961 | tree field = TREE_OPERAND (x, 1); |
1962 | ||
44de5aeb | 1963 | if (! host_integerp (offset, 1)) |
998d7deb | 1964 | return NULL_RTX; |
44de5aeb | 1965 | ioffset += (tree_low_cst (offset, 1) |
998d7deb RH |
1966 | + (tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1) |
1967 | / BITS_PER_UNIT)); | |
1968 | ||
1969 | x = TREE_OPERAND (x, 0); | |
1970 | } | |
1971 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
1972 | ||
1973 | return GEN_INT (ioffset); | |
1974 | } | |
1975 | ||
95bd1dd7 | 1976 | /* Return nonzero if we can determine the exprs corresponding to memrefs |
a4311dfe RK |
1977 | X and Y and they do not overlap. */ |
1978 | ||
2e4e39f6 | 1979 | int |
4f588890 | 1980 | nonoverlapping_memrefs_p (const_rtx x, const_rtx y) |
a4311dfe | 1981 | { |
998d7deb | 1982 | tree exprx = MEM_EXPR (x), expry = MEM_EXPR (y); |
a4311dfe RK |
1983 | rtx rtlx, rtly; |
1984 | rtx basex, basey; | |
998d7deb | 1985 | rtx moffsetx, moffsety; |
a4311dfe RK |
1986 | HOST_WIDE_INT offsetx = 0, offsety = 0, sizex, sizey, tem; |
1987 | ||
998d7deb RH |
1988 | /* Unless both have exprs, we can't tell anything. */ |
1989 | if (exprx == 0 || expry == 0) | |
1990 | return 0; | |
c22cacf3 | 1991 | |
998d7deb RH |
1992 | /* If both are field references, we may be able to determine something. */ |
1993 | if (TREE_CODE (exprx) == COMPONENT_REF | |
1994 | && TREE_CODE (expry) == COMPONENT_REF | |
1995 | && nonoverlapping_component_refs_p (exprx, expry)) | |
1996 | return 1; | |
1997 | ||
c22cacf3 | 1998 | |
998d7deb RH |
1999 | /* If the field reference test failed, look at the DECLs involved. */ |
2000 | moffsetx = MEM_OFFSET (x); | |
2001 | if (TREE_CODE (exprx) == COMPONENT_REF) | |
2002 | { | |
ea900239 DB |
2003 | if (TREE_CODE (expry) == VAR_DECL |
2004 | && POINTER_TYPE_P (TREE_TYPE (expry))) | |
2005 | { | |
2006 | tree field = TREE_OPERAND (exprx, 1); | |
2007 | tree fieldcontext = DECL_FIELD_CONTEXT (field); | |
2008 | if (ipa_type_escape_field_does_not_clobber_p (fieldcontext, | |
2009 | TREE_TYPE (field))) | |
c22cacf3 | 2010 | return 1; |
ea900239 DB |
2011 | } |
2012 | { | |
2013 | tree t = decl_for_component_ref (exprx); | |
2014 | if (! t) | |
2015 | return 0; | |
2016 | moffsetx = adjust_offset_for_component_ref (exprx, moffsetx); | |
2017 | exprx = t; | |
2018 | } | |
998d7deb | 2019 | } |
1b096a0a | 2020 | else if (INDIRECT_REF_P (exprx)) |
c67a1cf6 RH |
2021 | { |
2022 | exprx = TREE_OPERAND (exprx, 0); | |
2023 | if (flag_argument_noalias < 2 | |
2024 | || TREE_CODE (exprx) != PARM_DECL) | |
2025 | return 0; | |
2026 | } | |
2027 | ||
998d7deb RH |
2028 | moffsety = MEM_OFFSET (y); |
2029 | if (TREE_CODE (expry) == COMPONENT_REF) | |
2030 | { | |
ea900239 DB |
2031 | if (TREE_CODE (exprx) == VAR_DECL |
2032 | && POINTER_TYPE_P (TREE_TYPE (exprx))) | |
2033 | { | |
2034 | tree field = TREE_OPERAND (expry, 1); | |
2035 | tree fieldcontext = DECL_FIELD_CONTEXT (field); | |
2036 | if (ipa_type_escape_field_does_not_clobber_p (fieldcontext, | |
2037 | TREE_TYPE (field))) | |
c22cacf3 | 2038 | return 1; |
ea900239 DB |
2039 | } |
2040 | { | |
2041 | tree t = decl_for_component_ref (expry); | |
2042 | if (! t) | |
2043 | return 0; | |
2044 | moffsety = adjust_offset_for_component_ref (expry, moffsety); | |
2045 | expry = t; | |
2046 | } | |
998d7deb | 2047 | } |
1b096a0a | 2048 | else if (INDIRECT_REF_P (expry)) |
c67a1cf6 RH |
2049 | { |
2050 | expry = TREE_OPERAND (expry, 0); | |
2051 | if (flag_argument_noalias < 2 | |
2052 | || TREE_CODE (expry) != PARM_DECL) | |
2053 | return 0; | |
2054 | } | |
998d7deb RH |
2055 | |
2056 | if (! DECL_P (exprx) || ! DECL_P (expry)) | |
a4311dfe RK |
2057 | return 0; |
2058 | ||
998d7deb RH |
2059 | rtlx = DECL_RTL (exprx); |
2060 | rtly = DECL_RTL (expry); | |
a4311dfe | 2061 | |
1edcd60b RK |
2062 | /* If either RTL is not a MEM, it must be a REG or CONCAT, meaning they |
2063 | can't overlap unless they are the same because we never reuse that part | |
2064 | of the stack frame used for locals for spilled pseudos. */ | |
3c0cb5de | 2065 | if ((!MEM_P (rtlx) || !MEM_P (rtly)) |
1edcd60b | 2066 | && ! rtx_equal_p (rtlx, rtly)) |
a4311dfe RK |
2067 | return 1; |
2068 | ||
2069 | /* Get the base and offsets of both decls. If either is a register, we | |
2070 | know both are and are the same, so use that as the base. The only | |
2071 | we can avoid overlap is if we can deduce that they are nonoverlapping | |
2072 | pieces of that decl, which is very rare. */ | |
3c0cb5de | 2073 | basex = MEM_P (rtlx) ? XEXP (rtlx, 0) : rtlx; |
a4311dfe RK |
2074 | if (GET_CODE (basex) == PLUS && GET_CODE (XEXP (basex, 1)) == CONST_INT) |
2075 | offsetx = INTVAL (XEXP (basex, 1)), basex = XEXP (basex, 0); | |
2076 | ||
3c0cb5de | 2077 | basey = MEM_P (rtly) ? XEXP (rtly, 0) : rtly; |
a4311dfe RK |
2078 | if (GET_CODE (basey) == PLUS && GET_CODE (XEXP (basey, 1)) == CONST_INT) |
2079 | offsety = INTVAL (XEXP (basey, 1)), basey = XEXP (basey, 0); | |
2080 | ||
d746694a | 2081 | /* If the bases are different, we know they do not overlap if both |
ca7fd9cd | 2082 | are constants or if one is a constant and the other a pointer into the |
d746694a RK |
2083 | stack frame. Otherwise a different base means we can't tell if they |
2084 | overlap or not. */ | |
2085 | if (! rtx_equal_p (basex, basey)) | |
ca7fd9cd KH |
2086 | return ((CONSTANT_P (basex) && CONSTANT_P (basey)) |
2087 | || (CONSTANT_P (basex) && REG_P (basey) | |
2088 | && REGNO_PTR_FRAME_P (REGNO (basey))) | |
2089 | || (CONSTANT_P (basey) && REG_P (basex) | |
2090 | && REGNO_PTR_FRAME_P (REGNO (basex)))); | |
a4311dfe | 2091 | |
3c0cb5de | 2092 | sizex = (!MEM_P (rtlx) ? (int) GET_MODE_SIZE (GET_MODE (rtlx)) |
a4311dfe RK |
2093 | : MEM_SIZE (rtlx) ? INTVAL (MEM_SIZE (rtlx)) |
2094 | : -1); | |
3c0cb5de | 2095 | sizey = (!MEM_P (rtly) ? (int) GET_MODE_SIZE (GET_MODE (rtly)) |
a4311dfe RK |
2096 | : MEM_SIZE (rtly) ? INTVAL (MEM_SIZE (rtly)) : |
2097 | -1); | |
2098 | ||
0af5bc3e RK |
2099 | /* If we have an offset for either memref, it can update the values computed |
2100 | above. */ | |
998d7deb RH |
2101 | if (moffsetx) |
2102 | offsetx += INTVAL (moffsetx), sizex -= INTVAL (moffsetx); | |
2103 | if (moffsety) | |
2104 | offsety += INTVAL (moffsety), sizey -= INTVAL (moffsety); | |
a4311dfe | 2105 | |
0af5bc3e | 2106 | /* If a memref has both a size and an offset, we can use the smaller size. |
efc981bb | 2107 | We can't do this if the offset isn't known because we must view this |
0af5bc3e | 2108 | memref as being anywhere inside the DECL's MEM. */ |
998d7deb | 2109 | if (MEM_SIZE (x) && moffsetx) |
a4311dfe | 2110 | sizex = INTVAL (MEM_SIZE (x)); |
998d7deb | 2111 | if (MEM_SIZE (y) && moffsety) |
a4311dfe RK |
2112 | sizey = INTVAL (MEM_SIZE (y)); |
2113 | ||
2114 | /* Put the values of the memref with the lower offset in X's values. */ | |
2115 | if (offsetx > offsety) | |
2116 | { | |
2117 | tem = offsetx, offsetx = offsety, offsety = tem; | |
2118 | tem = sizex, sizex = sizey, sizey = tem; | |
2119 | } | |
2120 | ||
2121 | /* If we don't know the size of the lower-offset value, we can't tell | |
2122 | if they conflict. Otherwise, we do the test. */ | |
a6f7c915 | 2123 | return sizex >= 0 && offsety >= offsetx + sizex; |
a4311dfe RK |
2124 | } |
2125 | ||
9ae8ffe7 JL |
2126 | /* True dependence: X is read after store in MEM takes place. */ |
2127 | ||
2128 | int | |
4f588890 KG |
2129 | true_dependence (const_rtx mem, enum machine_mode mem_mode, const_rtx x, |
2130 | bool (*varies) (const_rtx, bool)) | |
9ae8ffe7 | 2131 | { |
b3694847 | 2132 | rtx x_addr, mem_addr; |
49982682 | 2133 | rtx base; |
9ae8ffe7 JL |
2134 | |
2135 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) | |
2136 | return 1; | |
2137 | ||
c4484b8f | 2138 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
ac3768f6 | 2139 | This is used in epilogue deallocation functions, and in cselib. */ |
c4484b8f RH |
2140 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) |
2141 | return 1; | |
2142 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
2143 | return 1; | |
9cd9e512 RH |
2144 | if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER |
2145 | || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER) | |
2146 | return 1; | |
c4484b8f | 2147 | |
41472af8 MM |
2148 | if (DIFFERENT_ALIAS_SETS_P (x, mem)) |
2149 | return 0; | |
2150 | ||
389fdba0 RH |
2151 | /* Read-only memory is by definition never modified, and therefore can't |
2152 | conflict with anything. We don't expect to find read-only set on MEM, | |
41806d92 | 2153 | but stupid user tricks can produce them, so don't die. */ |
389fdba0 | 2154 | if (MEM_READONLY_P (x)) |
9ae8ffe7 JL |
2155 | return 0; |
2156 | ||
a4311dfe RK |
2157 | if (nonoverlapping_memrefs_p (mem, x)) |
2158 | return 0; | |
2159 | ||
56ee9281 RH |
2160 | if (mem_mode == VOIDmode) |
2161 | mem_mode = GET_MODE (mem); | |
2162 | ||
eab5c70a BS |
2163 | x_addr = get_addr (XEXP (x, 0)); |
2164 | mem_addr = get_addr (XEXP (mem, 0)); | |
2165 | ||
55efb413 JW |
2166 | base = find_base_term (x_addr); |
2167 | if (base && (GET_CODE (base) == LABEL_REF | |
2168 | || (GET_CODE (base) == SYMBOL_REF | |
2169 | && CONSTANT_POOL_ADDRESS_P (base)))) | |
2170 | return 0; | |
2171 | ||
eab5c70a | 2172 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), mem_mode)) |
1c72c7f6 JC |
2173 | return 0; |
2174 | ||
eab5c70a BS |
2175 | x_addr = canon_rtx (x_addr); |
2176 | mem_addr = canon_rtx (mem_addr); | |
6e73e666 | 2177 | |
0211b6ab JW |
2178 | if (! memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr, |
2179 | SIZE_FOR_MODE (x), x_addr, 0)) | |
2180 | return 0; | |
2181 | ||
c6df88cb | 2182 | if (aliases_everything_p (x)) |
0211b6ab JW |
2183 | return 1; |
2184 | ||
f5143c46 | 2185 | /* We cannot use aliases_everything_p to test MEM, since we must look |
c6df88cb MM |
2186 | at MEM_MODE, rather than GET_MODE (MEM). */ |
2187 | if (mem_mode == QImode || GET_CODE (mem_addr) == AND) | |
a13d4ebf AM |
2188 | return 1; |
2189 | ||
2190 | /* In true_dependence we also allow BLKmode to alias anything. Why | |
2191 | don't we do this in anti_dependence and output_dependence? */ | |
2192 | if (mem_mode == BLKmode || GET_MODE (x) == BLKmode) | |
2193 | return 1; | |
2194 | ||
2195 | return ! fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, | |
2196 | varies); | |
2197 | } | |
2198 | ||
2199 | /* Canonical true dependence: X is read after store in MEM takes place. | |
ca7fd9cd KH |
2200 | Variant of true_dependence which assumes MEM has already been |
2201 | canonicalized (hence we no longer do that here). | |
2202 | The mem_addr argument has been added, since true_dependence computed | |
a13d4ebf AM |
2203 | this value prior to canonicalizing. */ |
2204 | ||
2205 | int | |
4f588890 KG |
2206 | canon_true_dependence (const_rtx mem, enum machine_mode mem_mode, rtx mem_addr, |
2207 | const_rtx x, bool (*varies) (const_rtx, bool)) | |
a13d4ebf | 2208 | { |
b3694847 | 2209 | rtx x_addr; |
a13d4ebf AM |
2210 | |
2211 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) | |
2212 | return 1; | |
2213 | ||
0fe854a7 RH |
2214 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
2215 | This is used in epilogue deallocation functions. */ | |
2216 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) | |
2217 | return 1; | |
2218 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
2219 | return 1; | |
9cd9e512 RH |
2220 | if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER |
2221 | || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER) | |
2222 | return 1; | |
0fe854a7 | 2223 | |
a13d4ebf AM |
2224 | if (DIFFERENT_ALIAS_SETS_P (x, mem)) |
2225 | return 0; | |
2226 | ||
389fdba0 RH |
2227 | /* Read-only memory is by definition never modified, and therefore can't |
2228 | conflict with anything. We don't expect to find read-only set on MEM, | |
41806d92 | 2229 | but stupid user tricks can produce them, so don't die. */ |
389fdba0 | 2230 | if (MEM_READONLY_P (x)) |
a13d4ebf AM |
2231 | return 0; |
2232 | ||
a4311dfe RK |
2233 | if (nonoverlapping_memrefs_p (x, mem)) |
2234 | return 0; | |
2235 | ||
a13d4ebf AM |
2236 | x_addr = get_addr (XEXP (x, 0)); |
2237 | ||
2238 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), mem_mode)) | |
2239 | return 0; | |
2240 | ||
2241 | x_addr = canon_rtx (x_addr); | |
2242 | if (! memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr, | |
2243 | SIZE_FOR_MODE (x), x_addr, 0)) | |
2244 | return 0; | |
2245 | ||
2246 | if (aliases_everything_p (x)) | |
2247 | return 1; | |
2248 | ||
f5143c46 | 2249 | /* We cannot use aliases_everything_p to test MEM, since we must look |
a13d4ebf AM |
2250 | at MEM_MODE, rather than GET_MODE (MEM). */ |
2251 | if (mem_mode == QImode || GET_CODE (mem_addr) == AND) | |
c6df88cb | 2252 | return 1; |
0211b6ab | 2253 | |
c6df88cb MM |
2254 | /* In true_dependence we also allow BLKmode to alias anything. Why |
2255 | don't we do this in anti_dependence and output_dependence? */ | |
2256 | if (mem_mode == BLKmode || GET_MODE (x) == BLKmode) | |
2257 | return 1; | |
0211b6ab | 2258 | |
eab5c70a BS |
2259 | return ! fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, |
2260 | varies); | |
9ae8ffe7 JL |
2261 | } |
2262 | ||
da7d8304 | 2263 | /* Returns nonzero if a write to X might alias a previous read from |
389fdba0 | 2264 | (or, if WRITEP is nonzero, a write to) MEM. */ |
9ae8ffe7 | 2265 | |
2c72b78f | 2266 | static int |
4f588890 | 2267 | write_dependence_p (const_rtx mem, const_rtx x, int writep) |
9ae8ffe7 | 2268 | { |
6e73e666 | 2269 | rtx x_addr, mem_addr; |
4f588890 | 2270 | const_rtx fixed_scalar; |
49982682 | 2271 | rtx base; |
6e73e666 | 2272 | |
9ae8ffe7 JL |
2273 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) |
2274 | return 1; | |
2275 | ||
c4484b8f RH |
2276 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
2277 | This is used in epilogue deallocation functions. */ | |
2278 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) | |
2279 | return 1; | |
2280 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
2281 | return 1; | |
9cd9e512 RH |
2282 | if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER |
2283 | || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER) | |
2284 | return 1; | |
c4484b8f | 2285 | |
eab5c70a BS |
2286 | if (DIFFERENT_ALIAS_SETS_P (x, mem)) |
2287 | return 0; | |
2288 | ||
389fdba0 RH |
2289 | /* A read from read-only memory can't conflict with read-write memory. */ |
2290 | if (!writep && MEM_READONLY_P (mem)) | |
2291 | return 0; | |
55efb413 | 2292 | |
a4311dfe RK |
2293 | if (nonoverlapping_memrefs_p (x, mem)) |
2294 | return 0; | |
2295 | ||
55efb413 JW |
2296 | x_addr = get_addr (XEXP (x, 0)); |
2297 | mem_addr = get_addr (XEXP (mem, 0)); | |
2298 | ||
49982682 JW |
2299 | if (! writep) |
2300 | { | |
55efb413 | 2301 | base = find_base_term (mem_addr); |
49982682 JW |
2302 | if (base && (GET_CODE (base) == LABEL_REF |
2303 | || (GET_CODE (base) == SYMBOL_REF | |
2304 | && CONSTANT_POOL_ADDRESS_P (base)))) | |
2305 | return 0; | |
2306 | } | |
2307 | ||
eab5c70a BS |
2308 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), |
2309 | GET_MODE (mem))) | |
41472af8 MM |
2310 | return 0; |
2311 | ||
eab5c70a BS |
2312 | x_addr = canon_rtx (x_addr); |
2313 | mem_addr = canon_rtx (mem_addr); | |
6e73e666 | 2314 | |
c6df88cb MM |
2315 | if (!memrefs_conflict_p (SIZE_FOR_MODE (mem), mem_addr, |
2316 | SIZE_FOR_MODE (x), x_addr, 0)) | |
2317 | return 0; | |
2318 | ||
ca7fd9cd | 2319 | fixed_scalar |
eab5c70a BS |
2320 | = fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, |
2321 | rtx_addr_varies_p); | |
2322 | ||
c6df88cb MM |
2323 | return (!(fixed_scalar == mem && !aliases_everything_p (x)) |
2324 | && !(fixed_scalar == x && !aliases_everything_p (mem))); | |
2325 | } | |
2326 | ||
2327 | /* Anti dependence: X is written after read in MEM takes place. */ | |
2328 | ||
2329 | int | |
4f588890 | 2330 | anti_dependence (const_rtx mem, const_rtx x) |
c6df88cb | 2331 | { |
389fdba0 | 2332 | return write_dependence_p (mem, x, /*writep=*/0); |
9ae8ffe7 JL |
2333 | } |
2334 | ||
2335 | /* Output dependence: X is written after store in MEM takes place. */ | |
2336 | ||
2337 | int | |
4f588890 | 2338 | output_dependence (const_rtx mem, const_rtx x) |
9ae8ffe7 | 2339 | { |
389fdba0 | 2340 | return write_dependence_p (mem, x, /*writep=*/1); |
9ae8ffe7 | 2341 | } |
c14b9960 | 2342 | \f |
6e73e666 | 2343 | |
6e73e666 | 2344 | void |
b5deb7b6 | 2345 | init_alias_target (void) |
6e73e666 | 2346 | { |
b3694847 | 2347 | int i; |
6e73e666 | 2348 | |
b5deb7b6 SL |
2349 | memset (static_reg_base_value, 0, sizeof static_reg_base_value); |
2350 | ||
6e73e666 JC |
2351 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) |
2352 | /* Check whether this register can hold an incoming pointer | |
2353 | argument. FUNCTION_ARG_REGNO_P tests outgoing register | |
ec5c56db | 2354 | numbers, so translate if necessary due to register windows. */ |
6e73e666 JC |
2355 | if (FUNCTION_ARG_REGNO_P (OUTGOING_REGNO (i)) |
2356 | && HARD_REGNO_MODE_OK (i, Pmode)) | |
bf1660a6 JL |
2357 | static_reg_base_value[i] |
2358 | = gen_rtx_ADDRESS (VOIDmode, gen_rtx_REG (Pmode, i)); | |
2359 | ||
bf1660a6 JL |
2360 | static_reg_base_value[STACK_POINTER_REGNUM] |
2361 | = gen_rtx_ADDRESS (Pmode, stack_pointer_rtx); | |
2362 | static_reg_base_value[ARG_POINTER_REGNUM] | |
2363 | = gen_rtx_ADDRESS (Pmode, arg_pointer_rtx); | |
2364 | static_reg_base_value[FRAME_POINTER_REGNUM] | |
2365 | = gen_rtx_ADDRESS (Pmode, frame_pointer_rtx); | |
2366 | #if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM | |
2367 | static_reg_base_value[HARD_FRAME_POINTER_REGNUM] | |
2368 | = gen_rtx_ADDRESS (Pmode, hard_frame_pointer_rtx); | |
2369 | #endif | |
2370 | } | |
2371 | ||
7b52eede JH |
2372 | /* Set MEMORY_MODIFIED when X modifies DATA (that is assumed |
2373 | to be memory reference. */ | |
2374 | static bool memory_modified; | |
2375 | static void | |
aa317c97 | 2376 | memory_modified_1 (rtx x, const_rtx pat ATTRIBUTE_UNUSED, void *data) |
7b52eede | 2377 | { |
3c0cb5de | 2378 | if (MEM_P (x)) |
7b52eede | 2379 | { |
9678086d | 2380 | if (anti_dependence (x, (const_rtx)data) || output_dependence (x, (const_rtx)data)) |
7b52eede JH |
2381 | memory_modified = true; |
2382 | } | |
2383 | } | |
2384 | ||
2385 | ||
2386 | /* Return true when INSN possibly modify memory contents of MEM | |
454ff5cb | 2387 | (i.e. address can be modified). */ |
7b52eede | 2388 | bool |
9678086d | 2389 | memory_modified_in_insn_p (const_rtx mem, const_rtx insn) |
7b52eede JH |
2390 | { |
2391 | if (!INSN_P (insn)) | |
2392 | return false; | |
2393 | memory_modified = false; | |
aa317c97 | 2394 | note_stores (PATTERN (insn), memory_modified_1, CONST_CAST_RTX(mem)); |
7b52eede JH |
2395 | return memory_modified; |
2396 | } | |
2397 | ||
c13e8210 MM |
2398 | /* Initialize the aliasing machinery. Initialize the REG_KNOWN_VALUE |
2399 | array. */ | |
2400 | ||
9ae8ffe7 | 2401 | void |
4682ae04 | 2402 | init_alias_analysis (void) |
9ae8ffe7 | 2403 | { |
c582d54a | 2404 | unsigned int maxreg = max_reg_num (); |
ea64ef27 | 2405 | int changed, pass; |
b3694847 SS |
2406 | int i; |
2407 | unsigned int ui; | |
2408 | rtx insn; | |
9ae8ffe7 | 2409 | |
0d446150 JH |
2410 | timevar_push (TV_ALIAS_ANALYSIS); |
2411 | ||
bb1acb3e RH |
2412 | reg_known_value_size = maxreg - FIRST_PSEUDO_REGISTER; |
2413 | reg_known_value = ggc_calloc (reg_known_value_size, sizeof (rtx)); | |
2414 | reg_known_equiv_p = xcalloc (reg_known_value_size, sizeof (bool)); | |
9ae8ffe7 | 2415 | |
08c79682 | 2416 | /* If we have memory allocated from the previous run, use it. */ |
c582d54a | 2417 | if (old_reg_base_value) |
08c79682 KH |
2418 | reg_base_value = old_reg_base_value; |
2419 | ||
2420 | if (reg_base_value) | |
2421 | VEC_truncate (rtx, reg_base_value, 0); | |
2422 | ||
a590ac65 | 2423 | VEC_safe_grow_cleared (rtx, gc, reg_base_value, maxreg); |
ac606739 | 2424 | |
5ed6ace5 MD |
2425 | new_reg_base_value = XNEWVEC (rtx, maxreg); |
2426 | reg_seen = XNEWVEC (char, maxreg); | |
ec907dd8 JL |
2427 | |
2428 | /* The basic idea is that each pass through this loop will use the | |
2429 | "constant" information from the previous pass to propagate alias | |
2430 | information through another level of assignments. | |
2431 | ||
2432 | This could get expensive if the assignment chains are long. Maybe | |
2433 | we should throttle the number of iterations, possibly based on | |
6e73e666 | 2434 | the optimization level or flag_expensive_optimizations. |
ec907dd8 JL |
2435 | |
2436 | We could propagate more information in the first pass by making use | |
6fb5fa3c | 2437 | of DF_REG_DEF_COUNT to determine immediately that the alias information |
ea64ef27 JL |
2438 | for a pseudo is "constant". |
2439 | ||
2440 | A program with an uninitialized variable can cause an infinite loop | |
2441 | here. Instead of doing a full dataflow analysis to detect such problems | |
2442 | we just cap the number of iterations for the loop. | |
2443 | ||
2444 | The state of the arrays for the set chain in question does not matter | |
2445 | since the program has undefined behavior. */ | |
6e73e666 | 2446 | |
ea64ef27 | 2447 | pass = 0; |
6e73e666 | 2448 | do |
ec907dd8 JL |
2449 | { |
2450 | /* Assume nothing will change this iteration of the loop. */ | |
2451 | changed = 0; | |
2452 | ||
ec907dd8 JL |
2453 | /* We want to assign the same IDs each iteration of this loop, so |
2454 | start counting from zero each iteration of the loop. */ | |
2455 | unique_id = 0; | |
2456 | ||
f5143c46 | 2457 | /* We're at the start of the function each iteration through the |
ec907dd8 | 2458 | loop, so we're copying arguments. */ |
83bbd9b6 | 2459 | copying_arguments = true; |
9ae8ffe7 | 2460 | |
6e73e666 | 2461 | /* Wipe the potential alias information clean for this pass. */ |
c582d54a | 2462 | memset (new_reg_base_value, 0, maxreg * sizeof (rtx)); |
8072f69c | 2463 | |
6e73e666 | 2464 | /* Wipe the reg_seen array clean. */ |
c582d54a | 2465 | memset (reg_seen, 0, maxreg); |
9ae8ffe7 | 2466 | |
6e73e666 JC |
2467 | /* Mark all hard registers which may contain an address. |
2468 | The stack, frame and argument pointers may contain an address. | |
2469 | An argument register which can hold a Pmode value may contain | |
2470 | an address even if it is not in BASE_REGS. | |
8072f69c | 2471 | |
6e73e666 JC |
2472 | The address expression is VOIDmode for an argument and |
2473 | Pmode for other registers. */ | |
2474 | ||
7f243674 JL |
2475 | memcpy (new_reg_base_value, static_reg_base_value, |
2476 | FIRST_PSEUDO_REGISTER * sizeof (rtx)); | |
6e73e666 | 2477 | |
ec907dd8 JL |
2478 | /* Walk the insns adding values to the new_reg_base_value array. */ |
2479 | for (insn = get_insns (); insn; insn = NEXT_INSN (insn)) | |
9ae8ffe7 | 2480 | { |
2c3c49de | 2481 | if (INSN_P (insn)) |
ec907dd8 | 2482 | { |
6e73e666 | 2483 | rtx note, set; |
efc9bd41 RK |
2484 | |
2485 | #if defined (HAVE_prologue) || defined (HAVE_epilogue) | |
f5143c46 | 2486 | /* The prologue/epilogue insns are not threaded onto the |
657959ca JL |
2487 | insn chain until after reload has completed. Thus, |
2488 | there is no sense wasting time checking if INSN is in | |
2489 | the prologue/epilogue until after reload has completed. */ | |
2490 | if (reload_completed | |
2491 | && prologue_epilogue_contains (insn)) | |
efc9bd41 RK |
2492 | continue; |
2493 | #endif | |
2494 | ||
ec907dd8 | 2495 | /* If this insn has a noalias note, process it, Otherwise, |
c22cacf3 MS |
2496 | scan for sets. A simple set will have no side effects |
2497 | which could change the base value of any other register. */ | |
6e73e666 | 2498 | |
ec907dd8 | 2499 | if (GET_CODE (PATTERN (insn)) == SET |
efc9bd41 RK |
2500 | && REG_NOTES (insn) != 0 |
2501 | && find_reg_note (insn, REG_NOALIAS, NULL_RTX)) | |
84832317 | 2502 | record_set (SET_DEST (PATTERN (insn)), NULL_RTX, NULL); |
ec907dd8 | 2503 | else |
84832317 | 2504 | note_stores (PATTERN (insn), record_set, NULL); |
6e73e666 JC |
2505 | |
2506 | set = single_set (insn); | |
2507 | ||
2508 | if (set != 0 | |
f8cfc6aa | 2509 | && REG_P (SET_DEST (set)) |
fb6754f0 | 2510 | && REGNO (SET_DEST (set)) >= FIRST_PSEUDO_REGISTER) |
6e73e666 | 2511 | { |
fb6754f0 | 2512 | unsigned int regno = REGNO (SET_DEST (set)); |
713f41f9 | 2513 | rtx src = SET_SRC (set); |
bb1acb3e | 2514 | rtx t; |
713f41f9 | 2515 | |
a31830a7 SB |
2516 | note = find_reg_equal_equiv_note (insn); |
2517 | if (note && REG_NOTE_KIND (note) == REG_EQUAL | |
6fb5fa3c | 2518 | && DF_REG_DEF_COUNT (regno) != 1) |
a31830a7 SB |
2519 | note = NULL_RTX; |
2520 | ||
2521 | if (note != NULL_RTX | |
713f41f9 | 2522 | && GET_CODE (XEXP (note, 0)) != EXPR_LIST |
bb2cf916 | 2523 | && ! rtx_varies_p (XEXP (note, 0), 1) |
bb1acb3e RH |
2524 | && ! reg_overlap_mentioned_p (SET_DEST (set), |
2525 | XEXP (note, 0))) | |
713f41f9 | 2526 | { |
bb1acb3e RH |
2527 | set_reg_known_value (regno, XEXP (note, 0)); |
2528 | set_reg_known_equiv_p (regno, | |
2529 | REG_NOTE_KIND (note) == REG_EQUIV); | |
713f41f9 | 2530 | } |
6fb5fa3c | 2531 | else if (DF_REG_DEF_COUNT (regno) == 1 |
713f41f9 | 2532 | && GET_CODE (src) == PLUS |
f8cfc6aa | 2533 | && REG_P (XEXP (src, 0)) |
bb1acb3e | 2534 | && (t = get_reg_known_value (REGNO (XEXP (src, 0)))) |
713f41f9 BS |
2535 | && GET_CODE (XEXP (src, 1)) == CONST_INT) |
2536 | { | |
bb1acb3e RH |
2537 | t = plus_constant (t, INTVAL (XEXP (src, 1))); |
2538 | set_reg_known_value (regno, t); | |
2539 | set_reg_known_equiv_p (regno, 0); | |
713f41f9 | 2540 | } |
6fb5fa3c | 2541 | else if (DF_REG_DEF_COUNT (regno) == 1 |
713f41f9 BS |
2542 | && ! rtx_varies_p (src, 1)) |
2543 | { | |
bb1acb3e RH |
2544 | set_reg_known_value (regno, src); |
2545 | set_reg_known_equiv_p (regno, 0); | |
713f41f9 | 2546 | } |
6e73e666 | 2547 | } |
ec907dd8 | 2548 | } |
4b4bf941 | 2549 | else if (NOTE_P (insn) |
a38e7aa5 | 2550 | && NOTE_KIND (insn) == NOTE_INSN_FUNCTION_BEG) |
83bbd9b6 | 2551 | copying_arguments = false; |
6e73e666 | 2552 | } |
ec907dd8 | 2553 | |
6e73e666 | 2554 | /* Now propagate values from new_reg_base_value to reg_base_value. */ |
62e5bf5d | 2555 | gcc_assert (maxreg == (unsigned int) max_reg_num ()); |
c22cacf3 | 2556 | |
c582d54a | 2557 | for (ui = 0; ui < maxreg; ui++) |
6e73e666 | 2558 | { |
e51712db | 2559 | if (new_reg_base_value[ui] |
08c79682 | 2560 | && new_reg_base_value[ui] != VEC_index (rtx, reg_base_value, ui) |
c582d54a | 2561 | && ! rtx_equal_p (new_reg_base_value[ui], |
08c79682 | 2562 | VEC_index (rtx, reg_base_value, ui))) |
ec907dd8 | 2563 | { |
08c79682 | 2564 | VEC_replace (rtx, reg_base_value, ui, new_reg_base_value[ui]); |
6e73e666 | 2565 | changed = 1; |
ec907dd8 | 2566 | } |
9ae8ffe7 | 2567 | } |
9ae8ffe7 | 2568 | } |
6e73e666 | 2569 | while (changed && ++pass < MAX_ALIAS_LOOP_PASSES); |
9ae8ffe7 JL |
2570 | |
2571 | /* Fill in the remaining entries. */ | |
bb1acb3e | 2572 | for (i = 0; i < (int)reg_known_value_size; i++) |
9ae8ffe7 | 2573 | if (reg_known_value[i] == 0) |
bb1acb3e | 2574 | reg_known_value[i] = regno_reg_rtx[i + FIRST_PSEUDO_REGISTER]; |
9ae8ffe7 | 2575 | |
e05e2395 MM |
2576 | /* Clean up. */ |
2577 | free (new_reg_base_value); | |
ec907dd8 | 2578 | new_reg_base_value = 0; |
e05e2395 | 2579 | free (reg_seen); |
9ae8ffe7 | 2580 | reg_seen = 0; |
0d446150 | 2581 | timevar_pop (TV_ALIAS_ANALYSIS); |
9ae8ffe7 JL |
2582 | } |
2583 | ||
2584 | void | |
4682ae04 | 2585 | end_alias_analysis (void) |
9ae8ffe7 | 2586 | { |
c582d54a | 2587 | old_reg_base_value = reg_base_value; |
bb1acb3e | 2588 | ggc_free (reg_known_value); |
9ae8ffe7 | 2589 | reg_known_value = 0; |
ac606739 | 2590 | reg_known_value_size = 0; |
bb1acb3e | 2591 | free (reg_known_equiv_p); |
e05e2395 | 2592 | reg_known_equiv_p = 0; |
9ae8ffe7 | 2593 | } |
e2500fed GK |
2594 | |
2595 | #include "gt-alias.h" |