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ea0cb7ae | 1 | /* Alias analysis for GNU C |
25763d80 | 2 | Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002 Free Software Foundation, Inc. |
ea0cb7ae | 3 | Contributed by John Carr (jfc@mit.edu). |
4 | ||
f12b58b3 | 5 | This file is part of GCC. |
ea0cb7ae | 6 | |
f12b58b3 | 7 | GCC is free software; you can redistribute it and/or modify it under |
8 | the terms of the GNU General Public License as published by the Free | |
9 | Software Foundation; either version 2, or (at your option) any later | |
10 | version. | |
ea0cb7ae | 11 | |
f12b58b3 | 12 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY |
13 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
14 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
15 | for more details. | |
ea0cb7ae | 16 | |
17 | You should have received a copy of the GNU General Public License | |
f12b58b3 | 18 | along with GCC; see the file COPYING. If not, write to the Free |
19 | Software Foundation, 59 Temple Place - Suite 330, Boston, MA | |
20 | 02111-1307, USA. */ | |
ea0cb7ae | 21 | |
22 | #include "config.h" | |
405711de | 23 | #include "system.h" |
805e22b2 | 24 | #include "coretypes.h" |
25 | #include "tm.h" | |
ea0cb7ae | 26 | #include "rtl.h" |
142131ed | 27 | #include "tree.h" |
7953c610 | 28 | #include "tm_p.h" |
0a893c29 | 29 | #include "function.h" |
ea0cb7ae | 30 | #include "expr.h" |
31 | #include "regs.h" | |
32 | #include "hard-reg-set.h" | |
080f162d | 33 | #include "basic-block.h" |
ea0cb7ae | 34 | #include "flags.h" |
a068b2a9 | 35 | #include "output.h" |
ce1fd7fc | 36 | #include "toplev.h" |
1617c276 | 37 | #include "cselib.h" |
a5b1863e | 38 | #include "splay-tree.h" |
c2e94b25 | 39 | #include "ggc.h" |
b0278d39 | 40 | #include "langhooks.h" |
4f8e9d5c | 41 | #include "target.h" |
a5b1863e | 42 | |
43 | /* The alias sets assigned to MEMs assist the back-end in determining | |
44 | which MEMs can alias which other MEMs. In general, two MEMs in | |
5badbbc0 | 45 | different alias sets cannot alias each other, with one important |
46 | exception. Consider something like: | |
a5b1863e | 47 | |
48 | struct S {int i; double d; }; | |
49 | ||
50 | a store to an `S' can alias something of either type `int' or type | |
51 | `double'. (However, a store to an `int' cannot alias a `double' | |
52 | and vice versa.) We indicate this via a tree structure that looks | |
53 | like: | |
54 | struct S | |
55 | / \ | |
56 | / \ | |
57 | |/_ _\| | |
58 | int double | |
59 | ||
5badbbc0 | 60 | (The arrows are directed and point downwards.) |
61 | In this situation we say the alias set for `struct S' is the | |
62 | `superset' and that those for `int' and `double' are `subsets'. | |
63 | ||
f7c44134 | 64 | To see whether two alias sets can point to the same memory, we must |
65 | see if either alias set is a subset of the other. We need not trace | |
b9fe4edd | 66 | past immediate descendents, however, since we propagate all |
f7c44134 | 67 | grandchildren up one level. |
a5b1863e | 68 | |
69 | Alias set zero is implicitly a superset of all other alias sets. | |
70 | However, this is no actual entry for alias set zero. It is an | |
71 | error to attempt to explicitly construct a subset of zero. */ | |
72 | ||
083a2b5e | 73 | typedef struct alias_set_entry |
74 | { | |
a5b1863e | 75 | /* The alias set number, as stored in MEM_ALIAS_SET. */ |
f7c44134 | 76 | HOST_WIDE_INT alias_set; |
a5b1863e | 77 | |
78 | /* The children of the alias set. These are not just the immediate | |
b9fe4edd | 79 | children, but, in fact, all descendents. So, if we have: |
a5b1863e | 80 | |
9342ee68 | 81 | struct T { struct S s; float f; } |
a5b1863e | 82 | |
83 | continuing our example above, the children here will be all of | |
84 | `int', `double', `float', and `struct S'. */ | |
85 | splay_tree children; | |
851dfbff | 86 | |
87 | /* Nonzero if would have a child of zero: this effectively makes this | |
88 | alias set the same as alias set zero. */ | |
89 | int has_zero_child; | |
083a2b5e | 90 | } *alias_set_entry; |
ea0cb7ae | 91 | |
6bcfea9e | 92 | static int rtx_equal_for_memref_p PARAMS ((rtx, rtx)); |
93 | static rtx find_symbolic_term PARAMS ((rtx)); | |
8e802be9 | 94 | rtx get_addr PARAMS ((rtx)); |
6bcfea9e | 95 | static int memrefs_conflict_p PARAMS ((int, rtx, int, rtx, |
96 | HOST_WIDE_INT)); | |
97 | static void record_set PARAMS ((rtx, rtx, void *)); | |
98 | static rtx find_base_term PARAMS ((rtx)); | |
99 | static int base_alias_check PARAMS ((rtx, rtx, enum machine_mode, | |
100 | enum machine_mode)); | |
101 | static rtx find_base_value PARAMS ((rtx)); | |
102 | static int mems_in_disjoint_alias_sets_p PARAMS ((rtx, rtx)); | |
103 | static int insert_subset_children PARAMS ((splay_tree_node, void*)); | |
96216d37 | 104 | static tree find_base_decl PARAMS ((tree)); |
f7c44134 | 105 | static alias_set_entry get_alias_set_entry PARAMS ((HOST_WIDE_INT)); |
1617c276 | 106 | static rtx fixed_scalar_and_varying_struct_p PARAMS ((rtx, rtx, rtx, rtx, |
ea087693 | 107 | int (*) (rtx, int))); |
6bcfea9e | 108 | static int aliases_everything_p PARAMS ((rtx)); |
b10dbbca | 109 | static bool nonoverlapping_component_refs_p PARAMS ((tree, tree)); |
110 | static tree decl_for_component_ref PARAMS ((tree)); | |
111 | static rtx adjust_offset_for_component_ref PARAMS ((tree, rtx)); | |
ddb3d16f | 112 | static int nonoverlapping_memrefs_p PARAMS ((rtx, rtx)); |
6bcfea9e | 113 | static int write_dependence_p PARAMS ((rtx, rtx, int)); |
c352cbc7 | 114 | |
115 | static int nonlocal_mentioned_p_1 PARAMS ((rtx *, void *)); | |
1addbe73 | 116 | static int nonlocal_mentioned_p PARAMS ((rtx)); |
c352cbc7 | 117 | static int nonlocal_referenced_p_1 PARAMS ((rtx *, void *)); |
118 | static int nonlocal_referenced_p PARAMS ((rtx)); | |
119 | static int nonlocal_set_p_1 PARAMS ((rtx *, void *)); | |
120 | static int nonlocal_set_p PARAMS ((rtx)); | |
ea0cb7ae | 121 | |
122 | /* Set up all info needed to perform alias analysis on memory references. */ | |
123 | ||
083a2b5e | 124 | /* Returns the size in bytes of the mode of X. */ |
ea0cb7ae | 125 | #define SIZE_FOR_MODE(X) (GET_MODE_SIZE (GET_MODE (X))) |
126 | ||
b5ba9f3a | 127 | /* Returns nonzero if MEM1 and MEM2 do not alias because they are in |
a068b2a9 | 128 | different alias sets. We ignore alias sets in functions making use |
129 | of variable arguments because the va_arg macros on some systems are | |
130 | not legal ANSI C. */ | |
131 | #define DIFFERENT_ALIAS_SETS_P(MEM1, MEM2) \ | |
a5b1863e | 132 | mems_in_disjoint_alias_sets_p (MEM1, MEM2) |
b5ba9f3a | 133 | |
37b864db | 134 | /* Cap the number of passes we make over the insns propagating alias |
5badbbc0 | 135 | information through set chains. 10 is a completely arbitrary choice. */ |
37b864db | 136 | #define MAX_ALIAS_LOOP_PASSES 10 |
9342ee68 | 137 | |
ea0cb7ae | 138 | /* reg_base_value[N] gives an address to which register N is related. |
139 | If all sets after the first add or subtract to the current value | |
140 | or otherwise modify it so it does not point to a different top level | |
141 | object, reg_base_value[N] is equal to the address part of the source | |
e7c893ba | 142 | of the first set. |
143 | ||
144 | A base address can be an ADDRESS, SYMBOL_REF, or LABEL_REF. ADDRESS | |
145 | expressions represent certain special values: function arguments and | |
9342ee68 | 146 | the stack, frame, and argument pointers. |
3a935f06 | 147 | |
148 | The contents of an ADDRESS is not normally used, the mode of the | |
149 | ADDRESS determines whether the ADDRESS is a function argument or some | |
150 | other special value. Pointer equality, not rtx_equal_p, determines whether | |
151 | two ADDRESS expressions refer to the same base address. | |
152 | ||
153 | The only use of the contents of an ADDRESS is for determining if the | |
154 | current function performs nonlocal memory memory references for the | |
155 | purposes of marking the function as a constant function. */ | |
e7c893ba | 156 | |
1f3233d1 | 157 | static GTY((length ("reg_base_value_size"))) rtx *reg_base_value; |
c2e94b25 | 158 | static rtx *new_reg_base_value; |
083a2b5e | 159 | static unsigned int reg_base_value_size; /* size of reg_base_value array */ |
160 | ||
0c7f5242 | 161 | /* Static hunks of RTL used by the aliasing code; these are initialized |
162 | once per function to avoid unnecessary RTL allocations. */ | |
163 | static GTY (()) rtx static_reg_base_value[FIRST_PSEUDO_REGISTER]; | |
164 | ||
ea0cb7ae | 165 | #define REG_BASE_VALUE(X) \ |
9db10305 | 166 | (REGNO (X) < reg_base_value_size \ |
167 | ? reg_base_value[REGNO (X)] : 0) | |
ea0cb7ae | 168 | |
1a6c3add | 169 | /* Vector of known invariant relationships between registers. Set in |
170 | loop unrolling. Indexed by register number, if nonzero the value | |
171 | is an expression describing this register in terms of another. | |
172 | ||
173 | The length of this array is REG_BASE_VALUE_SIZE. | |
174 | ||
175 | Because this array contains only pseudo registers it has no effect | |
176 | after reload. */ | |
177 | static rtx *alias_invariant; | |
178 | ||
73f5c1e3 | 179 | /* Vector indexed by N giving the initial (unchanging) value known for |
180 | pseudo-register N. This array is initialized in | |
181 | init_alias_analysis, and does not change until end_alias_analysis | |
182 | is called. */ | |
ea0cb7ae | 183 | rtx *reg_known_value; |
184 | ||
185 | /* Indicates number of valid entries in reg_known_value. */ | |
02e7a332 | 186 | static unsigned int reg_known_value_size; |
ea0cb7ae | 187 | |
188 | /* Vector recording for each reg_known_value whether it is due to a | |
189 | REG_EQUIV note. Future passes (viz., reload) may replace the | |
190 | pseudo with the equivalent expression and so we account for the | |
5badbbc0 | 191 | dependences that would be introduced if that happens. |
192 | ||
193 | The REG_EQUIV notes created in assign_parms may mention the arg | |
194 | pointer, and there are explicit insns in the RTL that modify the | |
195 | arg pointer. Thus we must ensure that such insns don't get | |
196 | scheduled across each other because that would invalidate the | |
197 | REG_EQUIV notes. One could argue that the REG_EQUIV notes are | |
198 | wrong, but solving the problem in the scheduler will likely give | |
199 | better code, so we do it here. */ | |
ea0cb7ae | 200 | char *reg_known_equiv_p; |
201 | ||
e7c893ba | 202 | /* True when scanning insns from the start of the rtl to the |
203 | NOTE_INSN_FUNCTION_BEG note. */ | |
e5be0cc6 | 204 | static bool copying_arguments; |
ea0cb7ae | 205 | |
a5b1863e | 206 | /* The splay-tree used to store the various alias set entries. */ |
a5b1863e | 207 | static splay_tree alias_sets; |
5badbbc0 | 208 | \f |
a5b1863e | 209 | /* Returns a pointer to the alias set entry for ALIAS_SET, if there is |
210 | such an entry, or NULL otherwise. */ | |
211 | ||
212 | static alias_set_entry | |
213 | get_alias_set_entry (alias_set) | |
f7c44134 | 214 | HOST_WIDE_INT alias_set; |
a5b1863e | 215 | { |
083a2b5e | 216 | splay_tree_node sn |
217 | = splay_tree_lookup (alias_sets, (splay_tree_key) alias_set); | |
a5b1863e | 218 | |
083a2b5e | 219 | return sn != 0 ? ((alias_set_entry) sn->value) : 0; |
a5b1863e | 220 | } |
221 | ||
5badbbc0 | 222 | /* Returns nonzero if the alias sets for MEM1 and MEM2 are such that |
223 | the two MEMs cannot alias each other. */ | |
a5b1863e | 224 | |
9342ee68 | 225 | static int |
a5b1863e | 226 | mems_in_disjoint_alias_sets_p (mem1, mem2) |
227 | rtx mem1; | |
228 | rtx mem2; | |
229 | { | |
9342ee68 | 230 | #ifdef ENABLE_CHECKING |
a5b1863e | 231 | /* Perform a basic sanity check. Namely, that there are no alias sets |
232 | if we're not using strict aliasing. This helps to catch bugs | |
233 | whereby someone uses PUT_CODE, but doesn't clear MEM_ALIAS_SET, or | |
234 | where a MEM is allocated in some way other than by the use of | |
235 | gen_rtx_MEM, and the MEM_ALIAS_SET is not cleared. If we begin to | |
236 | use alias sets to indicate that spilled registers cannot alias each | |
237 | other, we might need to remove this check. */ | |
083a2b5e | 238 | if (! flag_strict_aliasing |
239 | && (MEM_ALIAS_SET (mem1) != 0 || MEM_ALIAS_SET (mem2) != 0)) | |
a5b1863e | 240 | abort (); |
241 | #endif | |
242 | ||
387bc205 | 243 | return ! alias_sets_conflict_p (MEM_ALIAS_SET (mem1), MEM_ALIAS_SET (mem2)); |
244 | } | |
a5b1863e | 245 | |
387bc205 | 246 | /* Insert the NODE into the splay tree given by DATA. Used by |
247 | record_alias_subset via splay_tree_foreach. */ | |
248 | ||
249 | static int | |
250 | insert_subset_children (node, data) | |
251 | splay_tree_node node; | |
252 | void *data; | |
253 | { | |
254 | splay_tree_insert ((splay_tree) data, node->key, node->value); | |
255 | ||
256 | return 0; | |
257 | } | |
258 | ||
259 | /* Return 1 if the two specified alias sets may conflict. */ | |
260 | ||
261 | int | |
262 | alias_sets_conflict_p (set1, set2) | |
263 | HOST_WIDE_INT set1, set2; | |
264 | { | |
265 | alias_set_entry ase; | |
266 | ||
267 | /* If have no alias set information for one of the operands, we have | |
268 | to assume it can alias anything. */ | |
269 | if (set1 == 0 || set2 == 0 | |
270 | /* If the two alias sets are the same, they may alias. */ | |
271 | || set1 == set2) | |
272 | return 1; | |
a5b1863e | 273 | |
f7c44134 | 274 | /* See if the first alias set is a subset of the second. */ |
387bc205 | 275 | ase = get_alias_set_entry (set1); |
851dfbff | 276 | if (ase != 0 |
277 | && (ase->has_zero_child | |
278 | || splay_tree_lookup (ase->children, | |
387bc205 | 279 | (splay_tree_key) set2))) |
280 | return 1; | |
a5b1863e | 281 | |
282 | /* Now do the same, but with the alias sets reversed. */ | |
387bc205 | 283 | ase = get_alias_set_entry (set2); |
851dfbff | 284 | if (ase != 0 |
285 | && (ase->has_zero_child | |
286 | || splay_tree_lookup (ase->children, | |
387bc205 | 287 | (splay_tree_key) set1))) |
288 | return 1; | |
a5b1863e | 289 | |
387bc205 | 290 | /* The two alias sets are distinct and neither one is the |
a5b1863e | 291 | child of the other. Therefore, they cannot alias. */ |
387bc205 | 292 | return 0; |
a5b1863e | 293 | } |
387bc205 | 294 | \f |
295 | /* Return 1 if TYPE is a RECORD_TYPE, UNION_TYPE, or QUAL_UNION_TYPE and has | |
296 | has any readonly fields. If any of the fields have types that | |
297 | contain readonly fields, return true as well. */ | |
a5b1863e | 298 | |
387bc205 | 299 | int |
300 | readonly_fields_p (type) | |
301 | tree type; | |
a5b1863e | 302 | { |
387bc205 | 303 | tree field; |
304 | ||
305 | if (TREE_CODE (type) != RECORD_TYPE && TREE_CODE (type) != UNION_TYPE | |
306 | && TREE_CODE (type) != QUAL_UNION_TYPE) | |
307 | return 0; | |
308 | ||
309 | for (field = TYPE_FIELDS (type); field != 0; field = TREE_CHAIN (field)) | |
310 | if (TREE_CODE (field) == FIELD_DECL | |
311 | && (TREE_READONLY (field) | |
312 | || readonly_fields_p (TREE_TYPE (field)))) | |
313 | return 1; | |
a5b1863e | 314 | |
315 | return 0; | |
316 | } | |
f7c44134 | 317 | \f |
387bc205 | 318 | /* Return 1 if any MEM object of type T1 will always conflict (using the |
319 | dependency routines in this file) with any MEM object of type T2. | |
320 | This is used when allocating temporary storage. If T1 and/or T2 are | |
321 | NULL_TREE, it means we know nothing about the storage. */ | |
322 | ||
323 | int | |
324 | objects_must_conflict_p (t1, t2) | |
325 | tree t1, t2; | |
326 | { | |
218eb8d0 | 327 | /* If neither has a type specified, we don't know if they'll conflict |
328 | because we may be using them to store objects of various types, for | |
329 | example the argument and local variables areas of inlined functions. */ | |
8f2ba9c9 | 330 | if (t1 == 0 && t2 == 0) |
218eb8d0 | 331 | return 0; |
332 | ||
bd881992 | 333 | /* If one or the other has readonly fields or is readonly, |
334 | then they may not conflict. */ | |
335 | if ((t1 != 0 && readonly_fields_p (t1)) | |
336 | || (t2 != 0 && readonly_fields_p (t2)) | |
25763d80 | 337 | || (t1 != 0 && lang_hooks.honor_readonly && TYPE_READONLY (t1)) |
338 | || (t2 != 0 && lang_hooks.honor_readonly && TYPE_READONLY (t2))) | |
bd881992 | 339 | return 0; |
340 | ||
387bc205 | 341 | /* If they are the same type, they must conflict. */ |
342 | if (t1 == t2 | |
343 | /* Likewise if both are volatile. */ | |
344 | || (t1 != 0 && TYPE_VOLATILE (t1) && t2 != 0 && TYPE_VOLATILE (t2))) | |
345 | return 1; | |
346 | ||
bd881992 | 347 | /* If one is aggregate and the other is scalar then they may not |
348 | conflict. */ | |
349 | if ((t1 != 0 && AGGREGATE_TYPE_P (t1)) | |
350 | != (t2 != 0 && AGGREGATE_TYPE_P (t2))) | |
387bc205 | 351 | return 0; |
352 | ||
2c0e001b | 353 | /* Otherwise they conflict only if the alias sets conflict. */ |
387bc205 | 354 | return alias_sets_conflict_p (t1 ? get_alias_set (t1) : 0, |
355 | t2 ? get_alias_set (t2) : 0); | |
356 | } | |
357 | \f | |
f7c44134 | 358 | /* T is an expression with pointer type. Find the DECL on which this |
359 | expression is based. (For example, in `a[i]' this would be `a'.) | |
360 | If there is no such DECL, or a unique decl cannot be determined, | |
35a3065a | 361 | NULL_TREE is returned. */ |
f7c44134 | 362 | |
363 | static tree | |
364 | find_base_decl (t) | |
365 | tree t; | |
366 | { | |
367 | tree d0, d1, d2; | |
368 | ||
369 | if (t == 0 || t == error_mark_node || ! POINTER_TYPE_P (TREE_TYPE (t))) | |
370 | return 0; | |
371 | ||
372 | /* If this is a declaration, return it. */ | |
373 | if (TREE_CODE_CLASS (TREE_CODE (t)) == 'd') | |
374 | return t; | |
375 | ||
376 | /* Handle general expressions. It would be nice to deal with | |
377 | COMPONENT_REFs here. If we could tell that `a' and `b' were the | |
378 | same, then `a->f' and `b->f' are also the same. */ | |
379 | switch (TREE_CODE_CLASS (TREE_CODE (t))) | |
380 | { | |
381 | case '1': | |
382 | return find_base_decl (TREE_OPERAND (t, 0)); | |
383 | ||
384 | case '2': | |
385 | /* Return 0 if found in neither or both are the same. */ | |
386 | d0 = find_base_decl (TREE_OPERAND (t, 0)); | |
387 | d1 = find_base_decl (TREE_OPERAND (t, 1)); | |
388 | if (d0 == d1) | |
389 | return d0; | |
390 | else if (d0 == 0) | |
391 | return d1; | |
392 | else if (d1 == 0) | |
393 | return d0; | |
394 | else | |
395 | return 0; | |
396 | ||
397 | case '3': | |
398 | d0 = find_base_decl (TREE_OPERAND (t, 0)); | |
399 | d1 = find_base_decl (TREE_OPERAND (t, 1)); | |
f7c44134 | 400 | d2 = find_base_decl (TREE_OPERAND (t, 2)); |
401 | ||
402 | /* Set any nonzero values from the last, then from the first. */ | |
403 | if (d1 == 0) d1 = d2; | |
404 | if (d0 == 0) d0 = d1; | |
405 | if (d1 == 0) d1 = d0; | |
406 | if (d2 == 0) d2 = d1; | |
407 | ||
408 | /* At this point all are nonzero or all are zero. If all three are the | |
409 | same, return it. Otherwise, return zero. */ | |
410 | return (d0 == d1 && d1 == d2) ? d0 : 0; | |
411 | ||
412 | default: | |
413 | return 0; | |
414 | } | |
415 | } | |
416 | ||
bd32979f | 417 | /* Return 1 if all the nested component references handled by |
418 | get_inner_reference in T are such that we can address the object in T. */ | |
419 | ||
5cc193e7 | 420 | int |
bd32979f | 421 | can_address_p (t) |
422 | tree t; | |
423 | { | |
424 | /* If we're at the end, it is vacuously addressable. */ | |
425 | if (! handled_component_p (t)) | |
426 | return 1; | |
427 | ||
428 | /* Bitfields are never addressable. */ | |
429 | else if (TREE_CODE (t) == BIT_FIELD_REF) | |
430 | return 0; | |
431 | ||
2a631e19 | 432 | /* Fields are addressable unless they are marked as nonaddressable or |
433 | the containing type has alias set 0. */ | |
bd32979f | 434 | else if (TREE_CODE (t) == COMPONENT_REF |
435 | && ! DECL_NONADDRESSABLE_P (TREE_OPERAND (t, 1)) | |
2a631e19 | 436 | && get_alias_set (TREE_TYPE (TREE_OPERAND (t, 0))) != 0 |
bd32979f | 437 | && can_address_p (TREE_OPERAND (t, 0))) |
438 | return 1; | |
439 | ||
2a631e19 | 440 | /* Likewise for arrays. */ |
ba04d9d5 | 441 | else if ((TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF) |
bd32979f | 442 | && ! TYPE_NONALIASED_COMPONENT (TREE_TYPE (TREE_OPERAND (t, 0))) |
2a631e19 | 443 | && get_alias_set (TREE_TYPE (TREE_OPERAND (t, 0))) != 0 |
bd32979f | 444 | && can_address_p (TREE_OPERAND (t, 0))) |
445 | return 1; | |
446 | ||
447 | return 0; | |
448 | } | |
449 | ||
f7c44134 | 450 | /* Return the alias set for T, which may be either a type or an |
451 | expression. Call language-specific routine for help, if needed. */ | |
452 | ||
453 | HOST_WIDE_INT | |
454 | get_alias_set (t) | |
455 | tree t; | |
456 | { | |
457 | HOST_WIDE_INT set; | |
f7c44134 | 458 | |
459 | /* If we're not doing any alias analysis, just assume everything | |
460 | aliases everything else. Also return 0 if this or its type is | |
461 | an error. */ | |
462 | if (! flag_strict_aliasing || t == error_mark_node | |
463 | || (! TYPE_P (t) | |
464 | && (TREE_TYPE (t) == 0 || TREE_TYPE (t) == error_mark_node))) | |
465 | return 0; | |
466 | ||
467 | /* We can be passed either an expression or a type. This and the | |
c3a9c149 | 468 | language-specific routine may make mutually-recursive calls to each other |
469 | to figure out what to do. At each juncture, we see if this is a tree | |
470 | that the language may need to handle specially. First handle things that | |
96216d37 | 471 | aren't types. */ |
1607663f | 472 | if (! TYPE_P (t)) |
f7c44134 | 473 | { |
96216d37 | 474 | tree inner = t; |
475 | tree placeholder_ptr = 0; | |
476 | ||
2a631e19 | 477 | /* Remove any nops, then give the language a chance to do |
478 | something with this tree before we look at it. */ | |
479 | STRIP_NOPS (t); | |
480 | set = (*lang_hooks.get_alias_set) (t); | |
481 | if (set != -1) | |
482 | return set; | |
483 | ||
96216d37 | 484 | /* First see if the actual object referenced is an INDIRECT_REF from a |
2a631e19 | 485 | restrict-qualified pointer or a "void *". Replace |
96216d37 | 486 | PLACEHOLDER_EXPRs. */ |
2a631e19 | 487 | while (TREE_CODE (inner) == PLACEHOLDER_EXPR |
96216d37 | 488 | || handled_component_p (inner)) |
489 | { | |
490 | if (TREE_CODE (inner) == PLACEHOLDER_EXPR) | |
491 | inner = find_placeholder (inner, &placeholder_ptr); | |
492 | else | |
493 | inner = TREE_OPERAND (inner, 0); | |
2a631e19 | 494 | |
495 | STRIP_NOPS (inner); | |
96216d37 | 496 | } |
497 | ||
498 | /* Check for accesses through restrict-qualified pointers. */ | |
499 | if (TREE_CODE (inner) == INDIRECT_REF) | |
500 | { | |
501 | tree decl = find_base_decl (TREE_OPERAND (inner, 0)); | |
502 | ||
503 | if (decl && DECL_POINTER_ALIAS_SET_KNOWN_P (decl)) | |
504 | { | |
4e69477b | 505 | /* If we haven't computed the actual alias set, do it now. */ |
96216d37 | 506 | if (DECL_POINTER_ALIAS_SET (decl) == -2) |
507 | { | |
508 | /* No two restricted pointers can point at the same thing. | |
509 | However, a restricted pointer can point at the same thing | |
510 | as an unrestricted pointer, if that unrestricted pointer | |
511 | is based on the restricted pointer. So, we make the | |
512 | alias set for the restricted pointer a subset of the | |
513 | alias set for the type pointed to by the type of the | |
514 | decl. */ | |
515 | HOST_WIDE_INT pointed_to_alias_set | |
516 | = get_alias_set (TREE_TYPE (TREE_TYPE (decl))); | |
517 | ||
518 | if (pointed_to_alias_set == 0) | |
519 | /* It's not legal to make a subset of alias set zero. */ | |
520 | ; | |
521 | else | |
522 | { | |
523 | DECL_POINTER_ALIAS_SET (decl) = new_alias_set (); | |
9342ee68 | 524 | record_alias_subset (pointed_to_alias_set, |
525 | DECL_POINTER_ALIAS_SET (decl)); | |
96216d37 | 526 | } |
527 | } | |
528 | ||
529 | /* We use the alias set indicated in the declaration. */ | |
530 | return DECL_POINTER_ALIAS_SET (decl); | |
531 | } | |
532 | ||
533 | /* If we have an INDIRECT_REF via a void pointer, we don't | |
534 | know anything about what that might alias. */ | |
535 | else if (TREE_CODE (TREE_TYPE (inner)) == VOID_TYPE) | |
536 | return 0; | |
537 | } | |
538 | ||
539 | /* Otherwise, pick up the outermost object that we could have a pointer | |
540 | to, processing conversion and PLACEHOLDER_EXPR as above. */ | |
541 | placeholder_ptr = 0; | |
2a631e19 | 542 | while (TREE_CODE (t) == PLACEHOLDER_EXPR |
c3a9c149 | 543 | || (handled_component_p (t) && ! can_address_p (t))) |
544 | { | |
c3a9c149 | 545 | if (TREE_CODE (t) == PLACEHOLDER_EXPR) |
96216d37 | 546 | t = find_placeholder (t, &placeholder_ptr); |
c3a9c149 | 547 | else |
548 | t = TREE_OPERAND (t, 0); | |
1607663f | 549 | |
2a631e19 | 550 | STRIP_NOPS (t); |
551 | } | |
1607663f | 552 | |
96216d37 | 553 | /* If we've already determined the alias set for a decl, just return |
554 | it. This is necessary for C++ anonymous unions, whose component | |
555 | variables don't look like union members (boo!). */ | |
afce1f57 | 556 | if (TREE_CODE (t) == VAR_DECL |
557 | && DECL_RTL_SET_P (t) && GET_CODE (DECL_RTL (t)) == MEM) | |
558 | return MEM_ALIAS_SET (DECL_RTL (t)); | |
559 | ||
1607663f | 560 | /* Now all we care about is the type. */ |
561 | t = TREE_TYPE (t); | |
f7c44134 | 562 | } |
563 | ||
f7c44134 | 564 | /* Variant qualifiers don't affect the alias set, so get the main |
565 | variant. If this is a type with a known alias set, return it. */ | |
566 | t = TYPE_MAIN_VARIANT (t); | |
96216d37 | 567 | if (TYPE_ALIAS_SET_KNOWN_P (t)) |
f7c44134 | 568 | return TYPE_ALIAS_SET (t); |
569 | ||
570 | /* See if the language has special handling for this type. */ | |
2a631e19 | 571 | set = (*lang_hooks.get_alias_set) (t); |
572 | if (set != -1) | |
96216d37 | 573 | return set; |
851dfbff | 574 | |
f7c44134 | 575 | /* There are no objects of FUNCTION_TYPE, so there's no point in |
576 | using up an alias set for them. (There are, of course, pointers | |
577 | and references to functions, but that's different.) */ | |
578 | else if (TREE_CODE (t) == FUNCTION_TYPE) | |
579 | set = 0; | |
9fcc3e54 | 580 | |
581 | /* Unless the language specifies otherwise, let vector types alias | |
582 | their components. This avoids some nasty type punning issues in | |
583 | normal usage. And indeed lets vectors be treated more like an | |
584 | array slice. */ | |
585 | else if (TREE_CODE (t) == VECTOR_TYPE) | |
586 | set = get_alias_set (TREE_TYPE (t)); | |
587 | ||
f7c44134 | 588 | else |
589 | /* Otherwise make a new alias set for this type. */ | |
590 | set = new_alias_set (); | |
591 | ||
592 | TYPE_ALIAS_SET (t) = set; | |
851dfbff | 593 | |
594 | /* If this is an aggregate type, we must record any component aliasing | |
595 | information. */ | |
680210f2 | 596 | if (AGGREGATE_TYPE_P (t) || TREE_CODE (t) == COMPLEX_TYPE) |
851dfbff | 597 | record_component_aliases (t); |
598 | ||
f7c44134 | 599 | return set; |
600 | } | |
601 | ||
602 | /* Return a brand-new alias set. */ | |
603 | ||
604 | HOST_WIDE_INT | |
605 | new_alias_set () | |
606 | { | |
607 | static HOST_WIDE_INT last_alias_set; | |
608 | ||
609 | if (flag_strict_aliasing) | |
610 | return ++last_alias_set; | |
611 | else | |
612 | return 0; | |
613 | } | |
a5b1863e | 614 | |
615 | /* Indicate that things in SUBSET can alias things in SUPERSET, but | |
616 | not vice versa. For example, in C, a store to an `int' can alias a | |
617 | structure containing an `int', but not vice versa. Here, the | |
618 | structure would be the SUPERSET and `int' the SUBSET. This | |
9342ee68 | 619 | function should be called only once per SUPERSET/SUBSET pair. |
a5b1863e | 620 | |
621 | It is illegal for SUPERSET to be zero; everything is implicitly a | |
622 | subset of alias set zero. */ | |
623 | ||
624 | void | |
625 | record_alias_subset (superset, subset) | |
f7c44134 | 626 | HOST_WIDE_INT superset; |
627 | HOST_WIDE_INT subset; | |
a5b1863e | 628 | { |
629 | alias_set_entry superset_entry; | |
630 | alias_set_entry subset_entry; | |
631 | ||
c3a9c149 | 632 | /* It is possible in complex type situations for both sets to be the same, |
633 | in which case we can ignore this operation. */ | |
634 | if (superset == subset) | |
635 | return; | |
636 | ||
a5b1863e | 637 | if (superset == 0) |
638 | abort (); | |
639 | ||
640 | superset_entry = get_alias_set_entry (superset); | |
9342ee68 | 641 | if (superset_entry == 0) |
a5b1863e | 642 | { |
643 | /* Create an entry for the SUPERSET, so that we have a place to | |
644 | attach the SUBSET. */ | |
083a2b5e | 645 | superset_entry |
646 | = (alias_set_entry) xmalloc (sizeof (struct alias_set_entry)); | |
a5b1863e | 647 | superset_entry->alias_set = superset; |
9342ee68 | 648 | superset_entry->children |
d1264606 | 649 | = splay_tree_new (splay_tree_compare_ints, 0, 0); |
f2e5de80 | 650 | superset_entry->has_zero_child = 0; |
083a2b5e | 651 | splay_tree_insert (alias_sets, (splay_tree_key) superset, |
a5b1863e | 652 | (splay_tree_value) superset_entry); |
a5b1863e | 653 | } |
654 | ||
851dfbff | 655 | if (subset == 0) |
656 | superset_entry->has_zero_child = 1; | |
657 | else | |
658 | { | |
659 | subset_entry = get_alias_set_entry (subset); | |
660 | /* If there is an entry for the subset, enter all of its children | |
661 | (if they are not already present) as children of the SUPERSET. */ | |
9342ee68 | 662 | if (subset_entry) |
851dfbff | 663 | { |
664 | if (subset_entry->has_zero_child) | |
665 | superset_entry->has_zero_child = 1; | |
083a2b5e | 666 | |
851dfbff | 667 | splay_tree_foreach (subset_entry->children, insert_subset_children, |
668 | superset_entry->children); | |
669 | } | |
a5b1863e | 670 | |
851dfbff | 671 | /* Enter the SUBSET itself as a child of the SUPERSET. */ |
9342ee68 | 672 | splay_tree_insert (superset_entry->children, |
851dfbff | 673 | (splay_tree_key) subset, 0); |
674 | } | |
a5b1863e | 675 | } |
676 | ||
9501a338 | 677 | /* Record that component types of TYPE, if any, are part of that type for |
678 | aliasing purposes. For record types, we only record component types | |
679 | for fields that are marked addressable. For array types, we always | |
680 | record the component types, so the front end should not call this | |
681 | function if the individual component aren't addressable. */ | |
682 | ||
683 | void | |
684 | record_component_aliases (type) | |
685 | tree type; | |
686 | { | |
f7c44134 | 687 | HOST_WIDE_INT superset = get_alias_set (type); |
9501a338 | 688 | tree field; |
689 | ||
690 | if (superset == 0) | |
691 | return; | |
692 | ||
693 | switch (TREE_CODE (type)) | |
694 | { | |
695 | case ARRAY_TYPE: | |
851dfbff | 696 | if (! TYPE_NONALIASED_COMPONENT (type)) |
697 | record_alias_subset (superset, get_alias_set (TREE_TYPE (type))); | |
9501a338 | 698 | break; |
699 | ||
700 | case RECORD_TYPE: | |
701 | case UNION_TYPE: | |
702 | case QUAL_UNION_TYPE: | |
c5d44e2f | 703 | /* Recursively record aliases for the base classes, if there are any */ |
704 | if (TYPE_BINFO (type) != NULL && TYPE_BINFO_BASETYPES (type) != NULL) | |
9342ee68 | 705 | { |
706 | int i; | |
707 | for (i = 0; i < TREE_VEC_LENGTH (TYPE_BINFO_BASETYPES (type)); i++) | |
708 | { | |
709 | tree binfo = TREE_VEC_ELT (TYPE_BINFO_BASETYPES (type), i); | |
710 | record_alias_subset (superset, | |
c5d44e2f | 711 | get_alias_set (BINFO_TYPE (binfo))); |
9342ee68 | 712 | } |
713 | } | |
9501a338 | 714 | for (field = TYPE_FIELDS (type); field != 0; field = TREE_CHAIN (field)) |
e7bfabe2 | 715 | if (TREE_CODE (field) == FIELD_DECL && ! DECL_NONADDRESSABLE_P (field)) |
851dfbff | 716 | record_alias_subset (superset, get_alias_set (TREE_TYPE (field))); |
9501a338 | 717 | break; |
718 | ||
680210f2 | 719 | case COMPLEX_TYPE: |
720 | record_alias_subset (superset, get_alias_set (TREE_TYPE (type))); | |
721 | break; | |
722 | ||
9501a338 | 723 | default: |
724 | break; | |
725 | } | |
726 | } | |
727 | ||
f7c44134 | 728 | /* Allocate an alias set for use in storing and reading from the varargs |
729 | spill area. */ | |
730 | ||
731 | HOST_WIDE_INT | |
732 | get_varargs_alias_set () | |
733 | { | |
734 | static HOST_WIDE_INT set = -1; | |
735 | ||
736 | if (set == -1) | |
737 | set = new_alias_set (); | |
738 | ||
739 | return set; | |
740 | } | |
741 | ||
742 | /* Likewise, but used for the fixed portions of the frame, e.g., register | |
743 | save areas. */ | |
744 | ||
745 | HOST_WIDE_INT | |
746 | get_frame_alias_set () | |
747 | { | |
748 | static HOST_WIDE_INT set = -1; | |
749 | ||
750 | if (set == -1) | |
751 | set = new_alias_set (); | |
752 | ||
753 | return set; | |
754 | } | |
755 | ||
e7c893ba | 756 | /* Inside SRC, the source of a SET, find a base address. */ |
757 | ||
ea0cb7ae | 758 | static rtx |
759 | find_base_value (src) | |
19cb6b50 | 760 | rtx src; |
ea0cb7ae | 761 | { |
970c0c06 | 762 | unsigned int regno; |
d01410d3 | 763 | |
ea0cb7ae | 764 | switch (GET_CODE (src)) |
765 | { | |
766 | case SYMBOL_REF: | |
767 | case LABEL_REF: | |
768 | return src; | |
769 | ||
770 | case REG: | |
9db10305 | 771 | regno = REGNO (src); |
083a2b5e | 772 | /* At the start of a function, argument registers have known base |
e7c893ba | 773 | values which may be lost later. Returning an ADDRESS |
774 | expression here allows optimization based on argument values | |
775 | even when the argument registers are used for other purposes. */ | |
970c0c06 | 776 | if (regno < FIRST_PSEUDO_REGISTER && copying_arguments) |
777 | return new_reg_base_value[regno]; | |
1a538f67 | 778 | |
ebd13eec | 779 | /* If a pseudo has a known base value, return it. Do not do this |
9464d436 | 780 | for non-fixed hard regs since it can result in a circular |
781 | dependency chain for registers which have values at function entry. | |
ebd13eec | 782 | |
783 | The test above is not sufficient because the scheduler may move | |
784 | a copy out of an arg reg past the NOTE_INSN_FUNCTION_BEGIN. */ | |
9464d436 | 785 | if ((regno >= FIRST_PSEUDO_REGISTER || fixed_regs[regno]) |
e5be0cc6 | 786 | && regno < reg_base_value_size) |
787 | { | |
788 | /* If we're inside init_alias_analysis, use new_reg_base_value | |
789 | to reduce the number of relaxation iterations. */ | |
790 | if (new_reg_base_value && new_reg_base_value[regno]) | |
791 | return new_reg_base_value[regno]; | |
792 | ||
793 | if (reg_base_value[regno]) | |
794 | return reg_base_value[regno]; | |
795 | } | |
1a538f67 | 796 | |
ea0cb7ae | 797 | return src; |
798 | ||
799 | case MEM: | |
800 | /* Check for an argument passed in memory. Only record in the | |
801 | copying-arguments block; it is too hard to track changes | |
802 | otherwise. */ | |
803 | if (copying_arguments | |
804 | && (XEXP (src, 0) == arg_pointer_rtx | |
805 | || (GET_CODE (XEXP (src, 0)) == PLUS | |
806 | && XEXP (XEXP (src, 0), 0) == arg_pointer_rtx))) | |
941522d6 | 807 | return gen_rtx_ADDRESS (VOIDmode, src); |
ea0cb7ae | 808 | return 0; |
809 | ||
810 | case CONST: | |
811 | src = XEXP (src, 0); | |
812 | if (GET_CODE (src) != PLUS && GET_CODE (src) != MINUS) | |
813 | break; | |
083a2b5e | 814 | |
2c0e001b | 815 | /* ... fall through ... */ |
e7c893ba | 816 | |
ea0cb7ae | 817 | case PLUS: |
818 | case MINUS: | |
e7c893ba | 819 | { |
06c5c535 | 820 | rtx temp, src_0 = XEXP (src, 0), src_1 = XEXP (src, 1); |
821 | ||
560de2f8 | 822 | /* If either operand is a REG that is a known pointer, then it |
823 | is the base. */ | |
824 | if (REG_P (src_0) && REG_POINTER (src_0)) | |
825 | return find_base_value (src_0); | |
826 | if (REG_P (src_1) && REG_POINTER (src_1)) | |
827 | return find_base_value (src_1); | |
828 | ||
06c5c535 | 829 | /* If either operand is a REG, then see if we already have |
830 | a known value for it. */ | |
560de2f8 | 831 | if (REG_P (src_0)) |
06c5c535 | 832 | { |
833 | temp = find_base_value (src_0); | |
083a2b5e | 834 | if (temp != 0) |
06c5c535 | 835 | src_0 = temp; |
836 | } | |
837 | ||
560de2f8 | 838 | if (REG_P (src_1)) |
06c5c535 | 839 | { |
840 | temp = find_base_value (src_1); | |
083a2b5e | 841 | if (temp!= 0) |
06c5c535 | 842 | src_1 = temp; |
843 | } | |
e7c893ba | 844 | |
560de2f8 | 845 | /* If either base is named object or a special address |
846 | (like an argument or stack reference), then use it for the | |
847 | base term. */ | |
848 | if (src_0 != 0 | |
849 | && (GET_CODE (src_0) == SYMBOL_REF | |
850 | || GET_CODE (src_0) == LABEL_REF | |
851 | || (GET_CODE (src_0) == ADDRESS | |
852 | && GET_MODE (src_0) != VOIDmode))) | |
853 | return src_0; | |
854 | ||
855 | if (src_1 != 0 | |
856 | && (GET_CODE (src_1) == SYMBOL_REF | |
857 | || GET_CODE (src_1) == LABEL_REF | |
858 | || (GET_CODE (src_1) == ADDRESS | |
859 | && GET_MODE (src_1) != VOIDmode))) | |
860 | return src_1; | |
861 | ||
083a2b5e | 862 | /* Guess which operand is the base address: |
06c5c535 | 863 | If either operand is a symbol, then it is the base. If |
864 | either operand is a CONST_INT, then the other is the base. */ | |
083a2b5e | 865 | if (GET_CODE (src_1) == CONST_INT || CONSTANT_P (src_0)) |
e7c893ba | 866 | return find_base_value (src_0); |
083a2b5e | 867 | else if (GET_CODE (src_0) == CONST_INT || CONSTANT_P (src_1)) |
06c5c535 | 868 | return find_base_value (src_1); |
869 | ||
ea0cb7ae | 870 | return 0; |
e7c893ba | 871 | } |
872 | ||
873 | case LO_SUM: | |
874 | /* The standard form is (lo_sum reg sym) so look only at the | |
875 | second operand. */ | |
876 | return find_base_value (XEXP (src, 1)); | |
ea0cb7ae | 877 | |
878 | case AND: | |
879 | /* If the second operand is constant set the base | |
2c0e001b | 880 | address to the first operand. */ |
e7c893ba | 881 | if (GET_CODE (XEXP (src, 1)) == CONST_INT && INTVAL (XEXP (src, 1)) != 0) |
882 | return find_base_value (XEXP (src, 0)); | |
ea0cb7ae | 883 | return 0; |
884 | ||
43d45282 | 885 | case TRUNCATE: |
886 | if (GET_MODE_SIZE (GET_MODE (src)) < GET_MODE_SIZE (Pmode)) | |
887 | break; | |
888 | /* Fall through. */ | |
ea0cb7ae | 889 | case HIGH: |
2be64ef0 | 890 | case PRE_INC: |
891 | case PRE_DEC: | |
892 | case POST_INC: | |
893 | case POST_DEC: | |
894 | case PRE_MODIFY: | |
895 | case POST_MODIFY: | |
e7c893ba | 896 | return find_base_value (XEXP (src, 0)); |
99c14947 | 897 | |
d01410d3 | 898 | case ZERO_EXTEND: |
899 | case SIGN_EXTEND: /* used for NT/Alpha pointers */ | |
900 | { | |
901 | rtx temp = find_base_value (XEXP (src, 0)); | |
902 | ||
903 | #ifdef POINTERS_EXTEND_UNSIGNED | |
904 | if (temp != 0 && CONSTANT_P (temp) && GET_MODE (temp) != Pmode) | |
905 | temp = convert_memory_address (Pmode, temp); | |
906 | #endif | |
907 | ||
908 | return temp; | |
909 | } | |
910 | ||
99c14947 | 911 | default: |
912 | break; | |
ea0cb7ae | 913 | } |
914 | ||
915 | return 0; | |
916 | } | |
917 | ||
918 | /* Called from init_alias_analysis indirectly through note_stores. */ | |
919 | ||
083a2b5e | 920 | /* While scanning insns to find base values, reg_seen[N] is nonzero if |
ea0cb7ae | 921 | register N has been set in this function. */ |
922 | static char *reg_seen; | |
923 | ||
10882800 | 924 | /* Addresses which are known not to alias anything else are identified |
925 | by a unique integer. */ | |
06c5c535 | 926 | static int unique_id; |
927 | ||
e7c893ba | 928 | static void |
ec8895d7 | 929 | record_set (dest, set, data) |
ea0cb7ae | 930 | rtx dest, set; |
ec8895d7 | 931 | void *data ATTRIBUTE_UNUSED; |
ea0cb7ae | 932 | { |
19cb6b50 | 933 | unsigned regno; |
ea0cb7ae | 934 | rtx src; |
935 | ||
936 | if (GET_CODE (dest) != REG) | |
937 | return; | |
938 | ||
9db10305 | 939 | regno = REGNO (dest); |
ea0cb7ae | 940 | |
c2e94b25 | 941 | if (regno >= reg_base_value_size) |
942 | abort (); | |
943 | ||
ea0cb7ae | 944 | if (set) |
945 | { | |
946 | /* A CLOBBER wipes out any old value but does not prevent a previously | |
947 | unset register from acquiring a base address (i.e. reg_seen is not | |
948 | set). */ | |
949 | if (GET_CODE (set) == CLOBBER) | |
950 | { | |
06c5c535 | 951 | new_reg_base_value[regno] = 0; |
ea0cb7ae | 952 | return; |
953 | } | |
954 | src = SET_SRC (set); | |
955 | } | |
956 | else | |
957 | { | |
ea0cb7ae | 958 | if (reg_seen[regno]) |
959 | { | |
06c5c535 | 960 | new_reg_base_value[regno] = 0; |
ea0cb7ae | 961 | return; |
962 | } | |
963 | reg_seen[regno] = 1; | |
941522d6 | 964 | new_reg_base_value[regno] = gen_rtx_ADDRESS (Pmode, |
965 | GEN_INT (unique_id++)); | |
ea0cb7ae | 966 | return; |
967 | } | |
968 | ||
969 | /* This is not the first set. If the new value is not related to the | |
970 | old value, forget the base value. Note that the following code is | |
971 | not detected: | |
972 | extern int x, y; int *p = &x; p += (&y-&x); | |
973 | ANSI C does not allow computing the difference of addresses | |
974 | of distinct top level objects. */ | |
06c5c535 | 975 | if (new_reg_base_value[regno]) |
ea0cb7ae | 976 | switch (GET_CODE (src)) |
977 | { | |
e7c893ba | 978 | case LO_SUM: |
ea0cb7ae | 979 | case MINUS: |
980 | if (XEXP (src, 0) != dest && XEXP (src, 1) != dest) | |
06c5c535 | 981 | new_reg_base_value[regno] = 0; |
ea0cb7ae | 982 | break; |
43d45282 | 983 | case PLUS: |
984 | /* If the value we add in the PLUS is also a valid base value, | |
985 | this might be the actual base value, and the original value | |
986 | an index. */ | |
987 | { | |
988 | rtx other = NULL_RTX; | |
989 | ||
990 | if (XEXP (src, 0) == dest) | |
991 | other = XEXP (src, 1); | |
992 | else if (XEXP (src, 1) == dest) | |
993 | other = XEXP (src, 0); | |
994 | ||
995 | if (! other || find_base_value (other)) | |
996 | new_reg_base_value[regno] = 0; | |
997 | break; | |
998 | } | |
ea0cb7ae | 999 | case AND: |
1000 | if (XEXP (src, 0) != dest || GET_CODE (XEXP (src, 1)) != CONST_INT) | |
06c5c535 | 1001 | new_reg_base_value[regno] = 0; |
ea0cb7ae | 1002 | break; |
ea0cb7ae | 1003 | default: |
06c5c535 | 1004 | new_reg_base_value[regno] = 0; |
ea0cb7ae | 1005 | break; |
1006 | } | |
1007 | /* If this is the first set of a register, record the value. */ | |
1008 | else if ((regno >= FIRST_PSEUDO_REGISTER || ! fixed_regs[regno]) | |
06c5c535 | 1009 | && ! reg_seen[regno] && new_reg_base_value[regno] == 0) |
1010 | new_reg_base_value[regno] = find_base_value (src); | |
ea0cb7ae | 1011 | |
1012 | reg_seen[regno] = 1; | |
1013 | } | |
1014 | ||
5badbbc0 | 1015 | /* Called from loop optimization when a new pseudo-register is |
1016 | created. It indicates that REGNO is being set to VAL. f INVARIANT | |
1017 | is true then this value also describes an invariant relationship | |
1018 | which can be used to deduce that two registers with unknown values | |
1019 | are different. */ | |
083a2b5e | 1020 | |
ea0cb7ae | 1021 | void |
1a6c3add | 1022 | record_base_value (regno, val, invariant) |
5badbbc0 | 1023 | unsigned int regno; |
ea0cb7ae | 1024 | rtx val; |
1a6c3add | 1025 | int invariant; |
ea0cb7ae | 1026 | { |
5badbbc0 | 1027 | if (regno >= reg_base_value_size) |
ea0cb7ae | 1028 | return; |
1a6c3add | 1029 | |
1a6c3add | 1030 | if (invariant && alias_invariant) |
1031 | alias_invariant[regno] = val; | |
1032 | ||
ea0cb7ae | 1033 | if (GET_CODE (val) == REG) |
1034 | { | |
9db10305 | 1035 | if (REGNO (val) < reg_base_value_size) |
1036 | reg_base_value[regno] = reg_base_value[REGNO (val)]; | |
083a2b5e | 1037 | |
ea0cb7ae | 1038 | return; |
1039 | } | |
083a2b5e | 1040 | |
ea0cb7ae | 1041 | reg_base_value[regno] = find_base_value (val); |
1042 | } | |
1043 | ||
9f5e1a5a | 1044 | /* Clear alias info for a register. This is used if an RTL transformation |
1045 | changes the value of a register. This is used in flow by AUTO_INC_DEC | |
1046 | optimizations. We don't need to clear reg_base_value, since flow only | |
1047 | changes the offset. */ | |
1048 | ||
1049 | void | |
27d0c333 | 1050 | clear_reg_alias_info (reg) |
1051 | rtx reg; | |
9f5e1a5a | 1052 | { |
26c8b134 | 1053 | unsigned int regno = REGNO (reg); |
1054 | ||
1055 | if (regno < reg_known_value_size && regno >= FIRST_PSEUDO_REGISTER) | |
1056 | reg_known_value[regno] = reg; | |
9f5e1a5a | 1057 | } |
1058 | ||
7cfb9bcf | 1059 | /* Returns a canonical version of X, from the point of view alias |
1060 | analysis. (For example, if X is a MEM whose address is a register, | |
1061 | and the register has a known value (say a SYMBOL_REF), then a MEM | |
1062 | whose address is the SYMBOL_REF is returned.) */ | |
1063 | ||
1064 | rtx | |
ea0cb7ae | 1065 | canon_rtx (x) |
1066 | rtx x; | |
1067 | { | |
1068 | /* Recursively look for equivalences. */ | |
9db10305 | 1069 | if (GET_CODE (x) == REG && REGNO (x) >= FIRST_PSEUDO_REGISTER |
1070 | && REGNO (x) < reg_known_value_size) | |
1071 | return reg_known_value[REGNO (x)] == x | |
1072 | ? x : canon_rtx (reg_known_value[REGNO (x)]); | |
ea0cb7ae | 1073 | else if (GET_CODE (x) == PLUS) |
1074 | { | |
1075 | rtx x0 = canon_rtx (XEXP (x, 0)); | |
1076 | rtx x1 = canon_rtx (XEXP (x, 1)); | |
1077 | ||
1078 | if (x0 != XEXP (x, 0) || x1 != XEXP (x, 1)) | |
1079 | { | |
ea0cb7ae | 1080 | if (GET_CODE (x0) == CONST_INT) |
b244d4c7 | 1081 | return plus_constant (x1, INTVAL (x0)); |
ea0cb7ae | 1082 | else if (GET_CODE (x1) == CONST_INT) |
b244d4c7 | 1083 | return plus_constant (x0, INTVAL (x1)); |
941522d6 | 1084 | return gen_rtx_PLUS (GET_MODE (x), x0, x1); |
ea0cb7ae | 1085 | } |
1086 | } | |
083a2b5e | 1087 | |
ea0cb7ae | 1088 | /* This gives us much better alias analysis when called from |
1089 | the loop optimizer. Note we want to leave the original | |
1090 | MEM alone, but need to return the canonicalized MEM with | |
1091 | all the flags with their original values. */ | |
1092 | else if (GET_CODE (x) == MEM) | |
e4e86ec5 | 1093 | x = replace_equiv_address_nv (x, canon_rtx (XEXP (x, 0))); |
083a2b5e | 1094 | |
ea0cb7ae | 1095 | return x; |
1096 | } | |
1097 | ||
1098 | /* Return 1 if X and Y are identical-looking rtx's. | |
1099 | ||
1100 | We use the data in reg_known_value above to see if two registers with | |
1101 | different numbers are, in fact, equivalent. */ | |
1102 | ||
1103 | static int | |
1104 | rtx_equal_for_memref_p (x, y) | |
1105 | rtx x, y; | |
1106 | { | |
19cb6b50 | 1107 | int i; |
1108 | int j; | |
1109 | enum rtx_code code; | |
1110 | const char *fmt; | |
ea0cb7ae | 1111 | |
1112 | if (x == 0 && y == 0) | |
1113 | return 1; | |
1114 | if (x == 0 || y == 0) | |
1115 | return 0; | |
083a2b5e | 1116 | |
ea0cb7ae | 1117 | x = canon_rtx (x); |
1118 | y = canon_rtx (y); | |
1119 | ||
1120 | if (x == y) | |
1121 | return 1; | |
1122 | ||
1123 | code = GET_CODE (x); | |
1124 | /* Rtx's of different codes cannot be equal. */ | |
1125 | if (code != GET_CODE (y)) | |
1126 | return 0; | |
1127 | ||
1128 | /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. | |
1129 | (REG:SI x) and (REG:HI x) are NOT equivalent. */ | |
1130 | ||
1131 | if (GET_MODE (x) != GET_MODE (y)) | |
1132 | return 0; | |
1133 | ||
7cfb9bcf | 1134 | /* Some RTL can be compared without a recursive examination. */ |
1135 | switch (code) | |
1136 | { | |
3d0f529a | 1137 | case VALUE: |
1138 | return CSELIB_VAL_PTR (x) == CSELIB_VAL_PTR (y); | |
1139 | ||
7cfb9bcf | 1140 | case REG: |
1141 | return REGNO (x) == REGNO (y); | |
1142 | ||
1143 | case LABEL_REF: | |
1144 | return XEXP (x, 0) == XEXP (y, 0); | |
9342ee68 | 1145 | |
7cfb9bcf | 1146 | case SYMBOL_REF: |
1147 | return XSTR (x, 0) == XSTR (y, 0); | |
1148 | ||
1149 | case CONST_INT: | |
1150 | case CONST_DOUBLE: | |
1151 | /* There's no need to compare the contents of CONST_DOUBLEs or | |
1152 | CONST_INTs because pointer equality is a good enough | |
1153 | comparison for these nodes. */ | |
1154 | return 0; | |
1155 | ||
1156 | case ADDRESSOF: | |
a1a6acb4 | 1157 | return (XINT (x, 1) == XINT (y, 1) |
1158 | && rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 0))); | |
7cfb9bcf | 1159 | |
1160 | default: | |
1161 | break; | |
1162 | } | |
ea0cb7ae | 1163 | |
1164 | /* For commutative operations, the RTX match if the operand match in any | |
1165 | order. Also handle the simple binary and unary cases without a loop. */ | |
1166 | if (code == EQ || code == NE || GET_RTX_CLASS (code) == 'c') | |
1167 | return ((rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 0)) | |
1168 | && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 1))) | |
1169 | || (rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 1)) | |
1170 | && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 0)))); | |
1171 | else if (GET_RTX_CLASS (code) == '<' || GET_RTX_CLASS (code) == '2') | |
1172 | return (rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 0)) | |
1173 | && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 1))); | |
1174 | else if (GET_RTX_CLASS (code) == '1') | |
1175 | return rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 0)); | |
1176 | ||
1177 | /* Compare the elements. If any pair of corresponding elements | |
1a6c3add | 1178 | fail to match, return 0 for the whole things. |
1179 | ||
1180 | Limit cases to types which actually appear in addresses. */ | |
ea0cb7ae | 1181 | |
1182 | fmt = GET_RTX_FORMAT (code); | |
1183 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
1184 | { | |
1185 | switch (fmt[i]) | |
1186 | { | |
ea0cb7ae | 1187 | case 'i': |
1188 | if (XINT (x, i) != XINT (y, i)) | |
1189 | return 0; | |
1190 | break; | |
1191 | ||
ea0cb7ae | 1192 | case 'E': |
1193 | /* Two vectors must have the same length. */ | |
1194 | if (XVECLEN (x, i) != XVECLEN (y, i)) | |
1195 | return 0; | |
1196 | ||
1197 | /* And the corresponding elements must match. */ | |
1198 | for (j = 0; j < XVECLEN (x, i); j++) | |
083a2b5e | 1199 | if (rtx_equal_for_memref_p (XVECEXP (x, i, j), |
1200 | XVECEXP (y, i, j)) == 0) | |
ea0cb7ae | 1201 | return 0; |
1202 | break; | |
1203 | ||
1204 | case 'e': | |
1205 | if (rtx_equal_for_memref_p (XEXP (x, i), XEXP (y, i)) == 0) | |
1206 | return 0; | |
1207 | break; | |
1208 | ||
83ec925c | 1209 | /* This can happen for asm operands. */ |
1210 | case 's': | |
1211 | if (strcmp (XSTR (x, i), XSTR (y, i))) | |
1212 | return 0; | |
1213 | break; | |
1214 | ||
23c04f6b | 1215 | /* This can happen for an asm which clobbers memory. */ |
1216 | case '0': | |
1217 | break; | |
1218 | ||
ea0cb7ae | 1219 | /* It is believed that rtx's at this level will never |
1220 | contain anything but integers and other rtx's, | |
1221 | except for within LABEL_REFs and SYMBOL_REFs. */ | |
1222 | default: | |
1223 | abort (); | |
1224 | } | |
1225 | } | |
1226 | return 1; | |
1227 | } | |
1228 | ||
1229 | /* Given an rtx X, find a SYMBOL_REF or LABEL_REF within | |
1230 | X and return it, or return 0 if none found. */ | |
1231 | ||
1232 | static rtx | |
1233 | find_symbolic_term (x) | |
1234 | rtx x; | |
1235 | { | |
19cb6b50 | 1236 | int i; |
1237 | enum rtx_code code; | |
1238 | const char *fmt; | |
ea0cb7ae | 1239 | |
1240 | code = GET_CODE (x); | |
1241 | if (code == SYMBOL_REF || code == LABEL_REF) | |
1242 | return x; | |
1243 | if (GET_RTX_CLASS (code) == 'o') | |
1244 | return 0; | |
1245 | ||
1246 | fmt = GET_RTX_FORMAT (code); | |
1247 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
1248 | { | |
1249 | rtx t; | |
1250 | ||
1251 | if (fmt[i] == 'e') | |
1252 | { | |
1253 | t = find_symbolic_term (XEXP (x, i)); | |
1254 | if (t != 0) | |
1255 | return t; | |
1256 | } | |
1257 | else if (fmt[i] == 'E') | |
1258 | break; | |
1259 | } | |
1260 | return 0; | |
1261 | } | |
1262 | ||
1263 | static rtx | |
1264 | find_base_term (x) | |
19cb6b50 | 1265 | rtx x; |
ea0cb7ae | 1266 | { |
1617c276 | 1267 | cselib_val *val; |
1268 | struct elt_loc_list *l; | |
1269 | ||
15750b1e | 1270 | #if defined (FIND_BASE_TERM) |
1271 | /* Try machine-dependent ways to find the base term. */ | |
1272 | x = FIND_BASE_TERM (x); | |
1273 | #endif | |
1274 | ||
ea0cb7ae | 1275 | switch (GET_CODE (x)) |
1276 | { | |
1277 | case REG: | |
1278 | return REG_BASE_VALUE (x); | |
1279 | ||
2be64ef0 | 1280 | case TRUNCATE: |
1281 | if (GET_MODE_SIZE (GET_MODE (x)) < GET_MODE_SIZE (Pmode)) | |
9342ee68 | 1282 | return 0; |
2be64ef0 | 1283 | /* Fall through. */ |
ea0cb7ae | 1284 | case HIGH: |
22dfec7d | 1285 | case PRE_INC: |
1286 | case PRE_DEC: | |
1287 | case POST_INC: | |
1288 | case POST_DEC: | |
2be64ef0 | 1289 | case PRE_MODIFY: |
1290 | case POST_MODIFY: | |
22dfec7d | 1291 | return find_base_term (XEXP (x, 0)); |
1292 | ||
5104ef69 | 1293 | case ZERO_EXTEND: |
1294 | case SIGN_EXTEND: /* Used for Alpha/NT pointers */ | |
1295 | { | |
1296 | rtx temp = find_base_term (XEXP (x, 0)); | |
1297 | ||
1298 | #ifdef POINTERS_EXTEND_UNSIGNED | |
1299 | if (temp != 0 && CONSTANT_P (temp) && GET_MODE (temp) != Pmode) | |
1300 | temp = convert_memory_address (Pmode, temp); | |
1301 | #endif | |
1302 | ||
1303 | return temp; | |
1304 | } | |
1305 | ||
1617c276 | 1306 | case VALUE: |
1307 | val = CSELIB_VAL_PTR (x); | |
1308 | for (l = val->locs; l; l = l->next) | |
1309 | if ((x = find_base_term (l->loc)) != 0) | |
1310 | return x; | |
1311 | return 0; | |
1312 | ||
ea0cb7ae | 1313 | case CONST: |
1314 | x = XEXP (x, 0); | |
1315 | if (GET_CODE (x) != PLUS && GET_CODE (x) != MINUS) | |
1316 | return 0; | |
1317 | /* fall through */ | |
1318 | case LO_SUM: | |
1319 | case PLUS: | |
1320 | case MINUS: | |
1321 | { | |
1b5bbc4c | 1322 | rtx tmp1 = XEXP (x, 0); |
1323 | rtx tmp2 = XEXP (x, 1); | |
1324 | ||
35a3065a | 1325 | /* This is a little bit tricky since we have to determine which of |
1b5bbc4c | 1326 | the two operands represents the real base address. Otherwise this |
1327 | routine may return the index register instead of the base register. | |
1328 | ||
1329 | That may cause us to believe no aliasing was possible, when in | |
1330 | fact aliasing is possible. | |
1331 | ||
1332 | We use a few simple tests to guess the base register. Additional | |
1333 | tests can certainly be added. For example, if one of the operands | |
1334 | is a shift or multiply, then it must be the index register and the | |
1335 | other operand is the base register. */ | |
9342ee68 | 1336 | |
15750b1e | 1337 | if (tmp1 == pic_offset_table_rtx && CONSTANT_P (tmp2)) |
1338 | return find_base_term (tmp2); | |
1339 | ||
1b5bbc4c | 1340 | /* If either operand is known to be a pointer, then use it |
1341 | to determine the base term. */ | |
e61a0a7f | 1342 | if (REG_P (tmp1) && REG_POINTER (tmp1)) |
1b5bbc4c | 1343 | return find_base_term (tmp1); |
1344 | ||
e61a0a7f | 1345 | if (REG_P (tmp2) && REG_POINTER (tmp2)) |
1b5bbc4c | 1346 | return find_base_term (tmp2); |
1347 | ||
1348 | /* Neither operand was known to be a pointer. Go ahead and find the | |
1349 | base term for both operands. */ | |
1350 | tmp1 = find_base_term (tmp1); | |
1351 | tmp2 = find_base_term (tmp2); | |
1352 | ||
1353 | /* If either base term is named object or a special address | |
1354 | (like an argument or stack reference), then use it for the | |
1355 | base term. */ | |
083a2b5e | 1356 | if (tmp1 != 0 |
1b5bbc4c | 1357 | && (GET_CODE (tmp1) == SYMBOL_REF |
1358 | || GET_CODE (tmp1) == LABEL_REF | |
1359 | || (GET_CODE (tmp1) == ADDRESS | |
1360 | && GET_MODE (tmp1) != VOIDmode))) | |
1361 | return tmp1; | |
1362 | ||
083a2b5e | 1363 | if (tmp2 != 0 |
1b5bbc4c | 1364 | && (GET_CODE (tmp2) == SYMBOL_REF |
1365 | || GET_CODE (tmp2) == LABEL_REF | |
1366 | || (GET_CODE (tmp2) == ADDRESS | |
1367 | && GET_MODE (tmp2) != VOIDmode))) | |
1368 | return tmp2; | |
1369 | ||
1370 | /* We could not determine which of the two operands was the | |
1371 | base register and which was the index. So we can determine | |
1372 | nothing from the base alias check. */ | |
1373 | return 0; | |
ea0cb7ae | 1374 | } |
1375 | ||
1376 | case AND: | |
2be64ef0 | 1377 | if (GET_CODE (XEXP (x, 1)) == CONST_INT && INTVAL (XEXP (x, 1)) != 0) |
1378 | return find_base_term (XEXP (x, 0)); | |
ea0cb7ae | 1379 | return 0; |
1380 | ||
1381 | case SYMBOL_REF: | |
1382 | case LABEL_REF: | |
1383 | return x; | |
1384 | ||
7a4fb8f4 | 1385 | case ADDRESSOF: |
7002e559 | 1386 | return REG_BASE_VALUE (frame_pointer_rtx); |
7a4fb8f4 | 1387 | |
ea0cb7ae | 1388 | default: |
1389 | return 0; | |
1390 | } | |
1391 | } | |
1392 | ||
1393 | /* Return 0 if the addresses X and Y are known to point to different | |
1394 | objects, 1 if they might be pointers to the same object. */ | |
1395 | ||
1396 | static int | |
9fb1c31b | 1397 | base_alias_check (x, y, x_mode, y_mode) |
ea0cb7ae | 1398 | rtx x, y; |
9fb1c31b | 1399 | enum machine_mode x_mode, y_mode; |
ea0cb7ae | 1400 | { |
1401 | rtx x_base = find_base_term (x); | |
1402 | rtx y_base = find_base_term (y); | |
1403 | ||
3ad3a0ed | 1404 | /* If the address itself has no known base see if a known equivalent |
1405 | value has one. If either address still has no known base, nothing | |
1406 | is known about aliasing. */ | |
1407 | if (x_base == 0) | |
1408 | { | |
1409 | rtx x_c; | |
083a2b5e | 1410 | |
3ad3a0ed | 1411 | if (! flag_expensive_optimizations || (x_c = canon_rtx (x)) == x) |
1412 | return 1; | |
083a2b5e | 1413 | |
3ad3a0ed | 1414 | x_base = find_base_term (x_c); |
1415 | if (x_base == 0) | |
1416 | return 1; | |
1417 | } | |
ea0cb7ae | 1418 | |
3ad3a0ed | 1419 | if (y_base == 0) |
1420 | { | |
1421 | rtx y_c; | |
1422 | if (! flag_expensive_optimizations || (y_c = canon_rtx (y)) == y) | |
1423 | return 1; | |
083a2b5e | 1424 | |
3ad3a0ed | 1425 | y_base = find_base_term (y_c); |
1426 | if (y_base == 0) | |
1427 | return 1; | |
1428 | } | |
1429 | ||
1430 | /* If the base addresses are equal nothing is known about aliasing. */ | |
1431 | if (rtx_equal_p (x_base, y_base)) | |
ea0cb7ae | 1432 | return 1; |
1433 | ||
9342ee68 | 1434 | /* The base addresses of the read and write are different expressions. |
9fb1c31b | 1435 | If they are both symbols and they are not accessed via AND, there is |
1436 | no conflict. We can bring knowledge of object alignment into play | |
1437 | here. For example, on alpha, "char a, b;" can alias one another, | |
1438 | though "char a; long b;" cannot. */ | |
ea0cb7ae | 1439 | if (GET_CODE (x_base) != ADDRESS && GET_CODE (y_base) != ADDRESS) |
1e38bf49 | 1440 | { |
9fb1c31b | 1441 | if (GET_CODE (x) == AND && GET_CODE (y) == AND) |
1442 | return 1; | |
1443 | if (GET_CODE (x) == AND | |
1444 | && (GET_CODE (XEXP (x, 1)) != CONST_INT | |
8e6c5eac | 1445 | || (int) GET_MODE_UNIT_SIZE (y_mode) < -INTVAL (XEXP (x, 1)))) |
9fb1c31b | 1446 | return 1; |
1447 | if (GET_CODE (y) == AND | |
1448 | && (GET_CODE (XEXP (y, 1)) != CONST_INT | |
8e6c5eac | 1449 | || (int) GET_MODE_UNIT_SIZE (x_mode) < -INTVAL (XEXP (y, 1)))) |
9fb1c31b | 1450 | return 1; |
2b4e2cb9 | 1451 | /* Differing symbols never alias. */ |
1452 | return 0; | |
1e38bf49 | 1453 | } |
ea0cb7ae | 1454 | |
1455 | /* If one address is a stack reference there can be no alias: | |
1456 | stack references using different base registers do not alias, | |
1457 | a stack reference can not alias a parameter, and a stack reference | |
1458 | can not alias a global. */ | |
1459 | if ((GET_CODE (x_base) == ADDRESS && GET_MODE (x_base) == Pmode) | |
1460 | || (GET_CODE (y_base) == ADDRESS && GET_MODE (y_base) == Pmode)) | |
1461 | return 0; | |
1462 | ||
1463 | if (! flag_argument_noalias) | |
1464 | return 1; | |
1465 | ||
1466 | if (flag_argument_noalias > 1) | |
1467 | return 0; | |
1468 | ||
2c0e001b | 1469 | /* Weak noalias assertion (arguments are distinct, but may match globals). */ |
ea0cb7ae | 1470 | return ! (GET_MODE (x_base) == VOIDmode && GET_MODE (y_base) == VOIDmode); |
1471 | } | |
1472 | ||
1617c276 | 1473 | /* Convert the address X into something we can use. This is done by returning |
1474 | it unchanged unless it is a value; in the latter case we call cselib to get | |
1475 | a more useful rtx. */ | |
f7c44134 | 1476 | |
8e802be9 | 1477 | rtx |
1617c276 | 1478 | get_addr (x) |
1479 | rtx x; | |
1480 | { | |
1481 | cselib_val *v; | |
1482 | struct elt_loc_list *l; | |
1483 | ||
1484 | if (GET_CODE (x) != VALUE) | |
1485 | return x; | |
1486 | v = CSELIB_VAL_PTR (x); | |
1487 | for (l = v->locs; l; l = l->next) | |
1488 | if (CONSTANT_P (l->loc)) | |
1489 | return l->loc; | |
1490 | for (l = v->locs; l; l = l->next) | |
1491 | if (GET_CODE (l->loc) != REG && GET_CODE (l->loc) != MEM) | |
1492 | return l->loc; | |
1493 | if (v->locs) | |
1494 | return v->locs->loc; | |
1495 | return x; | |
1496 | } | |
1497 | ||
b9f92976 | 1498 | /* Return the address of the (N_REFS + 1)th memory reference to ADDR |
1499 | where SIZE is the size in bytes of the memory reference. If ADDR | |
1500 | is not modified by the memory reference then ADDR is returned. */ | |
1501 | ||
1502 | rtx | |
1503 | addr_side_effect_eval (addr, size, n_refs) | |
1504 | rtx addr; | |
1505 | int size; | |
1506 | int n_refs; | |
1507 | { | |
1508 | int offset = 0; | |
9342ee68 | 1509 | |
b9f92976 | 1510 | switch (GET_CODE (addr)) |
1511 | { | |
1512 | case PRE_INC: | |
1513 | offset = (n_refs + 1) * size; | |
1514 | break; | |
1515 | case PRE_DEC: | |
1516 | offset = -(n_refs + 1) * size; | |
1517 | break; | |
1518 | case POST_INC: | |
1519 | offset = n_refs * size; | |
1520 | break; | |
1521 | case POST_DEC: | |
1522 | offset = -n_refs * size; | |
1523 | break; | |
1524 | ||
1525 | default: | |
1526 | return addr; | |
1527 | } | |
9342ee68 | 1528 | |
b9f92976 | 1529 | if (offset) |
1530 | addr = gen_rtx_PLUS (GET_MODE (addr), XEXP (addr, 0), GEN_INT (offset)); | |
1531 | else | |
1532 | addr = XEXP (addr, 0); | |
1533 | ||
1534 | return addr; | |
1535 | } | |
1536 | ||
ea0cb7ae | 1537 | /* Return nonzero if X and Y (memory addresses) could reference the |
1538 | same location in memory. C is an offset accumulator. When | |
1539 | C is nonzero, we are testing aliases between X and Y + C. | |
1540 | XSIZE is the size in bytes of the X reference, | |
1541 | similarly YSIZE is the size in bytes for Y. | |
1542 | ||
1543 | If XSIZE or YSIZE is zero, we do not know the amount of memory being | |
1544 | referenced (the reference was BLKmode), so make the most pessimistic | |
1545 | assumptions. | |
1546 | ||
1e38bf49 | 1547 | If XSIZE or YSIZE is negative, we may access memory outside the object |
1548 | being referenced as a side effect. This can happen when using AND to | |
1549 | align memory references, as is done on the Alpha. | |
1550 | ||
ea0cb7ae | 1551 | Nice to notice that varying addresses cannot conflict with fp if no |
4958fe6e | 1552 | local variables had their addresses taken, but that's too hard now. */ |
ea0cb7ae | 1553 | |
ea0cb7ae | 1554 | static int |
1555 | memrefs_conflict_p (xsize, x, ysize, y, c) | |
19cb6b50 | 1556 | rtx x, y; |
ea0cb7ae | 1557 | int xsize, ysize; |
1558 | HOST_WIDE_INT c; | |
1559 | { | |
1617c276 | 1560 | if (GET_CODE (x) == VALUE) |
1561 | x = get_addr (x); | |
1562 | if (GET_CODE (y) == VALUE) | |
1563 | y = get_addr (y); | |
ea0cb7ae | 1564 | if (GET_CODE (x) == HIGH) |
1565 | x = XEXP (x, 0); | |
1566 | else if (GET_CODE (x) == LO_SUM) | |
1567 | x = XEXP (x, 1); | |
1568 | else | |
b9f92976 | 1569 | x = canon_rtx (addr_side_effect_eval (x, xsize, 0)); |
ea0cb7ae | 1570 | if (GET_CODE (y) == HIGH) |
1571 | y = XEXP (y, 0); | |
1572 | else if (GET_CODE (y) == LO_SUM) | |
1573 | y = XEXP (y, 1); | |
1574 | else | |
b9f92976 | 1575 | y = canon_rtx (addr_side_effect_eval (y, ysize, 0)); |
ea0cb7ae | 1576 | |
1577 | if (rtx_equal_for_memref_p (x, y)) | |
1578 | { | |
1e38bf49 | 1579 | if (xsize <= 0 || ysize <= 0) |
ea0cb7ae | 1580 | return 1; |
1581 | if (c >= 0 && xsize > c) | |
1582 | return 1; | |
1583 | if (c < 0 && ysize+c > 0) | |
1584 | return 1; | |
1585 | return 0; | |
1586 | } | |
1587 | ||
35d3eedd | 1588 | /* This code used to check for conflicts involving stack references and |
1589 | globals but the base address alias code now handles these cases. */ | |
ea0cb7ae | 1590 | |
1591 | if (GET_CODE (x) == PLUS) | |
1592 | { | |
1593 | /* The fact that X is canonicalized means that this | |
1594 | PLUS rtx is canonicalized. */ | |
1595 | rtx x0 = XEXP (x, 0); | |
1596 | rtx x1 = XEXP (x, 1); | |
1597 | ||
1598 | if (GET_CODE (y) == PLUS) | |
1599 | { | |
1600 | /* The fact that Y is canonicalized means that this | |
1601 | PLUS rtx is canonicalized. */ | |
1602 | rtx y0 = XEXP (y, 0); | |
1603 | rtx y1 = XEXP (y, 1); | |
1604 | ||
1605 | if (rtx_equal_for_memref_p (x1, y1)) | |
1606 | return memrefs_conflict_p (xsize, x0, ysize, y0, c); | |
1607 | if (rtx_equal_for_memref_p (x0, y0)) | |
1608 | return memrefs_conflict_p (xsize, x1, ysize, y1, c); | |
1609 | if (GET_CODE (x1) == CONST_INT) | |
5f59c49b | 1610 | { |
1611 | if (GET_CODE (y1) == CONST_INT) | |
1612 | return memrefs_conflict_p (xsize, x0, ysize, y0, | |
1613 | c - INTVAL (x1) + INTVAL (y1)); | |
1614 | else | |
1615 | return memrefs_conflict_p (xsize, x0, ysize, y, | |
1616 | c - INTVAL (x1)); | |
1617 | } | |
ea0cb7ae | 1618 | else if (GET_CODE (y1) == CONST_INT) |
1619 | return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1)); | |
1620 | ||
35d3eedd | 1621 | return 1; |
ea0cb7ae | 1622 | } |
1623 | else if (GET_CODE (x1) == CONST_INT) | |
1624 | return memrefs_conflict_p (xsize, x0, ysize, y, c - INTVAL (x1)); | |
1625 | } | |
1626 | else if (GET_CODE (y) == PLUS) | |
1627 | { | |
1628 | /* The fact that Y is canonicalized means that this | |
1629 | PLUS rtx is canonicalized. */ | |
1630 | rtx y0 = XEXP (y, 0); | |
1631 | rtx y1 = XEXP (y, 1); | |
1632 | ||
1633 | if (GET_CODE (y1) == CONST_INT) | |
1634 | return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1)); | |
1635 | else | |
1636 | return 1; | |
1637 | } | |
1638 | ||
1639 | if (GET_CODE (x) == GET_CODE (y)) | |
1640 | switch (GET_CODE (x)) | |
1641 | { | |
1642 | case MULT: | |
1643 | { | |
1644 | /* Handle cases where we expect the second operands to be the | |
1645 | same, and check only whether the first operand would conflict | |
1646 | or not. */ | |
1647 | rtx x0, y0; | |
1648 | rtx x1 = canon_rtx (XEXP (x, 1)); | |
1649 | rtx y1 = canon_rtx (XEXP (y, 1)); | |
1650 | if (! rtx_equal_for_memref_p (x1, y1)) | |
1651 | return 1; | |
1652 | x0 = canon_rtx (XEXP (x, 0)); | |
1653 | y0 = canon_rtx (XEXP (y, 0)); | |
1654 | if (rtx_equal_for_memref_p (x0, y0)) | |
1655 | return (xsize == 0 || ysize == 0 | |
1656 | || (c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)); | |
1657 | ||
1658 | /* Can't properly adjust our sizes. */ | |
1659 | if (GET_CODE (x1) != CONST_INT) | |
1660 | return 1; | |
1661 | xsize /= INTVAL (x1); | |
1662 | ysize /= INTVAL (x1); | |
1663 | c /= INTVAL (x1); | |
1664 | return memrefs_conflict_p (xsize, x0, ysize, y0, c); | |
1665 | } | |
99c14947 | 1666 | |
1a6c3add | 1667 | case REG: |
1668 | /* Are these registers known not to be equal? */ | |
1669 | if (alias_invariant) | |
1670 | { | |
274c11d8 | 1671 | unsigned int r_x = REGNO (x), r_y = REGNO (y); |
1a6c3add | 1672 | rtx i_x, i_y; /* invariant relationships of X and Y */ |
1673 | ||
1674 | i_x = r_x >= reg_base_value_size ? 0 : alias_invariant[r_x]; | |
1675 | i_y = r_y >= reg_base_value_size ? 0 : alias_invariant[r_y]; | |
1676 | ||
1677 | if (i_x == 0 && i_y == 0) | |
1678 | break; | |
1679 | ||
1680 | if (! memrefs_conflict_p (xsize, i_x ? i_x : x, | |
1681 | ysize, i_y ? i_y : y, c)) | |
1682 | return 0; | |
1683 | } | |
1684 | break; | |
1685 | ||
99c14947 | 1686 | default: |
1687 | break; | |
ea0cb7ae | 1688 | } |
1689 | ||
1690 | /* Treat an access through an AND (e.g. a subword access on an Alpha) | |
9342ee68 | 1691 | as an access with indeterminate size. Assume that references |
9fb1c31b | 1692 | besides AND are aligned, so if the size of the other reference is |
1693 | at least as large as the alignment, assume no other overlap. */ | |
ea0cb7ae | 1694 | if (GET_CODE (x) == AND && GET_CODE (XEXP (x, 1)) == CONST_INT) |
9fb1c31b | 1695 | { |
bcdb334e | 1696 | if (GET_CODE (y) == AND || ysize < -INTVAL (XEXP (x, 1))) |
9fb1c31b | 1697 | xsize = -1; |
1698 | return memrefs_conflict_p (xsize, XEXP (x, 0), ysize, y, c); | |
1699 | } | |
ea0cb7ae | 1700 | if (GET_CODE (y) == AND && GET_CODE (XEXP (y, 1)) == CONST_INT) |
1e38bf49 | 1701 | { |
9fb1c31b | 1702 | /* ??? If we are indexing far enough into the array/structure, we |
9342ee68 | 1703 | may yet be able to determine that we can not overlap. But we |
1e38bf49 | 1704 | also need to that we are far enough from the end not to overlap |
9fb1c31b | 1705 | a following reference, so we do nothing with that for now. */ |
bcdb334e | 1706 | if (GET_CODE (x) == AND || xsize < -INTVAL (XEXP (y, 1))) |
9fb1c31b | 1707 | ysize = -1; |
1708 | return memrefs_conflict_p (xsize, x, ysize, XEXP (y, 0), c); | |
1e38bf49 | 1709 | } |
ea0cb7ae | 1710 | |
85e64f58 | 1711 | if (GET_CODE (x) == ADDRESSOF) |
1712 | { | |
1713 | if (y == frame_pointer_rtx | |
1714 | || GET_CODE (y) == ADDRESSOF) | |
1715 | return xsize <= 0 || ysize <= 0; | |
1716 | } | |
1717 | if (GET_CODE (y) == ADDRESSOF) | |
1718 | { | |
1719 | if (x == frame_pointer_rtx) | |
1720 | return xsize <= 0 || ysize <= 0; | |
1721 | } | |
7a4fb8f4 | 1722 | |
ea0cb7ae | 1723 | if (CONSTANT_P (x)) |
1724 | { | |
1725 | if (GET_CODE (x) == CONST_INT && GET_CODE (y) == CONST_INT) | |
1726 | { | |
1727 | c += (INTVAL (y) - INTVAL (x)); | |
1e38bf49 | 1728 | return (xsize <= 0 || ysize <= 0 |
ea0cb7ae | 1729 | || (c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)); |
1730 | } | |
1731 | ||
1732 | if (GET_CODE (x) == CONST) | |
1733 | { | |
1734 | if (GET_CODE (y) == CONST) | |
1735 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), | |
1736 | ysize, canon_rtx (XEXP (y, 0)), c); | |
1737 | else | |
1738 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), | |
1739 | ysize, y, c); | |
1740 | } | |
1741 | if (GET_CODE (y) == CONST) | |
1742 | return memrefs_conflict_p (xsize, x, ysize, | |
1743 | canon_rtx (XEXP (y, 0)), c); | |
1744 | ||
1745 | if (CONSTANT_P (y)) | |
15750b1e | 1746 | return (xsize <= 0 || ysize <= 0 |
1e38bf49 | 1747 | || (rtx_equal_for_memref_p (x, y) |
15750b1e | 1748 | && ((c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)))); |
ea0cb7ae | 1749 | |
1750 | return 1; | |
1751 | } | |
1752 | return 1; | |
1753 | } | |
1754 | ||
1755 | /* Functions to compute memory dependencies. | |
1756 | ||
1757 | Since we process the insns in execution order, we can build tables | |
1758 | to keep track of what registers are fixed (and not aliased), what registers | |
1759 | are varying in known ways, and what registers are varying in unknown | |
1760 | ways. | |
1761 | ||
1762 | If both memory references are volatile, then there must always be a | |
1763 | dependence between the two references, since their order can not be | |
1764 | changed. A volatile and non-volatile reference can be interchanged | |
9342ee68 | 1765 | though. |
ea0cb7ae | 1766 | |
71d9e995 | 1767 | A MEM_IN_STRUCT reference at a non-AND varying address can never |
1768 | conflict with a non-MEM_IN_STRUCT reference at a fixed address. We | |
1769 | also must allow AND addresses, because they may generate accesses | |
1770 | outside the object being referenced. This is used to generate | |
1771 | aligned addresses from unaligned addresses, for instance, the alpha | |
1772 | storeqi_unaligned pattern. */ | |
ea0cb7ae | 1773 | |
1774 | /* Read dependence: X is read after read in MEM takes place. There can | |
1775 | only be a dependence here if both reads are volatile. */ | |
1776 | ||
1777 | int | |
1778 | read_dependence (mem, x) | |
1779 | rtx mem; | |
1780 | rtx x; | |
1781 | { | |
1782 | return MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem); | |
1783 | } | |
1784 | ||
6a0934dd | 1785 | /* Returns MEM1 if and only if MEM1 is a scalar at a fixed address and |
1786 | MEM2 is a reference to a structure at a varying address, or returns | |
1787 | MEM2 if vice versa. Otherwise, returns NULL_RTX. If a non-NULL | |
1788 | value is returned MEM1 and MEM2 can never alias. VARIES_P is used | |
1789 | to decide whether or not an address may vary; it should return | |
1617c276 | 1790 | nonzero whenever variation is possible. |
1791 | MEM1_ADDR and MEM2_ADDR are the addresses of MEM1 and MEM2. */ | |
9342ee68 | 1792 | |
fe69e4fe | 1793 | static rtx |
1617c276 | 1794 | fixed_scalar_and_varying_struct_p (mem1, mem2, mem1_addr, mem2_addr, varies_p) |
1795 | rtx mem1, mem2; | |
1796 | rtx mem1_addr, mem2_addr; | |
ea087693 | 1797 | int (*varies_p) PARAMS ((rtx, int)); |
9342ee68 | 1798 | { |
c7f6877a | 1799 | if (! flag_strict_aliasing) |
1800 | return NULL_RTX; | |
1801 | ||
9342ee68 | 1802 | if (MEM_SCALAR_P (mem1) && MEM_IN_STRUCT_P (mem2) |
ea087693 | 1803 | && !varies_p (mem1_addr, 1) && varies_p (mem2_addr, 1)) |
6a0934dd | 1804 | /* MEM1 is a scalar at a fixed address; MEM2 is a struct at a |
1805 | varying address. */ | |
1806 | return mem1; | |
1807 | ||
9342ee68 | 1808 | if (MEM_IN_STRUCT_P (mem1) && MEM_SCALAR_P (mem2) |
ea087693 | 1809 | && varies_p (mem1_addr, 1) && !varies_p (mem2_addr, 1)) |
6a0934dd | 1810 | /* MEM2 is a scalar at a fixed address; MEM1 is a struct at a |
1811 | varying address. */ | |
1812 | return mem2; | |
1813 | ||
1814 | return NULL_RTX; | |
1815 | } | |
1816 | ||
1817 | /* Returns nonzero if something about the mode or address format MEM1 | |
1818 | indicates that it might well alias *anything*. */ | |
1819 | ||
fe69e4fe | 1820 | static int |
6a0934dd | 1821 | aliases_everything_p (mem) |
1822 | rtx mem; | |
1823 | { | |
6a0934dd | 1824 | if (GET_CODE (XEXP (mem, 0)) == AND) |
1825 | /* If the address is an AND, its very hard to know at what it is | |
1826 | actually pointing. */ | |
1827 | return 1; | |
9342ee68 | 1828 | |
6a0934dd | 1829 | return 0; |
1830 | } | |
1831 | ||
b10dbbca | 1832 | /* Return true if we can determine that the fields referenced cannot |
1833 | overlap for any pair of objects. */ | |
1834 | ||
1835 | static bool | |
1836 | nonoverlapping_component_refs_p (x, y) | |
1837 | tree x, y; | |
1838 | { | |
1839 | tree fieldx, fieldy, typex, typey, orig_y; | |
1840 | ||
1841 | do | |
1842 | { | |
1843 | /* The comparison has to be done at a common type, since we don't | |
cb0ccc1e | 1844 | know how the inheritance hierarchy works. */ |
b10dbbca | 1845 | orig_y = y; |
1846 | do | |
1847 | { | |
1848 | fieldx = TREE_OPERAND (x, 1); | |
1849 | typex = DECL_FIELD_CONTEXT (fieldx); | |
1850 | ||
1851 | y = orig_y; | |
1852 | do | |
1853 | { | |
1854 | fieldy = TREE_OPERAND (y, 1); | |
1855 | typey = DECL_FIELD_CONTEXT (fieldy); | |
1856 | ||
1857 | if (typex == typey) | |
1858 | goto found; | |
1859 | ||
1860 | y = TREE_OPERAND (y, 0); | |
1861 | } | |
1862 | while (y && TREE_CODE (y) == COMPONENT_REF); | |
1863 | ||
1864 | x = TREE_OPERAND (x, 0); | |
1865 | } | |
1866 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
1867 | ||
1868 | /* Never found a common type. */ | |
1869 | return false; | |
1870 | ||
1871 | found: | |
1872 | /* If we're left with accessing different fields of a structure, | |
1873 | then no overlap. */ | |
1874 | if (TREE_CODE (typex) == RECORD_TYPE | |
1875 | && fieldx != fieldy) | |
1876 | return true; | |
1877 | ||
1878 | /* The comparison on the current field failed. If we're accessing | |
1879 | a very nested structure, look at the next outer level. */ | |
1880 | x = TREE_OPERAND (x, 0); | |
1881 | y = TREE_OPERAND (y, 0); | |
1882 | } | |
1883 | while (x && y | |
1884 | && TREE_CODE (x) == COMPONENT_REF | |
1885 | && TREE_CODE (y) == COMPONENT_REF); | |
9342ee68 | 1886 | |
b10dbbca | 1887 | return false; |
1888 | } | |
1889 | ||
1890 | /* Look at the bottom of the COMPONENT_REF list for a DECL, and return it. */ | |
1891 | ||
1892 | static tree | |
1893 | decl_for_component_ref (x) | |
1894 | tree x; | |
1895 | { | |
1896 | do | |
1897 | { | |
1898 | x = TREE_OPERAND (x, 0); | |
1899 | } | |
1900 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
1901 | ||
1902 | return x && DECL_P (x) ? x : NULL_TREE; | |
1903 | } | |
1904 | ||
1905 | /* Walk up the COMPONENT_REF list and adjust OFFSET to compensate for the | |
1906 | offset of the field reference. */ | |
1907 | ||
1908 | static rtx | |
1909 | adjust_offset_for_component_ref (x, offset) | |
1910 | tree x; | |
1911 | rtx offset; | |
1912 | { | |
1913 | HOST_WIDE_INT ioffset; | |
1914 | ||
1915 | if (! offset) | |
1916 | return NULL_RTX; | |
1917 | ||
1918 | ioffset = INTVAL (offset); | |
9342ee68 | 1919 | do |
b10dbbca | 1920 | { |
1921 | tree field = TREE_OPERAND (x, 1); | |
1922 | ||
1923 | if (! host_integerp (DECL_FIELD_OFFSET (field), 1)) | |
1924 | return NULL_RTX; | |
1925 | ioffset += (tree_low_cst (DECL_FIELD_OFFSET (field), 1) | |
1926 | + (tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1) | |
1927 | / BITS_PER_UNIT)); | |
1928 | ||
1929 | x = TREE_OPERAND (x, 0); | |
1930 | } | |
1931 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
1932 | ||
1933 | return GEN_INT (ioffset); | |
1934 | } | |
1935 | ||
1936 | /* Return nonzero if we can deterimine the exprs corresponding to memrefs | |
ddb3d16f | 1937 | X and Y and they do not overlap. */ |
1938 | ||
1939 | static int | |
1940 | nonoverlapping_memrefs_p (x, y) | |
1941 | rtx x, y; | |
1942 | { | |
b10dbbca | 1943 | tree exprx = MEM_EXPR (x), expry = MEM_EXPR (y); |
ddb3d16f | 1944 | rtx rtlx, rtly; |
1945 | rtx basex, basey; | |
b10dbbca | 1946 | rtx moffsetx, moffsety; |
ddb3d16f | 1947 | HOST_WIDE_INT offsetx = 0, offsety = 0, sizex, sizey, tem; |
1948 | ||
b10dbbca | 1949 | /* Unless both have exprs, we can't tell anything. */ |
1950 | if (exprx == 0 || expry == 0) | |
1951 | return 0; | |
1952 | ||
1953 | /* If both are field references, we may be able to determine something. */ | |
1954 | if (TREE_CODE (exprx) == COMPONENT_REF | |
1955 | && TREE_CODE (expry) == COMPONENT_REF | |
1956 | && nonoverlapping_component_refs_p (exprx, expry)) | |
1957 | return 1; | |
1958 | ||
1959 | /* If the field reference test failed, look at the DECLs involved. */ | |
1960 | moffsetx = MEM_OFFSET (x); | |
1961 | if (TREE_CODE (exprx) == COMPONENT_REF) | |
1962 | { | |
1963 | tree t = decl_for_component_ref (exprx); | |
1964 | if (! t) | |
1965 | return 0; | |
1966 | moffsetx = adjust_offset_for_component_ref (exprx, moffsetx); | |
1967 | exprx = t; | |
1968 | } | |
2d8fe5d0 | 1969 | else if (TREE_CODE (exprx) == INDIRECT_REF) |
1970 | { | |
1971 | exprx = TREE_OPERAND (exprx, 0); | |
1972 | if (flag_argument_noalias < 2 | |
1973 | || TREE_CODE (exprx) != PARM_DECL) | |
1974 | return 0; | |
1975 | } | |
1976 | ||
b10dbbca | 1977 | moffsety = MEM_OFFSET (y); |
1978 | if (TREE_CODE (expry) == COMPONENT_REF) | |
1979 | { | |
1980 | tree t = decl_for_component_ref (expry); | |
1981 | if (! t) | |
1982 | return 0; | |
1983 | moffsety = adjust_offset_for_component_ref (expry, moffsety); | |
1984 | expry = t; | |
1985 | } | |
2d8fe5d0 | 1986 | else if (TREE_CODE (expry) == INDIRECT_REF) |
1987 | { | |
1988 | expry = TREE_OPERAND (expry, 0); | |
1989 | if (flag_argument_noalias < 2 | |
1990 | || TREE_CODE (expry) != PARM_DECL) | |
1991 | return 0; | |
1992 | } | |
b10dbbca | 1993 | |
1994 | if (! DECL_P (exprx) || ! DECL_P (expry)) | |
ddb3d16f | 1995 | return 0; |
1996 | ||
b10dbbca | 1997 | rtlx = DECL_RTL (exprx); |
1998 | rtly = DECL_RTL (expry); | |
ddb3d16f | 1999 | |
10e949c1 | 2000 | /* If either RTL is not a MEM, it must be a REG or CONCAT, meaning they |
2001 | can't overlap unless they are the same because we never reuse that part | |
2002 | of the stack frame used for locals for spilled pseudos. */ | |
2003 | if ((GET_CODE (rtlx) != MEM || GET_CODE (rtly) != MEM) | |
2004 | && ! rtx_equal_p (rtlx, rtly)) | |
ddb3d16f | 2005 | return 1; |
2006 | ||
2007 | /* Get the base and offsets of both decls. If either is a register, we | |
2008 | know both are and are the same, so use that as the base. The only | |
2009 | we can avoid overlap is if we can deduce that they are nonoverlapping | |
2010 | pieces of that decl, which is very rare. */ | |
10e949c1 | 2011 | basex = GET_CODE (rtlx) == MEM ? XEXP (rtlx, 0) : rtlx; |
ddb3d16f | 2012 | if (GET_CODE (basex) == PLUS && GET_CODE (XEXP (basex, 1)) == CONST_INT) |
2013 | offsetx = INTVAL (XEXP (basex, 1)), basex = XEXP (basex, 0); | |
2014 | ||
10e949c1 | 2015 | basey = GET_CODE (rtly) == MEM ? XEXP (rtly, 0) : rtly; |
ddb3d16f | 2016 | if (GET_CODE (basey) == PLUS && GET_CODE (XEXP (basey, 1)) == CONST_INT) |
2017 | offsety = INTVAL (XEXP (basey, 1)), basey = XEXP (basey, 0); | |
2018 | ||
c9c48480 | 2019 | /* If the bases are different, we know they do not overlap if both |
9342ee68 | 2020 | are constants or if one is a constant and the other a pointer into the |
c9c48480 | 2021 | stack frame. Otherwise a different base means we can't tell if they |
2022 | overlap or not. */ | |
2023 | if (! rtx_equal_p (basex, basey)) | |
9342ee68 | 2024 | return ((CONSTANT_P (basex) && CONSTANT_P (basey)) |
2025 | || (CONSTANT_P (basex) && REG_P (basey) | |
2026 | && REGNO_PTR_FRAME_P (REGNO (basey))) | |
2027 | || (CONSTANT_P (basey) && REG_P (basex) | |
2028 | && REGNO_PTR_FRAME_P (REGNO (basex)))); | |
ddb3d16f | 2029 | |
b10dbbca | 2030 | sizex = (GET_CODE (rtlx) != MEM ? (int) GET_MODE_SIZE (GET_MODE (rtlx)) |
ddb3d16f | 2031 | : MEM_SIZE (rtlx) ? INTVAL (MEM_SIZE (rtlx)) |
2032 | : -1); | |
b10dbbca | 2033 | sizey = (GET_CODE (rtly) != MEM ? (int) GET_MODE_SIZE (GET_MODE (rtly)) |
ddb3d16f | 2034 | : MEM_SIZE (rtly) ? INTVAL (MEM_SIZE (rtly)) : |
2035 | -1); | |
2036 | ||
dc2dfdb6 | 2037 | /* If we have an offset for either memref, it can update the values computed |
2038 | above. */ | |
b10dbbca | 2039 | if (moffsetx) |
2040 | offsetx += INTVAL (moffsetx), sizex -= INTVAL (moffsetx); | |
2041 | if (moffsety) | |
2042 | offsety += INTVAL (moffsety), sizey -= INTVAL (moffsety); | |
ddb3d16f | 2043 | |
dc2dfdb6 | 2044 | /* If a memref has both a size and an offset, we can use the smaller size. |
203c9fee | 2045 | We can't do this if the offset isn't known because we must view this |
dc2dfdb6 | 2046 | memref as being anywhere inside the DECL's MEM. */ |
b10dbbca | 2047 | if (MEM_SIZE (x) && moffsetx) |
ddb3d16f | 2048 | sizex = INTVAL (MEM_SIZE (x)); |
b10dbbca | 2049 | if (MEM_SIZE (y) && moffsety) |
ddb3d16f | 2050 | sizey = INTVAL (MEM_SIZE (y)); |
2051 | ||
2052 | /* Put the values of the memref with the lower offset in X's values. */ | |
2053 | if (offsetx > offsety) | |
2054 | { | |
2055 | tem = offsetx, offsetx = offsety, offsety = tem; | |
2056 | tem = sizex, sizex = sizey, sizey = tem; | |
2057 | } | |
2058 | ||
2059 | /* If we don't know the size of the lower-offset value, we can't tell | |
2060 | if they conflict. Otherwise, we do the test. */ | |
906923ba | 2061 | return sizex >= 0 && offsety >= offsetx + sizex; |
ddb3d16f | 2062 | } |
2063 | ||
ea0cb7ae | 2064 | /* True dependence: X is read after store in MEM takes place. */ |
2065 | ||
2066 | int | |
2067 | true_dependence (mem, mem_mode, x, varies) | |
2068 | rtx mem; | |
2069 | enum machine_mode mem_mode; | |
2070 | rtx x; | |
ea087693 | 2071 | int (*varies) PARAMS ((rtx, int)); |
ea0cb7ae | 2072 | { |
19cb6b50 | 2073 | rtx x_addr, mem_addr; |
9ee7cac5 | 2074 | rtx base; |
ea0cb7ae | 2075 | |
2076 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) | |
2077 | return 1; | |
2078 | ||
a57f4c4d | 2079 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
2080 | This is used in epilogue deallocation functions. */ | |
2081 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) | |
2082 | return 1; | |
2083 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
2084 | return 1; | |
2085 | ||
b5ba9f3a | 2086 | if (DIFFERENT_ALIAS_SETS_P (x, mem)) |
2087 | return 0; | |
2088 | ||
15750b1e | 2089 | /* Unchanging memory can't conflict with non-unchanging memory. |
2090 | A non-unchanging read can conflict with a non-unchanging write. | |
2091 | An unchanging read can conflict with an unchanging write since | |
2092 | there may be a single store to this address to initialize it. | |
805acfa0 | 2093 | Note that an unchanging store can conflict with a non-unchanging read |
2094 | since we have to make conservative assumptions when we have a | |
2095 | record with readonly fields and we are copying the whole thing. | |
15750b1e | 2096 | Just fall through to the code below to resolve potential conflicts. |
2097 | This won't handle all cases optimally, but the possible performance | |
2098 | loss should be negligible. */ | |
805acfa0 | 2099 | if (RTX_UNCHANGING_P (x) && ! RTX_UNCHANGING_P (mem)) |
ea0cb7ae | 2100 | return 0; |
2101 | ||
ddb3d16f | 2102 | if (nonoverlapping_memrefs_p (mem, x)) |
2103 | return 0; | |
2104 | ||
9fb1c31b | 2105 | if (mem_mode == VOIDmode) |
2106 | mem_mode = GET_MODE (mem); | |
2107 | ||
1617c276 | 2108 | x_addr = get_addr (XEXP (x, 0)); |
2109 | mem_addr = get_addr (XEXP (mem, 0)); | |
2110 | ||
002fe3cb | 2111 | base = find_base_term (x_addr); |
2112 | if (base && (GET_CODE (base) == LABEL_REF | |
2113 | || (GET_CODE (base) == SYMBOL_REF | |
2114 | && CONSTANT_POOL_ADDRESS_P (base)))) | |
2115 | return 0; | |
2116 | ||
1617c276 | 2117 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), mem_mode)) |
3ad3a0ed | 2118 | return 0; |
2119 | ||
1617c276 | 2120 | x_addr = canon_rtx (x_addr); |
2121 | mem_addr = canon_rtx (mem_addr); | |
35d3eedd | 2122 | |
4958fe6e | 2123 | if (! memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr, |
2124 | SIZE_FOR_MODE (x), x_addr, 0)) | |
2125 | return 0; | |
2126 | ||
6a0934dd | 2127 | if (aliases_everything_p (x)) |
4958fe6e | 2128 | return 1; |
2129 | ||
35a3065a | 2130 | /* We cannot use aliases_everything_p to test MEM, since we must look |
6a0934dd | 2131 | at MEM_MODE, rather than GET_MODE (MEM). */ |
2132 | if (mem_mode == QImode || GET_CODE (mem_addr) == AND) | |
8e802be9 | 2133 | return 1; |
2134 | ||
2135 | /* In true_dependence we also allow BLKmode to alias anything. Why | |
2136 | don't we do this in anti_dependence and output_dependence? */ | |
2137 | if (mem_mode == BLKmode || GET_MODE (x) == BLKmode) | |
2138 | return 1; | |
2139 | ||
2140 | return ! fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, | |
2141 | varies); | |
2142 | } | |
2143 | ||
2144 | /* Canonical true dependence: X is read after store in MEM takes place. | |
9342ee68 | 2145 | Variant of true_dependence which assumes MEM has already been |
2146 | canonicalized (hence we no longer do that here). | |
2147 | The mem_addr argument has been added, since true_dependence computed | |
8e802be9 | 2148 | this value prior to canonicalizing. */ |
2149 | ||
2150 | int | |
2151 | canon_true_dependence (mem, mem_mode, mem_addr, x, varies) | |
2152 | rtx mem, mem_addr, x; | |
2153 | enum machine_mode mem_mode; | |
2154 | int (*varies) PARAMS ((rtx, int)); | |
2155 | { | |
19cb6b50 | 2156 | rtx x_addr; |
8e802be9 | 2157 | |
2158 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) | |
2159 | return 1; | |
2160 | ||
d7b592b0 | 2161 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
2162 | This is used in epilogue deallocation functions. */ | |
2163 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) | |
2164 | return 1; | |
2165 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
2166 | return 1; | |
2167 | ||
8e802be9 | 2168 | if (DIFFERENT_ALIAS_SETS_P (x, mem)) |
2169 | return 0; | |
2170 | ||
2171 | /* If X is an unchanging read, then it can't possibly conflict with any | |
2172 | non-unchanging store. It may conflict with an unchanging write though, | |
2173 | because there may be a single store to this address to initialize it. | |
2174 | Just fall through to the code below to resolve the case where we have | |
2175 | both an unchanging read and an unchanging write. This won't handle all | |
2176 | cases optimally, but the possible performance loss should be | |
2177 | negligible. */ | |
2178 | if (RTX_UNCHANGING_P (x) && ! RTX_UNCHANGING_P (mem)) | |
2179 | return 0; | |
2180 | ||
ddb3d16f | 2181 | if (nonoverlapping_memrefs_p (x, mem)) |
2182 | return 0; | |
2183 | ||
8e802be9 | 2184 | x_addr = get_addr (XEXP (x, 0)); |
2185 | ||
2186 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), mem_mode)) | |
2187 | return 0; | |
2188 | ||
2189 | x_addr = canon_rtx (x_addr); | |
2190 | if (! memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr, | |
2191 | SIZE_FOR_MODE (x), x_addr, 0)) | |
2192 | return 0; | |
2193 | ||
2194 | if (aliases_everything_p (x)) | |
2195 | return 1; | |
2196 | ||
35a3065a | 2197 | /* We cannot use aliases_everything_p to test MEM, since we must look |
8e802be9 | 2198 | at MEM_MODE, rather than GET_MODE (MEM). */ |
2199 | if (mem_mode == QImode || GET_CODE (mem_addr) == AND) | |
6a0934dd | 2200 | return 1; |
4958fe6e | 2201 | |
6a0934dd | 2202 | /* In true_dependence we also allow BLKmode to alias anything. Why |
2203 | don't we do this in anti_dependence and output_dependence? */ | |
2204 | if (mem_mode == BLKmode || GET_MODE (x) == BLKmode) | |
2205 | return 1; | |
4958fe6e | 2206 | |
1617c276 | 2207 | return ! fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, |
2208 | varies); | |
ea0cb7ae | 2209 | } |
2210 | ||
d10cfa8d | 2211 | /* Returns nonzero if a write to X might alias a previous read from |
2212 | (or, if WRITEP is nonzero, a write to) MEM. */ | |
ea0cb7ae | 2213 | |
fe69e4fe | 2214 | static int |
6a0934dd | 2215 | write_dependence_p (mem, x, writep) |
ea0cb7ae | 2216 | rtx mem; |
2217 | rtx x; | |
6a0934dd | 2218 | int writep; |
ea0cb7ae | 2219 | { |
35d3eedd | 2220 | rtx x_addr, mem_addr; |
6a0934dd | 2221 | rtx fixed_scalar; |
9ee7cac5 | 2222 | rtx base; |
35d3eedd | 2223 | |
ea0cb7ae | 2224 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) |
2225 | return 1; | |
2226 | ||
a57f4c4d | 2227 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
2228 | This is used in epilogue deallocation functions. */ | |
2229 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) | |
2230 | return 1; | |
2231 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
2232 | return 1; | |
2233 | ||
1617c276 | 2234 | if (DIFFERENT_ALIAS_SETS_P (x, mem)) |
2235 | return 0; | |
2236 | ||
15750b1e | 2237 | /* Unchanging memory can't conflict with non-unchanging memory. */ |
2238 | if (RTX_UNCHANGING_P (x) != RTX_UNCHANGING_P (mem)) | |
2239 | return 0; | |
2240 | ||
ea0cb7ae | 2241 | /* If MEM is an unchanging read, then it can't possibly conflict with |
2242 | the store to X, because there is at most one store to MEM, and it must | |
2243 | have occurred somewhere before MEM. */ | |
002fe3cb | 2244 | if (! writep && RTX_UNCHANGING_P (mem)) |
2245 | return 0; | |
2246 | ||
ddb3d16f | 2247 | if (nonoverlapping_memrefs_p (x, mem)) |
2248 | return 0; | |
2249 | ||
002fe3cb | 2250 | x_addr = get_addr (XEXP (x, 0)); |
2251 | mem_addr = get_addr (XEXP (mem, 0)); | |
2252 | ||
9ee7cac5 | 2253 | if (! writep) |
2254 | { | |
002fe3cb | 2255 | base = find_base_term (mem_addr); |
9ee7cac5 | 2256 | if (base && (GET_CODE (base) == LABEL_REF |
2257 | || (GET_CODE (base) == SYMBOL_REF | |
2258 | && CONSTANT_POOL_ADDRESS_P (base)))) | |
2259 | return 0; | |
2260 | } | |
2261 | ||
1617c276 | 2262 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), |
2263 | GET_MODE (mem))) | |
b5ba9f3a | 2264 | return 0; |
2265 | ||
1617c276 | 2266 | x_addr = canon_rtx (x_addr); |
2267 | mem_addr = canon_rtx (mem_addr); | |
35d3eedd | 2268 | |
6a0934dd | 2269 | if (!memrefs_conflict_p (SIZE_FOR_MODE (mem), mem_addr, |
2270 | SIZE_FOR_MODE (x), x_addr, 0)) | |
2271 | return 0; | |
2272 | ||
9342ee68 | 2273 | fixed_scalar |
1617c276 | 2274 | = fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, |
2275 | rtx_addr_varies_p); | |
2276 | ||
6a0934dd | 2277 | return (!(fixed_scalar == mem && !aliases_everything_p (x)) |
2278 | && !(fixed_scalar == x && !aliases_everything_p (mem))); | |
2279 | } | |
2280 | ||
2281 | /* Anti dependence: X is written after read in MEM takes place. */ | |
2282 | ||
2283 | int | |
2284 | anti_dependence (mem, x) | |
2285 | rtx mem; | |
2286 | rtx x; | |
2287 | { | |
2288 | return write_dependence_p (mem, x, /*writep=*/0); | |
ea0cb7ae | 2289 | } |
2290 | ||
2291 | /* Output dependence: X is written after store in MEM takes place. */ | |
2292 | ||
2293 | int | |
2294 | output_dependence (mem, x) | |
19cb6b50 | 2295 | rtx mem; |
2296 | rtx x; | |
ea0cb7ae | 2297 | { |
6a0934dd | 2298 | return write_dependence_p (mem, x, /*writep=*/1); |
ea0cb7ae | 2299 | } |
c352cbc7 | 2300 | \f |
2301 | /* A subroutine of nonlocal_mentioned_p, returns 1 if *LOC mentions | |
2302 | something which is not local to the function and is not constant. */ | |
142131ed | 2303 | |
2304 | static int | |
c352cbc7 | 2305 | nonlocal_mentioned_p_1 (loc, data) |
2306 | rtx *loc; | |
2307 | void *data ATTRIBUTE_UNUSED; | |
142131ed | 2308 | { |
c352cbc7 | 2309 | rtx x = *loc; |
142131ed | 2310 | rtx base; |
142131ed | 2311 | int regno; |
2312 | ||
c352cbc7 | 2313 | if (! x) |
2314 | return 0; | |
142131ed | 2315 | |
c352cbc7 | 2316 | switch (GET_CODE (x)) |
142131ed | 2317 | { |
2318 | case SUBREG: | |
2319 | if (GET_CODE (SUBREG_REG (x)) == REG) | |
2320 | { | |
2321 | /* Global registers are not local. */ | |
2322 | if (REGNO (SUBREG_REG (x)) < FIRST_PSEUDO_REGISTER | |
701e46d0 | 2323 | && global_regs[subreg_regno (x)]) |
142131ed | 2324 | return 1; |
2325 | return 0; | |
2326 | } | |
2327 | break; | |
2328 | ||
2329 | case REG: | |
2330 | regno = REGNO (x); | |
2331 | /* Global registers are not local. */ | |
2332 | if (regno < FIRST_PSEUDO_REGISTER && global_regs[regno]) | |
2333 | return 1; | |
2334 | return 0; | |
2335 | ||
2336 | case SCRATCH: | |
2337 | case PC: | |
2338 | case CC0: | |
2339 | case CONST_INT: | |
2340 | case CONST_DOUBLE: | |
886cfd4f | 2341 | case CONST_VECTOR: |
142131ed | 2342 | case CONST: |
2343 | case LABEL_REF: | |
2344 | return 0; | |
2345 | ||
2346 | case SYMBOL_REF: | |
2347 | /* Constants in the function's constants pool are constant. */ | |
2348 | if (CONSTANT_POOL_ADDRESS_P (x)) | |
2349 | return 0; | |
2350 | return 1; | |
2351 | ||
2352 | case CALL: | |
1addbe73 | 2353 | /* Non-constant calls and recursion are not local. */ |
142131ed | 2354 | return 1; |
2355 | ||
2356 | case MEM: | |
2357 | /* Be overly conservative and consider any volatile memory | |
2358 | reference as not local. */ | |
2359 | if (MEM_VOLATILE_P (x)) | |
2360 | return 1; | |
2361 | base = find_base_term (XEXP (x, 0)); | |
2362 | if (base) | |
2363 | { | |
3a935f06 | 2364 | /* A Pmode ADDRESS could be a reference via the structure value |
2365 | address or static chain. Such memory references are nonlocal. | |
2366 | ||
2367 | Thus, we have to examine the contents of the ADDRESS to find | |
2368 | out if this is a local reference or not. */ | |
2369 | if (GET_CODE (base) == ADDRESS | |
2370 | && GET_MODE (base) == Pmode | |
2371 | && (XEXP (base, 0) == stack_pointer_rtx | |
2372 | || XEXP (base, 0) == arg_pointer_rtx | |
2373 | #if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM | |
2374 | || XEXP (base, 0) == hard_frame_pointer_rtx | |
2375 | #endif | |
2376 | || XEXP (base, 0) == frame_pointer_rtx)) | |
142131ed | 2377 | return 0; |
2378 | /* Constants in the function's constant pool are constant. */ | |
2379 | if (GET_CODE (base) == SYMBOL_REF && CONSTANT_POOL_ADDRESS_P (base)) | |
2380 | return 0; | |
2381 | } | |
2382 | return 1; | |
2383 | ||
1addbe73 | 2384 | case UNSPEC_VOLATILE: |
142131ed | 2385 | case ASM_INPUT: |
142131ed | 2386 | return 1; |
2387 | ||
1addbe73 | 2388 | case ASM_OPERANDS: |
2389 | if (MEM_VOLATILE_P (x)) | |
2390 | return 1; | |
2391 | ||
2392 | /* FALLTHROUGH */ | |
2393 | ||
142131ed | 2394 | default: |
2395 | break; | |
2396 | } | |
2397 | ||
c352cbc7 | 2398 | return 0; |
2399 | } | |
2400 | ||
d10cfa8d | 2401 | /* Returns nonzero if X might mention something which is not |
c352cbc7 | 2402 | local to the function and is not constant. */ |
142131ed | 2403 | |
c352cbc7 | 2404 | static int |
2405 | nonlocal_mentioned_p (x) | |
2406 | rtx x; | |
2407 | { | |
2408 | ||
2409 | if (INSN_P (x)) | |
2410 | { | |
2411 | if (GET_CODE (x) == CALL_INSN) | |
2412 | { | |
2413 | if (! CONST_OR_PURE_CALL_P (x)) | |
2414 | return 1; | |
2415 | x = CALL_INSN_FUNCTION_USAGE (x); | |
2416 | if (x == 0) | |
2417 | return 0; | |
9342ee68 | 2418 | } |
c352cbc7 | 2419 | else |
9342ee68 | 2420 | x = PATTERN (x); |
c352cbc7 | 2421 | } |
2422 | ||
2423 | return for_each_rtx (&x, nonlocal_mentioned_p_1, NULL); | |
2424 | } | |
2425 | ||
2426 | /* A subroutine of nonlocal_referenced_p, returns 1 if *LOC references | |
2427 | something which is not local to the function and is not constant. */ | |
2428 | ||
2429 | static int | |
2430 | nonlocal_referenced_p_1 (loc, data) | |
2431 | rtx *loc; | |
2432 | void *data ATTRIBUTE_UNUSED; | |
2433 | { | |
2434 | rtx x = *loc; | |
2435 | ||
2436 | if (! x) | |
2437 | return 0; | |
2438 | ||
2439 | switch (GET_CODE (x)) | |
2440 | { | |
2441 | case MEM: | |
2442 | case REG: | |
2443 | case SYMBOL_REF: | |
2444 | case SUBREG: | |
2445 | return nonlocal_mentioned_p (x); | |
2446 | ||
2447 | case CALL: | |
2448 | /* Non-constant calls and recursion are not local. */ | |
2449 | return 1; | |
2450 | ||
2451 | case SET: | |
2452 | if (nonlocal_mentioned_p (SET_SRC (x))) | |
2453 | return 1; | |
2454 | ||
2455 | if (GET_CODE (SET_DEST (x)) == MEM) | |
2456 | return nonlocal_mentioned_p (XEXP (SET_DEST (x), 0)); | |
2457 | ||
2458 | /* If the destination is anything other than a CC0, PC, | |
2459 | MEM, REG, or a SUBREG of a REG that occupies all of | |
2460 | the REG, then X references nonlocal memory if it is | |
2461 | mentioned in the destination. */ | |
2462 | if (GET_CODE (SET_DEST (x)) != CC0 | |
2463 | && GET_CODE (SET_DEST (x)) != PC | |
2464 | && GET_CODE (SET_DEST (x)) != REG | |
2465 | && ! (GET_CODE (SET_DEST (x)) == SUBREG | |
2466 | && GET_CODE (SUBREG_REG (SET_DEST (x))) == REG | |
2467 | && (((GET_MODE_SIZE (GET_MODE (SUBREG_REG (SET_DEST (x)))) | |
2468 | + (UNITS_PER_WORD - 1)) / UNITS_PER_WORD) | |
2469 | == ((GET_MODE_SIZE (GET_MODE (SET_DEST (x))) | |
2470 | + (UNITS_PER_WORD - 1)) / UNITS_PER_WORD)))) | |
2471 | return nonlocal_mentioned_p (SET_DEST (x)); | |
2472 | return 0; | |
2473 | ||
2474 | case CLOBBER: | |
2475 | if (GET_CODE (XEXP (x, 0)) == MEM) | |
2476 | return nonlocal_mentioned_p (XEXP (XEXP (x, 0), 0)); | |
2477 | return 0; | |
2478 | ||
2479 | case USE: | |
2480 | return nonlocal_mentioned_p (XEXP (x, 0)); | |
2481 | ||
2482 | case ASM_INPUT: | |
2483 | case UNSPEC_VOLATILE: | |
2484 | return 1; | |
2485 | ||
2486 | case ASM_OPERANDS: | |
2487 | if (MEM_VOLATILE_P (x)) | |
2488 | return 1; | |
2489 | ||
2490 | /* FALLTHROUGH */ | |
2491 | ||
2492 | default: | |
2493 | break; | |
2494 | } | |
2495 | ||
2496 | return 0; | |
2497 | } | |
2498 | ||
d10cfa8d | 2499 | /* Returns nonzero if X might reference something which is not |
c352cbc7 | 2500 | local to the function and is not constant. */ |
2501 | ||
2502 | static int | |
2503 | nonlocal_referenced_p (x) | |
2504 | rtx x; | |
2505 | { | |
2506 | ||
2507 | if (INSN_P (x)) | |
2508 | { | |
2509 | if (GET_CODE (x) == CALL_INSN) | |
2510 | { | |
2511 | if (! CONST_OR_PURE_CALL_P (x)) | |
2512 | return 1; | |
2513 | x = CALL_INSN_FUNCTION_USAGE (x); | |
2514 | if (x == 0) | |
2515 | return 0; | |
9342ee68 | 2516 | } |
c352cbc7 | 2517 | else |
9342ee68 | 2518 | x = PATTERN (x); |
c352cbc7 | 2519 | } |
2520 | ||
2521 | return for_each_rtx (&x, nonlocal_referenced_p_1, NULL); | |
2522 | } | |
2523 | ||
2524 | /* A subroutine of nonlocal_set_p, returns 1 if *LOC sets | |
2525 | something which is not local to the function and is not constant. */ | |
2526 | ||
2527 | static int | |
2528 | nonlocal_set_p_1 (loc, data) | |
2529 | rtx *loc; | |
2530 | void *data ATTRIBUTE_UNUSED; | |
2531 | { | |
2532 | rtx x = *loc; | |
2533 | ||
2534 | if (! x) | |
2535 | return 0; | |
2536 | ||
2537 | switch (GET_CODE (x)) | |
2538 | { | |
2539 | case CALL: | |
2540 | /* Non-constant calls and recursion are not local. */ | |
2541 | return 1; | |
2542 | ||
2543 | case PRE_INC: | |
2544 | case PRE_DEC: | |
2545 | case POST_INC: | |
2546 | case POST_DEC: | |
2547 | case PRE_MODIFY: | |
2548 | case POST_MODIFY: | |
2549 | return nonlocal_mentioned_p (XEXP (x, 0)); | |
2550 | ||
2551 | case SET: | |
2552 | if (nonlocal_mentioned_p (SET_DEST (x))) | |
2553 | return 1; | |
2554 | return nonlocal_set_p (SET_SRC (x)); | |
2555 | ||
2556 | case CLOBBER: | |
2557 | return nonlocal_mentioned_p (XEXP (x, 0)); | |
2558 | ||
2559 | case USE: | |
2560 | return 0; | |
2561 | ||
2562 | case ASM_INPUT: | |
2563 | case UNSPEC_VOLATILE: | |
2564 | return 1; | |
2565 | ||
2566 | case ASM_OPERANDS: | |
2567 | if (MEM_VOLATILE_P (x)) | |
2568 | return 1; | |
2569 | ||
2570 | /* FALLTHROUGH */ | |
2571 | ||
2572 | default: | |
2573 | break; | |
2574 | } | |
142131ed | 2575 | |
2576 | return 0; | |
2577 | } | |
2578 | ||
d10cfa8d | 2579 | /* Returns nonzero if X might set something which is not |
c352cbc7 | 2580 | local to the function and is not constant. */ |
2581 | ||
2582 | static int | |
2583 | nonlocal_set_p (x) | |
2584 | rtx x; | |
2585 | { | |
2586 | ||
2587 | if (INSN_P (x)) | |
2588 | { | |
2589 | if (GET_CODE (x) == CALL_INSN) | |
2590 | { | |
2591 | if (! CONST_OR_PURE_CALL_P (x)) | |
2592 | return 1; | |
2593 | x = CALL_INSN_FUNCTION_USAGE (x); | |
2594 | if (x == 0) | |
2595 | return 0; | |
9342ee68 | 2596 | } |
c352cbc7 | 2597 | else |
9342ee68 | 2598 | x = PATTERN (x); |
c352cbc7 | 2599 | } |
2600 | ||
2601 | return for_each_rtx (&x, nonlocal_set_p_1, NULL); | |
2602 | } | |
2603 | ||
142131ed | 2604 | /* Mark the function if it is constant. */ |
2605 | ||
2606 | void | |
2607 | mark_constant_function () | |
2608 | { | |
2609 | rtx insn; | |
c352cbc7 | 2610 | int nonlocal_memory_referenced; |
142131ed | 2611 | |
4f8e9d5c | 2612 | if (TREE_READONLY (current_function_decl) |
1addbe73 | 2613 | || DECL_IS_PURE (current_function_decl) |
142131ed | 2614 | || TREE_THIS_VOLATILE (current_function_decl) |
c352cbc7 | 2615 | || TYPE_MODE (TREE_TYPE (current_function_decl)) == VOIDmode |
4f8e9d5c | 2616 | || current_function_has_nonlocal_goto |
2617 | || !(*targetm.binds_local_p) (current_function_decl)) | |
142131ed | 2618 | return; |
2619 | ||
080f162d | 2620 | /* A loop might not return which counts as a side effect. */ |
ecb7b891 | 2621 | if (mark_dfs_back_edges ()) |
080f162d | 2622 | return; |
2623 | ||
c352cbc7 | 2624 | nonlocal_memory_referenced = 0; |
1addbe73 | 2625 | |
2626 | init_alias_analysis (); | |
2627 | ||
c352cbc7 | 2628 | /* Determine if this is a constant or pure function. */ |
142131ed | 2629 | |
2630 | for (insn = get_insns (); insn; insn = NEXT_INSN (insn)) | |
c352cbc7 | 2631 | { |
2632 | if (! INSN_P (insn)) | |
2633 | continue; | |
1addbe73 | 2634 | |
c352cbc7 | 2635 | if (nonlocal_set_p (insn) || global_reg_mentioned_p (insn) |
2636 | || volatile_refs_p (PATTERN (insn))) | |
9342ee68 | 2637 | break; |
142131ed | 2638 | |
c352cbc7 | 2639 | if (! nonlocal_memory_referenced) |
2640 | nonlocal_memory_referenced = nonlocal_referenced_p (insn); | |
2641 | } | |
9342ee68 | 2642 | |
c352cbc7 | 2643 | end_alias_analysis (); |
9342ee68 | 2644 | |
142131ed | 2645 | /* Mark the function. */ |
9342ee68 | 2646 | |
c352cbc7 | 2647 | if (insn) |
2648 | ; | |
2649 | else if (nonlocal_memory_referenced) | |
2650 | DECL_IS_PURE (current_function_decl) = 1; | |
2651 | else | |
1addbe73 | 2652 | TREE_READONLY (current_function_decl) = 1; |
142131ed | 2653 | } |
c352cbc7 | 2654 | \f |
35d3eedd | 2655 | |
35d3eedd | 2656 | void |
2657 | init_alias_once () | |
2658 | { | |
19cb6b50 | 2659 | int i; |
35d3eedd | 2660 | |
2661 | #ifndef OUTGOING_REGNO | |
2662 | #define OUTGOING_REGNO(N) N | |
2663 | #endif | |
2664 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) | |
2665 | /* Check whether this register can hold an incoming pointer | |
2666 | argument. FUNCTION_ARG_REGNO_P tests outgoing register | |
2c0e001b | 2667 | numbers, so translate if necessary due to register windows. */ |
35d3eedd | 2668 | if (FUNCTION_ARG_REGNO_P (OUTGOING_REGNO (i)) |
2669 | && HARD_REGNO_MODE_OK (i, Pmode)) | |
0c7f5242 | 2670 | static_reg_base_value[i] |
2671 | = gen_rtx_ADDRESS (VOIDmode, gen_rtx_REG (Pmode, i)); | |
2672 | ||
0c7f5242 | 2673 | static_reg_base_value[STACK_POINTER_REGNUM] |
2674 | = gen_rtx_ADDRESS (Pmode, stack_pointer_rtx); | |
2675 | static_reg_base_value[ARG_POINTER_REGNUM] | |
2676 | = gen_rtx_ADDRESS (Pmode, arg_pointer_rtx); | |
2677 | static_reg_base_value[FRAME_POINTER_REGNUM] | |
2678 | = gen_rtx_ADDRESS (Pmode, frame_pointer_rtx); | |
2679 | #if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM | |
2680 | static_reg_base_value[HARD_FRAME_POINTER_REGNUM] | |
2681 | = gen_rtx_ADDRESS (Pmode, hard_frame_pointer_rtx); | |
2682 | #endif | |
e26fd9bc | 2683 | |
2684 | alias_sets = splay_tree_new (splay_tree_compare_ints, 0, 0); | |
0c7f5242 | 2685 | } |
2686 | ||
73f5c1e3 | 2687 | /* Initialize the aliasing machinery. Initialize the REG_KNOWN_VALUE |
2688 | array. */ | |
2689 | ||
ea0cb7ae | 2690 | void |
2691 | init_alias_analysis () | |
2692 | { | |
2693 | int maxreg = max_reg_num (); | |
37b864db | 2694 | int changed, pass; |
19cb6b50 | 2695 | int i; |
2696 | unsigned int ui; | |
2697 | rtx insn; | |
ea0cb7ae | 2698 | |
2699 | reg_known_value_size = maxreg; | |
2700 | ||
9342ee68 | 2701 | reg_known_value |
7098ef4a | 2702 | = (rtx *) xcalloc ((maxreg - FIRST_PSEUDO_REGISTER), sizeof (rtx)) |
2703 | - FIRST_PSEUDO_REGISTER; | |
9342ee68 | 2704 | reg_known_equiv_p |
7098ef4a | 2705 | = (char*) xcalloc ((maxreg - FIRST_PSEUDO_REGISTER), sizeof (char)) |
ea0cb7ae | 2706 | - FIRST_PSEUDO_REGISTER; |
ea0cb7ae | 2707 | |
35d3eedd | 2708 | /* Overallocate reg_base_value to allow some growth during loop |
2709 | optimization. Loop unrolling can create a large number of | |
2710 | registers. */ | |
2711 | reg_base_value_size = maxreg * 2; | |
1f3233d1 | 2712 | reg_base_value = (rtx *) ggc_alloc_cleared (reg_base_value_size |
2713 | * sizeof (rtx)); | |
c2e94b25 | 2714 | |
7098ef4a | 2715 | new_reg_base_value = (rtx *) xmalloc (reg_base_value_size * sizeof (rtx)); |
2716 | reg_seen = (char *) xmalloc (reg_base_value_size); | |
1a6c3add | 2717 | if (! reload_completed && flag_unroll_loops) |
2718 | { | |
c2e94b25 | 2719 | /* ??? Why are we realloc'ing if we're just going to zero it? */ |
1a6c3add | 2720 | alias_invariant = (rtx *)xrealloc (alias_invariant, |
2721 | reg_base_value_size * sizeof (rtx)); | |
93d3b7de | 2722 | memset ((char *)alias_invariant, 0, reg_base_value_size * sizeof (rtx)); |
1a6c3add | 2723 | } |
06c5c535 | 2724 | |
2725 | /* The basic idea is that each pass through this loop will use the | |
2726 | "constant" information from the previous pass to propagate alias | |
2727 | information through another level of assignments. | |
2728 | ||
2729 | This could get expensive if the assignment chains are long. Maybe | |
2730 | we should throttle the number of iterations, possibly based on | |
35d3eedd | 2731 | the optimization level or flag_expensive_optimizations. |
06c5c535 | 2732 | |
2733 | We could propagate more information in the first pass by making use | |
2734 | of REG_N_SETS to determine immediately that the alias information | |
37b864db | 2735 | for a pseudo is "constant". |
2736 | ||
2737 | A program with an uninitialized variable can cause an infinite loop | |
2738 | here. Instead of doing a full dataflow analysis to detect such problems | |
2739 | we just cap the number of iterations for the loop. | |
2740 | ||
2741 | The state of the arrays for the set chain in question does not matter | |
2742 | since the program has undefined behavior. */ | |
35d3eedd | 2743 | |
37b864db | 2744 | pass = 0; |
35d3eedd | 2745 | do |
06c5c535 | 2746 | { |
2747 | /* Assume nothing will change this iteration of the loop. */ | |
2748 | changed = 0; | |
2749 | ||
06c5c535 | 2750 | /* We want to assign the same IDs each iteration of this loop, so |
2751 | start counting from zero each iteration of the loop. */ | |
2752 | unique_id = 0; | |
2753 | ||
35a3065a | 2754 | /* We're at the start of the function each iteration through the |
06c5c535 | 2755 | loop, so we're copying arguments. */ |
e5be0cc6 | 2756 | copying_arguments = true; |
ea0cb7ae | 2757 | |
35d3eedd | 2758 | /* Wipe the potential alias information clean for this pass. */ |
93d3b7de | 2759 | memset ((char *) new_reg_base_value, 0, reg_base_value_size * sizeof (rtx)); |
f0ad0992 | 2760 | |
35d3eedd | 2761 | /* Wipe the reg_seen array clean. */ |
93d3b7de | 2762 | memset ((char *) reg_seen, 0, reg_base_value_size); |
ea0cb7ae | 2763 | |
35d3eedd | 2764 | /* Mark all hard registers which may contain an address. |
2765 | The stack, frame and argument pointers may contain an address. | |
2766 | An argument register which can hold a Pmode value may contain | |
2767 | an address even if it is not in BASE_REGS. | |
f0ad0992 | 2768 | |
35d3eedd | 2769 | The address expression is VOIDmode for an argument and |
2770 | Pmode for other registers. */ | |
2771 | ||
e26fd9bc | 2772 | memcpy (new_reg_base_value, static_reg_base_value, |
2773 | FIRST_PSEUDO_REGISTER * sizeof (rtx)); | |
35d3eedd | 2774 | |
06c5c535 | 2775 | /* Walk the insns adding values to the new_reg_base_value array. */ |
2776 | for (insn = get_insns (); insn; insn = NEXT_INSN (insn)) | |
ea0cb7ae | 2777 | { |
9204e736 | 2778 | if (INSN_P (insn)) |
06c5c535 | 2779 | { |
35d3eedd | 2780 | rtx note, set; |
d6cb6164 | 2781 | |
2782 | #if defined (HAVE_prologue) || defined (HAVE_epilogue) | |
35a3065a | 2783 | /* The prologue/epilogue insns are not threaded onto the |
fd037eda | 2784 | insn chain until after reload has completed. Thus, |
2785 | there is no sense wasting time checking if INSN is in | |
2786 | the prologue/epilogue until after reload has completed. */ | |
2787 | if (reload_completed | |
2788 | && prologue_epilogue_contains (insn)) | |
d6cb6164 | 2789 | continue; |
2790 | #endif | |
2791 | ||
06c5c535 | 2792 | /* If this insn has a noalias note, process it, Otherwise, |
2793 | scan for sets. A simple set will have no side effects | |
2c0e001b | 2794 | which could change the base value of any other register. */ |
35d3eedd | 2795 | |
06c5c535 | 2796 | if (GET_CODE (PATTERN (insn)) == SET |
d6cb6164 | 2797 | && REG_NOTES (insn) != 0 |
2798 | && find_reg_note (insn, REG_NOALIAS, NULL_RTX)) | |
ec8895d7 | 2799 | record_set (SET_DEST (PATTERN (insn)), NULL_RTX, NULL); |
06c5c535 | 2800 | else |
ec8895d7 | 2801 | note_stores (PATTERN (insn), record_set, NULL); |
35d3eedd | 2802 | |
2803 | set = single_set (insn); | |
2804 | ||
2805 | if (set != 0 | |
2806 | && GET_CODE (SET_DEST (set)) == REG | |
9db10305 | 2807 | && REGNO (SET_DEST (set)) >= FIRST_PSEUDO_REGISTER) |
35d3eedd | 2808 | { |
9db10305 | 2809 | unsigned int regno = REGNO (SET_DEST (set)); |
970c0c06 | 2810 | rtx src = SET_SRC (set); |
2811 | ||
2812 | if (REG_NOTES (insn) != 0 | |
2813 | && (((note = find_reg_note (insn, REG_EQUAL, 0)) != 0 | |
2814 | && REG_N_SETS (regno) == 1) | |
2815 | || (note = find_reg_note (insn, REG_EQUIV, NULL_RTX)) != 0) | |
2816 | && GET_CODE (XEXP (note, 0)) != EXPR_LIST | |
97fb4325 | 2817 | && ! rtx_varies_p (XEXP (note, 0), 1) |
970c0c06 | 2818 | && ! reg_overlap_mentioned_p (SET_DEST (set), XEXP (note, 0))) |
2819 | { | |
2820 | reg_known_value[regno] = XEXP (note, 0); | |
2821 | reg_known_equiv_p[regno] = REG_NOTE_KIND (note) == REG_EQUIV; | |
2822 | } | |
2823 | else if (REG_N_SETS (regno) == 1 | |
2824 | && GET_CODE (src) == PLUS | |
2825 | && GET_CODE (XEXP (src, 0)) == REG | |
9db10305 | 2826 | && REGNO (XEXP (src, 0)) >= FIRST_PSEUDO_REGISTER |
2827 | && (reg_known_value[REGNO (XEXP (src, 0))]) | |
970c0c06 | 2828 | && GET_CODE (XEXP (src, 1)) == CONST_INT) |
2829 | { | |
2830 | rtx op0 = XEXP (src, 0); | |
97fb4325 | 2831 | op0 = reg_known_value[REGNO (op0)]; |
970c0c06 | 2832 | reg_known_value[regno] |
b244d4c7 | 2833 | = plus_constant (op0, INTVAL (XEXP (src, 1))); |
970c0c06 | 2834 | reg_known_equiv_p[regno] = 0; |
2835 | } | |
2836 | else if (REG_N_SETS (regno) == 1 | |
2837 | && ! rtx_varies_p (src, 1)) | |
2838 | { | |
2839 | reg_known_value[regno] = src; | |
2840 | reg_known_equiv_p[regno] = 0; | |
2841 | } | |
35d3eedd | 2842 | } |
06c5c535 | 2843 | } |
2844 | else if (GET_CODE (insn) == NOTE | |
2845 | && NOTE_LINE_NUMBER (insn) == NOTE_INSN_FUNCTION_BEG) | |
e5be0cc6 | 2846 | copying_arguments = false; |
35d3eedd | 2847 | } |
06c5c535 | 2848 | |
35d3eedd | 2849 | /* Now propagate values from new_reg_base_value to reg_base_value. */ |
274c11d8 | 2850 | for (ui = 0; ui < reg_base_value_size; ui++) |
35d3eedd | 2851 | { |
274c11d8 | 2852 | if (new_reg_base_value[ui] |
2853 | && new_reg_base_value[ui] != reg_base_value[ui] | |
2854 | && ! rtx_equal_p (new_reg_base_value[ui], reg_base_value[ui])) | |
06c5c535 | 2855 | { |
274c11d8 | 2856 | reg_base_value[ui] = new_reg_base_value[ui]; |
35d3eedd | 2857 | changed = 1; |
06c5c535 | 2858 | } |
ea0cb7ae | 2859 | } |
ea0cb7ae | 2860 | } |
35d3eedd | 2861 | while (changed && ++pass < MAX_ALIAS_LOOP_PASSES); |
ea0cb7ae | 2862 | |
2863 | /* Fill in the remaining entries. */ | |
2864 | for (i = FIRST_PSEUDO_REGISTER; i < maxreg; i++) | |
2865 | if (reg_known_value[i] == 0) | |
2866 | reg_known_value[i] = regno_reg_rtx[i]; | |
2867 | ||
ea0cb7ae | 2868 | /* Simplify the reg_base_value array so that no register refers to |
2869 | another register, except to special registers indirectly through | |
2870 | ADDRESS expressions. | |
2871 | ||
2872 | In theory this loop can take as long as O(registers^2), but unless | |
2873 | there are very long dependency chains it will run in close to linear | |
37b864db | 2874 | time. |
2875 | ||
2876 | This loop may not be needed any longer now that the main loop does | |
2877 | a better job at propagating alias information. */ | |
2878 | pass = 0; | |
ea0cb7ae | 2879 | do |
2880 | { | |
2881 | changed = 0; | |
37b864db | 2882 | pass++; |
274c11d8 | 2883 | for (ui = 0; ui < reg_base_value_size; ui++) |
ea0cb7ae | 2884 | { |
274c11d8 | 2885 | rtx base = reg_base_value[ui]; |
ea0cb7ae | 2886 | if (base && GET_CODE (base) == REG) |
2887 | { | |
9db10305 | 2888 | unsigned int base_regno = REGNO (base); |
274c11d8 | 2889 | if (base_regno == ui) /* register set from itself */ |
2890 | reg_base_value[ui] = 0; | |
ea0cb7ae | 2891 | else |
274c11d8 | 2892 | reg_base_value[ui] = reg_base_value[base_regno]; |
ea0cb7ae | 2893 | changed = 1; |
2894 | } | |
2895 | } | |
2896 | } | |
37b864db | 2897 | while (changed && pass < MAX_ALIAS_LOOP_PASSES); |
ea0cb7ae | 2898 | |
7098ef4a | 2899 | /* Clean up. */ |
2900 | free (new_reg_base_value); | |
06c5c535 | 2901 | new_reg_base_value = 0; |
7098ef4a | 2902 | free (reg_seen); |
ea0cb7ae | 2903 | reg_seen = 0; |
2904 | } | |
2905 | ||
2906 | void | |
2907 | end_alias_analysis () | |
2908 | { | |
7098ef4a | 2909 | free (reg_known_value + FIRST_PSEUDO_REGISTER); |
ea0cb7ae | 2910 | reg_known_value = 0; |
c2e94b25 | 2911 | reg_known_value_size = 0; |
7098ef4a | 2912 | free (reg_known_equiv_p + FIRST_PSEUDO_REGISTER); |
2913 | reg_known_equiv_p = 0; | |
1f3233d1 | 2914 | reg_base_value = 0; |
ea0cb7ae | 2915 | reg_base_value_size = 0; |
1a6c3add | 2916 | if (alias_invariant) |
2917 | { | |
c2e94b25 | 2918 | free (alias_invariant); |
1a6c3add | 2919 | alias_invariant = 0; |
2920 | } | |
ea0cb7ae | 2921 | } |
1f3233d1 | 2922 | |
2923 | #include "gt-alias.h" |