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9ae8ffe7 | 1 | /* Alias analysis for GNU C |
1afdf91c RH |
2 | Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003 |
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" |
ab780373 | 42 | #include "target.h" |
3932261a MM |
43 | |
44 | /* The alias sets assigned to MEMs assist the back-end in determining | |
45 | which MEMs can alias which other MEMs. In general, two MEMs in | |
ac3d9668 RK |
46 | different alias sets cannot alias each other, with one important |
47 | exception. Consider something like: | |
3932261a MM |
48 | |
49 | struct S {int i; double d; }; | |
50 | ||
51 | a store to an `S' can alias something of either type `int' or type | |
52 | `double'. (However, a store to an `int' cannot alias a `double' | |
53 | and vice versa.) We indicate this via a tree structure that looks | |
54 | like: | |
55 | struct S | |
56 | / \ | |
57 | / \ | |
58 | |/_ _\| | |
59 | int double | |
60 | ||
ac3d9668 RK |
61 | (The arrows are directed and point downwards.) |
62 | In this situation we say the alias set for `struct S' is the | |
63 | `superset' and that those for `int' and `double' are `subsets'. | |
64 | ||
3bdf5ad1 RK |
65 | To see whether two alias sets can point to the same memory, we must |
66 | see if either alias set is a subset of the other. We need not trace | |
e3aafbad | 67 | past immediate descendents, however, since we propagate all |
3bdf5ad1 | 68 | grandchildren up one level. |
3932261a MM |
69 | |
70 | Alias set zero is implicitly a superset of all other alias sets. | |
71 | However, this is no actual entry for alias set zero. It is an | |
72 | error to attempt to explicitly construct a subset of zero. */ | |
73 | ||
d4b60170 RK |
74 | typedef struct alias_set_entry |
75 | { | |
3932261a | 76 | /* The alias set number, as stored in MEM_ALIAS_SET. */ |
3bdf5ad1 | 77 | HOST_WIDE_INT alias_set; |
3932261a MM |
78 | |
79 | /* The children of the alias set. These are not just the immediate | |
e3aafbad | 80 | children, but, in fact, all descendents. So, if we have: |
3932261a | 81 | |
ca7fd9cd | 82 | struct T { struct S s; float f; } |
3932261a MM |
83 | |
84 | continuing our example above, the children here will be all of | |
85 | `int', `double', `float', and `struct S'. */ | |
86 | splay_tree children; | |
2bf105ab RK |
87 | |
88 | /* Nonzero if would have a child of zero: this effectively makes this | |
89 | alias set the same as alias set zero. */ | |
90 | int has_zero_child; | |
d4b60170 | 91 | } *alias_set_entry; |
9ae8ffe7 | 92 | |
3d994c6b KG |
93 | static int rtx_equal_for_memref_p PARAMS ((rtx, rtx)); |
94 | static rtx find_symbolic_term PARAMS ((rtx)); | |
a13d4ebf | 95 | rtx get_addr PARAMS ((rtx)); |
3d994c6b KG |
96 | static int memrefs_conflict_p PARAMS ((int, rtx, int, rtx, |
97 | HOST_WIDE_INT)); | |
98 | static void record_set PARAMS ((rtx, rtx, void *)); | |
99 | static rtx find_base_term PARAMS ((rtx)); | |
100 | static int base_alias_check PARAMS ((rtx, rtx, enum machine_mode, | |
101 | enum machine_mode)); | |
102 | static rtx find_base_value PARAMS ((rtx)); | |
103 | static int mems_in_disjoint_alias_sets_p PARAMS ((rtx, rtx)); | |
104 | static int insert_subset_children PARAMS ((splay_tree_node, void*)); | |
738cc472 | 105 | static tree find_base_decl PARAMS ((tree)); |
3bdf5ad1 | 106 | static alias_set_entry get_alias_set_entry PARAMS ((HOST_WIDE_INT)); |
eab5c70a | 107 | static rtx fixed_scalar_and_varying_struct_p PARAMS ((rtx, rtx, rtx, rtx, |
e38fe8e0 | 108 | int (*) (rtx, int))); |
3d994c6b | 109 | static int aliases_everything_p PARAMS ((rtx)); |
998d7deb RH |
110 | static bool nonoverlapping_component_refs_p PARAMS ((tree, tree)); |
111 | static tree decl_for_component_ref PARAMS ((tree)); | |
112 | static rtx adjust_offset_for_component_ref PARAMS ((tree, rtx)); | |
a4311dfe | 113 | static int nonoverlapping_memrefs_p PARAMS ((rtx, rtx)); |
3d994c6b | 114 | static int write_dependence_p PARAMS ((rtx, rtx, int)); |
c14b9960 JW |
115 | |
116 | static int nonlocal_mentioned_p_1 PARAMS ((rtx *, void *)); | |
bf6d9fd7 | 117 | static int nonlocal_mentioned_p PARAMS ((rtx)); |
c14b9960 JW |
118 | static int nonlocal_referenced_p_1 PARAMS ((rtx *, void *)); |
119 | static int nonlocal_referenced_p PARAMS ((rtx)); | |
120 | static int nonlocal_set_p_1 PARAMS ((rtx *, void *)); | |
121 | static int nonlocal_set_p PARAMS ((rtx)); | |
9ae8ffe7 JL |
122 | |
123 | /* Set up all info needed to perform alias analysis on memory references. */ | |
124 | ||
d4b60170 | 125 | /* Returns the size in bytes of the mode of X. */ |
9ae8ffe7 JL |
126 | #define SIZE_FOR_MODE(X) (GET_MODE_SIZE (GET_MODE (X))) |
127 | ||
41472af8 | 128 | /* Returns nonzero if MEM1 and MEM2 do not alias because they are in |
264fac34 MM |
129 | different alias sets. We ignore alias sets in functions making use |
130 | of variable arguments because the va_arg macros on some systems are | |
131 | not legal ANSI C. */ | |
132 | #define DIFFERENT_ALIAS_SETS_P(MEM1, MEM2) \ | |
3932261a | 133 | mems_in_disjoint_alias_sets_p (MEM1, MEM2) |
41472af8 | 134 | |
ea64ef27 | 135 | /* Cap the number of passes we make over the insns propagating alias |
ac3d9668 | 136 | information through set chains. 10 is a completely arbitrary choice. */ |
ea64ef27 | 137 | #define MAX_ALIAS_LOOP_PASSES 10 |
ca7fd9cd | 138 | |
9ae8ffe7 JL |
139 | /* reg_base_value[N] gives an address to which register N is related. |
140 | If all sets after the first add or subtract to the current value | |
141 | or otherwise modify it so it does not point to a different top level | |
142 | object, reg_base_value[N] is equal to the address part of the source | |
2a2c8203 JC |
143 | of the first set. |
144 | ||
145 | A base address can be an ADDRESS, SYMBOL_REF, or LABEL_REF. ADDRESS | |
146 | expressions represent certain special values: function arguments and | |
ca7fd9cd | 147 | the stack, frame, and argument pointers. |
b3b5ad95 JL |
148 | |
149 | The contents of an ADDRESS is not normally used, the mode of the | |
150 | ADDRESS determines whether the ADDRESS is a function argument or some | |
151 | other special value. Pointer equality, not rtx_equal_p, determines whether | |
152 | two ADDRESS expressions refer to the same base address. | |
153 | ||
154 | The only use of the contents of an ADDRESS is for determining if the | |
155 | current function performs nonlocal memory memory references for the | |
156 | purposes of marking the function as a constant function. */ | |
2a2c8203 | 157 | |
e2500fed | 158 | static GTY((length ("reg_base_value_size"))) rtx *reg_base_value; |
ac606739 | 159 | static rtx *new_reg_base_value; |
d4b60170 RK |
160 | static unsigned int reg_base_value_size; /* size of reg_base_value array */ |
161 | ||
bf1660a6 JL |
162 | /* Static hunks of RTL used by the aliasing code; these are initialized |
163 | once per function to avoid unnecessary RTL allocations. */ | |
164 | static GTY (()) rtx static_reg_base_value[FIRST_PSEUDO_REGISTER]; | |
165 | ||
9ae8ffe7 | 166 | #define REG_BASE_VALUE(X) \ |
fb6754f0 BS |
167 | (REGNO (X) < reg_base_value_size \ |
168 | ? reg_base_value[REGNO (X)] : 0) | |
9ae8ffe7 | 169 | |
de12be17 JC |
170 | /* Vector of known invariant relationships between registers. Set in |
171 | loop unrolling. Indexed by register number, if nonzero the value | |
172 | is an expression describing this register in terms of another. | |
173 | ||
174 | The length of this array is REG_BASE_VALUE_SIZE. | |
175 | ||
176 | Because this array contains only pseudo registers it has no effect | |
177 | after reload. */ | |
178 | static rtx *alias_invariant; | |
179 | ||
c13e8210 MM |
180 | /* Vector indexed by N giving the initial (unchanging) value known for |
181 | pseudo-register N. This array is initialized in | |
182 | init_alias_analysis, and does not change until end_alias_analysis | |
183 | is called. */ | |
9ae8ffe7 JL |
184 | rtx *reg_known_value; |
185 | ||
186 | /* Indicates number of valid entries in reg_known_value. */ | |
770ae6cc | 187 | static unsigned int reg_known_value_size; |
9ae8ffe7 JL |
188 | |
189 | /* Vector recording for each reg_known_value whether it is due to a | |
190 | REG_EQUIV note. Future passes (viz., reload) may replace the | |
191 | pseudo with the equivalent expression and so we account for the | |
ac3d9668 RK |
192 | dependences that would be introduced if that happens. |
193 | ||
194 | The REG_EQUIV notes created in assign_parms may mention the arg | |
195 | pointer, and there are explicit insns in the RTL that modify the | |
196 | arg pointer. Thus we must ensure that such insns don't get | |
197 | scheduled across each other because that would invalidate the | |
198 | REG_EQUIV notes. One could argue that the REG_EQUIV notes are | |
199 | wrong, but solving the problem in the scheduler will likely give | |
200 | better code, so we do it here. */ | |
9ae8ffe7 JL |
201 | char *reg_known_equiv_p; |
202 | ||
2a2c8203 JC |
203 | /* True when scanning insns from the start of the rtl to the |
204 | NOTE_INSN_FUNCTION_BEG note. */ | |
83bbd9b6 | 205 | static bool copying_arguments; |
9ae8ffe7 | 206 | |
3932261a | 207 | /* The splay-tree used to store the various alias set entries. */ |
3932261a | 208 | static splay_tree alias_sets; |
ac3d9668 | 209 | \f |
3932261a MM |
210 | /* Returns a pointer to the alias set entry for ALIAS_SET, if there is |
211 | such an entry, or NULL otherwise. */ | |
212 | ||
213 | static alias_set_entry | |
214 | get_alias_set_entry (alias_set) | |
3bdf5ad1 | 215 | HOST_WIDE_INT alias_set; |
3932261a | 216 | { |
d4b60170 RK |
217 | splay_tree_node sn |
218 | = splay_tree_lookup (alias_sets, (splay_tree_key) alias_set); | |
3932261a | 219 | |
d4b60170 | 220 | return sn != 0 ? ((alias_set_entry) sn->value) : 0; |
3932261a MM |
221 | } |
222 | ||
ac3d9668 RK |
223 | /* Returns nonzero if the alias sets for MEM1 and MEM2 are such that |
224 | the two MEMs cannot alias each other. */ | |
3932261a | 225 | |
ca7fd9cd | 226 | static int |
3932261a MM |
227 | mems_in_disjoint_alias_sets_p (mem1, mem2) |
228 | rtx mem1; | |
229 | rtx mem2; | |
230 | { | |
ca7fd9cd | 231 | #ifdef ENABLE_CHECKING |
3932261a MM |
232 | /* Perform a basic sanity check. Namely, that there are no alias sets |
233 | if we're not using strict aliasing. This helps to catch bugs | |
234 | whereby someone uses PUT_CODE, but doesn't clear MEM_ALIAS_SET, or | |
235 | where a MEM is allocated in some way other than by the use of | |
236 | gen_rtx_MEM, and the MEM_ALIAS_SET is not cleared. If we begin to | |
237 | use alias sets to indicate that spilled registers cannot alias each | |
238 | other, we might need to remove this check. */ | |
d4b60170 RK |
239 | if (! flag_strict_aliasing |
240 | && (MEM_ALIAS_SET (mem1) != 0 || MEM_ALIAS_SET (mem2) != 0)) | |
3932261a MM |
241 | abort (); |
242 | #endif | |
243 | ||
1da68f56 RK |
244 | return ! alias_sets_conflict_p (MEM_ALIAS_SET (mem1), MEM_ALIAS_SET (mem2)); |
245 | } | |
3932261a | 246 | |
1da68f56 RK |
247 | /* Insert the NODE into the splay tree given by DATA. Used by |
248 | record_alias_subset via splay_tree_foreach. */ | |
249 | ||
250 | static int | |
251 | insert_subset_children (node, data) | |
252 | splay_tree_node node; | |
253 | void *data; | |
254 | { | |
255 | splay_tree_insert ((splay_tree) data, node->key, node->value); | |
256 | ||
257 | return 0; | |
258 | } | |
259 | ||
260 | /* Return 1 if the two specified alias sets may conflict. */ | |
261 | ||
262 | int | |
263 | alias_sets_conflict_p (set1, set2) | |
264 | HOST_WIDE_INT set1, set2; | |
265 | { | |
266 | alias_set_entry ase; | |
267 | ||
268 | /* If have no alias set information for one of the operands, we have | |
269 | to assume it can alias anything. */ | |
270 | if (set1 == 0 || set2 == 0 | |
271 | /* If the two alias sets are the same, they may alias. */ | |
272 | || set1 == set2) | |
273 | return 1; | |
3932261a | 274 | |
3bdf5ad1 | 275 | /* See if the first alias set is a subset of the second. */ |
1da68f56 | 276 | ase = get_alias_set_entry (set1); |
2bf105ab RK |
277 | if (ase != 0 |
278 | && (ase->has_zero_child | |
279 | || splay_tree_lookup (ase->children, | |
1da68f56 RK |
280 | (splay_tree_key) set2))) |
281 | return 1; | |
3932261a MM |
282 | |
283 | /* Now do the same, but with the alias sets reversed. */ | |
1da68f56 | 284 | ase = get_alias_set_entry (set2); |
2bf105ab RK |
285 | if (ase != 0 |
286 | && (ase->has_zero_child | |
287 | || splay_tree_lookup (ase->children, | |
1da68f56 RK |
288 | (splay_tree_key) set1))) |
289 | return 1; | |
3932261a | 290 | |
1da68f56 | 291 | /* The two alias sets are distinct and neither one is the |
3932261a | 292 | child of the other. Therefore, they cannot alias. */ |
1da68f56 | 293 | return 0; |
3932261a | 294 | } |
1da68f56 RK |
295 | \f |
296 | /* Return 1 if TYPE is a RECORD_TYPE, UNION_TYPE, or QUAL_UNION_TYPE and has | |
297 | has any readonly fields. If any of the fields have types that | |
298 | contain readonly fields, return true as well. */ | |
3932261a | 299 | |
1da68f56 RK |
300 | int |
301 | readonly_fields_p (type) | |
302 | tree type; | |
3932261a | 303 | { |
1da68f56 RK |
304 | tree field; |
305 | ||
306 | if (TREE_CODE (type) != RECORD_TYPE && TREE_CODE (type) != UNION_TYPE | |
307 | && TREE_CODE (type) != QUAL_UNION_TYPE) | |
308 | return 0; | |
309 | ||
310 | for (field = TYPE_FIELDS (type); field != 0; field = TREE_CHAIN (field)) | |
311 | if (TREE_CODE (field) == FIELD_DECL | |
312 | && (TREE_READONLY (field) | |
313 | || readonly_fields_p (TREE_TYPE (field)))) | |
314 | return 1; | |
3932261a MM |
315 | |
316 | return 0; | |
317 | } | |
3bdf5ad1 | 318 | \f |
1da68f56 RK |
319 | /* Return 1 if any MEM object of type T1 will always conflict (using the |
320 | dependency routines in this file) with any MEM object of type T2. | |
321 | This is used when allocating temporary storage. If T1 and/or T2 are | |
322 | NULL_TREE, it means we know nothing about the storage. */ | |
323 | ||
324 | int | |
325 | objects_must_conflict_p (t1, t2) | |
326 | tree t1, t2; | |
327 | { | |
e8ea2809 RK |
328 | /* If neither has a type specified, we don't know if they'll conflict |
329 | because we may be using them to store objects of various types, for | |
330 | example the argument and local variables areas of inlined functions. */ | |
981a4c34 | 331 | if (t1 == 0 && t2 == 0) |
e8ea2809 RK |
332 | return 0; |
333 | ||
66cce54d RH |
334 | /* If one or the other has readonly fields or is readonly, |
335 | then they may not conflict. */ | |
336 | if ((t1 != 0 && readonly_fields_p (t1)) | |
337 | || (t2 != 0 && readonly_fields_p (t2)) | |
a3b88570 MM |
338 | || (t1 != 0 && lang_hooks.honor_readonly && TYPE_READONLY (t1)) |
339 | || (t2 != 0 && lang_hooks.honor_readonly && TYPE_READONLY (t2))) | |
66cce54d RH |
340 | return 0; |
341 | ||
1da68f56 RK |
342 | /* If they are the same type, they must conflict. */ |
343 | if (t1 == t2 | |
344 | /* Likewise if both are volatile. */ | |
345 | || (t1 != 0 && TYPE_VOLATILE (t1) && t2 != 0 && TYPE_VOLATILE (t2))) | |
346 | return 1; | |
347 | ||
66cce54d RH |
348 | /* If one is aggregate and the other is scalar then they may not |
349 | conflict. */ | |
350 | if ((t1 != 0 && AGGREGATE_TYPE_P (t1)) | |
351 | != (t2 != 0 && AGGREGATE_TYPE_P (t2))) | |
1da68f56 RK |
352 | return 0; |
353 | ||
ec5c56db | 354 | /* Otherwise they conflict only if the alias sets conflict. */ |
1da68f56 RK |
355 | return alias_sets_conflict_p (t1 ? get_alias_set (t1) : 0, |
356 | t2 ? get_alias_set (t2) : 0); | |
357 | } | |
358 | \f | |
3bdf5ad1 RK |
359 | /* T is an expression with pointer type. Find the DECL on which this |
360 | expression is based. (For example, in `a[i]' this would be `a'.) | |
361 | If there is no such DECL, or a unique decl cannot be determined, | |
f5143c46 | 362 | NULL_TREE is returned. */ |
3bdf5ad1 RK |
363 | |
364 | static tree | |
365 | find_base_decl (t) | |
366 | tree t; | |
367 | { | |
368 | tree d0, d1, d2; | |
369 | ||
370 | if (t == 0 || t == error_mark_node || ! POINTER_TYPE_P (TREE_TYPE (t))) | |
371 | return 0; | |
372 | ||
373 | /* If this is a declaration, return it. */ | |
374 | if (TREE_CODE_CLASS (TREE_CODE (t)) == 'd') | |
375 | return t; | |
376 | ||
377 | /* Handle general expressions. It would be nice to deal with | |
378 | COMPONENT_REFs here. If we could tell that `a' and `b' were the | |
379 | same, then `a->f' and `b->f' are also the same. */ | |
380 | switch (TREE_CODE_CLASS (TREE_CODE (t))) | |
381 | { | |
382 | case '1': | |
383 | return find_base_decl (TREE_OPERAND (t, 0)); | |
384 | ||
385 | case '2': | |
386 | /* Return 0 if found in neither or both are the same. */ | |
387 | d0 = find_base_decl (TREE_OPERAND (t, 0)); | |
388 | d1 = find_base_decl (TREE_OPERAND (t, 1)); | |
389 | if (d0 == d1) | |
390 | return d0; | |
391 | else if (d0 == 0) | |
392 | return d1; | |
393 | else if (d1 == 0) | |
394 | return d0; | |
395 | else | |
396 | return 0; | |
397 | ||
398 | case '3': | |
399 | d0 = find_base_decl (TREE_OPERAND (t, 0)); | |
400 | d1 = find_base_decl (TREE_OPERAND (t, 1)); | |
3bdf5ad1 RK |
401 | d2 = find_base_decl (TREE_OPERAND (t, 2)); |
402 | ||
403 | /* Set any nonzero values from the last, then from the first. */ | |
404 | if (d1 == 0) d1 = d2; | |
405 | if (d0 == 0) d0 = d1; | |
406 | if (d1 == 0) d1 = d0; | |
407 | if (d2 == 0) d2 = d1; | |
408 | ||
409 | /* At this point all are nonzero or all are zero. If all three are the | |
410 | same, return it. Otherwise, return zero. */ | |
411 | return (d0 == d1 && d1 == d2) ? d0 : 0; | |
412 | ||
413 | default: | |
414 | return 0; | |
415 | } | |
416 | } | |
417 | ||
6e24b709 RK |
418 | /* Return 1 if all the nested component references handled by |
419 | get_inner_reference in T are such that we can address the object in T. */ | |
420 | ||
10b76d73 | 421 | int |
6e24b709 RK |
422 | can_address_p (t) |
423 | tree t; | |
424 | { | |
425 | /* If we're at the end, it is vacuously addressable. */ | |
426 | if (! handled_component_p (t)) | |
427 | return 1; | |
428 | ||
429 | /* Bitfields are never addressable. */ | |
430 | else if (TREE_CODE (t) == BIT_FIELD_REF) | |
431 | return 0; | |
432 | ||
8ac61af7 RK |
433 | /* Fields are addressable unless they are marked as nonaddressable or |
434 | the containing type has alias set 0. */ | |
6e24b709 RK |
435 | else if (TREE_CODE (t) == COMPONENT_REF |
436 | && ! DECL_NONADDRESSABLE_P (TREE_OPERAND (t, 1)) | |
8ac61af7 | 437 | && get_alias_set (TREE_TYPE (TREE_OPERAND (t, 0))) != 0 |
6e24b709 RK |
438 | && can_address_p (TREE_OPERAND (t, 0))) |
439 | return 1; | |
440 | ||
8ac61af7 | 441 | /* Likewise for arrays. */ |
b4e3fabb | 442 | else if ((TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF) |
6e24b709 | 443 | && ! TYPE_NONALIASED_COMPONENT (TREE_TYPE (TREE_OPERAND (t, 0))) |
8ac61af7 | 444 | && get_alias_set (TREE_TYPE (TREE_OPERAND (t, 0))) != 0 |
6e24b709 RK |
445 | && can_address_p (TREE_OPERAND (t, 0))) |
446 | return 1; | |
447 | ||
448 | return 0; | |
449 | } | |
450 | ||
3bdf5ad1 RK |
451 | /* Return the alias set for T, which may be either a type or an |
452 | expression. Call language-specific routine for help, if needed. */ | |
453 | ||
454 | HOST_WIDE_INT | |
455 | get_alias_set (t) | |
456 | tree t; | |
457 | { | |
458 | HOST_WIDE_INT set; | |
3bdf5ad1 RK |
459 | |
460 | /* If we're not doing any alias analysis, just assume everything | |
461 | aliases everything else. Also return 0 if this or its type is | |
462 | an error. */ | |
463 | if (! flag_strict_aliasing || t == error_mark_node | |
464 | || (! TYPE_P (t) | |
465 | && (TREE_TYPE (t) == 0 || TREE_TYPE (t) == error_mark_node))) | |
466 | return 0; | |
467 | ||
468 | /* We can be passed either an expression or a type. This and the | |
f47e9b4e RK |
469 | language-specific routine may make mutually-recursive calls to each other |
470 | to figure out what to do. At each juncture, we see if this is a tree | |
471 | that the language may need to handle specially. First handle things that | |
738cc472 | 472 | aren't types. */ |
f824e5c3 | 473 | if (! TYPE_P (t)) |
3bdf5ad1 | 474 | { |
738cc472 RK |
475 | tree inner = t; |
476 | tree placeholder_ptr = 0; | |
477 | ||
8ac61af7 RK |
478 | /* Remove any nops, then give the language a chance to do |
479 | something with this tree before we look at it. */ | |
480 | STRIP_NOPS (t); | |
481 | set = (*lang_hooks.get_alias_set) (t); | |
482 | if (set != -1) | |
483 | return set; | |
484 | ||
738cc472 | 485 | /* First see if the actual object referenced is an INDIRECT_REF from a |
8ac61af7 | 486 | restrict-qualified pointer or a "void *". Replace |
738cc472 | 487 | PLACEHOLDER_EXPRs. */ |
8ac61af7 | 488 | while (TREE_CODE (inner) == PLACEHOLDER_EXPR |
738cc472 RK |
489 | || handled_component_p (inner)) |
490 | { | |
491 | if (TREE_CODE (inner) == PLACEHOLDER_EXPR) | |
492 | inner = find_placeholder (inner, &placeholder_ptr); | |
493 | else | |
494 | inner = TREE_OPERAND (inner, 0); | |
8ac61af7 RK |
495 | |
496 | STRIP_NOPS (inner); | |
738cc472 RK |
497 | } |
498 | ||
499 | /* Check for accesses through restrict-qualified pointers. */ | |
500 | if (TREE_CODE (inner) == INDIRECT_REF) | |
501 | { | |
502 | tree decl = find_base_decl (TREE_OPERAND (inner, 0)); | |
503 | ||
504 | if (decl && DECL_POINTER_ALIAS_SET_KNOWN_P (decl)) | |
505 | { | |
e5837c07 | 506 | /* If we haven't computed the actual alias set, do it now. */ |
738cc472 RK |
507 | if (DECL_POINTER_ALIAS_SET (decl) == -2) |
508 | { | |
509 | /* No two restricted pointers can point at the same thing. | |
510 | However, a restricted pointer can point at the same thing | |
511 | as an unrestricted pointer, if that unrestricted pointer | |
512 | is based on the restricted pointer. So, we make the | |
513 | alias set for the restricted pointer a subset of the | |
514 | alias set for the type pointed to by the type of the | |
515 | decl. */ | |
516 | HOST_WIDE_INT pointed_to_alias_set | |
517 | = get_alias_set (TREE_TYPE (TREE_TYPE (decl))); | |
518 | ||
519 | if (pointed_to_alias_set == 0) | |
520 | /* It's not legal to make a subset of alias set zero. */ | |
521 | ; | |
522 | else | |
523 | { | |
524 | DECL_POINTER_ALIAS_SET (decl) = new_alias_set (); | |
ca7fd9cd KH |
525 | record_alias_subset (pointed_to_alias_set, |
526 | DECL_POINTER_ALIAS_SET (decl)); | |
738cc472 RK |
527 | } |
528 | } | |
529 | ||
530 | /* We use the alias set indicated in the declaration. */ | |
531 | return DECL_POINTER_ALIAS_SET (decl); | |
532 | } | |
533 | ||
534 | /* If we have an INDIRECT_REF via a void pointer, we don't | |
535 | know anything about what that might alias. */ | |
536 | else if (TREE_CODE (TREE_TYPE (inner)) == VOID_TYPE) | |
537 | return 0; | |
538 | } | |
539 | ||
540 | /* Otherwise, pick up the outermost object that we could have a pointer | |
541 | to, processing conversion and PLACEHOLDER_EXPR as above. */ | |
542 | placeholder_ptr = 0; | |
8ac61af7 | 543 | while (TREE_CODE (t) == PLACEHOLDER_EXPR |
f47e9b4e RK |
544 | || (handled_component_p (t) && ! can_address_p (t))) |
545 | { | |
f47e9b4e | 546 | if (TREE_CODE (t) == PLACEHOLDER_EXPR) |
738cc472 | 547 | t = find_placeholder (t, &placeholder_ptr); |
f47e9b4e RK |
548 | else |
549 | t = TREE_OPERAND (t, 0); | |
f824e5c3 | 550 | |
8ac61af7 RK |
551 | STRIP_NOPS (t); |
552 | } | |
f824e5c3 | 553 | |
738cc472 RK |
554 | /* If we've already determined the alias set for a decl, just return |
555 | it. This is necessary for C++ anonymous unions, whose component | |
556 | variables don't look like union members (boo!). */ | |
5755cd38 JM |
557 | if (TREE_CODE (t) == VAR_DECL |
558 | && DECL_RTL_SET_P (t) && GET_CODE (DECL_RTL (t)) == MEM) | |
559 | return MEM_ALIAS_SET (DECL_RTL (t)); | |
560 | ||
f824e5c3 RK |
561 | /* Now all we care about is the type. */ |
562 | t = TREE_TYPE (t); | |
3bdf5ad1 RK |
563 | } |
564 | ||
3bdf5ad1 RK |
565 | /* Variant qualifiers don't affect the alias set, so get the main |
566 | variant. If this is a type with a known alias set, return it. */ | |
567 | t = TYPE_MAIN_VARIANT (t); | |
738cc472 | 568 | if (TYPE_ALIAS_SET_KNOWN_P (t)) |
3bdf5ad1 RK |
569 | return TYPE_ALIAS_SET (t); |
570 | ||
571 | /* See if the language has special handling for this type. */ | |
8ac61af7 RK |
572 | set = (*lang_hooks.get_alias_set) (t); |
573 | if (set != -1) | |
738cc472 | 574 | return set; |
2bf105ab | 575 | |
3bdf5ad1 RK |
576 | /* There are no objects of FUNCTION_TYPE, so there's no point in |
577 | using up an alias set for them. (There are, of course, pointers | |
578 | and references to functions, but that's different.) */ | |
579 | else if (TREE_CODE (t) == FUNCTION_TYPE) | |
580 | set = 0; | |
74d86f4f RH |
581 | |
582 | /* Unless the language specifies otherwise, let vector types alias | |
583 | their components. This avoids some nasty type punning issues in | |
584 | normal usage. And indeed lets vectors be treated more like an | |
585 | array slice. */ | |
586 | else if (TREE_CODE (t) == VECTOR_TYPE) | |
587 | set = get_alias_set (TREE_TYPE (t)); | |
588 | ||
3bdf5ad1 RK |
589 | else |
590 | /* Otherwise make a new alias set for this type. */ | |
591 | set = new_alias_set (); | |
592 | ||
593 | TYPE_ALIAS_SET (t) = set; | |
2bf105ab RK |
594 | |
595 | /* If this is an aggregate type, we must record any component aliasing | |
596 | information. */ | |
1d79fd2c | 597 | if (AGGREGATE_TYPE_P (t) || TREE_CODE (t) == COMPLEX_TYPE) |
2bf105ab RK |
598 | record_component_aliases (t); |
599 | ||
3bdf5ad1 RK |
600 | return set; |
601 | } | |
602 | ||
603 | /* Return a brand-new alias set. */ | |
604 | ||
605 | HOST_WIDE_INT | |
606 | new_alias_set () | |
607 | { | |
608 | static HOST_WIDE_INT last_alias_set; | |
609 | ||
610 | if (flag_strict_aliasing) | |
611 | return ++last_alias_set; | |
612 | else | |
613 | return 0; | |
614 | } | |
3932261a MM |
615 | |
616 | /* Indicate that things in SUBSET can alias things in SUPERSET, but | |
617 | not vice versa. For example, in C, a store to an `int' can alias a | |
618 | structure containing an `int', but not vice versa. Here, the | |
619 | structure would be the SUPERSET and `int' the SUBSET. This | |
ca7fd9cd | 620 | 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 | |
626 | record_alias_subset (superset, subset) | |
3bdf5ad1 RK |
627 | HOST_WIDE_INT superset; |
628 | HOST_WIDE_INT subset; | |
3932261a MM |
629 | { |
630 | alias_set_entry superset_entry; | |
631 | alias_set_entry subset_entry; | |
632 | ||
f47e9b4e RK |
633 | /* It is possible in complex type situations for both sets to be the same, |
634 | in which case we can ignore this operation. */ | |
635 | if (superset == subset) | |
636 | return; | |
637 | ||
3932261a MM |
638 | if (superset == 0) |
639 | abort (); | |
640 | ||
641 | superset_entry = get_alias_set_entry (superset); | |
ca7fd9cd | 642 | if (superset_entry == 0) |
3932261a MM |
643 | { |
644 | /* Create an entry for the SUPERSET, so that we have a place to | |
645 | attach the SUBSET. */ | |
d4b60170 RK |
646 | superset_entry |
647 | = (alias_set_entry) xmalloc (sizeof (struct alias_set_entry)); | |
3932261a | 648 | superset_entry->alias_set = superset; |
ca7fd9cd | 649 | superset_entry->children |
30f72379 | 650 | = splay_tree_new (splay_tree_compare_ints, 0, 0); |
570eb5c8 | 651 | superset_entry->has_zero_child = 0; |
d4b60170 | 652 | splay_tree_insert (alias_sets, (splay_tree_key) superset, |
3932261a | 653 | (splay_tree_value) superset_entry); |
3932261a MM |
654 | } |
655 | ||
2bf105ab RK |
656 | if (subset == 0) |
657 | superset_entry->has_zero_child = 1; | |
658 | else | |
659 | { | |
660 | subset_entry = get_alias_set_entry (subset); | |
661 | /* If there is an entry for the subset, enter all of its children | |
662 | (if they are not already present) as children of the SUPERSET. */ | |
ca7fd9cd | 663 | if (subset_entry) |
2bf105ab RK |
664 | { |
665 | if (subset_entry->has_zero_child) | |
666 | superset_entry->has_zero_child = 1; | |
d4b60170 | 667 | |
2bf105ab RK |
668 | splay_tree_foreach (subset_entry->children, insert_subset_children, |
669 | superset_entry->children); | |
670 | } | |
3932261a | 671 | |
2bf105ab | 672 | /* Enter the SUBSET itself as a child of the SUPERSET. */ |
ca7fd9cd | 673 | splay_tree_insert (superset_entry->children, |
2bf105ab RK |
674 | (splay_tree_key) subset, 0); |
675 | } | |
3932261a MM |
676 | } |
677 | ||
a0c33338 RK |
678 | /* Record that component types of TYPE, if any, are part of that type for |
679 | aliasing purposes. For record types, we only record component types | |
680 | for fields that are marked addressable. For array types, we always | |
681 | record the component types, so the front end should not call this | |
682 | function if the individual component aren't addressable. */ | |
683 | ||
684 | void | |
685 | record_component_aliases (type) | |
686 | tree type; | |
687 | { | |
3bdf5ad1 | 688 | HOST_WIDE_INT superset = get_alias_set (type); |
a0c33338 RK |
689 | tree field; |
690 | ||
691 | if (superset == 0) | |
692 | return; | |
693 | ||
694 | switch (TREE_CODE (type)) | |
695 | { | |
696 | case ARRAY_TYPE: | |
2bf105ab RK |
697 | if (! TYPE_NONALIASED_COMPONENT (type)) |
698 | record_alias_subset (superset, get_alias_set (TREE_TYPE (type))); | |
a0c33338 RK |
699 | break; |
700 | ||
701 | case RECORD_TYPE: | |
702 | case UNION_TYPE: | |
703 | case QUAL_UNION_TYPE: | |
61eece67 DN |
704 | /* Recursively record aliases for the base classes, if there are any */ |
705 | if (TYPE_BINFO (type) != NULL && TYPE_BINFO_BASETYPES (type) != NULL) | |
ca7fd9cd KH |
706 | { |
707 | int i; | |
708 | for (i = 0; i < TREE_VEC_LENGTH (TYPE_BINFO_BASETYPES (type)); i++) | |
709 | { | |
710 | tree binfo = TREE_VEC_ELT (TYPE_BINFO_BASETYPES (type), i); | |
711 | record_alias_subset (superset, | |
61eece67 | 712 | get_alias_set (BINFO_TYPE (binfo))); |
ca7fd9cd KH |
713 | } |
714 | } | |
a0c33338 | 715 | for (field = TYPE_FIELDS (type); field != 0; field = TREE_CHAIN (field)) |
b16a49a1 | 716 | if (TREE_CODE (field) == FIELD_DECL && ! DECL_NONADDRESSABLE_P (field)) |
2bf105ab | 717 | record_alias_subset (superset, get_alias_set (TREE_TYPE (field))); |
a0c33338 RK |
718 | break; |
719 | ||
1d79fd2c JW |
720 | case COMPLEX_TYPE: |
721 | record_alias_subset (superset, get_alias_set (TREE_TYPE (type))); | |
722 | break; | |
723 | ||
a0c33338 RK |
724 | default: |
725 | break; | |
726 | } | |
727 | } | |
728 | ||
3bdf5ad1 RK |
729 | /* Allocate an alias set for use in storing and reading from the varargs |
730 | spill area. */ | |
731 | ||
732 | HOST_WIDE_INT | |
733 | get_varargs_alias_set () | |
734 | { | |
735 | static HOST_WIDE_INT set = -1; | |
736 | ||
737 | if (set == -1) | |
738 | set = new_alias_set (); | |
739 | ||
740 | return set; | |
741 | } | |
742 | ||
743 | /* Likewise, but used for the fixed portions of the frame, e.g., register | |
744 | save areas. */ | |
745 | ||
746 | HOST_WIDE_INT | |
747 | get_frame_alias_set () | |
748 | { | |
749 | static HOST_WIDE_INT set = -1; | |
750 | ||
751 | if (set == -1) | |
752 | set = new_alias_set (); | |
753 | ||
754 | return set; | |
755 | } | |
756 | ||
2a2c8203 JC |
757 | /* Inside SRC, the source of a SET, find a base address. */ |
758 | ||
9ae8ffe7 JL |
759 | static rtx |
760 | find_base_value (src) | |
b3694847 | 761 | rtx src; |
9ae8ffe7 | 762 | { |
713f41f9 | 763 | unsigned int regno; |
0aacc8ed | 764 | |
9ae8ffe7 JL |
765 | switch (GET_CODE (src)) |
766 | { | |
767 | case SYMBOL_REF: | |
768 | case LABEL_REF: | |
769 | return src; | |
770 | ||
771 | case REG: | |
fb6754f0 | 772 | regno = REGNO (src); |
d4b60170 | 773 | /* At the start of a function, argument registers have known base |
2a2c8203 JC |
774 | values which may be lost later. Returning an ADDRESS |
775 | expression here allows optimization based on argument values | |
776 | even when the argument registers are used for other purposes. */ | |
713f41f9 BS |
777 | if (regno < FIRST_PSEUDO_REGISTER && copying_arguments) |
778 | return new_reg_base_value[regno]; | |
73774bc7 | 779 | |
eaf407a5 | 780 | /* If a pseudo has a known base value, return it. Do not do this |
9b462c42 RH |
781 | for non-fixed hard regs since it can result in a circular |
782 | dependency chain for registers which have values at function entry. | |
eaf407a5 JL |
783 | |
784 | The test above is not sufficient because the scheduler may move | |
785 | a copy out of an arg reg past the NOTE_INSN_FUNCTION_BEGIN. */ | |
9b462c42 | 786 | if ((regno >= FIRST_PSEUDO_REGISTER || fixed_regs[regno]) |
83bbd9b6 RH |
787 | && regno < reg_base_value_size) |
788 | { | |
789 | /* If we're inside init_alias_analysis, use new_reg_base_value | |
790 | to reduce the number of relaxation iterations. */ | |
1afdf91c RH |
791 | if (new_reg_base_value && new_reg_base_value[regno] |
792 | && REG_N_SETS (regno) == 1) | |
83bbd9b6 RH |
793 | return new_reg_base_value[regno]; |
794 | ||
795 | if (reg_base_value[regno]) | |
796 | return reg_base_value[regno]; | |
797 | } | |
73774bc7 | 798 | |
9ae8ffe7 JL |
799 | return src; |
800 | ||
801 | case MEM: | |
802 | /* Check for an argument passed in memory. Only record in the | |
803 | copying-arguments block; it is too hard to track changes | |
804 | otherwise. */ | |
805 | if (copying_arguments | |
806 | && (XEXP (src, 0) == arg_pointer_rtx | |
807 | || (GET_CODE (XEXP (src, 0)) == PLUS | |
808 | && XEXP (XEXP (src, 0), 0) == arg_pointer_rtx))) | |
38a448ca | 809 | return gen_rtx_ADDRESS (VOIDmode, src); |
9ae8ffe7 JL |
810 | return 0; |
811 | ||
812 | case CONST: | |
813 | src = XEXP (src, 0); | |
814 | if (GET_CODE (src) != PLUS && GET_CODE (src) != MINUS) | |
815 | break; | |
d4b60170 | 816 | |
ec5c56db | 817 | /* ... fall through ... */ |
2a2c8203 | 818 | |
9ae8ffe7 JL |
819 | case PLUS: |
820 | case MINUS: | |
2a2c8203 | 821 | { |
ec907dd8 JL |
822 | rtx temp, src_0 = XEXP (src, 0), src_1 = XEXP (src, 1); |
823 | ||
0134bf2d DE |
824 | /* If either operand is a REG that is a known pointer, then it |
825 | is the base. */ | |
826 | if (REG_P (src_0) && REG_POINTER (src_0)) | |
827 | return find_base_value (src_0); | |
828 | if (REG_P (src_1) && REG_POINTER (src_1)) | |
829 | return find_base_value (src_1); | |
830 | ||
ec907dd8 JL |
831 | /* If either operand is a REG, then see if we already have |
832 | a known value for it. */ | |
0134bf2d | 833 | if (REG_P (src_0)) |
ec907dd8 JL |
834 | { |
835 | temp = find_base_value (src_0); | |
d4b60170 | 836 | if (temp != 0) |
ec907dd8 JL |
837 | src_0 = temp; |
838 | } | |
839 | ||
0134bf2d | 840 | if (REG_P (src_1)) |
ec907dd8 JL |
841 | { |
842 | temp = find_base_value (src_1); | |
d4b60170 | 843 | if (temp!= 0) |
ec907dd8 JL |
844 | src_1 = temp; |
845 | } | |
2a2c8203 | 846 | |
0134bf2d DE |
847 | /* If either base is named object or a special address |
848 | (like an argument or stack reference), then use it for the | |
849 | base term. */ | |
850 | if (src_0 != 0 | |
851 | && (GET_CODE (src_0) == SYMBOL_REF | |
852 | || GET_CODE (src_0) == LABEL_REF | |
853 | || (GET_CODE (src_0) == ADDRESS | |
854 | && GET_MODE (src_0) != VOIDmode))) | |
855 | return src_0; | |
856 | ||
857 | if (src_1 != 0 | |
858 | && (GET_CODE (src_1) == SYMBOL_REF | |
859 | || GET_CODE (src_1) == LABEL_REF | |
860 | || (GET_CODE (src_1) == ADDRESS | |
861 | && GET_MODE (src_1) != VOIDmode))) | |
862 | return src_1; | |
863 | ||
d4b60170 | 864 | /* Guess which operand is the base address: |
ec907dd8 JL |
865 | If either operand is a symbol, then it is the base. If |
866 | either operand is a CONST_INT, then the other is the base. */ | |
d4b60170 | 867 | if (GET_CODE (src_1) == CONST_INT || CONSTANT_P (src_0)) |
2a2c8203 | 868 | return find_base_value (src_0); |
d4b60170 | 869 | else if (GET_CODE (src_0) == CONST_INT || CONSTANT_P (src_1)) |
ec907dd8 JL |
870 | return find_base_value (src_1); |
871 | ||
9ae8ffe7 | 872 | return 0; |
2a2c8203 JC |
873 | } |
874 | ||
875 | case LO_SUM: | |
876 | /* The standard form is (lo_sum reg sym) so look only at the | |
877 | second operand. */ | |
878 | return find_base_value (XEXP (src, 1)); | |
9ae8ffe7 JL |
879 | |
880 | case AND: | |
881 | /* If the second operand is constant set the base | |
ec5c56db | 882 | address to the first operand. */ |
2a2c8203 JC |
883 | if (GET_CODE (XEXP (src, 1)) == CONST_INT && INTVAL (XEXP (src, 1)) != 0) |
884 | return find_base_value (XEXP (src, 0)); | |
9ae8ffe7 JL |
885 | return 0; |
886 | ||
61f0131c R |
887 | case TRUNCATE: |
888 | if (GET_MODE_SIZE (GET_MODE (src)) < GET_MODE_SIZE (Pmode)) | |
889 | break; | |
890 | /* Fall through. */ | |
9ae8ffe7 | 891 | case HIGH: |
d288e53d DE |
892 | case PRE_INC: |
893 | case PRE_DEC: | |
894 | case POST_INC: | |
895 | case POST_DEC: | |
896 | case PRE_MODIFY: | |
897 | case POST_MODIFY: | |
2a2c8203 | 898 | return find_base_value (XEXP (src, 0)); |
1d300e19 | 899 | |
0aacc8ed RK |
900 | case ZERO_EXTEND: |
901 | case SIGN_EXTEND: /* used for NT/Alpha pointers */ | |
902 | { | |
903 | rtx temp = find_base_value (XEXP (src, 0)); | |
904 | ||
905 | #ifdef POINTERS_EXTEND_UNSIGNED | |
906 | if (temp != 0 && CONSTANT_P (temp) && GET_MODE (temp) != Pmode) | |
907 | temp = convert_memory_address (Pmode, temp); | |
908 | #endif | |
909 | ||
910 | return temp; | |
911 | } | |
912 | ||
1d300e19 KG |
913 | default: |
914 | break; | |
9ae8ffe7 JL |
915 | } |
916 | ||
917 | return 0; | |
918 | } | |
919 | ||
920 | /* Called from init_alias_analysis indirectly through note_stores. */ | |
921 | ||
d4b60170 | 922 | /* While scanning insns to find base values, reg_seen[N] is nonzero if |
9ae8ffe7 JL |
923 | register N has been set in this function. */ |
924 | static char *reg_seen; | |
925 | ||
13309a5f JC |
926 | /* Addresses which are known not to alias anything else are identified |
927 | by a unique integer. */ | |
ec907dd8 JL |
928 | static int unique_id; |
929 | ||
2a2c8203 | 930 | static void |
84832317 | 931 | record_set (dest, set, data) |
9ae8ffe7 | 932 | rtx dest, set; |
84832317 | 933 | void *data ATTRIBUTE_UNUSED; |
9ae8ffe7 | 934 | { |
b3694847 | 935 | unsigned regno; |
9ae8ffe7 | 936 | rtx src; |
c28b4e40 | 937 | int n; |
9ae8ffe7 JL |
938 | |
939 | if (GET_CODE (dest) != REG) | |
940 | return; | |
941 | ||
fb6754f0 | 942 | regno = REGNO (dest); |
9ae8ffe7 | 943 | |
ac606739 GS |
944 | if (regno >= reg_base_value_size) |
945 | abort (); | |
946 | ||
c28b4e40 JW |
947 | /* If this spans multiple hard registers, then we must indicate that every |
948 | register has an unusable value. */ | |
949 | if (regno < FIRST_PSEUDO_REGISTER) | |
950 | n = HARD_REGNO_NREGS (regno, GET_MODE (dest)); | |
951 | else | |
952 | n = 1; | |
953 | if (n != 1) | |
954 | { | |
955 | while (--n >= 0) | |
956 | { | |
957 | reg_seen[regno + n] = 1; | |
958 | new_reg_base_value[regno + n] = 0; | |
959 | } | |
960 | return; | |
961 | } | |
962 | ||
9ae8ffe7 JL |
963 | if (set) |
964 | { | |
965 | /* A CLOBBER wipes out any old value but does not prevent a previously | |
966 | unset register from acquiring a base address (i.e. reg_seen is not | |
967 | set). */ | |
968 | if (GET_CODE (set) == CLOBBER) | |
969 | { | |
ec907dd8 | 970 | new_reg_base_value[regno] = 0; |
9ae8ffe7 JL |
971 | return; |
972 | } | |
973 | src = SET_SRC (set); | |
974 | } | |
975 | else | |
976 | { | |
9ae8ffe7 JL |
977 | if (reg_seen[regno]) |
978 | { | |
ec907dd8 | 979 | new_reg_base_value[regno] = 0; |
9ae8ffe7 JL |
980 | return; |
981 | } | |
982 | reg_seen[regno] = 1; | |
38a448ca RH |
983 | new_reg_base_value[regno] = gen_rtx_ADDRESS (Pmode, |
984 | GEN_INT (unique_id++)); | |
9ae8ffe7 JL |
985 | return; |
986 | } | |
987 | ||
988 | /* This is not the first set. If the new value is not related to the | |
989 | old value, forget the base value. Note that the following code is | |
990 | not detected: | |
991 | extern int x, y; int *p = &x; p += (&y-&x); | |
992 | ANSI C does not allow computing the difference of addresses | |
993 | of distinct top level objects. */ | |
ec907dd8 | 994 | if (new_reg_base_value[regno]) |
9ae8ffe7 JL |
995 | switch (GET_CODE (src)) |
996 | { | |
2a2c8203 | 997 | case LO_SUM: |
9ae8ffe7 JL |
998 | case MINUS: |
999 | if (XEXP (src, 0) != dest && XEXP (src, 1) != dest) | |
ec907dd8 | 1000 | new_reg_base_value[regno] = 0; |
9ae8ffe7 | 1001 | break; |
61f0131c R |
1002 | case PLUS: |
1003 | /* If the value we add in the PLUS is also a valid base value, | |
1004 | this might be the actual base value, and the original value | |
1005 | an index. */ | |
1006 | { | |
1007 | rtx other = NULL_RTX; | |
1008 | ||
1009 | if (XEXP (src, 0) == dest) | |
1010 | other = XEXP (src, 1); | |
1011 | else if (XEXP (src, 1) == dest) | |
1012 | other = XEXP (src, 0); | |
1013 | ||
1014 | if (! other || find_base_value (other)) | |
1015 | new_reg_base_value[regno] = 0; | |
1016 | break; | |
1017 | } | |
9ae8ffe7 JL |
1018 | case AND: |
1019 | if (XEXP (src, 0) != dest || GET_CODE (XEXP (src, 1)) != CONST_INT) | |
ec907dd8 | 1020 | new_reg_base_value[regno] = 0; |
9ae8ffe7 | 1021 | break; |
9ae8ffe7 | 1022 | default: |
ec907dd8 | 1023 | new_reg_base_value[regno] = 0; |
9ae8ffe7 JL |
1024 | break; |
1025 | } | |
1026 | /* If this is the first set of a register, record the value. */ | |
1027 | else if ((regno >= FIRST_PSEUDO_REGISTER || ! fixed_regs[regno]) | |
ec907dd8 JL |
1028 | && ! reg_seen[regno] && new_reg_base_value[regno] == 0) |
1029 | new_reg_base_value[regno] = find_base_value (src); | |
9ae8ffe7 JL |
1030 | |
1031 | reg_seen[regno] = 1; | |
1032 | } | |
1033 | ||
ac3d9668 RK |
1034 | /* Called from loop optimization when a new pseudo-register is |
1035 | created. It indicates that REGNO is being set to VAL. f INVARIANT | |
1036 | is true then this value also describes an invariant relationship | |
1037 | which can be used to deduce that two registers with unknown values | |
1038 | are different. */ | |
d4b60170 | 1039 | |
9ae8ffe7 | 1040 | void |
de12be17 | 1041 | record_base_value (regno, val, invariant) |
ac3d9668 | 1042 | unsigned int regno; |
9ae8ffe7 | 1043 | rtx val; |
de12be17 | 1044 | int invariant; |
9ae8ffe7 | 1045 | { |
ac3d9668 | 1046 | if (regno >= reg_base_value_size) |
9ae8ffe7 | 1047 | return; |
de12be17 | 1048 | |
de12be17 JC |
1049 | if (invariant && alias_invariant) |
1050 | alias_invariant[regno] = val; | |
1051 | ||
9ae8ffe7 JL |
1052 | if (GET_CODE (val) == REG) |
1053 | { | |
fb6754f0 BS |
1054 | if (REGNO (val) < reg_base_value_size) |
1055 | reg_base_value[regno] = reg_base_value[REGNO (val)]; | |
d4b60170 | 1056 | |
9ae8ffe7 JL |
1057 | return; |
1058 | } | |
d4b60170 | 1059 | |
9ae8ffe7 JL |
1060 | reg_base_value[regno] = find_base_value (val); |
1061 | } | |
1062 | ||
43fe47ca JW |
1063 | /* Clear alias info for a register. This is used if an RTL transformation |
1064 | changes the value of a register. This is used in flow by AUTO_INC_DEC | |
1065 | optimizations. We don't need to clear reg_base_value, since flow only | |
1066 | changes the offset. */ | |
1067 | ||
1068 | void | |
5197bd50 RK |
1069 | clear_reg_alias_info (reg) |
1070 | rtx reg; | |
43fe47ca | 1071 | { |
4e1a4144 JW |
1072 | unsigned int regno = REGNO (reg); |
1073 | ||
1074 | if (regno < reg_known_value_size && regno >= FIRST_PSEUDO_REGISTER) | |
1075 | reg_known_value[regno] = reg; | |
43fe47ca JW |
1076 | } |
1077 | ||
db048faf MM |
1078 | /* Returns a canonical version of X, from the point of view alias |
1079 | analysis. (For example, if X is a MEM whose address is a register, | |
1080 | and the register has a known value (say a SYMBOL_REF), then a MEM | |
1081 | whose address is the SYMBOL_REF is returned.) */ | |
1082 | ||
1083 | rtx | |
9ae8ffe7 JL |
1084 | canon_rtx (x) |
1085 | rtx x; | |
1086 | { | |
1087 | /* Recursively look for equivalences. */ | |
fb6754f0 BS |
1088 | if (GET_CODE (x) == REG && REGNO (x) >= FIRST_PSEUDO_REGISTER |
1089 | && REGNO (x) < reg_known_value_size) | |
1090 | return reg_known_value[REGNO (x)] == x | |
1091 | ? x : canon_rtx (reg_known_value[REGNO (x)]); | |
9ae8ffe7 JL |
1092 | else if (GET_CODE (x) == PLUS) |
1093 | { | |
1094 | rtx x0 = canon_rtx (XEXP (x, 0)); | |
1095 | rtx x1 = canon_rtx (XEXP (x, 1)); | |
1096 | ||
1097 | if (x0 != XEXP (x, 0) || x1 != XEXP (x, 1)) | |
1098 | { | |
9ae8ffe7 | 1099 | if (GET_CODE (x0) == CONST_INT) |
ed8908e7 | 1100 | return plus_constant (x1, INTVAL (x0)); |
9ae8ffe7 | 1101 | else if (GET_CODE (x1) == CONST_INT) |
ed8908e7 | 1102 | return plus_constant (x0, INTVAL (x1)); |
38a448ca | 1103 | return gen_rtx_PLUS (GET_MODE (x), x0, x1); |
9ae8ffe7 JL |
1104 | } |
1105 | } | |
d4b60170 | 1106 | |
9ae8ffe7 JL |
1107 | /* This gives us much better alias analysis when called from |
1108 | the loop optimizer. Note we want to leave the original | |
1109 | MEM alone, but need to return the canonicalized MEM with | |
1110 | all the flags with their original values. */ | |
1111 | else if (GET_CODE (x) == MEM) | |
f1ec5147 | 1112 | x = replace_equiv_address_nv (x, canon_rtx (XEXP (x, 0))); |
d4b60170 | 1113 | |
9ae8ffe7 JL |
1114 | return x; |
1115 | } | |
1116 | ||
1117 | /* Return 1 if X and Y are identical-looking rtx's. | |
1118 | ||
1119 | We use the data in reg_known_value above to see if two registers with | |
1120 | different numbers are, in fact, equivalent. */ | |
1121 | ||
1122 | static int | |
1123 | rtx_equal_for_memref_p (x, y) | |
1124 | rtx x, y; | |
1125 | { | |
b3694847 SS |
1126 | int i; |
1127 | int j; | |
1128 | enum rtx_code code; | |
1129 | const char *fmt; | |
9ae8ffe7 JL |
1130 | |
1131 | if (x == 0 && y == 0) | |
1132 | return 1; | |
1133 | if (x == 0 || y == 0) | |
1134 | return 0; | |
d4b60170 | 1135 | |
9ae8ffe7 JL |
1136 | x = canon_rtx (x); |
1137 | y = canon_rtx (y); | |
1138 | ||
1139 | if (x == y) | |
1140 | return 1; | |
1141 | ||
1142 | code = GET_CODE (x); | |
1143 | /* Rtx's of different codes cannot be equal. */ | |
1144 | if (code != GET_CODE (y)) | |
1145 | return 0; | |
1146 | ||
1147 | /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. | |
1148 | (REG:SI x) and (REG:HI x) are NOT equivalent. */ | |
1149 | ||
1150 | if (GET_MODE (x) != GET_MODE (y)) | |
1151 | return 0; | |
1152 | ||
db048faf MM |
1153 | /* Some RTL can be compared without a recursive examination. */ |
1154 | switch (code) | |
1155 | { | |
ab59db3c BS |
1156 | case VALUE: |
1157 | return CSELIB_VAL_PTR (x) == CSELIB_VAL_PTR (y); | |
1158 | ||
db048faf MM |
1159 | case REG: |
1160 | return REGNO (x) == REGNO (y); | |
1161 | ||
1162 | case LABEL_REF: | |
1163 | return XEXP (x, 0) == XEXP (y, 0); | |
ca7fd9cd | 1164 | |
db048faf MM |
1165 | case SYMBOL_REF: |
1166 | return XSTR (x, 0) == XSTR (y, 0); | |
1167 | ||
1168 | case CONST_INT: | |
1169 | case CONST_DOUBLE: | |
1170 | /* There's no need to compare the contents of CONST_DOUBLEs or | |
1171 | CONST_INTs because pointer equality is a good enough | |
1172 | comparison for these nodes. */ | |
1173 | return 0; | |
1174 | ||
1175 | case ADDRESSOF: | |
831ecbd4 RK |
1176 | return (XINT (x, 1) == XINT (y, 1) |
1177 | && rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 0))); | |
db048faf MM |
1178 | |
1179 | default: | |
1180 | break; | |
1181 | } | |
9ae8ffe7 JL |
1182 | |
1183 | /* For commutative operations, the RTX match if the operand match in any | |
1184 | order. Also handle the simple binary and unary cases without a loop. */ | |
1185 | if (code == EQ || code == NE || GET_RTX_CLASS (code) == 'c') | |
1186 | return ((rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 0)) | |
1187 | && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 1))) | |
1188 | || (rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 1)) | |
1189 | && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 0)))); | |
1190 | else if (GET_RTX_CLASS (code) == '<' || GET_RTX_CLASS (code) == '2') | |
1191 | return (rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 0)) | |
1192 | && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 1))); | |
1193 | else if (GET_RTX_CLASS (code) == '1') | |
1194 | return rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 0)); | |
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++) | |
d4b60170 RK |
1218 | if (rtx_equal_for_memref_p (XVECEXP (x, i, j), |
1219 | XVECEXP (y, i, j)) == 0) | |
9ae8ffe7 JL |
1220 | return 0; |
1221 | break; | |
1222 | ||
1223 | case 'e': | |
1224 | if (rtx_equal_for_memref_p (XEXP (x, i), XEXP (y, i)) == 0) | |
1225 | return 0; | |
1226 | break; | |
1227 | ||
3237ac18 AH |
1228 | /* This can happen for asm operands. */ |
1229 | case 's': | |
1230 | if (strcmp (XSTR (x, i), XSTR (y, i))) | |
1231 | return 0; | |
1232 | break; | |
1233 | ||
aee21ba9 JL |
1234 | /* This can happen for an asm which clobbers memory. */ |
1235 | case '0': | |
1236 | break; | |
1237 | ||
9ae8ffe7 JL |
1238 | /* It is believed that rtx's at this level will never |
1239 | contain anything but integers and other rtx's, | |
1240 | except for within LABEL_REFs and SYMBOL_REFs. */ | |
1241 | default: | |
1242 | abort (); | |
1243 | } | |
1244 | } | |
1245 | return 1; | |
1246 | } | |
1247 | ||
1248 | /* Given an rtx X, find a SYMBOL_REF or LABEL_REF within | |
1249 | X and return it, or return 0 if none found. */ | |
1250 | ||
1251 | static rtx | |
1252 | find_symbolic_term (x) | |
1253 | rtx x; | |
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 | ||
1282 | static rtx | |
1283 | find_base_term (x) | |
b3694847 | 1284 | rtx x; |
9ae8ffe7 | 1285 | { |
eab5c70a BS |
1286 | cselib_val *val; |
1287 | struct elt_loc_list *l; | |
1288 | ||
b949ea8b JW |
1289 | #if defined (FIND_BASE_TERM) |
1290 | /* Try machine-dependent ways to find the base term. */ | |
1291 | x = FIND_BASE_TERM (x); | |
1292 | #endif | |
1293 | ||
9ae8ffe7 JL |
1294 | switch (GET_CODE (x)) |
1295 | { | |
1296 | case REG: | |
1297 | return REG_BASE_VALUE (x); | |
1298 | ||
d288e53d DE |
1299 | case TRUNCATE: |
1300 | if (GET_MODE_SIZE (GET_MODE (x)) < GET_MODE_SIZE (Pmode)) | |
ca7fd9cd | 1301 | return 0; |
d288e53d | 1302 | /* Fall through. */ |
9ae8ffe7 | 1303 | case HIGH: |
6d849a2a JL |
1304 | case PRE_INC: |
1305 | case PRE_DEC: | |
1306 | case POST_INC: | |
1307 | case POST_DEC: | |
d288e53d DE |
1308 | case PRE_MODIFY: |
1309 | case POST_MODIFY: | |
6d849a2a JL |
1310 | return find_base_term (XEXP (x, 0)); |
1311 | ||
1abade85 RK |
1312 | case ZERO_EXTEND: |
1313 | case SIGN_EXTEND: /* Used for Alpha/NT pointers */ | |
1314 | { | |
1315 | rtx temp = find_base_term (XEXP (x, 0)); | |
1316 | ||
1317 | #ifdef POINTERS_EXTEND_UNSIGNED | |
1318 | if (temp != 0 && CONSTANT_P (temp) && GET_MODE (temp) != Pmode) | |
1319 | temp = convert_memory_address (Pmode, temp); | |
1320 | #endif | |
1321 | ||
1322 | return temp; | |
1323 | } | |
1324 | ||
eab5c70a BS |
1325 | case VALUE: |
1326 | val = CSELIB_VAL_PTR (x); | |
1327 | for (l = val->locs; l; l = l->next) | |
1328 | if ((x = find_base_term (l->loc)) != 0) | |
1329 | return x; | |
1330 | return 0; | |
1331 | ||
9ae8ffe7 JL |
1332 | case CONST: |
1333 | x = XEXP (x, 0); | |
1334 | if (GET_CODE (x) != PLUS && GET_CODE (x) != MINUS) | |
1335 | return 0; | |
1336 | /* fall through */ | |
1337 | case LO_SUM: | |
1338 | case PLUS: | |
1339 | case MINUS: | |
1340 | { | |
3c567fae JL |
1341 | rtx tmp1 = XEXP (x, 0); |
1342 | rtx tmp2 = XEXP (x, 1); | |
1343 | ||
f5143c46 | 1344 | /* This is a little bit tricky since we have to determine which of |
3c567fae JL |
1345 | the two operands represents the real base address. Otherwise this |
1346 | routine may return the index register instead of the base register. | |
1347 | ||
1348 | That may cause us to believe no aliasing was possible, when in | |
1349 | fact aliasing is possible. | |
1350 | ||
1351 | We use a few simple tests to guess the base register. Additional | |
1352 | tests can certainly be added. For example, if one of the operands | |
1353 | is a shift or multiply, then it must be the index register and the | |
1354 | other operand is the base register. */ | |
ca7fd9cd | 1355 | |
b949ea8b JW |
1356 | if (tmp1 == pic_offset_table_rtx && CONSTANT_P (tmp2)) |
1357 | return find_base_term (tmp2); | |
1358 | ||
3c567fae JL |
1359 | /* If either operand is known to be a pointer, then use it |
1360 | to determine the base term. */ | |
3502dc9c | 1361 | if (REG_P (tmp1) && REG_POINTER (tmp1)) |
3c567fae JL |
1362 | return find_base_term (tmp1); |
1363 | ||
3502dc9c | 1364 | if (REG_P (tmp2) && REG_POINTER (tmp2)) |
3c567fae JL |
1365 | return find_base_term (tmp2); |
1366 | ||
1367 | /* Neither operand was known to be a pointer. Go ahead and find the | |
1368 | base term for both operands. */ | |
1369 | tmp1 = find_base_term (tmp1); | |
1370 | tmp2 = find_base_term (tmp2); | |
1371 | ||
1372 | /* If either base term is named object or a special address | |
1373 | (like an argument or stack reference), then use it for the | |
1374 | base term. */ | |
d4b60170 | 1375 | if (tmp1 != 0 |
3c567fae JL |
1376 | && (GET_CODE (tmp1) == SYMBOL_REF |
1377 | || GET_CODE (tmp1) == LABEL_REF | |
1378 | || (GET_CODE (tmp1) == ADDRESS | |
1379 | && GET_MODE (tmp1) != VOIDmode))) | |
1380 | return tmp1; | |
1381 | ||
d4b60170 | 1382 | if (tmp2 != 0 |
3c567fae JL |
1383 | && (GET_CODE (tmp2) == SYMBOL_REF |
1384 | || GET_CODE (tmp2) == LABEL_REF | |
1385 | || (GET_CODE (tmp2) == ADDRESS | |
1386 | && GET_MODE (tmp2) != VOIDmode))) | |
1387 | return tmp2; | |
1388 | ||
1389 | /* We could not determine which of the two operands was the | |
1390 | base register and which was the index. So we can determine | |
1391 | nothing from the base alias check. */ | |
1392 | return 0; | |
9ae8ffe7 JL |
1393 | } |
1394 | ||
1395 | case AND: | |
d288e53d DE |
1396 | if (GET_CODE (XEXP (x, 1)) == CONST_INT && INTVAL (XEXP (x, 1)) != 0) |
1397 | return find_base_term (XEXP (x, 0)); | |
9ae8ffe7 JL |
1398 | return 0; |
1399 | ||
1400 | case SYMBOL_REF: | |
1401 | case LABEL_REF: | |
1402 | return x; | |
1403 | ||
d982e46e | 1404 | case ADDRESSOF: |
bb07060a | 1405 | return REG_BASE_VALUE (frame_pointer_rtx); |
d982e46e | 1406 | |
9ae8ffe7 JL |
1407 | default: |
1408 | return 0; | |
1409 | } | |
1410 | } | |
1411 | ||
1412 | /* Return 0 if the addresses X and Y are known to point to different | |
1413 | objects, 1 if they might be pointers to the same object. */ | |
1414 | ||
1415 | static int | |
56ee9281 | 1416 | base_alias_check (x, y, x_mode, y_mode) |
9ae8ffe7 | 1417 | rtx x, y; |
56ee9281 | 1418 | enum machine_mode x_mode, y_mode; |
9ae8ffe7 JL |
1419 | { |
1420 | rtx x_base = find_base_term (x); | |
1421 | rtx y_base = find_base_term (y); | |
1422 | ||
1c72c7f6 JC |
1423 | /* If the address itself has no known base see if a known equivalent |
1424 | value has one. If either address still has no known base, nothing | |
1425 | is known about aliasing. */ | |
1426 | if (x_base == 0) | |
1427 | { | |
1428 | rtx x_c; | |
d4b60170 | 1429 | |
1c72c7f6 JC |
1430 | if (! flag_expensive_optimizations || (x_c = canon_rtx (x)) == x) |
1431 | return 1; | |
d4b60170 | 1432 | |
1c72c7f6 JC |
1433 | x_base = find_base_term (x_c); |
1434 | if (x_base == 0) | |
1435 | return 1; | |
1436 | } | |
9ae8ffe7 | 1437 | |
1c72c7f6 JC |
1438 | if (y_base == 0) |
1439 | { | |
1440 | rtx y_c; | |
1441 | if (! flag_expensive_optimizations || (y_c = canon_rtx (y)) == y) | |
1442 | return 1; | |
d4b60170 | 1443 | |
1c72c7f6 JC |
1444 | y_base = find_base_term (y_c); |
1445 | if (y_base == 0) | |
1446 | return 1; | |
1447 | } | |
1448 | ||
1449 | /* If the base addresses are equal nothing is known about aliasing. */ | |
1450 | if (rtx_equal_p (x_base, y_base)) | |
9ae8ffe7 JL |
1451 | return 1; |
1452 | ||
ca7fd9cd | 1453 | /* The base addresses of the read and write are different expressions. |
56ee9281 RH |
1454 | If they are both symbols and they are not accessed via AND, there is |
1455 | no conflict. We can bring knowledge of object alignment into play | |
1456 | here. For example, on alpha, "char a, b;" can alias one another, | |
1457 | though "char a; long b;" cannot. */ | |
9ae8ffe7 | 1458 | if (GET_CODE (x_base) != ADDRESS && GET_CODE (y_base) != ADDRESS) |
c02f035f | 1459 | { |
56ee9281 RH |
1460 | if (GET_CODE (x) == AND && GET_CODE (y) == AND) |
1461 | return 1; | |
1462 | if (GET_CODE (x) == AND | |
1463 | && (GET_CODE (XEXP (x, 1)) != CONST_INT | |
8fa2140d | 1464 | || (int) GET_MODE_UNIT_SIZE (y_mode) < -INTVAL (XEXP (x, 1)))) |
56ee9281 RH |
1465 | return 1; |
1466 | if (GET_CODE (y) == AND | |
1467 | && (GET_CODE (XEXP (y, 1)) != CONST_INT | |
8fa2140d | 1468 | || (int) GET_MODE_UNIT_SIZE (x_mode) < -INTVAL (XEXP (y, 1)))) |
56ee9281 | 1469 | return 1; |
b2972551 JL |
1470 | /* Differing symbols never alias. */ |
1471 | return 0; | |
c02f035f | 1472 | } |
9ae8ffe7 JL |
1473 | |
1474 | /* If one address is a stack reference there can be no alias: | |
1475 | stack references using different base registers do not alias, | |
1476 | a stack reference can not alias a parameter, and a stack reference | |
1477 | can not alias a global. */ | |
1478 | if ((GET_CODE (x_base) == ADDRESS && GET_MODE (x_base) == Pmode) | |
1479 | || (GET_CODE (y_base) == ADDRESS && GET_MODE (y_base) == Pmode)) | |
1480 | return 0; | |
1481 | ||
1482 | if (! flag_argument_noalias) | |
1483 | return 1; | |
1484 | ||
1485 | if (flag_argument_noalias > 1) | |
1486 | return 0; | |
1487 | ||
ec5c56db | 1488 | /* Weak noalias assertion (arguments are distinct, but may match globals). */ |
9ae8ffe7 JL |
1489 | return ! (GET_MODE (x_base) == VOIDmode && GET_MODE (y_base) == VOIDmode); |
1490 | } | |
1491 | ||
eab5c70a BS |
1492 | /* Convert the address X into something we can use. This is done by returning |
1493 | it unchanged unless it is a value; in the latter case we call cselib to get | |
1494 | a more useful rtx. */ | |
3bdf5ad1 | 1495 | |
a13d4ebf | 1496 | rtx |
eab5c70a BS |
1497 | get_addr (x) |
1498 | rtx x; | |
1499 | { | |
1500 | cselib_val *v; | |
1501 | struct elt_loc_list *l; | |
1502 | ||
1503 | if (GET_CODE (x) != VALUE) | |
1504 | return x; | |
1505 | v = CSELIB_VAL_PTR (x); | |
1506 | for (l = v->locs; l; l = l->next) | |
1507 | if (CONSTANT_P (l->loc)) | |
1508 | return l->loc; | |
1509 | for (l = v->locs; l; l = l->next) | |
1510 | if (GET_CODE (l->loc) != REG && GET_CODE (l->loc) != MEM) | |
1511 | return l->loc; | |
1512 | if (v->locs) | |
1513 | return v->locs->loc; | |
1514 | return x; | |
1515 | } | |
1516 | ||
39cec1ac MH |
1517 | /* Return the address of the (N_REFS + 1)th memory reference to ADDR |
1518 | where SIZE is the size in bytes of the memory reference. If ADDR | |
1519 | is not modified by the memory reference then ADDR is returned. */ | |
1520 | ||
1521 | rtx | |
1522 | addr_side_effect_eval (addr, size, n_refs) | |
1523 | rtx addr; | |
1524 | int size; | |
1525 | int n_refs; | |
1526 | { | |
1527 | int offset = 0; | |
ca7fd9cd | 1528 | |
39cec1ac MH |
1529 | switch (GET_CODE (addr)) |
1530 | { | |
1531 | case PRE_INC: | |
1532 | offset = (n_refs + 1) * size; | |
1533 | break; | |
1534 | case PRE_DEC: | |
1535 | offset = -(n_refs + 1) * size; | |
1536 | break; | |
1537 | case POST_INC: | |
1538 | offset = n_refs * size; | |
1539 | break; | |
1540 | case POST_DEC: | |
1541 | offset = -n_refs * size; | |
1542 | break; | |
1543 | ||
1544 | default: | |
1545 | return addr; | |
1546 | } | |
ca7fd9cd | 1547 | |
39cec1ac MH |
1548 | if (offset) |
1549 | addr = gen_rtx_PLUS (GET_MODE (addr), XEXP (addr, 0), GEN_INT (offset)); | |
1550 | else | |
1551 | addr = XEXP (addr, 0); | |
1552 | ||
1553 | return addr; | |
1554 | } | |
1555 | ||
9ae8ffe7 JL |
1556 | /* Return nonzero if X and Y (memory addresses) could reference the |
1557 | same location in memory. C is an offset accumulator. When | |
1558 | C is nonzero, we are testing aliases between X and Y + C. | |
1559 | XSIZE is the size in bytes of the X reference, | |
1560 | similarly YSIZE is the size in bytes for Y. | |
1561 | ||
1562 | If XSIZE or YSIZE is zero, we do not know the amount of memory being | |
1563 | referenced (the reference was BLKmode), so make the most pessimistic | |
1564 | assumptions. | |
1565 | ||
c02f035f RH |
1566 | If XSIZE or YSIZE is negative, we may access memory outside the object |
1567 | being referenced as a side effect. This can happen when using AND to | |
1568 | align memory references, as is done on the Alpha. | |
1569 | ||
9ae8ffe7 | 1570 | Nice to notice that varying addresses cannot conflict with fp if no |
0211b6ab | 1571 | local variables had their addresses taken, but that's too hard now. */ |
9ae8ffe7 | 1572 | |
9ae8ffe7 JL |
1573 | static int |
1574 | memrefs_conflict_p (xsize, x, ysize, y, c) | |
b3694847 | 1575 | rtx x, y; |
9ae8ffe7 JL |
1576 | int xsize, ysize; |
1577 | HOST_WIDE_INT c; | |
1578 | { | |
eab5c70a BS |
1579 | if (GET_CODE (x) == VALUE) |
1580 | x = get_addr (x); | |
1581 | if (GET_CODE (y) == VALUE) | |
1582 | y = get_addr (y); | |
9ae8ffe7 JL |
1583 | if (GET_CODE (x) == HIGH) |
1584 | x = XEXP (x, 0); | |
1585 | else if (GET_CODE (x) == LO_SUM) | |
1586 | x = XEXP (x, 1); | |
1587 | else | |
39cec1ac | 1588 | x = canon_rtx (addr_side_effect_eval (x, xsize, 0)); |
9ae8ffe7 JL |
1589 | if (GET_CODE (y) == HIGH) |
1590 | y = XEXP (y, 0); | |
1591 | else if (GET_CODE (y) == LO_SUM) | |
1592 | y = XEXP (y, 1); | |
1593 | else | |
39cec1ac | 1594 | y = canon_rtx (addr_side_effect_eval (y, ysize, 0)); |
9ae8ffe7 JL |
1595 | |
1596 | if (rtx_equal_for_memref_p (x, y)) | |
1597 | { | |
c02f035f | 1598 | if (xsize <= 0 || ysize <= 0) |
9ae8ffe7 JL |
1599 | return 1; |
1600 | if (c >= 0 && xsize > c) | |
1601 | return 1; | |
1602 | if (c < 0 && ysize+c > 0) | |
1603 | return 1; | |
1604 | return 0; | |
1605 | } | |
1606 | ||
6e73e666 JC |
1607 | /* This code used to check for conflicts involving stack references and |
1608 | globals but the base address alias code now handles these cases. */ | |
9ae8ffe7 JL |
1609 | |
1610 | if (GET_CODE (x) == PLUS) | |
1611 | { | |
1612 | /* The fact that X is canonicalized means that this | |
1613 | PLUS rtx is canonicalized. */ | |
1614 | rtx x0 = XEXP (x, 0); | |
1615 | rtx x1 = XEXP (x, 1); | |
1616 | ||
1617 | if (GET_CODE (y) == PLUS) | |
1618 | { | |
1619 | /* The fact that Y is canonicalized means that this | |
1620 | PLUS rtx is canonicalized. */ | |
1621 | rtx y0 = XEXP (y, 0); | |
1622 | rtx y1 = XEXP (y, 1); | |
1623 | ||
1624 | if (rtx_equal_for_memref_p (x1, y1)) | |
1625 | return memrefs_conflict_p (xsize, x0, ysize, y0, c); | |
1626 | if (rtx_equal_for_memref_p (x0, y0)) | |
1627 | return memrefs_conflict_p (xsize, x1, ysize, y1, c); | |
1628 | if (GET_CODE (x1) == CONST_INT) | |
63be02db JM |
1629 | { |
1630 | if (GET_CODE (y1) == CONST_INT) | |
1631 | return memrefs_conflict_p (xsize, x0, ysize, y0, | |
1632 | c - INTVAL (x1) + INTVAL (y1)); | |
1633 | else | |
1634 | return memrefs_conflict_p (xsize, x0, ysize, y, | |
1635 | c - INTVAL (x1)); | |
1636 | } | |
9ae8ffe7 JL |
1637 | else if (GET_CODE (y1) == CONST_INT) |
1638 | return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1)); | |
1639 | ||
6e73e666 | 1640 | return 1; |
9ae8ffe7 JL |
1641 | } |
1642 | else if (GET_CODE (x1) == CONST_INT) | |
1643 | return memrefs_conflict_p (xsize, x0, ysize, y, c - INTVAL (x1)); | |
1644 | } | |
1645 | else if (GET_CODE (y) == PLUS) | |
1646 | { | |
1647 | /* The fact that Y is canonicalized means that this | |
1648 | PLUS rtx is canonicalized. */ | |
1649 | rtx y0 = XEXP (y, 0); | |
1650 | rtx y1 = XEXP (y, 1); | |
1651 | ||
1652 | if (GET_CODE (y1) == CONST_INT) | |
1653 | return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1)); | |
1654 | else | |
1655 | return 1; | |
1656 | } | |
1657 | ||
1658 | if (GET_CODE (x) == GET_CODE (y)) | |
1659 | switch (GET_CODE (x)) | |
1660 | { | |
1661 | case MULT: | |
1662 | { | |
1663 | /* Handle cases where we expect the second operands to be the | |
1664 | same, and check only whether the first operand would conflict | |
1665 | or not. */ | |
1666 | rtx x0, y0; | |
1667 | rtx x1 = canon_rtx (XEXP (x, 1)); | |
1668 | rtx y1 = canon_rtx (XEXP (y, 1)); | |
1669 | if (! rtx_equal_for_memref_p (x1, y1)) | |
1670 | return 1; | |
1671 | x0 = canon_rtx (XEXP (x, 0)); | |
1672 | y0 = canon_rtx (XEXP (y, 0)); | |
1673 | if (rtx_equal_for_memref_p (x0, y0)) | |
1674 | return (xsize == 0 || ysize == 0 | |
1675 | || (c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)); | |
1676 | ||
1677 | /* Can't properly adjust our sizes. */ | |
1678 | if (GET_CODE (x1) != CONST_INT) | |
1679 | return 1; | |
1680 | xsize /= INTVAL (x1); | |
1681 | ysize /= INTVAL (x1); | |
1682 | c /= INTVAL (x1); | |
1683 | return memrefs_conflict_p (xsize, x0, ysize, y0, c); | |
1684 | } | |
1d300e19 | 1685 | |
de12be17 JC |
1686 | case REG: |
1687 | /* Are these registers known not to be equal? */ | |
1688 | if (alias_invariant) | |
1689 | { | |
e51712db | 1690 | unsigned int r_x = REGNO (x), r_y = REGNO (y); |
de12be17 JC |
1691 | rtx i_x, i_y; /* invariant relationships of X and Y */ |
1692 | ||
1693 | i_x = r_x >= reg_base_value_size ? 0 : alias_invariant[r_x]; | |
1694 | i_y = r_y >= reg_base_value_size ? 0 : alias_invariant[r_y]; | |
1695 | ||
1696 | if (i_x == 0 && i_y == 0) | |
1697 | break; | |
1698 | ||
1699 | if (! memrefs_conflict_p (xsize, i_x ? i_x : x, | |
1700 | ysize, i_y ? i_y : y, c)) | |
1701 | return 0; | |
1702 | } | |
1703 | break; | |
1704 | ||
1d300e19 KG |
1705 | default: |
1706 | break; | |
9ae8ffe7 JL |
1707 | } |
1708 | ||
1709 | /* Treat an access through an AND (e.g. a subword access on an Alpha) | |
ca7fd9cd | 1710 | as an access with indeterminate size. Assume that references |
56ee9281 RH |
1711 | besides AND are aligned, so if the size of the other reference is |
1712 | at least as large as the alignment, assume no other overlap. */ | |
9ae8ffe7 | 1713 | if (GET_CODE (x) == AND && GET_CODE (XEXP (x, 1)) == CONST_INT) |
56ee9281 | 1714 | { |
02e3377d | 1715 | if (GET_CODE (y) == AND || ysize < -INTVAL (XEXP (x, 1))) |
56ee9281 RH |
1716 | xsize = -1; |
1717 | return memrefs_conflict_p (xsize, XEXP (x, 0), ysize, y, c); | |
1718 | } | |
9ae8ffe7 | 1719 | if (GET_CODE (y) == AND && GET_CODE (XEXP (y, 1)) == CONST_INT) |
c02f035f | 1720 | { |
56ee9281 | 1721 | /* ??? If we are indexing far enough into the array/structure, we |
ca7fd9cd | 1722 | may yet be able to determine that we can not overlap. But we |
c02f035f | 1723 | also need to that we are far enough from the end not to overlap |
56ee9281 | 1724 | a following reference, so we do nothing with that for now. */ |
02e3377d | 1725 | if (GET_CODE (x) == AND || xsize < -INTVAL (XEXP (y, 1))) |
56ee9281 RH |
1726 | ysize = -1; |
1727 | return memrefs_conflict_p (xsize, x, ysize, XEXP (y, 0), c); | |
c02f035f | 1728 | } |
9ae8ffe7 | 1729 | |
b24ea077 JW |
1730 | if (GET_CODE (x) == ADDRESSOF) |
1731 | { | |
1732 | if (y == frame_pointer_rtx | |
1733 | || GET_CODE (y) == ADDRESSOF) | |
1734 | return xsize <= 0 || ysize <= 0; | |
1735 | } | |
1736 | if (GET_CODE (y) == ADDRESSOF) | |
1737 | { | |
1738 | if (x == frame_pointer_rtx) | |
1739 | return xsize <= 0 || ysize <= 0; | |
1740 | } | |
d982e46e | 1741 | |
9ae8ffe7 JL |
1742 | if (CONSTANT_P (x)) |
1743 | { | |
1744 | if (GET_CODE (x) == CONST_INT && GET_CODE (y) == CONST_INT) | |
1745 | { | |
1746 | c += (INTVAL (y) - INTVAL (x)); | |
c02f035f | 1747 | return (xsize <= 0 || ysize <= 0 |
9ae8ffe7 JL |
1748 | || (c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)); |
1749 | } | |
1750 | ||
1751 | if (GET_CODE (x) == CONST) | |
1752 | { | |
1753 | if (GET_CODE (y) == CONST) | |
1754 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), | |
1755 | ysize, canon_rtx (XEXP (y, 0)), c); | |
1756 | else | |
1757 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), | |
1758 | ysize, y, c); | |
1759 | } | |
1760 | if (GET_CODE (y) == CONST) | |
1761 | return memrefs_conflict_p (xsize, x, ysize, | |
1762 | canon_rtx (XEXP (y, 0)), c); | |
1763 | ||
1764 | if (CONSTANT_P (y)) | |
b949ea8b | 1765 | return (xsize <= 0 || ysize <= 0 |
c02f035f | 1766 | || (rtx_equal_for_memref_p (x, y) |
b949ea8b | 1767 | && ((c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)))); |
9ae8ffe7 JL |
1768 | |
1769 | return 1; | |
1770 | } | |
1771 | return 1; | |
1772 | } | |
1773 | ||
1774 | /* Functions to compute memory dependencies. | |
1775 | ||
1776 | Since we process the insns in execution order, we can build tables | |
1777 | to keep track of what registers are fixed (and not aliased), what registers | |
1778 | are varying in known ways, and what registers are varying in unknown | |
1779 | ways. | |
1780 | ||
1781 | If both memory references are volatile, then there must always be a | |
1782 | dependence between the two references, since their order can not be | |
1783 | changed. A volatile and non-volatile reference can be interchanged | |
ca7fd9cd | 1784 | though. |
9ae8ffe7 | 1785 | |
dc1618bc RK |
1786 | A MEM_IN_STRUCT reference at a non-AND varying address can never |
1787 | conflict with a non-MEM_IN_STRUCT reference at a fixed address. We | |
1788 | also must allow AND addresses, because they may generate accesses | |
1789 | outside the object being referenced. This is used to generate | |
1790 | aligned addresses from unaligned addresses, for instance, the alpha | |
1791 | storeqi_unaligned pattern. */ | |
9ae8ffe7 JL |
1792 | |
1793 | /* Read dependence: X is read after read in MEM takes place. There can | |
1794 | only be a dependence here if both reads are volatile. */ | |
1795 | ||
1796 | int | |
1797 | read_dependence (mem, x) | |
1798 | rtx mem; | |
1799 | rtx x; | |
1800 | { | |
1801 | return MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem); | |
1802 | } | |
1803 | ||
c6df88cb MM |
1804 | /* Returns MEM1 if and only if MEM1 is a scalar at a fixed address and |
1805 | MEM2 is a reference to a structure at a varying address, or returns | |
1806 | MEM2 if vice versa. Otherwise, returns NULL_RTX. If a non-NULL | |
1807 | value is returned MEM1 and MEM2 can never alias. VARIES_P is used | |
1808 | to decide whether or not an address may vary; it should return | |
eab5c70a BS |
1809 | nonzero whenever variation is possible. |
1810 | MEM1_ADDR and MEM2_ADDR are the addresses of MEM1 and MEM2. */ | |
ca7fd9cd | 1811 | |
2c72b78f | 1812 | static rtx |
eab5c70a BS |
1813 | fixed_scalar_and_varying_struct_p (mem1, mem2, mem1_addr, mem2_addr, varies_p) |
1814 | rtx mem1, mem2; | |
1815 | rtx mem1_addr, mem2_addr; | |
e38fe8e0 | 1816 | int (*varies_p) PARAMS ((rtx, int)); |
ca7fd9cd | 1817 | { |
3e0abe15 GK |
1818 | if (! flag_strict_aliasing) |
1819 | return NULL_RTX; | |
1820 | ||
ca7fd9cd | 1821 | if (MEM_SCALAR_P (mem1) && MEM_IN_STRUCT_P (mem2) |
e38fe8e0 | 1822 | && !varies_p (mem1_addr, 1) && varies_p (mem2_addr, 1)) |
c6df88cb MM |
1823 | /* MEM1 is a scalar at a fixed address; MEM2 is a struct at a |
1824 | varying address. */ | |
1825 | return mem1; | |
1826 | ||
ca7fd9cd | 1827 | if (MEM_IN_STRUCT_P (mem1) && MEM_SCALAR_P (mem2) |
e38fe8e0 | 1828 | && varies_p (mem1_addr, 1) && !varies_p (mem2_addr, 1)) |
c6df88cb MM |
1829 | /* MEM2 is a scalar at a fixed address; MEM1 is a struct at a |
1830 | varying address. */ | |
1831 | return mem2; | |
1832 | ||
1833 | return NULL_RTX; | |
1834 | } | |
1835 | ||
1836 | /* Returns nonzero if something about the mode or address format MEM1 | |
1837 | indicates that it might well alias *anything*. */ | |
1838 | ||
2c72b78f | 1839 | static int |
c6df88cb MM |
1840 | aliases_everything_p (mem) |
1841 | rtx mem; | |
1842 | { | |
c6df88cb MM |
1843 | if (GET_CODE (XEXP (mem, 0)) == AND) |
1844 | /* If the address is an AND, its very hard to know at what it is | |
1845 | actually pointing. */ | |
1846 | return 1; | |
ca7fd9cd | 1847 | |
c6df88cb MM |
1848 | return 0; |
1849 | } | |
1850 | ||
998d7deb RH |
1851 | /* Return true if we can determine that the fields referenced cannot |
1852 | overlap for any pair of objects. */ | |
1853 | ||
1854 | static bool | |
1855 | nonoverlapping_component_refs_p (x, y) | |
1856 | tree x, y; | |
1857 | { | |
1858 | tree fieldx, fieldy, typex, typey, orig_y; | |
1859 | ||
1860 | do | |
1861 | { | |
1862 | /* The comparison has to be done at a common type, since we don't | |
d6a7951f | 1863 | know how the inheritance hierarchy works. */ |
998d7deb RH |
1864 | orig_y = y; |
1865 | do | |
1866 | { | |
1867 | fieldx = TREE_OPERAND (x, 1); | |
1868 | typex = DECL_FIELD_CONTEXT (fieldx); | |
1869 | ||
1870 | y = orig_y; | |
1871 | do | |
1872 | { | |
1873 | fieldy = TREE_OPERAND (y, 1); | |
1874 | typey = DECL_FIELD_CONTEXT (fieldy); | |
1875 | ||
1876 | if (typex == typey) | |
1877 | goto found; | |
1878 | ||
1879 | y = TREE_OPERAND (y, 0); | |
1880 | } | |
1881 | while (y && TREE_CODE (y) == COMPONENT_REF); | |
1882 | ||
1883 | x = TREE_OPERAND (x, 0); | |
1884 | } | |
1885 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
1886 | ||
1887 | /* Never found a common type. */ | |
1888 | return false; | |
1889 | ||
1890 | found: | |
1891 | /* If we're left with accessing different fields of a structure, | |
1892 | then no overlap. */ | |
1893 | if (TREE_CODE (typex) == RECORD_TYPE | |
1894 | && fieldx != fieldy) | |
1895 | return true; | |
1896 | ||
1897 | /* The comparison on the current field failed. If we're accessing | |
1898 | a very nested structure, look at the next outer level. */ | |
1899 | x = TREE_OPERAND (x, 0); | |
1900 | y = TREE_OPERAND (y, 0); | |
1901 | } | |
1902 | while (x && y | |
1903 | && TREE_CODE (x) == COMPONENT_REF | |
1904 | && TREE_CODE (y) == COMPONENT_REF); | |
ca7fd9cd | 1905 | |
998d7deb RH |
1906 | return false; |
1907 | } | |
1908 | ||
1909 | /* Look at the bottom of the COMPONENT_REF list for a DECL, and return it. */ | |
1910 | ||
1911 | static tree | |
1912 | decl_for_component_ref (x) | |
1913 | tree x; | |
1914 | { | |
1915 | do | |
1916 | { | |
1917 | x = TREE_OPERAND (x, 0); | |
1918 | } | |
1919 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
1920 | ||
1921 | return x && DECL_P (x) ? x : NULL_TREE; | |
1922 | } | |
1923 | ||
1924 | /* Walk up the COMPONENT_REF list and adjust OFFSET to compensate for the | |
1925 | offset of the field reference. */ | |
1926 | ||
1927 | static rtx | |
1928 | adjust_offset_for_component_ref (x, offset) | |
1929 | tree x; | |
1930 | rtx offset; | |
1931 | { | |
1932 | HOST_WIDE_INT ioffset; | |
1933 | ||
1934 | if (! offset) | |
1935 | return NULL_RTX; | |
1936 | ||
1937 | ioffset = INTVAL (offset); | |
ca7fd9cd | 1938 | do |
998d7deb RH |
1939 | { |
1940 | tree field = TREE_OPERAND (x, 1); | |
1941 | ||
1942 | if (! host_integerp (DECL_FIELD_OFFSET (field), 1)) | |
1943 | return NULL_RTX; | |
1944 | ioffset += (tree_low_cst (DECL_FIELD_OFFSET (field), 1) | |
1945 | + (tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1) | |
1946 | / BITS_PER_UNIT)); | |
1947 | ||
1948 | x = TREE_OPERAND (x, 0); | |
1949 | } | |
1950 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
1951 | ||
1952 | return GEN_INT (ioffset); | |
1953 | } | |
1954 | ||
1955 | /* Return nonzero if we can deterimine the exprs corresponding to memrefs | |
a4311dfe RK |
1956 | X and Y and they do not overlap. */ |
1957 | ||
1958 | static int | |
1959 | nonoverlapping_memrefs_p (x, y) | |
1960 | rtx x, y; | |
1961 | { | |
998d7deb | 1962 | tree exprx = MEM_EXPR (x), expry = MEM_EXPR (y); |
a4311dfe RK |
1963 | rtx rtlx, rtly; |
1964 | rtx basex, basey; | |
998d7deb | 1965 | rtx moffsetx, moffsety; |
a4311dfe RK |
1966 | HOST_WIDE_INT offsetx = 0, offsety = 0, sizex, sizey, tem; |
1967 | ||
998d7deb RH |
1968 | /* Unless both have exprs, we can't tell anything. */ |
1969 | if (exprx == 0 || expry == 0) | |
1970 | return 0; | |
1971 | ||
1972 | /* If both are field references, we may be able to determine something. */ | |
1973 | if (TREE_CODE (exprx) == COMPONENT_REF | |
1974 | && TREE_CODE (expry) == COMPONENT_REF | |
1975 | && nonoverlapping_component_refs_p (exprx, expry)) | |
1976 | return 1; | |
1977 | ||
1978 | /* If the field reference test failed, look at the DECLs involved. */ | |
1979 | moffsetx = MEM_OFFSET (x); | |
1980 | if (TREE_CODE (exprx) == COMPONENT_REF) | |
1981 | { | |
1982 | tree t = decl_for_component_ref (exprx); | |
1983 | if (! t) | |
1984 | return 0; | |
1985 | moffsetx = adjust_offset_for_component_ref (exprx, moffsetx); | |
1986 | exprx = t; | |
1987 | } | |
c67a1cf6 RH |
1988 | else if (TREE_CODE (exprx) == INDIRECT_REF) |
1989 | { | |
1990 | exprx = TREE_OPERAND (exprx, 0); | |
1991 | if (flag_argument_noalias < 2 | |
1992 | || TREE_CODE (exprx) != PARM_DECL) | |
1993 | return 0; | |
1994 | } | |
1995 | ||
998d7deb RH |
1996 | moffsety = MEM_OFFSET (y); |
1997 | if (TREE_CODE (expry) == COMPONENT_REF) | |
1998 | { | |
1999 | tree t = decl_for_component_ref (expry); | |
2000 | if (! t) | |
2001 | return 0; | |
2002 | moffsety = adjust_offset_for_component_ref (expry, moffsety); | |
2003 | expry = t; | |
2004 | } | |
c67a1cf6 RH |
2005 | else if (TREE_CODE (expry) == INDIRECT_REF) |
2006 | { | |
2007 | expry = TREE_OPERAND (expry, 0); | |
2008 | if (flag_argument_noalias < 2 | |
2009 | || TREE_CODE (expry) != PARM_DECL) | |
2010 | return 0; | |
2011 | } | |
998d7deb RH |
2012 | |
2013 | if (! DECL_P (exprx) || ! DECL_P (expry)) | |
a4311dfe RK |
2014 | return 0; |
2015 | ||
998d7deb RH |
2016 | rtlx = DECL_RTL (exprx); |
2017 | rtly = DECL_RTL (expry); | |
a4311dfe | 2018 | |
1edcd60b RK |
2019 | /* If either RTL is not a MEM, it must be a REG or CONCAT, meaning they |
2020 | can't overlap unless they are the same because we never reuse that part | |
2021 | of the stack frame used for locals for spilled pseudos. */ | |
2022 | if ((GET_CODE (rtlx) != MEM || GET_CODE (rtly) != MEM) | |
2023 | && ! rtx_equal_p (rtlx, rtly)) | |
a4311dfe RK |
2024 | return 1; |
2025 | ||
2026 | /* Get the base and offsets of both decls. If either is a register, we | |
2027 | know both are and are the same, so use that as the base. The only | |
2028 | we can avoid overlap is if we can deduce that they are nonoverlapping | |
2029 | pieces of that decl, which is very rare. */ | |
1edcd60b | 2030 | basex = GET_CODE (rtlx) == MEM ? XEXP (rtlx, 0) : rtlx; |
a4311dfe RK |
2031 | if (GET_CODE (basex) == PLUS && GET_CODE (XEXP (basex, 1)) == CONST_INT) |
2032 | offsetx = INTVAL (XEXP (basex, 1)), basex = XEXP (basex, 0); | |
2033 | ||
1edcd60b | 2034 | basey = GET_CODE (rtly) == MEM ? XEXP (rtly, 0) : rtly; |
a4311dfe RK |
2035 | if (GET_CODE (basey) == PLUS && GET_CODE (XEXP (basey, 1)) == CONST_INT) |
2036 | offsety = INTVAL (XEXP (basey, 1)), basey = XEXP (basey, 0); | |
2037 | ||
d746694a | 2038 | /* If the bases are different, we know they do not overlap if both |
ca7fd9cd | 2039 | are constants or if one is a constant and the other a pointer into the |
d746694a RK |
2040 | stack frame. Otherwise a different base means we can't tell if they |
2041 | overlap or not. */ | |
2042 | if (! rtx_equal_p (basex, basey)) | |
ca7fd9cd KH |
2043 | return ((CONSTANT_P (basex) && CONSTANT_P (basey)) |
2044 | || (CONSTANT_P (basex) && REG_P (basey) | |
2045 | && REGNO_PTR_FRAME_P (REGNO (basey))) | |
2046 | || (CONSTANT_P (basey) && REG_P (basex) | |
2047 | && REGNO_PTR_FRAME_P (REGNO (basex)))); | |
a4311dfe | 2048 | |
998d7deb | 2049 | sizex = (GET_CODE (rtlx) != MEM ? (int) GET_MODE_SIZE (GET_MODE (rtlx)) |
a4311dfe RK |
2050 | : MEM_SIZE (rtlx) ? INTVAL (MEM_SIZE (rtlx)) |
2051 | : -1); | |
998d7deb | 2052 | sizey = (GET_CODE (rtly) != MEM ? (int) GET_MODE_SIZE (GET_MODE (rtly)) |
a4311dfe RK |
2053 | : MEM_SIZE (rtly) ? INTVAL (MEM_SIZE (rtly)) : |
2054 | -1); | |
2055 | ||
0af5bc3e RK |
2056 | /* If we have an offset for either memref, it can update the values computed |
2057 | above. */ | |
998d7deb RH |
2058 | if (moffsetx) |
2059 | offsetx += INTVAL (moffsetx), sizex -= INTVAL (moffsetx); | |
2060 | if (moffsety) | |
2061 | offsety += INTVAL (moffsety), sizey -= INTVAL (moffsety); | |
a4311dfe | 2062 | |
0af5bc3e | 2063 | /* If a memref has both a size and an offset, we can use the smaller size. |
efc981bb | 2064 | We can't do this if the offset isn't known because we must view this |
0af5bc3e | 2065 | memref as being anywhere inside the DECL's MEM. */ |
998d7deb | 2066 | if (MEM_SIZE (x) && moffsetx) |
a4311dfe | 2067 | sizex = INTVAL (MEM_SIZE (x)); |
998d7deb | 2068 | if (MEM_SIZE (y) && moffsety) |
a4311dfe RK |
2069 | sizey = INTVAL (MEM_SIZE (y)); |
2070 | ||
2071 | /* Put the values of the memref with the lower offset in X's values. */ | |
2072 | if (offsetx > offsety) | |
2073 | { | |
2074 | tem = offsetx, offsetx = offsety, offsety = tem; | |
2075 | tem = sizex, sizex = sizey, sizey = tem; | |
2076 | } | |
2077 | ||
2078 | /* If we don't know the size of the lower-offset value, we can't tell | |
2079 | if they conflict. Otherwise, we do the test. */ | |
a6f7c915 | 2080 | return sizex >= 0 && offsety >= offsetx + sizex; |
a4311dfe RK |
2081 | } |
2082 | ||
9ae8ffe7 JL |
2083 | /* True dependence: X is read after store in MEM takes place. */ |
2084 | ||
2085 | int | |
2086 | true_dependence (mem, mem_mode, x, varies) | |
2087 | rtx mem; | |
2088 | enum machine_mode mem_mode; | |
2089 | rtx x; | |
e38fe8e0 | 2090 | int (*varies) PARAMS ((rtx, int)); |
9ae8ffe7 | 2091 | { |
b3694847 | 2092 | rtx x_addr, mem_addr; |
49982682 | 2093 | rtx base; |
9ae8ffe7 JL |
2094 | |
2095 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) | |
2096 | return 1; | |
2097 | ||
c4484b8f RH |
2098 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
2099 | This is used in epilogue deallocation functions. */ | |
2100 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) | |
2101 | return 1; | |
2102 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
2103 | return 1; | |
2104 | ||
41472af8 MM |
2105 | if (DIFFERENT_ALIAS_SETS_P (x, mem)) |
2106 | return 0; | |
2107 | ||
b949ea8b JW |
2108 | /* Unchanging memory can't conflict with non-unchanging memory. |
2109 | A non-unchanging read can conflict with a non-unchanging write. | |
2110 | An unchanging read can conflict with an unchanging write since | |
2111 | there may be a single store to this address to initialize it. | |
ec569656 RK |
2112 | Note that an unchanging store can conflict with a non-unchanging read |
2113 | since we have to make conservative assumptions when we have a | |
2114 | record with readonly fields and we are copying the whole thing. | |
b949ea8b JW |
2115 | Just fall through to the code below to resolve potential conflicts. |
2116 | This won't handle all cases optimally, but the possible performance | |
2117 | loss should be negligible. */ | |
ec569656 | 2118 | if (RTX_UNCHANGING_P (x) && ! RTX_UNCHANGING_P (mem)) |
9ae8ffe7 JL |
2119 | return 0; |
2120 | ||
a4311dfe RK |
2121 | if (nonoverlapping_memrefs_p (mem, x)) |
2122 | return 0; | |
2123 | ||
56ee9281 RH |
2124 | if (mem_mode == VOIDmode) |
2125 | mem_mode = GET_MODE (mem); | |
2126 | ||
eab5c70a BS |
2127 | x_addr = get_addr (XEXP (x, 0)); |
2128 | mem_addr = get_addr (XEXP (mem, 0)); | |
2129 | ||
55efb413 JW |
2130 | base = find_base_term (x_addr); |
2131 | if (base && (GET_CODE (base) == LABEL_REF | |
2132 | || (GET_CODE (base) == SYMBOL_REF | |
2133 | && CONSTANT_POOL_ADDRESS_P (base)))) | |
2134 | return 0; | |
2135 | ||
eab5c70a | 2136 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), mem_mode)) |
1c72c7f6 JC |
2137 | return 0; |
2138 | ||
eab5c70a BS |
2139 | x_addr = canon_rtx (x_addr); |
2140 | mem_addr = canon_rtx (mem_addr); | |
6e73e666 | 2141 | |
0211b6ab JW |
2142 | if (! memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr, |
2143 | SIZE_FOR_MODE (x), x_addr, 0)) | |
2144 | return 0; | |
2145 | ||
c6df88cb | 2146 | if (aliases_everything_p (x)) |
0211b6ab JW |
2147 | return 1; |
2148 | ||
f5143c46 | 2149 | /* We cannot use aliases_everything_p to test MEM, since we must look |
c6df88cb MM |
2150 | at MEM_MODE, rather than GET_MODE (MEM). */ |
2151 | if (mem_mode == QImode || GET_CODE (mem_addr) == AND) | |
a13d4ebf AM |
2152 | return 1; |
2153 | ||
2154 | /* In true_dependence we also allow BLKmode to alias anything. Why | |
2155 | don't we do this in anti_dependence and output_dependence? */ | |
2156 | if (mem_mode == BLKmode || GET_MODE (x) == BLKmode) | |
2157 | return 1; | |
2158 | ||
2159 | return ! fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, | |
2160 | varies); | |
2161 | } | |
2162 | ||
2163 | /* Canonical true dependence: X is read after store in MEM takes place. | |
ca7fd9cd KH |
2164 | Variant of true_dependence which assumes MEM has already been |
2165 | canonicalized (hence we no longer do that here). | |
2166 | The mem_addr argument has been added, since true_dependence computed | |
a13d4ebf AM |
2167 | this value prior to canonicalizing. */ |
2168 | ||
2169 | int | |
2170 | canon_true_dependence (mem, mem_mode, mem_addr, x, varies) | |
2171 | rtx mem, mem_addr, x; | |
2172 | enum machine_mode mem_mode; | |
2173 | int (*varies) PARAMS ((rtx, int)); | |
2174 | { | |
b3694847 | 2175 | rtx x_addr; |
a13d4ebf AM |
2176 | |
2177 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) | |
2178 | return 1; | |
2179 | ||
0fe854a7 RH |
2180 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
2181 | This is used in epilogue deallocation functions. */ | |
2182 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) | |
2183 | return 1; | |
2184 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
2185 | return 1; | |
2186 | ||
a13d4ebf AM |
2187 | if (DIFFERENT_ALIAS_SETS_P (x, mem)) |
2188 | return 0; | |
2189 | ||
2190 | /* If X is an unchanging read, then it can't possibly conflict with any | |
2191 | non-unchanging store. It may conflict with an unchanging write though, | |
2192 | because there may be a single store to this address to initialize it. | |
2193 | Just fall through to the code below to resolve the case where we have | |
2194 | both an unchanging read and an unchanging write. This won't handle all | |
2195 | cases optimally, but the possible performance loss should be | |
2196 | negligible. */ | |
2197 | if (RTX_UNCHANGING_P (x) && ! RTX_UNCHANGING_P (mem)) | |
2198 | return 0; | |
2199 | ||
a4311dfe RK |
2200 | if (nonoverlapping_memrefs_p (x, mem)) |
2201 | return 0; | |
2202 | ||
a13d4ebf AM |
2203 | x_addr = get_addr (XEXP (x, 0)); |
2204 | ||
2205 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), mem_mode)) | |
2206 | return 0; | |
2207 | ||
2208 | x_addr = canon_rtx (x_addr); | |
2209 | if (! memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr, | |
2210 | SIZE_FOR_MODE (x), x_addr, 0)) | |
2211 | return 0; | |
2212 | ||
2213 | if (aliases_everything_p (x)) | |
2214 | return 1; | |
2215 | ||
f5143c46 | 2216 | /* We cannot use aliases_everything_p to test MEM, since we must look |
a13d4ebf AM |
2217 | at MEM_MODE, rather than GET_MODE (MEM). */ |
2218 | if (mem_mode == QImode || GET_CODE (mem_addr) == AND) | |
c6df88cb | 2219 | return 1; |
0211b6ab | 2220 | |
c6df88cb MM |
2221 | /* In true_dependence we also allow BLKmode to alias anything. Why |
2222 | don't we do this in anti_dependence and output_dependence? */ | |
2223 | if (mem_mode == BLKmode || GET_MODE (x) == BLKmode) | |
2224 | return 1; | |
0211b6ab | 2225 | |
eab5c70a BS |
2226 | return ! fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, |
2227 | varies); | |
9ae8ffe7 JL |
2228 | } |
2229 | ||
da7d8304 KH |
2230 | /* Returns nonzero if a write to X might alias a previous read from |
2231 | (or, if WRITEP is nonzero, a write to) MEM. */ | |
9ae8ffe7 | 2232 | |
2c72b78f | 2233 | static int |
c6df88cb | 2234 | write_dependence_p (mem, x, writep) |
9ae8ffe7 JL |
2235 | rtx mem; |
2236 | rtx x; | |
c6df88cb | 2237 | int writep; |
9ae8ffe7 | 2238 | { |
6e73e666 | 2239 | rtx x_addr, mem_addr; |
c6df88cb | 2240 | rtx fixed_scalar; |
49982682 | 2241 | rtx base; |
6e73e666 | 2242 | |
9ae8ffe7 JL |
2243 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) |
2244 | return 1; | |
2245 | ||
c4484b8f RH |
2246 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
2247 | This is used in epilogue deallocation functions. */ | |
2248 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) | |
2249 | return 1; | |
2250 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
2251 | return 1; | |
2252 | ||
eab5c70a BS |
2253 | if (DIFFERENT_ALIAS_SETS_P (x, mem)) |
2254 | return 0; | |
2255 | ||
b949ea8b JW |
2256 | /* Unchanging memory can't conflict with non-unchanging memory. */ |
2257 | if (RTX_UNCHANGING_P (x) != RTX_UNCHANGING_P (mem)) | |
2258 | return 0; | |
2259 | ||
9ae8ffe7 JL |
2260 | /* If MEM is an unchanging read, then it can't possibly conflict with |
2261 | the store to X, because there is at most one store to MEM, and it must | |
2262 | have occurred somewhere before MEM. */ | |
55efb413 JW |
2263 | if (! writep && RTX_UNCHANGING_P (mem)) |
2264 | return 0; | |
2265 | ||
a4311dfe RK |
2266 | if (nonoverlapping_memrefs_p (x, mem)) |
2267 | return 0; | |
2268 | ||
55efb413 JW |
2269 | x_addr = get_addr (XEXP (x, 0)); |
2270 | mem_addr = get_addr (XEXP (mem, 0)); | |
2271 | ||
49982682 JW |
2272 | if (! writep) |
2273 | { | |
55efb413 | 2274 | base = find_base_term (mem_addr); |
49982682 JW |
2275 | if (base && (GET_CODE (base) == LABEL_REF |
2276 | || (GET_CODE (base) == SYMBOL_REF | |
2277 | && CONSTANT_POOL_ADDRESS_P (base)))) | |
2278 | return 0; | |
2279 | } | |
2280 | ||
eab5c70a BS |
2281 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), |
2282 | GET_MODE (mem))) | |
41472af8 MM |
2283 | return 0; |
2284 | ||
eab5c70a BS |
2285 | x_addr = canon_rtx (x_addr); |
2286 | mem_addr = canon_rtx (mem_addr); | |
6e73e666 | 2287 | |
c6df88cb MM |
2288 | if (!memrefs_conflict_p (SIZE_FOR_MODE (mem), mem_addr, |
2289 | SIZE_FOR_MODE (x), x_addr, 0)) | |
2290 | return 0; | |
2291 | ||
ca7fd9cd | 2292 | fixed_scalar |
eab5c70a BS |
2293 | = fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, |
2294 | rtx_addr_varies_p); | |
2295 | ||
c6df88cb MM |
2296 | return (!(fixed_scalar == mem && !aliases_everything_p (x)) |
2297 | && !(fixed_scalar == x && !aliases_everything_p (mem))); | |
2298 | } | |
2299 | ||
2300 | /* Anti dependence: X is written after read in MEM takes place. */ | |
2301 | ||
2302 | int | |
2303 | anti_dependence (mem, x) | |
2304 | rtx mem; | |
2305 | rtx x; | |
2306 | { | |
2307 | return write_dependence_p (mem, x, /*writep=*/0); | |
9ae8ffe7 JL |
2308 | } |
2309 | ||
2310 | /* Output dependence: X is written after store in MEM takes place. */ | |
2311 | ||
2312 | int | |
2313 | output_dependence (mem, x) | |
b3694847 SS |
2314 | rtx mem; |
2315 | rtx x; | |
9ae8ffe7 | 2316 | { |
c6df88cb | 2317 | return write_dependence_p (mem, x, /*writep=*/1); |
9ae8ffe7 | 2318 | } |
c14b9960 JW |
2319 | \f |
2320 | /* A subroutine of nonlocal_mentioned_p, returns 1 if *LOC mentions | |
2321 | something which is not local to the function and is not constant. */ | |
7790df19 JW |
2322 | |
2323 | static int | |
c14b9960 JW |
2324 | nonlocal_mentioned_p_1 (loc, data) |
2325 | rtx *loc; | |
2326 | void *data ATTRIBUTE_UNUSED; | |
7790df19 | 2327 | { |
c14b9960 | 2328 | rtx x = *loc; |
7790df19 | 2329 | rtx base; |
7790df19 JW |
2330 | int regno; |
2331 | ||
c14b9960 JW |
2332 | if (! x) |
2333 | return 0; | |
7790df19 | 2334 | |
c14b9960 | 2335 | switch (GET_CODE (x)) |
7790df19 JW |
2336 | { |
2337 | case SUBREG: | |
2338 | if (GET_CODE (SUBREG_REG (x)) == REG) | |
2339 | { | |
2340 | /* Global registers are not local. */ | |
2341 | if (REGNO (SUBREG_REG (x)) < FIRST_PSEUDO_REGISTER | |
ddef6bc7 | 2342 | && global_regs[subreg_regno (x)]) |
7790df19 JW |
2343 | return 1; |
2344 | return 0; | |
2345 | } | |
2346 | break; | |
2347 | ||
2348 | case REG: | |
2349 | regno = REGNO (x); | |
2350 | /* Global registers are not local. */ | |
2351 | if (regno < FIRST_PSEUDO_REGISTER && global_regs[regno]) | |
2352 | return 1; | |
2353 | return 0; | |
2354 | ||
2355 | case SCRATCH: | |
2356 | case PC: | |
2357 | case CC0: | |
2358 | case CONST_INT: | |
2359 | case CONST_DOUBLE: | |
69ef87e2 | 2360 | case CONST_VECTOR: |
7790df19 JW |
2361 | case CONST: |
2362 | case LABEL_REF: | |
2363 | return 0; | |
2364 | ||
2365 | case SYMBOL_REF: | |
2366 | /* Constants in the function's constants pool are constant. */ | |
2367 | if (CONSTANT_POOL_ADDRESS_P (x)) | |
2368 | return 0; | |
2369 | return 1; | |
2370 | ||
2371 | case CALL: | |
bf6d9fd7 | 2372 | /* Non-constant calls and recursion are not local. */ |
7790df19 JW |
2373 | return 1; |
2374 | ||
2375 | case MEM: | |
2376 | /* Be overly conservative and consider any volatile memory | |
2377 | reference as not local. */ | |
2378 | if (MEM_VOLATILE_P (x)) | |
2379 | return 1; | |
2380 | base = find_base_term (XEXP (x, 0)); | |
2381 | if (base) | |
2382 | { | |
b3b5ad95 JL |
2383 | /* A Pmode ADDRESS could be a reference via the structure value |
2384 | address or static chain. Such memory references are nonlocal. | |
2385 | ||
2386 | Thus, we have to examine the contents of the ADDRESS to find | |
2387 | out if this is a local reference or not. */ | |
2388 | if (GET_CODE (base) == ADDRESS | |
2389 | && GET_MODE (base) == Pmode | |
2390 | && (XEXP (base, 0) == stack_pointer_rtx | |
2391 | || XEXP (base, 0) == arg_pointer_rtx | |
2392 | #if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM | |
2393 | || XEXP (base, 0) == hard_frame_pointer_rtx | |
2394 | #endif | |
2395 | || XEXP (base, 0) == frame_pointer_rtx)) | |
7790df19 JW |
2396 | return 0; |
2397 | /* Constants in the function's constant pool are constant. */ | |
2398 | if (GET_CODE (base) == SYMBOL_REF && CONSTANT_POOL_ADDRESS_P (base)) | |
2399 | return 0; | |
2400 | } | |
2401 | return 1; | |
2402 | ||
bf6d9fd7 | 2403 | case UNSPEC_VOLATILE: |
7790df19 | 2404 | case ASM_INPUT: |
7790df19 JW |
2405 | return 1; |
2406 | ||
bf6d9fd7 JW |
2407 | case ASM_OPERANDS: |
2408 | if (MEM_VOLATILE_P (x)) | |
2409 | return 1; | |
2410 | ||
2411 | /* FALLTHROUGH */ | |
2412 | ||
7790df19 JW |
2413 | default: |
2414 | break; | |
2415 | } | |
2416 | ||
c14b9960 JW |
2417 | return 0; |
2418 | } | |
2419 | ||
da7d8304 | 2420 | /* Returns nonzero if X might mention something which is not |
c14b9960 | 2421 | local to the function and is not constant. */ |
7790df19 | 2422 | |
c14b9960 JW |
2423 | static int |
2424 | nonlocal_mentioned_p (x) | |
2425 | rtx x; | |
2426 | { | |
2427 | ||
2428 | if (INSN_P (x)) | |
2429 | { | |
2430 | if (GET_CODE (x) == CALL_INSN) | |
2431 | { | |
2432 | if (! CONST_OR_PURE_CALL_P (x)) | |
2433 | return 1; | |
2434 | x = CALL_INSN_FUNCTION_USAGE (x); | |
2435 | if (x == 0) | |
2436 | return 0; | |
ca7fd9cd | 2437 | } |
c14b9960 | 2438 | else |
ca7fd9cd | 2439 | x = PATTERN (x); |
c14b9960 JW |
2440 | } |
2441 | ||
2442 | return for_each_rtx (&x, nonlocal_mentioned_p_1, NULL); | |
2443 | } | |
2444 | ||
2445 | /* A subroutine of nonlocal_referenced_p, returns 1 if *LOC references | |
2446 | something which is not local to the function and is not constant. */ | |
2447 | ||
2448 | static int | |
2449 | nonlocal_referenced_p_1 (loc, data) | |
2450 | rtx *loc; | |
2451 | void *data ATTRIBUTE_UNUSED; | |
2452 | { | |
2453 | rtx x = *loc; | |
2454 | ||
2455 | if (! x) | |
2456 | return 0; | |
2457 | ||
2458 | switch (GET_CODE (x)) | |
2459 | { | |
2460 | case MEM: | |
2461 | case REG: | |
2462 | case SYMBOL_REF: | |
2463 | case SUBREG: | |
2464 | return nonlocal_mentioned_p (x); | |
2465 | ||
2466 | case CALL: | |
2467 | /* Non-constant calls and recursion are not local. */ | |
2468 | return 1; | |
2469 | ||
2470 | case SET: | |
2471 | if (nonlocal_mentioned_p (SET_SRC (x))) | |
2472 | return 1; | |
2473 | ||
2474 | if (GET_CODE (SET_DEST (x)) == MEM) | |
2475 | return nonlocal_mentioned_p (XEXP (SET_DEST (x), 0)); | |
2476 | ||
2477 | /* If the destination is anything other than a CC0, PC, | |
2478 | MEM, REG, or a SUBREG of a REG that occupies all of | |
2479 | the REG, then X references nonlocal memory if it is | |
2480 | mentioned in the destination. */ | |
2481 | if (GET_CODE (SET_DEST (x)) != CC0 | |
2482 | && GET_CODE (SET_DEST (x)) != PC | |
2483 | && GET_CODE (SET_DEST (x)) != REG | |
2484 | && ! (GET_CODE (SET_DEST (x)) == SUBREG | |
2485 | && GET_CODE (SUBREG_REG (SET_DEST (x))) == REG | |
2486 | && (((GET_MODE_SIZE (GET_MODE (SUBREG_REG (SET_DEST (x)))) | |
2487 | + (UNITS_PER_WORD - 1)) / UNITS_PER_WORD) | |
2488 | == ((GET_MODE_SIZE (GET_MODE (SET_DEST (x))) | |
2489 | + (UNITS_PER_WORD - 1)) / UNITS_PER_WORD)))) | |
2490 | return nonlocal_mentioned_p (SET_DEST (x)); | |
2491 | return 0; | |
2492 | ||
2493 | case CLOBBER: | |
2494 | if (GET_CODE (XEXP (x, 0)) == MEM) | |
2495 | return nonlocal_mentioned_p (XEXP (XEXP (x, 0), 0)); | |
2496 | return 0; | |
2497 | ||
2498 | case USE: | |
2499 | return nonlocal_mentioned_p (XEXP (x, 0)); | |
2500 | ||
2501 | case ASM_INPUT: | |
2502 | case UNSPEC_VOLATILE: | |
2503 | return 1; | |
2504 | ||
2505 | case ASM_OPERANDS: | |
2506 | if (MEM_VOLATILE_P (x)) | |
2507 | return 1; | |
2508 | ||
2509 | /* FALLTHROUGH */ | |
2510 | ||
2511 | default: | |
2512 | break; | |
2513 | } | |
2514 | ||
2515 | return 0; | |
2516 | } | |
2517 | ||
da7d8304 | 2518 | /* Returns nonzero if X might reference something which is not |
c14b9960 JW |
2519 | local to the function and is not constant. */ |
2520 | ||
2521 | static int | |
2522 | nonlocal_referenced_p (x) | |
2523 | rtx x; | |
2524 | { | |
2525 | ||
2526 | if (INSN_P (x)) | |
2527 | { | |
2528 | if (GET_CODE (x) == CALL_INSN) | |
2529 | { | |
2530 | if (! CONST_OR_PURE_CALL_P (x)) | |
2531 | return 1; | |
2532 | x = CALL_INSN_FUNCTION_USAGE (x); | |
2533 | if (x == 0) | |
2534 | return 0; | |
ca7fd9cd | 2535 | } |
c14b9960 | 2536 | else |
ca7fd9cd | 2537 | x = PATTERN (x); |
c14b9960 JW |
2538 | } |
2539 | ||
2540 | return for_each_rtx (&x, nonlocal_referenced_p_1, NULL); | |
2541 | } | |
2542 | ||
2543 | /* A subroutine of nonlocal_set_p, returns 1 if *LOC sets | |
2544 | something which is not local to the function and is not constant. */ | |
2545 | ||
2546 | static int | |
2547 | nonlocal_set_p_1 (loc, data) | |
2548 | rtx *loc; | |
2549 | void *data ATTRIBUTE_UNUSED; | |
2550 | { | |
2551 | rtx x = *loc; | |
2552 | ||
2553 | if (! x) | |
2554 | return 0; | |
2555 | ||
2556 | switch (GET_CODE (x)) | |
2557 | { | |
2558 | case CALL: | |
2559 | /* Non-constant calls and recursion are not local. */ | |
2560 | return 1; | |
2561 | ||
2562 | case PRE_INC: | |
2563 | case PRE_DEC: | |
2564 | case POST_INC: | |
2565 | case POST_DEC: | |
2566 | case PRE_MODIFY: | |
2567 | case POST_MODIFY: | |
2568 | return nonlocal_mentioned_p (XEXP (x, 0)); | |
2569 | ||
2570 | case SET: | |
2571 | if (nonlocal_mentioned_p (SET_DEST (x))) | |
2572 | return 1; | |
2573 | return nonlocal_set_p (SET_SRC (x)); | |
2574 | ||
2575 | case CLOBBER: | |
2576 | return nonlocal_mentioned_p (XEXP (x, 0)); | |
2577 | ||
2578 | case USE: | |
2579 | return 0; | |
2580 | ||
2581 | case ASM_INPUT: | |
2582 | case UNSPEC_VOLATILE: | |
2583 | return 1; | |
2584 | ||
2585 | case ASM_OPERANDS: | |
2586 | if (MEM_VOLATILE_P (x)) | |
2587 | return 1; | |
2588 | ||
2589 | /* FALLTHROUGH */ | |
2590 | ||
2591 | default: | |
2592 | break; | |
2593 | } | |
7790df19 JW |
2594 | |
2595 | return 0; | |
2596 | } | |
2597 | ||
da7d8304 | 2598 | /* Returns nonzero if X might set something which is not |
c14b9960 JW |
2599 | local to the function and is not constant. */ |
2600 | ||
2601 | static int | |
2602 | nonlocal_set_p (x) | |
2603 | rtx x; | |
2604 | { | |
2605 | ||
2606 | if (INSN_P (x)) | |
2607 | { | |
2608 | if (GET_CODE (x) == CALL_INSN) | |
2609 | { | |
2610 | if (! CONST_OR_PURE_CALL_P (x)) | |
2611 | return 1; | |
2612 | x = CALL_INSN_FUNCTION_USAGE (x); | |
2613 | if (x == 0) | |
2614 | return 0; | |
ca7fd9cd | 2615 | } |
c14b9960 | 2616 | else |
ca7fd9cd | 2617 | x = PATTERN (x); |
c14b9960 JW |
2618 | } |
2619 | ||
2620 | return for_each_rtx (&x, nonlocal_set_p_1, NULL); | |
2621 | } | |
2622 | ||
7790df19 JW |
2623 | /* Mark the function if it is constant. */ |
2624 | ||
2625 | void | |
2626 | mark_constant_function () | |
2627 | { | |
2628 | rtx insn; | |
c14b9960 | 2629 | int nonlocal_memory_referenced; |
7790df19 | 2630 | |
ab780373 | 2631 | if (TREE_READONLY (current_function_decl) |
bf6d9fd7 | 2632 | || DECL_IS_PURE (current_function_decl) |
7790df19 | 2633 | || TREE_THIS_VOLATILE (current_function_decl) |
c14b9960 | 2634 | || TYPE_MODE (TREE_TYPE (current_function_decl)) == VOIDmode |
ab780373 RH |
2635 | || current_function_has_nonlocal_goto |
2636 | || !(*targetm.binds_local_p) (current_function_decl)) | |
7790df19 JW |
2637 | return; |
2638 | ||
e004f2f7 | 2639 | /* A loop might not return which counts as a side effect. */ |
0ecf09f9 | 2640 | if (mark_dfs_back_edges ()) |
e004f2f7 JW |
2641 | return; |
2642 | ||
c14b9960 | 2643 | nonlocal_memory_referenced = 0; |
bf6d9fd7 JW |
2644 | |
2645 | init_alias_analysis (); | |
2646 | ||
c14b9960 | 2647 | /* Determine if this is a constant or pure function. */ |
7790df19 JW |
2648 | |
2649 | for (insn = get_insns (); insn; insn = NEXT_INSN (insn)) | |
c14b9960 JW |
2650 | { |
2651 | if (! INSN_P (insn)) | |
2652 | continue; | |
bf6d9fd7 | 2653 | |
c14b9960 JW |
2654 | if (nonlocal_set_p (insn) || global_reg_mentioned_p (insn) |
2655 | || volatile_refs_p (PATTERN (insn))) | |
ca7fd9cd | 2656 | break; |
7790df19 | 2657 | |
c14b9960 JW |
2658 | if (! nonlocal_memory_referenced) |
2659 | nonlocal_memory_referenced = nonlocal_referenced_p (insn); | |
2660 | } | |
ca7fd9cd | 2661 | |
c14b9960 | 2662 | end_alias_analysis (); |
ca7fd9cd | 2663 | |
7790df19 | 2664 | /* Mark the function. */ |
ca7fd9cd | 2665 | |
c14b9960 JW |
2666 | if (insn) |
2667 | ; | |
2668 | else if (nonlocal_memory_referenced) | |
2669 | DECL_IS_PURE (current_function_decl) = 1; | |
2670 | else | |
bf6d9fd7 | 2671 | TREE_READONLY (current_function_decl) = 1; |
7790df19 | 2672 | } |
c14b9960 | 2673 | \f |
6e73e666 | 2674 | |
6e73e666 JC |
2675 | void |
2676 | init_alias_once () | |
2677 | { | |
b3694847 | 2678 | int i; |
6e73e666 JC |
2679 | |
2680 | #ifndef OUTGOING_REGNO | |
2681 | #define OUTGOING_REGNO(N) N | |
2682 | #endif | |
2683 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) | |
2684 | /* Check whether this register can hold an incoming pointer | |
2685 | argument. FUNCTION_ARG_REGNO_P tests outgoing register | |
ec5c56db | 2686 | numbers, so translate if necessary due to register windows. */ |
6e73e666 JC |
2687 | if (FUNCTION_ARG_REGNO_P (OUTGOING_REGNO (i)) |
2688 | && HARD_REGNO_MODE_OK (i, Pmode)) | |
bf1660a6 JL |
2689 | static_reg_base_value[i] |
2690 | = gen_rtx_ADDRESS (VOIDmode, gen_rtx_REG (Pmode, i)); | |
2691 | ||
bf1660a6 JL |
2692 | static_reg_base_value[STACK_POINTER_REGNUM] |
2693 | = gen_rtx_ADDRESS (Pmode, stack_pointer_rtx); | |
2694 | static_reg_base_value[ARG_POINTER_REGNUM] | |
2695 | = gen_rtx_ADDRESS (Pmode, arg_pointer_rtx); | |
2696 | static_reg_base_value[FRAME_POINTER_REGNUM] | |
2697 | = gen_rtx_ADDRESS (Pmode, frame_pointer_rtx); | |
2698 | #if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM | |
2699 | static_reg_base_value[HARD_FRAME_POINTER_REGNUM] | |
2700 | = gen_rtx_ADDRESS (Pmode, hard_frame_pointer_rtx); | |
2701 | #endif | |
7f243674 JL |
2702 | |
2703 | alias_sets = splay_tree_new (splay_tree_compare_ints, 0, 0); | |
bf1660a6 JL |
2704 | } |
2705 | ||
c13e8210 MM |
2706 | /* Initialize the aliasing machinery. Initialize the REG_KNOWN_VALUE |
2707 | array. */ | |
2708 | ||
9ae8ffe7 JL |
2709 | void |
2710 | init_alias_analysis () | |
2711 | { | |
2712 | int maxreg = max_reg_num (); | |
ea64ef27 | 2713 | int changed, pass; |
b3694847 SS |
2714 | int i; |
2715 | unsigned int ui; | |
2716 | rtx insn; | |
9ae8ffe7 JL |
2717 | |
2718 | reg_known_value_size = maxreg; | |
2719 | ||
ca7fd9cd | 2720 | reg_known_value |
e05e2395 MM |
2721 | = (rtx *) xcalloc ((maxreg - FIRST_PSEUDO_REGISTER), sizeof (rtx)) |
2722 | - FIRST_PSEUDO_REGISTER; | |
ca7fd9cd | 2723 | reg_known_equiv_p |
e05e2395 | 2724 | = (char*) xcalloc ((maxreg - FIRST_PSEUDO_REGISTER), sizeof (char)) |
9ae8ffe7 | 2725 | - FIRST_PSEUDO_REGISTER; |
9ae8ffe7 | 2726 | |
6e73e666 JC |
2727 | /* Overallocate reg_base_value to allow some growth during loop |
2728 | optimization. Loop unrolling can create a large number of | |
2729 | registers. */ | |
2730 | reg_base_value_size = maxreg * 2; | |
e2500fed GK |
2731 | reg_base_value = (rtx *) ggc_alloc_cleared (reg_base_value_size |
2732 | * sizeof (rtx)); | |
ac606739 | 2733 | |
e05e2395 MM |
2734 | new_reg_base_value = (rtx *) xmalloc (reg_base_value_size * sizeof (rtx)); |
2735 | reg_seen = (char *) xmalloc (reg_base_value_size); | |
de12be17 JC |
2736 | if (! reload_completed && flag_unroll_loops) |
2737 | { | |
ac606739 | 2738 | /* ??? Why are we realloc'ing if we're just going to zero it? */ |
de12be17 JC |
2739 | alias_invariant = (rtx *)xrealloc (alias_invariant, |
2740 | reg_base_value_size * sizeof (rtx)); | |
961192e1 | 2741 | memset ((char *)alias_invariant, 0, reg_base_value_size * sizeof (rtx)); |
de12be17 | 2742 | } |
ec907dd8 JL |
2743 | |
2744 | /* The basic idea is that each pass through this loop will use the | |
2745 | "constant" information from the previous pass to propagate alias | |
2746 | information through another level of assignments. | |
2747 | ||
2748 | This could get expensive if the assignment chains are long. Maybe | |
2749 | we should throttle the number of iterations, possibly based on | |
6e73e666 | 2750 | the optimization level or flag_expensive_optimizations. |
ec907dd8 JL |
2751 | |
2752 | We could propagate more information in the first pass by making use | |
2753 | of REG_N_SETS to determine immediately that the alias information | |
ea64ef27 JL |
2754 | for a pseudo is "constant". |
2755 | ||
2756 | A program with an uninitialized variable can cause an infinite loop | |
2757 | here. Instead of doing a full dataflow analysis to detect such problems | |
2758 | we just cap the number of iterations for the loop. | |
2759 | ||
2760 | The state of the arrays for the set chain in question does not matter | |
2761 | since the program has undefined behavior. */ | |
6e73e666 | 2762 | |
ea64ef27 | 2763 | pass = 0; |
6e73e666 | 2764 | do |
ec907dd8 JL |
2765 | { |
2766 | /* Assume nothing will change this iteration of the loop. */ | |
2767 | changed = 0; | |
2768 | ||
ec907dd8 JL |
2769 | /* We want to assign the same IDs each iteration of this loop, so |
2770 | start counting from zero each iteration of the loop. */ | |
2771 | unique_id = 0; | |
2772 | ||
f5143c46 | 2773 | /* We're at the start of the function each iteration through the |
ec907dd8 | 2774 | loop, so we're copying arguments. */ |
83bbd9b6 | 2775 | copying_arguments = true; |
9ae8ffe7 | 2776 | |
6e73e666 | 2777 | /* Wipe the potential alias information clean for this pass. */ |
961192e1 | 2778 | memset ((char *) new_reg_base_value, 0, reg_base_value_size * sizeof (rtx)); |
8072f69c | 2779 | |
6e73e666 | 2780 | /* Wipe the reg_seen array clean. */ |
961192e1 | 2781 | memset ((char *) reg_seen, 0, reg_base_value_size); |
9ae8ffe7 | 2782 | |
6e73e666 JC |
2783 | /* Mark all hard registers which may contain an address. |
2784 | The stack, frame and argument pointers may contain an address. | |
2785 | An argument register which can hold a Pmode value may contain | |
2786 | an address even if it is not in BASE_REGS. | |
8072f69c | 2787 | |
6e73e666 JC |
2788 | The address expression is VOIDmode for an argument and |
2789 | Pmode for other registers. */ | |
2790 | ||
7f243674 JL |
2791 | memcpy (new_reg_base_value, static_reg_base_value, |
2792 | FIRST_PSEUDO_REGISTER * sizeof (rtx)); | |
6e73e666 | 2793 | |
ec907dd8 JL |
2794 | /* Walk the insns adding values to the new_reg_base_value array. */ |
2795 | for (insn = get_insns (); insn; insn = NEXT_INSN (insn)) | |
9ae8ffe7 | 2796 | { |
2c3c49de | 2797 | if (INSN_P (insn)) |
ec907dd8 | 2798 | { |
6e73e666 | 2799 | rtx note, set; |
efc9bd41 RK |
2800 | |
2801 | #if defined (HAVE_prologue) || defined (HAVE_epilogue) | |
f5143c46 | 2802 | /* The prologue/epilogue insns are not threaded onto the |
657959ca JL |
2803 | insn chain until after reload has completed. Thus, |
2804 | there is no sense wasting time checking if INSN is in | |
2805 | the prologue/epilogue until after reload has completed. */ | |
2806 | if (reload_completed | |
2807 | && prologue_epilogue_contains (insn)) | |
efc9bd41 RK |
2808 | continue; |
2809 | #endif | |
2810 | ||
ec907dd8 JL |
2811 | /* If this insn has a noalias note, process it, Otherwise, |
2812 | scan for sets. A simple set will have no side effects | |
ec5c56db | 2813 | which could change the base value of any other register. */ |
6e73e666 | 2814 | |
ec907dd8 | 2815 | if (GET_CODE (PATTERN (insn)) == SET |
efc9bd41 RK |
2816 | && REG_NOTES (insn) != 0 |
2817 | && find_reg_note (insn, REG_NOALIAS, NULL_RTX)) | |
84832317 | 2818 | record_set (SET_DEST (PATTERN (insn)), NULL_RTX, NULL); |
ec907dd8 | 2819 | else |
84832317 | 2820 | note_stores (PATTERN (insn), record_set, NULL); |
6e73e666 JC |
2821 | |
2822 | set = single_set (insn); | |
2823 | ||
2824 | if (set != 0 | |
2825 | && GET_CODE (SET_DEST (set)) == REG | |
fb6754f0 | 2826 | && REGNO (SET_DEST (set)) >= FIRST_PSEUDO_REGISTER) |
6e73e666 | 2827 | { |
fb6754f0 | 2828 | unsigned int regno = REGNO (SET_DEST (set)); |
713f41f9 BS |
2829 | rtx src = SET_SRC (set); |
2830 | ||
2831 | if (REG_NOTES (insn) != 0 | |
2832 | && (((note = find_reg_note (insn, REG_EQUAL, 0)) != 0 | |
2833 | && REG_N_SETS (regno) == 1) | |
2834 | || (note = find_reg_note (insn, REG_EQUIV, NULL_RTX)) != 0) | |
2835 | && GET_CODE (XEXP (note, 0)) != EXPR_LIST | |
bb2cf916 | 2836 | && ! rtx_varies_p (XEXP (note, 0), 1) |
713f41f9 BS |
2837 | && ! reg_overlap_mentioned_p (SET_DEST (set), XEXP (note, 0))) |
2838 | { | |
2839 | reg_known_value[regno] = XEXP (note, 0); | |
2840 | reg_known_equiv_p[regno] = REG_NOTE_KIND (note) == REG_EQUIV; | |
2841 | } | |
2842 | else if (REG_N_SETS (regno) == 1 | |
2843 | && GET_CODE (src) == PLUS | |
2844 | && GET_CODE (XEXP (src, 0)) == REG | |
fb6754f0 BS |
2845 | && REGNO (XEXP (src, 0)) >= FIRST_PSEUDO_REGISTER |
2846 | && (reg_known_value[REGNO (XEXP (src, 0))]) | |
713f41f9 BS |
2847 | && GET_CODE (XEXP (src, 1)) == CONST_INT) |
2848 | { | |
2849 | rtx op0 = XEXP (src, 0); | |
bb2cf916 | 2850 | op0 = reg_known_value[REGNO (op0)]; |
713f41f9 | 2851 | reg_known_value[regno] |
ed8908e7 | 2852 | = plus_constant (op0, INTVAL (XEXP (src, 1))); |
713f41f9 BS |
2853 | reg_known_equiv_p[regno] = 0; |
2854 | } | |
2855 | else if (REG_N_SETS (regno) == 1 | |
2856 | && ! rtx_varies_p (src, 1)) | |
2857 | { | |
2858 | reg_known_value[regno] = src; | |
2859 | reg_known_equiv_p[regno] = 0; | |
2860 | } | |
6e73e666 | 2861 | } |
ec907dd8 JL |
2862 | } |
2863 | else if (GET_CODE (insn) == NOTE | |
2864 | && NOTE_LINE_NUMBER (insn) == NOTE_INSN_FUNCTION_BEG) | |
83bbd9b6 | 2865 | copying_arguments = false; |
6e73e666 | 2866 | } |
ec907dd8 | 2867 | |
6e73e666 | 2868 | /* Now propagate values from new_reg_base_value to reg_base_value. */ |
e51712db | 2869 | for (ui = 0; ui < reg_base_value_size; ui++) |
6e73e666 | 2870 | { |
e51712db KG |
2871 | if (new_reg_base_value[ui] |
2872 | && new_reg_base_value[ui] != reg_base_value[ui] | |
2873 | && ! rtx_equal_p (new_reg_base_value[ui], reg_base_value[ui])) | |
ec907dd8 | 2874 | { |
e51712db | 2875 | reg_base_value[ui] = new_reg_base_value[ui]; |
6e73e666 | 2876 | changed = 1; |
ec907dd8 | 2877 | } |
9ae8ffe7 | 2878 | } |
9ae8ffe7 | 2879 | } |
6e73e666 | 2880 | while (changed && ++pass < MAX_ALIAS_LOOP_PASSES); |
9ae8ffe7 JL |
2881 | |
2882 | /* Fill in the remaining entries. */ | |
2883 | for (i = FIRST_PSEUDO_REGISTER; i < maxreg; i++) | |
2884 | if (reg_known_value[i] == 0) | |
2885 | reg_known_value[i] = regno_reg_rtx[i]; | |
2886 | ||
9ae8ffe7 JL |
2887 | /* Simplify the reg_base_value array so that no register refers to |
2888 | another register, except to special registers indirectly through | |
2889 | ADDRESS expressions. | |
2890 | ||
2891 | In theory this loop can take as long as O(registers^2), but unless | |
2892 | there are very long dependency chains it will run in close to linear | |
ea64ef27 JL |
2893 | time. |
2894 | ||
2895 | This loop may not be needed any longer now that the main loop does | |
2896 | a better job at propagating alias information. */ | |
2897 | pass = 0; | |
9ae8ffe7 JL |
2898 | do |
2899 | { | |
2900 | changed = 0; | |
ea64ef27 | 2901 | pass++; |
e51712db | 2902 | for (ui = 0; ui < reg_base_value_size; ui++) |
9ae8ffe7 | 2903 | { |
e51712db | 2904 | rtx base = reg_base_value[ui]; |
9ae8ffe7 JL |
2905 | if (base && GET_CODE (base) == REG) |
2906 | { | |
fb6754f0 | 2907 | unsigned int base_regno = REGNO (base); |
e51712db KG |
2908 | if (base_regno == ui) /* register set from itself */ |
2909 | reg_base_value[ui] = 0; | |
9ae8ffe7 | 2910 | else |
e51712db | 2911 | reg_base_value[ui] = reg_base_value[base_regno]; |
9ae8ffe7 JL |
2912 | changed = 1; |
2913 | } | |
2914 | } | |
2915 | } | |
ea64ef27 | 2916 | while (changed && pass < MAX_ALIAS_LOOP_PASSES); |
9ae8ffe7 | 2917 | |
e05e2395 MM |
2918 | /* Clean up. */ |
2919 | free (new_reg_base_value); | |
ec907dd8 | 2920 | new_reg_base_value = 0; |
e05e2395 | 2921 | free (reg_seen); |
9ae8ffe7 JL |
2922 | reg_seen = 0; |
2923 | } | |
2924 | ||
2925 | void | |
2926 | end_alias_analysis () | |
2927 | { | |
e05e2395 | 2928 | free (reg_known_value + FIRST_PSEUDO_REGISTER); |
9ae8ffe7 | 2929 | reg_known_value = 0; |
ac606739 | 2930 | reg_known_value_size = 0; |
e05e2395 MM |
2931 | free (reg_known_equiv_p + FIRST_PSEUDO_REGISTER); |
2932 | reg_known_equiv_p = 0; | |
e2500fed | 2933 | reg_base_value = 0; |
9ae8ffe7 | 2934 | reg_base_value_size = 0; |
de12be17 JC |
2935 | if (alias_invariant) |
2936 | { | |
ac606739 | 2937 | free (alias_invariant); |
de12be17 JC |
2938 | alias_invariant = 0; |
2939 | } | |
9ae8ffe7 | 2940 | } |
e2500fed GK |
2941 | |
2942 | #include "gt-alias.h" |