]>
Commit | Line | Data |
---|---|---|
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 | |
e2500fed | 160 | static GTY((length ("reg_base_value_size"))) rtx *reg_base_value; |
ac606739 | 161 | static rtx *new_reg_base_value; |
d4b60170 RK |
162 | static unsigned int reg_base_value_size; /* size of reg_base_value array */ |
163 | ||
bf1660a6 JL |
164 | /* Static hunks of RTL used by the aliasing code; these are initialized |
165 | once per function to avoid unnecessary RTL allocations. */ | |
166 | static GTY (()) rtx static_reg_base_value[FIRST_PSEUDO_REGISTER]; | |
167 | ||
9ae8ffe7 | 168 | #define REG_BASE_VALUE(X) \ |
fb6754f0 BS |
169 | (REGNO (X) < reg_base_value_size \ |
170 | ? reg_base_value[REGNO (X)] : 0) | |
9ae8ffe7 | 171 | |
de12be17 JC |
172 | /* Vector of known invariant relationships between registers. Set in |
173 | loop unrolling. Indexed by register number, if nonzero the value | |
174 | is an expression describing this register in terms of another. | |
175 | ||
176 | The length of this array is REG_BASE_VALUE_SIZE. | |
177 | ||
178 | Because this array contains only pseudo registers it has no effect | |
179 | after reload. */ | |
180 | static rtx *alias_invariant; | |
181 | ||
c13e8210 MM |
182 | /* Vector indexed by N giving the initial (unchanging) value known for |
183 | pseudo-register N. This array is initialized in | |
184 | init_alias_analysis, and does not change until end_alias_analysis | |
185 | is called. */ | |
9ae8ffe7 JL |
186 | rtx *reg_known_value; |
187 | ||
188 | /* Indicates number of valid entries in reg_known_value. */ | |
770ae6cc | 189 | static unsigned int reg_known_value_size; |
9ae8ffe7 JL |
190 | |
191 | /* Vector recording for each reg_known_value whether it is due to a | |
192 | REG_EQUIV note. Future passes (viz., reload) may replace the | |
193 | pseudo with the equivalent expression and so we account for the | |
ac3d9668 RK |
194 | dependences that would be introduced if that happens. |
195 | ||
196 | The REG_EQUIV notes created in assign_parms may mention the arg | |
197 | pointer, and there are explicit insns in the RTL that modify the | |
198 | arg pointer. Thus we must ensure that such insns don't get | |
199 | scheduled across each other because that would invalidate the | |
200 | REG_EQUIV notes. One could argue that the REG_EQUIV notes are | |
201 | wrong, but solving the problem in the scheduler will likely give | |
202 | better code, so we do it here. */ | |
9ae8ffe7 JL |
203 | char *reg_known_equiv_p; |
204 | ||
2a2c8203 JC |
205 | /* True when scanning insns from the start of the rtl to the |
206 | NOTE_INSN_FUNCTION_BEG note. */ | |
83bbd9b6 | 207 | static bool copying_arguments; |
9ae8ffe7 | 208 | |
3932261a | 209 | /* The splay-tree used to store the various alias set entries. */ |
b604074c | 210 | static GTY ((param_is (struct alias_set_entry))) varray_type alias_sets; |
ac3d9668 | 211 | \f |
3932261a MM |
212 | /* Returns a pointer to the alias set entry for ALIAS_SET, if there is |
213 | such an entry, or NULL otherwise. */ | |
214 | ||
9ddb66ca | 215 | static inline alias_set_entry |
4682ae04 | 216 | get_alias_set_entry (HOST_WIDE_INT alias_set) |
3932261a | 217 | { |
9ddb66ca | 218 | return (alias_set_entry)VARRAY_GENERIC_PTR (alias_sets, alias_set); |
3932261a MM |
219 | } |
220 | ||
ac3d9668 RK |
221 | /* Returns nonzero if the alias sets for MEM1 and MEM2 are such that |
222 | the two MEMs cannot alias each other. */ | |
3932261a | 223 | |
9ddb66ca | 224 | static inline int |
4682ae04 | 225 | mems_in_disjoint_alias_sets_p (rtx mem1, rtx mem2) |
3932261a | 226 | { |
ca7fd9cd | 227 | #ifdef ENABLE_CHECKING |
3932261a MM |
228 | /* Perform a basic sanity check. Namely, that there are no alias sets |
229 | if we're not using strict aliasing. This helps to catch bugs | |
230 | whereby someone uses PUT_CODE, but doesn't clear MEM_ALIAS_SET, or | |
231 | where a MEM is allocated in some way other than by the use of | |
232 | gen_rtx_MEM, and the MEM_ALIAS_SET is not cleared. If we begin to | |
233 | use alias sets to indicate that spilled registers cannot alias each | |
234 | other, we might need to remove this check. */ | |
d4b60170 RK |
235 | if (! flag_strict_aliasing |
236 | && (MEM_ALIAS_SET (mem1) != 0 || MEM_ALIAS_SET (mem2) != 0)) | |
3932261a MM |
237 | abort (); |
238 | #endif | |
239 | ||
1da68f56 RK |
240 | return ! alias_sets_conflict_p (MEM_ALIAS_SET (mem1), MEM_ALIAS_SET (mem2)); |
241 | } | |
3932261a | 242 | |
1da68f56 RK |
243 | /* Insert the NODE into the splay tree given by DATA. Used by |
244 | record_alias_subset via splay_tree_foreach. */ | |
245 | ||
246 | static int | |
4682ae04 | 247 | insert_subset_children (splay_tree_node node, void *data) |
1da68f56 RK |
248 | { |
249 | splay_tree_insert ((splay_tree) data, node->key, node->value); | |
250 | ||
251 | return 0; | |
252 | } | |
253 | ||
254 | /* Return 1 if the two specified alias sets may conflict. */ | |
255 | ||
256 | int | |
4682ae04 | 257 | alias_sets_conflict_p (HOST_WIDE_INT set1, HOST_WIDE_INT set2) |
1da68f56 RK |
258 | { |
259 | alias_set_entry ase; | |
260 | ||
261 | /* If have no alias set information for one of the operands, we have | |
262 | to assume it can alias anything. */ | |
263 | if (set1 == 0 || set2 == 0 | |
264 | /* If the two alias sets are the same, they may alias. */ | |
265 | || set1 == set2) | |
266 | return 1; | |
3932261a | 267 | |
3bdf5ad1 | 268 | /* See if the first alias set is a subset of the second. */ |
1da68f56 | 269 | ase = get_alias_set_entry (set1); |
2bf105ab RK |
270 | if (ase != 0 |
271 | && (ase->has_zero_child | |
272 | || splay_tree_lookup (ase->children, | |
1da68f56 RK |
273 | (splay_tree_key) set2))) |
274 | return 1; | |
3932261a MM |
275 | |
276 | /* Now do the same, but with the alias sets reversed. */ | |
1da68f56 | 277 | ase = get_alias_set_entry (set2); |
2bf105ab RK |
278 | if (ase != 0 |
279 | && (ase->has_zero_child | |
280 | || splay_tree_lookup (ase->children, | |
1da68f56 RK |
281 | (splay_tree_key) set1))) |
282 | return 1; | |
3932261a | 283 | |
1da68f56 | 284 | /* The two alias sets are distinct and neither one is the |
3932261a | 285 | child of the other. Therefore, they cannot alias. */ |
1da68f56 | 286 | return 0; |
3932261a | 287 | } |
1da68f56 RK |
288 | \f |
289 | /* Return 1 if TYPE is a RECORD_TYPE, UNION_TYPE, or QUAL_UNION_TYPE and has | |
290 | has any readonly fields. If any of the fields have types that | |
291 | contain readonly fields, return true as well. */ | |
3932261a | 292 | |
1da68f56 | 293 | int |
4682ae04 | 294 | readonly_fields_p (tree type) |
3932261a | 295 | { |
1da68f56 RK |
296 | tree field; |
297 | ||
298 | if (TREE_CODE (type) != RECORD_TYPE && TREE_CODE (type) != UNION_TYPE | |
299 | && TREE_CODE (type) != QUAL_UNION_TYPE) | |
300 | return 0; | |
301 | ||
302 | for (field = TYPE_FIELDS (type); field != 0; field = TREE_CHAIN (field)) | |
303 | if (TREE_CODE (field) == FIELD_DECL | |
304 | && (TREE_READONLY (field) | |
305 | || readonly_fields_p (TREE_TYPE (field)))) | |
306 | return 1; | |
3932261a MM |
307 | |
308 | return 0; | |
309 | } | |
3bdf5ad1 | 310 | \f |
1da68f56 RK |
311 | /* Return 1 if any MEM object of type T1 will always conflict (using the |
312 | dependency routines in this file) with any MEM object of type T2. | |
313 | This is used when allocating temporary storage. If T1 and/or T2 are | |
314 | NULL_TREE, it means we know nothing about the storage. */ | |
315 | ||
316 | int | |
4682ae04 | 317 | objects_must_conflict_p (tree t1, tree t2) |
1da68f56 | 318 | { |
82d610ec RK |
319 | HOST_WIDE_INT set1, set2; |
320 | ||
e8ea2809 RK |
321 | /* If neither has a type specified, we don't know if they'll conflict |
322 | because we may be using them to store objects of various types, for | |
323 | example the argument and local variables areas of inlined functions. */ | |
981a4c34 | 324 | if (t1 == 0 && t2 == 0) |
e8ea2809 RK |
325 | return 0; |
326 | ||
66cce54d RH |
327 | /* If one or the other has readonly fields or is readonly, |
328 | then they may not conflict. */ | |
329 | if ((t1 != 0 && readonly_fields_p (t1)) | |
330 | || (t2 != 0 && readonly_fields_p (t2)) | |
a3b88570 MM |
331 | || (t1 != 0 && lang_hooks.honor_readonly && TYPE_READONLY (t1)) |
332 | || (t2 != 0 && lang_hooks.honor_readonly && TYPE_READONLY (t2))) | |
66cce54d RH |
333 | return 0; |
334 | ||
1da68f56 RK |
335 | /* If they are the same type, they must conflict. */ |
336 | if (t1 == t2 | |
337 | /* Likewise if both are volatile. */ | |
338 | || (t1 != 0 && TYPE_VOLATILE (t1) && t2 != 0 && TYPE_VOLATILE (t2))) | |
339 | return 1; | |
340 | ||
82d610ec RK |
341 | set1 = t1 ? get_alias_set (t1) : 0; |
342 | set2 = t2 ? get_alias_set (t2) : 0; | |
1da68f56 | 343 | |
82d610ec RK |
344 | /* Otherwise they conflict if they have no alias set or the same. We |
345 | can't simply use alias_sets_conflict_p here, because we must make | |
346 | sure that every subtype of t1 will conflict with every subtype of | |
347 | t2 for which a pair of subobjects of these respective subtypes | |
348 | overlaps on the stack. */ | |
349 | return set1 == 0 || set2 == 0 || set1 == set2; | |
1da68f56 RK |
350 | } |
351 | \f | |
3bdf5ad1 RK |
352 | /* T is an expression with pointer type. Find the DECL on which this |
353 | expression is based. (For example, in `a[i]' this would be `a'.) | |
354 | If there is no such DECL, or a unique decl cannot be determined, | |
f5143c46 | 355 | NULL_TREE is returned. */ |
3bdf5ad1 RK |
356 | |
357 | static tree | |
4682ae04 | 358 | find_base_decl (tree t) |
3bdf5ad1 RK |
359 | { |
360 | tree d0, d1, d2; | |
361 | ||
362 | if (t == 0 || t == error_mark_node || ! POINTER_TYPE_P (TREE_TYPE (t))) | |
363 | return 0; | |
364 | ||
365 | /* If this is a declaration, return it. */ | |
366 | if (TREE_CODE_CLASS (TREE_CODE (t)) == 'd') | |
367 | return t; | |
368 | ||
369 | /* Handle general expressions. It would be nice to deal with | |
370 | COMPONENT_REFs here. If we could tell that `a' and `b' were the | |
371 | same, then `a->f' and `b->f' are also the same. */ | |
372 | switch (TREE_CODE_CLASS (TREE_CODE (t))) | |
373 | { | |
374 | case '1': | |
375 | return find_base_decl (TREE_OPERAND (t, 0)); | |
376 | ||
377 | case '2': | |
378 | /* Return 0 if found in neither or both are the same. */ | |
379 | d0 = find_base_decl (TREE_OPERAND (t, 0)); | |
380 | d1 = find_base_decl (TREE_OPERAND (t, 1)); | |
381 | if (d0 == d1) | |
382 | return d0; | |
383 | else if (d0 == 0) | |
384 | return d1; | |
385 | else if (d1 == 0) | |
386 | return d0; | |
387 | else | |
388 | return 0; | |
389 | ||
390 | case '3': | |
391 | d0 = find_base_decl (TREE_OPERAND (t, 0)); | |
392 | d1 = find_base_decl (TREE_OPERAND (t, 1)); | |
3bdf5ad1 RK |
393 | d2 = find_base_decl (TREE_OPERAND (t, 2)); |
394 | ||
395 | /* Set any nonzero values from the last, then from the first. */ | |
396 | if (d1 == 0) d1 = d2; | |
397 | if (d0 == 0) d0 = d1; | |
398 | if (d1 == 0) d1 = d0; | |
399 | if (d2 == 0) d2 = d1; | |
400 | ||
401 | /* At this point all are nonzero or all are zero. If all three are the | |
402 | same, return it. Otherwise, return zero. */ | |
403 | return (d0 == d1 && d1 == d2) ? d0 : 0; | |
404 | ||
405 | default: | |
406 | return 0; | |
407 | } | |
408 | } | |
409 | ||
6e24b709 RK |
410 | /* Return 1 if all the nested component references handled by |
411 | get_inner_reference in T are such that we can address the object in T. */ | |
412 | ||
10b76d73 | 413 | int |
4682ae04 | 414 | can_address_p (tree t) |
6e24b709 RK |
415 | { |
416 | /* If we're at the end, it is vacuously addressable. */ | |
417 | if (! handled_component_p (t)) | |
418 | return 1; | |
419 | ||
420 | /* Bitfields are never addressable. */ | |
421 | else if (TREE_CODE (t) == BIT_FIELD_REF) | |
422 | return 0; | |
423 | ||
8ac61af7 RK |
424 | /* Fields are addressable unless they are marked as nonaddressable or |
425 | the containing type has alias set 0. */ | |
6e24b709 RK |
426 | else if (TREE_CODE (t) == COMPONENT_REF |
427 | && ! DECL_NONADDRESSABLE_P (TREE_OPERAND (t, 1)) | |
8ac61af7 | 428 | && get_alias_set (TREE_TYPE (TREE_OPERAND (t, 0))) != 0 |
6e24b709 RK |
429 | && can_address_p (TREE_OPERAND (t, 0))) |
430 | return 1; | |
431 | ||
8ac61af7 | 432 | /* Likewise for arrays. */ |
b4e3fabb | 433 | else if ((TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF) |
6e24b709 | 434 | && ! TYPE_NONALIASED_COMPONENT (TREE_TYPE (TREE_OPERAND (t, 0))) |
8ac61af7 | 435 | && get_alias_set (TREE_TYPE (TREE_OPERAND (t, 0))) != 0 |
6e24b709 RK |
436 | && can_address_p (TREE_OPERAND (t, 0))) |
437 | return 1; | |
438 | ||
439 | return 0; | |
440 | } | |
441 | ||
3bdf5ad1 RK |
442 | /* Return the alias set for T, which may be either a type or an |
443 | expression. Call language-specific routine for help, if needed. */ | |
444 | ||
445 | HOST_WIDE_INT | |
4682ae04 | 446 | get_alias_set (tree t) |
3bdf5ad1 RK |
447 | { |
448 | HOST_WIDE_INT set; | |
3bdf5ad1 RK |
449 | |
450 | /* If we're not doing any alias analysis, just assume everything | |
451 | aliases everything else. Also return 0 if this or its type is | |
452 | an error. */ | |
453 | if (! flag_strict_aliasing || t == error_mark_node | |
454 | || (! TYPE_P (t) | |
455 | && (TREE_TYPE (t) == 0 || TREE_TYPE (t) == error_mark_node))) | |
456 | return 0; | |
457 | ||
458 | /* We can be passed either an expression or a type. This and the | |
f47e9b4e RK |
459 | language-specific routine may make mutually-recursive calls to each other |
460 | to figure out what to do. At each juncture, we see if this is a tree | |
461 | that the language may need to handle specially. First handle things that | |
738cc472 | 462 | aren't types. */ |
f824e5c3 | 463 | if (! TYPE_P (t)) |
3bdf5ad1 | 464 | { |
738cc472 RK |
465 | tree inner = t; |
466 | tree placeholder_ptr = 0; | |
467 | ||
8ac61af7 RK |
468 | /* Remove any nops, then give the language a chance to do |
469 | something with this tree before we look at it. */ | |
470 | STRIP_NOPS (t); | |
471 | set = (*lang_hooks.get_alias_set) (t); | |
472 | if (set != -1) | |
473 | return set; | |
474 | ||
738cc472 | 475 | /* First see if the actual object referenced is an INDIRECT_REF from a |
8ac61af7 | 476 | restrict-qualified pointer or a "void *". Replace |
738cc472 | 477 | PLACEHOLDER_EXPRs. */ |
8ac61af7 | 478 | while (TREE_CODE (inner) == PLACEHOLDER_EXPR |
738cc472 RK |
479 | || handled_component_p (inner)) |
480 | { | |
481 | if (TREE_CODE (inner) == PLACEHOLDER_EXPR) | |
482 | inner = find_placeholder (inner, &placeholder_ptr); | |
483 | else | |
484 | inner = TREE_OPERAND (inner, 0); | |
8ac61af7 RK |
485 | |
486 | STRIP_NOPS (inner); | |
738cc472 RK |
487 | } |
488 | ||
489 | /* Check for accesses through restrict-qualified pointers. */ | |
490 | if (TREE_CODE (inner) == INDIRECT_REF) | |
491 | { | |
492 | tree decl = find_base_decl (TREE_OPERAND (inner, 0)); | |
493 | ||
494 | if (decl && DECL_POINTER_ALIAS_SET_KNOWN_P (decl)) | |
495 | { | |
e5837c07 | 496 | /* If we haven't computed the actual alias set, do it now. */ |
738cc472 RK |
497 | if (DECL_POINTER_ALIAS_SET (decl) == -2) |
498 | { | |
499 | /* No two restricted pointers can point at the same thing. | |
500 | However, a restricted pointer can point at the same thing | |
501 | as an unrestricted pointer, if that unrestricted pointer | |
502 | is based on the restricted pointer. So, we make the | |
503 | alias set for the restricted pointer a subset of the | |
504 | alias set for the type pointed to by the type of the | |
505 | decl. */ | |
506 | HOST_WIDE_INT pointed_to_alias_set | |
507 | = get_alias_set (TREE_TYPE (TREE_TYPE (decl))); | |
508 | ||
509 | if (pointed_to_alias_set == 0) | |
510 | /* It's not legal to make a subset of alias set zero. */ | |
e7844ffb | 511 | DECL_POINTER_ALIAS_SET (decl) = 0; |
738cc472 RK |
512 | else |
513 | { | |
514 | DECL_POINTER_ALIAS_SET (decl) = new_alias_set (); | |
ca7fd9cd KH |
515 | record_alias_subset (pointed_to_alias_set, |
516 | DECL_POINTER_ALIAS_SET (decl)); | |
738cc472 RK |
517 | } |
518 | } | |
519 | ||
520 | /* We use the alias set indicated in the declaration. */ | |
521 | return DECL_POINTER_ALIAS_SET (decl); | |
522 | } | |
523 | ||
524 | /* If we have an INDIRECT_REF via a void pointer, we don't | |
525 | know anything about what that might alias. */ | |
526 | else if (TREE_CODE (TREE_TYPE (inner)) == VOID_TYPE) | |
527 | return 0; | |
528 | } | |
529 | ||
530 | /* Otherwise, pick up the outermost object that we could have a pointer | |
531 | to, processing conversion and PLACEHOLDER_EXPR as above. */ | |
532 | placeholder_ptr = 0; | |
8ac61af7 | 533 | while (TREE_CODE (t) == PLACEHOLDER_EXPR |
f47e9b4e RK |
534 | || (handled_component_p (t) && ! can_address_p (t))) |
535 | { | |
f47e9b4e | 536 | if (TREE_CODE (t) == PLACEHOLDER_EXPR) |
738cc472 | 537 | t = find_placeholder (t, &placeholder_ptr); |
f47e9b4e RK |
538 | else |
539 | t = TREE_OPERAND (t, 0); | |
f824e5c3 | 540 | |
8ac61af7 RK |
541 | STRIP_NOPS (t); |
542 | } | |
f824e5c3 | 543 | |
738cc472 RK |
544 | /* If we've already determined the alias set for a decl, just return |
545 | it. This is necessary for C++ anonymous unions, whose component | |
546 | variables don't look like union members (boo!). */ | |
5755cd38 JM |
547 | if (TREE_CODE (t) == VAR_DECL |
548 | && DECL_RTL_SET_P (t) && GET_CODE (DECL_RTL (t)) == MEM) | |
549 | return MEM_ALIAS_SET (DECL_RTL (t)); | |
550 | ||
f824e5c3 RK |
551 | /* Now all we care about is the type. */ |
552 | t = TREE_TYPE (t); | |
3bdf5ad1 RK |
553 | } |
554 | ||
3bdf5ad1 RK |
555 | /* Variant qualifiers don't affect the alias set, so get the main |
556 | variant. If this is a type with a known alias set, return it. */ | |
557 | t = TYPE_MAIN_VARIANT (t); | |
738cc472 | 558 | if (TYPE_ALIAS_SET_KNOWN_P (t)) |
3bdf5ad1 RK |
559 | return TYPE_ALIAS_SET (t); |
560 | ||
561 | /* See if the language has special handling for this type. */ | |
8ac61af7 RK |
562 | set = (*lang_hooks.get_alias_set) (t); |
563 | if (set != -1) | |
738cc472 | 564 | return set; |
2bf105ab | 565 | |
3bdf5ad1 RK |
566 | /* There are no objects of FUNCTION_TYPE, so there's no point in |
567 | using up an alias set for them. (There are, of course, pointers | |
568 | and references to functions, but that's different.) */ | |
569 | else if (TREE_CODE (t) == FUNCTION_TYPE) | |
570 | set = 0; | |
74d86f4f RH |
571 | |
572 | /* Unless the language specifies otherwise, let vector types alias | |
573 | their components. This avoids some nasty type punning issues in | |
574 | normal usage. And indeed lets vectors be treated more like an | |
575 | array slice. */ | |
576 | else if (TREE_CODE (t) == VECTOR_TYPE) | |
577 | set = get_alias_set (TREE_TYPE (t)); | |
578 | ||
3bdf5ad1 RK |
579 | else |
580 | /* Otherwise make a new alias set for this type. */ | |
581 | set = new_alias_set (); | |
582 | ||
583 | TYPE_ALIAS_SET (t) = set; | |
2bf105ab RK |
584 | |
585 | /* If this is an aggregate type, we must record any component aliasing | |
586 | information. */ | |
1d79fd2c | 587 | if (AGGREGATE_TYPE_P (t) || TREE_CODE (t) == COMPLEX_TYPE) |
2bf105ab RK |
588 | record_component_aliases (t); |
589 | ||
3bdf5ad1 RK |
590 | return set; |
591 | } | |
592 | ||
593 | /* Return a brand-new alias set. */ | |
594 | ||
f103e34d GK |
595 | static GTY(()) HOST_WIDE_INT last_alias_set; |
596 | ||
3bdf5ad1 | 597 | HOST_WIDE_INT |
4682ae04 | 598 | new_alias_set (void) |
3bdf5ad1 | 599 | { |
3bdf5ad1 | 600 | if (flag_strict_aliasing) |
9ddb66ca | 601 | { |
3416f5c2 JH |
602 | if (!alias_sets) |
603 | VARRAY_GENERIC_PTR_INIT (alias_sets, 10, "alias sets"); | |
604 | else | |
605 | VARRAY_GROW (alias_sets, last_alias_set + 2); | |
9ddb66ca JH |
606 | return ++last_alias_set; |
607 | } | |
3bdf5ad1 RK |
608 | else |
609 | return 0; | |
610 | } | |
3932261a | 611 | |
01d28c3f JM |
612 | /* Indicate that things in SUBSET can alias things in SUPERSET, but that |
613 | not everything that aliases SUPERSET also aliases SUBSET. For example, | |
614 | in C, a store to an `int' can alias a load of a structure containing an | |
615 | `int', and vice versa. But it can't alias a load of a 'double' member | |
616 | of the same structure. Here, the structure would be the SUPERSET and | |
617 | `int' the SUBSET. This relationship is also described in the comment at | |
618 | the beginning of this file. | |
619 | ||
620 | This function should be called only once per SUPERSET/SUBSET pair. | |
3932261a MM |
621 | |
622 | It is illegal for SUPERSET to be zero; everything is implicitly a | |
623 | subset of alias set zero. */ | |
624 | ||
625 | void | |
4682ae04 | 626 | record_alias_subset (HOST_WIDE_INT superset, HOST_WIDE_INT subset) |
3932261a MM |
627 | { |
628 | alias_set_entry superset_entry; | |
629 | alias_set_entry subset_entry; | |
630 | ||
f47e9b4e RK |
631 | /* It is possible in complex type situations for both sets to be the same, |
632 | in which case we can ignore this operation. */ | |
633 | if (superset == subset) | |
634 | return; | |
635 | ||
3932261a MM |
636 | if (superset == 0) |
637 | abort (); | |
638 | ||
639 | superset_entry = get_alias_set_entry (superset); | |
ca7fd9cd | 640 | if (superset_entry == 0) |
3932261a MM |
641 | { |
642 | /* Create an entry for the SUPERSET, so that we have a place to | |
643 | attach the SUBSET. */ | |
b604074c | 644 | superset_entry = ggc_alloc (sizeof (struct alias_set_entry)); |
3932261a | 645 | superset_entry->alias_set = superset; |
ca7fd9cd | 646 | superset_entry->children |
b604074c | 647 | = splay_tree_new_ggc (splay_tree_compare_ints); |
570eb5c8 | 648 | superset_entry->has_zero_child = 0; |
9ddb66ca | 649 | VARRAY_GENERIC_PTR (alias_sets, superset) = superset_entry; |
3932261a MM |
650 | } |
651 | ||
2bf105ab RK |
652 | if (subset == 0) |
653 | superset_entry->has_zero_child = 1; | |
654 | else | |
655 | { | |
656 | subset_entry = get_alias_set_entry (subset); | |
657 | /* If there is an entry for the subset, enter all of its children | |
658 | (if they are not already present) as children of the SUPERSET. */ | |
ca7fd9cd | 659 | if (subset_entry) |
2bf105ab RK |
660 | { |
661 | if (subset_entry->has_zero_child) | |
662 | superset_entry->has_zero_child = 1; | |
d4b60170 | 663 | |
2bf105ab RK |
664 | splay_tree_foreach (subset_entry->children, insert_subset_children, |
665 | superset_entry->children); | |
666 | } | |
3932261a | 667 | |
2bf105ab | 668 | /* Enter the SUBSET itself as a child of the SUPERSET. */ |
ca7fd9cd | 669 | splay_tree_insert (superset_entry->children, |
2bf105ab RK |
670 | (splay_tree_key) subset, 0); |
671 | } | |
3932261a MM |
672 | } |
673 | ||
a0c33338 RK |
674 | /* Record that component types of TYPE, if any, are part of that type for |
675 | aliasing purposes. For record types, we only record component types | |
676 | for fields that are marked addressable. For array types, we always | |
677 | record the component types, so the front end should not call this | |
678 | function if the individual component aren't addressable. */ | |
679 | ||
680 | void | |
4682ae04 | 681 | record_component_aliases (tree type) |
a0c33338 | 682 | { |
3bdf5ad1 | 683 | HOST_WIDE_INT superset = get_alias_set (type); |
a0c33338 RK |
684 | tree field; |
685 | ||
686 | if (superset == 0) | |
687 | return; | |
688 | ||
689 | switch (TREE_CODE (type)) | |
690 | { | |
691 | case ARRAY_TYPE: | |
2bf105ab RK |
692 | if (! TYPE_NONALIASED_COMPONENT (type)) |
693 | record_alias_subset (superset, get_alias_set (TREE_TYPE (type))); | |
a0c33338 RK |
694 | break; |
695 | ||
696 | case RECORD_TYPE: | |
697 | case UNION_TYPE: | |
698 | case QUAL_UNION_TYPE: | |
6614fd40 | 699 | /* Recursively record aliases for the base classes, if there are any. */ |
61eece67 | 700 | if (TYPE_BINFO (type) != NULL && TYPE_BINFO_BASETYPES (type) != NULL) |
ca7fd9cd KH |
701 | { |
702 | int i; | |
703 | for (i = 0; i < TREE_VEC_LENGTH (TYPE_BINFO_BASETYPES (type)); i++) | |
704 | { | |
705 | tree binfo = TREE_VEC_ELT (TYPE_BINFO_BASETYPES (type), i); | |
706 | record_alias_subset (superset, | |
61eece67 | 707 | get_alias_set (BINFO_TYPE (binfo))); |
ca7fd9cd KH |
708 | } |
709 | } | |
a0c33338 | 710 | for (field = TYPE_FIELDS (type); field != 0; field = TREE_CHAIN (field)) |
b16a49a1 | 711 | if (TREE_CODE (field) == FIELD_DECL && ! DECL_NONADDRESSABLE_P (field)) |
2bf105ab | 712 | record_alias_subset (superset, get_alias_set (TREE_TYPE (field))); |
a0c33338 RK |
713 | break; |
714 | ||
1d79fd2c JW |
715 | case COMPLEX_TYPE: |
716 | record_alias_subset (superset, get_alias_set (TREE_TYPE (type))); | |
717 | break; | |
718 | ||
a0c33338 RK |
719 | default: |
720 | break; | |
721 | } | |
722 | } | |
723 | ||
3bdf5ad1 RK |
724 | /* Allocate an alias set for use in storing and reading from the varargs |
725 | spill area. */ | |
726 | ||
f103e34d GK |
727 | static GTY(()) HOST_WIDE_INT varargs_set = -1; |
728 | ||
3bdf5ad1 | 729 | HOST_WIDE_INT |
4682ae04 | 730 | get_varargs_alias_set (void) |
3bdf5ad1 | 731 | { |
f103e34d GK |
732 | if (varargs_set == -1) |
733 | varargs_set = new_alias_set (); | |
3bdf5ad1 | 734 | |
f103e34d | 735 | return varargs_set; |
3bdf5ad1 RK |
736 | } |
737 | ||
738 | /* Likewise, but used for the fixed portions of the frame, e.g., register | |
739 | save areas. */ | |
740 | ||
f103e34d GK |
741 | static GTY(()) HOST_WIDE_INT frame_set = -1; |
742 | ||
3bdf5ad1 | 743 | HOST_WIDE_INT |
4682ae04 | 744 | get_frame_alias_set (void) |
3bdf5ad1 | 745 | { |
f103e34d GK |
746 | if (frame_set == -1) |
747 | frame_set = new_alias_set (); | |
3bdf5ad1 | 748 | |
f103e34d | 749 | return frame_set; |
3bdf5ad1 RK |
750 | } |
751 | ||
2a2c8203 JC |
752 | /* Inside SRC, the source of a SET, find a base address. */ |
753 | ||
9ae8ffe7 | 754 | static rtx |
4682ae04 | 755 | find_base_value (rtx src) |
9ae8ffe7 | 756 | { |
713f41f9 | 757 | unsigned int regno; |
0aacc8ed | 758 | |
9ae8ffe7 JL |
759 | switch (GET_CODE (src)) |
760 | { | |
761 | case SYMBOL_REF: | |
762 | case LABEL_REF: | |
763 | return src; | |
764 | ||
765 | case REG: | |
fb6754f0 | 766 | regno = REGNO (src); |
d4b60170 | 767 | /* At the start of a function, argument registers have known base |
2a2c8203 JC |
768 | values which may be lost later. Returning an ADDRESS |
769 | expression here allows optimization based on argument values | |
770 | even when the argument registers are used for other purposes. */ | |
713f41f9 BS |
771 | if (regno < FIRST_PSEUDO_REGISTER && copying_arguments) |
772 | return new_reg_base_value[regno]; | |
73774bc7 | 773 | |
eaf407a5 | 774 | /* If a pseudo has a known base value, return it. Do not do this |
9b462c42 RH |
775 | for non-fixed hard regs since it can result in a circular |
776 | dependency chain for registers which have values at function entry. | |
eaf407a5 JL |
777 | |
778 | The test above is not sufficient because the scheduler may move | |
779 | a copy out of an arg reg past the NOTE_INSN_FUNCTION_BEGIN. */ | |
9b462c42 | 780 | if ((regno >= FIRST_PSEUDO_REGISTER || fixed_regs[regno]) |
83bbd9b6 RH |
781 | && regno < reg_base_value_size) |
782 | { | |
783 | /* If we're inside init_alias_analysis, use new_reg_base_value | |
784 | to reduce the number of relaxation iterations. */ | |
1afdf91c RH |
785 | if (new_reg_base_value && new_reg_base_value[regno] |
786 | && REG_N_SETS (regno) == 1) | |
83bbd9b6 RH |
787 | return new_reg_base_value[regno]; |
788 | ||
789 | if (reg_base_value[regno]) | |
790 | return reg_base_value[regno]; | |
791 | } | |
73774bc7 | 792 | |
e3f049a8 | 793 | return 0; |
9ae8ffe7 JL |
794 | |
795 | case MEM: | |
796 | /* Check for an argument passed in memory. Only record in the | |
797 | copying-arguments block; it is too hard to track changes | |
798 | otherwise. */ | |
799 | if (copying_arguments | |
800 | && (XEXP (src, 0) == arg_pointer_rtx | |
801 | || (GET_CODE (XEXP (src, 0)) == PLUS | |
802 | && XEXP (XEXP (src, 0), 0) == arg_pointer_rtx))) | |
38a448ca | 803 | return gen_rtx_ADDRESS (VOIDmode, src); |
9ae8ffe7 JL |
804 | return 0; |
805 | ||
806 | case CONST: | |
807 | src = XEXP (src, 0); | |
808 | if (GET_CODE (src) != PLUS && GET_CODE (src) != MINUS) | |
809 | break; | |
d4b60170 | 810 | |
ec5c56db | 811 | /* ... fall through ... */ |
2a2c8203 | 812 | |
9ae8ffe7 JL |
813 | case PLUS: |
814 | case MINUS: | |
2a2c8203 | 815 | { |
ec907dd8 JL |
816 | rtx temp, src_0 = XEXP (src, 0), src_1 = XEXP (src, 1); |
817 | ||
0134bf2d DE |
818 | /* If either operand is a REG that is a known pointer, then it |
819 | is the base. */ | |
820 | if (REG_P (src_0) && REG_POINTER (src_0)) | |
821 | return find_base_value (src_0); | |
822 | if (REG_P (src_1) && REG_POINTER (src_1)) | |
823 | return find_base_value (src_1); | |
824 | ||
ec907dd8 JL |
825 | /* If either operand is a REG, then see if we already have |
826 | a known value for it. */ | |
0134bf2d | 827 | if (REG_P (src_0)) |
ec907dd8 JL |
828 | { |
829 | temp = find_base_value (src_0); | |
d4b60170 | 830 | if (temp != 0) |
ec907dd8 JL |
831 | src_0 = temp; |
832 | } | |
833 | ||
0134bf2d | 834 | if (REG_P (src_1)) |
ec907dd8 JL |
835 | { |
836 | temp = find_base_value (src_1); | |
d4b60170 | 837 | if (temp!= 0) |
ec907dd8 JL |
838 | src_1 = temp; |
839 | } | |
2a2c8203 | 840 | |
0134bf2d DE |
841 | /* If either base is named object or a special address |
842 | (like an argument or stack reference), then use it for the | |
843 | base term. */ | |
844 | if (src_0 != 0 | |
845 | && (GET_CODE (src_0) == SYMBOL_REF | |
846 | || GET_CODE (src_0) == LABEL_REF | |
847 | || (GET_CODE (src_0) == ADDRESS | |
848 | && GET_MODE (src_0) != VOIDmode))) | |
849 | return src_0; | |
850 | ||
851 | if (src_1 != 0 | |
852 | && (GET_CODE (src_1) == SYMBOL_REF | |
853 | || GET_CODE (src_1) == LABEL_REF | |
854 | || (GET_CODE (src_1) == ADDRESS | |
855 | && GET_MODE (src_1) != VOIDmode))) | |
856 | return src_1; | |
857 | ||
d4b60170 | 858 | /* Guess which operand is the base address: |
ec907dd8 JL |
859 | If either operand is a symbol, then it is the base. If |
860 | either operand is a CONST_INT, then the other is the base. */ | |
d4b60170 | 861 | if (GET_CODE (src_1) == CONST_INT || CONSTANT_P (src_0)) |
2a2c8203 | 862 | return find_base_value (src_0); |
d4b60170 | 863 | else if (GET_CODE (src_0) == CONST_INT || CONSTANT_P (src_1)) |
ec907dd8 JL |
864 | return find_base_value (src_1); |
865 | ||
9ae8ffe7 | 866 | return 0; |
2a2c8203 JC |
867 | } |
868 | ||
869 | case LO_SUM: | |
870 | /* The standard form is (lo_sum reg sym) so look only at the | |
871 | second operand. */ | |
872 | return find_base_value (XEXP (src, 1)); | |
9ae8ffe7 JL |
873 | |
874 | case AND: | |
875 | /* If the second operand is constant set the base | |
ec5c56db | 876 | address to the first operand. */ |
2a2c8203 JC |
877 | if (GET_CODE (XEXP (src, 1)) == CONST_INT && INTVAL (XEXP (src, 1)) != 0) |
878 | return find_base_value (XEXP (src, 0)); | |
9ae8ffe7 JL |
879 | return 0; |
880 | ||
61f0131c R |
881 | case TRUNCATE: |
882 | if (GET_MODE_SIZE (GET_MODE (src)) < GET_MODE_SIZE (Pmode)) | |
883 | break; | |
884 | /* Fall through. */ | |
9ae8ffe7 | 885 | case HIGH: |
d288e53d DE |
886 | case PRE_INC: |
887 | case PRE_DEC: | |
888 | case POST_INC: | |
889 | case POST_DEC: | |
890 | case PRE_MODIFY: | |
891 | case POST_MODIFY: | |
2a2c8203 | 892 | return find_base_value (XEXP (src, 0)); |
1d300e19 | 893 | |
0aacc8ed RK |
894 | case ZERO_EXTEND: |
895 | case SIGN_EXTEND: /* used for NT/Alpha pointers */ | |
896 | { | |
897 | rtx temp = find_base_value (XEXP (src, 0)); | |
898 | ||
5ae6cd0d | 899 | if (temp != 0 && CONSTANT_P (temp)) |
0aacc8ed | 900 | temp = convert_memory_address (Pmode, temp); |
0aacc8ed RK |
901 | |
902 | return temp; | |
903 | } | |
904 | ||
1d300e19 KG |
905 | default: |
906 | break; | |
9ae8ffe7 JL |
907 | } |
908 | ||
909 | return 0; | |
910 | } | |
911 | ||
912 | /* Called from init_alias_analysis indirectly through note_stores. */ | |
913 | ||
d4b60170 | 914 | /* While scanning insns to find base values, reg_seen[N] is nonzero if |
9ae8ffe7 JL |
915 | register N has been set in this function. */ |
916 | static char *reg_seen; | |
917 | ||
13309a5f JC |
918 | /* Addresses which are known not to alias anything else are identified |
919 | by a unique integer. */ | |
ec907dd8 JL |
920 | static int unique_id; |
921 | ||
2a2c8203 | 922 | static void |
4682ae04 | 923 | record_set (rtx dest, rtx set, void *data ATTRIBUTE_UNUSED) |
9ae8ffe7 | 924 | { |
b3694847 | 925 | unsigned regno; |
9ae8ffe7 | 926 | rtx src; |
c28b4e40 | 927 | int n; |
9ae8ffe7 JL |
928 | |
929 | if (GET_CODE (dest) != REG) | |
930 | return; | |
931 | ||
fb6754f0 | 932 | regno = REGNO (dest); |
9ae8ffe7 | 933 | |
ac606739 GS |
934 | if (regno >= reg_base_value_size) |
935 | abort (); | |
936 | ||
c28b4e40 JW |
937 | /* If this spans multiple hard registers, then we must indicate that every |
938 | register has an unusable value. */ | |
939 | if (regno < FIRST_PSEUDO_REGISTER) | |
940 | n = HARD_REGNO_NREGS (regno, GET_MODE (dest)); | |
941 | else | |
942 | n = 1; | |
943 | if (n != 1) | |
944 | { | |
945 | while (--n >= 0) | |
946 | { | |
947 | reg_seen[regno + n] = 1; | |
948 | new_reg_base_value[regno + n] = 0; | |
949 | } | |
950 | return; | |
951 | } | |
952 | ||
9ae8ffe7 JL |
953 | if (set) |
954 | { | |
955 | /* A CLOBBER wipes out any old value but does not prevent a previously | |
956 | unset register from acquiring a base address (i.e. reg_seen is not | |
957 | set). */ | |
958 | if (GET_CODE (set) == CLOBBER) | |
959 | { | |
ec907dd8 | 960 | new_reg_base_value[regno] = 0; |
9ae8ffe7 JL |
961 | return; |
962 | } | |
963 | src = SET_SRC (set); | |
964 | } | |
965 | else | |
966 | { | |
9ae8ffe7 JL |
967 | if (reg_seen[regno]) |
968 | { | |
ec907dd8 | 969 | new_reg_base_value[regno] = 0; |
9ae8ffe7 JL |
970 | return; |
971 | } | |
972 | reg_seen[regno] = 1; | |
38a448ca RH |
973 | new_reg_base_value[regno] = gen_rtx_ADDRESS (Pmode, |
974 | GEN_INT (unique_id++)); | |
9ae8ffe7 JL |
975 | return; |
976 | } | |
977 | ||
978 | /* This is not the first set. If the new value is not related to the | |
979 | old value, forget the base value. Note that the following code is | |
980 | not detected: | |
981 | extern int x, y; int *p = &x; p += (&y-&x); | |
982 | ANSI C does not allow computing the difference of addresses | |
983 | of distinct top level objects. */ | |
ec907dd8 | 984 | if (new_reg_base_value[regno]) |
9ae8ffe7 JL |
985 | switch (GET_CODE (src)) |
986 | { | |
2a2c8203 | 987 | case LO_SUM: |
9ae8ffe7 JL |
988 | case MINUS: |
989 | if (XEXP (src, 0) != dest && XEXP (src, 1) != dest) | |
ec907dd8 | 990 | new_reg_base_value[regno] = 0; |
9ae8ffe7 | 991 | break; |
61f0131c R |
992 | case PLUS: |
993 | /* If the value we add in the PLUS is also a valid base value, | |
994 | this might be the actual base value, and the original value | |
995 | an index. */ | |
996 | { | |
997 | rtx other = NULL_RTX; | |
998 | ||
999 | if (XEXP (src, 0) == dest) | |
1000 | other = XEXP (src, 1); | |
1001 | else if (XEXP (src, 1) == dest) | |
1002 | other = XEXP (src, 0); | |
1003 | ||
1004 | if (! other || find_base_value (other)) | |
1005 | new_reg_base_value[regno] = 0; | |
1006 | break; | |
1007 | } | |
9ae8ffe7 JL |
1008 | case AND: |
1009 | if (XEXP (src, 0) != dest || GET_CODE (XEXP (src, 1)) != CONST_INT) | |
ec907dd8 | 1010 | new_reg_base_value[regno] = 0; |
9ae8ffe7 | 1011 | break; |
9ae8ffe7 | 1012 | default: |
ec907dd8 | 1013 | new_reg_base_value[regno] = 0; |
9ae8ffe7 JL |
1014 | break; |
1015 | } | |
1016 | /* If this is the first set of a register, record the value. */ | |
1017 | else if ((regno >= FIRST_PSEUDO_REGISTER || ! fixed_regs[regno]) | |
ec907dd8 JL |
1018 | && ! reg_seen[regno] && new_reg_base_value[regno] == 0) |
1019 | new_reg_base_value[regno] = find_base_value (src); | |
9ae8ffe7 JL |
1020 | |
1021 | reg_seen[regno] = 1; | |
1022 | } | |
1023 | ||
ac3d9668 RK |
1024 | /* Called from loop optimization when a new pseudo-register is |
1025 | created. It indicates that REGNO is being set to VAL. f INVARIANT | |
1026 | is true then this value also describes an invariant relationship | |
1027 | which can be used to deduce that two registers with unknown values | |
1028 | are different. */ | |
d4b60170 | 1029 | |
9ae8ffe7 | 1030 | void |
4682ae04 | 1031 | record_base_value (unsigned int regno, rtx val, int invariant) |
9ae8ffe7 | 1032 | { |
ac3d9668 | 1033 | if (regno >= reg_base_value_size) |
9ae8ffe7 | 1034 | return; |
de12be17 | 1035 | |
de12be17 JC |
1036 | if (invariant && alias_invariant) |
1037 | alias_invariant[regno] = val; | |
1038 | ||
9ae8ffe7 JL |
1039 | if (GET_CODE (val) == REG) |
1040 | { | |
fb6754f0 BS |
1041 | if (REGNO (val) < reg_base_value_size) |
1042 | reg_base_value[regno] = reg_base_value[REGNO (val)]; | |
d4b60170 | 1043 | |
9ae8ffe7 JL |
1044 | return; |
1045 | } | |
d4b60170 | 1046 | |
9ae8ffe7 JL |
1047 | reg_base_value[regno] = find_base_value (val); |
1048 | } | |
1049 | ||
43fe47ca JW |
1050 | /* Clear alias info for a register. This is used if an RTL transformation |
1051 | changes the value of a register. This is used in flow by AUTO_INC_DEC | |
1052 | optimizations. We don't need to clear reg_base_value, since flow only | |
1053 | changes the offset. */ | |
1054 | ||
1055 | void | |
4682ae04 | 1056 | clear_reg_alias_info (rtx reg) |
43fe47ca | 1057 | { |
4e1a4144 JW |
1058 | unsigned int regno = REGNO (reg); |
1059 | ||
1060 | if (regno < reg_known_value_size && regno >= FIRST_PSEUDO_REGISTER) | |
1061 | reg_known_value[regno] = reg; | |
43fe47ca JW |
1062 | } |
1063 | ||
db048faf MM |
1064 | /* Returns a canonical version of X, from the point of view alias |
1065 | analysis. (For example, if X is a MEM whose address is a register, | |
1066 | and the register has a known value (say a SYMBOL_REF), then a MEM | |
1067 | whose address is the SYMBOL_REF is returned.) */ | |
1068 | ||
1069 | rtx | |
4682ae04 | 1070 | canon_rtx (rtx x) |
9ae8ffe7 JL |
1071 | { |
1072 | /* Recursively look for equivalences. */ | |
fb6754f0 BS |
1073 | if (GET_CODE (x) == REG && REGNO (x) >= FIRST_PSEUDO_REGISTER |
1074 | && REGNO (x) < reg_known_value_size) | |
1075 | return reg_known_value[REGNO (x)] == x | |
1076 | ? x : canon_rtx (reg_known_value[REGNO (x)]); | |
9ae8ffe7 JL |
1077 | else if (GET_CODE (x) == PLUS) |
1078 | { | |
1079 | rtx x0 = canon_rtx (XEXP (x, 0)); | |
1080 | rtx x1 = canon_rtx (XEXP (x, 1)); | |
1081 | ||
1082 | if (x0 != XEXP (x, 0) || x1 != XEXP (x, 1)) | |
1083 | { | |
9ae8ffe7 | 1084 | if (GET_CODE (x0) == CONST_INT) |
ed8908e7 | 1085 | return plus_constant (x1, INTVAL (x0)); |
9ae8ffe7 | 1086 | else if (GET_CODE (x1) == CONST_INT) |
ed8908e7 | 1087 | return plus_constant (x0, INTVAL (x1)); |
38a448ca | 1088 | return gen_rtx_PLUS (GET_MODE (x), x0, x1); |
9ae8ffe7 JL |
1089 | } |
1090 | } | |
d4b60170 | 1091 | |
9ae8ffe7 JL |
1092 | /* This gives us much better alias analysis when called from |
1093 | the loop optimizer. Note we want to leave the original | |
1094 | MEM alone, but need to return the canonicalized MEM with | |
1095 | all the flags with their original values. */ | |
1096 | else if (GET_CODE (x) == MEM) | |
f1ec5147 | 1097 | x = replace_equiv_address_nv (x, canon_rtx (XEXP (x, 0))); |
d4b60170 | 1098 | |
9ae8ffe7 JL |
1099 | return x; |
1100 | } | |
1101 | ||
1102 | /* Return 1 if X and Y are identical-looking rtx's. | |
45183e03 | 1103 | Expect that X and Y has been already canonicalized. |
9ae8ffe7 JL |
1104 | |
1105 | We use the data in reg_known_value above to see if two registers with | |
1106 | different numbers are, in fact, equivalent. */ | |
1107 | ||
1108 | static int | |
4682ae04 | 1109 | rtx_equal_for_memref_p (rtx x, rtx y) |
9ae8ffe7 | 1110 | { |
b3694847 SS |
1111 | int i; |
1112 | int j; | |
1113 | enum rtx_code code; | |
1114 | const char *fmt; | |
9ae8ffe7 JL |
1115 | |
1116 | if (x == 0 && y == 0) | |
1117 | return 1; | |
1118 | if (x == 0 || y == 0) | |
1119 | return 0; | |
d4b60170 | 1120 | |
9ae8ffe7 JL |
1121 | if (x == y) |
1122 | return 1; | |
1123 | ||
1124 | code = GET_CODE (x); | |
1125 | /* Rtx's of different codes cannot be equal. */ | |
1126 | if (code != GET_CODE (y)) | |
1127 | return 0; | |
1128 | ||
1129 | /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. | |
1130 | (REG:SI x) and (REG:HI x) are NOT equivalent. */ | |
1131 | ||
1132 | if (GET_MODE (x) != GET_MODE (y)) | |
1133 | return 0; | |
1134 | ||
db048faf MM |
1135 | /* Some RTL can be compared without a recursive examination. */ |
1136 | switch (code) | |
1137 | { | |
ab59db3c BS |
1138 | case VALUE: |
1139 | return CSELIB_VAL_PTR (x) == CSELIB_VAL_PTR (y); | |
1140 | ||
db048faf MM |
1141 | case REG: |
1142 | return REGNO (x) == REGNO (y); | |
1143 | ||
1144 | case LABEL_REF: | |
1145 | return XEXP (x, 0) == XEXP (y, 0); | |
ca7fd9cd | 1146 | |
db048faf MM |
1147 | case SYMBOL_REF: |
1148 | return XSTR (x, 0) == XSTR (y, 0); | |
1149 | ||
1150 | case CONST_INT: | |
1151 | case CONST_DOUBLE: | |
1152 | /* There's no need to compare the contents of CONST_DOUBLEs or | |
1153 | CONST_INTs because pointer equality is a good enough | |
1154 | comparison for these nodes. */ | |
1155 | return 0; | |
1156 | ||
1157 | case ADDRESSOF: | |
831ecbd4 | 1158 | return (XINT (x, 1) == XINT (y, 1) |
45183e03 | 1159 | && rtx_equal_for_memref_p (XEXP (x, 0), |
4682ae04 | 1160 | XEXP (y, 0))); |
db048faf MM |
1161 | |
1162 | default: | |
1163 | break; | |
1164 | } | |
9ae8ffe7 | 1165 | |
45183e03 JH |
1166 | /* canon_rtx knows how to handle plus. No need to canonicalize. */ |
1167 | if (code == PLUS) | |
9ae8ffe7 JL |
1168 | return ((rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 0)) |
1169 | && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 1))) | |
1170 | || (rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 1)) | |
1171 | && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 0)))); | |
45183e03 JH |
1172 | /* For commutative operations, the RTX match if the operand match in any |
1173 | order. Also handle the simple binary and unary cases without a loop. */ | |
1174 | if (code == EQ || code == NE || GET_RTX_CLASS (code) == 'c') | |
1175 | { | |
1176 | rtx xop0 = canon_rtx (XEXP (x, 0)); | |
1177 | rtx yop0 = canon_rtx (XEXP (y, 0)); | |
1178 | rtx yop1 = canon_rtx (XEXP (y, 1)); | |
1179 | ||
1180 | return ((rtx_equal_for_memref_p (xop0, yop0) | |
1181 | && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), yop1)) | |
1182 | || (rtx_equal_for_memref_p (xop0, yop1) | |
1183 | && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), yop0))); | |
1184 | } | |
9ae8ffe7 | 1185 | else if (GET_RTX_CLASS (code) == '<' || GET_RTX_CLASS (code) == '2') |
45183e03 JH |
1186 | { |
1187 | return (rtx_equal_for_memref_p (canon_rtx (XEXP (x, 0)), | |
4682ae04 | 1188 | canon_rtx (XEXP (y, 0))) |
45183e03 JH |
1189 | && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), |
1190 | canon_rtx (XEXP (y, 1)))); | |
1191 | } | |
9ae8ffe7 | 1192 | else if (GET_RTX_CLASS (code) == '1') |
45183e03 | 1193 | return rtx_equal_for_memref_p (canon_rtx (XEXP (x, 0)), |
4682ae04 | 1194 | canon_rtx (XEXP (y, 0))); |
9ae8ffe7 JL |
1195 | |
1196 | /* Compare the elements. If any pair of corresponding elements | |
de12be17 JC |
1197 | fail to match, return 0 for the whole things. |
1198 | ||
1199 | Limit cases to types which actually appear in addresses. */ | |
9ae8ffe7 JL |
1200 | |
1201 | fmt = GET_RTX_FORMAT (code); | |
1202 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
1203 | { | |
1204 | switch (fmt[i]) | |
1205 | { | |
9ae8ffe7 JL |
1206 | case 'i': |
1207 | if (XINT (x, i) != XINT (y, i)) | |
1208 | return 0; | |
1209 | break; | |
1210 | ||
9ae8ffe7 JL |
1211 | case 'E': |
1212 | /* Two vectors must have the same length. */ | |
1213 | if (XVECLEN (x, i) != XVECLEN (y, i)) | |
1214 | return 0; | |
1215 | ||
1216 | /* And the corresponding elements must match. */ | |
1217 | for (j = 0; j < XVECLEN (x, i); j++) | |
45183e03 JH |
1218 | if (rtx_equal_for_memref_p (canon_rtx (XVECEXP (x, i, j)), |
1219 | canon_rtx (XVECEXP (y, i, j))) == 0) | |
9ae8ffe7 JL |
1220 | return 0; |
1221 | break; | |
1222 | ||
1223 | case 'e': | |
45183e03 JH |
1224 | if (rtx_equal_for_memref_p (canon_rtx (XEXP (x, i)), |
1225 | canon_rtx (XEXP (y, i))) == 0) | |
9ae8ffe7 JL |
1226 | return 0; |
1227 | break; | |
1228 | ||
3237ac18 AH |
1229 | /* This can happen for asm operands. */ |
1230 | case 's': | |
1231 | if (strcmp (XSTR (x, i), XSTR (y, i))) | |
1232 | return 0; | |
1233 | break; | |
1234 | ||
aee21ba9 JL |
1235 | /* This can happen for an asm which clobbers memory. */ |
1236 | case '0': | |
1237 | break; | |
1238 | ||
9ae8ffe7 JL |
1239 | /* It is believed that rtx's at this level will never |
1240 | contain anything but integers and other rtx's, | |
1241 | except for within LABEL_REFs and SYMBOL_REFs. */ | |
1242 | default: | |
1243 | abort (); | |
1244 | } | |
1245 | } | |
1246 | return 1; | |
1247 | } | |
1248 | ||
1249 | /* Given an rtx X, find a SYMBOL_REF or LABEL_REF within | |
1250 | X and return it, or return 0 if none found. */ | |
1251 | ||
1252 | static rtx | |
4682ae04 | 1253 | find_symbolic_term (rtx x) |
9ae8ffe7 | 1254 | { |
b3694847 SS |
1255 | int i; |
1256 | enum rtx_code code; | |
1257 | const char *fmt; | |
9ae8ffe7 JL |
1258 | |
1259 | code = GET_CODE (x); | |
1260 | if (code == SYMBOL_REF || code == LABEL_REF) | |
1261 | return x; | |
1262 | if (GET_RTX_CLASS (code) == 'o') | |
1263 | return 0; | |
1264 | ||
1265 | fmt = GET_RTX_FORMAT (code); | |
1266 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
1267 | { | |
1268 | rtx t; | |
1269 | ||
1270 | if (fmt[i] == 'e') | |
1271 | { | |
1272 | t = find_symbolic_term (XEXP (x, i)); | |
1273 | if (t != 0) | |
1274 | return t; | |
1275 | } | |
1276 | else if (fmt[i] == 'E') | |
1277 | break; | |
1278 | } | |
1279 | return 0; | |
1280 | } | |
1281 | ||
94f24ddc | 1282 | rtx |
4682ae04 | 1283 | find_base_term (rtx x) |
9ae8ffe7 | 1284 | { |
eab5c70a BS |
1285 | cselib_val *val; |
1286 | struct elt_loc_list *l; | |
1287 | ||
b949ea8b JW |
1288 | #if defined (FIND_BASE_TERM) |
1289 | /* Try machine-dependent ways to find the base term. */ | |
1290 | x = FIND_BASE_TERM (x); | |
1291 | #endif | |
1292 | ||
9ae8ffe7 JL |
1293 | switch (GET_CODE (x)) |
1294 | { | |
1295 | case REG: | |
1296 | return REG_BASE_VALUE (x); | |
1297 | ||
d288e53d DE |
1298 | case TRUNCATE: |
1299 | if (GET_MODE_SIZE (GET_MODE (x)) < GET_MODE_SIZE (Pmode)) | |
ca7fd9cd | 1300 | return 0; |
d288e53d | 1301 | /* Fall through. */ |
9ae8ffe7 | 1302 | case HIGH: |
6d849a2a JL |
1303 | case PRE_INC: |
1304 | case PRE_DEC: | |
1305 | case POST_INC: | |
1306 | case POST_DEC: | |
d288e53d DE |
1307 | case PRE_MODIFY: |
1308 | case POST_MODIFY: | |
6d849a2a JL |
1309 | return find_base_term (XEXP (x, 0)); |
1310 | ||
1abade85 RK |
1311 | case ZERO_EXTEND: |
1312 | case SIGN_EXTEND: /* Used for Alpha/NT pointers */ | |
1313 | { | |
1314 | rtx temp = find_base_term (XEXP (x, 0)); | |
1315 | ||
5ae6cd0d | 1316 | if (temp != 0 && CONSTANT_P (temp)) |
1abade85 | 1317 | temp = convert_memory_address (Pmode, temp); |
1abade85 RK |
1318 | |
1319 | return temp; | |
1320 | } | |
1321 | ||
eab5c70a BS |
1322 | case VALUE: |
1323 | val = CSELIB_VAL_PTR (x); | |
1324 | for (l = val->locs; l; l = l->next) | |
1325 | if ((x = find_base_term (l->loc)) != 0) | |
1326 | return x; | |
1327 | return 0; | |
1328 | ||
9ae8ffe7 JL |
1329 | case CONST: |
1330 | x = XEXP (x, 0); | |
1331 | if (GET_CODE (x) != PLUS && GET_CODE (x) != MINUS) | |
1332 | return 0; | |
938d968e | 1333 | /* Fall through. */ |
9ae8ffe7 JL |
1334 | case LO_SUM: |
1335 | case PLUS: | |
1336 | case MINUS: | |
1337 | { | |
3c567fae JL |
1338 | rtx tmp1 = XEXP (x, 0); |
1339 | rtx tmp2 = XEXP (x, 1); | |
1340 | ||
f5143c46 | 1341 | /* This is a little bit tricky since we have to determine which of |
3c567fae JL |
1342 | the two operands represents the real base address. Otherwise this |
1343 | routine may return the index register instead of the base register. | |
1344 | ||
1345 | That may cause us to believe no aliasing was possible, when in | |
1346 | fact aliasing is possible. | |
1347 | ||
1348 | We use a few simple tests to guess the base register. Additional | |
1349 | tests can certainly be added. For example, if one of the operands | |
1350 | is a shift or multiply, then it must be the index register and the | |
1351 | other operand is the base register. */ | |
ca7fd9cd | 1352 | |
b949ea8b JW |
1353 | if (tmp1 == pic_offset_table_rtx && CONSTANT_P (tmp2)) |
1354 | return find_base_term (tmp2); | |
1355 | ||
3c567fae JL |
1356 | /* If either operand is known to be a pointer, then use it |
1357 | to determine the base term. */ | |
3502dc9c | 1358 | if (REG_P (tmp1) && REG_POINTER (tmp1)) |
3c567fae JL |
1359 | return find_base_term (tmp1); |
1360 | ||
3502dc9c | 1361 | if (REG_P (tmp2) && REG_POINTER (tmp2)) |
3c567fae JL |
1362 | return find_base_term (tmp2); |
1363 | ||
1364 | /* Neither operand was known to be a pointer. Go ahead and find the | |
1365 | base term for both operands. */ | |
1366 | tmp1 = find_base_term (tmp1); | |
1367 | tmp2 = find_base_term (tmp2); | |
1368 | ||
1369 | /* If either base term is named object or a special address | |
1370 | (like an argument or stack reference), then use it for the | |
1371 | base term. */ | |
d4b60170 | 1372 | if (tmp1 != 0 |
3c567fae JL |
1373 | && (GET_CODE (tmp1) == SYMBOL_REF |
1374 | || GET_CODE (tmp1) == LABEL_REF | |
1375 | || (GET_CODE (tmp1) == ADDRESS | |
1376 | && GET_MODE (tmp1) != VOIDmode))) | |
1377 | return tmp1; | |
1378 | ||
d4b60170 | 1379 | if (tmp2 != 0 |
3c567fae JL |
1380 | && (GET_CODE (tmp2) == SYMBOL_REF |
1381 | || GET_CODE (tmp2) == LABEL_REF | |
1382 | || (GET_CODE (tmp2) == ADDRESS | |
1383 | && GET_MODE (tmp2) != VOIDmode))) | |
1384 | return tmp2; | |
1385 | ||
1386 | /* We could not determine which of the two operands was the | |
1387 | base register and which was the index. So we can determine | |
1388 | nothing from the base alias check. */ | |
1389 | return 0; | |
9ae8ffe7 JL |
1390 | } |
1391 | ||
1392 | case AND: | |
d288e53d DE |
1393 | if (GET_CODE (XEXP (x, 1)) == CONST_INT && INTVAL (XEXP (x, 1)) != 0) |
1394 | return find_base_term (XEXP (x, 0)); | |
9ae8ffe7 JL |
1395 | return 0; |
1396 | ||
1397 | case SYMBOL_REF: | |
1398 | case LABEL_REF: | |
1399 | return x; | |
1400 | ||
d982e46e | 1401 | case ADDRESSOF: |
bb07060a | 1402 | return REG_BASE_VALUE (frame_pointer_rtx); |
d982e46e | 1403 | |
9ae8ffe7 JL |
1404 | default: |
1405 | return 0; | |
1406 | } | |
1407 | } | |
1408 | ||
1409 | /* Return 0 if the addresses X and Y are known to point to different | |
1410 | objects, 1 if they might be pointers to the same object. */ | |
1411 | ||
1412 | static int | |
4682ae04 AJ |
1413 | base_alias_check (rtx x, rtx y, enum machine_mode x_mode, |
1414 | enum machine_mode y_mode) | |
9ae8ffe7 JL |
1415 | { |
1416 | rtx x_base = find_base_term (x); | |
1417 | rtx y_base = find_base_term (y); | |
1418 | ||
1c72c7f6 JC |
1419 | /* If the address itself has no known base see if a known equivalent |
1420 | value has one. If either address still has no known base, nothing | |
1421 | is known about aliasing. */ | |
1422 | if (x_base == 0) | |
1423 | { | |
1424 | rtx x_c; | |
d4b60170 | 1425 | |
1c72c7f6 JC |
1426 | if (! flag_expensive_optimizations || (x_c = canon_rtx (x)) == x) |
1427 | return 1; | |
d4b60170 | 1428 | |
1c72c7f6 JC |
1429 | x_base = find_base_term (x_c); |
1430 | if (x_base == 0) | |
1431 | return 1; | |
1432 | } | |
9ae8ffe7 | 1433 | |
1c72c7f6 JC |
1434 | if (y_base == 0) |
1435 | { | |
1436 | rtx y_c; | |
1437 | if (! flag_expensive_optimizations || (y_c = canon_rtx (y)) == y) | |
1438 | return 1; | |
d4b60170 | 1439 | |
1c72c7f6 JC |
1440 | y_base = find_base_term (y_c); |
1441 | if (y_base == 0) | |
1442 | return 1; | |
1443 | } | |
1444 | ||
1445 | /* If the base addresses are equal nothing is known about aliasing. */ | |
1446 | if (rtx_equal_p (x_base, y_base)) | |
9ae8ffe7 JL |
1447 | return 1; |
1448 | ||
ca7fd9cd | 1449 | /* The base addresses of the read and write are different expressions. |
56ee9281 RH |
1450 | If they are both symbols and they are not accessed via AND, there is |
1451 | no conflict. We can bring knowledge of object alignment into play | |
1452 | here. For example, on alpha, "char a, b;" can alias one another, | |
1453 | though "char a; long b;" cannot. */ | |
9ae8ffe7 | 1454 | if (GET_CODE (x_base) != ADDRESS && GET_CODE (y_base) != ADDRESS) |
c02f035f | 1455 | { |
56ee9281 RH |
1456 | if (GET_CODE (x) == AND && GET_CODE (y) == AND) |
1457 | return 1; | |
1458 | if (GET_CODE (x) == AND | |
1459 | && (GET_CODE (XEXP (x, 1)) != CONST_INT | |
8fa2140d | 1460 | || (int) GET_MODE_UNIT_SIZE (y_mode) < -INTVAL (XEXP (x, 1)))) |
56ee9281 RH |
1461 | return 1; |
1462 | if (GET_CODE (y) == AND | |
1463 | && (GET_CODE (XEXP (y, 1)) != CONST_INT | |
8fa2140d | 1464 | || (int) GET_MODE_UNIT_SIZE (x_mode) < -INTVAL (XEXP (y, 1)))) |
56ee9281 | 1465 | return 1; |
b2972551 JL |
1466 | /* Differing symbols never alias. */ |
1467 | return 0; | |
c02f035f | 1468 | } |
9ae8ffe7 JL |
1469 | |
1470 | /* If one address is a stack reference there can be no alias: | |
1471 | stack references using different base registers do not alias, | |
1472 | a stack reference can not alias a parameter, and a stack reference | |
1473 | can not alias a global. */ | |
1474 | if ((GET_CODE (x_base) == ADDRESS && GET_MODE (x_base) == Pmode) | |
1475 | || (GET_CODE (y_base) == ADDRESS && GET_MODE (y_base) == Pmode)) | |
1476 | return 0; | |
1477 | ||
1478 | if (! flag_argument_noalias) | |
1479 | return 1; | |
1480 | ||
1481 | if (flag_argument_noalias > 1) | |
1482 | return 0; | |
1483 | ||
ec5c56db | 1484 | /* Weak noalias assertion (arguments are distinct, but may match globals). */ |
9ae8ffe7 JL |
1485 | return ! (GET_MODE (x_base) == VOIDmode && GET_MODE (y_base) == VOIDmode); |
1486 | } | |
1487 | ||
eab5c70a BS |
1488 | /* Convert the address X into something we can use. This is done by returning |
1489 | it unchanged unless it is a value; in the latter case we call cselib to get | |
1490 | a more useful rtx. */ | |
3bdf5ad1 | 1491 | |
a13d4ebf | 1492 | rtx |
4682ae04 | 1493 | get_addr (rtx x) |
eab5c70a BS |
1494 | { |
1495 | cselib_val *v; | |
1496 | struct elt_loc_list *l; | |
1497 | ||
1498 | if (GET_CODE (x) != VALUE) | |
1499 | return x; | |
1500 | v = CSELIB_VAL_PTR (x); | |
1501 | for (l = v->locs; l; l = l->next) | |
1502 | if (CONSTANT_P (l->loc)) | |
1503 | return l->loc; | |
1504 | for (l = v->locs; l; l = l->next) | |
1505 | if (GET_CODE (l->loc) != REG && GET_CODE (l->loc) != MEM) | |
1506 | return l->loc; | |
1507 | if (v->locs) | |
1508 | return v->locs->loc; | |
1509 | return x; | |
1510 | } | |
1511 | ||
39cec1ac MH |
1512 | /* Return the address of the (N_REFS + 1)th memory reference to ADDR |
1513 | where SIZE is the size in bytes of the memory reference. If ADDR | |
1514 | is not modified by the memory reference then ADDR is returned. */ | |
1515 | ||
1516 | rtx | |
4682ae04 | 1517 | addr_side_effect_eval (rtx addr, int size, int n_refs) |
39cec1ac MH |
1518 | { |
1519 | int offset = 0; | |
ca7fd9cd | 1520 | |
39cec1ac MH |
1521 | switch (GET_CODE (addr)) |
1522 | { | |
1523 | case PRE_INC: | |
1524 | offset = (n_refs + 1) * size; | |
1525 | break; | |
1526 | case PRE_DEC: | |
1527 | offset = -(n_refs + 1) * size; | |
1528 | break; | |
1529 | case POST_INC: | |
1530 | offset = n_refs * size; | |
1531 | break; | |
1532 | case POST_DEC: | |
1533 | offset = -n_refs * size; | |
1534 | break; | |
1535 | ||
1536 | default: | |
1537 | return addr; | |
1538 | } | |
ca7fd9cd | 1539 | |
39cec1ac | 1540 | if (offset) |
45183e03 JH |
1541 | addr = gen_rtx_PLUS (GET_MODE (addr), XEXP (addr, 0), |
1542 | GEN_INT (offset)); | |
39cec1ac MH |
1543 | else |
1544 | addr = XEXP (addr, 0); | |
45183e03 | 1545 | addr = canon_rtx (addr); |
39cec1ac MH |
1546 | |
1547 | return addr; | |
1548 | } | |
1549 | ||
9ae8ffe7 JL |
1550 | /* Return nonzero if X and Y (memory addresses) could reference the |
1551 | same location in memory. C is an offset accumulator. When | |
1552 | C is nonzero, we are testing aliases between X and Y + C. | |
1553 | XSIZE is the size in bytes of the X reference, | |
1554 | similarly YSIZE is the size in bytes for Y. | |
45183e03 | 1555 | Expect that canon_rtx has been already called for X and Y. |
9ae8ffe7 JL |
1556 | |
1557 | If XSIZE or YSIZE is zero, we do not know the amount of memory being | |
1558 | referenced (the reference was BLKmode), so make the most pessimistic | |
1559 | assumptions. | |
1560 | ||
c02f035f RH |
1561 | If XSIZE or YSIZE is negative, we may access memory outside the object |
1562 | being referenced as a side effect. This can happen when using AND to | |
1563 | align memory references, as is done on the Alpha. | |
1564 | ||
9ae8ffe7 | 1565 | Nice to notice that varying addresses cannot conflict with fp if no |
0211b6ab | 1566 | local variables had their addresses taken, but that's too hard now. */ |
9ae8ffe7 | 1567 | |
9ae8ffe7 | 1568 | static int |
4682ae04 | 1569 | memrefs_conflict_p (int xsize, rtx x, int ysize, rtx y, HOST_WIDE_INT c) |
9ae8ffe7 | 1570 | { |
eab5c70a BS |
1571 | if (GET_CODE (x) == VALUE) |
1572 | x = get_addr (x); | |
1573 | if (GET_CODE (y) == VALUE) | |
1574 | y = get_addr (y); | |
9ae8ffe7 JL |
1575 | if (GET_CODE (x) == HIGH) |
1576 | x = XEXP (x, 0); | |
1577 | else if (GET_CODE (x) == LO_SUM) | |
1578 | x = XEXP (x, 1); | |
1579 | else | |
45183e03 | 1580 | x = addr_side_effect_eval (x, xsize, 0); |
9ae8ffe7 JL |
1581 | if (GET_CODE (y) == HIGH) |
1582 | y = XEXP (y, 0); | |
1583 | else if (GET_CODE (y) == LO_SUM) | |
1584 | y = XEXP (y, 1); | |
1585 | else | |
45183e03 | 1586 | y = addr_side_effect_eval (y, ysize, 0); |
9ae8ffe7 JL |
1587 | |
1588 | if (rtx_equal_for_memref_p (x, y)) | |
1589 | { | |
c02f035f | 1590 | if (xsize <= 0 || ysize <= 0) |
9ae8ffe7 JL |
1591 | return 1; |
1592 | if (c >= 0 && xsize > c) | |
1593 | return 1; | |
1594 | if (c < 0 && ysize+c > 0) | |
1595 | return 1; | |
1596 | return 0; | |
1597 | } | |
1598 | ||
6e73e666 JC |
1599 | /* This code used to check for conflicts involving stack references and |
1600 | globals but the base address alias code now handles these cases. */ | |
9ae8ffe7 JL |
1601 | |
1602 | if (GET_CODE (x) == PLUS) | |
1603 | { | |
1604 | /* The fact that X is canonicalized means that this | |
1605 | PLUS rtx is canonicalized. */ | |
1606 | rtx x0 = XEXP (x, 0); | |
1607 | rtx x1 = XEXP (x, 1); | |
1608 | ||
1609 | if (GET_CODE (y) == PLUS) | |
1610 | { | |
1611 | /* The fact that Y is canonicalized means that this | |
1612 | PLUS rtx is canonicalized. */ | |
1613 | rtx y0 = XEXP (y, 0); | |
1614 | rtx y1 = XEXP (y, 1); | |
1615 | ||
1616 | if (rtx_equal_for_memref_p (x1, y1)) | |
1617 | return memrefs_conflict_p (xsize, x0, ysize, y0, c); | |
1618 | if (rtx_equal_for_memref_p (x0, y0)) | |
1619 | return memrefs_conflict_p (xsize, x1, ysize, y1, c); | |
1620 | if (GET_CODE (x1) == CONST_INT) | |
63be02db JM |
1621 | { |
1622 | if (GET_CODE (y1) == CONST_INT) | |
1623 | return memrefs_conflict_p (xsize, x0, ysize, y0, | |
1624 | c - INTVAL (x1) + INTVAL (y1)); | |
1625 | else | |
1626 | return memrefs_conflict_p (xsize, x0, ysize, y, | |
1627 | c - INTVAL (x1)); | |
1628 | } | |
9ae8ffe7 JL |
1629 | else if (GET_CODE (y1) == CONST_INT) |
1630 | return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1)); | |
1631 | ||
6e73e666 | 1632 | return 1; |
9ae8ffe7 JL |
1633 | } |
1634 | else if (GET_CODE (x1) == CONST_INT) | |
1635 | return memrefs_conflict_p (xsize, x0, ysize, y, c - INTVAL (x1)); | |
1636 | } | |
1637 | else if (GET_CODE (y) == PLUS) | |
1638 | { | |
1639 | /* The fact that Y is canonicalized means that this | |
1640 | PLUS rtx is canonicalized. */ | |
1641 | rtx y0 = XEXP (y, 0); | |
1642 | rtx y1 = XEXP (y, 1); | |
1643 | ||
1644 | if (GET_CODE (y1) == CONST_INT) | |
1645 | return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1)); | |
1646 | else | |
1647 | return 1; | |
1648 | } | |
1649 | ||
1650 | if (GET_CODE (x) == GET_CODE (y)) | |
1651 | switch (GET_CODE (x)) | |
1652 | { | |
1653 | case MULT: | |
1654 | { | |
1655 | /* Handle cases where we expect the second operands to be the | |
1656 | same, and check only whether the first operand would conflict | |
1657 | or not. */ | |
1658 | rtx x0, y0; | |
1659 | rtx x1 = canon_rtx (XEXP (x, 1)); | |
1660 | rtx y1 = canon_rtx (XEXP (y, 1)); | |
1661 | if (! rtx_equal_for_memref_p (x1, y1)) | |
1662 | return 1; | |
1663 | x0 = canon_rtx (XEXP (x, 0)); | |
1664 | y0 = canon_rtx (XEXP (y, 0)); | |
1665 | if (rtx_equal_for_memref_p (x0, y0)) | |
1666 | return (xsize == 0 || ysize == 0 | |
1667 | || (c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)); | |
1668 | ||
1669 | /* Can't properly adjust our sizes. */ | |
1670 | if (GET_CODE (x1) != CONST_INT) | |
1671 | return 1; | |
1672 | xsize /= INTVAL (x1); | |
1673 | ysize /= INTVAL (x1); | |
1674 | c /= INTVAL (x1); | |
1675 | return memrefs_conflict_p (xsize, x0, ysize, y0, c); | |
1676 | } | |
1d300e19 | 1677 | |
de12be17 JC |
1678 | case REG: |
1679 | /* Are these registers known not to be equal? */ | |
1680 | if (alias_invariant) | |
1681 | { | |
e51712db | 1682 | unsigned int r_x = REGNO (x), r_y = REGNO (y); |
de12be17 JC |
1683 | rtx i_x, i_y; /* invariant relationships of X and Y */ |
1684 | ||
1685 | i_x = r_x >= reg_base_value_size ? 0 : alias_invariant[r_x]; | |
1686 | i_y = r_y >= reg_base_value_size ? 0 : alias_invariant[r_y]; | |
1687 | ||
1688 | if (i_x == 0 && i_y == 0) | |
1689 | break; | |
1690 | ||
1691 | if (! memrefs_conflict_p (xsize, i_x ? i_x : x, | |
1692 | ysize, i_y ? i_y : y, c)) | |
1693 | return 0; | |
1694 | } | |
1695 | break; | |
1696 | ||
1d300e19 KG |
1697 | default: |
1698 | break; | |
9ae8ffe7 JL |
1699 | } |
1700 | ||
1701 | /* Treat an access through an AND (e.g. a subword access on an Alpha) | |
ca7fd9cd | 1702 | as an access with indeterminate size. Assume that references |
56ee9281 RH |
1703 | besides AND are aligned, so if the size of the other reference is |
1704 | at least as large as the alignment, assume no other overlap. */ | |
9ae8ffe7 | 1705 | if (GET_CODE (x) == AND && GET_CODE (XEXP (x, 1)) == CONST_INT) |
56ee9281 | 1706 | { |
02e3377d | 1707 | if (GET_CODE (y) == AND || ysize < -INTVAL (XEXP (x, 1))) |
56ee9281 | 1708 | xsize = -1; |
45183e03 | 1709 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), ysize, y, c); |
56ee9281 | 1710 | } |
9ae8ffe7 | 1711 | if (GET_CODE (y) == AND && GET_CODE (XEXP (y, 1)) == CONST_INT) |
c02f035f | 1712 | { |
56ee9281 | 1713 | /* ??? If we are indexing far enough into the array/structure, we |
ca7fd9cd | 1714 | may yet be able to determine that we can not overlap. But we |
c02f035f | 1715 | also need to that we are far enough from the end not to overlap |
56ee9281 | 1716 | a following reference, so we do nothing with that for now. */ |
02e3377d | 1717 | if (GET_CODE (x) == AND || xsize < -INTVAL (XEXP (y, 1))) |
56ee9281 | 1718 | ysize = -1; |
45183e03 | 1719 | return memrefs_conflict_p (xsize, x, ysize, canon_rtx (XEXP (y, 0)), c); |
c02f035f | 1720 | } |
9ae8ffe7 | 1721 | |
b24ea077 JW |
1722 | if (GET_CODE (x) == ADDRESSOF) |
1723 | { | |
1724 | if (y == frame_pointer_rtx | |
1725 | || GET_CODE (y) == ADDRESSOF) | |
1726 | return xsize <= 0 || ysize <= 0; | |
1727 | } | |
1728 | if (GET_CODE (y) == ADDRESSOF) | |
1729 | { | |
1730 | if (x == frame_pointer_rtx) | |
1731 | return xsize <= 0 || ysize <= 0; | |
1732 | } | |
d982e46e | 1733 | |
9ae8ffe7 JL |
1734 | if (CONSTANT_P (x)) |
1735 | { | |
1736 | if (GET_CODE (x) == CONST_INT && GET_CODE (y) == CONST_INT) | |
1737 | { | |
1738 | c += (INTVAL (y) - INTVAL (x)); | |
c02f035f | 1739 | return (xsize <= 0 || ysize <= 0 |
9ae8ffe7 JL |
1740 | || (c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)); |
1741 | } | |
1742 | ||
1743 | if (GET_CODE (x) == CONST) | |
1744 | { | |
1745 | if (GET_CODE (y) == CONST) | |
1746 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), | |
1747 | ysize, canon_rtx (XEXP (y, 0)), c); | |
1748 | else | |
1749 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), | |
1750 | ysize, y, c); | |
1751 | } | |
1752 | if (GET_CODE (y) == CONST) | |
1753 | return memrefs_conflict_p (xsize, x, ysize, | |
1754 | canon_rtx (XEXP (y, 0)), c); | |
1755 | ||
1756 | if (CONSTANT_P (y)) | |
b949ea8b | 1757 | return (xsize <= 0 || ysize <= 0 |
c02f035f | 1758 | || (rtx_equal_for_memref_p (x, y) |
b949ea8b | 1759 | && ((c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)))); |
9ae8ffe7 JL |
1760 | |
1761 | return 1; | |
1762 | } | |
1763 | return 1; | |
1764 | } | |
1765 | ||
1766 | /* Functions to compute memory dependencies. | |
1767 | ||
1768 | Since we process the insns in execution order, we can build tables | |
1769 | to keep track of what registers are fixed (and not aliased), what registers | |
1770 | are varying in known ways, and what registers are varying in unknown | |
1771 | ways. | |
1772 | ||
1773 | If both memory references are volatile, then there must always be a | |
1774 | dependence between the two references, since their order can not be | |
1775 | changed. A volatile and non-volatile reference can be interchanged | |
ca7fd9cd | 1776 | though. |
9ae8ffe7 | 1777 | |
dc1618bc RK |
1778 | A MEM_IN_STRUCT reference at a non-AND varying address can never |
1779 | conflict with a non-MEM_IN_STRUCT reference at a fixed address. We | |
1780 | also must allow AND addresses, because they may generate accesses | |
1781 | outside the object being referenced. This is used to generate | |
1782 | aligned addresses from unaligned addresses, for instance, the alpha | |
1783 | storeqi_unaligned pattern. */ | |
9ae8ffe7 JL |
1784 | |
1785 | /* Read dependence: X is read after read in MEM takes place. There can | |
1786 | only be a dependence here if both reads are volatile. */ | |
1787 | ||
1788 | int | |
4682ae04 | 1789 | read_dependence (rtx mem, rtx x) |
9ae8ffe7 JL |
1790 | { |
1791 | return MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem); | |
1792 | } | |
1793 | ||
c6df88cb MM |
1794 | /* Returns MEM1 if and only if MEM1 is a scalar at a fixed address and |
1795 | MEM2 is a reference to a structure at a varying address, or returns | |
1796 | MEM2 if vice versa. Otherwise, returns NULL_RTX. If a non-NULL | |
1797 | value is returned MEM1 and MEM2 can never alias. VARIES_P is used | |
1798 | to decide whether or not an address may vary; it should return | |
eab5c70a BS |
1799 | nonzero whenever variation is possible. |
1800 | MEM1_ADDR and MEM2_ADDR are the addresses of MEM1 and MEM2. */ | |
ca7fd9cd | 1801 | |
2c72b78f | 1802 | static rtx |
4682ae04 AJ |
1803 | fixed_scalar_and_varying_struct_p (rtx mem1, rtx mem2, rtx mem1_addr, |
1804 | rtx mem2_addr, | |
1805 | int (*varies_p) (rtx, int)) | |
ca7fd9cd | 1806 | { |
3e0abe15 GK |
1807 | if (! flag_strict_aliasing) |
1808 | return NULL_RTX; | |
1809 | ||
ca7fd9cd | 1810 | if (MEM_SCALAR_P (mem1) && MEM_IN_STRUCT_P (mem2) |
e38fe8e0 | 1811 | && !varies_p (mem1_addr, 1) && varies_p (mem2_addr, 1)) |
c6df88cb MM |
1812 | /* MEM1 is a scalar at a fixed address; MEM2 is a struct at a |
1813 | varying address. */ | |
1814 | return mem1; | |
1815 | ||
ca7fd9cd | 1816 | if (MEM_IN_STRUCT_P (mem1) && MEM_SCALAR_P (mem2) |
e38fe8e0 | 1817 | && varies_p (mem1_addr, 1) && !varies_p (mem2_addr, 1)) |
c6df88cb MM |
1818 | /* MEM2 is a scalar at a fixed address; MEM1 is a struct at a |
1819 | varying address. */ | |
1820 | return mem2; | |
1821 | ||
1822 | return NULL_RTX; | |
1823 | } | |
1824 | ||
1825 | /* Returns nonzero if something about the mode or address format MEM1 | |
1826 | indicates that it might well alias *anything*. */ | |
1827 | ||
2c72b78f | 1828 | static int |
4682ae04 | 1829 | aliases_everything_p (rtx mem) |
c6df88cb | 1830 | { |
c6df88cb MM |
1831 | if (GET_CODE (XEXP (mem, 0)) == AND) |
1832 | /* If the address is an AND, its very hard to know at what it is | |
1833 | actually pointing. */ | |
1834 | return 1; | |
ca7fd9cd | 1835 | |
c6df88cb MM |
1836 | return 0; |
1837 | } | |
1838 | ||
998d7deb RH |
1839 | /* Return true if we can determine that the fields referenced cannot |
1840 | overlap for any pair of objects. */ | |
1841 | ||
1842 | static bool | |
4682ae04 | 1843 | nonoverlapping_component_refs_p (tree x, tree y) |
998d7deb RH |
1844 | { |
1845 | tree fieldx, fieldy, typex, typey, orig_y; | |
1846 | ||
1847 | do | |
1848 | { | |
1849 | /* The comparison has to be done at a common type, since we don't | |
d6a7951f | 1850 | know how the inheritance hierarchy works. */ |
998d7deb RH |
1851 | orig_y = y; |
1852 | do | |
1853 | { | |
1854 | fieldx = TREE_OPERAND (x, 1); | |
1855 | typex = DECL_FIELD_CONTEXT (fieldx); | |
1856 | ||
1857 | y = orig_y; | |
1858 | do | |
1859 | { | |
1860 | fieldy = TREE_OPERAND (y, 1); | |
1861 | typey = DECL_FIELD_CONTEXT (fieldy); | |
1862 | ||
1863 | if (typex == typey) | |
1864 | goto found; | |
1865 | ||
1866 | y = TREE_OPERAND (y, 0); | |
1867 | } | |
1868 | while (y && TREE_CODE (y) == COMPONENT_REF); | |
1869 | ||
1870 | x = TREE_OPERAND (x, 0); | |
1871 | } | |
1872 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
1873 | ||
1874 | /* Never found a common type. */ | |
1875 | return false; | |
1876 | ||
1877 | found: | |
1878 | /* If we're left with accessing different fields of a structure, | |
1879 | then no overlap. */ | |
1880 | if (TREE_CODE (typex) == RECORD_TYPE | |
1881 | && fieldx != fieldy) | |
1882 | return true; | |
1883 | ||
1884 | /* The comparison on the current field failed. If we're accessing | |
1885 | a very nested structure, look at the next outer level. */ | |
1886 | x = TREE_OPERAND (x, 0); | |
1887 | y = TREE_OPERAND (y, 0); | |
1888 | } | |
1889 | while (x && y | |
1890 | && TREE_CODE (x) == COMPONENT_REF | |
1891 | && TREE_CODE (y) == COMPONENT_REF); | |
ca7fd9cd | 1892 | |
998d7deb RH |
1893 | return false; |
1894 | } | |
1895 | ||
1896 | /* Look at the bottom of the COMPONENT_REF list for a DECL, and return it. */ | |
1897 | ||
1898 | static tree | |
4682ae04 | 1899 | decl_for_component_ref (tree x) |
998d7deb RH |
1900 | { |
1901 | do | |
1902 | { | |
1903 | x = TREE_OPERAND (x, 0); | |
1904 | } | |
1905 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
1906 | ||
1907 | return x && DECL_P (x) ? x : NULL_TREE; | |
1908 | } | |
1909 | ||
1910 | /* Walk up the COMPONENT_REF list and adjust OFFSET to compensate for the | |
1911 | offset of the field reference. */ | |
1912 | ||
1913 | static rtx | |
4682ae04 | 1914 | adjust_offset_for_component_ref (tree x, rtx offset) |
998d7deb RH |
1915 | { |
1916 | HOST_WIDE_INT ioffset; | |
1917 | ||
1918 | if (! offset) | |
1919 | return NULL_RTX; | |
1920 | ||
1921 | ioffset = INTVAL (offset); | |
ca7fd9cd | 1922 | do |
998d7deb RH |
1923 | { |
1924 | tree field = TREE_OPERAND (x, 1); | |
1925 | ||
1926 | if (! host_integerp (DECL_FIELD_OFFSET (field), 1)) | |
1927 | return NULL_RTX; | |
1928 | ioffset += (tree_low_cst (DECL_FIELD_OFFSET (field), 1) | |
1929 | + (tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1) | |
1930 | / BITS_PER_UNIT)); | |
1931 | ||
1932 | x = TREE_OPERAND (x, 0); | |
1933 | } | |
1934 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
1935 | ||
1936 | return GEN_INT (ioffset); | |
1937 | } | |
1938 | ||
95bd1dd7 | 1939 | /* Return nonzero if we can determine the exprs corresponding to memrefs |
a4311dfe RK |
1940 | X and Y and they do not overlap. */ |
1941 | ||
1942 | static int | |
4682ae04 | 1943 | nonoverlapping_memrefs_p (rtx x, rtx y) |
a4311dfe | 1944 | { |
998d7deb | 1945 | tree exprx = MEM_EXPR (x), expry = MEM_EXPR (y); |
a4311dfe RK |
1946 | rtx rtlx, rtly; |
1947 | rtx basex, basey; | |
998d7deb | 1948 | rtx moffsetx, moffsety; |
a4311dfe RK |
1949 | HOST_WIDE_INT offsetx = 0, offsety = 0, sizex, sizey, tem; |
1950 | ||
998d7deb RH |
1951 | /* Unless both have exprs, we can't tell anything. */ |
1952 | if (exprx == 0 || expry == 0) | |
1953 | return 0; | |
1954 | ||
1955 | /* If both are field references, we may be able to determine something. */ | |
1956 | if (TREE_CODE (exprx) == COMPONENT_REF | |
1957 | && TREE_CODE (expry) == COMPONENT_REF | |
1958 | && nonoverlapping_component_refs_p (exprx, expry)) | |
1959 | return 1; | |
1960 | ||
1961 | /* If the field reference test failed, look at the DECLs involved. */ | |
1962 | moffsetx = MEM_OFFSET (x); | |
1963 | if (TREE_CODE (exprx) == COMPONENT_REF) | |
1964 | { | |
1965 | tree t = decl_for_component_ref (exprx); | |
1966 | if (! t) | |
1967 | return 0; | |
1968 | moffsetx = adjust_offset_for_component_ref (exprx, moffsetx); | |
1969 | exprx = t; | |
1970 | } | |
c67a1cf6 RH |
1971 | else if (TREE_CODE (exprx) == INDIRECT_REF) |
1972 | { | |
1973 | exprx = TREE_OPERAND (exprx, 0); | |
1974 | if (flag_argument_noalias < 2 | |
1975 | || TREE_CODE (exprx) != PARM_DECL) | |
1976 | return 0; | |
1977 | } | |
1978 | ||
998d7deb RH |
1979 | moffsety = MEM_OFFSET (y); |
1980 | if (TREE_CODE (expry) == COMPONENT_REF) | |
1981 | { | |
1982 | tree t = decl_for_component_ref (expry); | |
1983 | if (! t) | |
1984 | return 0; | |
1985 | moffsety = adjust_offset_for_component_ref (expry, moffsety); | |
1986 | expry = t; | |
1987 | } | |
c67a1cf6 RH |
1988 | else if (TREE_CODE (expry) == INDIRECT_REF) |
1989 | { | |
1990 | expry = TREE_OPERAND (expry, 0); | |
1991 | if (flag_argument_noalias < 2 | |
1992 | || TREE_CODE (expry) != PARM_DECL) | |
1993 | return 0; | |
1994 | } | |
998d7deb RH |
1995 | |
1996 | if (! DECL_P (exprx) || ! DECL_P (expry)) | |
a4311dfe RK |
1997 | return 0; |
1998 | ||
998d7deb RH |
1999 | rtlx = DECL_RTL (exprx); |
2000 | rtly = DECL_RTL (expry); | |
a4311dfe | 2001 | |
1edcd60b RK |
2002 | /* If either RTL is not a MEM, it must be a REG or CONCAT, meaning they |
2003 | can't overlap unless they are the same because we never reuse that part | |
2004 | of the stack frame used for locals for spilled pseudos. */ | |
2005 | if ((GET_CODE (rtlx) != MEM || GET_CODE (rtly) != MEM) | |
2006 | && ! rtx_equal_p (rtlx, rtly)) | |
a4311dfe RK |
2007 | return 1; |
2008 | ||
2009 | /* Get the base and offsets of both decls. If either is a register, we | |
2010 | know both are and are the same, so use that as the base. The only | |
2011 | we can avoid overlap is if we can deduce that they are nonoverlapping | |
2012 | pieces of that decl, which is very rare. */ | |
1edcd60b | 2013 | basex = GET_CODE (rtlx) == MEM ? XEXP (rtlx, 0) : rtlx; |
a4311dfe RK |
2014 | if (GET_CODE (basex) == PLUS && GET_CODE (XEXP (basex, 1)) == CONST_INT) |
2015 | offsetx = INTVAL (XEXP (basex, 1)), basex = XEXP (basex, 0); | |
2016 | ||
1edcd60b | 2017 | basey = GET_CODE (rtly) == MEM ? XEXP (rtly, 0) : rtly; |
a4311dfe RK |
2018 | if (GET_CODE (basey) == PLUS && GET_CODE (XEXP (basey, 1)) == CONST_INT) |
2019 | offsety = INTVAL (XEXP (basey, 1)), basey = XEXP (basey, 0); | |
2020 | ||
d746694a | 2021 | /* If the bases are different, we know they do not overlap if both |
ca7fd9cd | 2022 | are constants or if one is a constant and the other a pointer into the |
d746694a RK |
2023 | stack frame. Otherwise a different base means we can't tell if they |
2024 | overlap or not. */ | |
2025 | if (! rtx_equal_p (basex, basey)) | |
ca7fd9cd KH |
2026 | return ((CONSTANT_P (basex) && CONSTANT_P (basey)) |
2027 | || (CONSTANT_P (basex) && REG_P (basey) | |
2028 | && REGNO_PTR_FRAME_P (REGNO (basey))) | |
2029 | || (CONSTANT_P (basey) && REG_P (basex) | |
2030 | && REGNO_PTR_FRAME_P (REGNO (basex)))); | |
a4311dfe | 2031 | |
998d7deb | 2032 | sizex = (GET_CODE (rtlx) != MEM ? (int) GET_MODE_SIZE (GET_MODE (rtlx)) |
a4311dfe RK |
2033 | : MEM_SIZE (rtlx) ? INTVAL (MEM_SIZE (rtlx)) |
2034 | : -1); | |
998d7deb | 2035 | sizey = (GET_CODE (rtly) != MEM ? (int) GET_MODE_SIZE (GET_MODE (rtly)) |
a4311dfe RK |
2036 | : MEM_SIZE (rtly) ? INTVAL (MEM_SIZE (rtly)) : |
2037 | -1); | |
2038 | ||
0af5bc3e RK |
2039 | /* If we have an offset for either memref, it can update the values computed |
2040 | above. */ | |
998d7deb RH |
2041 | if (moffsetx) |
2042 | offsetx += INTVAL (moffsetx), sizex -= INTVAL (moffsetx); | |
2043 | if (moffsety) | |
2044 | offsety += INTVAL (moffsety), sizey -= INTVAL (moffsety); | |
a4311dfe | 2045 | |
0af5bc3e | 2046 | /* If a memref has both a size and an offset, we can use the smaller size. |
efc981bb | 2047 | We can't do this if the offset isn't known because we must view this |
0af5bc3e | 2048 | memref as being anywhere inside the DECL's MEM. */ |
998d7deb | 2049 | if (MEM_SIZE (x) && moffsetx) |
a4311dfe | 2050 | sizex = INTVAL (MEM_SIZE (x)); |
998d7deb | 2051 | if (MEM_SIZE (y) && moffsety) |
a4311dfe RK |
2052 | sizey = INTVAL (MEM_SIZE (y)); |
2053 | ||
2054 | /* Put the values of the memref with the lower offset in X's values. */ | |
2055 | if (offsetx > offsety) | |
2056 | { | |
2057 | tem = offsetx, offsetx = offsety, offsety = tem; | |
2058 | tem = sizex, sizex = sizey, sizey = tem; | |
2059 | } | |
2060 | ||
2061 | /* If we don't know the size of the lower-offset value, we can't tell | |
2062 | if they conflict. Otherwise, we do the test. */ | |
a6f7c915 | 2063 | return sizex >= 0 && offsety >= offsetx + sizex; |
a4311dfe RK |
2064 | } |
2065 | ||
9ae8ffe7 JL |
2066 | /* True dependence: X is read after store in MEM takes place. */ |
2067 | ||
2068 | int | |
4682ae04 AJ |
2069 | true_dependence (rtx mem, enum machine_mode mem_mode, rtx x, |
2070 | int (*varies) (rtx, int)) | |
9ae8ffe7 | 2071 | { |
b3694847 | 2072 | rtx x_addr, mem_addr; |
49982682 | 2073 | rtx base; |
9ae8ffe7 JL |
2074 | |
2075 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) | |
2076 | return 1; | |
2077 | ||
c4484b8f RH |
2078 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
2079 | This is used in epilogue deallocation functions. */ | |
2080 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) | |
2081 | return 1; | |
2082 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
2083 | return 1; | |
2084 | ||
41472af8 MM |
2085 | if (DIFFERENT_ALIAS_SETS_P (x, mem)) |
2086 | return 0; | |
2087 | ||
b949ea8b JW |
2088 | /* Unchanging memory can't conflict with non-unchanging memory. |
2089 | A non-unchanging read can conflict with a non-unchanging write. | |
2090 | An unchanging read can conflict with an unchanging write since | |
2091 | there may be a single store to this address to initialize it. | |
ec569656 RK |
2092 | Note that an unchanging store can conflict with a non-unchanging read |
2093 | since we have to make conservative assumptions when we have a | |
2094 | record with readonly fields and we are copying the whole thing. | |
b949ea8b JW |
2095 | Just fall through to the code below to resolve potential conflicts. |
2096 | This won't handle all cases optimally, but the possible performance | |
2097 | loss should be negligible. */ | |
ec569656 | 2098 | if (RTX_UNCHANGING_P (x) && ! RTX_UNCHANGING_P (mem)) |
9ae8ffe7 JL |
2099 | return 0; |
2100 | ||
a4311dfe RK |
2101 | if (nonoverlapping_memrefs_p (mem, x)) |
2102 | return 0; | |
2103 | ||
56ee9281 RH |
2104 | if (mem_mode == VOIDmode) |
2105 | mem_mode = GET_MODE (mem); | |
2106 | ||
eab5c70a BS |
2107 | x_addr = get_addr (XEXP (x, 0)); |
2108 | mem_addr = get_addr (XEXP (mem, 0)); | |
2109 | ||
55efb413 JW |
2110 | base = find_base_term (x_addr); |
2111 | if (base && (GET_CODE (base) == LABEL_REF | |
2112 | || (GET_CODE (base) == SYMBOL_REF | |
2113 | && CONSTANT_POOL_ADDRESS_P (base)))) | |
2114 | return 0; | |
2115 | ||
eab5c70a | 2116 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), mem_mode)) |
1c72c7f6 JC |
2117 | return 0; |
2118 | ||
eab5c70a BS |
2119 | x_addr = canon_rtx (x_addr); |
2120 | mem_addr = canon_rtx (mem_addr); | |
6e73e666 | 2121 | |
0211b6ab JW |
2122 | if (! memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr, |
2123 | SIZE_FOR_MODE (x), x_addr, 0)) | |
2124 | return 0; | |
2125 | ||
c6df88cb | 2126 | if (aliases_everything_p (x)) |
0211b6ab JW |
2127 | return 1; |
2128 | ||
f5143c46 | 2129 | /* We cannot use aliases_everything_p to test MEM, since we must look |
c6df88cb MM |
2130 | at MEM_MODE, rather than GET_MODE (MEM). */ |
2131 | if (mem_mode == QImode || GET_CODE (mem_addr) == AND) | |
a13d4ebf AM |
2132 | return 1; |
2133 | ||
2134 | /* In true_dependence we also allow BLKmode to alias anything. Why | |
2135 | don't we do this in anti_dependence and output_dependence? */ | |
2136 | if (mem_mode == BLKmode || GET_MODE (x) == BLKmode) | |
2137 | return 1; | |
2138 | ||
2139 | return ! fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, | |
2140 | varies); | |
2141 | } | |
2142 | ||
2143 | /* Canonical true dependence: X is read after store in MEM takes place. | |
ca7fd9cd KH |
2144 | Variant of true_dependence which assumes MEM has already been |
2145 | canonicalized (hence we no longer do that here). | |
2146 | The mem_addr argument has been added, since true_dependence computed | |
a13d4ebf AM |
2147 | this value prior to canonicalizing. */ |
2148 | ||
2149 | int | |
4682ae04 AJ |
2150 | canon_true_dependence (rtx mem, enum machine_mode mem_mode, rtx mem_addr, |
2151 | rtx x, int (*varies) (rtx, int)) | |
a13d4ebf | 2152 | { |
b3694847 | 2153 | rtx x_addr; |
a13d4ebf AM |
2154 | |
2155 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) | |
2156 | return 1; | |
2157 | ||
0fe854a7 RH |
2158 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
2159 | This is used in epilogue deallocation functions. */ | |
2160 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) | |
2161 | return 1; | |
2162 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
2163 | return 1; | |
2164 | ||
a13d4ebf AM |
2165 | if (DIFFERENT_ALIAS_SETS_P (x, mem)) |
2166 | return 0; | |
2167 | ||
2168 | /* If X is an unchanging read, then it can't possibly conflict with any | |
2169 | non-unchanging store. It may conflict with an unchanging write though, | |
2170 | because there may be a single store to this address to initialize it. | |
2171 | Just fall through to the code below to resolve the case where we have | |
2172 | both an unchanging read and an unchanging write. This won't handle all | |
2173 | cases optimally, but the possible performance loss should be | |
2174 | negligible. */ | |
2175 | if (RTX_UNCHANGING_P (x) && ! RTX_UNCHANGING_P (mem)) | |
2176 | return 0; | |
2177 | ||
a4311dfe RK |
2178 | if (nonoverlapping_memrefs_p (x, mem)) |
2179 | return 0; | |
2180 | ||
a13d4ebf AM |
2181 | x_addr = get_addr (XEXP (x, 0)); |
2182 | ||
2183 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), mem_mode)) | |
2184 | return 0; | |
2185 | ||
2186 | x_addr = canon_rtx (x_addr); | |
2187 | if (! memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr, | |
2188 | SIZE_FOR_MODE (x), x_addr, 0)) | |
2189 | return 0; | |
2190 | ||
2191 | if (aliases_everything_p (x)) | |
2192 | return 1; | |
2193 | ||
f5143c46 | 2194 | /* We cannot use aliases_everything_p to test MEM, since we must look |
a13d4ebf AM |
2195 | at MEM_MODE, rather than GET_MODE (MEM). */ |
2196 | if (mem_mode == QImode || GET_CODE (mem_addr) == AND) | |
c6df88cb | 2197 | return 1; |
0211b6ab | 2198 | |
c6df88cb MM |
2199 | /* In true_dependence we also allow BLKmode to alias anything. Why |
2200 | don't we do this in anti_dependence and output_dependence? */ | |
2201 | if (mem_mode == BLKmode || GET_MODE (x) == BLKmode) | |
2202 | return 1; | |
0211b6ab | 2203 | |
eab5c70a BS |
2204 | return ! fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, |
2205 | varies); | |
9ae8ffe7 JL |
2206 | } |
2207 | ||
da7d8304 | 2208 | /* Returns nonzero if a write to X might alias a previous read from |
83a00410 | 2209 | (or, if WRITEP is nonzero, a write to) MEM. If CONSTP is nonzero, |
d2399d75 | 2210 | honor the RTX_UNCHANGING_P flags on X and MEM. */ |
9ae8ffe7 | 2211 | |
2c72b78f | 2212 | static int |
d2399d75 | 2213 | write_dependence_p (rtx mem, rtx x, int writep, int constp) |
9ae8ffe7 | 2214 | { |
6e73e666 | 2215 | rtx x_addr, mem_addr; |
c6df88cb | 2216 | rtx fixed_scalar; |
49982682 | 2217 | rtx base; |
6e73e666 | 2218 | |
9ae8ffe7 JL |
2219 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) |
2220 | return 1; | |
2221 | ||
c4484b8f RH |
2222 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
2223 | This is used in epilogue deallocation functions. */ | |
2224 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) | |
2225 | return 1; | |
2226 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
2227 | return 1; | |
2228 | ||
eab5c70a BS |
2229 | if (DIFFERENT_ALIAS_SETS_P (x, mem)) |
2230 | return 0; | |
2231 | ||
d2399d75 RS |
2232 | if (constp) |
2233 | { | |
2234 | /* Unchanging memory can't conflict with non-unchanging memory. */ | |
2235 | if (RTX_UNCHANGING_P (x) != RTX_UNCHANGING_P (mem)) | |
2236 | return 0; | |
b949ea8b | 2237 | |
d2399d75 RS |
2238 | /* If MEM is an unchanging read, then it can't possibly conflict with |
2239 | the store to X, because there is at most one store to MEM, and it | |
2240 | must have occurred somewhere before MEM. */ | |
2241 | if (! writep && RTX_UNCHANGING_P (mem)) | |
2242 | return 0; | |
2243 | } | |
55efb413 | 2244 | |
a4311dfe RK |
2245 | if (nonoverlapping_memrefs_p (x, mem)) |
2246 | return 0; | |
2247 | ||
55efb413 JW |
2248 | x_addr = get_addr (XEXP (x, 0)); |
2249 | mem_addr = get_addr (XEXP (mem, 0)); | |
2250 | ||
49982682 JW |
2251 | if (! writep) |
2252 | { | |
55efb413 | 2253 | base = find_base_term (mem_addr); |
49982682 JW |
2254 | if (base && (GET_CODE (base) == LABEL_REF |
2255 | || (GET_CODE (base) == SYMBOL_REF | |
2256 | && CONSTANT_POOL_ADDRESS_P (base)))) | |
2257 | return 0; | |
2258 | } | |
2259 | ||
eab5c70a BS |
2260 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), |
2261 | GET_MODE (mem))) | |
41472af8 MM |
2262 | return 0; |
2263 | ||
eab5c70a BS |
2264 | x_addr = canon_rtx (x_addr); |
2265 | mem_addr = canon_rtx (mem_addr); | |
6e73e666 | 2266 | |
c6df88cb MM |
2267 | if (!memrefs_conflict_p (SIZE_FOR_MODE (mem), mem_addr, |
2268 | SIZE_FOR_MODE (x), x_addr, 0)) | |
2269 | return 0; | |
2270 | ||
ca7fd9cd | 2271 | fixed_scalar |
eab5c70a BS |
2272 | = fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, |
2273 | rtx_addr_varies_p); | |
2274 | ||
c6df88cb MM |
2275 | return (!(fixed_scalar == mem && !aliases_everything_p (x)) |
2276 | && !(fixed_scalar == x && !aliases_everything_p (mem))); | |
2277 | } | |
2278 | ||
2279 | /* Anti dependence: X is written after read in MEM takes place. */ | |
2280 | ||
2281 | int | |
4682ae04 | 2282 | anti_dependence (rtx mem, rtx x) |
c6df88cb | 2283 | { |
d2399d75 | 2284 | return write_dependence_p (mem, x, /*writep=*/0, /*constp*/1); |
9ae8ffe7 JL |
2285 | } |
2286 | ||
2287 | /* Output dependence: X is written after store in MEM takes place. */ | |
2288 | ||
2289 | int | |
4682ae04 | 2290 | output_dependence (rtx mem, rtx x) |
9ae8ffe7 | 2291 | { |
d2399d75 RS |
2292 | return write_dependence_p (mem, x, /*writep=*/1, /*constp*/1); |
2293 | } | |
2294 | ||
2295 | /* Unchanging anti dependence: Like anti_dependence but ignores | |
2296 | the UNCHANGING_RTX_P property on const variable references. */ | |
2297 | ||
2298 | int | |
2299 | unchanging_anti_dependence (rtx mem, rtx x) | |
2300 | { | |
2301 | return write_dependence_p (mem, x, /*writep=*/0, /*constp*/0); | |
9ae8ffe7 | 2302 | } |
c14b9960 JW |
2303 | \f |
2304 | /* A subroutine of nonlocal_mentioned_p, returns 1 if *LOC mentions | |
2305 | something which is not local to the function and is not constant. */ | |
7790df19 JW |
2306 | |
2307 | static int | |
4682ae04 | 2308 | nonlocal_mentioned_p_1 (rtx *loc, void *data ATTRIBUTE_UNUSED) |
7790df19 | 2309 | { |
c14b9960 | 2310 | rtx x = *loc; |
7790df19 | 2311 | rtx base; |
7790df19 JW |
2312 | int regno; |
2313 | ||
c14b9960 JW |
2314 | if (! x) |
2315 | return 0; | |
7790df19 | 2316 | |
c14b9960 | 2317 | switch (GET_CODE (x)) |
7790df19 JW |
2318 | { |
2319 | case SUBREG: | |
2320 | if (GET_CODE (SUBREG_REG (x)) == REG) | |
2321 | { | |
2322 | /* Global registers are not local. */ | |
2323 | if (REGNO (SUBREG_REG (x)) < FIRST_PSEUDO_REGISTER | |
ddef6bc7 | 2324 | && global_regs[subreg_regno (x)]) |
7790df19 JW |
2325 | return 1; |
2326 | return 0; | |
2327 | } | |
2328 | break; | |
2329 | ||
2330 | case REG: | |
2331 | regno = REGNO (x); | |
2332 | /* Global registers are not local. */ | |
2333 | if (regno < FIRST_PSEUDO_REGISTER && global_regs[regno]) | |
2334 | return 1; | |
2335 | return 0; | |
2336 | ||
2337 | case SCRATCH: | |
2338 | case PC: | |
2339 | case CC0: | |
2340 | case CONST_INT: | |
2341 | case CONST_DOUBLE: | |
69ef87e2 | 2342 | case CONST_VECTOR: |
7790df19 JW |
2343 | case CONST: |
2344 | case LABEL_REF: | |
2345 | return 0; | |
2346 | ||
2347 | case SYMBOL_REF: | |
2348 | /* Constants in the function's constants pool are constant. */ | |
2349 | if (CONSTANT_POOL_ADDRESS_P (x)) | |
2350 | return 0; | |
2351 | return 1; | |
2352 | ||
2353 | case CALL: | |
bf6d9fd7 | 2354 | /* Non-constant calls and recursion are not local. */ |
7790df19 JW |
2355 | return 1; |
2356 | ||
2357 | case MEM: | |
2358 | /* Be overly conservative and consider any volatile memory | |
2359 | reference as not local. */ | |
2360 | if (MEM_VOLATILE_P (x)) | |
2361 | return 1; | |
2362 | base = find_base_term (XEXP (x, 0)); | |
2363 | if (base) | |
2364 | { | |
b3b5ad95 JL |
2365 | /* A Pmode ADDRESS could be a reference via the structure value |
2366 | address or static chain. Such memory references are nonlocal. | |
2367 | ||
2368 | Thus, we have to examine the contents of the ADDRESS to find | |
2369 | out if this is a local reference or not. */ | |
2370 | if (GET_CODE (base) == ADDRESS | |
2371 | && GET_MODE (base) == Pmode | |
2372 | && (XEXP (base, 0) == stack_pointer_rtx | |
2373 | || XEXP (base, 0) == arg_pointer_rtx | |
2374 | #if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM | |
2375 | || XEXP (base, 0) == hard_frame_pointer_rtx | |
2376 | #endif | |
2377 | || XEXP (base, 0) == frame_pointer_rtx)) | |
7790df19 JW |
2378 | return 0; |
2379 | /* Constants in the function's constant pool are constant. */ | |
2380 | if (GET_CODE (base) == SYMBOL_REF && CONSTANT_POOL_ADDRESS_P (base)) | |
2381 | return 0; | |
2382 | } | |
2383 | return 1; | |
2384 | ||
bf6d9fd7 | 2385 | case UNSPEC_VOLATILE: |
7790df19 | 2386 | case ASM_INPUT: |
7790df19 JW |
2387 | return 1; |
2388 | ||
bf6d9fd7 JW |
2389 | case ASM_OPERANDS: |
2390 | if (MEM_VOLATILE_P (x)) | |
2391 | return 1; | |
2392 | ||
5d3cc252 | 2393 | /* Fall through. */ |
bf6d9fd7 | 2394 | |
7790df19 JW |
2395 | default: |
2396 | break; | |
2397 | } | |
2398 | ||
c14b9960 JW |
2399 | return 0; |
2400 | } | |
2401 | ||
da7d8304 | 2402 | /* Returns nonzero if X might mention something which is not |
c14b9960 | 2403 | local to the function and is not constant. */ |
7790df19 | 2404 | |
c14b9960 | 2405 | static int |
4682ae04 | 2406 | nonlocal_mentioned_p (rtx x) |
c14b9960 | 2407 | { |
c14b9960 JW |
2408 | if (INSN_P (x)) |
2409 | { | |
2410 | if (GET_CODE (x) == CALL_INSN) | |
2411 | { | |
2412 | if (! CONST_OR_PURE_CALL_P (x)) | |
2413 | return 1; | |
2414 | x = CALL_INSN_FUNCTION_USAGE (x); | |
2415 | if (x == 0) | |
2416 | return 0; | |
ca7fd9cd | 2417 | } |
c14b9960 | 2418 | else |
ca7fd9cd | 2419 | x = PATTERN (x); |
c14b9960 JW |
2420 | } |
2421 | ||
2422 | return for_each_rtx (&x, nonlocal_mentioned_p_1, NULL); | |
2423 | } | |
2424 | ||
2425 | /* A subroutine of nonlocal_referenced_p, returns 1 if *LOC references | |
2426 | something which is not local to the function and is not constant. */ | |
2427 | ||
2428 | static int | |
4682ae04 | 2429 | nonlocal_referenced_p_1 (rtx *loc, void *data ATTRIBUTE_UNUSED) |
c14b9960 JW |
2430 | { |
2431 | rtx x = *loc; | |
2432 | ||
2433 | if (! x) | |
2434 | return 0; | |
2435 | ||
2436 | switch (GET_CODE (x)) | |
2437 | { | |
2438 | case MEM: | |
2439 | case REG: | |
2440 | case SYMBOL_REF: | |
2441 | case SUBREG: | |
2442 | return nonlocal_mentioned_p (x); | |
2443 | ||
2444 | case CALL: | |
2445 | /* Non-constant calls and recursion are not local. */ | |
2446 | return 1; | |
2447 | ||
2448 | case SET: | |
2449 | if (nonlocal_mentioned_p (SET_SRC (x))) | |
2450 | return 1; | |
2451 | ||
2452 | if (GET_CODE (SET_DEST (x)) == MEM) | |
2453 | return nonlocal_mentioned_p (XEXP (SET_DEST (x), 0)); | |
2454 | ||
2455 | /* If the destination is anything other than a CC0, PC, | |
2456 | MEM, REG, or a SUBREG of a REG that occupies all of | |
2457 | the REG, then X references nonlocal memory if it is | |
2458 | mentioned in the destination. */ | |
2459 | if (GET_CODE (SET_DEST (x)) != CC0 | |
2460 | && GET_CODE (SET_DEST (x)) != PC | |
2461 | && GET_CODE (SET_DEST (x)) != REG | |
2462 | && ! (GET_CODE (SET_DEST (x)) == SUBREG | |
2463 | && GET_CODE (SUBREG_REG (SET_DEST (x))) == REG | |
2464 | && (((GET_MODE_SIZE (GET_MODE (SUBREG_REG (SET_DEST (x)))) | |
2465 | + (UNITS_PER_WORD - 1)) / UNITS_PER_WORD) | |
2466 | == ((GET_MODE_SIZE (GET_MODE (SET_DEST (x))) | |
2467 | + (UNITS_PER_WORD - 1)) / UNITS_PER_WORD)))) | |
2468 | return nonlocal_mentioned_p (SET_DEST (x)); | |
2469 | return 0; | |
2470 | ||
2471 | case CLOBBER: | |
2472 | if (GET_CODE (XEXP (x, 0)) == MEM) | |
2473 | return nonlocal_mentioned_p (XEXP (XEXP (x, 0), 0)); | |
2474 | return 0; | |
2475 | ||
2476 | case USE: | |
2477 | return nonlocal_mentioned_p (XEXP (x, 0)); | |
2478 | ||
2479 | case ASM_INPUT: | |
2480 | case UNSPEC_VOLATILE: | |
2481 | return 1; | |
2482 | ||
2483 | case ASM_OPERANDS: | |
2484 | if (MEM_VOLATILE_P (x)) | |
2485 | return 1; | |
2486 | ||
5d3cc252 | 2487 | /* Fall through. */ |
c14b9960 JW |
2488 | |
2489 | default: | |
2490 | break; | |
2491 | } | |
2492 | ||
2493 | return 0; | |
2494 | } | |
2495 | ||
da7d8304 | 2496 | /* Returns nonzero if X might reference something which is not |
c14b9960 JW |
2497 | local to the function and is not constant. */ |
2498 | ||
2499 | static int | |
4682ae04 | 2500 | nonlocal_referenced_p (rtx x) |
c14b9960 | 2501 | { |
c14b9960 JW |
2502 | if (INSN_P (x)) |
2503 | { | |
2504 | if (GET_CODE (x) == CALL_INSN) | |
2505 | { | |
2506 | if (! CONST_OR_PURE_CALL_P (x)) | |
2507 | return 1; | |
2508 | x = CALL_INSN_FUNCTION_USAGE (x); | |
2509 | if (x == 0) | |
2510 | return 0; | |
ca7fd9cd | 2511 | } |
c14b9960 | 2512 | else |
ca7fd9cd | 2513 | x = PATTERN (x); |
c14b9960 JW |
2514 | } |
2515 | ||
2516 | return for_each_rtx (&x, nonlocal_referenced_p_1, NULL); | |
2517 | } | |
2518 | ||
2519 | /* A subroutine of nonlocal_set_p, returns 1 if *LOC sets | |
2520 | something which is not local to the function and is not constant. */ | |
2521 | ||
2522 | static int | |
4682ae04 | 2523 | nonlocal_set_p_1 (rtx *loc, void *data ATTRIBUTE_UNUSED) |
c14b9960 JW |
2524 | { |
2525 | rtx x = *loc; | |
2526 | ||
2527 | if (! x) | |
2528 | return 0; | |
2529 | ||
2530 | switch (GET_CODE (x)) | |
2531 | { | |
2532 | case CALL: | |
2533 | /* Non-constant calls and recursion are not local. */ | |
2534 | return 1; | |
2535 | ||
2536 | case PRE_INC: | |
2537 | case PRE_DEC: | |
2538 | case POST_INC: | |
2539 | case POST_DEC: | |
2540 | case PRE_MODIFY: | |
2541 | case POST_MODIFY: | |
2542 | return nonlocal_mentioned_p (XEXP (x, 0)); | |
2543 | ||
2544 | case SET: | |
2545 | if (nonlocal_mentioned_p (SET_DEST (x))) | |
2546 | return 1; | |
2547 | return nonlocal_set_p (SET_SRC (x)); | |
2548 | ||
2549 | case CLOBBER: | |
2550 | return nonlocal_mentioned_p (XEXP (x, 0)); | |
2551 | ||
2552 | case USE: | |
2553 | return 0; | |
2554 | ||
2555 | case ASM_INPUT: | |
2556 | case UNSPEC_VOLATILE: | |
2557 | return 1; | |
2558 | ||
2559 | case ASM_OPERANDS: | |
2560 | if (MEM_VOLATILE_P (x)) | |
2561 | return 1; | |
2562 | ||
5d3cc252 | 2563 | /* Fall through. */ |
c14b9960 JW |
2564 | |
2565 | default: | |
2566 | break; | |
2567 | } | |
7790df19 JW |
2568 | |
2569 | return 0; | |
2570 | } | |
2571 | ||
da7d8304 | 2572 | /* Returns nonzero if X might set something which is not |
c14b9960 JW |
2573 | local to the function and is not constant. */ |
2574 | ||
2575 | static int | |
4682ae04 | 2576 | nonlocal_set_p (rtx x) |
c14b9960 | 2577 | { |
c14b9960 JW |
2578 | if (INSN_P (x)) |
2579 | { | |
2580 | if (GET_CODE (x) == CALL_INSN) | |
2581 | { | |
2582 | if (! CONST_OR_PURE_CALL_P (x)) | |
2583 | return 1; | |
2584 | x = CALL_INSN_FUNCTION_USAGE (x); | |
2585 | if (x == 0) | |
2586 | return 0; | |
ca7fd9cd | 2587 | } |
c14b9960 | 2588 | else |
ca7fd9cd | 2589 | x = PATTERN (x); |
c14b9960 JW |
2590 | } |
2591 | ||
2592 | return for_each_rtx (&x, nonlocal_set_p_1, NULL); | |
2593 | } | |
2594 | ||
c57ddcf1 | 2595 | /* Mark the function if it is pure or constant. */ |
7790df19 JW |
2596 | |
2597 | void | |
4682ae04 | 2598 | mark_constant_function (void) |
7790df19 JW |
2599 | { |
2600 | rtx insn; | |
c14b9960 | 2601 | int nonlocal_memory_referenced; |
7790df19 | 2602 | |
ab780373 | 2603 | if (TREE_READONLY (current_function_decl) |
bf6d9fd7 | 2604 | || DECL_IS_PURE (current_function_decl) |
7790df19 | 2605 | || TREE_THIS_VOLATILE (current_function_decl) |
ab780373 RH |
2606 | || current_function_has_nonlocal_goto |
2607 | || !(*targetm.binds_local_p) (current_function_decl)) | |
7790df19 JW |
2608 | return; |
2609 | ||
e004f2f7 | 2610 | /* A loop might not return which counts as a side effect. */ |
0ecf09f9 | 2611 | if (mark_dfs_back_edges ()) |
e004f2f7 JW |
2612 | return; |
2613 | ||
c14b9960 | 2614 | nonlocal_memory_referenced = 0; |
bf6d9fd7 JW |
2615 | |
2616 | init_alias_analysis (); | |
2617 | ||
c14b9960 | 2618 | /* Determine if this is a constant or pure function. */ |
7790df19 JW |
2619 | |
2620 | for (insn = get_insns (); insn; insn = NEXT_INSN (insn)) | |
c14b9960 JW |
2621 | { |
2622 | if (! INSN_P (insn)) | |
2623 | continue; | |
bf6d9fd7 | 2624 | |
c14b9960 JW |
2625 | if (nonlocal_set_p (insn) || global_reg_mentioned_p (insn) |
2626 | || volatile_refs_p (PATTERN (insn))) | |
ca7fd9cd | 2627 | break; |
7790df19 | 2628 | |
c14b9960 JW |
2629 | if (! nonlocal_memory_referenced) |
2630 | nonlocal_memory_referenced = nonlocal_referenced_p (insn); | |
2631 | } | |
ca7fd9cd | 2632 | |
c14b9960 | 2633 | end_alias_analysis (); |
ca7fd9cd | 2634 | |
7790df19 | 2635 | /* Mark the function. */ |
ca7fd9cd | 2636 | |
c14b9960 JW |
2637 | if (insn) |
2638 | ; | |
2639 | else if (nonlocal_memory_referenced) | |
c57ddcf1 RS |
2640 | { |
2641 | cgraph_rtl_info (current_function_decl)->pure_function = 1; | |
2642 | DECL_IS_PURE (current_function_decl) = 1; | |
2643 | } | |
c14b9960 | 2644 | else |
c57ddcf1 RS |
2645 | { |
2646 | cgraph_rtl_info (current_function_decl)->const_function = 1; | |
2647 | TREE_READONLY (current_function_decl) = 1; | |
2648 | } | |
7790df19 | 2649 | } |
c14b9960 | 2650 | \f |
6e73e666 | 2651 | |
6e73e666 | 2652 | void |
4682ae04 | 2653 | init_alias_once (void) |
6e73e666 | 2654 | { |
b3694847 | 2655 | int i; |
6e73e666 JC |
2656 | |
2657 | #ifndef OUTGOING_REGNO | |
2658 | #define OUTGOING_REGNO(N) N | |
2659 | #endif | |
2660 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) | |
2661 | /* Check whether this register can hold an incoming pointer | |
2662 | argument. FUNCTION_ARG_REGNO_P tests outgoing register | |
ec5c56db | 2663 | numbers, so translate if necessary due to register windows. */ |
6e73e666 JC |
2664 | if (FUNCTION_ARG_REGNO_P (OUTGOING_REGNO (i)) |
2665 | && HARD_REGNO_MODE_OK (i, Pmode)) | |
bf1660a6 JL |
2666 | static_reg_base_value[i] |
2667 | = gen_rtx_ADDRESS (VOIDmode, gen_rtx_REG (Pmode, i)); | |
2668 | ||
bf1660a6 JL |
2669 | static_reg_base_value[STACK_POINTER_REGNUM] |
2670 | = gen_rtx_ADDRESS (Pmode, stack_pointer_rtx); | |
2671 | static_reg_base_value[ARG_POINTER_REGNUM] | |
2672 | = gen_rtx_ADDRESS (Pmode, arg_pointer_rtx); | |
2673 | static_reg_base_value[FRAME_POINTER_REGNUM] | |
2674 | = gen_rtx_ADDRESS (Pmode, frame_pointer_rtx); | |
2675 | #if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM | |
2676 | static_reg_base_value[HARD_FRAME_POINTER_REGNUM] | |
2677 | = gen_rtx_ADDRESS (Pmode, hard_frame_pointer_rtx); | |
2678 | #endif | |
2679 | } | |
2680 | ||
7b52eede JH |
2681 | /* Set MEMORY_MODIFIED when X modifies DATA (that is assumed |
2682 | to be memory reference. */ | |
2683 | static bool memory_modified; | |
2684 | static void | |
4682ae04 | 2685 | memory_modified_1 (rtx x, rtx pat ATTRIBUTE_UNUSED, void *data) |
7b52eede JH |
2686 | { |
2687 | if (GET_CODE (x) == MEM) | |
2688 | { | |
2689 | if (anti_dependence (x, (rtx)data) || output_dependence (x, (rtx)data)) | |
2690 | memory_modified = true; | |
2691 | } | |
2692 | } | |
2693 | ||
2694 | ||
2695 | /* Return true when INSN possibly modify memory contents of MEM | |
2696 | (ie address can be modified). */ | |
2697 | bool | |
4682ae04 | 2698 | memory_modified_in_insn_p (rtx mem, rtx insn) |
7b52eede JH |
2699 | { |
2700 | if (!INSN_P (insn)) | |
2701 | return false; | |
2702 | memory_modified = false; | |
2703 | note_stores (PATTERN (insn), memory_modified_1, mem); | |
2704 | return memory_modified; | |
2705 | } | |
2706 | ||
c13e8210 MM |
2707 | /* Initialize the aliasing machinery. Initialize the REG_KNOWN_VALUE |
2708 | array. */ | |
2709 | ||
9ae8ffe7 | 2710 | void |
4682ae04 | 2711 | init_alias_analysis (void) |
9ae8ffe7 JL |
2712 | { |
2713 | int maxreg = max_reg_num (); | |
ea64ef27 | 2714 | int changed, pass; |
b3694847 SS |
2715 | int i; |
2716 | unsigned int ui; | |
2717 | rtx insn; | |
9ae8ffe7 | 2718 | |
0d446150 JH |
2719 | timevar_push (TV_ALIAS_ANALYSIS); |
2720 | ||
9ae8ffe7 JL |
2721 | reg_known_value_size = maxreg; |
2722 | ||
ca7fd9cd | 2723 | reg_known_value |
e05e2395 MM |
2724 | = (rtx *) xcalloc ((maxreg - FIRST_PSEUDO_REGISTER), sizeof (rtx)) |
2725 | - FIRST_PSEUDO_REGISTER; | |
ca7fd9cd | 2726 | reg_known_equiv_p |
e05e2395 | 2727 | = (char*) xcalloc ((maxreg - FIRST_PSEUDO_REGISTER), sizeof (char)) |
9ae8ffe7 | 2728 | - FIRST_PSEUDO_REGISTER; |
9ae8ffe7 | 2729 | |
6e73e666 JC |
2730 | /* Overallocate reg_base_value to allow some growth during loop |
2731 | optimization. Loop unrolling can create a large number of | |
2732 | registers. */ | |
2733 | reg_base_value_size = maxreg * 2; | |
703ad42b | 2734 | reg_base_value = ggc_alloc_cleared (reg_base_value_size * sizeof (rtx)); |
ac606739 | 2735 | |
703ad42b KG |
2736 | new_reg_base_value = xmalloc (reg_base_value_size * sizeof (rtx)); |
2737 | reg_seen = xmalloc (reg_base_value_size); | |
b17d5d7c | 2738 | if (! reload_completed && flag_old_unroll_loops) |
de12be17 | 2739 | { |
ac606739 | 2740 | /* ??? Why are we realloc'ing if we're just going to zero it? */ |
703ad42b KG |
2741 | alias_invariant = xrealloc (alias_invariant, |
2742 | reg_base_value_size * sizeof (rtx)); | |
2743 | memset (alias_invariant, 0, reg_base_value_size * sizeof (rtx)); | |
de12be17 | 2744 | } |
ec907dd8 JL |
2745 | |
2746 | /* The basic idea is that each pass through this loop will use the | |
2747 | "constant" information from the previous pass to propagate alias | |
2748 | information through another level of assignments. | |
2749 | ||
2750 | This could get expensive if the assignment chains are long. Maybe | |
2751 | we should throttle the number of iterations, possibly based on | |
6e73e666 | 2752 | the optimization level or flag_expensive_optimizations. |
ec907dd8 JL |
2753 | |
2754 | We could propagate more information in the first pass by making use | |
2755 | of REG_N_SETS to determine immediately that the alias information | |
ea64ef27 JL |
2756 | for a pseudo is "constant". |
2757 | ||
2758 | A program with an uninitialized variable can cause an infinite loop | |
2759 | here. Instead of doing a full dataflow analysis to detect such problems | |
2760 | we just cap the number of iterations for the loop. | |
2761 | ||
2762 | The state of the arrays for the set chain in question does not matter | |
2763 | since the program has undefined behavior. */ | |
6e73e666 | 2764 | |
ea64ef27 | 2765 | pass = 0; |
6e73e666 | 2766 | do |
ec907dd8 JL |
2767 | { |
2768 | /* Assume nothing will change this iteration of the loop. */ | |
2769 | changed = 0; | |
2770 | ||
ec907dd8 JL |
2771 | /* We want to assign the same IDs each iteration of this loop, so |
2772 | start counting from zero each iteration of the loop. */ | |
2773 | unique_id = 0; | |
2774 | ||
f5143c46 | 2775 | /* We're at the start of the function each iteration through the |
ec907dd8 | 2776 | loop, so we're copying arguments. */ |
83bbd9b6 | 2777 | copying_arguments = true; |
9ae8ffe7 | 2778 | |
6e73e666 | 2779 | /* Wipe the potential alias information clean for this pass. */ |
703ad42b | 2780 | memset (new_reg_base_value, 0, reg_base_value_size * sizeof (rtx)); |
8072f69c | 2781 | |
6e73e666 | 2782 | /* Wipe the reg_seen array clean. */ |
703ad42b | 2783 | memset (reg_seen, 0, reg_base_value_size); |
9ae8ffe7 | 2784 | |
6e73e666 JC |
2785 | /* Mark all hard registers which may contain an address. |
2786 | The stack, frame and argument pointers may contain an address. | |
2787 | An argument register which can hold a Pmode value may contain | |
2788 | an address even if it is not in BASE_REGS. | |
8072f69c | 2789 | |
6e73e666 JC |
2790 | The address expression is VOIDmode for an argument and |
2791 | Pmode for other registers. */ | |
2792 | ||
7f243674 JL |
2793 | memcpy (new_reg_base_value, static_reg_base_value, |
2794 | FIRST_PSEUDO_REGISTER * sizeof (rtx)); | |
6e73e666 | 2795 | |
ec907dd8 JL |
2796 | /* Walk the insns adding values to the new_reg_base_value array. */ |
2797 | for (insn = get_insns (); insn; insn = NEXT_INSN (insn)) | |
9ae8ffe7 | 2798 | { |
2c3c49de | 2799 | if (INSN_P (insn)) |
ec907dd8 | 2800 | { |
6e73e666 | 2801 | rtx note, set; |
efc9bd41 RK |
2802 | |
2803 | #if defined (HAVE_prologue) || defined (HAVE_epilogue) | |
f5143c46 | 2804 | /* The prologue/epilogue insns are not threaded onto the |
657959ca JL |
2805 | insn chain until after reload has completed. Thus, |
2806 | there is no sense wasting time checking if INSN is in | |
2807 | the prologue/epilogue until after reload has completed. */ | |
2808 | if (reload_completed | |
2809 | && prologue_epilogue_contains (insn)) | |
efc9bd41 RK |
2810 | continue; |
2811 | #endif | |
2812 | ||
ec907dd8 JL |
2813 | /* If this insn has a noalias note, process it, Otherwise, |
2814 | scan for sets. A simple set will have no side effects | |
ec5c56db | 2815 | which could change the base value of any other register. */ |
6e73e666 | 2816 | |
ec907dd8 | 2817 | if (GET_CODE (PATTERN (insn)) == SET |
efc9bd41 RK |
2818 | && REG_NOTES (insn) != 0 |
2819 | && find_reg_note (insn, REG_NOALIAS, NULL_RTX)) | |
84832317 | 2820 | record_set (SET_DEST (PATTERN (insn)), NULL_RTX, NULL); |
ec907dd8 | 2821 | else |
84832317 | 2822 | note_stores (PATTERN (insn), record_set, NULL); |
6e73e666 JC |
2823 | |
2824 | set = single_set (insn); | |
2825 | ||
2826 | if (set != 0 | |
2827 | && GET_CODE (SET_DEST (set)) == REG | |
fb6754f0 | 2828 | && REGNO (SET_DEST (set)) >= FIRST_PSEUDO_REGISTER) |
6e73e666 | 2829 | { |
fb6754f0 | 2830 | unsigned int regno = REGNO (SET_DEST (set)); |
713f41f9 BS |
2831 | rtx src = SET_SRC (set); |
2832 | ||
2833 | if (REG_NOTES (insn) != 0 | |
2834 | && (((note = find_reg_note (insn, REG_EQUAL, 0)) != 0 | |
2835 | && REG_N_SETS (regno) == 1) | |
2836 | || (note = find_reg_note (insn, REG_EQUIV, NULL_RTX)) != 0) | |
2837 | && GET_CODE (XEXP (note, 0)) != EXPR_LIST | |
bb2cf916 | 2838 | && ! rtx_varies_p (XEXP (note, 0), 1) |
713f41f9 BS |
2839 | && ! reg_overlap_mentioned_p (SET_DEST (set), XEXP (note, 0))) |
2840 | { | |
2841 | reg_known_value[regno] = XEXP (note, 0); | |
2842 | reg_known_equiv_p[regno] = REG_NOTE_KIND (note) == REG_EQUIV; | |
2843 | } | |
2844 | else if (REG_N_SETS (regno) == 1 | |
2845 | && GET_CODE (src) == PLUS | |
2846 | && GET_CODE (XEXP (src, 0)) == REG | |
fb6754f0 BS |
2847 | && REGNO (XEXP (src, 0)) >= FIRST_PSEUDO_REGISTER |
2848 | && (reg_known_value[REGNO (XEXP (src, 0))]) | |
713f41f9 BS |
2849 | && GET_CODE (XEXP (src, 1)) == CONST_INT) |
2850 | { | |
2851 | rtx op0 = XEXP (src, 0); | |
bb2cf916 | 2852 | op0 = reg_known_value[REGNO (op0)]; |
713f41f9 | 2853 | reg_known_value[regno] |
ed8908e7 | 2854 | = plus_constant (op0, INTVAL (XEXP (src, 1))); |
713f41f9 BS |
2855 | reg_known_equiv_p[regno] = 0; |
2856 | } | |
2857 | else if (REG_N_SETS (regno) == 1 | |
2858 | && ! rtx_varies_p (src, 1)) | |
2859 | { | |
2860 | reg_known_value[regno] = src; | |
2861 | reg_known_equiv_p[regno] = 0; | |
2862 | } | |
6e73e666 | 2863 | } |
ec907dd8 JL |
2864 | } |
2865 | else if (GET_CODE (insn) == NOTE | |
2866 | && NOTE_LINE_NUMBER (insn) == NOTE_INSN_FUNCTION_BEG) | |
83bbd9b6 | 2867 | copying_arguments = false; |
6e73e666 | 2868 | } |
ec907dd8 | 2869 | |
6e73e666 | 2870 | /* Now propagate values from new_reg_base_value to reg_base_value. */ |
e51712db | 2871 | for (ui = 0; ui < reg_base_value_size; ui++) |
6e73e666 | 2872 | { |
e51712db KG |
2873 | if (new_reg_base_value[ui] |
2874 | && new_reg_base_value[ui] != reg_base_value[ui] | |
2875 | && ! rtx_equal_p (new_reg_base_value[ui], reg_base_value[ui])) | |
ec907dd8 | 2876 | { |
e51712db | 2877 | reg_base_value[ui] = new_reg_base_value[ui]; |
6e73e666 | 2878 | changed = 1; |
ec907dd8 | 2879 | } |
9ae8ffe7 | 2880 | } |
9ae8ffe7 | 2881 | } |
6e73e666 | 2882 | while (changed && ++pass < MAX_ALIAS_LOOP_PASSES); |
9ae8ffe7 JL |
2883 | |
2884 | /* Fill in the remaining entries. */ | |
2885 | for (i = FIRST_PSEUDO_REGISTER; i < maxreg; i++) | |
2886 | if (reg_known_value[i] == 0) | |
2887 | reg_known_value[i] = regno_reg_rtx[i]; | |
2888 | ||
9ae8ffe7 JL |
2889 | /* Simplify the reg_base_value array so that no register refers to |
2890 | another register, except to special registers indirectly through | |
2891 | ADDRESS expressions. | |
2892 | ||
2893 | In theory this loop can take as long as O(registers^2), but unless | |
2894 | there are very long dependency chains it will run in close to linear | |
ea64ef27 JL |
2895 | time. |
2896 | ||
2897 | This loop may not be needed any longer now that the main loop does | |
2898 | a better job at propagating alias information. */ | |
2899 | pass = 0; | |
9ae8ffe7 JL |
2900 | do |
2901 | { | |
2902 | changed = 0; | |
ea64ef27 | 2903 | pass++; |
e51712db | 2904 | for (ui = 0; ui < reg_base_value_size; ui++) |
9ae8ffe7 | 2905 | { |
e51712db | 2906 | rtx base = reg_base_value[ui]; |
9ae8ffe7 JL |
2907 | if (base && GET_CODE (base) == REG) |
2908 | { | |
fb6754f0 | 2909 | unsigned int base_regno = REGNO (base); |
e51712db KG |
2910 | if (base_regno == ui) /* register set from itself */ |
2911 | reg_base_value[ui] = 0; | |
9ae8ffe7 | 2912 | else |
e51712db | 2913 | reg_base_value[ui] = reg_base_value[base_regno]; |
9ae8ffe7 JL |
2914 | changed = 1; |
2915 | } | |
2916 | } | |
2917 | } | |
ea64ef27 | 2918 | while (changed && pass < MAX_ALIAS_LOOP_PASSES); |
9ae8ffe7 | 2919 | |
e05e2395 MM |
2920 | /* Clean up. */ |
2921 | free (new_reg_base_value); | |
ec907dd8 | 2922 | new_reg_base_value = 0; |
e05e2395 | 2923 | free (reg_seen); |
9ae8ffe7 | 2924 | reg_seen = 0; |
0d446150 | 2925 | timevar_pop (TV_ALIAS_ANALYSIS); |
9ae8ffe7 JL |
2926 | } |
2927 | ||
2928 | void | |
4682ae04 | 2929 | end_alias_analysis (void) |
9ae8ffe7 | 2930 | { |
e05e2395 | 2931 | free (reg_known_value + FIRST_PSEUDO_REGISTER); |
9ae8ffe7 | 2932 | reg_known_value = 0; |
ac606739 | 2933 | reg_known_value_size = 0; |
e05e2395 MM |
2934 | free (reg_known_equiv_p + FIRST_PSEUDO_REGISTER); |
2935 | reg_known_equiv_p = 0; | |
e2500fed | 2936 | reg_base_value = 0; |
9ae8ffe7 | 2937 | reg_base_value_size = 0; |
de12be17 JC |
2938 | if (alias_invariant) |
2939 | { | |
ac606739 | 2940 | free (alias_invariant); |
de12be17 JC |
2941 | alias_invariant = 0; |
2942 | } | |
9ae8ffe7 | 2943 | } |
e2500fed GK |
2944 | |
2945 | #include "gt-alias.h" |