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9ae8ffe7 | 1 | /* Alias analysis for GNU C |
6e24b709 | 2 | Copyright (C) 1997, 1998, 1999, 2000, 2001 Free Software Foundation, Inc. |
9ae8ffe7 JL |
3 | Contributed by John Carr (jfc@mit.edu). |
4 | ||
1322177d | 5 | This file is part of GCC. |
9ae8ffe7 | 6 | |
1322177d LB |
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. | |
9ae8ffe7 | 11 | |
1322177d LB |
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. | |
9ae8ffe7 JL |
16 | |
17 | You should have received a copy of the GNU General Public License | |
1322177d LB |
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. */ | |
9ae8ffe7 JL |
21 | |
22 | #include "config.h" | |
670ee920 | 23 | #include "system.h" |
9ae8ffe7 | 24 | #include "rtl.h" |
7790df19 | 25 | #include "tree.h" |
6baf1cc8 | 26 | #include "tm_p.h" |
49ad7cfa | 27 | #include "function.h" |
9ae8ffe7 JL |
28 | #include "expr.h" |
29 | #include "regs.h" | |
30 | #include "hard-reg-set.h" | |
e004f2f7 | 31 | #include "basic-block.h" |
9ae8ffe7 | 32 | #include "flags.h" |
264fac34 | 33 | #include "output.h" |
2e107e9e | 34 | #include "toplev.h" |
eab5c70a | 35 | #include "cselib.h" |
3932261a | 36 | #include "splay-tree.h" |
ac606739 | 37 | #include "ggc.h" |
d23c55c2 | 38 | #include "langhooks.h" |
3932261a MM |
39 | |
40 | /* The alias sets assigned to MEMs assist the back-end in determining | |
41 | which MEMs can alias which other MEMs. In general, two MEMs in | |
ac3d9668 RK |
42 | different alias sets cannot alias each other, with one important |
43 | exception. Consider something like: | |
3932261a MM |
44 | |
45 | struct S {int i; double d; }; | |
46 | ||
47 | a store to an `S' can alias something of either type `int' or type | |
48 | `double'. (However, a store to an `int' cannot alias a `double' | |
49 | and vice versa.) We indicate this via a tree structure that looks | |
50 | like: | |
51 | struct S | |
52 | / \ | |
53 | / \ | |
54 | |/_ _\| | |
55 | int double | |
56 | ||
ac3d9668 RK |
57 | (The arrows are directed and point downwards.) |
58 | In this situation we say the alias set for `struct S' is the | |
59 | `superset' and that those for `int' and `double' are `subsets'. | |
60 | ||
3bdf5ad1 RK |
61 | To see whether two alias sets can point to the same memory, we must |
62 | see if either alias set is a subset of the other. We need not trace | |
e3aafbad | 63 | past immediate descendents, however, since we propagate all |
3bdf5ad1 | 64 | grandchildren up one level. |
3932261a MM |
65 | |
66 | Alias set zero is implicitly a superset of all other alias sets. | |
67 | However, this is no actual entry for alias set zero. It is an | |
68 | error to attempt to explicitly construct a subset of zero. */ | |
69 | ||
d4b60170 RK |
70 | typedef struct alias_set_entry |
71 | { | |
3932261a | 72 | /* The alias set number, as stored in MEM_ALIAS_SET. */ |
3bdf5ad1 | 73 | HOST_WIDE_INT alias_set; |
3932261a MM |
74 | |
75 | /* The children of the alias set. These are not just the immediate | |
e3aafbad | 76 | children, but, in fact, all descendents. So, if we have: |
3932261a MM |
77 | |
78 | struct T { struct S s; float f; } | |
79 | ||
80 | continuing our example above, the children here will be all of | |
81 | `int', `double', `float', and `struct S'. */ | |
82 | splay_tree children; | |
2bf105ab RK |
83 | |
84 | /* Nonzero if would have a child of zero: this effectively makes this | |
85 | alias set the same as alias set zero. */ | |
86 | int has_zero_child; | |
d4b60170 | 87 | } *alias_set_entry; |
9ae8ffe7 | 88 | |
3d994c6b KG |
89 | static int rtx_equal_for_memref_p PARAMS ((rtx, rtx)); |
90 | static rtx find_symbolic_term PARAMS ((rtx)); | |
a13d4ebf | 91 | rtx get_addr PARAMS ((rtx)); |
3d994c6b KG |
92 | static int memrefs_conflict_p PARAMS ((int, rtx, int, rtx, |
93 | HOST_WIDE_INT)); | |
94 | static void record_set PARAMS ((rtx, rtx, void *)); | |
95 | static rtx find_base_term PARAMS ((rtx)); | |
96 | static int base_alias_check PARAMS ((rtx, rtx, enum machine_mode, | |
97 | enum machine_mode)); | |
98 | static rtx find_base_value PARAMS ((rtx)); | |
99 | static int mems_in_disjoint_alias_sets_p PARAMS ((rtx, rtx)); | |
100 | static int insert_subset_children PARAMS ((splay_tree_node, void*)); | |
738cc472 | 101 | static tree find_base_decl PARAMS ((tree)); |
3bdf5ad1 | 102 | static alias_set_entry get_alias_set_entry PARAMS ((HOST_WIDE_INT)); |
eab5c70a | 103 | static rtx fixed_scalar_and_varying_struct_p PARAMS ((rtx, rtx, rtx, rtx, |
e38fe8e0 | 104 | int (*) (rtx, int))); |
3d994c6b | 105 | static int aliases_everything_p PARAMS ((rtx)); |
998d7deb RH |
106 | static bool nonoverlapping_component_refs_p PARAMS ((tree, tree)); |
107 | static tree decl_for_component_ref PARAMS ((tree)); | |
108 | static rtx adjust_offset_for_component_ref PARAMS ((tree, rtx)); | |
a4311dfe | 109 | static int nonoverlapping_memrefs_p PARAMS ((rtx, rtx)); |
3d994c6b | 110 | static int write_dependence_p PARAMS ((rtx, rtx, int)); |
bf6d9fd7 | 111 | static int nonlocal_mentioned_p PARAMS ((rtx)); |
9ae8ffe7 JL |
112 | |
113 | /* Set up all info needed to perform alias analysis on memory references. */ | |
114 | ||
d4b60170 | 115 | /* Returns the size in bytes of the mode of X. */ |
9ae8ffe7 JL |
116 | #define SIZE_FOR_MODE(X) (GET_MODE_SIZE (GET_MODE (X))) |
117 | ||
41472af8 | 118 | /* Returns nonzero if MEM1 and MEM2 do not alias because they are in |
264fac34 MM |
119 | different alias sets. We ignore alias sets in functions making use |
120 | of variable arguments because the va_arg macros on some systems are | |
121 | not legal ANSI C. */ | |
122 | #define DIFFERENT_ALIAS_SETS_P(MEM1, MEM2) \ | |
3932261a | 123 | mems_in_disjoint_alias_sets_p (MEM1, MEM2) |
41472af8 | 124 | |
ea64ef27 | 125 | /* Cap the number of passes we make over the insns propagating alias |
ac3d9668 | 126 | information through set chains. 10 is a completely arbitrary choice. */ |
ea64ef27 JL |
127 | #define MAX_ALIAS_LOOP_PASSES 10 |
128 | ||
9ae8ffe7 JL |
129 | /* reg_base_value[N] gives an address to which register N is related. |
130 | If all sets after the first add or subtract to the current value | |
131 | or otherwise modify it so it does not point to a different top level | |
132 | object, reg_base_value[N] is equal to the address part of the source | |
2a2c8203 JC |
133 | of the first set. |
134 | ||
135 | A base address can be an ADDRESS, SYMBOL_REF, or LABEL_REF. ADDRESS | |
136 | expressions represent certain special values: function arguments and | |
b3b5ad95 JL |
137 | the stack, frame, and argument pointers. |
138 | ||
139 | The contents of an ADDRESS is not normally used, the mode of the | |
140 | ADDRESS determines whether the ADDRESS is a function argument or some | |
141 | other special value. Pointer equality, not rtx_equal_p, determines whether | |
142 | two ADDRESS expressions refer to the same base address. | |
143 | ||
144 | The only use of the contents of an ADDRESS is for determining if the | |
145 | current function performs nonlocal memory memory references for the | |
146 | purposes of marking the function as a constant function. */ | |
2a2c8203 | 147 | |
ac606739 GS |
148 | static rtx *reg_base_value; |
149 | static rtx *new_reg_base_value; | |
d4b60170 RK |
150 | static unsigned int reg_base_value_size; /* size of reg_base_value array */ |
151 | ||
9ae8ffe7 | 152 | #define REG_BASE_VALUE(X) \ |
fb6754f0 BS |
153 | (REGNO (X) < reg_base_value_size \ |
154 | ? reg_base_value[REGNO (X)] : 0) | |
9ae8ffe7 | 155 | |
de12be17 JC |
156 | /* Vector of known invariant relationships between registers. Set in |
157 | loop unrolling. Indexed by register number, if nonzero the value | |
158 | is an expression describing this register in terms of another. | |
159 | ||
160 | The length of this array is REG_BASE_VALUE_SIZE. | |
161 | ||
162 | Because this array contains only pseudo registers it has no effect | |
163 | after reload. */ | |
164 | static rtx *alias_invariant; | |
165 | ||
c13e8210 MM |
166 | /* Vector indexed by N giving the initial (unchanging) value known for |
167 | pseudo-register N. This array is initialized in | |
168 | init_alias_analysis, and does not change until end_alias_analysis | |
169 | is called. */ | |
9ae8ffe7 JL |
170 | rtx *reg_known_value; |
171 | ||
172 | /* Indicates number of valid entries in reg_known_value. */ | |
770ae6cc | 173 | static unsigned int reg_known_value_size; |
9ae8ffe7 JL |
174 | |
175 | /* Vector recording for each reg_known_value whether it is due to a | |
176 | REG_EQUIV note. Future passes (viz., reload) may replace the | |
177 | pseudo with the equivalent expression and so we account for the | |
ac3d9668 RK |
178 | dependences that would be introduced if that happens. |
179 | ||
180 | The REG_EQUIV notes created in assign_parms may mention the arg | |
181 | pointer, and there are explicit insns in the RTL that modify the | |
182 | arg pointer. Thus we must ensure that such insns don't get | |
183 | scheduled across each other because that would invalidate the | |
184 | REG_EQUIV notes. One could argue that the REG_EQUIV notes are | |
185 | wrong, but solving the problem in the scheduler will likely give | |
186 | better code, so we do it here. */ | |
9ae8ffe7 JL |
187 | char *reg_known_equiv_p; |
188 | ||
2a2c8203 JC |
189 | /* True when scanning insns from the start of the rtl to the |
190 | NOTE_INSN_FUNCTION_BEG note. */ | |
9ae8ffe7 JL |
191 | static int copying_arguments; |
192 | ||
3932261a | 193 | /* The splay-tree used to store the various alias set entries. */ |
3932261a | 194 | static splay_tree alias_sets; |
ac3d9668 | 195 | \f |
3932261a MM |
196 | /* Returns a pointer to the alias set entry for ALIAS_SET, if there is |
197 | such an entry, or NULL otherwise. */ | |
198 | ||
199 | static alias_set_entry | |
200 | get_alias_set_entry (alias_set) | |
3bdf5ad1 | 201 | HOST_WIDE_INT alias_set; |
3932261a | 202 | { |
d4b60170 RK |
203 | splay_tree_node sn |
204 | = splay_tree_lookup (alias_sets, (splay_tree_key) alias_set); | |
3932261a | 205 | |
d4b60170 | 206 | return sn != 0 ? ((alias_set_entry) sn->value) : 0; |
3932261a MM |
207 | } |
208 | ||
ac3d9668 RK |
209 | /* Returns nonzero if the alias sets for MEM1 and MEM2 are such that |
210 | the two MEMs cannot alias each other. */ | |
3932261a MM |
211 | |
212 | static int | |
213 | mems_in_disjoint_alias_sets_p (mem1, mem2) | |
214 | rtx mem1; | |
215 | rtx mem2; | |
216 | { | |
3932261a MM |
217 | #ifdef ENABLE_CHECKING |
218 | /* Perform a basic sanity check. Namely, that there are no alias sets | |
219 | if we're not using strict aliasing. This helps to catch bugs | |
220 | whereby someone uses PUT_CODE, but doesn't clear MEM_ALIAS_SET, or | |
221 | where a MEM is allocated in some way other than by the use of | |
222 | gen_rtx_MEM, and the MEM_ALIAS_SET is not cleared. If we begin to | |
223 | use alias sets to indicate that spilled registers cannot alias each | |
224 | other, we might need to remove this check. */ | |
d4b60170 RK |
225 | if (! flag_strict_aliasing |
226 | && (MEM_ALIAS_SET (mem1) != 0 || MEM_ALIAS_SET (mem2) != 0)) | |
3932261a MM |
227 | abort (); |
228 | #endif | |
229 | ||
1da68f56 RK |
230 | return ! alias_sets_conflict_p (MEM_ALIAS_SET (mem1), MEM_ALIAS_SET (mem2)); |
231 | } | |
3932261a | 232 | |
1da68f56 RK |
233 | /* Insert the NODE into the splay tree given by DATA. Used by |
234 | record_alias_subset via splay_tree_foreach. */ | |
235 | ||
236 | static int | |
237 | insert_subset_children (node, data) | |
238 | splay_tree_node node; | |
239 | void *data; | |
240 | { | |
241 | splay_tree_insert ((splay_tree) data, node->key, node->value); | |
242 | ||
243 | return 0; | |
244 | } | |
245 | ||
246 | /* Return 1 if the two specified alias sets may conflict. */ | |
247 | ||
248 | int | |
249 | alias_sets_conflict_p (set1, set2) | |
250 | HOST_WIDE_INT set1, set2; | |
251 | { | |
252 | alias_set_entry ase; | |
253 | ||
254 | /* If have no alias set information for one of the operands, we have | |
255 | to assume it can alias anything. */ | |
256 | if (set1 == 0 || set2 == 0 | |
257 | /* If the two alias sets are the same, they may alias. */ | |
258 | || set1 == set2) | |
259 | return 1; | |
3932261a | 260 | |
3bdf5ad1 | 261 | /* See if the first alias set is a subset of the second. */ |
1da68f56 | 262 | ase = get_alias_set_entry (set1); |
2bf105ab RK |
263 | if (ase != 0 |
264 | && (ase->has_zero_child | |
265 | || splay_tree_lookup (ase->children, | |
1da68f56 RK |
266 | (splay_tree_key) set2))) |
267 | return 1; | |
3932261a MM |
268 | |
269 | /* Now do the same, but with the alias sets reversed. */ | |
1da68f56 | 270 | ase = get_alias_set_entry (set2); |
2bf105ab RK |
271 | if (ase != 0 |
272 | && (ase->has_zero_child | |
273 | || splay_tree_lookup (ase->children, | |
1da68f56 RK |
274 | (splay_tree_key) set1))) |
275 | return 1; | |
3932261a | 276 | |
1da68f56 | 277 | /* The two alias sets are distinct and neither one is the |
3932261a | 278 | child of the other. Therefore, they cannot alias. */ |
1da68f56 | 279 | return 0; |
3932261a | 280 | } |
1da68f56 RK |
281 | \f |
282 | /* Return 1 if TYPE is a RECORD_TYPE, UNION_TYPE, or QUAL_UNION_TYPE and has | |
283 | has any readonly fields. If any of the fields have types that | |
284 | contain readonly fields, return true as well. */ | |
3932261a | 285 | |
1da68f56 RK |
286 | int |
287 | readonly_fields_p (type) | |
288 | tree type; | |
3932261a | 289 | { |
1da68f56 RK |
290 | tree field; |
291 | ||
292 | if (TREE_CODE (type) != RECORD_TYPE && TREE_CODE (type) != UNION_TYPE | |
293 | && TREE_CODE (type) != QUAL_UNION_TYPE) | |
294 | return 0; | |
295 | ||
296 | for (field = TYPE_FIELDS (type); field != 0; field = TREE_CHAIN (field)) | |
297 | if (TREE_CODE (field) == FIELD_DECL | |
298 | && (TREE_READONLY (field) | |
299 | || readonly_fields_p (TREE_TYPE (field)))) | |
300 | return 1; | |
3932261a MM |
301 | |
302 | return 0; | |
303 | } | |
3bdf5ad1 | 304 | \f |
1da68f56 RK |
305 | /* Return 1 if any MEM object of type T1 will always conflict (using the |
306 | dependency routines in this file) with any MEM object of type T2. | |
307 | This is used when allocating temporary storage. If T1 and/or T2 are | |
308 | NULL_TREE, it means we know nothing about the storage. */ | |
309 | ||
310 | int | |
311 | objects_must_conflict_p (t1, t2) | |
312 | tree t1, t2; | |
313 | { | |
e8ea2809 RK |
314 | /* If neither has a type specified, we don't know if they'll conflict |
315 | because we may be using them to store objects of various types, for | |
316 | example the argument and local variables areas of inlined functions. */ | |
981a4c34 | 317 | if (t1 == 0 && t2 == 0) |
e8ea2809 RK |
318 | return 0; |
319 | ||
66cce54d RH |
320 | /* If one or the other has readonly fields or is readonly, |
321 | then they may not conflict. */ | |
322 | if ((t1 != 0 && readonly_fields_p (t1)) | |
323 | || (t2 != 0 && readonly_fields_p (t2)) | |
324 | || (t1 != 0 && TYPE_READONLY (t1)) | |
325 | || (t2 != 0 && TYPE_READONLY (t2))) | |
326 | return 0; | |
327 | ||
1da68f56 RK |
328 | /* If they are the same type, they must conflict. */ |
329 | if (t1 == t2 | |
330 | /* Likewise if both are volatile. */ | |
331 | || (t1 != 0 && TYPE_VOLATILE (t1) && t2 != 0 && TYPE_VOLATILE (t2))) | |
332 | return 1; | |
333 | ||
66cce54d RH |
334 | /* If one is aggregate and the other is scalar then they may not |
335 | conflict. */ | |
336 | if ((t1 != 0 && AGGREGATE_TYPE_P (t1)) | |
337 | != (t2 != 0 && AGGREGATE_TYPE_P (t2))) | |
1da68f56 RK |
338 | return 0; |
339 | ||
ec5c56db | 340 | /* Otherwise they conflict only if the alias sets conflict. */ |
1da68f56 RK |
341 | return alias_sets_conflict_p (t1 ? get_alias_set (t1) : 0, |
342 | t2 ? get_alias_set (t2) : 0); | |
343 | } | |
344 | \f | |
3bdf5ad1 RK |
345 | /* T is an expression with pointer type. Find the DECL on which this |
346 | expression is based. (For example, in `a[i]' this would be `a'.) | |
347 | If there is no such DECL, or a unique decl cannot be determined, | |
f5143c46 | 348 | NULL_TREE is returned. */ |
3bdf5ad1 RK |
349 | |
350 | static tree | |
351 | find_base_decl (t) | |
352 | tree t; | |
353 | { | |
354 | tree d0, d1, d2; | |
355 | ||
356 | if (t == 0 || t == error_mark_node || ! POINTER_TYPE_P (TREE_TYPE (t))) | |
357 | return 0; | |
358 | ||
359 | /* If this is a declaration, return it. */ | |
360 | if (TREE_CODE_CLASS (TREE_CODE (t)) == 'd') | |
361 | return t; | |
362 | ||
363 | /* Handle general expressions. It would be nice to deal with | |
364 | COMPONENT_REFs here. If we could tell that `a' and `b' were the | |
365 | same, then `a->f' and `b->f' are also the same. */ | |
366 | switch (TREE_CODE_CLASS (TREE_CODE (t))) | |
367 | { | |
368 | case '1': | |
369 | return find_base_decl (TREE_OPERAND (t, 0)); | |
370 | ||
371 | case '2': | |
372 | /* Return 0 if found in neither or both are the same. */ | |
373 | d0 = find_base_decl (TREE_OPERAND (t, 0)); | |
374 | d1 = find_base_decl (TREE_OPERAND (t, 1)); | |
375 | if (d0 == d1) | |
376 | return d0; | |
377 | else if (d0 == 0) | |
378 | return d1; | |
379 | else if (d1 == 0) | |
380 | return d0; | |
381 | else | |
382 | return 0; | |
383 | ||
384 | case '3': | |
385 | d0 = find_base_decl (TREE_OPERAND (t, 0)); | |
386 | d1 = find_base_decl (TREE_OPERAND (t, 1)); | |
3bdf5ad1 RK |
387 | d2 = find_base_decl (TREE_OPERAND (t, 2)); |
388 | ||
389 | /* Set any nonzero values from the last, then from the first. */ | |
390 | if (d1 == 0) d1 = d2; | |
391 | if (d0 == 0) d0 = d1; | |
392 | if (d1 == 0) d1 = d0; | |
393 | if (d2 == 0) d2 = d1; | |
394 | ||
395 | /* At this point all are nonzero or all are zero. If all three are the | |
396 | same, return it. Otherwise, return zero. */ | |
397 | return (d0 == d1 && d1 == d2) ? d0 : 0; | |
398 | ||
399 | default: | |
400 | return 0; | |
401 | } | |
402 | } | |
403 | ||
6e24b709 RK |
404 | /* Return 1 if all the nested component references handled by |
405 | get_inner_reference in T are such that we can address the object in T. */ | |
406 | ||
10b76d73 | 407 | int |
6e24b709 RK |
408 | can_address_p (t) |
409 | tree t; | |
410 | { | |
411 | /* If we're at the end, it is vacuously addressable. */ | |
412 | if (! handled_component_p (t)) | |
413 | return 1; | |
414 | ||
415 | /* Bitfields are never addressable. */ | |
416 | else if (TREE_CODE (t) == BIT_FIELD_REF) | |
417 | return 0; | |
418 | ||
8ac61af7 RK |
419 | /* Fields are addressable unless they are marked as nonaddressable or |
420 | the containing type has alias set 0. */ | |
6e24b709 RK |
421 | else if (TREE_CODE (t) == COMPONENT_REF |
422 | && ! DECL_NONADDRESSABLE_P (TREE_OPERAND (t, 1)) | |
8ac61af7 | 423 | && get_alias_set (TREE_TYPE (TREE_OPERAND (t, 0))) != 0 |
6e24b709 RK |
424 | && can_address_p (TREE_OPERAND (t, 0))) |
425 | return 1; | |
426 | ||
8ac61af7 | 427 | /* Likewise for arrays. */ |
b4e3fabb | 428 | else if ((TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF) |
6e24b709 | 429 | && ! TYPE_NONALIASED_COMPONENT (TREE_TYPE (TREE_OPERAND (t, 0))) |
8ac61af7 | 430 | && get_alias_set (TREE_TYPE (TREE_OPERAND (t, 0))) != 0 |
6e24b709 RK |
431 | && can_address_p (TREE_OPERAND (t, 0))) |
432 | return 1; | |
433 | ||
434 | return 0; | |
435 | } | |
436 | ||
3bdf5ad1 RK |
437 | /* Return the alias set for T, which may be either a type or an |
438 | expression. Call language-specific routine for help, if needed. */ | |
439 | ||
440 | HOST_WIDE_INT | |
441 | get_alias_set (t) | |
442 | tree t; | |
443 | { | |
444 | HOST_WIDE_INT set; | |
3bdf5ad1 RK |
445 | |
446 | /* If we're not doing any alias analysis, just assume everything | |
447 | aliases everything else. Also return 0 if this or its type is | |
448 | an error. */ | |
449 | if (! flag_strict_aliasing || t == error_mark_node | |
450 | || (! TYPE_P (t) | |
451 | && (TREE_TYPE (t) == 0 || TREE_TYPE (t) == error_mark_node))) | |
452 | return 0; | |
453 | ||
454 | /* We can be passed either an expression or a type. This and the | |
f47e9b4e RK |
455 | language-specific routine may make mutually-recursive calls to each other |
456 | to figure out what to do. At each juncture, we see if this is a tree | |
457 | that the language may need to handle specially. First handle things that | |
738cc472 | 458 | aren't types. */ |
f824e5c3 | 459 | if (! TYPE_P (t)) |
3bdf5ad1 | 460 | { |
738cc472 RK |
461 | tree inner = t; |
462 | tree placeholder_ptr = 0; | |
463 | ||
8ac61af7 RK |
464 | /* Remove any nops, then give the language a chance to do |
465 | something with this tree before we look at it. */ | |
466 | STRIP_NOPS (t); | |
467 | set = (*lang_hooks.get_alias_set) (t); | |
468 | if (set != -1) | |
469 | return set; | |
470 | ||
738cc472 | 471 | /* First see if the actual object referenced is an INDIRECT_REF from a |
8ac61af7 | 472 | restrict-qualified pointer or a "void *". Replace |
738cc472 | 473 | PLACEHOLDER_EXPRs. */ |
8ac61af7 | 474 | while (TREE_CODE (inner) == PLACEHOLDER_EXPR |
738cc472 RK |
475 | || handled_component_p (inner)) |
476 | { | |
477 | if (TREE_CODE (inner) == PLACEHOLDER_EXPR) | |
478 | inner = find_placeholder (inner, &placeholder_ptr); | |
479 | else | |
480 | inner = TREE_OPERAND (inner, 0); | |
8ac61af7 RK |
481 | |
482 | STRIP_NOPS (inner); | |
738cc472 RK |
483 | } |
484 | ||
485 | /* Check for accesses through restrict-qualified pointers. */ | |
486 | if (TREE_CODE (inner) == INDIRECT_REF) | |
487 | { | |
488 | tree decl = find_base_decl (TREE_OPERAND (inner, 0)); | |
489 | ||
490 | if (decl && DECL_POINTER_ALIAS_SET_KNOWN_P (decl)) | |
491 | { | |
e5837c07 | 492 | /* If we haven't computed the actual alias set, do it now. */ |
738cc472 RK |
493 | if (DECL_POINTER_ALIAS_SET (decl) == -2) |
494 | { | |
495 | /* No two restricted pointers can point at the same thing. | |
496 | However, a restricted pointer can point at the same thing | |
497 | as an unrestricted pointer, if that unrestricted pointer | |
498 | is based on the restricted pointer. So, we make the | |
499 | alias set for the restricted pointer a subset of the | |
500 | alias set for the type pointed to by the type of the | |
501 | decl. */ | |
502 | HOST_WIDE_INT pointed_to_alias_set | |
503 | = get_alias_set (TREE_TYPE (TREE_TYPE (decl))); | |
504 | ||
505 | if (pointed_to_alias_set == 0) | |
506 | /* It's not legal to make a subset of alias set zero. */ | |
507 | ; | |
508 | else | |
509 | { | |
510 | DECL_POINTER_ALIAS_SET (decl) = new_alias_set (); | |
511 | record_alias_subset (pointed_to_alias_set, | |
512 | DECL_POINTER_ALIAS_SET (decl)); | |
513 | } | |
514 | } | |
515 | ||
516 | /* We use the alias set indicated in the declaration. */ | |
517 | return DECL_POINTER_ALIAS_SET (decl); | |
518 | } | |
519 | ||
520 | /* If we have an INDIRECT_REF via a void pointer, we don't | |
521 | know anything about what that might alias. */ | |
522 | else if (TREE_CODE (TREE_TYPE (inner)) == VOID_TYPE) | |
523 | return 0; | |
524 | } | |
525 | ||
526 | /* Otherwise, pick up the outermost object that we could have a pointer | |
527 | to, processing conversion and PLACEHOLDER_EXPR as above. */ | |
528 | placeholder_ptr = 0; | |
8ac61af7 | 529 | while (TREE_CODE (t) == PLACEHOLDER_EXPR |
f47e9b4e RK |
530 | || (handled_component_p (t) && ! can_address_p (t))) |
531 | { | |
f47e9b4e | 532 | if (TREE_CODE (t) == PLACEHOLDER_EXPR) |
738cc472 | 533 | t = find_placeholder (t, &placeholder_ptr); |
f47e9b4e RK |
534 | else |
535 | t = TREE_OPERAND (t, 0); | |
f824e5c3 | 536 | |
8ac61af7 RK |
537 | STRIP_NOPS (t); |
538 | } | |
f824e5c3 | 539 | |
738cc472 RK |
540 | /* If we've already determined the alias set for a decl, just return |
541 | it. This is necessary for C++ anonymous unions, whose component | |
542 | variables don't look like union members (boo!). */ | |
5755cd38 JM |
543 | if (TREE_CODE (t) == VAR_DECL |
544 | && DECL_RTL_SET_P (t) && GET_CODE (DECL_RTL (t)) == MEM) | |
545 | return MEM_ALIAS_SET (DECL_RTL (t)); | |
546 | ||
f824e5c3 RK |
547 | /* Now all we care about is the type. */ |
548 | t = TREE_TYPE (t); | |
3bdf5ad1 RK |
549 | } |
550 | ||
3bdf5ad1 RK |
551 | /* Variant qualifiers don't affect the alias set, so get the main |
552 | variant. If this is a type with a known alias set, return it. */ | |
553 | t = TYPE_MAIN_VARIANT (t); | |
738cc472 | 554 | if (TYPE_ALIAS_SET_KNOWN_P (t)) |
3bdf5ad1 RK |
555 | return TYPE_ALIAS_SET (t); |
556 | ||
557 | /* See if the language has special handling for this type. */ | |
8ac61af7 RK |
558 | set = (*lang_hooks.get_alias_set) (t); |
559 | if (set != -1) | |
738cc472 | 560 | return set; |
2bf105ab | 561 | |
3bdf5ad1 RK |
562 | /* There are no objects of FUNCTION_TYPE, so there's no point in |
563 | using up an alias set for them. (There are, of course, pointers | |
564 | and references to functions, but that's different.) */ | |
565 | else if (TREE_CODE (t) == FUNCTION_TYPE) | |
566 | set = 0; | |
567 | else | |
568 | /* Otherwise make a new alias set for this type. */ | |
569 | set = new_alias_set (); | |
570 | ||
571 | TYPE_ALIAS_SET (t) = set; | |
2bf105ab RK |
572 | |
573 | /* If this is an aggregate type, we must record any component aliasing | |
574 | information. */ | |
1d79fd2c | 575 | if (AGGREGATE_TYPE_P (t) || TREE_CODE (t) == COMPLEX_TYPE) |
2bf105ab RK |
576 | record_component_aliases (t); |
577 | ||
3bdf5ad1 RK |
578 | return set; |
579 | } | |
580 | ||
581 | /* Return a brand-new alias set. */ | |
582 | ||
583 | HOST_WIDE_INT | |
584 | new_alias_set () | |
585 | { | |
586 | static HOST_WIDE_INT last_alias_set; | |
587 | ||
588 | if (flag_strict_aliasing) | |
589 | return ++last_alias_set; | |
590 | else | |
591 | return 0; | |
592 | } | |
3932261a MM |
593 | |
594 | /* Indicate that things in SUBSET can alias things in SUPERSET, but | |
595 | not vice versa. For example, in C, a store to an `int' can alias a | |
596 | structure containing an `int', but not vice versa. Here, the | |
597 | structure would be the SUPERSET and `int' the SUBSET. This | |
a0c33338 | 598 | function should be called only once per SUPERSET/SUBSET pair. |
3932261a MM |
599 | |
600 | It is illegal for SUPERSET to be zero; everything is implicitly a | |
601 | subset of alias set zero. */ | |
602 | ||
603 | void | |
604 | record_alias_subset (superset, subset) | |
3bdf5ad1 RK |
605 | HOST_WIDE_INT superset; |
606 | HOST_WIDE_INT subset; | |
3932261a MM |
607 | { |
608 | alias_set_entry superset_entry; | |
609 | alias_set_entry subset_entry; | |
610 | ||
f47e9b4e RK |
611 | /* It is possible in complex type situations for both sets to be the same, |
612 | in which case we can ignore this operation. */ | |
613 | if (superset == subset) | |
614 | return; | |
615 | ||
3932261a MM |
616 | if (superset == 0) |
617 | abort (); | |
618 | ||
619 | superset_entry = get_alias_set_entry (superset); | |
d4b60170 | 620 | if (superset_entry == 0) |
3932261a MM |
621 | { |
622 | /* Create an entry for the SUPERSET, so that we have a place to | |
623 | attach the SUBSET. */ | |
d4b60170 RK |
624 | superset_entry |
625 | = (alias_set_entry) xmalloc (sizeof (struct alias_set_entry)); | |
3932261a MM |
626 | superset_entry->alias_set = superset; |
627 | superset_entry->children | |
30f72379 | 628 | = splay_tree_new (splay_tree_compare_ints, 0, 0); |
570eb5c8 | 629 | superset_entry->has_zero_child = 0; |
d4b60170 | 630 | splay_tree_insert (alias_sets, (splay_tree_key) superset, |
3932261a | 631 | (splay_tree_value) superset_entry); |
3932261a MM |
632 | } |
633 | ||
2bf105ab RK |
634 | if (subset == 0) |
635 | superset_entry->has_zero_child = 1; | |
636 | else | |
637 | { | |
638 | subset_entry = get_alias_set_entry (subset); | |
639 | /* If there is an entry for the subset, enter all of its children | |
640 | (if they are not already present) as children of the SUPERSET. */ | |
641 | if (subset_entry) | |
642 | { | |
643 | if (subset_entry->has_zero_child) | |
644 | superset_entry->has_zero_child = 1; | |
d4b60170 | 645 | |
2bf105ab RK |
646 | splay_tree_foreach (subset_entry->children, insert_subset_children, |
647 | superset_entry->children); | |
648 | } | |
3932261a | 649 | |
2bf105ab RK |
650 | /* Enter the SUBSET itself as a child of the SUPERSET. */ |
651 | splay_tree_insert (superset_entry->children, | |
652 | (splay_tree_key) subset, 0); | |
653 | } | |
3932261a MM |
654 | } |
655 | ||
a0c33338 RK |
656 | /* Record that component types of TYPE, if any, are part of that type for |
657 | aliasing purposes. For record types, we only record component types | |
658 | for fields that are marked addressable. For array types, we always | |
659 | record the component types, so the front end should not call this | |
660 | function if the individual component aren't addressable. */ | |
661 | ||
662 | void | |
663 | record_component_aliases (type) | |
664 | tree type; | |
665 | { | |
3bdf5ad1 | 666 | HOST_WIDE_INT superset = get_alias_set (type); |
a0c33338 RK |
667 | tree field; |
668 | ||
669 | if (superset == 0) | |
670 | return; | |
671 | ||
672 | switch (TREE_CODE (type)) | |
673 | { | |
674 | case ARRAY_TYPE: | |
2bf105ab RK |
675 | if (! TYPE_NONALIASED_COMPONENT (type)) |
676 | record_alias_subset (superset, get_alias_set (TREE_TYPE (type))); | |
a0c33338 RK |
677 | break; |
678 | ||
679 | case RECORD_TYPE: | |
680 | case UNION_TYPE: | |
681 | case QUAL_UNION_TYPE: | |
682 | for (field = TYPE_FIELDS (type); field != 0; field = TREE_CHAIN (field)) | |
b16a49a1 | 683 | if (TREE_CODE (field) == FIELD_DECL && ! DECL_NONADDRESSABLE_P (field)) |
2bf105ab | 684 | record_alias_subset (superset, get_alias_set (TREE_TYPE (field))); |
a0c33338 RK |
685 | break; |
686 | ||
1d79fd2c JW |
687 | case COMPLEX_TYPE: |
688 | record_alias_subset (superset, get_alias_set (TREE_TYPE (type))); | |
689 | break; | |
690 | ||
a0c33338 RK |
691 | default: |
692 | break; | |
693 | } | |
694 | } | |
695 | ||
3bdf5ad1 RK |
696 | /* Allocate an alias set for use in storing and reading from the varargs |
697 | spill area. */ | |
698 | ||
699 | HOST_WIDE_INT | |
700 | get_varargs_alias_set () | |
701 | { | |
702 | static HOST_WIDE_INT set = -1; | |
703 | ||
704 | if (set == -1) | |
705 | set = new_alias_set (); | |
706 | ||
707 | return set; | |
708 | } | |
709 | ||
710 | /* Likewise, but used for the fixed portions of the frame, e.g., register | |
711 | save areas. */ | |
712 | ||
713 | HOST_WIDE_INT | |
714 | get_frame_alias_set () | |
715 | { | |
716 | static HOST_WIDE_INT set = -1; | |
717 | ||
718 | if (set == -1) | |
719 | set = new_alias_set (); | |
720 | ||
721 | return set; | |
722 | } | |
723 | ||
2a2c8203 JC |
724 | /* Inside SRC, the source of a SET, find a base address. */ |
725 | ||
9ae8ffe7 JL |
726 | static rtx |
727 | find_base_value (src) | |
b3694847 | 728 | rtx src; |
9ae8ffe7 | 729 | { |
713f41f9 | 730 | unsigned int regno; |
0aacc8ed | 731 | |
9ae8ffe7 JL |
732 | switch (GET_CODE (src)) |
733 | { | |
734 | case SYMBOL_REF: | |
735 | case LABEL_REF: | |
736 | return src; | |
737 | ||
738 | case REG: | |
fb6754f0 | 739 | regno = REGNO (src); |
d4b60170 | 740 | /* At the start of a function, argument registers have known base |
2a2c8203 JC |
741 | values which may be lost later. Returning an ADDRESS |
742 | expression here allows optimization based on argument values | |
743 | even when the argument registers are used for other purposes. */ | |
713f41f9 BS |
744 | if (regno < FIRST_PSEUDO_REGISTER && copying_arguments) |
745 | return new_reg_base_value[regno]; | |
73774bc7 | 746 | |
eaf407a5 | 747 | /* If a pseudo has a known base value, return it. Do not do this |
9b462c42 RH |
748 | for non-fixed hard regs since it can result in a circular |
749 | dependency chain for registers which have values at function entry. | |
eaf407a5 JL |
750 | |
751 | The test above is not sufficient because the scheduler may move | |
752 | a copy out of an arg reg past the NOTE_INSN_FUNCTION_BEGIN. */ | |
9b462c42 | 753 | if ((regno >= FIRST_PSEUDO_REGISTER || fixed_regs[regno]) |
713f41f9 BS |
754 | && regno < reg_base_value_size |
755 | && reg_base_value[regno]) | |
756 | return reg_base_value[regno]; | |
73774bc7 | 757 | |
9ae8ffe7 JL |
758 | return src; |
759 | ||
760 | case MEM: | |
761 | /* Check for an argument passed in memory. Only record in the | |
762 | copying-arguments block; it is too hard to track changes | |
763 | otherwise. */ | |
764 | if (copying_arguments | |
765 | && (XEXP (src, 0) == arg_pointer_rtx | |
766 | || (GET_CODE (XEXP (src, 0)) == PLUS | |
767 | && XEXP (XEXP (src, 0), 0) == arg_pointer_rtx))) | |
38a448ca | 768 | return gen_rtx_ADDRESS (VOIDmode, src); |
9ae8ffe7 JL |
769 | return 0; |
770 | ||
771 | case CONST: | |
772 | src = XEXP (src, 0); | |
773 | if (GET_CODE (src) != PLUS && GET_CODE (src) != MINUS) | |
774 | break; | |
d4b60170 | 775 | |
ec5c56db | 776 | /* ... fall through ... */ |
2a2c8203 | 777 | |
9ae8ffe7 JL |
778 | case PLUS: |
779 | case MINUS: | |
2a2c8203 | 780 | { |
ec907dd8 JL |
781 | rtx temp, src_0 = XEXP (src, 0), src_1 = XEXP (src, 1); |
782 | ||
0134bf2d DE |
783 | /* If either operand is a REG that is a known pointer, then it |
784 | is the base. */ | |
785 | if (REG_P (src_0) && REG_POINTER (src_0)) | |
786 | return find_base_value (src_0); | |
787 | if (REG_P (src_1) && REG_POINTER (src_1)) | |
788 | return find_base_value (src_1); | |
789 | ||
ec907dd8 JL |
790 | /* If either operand is a REG, then see if we already have |
791 | a known value for it. */ | |
0134bf2d | 792 | if (REG_P (src_0)) |
ec907dd8 JL |
793 | { |
794 | temp = find_base_value (src_0); | |
d4b60170 | 795 | if (temp != 0) |
ec907dd8 JL |
796 | src_0 = temp; |
797 | } | |
798 | ||
0134bf2d | 799 | if (REG_P (src_1)) |
ec907dd8 JL |
800 | { |
801 | temp = find_base_value (src_1); | |
d4b60170 | 802 | if (temp!= 0) |
ec907dd8 JL |
803 | src_1 = temp; |
804 | } | |
2a2c8203 | 805 | |
0134bf2d DE |
806 | /* If either base is named object or a special address |
807 | (like an argument or stack reference), then use it for the | |
808 | base term. */ | |
809 | if (src_0 != 0 | |
810 | && (GET_CODE (src_0) == SYMBOL_REF | |
811 | || GET_CODE (src_0) == LABEL_REF | |
812 | || (GET_CODE (src_0) == ADDRESS | |
813 | && GET_MODE (src_0) != VOIDmode))) | |
814 | return src_0; | |
815 | ||
816 | if (src_1 != 0 | |
817 | && (GET_CODE (src_1) == SYMBOL_REF | |
818 | || GET_CODE (src_1) == LABEL_REF | |
819 | || (GET_CODE (src_1) == ADDRESS | |
820 | && GET_MODE (src_1) != VOIDmode))) | |
821 | return src_1; | |
822 | ||
d4b60170 | 823 | /* Guess which operand is the base address: |
ec907dd8 JL |
824 | If either operand is a symbol, then it is the base. If |
825 | either operand is a CONST_INT, then the other is the base. */ | |
d4b60170 | 826 | if (GET_CODE (src_1) == CONST_INT || CONSTANT_P (src_0)) |
2a2c8203 | 827 | return find_base_value (src_0); |
d4b60170 | 828 | else if (GET_CODE (src_0) == CONST_INT || CONSTANT_P (src_1)) |
ec907dd8 JL |
829 | return find_base_value (src_1); |
830 | ||
9ae8ffe7 | 831 | return 0; |
2a2c8203 JC |
832 | } |
833 | ||
834 | case LO_SUM: | |
835 | /* The standard form is (lo_sum reg sym) so look only at the | |
836 | second operand. */ | |
837 | return find_base_value (XEXP (src, 1)); | |
9ae8ffe7 JL |
838 | |
839 | case AND: | |
840 | /* If the second operand is constant set the base | |
ec5c56db | 841 | address to the first operand. */ |
2a2c8203 JC |
842 | if (GET_CODE (XEXP (src, 1)) == CONST_INT && INTVAL (XEXP (src, 1)) != 0) |
843 | return find_base_value (XEXP (src, 0)); | |
9ae8ffe7 JL |
844 | return 0; |
845 | ||
61f0131c R |
846 | case TRUNCATE: |
847 | if (GET_MODE_SIZE (GET_MODE (src)) < GET_MODE_SIZE (Pmode)) | |
848 | break; | |
849 | /* Fall through. */ | |
9ae8ffe7 | 850 | case HIGH: |
d288e53d DE |
851 | case PRE_INC: |
852 | case PRE_DEC: | |
853 | case POST_INC: | |
854 | case POST_DEC: | |
855 | case PRE_MODIFY: | |
856 | case POST_MODIFY: | |
2a2c8203 | 857 | return find_base_value (XEXP (src, 0)); |
1d300e19 | 858 | |
0aacc8ed RK |
859 | case ZERO_EXTEND: |
860 | case SIGN_EXTEND: /* used for NT/Alpha pointers */ | |
861 | { | |
862 | rtx temp = find_base_value (XEXP (src, 0)); | |
863 | ||
864 | #ifdef POINTERS_EXTEND_UNSIGNED | |
865 | if (temp != 0 && CONSTANT_P (temp) && GET_MODE (temp) != Pmode) | |
866 | temp = convert_memory_address (Pmode, temp); | |
867 | #endif | |
868 | ||
869 | return temp; | |
870 | } | |
871 | ||
1d300e19 KG |
872 | default: |
873 | break; | |
9ae8ffe7 JL |
874 | } |
875 | ||
876 | return 0; | |
877 | } | |
878 | ||
879 | /* Called from init_alias_analysis indirectly through note_stores. */ | |
880 | ||
d4b60170 | 881 | /* While scanning insns to find base values, reg_seen[N] is nonzero if |
9ae8ffe7 JL |
882 | register N has been set in this function. */ |
883 | static char *reg_seen; | |
884 | ||
13309a5f JC |
885 | /* Addresses which are known not to alias anything else are identified |
886 | by a unique integer. */ | |
ec907dd8 JL |
887 | static int unique_id; |
888 | ||
2a2c8203 | 889 | static void |
84832317 | 890 | record_set (dest, set, data) |
9ae8ffe7 | 891 | rtx dest, set; |
84832317 | 892 | void *data ATTRIBUTE_UNUSED; |
9ae8ffe7 | 893 | { |
b3694847 | 894 | unsigned regno; |
9ae8ffe7 JL |
895 | rtx src; |
896 | ||
897 | if (GET_CODE (dest) != REG) | |
898 | return; | |
899 | ||
fb6754f0 | 900 | regno = REGNO (dest); |
9ae8ffe7 | 901 | |
ac606739 GS |
902 | if (regno >= reg_base_value_size) |
903 | abort (); | |
904 | ||
9ae8ffe7 JL |
905 | if (set) |
906 | { | |
907 | /* A CLOBBER wipes out any old value but does not prevent a previously | |
908 | unset register from acquiring a base address (i.e. reg_seen is not | |
909 | set). */ | |
910 | if (GET_CODE (set) == CLOBBER) | |
911 | { | |
ec907dd8 | 912 | new_reg_base_value[regno] = 0; |
9ae8ffe7 JL |
913 | return; |
914 | } | |
915 | src = SET_SRC (set); | |
916 | } | |
917 | else | |
918 | { | |
9ae8ffe7 JL |
919 | if (reg_seen[regno]) |
920 | { | |
ec907dd8 | 921 | new_reg_base_value[regno] = 0; |
9ae8ffe7 JL |
922 | return; |
923 | } | |
924 | reg_seen[regno] = 1; | |
38a448ca RH |
925 | new_reg_base_value[regno] = gen_rtx_ADDRESS (Pmode, |
926 | GEN_INT (unique_id++)); | |
9ae8ffe7 JL |
927 | return; |
928 | } | |
929 | ||
930 | /* This is not the first set. If the new value is not related to the | |
931 | old value, forget the base value. Note that the following code is | |
932 | not detected: | |
933 | extern int x, y; int *p = &x; p += (&y-&x); | |
934 | ANSI C does not allow computing the difference of addresses | |
935 | of distinct top level objects. */ | |
ec907dd8 | 936 | if (new_reg_base_value[regno]) |
9ae8ffe7 JL |
937 | switch (GET_CODE (src)) |
938 | { | |
2a2c8203 | 939 | case LO_SUM: |
9ae8ffe7 JL |
940 | case MINUS: |
941 | if (XEXP (src, 0) != dest && XEXP (src, 1) != dest) | |
ec907dd8 | 942 | new_reg_base_value[regno] = 0; |
9ae8ffe7 | 943 | break; |
61f0131c R |
944 | case PLUS: |
945 | /* If the value we add in the PLUS is also a valid base value, | |
946 | this might be the actual base value, and the original value | |
947 | an index. */ | |
948 | { | |
949 | rtx other = NULL_RTX; | |
950 | ||
951 | if (XEXP (src, 0) == dest) | |
952 | other = XEXP (src, 1); | |
953 | else if (XEXP (src, 1) == dest) | |
954 | other = XEXP (src, 0); | |
955 | ||
956 | if (! other || find_base_value (other)) | |
957 | new_reg_base_value[regno] = 0; | |
958 | break; | |
959 | } | |
9ae8ffe7 JL |
960 | case AND: |
961 | if (XEXP (src, 0) != dest || GET_CODE (XEXP (src, 1)) != CONST_INT) | |
ec907dd8 | 962 | new_reg_base_value[regno] = 0; |
9ae8ffe7 | 963 | break; |
9ae8ffe7 | 964 | default: |
ec907dd8 | 965 | new_reg_base_value[regno] = 0; |
9ae8ffe7 JL |
966 | break; |
967 | } | |
968 | /* If this is the first set of a register, record the value. */ | |
969 | else if ((regno >= FIRST_PSEUDO_REGISTER || ! fixed_regs[regno]) | |
ec907dd8 JL |
970 | && ! reg_seen[regno] && new_reg_base_value[regno] == 0) |
971 | new_reg_base_value[regno] = find_base_value (src); | |
9ae8ffe7 JL |
972 | |
973 | reg_seen[regno] = 1; | |
974 | } | |
975 | ||
ac3d9668 RK |
976 | /* Called from loop optimization when a new pseudo-register is |
977 | created. It indicates that REGNO is being set to VAL. f INVARIANT | |
978 | is true then this value also describes an invariant relationship | |
979 | which can be used to deduce that two registers with unknown values | |
980 | are different. */ | |
d4b60170 | 981 | |
9ae8ffe7 | 982 | void |
de12be17 | 983 | record_base_value (regno, val, invariant) |
ac3d9668 | 984 | unsigned int regno; |
9ae8ffe7 | 985 | rtx val; |
de12be17 | 986 | int invariant; |
9ae8ffe7 | 987 | { |
ac3d9668 | 988 | if (regno >= reg_base_value_size) |
9ae8ffe7 | 989 | return; |
de12be17 | 990 | |
de12be17 JC |
991 | if (invariant && alias_invariant) |
992 | alias_invariant[regno] = val; | |
993 | ||
9ae8ffe7 JL |
994 | if (GET_CODE (val) == REG) |
995 | { | |
fb6754f0 BS |
996 | if (REGNO (val) < reg_base_value_size) |
997 | reg_base_value[regno] = reg_base_value[REGNO (val)]; | |
d4b60170 | 998 | |
9ae8ffe7 JL |
999 | return; |
1000 | } | |
d4b60170 | 1001 | |
9ae8ffe7 JL |
1002 | reg_base_value[regno] = find_base_value (val); |
1003 | } | |
1004 | ||
43fe47ca JW |
1005 | /* Clear alias info for a register. This is used if an RTL transformation |
1006 | changes the value of a register. This is used in flow by AUTO_INC_DEC | |
1007 | optimizations. We don't need to clear reg_base_value, since flow only | |
1008 | changes the offset. */ | |
1009 | ||
1010 | void | |
5197bd50 RK |
1011 | clear_reg_alias_info (reg) |
1012 | rtx reg; | |
43fe47ca | 1013 | { |
4e1a4144 JW |
1014 | unsigned int regno = REGNO (reg); |
1015 | ||
1016 | if (regno < reg_known_value_size && regno >= FIRST_PSEUDO_REGISTER) | |
1017 | reg_known_value[regno] = reg; | |
43fe47ca JW |
1018 | } |
1019 | ||
db048faf MM |
1020 | /* Returns a canonical version of X, from the point of view alias |
1021 | analysis. (For example, if X is a MEM whose address is a register, | |
1022 | and the register has a known value (say a SYMBOL_REF), then a MEM | |
1023 | whose address is the SYMBOL_REF is returned.) */ | |
1024 | ||
1025 | rtx | |
9ae8ffe7 JL |
1026 | canon_rtx (x) |
1027 | rtx x; | |
1028 | { | |
1029 | /* Recursively look for equivalences. */ | |
fb6754f0 BS |
1030 | if (GET_CODE (x) == REG && REGNO (x) >= FIRST_PSEUDO_REGISTER |
1031 | && REGNO (x) < reg_known_value_size) | |
1032 | return reg_known_value[REGNO (x)] == x | |
1033 | ? x : canon_rtx (reg_known_value[REGNO (x)]); | |
9ae8ffe7 JL |
1034 | else if (GET_CODE (x) == PLUS) |
1035 | { | |
1036 | rtx x0 = canon_rtx (XEXP (x, 0)); | |
1037 | rtx x1 = canon_rtx (XEXP (x, 1)); | |
1038 | ||
1039 | if (x0 != XEXP (x, 0) || x1 != XEXP (x, 1)) | |
1040 | { | |
9ae8ffe7 | 1041 | if (GET_CODE (x0) == CONST_INT) |
ed8908e7 | 1042 | return plus_constant (x1, INTVAL (x0)); |
9ae8ffe7 | 1043 | else if (GET_CODE (x1) == CONST_INT) |
ed8908e7 | 1044 | return plus_constant (x0, INTVAL (x1)); |
38a448ca | 1045 | return gen_rtx_PLUS (GET_MODE (x), x0, x1); |
9ae8ffe7 JL |
1046 | } |
1047 | } | |
d4b60170 | 1048 | |
9ae8ffe7 JL |
1049 | /* This gives us much better alias analysis when called from |
1050 | the loop optimizer. Note we want to leave the original | |
1051 | MEM alone, but need to return the canonicalized MEM with | |
1052 | all the flags with their original values. */ | |
1053 | else if (GET_CODE (x) == MEM) | |
f1ec5147 | 1054 | x = replace_equiv_address_nv (x, canon_rtx (XEXP (x, 0))); |
d4b60170 | 1055 | |
9ae8ffe7 JL |
1056 | return x; |
1057 | } | |
1058 | ||
1059 | /* Return 1 if X and Y are identical-looking rtx's. | |
1060 | ||
1061 | We use the data in reg_known_value above to see if two registers with | |
1062 | different numbers are, in fact, equivalent. */ | |
1063 | ||
1064 | static int | |
1065 | rtx_equal_for_memref_p (x, y) | |
1066 | rtx x, y; | |
1067 | { | |
b3694847 SS |
1068 | int i; |
1069 | int j; | |
1070 | enum rtx_code code; | |
1071 | const char *fmt; | |
9ae8ffe7 JL |
1072 | |
1073 | if (x == 0 && y == 0) | |
1074 | return 1; | |
1075 | if (x == 0 || y == 0) | |
1076 | return 0; | |
d4b60170 | 1077 | |
9ae8ffe7 JL |
1078 | x = canon_rtx (x); |
1079 | y = canon_rtx (y); | |
1080 | ||
1081 | if (x == y) | |
1082 | return 1; | |
1083 | ||
1084 | code = GET_CODE (x); | |
1085 | /* Rtx's of different codes cannot be equal. */ | |
1086 | if (code != GET_CODE (y)) | |
1087 | return 0; | |
1088 | ||
1089 | /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. | |
1090 | (REG:SI x) and (REG:HI x) are NOT equivalent. */ | |
1091 | ||
1092 | if (GET_MODE (x) != GET_MODE (y)) | |
1093 | return 0; | |
1094 | ||
db048faf MM |
1095 | /* Some RTL can be compared without a recursive examination. */ |
1096 | switch (code) | |
1097 | { | |
ab59db3c BS |
1098 | case VALUE: |
1099 | return CSELIB_VAL_PTR (x) == CSELIB_VAL_PTR (y); | |
1100 | ||
db048faf MM |
1101 | case REG: |
1102 | return REGNO (x) == REGNO (y); | |
1103 | ||
1104 | case LABEL_REF: | |
1105 | return XEXP (x, 0) == XEXP (y, 0); | |
1106 | ||
1107 | case SYMBOL_REF: | |
1108 | return XSTR (x, 0) == XSTR (y, 0); | |
1109 | ||
1110 | case CONST_INT: | |
1111 | case CONST_DOUBLE: | |
1112 | /* There's no need to compare the contents of CONST_DOUBLEs or | |
1113 | CONST_INTs because pointer equality is a good enough | |
1114 | comparison for these nodes. */ | |
1115 | return 0; | |
1116 | ||
1117 | case ADDRESSOF: | |
831ecbd4 RK |
1118 | return (XINT (x, 1) == XINT (y, 1) |
1119 | && rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 0))); | |
db048faf MM |
1120 | |
1121 | default: | |
1122 | break; | |
1123 | } | |
9ae8ffe7 JL |
1124 | |
1125 | /* For commutative operations, the RTX match if the operand match in any | |
1126 | order. Also handle the simple binary and unary cases without a loop. */ | |
1127 | if (code == EQ || code == NE || GET_RTX_CLASS (code) == 'c') | |
1128 | return ((rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 0)) | |
1129 | && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 1))) | |
1130 | || (rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 1)) | |
1131 | && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 0)))); | |
1132 | else if (GET_RTX_CLASS (code) == '<' || GET_RTX_CLASS (code) == '2') | |
1133 | return (rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 0)) | |
1134 | && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 1))); | |
1135 | else if (GET_RTX_CLASS (code) == '1') | |
1136 | return rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 0)); | |
1137 | ||
1138 | /* Compare the elements. If any pair of corresponding elements | |
de12be17 JC |
1139 | fail to match, return 0 for the whole things. |
1140 | ||
1141 | Limit cases to types which actually appear in addresses. */ | |
9ae8ffe7 JL |
1142 | |
1143 | fmt = GET_RTX_FORMAT (code); | |
1144 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
1145 | { | |
1146 | switch (fmt[i]) | |
1147 | { | |
9ae8ffe7 JL |
1148 | case 'i': |
1149 | if (XINT (x, i) != XINT (y, i)) | |
1150 | return 0; | |
1151 | break; | |
1152 | ||
9ae8ffe7 JL |
1153 | case 'E': |
1154 | /* Two vectors must have the same length. */ | |
1155 | if (XVECLEN (x, i) != XVECLEN (y, i)) | |
1156 | return 0; | |
1157 | ||
1158 | /* And the corresponding elements must match. */ | |
1159 | for (j = 0; j < XVECLEN (x, i); j++) | |
d4b60170 RK |
1160 | if (rtx_equal_for_memref_p (XVECEXP (x, i, j), |
1161 | XVECEXP (y, i, j)) == 0) | |
9ae8ffe7 JL |
1162 | return 0; |
1163 | break; | |
1164 | ||
1165 | case 'e': | |
1166 | if (rtx_equal_for_memref_p (XEXP (x, i), XEXP (y, i)) == 0) | |
1167 | return 0; | |
1168 | break; | |
1169 | ||
3237ac18 AH |
1170 | /* This can happen for asm operands. */ |
1171 | case 's': | |
1172 | if (strcmp (XSTR (x, i), XSTR (y, i))) | |
1173 | return 0; | |
1174 | break; | |
1175 | ||
aee21ba9 JL |
1176 | /* This can happen for an asm which clobbers memory. */ |
1177 | case '0': | |
1178 | break; | |
1179 | ||
9ae8ffe7 JL |
1180 | /* It is believed that rtx's at this level will never |
1181 | contain anything but integers and other rtx's, | |
1182 | except for within LABEL_REFs and SYMBOL_REFs. */ | |
1183 | default: | |
1184 | abort (); | |
1185 | } | |
1186 | } | |
1187 | return 1; | |
1188 | } | |
1189 | ||
1190 | /* Given an rtx X, find a SYMBOL_REF or LABEL_REF within | |
1191 | X and return it, or return 0 if none found. */ | |
1192 | ||
1193 | static rtx | |
1194 | find_symbolic_term (x) | |
1195 | rtx x; | |
1196 | { | |
b3694847 SS |
1197 | int i; |
1198 | enum rtx_code code; | |
1199 | const char *fmt; | |
9ae8ffe7 JL |
1200 | |
1201 | code = GET_CODE (x); | |
1202 | if (code == SYMBOL_REF || code == LABEL_REF) | |
1203 | return x; | |
1204 | if (GET_RTX_CLASS (code) == 'o') | |
1205 | return 0; | |
1206 | ||
1207 | fmt = GET_RTX_FORMAT (code); | |
1208 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
1209 | { | |
1210 | rtx t; | |
1211 | ||
1212 | if (fmt[i] == 'e') | |
1213 | { | |
1214 | t = find_symbolic_term (XEXP (x, i)); | |
1215 | if (t != 0) | |
1216 | return t; | |
1217 | } | |
1218 | else if (fmt[i] == 'E') | |
1219 | break; | |
1220 | } | |
1221 | return 0; | |
1222 | } | |
1223 | ||
1224 | static rtx | |
1225 | find_base_term (x) | |
b3694847 | 1226 | rtx x; |
9ae8ffe7 | 1227 | { |
eab5c70a BS |
1228 | cselib_val *val; |
1229 | struct elt_loc_list *l; | |
1230 | ||
b949ea8b JW |
1231 | #if defined (FIND_BASE_TERM) |
1232 | /* Try machine-dependent ways to find the base term. */ | |
1233 | x = FIND_BASE_TERM (x); | |
1234 | #endif | |
1235 | ||
9ae8ffe7 JL |
1236 | switch (GET_CODE (x)) |
1237 | { | |
1238 | case REG: | |
1239 | return REG_BASE_VALUE (x); | |
1240 | ||
d288e53d DE |
1241 | case TRUNCATE: |
1242 | if (GET_MODE_SIZE (GET_MODE (x)) < GET_MODE_SIZE (Pmode)) | |
1243 | return 0; | |
1244 | /* Fall through. */ | |
9ae8ffe7 | 1245 | case HIGH: |
6d849a2a JL |
1246 | case PRE_INC: |
1247 | case PRE_DEC: | |
1248 | case POST_INC: | |
1249 | case POST_DEC: | |
d288e53d DE |
1250 | case PRE_MODIFY: |
1251 | case POST_MODIFY: | |
6d849a2a JL |
1252 | return find_base_term (XEXP (x, 0)); |
1253 | ||
1abade85 RK |
1254 | case ZERO_EXTEND: |
1255 | case SIGN_EXTEND: /* Used for Alpha/NT pointers */ | |
1256 | { | |
1257 | rtx temp = find_base_term (XEXP (x, 0)); | |
1258 | ||
1259 | #ifdef POINTERS_EXTEND_UNSIGNED | |
1260 | if (temp != 0 && CONSTANT_P (temp) && GET_MODE (temp) != Pmode) | |
1261 | temp = convert_memory_address (Pmode, temp); | |
1262 | #endif | |
1263 | ||
1264 | return temp; | |
1265 | } | |
1266 | ||
eab5c70a BS |
1267 | case VALUE: |
1268 | val = CSELIB_VAL_PTR (x); | |
1269 | for (l = val->locs; l; l = l->next) | |
1270 | if ((x = find_base_term (l->loc)) != 0) | |
1271 | return x; | |
1272 | return 0; | |
1273 | ||
9ae8ffe7 JL |
1274 | case CONST: |
1275 | x = XEXP (x, 0); | |
1276 | if (GET_CODE (x) != PLUS && GET_CODE (x) != MINUS) | |
1277 | return 0; | |
1278 | /* fall through */ | |
1279 | case LO_SUM: | |
1280 | case PLUS: | |
1281 | case MINUS: | |
1282 | { | |
3c567fae JL |
1283 | rtx tmp1 = XEXP (x, 0); |
1284 | rtx tmp2 = XEXP (x, 1); | |
1285 | ||
f5143c46 | 1286 | /* This is a little bit tricky since we have to determine which of |
3c567fae JL |
1287 | the two operands represents the real base address. Otherwise this |
1288 | routine may return the index register instead of the base register. | |
1289 | ||
1290 | That may cause us to believe no aliasing was possible, when in | |
1291 | fact aliasing is possible. | |
1292 | ||
1293 | We use a few simple tests to guess the base register. Additional | |
1294 | tests can certainly be added. For example, if one of the operands | |
1295 | is a shift or multiply, then it must be the index register and the | |
1296 | other operand is the base register. */ | |
1297 | ||
b949ea8b JW |
1298 | if (tmp1 == pic_offset_table_rtx && CONSTANT_P (tmp2)) |
1299 | return find_base_term (tmp2); | |
1300 | ||
3c567fae JL |
1301 | /* If either operand is known to be a pointer, then use it |
1302 | to determine the base term. */ | |
3502dc9c | 1303 | if (REG_P (tmp1) && REG_POINTER (tmp1)) |
3c567fae JL |
1304 | return find_base_term (tmp1); |
1305 | ||
3502dc9c | 1306 | if (REG_P (tmp2) && REG_POINTER (tmp2)) |
3c567fae JL |
1307 | return find_base_term (tmp2); |
1308 | ||
1309 | /* Neither operand was known to be a pointer. Go ahead and find the | |
1310 | base term for both operands. */ | |
1311 | tmp1 = find_base_term (tmp1); | |
1312 | tmp2 = find_base_term (tmp2); | |
1313 | ||
1314 | /* If either base term is named object or a special address | |
1315 | (like an argument or stack reference), then use it for the | |
1316 | base term. */ | |
d4b60170 | 1317 | if (tmp1 != 0 |
3c567fae JL |
1318 | && (GET_CODE (tmp1) == SYMBOL_REF |
1319 | || GET_CODE (tmp1) == LABEL_REF | |
1320 | || (GET_CODE (tmp1) == ADDRESS | |
1321 | && GET_MODE (tmp1) != VOIDmode))) | |
1322 | return tmp1; | |
1323 | ||
d4b60170 | 1324 | if (tmp2 != 0 |
3c567fae JL |
1325 | && (GET_CODE (tmp2) == SYMBOL_REF |
1326 | || GET_CODE (tmp2) == LABEL_REF | |
1327 | || (GET_CODE (tmp2) == ADDRESS | |
1328 | && GET_MODE (tmp2) != VOIDmode))) | |
1329 | return tmp2; | |
1330 | ||
1331 | /* We could not determine which of the two operands was the | |
1332 | base register and which was the index. So we can determine | |
1333 | nothing from the base alias check. */ | |
1334 | return 0; | |
9ae8ffe7 JL |
1335 | } |
1336 | ||
1337 | case AND: | |
d288e53d DE |
1338 | if (GET_CODE (XEXP (x, 1)) == CONST_INT && INTVAL (XEXP (x, 1)) != 0) |
1339 | return find_base_term (XEXP (x, 0)); | |
9ae8ffe7 JL |
1340 | return 0; |
1341 | ||
1342 | case SYMBOL_REF: | |
1343 | case LABEL_REF: | |
1344 | return x; | |
1345 | ||
d982e46e | 1346 | case ADDRESSOF: |
bb07060a | 1347 | return REG_BASE_VALUE (frame_pointer_rtx); |
d982e46e | 1348 | |
9ae8ffe7 JL |
1349 | default: |
1350 | return 0; | |
1351 | } | |
1352 | } | |
1353 | ||
1354 | /* Return 0 if the addresses X and Y are known to point to different | |
1355 | objects, 1 if they might be pointers to the same object. */ | |
1356 | ||
1357 | static int | |
56ee9281 | 1358 | base_alias_check (x, y, x_mode, y_mode) |
9ae8ffe7 | 1359 | rtx x, y; |
56ee9281 | 1360 | enum machine_mode x_mode, y_mode; |
9ae8ffe7 JL |
1361 | { |
1362 | rtx x_base = find_base_term (x); | |
1363 | rtx y_base = find_base_term (y); | |
1364 | ||
1c72c7f6 JC |
1365 | /* If the address itself has no known base see if a known equivalent |
1366 | value has one. If either address still has no known base, nothing | |
1367 | is known about aliasing. */ | |
1368 | if (x_base == 0) | |
1369 | { | |
1370 | rtx x_c; | |
d4b60170 | 1371 | |
1c72c7f6 JC |
1372 | if (! flag_expensive_optimizations || (x_c = canon_rtx (x)) == x) |
1373 | return 1; | |
d4b60170 | 1374 | |
1c72c7f6 JC |
1375 | x_base = find_base_term (x_c); |
1376 | if (x_base == 0) | |
1377 | return 1; | |
1378 | } | |
9ae8ffe7 | 1379 | |
1c72c7f6 JC |
1380 | if (y_base == 0) |
1381 | { | |
1382 | rtx y_c; | |
1383 | if (! flag_expensive_optimizations || (y_c = canon_rtx (y)) == y) | |
1384 | return 1; | |
d4b60170 | 1385 | |
1c72c7f6 JC |
1386 | y_base = find_base_term (y_c); |
1387 | if (y_base == 0) | |
1388 | return 1; | |
1389 | } | |
1390 | ||
1391 | /* If the base addresses are equal nothing is known about aliasing. */ | |
1392 | if (rtx_equal_p (x_base, y_base)) | |
9ae8ffe7 JL |
1393 | return 1; |
1394 | ||
56ee9281 RH |
1395 | /* The base addresses of the read and write are different expressions. |
1396 | If they are both symbols and they are not accessed via AND, there is | |
1397 | no conflict. We can bring knowledge of object alignment into play | |
1398 | here. For example, on alpha, "char a, b;" can alias one another, | |
1399 | though "char a; long b;" cannot. */ | |
9ae8ffe7 | 1400 | if (GET_CODE (x_base) != ADDRESS && GET_CODE (y_base) != ADDRESS) |
c02f035f | 1401 | { |
56ee9281 RH |
1402 | if (GET_CODE (x) == AND && GET_CODE (y) == AND) |
1403 | return 1; | |
1404 | if (GET_CODE (x) == AND | |
1405 | && (GET_CODE (XEXP (x, 1)) != CONST_INT | |
8fa2140d | 1406 | || (int) GET_MODE_UNIT_SIZE (y_mode) < -INTVAL (XEXP (x, 1)))) |
56ee9281 RH |
1407 | return 1; |
1408 | if (GET_CODE (y) == AND | |
1409 | && (GET_CODE (XEXP (y, 1)) != CONST_INT | |
8fa2140d | 1410 | || (int) GET_MODE_UNIT_SIZE (x_mode) < -INTVAL (XEXP (y, 1)))) |
56ee9281 | 1411 | return 1; |
b2972551 JL |
1412 | /* Differing symbols never alias. */ |
1413 | return 0; | |
c02f035f | 1414 | } |
9ae8ffe7 JL |
1415 | |
1416 | /* If one address is a stack reference there can be no alias: | |
1417 | stack references using different base registers do not alias, | |
1418 | a stack reference can not alias a parameter, and a stack reference | |
1419 | can not alias a global. */ | |
1420 | if ((GET_CODE (x_base) == ADDRESS && GET_MODE (x_base) == Pmode) | |
1421 | || (GET_CODE (y_base) == ADDRESS && GET_MODE (y_base) == Pmode)) | |
1422 | return 0; | |
1423 | ||
1424 | if (! flag_argument_noalias) | |
1425 | return 1; | |
1426 | ||
1427 | if (flag_argument_noalias > 1) | |
1428 | return 0; | |
1429 | ||
ec5c56db | 1430 | /* Weak noalias assertion (arguments are distinct, but may match globals). */ |
9ae8ffe7 JL |
1431 | return ! (GET_MODE (x_base) == VOIDmode && GET_MODE (y_base) == VOIDmode); |
1432 | } | |
1433 | ||
eab5c70a BS |
1434 | /* Convert the address X into something we can use. This is done by returning |
1435 | it unchanged unless it is a value; in the latter case we call cselib to get | |
1436 | a more useful rtx. */ | |
3bdf5ad1 | 1437 | |
a13d4ebf | 1438 | rtx |
eab5c70a BS |
1439 | get_addr (x) |
1440 | rtx x; | |
1441 | { | |
1442 | cselib_val *v; | |
1443 | struct elt_loc_list *l; | |
1444 | ||
1445 | if (GET_CODE (x) != VALUE) | |
1446 | return x; | |
1447 | v = CSELIB_VAL_PTR (x); | |
1448 | for (l = v->locs; l; l = l->next) | |
1449 | if (CONSTANT_P (l->loc)) | |
1450 | return l->loc; | |
1451 | for (l = v->locs; l; l = l->next) | |
1452 | if (GET_CODE (l->loc) != REG && GET_CODE (l->loc) != MEM) | |
1453 | return l->loc; | |
1454 | if (v->locs) | |
1455 | return v->locs->loc; | |
1456 | return x; | |
1457 | } | |
1458 | ||
39cec1ac MH |
1459 | /* Return the address of the (N_REFS + 1)th memory reference to ADDR |
1460 | where SIZE is the size in bytes of the memory reference. If ADDR | |
1461 | is not modified by the memory reference then ADDR is returned. */ | |
1462 | ||
1463 | rtx | |
1464 | addr_side_effect_eval (addr, size, n_refs) | |
1465 | rtx addr; | |
1466 | int size; | |
1467 | int n_refs; | |
1468 | { | |
1469 | int offset = 0; | |
1470 | ||
1471 | switch (GET_CODE (addr)) | |
1472 | { | |
1473 | case PRE_INC: | |
1474 | offset = (n_refs + 1) * size; | |
1475 | break; | |
1476 | case PRE_DEC: | |
1477 | offset = -(n_refs + 1) * size; | |
1478 | break; | |
1479 | case POST_INC: | |
1480 | offset = n_refs * size; | |
1481 | break; | |
1482 | case POST_DEC: | |
1483 | offset = -n_refs * size; | |
1484 | break; | |
1485 | ||
1486 | default: | |
1487 | return addr; | |
1488 | } | |
1489 | ||
1490 | if (offset) | |
1491 | addr = gen_rtx_PLUS (GET_MODE (addr), XEXP (addr, 0), GEN_INT (offset)); | |
1492 | else | |
1493 | addr = XEXP (addr, 0); | |
1494 | ||
1495 | return addr; | |
1496 | } | |
1497 | ||
9ae8ffe7 JL |
1498 | /* Return nonzero if X and Y (memory addresses) could reference the |
1499 | same location in memory. C is an offset accumulator. When | |
1500 | C is nonzero, we are testing aliases between X and Y + C. | |
1501 | XSIZE is the size in bytes of the X reference, | |
1502 | similarly YSIZE is the size in bytes for Y. | |
1503 | ||
1504 | If XSIZE or YSIZE is zero, we do not know the amount of memory being | |
1505 | referenced (the reference was BLKmode), so make the most pessimistic | |
1506 | assumptions. | |
1507 | ||
c02f035f RH |
1508 | If XSIZE or YSIZE is negative, we may access memory outside the object |
1509 | being referenced as a side effect. This can happen when using AND to | |
1510 | align memory references, as is done on the Alpha. | |
1511 | ||
9ae8ffe7 | 1512 | Nice to notice that varying addresses cannot conflict with fp if no |
0211b6ab | 1513 | local variables had their addresses taken, but that's too hard now. */ |
9ae8ffe7 | 1514 | |
9ae8ffe7 JL |
1515 | static int |
1516 | memrefs_conflict_p (xsize, x, ysize, y, c) | |
b3694847 | 1517 | rtx x, y; |
9ae8ffe7 JL |
1518 | int xsize, ysize; |
1519 | HOST_WIDE_INT c; | |
1520 | { | |
eab5c70a BS |
1521 | if (GET_CODE (x) == VALUE) |
1522 | x = get_addr (x); | |
1523 | if (GET_CODE (y) == VALUE) | |
1524 | y = get_addr (y); | |
9ae8ffe7 JL |
1525 | if (GET_CODE (x) == HIGH) |
1526 | x = XEXP (x, 0); | |
1527 | else if (GET_CODE (x) == LO_SUM) | |
1528 | x = XEXP (x, 1); | |
1529 | else | |
39cec1ac | 1530 | x = canon_rtx (addr_side_effect_eval (x, xsize, 0)); |
9ae8ffe7 JL |
1531 | if (GET_CODE (y) == HIGH) |
1532 | y = XEXP (y, 0); | |
1533 | else if (GET_CODE (y) == LO_SUM) | |
1534 | y = XEXP (y, 1); | |
1535 | else | |
39cec1ac | 1536 | y = canon_rtx (addr_side_effect_eval (y, ysize, 0)); |
9ae8ffe7 JL |
1537 | |
1538 | if (rtx_equal_for_memref_p (x, y)) | |
1539 | { | |
c02f035f | 1540 | if (xsize <= 0 || ysize <= 0) |
9ae8ffe7 JL |
1541 | return 1; |
1542 | if (c >= 0 && xsize > c) | |
1543 | return 1; | |
1544 | if (c < 0 && ysize+c > 0) | |
1545 | return 1; | |
1546 | return 0; | |
1547 | } | |
1548 | ||
6e73e666 JC |
1549 | /* This code used to check for conflicts involving stack references and |
1550 | globals but the base address alias code now handles these cases. */ | |
9ae8ffe7 JL |
1551 | |
1552 | if (GET_CODE (x) == PLUS) | |
1553 | { | |
1554 | /* The fact that X is canonicalized means that this | |
1555 | PLUS rtx is canonicalized. */ | |
1556 | rtx x0 = XEXP (x, 0); | |
1557 | rtx x1 = XEXP (x, 1); | |
1558 | ||
1559 | if (GET_CODE (y) == PLUS) | |
1560 | { | |
1561 | /* The fact that Y is canonicalized means that this | |
1562 | PLUS rtx is canonicalized. */ | |
1563 | rtx y0 = XEXP (y, 0); | |
1564 | rtx y1 = XEXP (y, 1); | |
1565 | ||
1566 | if (rtx_equal_for_memref_p (x1, y1)) | |
1567 | return memrefs_conflict_p (xsize, x0, ysize, y0, c); | |
1568 | if (rtx_equal_for_memref_p (x0, y0)) | |
1569 | return memrefs_conflict_p (xsize, x1, ysize, y1, c); | |
1570 | if (GET_CODE (x1) == CONST_INT) | |
63be02db JM |
1571 | { |
1572 | if (GET_CODE (y1) == CONST_INT) | |
1573 | return memrefs_conflict_p (xsize, x0, ysize, y0, | |
1574 | c - INTVAL (x1) + INTVAL (y1)); | |
1575 | else | |
1576 | return memrefs_conflict_p (xsize, x0, ysize, y, | |
1577 | c - INTVAL (x1)); | |
1578 | } | |
9ae8ffe7 JL |
1579 | else if (GET_CODE (y1) == CONST_INT) |
1580 | return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1)); | |
1581 | ||
6e73e666 | 1582 | return 1; |
9ae8ffe7 JL |
1583 | } |
1584 | else if (GET_CODE (x1) == CONST_INT) | |
1585 | return memrefs_conflict_p (xsize, x0, ysize, y, c - INTVAL (x1)); | |
1586 | } | |
1587 | else if (GET_CODE (y) == PLUS) | |
1588 | { | |
1589 | /* The fact that Y is canonicalized means that this | |
1590 | PLUS rtx is canonicalized. */ | |
1591 | rtx y0 = XEXP (y, 0); | |
1592 | rtx y1 = XEXP (y, 1); | |
1593 | ||
1594 | if (GET_CODE (y1) == CONST_INT) | |
1595 | return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1)); | |
1596 | else | |
1597 | return 1; | |
1598 | } | |
1599 | ||
1600 | if (GET_CODE (x) == GET_CODE (y)) | |
1601 | switch (GET_CODE (x)) | |
1602 | { | |
1603 | case MULT: | |
1604 | { | |
1605 | /* Handle cases where we expect the second operands to be the | |
1606 | same, and check only whether the first operand would conflict | |
1607 | or not. */ | |
1608 | rtx x0, y0; | |
1609 | rtx x1 = canon_rtx (XEXP (x, 1)); | |
1610 | rtx y1 = canon_rtx (XEXP (y, 1)); | |
1611 | if (! rtx_equal_for_memref_p (x1, y1)) | |
1612 | return 1; | |
1613 | x0 = canon_rtx (XEXP (x, 0)); | |
1614 | y0 = canon_rtx (XEXP (y, 0)); | |
1615 | if (rtx_equal_for_memref_p (x0, y0)) | |
1616 | return (xsize == 0 || ysize == 0 | |
1617 | || (c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)); | |
1618 | ||
1619 | /* Can't properly adjust our sizes. */ | |
1620 | if (GET_CODE (x1) != CONST_INT) | |
1621 | return 1; | |
1622 | xsize /= INTVAL (x1); | |
1623 | ysize /= INTVAL (x1); | |
1624 | c /= INTVAL (x1); | |
1625 | return memrefs_conflict_p (xsize, x0, ysize, y0, c); | |
1626 | } | |
1d300e19 | 1627 | |
de12be17 JC |
1628 | case REG: |
1629 | /* Are these registers known not to be equal? */ | |
1630 | if (alias_invariant) | |
1631 | { | |
e51712db | 1632 | unsigned int r_x = REGNO (x), r_y = REGNO (y); |
de12be17 JC |
1633 | rtx i_x, i_y; /* invariant relationships of X and Y */ |
1634 | ||
1635 | i_x = r_x >= reg_base_value_size ? 0 : alias_invariant[r_x]; | |
1636 | i_y = r_y >= reg_base_value_size ? 0 : alias_invariant[r_y]; | |
1637 | ||
1638 | if (i_x == 0 && i_y == 0) | |
1639 | break; | |
1640 | ||
1641 | if (! memrefs_conflict_p (xsize, i_x ? i_x : x, | |
1642 | ysize, i_y ? i_y : y, c)) | |
1643 | return 0; | |
1644 | } | |
1645 | break; | |
1646 | ||
1d300e19 KG |
1647 | default: |
1648 | break; | |
9ae8ffe7 JL |
1649 | } |
1650 | ||
1651 | /* Treat an access through an AND (e.g. a subword access on an Alpha) | |
56ee9281 RH |
1652 | as an access with indeterminate size. Assume that references |
1653 | besides AND are aligned, so if the size of the other reference is | |
1654 | at least as large as the alignment, assume no other overlap. */ | |
9ae8ffe7 | 1655 | if (GET_CODE (x) == AND && GET_CODE (XEXP (x, 1)) == CONST_INT) |
56ee9281 | 1656 | { |
02e3377d | 1657 | if (GET_CODE (y) == AND || ysize < -INTVAL (XEXP (x, 1))) |
56ee9281 RH |
1658 | xsize = -1; |
1659 | return memrefs_conflict_p (xsize, XEXP (x, 0), ysize, y, c); | |
1660 | } | |
9ae8ffe7 | 1661 | if (GET_CODE (y) == AND && GET_CODE (XEXP (y, 1)) == CONST_INT) |
c02f035f | 1662 | { |
56ee9281 | 1663 | /* ??? If we are indexing far enough into the array/structure, we |
c02f035f RH |
1664 | may yet be able to determine that we can not overlap. But we |
1665 | also need to that we are far enough from the end not to overlap | |
56ee9281 | 1666 | a following reference, so we do nothing with that for now. */ |
02e3377d | 1667 | if (GET_CODE (x) == AND || xsize < -INTVAL (XEXP (y, 1))) |
56ee9281 RH |
1668 | ysize = -1; |
1669 | return memrefs_conflict_p (xsize, x, ysize, XEXP (y, 0), c); | |
c02f035f | 1670 | } |
9ae8ffe7 | 1671 | |
b24ea077 JW |
1672 | if (GET_CODE (x) == ADDRESSOF) |
1673 | { | |
1674 | if (y == frame_pointer_rtx | |
1675 | || GET_CODE (y) == ADDRESSOF) | |
1676 | return xsize <= 0 || ysize <= 0; | |
1677 | } | |
1678 | if (GET_CODE (y) == ADDRESSOF) | |
1679 | { | |
1680 | if (x == frame_pointer_rtx) | |
1681 | return xsize <= 0 || ysize <= 0; | |
1682 | } | |
d982e46e | 1683 | |
9ae8ffe7 JL |
1684 | if (CONSTANT_P (x)) |
1685 | { | |
1686 | if (GET_CODE (x) == CONST_INT && GET_CODE (y) == CONST_INT) | |
1687 | { | |
1688 | c += (INTVAL (y) - INTVAL (x)); | |
c02f035f | 1689 | return (xsize <= 0 || ysize <= 0 |
9ae8ffe7 JL |
1690 | || (c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)); |
1691 | } | |
1692 | ||
1693 | if (GET_CODE (x) == CONST) | |
1694 | { | |
1695 | if (GET_CODE (y) == CONST) | |
1696 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), | |
1697 | ysize, canon_rtx (XEXP (y, 0)), c); | |
1698 | else | |
1699 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), | |
1700 | ysize, y, c); | |
1701 | } | |
1702 | if (GET_CODE (y) == CONST) | |
1703 | return memrefs_conflict_p (xsize, x, ysize, | |
1704 | canon_rtx (XEXP (y, 0)), c); | |
1705 | ||
1706 | if (CONSTANT_P (y)) | |
b949ea8b | 1707 | return (xsize <= 0 || ysize <= 0 |
c02f035f | 1708 | || (rtx_equal_for_memref_p (x, y) |
b949ea8b | 1709 | && ((c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)))); |
9ae8ffe7 JL |
1710 | |
1711 | return 1; | |
1712 | } | |
1713 | return 1; | |
1714 | } | |
1715 | ||
1716 | /* Functions to compute memory dependencies. | |
1717 | ||
1718 | Since we process the insns in execution order, we can build tables | |
1719 | to keep track of what registers are fixed (and not aliased), what registers | |
1720 | are varying in known ways, and what registers are varying in unknown | |
1721 | ways. | |
1722 | ||
1723 | If both memory references are volatile, then there must always be a | |
1724 | dependence between the two references, since their order can not be | |
1725 | changed. A volatile and non-volatile reference can be interchanged | |
1726 | though. | |
1727 | ||
dc1618bc RK |
1728 | A MEM_IN_STRUCT reference at a non-AND varying address can never |
1729 | conflict with a non-MEM_IN_STRUCT reference at a fixed address. We | |
1730 | also must allow AND addresses, because they may generate accesses | |
1731 | outside the object being referenced. This is used to generate | |
1732 | aligned addresses from unaligned addresses, for instance, the alpha | |
1733 | storeqi_unaligned pattern. */ | |
9ae8ffe7 JL |
1734 | |
1735 | /* Read dependence: X is read after read in MEM takes place. There can | |
1736 | only be a dependence here if both reads are volatile. */ | |
1737 | ||
1738 | int | |
1739 | read_dependence (mem, x) | |
1740 | rtx mem; | |
1741 | rtx x; | |
1742 | { | |
1743 | return MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem); | |
1744 | } | |
1745 | ||
c6df88cb MM |
1746 | /* Returns MEM1 if and only if MEM1 is a scalar at a fixed address and |
1747 | MEM2 is a reference to a structure at a varying address, or returns | |
1748 | MEM2 if vice versa. Otherwise, returns NULL_RTX. If a non-NULL | |
1749 | value is returned MEM1 and MEM2 can never alias. VARIES_P is used | |
1750 | to decide whether or not an address may vary; it should return | |
eab5c70a BS |
1751 | nonzero whenever variation is possible. |
1752 | MEM1_ADDR and MEM2_ADDR are the addresses of MEM1 and MEM2. */ | |
1753 | ||
2c72b78f | 1754 | static rtx |
eab5c70a BS |
1755 | fixed_scalar_and_varying_struct_p (mem1, mem2, mem1_addr, mem2_addr, varies_p) |
1756 | rtx mem1, mem2; | |
1757 | rtx mem1_addr, mem2_addr; | |
e38fe8e0 | 1758 | int (*varies_p) PARAMS ((rtx, int)); |
eab5c70a | 1759 | { |
3e0abe15 GK |
1760 | if (! flag_strict_aliasing) |
1761 | return NULL_RTX; | |
1762 | ||
c6df88cb | 1763 | if (MEM_SCALAR_P (mem1) && MEM_IN_STRUCT_P (mem2) |
e38fe8e0 | 1764 | && !varies_p (mem1_addr, 1) && varies_p (mem2_addr, 1)) |
c6df88cb MM |
1765 | /* MEM1 is a scalar at a fixed address; MEM2 is a struct at a |
1766 | varying address. */ | |
1767 | return mem1; | |
1768 | ||
1769 | if (MEM_IN_STRUCT_P (mem1) && MEM_SCALAR_P (mem2) | |
e38fe8e0 | 1770 | && varies_p (mem1_addr, 1) && !varies_p (mem2_addr, 1)) |
c6df88cb MM |
1771 | /* MEM2 is a scalar at a fixed address; MEM1 is a struct at a |
1772 | varying address. */ | |
1773 | return mem2; | |
1774 | ||
1775 | return NULL_RTX; | |
1776 | } | |
1777 | ||
1778 | /* Returns nonzero if something about the mode or address format MEM1 | |
1779 | indicates that it might well alias *anything*. */ | |
1780 | ||
2c72b78f | 1781 | static int |
c6df88cb MM |
1782 | aliases_everything_p (mem) |
1783 | rtx mem; | |
1784 | { | |
c6df88cb MM |
1785 | if (GET_CODE (XEXP (mem, 0)) == AND) |
1786 | /* If the address is an AND, its very hard to know at what it is | |
1787 | actually pointing. */ | |
1788 | return 1; | |
1789 | ||
1790 | return 0; | |
1791 | } | |
1792 | ||
998d7deb RH |
1793 | /* Return true if we can determine that the fields referenced cannot |
1794 | overlap for any pair of objects. */ | |
1795 | ||
1796 | static bool | |
1797 | nonoverlapping_component_refs_p (x, y) | |
1798 | tree x, y; | |
1799 | { | |
1800 | tree fieldx, fieldy, typex, typey, orig_y; | |
1801 | ||
1802 | do | |
1803 | { | |
1804 | /* The comparison has to be done at a common type, since we don't | |
d6a7951f | 1805 | know how the inheritance hierarchy works. */ |
998d7deb RH |
1806 | orig_y = y; |
1807 | do | |
1808 | { | |
1809 | fieldx = TREE_OPERAND (x, 1); | |
1810 | typex = DECL_FIELD_CONTEXT (fieldx); | |
1811 | ||
1812 | y = orig_y; | |
1813 | do | |
1814 | { | |
1815 | fieldy = TREE_OPERAND (y, 1); | |
1816 | typey = DECL_FIELD_CONTEXT (fieldy); | |
1817 | ||
1818 | if (typex == typey) | |
1819 | goto found; | |
1820 | ||
1821 | y = TREE_OPERAND (y, 0); | |
1822 | } | |
1823 | while (y && TREE_CODE (y) == COMPONENT_REF); | |
1824 | ||
1825 | x = TREE_OPERAND (x, 0); | |
1826 | } | |
1827 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
1828 | ||
1829 | /* Never found a common type. */ | |
1830 | return false; | |
1831 | ||
1832 | found: | |
1833 | /* If we're left with accessing different fields of a structure, | |
1834 | then no overlap. */ | |
1835 | if (TREE_CODE (typex) == RECORD_TYPE | |
1836 | && fieldx != fieldy) | |
1837 | return true; | |
1838 | ||
1839 | /* The comparison on the current field failed. If we're accessing | |
1840 | a very nested structure, look at the next outer level. */ | |
1841 | x = TREE_OPERAND (x, 0); | |
1842 | y = TREE_OPERAND (y, 0); | |
1843 | } | |
1844 | while (x && y | |
1845 | && TREE_CODE (x) == COMPONENT_REF | |
1846 | && TREE_CODE (y) == COMPONENT_REF); | |
1847 | ||
1848 | return false; | |
1849 | } | |
1850 | ||
1851 | /* Look at the bottom of the COMPONENT_REF list for a DECL, and return it. */ | |
1852 | ||
1853 | static tree | |
1854 | decl_for_component_ref (x) | |
1855 | tree x; | |
1856 | { | |
1857 | do | |
1858 | { | |
1859 | x = TREE_OPERAND (x, 0); | |
1860 | } | |
1861 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
1862 | ||
1863 | return x && DECL_P (x) ? x : NULL_TREE; | |
1864 | } | |
1865 | ||
1866 | /* Walk up the COMPONENT_REF list and adjust OFFSET to compensate for the | |
1867 | offset of the field reference. */ | |
1868 | ||
1869 | static rtx | |
1870 | adjust_offset_for_component_ref (x, offset) | |
1871 | tree x; | |
1872 | rtx offset; | |
1873 | { | |
1874 | HOST_WIDE_INT ioffset; | |
1875 | ||
1876 | if (! offset) | |
1877 | return NULL_RTX; | |
1878 | ||
1879 | ioffset = INTVAL (offset); | |
1880 | do | |
1881 | { | |
1882 | tree field = TREE_OPERAND (x, 1); | |
1883 | ||
1884 | if (! host_integerp (DECL_FIELD_OFFSET (field), 1)) | |
1885 | return NULL_RTX; | |
1886 | ioffset += (tree_low_cst (DECL_FIELD_OFFSET (field), 1) | |
1887 | + (tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1) | |
1888 | / BITS_PER_UNIT)); | |
1889 | ||
1890 | x = TREE_OPERAND (x, 0); | |
1891 | } | |
1892 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
1893 | ||
1894 | return GEN_INT (ioffset); | |
1895 | } | |
1896 | ||
1897 | /* Return nonzero if we can deterimine the exprs corresponding to memrefs | |
a4311dfe RK |
1898 | X and Y and they do not overlap. */ |
1899 | ||
1900 | static int | |
1901 | nonoverlapping_memrefs_p (x, y) | |
1902 | rtx x, y; | |
1903 | { | |
998d7deb | 1904 | tree exprx = MEM_EXPR (x), expry = MEM_EXPR (y); |
a4311dfe RK |
1905 | rtx rtlx, rtly; |
1906 | rtx basex, basey; | |
998d7deb | 1907 | rtx moffsetx, moffsety; |
a4311dfe RK |
1908 | HOST_WIDE_INT offsetx = 0, offsety = 0, sizex, sizey, tem; |
1909 | ||
998d7deb RH |
1910 | /* Unless both have exprs, we can't tell anything. */ |
1911 | if (exprx == 0 || expry == 0) | |
1912 | return 0; | |
1913 | ||
1914 | /* If both are field references, we may be able to determine something. */ | |
1915 | if (TREE_CODE (exprx) == COMPONENT_REF | |
1916 | && TREE_CODE (expry) == COMPONENT_REF | |
1917 | && nonoverlapping_component_refs_p (exprx, expry)) | |
1918 | return 1; | |
1919 | ||
1920 | /* If the field reference test failed, look at the DECLs involved. */ | |
1921 | moffsetx = MEM_OFFSET (x); | |
1922 | if (TREE_CODE (exprx) == COMPONENT_REF) | |
1923 | { | |
1924 | tree t = decl_for_component_ref (exprx); | |
1925 | if (! t) | |
1926 | return 0; | |
1927 | moffsetx = adjust_offset_for_component_ref (exprx, moffsetx); | |
1928 | exprx = t; | |
1929 | } | |
1930 | moffsety = MEM_OFFSET (y); | |
1931 | if (TREE_CODE (expry) == COMPONENT_REF) | |
1932 | { | |
1933 | tree t = decl_for_component_ref (expry); | |
1934 | if (! t) | |
1935 | return 0; | |
1936 | moffsety = adjust_offset_for_component_ref (expry, moffsety); | |
1937 | expry = t; | |
1938 | } | |
1939 | ||
1940 | if (! DECL_P (exprx) || ! DECL_P (expry)) | |
a4311dfe RK |
1941 | return 0; |
1942 | ||
998d7deb RH |
1943 | rtlx = DECL_RTL (exprx); |
1944 | rtly = DECL_RTL (expry); | |
a4311dfe | 1945 | |
1edcd60b RK |
1946 | /* If either RTL is not a MEM, it must be a REG or CONCAT, meaning they |
1947 | can't overlap unless they are the same because we never reuse that part | |
1948 | of the stack frame used for locals for spilled pseudos. */ | |
1949 | if ((GET_CODE (rtlx) != MEM || GET_CODE (rtly) != MEM) | |
1950 | && ! rtx_equal_p (rtlx, rtly)) | |
a4311dfe RK |
1951 | return 1; |
1952 | ||
1953 | /* Get the base and offsets of both decls. If either is a register, we | |
1954 | know both are and are the same, so use that as the base. The only | |
1955 | we can avoid overlap is if we can deduce that they are nonoverlapping | |
1956 | pieces of that decl, which is very rare. */ | |
1edcd60b | 1957 | basex = GET_CODE (rtlx) == MEM ? XEXP (rtlx, 0) : rtlx; |
a4311dfe RK |
1958 | if (GET_CODE (basex) == PLUS && GET_CODE (XEXP (basex, 1)) == CONST_INT) |
1959 | offsetx = INTVAL (XEXP (basex, 1)), basex = XEXP (basex, 0); | |
1960 | ||
1edcd60b | 1961 | basey = GET_CODE (rtly) == MEM ? XEXP (rtly, 0) : rtly; |
a4311dfe RK |
1962 | if (GET_CODE (basey) == PLUS && GET_CODE (XEXP (basey, 1)) == CONST_INT) |
1963 | offsety = INTVAL (XEXP (basey, 1)), basey = XEXP (basey, 0); | |
1964 | ||
d746694a RK |
1965 | /* If the bases are different, we know they do not overlap if both |
1966 | are constants or if one is a constant and the other a pointer into the | |
1967 | stack frame. Otherwise a different base means we can't tell if they | |
1968 | overlap or not. */ | |
1969 | if (! rtx_equal_p (basex, basey)) | |
1970 | return ((CONSTANT_P (basex) && CONSTANT_P (basey)) | |
1971 | || (CONSTANT_P (basex) && REG_P (basey) | |
a06ef755 | 1972 | && REGNO_PTR_FRAME_P (REGNO (basey))) |
d746694a | 1973 | || (CONSTANT_P (basey) && REG_P (basex) |
a06ef755 | 1974 | && REGNO_PTR_FRAME_P (REGNO (basex)))); |
a4311dfe | 1975 | |
998d7deb | 1976 | sizex = (GET_CODE (rtlx) != MEM ? (int) GET_MODE_SIZE (GET_MODE (rtlx)) |
a4311dfe RK |
1977 | : MEM_SIZE (rtlx) ? INTVAL (MEM_SIZE (rtlx)) |
1978 | : -1); | |
998d7deb | 1979 | sizey = (GET_CODE (rtly) != MEM ? (int) GET_MODE_SIZE (GET_MODE (rtly)) |
a4311dfe RK |
1980 | : MEM_SIZE (rtly) ? INTVAL (MEM_SIZE (rtly)) : |
1981 | -1); | |
1982 | ||
0af5bc3e RK |
1983 | /* If we have an offset for either memref, it can update the values computed |
1984 | above. */ | |
998d7deb RH |
1985 | if (moffsetx) |
1986 | offsetx += INTVAL (moffsetx), sizex -= INTVAL (moffsetx); | |
1987 | if (moffsety) | |
1988 | offsety += INTVAL (moffsety), sizey -= INTVAL (moffsety); | |
a4311dfe | 1989 | |
0af5bc3e | 1990 | /* If a memref has both a size and an offset, we can use the smaller size. |
efc981bb | 1991 | We can't do this if the offset isn't known because we must view this |
0af5bc3e | 1992 | memref as being anywhere inside the DECL's MEM. */ |
998d7deb | 1993 | if (MEM_SIZE (x) && moffsetx) |
a4311dfe | 1994 | sizex = INTVAL (MEM_SIZE (x)); |
998d7deb | 1995 | if (MEM_SIZE (y) && moffsety) |
a4311dfe RK |
1996 | sizey = INTVAL (MEM_SIZE (y)); |
1997 | ||
1998 | /* Put the values of the memref with the lower offset in X's values. */ | |
1999 | if (offsetx > offsety) | |
2000 | { | |
2001 | tem = offsetx, offsetx = offsety, offsety = tem; | |
2002 | tem = sizex, sizex = sizey, sizey = tem; | |
2003 | } | |
2004 | ||
2005 | /* If we don't know the size of the lower-offset value, we can't tell | |
2006 | if they conflict. Otherwise, we do the test. */ | |
2007 | return sizex >= 0 && offsety > offsetx + sizex; | |
2008 | } | |
2009 | ||
9ae8ffe7 JL |
2010 | /* True dependence: X is read after store in MEM takes place. */ |
2011 | ||
2012 | int | |
2013 | true_dependence (mem, mem_mode, x, varies) | |
2014 | rtx mem; | |
2015 | enum machine_mode mem_mode; | |
2016 | rtx x; | |
e38fe8e0 | 2017 | int (*varies) PARAMS ((rtx, int)); |
9ae8ffe7 | 2018 | { |
b3694847 | 2019 | rtx x_addr, mem_addr; |
49982682 | 2020 | rtx base; |
9ae8ffe7 JL |
2021 | |
2022 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) | |
2023 | return 1; | |
2024 | ||
41472af8 MM |
2025 | if (DIFFERENT_ALIAS_SETS_P (x, mem)) |
2026 | return 0; | |
2027 | ||
b949ea8b JW |
2028 | /* Unchanging memory can't conflict with non-unchanging memory. |
2029 | A non-unchanging read can conflict with a non-unchanging write. | |
2030 | An unchanging read can conflict with an unchanging write since | |
2031 | there may be a single store to this address to initialize it. | |
ec569656 RK |
2032 | Note that an unchanging store can conflict with a non-unchanging read |
2033 | since we have to make conservative assumptions when we have a | |
2034 | record with readonly fields and we are copying the whole thing. | |
b949ea8b JW |
2035 | Just fall through to the code below to resolve potential conflicts. |
2036 | This won't handle all cases optimally, but the possible performance | |
2037 | loss should be negligible. */ | |
ec569656 | 2038 | if (RTX_UNCHANGING_P (x) && ! RTX_UNCHANGING_P (mem)) |
9ae8ffe7 JL |
2039 | return 0; |
2040 | ||
a4311dfe RK |
2041 | if (nonoverlapping_memrefs_p (mem, x)) |
2042 | return 0; | |
2043 | ||
56ee9281 RH |
2044 | if (mem_mode == VOIDmode) |
2045 | mem_mode = GET_MODE (mem); | |
2046 | ||
eab5c70a BS |
2047 | x_addr = get_addr (XEXP (x, 0)); |
2048 | mem_addr = get_addr (XEXP (mem, 0)); | |
2049 | ||
55efb413 JW |
2050 | base = find_base_term (x_addr); |
2051 | if (base && (GET_CODE (base) == LABEL_REF | |
2052 | || (GET_CODE (base) == SYMBOL_REF | |
2053 | && CONSTANT_POOL_ADDRESS_P (base)))) | |
2054 | return 0; | |
2055 | ||
eab5c70a | 2056 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), mem_mode)) |
1c72c7f6 JC |
2057 | return 0; |
2058 | ||
eab5c70a BS |
2059 | x_addr = canon_rtx (x_addr); |
2060 | mem_addr = canon_rtx (mem_addr); | |
6e73e666 | 2061 | |
0211b6ab JW |
2062 | if (! memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr, |
2063 | SIZE_FOR_MODE (x), x_addr, 0)) | |
2064 | return 0; | |
2065 | ||
c6df88cb | 2066 | if (aliases_everything_p (x)) |
0211b6ab JW |
2067 | return 1; |
2068 | ||
f5143c46 | 2069 | /* We cannot use aliases_everything_p to test MEM, since we must look |
c6df88cb MM |
2070 | at MEM_MODE, rather than GET_MODE (MEM). */ |
2071 | if (mem_mode == QImode || GET_CODE (mem_addr) == AND) | |
a13d4ebf AM |
2072 | return 1; |
2073 | ||
2074 | /* In true_dependence we also allow BLKmode to alias anything. Why | |
2075 | don't we do this in anti_dependence and output_dependence? */ | |
2076 | if (mem_mode == BLKmode || GET_MODE (x) == BLKmode) | |
2077 | return 1; | |
2078 | ||
2079 | return ! fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, | |
2080 | varies); | |
2081 | } | |
2082 | ||
2083 | /* Canonical true dependence: X is read after store in MEM takes place. | |
f5143c46 | 2084 | Variant of true_dependence which assumes MEM has already been |
a13d4ebf AM |
2085 | canonicalized (hence we no longer do that here). |
2086 | The mem_addr argument has been added, since true_dependence computed | |
2087 | this value prior to canonicalizing. */ | |
2088 | ||
2089 | int | |
2090 | canon_true_dependence (mem, mem_mode, mem_addr, x, varies) | |
2091 | rtx mem, mem_addr, x; | |
2092 | enum machine_mode mem_mode; | |
2093 | int (*varies) PARAMS ((rtx, int)); | |
2094 | { | |
b3694847 | 2095 | rtx x_addr; |
a13d4ebf AM |
2096 | |
2097 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) | |
2098 | return 1; | |
2099 | ||
2100 | if (DIFFERENT_ALIAS_SETS_P (x, mem)) | |
2101 | return 0; | |
2102 | ||
2103 | /* If X is an unchanging read, then it can't possibly conflict with any | |
2104 | non-unchanging store. It may conflict with an unchanging write though, | |
2105 | because there may be a single store to this address to initialize it. | |
2106 | Just fall through to the code below to resolve the case where we have | |
2107 | both an unchanging read and an unchanging write. This won't handle all | |
2108 | cases optimally, but the possible performance loss should be | |
2109 | negligible. */ | |
2110 | if (RTX_UNCHANGING_P (x) && ! RTX_UNCHANGING_P (mem)) | |
2111 | return 0; | |
2112 | ||
a4311dfe RK |
2113 | if (nonoverlapping_memrefs_p (x, mem)) |
2114 | return 0; | |
2115 | ||
a13d4ebf AM |
2116 | x_addr = get_addr (XEXP (x, 0)); |
2117 | ||
2118 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), mem_mode)) | |
2119 | return 0; | |
2120 | ||
2121 | x_addr = canon_rtx (x_addr); | |
2122 | if (! memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr, | |
2123 | SIZE_FOR_MODE (x), x_addr, 0)) | |
2124 | return 0; | |
2125 | ||
2126 | if (aliases_everything_p (x)) | |
2127 | return 1; | |
2128 | ||
f5143c46 | 2129 | /* We cannot use aliases_everything_p to test MEM, since we must look |
a13d4ebf AM |
2130 | at MEM_MODE, rather than GET_MODE (MEM). */ |
2131 | if (mem_mode == QImode || GET_CODE (mem_addr) == AND) | |
c6df88cb | 2132 | return 1; |
0211b6ab | 2133 | |
c6df88cb MM |
2134 | /* In true_dependence we also allow BLKmode to alias anything. Why |
2135 | don't we do this in anti_dependence and output_dependence? */ | |
2136 | if (mem_mode == BLKmode || GET_MODE (x) == BLKmode) | |
2137 | return 1; | |
0211b6ab | 2138 | |
eab5c70a BS |
2139 | return ! fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, |
2140 | varies); | |
9ae8ffe7 JL |
2141 | } |
2142 | ||
c6df88cb MM |
2143 | /* Returns non-zero if a write to X might alias a previous read from |
2144 | (or, if WRITEP is non-zero, a write to) MEM. */ | |
9ae8ffe7 | 2145 | |
2c72b78f | 2146 | static int |
c6df88cb | 2147 | write_dependence_p (mem, x, writep) |
9ae8ffe7 JL |
2148 | rtx mem; |
2149 | rtx x; | |
c6df88cb | 2150 | int writep; |
9ae8ffe7 | 2151 | { |
6e73e666 | 2152 | rtx x_addr, mem_addr; |
c6df88cb | 2153 | rtx fixed_scalar; |
49982682 | 2154 | rtx base; |
6e73e666 | 2155 | |
9ae8ffe7 JL |
2156 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) |
2157 | return 1; | |
2158 | ||
eab5c70a BS |
2159 | if (DIFFERENT_ALIAS_SETS_P (x, mem)) |
2160 | return 0; | |
2161 | ||
b949ea8b JW |
2162 | /* Unchanging memory can't conflict with non-unchanging memory. */ |
2163 | if (RTX_UNCHANGING_P (x) != RTX_UNCHANGING_P (mem)) | |
2164 | return 0; | |
2165 | ||
9ae8ffe7 JL |
2166 | /* If MEM is an unchanging read, then it can't possibly conflict with |
2167 | the store to X, because there is at most one store to MEM, and it must | |
2168 | have occurred somewhere before MEM. */ | |
55efb413 JW |
2169 | if (! writep && RTX_UNCHANGING_P (mem)) |
2170 | return 0; | |
2171 | ||
a4311dfe RK |
2172 | if (nonoverlapping_memrefs_p (x, mem)) |
2173 | return 0; | |
2174 | ||
55efb413 JW |
2175 | x_addr = get_addr (XEXP (x, 0)); |
2176 | mem_addr = get_addr (XEXP (mem, 0)); | |
2177 | ||
49982682 JW |
2178 | if (! writep) |
2179 | { | |
55efb413 | 2180 | base = find_base_term (mem_addr); |
49982682 JW |
2181 | if (base && (GET_CODE (base) == LABEL_REF |
2182 | || (GET_CODE (base) == SYMBOL_REF | |
2183 | && CONSTANT_POOL_ADDRESS_P (base)))) | |
2184 | return 0; | |
2185 | } | |
2186 | ||
eab5c70a BS |
2187 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), |
2188 | GET_MODE (mem))) | |
41472af8 MM |
2189 | return 0; |
2190 | ||
eab5c70a BS |
2191 | x_addr = canon_rtx (x_addr); |
2192 | mem_addr = canon_rtx (mem_addr); | |
6e73e666 | 2193 | |
c6df88cb MM |
2194 | if (!memrefs_conflict_p (SIZE_FOR_MODE (mem), mem_addr, |
2195 | SIZE_FOR_MODE (x), x_addr, 0)) | |
2196 | return 0; | |
2197 | ||
2198 | fixed_scalar | |
eab5c70a BS |
2199 | = fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, |
2200 | rtx_addr_varies_p); | |
2201 | ||
c6df88cb MM |
2202 | return (!(fixed_scalar == mem && !aliases_everything_p (x)) |
2203 | && !(fixed_scalar == x && !aliases_everything_p (mem))); | |
2204 | } | |
2205 | ||
2206 | /* Anti dependence: X is written after read in MEM takes place. */ | |
2207 | ||
2208 | int | |
2209 | anti_dependence (mem, x) | |
2210 | rtx mem; | |
2211 | rtx x; | |
2212 | { | |
2213 | return write_dependence_p (mem, x, /*writep=*/0); | |
9ae8ffe7 JL |
2214 | } |
2215 | ||
2216 | /* Output dependence: X is written after store in MEM takes place. */ | |
2217 | ||
2218 | int | |
2219 | output_dependence (mem, x) | |
b3694847 SS |
2220 | rtx mem; |
2221 | rtx x; | |
9ae8ffe7 | 2222 | { |
c6df88cb | 2223 | return write_dependence_p (mem, x, /*writep=*/1); |
9ae8ffe7 JL |
2224 | } |
2225 | ||
bf6d9fd7 | 2226 | /* Returns non-zero if X mentions something which is not |
7790df19 JW |
2227 | local to the function and is not constant. */ |
2228 | ||
2229 | static int | |
bf6d9fd7 | 2230 | nonlocal_mentioned_p (x) |
7790df19 JW |
2231 | rtx x; |
2232 | { | |
2233 | rtx base; | |
b3694847 | 2234 | RTX_CODE code; |
7790df19 JW |
2235 | int regno; |
2236 | ||
2237 | code = GET_CODE (x); | |
2238 | ||
2239 | if (GET_RTX_CLASS (code) == 'i') | |
2240 | { | |
2a8f6b90 JH |
2241 | /* Constant functions can be constant if they don't use |
2242 | scratch memory used to mark function w/o side effects. */ | |
24a28584 | 2243 | if (code == CALL_INSN && CONST_OR_PURE_CALL_P (x)) |
2a8f6b90 JH |
2244 | { |
2245 | x = CALL_INSN_FUNCTION_USAGE (x); | |
f8cd4126 RK |
2246 | if (x == 0) |
2247 | return 0; | |
2a8f6b90 JH |
2248 | } |
2249 | else | |
2250 | x = PATTERN (x); | |
7790df19 JW |
2251 | code = GET_CODE (x); |
2252 | } | |
2253 | ||
2254 | switch (code) | |
2255 | { | |
2256 | case SUBREG: | |
2257 | if (GET_CODE (SUBREG_REG (x)) == REG) | |
2258 | { | |
2259 | /* Global registers are not local. */ | |
2260 | if (REGNO (SUBREG_REG (x)) < FIRST_PSEUDO_REGISTER | |
ddef6bc7 | 2261 | && global_regs[subreg_regno (x)]) |
7790df19 JW |
2262 | return 1; |
2263 | return 0; | |
2264 | } | |
2265 | break; | |
2266 | ||
2267 | case REG: | |
2268 | regno = REGNO (x); | |
2269 | /* Global registers are not local. */ | |
2270 | if (regno < FIRST_PSEUDO_REGISTER && global_regs[regno]) | |
2271 | return 1; | |
2272 | return 0; | |
2273 | ||
2274 | case SCRATCH: | |
2275 | case PC: | |
2276 | case CC0: | |
2277 | case CONST_INT: | |
2278 | case CONST_DOUBLE: | |
69ef87e2 | 2279 | case CONST_VECTOR: |
7790df19 JW |
2280 | case CONST: |
2281 | case LABEL_REF: | |
2282 | return 0; | |
2283 | ||
2284 | case SYMBOL_REF: | |
2285 | /* Constants in the function's constants pool are constant. */ | |
2286 | if (CONSTANT_POOL_ADDRESS_P (x)) | |
2287 | return 0; | |
2288 | return 1; | |
2289 | ||
2290 | case CALL: | |
bf6d9fd7 | 2291 | /* Non-constant calls and recursion are not local. */ |
7790df19 JW |
2292 | return 1; |
2293 | ||
2294 | case MEM: | |
2295 | /* Be overly conservative and consider any volatile memory | |
2296 | reference as not local. */ | |
2297 | if (MEM_VOLATILE_P (x)) | |
2298 | return 1; | |
2299 | base = find_base_term (XEXP (x, 0)); | |
2300 | if (base) | |
2301 | { | |
b3b5ad95 JL |
2302 | /* A Pmode ADDRESS could be a reference via the structure value |
2303 | address or static chain. Such memory references are nonlocal. | |
2304 | ||
2305 | Thus, we have to examine the contents of the ADDRESS to find | |
2306 | out if this is a local reference or not. */ | |
2307 | if (GET_CODE (base) == ADDRESS | |
2308 | && GET_MODE (base) == Pmode | |
2309 | && (XEXP (base, 0) == stack_pointer_rtx | |
2310 | || XEXP (base, 0) == arg_pointer_rtx | |
2311 | #if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM | |
2312 | || XEXP (base, 0) == hard_frame_pointer_rtx | |
2313 | #endif | |
2314 | || XEXP (base, 0) == frame_pointer_rtx)) | |
7790df19 JW |
2315 | return 0; |
2316 | /* Constants in the function's constant pool are constant. */ | |
2317 | if (GET_CODE (base) == SYMBOL_REF && CONSTANT_POOL_ADDRESS_P (base)) | |
2318 | return 0; | |
2319 | } | |
2320 | return 1; | |
2321 | ||
bf6d9fd7 | 2322 | case UNSPEC_VOLATILE: |
7790df19 | 2323 | case ASM_INPUT: |
7790df19 JW |
2324 | return 1; |
2325 | ||
bf6d9fd7 JW |
2326 | case ASM_OPERANDS: |
2327 | if (MEM_VOLATILE_P (x)) | |
2328 | return 1; | |
2329 | ||
2330 | /* FALLTHROUGH */ | |
2331 | ||
7790df19 JW |
2332 | default: |
2333 | break; | |
2334 | } | |
2335 | ||
2336 | /* Recursively scan the operands of this expression. */ | |
2337 | ||
2338 | { | |
b3694847 SS |
2339 | const char *fmt = GET_RTX_FORMAT (code); |
2340 | int i; | |
7790df19 JW |
2341 | |
2342 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
2343 | { | |
2a8f6b90 | 2344 | if (fmt[i] == 'e' && XEXP (x, i)) |
7790df19 | 2345 | { |
bf6d9fd7 | 2346 | if (nonlocal_mentioned_p (XEXP (x, i))) |
7790df19 JW |
2347 | return 1; |
2348 | } | |
d4757e6a | 2349 | else if (fmt[i] == 'E') |
7790df19 | 2350 | { |
b3694847 | 2351 | int j; |
7790df19 | 2352 | for (j = 0; j < XVECLEN (x, i); j++) |
bf6d9fd7 | 2353 | if (nonlocal_mentioned_p (XVECEXP (x, i, j))) |
7790df19 JW |
2354 | return 1; |
2355 | } | |
2356 | } | |
2357 | } | |
2358 | ||
2359 | return 0; | |
2360 | } | |
2361 | ||
2362 | /* Mark the function if it is constant. */ | |
2363 | ||
2364 | void | |
2365 | mark_constant_function () | |
2366 | { | |
2367 | rtx insn; | |
bf6d9fd7 | 2368 | int nonlocal_mentioned; |
7790df19 JW |
2369 | |
2370 | if (TREE_PUBLIC (current_function_decl) | |
2371 | || TREE_READONLY (current_function_decl) | |
bf6d9fd7 | 2372 | || DECL_IS_PURE (current_function_decl) |
7790df19 JW |
2373 | || TREE_THIS_VOLATILE (current_function_decl) |
2374 | || TYPE_MODE (TREE_TYPE (current_function_decl)) == VOIDmode) | |
2375 | return; | |
2376 | ||
e004f2f7 | 2377 | /* A loop might not return which counts as a side effect. */ |
0ecf09f9 | 2378 | if (mark_dfs_back_edges ()) |
e004f2f7 JW |
2379 | return; |
2380 | ||
bf6d9fd7 JW |
2381 | nonlocal_mentioned = 0; |
2382 | ||
2383 | init_alias_analysis (); | |
2384 | ||
7790df19 JW |
2385 | /* Determine if this is a constant function. */ |
2386 | ||
2387 | for (insn = get_insns (); insn; insn = NEXT_INSN (insn)) | |
bf6d9fd7 JW |
2388 | if (INSN_P (insn) && nonlocal_mentioned_p (insn)) |
2389 | { | |
2390 | nonlocal_mentioned = 1; | |
2391 | break; | |
2392 | } | |
2393 | ||
2394 | end_alias_analysis (); | |
7790df19 JW |
2395 | |
2396 | /* Mark the function. */ | |
2397 | ||
bf6d9fd7 JW |
2398 | if (! nonlocal_mentioned) |
2399 | TREE_READONLY (current_function_decl) = 1; | |
7790df19 JW |
2400 | } |
2401 | ||
6e73e666 JC |
2402 | |
2403 | static HARD_REG_SET argument_registers; | |
2404 | ||
2405 | void | |
2406 | init_alias_once () | |
2407 | { | |
b3694847 | 2408 | int i; |
6e73e666 JC |
2409 | |
2410 | #ifndef OUTGOING_REGNO | |
2411 | #define OUTGOING_REGNO(N) N | |
2412 | #endif | |
2413 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) | |
2414 | /* Check whether this register can hold an incoming pointer | |
2415 | argument. FUNCTION_ARG_REGNO_P tests outgoing register | |
ec5c56db | 2416 | numbers, so translate if necessary due to register windows. */ |
6e73e666 JC |
2417 | if (FUNCTION_ARG_REGNO_P (OUTGOING_REGNO (i)) |
2418 | && HARD_REGNO_MODE_OK (i, Pmode)) | |
2419 | SET_HARD_REG_BIT (argument_registers, i); | |
3932261a | 2420 | |
30f72379 | 2421 | alias_sets = splay_tree_new (splay_tree_compare_ints, 0, 0); |
6e73e666 JC |
2422 | } |
2423 | ||
c13e8210 MM |
2424 | /* Initialize the aliasing machinery. Initialize the REG_KNOWN_VALUE |
2425 | array. */ | |
2426 | ||
9ae8ffe7 JL |
2427 | void |
2428 | init_alias_analysis () | |
2429 | { | |
2430 | int maxreg = max_reg_num (); | |
ea64ef27 | 2431 | int changed, pass; |
b3694847 SS |
2432 | int i; |
2433 | unsigned int ui; | |
2434 | rtx insn; | |
9ae8ffe7 JL |
2435 | |
2436 | reg_known_value_size = maxreg; | |
2437 | ||
e05e2395 MM |
2438 | reg_known_value |
2439 | = (rtx *) xcalloc ((maxreg - FIRST_PSEUDO_REGISTER), sizeof (rtx)) | |
2440 | - FIRST_PSEUDO_REGISTER; | |
2441 | reg_known_equiv_p | |
2442 | = (char*) xcalloc ((maxreg - FIRST_PSEUDO_REGISTER), sizeof (char)) | |
9ae8ffe7 | 2443 | - FIRST_PSEUDO_REGISTER; |
9ae8ffe7 | 2444 | |
6e73e666 JC |
2445 | /* Overallocate reg_base_value to allow some growth during loop |
2446 | optimization. Loop unrolling can create a large number of | |
2447 | registers. */ | |
2448 | reg_base_value_size = maxreg * 2; | |
ac606739 | 2449 | reg_base_value = (rtx *) xcalloc (reg_base_value_size, sizeof (rtx)); |
1f8f4a0b | 2450 | ggc_add_rtx_root (reg_base_value, reg_base_value_size); |
ac606739 | 2451 | |
e05e2395 MM |
2452 | new_reg_base_value = (rtx *) xmalloc (reg_base_value_size * sizeof (rtx)); |
2453 | reg_seen = (char *) xmalloc (reg_base_value_size); | |
de12be17 JC |
2454 | if (! reload_completed && flag_unroll_loops) |
2455 | { | |
ac606739 | 2456 | /* ??? Why are we realloc'ing if we're just going to zero it? */ |
de12be17 JC |
2457 | alias_invariant = (rtx *)xrealloc (alias_invariant, |
2458 | reg_base_value_size * sizeof (rtx)); | |
961192e1 | 2459 | memset ((char *)alias_invariant, 0, reg_base_value_size * sizeof (rtx)); |
de12be17 | 2460 | } |
ec907dd8 JL |
2461 | |
2462 | /* The basic idea is that each pass through this loop will use the | |
2463 | "constant" information from the previous pass to propagate alias | |
2464 | information through another level of assignments. | |
2465 | ||
2466 | This could get expensive if the assignment chains are long. Maybe | |
2467 | we should throttle the number of iterations, possibly based on | |
6e73e666 | 2468 | the optimization level or flag_expensive_optimizations. |
ec907dd8 JL |
2469 | |
2470 | We could propagate more information in the first pass by making use | |
2471 | of REG_N_SETS to determine immediately that the alias information | |
ea64ef27 JL |
2472 | for a pseudo is "constant". |
2473 | ||
2474 | A program with an uninitialized variable can cause an infinite loop | |
2475 | here. Instead of doing a full dataflow analysis to detect such problems | |
2476 | we just cap the number of iterations for the loop. | |
2477 | ||
2478 | The state of the arrays for the set chain in question does not matter | |
2479 | since the program has undefined behavior. */ | |
6e73e666 | 2480 | |
ea64ef27 | 2481 | pass = 0; |
6e73e666 | 2482 | do |
ec907dd8 JL |
2483 | { |
2484 | /* Assume nothing will change this iteration of the loop. */ | |
2485 | changed = 0; | |
2486 | ||
ec907dd8 JL |
2487 | /* We want to assign the same IDs each iteration of this loop, so |
2488 | start counting from zero each iteration of the loop. */ | |
2489 | unique_id = 0; | |
2490 | ||
f5143c46 | 2491 | /* We're at the start of the function each iteration through the |
ec907dd8 JL |
2492 | loop, so we're copying arguments. */ |
2493 | copying_arguments = 1; | |
9ae8ffe7 | 2494 | |
6e73e666 | 2495 | /* Wipe the potential alias information clean for this pass. */ |
961192e1 | 2496 | memset ((char *) new_reg_base_value, 0, reg_base_value_size * sizeof (rtx)); |
8072f69c | 2497 | |
6e73e666 | 2498 | /* Wipe the reg_seen array clean. */ |
961192e1 | 2499 | memset ((char *) reg_seen, 0, reg_base_value_size); |
9ae8ffe7 | 2500 | |
6e73e666 JC |
2501 | /* Mark all hard registers which may contain an address. |
2502 | The stack, frame and argument pointers may contain an address. | |
2503 | An argument register which can hold a Pmode value may contain | |
2504 | an address even if it is not in BASE_REGS. | |
8072f69c | 2505 | |
6e73e666 JC |
2506 | The address expression is VOIDmode for an argument and |
2507 | Pmode for other registers. */ | |
2508 | ||
2509 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) | |
2510 | if (TEST_HARD_REG_BIT (argument_registers, i)) | |
38a448ca RH |
2511 | new_reg_base_value[i] = gen_rtx_ADDRESS (VOIDmode, |
2512 | gen_rtx_REG (Pmode, i)); | |
6e73e666 JC |
2513 | |
2514 | new_reg_base_value[STACK_POINTER_REGNUM] | |
38a448ca | 2515 | = gen_rtx_ADDRESS (Pmode, stack_pointer_rtx); |
6e73e666 | 2516 | new_reg_base_value[ARG_POINTER_REGNUM] |
38a448ca | 2517 | = gen_rtx_ADDRESS (Pmode, arg_pointer_rtx); |
6e73e666 | 2518 | new_reg_base_value[FRAME_POINTER_REGNUM] |
38a448ca | 2519 | = gen_rtx_ADDRESS (Pmode, frame_pointer_rtx); |
2a2c8203 | 2520 | #if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM |
6e73e666 | 2521 | new_reg_base_value[HARD_FRAME_POINTER_REGNUM] |
38a448ca | 2522 | = gen_rtx_ADDRESS (Pmode, hard_frame_pointer_rtx); |
2a2c8203 | 2523 | #endif |
ec907dd8 JL |
2524 | |
2525 | /* Walk the insns adding values to the new_reg_base_value array. */ | |
2526 | for (insn = get_insns (); insn; insn = NEXT_INSN (insn)) | |
9ae8ffe7 | 2527 | { |
2c3c49de | 2528 | if (INSN_P (insn)) |
ec907dd8 | 2529 | { |
6e73e666 | 2530 | rtx note, set; |
efc9bd41 RK |
2531 | |
2532 | #if defined (HAVE_prologue) || defined (HAVE_epilogue) | |
f5143c46 | 2533 | /* The prologue/epilogue insns are not threaded onto the |
657959ca JL |
2534 | insn chain until after reload has completed. Thus, |
2535 | there is no sense wasting time checking if INSN is in | |
2536 | the prologue/epilogue until after reload has completed. */ | |
2537 | if (reload_completed | |
2538 | && prologue_epilogue_contains (insn)) | |
efc9bd41 RK |
2539 | continue; |
2540 | #endif | |
2541 | ||
ec907dd8 JL |
2542 | /* If this insn has a noalias note, process it, Otherwise, |
2543 | scan for sets. A simple set will have no side effects | |
ec5c56db | 2544 | which could change the base value of any other register. */ |
6e73e666 | 2545 | |
ec907dd8 | 2546 | if (GET_CODE (PATTERN (insn)) == SET |
efc9bd41 RK |
2547 | && REG_NOTES (insn) != 0 |
2548 | && find_reg_note (insn, REG_NOALIAS, NULL_RTX)) | |
84832317 | 2549 | record_set (SET_DEST (PATTERN (insn)), NULL_RTX, NULL); |
ec907dd8 | 2550 | else |
84832317 | 2551 | note_stores (PATTERN (insn), record_set, NULL); |
6e73e666 JC |
2552 | |
2553 | set = single_set (insn); | |
2554 | ||
2555 | if (set != 0 | |
2556 | && GET_CODE (SET_DEST (set)) == REG | |
fb6754f0 | 2557 | && REGNO (SET_DEST (set)) >= FIRST_PSEUDO_REGISTER) |
6e73e666 | 2558 | { |
fb6754f0 | 2559 | unsigned int regno = REGNO (SET_DEST (set)); |
713f41f9 BS |
2560 | rtx src = SET_SRC (set); |
2561 | ||
2562 | if (REG_NOTES (insn) != 0 | |
2563 | && (((note = find_reg_note (insn, REG_EQUAL, 0)) != 0 | |
2564 | && REG_N_SETS (regno) == 1) | |
2565 | || (note = find_reg_note (insn, REG_EQUIV, NULL_RTX)) != 0) | |
2566 | && GET_CODE (XEXP (note, 0)) != EXPR_LIST | |
bb2cf916 | 2567 | && ! rtx_varies_p (XEXP (note, 0), 1) |
713f41f9 BS |
2568 | && ! reg_overlap_mentioned_p (SET_DEST (set), XEXP (note, 0))) |
2569 | { | |
2570 | reg_known_value[regno] = XEXP (note, 0); | |
2571 | reg_known_equiv_p[regno] = REG_NOTE_KIND (note) == REG_EQUIV; | |
2572 | } | |
2573 | else if (REG_N_SETS (regno) == 1 | |
2574 | && GET_CODE (src) == PLUS | |
2575 | && GET_CODE (XEXP (src, 0)) == REG | |
fb6754f0 BS |
2576 | && REGNO (XEXP (src, 0)) >= FIRST_PSEUDO_REGISTER |
2577 | && (reg_known_value[REGNO (XEXP (src, 0))]) | |
713f41f9 BS |
2578 | && GET_CODE (XEXP (src, 1)) == CONST_INT) |
2579 | { | |
2580 | rtx op0 = XEXP (src, 0); | |
bb2cf916 | 2581 | op0 = reg_known_value[REGNO (op0)]; |
713f41f9 | 2582 | reg_known_value[regno] |
ed8908e7 | 2583 | = plus_constant (op0, INTVAL (XEXP (src, 1))); |
713f41f9 BS |
2584 | reg_known_equiv_p[regno] = 0; |
2585 | } | |
2586 | else if (REG_N_SETS (regno) == 1 | |
2587 | && ! rtx_varies_p (src, 1)) | |
2588 | { | |
2589 | reg_known_value[regno] = src; | |
2590 | reg_known_equiv_p[regno] = 0; | |
2591 | } | |
6e73e666 | 2592 | } |
ec907dd8 JL |
2593 | } |
2594 | else if (GET_CODE (insn) == NOTE | |
2595 | && NOTE_LINE_NUMBER (insn) == NOTE_INSN_FUNCTION_BEG) | |
2596 | copying_arguments = 0; | |
6e73e666 | 2597 | } |
ec907dd8 | 2598 | |
6e73e666 | 2599 | /* Now propagate values from new_reg_base_value to reg_base_value. */ |
e51712db | 2600 | for (ui = 0; ui < reg_base_value_size; ui++) |
6e73e666 | 2601 | { |
e51712db KG |
2602 | if (new_reg_base_value[ui] |
2603 | && new_reg_base_value[ui] != reg_base_value[ui] | |
2604 | && ! rtx_equal_p (new_reg_base_value[ui], reg_base_value[ui])) | |
ec907dd8 | 2605 | { |
e51712db | 2606 | reg_base_value[ui] = new_reg_base_value[ui]; |
6e73e666 | 2607 | changed = 1; |
ec907dd8 | 2608 | } |
9ae8ffe7 | 2609 | } |
9ae8ffe7 | 2610 | } |
6e73e666 | 2611 | while (changed && ++pass < MAX_ALIAS_LOOP_PASSES); |
9ae8ffe7 JL |
2612 | |
2613 | /* Fill in the remaining entries. */ | |
2614 | for (i = FIRST_PSEUDO_REGISTER; i < maxreg; i++) | |
2615 | if (reg_known_value[i] == 0) | |
2616 | reg_known_value[i] = regno_reg_rtx[i]; | |
2617 | ||
9ae8ffe7 JL |
2618 | /* Simplify the reg_base_value array so that no register refers to |
2619 | another register, except to special registers indirectly through | |
2620 | ADDRESS expressions. | |
2621 | ||
2622 | In theory this loop can take as long as O(registers^2), but unless | |
2623 | there are very long dependency chains it will run in close to linear | |
ea64ef27 JL |
2624 | time. |
2625 | ||
2626 | This loop may not be needed any longer now that the main loop does | |
2627 | a better job at propagating alias information. */ | |
2628 | pass = 0; | |
9ae8ffe7 JL |
2629 | do |
2630 | { | |
2631 | changed = 0; | |
ea64ef27 | 2632 | pass++; |
e51712db | 2633 | for (ui = 0; ui < reg_base_value_size; ui++) |
9ae8ffe7 | 2634 | { |
e51712db | 2635 | rtx base = reg_base_value[ui]; |
9ae8ffe7 JL |
2636 | if (base && GET_CODE (base) == REG) |
2637 | { | |
fb6754f0 | 2638 | unsigned int base_regno = REGNO (base); |
e51712db KG |
2639 | if (base_regno == ui) /* register set from itself */ |
2640 | reg_base_value[ui] = 0; | |
9ae8ffe7 | 2641 | else |
e51712db | 2642 | reg_base_value[ui] = reg_base_value[base_regno]; |
9ae8ffe7 JL |
2643 | changed = 1; |
2644 | } | |
2645 | } | |
2646 | } | |
ea64ef27 | 2647 | while (changed && pass < MAX_ALIAS_LOOP_PASSES); |
9ae8ffe7 | 2648 | |
e05e2395 MM |
2649 | /* Clean up. */ |
2650 | free (new_reg_base_value); | |
ec907dd8 | 2651 | new_reg_base_value = 0; |
e05e2395 | 2652 | free (reg_seen); |
9ae8ffe7 JL |
2653 | reg_seen = 0; |
2654 | } | |
2655 | ||
2656 | void | |
2657 | end_alias_analysis () | |
2658 | { | |
e05e2395 | 2659 | free (reg_known_value + FIRST_PSEUDO_REGISTER); |
9ae8ffe7 | 2660 | reg_known_value = 0; |
ac606739 | 2661 | reg_known_value_size = 0; |
e05e2395 MM |
2662 | free (reg_known_equiv_p + FIRST_PSEUDO_REGISTER); |
2663 | reg_known_equiv_p = 0; | |
ac606739 GS |
2664 | if (reg_base_value) |
2665 | { | |
1f8f4a0b | 2666 | ggc_del_root (reg_base_value); |
ac606739 GS |
2667 | free (reg_base_value); |
2668 | reg_base_value = 0; | |
2669 | } | |
9ae8ffe7 | 2670 | reg_base_value_size = 0; |
de12be17 JC |
2671 | if (alias_invariant) |
2672 | { | |
ac606739 | 2673 | free (alias_invariant); |
de12be17 JC |
2674 | alias_invariant = 0; |
2675 | } | |
9ae8ffe7 | 2676 | } |