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9ae8ffe7 | 1 | /* Alias analysis for GNU C |
d9221e01 | 2 | Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004 |
1afdf91c | 3 | Free Software Foundation, Inc. |
9ae8ffe7 JL |
4 | Contributed by John Carr (jfc@mit.edu). |
5 | ||
1322177d | 6 | This file is part of GCC. |
9ae8ffe7 | 7 | |
1322177d LB |
8 | GCC is free software; you can redistribute it and/or modify it under |
9 | the terms of the GNU General Public License as published by the Free | |
10 | Software Foundation; either version 2, or (at your option) any later | |
11 | version. | |
9ae8ffe7 | 12 | |
1322177d LB |
13 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY |
14 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
15 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
16 | for more details. | |
9ae8ffe7 JL |
17 | |
18 | You should have received a copy of the GNU General Public License | |
1322177d LB |
19 | along with GCC; see the file COPYING. If not, write to the Free |
20 | Software Foundation, 59 Temple Place - Suite 330, Boston, MA | |
21 | 02111-1307, USA. */ | |
9ae8ffe7 JL |
22 | |
23 | #include "config.h" | |
670ee920 | 24 | #include "system.h" |
4977bab6 ZW |
25 | #include "coretypes.h" |
26 | #include "tm.h" | |
9ae8ffe7 | 27 | #include "rtl.h" |
7790df19 | 28 | #include "tree.h" |
6baf1cc8 | 29 | #include "tm_p.h" |
49ad7cfa | 30 | #include "function.h" |
9ae8ffe7 JL |
31 | #include "expr.h" |
32 | #include "regs.h" | |
33 | #include "hard-reg-set.h" | |
e004f2f7 | 34 | #include "basic-block.h" |
9ae8ffe7 | 35 | #include "flags.h" |
264fac34 | 36 | #include "output.h" |
2e107e9e | 37 | #include "toplev.h" |
eab5c70a | 38 | #include "cselib.h" |
3932261a | 39 | #include "splay-tree.h" |
ac606739 | 40 | #include "ggc.h" |
d23c55c2 | 41 | #include "langhooks.h" |
0d446150 | 42 | #include "timevar.h" |
ab780373 | 43 | #include "target.h" |
b255a036 | 44 | #include "cgraph.h" |
9ddb66ca | 45 | #include "varray.h" |
3932261a MM |
46 | |
47 | /* The alias sets assigned to MEMs assist the back-end in determining | |
48 | which MEMs can alias which other MEMs. In general, two MEMs in | |
ac3d9668 RK |
49 | different alias sets cannot alias each other, with one important |
50 | exception. Consider something like: | |
3932261a | 51 | |
01d28c3f | 52 | struct S { int i; double d; }; |
3932261a MM |
53 | |
54 | a store to an `S' can alias something of either type `int' or type | |
55 | `double'. (However, a store to an `int' cannot alias a `double' | |
56 | and vice versa.) We indicate this via a tree structure that looks | |
57 | like: | |
58 | struct S | |
59 | / \ | |
60 | / \ | |
61 | |/_ _\| | |
62 | int double | |
63 | ||
ac3d9668 RK |
64 | (The arrows are directed and point downwards.) |
65 | In this situation we say the alias set for `struct S' is the | |
66 | `superset' and that those for `int' and `double' are `subsets'. | |
67 | ||
3bdf5ad1 RK |
68 | To see whether two alias sets can point to the same memory, we must |
69 | see if either alias set is a subset of the other. We need not trace | |
95bd1dd7 | 70 | past immediate descendants, however, since we propagate all |
3bdf5ad1 | 71 | grandchildren up one level. |
3932261a MM |
72 | |
73 | Alias set zero is implicitly a superset of all other alias sets. | |
74 | However, this is no actual entry for alias set zero. It is an | |
75 | error to attempt to explicitly construct a subset of zero. */ | |
76 | ||
b604074c | 77 | struct alias_set_entry GTY(()) |
d4b60170 | 78 | { |
3932261a | 79 | /* The alias set number, as stored in MEM_ALIAS_SET. */ |
3bdf5ad1 | 80 | HOST_WIDE_INT alias_set; |
3932261a MM |
81 | |
82 | /* The children of the alias set. These are not just the immediate | |
95bd1dd7 | 83 | children, but, in fact, all descendants. So, if we have: |
3932261a | 84 | |
ca7fd9cd | 85 | struct T { struct S s; float f; } |
3932261a MM |
86 | |
87 | continuing our example above, the children here will be all of | |
88 | `int', `double', `float', and `struct S'. */ | |
b604074c | 89 | splay_tree GTY((param1_is (int), param2_is (int))) children; |
2bf105ab RK |
90 | |
91 | /* Nonzero if would have a child of zero: this effectively makes this | |
92 | alias set the same as alias set zero. */ | |
93 | int has_zero_child; | |
b604074c GK |
94 | }; |
95 | typedef struct alias_set_entry *alias_set_entry; | |
9ae8ffe7 | 96 | |
4682ae04 AJ |
97 | static int rtx_equal_for_memref_p (rtx, rtx); |
98 | static rtx find_symbolic_term (rtx); | |
4682ae04 AJ |
99 | static int memrefs_conflict_p (int, rtx, int, rtx, HOST_WIDE_INT); |
100 | static void record_set (rtx, rtx, void *); | |
101 | static int base_alias_check (rtx, rtx, enum machine_mode, | |
102 | enum machine_mode); | |
103 | static rtx find_base_value (rtx); | |
104 | static int mems_in_disjoint_alias_sets_p (rtx, rtx); | |
105 | static int insert_subset_children (splay_tree_node, void*); | |
106 | static tree find_base_decl (tree); | |
107 | static alias_set_entry get_alias_set_entry (HOST_WIDE_INT); | |
108 | static rtx fixed_scalar_and_varying_struct_p (rtx, rtx, rtx, rtx, | |
109 | int (*) (rtx, int)); | |
110 | static int aliases_everything_p (rtx); | |
111 | static bool nonoverlapping_component_refs_p (tree, tree); | |
112 | static tree decl_for_component_ref (tree); | |
113 | static rtx adjust_offset_for_component_ref (tree, rtx); | |
114 | static int nonoverlapping_memrefs_p (rtx, rtx); | |
d2399d75 | 115 | static int write_dependence_p (rtx, rtx, int, int); |
4682ae04 AJ |
116 | |
117 | static int nonlocal_mentioned_p_1 (rtx *, void *); | |
118 | static int nonlocal_mentioned_p (rtx); | |
119 | static int nonlocal_referenced_p_1 (rtx *, void *); | |
120 | static int nonlocal_referenced_p (rtx); | |
121 | static int nonlocal_set_p_1 (rtx *, void *); | |
122 | static int nonlocal_set_p (rtx); | |
123 | static void memory_modified_1 (rtx, rtx, void *); | |
9ae8ffe7 JL |
124 | |
125 | /* Set up all info needed to perform alias analysis on memory references. */ | |
126 | ||
d4b60170 | 127 | /* Returns the size in bytes of the mode of X. */ |
9ae8ffe7 JL |
128 | #define SIZE_FOR_MODE(X) (GET_MODE_SIZE (GET_MODE (X))) |
129 | ||
41472af8 | 130 | /* Returns nonzero if MEM1 and MEM2 do not alias because they are in |
264fac34 MM |
131 | different alias sets. We ignore alias sets in functions making use |
132 | of variable arguments because the va_arg macros on some systems are | |
133 | not legal ANSI C. */ | |
134 | #define DIFFERENT_ALIAS_SETS_P(MEM1, MEM2) \ | |
3932261a | 135 | mems_in_disjoint_alias_sets_p (MEM1, MEM2) |
41472af8 | 136 | |
ea64ef27 | 137 | /* Cap the number of passes we make over the insns propagating alias |
ac3d9668 | 138 | information through set chains. 10 is a completely arbitrary choice. */ |
ea64ef27 | 139 | #define MAX_ALIAS_LOOP_PASSES 10 |
ca7fd9cd | 140 | |
9ae8ffe7 JL |
141 | /* reg_base_value[N] gives an address to which register N is related. |
142 | If all sets after the first add or subtract to the current value | |
143 | or otherwise modify it so it does not point to a different top level | |
144 | object, reg_base_value[N] is equal to the address part of the source | |
2a2c8203 JC |
145 | of the first set. |
146 | ||
147 | A base address can be an ADDRESS, SYMBOL_REF, or LABEL_REF. ADDRESS | |
148 | expressions represent certain special values: function arguments and | |
ca7fd9cd | 149 | the stack, frame, and argument pointers. |
b3b5ad95 JL |
150 | |
151 | The contents of an ADDRESS is not normally used, the mode of the | |
152 | ADDRESS determines whether the ADDRESS is a function argument or some | |
153 | other special value. Pointer equality, not rtx_equal_p, determines whether | |
154 | two ADDRESS expressions refer to the same base address. | |
155 | ||
156 | The only use of the contents of an ADDRESS is for determining if the | |
157 | current function performs nonlocal memory memory references for the | |
158 | purposes of marking the function as a constant function. */ | |
2a2c8203 | 159 | |
c582d54a | 160 | static GTY(()) varray_type reg_base_value; |
ac606739 | 161 | static rtx *new_reg_base_value; |
c582d54a JH |
162 | |
163 | /* We preserve the copy of old array around to avoid amount of garbage | |
164 | produced. About 8% of garbage produced were attributed to this | |
165 | array. */ | |
166 | static GTY((deletable (""))) varray_type old_reg_base_value; | |
d4b60170 | 167 | |
bf1660a6 JL |
168 | /* Static hunks of RTL used by the aliasing code; these are initialized |
169 | once per function to avoid unnecessary RTL allocations. */ | |
170 | static GTY (()) rtx static_reg_base_value[FIRST_PSEUDO_REGISTER]; | |
171 | ||
9ae8ffe7 | 172 | #define REG_BASE_VALUE(X) \ |
c582d54a JH |
173 | (reg_base_value && REGNO (X) < VARRAY_SIZE (reg_base_value) \ |
174 | ? VARRAY_RTX (reg_base_value, REGNO (X)) : 0) | |
9ae8ffe7 | 175 | |
de12be17 JC |
176 | /* Vector of known invariant relationships between registers. Set in |
177 | loop unrolling. Indexed by register number, if nonzero the value | |
178 | is an expression describing this register in terms of another. | |
179 | ||
180 | The length of this array is REG_BASE_VALUE_SIZE. | |
181 | ||
182 | Because this array contains only pseudo registers it has no effect | |
183 | after reload. */ | |
184 | static rtx *alias_invariant; | |
c582d54a | 185 | unsigned int alias_invariant_size; |
de12be17 | 186 | |
c13e8210 MM |
187 | /* Vector indexed by N giving the initial (unchanging) value known for |
188 | pseudo-register N. This array is initialized in | |
189 | init_alias_analysis, and does not change until end_alias_analysis | |
190 | is called. */ | |
9ae8ffe7 JL |
191 | rtx *reg_known_value; |
192 | ||
193 | /* Indicates number of valid entries in reg_known_value. */ | |
770ae6cc | 194 | static unsigned int reg_known_value_size; |
9ae8ffe7 JL |
195 | |
196 | /* Vector recording for each reg_known_value whether it is due to a | |
197 | REG_EQUIV note. Future passes (viz., reload) may replace the | |
198 | pseudo with the equivalent expression and so we account for the | |
ac3d9668 RK |
199 | dependences that would be introduced if that happens. |
200 | ||
201 | The REG_EQUIV notes created in assign_parms may mention the arg | |
202 | pointer, and there are explicit insns in the RTL that modify the | |
203 | arg pointer. Thus we must ensure that such insns don't get | |
204 | scheduled across each other because that would invalidate the | |
205 | REG_EQUIV notes. One could argue that the REG_EQUIV notes are | |
206 | wrong, but solving the problem in the scheduler will likely give | |
207 | better code, so we do it here. */ | |
9ae8ffe7 JL |
208 | char *reg_known_equiv_p; |
209 | ||
2a2c8203 JC |
210 | /* True when scanning insns from the start of the rtl to the |
211 | NOTE_INSN_FUNCTION_BEG note. */ | |
83bbd9b6 | 212 | static bool copying_arguments; |
9ae8ffe7 | 213 | |
3932261a | 214 | /* The splay-tree used to store the various alias set entries. */ |
b604074c | 215 | static GTY ((param_is (struct alias_set_entry))) varray_type alias_sets; |
ac3d9668 | 216 | \f |
3932261a MM |
217 | /* Returns a pointer to the alias set entry for ALIAS_SET, if there is |
218 | such an entry, or NULL otherwise. */ | |
219 | ||
9ddb66ca | 220 | static inline alias_set_entry |
4682ae04 | 221 | get_alias_set_entry (HOST_WIDE_INT alias_set) |
3932261a | 222 | { |
9ddb66ca | 223 | return (alias_set_entry)VARRAY_GENERIC_PTR (alias_sets, alias_set); |
3932261a MM |
224 | } |
225 | ||
ac3d9668 RK |
226 | /* Returns nonzero if the alias sets for MEM1 and MEM2 are such that |
227 | the two MEMs cannot alias each other. */ | |
3932261a | 228 | |
9ddb66ca | 229 | static inline int |
4682ae04 | 230 | mems_in_disjoint_alias_sets_p (rtx mem1, rtx mem2) |
3932261a | 231 | { |
ca7fd9cd | 232 | #ifdef ENABLE_CHECKING |
3932261a MM |
233 | /* Perform a basic sanity check. Namely, that there are no alias sets |
234 | if we're not using strict aliasing. This helps to catch bugs | |
235 | whereby someone uses PUT_CODE, but doesn't clear MEM_ALIAS_SET, or | |
236 | where a MEM is allocated in some way other than by the use of | |
237 | gen_rtx_MEM, and the MEM_ALIAS_SET is not cleared. If we begin to | |
238 | use alias sets to indicate that spilled registers cannot alias each | |
239 | other, we might need to remove this check. */ | |
d4b60170 RK |
240 | if (! flag_strict_aliasing |
241 | && (MEM_ALIAS_SET (mem1) != 0 || MEM_ALIAS_SET (mem2) != 0)) | |
3932261a MM |
242 | abort (); |
243 | #endif | |
244 | ||
1da68f56 RK |
245 | return ! alias_sets_conflict_p (MEM_ALIAS_SET (mem1), MEM_ALIAS_SET (mem2)); |
246 | } | |
3932261a | 247 | |
1da68f56 RK |
248 | /* Insert the NODE into the splay tree given by DATA. Used by |
249 | record_alias_subset via splay_tree_foreach. */ | |
250 | ||
251 | static int | |
4682ae04 | 252 | insert_subset_children (splay_tree_node node, void *data) |
1da68f56 RK |
253 | { |
254 | splay_tree_insert ((splay_tree) data, node->key, node->value); | |
255 | ||
256 | return 0; | |
257 | } | |
258 | ||
259 | /* Return 1 if the two specified alias sets may conflict. */ | |
260 | ||
261 | int | |
4682ae04 | 262 | alias_sets_conflict_p (HOST_WIDE_INT set1, HOST_WIDE_INT set2) |
1da68f56 RK |
263 | { |
264 | alias_set_entry ase; | |
265 | ||
266 | /* If have no alias set information for one of the operands, we have | |
267 | to assume it can alias anything. */ | |
268 | if (set1 == 0 || set2 == 0 | |
269 | /* If the two alias sets are the same, they may alias. */ | |
270 | || set1 == set2) | |
271 | return 1; | |
3932261a | 272 | |
3bdf5ad1 | 273 | /* See if the first alias set is a subset of the second. */ |
1da68f56 | 274 | ase = get_alias_set_entry (set1); |
2bf105ab RK |
275 | if (ase != 0 |
276 | && (ase->has_zero_child | |
277 | || splay_tree_lookup (ase->children, | |
1da68f56 RK |
278 | (splay_tree_key) set2))) |
279 | return 1; | |
3932261a MM |
280 | |
281 | /* Now do the same, but with the alias sets reversed. */ | |
1da68f56 | 282 | ase = get_alias_set_entry (set2); |
2bf105ab RK |
283 | if (ase != 0 |
284 | && (ase->has_zero_child | |
285 | || splay_tree_lookup (ase->children, | |
1da68f56 RK |
286 | (splay_tree_key) set1))) |
287 | return 1; | |
3932261a | 288 | |
1da68f56 | 289 | /* The two alias sets are distinct and neither one is the |
3932261a | 290 | child of the other. Therefore, they cannot alias. */ |
1da68f56 | 291 | return 0; |
3932261a | 292 | } |
1da68f56 RK |
293 | \f |
294 | /* Return 1 if TYPE is a RECORD_TYPE, UNION_TYPE, or QUAL_UNION_TYPE and has | |
295 | has any readonly fields. If any of the fields have types that | |
296 | contain readonly fields, return true as well. */ | |
3932261a | 297 | |
1da68f56 | 298 | int |
4682ae04 | 299 | readonly_fields_p (tree type) |
3932261a | 300 | { |
1da68f56 RK |
301 | tree field; |
302 | ||
303 | if (TREE_CODE (type) != RECORD_TYPE && TREE_CODE (type) != UNION_TYPE | |
304 | && TREE_CODE (type) != QUAL_UNION_TYPE) | |
305 | return 0; | |
306 | ||
307 | for (field = TYPE_FIELDS (type); field != 0; field = TREE_CHAIN (field)) | |
308 | if (TREE_CODE (field) == FIELD_DECL | |
309 | && (TREE_READONLY (field) | |
310 | || readonly_fields_p (TREE_TYPE (field)))) | |
311 | return 1; | |
3932261a MM |
312 | |
313 | return 0; | |
314 | } | |
3bdf5ad1 | 315 | \f |
1da68f56 RK |
316 | /* Return 1 if any MEM object of type T1 will always conflict (using the |
317 | dependency routines in this file) with any MEM object of type T2. | |
318 | This is used when allocating temporary storage. If T1 and/or T2 are | |
319 | NULL_TREE, it means we know nothing about the storage. */ | |
320 | ||
321 | int | |
4682ae04 | 322 | objects_must_conflict_p (tree t1, tree t2) |
1da68f56 | 323 | { |
82d610ec RK |
324 | HOST_WIDE_INT set1, set2; |
325 | ||
e8ea2809 RK |
326 | /* If neither has a type specified, we don't know if they'll conflict |
327 | because we may be using them to store objects of various types, for | |
328 | example the argument and local variables areas of inlined functions. */ | |
981a4c34 | 329 | if (t1 == 0 && t2 == 0) |
e8ea2809 RK |
330 | return 0; |
331 | ||
66cce54d RH |
332 | /* If one or the other has readonly fields or is readonly, |
333 | then they may not conflict. */ | |
334 | if ((t1 != 0 && readonly_fields_p (t1)) | |
335 | || (t2 != 0 && readonly_fields_p (t2)) | |
a3b88570 MM |
336 | || (t1 != 0 && lang_hooks.honor_readonly && TYPE_READONLY (t1)) |
337 | || (t2 != 0 && lang_hooks.honor_readonly && TYPE_READONLY (t2))) | |
66cce54d RH |
338 | return 0; |
339 | ||
1da68f56 RK |
340 | /* If they are the same type, they must conflict. */ |
341 | if (t1 == t2 | |
342 | /* Likewise if both are volatile. */ | |
343 | || (t1 != 0 && TYPE_VOLATILE (t1) && t2 != 0 && TYPE_VOLATILE (t2))) | |
344 | return 1; | |
345 | ||
82d610ec RK |
346 | set1 = t1 ? get_alias_set (t1) : 0; |
347 | set2 = t2 ? get_alias_set (t2) : 0; | |
1da68f56 | 348 | |
82d610ec RK |
349 | /* Otherwise they conflict if they have no alias set or the same. We |
350 | can't simply use alias_sets_conflict_p here, because we must make | |
351 | sure that every subtype of t1 will conflict with every subtype of | |
352 | t2 for which a pair of subobjects of these respective subtypes | |
353 | overlaps on the stack. */ | |
354 | return set1 == 0 || set2 == 0 || set1 == set2; | |
1da68f56 RK |
355 | } |
356 | \f | |
3bdf5ad1 RK |
357 | /* T is an expression with pointer type. Find the DECL on which this |
358 | expression is based. (For example, in `a[i]' this would be `a'.) | |
359 | If there is no such DECL, or a unique decl cannot be determined, | |
f5143c46 | 360 | NULL_TREE is returned. */ |
3bdf5ad1 RK |
361 | |
362 | static tree | |
4682ae04 | 363 | find_base_decl (tree t) |
3bdf5ad1 RK |
364 | { |
365 | tree d0, d1, d2; | |
366 | ||
367 | if (t == 0 || t == error_mark_node || ! POINTER_TYPE_P (TREE_TYPE (t))) | |
368 | return 0; | |
369 | ||
370 | /* If this is a declaration, return it. */ | |
371 | if (TREE_CODE_CLASS (TREE_CODE (t)) == 'd') | |
372 | return t; | |
373 | ||
374 | /* Handle general expressions. It would be nice to deal with | |
375 | COMPONENT_REFs here. If we could tell that `a' and `b' were the | |
376 | same, then `a->f' and `b->f' are also the same. */ | |
377 | switch (TREE_CODE_CLASS (TREE_CODE (t))) | |
378 | { | |
379 | case '1': | |
380 | return find_base_decl (TREE_OPERAND (t, 0)); | |
381 | ||
382 | case '2': | |
383 | /* Return 0 if found in neither or both are the same. */ | |
384 | d0 = find_base_decl (TREE_OPERAND (t, 0)); | |
385 | d1 = find_base_decl (TREE_OPERAND (t, 1)); | |
386 | if (d0 == d1) | |
387 | return d0; | |
388 | else if (d0 == 0) | |
389 | return d1; | |
390 | else if (d1 == 0) | |
391 | return d0; | |
392 | else | |
393 | return 0; | |
394 | ||
395 | case '3': | |
396 | d0 = find_base_decl (TREE_OPERAND (t, 0)); | |
397 | d1 = find_base_decl (TREE_OPERAND (t, 1)); | |
3bdf5ad1 RK |
398 | d2 = find_base_decl (TREE_OPERAND (t, 2)); |
399 | ||
400 | /* Set any nonzero values from the last, then from the first. */ | |
401 | if (d1 == 0) d1 = d2; | |
402 | if (d0 == 0) d0 = d1; | |
403 | if (d1 == 0) d1 = d0; | |
404 | if (d2 == 0) d2 = d1; | |
405 | ||
406 | /* At this point all are nonzero or all are zero. If all three are the | |
407 | same, return it. Otherwise, return zero. */ | |
408 | return (d0 == d1 && d1 == d2) ? d0 : 0; | |
409 | ||
410 | default: | |
411 | return 0; | |
412 | } | |
413 | } | |
414 | ||
6e24b709 RK |
415 | /* Return 1 if all the nested component references handled by |
416 | get_inner_reference in T are such that we can address the object in T. */ | |
417 | ||
10b76d73 | 418 | int |
4682ae04 | 419 | can_address_p (tree t) |
6e24b709 RK |
420 | { |
421 | /* If we're at the end, it is vacuously addressable. */ | |
422 | if (! handled_component_p (t)) | |
423 | return 1; | |
424 | ||
425 | /* Bitfields are never addressable. */ | |
426 | else if (TREE_CODE (t) == BIT_FIELD_REF) | |
427 | return 0; | |
428 | ||
8ac61af7 RK |
429 | /* Fields are addressable unless they are marked as nonaddressable or |
430 | the containing type has alias set 0. */ | |
6e24b709 RK |
431 | else if (TREE_CODE (t) == COMPONENT_REF |
432 | && ! DECL_NONADDRESSABLE_P (TREE_OPERAND (t, 1)) | |
8ac61af7 | 433 | && get_alias_set (TREE_TYPE (TREE_OPERAND (t, 0))) != 0 |
6e24b709 RK |
434 | && can_address_p (TREE_OPERAND (t, 0))) |
435 | return 1; | |
436 | ||
8ac61af7 | 437 | /* Likewise for arrays. */ |
b4e3fabb | 438 | else if ((TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF) |
6e24b709 | 439 | && ! TYPE_NONALIASED_COMPONENT (TREE_TYPE (TREE_OPERAND (t, 0))) |
8ac61af7 | 440 | && get_alias_set (TREE_TYPE (TREE_OPERAND (t, 0))) != 0 |
6e24b709 RK |
441 | && can_address_p (TREE_OPERAND (t, 0))) |
442 | return 1; | |
443 | ||
444 | return 0; | |
445 | } | |
446 | ||
3bdf5ad1 RK |
447 | /* Return the alias set for T, which may be either a type or an |
448 | expression. Call language-specific routine for help, if needed. */ | |
449 | ||
450 | HOST_WIDE_INT | |
4682ae04 | 451 | get_alias_set (tree t) |
3bdf5ad1 RK |
452 | { |
453 | HOST_WIDE_INT set; | |
3bdf5ad1 RK |
454 | |
455 | /* If we're not doing any alias analysis, just assume everything | |
456 | aliases everything else. Also return 0 if this or its type is | |
457 | an error. */ | |
458 | if (! flag_strict_aliasing || t == error_mark_node | |
459 | || (! TYPE_P (t) | |
460 | && (TREE_TYPE (t) == 0 || TREE_TYPE (t) == error_mark_node))) | |
461 | return 0; | |
462 | ||
463 | /* We can be passed either an expression or a type. This and the | |
f47e9b4e RK |
464 | language-specific routine may make mutually-recursive calls to each other |
465 | to figure out what to do. At each juncture, we see if this is a tree | |
466 | that the language may need to handle specially. First handle things that | |
738cc472 | 467 | aren't types. */ |
f824e5c3 | 468 | if (! TYPE_P (t)) |
3bdf5ad1 | 469 | { |
738cc472 RK |
470 | tree inner = t; |
471 | tree placeholder_ptr = 0; | |
472 | ||
8ac61af7 RK |
473 | /* Remove any nops, then give the language a chance to do |
474 | something with this tree before we look at it. */ | |
475 | STRIP_NOPS (t); | |
476 | set = (*lang_hooks.get_alias_set) (t); | |
477 | if (set != -1) | |
478 | return set; | |
479 | ||
738cc472 | 480 | /* First see if the actual object referenced is an INDIRECT_REF from a |
8ac61af7 | 481 | restrict-qualified pointer or a "void *". Replace |
738cc472 | 482 | PLACEHOLDER_EXPRs. */ |
8ac61af7 | 483 | while (TREE_CODE (inner) == PLACEHOLDER_EXPR |
738cc472 RK |
484 | || handled_component_p (inner)) |
485 | { | |
486 | if (TREE_CODE (inner) == PLACEHOLDER_EXPR) | |
487 | inner = find_placeholder (inner, &placeholder_ptr); | |
488 | else | |
489 | inner = TREE_OPERAND (inner, 0); | |
8ac61af7 RK |
490 | |
491 | STRIP_NOPS (inner); | |
738cc472 RK |
492 | } |
493 | ||
494 | /* Check for accesses through restrict-qualified pointers. */ | |
495 | if (TREE_CODE (inner) == INDIRECT_REF) | |
496 | { | |
497 | tree decl = find_base_decl (TREE_OPERAND (inner, 0)); | |
498 | ||
499 | if (decl && DECL_POINTER_ALIAS_SET_KNOWN_P (decl)) | |
500 | { | |
e5837c07 | 501 | /* If we haven't computed the actual alias set, do it now. */ |
738cc472 RK |
502 | if (DECL_POINTER_ALIAS_SET (decl) == -2) |
503 | { | |
504 | /* No two restricted pointers can point at the same thing. | |
505 | However, a restricted pointer can point at the same thing | |
506 | as an unrestricted pointer, if that unrestricted pointer | |
507 | is based on the restricted pointer. So, we make the | |
508 | alias set for the restricted pointer a subset of the | |
509 | alias set for the type pointed to by the type of the | |
510 | decl. */ | |
511 | HOST_WIDE_INT pointed_to_alias_set | |
512 | = get_alias_set (TREE_TYPE (TREE_TYPE (decl))); | |
513 | ||
514 | if (pointed_to_alias_set == 0) | |
515 | /* It's not legal to make a subset of alias set zero. */ | |
e7844ffb | 516 | DECL_POINTER_ALIAS_SET (decl) = 0; |
738cc472 RK |
517 | else |
518 | { | |
519 | DECL_POINTER_ALIAS_SET (decl) = new_alias_set (); | |
ca7fd9cd KH |
520 | record_alias_subset (pointed_to_alias_set, |
521 | DECL_POINTER_ALIAS_SET (decl)); | |
738cc472 RK |
522 | } |
523 | } | |
524 | ||
525 | /* We use the alias set indicated in the declaration. */ | |
526 | return DECL_POINTER_ALIAS_SET (decl); | |
527 | } | |
528 | ||
529 | /* If we have an INDIRECT_REF via a void pointer, we don't | |
530 | know anything about what that might alias. */ | |
531 | else if (TREE_CODE (TREE_TYPE (inner)) == VOID_TYPE) | |
532 | return 0; | |
533 | } | |
534 | ||
535 | /* Otherwise, pick up the outermost object that we could have a pointer | |
536 | to, processing conversion and PLACEHOLDER_EXPR as above. */ | |
537 | placeholder_ptr = 0; | |
8ac61af7 | 538 | while (TREE_CODE (t) == PLACEHOLDER_EXPR |
f47e9b4e RK |
539 | || (handled_component_p (t) && ! can_address_p (t))) |
540 | { | |
f47e9b4e | 541 | if (TREE_CODE (t) == PLACEHOLDER_EXPR) |
738cc472 | 542 | t = find_placeholder (t, &placeholder_ptr); |
f47e9b4e RK |
543 | else |
544 | t = TREE_OPERAND (t, 0); | |
f824e5c3 | 545 | |
8ac61af7 RK |
546 | STRIP_NOPS (t); |
547 | } | |
f824e5c3 | 548 | |
738cc472 RK |
549 | /* If we've already determined the alias set for a decl, just return |
550 | it. This is necessary for C++ anonymous unions, whose component | |
551 | variables don't look like union members (boo!). */ | |
5755cd38 JM |
552 | if (TREE_CODE (t) == VAR_DECL |
553 | && DECL_RTL_SET_P (t) && GET_CODE (DECL_RTL (t)) == MEM) | |
554 | return MEM_ALIAS_SET (DECL_RTL (t)); | |
555 | ||
f824e5c3 RK |
556 | /* Now all we care about is the type. */ |
557 | t = TREE_TYPE (t); | |
3bdf5ad1 RK |
558 | } |
559 | ||
3bdf5ad1 RK |
560 | /* Variant qualifiers don't affect the alias set, so get the main |
561 | variant. If this is a type with a known alias set, return it. */ | |
562 | t = TYPE_MAIN_VARIANT (t); | |
738cc472 | 563 | if (TYPE_ALIAS_SET_KNOWN_P (t)) |
3bdf5ad1 RK |
564 | return TYPE_ALIAS_SET (t); |
565 | ||
566 | /* See if the language has special handling for this type. */ | |
8ac61af7 RK |
567 | set = (*lang_hooks.get_alias_set) (t); |
568 | if (set != -1) | |
738cc472 | 569 | return set; |
2bf105ab | 570 | |
3bdf5ad1 RK |
571 | /* There are no objects of FUNCTION_TYPE, so there's no point in |
572 | using up an alias set for them. (There are, of course, pointers | |
573 | and references to functions, but that's different.) */ | |
574 | else if (TREE_CODE (t) == FUNCTION_TYPE) | |
575 | set = 0; | |
74d86f4f RH |
576 | |
577 | /* Unless the language specifies otherwise, let vector types alias | |
578 | their components. This avoids some nasty type punning issues in | |
579 | normal usage. And indeed lets vectors be treated more like an | |
580 | array slice. */ | |
581 | else if (TREE_CODE (t) == VECTOR_TYPE) | |
582 | set = get_alias_set (TREE_TYPE (t)); | |
583 | ||
3bdf5ad1 RK |
584 | else |
585 | /* Otherwise make a new alias set for this type. */ | |
586 | set = new_alias_set (); | |
587 | ||
588 | TYPE_ALIAS_SET (t) = set; | |
2bf105ab RK |
589 | |
590 | /* If this is an aggregate type, we must record any component aliasing | |
591 | information. */ | |
1d79fd2c | 592 | if (AGGREGATE_TYPE_P (t) || TREE_CODE (t) == COMPLEX_TYPE) |
2bf105ab RK |
593 | record_component_aliases (t); |
594 | ||
3bdf5ad1 RK |
595 | return set; |
596 | } | |
597 | ||
598 | /* Return a brand-new alias set. */ | |
599 | ||
f103e34d GK |
600 | static GTY(()) HOST_WIDE_INT last_alias_set; |
601 | ||
3bdf5ad1 | 602 | HOST_WIDE_INT |
4682ae04 | 603 | new_alias_set (void) |
3bdf5ad1 | 604 | { |
3bdf5ad1 | 605 | if (flag_strict_aliasing) |
9ddb66ca | 606 | { |
3416f5c2 JH |
607 | if (!alias_sets) |
608 | VARRAY_GENERIC_PTR_INIT (alias_sets, 10, "alias sets"); | |
609 | else | |
610 | VARRAY_GROW (alias_sets, last_alias_set + 2); | |
9ddb66ca JH |
611 | return ++last_alias_set; |
612 | } | |
3bdf5ad1 RK |
613 | else |
614 | return 0; | |
615 | } | |
3932261a | 616 | |
01d28c3f JM |
617 | /* Indicate that things in SUBSET can alias things in SUPERSET, but that |
618 | not everything that aliases SUPERSET also aliases SUBSET. For example, | |
619 | in C, a store to an `int' can alias a load of a structure containing an | |
620 | `int', and vice versa. But it can't alias a load of a 'double' member | |
621 | of the same structure. Here, the structure would be the SUPERSET and | |
622 | `int' the SUBSET. This relationship is also described in the comment at | |
623 | the beginning of this file. | |
624 | ||
625 | This function should be called only once per SUPERSET/SUBSET pair. | |
3932261a MM |
626 | |
627 | It is illegal for SUPERSET to be zero; everything is implicitly a | |
628 | subset of alias set zero. */ | |
629 | ||
630 | void | |
4682ae04 | 631 | record_alias_subset (HOST_WIDE_INT superset, HOST_WIDE_INT subset) |
3932261a MM |
632 | { |
633 | alias_set_entry superset_entry; | |
634 | alias_set_entry subset_entry; | |
635 | ||
f47e9b4e RK |
636 | /* It is possible in complex type situations for both sets to be the same, |
637 | in which case we can ignore this operation. */ | |
638 | if (superset == subset) | |
639 | return; | |
640 | ||
3932261a MM |
641 | if (superset == 0) |
642 | abort (); | |
643 | ||
644 | superset_entry = get_alias_set_entry (superset); | |
ca7fd9cd | 645 | if (superset_entry == 0) |
3932261a MM |
646 | { |
647 | /* Create an entry for the SUPERSET, so that we have a place to | |
648 | attach the SUBSET. */ | |
b604074c | 649 | superset_entry = ggc_alloc (sizeof (struct alias_set_entry)); |
3932261a | 650 | superset_entry->alias_set = superset; |
ca7fd9cd | 651 | superset_entry->children |
b604074c | 652 | = splay_tree_new_ggc (splay_tree_compare_ints); |
570eb5c8 | 653 | superset_entry->has_zero_child = 0; |
9ddb66ca | 654 | VARRAY_GENERIC_PTR (alias_sets, superset) = superset_entry; |
3932261a MM |
655 | } |
656 | ||
2bf105ab RK |
657 | if (subset == 0) |
658 | superset_entry->has_zero_child = 1; | |
659 | else | |
660 | { | |
661 | subset_entry = get_alias_set_entry (subset); | |
662 | /* If there is an entry for the subset, enter all of its children | |
663 | (if they are not already present) as children of the SUPERSET. */ | |
ca7fd9cd | 664 | if (subset_entry) |
2bf105ab RK |
665 | { |
666 | if (subset_entry->has_zero_child) | |
667 | superset_entry->has_zero_child = 1; | |
d4b60170 | 668 | |
2bf105ab RK |
669 | splay_tree_foreach (subset_entry->children, insert_subset_children, |
670 | superset_entry->children); | |
671 | } | |
3932261a | 672 | |
2bf105ab | 673 | /* Enter the SUBSET itself as a child of the SUPERSET. */ |
ca7fd9cd | 674 | splay_tree_insert (superset_entry->children, |
2bf105ab RK |
675 | (splay_tree_key) subset, 0); |
676 | } | |
3932261a MM |
677 | } |
678 | ||
a0c33338 RK |
679 | /* Record that component types of TYPE, if any, are part of that type for |
680 | aliasing purposes. For record types, we only record component types | |
681 | for fields that are marked addressable. For array types, we always | |
682 | record the component types, so the front end should not call this | |
683 | function if the individual component aren't addressable. */ | |
684 | ||
685 | void | |
4682ae04 | 686 | record_component_aliases (tree type) |
a0c33338 | 687 | { |
3bdf5ad1 | 688 | HOST_WIDE_INT superset = get_alias_set (type); |
a0c33338 RK |
689 | tree field; |
690 | ||
691 | if (superset == 0) | |
692 | return; | |
693 | ||
694 | switch (TREE_CODE (type)) | |
695 | { | |
696 | case ARRAY_TYPE: | |
2bf105ab RK |
697 | if (! TYPE_NONALIASED_COMPONENT (type)) |
698 | record_alias_subset (superset, get_alias_set (TREE_TYPE (type))); | |
a0c33338 RK |
699 | break; |
700 | ||
701 | case RECORD_TYPE: | |
702 | case UNION_TYPE: | |
703 | case QUAL_UNION_TYPE: | |
6614fd40 | 704 | /* Recursively record aliases for the base classes, if there are any. */ |
61eece67 | 705 | if (TYPE_BINFO (type) != NULL && TYPE_BINFO_BASETYPES (type) != NULL) |
ca7fd9cd KH |
706 | { |
707 | int i; | |
708 | for (i = 0; i < TREE_VEC_LENGTH (TYPE_BINFO_BASETYPES (type)); i++) | |
709 | { | |
710 | tree binfo = TREE_VEC_ELT (TYPE_BINFO_BASETYPES (type), i); | |
711 | record_alias_subset (superset, | |
61eece67 | 712 | get_alias_set (BINFO_TYPE (binfo))); |
ca7fd9cd KH |
713 | } |
714 | } | |
a0c33338 | 715 | for (field = TYPE_FIELDS (type); field != 0; field = TREE_CHAIN (field)) |
b16a49a1 | 716 | if (TREE_CODE (field) == FIELD_DECL && ! DECL_NONADDRESSABLE_P (field)) |
2bf105ab | 717 | record_alias_subset (superset, get_alias_set (TREE_TYPE (field))); |
a0c33338 RK |
718 | break; |
719 | ||
1d79fd2c JW |
720 | case COMPLEX_TYPE: |
721 | record_alias_subset (superset, get_alias_set (TREE_TYPE (type))); | |
722 | break; | |
723 | ||
a0c33338 RK |
724 | default: |
725 | break; | |
726 | } | |
727 | } | |
728 | ||
3bdf5ad1 RK |
729 | /* Allocate an alias set for use in storing and reading from the varargs |
730 | spill area. */ | |
731 | ||
f103e34d GK |
732 | static GTY(()) HOST_WIDE_INT varargs_set = -1; |
733 | ||
3bdf5ad1 | 734 | HOST_WIDE_INT |
4682ae04 | 735 | get_varargs_alias_set (void) |
3bdf5ad1 | 736 | { |
f103e34d GK |
737 | if (varargs_set == -1) |
738 | varargs_set = new_alias_set (); | |
3bdf5ad1 | 739 | |
f103e34d | 740 | return varargs_set; |
3bdf5ad1 RK |
741 | } |
742 | ||
743 | /* Likewise, but used for the fixed portions of the frame, e.g., register | |
744 | save areas. */ | |
745 | ||
f103e34d GK |
746 | static GTY(()) HOST_WIDE_INT frame_set = -1; |
747 | ||
3bdf5ad1 | 748 | HOST_WIDE_INT |
4682ae04 | 749 | get_frame_alias_set (void) |
3bdf5ad1 | 750 | { |
f103e34d GK |
751 | if (frame_set == -1) |
752 | frame_set = new_alias_set (); | |
3bdf5ad1 | 753 | |
f103e34d | 754 | return frame_set; |
3bdf5ad1 RK |
755 | } |
756 | ||
2a2c8203 JC |
757 | /* Inside SRC, the source of a SET, find a base address. */ |
758 | ||
9ae8ffe7 | 759 | static rtx |
4682ae04 | 760 | find_base_value (rtx src) |
9ae8ffe7 | 761 | { |
713f41f9 | 762 | unsigned int regno; |
0aacc8ed | 763 | |
9ae8ffe7 JL |
764 | switch (GET_CODE (src)) |
765 | { | |
766 | case SYMBOL_REF: | |
767 | case LABEL_REF: | |
768 | return src; | |
769 | ||
770 | case REG: | |
fb6754f0 | 771 | regno = REGNO (src); |
d4b60170 | 772 | /* At the start of a function, argument registers have known base |
2a2c8203 JC |
773 | values which may be lost later. Returning an ADDRESS |
774 | expression here allows optimization based on argument values | |
775 | even when the argument registers are used for other purposes. */ | |
713f41f9 BS |
776 | if (regno < FIRST_PSEUDO_REGISTER && copying_arguments) |
777 | return new_reg_base_value[regno]; | |
73774bc7 | 778 | |
eaf407a5 | 779 | /* If a pseudo has a known base value, return it. Do not do this |
9b462c42 RH |
780 | for non-fixed hard regs since it can result in a circular |
781 | dependency chain for registers which have values at function entry. | |
eaf407a5 JL |
782 | |
783 | The test above is not sufficient because the scheduler may move | |
784 | a copy out of an arg reg past the NOTE_INSN_FUNCTION_BEGIN. */ | |
9b462c42 | 785 | if ((regno >= FIRST_PSEUDO_REGISTER || fixed_regs[regno]) |
c582d54a | 786 | && regno < VARRAY_SIZE (reg_base_value)) |
83bbd9b6 RH |
787 | { |
788 | /* If we're inside init_alias_analysis, use new_reg_base_value | |
789 | to reduce the number of relaxation iterations. */ | |
1afdf91c RH |
790 | if (new_reg_base_value && new_reg_base_value[regno] |
791 | && REG_N_SETS (regno) == 1) | |
83bbd9b6 RH |
792 | return new_reg_base_value[regno]; |
793 | ||
c582d54a JH |
794 | if (VARRAY_RTX (reg_base_value, regno)) |
795 | return VARRAY_RTX (reg_base_value, regno); | |
83bbd9b6 | 796 | } |
73774bc7 | 797 | |
e3f049a8 | 798 | return 0; |
9ae8ffe7 JL |
799 | |
800 | case MEM: | |
801 | /* Check for an argument passed in memory. Only record in the | |
802 | copying-arguments block; it is too hard to track changes | |
803 | otherwise. */ | |
804 | if (copying_arguments | |
805 | && (XEXP (src, 0) == arg_pointer_rtx | |
806 | || (GET_CODE (XEXP (src, 0)) == PLUS | |
807 | && XEXP (XEXP (src, 0), 0) == arg_pointer_rtx))) | |
38a448ca | 808 | return gen_rtx_ADDRESS (VOIDmode, src); |
9ae8ffe7 JL |
809 | return 0; |
810 | ||
811 | case CONST: | |
812 | src = XEXP (src, 0); | |
813 | if (GET_CODE (src) != PLUS && GET_CODE (src) != MINUS) | |
814 | break; | |
d4b60170 | 815 | |
ec5c56db | 816 | /* ... fall through ... */ |
2a2c8203 | 817 | |
9ae8ffe7 JL |
818 | case PLUS: |
819 | case MINUS: | |
2a2c8203 | 820 | { |
ec907dd8 JL |
821 | rtx temp, src_0 = XEXP (src, 0), src_1 = XEXP (src, 1); |
822 | ||
0134bf2d DE |
823 | /* If either operand is a REG that is a known pointer, then it |
824 | is the base. */ | |
825 | if (REG_P (src_0) && REG_POINTER (src_0)) | |
826 | return find_base_value (src_0); | |
827 | if (REG_P (src_1) && REG_POINTER (src_1)) | |
828 | return find_base_value (src_1); | |
829 | ||
ec907dd8 JL |
830 | /* If either operand is a REG, then see if we already have |
831 | a known value for it. */ | |
0134bf2d | 832 | if (REG_P (src_0)) |
ec907dd8 JL |
833 | { |
834 | temp = find_base_value (src_0); | |
d4b60170 | 835 | if (temp != 0) |
ec907dd8 JL |
836 | src_0 = temp; |
837 | } | |
838 | ||
0134bf2d | 839 | if (REG_P (src_1)) |
ec907dd8 JL |
840 | { |
841 | temp = find_base_value (src_1); | |
d4b60170 | 842 | if (temp!= 0) |
ec907dd8 JL |
843 | src_1 = temp; |
844 | } | |
2a2c8203 | 845 | |
0134bf2d DE |
846 | /* If either base is named object or a special address |
847 | (like an argument or stack reference), then use it for the | |
848 | base term. */ | |
849 | if (src_0 != 0 | |
850 | && (GET_CODE (src_0) == SYMBOL_REF | |
851 | || GET_CODE (src_0) == LABEL_REF | |
852 | || (GET_CODE (src_0) == ADDRESS | |
853 | && GET_MODE (src_0) != VOIDmode))) | |
854 | return src_0; | |
855 | ||
856 | if (src_1 != 0 | |
857 | && (GET_CODE (src_1) == SYMBOL_REF | |
858 | || GET_CODE (src_1) == LABEL_REF | |
859 | || (GET_CODE (src_1) == ADDRESS | |
860 | && GET_MODE (src_1) != VOIDmode))) | |
861 | return src_1; | |
862 | ||
d4b60170 | 863 | /* Guess which operand is the base address: |
ec907dd8 JL |
864 | If either operand is a symbol, then it is the base. If |
865 | either operand is a CONST_INT, then the other is the base. */ | |
d4b60170 | 866 | if (GET_CODE (src_1) == CONST_INT || CONSTANT_P (src_0)) |
2a2c8203 | 867 | return find_base_value (src_0); |
d4b60170 | 868 | else if (GET_CODE (src_0) == CONST_INT || CONSTANT_P (src_1)) |
ec907dd8 JL |
869 | return find_base_value (src_1); |
870 | ||
9ae8ffe7 | 871 | return 0; |
2a2c8203 JC |
872 | } |
873 | ||
874 | case LO_SUM: | |
875 | /* The standard form is (lo_sum reg sym) so look only at the | |
876 | second operand. */ | |
877 | return find_base_value (XEXP (src, 1)); | |
9ae8ffe7 JL |
878 | |
879 | case AND: | |
880 | /* If the second operand is constant set the base | |
ec5c56db | 881 | address to the first operand. */ |
2a2c8203 JC |
882 | if (GET_CODE (XEXP (src, 1)) == CONST_INT && INTVAL (XEXP (src, 1)) != 0) |
883 | return find_base_value (XEXP (src, 0)); | |
9ae8ffe7 JL |
884 | return 0; |
885 | ||
61f0131c R |
886 | case TRUNCATE: |
887 | if (GET_MODE_SIZE (GET_MODE (src)) < GET_MODE_SIZE (Pmode)) | |
888 | break; | |
889 | /* Fall through. */ | |
9ae8ffe7 | 890 | case HIGH: |
d288e53d DE |
891 | case PRE_INC: |
892 | case PRE_DEC: | |
893 | case POST_INC: | |
894 | case POST_DEC: | |
895 | case PRE_MODIFY: | |
896 | case POST_MODIFY: | |
2a2c8203 | 897 | return find_base_value (XEXP (src, 0)); |
1d300e19 | 898 | |
0aacc8ed RK |
899 | case ZERO_EXTEND: |
900 | case SIGN_EXTEND: /* used for NT/Alpha pointers */ | |
901 | { | |
902 | rtx temp = find_base_value (XEXP (src, 0)); | |
903 | ||
5ae6cd0d | 904 | if (temp != 0 && CONSTANT_P (temp)) |
0aacc8ed | 905 | temp = convert_memory_address (Pmode, temp); |
0aacc8ed RK |
906 | |
907 | return temp; | |
908 | } | |
909 | ||
1d300e19 KG |
910 | default: |
911 | break; | |
9ae8ffe7 JL |
912 | } |
913 | ||
914 | return 0; | |
915 | } | |
916 | ||
917 | /* Called from init_alias_analysis indirectly through note_stores. */ | |
918 | ||
d4b60170 | 919 | /* While scanning insns to find base values, reg_seen[N] is nonzero if |
9ae8ffe7 JL |
920 | register N has been set in this function. */ |
921 | static char *reg_seen; | |
922 | ||
13309a5f JC |
923 | /* Addresses which are known not to alias anything else are identified |
924 | by a unique integer. */ | |
ec907dd8 JL |
925 | static int unique_id; |
926 | ||
2a2c8203 | 927 | static void |
4682ae04 | 928 | record_set (rtx dest, rtx set, void *data ATTRIBUTE_UNUSED) |
9ae8ffe7 | 929 | { |
b3694847 | 930 | unsigned regno; |
9ae8ffe7 | 931 | rtx src; |
c28b4e40 | 932 | int n; |
9ae8ffe7 JL |
933 | |
934 | if (GET_CODE (dest) != REG) | |
935 | return; | |
936 | ||
fb6754f0 | 937 | regno = REGNO (dest); |
9ae8ffe7 | 938 | |
c582d54a | 939 | if (regno >= VARRAY_SIZE (reg_base_value)) |
ac606739 GS |
940 | abort (); |
941 | ||
c28b4e40 JW |
942 | /* If this spans multiple hard registers, then we must indicate that every |
943 | register has an unusable value. */ | |
944 | if (regno < FIRST_PSEUDO_REGISTER) | |
66fd46b6 | 945 | n = hard_regno_nregs[regno][GET_MODE (dest)]; |
c28b4e40 JW |
946 | else |
947 | n = 1; | |
948 | if (n != 1) | |
949 | { | |
950 | while (--n >= 0) | |
951 | { | |
952 | reg_seen[regno + n] = 1; | |
953 | new_reg_base_value[regno + n] = 0; | |
954 | } | |
955 | return; | |
956 | } | |
957 | ||
9ae8ffe7 JL |
958 | if (set) |
959 | { | |
960 | /* A CLOBBER wipes out any old value but does not prevent a previously | |
961 | unset register from acquiring a base address (i.e. reg_seen is not | |
962 | set). */ | |
963 | if (GET_CODE (set) == CLOBBER) | |
964 | { | |
ec907dd8 | 965 | new_reg_base_value[regno] = 0; |
9ae8ffe7 JL |
966 | return; |
967 | } | |
968 | src = SET_SRC (set); | |
969 | } | |
970 | else | |
971 | { | |
9ae8ffe7 JL |
972 | if (reg_seen[regno]) |
973 | { | |
ec907dd8 | 974 | new_reg_base_value[regno] = 0; |
9ae8ffe7 JL |
975 | return; |
976 | } | |
977 | reg_seen[regno] = 1; | |
38a448ca RH |
978 | new_reg_base_value[regno] = gen_rtx_ADDRESS (Pmode, |
979 | GEN_INT (unique_id++)); | |
9ae8ffe7 JL |
980 | return; |
981 | } | |
982 | ||
983 | /* This is not the first set. If the new value is not related to the | |
984 | old value, forget the base value. Note that the following code is | |
985 | not detected: | |
986 | extern int x, y; int *p = &x; p += (&y-&x); | |
987 | ANSI C does not allow computing the difference of addresses | |
988 | of distinct top level objects. */ | |
ec907dd8 | 989 | if (new_reg_base_value[regno]) |
9ae8ffe7 JL |
990 | switch (GET_CODE (src)) |
991 | { | |
2a2c8203 | 992 | case LO_SUM: |
9ae8ffe7 JL |
993 | case MINUS: |
994 | if (XEXP (src, 0) != dest && XEXP (src, 1) != dest) | |
ec907dd8 | 995 | new_reg_base_value[regno] = 0; |
9ae8ffe7 | 996 | break; |
61f0131c R |
997 | case PLUS: |
998 | /* If the value we add in the PLUS is also a valid base value, | |
999 | this might be the actual base value, and the original value | |
1000 | an index. */ | |
1001 | { | |
1002 | rtx other = NULL_RTX; | |
1003 | ||
1004 | if (XEXP (src, 0) == dest) | |
1005 | other = XEXP (src, 1); | |
1006 | else if (XEXP (src, 1) == dest) | |
1007 | other = XEXP (src, 0); | |
1008 | ||
1009 | if (! other || find_base_value (other)) | |
1010 | new_reg_base_value[regno] = 0; | |
1011 | break; | |
1012 | } | |
9ae8ffe7 JL |
1013 | case AND: |
1014 | if (XEXP (src, 0) != dest || GET_CODE (XEXP (src, 1)) != CONST_INT) | |
ec907dd8 | 1015 | new_reg_base_value[regno] = 0; |
9ae8ffe7 | 1016 | break; |
9ae8ffe7 | 1017 | default: |
ec907dd8 | 1018 | new_reg_base_value[regno] = 0; |
9ae8ffe7 JL |
1019 | break; |
1020 | } | |
1021 | /* If this is the first set of a register, record the value. */ | |
1022 | else if ((regno >= FIRST_PSEUDO_REGISTER || ! fixed_regs[regno]) | |
ec907dd8 JL |
1023 | && ! reg_seen[regno] && new_reg_base_value[regno] == 0) |
1024 | new_reg_base_value[regno] = find_base_value (src); | |
9ae8ffe7 JL |
1025 | |
1026 | reg_seen[regno] = 1; | |
1027 | } | |
1028 | ||
ac3d9668 RK |
1029 | /* Called from loop optimization when a new pseudo-register is |
1030 | created. It indicates that REGNO is being set to VAL. f INVARIANT | |
1031 | is true then this value also describes an invariant relationship | |
1032 | which can be used to deduce that two registers with unknown values | |
1033 | are different. */ | |
d4b60170 | 1034 | |
9ae8ffe7 | 1035 | void |
4682ae04 | 1036 | record_base_value (unsigned int regno, rtx val, int invariant) |
9ae8ffe7 | 1037 | { |
c582d54a | 1038 | if (invariant && alias_invariant && regno < alias_invariant_size) |
de12be17 JC |
1039 | alias_invariant[regno] = val; |
1040 | ||
c582d54a JH |
1041 | if (regno >= VARRAY_SIZE (reg_base_value)) |
1042 | VARRAY_GROW (reg_base_value, max_reg_num ()); | |
1043 | ||
9ae8ffe7 JL |
1044 | if (GET_CODE (val) == REG) |
1045 | { | |
c582d54a JH |
1046 | VARRAY_RTX (reg_base_value, regno) |
1047 | = REG_BASE_VALUE (val); | |
9ae8ffe7 JL |
1048 | return; |
1049 | } | |
c582d54a JH |
1050 | VARRAY_RTX (reg_base_value, regno) |
1051 | = find_base_value (val); | |
9ae8ffe7 JL |
1052 | } |
1053 | ||
43fe47ca JW |
1054 | /* Clear alias info for a register. This is used if an RTL transformation |
1055 | changes the value of a register. This is used in flow by AUTO_INC_DEC | |
1056 | optimizations. We don't need to clear reg_base_value, since flow only | |
1057 | changes the offset. */ | |
1058 | ||
1059 | void | |
4682ae04 | 1060 | clear_reg_alias_info (rtx reg) |
43fe47ca | 1061 | { |
4e1a4144 JW |
1062 | unsigned int regno = REGNO (reg); |
1063 | ||
1064 | if (regno < reg_known_value_size && regno >= FIRST_PSEUDO_REGISTER) | |
1065 | reg_known_value[regno] = reg; | |
43fe47ca JW |
1066 | } |
1067 | ||
db048faf MM |
1068 | /* Returns a canonical version of X, from the point of view alias |
1069 | analysis. (For example, if X is a MEM whose address is a register, | |
1070 | and the register has a known value (say a SYMBOL_REF), then a MEM | |
1071 | whose address is the SYMBOL_REF is returned.) */ | |
1072 | ||
1073 | rtx | |
4682ae04 | 1074 | canon_rtx (rtx x) |
9ae8ffe7 JL |
1075 | { |
1076 | /* Recursively look for equivalences. */ | |
fb6754f0 BS |
1077 | if (GET_CODE (x) == REG && REGNO (x) >= FIRST_PSEUDO_REGISTER |
1078 | && REGNO (x) < reg_known_value_size) | |
1079 | return reg_known_value[REGNO (x)] == x | |
1080 | ? x : canon_rtx (reg_known_value[REGNO (x)]); | |
9ae8ffe7 JL |
1081 | else if (GET_CODE (x) == PLUS) |
1082 | { | |
1083 | rtx x0 = canon_rtx (XEXP (x, 0)); | |
1084 | rtx x1 = canon_rtx (XEXP (x, 1)); | |
1085 | ||
1086 | if (x0 != XEXP (x, 0) || x1 != XEXP (x, 1)) | |
1087 | { | |
9ae8ffe7 | 1088 | if (GET_CODE (x0) == CONST_INT) |
ed8908e7 | 1089 | return plus_constant (x1, INTVAL (x0)); |
9ae8ffe7 | 1090 | else if (GET_CODE (x1) == CONST_INT) |
ed8908e7 | 1091 | return plus_constant (x0, INTVAL (x1)); |
38a448ca | 1092 | return gen_rtx_PLUS (GET_MODE (x), x0, x1); |
9ae8ffe7 JL |
1093 | } |
1094 | } | |
d4b60170 | 1095 | |
9ae8ffe7 JL |
1096 | /* This gives us much better alias analysis when called from |
1097 | the loop optimizer. Note we want to leave the original | |
1098 | MEM alone, but need to return the canonicalized MEM with | |
1099 | all the flags with their original values. */ | |
1100 | else if (GET_CODE (x) == MEM) | |
f1ec5147 | 1101 | x = replace_equiv_address_nv (x, canon_rtx (XEXP (x, 0))); |
d4b60170 | 1102 | |
9ae8ffe7 JL |
1103 | return x; |
1104 | } | |
1105 | ||
1106 | /* Return 1 if X and Y are identical-looking rtx's. | |
45183e03 | 1107 | Expect that X and Y has been already canonicalized. |
9ae8ffe7 JL |
1108 | |
1109 | We use the data in reg_known_value above to see if two registers with | |
1110 | different numbers are, in fact, equivalent. */ | |
1111 | ||
1112 | static int | |
4682ae04 | 1113 | rtx_equal_for_memref_p (rtx x, rtx y) |
9ae8ffe7 | 1114 | { |
b3694847 SS |
1115 | int i; |
1116 | int j; | |
1117 | enum rtx_code code; | |
1118 | const char *fmt; | |
9ae8ffe7 JL |
1119 | |
1120 | if (x == 0 && y == 0) | |
1121 | return 1; | |
1122 | if (x == 0 || y == 0) | |
1123 | return 0; | |
d4b60170 | 1124 | |
9ae8ffe7 JL |
1125 | if (x == y) |
1126 | return 1; | |
1127 | ||
1128 | code = GET_CODE (x); | |
1129 | /* Rtx's of different codes cannot be equal. */ | |
1130 | if (code != GET_CODE (y)) | |
1131 | return 0; | |
1132 | ||
1133 | /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. | |
1134 | (REG:SI x) and (REG:HI x) are NOT equivalent. */ | |
1135 | ||
1136 | if (GET_MODE (x) != GET_MODE (y)) | |
1137 | return 0; | |
1138 | ||
db048faf MM |
1139 | /* Some RTL can be compared without a recursive examination. */ |
1140 | switch (code) | |
1141 | { | |
1142 | case REG: | |
1143 | return REGNO (x) == REGNO (y); | |
1144 | ||
1145 | case LABEL_REF: | |
1146 | return XEXP (x, 0) == XEXP (y, 0); | |
ca7fd9cd | 1147 | |
db048faf MM |
1148 | case SYMBOL_REF: |
1149 | return XSTR (x, 0) == XSTR (y, 0); | |
1150 | ||
40e02b4a | 1151 | case VALUE: |
db048faf MM |
1152 | case CONST_INT: |
1153 | case CONST_DOUBLE: | |
1154 | /* There's no need to compare the contents of CONST_DOUBLEs or | |
1155 | CONST_INTs because pointer equality is a good enough | |
1156 | comparison for these nodes. */ | |
1157 | return 0; | |
1158 | ||
1159 | case ADDRESSOF: | |
831ecbd4 | 1160 | return (XINT (x, 1) == XINT (y, 1) |
45183e03 | 1161 | && rtx_equal_for_memref_p (XEXP (x, 0), |
4682ae04 | 1162 | XEXP (y, 0))); |
db048faf MM |
1163 | |
1164 | default: | |
1165 | break; | |
1166 | } | |
9ae8ffe7 | 1167 | |
45183e03 JH |
1168 | /* canon_rtx knows how to handle plus. No need to canonicalize. */ |
1169 | if (code == PLUS) | |
9ae8ffe7 JL |
1170 | return ((rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 0)) |
1171 | && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 1))) | |
1172 | || (rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 1)) | |
1173 | && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 0)))); | |
45183e03 JH |
1174 | /* For commutative operations, the RTX match if the operand match in any |
1175 | order. Also handle the simple binary and unary cases without a loop. */ | |
1176 | if (code == EQ || code == NE || GET_RTX_CLASS (code) == 'c') | |
1177 | { | |
1178 | rtx xop0 = canon_rtx (XEXP (x, 0)); | |
1179 | rtx yop0 = canon_rtx (XEXP (y, 0)); | |
1180 | rtx yop1 = canon_rtx (XEXP (y, 1)); | |
1181 | ||
1182 | return ((rtx_equal_for_memref_p (xop0, yop0) | |
1183 | && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), yop1)) | |
1184 | || (rtx_equal_for_memref_p (xop0, yop1) | |
1185 | && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), yop0))); | |
1186 | } | |
9ae8ffe7 | 1187 | else if (GET_RTX_CLASS (code) == '<' || GET_RTX_CLASS (code) == '2') |
45183e03 JH |
1188 | { |
1189 | return (rtx_equal_for_memref_p (canon_rtx (XEXP (x, 0)), | |
4682ae04 | 1190 | canon_rtx (XEXP (y, 0))) |
45183e03 JH |
1191 | && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), |
1192 | canon_rtx (XEXP (y, 1)))); | |
1193 | } | |
9ae8ffe7 | 1194 | else if (GET_RTX_CLASS (code) == '1') |
45183e03 | 1195 | return rtx_equal_for_memref_p (canon_rtx (XEXP (x, 0)), |
4682ae04 | 1196 | canon_rtx (XEXP (y, 0))); |
9ae8ffe7 JL |
1197 | |
1198 | /* Compare the elements. If any pair of corresponding elements | |
de12be17 JC |
1199 | fail to match, return 0 for the whole things. |
1200 | ||
1201 | Limit cases to types which actually appear in addresses. */ | |
9ae8ffe7 JL |
1202 | |
1203 | fmt = GET_RTX_FORMAT (code); | |
1204 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
1205 | { | |
1206 | switch (fmt[i]) | |
1207 | { | |
9ae8ffe7 JL |
1208 | case 'i': |
1209 | if (XINT (x, i) != XINT (y, i)) | |
1210 | return 0; | |
1211 | break; | |
1212 | ||
9ae8ffe7 JL |
1213 | case 'E': |
1214 | /* Two vectors must have the same length. */ | |
1215 | if (XVECLEN (x, i) != XVECLEN (y, i)) | |
1216 | return 0; | |
1217 | ||
1218 | /* And the corresponding elements must match. */ | |
1219 | for (j = 0; j < XVECLEN (x, i); j++) | |
45183e03 JH |
1220 | if (rtx_equal_for_memref_p (canon_rtx (XVECEXP (x, i, j)), |
1221 | canon_rtx (XVECEXP (y, i, j))) == 0) | |
9ae8ffe7 JL |
1222 | return 0; |
1223 | break; | |
1224 | ||
1225 | case 'e': | |
45183e03 JH |
1226 | if (rtx_equal_for_memref_p (canon_rtx (XEXP (x, i)), |
1227 | canon_rtx (XEXP (y, i))) == 0) | |
9ae8ffe7 JL |
1228 | return 0; |
1229 | break; | |
1230 | ||
3237ac18 AH |
1231 | /* This can happen for asm operands. */ |
1232 | case 's': | |
1233 | if (strcmp (XSTR (x, i), XSTR (y, i))) | |
1234 | return 0; | |
1235 | break; | |
1236 | ||
aee21ba9 JL |
1237 | /* This can happen for an asm which clobbers memory. */ |
1238 | case '0': | |
1239 | break; | |
1240 | ||
9ae8ffe7 JL |
1241 | /* It is believed that rtx's at this level will never |
1242 | contain anything but integers and other rtx's, | |
1243 | except for within LABEL_REFs and SYMBOL_REFs. */ | |
1244 | default: | |
1245 | abort (); | |
1246 | } | |
1247 | } | |
1248 | return 1; | |
1249 | } | |
1250 | ||
1251 | /* Given an rtx X, find a SYMBOL_REF or LABEL_REF within | |
1252 | X and return it, or return 0 if none found. */ | |
1253 | ||
1254 | static rtx | |
4682ae04 | 1255 | find_symbolic_term (rtx x) |
9ae8ffe7 | 1256 | { |
b3694847 SS |
1257 | int i; |
1258 | enum rtx_code code; | |
1259 | const char *fmt; | |
9ae8ffe7 JL |
1260 | |
1261 | code = GET_CODE (x); | |
1262 | if (code == SYMBOL_REF || code == LABEL_REF) | |
1263 | return x; | |
1264 | if (GET_RTX_CLASS (code) == 'o') | |
1265 | return 0; | |
1266 | ||
1267 | fmt = GET_RTX_FORMAT (code); | |
1268 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
1269 | { | |
1270 | rtx t; | |
1271 | ||
1272 | if (fmt[i] == 'e') | |
1273 | { | |
1274 | t = find_symbolic_term (XEXP (x, i)); | |
1275 | if (t != 0) | |
1276 | return t; | |
1277 | } | |
1278 | else if (fmt[i] == 'E') | |
1279 | break; | |
1280 | } | |
1281 | return 0; | |
1282 | } | |
1283 | ||
94f24ddc | 1284 | rtx |
4682ae04 | 1285 | find_base_term (rtx x) |
9ae8ffe7 | 1286 | { |
eab5c70a BS |
1287 | cselib_val *val; |
1288 | struct elt_loc_list *l; | |
1289 | ||
b949ea8b JW |
1290 | #if defined (FIND_BASE_TERM) |
1291 | /* Try machine-dependent ways to find the base term. */ | |
1292 | x = FIND_BASE_TERM (x); | |
1293 | #endif | |
1294 | ||
9ae8ffe7 JL |
1295 | switch (GET_CODE (x)) |
1296 | { | |
1297 | case REG: | |
1298 | return REG_BASE_VALUE (x); | |
1299 | ||
d288e53d DE |
1300 | case TRUNCATE: |
1301 | if (GET_MODE_SIZE (GET_MODE (x)) < GET_MODE_SIZE (Pmode)) | |
ca7fd9cd | 1302 | return 0; |
d288e53d | 1303 | /* Fall through. */ |
9ae8ffe7 | 1304 | case HIGH: |
6d849a2a JL |
1305 | case PRE_INC: |
1306 | case PRE_DEC: | |
1307 | case POST_INC: | |
1308 | case POST_DEC: | |
d288e53d DE |
1309 | case PRE_MODIFY: |
1310 | case POST_MODIFY: | |
6d849a2a JL |
1311 | return find_base_term (XEXP (x, 0)); |
1312 | ||
1abade85 RK |
1313 | case ZERO_EXTEND: |
1314 | case SIGN_EXTEND: /* Used for Alpha/NT pointers */ | |
1315 | { | |
1316 | rtx temp = find_base_term (XEXP (x, 0)); | |
1317 | ||
5ae6cd0d | 1318 | if (temp != 0 && CONSTANT_P (temp)) |
1abade85 | 1319 | temp = convert_memory_address (Pmode, temp); |
1abade85 RK |
1320 | |
1321 | return temp; | |
1322 | } | |
1323 | ||
eab5c70a BS |
1324 | case VALUE: |
1325 | val = CSELIB_VAL_PTR (x); | |
40e02b4a JH |
1326 | if (!val) |
1327 | return 0; | |
eab5c70a BS |
1328 | for (l = val->locs; l; l = l->next) |
1329 | if ((x = find_base_term (l->loc)) != 0) | |
1330 | return x; | |
1331 | return 0; | |
1332 | ||
9ae8ffe7 JL |
1333 | case CONST: |
1334 | x = XEXP (x, 0); | |
1335 | if (GET_CODE (x) != PLUS && GET_CODE (x) != MINUS) | |
1336 | return 0; | |
938d968e | 1337 | /* Fall through. */ |
9ae8ffe7 JL |
1338 | case LO_SUM: |
1339 | case PLUS: | |
1340 | case MINUS: | |
1341 | { | |
3c567fae JL |
1342 | rtx tmp1 = XEXP (x, 0); |
1343 | rtx tmp2 = XEXP (x, 1); | |
1344 | ||
f5143c46 | 1345 | /* This is a little bit tricky since we have to determine which of |
3c567fae JL |
1346 | the two operands represents the real base address. Otherwise this |
1347 | routine may return the index register instead of the base register. | |
1348 | ||
1349 | That may cause us to believe no aliasing was possible, when in | |
1350 | fact aliasing is possible. | |
1351 | ||
1352 | We use a few simple tests to guess the base register. Additional | |
1353 | tests can certainly be added. For example, if one of the operands | |
1354 | is a shift or multiply, then it must be the index register and the | |
1355 | other operand is the base register. */ | |
ca7fd9cd | 1356 | |
b949ea8b JW |
1357 | if (tmp1 == pic_offset_table_rtx && CONSTANT_P (tmp2)) |
1358 | return find_base_term (tmp2); | |
1359 | ||
3c567fae JL |
1360 | /* If either operand is known to be a pointer, then use it |
1361 | to determine the base term. */ | |
3502dc9c | 1362 | if (REG_P (tmp1) && REG_POINTER (tmp1)) |
3c567fae JL |
1363 | return find_base_term (tmp1); |
1364 | ||
3502dc9c | 1365 | if (REG_P (tmp2) && REG_POINTER (tmp2)) |
3c567fae JL |
1366 | return find_base_term (tmp2); |
1367 | ||
1368 | /* Neither operand was known to be a pointer. Go ahead and find the | |
1369 | base term for both operands. */ | |
1370 | tmp1 = find_base_term (tmp1); | |
1371 | tmp2 = find_base_term (tmp2); | |
1372 | ||
1373 | /* If either base term is named object or a special address | |
1374 | (like an argument or stack reference), then use it for the | |
1375 | base term. */ | |
d4b60170 | 1376 | if (tmp1 != 0 |
3c567fae JL |
1377 | && (GET_CODE (tmp1) == SYMBOL_REF |
1378 | || GET_CODE (tmp1) == LABEL_REF | |
1379 | || (GET_CODE (tmp1) == ADDRESS | |
1380 | && GET_MODE (tmp1) != VOIDmode))) | |
1381 | return tmp1; | |
1382 | ||
d4b60170 | 1383 | if (tmp2 != 0 |
3c567fae JL |
1384 | && (GET_CODE (tmp2) == SYMBOL_REF |
1385 | || GET_CODE (tmp2) == LABEL_REF | |
1386 | || (GET_CODE (tmp2) == ADDRESS | |
1387 | && GET_MODE (tmp2) != VOIDmode))) | |
1388 | return tmp2; | |
1389 | ||
1390 | /* We could not determine which of the two operands was the | |
1391 | base register and which was the index. So we can determine | |
1392 | nothing from the base alias check. */ | |
1393 | return 0; | |
9ae8ffe7 JL |
1394 | } |
1395 | ||
1396 | case AND: | |
d288e53d DE |
1397 | if (GET_CODE (XEXP (x, 1)) == CONST_INT && INTVAL (XEXP (x, 1)) != 0) |
1398 | return find_base_term (XEXP (x, 0)); | |
9ae8ffe7 JL |
1399 | return 0; |
1400 | ||
1401 | case SYMBOL_REF: | |
1402 | case LABEL_REF: | |
1403 | return x; | |
1404 | ||
d982e46e | 1405 | case ADDRESSOF: |
bb07060a | 1406 | return REG_BASE_VALUE (frame_pointer_rtx); |
d982e46e | 1407 | |
9ae8ffe7 JL |
1408 | default: |
1409 | return 0; | |
1410 | } | |
1411 | } | |
1412 | ||
1413 | /* Return 0 if the addresses X and Y are known to point to different | |
1414 | objects, 1 if they might be pointers to the same object. */ | |
1415 | ||
1416 | static int | |
4682ae04 AJ |
1417 | base_alias_check (rtx x, rtx y, enum machine_mode x_mode, |
1418 | enum machine_mode y_mode) | |
9ae8ffe7 JL |
1419 | { |
1420 | rtx x_base = find_base_term (x); | |
1421 | rtx y_base = find_base_term (y); | |
1422 | ||
1c72c7f6 JC |
1423 | /* If the address itself has no known base see if a known equivalent |
1424 | value has one. If either address still has no known base, nothing | |
1425 | is known about aliasing. */ | |
1426 | if (x_base == 0) | |
1427 | { | |
1428 | rtx x_c; | |
d4b60170 | 1429 | |
1c72c7f6 JC |
1430 | if (! flag_expensive_optimizations || (x_c = canon_rtx (x)) == x) |
1431 | return 1; | |
d4b60170 | 1432 | |
1c72c7f6 JC |
1433 | x_base = find_base_term (x_c); |
1434 | if (x_base == 0) | |
1435 | return 1; | |
1436 | } | |
9ae8ffe7 | 1437 | |
1c72c7f6 JC |
1438 | if (y_base == 0) |
1439 | { | |
1440 | rtx y_c; | |
1441 | if (! flag_expensive_optimizations || (y_c = canon_rtx (y)) == y) | |
1442 | return 1; | |
d4b60170 | 1443 | |
1c72c7f6 JC |
1444 | y_base = find_base_term (y_c); |
1445 | if (y_base == 0) | |
1446 | return 1; | |
1447 | } | |
1448 | ||
1449 | /* If the base addresses are equal nothing is known about aliasing. */ | |
1450 | if (rtx_equal_p (x_base, y_base)) | |
9ae8ffe7 JL |
1451 | return 1; |
1452 | ||
ca7fd9cd | 1453 | /* The base addresses of the read and write are different expressions. |
56ee9281 RH |
1454 | If they are both symbols and they are not accessed via AND, there is |
1455 | no conflict. We can bring knowledge of object alignment into play | |
1456 | here. For example, on alpha, "char a, b;" can alias one another, | |
1457 | though "char a; long b;" cannot. */ | |
9ae8ffe7 | 1458 | if (GET_CODE (x_base) != ADDRESS && GET_CODE (y_base) != ADDRESS) |
c02f035f | 1459 | { |
56ee9281 RH |
1460 | if (GET_CODE (x) == AND && GET_CODE (y) == AND) |
1461 | return 1; | |
1462 | if (GET_CODE (x) == AND | |
1463 | && (GET_CODE (XEXP (x, 1)) != CONST_INT | |
8fa2140d | 1464 | || (int) GET_MODE_UNIT_SIZE (y_mode) < -INTVAL (XEXP (x, 1)))) |
56ee9281 RH |
1465 | return 1; |
1466 | if (GET_CODE (y) == AND | |
1467 | && (GET_CODE (XEXP (y, 1)) != CONST_INT | |
8fa2140d | 1468 | || (int) GET_MODE_UNIT_SIZE (x_mode) < -INTVAL (XEXP (y, 1)))) |
56ee9281 | 1469 | return 1; |
b2972551 JL |
1470 | /* Differing symbols never alias. */ |
1471 | return 0; | |
c02f035f | 1472 | } |
9ae8ffe7 JL |
1473 | |
1474 | /* If one address is a stack reference there can be no alias: | |
1475 | stack references using different base registers do not alias, | |
1476 | a stack reference can not alias a parameter, and a stack reference | |
1477 | can not alias a global. */ | |
1478 | if ((GET_CODE (x_base) == ADDRESS && GET_MODE (x_base) == Pmode) | |
1479 | || (GET_CODE (y_base) == ADDRESS && GET_MODE (y_base) == Pmode)) | |
1480 | return 0; | |
1481 | ||
1482 | if (! flag_argument_noalias) | |
1483 | return 1; | |
1484 | ||
1485 | if (flag_argument_noalias > 1) | |
1486 | return 0; | |
1487 | ||
ec5c56db | 1488 | /* Weak noalias assertion (arguments are distinct, but may match globals). */ |
9ae8ffe7 JL |
1489 | return ! (GET_MODE (x_base) == VOIDmode && GET_MODE (y_base) == VOIDmode); |
1490 | } | |
1491 | ||
eab5c70a BS |
1492 | /* Convert the address X into something we can use. This is done by returning |
1493 | it unchanged unless it is a value; in the latter case we call cselib to get | |
1494 | a more useful rtx. */ | |
3bdf5ad1 | 1495 | |
a13d4ebf | 1496 | rtx |
4682ae04 | 1497 | get_addr (rtx x) |
eab5c70a BS |
1498 | { |
1499 | cselib_val *v; | |
1500 | struct elt_loc_list *l; | |
1501 | ||
1502 | if (GET_CODE (x) != VALUE) | |
1503 | return x; | |
1504 | v = CSELIB_VAL_PTR (x); | |
40e02b4a JH |
1505 | if (v) |
1506 | { | |
1507 | for (l = v->locs; l; l = l->next) | |
1508 | if (CONSTANT_P (l->loc)) | |
1509 | return l->loc; | |
1510 | for (l = v->locs; l; l = l->next) | |
1511 | if (GET_CODE (l->loc) != REG && GET_CODE (l->loc) != MEM) | |
1512 | return l->loc; | |
1513 | if (v->locs) | |
1514 | return v->locs->loc; | |
1515 | } | |
eab5c70a BS |
1516 | return x; |
1517 | } | |
1518 | ||
39cec1ac MH |
1519 | /* Return the address of the (N_REFS + 1)th memory reference to ADDR |
1520 | where SIZE is the size in bytes of the memory reference. If ADDR | |
1521 | is not modified by the memory reference then ADDR is returned. */ | |
1522 | ||
1523 | rtx | |
4682ae04 | 1524 | addr_side_effect_eval (rtx addr, int size, int n_refs) |
39cec1ac MH |
1525 | { |
1526 | int offset = 0; | |
ca7fd9cd | 1527 | |
39cec1ac MH |
1528 | switch (GET_CODE (addr)) |
1529 | { | |
1530 | case PRE_INC: | |
1531 | offset = (n_refs + 1) * size; | |
1532 | break; | |
1533 | case PRE_DEC: | |
1534 | offset = -(n_refs + 1) * size; | |
1535 | break; | |
1536 | case POST_INC: | |
1537 | offset = n_refs * size; | |
1538 | break; | |
1539 | case POST_DEC: | |
1540 | offset = -n_refs * size; | |
1541 | break; | |
1542 | ||
1543 | default: | |
1544 | return addr; | |
1545 | } | |
ca7fd9cd | 1546 | |
39cec1ac | 1547 | if (offset) |
45183e03 JH |
1548 | addr = gen_rtx_PLUS (GET_MODE (addr), XEXP (addr, 0), |
1549 | GEN_INT (offset)); | |
39cec1ac MH |
1550 | else |
1551 | addr = XEXP (addr, 0); | |
45183e03 | 1552 | addr = canon_rtx (addr); |
39cec1ac MH |
1553 | |
1554 | return addr; | |
1555 | } | |
1556 | ||
9ae8ffe7 JL |
1557 | /* Return nonzero if X and Y (memory addresses) could reference the |
1558 | same location in memory. C is an offset accumulator. When | |
1559 | C is nonzero, we are testing aliases between X and Y + C. | |
1560 | XSIZE is the size in bytes of the X reference, | |
1561 | similarly YSIZE is the size in bytes for Y. | |
45183e03 | 1562 | Expect that canon_rtx has been already called for X and Y. |
9ae8ffe7 JL |
1563 | |
1564 | If XSIZE or YSIZE is zero, we do not know the amount of memory being | |
1565 | referenced (the reference was BLKmode), so make the most pessimistic | |
1566 | assumptions. | |
1567 | ||
c02f035f RH |
1568 | If XSIZE or YSIZE is negative, we may access memory outside the object |
1569 | being referenced as a side effect. This can happen when using AND to | |
1570 | align memory references, as is done on the Alpha. | |
1571 | ||
9ae8ffe7 | 1572 | Nice to notice that varying addresses cannot conflict with fp if no |
0211b6ab | 1573 | local variables had their addresses taken, but that's too hard now. */ |
9ae8ffe7 | 1574 | |
9ae8ffe7 | 1575 | static int |
4682ae04 | 1576 | memrefs_conflict_p (int xsize, rtx x, int ysize, rtx y, HOST_WIDE_INT c) |
9ae8ffe7 | 1577 | { |
eab5c70a BS |
1578 | if (GET_CODE (x) == VALUE) |
1579 | x = get_addr (x); | |
1580 | if (GET_CODE (y) == VALUE) | |
1581 | y = get_addr (y); | |
9ae8ffe7 JL |
1582 | if (GET_CODE (x) == HIGH) |
1583 | x = XEXP (x, 0); | |
1584 | else if (GET_CODE (x) == LO_SUM) | |
1585 | x = XEXP (x, 1); | |
1586 | else | |
45183e03 | 1587 | x = addr_side_effect_eval (x, xsize, 0); |
9ae8ffe7 JL |
1588 | if (GET_CODE (y) == HIGH) |
1589 | y = XEXP (y, 0); | |
1590 | else if (GET_CODE (y) == LO_SUM) | |
1591 | y = XEXP (y, 1); | |
1592 | else | |
45183e03 | 1593 | y = addr_side_effect_eval (y, ysize, 0); |
9ae8ffe7 JL |
1594 | |
1595 | if (rtx_equal_for_memref_p (x, y)) | |
1596 | { | |
c02f035f | 1597 | if (xsize <= 0 || ysize <= 0) |
9ae8ffe7 JL |
1598 | return 1; |
1599 | if (c >= 0 && xsize > c) | |
1600 | return 1; | |
1601 | if (c < 0 && ysize+c > 0) | |
1602 | return 1; | |
1603 | return 0; | |
1604 | } | |
1605 | ||
6e73e666 JC |
1606 | /* This code used to check for conflicts involving stack references and |
1607 | globals but the base address alias code now handles these cases. */ | |
9ae8ffe7 JL |
1608 | |
1609 | if (GET_CODE (x) == PLUS) | |
1610 | { | |
1611 | /* The fact that X is canonicalized means that this | |
1612 | PLUS rtx is canonicalized. */ | |
1613 | rtx x0 = XEXP (x, 0); | |
1614 | rtx x1 = XEXP (x, 1); | |
1615 | ||
1616 | if (GET_CODE (y) == PLUS) | |
1617 | { | |
1618 | /* The fact that Y is canonicalized means that this | |
1619 | PLUS rtx is canonicalized. */ | |
1620 | rtx y0 = XEXP (y, 0); | |
1621 | rtx y1 = XEXP (y, 1); | |
1622 | ||
1623 | if (rtx_equal_for_memref_p (x1, y1)) | |
1624 | return memrefs_conflict_p (xsize, x0, ysize, y0, c); | |
1625 | if (rtx_equal_for_memref_p (x0, y0)) | |
1626 | return memrefs_conflict_p (xsize, x1, ysize, y1, c); | |
1627 | if (GET_CODE (x1) == CONST_INT) | |
63be02db JM |
1628 | { |
1629 | if (GET_CODE (y1) == CONST_INT) | |
1630 | return memrefs_conflict_p (xsize, x0, ysize, y0, | |
1631 | c - INTVAL (x1) + INTVAL (y1)); | |
1632 | else | |
1633 | return memrefs_conflict_p (xsize, x0, ysize, y, | |
1634 | c - INTVAL (x1)); | |
1635 | } | |
9ae8ffe7 JL |
1636 | else if (GET_CODE (y1) == CONST_INT) |
1637 | return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1)); | |
1638 | ||
6e73e666 | 1639 | return 1; |
9ae8ffe7 JL |
1640 | } |
1641 | else if (GET_CODE (x1) == CONST_INT) | |
1642 | return memrefs_conflict_p (xsize, x0, ysize, y, c - INTVAL (x1)); | |
1643 | } | |
1644 | else if (GET_CODE (y) == PLUS) | |
1645 | { | |
1646 | /* The fact that Y is canonicalized means that this | |
1647 | PLUS rtx is canonicalized. */ | |
1648 | rtx y0 = XEXP (y, 0); | |
1649 | rtx y1 = XEXP (y, 1); | |
1650 | ||
1651 | if (GET_CODE (y1) == CONST_INT) | |
1652 | return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1)); | |
1653 | else | |
1654 | return 1; | |
1655 | } | |
1656 | ||
1657 | if (GET_CODE (x) == GET_CODE (y)) | |
1658 | switch (GET_CODE (x)) | |
1659 | { | |
1660 | case MULT: | |
1661 | { | |
1662 | /* Handle cases where we expect the second operands to be the | |
1663 | same, and check only whether the first operand would conflict | |
1664 | or not. */ | |
1665 | rtx x0, y0; | |
1666 | rtx x1 = canon_rtx (XEXP (x, 1)); | |
1667 | rtx y1 = canon_rtx (XEXP (y, 1)); | |
1668 | if (! rtx_equal_for_memref_p (x1, y1)) | |
1669 | return 1; | |
1670 | x0 = canon_rtx (XEXP (x, 0)); | |
1671 | y0 = canon_rtx (XEXP (y, 0)); | |
1672 | if (rtx_equal_for_memref_p (x0, y0)) | |
1673 | return (xsize == 0 || ysize == 0 | |
1674 | || (c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)); | |
1675 | ||
1676 | /* Can't properly adjust our sizes. */ | |
1677 | if (GET_CODE (x1) != CONST_INT) | |
1678 | return 1; | |
1679 | xsize /= INTVAL (x1); | |
1680 | ysize /= INTVAL (x1); | |
1681 | c /= INTVAL (x1); | |
1682 | return memrefs_conflict_p (xsize, x0, ysize, y0, c); | |
1683 | } | |
1d300e19 | 1684 | |
de12be17 JC |
1685 | case REG: |
1686 | /* Are these registers known not to be equal? */ | |
1687 | if (alias_invariant) | |
1688 | { | |
e51712db | 1689 | unsigned int r_x = REGNO (x), r_y = REGNO (y); |
de12be17 JC |
1690 | rtx i_x, i_y; /* invariant relationships of X and Y */ |
1691 | ||
c582d54a JH |
1692 | i_x = r_x >= alias_invariant_size ? 0 : alias_invariant[r_x]; |
1693 | i_y = r_y >= alias_invariant_size ? 0 : alias_invariant[r_y]; | |
de12be17 JC |
1694 | |
1695 | if (i_x == 0 && i_y == 0) | |
1696 | break; | |
1697 | ||
1698 | if (! memrefs_conflict_p (xsize, i_x ? i_x : x, | |
1699 | ysize, i_y ? i_y : y, c)) | |
1700 | return 0; | |
1701 | } | |
1702 | break; | |
1703 | ||
1d300e19 KG |
1704 | default: |
1705 | break; | |
9ae8ffe7 JL |
1706 | } |
1707 | ||
1708 | /* Treat an access through an AND (e.g. a subword access on an Alpha) | |
ca7fd9cd | 1709 | as an access with indeterminate size. Assume that references |
56ee9281 RH |
1710 | besides AND are aligned, so if the size of the other reference is |
1711 | at least as large as the alignment, assume no other overlap. */ | |
9ae8ffe7 | 1712 | if (GET_CODE (x) == AND && GET_CODE (XEXP (x, 1)) == CONST_INT) |
56ee9281 | 1713 | { |
02e3377d | 1714 | if (GET_CODE (y) == AND || ysize < -INTVAL (XEXP (x, 1))) |
56ee9281 | 1715 | xsize = -1; |
45183e03 | 1716 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), ysize, y, c); |
56ee9281 | 1717 | } |
9ae8ffe7 | 1718 | if (GET_CODE (y) == AND && GET_CODE (XEXP (y, 1)) == CONST_INT) |
c02f035f | 1719 | { |
56ee9281 | 1720 | /* ??? If we are indexing far enough into the array/structure, we |
ca7fd9cd | 1721 | may yet be able to determine that we can not overlap. But we |
c02f035f | 1722 | also need to that we are far enough from the end not to overlap |
56ee9281 | 1723 | a following reference, so we do nothing with that for now. */ |
02e3377d | 1724 | if (GET_CODE (x) == AND || xsize < -INTVAL (XEXP (y, 1))) |
56ee9281 | 1725 | ysize = -1; |
45183e03 | 1726 | return memrefs_conflict_p (xsize, x, ysize, canon_rtx (XEXP (y, 0)), c); |
c02f035f | 1727 | } |
9ae8ffe7 | 1728 | |
b24ea077 JW |
1729 | if (GET_CODE (x) == ADDRESSOF) |
1730 | { | |
1731 | if (y == frame_pointer_rtx | |
1732 | || GET_CODE (y) == ADDRESSOF) | |
1733 | return xsize <= 0 || ysize <= 0; | |
1734 | } | |
1735 | if (GET_CODE (y) == ADDRESSOF) | |
1736 | { | |
1737 | if (x == frame_pointer_rtx) | |
1738 | return xsize <= 0 || ysize <= 0; | |
1739 | } | |
d982e46e | 1740 | |
9ae8ffe7 JL |
1741 | if (CONSTANT_P (x)) |
1742 | { | |
1743 | if (GET_CODE (x) == CONST_INT && GET_CODE (y) == CONST_INT) | |
1744 | { | |
1745 | c += (INTVAL (y) - INTVAL (x)); | |
c02f035f | 1746 | return (xsize <= 0 || ysize <= 0 |
9ae8ffe7 JL |
1747 | || (c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)); |
1748 | } | |
1749 | ||
1750 | if (GET_CODE (x) == CONST) | |
1751 | { | |
1752 | if (GET_CODE (y) == CONST) | |
1753 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), | |
1754 | ysize, canon_rtx (XEXP (y, 0)), c); | |
1755 | else | |
1756 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), | |
1757 | ysize, y, c); | |
1758 | } | |
1759 | if (GET_CODE (y) == CONST) | |
1760 | return memrefs_conflict_p (xsize, x, ysize, | |
1761 | canon_rtx (XEXP (y, 0)), c); | |
1762 | ||
1763 | if (CONSTANT_P (y)) | |
b949ea8b | 1764 | return (xsize <= 0 || ysize <= 0 |
c02f035f | 1765 | || (rtx_equal_for_memref_p (x, y) |
b949ea8b | 1766 | && ((c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)))); |
9ae8ffe7 JL |
1767 | |
1768 | return 1; | |
1769 | } | |
1770 | return 1; | |
1771 | } | |
1772 | ||
1773 | /* Functions to compute memory dependencies. | |
1774 | ||
1775 | Since we process the insns in execution order, we can build tables | |
1776 | to keep track of what registers are fixed (and not aliased), what registers | |
1777 | are varying in known ways, and what registers are varying in unknown | |
1778 | ways. | |
1779 | ||
1780 | If both memory references are volatile, then there must always be a | |
1781 | dependence between the two references, since their order can not be | |
1782 | changed. A volatile and non-volatile reference can be interchanged | |
ca7fd9cd | 1783 | though. |
9ae8ffe7 | 1784 | |
dc1618bc RK |
1785 | A MEM_IN_STRUCT reference at a non-AND varying address can never |
1786 | conflict with a non-MEM_IN_STRUCT reference at a fixed address. We | |
1787 | also must allow AND addresses, because they may generate accesses | |
1788 | outside the object being referenced. This is used to generate | |
1789 | aligned addresses from unaligned addresses, for instance, the alpha | |
1790 | storeqi_unaligned pattern. */ | |
9ae8ffe7 JL |
1791 | |
1792 | /* Read dependence: X is read after read in MEM takes place. There can | |
1793 | only be a dependence here if both reads are volatile. */ | |
1794 | ||
1795 | int | |
4682ae04 | 1796 | read_dependence (rtx mem, rtx x) |
9ae8ffe7 JL |
1797 | { |
1798 | return MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem); | |
1799 | } | |
1800 | ||
c6df88cb MM |
1801 | /* Returns MEM1 if and only if MEM1 is a scalar at a fixed address and |
1802 | MEM2 is a reference to a structure at a varying address, or returns | |
1803 | MEM2 if vice versa. Otherwise, returns NULL_RTX. If a non-NULL | |
1804 | value is returned MEM1 and MEM2 can never alias. VARIES_P is used | |
1805 | to decide whether or not an address may vary; it should return | |
eab5c70a BS |
1806 | nonzero whenever variation is possible. |
1807 | MEM1_ADDR and MEM2_ADDR are the addresses of MEM1 and MEM2. */ | |
ca7fd9cd | 1808 | |
2c72b78f | 1809 | static rtx |
4682ae04 AJ |
1810 | fixed_scalar_and_varying_struct_p (rtx mem1, rtx mem2, rtx mem1_addr, |
1811 | rtx mem2_addr, | |
1812 | int (*varies_p) (rtx, int)) | |
ca7fd9cd | 1813 | { |
3e0abe15 GK |
1814 | if (! flag_strict_aliasing) |
1815 | return NULL_RTX; | |
1816 | ||
ca7fd9cd | 1817 | if (MEM_SCALAR_P (mem1) && MEM_IN_STRUCT_P (mem2) |
e38fe8e0 | 1818 | && !varies_p (mem1_addr, 1) && varies_p (mem2_addr, 1)) |
c6df88cb MM |
1819 | /* MEM1 is a scalar at a fixed address; MEM2 is a struct at a |
1820 | varying address. */ | |
1821 | return mem1; | |
1822 | ||
ca7fd9cd | 1823 | if (MEM_IN_STRUCT_P (mem1) && MEM_SCALAR_P (mem2) |
e38fe8e0 | 1824 | && varies_p (mem1_addr, 1) && !varies_p (mem2_addr, 1)) |
c6df88cb MM |
1825 | /* MEM2 is a scalar at a fixed address; MEM1 is a struct at a |
1826 | varying address. */ | |
1827 | return mem2; | |
1828 | ||
1829 | return NULL_RTX; | |
1830 | } | |
1831 | ||
1832 | /* Returns nonzero if something about the mode or address format MEM1 | |
1833 | indicates that it might well alias *anything*. */ | |
1834 | ||
2c72b78f | 1835 | static int |
4682ae04 | 1836 | aliases_everything_p (rtx mem) |
c6df88cb | 1837 | { |
c6df88cb MM |
1838 | if (GET_CODE (XEXP (mem, 0)) == AND) |
1839 | /* If the address is an AND, its very hard to know at what it is | |
1840 | actually pointing. */ | |
1841 | return 1; | |
ca7fd9cd | 1842 | |
c6df88cb MM |
1843 | return 0; |
1844 | } | |
1845 | ||
998d7deb RH |
1846 | /* Return true if we can determine that the fields referenced cannot |
1847 | overlap for any pair of objects. */ | |
1848 | ||
1849 | static bool | |
4682ae04 | 1850 | nonoverlapping_component_refs_p (tree x, tree y) |
998d7deb RH |
1851 | { |
1852 | tree fieldx, fieldy, typex, typey, orig_y; | |
1853 | ||
1854 | do | |
1855 | { | |
1856 | /* The comparison has to be done at a common type, since we don't | |
d6a7951f | 1857 | know how the inheritance hierarchy works. */ |
998d7deb RH |
1858 | orig_y = y; |
1859 | do | |
1860 | { | |
1861 | fieldx = TREE_OPERAND (x, 1); | |
1862 | typex = DECL_FIELD_CONTEXT (fieldx); | |
1863 | ||
1864 | y = orig_y; | |
1865 | do | |
1866 | { | |
1867 | fieldy = TREE_OPERAND (y, 1); | |
1868 | typey = DECL_FIELD_CONTEXT (fieldy); | |
1869 | ||
1870 | if (typex == typey) | |
1871 | goto found; | |
1872 | ||
1873 | y = TREE_OPERAND (y, 0); | |
1874 | } | |
1875 | while (y && TREE_CODE (y) == COMPONENT_REF); | |
1876 | ||
1877 | x = TREE_OPERAND (x, 0); | |
1878 | } | |
1879 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
1880 | ||
1881 | /* Never found a common type. */ | |
1882 | return false; | |
1883 | ||
1884 | found: | |
1885 | /* If we're left with accessing different fields of a structure, | |
1886 | then no overlap. */ | |
1887 | if (TREE_CODE (typex) == RECORD_TYPE | |
1888 | && fieldx != fieldy) | |
1889 | return true; | |
1890 | ||
1891 | /* The comparison on the current field failed. If we're accessing | |
1892 | a very nested structure, look at the next outer level. */ | |
1893 | x = TREE_OPERAND (x, 0); | |
1894 | y = TREE_OPERAND (y, 0); | |
1895 | } | |
1896 | while (x && y | |
1897 | && TREE_CODE (x) == COMPONENT_REF | |
1898 | && TREE_CODE (y) == COMPONENT_REF); | |
ca7fd9cd | 1899 | |
998d7deb RH |
1900 | return false; |
1901 | } | |
1902 | ||
1903 | /* Look at the bottom of the COMPONENT_REF list for a DECL, and return it. */ | |
1904 | ||
1905 | static tree | |
4682ae04 | 1906 | decl_for_component_ref (tree x) |
998d7deb RH |
1907 | { |
1908 | do | |
1909 | { | |
1910 | x = TREE_OPERAND (x, 0); | |
1911 | } | |
1912 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
1913 | ||
1914 | return x && DECL_P (x) ? x : NULL_TREE; | |
1915 | } | |
1916 | ||
1917 | /* Walk up the COMPONENT_REF list and adjust OFFSET to compensate for the | |
1918 | offset of the field reference. */ | |
1919 | ||
1920 | static rtx | |
4682ae04 | 1921 | adjust_offset_for_component_ref (tree x, rtx offset) |
998d7deb RH |
1922 | { |
1923 | HOST_WIDE_INT ioffset; | |
1924 | ||
1925 | if (! offset) | |
1926 | return NULL_RTX; | |
1927 | ||
1928 | ioffset = INTVAL (offset); | |
ca7fd9cd | 1929 | do |
998d7deb RH |
1930 | { |
1931 | tree field = TREE_OPERAND (x, 1); | |
1932 | ||
1933 | if (! host_integerp (DECL_FIELD_OFFSET (field), 1)) | |
1934 | return NULL_RTX; | |
1935 | ioffset += (tree_low_cst (DECL_FIELD_OFFSET (field), 1) | |
1936 | + (tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1) | |
1937 | / BITS_PER_UNIT)); | |
1938 | ||
1939 | x = TREE_OPERAND (x, 0); | |
1940 | } | |
1941 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
1942 | ||
1943 | return GEN_INT (ioffset); | |
1944 | } | |
1945 | ||
95bd1dd7 | 1946 | /* Return nonzero if we can determine the exprs corresponding to memrefs |
a4311dfe RK |
1947 | X and Y and they do not overlap. */ |
1948 | ||
1949 | static int | |
4682ae04 | 1950 | nonoverlapping_memrefs_p (rtx x, rtx y) |
a4311dfe | 1951 | { |
998d7deb | 1952 | tree exprx = MEM_EXPR (x), expry = MEM_EXPR (y); |
a4311dfe RK |
1953 | rtx rtlx, rtly; |
1954 | rtx basex, basey; | |
998d7deb | 1955 | rtx moffsetx, moffsety; |
a4311dfe RK |
1956 | HOST_WIDE_INT offsetx = 0, offsety = 0, sizex, sizey, tem; |
1957 | ||
998d7deb RH |
1958 | /* Unless both have exprs, we can't tell anything. */ |
1959 | if (exprx == 0 || expry == 0) | |
1960 | return 0; | |
1961 | ||
1962 | /* If both are field references, we may be able to determine something. */ | |
1963 | if (TREE_CODE (exprx) == COMPONENT_REF | |
1964 | && TREE_CODE (expry) == COMPONENT_REF | |
1965 | && nonoverlapping_component_refs_p (exprx, expry)) | |
1966 | return 1; | |
1967 | ||
1968 | /* If the field reference test failed, look at the DECLs involved. */ | |
1969 | moffsetx = MEM_OFFSET (x); | |
1970 | if (TREE_CODE (exprx) == COMPONENT_REF) | |
1971 | { | |
1972 | tree t = decl_for_component_ref (exprx); | |
1973 | if (! t) | |
1974 | return 0; | |
1975 | moffsetx = adjust_offset_for_component_ref (exprx, moffsetx); | |
1976 | exprx = t; | |
1977 | } | |
c67a1cf6 RH |
1978 | else if (TREE_CODE (exprx) == INDIRECT_REF) |
1979 | { | |
1980 | exprx = TREE_OPERAND (exprx, 0); | |
1981 | if (flag_argument_noalias < 2 | |
1982 | || TREE_CODE (exprx) != PARM_DECL) | |
1983 | return 0; | |
1984 | } | |
1985 | ||
998d7deb RH |
1986 | moffsety = MEM_OFFSET (y); |
1987 | if (TREE_CODE (expry) == COMPONENT_REF) | |
1988 | { | |
1989 | tree t = decl_for_component_ref (expry); | |
1990 | if (! t) | |
1991 | return 0; | |
1992 | moffsety = adjust_offset_for_component_ref (expry, moffsety); | |
1993 | expry = t; | |
1994 | } | |
c67a1cf6 RH |
1995 | else if (TREE_CODE (expry) == INDIRECT_REF) |
1996 | { | |
1997 | expry = TREE_OPERAND (expry, 0); | |
1998 | if (flag_argument_noalias < 2 | |
1999 | || TREE_CODE (expry) != PARM_DECL) | |
2000 | return 0; | |
2001 | } | |
998d7deb RH |
2002 | |
2003 | if (! DECL_P (exprx) || ! DECL_P (expry)) | |
a4311dfe RK |
2004 | return 0; |
2005 | ||
998d7deb RH |
2006 | rtlx = DECL_RTL (exprx); |
2007 | rtly = DECL_RTL (expry); | |
a4311dfe | 2008 | |
1edcd60b RK |
2009 | /* If either RTL is not a MEM, it must be a REG or CONCAT, meaning they |
2010 | can't overlap unless they are the same because we never reuse that part | |
2011 | of the stack frame used for locals for spilled pseudos. */ | |
2012 | if ((GET_CODE (rtlx) != MEM || GET_CODE (rtly) != MEM) | |
2013 | && ! rtx_equal_p (rtlx, rtly)) | |
a4311dfe RK |
2014 | return 1; |
2015 | ||
2016 | /* Get the base and offsets of both decls. If either is a register, we | |
2017 | know both are and are the same, so use that as the base. The only | |
2018 | we can avoid overlap is if we can deduce that they are nonoverlapping | |
2019 | pieces of that decl, which is very rare. */ | |
1edcd60b | 2020 | basex = GET_CODE (rtlx) == MEM ? XEXP (rtlx, 0) : rtlx; |
a4311dfe RK |
2021 | if (GET_CODE (basex) == PLUS && GET_CODE (XEXP (basex, 1)) == CONST_INT) |
2022 | offsetx = INTVAL (XEXP (basex, 1)), basex = XEXP (basex, 0); | |
2023 | ||
1edcd60b | 2024 | basey = GET_CODE (rtly) == MEM ? XEXP (rtly, 0) : rtly; |
a4311dfe RK |
2025 | if (GET_CODE (basey) == PLUS && GET_CODE (XEXP (basey, 1)) == CONST_INT) |
2026 | offsety = INTVAL (XEXP (basey, 1)), basey = XEXP (basey, 0); | |
2027 | ||
d746694a | 2028 | /* If the bases are different, we know they do not overlap if both |
ca7fd9cd | 2029 | are constants or if one is a constant and the other a pointer into the |
d746694a RK |
2030 | stack frame. Otherwise a different base means we can't tell if they |
2031 | overlap or not. */ | |
2032 | if (! rtx_equal_p (basex, basey)) | |
ca7fd9cd KH |
2033 | return ((CONSTANT_P (basex) && CONSTANT_P (basey)) |
2034 | || (CONSTANT_P (basex) && REG_P (basey) | |
2035 | && REGNO_PTR_FRAME_P (REGNO (basey))) | |
2036 | || (CONSTANT_P (basey) && REG_P (basex) | |
2037 | && REGNO_PTR_FRAME_P (REGNO (basex)))); | |
a4311dfe | 2038 | |
998d7deb | 2039 | sizex = (GET_CODE (rtlx) != MEM ? (int) GET_MODE_SIZE (GET_MODE (rtlx)) |
a4311dfe RK |
2040 | : MEM_SIZE (rtlx) ? INTVAL (MEM_SIZE (rtlx)) |
2041 | : -1); | |
998d7deb | 2042 | sizey = (GET_CODE (rtly) != MEM ? (int) GET_MODE_SIZE (GET_MODE (rtly)) |
a4311dfe RK |
2043 | : MEM_SIZE (rtly) ? INTVAL (MEM_SIZE (rtly)) : |
2044 | -1); | |
2045 | ||
0af5bc3e RK |
2046 | /* If we have an offset for either memref, it can update the values computed |
2047 | above. */ | |
998d7deb RH |
2048 | if (moffsetx) |
2049 | offsetx += INTVAL (moffsetx), sizex -= INTVAL (moffsetx); | |
2050 | if (moffsety) | |
2051 | offsety += INTVAL (moffsety), sizey -= INTVAL (moffsety); | |
a4311dfe | 2052 | |
0af5bc3e | 2053 | /* If a memref has both a size and an offset, we can use the smaller size. |
efc981bb | 2054 | We can't do this if the offset isn't known because we must view this |
0af5bc3e | 2055 | memref as being anywhere inside the DECL's MEM. */ |
998d7deb | 2056 | if (MEM_SIZE (x) && moffsetx) |
a4311dfe | 2057 | sizex = INTVAL (MEM_SIZE (x)); |
998d7deb | 2058 | if (MEM_SIZE (y) && moffsety) |
a4311dfe RK |
2059 | sizey = INTVAL (MEM_SIZE (y)); |
2060 | ||
2061 | /* Put the values of the memref with the lower offset in X's values. */ | |
2062 | if (offsetx > offsety) | |
2063 | { | |
2064 | tem = offsetx, offsetx = offsety, offsety = tem; | |
2065 | tem = sizex, sizex = sizey, sizey = tem; | |
2066 | } | |
2067 | ||
2068 | /* If we don't know the size of the lower-offset value, we can't tell | |
2069 | if they conflict. Otherwise, we do the test. */ | |
a6f7c915 | 2070 | return sizex >= 0 && offsety >= offsetx + sizex; |
a4311dfe RK |
2071 | } |
2072 | ||
9ae8ffe7 JL |
2073 | /* True dependence: X is read after store in MEM takes place. */ |
2074 | ||
2075 | int | |
4682ae04 AJ |
2076 | true_dependence (rtx mem, enum machine_mode mem_mode, rtx x, |
2077 | int (*varies) (rtx, int)) | |
9ae8ffe7 | 2078 | { |
b3694847 | 2079 | rtx x_addr, mem_addr; |
49982682 | 2080 | rtx base; |
9ae8ffe7 JL |
2081 | |
2082 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) | |
2083 | return 1; | |
2084 | ||
c4484b8f RH |
2085 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
2086 | This is used in epilogue deallocation functions. */ | |
2087 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) | |
2088 | return 1; | |
2089 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
2090 | return 1; | |
2091 | ||
41472af8 MM |
2092 | if (DIFFERENT_ALIAS_SETS_P (x, mem)) |
2093 | return 0; | |
2094 | ||
b949ea8b JW |
2095 | /* Unchanging memory can't conflict with non-unchanging memory. |
2096 | A non-unchanging read can conflict with a non-unchanging write. | |
2097 | An unchanging read can conflict with an unchanging write since | |
2098 | there may be a single store to this address to initialize it. | |
ec569656 RK |
2099 | Note that an unchanging store can conflict with a non-unchanging read |
2100 | since we have to make conservative assumptions when we have a | |
2101 | record with readonly fields and we are copying the whole thing. | |
b949ea8b JW |
2102 | Just fall through to the code below to resolve potential conflicts. |
2103 | This won't handle all cases optimally, but the possible performance | |
2104 | loss should be negligible. */ | |
ec569656 | 2105 | if (RTX_UNCHANGING_P (x) && ! RTX_UNCHANGING_P (mem)) |
9ae8ffe7 JL |
2106 | return 0; |
2107 | ||
a4311dfe RK |
2108 | if (nonoverlapping_memrefs_p (mem, x)) |
2109 | return 0; | |
2110 | ||
56ee9281 RH |
2111 | if (mem_mode == VOIDmode) |
2112 | mem_mode = GET_MODE (mem); | |
2113 | ||
eab5c70a BS |
2114 | x_addr = get_addr (XEXP (x, 0)); |
2115 | mem_addr = get_addr (XEXP (mem, 0)); | |
2116 | ||
55efb413 JW |
2117 | base = find_base_term (x_addr); |
2118 | if (base && (GET_CODE (base) == LABEL_REF | |
2119 | || (GET_CODE (base) == SYMBOL_REF | |
2120 | && CONSTANT_POOL_ADDRESS_P (base)))) | |
2121 | return 0; | |
2122 | ||
eab5c70a | 2123 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), mem_mode)) |
1c72c7f6 JC |
2124 | return 0; |
2125 | ||
eab5c70a BS |
2126 | x_addr = canon_rtx (x_addr); |
2127 | mem_addr = canon_rtx (mem_addr); | |
6e73e666 | 2128 | |
0211b6ab JW |
2129 | if (! memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr, |
2130 | SIZE_FOR_MODE (x), x_addr, 0)) | |
2131 | return 0; | |
2132 | ||
c6df88cb | 2133 | if (aliases_everything_p (x)) |
0211b6ab JW |
2134 | return 1; |
2135 | ||
f5143c46 | 2136 | /* We cannot use aliases_everything_p to test MEM, since we must look |
c6df88cb MM |
2137 | at MEM_MODE, rather than GET_MODE (MEM). */ |
2138 | if (mem_mode == QImode || GET_CODE (mem_addr) == AND) | |
a13d4ebf AM |
2139 | return 1; |
2140 | ||
2141 | /* In true_dependence we also allow BLKmode to alias anything. Why | |
2142 | don't we do this in anti_dependence and output_dependence? */ | |
2143 | if (mem_mode == BLKmode || GET_MODE (x) == BLKmode) | |
2144 | return 1; | |
2145 | ||
2146 | return ! fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, | |
2147 | varies); | |
2148 | } | |
2149 | ||
2150 | /* Canonical true dependence: X is read after store in MEM takes place. | |
ca7fd9cd KH |
2151 | Variant of true_dependence which assumes MEM has already been |
2152 | canonicalized (hence we no longer do that here). | |
2153 | The mem_addr argument has been added, since true_dependence computed | |
a13d4ebf AM |
2154 | this value prior to canonicalizing. */ |
2155 | ||
2156 | int | |
4682ae04 AJ |
2157 | canon_true_dependence (rtx mem, enum machine_mode mem_mode, rtx mem_addr, |
2158 | rtx x, int (*varies) (rtx, int)) | |
a13d4ebf | 2159 | { |
b3694847 | 2160 | rtx x_addr; |
a13d4ebf AM |
2161 | |
2162 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) | |
2163 | return 1; | |
2164 | ||
0fe854a7 RH |
2165 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
2166 | This is used in epilogue deallocation functions. */ | |
2167 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) | |
2168 | return 1; | |
2169 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
2170 | return 1; | |
2171 | ||
a13d4ebf AM |
2172 | if (DIFFERENT_ALIAS_SETS_P (x, mem)) |
2173 | return 0; | |
2174 | ||
2175 | /* If X is an unchanging read, then it can't possibly conflict with any | |
2176 | non-unchanging store. It may conflict with an unchanging write though, | |
2177 | because there may be a single store to this address to initialize it. | |
2178 | Just fall through to the code below to resolve the case where we have | |
2179 | both an unchanging read and an unchanging write. This won't handle all | |
2180 | cases optimally, but the possible performance loss should be | |
2181 | negligible. */ | |
2182 | if (RTX_UNCHANGING_P (x) && ! RTX_UNCHANGING_P (mem)) | |
2183 | return 0; | |
2184 | ||
a4311dfe RK |
2185 | if (nonoverlapping_memrefs_p (x, mem)) |
2186 | return 0; | |
2187 | ||
a13d4ebf AM |
2188 | x_addr = get_addr (XEXP (x, 0)); |
2189 | ||
2190 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), mem_mode)) | |
2191 | return 0; | |
2192 | ||
2193 | x_addr = canon_rtx (x_addr); | |
2194 | if (! memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr, | |
2195 | SIZE_FOR_MODE (x), x_addr, 0)) | |
2196 | return 0; | |
2197 | ||
2198 | if (aliases_everything_p (x)) | |
2199 | return 1; | |
2200 | ||
f5143c46 | 2201 | /* We cannot use aliases_everything_p to test MEM, since we must look |
a13d4ebf AM |
2202 | at MEM_MODE, rather than GET_MODE (MEM). */ |
2203 | if (mem_mode == QImode || GET_CODE (mem_addr) == AND) | |
c6df88cb | 2204 | return 1; |
0211b6ab | 2205 | |
c6df88cb MM |
2206 | /* In true_dependence we also allow BLKmode to alias anything. Why |
2207 | don't we do this in anti_dependence and output_dependence? */ | |
2208 | if (mem_mode == BLKmode || GET_MODE (x) == BLKmode) | |
2209 | return 1; | |
0211b6ab | 2210 | |
eab5c70a BS |
2211 | return ! fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, |
2212 | varies); | |
9ae8ffe7 JL |
2213 | } |
2214 | ||
da7d8304 | 2215 | /* Returns nonzero if a write to X might alias a previous read from |
83a00410 | 2216 | (or, if WRITEP is nonzero, a write to) MEM. If CONSTP is nonzero, |
d2399d75 | 2217 | honor the RTX_UNCHANGING_P flags on X and MEM. */ |
9ae8ffe7 | 2218 | |
2c72b78f | 2219 | static int |
d2399d75 | 2220 | write_dependence_p (rtx mem, rtx x, int writep, int constp) |
9ae8ffe7 | 2221 | { |
6e73e666 | 2222 | rtx x_addr, mem_addr; |
c6df88cb | 2223 | rtx fixed_scalar; |
49982682 | 2224 | rtx base; |
6e73e666 | 2225 | |
9ae8ffe7 JL |
2226 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) |
2227 | return 1; | |
2228 | ||
c4484b8f RH |
2229 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
2230 | This is used in epilogue deallocation functions. */ | |
2231 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) | |
2232 | return 1; | |
2233 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
2234 | return 1; | |
2235 | ||
eab5c70a BS |
2236 | if (DIFFERENT_ALIAS_SETS_P (x, mem)) |
2237 | return 0; | |
2238 | ||
d2399d75 RS |
2239 | if (constp) |
2240 | { | |
2241 | /* Unchanging memory can't conflict with non-unchanging memory. */ | |
2242 | if (RTX_UNCHANGING_P (x) != RTX_UNCHANGING_P (mem)) | |
2243 | return 0; | |
b949ea8b | 2244 | |
d2399d75 RS |
2245 | /* If MEM is an unchanging read, then it can't possibly conflict with |
2246 | the store to X, because there is at most one store to MEM, and it | |
2247 | must have occurred somewhere before MEM. */ | |
2248 | if (! writep && RTX_UNCHANGING_P (mem)) | |
2249 | return 0; | |
2250 | } | |
55efb413 | 2251 | |
a4311dfe RK |
2252 | if (nonoverlapping_memrefs_p (x, mem)) |
2253 | return 0; | |
2254 | ||
55efb413 JW |
2255 | x_addr = get_addr (XEXP (x, 0)); |
2256 | mem_addr = get_addr (XEXP (mem, 0)); | |
2257 | ||
49982682 JW |
2258 | if (! writep) |
2259 | { | |
55efb413 | 2260 | base = find_base_term (mem_addr); |
49982682 JW |
2261 | if (base && (GET_CODE (base) == LABEL_REF |
2262 | || (GET_CODE (base) == SYMBOL_REF | |
2263 | && CONSTANT_POOL_ADDRESS_P (base)))) | |
2264 | return 0; | |
2265 | } | |
2266 | ||
eab5c70a BS |
2267 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), |
2268 | GET_MODE (mem))) | |
41472af8 MM |
2269 | return 0; |
2270 | ||
eab5c70a BS |
2271 | x_addr = canon_rtx (x_addr); |
2272 | mem_addr = canon_rtx (mem_addr); | |
6e73e666 | 2273 | |
c6df88cb MM |
2274 | if (!memrefs_conflict_p (SIZE_FOR_MODE (mem), mem_addr, |
2275 | SIZE_FOR_MODE (x), x_addr, 0)) | |
2276 | return 0; | |
2277 | ||
ca7fd9cd | 2278 | fixed_scalar |
eab5c70a BS |
2279 | = fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, |
2280 | rtx_addr_varies_p); | |
2281 | ||
c6df88cb MM |
2282 | return (!(fixed_scalar == mem && !aliases_everything_p (x)) |
2283 | && !(fixed_scalar == x && !aliases_everything_p (mem))); | |
2284 | } | |
2285 | ||
2286 | /* Anti dependence: X is written after read in MEM takes place. */ | |
2287 | ||
2288 | int | |
4682ae04 | 2289 | anti_dependence (rtx mem, rtx x) |
c6df88cb | 2290 | { |
d2399d75 | 2291 | return write_dependence_p (mem, x, /*writep=*/0, /*constp*/1); |
9ae8ffe7 JL |
2292 | } |
2293 | ||
2294 | /* Output dependence: X is written after store in MEM takes place. */ | |
2295 | ||
2296 | int | |
4682ae04 | 2297 | output_dependence (rtx mem, rtx x) |
9ae8ffe7 | 2298 | { |
d2399d75 RS |
2299 | return write_dependence_p (mem, x, /*writep=*/1, /*constp*/1); |
2300 | } | |
2301 | ||
2302 | /* Unchanging anti dependence: Like anti_dependence but ignores | |
2303 | the UNCHANGING_RTX_P property on const variable references. */ | |
2304 | ||
2305 | int | |
2306 | unchanging_anti_dependence (rtx mem, rtx x) | |
2307 | { | |
2308 | return write_dependence_p (mem, x, /*writep=*/0, /*constp*/0); | |
9ae8ffe7 | 2309 | } |
c14b9960 JW |
2310 | \f |
2311 | /* A subroutine of nonlocal_mentioned_p, returns 1 if *LOC mentions | |
2312 | something which is not local to the function and is not constant. */ | |
7790df19 JW |
2313 | |
2314 | static int | |
4682ae04 | 2315 | nonlocal_mentioned_p_1 (rtx *loc, void *data ATTRIBUTE_UNUSED) |
7790df19 | 2316 | { |
c14b9960 | 2317 | rtx x = *loc; |
7790df19 | 2318 | rtx base; |
7790df19 JW |
2319 | int regno; |
2320 | ||
c14b9960 JW |
2321 | if (! x) |
2322 | return 0; | |
7790df19 | 2323 | |
c14b9960 | 2324 | switch (GET_CODE (x)) |
7790df19 JW |
2325 | { |
2326 | case SUBREG: | |
2327 | if (GET_CODE (SUBREG_REG (x)) == REG) | |
2328 | { | |
2329 | /* Global registers are not local. */ | |
2330 | if (REGNO (SUBREG_REG (x)) < FIRST_PSEUDO_REGISTER | |
ddef6bc7 | 2331 | && global_regs[subreg_regno (x)]) |
7790df19 JW |
2332 | return 1; |
2333 | return 0; | |
2334 | } | |
2335 | break; | |
2336 | ||
2337 | case REG: | |
2338 | regno = REGNO (x); | |
2339 | /* Global registers are not local. */ | |
2340 | if (regno < FIRST_PSEUDO_REGISTER && global_regs[regno]) | |
2341 | return 1; | |
2342 | return 0; | |
2343 | ||
2344 | case SCRATCH: | |
2345 | case PC: | |
2346 | case CC0: | |
2347 | case CONST_INT: | |
2348 | case CONST_DOUBLE: | |
69ef87e2 | 2349 | case CONST_VECTOR: |
7790df19 JW |
2350 | case CONST: |
2351 | case LABEL_REF: | |
2352 | return 0; | |
2353 | ||
2354 | case SYMBOL_REF: | |
2355 | /* Constants in the function's constants pool are constant. */ | |
2356 | if (CONSTANT_POOL_ADDRESS_P (x)) | |
2357 | return 0; | |
2358 | return 1; | |
2359 | ||
2360 | case CALL: | |
bf6d9fd7 | 2361 | /* Non-constant calls and recursion are not local. */ |
7790df19 JW |
2362 | return 1; |
2363 | ||
2364 | case MEM: | |
2365 | /* Be overly conservative and consider any volatile memory | |
2366 | reference as not local. */ | |
2367 | if (MEM_VOLATILE_P (x)) | |
2368 | return 1; | |
2369 | base = find_base_term (XEXP (x, 0)); | |
2370 | if (base) | |
2371 | { | |
b3b5ad95 JL |
2372 | /* A Pmode ADDRESS could be a reference via the structure value |
2373 | address or static chain. Such memory references are nonlocal. | |
2374 | ||
2375 | Thus, we have to examine the contents of the ADDRESS to find | |
2376 | out if this is a local reference or not. */ | |
2377 | if (GET_CODE (base) == ADDRESS | |
2378 | && GET_MODE (base) == Pmode | |
2379 | && (XEXP (base, 0) == stack_pointer_rtx | |
2380 | || XEXP (base, 0) == arg_pointer_rtx | |
2381 | #if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM | |
2382 | || XEXP (base, 0) == hard_frame_pointer_rtx | |
2383 | #endif | |
2384 | || XEXP (base, 0) == frame_pointer_rtx)) | |
7790df19 JW |
2385 | return 0; |
2386 | /* Constants in the function's constant pool are constant. */ | |
2387 | if (GET_CODE (base) == SYMBOL_REF && CONSTANT_POOL_ADDRESS_P (base)) | |
2388 | return 0; | |
2389 | } | |
2390 | return 1; | |
2391 | ||
bf6d9fd7 | 2392 | case UNSPEC_VOLATILE: |
7790df19 | 2393 | case ASM_INPUT: |
7790df19 JW |
2394 | return 1; |
2395 | ||
bf6d9fd7 JW |
2396 | case ASM_OPERANDS: |
2397 | if (MEM_VOLATILE_P (x)) | |
2398 | return 1; | |
2399 | ||
5d3cc252 | 2400 | /* Fall through. */ |
bf6d9fd7 | 2401 | |
7790df19 JW |
2402 | default: |
2403 | break; | |
2404 | } | |
2405 | ||
c14b9960 JW |
2406 | return 0; |
2407 | } | |
2408 | ||
da7d8304 | 2409 | /* Returns nonzero if X might mention something which is not |
c14b9960 | 2410 | local to the function and is not constant. */ |
7790df19 | 2411 | |
c14b9960 | 2412 | static int |
4682ae04 | 2413 | nonlocal_mentioned_p (rtx x) |
c14b9960 | 2414 | { |
c14b9960 JW |
2415 | if (INSN_P (x)) |
2416 | { | |
2417 | if (GET_CODE (x) == CALL_INSN) | |
2418 | { | |
2419 | if (! CONST_OR_PURE_CALL_P (x)) | |
2420 | return 1; | |
2421 | x = CALL_INSN_FUNCTION_USAGE (x); | |
2422 | if (x == 0) | |
2423 | return 0; | |
ca7fd9cd | 2424 | } |
c14b9960 | 2425 | else |
ca7fd9cd | 2426 | x = PATTERN (x); |
c14b9960 JW |
2427 | } |
2428 | ||
2429 | return for_each_rtx (&x, nonlocal_mentioned_p_1, NULL); | |
2430 | } | |
2431 | ||
2432 | /* A subroutine of nonlocal_referenced_p, returns 1 if *LOC references | |
2433 | something which is not local to the function and is not constant. */ | |
2434 | ||
2435 | static int | |
4682ae04 | 2436 | nonlocal_referenced_p_1 (rtx *loc, void *data ATTRIBUTE_UNUSED) |
c14b9960 JW |
2437 | { |
2438 | rtx x = *loc; | |
2439 | ||
2440 | if (! x) | |
2441 | return 0; | |
2442 | ||
2443 | switch (GET_CODE (x)) | |
2444 | { | |
2445 | case MEM: | |
2446 | case REG: | |
2447 | case SYMBOL_REF: | |
2448 | case SUBREG: | |
2449 | return nonlocal_mentioned_p (x); | |
2450 | ||
2451 | case CALL: | |
2452 | /* Non-constant calls and recursion are not local. */ | |
2453 | return 1; | |
2454 | ||
2455 | case SET: | |
2456 | if (nonlocal_mentioned_p (SET_SRC (x))) | |
2457 | return 1; | |
2458 | ||
2459 | if (GET_CODE (SET_DEST (x)) == MEM) | |
2460 | return nonlocal_mentioned_p (XEXP (SET_DEST (x), 0)); | |
2461 | ||
2462 | /* If the destination is anything other than a CC0, PC, | |
2463 | MEM, REG, or a SUBREG of a REG that occupies all of | |
2464 | the REG, then X references nonlocal memory if it is | |
2465 | mentioned in the destination. */ | |
2466 | if (GET_CODE (SET_DEST (x)) != CC0 | |
2467 | && GET_CODE (SET_DEST (x)) != PC | |
2468 | && GET_CODE (SET_DEST (x)) != REG | |
2469 | && ! (GET_CODE (SET_DEST (x)) == SUBREG | |
2470 | && GET_CODE (SUBREG_REG (SET_DEST (x))) == REG | |
2471 | && (((GET_MODE_SIZE (GET_MODE (SUBREG_REG (SET_DEST (x)))) | |
2472 | + (UNITS_PER_WORD - 1)) / UNITS_PER_WORD) | |
2473 | == ((GET_MODE_SIZE (GET_MODE (SET_DEST (x))) | |
2474 | + (UNITS_PER_WORD - 1)) / UNITS_PER_WORD)))) | |
2475 | return nonlocal_mentioned_p (SET_DEST (x)); | |
2476 | return 0; | |
2477 | ||
2478 | case CLOBBER: | |
2479 | if (GET_CODE (XEXP (x, 0)) == MEM) | |
2480 | return nonlocal_mentioned_p (XEXP (XEXP (x, 0), 0)); | |
2481 | return 0; | |
2482 | ||
2483 | case USE: | |
2484 | return nonlocal_mentioned_p (XEXP (x, 0)); | |
2485 | ||
2486 | case ASM_INPUT: | |
2487 | case UNSPEC_VOLATILE: | |
2488 | return 1; | |
2489 | ||
2490 | case ASM_OPERANDS: | |
2491 | if (MEM_VOLATILE_P (x)) | |
2492 | return 1; | |
2493 | ||
5d3cc252 | 2494 | /* Fall through. */ |
c14b9960 JW |
2495 | |
2496 | default: | |
2497 | break; | |
2498 | } | |
2499 | ||
2500 | return 0; | |
2501 | } | |
2502 | ||
da7d8304 | 2503 | /* Returns nonzero if X might reference something which is not |
c14b9960 JW |
2504 | local to the function and is not constant. */ |
2505 | ||
2506 | static int | |
4682ae04 | 2507 | nonlocal_referenced_p (rtx x) |
c14b9960 | 2508 | { |
c14b9960 JW |
2509 | if (INSN_P (x)) |
2510 | { | |
2511 | if (GET_CODE (x) == CALL_INSN) | |
2512 | { | |
2513 | if (! CONST_OR_PURE_CALL_P (x)) | |
2514 | return 1; | |
2515 | x = CALL_INSN_FUNCTION_USAGE (x); | |
2516 | if (x == 0) | |
2517 | return 0; | |
ca7fd9cd | 2518 | } |
c14b9960 | 2519 | else |
ca7fd9cd | 2520 | x = PATTERN (x); |
c14b9960 JW |
2521 | } |
2522 | ||
2523 | return for_each_rtx (&x, nonlocal_referenced_p_1, NULL); | |
2524 | } | |
2525 | ||
2526 | /* A subroutine of nonlocal_set_p, returns 1 if *LOC sets | |
2527 | something which is not local to the function and is not constant. */ | |
2528 | ||
2529 | static int | |
4682ae04 | 2530 | nonlocal_set_p_1 (rtx *loc, void *data ATTRIBUTE_UNUSED) |
c14b9960 JW |
2531 | { |
2532 | rtx x = *loc; | |
2533 | ||
2534 | if (! x) | |
2535 | return 0; | |
2536 | ||
2537 | switch (GET_CODE (x)) | |
2538 | { | |
2539 | case CALL: | |
2540 | /* Non-constant calls and recursion are not local. */ | |
2541 | return 1; | |
2542 | ||
2543 | case PRE_INC: | |
2544 | case PRE_DEC: | |
2545 | case POST_INC: | |
2546 | case POST_DEC: | |
2547 | case PRE_MODIFY: | |
2548 | case POST_MODIFY: | |
2549 | return nonlocal_mentioned_p (XEXP (x, 0)); | |
2550 | ||
2551 | case SET: | |
2552 | if (nonlocal_mentioned_p (SET_DEST (x))) | |
2553 | return 1; | |
2554 | return nonlocal_set_p (SET_SRC (x)); | |
2555 | ||
2556 | case CLOBBER: | |
2557 | return nonlocal_mentioned_p (XEXP (x, 0)); | |
2558 | ||
2559 | case USE: | |
2560 | return 0; | |
2561 | ||
2562 | case ASM_INPUT: | |
2563 | case UNSPEC_VOLATILE: | |
2564 | return 1; | |
2565 | ||
2566 | case ASM_OPERANDS: | |
2567 | if (MEM_VOLATILE_P (x)) | |
2568 | return 1; | |
2569 | ||
5d3cc252 | 2570 | /* Fall through. */ |
c14b9960 JW |
2571 | |
2572 | default: | |
2573 | break; | |
2574 | } | |
7790df19 JW |
2575 | |
2576 | return 0; | |
2577 | } | |
2578 | ||
da7d8304 | 2579 | /* Returns nonzero if X might set something which is not |
c14b9960 JW |
2580 | local to the function and is not constant. */ |
2581 | ||
2582 | static int | |
4682ae04 | 2583 | nonlocal_set_p (rtx x) |
c14b9960 | 2584 | { |
c14b9960 JW |
2585 | if (INSN_P (x)) |
2586 | { | |
2587 | if (GET_CODE (x) == CALL_INSN) | |
2588 | { | |
2589 | if (! CONST_OR_PURE_CALL_P (x)) | |
2590 | return 1; | |
2591 | x = CALL_INSN_FUNCTION_USAGE (x); | |
2592 | if (x == 0) | |
2593 | return 0; | |
ca7fd9cd | 2594 | } |
c14b9960 | 2595 | else |
ca7fd9cd | 2596 | x = PATTERN (x); |
c14b9960 JW |
2597 | } |
2598 | ||
2599 | return for_each_rtx (&x, nonlocal_set_p_1, NULL); | |
2600 | } | |
2601 | ||
c57ddcf1 | 2602 | /* Mark the function if it is pure or constant. */ |
7790df19 JW |
2603 | |
2604 | void | |
4682ae04 | 2605 | mark_constant_function (void) |
7790df19 JW |
2606 | { |
2607 | rtx insn; | |
c14b9960 | 2608 | int nonlocal_memory_referenced; |
7790df19 | 2609 | |
ab780373 | 2610 | if (TREE_READONLY (current_function_decl) |
bf6d9fd7 | 2611 | || DECL_IS_PURE (current_function_decl) |
7790df19 | 2612 | || TREE_THIS_VOLATILE (current_function_decl) |
ab780373 RH |
2613 | || current_function_has_nonlocal_goto |
2614 | || !(*targetm.binds_local_p) (current_function_decl)) | |
7790df19 JW |
2615 | return; |
2616 | ||
e004f2f7 | 2617 | /* A loop might not return which counts as a side effect. */ |
0ecf09f9 | 2618 | if (mark_dfs_back_edges ()) |
e004f2f7 JW |
2619 | return; |
2620 | ||
c14b9960 | 2621 | nonlocal_memory_referenced = 0; |
bf6d9fd7 JW |
2622 | |
2623 | init_alias_analysis (); | |
2624 | ||
c14b9960 | 2625 | /* Determine if this is a constant or pure function. */ |
7790df19 JW |
2626 | |
2627 | for (insn = get_insns (); insn; insn = NEXT_INSN (insn)) | |
c14b9960 JW |
2628 | { |
2629 | if (! INSN_P (insn)) | |
2630 | continue; | |
bf6d9fd7 | 2631 | |
c14b9960 JW |
2632 | if (nonlocal_set_p (insn) || global_reg_mentioned_p (insn) |
2633 | || volatile_refs_p (PATTERN (insn))) | |
ca7fd9cd | 2634 | break; |
7790df19 | 2635 | |
c14b9960 JW |
2636 | if (! nonlocal_memory_referenced) |
2637 | nonlocal_memory_referenced = nonlocal_referenced_p (insn); | |
2638 | } | |
ca7fd9cd | 2639 | |
c14b9960 | 2640 | end_alias_analysis (); |
ca7fd9cd | 2641 | |
7790df19 | 2642 | /* Mark the function. */ |
ca7fd9cd | 2643 | |
c14b9960 JW |
2644 | if (insn) |
2645 | ; | |
2646 | else if (nonlocal_memory_referenced) | |
c57ddcf1 RS |
2647 | { |
2648 | cgraph_rtl_info (current_function_decl)->pure_function = 1; | |
2649 | DECL_IS_PURE (current_function_decl) = 1; | |
2650 | } | |
c14b9960 | 2651 | else |
c57ddcf1 RS |
2652 | { |
2653 | cgraph_rtl_info (current_function_decl)->const_function = 1; | |
2654 | TREE_READONLY (current_function_decl) = 1; | |
2655 | } | |
7790df19 | 2656 | } |
c14b9960 | 2657 | \f |
6e73e666 | 2658 | |
6e73e666 | 2659 | void |
4682ae04 | 2660 | init_alias_once (void) |
6e73e666 | 2661 | { |
b3694847 | 2662 | int i; |
6e73e666 | 2663 | |
6e73e666 JC |
2664 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) |
2665 | /* Check whether this register can hold an incoming pointer | |
2666 | argument. FUNCTION_ARG_REGNO_P tests outgoing register | |
ec5c56db | 2667 | numbers, so translate if necessary due to register windows. */ |
6e73e666 JC |
2668 | if (FUNCTION_ARG_REGNO_P (OUTGOING_REGNO (i)) |
2669 | && HARD_REGNO_MODE_OK (i, Pmode)) | |
bf1660a6 JL |
2670 | static_reg_base_value[i] |
2671 | = gen_rtx_ADDRESS (VOIDmode, gen_rtx_REG (Pmode, i)); | |
2672 | ||
bf1660a6 JL |
2673 | static_reg_base_value[STACK_POINTER_REGNUM] |
2674 | = gen_rtx_ADDRESS (Pmode, stack_pointer_rtx); | |
2675 | static_reg_base_value[ARG_POINTER_REGNUM] | |
2676 | = gen_rtx_ADDRESS (Pmode, arg_pointer_rtx); | |
2677 | static_reg_base_value[FRAME_POINTER_REGNUM] | |
2678 | = gen_rtx_ADDRESS (Pmode, frame_pointer_rtx); | |
2679 | #if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM | |
2680 | static_reg_base_value[HARD_FRAME_POINTER_REGNUM] | |
2681 | = gen_rtx_ADDRESS (Pmode, hard_frame_pointer_rtx); | |
2682 | #endif | |
2683 | } | |
2684 | ||
7b52eede JH |
2685 | /* Set MEMORY_MODIFIED when X modifies DATA (that is assumed |
2686 | to be memory reference. */ | |
2687 | static bool memory_modified; | |
2688 | static void | |
4682ae04 | 2689 | memory_modified_1 (rtx x, rtx pat ATTRIBUTE_UNUSED, void *data) |
7b52eede JH |
2690 | { |
2691 | if (GET_CODE (x) == MEM) | |
2692 | { | |
2693 | if (anti_dependence (x, (rtx)data) || output_dependence (x, (rtx)data)) | |
2694 | memory_modified = true; | |
2695 | } | |
2696 | } | |
2697 | ||
2698 | ||
2699 | /* Return true when INSN possibly modify memory contents of MEM | |
2700 | (ie address can be modified). */ | |
2701 | bool | |
4682ae04 | 2702 | memory_modified_in_insn_p (rtx mem, rtx insn) |
7b52eede JH |
2703 | { |
2704 | if (!INSN_P (insn)) | |
2705 | return false; | |
2706 | memory_modified = false; | |
2707 | note_stores (PATTERN (insn), memory_modified_1, mem); | |
2708 | return memory_modified; | |
2709 | } | |
2710 | ||
c13e8210 MM |
2711 | /* Initialize the aliasing machinery. Initialize the REG_KNOWN_VALUE |
2712 | array. */ | |
2713 | ||
9ae8ffe7 | 2714 | void |
4682ae04 | 2715 | init_alias_analysis (void) |
9ae8ffe7 | 2716 | { |
c582d54a | 2717 | unsigned int maxreg = max_reg_num (); |
ea64ef27 | 2718 | int changed, pass; |
b3694847 SS |
2719 | int i; |
2720 | unsigned int ui; | |
2721 | rtx insn; | |
9ae8ffe7 | 2722 | |
0d446150 JH |
2723 | timevar_push (TV_ALIAS_ANALYSIS); |
2724 | ||
9ae8ffe7 JL |
2725 | reg_known_value_size = maxreg; |
2726 | ||
ca7fd9cd | 2727 | reg_known_value |
e05e2395 MM |
2728 | = (rtx *) xcalloc ((maxreg - FIRST_PSEUDO_REGISTER), sizeof (rtx)) |
2729 | - FIRST_PSEUDO_REGISTER; | |
ca7fd9cd | 2730 | reg_known_equiv_p |
e05e2395 | 2731 | = (char*) xcalloc ((maxreg - FIRST_PSEUDO_REGISTER), sizeof (char)) |
9ae8ffe7 | 2732 | - FIRST_PSEUDO_REGISTER; |
9ae8ffe7 | 2733 | |
6e73e666 JC |
2734 | /* Overallocate reg_base_value to allow some growth during loop |
2735 | optimization. Loop unrolling can create a large number of | |
2736 | registers. */ | |
c582d54a JH |
2737 | if (old_reg_base_value) |
2738 | { | |
2739 | reg_base_value = old_reg_base_value; | |
2740 | /* If varray gets large zeroing cost may get important. */ | |
2741 | if (VARRAY_SIZE (reg_base_value) > 256 | |
2742 | && VARRAY_SIZE (reg_base_value) > 4 * maxreg) | |
2743 | VARRAY_GROW (reg_base_value, maxreg); | |
2744 | VARRAY_CLEAR (reg_base_value); | |
2745 | if (VARRAY_SIZE (reg_base_value) < maxreg) | |
2746 | VARRAY_GROW (reg_base_value, maxreg); | |
2747 | } | |
2748 | else | |
2749 | { | |
2750 | VARRAY_RTX_INIT (reg_base_value, maxreg, "reg_base_value"); | |
2751 | } | |
ac606739 | 2752 | |
c582d54a JH |
2753 | new_reg_base_value = xmalloc (maxreg * sizeof (rtx)); |
2754 | reg_seen = xmalloc (maxreg); | |
b17d5d7c | 2755 | if (! reload_completed && flag_old_unroll_loops) |
de12be17 | 2756 | { |
ac606739 | 2757 | /* ??? Why are we realloc'ing if we're just going to zero it? */ |
703ad42b | 2758 | alias_invariant = xrealloc (alias_invariant, |
c582d54a JH |
2759 | maxreg * sizeof (rtx)); |
2760 | memset (alias_invariant, 0, maxreg * sizeof (rtx)); | |
2761 | alias_invariant_size = maxreg; | |
de12be17 | 2762 | } |
ec907dd8 JL |
2763 | |
2764 | /* The basic idea is that each pass through this loop will use the | |
2765 | "constant" information from the previous pass to propagate alias | |
2766 | information through another level of assignments. | |
2767 | ||
2768 | This could get expensive if the assignment chains are long. Maybe | |
2769 | we should throttle the number of iterations, possibly based on | |
6e73e666 | 2770 | the optimization level or flag_expensive_optimizations. |
ec907dd8 JL |
2771 | |
2772 | We could propagate more information in the first pass by making use | |
2773 | of REG_N_SETS to determine immediately that the alias information | |
ea64ef27 JL |
2774 | for a pseudo is "constant". |
2775 | ||
2776 | A program with an uninitialized variable can cause an infinite loop | |
2777 | here. Instead of doing a full dataflow analysis to detect such problems | |
2778 | we just cap the number of iterations for the loop. | |
2779 | ||
2780 | The state of the arrays for the set chain in question does not matter | |
2781 | since the program has undefined behavior. */ | |
6e73e666 | 2782 | |
ea64ef27 | 2783 | pass = 0; |
6e73e666 | 2784 | do |
ec907dd8 JL |
2785 | { |
2786 | /* Assume nothing will change this iteration of the loop. */ | |
2787 | changed = 0; | |
2788 | ||
ec907dd8 JL |
2789 | /* We want to assign the same IDs each iteration of this loop, so |
2790 | start counting from zero each iteration of the loop. */ | |
2791 | unique_id = 0; | |
2792 | ||
f5143c46 | 2793 | /* We're at the start of the function each iteration through the |
ec907dd8 | 2794 | loop, so we're copying arguments. */ |
83bbd9b6 | 2795 | copying_arguments = true; |
9ae8ffe7 | 2796 | |
6e73e666 | 2797 | /* Wipe the potential alias information clean for this pass. */ |
c582d54a | 2798 | memset (new_reg_base_value, 0, maxreg * sizeof (rtx)); |
8072f69c | 2799 | |
6e73e666 | 2800 | /* Wipe the reg_seen array clean. */ |
c582d54a | 2801 | memset (reg_seen, 0, maxreg); |
9ae8ffe7 | 2802 | |
6e73e666 JC |
2803 | /* Mark all hard registers which may contain an address. |
2804 | The stack, frame and argument pointers may contain an address. | |
2805 | An argument register which can hold a Pmode value may contain | |
2806 | an address even if it is not in BASE_REGS. | |
8072f69c | 2807 | |
6e73e666 JC |
2808 | The address expression is VOIDmode for an argument and |
2809 | Pmode for other registers. */ | |
2810 | ||
7f243674 JL |
2811 | memcpy (new_reg_base_value, static_reg_base_value, |
2812 | FIRST_PSEUDO_REGISTER * sizeof (rtx)); | |
6e73e666 | 2813 | |
ec907dd8 JL |
2814 | /* Walk the insns adding values to the new_reg_base_value array. */ |
2815 | for (insn = get_insns (); insn; insn = NEXT_INSN (insn)) | |
9ae8ffe7 | 2816 | { |
2c3c49de | 2817 | if (INSN_P (insn)) |
ec907dd8 | 2818 | { |
6e73e666 | 2819 | rtx note, set; |
efc9bd41 RK |
2820 | |
2821 | #if defined (HAVE_prologue) || defined (HAVE_epilogue) | |
f5143c46 | 2822 | /* The prologue/epilogue insns are not threaded onto the |
657959ca JL |
2823 | insn chain until after reload has completed. Thus, |
2824 | there is no sense wasting time checking if INSN is in | |
2825 | the prologue/epilogue until after reload has completed. */ | |
2826 | if (reload_completed | |
2827 | && prologue_epilogue_contains (insn)) | |
efc9bd41 RK |
2828 | continue; |
2829 | #endif | |
2830 | ||
ec907dd8 JL |
2831 | /* If this insn has a noalias note, process it, Otherwise, |
2832 | scan for sets. A simple set will have no side effects | |
ec5c56db | 2833 | which could change the base value of any other register. */ |
6e73e666 | 2834 | |
ec907dd8 | 2835 | if (GET_CODE (PATTERN (insn)) == SET |
efc9bd41 RK |
2836 | && REG_NOTES (insn) != 0 |
2837 | && find_reg_note (insn, REG_NOALIAS, NULL_RTX)) | |
84832317 | 2838 | record_set (SET_DEST (PATTERN (insn)), NULL_RTX, NULL); |
ec907dd8 | 2839 | else |
84832317 | 2840 | note_stores (PATTERN (insn), record_set, NULL); |
6e73e666 JC |
2841 | |
2842 | set = single_set (insn); | |
2843 | ||
2844 | if (set != 0 | |
2845 | && GET_CODE (SET_DEST (set)) == REG | |
fb6754f0 | 2846 | && REGNO (SET_DEST (set)) >= FIRST_PSEUDO_REGISTER) |
6e73e666 | 2847 | { |
fb6754f0 | 2848 | unsigned int regno = REGNO (SET_DEST (set)); |
713f41f9 BS |
2849 | rtx src = SET_SRC (set); |
2850 | ||
2851 | if (REG_NOTES (insn) != 0 | |
2852 | && (((note = find_reg_note (insn, REG_EQUAL, 0)) != 0 | |
2853 | && REG_N_SETS (regno) == 1) | |
2854 | || (note = find_reg_note (insn, REG_EQUIV, NULL_RTX)) != 0) | |
2855 | && GET_CODE (XEXP (note, 0)) != EXPR_LIST | |
bb2cf916 | 2856 | && ! rtx_varies_p (XEXP (note, 0), 1) |
713f41f9 BS |
2857 | && ! reg_overlap_mentioned_p (SET_DEST (set), XEXP (note, 0))) |
2858 | { | |
2859 | reg_known_value[regno] = XEXP (note, 0); | |
2860 | reg_known_equiv_p[regno] = REG_NOTE_KIND (note) == REG_EQUIV; | |
2861 | } | |
2862 | else if (REG_N_SETS (regno) == 1 | |
2863 | && GET_CODE (src) == PLUS | |
2864 | && GET_CODE (XEXP (src, 0)) == REG | |
fb6754f0 BS |
2865 | && REGNO (XEXP (src, 0)) >= FIRST_PSEUDO_REGISTER |
2866 | && (reg_known_value[REGNO (XEXP (src, 0))]) | |
713f41f9 BS |
2867 | && GET_CODE (XEXP (src, 1)) == CONST_INT) |
2868 | { | |
2869 | rtx op0 = XEXP (src, 0); | |
bb2cf916 | 2870 | op0 = reg_known_value[REGNO (op0)]; |
713f41f9 | 2871 | reg_known_value[regno] |
ed8908e7 | 2872 | = plus_constant (op0, INTVAL (XEXP (src, 1))); |
713f41f9 BS |
2873 | reg_known_equiv_p[regno] = 0; |
2874 | } | |
2875 | else if (REG_N_SETS (regno) == 1 | |
2876 | && ! rtx_varies_p (src, 1)) | |
2877 | { | |
2878 | reg_known_value[regno] = src; | |
2879 | reg_known_equiv_p[regno] = 0; | |
2880 | } | |
6e73e666 | 2881 | } |
ec907dd8 JL |
2882 | } |
2883 | else if (GET_CODE (insn) == NOTE | |
2884 | && NOTE_LINE_NUMBER (insn) == NOTE_INSN_FUNCTION_BEG) | |
83bbd9b6 | 2885 | copying_arguments = false; |
6e73e666 | 2886 | } |
ec907dd8 | 2887 | |
6e73e666 | 2888 | /* Now propagate values from new_reg_base_value to reg_base_value. */ |
c582d54a JH |
2889 | if (maxreg != (unsigned int) max_reg_num()) |
2890 | abort (); | |
2891 | for (ui = 0; ui < maxreg; ui++) | |
6e73e666 | 2892 | { |
e51712db | 2893 | if (new_reg_base_value[ui] |
c582d54a JH |
2894 | && new_reg_base_value[ui] != VARRAY_RTX (reg_base_value, ui) |
2895 | && ! rtx_equal_p (new_reg_base_value[ui], | |
2896 | VARRAY_RTX (reg_base_value, ui))) | |
ec907dd8 | 2897 | { |
c582d54a | 2898 | VARRAY_RTX (reg_base_value, ui) = new_reg_base_value[ui]; |
6e73e666 | 2899 | changed = 1; |
ec907dd8 | 2900 | } |
9ae8ffe7 | 2901 | } |
9ae8ffe7 | 2902 | } |
6e73e666 | 2903 | while (changed && ++pass < MAX_ALIAS_LOOP_PASSES); |
9ae8ffe7 JL |
2904 | |
2905 | /* Fill in the remaining entries. */ | |
c582d54a | 2906 | for (i = FIRST_PSEUDO_REGISTER; i < (int)maxreg; i++) |
9ae8ffe7 JL |
2907 | if (reg_known_value[i] == 0) |
2908 | reg_known_value[i] = regno_reg_rtx[i]; | |
2909 | ||
9ae8ffe7 JL |
2910 | /* Simplify the reg_base_value array so that no register refers to |
2911 | another register, except to special registers indirectly through | |
2912 | ADDRESS expressions. | |
2913 | ||
2914 | In theory this loop can take as long as O(registers^2), but unless | |
2915 | there are very long dependency chains it will run in close to linear | |
ea64ef27 JL |
2916 | time. |
2917 | ||
2918 | This loop may not be needed any longer now that the main loop does | |
2919 | a better job at propagating alias information. */ | |
2920 | pass = 0; | |
9ae8ffe7 JL |
2921 | do |
2922 | { | |
2923 | changed = 0; | |
ea64ef27 | 2924 | pass++; |
c582d54a | 2925 | for (ui = 0; ui < maxreg; ui++) |
9ae8ffe7 | 2926 | { |
c582d54a | 2927 | rtx base = VARRAY_RTX (reg_base_value, ui); |
9ae8ffe7 JL |
2928 | if (base && GET_CODE (base) == REG) |
2929 | { | |
fb6754f0 | 2930 | unsigned int base_regno = REGNO (base); |
e51712db | 2931 | if (base_regno == ui) /* register set from itself */ |
c582d54a | 2932 | VARRAY_RTX (reg_base_value, ui) = 0; |
9ae8ffe7 | 2933 | else |
c582d54a JH |
2934 | VARRAY_RTX (reg_base_value, ui) |
2935 | = VARRAY_RTX (reg_base_value, base_regno); | |
9ae8ffe7 JL |
2936 | changed = 1; |
2937 | } | |
2938 | } | |
2939 | } | |
ea64ef27 | 2940 | while (changed && pass < MAX_ALIAS_LOOP_PASSES); |
9ae8ffe7 | 2941 | |
e05e2395 MM |
2942 | /* Clean up. */ |
2943 | free (new_reg_base_value); | |
ec907dd8 | 2944 | new_reg_base_value = 0; |
e05e2395 | 2945 | free (reg_seen); |
9ae8ffe7 | 2946 | reg_seen = 0; |
0d446150 | 2947 | timevar_pop (TV_ALIAS_ANALYSIS); |
9ae8ffe7 JL |
2948 | } |
2949 | ||
2950 | void | |
4682ae04 | 2951 | end_alias_analysis (void) |
9ae8ffe7 | 2952 | { |
c582d54a | 2953 | old_reg_base_value = reg_base_value; |
e05e2395 | 2954 | free (reg_known_value + FIRST_PSEUDO_REGISTER); |
9ae8ffe7 | 2955 | reg_known_value = 0; |
ac606739 | 2956 | reg_known_value_size = 0; |
e05e2395 MM |
2957 | free (reg_known_equiv_p + FIRST_PSEUDO_REGISTER); |
2958 | reg_known_equiv_p = 0; | |
de12be17 JC |
2959 | if (alias_invariant) |
2960 | { | |
ac606739 | 2961 | free (alias_invariant); |
de12be17 | 2962 | alias_invariant = 0; |
c582d54a | 2963 | alias_invariant_size = 0; |
de12be17 | 2964 | } |
9ae8ffe7 | 2965 | } |
e2500fed GK |
2966 | |
2967 | #include "gt-alias.h" |